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1

Vertical cup-to-disc ratio measurement for diagnosis of glaucoma on fundus images  

NASA Astrophysics Data System (ADS)

Glaucoma is a leading cause of permanent blindness. Retinal fundus image examination is useful for early detection of glaucoma. In order to evaluate the presence of glaucoma, the ophthalmologists determine the cup and disc areas and they diagnose glaucoma using a vertical cup-to-disc ratio. However, determination of the cup area is very difficult, thus we propose a method to measure the cup-to-disc ratio using a vertical profile on the optic disc. First, the blood vessels were erased from the image and then the edge of optic disc was then detected by use of a canny edge detection filter. Twenty profiles were then obtained around the center of the optic disc in the vertical direction on blue channel of the color image, and the profile was smoothed by averaging these profiles. After that, the edge of the cup area on the vertical profile was determined by thresholding technique. Lastly, the vertical cup-to-disc ratio was calculated. Using seventy nine images, including twenty five glaucoma images, the sensitivity of 80% and a specificity of 85% were achieved with this method. These results indicated that this method can be useful for the analysis of the optic disc in glaucoma examinations.

Hatanaka, Yuji; Noudo, Atsushi; Muramatsu, Chisako; Sawada, Akira; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

2010-03-01

2

Automated determination of cup-to-disc ratio for classification of glaucomatous and normal eyes on stereo retinal fundus images  

NASA Astrophysics Data System (ADS)

Early diagnosis of glaucoma, which is the second leading cause of blindness in the world, can halt or slow the progression of the disease. We propose an automated method for analyzing the optic disc and measuring the cup-to-disc ratio (CDR) on stereo retinal fundus images to improve ophthalmologists' diagnostic efficiency and potentially reduce the variation on the CDR measurement. The method was developed using 80 retinal fundus image pairs, including 25 glaucomatous, and 55 nonglaucomatous eyes, obtained at our institution. A disc region was segmented using the active contour method with the brightness and edge information. The segmentation of a cup region was performed using a depth map of the optic disc, which was reconstructed on the basis of the stereo disparity. The CDRs were measured and compared with those determined using the manual segmentation results by an expert ophthalmologist. The method was applied to a new database which consisted of 98 stereo image pairs including 60 and 30 pairs with and without signs of glaucoma, respectively. Using the CDRs, an area under the receiver operating characteristic curve of 0.90 was obtained for classification of the glaucomatous and nonglaucomatous eyes. The result indicates potential usefulness of the automated determination of CDRs for the diagnosis of glaucoma.

Muramatsu, Chisako; Nakagawa, Toshiaki; Sawada, Akira; Hatanaka, Yuji; Yamamoto, Tetsuya; Fujita, Hiroshi

2011-09-01

3

Determination of cup-to-disc ratio of optical nerve head for diagnosis of glaucoma on stereo retinal fundus image pairs  

NASA Astrophysics Data System (ADS)

A large cup-to-disc (C/D) ratio, which is the ratio of the diameter of the depression (cup) to that of the optical nerve head (ONH, disc), can be one of the important signs for diagnosis of glaucoma. Eighty eyes, including 25 eyes with the signs of glaucoma, were imaged by a stereo retinal fundus camera. An ophthalmologist provided the outlines of cup and disc on a regular monitor and on the stereo display. The depth image of the ONH was created by determining the corresponding pixels in a pair of images based on the correlation coefficient in localized regions. The areas of the disc and cup were determined by use of the red component in one of the color images and by use of the depth image, respectively. The C/D ratio was determined based on the largest vertical lengths in the cup and disc areas, which was then compared with that by the ophthalmologist. The disc areas determined by the computerized method agreed relatively well with those determined by the ophthalmologist, whereas the agreement for the cup areas was somewhat lower. When C/D ratios were employed for distinction between the glaucomatous and non-glaucomatous eyes, the area under the receiver operating characteristic curve (AUC) was 0.83. The computerized analysis of ONH can be useful for diagnosis of glaucoma.

Muramatsu, Chisako; Nakagawa, Toshiaki; Sawada, Akira; Hatanaka, Yuji; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

2009-02-01

4

Facile Route to Vertically Aligned High-Aspect Ratio Block Copolymer Films via Dynamic Zone Annealing  

NASA Astrophysics Data System (ADS)

Directed assembly of block copolymers (BCP) can be used to fabricate a diversity of nanostructures useful for nanotech applications. The ability to vertically orient etchable high aspect ratio (˜30) ordered BCP domains on flexible substrates via continuous processing methods are particularly attractive for nanomanufacturing. We apply sharp dynamic cold zone annealing (CZA-S) to create etchable, and predominantly vertically oriented 30nm cylindrical domains in 1 ?m thick poly(styrene-b-methylmethacrylate) films on low thermal conductivity rigid (quartz) and flexible (PDMS & Kapton) substrates. Under similar static conditions, temporally stable vertical cylinders form within a narrow zone above a critical temperature gradient. Primary ordering mechanism of CZA-S involves sweeping this vertically orienting zone created at maximum thermal gradient. An optimal speed is needed since the process competes with preferential surface wetting dynamics that favors parallel orientation. GISAXS of etched BCP films confirms internal morphology.

Singh, Gurpreet; Kulkarni, Manish; Yager, Kevin; Smilgies, Detlef; Bucknall, David; Karim, Alamgir

2012-02-01

5

Large-scale synthesis of arrays of high-aspect-ratio rigid vertically aligned carbon nanofibres  

Microsoft Academic Search

We report on techniques for catalytic synthesis of rigid, high-aspect-ratio, vertically aligned carbon nanofibres by dc plasma enhanced chemical vapour deposition that are tailored for applications that require arrays of individual fibres that feature long fibre lengths (up to 20 µm) such as scanning probe microscopy, penetrant cell and tissue probing arrays and mechanical insertion approaches for gene delivery to

A. V. Melechko; T. E. McKnight; D. K. Hensley; M. A. Guillorn; A. Y. Borisevich; V. I. Merkulov; D. H. Lowndes; M. L. Simpson

2003-01-01

6

Experimental research on heat transfer of natural convection in vertical rectangular channels with large aspect ratio  

SciTech Connect

This work presents the experimental research on the steady laminar natural convection heat transfer of air in three vertical thin rectangular channels with different gap clearance. The much higher ratio of width to gap clearance (60-24) and the ratio of length to gap clearance (800-320) make the rectangular channels similar with the coolant flow passage in plate type fuel reactors. The vertical rectangular channels were composed of two stainless steal plates and were heated by electrical heating rods. The wall temperatures were detected with the K-type thermocouples which were inserted into the blind holes drilled in the steal plates. Also the air temperatures at the inlet and outlet of the channel were detected. The wall heat fluxes added to the air flow were calculated by the Fourier heat conduction law. The heat transfer characteristics were analyzed, and the average Nusselt numbers in all the three channels could be well correlated with the Rayleigh number or the modified Rayleigh number in a uniform correlation. Furthermore, the maximum wall temperatures were investigated, which is a key parameter for the fuel's integrity during some accidents. It was found that even the wall heat flux was up to 1500 W/m{sup 2}, the maximum wall temperature was lower than 350 C. All this work is valuable for the plate type reactor's design and safety analysis. (author)

Lu, Qing; Qiu, Suizheng; Su, Guanghui [State Key Laboratory of Multi Phase Flow in Power Engineering, Xi'an JIaotong University, Xi'an, Shaanxi 710049 (China); School of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China); Tian, Wenxi; Ye, Zhonghao [School of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)

2010-01-15

7

High Rayleigh number convection in rectangular enclosures with differentially heated vertical walls and aspect ratios between zero and unity  

NASA Technical Reports Server (NTRS)

High Rayleigh number convection in a rectangular cavity with insulated horizontal surfaces and differentially heated vertical walls was analyzed for an arbitrary aspect ratio smaller than or equal to unity. Unlike previous analytical studies, a systematic method of solution based on linearization technique and analytical iteration procedure was developed to obtain approximate closed-form solutions for a wide range of aspect ratios. The predicted velocity and temperature fields are shown to be in excellent agreement with available experimental and numerical data.

Kassemi, Siavash A.

1988-01-01

8

Magnetic alignment of high-aspect ratio microwires into vertical arrays  

NASA Astrophysics Data System (ADS)

Fundamental studies of magnetic alignment of highly anisotropic mesostructures can enable the clean-room-free fabrication of flexible, array-based solar and electronic devices, in which preferential orientation of nano- or microwire-type objects is desired. In this study, ensembles of 100 micron long Si microwires with ferromagnetic Ni and Co coatings are oriented vertically in the presence of magnetic fields. The degree of vertical alignment and threshold field strength depend on geometric factors, such as microwire length and ferromagnetic coating thickness, as well as interfacial interactions, which are modulated by varying solvent and substrate surface chemistry. Microwire ensembles with vertical alignment over 97% within 10 degrees of normal, as measured by X-ray diffraction, are achieved over square cm scale areas and set into flexible polymer films. A force balance model has been developed as a predictive tool for magnetic alignment, incorporating magnetic torque and empirically derived surface adhesion parameters. As supported by these calculations, microwires are shown to detach from the surface and align vertically in the presence of magnetic fields on the order of 100 gauss. Microwires aligned in this manner are set into a polydimethylsiloxane film where they retain their vertical alignment after the field has been removed and can subsequently be used as a flexible solar absorber layer. Finally, these microwires arrays can be protected for use in electrochemical cells by the conformal deposition of a graphene layer.

Beardslee, Joseph

9

Length-dependent charge generation from vertical arrays of high-aspect-ratio ZnO nanowires.  

PubMed

Aqueous chemical growth of zinc oxide nanowires is a flexible and effective approach to obtain dense arrays of vertically oriented nanostructures with high aspect ratio. Herein we present a systematic study of the different synthesis parameters that influence the ZnO seed layer and thus the resulting morphological features of the free-standing vertically oriented ZnO nanowires. We obtained a homogeneous coverage of transparent conductive substrates with high-aspect-ratio nanowire arrays (length/diameter ratio of up to 52). Such nanostructured vertical arrays were examined to assess their electric and piezoelectric properties, and showed an electric charge generation upon mechanical compressive stress. The principle of energy harvesting with these nanostructured ZnO arrays was demonstrated by connecting them to an electronic charge amplifier and storing the generated charge in a series of capacitors. We found that the generated charge and the electrical behavior of the ZnO nanowires are strictly dependent on the nanowire length. We have shown the importance of controlling the morphological properties of such ZnO nanostructures for optimizing a nanogenerator device. PMID:24027171

Rivera, Vivian Farías; Auras, Florian; Motto, Paolo; Stassi, Stefano; Canavese, Giancarlo; Celasco, Edvige; Bein, Thomas; Onida, Barbara; Cauda, Valentina

2013-10-18

10

A new method to measure Bowen ratios using high-resolution vertical dry and wet bulb temperature profiles  

NASA Astrophysics Data System (ADS)

The Bowen ratio surface energy balance method is a relatively simple method to determine the latent heat flux and the actual land surface evaporation. The Bowen ratio method is based on the measurement of air temperature and vapour pressure gradients. If these measurements are performed at only two heights, correctness of data becomes critical. In this paper we present the concept of a new measurement method to estimate the Bowen ratio based on vertical dry and wet bulb temperature profiles with high spatial resolution. A short field experiment with distributed temperature sensing (DTS) in a fibre optic cable with 13 measurement points in the vertical was undertaken. A dry and a wetted section of a fibre optic cable were suspended on a 6 m high tower installed over a sugar beet trial plot near Pietermaritzburg (South Africa). Using the DTS cable as a psychrometer, a near continuous observation of vapour pressure and air temperature at 0.20 m intervals was established. These data allowed the computation of the Bowen ratio with a high spatial and temporal precision. The daytime latent and sensible heat fluxes were estimated by combining the Bowen ratio values from the DTS-based system with independent measurements of net radiation and soil heat flux. The sensible heat flux, which is the relevant term to evaluate, derived from the DTS-based Bowen ratio (BR-DTS) was compared with that derived from co-located eddy covariance (R2 = 0.91), surface layer scintillometer (R2 = 0.81) and surface renewal (R2 = 0.86) systems. By using multiple measurement points instead of two, more confidence in the derived Bowen ratio values is obtained.

Euser, T.; Luxemburg, W. M. J.; Everson, C. S.; Mengistu, M. G.; Clulow, A. D.; Bastiaanssen, W. G. M.

2014-06-01

11

Ratios  

NSDL National Science Digital Library

This set of instructional materials and problems helps students understand ratios and proportions, starting with a simple review and progressing into the more advanced territory of similar triangles. The first three pages introduce ratios, proportions, and checking proportionality and the last four pages present mathematical and real-world problems for students to solve given their understanding of ratios and proportions.

Stapel, Elizabeth

2000-01-01

12

A new method to measure bowen ratios using high resolution vertical dry and wet bulb temperature profiles  

NASA Astrophysics Data System (ADS)

The Bowen ratio surface energy balance method is a relatively simple method to determine the latent heat flux and the actual land surface evaporation. Despite its simplicity, the Bowen ratio method is generally considered to be unreliable due to the use of two-level sensors that are installed by default in operational Bowen ratio systems. In this paper we present the concept of a new measurement methodology to estimate the Bowen ratio from high resolution vertical dry and wet bulb temperature profiles. A short field experiment with Distributed Temperature Sensing (DTS) in a fibre optic cable having 13 levels was undertaken. A dry and a wetted section of a fibre optic cable were suspended on a 6 m high tower installed over a sugar beet trial near Pietermaritzburg (South Africa). Using the DTS cable as a psychrometer, a near continuous observation of vapour pressure and temperature at 0.20 m intervals was established. These data allows the computation of the Bowen ratio with a high precision. By linking the Bowen ratio to net radiation and soil heat flux, the daytime latent heat flux was estimated. The latent heat flux derived from DTS-based Bowen ratio (BR-DTS) showed consistent agreement (correlation coefficients between 0.97 and 0.98) with results derived from eddy covariance, surface layer scintillometer and surface renewal techniques. The latent heat from BR-DTS overestimated the latent heat derived with the eddy covariance by 4% and the latent heat derived with the surface layer scintillometer by 8%. Through this research, a new window is opened to engage on simplified, inexpensive and easy to interpret in situ measurement techniques for measuring evaporation.

Euser, T.; Luxemburg, W.; Everson, C.; Mengistu, M.; Clulow, A.; Bastiaanssen, W.

2013-06-01

13

High-aspect-ratio vertically aligned GaAs nanowires fabricated by anodic etching  

NASA Astrophysics Data System (ADS)

Large-scale self-aligned GaAs nanowire arrays were successfully fabricated by the anodic etching of an n-type GaAs (111)B substrate. Although pore generation occurred randomly at the early stage of anodic etching, homogeneous pore growth with a high pore density was accomplished spontaneously on the entire surface of the substrate by prolonged anodic etching under optimized conditions. The GaAs pore walls gradually dissolved during anodic etching and finally three adjacent pores were interconnected to yield a GaAs nanowire with a diameter of approximately 200 nm, a length of approximately 110 μm, and a high aspect ratio of over 500. Aggregates of GaAs nanowires exhibited a good electron emission property, a low turn-on electric field (2.5 V μm−1), and a stable field emission current. The field-emission characteristics were enhanced by increasing the spacing between emission sites through post-chemical etching.

Asoh, Hidetaka; Kotaka, Shunsuke; Ono, Sachiko

2014-12-01

14

Inventory and vertical migration of 90Sr fallout and 137Cs/90Sr ratio in Spanish mainland soils.  

PubMed

In this paper the inventory of (90)Sr in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq/m(2) and 2047 Bq/m(2). From these data set and those (137)Cs data obtained in a previous work the (137)Cs/(90)Sr activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has been analysed obtaining for (137)Cs an average value 57% lower than that obtained for (90)Sr. Additionally, this paper presents the results obtained in 11 sampling points in which the activity vertical profile has been measured. These profiles have been analysed to state the behaviour of strontium in soils and after, by using a convective-diffusive model, the parameters of the model which governs the vertical migration of (90)Sr in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) have been evaluated. Mean values obtained are 0.20 cm/year and 3.67 cm(2)/year, respectively. PMID:21820771

Herranz, M; Romero, L M; Idoeta, R; Olondo, C; Valiño, F; Legarda, F

2011-11-01

15

Nonpolar III-nitride vertical-cavity surface emitting lasers with a polarization ratio of 100% fabricated using photoelectrochemical etching  

NASA Astrophysics Data System (ADS)

Photoelectrochemical (PEC) band gap selective undercut etching is discussed as an alternative technique to chemical-mechanical polishing and laser-lift off for substrate removal for III-nitride vertical-cavity surface-emitting lasers (VCSELs). A top-down PEC etch is also described, which offers the ability to epitaxially define an etch-stop layer, thereby achieving a high degree of cavity length control. The temperature-dependent lasing characteristics of m-plane VCSELs fabricated using PEC etching techniques are analyzed. Measurements of multiple VCSELs from the same wafer yielded lasing emission polarized along the a-direction with a polarization ratio of 100%, indicating that the entire array was uniformly polarized.

Holder, C. O.; Leonard, J. T.; Farrell, R. M.; Cohen, D. A.; Yonkee, B.; Speck, J. S.; DenBaars, S. P.; Nakamura, S.; Feezell, D. F.

2014-07-01

16

Electrochemical growth of vertically-oriented high aspect ratio titania nanotubes by rabid anodization in fluoride-free media.  

PubMed

Vertically-oriented high aspect ratio titania nanotube bundles have been grown by a potentiostatic anodization of titanium sheet in fluoride-free electrolytes. The anodization conditions like the applied voltage were optimized for the synthesis of titania nanotubes in HClO4 and NaCl electrolyte. The resulting nanotubes have a length of about 30 microm, outer diameter about 40 nm, inner pore size of about 10 nm and the aspect ratio was 750:1 by anodization in 0.1 M perchloric acid of pH approximaately 1 at applied voltage of 20 V. While for nanotubes prepared in 0.3 M NaCl of pH 4.3, the length was above 50 microm with the aspect ratio of 1250:1. A method to increase the uniformity of nanotube was demonstrated by pretreatment the titanium sheet by (4 wt% HF + 5 M HNO3) solution prior to anodization. Titania nanotubes were prepared, for the first time, by anodization in aqueous H2SO4 electrolyte alone with tube length above 500 nm. Annealing studies were performed, on high aspect ratio Titania nanotube layers produced in HClO4 electrolyte, in the temperature interval of 300 to 550 degrees C. The XRD patterns and TEM data confirmed the formation of single anatase phase after annealing at 450 degrees C with perfect nanoubular structure. While the rutile titania phase starts to emerege after annealing at about 500 degrees C and the evidence for the appearance of rutile phase due to the oxidation of the underlying Ti metal at the interface between nanotube/Ti-metal was given. On the other hand, the nanotubular structure starts to destroy upon annealing temperature of approximate 550 degrees C by tube flattening and losing of roll-up characteristics as indicated in SEM images. The superior morphology of these high aspect ratio nanotubes and their rapid growth rate foreshadow a bright future in wide applications like dye-sensitized solar cells, water photolysis and nanobiomedical. PMID:19435043

Fahim, Narges Fathy; Sekino, Tohru; Morks, Magdi Farouk; Kusunose, Takafumi

2009-03-01

17

Site Classification Using Horizontal-to-vertical Response Spectral Ratios and its Impact when Deriving Empirical Ground-motion Prediction Equations  

Microsoft Academic Search

We classify sites based on their predominant period computed using average horizontal-to-vertical (H\\/V) response spectral ratios and examine the impact of this classification scheme on empirical ground-motion models. One advantage of this classification is that deep geological profiles and high shear-wave velocities are mapped to the resonance frequency of the site. We apply this classification scheme to the database of

Yoshimitsu Fukushima; Luis Fabián Bonilla; Oona Scotti; John Douglas

2007-01-01

18

Efficiency Enhancement and Beam Shaping of GaN–InGaN Vertical-Injection Light-Emitting Diodes via High-Aspect-Ratio Nanorod Arrays  

Microsoft Academic Search

The enhanced light extraction and collimated output beam profile from GaN-InGaN vertical-injection light-emitting diodes (VI-LEDs) are demonstrated utilizing high-aspect-ratio nanorod arrays. The nanorod arrays are patterned by self-assembled silica spheres, followed by inductively coupled-plasma reactive ion etching. The fabricated nanorod arrays not only provide an omnidirectional escaping zone for photons, but also serve as waveguiding channels for the emitted light,

Min-An Tsai; Peichen Yu; C. L. Chao; C. H. Chiu; H. C. Kuo; S. H. Lin; J. J. Huang; T. C. Lu; S. C. Wang

2009-01-01

19

Impact of the gas flow ratio on the physical properties of GaN grown by vertical flow metalorganic chemical vapour deposition  

NASA Astrophysics Data System (ADS)

We studied the effect of gas flow ratio of the H 2 carrier gas to the NH 3 precursor on the physical and crystal properties of GaN. GaN was grown by vertical reactor metalorganic chemical vapour deposition (MOCVD) on a low-temperature-deposited GaN buffer layer. A (0 0 0 1) sapphire substrate was used. The impact of the gas flow ratio as it was varied from 0.25 to 1 was investigated and discussed. With increase in flow ratio, the concentrations of magnesium and carbon impurities in GaN increased. The flow ratio of 0.5 is the optimum value to minimise the background electron concentration and to maintain crystal quality. The decrease in the background electron concentration is due to the compensation mechanism of acceptor-like magnesium and carbon impurities.

Yuan, Tzu-Tao; Kuei, Ping-Yu; Hsieh, Li-Zen; Li, Ta-Ching; Lin, Wen-Jen

2010-07-01

20

Pollen-ovule relation in Adesmia tristis and reflections on the seed-ovule ratio by interaction with pollinators in two vertical strata.  

PubMed

The vertical distribution of pollinators is an important component in the foraging pattern of plants strata, and it influences the reproductive system (pollen/ovule ratio) and seed/ovule ratio. Niches in two different strata from Adesmia tristis Vogel were evaluated in these aspects. This plant is an endemic shrub from the Campos de Cima da Serra in Southern Brazil. The studies were carried out from January 2010, to January 2011, at Pró-Mata/PUCRS (Catholic University of Rio Grande do Sul) (29°27'-29°35'S and 50°08'-50°15'W), São Francisco de Paula, sate of Rio Grande do Sul, Brazil. Breeding system of A. tristis is mandatory allogamy. The vertical profile in A. tristis has differentiated foraging niches among the most common pollinators. Bees of Megachile genus forage in the upper stratum, and representative bees of the Andrenidae family explore the lower stratum. The upper stratum of the vertical profile had more contribution to seed production. Adesmia tristis showed evidence of pollination deficit. PMID:25211109

Ferreira, Nadilson R; Franke, Lucia B; Blochtein, Betina

2014-09-01

21

Airborne measurements of nonmethane Hydrocarbons over Western Europe: Vertical distributions, seasonal cycles of mixing ratios and source strengths  

NASA Astrophysics Data System (ADS)

Airborne measurements of nonmethane hydrocarbons and methyl chloride in the northern midlatitudinal troposphere over western Europe are reported. Grab samples were analysed by subambient temperature programmed gas chromatography. Using a simple model, annual emission cycles have been calculated from the seasonal variations of mixing ratios. They indicate natrual sources of ethene, propene, i pentane and methyl chloride.

Tille, K. J. W.; Savelsberg, M.; Bächmann, K.

22

Combined raman elastic-backscatter LIDAR for vertical profiling of moisture, aerosol extinction, backscatter, and LIDAR ratio  

Microsoft Academic Search

A combined Raman elastic-backscatter lidar has been developed. A XeCl excimer laser is used as the radiation source. Inelastic Raman backscatter signals are spectrally separated from the elastic signal with a filter or grating polychromator. Raman channels can be chosen to register signals from CO2, O2, N2, and H2O. Algorithms for the calculation of the water-vapor mixing ratio from the

A. Ansmann; M. Riebesell; U. Wandinger; C. Weitkamp; E. Voss; W. Lahmann; W. Michaelis

1992-01-01

23

Inventory and vertical migration of 90Sr fallout and 137Cs\\/ 90Sr ratio in Spanish mainland soils  

Microsoft Academic Search

In this paper the inventory of 90Sr in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq\\/m2 and 2047 Bq\\/m2. From these data set and those 137Cs data obtained in a previous work the 137Cs\\/90Sr activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has

M. Herranz; L. M. Romero; R. Idoeta; C. Olondo; F. Valiño; F. Legarda

2011-01-01

24

Vertical distribution of Th-isotope ratios, 210Pb, 226Ra and 137Cs in sediment cores from an estuary affected by anthropogenic releases.  

PubMed

In an estuary system highly polluted by mining and industrial activities, the sections of sediment cores affected by anthropogenic inputs of U-series radionuclides (due to fertilizer plants releases) were determined through the vertical profiles of Th-isotopic ratio (230Th/232Th). Also, when possible, a modified version of the 210Pb dating method was applied in the uncontaminated sections of these cores. Using the information provided by the Th-isotopic ratio and 210Pb methods, we were able to establish confident chronologies, covering the last century, in several of the analysed sediment cores. These chronologies will be used in forthcoming research to study the time evolution of pollutant concentrations in the estuary. Additionally, and based on the established chronologies, we have found that sedimentation rates have drastically increased in some zones of the estuary since the commencement of several industrial activities in the surrounding environment and since the construction of two dikes in the area. PMID:14654281

San Miguel, E G; Bolívar, J P; García-Tenorio, R

2004-01-01

25

Vertical structure of water masses and silicon-phosphorus ratios in the west Bering Sea and in the Sea of Okhotsk  

NASA Astrophysics Data System (ADS)

Using the data obtained from CTD stations and hydrochemical measurements (oxygen, silicates, and phosphates) performed by the Pacific Scientific Research Fishery Center (TINRO Center) in 2001-2004, vertical structures of water masses were considered for the western Bering Sea and for the deep-water depression of the Sea of Okhotsk. It was shown that definite values of the Si/P molar ratio were characteristic for the water mass boundaries within which linear relationships between these two elements were observed. The lower boundaries of cold intermediate layers in both seas are characterized by a value of Si/P = 23. The ratio for the main halocline (the layer of nutrient concentration jump) is equal to 32, while that for the intermediate layer is equal to 43 (47 in the Sea of Okhotsk). In the Bering Sea, linear relationships between the concentrations of these elements are determined by mixing of waters of different origin. The deep convection, regeneration of phosphates in the lower part of the surface layer, and the significant oxygen deficiency in the intermediate layer determine the doubled inclination of their ratio compared to the Redfield’s parameter. At the same time, in the Sea of Okhotsk, the determining role in linear relationships between the elements considered is played by the aeration of intermediate layer with near-bottom shelf waves, and by tidal mixing.

Vanin, N. S.; Khen, G. V.

2009-06-01

26

Engineered high aspect ratio vertical nanotubes as a model system for the investigation of catalytic methanol synthesis over Cu/ZnO.  

PubMed

Catalytically synthesized methanol from H2 and CO2 using porous Cu/ZnO aggregates is a promising, carbon neutral, and renewable alternative to replace fossil fuel based transport fuels. However, the absence of surface-engineered model systems to understand and improve the industrial Cu/ZnO catalyst poses a big technological gap in efforts to increase industrial methanol conversion efficiency. In this work, we report a novel process for the fabrication of patterned, vertically aligned high aspect ratio 1D nanostructures on Si that can be used as an engineered model catalyst. The proposed strategy employs near-field phase shift lithography (NF-PSL), deep reactive ion etching (DRIE), and atomic layer deposition (ALD) to pattern, etch, and coat Si wafers to produce high aspect ratio 1D nanostructures. Using this method, we produced a model system consisting of high aspect ratio Cu-decorated ZnO nanotubes (NTs) to investigate the morphological effects of ZnO catalyst support in comparison to the planar Cu/ZnO catalyst in terms of the catalytic reactions. The engineered catalysts performed 70 times better in activating CO2 than the industrial catalyst. In light of the obtained results, several important points are highlighted, and recommendations are made to achieve higher catalytic performance. PMID:24392784

Güder, Firat; Frei, Elias; Kücükbayrak, Umut M; Menzel, Andreas; Thomann, Ralf; Luptak, Roman; Hollaender, Bernd; Krossing, Ingo; Zacharias, Margit

2014-02-12

27

Isotopic ratio and vertical distribution of radionuclides in soil affected by the accident of Fukushima Dai-ichi nuclear power plants.  

PubMed

The results of ? analyses of soil samples obtained from 50 locations in Fukushima prefecture on April 20, 2011, revealed the presence of a spectrum of radionuclides resulted from the accident of the Fukushima Dai-ichi nuclear power plant (FDNPP). The sum ? radioactivity concentration ranged in more than 3 orders of magnitude, depending on the sampling locations. The contamination of soils in the northwest of the FDNPP was considerable. The (131)I/(137)Cs activity ratios of the soil samples plotted as a function of the distance from the F1 NPPs exhibited three distinctive patterns. Such patterns would reflect not only the different deposition behaviors of these radionuclides, but also on the conditions of associated release events such as temperature and compositions and physicochemical forms of released radionuclides. The (136)Cs/(137)Cs activity ratio, on the other hand, was considered to only reflect the difference in isotopic compositions of source materials. Two locations close to the NPP in the northwest direction were found to be depleted in short-lived (136)Cs. This likely suggested the presence of distinct sources with different (136)Cs/(137)Cs isotopic ratios, although their details were unknown at present. Vertical ? activity profiles of (131)I and (137)Cs were also investigated, using 20-30 cm soil cores in several locations. About 70% or more of the radionuclides were present in the uppermost 2-cm regions. It was found that the profiles of (131)I/(137)Cs activity ratios showed maxima in the 2-4 cm regions, suggesting slightly larger migration of the former nuclide. PMID:22634028

Fujiwara, Takeshi; Saito, Takumi; Muroya, Yusa; Sawahata, Hiroyuki; Yamashita, Yuji; Nagasaki, Shinya; Okamoto, Koji; Takahashi, Hiroyuki; Uesaka, Mitsuru; Katsumura, Yosuke; Tanaka, Satoru

2012-11-01

28

Evaluation of the horizontal-to-vertical spectral ratio (HVSR) seismic method to determine sediment thickness in the vicinity of the South Well Field, Franklin County, OH  

USGS Publications Warehouse

The horizontal-to-vertical spectral ratio (HVSR) seismic method involves analyzing measurements of ambient seismic noise in three dimensions to determine the fundamental site resonance frequency. Resonance is excited by the interaction of surface waves (Rayleigh and Love) and body waves (vertically incident shear) with the high-contrast aconstic impedance boundary at the bedrock-sediment interface. Measurements were made to determine the method's utility for estimating thickness of unconsolidated glacial sediments at 18 locations at the South Well Field, Franklin County, OH, and at six locations in Pickaway County where sediment thickness was already known. Measurements also were made near a high-capacity production well (with pumping on and off) and near a highway and a limestone quarry to examine changes in resonance frequencies over a 20-hour period. Although the regression relation for resonance frequency and sediment thickness had a relatively low [r.sup.2] (0.322), estimates of sediment thickness were, on average, within 14 percent of known thicknesses. Resonance frequencies for pumping on and pumping off were identical, although the amplitude of the peak was nearly double under pumping conditions. Resonance frequency for the 20-hour period did not change, but the amplitude of the peak changed considerably, with a maximum amplitude in the early afternoon and minimum in the very early morning hours. Clay layers within unconsolidated sediments may influence resonance frequency and the resulting regression equation, resulting in underestimation of sediment thickness; however, despite this and other complicating factors, hydrogeologists should consider this method when thickness data are needed for unconsolidated sediments.

Haefner, Ralph J.; Sheets, Rodney A.; Andrews, Robert E.

2011-01-01

29

Evaluation of the horizontal-to-vertical spectral ratio (HVSR) seismic method to determine sediment thickness in the vicinity of the south well field, Franklin county, OH  

USGS Publications Warehouse

The horizontal-to-vertical spectral ratio (HVSR) seismic method involves analyzing measurements of ambient seismic noise in three dimensions to determine the fundamental site resonance frequency. Resonance is excited by the interaction of surface waves (Rayleigh and Love) and body waves (vertically incident shear) with the high-contrast acoustic impedance boundary at the bedrock-sediment interface. Measurements were made to determine the method's utility for estimating thickness of unconsolidated glacial sediments at 18 locations at the South Well Field, Franklin County, OH, and at six locations in Pickaway County where sediment thickness was already known. Measurements also were made near a high-capacity production well (with pumping on and off ) and near a highway and a limestone quarry to examine changes in resonance frequencies over a 20-hour period. Although the regression relation for resonance frequency and sediment thickness had a relatively low r 2(0.322), estimates of sediment thickness were, on average, within 14 percent of known thicknesses. Resonance frequencies for pumping on and pumping off were identical, although the amplitude of the peak was nearly double under pumping conditions. Resonance frequency for the 20-hour period did not change, but the amplitude of the peak changed considerably, with a maximum amplitude in the early afternoon and minimum in the very early morning hours. Clay layers within unconsolidated sediments may influence resonance frequency and the resulting regression equation, resulting in underestimation of sediment thickness; however, despite this and other complicating factors, hydrogeologists should consider this method when thickness data are needed for unconsolidated sediments. ?? 2011 by The Ohio Academy of Science. All Rights Reserved.

Haefner, R.J.; Sheets, R.A.; Andrews, R.E.

2010-01-01

30

Turbulence modelling of low Reynolds number flow effects around a vertical axis turbine at a range of tip-speed ratios  

NASA Astrophysics Data System (ADS)

This paper presents a two-dimensional numerical investigation of a vertical axis turbine with focus on the prediction from two different turbulence modelling schemes. The three bladed turbine configuration tested is that of Roa et al. (2010) which has a high solidity of 1.1 and is tested at a chord-based Reynolds number of 1.5 × 105. Results are provided at three different tip speed ratios: the optimal value, and values 25% higher and lower. A detailed investigation of the flow ensues and results are presented as obtained from the original SST model and a modified version for low Reynolds number effects, recently tested by Wang et al. (2010) for a similar flow. Post-processing includes the evolution of the skin-friction coefficient over the blade throughout a cycle which enables a better understanding of the flow structure and the dynamic stall effects, as well as blade-vortex interaction. The low Reynolds number version of the model acts to reduce turbulence viscosity, leading to laminar flow at various parts of the cycle, which is seen to correctly enable the formation of leading edge vortices observed in the literature.

McNaughton, J.; Billard, F.; Revell, A.

2014-05-01

31

Effects of influent C/N ratios on wastewater nutrient removal and simultaneous greenhouse gas emission from the combinations of vertical subsurface flow constructed wetlands and earthworm eco-filters for treating synthetic wastewater.  

PubMed

This research focused on the nutrient removal and the simultaneous CO2, CH4, and N2O emission rates of various combinations of vertical subsurface flow constructed wetlands (VSFCWs) and earthworm eco-filters (EEs) under different influent C/N ratios in synthetic wastewater. The optimal parameters for nutrient removal were influent C/N ratios of 5?:?1 and 10?:?1 as well as the combination VSFCW-EE. Relatively low values of greenhouse gas (GHG) emission rates measured in situ were obtained at a C/N ratio of 5?:?1. The emission rates of CH4 and N2O were considerably lower than that of CO2. The VSFCW-EE and EE-VSFCW combinations showed similar GHG emission results. The C/N ratio of 5?:?1 and the VSFCW-EE combination exhibited the highest nutrient removal efficiency with the lowest GHG emission rate. Wastewater nutrient removal and GHG emission were both high during summer (June to August) and low during winter (December to February). PMID:24504343

Zhao, Yongjun; Zhang, Yuejin; Ge, Zhigang; Hu, Changwei; Zhang, Hui

2014-03-01

32

Observation of picometer vertical emittance with a vertical undulator.  

PubMed

Using a vertical undulator, picometer vertical electron beam emittances have been observed at the Australian Synchrotron storage ring. An APPLE-II type undulator was phased to produce a horizontal magnetic field, which creates a synchrotron radiation field that is very sensitive to the vertical electron beam emittance. The measured ratios of undulator spectral peak heights are evaluated by fitting to simulations of the apparatus. With this apparatus immediately available at most existing electron and positron storage rings, we find this to be an appropriate and novel vertical emittance diagnostic. PMID:23215388

Wootton, K P; Boland, M J; Dowd, R; Tan, Y-R E; Cowie, B C C; Papaphilippou, Y; Taylor, G N; Rassool, R P

2012-11-01

33

Vertical Farm  

NSDL National Science Digital Library

With the continued growth of the human population of the Earth, there is increasing concern with the planet's ability to provide sustenance for all of its inhabitants. This compelling website by Dickson Despommier and his colleagues at Columbia University provides a worthy alternative to other forms of agriculture: the vertical farm. As Dr. Despommier notes on the site, "..they offer the promise of urban renewal, sustainable production of a safe and varied food supply (year-round crop production), and the eventual repair of ecosystems that have been sacrificed for horizontal farming." The site offers a great deal of information about these vertical farms, a detailed essay on the importance of such farms, a number of potential designs, and a discussion forum. Finally, there are a number of plans that indicate how this type of farm might be effectively created and sustained.

2004-01-01

34

Optimal segmentation of the optic nerve head from stereo retinal images  

NASA Astrophysics Data System (ADS)

Early detection of glaucoma is essential to minimizing the risk of visual loss. It has been shown that a good predictor of glaucoma is the cup-to-disc ratio of the optic nerve head. This paper presents a highly automated method to segment the 'rim' (disc) and 'cup' from the optic nerve head in stereo images and calculate the cup-to-disc ratio. In this approach, the optic nerve head is unwrapped in polar coordinates and represented as a graph. Utilizing a novel and efficient graph searching technique for determining globally optimal closed-paths and an intelligent cost function, the rim and the cup are segmented from the stereo images. The results offer a more intuitive quantitative analysis compared to current planimetry-based techniques because the ophthalmologist can view the segmented images along with the derived cup-to-disc ratio.

Merickel, Michael B., Jr.; Wu, Xiaodong; Sonka, Milan; Abramoff, Michael

2006-03-01

35

Jamming in Vertical Channels  

NASA Astrophysics Data System (ADS)

We study jamming of low aspect-ratio cylindrical Delrin grains in a vertical channel. Grain heights are less than their diameter so the grains resemble antacid tablets, coins, or poker chips. These grains are allowed to fall through a vertical channel with a square cross section where the channel width is greater than the diameter of a grain and constant throughout the length of the channel with no obstructions or constrictions. Grains are sometimes observed to form jams, stable structures supported by the channel walls with no support beneath them. The probability of jam occurrence and the strength or robustness of a jam is effected by grain and channel sizes. We will present experimental measurements of the jamming probability and jam strength in this system and discuss the relationship of these results to other experiments and theories.

Baxter, G. William; Steel, Fiona

2011-03-01

36

Jamming in Vertical Channels  

NASA Astrophysics Data System (ADS)

We experimentally study jamming of cylindrical grains in a vertical channel. The grains have a low aspect-ratio (height/diameter < 1) so their shape is like antacid tablets or poker chips. They are allowed to fall through a vertical channel with a square cross section. The channel width is greater than the diameter of a grain and constant throughout the length of the channel with no obstructions or constrictions. It is observed that grains sometimes jam in this apparatus. In a jam, grains form a stable structure from one side of the channel to the other with nothing beneath them. Jams may be strong enough to support additional grains above. The probability of a jam occurring is a function of the grain height and diameter. We will present experimental measurements of the jamming probability in this system and discuss the relationship of these results to other experiments and theories.

Baxter, G. William; McCausland, Jeffrey; Steel, Fiona

2010-03-01

37

Vertical solar louver project  

NASA Astrophysics Data System (ADS)

The thermal network analysis computer program MICROPAS was used to analyze Vertical Solar Louvers and other reference solar designs in eight selected climates. The results have been used to generate a set of correlation coefficients for use in performance predictions by the Solar Load Ratio method. At low mass VSL were shown to be superior to ordinary direct gain and equal to the trombe wall systems in energy savings. The energy savings advantage of VSL over direct gain disappears in comparable systems of high mass. Identical solar water tanks of oval cross section were compared in the water wall and VSL configurations.

Bier, C. J.

1984-09-01

38

Depth aftereffects mediated by vertical disparities: Evidence for vertical disparity driven calibration of extraretinal signals during stereopsis  

Microsoft Academic Search

Perceptual adaptation often results in a repulsive aftereffect: stimuli are seen as biased away from the adaptation stimulus (Blakemore & Sutton, 1969). Here we report the absence of a repulsive aftereffect for a vertical gradient of vertical disparity (or vertical size ratio, VSR). We exposed observers to a binocular stimulus consisting of horizontal lines. This stimulus contains vertical, but not

Philip A. Duke; Ipek Orucb; Haijiang Qi; Benjamin T. Backus

2006-01-01

39

Comparison of Different Spectral Domain OCT Scanning Protocols for Diagnosing Preperimetric Glaucoma  

PubMed Central

Purpose. To compare the ability of spectral-domain optical coherence tomography (SDOCT) retinal nerve fiber layer (RNFL), optic nerve head (ONH), and macular measurements to detect preperimetric glaucomatous damage. Methods. The study included 142 eyes from 91 patients suspected of having the disease based on the appearance of the optic disc. All eyes had normal visual fields before the imaging session. Forty-eight eyes with progressive glaucomatous damage were included in the preperimetric glaucoma group. Ninety-four eyes without any evidence of progressive glaucomatous damage and followed untreated for 12.8 ± 3.6 years were used as controls. Areas under the receiver operating characteristic curves (AUC) were calculated to summarize diagnostic accuracies of the parameters. Results. The three RNFL parameters with the largest AUCs were average RNFL thickness (0.89 ± 0.03), inferior hemisphere average thickness (0.87 ± 0.03), and inferior quadrant average thickness (0.85 ± 0.03). The three ONH parameters with the largest AUCs were vertical cup-to-disc ratio (0.74 ± 0.04), rim area (0.72 ± 0.05), and rim volume (0.72 ± 0.05). The three macular parameters with the largest AUCs were GCC average thickness (0.79 ± 0.04), GCC inferior thickness (0.79 ± 0.05), and GCC superior thickness (0.76 ± 0.05). Average RNFL thickness performed better than vertical cup-to-disc ratio (0.89 vs. 0.74; P = 0.007) and GCC average thickness (0.89 vs. 0.79; P = 0.015). Conclusions. SDOCT RNFL measurements performed better than ONH and macular measurements for detecting preperimetric glaucomatous damage in a cohort of glaucoma suspects. (ClinicalTrials.gov number, NCT00221897.) PMID:23532529

Lisboa, Renato; Paranhos, Augusto; Weinreb, Robert N.; Zangwill, Linda M.; Leite, Mauro T.; Medeiros, Felipe A.

2013-01-01

40

Lightning Ratios  

NSDL National Science Digital Library

Using satellites and ground-based detection instruments, researchers have now mapped out lightning ratios for the continental United States. The Lightning Ratios site, from Space Science News (NASA), provides recent data in the form of a vibrant color map (.pdf or .jpg) of cloud-to-cloud lightning to cloud-to-ground lightning over the continental United States.

41

Rod Ratios  

NSDL National Science Digital Library

This activity builds student knowledge of ratios by using Cuisenaire rods to determine proportion and form equivalent ratios. Students may use the Cuisenaire rod environment embedded in this resource or they may use actual Cuisenaire rods depending on preference/ability/accessibility. This resource includes teacher notes, solution, and suggestions for questioning.

Team, Nrich

2013-01-01

42

An Atomatic Fundus Image Analysis System for Clinical Diagnosis of Glaucoma  

Microsoft Academic Search

Glaucoma is a serious ocular disease and leads blindness if it couldn't be detected and treated in proper way. The diagnostic criteria for glaucoma include intraocular pressure measurement, optic nerve head evaluation, retinal nerve fiber layer and visual field defect. The observation of optic nerve head, cup to disc ratio and neural rim configuration are important for early detecting glaucoma

Chih-Yin Ho; Tun-Wen Pai; Hao-Teng Chang; Hsin-Yi Chen

2011-01-01

43

Offset vertical radar profiling  

USGS Publications Warehouse

Diffraction tomography imaging was applied to VRP data acquired by vertically moving a receiving antenna in a number of wells. This procedure simulated a vertical downhole receiver array. Similarly, a transmitting antenna was sequentially moved along a series of radial lines extending outward from the receiver wells. This provided a sequence of multistatic data sets and, from each data set, a two-dimensional vertical cross-sectional image of spatial variations in wave speed was reconstructed.

Witten, A.; Lane, J.

2003-01-01

44

Vertical profiles of condensation nuclei  

NASA Technical Reports Server (NTRS)

Condensation nuclei measurements using a low supersaturation (about 10%) thermal gradient diffusion cloud chamber (TGDCC) and a high supersaturation (about 200%) expansion type instrument were compared on a series of three balloon flights over Laramie, Wyoming. In general, the two instruments produced similar vertical profiles but some discrepancies remain unexplained. Agreement between the two would indicate that the low supersaturations used in the TGDCC were still large enough to cause the instrument to count essentially all of the particles present. The TGDCC condensation nuclei (CN) counter was flown at several sites in both the Northern and Southern Hemispheres. The results indicate the existence of a relative maximum in the CN mixing ratio associated with the upper equatorial troposphere and what appears to be a worldwide constant mixing ratio of CN above 20-25 km.

Rosen, J. M.; Hofmann, D. J.; Kaselau, K. H.

1978-01-01

45

Vertical Line Test  

NSDL National Science Digital Library

In this activity, students try to connect given points on a graph in a way that they will pass the vertical line test. If the points can't be made to pass the vertical line test, the student must adjust the points so they will pass the test. This activity allows students to explore the vertical line test for functions. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

2010-01-01

46

Design of a circularly-polarized vertical patch antenna  

Microsoft Academic Search

A circularly-polarized vertical patch antenna is proposed and investigated. The design is achieved by simply adding two small stubs to the vertical patch. The antenna maintains the advantages of the original linearly polarized vertical patch antenna, such as simple structure, small size and wide bandwidth. It exhibits a gain of 8 dBi over a 3 dB axial ratio bandwidth of

Ka-Lam Lau; Kwai-Man Luk; Kai-Fong Lee

2006-01-01

47

Micromachined electrostatic vertical actuator  

SciTech Connect

A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized in a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion, micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.

Lee, A.P.; Sommargren, G.E.; McConaghy, C.F.; Krulevitch, P.A.

1999-10-19

48

Micromachined electrostatic vertical actuator  

DOEpatents

A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized in a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion` micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.

Lee, Abraham P. (Walnut Creek, CA); Sommargren, Gary E. (Santa Cruz, CA); McConaghy, Charles F. (Livermore, CA); Krulevitch, Peter A. (Pleasanton, CA)

1999-10-19

49

Vertical emitting aperture nanoantennas.  

PubMed

Herein we propose, theoretically investigate, and numerically demonstrate a compact design for a vertical emitter at a wavelength of 1.5 ?m based on nanophotonic aperture antennas coupled to a dielectric waveguide. The structure utilizes a plasmonic antenna placed above a Si3N4 waveguide with a ground plane for breaking the up-down symmetry and increasing the emission efficiency. Three-dimensional (3-D) finite-difference time-domain (FDTD) simulations reveal that up to 60% vertical emission efficiency is possible in a structure only four wavelengths long with a 3 dB bandwidth of over 300 nm. PMID:22555702

Yaacobi, Ami; Timurdogan, Erman; Watts, Michael R

2012-05-01

50

Learning About Ratios  

NSDL National Science Digital Library

Ratios appear in everyday life, but what exactly is a ratio. This lesson will help you understand what is a ratio and what to do with a ratio. What is a ratio? Dr. Math gives a pretty good explanation on these sites What is a ratio? Ratios as Fractions Figuring Ratios Writing Ratios Ratios Use this site to explore ratios using pictures All About Ratios Now that you have a little understanding here are some in-class activities that your teacher can help you with ...

Hadley, Mrs.

2005-06-17

51

Aiding Vertical Guidance Understanding  

NASA Technical Reports Server (NTRS)

A two-part study was conducted to evaluate modern flight deck automation and interfaces. In the first part, a survey was performed to validate the existence of automation surprises with current pilots. Results indicated that pilots were often surprised by the behavior of the automation. There were several surprises that were reported more frequently than others. An experimental study was then performed to evaluate (1) the reduction of automation surprises through training specifically for the vertical guidance logic, and (2) a new display that describes the flight guidance in terms of aircraft behaviors instead of control modes. The study was performed in a simulator that was used to run a complete flight with actual airline pilots. Three groups were used to evaluate the guidance display and training. In the training, condition, participants went through a training program for vertical guidance before flying the simulation. In the display condition, participants ran through the same training program and then flew the experimental scenario with the new Guidance-Flight Mode Annunciator (G-FMA). Results showed improved pilot performance when given training specifically for the vertical guidance logic and greater improvements when given the training and the new G-FMA. Using actual behavior of the avionics to design pilot training and FMA is feasible, and when the automated vertical guidance mode of the Flight Management System is engaged, the display of the guidance mode and targets yields improved pilot performance.

Feary, Michael; McCrobie, Daniel; Alkin, Martin; Sherry, Lance; Polson, Peter; Palmer, Everett; McQuinn, Noreen

1998-01-01

52

Vertical Structure of NGC 4631  

NASA Astrophysics Data System (ADS)

We present a deep CCD imaging in B and V bands which allows us to analyze the vertical structure of NGC 4631. We derive the scale heights of the thin and thick disks at a variety of positions along the major axis of the disk. The scale heights of the thin disk are nearly constant while those of the thick disk tend to increase with increasing galactocentric distance. The mean scale heights of the thin disk derived from B and V images are similar to each other (˜450 pc). Instead, those of the thick disk show a strong east-west asymmetry which is caused by the diffuse stellar emission that is most prominent in the north west regions above the disk plane. The ratio of scale heights (z_{thick}/z_{thin}) is about 2.5 in the east side of the disk. However, this ratio is greater than 4 for the thick disk above the disk plane in the west side of the galaxy.

Ann, Hong Bae; Seo, Mira Seo; Baek, Su-Ja

2011-02-01

53

Ratios and Proportions  

NSDL National Science Digital Library

In this learning object from Wisc-Online, students will examine ratios and proportions. The unit's activities include defining ratios and proportions, simplifying ratios, solving problems using proportions and answering practice questions.

Blohowiak, Chad; Jensen, Douglas; Reed, Allen

2005-01-01

54

Vertical Motion Simulator  

NSDL National Science Digital Library

The Vertical Motion Simulator (VMS), at the NASA Ames Research Center, is an advanced flight simulation facility. This Web site provides thorough descriptions of all of the VMS systems. The VMS is a full immersion environment, complete with customizable cockpit, controls, and instrumentation to give the appearance of any aerospace vehicle. One of its most intriguing characteristics is "out-the-window graphics." This allows the pilot to see computer generated imagery of real locations, so virtually everything is identical to the actual flying experience. Even aircraft that are still in the design stage can be simulated on the VMS.

55

'Endurance' Untouched (vertical)  

NASA Technical Reports Server (NTRS)

This navigation camera mosaic, created from images taken by NASA's Mars Exploration Rover Opportunity on sols 115 and 116 (May 21 and 22, 2004) provides a dramatic view of 'Endurance Crater.' The rover engineering team carefully plotted the safest path into the football field-sized crater, eventually easing the rover down the slopes around sol 130 (June 12, 2004). To the upper left of the crater sits the rover's protective heatshield, which sheltered Opportunity as it passed through the martian atmosphere. The 360-degree view is presented in a vertical projection, with geometric and radiometric seam correction.

2004-01-01

56

Vertical distribution of natural radionuclides in soils  

NASA Astrophysics Data System (ADS)

Low-level alpha spectrometry techniques using semiconductor detectors (PIPS) and liquid scintillation counters (LKB Quantulus 1220™) were used in order to determine the activity concentration of 238U, 232Th, 234U, 230Th, 226Ra, and 210Pb in soil samples. The soils were collected from an old disused uranium mine located in southwest Spain. The soils were selected with different levels of influence from the installation, in such a way that they had different levels of radioactive contamination. The vertical profiles in the soils (down to 40 cm depth) were studied in order to evaluate the vertical distribution of the natural radionuclides. The possible contamination of subsurface waters depends strongly on vertical migration, and the transfer to plants (herbs, shrubs, and trees) also will depend on the distribution of the radionuclides in the root zone. The study of the activity ratios between radionuclides belonging to the same series allowed us to assess the differing behaviour of the radionuclides involved. The vertical profiles for these radionuclides were different at each sampling point, showing the local impact of the installation. However, the profiles per point were similar for the long-lived radionuclides of the 238TJ series (238U, 234U, 230Th, and 226Ra). Also, a major disequilibrium was observed between 210Pb and 226Ra in the surface layer, due to 222Rn emanation and subsequent surface deposition of 210Pb.

Blanco Rodríguez, P.; Tomé, F. Vera; Lozano, J. C.

2012-04-01

57

Energy Balance Bowen Ratio Station (EBBR) Handbook  

SciTech Connect

The energy balance Bowen ratio (EBBR) system produces 30-minute estimates of the vertical fluxes of sensible and latent heat at the local surface. Flux estimates are calculated from observations of net radiation, soil surface heat flux, and the vertical gradients of temperature and relative humidity (RH). Meteorological data collected by the EBBR are used to calculate bulk aerodynamic fluxes, which are used in the Bulk Aerodynamic Technique (BA) EBBR value-added product (VAP) to replace sunrise and sunset spikes in the flux data. A unique aspect of the system is the automatic exchange mechanism (AEM), which helps to reduce errors from instrument offset drift.

Cook, DR

2011-02-23

58

Laser drilling of vertical vias in silicon  

SciTech Connect

Any advance beyond the density of standard 2D Multichip Modules (MCM) will require a vertical interconnect technology that can produce reliable area array interconnection with small feature sizes. Laser drilled vertical vias have been controllably produced in standard silicon (Si) wafers down to 0.035mm (0.0014 inches) in diameter. Several laser systems and their system parameters have been explored to determine the optimum parametric set for repeatable vias in Si. The vias produced have exhibited clean smooth interior surfaces with an aspect ratio of up to 20:1 with little or no taper. All laser systems used, their system parameters, design modifications, theory of operation, and drilling results are discussed.

Miller, W.D.; Gassman, R.A.; Keicher, D.M.

1993-08-01

59

Jamming of Cylindrical Grains in Vertical Channels  

NASA Astrophysics Data System (ADS)

We study jamming of low aspect-ratio cylindrical Delrin grains in a vertical channel. These cylindrical grains resemble antacid tablets, poker chips, or coins since their height is less than their diameter. Grains are allowed to fall through a vertical channel with a square cross section where the channel width is greater than the diameter of a grain and constant throughout the length of the channel with no obstructions or constrictions. Within this channel, grains are sometimes observed to form jams, stable structures supported by the channel walls with no support beneath them. The probability of jam occurrence and the strength or robustness of a jam is effected by the grain dimensions and channel size. We will present experimental measurements of the jamming probability and jam strength in this system and discuss the relationship of these results to other experiments and theories.

Baxter, G. William; Spier, Gregory; Barr, Nicholas; Steel, Fiona

2012-02-01

60

Liquefied strength ratio from liquefaction flow failure case histories  

Microsoft Academic Search

The shear strength of liquefied soil, su(LIQ), mobilized during a liquefaction flow failure is normalized with re- spect to the vertical effective stress ( ? vo ' ) prior to failure to evaluate the liquefied strength ratio, su(LIQ)\\/? vo ' . Liquefied strength ratios mobilized during 33 cases of liquefaction flow failure are estimated using a procedure developed to directly

Scott M. Olson; Timothy D. Stark

2002-01-01

61

4. VIEW OF VERTICAL BORING MACHINE. (Bullard) Vertical turning lathe ...  

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

4. VIEW OF VERTICAL BORING MACHINE. (Bullard) Vertical turning lathe (VTL). Machining the fixture for GE Turboshroud. G.S. O'Brien, operator. - Juniata Shops, Machine Shop No. 1, East of Fourth Avenue at Third Street, Altoona, Blair County, PA

62

Steiner Ratio for Manifolds  

E-print Network

The Steiner ratio characterizes the greatest possible deviation of the length of a minimal spanning tree from the length of the minimal Steiner tree. In this paper, estimates of the Steiner ratio on Riemannian manifolds are obtained. As a corollary, the Steiner ratio for flat tori, flat Klein bottles, and projective plane of constant positive curvature are computed. Steiner ratio - Steiner problem - Gilbert--Pollack conjecture - surfaces of constant curvature

Cieslik, D; Tuzhilin, A A; 10.1023/A:1026106802540

2011-01-01

63

Functions and Vertical Line Test  

NSDL National Science Digital Library

This lesson is designed to introduce students to the vertical line test for functions as well as practice plotting points and drawing simple functions. The lesson provides links to discussions and activities related to the vertical line test and functions as well as suggested ways to integrate them into the lesson.

2010-01-01

64

Vertical profiles of ethane and propane in the stratosphere  

Microsoft Academic Search

Stratospheric measurements of the C2H6 mixing ratio up to 30 km and of the C3H8 mixing ratio up to 18 km altitude are reported. The observed vertical gradient of C2H6 is much weaker than that calculated from a one-dimensional steady state model, indicating lower concentrations of atomic chlorine in the lower stratosphere than those predicted by models. From the measured

J. Rudolph; D. H. Ehhalt; A. Toennissen

1981-01-01

65

Ramp and Ratios  

NSDL National Science Digital Library

In this activity students view and analyze images of ramps and steps to see if they conform to the requirements of the Americans with Disabilities Act. Students measure horizontal and vertical distances and compute the percent slope for each image. Image measurements are performed using WebImage, a Web-based, customized version of ImageJ.

66

Autocalibrating Tiled Projectors on Piecewise Smooth Vertically Extruded Surfaces  

E-print Network

is a piecewise smooth vertically extruded surface for which the aspect ratio of the rectangle formed by the four of the CAVE--a popular immersive VR display system. Finally, this opens up the possibility of easily deploying are common for a large number of applications like gaming, entertainment, and 3D visualiza- tion

Majumder, Aditi

67

Maximum ratio transmission  

Microsoft Academic Search

This paper presents the concept, principles, and analysis of maximum ratio transmission for wireless communications, where multiple antennas are used for both transmission and reception. The principles and analysis are applicable to general cases, including maximum-ratio combining. Simulation results agree with the analysis. The analysis shows that the average overall signal-to-mise ratio (SNR) is proportional to the cross correlation between

Titus K. Y. Lo

1999-01-01

68

IMPACT OF CITY VERTICALIZATION ON URBAN SURFACE ENERGY BUDGET: A MODELING STUDY  

Microsoft Academic Search

The impact of verticalization of cities on local climate is studied with an urban canopy model (UCM) coupled to an atmospheric turbulence model. Simulations with various aspect ratios were performed in order to assess the impact of aspect ratio on urban temperature and energy budget. Results show that net radiation suffers a decreasing as the aspect ratio increase. It is

Edson Marciotto

69

Spectral characteristics of vertical ground motion in the Northridge and other earthquakes  

SciTech Connect

Spectral characteristics of vertical ground motion recorded during the Northridge earthquake are evaluated and compared to those of other earthquakes. Relationship between vertical and horizontal spectra is examined through development of attenuation of vertical and horizontal response spectra. Vertical-to-horizontal response spectral relationship is then compared to that of 1989 Loma Prieta earthquake, and several other earthquakes recorded over SMART-1 array in Taiwan. This preliminary analysis shows that the main characteristics of vertical-to-horizontal spectral ratio are similar to those of other earthquakes. One main characteristic is that in the near-field region and in short period range, the ratio is much higher than commonly assumed ratio of 2/3.

Bozorgnia, Y. [ATS Engineering, Walnut Creek, CA (United States); Niazi, M. [Berkeley Geophysical Consultants, CA (United States); Campbell, K.W. [EQE International, Evergreen, CO (United States)

1995-12-31

70

Finite Element Surface Model for Flow around Vertical Wall Abutments  

NASA Astrophysics Data System (ADS)

A two-dimensional finite element surface model is developed to determine velocities, depths, and turning angles around vertical wall abutments. The model solves the Reynolds-averaged turbulent flow equations along a horizontal plane passing through the average water surface. This approach is an improvement over the depth-averaged flow models where dispersion terms reflecting vertical effects are neglected. In the model, vertical gradient effects are accounted for through the use of power law for the vertical distribution of the longitudinal velocity; a similar treatment is applied to lateral turbulent shear stresses. The model is capable of computing the dynamic pressure distribution, which in turn is converted to water elevation values. The model, being two dimensional, is computationally efficient and practical to use. The numerical model was successfully verified using experimental data from vertical wall abutments and groins with protrusion ratios (ratio of protrusion length perpendicular to direction of flow to total channel width) of 0.1, 0.2 and 0.3. The results show the occurrence of a high intensity velocity zone close to the upstream abutment nose similar to those observed experimentally. The effects of roughness, depth, and energy slope on the intensity of flow field is investigated and an analytical expression is developed. Numerical experiments indicate that grain roughness affects flow field around the abutment nose by controlling the magnitude of the lateral velocity component and by controlling the lateral extent of the affected zone. Velocity amplification at the abutment nose is found to be mainly related to the protrusion ratio and to the friction factor, and can be up to 1.75 times the approach velocities for protrusion ratios of 0.3. For a protrusion ratio of 0.3, for a typical range of roughness values the increase in nose velocities due to friction factor alone was found to be up to 20 percent.

Molinas, A.; Hafez, Y. I.

2000-07-01

71

CALIPSO Lidar Ratio Retrieval Over the Ocean  

NASA Technical Reports Server (NTRS)

We are demonstrating on a few cases the capability of CALIPSO to retrieve the 532 nm lidar ratio over the ocean when CloudSat surface scattering cross section is used as a constraint. We are presenting the algorithm used and comparisons with the column lidar ratio retrieved by the NASA airborne high spectral resolution lidar. For the three cases presented here, the agreement is fairly good. The average CALIPSO 532 nm column lidar ratio bias is 13.7% relative to HSRL, and the relative standard deviation is 13.6%. Considering the natural variability of aerosol microphysical properties, this level of accuracy is significant since the lidar ratio is a good indicator of aerosol types. We are discussing dependencies of the accuracy of retrieved aerosol lidar ratio on atmospheric aerosol homogeneity, lidar signal to noise ratio, and errors in the optical depth retrievals. We are obtaining the best result (bias 7% and standard deviation around 6%) for a nighttime case with a relatively constant lidar ratio (in the vertical) indicative of homogeneous aerosol type

Josset, Damien B.; Rogers, Raymond R.; Pelon, Jacques; Hu, Yongxiang; Liu, Zhaoyan; Omar, Ali H.; Zhai, Peng-Wang

2011-01-01

72

CALIPSO lidar ratio retrieval over the ocean.  

PubMed

We are demonstrating on a few cases the capability of CALIPSO to retrieve the 532 nm lidar ratio over the ocean when CloudSat surface scattering cross section is used as a constraint. We are presenting the algorithm used and comparisons with the column lidar ratio retrieved by the NASA airborne high spectral resolution lidar. For the three cases presented here, the agreement is fairly good. The average CALIPSO 532 nm column lidar ratio bias is 13.7% relative to HSRL, and the relative standard deviation is 13.6%. Considering the natural variability of aerosol microphysical properties, this level of accuracy is significant since the lidar ratio is a good indicator of aerosol types. We are discussing dependencies of the accuracy of retrieved aerosol lidar ratio on atmospheric aerosol homogeneity, lidar signal to noise ratio, and errors in the optical depth retrievals. We are obtaining the best result (bias 7% and standard deviation around 6%) for a nighttime case with a relatively constant lidar ratio (in the vertical) indicative of homogeneous aerosol type. PMID:21935239

Josset, Damien; Rogers, Raymond; Pelon, Jacques; Hu, Yongxiang; Liu, Zhaoyan; Omar, Ali; Zhai, Peng-Wang

2011-09-12

73

Vertically scanned laser sheet microscopy.  

PubMed

Laser sheet microscopy is a widely used imaging technique for imaging the three-dimensional distribution of a fluorescence signal in fixed tissue or small organisms. In laser sheet microscopy, the stripe artifacts caused by high absorption or high scattering structures are very common, greatly affecting image quality. To solve this problem, we report here a two-step procedure which consists of continuously acquiring laser sheet images while vertically displacing the sample, and then using the variational stationary noise remover (VSNR) method to further reduce the remaining stripes. Images from a cleared murine colon acquired with a vertical scan are compared with common stitching procedures demonstrating that vertically scanned light sheet microscopy greatly improves the performance of current light sheet microscopy approaches without the need for complex changes to the imaging setup and allows imaging of elongated samples, extending the field of view in the vertical direction. PMID:25271539

Dong, Di; Arranz, Alicia; Zhu, Shouping; Yang, Yujie; Shi, Liangliang; Wang, Jun; Shen, Chen; Tian, Jie; Ripoll, Jorge

2014-10-01

74

Baseball Lab (Ratios)  

NSDL National Science Digital Library

Using batting averages, students will create ratios and convert them to rounded decimals (3 places). In addition, they will take decimals and determine several possible equivalent ratios. Then using the relationship that batting average = hits/at bats, the students can use proportions or equations to find either the number of hits or the number of at bats for a given situations.

2010-01-01

75

Transformer ratio enhancement experiment  

Microsoft Academic Search

Recently, a multibunch scheme for efficient acceleration based on dielectric wakefield accelerator technology was outlined in ref.[1]. In this paper we present an experimental program for the design, development and demonstration of an Enhanced Transformer Ratio Dielectric Wakefield Accelerator (ETR-DWA). The principal goal is to increase the transformer ratio R, the parameter that characterizes the energy transfer efficiency from the

A. Kanareykin; Wei Gai; J. G. Power; E. Nenasheva; A. Altmark

2003-01-01

76

On savings ratio  

Microsoft Academic Search

This paper explores the factors that affect saving and consumption behaviours, in a context where some believe that the high savings ratio of the East Asia and oil-producing countries is one major cause for the global imbalances and the crisis. The paper elaborates on the factors behind the high savings ratios in East Asia and oil producing countries and low

Z. Xiaochuan

2011-01-01

77

Likelihood Ratio Tests  

NSDL National Science Digital Library

This page, created by Kyle Siegrist of the University of Alabama - Huntsville, introduces likelihood ratio tests by giving the Neyman-Pearson lemma and several examples. The examples include a gamma model, a binomial model, and a nonparametric model. The page concludes with a definition of the generalized likelihood ratio test.

Siegrist, Kyle

2009-01-12

78

Horizontal Inequity and Vertical Redistribution  

Microsoft Academic Search

Inequality of post-tax income among pre-tax equals is evaluated andaggregated to form a global index of horizontal inequity in the income tax.The vertical action of the tax is captured by its inequality effect on averagebetween groups of pre-tax equals. Putting the two together, horizontalinequity measures loss of vertical performance. The identification problem,which has previously been thought insuperable, is addressed by

Peter J. Lambert; Xavier Ramos

1997-01-01

79

Numerical study of natural convection in a vertical porous annulus with discrete heating  

E-print Network

Numerical study of natural convection in a vertical porous annulus with discrete heating M. Sankar online 20 December 2010 Keywords: Natural convection Annulus Discrete heating Porous medium Radii ratio Brinkman-extended Darcy model a b s t r a c t In this paper natural convection flows in a vertical annulus

Lopez, John M.

80

Development of vertical and tapered via etch for 3D through wafer interconnect technology  

Microsoft Academic Search

Two types of dry silicon etch techniques are developed to cover two different areas of demand for interconnect technology: one for high aspect ratio (AR) vertical vias and one for tapered vias. Various sizes of vertical vias and trenches with diameters\\/widths ranging from 1-100 mum with an AR up to 50 are realized using Bosch deep reactive ion etch (DRIE)

Deniz Sabuncuoglu Tezcan; K. De Munck; N. Pham; O. Luhn; A. Aarts; P. De Moor; K. Baert; C. Van Hoof

2006-01-01

81

New correlations for mixed turbulent natural and forced convection heat transfer in vertical tubes  

Microsoft Academic Search

This work deals with mixed natural and forced turbulent convection heat transfer in vertical tubes. It summarizes the experimental results available in literature for both aiding and opposing flow conditions and presents own experimental results that concentrated on the influence of length-to-diameter ratio and of heat and mass flux directions on heat transfer in vertical tubes. Finally, it presents two

T. Aicher; H. Martin

1997-01-01

82

46 CFR 108.160 - Vertical ladders.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Vertical ladders. 108.160 Section 108.160 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... Construction and Arrangement Means of Escape § 108.160 Vertical ladders. (a) Each vertical...

2010-10-01

83

Vertical vibration and shape oscillation of acoustically levitated water drops  

NASA Astrophysics Data System (ADS)

We present the vertical harmonic vibration of levitated water drops within ultrasound field. The restoring force to maintain such a vibration mode is provided by the resultant force of acoustic radiation force and drop gravity. Experiments reveal that the vibration frequency increases with the aspect ratio for drops with the same volume, which agrees with the theoretical prediction for those cases of nearly equiaxed drops. During the vertical vibration, the floating drops undergo the second order shape oscillation. The shape oscillation frequency is determined to be twice the vibration frequency.

Geng, D. L.; Xie, W. J.; Yan, N.; Wei, B.

2014-09-01

84

Common ratio using delay  

Microsoft Academic Search

We present an experiment in which we add a common delay in a choice between two risky prospects. The results show that delay\\u000a produces the same change in preferences as in the well-documented common ratio effect in risky lotteries. The added common\\u000a delay acts as if the probabilities were divided by some common ratio. Moreover, we show that there is

Manel Baucells; Franz H. Heukamp

2010-01-01

85

Isotope Ratio Mass Spectrometry.  

PubMed

Isotope Ratio Mass Spectrometry (IRMS) is a specialized technique used to provide information about the geographic, chemical, and biological origins of substances. The ability to determine the source of an organic substance stems from the relative isotopic abundances of the elements which comprise the material. Because the isotope ratios of elements such as carbon, hydrogen, oxygen, sulfur, and nitrogen can become locally enriched or depleted through a variety of kinetic and thermodynamic factors, measurement of the isotope ratios can be used to differentiate between samples which otherwise share identical chemical compositions. Several sample introduction methods are now available for commercial isotope ratio mass spectrometers. Combustion is most commonly used for bulk isotopic analysis, whereas gas and liquid chromatography are predominately used for the real-time isotopic analysis of specific compounds within a mixture. Here, highlights of advances in instrumentation and applications within the last three years are provided to illustrate the impact of this rapidly growing area of research. Some prominent new applications include authenticating organic food produce, ascertaining whether or not African elephants are guilty of night-time raids on farmers' crops, and linking forensic drug and soil samples from a crime scene to a suspected point of origin. For the sake of brevity, we focus this Minireview on the isotope ratio measurements of lighter-elements common to organic sources; we do not cover the equally important field of inorganic isotope ratio mass spectrometry. PMID:19173039

Muccio, Zeland; Jackson, Glen P

2009-02-01

86

Vertical saccades in dyslexic children.  

PubMed

Vertical saccades have never been studied in dyslexic children. We examined vertical visually guided saccades in fifty-six dyslexic children (mean age: 10.5±2.56 years old) and fifty-six age matched non dyslexic children (mean age: 10.3±1.74 years old). Binocular eye movements were recorded using an infrared video-oculography system (mobileEBT(®), e(ye)BRAIN). Dyslexic children showed significantly longer latency than the non dyslexic group, also the occurrence of anticipatory and express saccades was more important in dyslexic than in non dyslexic children. The gain and the mean velocity values were significantly smaller in dyslexic than in non dyslexic children. Finally, the up-down asymmetry reported in normal population for the gain and the velocity of vertical saccades was observed in dyslexic children and interestingly, dyslexic children also reported an up-down asymmetry for the mean latency. Taken together all these findings suggested impairment in cortical areas responsible of vertical saccades performance and also at peripheral level of the extra-ocular oblique muscles; moreover, a visuo-attentionnal bias could explain the up-down asymmetry reported for the vertical saccade triggering. PMID:25151607

Tiadi, Aimé; Seassau, Magali; Bui-Quoc, Emmanuel; Gerard, Christophe-Loïc; Bucci, Maria Pia

2014-11-01

87

Seismic Behaviour of Vertical Mass Isolated Structures  

SciTech Connect

In this paper, the seismic behaviour of vertical mass isolated structures against the earthquake is studied. These structures are assumed to be consisted of two subsystems. Mass subsystem possesses low lateral stiffness but carries the major part of mass of the system. Stiffness subsystem, however, controls the deformation of the mass subsystem and attributes with much higher stiffness. The isolator layer is, therefore, located in between the mass and the stiffness subsystems and assumed to be a viscous damper layer. The analytical model used for this investigation is a dual mass-spring model which is an extended form of the three element Maxwell model. In this study, the ability of mass isolation techniques in reducing earthquake effects on buildings with two approaches, parametric and numerical approaches, is shown. In the parametric approach, by definition an isolation factor for structure and determination the dynamic characteristics of system, the relative optimum value of the isolator damping coefficient is obtained. The results provide an insight on role of relative stiffness and mass ratio of the two subsystems. Finally, in the numerical approach, the spectral responses of these structures due to the earthquake are investigated. The results show a noticeable decrease in earthquake input force to vertical mass isolated structures in comparison with non-isolated structures.

Nekooei, M.; Ziyaeifar, M. [Structural Engineering Research Centre, International Institute of Earthquake Engineering and Seismology (IIEES), P.O. Box 19395-3913, Tehran (Iran, Islamic Republic of)

2008-07-08

88

Progress on relationships between horizontal and vertical dust flux: Mathematical, empirical and risk-based perspectives  

NASA Astrophysics Data System (ADS)

Aeolian processes driving sediment flux and corresponding erosion are inherently 3-dimensional, but are primarily studied either with respect to the horizontal flux component, or to a lesser extent the vertical component. Understanding the relationship between horizontal flux and the vertical component of sediment and dust is critical to predicting fundamental processes such as erosion, and to assessing human and environmental risks associated with contaminated sediment and dust. Multiple mathematical approaches to calculate vertical flux of dust exist but are limited in their ability to predict vertical flux across a wide variety of landscapes and soil conditions. To address these issues, here we explore the relationship between horizontal and vertical fluxes from three perspectives: mathematical, based on existing equations; empirical, based on existing and new data; and risk-based, based on translating the former two into a risk context. Mathematical derivations suggest, depending on the approach, the two components could either be a constant ratio or that the vertical flux could be more dependent on the shear stress and particle size than horizontal flux. Empirical data highlight a wide range of ratios, varying by more than two orders of magnitude, though the ratios can be relatively similar within a given site and set of conditions. Risk-based assessment indicates the vertical flux component is relatively important in dose calculations, and consequently further improvement in mathematical and empirical relationships is needed. Collectively, these three perspectives expand insights on horizontal and vertical sediment fluxes and could aide future risk assessment from dust contaminants.

Whicker, Jeffrey J.; Breshears, David D.; Field, Jason P.

2014-09-01

89

Measurements of vertical bar Vcb vertical bar and vertical bar Vub vertical bar at BaBar  

SciTech Connect

We report results from the BABAR Collaboration on the semileptonic B decays, highlighting the measurements of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix elements Vub and Vcb. We describe the techniques used to obtain the matrix element |Vcb| using the measurement of the inclusive B {yields} Xclv process and a large sample of exclusive B {yields} D*lv decays. The vertical bar Vub vertical bar matrix elements has been measured studying different kinematic variables of the B {yields} Xulv process, and also with the exclusive reconstruction of B {yields} {pi}({rho})lv decays.

Rotondo, M. [Dipartimento di Fisica Galileo Galilei, Via Marzolo 8, Padova 35131 (Italy)

2005-10-12

90

Vertical motion simulator familiarization guide  

NASA Technical Reports Server (NTRS)

The Vertical Motion Simulator Familiarization Guide provides a synoptic description of the Vertical Motion Simulator (VMS) and descriptions of the various simulation components and systems. The intended audience is the community of scientists and engineers who employ the VMS for research and development. The concept of a research simulator system is introduced and the building block nature of the VMS is emphasized. Individual sections describe all the hardware elements in terms of general properties and capabilities. Also included are an example of a typical VMS simulation which graphically illustrates the composition of the system and shows the signal flow among the elements and a glossary of specialized terms, abbreviations, and acronyms.

Danek, George L.

1993-01-01

91

Waves, circulation and vertical dependence  

NASA Astrophysics Data System (ADS)

Longuet-Higgins and Stewart (J Fluid Mech 13:481-504, 1962; Deep-Sea Res 11:529-562, 1964) and later Phillips (1977) introduced the problem of waves incident on a beach, from deep to shallow water. From the wave energy equation and the vertically integrated continuity equation, they inferred velocities to be Stokes drift plus a return current so that the vertical integral of the combined velocities was nil. As a consequence, it can be shown that velocities of the order of Stokes drift rendered the advective term in the momentum equation negligible resulting in a simple balance between the horizontal gradients of the vertically integrated elevation and wave radiation stress terms; the latter was first derived by Longuet-Higgins and Stewart. Mellor (J Phys Oceanogr 33:1978-1989, 2003a), noting that vertically integrated continuity and momentum equations were not able to deal with three-dimensional numerical or analytical ocean models, derived a vertically dependent theory of wave-circulation interaction. It has since been partially revised and the revisions are reviewed here. The theory is comprised of the conventional, three-dimensional, continuity and momentum equations plus a vertically distributed, wave radiation stress term. When applied to the problem of waves incident on a beach with essentially zero turbulence momentum mixing, velocities are very large and the simple balance between elevation and radiation stress gradients no longer prevails. However, when turbulence mixing is reinstated, the vertically dependent radiation stresses produce vertical velocity gradients which then produce turbulent mixing; as a consequence, velocities are reduced, but are still larger by an order of magnitude compared to Stokes drift. Nevertheless, the velocity reduction is sufficient so that elevation set-down obtained from a balance between elevation gradient and radiation stress gradients is nearly coincident with that obtained by the aforementioned papers. This paper includes four appendices. The first appendix demonstrates the numerical process by which Stokes drift is excluded from the turbulence stress parameterization in the momentum equation. A second appendix determines a bottom slope criterion for the application of linear wave relations to the derivation of the wave radiation stress. The third appendix explores the possibility of generalizing results by non-dimensionalization. The final appendix applies the basic theory to a problem introduced by Bennis and Ardhuin (J Phys Oceanogr 41:2008-2012, 2011).

Mellor, George

2013-04-01

92

New "Golden" Ratios for Facial Beauty  

PubMed Central

In four experiments, we tested the existence of an ideal facial feature arrangement that could optimize the attractiveness of any face given its facial features. Participants made paired comparisons of attractiveness between faces with identical facial features but different eye-mouth distances and different interocular distances. We found that although different faces have varying attractiveness, individual attractiveness is optimized when the face’s vertical distance between the eyes and the mouth is approximately 36% of its length, and the horizontal distance between the eyes is approximately 46% of the face’s width. These “new” golden ratios match those of an average face. PMID:19896961

Pallett, Pamela M.; Link, Stephen; Lee, Kang

2009-01-01

93

The Golden Ratio  

NSDL National Science Digital Library

This Web site provides a basic introduction to one of the most amazing discoveries in mathematics: the Golden Ratio. Created by David L. Narain, this site offers a particularly engaging way to bring together math and the natural sciences in the classroom. Seven straightforward activities have students construct a golden rectangle and spiral, and also explore the Golden Ratio in nature and in other contexts. The site also includes a quiz; answers are not provided, though. The activities are designed for 9th and 10th graders, but would also be appropriate for middle school students.

Narain, David L.

2001-01-01

94

7, 1275112779, 2007 Vertical distribution  

E-print Network

boundary layer and vertical distribution of pollutants are discussed in terms15 of the energy balance. In an urban area there are many buildings, which cause large inhomogeneities in the energy and wind profiles Center for the Energy and the Environment (MCE2), La Jolla, CA, USA 2 Department of Earth, Atmospheric

Boyer, Edmond

95

Wideband Fractal Vertical Patch Antenna  

Microsoft Academic Search

A wideband vertical patch antenna (VPA) is depicted, which is devised from fractal antenna technology. By using a dual-Koch loop structure, a wideband VPA with 42% bandwidth and 8 dBi gain at the center frequency is designed and tested. Symmetrical broadside patterns are obtained at the passband.

T. P. Wong; Carmen K. L. Lau; Kwai-Man Luk; Kai-Fong Lee

2007-01-01

96

Insulated vertical antennas above ground  

Microsoft Academic Search

A fast efficient method is proposed to solve the problem of a vertical dielectric-coated antenna located in free space above ground. The solution is a moment method solution. The influence of lossy ground is taken into account via equivalent images due to Popovic, and the currents of images are expressed by the source current. The dielectric coating is modeled by

Xianshan Li; Khalil El Khamlichi Drissi; Françoise Paladian

2004-01-01

97

6, 72077233, 2006 Vertical distribution  

E-print Network

cloud sides. Inversion of measurements from the cloud sides requires rigorous understanding of10 the 3 cloud fields generated by a simple stochastic cloud model with the prescribed vertically resolved values of the droplet effective radius. The retrieval algorithm is based on the Bayesian theorem that com

Paris-Sud XI, Université de

98

Vertical axis wind turbine development  

Microsoft Academic Search

Theoretical and experimental research accomplished in evaluating an innovative concept for vertical axis wind turbines (VAWT) is described. The concept is that of using straight blades composed of circulation controlled airfoil sections. The theoretical analysis was developed to determine the unsteady lift and moment characteristics of multiple-blade cross-flow wind turbines. To determine the drag data needed as input to the

R. E. Walters; J. B. Fanucci; P. W. Hill; P. G. Migliore

1979-01-01

99

The Likelihood Ratio Test  

NSDL National Science Digital Library

This module, created by Don Johnson of Rice University, provides an explanation and an example of the likelihood ratio test. Topics include: decision regions, Bayes' decision criterion, Bayes' cost, and likelihood function. The site is enhanced by Johnson's use of graphic and numerical demonstrations to better explain his points. Additionally, a PDF attachment providing an in-depth explanation is also featured.

Johnson, Don

2009-01-08

100

Digit ratio in birds.  

PubMed

The Homeobox (Hox) genes direct the development of tetrapod digits. The expression of Hox genes may be influenced by endogenous sex steroids during development. Manning (Digit ratio. New Brunswick, NJ: Rutgers University Press, 2002) predicted that the ratio between the lengths of digits 2 (2D) and 4 (4D) should be sexually dimorphic because prenatal exposure to estrogens and androgens positively influence the lengths of 2D and 4D, respectively. We measured digits and other morphological traits of birds from three orders (Passeriformes, house sparrow, Passer domesticus; tree swallow, Tachycineta bicolor; Pscittaciformes, budgerigar, Melopsittacus undulates; Galliformes, chicken, Gallus domesticus) to test this prediction. None were sexually dimorphic for 2D:4D and there were no associations between 2D:4D and other sexually dimorphic traits. When we pooled data from all four species after we averaged right and left side digits from each individual and z-transformed the resulting digit ratios, we found that males had significantly larger 2D:4D than did females. Tetrapods appear to be sexually dimorphic for 2D:4D with 2D:4D larger in males as in some birds and reptiles and 2D:4D smaller in males as in some mammals. The differences between the reptile and mammal lineages in the directionality of 2D:4D may be related to the differences between them in chromosomal sex determination. We suggest that (a) natural selection for a perching foot in the first birds may have overridden the effects of hormones on the development of digit ratio in this group of vertebrates and (b) caution be used in making inferences about prenatal exposure to hormones and digit ratio in birds. PMID:18833568

Lombardo, Michael P; Thorpe, Patrick A; Brown, Barbara M; Sian, Katie

2008-12-01

101

Displacementlength scaling in three dimensions: the importance of aspect ratio and application to deformation bands  

E-print Network

and vertical sections due to differences in fracture dimension (length vs. height) and end-zone length, with the vertical (z, `thickness') dimension included only implicitly (Timoshenko and Goodier, 1970, pp. 15±17; TadaDisplacement±length scaling in three dimensions: the importance of aspect ratio and application

Fossen, Haakon

102

Dual-band and CP vertical patch antennas  

Microsoft Academic Search

New geometries are proposed for the newly invented vertical patch antenna (VPA) for dual band operation and circular polarization generation respectively. The dual-band VPA maintains the advantages of the singleband VPA, such as small size, wideband and simple structure. For the circularly polarized (CP) VPA, it exhibits a gain of 8dBi over 3dB axial ratio bandwidth of 4%

Ka-lam Lau; Hang Wong; Chi-lun Mak; Kwai-man Luk; Kai-Fong Lee

2005-01-01

103

What's My Ratio?  

NSDL National Science Digital Library

In this activity, students use linear measurement and calculators to investigate proportionality and determine the constant ratio between similar figures. In it, students draw a figure on centimeter graph paper, increase or decrease the size, and predict the dimensions. Then students compare the ratio of two pictures by measuring, recording their data, and discussing their findings to draw conclusions. Suggested guidelines for instruction and classroom discussion are included, as well as data collection worksheets for students, and centimeter graph paper to print. The lesson may be introduced by reading appropriate sections from "GoosebumpsâMonster Blood III" (Chapters 15 and 16) by R.L. Stine, or "The Shrinking of Treehorn" by F. Heide.

2003-01-01

104

Displacement and Velocity Ratios  

NSDL National Science Digital Library

This interactive presentation, created by James Bourassa and John Rosz for the Electromechanical Digital Library, discusses displacement and velocity ratios. Bourassa and Rosz begin by providing detailed definitions of both topics and then provide mathematical examples of each. Once this basic explanation is complete, the authors allow students to practice these theories in a set of self-correcting quiz questions. Bourassa and Rosz explain each using helpful interactive flash animations. These are not only useful in explanation, but they allow the student to more fully engage with the topic. Overall, this is a nice introduction to the physical and mathematical concepts of displacement and velocity ratios. This could be a valuable learning resource in everything from a physics to a technical education classroom.

Bourassa, James; Rosz, John

2011-04-05

105

Ratio Word Problems  

NSDL National Science Digital Library

This lesson begins with a word problem in which students must figure how much money Erica and Tim each earn when they split $480 by a ratio of 5:3. After the problem, students watch a video in which the problem is solved using division and multiplication and again using fractions. Students then click the Try It button to complete a problem on their own. There are also embedded tools, a calculator and scratchpad, for students to use as they solve.

2006-01-01

106

Ratios and Proportions  

NSDL National Science Digital Library

This interactive slideshow explains the notion of ratios and proportions, how to write the, and how to find them. There are practice problems which walk visitors through each step of the process, including reducing answers to simplest terms, in which students are asked to calculate the rate of grass seed coverage per square foot and find the miles per gallon fuel use of a car. The lesson continues on to introduce proportion and work through practice problems in the same fashion.

Jensen, Douglas; Reed, Allen

2005-01-01

107

Measurement of ? branching ratios  

NASA Astrophysics Data System (ADS)

We have measured the branching ratios for several ? decay modes. We use e+e--->?+?- events accumulated with the TPC/Two-Gamma facility at the SLAC e+e- storage ring PEP. The data correspond to an integrated luminosity of 77 pb-1 at a center-of-mass energy of 29 GeV. The one- and three-charged-particle inclusive branching ratios of the ? decay are measured to be B1=(84.7+/-1.0)% and B3=(15.1+/-1.0)%, where B1+B3 is constrained to be 99.85%. The branching ratios of the two leptonic decay modes are B(?--->e- ?¯e??)=(18.4+/-1.6)% and B(?--->?- ?¯???)=(17.7+/-1.4)%. If we then assume lepton universality, we obtain B(?--->e- ?¯e??)=(18.3+/-0.9)% and B(?--->?- ?¯???)=(17.8+/-0.9)%. We measure the Cabibbo-allowed semihadronic decay mode B(?--->?-+neutral particles)=(47.0+/-1.5)%, and the Cabibbo-suppressed ? decay mode B(?--->K-+neutral particles)=(1.6+/-0.4)%. By looking for associated photons, we find B(?--->K-?0+neutral particles) to be (1.2+/-0.6)%. Using the channel K*--->KOS?+?-, we find B(?--->K*-(892)+neutral particles)=(1.4+/-0.9)%. The quoted errors are the combined statistical and systematic errors.

Aihara, H.; Alston-Garnjost, M.; Avery, R. E.; Bakken, J. A.; Barbaro-Galtieri, A.; Barker, A. R.; Barnes, A. V.; Barnett, B. A.; Barnett, B. A.; Bauer, D. A.; Bengtsson, H.-U.; Bintinger, D. L.; Bobbink, G. J.; Bolognese, T. S.; Bross, A. D.; Buchanan, C. D.; Buijs, A.; Caldwell, D. O.; Chien, C.-Y.; Clark, A. R.; Cowan, G. D.; Crane, D. A.; Dahl, O. I.; Derby, K. A.; Eastman, J. J.; Edberg, T. K.; Eberhard, P. H.; Eisner, A. M.; Enomoto, R.; Erné, F. C.; Fujii, T.; Gary, J. W.; Gorn, W.; Hauptman, J. M.; Hofmann, W.; Huth, J. E.; Hylen, J.; Kamae, T.; Kaye, H. S.; Kees, K. H.; Kenney, R. W.; Kerth, L. T.; Ko, Winston; Koda, R. I.; Kofler, R. R.; Kwong, K. K.; Lander, R. L.; Langeveld, W. G.; Layter, J. G.; Linde, F. L.; Lindsey, C. S.; Loken, S. C.; Lu, A.; Lu, X.-Q.; Lynch, G. R.; Madansky, L.; Madaras, R. J.; Maeshima, K.; Magnuson, B. D.; Marx, J. N.; Masek, G. E.; Mathis, L. G.; Matthews, J. A.; Maxfield, S. J.; Melnikoff, S. O.; Miller, E. S.; Moses, W.; McNeil, R. R.; Nemethy, P.; Nygren, D. R.; Oddone, P. J.; Paar, H. P.; Park, D. A.; Park, S. K.; Pellett, D. E.; Pevsner, A.; Pripstein, M.; Ronan, M. T.; Ross, R. R.; Rouse, F. R.; Schwitkis, K. A.; Sens, J. C.; Shapiro, G.; Shapiro, M. D.; Shen, B. C.; Slater, W. E.; Smith, J. R.; Steinman, J. S.; Stevenson, M. L.; Stork, D. H.; Strauss, M. G.; Sullivan, M. K.; Takahashi, T.; Thompson, J. R.; Toge, N.; Toutounchi, S.; van Tyen, R.; van Uitert, B.; Vandalen, G. J.; van Daalen Wetters, R. F.; Vernon, W.; Wagner, W.; Wang, E. M.; Wang, Y. X.; Wayne, M. R.; Wenzel, W. A.; White, J. T.; Williams, M. C.; Wolf, Z. R.; Yamamoto, H.; Yellin, S. J.; Zeitlin, C.; Zhang, W.-M.

1987-03-01

108

Kinematic Fitting of Detached Vertices  

SciTech Connect

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.

Paul Mattione

2007-05-01

109

Vertically Integrated Circuits at Fermilab  

SciTech Connect

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.

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

2009-01-01

110

5-Foot Vertical Wind Tunnel  

NASA Technical Reports Server (NTRS)

Construction of 5-Foot Vertical Wind Tunnel. The 5-Foot Vertical Wind Tunnel was built to study spinning characteristics of aircraft. It was an open throat tunnel capable of a maximum speed of 80 mph. NACA engineer Charles H. Zimmerman designed the tunnel starting in 1928. Construction was completed in December 1929. It was one of two tunnels which replaced the original Atmospheric Wind Tunnel (The other was the 7x10-Foot Wind Tunnel.). In NACA TR 387 (p. 499), Carl Wenzinger and Thomas Harris report that 'the tunnel passages are constructed of 1/8-inch sheet iron, stiffened with angle iron and bolted together at the corners. The over-all dimensions are: Height 31 feet 2 inches; length, 20 feet 3 inches; width, 10 feet 3 inches.' The tunnel was partially constructed in the Langley hanger as indicated by the aircraft in the background. Published in NACA TR 387, 'The Vertical Wind Tunnel of the National Advisory Committee for Aeronautics,' by Carl J. Wenzinger and Thomas A. Harris, 1931.

1930-01-01

111

Ratios, Proportions, Similarity  

NSDL National Science Digital Library

This is a set of four, one-page problems about the size of planets compared to earth. Learners may use ratios to compare planets within our solar system or those outside of our solar system with the earth. Options are presented so that students may learn about the MESSENGER mission to Mercury through a NASA press release or by viewing a NASA eClips video [6 min.]. This activity is part of the Space Math multi-media modules that integrate NASA press releases, NASA archival video, and mathematics problems targeted at specific math standards commonly encountered in middle school.

112

Vertical Integration and Technology: Theory and Evidence  

E-print Network

We study the determinants of vertical integration. We first derive a number of predictions regarding the relationship between technology intensity and vertical integration from a simple incomplete contracts model. Then, ...

Acemoglu, Daron

113

Vertical silicon nanowire arrays for gas sensing  

E-print Network

The goal of this research was to fabricate and characterize vertically aligned silicon nanowire gas sensors. Silicon nanowires are very attractive for gas sensing applications and vertically aligned silicon nanowires are ...

Zhao, Hangbo

2014-01-01

114

Ratios For All Occasions  

NSDL National Science Digital Library

This resource guide from the Middle School Portal 2 project, written specifically for teachers, provides links to exemplary resources including background information, lessons, career information, and related national science education standards.A central theme in the middle school mathematics curriculum, proportional reasoning is based on making sense of ratios in a variety of contexts. The resources chosen for this unit provide practice in solving problems, often informally, in the format of games, hands-on modeling, mapmaking, and questions selected for their interest for students. As students work through the activities, they will exercise reasoning about basic proportions as ell as further develop their knowledge of the relationship between fractions and percents.The section titled Background Resources for Teachers contains links to workshop sessions, developed for teachers, on the mathematical content of the unit. Ratios in Childrens Books identifies three picture books that entertain while they explore scale and proportion. In the final section, we look at the coverage of proportionality at the iddle level in the NCTM Principles and Standards for School Mathematics.

Herrera, Terese

2006-06-01

115

Wideband Circularly Polarized Vertical Patch Antenna  

Microsoft Academic Search

A compact circularly polarized (CP) vertical patch antenna is presented that employs a microstrip to slot-line transition for a wideband operation. The antenna is composed of two vertical patches, which are shaped as helix to obtain a broadband CP performance. The loop structure and the vertical overlap configuration lead to significant size reduction as much as 48% when compared to

Ze-Hai Wu; Edward Kai-Ning Yung

2008-01-01

116

Vertical Lift - Not Just For Terrestrial Flight  

NASA Technical Reports Server (NTRS)

Autonomous vertical lift vehicles hold considerable potential for supporting planetary science and exploration missions. This paper discusses several technical aspects of vertical lift planetary aerial vehicles in general, and specifically addresses technical challenges and work to date examining notional vertical lift vehicles for Mars, Titan, and Venus exploration.

Young, Larry A

2000-01-01

117

Peak power ratio generator  

DOEpatents

A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

Moyer, Robert D. (Albuquerque, NM)

1985-01-01

118

Ratio and Proportion  

NSDL National Science Digital Library

This interactive Flash applet helps students explore concepts of ratio and proportion. It displays two containers, each with its own tap that can be set to deliver different-colored liquids in units of 1 to 10. A main tap can be set to deliver multiples of the amounts on the left- and right-hand taps. Proportion can be modelled using the drain container, which receives whatever is in the left- and right-hand containers. Users can choose the capacity of the containers, whether to hide or show the scales, and the size and visibility of the drain container. Clicking on the info button allows users to mouse over items to learn about them. This applet lends itself well for use with an interactive white board. A pdf guide to this collection of teaching applets is cataloged separately.

2006-01-01

119

Trace ratio problem revisited.  

PubMed

Dimensionality reduction is an important issue in many machine learning and pattern recognition applications, and the trace ratio (TR) problem is an optimization problem involved in many dimensionality reduction algorithms. Conventionally, the solution is approximated via generalized eigenvalue decomposition due to the difficulty of the original problem. However, prior works have indicated that it is more reasonable to solve it directly than via the conventional way. In this brief, we propose a theoretical overview of the global optimum solution to the TR problem via the equivalent trace difference problem. Eigenvalue perturbation theory is introduced to derive an efficient algorithm based on the Newton-Raphson method. Theoretical issues on the convergence and efficiency of our algorithm compared with prior literature are proposed, and are further supported by extensive empirical results. PMID:19304481

Jia, Yangqing; Nie, Feiping; Zhang, Changshui

2009-04-01

120

Neighbourly polytopes with few vertices  

SciTech Connect

A family of neighbourly polytopes in R{sup 2d} with N=2d+4 vertices is constructed. All polytopes in the family have a planar Gale diagram of a special type, namely, with exactly d+3 black points in convex position. These Gale diagrams are parametrized by 3-trees (trees with a certain additional structure). For all polytopes in the family, the number of faces of dimension m containing a given vertex A depends only on d and m. Bibliography: 7 titles.

Devyatov, Rostislav A [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)

2011-10-31

121

Investigations on miniaturized endfire vertically polarized quasi-fractal log-periodic zigzag antenna  

Microsoft Academic Search

This paper presents the investigations on a miniaturized vertically polarized traveling wave antenna for operation in the high frequency band (3-6 MHz), with a specific requirement of keeping its height near 1\\/8th of a wavelength. The antenna is desired to have a good endfire gain and front to back ratio, and small radiation levels in the vertical direction at broadside

Satish K. Sharma; Lotfollah Shafai

2004-01-01

122

Entropy generation in flow field subjected to a porous block in a vertical channel  

Microsoft Academic Search

Entropy generation in the flow field subjected to a porous block situated in a vertical channel is examined. The effects of\\u000a channel inlet port height (vertical height between channel inlet port and the block center), porosity, and block aspect ratio\\u000a on the entropy generation rate due to fluid friction and heat transfer in the fluid are examined. The governing equations

S. Z. Shuja; Bekir Sami Yilbas; A. Jamal

2008-01-01

123

A comparison of 1920 MHz diversity gain using horizontally and vertically spaced antenna elements  

Microsoft Academic Search

Diversity gain for both a horizontal and a vertical three-element receiving array coupling to a 1920 MHz mobile transmitter in a suburban area is investigated. Various combining techniques are considered (selection diversity, equal gain, maximal ratio). The narrow band (19.6 kHz) diversity gain is greater for the horizontal array than for the vertical array (an average of 10.4 dB vs.

P. Wilson; P. Papazian; M. Cotton; Y. Lo

1999-01-01

124

Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing  

E-print Network

The ocean's role in regulating atmospheric carbon dioxide on glacial-interglacial timescales remains an unresolved issue in paleoclimatology. Reduced mixing between deep water masses may have aided oceanic storage of ...

Ferrari, Raffaele

125

Determination of horizontal-to-vertical hydraulic conductivity ratios from seepage measurements on lake beds  

Microsoft Academic Search

This paper describes a new method of determining the anisotropy of aquifers contiguous with lakes. The method is based on the observed rate of decline of seepage flux with distance offshore and on the thickness of the aquifer. Deviations from an exponential decline in seepage rate with distance offshore give a measure of aquifer heterogeneity and, consequently, an estimate of

V. K. Barwell; David Robert Lee

1981-01-01

126

Natural convection between a vertical cylinder and a surrounding array  

SciTech Connect

The generic situation considered is natural convection between a single heated, vertical cylinder and a surrounding array of cooler vertical cylinders in a triangular pattern. The ratio of the test section temperature to the cooling tube temperature was varied up to 2.6 by adjusting the electrical power. The Rayleigh number, based on test section diameter and air properties evaluated at cooling tube temperature, ranged from 2.9 x 10{sup 4} to 4.6 x 10{sup 5}. Results indicate that the convective heat transfer data could be approximated as Nu{sub D} (T{sub ts}/T{sub ct}){sup 0.14} = 0.156 Ra{sub D}{sup 1/3} in the apparent turbulent region for Ra{sub L} > 1.2 x 10{sup 11.}

McEligot, D.M.; O`Brien, J.E.; Stoots, C.M.; Larson, T.K.; Christenson, W.A.; Mecham, D.C.; Lussie, W.G.

1992-09-01

127

Natural convection between a vertical cylinder and a surrounding array  

SciTech Connect

The generic situation considered is natural convection between a single heated, vertical cylinder and a surrounding array of cooler vertical cylinders in a triangular pattern. The ratio of the test section temperature to the cooling tube temperature was varied up to 2.6 by adjusting the electrical power. The Rayleigh number, based on test section diameter and air properties evaluated at cooling tube temperature, ranged from 2.9 x 10{sup 4} to 4.6 x 10{sup 5}. Results indicate that the convective heat transfer data could be approximated as Nu{sub D} (T{sub ts}/T{sub ct}){sup 0.14} = 0.156 Ra{sub D}{sup 1/3} in the apparent turbulent region for Ra{sub L} > 1.2 x 10{sup 11.}

McEligot, D.M.; O'Brien, J.E.; Stoots, C.M.; Larson, T.K.; Christenson, W.A.; Mecham, D.C.; Lussie, W.G.

1992-01-01

128

Note on the Odds Ratio and the Probability Ratio  

Microsoft Academic Search

This note compares the odds ratio with the probability ratio (relative risk). These quantities arise, for example, in the analysis of educational and social science data by means of logistic regression.

Michael P. Cohen

2000-01-01

129

Vertical structuring of gigantic jets  

NASA Astrophysics Data System (ADS)

Gigantic Jets (GJs) are initiated deep inside the thundercloud as intracloud discharges whose upward-directed leaders manage to escape through the thundercloud top and propagate up to the ionosphere. The speed at which leaders propagate is limited by the air heating of every newly formed leader section, rate of which is slower at upper altitudes in the Earth's atmosphere. Despite the expected deceleration of an upward-directed leader, GJs are observed to accelerate as they approach the ionosphere. In this letter, we discuss the dependence of the leader speed on current density in the leader stem, and we propose a simple time-dynamic model for GJ propagation that includes the effects of the expansion of the streamer zone adjacent to the leader head. We propose that the GJ acceleration is a consequence of its vertical structuring and, therefore, can be used to trace the transition altitude between the leader and streamer zone sections of GJs.

Silva, Caitano L.; Pasko, Victor P.

2013-06-01

130

Controls on vertical mixing of sediment in gravel bed rivers  

NASA Astrophysics Data System (ADS)

Understanding controls on vertical mixing of sediment in gravel bed rivers is important in areas of managing aquatic and riparian habitat, sediment bedload and yield, sediment storage and channel stability, water quality and hydraulic engineering. Sediment tracers disperse in rivers longitudinally downstream and vertically within the channel bed. Few sediment tracer studies focus on vertical mixing of sediment; fewer still focus on its modeling. A deterministic modeling approach to sediment mixing is difficult due to complex physics and limitations in direct measurement. Here we use a simple probability modeling approach to determine primary physical controls on vertical mixing of sediment tracers in three gravel bed rivers: East Creek in British Columbia, and the Allt Dubhaig and Monachyle Burn rivers in Scotland. Burial of sediment tracers is modeled as a binary response with mass, axis dimensions, axis measurement ratios, stone shape and angularity as particle characteristic covariates. Other potential model covariates are particle travel distance and endpoint morphology of tracers. Simple generalized linear models are developed using logistic methods to explore main effects on burial. Primary controls from simple models found to be common across all channels and tracer surveys are then used to develop multivariate logistic models to determine how simultaneous controls and their interactions affect sediment burial. Significant primary controls on vertical mixing were particle size, travel distance and endpoint morphology. Most multivariate models had either one of two significant outcomes with respect to simultaneous control on burial: (1) burial probability given particle size and endpoint morphology (Figure 1), or (2) burial probability given particle size and particle travel distance (not shown).

Voepel, H.; Schumer, R.; Hassan, M. A.

2011-12-01

131

Natural convection in a vertical annulus containing water near the density maximum  

SciTech Connect

Steady natural convection of water near the density extremum in a vertical annulus is studied numerically. Results for flow in annuli with aspect ratio 1 {le} A {le} 8 and varying degrees of curvature are given for 10{sup 3} {le} Ra {le} 10{sup 5}. It is shown that both the density distribution parameter R and the annulus curvature K have a strong effect on the steady flow structure and heat transfer in the annulus. A closed-form solution for the vertical flow in a very tall annulus is compared with numerical results for finite-aspect-ratio annuli.

Lin, D.S.; Nansteel, M.W. (Univ. of Pennsylvania, Philadelphia (USA))

1987-11-01

132

Characteristics of vertical climbing in African apes  

Microsoft Academic Search

The evolution of bipedalism is a key event in the transition from apes to early hominids. Vertical climbing has been proposed\\u000a to be the critical locomotor behaviour preadaptive to habitual bipedalism, although quantitative data about vertical climbing\\u000a in nonhuman primates are scarce. This study focuses on 3D-kinematics of vertical climbing in different hominoid species in\\u000a zoos. Emphasis is laid on

Karin Isler

2002-01-01

133

Strehl ratio and aberration balancing  

Microsoft Academic Search

The relation between the Strehl ratio and the wave-front variance is analyzed from the point of view of aberration balancing. For some given set of aberrations the Strehl ratio is calculated along two different parametric paths in the aberration space: one corresponding to the minimum wave-front variance and the other to the maximum Strehl ratio. The case of the combination

Geiser Martial

1991-01-01

134

Sex ratio dependent dispersal when sex ratios vary between patches.  

PubMed

Female biased sex ratios reduce competition between brothers when mating takes place within local patches. Male dispersal prior to mating is another strategy that reduces competition between brothers. One may thus expect these two traits to co-evolve and this is partially met in that sex ratios becomes less female biased as dispersal increases. However, the evolutionary stable degree of dispersal is unaffected by the sex ratio. The analytical models developed to reach these conclusions ignored variance in sex ratios, since this increases the structural complexity of models. For similar reasons finite clutch sizes are also routinely ignored. To overcome these shortfalls, we developed individual based simulations that allowed us to incorporate realistic clutch sizes and binomial variance in sex ratios between patches. We show that under variable sex ratios, males evolve to more readily disperse away from patches with higher sex ratios than lower sex ratios. We show that, while the dispersal rate is insensitive to the sex ratio when sex ratios are precise, it is affected by the number of males with dispersal decreasing as the number of males decreases. PMID:21893071

Nelson, Ronald M; Greeff, Jaco M

2011-12-01

135

Inequalities and Monotonicity of the Ratio of the Geometric Means of a Positive Arithmetic Sequence with Unit Difference  

ERIC Educational Resources Information Center

For any nonnegative integer "k" and natural numbers "n" and "m," the equations presented in this paper demonstrate the inequalities obtained on the ratio for the geometric means of a positive arithmetic sequence with unit difference, where alpha epsilon [vertical bar]0,1[vertical bar] is a constant. Using the ideas and methods of Chen (2002),…

Qi, Feng

2003-01-01

136

Emission Ratios from SCIAMACHY simultaneous measurements  

NASA Astrophysics Data System (ADS)

The spectra of reflected and backscattered solar radiation as measured by SCIAMACHY in nadir observation mode in the UV/visible/near-infrared/short-wave-infrared spectral region contain information on the vertical columns of numerous air pollutants and therefore provide a large-scale perspective on spacious and uncertain pollution sources like biomass burnings. It will be shown that under a number of reasonable assumptions we can obtain a quantitative charac-teristics of biomass burning emissions in terms of emission ratios (ER) using only the averages of the atmospheric gas columns retrieved from the space-based simultaneous measurements. Considering for example the SCIAMACHY carbon monoxide (CO), taken as a reference car-bon component, together with the SCIAMACHY formaldehyde (HCHO) and nitrogen dioxide (NO2) columns in the scope of a well established emission quantification method we calcu-late the emission ratios, CO/HCHO and CO/NO2, over large biomass burning events in 2004 (established with the help of the AATSR fire counts product). We show that the calculated ER values are in reasonable agreement with the values obtained locally over similar biomass burning events reported in the literature. In addition, we discuss the relatively large values over the boreal forest fires in Alaska and Siberia, where ER values from local measurements were not yet reported.

Khlystova, Iryna; Richter, Andreas; Wittrock, Folkard; Burrows, John P.; Buchwitz, Michael; Bovensmann, Heinrich

137

ITER physics design guidelines at high aspect ratio  

SciTech Connect

The physics requirements for ITER design are formulated in a set of physics design guidelines. These guidelines, established by the ITER Physics Group during the Conceptual Design Activity (CDA, 1988--90), were based on credible extrapolations of the tokamak physics database as assessed during the CDA, and defined a class of tokamak designs (with plasma current I {approximately}20 MA and aspect ratio A {approximately}2.5--3.5) that meet the ITER objectives. Recent US studies have indicated that there may be significant benefits if the ITER-CDA design point is moved from the low aspect ratio, high current baseline (A = 2.79, I = 22 MA) to a high aspect ratio machine at A {approximately}4, I {approximately}15 MA, especially regarding steady-state, technology-testing performance. To adequately assess the physics and technology testing capability of higher aspect ratio design options, several changes are proposed to the original ITER guidelines to reflect the latest (although limited) developments in physics understanding at higher aspect ratios. The critical issues for higher aspect ratio design options are the uncertainty in scaling of confinement with aspect ratio, the variation of vertical stability with elongation and aspect ratio, plasma shaping requirements, ability to control and maintain plasma current and q-profiles for MHD stability (and volt-second consumption), access for current drive, restrictions on field ripple and divertor plate incident angles, etc. 5 refs., 1 tab.

Uckan, N.A.

1991-01-01

138

Introduction Diel vertical migration occurs when plankton  

E-print Network

Introduction Diel vertical migration occurs when plankton migrate vertically in the water column over a 24 h cycle. Zooplankton typically migrate nocturnally, occupying depths near the hypolimnion during the day and moving into the epilimnion during the evening (Haney 1993). Reverse migration

New Hampshire, University of

139

Sewing string tree vertices with ghosts  

E-print Network

It is shown how to sew string vertices with ghosts at tree level in order to produce new tree vertices using the Group Theoretic approach to String Theory. It is then verified the BRST invariance of the sewn vertex and shown that it has the correct ghost number.

L. Sandoval Jr

1999-09-22

140

Sewing string tree vertices using canonical forms  

E-print Network

We effectively sew two vertices with ghosts in order to obtain a third, composite vertex in the most general case of cycling transformations. In order to do this, we separate the vertices into two parts: a bosonic oscillator part and a ghost oscillator part and write them as canonical forms.

Leonidas Sandoval Jr

2001-04-17

141

Evolution of Mutualistic Symbiosis without Vertical Transmission  

Microsoft Academic Search

Mutualistic symbioses are considered to evolve from parasitic relationships. Vertical transmission, defined as the direct transfer of infection from a parent organism to its progeny, has been suggested as a key factor causing reduction of symbiont virulence and evolution of mutualism. On the other hand, there are several mutualistic associations without vertical transmission, such as those between plants and mycorrhizal

Motomi Genkai-Kato; Norio Yamamura

1999-01-01

142

A Vertically Resolved Planetary Boundary Layer  

NASA Technical Reports Server (NTRS)

Increase of the vertical resolution of the GLAS Fourth Order General Circulation Model (GCM) near the Earth's surface and installation of a new package of parameterization schemes for subgrid-scale physical processes were sought so that the GLAS Model GCM will predict the resolved vertical structure of the planetary boundary layer (PBL) for all grid points.

Helfand, H. M.

1984-01-01

143

Combined Lateral Vertical RESURF (CLAVER) LDMOS structure  

Microsoft Academic Search

In this paper, a unique Combined Lateral Vertical RESURF (CLAVER) LDMOS structure is proposed for breakthrough performance. The structure uses a secondary RESURF design to terminate in the vertical direction to yield a much improved performance trade-off. The proposed device uses standard process steps available in integrated technology platforms to give a breakdown as high as 150 V with ground-breaking

T. Khan; V. Khemka; Ronghua Zhu; Weixiao Huang; Xu Cheng; P. Hui; Muh-ling Ger; B. Grote; P. Rodriquez

2009-01-01

144

Vertical instability and inclination excitation during planetary migration  

NASA Astrophysics Data System (ADS)

We consider a two-planet system migrating under the influence of dissipative forces that mimic the effects of gas-driven (Type II) migration. It has been shown that, in the planar case, migration leads to resonant capture after an evolution that forces the system to follow families of periodic orbits. Starting with planets that differ slightly from a coplanar configuration, capture can, also, occur and, additionally, excitation of planetary inclinations has been observed in some cases. We show that excitation of inclinations occurs, when the planar families of periodic orbits, which are followed during the initial stages of planetary migration, become vertically unstable. At these points, vertical critical orbits may give rise to generating stable families of periodic orbits, which drive the evolution of the migrating planets to non-coplanar motion. We have computed and present here the vertical critical orbits of the and resonances, for various values of the planetary mass ratio. Moreover, we determine the limiting values of eccentricity for which the "inclination resonance" occurs.

Voyatzis, G.; Antoniadou, K. I.; Tsiganis, K.

2014-08-01

145

Vertical instability and inclination excitation during planetary migration  

E-print Network

We consider a two-planet system, which migrates under the influence of dissipative forces that mimic the effects of gas-driven (Type II) migration. It has been shown that, in the planar case, migration leads to resonant capture after an evolution that forces the system to follow families of periodic orbits. Starting with planets that differ slightly from a coplanar configuration, capture can, also, occur and, additionally, excitation of planetary inclinations has been observed in some cases. We show that excitation of inclinations occurs, when the planar families of periodic orbits, which are followed during the initial stages of planetary migration, become vertically unstable. At these points, {\\em vertical critical orbits} may give rise to generating stable families of $3D$ periodic orbits, which drive the evolution of the migrating planets to non-coplanar motion. We have computed and present here the vertical critical orbits of the $2/1$ and $3/1$ resonances, for various values of the planetary mass ratio....

Voyatzis, G; Tsiganis, K

2014-01-01

146

Fluid and highly curved model membranes on vertical nanowire arrays.  

PubMed

Sensing and manipulating living cells using vertical nanowire devices requires a complete understanding of cell behavior on these substrates. Changes in cell function and phenotype are often triggered by events taking place at the plasma membrane, the properties of which are influenced by local curvature. The nanowire topography can therefore be expected to greatly affect the cell membrane, emphasizing the importance of studying membranes on vertical nanowire arrays. Here, we used supported phospholipid bilayers as a model for biomembranes. We demonstrate the formation of fluid supported bilayers on vertical nanowire forests using self-assembly from vesicles in solution. The bilayers were found to follow the contours of the nanowires to form continuous and locally highly curved model membranes. Distinct from standard flat supported lipid bilayers, the high aspect ratio of the nanowires results in a large bilayer surface available for the immobilization and study of biomolecules. We used these bilayers to bind a membrane-anchored protein as well as tethered vesicles on the nanowire substrate. The nanowire-bilayer platform shown here can be expanded from fundamental studies of lipid membranes on controlled curvature substrates to the development of innovative membrane-based nanosensors. PMID:24971634

Dabkowska, Aleksandra P; Niman, Cassandra S; Piret, Gaëlle; Persson, Henrik; Wacklin, Hanna P; Linke, Heiner; Prinz, Christelle N; Nylander, Tommy

2014-08-13

147

Origami Multistabilty: From Single Vertices to Metasheets  

E-print Network

We explore the surprisingly rich energy landscape of origami-like folding planar structures. We show that the configuration space of rigid-paneled degree-4 vertices, the simplest building blocks of such systems, consists of at least two distinct branches meeting at the flat state. This suggests that generic vertices are at least bistable, but we find that the nonlinear nature of these branches allows for vertices with as many as five distinct stable states. In vertices with collinear folds and/or symmetry, more branches emerge leading to up to six stable states. Finally, we introduce a procedure to tile arbitrary 4-vertices while preserving their stable states, thus allowing the design and creation of multistable origami metasheets.

Scott Waitukaitis; Rémi Menaut; Bryan Gin-ge Chen; Martin van Hecke

2014-08-07

148

Aerosol Vertical Distributions from GOCART Model and Comparisons with CALIPSO and In-situ Airborne Lidar Data  

NASA Technical Reports Server (NTRS)

We will show the GOCART model simulated vertical profiles of aerosol extinction, composition, and the extinction-to-backscatter ratios (lidar ratio) at different geographical regions during 2006. These results will be compared with the air-borne HSRL lidar and CALIPSO data.

Chin, Mian; Yu, Hongbin; Diehl, Thomas

2008-01-01

149

Daylight illuminance on horizontal and vertical surfaces for clear skies. Case study of shaded surfaces  

SciTech Connect

This paper presents the results of a study on daylight illuminance levels measured on horizontal and vertical surfaces. Firstly, an attempt to know the behavior of the daylight illumination in a specific area, as the 'Castilla-Leon' region, Spain, is made in order to determine the representative values of this parameter in this geographical area. With this aim, a series of measurements of global illuminance on a horizontal surface and on vertical surfaces oriented to the four cardinal points (N, S, E and W) have been collected and analyzed. In the paper, the daily evolution of this parameter is reported considering different times of the year so that a global annual behavior can be established. The study is focused on clear days. The collected data correspond to 10 min measurements carried out during the year 2007 in a rural area close to the city of Valladolid, Spain, in the mentioned region. In addition to that, the data have been treated in order to analyze the relationship between the global vertical illuminance and the corresponding horizontal illuminance. In case that no direct sunlight is reaching a vertical surface, that is, for a shaded surface, a simple parametric equation is proposed in order to predict the vertical illumination. The expression obtained shows a high correlation coefficient. It relates the ratio between vertical and horizontal illuminances versus the solar altitude; so, it permits to calculate vertical illuminance if horizontal illuminance is known. (author)

Perez-Burgos, Ana; Miguel, Argimiro de; Bilbao, Julia [Department of Applied Physics, University of Valladolid, 47005 Valladolid (Spain)

2010-01-15

150

Inclusion of Vertical Dynamics in Vertically-integrated Models for CO2 Storage  

NASA Astrophysics Data System (ADS)

Mathematical models of different complexity are needed to answer a range of questions for geological sequestration of carbon dioxide (CO2). One category of simplified models is based on vertical integration, which reduces the three-dimensional problem to two dimensions. Usually, these models assume that brine and CO2 are in vertical equilibrium. This type of model is useful and accurate for simulation times that are large relative to the time for buoyant segregation. But, vertical-equilibrium models are inappropriate in some situations, for instance, in the early stage of injection, when brine and CO2 have not fully segregated. Therefore, for these situations, the vertical equilibrium assumption needs to be relaxed and vertical dynamics needs to be included in the governing equations. To avoid significant increases of computational effort due to the inclusion of vertical dynamics, a multi-scale algorithm can be constructed where the vertically integrated equations are still used to model the (dominant) horizontal flow processes with the vertical reconstruction included as a dynamic problem. Such an approach allows each vertical column of grid cells to be solved independently, as a one-dimensional problem, during the dynamic reconstruction step. Because the top and bottom boundaries usually correspond to impermeable caprock, the total flow for these one-dimensional problems is zero and counter-current flow driven only by buoyancy and capillarity is involved. Solutions for this kind of problem are relatively simple and require little computational effort. With careful coupling between the vertical calculations and the horizontally integrated equations, an efficient algorithm can be developed to simulate a fairly wide range of problems including those with significant vertical dynamics. When vertical dynamics become insignificant, then usual vertical equilibrium reconstruction is used in the vertically integrated models. This new algorithm provides an intermediate choice in model complexity between full three-dimensional models and vertical-equilibrium two-dimensional models.

Guo, B.; Bandilla, K.; Celia, M. A.

2012-12-01

151

Prediction of Vertical Jump Height from Anthropometric Factors in Male and Female Martial Arts Athletes  

PubMed Central

Background: Vertical jump is an index representing leg/kick power. The explosive movement of the kick is the key to scoring in martial arts competitions. It is important to determine factors that influence the vertical jump to help athletes improve their leg power. The objective of the present study is to identify anthropometric factors that influence vertical jump height for male and female martial arts athletes. Methods: Twenty-nine male and 25 female athletes participated in this study. Participants were Malaysian undergraduate students whose ages ranged from 18 to 24 years old. Their heights were measured using a stadiometer. The subjects were weighted using digital scale. Body mass index was calculated by kg/m2. Waist–hip ratio was measured from the ratio of waist to hip circumferences. Body fat % was obtained from the sum of four skinfold thickness using Harpenden callipers. The highest vertical jump from a stationary standing position was recorded. The maximum grip was recorded using a dynamometer. For standing back strength, the maximum pull upwards using a handle bar was recorded. Multiple linear regression was used to obtain the relationship between vertical jump height and explanatory variables with gender effect. Results: Body fat % has a significant negative relationship with vertical jump height (P < 0.001). The effect of gender is significant (P < 0.001): on average, males jumped 26% higher than females did. Conclusion: Vertical jump height of martial arts athletes can be predicted by body fat %. The vertical jump for male is higher than for their female counterparts. Reducing body fat by proper dietary planning will help to improve leg power. PMID:23785254

Abidin, Nahdiya Zainal; Adam, Mohd Bakri

2013-01-01

152

Contribution A.55 -Monday, June 19 Growth mechanism of vertically aligned  

E-print Network

@photon.t.u-tokyo.ac.jp Following the first realization of VA-SWNTs [1] by alcohol catalytic CVD (ACCVD) method, various techniques are reported for the vertical aligned grow- th such as control of water, point-arc microwave plasma CVD, molecular-beam CVD, hot-filament control of atomic hydrogen, hydrogen/oxygen ratio control by oxygen

Maruyama, Shigeo

153

A vertically integrated model with vertical dynamics for CO2 storage  

NASA Astrophysics Data System (ADS)

vertically integrated models for CO2 storage usually adopt a vertical equilibrium (VE) assumption, which states that due to strong buoyancy, CO2 and brine segregate quickly, so that the fluids can be assumed to have essentially hydrostatic pressure distributions in the vertical direction. However, the VE assumption is inappropriate when the time scale of fluid segregation is not small relative to the simulation time. By casting the vertically integrated equations into a multiscale framework, a new vertically integrated model can be developed that relaxes the VE assumption, thereby allowing vertical dynamics to be modeled explicitly. The model maintains much of the computational efficiency of vertical integration while allowing a much wider range of problems to be modeled. Numerical tests of the new model, using injection scenarios with typical parameter sets, show excellent behavior of the new approach for homogeneous geologic formations.

Guo, Bo; Bandilla, Karl W.; Doster, Florian; Keilegavlen, Eirik; Celia, Michael A.

2014-08-01

154

Methods of testing parameterizations: Vertical ocean mixing  

NASA Technical Reports Server (NTRS)

The ocean's velocity field is characterized by an exceptional variety of scales. While the small-scale oceanic turbulence responsible for the vertical mixing in the ocean is of scales a few centimeters and smaller, the oceanic general circulation is characterized by horizontal scales of thousands of kilometers. In oceanic general circulation models that are typically run today, the vertical structure of the ocean is represented by a few tens of discrete grid points. Such models cannot explicitly model the small-scale mixing processes, and must, therefore, find ways to parameterize them in terms of the larger-scale fields. Finding a parameterization that is both reliable and plausible to use in ocean models is not a simple task. Vertical mixing in the ocean is the combined result of many complex processes, and, in fact, mixing is one of the less known and less understood aspects of the oceanic circulation. In present models of the oceanic circulation, the many complex processes responsible for vertical mixing are often parameterized in an oversimplified manner. Yet, finding an adequate parameterization of vertical ocean mixing is crucial to the successful application of ocean models to climate studies. The results of general circulation models for quantities that are of particular interest to climate studies, such as the meridional heat flux carried by the ocean, are quite sensitive to the strength of the vertical mixing. We try to examine the difficulties in choosing an appropriate vertical mixing parameterization, and the methods that are available for validating different parameterizations by comparing model results to oceanographic data. First, some of the physical processes responsible for vertically mixing the ocean are briefly mentioned, and some possible approaches to the parameterization of these processes in oceanographic general circulation models are described in the following section. We then discuss the role of the vertical mixing in the physics of the large-scale ocean circulation, and examine methods of validating mixing parameterizations using large-scale ocean models.

Tziperman, Eli

1992-01-01

155

Vertical Vegetation Structure Below Ground: Scaling from Root to Globe  

E-print Network

exhibit a vertical structure that responds to resources that have a strong vertical dimension, light aboveVertical Vegetation Structure Below Ground: Scaling from Root to Globe H. Jochen Schenk So sind,there ought to be predictable relation- ships between vertical vegetation structure and the vertical

Schenk, H. Jochen

156

CRISTA-NF measurements with unprecedented vertical resolution made during the RECONCILE aircraft campaign  

NASA Astrophysics Data System (ADS)

The Cryogenic Infrared Spectrometers and Telescope for the Atmosphere - New Frontiers (CRISTA-NF), an airborne infrared limb-sounder, was operated aboard the high-flying Russian research aircraft M55-Geophysica during the Arctic RECONCILE campaign from January to March 2011. This poster describes the calibration process of the instrument and the employed retrieval algorithm and then proceeds to present retrieved trace gas mixing ratio cross-sections for one specific flight of this campaign. We are able to resolve the uppermost troposphere / lower stratosphere for several trace gas species for several kilometres below the flight altitude (16 to 19km) with an unprecedented vertical resolution of 400 to 500m for the limb-sounding technique. The observations are also characterised by a rather high horizontal sampling along the flight track that provides a full vertical profile every ?15km. Assembling the vertical trace gas profiles derived from CRISTA-NF measurements to cross-sections depicts filaments of vortex and extra-vortex air masses in the vicinity of the polar vortex. By using horizontal regularisation, the vertical resolution of the retrieved volume mixing ratios could be improved even further, especially for trace gases with a low signal-to-noise ratio. During this campaign, the M55-Geophysica carried further instruments, which allows for a validation of trace gas mixing ratios derived from CRISTA-NF against measurements by the in situ instruments HAGAR and FOZAN and observations by MIPAS-STR. This validation sug- gests that the retrieved trace gas mixing ratios are both qualitatively and quantitatively reliable. The derived dataset allows the observation of several filaments of air with a very small vertical extent in the order of 500m to 1km in the lower stratosphere. These filaments stem from different sources and can be exploited to examine mixing processes in the lower stratosphere.

Ungermann, J.; Guggenmoser, T.; Kalicinsky, C.; Riese, M.

2012-04-01

157

Vertical wind estimation from horizontal wind measurements  

NASA Technical Reports Server (NTRS)

The objective of this study was to assess the ability of simple vertical wind models to improve the hazard prediction capability of an airborne Doppler sensor in a realistic microburst environment. The results indicate that in the altitude region of interest (at or below 300 meters), both the linear and empirical vertical wind models improved the hazard estimate. The radar simulation study showed that the magnitude of the performance improvement was altitude dependent. The altitude of maximum performance improvement occurred at about 300 meters. At the lower altitudes the percent improvement was minimized by the diminished contribution of the vertical wind. The vertical hazard estimate errors from flight tests were less than those of the radar simulation study.

Vicroy, Dan D.

1994-01-01

158

Continuous Growth of Vertically Aligned Carbon Nanotubes  

E-print Network

Vertically aligned carbon nanotubes (VACNTs), sometimes called forests or carpets, are a promising material due to their unique physical and scale-dependent physical properties [1-3]. Continuous production of VACNTs is ...

Guzman de Villoria, R.

159

High ratio recirculating gas compressor  

DOEpatents

A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor.

Weinbrecht, John F. (601 Oakwood Pl., NE., Albuquerque, NM 87123)

1989-01-01

160

High ratio recirculating gas compressor  

DOEpatents

A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

Weinbrecht, J.F.

1989-08-22

161

On the vertical excitation energy of cyclopentadiene  

NASA Astrophysics Data System (ADS)

The vertical excitation energy for the lowest valence ???* transition of cyclopentadiene is investigated. Using a combination of high-level theoretical methods and spectroscopic simulations, the vertical separation at the ground state geometry is estimated to be 5.43±0.05 eV. This value is intermediate between those calculated with coupled-cluster and multireference perturbation theory methods and is about 0.13 eV higher than the observed maximum in the absorption profile.

Bomble, Yannick J.; Sattelmeyer, Kurt W.; Stanton, John F.; Gauss, Jürgen

2004-09-01

162

Effects of volume averaging on the line spectra of vertical velocity from multiple-Doppler radar observations  

NASA Technical Reports Server (NTRS)

Calculations of the ratio of the true one-dimensional spectrum of vertical velocity and that measured with multiple-Doppler radar beams are presented. It was assumed that the effects of pulse volume averaging and objective analysis routines is replacement of a point measurement with a volume integral. A u and v estimate was assumed to be feasible when orthogonal radars are not available. Also, the target fluid was configured as having an infinite vertical dimension, zero vertical velocity at the top and bottom, and having homogeneous and isotropic turbulence with a Kolmogorov energy spectrum. The ratio obtained indicated that equal resolutions among radars yields a monotonically decreasing, wavenumber-dependent response function. A gain of 0.95 was demonstrated in an experimental situation with 40 levels. Possible errors introduced when using unequal resolution radars were discussed. Finally, it was found that, for some flows, the extent of attenuation depends on the number of vertical levels resolvable by the radars.

Gal-Chen, T.; Wyngaard, J. C.

1982-01-01

163

[Is the sense of verticality vestibular?].  

PubMed

The vestibular system constitutes an inertial sensor, which detects linear (otoliths) and angular (semicircular canals) accelerations of the head in the three dimensions. The otoliths are specialized in the detection of linear accelerations and can be used by the brain as a "plumb line" coding earth gravity acceleration (direction). This property of otolithic system suggested that the sense of verticality is supported by the vestibular system. The preeminence of vestibular involvement in the sense of verticality stated in the 1900s was progressively supplanted by the notion of internal models of verticality. The internal models of verticality involve rules and properties of integration of vestibular graviception, somaesthesic graviception, and vision. The construction of a mental representation of verticality was mainly modeled as a bottom-up organization integrating visual, somatosensory and vestibular information without any cognitive modulations. Recent studies reported that the construction of internal models of verticality is not an automatic multi-sensory integration process but corresponds to more complex mechanisms including top-down influences such as awareness of body orientation or spatial representations. PMID:23856176

Barra, J; Pérennou, D

2013-06-01

164

47 CFR 73.160 - Vertical plane radiation characteristics, f(?).  

Code of Federal Regulations, 2012 CFR

...to the horizontal plane. The vertical angle, represented as ?...the horizontal plane. The vertical plane radiation characteristic...computing radiation in the vertical plane, unless the applicant...formula for a particular type of antenna. If a special formula...

2012-10-01

165

47 CFR 73.160 - Vertical plane radiation characteristics, f(?).  

Code of Federal Regulations, 2010 CFR

...to the horizontal plane. The vertical angle, represented as ?...the horizontal plane. The vertical plane radiation characteristic...computing radiation in the vertical plane, unless the applicant...formula for a particular type of antenna. If a special formula...

2010-10-01

166

47 CFR 73.160 - Vertical plane radiation characteristics, f(?).  

Code of Federal Regulations, 2011 CFR

...to the horizontal plane. The vertical angle, represented as ?...the horizontal plane. The vertical plane radiation characteristic...computing radiation in the vertical plane, unless the applicant...formula for a particular type of antenna. If a special formula...

2011-10-01

167

47 CFR 73.160 - Vertical plane radiation characteristics, f(?).  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Vertical plane radiation characteristics, f(θ). 73.160...Stations § 73.160 Vertical plane radiation characteristics, f(?). (a) The vertical plane radiation characteristics show the...

2013-10-01

168

Observed changes in the vertical profile of stratopheric nitrous oxide at Thule, Greenland, February - March 1992  

NASA Technical Reports Server (NTRS)

Using a ground-based mm-wave spectrometer, we have observed stratospheric N2O over Thule, Greenland (76.3 N, 68.4 W) during late February and March, 1992. Vertical profiles of mixing ratio ranging from 16 to 50 km were recovered from molecular emission spectra. The profiles of early March show an abrupt increase in the lower-stratosphere N2O mixing ratio similar to the spring-to-summer change associated with the break up of the Antarctic polar vortex. This increase is correlated with changes in potential vorticity, air temperature, and ozone mixing ratio.

Emmons, Louisa K.; Reeves, John M.; Shindell, Drew T.; Dezafra, Robert L.

1994-01-01

169

Comparison of Aerosol Classification From Airborne High Spectral Resolution Lidar and the CALIPSO Vertical Feature Mask  

NASA Technical Reports Server (NTRS)

Knowledge of aerosol composition and vertical distribution is crucial for assessing the impact of aerosols on climate. In addition, aerosol classification is a key input to CALIOP aerosol retrievals, since CALIOP requires an inference of the lidar ratio in order to estimate the effects of aerosol extinction and backscattering. In contrast, the NASA airborne HSRL-1 directly measures both aerosol extinction and backscatter, and therefore the lidar ratio (extinction-to-backscatter ratio). Four aerosol intensive properties from HSRL-1 are combined to infer aerosol type. Aerosol classification results from HSRL-1 are used here to validate the CALIOP aerosol type inferences.

Burton, Sharon P.; Ferrare, Rich A.; Omar, Ali H.; Vaughan, Mark A.; Rogers, Raymond R.; Hostetler, Chris a.; Hair, Johnathan W.; Obland, Michael D.; Butler, Carolyn F.; Cook, Anthony L.; Harper, David B.

2012-01-01

170

Unsteady mixed convective flow and heat transfer in a vertical corrugated channel with composite porous media  

NASA Astrophysics Data System (ADS)

An unsteady mixed convective flow and heat transfer in a vertical corrugated channel containing porous and fluid layers are considered. The equations of momentum and energy are solved under appropriate boundary and interface conditions with the assumption that the solution consists of a mean part and a perturbed one. The exact solutions are obtained in the long-wave approximation. Separate solutions are matched at the interface with the use of suitable matching conditions. The effects of pertinent parameters, such as the Grashof number, viscosity ratio, width ratio, conductivity ratio, frequency, and the wave parameter on the flow field and heat transfer characteristics are studied.

Umavathi, J. C.; Shekar, M.

2013-07-01

171

Should sex-ratio distorting parasites abandon horizontal transmission?  

PubMed Central

Background Sex-ratio distorting parasites are of interest due to their effects upon host population dynamics and their potential to influence the evolution of host sex determination systems. In theory, the ability to distort host sex-ratios allows a parasite with efficient vertical (hereditary) transmission to dispense completely with horizontal (infectious) transmission. However, recent empirical studies indicate that some sex-ratio distorting parasites have retained the capability for horizontal transmission. Results Numerical simulations using biologically realistic parameters suggest that a feminising parasite is only likely to lose the capability for horizontal transmission if its host occurs at low density and/or has a male-biased primary sex ratio. It is also demonstrated that even a small amount of horizontal transmission can allow multiple feminising parasites to coexist within a single host population. Finally it is shown that, by boosting its host's rate of population growth, a feminising parasite can increase its own horizontal transmission and allow the invasion of other, more virulent parasites. Conclusions The prediction that sex-ratio distorting parasites are likely to retain a degree of horizontal transmission has important implications for the epidemiology and host-parasite interactions of these organisms. It may also explain the frequent co-occurrence of several sex-ratio distorting parasite species in nature. PMID:22188680

2011-01-01

172

Pressure Ratio to Thermal Environments  

NASA Technical Reports Server (NTRS)

A pressure ratio to thermal environments (PRatTlE.pl) program is a Perl language code that estimates heating at requested body point locations by scaling the heating at a reference location times a pressure ratio factor. The pressure ratio factor is the ratio of the local pressure at the reference point and the requested point from CFD (computational fluid dynamics) solutions. This innovation provides pressure ratio-based thermal environments in an automated and traceable method. Previously, the pressure ratio methodology was implemented via a Microsoft Excel spreadsheet and macro scripts. PRatTlE is able to calculate heating environments for 150 body points in less than two minutes. PRatTlE is coded in Perl programming language, is command-line-driven, and has been successfully executed on both the HP and Linux platforms. It supports multiple concurrent runs. PRatTlE contains error trapping and input file format verification, which allows clear visibility into the input data structure and intermediate calculations.

Lopez, Pedro; Wang, Winston

2012-01-01

173

Arcjet Nozzle Area Ratio Effects  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

1990-01-01

174

Arcjet nozzle area ratio effects  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

1990-01-01

175

Relation of vertical flux of particles smaller than 10 ?m to total aeolian horizontal mass flux at Owens Lake  

Microsoft Academic Search

The vertical flux of particles smaller than 10\\/xm for a saline playa surface, the particle size composition of which was classified as loam-textured, was estimated for a highly wind-erodible site on the playa of Owens (dry) Lake in California. The ratio of this vertical flux to the horizontal flux of total airborne material through a surface perpendicular to the soil

Dale A. Gillette; D. W. Fryrear; Thomas E. Gill; Trevor Ley; Thomas A. Cahill; Elizabeth A. Gearhart

1997-01-01

176

Measurement of the $B^{+}$ and $B^{0}$ lifetimes and search for CP(T) violation using reconstructed secondary vertices  

Microsoft Academic Search

The lifetimes of the B+ and B0 mesons, and their ratio, have been measured in the OPAL experiment using 2.4 million hadronic Z0 decays recorded at LEP. Z0 -> b bbar decays were tagged using displaced secondary vertices and high momentum electrons and muons. The lifetimes were then measured using well-reconstructed charged and neutral secondary vertices selected in this tagged

G Abbiendi; K Ackerstaff; Gideon Alexander; J Allison; N Altekamp; K J Anderson; S Anderson; S Arcelli; S Asai; S F Ashby; D A Axen; Georges Azuelos; A H Ball; E Barberio; R J Barlow; R Bartoldus; J Richard Batley; S Baumann; J Bechtluft; T Behnke; K W Bell; G Bella; A Bellerive; Stanislaus Cornelius Maria Bentvelsen; Siegfried Bethke; S Betts; O Biebel; A Biguzzi; S D Bird; Volker Blobel; Ian J Bloodworth; P Bock; J Böhme; D Bonacorsi; M Boutemeur; S Braibant; P G Bright-Thomas; L Brigliadori; R M Brown; Helfried J Burckhart; P Capiluppi; R K Carnegie; A A Carter; J R Carter; C Y Chang; D G Charlton; D Chrisman; C Ciocca; P E L Clarke; E Clay; I Cohen; J E Conboy; O C Cooke; C Couyoumtzelis; R L Coxe; M Cuffiani; S Dado; G M Dallavalle; R Davis; S De Jong; A de Roeck; P J Dervan; Klaus Desch; B Dienes; M S Dixit; J Dubbert; E Duchovni; G Duckeck; I P Duerdoth; D Eatough; P G Estabrooks; E Etzion; Franco Luigi Fabbri; M Fanti; A A Faust; F Fiedler; M Fierro; I Fleck; R Folman; A Fürtjes; D I Futyan; P Gagnon; J W Gary; J Gascon; S M Gascon-Shotkin; G Gaycken; C Geich-Gimbel; G Giacomelli; P Giacomelli; V Gibson; W R Gibson; D M Gingrich; D A Glenzinski; J Goldberg; W Gorn; C Grandi; K Graham; E Gross; Jacob Grunhaus; M Gruwé; G G Hanson; M Hansroul; M Hapke; K Harder; A Harel; C K Hargrove; C Hartmann; M Hauschild; C M Hawkes; R Hawkings; Richard J Hemingway; M Herndon; G Herten; R D Heuer; M D Hildreth; J C Hill; P R Hobson; M Hoch; Andreas Höcker; K Hoffman; R James Homer; A K Honma; D Horváth; K R Hossain; R Howard; P Hüntemeyer; P Igo-Kemenes; D C Imrie; K Ishii; F R Jacob; A Jawahery; H Jeremie; Martin Paul Jimack; C R Jones; P Jovanovic; T R Junk; D A Karlen; V G Kartvelishvili; K Kawagoe; T Kawamoto; P I Kayal; Richard K Keeler; R G Kellogg; B W Kennedy; D H Kim; A Klier; S Kluth; T Kobayashi; M Kobel; D S Koetke; T P Kokott; M Kolrep; S Komamiya; R V Kowalewski; T Kress; P Krieger; J Von Krogh; T Kühl; P Kyberd; G D Lafferty; Hagar Yaël Landsman; D Lanske; J Lauber; S R Lautenschlager; I Lawson; J G Layter; D Lazic; A M Lee; Daniel Lellouch; J Letts; L Levinson; R Liebisch; B List; C Littlewood; A W Lloyd; S L Lloyd; F K Loebinger; G D Long; Michael J Losty; J Ludwig; D Liu; A Macchiolo; A L MacPherson; W F Mader; M Mannelli; S Marcellini; C Markopoulos; A J Martin; J P Martin; G Martínez; T Mashimo; P Mättig; W J McDonald; J A McKenna; E A McKigney; T J McMahon; R A McPherson; F Meijers; S Menke; F S Merritt; H Mes; J Meyer; Aldo Michelini; S Mihara; G Mikenberg; D J Miller; R Mir; W Mohr; A Montanari; T Mori; K Nagai; I Nakamura; H A Neal; B Nellen; R Nisius; S W O'Neale; F G Oakham; F Odorici; H O Ögren; M J Oreglia; S Orito; J Pálinkás; G Pásztor; J R Pater; G N Patrick; J Patt; R Pérez-Ochoa; S Petzold; P Pfeifenschneider; J E Pilcher; James L Pinfold; D E Plane; P R Poffenberger; J Polok; M B Przybycien; C Rembser; Hartmut Rick; S Robertson; S A Robins; N L Rodning; J M Roney; K Roscoe; A M Rossi; Y Rozen; K Runge; O Runólfsson; D R Rust; K Sachs; T Saeki; O Sahr; W M Sang; E Sarkisyan-Grinbaum; C Sbarra; A D Schaile; O Schaile; F Scharf; P Scharff-Hansen; J Schieck; B Schmitt; S Schmitt; A Schöning; M Schröder; M Schumacher; C Schwick; W G Scott; R Seuster; T G Shears; B C Shen; C H Shepherd-Themistocleous; P Sherwood; G P Siroli; A Sittler; A Skuja; A M Smith; G A Snow; Randall J Sobie; S Söldner-Rembold; S Spagnolo; M Sproston; A Stahl; K Stephens; J Steuerer; K Stoll; D Strom; R Ströhmer; B Surrow; S D Talbot; S Tanaka; P Taras; S Tarem; R Teuscher; M Thiergen; J Thomas; M A Thomson; E Von Törne; E Torrence; S Towers; I Trigger; Z L Trócsányi; E Tsur; A S Turcot; M F Turner-Watson; I Ueda; R Van Kooten; P Vannerem; M Verzocchi; H Voss; F Wäckerle; A Wagner; C P Ward; D R Ward; P M Watkins; A T Watson; N K Watson; P S Wells; N Wermes; J S White; G W Wilson; J A Wilson; T R Wyatt; S Yamashita; G Yekutieli; V Zacek; D Zer-Zion

1998-01-01

177

WHICH HYDRAULIC MODEL TO USE IN VERTICAL FLOW CONSTRUCTED WETLANDS?  

E-print Network

WHICH HYDRAULIC MODEL TO USE IN VERTICAL FLOW CONSTRUCTED WETLANDS? Ania Morvannoua , Nicolas-equilibrium model, preferential flow path, vertical flow constructed wetlands INTRODUCTION Constructed wetlands (CWs

Paris-Sud XI, Université de

178

Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross ...  

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

Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross Bracing Detail, Vertical Cross Bracing-End Detail - Cumberland Covered Bridge, Spanning Mississinewa River, Matthews, Grant County, IN

179

Method and apparatus for determining vertical heat flux of geothermal field  

DOEpatents

A method and apparatus for determining vertical heat flux of a geothermal field, and mapping the entire field, is based upon an elongated heat-flux transducer (10) comprised of a length of tubing (12) of relatively low thermal conductivity with a thermopile (20) inside for measuring the thermal gradient between the ends of the transducer after it has been positioned in a borehole for a period sufficient for the tube to reach thermal equilibrium. The transducer is thermally coupled to the surrounding earth by a fluid annulus, preferably water or mud. A second transducer comprised of a length of tubing of relatively high thermal conductivity is used for a second thermal gradient measurement. The ratio of the first measurement to the second is then used to determine the earth's thermal conductivity, k.sub..infin., from a precalculated graph, and using the value of thermal conductivity thus determined, then determining the vertical earth temperature gradient, b, from predetermined steady state heat balance equations which relate the undisturbed vertical earth temperature distributions at some distance from the borehole and earth thermal conductivity to the temperature gradients in the transducers and their thermal conductivity. The product of the earth's thermal conductivity, k.sub..infin., and the earth's undisturbed vertical temperature gradient, b, then determines the earth's vertical heat flux. The process can be repeated many times for boreholes of a geothermal field to map vertical heat flux.

Poppendiek, Heinz F. (LaJolla, CA)

1982-01-01

180

LETTER TO THE EDITOR: Ultrahigh-density silicon nanobridges formed between two vertical silicon surfaces  

NASA Astrophysics Data System (ADS)

We report simultaneous lateral growth of a high density of highly oriented, metal-catalyzed silicon nanowires on a patterned silicon substrate and bridging of nanowires between two vertical silicon sidewalls, which can be developed into electrodes of an electronic device. After angled deposition of catalytic metal nanoparticles on one of two opposing vertical silicon surfaces, we used a metal-catalyzed chemical vapour deposition process to grow nanowires and eventually form mechanically robust 'nanobridges'. The growth and bridging of these nanowire arrays can be integrated with existing silicon processes. This method of connecting multiple nanowires between two electrodes offers the high surface-to-volume ratio needed for nanosensor applications.

Saif Islam, M.; Sharma, S.; Kamins, T. I.; Williams, R. Stanley

2004-05-01

181

Measurements of the vertical profile of water vapor abundance in the Martian atmosphere from Mars Observer  

NASA Technical Reports Server (NTRS)

An analysis is presented of the Pressure Modulator Infrared Radiometer (PMIRR) capabilities along with how the vertical profiles of water vapor will be obtained. The PMIRR will employ filter and pressure modulation radiometry using nine spectral channels, in both limb scanning and nadir sounding modes, to obtain daily, global maps of temperature, dust extinction, condensate extinction, and water vapor mixing ratio profiles as a function of pressure to half scale height or 5 km vertical resolution. Surface thermal properties will also be mapped, and the polar radiactive balance will be monitored.

Schofield, J. T.; Mccleese, Daniel J.

1988-01-01

182

Point Estimation: Odds Ratios, Hazard Ratios, Risk Differences, Precision  

NSDL National Science Digital Library

This site provides a PowerPoint presentation, created by Dr. Elizabeth Garrett-Mayer of Johns Hopkins University, of a lesson and examples of point estimation, odds ratios, hazard ratios, risk differences and precision. The presentations is quite thorough. The author attempts to define, provide examples of, and then show the application of almost every concept. The presentation follows a easily followed and logical order. Mathematical formulas are intertwined within the slides. If further research is necessary, the author has provided a list of references and cites them during the presentation.

Garrett-Mayer, Elizabeth

2009-02-11

183

Comparison of Vertical and Inverted-T Mammaplasties Using Photographic Measurements  

PubMed Central

Background: Surgeons have long debated the relative merits of vertical and inverted-T mammaplasties. These debates have centered on surgeons’ opinions. Without measurements, this controversy is unlikely to be resolved. This study compares these common techniques using a recently published measurement system. Such a study using measurements on photographs matched for size and orientation has not been previously published. Methods: A prospective group of women undergoing primary vertical mastopexies, augmentation/mastopexies, and reductions (n = 78) was compared with a retrospective group of women treated with inverted-T mastopexies, augmentation/mastopexies, and reductions (n = 35). Consecutive patients with photographs at least 3 months after surgery and no subsequent procedures were evaluated. Results: All patient groups demonstrated a significant elevation (P < 0.001) of the breast mound. Vertical mastopexy, but not inverted-T mastopexy, increased breast projection and upper pole projection (P < 0.008). Neither vertical nor inverted-T breast reduction significantly increased breast projection. Vertical breast reduction better preserved breast projection (P < 0.017) than the inverted-T technique. Vertical reduction significantly increased upper pole projection (P < 0.008), but inverted-T reduction did not. The inverted-T breast reduction caused greater breast constriction (reduced lower pole distance) than the vertical technique. Lower pole ratios were significantly higher for inverted-T patients (P < 0.01), indicating boxier lower poles. Conclusions: Photographic measurements of relevant breast parameters favor the vertical technique over the inverted-T technique and are consistent with anatomical considerations and clinical experience.

2013-01-01

184

Wetting and surface energy of vertically aligned silicon nanowires.  

PubMed

The vertically aligned silicon nanowires (SiNWs) have been synthesized by metal assisted chemical etching process on commercially available p type silicon wafer. The aspect ratios of the SiNWs have been modified by simply varying the etching time. The microstructures of the as prepared samples have been investigated with the field emission scanning electron microscope as well as with a high resolution transmission electron microscope. The bonding information has been obtained by Fourier transformed infrared spectroscopy and X-ray photoelectron spectroscopy. The contact angles for water with the as-prepared SiNWs films were measured and found to be highly dependent upon the aspect ratio of the as synthesized wires. For obtaining a deep insight regarding the reasons behind this dependence the surface energies of the as prepared SiNWs films have been calculated by Owens method using two liquids, water and glycerol. The porosity of the films has been calculated indirectly from the equilibrium equations. It has been found that the etching time has a profound effect on the aspect ratio and thus on the surface energy of SiNWs that governs the wetting behaviour of the as prepared samples. PMID:23862437

Jana, S; Mondal, S; Bhattacharyya, S R

2013-06-01

185

Climatology of tropospheric vertical velocity spectra  

NASA Technical Reports Server (NTRS)

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.

Ecklund, W. L.; Gage, K. S.; Balsley, B. B.; Carter, D. A.

1986-01-01

186

Isotopic ratios in planetary atmospheres.  

PubMed

Recent progress on measurements of isotopic ratios in planetary or satellite atmospheres include measurements of the D/H ratio in the methane of Uranus, Neptune and Titan and in the water of Mars and Venus. Implications of these measurements on our understanding of the formation and evolution of the planets and satellite are discussed. Our current knowledge of the carbon, nitrogen and oxygen isotopic ratios in the atmospheres of these planets, as well as on Jupiter and Saturn, is also reviewed. We finally show what progress can be expected in the very near future due to some new ground-based instrumentation particularly well suited to such studies, and to forthcoming space missions. PMID:11539257

de Bergh, C

1995-03-01

187

Antistick postpassivation of high-aspect ratio silicon molds fabricated by deep-reactive ion etching  

Microsoft Academic Search

High-aspect ratio (HAR) silicon molds formed with deep-reactive ion etching (DRIE) technique are difficult to use as masters for replication, especially for replication of high-aspect ratio microstructures. Microstructures in silicon molds made by DRIE have high surface energy and wavy vertical side walls, both of which make demolding difficult. In the research reported here, microstructured silicon master molds were made

J. X. Gao; L. P. Yeo; M. B. Chan-Park; J. M. Miao; Y. H. Yan; J. B. Sun; Y. C. Lam; C. Y. Yue

2006-01-01

188

Surface to Volume Ratio Activity  

NSDL National Science Digital Library

By the National Nanotechnology Infrastructure Network, this two-part laboratory activity was designed to complement any chemistry unit on catalysts to "help students understand how nanoparticles may be more effective catalysts by investigating how the surface area-to-volume ratio of a substance is affected as its shape changes." On this site, educators can find both the teacher and student instructions for preparing and presenting the laboratory with objectives, time periods, materials, procedures, example answers, and much more. It is a ready-to-use lesson to help students understand catalysts and surface to volume ratio at molecular and atomic levels.

2009-01-14

189

Theoretical calculations of the pressure, forces, and moments at supersonic speeds due to various lateral motions acting on thin isolated vertical tails  

NASA Technical Reports Server (NTRS)

Velocity potentials, pressure, distributions, and stability derivatives are derived by use of supersonic linearized theory for families of thin isolated vertical tails performing steady rolling, steady yawing, and constant-lateral-acceleration motions. Vertical-tail families (half-delta and rectangular plan forms) are considered for a broad Mach number range. Also considered are the vertical tail with arbitrary sweepback and taper ratio at Mach numbers for which both the leading edge and trailing edge of the tail are supersonic and the triangular vertical tail with a subsonic leading edge and a supersonic trailing edge. Expressions for potentials, pressures, and stability derivatives are tabulated.

Margolis, Kenneth; Bobbitt, Percy J

1956-01-01

190

Vertical Velocity Measurements in Warm Stratiform Clouds  

NASA Astrophysics Data System (ADS)

Measurements of vertical air motion in warm boundary layer clouds are key for quantitatively describing cloud-scale turbulence and for improving our understanding of cloud and drizzle microphysical processes. Recently, a new technique that produces seamless measurements of vertical air velocity in the cloud and sub-cloud layers for both drizzling and non-drizzling stratocumulus clouds has been developed. The technique combines radar Doppler spectra-based retrievals of vertical air motion in cloud and light drizzle conditions with a novel neural network analysis during heavily drizzling periods. Observations from Doppler lidars are used to characterize sub-cloud velocities and to evaluate the performance of the technique near the cloud base. The technique is applied to several cases of stratiform clouds observed by the ARM Mobile Facility during the Two-Column Aerosol Project (TCAP) campaign in Cape Cod. The observations clearly illustrate coupling of the sub-cloud and cloud layer turbulent structures.

Luke, E. P.; Kollias, P.

2013-12-01

191

Purification process for vertically aligned carbon nanofibers  

NASA Technical Reports Server (NTRS)

Individual, free-standing, vertically aligned multiwall carbon nanotubes or nanofibers are ideal for sensor and electrode applications. Our plasma-enhanced chemical vapor deposition techniques for producing free-standing and vertically aligned carbon nanofibers use catalyst particles at the tip of the fiber. Here we present a simple purification process for the removal of iron catalyst particles at the tip of vertically aligned carbon nanofibers derived by plasma-enhanced chemical vapor deposition. The first step involves thermal oxidation in air, at temperatures of 200-400 degrees C, resulting in the physical swelling of the iron particles from the formation of iron oxide. Subsequently, the complete removal of the iron oxide particles is achieved with diluted acid (12% HCl). The purification process appears to be very efficient at removing all of the iron catalyst particles. Electron microscopy images and Raman spectroscopy data indicate that the purification process does not damage the graphitic structure of the nanotubes.

Nguyen, Cattien V.; Delziet, Lance; Matthews, Kristopher; Chen, Bin; Meyyappan, M.

2003-01-01

192

Liquid storage tanks under vertical excitation  

SciTech Connect

Until recently, the hydrodynamic effects on liquid storage tanks induced by an earthquake excitation were basically treated for the horizontal component of the earthquake. Recent studies, however, showed that the hydrodynamic effects due to the vertical component of an earthquake may be significant. In these studies the tank is assumed to be fixed at the bottom. This paper is concerned with the hydrodynamic behavior of liquid storage tanks induced by vertical earthquake input excitation. First, the fluid-tank system is treated as a fixed-base system and a simple formula is obtained for the coupled fluid-structure natural frequency. Second, additional interaction effects due to the foundation flexibility on the fluid-tank system are investigated. It is concluded that the foundation flexibility may have a significant effect on the hydrodynamic behavior of the liquid storage tanks under a vertical ground shaking.

Philippacopoulos, A.J.

1985-01-01

193

Capacity Planning for Vertical Search Engines  

E-print Network

Vertical search engines focus on specific slices of content, such as the Web of a single country or the document collection of a large corporation. Despite this, like general open web search engines, they are expensive to maintain, expensive to operate, and hard to design. Because of this, predicting the response time of a vertical search engine is usually done empirically through experimentation, requiring a costly setup. An alternative is to develop a model of the search engine for predicting performance. However, this alternative is of interest only if its predictions are accurate. In this paper we propose a methodology for analyzing the performance of vertical search engines. Applying the proposed methodology, we present a capacity planning model based on a queueing network for search engines with a scale typically suitable for the needs of large corporations. The model is simple and yet reasonably accurate and, in contrast to previous work, considers the imbalance in query service times among homogeneous...

Badue, Claudine; Almeida, Virgilio; Baeza-Yates, Ricardo; Ribeiro-Neto, Berthier; Ziviani, Artur; Ziviani, Nivio

2010-01-01

194

Damping of vertical coronal loop kink oscillations through wave tunneling  

NASA Astrophysics Data System (ADS)

The decay rate of vertical kink waves in a curved flux tube is modeled numerically. The full MHD equations are solved for a curved equilibrium flux tube in an arcade geometry and the decay of ?, the integral over the flux tube of the modulus of the velocity perpendicular to the local magnetic field, is measured. These simulations are 2D and are thus restricted to kink oscillations in the loop plane. The decay rate is found to increase with increasing wavelength, increasing ? and decreasing density contrast ratio. The wave tunneling effect is shown to be a possible mechanism for the high decay rate of the recent observed kink oscillation reported by Wang & Solanki (2004).

Brady, C. S.; Arber, T. D.

2005-08-01

195

Optimal maneuvers at supersonic speeds in a vertical plane  

NASA Technical Reports Server (NTRS)

This paper presents several optimal maneuvers of supersonic aircraft in a vertical plane. The general dimensionless equations of motion are derived and the computation of the optimal trajectories are carried out using the aerodynamics and engine characteristics of a light-weight fighter called the supercruiser. Because of the normalizing of the control variables, namely, the load factor and the thrust-to-weight ratio, the results applied to any supersonic aircraft. The optimality of the singular thrust control and the optimal junction of different subarcs are discussed. The proposed method of computing the optimal trajectory is very efficient and makes explicit the selection of the optimal control. The technique should be useful for performance assessment of supersonic aircraft with potential for implementation of onboard flight control system.

Vinh, N. X.; Lin, C. F.

1981-01-01

196

Single transverse mode selectively oxidized vertical cavity lasers  

SciTech Connect

Vertical cavity surface emitting lasers (VCSELs) which operate in multiple transverse optical modes have been rapidly adopted into present data communication applications which rely on multi-mode optical fiber. However, operation only in the fundamental mode is required for free space interconnects and numerous other emerging VCSEL applications. Two device design strategies for obtaining single mode lasing in VCSELs based on mode selective loss or mode selective gain are reviewed and compared. Mode discrimination is attained with the use of a thick tapered oxide aperture positioned at a longitudinal field null. Mode selective gain is achieved by defining a gain aperture within the VCSEL active region to preferentially support the fundamental mode. VCSELs which exhibit greater than 3 mW of single mode output power at 850 nm with mode suppression ratio greater than 30 dB are reported.

CHOQUETTE,KENT D.; GEIB,KENT M.; BRIGGS,RONALD D.; ALLERMAN,ANDREW A.; HINDI,JANA JO

2000-04-26

197

Jamming of Cylindrical Grains in Featureless Vertical Channels  

NASA Astrophysics Data System (ADS)

We study jamming of low aspect-ratio cylindrical Delrin grains falling through a featureless vertical channel. With a grain height less than the grain diameter, these grains resemble aspirin tablets, poker chips, or coins. Unidisperse grains are allowed to fall under the influence of gravity through a uniform channel of square cross-section where the channel width is greater than the grain size and constant along the length of the channel. Channel widths are chosen so that no combination of grain heights and diameters is equal to the channel width. Collections of grains sometimes form jams, stable structures in which the grains are supported by the channel walls and not by grains or walls beneath them. The probability of a jam occurring and the jam's strength are influenced by the grain dimensions and channel width. We will present experimental measurements of the jamming probability and jam strength and discuss the relationship of these results to other experiments and theories.

Baxter, G. William; Barr, Nicholas; Weible, Seth; Friedl, Nicholas

2013-03-01

198

The Wake of a Single Vertical Axis Wind Turbine  

NASA Astrophysics Data System (ADS)

Vertical axis wind turbines (VAWTs) pose various advantages over traditional horizontal axis wind turbines (HAWTs), including their smaller size and footprint, quiet operation, and ability to produce power under a greater variety of wind directions and wind speeds. To determine the optimal spacing of an array of VAWTs for maximum power output, an understanding of the fundamental wake structure of a single VAWT is needed. This study is among the first attempts to experimentally visualize the wake of a VAWT using stereo particle image velocimetry (PIV). A scale VAWT is placed inside a wind tunnel and a motor rotates the scale model at a constant rotational speed. Wake data at several Reynolds numbers and tip speed ratios indicate that vortices are shed by each blade of the spinning VAWT, demonstrating significant differences between the wake of a VAWT and a spinning cylinder.

Barsky, Danielle

199

Fundamental and effective Yang-Mills vertices  

SciTech Connect

Calorons and plane waves within and in between them collectively give rise to a thermal ground state. The latter provides a homgeneous energy density and a negative pressure, and it induces quasiparticle masses to part of the propagating spectrum of deconfining SU(2) Yang-Mills thermodynamics (dynamical gauge-symmetry breaking). In the present talk we discuss the role of a single caloron in inducing effective local vertices, characterized by powers of h, mediating the interaction of plane waves which propagate over large distances. The constraints on momentum transfers through effective 4-vertices are revisited.

Hofmann, Ralf [ITP, Universitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)

2012-09-26

200

CIRSS vertical data integration, San Bernardino study  

NASA Technical Reports Server (NTRS)

The creation and use of a vertically integrated data base, including LANDSAT data, for local planning purposes in a portion of San Bernardino County, California are described. The project illustrates that a vertically integrated approach can benefit local users, can be used to identify and rectify discrepancies in various data sources, and that the LANDSAT component can be effectively used to identify change, perform initial capability/suitability modeling, update existing data, and refine existing data in a geographic information system. Local analyses were developed which produced data of value to planners in the San Bernardino County Planning Department and the San Bernardino National Forest staff.

Hodson, W.; Christenson, J.; Michel, R. (principal investigators)

1982-01-01

201

Concepts for generating optimum vertical flight profiles  

NASA Technical Reports Server (NTRS)

Algorithms for generating optimum vertical profiles are derived and examined. These algorithms form the basis for the design of onboard flight management concepts. The variations in the optimum vertical profiles (resulting from these concepts) due to variations in wind, takeoff weight, and range-to-destination are presented. Further considerations for mechanizing two different onboard methods of computing near-optimum flight profiles are then outlined. Finally, the results are summarized, and recommendations are made for further work. Technical details of optimum trajectory design, steering requirements for following these trajectories, and off-line computer programs for testing the concepts are included.

Sorensen, J. A.

1979-01-01

202

Developments in the Use of Proximity and Ratio Cues in Velocity Judgments.  

ERIC Educational Resources Information Center

Young children's responses to a velocity inference task based on static pictorial stimuli giving cues of proximity and ratio were examined. Subjects (N=65) in preschool through second grade viewed pictures of snails moving horizontally or spiders suspended vertically and were asked to estimate which competitor would reach its destination first.…

Shire, Beatrice; Durkin, Kevin

203

Integrality ratio for Group Steiner Trees and Directed Steiner Trees Eran Halperin  

E-print Network

Tree problem, as well as for its generalization, the Directed Steiner Tree problem, is a flow. For the Group Steiner Tree problem, we show the integrality ratio is (log2 k), where k denotes the number is tight. This also applies for the Directed Steiner Tree problem. In terms of the number n of vertices

Krauthgamer, Robert

204

Surface Area to Volume Ratio  

NSDL National Science Digital Library

This page contains two documents explaining surface area to volume ratio. The topic is covered at an advanced level in relation to nanotechnology and requires background knowledge in geometry, algebra, and linear and non-linear unit conversions. A powerpoint with illustrations and instructor guide (available as both a Microsoft Word Document and PDF) containing activities are included to aid in teaching this subject.

2012-10-16

205

Empirical Likelihood Ratio Confidence Regions  

Microsoft Academic Search

An empirical likelihood ratio function is defined and used to obtain confidence regions for vector valued statistical functionals. The result is a nonparametric version of Wilks' theorem and a multivariate generalization of work by Owen. Cornish-Fisher expansions show that the empirical likelihood intervals for a one dimensional mean are less adversely affected by skewness than are those based on Student's

Art Owen

1990-01-01

206

Rayleigh-Bénard convection with uniform vertical magnetic field  

NASA Astrophysics Data System (ADS)

We present the results of direct numerical simulations of Rayleigh-Bénard convection in the presence of a uniform vertical magnetic field near instability onset. We have done simulations in boxes with square as well as rectangular cross sections in the horizontal plane. We have considered the horizontal aspect ratio ? =Ly/Lx=1 and 2. The onset of the primary and secondary instabilities are strongly suppressed in the presence of the vertical magnetic field for ? =1. The Nusselt number Nu scales with the Rayleigh number Ra close to the primary instability as [{Ra-Rac(Q)}/Rac(Q)]0.91, where Rac(Q) is the threshold for onset of stationary convection at a given value of the Chandrasekhar number Q. Nu also scales with Ra/Q as (Ra/Q)?. The exponent ? varies in the range 0.39???0.57 for Ra/Q?25. The primary instability is stationary as predicted by Chandrasekhar. The secondary instability is temporally periodic for Pr =0.1 but quasiperiodic for Pr =0.025 for moderate values of Q. Convective patterns for higher values of Ra consist of periodic, quasiperiodic, and chaotic wavy rolls above the onset of the secondary instability for ? =1. In addition, stationary as well as time-dependent cross rolls are observed, as Ra is further raised. The ratio ro/Pr is independent of Q for smaller values of Q. The delay in the onset of the oscillatory instability is significantly reduced in a simulation box with ? =2. We also observe inclined stationary rolls for smaller values of Q for ? =2.

Basak, Arnab; Raveendran, Rohit; Kumar, Krishna

2014-09-01

207

Large current modulation in exfoliated-graphene/MoS2/metal vertical heterostructures  

NASA Astrophysics Data System (ADS)

Graphene-based vertical field effect transistors have attracted considerable attention in the light of realizing high-speed switching devices; however, the functionality of such devices has been limited by either their small ON-OFF current ratios or ON current densities. We fabricate a graphene/MoS2/metal vertical heterostructure by using mechanical exfoliation and dry transfer of graphene and MoS2 layers. The van der Waals interface between graphene and MoS2 exhibits a Schottky barrier, thus enabling the possibility of well-defined current rectification. The height of the Schottky barrier can be strongly modulated by an external gate electric field owing to the small density of states of graphene. We obtain large current modulation exceeding 105 simultaneously with a large current density of ˜104 A/cm2, thereby demonstrating the superior performance of the exfoliated-graphene/MoS2/metal vertical field effect transistor.

Moriya, Rai; Yamaguchi, Takehiro; Inoue, Yoshihisa; Morikawa, Sei; Sata, Yohta; Masubuchi, Satoru; Machida, Tomoki

2014-08-01

208

Air/fuel ratio regulator  

SciTech Connect

A description is given of an air/fuel ratio regulator for use with the fuel injection control system of an internal combustion engine of the spark ignition type having an air and exhaust gas (gas) induction passage open at one end to air at ambient pressure level and connected at its other end to the engine combustion chamber to be subject to manifold vacuum changes therein, a throttle valve rotatably mounted for movement across the passage to control the gas flow therethrough, exhaust gas recirculation (egr) passage means connecting engine exhaust gases to the induction passage above the closed position of the throttle valve, an egr flow control valve mounted in the egr passage means for movement between open and closed postions to control the volume of egr gas flow, an engine speed responsive positive displacement type fuel injection pump having a fuel flow output to the engine that varies in direct proportion to changes in engines speed to match fuel flow and mass airflow through the induction system of the engine over the entire speed and load range of the engine to maintain the intake mixture ratio of air to fuel constant, the pump having a fuel flow control lever movable to vary the fuel rate of flow, the regulator being characterized by engine manifold vacuum responsive first servo means operably connected to the fuel control lever for maintaining a constant air/fuel (A/F) ratio by changing fuel output as a function of changing manifold vacuum and air flow upon opening of the throttle valve, a fuel enrichment control lever operably connected to the pump control lever and movable to modify the position of the pump lever dictated by the first servo means to change the A/F ratio, and further means responsive to engine operating conditions for moving the fuel enrichment control lever to provide the changed A/F ratio.

Simko, A.

1980-07-22

209

Global Carbon Reservoir Oxidative Ratios  

NASA Astrophysics Data System (ADS)

Photosynthesis and respiration move carbon and oxygen between the atmosphere and the biosphere at a ratio that is characteristic of the biogeochemical processes involved. This ratio is called the oxidative ratio (OR) of photosynthesis and respiration, and is defined as the ratio of moles of O2 per moles of CO2. This O2/CO2 ratio is a characteristic of biosphere-atmosphere gas fluxes, much like the 13C signature of CO2 transferred between the biosphere and the atmosphere has a characteristic signature. OR values vary on a scale of 0 (CO2) to 2 (CH4), with most ecosystem values clustered between 0.9 and 1.2. Just as 13C can be measured for both carbon fluxes and carbon pools, OR can also be measured for fluxes and pools and can provide information about the processes involved in carbon and oxygen cycling. OR values also provide information about reservoir organic geochemistry because pool OR values are proportional to the oxidation state of carbon (Cox) in the reservoir. OR may prove to be a particularly valuable biogeochemical tracer because of its ability to couple information about ecosystem gas fluxes with ecosystem organic geochemistry. We have developed 3 methods to measure the OR of ecosystem carbon reservoirs and intercalibrated them to assure that they yield accurate, intercomparable data. Using these tools we have built a large enough database of biomass and soil OR values that it is now possible to consider the implications of global patterns in ecosystem OR values. Here we present a map of the natural range in ecosystem OR values and begin to consider its implications. One striking pattern is an apparent offset between soil and biospheric OR values: soil OR values are frequently higher than that of their source biomass. We discuss this trend in the context of soil organic geochemistry and gas fluxes.

Masiello, C. A.; Gallagher, M. E.; Hockaday, W. C.

2010-12-01

210

Role of vertical ion convection in the high-latitude ionospheric plasma distribution  

NASA Astrophysics Data System (ADS)

We use the Global Ionosphere-Thermosphere Model (GITM) to simulate the ionospheric reaction to a simple step change of the high-latitude forcing terms during the first hour of electric field enhancement. In response to the enhanced convection electric field, both the convection velocity and Joule heating increase dramatically. The changes in NmF2 present that the tongue extends across the polar cap and the troughs stretch longitudinally. The calculated total electron content (TEC) can vary by 15 TECU and have a similar pattern to the changes of NmF2. The changes in the vertical ion drift can be upward 100 m/s on the dayside and downward 100 m/s on the nightside as a consequence of the changes in the E × B drift. Approximately, hmF2 ascends where ViR is upward and descends where ViR is downward. In general, the response of the ionosphere to the enhanced E-field is that the F2 layer moves upward on the dayside and enhances at all altitudes on the nightside. Below the F2 peak (250 km altitude), the region of decreasing electron density coincides with the upward ViR on the dayside, and the reverse is true on the nightside. Above the F2 peak (450 km altitude), the features related with both horizontal convection and vertical advection are present. The vertical ion drift sets up a vertical circulation in the noon-midnight meridional plane during the early stage of E-field enhancement in addition to the widely accepted horizontal two cell convection. According to the circulation, the significant sources of tongue ionization are not only the plasma from the lower latitudes, but also from the low altitudes on the dayside. While the vertical circulation is not well organized after 6-hour E-field enhancement, the contribution of vertical ion convection is still significant. Although the vertical E × B drift in Apex coordinates is more complex and variable than that in a simple dipole magnetic field, the main characteristics are the same, which indicate the significance of the vertical circulation for the electron density distribution in reality during the early stage of E-field enhancement. The Joule heating drives upwelling of the atmosphere and modifies the O/N2 ratio. Meanwhile, the enhanced neutral advection twists the O/N2 ratio pattern a little bit. However, the changes in the O/N2 ratio have relatively poor correlation with the variation of electron density during the first hour of E-field enhanced time.

Deng, Y.; Ridley, A. J.

2006-09-01

211

Distribution and vertical dynamics of planktonic communities at Sofala Bank, Mozambique  

NASA Astrophysics Data System (ADS)

Coastal ecosystem processes are largely influenced by the interaction of different factors operating at various temporal and spatial scales, specifically those responsible for primary production patterns that modulate zooplankton and subsequent trophic levels. Hydrological processes, such as tidal cycles and coastal currents, nutrients availability, phytoplankton groups (studied through algal pigment signatures analysed by HPLC), and zooplankton abundance and distribution were investigated at the Sofala Bank (Mozambique), with special emphasis on their horizontal distribution and vertical dynamics (48 h). Horizontal distribution has shown inshore-offshore gradients in all analysed parameters, as well as inshore waters intrusion probably related to Zambezi River delta runoff. Tidal currents were responsible for major hydrological vertical variations and for horizontal and vertical advection of phytoplankton biomass in the surface and deepest layers, respectively. Nutrient concentrations were typical from oligotrophic regions, and nutrient ratios were strongly influenced by depleted nitrate + nitrite concentrations, indicating low estuarine discharges typical from the dry season. The very low N:P ratio obtained suggests strong nitrogen limitation to phytoplankton communities, supporting the low phytoplankton abundance observed. Both phytoplankton pigments and zooplankton were found mainly near the bottom (40 m depth), despite the latter displayed vertical migrations triggered by light variations. Phytoplankton community was dominated by microflagellates, specifically prymnesiophyceans, and behaved as a whole, except Cyanobacteria that displayed vertical distribution movements different from other phytoplankton groups, being mainly concentrated at mid-water column depths (10-20 m). This investigation enhances physico-chemical phenomena and their importance determining the planktonic communities vertical dynamics at Sofala Bank, a tropical coastal ecosystem of the Western Indian Ocean where planktonic dynamics are still poorly described and understood.

Leal, M. C.; Sá, C.; Nordez, S.; Brotas, V.; Paula, J.

2009-10-01

212

Vertical distribution of Pahang River plume  

NASA Astrophysics Data System (ADS)

Large rivers transported high amount of discharge towards the sea and induced the river plume formation. The contents of the plume consist of suspended solids, nutrients, pollutants and other particles. Productivity at estuary depends on the organic and nutrient contents from the river discharge. Due to many possible factors, the dispersal of the plume shows spatial variation horizontally and vertically. The monsoonal wind is a factor that effecting plume vertical profile pattern. This study determines the vertical distribution pattern of the plumeat Pahang River through field observation. Several water parameters were measured during cruises conducted at respective monsoon. Data collected includes depth, chlorophyll-a, salinity, temperature and suspended particulate matter. Depth at Pahang's offshore usually does not reached more than 15 m depth because of the shallow continental shelf at South China Sea. The plume has higher concentration at the mouth of the river which causes the area to be less saline and it decreases as the station furthers from the river. Chlorophyll-a is distributed mainly at the surface level where the area is warmer and received freshwater runoff. Suspended particulate matter shows downward distribution from the front of the estuary towards deep water column depth (10 m). Temperature pattern shows warmer surface layer with depth less than 5 m while deeper water column has lower temperature. Vertical profile pattern of Pahang River plume generally shows slight difference between each monsoon by referring to particular parameter.

Taher, T. M.; Lihan, T.; Mustapha, M. A.

2013-11-01

213

A Vertical Approach to Math Instruction  

ERIC Educational Resources Information Center

In the current era of mathematics standards, whether they are Common Core State Standards or other state standards, effective vertical mathematics teams offer an opportunity for teachers to grow professionally through shared experiences, for leadership to grow among the faculty, and for the school to change its perspective on the teaching and…

Gojak, Linda

2012-01-01

214

Vertical & Horizontal GHX's Advantages of Playing Together  

E-print Network

,000. Goldfield Oasis Leisure Centre, Kalgoorlie, WA Kalgoorlie, WA Goldfields Oasis Leisure Centre Perth Sydney Leisure Centre #12;4 Vertical & Horizontal GHX's Advantages of Playing Together IGSHPA Conference competitive pool and large leisure pool. In the last few years cost of electricity has increased

215

Vertical transmission of hepatitis E virus  

Microsoft Academic Search

Little is known about vertical transmission of hepatitis E virus from infected mothers to their infants. We studied eight babies born to mothers infected with hepatitis E in third trimester. One baby was icteric at birth with elevated transaminases and four babies had anicteric hepatitis. Two babies were born with hypothermia and hypoglycaemia and died within 24 h; one had

M. S. Khuroo; S. Kamali; S. Jameel

1995-01-01

216

Early surgical treatment for congenital vertical talus  

Microsoft Academic Search

Congenital vertical talus is characterised by a dislocated talonavicular joint in association with an equinus position of the calcaneus. We report the results in 13 operated feet in 10 children, 3 of whom (5 feet) presented with a primary neurological disorder and 2 of whom (3 feet) suffered from arthrogryposis multiplex congenita. The other children were normal. All patients were

T. Wirth; P. Schuler; P. Griss

1994-01-01

217

Brand Equity and Vertical Product Line Extent  

Microsoft Academic Search

This paper addresses the question of how the vertical structure of a product line relates to brand equity. Does the presence of “premium” or high-quality products in a product line enhance brand equity? Conversely, does the presence of “economy” or low-quality products in a product line diminish brand equity? Economists and marketing researchers refer to variation in quality levels of

Taylor Randall; Karl Ulrich; David Reibstein

1998-01-01

218

Vertically aligned biaxially textured molybdenum thin films  

NASA Astrophysics Data System (ADS)

Vertically aligned, biaxially textured molybdenum nanorods were deposited using dc magnetron sputtering with glancing flux incidence (alpha = 85° with respect to the substrate normal) and a two-step substrate-rotation mode. These nanorods were identified with a body-centered cubic crystal structure. The formation of a vertically aligned biaxial texture with a [110] out-of-plane orientation was combined with a [-110] in-plane orientation. The kinetics of the growth process was found to be highly sensitive to an optimum rest time of 35 seconds for the two-step substrate rotation mode. At all other rest times, the nanorods possessed two separate biaxial textures each tilted toward one flux direction. While the in-plane texture for the vertical nanorods maintains maximum flux capture area, inclined Mo nanorods deposited at alpha = 85° without substrate rotation display a [-1-1-4] in-plane texture that does not comply with the maximum flux capture area argument. Finally, an in situ capping film was deposited with normal flux incidence over the biaxially textured vertical nanorods resulting in a thin film over the porous nanorods. This capping film possessed the same biaxial texture as the nanorods and could serve as an effective substrate for the epitaxial growth of other functional materials.

Krishnan, Rahul; Riley, Michael; Lee, Sabrina; Lu, Toh-Ming

2011-09-01

219

Higher Education Vertical Infrastructure Maintenance Planning.  

ERIC Educational Resources Information Center

To assist higher education facility officers in documenting their financial needs for renewing and renovating existing physical facilities, this study examined the accuracy against observed conditions of the tools used to identify vertical infrastructure maintenance needs in a large public university. Data developed for U.S. Army facilities is…

Weidner, Theodore J.

220

Lightning Performance of Vertical Antenna Ground Systems  

Microsoft Academic Search

Most vertical antennas used in the AM standard broadcast band in the United States have extensive radial ground systems beneath them which serve as image planes. These same image planes can function as excellent ground systems for dissipating lightning discharges. When subjected to a lightning stroke, the \\

Alan Christman

1979-01-01

221

Printed millimeter wave vertical patch antenna  

Microsoft Academic Search

A new form of millimeter wave antenna element by embedding a vertical patch antenna into a microwave substrate is presented. The antenna is fed by the special grounded CPW\\/microstrip\\/printed ring combination. An air cavity is employed to enhance the antenna gain. The designed antenna is ease of fabrication and the simple in structure. It has an impedance bandwidth of 26%

Hang Wong; Kung Bo Ng; Kwai Man Luk; Chi Hou Chan; Quan Xue

2010-01-01

222

Optimum Current Distributions on Vertical Antennas  

Microsoft Academic Search

The theoretical optimum current distribution on a vertical antenna of given length is defined as that current distribution giving the maximum possible field strength on the horizon for a given power output. The problem of determining such distributions is set up as a problem in the calculus of variations, and solution functions are derived for antennas varying in length from

G. A. Miller

1943-01-01

223

Vertical boring mill capacity is increased  

NASA Technical Reports Server (NTRS)

Commercially available vertical boring mill with a nominal capacity to 27 feet in diameter of workpiece has been modified in-shop to handle work up to 36 feet in diameter. Capacity was increased by adding extension saddles to the mill support columns on each side.

Young, R. J.

1968-01-01

224

Vertical distribution of Titan's atmospheric neutral constituents  

Microsoft Academic Search

The vertical distribution of Titan's neutral atmosphere compounds is calculated from a new photochemical model extending from 40 to 1432 km. This model makes use of many updated reaction rates, and of the new scheme for methane photolysis proposed by Mordaunt et al. [1993]. The model also includes a realistic treatment of the dissociation of N2, of the deposition of

L. M. Lara; E. Lellouch; J. J. López-Moreno; R. Rodrigo

1996-01-01

225

The Teleostean Swimbladder and Vertical Migration  

Microsoft Academic Search

IT has been suggested by several authors1-6 that the vertical movements of a teleost would be restricted by the presence of a swimbladder which will increase or decrease in volume when the fish moves up or down in the water. Fishes taken by line or trawl often arrive at the surface visibly distended, when they are said to be `blown'.

F. R. H. Jones

1949-01-01

226

On the Design of Vertical Hydraulic Fractures  

Microsoft Academic Search

Some of the assumptions involved in designing vertical hydraulic fractures should be critically examined as to their validity. This is done on the basis of a new width equation and a numerical design procedure. It is found that some of the assumptions related to the fluid mechanics of the problem greatly affect the computed results and therefore deserve special attention.

Abbas Daneshy

1973-01-01

227

[From vertical to horizontal. Writing in adolescence].  

PubMed

Writing at adolescence has a non negligible part in identity's construction. Vertical writing as tags, graphs and graffiti refer to a narcissism deficiency and express a pulsional necessity, whereas, horizontal writing as private diaries, letters and novels express object's search and are made in dreaming attitude. PMID:7618823

Catheline-Antipoff, N

1995-04-01

228

Bundling in Vertically Differentiated Communication Markets  

Microsoft Academic Search

We look at the competition and the welfare effects of bundling in the context of vertically differentiated communication services (Television, Telephone and Internet). We consider a two- stage game with two asymmetric firms. In the first stage firms simultaneously commit to adopt bundling or component pricing. These decisions give four possible configurations: (i) a configuration where both firms use component

Thierno Diallo

229

Host Country Educational Attainment and Vertical Specialization  

Microsoft Academic Search

Integration of the global economy through trade has enabled firms to adopt new production strategies. Rather than producing in a single country, stages of production are performed in multiple countries to exploit inherent locational advantages. This practice gives rise to vertical specialization across national boundaries. Here, the U.S. exports components to a foreign (host) country that uses them to produce

Don P. Clark

2008-01-01

230

Modifications in vertical scar breast reduction  

Microsoft Academic Search

The use of vertical-scar breast reduction techniques is only slowly increasing, even though they have been advocated by Lassus and Lejour and are requested by patients. Possible reasons why surgeons are reluctant to use these techniques are that they are said to be more difficult to learn, they require considerable experience and intuition, and their applicability is confined to small

G. M. Beer; W. Morgenthaler; I. Spicher; V. E. Meyer

2001-01-01

231

Vertical motions in the equatorial middle atmosphere  

NASA Technical Reports Server (NTRS)

A single station vertical velocity equation which considers ageostrophic and diabatic effects derived from the first law of thermodynamics and a generalized thermal wind relation is presented. An analysis and verification procedure which accounts for measurement and calculation errors as well as time and space continuity arguments and theoretical predictions are described. Vertical velocities are calculated at every kilometer between 25 and 60 km and for approximately every three hours for the above diurnal period at Kourou (French Guiana), Fort Sherman (Panama Canal Zone), Ascension Island, Antigua (British West Indies) and Natal (Brazil). The results, plotted as time series cross sections, suggest vertical motions ranging in magnitude from 1 or 2 cm/sec at 30 km to as much as 15 cm/sec at 60 km. Many of the general features of the results agree well with atmospheric tidal predictions but many particular features suggest that both smaller time scale gravity waves (periods less than 6 hours) and synoptic type waves (periods greater than 1 day) may be interacting significantly with the tidal fields. The results suggest that vertical motions can be calculated for the equatorial middle atmosphere and must be considered a significant part of the motion for time scales from 8 to 24 hours.

Weisman, M. L.

1979-01-01

232

Vertical root fractures and their management  

PubMed Central

Vertical root fractures associated with endodontically treated teeth and less commonly in vital teeth represent one of the most difficult clinical problems to diagnose and treat. In as much as there are no specific symptoms, diagnosis can be difficult. Clinical detection of this condition by endodontists is becoming more frequent, where as it is rather underestimated by the general practitioners. Since, vertical root fractures almost exclusively involve endodontically treated teeth; it often becomes difficult to differentiate a tooth with this condition from an endodontically failed one or one with concomitant periodontal involvement. Also, a tooth diagnosed for vertical root fracture is usually extracted, though attempts to reunite fractured root have been done in various studies with varying success rates. Early detection of a fractured root and extraction of the tooth maintain the integrity of alveolar bone for placement of an implant. Cone beam computed tomography has been shown to be very accurate in this regard. This article focuses on the diagnostic and treatment strategies, and discusses about predisposing factors which can be useful in the prevention of vertical root fractures. PMID:24778502

Khasnis, Sandhya Anand; Kidiyoor, Krishnamurthy Haridas; Patil, Anand Basavaraj; Kenganal, Smita Basavaraj

2014-01-01

233

Analysis of vertical precipitation characteristics using by Vertical Pointing Radar and Optical Disdrometer in Korea  

NASA Astrophysics Data System (ADS)

The objective of this study is to understand the vertical precipitation structure by using the vertical pointing radar (MRR, Micro Rain Radar, OTT Inc.) and optical disdrometer (PARSIVEL, PARticle SIze and VELocity, METEK Inc.) set, established in the coastal and mountainous regions of South Korea. The observational factors measured by both instruments are precipitation drop size distribution (DSD), rain rate, and liquid water content. The MRR's DSD at its low level shows good agreement with that of PARSIVEL. We retrieve the vertical rain rate and liquid water content from MRR under melting layer, calculated by Cha et al's method, in Daegwallyeong (37°41' N,128°45' E, 843 m ASL, mountain area) and Haenam (34°33' N,126°34' E, 4.6 m ASL, coast area). The vertical variations of rain rate and liquid water content in Daegwallyeong are smaller than those in Haenam. We think that this different vertical rain rate characteristic for both sites is due to the vertical different cloud type (convective and stratiform cloud seem dominant at Haenam and Daegwallyeong, respectively). This suggests that the statistical precipitation DSD model, for the application of weather radar and numerical simulation of precipitation processes, be considered differently for the region. More detailed analysis of vertical DSD and microphysical structure of precipitation measured by MRR will be presented at the conference.

cha, J.; Chang, K.; Choi, Y.; Yum, S. S.

2011-12-01

234

Optic disc boundary segmentation from diffeomorphic demons registration of monocular fundus image sequences versus 3D visualization of stereo fundus image pairs for automated early stage glaucoma assessment  

NASA Astrophysics Data System (ADS)

Despite the current availability in resource-rich regions of advanced technologies in scanning and 3-D imaging in current ophthalmology practice, world-wide screening tests for early detection and progression of glaucoma still consist of a variety of simple tools, including fundus image-based parameters such as CDR (cup to disc diameter ratio) and CAR (cup to disc area ratio), especially in resource -poor regions. Reliable automated computation of the relevant parameters from fundus image sequences requires robust non-rigid registration and segmentation techniques. Recent research work demonstrated that proper non-rigid registration of multi-view monocular fundus image sequences could result in acceptable segmentation of cup boundaries for automated computation of CAR and CDR. This research work introduces a composite diffeomorphic demons registration algorithm for segmentation of cup boundaries from a sequence of monocular images and compares the resulting CAR and CDR values with those computed manually by experts and from 3-D visualization of stereo pairs. Our preliminary results show that the automated computation of CDR and CAR from composite diffeomorphic segmentation of monocular image sequences yield values comparable with those from the other two techniques and thus may provide global healthcare with a cost-effective yet accurate tool for management of glaucoma in its early stage.

Gatti, Vijay; Hill, Jason; Mitra, Sunanda; Nutter, Brian

2014-03-01

235

Vertical Acoustic Arrays in the Deep Ocean  

NASA Astrophysics Data System (ADS)

The R/P FLIP has made possible the deployments of vertical arrays to study sound propagation and ambient noise in the deep ocean in ways never before possible from existing research vessels. Long vertical arrays can be deployed without the flow noise contamination from platform motion, long a bane for making such studies. The vertical stability of FLIP combined with the deep mooring capability developed by Earl D. Bronson made it possible to deploy multi-element arrays beginning with a versatile 20 element array with variable spacing developed by Bill Whitney in Fred Spiess's group. The 20 element array consisted of bungee mounted hydrophones in metal cages at either uniform spacing or variable spacing to meet directivity or other requirements. It was assembled on station in the vertical and deployed to the desired depths for the elements. Gerald Morris at MPL conducted ambient noise studies using variable spacing of the elements to below the critical depth as well as in the water column above. Vic Anderson used it for his DIMUS processing system for detecting low level signals masked by ambient noise. As a 500 meter array, I used it for a series of CONTRACK (Continuous Tracking of signals at long range) experiments to resolve multipaths so they wouldn't interfere with one another. The VEKA vertical array developed by Rick Swenson of NORDA was deployed in very deep (below 3300 m) water by Dan Ramsdale of NORDA using the winch and double lay armored cable on FLIP, the same cable system for the MPL 20 element array. In my group Bruce Williams designed a rapidly deployable array to study vertical anisotropy of ambient noise as a function of range from near shore shipping via downslope conversion in a series of 48 hours FLIP stations 350, 1000 and 1500 miles from the Pacific coast. A short 120 element array, 1000 meters long, was built by John Hildebrands's group for a test of matched field processing and the SLICE experiment in acoustic tomography research of Peter Worcester and Walter Munk in 1987. Later a different 200 element array over 3000 meters long was also built by John Hildebrand's group for deloyment in the VAST experiment in 1987. This array included acoustic navigation to measure element location for several different experiments including matched field processing at 1000 km, normal mode studies and down-slope conversion of shipping noise and by Stan Flatte of UCSC for looking at long range barotropic wave reflections from Alaska. In a separate talk, Gerald D'Spain will discuss a trifar (3D) vertical array developed at MPL.

Fisher, F.

2002-12-01

236

Project Plan for Vertical Lift Machine  

SciTech Connect

This document describes the Project Plan for the development and manufacture of a Vertical Lift Machine. It is assumed by this project plan that the Vertical Lift Machine will be developed, designed, manufactured, and tested by a qualified vendor. LLNL will retain review and approval authority for each step given in this project plan. The Vertical Lift Machine is a single linear axis positioning device capable of lifting objects vertically at controlled rates and positioning them repeatedly at predetermined heights, in relation to other objects suspended from above, for high neutron multiplication experiments. Operation of the machine during the experiments is done remotely. The lift mechanism shall accommodate various platforms (tables) that support the objects to be raised. A frame will support additional subassemblies from above such that the lower subassembly can be raised close to and/or interface with those above. The structure must be stiff and motion of the table linear such that radial alignment is maintained (e.g. concentricity). The safe position for the Vertical Lift Machine is the lift mechanism fully retracted with the subassemblies fully separated. The machine shall reside in this position when not in use. It must return to this safe condition from any position upon failure of power sources, open safety interlocks, or operator initiated SCRAM. The Vertical Lift Machine shall have the capability of return to the safe position with no externally applied power. The Vertical Lift Machine shall have dual operator interfaces, one near the machine and another located in a remote control room. Conventional single key, key-lock switching shall be implemented to lock out the control interface not in use. The interface at the machine will be used for testing and ''dry running'' experimental setup(s) with inert subassemblies (i.e. Setup Mode). The remote interface shall provide full control and data recording capability (i.e. Assembly Mode). The control system will be a combination of Programmable Logic Controller (PLC), or equivalent, and relay logic. The operator shall have the ability to adjust lift/lower velocity and position of the table. All measurements will be made as close to, and in line with, the axis of motion as practical. Measurement data, system parameter information, and interlock status shall be displayed.

Ellsworth, G F

2002-08-05

237

GUT Scale Fermion Mass Ratios  

NASA Astrophysics Data System (ADS)

We present a series of recent works related to group theoretical factors from GUT symmetry breaking which lead to predictions for the ratios of quark and lepton Yukawa couplings at the unification scale. New predictions for the GUT scale ratios y?/ys, y?/yb and yt/yb in particular are shown and compared to experimental data. For this comparison it is important to include possibly large supersymmetric threshold corrections. Due to this reason the structure of the fermion masses at the GUT scale depends on TeV scale physics and makes GUT scale physics testable at the LHC. We also discuss how this new predictions might lead to predictions for mixing angles by discussing the example of the recently measured last missing leptonic mixing angle ?13 making this new class of GUT models also testable in neutrino experiments.

Spinrath, Martin

2014-10-01

238

Diffusive Layering in Large and Small Aspect-Ratio Containers  

NASA Astrophysics Data System (ADS)

The diffusive interface of double-diffusive staircases is investigated using laboratory experiments and theoretical modeling. Heat/salt and petrochemical (stimulant oil)/heat mixtures are considered, with applications to oceanographic and engineering (e.g. Strategic Petroleum Reserves) flows. The goals were to study how the convective layers above the first layer can be scaled for large aspect ratio (width/height) configurations; delineate conditions under which adjoining convective layers merge; and propose scaling for layer heights for small aspect ratio cases. In the experiments a stable solute gradient is heated from below, forming multiple convective layers separated by diffusive interfaces, and the evolution of temperature and density profiles as well as velocity fields are measured. The theoretical layer heights are derived based on the argument that convective layers grow until their vertical growth is inhibited by a balance between the vertical inertia forces of convective eddies and stable buoyancy forces of diffusive interfaces. Comparisons of experimental and theoretical results are made.

Pol, S. U.; Fernando, H. J. S.; Webb, S.

2007-11-01

239

The ZH ratio method for long-period seismic data: sensitivity kernels and observational techniques  

NASA Astrophysics Data System (ADS)

Amplitude ratio between vertical and horizontal components of Rayleigh waves is controlled by structure beneath a seismic station. This ratio, measured as a function of frequency, has been extensively analysed for shallow crustal structure study in earthquake engineering and applied seismology. This quantity, termed the ZH ratio in this paper, may be useful for deep earth structure study and its feasibility for the frequency range between 0.004 and 0.05 Hz (period 20-250 s) is explored in this paper. For depth sensitivity kernels, we demonstrate that a numerical approach is practical and provides sufficient accuracy for structural inversion. Depth extent of sensitivity kernels are about half of depth extent in phase velocity kernels, indicating that the ZH ratio is useful for studying the lithospheric structure. Two observational approaches for measurement of the ZH ratio are presented; the first approach uses simple envelope amplitude ratio and the second approach uses waveform correlation technique between vertical and horizontal components. The ZH ratio data alone only constrains structure beneath seismic stations but recent densification of seismic networks may make it possible to extend the analysis to regional scale structure. A greater opportunity may exist in combination of the ZH ratio method and the phase and group velocity measurements.

Tanimoto, T.; Rivera, L.

2008-01-01

240

The midbrain to pons ratio  

PubMed Central

Objectives: MRI-based measurements used to diagnose progressive supranuclear palsy (PSP) typically lack pathologic verification and are not easy to use routinely. We aimed to develop in histologically proven disease a simple measure of the midbrain and pons on sagittal MRI to identify PSP. Methods: Measurements of the midbrain and pontine base on midsagittal T1-weighted MRI were performed in confirmed PSP (n = 12), Parkinson disease (n = 2), and multiple system atrophy (MSA) (n = 7), and in controls (n = 8). Using receiver operating characteristic curve analysis, cutoff values were applied to a clinically diagnosed cohort of 62 subjects that included PSP (n = 21), Parkinson disease (n = 10), MSA (n = 10), and controls (n = 21). Results: The mean midbrain measurement of 8.1 mm was reduced in PSP (p < 0.001) with reduction in the midbrain to pons ratio (PSP smaller than MSA; p < 0.001). In controls, the mean midbrain ratio was approximately two-thirds of the pontine base, in PSP it was <52%, and in MSA the ratio was greater than two-thirds. A midbrain measurement of <9.35 mm and ratio of 0.52 had 100% specificity for PSP. In the clinically defined group, 19 of 21 PSP cases (90.5%) had a midbrain measurement of <9.35 mm. Conclusions: We have developed a simple and reliable measurement in pathologically confirmed disease based on the topography of atrophy in PSP with high sensitivity and specificity that may be a useful tool in the clinic. PMID:23616165

Massey, Luke A.; Jager, Hans R.; Paviour, Dominic C.; O'Sullivan, Sean S.; Ling, Helen; Williams, David R.; Kallis, Constantinos; Holton, Janice; Revesz, Tamas; Burn, David J.; Yousry, Tarek; Lees, Andrew J.; Fox, Nick C.; Micallef, Caroline

2013-01-01

241

Stable Isotope Ratios: Hurricane Olivia  

Microsoft Academic Search

The oxygen and hydrogen isotopic compositions of rains from HurricaneOlivia (1994) in the eastern Pacific were measured. The rains werecollected on 24 and 25 September during airplane flights conducted at anelevation of 3 km. Hurricane Olivia peaked in intensity to a category-4storm between the two dates. Isotope ratios of rains from HurricaneOlivia were markedly lower (d 18O = –13.9‰to –28.8‰)

James R. Lawrence; Stanley David Gedzelman; John Gamache; Michael Black

2002-01-01

242

The golden ratio autocorrelation function  

E-print Network

On the base of the recurrence relation formalism an autocorrelation function is obtained, the continued fraction form of which corresponds to the golden ratio ones. It turns out that this GR autocorrelation is known in science and obeys all necessary conditions, in contrast to the exponential autocorrelation function. Using the Kubo approach it is shown how exponential correlations appear in the linear response theory as a result on non-Hermitian relaxation of the system.

R. Tsekov

2014-02-10

243

Modifications in vertical scar breast reduction.  

PubMed

The use of vertical-scar breast reduction techniques is only slowly increasing, even though they have been advocated by Lassus and Lejour and are requested by patients. Possible reasons why surgeons are reluctant to use these techniques are that they are said to be more difficult to learn, they require considerable experience and intuition, and their applicability is confined to small breasts. Several surgeons have developed modifications, combining vertical-scar breast reduction techniques with details of the familiar inverted-T-scar technique. We present a procedure involving two further modifications of the vertical-scar breast reduction technique: first, a standardised, geometrical preoperative drawing from our superior-pedicle T technique, with the aim of establishing a reproducible method of reduction requiring no particular intuitive touch, and, second, the addition of a periareolar skin resection, to give the breast the desired round shape. Between September 1998 and December 1999 we used this technique in a prospective series of 52 patients. The median resection weight was 450 g. The maximal postoperative follow-up was 15 months. There were no acute postoperative complications necessitating reoperation. The late complication rate was within the expected range for such procedures (seven patients, 13.5%) and included vertical-scar widening, areolar distortion, residual wrinkles due to incomplete shrinkage of the undermined skin in the inferior pole and asymmetry of the breast. This procedure enables us to offer patients with moderate to marked hypertrophy a reproducible versatile vertical breast reduction technique. The technique is easy to teach and easy to learn, especially for those who are familiar with the superior pedicle inverted-T-scar technique. PMID:11355991

Beer, G M; Morgenthaler, W; Spicher, I; Meyer, V E

2001-06-01

244

Highly ordered vertical GaAs nanowire arrays with dry etching and their optical properties  

NASA Astrophysics Data System (ADS)

We report fabrication methods, including metal masks and dry etching, and demonstrate highly ordered vertical gallium arsenide nanowire arrays. The etching process created high aspect ratio, vertical nanowires with insignificant undercutting from the mask, allowing us to vary the diameter from 30 nm to 400 nm with a pitch from 250 nm to 1100 nm and length up to 2.2 ?m. A diameter to pitch ratio of ˜68% was achieved. We also measured the reflectance from the nanowire arrays and show experimentally diameter-dependent strong absorption peaks resulting from resonant optical mode excitations within these nanowires. The reflectance curves match very well with simulations. The work done here paves the way towards achieving high efficiency solar cells and tunable photodetectors using III-V nanowires.

Dhindsa, Navneet; Chia, Andrew; Boulanger, Jonathan; Khodadad, Iman; LaPierre, Ray; Saini, Simarjeet S.

2014-08-01

245

Highly ordered vertical GaAs nanowire arrays with dry etching and their optical properties.  

PubMed

We report fabrication methods, including metal masks and dry etching, and demonstrate highly ordered vertical gallium arsenide nanowire arrays. The etching process created high aspect ratio, vertical nanowires with insignificant undercutting from the mask, allowing us to vary the diameter from 30 nm to 400 nm with a pitch from 250 nm to 1100 nm and length up to 2.2 ?m. A diameter to pitch ratio of ?68% was achieved. We also measured the reflectance from the nanowire arrays and show experimentally diameter-dependent strong absorption peaks resulting from resonant optical mode excitations within these nanowires. The reflectance curves match very well with simulations. The work done here paves the way towards achieving high efficiency solar cells and tunable photodetectors using III-V nanowires. PMID:25008170

Dhindsa, Navneet; Chia, Andrew; Boulanger, Jonathan; Khodadad, Iman; LaPierre, Ray; Saini, Simarjeet S

2014-08-01

246

A methodology for evaluation of vertical dispersion and dry deposition of atmospheric aerosols  

NASA Astrophysics Data System (ADS)

A new approach to treatment of vertical dispersion and dry deposition of atmospheric aerosols is suggested for primary application in mesoscale to global atmospheric transport models. The vertical exchange scheme extends the resistance analogy formulated earlier for gaseous species and fine aerosols. The approach is based on the exact solution of the steady-state equation for aerosol flux within a finite layer. The flux is expressed as a linear function of concentrations at the layer boundaries and accounts for the vertical inhomogeneity of the diffusion coefficient and the regular vertical velocity. The new dry deposition scheme accounts for physical properties of the air flow, surface and depositing particles. The flow is given by the vertical profile of exchange coefficient and characteristic velocity at the surface. The deposition rate to smooth surfaces is obtained via solution of the budget equation for particle mass. The transition from smooth to rough flow regime is considered. Rough surfaces are characterized by two length scales: the aerodynamic roughness and the "collection scale", introduced in this paper. The collection scale incorporates the effective size of collectors and a ratio of the airflow velocity at the top of the roughness elements to the friction velocity. The particles are described by their physical size, relaxation time and Brownian diffusivity. The scheme was developed basing exclusively on wind-tunnel and numerical experiments available from the literature, and reproduces them well. The data of outdoor experiments have noticeably larger uncertainties, which allowed only general evaluation of their agreement with the predictions.

Kouznetsov, Rostislav; Sofiev, Mikhail

2012-01-01

247

Chimney effect due to different vertical position of an isothermal horizontal cylinder confined between two adiabatic walls  

SciTech Connect

The variation of natural convection heat transfer from an isothermal horizontal cylinder confined between two adiabatic walls of constant height is investigated by Mach-Zehnder interferometry technique. This paper focuses on the chimney effect due to the vertical position changes of cylinder (Y) located between two walls with a constant distance of W measuring 1.5 cylinder diameter. The cylinder's local and average Nusselt numbers are determined for ratio of vertical position to its diameter ranging from Y/D = (0 to 10), and the Rayleigh number ranging from 3.5 x 10{sup 3} to 1.4 x 10{sup 4}. There is an optimum distance between the walls in which the Nusselt number is maximum. Results are indicated with a single correlation which gives the average Nusselt number as a function of the ratio of vertical position to cylinder diameter and the Rayleigh number. The experimental data shows that there is an optimum vertical position for the cylinder at which the Nusselt number has a maximum value at each Rayleigh number. This optimal vertical position is derived from the correlation and is presented by an equation. The value of the optimum vertical position increases as the Rayleigh number increases. (author)

Harsini, Iraj; Ashjaee, Mehdi [Mechanical Engineering Department, University of Tehran, Tehran (Iran)

2009-04-15

248

Propagation delay dependence on channel fins and geometry aspect ratio of 16-nm multi-gate MOSFET inverter  

Microsoft Academic Search

Fin-type vertical channel field effect transistors (FETs) are promising alternatives for the sub-32-nm CMOS technologies. This work investigates the impact of fin number and structure on Vth degradation and transient behavior of devices and circuits. Vertical channel transistors with different fin aspect ratio (AR = the fin height \\/ the effective fin width) are explored. The multi-fin FinFETs (AR =

Hui-Wen Cheng; Chih-Hong Hwang; Yiming Li

2009-01-01

249

A vertically-pointing Doppler radar to measure precipitation characteristics in the tropics  

Microsoft Academic Search

Describes the design and preliminary results from a vertically-pointing pulsed S-band Doppler radar, capable of measuring reflectivity (dBZ), linear depolarization ratio (LDR), and the Doppler spectrum. The data reported were acquired during a short experimental campaign while the radar was sited in Southern UK. The system has now been sent to Papua New Guinea for a 12 month programme of

J. D. Eastment; M. Thurai; D. N. Ladd; I. N. Moore

1995-01-01

250

Optical logic gates based on integrated vertical cavity laser with depleted optical thyristor structure  

Microsoft Academic Search

Optical switches and optical logic gates with AND and OR functionality are demonstrated by the monolithic integration of a vertical cavity lasers with depleted optical thyristor structure. The thyristors have a low threshold current of 0.65 mA and a high on\\/off contrast ratio of more than 50 dB. By simply changing a reference switching voltage, this single device operates as

Woonkyung Choi; Doo-Gun Kim; Yon-Tae Moon; Young-Wan Choi; Seok Lee; Deok-Ha Woo; Young-Min Jhon; Young-Tae Byun

2006-01-01

251

Natural convection in a vertical porous cavity: A numerical study for Brinkman-extended Darcy formulation  

Microsoft Academic Search

A dimensional analysis of the Brinkman-extended Darcy formulation, which includes the transport and viscous terms, leads to four governing parameters for steady-state natural convection in a vertical porous cavity. They are: Rayleigh number, Darcy number, diffusion parameter Ω, and aspect ratio. Numerical results for 0 ⤠Da ⤠10⁻¹, 10 ⤠Ra* ⤠5 à 10³, and A = 1

G. Lauriat; V. Prasad

1987-01-01

252

The design, construction, testing and manufacturing of vertical axis wind turbines  

Microsoft Academic Search

The design, construction and testing of a 17-meter Darrieus type vertical axis wind turbine (VAWT) are described, and results of a performance-cost optimation study and manufacturing studies of VAWTs are presented. Two- and three-blade rotor configurations have been tested. The blades are troposkein-shaped, with a symmetrical airfoil cross section developed from helicopter-blade technology. The power train has 13 gear-ratio settings

R. H. Braasch

1978-01-01

253

The vertical-mill stage : design of a vertical movement stage for surface machining  

E-print Network

To allow the widespread use of three dimensional patterns on walls, the manufacturing cost must be reduced. The goal of this project is to design a machine for vertical axis movement which can be measured and controlled. ...

Herrera, Juan, Jr

2007-01-01

254

Nation's tallest VAWT (Vertical Axis Wind Turbine) turning out the watts. [Vertical Axis Wind Turbine  

SciTech Connect

This article describes the development of the tallest and most powerful windmill of its kind in the U.S. Known as a Vertical Axis Wind Turbine (VAWT), the machine is meant for testing new concepts in vertical axis turbine design. As part of its overall testing program, the turbine will supply electricity to automated water pumps used in irrigation research at the Research Laboratory in Bushland, Texas. Excess power will go to the Southwestern Public Service Company for the area power system.

Miller, S.

1988-05-01

255

CRISTA-NF measurements with unprecedented vertical resolution during the RECONCILE aircraft campaign  

NASA Astrophysics Data System (ADS)

The Cryogenic Infrared Spectrometers and Telescope for the Atmosphere - New Frontiers (CRISTA-NF), an airborne infrared limb-sounder, was operated aboard the high-flying Russian research aircraft M55-Geophysica during the Arctic RECONCILE campaign from January to March 2011. This paper describes the calibration process of the instrument and the employed retrieval algorithm and then proceeds to present retrieved trace gas mixing ratio cross-sections for one specific flight of this campaign. We are able to resolve the uppermost troposphere/lower stratosphere for several trace gas species for several kilometres below the flight altitude (16 to 19 km) with an unprecedented vertical resolution of 400 to 500 m for the limb-sounding technique. The observations are also characterised by a rather high horizontal sampling along the flight track that provides a full vertical profile every ?15 km. Assembling the vertical trace gas profiles derived from CRISTA-NF measurements to cross-sections depicts filaments of vortex and extra-vortex air masses in the vicinity of the polar vortex. During this campaign, the M55-Geophysica carried further instruments, which allows for a validation of trace gas mixing ratios derived from CRISTA-NF against measurements by the in situ instruments HAGAR and FOZAN and observations by MIPAS-STR. This validation suggests that the retrieved trace gas mixing ratios are both qualitatively and quantitatively reliable.

Ungermann, J.; Kalicinsky, C.; Olschewski, F.; Knieling, P.; Hoffmann, L.; Blank, J.; Woiwode, W.; Oelhaf, H.; Hösen, E.; Volk, C. M.; Ulanovsky, A.; Ravegnani, F.; Weigel, K.; Stroh, F.; Riese, M.

2011-11-01

256

CRISTA-NF measurements with unprecedented vertical resolution during the RECONCILE aircraft campaign  

NASA Astrophysics Data System (ADS)

The Cryogenic Infrared Spectrometers and Telescope for the Atmosphere - New Frontiers (CRISTA-NF), an airborne infrared limb-sounder, was operated aboard the high-flying Russian research aircraft M55-Geophysica during the Arctic RECONCILE campaign from January to March 2010. This paper describes the calibration process of the instrument and the retrieval algorithm employed and then proceeds to present retrieved trace gas volume mixing ratio cross-sections for one specific flight in this campaign. We are able to resolve the uppermost troposphere/lower stratosphere for several trace gas species for several kilometres below the flight altitude (16 to 19 km) with an unprecedented vertical resolution of 400 to 500 m for the limb-sounding technique. The instrument points sideways with respect to the flight direction. Therefore, the observations are also characterised by a rather high horizontal sampling along the flight track, which provides a full vertical profile every ?15 km. Assembling the vertical trace gas profiles derived from CRISTA-NF measurements to cross-sections shows filaments of vortex and extra-vortex air masses in the vicinity of the polar vortex. During this campaign, the M55-Geophysica carried further instruments enabling trace gas volume mixing ratios derived from CRISTA-NF to be validated by comparing them with measurements by the in situ instruments HAGAR and FOZAN and observations by MIPAS-STR. This validation suggests that the retrieved trace gas volume mixing ratios are both qualitatively and quantitatively reliable.

Ungermann, J.; Kalicinsky, C.; Olschewski, F.; Knieling, P.; Hoffmann, L.; Blank, J.; Woiwode, W.; Oelhaf, H.; Hösen, E.; Volk, C. M.; Ulanovsky, A.; Ravegnani, F.; Weigel, K.; Stroh, F.; Riese, M.

2012-05-01

257

Vertical wavenumber spectra of wind and temperature from high-resolution balloon soundings over Illinois  

NASA Astrophysics Data System (ADS)

We spectrally analyzed high-resolution balloon measurements of vertical profiles of temperature and horizontal wind in the troposphere and lower stratosphere over very flat terrain in Illinois. This paper is principally concerned with spectra in the power law range at vertical wavenumbers m ?10-3 cycle/m. The logarithmic spectral slopes and amplitudes are found to have only insignificant dependencies on meteorological parameters, including time of day, season, wind speed and direction, vertical shear, etc., except that between the troposphere and stratosphere the spectral amplitude scales as (N2)q with q ˜0.3, where N is the buoyancy frequency. The mean slopes are ?-3 in the stratosphere and ? -2.6 in the troposphere. On the average the individual spectra with larger amplitudes have less negative spectral slopes. The wide variation of spectral slopes (??0.5) and amplitudes and the weak dependence on N2 are quite inconsistent with the predictions of theories of saturated spectra. Further, the wind spectra in the troposphere and stratosphere are correlated, which suggests some unsaturated propagation between the regions. The ratio of kinetic to potential energy spectra is constant versus m, consistent with the linear gravity wave polarization relations. The magnitude of the model ratio can be brought into agreement with the observed ratio by assuming a model intrinsic frequency spectrum varying as ?-p with p ˜5/3 to 2 plus an enhancement of energy near the inertial frequency.

Nastrom, G. D.; van Zandt, T. E.; Warnock, J. M.

1997-03-01

258

Low aspect ratio wing experiment  

NASA Technical Reports Server (NTRS)

This test was initiated to provide validation data on low aspect ratio wings at transonic speeds. The test was conducted so that the data obtained would be useful in the validation of codes, and all boundary condition data required would be measured as part of the test. During the conduct of the test, the measured quantities were checked for repeatability, and when the data would not repeat, the cause was tracked down and either eliminated or included in the measurement uncertainty. The accuracy of the data was in the end limited by wall imperfections of the wind tunnel in which the test was run.

Olsen, Mike; Seegmiller, H. Lee

1994-01-01

259

Investigation on effectiveness of a prefabricated vertical drain during cyclic loading  

NASA Astrophysics Data System (ADS)

The effectiveness of prefabricated vertical drains (PVDs) in enhancing the stability of soft soils during cyclic loading was investigated using triaxial cyclic loading tests. Both undrained and with PVD tests were employed to study the associated excess pore pressure and accumulated strain under the repeated loading condition. The loading frequency and cyclic stress ratio have been chosen to be the variables which influence the performance of soft clays. The experimental results illustrate that with PVDs, the excess pore water pressure generation during cyclic loading decreases significantly. It is found that the excess pore water pressure build up depends on both loading frequency and cyclic stress ratio. The excess pore water pressure will increase when each of them is increased. Furthermore, when the loading frequency is 0.1 Hz, the ratio of coefficient of consolidation under cyclic loading to that under static loading is almost one. With the increasing loading frequency, this ratio increases accordingly.

Indraratna, B.; Ni, J.; Rujikiatkamjorn, C.

2010-06-01

260

Lunar vertical-shaft mining system  

NASA Technical Reports Server (NTRS)

This report proposes a method that will allow lunar vertical-shaft mining. Lunar mining allows the exploitation of mineral resources imbedded within the surface. The proposed lunar vertical-shaft mining system is comprised of five subsystems: structure, materials handling, drilling, mining, and planning. The structure provides support for the exploration and mining equipment in the lunar environment. The materials handling subsystem moves mined material outside the structure and mining and drilling equipment inside the structure. The drilling process bores into the surface for the purpose of collecting soil samples, inserting transducer probes, or locating ore deposits. Once the ore deposits are discovered and pinpointed, mining operations bring the ore to the surface. The final subsystem is planning, which involves the construction of the mining structure.

Introne, Steven D. (editor); Krause, Roy; Williams, Erik; Baskette, Keith; Martich, Frederick; Weaver, Brad; Meve, Jeff; Alexander, Kyle; Dailey, Ron; White, Matt

1994-01-01

261

Ozone vertical profile changes over South Pole  

NASA Technical Reports Server (NTRS)

Important changes in the ozone vertical profile over South Pole, Antarctica have occurred both during the recent period of measurements, 1986-1991, and since an earlier set of soundings was carried out from 1967-1971. From the onset of the 'ozone hole' over Antarctica in the early 1980s, there has been a tendency for years with lower spring ozone amounts to alternate with years with somewhat higher (although still depleted) ozone amounts. Beginning in 1989 there have been three consecutive years of strong depletion although the timing of the breakdown of the vortex has varied from year to year. Comparison of the vertical profiles between the two periods of study reveals the dramatic decreases in the ozone amounts in the stratosphere between 15-21 km during the spring. In addition, it appears that summer values are also now much lower in this altitude region.

Oltmans, S. J.; Hofmann, D. J.; Komhyr, W. D.; Lathrop, J. A.

1994-01-01

262

Vertical Landing Aerodynamics of Reusable Rocket Vehicle  

NASA Astrophysics Data System (ADS)

The aerodynamic characteristics of a vertical landing rocket are affected by its engine plume in the landing phase. The influences of interaction of the engine plume with the freestream around the vehicle on the aerodynamic characteristics are studied experimentally aiming to realize safe landing of the vertical landing rocket. The aerodynamic forces and surface pressure distributions are measured using a scaled model of a reusable rocket vehicle in low-speed wind tunnels. The flow field around the vehicle model is visualized using the particle image velocimetry (PIV) method. Results show that the aerodynamic characteristics, such as the drag force and pitching moment, are strongly affected by the change in the base pressure distributions and reattachment of a separation flow around the vehicle.

Nonaka, Satoshi; Nishida, Hiroyuki; Kato, Hiroyuki; Ogawa, Hiroyuki; Inatani, Yoshifumi

263

Experimental Studies in Helicopter Vertical Climb Performance  

NASA Technical Reports Server (NTRS)

Data and analysis from an experimental program to measure vertical climb performance on an eight-foot model rotor are presented. The rotor testing was performed using a unique moving-model facility capable of accurately simulating the flow conditions during axial flight, and was conducted from July 9, 1992 to July 16, 1992 at the Dynamic Model Track, or 'Long Track,' just prior to its demolition in August of 1992. Data collected during this brief test program included force and moment time histories from a sting-mounted strain gauge balance, support carriage velocity, and rotor rpm pulses. In addition, limited video footage (of marginal use) was recorded from smoke flow studies for both simulated vertical climb and descent trajectories. Analytical comparisons with these data include a series of progressively more detailed calculations ranging from simple momentum theory, a prescribed wake method, and a free-wake prediction.

McKillip, Robert M., Jr.

1996-01-01

264

On natural convection in vertical porous enclosures due to opposing fluxes of heat and mass prescribed at the vertical walls  

NASA Astrophysics Data System (ADS)

A two-dimensional mathematical model based on Darcy's law with Boussinesq approximation has been used to study double-diffusive natural convection in a rectangular fluid-saturated vertical porous enclosure subject to opposing and horizontal gradients of heat and solute. Results are presented for 50 less than or equal to R(sub c) less than or equal to 250, 0.01 less than or equal to N less than or equal to 10, 10 less than or equal to Le less than or equal to 40 and 1 less than or equal to A less than or equal to 10, where R(sub c), N, Le and A correspond to the solutal Rayleigh-Darcy number, inverse of buoyancy ratio, Lewis number and enclosure aspect ratio, respectively. The numerical integration of the full problem reveals that for sufficiently large R(sub c), Le and A, there is a domain of N in which one obtains oscillating convection. Outside this domain, the solution approaches steady-state convection, for which analytical solutions are developed and presented. The agreement between the analytical and the numerical solutions is shown to be satisfactory.

Alavyoon, Farid; Masuda, Yoshio; Kimura, Shigeo

1994-01-01

265

Vertical wind estimation from horizontal wind measurements  

NASA Technical Reports Server (NTRS)

This presentation begins with a brief description of the downdraft measurement problem for airborne Doppler based systems and the importance of the downdraft in assessing the hazard posed by a microburst wind shear. This is followed by a review of research on the feasibility of using simple microburst models to compute the downdraft from horizontal wind measurements. The current methodologies for computing the vertical wind are then discussed. A summary of the results and the plan for future research are also presented.

Vicroy, Dan D.

1992-01-01

266

Inverse scattering problem for quantum graph vertices  

SciTech Connect

We demonstrate how the inverse scattering problem of a quantum star graph can be solved by means of diagonalization of the Hermitian unitary matrix when the vertex coupling is of the scale-invariant (or Fueloep-Tsutsui) form. This enables the construction of quantum graphs with desired properties in a tailor-made fashion. The procedure is illustrated on the example of quantum vertices with equal transmission probabilities.

Cheon, Taksu; Turek, Ondrej [Laboratory of Physics, Kochi University of Technology, Tosa Yamada, Kochi 782-8502 (Japan); Exner, Pavel [Doppler Institute for Mathematical Physics and Applied Mathematics, Czech Technical University, Brehova 7, CZ-11519 Prague (Czech Republic); Nuclear Physics Institute ASCR, CZ-25068 Rez (Czech Republic)

2011-06-15

267

Vertical flight path steering system for aircraft  

NASA Technical Reports Server (NTRS)

Disclosed is a vertical flight path angle steering system for aircraft, utilizing a digital flight control computer which processes pilot control inputs and aircraft response parameters into suitable elevator commands and control information for display to the pilot on a cathode ray tube. The system yields desirable airplane control handling qualities and responses as well as improvements in pilot workload and safety during airplane operation in the terminal area and under windshear conditions.

Lambregts, Antonius A. (Inventor)

1983-01-01

268

Gas-solid flow in vertical tubes  

Microsoft Academic Search

This paper reports on a computational study of fully-developed flow of gas-particle suspensions in vertical pipes which was carried out, using the model proposed recently by Sinclair and Jackson, to understand the predicted scale-up characteristics. It was shown that the model can capture the existence of steady-state multiplicity wherein different pressure gradients can be obtained for the same gas and

Jorge A. Pita; Sankaran Sundaresan

1991-01-01

269

Mixed Convection in a Vertical Porous Channel  

Microsoft Academic Search

A numerical study of mixed convection in a vertical channel filled with a porous medium including the effect of inertial forces\\u000a is studied by taking into account the effect of viscous and Darcy dissipations. The flow is modeled using the Brinkman–Forchheimer-extended\\u000a Darcy equations. The two boundaries are considered as isothermal–isothermal, isoflux–isothermal and isothermal–isoflux for\\u000a the left and right walls of

J. C. Umavathi; J. P. Kumar; A. J. Chamkha; I. Pop

2005-01-01

270

Smooth Vertical Surface Climbing With Directional Adhesion  

Microsoft Academic Search

Stickybot is a bio-inspired robot that climbs smooth vertical surfaces such as glass, plastic and ceramic tile at 4 cm\\/s. The robot employs several design principles adapted from the gecko including a hierarchy of compliant structures, directional adhesion, and control of tangential contact forces to achieve control of adhesion. We describe the design and fabrication methods used to created under-actuated,

Sangbae Kim; Matthew Spenko; Salomon Trujillo; Barrett Heyneman; Daniel Santos; Mark R. Cutkosky

2008-01-01

271

Ozone vertical distribution in Mars polar atmosphere  

NASA Astrophysics Data System (ADS)

On the basis of an ultraviolet spectrum obtained over the north polar region of Mars by Mariner-9, the vertical profile of the ozone density is calculated. A density maximum is found at about 25 km height over the surface of the planet. Its value is about 1×1010molecules cm-3. The obtained result is compared to the results obtained by other authors.

Komitov, B.

272

Vertical-Cavity Surface-Emitting Lasers  

Microsoft Academic Search

The increasing interest in vertical-cavity surface- emitting lasers (VCSEL's) requires the corresponding develop- ment of circuit-level VCSEL models for use in the design and simulation of optoelectronic applications. Unfortunately, existing models lack either the computational efficiency or the com- prehensiveness warranted by circuit-level simulation. Thus, in this paper we present a comprehensive circuit-level model that accounts for the thermal and

P. V. Mena; J. J. Morikuni; S.-M. Kang; A. V. Harton; K. W. Wyatt

273

Engineering high-performance vertical cavity lasers  

SciTech Connect

The cw and high-speed performance of vertical cavity surface emitting laser diodes (VCSELs) are affected by both electrical and optical issues arising from the geometry and fabrication of these devices. Structures with low resistance semiconductor mirrors and Al-oxide confinement layers address these issues and have produced record performance including 50% power conversion efficiency and modulation bandwidths up to 20 GHz at small bias currents.

Lear, K.L.; Hou, H.Q.; Hietala, V.M.; Choquette, K.D.; Schneider, R.P. Jr.

1996-12-31

274

Measuring the vertical gradient of gravity  

NSDL National Science Digital Library

The free-air effect tells us that as elevation above sea level increases, gravitational acceleration g decreases at the rate of about 0.3086 mgal/meter. This effect is routinely corrected for when making gravity surveys. We will use the LaCoste & Romberg gravimeter to measure the free-air effect in a tall building on campus, and compare with the theoretical value. keywords: gravity; vertical gradient; gravimeter

Sternberg, Rob

275

High-Voltage Diamond Vertical Schottky rectifiers  

Microsoft Academic Search

We have designed, simulated and experimentally demonstrated high-voltage vertical diamond Schottky rectifiers. The rectifiers were fabricated on free-standing homo-epi films with remarkably low p-type doping using a lift-off process. Theoretical calculations have been performed to determine the thickness and doping concentration of the drift region. Devices with 20mum epi layer have been shown to block 3.7kV and conduct 0.6 A\\/cm2

W. Huang; T. P. Chow; J. Yang; J. E. Butler

2005-01-01

276

Stability of mixed convection in an anisotropic vertical porous channel  

NASA Astrophysics Data System (ADS)

This paper addresses the stability of mixed convective buoyancy assisted flow due to external pressure gradient and buoyancy force in a vertical fluid saturated porous channel with linearly varying wall temperature. The porous medium is assumed to be both hydrodynamically and thermally anisotropic. Two different types of temperature perturbations, (i) zero temperature and (ii) zero heat flux, have been considered to study the effect of anisotropic permeability and thermal diffusivity on the flow stability. The stability analysis indicated that the least stable mode is two-dimensional. Furthermore, the results show that for the same Reynolds number, the fully developed base flow is highly unstable (stable) for high (low) permeable porous media as well as for a porous medium with small (large) thermal diffusivity ratio. Depending on the magnitude of all parameters studied, three types of instabilities (shear, thermal, and mixed instability) occurred. The transition of instability from one type to another took place smoothly, except when the permeability ratio exceeded 6. Based on the value of the permeability ratio, the flow in an anisotropic medium for a specific Reynolds number may be either more or less stable than the flow in an isotropic medium. In addition, the fully developed flow is more stable for relatively small values of the modified Darcy number than for larger values. The effect of Brinkman as well as Forchheimer terms are negligible for the set of other parameters studied here. In contrast to a pure viscous fluid or an isotropic porous medium, which are characterized by unicellular convective cells, in anisotropic porous media convective cells may be unicellular or bicellular. The stability analysis of mixed convection in channels filled either with a viscous fluid or with an isotropic saturated porous medium may be obtained as special cases of the general study presented here.

Bera, P.; Khalili, A.

2002-05-01

277

Probing Uranus' Vertical Aerosol Structure at Equinox  

NASA Astrophysics Data System (ADS)

After a decade of quiescence following the Voyager flybys, Uranus' atmosphere has been exhibiting increasing activity approaching equinox that suggests a short timescale, dynamical, response in addition to a long timescale, radiative, response to the seasonal change of hemispheric heating. We propose to investigate this dichotomy by measuring Uranus' vertical aerosol structure over the entire surface, including both poles, at equinox when the forcing insolation is hemispherically symmetric, requiring that the sub-Earth latitude be less than a degree. Only at equinox {every 42 years} can the entire surface of the planet be viewed {over a full rotation} and mapped with the same viewing geometry. We will probe the morphology of the vertical haze structure using NICMOS narrow band filters beyond 1 micron to isolate different altitude regimes between the stratosphere and cloud deck and investigate its change since Cycle 7. We will use two complementary approaches: First, imaging will be done using medium- and narrow-band filters first to locate the dynamically-produced discrete cloud features, then to probe their vertical structure and morphology. The methane absorption bands are stronger in the proposed near-IR {1 to 2.5 microns} than at shorter wavelengths, and the strong H2 pressure-induced absorption from 2.1-2.4 microns contributes to the peak opacity. This enhances the visibility of transient, spatially isolated features and allows their structure to be probed to higher altitudes; namely, to the upper troposphere where they would be evidence of convective overshoot, a dynamical manifestation that would support strong seasonally-induced static instability. In addition to probing the structure with filter photometry, we will measure longitudinal limb profiles to probe the vertical background haze distribution vs latitude. HST/NICMOS is required because it avoids telluric water absorption and OH+O2 emission, and has a stable, well-characterized PSF, essential for limb studies and extracting the vertical structure of fine features crossing the disk. The proposed observations would complement the ground-based Uranus equinox campaign.

Trafton, Laurence

2007-07-01

278

Solving vertical and horizontal well hydraulics problems analytically in Cartesian coordinates with vertical and horizontal anisotropies  

NASA Astrophysics Data System (ADS)

SummaryA new generalized three-dimensional analytical solution is developed for a partially-penetrating vertical rectangular parallelepiped well screen in a confined aquifer by solving the three-dimensional transient ground water flow differential equation in x- y- z Cartesian coordinates system for drawdown by taking into account the three principal hydraulic conductivities ( Kx, Ky, and Kz) along the x- y- z coordinate directions. The fully penetrating screen case becomes equivalent to the single vertical fracture case of Gringarten and Ramey (1973). It is shown that the new solution and Gringarten and Ramey solution (1973) match very well. Similarly, it is shown that this new solution for a horizontally tiny fully penetrating parallelepiped rectangular parallelepiped screen case match very well with Theis (1935) solution. Moreover, it is also shown that the horizontally tiny partially-penetrating parallelepiped rectangular well screen case of this new solution match very well with Hantush (1964) solution. This new analytical solution can also cover a partially-penetrating horizontal well by representing its screen interval with vertically tiny rectangular parallelepiped. Also the solution takes into account both the vertical anisotropy ( azx = Kz/ Kx) as well as the horizontal anisotropy ( ayx = Ky/ Kx) and has potential application areas to analyze pumping test drawdown data from partially-penetrating vertical and horizontal wells by representing them as tiny rectangular parallelepiped as well as line sources. The solution has also potential application areas for a partially-penetrating parallelepiped rectangular vertical fracture. With this new solution, the horizontal anisotropy ( ayx = Ky/ Kx) in addition to the vertical anisotropy ( azx = Kz/ Kx) can also be determined using observed drawdown data. Most importantly, with this solution, to the knowledge of the author, it has been shown the first time in the literature that some well-known well hydraulics problems can also be solved in Cartesian coordinates with some additional advantages other than the conventional cylindrical coordinates method.

Batu, Vedat

2012-01-01

279

Magnetic coupling at vertical perovskite-spinel epitaxial interface  

NASA Astrophysics Data System (ADS)

Interfaces in complex oxides have been the focus of scientists because of their intriguing and unique properties that cannot be found in bulk. Vertical nanostructure is one of the most interesting heterostructure that has been studied for interface phenomena due to its high interface-volume ratio. In this study, (La,Ca)MnO3 (LCMO) (perovskite, matrix) / CoFe2O4 (CFO) (spinel, pillars, 50-200 nm in size) vertical nanostructure has been taken as model system to investigate the interface magnetic coupling with X-ray absorption spectroscopy and photoemission electron microscopy (PEEM), taking the advantages of their element sensitivity and spatial resolution. Matrix and pillars were studied separated with the photon energy set to different absorption edges. The magnetic order and valence states as well as site occupancy in CFO pillars were characterized by XMCD measurements at Co and Fe L-edges with the application of external magnetic fields. In order to investigate the exchange coupling at the interface, we combined this XMCD study with angular dependent XMLD measurements at Fe and Mn L-edges, which give us the information of orbital order in LCMO, while CFO pillars are magnetized in different directions. Similarly, XMCD studies at the Mn L-edges provide detailed insights into the magnetic order of the LCMO matrix, the Mn valence state and elucidate the impact of the CFO pillars. In addition, PEEM measurement provides spatially resolved XMCD/XMLD images that give more insight of the magnetic coupling at the matrix-pillar interface.

He, Qing; Arenholz, Elke; Yang, Jan-Chi; Chu, Ying-Hao

2012-02-01

280

Variable ratio regenerative braking device  

DOEpatents

Disclosed is a regenerative braking device (10) for an automotive vehicle. The device includes an energy storage assembly (12) having a plurality of rubber rollers (26, 28) mounted for rotation between an input shaft (36) and an output shaft (42), clutches (38, 46) and brakes (40, 48) associated with each shaft, and a continuously variable transmission (22) connectable to a vehicle drivetrain and to the input and output shafts by the respective clutches. The rubber rollers are torsionally stressed to accumulate energy from the vehicle when the input shaft is clutched to the transmission while the brake on the output shaft is applied, and are torsionally relaxed to deliver energy to the vehicle when the output shaft is clutched to the transmission while the brake on the input shaft is applied. The transmission ratio is varied to control the rate of energy accumulation and delivery for a given rotational speed of the vehicle drivetrain.

Hoppie, Lyle O. (Birmingham, MI)

1981-12-15

281

Characterizing Vertical Mass Flux Profiles in Aeolian Saltation Systems  

E-print Network

This dissertation investigates characteristics of the vertical distributions of mass flux observed in field and laboratory experiments. Thirty vertical mass flux profiles were measured during a field experiment in Jericoacoara, Brazil from October...

Farrell, Eugene

2012-07-16

282

Marine vertical cable multiple attenuation beyond up/down separation  

E-print Network

Marine vertical cable acquisition is an emerging technology. It represents an alternative to surface seismic acquisition in areas congested by platforms or other obstacles. The vertical cable acquisition consists of recording pressure at several...

Tran, Andre

2012-06-07

283

6. DETAIL OF VERTICAL LIFT SPAN AND FIXED SPAN IMMEDIATELY ...  

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

6. DETAIL OF VERTICAL LIFT SPAN AND FIXED SPAN IMMEDIATELY NORTH OF VERTICAL LIFT SPAN, LOOKING SOUTHEAST. - Shippingsport Bridge, Spanning Illinois River at State Route 51, La Salle, La Salle County, IL

284

Vertical axis wind turbine with continuous blade angle adjustment  

E-print Network

The author presents a concept for a vertical axis wind turbine that utilizes each blade's entire rotational cycle for power generation. Each blade has its own vertical axis of rotation and is constrained to rotate at the ...

Weiss, Samuel Bruce

2010-01-01

285

MODELLING THE ONSET OF DYNAMIC Importance of the Vertical Dimension  

E-print Network

MODELLING THE ONSET OF DYNAMIC FRICTION Importance of the Vertical Dimension by JÃ?RGEN TRÃ?MBORG and the direction out of the sliding plane, the vertical. By comparison to the one-dimensional model, I show

Johansen, Tom Henning

286

Weather-Corrected Performance Ratio  

SciTech Connect

Photovoltaic (PV) system performance depends on both the quality of the system and the weather. One simple way to communicate the system performance is to use the performance ratio (PR): the ratio of the electricity generated to the electricity that would have been generated if the plant consistently converted sunlight to electricity at the level expected from the DC nameplate rating. The annual system yield for flat-plate PV systems is estimated by the product of the annual insolation in the plane of the array, the nameplate rating of the system, and the PR, which provides an attractive way to estimate expected annual system yield. Unfortunately, the PR is, again, a function of both the PV system efficiency and the weather. If the PR is measured during the winter or during the summer, substantially different values may be obtained, making this metric insufficient to use as the basis for a performance guarantee when precise confidence intervals are required. This technical report defines a way to modify the PR calculation to neutralize biases that may be introduced by variations in the weather, while still reporting a PR that reflects the annual PR at that site given the project design and the project weather file. This resulting weather-corrected PR gives more consistent results throughout the year, enabling its use as a metric for performance guarantees while still retaining the familiarity this metric brings to the industry and the value of its use in predicting actual annual system yield. A testing protocol is also presented to illustrate the use of this new metric with the intent of providing a reference starting point for contractual content.

Dierauf, T.; Growitz, A.; Kurtz, S.; Cruz, J. L. B.; Riley, E.; Hansen, C.

2013-04-01

287

Ground-water sampling and time-series evaluation techniques to determine vertical concentration distributions  

SciTech Connect

Data analysis methodologies are developed for using time-series measurements of effluent concentrations during continuous sampling to determine the vertical shape and location of a horizontally uniform contaminant plume and to estimate physical/chemical aquifer parameters such as vertical anisotropy, effective porosity, and retardation factor. Temporal water-quality variations during constant-flow sampling are calculated in the form of concentration type curves for a wide variety of plume shapes and positions and are shown to be directly related to the geometry and growth rate of the three-dimensional capture volume of the well. An analytical type-curve solution is derived for discrete-interval sampling in homogeneous and isotropic/anisotropic aquifers containing plumes with complex vertical shapes that are described by the superposition of multiple Gaussian distributions. Results from two-dimensional, axisymmetric simulations of ground-water flow and particle transport demonstrate the sensitivity of concentration type curves to sandpack hydraulic conductivity, screen length, well diameter, flow through the well screen during discrete-interval sampling, aquifer anisotropy and heterogeneities, pumping rate, effective porosity, and chemical retardation. Two applications of the concentration type-curve method for determining plume and aquifer characteristics are presented. The first illustrates the use of discrete-interval sampling to evaluate the vertical shape and location of a hypothetical plume in a homogeneous, isotropic aquifer. In the second, extraction-well effluent data collected during a field experiment were used to evaluate the vertical concentration distribution in a sulfate plume and estimate the vertical anisotropy ratio of the aquifer. The results demonstrate the importance of developing consistency in purge and sample volumes to minimize artificial measurement variability in monitoring programs.

Cosler, D.J. [QST Environmental, Inc., Nashua, NH (United States)

1997-09-01

288

Vertical Transmission of Hepatitis C Virus: Systematic Review and Meta-analysis  

PubMed Central

Background.?We conducted a systematic review of estimates of hepatitis C virus (HCV) vertical transmission risk to update current estimates published more than a decade ago. Methods.?PubMed and Embase were searched and 109 articles were included. Pooled estimates of risk were generated for children born to HCV antibody–positive and viremic women, aged ?18 months, separately by maternal human immunodeficiency virus (HIV) coinfection. Results.?Meta-analysis of the risk of vertical HCV infection to children of HCV antibody–positive and RNA-positive women was 5.8% (95% confidence interval [CI], 4.2%–7.8%) for children of HIV-negative women and 10.8% (95% CI, 7.6%–15.2%) for children of HIV-positive women. The adjusted meta-regression model explained 51% of the between-study variation in the 25 included risk estimates. Maternal HIV coinfection was the most important determinant of vertical transmission risk (adjusted odds ratio, 2.56 [95% CI, 1.50–4.43]). Additional methodological (follow-up rate and definition of infection in children) and risk factors independently predicted HCV infection and need to be captured and reported by future studies of vertical transmission. Studies assessing the contribution of nonvertical exposures in early childhood to HCV prevalence among children at risk of vertical transmission are needed. Conclusions.?More than 1 in every 20 children delivered by HCV chronically infected women are infected, highlighting that vertical transmission likely constitutes the primary transmission route among children. These updated estimates are a basis for decision making in prioritization of research into risk-reducing measures, and inform case management in clinical settings, especially for HIV-positive women in reproductive age. PMID:24928290

Benova, Lenka; Mohamoud, Yousra A.; Calvert, Clara; Abu-Raddad, Laith J.

2014-01-01

289

Ozone variability in the atmospheric boundary layer in Maryland and its implications for vertical transport model  

NASA Astrophysics Data System (ADS)

Although much research has focused on daytime ozone (O 3) distribution in the atmospheric boundary layer, there remain many unresolved processes related to O 3 transport in the residual layer. To address such unresolved questions, a field study was conducted in Beltsville, MD during the summer of 2010 to study the spatial and temporal distribution of O 3 and other pollutants using ground-based gas analyzers and ozonesondes. During elevated pollution events in the daytime, the convective boundary layer, which reached a maximum depth of about 2 km, had nearly uniform O 3 levels of almost 100 parts per billion (ppbv). Due to intermittent and intense vertical turbulent motion, the residual layer became "leaky" and permitted vertical transport to enhance ground-level O 3 mixing ratios by as much as 10-30 ppbv in a span of 0.5-3 h. Model simulations, using the Weather Research and Forecasting model with Chemistry (WRF/Chem), were carried out to investigate the impact of different treatments of vertical mixing on the simulation of O 3 in the nocturnal boundary layer and residual layer. WRF/Chem model simulations provided realistic O 3 vertical distribution during the daytime. During the nighttime, in the residual layer, model outputs resulted in higher O 3 levels compared with the in-situ observations. Model sensitivity analyses showed that increasing the turbulent length scales and improved stability functions yielded improvements in the vertical transport of O 3 within the residual layer. One key conclusion of this study is that models such as WRF/Chem require improved numerical algorithms to properly account for the nocturnal vertical transport of O 3 in the residual region of the atmospheric boundary layer.

Hu, Xiao-Ming; Doughty, David C.; Sanchez, Kevin J.; Joseph, Everette; Fuentes, Jose D.

2012-01-01

290

Diel Vertical Migration Thresholds of Karenia brevis (Dinophyceae).  

EPA Science Inventory

Light and nutrient availability change throughout dinoflagellate diel vertical migration (DVM) and/or with subpopulation location in the water column along the west Florida shelf. Typically, the vertical depth of the shelf is greater than the distance a subpopulation can vertical...

291

Vertical integration, exclusive dealing, and ex post cartelization  

Microsoft Academic Search

This paper uncovers an unnoticed connection between exclusive contracts and vertical organization. A vertically integrated …rm can use exclusive dealing to foreclose an equally e¢ cient upstream competitor and to cartelize the downstream industry. Neither vertical integration nor exclusive dealing alone achieves these anticompetitive eects. The cartelization eect of these two practices may be limited when downstream …rms are het-

Yongmin Chen; Michael H. Riordan

2006-01-01

292

Regularization and finiteness of the Lorentzian loop quantum gravity vertices  

SciTech Connect

We give an explicit form for the Lorentzian vertices recently introduced for possibly defining the dynamics of loop quantum gravity. As a result of doing so, a natural regularization of the vertices is suggested. The regularized vertices are then proven to be finite. An interpretation of the regularization in terms of a gauge fixing is also given.

Engle, Jonathan [MPI fuer Gravitationsphysik (Albert-Einstein-Institut), Am Muehlenberg 1, D-14476 Potsdam (Germany); CPT, CNRS Case 907, Universite de la Mediterranee, F-13288 Marseille (France); Pereira, Roberto [CPT, CNRS Case 907, Universite de la Mediterranee, F-13288 Marseille (France)

2009-04-15

293

The vertical distribution of Radiolaria in the waters surrounding Japan  

Microsoft Academic Search

Geographic and vertical distribution patterns of living Radiolaria are closely related to the characters of the water column. We studied living Radiolaria in samples collected at closely spaced depth intervals in the waters surrounding Japan in order to understand their vertical distribution and its controlling factors. Such information is needed to reconstruct past vertical water mass structure. The Japanese Islands

Yoshiyuki Ishitani; Kozo Takahashi

2007-01-01

294

Full vertical car observer design methodology for suspension control applications  

E-print Network

Full vertical car observer design methodology for suspension control applications L. Dugarda , O of an H-observer to estimate the state variables of the vertical car dynamics to be used for suspension- sidered model is a 7 DOF full-car vertical model subject to unknown ground disturbances whose effects

Paris-Sud XI, Université de

295

The nature and growth of vertical specialization in world trade  

Microsoft Academic Search

Dramatic changes are occurring in the nature of international trade. Production processes increasingly involve a sequential, vertical trading chain stretching across many countries, with each country specializing in particular stages of a good's production sequence. We document a key aspect of these vertical linkages--the use of imported inputs in producing goods that are exported -- which we call vertical specialization.

David L. Hummels; Jun Ishii; Kei-Mu Yi

1999-01-01

296

Building FAÇADE Separation in Vertical Aerial Images  

NASA Astrophysics Data System (ADS)

Three-dimensional models of urban environments have great appeal and offer promises of interesting applications. While initially it was of interest to just have such 3D data, it increasingly becomes evident that one really would like to have interpreted urban objects. To be able to interpret buildings we have to split a visible whole building block into its different single buildings. Usually this is done using cadastral information to divide the single land parcels. The problem in this case is that sometimes the building boundaries derived from the cadastre are insufficiently accurate due to several reasons like old databases with lower accuracies or inaccuracies due to transformation between two coordinate systems. For this reason it can happen that a cadastral boundary coming from an old map is displaced by up to several meters and therefore divides two buildings incorrectly. To overcome such problems we incorporate the information from vertical aerial images. We introduce a façade separation method that is able to find individual building façades using multi view stereo. The purpose is to identify the individual façades and separate them from one another before on proceeds with the analysis of a façade's details. The source was a set of overlapping, thus "redundant" vertical aerial images taken by an UltraCam digital aerial camera. Therefore in a first step we determine the building block outlines using the building classification and use the height values from the Digital Surface Model (DSM) to determine approximate "façade quadrilaterals". We also incorporate height discontinuities using the height profiles along the building outlines to enhance our façade separation. In a next step we detect repeated pattern in these "façade images" and use them to separate the façades respectively building blocks from one another. We show that this method can be successfully used to separate building façades using vertical aerial images with a very high detection rate of 88%.

Meixner, P.; Wendel, A.; Bischof, H.; Leberl, F.

2012-07-01

297

Numerical modeling of vertical cavity semiconductor lasers  

SciTech Connect

A vertical cavity surface emitting laser (VCSEL) is a diode laser whose optical cavity is formed by growing or depositing DBR mirror stacks that sandwich an active gain region. The resulting short cavity supports lasing into a single longitudinal mode normal to the wafer, making these devices ideal for a multitude of applications, ranging from high-speed communication to high-power sources (from 2D arrays). This report describes the development of a numerical VCSEL model, whose goal is to both further their understanding of these complex devices and provide a tool for accurate design and data analysis.

Chow, W.W.; Hadley, G.R.

1996-08-01

298

Airglow response to vertically standing gravity waves  

NASA Technical Reports Server (NTRS)

There is currently much interest in fluctuations of airglow emissions caused by atmospheric gravity waves. The fluctuations of brightness tend to be found in phase (or occasionally in antiphase) with the fluctuations of measured temperature, whereas current theory tends to anticipate substantial phase differences. We suggest here that the discrepancy results from failure of the common theoretical assumption that the relevant gravity waves are dominated by a single upgoing component: that, instead, there is an accompanying downgoing component of comparable magnitude, produced by reflection. In the case of total reflection, simple, steady state chemistry and vertical viewing, the phase difference is necessarily zero (or 180 deg).

Hines, Colin O.; Tarasick, David W.

1994-01-01

299

Vertical cavity surface emitting terahertz laser.  

PubMed

Vertical cavity surface emitting terahertz lasers can be realized in conventional semiconductor microcavities with embedded quantum wells in the strong coupling regime. The cavity is to be pumped optically at half the frequency of the 2p exciton state. Once a threshold population of 2p excitons is achieved, a stimulated terahertz transition populates the lower exciton-polariton branch, and the cavity starts emitting laser light both in the optical and terahertz ranges. The lasing threshold is sensitive to the statistics of photons of the pumping light. PMID:23003086

Kavokin, A V; Shelykh, I A; Taylor, T; Glazov, M M

2012-05-11

300

Vertical Cable Seismic Survey for Hydrothermal Deposit  

NASA Astrophysics Data System (ADS)

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. We have carried out two field surveys in FY2011. 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, the VCS will become a practical exploration tool for the exploration of seafloor hydrothermal deposits.

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

2012-04-01

301

Wave formation on vertical falling liquid films  

SciTech Connect

The method of integral relations is used to derive a nonlinear ''two-wave'' structure equation for long waves on the surface of vertical falling liquid films. This equation is valid in a wide range of Reynolds numbers and reduces to the known equations for high and low Re. Theoretical data for the fastest growing waves are compared with the experimental results on velocities, wave numbers and growth rates of the waves in the inception region. The validity of theoretical assumptions is also confirmed by the direct measurements of the instantaneous velocity profiles in a wave liquid film.

Alekseenko, S.V.; Nakoryakov, V.E.; Pokusaev, B.G.

1985-09-01

302

Variable expansion ratio reaction engine  

SciTech Connect

A variable expansion ratio reaction rocket engine for producing a mainstream of hot combustion gases is described comprising: a reaction chamber including a thrust nozzle portion formed by converging and diverging wall portions in which the diverging portion terminates in a gas discharge and through which the combustion gases pass; a nozzle throat section at the juncture of the convergent-divergent wall portions; rows of circumferentially and axially spaced injection ports formed within the wall portions and communicating therethrough and into the reaction chamber; fluid conduit means in communication with the injection ports; at least one high pressure pump in communication with the fluid conduit means; a fluid containing storage tank including a conduit in communication with the high pressure pump; and means for selectively controlling a flow of fluid out of the tank, through the pump and to the fluid conduit means and the injection ports for controlling a cross-sectional area of the mainstream combustion gases passing through the thrust nozzle.

Wagner, W.R.

1987-11-24

303

Growth of high aspect ratio ZnO nanorods by solution process: Effect of polyethyleneimine  

SciTech Connect

High aspect ratio ZnO nanorods were grown vertically on ZnO seed layer deposited silicon, glass and polyimide substrates by a solution process at low-temperature using zinc nitrate hexahydrate and hexamethylenetetramine. We studied the effect of polyethlyeneimine (PEI) on the growth of ZnO nanorods. It was found that PEI has a prominent effect on controlling the aspect ratio of ZnO nanorods in solution. The morphological and photoluminescence properties of the ZnO nanorods were also examined with varying the growth temperature (60-90 Degree-Sign C). - Graphical abstract: With addition of polyehyleneimine (PEI) high aspect-ratio ZnO nanorods were grown. It is believed that during ZnO nanorods growth, protonized form of linear PEI molecules inhibits the lateral growth by being adsorbed on non-polar lateral planes. Thus the vertical growth is favored. Highlights: Black-Right-Pointing-Pointer A controlled growth of high aspect ratio ZnO nanorods on different substrates. Black-Right-Pointing-Pointer A prominent effect of polyethlyeneimine (PEI) on controlling the aspect ratio of ZnO nanorods in solution. Black-Right-Pointing-Pointer Precursor concentration and growth temperature effect for various aspect ratio ZnO nanorods.

Choi, Han-Seok; Vaseem, Mohammad; Kim, Sang Gon; Im, Yeon-Ho [School of Semiconductor and Chemical Engineering, Dept. of BIN Fusion Technology, BK 21 Centre for Future Energy Materials and Devices, and Nanomaterials Processing Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Hahn, Yoon-Bong, E-mail: ybhahn@chonbuk.ac.kr [School of Semiconductor and Chemical Engineering, Dept. of BIN Fusion Technology, BK 21 Centre for Future Energy Materials and Devices, and Nanomaterials Processing Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2012-05-15

304

Relation of vertical flux of particles smaller than 10 ?m to total aeolian horizontal mass flux at Owens Lake  

NASA Astrophysics Data System (ADS)

The vertical flux of particles smaller than 10 ?m for a saline playa surface, the particle size composition of which was classified as loam-textured, was estimated for a highly wind-erodible site on the playa of Owens (dry) Lake in California. The ratio of this vertical flux to the horizontal flux of total airborne material through a surface perpendicular to the soil and to the wind, Fa/qtot, is 2.75×10-4 m-1. This is consistent with that ratio for sand-textured soils and suggests that the binding energy and size of saltating particles for the tested surface material at Owens Lake is of the same order as that for sandier soils. The horizontal mass flux of saltating grains, q, in the reported wind erosion event is 51.3% of the total horizontal mass flux qtot. Therefore the ratio of Fa/q is 5.4×10-4 m-1.

Gillette, Dale A.; Fryrear, D. W.; Gill, Thomas E.; Ley, Trevor; Cahill, Thomas A.; Gearhart, Elizabeth A.

1997-11-01

305

Vertical-beam emittance correction with independent component analysis method  

NASA Astrophysics Data System (ADS)

The vertical-beam emittance in an electron storage ring is mainly determined by two factors: the linear betatron coupling and the spurious vertical dispersion generated by magnet errors. We find that the contribution of spurious vertical dispersion is larger than that generated by the linear betatron coupling. Using the independent component analysis (ICA) method, we develop stop band corrections to reduce the vertical emittance. We demonstrate our method by making ICA and correction to a quadruple-bend achromatic low emittance lattice. Six families of skew quadrupoles can effectively minimize both the vertical dispersion and the linear betatron coupling.

Wang, F.; Lee, S. Y.

2008-05-01

306

Compartment in vertical flow reactor for ferruginous mine water  

NASA Astrophysics Data System (ADS)

Mine effluents contain varying concentrations of ferrous ion along with other metal ions. Fe(II) that quickly oxidizes to form precipitates in the presence of oxygen under net alkaline or neutral conditions. Thus, passive treatment methods are designed for the mine water to reside in an open containment area so as to allow simultaneous oxidation and precipitation of Fe(II), such as in a lagoon or an oxidation pond. A vertical flow reactor (VFR) was also suggested to remediate ferruginous mine drainage passing down through an accreting bed of ochre. However, VFR has a limited operation time until the system begins to overflow. It was also demonstrated that two-compartment VFR has a longer operation time than single compartment VFR of same size. In this study, a mathematical model was developed as a part of efforts to explore the operation of VFR, showing dynamic changes in head differences, ochre depth and Fe(II)/Fe(III) concentration in the effluent flow. The analysis shows that Fe(II) oxidation and ochre formation should be balanced with permeability of ochre bed to maximize VFR operation time and minimize residual Fe(II) in the effluent. The model demonstrates that two compartment VFR can have a longer operation time than a single-compartment VFR and that an optimum compartment ratio exists that maximize VFR operation time. Accelerated Fe(II) oxidation significantly affects the optimum ratio of compartment area and reduced residual Fe(II) in the effluent. VFR operation time can be significantly prolonged by increasing the rate of ochre formation not by accelerated Fe(II) oxidation. Taken together, ochre forms largely in the first compartment while overflowed mine water with reduced iron contents is efficiently filtered in the second compartment. These results provide us a better understanding of VFR operation and optimum design criteria for maximum operation time in a two-compartment VFR. Rapid ochre accretion in the first compartment maintains constant hydraulic head to maximize flow passing down through the ochre bed. Filtration rate in the second compartment is also facilitated by thin ochre bed because of low residual Fe(II) in the overflow. Thus, compartment ratio also significantly affects the operation span of two-compartment VFR. Accelerated Fe(II) oxidation significantly affects the optimum ratio of compartment area and reduced residual Fe(II) in the effluent. VFR operation time can be significantly prolonged by increasing the rate of ochre formation not by accelerated Fe(II) oxidation.

Hur, Won; Cheong, Young-Wook; Yim, Gil-Jae; Ji, Sang-Woo; Hong, Ji-Hye

2014-05-01

307

An evaluation of the temperature, water vapor, and vertical velocity structure of aircraft contrails  

NASA Astrophysics Data System (ADS)

Measurements made in contrails formed in the wake of a Lear 35 have been analyzed with respect to their temperature, water vapor, and vertical velocity structure. The National Center for Atmospheric Research (NCAR) Sabreliner traversed the Lear's wake at distances varying from 150 m to 5 km and penetrated the contrails 243 times over the course of seven flights. The width of the plume is documented as a function of the distance between the leading and chase aircraft and the temperature, humidity and vertical motion components inside the plume have been analyzed and compared with a three dimensional wake vortex model. The analysis shows that the width increases very little within the first 5 km, in agreement with the vortex model. The increases in temperature and water vapor in the contrail 500 m from the exhaust were ?0.6° and 8 ppmv, respectively. The vertical velocity change across the contrail was ?4 m s-1. The agreement between observations and model predictions is quite good in comparisons of temperature. The model predicts larger water vapor mixing ratios, but the differences can be explained within the expected measurement uncertainties and lack of particle condensation in the vortex model. The model predicts larger excursions in vertical velocity but the trends are in excellent agreement between model and observations.

Baumgardner, Darrel; Miake-Lye, R. C.; Anderson, M. R.; Brown, R. C.

1998-04-01

308

Importance of light, temperature, zooplankton and fish in predicting the nighttime vertical distribution of Mysis diluviana  

USGS Publications Warehouse

The opossum shrimp Mysis diluviana (formerly M. relicta) performs large amplitude diel vertical migrations in Lake Ontario and its nighttime distribution is influenced by temperature, light and the distribution of its predators and prey. At one location in southeastern Lake Ontario, we measured the vertical distribution of mysids, mysid predators (i.e. planktivorous fishes) and mysid prey (i.e. zooplankton), in addition to light and temperature, on 8 occasions from May to September, 2004 and 2005. We use these data to test 3 different predictive models of mysid habitat selection, based on: (1) laboratory-derived responses of mysids to different light and temperature gradients in the absence of predator or prey cues; (2) growth rate of mysids, as estimated with a mysid bioenergetics model, given known prey densities and temperatures at different depths in the water column; (3) ratio of growth rates (g) and mortality risk (??) associated with the distribution of predatory fishes. The model based on light and temperature preferences was a better predictor of mysid vertical distribution than the models based on growth rate and g:?? on all 8 occasions. Although mysid temperature and light preferences probably evolved as mechanisms to reduce predation while increasing foraging intake, the response to temperature and light alone predicts mysid vertical distribution across seasons in Lake Ontario. ?? Inter-Research 2009.

Boscarino, B. T.; Rusdtam, L. G.; Eillenberger, J. L.; O'Gorman, R.

2009-01-01

309

Modular low aspect ratio-high beta torsatron  

DOEpatents

A fusion reactor device in which the toroidal magnetic field and at least a portion of the poloidal magnetic field are provided by a single set of modular coils. The coils are arranged on the surface of a low aspect ratio toroid in planes having the cylindrical coordinate relationship .phi.=.phi..sub.i +kz where k is a constant equal to each coil's pitch and .phi..sub.i is the toroidal angle at which the i'th coil intersects the z=o plane. The device may be described as a modular, high beta torsation whose screw symmetry is pointed along the systems major (z) axis. The toroid defined by the modular coils preferably has a racetrack minor cross section. When vertical field coils and preferably a toroidal plasma current are provided for magnetic field surface closure within the toroid, a vacuum magnetic field of racetrack shaped minor cross section with improved stability and beta valves is obtained.

Sheffield, George V. (Hopewell, NJ); Furth, Harold P. (Princeton, NJ)

1984-02-07

310

Strain-induced vertical self-organization of semiconductor quantum dots: A computational study  

SciTech Connect

Atomistic strain simulations based on the valence force field method are employed to study the vertical arrangements of semiconductor quantum dot (QD) multilayers. The effects of the QD shape, dimensions, and materials parameters are systematically investigated, varying independently the following parameters: spacer width H, QD lateral spacing D, base b, and height h, slope of the side facets, elastic properties of the dot and the substrate materials, and lattice mismatch between the dot and the substrate. The transition between vertically aligned and anti-aligned structures is found to be determined mainly by the ratios H/D and b/D, as well as by the strain anisotropy of the substrate and to a lesser extent of the QD. The dependence on the QD height h is significant only for steep side facets and large aspect ratios h/b, and the effects of the lattice mismatch strain and the bulk elastic moduli are found to be negligible. The comparison with experimental data shows an excellent agreement with the results from the simulations, demonstrating that the presented analysis results in precise theoretical predictions for the vertical self-organization regime in a wide range of QD materials systems.

Shtinkov, N., E-mail: nshtinkov@uottawa.ca [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa (Ontario) K1N 6N5 (Canada)

2013-12-28

311

Potential versus actual contribution of vertical transmission to pathogen fitness  

PubMed Central

Theory predicts that virulent parasites cannot be maintained at high prevalence if they are only vertically transmitted. However, parasites with high rates of vertical transmission that cause severe reduction in host fitness have been reported. Atkinsonella hypoxylon is a fungal pathogen capable of both vertical and horizontal transmission that drastically reduces its host's fitness. In contrast with theoretical predictions, field and laboratory observations suggested that the primary mechanism of transmission was vertical. Using randomly amplified polymorphic DNA markers, we investigated the effective contribution of vertical and horizontal transmission to the genetic structure of three natural populations of A. hypoxylon. We found high genotypic diversity and low linkage disequilibrium, indicating that most established genotypes are derived from horizontally transmitted, sexual spores. The low contribution of vertical transmission to the parasite's fitness despite its high potential might be due to lower establishment of cleistogamous seeds (through which vertical transmission occurs) or lower vigour of vertically transmitted fungal genotypes. Low establishment of vertically infected hosts might explain the persistence of virulent parasites with high apparent vertical transmission. Our results suggest that caution must be taken when using the potential for vertical transmission to make predictions about the evolution of parasite virulence.

Kover, P. X.; Dolan, T. E.; Clay, K.

1997-01-01

312

Theoretical analysis of vertical colloidal deposition.  

PubMed

We have modeled the dynamics of a relatively new deposition technique, vertical colloidal deposition (VCD), for preparing nanoparticle thin films. In this process, the substrate is placed vertically in a nanoparticle suspension and is gradually exposed by evaporation or other slow solvent removal. During the film's formation, we observe that the colloidal particles are deposited only at the solid-liquid-gas interface. In contrast with the horizontal geometry, treated elsewhere, where the meniscus is pinned, we observe qualitatively different deposition behaviors. In particular, uniform films rather than rings or lines are produced. Thus, we are led to model a diffusion-driven rather than a convection-driven film growth kinetics, and we are able to predict, consistent with our experimental observations, that the film's areal density is inversely proportional to the descent speed of the suspension surface. Additionally, we find that for submonolayer films, the areal density is proportional to the square of the suspension concentration, converting to a linear dependence once monolayer coverage is attained. PMID:15918750

Diao, J J; Hutchison, J B; Luo, Guanghong; Reeves, M E

2005-05-01

313

Uniform head in horizontal and vertical wells.  

PubMed

The steady-state head within a fully penetrating well may be estimated by evaluating the Thiem equation at the radius of the well. A method is presented here to extend results from the Thiem equation to horizontal wells and to partially penetrating wells. The particular model used in this investigation is based upon the analytic element method; it accurately reproduces a boundary condition of uniform head along the cylindrical surface at the perforated face of the well. This model is exercised over a representative range of parameters including the well's length, radius, and pumping rate, and the aquifer's hydraulic conductivity and thickness. Results are presented in a set of figures and tables that compare the well's drawdown to the drawdown that would have been obtained using the Thiem solution with the same pumping rate and radius. A methodology is presented to estimate the head within a horizontal or partially penetrating well by adding a correction term to results that can be readily obtained from computer models of vertical fully penetrating wells. This approach may also be used to contrast the differences in head between horizontal and vertical wells of various lengths, radii, and placement elevations. PMID:16405471

Steward, David R; Jin, Wei

2006-01-01

314

Vertical Profiling of Air Pollution at RAPCD  

NASA Technical Reports Server (NTRS)

The interaction between local and regional pollution levels occurs at the interface of the Planetary Boundary Layer and the Free Troposphere. Measuring the vertical distribution of ozone, aerosols, and winds with high temporal and vertical resolution is essential to diagnose the nature of this interchange and ultimately for accurately forecasting ozone and aerosol pollution levels. The Regional Atmospheric Profiling Center for Discovery, RAPCD, was built and instrumented to address this critical issue. The ozone W DIAL lidar, Nd:YAG aerosol lidar, and 2.1 micron Doppler wind lidar, along with balloon- borne ECC ozonesondes form the core of the W C D instrumentation for addressing this problem. Instrumentation in the associated Mobile Integrated Profiling (MIPS) laboratory includes 91 5Mhz profiler, sodar, and ceilometer. The collocated Applied particle Optics and Radiometry (ApOR) laboratory hosts an FTIR along with MOUDI and optical particle counters. With MODELS-3 analysis by colleagues in the National Space Science and Technology Center on the UAH campus and the co- located National Weather Service Forecasting Office in Huntsville, AL we are developing a unique facility for advancing the state of the science of pollution forecasting.

Newchurch, Michael J.; Fuller, Kirk A.; Bowdle, David A.; Johnson, Steven; Knupp, Kevin; Gillani, Noor; Biazar, Arastoo; Mcnider, Richard T.; Burris, John

2004-01-01

315

Vertically integrated ZnO-Based 1D1R structure for resistive switching  

NASA Astrophysics Data System (ADS)

We report a ZnO-based 1D1R structure, which is formed by a vertical integration of a FeZnO/MgO switching resistor (1R) and an Ag/MgZnO Schottky diode (1D). The multifunctional ZnO and its compounds are grown through MOCVD with in situ doping. For the R element, the current ratio of the high-resistance state (HRS) over the low-resistance state (LRS) at 1 V is 2.4 × 106. The conduction mechanisms of the HRS and LRS are Poole-Frenkel emission and resistive conduction, respectively. The D element shows the forward/reverse current ratio at ±1 V to be 2.4 × 107. This 1D1R structure exhibits high RHRS/RLRS ratio, excellent rectifying characteristics and robust retention.

Zhang, Yang; Duan, Ziqing; Li, Rui; Ku, Chieh-Jen; Reyes, Pavel I.; Ashrafi, Almamun; Zhong, Jian; Lu, Yicheng

2013-04-01

316

Noise of the Harrier in vertical landing and takeoff  

NASA Technical Reports Server (NTRS)

The noise of the Harrier AV8C aircraft in vertical takeoff and landing was measured 100 feet to the side of the aircraft where jet noise dominates. The noise levels were quite high - up to 125 dB overall sound level at 100 feet. The increased noise due to jet impingement on the ground is presented as a function of jet height to diameter ratio. The impingement noise with the aircraft close to the ground was 14 to 17 dB greater than noise from a free jet. Results are compared with small-scale jet impingement data acquired elsewhere. The agreement between small-scale and full-scale noise increase in ground effect is fairly good except with the jet close to the ground. It is proposed that differences in the jet Reynolds numbers and the resultant character of the jets may be partially responsible for the disparity in the full-scale and small-scale jet impingement noise. The difference between single-jet impingement and multiple-jet impingement may also have been responsible for the small-scale and full-scale disagreement.

Soderman, Paul T.; Foster, John D.

1988-01-01

317

Steady flow past a vertical surface-piercing circular cylinder  

NASA Astrophysics Data System (ADS)

This paper describes experiments in which a vertical surface-piercing circular cylinder with a large draught was towed at steady speeds through water initially at rest. The cylinder diameter d was 210mm, and measurements were made of pressures around its circumference at elevations between 2.4d below still water level to 0.7d above, at Froude numbers (based on d) up to 1.67. The tests were carried out at a constant ratio of Reynolds number to Froude number of 2.79×105. The total resistance coefficient reached a maximum at a Froude number of about 1, when that part of the loading that can be attributed to the presence of the free surface was equivalent to the submerged form drag on a length of cylinder of about 0.9d. Measurements are also presented of the run-up on the front of the cylinder and of the depth of the depression at the back. Previous measurements by Hay (Flow about Semi-submerged Cylinders of Finite Length. Princeton University Report, Princeton, NJ, 1947) for the case of a cylinder with a submerged free end, and by Hsieh (Proc. Am. Soc. Civil Eng. 90 (1964) 161) of forces on cylinders standing on the floor of an open channel, are reanalysed. In most respects these results are found to be compatible with the present data for a cylinder of large draught.

Chaplin, J. R.; Teigen, P.

2003-09-01

318

Edge technique Doppler lidar wind measurements with high vertical resolution.  

PubMed

We have developed a Doppler lidar system using the edge technique and have made atmospheric lidar wind measurements. Line-of-sight wind profiles with a vertical resolution of 22 m have a standard deviation of 0.40 m /s for a ten-shot average. Day and night lidar measurements of the vector wind have been made for altitudes from 200 to 2000 m. We validated the lidar measurements by comparing them with independent rawinsonde and pilot balloon measurements of wind speed and direction. Good agreement was obtained. The instrumental noise for these data is 0.11 m /s for a 500-shot average, which is in good agreement with the observed minimum value of the standard deviation for the atmospheric measurements. The average standard deviation over 30 mins varied from 1.16 to 0.25 m /s for day and night, respectively. High spatial and temporal resolution lidar profiles of line-of-sight winds clearly show wind shear and turbulent features at the 1 -2-m /s level with a high signal-to-noise ratio and demonstrate the potential of the edge-technique lidar for studying turbulent processes and atmospheric dynamics. PMID:18259439

Korb, C L; Gentry, B M; Li, S X

1997-08-20

319

Density Ratio Examples Semiparametric Statistical Formulation  

E-print Network

UMinformal Density Ratio Examples Semiparametric Statistical Formulation Combined semiparametric density estimators Semiparametric regression Application to Testicular Germ Cell Cancer Semiparametric Density Ratio Examples Semiparametric Statistical Formulation Combined semiparametric density estimators

Johnson, Raymond L.

320

Carbon Nanotubes as a Framework for High-Aspect-Ratio MEMS Fabrication  

Microsoft Academic Search

A class of carbon-nanotube (CNT) composite materials was developed to take advantage of the precise high-aspect-ratio shape of patterned vertically grown nanotube forests. These patterned forests were rendered mechanically robust by chemical vapor infiltration and released by etching an underlying sacrificial layer. We fabricated a diverse variety of functional MEMS devices, including cantilevers, bistable mechanisms, and thermomechanical actuators, using this

David N. Hutchison; Nicholas B. Morrill; Quentin Aten; Brendan W. Turner; Brian D. Jensen; Larry L. Howell; Richard R. Vanfleet; Robert C. Davis

2010-01-01

321

Fabrication of vertical alignment in ferroelectric liquid crystals for display application  

NASA Astrophysics Data System (ADS)

In this study, we focus on vertical alignment ferroelectric liquid crystals (VA-FLCs), because an FLC display with a high contrast ratio is expected. In the VA, although the normal of smectic layers is vertical to the substrate surface, the director of FLC molecules must tilt to the substrate surface at the tilt angle of FLC molecules. Thus, it is usually difficult to obtain a uniform VA in FLCs. We determine the optimum conditions for the fabrication of VA-FLC cells in terms of the tilt angle of FLC molecules, the anchoring strength of the alignment film, and the cell gap. Results indicate that the FLC with a small tilt angle tends to form good VA, which can be obtained by utilizing alignment films with high surface anchoring strengths. Good VA strongly depends on the cell gap.

Furue, Hirokazu; Horiguchi, Toshiki; Yamamichi, Miyuki; Oka, Shinichiro; Komura, Shinichi; Kobayashi, Shunsuke

2014-09-01

322

Vertical and Interfacial Transport in Wetlands (Invited)  

NASA Astrophysics Data System (ADS)

The objective of this work is to understand the fluxes connecting the water column, substrate, and atmosphere in wetland environments. To do this, analytical, numerical, and laboratory models have been used to quantify the hydrodynamic contributions to vertical fluxes. A key question is whether the hydrodynamic transport can be modeled as a diffusivity, and, if so, what the vertical structure of this diffusivity is. This question will be addressed in a number of flow types and for a number of fluxes. The fluxes of interest are heat, sediment, dissolved gases (such as methane and oxygen) and other dissolved solutes (such as nutrients and pollutants). The flows of interest include: unidirectional current, reversing flow (under waves, seiches, and tides), wind-sheared surface flows, and thermal convection. Rain and bioturbation can be important, but are not considered in the modeling work discussed herein. Specifically, we will present results on gas transport at wind-sheared free surface, sediment transport in unidirectional flow, and heat transfer in an oscillating flow cause by a seiche. All three of these will be used to consider the question of appropriate analytical models for vertical transport. The analytic models considered here are all 1D models that assume homogeneity in the horizontal plane. The numerical models use finite element methods and resolve the flow around individual vegetation stems in an idealized geometry. Laboratory models discussed herein also use an idealized geometry. Vegetation is represented by an array of cylinders, whose geometry is modeled after Scirpus spp. wetlands in Northern California. The laboratory model is constructed in a way that allows optical access to the flow, even in dense vegetation and far from boundaries. This is accomplished by using fluoropolymer plastics to construct vegetation models. The optical access allows us to employ particle image velocimetry (PIV) and planar laser induced fluorescence (PLIF) to measure the velocity and scalar fields, respectively. To study sediment transport, an additional step is needed. Idealized sediment grains are manufactured, again using fluoropolymers. This allows the sediment and fluid phase to be resolved simultaneously, and the velocities of each to be determined independently of the other. The use of fluoropolymers means that the laboratory imaging techniques do not suffer from blockage during laser light delivery or during image capture by digital cameras. Cameras are paired and run in stereoscopic mode to allow three-dimensional velocities to be determined. This is important given the 3D nature of flow through vegetation. Current results from ongoing laboratory, field, and modeling efforts will be discussed, as well as the upcoming steps.

Variano, E. A.

2010-12-01

323

Learning About Ratios: A Sandwich Study  

NSDL National Science Digital Library

This lesson introduces students to the concept of ratio through a hands-on, delicious experiment. After an introductory activity where students identify the ratio of girls to boys in a group of 10 selected students, they create six different peanut butter and jelly sandwiches with different ingredient ratios to find which is the tastiest. Students then plan their own similar experiment using other concoctions which can be expressed in ratios.

Weinberg, Sheryl

1999-01-16

324

Vertical GPS ground motion rates in the Euro-Mediterranean region: new evidence of vertical velocity gradients at different spatial scales along the Nubia-Eurasia plate boundary  

NASA Astrophysics Data System (ADS)

We use 2.5 to 14 years long position time-series from ~1000 continuous GPS stations to study vertical ground motions in the Euro-Mediterranean region and provide a first synoptic view of the vertical velocity field along the broad Nubia-Eurasia plate boundary. By estimating and removing common mode errors in position time-series from the results of a principal component analysis, we obtain a significant gain in the signal-to-noise ratio of the displacements data. Following the results of a maximum likelihood estimation analysis, which gives a mean spectral index ~-0.7, we adopt a power-law + white noise stochastic model in estimating the final vertical rates, and find 95% of the velocities within ×2 mm/yr in the study area, with uncertainties from filtered time-series ~40% smaller than from the unfiltered ones. We evaluate the contribute of the glacial isostatic adjustment (GIA) signal to the vertical velocity budget using two different global models, characterized by distinct rheological layering of the Earth's mantle and different descriptions of the time-history of the mass of continental ice sheets since the Last Glacial Maximum. The analysis carried out allows us to highlight, for the first time, the presence of statistically significant, and spatially coherent, velocity gradients where a higher density of stations is available. We find undulations of the vertical velocity field occurring at different spatial scales both in regions characterized by tectonic activity, like eastern Alps, Apennines and eastern Mediterranean, and regions characterized by low to null tectonic activity, like central Iberia and western Alps. Correcting the observed velocities for GIA, although the two models used predict different GIA velocities and patterns, doesn't change significantly the velocity gradients. A correlation between smooth vertical velocities and topographic features is apparent in many sectors of the study area. GIA and weathering processes cannot completely explain the measured rates, and a combination of active tectonics and deep-seated geodynamic processes must be used to explain our observations. Excluding areas where more localized processes are likely, or where subduction/delamination processes may be active, mantle dynamics is the most likely process, but regional mantle modeling is required for a better understanding.

Serpelloni, E.; Faccenna, C.; Spada, G.; Dong, D.; Williams, S. D.

2013-12-01

325

12 CFR 567.8 - Leverage ratio.  

Code of Federal Regulations, 2010 CFR

...Requirements § 567.8 Leverage ratio. (a) The minimum leverage...chapter, shall consist of a ratio of core capital to adjusted...excellent asset quality, high liquidity, and good earnings. ...requirement shall consist of a ratio of core capital to...

2010-01-01

326

Trends in the Vertical Distribution of Ozone  

NASA Technical Reports Server (NTRS)

Recent reanalyses of satellite, ground-based and balloon measurements allow updated estimates of trends in the vertical profile of ozone during 1980-96. The results show overall consistency between several independent measurement systems, particularly for northern hemisphere mid-latitudes where most ground-based measurements are made. Combined trend estimates over these latitudes show statistically significant negative trends at all altitudes between 10 and 45 km, with two local maxima: -7.4 +/- 2.0%/decade at 40 km and -7.6 +/- 4.6%/decade at 15 km altitude. There is a strong seasonal variation in trends over northern mid-latitudes in the altitude range of 10- 18 km. The profile trends are in quantitative agreement with independently measured trends in column ozone.

Randel, William J.; Stolarski, Richard S.; Cunnold, Derek M.; Logan, Jennifer A.; Newchurch, M. J.

1998-01-01

327

Vertical root fracture: prevalence, etiology, and diagnosis.  

PubMed

A vertical root fracture (VRF) is a frustrating complication that may occur following root canal treatment, and in almost every case leads to the extraction of the affected tooth. This type of fracture is usually diagnosed by secondary symptoms that develop some time after primary treatment, often when prosthodontic restoration has already been completed. The fracture line itself is often not directly visible, and therefore clinical and radiographic signs and symptoms indicate the diagnosis indirectly. Knowledge of the condition and pathogenesis of VRF is required in order to avoid hopeless trials of periodontal and/or endodontic therapy. Several etiologic factors are discussed that make teeth susceptible to VRF, such as the loss of substance due to restorative and endodontic therapy and stress factors associated with root canal debridement, and filling. PMID:23757466

Haueisen, Helga; Gärtner, Kathrin; Kaiser, Lea; Trohorsch, Dominik; Heidemann, Detlef

2013-07-01

328

Hydroelastic wave diffraction by a vertical cylinder.  

PubMed

A linear three-dimensional problem of hydroelastic wave diffraction by a bottom-mounted circular cylinder is analysed. The fluid is of finite depth and is covered by an ice sheet, which is clamped to the cylinder surface. The ice stretches from the cylinder to infinity in all lateral directions. The hydroelastic behaviour of the ice sheet is described by linear elastic plate theory, and the fluid flow by a potential flow model. The two-dimensional incident wave is regular and has small amplitude. An analytical solution of the coupled problem of hydroelasticity is found by using a Weber transform. We determine the ice deflection and the vertical and horizontal forces acting on the cylinder and analyse the strain in the ice sheet caused by the incident wave. PMID:21690136

Brocklehurst, Paul; Korobkin, Alexander; P?r?u, Emilian I

2011-07-28

329

Vertical integration and optimal reimbursement policy  

PubMed Central

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. PMID:21850551

Afendulis, Christopher C.

2011-01-01

330

Vertical spin transport in semiconductor heterostructures  

NASA Astrophysics Data System (ADS)

The Landauer-Büttiker formalism combined with the tight-binding transfer matrix method is employed to model vertical coherent spin transport within magnetization-modulated semiconductor heterostructures based on GaAs. This formalism provides excellent physical description of recent experiments concerning the high tunneling magnetoresistance (TMR) in (Ga,Mn)As-based trilayers and highly polarized spin injection in p-(Ga ,Mn)As/n-GaAs Zener diodes. For both the TMR and the Zener spin current polarization, the calculated values compare well with those observed in the experiments, and the formalism reproduces the strong decrease of the observed effects with external bias. We ascribe this decrease to band structure effects. The role played in the spin-dependent tunneling by carrier concentration and magnetic ion content is also studied.

Sankowski, P.; Kacman, P.; Majewski, J. A.; Dietl, T.

2007-02-01

331

Development of Vertical Cable Seismic System (2)  

NASA Astrophysics Data System (ADS)

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 uncertainty in the locations of the source and of the hydrophones in water could lower the quality of subsurface image. It is, therefore, strongly necessary to develop a total survey system that assures an accurate positioning and a deployment techniques. In case of shooting on sea surface, GPS navigation system are available, 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 as requested for the SMS survey. We will incorporate the accurate LBL navigation systems with VCs. The LBL navigation system has been developed by IIS of the University of Tokyo. The error is estimated less than 10cm at the water depth of 3000m. Another approach is that the shot points can be calculated using the first break of the VCS after the VCS locations are estimated by slant-ranging from the sea surface. Our VCS system has been designed as a survey tool for hydrothermal deposit, but it will be also applicable for deep water site surveys or geohazard assessment such as active faults.

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

2012-12-01

332

Oceanography. Vertical mixing in the ocean.  

PubMed

The thermohaline circulation of the ocean results primarily from downwelling at sites in the Nordic and Labrador Seas and upwelling throughout the rest of the ocean. The latter is often described as being due to breaking internal waves. Here we reconcile the difference between theoretical and observed estimates of vertical mixing in the deep ocean by presenting a revised view of the thermohaline circulation, which allows for additional upwelling in the Southern Ocean and the separation of the North Atlantic Deep Water cell from the Antarctic Bottom Water cell. The changes also mean that much less wind and tidal energy needs to be dissipated in the deep ocean than was originally thought. PMID:11343103

Webb, D J; Suginohara, N

2001-01-01

333

Opportunity's Surroundings on Sol 1687 (Vertical)  

NASA Technical Reports Server (NTRS)

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008).

Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction.

Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast.

This view is presented as a vertical projection with geometric seam correction.

2009-01-01

334

Opportunity's Surroundings on Sol 1818 (Vertical)  

NASA Technical Reports Server (NTRS)

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends.

This view is presented as a vertical projection with geometric seam correction. North is at the top.

The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view.

The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

2009-01-01

335

Opportunity's Surroundings After Sol 1820 Drive (Vertical)  

NASA Technical Reports Server (NTRS)

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009).

This view is presented as a vertical projection with geometric seam correction. North is at the top.

The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.

2009-01-01

336

Opportunity's Surroundings on Sol 1798 (Vertical)  

NASA Technical Reports Server (NTRS)

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top.

This view is presented as a vertical projection with geometric seam correction.

The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

2009-01-01

337

Bidirectional operation of vertical organic triodes  

NASA Astrophysics Data System (ADS)

Due to their effective short channel length of only a few hundred nanometers, vertical organic triodes (VOTs) have a high potential to overcome problems of low current densities and switching speed in current organic field effect transistors (OFETs). Furthermore, VOTs are easy to build because no sub-structuring of the base contact is necessary. Nevertheless, these devices are poorly investigated. In literature, two different working mechanisms are suggested: hot carrier transport through the metallic base or transport of charge carriers through a permeable base electrode. As a strong asymmetry is expected for function principle based on hot carriers, we are able to distinguish between both mechanisms by examining the bidirectional transmission properties of the VOT consisting of electron transporting materials. We show that high transmission values (>95%) are possible for both directions, suggesting a base contact with openings forming a grid electrode.

Fischer, Axel; Siebeneicher, Philipp; Kleemann, Hans; Leo, Karl; Lüssem, Björn

2012-02-01

338

Integrality ratio for Group Steiner Trees and Directed Steiner Trees # Eran Halperin + Guy Kortsarz # Robert Krauthgamer Aravind Srinivasan  

E-print Network

Steiner Tree problem, as well as for its generalization, the Directed Steiner Tree problem, is a flow. For the Group Steiner Tree problem, we show the integrality ratio is#16 2 k), where k denotes the number is tight. This also applies for the Directed Steiner Tree problem. In terms of the number n of vertices

Krauthgamer, Robert

339

CALIPSO Observations of Transatlantic Dust: Vertical Stratification and Effect of Clouds  

NASA Technical Reports Server (NTRS)

CALIOP nighttime measurements of lidar backscatter, color and depolarization ratios during the summer of 2007 are used to study transatlantic dust properties downwind of Saharan sources, and to examine the interaction of clouds and dust. We discuss the following findings: (1) while lidar backscatter doesn't change much with altitude in the Saharan Air Layer (SAL), depolarization and color ratios both increase with altitude in the SAL; (2) lidar backscatter and color ratio increase as dust is transported westward in the SAL; (3) the vertical lapse rate of dust depolarization ratio increases within SAL as plumes move westward; (4) nearby clouds barely affect the backscatter and color ratio of dust volumes within SAL but not so below SAL. Finally, (5) the odds of CALIOP finding dust below SAL next to clouds are about 2/3 of those far away from clouds. This feature, together with an apparent increase in depolarization ratio near clouds, indicates that particles in some dusty volumes lose asphericity in the humid air near clouds, and cannot be identified by CALIPSO as dust.

Yang, Weidong; Marshak, Alexander; Varnai, Tamas; Kalashnikova, Olga V.; Kostinski, Alexander B.

2012-01-01

340

Constraints on aerosol processes in climate models from vertically-resolved aircraft observations of black carbon  

NASA Astrophysics Data System (ADS)

Evaluation of the aerosol schemes in current climate models is dependent upon the available observational data. In-situ observations from flight campaigns can provide valuable data about the vertical distribution of aerosol that is difficult to obtain from satellite or ground-based platforms, although they are localised in space and time. Using single-particle soot-photometer (SP2) measurements from the HIAPER Pole-to-Pole Observations (HIPPO) campaign, which consists of many vertical profiles over a large region of the Pacific, we evaluate the meridional and vertical distribution of black carbon (BC) aerosol simulated by the HadGEM3-UKCA and ECHAM5-HAM2 models. Both models show a similar pattern of overestimating the BC column burden compared to that derived from the observations, in many areas by an order of magnitude. However, by sampling the simulated BC mass mixing ratio along the flight track and comparing to the observations, we show that this discrepancy has a rather different vertical structure in the two models. Using this methodology, we conduct sensitivity tests on two specific elements of the models: biomass-burning emissions and scavenging by convective precipitation. We show that, by coupling the convective scavenging more tightly with convective transport, both the column burden and vertical distribution of BC in HadGEM3-UKCA are significantly improved with respect to the observations, demonstrating the importance of a realistic representation of this process. In contrast, updating from GFED2 to GFED3.1 biomass-burning emissions makes a more modest improvement in both models, which is not statistically significant. We also demonstrate the important role that nudged simulations (where the large-scale model dynamics are continuously relaxed towards a reanalysis) can play in this type of evaluation, allowing statistically significant differences between configurations of the aerosol scheme to be seen where the differences between the corresponding free-running simulations would not be significant.

Kipling, Z.; Stier, P.; Schwarz, J. P.; Perring, A. E.; Spackman, J. R.; Mann, G. W.; Johnson, C. E.; Telford, P. J.

2013-01-01

341

A prototype for an economical vertical microstomia orthosis.  

PubMed

One of the complications of thermal injury is the development of scars and contractures during the healing process. This scarring can be devastating, especially when it involves the mouth. The purpose of this report is to describe the construction of an alternative vertical mouth stretching orthosis for vertical microstomia. By using thermoplastic splinting material and a long thread screw, a vertical mouth-stretching orthosis can be custom-fit to any patient's mouth. The device can be fabricated for a pediatric or adult patient for the rehabilitation of a circumferential mouth burn, especially targeting the vertical diameter. When using this device, patients gave positive feedback for comfort and ease of use, with increased mouth mobility and range of motion. This vertical orthotic device provides an economical and comfortable alternative for vertical mouth diameter enlargement to the current five devices available in the literature. PMID:16679906

Davis, Shari; Thompson, Jarita G; Clark, Janet; Kowal-Vern, Areta; Latenser, Barbara A

2006-01-01

342

Vertical semiconducting single-walled carbon nanotube Schottky diode  

NASA Astrophysics Data System (ADS)

This paper presents a vertical semiconducting single-walled carbon nanotube (sSWCNT)-based Schottky device. For the first time, the author successfully demonstrated a vertical s-SWCNT Schottky diode on an anodized aluminum oxide (AAO) template. In the vertical pores of an AAO template s-SWCNTs were vertically grown and aligned. The vertical growth of s-SWCNTs inside the pores was achieved by successfully isolating the catalyst at the bottom of the pores by using redeposition enabled angled ion milling. The ends of the grown s-SWCNTs were coated with palladium and titanium to form Schottky and Ohmic contacts, respectively. The I-V characteristics of the vertical s-SWCNT paths engaging the Schottky and Ohmic contacts well demonstrated Schottky diode rectification.

Jung, Sunghwan

2014-07-01

343

Neural correlates of the Pythagorean ratio rules.  

PubMed

Millennia ago Pythagoras noted a simple but remarkably powerful rule for the aesthetics of tone combinations: pairs of tones--intervals--with simple ratios such as an octave (ratio 2 : 1) or a fifth (ratio 3 : 2) were pleasant sounding (consonant), whereas intervals with complex ratios such as the major seventh (ratio 243 : 128) were harsh (dissonant). These Pythagorean ratio rules are the building blocks of Western classical music; however, their neurophysiologic basis is not known. Using functional MRI we have found the neurophysiologic correlates of the ratio rules. In musicians, the inferior frontal gyrus, superior temporal gyrus, medial frontal gyrus, inferior parietal lobule and anterior cingulate respond with progressively more activation to perfect consonances, imperfect consonances and dissonances. In nonmusicians only the right inferior frontal gyrus follows this pattern. PMID:17885594

Foss, Alexander H; Altschuler, Eric L; James, Karin H

2007-10-01

344

Axisymmetric modes in vertically stratified self-gravitating discs  

Microsoft Academic Search

We carry out a linear analysis of the vertical normal modes of axisymmetric perturbations in stratified, compressible, self-gravitating gaseous discs in the shearing-box approximation. An unperturbed disc has a polytropic vertical structure that allows us to study specific dynamics for subadiabatic, adiabatic and superadiabatic vertical stratifications, by simply varying the polytropic index. In the absence of self-gravity, four well-known principal

G. R. Mamatsashvili; W. K. M. Rice

2010-01-01

345

Contribution of the vertical semicircular canals to the caloric nystagmus.  

PubMed

Modulation of the caloric nystagmus in response to repositioning the plane of one vertical semicircular canal from gravitational horizontal to vertical during continuous caloric stimulation was used to measure the vertical canal's contribution to the nystagmus. The rationale was to examine the thermovective response from one vertical canal at a time, after a temperature gradient had been established across its two limbs. The nystagmus was measured and analysed in three dimensions using orthogonal head-referenced coordinates. The magnitude of each semicircular canal's contribution to the overall caloric response, the canal vector, was determined in non-orthogonal, contravariant semicircular canal plane coordinates. By using the canal plane reorientation technique and contravariant canal plane coordinates, we were able to measure the proportional thermovective response magnitude generated by each vertical canal during caloric stimulation. We found that the anterior canal contributed about one-third and the posterior canal about one-tenth as much as the lateral canal did to the overall caloric response magnitude when it was reoriented from horizontal to vertical. Comparison of the eye rotation axis before and after each vertical canal plane reorientation, with the geometry of the stimulated semicircular canals, also showed directional modulation of the caloric nystagmus by the vertical canal response. When one vertical canal plane was horizontal during caloric stimulation, the eye rotation axis aligned with the resultant of the other vertical canal and the lateral canal response axes. After vertical canal plane reorientation, the eye rotation axis realigned towards the resultant of the maximally stimulated vertical canal and the lateral canal, by 55.2+/-33.9 degrees (mean+/-SD) after anterior canal plane reorientation and by 32.3+/-21.2 degrees after posterior canal reorientation. PMID:9840495

Aw, S T; Haslwanter, T; Fetter, M; Heimberger, J; Todd, M J

1998-09-01

346

Effect of neck pain on verticality perception: A cohort study  

Microsoft Academic Search

Grod JP, Diakow PR. Effect of neck pain on verticality perception: a cohort study. Arch Phys Med Rehabil 2002;83:412-5. Objective: To use the Rod-and-Frame Test (RFT) as a quantification of the perception of verticality in subjects with and without neck pain. Design: Cohort study comparing perception of verticality in symptomatic subjects with neck pain versus a control group. Setting: Both

Jaroslaw P. Grod; Peter R. Diakow

2002-01-01

347

Continuous Growth of Vertically Aligned Carbon Nanotubes Forests  

E-print Network

Vertically aligned carbon nanotubes are one of the most promising materials due their numerous applications in flexible electronic devices, biosensors and multifunctional aircraft materials, among others. However, the ...

Guzman de Villoria, Roberto

348

The effect of distributors on two-phase and three-phase flows in vertical columns  

E-print Network

of Distributors on Two-Phase and Three-Phase Flows in Vertical Columns. (May 1982) Chic-Jan Paul Ouyang, B. S. , Fu-Jen Catholic University Chairman of Advisory Committee: Dr. Gary B. Tatterson Two-phase air-water and three-phase air-water-solids flows have... of Gas Distributor. . . . . B) Ratio of Gas Hold-Up and Pressure Drop through Distributor. . C) Drift Flux 2. Three-Phase System. A) Solid Hold-Up. a) Effect of Gas Flow Rate. . . . . b) Effect of Liquid Flow Rate. . B) Gas Hold-Up. a} Effect...

Ouyang, Chie-Jan Paul

2012-06-07

349

Nickel Infiltration of Vertically Aligned Carbon Nanotube Forests via Pulsed Electro Deposition  

NASA Astrophysics Data System (ADS)

Carbon nanotube forests have been used as a template for building micro-scale high aspect ratio devices. Vertically aligned carbon nanotube forests are grown on a patterned catalyst, but these structures are extremely fragile. So we then infiltrate them with another material. For some devices, such as micro-filters for liquid and gas and micro-scale antennas the forest must be infiltrated with a metal, and we have developed a process using pulsed electro deposition of nickel to infiltrate these forests. We will present on mechanical and electrical characterization of the composite material and show device structures.

Barrett, Lawrence; Noyce, Steven; Davis, Robert

2012-10-01

350

Measurements of Aerosol Vertical Profiles and Optical Properties during INDOEX 1999 Using Micro-Pulse Lidars  

NASA Technical Reports Server (NTRS)

Micro-pulse lidar systems (MPL) were used to measure aerosol properties during the Indian Ocean Experiment (INDOEX) 1999 field phase. Measurements were made from two platforms: the NOAA ship RN Ronald H. Brown, and the Kaashidhoo Climate Observatory (KCO) in the Maldives. Sunphotometers were used to provide aerosol optical depths (AOD) needed to calibrate the MPL. This study focuses on the height distribution and optical properties (at 523 nm) of aerosols observed during the campaign. The height of the highest aerosols (top height) was calculated and found to be below 4 km for most of the cruise. The marine boundary layer (MBL) top was calculated and found to be less than 1 km. MPL results were combined with air mass trajectories, radiosonde profiles of temperature and humidity, and aerosol concentration and optical measurements. Humidity varied from approximately 80% near the surface to 50% near the top height during the entire cruise. The average value and standard deviation of aerosol optical parameters were determined for characteristic air mass regimes. Marine aerosols in the absence of any continental influence were found to have an AOD of 0.05 +/- 0.03, an extinction-to-backscatter ratio (S-ratio) of 33 +/- 6 sr, and peak extinction values around 0.05/km (near the MBL top). The marine results are shown to be in agreement with previously measured and expected values. Polluted marine areas over the Indian Ocean, influenced by continental aerosols, had AOD values in excess of 0.2, S-ratios well above 40 sr, and peak extinction values approximately 0.20/km (near the MBL top). The polluted marine results are shown to be similar to previously published values for continental aerosols. Comparisons between MPL derived extinction near the ship (75 m) and extinction calculated at ship-level using scattering measured by a nephelometer and absorption using a PSAP were conducted. The comparisons indicated that the MPL algorithm (using a constant S-ratio throughout the lower troposphere) calculates extinction near the surface in agreement with the ship-level measurements only when the MBL aerosols are well mixed with aerosols above. Finally, a review of the MPL extinction profiles showed that the model of aerosol vertical extinction developed during an earlier INDOEX field campaign (at the Maldives) did not correctly describe the true vertical distribution over the greater Indian Ocean region. Using the average extinction profile and AOD obtained during marine conditions, a new model of aerosol vertical extinction was determined for marine atmospheres over the Indian Ocean. A new model of aerosol vertical extinction for polluted marine atmospheres was also developed using the average extinction profile and AOD obtained during marine conditions influenced by continental aerosols.

Welton, Ellsworth J.; Voss, Kenneth J.; Quinn, Patricia K.; Flatau, Piotr J.; Markowicz, Krzysztof; Campbell, James R.; Spinhirne, James D.; Gordon, Howard R.; Johnson, James E.; Starr, David OC. (Technical Monitor)

2001-01-01

351

Vertically homogeneous stationary tornado-type vortex  

NASA Astrophysics Data System (ADS)

Tornado is regarded as one of the most dangerous atmosphere phenomena. The tornado phenomenon has been intensively studied so far, however, there is still no established and accepted theory of how tornadoes form, an uncertainty still exists concerning extreme winds and pressure drops in tornadoes. It is commonly accepted that it is possible to describe tornado from the set of nonlinear hydrodynamical equations, however, it is still unclear which non-linear processes are responsible for its formation. Nonlinear terms in the system are associated with either centrifugal force, or entropy transport, or transport of humidity. It appears that the amount and spatial distribution of precipitation with the convection are important indicators of the weather phenomena associated with a particular storm. The low-precipitation supercells that produce relatively little precipitation and yet show clear visual signs of rotation. Low-precipitation supercells occur most often near the surface dryline and, owing to the sparse precipitation and relatively dry environments with little cloudiness. Low-precipitation storms are frequently non-tornadic and many are non-severe despite exhibiting persistent rotation. On the other hand, the so-called high-precipitation storms are characterized by substantial precipitation within their mesocyclonic circulations. When high-precipitation storms have a recognizable hook radar echo, reflectivity in the hook is comparable to those in the precipitation core. High-precipitation supercells are probably the most common form of supercell and produce severe weather of all types including tornadoes. Therefore, in this work we consider a hydrodynamic system with only one nonlinear term associated with atmosphere humidity, which yields energy to the system. The tornado vortex is usually to a good approximation cylindrical so we use cylindrical geometry and homogeneity in vertical direction. In this case the problem reduces to a system of ordinary differential equations. Rotation in the vortex is associated with compressibility so we also take into account the compressibility of the gas. Under certain approximations the problem reduces to a single high-order nonlinear equation. Numerical solution of the obtained high-order equation describes all three velocity components and all thermodynamic parameters in the system. The system exhibits high rotation and strong vertical air flow in the middle part of the vortex.

Rutkevich, P. B.; Rutkevych, P. P.

2010-05-01

352

Development of Vertical Cable Seismic System (3)  

NASA Astrophysics Data System (ADS)

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 shot points and receiver points in the field include the errors. We use these data as initial guesses, we invert iteratively shot and receiver positions to match the travel time data. After several iterations we could finally estimate the most probable positions. Integration of the constraint of VCS hydrophone positions, such as the spacing is 10m, can accelerate the convergence of the iterative inversion and improve results. The accuracy of the estimated positions from the travel time date is enough for the VCS data processing.

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

2013-12-01

353

Vertical Cable Seismic Survey for SMS exploration  

NASA Astrophysics Data System (ADS)

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 hundred meters. Our VCS system has been demonstrated as a promising survey tool for the SMS exploration.

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

2014-05-01

354

The effect of sex ratios on suicide.  

PubMed

Whereas sex ratios are likely to affect the likelihood of marriage, how sex ratios affect health and survival is underexplored. This study uses suicide as a measure of mental health and examines how suicides are affected by sex ratios. As women tend to marry men older than themselves, shrinking populations will lead to higher sex ratios (i.e., higher proportions of men) in the marriage market. Using data from Japan, I find that high sex ratios, both early-life and current, are correlated with higher male suicide rates, whereas female suicide rates are generally not affected. The results of this study have important implications for public health in countries where imbalanced sex ratios are a concern. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23943552

Kuroki, Masanori

2014-12-01

355

Midrapidity Antiproton-to-Proton Ratio in pp Collisons root s=0.9 and 7 TeV Measured by the ALICE Experiment  

Microsoft Academic Search

The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at root s = 0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45 < p(t) < 1.05 GeV\\/c and rapidity vertical bar y vertical bar < 0.5. The

K. Aamodt; N. Abel; U. Abeysekara; A. A. Quintana; A. Abramyan; D. Adamova; M. M. Aggarwal; G. A. Rinella; A. G. Agocs; S. A. Salazar; Z. Ahammed; A. Ahmad; N. Ahmad; S. U. Ahn; R. Akimoto; A. Akindinov; D. Aleksandrov; B. Alessandro; R. A. Molina; A. Alici; E. A. Avina; J. Alme; T. Alt; V. Altini; S. Altinpinar; C. Andrei; A. Andronic; G. Anelli; V. Angelov; C. Anson; T. Anticic; F. Antinori; S. Antinori; K. Antipin; D. Antonczyk; P. Antonioli; A. Anzo; L. Aphecetche; S. A. Appelshauser; S. Arcelli; R. Arceo; A. Arend; N. Armesto; R. Arnaldi; T. Aronsson; I. C. Arsene; A. Asryan; A. Augustinus; R. Averbeck; T. C. Awes; J. Aysto; M. D. Azmi; S. Bablok; M. Bach; A. Badala; Y. W. Baek; S. Bagnasco; R. Bailhache; R. Bala; A. Baldisser; A. Baldit; J. Ban; R. Barbera; G. G. Barnafoldi; L. S. Barnby; V. Barret; J. Bartke; F. Barile; M. Basile; V. Basmanov; N. Bastid; B. Bathen; G. Batigne; B. Batyunya; C. Baumann; I. G. Bearden; B. Becker; I. Belikov; R. Bellwied; E. Belmont-Moreno; A. Belogianni; L. Benhabib; S. Beole; I. Berceanu; A. Bercuci; E. Berdermann; Y. Berdnikov; L. Betev; A. Bhasin; A. K. Bhati; L. Bianchi; N. Bianchi; C. Bianchin; J. Bielcik; J. Bielcikova; A. Bilandzic; L. Bimbot; E. Biolcati; A. Blanc; F. Blanco; D. Blau; C. Blume; M. Boccioli; N. Bock; A. Bogdanov; H. Boggild; M. Bogolyubsky; J. Bohm; L. Boldizsar; M. Bombara; C. Bombonati; M. Bondila; H. Borel; A. Borisov; C. Bortolin; S. Bose; L. Bosisio; F. Bossu; M. Botje; S. Bottger; G. Bourdaud; B. Boyer; M. Braun; P. Braun-Munzinger; L. Bravina; M. Bregant; T. Breitner; G. Bruckner; R. Brun; E. Bruna; G. E. Bruno; D. Budnikov; H. Buesching; P. Buncic; O. Busch; Z. Buthelezi; D. Caffarri; X. Cai; H. Caines; E. Calvo; E. Camacho; P. Camerini; M. Campbell; V. C. Roman; G. P. Capitani; G. C. Romeo; F. Carena; W. Carena; F. Carminati; A. C. Diaz; M. Caselle; J. C. Castellanos; J. F. C. Hernandez; V. Catanescu; E. Cattaruzza; C. Cavicchioli; P. Cerello; V. Chambert; B. Chang; S. Chapeland; A. Charpy; J. L. Charvet; S. Chattopadhyay; M. Cherney; C. Cheshkov; B. Cheynis; E. Chiavassa; V. C. Barroso; D. D. Chinellato; P. Chochula; K. Choi; M. Chojnacki; P. Christakoglou; C. H. Christensen; P. Christiansen; T. Chujo; F. Chuman; C. Cicalo; L. Cifarelli; F. Cindolo; J. Cleymans; O. Cobanoglu; J. P. Coffin; S. Coli; A. Colla; G. C. Balbastre; Z. C. del Valle; E. S. Conner; P. Constantin; G. Contin; J. G. Contreras; Y. C. Morales; T. M. Cormier; P. Cortese; I. C. Maldonado; M. R. Cosentino; F. Costa; M. E. Cotallo; E. Crescio; P. Crochet; E. Cuautle; L. Cunqueiro; J. Cussonneau; A. Dainese; H. H. Dalsgaard; A. Danu; I. Das; A. Dash; S. Dash; G. O. V. de Barros; A. de Caro; G. de Cataldo; J. de Cuveland; A. De Falco; M. De Gaspari; J. de Groot; D. De Gruttola; N. De Marco; S. De Pasquale; R. De Remigis; R. de Rooij; G. de Vaux; H. Delagrange; Y. Delgado; G. Dellacasa; A. Deloff; V. Demanov; E. Denes; A. Deppman; G. DErasmo; D. Derkach; A. Devaux; D. Di Bari; C. Di Giglio; S. Di Liberto; A. Di Mauro; P. Di Nezza; M. Dialinas; L. Diaz; R. Diaz; T. Dietel; R. Divia; O. Djuvsland; V. Dobretsov; A. Dobrin; T. Dobrowolski; B. Donigus; I. Dominguez; D. M. M. Don; O. Dordic; A. K. Dubey; J. Dubuisson; L. Ducroux; P. Dupieux; A. K. D. Majumdar; M. R. D. Majumdar; D. Elia; D. Emschermann; A. Enokizono; B. Espagnon; M. Estienne; S. Esumi; D. Evans; S. Evrard; G. Eyyubova; C. W. Fabjan; D. Fabris; J. Faivre; D. Falchieri; A. Fantoni; M. Fasel; O. Fateev; R. Fearick; A. Fedunov; D. Fehlker; V. Fekete; D. Felea; B. Fenton-Olsen; G. Feofilov; A. F. Tellez; E. G. Ferreiro; A. Ferretti; R. Ferretti; M. A. S. Figueredo; S. Filchagin; R. Fini; F. M. Fionda; E. M. Fiore; M. Floris; Z. Fodor; S. Foertsch; P. Foka; S. Fokin; F. Formenti; E. Fragiacomo; M. Fragkiadakis; U. Frankenfeld; A. Frolov; U. Fuchs; F. Furano; C. Furget; M. F. Girard; J. J. Gaardhoje; S. Gadrat; M. Gagliardi; A. Gago; M. Gallio; P. Ganoti; M. S. Ganti; C. Garabatos; C. G. Trapaga; J. Gebelein; R. Gemme; M. Germain; A. Gheata; M. Gheata; B. Ghidini; P. Ghosh; G. Giraudo; P. Giubellino; E. Gladysz-Dziadus; R. Glasow; P. Glassel; A. Glenn; R. G. Jimenez; H. G. Santos; L. H. Gonzalez-Trueba; P. Gonzalez-Zamora; S. Gorbunov; Y. Gorbunov; S. Gotovac; H. Gottschlag; V. Grabski; R. Grajcarek; A. Grelli; A. Grigoras; C. Grigoras; V. Grigoriev; A. Grigoryan; S. Grigoryan; B. Grinyov; N. Grion; P. Gros; J. F. Grosse-Oetringhaus; J. Y. Grossiord; R. Grosso; F. Guber; R. Guernane; C. Guerra; B. Guerzoni; K. Gulbrandsen; H. Gulkanyan; T. Gunji; A. Gupta; R. Gupta; H. A. Gustafsson; H. Gutbrod; O. Haaland; C. Hadjidakis; M. Haiduc; H. Hamagaki; G. Hamar; J. Hamblen; B. H. Han; J. W. Harris; M. Hartig; A. Harutyunyan; D. Hasch; D. Hasegan; D. Hatzifotiadou; A. Hayrapetyan; M. Heide; M. Heinz; H. Helstrup; A. Herghelegiu; C. Hernandez; G. H. Corral; N. Herrmann; K. F. Hetland

2010-01-01

356

A theoretical analysis of vertical flow equilibrium  

SciTech Connect

The assumption of Vertical Flow Equilibrium (VFE) and of parallel flow conditions, in general, is often applied to the modeling of flow and displacement in natural porous media. However, the methodology for the development of the various models is rather intuitive, and no rigorous method is currently available. In this paper, we develop an asymptotic theory using as parameter the variable R{sub L} = (L/H){radical}(k{sub V})/(k{sub H}). It is rigorously shown that present models represent the leading order term of an asymptotic expansion with respect to 1/R{sub L}{sup 2}. Although this was numerically suspected, it is the first time that is is theoretically proved. Based on the general formulation, a series of models are subsequently obtained. In the absence of strong gravity effects, they generalize previous works by Zapata and Lake (1981), Yokoyama and Lake (1981) and Lake and Hirasaki (1981), on immiscible and miscible displacements. In the limit of gravity-segregated flow, we prove conditions for the fluids to be segregated and derive the Dupuit and Dietz (1953) approximations. Finally, we also discuss effects of capillarity and transverse dispersion.

Yortsos, Y.C.

1992-01-01

357

Vertical landscraping, a big regionalism for Dubai.  

PubMed

Dubai's ecologic and economic complications are exacerbated by six years of accelerated expansion, a fixed top-down approach to urbanism and the construction of iconic single-phase mega-projects. With recent construction delays, project cancellations and growing landscape issues, Dubai's tower typologies have been unresponsive to changing environmental, socio-cultural and economic patterns (BBC, 2009; Gillet, 2009; Lewis, 2009). In this essay, a theory of "Big Regionalism" guides an argument for an economically and ecologically linked tower typology called the Condenser. This phased "box-to-tower" typology is part of a greater Landscape Urbanist strategy called Vertical Landscraping. Within this strategy, the Condenser's role is to densify the city, facilitating the creation of ecologic voids that order the urban region. Delineating "Big Regional" principles, the Condenser provides a time-based, global-local urban growth approach that weaves Bigness into a series of urban-regional, economic and ecological relationships, builds upon the environmental performance of the city's regional architecture and planning, promotes a continuity of Dubai's urban history, and responds to its landscape issues while condensing development. These speculations permit consideration of the overlooked opportunities embedded within Dubai's mega-projects and their long-term impact on the urban morphology. PMID:21132951

Wilson, Matthew

2010-01-01

358

Vertical transmission of Theileria lestoquardi in sheep.  

PubMed

This is the first report of an outbreak of Theileria lestoquardi abortion and stillbirth in a mob of 450 ewes in July 2012, during which, approximately 35 late-term ewes lost their fetuses over a 5-day period. A dead ewe and her aborted fetus were transported to the Ahvaz Veterinary Hospital for the diagnostic evaluation. The microbial cultures from the ewe vaginal discharges and fetal abomasal contents and the liver were negative. The blood films of the ewe and her fetus contained Theileria piroplasms and the impression smears from ewe liver and fetal spleen were positive for Theileria Koch blue bodies. The DNA was extracted from the liver and spleen of ewe and her fetus, respectively, and analyzed by polymerase chain reaction (PCR) using specific primers derived from the nucleotide sequences of 18S ribosomal DNA (rDNA) gene of T. lestoquardi. A single fragment of 428-bp fragment was amplified. The PCR product was directly sequenced and the alignment of the sequence with similar sequences in GenBank(®) showed 100% identities with 18S rDNA gene of T. lestoquardi. The present study is the first report of the T. lestoquardi vertical transmission that could be related to the abortion. PMID:24813745

Zakian, Amir; Nouri, Mohammad; Barati, Farid; Kahroba, Hooman; Jolodar, Abbas; Rashidi, Fardokht

2014-07-14

359

Vertical extensions of galactic spiral arms  

NASA Technical Reports Server (NTRS)

The vertical structure of the large scale galactic shock along spiral arms is studied in order to understand the extended features or the wings of spiral arms observed by Kepner (1970) and recently checked by Soukup (1979). Numerical calculations of two-dimensional gas flow were performed for two models of the gas. The results show that the shock front, standing perfectly perpendicular to the galactic plane, extends impressively above the scale height of the interstellar gas. In the extreme case of isothermal gas, the shock solution exists at any distance from the plane. In a realistic model in which the kinetic temperature of the gas is stratified, increasing with height, the shock can extend up to 700 pc. For both models, although the velocity component perpendicular to the galactic plane is small, the solutions corresponding to layered one-dimensional flow contain no shocks at such heights. In order to study the geometry of the shock front and the flow pattern near it, a simplified model is adopted, in which the Coriolis force is neglected. However, estimates show that including it will enhance the shock strength. The compression at the shock front makes the gas observable at high latitudes.

Soukup, J. E.; Yuan, C.

1981-01-01

360

Morpheus Vertical Test Bed Flight Testing  

NASA Technical Reports Server (NTRS)

NASA's Morpheus Project has developed and tested a prototype planetary lander capable of vertical takeoff and landing, that is designed to serve as a testbed for advanced spacecraft technologies. The lander vehicle, propelled by a LOX/Methane engine and sized to carry a 500kg payload to the lunar surface, provides a platform for bringing technologies from the laboratory into an integrated flight system at relatively low cost. Morpheus onboard software is autonomous from ignition all the way through landing, and is designed to be capable of executing a variety of flight trajectories, with onboard fault checks and automatic contingency responses. The Morpheus 1.5A vehicle performed 26 integrated vehicle test flights including hot-fire tests, tethered tests, and two attempted freeflights between April 2011 and August 2012. The final flight of Morpheus 1.5A resulted in a loss of the vehicle. In September 2012, development began on the Morpheus 1.5B vehicle, which subsequently followed a similar test campaign culminating in free-flights at a simulated planetary landscape built at Kennedy Space Center's Shuttle Landing Facility. This paper describes the integrated test campaign, including successes and setbacks, and how the system design for handling faults and failures evolved over the course of the project.

Hart, Jeremy; Devolites, Jennifer

2014-01-01

361

Radon 222 and tropospheric vertical transport  

SciTech Connect

Radon 222 is an inert gas whose loss is due only to radioactive decay with a half life of 3.83 days (5.51-day ''exponential'' lifetime). It is a very useful tracer of continental air because only ground level continental sources are significant. Thus it is similar in several ways to many air pollutants (e.g., NO/sub x/) (NO+NO/sub 2/), SO/sub 2/, and certain hydrocarbons. Previously published measured /sup 222/Rn profiles are analyzed here by averaging for the summer, winter, and spring-fall seasons. The analysis shows that in summer, about 55% of the /sup 222/Rn is transported above the planetary boundary layer, considerably more than during the other seasons. Similarly, in summer, about 20% rises to over 5.5 km (500 mbar). The average profiles have been used to derive vertical eddy diffusion coefficients with maximum values of 5-7 x 10/sup 5/ cm/sup 2/ s/sup -1/ in the midtroposphere and 8 x 10/sup 3/ to 5 x 10/sup 4/ cm/sup 2/ s/sup -1/ near the surface.

Liu, S.C.; McAfee, J.R.; Cicerone, R.J.

1984-08-20

362

The vertical oscillations of coupled magnets  

NASA Astrophysics Data System (ADS)

The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for high school students. This paper is adapted from the winning solution to Problem 14, Magnetic Spring, as presented in the final round of the 23rd IYPT in Vienna, Austria. Two magnets were arranged on top of each other on a common axis. One was fixed, while the other could move vertically. Various parameters of interest were investigated, including the effective gravitational acceleration, the strength, size, mass and geometry of the magnets, and damping of the oscillations. Despite its simplicity, this setup yielded a number of interesting and unexpected relations. The first stage of the investigation was concerned only with the undamped oscillations of small amplitudes, and the period of small amplitude oscillations was found to be dependent only on the eighth root of important magnet properties such as its strength and mass. The second stage sought to investigate more general oscillations. A numerical model which took into account magnet size, magnet geometry and damping effects was developed to model the general oscillations. Air resistance and friction were found to be significant sources of damping, while eddy currents were negligible.

Kewei, Li; Jiahuang, Lin; Yang, Kang Zi; Liang, Samuel Yee Wei; Wong Say Juan, Jeremias

2011-07-01

363

Vertical profile measurements of lower troposphere ionisation  

NASA Astrophysics Data System (ADS)

Vertical soundings of the atmospheric ion production rate have been obtained from Geiger counters integrated with conventional meteorological radiosondes. In launches made from Reading (UK) during 2013-2014, the Regener-Pfotzer ionisation maximum was at an altitude equivalent to a pressure of (63.1±2.4) hPa, or, expressed in terms of the local air density, (0.101±0.005) kg m-3. The measured ionisation profiles have been evaluated against the Usoskin-Kovaltsov model and, separately, surface neutron monitor data from Oulu. Model ionisation rates agree well with the observed cosmic ray ionisation below 20 km altitude. Above 10 km, the measured ionisation rates also correlate well with simultaneous neutron monitor data, although, consistently with previous work, measured variability at the ionisation maximum is greater than that found by the neutron monitor. However, in the lower atmosphere (below 5 km altitude), agreement between the measurements and simultaneous neutron monitor data is poor. For studies of transient lower atmosphere phenomena associated with cosmic ray ionisation, this indicates the need for in situ ionisation measurements and improved lower atmosphere parameterisations.

Harrison, R. G.; Nicoll, K. A.; Aplin, K. L.

2014-11-01

364

Vertical cavity single quantum well laser  

SciTech Connect

We have achieved room-temperature pulsed and cw lasing at 980 nm in an optically pumped vertical cavity structure grown by molecular beam epitaxy containing only a single quantum well (SQW) of In/sub 0.2/Ga/sub 0.8/As. Limited gain due to the extreal phase lock loop. The relative timing jitter was measured using the error voltage of the feedback loop which has a 5 kHz bandwidth. This technique of measuring the relative timing jitter is accurate since the frequencies of all the timing fluctuations fall within the loop bandwidth. The novel element in the implementation of the pulsed optical phase lock loop is the time delay dimely short active material length of 80 A implies that losses due to absorption, scattering, and mirror transmission are extremely low. Using 10 ps pump pulses at 860 or 880 nm, the estimated energy density absorbed in the spacer was /similar to/12 fJ//mu/m/sup 2/ at threshold, indicating a carrier density approximately four times that required for transparency. Continuous wave pumping yielded an estimated threshold absorbed intensity of /similar to/7 /mu/W//mu/m/sup 2/.

Jewell, J. L.; Huang, K. F.; Tai, K.; Lee, Y. H.; Fischer, R. J.; McCall, S. L.; Cho, A. Y.

1989-07-31

365

Mechanical model of vertical nanowire cell penetration.  

PubMed

Direct access into cells' interiors is essential for biomolecular delivery, gene transfection, and electrical recordings yet is challenging due to the cell membrane barrier. Recently, molecular delivery using vertical nanowires (NWs) has been demonstrated for introducing biomolecules into a large number of cells in parallel. However, the microscopic understanding of how and when the nanowires penetrate cell membranes is still lacking, and the degree to which actual membrane penetration occurs is controversial. Here we present results from a mechanical continuum model of elastic cell membrane penetration through two mechanisms, namely through "impaling" as cells land onto a bed of nanowires, and through "adhesion-mediated" penetration, which occurs as cells spread on the substrate and generate adhesion force. Our results reveal that penetration is much more effective through the adhesion mechanism, with NW geometry and cell stiffness being critically important. Stiffer cells have higher penetration efficiency, but are more sensitive to NW geometry. These results provide a guide to designing nanowires for applications in cell membrane penetration. PMID:24237230

Xie, Xi; Xu, Alexander M; Angle, Matthew R; Tayebi, Noureddine; Verma, Piyush; Melosh, Nicholas A

2013-01-01

366

Functionalization of vertically aligned carbon nanotubes  

PubMed Central

Summary 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. PMID:23504581

Snyders, Rony; Colomer, Jean-Francois

2013-01-01

367

Jetting during vertical impacts of spherical projectiles  

NASA Astrophysics Data System (ADS)

The extreme pressures reached during jetting, a process by which material is squirted out from the contact point of two colliding objects, causes melting and vaporization at low impact velocities. Jetting is a major source of melting in shocked porous material, a potential source of tektites, a possible origin of chondrules, and even a conceivable origin of the Moon. Here, in an attempt to quantify the importance of jetting, we present numerical simulation of jetting during the vertical impacts of spherical projectiles on both flat and curved targets. We find that impacts on curved targets result in more jetted material but that higher impact velocities result in less jetted material. For an aluminum impactor striking a flat Al target at 2 km/s we find that 3.4% of a projectile mass is jetted while 8.3% is jetted for an impact between two equal sized Al spheres. Our results indicate that the theory of jetting during the collision of thin plates can be used to predict the conditions when jetting will occur. However, we find current analytic models do not make accurate predictions of the amount of jetted mass. Our work indicates that the amount of jetted mass is independent of model resolution as long as some jetted material is resolved. This is the result of lower velocity material dominating the mass of the jet.

Johnson, B. C.; Bowling, T. J.; Melosh, H. J.

2014-08-01

368

Portland. Correct lighting, x2 vertical exaggeration  

NSDL National Science Digital Library

Portland. Correct lighting, x2 vertical exaggeration w-Mt. Hood and Mt. Adams. These scenes show Portland, Oregon and the countryside around it as seen by the Landsat Thematic Mapper (TM) instrument. Portland sits on the Willamette River south of its confluence with the Columbia River. The city sits very close to several mountains in the Cascade Range, including Mt. Hood, Mt. Adams, and Mt. St. Helens. The terrain of the area is also shown exaggerated by a factor of two to emphasis terrain features such as the mountains and the Columbia Gorge just north of Mt. Hood and south of Mt. Adams. The shortwave infrared (TM band 5), infrared (TM band 4), and visible green (TM band 2) channels are displayed in the images as red, green, and blue respectively. In this combination, barren and-or recently cultivated land appears red to pink, vegetation appears green, water is dark blue, and artificial structures of concrete and asphalt appear dark grey or black. The natural color images combine TM bands 3, 2, and 1 and map them to red, green, and blue respectively.

Allen, Jesse; Williams, Darrel

1999-04-09

369

TURBULENCE IN THE OUTER REGIONS OF PROTOPLANETARY DISKS. II. STRONG ACCRETION DRIVEN BY A VERTICAL MAGNETIC FIELD  

SciTech Connect

We carry out a series of local, vertically stratified shearing box simulations of protoplanetary disks that include ambipolar diffusion and a net vertical magnetic field. The ambipolar diffusion profiles we employ correspond to 30 AU and 100 AU in a minimum mass solar nebula (MMSN) disk model, which consists of a far-ultraviolet-ionized surface layer and low-ionization disk interior. These simulations serve as a follow-up to Simon et al., in which we found that without a net vertical field, the turbulent stresses that result from the magnetorotational instability (MRI) are too weak to account for observed accretion rates. The simulations in this work show a very strong dependence of the accretion stresses on the strength of the background vertical field; as the field strength increases, the stress amplitude increases. For a net vertical field strength (quantified by ?{sub 0}, the ratio of gas to magnetic pressure at the disk mid-plane) of ?{sub 0} = 10{sup 4} and ?{sub 0} = 10{sup 5}, we find accretion rates M-dot ?10{sup -8}-10{sup –7} M{sub ?} yr{sup –1}. These accretion rates agree with observational constraints, suggesting a vertical magnetic field strength of ?60-200 ?G and 10-30 ?G at 30 AU and 100 AU, respectively, in a MMSN disk. Furthermore, the stress has a non-negligible component due to a magnetic wind. For sufficiently strong vertical field strengths, MRI turbulence is quenched, and the flow becomes largely laminar, with accretion proceeding through large-scale correlations in the radial and toroidal field components as well as through the magnetic wind. In all simulations, the presence of a low-ionization region near the disk mid-plane, which we call the ambipolar damping zone, results in reduced stresses there.

Simon, Jacob B.; Armitage, Philip J.; Beckwith, Kris [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309-0440 (United States); Bai, Xue-Ning [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States); Stone, James M., E-mail: jbsimon@jila.colorado.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-09-20

370

Factorization of cubic vertices involving three different higher spin fields  

NASA Astrophysics Data System (ADS)

We derive a class of cubic interaction vertices for three higher spin fields, with integer spins ?1, ?2, ?3, by closing commutators of the Poincaré algebra in four-dimensional flat spacetime. We find that these vertices exhibit an interesting factorization property which allows us to identify off-shell perturbative relations between them.

Akshay, Y. S.; Ananth, Sudarshan

2014-10-01

371

Characteristics Of Vertical Mantle Heat Exchangers For Solar Water Heaters  

Microsoft Academic Search

The flow structure in vertical mantle heat exchangers was investigated using a full-scale tank designed to facilitate flow visualisation. The flow structure and velocities in the mantle were measured using a particle Image Velocimetry (PIV) system. A CFD simulation model of vertical mantle heat exchangers was also developed for detailed evaluation of the heat flux distribution over the mantle surface.

L. J. Shah; G. L. Morrison; M. Behnia

1999-01-01

372

IMPROVING VERTICAL COORDINATION OF AGRICULTURAL INDUSTRIES THROUGH SUPPLY CHAIN MANAGEMENT  

Microsoft Academic Search

Supply chain management is an important topic related to improving efficiency, vertical coordination, overall performance and competitiveness in food industries. Considerable attention has been given to supply chain management as an approach for improving vertical coordination and market performance in both the trade literature and by food economists. Much of this has been primarily from the perspective of grocery retailer-wholesalers,

Donald J. Ricks; Timothy A. Woods; James A. Sterns

1999-01-01

373

Effects of Vertical Scaling Methods on Linear Growth Estimation  

ERIC Educational Resources Information Center

Vertical scaling is necessary to facilitate comparison of scores from test forms of different difficulty levels. It is widely used to enable the tracking of student growth in academic performance over time. Most previous studies on vertical scaling methods assume relatively long tests and large samples. Little is known about their performance when…

Lei, Pui-Wa; Zhao, Yu

2012-01-01

374

RECENT IMPROVEMENTS IN VERTICAL ORBIT FEEDBACK AT THE DARESBURY SRS  

Microsoft Academic Search

A vertical orbit feedback system has been in routine operation at Daresbury since 1994 and plays an important role in providing stable beams for users. This system was based, until recently, on a local feedback scheme, which stabilised the vertical orbit at each line using a single photon monitor and a closed three magnet bump. This paper reports the improvements

S. L. Smith

375

NATURAL CONVECTION OF SUBCOOLED LIQUID NITROGEN IN A VERTICAL CAVITY  

E-print Network

NATURAL CONVECTION OF SUBCOOLED LIQUID NITROGEN IN A VERTICAL CAVITY Yeon SukChoi \\ Steven W. Van to measure the natural convection of subcooled liquid nitrogen between two vertical plates has been performed power transformer cooled by natural convection of subcooled liquid nitrogen. A liquid nitrogen bath

Chang, Ho-Myung

376

ELECTROTHERMAL SCS MICROMIRROR WITH LARGE-VERTICAL-DISPLACEMENT ACTUATION  

E-print Network

the mirror plate to remain parallel to the substrate surface, while still taking advantage of the largeELECTROTHERMAL SCS MICROMIRROR WITH LARGE-VERTICAL-DISPLACEMENT ACTUATION Ankur Jain, Hongwei Qu a vertical displacement of 0.2 mm at an actuation voltage of 6 V d.c. This device can also perform

Bowers, John

377

Half-State Readout In Vertical-Bloch-Line Memory  

NASA Technical Reports Server (NTRS)

Potentially narrow margins of chirality-based chopping of magnetic stripes avoided. Half-state readout is experimental method of readout in Vertical-Bloch-Line (VBL) memory. Based on differential deflections of magnetic stripe domains in which data bits stored. To give meaning to explanation of half-state readout, see "Vertical-Bloch-Line Memory" (NPO-18467).

Katti, Romney R.; Wu, Jiin-Chuan; Stadler, Henry L.

1994-01-01

378

SOLVING SIMPLE STOCHASTIC GAMES WITH FEW RANDOM VERTICES  

E-print Network

of the behaviour of the user. The main algorithmic problem about SSGs is the computation of values of the verticesSOLVING SIMPLE STOCHASTIC GAMES WITH FEW RANDOM VERTICES HUGO GIMBERT AND FLORIAN HORN LaBRI, CNRS.horn@cwi.nl Abstract. Simple stochastic games are two-player zero-sum stochastic games with turn- based moves, perfect

Paris-Sud XI, Université de

379

Determinants of International Vertical Specialization and Implications on Technology Spillovers  

Microsoft Academic Search

This paper examines the determinants of vertical specialization choices and the implications of those different choices on international technology diffusion. Vertical specialization is a dominant feature of the international economy, it can take place through FDI and intra-firm trade as well as through arm's length import strategy. Following the models of Grossman and Helpman (2002) and of Antras and Helpman

Liza JABBOUR

380

Modelling vertical and lateral seed bank movements during mouldboard ploughing  

Microsoft Academic Search

The vertical distribution of weed seeds in the soil is of fundamental importance because seedling emergence depends on seed depth. The lateral displacement of the earth during mouldboard ploughing contributes to the dispersal of the weeds inside the tilled field. In order to model vertical and lateral seed displacements during ploughing, an existing model describing soil particle movements for different

Nathalie Colbach; Jean Roger-Estrade; Bruno Chauvel; Jacques Caneill

2000-01-01

381

Experimental Vertical Stability Studies for ITER Performance and Design Guidance  

SciTech Connect

Operating experimental devices have provided key inputs to the design process for ITER axisymmetric control. In particular, experiments have quantified controllability and robustness requirements in the presence of realistic noise and disturbance environments, which are difficult or impossible to characterize with modeling and simulation alone. This kind of information is particularly critical for ITER vertical control, which poses some of the highest demands on poloidal field system performance, since the consequences of loss of vertical control can be very severe. The present work describes results of multi-machine studies performed under a joint ITPA experiment on fundamental vertical control performance and controllability limits. We present experimental results from Alcator C-Mod, DIII-D, NSTX, TCV, and JET, along with analysis of these data to provide vertical control performance guidance to ITER. Useful metrics to quantify this control performance include the stability margin and maximum controllable vertical displacement. Theoretical analysis of the maximum controllable vertical displacement suggests effective approaches to improving performance in terms of this metric, with implications for ITER design modifications. Typical levels of noise in the vertical position measurement which can challenge the vertical control loop are assessed and analyzed.

Humphreys, D A; Casper, T A; Eidietis, N; Ferrera, M; Gates, D A; Hutchinson, I H; Jackson, G L; Kolemen, E; Leuer, J A; Lister, J; LoDestro, L L; Meyer, W H; Pearlstein, L D; Sartori, F; Walker, M L; Welander, A S; Wolfe, S M

2008-10-13

382

Vertical Velocities in a Thunderstorm Gust Front and Outflow.  

NASA Astrophysics Data System (ADS)

Continuous vertically pointing measurements of a thunderstorm outflow, including its gust front, were obtained with a Doppler radar near New Salem, North Dakota. The measurements provide a high-resolution depiction of the vertical structure of reflectivity and vertical velocity within the gust front, the outflow, and the parent storm. Earlier gust front remote sensing studies have used Doppler observations obtained with low-elevation-angle scans to accurately measure the horizontal flow pattern from which vertical velocities were subsequently estimated by integrating the continuity equation. In contrast, the New Salem case provides direct, rather than derived, Doppler measurement of vertical velocities with better vertical resolution and vastly superior temporal resolution. The gust front's vertical structure is in general agreement with earlier observations and numerical simulations, except that the transition from strong upward to strong downward motion was more abrupt. The maximum updraft, of almost 10 m s1, was measured in the gust front at 1.35 km above ground level and was followed by equally strong downward motion only 1 min later at a slightly higher altitude.The observations support the earlier use of the continuity method for deriving the basic pattern of vertical motions in density currents from quasi-horizontal scan data.

Martner, Brooks E.

1997-05-01

383

Estimation of spinal loading in vertical vibrations by numerical simulation  

Microsoft Academic Search

Objective. This paper describes the prediction of spinal forces in car occupants during vertical vibrations using a numerical multi-body occupant model.Background. An increasing part of the population is exposed to whole body vibrations in vehicles. In literature, vertical vibrations and low back pain are often related to each other. The cause of these low back pains is not well understood.

M. M Verver; J van Hoof; C. W. J Oomens; N van de Wouw; J. S. H. M Wismans

2003-01-01

384

Dual-band operation vertical patch antenna for WLAN applications  

Microsoft Academic Search

In this paper, a novel design of the dual-band operation vertical patch antenna are proposed. The structure of proposed antenna consists of two vertical patches which is different from the architecture of traditional planar antennas. By utilizing the broadband feeding mechanism, the antenna bandwidth is significantly increased. And, two separate wide resonant modes for WLAN applications can be generated by

Kuo-Chien Chao; Fa-Shian Chang; Hong-Twu chen; Chia-Hung Lu; Yung-Tao Liu

2007-01-01

385

A Vertical Patch Antenna for Dual-Band Operation  

Microsoft Academic Search

A new dual-band vertical patch antenna for broadside radiation is described. The antenna is fed by a proximity-coupled probe, which maintains the advantages of the original single-band vertical patch antenna, such as small size, wide bandwidth and simple structure. The achieved bandwidths are 7% and 26%, respectively, at the lower and upper frequency bands.

Ka-Lam Lau; Hang Wong; Chi-Lun Mak; Kwai-man Luk; Kai-Fong Lee

2006-01-01

386

A dual-band vertical patch antenna with size reduction  

Microsoft Academic Search

A new feeding technique is proposed for the newly invented vertical patch antenna (VPA) for single and dual band operations. The new feeding method reduces the projection area and remains simple in structure and wide bandwidth, while the dual-band VPA maintains the advantages of the single-band vertical patch antenna, such as small size, wideband and simple structure

Ka-lam Lau; Hang Wong; Chi-lun Mak; Kwai-man Luk; Kai-Fong Lee

2005-01-01

387

A wideband C-shaped vertical patch antenna  

Microsoft Academic Search

A wideband vertical patch antenna (VPA) is depicted, which is devised from a single circular vertical patch. Without increasing the projection area, a C-shaped proximity-coupled fed VPA with 40% bandwidth and over 6 dBi gain across entire frequency band is designed and tested. Stable and broadside patterns are maintained across the matching band.

Ka-lam Lau; Kwai-man Luk; Kai-fong Lee

2006-01-01

388

A vertical antenna made of transposed sections of coaxial cable  

Microsoft Academic Search

A vertical array of colinear vertical dipoles is made of a series of sections of solid-dielectric coaxial cable with their inner and outer conductors transposed at each junction. Each section has an effective length of 1\\/2 wavelength in the cable, so the radiating gaps between the sections are all excited in the same polarity. A model designed for 450 Mc

H. Wheeler

1956-01-01

389

Southern California Earthquake Center Geologic Vertical Motion Database  

Microsoft Academic Search

The Southern California Earthquake Center Geologic Vertical Motion Database (VMDB) integrates disparate sources of geologic uplift and subsidence data at 104- to 106-year time scales into a single resource for investigations of crustal deformation in southern California. Over 1800 vertical deformation rate data points in southern California and northern Baja California populate the database. Four mature data sets are now

Nathan A. Niemi; Michael Oskin; Thomas K. Rockwell

2008-01-01

390

STUDY OF ABNORMAL VERTICAL EMITTANCE GROWTH IN ATF EXTRACTION LINE  

E-print Network

STUDY OF ABNORMAL VERTICAL EMITTANCE GROWTH IN ATF EXTRACTION LINE M. Alabau Pons, IFIC (CSIC, CERN, Geneva, Switzerland Abstract Since several years, the vertical beam emittance mea- sured the emittance measured in the DR itself, and there are indications that it grows rapidly with increasing beam

Paris-Sud XI, Université de

391

Human visual and vestibular heading perception in the vertical planes.  

PubMed

Heading estimation has not previously been reported in the vertical planes. This is a potentially interesting issue because although distribution of neuronal direction sensitivities is near uniform for vertical headings, there is an overrepresentation of otolith organs sensitive to motion in the horizontal relative to the vertical plane. Furthermore, thresholds of horizontal motion perception are considerably lower than those of vertical motion which has the potential to bias heading perception. The current data from 14 human subjects (age 19 to 67) measured heading estimation in response to vestibular motion of 14 cm (28 cm/s) over a 360° of headings at 5° intervals. An analogous visual motion was tested in separate trials. In this study, earth and head vertical/horizontal were always aligned. Results demonstrated that the horizontal component of heading was overestimated relative to the vertical component for vestibular heading stimuli in the coronal (skew) and sagittal (elevation) planes. For visual headings, the bias was much smaller and in the opposite direction such that the vertical component of heading was overestimated. Subjects older than 50 had significantly worse precision and larger biases relative to that of younger subjects for the vestibular conditions, although visual heading estimates were similar. A vector addition model was fit to the data which explains the observed heading biases by the known distribution of otolith organs in humans. The greatly decreased precision with age is explained by the model with decreases in end organ numbers, and relatively greater loss of otoliths that are sensitive to vertical motion. PMID:24249574

Crane, Benjamin T

2014-02-01

392

Horizontal and vertical transport of air over southern Africa  

Microsoft Academic Search

Tropospheric air trajectories that occurred during the Southern African Fire-Atmosphere Research Initiative (SAFARI) in August-October 1992 are described in terms of a circulation classification scheme and the vertical stability of the atmosphere. Three major and frequently occurring stable discontinuities are found to control vertical transport of aerosols in the subtropical atmosphere at the end of the dry season. Of these,

M. Garstang; P. D. Tyson; R. Swap; M. Edwards; P. Kllberg; J. A. Lindesay

1996-01-01

393

Vertical and temporal distribution of two copepod species, Cyclops scutifer  

E-print Network

.J. Flynn Factors structuring zooplankton communities in areas with 24 h of sunlight are not well under- stood. In stratified temperate lakes with fish, zooplankton generally undergo a diel vertical migration. To explore factors that determine vertical structure of zooplankton where DVM does not occur, we obtained

California at Santa Barbara, University of

394

Vertical Integration, Appropriable Rents, and the Competitive Contracting Process  

Microsoft Academic Search

The potential of post-contractural apportunistic behavior for improving market efficiency through intrafirm rather than interfirm transactions is examined under the assumption that vertical costs will increase less than contracting costs as specialized assets and appropriable quasi rents increase. Vertical integration protects against the risk of contract cancellation and can create market power which is not generally referred to as monopoly.

Benjamin Klein; Robert G. Crawford; Armen A. Alchian

1978-01-01

395

The nature and growth of vertical specialization in world trade  

Microsoft Academic Search

Dramatic changes are occurring in the nature of international trade. Production processes increasingly involve a sequential, vertical trading chain stretching across many countries, with each country specializing in particular stages of a good’s production sequence. We document a key aspect of these vertical linkages — the use of imported inputs in producing goods that are exported — which we call

David Hummels; Jun Ishii; Kei-Mu Yi

2001-01-01

396

Segmenting Document Images using Diagonal White Runs and Vertical Edges  

E-print Network

Segmenting Document Images using Diagonal White Runs and Vertical Edges B. Waked, C. Y. Suen and S on diagonal white runs and vertical edges, that divides a document image into columns and blocks which are subsequently classi­ fied as text or graphics. A diagonal white run (drun) is a set of adjacent white pixels

Bergler, Sabine

397

SIMPLE PDF MODELS FOR CONVECTIVELY DRIVEN VERTICAL DIFFUSION  

EPA Science Inventory

The mode of vertical velocity in convective boundary layers is usually negative and the probability distribution function(PDF) of w, pw is rarely symmetrlc. Consequently, vertical diffusion from elevated sources is usually asymmetric and exhibits a descending mode of concentratio...

398

Demonstration of all optical logic gates by single\\/differential typed vertical cavity laser with depleted optical thyristor  

Microsoft Academic Search

Latching optical switches and optical logic gates with AND or OR, plus the INVERT functionality are demonstrated for the first time by the monolithic integration of a single and differential typed vertical cavity lasers with depleted optical thyristor (VCL-DOT) structure with a low threshold current of 0.65 mA, a high on\\/off contrast ratio of more than 50 dB, a high

Woon-Kyung Choi; Doo-Gun Kim; Yon-Tae Moon; Do-Gyun Kim; Hoseong Kim; Tae Kyung Chung; Young-Wan Choi; Kent D. Choquette; Seok Lee; Deok-Ha Woo

2007-01-01

399

An efficient moderate-size vertical-incidence ionosonde antenna for 2-20MHz polarization studies  

Microsoft Academic Search

A wide cone-angle conical spiral antenna which has been developed for use as a circularly polarized vertical-incidence ionosonde antenna is described. It exhibits an 80-degree beamwidth, 5-dB gain, axial ratio of 1.2:1 and SWR less than 2:1 typically over the band 2-20 MHz. The entire structure is only 38 meters high and 52 meters in diameter. Extensive measurements on models

F. Dietrich; R. Long

1969-01-01

400

Crustal noble gases in deep brines as natural tracers of vertical transport processes in the Michigan Basin  

Microsoft Academic Search

Noble gas concentrations and isotopic ratios are presented for 38 deep (?0.5–3.6 km) brine samples in the Michigan Basin. These brine samples clearly show the presence of an important crustal component of 4He, 21Ne, 40Ar, and 136Xe. Both 40Arcrust and 136Xecrust display the presence of a strong vertical gradient along the sedimentary strata of the basin. We show that the

Lin Ma; Maria Clara Castro; Chris M. Hall

2009-01-01

401

Thorium234 as a tracer of spatial, temporal and vertical variability in particle flux in the North Pacific  

Microsoft Academic Search

An extensive 234Th data set was collected at two sites in the North Pacific: ALOHA, an oligotrophic site near Hawaii, and K2, a mesotrophic HNLC site in the NW Pacific as part of the VERTIGO (VERtical Transport In the Global Ocean) study. Total 234Th:238U activity ratios near 1.0 indicated low particle fluxes at ALOHA, while 234Th:238U ?0.6 in the euphotic

K. O. Buesseler; S. Pike; K. Maiti; C. H. Lamborg; D. A. Siegel; T. W. Trull

2009-01-01

402

Using 234Th disequilibria to estimate the vertical removal rates of polycyclic aromatic hydrocarbons from the surface ocean  

Microsoft Academic Search

A novel 234Th-coupled approach was employed to deduce the vertical fluxes of polycyclic aromatic hydrocarbons (PAHs) through surface waters of harbor, coastal, shelf, and pelagic regimes. We found reasonable agreement between these surface ocean fluxes, based on direct measurements of mixed-layer properties, and fluxes deduced from underlying sediments. Fluxes decreased exponentially away from the northeastern U.S.A. Source-diagnostic molecular ratios indicate

Örjan Gustafsson; Philip M. Gschwend; Ken O. Buesseler

1997-01-01

403

Crustal noble gases in deep brines as natural tracers of vertical transport processes in the Michigan Basin  

Microsoft Academic Search

Noble gas concentrations and isotopic ratios are presented for 38 deep (˜0.5-3.6 km) brine samples in the Michigan Basin. These brine samples clearly show the presence of an important crustal component of 4He, 21Ne, 40Ar, and 136Xe. Both 40Arcrust and 136Xecrust display the presence of a strong vertical gradient along the sedimentary strata of the basin. We show that the

Lin Ma; Maria Clara Castro; Chris M. Hall

2009-01-01

404

Properties of vertically self-gravitating accretion discs with a dissipative corona  

E-print Network

The steady-state structure of a disc with a corona is analyzed when the vertical component of the gravitational force due to the self-gravity of the disc is considered. For the energy exchange between the disc and the corona, we assume a fraction f of the dissipated energy inside the accretion disc is transported to the corona via the magnetic tubes. Analytical solutions corresponding to a prescription for f (in which this parameter directly depends on the ratio of the gas pressure to the total pressure) or free f are presented and their physical properties are studied in detail. We show that the existence of the corona not only decreases the temperature of the disc, but also increases the surface density.The vertical component of the gravitational force due to the self-gravity of the disc decreases the self-gravitating radius and the mass of the fragments at this radius. However, as more energy is transported from the disc to the corona, the effect of the vertical component of the gravitational force due to the self-gravity of the disc on the self-gravitating radius becomes weaker, though the mass of the fragments is reduced irrespective of the amount of the energy exchange from the disc to the corona.

Fazeleh Khajenabi; Peter Duffy

2008-05-30

405

Efficiency improvement of a vertical light-emitting diode through surface plasmon coupling and grating scattering.  

PubMed

The enhancement of output intensity, the generation of polarized output, and the reduction of the efficiency droop effect in a surface plasmon (SP) coupled vertical light-emitting diode (LED) with an Ag nano-grating structure located between the p-GaN layer and the wafer bonding metal for inducing SP coupling with the InGaN/GaN quantum wells (QWs) are demonstrated. In fabricating the vertical LED, the patterned sapphire substrate is removed with a photoelectrochemical liftoff technique. Based on the reflection measurement from the metal grating structure and the numerical simulation result, it is found that the localized surface plasmon (LSP) resonance induced around the metal grating crest plays the major role in the SP-QW coupling process although a hybrid mode of LSP and surface plasmon polariton can be generated in the coupling process. By adding a surface grating structure to the SP-coupled vertical LED on the n-GaN side, the output intensity is further enhanced, the output polarization ratio is further increased, and the efficiency droop effect is further suppressed. PMID:24922391

Lin, Chun-Han; Hsieh, Chieh; Tu, Charng-Gan; Kuo, Yang; Chen, Horng-Shyang; Shih, Pei-Ying; Liao, Che-Hao; Kiang, Yean-Woei; Yang, C C; Lai, Chih-Han; He, Guan-Ru; Yeh, Jui-Hung; Hsu, Ta-Cheng

2014-05-01

406

Vertical Profile of Aerosol Radiative Effects over Asia Estimated from CALIPSO Data  

NASA Astrophysics Data System (ADS)

Asian atmosphere is heavily loaded with aerosol particles. Continuous emissions of either natural desert dust or anthropogenic urban and/or biomass burning aerosols in Asia cause considerable changes in the radiative properties of aerosols which are a focus of many current global climate change models due to their significant effects on the perturbation of the radiation budget and cloud microphysical properties. Present study investigates vertical profiles of aerosols radiative effects over this region using CALIPSO. Vertical distribution of aerosol extinction coefficients at 532 nm and 1064 nm, angstrom exponent derived from these two extinction coefficients, and depolarization ratio at 532 nm have been included to determine different types of aerosols, especially dust, sea salt and anthropogenic aerosols like soot. Special importance has been given to investigate the radiative effects over source and downwind regions. This study presents that high-altitude aerosols in between four to eight kilometer altitude carry a significant role, especially for dust aerosols which dominate over the source regions as well as the downwind regions where they mix with pollutants. These high-altitude dust aerosols exert stronger radiative heating when mixed with soot over the downwind regions than those freshly generated over the source regions. The vertical distribution of aerosol radiative heating rate over Asia and the changes in heating profiles for different types of dust over source as well as downwind regions will be presented.

Das, S. K.; Chen, J.

2013-12-01

407

A vertical handoff decision algorithm based on ARMA prediction model  

NASA Astrophysics Data System (ADS)

With the development of computer technology and the increasing demand for mobile communications, the next generation wireless networks will be composed of various wireless networks (e.g., WiMAX and WiFi). Vertical handoff is a key technology of next generation wireless networks. During the vertical handoff procedure, handoff decision is a crucial issue for an efficient mobility. Based on auto regression moving average (ARMA) prediction model, we propose a vertical handoff decision algorithm, which aims to improve the performance of vertical handoff and avoid unnecessary handoff. Based on the current received signal strength (RSS) and the previous RSS, the proposed approach adopt ARMA model to predict the next RSS. And then according to the predicted RSS to determine whether trigger the link layer triggering event and complete vertical handoff. The simulation results indicate that the proposed algorithm outperforms the RSS-based scheme with a threshold in the performance of handoff and the number of handoff.

Li, Ru; Shen, Jiao; Chen, Jun; Liu, Qiuhuan

2011-12-01

408

A vertical handoff decision algorithm based on ARMA prediction model  

NASA Astrophysics Data System (ADS)

With the development of computer technology and the increasing demand for mobile communications, the next generation wireless networks will be composed of various wireless networks (e.g., WiMAX and WiFi). Vertical handoff is a key technology of next generation wireless networks. During the vertical handoff procedure, handoff decision is a crucial issue for an efficient mobility. Based on auto regression moving average (ARMA) prediction model, we propose a vertical handoff decision algorithm, which aims to improve the performance of vertical handoff and avoid unnecessary handoff. Based on the current received signal strength (RSS) and the previous RSS, the proposed approach adopt ARMA model to predict the next RSS. And then according to the predicted RSS to determine whether trigger the link layer triggering event and complete vertical handoff. The simulation results indicate that the proposed algorithm outperforms the RSS-based scheme with a threshold in the performance of handoff and the number of handoff.

Li, Ru; Shen, Jiao; Chen, Jun; Liu, Qiuhuan

2012-01-01

409

Steerable vertical to horizontal energy transducer for mobile robots  

DOEpatents

The present invention provides a steerable vertical to horizontal energy transducer for mobile robots that less complex and requires less power than two degree of freedom tilt mechanisms. The present invention comprises an end effector that, when mounted with a hopping actuator, translates along axis (typically vertical) actuation into combined vertical and horizontal motion. The end effector, or foot, mounts with an end of the actuator that moves toward the support surface (typically a floor or the earth). The foot is shaped so that the first contact with the support surface is off the axis of the actuator. Off-axis contact with the support surface generates an on-axis force (typically resulting in vertical motion) and a moment orthogonal to the axis. The moment initiates a horizontal tumbling motion, and tilts the actuator so that its axis is oriented with a horizontal component and continued actuation generates both vertical and horizontal force.

Spletzer, Barry L. (Albuquerque, NM); Fischer, Gary J. (Albuquerque, NM); Feddema, John T. (Albuquerque, NM)

2001-01-01

410

Modeling and optimization of atomic layer deposition processes on vertically aligned carbon nanotubes.  

PubMed

Many energy conversion and storage devices exploit structured ceramics with large interfacial surface areas. Vertically aligned carbon nanotube (VACNT) arrays have emerged as possible scaffolds to support large surface area ceramic layers. However, obtaining conformal and uniform coatings of ceramics on structures with high aspect ratio morphologies is non-trivial, even with atomic layer deposition (ALD). Here we implement a diffusion model to investigate the effect of the ALD parameters on coating kinetics and use it to develop a guideline for achieving conformal and uniform thickness coatings throughout the depth of ultra-high aspect ratio structures. We validate the model predictions with experimental data from ALD coatings of VACNT arrays. However, the approach can be applied to predict film conformality as a function of depth for any porous topology, including nanopores and nanowire arrays. PMID:24778944

Yazdani, Nuri; Chawla, Vipin; Edwards, Eve; Wood, Vanessa; Park, Hyung Gyu; Utke, Ivo

2014-01-01

411

Measurement of D-Meson Branching Ratios.  

National Technical Information Service (NTIS)

Charm data from 360 GeV/c (pi-)p interactions are used to give results on D-meson branching ratios. The analysis is based on 114 charm events containing 183 observed charm particle decays. The authors present topological branching ratios and decay multipl...

M. Aguilar-Benitez, W. W. M. Allison, J. F. Baland, W. Bartl, V. M. Begalli

1985-01-01

412

CCSSM Challenge: Graphing Ratio and Proportion  

ERIC Educational Resources Information Center

A renewed emphasis was placed on ratio and proportional reasoning in the middle grades in the Common Core State Standards for Mathematics (CCSSM). The expectation for students includes the ability to not only compute and then compare and interpret the results of computations in context but also interpret ratios and proportions as they are…

Kastberg, Signe E.; D'Ambrosio, Beatriz S.; Lynch-Davis, Kathleen; Mintos, Alexia; Krawczyk, Kathryn

2013-01-01

413

Losing money with a high Sharpe ratio  

Microsoft Academic Search

A simple example shows that losing all money is compatible with a very high Sharpe ratio (as computed after losing all money). However, the only way that the Sharpe ratio can be high while losing money is that there is a period in which all or almost all money is lost. This note explores the best achievable Sharpe and Sortino

Vladimir Vovk

2011-01-01

414

Ratio Rule Mining from Multiple Data Sources  

Microsoft Academic Search

Both multiple source data mining and streaming data mining problems have attracted much attention in the past decade. In contrast to traditional association-rule mining, to capture the quantitative association knowledge, a new paradigm called Ratio Rule (RR) was proposed recently. We extend this framework to mining ratio rules from multiple source data streams which is a novel and challenging problem.

Jun Yan; Qiang Yang; Benyu Zhang; Qiansheng Cheng; Zheng Chen

415

Calculating Obscuration Ratios Of Contaminated Surfaces  

NASA Technical Reports Server (NTRS)

Equations derived to estimate obscuration ratios of surfaces contaminated by particles. Ratio is fraction of surface area covered by particles. Useful as index of cleanliness in clean-room operations in manufacturing of semiconductor devices, magnetic recording media, optical devices, and pharmaceutical and biotechnological products.

Barengoltz, Jack B.

1989-01-01

416

The Divine Ratio and Golden Rectangles.  

ERIC Educational Resources Information Center

The material examines aspects of Fibonacci and Lucas sequences, the generation of the Divine Ratio, and the nature of this ratio in golden rectangles, triangles, and figures made up of golden triangles. It is noted Lucas sequence is formed like Fibonacci but has one and three as the first elements. (Author/MP)

Cooper, Martin

1982-01-01

417

Is that really your Strehl ratio?  

Microsoft Academic Search

Strehl ratio is the most commonly used metric for adaptive optics (AO) performance. It is also the most misused metric. Every Strehl ratio measurement algorithm has subtle differences that result in different measured values. This creates problems when comparing different measurements of the same AO system and even more problems when trying to compare results from different systems. To determine

Lewis C. Roberts Jr.; Marshall D. Perrin; Franck Marchis; Anand Sivaramakrishnan; Russell B. Makidon; Julian C. Christou; Bruce A. Macintosh; Lisa A. Poyneer; Marcos A. van Dam; Mitchell Troy

2004-01-01

418

Economy Track: Employment to Population Ratio  

NSDL National Science Digital Library

Time plot compares the employment-population ratio - the broadest measure of people who are working in America. Allows to compare between recessions, also allows to compare between demographic groups -- by sex, race/ethnicity and educational attainment. Also shows the secular trend for employment-population ratio since 1973.

Institute, Economic P.

419

Graphene vertical hot-electron terahertz detectors  

NASA Astrophysics Data System (ADS)

We propose and analyze the concept of the vertical hot-electron terahertz (THz) graphene-layer detectors (GLDs) based on the double-GL and multiple-GL structures with the barrier layers made of materials with a moderate conduction band off-set (such as tungsten disulfide and related materials). The operation of these detectors is enabled by the thermionic emissions from the GLs enhanced by the electrons heated by incoming THz radiation. Hence, these detectors are the hot-electron bolometric detectors. The electron heating is primarily associated with the intraband absorption (the Drude absorption). In the frame of the developed model, we calculate the responsivity and detectivity as functions of the photon energy, GL doping, and the applied voltage for the GLDs with different number of GLs. The detectors based on the cascade multiple-GL structures can exhibit a substantial photoelectric gain resulting in the elevated responsivity and detectivity. The advantages of the THz detectors under consideration are associated with their high sensitivity to the normal incident radiation and efficient operation at room temperature at the low end of the THz frequency range. Such GLDs with a metal grating, supporting the excitation of plasma oscillations in the GL-structures by the incident THz radiation, can exhibit a strong resonant response at the frequencies of several THz (in the range, where the operation of the conventional detectors based on A3B5 materials, in particular, THz quantum-well detectors, is hindered due to a strong optical phonon radiation absorption in such materials). We also evaluate the characteristics of GLDs in the mid- and far-infrared ranges where the electron heating is due to the interband absorption in GLs.

Ryzhii, V.; Satou, A.; Otsuji, T.; Ryzhii, M.; Mitin, V.; Shur, M. S.

2014-09-01

420

Spirit Near 'Stapledon' on Sol 1802 (Vertical)  

NASA Technical Reports Server (NTRS)

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.

2009-01-01

421

Scavenging ratios based on inflow air concentrations  

SciTech Connect

Scavenging ratios were calculated from field measurements made during April 1985. Event precipitation samples were collected at the surface, but air chemistry measurements in the air mass feeding the precipitation were made from an aircraft. In contrast, ratios calculated in previous studies have used air concentration and precipitation chemistry data from only surface measurements. Average scavenging ratios were calculated for SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +}, total sulfate, total nitrate, and total ammonium for 5 events; the geometric mean of these scavenging ratios were 8.5 {times} 10{sup 5}, 5.6 {times} 10{sup 6}, 4.3 {times} 10{sup 5}, 3.4 {times} 10{sup 5}, 2.4 {times} 10{sup 6}, and 9.7 {times} 10{sup 4}, respectively. These means are similar to but less variable than previous ratios formed using only surface data.

Davis, W.E.; Dana, M.T.; Lee, R.N.; Slinn, W.G.N.; Thorp, J.M.

1991-07-01

422

Duty ratio of cooperative molecular motors  

NASA Astrophysics Data System (ADS)

Molecular motors are found throughout the cells of the human body and have many different and important roles. These micromachines move along filament tracks and have the ability to convert chemical energy into mechanical work that powers cellular motility. Different types of motors are characterized by different duty ratios, which is the fraction of time that a motor is attached to its filament. In the case of myosin II (a nonprocessive molecular machine with a low duty ratio), cooperativity between several motors is essential to induce motion along its actin filament track. In this work we use statistical mechanical tools to calculate the duty ratio of cooperative molecular motors. The model suggests that the effective duty ratio of nonprocessive motors that work in cooperation is lower than the duty ratio of the individual motors. The origin of this effect is the elastic tension that develops in the filament which is relieved when motors detach from the track.

Dharan, Nadiv; Farago, Oded

2012-02-01

423

High Transformer ratios in collinear wakefield accelerators.  

SciTech Connect

Based on our previous experiment that successfully demonstrated wakefield transformer ratio enhancement in a 13.625 GHz dielectric-loaded collinear wakefield accelerator using the ramped bunch train technique, we present here a redesigned experimental scheme for even higher enhancement of the efficiency of this accelerator. Design of a collinear wakefield device with a transformer ratio R2, is presented. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2. To match the wavelength of the fundamental mode of the wakefield with the bunch length (sigmaz=2 mm) of the new Argonne wakefield accelerator (AWA) drive gun (where the experiment will be performed), a 26.625 GHz dielectric based accelerating structure is required. This transformer ratio enhancement technique based on our dielectric-loaded waveguide design will result in a compact, high efficiency accelerating structures for future wakefield accelerators.

Power, J. G.; Conde, M.; Yusof, Z.; Gai, W.; Jing, C.; Kanreykin, A.; Schoessow, P.; High Energy Physics; Euclid Techlabs, LLC

2008-01-01

424

Stereoscopic Analysis of Optic Nerve Head Parameters in Primary Open Angle Glaucoma: The Glaucoma Stereo Analysis Study  

PubMed Central

Purpose The Glaucoma Stereo Analysis Study (GSAS), a cross sectional multicenter collaborative study, used a stereo fundus camera to assess various morphological parameters of the optic nerve head (ONH) in glaucoma patients and investigated the relationships between these parameters and patient characteristics. Subjects and Methods The study included 187 eyes of 187 subjects with primary open angle glaucoma or normal tension glaucoma (male: female ?=?100: 87, age ?=?61±9 years). Stereo pairs of ONH photographs were made with a stereo fundus camera (nonmyd WX). ONH morphological parameters were calculated with prototype analysis software. In addition to 35 standard parameters, we defined three novel parameters: disc tilt angle, rim decentering, and the absolute value of rim decentering. The correlation between each parameter and patient characteristics was analyzed with Spearman's rank correlation coefficient. Results Patient characteristics included refractive error of ?3.38±3.75 diopters, intraocular pressure (IOP) of 13.6±2.6 mmHg, and visual field mean deviation (MD) of ?4.71±3.26 dB. Representative ONH parameters included a horizontal disc width of 1.66±0.28 mm, vertical disc width of 1.86±0.23 mm, disc area of 2.42±0.63 mm2, cup area of 1.45±0.57 mm2, and cup volume of 0.31±0.22 mm3. Correlation analysis revealed significant negative associations between vertical cup-to-disc ratio (0.82±0.08) and MD (r?=??0.40, P<0.01) and between disc tilt angle (10.5±12.5 degrees) and refractive error (r?=??0.36, P<0.01). Seventy-five percent of the eyes had a positive value for rim decentering (0.30±0.42), indicating that rim thinning manifested more often as an inferior lesion than a superior lesion. Conclusion We used stereoscopic analysis to establish a database of ONH parameters, which may facilitate future studies of glaucomatous changes in ONH morphology. PMID:24922327

Yokoyama, Yu; Tanito, Masaki; Nitta, Koji; Katai, Maki; Kitaoka, Yasushi; Omodaka, Kazuko; Tsuda, Satoru; Nakagawa, Toshiaki; Nakazawa, Toru

2014-01-01

425

Constraints on aerosol processes in climate models from vertically-resolved aircraft observations of black carbon  

NASA Astrophysics Data System (ADS)

Evaluation of the aerosol schemes in current climate models is dependent upon the available observational data. In-situ observations from flight campaigns can provide valuable data about the vertical distribution of aerosol that is difficult to obtain from satellite or ground-based platforms, although they are localised in space and time. Using single-particle soot-photometer (SP2) measurements from the HIAPER Pole-to-Pole Observations (HIPPO) campaign, which consists of many vertical profiles over a large region of the Pacific, we evaluate the meridional and vertical distribution of black carbon (BC) aerosol simulated by the HadGEM3-UKCA and ECHAM5-HAM2 models. Both models show a similar pattern of overestimating the BC column burden compared to that derived from the observations, in many areas by an order of magnitude. However, by sampling the simulated BC mass mixing ratio along the flight track and comparing to the observations, we show that this discrepancy has a rather different vertical structure in the two models: in HadGEM3-UKCA the discrepancy is dominated by excess aerosol in the tropical upper troposphere, while in ECHAM5-HAM2 areas of discrepancy are spread across many different latitudes and altitudes. Using this methodology, we conduct sensitivity tests on two specific elements of the models: biomass-burning emissions and scavenging by convective precipitation. We show that, by coupling the convective scavenging more tightly with convective transport, both the column burden and vertical distribution of BC in HadGEM3-UKCA are much improved with respect to the observations, with a substantial and statistically significant increase in correlation - this demonstrates the importance of a realistic representation of this process. In contrast, updating from GFED2 to GFED3.1 biomass-burning emissions makes a more modest improvement in both models, which is not statistically significant. By comparing our results with a more traditional approach using regional- and monthly-mean vertical profile curves, we show that the point-by-point analysis allows the model improvements to be demonstrated more clearly. We also demonstrate the important role that nudged simulations (where the large-scale model dynamics are continuously relaxed towards a reanalysis) can play in this type of evaluation, allowing statistically significant differences between configurations of the aerosol scheme to be seen where the differences between the corresponding free-running simulations would not be significant.

Kipling, Z.; Stier, P.; Schwarz, J. P.; Perring, A. E.; Spackman, J. R.; Mann, G. W.; Johnson, C. E.; Telford, P. J.

2013-06-01

426

Longitudinal Differences of Ionospheric Vertical Density Distribution and Equatorial Electrodynamics  

NASA Technical Reports Server (NTRS)

Accurate estimation of global vertical distribution of ionospheric and plasmaspheric density as a function of local time, season, and magnetic activity is required to improve the operation of space-based navigation and communication systems. The vertical density distribution, especially at low and equatorial latitudes, is governed by the equatorial electrodynamics that produces a vertical driving force. The vertical structure of the equatorial density distribution can be observed by using tomographic reconstruction techniques on ground-based global positioning system (GPS) total electron content (TEC). Similarly, the vertical drift, which is one of the driving mechanisms that govern equatorial electrodynamics and strongly affect the structure and dynamics of the ionosphere in the low/midlatitude region, can be estimated using ground magnetometer observations. We present tomographically reconstructed density distribution and the corresponding vertical drifts at two different longitudes: the East African and west South American sectors. Chains of GPS stations in the east African and west South American longitudinal sectors, covering the equatorial anomaly region of meridian approx. 37 deg and 290 deg E, respectively, are used to reconstruct the vertical density distribution. Similarly, magnetometer sites of African Meridian B-field Education and Research (AMBER) and INTERMAGNET for the east African sector and South American Meridional B-field Array (SAMBA) and Low Latitude Ionospheric Sensor Network (LISN) are used to estimate the vertical drift velocity at two distinct longitudes. The comparison between the reconstructed and Jicamarca Incoherent Scatter Radar (ISR) measured density profiles shows excellent agreement, demonstrating the usefulness of tomographic reconstruction technique in providing the vertical density distribution at different longitudes. Similarly, the comparison between magnetometer estimated vertical drift and other independent drift observation, such as from VEFI onboard Communication/Navigation Outage Forecasting System (C/NOFS) satellite and JULIA radar, is equally promising. The observations at different longitudes suggest that the vertical drift velocities and the vertical density distribution have significant longitudinal differences; especially the equatorial anomaly peaks expand to higher latitudes more in American sector than the African sector, indicating that the vertical drift in the American sector is stronger than the African sector.

Yizengaw, E.; Zesta, E.; Moldwin, M. B.; Damtie, B.; Mebrahtu, A.; Valledares, C.E.; Pfaff, R. F.

2012-01-01

427

The use of slug tests to describe vertical variations in hydraulic conductivity  

USGS Publications Warehouse

Multilevel slug tests provide one means of obtaining estimates of hydraulic conductivity on a scale of relevance for contaminant transport investigations. A numerical model is employed here to assess the potential of multilevel slug tests to provide information about vertical variations in hydraulic conductivity under conditions commonly faced in field settings. The results of the numerical simulations raise several important issues concerning the effectiveness of this technique. If the length of the test interval is of the order of the average layer thickness, considerable error may be introduced into the conductivity estimates owing to the effects of adjoining layers. The influence of adjoining layers is dependent on the aspect ratio (length of test interval/well radius) of the tesy interval and the flow properties of the individual layers. If a low-permeability skin is present at the well, the measured vertical variations will be much less than the actual variations, owing to the influence of the skin conductivity on the parameter estimates. A high-permeability skin can also produce apparent vertical variations that are much less than the actual, owing to water flowing vertically along the conductive skin. In cases where the test interval spans a number of layers, a slug test will yield an approximate thickness-weighted average of the hydraulic conductivities of the intersected layers. In most cases, packer circumvention should not be a major concern when packers of 0.75 m or longer are employed. Results of this study are substantiated by recently reported field tests that demonstrate the importance of well emplacement and development activities for obtaining meaningful estimates from a program of multilevel slug tests. ?? 1994.

Butler, Jr. , J. J.; Bohling, G. C.; Hyder, Z.; McElwee, C. D.

1994-01-01

428

Flocculation and phytoplankton cell size can alter 234Th-based estimates of the vertical flux of particulate organic carbon in the sea  

Microsoft Academic Search

The deficit of 234Th relative to its radioactive parent 238U in the surface ocean can yield reliable estimates of vertical Particulate Organic Carbon (POC) fluxes to deeper waters, but only when coupled with an accurate ratio of POC concentration to activity of 234Th on sinking matter. Assuming a simple partitioning of suspended phytoplankton mass between single cells and flocs, we

Anya M. Waite; Paul S. Hill

2006-01-01

429

Modeling and experimental study of nucleate boiling on a vertical array of horizontal plain tubes  

SciTech Connect

An investigation of nucleate boiling on a vertical array of horizontal plain tubes is presented in this paper. Experiments were performed with refrigerant R123 at reduced pressures varying from 0.022 to 0.64, tube pitch to diameter ratios of 1.32, 1.53 and 2.00, and heat fluxes from 0.5 to 40 kW/m{sup 2}. Brass tubes with external diameters of 19.05 mm and average roughness of 0.12 {mu}m were used in the experiments. The effect of the tube spacing on the local heat transfer coefficient along the tube array was negligible within the present range of experimental conditions. For partial nucleate boiling, characterized by low heat fluxes, and low reduced pressures, the tube positioning shows a remarkable effect on the heat transfer coefficient. Based on these data, a general correlation for the prediction of the nucleate boiling heat transfer coefficient on a vertical array of horizontal tubes under flooded conditions was proposed. According to this correlation, the ratio between the heat transfer coefficients of a given tube and the lowest tube in the array depends only on the tube row number, the reduced pressure and the heat flux. By using the proposed correlation, most of the experimental heat transfer coefficients obtained in the present study were predicted within {+-}15%. The new correlation compares reasonably well with independent data from the literature. (author)

Ribatski, Gherhardt [Department of Mechanical Engineering, Escola de Engenharia de Sao Carlos (EESC), University of Sao Paulo (USP), Av. Trabalhador SanCarlense 400, Centro, Sao Carlos, SP (Brazil); Saiz Jabardo, Jose M. [Escola Politecnica Superior, Universidade da Coruna, Mendizabal s/n Esteiro, 15403 Ferrol, Coruna (Spain); da Silva, Evandro Fockink [Centro Federal de Educacao Tecnologica de Minas Gerais - CEFETMG, Unidade Divinopolis, R. Monte Santo, 319, Divinopolis, MG (Brazil)

2008-09-15

430

VERTICAL BEAM SIZE CONTROL IN TLS AND TPS.  

SciTech Connect

Vertical beam size control is an important issue in the light source operations. The horizontal-vertical betatron coupling and vertical dispersion were measured and corrected to small values in the TLS 1.5 GeV storage ring. Estimated beam sizes are compared with the measured values. By employing an effective transverse damping system, the vertical beam blow-up due to transverse coherent instabilities, such as the fast-ion beam instability, was suppressed. As a result, the light source is very stable. In NSRRC we are designing an ultra low emittance 3-GeV storage ring and its designed vertical beam size could be as small as a few microns. The ground and mechanic vibration effects, and coherent instabilities could spoil the expected photon brightness due to blow-up of the vertical beam size if not well taken care of. The contributions of these effects to vertical beam size increase will be evaluated and the counter measures to minimize them will be proposed and reported in this paper.

KUO, C.C.; CHEN, J.R.; CHOU, P.J.; CHANG, H.P.; HSU, K.T.; LUO, G.H.; TSAI, H.J.; WANG, D.J.; WANG, M.H.

2006-06-26

431

Helium isotope ratios in Ethiopian Rift basalts  

NASA Astrophysics Data System (ADS)

Helium isotope ratios were measured in olivine and pyroxene phenocrysts from basalts of the Ethiopian Rift Valley and Afar Depression between 6° and 15°N and 37° and 43°E. 3He/ 4He ratios range from 6 to 17 times the atmospheric value (R A = 1.4 × 10 -6), that is, from ratios less than typical MORB (depleted mantle) helium (R/R A= 8 ± 1) to ratios similar to high- 3He hotspots and to the Yellowstone hotspot (R/R A= 16.5). The high 3He/ 4He ratios occur all along the Ethiopian Rift and well up into the Afar Depression, with a maximum value of 17.0 R A at 8°N in the Rift Axis and a high value of 14.2 R A in the central Tat'Ali sector of the Afar Depression. The ratios decrease to MORB-like values near the edge of the Red Sea, and to sub-MORB ratios (5-6 R A) at the northern end of the Rift (Zula Peninsula) and at the southern end, at lakes Abaya and Chamo. The Ethiopian Rift provides the only continental hotspot terrain in which helium isotope ratios can be compared in detail between volcanic lavas and associated geothermal and volcanic gases, a primary motivation for this work. Comparison with our previously measured ratios in fluids and gases (range 2-15 R A) shows excellent agreement in the areas sampled for both lavas and fluids, and indicates that high-temperature volcanic fluids can be used for establishing helium isotope signatures in such terrains. The high- 3He values in both fluids and basalts show that a Primitive Mantle (PM) component is required and that a Lower Mantle High- 3He plume is strongly involved as a driving force in the rifting process of the East African Rift System.

Scarsi, P.; Craig, H.

1996-11-01

432

TIGHT ASPECT RATIO TOKAMAKS - THEORY AND EXPERIMENT  

SciTech Connect

The START (Small Tight Aspect Ratio Tokamak) experiment became operational in January 1991 at AEA Fusion Culham Laboratory. It is the only tokamak producing hot plasmas at aspect ratios as low as A = R/a approximately 1.3, and is providing valuable insight into the physical processes (such as toroidicity and trapping) involved at low aspect ratio. Three topics are discussed in this paper: equilibrium properties, including evidence of neo-classical and bootstrap effects; energy confinement studies; and MHD properties, including possible explanations for the apparent absence of the major disruption at low A.

Sykes, A [Culham Centre for Fusion Energy, Culham, UK; Peng, Yueng Kay Martin [ORNL

1993-01-01

433

Optimal sampling ratios in comparative diagnostic trials  

PubMed Central

Summary A subjective sampling ratio between the case and the control groups is not always an efficient choice to maximize the power or to minimize the total required sample size in comparative diagnostic trials.We derive explicit expressions for an optimal sampling ratio based on a common variance structure shared by several existing summary statistics of the receiver operating characteristic curve. We propose a two-stage procedure to estimate adaptively the optimal ratio without pilot data. We investigate the properties of the proposed method through theoretical proofs, extensive simulation studies and a real example in cancer diagnostic studies. PMID:24948841

Dong, Ting; Tang, Liansheng Larry; Rosenberger, William F.

2014-01-01

434

Static Footprint Local Forces, Areas, and Aspect Ratios for Three Type 7 Aircraft Tires  

NASA Technical Reports Server (NTRS)

The National Tire Modeling Program (NTMP) is a joint NASA/industry effort to improve the understanding of tire mechanics and develop accurate analytical design tools. This effort includes fundamental analytical and experimental research on the structural mechanics of tires. Footprint local forces, areas, and aspect ratios were measured. Local footprint forces in the vertical, lateral, and drag directions were measured with a special footprint force transducer. Measurements of the local forces in the footprint were obtained by positioning the transducer at specified locations within the footprint and externally loading the tires. Three tires were tested: (1) one representative of those used on the main landing gear of B-737 and DC-9 commercial transport airplanes, (2) a nose landing gear tire for the Space Shuttle Orbiter, and (3) a main landing gear tire for the Space Shuttle Orbiter. Data obtained for various inflation pressures and vertical loads are presented for two aircraft tires. The results are presented in graphical and tabulated forms.

Howell, William E.; Perez, Sharon E.; Vogler, William A.

1991-01-01

435

Vertical lid split approach for optic nerve sheath decompression  

PubMed Central

We describe a vertical lid split orbitotomy approach to perform optic nerve sheath fenestration which was done in a patient with idiopathic intracranial hypertension. A vertical lid split incision was used to enter the superomedial orbit and approach the optic nerve sheath. This approach resulted in a successful nerve sheath fenestration, with improvement in the patient's symptoms. The vertical lid split incision provides access to the optic nerve sheath with minimal morbidity and may be an option for optic nerve sheath decompression. PMID:19574700

Prabhakaran, Venkatesh C; Selva, Dinesh

2009-01-01

436

Sidewall containment of liquid metal with vertical alternating magnetic fields  

DOEpatents

An apparatus for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent to the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel. 8 figs.

Lari, R.J.; Praeg, W.F.; Turner, L.R.; Battles, J.E.; Hull, J.R.; Rote, D.M.

1988-06-17

437

Fabrication of micro-pin array with high aspect ratio on stainless steel using nanosecond laser beam machining  

NASA Astrophysics Data System (ADS)

In this paper, a micro-pin array with a high aspect ratio was fabricated on AISI 304 using laser beam ablation for attachment to a vertical wall. In recent times, there has been research in various fields, including robotics and bio-MEMS, regarding attachment to vertical walls, and micro-pin arrays may offer the best solution. For vertical wall attachment, the micro-pin should have a high aspect ratio, long length, and sharp tip. The recast layer could be piled due to the chromium oxide with high surface tension and viscosity of chromium oxide, and it composed the micro-pins with high aspect ratio. X-ray photoelectron spectroscopy (XPS) was used to identify the characteristics of the piled recast layer. The machining characteristics for a high aspect ratio micro-pin array were investigated according to laser beam machining parameters. In addition, experiments for attaching force relative to the surface roughness of the subject plane were carried out.

Lee, Se Won; Shin, Hong Shik; Chu, Chong Nam

2013-01-01

438

A new vertical MOSFET ``Vertical Logic Circuit (VLC) MOSFET'' suppressing asymmetric characteristics and realizing an ultra compact and robust logic circuit  

NASA Astrophysics Data System (ADS)

The asymmetric characteristics of the conventional vertical MOSFET are examined. To reduce the IR drop influences of the diffusion resistance for the vertical MOSFET, a new vertical MOSFET for the Vertical Logic Circuit (VLC) configuration, which separates the current paths of small currents from large currents, has been proposed.

Sakui, Koji; Endoh, Tetsuo

2010-11-01

439

Reduction ratio control for continuously variable transmission  

SciTech Connect

This patent describes a reduction ratio control for a continuously variable transmission of a motor vehicle, the continuously variable transmission being connected to an engine of the motor vehicle to be driven thereby, the reduction ratio control comprising: means for carrying out a reduction ratio change of the continuously variable transmission in such a manner as to decrease a difference between an actual value in a predetermined operating variable and a target value in the predetermined operating variable toward zero; means for determining a deceleration which the motor vehicle is subject to; means for changing the target value to a new target value in response to the deceleration after the deceleration which the motor vehicle is subjected to is determined; and the means for carrying out the reduction ratio change causes the actual value to approach the new target value quicker than it controlled the actual value to approach the target value.

Kumura, H.

1989-06-06

440

Detrended minimum-variance hedge ratio: A new method for hedge ratio at different time scales  

NASA Astrophysics Data System (ADS)

In this paper, based on the detrended fluctuation analysis (DFA) method and the detrended cross-correlation analysis (DCCA) method, we propose an improved method of minimum-variance (MV) hedge ratio, i.e., the detrended minimum-variance (D-MV) hedge ratio, which can measure the hedge ratio at different time scales. The proposed D-MV hedge ratio is defined as the detrended covariance function between spot and futures returns divided by the detrended variance function of futures returns. Through the simulated and empirical analysis, we find that (i) the outcomes of the hedge ratio and the corresponding hedging effectiveness for the D-MV hedge ratio are diverse at different time scales, which can meet needs of various hedging participants with different hedging horizons; (ii) our proposed D-MV hedge ratio has a better hedging performance and a greater potential to determine the hedge ratio because its results of hedging effectiveness at most of time scales are better than those of the traditional MV hedge ratio; and (iii) as for the method of D-MV hedge ratio for different polynomial orders m in the fitting procedure, the D-MV-1 hedge ratio (i.e., the linear polynomial in the fitting procedure) has the best hedging capability for determining the hedge ratio.

Wang, Gang-Jin; Xie, Chi; He, Ling-Yun; Chen, Shou

2014-07-01

441

ROSA: a computer model for optical power ratio calculations  

SciTech Connect

The Ratio of Solid Angles (ROSA) computer code was developed as part of the Crosbyton Solar Power Project (CSPP) for calculation of optical power concentrations due to reflection from a spherical segment mirror. The CSPP is concerned with the development of a technology for producing electric power from steam generated by reflection of the sun's rays from a fixed-mirror solar bowl onto a tracking receiver. In this system, the receiver is cantilevered and pivots about the center of curvature of the mirror. The ROSA code gives optical power concentration ratio profiles at points along the receiver surface. The ROSA code is written for a spherical segment mirror and the rim angle of the mirror is an input variable. Orientation of the axis of symmetry of the bowl is specified in terms of a vertical-east-north coordinate system. Location of the sun relative to this coordinate system is also an input variable. Shading and rim cutoff effects are automatically included in the computation. The code permits any convex surface of revolution as a receiver. Normally a cylinder or a cone would be used. For optimum energy capture, the axis of the receiver should lie along the line from the center of the sun through the center of the bowl. However, tracking errors can cause misalignment of the receiver axis with this line. The code handles such misalignment in terms of misalignment angle input parameters. This report consists of two parts, a technical reference manual and a user's guide. The reference manual provides the background material and derivations necessary for the implementation of the code. Computer listings for ROSA are also included in the reference manual. The user's guide contains an explanation of the input data for the program, special user supplied subroutine requirements, a discussion of the output data, sample output and graphs of sample concentration profiles.

Anderson, R.M.; Ford, W.T.

1984-07-15

442

Ultraviolet Emission Line Ratios of Cataclysmic Variables  

E-print Network

We present a statistical analysis of the ultraviolet emission lines of cataclysmic variables (CVs) based on $\\approx 430$ ultraviolet spectra of 20 sources extracted from the International Ultraviolet Explorer Uniform Low Dispersion Archive. These spectra are used to measure the emission line fluxes of N V, Si IV, C IV, and He II and to construct diagnostic flux ratio diagrams. We investigate the flux ratio parameter space populated by individual CVs and by various CV subclasses (e.g., AM Her stars, DQ Her stars, dwarf novae, nova-like variables). For most systems, these ratios are clustered within a range of $\\sim 1$ decade for log Si IV/C IV $\\approx -0.5$ and log He II/C IV $\\approx -1.0$ and $\\sim 1.5$ decades for log N V/C IV $\\approx -0.25$. These ratios are compared to photoionization and collisional ionization models to constrain the excitation mechanism and the physical conditions of the line-emitting gas. We find that the collisional models do the poorest job of reproducing the data. The photoionization models reproduce the Si IV/C IV line ratios for some shapes of the ionizing spectrum, but the predicted N V/C IV line ratios are simultaneously too low by typically $\\sim 0.5$ decades. Worse, for no parameters are any of the models able to reproduce the observed He II/C IV line ratios; this ratio is far too small in the collisional and scattering models and too large by typically $\\sim 0.5$ decades in the photoionization models.

Christopher W. Mauche; Y. Paul Lee; Timothy R. Kallman

1996-09-20

443

Meteorological Effects on Air/Fuel Ratio  

E-print Network

METEOROLOGICAL EFFECTS ON AIR/FUEL RATIO John L. Ferri GTE Products Corporation Towanda, Pennsylvania ABSTRACT Air is a convenient and inexpensive source of oxygen for most combustion processes. However, the oxygen content of the air...METEOROLOGICAL EFFECTS ON AIR/FUEL RATIO John L. Ferri GTE Products Corporation Towanda, Pennsylvania ABSTRACT Air is a convenient and inexpensive source of oxygen for most combustion processes. However, the oxygen content of the air...

Ferri, J. L.

1984-01-01

444

Effect of high aspect ratio on ITER maintenance design  

SciTech Connect

The International Thermonuclear Experimental Reactor (ITER) baseline machine configuration and auxiliary systems design specify maintainability and repairability as fundamental requirements. Two important maintenance requirements for ITER are a device that is fully remotely maintainable, with the provision for hands-on maintenance wherever possible, and the ability to maintain components with short lives or high failure rates without moving other components or disturbing the machine's internal or external environment. Some of the maintenance tasks are accomplished through the use of specialized remote maintenance equipment that will perform crucial in-vessel and ex-vessel operations. In-vessel maintenance will be performed with a combination of horizontal and vertical access. Since the completion of the Conceptual Design Activity (CDA), systems studies by the US ITER design team have pointed to the possible benefits of a high aspect ratio design (HARD). The alternative HARD has been shown to have better performance characteristics than the present baseline. The HARD machine configuration modified in size a number of major components that must be remotely maintained or replaced. This required reevaluation of the maintenance scenarios of these components with respect to changes in physical accessibility, assembly and disassembly, and remote maintenance equipment. The CDA baseline design and HARD are compared from an assembly and maintenance feasibility perspective for some critical operations. 1 ref., 6 figs.

Herrick, T.J.; Davis, F.C.; Hollis, M.J.; Lousteau, D.C.

1991-01-01

445

Shaping the distribution of vertical velocities of antihydrogen in GBAR  

E-print Network

GBAR is a project aiming at measuring the free fall acceleration of gravity for antimatter, namely antihydrogen atoms ($\\overline{\\mathrm{H}}$). Precision of this timing experiment depends crucially on the dispersion of initial vertical velocities of the atoms as well as on the reliable control of their distribution. We propose to use a new method for shaping the distribution of vertical velocities of $\\overline{\\mathrm{H}}$, which improves these factors simultaneously. The method is based on quantum reflection of elastically and specularly bouncing $\\overline{\\mathrm{H}}$ with small initial vertical velocity on a bottom mirror disk, and absorption of atoms with large initial vertical velocities on a top rough disk. We estimate statistical and systematic uncertainties, and show that the accuracy for measuring the free fall acceleration $\\overline{g}$ of $\\overline{\\mathrm{H}}$ could be pushed below $10^{-3}$ under realistic experimental conditions.

Gabriel Dufour; Pascal Debu; Astrid Lambrecht; Valery Nesvizhevsky; Serge Reynaud; Alexei Voronin

2013-12-19

446

Space of the vertices of relativistic spin networks  

E-print Network

The general solutin to the constraints that define relativistic spin networks vertices is given and their relations with 3-dimensional quantum tetrahedra is dicussed. An alternative way to handle the constraints is also presented.

A. Barbieri

1997-09-30

447

28. DETAILHORIZONTAL METAL SUPPORTS CONNECTING THE VERTICAL PIER OF THE ...  

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

28. DETAIL--HORIZONTAL METAL SUPPORTS CONNECTING THE VERTICAL PIER OF THE TRAVELLING CRANE SUPPORT TO THE WALL. - Navy Yard, Ordnance Building, Intersection of Paulding & Kennon Streets, Washington, District of Columbia, DC

448

Seaglider observations of vertical velocity in the Labrador Sea  

NASA Astrophysics Data System (ADS)

Five Seagliders spent a combined total of over 24 months in the Labrador Sea between 2003-2005. The hydrographic observations made by Seagliders can then be used to estimate vertical water velocities, in stratified regimes (observing internal waves), and mixed regimes (including wintertime mixed layers during deep convection exceeding 1000m deep). Across the seasons and from shelf seas to deep water, the vertical velocity regimes will be described, with particular focus on the velocity measurements during deep convection (Jan-Feb). New results from the high-resolution hydrographic measurements show striking horizontal density variability over tens of kilometers, containing sufficient buoyancy to restratify the region to the degree of stratification observed by Argo floats in April. Concurrently, the vertical velocity measurements show narrow, fast, downwelling plumes between broader and somewhat slower upwelling regions. These new measurements offer a compelling snapshot of deep convection, in both hydrography and vertical velocity, at unprecendented resolution.

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