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1

Cup to disc ratio by optical coherence tomography is abnormal in Multiple Sclerosis  

PubMed Central

Objective To identify and characterize cup to disc ratio (CDR) and related optic nerve head abnormalities in multiple sclerosis (MS) using spectral domain optical coherence tomography (OCT). Background While CDR is routinely assessed by ophthalmologists in the evaluation of glaucoma, CDR and related optic nerve head metrics remain largely unexplored in MS. Design/Methods Cirrus-HD (high density) OCT was used to evaluate average CDR, vertical CDR, optic disc area, optic cup volume and neuro-retinal rim area in 105 MS patients and 88 age-matched healthy individuals. High-contrast (100%) visual acuity, 2.5% low-contrast letter acuity and 1.25% low-contrast letter acuity were assessed in 77 MS patients. Two-sample t-tests were used in the analysis of OCT-derived optic nerve head measures between healthy controls and MS patients. Multivariate regression (accounting for age and gender) was used to assess relationships between optic nerve head measures and visual function. Results Average CDR (p=0.007) and vertical CDR (p=0.005) was greater in MS patients compared to healthy controls, while neuro-retinal rim area was decreased in MS patients (p=0.001). CDR increased with retinal nerve fiber layer (RNFL) thinning (r=?0.29, p=0.001). 2.5% low-contrast (p=0.005) and 1.25% low-contrast letter acuity (p=0.03) were lower in MS patients with higher vertical CDR. Conclusions/Relevance CDR (as determined by spectral domain OCT), is abnormal in MS and correlates with visual function. OCT derived CDR and related optic nerve head metrics may represent an objective measure by which to monitor disease progression, and potentially neuroprotection, in therapeutic MS trials. PMID:21227470

Syc, S.B.; Warner, C.V.; Saidha, S.; Farrell, S.K.; Conger, A.; Bisker, E.R.; Wilson, J.; Frohman, E.M.; Balcer, L.J.; Calabresi, P.A.

2010-01-01

2

Agreement in Assessing Cup-to-Disc Ratio Measurement Among Stereoscopic Optic Nerve Head Photographs, HRT II, and Stratus OCT  

PubMed Central

Purpose To compare the level of agreement between subjective and objective methods in estimating horizontal and vertical cupto-disc ratios (HCDR and VCDR, respectively) to determine if objective techniques may be used as surrogates for subjective cup-to-disc (CDR) estimation. Methods Fifty-one glaucoma patients and 49 control subjects underwent full ophthalmic examination, stereoscopic optic nerve head photographs (ONHPs), confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomography II [HRT II]), and optical coherence tomography (Stratus OCT). The intra-class correlation coefficient (ICC) and Bland Altman plots were used to assess the agreement across the three methods. Repeated measures analysis of variance (ANOVA), Tukey adjustment, and pairwise P values were used to compare the HCDR and VCDR estimates between three clinicians who reviewed photos, Stratus OCT, and HRT II. Results For the clinicians, the agreement in subjectively assessed HCDR and VCDR was substantial (ICC = 0.84 and 0.85, respectively), and for all three methods, overall agreement was good (ICC = 0.75 and 0.77 for the HCDR and VCDR, respectively). Stratus OCT provided the largest overall mean ± SD HCDR (0.68 ± 0.14) and VCDR (0.62 ± 0.13). The smallest overall mean ± SD HCDR was provided by ONHP (0.32 ± 0.16), and the smallest overall mean ± SD VCDR was provided by HRT II (0.26 ± 0.20). Repeated measures ANOVA test demonstrated significant differences across the three methods for glaucomatous (P = 0.0017 and 0.0016, HCDR and VCDR, respectively) and normal (P = 0.0001 for both HCDR and VCDR) eyes. Tukey adjustment demonstrated specific statistical differences between pairs of methods. Conclusions Although the overall agreement between various methods was good, the mean estimates were statistically different. Additional studies are needed to evaluate the sources of variability, their level of significance, and longitudinal agreement between various methods of the CDR estimation. PMID:16778638

Arthur, Stella N.; Aldridge, Aric J.; De León-Ortega, Julio; McGwin, Gerald; Xie, Aiyuan; Girkin, Christopher A.

2015-01-01

3

Nitrogen removal in intermittently aerated vertical flow constructed wetlands: impact of influent COD/N ratios.  

PubMed

The performance response of eight vertical flow constructed wetlands (VFCWs) to different influent COD/N ratios and intermittent aeration in domestic wastewater treatment was investigated. Almost complete nitrification was obtained by intermittent aeration, which well developed alternate anaerobic and aerobic conditions for nitrification and denitrification. Sufficient carbon source supply resulted from influent COD/N ratio of 10 simultaneously obtained high removals of COD (96%), ammonia nitrogen (99%) and total nitrogen (90%) in intermittently aerated VFCWs. In all non-aerated VFCWs, poor nitrification was observed due to oxygen deficiency whilst high COD/N ratios further led to lower COD and nitrogen removal efficiency. The results suggest that intermittent aeration combined with high influent COD/N ratios could achieve high nitrogen removal in VFCWs. PMID:23831745

Fan, Jinlin; Wang, Wengang; Zhang, Bo; Guo, Yeye; Ngo, Huu Hao; Guo, Wenshan; Zhang, Jian; Wu, Haiming

2013-09-01

4

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

5

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

6

Vertical ground motion analysis for submerged pore-elastic media with random void ratios  

Microsoft Academic Search

Recently, very strong vertical ground motions have been recorded during several earthquakes. The vertical motions are the consequence of compressional stresses which are mainly transmitted by pore fluids. For linear elastic analysis of a submerged soil layer, the permeability has a very minor effect on shear-wave response for which pore fluids are not taken into account. But on compressional-wave response,

Chun-Hsien Wu; Jeen-Hwa Wang

2009-01-01

7

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

8

Horizontal-to-Vertical Spectral Ratio and Geological Conditions: The Case of Garner Valley Downhole Array in Southern California  

Microsoft Academic Search

The aim of the present article is to further check the use of the hori- zontal-to-vertical (h\\/v) spectral ratio, which has been recently suggested as an indi- cator of site effects. The data set consists of 1 t0, three-component, high sensitivity accelerograms, recorded at five different depths by the Garner Valley Downhole Array (GVDA), in southern California, with peak ground

N. Theodulidis; Y. Bard; R. Archuleta; M. Bouchon

1996-01-01

9

Spectrum and Charge Ratio of Vertical Cosmic Ray Muons up to Momenta of 2.5 TeV/c  

SciTech Connect

The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5 TeV/c has been obtained by correcting for the overburden of 320 meter water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies up to 10{sup 15} eV.

Schmelling, M.; /Heidelberg, Max Planck Inst.; Hashim, N.O.; /Kenyatta U. Coll.; Grupen, C.; /Siegen U.; Luitz, S.; /SLAC; Maciuc, F.; /Heidelberg, Max Planck Inst.; Mailov, A.; /Siegen U.; Muller, A.-S.; /Karlsruhe, Inst. Technol.; Sander, H.-G.; /Mainz U., Inst. Phys.; Schmeling, S.; /CERN; Tcaciuc, R.; /Siegen U.; Wachsmuth, H.; /CERN; Zuber, K.; /Dresden, Tech. U.

2012-09-14

10

Spectrum and Charge Ratio of Vertical Cosmic Ray Muons up to Momenta of 2.5 TeV/c  

E-print Network

The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5 TeV/c has been obtained by correcting for the overburden of 320 meter water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies up to 10^15 eV.

CosmoALEPH Collaboration; M. Schmelling; N. O. Hashim; C. Grupen; S. Luitz; F. Maciuc; A. Mailov; A. -S. Müller; H. -G. Sander; S. Schmeling; R. Tcaciuc; H. Wachsmuth; K. Zuber

2011-10-19

11

The effect of a changing aspect ratio of aligned cracks on shear wave vertical seismic profiles: A theoretical study  

NASA Astrophysics Data System (ADS)

Rocks containing parallel cracks or preferentially oriented pores behave at low frequencies as transversely isotropic solids. A change in the aspect ratio of these inclusions affects the resultant anisotropy. Curves showing the velocity dependence of the two shear waves on the direction of wave propagation in such rocks intersect in a direction of propagation which depends on the aspect ratio. The angle this direction makes with the symmetry axis of the anisotropic rock decreases for increasing aspect ratio. Characteristic of wave propagation around this angle is a change in the polarization of the leading shear wave. To demonstrate how this affects vertical seismic profile (VSP) measurements, multioffset VSPs at different azimuths are modeled with synthetic seismograms for rocks containing inclusions with a range of aspect ratios. For inclusions with small aspect ratios, the polarization of the initial shear wave may change abruptly as the direction of propagation changes, whereas for large aspect ratios there is no change or the change may be more gradual and spread out over a wider range of directions. This feature may be of interest in assessing the physical character of fluid reservoirs. The observations of changes of polarization and variation of delays between the split shear waves may also be used to monitor changes in stresses in the crust and in monitoring changes during hydrocarbon extraction.

Douma, Jan; Crampin, Stuart

1990-07-01

12

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 ?m, 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 ?m?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

13

Assessment of aerosol's mass concentrations from measured linear particle depolarization ratio (vertically resolved) and simulations  

NASA Astrophysics Data System (ADS)

Multi-wavelength depolarization Raman lidar measurements from Magurele, Romania are used in this study along with simulated mass-extinction efficiencies to calculate the mass concentration profiles of different atmospheric components, due to their different depolarization contribution to the 532 nm backscatter coefficient. Linear particle depolarization ratio (?part) was computed using the relative amplification factor and the system-dependent molecular depolarization. The low depolarizing component was considered as urban/smoke, with a mean ?part of 3%, while for the high depolarizing component (mineral dust) a mean ?part of 35% was assumed. For this study 11 months of lidar measurements were analysed. Two study cases are presented in details: one for a typical Saharan dust aerosol intrusion, 10 June 2012 and one for 12 July 2012 when a lofted layer consisting of biomass burning smoke extended from 3 to 4.5 km height. Optical Properties of Aerosols and Clouds software package (OPAC) classification and conversion factors were used to calculate mass concentrations. We found that calibrated depolarization measurements are critical in distinguishing between smoke-reach aerosol during the winter and dust-reach aerosol during the summer, as well as between elevated aerosol layers having different origins. Good agreement was found between lidar retrievals and DREAM- Dust REgional Atmospheric Model forecasts in cases of Saharan dust. Our method was also compared against LIRIC (The Lidar/Radiometer Inversion Code) and very small differences were observed.

Nemuc, A.; Vasilescu, J.; Talianu, C.; Belegante, L.; Nicolae, D.

2013-11-01

14

Bulletin of the SeismologicalSocietyof America,Vol. 86, No. 2, pp. 306-319, April 1996 Horizontal-to-Vertical Spectral Ratio and Geological Conditions  

E-print Network

-to-Vertical Spectral Ratio and Geological Conditions: The Case of Garner Valley Downhole Array in Southern California accelerograms, recorded at five different depths by the Garner Valley Downhole Array (GVDA), in southern/v) spectral ratio tech- nique provides only partially the information that can be obtained from a downhole

Archuleta, Ralph

15

Application of horizontal-to-vertical (H\\/V) Fourier spectral ratio for analysis of site effect on rock (NEHRP-class B) sites in Taiwan  

Microsoft Academic Search

The frequency-dependent amplification for rock (NEHRP-class B) sites was studied using earthquake ground-motion database collected in Taiwan during implementation of the Taiwan Strong Motion Instrumentation Program. The database used includes several hundred records from earthquakes of ML 4.0–7.3 occurred between 1993 and 2004. The characteristics of amplification were evaluated using the well-known technique of horizontal-to-vertical Fourier spectral ratio (H\\/V) of

Vladimir Yu. Sokolov; Chin-Hsiung Loh; Wen-Yu Jean

2007-01-01

16

HDO and H2O vertical distributions and isotopic ratio in the Venus mesosphere by Solar Occultation at Infrared spectrometer on board Venus Express  

NASA Astrophysics Data System (ADS)

Vertical distributions of the molecular density and mixing ratios of H2O and HDO in the Venus mesosphere have been obtained using Solar Occultation at Infrared (SOIR), a high-resolution (with ?/?? ~ 20,000) echelle spectrometer on Venus Express. The atmosphere is sounded in solar occultation in the range of altitudes from 65 to 130 km. Simultaneous measurements of water vapor lines in the spectral range around 2.61 ?m (3830 cm-1) at altitudes between 70 and 110 km and HDO lines around 3.58 ?m (2715cm-1) at altitudes 70-95 km have been performed. During 1 1/2 years, from April 2006 to August 2007, 54 such measurements have been carried out at different locations of Venus from the north pole to middle south latitudes. Most of the observations at morning and evening terminator correspond to high northern latitudes. We report values of mixing ratio and isotopic ratio obtained for 22 of those measurements occurring in the northern polar area. The average value of the volume mixing ratio of H2O is 1.16 +/- 0.24 ppm and that of HDO is 0.086 +/- 0.020 ppm. A depletion in the mixing ratio for both H2O and HDO is observed at 85 km, which can be related to a depletion of CO2 density above (~95 km) and a possible temperature inversion at these altitudes. The vertical variation of HDO and H2O mixing ratio is within a factor of 2-3 for the analyzed set of observations. The temporal variations have been investigated, and no noticeable variability of H2O is reported at high northern altitudes. The average ratio of HDO/H2O obtained in this work, 240 +/- 25 times the terrestrial ratio, is higher (~1.5 times) than the value of 157 +/- 30 times terrestrial reported for the lower atmosphere. This could be explained by a lower photodissociation of HDO and/or a lower escape rate of D atoms versus H atoms.

Fedorova, A.; Korablev, O.; Vandaele, A.-C.; Bertaux, J.-L.; Belyaev, D.; Mahieux, A.; Neefs, E.; Wilquet, W. V.; Drummond, R.; Montmessin, F.; Villard, E.

2008-12-01

17

Horizontal to vertical spectral ratio measurements in Port-au-Prince (Haiti) area damaged by the 2010 Haiti earthquake  

NASA Astrophysics Data System (ADS)

In order to evaluate ground shaking characteristics due to surface soil layers in the urban area of Port-au-Prince, short-period ambient noise observation has been performed approximately in a 500x500m grid. The HVSR method was applied to this set of 36 ambient noise measurement points to determine a distribution map of soil predominant periods. This map reveals a general increasing trend in the period values, from the Miocene conglomerates in the northern and southern parts of the town to the central and western zones formed of Pleistocene and Holocene alluvial deposits respectively, where the shallow geological materials that cover the basement increase in thickness. Shorter predominant periods (less than 0.3 s) were found in mountainous and neighbouring zones, where the thickness of sediments is smaller whereas longer periods (greater than 0.5 s) appear in Holocene alluvial fans, where the thickness of sediments is larger. The shallow shear-wave velocity structure have been estimated by means of inversion of Rayleigh wave dispersion data obtained from vertical-component array records of ambient noise. The measurements were carried out at one open space located in Holocene alluvial deposits, using 3 regular pentagonal arrays with 5, 10 and 20m respectively. Reliable dispersion curves were retrieved for frequencies between 4.0 and 14 Hz, with phase velocity values ranging from 420m/s down to 270 m/s. Finally, the average shear-wave velocity of the upper 30 m (VS30) was inverted for characterization of this geological unit.

Navarro, M.; Enomoto, T.; Benito, B.; Belizaire, D.; Navarro, D.; García-Jerez, A.; Dorfeuille, J.

2013-05-01

18

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

19

Estimates of site response based on spectral ratio between horizontal and vertical components of ambient vibrations in the source zone of 2001 Bhuj earthquake  

NASA Astrophysics Data System (ADS)

We investigated the site response characteristics of Kachchh rift basin over the meizoseismal area of the 2001, Mw 7.6, Bhuj (NW India) earthquake using the spectral ratio of the horizontal and vertical components of ambient vibrations. Using the available knowledge on the regional geology of Kachchh and well documented ground responses from the earthquake, we evaluated the H/V curves pattern across sediment filled valleys and uplifted areas generally characterized by weathered sandstones. Although our H/V curves showed a largely fuzzy nature, we found that the hierarchical clustering method was useful for comparing large numbers of response curves and identifying the areas with similar responses. Broad and plateau shaped peaks of a cluster of curves within the valley region suggests the possibility of basin effects within valley. Fundamental resonance frequencies (f0) are found in the narrow range of 0.1-2.3 Hz and their spatial distribution demarcated the uplifted regions from the valleys. In contrary, low H/V peak amplitudes (A0 = 2-4) were observed on the uplifted areas and varying values (2-9) were found within valleys. Compared to the amplification factors, the liquefaction indices (kg) were able to effectively indicate the areas which experienced severe liquefaction. The amplification ranges obtained in the current study were found to be comparable to those obtained from earthquake data for a limited number of seismic stations located on uplifted areas; however the values on the valley region may not reflect their true amplification potential due to basin effects. Our study highlights the practical usefulness as well as limitations of the H/V method to study complex geological settings as Kachchh.

Natarajan, Thulasiraman; Rajendran, Kusala

2015-02-01

20

Improved Euler method for the interpretation of potential data based on the ratio of the vertical first derivative to analytic signal  

NASA Astrophysics Data System (ADS)

We propose a new automatic method for the interpretation of potential field data, called the RDAS-Euler method, which is based on Euler's deconvolution and analytic signal methods. The proposed method can estimate the horizontal and vertical extent of geophysical anomalies without prior information of the nature of the anomalies (structural index). It also avoids inversion errors because of the erroneous choice of the structural index N in the conventional Euler deconvolution method. The method was tested using model gravity anomalies. In all cases, the misfit between theoretical values and inversion results is less than 10%. Relative to the conventional Euler deconvolution method, the RDAS-Euler method produces inversion results that are more stable and accurate. Finally, we demonstrate the practicability of the method by applying it to Hulin Basin in Heilongjiang province, where the proposed method produced more accurate data regarding the distribution of faults.

Guo, Can-Can; Xiong, Sheng-Qing; Xue, Dian-Jun; Wang, Lin-Fei

2014-09-01

21

An all-silicon optical platform based on linear array of vertical high-aspect-ratio silicon/air photonic crystals  

NASA Astrophysics Data System (ADS)

An all-silicon optical platform (SiOP) that integrates a linear array of vertical (100-?m-deep) one-dimensional photonic crystals (1D-PhCs), with a different number of elementary silicon/air cells (from 2.5 to 11.5) and featuring a transmission peak around 1.55 ?m, together with U-grooves (125-?m-wide) and end-stop-spacers for coupling/positioning/alignment of readout optical fibers in front of 1D-PhCs is reported. The SiOP is fabricated by electrochemical micromachining and characterized by measuring both reflection and transmission spectra of 1D-PhCs. An experimental/theoretical analysis of 1D-PhC features (transmissivity, quality factor, full-width-half-maximum) in transmission, around 1.55 ?m, as a function of the number of elementary cells is reported.

Surdo, Salvatore; Carpignano, Francesca; Silva, Gloria; Merlo, Sabina; Barillaro, Giuseppe

2013-10-01

22

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

23

Monthly mean vertical profiles of pressure, temperature and water vapour volume mixing ratio in the polar stratosphere and low mesosphere from a multi-year set of MIPAS-ENVISAT limb-scanning measurements  

NASA Astrophysics Data System (ADS)

Measurements performed at polar latitudes by the MIPAS limb-scanning Fourier Transform spectrometer aboard ENVISAT, from July 2002 to March 2004 (FR mission) and January 2005 to April 2010 (OR mission) were analysed with the 2-D tomographic Geofit Multi-Target Retrieval (GMTR) procedure (Dinelli et al., 2010. The MIPAS2D database of MIPAS/ENVISAT measurements retrieved with a multi-target 2-dimensional tomographic approachAtmos. Meas. Techn. Discuss. (AMTD) 2, 2639-2688.) to obtain the MIPAS2D database, and extract more than 386,000 vertical profiles of pressure p, temperature T and water vapour volume mixing ratio Q. They were subdivided into 12 latitudinal classes selected in steps of 5° from 65°N to 90°N and 65°S to 90°S, each vertical profile consisting of values measured at 14 altitude levels from 12 to 60 km. Each latitudinal set was subdivided into 12 monthly sets to determine the multi-year monthly mean vertical profiles of the three parameters: those of p (monthly average standard deviations (SD) 5-15%) provide evidence of marked seasonal variations above 30 km; those of T (SD values of a few percent) show large seasonal variations, with summer maxima at all stratospheric levels; and those of Q (SD lower than 20% from 20 to 50 km) present values ranging in general between 2 and 6 ppmv at the 12-25 km levels and 4 and 7 ppmv at higher altitudes. To verify the reliability of the MIPAS results, the pressure profiles are compared with those obtained from radiosounding data-sets taken at Arctic and Antarctic sites from 2000 to 2003; those of T with both radiosounding measurements and MLS/Aura satellite data from 2005 to 2010; and those of Q with the MLS/Aura satellite data, finding a substantial agreement in all cases. Comparison of MIPAS pressure and temperature profiles with pre ozone-hole CIRA models at 70° and 80° latitudes highlights the variations occurring in the polar atmosphere over the last 3 decades, with relative pressure decreases of 5-10% on average, and overall average decreases in temperature of 0.4 and 2.0 K in the Arctic and Antarctica, respectively. Using the MIPAS profiles of p, T and Q, the monthly mean vertical profiles of absolute humidity were also calculated, from which the monthly values of stratospheric water vapour content from 12 to 50 km were determined, varying between 0.0047 and 0.0070 mm at Arctic latitudes and between 0.0026 and 0.0055 mm at Antarctic latitudes.

Tomasi, Claudio; Petkov, Boyan; Maria Dinelli, Bianca; Castelli, Elisa; Arnone, Enrico; Papandrea, Enzo

2011-10-01

24

Monolithic vertical combdrive actuators for adaptive optics  

Microsoft Academic Search

High aspect ratio vertical combdrive actuators are demonstrated which advance the capabilities and applications of SOI-MEMS by adding additional independent degrees of freedom of operation: both upward and downward vertical pistoning motion as well as bi-directional pure rotation. The methodology for the first time enables monolithic fabrication of isolated vertical combdrive sets in the SOI device layer, with combfinger self-alignment

Veliko MilanoviC; Sunghoon Kwon; L. P. Lee

2002-01-01

25

Automated detection of kinks from blood vessels for optic cup segmentation in retinal images  

Microsoft Academic Search

The accurate localization of the optic cup in retinal images is important to assess the cup to disc ratio (CDR) for glaucoma screening and management. Glaucoma is physiologically assessed by the increased excavation of the optic cup within the optic nerve head, also known as the optic disc. The CDR is thus an important indicator of risk and severity of

D. W. K. Wong; J. Liu; J. H. Lim; H. Li; T. Y. Wong

2009-01-01

26

Method of detecting kink-bearing vessels in a retinal fundus image  

Microsoft Academic Search

Glaucoma is the second leading cause of blindness worldwide. The risk of glaucoma can be determined by calculating the cup to disc ratio in retinal fundus images. To accurately detect the optic cup, kinks or bends in small and medium vessels are important indicators of the cup boundary. In this paper, we present a method of detecting such vessels, through

D. W. K. Wong; Jiang Liu; Joo Hwee Lim; Ngan Meng Tan; Zhuo Zhang; Huiqi Li; Shijian Lu; Tien Yin Wong

2010-01-01

27

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.

28

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

29

Vertical axis wind turbines  

Microsoft Academic Search

A vertical wind turbine having vertical blades, each blade being connected intermediate its ends by a hinge to a support arm having a hub that enables the blades to rotate around a vertical axis, a tie wire connected to the blade at positions spaced along the blade from the hinge, said tie wire engaging a spring-loaded pulley disposed inwardly of

P. E. Delgado; B. A. Holmes

1981-01-01

30

Vertical Map Storage.  

ERIC Educational Resources Information Center

Discusses the superiority of vertical filing of maps in compressor-style vertical units over horizontal filing in drawers, emphasizing such factors as physical protection of the collection, ease of filing and retrieval, and efficient use of space. Disadvantages of vertical filing are also reviewed. (Author/JL)

Perry, Joanne M.

1982-01-01

31

Vertical axis wind turbines  

DOEpatents

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

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

2011-03-08

32

Vertical axis wind turbines  

Microsoft Academic Search

A vertical axis wind turbine comprises one or more aerofoil section blades attached to a support structure. The blade has at least one part thereof which is acted on by centrifugal forces as the blade rotates with the support structure and thereby caused to increase its angle of inclination to the vertical axis when the speed of rotation increases beyond

Musgrove

1978-01-01

33

Mixed convection flow in narrow vertical ducts  

Microsoft Academic Search

The mixed convection flow in a vertical duct is analysed under the assumption that e, the ratio of the duct width to the length over which the wall is heated, is small. It is assumed that a fully developed Poiseuille flow has already been set up in the duct before heat from the wall causes this to be changed by

T. Mahmood; J. H. Merkin

1989-01-01

34

Influence of moisture content on pressure ratio of rape seeds  

Microsoft Academic Search

The horizontal to vertical pressure ratio k is one of the three most important parameters required for the cal- culation of stresses that granular materials exert on the wall and floor of a silo, introduced by JANSSEN (1895). The author assumed that the vertical pressure was uni- form in a horizontal section of the silo and that ratio k was

R. RUSINEK; J. ?UKASZUK

2004-01-01

35

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

36

Vertical comb array microactuators  

Microsoft Academic Search

A vertical actuator fabricated using a trench-refilled-with-polysilicon (TRiPs) process technology and employing an array of vertical oriented comb electrodes is presented. This actuator structure provides a linear drive to deflection characteristic and a large throw capability which are key features in many sensors, actuators and micromechanisms. The actuation principle and relevant theory is developed, including FastCap simulations for theoretical verification.

Arjun Selvakumar; Khalil Najafi

2003-01-01

37

Vertical axis wind turbines  

SciTech Connect

A vertical wind turbine having vertical blades, each blade being connected intermediate its ends by a hinge to a support arm having a hub that enables the blades to rotate around a vertical axis, a tie wire connected to the blade at positions spaced along the blade from the hinge, said tie wire engaging a spring-loaded pulley disposed inwardly of the blades, the arrangement being such that when the angle of inclination of the blades to the vertical axis alters under the action of centrifugal force the tie wire exerts a force on the pulley opposing the spring force whereby as the turbine speeds up the blades will remain at a predetermined angle of inclination until the force exerted by the wire exceeds the force of the spring. One end of the tie wire can be connected to a position on one blade and connected to another position on another blade so that all of the blades adopt the same angle of inclination to the vertical axis.

Delgado, P.E.; Holmes, B.A.

1981-06-23

38

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

39

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

40

Construction & Therapy Vertical Integration  

E-print Network

Construction & Therapy Vertical Integration Pilot Project Collaboration Partners Department to work with a local population to realize direct construction. Titled Construction & Therapy the studio will be documented and developed as a therapeutic exercise. The production of the welcome building will be delivered

Strathclyde, University of

41

Vertical distribution of acetonitrile in the atmosphere  

NASA Technical Reports Server (NTRS)

The presence of acetonitrile in the atmosphere was confirmed by results of surface and stratospheric investigations. Stratospheric measurements give mixing ratios typically decreasing with height from 3 ppt at 25 km to 0.5 ppt at 40 km. Measurements at the Earth's surface are less unanimous, although a ground level background mixing ratio of a few times 10 ppt seems realistic. Measurements are compatible with a small global surface source of acetonitrile and a small tropospheric loss. The vertical distribution of acetonitrile presented in consistent with general knowledge of its atmospheric chemistry.

Ingels, J.; Nevejans, D.; Arijs, E.

1985-01-01

42

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

43

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.

44

'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

45

Vertical slender jets  

NASA Technical Reports Server (NTRS)

The shape of a vertical slender jet of fluid falling steadily under the force of gravity is studied. The problem is formulated as a nonlinear free boundary-value problem for the potential. Surface tension effects are neglected. The use of perturbation expansions results in a system of equations that can be solved by an efficient numerical procedure. Computations were made for jets issuing from orifices in various shapes including an ellipse, a rectangle, and an equilateral triangle. Computational results are presented illustrating the propagation of discontinuities and the formation of thin sheets of fluid.

Geer, J. F.; Strikwerda, J. C.

1980-01-01

46

NSTX Passive Structure and Vertical Stability  

NASA Astrophysics Data System (ADS)

The National Spherical Torus Experiment (NSTX) is a low aspect ratio device with a plasma current of 1.0 MA. Low aspect ratio plasmas are known to have better n=0 axisymmetric stability than higher aspect ratio configurations. Vertical stability is critically dependent on the passive structure that surrounds the plasma. NSTX has a SS outer vacuum vessel, an Inconel center casing, and Cu passive plates. The passive plates in NSTX consist of sectors each 30 degrees in toroidal extent which are connected electrically to the vacuum vessel wall via SS supports. If these Cu sectors are connected to form a saddle loop with a single toroidal break axisymmetric stability analysis predicted acceptable growth times in the range of 100-300 ms. 3D electromagnetic calculations however, indicated that the currents did not remain in the Cu plates but were shared with the vacuum vessel through the SS supports. This produced an unacceptable field perturbation near the toroidal break. To avoid this nonaxisymmetric perturbation, the direct connections between all passive plate sectors were disconnected. This leads to a decrease in the vertical growth times that approachs a factor of 10-15. Analysis will be presented to show what plasma configurations may be produced with NSTX feedback control in the present machine configuration.

Kessel, C. E.; Bialek, J.

1999-11-01

47

ON-LINE TOOLS FOR PROPER VERTICAL POSITIONING OF VERTICAL SAMPLING INTERVALS DURING SITE ASSESSMENT  

EPA Science Inventory

This presentation presents on-line tools for proper vertical positioning of vertical sampling intervals during site assessment. Proper vertical sample interval selection is critical for generate data on the vertical distribution of contamination. Without vertical delineation, th...

48

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

49

Vertical allometry: fact or fiction?  

PubMed

In pharmacokinetics, vertical allometry is referred to the clearance of a drug when the predicted human clearance is substantially higher than the observed human clearance. Vertical allometry was initially reported for diazepam based on a 33-fold higher human predicted clearance than the observed human clearance. In recent years, it has been found that many other drugs besides diazepam, can be classified as drugs which exhibit vertical allometry. Over the years, many questions regarding vertical allometry have been raised. For example, (1) How to define and identify the vertical allometry? (2) How much difference should be between predicted and observed human clearance values before a drug could be declared 'a drug which follows vertical allometry'? (3) If somehow one can identify vertical allometry from animal data, how this information can be used for reasonably accurate prediction of clearance in humans? This report attempts to answer the aforementioned questions. The concept of vertical allometry at this time remains complex and obscure but with more extensive works one can have better understanding of 'vertical allometry'. PMID:24534003

Mahmood, Iftekhar; Boxenbaum, Harold

2014-04-01

50

Vertically emitting terahertz quantum cascade ring lasers  

NASA Astrophysics Data System (ADS)

We describe the fabrication and operation of vertically emitting distributed feedback quantum cascade ring lasers operating in the terahertz frequency range. A twofold increase in radiation efficiency is observed as compared to Fabry-Pérot lasers. The emitters exhibit a robust single-mode operation around 3.2 THz with a side mode suppression ratio higher than 30 dB. Modal and threshold characteristics are investigated by performing finite element simulations with results in good agreement with experiments. The ring-shaped resonator facilitates beam collimation which results in a symmetric far-field profile.

Mujagi?, Elvis; Deutsch, Christoph; Detz, Hermann; Klang, Pavel; Nobile, Michele; Andrews, Aaron Maxwell; Schrenk, Werner; Unterrainer, Karl; Strasser, Gottfried

2009-07-01

51

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

52

Vertically reciprocating auger  

NASA Technical Reports Server (NTRS)

The mathematical model and test results developed for the Vertically Reciprocating Auger (VRA) are summarized. The VRA is a device capable of transporting cuttings that result from below surface drilling. It was developed chiefly for the lunar surface, where conventional fluid flushing while drilling would not be practical. The VRA uses only reciprocating motion and transports material through reflections with the surface above. Particles are reflected forward and land ahead of radially placed fences, which prevent the particles from rolling back down the auger. Three input wave forms are considered to drive the auger. A modified sawtooth wave form was chosen for testing, over a modified square wave or sine wave, due to its simplicity and effectiveness. The three-dimensional mathematical model predicted a sand throughput rate of 0.2667 pounds/stroke, while the actual test setup transported 0.075 pounds/stroke. Based on this result, a correction factor of 0.281 is suggested for a modified sawtooth input.

Etheridge, Mark; Morgan, Scott; Fain, Robert; Pearson, Jonathan; Weldi, Kevin; Woodrough, Stephen B., Jr.

1988-01-01

53

The Gains from Vertical Scaling  

ERIC Educational Resources Information Center

It is often assumed that a vertical scale is necessary when value-added models depend upon the gain scores of students across two or more points in time. This article examines the conditions under which the scale transformations associated with the vertical scaling process would be expected to have a significant impact on normative interpretations…

Briggs, Derek C.; Domingue, Ben

2013-01-01

54

Measuring Growth with Vertical Scales  

ERIC Educational Resources Information Center

A vertical score scale is needed to measure growth across multiple tests in terms of absolute changes in magnitude. Since the warrant for subsequent growth interpretations depends upon the assumption that the scale has interval properties, the validation of a vertical scale would seem to require methods for distinguishing interval scales from…

Briggs, Derek C.

2013-01-01

55

Vertical axis wind turbine motor  

Microsoft Academic Search

A wind power conversion turbine motor has a body supported to rotate about a vertical axis and carrying a plurality of substantially upright vanes substantially spaced from the vertical axis and circumferentially spaced from one another so that wind thrusting propulsively against outer sides of the vanes can move across the space circumscribed by the vanes and thrust propulsively against

Rumsey

1977-01-01

56

Modeling Verticality Estimation During Locomotion  

E-print Network

for gravitational vertical estimation is introduced including an inclinometer combined with an imu, as proposed´eal, Qc, Canada 3 Laboratoire de Physiologie de la Perception et de l'Action, Coll`ege de France, Paris, France Abstract Estimation of the gravitational vertical is a fundamental problem faced by locomoting

Hayward, Vincent

57

A theoretical investigation of average H\\/V ratios  

Microsoft Academic Search

The mode summation method and a finite difference technique are applied to investigate the spectral ratio between the horizontal and vertical components (H\\/V ratio) of ambient vibrations and to explore the variation of the resonance frequency and the amplitude and shape of polarization as a function of the structure and the source positions. Layered structural models are used by assuming

Donat Fäh; Fortunat Kind; Domenico Giardini

2001-01-01

58

Aircraft measurement of HONO vertical profiles over a forested region  

Microsoft Academic Search

Here we present the first HONO vertical profiles in the atmospheric boundary layer (BL) and the lower free troposphere (FT) over a forested region in northern Michigan and the neighboring Great Lakes, measured from a small aircraft in summer of 2007. The HONO mixing ratios ranged from 4 to 17 pptv in the FT and from 8 to 74 pptv

Ning Zhang; Xianliang Zhou; Paul B. Shepson; Honglian Gao; Marjan Alaghmand; Brian Stirm

2009-01-01

59

Vertically Aligned Nanocomposite Thin Films  

E-print Network

Vertically aligned nanocomposite (VAN) thin films have recently stimulated significant research interest to achieve better material functionality or multifunctionalities. In VAN thin films, both phases grow epitaxially in parallel on given...

Bi, Zhenxing

2012-07-16

60

Vertically scanned laser sheet microscopy  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

61

Vertical axis wind turbine airfoil  

DOEpatents

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

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

2012-12-18

62

The Golden Ratio  

ERIC Educational Resources Information Center

The Golden Ratio is sometimes called the "Golden Section" or the "Divine Proportion", in which three points: A, B, and C, divide a line in this proportion if AC/AB = AB/BC. "Donald in Mathmagicland" includes a section about the Golden Ratio and the ratios within a five-pointed star or pentagram. This article presents two computing exercises that…

Hyde, Hartley

2004-01-01

63

Bicycle Gears- Ratios  

NSDL National Science Digital Library

Students experiment with and learn about the gear ratios on a bicycleâthus enhancing their understanding of circumference of a circle, proportions, etc. Actual gear ratio would be the ratio between the front and rear sprocket, NOT between pedal and rear wheel.

2011-01-01

64

The Genetics of POAG in Black South Africans: A Candidate Gene Association Study.  

PubMed

Multiple loci have been associated with either primary open angle glaucoma (POAG) or heritable ocular quantitative traits associated with this condition. This study examined the association of these loci with POAG, with central corneal thickness (CCT), vertical cup-to-disc ratio (VCDR) and with diabetes mellitus in a group of black South Africans (215 POAG cases and 214 controls). The population was homogeneous and distinct from other African and European populations. Single SNPs in the MYOC, COL8A2, COL1A1 and ZNF469 gene regions showed marginal associations with POAG. No association with POAG was identified with tagging SNPs in TMCO1, CAV1/CAV2, CYP1B1, COL1A2, COL5A1, CDKN2B/CDKN2BAS-1, SIX1/SIX6 or the chromosome 2p16 regions and there were no associations with CCT or VCDR. However, SNP rs12522383 in WDR36 was associated with diabetes mellitus (p = 0.00008). This first POAG genetic association study in black South Africans has therefore identified associations that require additional investigation in this and other populations to determine their significance. This highlights the need for larger studies in this population if we are to achieve the goal of facilitating early POAG detection and ultimately preventing irreversible blindness from this condition. PMID:25669751

Williams, Susan E I; Carmichael, Trevor R; Allingham, R Rand; Hauser, Michael; Ramsay, Michele

2015-01-01

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

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

67

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

68

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

69

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

70

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

71

Neglected locked vertical patellar dislocation.  

PubMed

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

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

2012-09-01

72

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

73

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

74

Convection in vertical Bridgman configurations  

NASA Technical Reports Server (NTRS)

We are interested in tracing the convective profiles of vertical Bridgman growth in two configurations, the pure Rayleigh convective mode and the combined Rayleigh-Marangoni mode. In order to do so, we conducted a numerical investigation that involved a finite volume calculation. The governing equations were integrated about a cell volume, using the Gauss Theorem and the volume variables like temperature and velocity were related to the surface variables. In order to solve for the pressure field, we employed the continuity equation and the residuals resulted in a Poisson equation. Results and comments for the Rayleigh and Marangoni problems in a vertical cylinder or Bridgman configuration are given.

Narayanan, Ranga

1991-01-01

75

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

76

Suppression of vertical instability in elongated current-carrying plasmas by applying stellarator rotational transforma)  

NASA Astrophysics Data System (ADS)

The passive stability of vertically elongated current-carrying toroidal plasmas has been investigated in the Compact Toroidal Hybrid, a stellarator/tokamak hybrid device. In this experiment, the fractional transform f, defined as the ratio of the imposed external rotational transform from stellarator coils to the total rotational transform, was varied from 0.04 to 0.50, and the elongation ? was varied from 1.4 to 2.2. Plasmas that were vertically unstable were evidenced by motion of the plasma in the vertical direction. Vertical drifts are measured with a set of poloidal field pickup coils. A three chord horizontally viewing interferometer and a soft X-ray diode array confirmed the drifts. Plasmas with low fractional transform and high elongation are the most susceptible to vertical instability, consistent with analytic predictions that the vertical mode in elongated plasmas can be stabilized by the poloidal field of a relatively weak stellarator equilibrium.

ArchMiller, M. C.; Cianciosa, M. R.; Ennis, D. A.; Hanson, J. D.; Hartwell, G. J.; Hebert, J. D.; Herfindal, J. L.; Knowlton, S. F.; Ma, X.; Maurer, D. A.; Pandya, M. D.; Traverso, P.

2014-05-01

77

Compression Ratio Adjuster  

NASA Technical Reports Server (NTRS)

New mechanism alters compression ratio of internal-combustion engine according to load so that engine operates at top fuel efficiency. Ordinary gasoline, diesel and gas engines with their fixed compression ratios are inefficient at partial load and at low-speed full load. Mechanism ensures engines operate as efficiently under these conditions as they do at highload and high speed.

Akkerman, J. W.

1982-01-01

78

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

79

Carbon nanotube films change Poisson's ratios from negative to positive  

NASA Astrophysics Data System (ADS)

In this paper, a discovery is reported that carbon nanotube (CNT) films can change in-plane Poisson's ratios from negative to positive during a uniaxial tensile loading. First, in situ experimental investigations of the deformation fields about the CNT films fabricated using vertically aligned CNT arrays are performed by digital speckle correlation method, the novel phenomenon for changing Poisson's ratio from negative to positive during the stretching process is discovered. Furthermore, the physical mechanisms for changing the Poisson's ratio from negative to positive are explained based on the interactions among CNTs. Finally, a potential engineering application for designing intelligent connector is proposed based on the intriguing Poisson's ratio of CNT films.

Ma, Yin Ji; Yao, Xue Feng; Zheng, Quan Shui; Yin, Ya Jun; Jiang, Dong Jie; Xu, Guang Hui; Wei, Fei; Zhang, Qiang

2010-08-01

80

Vertical Instability at IPNS RCS.  

SciTech Connect

The rapid cycling synchrotron (RCS) of the intense pulsed neutron source (IPNS) at ANL accelerates > 3.0 times 10{sup 12} protons from 50 MeV to 450 MeV with 30-Hz repetition frequency. During the acceleration cycle, the rf frequency varies from 2.21 MHz to 5.14 MHz. Presently, the beam current is limited by a vertical instability. By analyzing turn-by-turn beam position monitor (BPM) data, large- amplitude mode 0 and mode 1 vertical beam centroid oscillations were observed in the later part of the acceleration cycle. The oscillations start in the tail of the bunch, build up, and remain localized in the tail half of the bunch. This vertical instability was compared with a head-tail instability that was intentionally induced in the RCS by adjusting the trim sextupoles. It appears that our vertical instability is not a classical head-tail instability [1]. More data analysis and experiments were performed to characterize the instability.

Wang, S.; Brumwell, F. R.; Dooling, J. C.; Harkay, K. C.; Kustom, R.; McMichael, G. E.; Middendorf, M. E.; Nassiri, A.; Accelerator Systems Division (APS)

2008-01-01

81

Vertical capacitive SiBARs  

Microsoft Academic Search

This work introduces high frequency, vertical silicon bulk acoustic resonators (SiBAR). A combination of the new resonator structures with much larger transduction area and the HARPSS fabrication process is used to demonstrate high frequency capacitive resonators with significantly lower impedances compared to the previous capacitive resonators. Impedances as low as a few kilo-Ohms and quality factors in the range of

Siavash Pourkamali; Gavin K. Ho; Farrokh Ayazi

2005-01-01

82

Long wavelength vertical cavity lasers  

Microsoft Academic Search

The need for low cost, high speed telecommunication sources demands the maturation of long wavelength vertical cavity lasers (VCLs). Both long haul fiber optic systems and gigabit ethernet links are potential markets for 1.3 and 1.55 micron VCLs. This past year has seen much progress to this end, but the emerging technology has yet to be determined. This paper overviews

K. A. Blacka; P. Abraham; A. Keating; Y. J. Chiu; E. L. Hu; J. E. Bowers

1999-01-01

83

Th ratio as a proxy for past changes in opal fluxes in the Indian sector of the Southern Ocean  

E-print Network

The 231 Pa/230 Th ratio as a proxy for past changes in opal fluxes in the Indian sector of particles. In this study we compare the 230 Th normalized vertical fluxes of both total sediments and opal (ACC). We observe a better correlation between the 231 Pa/230 Th ratios and the vertical opal fluxes

Demouchy, Sylvie

84

Vertical Sextants give Good Sights  

NASA Astrophysics Data System (ADS)

Many texts stress the need for marine sextants to be held precisely vertical at the instant that the altitude of a heavenly body is measured. Several authors lay particular emphasis on the technique of the instrument in a small arc about the horizontal axis to obtain a good sight. Nobody, to the author's knowledge, however, has attempted to quantify the errors involved, so as to compare them with other errors inherent in determining celestial position lines. This paper sets out to address these issues and to pose the question: what level of accuracy of vertical alignment can reasonably be expected during marine sextant work at sea ?When a heavenly body is brought to tangency with the visible horizon it is particularly important to ensure that the sextant is held in a truly vertical position. To this end the instrument is rocked gently about the horizontal so that the image of the body describes a small arc in the observer's field of vision. As Bruce Bauer points out, tangency with the horizon must be achieved during the process of rocking and not a second or so after rocking has been discontinued. The altitude is recorded for the instant that the body kisses the visible horizon at the lowest point of the rocking arc, as in Fig. 2. The only other visual clue as to whether the sextant is vertical is provided by the right angle made by the vertical edge of the horizon glass mirror with the horizon. There may also be some input from the observer's sense of balance and his hand orientation.

Dixon, Mark

85

Wind tunnel investigation of a 14 foot vertical axis windmill  

NASA Technical Reports Server (NTRS)

A full scale wind tunnel investigation was made to determine the performance characteristics of a 14 ft diameter vertical axis windmill. The parameters measured were wind velocity, shaft torque, shaft rotation rate, along with the drag and yawing moment. A velocity survey of the flow field downstream of the windmill was also made. The results of these tests along with some analytically predicted data are presented in the form of generalized data as a function of tip speed ratio.

Muraca, R. J.; Guillotte, R. J.

1976-01-01

86

Ratio and Fractions.  

ERIC Educational Resources Information Center

Findings on ratio and on fractions from a research project on strategies and errors in secondary mathematics are discussed, with typical errors described. Pupils seemed to learn rules without understanding. (MNS)

Hart, K.

1983-01-01

87

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

88

Depolarization Ratio Measurements From the CALIPSO Spaceborne Lidar  

Microsoft Academic Search

Thanks to its sensitivity to optically thin atmospheric layers and its vertical variability, the lidar is a instrument perfectly suited to the study of cirrus clouds and aerosols. Moreover, most recent lidars are equipped with polarization-sensitive detectors that allow the retrieval of the depolarization ratio. Being, on a first approximation, only sensitive to the shape of particles, this measurement gives

V. Noel; D. M. Winker; C. Trepte; M. Vaughan; Y. Hu; R. Khuen

2006-01-01

89

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

90

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

91

Vertically Integrated Circuits at Fermilab  

SciTech Connect

The exploration of 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. For the first time, Fermilab has organized a 3D MPW run, to which more than 25 different designs have been submitted by the consortium.

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

2010-01-01

92

Vertical combustor for refuse combustion  

Microsoft Academic Search

A vertical combustor for refuse-particle combustion was analyzed for waste-to-energy recovery. A one-dimensional model was constructed that consisted of fuel particles, inert solid particles, and the gaseous mixture. The gaseous mixture was divided further into six chemical species that are involved in combustion at temperatures below about 2000°F. It was concluded that such combustors may be viable in the United

Chung

1981-01-01

93

Vertical Structure of the Atmosphere  

NSDL National Science Digital Library

Earth is surrounded by a protective atmosphere, composed of nitrogen, oxygen, and argon, and trace amounts of other gases, that protects Earth's surface from damaging solar radiation and plays a major role in water and energy transport. This interactive feature shows the vertical structure of the atmosphere. Viewers can see the regions of the atmosphere, some of the objects (natural and man-made) found at various altitudes, as well as the variations in air temperature and pressure with altitude.

94

Vertical Height of the Atmosphere  

NSDL National Science Digital Library

This is a lesson about the vertical dimension of the atmosphere and includes four activities. Activity 1 Introduces concepts related to distance, including length and height and units of measurement. Students are asked to make comparisons of distances. In activity 2, students learn about the vertical profile of the atmosphere. They work with a graph and plot the heights of objects and the layers of the atmosphere: troposphere, stratosphere, mesosphere, thermosphere, and exosphere. In activity 3, students learn about other forms of visual displays using satellite imagery. They compare images of the same weather feature, a hurricane, using two different images from MODIS and CALIPSO. One image is looking down on the hurricane from space, the other looks through the hurricane to display a profile of the hurricane. Activity 4 reinforces the concept of the vertical nature of the atmosphere. Students will take a CALIPSO satellite image that shows a profile of the atmosphere and use this information to plot mountains and clouds on their own graph of the atmosphere. The recommended order for the activities is to complete the first two activities on day one, and the second two activities on day two. Each day will require approximately 1 to 1.5 hours.

95

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

96

Bulletin of the Seismological Society of America, Vol. 92, No. 8, pp. 31523164, December 2002 Properties of Vertical Ground Motions  

E-print Network

Properties of Vertical Ground Motions by Igor A. Beresnev, Amber M. Nightengale, and Walter J. Silva Abstract A typical engineering approach to developing site-specific design ver- tical ground motions starts with rock investigated the ratio of SV- to P-wave spectra of the vertical component of ground motions from significant

Beresnev, Igor

97

Twins Vertices in Hypergraphs Raoul Medina1  

E-print Network

Twins Vertices in Hypergraphs Raoul Medina1 and Caroline Noyer and Olivier Raynaud2 Research Report;Abstract Twin vertices in graphs correspond to vertices sharing the same neighbor- hood. We propose an extension to hypergraphs of the concept of twin ver- tices. For this we give two characterizations of twin

Boyer, Edmond

98

7, 22492274, 2007 Vertical ozone over  

E-print Network

ACPD 7, 2249­2274, 2007 Vertical ozone over Eastern Mediterranean and Central Europe P. D a Creative Commons License. Atmospheric Chemistry and Physics Discussions Vertical ozone measurements (kalabokas pavlos@yahoo.gr) 2249 #12;ACPD 7, 2249­2274, 2007 Vertical ozone over Eastern Mediterranean

Boyer, Edmond

99

On the vertical distribution of carbon monoxide over Bay of Bengal during winter: Role of water vapour and vertical updrafts  

NASA Astrophysics Data System (ADS)

The differences in the spatial pattern of column carbon monoxide (CO) and in-situ measured near-surface CO over Bay of Bengal (BoB) during winter were examined in the light of vertical distribution of CO as retrieved from MOPITT (Measurements Of Pollution In The Troposphere) on board Terra spacecraft. The column CO showed relatively high values over southern-BoB whereas the near-surface CO showed low mixing ratio indicating the existence of significant amount of CO at higher altitudes. The vertical profiles of CO over the BoB region retrieved from MOPITT exhibit a high altitude peak around ~9 km altitude region. The role of water vapour and convective activity/vertical updrafts in establishing the observed vertical profile of CO was investigated. It is found that CO got uplifted to the higher altitude due to updrafts and water vapour caused depletion of CO at lower altitudes which appeared as an apparent high in CO mixing ratio at higher altitude relative to that over lower altitude. The role of water vapour in the destruction of CO was confirmed by box model simulations. Airmass back-trajectory analysis showed that the long range transport from lower troposphere/boundary layer was also partially responsible for higher mixing ratios at higher altitude. In addition, a comparison of in-situ measured near-surface CO and those retrieved from MOPITT using retrieval algorithm Versions 4 and 5 showed that the points of discrepancy have reduced in the Version 5. Biomass burning and anthropogenic activities taking place over the Myanmar landmass was found to be responsible for the hot spots of near-surface-CO over the northeast-BoB.

Girach, I. A.; Nair, Prabha R.

2014-09-01

100

Area Ratios of Quadrilaterals.  

ERIC Educational Resources Information Center

Shows that the ratio of the area of the quadrilateral formed by joining the kth points to the area of the original quadrilateral is constant whether it is convex or concave quadrilateral. Presents many geoboard or dot paper diagrams and geometrical expresssions. (YP)

Anderson, David R.; Arcidiacono, Michael J.

1989-01-01

101

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

102

?Vertical Sextants give Good Sights?  

NASA Astrophysics Data System (ADS)

Mark Dixon suggests (Forum, Vol. 50, 137) that nobody thus far has attempted to quantify the errors from tilt that arise while observing with the marine sextant. The issue in fact, with the related problem of what exactly is the axis about which the sextant is rotated whilst being (to define the vertical), was the subject of a lively controversy in the first two volumes of this Journal some fifty years ago. Since the consensus of opinion seems to have been that the maximum error does not necessarily occur at 45 degrees, whereas Dixon's table suggests that it does, some reiteration of the arguments may be in order.

Richey, Michael

103

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

104

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

105

Vertical Diffusivities of Active and Passive Tracers  

NASA Technical Reports Server (NTRS)

The climate models that include a carbon-cycle need the vertical diffusivity of a passive tracer. Since an expression for the latter is not available, it has been common practice to identify it with that of salt. The identification is questionable since T, S are active, not passive tracers. We present the first derivation of the diffusivity of a passive tracer in terms of Ri (Richardson number) and Rq (density ratio, ratio of salinity over temperature z-gradients). The following results have emerged: (a) The passive tracer diffusivity is an algebraic function of Ri, Rq. (b) In doubly stable regimes (DS, partial derivative of T with respect to z > 0, partial derivative of S with respect to z < 0), the passive scalar diffusivity is nearly the same as that of salt/heat for any values of Rq < 0 and Ri > 0. (c) In DC regimes (diffusive convection, partial derivative of T with respect to z < 0, partial derivative of S with respect to z < 0, Rq > 1), the passive scalar diffusivity is larger than that of salt. At Ri = O(1), it can be more than twice as large. (d) In SF regimes (salt fingers, partial derivative of T with respect to z > 0, partial derivative of S with respect to z > 0, Rq < 1), the passive scalar diffusivity is smaller than that of salt. At Ri = O(1), it can be less than half of it. (e) The passive tracer diffusivity predicted at the location of NATRE (North Atlantic Tracer Release Experiment) is discussed. (f) Perhaps the most relevant conclusion is that the common identification of the tracer diffusivity with that of salt is valid only in DS regimes. In the Southern Ocean, where there is the largest CO2 absorption, the dominant regime is diffusive convection discussed in (c) above.

Canuto, V. M.; Cheng, Y.; Howard, A. M.

2010-01-01

106

Laser tracking for vertical control  

NASA Technical Reports Server (NTRS)

The Global Laser Tracking Network has provided LAGEOS ranging data of high accuracy since the first MERIT campaign in late 1983 and we can now resolve centimeter-level three dimensional positions of participating observatories at monthly intervals. In this analysis, the station height estimates have been considered separately from the horizontal components, and can be determined by the strongest stations with a formal standard error of 2 mm using eight years of continuous observations. The rate of change in the vertical can be resolved to a few mm/year, which is at the expected level of several geophysical effects. In comparing the behavior of the stations to that predicted by recent models of post-glacial rebound, we find no correlation in this very small effect. Particular attention must be applied to data and survey quality control when measuring the vertical component, and the survey observations are critical components of the geodynamic results. Seasonal patterns are observed in the heights of most stations, and the possibility of secular motion at the level of several millimeters per year cannot be excluded. Any such motion must be considered in the interpretation of horizontal inter-site measurements, and can help to identify mechanisms which can cause variations which occur linearly with time, seasonally, or abruptly.

Dunn, Peter; Torrence, Mark; Pavlis, Erricos; Kolenkiewicz, Ron; Smith, David

1993-01-01

107

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

108

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

109

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

110

Turbulent vertical diffusivity in the sub-tropical stratosphere  

NASA Astrophysics Data System (ADS)

Vertical (cross-isentropic) mixing is produced by small-scale turbulent processes which are still poorly understood and parametrized in numerical models. In this work we provide estimates of local equivalent diffusion in the lower stratosphere by comparing balloon borne high-resolution measurements of chemical tracers with reconstructed mixing ratio from large ensembles of random Lagrangian backward trajectories using European Center for Medium-range Weather Forecasts analysed winds and a chemistry-transport model (REPROBUS). We have investigated cases in subtropical latitudes using data from HIBISCUS campaign. Upper bound on the vertical diffusivity is found to be of the order of 0.5 m2 s-1 in the subtropical region, which is larger than the estimates at higher latitudes. The relation between diffusion and dispersion is studied by estimating Lyapunov exponents and studying their variation according to the presence of active dynamical structures.

Pisso, I.; Legras, B.

2007-05-01

111

Turbulent vertical diffusivity in the sub-tropical stratosphere  

NASA Astrophysics Data System (ADS)

Vertical (cross-isentropic) mixing is produced by small-scale turbulent processes which are still poorly understood and paramaterized in numerical models. In this work we provide estimates of local equivalent diffusion in the lower stratosphere by comparing balloon borne high-resolution measurements of chemical tracers with reconstructed mixing ratio from large ensembles of random Lagrangian backward trajectories using European Centre for Medium-range Weather Forecasts analysed winds and a chemistry-transport model (REPROBUS). We focus on a case study in subtropical latitudes using data from HIBISCUS campaign. An upper bound on the vertical diffusivity is found in this case study to be of the order of 0.5 m2 s-1 in the subtropical region, which is larger than the estimates at higher latitudes. The relation between diffusion and dispersion is studied by estimating Lyapunov exponents and studying their variation according to the presence of active dynamical structures.

Pisso, I.; Legras, B.

2008-02-01

112

Vertical combustor for refuse combustion  

SciTech Connect

A vertical combustor for refuse-particle combustion was analyzed for waste-to-energy recovery. A one-dimensional model was constructed that consisted of fuel particles, inert solid particles, and the gaseous mixture. The gaseous mixture was divided further into six chemical species that are involved in combustion at temperatures below about 2000/sup 0/F. It was concluded that such combustors may be viable in the United States since US refuse contains large amounts of volatile matter. Combustion of the relatively small char, however, may not be cost-effective in the present combustor where the fuel residence time is on the order of 2 s for a combustor height of 20 to 30 ft. A computer solution was designed to optimize a given combustor system. A simplified version of the solution was programmed for a TI-59 programmable hand calculator for field use.

Chung, P.M.

1981-06-01

113

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.

2014-03-19

114

Microplasma illumination enhancement of vertically aligned conducting ultrananocrystalline diamond nanorods  

PubMed Central

Vertically aligned conducting ultrananocrystalline diamond (UNCD) nanorods are fabricated using the reactive ion etching method incorporated with nanodiamond particles as mask. High electrical conductivity of 275??·cm?1 is obtained for UNCD nanorods. The microplasma cavities using UNCD nanorods as cathode show enhanced plasma illumination characteristics of low threshold field of 0.21?V/?m with plasma current density of 7.06?mA/cm2 at an applied field of 0.35?V/?m. Such superior electrical properties of UNCD nanorods with high aspect ratio potentially make a significant impact on the diamond-based microplasma display technology. PMID:23009733

2012-01-01

115

Microplasma illumination enhancement of vertically aligned conducting ultrananocrystalline diamond nanorods.  

PubMed

Vertically aligned conducting ultrananocrystalline diamond (UNCD) nanorods are fabricated using the reactive ion etching method incorporated with nanodiamond particles as mask. High electrical conductivity of 275??·cm-1 is obtained for UNCD nanorods. The microplasma cavities using UNCD nanorods as cathode show enhanced plasma illumination characteristics of low threshold field of 0.21?V/?m with plasma current density of 7.06?mA/cm2 at an applied field of 0.35?V/?m. Such superior electrical properties of UNCD nanorods with high aspect ratio potentially make a significant impact on the diamond-based microplasma display technology. PMID:23009733

Sankaran, Kamatchi Jothiramalingam; Kunuku, Srinivasu; Lou, Shiu-Cheng; Kurian, Joji; Chen, Huang-Chin; Lee, Chi-Young; Tai, Nyan-Hwa; Leou, Keh-Chyang; Chen, Chulung; Lin, I-Nan

2012-01-01

116

Vertical velocity-CCN correlations  

NASA Astrophysics Data System (ADS)

The realization that smaller cloud droplets evaporate more readily (Xue and Feingold 2006; Jiang et al. 2002) gives rise to an anti-indirect aerosol effect (IAE); less cloudiness with pollution. The greater latent heat exchange of the greater evaporation in more polluted clouds adds TKE and buoyancy gradients that can enhance vertical velocity (W), mixing and entrainment (Zhao and Austin 2005). Stronger W can increase horizontal motions, which can further enhance droplet evaporation, which further enhances latent heat exchange and vertical motions, thus, positive feedback. This could also include latent heat released during condensation (Lee and Feingold 2010), which is more rapid for the greater surface areas of the smaller more numerous droplets. These theories imply a positive relationship between within-cloud W variations; i.e., standard deviation of W (?w) and CCN concentration (NCCN) rather than W and NCCN. This implies greater turbulence in polluted clouds, which could possibly counteract the reduction of cloudiness of anti-IAE. During two stratus cloud projects, 50 cloud penetrations in 9 MASE flights and 34 cloud penetrations in 13 POST flights, within-cloud ?w-NCCN showed correlation coefficients (R) of 0.50 and 0.39. Panel a shows similar within-cloud ?w-NCCN R in all altitude bands for 17 RICO flights in small cumulus clouds. R for W-NCCN showed similar values but only at low altitudes. Out-of-cloud ?w-NCCN showed similar high values except at the highest altitudes. Within-cloud ?w showed higher R than within-cloud W with droplet concentrations (Nc), especially at higher altitudes. Panel b for 13 ICE-T cumulus cloud flights in the same location as RICO but during the opposite season, however, showed ?w and W uncorrelated with NCCN at all altitudes; and W and ?w correlated with Nc only at the highest altitudes. On the other hand, out-of-cloud ?w was correlated with NCCN at all altitudes with R similar to the corresponding R of the other projects. Overall these results are consistent with the theories noted above. Supported by NSF AGS-1035230 and DOE SC0009162. Jiang, H., G. Feingold, and W.R. Cotton, 2002: J. Geophys. Res, 107, D24, 4813. Lee, S.-S., and G. Feingold, 2010: Geophys. Res. Lett., 37, L23806. Xue, H., and G. Feingold, 2006: J. Atmos. Sci., 63, 1605-1622. Zhao, M., and P.H. Austin, 2005: J. Atmos. Sci., 62, 1291-1310. Fig. Correlation coefficients (R) between mean and standard deviations of vertical velocity (W; ?w within and outside of clouds) with CCN concentrations at 1% supersaturation (N1%) measured below the clouds and with droplet concentrations (Nc) within various altitude bands.

Hudson, J. G.; Noble, S. R.

2013-12-01

117

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

118

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

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

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

121

Vertical two chamber reaction furnace  

DOEpatents

A vertical two chamber reaction furnace is disclosed. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

Blaugher, R.D.

1999-03-16

122

Nitrogen vertical distribution by canopy reflectance spectrum in winter wheat  

NASA Astrophysics Data System (ADS)

Nitrogen is a key factor for plant photosynthesis, ecosystem productivity and leaf respiration. Under the condition of nitrogen deficiency, the crop shows the nitrogen deficiency symptoms in the bottom leaves, while excessive nitrogen will affect the upper layer leaves first. Thus, timely measurement of vertical distribution of foliage nitrogen content is critical for growth diagnosis, crop management and reducing environmental impact. This study presents a method using bi-directional reflectance difference function (BRDF) data to invert foliage nitrogen vertical distribution. We developed upper-layer nitrogen inversion index (ULNI), middle-layer nitrogen inversion index (MLNI) and bottom-layer nitrogen inversion index (BLNI) to reflect foliage nitrogen inversion at upper layer, middle layer and bottom layer, respectively. Both ULNI and MLNI were made by the value of the ratio of Modified Chlorophyll Absorption Ration Index to the second Modified Triangular Vegetation Index (MCARI/MTVI2) referred to as canopy nitrogen inversion index (CNII) in this study at ±40° and ±50°, and at ±30° and ±40° view angles, respectively. The BLNI was composed by the value of nitrogen reflectance index (NRI) at ±20° and ±30° view angles. These results suggest that it is feasible to measure foliage nitrogen vertical-layer distribution in a large scale by remote sensing.

Huang, W. J.; Yang, Q. Y.; Peng, D. L.; Huang, L. S.; Zhang, D. Y.; Yang, G. J.

2014-03-01

123

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

124

INVESTIGATING THERMODYNAMICS OF VERTICAL ATMOSPHERIC ENERGY TRANSPORT  

E-print Network

INVESTIGATING THERMODYNAMICS OF VERTICAL ATMOSPHERIC ENERGY TRANSPORT Wei Wu and Yangang Liu National Laboratory P.O. Box, Upton, NY www.bnl.gov ABSTRACT Thermodynamics of vertical atmospheric energy. Potential thermodynamic constraint(s) for the Earth's climate system are also explored from these simple

125

Downstream Competition, Foreclosure, and Vertical Integration  

E-print Network

Downstream Competition, Foreclosure, and Vertical Integration Gilles Chemla ¤ July 8, 2002 and Management Strategy 12, 2 (2003) 261-289." #12;Downstream Competition, Forclosure, and Vertical Integration Abstract This paper analyzes the impact of competition among downstream ¯rms on an upstream ¯rm's payo

Paris-Sud XI, Université de

126

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

127

Silicon Micromachined Vertical Structures for Nanoparticle Separation  

Microsoft Academic Search

In this thesis we described a new approach to design, fabricate, package and test three silicon based porous vertical structures for nanoparticle separations. These vertical structures stand in between two microfluidic channels. In these walls nano channels that connect the two adjacent microchannels are embedded. Fluid and small particles can penetrate the walls through the embedded nano channels while particles

C. Shen

2011-01-01

128

Natural convection of two staggered cylinders for various prandtl numbers and vertical and horizontal pitches  

NASA Astrophysics Data System (ADS)

Natural convection heat transfer phenomena of two staggered cylinders were investigated for laminar flows. Numerical simulations were carried out to examine the effect of varying the Prandtl number and the vertical and horizontal pitch-to-diameter ratios for a Rayleigh number of 1.5 × 108 using FLUENT. This study focused on phenomena related to very small vertical pitch. The heat transfer rates of the upper cylinders were influenced by plumes from the lower cylinders, exhibiting preheating, velocity, sweep, and side flow effects. The heat transfer rates of the lower cylinders were not affected by the upper cylinders at moderate vertical pitches. However, when the vertical pitch was very small, they were affected by stagnant flow, sweep, and side flow effects.

Heo, Jeong-Hwan; Chung, Bum-Jin

2014-06-01

129

Empirical evaluation of microtremor H\\/V spectral ratio  

Microsoft Academic Search

The objective of this work is to perform a purely empirical assessment of the actual capabilities of the horizontal-to-vertical\\u000a (H\\/V) spectral ratio technique to provide reliable and relevant information concerning site conditions and\\/or site amplification.\\u000a This objective has been tackled through the homogeneous (re)processing of a large volume of earthquakes and ambient noise\\u000a data recorded by different research teams in

E. Haghshenas; P.-Y. Bard; N. Theodulidis

2008-01-01

130

A High Aspect-Ratio Polysilicon Vibrating Ring Gyroscope  

Microsoft Academic Search

Drive and Control This paper presents the fabrication and testing of a high aspect-ratio 80um tall polysilicon ring gyroscope (PRG) fabricated using a new dry-release poly-silicon MEMS technology. This single-wafer technology is capable of producing electrically isolated vertical electrodes as tall as the main body polysilicon structure (50 to 100's urn tall) with various size air-gaps ranging from sub-micron to

Farrokh Ayazi; Hsiao H. Chen; Fatih Kocer; Guohong He; Khalil Najafl

2000-01-01

131

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

132

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

2014-09-09

133

A vertical axis cyclogiro type wind-turbine with freely-hinged blades  

NASA Astrophysics Data System (ADS)

A description is given of the design, construction and testing of a prototype vertical axis cycloturbine. The machine has straight vertical blades of symmetrical cross-section. Each blade is hinged, on a vertical axis, near its upper and lower extremities to the ends of radial arms projecting from a central, rotating, tower structure. What is believed to be a unique method is used for the control of blade articulation. The cyclic motion of each blade is derived solely from a combination of the centrifuging action of a mass attached to the blade and the aerodynamic load acting on the blade. Results of open-air tests of the small two-bladed prototype unit resulted in the achievement of a maximum power coefficient of 0.37 at a velocity ratio of 3.6 with a runaway velocity ratio of 5.2. The machine was found to self-start easily.

Bayly, D. A.; Kentfield, J. A. C.

134

Reversal of optic disc cupping with improvement of visual field and stereometric parameters after trabeculectomy in young adult patients (two case reports).  

PubMed

The authors report two cases of mid- to long-term reversal of optic disc cupping after trabeculectomy with mitomycine-C in young adult patients suffering from secondary glaucoma. The cup to disc ratio reversed from 0.80 and 0.60 to 0.65 and 0.40 respectively and remained unchanged until the last follow-up visit at 6 and 36 months respectively. Concomitantly, there was an improvement of the visual field and of the optic disc stereometric parameters on the Heidelberg Retina Tomograph. PMID:21305812

Swinnen, S; Stalmans, I; Stalmans, A; Zeyen, T

2010-01-01

135

A Numerical Study of the Vertical Round Jets in Cross-flows  

Microsoft Academic Search

A numerical study of the vertical round jets in cross-flows using the standard k-epsilo turbulence model is presented. The computational jet trajectories agree well with experimental data and theoretical results. We have acquired the jet trajectories at different jet ratios and their unified expression, the unified expressions of the inner and outer boundaries of the jet influence domain on the

Xiaoyuan Zhang; Changcheng Li

2010-01-01

136

Coriolis Effect on Dynamic Stall in a Vertical Axis Wind Turbine at Moderate Reynolds Number  

E-print Network

Coriolis Effect on Dynamic Stall in a Vertical Axis Wind Turbine at Moderate Reynolds Number Hsieh. The influence of dynamic stall on the forces is characterized as a function of tip-speed ratio. The influence generation. Dynamic stall refers to the delay in the stall of airfoils that are rapidly pitched beyond

Colonius, Tim

137

Modeling multifrequency eddy current sensor interactions during vertical Bridgman growth of semiconductors  

E-print Network

Modeling multifrequency eddy current sensor interactions during vertical Bridgman growth methods have been used to analyze the responses of two ``absolute'' and ``differential'' eddy current conductivity ratio increases. Of the materials studied, GaAs is found best suited for eddy current sensing

Wadley, Haydn

138

Silicon Carbide Epitaxy in a Vertical CVD Reactor: Experimental Results and Numerical Process Simulation  

Microsoft Academic Search

In this paper an overview is given on the epitaxial growth of SiC in a vertical CVD reactor. Results concerning impurity incorporation and ways to achieve background doping levels as low as 1014 cm - 3 are discussed. Precise control of the C\\/Si ratio in the gas phase, which is easily achieved in the described reactor, and the use of

R. Rupp; Yu. N. Makarov; H. Behner; A. Wiedenhofer

1997-01-01

139

Energy Profit Ratio Compared  

SciTech Connect

We need more oil energy to take out oil under the ground. Limit resources make us consider other candidates of energy source instead of oil. Electricity shall be the main role more and more like electric vehicles and air conditioners so we should consider electricity generation ways. When we consider what kind of electric power generation is the best or suitable, we should not only power generation plant but whole process from mining to power generation. It is good way to use EPR, Energy Profit Ratio, to analysis which type is more efficient and which part is to do research and development when you see the input breakdown analysis. Electricity by the light water nuclear power plant, the hydrogen power plant and the geothermal power plant are better candidates from EPR analysis. Forecasting the world primly energy supply in 2050, it is said that the demand will be double of the demand in 2000 and the supply will not be able to satisfy the demand in 2050. We should save 30% of the demand and increase nuclear power plants 3.5 times more and recyclable energy like hydropower plants 3 times more. When the nuclear power plants are 3.5 times more then uranium peak will come and we will need breed uranium. I will analysis the EPR of FBR. Conclusion: A) the EPR of NPS in Japan is 17.4 and it is the best of all. B) Many countries will introduce new nuclear power plants rapidly may be 3.5 times in 2050. C) Uranium peak will happen around 2050. (author)

Amano, Osamu [2-11-1, Iwado Kita, Komae-shi, Tokyo 201-8511 (Japan)

2007-07-01

140

ITER physics design guidelines at high aspect ratio  

NASA Astrophysics Data System (ADS)

The physics requirements for the International Thermonuclear Experimental Reactor (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 is approximately 20 MA and aspect ratio A is approximately 2.5--3.5) that meet the ITER objectives. Recent U.S. 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 Ais approximately 4, I is 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 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.

Uckan, N. A.

1991-09-01

141

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

142

Climatic significance of isotope ratios  

Microsoft Academic Search

The hydrogen and oxygen isotope ratios of water, which can be measured by Isotope Ratio Mass Spectrometry (IRMS), exhibit climatic dependencies and are commonly exploited in hydrogeology. More generally, the overall carbon or hydrogen isotope ratios of plant organic matter, and in particular of tree-ring cellulose, have been frequently used for climatic reconstruction. However, since many physicochemical and biochemical fractionation

Gérard J. Martin; Maryvonne L. Martin

2003-01-01

143

Poisson's ratio and crustal seismology  

Microsoft Academic Search

New measurements of compressional and shear wave velocities to hydrostatic pressures of 1 GPa are summarized for 678 rocks. Emphasis was placed on obtaining high-accuracy velocity measurements, which are shown to be critical in calculating Poisson's ratios from velocities. The rocks have been divided into 29 major groups for which velocities, velocity ratios, and Poisson's ratios are presented at several

Nikolas I. Christensen

1996-01-01

144

Surface tension profiles in vertical soap films  

NASA Astrophysics Data System (ADS)

Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed by introducing deformable elastic objets in the films. The shape adopted by those objects once set in the film is related to the surface tension value at a given vertical position by numerically solving the adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position is predicted by simple modeling that takes into account the mechanical equilibrium of the films coupled to previous thickness measurements.

Adami, N.; Caps, H.

2015-01-01

145

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

146

Vertically stacked multi-heterostructures of layered materials for logic transistors and complementary inverters  

NASA Astrophysics Data System (ADS)

Graphene has attracted considerable interest for future electronics, but the absence of a bandgap limits its direct applicability in transistors and logic devices. Recently, other layered materials such as molybdenum disulphide (MoS2) have been investigated to address this challenge. Here, we report the vertical integration of multi-heterostructures of layered materials for the fabrication of a new generation of vertical field-effect transistors (VFETs) with a room temperature on-off ratio > 103 and a high current density of up to 5,000?A?cm-2. An n-channel VFET is created by sandwiching few-layer MoS2 as the semiconducting channel between a monolayer graphene sheet and a metal thin film. This approach offers a general strategy for the vertical integration of p- and n-channel transistors for high-performance logic applications. As an example, we demonstrate a complementary inverter with a larger-than-unity voltage gain by vertically stacking graphene, Bi2Sr2Co2O8 (p-channel), graphene, MoS2 (n-channel) and a metal thin film in sequence. The ability to simultaneously achieve a high on-off ratio, a high current density and a logic function in such vertically stacked multi-heterostructures can open up possibilities for three-dimensional integration in future electronics.

Yu, Woo Jong; Li, Zheng; Zhou, Hailong; Chen, Yu; Wang, Yang; Huang, Yu; Duan, Xiangfeng

2013-03-01

147

Vertically stacked multi-heterostructures of layered materials for logic transistors and complementary inverters.  

PubMed

Graphene has attracted considerable interest for future electronics, but the absence of a bandgap limits its direct applicability in transistors and logic devices. Recently, other layered materials such as molybdenum disulphide (MoS(2)) have been investigated to address this challenge. Here, we report the vertical integration of multi-heterostructures of layered materials for the fabrication of a new generation of vertical field-effect transistors (VFETs) with a room temperature on-off ratio > 10(3) and a high current density of up to 5,000 A cm(-2). An n-channel VFET is created by sandwiching few-layer MoS(2) as the semiconducting channel between a monolayer graphene sheet and a metal thin film. This approach offers a general strategy for the vertical integration of p- and n-channel transistors for high-performance logic applications. As an example, we demonstrate a complementary inverter with a larger-than-unity voltage gain by vertically stacking graphene, Bi(2)Sr(2)Co(2)O(8) (p-channel), graphene, MoS(2) (n-channel) and a metal thin film in sequence. The ability to simultaneously achieve a high on-off ratio, a high current density and a logic function in such vertically stacked multi-heterostructures can open up possibilities for three-dimensional integration in future electronics. PMID:23241535

Yu, Woo Jong; Li, Zheng; Zhou, Hailong; Chen, Yu; Wang, Yang; Huang, Yu; Duan, Xiangfeng

2013-03-01

148

Subsurface imaging with reverse vertical seismic profiles  

E-print Network

This thesis presents imaging results from a 3D reverse vertical seismic profile (RVSP) dataset measured at a hydrocarbon bearing pinnacle reef in northern Michigan. The study presented many challenges in seismic data ...

Krasovec, Mary L. (Mary Lee), 1972-

2001-01-01

149

Stability of Granular Materials under Vertical Vibrations  

E-print Network

The influence of periodic vibrations on the granular flow of materials is of great interests to scientists and engineers due to both theoretical and practical reasons. In this paper, the stability of a vertically vibrated ...

Deng, Rensheng

150

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.

151

Vertical Axis Wind Turbine Foundation parameter study  

SciTech Connect

The dynamic failure criterion governing the dimensions of prototype Vertical Axis Wind Turbine Foundations is treated as a variable parameter. The resulting change in foundation dimensions and costs is examined.

Lodde, P.F.

1980-07-01

152

Vertical Glider Robots for Subsea Equipment Delivery  

E-print Network

We have developed an underwater vehicle that offers significant performance improvements over existing sub sea elevators. Our Vertical Glider Robot falls under its own weight to a precise location on the seafloor, employing ...

Reed, Brooks L.

2011-01-01

153

Vertical axis wind turbine foundation parameter study  

NASA Astrophysics Data System (ADS)

The foundation/anchor requirements for the Vertical Axis Wind Turbine are identified. Information is supplied concerning the selection, design, and cost estimates for the geologic conditions which may be encountered at potential wind turbine sites.

Ludde, P. F.

1980-07-01

154

Vertical Discretization in Tidal Flow Simulations  

NASA Astrophysics Data System (ADS)

We propose an empirical law for vertical nodal placement in tidal simulations that depends on a single parameter p. The influence of dimensionless numbers on the optimal value of p is analysed through a series of numerical experiments for an individual vertical and a single value of p is found to be adequate for all cases. The proposed law can lead to gains in accuracy of over two orders of magnitude relative to a uniform grid and compares favourably with non-uniform grids previously used in the literature. In practical applications the most effective use of this law may require each vertical to have a different number of nodes. Criteria for the distribution of the total number of nodes among different verticals are also proposed, based on the concept of equalizing errors across the domain. The usefulness of the overall approach is demonstrated through a two-dimensional laterally averaged application to a synthetic estuary.

Fortunato, André B.; Baptista, António M.

1996-05-01

155

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

156

Vertical Motions of Oceanic Volcanoes  

NASA Astrophysics Data System (ADS)

Oceanic volcanoes offer abundant evidence of changes in their elevations through time. Their large-scale motions begin with a period of rapid subsidence lasting hundreds of thousands of years caused by isostatic compensation of the added mass of the volcano on the ocean lithosphere. The response is within thousands of years and lasts as long as the active volcano keeps adding mass on the ocean floor. Downward flexure caused by volcanic loading creates troughs around the growing volcanoes that eventually fill with sediment. Seismic surveys show that the overall depression of the old ocean floor beneath Hawaiian volcanoes such as Mauna Loa is about 10 km. This gross subsidence means that the drowned shorelines only record a small part of the total subsidence the islands experienced. In Hawaii, this history is recorded by long-term tide-gauge data, the depth in drill holes of subaerial lava flows and soil horizons, former shorelines presently located below sea level. Offshore Hawaii, a series of at least 7 drowned reefs and terraces record subsidence of about 1325 m during the last half million years. Older sequences of drowned reefs and terraces define the early rapid phase of subsidence of Maui, Molokai, Lanai, Oahu, Kauai, and Niihau. Volcanic islands, such as Maui, tip down toward the next younger volcano as it begins rapid growth and subsidence. Such tipping results in drowned reefs on Haleakala as deep as 2400 m where they are tipped towards Hawaii. Flat-topped volcanoes on submarine rift zones also record this tipping towards the next younger volcano. This early rapid subsidence phase is followed by a period of slow subsidence lasting for millions of years caused by thermal contraction of the aging ocean lithosphere beneath the volcano. The well-known evolution along the Hawaiian chain from high to low volcanic island, to coral island, and to guyot is due to this process. This history of rapid and then slow subsidence is interrupted by a period of minor uplift lasting a few hundred thousand years as the island migrates over a broad flexural arch related to isostatic compensation of a nearby active volcano. The arch is located about 190±30 km away from the center of volcanic activity and is also related to the rejuvenated volcanic stage on the islands. Reefs on Oahu that are uplifted several tens of m above sea level are the primary evidence for uplift as the islands over-ride the flexural arch. At the other end of the movement spectrum, both in terms of magnitude and length of response, are the rapid uplift and subsidence that occurs as magma is accumulated within or erupted from active submarine volcanoes. These changes are measured in days to years and are of cm to m variation; they are measured using leveling surveys, tiltmeters, EDM and GPS above sea level and pressure gauges and tiltmeters below sea level. Other acoustic techniques to measure such vertical movement are under development. Elsewhere, evidence for subsidence of volcanoes is also widespread, ranging from shallow water carbonates on drowned Cretaceous guyots, to mapped shoreline features, to the presence of subaerially-erupted (degassed) lavas on now submerged volcanoes. Evidence for uplift is more limited, but includes makatea islands with uplifted coral reefs surrounding low volcanic islands. These are formed due to flexural uplift associated with isostatic loading of nearby islands or seamounts. In sum, oceanic volcanoes display a long history of subsidence, rapid at first and then slow, sometimes punctuated by brief periods of uplift due to lithospheric loading by subsequently formed nearby volcanoes.

Clague, D. A.; Moore, J. G.

2006-12-01

157

Magellan vertical polarization radar observations  

NASA Technical Reports Server (NTRS)

The Magellan high-gain radar antenna system was designed to transmit and receive signals in a pure linear polarization state. The nominal mapping configuration placed this linear polarization direction parallel to the surface of Venus, providing SAR image data in the HH polarization (horizontal transmit and receive) and radiothermal emission data in the H (horizontal - receive only) polarization. During Magellan's extended mission (cycles 2 and 3), two brief experiments were conducted in which the spacecraft was rotated 90 degrees along the axis of the antenna boresight, producing SAR data in the VV polarization and emission data in the V polarization. This study focuses on the SAR results from the first experiment, which included portions of the highly reflective Beta Regio highlands. Theoretical models of polarimetric backscatter, along with experimental data from terrestrial surfaces, predict VV backscatter cross section values to be higher than HH values for most natural surfaces. Randomly polarized ('depolarized') backscatter from rough surfaces is expected in equal amounts for either incident polarization. Roughness differences will therefore be more pronounced in HH measurements than in VV, because the depolarized random component makes up a proportionately larger fraction of the HH backscatter. In addition, HH cross section values are observed to fall off more rapidly than VV values with increasing incidence angle. Slope-related backscatter differences will, therefore, be more pronounced in HH images. The small perturbation polarimetric scattering model also predicts higher VV to HH ratios for surfaces of high dielectric constant.

Plaut, Jeffrey J.

1993-01-01

158

Effect of vertical motion on current meters  

USGS Publications Warehouse

The effect of vertical motion on the performance of current meters at various stream velocities was evaluated to determine whether accurate discharge measurements can be made from a bobbing boat. Three types of current meters--Ott, Price, and vane types--were tested under conditions simulating a bobbing boat. A known frequency and amplitude of vertical motion were imparted to the current meter, and the related effect on the measured stream velocity was determined. One test of the Price meter was made under actual conditions, using a boat and standard measuring gear. The results of the test under actual conditions verified those obtained by simulating the vertical movements of a boat. The tests show that for stream velocities below 2.5 feet per second the accuracy of all three meters is significantly affected when the meters are subjected to certain conditions of vertical motion that can occur during actual field operations. Both the rate of vertical motion and the frequency of vertical oscillation affect the registration of the meter. The results of these tests, presented in the form of graphs and tables, can be used as a guide to determine whether wind and stream flow are within an acceptable range for a reliable discharge measurement from a boat.

Kallio, Nicholas A.

1966-01-01

159

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

160

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

161

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

162

Vertical distribution of (241)Pu in the southern Baltic Sea sediments.  

PubMed

The vertical distribution of plutonium (241)Pu in marine sediments can assist in determining the deposition history and sedimentation process of analyzed regions. In addition, (241)Pu/(239+240)Pu activity ratio could be used as a sensitive fingerprint for radioactive source identification. The present preliminary studies on vertical distribution of (241)Pu in sediments from four regions of the southern Baltic Sea are presented. The distribution of (241)Pu was not uniform and depended on sediment geomorphology and depth as well as location. The highest concentrations of plutonium were found in the surface layers of all analyzed sediments and originated from the Chernobyl accident. PMID:25455816

Strumi?ska-Parulska, Dagmara I

2014-12-15

163

Characteristics of the bovine claw associated with the presence of vertical fissures (sandcracks)  

PubMed Central

Abstract Vertical fissures (sandcracks) affect approximately 20% of adult beef cattle in western Canada. The risk factors associated with the formation of these lesions are not well understood. This paper describes a case-control study that identifies the role of increased claw size (claw volume >390 cm3, odds ratio 7.8) in the formation of the lesion. No connection was found between vertical fissures and horn hydration status. However, horn hydration was found to vary significantly between samples collected in the summer and winter, the latter samples having significantly reduced moisture content. The importance of these findings and the implications for the prevention of fissure formation are discussed. PMID:15317390

2004-01-01

164

Adjusting Intraocular Pressure for Central Corneal Thickness Does Not Improve Prediction Models for Primary Open-Angle Glaucoma  

PubMed Central

Purpose To determine if the accuracy of the baseline prediction model for the development of primary open-angle glaucoma (POAG) in ocular hypertension patients can be improved by correcting intraocular pressure (IOP) for central corneal thickness (CCT). Design Re-analysis of the baseline prediction model for the development of POAG from the Ocular Hypertension Treatment Study (OHTS) substituting IOP adjusted for CCT using 5 different correction formulae for unadjusted IOP. Participants 1,433 of 1,636 participants randomized to OHTS who had complete baseline data for factors in the prediction model – age, IOP, CCT, vertical cup-to-disc ratio (VCDR) and pattern standard deviation (PSD). Methods Re-analysis of the prediction model for the risk of developing POAG using the same baseline variables (age, IOP, CCT, VCDR and PSD) except that IOP was adjusted for CCT using correction formulae. A separate Cox proportional hazards model was run using IOP adjusted for CCT by each of the five formulae published to date. Models were run including and excluding CCT. Main Outcome Measures Predictive accuracy of each Cox proportional hazards model was assessed using the c-statistic and calibration chi-square. Results C-statistics for prediction models that used IOP adjusted for CCT by various formulas ranged from 0.75 to 0.77, no better than the original prediction model (0.77) that did not adjust IOP for CCT. Calibration chi-square was acceptable for all models. Baseline IOP, whether adjusted for CCT or not, was statistically significant in all models including those with CCT in the same model. CCT was statistically significant in all models including those with IOP adjusted for CCT in the same model. Conclusion The calculation of individual risk for developing POAG in ocular hypertensive individuals is simpler and equally accurate using IOP and CCT as measured, rather than applying an adjustment formula to correct IOP for CCT. PMID:21705084

Brandt, James D.; Gordon, Mae O.; Gao, Feng; Beiser, Julia A.; Miller, J. Phillip; Kass, Michael A.

2011-01-01

165

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

166

Measuring in situ vertical hydraulic conductivity in tidal environments  

NASA Astrophysics Data System (ADS)

The hydraulic conductivity of intertidal sediments plays an important role in quantifying seawater-groundwater interactions. However, its accurate and economical in situ evaluation is difficult since available in situ methods do not apply in intertidal zones due to periodic tidal fluctuations. Here a new apparatus is presented for measuring the sediments' vertical hydraulic conductivity in tidal environments and a simple, finite-difference data analysis method is proposed to estimate this key parameter. The new apparatus is easy to operate, and is able to measure in situ vertical hydraulic conductivity ranging from 10-7 m/s to 10-2 m/s in tidal environments within one hour. A posteriori error of the finite-difference approximation method is estimated to have the same magnitude order as the square of the nondimensionalized observation time interval K?t/(LV) (here ?t is the observation time interval, Rd is the diameter ratio of the falling-head water-container standpipe to the undisturbed in situ sediment sample, K is the vertical hydraulic conductivity, and LV is the sample length), which is usually a very small number. The new apparatus and finite-difference method were verified by numerical simulations and many in situ experiments in several coastal case study sites of Bohai Sea, PR China. The finite-difference method has adequate accuracy in estimating the hydraulic conductivity compared with the traditional least-squares fitting method. The relative error between the estimates by the two methods is less than 9.41% and averages 1.22% for all experiments. The new apparatus and simple finite-difference method are recommended for in situ experiment that have many advantages such as economy, efficiency, reliability, and simplicity.

Wang, Xuejing; Li, Hailong; Yang, Jinzhi; Wan, Li; Wang, Xusheng; Jiang, Xiaowei; Guo, Huaming

2014-08-01

167

Vertical profiles of nitrous acid in the nocturnal urban atmosphere of Houston, TX  

NASA Astrophysics Data System (ADS)

Nitrous acid (HONO) often plays an important role in tropospheric photochemistry as a major precursor of the hydroxyl radical (OH) in early morning hours and potentially during the day. However, the processes leading to formation of HONO and its vertical distribution at night, which can have a considerable impact on daytime ozone formation, are currently poorly characterized by observations and models. Long-path differential optical absorption spectroscopy (LP-DOAS) measurements of HONO during the 2006 TexAQS II Radical and Aerosol Measurement Project (TRAMP), near downtown Houston, TX, show nocturnal vertical profiles of HONO, with mixing ratios of up to 2.2 ppb near the surface and below 100 ppt aloft. Three nighttime periods of HONO, NO2 and O3 observations during TRAMP were used to perform model simulations of vertical mixing ratio profiles. By adjusting vertical mixing and NOx emissions the modeled NO2 and O3 mixing ratios showed very good agreement with the observations. Using a simple conversion of NO2 to HONO on the ground, direct HONO emissions, as well as HONO loss at the ground and on aerosol, the observed HONO profiles were reproduced well by the model. The unobserved increase of HONO to NO2 ratio (HONO/NO2) with altitude that was simulated by the initial model runs was found to be due to HONO uptake being too small on aerosol and too large on the ground. Refined model runs, with adjusted HONO uptake coefficients, showed much better agreement of HONO and HONO/NO2 for two typical nights, except during morning rush hour, when other HONO formation pathways are most likely active. One of the nights analyzed showed increase of HONO mixing ratios together with decreasing NO2 mixing ratios that the model was unable to reproduce, most likely due to the impact of weak precipitation during this night. HONO formation and removal rates averaged over the lowest 300 m of the atmosphere showed that NO2 to HONO conversion on the ground was the dominant source of HONO, followed by traffic emission. Aerosol did not play an important role in HONO formation. Although ground deposition was also a major removal pathway of HONO, net HONO production at the ground was the main source of HONO in our model studies. Sensitivity studies showed that in the stable NBL, net HONO production at the ground tends to increase with faster vertical mixing and stronger emission. Vertical transport was found to be the dominant source of HONO aloft.

Wong, K. W.; Oh, H.-J.; Lefer, B.; Rappenglück, B.; Stutz, J.

2010-12-01

168

Vertical profiles of nitrous acid in the nocturnal urban atmosphere of Houston, TX  

NASA Astrophysics Data System (ADS)

Nitrous acid (HONO) often plays an important role in tropospheric photochemistry as a major precursor of the hydroxyl radical (OH) in early morning hours and potentially during the day. However, the processes leading to formation of HONO and its vertical distribution at night, which can have a considerable impact on daytime ozone formation, are currently poorly characterized by observations and models. Long-path differential optical absorption spectroscopy (LP-DOAS) measurements of HONO during the 2006 TexAQS II Radical and Aerosol Measurement Project (TRAMP), near downtown Houston, TX, show nocturnal vertical profiles of HONO, with mixing ratios of up to 2.2 ppb near the surface and below 100 ppt aloft. Three nighttime periods of HONO, NO2 and O3 observations during TRAMP were used to perform model simulations of vertical mixing ratio profiles. By adjusting vertical mixing and NOx emissions the modeled NO2 and O3 mixing ratios showed very good agreement with the observations. Using a simple conversion of NO2 to HONO on the ground, direct HONO emissions, as well as HONO loss at the ground and on aerosol, the observed HONO profiles were reproduced by the model for 1-2 and 7-8 September in the nocturnal boundary layer (NBL). The unobserved increase of HONO to NO2 ratio (HONO/NO2) with altitude that was simulated by the initial model runs was found to be due to HONO uptake being too small on aerosol and too large on the ground. Refined model runs, with adjusted HONO uptake coefficients, showed much better agreement of HONO and HONO/NO2 for two typical nights, except during morning rush hour, when other HONO formation pathways are most likely active. One of the nights analyzed showed an increase of HONO mixing ratios together with decreasing NO2 mixing ratios that the model was unable to reproduce, most likely due to the impact of weak precipitation during this night. HONO formation and removal rates averaged over the lowest 300 m of the atmosphere showed that NO2 to HONO conversion on the ground was the dominant source of HONO, followed by traffic emission. Aerosol did not play an important role in HONO formation. Although ground deposition was also a major removal pathway of HONO, net HONO production at the ground was the main source of HONO in our model studies. Sensitivity studies showed that in the stable NBL, net HONO production at the ground tends to increase with faster vertical mixing and stronger NOx emission. Vertical transport was found to be the dominant source of HONO aloft.

Wong, K. W.; Oh, H.-J.; Lefer, B. L.; Rappenglück, B.; Stutz, J.

2011-04-01

169

Waferbonded active/passive vertically coupled microring lasers  

NASA Astrophysics Data System (ADS)

We summarize the results of a European Project entitled WAPITI (Waferbonding and Active Passive Integration Technology and Implementation) dealing with the fabrication and investigation of active/passive vertically coupled ring resonators, wafer bonded on GaAs, and based on full wafer technology. The concept allows for the integration of an active ring laser vertically coupled to a transparent bus waveguide. All necessary layers are grown in a single epitaxial run so that the critical coupling gap can be precisely controlled with the high degree of accuracy of epitaxial growth. One key challenge of the project was to establish a reliable wafer bonding technique using BCB as an intermediate layer. In intensive tests we investigated and quantified the effect of unavoidable shrinkage of the BCB on the overall device performance. Results on cw-operation, low threshold currents of about 8 mA, high side-mode suppression ratios in the range of 40 dB and large signal modulation bandwidths of up to 5 GHz for a radius of 40 ?m shows the viability of the integration process.

Hamacher, M.; Heidrich, H.; Troppenz, U.; Syvridis, D.; Alexandropoulos, D.; Mikroulis, S.; Kapsalis, A.; Tee, C. W.; Williams, K.; Dragoi, V.; Alexe, M.; Cristea, D.; Kusko, M.

2008-02-01

170

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

Microsoft Academic Search

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

1988-01-01

171

Adhesion of biologically inspired vertical and angled polymer microfiber arrays.  

PubMed

This paper proposes an approximate adhesion model for fibrillar adhesives for developing a fibrillar adhesive design methodology and compares numerical simulation adhesion results with macroscale adhesion data from polymer microfiber array experiments. A technique for fabricating microfibers with a controlled angle is described for the first time. Polyurethane microfibers with different hardnesses, angles, and aspect ratios are fabricated using optical lithography and polymer micromolding techniques and tested with a custom tensile adhesion measurement setup. Macroscale adhesion and overall work of adhesion of the microfiber arrays are measured and compared with the models to observe the effect of fiber geometry and preload. The adhesion strength and work of adhesion behavior of short and long vertical and long angled fiber arrays have similar trends with the numerical simulations. A scheme is also proposed to aid in optimized fiber adhesive design. PMID:17284057

Aksak, Burak; Murphy, Michael P; Sitti, Metin

2007-03-13

172

Field-effect tunneling transistor based on vertical graphene heterostructures.  

PubMed

An obstacle to the use of graphene as an alternative to silicon electronics has been the absence of an energy gap between its conduction and valence bands, which makes it difficult to achieve low power dissipation in the OFF state. We report a bipolar field-effect transistor that exploits the low density of states in graphene and its one-atomic-layer thickness. Our prototype devices are graphene heterostructures with atomically thin boron nitride or molybdenum disulfide acting as a vertical transport barrier. They exhibit room-temperature switching ratios of ?50 and ?10,000, respectively. Such devices have potential for high-frequency operation and large-scale integration. PMID:22300848

Britnell, L; Gorbachev, R V; Jalil, R; Belle, B D; Schedin, F; Mishchenko, A; Georgiou, T; Katsnelson, M I; Eaves, L; Morozov, S V; Peres, N M R; Leist, J; Geim, A K; Novoselov, K S; Ponomarenko, L A

2012-02-24

173

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

174

Vertical seismic profiling on the sea shelf  

NASA Astrophysics Data System (ADS)

Results of a numerical experiment on vertical seismic profiling of the sea bottom on the shelf are presented. The results are obtained by analyzing the acoustic fields in the shelf area with the use of both hydroacoustic and seismic bottom sources of radiation. The influence of both transmission depth and source type on the efficiency of seismic wave excitation in the bottom is investigated. The formation of the vertical wave hodographs and its dependence on the acoustic parameters and structure of the bottom in the oceanic shelf region is analyzed. A high sensitivity of the vertical wave hodographs to variations in the parameters of the bottom medium is revealed. For the layered bottom model, the possibility of estimating the positions of layer boundaries in depth and the velocities of waves within the layers is demonstrated.

Zaslavski?, Yu. M.; Kerzhakov, B. V.; Kulinich, V. V.

2008-05-01

175

Vertical vibration analysis for elevator compensating sheave  

NASA Astrophysics Data System (ADS)

Most elevators applied to tall buildings include compensating ropes to satisfy the balanced rope tension between the car and the counter weight. The compensating ropes receive tension by the compensating sheave, which is installed at the bottom space of the elevator shaft. The compensating sheave is only suspended by the compensating ropes, therefore, the sheave can move vertically while the car is traveling. This paper shows the elevator dynamic model to evaluate the vertical motion of the compensating sheave. Especially, behavior in emergency cases, such as brake activation and buffer strike, was investigated to evaluate the maximum upward motion of the sheave. The simulation results were validated by experiments and the most influenced factor for the sheave vertical motion was clarified.

Watanabe, Seiji; Okawa, Takeya; Nakazawa, Daisuke; Fukui, Daiki

2013-07-01

176

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

177

On the impact of forced roll convection on vertical turbulent transport in cold air outbreaks  

NASA Astrophysics Data System (ADS)

We investigated the impact of roll convection on the convective boundary layer and vertical transports in different cold air outbreak (CAO) scenarios using large eddy simulations (LES). The organization of convection into rolls was triggered by upstream heterogeneities in the surface temperature, representing ice and water. By changing the sea ice distribution in our LES, we were able to simulate a roll and a nonroll case for each scenario. Furthermore, the roll wavelength was varied by changing the scale of the heterogeneity. The characteristics of the simulated rolls and cloud streets, such as aspect ratios, orientation of the roll axes, and downstream extensions of single rolls agreed closely with observations in CAO situations. The vertical turbulent fluxes, calculated for each simulation, were decomposed into contributions from rolls and from unorganized turbulence. Even though our results confirmed that rolls triggered by upstream heterogeneities can substantially contribute to vertical turbulent fluxes, the total fluxes were not affected by the rolls.

Gryschka, Micha; Fricke, Jens; Raasch, Siegfried

2014-11-01

178

Coupling Correction and Beam Dynamics at Ultralow Vertical Emittance in the ALS  

SciTech Connect

For synchrotron light sources and for damping rings of linear colliders it is important to be able to minimize the vertical emittance and to correct the spurious vertical dispersion. This allows one to maximize the brightness and/or the luminosity. A commonly used tool to measure the skew error distribution is the analysis of orbit response matrices using codes like LOCO. Using the new Matlab version of LOCO and 18 newly installed power supplies for individual skew quadrupoles at the ALS the emittance ratio could be reduced below 0.1% at 1.9 GeV yielding a vertical emittance of about 5 pm. At those very low emittances, additional effects like intra beam scattering become more important, potentially limiting the minimum emittance for machine like the damping rings of linear colliders.

Steier, Christoph; Robin, D.; Wolski, A.; Portmann, G.; Safranek, J.; /LBL, Berkeley /SLAC

2008-03-17

179

The fluid mechanics of a high aspect ratio slot with an impressed pressure gradient and secondary injection  

Microsoft Academic Search

A high aspect ratio slot flow (which emulates the gas leakage path in a gas turbine engine outer turbine air seal) is studied by use of a high aspect ratio slot using water as the working fluid. The cross section of the geometry is similar to a 'T', the slot being the vertical stroke and the main flow being the

John Bertram Sobanik

1993-01-01

180

On the measurement of vertical velocity by MST radar  

NASA Technical Reports Server (NTRS)

An overview is presented of the measurement of atmospheric vertical motion utilizing the MST radar technique. Vertical motion in the atmosphere is briefly discussed as a function of scale. Vertical velocity measurement by MST radars is then considered from within the context of the expected magnitudes to be observed. Examples are drawn from published vertical velocity observations.

Gage, K. S.

1983-01-01

181

Combined high density solar panels and vertical wind turbines  

Microsoft Academic Search

The combined high density solar panels and vertical wind turbines consist of multiple solar panels with closely spaced solar cells on both sides which are supported by an open framework and vertical posts. The adoption of an elevated, rooftop solar panel array, supported by vertical posts makes the basic structure attractive for the inclusion of multiple vertical wind turbines, as

1978-01-01

182

European Vertical Datum: Unification within Geopotential Space  

NASA Astrophysics Data System (ADS)

Various local vertical datums, as realised for particular countries or even regions, are in use around the world. These datums were typically established from sea level observations at single or multiple tide gauges. The fundamental geodetic parameter, W0, which represents the geopotential value at the geoid surface, can be used to unify vertical datums within geopotential space. This requires geodetic coordinates of points at mean sea level (MSL), a high resolution geopotential model and an accurate mean dynamic topography (MDT) model. In this study, the UK, German and French datums are unified within geopotential space. The tide gauge time series and co-located GPS provide the tools to connect mean sea level to the Earth's centre of mass. A mean dynamic topography model enables the reduction of MSL to the geoid surface. Referencing the geodetic coordinates of the geoid to an Earth's gravity field model yields a geopotential value which corresponds to the geoid at the TG sites which can then be used to connect the vertical datums in different regions. This study also illustrates the improvement of EGM2008 compared with EGM96 and demonstrates the influence of omission error on our work. Furthermore, to connect regional vertical datums to a world height system, W0 is estimated globally from an altimetry-based global MSL model, a global MDT and EGM2008. Our results show that, at current accuracy of GPS and TG observations and processing strategies, unification of vertical datums is mainly influenced by the accuracy of the geopotential model and MDT. Keywords: Geopotential, EGM2008, vertical datum, MDT

Dayoub, Nadim; Moore, Philip; Edwards, Stuart; Penna, Nigel

2010-05-01

183

Vortex Formation in Vertically Stratified Protoplanetary Disks  

NASA Astrophysics Data System (ADS)

A central problem of planet formation is how to form large planetesimals in a turbulent protoplanetary disk. Recent work suggests that MRI turbulence would excite such large velocities that the planetesimals would collisionally fragment rather than grow. The structure of chondritic meteorites indicates a gentle nebular environment where chondrules are sorted by size and cemented together rapidly. Although it is well established that anticyclones can concentrate particles that are weakly coupled to the gas in protoplanetary disks, the conditions required for the formation and long-time stability of anticyclones in a vertically stratified disk are still highly uncertain. Fully three dimensional fluid dynamic simulations of protoplanetary disks are computationally expensive when one requires a computational domain that is large compared to the vertical scale height of the disk. An alternative simulation approach is to use potential temperature as the vertical coordinate so that the equations of motion resemble the shallow water equations (Dowling et al. 1998). We have therefore modified a multilayer shallow water simulation code to model the formation of vortices in a vertically stratified protoplanetary disk with a radial entropy gradient. Vertical stratification of the disk is modeled by using multiple layers, where each layer has a different constant value of the entropy. By forcing a slope in the interfaces between the layers, we impose a radial entropy gradient in the disk. Radiative heating and cooling causes vertical mass exchange between adjacent constant entropy layers according to a Newton cooling formula. We find that the formation of anticyclones is robust, and that these vortices actively excite density waves, which in turn, transport angular momentum through the disk. Our simulations therefore yield new insights on how the dusty dead zones of protoplanetary disks can transport angular momentum through the disk by purely hydrodynamic processes. Support from NASA’s Origins of Solar Systems program is gratefully acknowledged.

Stewart, Glen R.

2013-10-01

184

Rayleigh-Bénard convection with uniform vertical magnetic field.  

PubMed

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 ?=L(y)/L(x)=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-Ra(c)(Q)}/Ra(c)(Q)](0.91), where Ra(c)(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 r(o)/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. PMID:25314524

Basak, Arnab; Raveendran, Rohit; Kumar, Krishna

2014-09-01

185

Photochemistry and vertical mixing. [in Uranus atmosphere  

NASA Technical Reports Server (NTRS)

Earth-based observations relevant to the question of photochemistry and vertical mixing are discussed. Phytolysis of methane, the only known photochemically active volatile in the Uranian atmosphere, produces heavier hydrocarbons, the most abundant of which are ethane, acetylene, and the polyacetylenes. Unlike Jupiter and Saturn, these hydrocarbon products condense at the low temperatures prevalent in the middle atmosphere. Contrary to the pre-Voyager notion that the atmosphere of Uranus is remarkable clear, it is found that the aerosols are widely and extensively distributed. Despite its photodestruction, methane remains stable in the Uranian atmosphere. The vertical mixing on Uranus is found to be the least efficient of any of the planetary atmospheres.

Atreya, S. K.; Sandel, B. R.; Romani, P. N.

1991-01-01

186

Vertical Component of Satellite Navigation Systems  

NASA Astrophysics Data System (ADS)

The altitude is one of four coordinates of the user's position obtained from Satellite Navigation System (SNS) measurements. The distributions (in per cent) of VDOP coefficient value for different constellations of three SNS - GPS, GLONASS and Galileo - for different masking elevation angles for different user's latitudes are presented in the paper. The results of the measurements of GPS position and vertical accuracy in mode "3D" and position accuracy in mode "2D" for different GPS receivers and different receiver's antenna heights are demonstrated also. Additionally the use of vertical component of SNS in maritime navigation like the determination highly accurate sea-floor depths is presented.

Januszewski, Jacek

2010-01-01

187

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

188

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

189

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

190

Vertical Transmission of Babesia microti, United States  

PubMed Central

Babesiosis is usually acquired from a tick bite or through a blood transfusion. We report a case of babesiosis in an infant for whom vertical transmission was suggested by evidence of Babesia spp. antibodies in the heel-stick blood sample and confirmed by detection of Babesia spp. DNA in placenta tissue. PMID:22840424

Purtill, Kerry; Wong, Susan J.; Munoz, Jose; Teal, Allen; Madison-Antenucci, Susan; Horowitz, Harold W.; Aguero-Rosenfeld, Maria E.; Moore, Julie M.; Abramowsky, Carlos; Wormser, Gary P.

2012-01-01

191

Vertical eddy heat fluxes from model simulations  

NASA Technical Reports Server (NTRS)

Vertical eddy fluxes of heat are calculated from simulations with a variety of climate models, ranging from three-dimensional GCMs to a one-dimensional radiative-convective model. The models' total eddy flux in the lower troposphere is found to agree well with Hantel's analysis from observations, but in the mid and upper troposphere the models' values are systematically 30 percent to 50 percent smaller than Hantel's. The models nevertheless give very good results for the global temperature profile, and the reason for the discrepancy is unclear. The model results show that the manner in which the vertical eddy flux is carried is very sensitive to the parameterization of moist convection. When a moist adiabatic adjustment scheme with a critical value for the relative humidity of 100 percent is used, the vertical transports by large-scale eddies and small-scale convection on a global basis are equal: but when a penetrative convection scheme is used, the large-scale flux on a global basis is only about one-fifth to one-fourth the small-scale flux. Comparison of the model results with observations indicates that the results with the latter scheme are more realistic. However, even in this case, in mid and high latitudes the large and small-scale vertical eddy fluxes of heat are comparable in magnitude above the planetary boundary layer.

Stone, Peter H.; Yao, Mao-Sung

1991-01-01

192

Dynamic alongwind fatigue of slender vertical structures  

Microsoft Academic Search

The wind-excited vibrations of structures induce fluctuating stresses around mean deformation states that lead to fatigue damage accumulation and can determine structural failure without exceeding design wind actions. This paper proposes a mathematical model aimed at deriving a histogram of the stress cycles, the accumulated damage and the fatigue life of slender vertical structures (e.g. towers, chimneys, poles and masts)

Maria Pia Repetto; Giovanni Solari

2001-01-01

193

Dynamic crosswind fatigue of slender vertical structures  

Microsoft Academic Search

Wind-excited vibrations of slender structures can induce fatigue damage and cause structural failure without exceeding ultimate limit state. Unfortunately, the growing importance of this problem is coupled with an evident lack of simple calculation criteria. This paper proposes a mathematical method for evaluating the crosswind fatigue of slender vertical structures, which represents the dual formulation of a parallel method that

Maria Pia Repetto; Giovanni Solari

2002-01-01

194

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

195

Locating vertical well casings with a magnetometer  

SciTech Connect

Prior theoretical results to describe the magnetic field caused by a vertical steel well casing are confirmed by field tests. A proton magnetometer was used to survey a gridded area about a known well casing. The measured magnetic fields are plotted in isometric views to show the steel well casing with and without interfering magnetic fields.

Laine, E.F.; Lytle, R.J.

1982-03-30

196

Food Supply Chains with Vertical Integration  

E-print Network

Food Supply Chains with Vertical Integration SOM 822 Research Paper Diogo Souza-Monteiro Dep. of Resource Economics 05/10/2004 #12;Introduction Food Supply chains are becoming increasingly complex in different tiers of food chains. Barkena and Drabenstott (1995) claim that contracts are quickly taking

Nagurney, Anna

197

Vertical occupational mobility and its measurement  

Microsoft Academic Search

This paper describes a number of alternative approaches to devising a vertical occupational scale and compares the outcomes of different scales on calculations of occupational mobility. The paper describes the conceptual issues relevant to calculating occupational mobility and documents the measurement error embedded in the choice of measure, as applied to different data sets. The ranking schemes used include SOC

Shirley Dex; Joanne Lindley; Kelly Ward

2007-01-01

198

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

199

A Simple Vertical Slab Gel Electrophoresis Apparatus.  

ERIC Educational Resources Information Center

Describes an inexpensive, easily constructed, and safe vertical slab gel kit used routinely for sodium dodecyl sulphate-polyacrylamide gel electrophoresis research and student experiments. Five kits are run from a single transformer. Because toxic solutions are used, students are given plastic gloves and closely supervised during laboratory…

Carter, J. B.; And Others

1983-01-01

200

Surgical correction of primary cutis vertices gyrata.  

PubMed

Primary cutis vertices gyrata is a rare condition of the scalp characterized by the formation of furrows and folds resembling the convolutions of the brain. A review of the English literature did not reveal any surgically treated cases. The authors report three cases treated by simple excision of the deepest furrows with a satisfactory result. PMID:12461454

Al-Malaq, Ali; Hashem, Fuad K; Helmi, Ayman; Al-Qattan, Mohammed M

2002-12-01

201

Viewing Vertical Objects with an Overhead Projector.  

ERIC Educational Resources Information Center

Discusses the use of an overhead projector for the deflection of a vertical image to a screen. Describes three demonstrations: magnetizing of a steel ball bearing and paper clip; convection currents of a hot liquid within a cold liquid; and oscillation of concentrated salt solution into fresh water. (YP)

Wild, R. L.

1988-01-01

202

Vertical axis wind turbine development: Executive summary  

Microsoft Academic Search

Information is presented concerning (1) the numerical solution of the aerodynamics of cross-flow wind turbines; (2) boundary layer considerations for a vertical axis wind turbine (VAWT); (3) VAWT outdoor test model; (4) low solidity blade tests; (5) high solidity blade design; (6) cost analysis of the VAWT test model; (7) structural parametric analysis of VAWT blades; and (8) cost study

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

1979-01-01

203

FUNDAMENTOS TEÓRICOS DE LA INTEGRACIÓN VERTICAL 1  

Microsoft Academic Search

In order to analyze the concept of the vertical integration of companies and the possible effect s on the final prices and the power of market, this article leads from an approach of which it is the company and the relationships that occur internally and externally considering the approach which is different from the neoclassic conventional model. The n, the

José Vicente Cadavid Herrera; John Jairo; García Rendón; Gustavo Adolfo; López Álvarez

204

Vertical File Usage: A Comparative Study.  

ERIC Educational Resources Information Center

Since recorded usage of vertical files in a university library does not always indicate actual needs of patrons, a study was conducted on the use of a collection of 20,000 pamphlets over a three-year period (1972-75). Data were collected from circulation records and from a questionnaire circulated with each pamphlet. Three subject areas had the…

Wells, Dorothy P.

205

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

206

Vertically aligned biaxially textured molybdenum thin films  

SciTech Connect

Vertically aligned, biaxially textured molybdenum nanorods were deposited using dc magnetron sputtering with glancing flux incidence (alpha = 85 degrees 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 degrees 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 [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Riley, Michael [Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lee, Sabrina [US Army Armament Research, Development and Engineering Center, Benet Labs, Watervliet, New York 12189 (United States); Lu, Toh-Ming [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2011-09-15

207

Vertical leaf pressure filter LVAzh 225  

Microsoft Academic Search

A new vertical lead pressure filter LVAzh 225 has been developed with an arrangement for hydraulic coke removal. Industrial trials of the filter, however, showed the service life of the rubber seals of the butterfly valves to be short, so that butterfly valves were replaced by shut-off valves with a pneumatic drive. The prototype of the LVAzh 225 leaf filter

V. I. Fomichev; V. P. Abramov; Y. V. Gutin

1984-01-01

208

Vertical Integration in Building Automation Systems  

Microsoft Academic Search

Building automation systems (BAS) are widely deployed in modern buildings. They are typically engineered adhering to the classical, hierarchical 3-layer model, which has served well in the past but is reaching its limits in complex BAS. The move to more integrated building services also requires tighter integration of the mostly heterogeneous technologies. Vertical integration promises seamless communication from the individual

Stefan Soucek; Dietmar Loy

2007-01-01

209

A vertical MRAM free of write disturbance  

Microsoft Academic Search

Write disturbance in the cross-point addressing scheme employed in most of today's magnetoresistive random access memories (MRAM) designs presents practical limitations in memory element down-size scaling. In this paper, we present a new vertical MRAM design that is free of write disturbance. Its performance is analyzed via micromagnetic modeling. A memory element in this design is of an annular shape

Xiaochun Zhu; Jian-Gang Zhu

2003-01-01

210

Silicon Vertically Integrated Nanowire Field Effect Transistors  

E-print Network

of the threshold voltage is commonly observed due to the presence of surface and interface charge-trapping states. Herein we demonstrate the direct vertical integration of Si nanowire arrays into surrounding gate field challenging issues such as short-channel effects (SCEs), scaling of gate oxide thickness, and increasing power

Yang, Peidong

211

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

212

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

213

Optimal Design of Gear Ratios and Offset for Energy Conservation of an Articulated Manipulator  

Microsoft Academic Search

It is important to minimize the energy dissipated by the reduction gears and motors in a three-jointed vertically articulated manipulator. This paper proposes an optimal design method for simultaneously determining eight design variables, which are three motor masses, three reduction gear ratios, a counterbalancer mass for the third link and an offset between the first and the second links. Using

Teruyuki Izumi; Hai Zhou; Zuowei Li

2009-01-01

214

Growth process conditions of vertically aligned carbon nanotubes using plasma enhanced chemical vapor deposition  

Microsoft Academic Search

The growth of vertically aligned carbon nanotubes using a direct current plasma enhanced chemical vapor deposition system is reported. The growth properties are studied as a function of the Ni catalyst layer thickness, bias voltage, deposition temperature, C2H2:NH3 ratio, and pressure. It was found that the diameter, growth rate, and areal density of the nanotubes are controlled by the initial

M. Chhowalla; K. B. K. Teo; C. Ducati; N. L. Rupesinghe; G. A. J. Amaratunga; A. C. Ferrari; D. Roy; J. Robertson; W. I. Milne

2001-01-01

215

High-definition vertically aligned liquid crystal microdisplays using a circularly polarized light  

NASA Astrophysics Data System (ADS)

A high-definition vertically aligned liquid crystal (LC) microdisplay exhibits a excellent contrast ratio, but its fringing field effect splits the bright state unevenly and leads to a very slow response time. By utilizing a circularly polarized light instead of conventional linearly polarized light, we have overcome the long-standing problems of poor sharpness, low brightness, and slow response time. Confirming computer simulations agree with the experimental results well. This approach can be applied to both reflective and transmissive LC microdisplays.

Fan-Chiang, Kuan-Hsu; Chen, Shu-Hsia; Wu, Shin-Tson

2005-07-01

216

Transient natural convection along vertical cylinder with Heat and Mass transfer  

NASA Astrophysics Data System (ADS)

A numerical solution for the transient natural convection flow over a vertical cylinder under the combined buoyancy effect of heat and mass transfer is presented. The velocity, temperature and concentration profiles, local and average skin-friction, Nusselt number and Sherwood number are shown graphically. It is observed that time taken to reach steady state increases with Schmidt number and decreases as combined buoyancy ratio parameter N increases. Stability and convergence of the finite difference scheme are established.

Ganesan, P.; Rani, H. P.

217

Observations of layers in ozone vertical profiles from SAGE II (v 6.0) measurements  

Microsoft Academic Search

Layered structures in the vertical profiles of ozone mixing ratio as retrieved by the Stratospheric Aerosol and Gas Experiment (SAGE II) version 6.0 have been studied in the altitude range 10-28 km in the middle and high latitudes (30-75 N and S). 12 years of data (1985-1990, 1994-1999) have been used to build a climatology of layers with thickness of

J. Kar; C. R. Trepte; L. W. Thomason; J. M. Zawodny

2002-01-01

218

Observations of layers in ozone vertical profiles from SAGE II (v 6.0) measurements  

Microsoft Academic Search

Layered structures in the vertical profiles of ozone mixing ratio as retrieved by the Stratospheric Aerosol and Gas Experiment (SAGE II) version 6.0 have been studied in the altitude range 10–28 km in the middle and high latitudes (30–75 N and S). 12 years of data (1985–1990, 1994–1999) have been used to build a climatology of layers with thickness of

J. Kar; C. R. Trepte; L. W. Thomason; J. M. Zawodny

2002-01-01

219

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

220

A numerical study based on a weakly compressible formulation for thermosolutal convection in vertical cavities  

NASA Astrophysics Data System (ADS)

Laminar thermosolutal convection in cavities with uniform, constant temperature and mass fraction profiles at the vertical side is studied numerically. The study is conducted in the case where an inert carrier gas (species “1”) present in the cavity is not soluble in species “2”, and do not diffuse into the walls. A mass flux of species “2” into the cavity occurs at the hot vertical wall and a mass flux out of the cavity occurs at the opposite cold wall. The weakly compressible model proposed in this work was used to investigate the flow fields, and heat and mass transfer in cavities filled with binary mixtures of ideal gases. The dimensionless form of the seven governing equations for constant thermophysical properties, except density, show that the problem formulation involves ten dimensionless parameters. The results were validated against numerical results published in the literature for purely thermal convection, and thermodynamic predictions for transient thermosolutal flows. A parametric study has been performed to investigate the effects of the initial conditions, molecular weight ratio, Lewis number, and aspect ratio of the cavity for aiding or opposing buoyancy forces. For the range of parameters considered, the results show that variations in the density field have larger effects on mass transfer than on heat transfer. For opposing buoyancy forces, the numerical simulations predict complex flow structures and possible chaotic behavior for rectangular vertical cavities according to the value of the molecular weight ratio.

Sun, Hua; Lauriat, Guy

2010-05-01

221

Conjugate Effects on Steady Laminar Natural Convection Heat Transfer in Vertical Eccentric Annuli  

NASA Astrophysics Data System (ADS)

Combined conduction-free convection heat transfer in vertical eccentric annuli is numerically investigated using finite-difference technique. Numerical results are presented for a fluid of Prandtl number 0.7 in an annulus of radius ratio 0.5 and dimensionless eccentricity 0.5. The conjugation effect on the induced flow rate and the total heat absorbed in the annulus is presented for the case of one wall being isothermally heated while the other wall is kept at inlet fluid temperature. The conjugate effects are controlled by solid-fluid conductivity ratio, cylinder walls thickness and dimensionless channel height (i.e. Grashof number). Solid-fluid conductivity ratio is varied over a range that covers practical cases with commonly encountered inner and outer walls thickness. Values of conductivity ratio over which conjugate effect can be neglected have been obtained.

El-Shaarawi, Maged A. I.; Mokheimer, Esmail M. A.; Jamal, Ahmad

2005-12-01

222

Tropopause Height's influences on vertical ozone structure in Ankara, Turkey  

NASA Astrophysics Data System (ADS)

The changes in ozone and the temperature profiles in mid-latitudes of lower stratosphere are consistent with the assumption of a change in vertical transport. The variability of total ozone in these latitudes may be related to the tropopause heights. Stratospheric ozone observations based on balloon-borne ozonesonde from Ankara (40^oN;33^oE) by Turkish State Meteorological Service (TSMS) began in January 1994. The measurement program is currently continuing at taken State Meteorological Station. The ECC ozonesonde has been used by chemical means as the instrument ascents through the atmosphere by balloon. In this study, we attempt to present the results of analyses of tropopause heights and their influences on total ozone variability in Ankara. Due to the strong dynamical processes, and associated atmospheric transport, which are the main reasons of the variability in the vertical ozone profiles in mid-latitudes, the tropopause heights and temperature and ozone mixing ratio profiles in Ankara were examined. It is founded that the average value of total column ozone amount by ozonesounding is 320 DU with a standard deviation ± 43 in the period of 1994-2001 in Ankara. The monthly average total column ozone varied in between 250 to 419 DU. In this study, we have considered a classification of the observed data according to the low and high tropopause heights corresponding to ozone mixing ratio profiles for the winter (DJF) and the summer (JJA). For this purpose we assumed a range in between 8.5-10.0 km heights for low tropopause; 10.0 km and higher for high tropopause respectively. About 151 soundings from January 1994 to December 2001 are used in this analysis. Of all 151 sounding used, 47 fall in winter period and 29 in summer period. Furthermore 43 from total sounding correspond to the lower tropopause height and 108 to the higher class. Furthermore, the average ozone mixing ratio profiles for the low and high tropopause groups are obtained. The correlation between total column ozone and tropopause heights has important implications for the interpretation of long-term trends in total ozone. For this purpose, we examined the relationships between total ozone and tropopause height.

Demirhan, D.; Kahya, C.; Topcu, S.; Incecik, S.

2003-04-01

223

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

224

Inbreeding and parasite sex ratios.  

PubMed Central

The breeding system of parasitic protozoa affects the evolution of drug resistance and virulence, and is relevant to disease diagnosis and the development of chemo- and immunotherapy. A major group of protozoan parasites, the phylum Apicomplexa, that includes the aetiological agents of malaria, toxoplasmosis and coccidiosis, all have dimorphic sexual stages. The sex ratio (proportion of males produced by parasites) is predicted to depend upon the inbreeding rate, and it has been suggested that sex-ratio data offer a relatively cheap and easy method for indirectly estimating inbreeding rates. Here, we exploit a new theoretical machinery to show that there are generally valid relationships between f, Wright's coefficient of inbreeding, and sex ratio, z(*), the generality being with respect to population structure. To focus the discussion, we concentrate on malaria and show that the previously derived result, f = 1 - 2z(*), does not depend on the artificial assumptions about population structure that were previously made. Not only does this justify the use of sex ratio as an indirect measure of f, but also we argue that it may actually be preferable to measure f by measuring sex ratios, rather than by measuring departures from Hardy-Weinberg genotypic proportions both in malaria and parasites more generally. PMID:11934369

Nee, Sean; West, Stuart A; Read, Andrew F

2002-01-01

225

Effect of gravity on vertical eye position.  

PubMed

There is growing evidence that gravity markedly influences vertical eye position and movements. A new model for the organization of brainstem upgaze pathways is presented in this review. The crossing ventral tegmental tract (CVTT) could be the efferent tract of an "antigravitational" pathway terminating at the elevator muscle motoneurons in the third nerve nuclei and comprising, upstream, the superior vestibular nucleus and y-group, the flocculus, and the otoliths. This pathway functions in parallel to the medial longitudinal fasciculus pathways, which control vertical eye movements made to compensate for all vertical head movements and may also comprise the "gravitational" vestibular pathways, involved in the central reflection of the gravity effect. The CVTT could provide the upgaze system with the supplement of tonic activity required to counteract the gravity effect expressed in the gravitational pathway, being permanently modulated according to the static positions of the head (i.e., the instantaneous gravity vector) between a maximal activity in the upright position and a minimal activity in horizontal positions. Different types of arguments support this new model. The permanent influence of gravity on vertical eye position is strongly suggested by the vertical slow phases and nystagmus observed after rapid changes in hypo- or hypergravity. The chin-beating nystagmus, existing in normal subjects with their head in the upside-down position, suggests that gravity is not compensated for in the downgaze system. Upbeat nystagmus due to brainstem lesions, most likely affecting the CVTT circuitry, is improved when the head is in the horizontal position, suggesting that this circuitry is involved in the counteraction of gravity between the upright and horizontal positions of the head. In downbeat nystagmus due to floccular damage, in which a permanent hyperexcitation of the CVTT could exist, a marked influence of static positions of the head is also observed. Finally, the strongest argument supporting a marked role of gravity in vertical eye position is that the eye movement alterations observed in the main, typical physiological and pathological conditions are precisely those that would be expected from a direct effect of gravity on the eyeballs, with, moreover, no single alternative interpretation existing so far that could account for all these different types of findings. PMID:19645894

Pierrot-Deseilligny, C

2009-05-01

226

Habitat Demonstration Unit (HDU) Vertical Cylinder Habitat  

NASA Technical Reports Server (NTRS)

NASA's Constellation Architecture Team defined an outpost scenario optimized for intensive mobility that uses small, highly mobile pressurized rovers supported by portable habitat modules that can be carried between locations of interest on the lunar surface. A compact vertical cylinder characterizes the habitat concept, where the large diameter maximizes usable flat floor area optimized for a gravity environment and allows for efficient internal layout. The module was sized to fit into payload fairings for the Constellation Ares V launch vehicle, and optimized for surface transport carried by the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) mobility system. Launch and other loads are carried through the barrel to a top and bottom truss that interfaces with a structural support unit (SSU). The SSU contains self-leveling feet and docking interfaces for Tri-ATHLETE grasping and heavy lift. A pressurized module needed to be created that was appropriate for the lunar environment, could be easily relocated to new locations, and could be docked together in multiples for expanding pressurized volume in a lunar outpost. It was determined that horizontally oriented pressure vessels did not optimize floor area, which takes advantage of the gravity vector for full use. Hybrid hard-inflatable habitats added an unproven degree of complexity that may eventually be worked out. Other versions of vertically oriented pressure vessels were either too big, bulky, or did not optimize floor area. The purpose of the HDU vertical habitat module is to provide pressurized units that can be docked together in a modular way for lunar outpost pressurized volume expansion, and allow for other vehicles, rovers, and modules to be attached to the outpost to allow for IVA (intra-vehicular activity) transfer between them. The module is a vertically oriented cylinder with a large radius to allow for maximal floor area and use of volume. The modular, 5- m-diameter HDU vertical habitat module consists of a 2-m-high barrel with 0.6-mhigh end domes forming the 56-cubicmeter pressure vessel, and a 19-squaremeter floor area. The module has up to four docking ports located orthogonally from each other around the perimeter, and up to one docking port each on the top or bottom end domes. In addition, the module has mounting trusses top and bottom for equipment, and to allow docking with the ATHLETE mobility system. Novel or unique features of the HDU vertical habitat module include the nodelike function with multiple pressure hatches for docking with other versions of itself and other modules and vehicles; the capacity to be carried by an ATHLETE mobility system; and the ability to attach inflatable 'attic' domes to the top for additional pressurized volume.

Howe, Alan; Kennedy, Kriss J.; Gill, Tracy R.; Tri, Terry O.; Toups, Larry; Howard, Robert I.; Spexarth, Gary R.; Cavanaugh, Stephen; Langford, William M.; Dorsey, John T.

2014-01-01

227

H/V Ratio Characteristics for 3-Component Seismic Sensors  

NASA Astrophysics Data System (ADS)

Information about the stability of the ground on which a structure will be built is crucial for various geotechnical and safety purposes. With the goal of being able to monitor for changes in stability, we have explored a method to study the distribution of seismic energy in a half-space model as well as to obtain information about the way in which this energy distribution depends on physical properties of the ground. The procedure and results of this study are purely theoretical and they are developed from a more detail study of the expressions for the characteristics of a single geophone specified by Dankbar [1]. It is worth highlighting that these equations exclude the contribution of surface waves and that they work under the assumption that we are only interested in the effects of body waves. In order to understand the distribution of seismic energy detected by a single 3-component sensor, we looked at the energy stored individually in P-waves and S-waves on both the vertical and horizontal geophone components for a white source. Through our analysis, we showed that any changes in the shear modulus of the ground (and thus shear wave velocity) are propositional to changes in the distribution of energies between the vertical and horizontal components recorded by a 3-component seismic sensor (geophone). This observation provides us with a unique opportunity to use the H/V ratio (the ratio of the signal amplitude on the horizontal component(s) to that on the vertical component, also known as the 'transfer function', usually expressed as a function of frequency) to monitor for variations in the shear modulus of the ground. We show, through time-series analysis of numerous hours (60 GB of data per sensor) of 3-component seismic data, that it may be possible to use the long-term average of the H/V ratio to obtain a stable estimate of the ratio itself. A deviation from this estimate over a long period of time would then indicate that the average shear-wave velocity, and thus the shear modulus and indeed the stability of the ground, might have changed. References [1] Daankbar J.W.M., Separation of P- and S-Waves, Geophysical Prospecting 33, pp. 970-986, 1985. [2] Kaehler S. and Meissner R., Radiation and Receiver Pattern of Shear and Compressional Waves as a Function of Poisson's Ratio, Geophysical Prospecting 31, pp. 421-435, 1983.

Villero, D. A.; Porter, J.; Milkereit, B.

2013-12-01

228

Quadrature surface coils for in vivo imaging in 900-MHz vertical bore spectrometer B. L. Beck1,2  

E-print Network

Na. The 900-MHz, 105-mm ultra-widebore vertical magnet developed by the NHMFL and commissioned loop contained 3 distributed capacitors and shared a common leg with a dedicated capacitor to adjust ratio and is the pulse duration of transmission. Images were acquired on the 21.1-T ultra

McQuade, D. Tyler

229

The conjugate conduction–natural convection heat transfer along a thin vertical plate with non-uniform internal heat generation  

Microsoft Academic Search

The steady state heat transfer characteristics of a thin vertical strip with internal heat generation is studied in this work. The nondimensional temperature distribution in the strip is obtained as a function of the following parameters: (a) the intensity and distribution of the internal heat sources, (b) the aspect ratio of the strip, (c) the longitudinal heat conductance of the

F Méndez; C Treviño

2000-01-01

230

A boundary layer analysis for entrance region heat transfer in vertical microchannels within the slip flow regime  

Microsoft Academic Search

A boundary layer integral analysis has been executed to investigate the heat transfer characteristics of natural convection gas flows in symmetrically heated vertical microchannels, under the conditions of large channel aspect ratios, in the slip flow regime. It has been revealed that for low values of Rayleigh number, the entrance region length is only a small fraction of the total

Suman Chakraborty; S. K. Som; Rahul

2008-01-01

231

Discovering Phi: The Golden Ratio  

NSDL National Science Digital Library

Students discover the mathematical constant phi, the golden ratio, through hands-on activities. They measure dimensions of "natural objects"—a star, a nautilus shell and human hand bones—and calculate ratios of the measured values, which are close to phi. Then students learn a basic definition of a mathematical sequence, specifically the Fibonacci sequence. By taking ratios of successive terms of the sequence, they find numbers close to phi. They solve a squares puzzle that creates an approximate Fibonacci spiral. Finally, the instructor demonstrates the rule of the Fibonacci sequence via a LEGO® MINDSTORMS® NXT robot equipped with a pen. The robot (already created as part of the companion activity, The Fibonacci Sequence & Robots) draws a Fibonacci spiral that is similar to the nautilus shape.

AMPS GK-12 Program,

232

Measurement of tau branching ratios  

Microsoft Academic Search

We have measured the branching ratios for several tau decay modes. We use e+e--->tau+tau- 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 tau decay are measured to be B1=(84.7+\\/-1.0)%

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

1987-01-01

233

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.

234

Ultimately short ballistic vertical graphene Josephson junctions  

PubMed Central

Much efforts have been made for the realization of hybrid Josephson junctions incorporating various materials for the fundamental studies of exotic physical phenomena as well as the applications to superconducting quantum devices. Nonetheless, the efforts have been hindered by the diffusive nature of the conducting channels and interfaces. To overcome the obstacles, we vertically sandwiched a cleaved graphene monoatomic layer as the normal-conducting spacer between superconducting electrodes. The atomically thin single-crystalline graphene layer serves as an ultimately short conducting channel, with highly transparent interfaces with superconductors. In particular, we show the strong Josephson coupling reaching the theoretical limit, the convex-shaped temperature dependence of the Josephson critical current and the exceptionally skewed phase dependence of the Josephson current; all demonstrate the bona fide short and ballistic Josephson nature. This vertical stacking scheme for extremely thin transparent spacers would open a new pathway for exploring the exotic coherence phenomena occurring on an atomic scale. PMID:25635386

Lee, Gil-Ho; Kim, Sol; Jhi, Seung-Hoon; Lee, Hu-Jong

2015-01-01

235

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

236

Coupled Resonator Vertical Cavity Laser Diode  

SciTech Connect

We report the operation of an electrically injected monolithic coupled resonator vertical cavity laser which consists of an active cavity containing In{sub x}Ga{sub 1{minus}x}As quantum wells optically coupled to a passive GaAs cavity. This device demonstrates novel modulation characteristics arising from dynamic changes in the coupling between the active and passive cavities. A composite mode theory is used to model the output modulation of the coupled resonator vertical cavity laser. It is shown that the laser intensity can be modulated by either forward or reverse biasing the passive cavity. Under forward biasing, the modulation is due to carrier induced changes in the refractive index, while for reverse bias operation the modulation is caused by field dependent cavity enhanced absorption.

CHOQUETTE, KENT D.; CHOW, WENG W.; FISCHER, ARTHUR J.; GEIB, KENT M.; HOU, HONG Q.

1999-09-16

237

Present day vertical deformation in New Zealand  

NASA Astrophysics Data System (ADS)

New Zealand is tectonically very active. It lies along the oblique convergent plate boundary between the Pacific and Australian plate. In the North Island active tectonics is dominated by westward subduction of the Pacific Plate beneath the eastern North Island at the Hikurangi Trench, strike-slip faulting in the upper plate, and back-arc rifting in the central North Island. A series of very large strike-slip faults run through the South Island (Marlborough Fault System and the Alpine Fault) connecting with the Puysegur subduction zone in the south. The present day uplift rates are evaluated by analyzing data from continuous GPS stations in New Zealand. The up to 20 years of continuous GPS gives us a snapshot into the deformation rate. The average velocity is corrected for significant coseismic offsets, but the data can also be influenced by postseismic deformation, slow slip events along the Hikurangi subduction zone, volcanic deformation, as well as none tectonic local affects such as water extraction. We evaluate the interseismic vertical rate. We exclude data significantly affected by postseismic deformation from recent earthquakes and provide vertical rates both with and without correcting for slow slip events. Outside the Taupo rift zone the vertical rates are range from -6 to +6 mm/yr with uplift observed across the Alpine fault, few mm/yr uplift around the Raukumara Peninsula, northeast North Island, and subsidence along the southeast North Island, reflecting variation in plate locking. We compare the present day vertical deformation to the long-term motion along the coast determined primarily from 125,000 years old marine geological markers. The largest proportion of the New Zealand coastline (45%) is undergoing long-term tectonic uplift. Small stretches of the coastline (15%) are undergoing long-term subsidence. Areas farthest from the plate boundary (northern North Island and southeastern South Island) are assessed to be tectonically stable, in agreement with the continuous GPS data.

Hreinsdóttir, Sigrún; Wallace, Laura; Litchfield, Nicola; D'Anastasio, Elisabetta; Denys, Paul; Pearson, Christopher

2014-05-01

238

Electrically floating, near vertical incidence, skywave antenna  

SciTech Connect

An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

2014-07-08

239

Spirit 360-Degree View, Sol 388 (vertical)  

NASA Technical Reports Server (NTRS)

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 388th martian day, or sol (Feb. 4, 2005). Spirit had driven about 13 meters (43 feet) uphill toward 'Cumberland Ridge' on this sol. This location is catalogued as Spirit's Site 102, Position 513. The view is presented in a vertical projection with geometric and brightness seam correction.

2005-01-01

240

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

241

Method to Compute the Vertical Deflection Components  

Microsoft Academic Search

\\u000a To make a more exact mathematical model of the global atmosphere circulation and to improve the weather forecast one needs\\u000a to take into account the Vertical Deflection Components (VDCs). The required accuracy for these tasks is 1–2?? now and 0.4–1.0?? in future. The VDCs were calculated by integration of the free air gravity anomalies (taken from the Internet site of

E. A. Boyarsky; L. V. Afanasieva; V. N. Koneshov

242

Record Drive Day, Opportunity Sol 383 (vertical)  

NASA Technical Reports Server (NTRS)

NASA's Mars Exploration Rover Opportunity set a one-day distance record for martian driving on the rover's 383rd martian day, or sol, which began on Feb. 19, 2005. Opportunity rolled 177.5 meters (582 feet) across the plain of Meridiani on that sol. It used its navigation camera after the drive to take the images that are combined into this mosaic view. The view is presented here in a vertical projection with geometric seam correction.

2005-01-01

243

Vertical leaf pressure filter LVAzh 225  

SciTech Connect

A new vertical lead pressure filter LVAzh 225 has been developed with an arrangement for hydraulic coke removal. Industrial trials of the filter, however, showed the service life of the rubber seals of the butterfly valves to be short, so that butterfly valves were replaced by shut-off valves with a pneumatic drive. The prototype of the LVAzh 225 leaf filter has been recommended for series production.

Fomichev, V.I.; Abramov, V.P.; Gutin, Y.V.

1984-01-01

244

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

245

The vertical distribution of tropospheric ammonia  

NASA Technical Reports Server (NTRS)

A one-dimensional tropospheric photochemical model is used to simulate measured profiles of NH3 obtained with the Infrared Heterodyne Radiometer. The relative roles of homogeneous loss, heterogeneous loss, and vertical eddy transport are discussed in terms of selecting parameters which best fit the measurements. The best fit was obtained for a vertical eddy diffusion coefficient of 200,000/sq cm per sec or greater (corresponding to a characteristic vertical transport time in excess of about 35 days), and a characteristic heterogeneous loss time in excess of 10 days. The characteristic homogeneous chemical loss time was found to be about 40 days at the surface and decreased to about 180 days at 10 km, and not very sensitive to model chemical perturbations. Increased ground-level concentrations of NH3 to about 10 ppb, compared to background surface concentrations of about 1 ppb, were measured several weeks after application of ammonium nitrate fertilizer. This suggests that the volatilization of ammonium nitrate fertilizer is rapid, and an important source of NH3. Because of the characteristic times for the loss mechanisms, synoptic time-scale phenomena may play an important role in determining the tropospheric distribution of NH3 concentrations.

Levine, J. S.; Hoell, J. M.; Augustsson, T. R.

1980-01-01

246

A Ratio Explanation for Evolution.  

ERIC Educational Resources Information Center

Describes hands-on physical anthropology activities for teaching students about evolution. Using evidence found in hominid skulls, students conduct investigations that involve calculating ratios. Eight full-page photographs of skulls from the program Stones and Bones are included. (PR)

Riss, Pam Helfers

1993-01-01

247

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

248

Envera Variable Compression Ratio Engine  

Microsoft Academic Search

Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy

Charles Mendler

2011-01-01

249

Random Cross Ratios Kalle strm  

E-print Network

systems. A short background into invariant based recognition is given. The use of the result ratio, e.g. in autonomous vehicle navigation, object recognition and reconstruction from images. 1 have become increasingly popular in Computer Vision, e.g. in reconstruction and recognition algorithms

Lunds Universitet

250

Optimal gear ratios of drives  

Microsoft Academic Search

One of the most complex problems in the design of practically any mechanism or machine is to select the gear ratio of an electric drive, on the basis of scientific, engineering, and economic principles. There is an extensive literature on this subject, dating mainly to the period from the 1940s to the 1960s. In current economic conditions, however, this problem

B. N. Polyakov

2007-01-01

251

ostglacial rebound from VLBI Geodesy: On Establishing Vertical Reference  

NASA Technical Reports Server (NTRS)

I propose that a useful reference frame for vertical motions is that found by minimizing differences between vertical motions observed with VLBI [Ma and Ryan, 1995] and predictions from postglacial rebound predictions [Peltier, 1995].

Argus, Donald .

1996-01-01

252

A Vertical Grid Module for Baroclinic Models of the Atmosphere  

SciTech Connect

The vertical grid of an atmospheric model assigns dynamic and thermo- dynamic variables to grid locations. The vertical coordinate is typically not height but one of a class of meteorological variables that vary with atmo- spheric conditions. The grid system is chosen to further numerical approx- imations of the boundary conditions so that the system is terrain following at the surface. Lagrangian vertical coordinates are useful in reducing the numerical errors from advection processes. That the choices will effect the numercial properties and accuracy is explored in this report. A MATLAB class for Lorentz vertical grids is described and applied to the vertical struc- ture equation and baroclinic atmospheric circulation. A generalized meteo- rolgoical coordinate system is developed which can support ?, isentropic ? vertical coordinate, or Lagrangian vertical coordinates. The vertical atmo- spheric column is a MATLAB class that includes the kinematic and ther- modynamic variables along with methods for computing geopoentials and terms relevant to a 3D baroclinc atmospheric model.

Drake, John B [ORNL

2008-04-01

253

Functionality Tuning in Vertically Aligned Nanocomposite Thin Films  

E-print Network

Vertically aligned nanocomposite (VAN) oxide thin films are unique nanostructures with two-phase self-assembled, heteroepitaxially grown on single-crystal substrates. Both phases tend to grow vertically and simultaneously on a given substrate...

Chen, Aiping

2013-04-04

254

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 Joint, Vertical Cross Bracing End Detail - Ceylon Covered Bridge, Limberlost Park, spanning Wabash River at County Road 900 South, Geneva, Adams County, IN

255

Assessing and Predicting Vertical Intent for Web Queries  

E-print Network

usefulness of a vertical, especially as the vertical items are hidden), this assumption eases the assessment, blog, answer, shopping, discussion, scholar, wiki) and contains 320 web topics. Assessors were

Jose, Joemon M.

256

Vertical variations in wood CO2 efflux for live emergent trees in a Bornean tropical rainforest.  

PubMed

Difficult access to 40-m-tall emergent trees in tropical rainforests has resulted in a lack of data related to vertical variations in wood CO2 efflux, even though significant variations in wood CO2 efflux are an important source of errors when estimating whole-tree total wood CO2 efflux. This study aimed to clarify vertical variations in wood CO2 efflux for emergent trees and to document the impact of the variations on the whole-tree estimates of stem and branch CO2 efflux. First, we measured wood CO2 efflux and factors related to tree morphology and environment for seven live emergent trees of two dipterocarp species at four to seven heights of up to ? 40 m for each tree using ladders and a crane. No systematic tendencies in vertical variations were observed for all the trees. Wood CO2 efflux was not affected by stem and air temperature, stem diameter, stem height or stem growth. The ratios of wood CO2 efflux at the treetop to that at breast height were larger in emergent trees with relatively smaller diameters at breast height. Second, we compared whole-tree stem CO2 efflux estimates using vertical measurements with those based on solely breast height measurements. We found similar whole-tree stem CO2 efflux estimates regardless of the patterns of vertical variations in CO2 efflux because the surface area in the canopy, where wood CO2 efflux often differed from that at breast height, was very small compared with that at low stem heights, resulting in little effect of the vertical variations on the estimate. Additionally, whole-tree branch CO2 efflux estimates using measured wood CO2 efflux in the canopy were considerably different from those measured using only breast height measurements. Uncertainties in wood CO2 efflux in the canopy did not cause any bias in stem CO2 efflux scaling, but affected branch CO2 efflux. PMID:24876294

Katayama, Ayumi; Kume, Tomonori; Komatsu, Hikaru; Ohashi, Mizue; Matsumoto, Kazuho; Ichihashi, Ryuji; Kumagai, Tomo'omi; Otsuki, Kyoichi

2014-05-01

257

Kinematics of Vertical Saccades during the Yaw Vestibulo-ocular Reflex in Humans  

PubMed Central

Purpose Listing’s law (LL) constrains the rotational axes of saccades and pursuit eye movements to Listing’s plane (LP). In the velocity domain, LL is ordinarily equivalent to a tilt in the ocular velocity axis equal to half the change in eye position, giving a tilt angle ratio (TAR) of 0.5. This study was undertaken to investigate vertical saccade behavior after the yaw vestibulo-ocular reflex (VOR) had driven eye torsion out of LP, an initial condition causing the position and velocity domain formulations of LL to differ. Methods Binocular eye and head motions were recorded with magnetic search coils in eight humans. With the head immobile, LP was determined for each eye, and mean TAR was 0.50 ± 0.07 (mean ± SD) for horizontal and 0.45 ± 0.11 for vertical saccades. The VOR was evoked by transient, whole-body yaw at 2800 deg/s2 peak acceleration, capable of evoking large, uninterrupted VOR slow phases. Before rotation, subjects viewed a target at eye level, 20° up, or 20° down. In two thirds of the trials, the target moved upward or downward at systematically varying times, triggering a vertical saccade during the horizontal VOR slow phase. Results Because the head rotation axis was generally misaligned with LP, the eye averaged 3.6° out of LP at vertical saccade onset. During the saccade, eye position continued to depart LP by an average 0.8°. The horizontal TAR at saccade onset was 0.29 ± 0.07. At peak saccade velocity 35 ± 3 ms later, the vertical TAR was 0.45 ± 0.07, statistically similar to that of head fixed saccades. Saccades did not return to LP. Conclusions Although they did not observe the position domain formulation of LL, vertical saccades, during the VOR, observed the half-angle velocity domain formulation of LL. PMID:16043853

Crane, Benjamin T.; Tian, Junru; Demer, Joseph L.

2007-01-01

258

Waterflood Profiles and Oil Recovery with Vertical and Horizontal Wells  

Microsoft Academic Search

Experimental and numerical study is conducted to investigate the performance of a horizontal well during waterflooding of a sandstone outcrop. Three different well configurations, viz., vertical injection-vertical production (VI-VP), vertical injection-top horizontal production (VI-HPT), and vertical injection-bottom horizontal production (VI-HPB) are considered. The commercial simulator, ECLIPSE, is used for the numerical study, and history matching technique has been used to

N. Hadia; L. Chaudhari; S. K. Mitra; M. Vinjamur; R. Singh

2008-01-01

259

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

260

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...

261

Reflex vertical gaze and the medial longitudinal fasciculus  

Microsoft Academic Search

Extraocular movements were investigated in a patient with bilateral vascular lesions of the medial longitudinal fasciculus. The patient showed voluntary and reflex horizontal gaze consistent with his lesion, but had absent reflex vertical gaze. Voluntary vertical gaze was present. Necropsy was performed, and the findings suggest that the medial longitudinal fasciculi in the pons conveys impulses for reflex vertical gaze,

L. R. Jenkyn; G. Margolis; A. G. Reeves

1978-01-01

262

A Micromirror With Large Static Rotation and Vertical Actuation  

Microsoft Academic Search

A micromirror with large rotation angle and vertical displacement is proposed and developed. The proposed micromirror is actuated by newly developed prestress comb drive actuators, which exhibit no pull-in, no hysteresis, and large vertical displacement range characteristics. The micromirror was fabricated using commercially available PolyMUMPs. Experimental results indicated that the maximum rotation angle and vertical displacement of the device are

Jin-Chern Chiou; Chin-Fu Kou; Yung-Jiun Lin

2007-01-01

263

Adaptation of vertical eye alignment in relation to head tilt  

Microsoft Academic Search

Binocular visual feedback is used to continually calibrate binocular eye alignment so that the retinal images of the two eyes remain in correspondence. Past experiments have shown that vertical eye alignment (measured as vertical phoria) can be altered by training to disparities that vary as a function of orbital eye position. The present experiments demonstrate that vertical eye alignment can

James S. Maxwell; Clifton M. Schor

1996-01-01

264

33 CFR 118.85 - Lights on vertical lift bridges.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Lights on vertical lift bridges. 118.85 Section...LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every...

2014-07-01

265

ARM Energy Balance Bowen Ratio (EBBR) station: surf. heat flux and related data, 30-min  

SciTech Connect

The Energy Balance Bowen Ratio (EBBR) system produces 30-min 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. 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, David

1993-07-04

266

ARM Energy Balance Bowen Ratio (EBBR) station: surf. heat flux and related data, 30-min  

DOE Data Explorer

The Energy Balance Bowen Ratio (EBBR) system produces 30-min 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. 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, David

267

Blowing Ratio Effects on Film Cooling Effectiveness  

E-print Network

coolant tends to attach closer to the blade surface compared to the light density ratio coolant at the same blowing ratio. 10 Sinha et al. [18] studied similarly on various density ratio coolants under different blowing ratio. For a constant density ratio...

Liu, Kuo-Chun

2010-01-14

268

Optomechanical Raman-Ratio Thermometry  

E-print Network

The temperature dependence of the asymmetry between Stokes and anti-Stokes Raman scattering can be exploited for self-calibrating, optically-based thermometry. In the context of cavity optomechanics, we observe the cavity-enhanced scattering of light interacting with the standing-wave drumhead modes of a silicon nitride membrane mechanical resonator. The ratio of the amplitude of Stokes to anti-Stokes scattered light is used to measure temperatures of optically-cooled mechanical modes down to the level of a few vibrational quanta. We demonstrate that the Raman-ratio technique is able to measure the physical temperature of our device over a range extending from cryogenic temperatures to within an order of magnitude of room temperature.

T. P. Purdy; P. -L. Yu; N. S. Kampel; R. W. Peterson; K. Cicak; R. W. Simmonds; C. A. Regal

2014-06-27

269

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

270

Models of Ratio Schedule Performance  

PubMed Central

Predictions of P. R. Killeen's (1994) mathematical principles of reinforcement were tested for responding on ratio reinforcement schedules. The type of response key, the number of sessions per condition, and first vs. second half of a session had negligible effects on responding. Longer reinforcer durations and larger grain types engeridered more responding, affecting primarily the parameter a (specific activation). Key pecking was faster than treadle pressing, affecting primarily the parameter ? (response time). Longer intertrial intervals led to higher overall response rates and shorter postreinforcement pauses and higher running rates, and ruled out some competing explanations. The treadle data required a distinction between the energetic requirements and rate-limiting properties of extended responses. The theory was extended to predict pause durations and run rates on ratio schedules. PMID:9206029

Bizo, Lewis A.; Killeen, Peter R.

2008-01-01

271

The subjective visual vertical and the perceptual upright.  

PubMed

The direction of 'up' has traditionally been measured by setting a line (luminous if necessary) to the apparent vertical, a direction known as the 'subjective visual vertical' (SVV); however for optimum performance in visual skills including reading and facial recognition, an object must to be seen the 'right way up'--a separate direction which we have called the 'perceptual upright' (PU). In order to measure the PU, we exploited the fact that some symbols rely upon their orientation for recognition. Observers indicated whether the symbol 'horizontal P' presented in various orientations was identified as either the letter 'p' or the letter 'd'. The average of the transitions between 'p-to-d' and 'd-to-p' interpretations was taken as the PU. We have labelled this new experimental technique the Oriented CHAracter Recognition Test (OCHART). The SVV was measured by estimating whether a line was rotated clockwise or counter-clockwise relative to gravity. We measured the PU and SVV while manipulating the orientation of the visual background in different observer postures: upright, right side down and (for the PU) supine. When the body, gravity and the visual background were aligned, the SVV and the PU were similar, but as the background orientation and observer posture orientations diverged, the two measures varied markedly. The SVV was closely aligned with the direction of gravity whereas the PU was closely aligned with the body axis. Both probes showed influences of all three cues (body orientation, vision and gravity) and these influences could be predicted from a weighted vectorial sum of the directions indicated by these cues. For the SVV, the ratio was 0.2:0.1:1.0 for the body, visual and gravity cues, respectively. For the PU, the ratio was 2.6:1.2:1.0. In the case of the PU, these same weighting values were also predicted by a measure of the reliability of each cue; however, reliability did not predict the weightings for the SVV. This is the first time that maximum likelihood estimation has been demonstrated in combining information between different reference frames. The OCHART technique provides a new, simple and readily applicable method for investigating the PU which complements the SVV. Our findings suggest that OCHART is particularly suitable for investigating the functioning of visual and non-visual systems and their contributions to the perceived upright of novel environments such as high- and low-g environments, and in patient and ageing populations, as well as for normal observers. PMID:16550392

Dyde, Richard T; Jenkin, Michael R; Harris, Laurence R

2006-09-01

272

Geometry of operator cross ratio  

NASA Astrophysics Data System (ADS)

The operator cross ratio, which is meaningful, in particular, for the infinite-dimensional Sato Grassmannian is defined and investigated. Its homological interpretation is presented. A matrix and operator analogue of the Schwartzian differential operator is introduced and its relation to linear Hamiltonian systems and Riccati's equation is established. The aim of these constructions is application to the KP-hierarchy (the Kadomtsev-Petviashvili hierarchy).

Zelikin, M. I.

2006-02-01

273

Rational Industrial Water Reuse Ratios  

NASA Astrophysics Data System (ADS)

This work begins by defining rational water use, and then discusses important factors that most strongly influence it. A general model is then developed to enable factories to quantify the ratio of rational industrial water reuse based on the least cost method. The model is established to minimize the cost of water with reference to gross water use and three subsystems - the intake, reuse, and discharge of industrial water. Discharge cost is determined using data from a 1997 survey of 38 factories, and reuse costs are ranked and expressed by a step function. The model is verified using data from a typical semiconductor factory in northern Taiwan's Hsinchu Science Based Industrial Park, whose effective rational water reuse ratio is about 38 percent. A sensitivity analysis shows that improving water reuse technology is the most important factor in determining the rational water reuse ratio, and the price of water is the second most important. When water costs over NT30 (New Taiwan Dollar, US1 = NT$34) per cubic meter, increasing reuse becomes significant. The model provides a step towards the scientific management of industrial water.

Liaw, Chao-Hsien; Chen, Liang-Ching

2004-08-01

274

Some Effects of Frequency on the Contribution of a Vertical Tail to the Free Aerodynamic Damping of a Model Oscillating in Yaw  

NASA Technical Reports Server (NTRS)

The damping in yaw and the directional stability of a model freely oscillating in yaw were measured tail-off and tail-on and compared with the values obtained by theoretical consideration of the unsteady lift associated with an oscillating vertical tail. A range of low frequencies comparable to those of the lateral motions of airplanes was covered. The analysis includes the effects of vertical-tail aspect ratio and the two-dimensional effects of compressibility.

Bird, John D; Fisher, Lewis R; Hubbard, Sadie M

1953-01-01

275

Bulk vertical micromachining of single-crystal sapphire using inductively coupled plasma etching for x-ray resonant cavities  

NASA Astrophysics Data System (ADS)

To provide coherent x-ray sources for probing the dynamic structures of solid or liquid biological substances on the picosecond timescale, a high-aspect-ratio x-ray resonator cavity etched from a single crystal substrate with a nearly vertical sidewall structure is required. Although high-aspect-ratio resonator cavities have been produced in silicon, they suffer from unwanted multiple beam effects. However, this problem can be avoided by using the reduced symmetry of single-crystal sapphire in which x-ray cavities may produce a highly monochromatic transmitted x-ray beam. In this study, we performed nominal 100?µm deep etching and vertical sidewall profiles in single crystal sapphire using inductively coupled plasma (ICP) etching. The large depth is required to intercept a useful fraction of a stopped-down x-ray beam, as well as for beam clearance. An electroplated Ni hard mask was patterned using KMPR 1050 photoresist and contact lithography. The quality and performance of the x-ray cavity depended upon the uniformity of the cavity gap and therefore verticality of the fabricated vertical sidewall. To our knowledge, this is the first report of such deep, vertical etching of single-crystal sapphire. A gas mixture of Cl2/BCl3/Ar was used to etch the sapphire with process variables including BCl3 flow ratio and bias power. By etching for 540?min under optimal conditions, we obtained an x-ray resonant cavity with a depth of 95?µm, width of ~30?µm, gap of ~115?µm and sidewall profile internal angle of 89.5°. The results show that the etching parameters affected the quality of the vertical sidewall, which is essential for good x-ray resonant cavities.

Chen, P.-C.; Lin, P.-T.; Mikolas, D. G.; Tsai, Y.-W.; Wang, Y.-L.; Fu, C.-C.; Chang, S.-L.

2015-01-01

276

Vertical Isolation for Photodiodes in CMOS Imagers  

NASA Technical Reports Server (NTRS)

In a proposed improvement in complementary metal oxide/semi conduct - or (CMOS) image detectors, two additional implants in each pixel would effect vertical isolation between the metal oxide/semiconductor field-effect transistors (MOSFETs) and the photodiode of the pixel. This improvement is expected to enable separate optimization of the designs of the photodiode and the MOSFETs so as to optimize their performances independently of each other. The purpose to be served by enabling this separate optimization is to eliminate or vastly reduce diffusion cross-talk, thereby increasing sensitivity, effective spatial resolution, and color fidelity while reducing noise.

Pain, Bedabrata

2008-01-01

277

Determination of vertical and horizontal wavelengths of gravity waves  

NASA Technical Reports Server (NTRS)

The determination of horizontal and vertical wavelengths of gravity waves obviously relies on measurement of wave parameters in horizontal and vertical directions. A very suitable parameter, measured fairly easily with MST radars, is the fluid velocity. Average velocities and superimposed turbulent fluctuations are much larger in the horizontal than in the vertical direction. Vertical and horizontal fluid velocities due to wave-like events are mostly about equal in magnitude. Vertical fluid velocities due to waves therefore can be more reliably detected than horizontal velocities. Estimates of gravity wave events using MST radar data are calculated and results are indicated.

Rottger, J.

1983-01-01

278

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

NASA Astrophysics Data System (ADS)

The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL-1) on the NASA B200 aircraft has acquired large datasets of aerosol extinction (532nm), backscatter (532 and 1064nm), and depolarization (532 and 1064nm) profiles during 349 science flights in 19 field missions across North America since 2006. The extinction-to-backscatter ratio ("lidar ratio"), aerosol depolarization ratios, and backscatter color ratio measurements from HSRL-1 are scale-invariant parameters that depend on aerosol type but not concentration. These four aerosol intensive parameters are combined to qualitatively classify HSRL aerosol measurements into eight separate composition types. The classification methodology uses models formed from "training cases" with known aerosol type. The remaining measurements are then compared with these models using the Mahalanobis distance. Aerosol products from the CALIPSO satellite include aerosol type information as well, which is used as input to the CALIPSO aerosol retrieval. CALIPSO aerosol types are inferred using a mix of aerosol loading-dependent parameters, estimated aerosol depolarization, and location, altitude, and surface type information. The HSRL instrument flies beneath the CALIPSO satellite orbit track, presenting the opportunity for comparisons between the HSRL aerosol typing and the CALIPSO Vertical Feature Mask Aerosol Subtype product, giving insight into the performance of the CALIPSO aerosol type algorithm. We find that the aerosol classification from the two instruments frequently agree for marine aerosols and pure dust, and somewhat less frequently for pollution and smoke. In addition, the comparison suggests that the CALIPSO polluted dust type is overly inclusive, encompassing cases of dust combined with marine aerosol as well as cases without much evidence of dust. Qualitative classification of aerosol type combined with quantitative profile measurements of aerosol backscatter and extinction has many useful applications. The HSRL products are used to apportion AOT by type and vertical location in the column, and to characterize the frequency of cases where multiple types are present in the column. Resolving scenes with multiple types in the column is not possible with passive imaging radiometer and polarimeter measurements. The HSRL aerosol type also has higher resolution than the CALIPSO layer-wise product and provides insight into the performance of CALIPSO layer separation. Information about the vertical distribution of aerosol types is useful for estimating radiative forcing, understanding aerosol lifetime and transport, and assessing the predictions of transport models. CALIPSO has been a pathfinder, providing the first long-term global data set of aerosol vertical distribution. Based on our results, a future satellite lidar similar to CALIPSO, but with the addition of polarization sensitivity at 1064 nm and the HSRL technique at 532 nm, could provide a significant advance in characterizing the vertical distribution of aerosol.

Burton, S. P.; Ferrare, R. A.; Omar, A. H.; Hostetler, C. A.; Hair, J. W.; Rogers, R.; Obland, M. D.; Butler, C. F.; Cook, A. L.; Harper, D. B.

2012-12-01

279

Envera Variable Compression Ratio Engine  

SciTech Connect

Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy has already demonstrated a degree of success, downsizing and fuel economy gains are currently limited. With new variable compression ratio technology however, the degree of engine downsizing and fuel economy improvement can be greatly increased. A small variable compression ratio (VCR) engine has the potential to return significantly higher vehicle fuel economy while also providing high power. Affordability and potential for near term commercialization are key attributes of the Envera VCR engine. VCR Technology To meet torque and power requirements, a smaller engine needs to do more work per stroke. This is typically accomplished by boosting the incoming charge with either a turbo or supercharger so that more energy is present in the cylinder per stroke to do the work. With current production engines the degree of engine boosting (which correlates to downsizing) is limited by detonation (combustion knock) at high boost levels. Additionally, the turbo or supercharger needs to be responsive and efficient while providing the needed boost. VCR technology eliminates the limitation of engine knock at high load levels by reducing compression ratio to {approx}9:1 (or whatever level is appropriate) when high boost pressures are needed. By reducing the compression ratio during high load demand periods there is increased volume in the cylinder at top dead center (TDC) which allows more charge (or energy) to be present in the cylinder without increasing the peak pressure. Cylinder pressure is thus kept below the level at which the engine would begin to knock. When loads on the engine are low the compression ratio can be raised (to as much as 18:1) providing high engine efficiency. It is important to recognize that for a well designed VCR engine cylinder pressure does not need to be higher than found in current production turbocharged engines. As such, there is no need for a stronger crankcase, bearings and other load bearing parts within the VCR engine. The Envera VCR mechanism uses an eccentric carrier approach to adjust engine compression ratio. The crankshaft main bearings are mounted in this eccentric carrier or 'crankshaft cradle' and pivoting the eccentric carrier 30 degrees adjusts compression ratio from 9:1 to 18:1. The eccentric carrier is made up of a casting that provides rigid support for the main bearings, and removable upper bearing caps. Oil feed to the main bearings transits through the bearing cap fastener sockets. The eccentric carrier design was chosen for its low cost and rigid support of the main bearings. A control shaft and connecting links are used to pivot the eccentric carrier. The control shaft mechanism features compression ratio lock-up at minimum and maximum compression ratio settings. The control shaft method of pivoting the eccentric carrier was selected due to its lock-up capability. The control shaft can be rotated by a hydraulic actuator or an electric motor. The engine shown in Figures 3 and 4 has a hydraulic actuator that was developed under the current program. In-line 4-cylinder engines are significantly less expensive than V engines because an entire cylinder head can be eliminated. The cost savings from eliminating cylinders and an entire cylinder head will notably offset the added cost of the VCR and supercharging. Replacing V6 and V8 engines with in-line VCR 4-cylinder engines will provide high fuel economy at low cost. Numerous enabling technologies exist which have the potential to increase engine efficiency. The greatest efficiency gains are realized when the right combination of advanced and new technologies are packaged together to provide the greatest gains at the least cost. Aggressive engine downsiz

Charles Mendler

2011-03-15

280

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

281

Two-stage epitaxial growth of vertically-aligned SnO2 nano-rods on (001) ceria  

NASA Astrophysics Data System (ADS)

Growth of high-aspect ratio oriented tin oxide, SnO2, nano-rods is complicated by a limited choice of matching substrates. We show that a (001) cerium oxide, CeO2, surface uniquely enables epitaxial growth of tin-oxide nano-rods via a two-stage process. First, (100) oriented nano-wires coat the ceria surface by lateral growth, forming a uniaxially-textured SnO2 deposit. Second, vertical SnO2 nano-rods nucleate on the deposit by homoepitaxy. We demonstrate growth of vertically oriented 1-2 ?m long nano-rods with an average diameter of ?20 nm.

Solovyov, Vyacheslav F.; Wu, Li-jun; Rupich, Martin W.; Sathyamurthy, Srivatsan; Li, Xiaoping; Li, Qiang

2014-12-01

282

Mass Spectrometry in Jupiter's Atmosphere: Vertical Variation of Volatile Vapors  

NASA Astrophysics Data System (ADS)

The Galileo Probe made the first and only in situ measurements of composition in Jupiter's atmosphere, led by the Galileo Probe Mass Spectrometer, or GPMS [1]. The major contribution from this instrument was the measurement of abundances and isotope ratios of the noble gases, as well as the volatile gases CH4, NH3, H2O, and H2S [2,3]. These initial results were further refined by detailed laboratory calibrations for the noble gases [4] and the volatiles [5]. The probe measurements resulted in the first determination of the heavy element abundances (except carbon that was known previously) and He/H ratio, which provide critical constraints to models of the formation of Jupiter and the origin of its atmosphere [6,7]. The condensable volatiles, or CVs (ammonia, H2S, and water), increased with depth in the probe entry site. This vertical variation was observed at levels much deeper than the modeled cloud bases, as predicted by one-dimensional chemical equilibrium models. The discrepancy is due to the probe's entry into a dry region known as a 5-?m hot spot. The 5-?m hot spots are part of an atmospheric wave system that encircles Jupiter just north of the equator. Despite the anomalous meteorology, the bulk abundances of NH3 and H2S were measured by the probe, and found to be enriched with respect to solar composition (similarly to the non-condensable volatile CH4). The deepest water mixing ratio, however, was observed to be depleted relative to solar composition. We review an updated context for the CV vertical profiles measured by the GPMS, based on the latest results from remote sensing, simulation, and reinterpretation of Galileo Probe measurements. In particular, we find that (1) the bulk abundance of water in Jupiter's atmosphere must be greater than the subsolar abundance derived from the deepest GPMS measurements [8], and that (2) CV mixing ratios are controlled by a range of processes in addition to condensation of the ices NH3, NH4SH, and H2O [5-9]. Both bulk abundances and spatial variation of these species will be further constrained by the Juno mission, scheduled to arrive at Jupiter in 2016. References: [1] Niemann, H.B. et al. 1992, SSRv 60, 111-142 [2] Niemann, H.B. et al. 1996, Science 272, 846-849 [3] Niemann, H.B. et al. 1998, JGR 103, 22831-22845 [4] Mahaffy, P.R. et al. 2000, JGR 105, 15061-15071 [5] Wong, M.H. et al. 2004, Icarus 171, 153-170 [6] Atreya, S.K. et al., 1999, Planet. Space Sci. 47, 1243-1262 [7] Atreya, S.K. et al., 2003, Planet. Space Sci. 451, 105-112 [8] Wong, M.H. et al., 2008, in Reviews in Mineralogy and Geochemistry, vol. 68. Mineralogical Society of America, Chantilly, VA, pp. 219-246 [9] Wong, M.H., 2009, Icarus 199, 231-235

Wong, Michael H.; Atreya, Sushil K.; Mahaffy, Paul R.

2014-05-01

283

Charge-to-mass ratio of saltating particles in wind-blown sand.  

PubMed

The electrification of sand particles plays an important role in aeolian events. In this paper, the charge-to-mass ratio vertical profiles of saltating particles in wind-blown sand were measured by a field experiments. By combining the results of field measurements with our previous wind-tunnel measurements, we discussed the factors affecting the charge-to-mass ratio of saltating particles. It reveals that the magnitude of the charge-to-mass ratio increases exponentially with height above the surface. In addition, the charge polarity of saltating particles depends on the relative size between saltating and creeping particles, and the magnitude of charge-to-mass ratio is determined by wind velocity and the relative size difference ratio between saltating and creeping particles. PMID:24998641

Bo, Tian-Li; Zhang, Huan; Zheng, Xiao-Jing

2014-01-01

284

Charge-to-mass Ratio of Saltating Particles in Wind-Blown Sand  

NASA Astrophysics Data System (ADS)

The electrification of sand particles plays an important role in aeolian events. In this paper, the charge-to-mass ratio vertical profiles of saltating particles in wind-blown sand were measured by a field experiments. By combining the results of field measurements with our previous wind-tunnel measurements, we discussed the factors affecting the charge-to-mass ratio of saltating particles. It reveals that the magnitude of the charge-to-mass ratio increases exponentially with height above the surface. In addition, the charge polarity of saltating particles depends on the relative size between saltating and creeping particles, and the magnitude of charge-to-mass ratio is determined by wind velocity and the relative size difference ratio between saltating and creeping particles.

Bo, Tian-Li; Zhang, Huan; Zheng, Xiao-Jing

2014-07-01

285

Diagnosis of vertical motion from VAS retrievals  

NASA Technical Reports Server (NTRS)

Satellite-derived temperature profiles are used to determine if reliable estimates of synoptic-scale vertical motion can be obtained from the adiabatic, vorticity, and omega equation techniques. The period of study contains a short-wave trough over the Midwest and a convective outbreak over the middle Mississippi River Valley. Satellite soundings are available at 1-3 h intervals at five times. The emphasis is on assessing the strengths and weaknesses of the three vertical motion procedures, and determining the effects of short-interval observations on the calculations. Results show that the quasi-geostrophic omega equation provided patterns and magnitudes most consistent with observed weather events and 12 h radiosonde-derived motions. The vorticity method produced less satisfactory results, while adiabatic motions were unacceptable. The time derivative term dominated adiabatic motions and was a major influence in the vorticity method. Unrealistic temperature tendencies resulted from the retrieval algorithm; i.e., a diurnal temperature bias extended upwards to 500 mb, and there was a compensating effect at higher levels.

Fuelberg, Henry E.; Funk, Theodore W.

1987-01-01

286

Fracture characterization from vertical seismic profiling data  

NASA Astrophysics Data System (ADS)

In vertical seismic profiling (VSP) data, large-amplitude borehole Stoneley waves are observed at depths where fractures intersect the borehole. We present a model which predicts the amplitudes of these Stoneley waves as a function of certain parameters of the fractures, namely, the fracture aperture (width), the orientation, and the degree of stiffness and roughness of the fracture. The proposed mechanism for the generation of these borehole Stoneley waves is coupling of a guided mode, induced in the fracture by an incident plane wave (typically a P wave), to the borehole. The model expresses the borehole Stoneley wave amplitude, normalized by the amplitude of the direct P wave, as a function of frequency, in terms of the fracture parameters. The model is used as the basis for an inversion scheme, employing a nonlinear least squares algorithm to estimate the fracture parameters. The inversion is then applied to VSP data where borehole Stoneley waves are observed at depths where fractures are known to intersect the borehole. The results of the inversion indicate that the aperture and vertical component of the orientation (i.e., dip) of the fracture can be accurately estimated but the horizontal component of the orientation (i.e., strike) is not well resolved.

Cicerone, Robert D.; Toksoz, M. Nafi

1995-03-01

287

Trends in the Vertical Distribution of Ozone  

NASA Technical Reports Server (NTRS)

Analyses of satellite, ground-based, and balloon measurements allow updated estimates of trends in the vertical profile of ozone since 1979. The results show overall consistency among several independent measurement systems, particularly for northern hemisphere midlatitudes where most balloon and ground-based measurements are made. Combined trend estimates over these latitudes for the period 1979-96 show statistically significant negative trends at all attitudes between 10 and 45 km, with two local extremes: -7.4 +/- 2.0% per decade at 40 km and -7.3 +/- 4.6% per decade at 15 km attitude. There is a strong seasonal variation in trends over northern midlatitudes in the attitude range of 10 to 18 km. with the largest ozone loss during winter and spring. The profile trends are in quantitative agreement with independently measured trends in column ozone, the amount of ozone in a column above the surface. The vertical profiles of ozone trends provide a fingerprint for the mechanisms of ozone depletion over the last two decades,

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

2002-01-01

288

Trends in the Vertical Distribution of Ozone  

NASA Technical Reports Server (NTRS)

Analyses of satellite, ground-based, and balloon measurements allow updated estimates of trends in the vertical profile of ozone since 1979. The results show overall consistency among several independent measurement systems, particularly for northern hemisphere midlatitudes where most balloon and ground-based measurements are made. Combined trend estimates over these latitudes for the period 1979-96 show statistically significant negative trends at ail attitudes between 10 and 45 km, with two local extremes: -7.4 +/- 2.0% per decade at 40 km and -7.3 +/- 4.6% per decade at 15 km attitude. There is a strong seasonal variation in trends over northern midlatitudes in the altitude range of 10 to 18 km, with the largest ozone loss during winter and spring. The profile trends are in quantitative agreement with independently measured trends in column ozone, the amount of ozone in a column above the surface. The vertical profiles of ozone trends provide a fingerprint for the mechanisms of ozone depletion over the last two decades.

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

1999-01-01

289

Trends in the Vertical Distribution of Ozone  

NASA Technical Reports Server (NTRS)

Analyses of satellite, ground-based, and balloon measurements allow updated estimates of trends in the vertical profile of ozone since 1979. The results show overall consistency among several independent measurement systems, particularly for northern hemisphere midlatitudes where most balloon and ground-based measurements are made. Combined trend estimates over these latitudes for the period 1979-96 show statistically significant negative trends at all altitudes between 10 and 45 km, with two local extremes: -7.4 plus or minus 2.0% per decade at 40 km and -7.3 plus or minus -4.6% per decade at 15 km altitude. There is a strong seasonal variation in trends over northern midlatitudes in the attitude range of 10 to 18 km, with the largest ozone loss during winter and spring. The profile trends are in quantitative agreement with independently measured trends in column ozone, the amount of ozone in a column above the surface. The vertical profiles of ozone trends provide a fingerprint for the mechanisms of ozone depletion over the last two decades.

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

1999-01-01

290

Trends in the vertical distribution of ozone  

PubMed

Analyses of satellite, ground-based, and balloon measurements allow updated estimates of trends in the vertical profile of ozone since 1979. The results show overall consistency among several independent measurement systems, particularly for northern hemisphere midlatitudes where most balloon and ground-based measurements are made. Combined trend estimates over these latitudes for the period 1979-96 show statistically significant negative trends at all altitudes between 10 and 45 km, with two local extremes: -7.4 +/- 2. 0% per decade at 40 km and -7.3 +/- 4.6% per decade at 15 km altitude. There is a strong seasonal variation in trends over northern midlatitudes in the altitude range of 10 to 18 km, with the largest ozone loss during winter and spring. The profile trends are in quantitative agreement with independently measured trends in column ozone, the amount of ozone in a column above the surface. The vertical profiles of ozone trends provide a fingerprint for the mechanisms of ozone depletion over the last two decades. PMID:10480999

Randel; Stolarski; Cunnold; Logan; Newchurch; Zawodny

1999-09-10

291

Control system for a vertical axis windmill  

DOEpatents

A vertical axis windmill having a rotating structure is provided with a series of articulated vertical blades whose positions are controlled to maintain a constant RPM for the rotating structure, when wind speed is sufficient. A microprocessor controller is used to process information on wind speed, wind direction and RPM of the rotating structure to develop an electrical signal for establishing blade position. The preferred embodiment of the invention, when connected to a utility grid, is designed to generate 40 kilowatts of power when exposed to a 20 mile per hour wind. The control system for the windmill includes electrical blade actuators that modulate the blades of the rotating structure. Blade modulation controls the blade angle of attack, which in turn controls the RPM of the rotor. In the preferred embodiment, the microprocessor controller provides the operation logic and control functions. A wind speed sensor provides inputs to start or stop the windmill, and a wind direction sensor is used to keep the blade flip region at 90.degree. and 270.degree. to the wind. The control system is designed to maintain constant rotor RPM when wind speed is between 10 and 40 miles per hour.

Brulle, Robert V. (St. Louis County, MO)

1983-10-18

292

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

293

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

294

High vertical resolution crosswell seismic imaging  

DOEpatents

A method for producing high vertical resolution seismic images from crosswell data is disclosed. In accordance with one aspect of the disclosure, a set of vertically spaced, generally horizontally extending continuous layers and associated nodes are defined within a region between two boreholes. The specific number of nodes is selected such that the value of a particular characteristic of the subterranean region at each of the nodes is one which can be determined from the seismic data. Once values are established at the nodes, values of the particular characteristic are assigned to positions between the node points of each layer based on the values at node within that layer and without regard to the values at node points within any other layer. A seismic map is produced using the node values and the assigned values therebetween. In accordance with another aspect of the disclosure, an approximate model of the region is established using direct arrival traveltime data. Thereafter, the approximate model is adjusted using reflected arrival data. In accordance with still another aspect of the disclosure, correction is provided for well deviation. An associated technique which provides improvements in ray tracing is also disclosed.

Lazaratos, Spyridon K. (Houston, TX)

1999-12-07

295

Adaptive focusing - The likelihood ratio  

NASA Astrophysics Data System (ADS)

The problem of detecting a certain non-Gaussian random acoustic signal field in a spatially white Gaussian noise field is solved within the formalism of classical detection theory. Two solutions of the problem are compared: the maximum-likelihood or adaptive-focusing receiver and the Neyman-Pearson or adaptive focusing optimal (AFO) receiver. Based on two criteria for comparison, it is found that the two receivers differ only slightly in performance, with the AFO, of course, being the better. One of the criteria is based on the signal deflection ratio, and the other is the receiver operating characteristic curve. The comparisons are done for a Monte Carlo simulation.

Labianca, F. M.; Lloyd, S. P.

1981-08-01

296

Association of drop vertical jump displacement with select performance variables.  

PubMed

Drop vertical jumps (DVJs) stimulate enhanced countermovement loading as would occur with a run-up before jumping. A variety of performance variables have been associated with DVJ performance including ground contact time (GCT), reactive strength index (RSI), eccentric utilization ratio (EUR), and elasticity index (EI). This study examined the stability reliability and precision of these variables and their associations with DVJ displacement in trained men and women. The EUR and EI measures were redundant, so only EUR findings were reported. Except for EUR, data for all variables were both reliable and precise (intraclass correlation coefficient ? 0.70, coefficient of variation [CV%] ? 15.0) although EUR data were precise (CV% ? 15.0). Correlations with DVJ displacement were low for GCT, moderate for RSI, and negligible for EUR. Therefore, GCT and EUR likely represent unique performance characteristics not related to DVJ displacement. Furthermore, the variability in DVJ performance accounted for by RSI may primarily reflect the inclusion of displacement as the numerator in the quotient for calculating it. PMID:22228173

Feldmann, Christina R; Weiss, Lawrence W; Schilling, Brian K; Whitehead, Paul N

2012-05-01

297

Transition between Atomic and Molecular Hydrogen in the Galaxy: Vertical Variation of the Molecular Fraction  

E-print Network

We derive radial and vertical distributions of HI and H2 gas densities in our Galaxy by using the terminal velocity method. We calculate the molecular fraction (f_mol) defined as the ratio of the molecular hydrogen to total hydrogen gas density at galactic longitude l= 33 to 64 deg and galactic latitude b=-2 to +2 deg. The thickness of the molecular dominant region f_mol > 0.8 is approximately constant (109 +/- 12 pc) at galactocentric distance R = 4.7 to 7.2 kpc. The molecular fraction decreases suddenly at a critical height from the galactic plane, below which the gas disk is almost totally molecular, while it is almost atomic beyond this height. We show that the vertical f_mol variation can be reproduced by a model which takes into account the phase transition between HI and H2 gases in the interstellar matter. Key words: Atomic Hydrogen --- the Galaxy --- Interstellar Matter --- Molecular Hydrogen

K. Imamura; Y. Sofue

1996-07-08

298

Large current modulation and spin-dependent tunneling of vertical graphene/MoS2 heterostructures.  

PubMed

Vertical graphene heterostructures have been introduced as an alternative architecture for electronic devices by using quantum tunneling. Here, we present that the current on/off ratio of vertical graphene field-effect transistors is enhanced by using an armchair graphene nanoribbon as an electrode. Moreover, we report spin-dependent tunneling current of the graphene/MoS2 heterostructures. When an atomically thin MoS2 layer sandwiched between graphene electrodes becomes magnetic, Dirac fermions with different spins feel different heights of the tunnel barrier, leading to spin-dependent tunneling. Our finding will develop the present graphene heterostructures for electronic devices by improving the device performance and by adding the possibility of spintronics based on graphene. PMID:23886348

Myoung, Nojoon; Seo, Kyungchul; Lee, Seung Joo; Ihm, G

2013-08-27

299

Satellite remote sensing and ozonesonde observation of ozone vertical profile and severe storm development  

NASA Technical Reports Server (NTRS)

Two year ozonesonde data, January 1981 to December 1982, observed at four Canadian stations, and two-and-a-half year backscattered ultraviolet experiment data on the Nimbus-4 satellite, April 1970 to August 1972, observed over five U.S. stations, were used to study the relationship between the total ozone, vertical distribution of the ozone mixing ratio, height of half the total ozone, and the variation of local tropopause height. In view of the correlation between the variation of the tropopause height and the possible development of severe storms, a better understanding of the effect of the vertical distribution of the local ozone profile on the variation of the tropopause height can give considerable insight into the development of severe storms.

Hung, R. J.; Liu, J. M.

1988-01-01

300

Bifurcation and stability of low-order steady flows in horizontally and vertically forced convection  

NASA Technical Reports Server (NTRS)

A nonlinear spectral model of two-dimensional, shallow Boussinesq convection which responds to heating in both the horizontal and vertical directions is examined. The governing partial differential system is converted to an infinite set of ordinary differential equations and truncated to a small set to permit detailed study of the number and types of transitions from one flow configuration to another. The Hadley number and the Rayleigh number are defined as the horizontal and vertical thermal forcing mechanisms, respectively, for inclusion in the nonlinear spectral model, which is composed of three equations. The model is then used to describe steady states, linearly stable solutions, and balancing factors in unstable stratification. The number and the distribution of the steady states are found to be qualitatively independent of the aspect ratio and the Prandtl number.

Yost, D. A.; Shirer, H. N.

1982-01-01

301

High-aspect-ratio wings  

NASA Technical Reports Server (NTRS)

High-aspect-ratio aircraft include most transport aircraft such as commercial and military transports, business aircraft, and cargo aircraft. Generally, these types of aircraft are designed to cruise over a narrow range of lift coefficients and Mach numbers in the performance of their mission. Emphasis is therefore placed on the cruise performance of transport aircraft and every effort is made to obtain accurate wind-tunnel data to use as a basis for prediction of full-scale cruise performance. However, off-cruise performance is also important and methods were developed for extrapolating wind-tunnel data on buffet and flutter at transonic speed. Transport-type aircraft were tested extensively in various wind tunnels around the world and many different test techniques were developed to simulate higher Reynolds numbers. Methods developed for one tunnel may not be applicable to another tunnel because of differences in size, Reynolds number capability, running time, and test objectives. Many of the methods of boundary-layer control developed in two-dimensional airfoil testing can be applied in tests of transport configurations, but sometimes the three-dimensional flow fields that develop on tranpsort aircraft can make application of the two-dimensional methods difficult or impossible. The discussion is intended to be a representative, but not exhaustive, survey of the various methods of high Reynolds number simulation in the testing of high-aspect-ratio aircraft.

Peterson, John B., Jr.

1988-01-01

302

Velocity structure in upper ocean crust at Hole 504B from vertical seismic profiles  

NASA Astrophysics Data System (ADS)

Hole 504B provides the only opportunity to directly correlate seismic velocity structure to the lithology and physical properties of upper ocean crust, providing a baseline for comparison with seismic measurements elsewhere. We determine P and S velocities from vertical seismic profiles (VSPs) obtained on Ocean Drilling Program (ODP) Legs 111 and 148. Four issues are considered: the location of the seismic layer 2/3 boundary, P to S wave conversion by scattering, transverse isotropy, and Poisson's ratio as an indicator of lithology, porosity, and structure. (1) In the P velocity profile, the change in slope marking the layer 2/3 boundary coincides with the top of the sheeted dike unit. Seismic layer 2 is composed of the extrusives and the lithologic transition zone, the layer in which flows and dikes interfinger. (2) Even in these normal incident VSPs, several second arrivals with velocities indicative of vertically polarized shear energy are observed. P to S wave conversion within the upper 110 m of basement occurs by scattering from surface roughness and volume heterogeneities and does not depend on angle of incidence as predicted by plane boundary transmission coefficient analysis. (3) Vertical velocities determined from the VSP differ by <10% from horizontal velocities obtained from the oblique seismic experiment (OSE) on Deep Sea Drilling Project (DSDP) Leg 92. The P wave velocity structure is determined by small and intermediate (<1 cm) pore structure with no measurable anisotropy. The large-scale, well-oriented vertical fractures, which are formed tectonically, do not have a detectable effect on compressional wave velocities. (4) High Poisson's ratio in the upper 300 m of basement coincides with an extrusive layer composed of pillows and thin flows. Low Poisson's ratio at 850-1150 m below seafloor (mbsf) coincides with the downhole decrease in bulk porosity caused by the transition from extrusives to dikes. Relatively large-aspect ratio cracks are required to produce such low values of Poisson's ratio. The cracks were likely created by hydraulic fracturing when hot dikes encountered low-temperature seawater.

Swift, Stephen A.; Lizarralde, D.; Stephen, Ralph A.; Hoskins, Hartley

1998-07-01

303

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

304

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

NASA Technical Reports Server (NTRS)

We use CALIOP nighttime measurements of lidar backscatter, color and depolarization ratios, as well as particulate retrievals during the summer of 2007 to study transatlantic dust properties downwind of Saharan sources, and to examine the influence of nearby clouds on dust. Our analysis suggests that (1) under clear skies, while lidar backscatter and color ratio do not change much with altitude and longitude in the Saharan Air Layer (SAL), depolarization ratio increases with altitude and decreases westward in the SAL (2) the vertical lapse rate of dust depolarization ratio, introduced here, increases within SAL as plumes move westward (3) nearby clouds barely affect the backscatter and color ratio of dust volumes within SAL but not so below SAL. Moreover, the presence of nearby clouds tends to decrease the depolarization of dust volumes within SAL. Finally, (4) the odds of CALIOP finding dust below SAL next to clouds are about of those far away from clouds. This feature, together with an apparent increase in depolarization ratio near clouds, indicates that particles in some dust volumes loose 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.

2014-01-01

305

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

306

Influence of running velocity on vertical, leg and joint stiffness : modelling and recommendations for future research.  

PubMed

Human running can be modelled as either a spring-mass model or multiple springs in series. A force is required to stretch or compress the spring, and thus stiffness, the variable of interest in this paper, can be calculated from the ratio of this force to the change in spring length. Given the link between force and length change, muscle stiffness and mechanical stiffness have been areas of interest to researchers, clinicians, and strength and conditioning practitioners for many years. This review focuses on mechanical stiffness, and in particular, vertical, leg and joint stiffness, since these are the only stiffness types that have been directly calculated during human running. It has been established that as running velocity increases from slow-to-moderate values, leg stiffness remains constant while both vertical stiffness and joint stiffness increase. However, no studies have calculated vertical, leg or joint stiffness over a range of slow-to-moderate values to maximum values in an athletic population. Therefore, the effects of faster running velocities on stiffness are relatively unexplored. Furthermore, no experimental research has examined the effects of training on vertical, leg or joint stiffness and the subsequent effects on running performance. Various methods of training (Olympic style weightlifting, heavy resistance training, plyometrics, eccentric strength training) have shown to be effective at improving running performance. However, the effects of these training methods on vertical, leg and joint stiffness are unknown. As a result, the true importance of stiffness to running performance remains unexplored, and the best practice for changing stiffness to optimize running performance is speculative at best. It is our hope that a better understanding of stiffness, and the influence of running speed on stiffness, will lead to greater interest and an increase in experimental research in this area. PMID:18620465

Brughelli, Matt; Cronin, John

2008-01-01

307

Factors determining the vertical profile of dimethylsulfide in the Sargasso Sea during summer  

NASA Astrophysics Data System (ADS)

The major source of reduced sulfur in the remote marine atmosphere is the biogenic compound dimethylsulfide (DMS), which is ubiquitous in the world's oceans and released through food web interactions. Relevant fluxes and concentrations of DMS, its phytoplankton-produced precursor, dimethylsulfoniopropionate (DMSP) and related parameters were measured during an intensive Lagrangian field study in two mesoscale eddies in the Sargasso Sea during July-August 2004, a period characterized by high mixed-layer DMS and low chlorophyll—the so-called 'DMS summer paradox'. We used a 1-D vertically variable DMS production model forced with output from a 1-D vertical mixing model to evaluate the extent to which the simulated vertical structure in DMS and DMSP was consistent with changes expected from field-determined rate measurements of individual processes, such as photolysis, microbial DMS and dissolved DMSP turnover, and air-sea gas exchange. Model numerical experiments and related parametric sensitivity analyses suggested that the vertical structure of the DMS profile in the upper 60 m was determined mainly by the interplay of the two depth-variable processes—vertical mixing and photolysis—and less by biological consumption of DMS. A key finding from the model calibration was the need to increase the DMS(P) algal exudation rate constant, which includes the effects of cell rupture due to grazing and cell lysis, to significantly higher values than previously used in other regions. This was consistent with the small algal cell size and therefore high surface area-to-volume ratio of the dominant DMSP-producing group—the picoeukaryotes.

Gabric, A. J.; Matrai, P. A.; Kiene, R. P.; Cropp, R.; Dacey, J. W. H.; DiTullio, G. R.; Najjar, R. G.; Simó, R.; Toole, D. A.; delValle, D. A.; Slezak, D.

2008-05-01

308

Vertical profiles of halocarbons in the stratosphere  

SciTech Connect

Stratospheric air samples collected between 10 and 35 km altitude by means of a cryogenic sampler were analyzed by gaschromatography. Thus vertical profiles of source gases for halogen radicals were derived, such as CCl4, CCl3F, CCl2F2, CClF3, CF4, C2F3Cl3, C2F4Cl2, C2F5Cl, C2F6, CH3Cl, CH3CCl3, CHF2Cl, CH3Br, CBrF3, and CBrCl2F. Systematic discrepancies between measured and modelled halocarbon profiles point to deficiencies of present one- and two-dimensional models. Measurements of fully halogenated hydrocarbons provide a tool for systematically studying these deficiencies and thus improving the models. 40 references.

Fabian, P.; Borchers, R.

1984-01-01

309

Track of Right-Wheel Drag (Vertical)  

NASA Technical Reports Server (NTRS)

This 360-degree panorama combines several frames taken by the navigation camera on NASA's Mars Exploration Rover Spirit during the rover's 313th martian day (Nov. 19, 2004). The site, labeled Spirit site 93, is in the 'Columbia Hills' inside Gusev Crater. The rover tracks point westward. Spirit had driven eastward, in reverse and dragging its right front wheel, for about 30 meters (100 feet) on the day the picture was taken. Driving backwards while dragging that wheel is a precautionary strategy to extend the usefulness of the wheel for when it is most needed, because it has developed more friction than the other wheels. The right-hand track in this look backwards shows how the dragging disturbed the soil. This view is presented in a vertical projection with geometric seam correction.

2004-01-01

310

[The hyoid bone and vertical dimension].  

PubMed

Located at the center of the neck and the pharyngeal column and, thanks to its attachments, tied to the base of the skull, to the mandible, to the tongue, to the larynx, and to the scapular belt, the hyoid bone is intimately related to an extensive tendino-muscular complex. From this strategic position, the hyoid bone participates in all functional and nutritional activities of the oro-facial complex. Heavily involved in the physiology of the pharyngeal column, it appears to enjoy a remarkable stability in relation to its surrounding structures as it participates in the critical process of vertical ontogenetic development. Deceptively simple in its shape and location it is anything but. While it would be easy to scorn it as a vestigial organ of little importance, the hyoid bone is actually an ancient witness of the evolution of the first human vertebrae and a vestige of the 2nd and 3rd brachial arches. Like a toy buffeted by powerful groups of muscles and tendons, the hyoid bone occupies a crossroads position where it is solicited by many vital functions, the most critical of which is respiration. Its functional behavior seems to have evolved considerably over the course of phylogeny. By piecing together the conceptions of many authors, we can conclude that the similarities--and, later, the differences--existing between the human fetus and those of other primates, and, then between young children and young primates, are related to an essentially different status quo, which modifies the delicate equilibrium of the pharyngeal region. In metamorphosing from a sagittal equilibrium to one that is vertical, this very status quo maintains an open respiratory airway during each time frame, continuously permitting the articulation and modulation of sounds, particularly during the vertical period. The hyoid bone is unpaired, in a mid-line position, symmetrical, and located just below the mandible with which it shares, to an astonishing extent, certain morphological characteristics. Its maturation and its ossification occur slowly and late even though it migrates much more rapidly to a vertical position than does the bulk of the cervical complex. True articulations between the body and the horns of the hyoid bone persist for a very long time; and so the junction between the small horns doesn't fully calcify until about the age of 50; and, in spite of its appearance, the hyoid bone is extremely supple, a quality that allows it to make substantial contributions to functional activity. If the hyoid bone itself scarcely moves during normal respiration, modern research attributes an increasing role to it in the maintenance of the equilibrium of the pharyngeal column. It seems to be called upon to respond to a number of demands that it manages to satisfy as it helps to maintain the permeability of the pharyngeal column and thus make respiration possible. In so doing, the hyoid bone adjusts its positioning, and, perhaps most important, its orientation to the physiological requirements imposed by pharyngeal obstruction and mouth breathing. Intimately connected to the larynx, the hyoid bone plays a part in phonation that has long been recognized. Recent studies now also show that the contribution the hyoid bone makes to respiratory equilibrium is far more important than its small size would suggest. PMID:15301368

Doual, A; Léger, J L; Doual, J M; Hadjiat, F

2003-09-01

311

Multispectral imaging with vertical silicon nanowires.  

PubMed

Multispectral imaging is a powerful tool that extends the capabilities of the human eye. However, multispectral imaging systems generally are expensive and bulky, and multiple exposures are needed. Here, we report the demonstration of a compact multispectral imaging system that uses vertical silicon nanowires to realize a filter array. Multiple filter functions covering visible to near-infrared (NIR) wavelengths are simultaneously defined in a single lithography step using a single material (silicon). Nanowires are then etched and embedded into polydimethylsiloxane (PDMS), thereby realizing a device with eight filter functions. By attaching it to a monochrome silicon image sensor, we successfully realize an all-silicon multispectral imaging system. We demonstrate visible and NIR imaging. We show that the latter is highly sensitive to vegetation and furthermore enables imaging through objects opaque to the eye. PMID:23955156

Park, Hyunsung; Crozier, Kenneth B

2013-01-01

312

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

313

Tunable Ultraviolet Vertically-emitting Organic Laser  

E-print Network

A solid-state organic thin-film laser with intracavity frequency doubling is reported. Tunable ultraviolet emission from 309 to 322 nm is achieved from a vertical external cavity surface-emitting organic laser, with 2 % efficiency (1 $\\mu$J at 315 nm). The laser comprises a polymethyl(methacrylate) layer doped with Rhodamine 640, spun-cast onto a plane mirror, a remote concave mirror, a nonlinear crystal and a dichroic separator. The output is spectrally narrow (<0.5 nm FWHM) and tunable through phase-matching selection of the fundamental radiation lasing modes. These results highlight a low-cost and portable alternative to tunable UV laser sources, useful for spectroscopic applications.

Forget, Sebastien; Diffalah, Nordine; Siove, Alain; Chenais, Sebastien

2011-01-01

314

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

315

Dynamic soil pressures on rigid vertical walls  

SciTech Connect

A critical evaluation is made of the dynamic pressures and the associated forces induced by ground shaking on a rigid, straight, vertical wall retaining a semi-infinite, uniform viscoelastic layer of constant thickness. The effects of both harmonic and earthquake-induced excitations are examined. Simple approximate expressions for the responses of the system are developed, and comprehensive numerical data are presented which elucidate the effects and relative importance of the various parameters involved. These solutions are then compared with those obtained by use of a simple model proposed previously by Scott, and the accuracy of this model is assessed. Finally, two versions of an alternative model are proposed which better approximate the action of the system. In the first, the properties of the model are defined by frequency-dependent parameters, whereas in the second, which is particularly helpful in analyses of transient response, they are represented by frequency-independent, constant parameters.

Veletsos, A.S.; Younan, A.H. [Rice Univ., Houston, TX (United States)

1992-12-01

316

Aberrations of a horizontal-vertical depolarizer  

NASA Technical Reports Server (NTRS)

Ray-trace equations for uniaxial birefringent materials are used here to derive third-order estimates for aberrations that are produced in imaging through uniaxial plates and horizontal-vertical (HV) depolarizers. An HV depolarizer is a spatial pseudodepolarizer; it converts a uniform input polarization state into a continuum of spatially varying polarization states in an output beam. An HV depolarizer consists of two birefringent wedges whose crystal axes are crossed at 90 deg. The interface between the wedges is included, which leads to a spatially varying retardance that provides the spatial pseudodepolarization. In HV depolarizers, spherical aberration, astigmatism, and image doubling are the principal aberrations for on-axis objects. Only spherical aberration occurs in isotropic plates, while the presence of birefringent wedges introduces astigmatism and image doubling. It is shown that image separation is proportional to the magnitude of the retardance variation.

Mcclain, Stephen C.; Chipman, Russell A.; Hillman, Lloyd W.

1992-01-01

317

Natural convection on a vertical stretching cylinder  

NASA Astrophysics Data System (ADS)

The flow and natural (or mixed) convection due to a vertical stretching cylinder is studied. Using similarity transforms, the Navier-Stokes and energy equations reduce to a set of nonlinear ordinary differential equations. Asymptotic analysis for large Reynolds numbers shows the relation between axisymmetric flow and two-dimensional flow. Due to the algebraic decay of the similarity functions, numerical integration is performed using a compressed coordinate. The axial velocity is composed of forced convection due to stretching and natural convection from the heated cylinder. The heat transfer increases with both the Reynolds number and the Prandtl number. The result is also a rare similarity solution of the free convection and Navier-Stokes equations.

Wang, C. Y.

2012-03-01

318

Vertical axis wind turbine control strategy  

SciTech Connect

Early expensive in automatic operation of the Sandia 17-m vertical axis research wind turbine (VAWT) has demonstrated the need for a systematic study of control algorithms. To this end, a computer model has been developed that uses actual wind time series and turbine performance data to calculate the power produced by the Sandia 17-m VAWT operating in automatic control. The model has been used to investigate the influence of starting algorithms on annual energy production. The results indicate that, depending on turbine and local wind characteristics, a bad choice of a control algorithm can significantly reduce overall energy production. The model can be used to select control algorithms and threshold parameters that maximize long-term energy production. An attempt has been made to generalize these results from local site and turbine characteristics to obtain general guidelines for control algorithm design.

McNerney, G.M.

1981-08-01

319

Some aspects of fluctuating vertical wind shears  

SciTech Connect

Fluctuating vertical shears of wind speed have been measured using an array of towers. The statistical distributions of these shears are compared with formulas proposed by Fichtl (1971, 1972) and good agreement is found. A comparison of Fichtl's formula for the standard deviation of the fluctuating shears with a more empirical one proposed by Ramsdell (1978) shows that the latter is consistent with the former under the proper conditions. The probability of occurrence of extreme shears in speed is discussed. Directional shears are not treated. Fluctuating shears two or more times larger than the mean values are shown to be readily obtainable, and their likelihood increases as the mean measuring height increases if ..delta..Z is held fixed.

Doran, J.C.

1981-05-01

320

Integrated Vertical Bloch Line (VBL) memory  

NASA Technical Reports Server (NTRS)

Vertical Bloch Line (VBL) Memory is a recently conceived, integrated, solid state, block access, VLSI memory which offers the potential of 1 Gbit/sq cm areal storage density, data rates of hundreds of megabits/sec, and submillisecond average access time simultaneously at relatively low mass, volume, and power values when compared to alternative technologies. VBLs are micromagnetic structures within magnetic domain walls which can be manipulated using magnetic fields from integrated conductors. The presence or absence of BVL pairs are used to store binary information. At present, efforts are being directed at developing a single chip memory using 25 Mbit/sq cm technology in magnetic garnet material which integrates, at a single operating point, the writing, storage, reading, and amplification functions needed in a memory. The current design architecture, functional elements, and supercomputer simulation results are described which are used to assist the design process.

Katti, R. R.; Wu, J. C.; Stadler, H. L.

1991-01-01

321

Vertical structure of recent Arctic warming.  

PubMed

Near-surface warming in the Arctic has been almost twice as large as the global average over recent decades-a phenomenon that is known as the 'Arctic amplification'. The underlying causes of this temperature amplification remain uncertain. The reduction in snow and ice cover that has occurred over recent decades may have played a role. Climate model experiments indicate that when global temperature rises, Arctic snow and ice cover retreats, causing excessive polar warming. Reduction of the snow and ice cover causes albedo changes, and increased refreezing of sea ice during the cold season and decreases in sea-ice thickness both increase heat flux from the ocean to the atmosphere. Changes in oceanic and atmospheric circulation, as well as cloud cover, have also been proposed to cause Arctic temperature amplification. Here we examine the vertical structure of temperature change in the Arctic during the late twentieth century using reanalysis data. We find evidence for temperature amplification well above the surface. Snow and ice feedbacks cannot be the main cause of the warming aloft during the greater part of the year, because these feedbacks are expected to primarily affect temperatures in the lowermost part of the atmosphere, resulting in a pattern of warming that we only observe in spring. A significant proportion of the observed temperature amplification must therefore be explained by mechanisms that induce warming above the lowermost part of the atmosphere. We regress the Arctic temperature field on the atmospheric energy transport into the Arctic and find that, in the summer half-year, a significant proportion of the vertical structure of warming can be explained by changes in this variable. We conclude that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification. PMID:18172495

Graversen, Rune G; Mauritsen, Thorsten; Tjernström, Michael; Källén, Erland; Svensson, Gunilla

2008-01-01

322

Moving-base simulation evaluation of thrust margins for vertical landing for the NASA YAV-8B Harrier aircraft  

NASA Technical Reports Server (NTRS)

A simulation experiment was conducted on Ames Research Center's Vertical Motion Simulator to evaluate the thrust margin for vertical landing required for the YAV-8B Harrier. Two different levels of ground effect were employed, representing the aircraft with or without lift improvement devices installed. In addition, two different inlet temperature profiles were included to cover a wide range of hot gas ingestion. For each ground effect and hot gas ingestion variant, vertical landings were performed at successively heavier weights, with the pilot assessing the acceptability of the operation in each case. Results are presented as a function of hover weight ratio and a metric of the mean ground effect and ingestion that reflect the increase in thrust margin required to provide acceptable control of sink rate during the descent to touchdown with increasing suck down and hot gas ingestion.

Franklin, James A.; Stortz, Michael W.

1993-01-01

323

Numerical investigation of thermosolutal natural convection in a rectangular enclosure of an aspect ratio four with heat and solute sources  

NASA Astrophysics Data System (ADS)

A numerical study of double-diffusive natural convection in an enclosure with a partial vertical heat and mass sources for an aspect ratio Ar = 4 has been carried out. The influence of various dimensionless parameters (Rayleigh number, buoyancy ratio, source location, Lewis number, and source length) on the flow behavior are investigated. Correlations of average Nusselt and Sherwood numbers are obtained as function of two parameters (Ra, d) and (Le, d), respectively.

Oueslati, Fakher; Ben-Beya, Brahim; Lili, Taieb

2014-05-01

324

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

325

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

326

Modular low-aspect-ratio high-beta torsatron  

DOEpatents

A fusion-reactor device is described 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 planed 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 toroid defined by the modular coils preferably has a race track 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, G.V.

1982-04-01

327

Vertically resolved aerosol properties by multi wavelengths lidar measurements  

NASA Astrophysics Data System (ADS)

A new approach is introduced to characterize the dependence on altitude of the aerosol fine mode radius (Rf) and of the fine mode contribution (?) to the aerosol optical thickness (AOT) by three-wavelength lidar measurements. The introduced approach is based on the graphical method of Gobbi et al. (2007), which was applied to AERONET spectral extinction observations and relies on the combined analysis of the Ångstrom exponent (å) and its spectral curvature ?å. Lidar measurements at 355, 532 and 1064 nm were used in this study to retrieve the vertical profiles of å and ?å and to determine the dependence on altitude of Rf and ? (532 nm) from the å-?å combined analysis. Lidar measurements were performed at the Mathematics and Physics Department of Universita' del Salento, in south eastern Italy. Aerosol from continental Europe, the Atlantic, northern Africa, and the Mediterranean Sea are often advected over south eastern Italy and as a consequence, mixed advection patterns leading to aerosol properties varying with altitude are dominant. The proposed approach was applied to eleven measurement days to demonstrate its feasibility in different aerosol load conditions. The selected-days were characterized by AOTs spanning the 0.23-0.67, 0.15-0.41, and 0.04-0.25 range at 355, 532, and 1064 nm, respectively. Lidar ratios varied within the 28-80, 30-70, and 30-55 sr range at 355, 532, and 1064 nm, respectively, for the high variability of the aerosol optical and microphysical properties. å(355 nm, 1064 nm) values retrieved from lidar measurements ranged between 0.12 and 2.5 with mean value ±1 standard deviation equal to 1.4 ± 0.5. ?å varied within the -0.10-0.87 range with mean value equal to 0.1 ± 0.4. Rf and ? (532 nm) values spanning the 0.02-0.30 ?m and the 0.30-0.99 range, respectively were associated to the å-?å data points. Rf and ? values showed no dependence on the altitude. 72% of the data points were in the ?å-å space delimited by the ? and Rf curves varying within 0.70-0.95 and 0.15-0.05 ?m, respectively for the dominance of fine mode particles in driving the AOT over south eastern Italy. Volume depolarization vertical profiles retrieved from lidar measurements, aerosol products from AERONET sunphotometer measurements collocated in space and time, the BSC-DREAM model, analytical back trajectories, and satellite images were used to demonstrate the robustness of the proposed method.

Perrone, M. R.; De Tomasi, F.; Gobbi, G. P.

2013-07-01

328

Head-position-dependent Adaptation of Nonconcomitant Vertical Skew  

Microsoft Academic Search

Vertical phoria can be trained to vary with either head position or orbital eye position. The present experiments show that subjects can simultaneously adapt their eye-position-specific (nonconcomi- tant) vertical phorias in different directions at different head positions. Eye-position-dependent and head-position-dependent adaptive pathways, therefore, are not independent. Rather, the adaptation of vertical skew takes into account both eye and head position.

JAMES S. MAXWELL; CLIFTON M. SCHOR

329

Head-position-dependent Adaptation of Nonconcomitant Vertical Skew  

Microsoft Academic Search

Vertical phoria can be trained to vary with either head position or orbital eye position. The present experiments show that subjects can simultaneously adapt their eye-position-specific (nonconcomitant) vertical phorias in different directions at different head positions. Eye-position-dependent and head-position-dependent adaptive pathways, therefore, are not independent. Rather, the adaptation of vertical skew takes into account both eye and head position. In

JAMES S MAXWELL; CLIFTON M SCHOR

1997-01-01

330

Large-displacement vertical microlens scanner with low driving voltage  

Microsoft Academic Search

We have designed, fabricated, and demonstrated large vertical displacement vertical microlens scanners with low (<10 V) driving voltage using silicon-on-insulator technology. The unique isolated and pre-engaged vertical comb-drive sets and the coupled-torsion flexure design provide both upward and downward piston motions, as well as low driving voltages. Single-directional devices demonstrate maximum static downward displacement of 8 ?m at 10 Vdc.

Sunghoon Kwon; V. Milanovic; L. P. Lee

2002-01-01

331

Three-dimensional Numerical Analysis on Blade Response of Vertical Axis Tidal Current Turbine Under Operational Condition  

SciTech Connect

Tidal power as a large-scale renewable source of energy has been receiving significant attention recently because of its advantages over the wind and other renewal energy sources. The technology used to harvest energy from tidal current is called a tidal current turbine. Though some of the principles of wind turbine design are applicable to tidal current turbines, the design of latter ones need additional considerations like cavitation damage, corrosion etc. for the long-term reliability of such turbines. Depending up on the orientation of axis, tidal current turbines can be classified as vertical axis turbines or horizontal axis turbines. Existing studies on the vertical axis tidal current turbine focus more on the hydrodynamic aspects of the turbine rather than the structural aspects. This paper summarizes our recent efforts to study the integrated hydrodynamic and structural aspects of the vertical axis tidal current turbines. After reviewing existing methods in modeling tidal current turbines, we developed a hybrid approach that combines discrete vortex method -finite element method that can simulate the integrated hydrodynamic and structural response of a vertical axis turbine. This hybrid method was initially employed to analyze a typical three-blade vertical axis turbine. The power coefficient was used to evaluate the hydrodynamic performance, and critical deflection was considered to evaluate the structural reliability. A sensitivity analysis was also conducted with various turbine height-to-radius ratios. The results indicate that both the power output and failure probability increase with the turbine height, suggesting a necessity for optimal design. An attempt to optimize a 3-blade vertical axis turbine design with hybrid method yielded a ratio of turbine height to radius (H/R) about 3.0 for reliable maximum power output.

Li, Ye; Karri, Naveen K.; Wang, Qi

2014-04-30

332

Fabrication of submicron high-aspect-ratio GaAs actuators  

Microsoft Academic Search

Submicron, single-crystal gallium arsenide (SC-GaAs) actuators have been designed, fabricated, and operated. The fabrication process, called SCREAM-II (single crystal reactive etching and metallization II), uses chemically assisted ion beam etching (CAIBE) and reactive ion etching (RIE) to produce suspended and movable SC-GaAs structures with up to a 25:1 aspect ratio of vertical depth to lateral width (400 nm). Integrated actuators

Z. Lisa Zhang; Noel C. MacDonald

1993-01-01

333

Fabrication of submicron high-aspect-ratio GaAs actuators  

Microsoft Academic Search

Submicron, single-crystal gallium arsenide (SC-GaAs) actuators have been designed, fabricated, and operated. The fabrication process, called SCREAM-II (single crystal reactive etching and metallization II), uses chemically assisted ion beam etching (CAIBE) and reactive ion etching (RIE) to produce suspended and movable SC-GaAs structures with up to a 25:1 aspect ratio of vertical depth (10 ?m) to lateral width (400 nm).

Z. Lisa Zhang; Noel C. MacDonald

1993-01-01

334

Effect of Transient Seismic Noise on Estimates of H\\/V Spectral Ratios  

Microsoft Academic Search

The horizontal-to-vertical (H\\/V) spectral ratio of seismic noise has be- come a widely used tool in microzonation over the last decade. However, attempts to provide standards for seismic-noise analysis have only recently been made. One point often debated is whether only the stationary part of the recorded signal must be used or also the transients. Until now, no systematic analysis

S. Parolai; J. J. Galiana-Merino

2006-01-01

335

A comprehensive study of ion track enabled high aspect ratio microstructures in flexible circuit boards  

Microsoft Academic Search

A process to form deep, vertical and high aspect ratio microstructures of solid as well as porous nature is presented. The process is capable of producing regions with perpendicular sub-micron metal wire connections, with a regulated effective metal density at numerous, arbitrarily specified locations. The structures are created in a two-metallic-layer polyimide laminate, i.e. a flexible printed circuit board. The

M. Lindeberg; K. Hjort

2004-01-01

336

Self-assembled metallic nanowire-based vertical organic field-effect transistor.  

PubMed

We report on in situ, self-assembly, solution-processing of metallic (Au/Ag) nanowire-based transparent electrodes integrated to vertical organic field-effect transistors (VOFETs). In the VOFET architecture, the nanowires' microstructure facilitates current modulation by the gate across the otherwise shielding sandwiched source electrode. We show N-type VOFETs operation with on/off ratio ?1 × 10(5) and high current density (>1 mA cm(-2) at VDS = 5 V). The integration of the device design and the transparent electrode deposition methods offers a potential route for all-solution processing-based, large-area, high-efficiency organic electronics. PMID:25602371

Ben-Sasson, Ariel J; Azulai, Daniel; Gilon, Hagit; Facchetti, Antonio; Markovich, Gil; Tessler, Nir

2015-02-01

337

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

338

Vapor detection performance of vertically aligned, ordered arrays of silicon nanowires with a porous electrode.  

PubMed

Vertically aligned, ordered arrays of silicon nanowires capped with a porous top electrode are used to detect gas phase ammonia and nitrogen dioxide in humidified air. The sensors had very fast response times and large signal-to-noise ratios. Calibration curves were created using both an initial slope method and a fixed-time point method. The initial-slope method had a power law dependence that correlates well with concentration, demonstrating a viable alternative for eventual quantitative vapor detection and enabling shorter sampling and regeneration times. PMID:21563827

Field, Christopher R; In, Hyun Jin; Begue, Nathan J; Pehrsson, Pehr E

2011-06-15

339

Shape evolution of high aspect ratio holes on Si(001) during hydrogen annealing  

NASA Astrophysics Data System (ADS)

We study the dynamics of void formation through the shape evolution of high-aspect-ratio cylindrical holes in Si(001) substrates under hydrogen annealing. We compare the observed evolution of these holes with numerical simulations based on the continuum theory for surface-diffusion-driven shape evolution. We find that a strong morphological instability arises near the hole opening, regardless of the presence of anisotropy in surface energy. The observed shape evolution of high-aspect-ratio holes during hydrogen annealing is understood as a surface-diffusion-driven evolution subject to the stability of the facets which form the vertical sidewall.

Sudoh, K.; Hiruta, R.; Kuribayashi, H.

2013-11-01

340

Aerosol properties computed from aircraft-based observations during the ACE- Asia campaign. 2; A case study of lidar ratio closure and aerosol radiative effects  

NASA Technical Reports Server (NTRS)

For a vertical profile with three distinct layers (marine boundary, pollution and dust), observed during the ACE-Asia campaign, we carried out a comparison between the modeled lidar ratio vertical profile and that obtained from collocated airborne NASA AATS-14 sunphotometer and shipborne Micro-Pulse Lidar (MPL) measurements. Vertically resolved lidar ratio was calculated from two size distribution vertical profiles - one obtained by inversion of sunphotometer-derived extinction spectra, and one measured in-situ - combined with the same refractive index model based on aerosol chemical composition. The aerosol model implies single scattering albedos of 0.78 - 0.81 and 0.93 - 0.96 at 0.523 microns (the wavelength of the lidar measurements), in the pollution and dust layers, respectively. The lidar ratios calculated from the two size distribution profiles have close values in the dust layer; they are however, significantly lower than the lidar ratios derived from combined lidar and sunphotometer measurements, most probably due to the use of a simple nonspherical model with a single particle shape in our calculations. In the pollution layer, the two size distribution profiles yield generally different lidar ratios. The retrieved size distributions yield a lidar ratio which is in better agreement with that derived from lidar/sunphotometer measurements in this layer, with still large differences at certain altitudes (the largest relative difference was 46%). We explain these differences by non-uniqueness of the result of the size distribution retrieval and lack of information on vertical variability of particle refractive index. Radiative transfer calculations for this profile showed significant atmospheric radiative forcing, which occurred mainly in the pollution layer. We demonstrate that if the extinction profile is known then information on the vertical structure of absorption and asymmetry parameter is not significant for estimating forcing at TOA and the surface, while it is of importance for estimating vertical profiles of radiative forcing and heating rates.

Kuzmanoski, Maja; Box, M. A.; Schmid, B.; Box, G. P.; Wang, J.; Russell, P. B.; Bates, D.; Jonsson, H. H.; Welton, Ellsworth J.; Flagan, R. C.

2005-01-01

341

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

342

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

343

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

344

Vertically Integrated Rheology of Deforming Oceanic Lithosphere  

NASA Astrophysics Data System (ADS)

The tectonics of the oceans have traditionally been modeled in terms of rigid plates interacting at narrow boundaries. The now well-documented existence of diffuse oceanic plate boundaries, across which relative motion is distributed over hundreds to thousands of kilometers, demonstrates the need for a different approach to understanding the tectonics and geodynamics of a substantial fraction of oceanic lithosphere. A model that has usefully been applied to diffuse zones of continental deformation is that of a thin viscous sheet of fluid obeying a power-law rheology. The model has few adjustable parameters, typically a power-law exponent, n, and the Argand number [England & McKenzie, 1982], which is a measure of the size of buoyancy forces caused by the deformation, and which can be neglected for deformation of oceanic lithosphere. In prior investigations of a thin sheet of power-law fluid for continental regions, most studies have found that the most appropriate power-law exponent is ?3 [e.g., England & Molnar 1991, 1997], but a value as large as ?10 has been recently suggested by Dayem et al. [2009]. Because the rheology of oceanic lithosphere differs significantly from that of continental lithosphere, the most appropriate exponent may be larger than 3, and should in some sense be an appropriately weighted average between the properties of the upper lithosphere, which deforms brittlely and semi-brittlely, and for which the power-law exponent is n ? ?, and the lower lithosphere, which deforms by dislocation glide [Goetze 1978; Evans & Goetze 1979; Ratteron et al. 2003; Dayem et al. 2009; Mei et al. 2010], which obeys an exponential law, and by dislocation creep for which n?3 [Sonder & England, 1986]. To estimate the appropriate power-law exponent consistent with laboratory experiments we determine strain rate as a function of applied end load on the lithosphere for various ages of lithosphere. We find that a power-law fluid well approximates the vertically integrated rheology of oceanic lithosphere determined from laboratory experiments and that the best-fitting power-law exponent for the vertically integrated rheology is insensitive to strain rate. We also find that, except for very young lithosphere (< ?10 Ma old), the best-fitting power law exponent is insensitive to the age of the lithosphere, with the value of the exponent being between 14 and 16 when failing for thrust faulting for the flow laws of Kohlstedt et al [1995] and between 15 and 19 for more recently published flow laws. These results support the application of thin viscous sheet models to diffuse oceanic plate boundaries, such as the ones accommodating motion between the India, Capricorn, and Australia plates in the Indian Ocean.

Mishra, J. K.; Gordon, R. G.

2011-12-01

345

On the Vertical Structuring of Gigantic Jets  

NASA Astrophysics Data System (ADS)

Gigantic Jets (GJs) are large-scale electrical discharges between the thundercloud tops and the lower ionosphere. It is estimated that an individual GJ can contribute as much as cloud-to-ground lightning in discharging a thunderstorm system, transferring hundreds of coulombs from thundercloud to the ionosphere [Cummer et al., Nat. Geosci., 2, 617-620, 2009]. GJs are initiated deep inside the thundercloud as intracloud lightning discharges. Owing to a charge imbalance, meaning the upper charge center is depleted with respect to the midlevel charge center, the upward-directed lightning leaders manage to escape through the thundercloud top to form GJs [Krehbiel et al., Nat. Geosci., 1, 233-237, 2008]. As a GJ leader crosses the stratosphere its streamer zone becomes longer and longer, due to the dynamics of streamer growth in a medium with exponentially-decreasing air density, such as in the Earth's atmosphere [Raizer et al., GRL, 33, L23801, 2006]. The speed at which a leader propagates 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 [da Silva and Pasko, GRL, 39, L13805, 2012]. Despite the expected deceleration of an upward-directed leader, GJs are observed to accelerate as they approach the ionosphere. To address this issue, we propose a simple time-dynamic model for GJ propagation that simulates the upward propagation of a leader discharge accounting for the effects of the expansion of its streamer zone. 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 [da Silva and Pasko, GRL, 40, 12, 3315-3319, 2013]. Leaders and streamers are very different electrical discharges in terms of the degree of ionization, temperature, and composition of the plasma inside their channels. A correct description of the vertical structuring of GJs is of fundamental importance for evaluation of their effects in the stratosphere and mesosphere.

Da Silva, C.; Pasko, V. P.

2013-12-01

346

Development of Vertical Cable Seismic System  

NASA Astrophysics Data System (ADS)

In 2009, Ministry of Education, Culture, Sports, Science and Technology(MEXT) started the survey system development for Hydrothermal deposit. We proposed the Vertical Cable Seismic (VCS), the reflection seismic survey with vertical cable above seabottom. VCS has the following advantages for hydrothermal deposit survey. (1) VCS is an efficient high-resolution 3D seismic survey in limited area. (2) It achieves high-resolution image because the sensors are closely located to the target. (3) It avoids the coupling problems between sensor and seabottom that cause serious damage of seismic data quality. (4) Because of autonomous recording system on sea floor, various types of marine source are applicable with VCS such as sea-surface source (GI gun etc.) , deep-towed or ocean bottom source. Our first experiment of 2D/3D VCS surveys has been carried out in Lake Biwa, JAPAN, in November 2009. The 2D VCS data processing follows the walk-away VSP, including wave field separation and depth migration. Seismic Interferometry technique is also applied. The results give much clearer image than the conventional surface seismic. Prestack depth migration is applied to 3D data to obtain good quality 3D depth volume. Seismic Interferometry technique is applied to obtain the high resolution image in the very shallow zone. Based on the feasibility study, we have developed the autonomous recording VCS system and carried out the trial experiment in actual ocean at the water depth of about 400m to establish the procedures of deployment/recovery and to examine the VC position or fluctuation at seabottom. The result shows that the VC position is estimated with sufficient accuracy and very little fluctuation is observed. Institute of Industrial Science, the University of Tokyo took the research cruise NT11-02 on JAMSTEC R/V Natsushima in February, 2011. In the cruise NT11-02, JGI carried out the second VCS survey using the autonomous VCS recording system with the deep towed source provided by Institute of Industrial Science, the University of Tokyo. It generates high frequency acoustic waves around 1kHz. The acquired VCS data clearly shows the reflections and currently being processed for imaging the subsurface structure.

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

2011-12-01

347

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

348

Vertical Banded Gastroplasty vs Adjustable Silicone Gastric Banding in the Treatment of Morbid Obesity: a Preliminary Report  

Microsoft Academic Search

A prospective comparative study, comparing vertical banded gastroplasty (VBG) with adjustable silicone gastric banding (ASGB)\\u000a has been undertaken. The purpose of the study was to see if ASGB could produce weight loss as good as VBG. Patient population\\u000a was similar and patients' choice was based on informed consent. Male\\/female ratio and excess body weight were comparable in\\u000a both groups. Early

M. Belachew; P. Jacquet; F. Lardinois; C. Karler

1993-01-01

349

Natural convection heat transfer from a long heated vertical cylinder to an adjacent air gap of concentric and eccentric conditions  

Microsoft Academic Search

In this work, the natural convection heat transfer from a long vertical electrically heated cylinder to an adjacent air gap\\u000a is experimentally studied. The aspect and diameter ratios of the cylinder are 55.56 and 6.33, respectively. The experimental\\u000a measurements were obtained for a concentric condition and six eccentricities from 0.1 to 0.92 at five different heat fluxes.\\u000a The surface temperature

R. Hosseini; A. Rezania; M. Alipour; L. A. Rosendahl

2011-01-01

350

Vertically resolved aerosol properties by multi-wavelength lidar measurements  

NASA Astrophysics Data System (ADS)

An approach based on the graphical method of Gobbi and co-authors (2007) is introduced to estimate the dependence on altitude of the aerosol fine mode radius (Rf) and of the fine mode contribution (?) to the aerosol optical thickness (AOT) from three-wavelength lidar measurements. The graphical method of Gobbi and co-authors (2007) was applied to AERONET (AErosol RObotic NETwork) spectral extinction observations and relies on the combined analysis of the Ångstrom exponent (å) and its spectral curvature ?å. Lidar measurements at 355, 532 and 1064 nm were used in this study to retrieve the vertical profiles of å and ?å and to estimate the dependence on altitude of Rf and ?(532 nm) from the å-?å combined analysis. Lidar measurements were performed at the Department of Mathematics and Physics of the Universita' del Salento, in south-eastern Italy. Aerosol from continental Europe, the Atlantic, northern Africa, and the Mediterranean Sea are often advected over south-eastern Italy and as a consequence, mixed advection patterns leading to aerosol properties varying with altitude are dominant. The proposed approach was applied to ten measurement days to demonstrate its feasibility in different aerosol load conditions. The selected days were characterized by AOTs spanning the 0.26-0.67, 0.15-0.39, and 0.04-0.27 range at 355, 532, and 1064 nm, respectively. Mean lidar ratios varied within the 31-83, 32-84, and 11-47 sr range at 355, 532, and 1064 nm, respectively, for the high variability of the aerosol optical and microphysical properties. å values calculated from lidar extinction profiles at 355 and 1064 nm ranged between 0.1 and 2.5 with a mean value ± 1 standard deviation equal to 1.3 ± 0.7. ?å varied within the -0.1-1 range with mean value equal to 0.25 ± 0.43. Rf and ?(532 nm) values spanning the 0.05-0.3 ?m and the 0.3-0.99 range, respectively, were associated with the å-?å data points. Rf and ? values showed no dependence on the altitude. 60% of the data points were in the ?å-å space delimited by the ? and Rf curves varying within 0.80-0.99 and 0.05-0.15 ?m, respectively, for the dominance of fine-mode particles in driving the AOT over south-eastern Italy. Vertical profiles of the linear particle depolarization ratio retrieved from lidar measurements, aerosol products from AERONET sun photometer measurements collocated in space and time, analytical back trajectories, satellite true colour images, and dust concentrations from the BSC-DREAM (Barcelona Super Computing Center-Dust REgional Atmospheric Model) model were used to demonstrate the robustness of the proposed method.

Perrone, M. R.; De Tomasi, F.; Gobbi, G. P.

2014-02-01

351

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

352

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

353

ATLAS LTCS Vertically Challenged System Lessons Learned  

NASA Technical Reports Server (NTRS)

Re-planning of LTCS TVAC testing and supporting RTA (Receiver Telescope Assembly) Test Plan and Procedure document preparation. The Laser Thermal Control System (LTCS) is designed to maintain the lasers onboard Advanced Topographic Laser Altimeter System (ATLAS) at their operational temperatures. In order to verify the functionality of the LTCS, a thermal balance test of the thermal hardware was performed. During the first cold start of the LTCS, the Loop Heat Pipe (LHP) was unable to control the laser mass simulators temperature. The control heaters were fully on and the loop temperature remained well below the desired setpoint. Thermal analysis of the loop did not show these results. This unpredicted behavior of the LTCS was brought up to a panel of LHP experts. Based on the testing and a review of all the data, there were multiple diagnostic performed in order to narrow down the cause. The prevailing theory is that gravity is causing oscillating flow within the loop, which artificially increased the control power needs. This resulted in a replan of the LTCS test flow and the addition of a GSE heater to allow vertical operation.

Patel, Deepak; Garrison, Matt; Ku, Jentung

2014-01-01

354

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

355

Aberrations of a horizontal-vertical depolarizer.  

PubMed

We use ray-trace equations for uniaxial birefringent materials to derive third-order estimates for aberrations that are produced in imaging through uniaxial plates and horizontal-vertical (HV) depolarizers. An HV depolarizer is a spatial pseudodepolarizer; it converts a uniform input polarization state into a continuum of spatially varying polarization states in an output beam. An HV depolarizer consists of two birefringent wedges whose crystal axes are crossed at 90 degrees . The interface between the wedges is inclined, which leads to a spatially varying retardance that provides the spatial pseudodepolarization. In HV depolarizers, spherical aberration, astigmatism, and image doubling are the principal aberrations for on-axis objects. Only spherical aberration occurs in isotropic plates, while the presence of birefringent wedges introduces astigmatism and image doubling. It is shown that image separation is proportional tothe magnitude of the retardance variation. Image separation is independent of the thickness, wedge angle, and refractive indices that are used to achieve this variation. A computer program is used to perform an exact birefringent ray trace and produces spot diagrams that confirm the aberration estimates. PMID:20720897

McClain, S C; Chipman, R A; Hillman, L W

1992-05-01

356

Current Apertured Vertical Electron Transistor (CAVET)  

NASA Astrophysics Data System (ADS)

We have demonstrated the first GaN current aperture vertical electron transistor (CAVET). A 2 micrometer thick GaN:Si drain region followed by a 0.4 micrometer GaN:Fe insulating layer and an 800 Angstrom unintentionally doped GaN cap were grown by MOCVD on a c-plane sapphire substrate. Channel apertures were etched, and a maskless regrowth was performed to grow conducting GaN inside the channel as well as to thicken the UID GaN above the insulating layer and add an AlGaN cap layer. C12 RIE was used to pattern the device mesa. Source, drain, and gate pads were then deposited. Devices with aperture widths ranging from 0.4 micrometer to 2 micrometer have been demonstrated. DC transistor characteristics were measured, and the effects of varying the aperture length and the gate overlap were investigated. Electrical characteristics of a device with a 0.6 micrometer aperture and a gate overlap of 2 micrometer are illustrated in Fig 2. This device had a source-drain saturation current of 430 mA/mm and an extrinsic transconductance of 100 mS/mm. Additionally, conditions for PEC etching of an InGaN layer for the CAVET illustrated in Fig 1d have been optimized.

Mishra, Umesh K.

2001-12-01

357

Engineering design of vertical test stand cryostat  

SciTech Connect

Under Indian Institutions and Fermilab collaboration, Raja Ramanna Centre for Advanced Technology and Fermi National Accelerator Laboratory are jointly developing 2K Vertical Test Stand (VTS) cryostats for testing SCRF cavities at 2K. The VTS cryostat has been designed for a large testing aperture of 86.36 cm for testing of 325 MHz Spoke resonators, 650 MHz and 1.3 GHz multi-cell SCRF cavities for Fermilab's Project-X. Units will be installed at Fermilab and RRCAT and used to test cavities for Project-X. A VTS cryostat comprises of liquid helium (LHe) vessel with internal magnetic shield, top insert plate equipped with cavity support stand and radiation shield, liquid nitrogen (LN{sub 2}) shield and vacuum vessel with external magnetic shield. The engineering design and analysis of VTS cryostat has been carried out using ASME B&PV Code and Finite Element Analysis. Design of internal and external magnetic shields was performed to limit the magnetic field inside LHe vessel at the cavity surface <1 {micro}T. Thermal analysis for LN{sub 2} shield has been performed to check the effectiveness of LN{sub 2} cooling and for compliance with ASME piping code allowable stresses.

Suhane, S.K.; Sharma, N.K.; Raghavendra, S.; Joshi, S.C.; Das, S.; Kush, P.K.; Sahni, V.C.; Gupta, P.D.; /Indore, Ctr. for Advanced Tech.; Sylvester, C.; Rabehl, R.; Ozelis, J.; /Fermilab

2011-03-01

358

Mudflow rheology in a vertically rotating flume  

USGS Publications Warehouse

Joint research by the U.S. Geological Survey and the University of Missouri-Rolla currently (1990) is being conducted on a 3.05 meters in diameter vertically rotating flume used to simulate mudflows under steady-state conditions. Observed mudflow simulations indicate flow patterns in the flume are similar to those occurring in natural mudflows. Variables such as mean and surface velocity, depth, and average boundary shear stress can be measured in this flume more easily than in the field or in a traditional tilting flume. Sensitive variables such as sediment concentration, grain-size distribution, and Atterberg limits also can be precisely and easily controlled. A known Newtonian fluid, SAE 30 motor oil, was tested in the flume and the computed value for viscosity was within 12.5 percent of the stated viscosity. This provided support that the data from the flume can be used to determine the rheological properties of fluids such as mud. Measurements on mud slurries indicate that flows with sediment concentrations ranging from 81 to 87 percent sediment by weight can be approximated as Bingham plastic for strain rates greater than 1 per second. In this approximation, the yield stress and Bingham viscosity were extremely sensitive to sediment concentration. Generally, the magnitude of the yield stress was large relative to the change in shear stress with increasing mudflow velocity.

Holmes, Robert R.; Westphal, Jerome A.; Jobson, Harvey E.

1990-01-01

359

Absolute Position Encoders With Vertical Image Binning  

NASA Technical Reports Server (NTRS)

Improved optoelectronic patternrecognition encoders that measure rotary and linear 1-dimensional positions at conversion rates (numbers of readings per unit time) exceeding 20 kHz have been invented. Heretofore, optoelectronic pattern-recognition absoluteposition encoders have been limited to conversion rates <15 Hz -- too low for emerging industrial applications in which conversion rates ranging from 1 kHz to as much as 100 kHz are required. The high conversion rates of the improved encoders are made possible, in part, by use of vertically compressible or binnable (as described below) scale patterns in combination with modified readout sequences of the image sensors [charge-coupled devices (CCDs)] used to read the scale patterns. The modified readout sequences and the processing of the images thus read out are amenable to implementation by use of modern, high-speed, ultra-compact microprocessors and digital signal processors or field-programmable gate arrays. This combination of improvements makes it possible to greatly increase conversion rates through substantial reductions in all three components of conversion time: exposure time, image-readout time, and image-processing time.

Leviton, Douglas B.

2005-01-01

360

A Multifunctional Smart, Flexible, Vertical, Cantilevered Beam  

NSDL National Science Digital Library

This paper presents the development and application of a smart, flexible, vertical cantilevered beam system for experimentation and demonstration of vibration system modeling as a reinforcement to undergraduate dynamics education. Focusing on the difficult concepts of transfer functions and frequency domain based analysis, the beam system aids students in grasping basic vibration system concepts by allowing them to analyze and manipulate real system data collected through a simple and inexpensive piezoceramic-based data acquisition and actuation system. Students observed and analyzed the dynamic responses of a flexible aluminum beam subjected to various input signals to draw conclusions and relationships between system input and system response through the use of Bode diagrams, relationships often difficult for students to appreciate without experimental experiences. Results from post-demonstration student surveys indicate that the students found the demonstrations of the flexible beam system to be exceptionally effective in improving and motivating learning in their courses, with 94% of student responses rating the beam system as effective or very effective in various aspects of the demonstration.

Bannerot, Richard; Chang, Christy; Singla, Mithun; Song, Gangbing

2011-05-12

361

Vertical array measurements of humpback whale songs  

NASA Astrophysics Data System (ADS)

The songs of eight male humpback whales were recorded at ranges varying from 20 to 40 m with a vertical array of hydrophones that had a flat frequency response to 24 kHz. The songs consisted of bursts of sounds called units. Units were organized into phrases and phrases into themes. Most of the units had mean duration between 1 and 2 s and mean silent periods between units between 1 and 2 s. Many of the recorded songs contained units that had high-frequency harmonics that extended beyond 22 kHz. These harmonic results suggest that humpback whale songs have a broadband quality not previously reported and may provide some insights on the high-frequency limit of hearing in these whales. The source levels of the songs were also estimated by considering the root-mean-square sound-pressure level referenced to 1 m for the unit with the largest level for different phrase within a song. Source levels varied between 171 to 189 dB re: 1 ?Pa. Singing escorts have been regularly observed within two whale lengths of females and these observations and knowledge of source levels provide estimates of sound-pressure levels that male humpback whales expose female whales to.

Au, Whitlow W. L.; Lammers, Marc O.; Pack, Adam A.; Herman, Louis

2001-05-01

362

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

363

Anorthite Weathering: Rates from Vertical Scanning Interferometry  

NASA Astrophysics Data System (ADS)

Feldspar weathering plays an important role in many environmental and engineering problems, including waste disposal, groundwater movement, and diagenesis. As the most abundant rock forming minerals in the Earth's crust, feldspar dissolution rates are especially important parameters in global flux models, as well as in smaller scale kinetic dissolution models. We present results based on the dissolution rates of anorthite measured during single-crystal, flow-through experiments at varying temperature and saturation state. The experiments are conducted in a 0.01M solution of sodium tetraborate with pH 9. Saturation states with respect to anorthite are controlled by adding known concentrations of aluminum chloride, calcium chloride, and sodium meta-silicate. Using vertical scanning interferometry we obtain absolute measurements of the rate of the mineral's surface normal retreat. From the molar volume of the mineral and the velocity of the surface normal retreat we calculate absolute rate constants. No external measurement of surface area is necessary. Each measurement by the interferometer produces up to 600,000 individual rate data. Statistical analyses of these data account for the heterogeneity of dissolution across the mineral surface and can provide an average dissolution rate constant that can be compared to bulk rates obtained from powder or weight loss experiments and with rates measured by AFM. Comparing data from various techniques is important for identifying the relationship between the varying rates obtained by the different methods, as well as to rates measured in the field.

Beig, M. S.; Luttge, A.

2001-12-01

364

TRIGONOMETRY: COMPARING RATIO AND UNIT CIRCLE METHODS  

Microsoft Academic Search

Before the 1960s, introductory trigonometry was taught in Victorian schools using the ratio method, where trigonometric functions are defined as ratios of sides of right angled triangles. With the advent of \\

Margaret Kendal; Kaye Stacey

365

Variable mixture ratio performance through nitrogen augmentation  

NASA Technical Reports Server (NTRS)

High/variable mixture ratio O2/H2 candidate engine cycles are examined for earth-to-orbit vehicle application. Engine performance and power balance information are presented for the candidate cycles relative to chamber pressure, bulk density, and mixture ratio. Included in the cycle screening are concepts where a third fluid (liquid nitrogen) is used to achieve a variable mixture ratio over the trajectory from liftoff to earth orbit. The third fluid cycles offer a very low risk, fully reusable, low operation cost alternative to high/variable mixture ratio bipropellant cycles. Variable mixture ratio engines with extendible nozzle are slightly lower performing than a single mixture ratio engine (MR = 7:1) with extendible nozzle. Dual expander engines (MR = 7:1) have slightly better performance than the single mixture ratio engine. Dual fuel dual expander engines offer a 16 percent improvement over the single mixture ratio engine.

Beichel, R.; Obrien, C. J.; Bair, E. K.

1988-01-01

366

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.

367

Three-Dimensional Polymer Constructs Exhibiting a Tunable Negative Poisson’s Ratio  

PubMed Central

Young’s modulus and Poisson’s ratio of a porous polymeric construct (scaffold) quantitatively describe how it supports and transmits external stresses to its surroundings. While Young’s modulus is always non-negative and highly tunable in magnitude, Poisson’s ratio can, indeed, take on negative values despite the fact that it is non-negative for virtually every naturally occurring and artificial material. In some applications, a construct having a tunable negative Poisson’s ratio (an auxetic construct) may be more suitable for supporting the external forces imposed upon it by its environment. Here, three-dimensional polyethylene glycol scaffolds with tunable negative Poisson’s ratios are fabricated. Digital micromirror device projection printing (DMD-PP) is used to print single-layer constructs composed of cellular structures (pores) with special geometries, arrangements, and deformation mechanisms. The presence of the unit-cellular structures tunes the magnitude and polarity (positive or negative) of Poisson’s ratio. Multilayer constructs are fabricated with DMD-PP by stacking the single-layer constructs with alternating layers of vertical connecting posts. The Poisson’s ratios of the single- and multilayer constructs are determined from strain experiments, which show (1) that the Poisson’s ratios of the constructs are accurately predicted by analytical deformation models and (2) that no slipping occurrs between layers in the multilayer constructs and the addition of new layers does not affect Poisson’s ratio. PMID:21841943

Fozdar, David Y.; Soman, Pranav; Lee, Jin Woo; Han, Li-Hsin; Chen, Shaochen

2011-01-01

368

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

369

Heat-transfer characteristics of climbing film evaporation in a vertical tube  

SciTech Connect

Heat-transfer characteristics of climbing film evaporation were experimentally investigated on a vertical climbing film evaporator heated by tube-outside hot water. The experimental setup was designed for determining the effect of the height of feed water inside a vertical tube and the range of temperature difference on local heat transfer coefficient inside a vertical tube (h{sub i}). In this setup, the height of feed water was successfully controlled and the polypropylene shell effectively impedes the heat loss to the ground. The results indicated that a reduction in the height of feed water contributed to a significant increase in h{sub i} if no dry patches around the wall of the heated tube appeared inside the tube. The height ratio of feed water R{sub h} = 0.3 was proposed as the optimal one as dry patches destroyed the continuous climbing film when R{sub h} is under 0.3. It was found that the minimum temperature difference driving climbing film evaporation is suggested as 5 C due to a sharp reduction in h{sub i} for temperature difference below 5 C. The experiment also showed that h{sub i} increased with an increase in temperature difference, which proved the superiority of climbing film evaporation in utilizing low-grade surplus heating source due to its wide range of driving temperature difference. The experimental results were compared with the previous literature and demonstrated a satisfactory agreement. (author)

Yang, Luopeng; Chen, Xue; Shen, Shengqiang [Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, School of Energy and Power Engineering, Dalian University of Technology, Dalian 116024 (China)

2010-09-15

370

Computation of Cold-Start Miss Ratios  

Microsoft Academic Search

Cold-start miss ratios are miss ratios that are measured with an initially empty first-level store. The values obtained depend on C, the first-level storage capacity, and on T, the number of references. These miss ratios, measured for various values of T, are useful in evaluating the effect of task switching on cache miss ratios when the cache capacity is C.

Malcolm C. Easton

1978-01-01

371

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

372

Proposed technique for vertical alignment of a crane's cable  

NASA Technical Reports Server (NTRS)

Proposed vertical alignment technique senses the attitude of a cranes cable and displays any deviation from the vertical. The system consists of a detector assembly fixed to the boom and a display scope located in the cabin. It has potential application with either fixed-boom cranes or gantries.

Gera, J., Jr.

1969-01-01

373

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...

374

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´evennes, Vallon de Fontanes, 30520 St-Martin de Valgalgues, FRANCE Abstract This paper deals with the design of an H-observer to estimate the state variables of the vertical car dynamics to be used for suspension

Paris-Sud XI, Université de

375

Seismic passive resistance with vertical seepage and surcharge  

Microsoft Academic Search

Present paper focuses on the computation of the seismic passive earth pressure acting on a vertical rigid retaining wall by a soil mass subjected to vertical steady-state seepage and a uniform surcharge load. Based on the basic assumptions of Coulomb's theory and a pseudo-static method of analysis, a general solution for the passive earth pressure containing two coefficients is presented.

Jun-Jie Wang; Hui-Ping Zhang; He-Jun Chai; Jun-Gao Zhu

2008-01-01

376

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

377

Vertical flow in heavily exploited hard rock and alluvial aquifers  

Microsoft Academic Search

This paper examines the flow in heavily exploited alluvial and hard rock aquifers and demonstrates that vertical components of flow are of great importance. In a typical example of an alluvial aquifer it is shown that most of the discharge from tube wells originates from the phreatic surface flowing vertically through clay layers to the well screens. A second study

K. R. Rushton

1986-01-01

378

On the Dynamics of a Vertically Driven Damped Planar Pendulum  

E-print Network

On the Dynamics of a Vertically Driven Damped Planar Pendulum M. V. Bartuccelli # , G. Gentile Abstract The dynamics of the planar pendulum with parametric vertical time­periodic forcing is con­ sidered calculate the Lyapunov exponents to show that for some parameter values the dynamics of the pendulum shows

379

On the Dynamics of a Vertically Driven Damped Planar Pendulum  

E-print Network

On the Dynamics of a Vertically Driven Damped Planar Pendulum M. V. Bartuccelli # , G. Gentile on the dynamics of the planar pendulum with parametric vertical time­periodic forcing are reviewed and extended the dynamics of the pendulum shows sensitivity to initial conditions. Keywords: basins of attraction

Roma "La Sapienza", Università di

380

On the Dynamics of a Vertically Driven Damped Planar Pendulum  

E-print Network

On the Dynamics of a Vertically Driven Damped Planar Pendulum M. V. Bartuccelli #3; , G. Gentile y Results on the dynamics of the planar pendulum with parametric vertical time-periodic forcing are reviewed parameter values the dynamics of the pendulum shows sensitivity to initial conditions. Keywords: basins

Bartuccelli, Michele

381

The Subjective Visual Vertical: Validation of a Simple Test  

ERIC Educational Resources Information Center

The study sought to provide norms for a simple test of visual perception of verticality (subjective visual vertical). The study was designed as a cohort study with a balanced design. The setting was the Rehabilitation Department of a University Hospital. Twenty-two healthy adults, of 23-58 years, 11 men (three left handed) and 11 women (three left…

Tesio, Luigi; Longo, Stefano; Rota, Viviana

2011-01-01

382

Vertical transport of surface fire emissions observed Siegfried Gonzi1  

E-print Network

estimation to infer the vertical distribution of surface emissions lofted from boreal and tropical biomass of information. We use a maximum a posteriori (MAP) methodology to estimate emitted CO mass in five vertical, of which 672 are colocated with MLS. We define an injection height based on MAP statistics. We find that 10

Palmer, Paul

383

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

384

Amplitude distributions of vertically reflected radio waves at Waltair  

Microsoft Academic Search

Amplitude probability distributions of vertically reflected radio pulses from different regions of the ionosphere are presented. The nature of the reflecting surface is found to vary even during short intervals of time. M-type distributions are observed when there is an apparent vertical motion and also during the passage of a traveling ionospheric disturbance. Possible interpretations are given for the observed

B. S. N. Murthy; B. R. Rao

1973-01-01

385

Understanding Functions without Using the Vertical Line Test  

ERIC Educational Resources Information Center

Study was conducted on how the students were made to think meaningfully and widely within and across the representations in solving and identifying functions in precalculus, without the usage of the vertical line test. It was concluded that the "no vertical line testing" method proved to be easily accessible by all students and also made them…

Fernandez, Eileen

2005-01-01

386

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

387

Experimental and theoretical studies of vertical annular liquid jets  

Microsoft Academic Search

Theoretical studies are described of vertical annular jets, the conditions are determined under which vertical jets form an enclosed volume which can be used as a chemical reactor, the influence is assessed of the nozzle gap width, nozzle geometry, pressure difference across the annular jet, and Froude, Weber and Reynolds numbers on the annular jet's covergence length, and the mass

J. I. Ramos

1990-01-01

388

Productivity increase of the vertical roller mill for cement grinding  

Microsoft Academic Search

The specific power consumption, product quality and other performance of the “OK” and “CK” vertical roller mills for cement grinding are briefly stated. Hence, the enhancement in increasing the productivity of the vertical roller mill at Chichibu Onoda Cement Corporation (COCC) is introduced. These include: (a) restoring a table liner and roller tires by hard-facing to reduce maintenance costs; (b)

M. Ito; K. Sato; Y. Naoi

1997-01-01

389

Finish grinding with vertical roller mills-operating data  

Microsoft Academic Search

Vertical roller mills offer significant potential for savings when used for finish grinding. Two installations in Peru and the Dominican Republic are being examined with specific data on cement production, product fineness, specific power consumption and concrete strength. The vertical mill at Cementos Pacasmayo, SA in Peru was commissioned in December 1999, and the mill at Cementos Nacionales in Dominican

C. Oesch; B. Jurko

2002-01-01

390

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

391

SEEDCHASER: TILLAGE MODEL FOR VERTICAL WEED SEED DISTRIBUTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Knowledge of the vertical distribution of surface residues, chemicals, or seeds following tillage operations is of paramount importance to a wide variety of soil research areas. This paper describes a 1-D empirical vertical soil tillage particle distribution model with 1-cm grid spacing. Prior model...

392

Vertical optical floating zone furnace: Principles of irradiation profile formation  

Microsoft Academic Search

The light distribution within the vertical double-ellipsoid mirror furnace applied for floating zone crystal growth with optical heating is studied. During the last few years, this setup was intensively applied for crystal growth of intermetallic and oxide materials due to its advantages for radiation focussing, which is superior in some key features compared to other commercial horizontal and vertical optical

D. Souptel; W. Löser; G. Behr

2007-01-01

393

Vertical Distribution of Bacterivorous Nematodes under Different Wenju Liang,1  

E-print Network

Vertical Distribution of Bacterivorous Nematodes under Different Land Uses Wenju Liang,1 Xiaoke Zhang,1,3 Qi Li,1,3 Yong Jiang,1 Wei Ou,1,3 and Deborah A. Neher2 Abstract: The vertical distribution. In contrast, Chiloplacus and Prismatolaimus spp. were distributed down to 100-cm depth in the AC and CM

Neher, Deborah A.

394

PICTURE OF THE MONTH Vertically Pointing Airborne Doppler Radar Observations  

E-print Network

leg shown in Fig. 2. This value can be considered to be the average terminal velocity and zenith reflectivity and Doppler velocity, corrected for aircraft motion, are shown in a vertical cross are labeled in Figs. 1 and 2. The vertical velocity of the echoes tends to be nega- tive (downward) because

Geerts, Bart

395

19. VIEW SOUTHWEST OF INTERMEDIATE VERTICAL PENNSYLVANIA PETIT TRUSS WITH ...  

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

19. VIEW SOUTHWEST OF INTERMEDIATE VERTICAL PENNSYLVANIA PETIT TRUSS WITH CASTLE ROCK IN BACKGROUND. JUNCTION OF INTERMEDIATE VERTICAL AND TOP CHORD WITH STABILIZING LATERAL STRUT ABOVE AND SWAY STRUT BELOW. ORIGINAL PAIRED DIAGONAL EYE BARS LATER REINFORCED WITH TIE ROD - New River Bridge, Spanning New River at State Route 623, Pembroke, Giles County, VA

396

Vertical axis wind turbine designed aerodynamically at Tokai University  

Microsoft Academic Search

The advantages of the vertical axis wind turbine over conventional propeller-type wind turbines are listed, among them the fact that the turbine is free from the gyroscopic loading accompanied by wind direction tracking. Special attention is given to the straight-wing type vertical axis turbine, which is thought to be particularly advantageous. Also discussed are the characteristics of the blade. It

Y. Kato; K. Seki; Y. Shimizu

1981-01-01

397

OPC UA for vertical communication in logistic informatics systems  

Microsoft Academic Search

Logistic systems play a crucial role in organization and management of every large enterprise. One very important issue is a vertical communication between localized on factory floor level data sources and business application level logistic systems. OPC UA allows for creating flexible and scalable vertical communication interface. Many interconnection problems related with communication between control and business level of IT

R. Cupek; A. Maka

2010-01-01

398

Fabrication of vertical nanowire resonators for aerosol exposure assessment  

NASA Astrophysics Data System (ADS)

Vertical silicon nanowire (SiNW) resonators are designed and fabricated in order to assess exposure to aerosol nanoparticles (NPs). To realize SiNW arrays, nanolithography and inductively coupled plasma (ICP) deep reactive ion etching (DRIE) at cryogenic temperature are utilized in a top-down fabrication of SiNW arrays which have high aspect ratios (i.e., up to 34). For nanolithography process, a resist film thickness of 350 nm is applied in a vacuum contact mode to serve as a mask. A pattern including various diameters and distances for creating pillars is used (i.e., 400 nm up to 5 ?m). In dry etching process, the etch rate is set high of 1.5 ?m/min to avoid underetching. The etch profiles of Si wires can be controlled aiming to have either perpendicularly, negatively or positively profiled sidewalls by adjusting the etching parameters (e.g., temperature and oxygen content). Moreover, to further miniaturize the wire, multiple sacrificial thermal oxidations and subsequent oxide stripping are used yielding SiNW arrays of 650 nm in diameter and 40 ?m in length. In the resonant frequency test, a piezoelectric shear actuator is integrated with the SiNWs inside a scanning electron microscope (SEM) chamber. The observation of the SiNW deflections are performed and viewed from the topside of the SiNWs to reduce the measurement redundancy. Having a high deflection of ~10 ?m during its resonant frequency of 452 kHz and a low mass of 31 pg, the proposed SiNW is potential for assisting the development of a portable aerosol resonant sensor.

Merzsch, Stephan; Wasisto, Hutomo Suryo; Stranz, Andrej; Hinze, Peter; Weimann, Thomas; Peiner, Erwin; Waag, Andreas

2013-05-01

399

Spray Gun With Constant Mixing Ratio  

NASA Technical Reports Server (NTRS)

Conceptual mechanism mounted in handle of spray gun maintains constant ratio between volumetric flow rates in two channels leading to spray head. With mechanism, possible to keep flow ratio near 1:1 (or another desired ratio) over range of temperatures, orifice or channel sizes, or clogging conditions.

Simpson, William G.

1987-01-01

400

Bidding ratios to predict highway project costs  

Microsoft Academic Search

Purpose – Ratios were constructed using bidding data for highway construction projects in Texas to study whether there are useful patterns in project bids that are indicators of the project completion cost. The use of the ratios to improve predictions of completed project cost was studied. Design\\/methodology\\/approach – Ratios were calculated relating the second lowest bid, mean bid, and maximum

Trefor P. Williams

2005-01-01

401

A dynamic analysis of stock price ratios  

Microsoft Academic Search

Stock price ratios have long been used by finance practitioners as a relative value metric. A popular argument for this widespread use is that stock price ratios tend to revert to their long-run mean so that substantial deviations from historical averages could successfully be arbitraged away. In this work, we lay out the theoretical conditions for the ratio of stock

Antoine Giannetti; Ariel Viale

2011-01-01

402

High aspect ratio wrinkles via substrate prestretch.  

PubMed

A non-fractured, high aspect ratio wrinkled surface is successfully fabricated. Building upon recently developed models of the localization transition and the current knowledge of surface failures, the wrinkling mode is stabilized at high strain, doubling the accessible wrinkling aspect ratio to the currently reported value. This high aspect ratio surface provides significant promise for future wrinkle-based applications. PMID:24863587

Chen, Yu-Cheng; Crosby, Alfred J

2014-08-27

403

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

404

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

405

The oceanic vertical pump induced by mesoscale and submesoscale turbulence.  

PubMed

The motivation to study the vertical exchanges of tracers associated with mesoscale eddies is that the mean concentration of most oceanic tracers changes rapidly with depth. Because mesoscale processes may transport these tracers vertically, biogeochemists hypothesized that these vertical exchanges may strongly affect global tracer budgets. This hypothesis has motivated a large number of biogeochemical studies that we review here by focusing on the significant advances that have been achieved and the remaining issues and uncertainties. The main question that emerges concerns the importance of the submesoscales (10 km in the horizontal) in these vertical exchanges. Independently, in the past decade, fluid dynamicists examined the three-dimensional properties of submesoscales generated by a mesoscale (100 km in the horizontal) turbulent eddy field. We review their results and discuss how the vertical exchanges associated with these submesoscales may answer the issues raised by biogeochemical studies and inspire future directions. PMID:21141041

Klein, Patrice; Lapeyre, Guillaume

2009-01-01

406

A novel method for estimating vertical eddy diffusivities using diurnal signals with application to western Long Island Sound  

NASA Astrophysics Data System (ADS)

We present an approach that allows the estimation of vertical eddy diffusivity coefficients from buoy measurements made at two or more depths. By measuring the attenuation and phase lag of a scalar signal generated periodically at the surface as it propagates downwards, the vertical eddy diffusivity coefficients can be calculated as Kv = ??z2/2ln 2(? 2/? 1), where ? 2/? 1 is the ratio of the real amplitudes at frequency ? at the two depths separated by ? z = z2 - z1; as KV = ?? z2/ 2?2, where ? is the phase lag at the frequency ?; or as Kv = i?? z2/ln 2( U2/ U1), where U2/ U1 is the ratio of the complex signal amplitudes at the two depths. The method requires that horizontal fluxes be small at the ? frequency and that the signal-to-noise ratios at the two depths allow the determination of the amplitude and phase of ?. Application of this method to summertime 2004 western Long Island Sound oxygen and temperature buoy measurements at two depths provides a time-series of two-day average vertical eddy diffusivity estimates. Using these eddy diffusivities in conjunction with measured vertical concentration gradients, we obtain a time-series of vertical transport rates for oxygen and heat and estimate mean downward fluxes for June and July as 150-260 mMol m - 2 day - 1 and 100-400 W m - 2 respectively. These estimates are of a similar magnitude to sub-pycnocline O 2 and heat demands of 240 ± 200 mMol m - 2 day - 1 and 180 ± 60 W m - 2 that we infer from simple budgets, implying that vertical transport is significant to both budgets. The eddy coefficients obtained from the independent O 2 and temperature measurements have a 68% correlation, and the O 2 flux estimates show a correlation of 41% to measured rates of change in bottom dissolved oxygen levels. Our results indicate that extended time-series of eddy diffusivity coefficients can be obtained from in situ buoy measurements and the method shows promise as a way to constrain the vertical transport variability in budgets of dissolved materials in estuaries.

McCardell, Grant; O'Donnell, James

2009-06-01

407

Vertical and horizontal transmission drive bacterial invasion.  

PubMed

A huge variety of Arthropod species is infected with endosymbiotic Wolbachia bacteria that manipulate their host's reproduction to invade populations. In addition to vertical transmission from mother to offspring through the egg cytoplasm, it has been demonstrated through phylogenetic analyses and natural transfer experiments that horizontal transmission of Wolbachia (i.e. contagion) can occur between Arthropod hosts. More recently, factors influencing horizontal transfer have also been explored. While it is clear that horizontal transmission between species plays a major role in the evolutionary history of Wolbachia infections among insects, its role in the spread of a new infection through a host population, notably through within-species transfers, remained unknown. In this issue of Molecular Ecology, Kraaijeveld et al. (2011) present the first evidence that horizontal transmission played a key role in the early spread of parthenogenesis-inducing Wolbachia through the parasitoid wasp Leptopilina clavipes. To support their finding, the authors studied genetic variation in three types of markers, including host nuclear DNA, mitochondrial DNA and Wolbachia DNA. Specifically, they examined potential associations between their diversity patterns. No diversity was detected in Wolbachia genes, indicating that a single Wolbachia strain must have infected and spread through L. clavipes. In addition, a correlation between substantial variation in mitochondrial and nuclear genotypes suggested that horizontal transmission played an important role in the current clonal genetic variation in this wasp. Such horizontal transmission could be facilitated by a specific host ecology (e.g. parasitoid wasps sharing the same host resource) and potentially impact co-evolution between host and symbiont. PMID:21884292

Kremer, Natacha; Huigens, Martinus E

2011-09-01

408

'Victoria Crater' from 'Duck Bay' (Vertical Projection)  

NASA Technical Reports Server (NTRS)

NASA's Mars rover Opportunity edged 3.7 meters (12 feet) closer to the top of the 'Duck Bay' alcove along the rim of 'Victoria Crater' during the rover's 952nd Martian day, or sol (overnight Sept. 27 to Sept. 28), and gained this vista of the crater. The rover's navigation camera took the seven exposures combined into this mosaic view of the crater's interior. This crater has been the mission's long-term destination for the past 21 Earth months.

The far side of the crater is about 800 meters (one-half mile) away. The rim of the crater is composed of alternating promontories, rocky points towering approximately 70 meters (230 feet) above the crater floor, and recessed alcoves, such as Duck Bay. The bottom of the crater is covered by sand that has been shaped into ripples by the Martian wind. The rocky cliffs in the foreground have been informally named 'Cape Verde,' on the left, and 'Cabo Frio,' on the right.

Victoria Crater is about five times wider than 'Endurance Crater,' which Opportunity spent six months examining in 2004, and about 40 times wider than 'Eagle Crater,' where Opportunity first landed. The great lure of Victoria is an expectation that the thick stack of geological layers exposed in the crater walls could reveal the record of past environmental conditions over a much greater span of time than Opportunity has read from rocks examined earlier in the mission.

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

2006-01-01

409

Vertical Datums: Unification and time variation  

NASA Astrophysics Data System (ADS)

Estimation of the fundamental geodetic parameter, W0, the potential value of the Gauss-Listing geoid, is required to define the geoid, the best fitting ellipsoid to the geoid and as a means of unification of the vertical datums in use by various mapping agencies throughout the world. Consideration should also be given to the time derivative of W0 given sea-level change etc. Methodologies to quantify W0 include (i) regional studies utilising tide gauge time series, collocated GPS and precise levelling and (ii) global studies using GRACE and satellite altimetry. Within the first approach, GPS analysis enables global isostatic adjustment and other local deformation to be removed from the tide gauge time series. Values of W0 have been recovered annually at each tide gauge location by establishing the geodetic coordinates of the mean sea surface from the tide gauge measurements, GPS and levelling. By reference to a high precision, high-resolution gravity model of the Earth (i.e., EGM2008) annual values of W0 are analysed for the secular trend. The study uses data from 9 UK tide gauges, 1 in France and 25 around the Baltic Sea. In addition the study is used to connect UK and European datums and also to highlight the improvement of EGM2008 compared with EGM96. In the global approach gravity field temporal variation from GRACE and sea-level change from TOPEX/POSEIDON and JASON-1 altimetry are used to determine the temporal variation of W0 on a global scale. The methodology utilises the temporal gravity field variations from the monthly GRACE fields, the change in mean sea-level as inferred from TOPEX/Poseidon and Jason-1 altimetry and geocentre motion from GPS and satellite laser ranging. This study will report and inter-compare results from the two methodologies.

Edwards, S. J.; Dayoub, N.; Moore, P.; Penna, N. T.

2009-12-01

410

Vertical distribution of specific ventilation in normal supine humans measured by oxygen-enhanced proton MRI  

PubMed Central

Specific ventilation (SV) is the ratio of fresh gas entering a lung region divided by its end-expiratory volume. To quantify the vertical (gravitationally dependent) gradient of SV in eight healthy supine subjects, we implemented a novel proton magnetic resonance imaging (MRI) method. Oxygen is used as a contrast agent, which in solution changes the longitudinal relaxation time (T1) in lung tissue. Thus alterations in the MR signal resulting from the regional rise in O2 concentration following a sudden change in inspired O2 reflect SV—lung units with higher SV reach a new equilibrium faster than those with lower SV. We acquired T1-weighted inversion recovery images of a sagittal slice of the supine right lung with a 1.5-T MRI system. Images were voluntarily respiratory gated at functional residual capacity; 20 images were acquired with the subject breathing air and 20 breathing 100% O2, and this cycle was repeated five times. Expired tidal volume was measured simultaneously. The SV maps presented an average spatial fractal dimension of 1.13 ± 0.03. There was a vertical gradient in SV of 0.029 ± 0.012 cm?1, with SV being highest in the dependent lung. Dividing the lung vertically into thirds showed a statistically significant difference in SV, with SV of 0.42 ± 0.14 (mean ± SD), 0.29 ± 0.10, and 0.24 ± 0.08 in the dependent, intermediate, and nondependent regions, respectively (all differences, P < 0.05). This vertical gradient in SV is consistent with the known gravitationally induced deformation of the lung resulting in greater lung expansion in the dependent lung with inspiration. This SV imaging technique can be used to quantify regional SV in the lung with proton MRI. PMID:20930129

Cronin, Matthew V.; Cortney Henderson, A.; Holverda, Sebastiaan; Theilmann, Rebecca J.; Arai, Tatsuya J.; Dubowitz, David J.; Hopkins, Susan R.; Buxton, Richard B.; Kim Prisk, G.

2010-01-01

411

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

412

Formation of curvature singularities on the interface between dielectric liquids in a strong vertical electric field.  

PubMed

The nonlinear dynamics of the interface between two deep dielectric fluids in the presence of a vertical electric field is studied. We consider the limit of a strong external electric field where electrostatic forces dominate over gravitational and capillary forces. The nonlinear integrodifferential equations for the interface motion are derived under the assumption of small interfacial slopes. It is shown in the framework of these equations that, in the generic case, the instability development leads to the formation of root singularities at the interface in a finite time. The interfacial curvature becomes infinite at singular points, while the slope angles remain relatively small. The curvature is negative in the vicinity of singularities if the ratio of the permittivities of the fluids exceeds the inverse ratio of their densities, and it is positive in the opposite case (we consider that the lower fluid is heavier than the upper one). In the intermediate case, the interface evolution equations describe the formation and sharpening of dimples at the interface. The results obtained are applicable for the description of the instability of the interface between two magnetic fluids in a vertical magnetic field. PMID:24032931

Kochurin, Evgeny A; Zubarev, Nikolay M; Zubareva, Olga V

2013-08-01

413

Dense gas vertical diffusion over rough surfaces: results of wind-tunnel studies  

NASA Astrophysics Data System (ADS)

A cooperative program of measurements of vertical diffusion of continuous, dense gas plumes over rough surfaces in neutral boundary layers has been carried out in three wind tunnels in the USA and the UK. The three environmental boundary layer tunnels were at the Chemical Hazards Research Center (CHRC) at the University of Arkansas, the Fluid Modeling Facility (FMF) of the US Environmental Protection Agency in North Carolina, and the Environmental Flow Research Centre (EnFlo) at the University of Surrey. A simple and consistent set of definitions was adopted for the plume variables like plume depth, mean plume transport speed, vertical entrainment velocity, we, and plume Richardson number Ri ?, where Ri 1/2? is a ratio of buoyancy-induced flow velocities to u ?, the upstream-of-source ambient friction velocity. The present experiments focus on how Ri ? affects the ratio w e/u ?. In order to maintain nearly constant Ri ? in distance and time, continuous line sources of dense gas, primarily CO 2, were employed. Good agreement was found among the three tunnels. The results also agree with the classic Prairie grass field experiment for the "passive limit" ( Ri ?=0): w e/u ?=0.6-0.7. For Ri ? up to 20, the results fit the equation w e/u ?=0.65/(1+0.2 Ri ?). For Ri ?>20, molecular diffusion and viscosity effects were apparently quite strong because we was observed to collapse to values nearly commensurate with molecular diffusion alone.

Briggs, G. A.; Britter, R. E.; Hanna, S. R.; Havens, J. A.; Robins, A. G.; Snyder, W. H.

414

Vertical and Horizontal Trust at Work as Predictors of Retirement Intentions: The Finnish Public Sector Study  

PubMed Central

This prospective cohort study aimed to examine the associations of trust towards the supervisor (vertical trust) and trust towards co-workers (horizontal trust) with retirement intentions. The participants were 14 840 women and men working in the municipal sector in 2000–12 (Finnish Public Sector Study). Trust (vertical trust towards the supervisor and horizontal trust towards co-workers) and retirement intentions were assessed in repeated surveys. Multivariable multinomial logistic regression analyses were conducted to assess the association between baseline trust and retirement intentions at 3.7 years of follow-up. Demographic characteristics, health, psychological distress, health risk behaviors, personality factors, and psychosocial factors were included as covariates. Of the participants, 67.0% trusted their supervisor and 54.9% trusted their co-workers. Employees who trusted their supervisor (odds ratio (OR) 0.60, 95% confidence interval (CI) 0.53–0.67) and employees who trusted their co-workers (odds ratio 0.62, 95% confidence interval 0.55–0.70) at baseline were less likely to have strong retirement intentions at follow-up compared to those who did not trust. These associations largely persisted after adjusting for all covariates and taking into account baseline retirement intentions. In conclusion, trust in the supervisor and co-workers predicted retirement intentions. These observational findings suggest that increasing trust in the workplace may contribute to lengthening working careers and preventing early retirement. PMID:25191745

Muurinen, Charlotte; Laine, Matti; Pentti, Jaana; Virtanen, Marianna; Salo, Paula; Kivimäki, Mika; Vahtera, Jussi; Oksanen, Tuula

2014-01-01

415

Effect of arm swing on effective energy during vertical jumping: experimental and simulation study.  

PubMed

Arm swing helps to increase vertical jump height (VJH), in part by a greater hip joint muscle work. The force-velocity relationship has been put forward to explain the increase in hip joint work. Nevertheless, the efficacy ratio, muscle shortening length, and active state might be parameters that affect the effective energy and then VJH. The purpose of this study was to evaluate the influence of arm swing on effective energy in vertical jumping. Eight subjects performed maximal squat jumps with (SJ arm ) and without arm swing (SJ). A simulation model of the musculo-skeletal system was applied. For subjects and simulation, VJH was about 20% higher during SJ arm. In subjects, this was explained by the shoulder joint work (34%) and an increase of L5-S1 joint work (66%). In simulated jump, effective energy increase during SJ arm (+80.74 J) was related to an improvement of the total muscle work and not to the efficacy ratio. The increase in total muscle work was due to anterior deltoid work and to greater erector spinae, biceps femoris, and gluteus work. The greater muscle works were explained by a slower shortening velocity for all the muscles and by a greater shortening length and active state for the biceps femoris. PMID:23301943

Blache, Y; Monteil, K

2013-03-01

416

Longitudinal differences of ionospheric vertical density distribution and equatorial electrodynamics  

NASA Astrophysics Data System (ADS)

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 ˜37°E and 290°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.; Valladares, C. E.; Pfaff, R. F.

2012-07-01

417

Influence of vertical transport on free tropospheric aerosols over the central USA in springtime  

NASA Astrophysics Data System (ADS)

Measurements of the atmospheric aerosol chemical composition during the Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) indicate substantial vertical transport of boundary layer aerosol to the free troposphere over the south-central United States during springtime. Mixing ratios of water-soluble aerosol Ca2+ at 6-12 km altitude exhibited a median mixing ratio of 20 pptv, with 15% of the measurements ? 100 pptv and a maximum of 1235 pptv. In air parcels with enhanced Ca2+, the ratios K+/Ca2+, Mg2+/Ca2+, and Na+/Ca2+ in the bulk aerosol were distinctly characteristic of those in limestone and/or cement. Significantly enhanced mixing ratios of aerosol SO42-, NO3-, and NH4+ were also concomitant with the elevated Ca2+, suggesting transport of both crustal and anthropogenic aerosols to the upper troposphere. The mass concentration of water-soluble aerosol material was in the range 0.1-6 µg m-3 STP, and estimated crustal dust levels were 7-160 µg m-3 STP.

Talbot, R. W.; Dibb, J. E.; Loomis, M. B.

418

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 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.

Lari, Robert J. (Aurora, IL); Praeg, Walter F. (Palos Park, IL); Turner, Larry R. (Naperville, IL); Battles, James E. (Oak Forest, IL); Hull, John R. (Hinsdale, IL); Rote, Donald M. (Lagrange, IL)

1990-01-01

419

A compact vertical scanner for atomic force microscopes.  

PubMed

A compact vertical scanner for an atomic force microscope (AFM) is developed. The vertical scanner is designed to have no interference with the optical microscope for viewing the cantilever. The theoretical stiffness and resonance of the scanner are derived and verified via finite element analysis. An optimal design process that maximizes the resonance frequency is performed. To evaluate the scanner's performance, experiments are performed to evaluate the travel range, resonance frequency, and feedback noise level. In addition, an AFM image using the proposed vertical scanner is generated. PMID:22163492

Park, Jae Hong; Shim, Jaesool; Lee, Dong-Yeon

2010-01-01

420

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

421

Eccentric crank variable compression ratio mechanism  

DOEpatents

A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

Lawrence, Keith Edward (Kobe, JP); Moser, William Elliott (Peoria, IL); Roozenboom, Stephan Donald (Washington, IL); Knox, Kevin Jay (Peoria, IL)

2008-05-13

422

Sex ratio at birth in Croatia: update.  

PubMed

There is strong evidence that the sex ratio at birth is partially determined by environmental and social factors. The modern change in those factors serves as an explanation for the secular decline in sex ratio at birth in most of the industrialized countries. This article is the reexamination of the results from my previous communication in which no trend in sex ratio at birth was established for the Croatian data from 1946 to 2007. The data for the years 2008 to 2011 were added, which didn't result with the detection of a significant change in sex ratio at birth by the regression analysis or by the Box-Jenkins time series analysis. Although the numerous factors associated with the decline in sex ratio at birth did occur during the studied period (e.g. increased exposure to the environmental pollution through food, air and water, the rise of the obesity and diabetes incidence, the economic crisis etc.), it appears that none of them made the measurable impact on sex ratio at birth. Also, the possible marginally significant decline in sex ratio at birth could be the result of a high sex ratio at birth immediately after the World War II. The results of this study caution against rapid generalization of the factors found to influence the sex ratio at birth in the epidemiological and clinical studies on the population level data. PMID:25144988

Pavi?, Dario

2014-06-01

423

Interior of west end entry showing double door, vertical image, ...  

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

Interior of west end entry showing double door, vertical image, view facing northwest - U.S. Naval Base, Pearl Harbor, Prefabricated, Splinterproof Personnel Shelter, Avenue C, near Seventh Street intersection, adjacent to Facility No. 155, Pearl City, Honolulu County, HI

424

8. Detail view (looking east) of pin connection of vertical ...  

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

8. Detail view (looking east) of pin connection of vertical member at the third panel point north from south abutment of Moody Bridge. - Moody Bridge, Spanning South Fork Eel River, Garberville, Humboldt County, CA

425

11. Detail view (looking east) of pin connection of vertical ...  

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

11. Detail view (looking east) of pin connection of vertical tensile members between panels nine end ten of Moody Bridge - Moody Bridge, Spanning South Fork Eel River, Garberville, Humboldt County, CA

426

9. Detail view (looking east) of pin connection of vertical ...  

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

9. Detail view (looking east) of pin connection of vertical tensile members at the fifth panel point north from south abutment of Moody Bridge. - Moody Bridge, Spanning South Fork Eel River, Garberville, Humboldt County, CA

427

13. VIEW OF TOP CHORD CONNECTION, SHOWING DIAGONAL AND VERTICAL ...  

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

13. VIEW OF TOP CHORD CONNECTION, SHOWING DIAGONAL AND VERTICAL WEB MEMBERS AND TOP LATERAL BRACING, SOUTHEAST SPAN, LOOKING NORTHEAST - Linden Avenue Bridge, Spanning Purgatoire River on Linden Avenue, Trinidad, Las Animas County, CO

428

GROUND WATER SAMPLING FOR VERTICAL PROFILING OF CONTAMINANTS  

EPA Science Inventory

Accurate delineation of plume boundaries and vertical contaminant distribution are necessary in order to adequately characterize waste sites and determine remedial strategies to be employed. However, it is important to consider the sampling objectives, sampling methods, and sampl...

429

VIEW OF PROCESS DEVELOPMENT PILE (PDP) TANK TOP, WITH VERTICAL ...  

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

VIEW OF PROCESS DEVELOPMENT PILE (PDP) TANK TOP, WITH VERTICAL ELEMENTS IN BACKGROUND, LEVEL 0?, LOOKING NORTHWEST - Physics Assembly Laboratory, Area A/M, Savannah River Site, Aiken, Aiken County, SC

430

VIEW OF PDP TANK TOP, LEVEL 0?, WITH VERTICAL ELEMENTS ...  

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

VIEW OF PDP TANK TOP, LEVEL 0?, WITH VERTICAL ELEMENTS IN BACKGROUND, LTR TANK TOP ON LEFT, AND SHEAVE RACK ELEMENTS AT TOP, LOOKING NORTH - Physics Assembly Laboratory, Area A/M, Savannah River Site, Aiken, Aiken County, SC

431

VIEW OF PDP TANK TOP AT LEVEL 0?, WITH VERTICAL ...  

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

VIEW OF PDP TANK TOP AT LEVEL 0?, WITH VERTICAL ELEMENTS IN BACKGROUND AND PART OF SHEAVE RACK ABOVE THE TANK, LOOKING NORTH - Physics Assembly Laboratory, Area A/M, Savannah River Site, Aiken, Aiken County, SC

432

TRANSMISIÓN VERTICAL DE HTLV-1 EN EL PERÚ  

PubMed Central

La infección por el virus linfotrópico humano de células T tipo 1 (HTLV-1) ha sido descrita en muchas áreas del mundo, como en los países del Caribe, Japón, África, Oceanía y en Sudamérica. En la presente revisión definimos la endemicidad del HTLV-1 en el país, planteando cuatro criterios epidemiológicos. Luego discutimos el tema central de la revisión: la transmisión vertical del HTLV-1, que en nuestro país sería uno de los principales mecanismos de transmisión. Dentro del desarrollo de este aspecto en particular, presentamos una estimación de la tasa de transmisión vertical y los factores de riesgo asociados con la transmisión vertical sobre la base de una revisión exhaustiva de estudios nacionales y extranjeros. Con esta revisión pretendemos dar una primera aproximación al estudio de la trasmisión vertical de HTLV-1, un aspecto poco estudiado en nuestro medio. PMID:21537777

Villaverde, Jorge Alarcón; Romaní, Franco Romaní; Torres, Silvia Montano; Zunt, Joseph R.

2012-01-01

433

Vertical hydrodynamic focusing in an isotropically etched glass microfluidic device  

E-print Network

The development of microfluidic devices has enabled precision control of nanoliter-scale environments and reactions. Vertical hydrodynamic focusing is one possible way to improve the optical performance of these devices ...

Lin, Tony An-tong

2007-01-01

434

INTERIOR OF WEST SPAN LOOKING WEST (SHADOW OF VERTICAL LAPS ...  

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

INTERIOR OF WEST SPAN LOOKING WEST (SHADOW OF VERTICAL LAPS PLACED ON ZONE III; ASPHALT ZONE IX) - Honey Run Bridge, Spanning Butte Creek, bypassed section of Honey Run Road (originally Carr Hill Road), Paradise, Butte County, CA

435

Effect of various training modalities on vertical jump.  

PubMed

The purpose of the present investigation was to compare the effects of weight training, training with weights and plyometrics, and training with weights and the VertiMax on vertical jump. Subjects were 37 intercollegiate athletes assigned to one of four training groups: strength (S), strength-plyometric (P), strength-VertiMax without arms (VNA), and strength-VertiMax with arms (VA). Each group completed a 6-week training program. There were no statistical increases in pre-post vertical jump within all groups. There were no significant differences for posttest vertical jump between the four training groups. Pre- and posttest effect sizes were minimal across all groups. The findings of this study demonstrate that there is no difference in vertical jump among strength training, plyometric training, and jump training over a 6-week timeframe. PMID:19479627

Carlson, Kevin; Magnusen, Marshall; Walters, Peter

2009-01-01

436

10. EYEBAR PIN CONNECTION JOINING VERTICAL SUSPENSION STRINGER WITH LATERAL ...  

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

10. EYEBAR PIN CONNECTION JOINING VERTICAL SUSPENSION STRINGER WITH LATERAL BRACING MEMBERS - Spruce Street Bridge, East Spruce Street, 500 Block, spanning Power Canal, Sault Ste. Marie, Chippewa County, MI

437

1. GENERAL VIEW. OVERHANG, PAINTED RED, HAS VERTICAL SIDING AND ...  

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

1. GENERAL VIEW. OVERHANG, PAINTED RED, HAS VERTICAL SIDING AND FADED PAINTINGS OF FARM ANIMALS: COW, DONKEYS AND HORSE. - De Turck House, Barn, State Route 662 vicinity, Oley Township, Oley, Berks County, PA

438

VERTICAL MIXING OF LAKE SEDIMENTS BY TUBIFICID OLIGOCHAETES  

EPA Science Inventory

Vertical mixing of lake sediments by tubificid oligochaetes was studied in laboratory experiments by using a radioactive (cesium 137 labeled sediment) marker horizon. Results from these experiments were used to develop and test a mathematical model describing tubificid sediment m...

439

Theoretical results of vertical external cavity surface emitting laser (VECSEL)  

Microsoft Academic Search

We calculate the characteristic parameters of 980 nm infrared vertical external cavity surface emitting laser with the KP method and give the result of the relative longitudinal confinement factor, threshold gain and output power.

Chun Feng He; G. G. Lu; X. N. Shan; L. Qin; C. L. Yan; Y. Q. Ning; L. J. Wang

2006-01-01

440

Using computerized cephalometrics to analyze the vertical dimension of occlusion.  

PubMed

A computer program that uses cephalometric analyses for determining the patient's occlusal vertical dimension has recently been introduced. Data generated from this computer implies changes in incisal-pin position for articulated casts. This study evaluated the accuracy of this vertical-dimension program using 24 completely dentate, white male subjects with clinically acceptable occlusal vertical dimensions. A cephalometric radiograph was made, and measurements from the tracing were entered into the computer for analysis. Recommended incisal-pin changes ranged from -11 to +25.3 mm, with a mean change of 8.4 mm for all methods tested. These results showed a low correlation with each subject's clinically determined occlusal vertical dimension. PMID:8240648

Edwards, C L; Richards, M W; Billy, E J; Neilans, L C

1993-01-01

441

6. Detail, vertical guides adjacent to east portal of Tunnel ...  

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

6. Detail, vertical guides adjacent to east portal of Tunnel 28, view to southwest, 135mm lens with electronic flash fill. - Central Pacific Transcontinental Railroad, Tunnel No. 28, Milepost 134.75, Applegate, Placer County, CA

442

Detail of old rain shed (Building No. 43) showing vertical ...  

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

Detail of old rain shed (Building No. 43) showing vertical posts on concrete footing with diagonal timber bracing and wire bracing. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

443

31. View from southeast of vertical gas washer with No. ...  

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

31. View from southeast of vertical gas washer with No. 2 Furnace and dust catcher in background. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

444

Incoherent vertical ion losses during multiturn stacking cooling beam injection  

NASA Astrophysics Data System (ADS)

The efficiency of the multiturn ion injection with electron cooling depends on two parameters, namely, cooling efficiency and ion lifetime. The lifetime of freshly injected ions is usually shorter than the lifetime of strongly cooled stacked ions. Freshly injected ions are lost in the vertical direction because the vertical acceptance of the synchrotron is usually a few times smaller than the horizontal acceptance. Incoherent vertical losses of freshly injected ions arise from their multiple scattering by residual gas atoms and transverse diffusion caused by stack noise. Reduced ion lifetime limits the multiturn injection efficiency. Analytical estimations and BETACOOL-based numerical evaluations of the vertical ion losses during multiturn injection are presented in comparison with the experimental data obtained at the HIMAC synchrotron and the S-LSR storage ring.

Syresin, E. M.

2014-07-01

445

19. INTERIOR VIEW OF SIXTH FLOOR AREA ABOVE VERTICAL STORAGE ...  

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

19. INTERIOR VIEW OF SIXTH FLOOR AREA ABOVE VERTICAL STORAGE BINS, SHOWING CONVEYOR DISTRIBUTION SYSTEM, LOOKING SOUTHWEST - Sperry Corn Elevator Complex, Weber Avenue (North side), West of Edison Street, Stockton, San Joaquin County, CA

446

20. INTERIOR VIEW OF SIXTH FLOOR AREA ABOVE VERTICAL STORAGE ...  

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

20. INTERIOR VIEW OF SIXTH FLOOR AREA ABOVE VERTICAL STORAGE BINS, SHOWING CONVEYOR DISTRIBUTION SYSTEM, LOOKING NORTHEAST - Sperry Corn Elevator Complex, Weber Avenue (North side), West of Edison Street, Stockton, San Joaquin County, CA

447

Vertical velocity in oceanic convection off tropical Australia  

E-print Network

Time series of 1 Hz vertical velocity data collected during penetrations by research aircraft of oceanic cumulonimbus clouds near tropical Australia as part of the Equatorial Mesoscale Experiment (EMEX) are analyzed for updraft and downdraft events...

Lucas, Christopher

2012-06-07

448

Assessing and Predicting Vertical Intent for Web , Ronan Cummins2  

E-print Network

, especially as the vertical items are hidden), this assumption eases the assessment burden, and reflects, discussion, scholar, wiki) and contains 320 web topics. Assessors were anonymous online respondents who

Lalmas, Mounia

449

An ecological perceptual aid for precision vertical landings  

E-print Network

Pilots of vertical landing vehicles face numerous control challenges which often involve the loss of outside visual perceptual cues or the control of flight parameters within tight constraints. These challenges are often ...

Smith, Cristin Anne

2006-01-01

450

6. Detail of west abutment, upper and lower chords, vertical ...  

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

6. Detail of west abutment, upper and lower chords, vertical and diagonal members - St. Louis Avenue Viaduct, Spanning Kansas City Terminal Railroad at Beardsley Road & Bluff Street, Kansas City, Jackson County, MO

451

Parameterization of the vertical velocity equation for shallow cumulus clouds  

E-print Network

. This result is at odds with the parameterized14 vertical velocity equation in the literature as it employs into account by assuming36 that a fixed prescribed fraction of the mass flux can reach the next model level37

Siebesma, Pier

452

Vertical Discretization of Hydrostatic Primitive Equations with Finite Element Method  

NASA Astrophysics Data System (ADS)

A vertical finite element (VFE) discretization of hydrostatic primitive equations is developed for the dynamical core of a numerical weather prediction (NWP) system at KIAPS, which is horizontally discretized by a spectral element on a cubed-sphere grid. The governing equations are discretized on a hybrid pressure-based vertical coordinate [1]. Compared with a vertical finite difference (VFD) discretization, which is only first order accurate for non-uniform grids, the VFE has many advantages such that it gives more accurate results, all variables are defined in the same full level, the level of vertical noise might be reduced [2], and it is easily coupled with existing physics packages, developed for a Lorentz staggering grid system. Due to these reasons, we adopted the VFE scheme presented by Untch [2] for the vertical discretization. Instead of using semi-Lagrangian and semi-implicit schemes of ECMWF, we use the Eulerian equations and second-order Runge-Kutta scheme as the first step in implementing the VFE for the dynamical core of the KIAPS's NWP model. Since the Eulerian hydrostatic equations are used in this study, both integral and derivative operators are required to implement the VFE using the Galerkin method with b-splines as basis functions. To compare the accuracy of the VFE with the VFD, the two-dimensional test case of mountain waves is used where physical configuration and initial conditions are the same as that of Durran [3]. In this case, the horizontal and vertical velocities obtained by the analytical solution, VFD, VFE-linear and VFE-cubic are compared to understand their numerical features and the vertical flux of horizontal momentum is also presented as the measurement of solution accuracy since it is sensitive to errors in a solution [3]. It is shown that the VFE with a cubic b-spline function is more accurate than the VFD and VFE with a linear b-spline function as the vertical flux is closer to unity, which will be presented in the conference. Reference Simmons, A. J., Burridge, D. M., 1981: An energy and angular momentum conserving vertical finite difference scheme and hybrid vertical coordinates. Mon. Wea. Rev., 109, 758-766. Untch, A., Hortal, M., 2004: A finite-element schemes for the vertical discretization of the semi-Lagrangian version of the ECMWF forecast model. Q. J. R. Meteorol. Soc., 130, 1505-1530. Durran, D. R., Klemp, J. B., 1983: A compressible model for the simulation of moist mountain waves. Mon. Wea. Rev., 111, 2341-2361.

Yi, Tae-Hyeong; Park, Ja-Rin

2014-05-01

453

Short Communication Vertical distribution of barnacle larvae at a fixed nearshore station in southern  

E-print Network

Short Communication Vertical distribution of barnacle larvae at a fixed nearshore station Keywords: Barnacle larvae Chthamalus Balanus vertical distribution stage-specific southern California among populations. We present observations on the vertical distribution of barnacle larvae from southern

Pineda, Jesús

454

Vertical longitudinal magnetoresistance of semiconductor superlattices Yu. A. Pusep,1,2  

E-print Network

Vertical longitudinal magnetoresistance of semiconductor superlattices Yu. A. Pusep,1,2 G. M. Gusev manuscript received 19 January 2001; published 2 April 2001 Vertical longitudinal magnetoresistance VLMR the surface conductiv- ity contributes significantly. Moreover, the vertical longitudinal magnetoresistance

Gusev, Guennady

455

Vertical-plane pendulum absorbers for minimizing helicopter vibratory loads  

NASA Technical Reports Server (NTRS)

The use of pendulum dynamic absorbers mounted on the blade root and operating in the vertical plane to minimize helicopter vibratory loads was discussed. A qualitative description was given of the concept of the dynamic absorbers and some results of analytical studies showing the degree of reduction in vibratory loads attainable are presented. Operational experience of vertical plane dynamic absorbers on the OH-6A helicopter is also discussed.

Amer, K. B.; Neff, J. R.

1974-01-01

456

VERTICAL TRACK MODULUS TESTING ON BNSF'S HEAVY HAUL COAL LINE  

Microsoft Academic Search

A joint project between the University of Nebraska-Lincoln and the Federal Railroad Administration seeks to create a system that can estimate Vertical Track Modulus (VTM) along the track and at revenue speed. The system consists of a loaded hopper with a camera\\/laser sensor to detect the vertical deflection of the rail relative to the wheel\\/rail contact point. This measurement is

Sheng Lu; Cory Hogan; Brock Minert; Richard Arnold; Shane Farritor; William Seeger; Michael Oliver; Henry Lees; David Thornton; Mahmood Fateh; Gary Carr

457

The vertical–horizontal illusion in hemi-spatial neglect  

Microsoft Academic Search

The vertical–horizontal illusion is a robust phenomenon of length mis-estimation between two orthogonal lines. This illusion involves an anisotropy component that makes the vertical line appear longer than the horizontal one and a bisection component that makes the bisected line shorter than the bisecting one. Six patients presenting a moderate left hemi-neglect (N-patients) were compared to four right brain damaged

M. de Montalembert; P. Mamassian

2010-01-01

458

Spatial Cognition and the Processing of Verticality in Underground Environments  

Microsoft Academic Search

Verticality is a relevant feature in many environments. Despite its relevance, little is known about how it is processed.\\u000a In work conducted with the RATP, we approached this problem by comparing three forms of graphic aids intended to provide information\\u000a about the vertical dimension of subway stations. These graphic representations were : floorplans of each level of the station,\\u000a the

Sylvie Fontaine

2001-01-01

459

Vertical electron content from ionograms in real time  

Microsoft Academic Search

A new technique for calculating the vertical total electron content (TEC) from ground-based ionosonde measurements is introduced. The ionogram provides the information to directly calculate the vertical electron density profile up to the peak of the F2 layer. The profile above the peak is approximated by an alpha-Chapman function with a scale height that is derived from the profile shape

Xueqin Huang; Bodo W. Reinisch

2001-01-01

460

Evaluation of the vertical axis wind turbine at DREO  

Microsoft Academic Search

A Vertical Axis Wind Turbine-Battery Storage System was installed at the Defence Research Establishment Ottawa (DREO) in December 1975 and was operated for three years. The system was instrumented to control and monitor its operation and performance. This report deals with an evaluation study of a Vertical Axis Wind Turbine-Battery Storage System for a low-power unattended power source. The System's

H. R. Braun; D. J. Bristow; S. J. Wake

1980-01-01

461

Influence of gravity on cat vertical vestibulo-ocular reflex  

Microsoft Academic Search

The vertical vestibulo-ocular reflex (VOR) was recorded in cats using electro-oculography during sinusoidal angular pitch. Peak stimulus velocity was 50°\\/s over a frequency range from 0.01 to 4.0 Hz. To test the effect of gravity on the vertical VOR, the animal was pitched while sitting upright or lying on its side. Upright pitch changed the cat's orientation relative to gravity,

D. L. Tomko; C. Wall; F. R. Robinson; J. P. Staab

1988-01-01

462

Vertical crustal motions from the DORIS space-geodesy system  

Microsoft Academic Search

Five years (1993-1997) of DORIS data on the SPOT and Topex-Poseidon satellites have been analyzed to estimate vertical motions at 33 sites of the permanent DORIS network. Rates have been determined assuming constant velocity over the 5-year time span. Except for a few stations, vertical rates are lower than 5 mm\\/yr. Comparison with solutions provided by GPS, SLR or VLBI

Laurent Soudarin; Jean-François Crétaux; Anny Cazenave

1999-01-01

463

Vertical coherency function model of spatial ground motion  

NASA Astrophysics Data System (ADS)

Many studies have focused on horizontal ground motion, resulting in many coherency functions for horizontal ground motion while neglecting related problems arising from vertical ground motion. However, seismic events have demonstrated that the vertical components of ground motion sometimes govern the ultimate failure of structures. In this paper, a vertical coherency function model of spatial ground motion is proposed based on the Hao model and SMART 1 array records, and the validity of the model is demonstrated. The vertical coherency function model of spatial ground motion is also compared with the horizontal coherency function model, indicating that neither model exhibits isotropic characteristics. The value of the vertical coherency function has little correlation with that of the horizontal coherency function. However, the coherence of the vertical ground motion between a pair of stations decreases with their projection distance and the frequency of the ground motion. When the projection distance in the wave direction is greater than 800 meters, the coherency between the two points can be neglected.

Ye, Jihong; Pan, Jinlong; Liu, Xianming

2011-09-01

464

Comparing Reading Speed for Horizontal and Vertical English Text  

PubMed Central

There are three formats for arranging English text for vertical reading—upright letters arranged vertically (marquee), and horizontal text rotated 90° clockwise or counterclockwise. Previous research has shown that reading is slower for all three vertical formats than for horizontal text, with marquee being slowest. It has been proposed that the size of the visual span—the number of letters recognized with high accuracy without moving the eyes—is a visual factor limiting reading speed. We predicted that reduced visual-span size would be correlated with the slower reading for the three vertical formats. We tested this prediction with uppercase and lowercase letters. Reading performance was measured using two presentation methods: RSVP (Rapid Serial Visual Presentation) and flashcard (a block of text on four lines). On average, reading speed for horizontal text was 139% faster than marquee text and 81% faster than the rotated texts. Size of the visual span was highly correlated with changes in reading speed for both lowercase and uppercase letters and for both RSVP and flashcard reading. Our results are consistent with the view that slower reading of vertical text is due to a decrease in the size of the visual span for vertical reading. PMID:20462322

Yu, Deyue; Park, Heejung; Gerold, David; Legge, Gordon E.

2010-01-01

465

A new approach to the treatment of congenital vertical talus  

PubMed Central

Congenital vertical talus is an uncommon foot deformity that is present at birth and results in a rigid flatfoot deformity. Left untreated the deformity can result in pain and disability. Though the exact etiology of vertical talus is unknown, an increasing number of cases have been shown to have a genetic cause. Approximately 50% of all cases of vertical talus are associated with other neuromuscular abnormalities or known genetic syndromes. The remaining 50% of cases were once thought to be idiopathic in nature. However, there is increasing evidence that many of these cases are related to single gene defects. Most patients with vertical talus have been treated with major reconstructive surgeries that are fraught with complications such as wound necrosis, talar necrosis, undercorrection of the deformity, stiffness of the ankle and subtalar joint, and the eventual need for multiple operative procedures. Recently, a new approach to vertical talus that consists of serial casting and minimal surgery has resulted in excellent correction in the short-term. Longer follow-up will be necessary to ensure maintenance of correction with this new technique. A less invasive approach to the correction of vertical talus may provide more favorable long-term outcomes than more extensive surgery as has been shown to be true for clubfoot outcomes. PMID:19308490

Alaee, Farhang; Boehm, Stephanie

2007-01-01

466

Low-Voltage Organic Electronics Based on a Gate-Tunable Injection Barrier in Vertical graphene-organic Semiconductor Heterostructures.  

PubMed

The vertical integration of graphene with inorganic semiconductors, oxide semiconductors, and newly emerging layered materials has recently been demonstrated as a promising route toward novel electronic and optoelectronic devices. Here, we report organic thin film transistors based on vertical heterojunctions of graphene and organic semiconductors. In these thin heterostructure devices, current modulation is accomplished by tuning of the injection barriers at the semiconductor/graphene interface with the application of a gate voltage. N-channel devices fabricated with a thin layer of C60 show a room temperature on/off ratio >10(4) and current density of up to 44 mAcm(-2). Because of the ultrashort channel intrinsic to the vertical structure, the device is fully operational at a driving voltage of 200 mV. A complementary p-channel device is also investigated, and a logic inverter based on two complementary transistors is demonstrated. The vertical integration of graphene with organic semiconductors via simple, scalable, and low-temperature fabrication processes opens up new opportunities to realize flexible, transparent organic electronic, and optoelectronic devices. PMID:25517922

Hlaing, Htay; Kim, Chang-Hyun; Carta, Fabio; Nam, Chang-Yong; Barton, Rob A; Petrone, Nicholas; Hone, James; Kymissis, Ioannis

2015-01-14

467

Vertical structure of aerosols, temperature, and moisture associated with an intense African dust event observed over the eastern Caribbean  

NASA Astrophysics Data System (ADS)

unusually intense African dust event affected a large area of the western Atlantic and eastern Caribbean in early April 2010. Measurements made east of Barbados from the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter research aircraft are used to characterize particle size distributions; vertical distributions of aerosols, temperature, and moisture; and processes leading to the observed stratification in the boundary layer. The vertical profiles of various aerosol characterizations were similar on both days and show three layers with distinct aerosol and thermodynamic characteristics: the Saharan Air Layer (SAL; ~2.2 km ± 500 m), a subcloud layer (SCL; surface to ~500 m), and an intermediate layer extending between them. The SAL and SCL display well-mixed aerosol and thermodynamic characteristics; but the most significant horizontal and vertical variations in aerosols and thermodynamics occur in the intermediate layer. The aerosol variability observed in the intermediate layer is likely associated with modification by shallow cumulus convection occurring sometime in the prior history of the air mass as it is advected across the Atlantic. A comparison of the thermodynamic structure observed in the event from its origin over Africa with that when it reached Barbados indicates that the lower part of the SAL was moistened by surface fluxes as the air mass was advected across the Atlantic. Mixing diagrams using aerosol concentrations and water vapor mixing ratios as conserved parameters provide insight into the vertical transports and mixing processes that may explain the observed aerosol and thermodynamic variability in each layer.

Jung, Eunsil; Albrecht, Bruce; Prospero, Joseph M.; Jonsson, Haflidi H.; Kreidenweis, Sonia M.

2013-05-01

468

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

469

A low aspect ratio tokamak transmutation system  

Microsoft Academic Search

A low aspect ratio tokamak transmutation system is proposed as an alternative application of fusion energy on the basis of a review of previous studies. This system includes: (1) a low aspect ratio tokamak as fusion neutron driver, (2) a radioactivity-clean nuclear power system as blanket, and (3) a novel concept of liquid metal centre conductor post as part of

L. J. Qiu; Y. C. Wu; B. J. Xiao; Q. Xu; Q. Y. Huang; B. Wu; Y. X. Chen; W. N. Xu; Y. P. Chen; X. P. Liu

2000-01-01