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1

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

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

2

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.

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

3

Cup-To-Disc Ratio Of The Optic Disc By Image Analysis To Assist Diagnosis Of Glaucoma Risk And Evolution  

NASA Astrophysics Data System (ADS)

This work builds an image analysis algorithm to give assistance in the cup to disc ratio estimation of glaucomatous eyes. Often the contours of both the optic cup and disc are faint and intersected by entangled veins that make it difficult to draw their silhouettes. The algorithm, which takes into account the viewing conditions of the specialist, is based on the information of color, the color differences between neighbor pixels and the geometry of the areas involved.

Valencia, Edison; Millán, María S.; Kotynski, Rafal

2006-10-01

4

ARGALI: an automatic cup-to-disc ratio measurement system for glaucoma detection and AnaLysIs framework  

NASA Astrophysics Data System (ADS)

Glaucoma is an irreversible ocular disease leading to permanent blindness. However, early detection can be effective in slowing or halting the progression of the disease. Physiologically, glaucoma progression is quantified by increased excavation of the optic cup. This progression can be quantified in retinal fundus images via the optic cup to disc ratio (CDR), since in increased glaucomatous neuropathy, the relative size of the optic cup to the optic disc is increased. The ARGALI framework constitutes of various segmentation approaches employing level set, color intensity thresholds and ellipse fitting for the extraction of the optic cup and disc from retinal images as preliminary steps. Following this, different combinations of the obtained results are then utilized to calculate the corresponding CDR values. The individual results are subsequently fused using a neural network. The learning function of the neural network is trained with a set of 100 retinal images For testing, a separate set 40 images is then used to compare the obtained CDR against a clinically graded CDR, and it is shown that the neural network-based result performs better than the individual components, with 96% of the results within intra-observer variability. The results indicate good promise for the further development of ARGALI as a tool for the early detection of glaucoma.

Liu, J.; Wong, D. W. K.; Lim, J. H.; Li, H.; Tan, N. M.; Wong, T. Y.

2009-02-01

5

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

NASA Astrophysics Data System (ADS)

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

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

2009-02-01

6

Total mixing ratios. [molecular and atomic density vertical distribution correlation  

NASA Technical Reports Server (NTRS)

The total mixing ratio of an atom, which may be contained in any number of different molecules, is derived as a function of altitude for the earth's mesosphere and stratosphere. It is shown that the total mixing ratio of most atoms is constant; for an escaping gas, such as hydrogen, the ratio decreases with altitude, whereas the mixing ratios of atoms deposited by meteors increase with altitude. The analysis shows that by using total mixing ratios, the individual mixing ratios at a certain altitude can be related to those of another altitude without any restrictions on chemical lifetimes.

Thomas, R. J.

1974-01-01

7

Peak Horizontal-to-Vertical Acceleration Ratio and Local Amplification of Strong Ground Motion  

Microsoft Academic Search

Residuals of the peak horizontal acceleration for site-independent attenuation relations are shown to have weak positive correlation with the average observed peak horizontal\\/vertical acceleration ratio (q) at the recording site. This ratio systematically increases as the hardness of the soil decreases. Taking the average observed q at the recording station into account reduces the scatter of data slightly in fitting

Snježana Markuši?; Marijan Herak; Davorka Herak; Ines Ivan?i?

2002-01-01

8

Slip Ratios and Friction Factors in the Bubble Flow Regime in Vertical Tubes.  

National Technical Information Service (NTIS)

Slip ratios in the vertical bubble flow regime were measured in adiabatic air-water and steam-water flow. The experimental data confirm that the slip ratio in bubble flow may be represented by two terms. The first term is due to the relative velocity betw...

D. Malnes

1966-01-01

9

High-aspect-ratio Si vertical micromirror arrays for optical switching  

Microsoft Academic Search

Arrays of bulk-micromachined high-aspect-ratio vertical Si mirrors were designed, fabricated, and characterized for optical switching applications. These 50-?m-tall vertical mirrors were fabricated by the deep-etch shallow-diffusion process. The released Si mirrors have smooth sidewalls with 5-nm surface roughness. An electrostatic comb drive applied to actuate the mirrors which were supported by folded or serpentine beams. For 800-?m-long, 3-?m-wide, and 50-?m-thick

W.-H. Juan; S. W. Pang

1998-01-01

10

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

11

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

12

Determining dynamical controls on vertical motion near Hawaii using isotope ratios in water  

NASA Astrophysics Data System (ADS)

Measurements near Hawaii show a relationship between the strength of shallow convection and the formation of residual layers, which can regulate moisture transport between the subtropical boundary layer and free troposphere for multiple days at a time. Since moisture in the free troposphere exerts important feedbacks on climate in both vapor and cloud form, understanding the processes that control its vertical transport in the atmosphere is critical. This study examines the role of large-scale dynamics in modifying convection and vertical mixing near Hawaii using stable isotopes in water. Because the ratios of heavy-to-light isotopes of oxygen and hydrogen are sensitive to water cycle phase changes, boundary layer and free tropospheric air masses may be readily distinguished by their isotopic composition, and the effects of local cloud processing and airmass mixing may be quantified. Consequently, by examining simultaneous changes in the vapor mixing ratios and isotope ratios measured at Mauna Loa Observatory--which typically lies above the trade wind temperature inversion at night (3400 m)--the speed and nature of the transition from free tropospheric to boundary layer air can be characterized each day. In this manner, periods of gradual mixing are differentiated from periods of rapid undiluted updrafts against an ever-changing free tropospheric background modified by large-scale transport and subsidence. The strength of convection is further characterized by quantifying the fraction of boundary layer air to reach the Observatory and the time it remains aloft. We find persistent periods of high daytime humidity and isotopic enrichment at Mauna Loa are associated with regionally coherent convective patterns that align with southwesterly wind trajectories. Cloud differences between these and persistently dry and depleted periods are investigated.

Raudzens Bailey, A.; Noone, D. C.; Nusbaumer, J. M.; Toohey, D. W.

2013-12-01

13

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

NASA Astrophysics Data System (ADS)

We report on techniques for catalytic synthesis of rigid, high-aspect-ratio, vertically aligned carbon nanofibres by dc plasma enhanced chemical vapour deposition that are tailored for applications that require arrays of individual fibres that feature long fibre lengths (up to 20 µm) such as scanning probe microscopy, penetrant cell and tissue probing arrays and mechanical insertion approaches for gene delivery to cell cultures. We demonstrate that the definition of catalyst nanoparticles is the critical step that enables growth of individual, long-length fibres and discuss methods for catalyst particle preparation that allow the growth of individual isolated nanofibres from catalyst dots with diameters as large as 500 nm. This development enables photolithographic definition of catalyst and therefore the inexpensive, large-scale production of such arrays.

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

2003-09-01

14

Magnetic field alignment of randomly oriented, high aspect ratio silicon microwires into vertically oriented arrays.  

PubMed

External magnetic fields have been used to vertically align ensembles of silicon microwires coated with ferromagnetic nickel films. X-ray diffraction and image analysis techniques were used to quantify the degree of vertical orientation of the microwires. The degree of vertical alignment and the minimum field strength required for alignment were evaluated as a function of the wire length, coating thickness, magnetic history, and substrate surface properties. Nearly 100% of 100 ?m long, 2 ?m diameter, Si microwires that had been coated with 300 nm of Ni could be vertically aligned by a 300 G magnetic field. For wires ranging from 40 to 60 ?m in length, as the length of the wire increased, a higher degree of alignment was observed at lower field strengths, consistent with an increase in the available magnetic torque. Microwires that had been exposed to a magnetic sweep up to 300 G remained magnetized and, therefore, aligned more readily during subsequent magnetic field alignment sweeps. Alignment of the Ni-coated Si microwires occurred at lower field strengths on hydrophilic Si substrates than on hydrophobic Si substrates. The magnetic field alignment approach provides a pathway for the directed assembly of solution-grown semiconductor wires into vertical arrays, with potential applications in solar cells as well as in other electronic devices that utilize nano- and microscale components as active elements. PMID:23083440

Beardslee, Joseph A; Sadtler, Bryce; Lewis, Nathan S

2012-11-27

15

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

16

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

PubMed

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

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

2013-10-18

17

Difference of Horizontal-to-Vertical (H/V) Spectral Ratios of Microtremors and Earthquake Motions: Theory and Observation  

NASA Astrophysics Data System (ADS)

Horizontal-to-vertical spectral ratios (HVRs) of microtremors have been traditionally interpreted theoretically as representing the Rayleigh wave ellipticity or just utilized a convenient tool to extract predominant periods of ground. However, based on the diffuse field theory (Sánchez-Sesma et al., 2011) the microtremor H/V spectral ratios (MHVRs) correspond to the square root of the ratio of the imaginary part of horizontal displacement for a horizontally applied unit harmonic load and the imaginary part of vertical displacement for a vertically applied unit load. The same diffuse field concept leads us to derive a simple formula for earthquake HVRs (EHVRs), that is, the ratio of the horizontal motion on the surface for a vertical incidence of S wave divided by the vertical motion on the surface for a vertical incidence of P wave with a fixed coefficient (Kawase et al., 2011). The difference for EHVRs comes from the fact that primary contribution of earthquake motions would be of plane body waves. Traditionally EHVRs are interpreted as the responses of inclined SV wave incidence only for their S wave portions. Without these compact theoretical solutions, EHVRs and MHVRs are either considered to be very similar/equivalent, or totally different in the previous studies. With these theoretical solutions we need to re-focus our attention on the difference of HVRs. Thus we have compared here HVRs at several dozens of strong motion stations in Japan. When we compared observed HVRs we found that EHVRs tend to be higher in general than the MHVRs, especially around their peaks. As previously reported, their general shapes share the common features. Especially their fundamental peak and trough frequencies show quite a good match to each other. However, peaks in EHVRs in the higher frequency range would not show up in MHVRs. When we calculated theoretical HVRs separately at these target sites, their basic characteristics correspond to these observed differences. At this stage of research we found that the underground structures that are optimized for EHVRs would not explain perfectly MHVRs. This strongly suggests that we need to optimize underground structures to explain both EHVRs and MHVRs at the same time.

Kawase, H.; Nagashima, F.; Matsushima, S.; Sanchez-Sesma, F. J.

2013-05-01

18

Alteration of the equal settling ratio of fine particles by vertically-oscillating water  

Microsoft Academic Search

An equal settling ratio is an important factor in estimating particle separation accuracy. However, this factor is often calculated using the settling velocity in stationary water, there are no examples of calculation of the equal settling ratio in an actual separator. This is difficult because particle movement in a separator is very complicated, and even simple periodic motions, such as

Tatsuya Oki; Mikio Kobayashi; Shuji Owada; Daiki Matsuura

2007-01-01

19

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

20

Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan.  

PubMed

Using a sector-field ICP-MS the vertical distributions of the (99)Tc concentration and (99)Tc/(137)Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The (99)Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m(3), no greater than the estimated background level. Relatively high (99)Tc/(137)Cs activity ratios (10-12 × 10(-4)) would be caused by the inflow of the high-(99)Tc/(137)Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The (99)Tc concentration and the (99)Tc/(137)Cs activity ratio in water column showed gradual decreases with depth. Our results implied that (99)Tc behaves in a more conservative manner than (137)Cs in marine environments. PMID:21555170

Nakanishi, Takahiro; Zheng, Jian; Aono, Tatsuo; Yamada, Masatoshi; Kusakabe, Masashi

2011-08-01

21

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

22

Vertical and meridional distributions of the atmospheric CO2 mixing ratio between northern midlatitudes and southern subtropics  

NASA Astrophysics Data System (ADS)

The atmospheric CO2 mixing ratio was measured using a continuous measurement system onboard a Gulfstream-II aircraft between the northern midlatitudes and the southern subtropics during the Biomass Burning and Lightning Experiment Phase A (BIBLE A) campaign in September-October 1998. The vertical distribution of CO2 over tropical regions was almost constant from the surface to an altitude of 13 km. CO2 enhancements from biomass burning and oceanic release were observed in the tropical boundary layer. Measurements in the upper troposphere indicate interhemispheric exchange was effectively suppressed between 2°N-7°N. Interhemispheric transport of air in the upper troposphere was suppressed effectively in this region. The CO2 mixing ratios in the Northern and Southern Hemispheres were almost constant, with an average value of about 365 parts per million (ppm) and 366 ppm, respectively. The correlation between the CO2 and NOy mixing ratios observed north of 7°N was apparently different from that obtained south of 2°N. This fact strongly supports the result that the north-south boundary in the upper troposphere during BIBLE A was located around 2°N-7°N as the boundary is not necessary a permanent feature.

Machida, T.; Kita, K.; Kondo, Y.; Blake, D.; Kawakami, S.; Inoue, G.; Ogawa, T.

2003-02-01

23

Vertical and meridional distributions of the atmospheric CO2 mixing ratio between northern midlatitudes and southern subtropics  

NASA Astrophysics Data System (ADS)

The atmospheric CO2 mixing ratio was measured using a continuous measurement system onboard a Gulfstream-II aircraft between the northern midlatitudes and the southern subtropics during the Biomass Burning and Lightning Experiment Phase A (BIBLE A) campaign in September-October 1998. The vertical distribution of CO2 over tropical regions was almost constant from the surface to an altitude of 13 km. CO2 enhancements from biomass burning and oceanic release were observed in the tropical boundary layer. Measurements in the upper troposphere indicate interhemispheric exchange was effectively suppressed between 2°N-7°N. Interhemispheric transport of air in the upper troposphere was suppressed effectively in this region. The CO2 mixing ratios in the Northern and Southern Hemispheres were almost constant, with an average value of about 365 parts per million (ppm) and 366 ppm, respectively. The correlation between the CO2 and NOy mixing ratios observed north of 7°N was apparently different from that obtained south of 2°N. This fact strongly supports the result that the north-south boundary in the upper troposphere during BIBLE A was located around 2°N-7°N as the boundary is not necessary a permanent feature.

Machida, T.; Kita, K.; Kondo, Y.; Blake, D.; Kawakami, S.; Inoue, G.; Ogawa, T.

2002-02-01

24

Investigation on the effect of filling ratio on the steady-state heat transfer performance of a vertical two-phase closed thermosyphon  

Microsoft Academic Search

Filling ratio of the working fluid has a predominant effect on the heat transfer characteristics of a two-phase closed thermosyphon (TPCT). A comprehensive model is developed to investigate the effect of filling ratio on the steady-state heat transfer performance of a vertical TPCT. Three types of flow pattern and two types of transition, according to the distribution of liquid film

B. Jiao; L. M. Qiu; X. B. Zhang; Y. Zhang

2008-01-01

25

Effects of C/Si ratio in fast epitaxial growth of 4H SiC(0 0 0 1) by vertical hot-wall chemical vapor deposition  

NASA Astrophysics Data System (ADS)

The C/Si ratio dependence of growth rate, surface morphology, micropipe closing ratio, doping concentration and deep-level concentration have been investigated in fast epitaxial growth of 4H-SiC (0 0 0 1) epilayers by chemical vapor deposition in a vertical hot-wall reactor. The doping, Z 1/2 and EH 6/7 centers concentrations of thick epilayers decrease with increasing C/Si ratio of source gases. By adjusting the C/Si ratio at 0.7, specular surface morphology with a low doping concentration of 1×10 13 cm -3 has been obtained at a growth rate of 33 ?m/h, and the concentrations of Z 1/2 and EH 6/7 centers have been kept low, 8×10 12 and 4×10 12 cm -3, respectively.

Fujiwara, H.; Danno, K.; Kimoto, T.; Tojo, T.; Matsunami, H.

2005-08-01

26

Effects of influent C/N ratios on CO2 and CH4 emissions from vertical subsurface flow constructed wetlands treating synthetic municipal wastewater.  

PubMed

Greenhouse gases (GHG) emissions from constructed wetlands (CWs) can mitigate the environmental benefits of nutrient removal because reduced water pollution could be replaced by emission of GHG. Therefore, the GHG (CO(2) and CH(4)) fluxes of vertical subsurface flow constructed wetlands (VSSF CWs) under different influent C/N ratios of synthetic municipal wastewater were analyzed directly by GHG flux measurements, and estimated by carbon mass balance (CMB) over a 12 month period. The VSSF CWs system achieved the highest biological nutrient removal (BNR) efficiency between C/N ratios of 5:1 and 10:1 across all kinds of pollutants. Variation in influent C/N ratios dramatically influenced GHG fluxes from the VSSF CWs system. The GHG flux measured in situ agreed with those predicted by the CMB model and represented relatively low GHG fluxes when C/N ratios were between 2.5:1 and 5:1. It was determined that the optimum C/N ratio is 5:1, at which VSSF CWs can achieve a relatively high BNR efficiency and a low level of GHG flux. PMID:22192587

Yan, Cheng; Zhang, Hui; Li, Bo; Wang, Dong; Zhao, Yongjun; Zheng, Zheng

2012-02-15

27

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

28

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

PubMed

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

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

2014-02-12

29

81 fJ/bit energy-to-data ratio of 850 nm vertical-cavity surface-emitting lasers for optical interconnects  

NASA Astrophysics Data System (ADS)

Extremely energy-efficient oxide-confined high-speed 850 nm vertical-cavity surface-emitting lasers for optical interconnects are presented. Error-free performance at 17 and 25 Gb/s via a 100 m multimode fiber link is demonstrated at record high dissipation-power-efficiencies of up to 69 fJ/bit (<0.1 mW/Gbps) and 99 fJ/bit, respectively. These are the most power efficient high-speed directly modulated light sources reported to date. The total energy-to-data ratio is 83 fJ/bit at 25 °C and reduces to 81 fJ/bit at 55 °C. These results were obtained without adjustment of driving conditions. A high D-factor of 12.0 GHz/(mA)0.5 and a K-factor of 0.41 ns are measured.

Moser, P.; Hofmann, W.; Wolf, P.; Lott, J. A.; Larisch, G.; Payusov, A.; Ledentsov, N. N.; Bimberg, D.

2011-06-01

30

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

31

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

USGS Publications Warehouse

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

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

2010-01-01

32

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

USGS Publications Warehouse

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

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

2011-01-01

33

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

34

A comparative study of vertical flow and free-water surface constructed wetlands for low C/N ratio domestic wastewater treatment and its greenhouse gases emission  

NASA Astrophysics Data System (ADS)

Constructed wetland (CW) systems are reliable, flexible in design, and can be built, operated, and maintained at lower costs compared to conventional methods of chemical treatment. Therefore, CW systems are widely used for controlling water-body eutrophication as an ease-operation and cost-effective ecological technology in developing countries. However, growing attention has been directed to its greenhouse side-effect and global-warming potential in recent years. In this study, two typical constructed wetlands: Vertical flow (VF) and Free-water surface (FWS) constructed wetlands were used not only to compare the nutrients removal performance for treatment of low C/N ratio loading domestic wastewater, but also to investigate and compare their CH4 and N2O greenhouse gases emission characteristics. The results indicated that the VF CW showed a comparatively good performance for nitrogen and phosphorus removal than FWS constructed wetland, which was 98.5, 95.9, 93.2 and 90.7 percent for BOD5, SS, NH4-N and TP under 6 days HRT, respectively. It was found that the FWS CW had the higher tendency to emit CH4 than the VF CW during four seasons of one year.

Xu, K.; Liu, C.; Ebie, Y.; Inamori, Y.

2008-12-01

35

Image Processing Techniques for Glaucoma Detection  

Microsoft Academic Search

\\u000a Glaucoma is a disease caused due to neurodegeneration of the optic nerve which leads to blindness. It can be evaluated by\\u000a monitoring intra ocular pressure (IOP), visual field and the optic disc appearance (cup-to-disc ratio). Glaucoma increases\\u000a the cup to disc ratio (CDR), affecting the peripheral vision loss. This paper addresses the various image processing techniques\\u000a to diagnose the glaucoma

Mishra Madhusudhan; Nath Malay; S. R. Nirmala; Dandapat Samerendra

36

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

37

Vertical Disintegration  

Microsoft Academic Search

With economies of scale, a vertically integrated firm can lower its upstream cost by supplying downstream competitors. The competitors may strategically choose not to purchase from the integrated firm, unless the latter's price for the intermediate good is sufficiently lower than those of alternative suppliers. In a simple model of dynamic scale economies through learning by doing, equilibrium vertical disintegration

Yongmin Chen

2005-01-01

38

THE VERTICAL  

NASA Technical Reports Server (NTRS)

'THE VERTICAL' computer keyboard is designed to address critical factors which contribute to Repetitive Motion Injuries (RMI) (including Carpal Tunnel Syndrome) in association with computer keyboard usage. This keyboard splits the standard QWERTY design into two halves and positions each half 90 degrees from the desk. In order to access a computer correctly. 'THE VERTICAL' requires users to position their bodies in optimal alignment with the keyboard. The orthopaedically neutral forearm position (with hands palms-in and thumbs-up) reduces nerve compression in the forearm. The vertically arranged keypad halves ameliorate onset occurrence of keyboard-associated RMI. By utilizing visually-reference mirrored mylar surfaces adjustable to the user's eye, the user is able to readily reference any key indicia (reversed) just as they would on a conventional keyboard. Transverse adjustability substantially reduces cumulative musculoskeletal discomfort in the shoulders. 'THE VERTICAL' eliminates the need for an exterior mouse by offering a convenient finger-accessible curser control while the hands remain in the vertically neutral position. The potential commercial application for 'THE VERTICAL' is enormous since the product can effect every person who uses a computer anywhere in the world. Employers and their insurance carriers are spending hundreds of millions of dollars per year as a result of RMI. This keyboard will reduce the risk.

Albert, Stephen L.; Spencer, Jeffrey B.

1994-01-01

39

Vertical mammaplasty.  

PubMed

Current criticisms regarding vertical mammaplasty include problems with poor immediate postoperative appearance, nipple-areola complex malposition, and excessive lower pole length. These problems can be avoided by proper patient selection, by utilizing correct concepts of skin design, and by observing correct glandular resection and closure concepts. Vertical mammaplasty also can result in other problems, such as hypertrophic circumareolar scars and lower pole deformities, including notching, boxy shape, infra-areolar depression, and flatness. These problems are also largely avoidable by using correct technique. Several basic concepts described previously have not proven necessary to achieve good results. Abandoning some of these principles has contributed to the ability to establish an aesthetically ideal breast shape intraoperatively as well as to a decrease in morbidity. This includes eliminating liposuction as a major integral component of the procedure, eliminating suturing the gland to the pectoralis muscle, not undermining the lower pole skin, and avoiding overly wide skin resection and tight wound closure that produces significant lower pole distortion in the early postoperative period. An important concept that has proven reliable is to use a "closed" design that does not predetermine the areolar opening whenever circumstances permit. When this is not possible, a modification that utilizes the smallest possible circumference as an open design is better than a large "mosque." These alternatives allow greater flexibility in determining final nipple position and also reduce the risk of hypertrophic circumareolar scars. Important glandular resection concepts include creating pillars that are attached to both the skin and the chest wall; making them of adequate dimension to avoid postoperative lower pole shape problems, such as flattening; resecting closer to the skin lateral to the pillars to avoid a boxy breast shape; and using a drain both to assist in accurately determining the endpoint of resection and to avoid postoperative seromas. Key closure concepts include approximation of the superior surfaces of the pillars at their base to maintain vertical height and thereby prevent lower pole flattening; approximation of the inferior surfaces of the pillars to the base of the breast to prevent notching; and proper management of the vertical incision by restricting the purse-string suture effect to only the inferior portion of the incision, where there may be skin excess present. Inclusion of these concepts leads to predictable and improved aesthetic results in vertical mammaplasty. This allows full realization of the purported advantages of vertical mammaplasty and allows this method to be utilized with a level of confidence similar to that seen with inverted-T techniques. PMID:15793463

Hidalgo, David A

2005-04-01

40

Vertical distribution of uranium concentrations and 235 U\\/ 238 U atom ratios in the coastal water off Aomori, Japan: A survey prior to the operation of a nuclear fuel reprocessing facility  

Microsoft Academic Search

Summary  From the viewpoint of environmental radioactivity monitoring, the determination of uranium and its isotope ratio is important\\u000a for identifying and assessing the environmental impact of any unexpected release from nuclear facilities. In this work, a\\u000a survey was conducted to determine 238U concentrations and 235U\\/238U atom ratios in coastal waters off Rokkasho Village, Aomori, Japan, where several uranium-related nuclear facilities have

J. Zheng; M. Yamada; T. Aono; M. Kusakabe

2006-01-01

41

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.

42

Validation of vertical velocities using in situ measurements  

Microsoft Academic Search

We use a conceptional backward trajectory approach to reconstruct water vapor and ozone mixing ratios in various diabatic or kinematic vertical velocity scenarios to validate vertical velocities in the upper TTL. Therefore, backward trajectories are initialized along the flight tracks of the tropical SCOUT-O3 campaign in Northern Australia\\/2005 and are calculated in either a diabatic or a kinematic vertical velocity

Felix Ploeger; Paul Konopka; Cornelius Schiller; Gebhard Günther; Jens-Uwe Grooss; Rolf Müller

2010-01-01

43

Bilateral ischemic optic neuropathy after transurethral prostatic resection: a case report  

Microsoft Academic Search

BACKGROUND: Nonarteritic ischemic optic neuropathy affects the anterior portion of the optic nerve and is characterized by sudden, painless visual loss. The affected eye has a relative afferent pupillary defect. The typical funduscopic appearance includes optic disc edema, with associated nerve fiber layer hemorrhage. Risk factors include advanced age, systemic hypertension, nocturnal hypotension, diabetes mellitus, and a small cup-to-disc ratio.

Luis M Sadaba; Alfredo Garcia-Layana; Miguel J Maldonado; Jose M Berian

2006-01-01

44

The Bristol Shared Care Glaucoma Study: reliability of community optometric and hospital eye service test measures  

Microsoft Academic Search

BACKGROUND\\/AIMSPrimary open angle glaucoma patients and glaucoma suspects make up a considerable proportion of outpatient ophthalmological attendances and require lifelong review. Community optometrists can be suitably trained for assessment of glaucoma. This randomised controlled trial aims to assess the ability of community optometrists in the monitoring of this group of patients.METHODSMeasures of cup to disc ratio, visual field score, and

P G D Spry; I C Spencer; J M Sparrow; T J Peters; S T Brookes; S Gray; I Baker; J E Furber; D L Easty

1999-01-01

45

Vertical bounce of two vertically aligned balls  

NASA Astrophysics Data System (ADS)

When a tennis ball rests on top of a basketball and both drop to the floor together, the tennis ball is projected vertically at high speed. A mass-spring model of the impact, as well as air track data, suggest that the tennis ball should be projected at relatively low speed. Measurements of the forces on each ball and the bounce of vertically aligned superballs are used to resolve the discrepancy.

Cross, Rod

2007-11-01

46

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

2011-03-08

47

Radius Ratio  

NSDL National Science Digital Library

This is a set of animations that demonstrates properties of the spherical holes formed when uniform spheres are packed. Cubic, octahedral and tetrahedral packing arrangements may be examined without anything in the holes,and with the repective holes filled. The sizes of the various holes relative to the spheres being packed are shown, which can lead students into an exploration of the radius ratio concept. An example is given of computing the relative size of an octahedral hole.

48

Vertical axis windmill  

SciTech Connect

A vertical axis windmill is described which involves a rotatable central vertical shaft having horizontal arms pivotally supporting three sails that are free to function in the wind like the main sail on a sail boat, and means for disabling the sails to allow the windmill to be stopped in a blowing wind.

Campbell, J.S.

1980-04-08

49

Vertical axis wind turbine  

Microsoft Academic Search

A Darrieus-type vertical axis wind turbine is disclosed which includes a vertically extending rotor tube mounted on a support structure with two or three rotor blades of troposkein configuration on the rotor tube for rotating the tube in response to wind energy and thereby drive a generator to produce electrical power. The turbine includes an erection hinge which permits assembly

Kutcher

1984-01-01

50

Vertical Line Test  

NSDL National Science Digital Library

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

2010-01-01

51

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

52

Paroxysmal Vertical Ocular Dyskinesia.  

National Technical Information Service (NTIS)

Paroxysmal vertical ocular dyskinesia of a previously undescribed nature is reported in a 42-year old woman with demyelinating disease, who was affected with a myelopathy, bilateral amblyopia, and a modified sylvian aqueduct syndrome. Electroencephalograp...

J. B. MacLean J. F. Sassin

1973-01-01

53

Verticality in hydroelectric machines  

SciTech Connect

Everyone who erects a vertical hydroelectric machine makes an effort to put the machine together so that its elements are vertical. A plumb line (or its optical equivalent) is a practical starting point for aligning the stationary parts of the machine - the generator stator, turbine case, and bearings. This does not mean, though, that the machine parts must be in near-perfect vertical orientation for the machine to perform well. Verticality is sometimes over-emphasized when procedures are undertaken to achieve good machine alignment. If the generator rotor, the connecting shaft, and the turbine runner are centered in stationary parts that are well-aligned along the same axis angle, this angle can depart from true vertical by a significant amount without ill effect. Mechanical balance does not often play a large part in determining how well a generator rotor is centered in the air gap. Magnetic forces are much more important. This is why it is desirable to maintain air gap variations around the machine to less than 5 percent from the average. However, this is sometimes difficult, especially if bearing clearances are large.

O'Kelly, F.

1991-12-01

54

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

55

Vertical breast reduction.  

PubMed

The vertical approach to breast reduction surgery has achieved increasing popularity. The learning curve can be a problem for surgeons starting to incorporate vertical techniques into their practices; the medial pedicle approach is outlined in detail. Designing and creating the medial pedicle is straightforward and rotating it into position is easy. An elegant curve to the lower pole of the reduced breast can thus be created. Current concepts related to the skin brassiere, breast sutures, and the longevity of results are reviewed. It is important for the surgeon to understand that the skin resection pattern and the pedicle design are separate issues when discussing breast reduction surgery. PMID:20574477

Hall-Findlay, Elizabeth J

2004-08-01

56

Vertical axis windmill  

SciTech Connect

A vertical axis windmill has a blade pivotally connected to a rotatable support structure on an axis passing through its center of gravity which is arranged to lie forward of its aerodynamic center whereby the blade automatically swings outwardly and inwardly when moving on the windward and leeward sides respectively of the axis of rotation of said support means.

Zheug, Y.K.

1984-03-06

57

Vertical shaft windmill  

SciTech Connect

A vertical shaft has several equally spaced blades mounted thereon. Each blade consists of an inboard section and an outboard section skew hinged to the inboard section. The inboard sections automatically adjust their positions with respect to the fixed inboard sections with changes in velocity of the wind. This windmill design automatically governs the maximum rotational speed of shaft.

Grana, D.C.; Inge, S.V. Jr.

1983-11-15

58

Vertical shaft windmill  

NASA Technical Reports Server (NTRS)

A vertical shaft has several equally spaced blades mounted. Each blade consists of an inboard section and an outboard section skew hinged to the inboard section. The inboard sections automatically adjust their positions with respect to the fixed inboard sections with changes in velocity of the wind. This windmill design automatically governs the maximum rotational speed of shaft.

Grana, D. C.; Inge, S. V., Jr. (inventors)

1983-01-01

59

Improved vertical scanning interferometry  

Microsoft Academic Search

Vertical scanning interferometers are routinely used for the measurement of optical fiber connectors. There are increasing needs for measurements of such items as machined surfaces, contact lenses, paint texture, cell structure, and integrated circuit devices, to name a few. These structures have too much depth, or are too rough, to measure with standard interferometry methods. Phase- measurement interferometry methods are

Akiko Harasaki; Joanna Schmidt; James C. Wyant

2000-01-01

60

Developing Vertical File Resources.  

ERIC Educational Resources Information Center

Describes how to develop vertical file resources for school libraries. Discusses the importance of having primary sources that are not available in other formats; sources for obtaining materials, including the Internet and printed sources; how to organize the materials; providing access; and promoting the collection. (LRW)

Smallwood, Carol

1998-01-01

61

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

62

Platinum ratio search versus golden ratio search  

Microsoft Academic Search

In this simulation study, we examine the traditional golden ratio search in view of cost minimization and search risk, and propose an alternative search plan with what we call “platinum ratio”. The golden ratio search has been thought the best for unimodal optimization. However, our study shows that the golden ratio search is the best only in the sense of

Xia Pan

2008-01-01

63

Vertical vector face lift.  

PubMed

Facial rejuvenation using local anesthesia has evolved in the past decade as a safer option for patients seeking fewer complications and minimal downtime. Mini- and short-scar face lifts using more conservative incision lengths and extent of undermining can be effective in the younger patient with lower face laxity and minimal loose, elastotic neck skin. By incorporating both an anterior and posterior approach and using an incision length between the mini and more traditional face lift, the Vertical Vector Face Lift can achieve longer-lasting and natural results with lesser cost and risk. Submentoplasty and liposuction of the neck and jawline, fundamental components of the vertical vector face lift, act synergistically with superficial musculoaponeurotic system plication to reestablish a more youthful, sculpted cervicomental angle, even in patients with prominent jowls. Dramatic results can be achieved in the right patient by combining with other procedures such as injectable fillers, chin implants, laser resurfacing, or upper and lower blepharoplasties. PMID:21276163

Somoano, Brian; Chan, Joanna; Morganroth, Greg

2011-01-01

64

Learning About Ratios  

NSDL National Science Digital Library

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

Hadley, Mrs.

2005-06-17

65

Association between Myopia and Glaucoma in the United States Population  

PubMed Central

Purpose. To investigate the association between myopia and the prevalence of glaucoma. Methods. This cross-sectional study included 5277 participants from the 2005 to 2008 National Health and Nutrition Examination Survey, greater than or equal to 40 years old, without history of cataract or refractive surgery, who underwent auto-refraction measurement. The predictor was refractive status; emmetropia (?0.99 to +0.99 diopters [D]), mild myopia (?1.00 to ?2.99 D), moderate myopia (?3.00 to ?5.99 D), severe myopia (> ?6.00 D), and hyperopia (> 1.00 D). The outcomes were self-reported glaucoma, vertical cup-to-disc ratio and visual field defects as found on frequency doubling technology (FDT) testing Results. Odds of self-reported glaucoma were not significantly increased in mild (odds ratio [OR] 0.90, confidence interval [CI] 0.56–1.45), moderate (OR 1.40, CI 0.62–3.16), or severe (OR 0.26, CI 0.08–0.80) myopes compared with emmetropes. Odds of vertical cup-to-disc ratio greater than or equal to 0.7 were not significantly increased in mild (OR 0.84, CI 0.31–2.25), moderate (OR 0.37, CI 0.04–3.57), or severe (OR 0.85, CI 0.09–8.42) myopes compared with emmetropes. Odds of any visual field defects were significantly increased in mild (OR 2.02, CI 1.28–3.19), moderate (OR 3.09, CI 1.42–6.72), and severe (OR 14.43, CI 5.13–40.61) myopes compared with emmetropes. The ?2 test indicated a significant difference (P = 0.001) in the distribution of subjects with each category of visual field status across subjects with each refractive status; the proportion of subjects with worse visual field defects increased with worsening myopia severity. Conclusions. The association between myopia and visual field defects may represent an increased risk of glaucoma among myopes, and the lack of association with self-reported glaucoma may suggest a need for greater glaucoma surveillance in this population.

Qiu, Mary; Wang, Sophia Y.; Singh, Kuldev; Lin, Shan C.

2013-01-01

66

Vertical blind assembly  

US Patent & Trademark Office Database

A vertical blind assembly includes an elongate header casing and two sets of louvers movably supported in adjacent channels within the header casing, including a first set of plain louvers structured to be moved horizontally along the length of the first channel, and a second set of louvers which are molded and configured in a decorative, three-dimensional pattern and structured to be moved horizontally along the length of the second channel so that they are positioned in front of the first set of louvers.

1997-01-28

67

'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

68

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.

69

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

70

Natural convection in vertical Bridgman configurations  

NASA Astrophysics Data System (ADS)

Buoyancy driven convection in closed vertical cylinders heated from below and crystal growth in corresponding configurations (vertical Bridgman technique with top seeding) have been studied experimentally and theoretically. The hydrodynamic state in such configurations is described by three dimensionless numbers, the Rayleigh number Ra, the aspect ratio (height h/diameter d) and the Prandtl number Pr. Two different types of melts have been investigated, H 2O (Pr = 6.7), and Ga and GaSb melts (Pr ? 2 × 10 -2) for various aspect ratios (0.5 ? h/ d ? 5) and Rayleigh numbers up to 10 8. Both experimental results and numerical analysis for the onset of convection (critical Rayleigh number Ra c1) and the state of convective flow are presented. The values of Ra c1 for 0.5 ? h/ d ? 5 and the symmetries of the basic flow (axial symmetry for h/ d = 0.5 and non-axial symmetry for 1 ? h/ d ? 5) are in good agreement with the theoretical predictions of Charlson and Sani [1]. Te-doped GaSb crystals have been grown by using the vertical Bridgman technique with top seeding. Temperatures have been measured in the GaSb melt during growth and compared with the results of our flow investigations in Ga melts. It shows clearly, that the occurrence of doping striations in the GaSb crystals can be very well correlated to the unsteady flow regimes.

Müller, G.; Neumann, G.; Weber, W.

1984-12-01

71

Consistent vertical and horizontal resolution. [for internal gravity waves study  

NASA Technical Reports Server (NTRS)

Simple physical relations (namely, the Rossby ratio between vertical and horizontal scales in quasi-geostrophic flow and the dispersion relation for internal gravity waves) are used to estimate the vertical resolution consistent with a given horizontal resolution. Using these relations it is found that virtually all large scale models and observing systems have inadequate vertical resolution. In models, the excess horizontal resolution can lead to increased model 'noise' rather than improved accuracy. In observing systems, the finer horizontal scales can be severely misrepresented.

Lindzen, Richard S.; Fox-Rabinovitz, Michael

1989-01-01

72

Vertically integrated silicon-germanium nanowire field-effect transistor  

NASA Astrophysics Data System (ADS)

We demonstrate in this paper the possibility to vertically integrate SiGe nanowires in order to use them as vertical channel for field-effect transistors (FETs). We report a threshold voltage close to 3.9 V, an ION/IOFF ratio of 104. The subthreshold slope was estimated to be around 0.9 V/decade and explained by a high traps density at the nanowire core/oxide shell interface with an estimated density of interface traps Dit ~ 1.2 × 1013 cm-2 eV-1. Comparisons are made with both vertical Si and horizontal SiGe FETs performances.

Rosaz, G.; Salem, B.; Pauc, N.; Potié, A.; Gentile, P.; Baron, T.

2011-11-01

73

A New and Efficient Method for Automatic Optic Disc Detection Using Geometrical Features  

Microsoft Academic Search

\\u000a Automatic optic disc (OD) detection is a key processing step in algorithms aiming for automatic extraction of retinal vascular\\u000a abnormalities for diagnosing cardiovascular diseases and cup-to-disc ratio assessment for diagnosing glaucoma. In this paper,\\u000a we propose a new method for automatic OD segmentation and center computation. The proposed method automatically determines\\u000a the threshold intensity value by utilizing OD area information

Alauddin Bhuiyan; Ryo Kawasaki; Tien Yin Wong; Rao Kotagiri

74

The Golden Ratio  

NSDL National Science Digital Library

In this lesson, "students learn about ratios, including the 'Golden Ratio', a ratio of length to width that can be found in art, architecture, and nature. Students examine different ratios to determine whether the Golden Ratio can be found in the human body." (from NCTM's Illuminations) This is lesson 3 in a 7-lesson unit called "Measuring Up"

Mathematics, Illuminations N.

2009-02-18

75

Laser drilling of vertical vias in silicon  

SciTech Connect

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

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

1993-08-01

76

Vertical turbulent diffusion in stably stratified flows  

NASA Astrophysics Data System (ADS)

Based on a Lagrangian description of fluid particle dispersion we suggest that there is a single expression for the vertical eddy diffusivity for all scalars following fluid particles in stably stratified flows. This expression is the same as the Osborn-Cox diffusivity for buoyancy. To test this hypothesis we carry out turbulence simulations with stable background stratification by solving the Boussinesq equations with random forcing together with the equation for a passive scalar with an initial vertical Gauss profile. The development of the mean scalar concentration is studied for three different values of the width of the profile, ?. It is found that the passive scalar diffuses in very good agreement with the classical diffusion equation if the ratio between ? and a turbulent length scale is large enough. The associated eddy diffusivity agrees exactly with the Osborn-Cox diffusivity for buoyancy.

Lindborg, Erik; Fedina, Ekaterina

2009-01-01

77

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

78

Vertical Dimension in Complete Dentures.  

National Technical Information Service (NTIS)

The video demonstrates proportional and functional methods to establish a tentative vertical dimension for the edentulous patient. It emphasizes the correlation of this dimension with the centric relation.

1994-01-01

79

Vertical quantum dot with a vertically coupled charge detector  

Microsoft Academic Search

We fabricated a vertical quantum dot equipped with a charge detector. The dot current flows vertically between the top and bottom contacts. The charge detector is formed at the bottom contact layer with a current channel constricted to the region just under the dot. This channel current is reduced by addition of an extra electron onto the dot due to

Koichiro Zaitsu; Yosuke Kitamura; Keiji Ono; Seigo Tarucha

2008-01-01

80

Flow effects in a vertical CVD reactor  

NASA Technical Reports Server (NTRS)

A model is presented to simulate the non-Boussinesq flow in a vertical, two-dimensional, chemical vapor deposition reactor under atmospheric pressure. Temperature-dependent conductivity, mass diffusivity, viscosity models, and reactive species mass transfer to the substrate are incorporated. In the limits of small Mach number and small aspect ratio, asymptotic expressions for the flow, temperature, and species fields are developed. Soret diffusion effects are also investigated. Analytical solutions predict an inverse relationship between temperature field and concentration field due to Soret effects. This finding is consistent with numerical simulations, assisting in the understanding of the complex interactions amongst the flow, thermal, and species fields in a chemically reacting system.

Young, G. W.; Hariharan, S. I.; Carnahan, R.

1992-01-01

81

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

82

Vertical strabismus in monofixation syndrome  

Microsoft Academic Search

Purpose: The manifest angle of the horizontal deviation in monofixation syndrome (MFS) has been reported to reach a maximum of 8 to 10 PD. Review of the literature, however, revealed no studies about the vertical deviation associated with MFS. The purpose of this study is to evaluate the range of the angle of the vertical deviation in MFS. Methods: Forty

Dong Gyu Choi; Sherwin J. Isenberg

2001-01-01

83

Functions and Vertical Line Test  

NSDL National Science Digital Library

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

2010-01-01

84

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

85

Vertical quantum dot with a vertically coupled charge detector  

NASA Astrophysics Data System (ADS)

We fabricated a vertical quantum dot equipped with a charge detector. The dot current flows vertically between the top and bottom contacts. The charge detector is formed at the bottom contact layer with a current channel constricted to the region just under the dot. This channel current is reduced by addition of an extra electron onto the dot due to the electrostatic coupling to the dot. The charge state of the vertical dot was detected, starting from zero electrons. The sensitivity of the charge detector was comparable to that previously reported for lateral dots with nearby quantum point contacts.

Zaitsu, Koichiro; Kitamura, Yosuke; Ono, Keiji; Tarucha, Seigo

2008-01-01

86

Optimal design for energy conservation of a vertically articulated manipulator  

Microsoft Academic Search

In order to help reduce global warming, it is important to design even for a vertically articulated manipulator with 3 joints so that the dissipated energy of running gears with motor can be minimized. This paper proposes an optimal design method for simultaneously determining 8 design variables, which are the 3 motor masses, the 3 reduction gear ratios, the counterbalancer

Teruyuki Izumi; Miku Adachi; Hai Zhou

2007-01-01

87

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

88

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

89

On the characterization of noninteger vertices of the relaxation polyhedron in the multi-index axial assignment problem  

NASA Astrophysics Data System (ADS)

Theorems about the characterization and exponential growth of the denominators of fractional components of noninteger vertices of the relaxation polyhedron in the multi-index axial assignment problem are proved. They made it possible to obtain new lower bounds on the number of noninteger vertices of this polyhedron and to refute the conjecture on the estimate of the ratio of the number of integer vertices to the number of all vertices of the multi-index axial transportation polyhedron determined by integer vectors.

Kravtsov, V. M.

2010-09-01

90

Horizontal and Vertical Line Designs.  

ERIC Educational Resources Information Center

Presents an art lesson in which students learn about the artist Piet Mondrian and create their own abstract artworks. Focuses on geometric shapes using horizontal and vertical lines. Includes background information about the artist. (CMK)

Johns, Pat

2003-01-01

91

Vertical Electromagnetic Pulse (VEMP) Testing.  

National Technical Information Service (NTIS)

This TOP provides methods for planning, providing instrumentation, and execution of testing of Army/DOD Materiel to determine the effects of Vertical Component High Altitude Electromagnetic Pulse (VHEMP) Environment on the safety and/or reliability of the...

2009-01-01

92

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

93

Vertical Reactor Coolant Pump Instabilities.  

National Technical Information Service (NTIS)

This paper describes the investigation conducted at the Tennessee Valley Authority's Sequoyah Nuclear Power Plant to determine and correct increasing vibrations in the vertical reactor coolant pumps. Diagnostic procedures to determine the vibration causes...

1985-01-01

94

Horizontal Inequity and Vertical Redistribution  

Microsoft Academic Search

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

Peter J. Lambert; Xavier Ramos

1997-01-01

95

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.

96

Enhanced UV-assisted vertical etching of polyethylene terephthalate for fabrication of microsystems  

Microsoft Academic Search

The improved ultraviolet (UV)-assisted vertical etching of polyethylene terephthalate (PET) for manufacturing microsystem components is reported. The PET vertical etching is achieved by using a dimethylformamide solution assisted by ultraviolet illumination onto a patterned PET substrate. The process is carried out in low temperature solutions for the benefits of low shrinkage and deformation of PET, yet having high aspect ratio

A. Jahanshahi; H. Pajouhi; A. H. Tamaddon; A. Sadeghi; S. Mohajerzadeh; B. Khadem-Hoseiny

2009-01-01

97

Energy efficient wireless link monitoring using probability inequality for vertical handover  

Microsoft Academic Search

This paper proposes a new way of measuring signal to interference and noise ratio (SINR) at a low level of power consumption for vertical handover. In order to select the most suitable radio access networks (RAN) in vertical handover, the SINR of the alternative RAN should be measured at a certain interval while communicating with the existing RAN. In our

Yuji Ikeda; Kosuke Yamazaki; Issei Kanno; Yasuhiko Hiehata; Hiroyasu Ishikawa

2010-01-01

98

Maximum ratio transmission  

Microsoft Academic Search

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

Titus K. Y. Lo

1999-01-01

99

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

100

Likelihood Ratio Tests  

NSDL National Science Digital Library

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

Siegrist, Kyle

2009-01-12

101

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

102

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

103

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

104

Investigation of Factors Affecting Vertical Drain Behavior  

Microsoft Academic Search

Some influencing factors on vertical drain behavior were investigated by laboratory tests as well as by back-analyses of test embankments on vertical drain improved subsoil at Saga Airport, Saga, Japan. Based on the results from this study, suggestions are made on determining the design parameters for vertical drain improvement. For the discharge capacity test of a prefabricated vertical drain, confining

Jun-Chun Chai; Norihiko Miura

1999-01-01

105

The Small Tight Aspect Ratio Tokamak experiment  

SciTech Connect

Low-aspect-ratio tokamaks offer both the economic advantage of smaller size and a number of physics advantages which are not available at conventional aspect ratio. The Small Tight Aspect Ratio Tokamak (START) [[ital Fusion] [ital Technology] 1990, edited by B. E. Keen, M. Huguet, and R. Hemsworth (North-Holland, Amsterdam, 1991), Vol. 1, p. 353] was conceived as a first substantial test of tokamak plasma behavior at low aspect ratio. It has achieved plasma currents up to 200 kA, peak densities of [similar to]2[times]10[sup 20] m[sup [minus]3] and central electron temperatures of [similar to]500 eV at an aspect ratio of 1.3--1.5. Central beta values of [similar to]13% have been measured and the volume-averaged beta [l angle][beta][r angle] can approach the Troyon limit. Plasmas are naturally elongated ([kappa][approx lt]2.0) and are vertically stable without feedback control. Major disruptions have not been observed at low aspect ratios ([ital A][le]2.0).

Colchin, R.J.; Carolan, P.G.; Duck, R.; Edlington, T.; Erents, S.K.; Ferreira, J.; Fielding, S.J.; Gibson, K.; Goodall, D.H.J.; Gryaznevich, M.; Hender, T.C.; Hugill, J.; Jenkins, I.; Li, J.; Manhood, S.J.; Parham, B.J.; Robinson, D.C.; Singleton, M.; Sykes, A.; Todd, T.N.; Turner, M.F.; Valovic, M.; Walsh, M.; Wilson, H.R. (AEA Fusion Technology, Culham Laboratory (EURATOM/UKAEA Association), Abingdon, Oxon (United Kingdom))

1993-07-01

106

Scale Shrinkage in Vertical Equating  

Microsoft Academic Search

As an alternative to equipercentile equating in the area of multilevel achievement test batteries, item response theory (IRT) vertical equating has produced unexpected results. When expanded standard scores were obtained to link the Comprehensive Test of Basic Skills and the California Achievement Test, the variance of test scores diminished both within particular grade levels from fall to spring, and also

Gregory Camilli; Kentaro Yamamoto; Ming-mei Wang

1993-01-01

107

Vertically Fused Face Sheet Performance.  

National Technical Information Service (NTIS)

This study evaluates the performance of vertically fused face sheet mirrors used in adaptive optical systems that are subjected to high thermal irradiance. A one meter diameter by 20mm thick segmented, low expansion glass face sheet was fabricated from di...

H. M. Simmons J. W. Pepi

1982-01-01

108

Graphs with four boundary vertices  

Microsoft Academic Search

A vertex v of a graph G is a boundary vertex if there exists a vertex u such that the distance in G from u to v is at least the distance from u to any neighbour of v. We give a full description of all graphs that have exactly four boundary vertices, which answers a question of Hasegawa and

Tobias Müller; A. Por; J.-S. Sereni

2011-01-01

109

Vertical Instability in KEK Booster  

Microsoft Academic Search

In the KEK Booster Synchrotron, from one msec after injection to extraction timing, beam intensity is stable, though it is reduced to about one half during one msec after injection. An instability of the vertical direction is one of the candidates of the beam loss. The e-folding time of the instability is less than 0.1 msec, and it strongly depends

M. Suetake; T. Kasuga; T. Kawakubo; I. Sakai; H. Someya; S. Takeda

1983-01-01

110

Vertical Pricing and Parallel Imports  

Microsoft Academic Search

We generalize an earlier model of international vertical pricing to explain key features of parallel imports, or unauthorized trade in legitimate goods. When a manufacturer (or trademark owner) sells its product through an independent agent in one country, the agent may find it profitable to engage in parallel trade, selling the product to another country without the authorization of the

Yongmin Chen; KEITH E. MASKUS

2005-01-01

111

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

112

Directional Gear Ratio Transmission.  

National Technical Information Service (NTIS)

Epicyclic gear transmissions which transmit output at a gear ratio dependent only upon the input's direction are considered. A transmission housing envelops two epicyclic gear assemblies, and has shafts extending from it. One shaft is attached to a sun ge...

A. E. Lefever

1982-01-01

113

Inelastic Ratio of ARALL.  

National Technical Information Service (NTIS)

The inelastic ratio (IR) of ARALL was determined in bending tests on four configurations with varying length, width, thickness, fiber orientation, and number of layers. The IR is 65%, differences between the configurations are negligibly small. The small ...

M. L. C. E. Verbruggen

1984-01-01

114

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

115

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

116

Caesium contamination and vertical distribution in undisturbed soils in Croatia  

Microsoft Academic Search

The deposition and vertical distribution of 137Cs and 134Cs in the first 25cm of undisturbed soil profiles were studied at more than 50 locations in Croatia. Relative contributions of fallout from weapon-testing and the Chernobyl accident-derived fallout to the total 137Cs deposition were estimated on the basis of the 137Cs\\/134Cs activity ratio. Total weapon-testing-derived deposition can be generally treated as

D. Bariši?; A. Verta?nik; S. Luli?

1999-01-01

117

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

118

Dissolution of a Carbon Dioxide Bubble in a Vertical Pipe  

Microsoft Academic Search

Dissolution of single carbon dioxide (CO2) bubbles in a vertical pipe of 25 mm diameter is measured to examine the effects of the ratio lambda of the sphere-volume equivalent bubble diameter to the pipe diameter, the liquid Reynolds number and surfactants on mass transfer. The bubble diameter and liquid Reynolds number are varied from 5.0 to 26 mm (0.20 <

Satoru Abe; Hideaki Okawa; Shigeo Hosokawa; Akio Tomiyama

2008-01-01

119

Vertical formations demand unique treatments  

SciTech Connect

In the US midcontinent area, major thrust faults trap large quantities of hydrocarbons in the down-thrown fault block. As exploration of these thrust fault structures continues, the application of extended reach and horizontal well bores will increase. Formations in deep structures are apt to have lower porosity and permeability than the currently developed thrust faults and thus, require fracture stimulation. In addition, the portion of the formation closest to the fault may be subjected to folding resulting in a vertical formation penetrated by a horizontal well bore. Low porosity and vertical bedding were encountered in the City of Lawton No. 1-34, an 18,088-ft wildcat (14,627-ft TVD) in Caddo County, Oklahoma. This article details methods to overcome the obstacles that well bore and formation geometry present to fracture stimulation operations in the 17,714-ft (14,614-ft TVD) Britt sand.

Fairchild, K. [Fina Oil and Chemical Co., Midland, TX (United States)

1996-04-01

120

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

121

Automated Assessment of the Optic Nerve Head on Stereo Disc Photographs  

PubMed Central

Purpose To develop automated software for optic nerve head (ONH) quantitative assessment from stereoscopic disc photographs and to evaluate its performance in comparison with human expert assessment. Methods A fully automated system, including three-dimensional ONH modeling, disc margin detection, cup margin detection, and calculation of stereometric ONH parameters, was developed and tested. One eye each from 54 subjects (23 healthy, 17 suspected glaucoma, and 14 glaucoma) was enrolled. The majority opinion of three experts defined disc and cup margins on the disc photographs was used for comparison. Seven ONH parameters, disc area, rim area, rim volume, cup area, cup volume, cup-to-disc (C/D) area ratio, and vertical C/D ratio, were computed based on both machine- and expert-defined margins and compared between the methods. Results All automated ONH measurements showed good correlation with the expert defined margins (Pearson r = 0.90, disc area; 0.56, rim area; 0.78, rim volume; 0.88, cup area; 0.93, cup volume; 0.69, C/D area ratio; and 0.67, vertical C/D ratio; all P ? 0.0001). No statistically significant difference was found in the glaucoma-discriminating ability of all seven ONH parameters (P ? 0.21). The mean or median of automatically defined disc and cup areas was significantly higher than the subjective assessment (disc area P = 0.0001, t-test; cup area P = 0.036, Wilcoxon signed ranks test), although they had high correlation coefficients. The software failed to detect the disc margin for all the disc photographs with peripapillary atrophy. Conclusions The automated ONH analysis method provides an objective and quantitative ONH evaluation using widely available stereo disc photographs.

Xu, Juan; Ishikawa, Hiroshi; Wollstein, Gadi; Bilonick, Richard A.; Sung, Kyung R.; Kagemann, Larry; Townsend, Kelly A.; Schuman, Joel S.

2010-01-01

122

The latitudinal and vertical distribution of molecular hydrogen in the troposphere  

Microsoft Academic Search

Meridional profiles of the H. mixing ratio in surface air were obtained by continuous registrations during a ship cruise from Hamburg, West Germany, to Santo Domingo, Dominican Republic, in 1973. Vertical and meridional profiles in the troposphere were measured during a research flight from Cologne, West Germany, to Punta Arenas, Chile, in 1974. The average H. mixing ratio of surface

U. Schmidt; Atmosphiirische Chemie

1978-01-01

123

Results of examination of unsteady convection of vertical thermally unstable Bi-Sb-Te melts  

Microsoft Academic Search

Using a vertical destabilizing crystal growth arrangement, the characterization of the hydrodynamic behavior of Bi-Sb-Te alloys is obtained under the form of a dependency of the critical Rayleigh number on the melt geometry ratio. Low temperature gradients and greater geometry ratios direct to a greater hydrodynamic stability and allow microinhomogeneities to be avoided under the form of growth striations.

R. Kuhl; F. Koenig; R. Roestel

1990-01-01

124

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.

125

NASA-Ames vertical gun  

NASA Technical Reports Server (NTRS)

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

Schultz, P. H.

1984-01-01

126

Understanding basics of vertical pumps  

SciTech Connect

Discusses requirements of vertical centrifugal pumps for slurry service. Points out that the most commonly accepted criterion for the classification of a pump for a slurry application is wear adjustment. Presents graph showing the relative effect of radial thrust at other than best efficiency conditions. Diagram illustrates how radial thrust problems can be reduced by using a double volute. Examines the use of alloys, protective coatings (e.g. rubber or synthetic elastomers), and cast ceramics for corrosion and abrasion resistance.

Haentjens, W.D.

1983-01-20

127

The Golden Ratio  

NSDL National Science Digital Library

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

Narain, David L.

2001-01-01

128

5-Foot Vertical Wind Tunnel  

NASA Technical Reports Server (NTRS)

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

1930-01-01

129

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.

130

A Recipe for Ratio  

ERIC Educational Resources Information Center

Many learners still struggled to appreciate, and understand the difference between, the concepts of fractions and ratio. This is not just a UK phenomenon, which is demonstrated here by the use of a resource developed by the Wisconsin Centre for Education, in association with the Freudenthal Institute of the University of Utrecht, with a group of…

Moffett, Pamela

2012-01-01

131

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

132

Internally baffled, horizontal flow, vertical oil skimmer  

SciTech Connect

An internally baffled, horizontal flow, vertical oil separator or skimmer for the flotation and removal of oil from mixtures of oil and water has internal baffles that compel horizontal flow of a vertically elongated cross-section of fluid in the vertical vessel. The skimmer is of particular utility on offshore platforms where deck space is extremely expensive and limited.

Warne, J.P.

1981-12-29

133

Vertical partitioning algorithms for database design  

Microsoft Academic Search

This paper addresses the vertical partitioning of a set of logical records or a relation into fragments. The rationale behind vertical partitioning is to produce fragments, groups of attribute columns, that “closely match” the requirements of transactions.Vertical partitioning is applied in three contexts: a database stored on devices of a single type, a database stored in different memory levels, and

Shamkant B. Navathe; Stefano Ceri; Gio Wiederhold; Jinglie Dou

1984-01-01

134

On Vertical Mergers and Their Competitive Effects  

Microsoft Academic Search

It is well known that vertical integration cats change the pricing incentive of an upstream producer. However, it has not been noticed that vertical integration may also change the pricing incentive of downstream producer and the incentive of a competitor in choosing input suppliers. I develop an equilibrium theory of vertical merger that incorporates these additional strategic considerations. Under fairly

Yongmin Chen

2001-01-01

135

Vertical Lift - Not Just For Terrestrial Flight  

NASA Technical Reports Server (NTRS)

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

Young, Larry A

2000-01-01

136

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

137

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

138

PROPORTIONS and RATIOS  

NSDL National Science Digital Library

Using what you already know and the text, can you solve these problems? Just by looking at the titles below, describe in your journal what you think each activity is going to be about and how it relates to proportions and ratios. Which tastes juicier? Statue of Liberty : is the Statue of Liberty's nose too long? Describe in your journal how your favorite question above was answered. Also, include any fun facts you learned along the way. What ...

Squire, Mrs.

2009-04-13

139

Ratio Word Problems  

NSDL National Science Digital Library

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

2006-01-01

140

The Golden Ratio Encoder  

Microsoft Academic Search

This paper proposes a novel Nyquist-rate analog-to-digital (A\\/D) conversion algorithm which achieves exponential accuracy in the bit-rate despite using imperfe ct components. The proposed algorithm is based on a robust implementation of a beta-encoder with ? = ? = (1 + ? 5)\\/2, the golden ratio. It was previously shown that beta-encoders can be implemented in such a way that

Ingrid Daubechies; C. Sinan Güntürk; Yang Wang; Özgür Yilmaz

2008-01-01

141

Thinking Blocks: Ratios  

NSDL National Science Digital Library

This set of six interactive Flash activities gives students an opportunity to visually model and calculate the unknown quantity from ratios and other information, all in the context of solving word problems. A video demonstration introduces each method, and then students work on modeling and solving five problems. Students can check their modeling of the problem at intermediate stages. Teachers can track a student's progress throughout the problem set.

2012-01-01

142

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

143

Integration of Twenty-Bladed Cross-Flow Fan into Vertical Take-Off and Landing Aircraft.  

National Technical Information Service (NTIS)

The research presented is dedicated to determining an efficient rotor and housing system that will generate a sufficient thrust-to-weight ratio for vertical take-off and landing through computational modeling, implementation and experimentation. To accomp...

A. M. Jones

2013-01-01

144

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

145

Bound on vertical heat transport at large Prandtl number  

NASA Astrophysics Data System (ADS)

We prove a new upper bound on the vertical heat transport in Rayleigh-Bénard convection of the form c Ra( under the assumption that the ratio of Prandtl number over Rayleigh number satisfies {Pr}/{Ra}?c0 where the non-dimensional constant c0 depends on the aspect ratio of the domain only. This new rigorous bound agrees with the (optimal) Ra bound (modulo logarithmic correction) on vertical heat transport for the infinite Prandtl number model for convection due to Constantin and Doering [P. Constantin, C.R. Doering, Infinite Prandtl number convection, J. Stat. Phys. 94 (1) (1999) 159-172] and Doering, Otto and Reznikoff [C.R. Doering, F. Otto, M.G. Reznikoff, Bounds on vertical heat transport for infinite Prandtl number Rayleigh-Bénard convection, J. Fluid Mech. 560 (2006) 229-241]. It also improves a uniform (in Prandtl number) Ra bound for the Nusselt number [P. Constantin, C.R. Doering, Heat transfer in convective turbulence, Nonlinearity 9 (1996) 1049-1060] in the case of large Prandtl number.

Wang, Xiaoming

2008-05-01

146

Vertical elliptical coronas caused by pollen.  

PubMed

Near-forward scattering by cloud droplets is known to give rise to colored rings, centered on the Sun or the Moon, which are called the corona. Because of the spherical shape of the droplets, the corona can be circular. A Finnish amateur astronomers' network has found a corona, in a seemingly cloudless sky, with a regular vertically elliptical shape. The aspect ratio of these ellipses changes with the altitude of the Sun or the Moon. Some brightening in the coronas has also been reported. Because of observations of high pollen concentrations at the time of occurrence of these coronas, we propose that some coronas can be explained as a result of scatteringbybirch pollen grains, which are more or less spheroidal. To explain other observed coronas, pollen grains with more complicated shapes, such as pine and spruce pollen grains, must be invoked. Our analysis is limited to spheroidal grains, for which the Fraunhofer theory gives analytical expressions of simple form. The more complicated shapes require numerical simulations or laboratory experiments, which we have not done. PMID:20935822

Parviainen, P; Bohren, C F; Mäkelä, V

1994-07-20

147

Distance cues for vertical vergence adaptation.  

PubMed

Vertical vergence can be trained to respond to vertical and/or horizontal conjugate eye position, horizontal vergence, and vertical head tilt. This cross-coupling is manifest as a vertical phoria aftereffect (monocular vertical vergence response) that varies with direction and distance of gaze. The function of the spatially dependent adaptation is to maintain the calibration between vertical eye alignment and intended placement of the two retinal images. Oculomotor adaptation stabilizes our sense of spatial localization and calibrates a body-referenced coordinate representation of visual space that is necessary for visually guided motor responses. We have tested the possible association of vertical phoria adaptation with perceptual cues to distance in the absence of any other associated motor activity. During adaptive training, vertical disparity vergence was associated with variations of perceptual distance cues (including loom, overlap, relative size, and relative motion), oculomotor distance cues (horizontal vergence), or a combination of both classes of cues. We observed that in a 2-h period the open-loop (monocular) vertical vergence response could not be trained to occur as an aftereffect in association with the perceptual cues to distance, whereas it could be trained in association with oculomotor cues. We conclude that the spatial specificity of vertical vergence aftereffects caused by short-term adaptation results from an associated cross-coupling with supranuclear sources of oculomotor activity. PMID:8539011

Schor, C M; McCandless, J W

1995-07-01

148

Vertical graphene-base hot-electron transistor.  

PubMed

We demonstrate vertical graphene-base hot-electron transistors (GB-HETs) with a variety of structures and material parameters. Our GB-HETs exhibit a current saturation with a high current on-off ratio (>10(5)), which results from both the vertical transport of hot electrons across the ultrathin graphene base and the filtering of hot electrons through a built-in energy barrier. The influences of the materials and their thicknesses used for the tunneling and filtering barriers on the common-base current gain ? are studied. The optimization of the SiO2 thickness and using HfO2 as the filtering barrier significantly improves the common-base current gain ? by more than 2 orders of magnitude. The results demonstrate that GB-HETs have a great potential for high-frequency, high-speed, and high-density integrated circuits. PMID:23668939

Zeng, Caifu; Song, Emil B; Wang, Minsheng; Lee, Sejoon; Torres, Carlos M; Tang, Jianshi; Weiller, Bruce H; Wang, Kang L

2013-06-12

149

Vertical array receptions of the Heard Island transmissions  

SciTech Connect

A long, vertical line array was deployed off Monterey, California during the Heard Island Feasibility Test to measure the modal content of the received signals. The array contained 32, equally spaced hydrophones spanning from 345 to 1740-m depth. The multichannel data were recorded through a tether to the R/V POINT SUR. The measurements had very low signal to noise ratios and indicated the cw transmission losses were approximately 140 dB for a source/receiver range of 17 000 km. Modal content was analyzed using (i) the modal extent versus depth, (ii) frequency-vertical wave-number spectra, (iii) modal beamforming and (iv) least squares fitting. All led to the conclusion that the modal population is surprisingly rich. There was strong evidence of population up to at least mode seven in the data.

Baggeroer, A.B.; Sperry, B. (Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)); Lashkari, K. (Monterey Bay Aquarium Research Institute, Monterey, California 93943 (United States)); Chiu, C.; Miller, J.H. (Naval Postgraduate School, Monterey, California 93943 (United States)); Mikhalevsky, P.N. (Science Applications International Corporation, McLean, Virginia 22102 (United States)); von der Heydt, K. (Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 (United States))

1994-10-01

150

Natural convection between a vertical cylinder and a surrounding array  

SciTech Connect

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

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

1992-01-01

151

Natural convection between a vertical cylinder and a surrounding array  

SciTech Connect

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

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

1992-09-01

152

Vertical structuring of gigantic jets  

NASA Astrophysics Data System (ADS)

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

Silva, Caitano L.; Pasko, Victor P.

2013-06-01

153

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

154

Galactic Spiral Shocks with Thermal Instability in Vertically Stratified Disks  

NASA Astrophysics Data System (ADS)

Galactic spiral shocks are dominant morphological features and believed to be responsible for substructure formation of spiral arms in disk galaxies. They can also provide a large amount of kinetic energy for the interstellar gas by tapping the rotational energy. We use numerical hydrodynamic simulations to investigate dynamics and structure of spiral shocks with thermal instability in vertically stratified galactic disks. We initially consider an isothermal disk in vertical hydrostatic equilibrium and let it evolve under interstellar cooling and heating. Due to cooling and heating, the disk rapidly turns to a dense slab near the midplane surrounded by rarefied gas at high-altitude regions. The imposed stellar spiral potential develops a vertically curved shock that exhibits strong flapping motions along the direction perpendicular to the arm. The flows across the spiral shock are characterized by transitions from rarefied to dense phases at the shock and from dense to rarefied phases at the postshock expansion zone. The shock flapping motions stirs the disk, supplying the gas with random kinetic energy. For a model resembling the galactic disk near the solar neighborhood, the density-weighted vertical velocity dispersions are 2 km/s for the rarefied gas and 1 km/s for the dense gas. The shock compression in this model reduces an amount of the rarefied gas from 29% to 19% by mass. Despite the flapping motions, the time-averaged profiles of surface density are similar to those of the one-dimensional counterparts, and the vertical density distribution is overall consistent with effective hydrostatic equilibrium. When self-gravity is included, the shock compression forms large gravitationally bound condensations with virial ratio of about 2 and typical masses of 0.5 to one million solar masses, comparable to the Jeans mass.

Kim, Chang-Goo; Kim, W.; Ostriker, E. C.

2010-01-01

155

Vertical profiles of the O2/N2 ratio in the stratosphere over Japan and Antarctica  

NASA Astrophysics Data System (ADS)

To examine the spatial and temporal behavior of stratospheric O2, air samples were collected using a cryogenic sampler over Sanriku, Japan and Syowa, Antarctica and analyzed for ?(O2/N2), ?15N of N2 and ?18O of O2. The measured values of all these components decreased gradually with height. The differences in ?(O2/N2), ?15N and ?18O between the middle and lowermost levels of the stratosphere were about 250, 100, and 180 per meg, respectively. The observed stratospheric profiles of ?15N and ?18O were in agreement with those calculated using a steady-state 1-dimensional eddy-diffusion/molecular-diffusion model, which suggests that the upward decrease of stratospheric ?(O2/N2) is caused by a gravitational separation of O2 and N2 molecules. The averaged stratospheric ?(O2/N2) at heights above 20-25 km over Sanriku, corrected for the gravitational separation, was always higher than the upper tropospheric ?(O2/N2) value over Japan, and it decreased secularly. From the past temporal ?(O2/N2) variation deduced from the gravitational separation-corrected stratospheric ?(O2/N2) values and the mean ages of the respective air samples, which corresponds to its secular trend in the troposphere, average terrestrial biospheric and oceanic CO2 uptake for October 1993-September 2001 were estimated to be 1.1 +/- 1.3 and 1.8 +/- 1.3 GtC yr-1, respectively.

Ishidoya, Shigeyuki; Sugawara, Satoshi; Hashida, Gen; Morimoto, Shinji; Aoki, Shuji; Nakazawa, Takakiyo; Yamanouchi, Takashi

2006-07-01

156

[Occlusal vertical dimension in removable complete dentures].  

PubMed

In removable complete dentures, the occlusal vertical dimension is an important factor for patients' satisfaction with aesthetics. An excessively reduced occlusal vertical dimension is especially likely to lead to complaints about aesthetics, whereas an increased occlusal vertical dimension may lead to discomfort and a decision not to wear the complete dentures. There are various methods for determining the occlusal vertical dimension in complete dentures, based on the vertical dimension in the rest position of the mandible or on phonetics. However, none of the methods have proven to be clearly superior, in terms of reliability, than the others. The assessment of the occlusal vertical dimension will become more reliable if several methods are used simultaneously. Moreover, knowledge of the characteristics of the ageing face is essential. PMID:22292357

den Haan, R; Witter, D J

2011-12-01

157

Vertical tunnel field-effect transistor  

Microsoft Academic Search

The realization of a novel vertically grown tunnel field-effect transistor (FET) with several interesting properties is presented. The operation of the device is shown by means of both experimental results as well as two-dimensional computer simulations. This device consists of a MBE-grown, vertical p-i-n structure. A vertical gate controls the band-to-band tunneling width, and hence the tunneling current. Both n-channel

K. K. Bhuwalka; S. Sedlmaier; A. K. Ludsteck; C. Tolksdorf; J. Schulze; I. Eisele

2004-01-01

158

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.

2012-01-01

159

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

160

Analysis of characteristics of vertical coupling microring resonator  

NASA Astrophysics Data System (ADS)

By using the coupled mode theory and the transfer matrix technique, the optical transfer function is presented for analyzing the size of the waveguide, radius of the microring, free spectral range and amplitude coupling ratio of the vertical coupling microring resonator. Under the central wavelength of 1550 nm, optimization and simulation are performed when the central deviation between the ring and the channel is 0,0.5, 1 ?m, respectively, the 3-dB bandwidth of the spectral response is about 0.21, 0.09, 0.03 nm, and the intensity of the nonresonant light is below -30, -40, -50 dB, respectively.

Yuhai, Wang; Zhengkun, Qin; Chunxu, Wang; Lizhong, Wang

2013-07-01

161

Ultrahigh-Aspect-Ratio Contact Hole Etching  

NASA Astrophysics Data System (ADS)

An ultrasmall, 60nm-diameter, 2um-deep contact hole pattern of BPSG film was successfully fabricated using a poly-Si mask and a magnetically enhanced reactive-ion-etching system. Significantly weaker dependence of etch rate on aspect ratio(AR) was obtained up to AR=30, showing that the energetic ions (and/or neutralized molecules) with a sufficient flux for etching reaction are supplied onto the hole bottom even in such a extremely fine feature. On the other hand, neutral supply of polymer precursors onto the hole bottom (Si substrate) is not sufficient for polymerization in holes with aspect ratios greater than 10, where several energetic particles reach the hole bottoms and contribute to the etching reaction with Si substrates. For features with dimensions below 100nm, processing of vertical profiles is extremely difficult, and problems in the form of bowing at the sidewalls of the holes can occur. The shape of the etched feature and the occurrence of etch stops were shown to be in a trade-off relationship. However, vertical profiles were successfully obtained with diameters greater than 100nm without etch stops. It is possible that ion flux is significantly influenced (reduced) when ions pass through the poly-Si mask, rather than through the BPSG hole. The bowing is associated with bending of the incident ion trajectories, where the first stage of the trajectory change occurs at the mask, and subsequent multiple scattering of ions at the sidewall of the hole can occur. Other factors include sidewall protection by redeposited Si that was sputtered from the poly-Si mask and/or the deposited fluorocarbon polymers, and the effects of ion flux and energy bombarding these deposited materials. In the future, it will be necessary to clarify the details of the mechanisms of these phenomena and to establish technologies to control them. note number.

Ikegami, Naokatsu

1997-10-01

162

Vertical two chamber reaction furnace  

DOEpatents

A vertical two chamber reaction furnace. 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.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. 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.

Blaugher, Richard D. (Evergreen, CO)

1999-03-16

163

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

164

VERTICAL INTEGRATION IN AGRICULTURE AND CONTRACT FARMING  

Microsoft Academic Search

It has been widely argued recently that agriculture is undergoing a process of vertical integration with allied industries. One of the worldwide ways of vertical integration in agriculture is contract farming. Contract farming is a continually evolving process. Worldwide applications of contract farming have shown that the terms of contracts are shaped by their own conditions and varied from product

Erkan Rehber

1998-01-01

165

Marsh vertical accretion via vegetative growth  

Microsoft Academic Search

Coastal marshes accrete vertically in response to sea-level rise and subsidence. Inadequate accretion and subsequent conversion of coastal marshes to open water generally is attributed to inadequate mineral sedimentation because mineral sedimentation is widely assumed to control accretion. Using 137Cs dating to determine vertical accretion, mineral sedimentation, and organic matter accumulation, we found that accretion varied with organic accumulation rather

John A. Nyman; Russel J. Walters; Ronald D. Delaune; William H. Patrick

2006-01-01

166

Control system for a vertical axis windmill  

Microsoft Academic Search

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

Brulle

1983-01-01

167

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

168

Comparison of Horizontal and Vertical Probe Coils.  

National Technical Information Service (NTIS)

The report presents a comparison of horizontal and vertical probe coils of eddy current testing when placed above a homogeneous conducting half space. The trend of the impedance curves for both horizontal and vertical coils against lift-off variation is t...

M. M. Ashraf

1989-01-01

169

THE RELATIONSHIP BETWEEN VERTICAL AND HORIZONTAL MAGNETIC FIELDS IN THE QUIET SUN  

SciTech Connect

Vertical magnetic fields have been known for decades to exist in the internetwork region of the Sun, while the properties of horizontal magnetic fields have only recently been extensively investigated with Hinode. Vertical and horizontal magnetic fields in the internetwork region are considered to be separate entities and have thus far not been investigated in a unified way. We discover a clear positional association between the vertical and horizontal magnetic fields in the internetwork region with Hinode. Essentially, all of the horizontal magnetic patches are associated with the vertical magnetic patches. Alternatively, half of the vertical magnetic patches accommodate the horizontal magnetic patches. These horizontal patches are located around the borders of the vertical patches. The intrinsic magnetic field strength as obtained with the Stokes V line ratio inside the horizontal patches is weak, and is in the subequipartition field regime (B < 700 G), while the field strength outside the horizontal patches ranges from weak to strong (kG) fields. Vertical magnetic patches are known to be concentrated on mesogranular and supergranular boundaries, while the horizontal magnetic patches are found only on mesogranular boundaries. These observations provide us with new information on the origin of the vertical and horizontal internetwork magnetic fields, in a unified way. We conjecture that internetwork magnetic fields are formed by the emergence of small-scale flux tubes with bipolar footpoints, and the vertical magnetic fields of the footpoints are intensified to kG fields due to convective collapse. Resultant strong vertical fields are advected by the supergranular flow, and eventually form the network fields.

Ishikawa, Ryohko [Department of Astronomy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Tsuneta, Saku, E-mail: ryoko.ishikawa@nao.ac.jp [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2011-07-10

170

Confinement improvement of low-aspect-ratio torsatrons  

SciTech Connect

Stellarators with plasma aspect ratios in the range from 3.5 to 5 can be created using the Compact Torsatron configurations. Stable operation at high beta should be possible in these devices if a vertical field coil system is designed to prevent breaking of the magnetic surfaces at finite beta. Direct losses of energetic particles can be high, but the addition of an external quadrupole field can reduce these losses. Optimization criteria and the low-aspect-ratio torsatron configurations obtained are discussed. 22 refs., 12 figs., 1 tab.

Carreras, B.A.; Lynch, V.E.; Dominguez, N.; Leboeuf, J.N.; Lyon, J.F.

1989-03-01

171

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

172

Neptune Clouds Showing Vertical Relief  

NASA Technical Reports Server (NTRS)

This Voyager 2 high resolution color image, taken 2 hours before closest approach, provides obvious evidence of vertical relief in Neptune's bright cloud streaks. These clouds were observed at a latitude of 29 degrees north near Neptune's east terminator. The linear cloud forms are stretched approximately along lines of constant latitude and the sun is toward the lower left. The bright sides of the clouds which face the sun are brighter than the surrounding cloud deck because they are more directly exposed to the sun. Shadows can be seen on the side opposite the sun. These shadows are less distinct at short wavelengths (violet filter) and more distinct at long wavelengths (orange filter). This can be understood if the underlying cloud deck on which the shadow is cast is at a relatively great depth, in which case scattering by molecules in the overlying atmosphere will diffuse light into the shadow. Because molecules scatter blue light much more efficiently than red light, the shadows will be darkest at the longest (reddest) wavelengths, and will appear blue under white light illumination. The resolution of this image is 11 kilometers (6.8 miles per pixel) and the range is only 157,000 kilometers (98,000 miles). The width of the cloud streaks range from 50 to 200 kilometers (31 to 124 miles), and their shadow widths range from 30 to 50 kilometers (18 to 31 miles). Cloud heights appear to be of the order of 50 kilometers (31 miles). This corresponds to 2 scale heights. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.

1989-01-01

173

Selective Epitaxial Growth of Silicon for Vertical Diode Application  

NASA Astrophysics Data System (ADS)

Selectivity control in silicon selective epitaxial growth (SEG) for deep contact patterns, which is one of the key processes for silicon-based stacked devices and cell switches for next generation memories, was studied. Absolute values of selectivity loss during silicon SEG using the most popular H2/dichlorosilane (DCS)/HCl gas system were evaluated using a commercialized inspection tool in 200 mm wafers with real contact patterns. It was revealed that HCl/(DCS+HCl) ratio and the contact structure played a crucial role in suppressing selectivity loss. The number of selectivity losses in an entire wafer was less than 100 when the HCl/(DCS+HCl) ratio was larger than 0.41. The vertical pn diode prepared using the silicon SEG process with elaborate selectivity control showed more remarkable electrical abilities to accommodate current flow than polycrystalline silicon (poly-Si), including the ideality factor and swing, and reverse leakage current.

Lee, Kong-Soo; Yoo, Dae-Han; Han, Jae-Jong; Hyung, Yong-Woo; Kim, Seok-Sik; Kang, Chang-Jin; Jeong, Hong-Sik; Moon, Joo-Tae; Park, Hyunho; Jeong, Hanwook; Kim, Kwang-Ryul; Choi, Byoungdeog

2010-08-01

174

Low aspect ratio tokamak experiment in University of Tokyo  

SciTech Connect

A low aspect ratio tokamak device has been designed and constructed in University of Tokyo. A cylindrical vacuum vessel is employed. The vessel is divided toroidally into two parts insulated each other. In the vessel, central core composed of ohmic coils and a part of toroidal coils is installed. The aluminum shell is installed to keep the vertical and horizontal equilibrium of the plasma. As the result of several efforts to lower the aspect ratio, the predicted minimum value of the aspect ratio reaches less than 1.2. The predicted advantage of low aspect ratio tokamaks is verified by simulation. The analysis of MHD activities and fluctuations will be carried out, after the assembly is completed. 4 refs., 7 figs.

Hanada, K.; Oikawa, T.; Nozawa, K.; Totsuka, H.; Shinohara, K.; Ishiyama, E.; Shinoda, N.; Yamagishi, K.; Toyama, H. [Univ. of Tokyo (Japan)

1995-04-01

175

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

176

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

177

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

PubMed Central

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

Abidin, Nahdiya Zainal; Adam, Mohd Bakri

2013-01-01

178

Vertical structures induced by embedded moonlets in Saturn's rings  

NASA Astrophysics Data System (ADS)

Images of Saturn's rings, taken by the Cassini spacecraft near Saturn's equinox in 2009, show shadows cast by small moonlets embedded in Saturn's rings. Although the resolution of these images is not high enough to see these embedded moonlets directly, the s-shaped structures induced by these moonlets, called propellers, are observable. The shadows cast reveal information about the vertical structure of propellers and therefore about the embedded moonlets [5]. We extend the propeller model [4] into the vertical direction. We use the scattering operator concept [3, 4] to model the gravitational interaction of the embedded moonlet with the ring particles, taking place in a rather small region around the moonlet. Outside this region we describe the ring by hydrodynamic equations. We extend the hydrodynamic description [4] by taking the energy balance equation for the granular temperature T = c2/3 into account, thus getting information about the downstream relaxation of vertical structures induced by the moonlet. We find that the granular temperature decays exponentially to a local equilibrium value after a few orbits. After that the local equilibrium value changes with the surface mass density and hence with the diffusion timescale [4]. Because the evolution of the ratio of thermal speed components cz/cx after the gravitational interaction with the moonlet reaches the equilibrium value after a few collisions per particle [1, 2], we use this equilibrium value to estimate the scale height H / cz/ of the ring. We compare our results of vertical heights and azimuthal lenghts of propellers (like Blériot and Earhart) with measurements taken from Cassini imaging data [5].

Hoffmann, H.; Seiß, M.; Spahn, F.

2012-09-01

179

Vertical Structure Of The Titan Atmosphere From Cassini Uvos Observations  

NASA Astrophysics Data System (ADS)

The reduction and model analysis of Titan vertical atmospheric structure obtained from EUV/FUV stellar and solar occultations from Cassini UVIS experiment will be presented. Related atmospheric emission properties will also be described. The observations show both latitude and longitude dependencies in vertical structure of the hydrocarbon species. Dayside depletion of CH4 and higher order hydrocarbons is observed at altitudes above 880 km, allowing the establishment of limits on diffusion and production rates. Hydrocarbon mixing ratios show latitudinal dependencies of as much as a factor of 4. Higher order hydrocarbons including extinction by aerosols show scale heights larger than CH4 below the exobase, indicating that these species are showing the impact of forcing by chemical production and downward diffusion. The higher order hydrocarbons show density peaks in the 500 -- 700 km region. Aerosol mixing ratios decrease with decreasing altitude as do the higher order hydrocarbons down to 450 km where the distribution makes a sudden transition to constancy with the major species. The aerosols, as the end point of hydrocarbon physical chemistry, constitute the key component determining the state of the atmosphere.

Shemansky, D. E.; Yung, Y.; Zhant, X.; Liu, X.; Kammer, J.

2010-10-01

180

Viability of Cross-Flow Fan for Vertical Take-Off and Landing Aircraft.  

National Technical Information Service (NTIS)

The present study is focused on determining a housing design that, when paired with an off-the-shelf cross-flow fan rotor, will generate a trust- to-weight ratio significant enough to allow for vertical take-off. The commercial computational fluid dynamic...

C. T. Delagrange

2012-01-01

181

Development of a Cross-Flow Fan Rotor for Vertical Take-Off and Landing Aircraft.  

National Technical Information Service (NTIS)

This study determined the optimum number of blades on a 4-inch diameter cross-flow fan rotor such that the rotor produced a thrust-to-weight ratio over one, which will make vertical take-off possible. The commercial computational fluid dynamics software A...

M. J. Martin

2013-01-01

182

Synthesis of vertically aligned carbon nanofibres for interfacing with live systems  

Microsoft Academic Search

The ability to synthesize carbon nanofibres (CNFs) with a high degree of control over their geometry, location and structure via catalytic plasma-enhanced chemical vapour deposition has expanded the possibility of new applications. The nanoscale dimensions and high aspect ratio of vertically aligned carbon nanofibres (VACNFs), along with favourable physical and chemical characteristics, has provided a nanostructured material with properties that

Anatoli Vasilievich Melechko; Ramya Desikan; Timothy E McKnight; Kate L Klein; Philip D Rack

2009-01-01

183

TOPICAL REVIEW: Synthesis of vertically aligned carbon nanofibres for interfacing with live systems  

Microsoft Academic Search

The ability to synthesize carbon nanofibres (CNFs) with a high degree of control over their geometry, location and structure via catalytic plasma-enhanced chemical vapour deposition has expanded the possibility of new applications. The nanoscale dimensions and high aspect ratio of vertically aligned carbon nanofibres (VACNFs), along with favourable physical and chemical characteristics, has provided a nanostructured material with properties that

Anatoli V. Melechko; Ramya Desikan; Timothy E. McKnight; Kate L. Klein; Philip D. Rack

2009-01-01

184

Numerical study on oscillatory convection of cold water in a tall vertical enclosure  

Microsoft Academic Search

The stability of two-dimensional natural convection of water near its density maximum (cold water) inside a vertical rectangular enclosure with an aspect ratio of eight is investigated via a series of direct numerical simulations. The simulations aim to clarify, under the influence of density inversion, the physical nature of the instability mechanism responsible for the laminar buoyancy-driven flow transition from

C. J. Ho; F. J. Tu

1999-01-01

185

Observed Changes in the Vertical Profile of Stratopheric Nitrous Oxide at Thule, Greenland, February - March 1992.  

National Technical Information Service (NTIS)

Using a ground-based mm-wave spectrometer, we have observed stratospheric N2O over Thule, Greenland (76.3 N, 68.4 W) during late February and March, 1992. Vertical profiles of mixing ratio ranging from 16 to 50 km were recovered from molecular emission sp...

L. K. Emmons J. M. Reeves D. T. Shindell R. L. Dezafra

1994-01-01

186

Composite resonator vertical cavity laser diode  

SciTech Connect

The use of two coupled laser cavities has been employed in edge emitting semiconductor lasers for mode suppression and frequency stabilization. The incorporation of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. Composite resonators can be utilized to control spectral and temporal properties within the laser; previous studies of coupled cavity vertical cavity lasers have employed photopumped structures. The authors report the first composite resonator vertical cavity laser diode consisting of two optical cavities and three monolithic distributed Bragg reflectors. Cavity coupling effects and two techniques for external modulation of the laser are described.

Choquette, K.D.; Hou, H.Q.; Chow, W.W.; Geib, K.M.; Hammons, B.E.

1998-05-01

187

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

188

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

189

Vertical stratification in arthropod spatial distribution research.  

PubMed

Spatial heterogeneity within individual host trees is often overlooked in surveys of phytophagous arthropod abundance and distribution. The armored scale Aulacaspis yasumatsui is controlled by the predator Rhyzobius lophanthae to a greater degree on leaves at 75-cm height than on leaves at ground level within its host tree Cycas micronesica. The direct influence of elevation on the predator indirectly generates vertical heterogeneity of the scale insect. Arthropod sampling schemes that fail to include all strata within the vertical profile of the host tree species may generate misleading outcomes. Results indicate that sub-meter increments can reveal significant differences in vertical distribution of phytophagous insects, and that inclusion of observations on other organisms that interact with the target arthropod may illuminate determinants of vertical heterogeneity. PMID:24567772

Marler, Thomas E

2013-11-01

190

Laparoscopic Cholecystectomy after Vertical Banded Gastroplasty.  

PubMed

Following vertical gastroplasty, laparoscopic cholecystectomy has been performed in 27 consecutive patients who developed symptomatic gallstones. Dissection identified structures without difficulty in these patients, and problems were not encountered in these procedures with the laparoscopic technique PMID:10742757

Deitel; Smith; Harmantas

1994-02-01

191

Confocal profilometer with nanometric vertical resolution.  

National Technical Information Service (NTIS)

An optical system is described which is based on the method of Kobayashi et al. The instrument is capable of simultaneous confocal imaging and profilometry with nanometric (nm) vertical resolution. The profile is independent of the reflectivity of the sam...

D. J. Butler A. Horsfall M. Hrynevych P. D. Kearney K. A. Nugent

1992-01-01

192

Vertical Breakout Behavior of the Hydrostatic Anchor.  

National Technical Information Service (NTIS)

The vertical breakout behavior of the hydrostatic anchor depends greatly upon the anchor geometry including anchor diameter and skirt length, the soil strength properties, and the pressure difference between the ambient pressure and that underneath the po...

M. C. Wang V. A. Nacci K. R. Demars

1974-01-01

193

High Performance Vertical Organic Field Effect Transistors.  

National Technical Information Service (NTIS)

This is a productive research project (12 papers in three years) aiming to understand the potential of conjugated polymer in a wide range of organic electronic devices - vertical transistors,solar cells and photodetectors, memory devices, as well as graph...

Y. Yang

2010-01-01

194

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

195

30. BEARING SHOE / VERTICAL / DIAGONAL / UPPER AND ...  

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

30. BEARING SHOE / VERTICAL / DIAGONAL / UPPER AND LOWER CHORD DETAIL OF DECK TRUSS. VIEW TO NORTHEAST. - Abraham Lincoln Memorial Bridge, Spanning Missouri River on Highway 30 between Nebraska & Iowa, Blair, Washington County, NE

196

23. INCLINED END POST / VERTICAL / DIAGONAL / PORTAL ...  

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

23. INCLINED END POST / VERTICAL / DIAGONAL / PORTAL BRACING DETAIL. VIEW TO SOUTHEAST. - Abraham Lincoln Memorial Bridge, Spanning Missouri River on Highway 30 between Nebraska & Iowa, Blair, Washington County, NE

197

Evaluation of a Vertical Conveyorized Electric Grill.  

National Technical Information Service (NTIS)

A continuous vertical electric grill was evaluated from an engineering, food production and food acceptance point of view. Production rate, consistent with the quality criteria established, was found to be 250 hamburger patties per hour. The unit was limi...

R. L. Bernazzani G. Bell

1975-01-01

198

Vertical Datum Conversions for Regional Coastal Management.  

National Technical Information Service (NTIS)

Transforming surveyed elevations and water depths to desired vertical datums is an essential step in building a regional coastal management plan. Regional coastal management plans are based on sediment volume changes and numerical simulations of regional ...

J. M. Wozencraft

2000-01-01

199

Vertically-Shaped Tunable MEMS Resonators  

Microsoft Academic Search

We report the development of tunable comb-resonators that use vertically-shaped comb-fingers as electrostatic springs. By restricting our design modifications to the vertical dimension, the tunability is achieved without increasing the device footprint. Three-dimensional finite element analysis was used to evaluate the effects of geometry and design on electrostatic spring strength and linearity. All structural components were fabricated using gray-scale technology,

Brian Morgan; Reza Ghodssi

2008-01-01

200

On vertical profile of ozone at Syowa  

NASA Technical Reports Server (NTRS)

The difference in the vertical ozone profile at Syowa between 1966-1981 and 1982-1988 is shown. The month-height cross section of the slope of the linear regressions between ozone partial pressure and 100-mb temperature is also shown. The vertically integrated values of the slopes are in close agreement with the slopes calculated by linear regression of Dobson total ozone on 100-mb temperature in the period of 1982-1988.

Chubachi, Shigeru

1994-01-01

201

Strategic choice along the vertical coordination continuum  

Microsoft Academic Search

Starting from the generalized notion of a vertical coordination continuum introduced by Williamson and others, the article more specifically defines the nature of the continuum, especially the array of hybrid strategies. The continuum as presented includes five distinct groups of strategy–spot markets, specification contracts, relation-based alliances, equity-based alliances, and vertical integration. The article then presents a decision making framework that

H. Christopher Peterson; Allen F. Wysocki; Stephen B. Harsh

2001-01-01

202

Long vertical shaft bioreactor of simplified design  

SciTech Connect

An improved long vertical shaft bioreactor for the treatment of degradable waste is provided wherein the head tank or basin surmounting the vertical downcomer and riser chambers is surrounded by a foam oxidation vessel. Conduits are provided between the head tank and the foam vessel through which (A) foam accumulated in the head tank is passed to the foam vessel and (B) through which excess fluid in the head tank may be vented.

Pollock, D.C.

1981-06-09

203

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

204

The vertical structure of the Daphnis wakes  

NASA Astrophysics Data System (ADS)

When Saturn approached its equinox in August 2009 the Sun cast long shadows onto the ring-plane. Many shadows are caused by local vertical perturbations of the otherwise thin disk. The shadows at the Keeler gap edge are, for example, caused by Daphnis' gravitational perturbations. It has been proposed that these large vertical structures (more than 1 km) are caused by the inclination of Daphnis' orbit [1]. Here we show the possibility that also the ring-moon Daphnis on a non-inclined orbit is able to produce these vertical structures. We performed N-body particle simulations and found that particle collisions in the wake crests can significantly increase the vertical dispersion velocity and therefore the height of the corresponding structures. In the case of the Keeler gap edges this can lead to vertical excursions of the ring particles larger than 1 km. We compare and discuss the importance of both processes (moon inclination and particle collisions) for the vertical structure of the Keeler gap edges.

Seiß, M.; Salo, H.; Hoffmann, H.; Spahn, F.; Schmidt, J.

2012-09-01

205

Investigation of diurnal patterns in vertical distributions of pollen in the lower troposphere using LIDAR technique  

NASA Astrophysics Data System (ADS)

The diurnal patterns in pollen vertical distributions in the lower troposphere were investigated by the LIDAR remote sensing technique. Meteorological and pollen concentration data was measured at the surface using a Burkard 7 day recording volumetric spore sampler. An aerosol extinction coefficient and depolarization ratio of 532 nm was obtained from LIDAR measurements in spring (4 May-2 June) 2009 in Gwagnju, Korea. Depolarization ratios from 0.08 to 0.14 were observed only in daytime (09:00-17:00 local time (LT)) during high pollen concentration days from 4 to 9 May. Vertical distributions in the depolarization ratio with time showed a specific diurnal pattern. Depolarization ratios, which varied from 0.08 to 0.14, were measured near the surface in the morning. High depolarization ratios were detected even up to 2.0 km between 12:00 and 14:00 LT but subsequently were observed only close to the surface after 17:00 LT. Low values of depolarization ratios (? 0.05) were detected after 18:00 LT until next morning. During the measurement period, the daily variations in the high depolarization ratios close to the surface showed good agreement with those in surface pollen concentrations, which implies that high depolarization ratios can be attributed to high pollen concentrations. The diurnal characteristics in high values of depolarization ratios were closely associated with turbulent transport, which can be caused by increasing temperature and wind speed and decreasing relative humidity. Continuously measured diurnal and vertical characteristics of pollen data can be further used to enhance the accuracy of the pollen-forecasting model via data assimilation studies.

Noh, Y. M.; Lee, H.; Mueller, D.; Lee, K.; Shin, D.; Shin, S.; Choi, T. J.; Choi, Y. J.; Kim, K. R.

2012-12-01

206

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

207

Vertical R&D Spillovers, Cooperation, Market Structure, and Innovation  

Microsoft Academic Search

This paper studies vertical R&D spillovers between upstream and downstream firms. The model incorporates two vertically related industries, with horizontal spillovers within each industry and vertical spillovers between the two industries. Four types of R&D cooperation are studied: no cooperation, horizontal cooperation, vertical cooperation, and simultaneous horizontal and vertical cooperation. Vertical spillovers always increase R&D and welfare, while horizontal spillovers

Gamal Atallah

2002-01-01

208

Vertical R&D Spillovers, Cooperation, Market Structure, and Innovation  

Microsoft Academic Search

This paper studies vertical R&D spillovers between upstream and downstream firms. The model incorporates two vertically related industries, with horizontal spillovers within each industry and vertical spillovers between the two industries. Four types of R&D cooperation are studied: no cooperation, horizontal cooperation, vertical cooperation, and simultaneous horizontal and vertical cooperation. Vertical spillovers always increase R&D and welfare, while horizontal spillovers

Gamal Atallah

2000-01-01

209

Determination of the operation range of a vertical two-phase closed thermosyphon  

NASA Astrophysics Data System (ADS)

A comprehensive model, proposed for a vertical two-phase closed thermosyphon (TPCT) by the present authors, is further developed by utilizing the criteria for dryout, flooding and boiling limits to investigate the effects of filling ratio on them together, while the available models can just consider one or two limits of them. A new concept named dryout ratio is proposed, which can be used for predicting dryout limit. The empirical correlation and the empirical value, provided by other researchers, are used for predicting flooding and boiling limit, respectively. The experiments with nitrogen as working fluid are performed, and compared with the calculations. The maximum filling ratio is introduced, beyond which the liquid could be carried to condenser and the heat transfer performance can be deteriorated. And then the closed operation range of a vertical TPCT is finally determined, which has not been reported before. The effects of operating pressure and geometries on the range are also analyzed.

Jiao, B.; Qiu, L. M.; Gan, Z. H.; Zhang, X. B.

2012-06-01

210

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

211

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

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

212

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

213

The sex ratio in anencephaly  

Microsoft Academic Search

A review of the data supports the suggestion of Knox (1974) that the sex ratio and incidence of anencephalics vary together within populations, as they are known to do between populations. There seems some doubts, though, whether Knox was correct in hypothesising that the sex ratio of anencephalics varies with their incidence in relation to the dizygotic twinning rate. The

W H James

1979-01-01

214

Misconceptions about the Golden Ratio.  

ERIC Educational Resources Information Center

Typically, the mathematical properties concerning the golden ratio are stated correctly, but much of what is presented with respect to the golden ratio in art, architecture, literature, and aesthetics is false or seriously misleading. Discussed here are some of the most commonly repeated misconceptions promulgated, particularly within mathematics…

Markowsky, George

1992-01-01

215

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

Microsoft Academic Search

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

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

1998-01-01

216

Progressive Ratio Schedules of Reinforcement  

PubMed Central

Pigeons’ pecks produced grain under progressive ratio (PR) schedules, whose response requirements increased systematically within sessions. Experiment 1 compared arithmetic (AP) and geometric (GP) progressions. Response rates increased as a function of the component ratio requirement, then decreased linearly (AP) or asymptotically (GP). Experiment 2 found the linear decrease in AP rates to be relatively independent of step size. Experiment 3 showed pausing to be controlled by the prior component length, which predicted the differences between PR and regressive ratio schedules found in Experiment 4. When the longest component ratios were signaled by different key colors, rates at moderate ratios increased, demonstrating control by forthcoming context. Models for response rate and pause duration described performance on AP schedules; GP schedules required an additional parameter representing the contextual reinforcement.

Killeen, Peter R.; Posadas-Sanchez, Diana; Johansen, Espen Borga; Thrailkill, Eric A.

2009-01-01

217

Trapped, Two-Armed, Nearly Vertical Oscillations in Disks with Toroidal Magnetic Fields  

NASA Astrophysics Data System (ADS)

We have examined the trapping of two-armed (m = 2) nearly vertical oscillations (vertical p-mode) in vertically isothermal (cs = const.) relativistic disks with toroidal magnetic fields. The magnetic fields are stratified so that the Alfvén speed, cA, is constant in the vertical direction. The ratio c²A/c²s in the vertical direction is taken to be a parameter that examines the effects of magnetic fields on wave trapping. We find that the two-armed nearly vertical oscillations are trapped in the inner region of the disks, and their frequencies decrease with an increase of c²A/c²s. The trapped regions of the fundamental (n = 1) and the first-overtone (n = 2) are narrow (less than the length of the Schwarzschild radius, rg), and their frequencies are relatively high (on the order of the angular frequency of disk rotation in the inner region). In contrast to this, the second overtone (n = 3) is trapped in a wide region (a few times rg), and the frequencies are low and tend to zero in the limit of c²A/c²s = 2.0.

Kato, Shoji

2011-02-01

218

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

219

Comparison of diagnostic accuracy of HRT-II and HRT-3 to discriminate glaucomatous and non-glaucomatous eyes  

PubMed Central

Purpose To compare the diagnostic accuracy of the Moorfields Regression Analysis (MRA), parameters, and Glaucoma Probability Score (GPS) from Heidelberg Retinal Tomograph HRT-3 with MRA and parameters from HRT-II in discriminating glaucomatous and healthy eyes in subjects of African (AA) and European ancestry (EA). Design case-control, institutional setting. Methods 78 glaucoma patients (AA=44, EA=34) and 89 age-matched controls (AA=46, EA=33), defined by visual fields and self-reported race were included. Imaging was obtained with HRT-II and data were exported to a computer with the HRT-3 software using the same contour line. Area under Receiver-operating Characteristic [ROC] curves [AUC], sensitivity and specificity were evaluated for whole group, AA and EA separately. Mean disc area was compared between correctly and incorrectly diagnosed eyes by each technique. Results Disc, cup and rim areas from HRT3 were lower than HRT-II (P<0.0001). AUC (sensitivity at 95%-specificity) was 0.85 (54%) for vertical cup-to-disc ratio (VCDR) HRT3, 0.84 (45%) for VCDR HRT-II, and 0.81 (44%) for GPS score at temporal sector. MRA-HRT3 showed greater sensitivity but lower specificity than HRT-II for whole group, AA and EA. GPS classification had lowest specificity. Glaucomatous eyes incorrectly classified by GPS had smaller mean disc area (P=0.0002); controls eyes incorrectly classified had greater mean disc area (P=0.015). Conclusions VCDR from HRT-3 showed higher sensitivity than HRT-II and GPS for the whole group, and AA and EA separately. Sensitivity of MRA improved in HRT-3 with some tradeoff in specificity compared to MRA of HRT-II. GPS yielded erroneous classification associated to optic disc size.

DeLeon-Ortega, Julio E.; Sakata, Lisandro M.; Monheit, Blythe E.; McGwin, Gerald; Arthur, Stella N.; Girkin, Christopher A.

2014-01-01

220

Climatology of tropospheric vertical velocity spectra  

NASA Technical Reports Server (NTRS)

Vertical velocity power spectra obtained from Poker Flat, Alaska; Platteville, Colorado; Rhone Delta, France; and Ponape, East Caroline Islands using 50-MHz clear-air radars with vertical beams are given. The spectra were obtained by analyzing the quietest periods from the one-minute-resolution time series for each site. The lengths of available vertical records ranged from as long as 6 months at Poker Flat to about 1 month at Platteville. The quiet-time vertical velocity spectra are shown. Spectral period ranging from 2 minutes to 4 hours is shown on the abscissa and power spectral density is given on the ordinate. The Brunt-Vaisala (B-V) periods (determined from nearby sounding balloons) are indicated. All spectra (except the one from Platteville) exhibit a peak at periods slightly longer than the B-V period, are flat at longer periods, and fall rapidly at periods less than the B-V period. This behavior is expected for a spectrum of internal waves and is very similar to what is observed in the ocean (Eriksen, 1978). The spectral amplitudes vary by only a factor of 2 or 3 about the mean, and show that under quiet conditions vertical velocity spectra from the troposphere are very similar at widely different locations.

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

1986-01-01

221

Vertical saccades in children: a developmental study.  

PubMed

There are no studies exploring the development of vertical saccades in large populations of children. In this study, we examined the development of vertical saccades in sixty-nine children. Binocular eye movements were recorded using an infrared video oculography system [Mobile EBT(®), e(ye)BRAIN], and movements from both eyes had been analyzed. The gain and the peak velocity of vertical saccades show an up-down asymmetry. Latency value decreases with the age of children, and it does not depend on the direction of the saccades; in contrast, the gain and the peak velocity values of vertical saccades are stable during childhood. We suggest that the up-down asymmetry is developed early, or is innate, in humans. Latencies of vertical saccades develop with the age of children, in relationship with the development of the cortical network responsible for the saccade preparation. In contrast, the precision and the peak velocity are not age-dependent as they are controlled by the cerebellum and brainstem structures. PMID:24352609

Bucci, Maria Pia; Seassau, Magali

2014-03-01

222

High ratio recirculating gas compressor  

SciTech Connect

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

223

Vertical-cavity surface-emitting lasers for flip-chip packaged vertical optical interconnects  

Microsoft Academic Search

Vertical cavity surface emitting lasers (VCSELs) have been fabricated and studied as the optical sources in a vertical optical interconnect application. The VCSELs are to replace LEDs that are currently used in a proof-of-concept demonstration. The advantages of VCSELs ares better power efficiency as sources, higher optical powers, focused beam output, monochromatic operation, and higher modulation bandwidth. The VCSELs used

Sean S. O'Keefe; William J. Schaff; Lester F. Eastman

1994-01-01

224

Incorporation of vertical permeability test results in vertical miscible flood design and operation  

SciTech Connect

The original analysis of the Bigoray Nisku B Pool miscible flood indicated potential coning problems related to the level of vertical permeability. This work presents the results of a vertical permeability test which were incorporated into a coning study. Additional reservoir data along with the rate information from the coning study will be used to revise the original reservoir simulation prediction and depletion strategy.

Gillund, G.N.; Kamal, M.

1983-01-01

225

Reconstructing the vertical profile of humidity on the basis of the vertical profile of temperature  

NASA Technical Reports Server (NTRS)

The vertical profile of humidity in the atmosphere is developed on the basis of the vertical profile of temperature using an empirical formula linking changes in humidity with changes in temperature and altitude. The atmosphere is divided into three layers by altitude, since the condition for the formation of humidity varies with altitude.

Bazlova, T. I.

1974-01-01

226

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

227

Vertical winds in the central polar cap  

NASA Astrophysics Data System (ADS)

Upward vertical winds are observed in the polar cap F-region over Eureka (80°N) during and following sustained polar auroras. This suggests that heating due to particle energy deposition in the F-region is sufficient to generate upward flow. At such times there is a positive divergence in the horizontal winds, indicating that the upward flow is also outward over a >1000 km diameter across the central polar cap. The vertical winds, averaged over a 5-winter period, also have a positive correlation with the horizontal divergences indicating the flow is generally large scale. Downward winds are seen to similarly correspond with negative divergences, and negative IMF Bz, suggesting they may be linked with activity at auroral latitudes. Vertical winds observed over Eureka at other times, appear to be oscillatory with 12-hr and higher harmonic periods suggesting tidal activity. This preliminary conclusion will be tested by examining further winds and aeronomic data.

Guo, W.; McEwen, D. J.

2003-07-01

228

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

229

Purification process for vertically aligned carbon nanofibers  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

230

Stochastic simulation of vertically nonhomogeneous gusts  

NASA Technical Reports Server (NTRS)

The small-scale horizontal gust structure of detailed wind profiles along the vertical in the first 20 km of the atmosphere is a vertically nonhomogeneous process. A linear stochastic model was developed based on the process covariance function. This model was formulated through the use of a scaling hypothesis which transforms the nonhomogeneous gust process into a nondimensional gust process which is homogeneous in a nondimensional gust height coordinate. The velocity scaling parameter for the gust process is the gust standard deviation, and the length scale used to nondimensionalize the altitude is the vertical space lag associated with the first zero of the gust covariance function. State space theory was used to derive a digital filter from the model, which can be readily used to simulate gusts for space vehicle design applications.

Fichtl, G. H.; Perlmutter, M.

1975-01-01

231

Liquid storage tanks under vertical excitation  

SciTech Connect

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

Philippacopoulos, A.J.

1985-01-01

232

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

NASA Technical Reports Server (NTRS)

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

Margolis, Kenneth; Bobbitt, Percy J

1956-01-01

233

Vertical stability, high elongation, and the consequences of loss of vertical control on DIII-D  

SciTech Connect

Recent modifications to the vertical control system for DIII-D has enabled operation of discharges with vertical elongation {kappa}, up to 2.5. When vertical stability is lost, a disruption follows and a large vertical force on the vacuum vessel is observed. The loss of plasma energy begins when the edge safety factor q is 2 but the current decay does not begin until q {approximately}1.3. Current flow on the open field lines in the plasma scrapeoff layer has been measured and the magnitude and distribution of these currents can explain the observed force on the vessel. Equilibrium calculations and simulation of this vertical displacement episode are presented. 7 refs., 4 figs.

Kellman, A.G.; Ferron, J.R.; Jensen, T.H.; Lao, L.L.; Luxon, J.L.; Skinner, D.G.; Strait, E.J.; Reis, E.; Taylor, T.S.; Turnbull, A.D. (General Atomics, San Diego, CA (USA)); Lazarus, E.A. (Oak Ridge National Lab., TN (USA)); Lister, J.B. (Centre de Recherches en Physique des Plasmas, Lausanne (Switzerland))

1990-09-01

234

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

235

Pressure Ratio to Thermal Environments  

NASA Technical Reports Server (NTRS)

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

Lopez, Pedro; Wang, Winston

2012-01-01

236

Arcjet Nozzle Area Ratio Effects  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

237

Arcjet nozzle area ratio effects  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

238

Single transverse mode selectively oxidized vertical-cavity lasers  

NASA Astrophysics Data System (ADS)

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

Choquette, Kent D.; Geib, Kent M.; Briggs, Ronald D.; Allerman, Andrew A.; Hindi, Jana J.

2000-05-01

239

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

240

Turbulent natural convection in vertical parallel-plate channels  

NASA Astrophysics Data System (ADS)

The problem of buoyancy driven turbulent flow in parallel-plate channels is investigated. The investigation is limited to vertical channels of uniform cross-section with different modes of heating. The details of the flow and thermal fields are obtained from the solution of the conservation equations of mass, momentum, and energy in addition to equations of the low Reynolds number turbulence model. The study covers Rayleigh number ranging from 105 to 107 and focuses on the effect of channel geometry on the characteristic of the flow and thermal fields as well as the local and average Nusselt number variation. A Nusselt number correlation has been developed in terms of a modified Rayleigh number and channel aspect ratio for the cases of symmetrically heated isothermal and isoflux conditions.

Badr, H. M.; Habib, M. A.; Anwar, S.; Ben-Mansour, R.; Said, S. A. M.

2006-11-01

241

Vertically aligned carbon nanotube probes for monitoring blood cholesterol  

NASA Astrophysics Data System (ADS)

Detection of blood cholesterol is of great clinical significance. The amperometric detection technique was used for the enzymatic assay of total cholesterol. Multiwall carbon nanotubes (MWNTs), vertically aligned on a silicon platform, promote heterogeneous electron transfer between the enzyme and the working electrode. Surface modification of the MWNT with a biocompatible polymer, polyvinyl alcohol (PVA), converted the hydrophobic nanotube surface into a highly hydrophilic one, which facilitates efficient attachment of biomolecules. The fabricated working electrodes showed a linear relationship between cholesterol concentration and the output signal. The efficacy of the multiwall carbon nanotubes in promoting heterogeneous electron transfer was evident by distinct electrochemical peaks and higher signal-to-noise ratio as compared to the Au electrode with identical enzyme immobilization protocol. The selectivity of the cholesterol sensor in the presence of common interferents present in human blood, e.g. uric acid, ascorbic acid and glucose, is also reported.

Roy, Somenath; Vedala, Harindra; Choi, Wonbong

2006-02-01

242

Tight carbonate intervals; Vertical permeability and threshold pressure estimation models  

SciTech Connect

This paper presents a synergetic study of dense stylolitic intervals within Lower Cretaceous heterogeneous (multilayer) carbonate reservoirs. A new method for characterizing vertical permeability of the dense limestone intervals is developed on the basis of a semiempirical lumped-parameter model. Empirical extension of the method yielded estimates of threshold pressures. The adopted reservoir-description approach provides a purely explicit and interconsistent framework that is especially useful as basic input for detailed full-field simulation-study applications. The concept of excess interfacial tension (IFT) is introduced, and a generalized relationship is proposed for the equivalency of capillary pressure measurements with different fluid parts by use of a correction term to the classical ratio of IFT's that becomes significant in very-low-permeability media.

Mitri, K.T. (Abu Dhabi Co. for Onshore Oil (AE))

1991-12-01

243

Control of dynamic stall phenomenon for vertical axis wind turbine  

NASA Astrophysics Data System (ADS)

In the last years the wind turbine with vertical axis (VAWT) began to be more attractive due benefits in exploitation, the power range covering usually the domain 2 kW-20 kW. But, VAWTs suffer from many complicated aerodynamically problems, of which dynamic stall is an inherent phenomenon when they are operating at low values of tip speed ratio (TSR < 4), and this has a significant impact on vibration, noise, and power output of the VAWTs. For this reason, in the present work we perform a computational investigation of a two-dimensional dynamic stall phenomenon around a NACA0012 airfoil in oscillating motion at relative low Reynolds number (~105). The unsteady flow is investigated numerically using RANS approach with two turbulence models (k-? SST and transition SST). The same analysis was performed to evaluate three flow control methods: two passive and one active.

Frunzulic?, Florin; Dumitrescu, Horia; Dumitrache, Alexandru; Suatean, Bogdan

2013-10-01

244

Critique of the vertical gradient of gravity  

NASA Technical Reports Server (NTRS)

Growing interest in high precision studies of the Earth's gravitational field warrant a critical review of precision requirements to yield useful results. Several problems are now under consideration. All of these problems involve, more or less, the precise value of the vertical gradients of gravity. The principle conclusion from this review is that the essential absence of Free Air Vertical Gravity Gradient control and actual values of gravimeter calibrations require serious attention. Large errors in high topography on official published gravity maps also cannot be ignored.

Hammer, Sigmund

1989-01-01

245

Integrated asymmetric vertical coupler pressure sensors  

NASA Astrophysics Data System (ADS)

Design and analysis of a novel pressure sensor based on a silicon-on-insulator asymmetric integrated vertical coupler is presented. The coupler is composed of a single mode low index waveguide and a thin silicon slab. Wavelength selective optical modulation of asymmetric vertical coupler is examined in detail. Its potential for sensing applications is highlighted as an integrated optical pressure sensor which can be realized by standard silicon micro-fabrication. Sensitivity of transmission of such couplers on refractive index change of silicon slab ensures that they are good candidates for applications requiring high sensitivities.

Kiyat, Isa; Kocabas, Askin; Akcag, Imran; Aydinli, Atilla

2004-08-01

246

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

247

Fundamental and effective Yang-Mills vertices  

SciTech Connect

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

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

2012-09-26

248

Effective vertical beam patterns for ocean acoustic reverberation calculations  

Microsoft Academic Search

A description is given of a concept for using effective vertical beam patterns to perform reverberation calculations in underwater acoustics when the source or receiver has both horizontal and vertical directivity. The concept involves integrating the 3-D beam pattern B (?, ?) over azimuthal angles ? to obtain an effective vertical beam pattern that depends only on the vertical angle

Dale D. Ellis

1991-01-01

249

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

250

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

251

Quantifying asymmetry: Ratios and alternatives.  

PubMed

Traditionally, the study of metric skeletal asymmetry has relied largely on univariate analyses, utilizing ratio transformations when the goal is comparing asymmetries in skeletal elements or populations of dissimilar dimensions. Under this approach, raw asymmetries are divided by a size marker, such as a bilateral average, in an attempt to produce size-free asymmetry indices. Henceforth, this will be referred to as "controlling for size" (see Smith: Curr Anthropol 46 (2005) 249-273). Ratios obtained in this manner often require further transformations to interpret the meaning and sources of asymmetry. This model frequently ignores the fundamental assumption of ratios: the relationship between the variables entered in the ratio must be isometric. Violations of this assumption can obscure existing asymmetries and render spurious results. In this study, we examined the performance of the classic indices in detecting and portraying the asymmetry patterns in four human appendicular bones and explored potential methodological alternatives. Examination of the ratio model revealed that it does not fulfill its intended goals in the bones examined, as the numerator and denominator are independent in all cases. The ratios also introduced strong biases in the comparisons between different elements and variables, generating spurious asymmetry patterns. Multivariate analyses strongly suggest that any transformation to control for overall size or variable range must be conducted before, rather than after, calculating the asymmetries. A combination of exploratory multivariate techniques, such as Principal Components Analysis, and confirmatory linear methods, such as regression and analysis of covariance, appear as a promising and powerful alternative to the use of ratios. Am J Phys Anthropol 154:498-511, 2014. © 2014 Wiley Periodicals, Inc. PMID:24842694

Franks, Erin M; Cabo, Luis L

2014-08-01

252

Vertical cloud distribution in the Uranian atmosphere  

Microsoft Academic Search

In this work, the vertical cloud distribution in the Uranian atmosphere is investigated. We used the method of determinination of the deviation scope of the real atmosphere from homogeneity conditions. The idea of this methods is that the diffusely reflected radiations form at different effective depths in the atmosphere, namely: the strong absorption bands form higher in the atmosphere than

N. M. Kostogryz

2011-01-01

253

Relating River Plume Structure to Vertical Mixing  

Microsoft Academic Search

The structure of a river plume is related to the vertical mixing using an isohaline-based coordinate system. Salinity coordinates offer the advantage of translating with the plume as it moves or expanding as the plume grows. This coordinate system is used to compare the relative importance of different dynamical processes acting within the plume and to describe the effect each

Robert D. Hetland

2005-01-01

254

Sexual and vertical transmission of visceral leishmaniasis.  

PubMed

Visceral leishmaniasis (VL) is an important zoonosis caused by Leishmania infantum, which has in the domestic dog its principal vertebrate host. VL is usually transmitted by phlebotomine sand flies, however atypical routes of transmission have been described. In this review we discuss the the role of sexual and vertical transmissions, and their role in the maintenance of VL in canine populations. PMID:24727504

Turchetti, Andreia P; Souza, Tayse D; Paixão, Tatiane A; Santos, Renato L

2014-01-01

255

Hinged-Blade, Vertical-Shaft Windmill  

NASA Technical Reports Server (NTRS)

Vertical-shaft windmill concept calls for hinged, flapping blades to increase energy-conversion efficiency by reducing wind-energy loss. Hinged Blade Halves unfold to catch wind when moving with it, then fold away from wind when moving against it.

Shultz, B., Jr.

1985-01-01

256

Market structure, innovation and vertical product differentiation  

Microsoft Academic Search

We reassess Arrow's (1962) [Economic Welfare and the Allocation of Resources for Invention, in NBER, The Rate and Direction of Innovative Activity (Princeton University Press, Princeton NJ)] results concerning the effect of market structure on the returns from process innovation. Here we consider product innovations that are vertically differentiated from older products, in the sense of Shaked and Sutton (1982)

Shane Greenstein; Garey Ramey

1998-01-01

257

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

258

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

259

Vertical Feature Mask Feature Classification Flag Extraction  

... Level 2 Vertical Feature Mask feature classification flag value. It is written in Interactive Data Language (IDL) as a callable ... receives as an argument a 16-bit feature classification flag value and prints the feature type information extracted from the bits in the ...

2013-03-28

260

Vertical File Subject Headings KWIK List.  

ERIC Educational Resources Information Center

A subject heading keyword-in-context (KWIK) list for the vertical files at the University of California, Davis, is presented. It is noted that the KWIK list was prepared to assist library users in locating more subject headings for available materials in the various pamphlet collections and that the list is computerized to enable frequent…

Knowles, Em Claire; And Others

261

A Comparison of Methods of Vertical Equating.  

ERIC Educational Resources Information Center

Rasch model vertical equating procedures were applied to three mathematics computation tests for grades six, seven, and eight. Each level of the test was composed of 45 items in three sets of 15 items, arranged in such a way that tests for adjacent grades had two sets (30 items) in common, and the sixth and eighth grades had 15 items in common. In…

Loyd, Brenda H.; Hoover, H. D.

262

Convective Instabilities in Vertical Fractures and Faults  

Microsoft Academic Search

Natural convection of water contained in a vertical fracture or fault in which the temperature increases with depth is strongly influenced by the heat transport processes not only within the water itself but also by the heat transferred to and from the surrounding rock mass. The results of a linear stability analysis indicate that the critical Rayleigh number R* is

Hugh D. Murphy; Geosciences Division

1979-01-01

263

Unidirectional vertical emission from photonic crystal nanolasers  

Microsoft Academic Search

Here, we emphasize the importance of using a bottom reflector to achieve unidirectional vertical emission from an ultra-small light emitter. Specifically, we have considered a photonic crystal slab nanocavity laser placed in the vicinity of a perfect mirror. By choosing near one-wavelength distance between the bottom reflector and the cavity, over 80% of photons generated inside the laser cavity can

Se-Heon Kim; Yong-Hee Lee; Jingqing Huang; Axel Scherer

2009-01-01

264

Vertical nontransovarial transmission of Bartonella in fleas.  

PubMed

Pathogens use diverse pathways to infect host populations by vertical and/or horizontal routes. Horizontal transmission of bacteria belonging to the Bartonella genus via haematophagous vectors is well known. Vertical transmission of Bartonella species was also suggested to occur but its routes remain to be unveiled. In a previous study, we showed the absence of transovarial transmission of Bartonella species OE 1-1 in Xenopsylla ramesis fleas, and that fleas feeding on Bartonella-positive jirds produced Bartonella-positive gut voids. This current study aimed to investigate whether vertical nontransovarial transmission of Bartonella occurs in fleas. For this aim, the X. ramesis-Bartonella sp. OE 1-1 model was used. Four groups of fleas including Bartonella-positive and Bartonella-negative female fleas and larval offspring had access to either Bartonella-negative or Bartonella-positive gut voids and faeces. Sixteen per cent of flea offspring that had access to Bartonella-positive faeces and gut voids became Bartonella positive. Our findings demonstrate that Bartonella-positive flea faeces and gut voids are proper infection sources for flea larvae and indicate that vertical nontransovarial transmission of bartonellae occurs in fleas. This information broadens our understanding of Bartonella transmission routes in flea vectors and enlightens pathways of bartonellae transmission and maintenance in flea populations in nature. PMID:23875817

Morick, Danny; Krasnov, Boris R; Khokhlova, Irina S; Gutiérrez, Ricardo; Gottlieb, Yuval; Harrus, Shimon

2013-09-01

265

ITER Vertical Stability and Shape Control Studies  

NASA Astrophysics Data System (ADS)

A tokamak plasma's vertical stability and shape control system is a critical component of experimental operation. The recent ITER Design Review and subsequent STAC tasks have produced significant modifications to the original ITER vertical stability control system, which used only the outboard coils, PF2-5 (``VS1'' circuit). The addition of a new in-vessel coil set (``VS3'') for vertical control is predicted to augment the control robustness sufficiently to match performance typical of operating devices for similar levels of noise and disturbance amplitude (scaled to minor radius). In this paper we present results of our recent studies of this new system. Linear control-level models are used to analyze controllability and to design controllers, using the GA TokSys toolbox. These controllers are then implemented in more detailed simulations to evaluate their performance under nonlinear conditions. We present Corsica simulations of ITER Baseline 2008 design using these contollers, including controlled and uncontrolled vertical stability events, and flattop and rampdown phases, providing an assessment of the ITER Baseline coil system.

Lodestro, L. L.; Bulmer, R. H.; Meyer, W. H.; Pearlstein, L. D.; Humphreys, D. A.; Walker, M. L.

2010-11-01

266

Vertical pump with free floating check valve  

DOEpatents

A vertical pump with a bottom discharge having a free floating check valve isposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions.

Lindsay, Malcolm (O'Hara Township, Allegheny County, PA)

1980-01-01

267

Thresholds of vertical movement of the body  

Microsoft Academic Search

Simple harmonic motion was used to oscillate vertically 3 S's 8 cm. in 8 sec., 12 sec., or 16 sec. Thresholds ranged between 1.12 and 2.0 cm. per sec. Sensitivity to upward movement was somewhat less than sensitivity to downward movement, the difference ranging between 84% and 93% for the 3 S's. Percent of right responses increased, while percent of

H. Gurnee

1934-01-01

268

Vertical Vergence Calibration for Augmented Reality Displays  

Microsoft Academic Search

Stereo and bi-ocular head-mounted displays (HMDs) require the user to fuse two images into a coherent picture of the threedimensional world. The human visual system performs this task constantly, but when the input images contain both real and graphical depictions, the problem becomes more difficult. A vertical disparity in the graphics causes diplopia for users trying to fuse the real

Mark A. Livingston; Stephen R. Ellis; Sean M. White; S. K. Feiner; A. Lederer

2006-01-01

269

Vertical transport processes in unconfined aquifers  

NASA Astrophysics Data System (ADS)

We derive simple two-dimensional mathematical models describing the unsteady transport of conservative contaminants through an unconfined aquifer with a gently sloping aquiclude subject to advection, recharge, and vertical dispersion. The inclusion of vertical transport terms permits the proper nonreactive analysis of closed and open chemical systems, with the latter allowing dispersion of volatile constituents across the water table. These systems exhibit conservative and pseudoreactive behavior respectively when the pollution is analyzed on a depth-integrated basis, as is common in present one-dimensional models of groundwater contamination. Vertical and longitudinal chloride and total inorganic carbon observations at the well-documented Babylon, Long Island sanitary landfill plume are used to calibrate and test the analyses with a modest level of accuracy, using the vertical dispersivity as a calibration factor in this testing process. The parameter is important in the determination of reaeration rates across the water table and nutrient mixing from below in the related problem of biological transformations near the free surface.

Ostendorf, David W.; Reckhow, David A.; Popielarczyk, David J.

1989-02-01

270

Higher Mode Vertical Vibration of Giant Tanker.  

National Technical Information Service (NTIS)

The preliminary analysis was made on the hull vertical vibration of tankers in which the ship hull is simulated by the model of two parallel beams elastically connected. Each beam represents the side shell and the longitudinal bulkhead respectively, and t...

K. Ohtaka K. Kagawa T. Yamamoto

1969-01-01

271

Electrostatic comb drive for vertical actuation  

SciTech Connect

The electrostatic comb finger drive has become an integral design for microsensor and microactuator applications. This paper reports on utilizing the levitation effect of comb fingers to design vertical-to-the-substrate actuation for interferometric applications. For typical polysilicon comb drives with 2 {micro}m gaps between the stationary and moving fingers, as well as between the microstructures and the substrate, the equilibrium position is nominally 1-2 {micro}m above the stationary comb fingers. This distance is ideal for many phase shifting interferometric applications. Theoretical calculations of the vertical actuation characteristics are compared with the experimental results, and a general design guideline is derived from these results. The suspension flexure stiffnesses, gravity forces, squeeze film damping, and comb finger thicknesses are parameters investigated which affect the displacement curve of the vertical microactuator. By designing a parallel plate capacitor between the suspended mass and the substrate, in situ position sensing can be used to control the vertical movement, providing a total feedback-controlled system. Fundamentals of various capacitive position sensing techniques are discussed. Experimental verification is carried out by a Zygo distance measurement interferometer.

Lee, A. P., LLNL

1997-07-10

272

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

273

Vertical transmission of Babesia microti, United States.  

PubMed

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

Joseph, Julie T; 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

2012-08-01

274

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.

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

275

Phenomenology of Vertical Gas Solid Transport.  

National Technical Information Service (NTIS)

A new model has been developed for the steady vertical pneumatic transport of solids using the previous data for the particle velocities. The experiments were conducted on Pittsburgh seam and Montana Rosebud coals at pressures in the range of 100 psig. Th...

S. T. Tuba G. E. Klinzing M. P. Mathur

1984-01-01

276

Vertical motions in the equatorial middle atmosphere  

NASA Technical Reports Server (NTRS)

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

Weisman, M. L.

1979-01-01

277

High-voltage vertical multijunction solar cell  

Microsoft Academic Search

The vertical multijunction solar cell with covering lens is a photovoltaic device which promises efficiencies greater than that predicted under ideal conditions for any other structure. The mathematical analysis presented here illustrates this statement. In addition the structure described here is capable of a high-voltage output for small solar cell dimensions, a feature which makes this device attractive for many

R. J. Soukup

1976-01-01

278

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

279

Vortex capturing vertical axis wind turbine  

NASA Astrophysics Data System (ADS)

An analytical-numerical study is presented for an innovative lift vertical axis turbine whose blades are designed with vortex trapping cavities that act as passive flow control devices. The unsteady flow field past one-bladed and two-bladed turbines is described by a combined analytical and numerical method based on conformal mapping and on a blob vortex method.

Zannetti, L.; Gallizio, F.; Ottino, G.

2007-07-01

280

Predicting Hail Size Using Model Vertical Velocities.  

National Technical Information Service (NTIS)

A simple test hail growth model is created in order to compare hailstone sizes from model vertical velocities and calculated updrafts from a simple cloud model using forecasted soundings. The models used MM5 model data coinciding with severe hail events c...

G. J. Barnhart

2008-01-01

281

Tailored Airfoils for Vertical Axis Wind Turbines.  

National Technical Information Service (NTIS)

The evolution of a family of airfoil sections designed to be used as blade elements of a vertical axis wind turbine (VAWT) is described. This evolution consists of extensive computer simulation, wind tunnel testing and field testing. The process reveals t...

P. C. Klimas

1984-01-01

282

A dynamic single actuator vertical climbing robot  

Microsoft Academic Search

A climbing robot mechanism is introduced, which uses dynamic movements to climb between two parallel vertical walls. This robot relies on its own internal dynamic motions to gain height, unlike previous mechanisms which are quasi- static. One benefit of dynamics is that it allows climbing with only a single actuated degree of freedom. We show with analysis, simulations and experiments

Amir Degani; Amir Shapiro; Howie Choset; Matthew T. Mason

2007-01-01

283

Second order smoothness over extraordinary vertices  

Microsoft Academic Search

Catmull & Clark subdivision is now a standard for smooth free-form surface modeling. These surfaces are everywhere curvature continuous except at points corresponding to vertices not incident on four edges. While the surface has a continuous tangent plane at such a point, the lack of curvature continuity presents a severe problem for many applications. Topologically, each n-valent extraordinary vertex of

Charles T. Loop

2004-01-01

284

Project Plan for Vertical Lift Machine  

SciTech Connect

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

Ellsworth, G F

2002-08-05

285

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"âa star, a nautilus shell and human hand bonesâand 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,

286

The optic disc is minimal in children with idiopathic intracranial hypertension.  

PubMed

This study sought to characterize the optic disc morphology, particularly the cup-to-disc ratio of the optic nerve head in children with idiopathic intracranial hypertension. The medical charts and digital optic disc photos of children with confirmed diagnosis of idiopathic intracranial hypertension were reviewed retrospectively. The optic disc area, cup area, and cup-to-disc ratio were measured digitally using VISUPAC software, and the mean values of those parameters were compared to the published norms. Of children with idiopathic intracranial hypertension, 83% had absence of the physiological cup of the optic disc, compared to 10% of children in the general population of the same age. The median disc area was 2.2 mm(2), and median cup area was 0.0mm(2), compared to the published norms of 2.69 mm(2) and 0.44 mm(2), respectively. There is very significantly high prevalence of small optic disc cups in children with idiopathic intracranial hypertension, with the cup being absent on majority of cases in our patient cohort. This may signal an underlying systemic predisposition to the development of intracranial hypertension. PMID:23034982

Dai, Shuan; Trimboli, Carmelina; Buncic, J Raymond

2013-10-01

287

Morphologic assessment for glaucoma in the Multicenter Uveitis Steroid Treatment (MUST) Trial  

PubMed Central

Purpose To compare Reading Center (RC) cup-to-disc ratio (CDR) assessment from stereoscopic photographs with clinician estimation in a uveitis clinical trial. Methods Clinical estimation of CDR was performed by ophthalmologists via dilated biomicroscopy. Photographic evaluation was performed at an independent RC by masked, certified evaluators. Quality control was performed by repeat grading of 77 randomly selected images. Results Among 481 eyes with uveitis, 353 eyes had clinical and photographic grades for CDR. Agreement between clinical and RC grading was fair, with exact agreement in 29%. Agreement within 0.1 and 0.2 CDR were 70% and 93%, respectively (wkappa=0.34). Inter-grader reproducibility at the RC was better (wkappa=0.59, ICC 0.74). Conclusion Morphologic assessment of cup to disc ratio is an important outcome and safety measure for determining glaucomatous damage in clinical trials. Masked RC measurements are more likely to be accurate than biomicroscopic grading in identifying meaningful anatomical change associated with glaucoma.

Gangaputra, Sapna; Altaweel, Michael M.; Peng, Qian; Friedman, David S.; Rao, P. Kumar; Foster, C. Stephen; Kim, Rosa Y.; Reed, Susan B.; Srivastava, Sunil K.; Wong, Ira G.; Kempen, John H.

2013-01-01

288

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

289

Simulation of tail buffet using delta wing-vertical tail configuration  

NASA Technical Reports Server (NTRS)

Computational simulation of the vertical tail buffet problem is accomplished using a delta wing-vertical tail configuration. Flow conditions are selected such that the wing primary-vortex cores experience vortex breakdown and the resulting flow interacts with the vertical tail. This multidisciplinary problem is solved successively using three sets of equations for the fluid flow, aeroelastic deflections and grid displacements. For the fluid dynamics part, the unsteady, compressible, full Navier-Stokes equations are solved accurately in time using an implicit, upwind, flux-difference splitting, finite-volume scheme. For the aeroelastic part, the aeroelastic equation for bending vibrations is solved accurately in time using the Galerkin method and the four-stage Runge-Kutta scheme. The grid for the fluid dynamics computations is updated every few time steps using a third set of interpolation equations. The computational application includes a delta wing of aspect ratio 1 and a rectangular vertical tail of aspect ratio 2, which is placed at 0.5 root-chord length downstream of the wing trailing edge. The wing angle of attack is 35 deg and the flow Mach number and Reynolds number are 0.4 and 10,000, respectively.

Kandil, Osama A.; Kandil, Hamdy A.; Massey, Steven J.

1993-01-01

290

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

291

Optimized signal to noise ratio of a PMT based detector system in Mie-Lidar  

Microsoft Academic Search

Signal to noise ratio calculations are made for a Mie-Lidar system which uses photomultiplier tube (PMT) as a detector. Power received by the Lidar system from different altitudes is calculated considering four different model vertical profiles of aerosols representing urban and background continent conditions, with and without stratospheric volcanic aerosol layer. The minimum detectable energy of the backscattered laser pulse

Y. B. Acharya; A. Jayaraman

2006-01-01

292

Stability and control characteristics of an airplane model having a 45.1 degree swept-back wing with aspect ratio 2.50 and taper ratio 0.42 and a 42.8 degree swept-back horizontal tail with aspect ratio 3.87 and taper ratio 0.49  

NASA Technical Reports Server (NTRS)

Tests were made of an airplane model having a 45.1 degree swept-back wing with aspect ratio 2.50 and taper ratio 0.42 and a 42.8 degree swept-back horizontal tail with aspect ratio 3.87 and taper ratio 0.49 to determine its low-speed stability and control characteristics. The test Reynolds number was 2.87 x 10(6) based on a mean aerodynamic chord of 2.47 feet except for some of the aileron tests which were made at a Reynolds number of 2.05 x 10(6). With the horizontal tail located near the fuselage juncture on the vertical tail, model results indicated static longitudinal instability above a lift coefficient that was 0.15 below the lift coefficient at which stall occurred. Static longitudinal stability, however, was manifested throughout the life range with the horizontal tail located near the top of the vertical tail. The use of 10 degrees negative dihedral on the wing had little effect on the static longitudinal stability characteristics. Preliminary tests of the complete model revealed an undesirable flat spot in the yawing-moment curves at low angles of attack, the directional stability being neutral for yaw angles of plus-or-minus 2 degrees. This undesirable characteristic was improved by replacing the thick original vertical tail with a thin vertical tail and by flattening the top of the dorsal fairing.

Schuldenfrei, Marvin; Comisarow, Paul; Goodson, Kenneth W

1947-01-01

293

MEASUREMENT OF BI-DIRECTIONAL AMMONIA FLUXES OVER SOYBEAN USING MODIFIED BOWEN-RATIO TECHNIQUE  

EPA Science Inventory

Measurements of bi-directional ammonia exchange over a fertilized soybean canopy are presented for an 8-week period during the summer of 2002. The modified Bowne-ratio approach was used to determine fluxes from vertical NH3 and temperature gradients in combination with eddy covar...

294

Vertical export of particulate organic carbon: Attenuation, composition and loss rates in the northern Barents Sea  

NASA Astrophysics Data System (ADS)

The fate of primary production (PP) is closely linked to the ecosystem structure in aquatic environments. High pelagic consumption and recycling reduce quantity and quality of vertically exported organic material, while low to moderate pelagic consumption allows more carbon of higher quality to reach benthic communities. To evaluate the driving forces influencing changes in quantity and composition of vertical flux with depth and environmental conditions in ice-covered waters, short-term sediment trap deployments at 6-8 depths from 20 to 200 m were conducted. Eleven stations in the northern Barents Sea were investigated during early, peak and late bloom scenarios in 2003-2005. Vertical particulate organic carbon (POC) export ranged 140-760 mg C m -2 d -1 at 30 m and 58-720 mg C m -2 d -1 at 90 m depth. Strongest vertical carbon flux attenuation was observed during peak bloom scenarios. The pycnocline always defined the depth of the strongest attenuation. The POC export was highly correlated with Chl a flux ( r2=0.89) and with a low POC/Chl a ratio, this indicates that fresh material is being exported to depth. A tight coupling between POC export at 90 m and particulate PP ( r2=0.61) was observed and suggests that on an average 36% of daily PP was exported as POC. Deep vertical mixing observed in the Polar Front or less stable water masses did, however, enhance the vertical export and loss rates considerably. Annual estimates of vertical POC export to PP, suggests weaker retention, and thus stronger pelagic-benthic coupling in Arctic compared to the Atlantic region of the Barents Sea.

Reigstad, Marit; Wexels Riser, Christian; Wassmann, Paul; Ratkova, Tatjana

2008-10-01

295

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

296

Higgs boson hadronic branching ratios at the ILC  

SciTech Connect

We present a study of the Higgs boson decay branching ratios to bb, cc, and gluons, one of the cornerstones of the physics program at the International Linear Collider. A standard model Higgs boson of 120 GeV mass, produced in the Higgs-strahlung process at {radical}(s)=250 GeV, was investigated using the full detector simulation and reconstruction procedures. The analysis was performed in the framework of the Silicon Detector concept with full account of inclusive standard model backgrounds. The selected decay modes contained two heavy flavor jets in the final state and required excellent flavor tagging through precise reconstruction of interaction and decay vertices in the detector. A new signal discrimination technique using correlations of neural network outputs was used to determine the branching ratios and estimate their uncertainties, 4.8%, 8.4%, and 12.2% for bb, cc, and gluons, respectively.

Banda, Yambazi; Lastovicka, Tomas; Nomerotski, Andrei [University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)

2010-08-01

297

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

298

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

299

Surface Area to Volume Ratio  

NSDL National Science Digital Library

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

2012-10-16

300

Farey Sums and Understanding Ratios  

ERIC Educational Resources Information Center

Mathematical problems when solved with different approaches deepen the understanding of topics learned. It is reported that weighted average is commonly used in applications and the relationship between all the ratios involved in the problem emphasized could be learned from Farey sum of two fractions.

Mihail, Ioana

2004-01-01

301

Declustering Using Golden Ratio Sequences  

Microsoft Academic Search

In this paper we propose a new data declustering scheme for range queries. Our schemeis based on Golden Ratio Sequences (GRS), which have found applications in broadcast disks,hashing, packet routing, etc. We show by analysis and simulation that GRS is nearly the bestpossible scheme for 2-dimensional range queries. Specifically, it is the best possible scheme whenthe number of disks (M

Randeep Bhatia; Rakesh K. Sinha; Chung-min Chen

2000-01-01

302

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

303

High-Performance Poly-Si Vertical Nanowire Thin-Film Transistor and the Inverter Demonstration  

Microsoft Academic Search

In this letter, gate-all-around vertical nanowire (NW) polycrystalline silicon (poly-Si) thin-film transistors (TFTs) are demonstrated using a CMOS-compatible process. Both N- and P-TFT devices (with gate length down to 100 nm and a wire diameter of ?30 nm) exhibit good transistor performance, e.g., high Ion\\/Ioff ratio of > 10 6 , low subthreshold slope (SS ? 100 mV\\/dec), and reasonable

T. T. Le; H. Y. Yu; Y. Sun; N. Singh; X. Zhou; N. Shen; G. Q. Lo; D. L. Kwong

2011-01-01

304

A silicon-on-glass Z-axis accelerometer with vertical sensing comb capacitors  

Microsoft Academic Search

A Z-axis accelerometer with asymmetrical vertical sensing comb capacitors and high aspect ratio single crystal mechanical structures is presented. A 5-mask silicon-on-glass (SOG) process combined with silicon\\/glass anodic bonding and multiple deep ion reactive etching (DRIE) is used to fabricate the accelerometer. With the specially designed out-of-plane springs, the accelerometer shows a cross-axis sensitivity of 0.46%. The scale factor and

Jiankun Wang; Zhenchuan Yang; Guizhen Yan

2012-01-01

305

Vertical distribution of chlorofluoromethanes in the upper troposphere and lower stratosphere  

Microsoft Academic Search

Vertical profiles of CCl4, CFCl3, and CF2Cl2 mixing ratios in the upper troposphere and lower stratosphere have been measured on four flights with chartered aircraft, type HS 125. The flights were carried out in November and December 1976 over Europe at latitudes between 50 and 60°N. At least eight air samples were taken during each ascent and descent of the

W. Seiler; F. Müller; H. Oeser

1978-01-01

306

Visualization by PIV of dynamic stall on a vertical axis wind turbine  

Microsoft Academic Search

The aerodynamic behavior of a vertical axis wind turbine (VAWT) is analyzed by means of 2D particle image velocimetry (PIV),\\u000a focusing on the development of dynamic stall at different tip speed ratios. The VAWT has an unsteady aerodynamic behavior\\u000a due to the variation with the azimuth angle ? of the blade’s sections’ angle of attack, perceived velocity and Reynolds number.

Carlos Simão Ferreira; Gijs van Kuik; Gerard van Bussel; Fulvio Scarano

2009-01-01

307

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

308

Air/fuel ratio regulator  

SciTech Connect

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

Simko, A.

1980-07-22

309

Conditional generation of path-entangled optical vertical bar N,0>+ vertical bar 0,N> states  

SciTech Connect

We propose a measurement protocol to generate path-entangled vertical bar N,0>+ vertical bar 0,N> states conditionally from two pulsed type II optical parametric oscillators. We calculate the fidelity of the produced states and the success probability of the protocol. The trigger detectors are assumed to have finite dead time, and for short pulse trigger fields they are modeled as on-off detectors with finite efficiency. Continuous-wave operation of the parametric oscillators is also considered.

Nielsen, Anne E. B.; Moelmer, Klaus [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

2007-06-15

310

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

SciTech Connect

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

Miller, S.

1988-05-01

311

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

312

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

313

Effects of frequency, magnitude, damping, and direction on the discomfort of vertical whole-body mechanical shocks  

Microsoft Academic Search

The discomfort of seated subjects exposed to a wide range of vertical mechanical shocks has been studied experimentally. Shocks were produced from responses of single degree-of-freedom models with 16 fundamental frequencies (0.5–16Hz) and four damping ratios (0.05, 0.1, 0.2 and 0.4) to half-sine force inputs. Shocks with a damping ratio of 0.4 were presented with both polarities. Each type of

Se-Jin Ahn; Michael J. Griffin

2008-01-01

314

Coupled Resonator Vertical Cavity Laser Diodes  

SciTech Connect

For many applications, the device performance of edge emitting semiconductor lasers can be significantly improved through the use of multiple section devices. For example, cleaved coupled cavity (C3) lasers have been shown to provide single mode operation, wavelength tuning, high speed switching, as well as the generation of short pulses via mode-locking and Q-switching [1]. Using composite resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the coupling between the monolithic cavities, incorporate passive or active resonators which are spectrally degenerate or detuned, and to fabricate these devices in 2-dimensional arrays. Composite resonator vertical cavity lasers (CRVCL) have been examined using optical pumping and electrical injection [2-5]. We report on CRVCL diodes and show that efficient modulation of the laser emission can be achieved by either forward or reverse biasing the passive cavity within a CRVCL.

Choquette, K.D.; Chow, W.W.; Fischer, A.J.; Allerman, A.A.; Hou, H.Q.; Geib, K.M.

1999-07-22

315

Baroclinic instability in vertically discrete systems  

NASA Technical Reports Server (NTRS)

The Charney-Phillips (1953) standard vertical grid for quasi-geostrophic models is compared with the Lorenz (1960) vertical grid (which departs from the standard grid by carrying horizontal velocity and potential temperature at same levels) in the framework of the quasi-geostrophic potential vorticity equation and baroclinic instability. It is demonstrated that the Charney-Phillips grid makes it possible to maintain important dynamical constraints on quasi-geostrophic flow, such as the conservation of quasi-geostrophic potential vorticity through horizontal advection and resulting integral constraints. The Lorenz grid, on the other hand, is not straightforward even to define quasi-geostrophic potential vorticity. Moreover, due to an extra degree of freedom in potential temperature, the Lorenz grid can falsely satisfy the necessary condition for baroclinic instability near the lower and the upper boundaries.

Arakawa, Akio; Moorthi, Shrinivas

1988-01-01

316

Vertical fracture containment during massive hydraulic fracturing  

SciTech Connect

Massive hydraulic fractures are projected to play a major role in the recovery of the tremendous reserves of gas tied up in the tight gas sands of the Deep Basin of N. Alberta and British Columbia. One of the major problems in designing fractures in such formations is the uncertain vertical extent of these fractures: fracture containment. This work presents a procedure for predicting the vertical extent of fractures in multi-layered formations with varying material properties and tectonic stresses. The numeric procedure uses the finite element technique for the rock deformation calculations and employs special high order, crack-tip elements to improve the accuracy of stress intensity calculations. Furthermore, it makes use of the powerful numeric technique of static condensation to reduce computer memory and computation time. The elastic deformation calculation can be coupled to a fluid flow model to predict dynamic fracture growth.

Cormack, D.E.; Fung, R.L.; Vijayakumar, S.

1983-01-01

317

Partial vertical laryngectomy for recurrent glottic carcinoma.  

PubMed

Partial vertical laryngectomy for recurrent glottic carcinoma was performed in 61 patients according to stringent criteria. The great majority of the recurrent tumours appeared within 2 years of radiotherapy (80%). The mean follow-up after surgery was 79 months. At 5 years 85% of the patients were free of local recurrence. Nine patients (15%) developed a local recurrence; eight of them underwent total laryngectomy; one patient refused the operation and died. Seven patients died of other causes. The actuarial overall survival rate was 88% at 5 years. Post-operative complications were seen in 12 patients (20%); nine of these patients developed airway problems. One patient underwent total laryngectomy for severe aspiration, the others finally were decannulated. The results of this study indicate that partial vertical hemilaryngectomy for irradiation failures is a safe procedure with good results without undue morbidity. PMID:7634526

Kooper, D P; van den Broek, P; Manni, J J; Tiwari, R M; Snow, G B

1995-04-01

318

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 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. {copyright} {ital 1999 American Institute of Physics.}

Fischer, A.J.; Choquette, K.D.; Chow, W.W.; Hou, H.Q.; Geib, K.M. [Center for Compound Semiconductor Science and Technology, Sandia National Labs, Albuquerque, New Mexico 87185 (United States)] [Center for Compound Semiconductor Science and Technology, Sandia National Labs, Albuquerque, New Mexico 87185 (United States)

1999-11-01

319

Transitions Within a Vertically Confined Plasma Crystal  

NASA Astrophysics Data System (ADS)

Dusty plasmas consist of an ionized gas containing small (usually negatively charged) particles. Dusty plasmas are of interest in both astrophysics and space physics as well as in research in plasma processing and nanofabrication. In this work, the formation of plasma crystals confined in an external one-dimensional parabolic potential well is simulated for a normal experimental environment employing a computer code called BOX_TREE. Such crystals are layered systems, with each layer a 2D lattice composed of grain particles. The number of layers is dependent in part upon the external potential parameter. The transition from 1 to 2 layers is specifically analyzed with dispersion relations for the vertical dust lattice wave obtained at the transition point and the transition shown to be induced by the vertical dust lattice instability.

Qiao, Ke; Hyde, Truell

2004-10-01

320

Extreme wave runup on a vertical cliff  

NASA Astrophysics Data System (ADS)

Wave impact and runup onto vertical obstacles are among the most important phenomena which must be taken into account in the design of coastal structures. From linear wave theory, we know that the wave amplitude on a vertical wall is twice the incident wave amplitude with weakly nonlinear theories bringing small corrections to this result. In this present study, however, we show that certain simple wave groups may produce much higher runups than previously predicted, with particular incident wave frequencies resulting in runup heights exceeding the initial wave amplitude by a factor of 5, suggesting that the notion of the design wave used in coastal structure design may need to be revisited. The results presented in this study can be considered as a note of caution for practitioners, on one side, and as a challenging novel material for theoreticians who work in the field of extreme wave-coastal structure interaction.

Carbone, Francesco; Dutykh, Denys; Dudley, John M.; Dias, FréDéRic

2013-06-01

321

Order in vertically aligned carbon nanotube arrays  

SciTech Connect

We report the direct measurements on the bulk morphology of vertically aligned multiwalled carbon nanotube (CNT) arrays using small angle neutron scattering (SANS). SANS measurements at different heights of CNT arrays corresponding to different stages of the growth reveal increasing alignment order along the thickness and two distinctly different CNT morphologies. The observations suggest that the evolution of the macroscopic CNT morphologies be driven by competing collective growth and spatial constraints.

Wang, Hsin [ORNL; Xu, Z [Michigan State University, East Lansing; Eres, Gyula [ORNL

2006-01-01

322

Vertical winds in the central polar cap  

Microsoft Academic Search

Upward vertical winds are observed in the polar cap F-region over Eureka (80°N) during and following sustained polar auroras. This suggests that heating due to particle energy deposition in the F-region is sufficient to generate upward flow. At such times there is a positive divergence in the horizontal winds, indicating that the upward flow is also outward over a >1000

W. Guo; D. J. McEwen

2003-01-01

323

Multistring Vertices and Hyperbolic Kac Moody Algebras  

Microsoft Academic Search

Multistring vertices and the overlap identities which they satisfy are\\u000aexploited to understand properties of hyperbolic Kac Moody algebras, and\\u000a$E_{10}$ in particular. Since any such algebra can be embedded in the larger\\u000aLie algebra of physical states of an associated completely compactified\\u000asubcritical bosonic string, one can in principle determine the root spaces by\\u000aanalyzing which (positive norm) physical

R. W. Gebert; H. Nicolai; P. C. West

1995-01-01

324

Thermal analysis of vertically integrated circuits  

Microsoft Academic Search

In this paper, a thermal analysis of Vertically Integrated Circuits (VIC) is presented for the first time. Based on a 1-D model, temperature differences in VICs of less than 10°C are evaluated for most practical applications. Detailed 3-D investigations show that self-heating of MOSFETs in the upper chip-layers of a VIC is more pronounced than in bulk CMOS and that

M. B. Kleiner; S. A. Kuhn; P. Ramm; W. Weber

1995-01-01

325

Hydrogen-Oxygen Vertical Brazing Furnace  

Microsoft Academic Search

A specially designed hydrogen-oxygen vertical flame furnace was constructed for brazing together the copper pieces of the accelerator structure for Stanford's Two-Mile Linear Electron Accelerator. To date, over 60 000 braze joints have been made without a leak appearing in any joint even though the brazed section operates at less than 10–8 Torr pressure. The accelerator structure is a disk

Arnold L. Eldredge

1965-01-01

326

Broadband Horizontal and Vertical Spatial Coherence Measurements  

NASA Astrophysics Data System (ADS)

Initial results of broadband (1 to 10 kHz) spatial coherence measurements taken during the June 2003 shallow-water (8 m) propagation experiments will be presented. The results will show spatial coherence estimates over a 12 m long horizontal array and over a 6 m vertical array. The data was taken over a range of sea states and at ranges of approximately 70 and 150 m.

Ruppel, Timothy H.; Stanic, Steve; Norton, Guy V.; Meredith, Roger W.; Kennedy, Edgar T.; Goodman, Ralph R.; Wilson, Marcia A.

2004-11-01

327

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

328

Boston University Physics Applets: Vertical Circular Motion  

NSDL National Science Digital Library

This web page is an interactive physics simulation relating to circular motion. An object on a vertical circular pathway is shown, accompanied by an animated free-body diagram. Users may view the motion in steps to observe the net force as the object changes speed due to gravitation. This item is part of a collection of similar simulation-based activities developed for students of introductory physics.

Duffy, Andrew

2008-08-01

329

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

330

Inverse scattering problem for quantum graph vertices  

SciTech Connect

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

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

2011-06-15

331

Coupled resonator vertical cavity laser diodes  

Microsoft Academic Search

Summary form only given. We report on electrically injected coupled resonator vertical-cavity laser (CRVCL) diodes, including two novel modulation approaches. We show a side sketch of the CRVCL which consists of a lower active resonator containing 3 InGaAs quantum wells and a passive upper resonator composed of undoped GaAs. In the bottom active cavity we employ selective oxidation of AlGaAs

KENT D. CHOQUETTE; WENG W. CHOW; ARTHUR J. FISCHER; A. A. Allerman; HONG Q. HOU; K. M. Geib

1999-01-01

332

STRATEGIC CHOICE ALONG THE VERTICAL COORDINATION CONTINUUM  

Microsoft Academic Search

Fundamental changes are underway in the U.S. agri-food system, changes that are altering traditional marketing relationships. Parts of the food system are becoming tightly integrated, such as the poultry subsector and, increasingly, the pork subsector. The tightening of vertical linkages has been characterized by movement from open markets to various forms of managed coordination, e.g. contracting, strategic alliances, and single

H. Christopher Peterson; Allen F. Wysocki

1998-01-01

333

Vertical flight path steering system for aircraft  

NASA Technical Reports Server (NTRS)

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

Lambregts, Antonius A. (Inventor)

1983-01-01

334

Vertical Cavity Surface Emitting Lasers Photonics  

NASA Astrophysics Data System (ADS)

We overview vertical cavity surface emitting lasers (VCSEL) photonics, that stands for photonics in relation to VCSEL based on the lecture at the 11th Microoptics Conference (MOC’06). We will survey its progress along with the development of VCSELs since 1977. This VCSEL photonics will open up a new field of technology and applications because of its merits, such as compactness, low power consumption, high speed capability and arrayed configuration.

Iga, Kenichi

2006-08-01

335

Vertical-Cavity Surface-Emitting Lasers  

Microsoft Academic Search

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

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

336

Nanoelectromechanical switches with vertically aligned carbon nanotubes  

NASA Astrophysics Data System (ADS)

Electromechanical switching devices have been fabricated successfully employing vertically grown multiwalled carbon nanotubes (MWCNTs) from the prepatterned catalyst dots on the patterned device electrodes. The devices show various interesting switching characteristics depending on the length and the number of MWCNTs used. The device design not only simplifies the fabrication process, but also improves the integration density greatly. The device has a great potential in realizing technically viable nanoelectromechanical systems, such as switch, memory, fingers, or grippers.

Jang, J. E.; Cha, S. N.; Choi, Y.; Amaratunga, Gehan A. J.; Kang, D. J.; Hasko, D. G.; Jung, J. E.; Kim, J. M.

2005-10-01

337

Diffusion weighted vertical gradient and spin echo.  

PubMed

In this work, diffusion weighting and parallel imaging is combined with a vertical gradient and spin echo data readout. This sequence was implemented and evaluated on healthy volunteers using a 1.5 and a 3 T whole-body MR system. As the vertical gradient and spin echo trajectory enables a higher k-space velocity in the phase-encoding direction than single-shot echo planar imaging, the geometrical distortions are reduced. When combined with parallel imaging such as generalized autocalibrating partially parallel acquisition, the geometric distortions are reduced even further, while also keeping the minimum echo time reasonably low. However, this combination of a diffusion preparation and multiple refocusing pulses during the vertical gradient and spin echo readout, generally violates the Carr-Purcell-Meiboom-Gill condition, which leads to interferences between echo pathways. To suppress the stimulated echo pathway, refocusing pulses with a sharper slice profiles and an odd/even crusher variation scheme were implemented and evaluated. Being a single-shot acquisition technique, the reconstructed images are robust to rigid-body head motion and spatially varying brain motion, both of which are common sources of artifacts in diffusion MRI. PMID:23008151

Engström, Mathias; Bammer, Roland; Skare, Stefan

2012-12-01

338

[Vertical talus: current diagnostic and therapy options].  

PubMed

Congenital vertical talus is a rare condition which presents as an isolated deformity or in association with neuromuscular and/or genetic disorders. Pathoanatomically the deformity shows a dislocated talonavicular and subtalar joint. The etiology and pathogenesis are still not finally determined although in some cases a genetic basis has been identified. The clinical picture is that of a flat, convex longitudinal arch with abduction and dorsiflexion of the forefoot and an elevated heel. Clinical diagnosis is confirmed by plain radiographic imaging. Congenital vertical talus should not be confused with other deformities of the foot, such as congenital oblique talus, flexible flat feet or pes calcaneus. The object of treatment of congenital vertical talus is to restore a normal anatomical relationship between the talus, navicular and calcaneus to obtain a pain-free foot. Major reconstructive surgery has been reported to be effective but is associated with substantial complications. Good early results of a modified non-operative treatment using serial manipulation, cast treatment and minimally invasive surgery may change therapeutic concepts. PMID:23685500

Arbab, D; Rath, B; Quack, V; Lüring, C; Tingart, M

2013-06-01

339

Modification of vertical hemispherotomy for refractory epilepsy.  

PubMed

Delalande's vertical hemispherotomy is an innovative evolution of hemispherectomy in minimizing brain resection. We report our modification for this surgical procedure. We modified the original procedure in two aspects for the purpose of less brain resection and confirmation of the complete disconnection. Firstly, all procedures were done via an interhemispheric route instead of a transcortical route. Secondly, we set the anterior disconnection plane as the one that connects the anterior end of the choroidal fissure to the anterior end of the foramen of Monro, instead of the former to the subcallosal area. We applied this modified vertical hemispherotomy to 7 cases. Four cases were children with hemimegalencephaly and other 3 were adults with ulegyric hemisphere. Surgical procedure was completed without complication in all cases. There was no case that required CSF shunting. Seizure outcome was Engel's class I in 6 and class IV in 1. Postoperative MRI revealed complete disconnection of the affected hemisphere in all patients. We reported our modification of vertical hemispherotomy. Although these are minor modifications, they further minimized brain resection and may serve for less invasiveness of procedure and improvement in completeness of disconnection and its confirmation during surgery. PMID:23422258

Kawai, Kensuke; Morino, Michiharu; Iwasaki, Masaki

2014-02-01

340

Vertical nanopillars for highly localized fluorescence imaging  

PubMed Central

Observing individual molecules in a complex environment by fluorescence microscopy is becoming increasingly important in biological and medical research, for which critical reduction of observation volume is required. Here, we demonstrate the use of vertically aligned silicon dioxide nanopillars to achieve below-the-diffraction-limit observation volume in vitro and inside live cells. With a diameter much smaller than the wavelength of visible light, a transparent silicon dioxide nanopillar embedded in a nontransparent substrate restricts the propagation of light and affords evanescence wave excitation along its vertical surface. This effect creates highly confined illumination volume that selectively excites fluorescence molecules in the vicinity of the nanopillar. We show that this nanopillar illumination can be used for in vitro single-molecule detection at high fluorophore concentrations. In addition, we demonstrate that vertical nanopillars interface tightly with live cells and function as highly localized light sources inside the cell. Furthermore, specific chemical modification of the nanopillar surface makes it possible to locally recruit proteins of interest and simultaneously observe their behavior within the complex, crowded environment of the cell.

Xie, Chong; Hanson, Lindsey; Cui, Yi; Cui, Bianxiao

2011-01-01

341

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

342

Strange Baryon to Meson Ratio  

NASA Astrophysics Data System (ADS)

We present a model to compute baryon and meson transverse momentum distributions, and their ratios, in relativistic heavy-ion collisions. The model allows to compute the probability to form colorless bound states of either two or three quarks as functions of the evolving density during the collision. The qualitative differences of the baryon to meson ratio for different collision energies and for different particle species can be associated to the different density dependent probabilities and to the combinatorial factors which in turn depend on whether the quarks forming the bound states are heavy or light. We compare to experimental data and show that we obtain a good description up to intermediate values of pt.

Cuautle, Eleazar; Ayala, Alejandro

2014-05-01

343

Rates, Ratios, Percents, and Proportions  

NSDL National Science Digital Library

Each of these sites will help you get better with percentages, rates, ratios, and solving proportions by cross-multiplying. 1. Begin by comparing fractions to decimals and to percentages. These two sites are similar. Pick one and practice it for a few minutes. Fraction-Decimal-Percent Chart or Percents-Fractions-Decimals (2) 2. Next, try to solve these percentage word problems. To find the problems, scroll down to the bottom of the page to the "Exercises." ...

Hbinggeli

2010-10-22

344

Sex ratios in bumble bees  

PubMed Central

The median proportion of investment in females among 11 populations of seven bumble bee (Bombus) species was 0.32 (range 0.07 to 0.64). By contrast, two species of workerless social parasites in the related genus Psithyrus had female-biased sex allocation, the reasons for which remain unclear. Male-biased sex allocation in Bombus contradicts the predictions of Trivers and Hare's sex ratio model for the social Hymenoptera, which are that the population sex investment ratio should be 0.5 (1:1) under queen control and 0.75 (3:1 females:males) under worker control (assuming single, once-mated, outbred queens and non-reproductive workers). Male bias in Bombus does not appear to be either an artefact, or purely the result of symbiotic sex ratio distorters. According to modifications of the Trivers–Hare model, the level of worker male-production in Bombus is insufficient to account for observed levels of male bias. There is also no evidence that male bias arises from either local resource competition (related females compete for resources) or local mate enhancement (related males cooperate in securing mates). Bulmer presented models predicting sexual selection for protandry (males are produced before females) in annual social Hymenoptera and, as a consequence (given some parameter values), male-biased sex allocation. Bumble bees fit the assumptions of Bulmer's models and are protandrous. These models therefore represent the best current explanation for the bees' male-biased sex investment ratios. This conclusion suggests that the relative timing of the production of the sexes strongly influences sex allocation in the social Hymenoptera.

Bourke, A. F. G.

1997-01-01

345

The midbrain to pons ratio  

PubMed Central

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

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

2013-01-01

346

Stable Isotope Ratios: Hurricane Olivia  

Microsoft Academic Search

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

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

2002-01-01

347

The effects of Reynolds number and Richardson number on the structure of a vertical co-flowing buoyant jet  

Microsoft Academic Search

The behavior of a vertical jet of helium issuing into a coflow of air at a fixed exit velocity ratio of 2.0 has been studied for various Reynolds numbers and Richardson numbers. It is found that the transition to turbulence is very sudden and that the point of transition moves closer to the jet exit as either the Reynolds number

E. R. Subbarao

1989-01-01

348

Extreme Low Aspect Ratio Stellarators  

NASA Astrophysics Data System (ADS)

Recently proposed Spherical Stellarator (SS) concept [1] includes the devices with stellarator features and low aspect ratio, A <= 3.5, which is very unusual for stellarators (typical stellarators have A ? 7-10 or above). Strong bootstrap current and high-? equilibria are two distinguished elements of the SS concept leading to compact, steady-state, and efficient fusion reactor. Different coil configurations advantageous for the SS have been identified and analyzed [1-6]. In this report, we will present results on novel stellarator configurations which are unusual even for the SS approach. These are the extreme-low-aspect-ratio-stellarators (ELARS), with the aspect ratio A ? 1. We succeeded in finding ELARS configurations with extremely compact, modular, and simple design compatible with significant rotational transform (? ? 0.1 - 0.15), large plasma volume, and good particle transport characteristics. [1] P.E. Moroz, Phys. Rev. Lett. 77, 651 (1996); [2] P.E. Moroz, Phys. Plasmas 3, 3055 (1996); [3] P.E. Moroz, D.B. Batchelor et al., Fusion Tech. 30, 1347 (1996); [4] P.E. Moroz, Stellarator News 48, 2 (1996); [5] P.E. Moroz, Plasma Phys. Reports 23, 502 (1997); [6] P.E. Moroz, Nucl. Fusion 37, No. 8 (1997). *Supported by DOE Grant No. DE-FG02-97ER54395.

Moroz, Paul

1997-11-01

349

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

350

39. DETAIL OF VERTICAL AT PANEL OVER PIER C, SHOWING ...  

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

39. DETAIL OF VERTICAL AT PANEL OVER PIER C, SHOWING DECK, GUARDRAIL, VERTICAL AND UPPER CHORD, VIEW TO NORTHEAST. - Blue Water Bridge, Spanning St. Clair River at I-69, I-94, & Canadian Route 402, Port Huron, St. Clair County, MI

351

40. DETAIL OF VERTICAL AT TYPICAL AT TYPICAL PANEL, SHOWING ...  

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

40. DETAIL OF VERTICAL AT TYPICAL AT TYPICAL PANEL, SHOWING DECK, GUARDRAIL, VERTICAL AND UPPER CHORD, VIEW TO NORTHEAST. - Blue Water Bridge, Spanning St. Clair River at I-69, I-94, & Canadian Route 402, Port Huron, St. Clair County, MI

352

Vertically Coupling of Resonant Cavities to Bus Waveguides.  

National Technical Information Service (NTIS)

Embodiments of the invention involve a monolithic vertical configuration for coupling a ring resonator and a bus waveguides. The monolithic vertical coupling arrangement, with the epitaxial grown coupling between the waveguide and the resonator, provides ...

C. K. Lin K. D. Djordjev M. R. T. Tan

2004-01-01

353

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

354

Magnetic coupling at vertical perovskite-spinel epitaxial interface  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

355

Aerosol particle vertical distributions and optical properties over Singapore  

NASA Astrophysics Data System (ADS)

As part of the Seven Southeast Asian Studies (7SEAS) program, an Aerosol Robotic Network (AERONET) sun photometer and a Micro-Pulse Lidar Network (MPLNET) instrument have been deployed at Singapore to study the regional aerosol environment of the Maritime Continent (MC). Using coincident AERONET Level 2.0 and MPLNET Level 2.0a data from 24 September 2009 to 31 March 2011, the seasonal variability of aerosol particle vertical distributions and optical properties is examined. On average, the bulk (˜65%) of aerosol extinction is found below 1.5 km with substantial aerosol loading (˜35%) above. Possibly due to the transition from El Niño to La Niña conditions and subsequent reduction in fire events, the MPLNET mean integrated aerosol extinction is observed to be the lowest for July-September 2010, which coincides with the typical MC biomass burning season. On the other hand, the highest mean integrated extinctions are derived for January-March 2010 and 2011, which can be attributed to off-season MC biomass burning smoke and anthropogenic pollution. The seasonal lidar ratios also show higher occurrences ?60 sr, which are indicative of biomass burning smoke, for October 2009-June 2010, but such occurrences decrease from July 2010 to March 2011 when La Niña conditions prevail. In addition, principal component analysis (PCA) identifies five primary aerosol vertical profile types over Singapore, i.e. strongly-capped/deep near-surface layer (SCD; 0-1.35 km), enhanced mid-level layer (EML; 1.35-2.4 km), enhanced upper-level layer (EUL; 2.4-3.525 km), deep contiguous layer (DCL; 3.525-4.95 km) and deep multi-layer (DML; >4.95 km). PCA also identifies an off-season MC biomass burning smoke event from 22 February to 8 March 2010, which is subsequently examined in detail.

Chew, Boon Ning; Campbell, James R.; Salinas, Santo V.; Chang, Chew Wai; Reid, Jeffrey S.; Welton, Ellsworth J.; Holben, Brent N.; Liew, Soo Chin

2013-11-01

356

Using Ratio Analysis to Evaluate Financial Performance.  

ERIC Educational Resources Information Center

The ways in which ratio analysis can help in long-range planning, budgeting, and asset management to strengthen financial performance and help avoid financial difficulties are explained. Types of ratios considered include balance sheet ratios, net operating ratios, and contribution and demand ratios. (MSE)

Minter, John; And Others

1982-01-01

357

Counter-current flow and flooding in vertical and horizontal tubes with and without obstructions  

NASA Astrophysics Data System (ADS)

This thesis presents the results of the work carried out to study counter-current flow and flooding phenonema under conditions of both vertical and vertical to horizontal flow. Two different 63.5 mm. I.D. test sections were used for this work. The first containing only a vertical leg and the second having both a vertical and a horizontal leg. For both the vertical and the horizontal test sections, it was found that for a given liquid flow rate the presence of an orifice greatly reduced the gas flow rate at which flooding occurred. Furthermore, this decrease was found to be inversely proportional to the orifice beta ratio. The experimental results, for the flooding point only, obtained in the test section containing both the vertical and the horizontal legs have been compared to the results of other researchers. In spite of the fact, that none of the test facilities used by the other researchers are identical to the one used in the present study, the results of the other researchers are in good agreement with the present results. Experiments were also carried out to study the hysteresis effect in a test section containing both a vertical and a horizontal leg. These experiments were performed both with and without various sized orifices placed in the horizontal leg. For all the cases studied, a significant hysteresis effect was observed. Two phenomenological models for the prediction of the flooding point for vertical counter-current two-phase flows are developed. The first represented flooding as being linked to the mechanism of droplet entrainment while the second related the flooding point to the mechanism of film reversal. A comparison between the predictions of these model and the experimental results obtained during the course of this investigation will be presented. A model to predict the flooding point in a test section containing vertical and horizontal legs using an extension of a model for entrainment inception applied at the crest of the hydraulic jump has been developed. The height of the hydraulic jump is calculated using methods taken from the study of open channel flows. The results of a comparison between this model and our experimental results as well as those of other researchers is presented. A review of literature in the area of counter-current gas-liquid flow has been carried out. Special emphasis is put on the phenomena that might be of relevance to the emergency core cooling during a postulated loss of coolant accident in a CANDU reactor. (Abstract shortened by UMI.)

Tye, Peter Frederick

358

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

359

Hydrodynamic Characteristics of Pile-Supported Vertical Wall Breakwaters  

Microsoft Academic Search

This paper describes the hydrodynamic characteristics of a pile-supported vertical wall breakwater, the upper part of which is a vertical wall, and the lower part consisting of an array of vertical piles. For regular waves, using the eigenfunction expansion method, a numerical model has been developed that can compute wave transmission, reflection, and run-up, and wave force acting on the

Kyung-Duck Suh; Sungwon Shin

2006-01-01

360

SideWall Vertical Electrodes for Lateral Field Microfluidic Applications  

Microsoft Academic Search

This paper describes the design, fabrication, and testing of microfluidic devices enabled by electrodes embedded vertically in the side walls of SU-8 microchannels. With vertical electrodes on the side walls, one can generate higher lateral electrical fields uniform along the vertical direction in the channel (perpendicular to the substrate). By designing the electrode shapes and configurations, uniform and nonuniform electrical

Lisen Wang; Lisa Flanagan; Abraham P. Lee

2007-01-01

361

Dissociated vertical deviation: Etiology, mechanism, and associated phenomena  

Microsoft Academic Search

Purpose: The etiology and mechanism of dissociated vertical deviation (DVD) are explored. Methods: In 6 young adults with DVD, the simultaneous horizontal, vertical, and torsional eye movements for both eyes were recorded by using dual-coil scleral search coils. Analysis of the simultaneous vertical and torsional movements that occurred during the DVD response identified the primary muscles acting in the vergences

David L. Guyton

2000-01-01

362

2-D magnetic interpretation using the vertical integral  

Microsoft Academic Search

A magnetic interpretation method is presented which numerically computes the vertical integral of the ob- served total-field anomaly along a profile. This trans- formed field is fitted by the vertical integral (also com- puted numerically) of the total-field anomaly of an interpretation model using a standard, nonlinear, least- squares estimation routine. The vertical integral trans- formation used here is similar

Joa?o B. C. Silva

1996-01-01

363

Vertical Feedthroughs for Millimeter-Wave LTCC Modules  

Microsoft Academic Search

This paper reports on novel types of vertical interconnects to be incorporated inside highly integrated LTCC Modules (Low Temperature Co-fired Ceramics). RF-transitions vertically interconnecting the top and bottom side of the LTCC are studied using alternatively CPW (coplanar waveguide) or microstrip feedlines. Vertical DC supply and control lines with integrated RF blocking capacitors are also demonstrated. LTCC test modules were

Johann Heyen; Andriy Gordiyenko; Patric Heide; Arne F. Jacob

2003-01-01

364

Vertical integration, exclusive dealing, and ex post cartelization  

Microsoft Academic Search

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

Yongmin Chen; Michael H. Riordan

2006-01-01

365

A Magnetic Suspended Self-pitch Vertical Axis Wind Generator  

Microsoft Academic Search

In this paper, basic principle and main features of a magnetic suspended self-pitch vertical axis wind turbine are presented. Compared with the horizontal axis wind turbine and the traditional vertical axis wind turbine, this new magnetic suspended self-pitch vertical axis wind turbine has the following main advantages: All permanent magnetic bearings, without friction, low start speed, low noise, high efficiency

Shuqin Liu; Zhongguo Bian; Deguang Li; Wen Zhao

2010-01-01

366

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...

367

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

368

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

369

Low-aspect ratio ignimbrites  

NASA Astrophysics Data System (ADS)

Conventionally1, three important characteristics of ignimbrites are that they show a very pronounced tendency to pond in topographic depressions, possess a flat, horizontal or gently sloping upper depositional surface, and have a thickness generally between 10 and 1,000 m. The youngest major ignimbrite, that of 1912 in the Valley of Ten Thousand Smokes (Alaska)2-4 shows these characteristics well, being ponded in a valley 25 km long with a flat upper surface sloping down-valley at an average of 1.3°, and having an estimated thickness exceeding 100 m in places. AU three characteristics are commonly used as field criteria to distinguish ignimbrites from other pyroclastic rock bodies. Here we look at certain ignimbrites which depart significantly from this conventional form in that a major part of them occurs as a thin layer mantling the landscape, resting on slopes as steep as 30°, and with an upper surface sensibly parallel with the underlying surface. We have studied two examples, the 1,800-yr-old5 Taupo ignimbrite (New Zealand), and the 1,400-yr-old Rabual ignimbrite (New Britain)6,7. We also cite several others. These ignimbrites have a remarkably low aspect ratio. This ratio, previously applied to lava extrusions8,9, provides a useful means of quantifying the overall geometry of rock bodies. The ratio is that of average thickness to lateral spread; conveniently the latter is taken as the diameter of the circle which covers the same area as the rock body.

Walker, G. P. L.; Heming, R. F.; Wilson, C. J. N.

1980-01-01

370

Low aspect ratio wing experiment  

NASA Technical Reports Server (NTRS)

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

Olsen, Mike; Seegmiller, H. Lee

1994-01-01

371

44Sc Isomeric Yield Ratios  

Microsoft Academic Search

44Sc isomeric yield ratios have been measured for the three reactions 45Sc(gamma,n)44Sc, 46Ti(gamma,np)44Sc, and 45Sc(n,2n)44Sc. Scandium oxide and titanium samples were irradiated with 48-MeV bremsstrahlung to obtain the photo-induced reactions. For the (n,2n) reaction 14-MeV neutrons were used. The yields of 44Sc in the ground and isomeric states were determined by the measurement of the residual gamma activity. A statistical-model

J. R. Tatarczuk; H. A. Medicus

1966-01-01

372

34 CFR 668.172 - Financial ratios.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Financial ratios. 668.172 Section 668.172 Education...STUDENT ASSISTANCE GENERAL PROVISIONS Financial Responsibility § 668.172 Financial ratios. (a) Appendices A and B, ratio...

2010-07-01

373

34 CFR 668.172 - Financial ratios.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Financial ratios. 668.172 Section 668.172 Education...STUDENT ASSISTANCE GENERAL PROVISIONS Financial Responsibility § 668.172 Financial ratios. (a) Appendices A and B, ratio...

2009-07-01

374

Enhancement of Condensation on a Vertical Plate  

NASA Astrophysics Data System (ADS)

In previous study, the characteristic of the condensation heat transfer on the dispersed vertical surface were investigated experimentally for the application of the finned surface to the thermoelectric generator utilizing boiling and condensation as the electrodes of the thermoelectric module. A prediction model for this diapered finned surface was proposed, based on Adamek-Webb model of the condensation on a finned tube. In this study, a condensation heat transfer experiment on a vertical dispersed finned surfaces using FC5312 was carried out, in order to enhance the condensation heat transfer coefficient by optimizing the fin size on a dispersed heat transfer surface. The object of the experiment was limited to the rectangular fin with the height of 3 mm. Experimental parameters were the temperature difference, the fin groove width, the fin thickness and the dispersing size on the vertical direction. As the results, it was found from the experiment that the dependence of the condensation heat transfer coefficient on the dispersed size is controlled by the fin groove width. That is, the condensation heat transfer coefficient will increase for a smaller fin groove width and will decrease for a larger fin groove width, with decreasing of the dispersing size. Moreover, there is an optimum fin thickness at which the condensation heat transfer coefficient becomes the maximum in the case of constant fin groove width for both size of the fin groove width. This effect of the fin thickness is more significant for the smaller fin groove width. Further, the prediction values exhibit a good agreement with the experimental data in the present experiment.

Chu, Rencai; Hatanaka, Tsutomu; Nishio, Shigefumi

375

Building FAÇADE Separation in Vertical Aerial Images  

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

376

Centropages behaviour: Swimming and vertical migration  

NASA Astrophysics Data System (ADS)

The evolutionary success of any species living in a variable environment depends on its capacity to enhance the probability of finding food and mates, and escaping predators. In the case of copepods of the genus Centropages, as in all planktonic copepods, their swimming behaviour is closely tied to these vital aspects, and shows a high degree of plasticity and adaptive capacity. Swimming mechanisms of Centropages change radically during development, mainly in the transition between naupliar stages to the 1st copepodite; nauplii do not produce feeding currents, whereas copepodites do. Adults and late developmental stages of C. typicus, C. hamatus and C. velificatus spend most of the time in slow swimming and resting breaks, with occasional and brief fast swimming (escape reactions) and grooming events. Slow swimming is closely related to the creation of feeding currents, and results from the beating of the cephalic appendages in a “fling and clap” manner. The proportion of time allocated to the different swimming activities depends on sensory cues like type and concentration of food, presence of potential mates, light intensity, hydrodynamic flow, etc. The responses of Centropages to changes in flow velocity fluctuations (small-scale turbulence) are similar to the escape responses (fast swimming) triggered by the presence of potential predators. Centropages generally have standard nocturnal vertical migration patterns involving considerable vertical displacements. This behaviour is closely related to the narrow spectral sensitivity and the low intensity threshold of the genus, and has important consequences for the active vertical transport of matter and energy. The variety of responses of Centropages to environmental changes, and in general all the aspects related to its swimming behaviour seem to be controlled by the trade-off between energetic gains (food intake), losses (swimming energy expenditure), and predation risk. Behavioural plasticity and adaptation appear to be the most relevant characteristics for the success of the genus in a wide range of marine environments.

Alcaraz, Miguel; Saiz, Enric; Calbet, Albert

2007-02-01

377

Pluto/charon Light Ratio  

NASA Astrophysics Data System (ADS)

Predicting the occultations of the stars P126 and P131.1 by Pluto on 2002 July 20 (UT) and August 21 (UT) respectively (Clancy et al. 2002 BAAS 34 1212) involved astrometric data sets spanning more than three months acquired on several telescopes. Pluto's position in these frames was determined relative to a UCAC astrometric reference network (Zacharias et al. 2000 AJ 120 2131) using a dual-source PSF model fit to the blended Pluto-Charon image. Although the final predictions were quite accurate (see http://occult.mit.edu/research/ occultations/Candidates/Predictions/P126.html and http:// occult.mit.edu/research/occultations/Candidates/Predictions/ P131.1.html) empirical corrections were made to the offset of Pluto from its ephemeris. These were based on the residuals of Pluto's measured position from its ephemeris which were sinusoidal. The consistency of the fitted residual phase and amplitude between all prediction data sets implies either an incorrect Charon to Pluto mass ratio was used in the ephemeris or that we used incorrect Pluto-Charon light ratios in this reduction. Anticipated resolved photometry of Pluto- Charon taken at Magellan should reveal the cause of these residuals. This work was funded in part by NASA grant NAG5-10444 and NSF grant AST-007 3447

Clancy, K. B.; Elliot, J. L.; Person, Mit J.

378

Experimental comparison of retrofit vertical air collectors  

SciTech Connect

Two vertical air collector systems were built and monitored. One of these is a back-pass collector in which a layer of sheet metal serves as the absorber plate. The other is a front pass collector in which the wall surface serves as the absorber plate. The results demonstrate the importance of considering heat moving through walls even when storage of heat in the wall is of limited significance. With poorly insulated walls, heat is better able to move through the wall with a front pass collector, indicating that this type of collector is a more effective heating system.

Wilson, A.T.; Stickney, B.L.

1980-01-01

379

Vertical engine for walk behind lawn mower  

SciTech Connect

This patent describes a lawn mower or other similar walk behind type of implement that is designed to be operated in a normally erect position and which is tilted to the side for servicing. An engine is provided for the lawn mower having an output shaft rotatable about a vertically extending axis. The engine includes a lubricating system incorporating a crankcase in which the engine output shaft rotates and a crankcase ventilating system. The crankcase ventilating system is designed so as to prevent lubricant from flowing into the induction system when the engine is tilted on its side.

Isaka, Y.; Oguri, K.

1988-03-01

380

Numerical modeling of vertical cavity semiconductor lasers  

SciTech Connect

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

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

1996-08-01

381

Silicon vertical microstructure fabrication by catalytic etching  

NASA Astrophysics Data System (ADS)

This study presents an effective, simple and inexpensive process for forming micro-scale vertical structures on a (1?0?0) silicon wafer. Several modified etchants and micro-patterns including rectangular, snake-like, circular and comb patterns were employed to determine the optimum etching process. We found that an etchant solution consisting of 4.6 M hydrofluoric acid, 0.44 M hydrogen peroxide and isopropyl alcohol produces microstructures at an etching rate of 0.47 µm min-1 and surface roughness of 17.4 nm. All the patterns were transferred faithfully to the silicon substrate.

Huang, Mao-Jung; Yang, Chii-Rong; Chang, Chun-Ming; Chu, Nien-Nan; Shiao, Ming-Hua

2012-08-01

382

Spirit Keeps on Trekking (vertical eye)  

NASA Technical Reports Server (NTRS)

This vertical-projection mosaic was created from navigation camera images that NASA's Mars Exploration Rover Spirit acquired on sol 121 (May 6, 2004). Continuing its trek toward the 'Columbia Hills,' Spirit drove 96.8 meters (318 feet) -- half of which was performed in auto-navigation mode -- and broke its record for the longest distance traveled in one sol. That drive brought the mission total to 1,669 meters (1.04 miles), flipping the rover's odometer over the one-mile mark.

2004-01-01

383

The NCAR Vertical Wind Tunnel: A Vertical Wind Tunnel for Controlling the Motion and Environment of Atmospheric Particles.  

National Technical Information Service (NTIS)

The NCAR vertical wind tunnel provides a vertically directed air flow that may be varied to control the vertical motion of particles, or to suspend particles for study. The environmental conditions may be varied over a range of temperature (-25 to +27 deg...

L. D. Breyfogle T. W. Cannon J. D. Sartor

1974-01-01

384

Free-flight model investigation of a vertical-attitude VTOL fighter with twin vertical tails  

NASA Technical Reports Server (NTRS)

Free-flight tests were conducted in the Langley full-scale tunnel to determine the stability and control characteristics of a vertical-attitude VTOL fighter having twin vertical tails and a pivoted fuselage forebody (nose-cockpit) arrangement. The flight tests included hovering flights and transition flights from hover to conventional forward flight. Static force tests were also made to aid in the analysis of the flight tests. The model exhibited satisfactory stability and control characteristics, and the transition from hovering flight to conventional forward flight was relatively smooth and straightforward.

Grafton, S. B.; Anglin, E. L.

1975-01-01

385

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

386

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

USGS Publications Warehouse

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

Marilyn K Murphy;Robert O'Gorman;Brent T. Boscarino;Lars G. Rudstam;June L. Eillenberger

2009-01-01

387

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

USGS Publications Warehouse

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

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

2009-01-01

388

Compartment in vertical flow reactor for ferruginous mine water  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

389

Theoretical analysis of vertical colloidal deposition  

NASA Astrophysics Data System (ADS)

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

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

2005-05-01

390

Vertical and Oblique Saccade Disconjugacy in Strabismus  

PubMed Central

Purpose. Previous studies have shown that horizontal saccades are disconjugate in humans and monkeys with strabismus. The present study was designed to extend these results to vertical and oblique saccades. A major goal was to assess the conjugacy in terms of both amplitude and direction. Methods. Saccadic eye movements were recorded binocularly in three adult monkeys. One had normal eye alignment, one had exotropia resulting from a bilateral medial rectus tenotomy in the first week of life, and one had esotropia resulting from prism rearing during the first 3 months of life. We assessed the conjugacy of saccades in various directions by comparing both amplitude and direction. Results. Saccades in the strabismic monkeys were disconjugate in terms of both amplitude and direction. These effects were as large for vertical and oblique saccades as for horizontal ones. However, the pattern of disconjugacy often varied as a function of saccade direction. In some cases, saccades that appeared to be conjugate in terms of amplitude differed substantially when direction was taken into account. Conclusions. These data indicate that the assessment of saccade disconjugacy in strabismus may yield misleading results if direction is not considered. The complex pattern of disconjugacy suggests that strabismus is associated with substantial abnormalities within the circuitry controlling saccades. Neurophysiological studies are needed to identify the specific neural substrates for these behavioral effects.

Walton, Mark M. G.; Ono, Seiji; Mustari, Michael

2014-01-01

391

High-performance vertical organic transistors.  

PubMed

Vertical organic thin-film transistors (VOTFTs) are promising devices to overcome the transconductance and cut-off frequency restrictions of horizontal organic thin-film transistors. The basic physical mechanisms of VOTFT operation, however, are not well understood and VOTFTs often require complex patterning techniques using self-assembly processes which impedes a future large-area production. In this contribution, high-performance vertical organic transistors comprising pentacene for p-type operation and C60 for n-type operation are presented. The static current-voltage behavior as well as the fundamental scaling laws of such transistors are studied, disclosing a remarkable transistor operation with a behavior limited by injection of charge carriers. The transistors are manufactured by photolithography, in contrast to other VOTFT concepts using self-assembled source electrodes. Fluorinated photoresist and solvent compounds allow for photolithographical patterning directly and strongly onto the organic materials, simplifying the fabrication protocol and making VOTFTs a prospective candidate for future high-performance applications of organic transistors. PMID:23637074

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

2013-11-11

392

Control system for a vertical axis windmill  

SciTech Connect

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/sup 0/ and 270/sup 0/ 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, R.V.

1983-10-18

393

Spaceborne Radar Measurements of Rainfall Vertical Velocity  

NASA Technical Reports Server (NTRS)

This paper studies the performance of a spaceborne precipitation radar in measuring vertical Doppler velocity of rainfall. As far as a downward pointing precipitation radar is concerned, one of the major problems affecting Doppler measurement at the nadir direction arises from the Non-Uniform Beam-Filling effect (NUBF). That is, when significant variation in rain rate is present within the radar IFOV (Instrument Field of View) in the along track direction. the Doppler shift caused by the radial component of the horizontal speed of the satellite is weighted differently among the portions of IFOV. The effects of this non-uniform weighting may dominate any other contribution. Under this condition, shape, average value and width of the Doppler spectrum may not be directly correlated with the vertical velocity of the precipitating particles. However, by using an inversion technique which over-samples the radar measurements in the along track direction, we show that the shift due to NUBF can be evaluated, and that the NUBF induced errors on average fall speed can be reduced.

Im, Eastwood; Tanelli, Simone; Giuli, Dino; Durden, Stephen L.; Facheris, Luca

2000-01-01

394

The capillary interaction between two vertical cylinders.  

PubMed

Particles floating at the surface of a liquid generally deform the liquid surface. Minimizing the energetic cost of these deformations results in an inter-particle force which is usually attractive and causes floating particles to aggregate and form surface clusters. Here we present a numerical method for determining the three-dimensional meniscus around a pair of vertical circular cylinders. This involves the numerical solution of the fully nonlinear Laplace-Young equation using a mesh-free finite difference method. Inter-particle force-separation curves for pairs of vertical cylinders are then calculated for different radii and contact angles. These results are compared with previously published asymptotic and experimental results. For large inter-particle separations and conditions such that the meniscus slope remains small everywhere, good agreement is found between all three approaches (numerical, asymptotic and experimental). This is as expected since the asymptotic results were derived using the linearized Laplace-Young equation. For steeper menisci and smaller inter-particle separations, however, the numerical simulation resolves discrepancies between existing asymptotic and experimental results, demonstrating that this discrepancy was due to the nonlinearity of the Laplace-Young equation. PMID:22738759

Cooray, Himantha; Cicuta, Pietro; Vella, Dominic

2012-07-18

395

Vertical velocity in mesoscale geophysical flows  

NASA Astrophysics Data System (ADS)

An analysis of the vertical velocity field using the full generalized {omega} equation (omega-equation) in a single mesoscale baroclinic oceanic gyre is carried out. The evolution of the gyre over 20 inertial periods is simulated using a new three-dimensional numerical model which directly integrates the horizontal ageostrophic vorticity, explicitly conserves the potential vorticity (PV) via contour advection on isopycnal surfaces, and inverts the nonlinear PV definition via the solution of a three-dimensional Monge Ampère equation. In this framework the omega-equation comes simply from the horizontal divergence of the horizontal ageostrophic vorticity prognostic equation. The ageostrophic vorticity is written as the Laplacian of a vector potential varphib, from which both the velocity and the density fields are recovered, respectively, from the curl and divergence of varphib. A new initialization technique based on the slow, progressive growth of the PV field during an initial time interval is used to avoid the generation of internal gravity waves during the initialization of the gyre. This method generates a nearly balanced baroclinic gyre for which the influence of internal gravity waves in the mesoscale vertical velocity field is negligible.

Viúdez, Álvaro; Dritschel, David G.

2003-05-01

396

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

397

Vertical Slot Convection: A linear study  

SciTech Connect

The linear stability properties of fluid convection in a vertical slot were studied. We use a Fourier-Chebychev decomposition was used to set up the linear eigenvalue problems for the Vertical Slot Convection and Benard problems. The eigenvalues, neutral stability curves, and critical point values of the Grashof number, G, and the wavenumber were determined. Plots of the real and imaginary parts of the eigenvalues as functions of G and [alpha] are given for a wide range of the Prandtl number, Pr, and special note is made of the complex mode that becomes linearly unstable above Pr [approximately] 12.5. A discussion comparing different special cases facilitates the physical understanding of the VSC equations, especially the interaction of the shear-flow and buoyancy induced physics. Making use of the real and imaginary eigenvalues and the phase properties of the eigenmodes, the eigenmodes were characterized. One finds that the mode structure becomes progressively simpler with increasing Pr, with the greatest complexity in the mid ranges where the terms in the heat equation are of roughly the same size.

McAllister, A. (Tokyo Univ. (Japan)); Steinolfson, R. (Southwest Research Inst., San Antonio, TX (United States)); Tajima, T. (Texas Univ., Austin, TX (United States). Inst. for Fusion Studies)

1992-11-01

398

Vertical Slot Convection: A linear study  

SciTech Connect

The linear stability properties of fluid convection in a vertical slot were studied. We use a Fourier-Chebychev decomposition was used to set up the linear eigenvalue problems for the Vertical Slot Convection and Benard problems. The eigenvalues, neutral stability curves, and critical point values of the Grashof number, G, and the wavenumber were determined. Plots of the real and imaginary parts of the eigenvalues as functions of G and {alpha} are given for a wide range of the Prandtl number, Pr, and special note is made of the complex mode that becomes linearly unstable above Pr {approximately} 12.5. A discussion comparing different special cases facilitates the physical understanding of the VSC equations, especially the interaction of the shear-flow and buoyancy induced physics. Making use of the real and imaginary eigenvalues and the phase properties of the eigenmodes, the eigenmodes were characterized. One finds that the mode structure becomes progressively simpler with increasing Pr, with the greatest complexity in the mid ranges where the terms in the heat equation are of roughly the same size.

McAllister, A. [Tokyo Univ. (Japan); Steinolfson, R. [Southwest Research Inst., San Antonio, TX (United States); Tajima, T. [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies

1992-11-01

399

Enhancement of Condensation on a Vertical Plate  

NASA Astrophysics Data System (ADS)

In previous study, the characteristic of the condensation heat transfer on the dispersed vertical surface were investigated experimentally for the application of the finned surface to the thermoelectric generator utilizing boiling and condensation as the electrodes of the thermoelectric module. A prediction model for this diapered finned surface was proposed, based on Adamek-Webb model of the condensation on a finned tube. In this study, a condensation heat transfer experiment on a vertical dispersed finned surfaces using FC5312 was carried out, in order to enhance the condensation heat transfer coefficient by optimizing the fin size on a dispersed heat transfer surface. Experimental parameters were the fin width, thickness, height and the dispersed fin length. As the results, it was found from the experiment there was a dispersed fin length corresponding to the condensation at the maximum and its value was 1.75 mm. As the characteristic, the condensation changed from slowly increasing to rapidly increasing and then decreasing at a steep grade, with decreasing the dispersed fin length. In addition, the fin height did not affect this optimum dispersed fin length and the dispersed fin length affects the dependence of the condensation on different fin thickness. Further, the prediction values have a good agreement with the experimental data except the case of short dispersed fin length.

Chu, Rencai; Hatanaka, Tsutomu; Nishio, Shigefumi

400

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

401

Reconstructing bulk isotope ratios from compound-specific isotope ratios.  

PubMed

Carbon isotope analysis by bulk elemental analysis coupled with isotope ratio mass spectrometry has been the mainstay of delta(13)C analyses both at natural abundance and in tracer studies. More recently, compound-specific isotope analysis (CSIA) has become established, whereby organic constituents are separated online by gas or liquid chromatography before oxidation and analysis of CO(2) for constituent delta(13)C. Theoretically, there should be concordance between bulk delta(13)C measurements and carbon-weighted delta(13)C measurements of carbon-containing constituents. To test the concordance between the bulk and CSIA, fish oil was chosen because the majority of carbon in fish oil is in the triacylglycerol form and approximately 95% of this carbon is amenable to CSIA in the form of fatty acids. Bulk isotope analysis was carried out on aliquots of oil extracted from 55 fish samples and delta(13)C values were obtained. Free fatty acids (FFAs) were produced from the oil samples by saponification and derivatised to fatty acid methyl esters (FAMEs) for CSIA by gas chromatography/combustion/isotope ratio mass spectrometry. A known amount of an internal standard (C15:0 FAME) was added to allow analyte quantitation. This internal standard was also isotopically calibrated in both its FFA (delta(13)C = -34.30 per thousand) and FAME (delta(13)C = -34.94 per thousand) form. This allowed reporting of FFA delta(13)C from measured FAME delta(13)C values. The bulk delta(13)C was reconstructed from CSIA data based on each FFA delta(13)C and the relative amount of CO(2) produced by each analyte. The measured bulk mean delta(13)C (SD) was -23.75 per thousand (1.57 per thousand) compared with the reconstructed bulk mean delta(13)C of -23.76 (1.44 per thousand) from CSIA and was not significantly different. Further analysis of the data by the Bland-Altman method did not show particular bias in the data relative to the magnitude of the measurement. Good agreement between the methods was observed with the mean difference between methods (range) of 0.01 per thousand (-1.50 to 1.30). PMID:20499325

Morrison, Douglas J; Cooper, Karen; Preston, Tom

2010-06-30

402

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

403

Advanced high area ratio nozzles  

NASA Technical Reports Server (NTRS)

The objective is to develop computational techniques for the design of high-area-ratio nozzles and to validate these models by comparison with experiments and computations using other codes. Progress was made in two areas during the past year. First, performance computations were added to the PARC2D code and the performance of the SSME nozzle was computed for inviscid, laminar and turbulent flow assuming a perfect gas with gamma = 1.2. Second, the PARC2D code was modified in a non-CASP project to compute equilibrium flow about hypersonic blunt bodies. Progress has been made toward modifying this code to compute equilibrium H2/O2 flow through the SSME and related nozzles.

Raiszadeh, Farhad; Collins, Frank G.; Orr, Joseph L., Jr.; Myruski, Brian

1995-01-01

404

Advanced high area ratio nozzles  

NASA Technical Reports Server (NTRS)

The objective is to develop computational techniques for the design of high-area-ratio nozzles and to validate these models by comparison with experiments and computations using other codes. Performance computations were added to the PARC2D code and the performance of the space shuttle main engine (SSME) nozzle was computed for inviscid, laminar and turbulent flow assuming a perfect gas with gamma = 1.2. The PARC2D code was modified in a non-CASP (Center for Advanced Space Propulsion) project to compute equilibrium flow about hypersonic blunt bodies. Progress has been made toward modifying this code to compute equilibrium H2/O2 flow through the SSME and related nozzles.

Raiszadeh, Farhad; Collins, Frank G.; Orr, Joseph L., Jr.; Myruski, Brian

1989-01-01

405

Beaded Braids: Investigating Patterns & Ratios  

NSDL National Science Digital Library

In this activity learners create patterns of hair beads. Simone and Brianna like different mixes of beads in their braids, so learners must figure out how to distribute 40 beads to satisfy both characters. Images of the two girls are provided in the PDF. Either 20 each of two types of real beads can be used, or the learner can cut out paper beads (20 round and 20 heart-shaped), though the pattern is missing from the PDF. Included questions help learners explore ratio through addition, multiplication, and division. Learners can color the pictures and beads, and make braids with yarn for fun. This activity could also be adapted in terms of decorating lanyard and would connect very well with afterschool or home craft activities.

Science, Lawrence H.

2003-01-01

406

Fluid flow through a vertical to horizontal 90 elbow bend III three phase flow  

SciTech Connect

Three phase water/oil/air flow was studied around a vertical upward to horizontal 90 elbow bend of R/d = 0.654. The results were more complex than corresponding two phase data. The pressure drop recorded for the two tangent legs sometimes showed significant variations to the straight pipe data. In most cases this variation was caused by differences in the flow regimes between the two systems. The elbow bend tended to constrict the flow presented by the vertical inlet tangent leg while sometimes acting as a wave and droplet generator for the horizontal outlet tangent leg. It could be argued that the inclusion of the elbow bend altered the flow regime map transitional boundaries but it also is possible that insufficient settling length was provided in the apparatus design. The elbow bend pressure drop was best presented as l{sub e}/d the equivalent length to diameter ratio using the actual total pressure drop in the vertical inlet tangent leg. Generally l{sub e}/d values rose with gas rate, but exhibited an increasingly complex relation with f{sub o} the oil to liquid volumetric ratio as liquid rate was increased. A significant maximum in l{sub e}/d was in evidence around the inversion from water dominated to oil dominated flows. Several models are presented to predict the data. (author)

Spedding, P.L.; Benard, E.; Crawford, N.M. [School of Mechanical and Aerospace Engineering, Queen's University Belfast, Ashby Building, Belfast BT9 5AH (United Kingdom)

2008-01-15

407

Weather-Corrected Performance Ratio  

SciTech Connect

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

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

2013-04-01

408

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

409

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

PubMed Central

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

2014-01-01

410

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

411

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

412

Feasibility study of a passive aeration reactor equipped with vertical pipes for compost stabilization of cow manure.  

PubMed

Pilot-scale composting was carried out with cow manure to evaluate the performances of two passive aeration systems: a conventional passive aeration system equipped with horizontal pipes and an unusual passive aeration method based on air delivery by means of vertical pipes. The effects of both types of passive aeration apparatus were investigated in order to determine the degree of composting rate by continuously monitoring temperature, moisture content, organic matter, electrical conductivity, pH and C/N ratio in the piles. Temperatures in the range of thermophily (55-65 degrees C) were reached in all runs within 1-2 days then lasting for about 1 week, a span long enough for pathogen abatement. Results suggest that passive aeration carried out by vertical pipes is more effective for air delivery into compost piles than conventional passive aeration of air adduction with horizontal pipes. The variation in the number of vertical pipes was revealed to be an important parameter for the control of composting rate and temperature. Composting rates estimated from the heat balance equation were substantially in agreement with those computed through the conversion ratio of total organic matter decrement. The conversion ratios and composting rates obtained in this study using passive aeration with vertical pipes were well aligned with those found using forced air delivery systems. PMID:17121117

Sylla, Youssouf Boundou; Kuroda, Masao; Yamada, Masayuki; Matsumoto, Naoko

2006-10-01

413

Vertical cavity surface emitting lasers emitting near 1.5 {mu}m with Sb-based reflectors  

SciTech Connect

We describe use of AlAsSb/AlGaAsSb lattice matched to InP for distributed Bragg reflectors. These structures are integral to several surface normal devices, in particular vertical cavity surface emitting lasers. The high refractive index ratio of these materials allows formation of a highly reflective mirror with relatively few mirror pairs. As a result, we have been able to show for the first time the 77K CW operation of an optically pumped, monolithic, all-epitaxial vertical cavity laser, emitting at 1.56 {mu}m.

Blum, O.; Klem, J.F.; Vawter, G.A. [and others

1998-04-01

414

Noise of the Harrier in vertical landing and takeoff  

NASA Technical Reports Server (NTRS)

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

Soderman, Paul T.; Foster, John D.

1988-01-01

415

Computational study of graphene-based vertical field effect transistor  

NASA Astrophysics Data System (ADS)

Poisson and drift-diffusion equations are solved in a three-dimensional device structure to simulate graphene-based vertical field effect transistors (GVFETs). Operation mechanisms of the GVFET with and without punched holes in the graphene source contact are presented and compared. The graphene-channel Schottky barrier can be modulated by gate electric field due to graphene's low density of states. For the graphene contact with punched holes, the contact barrier thinning and lowering around punched hole edge allow orders of magnitude higher tunneling current compared to the region away from the punched hole edge, which is responsible for significant performance improvement as already verified by experiments. Small hole size is preferred due to less electrostatic screening from channel inversion layer, which gives large electric field around the punched hole edge, thus, leading to a thinner and lower barrier. Bilayer and trilayer graphenes as the source contact degrade the performance improvement because stronger electrostatic screening leads to smaller contact barrier lowering and thinning. High punched hole area percentage improves current performance by allowing more gate electric field to modulate the graphene-channel barrier. Low effective mass channel material gives better on-off current ratio.

Chen, Wenchao; Rinzler, Andrew; Guo, Jing

2013-03-01

416

Numerical study of multicellular natural convection in vertical cavities  

NASA Astrophysics Data System (ADS)

The structure of the multicellular convection resulting from the hydrodynamic instability of a flow in both a tall vertical rectangular and a tall annular cavity was calculated by finite difference methods. The effects on the flow structure and the average Nusselt number of varying the Prandtl number of the fluid, the aspect ratio of the cavity and the Grashof number were studied. How the curvature of the walls influences the flow patterns in an annulus was also studied. In addition to predicting the right multicellular flow structure at low Prandtl numbers in a rectangular cavity, travelling wave solutions were obtained for water. The results for the flow of a low Prandtl number fluid in an annulus show a multicellular flow structure which drifts upward with a speed which compares well with the experimentally observed value. The heat transfer results for air in tall rectangular cavities have application to double glazed windows and provide a guide to establishing the proper gap width for best insulation.

Lee, Y.

417

Natural convection heat transfer from vertical parallel plates to air  

NASA Astrophysics Data System (ADS)

Two-dimensional Navier-Stokes and energy equations are numerically solved for laminar natural convection of air between vertical parallel plane plates with uniform heat flux. Calculations are carried out under the conditions of the modified Grashof number (2.3 x 10(exp 3) less than or equals to Gr(sup *) less than or equals to 8.8 x 10(exp 5)) and height to plate spacing ratio (8 less than or equals to l/h less than or equals to 30), which covers the practical range encountered with the air cooling system of electronic equipment. The numerical solutions are compared with present experimental results. The local Nusselt numbers and induced flow rates obtained numerically agree well with those measured. A correlation expression for the local Nusselt number is proposed which can predict the local plate temperature within 5 percent error. When the value of dimensionless variable Phi = ((h/x)Gr(sup *)Pr)/((h/l)Gr(sup *)Pr) is greater than approximately 10(exp 2). The existing results based on the boundary layer approximation are found to be not applicable for predicting the maximum plate temperature.

Fujii, Motoo; Gima, Satoru; Tomimura, Toshio; Zhang, Xing

1993-09-01

418

Edge technique Doppler lidar wind measurements with high vertical resolution.  

PubMed

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

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

1997-08-20

419

Seismic velocities and Poisson's ratio of shallow unconsolidated sands  

SciTech Connect

The authors determined P- and S-wave velocity depth profiles in shallow, unconsolidated beach sand by analyzing three-component surface seismic data. P- and S-wave velocity profiles were calculated from travel time measurements of vertical and tangential component seismograms, respectively. The results reveal two discrepancies between theory and data. Whereas both velocities were found to be proportional to the pressure raised to the power of 1/6, as predicted by the Hertz-Mindlin contact theory, the actual values of the velocities are less than half of those calculated from this theory. The authors attribute this discrepancy to the angularity of the sand grains. Assuming that the average radii of curvature at the grain contacts are smaller than the average radii of the grains, they modify the Hertz-Hindlin theory accordingly. They found that the ratio of the contact radius to the grain radius is about 0.086. The second disparity is between the observed Poisson's ratio of 0.15 and the theoretical value (0.008 for random pack of quartz spheres). This discrepancy can be reconciled by assuming slip at the grain contacts. Because slip decreases the shearing between grains, Poisson's ratio increases.

Bachrach, R.; Dvorkin, J.; Nur, A.M.

2000-04-01

420

Combining horizontal ambient vibration components for H/V spectral ratio estimates  

NASA Astrophysics Data System (ADS)

In the current literature, several procedures for computing average horizontal to vertical (H/V) spectral ratio of ambient vibrations are interchangeably adopted, whose possible equivalence has never been checked. To this purpose, expected sampling properties of average H/V spectral ratio relative to commonly adopted procedures are determined in the frame of a coherent physical-statistical model. This analysis reveals that all the considered estimators provide H/V estimates that are biased of amounts ranging from 46 per cent up to above 100 per cent of the true value. The amount of these biases is not reduced when H/V spectral ratio estimates are determined, as in the common practice, by averaging H/V spectral ratios computed over a number of time-windows extracted from the experimental record. On the other hand, these biases can be drastically reduced in the case that H/V spectral ratio is computed as the squared root of the ratio of horizontal (whatever the north/south-east/west combination procedure is) and vertical ground motion spectral powers, each separately computed from a large (tens or more) set of non-overlapping time-windows extracted from the original record. The role of smoothing procedures in the frequency domain is also sketched, obtaining an indication that they can contribute to drop these biases. An experimental example showing the presence of these biases and the different effectiveness of the processing procedures is also shown.

Albarello, Dario; Lunedei, Enrico

2013-08-01

421

Nitrogen to argon ratio in volcanic gases  

Microsoft Academic Search

A study is made of N2\\/Ar ratios in volcanic gases in order to evaluate the factors influencing such ratios. Particular attention is given to N2 derived from sedimentary material as it influences the N2\\/Ar ratio of volcanic gases. Gases derived from the deeper mantle of the earth are also examined for N2\\/Ar ratios. The N2\\/Ar ratios of volcanic gases show

S. Matsuo; M. Suzuki; Y. Mizutani

1978-01-01

422

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

423

Economies of scale and vertical integration in the investor-owed electric utility industry  

SciTech Connect

This report analyzes the nature of costs in a vertically integrated electric utility. Findings provide new insights into the operations of the vertically integrated electric utility and supports earlier research on economics of scale and density; results also provide insights for policy makers dealing with electric industry restructuring issues such as competitive structure and mergers. Overall, results indicate that for most firms in the industry, average costs would not be reduced through expansion of generation, numbers of customers, or the delivery system. Evidently, the combination of benefits from large-scale technologies, managerial experience, coordination, or load diversity have been exhausted by the larger firms in the industry; however many firms would benefit from reducing their generation-to-sales ratio and by increasing sales to their existing customer base. Three cost models were used in the analysis.

Thompson, H.G. [Christensen Associates, Madison, WI (United States); Islam, M.; Rose, K.

1996-01-01

424

Crystal Ice Formation of Solution and Its Removal Phenomena around Vertical Cooled Cylinder  

NASA Astrophysics Data System (ADS)

Experimental and analytical studies for freezing phenomena of ethylene glycol solution around a vertical cooled polyvinyl-chloride cylinder have been performed. It is found that the crystal ice formed around the vertical cylinder is removed from the cylinder surface due to buoyancy force acting on the crystal ice. The crystal ice slides along the cylinder surface due to buoyancy force and grows in a shape of tube by joining with the neighbour ice. It is shown that the onset of ice removal condition is related to the heat flux at the cylinder surface when the latent heat of fusion is discharged with freezing, and that the heat flux ratio of 'from the cylinder surface into the cylinder' to 'from the cylinder surface to the solution' is an important parameter for the onset conditions. The ice removal occurs easily for short cylinders than for long ones.

Hirata, Tetsuo; Ishikawa, Masaaki; Akutsu, Nobuaki

425

Electronic transport in individual, vertical, catalyst free GaN/AlN nanowires  

NASA Astrophysics Data System (ADS)

In the recent years, the advances in the THz technology, for example the development of the quantum cascade laser, promotes the possibility to use resonant tunneling diodes (RTD) to enhance such technologies. Coaxial m-plane AlN/GaN nanowire based resonant tunneling diode structures were formed by plasma assisted molecular beam epitaxy (MBE) using a two-step growth method that allows for control of vertical and lateral growth [1]. They are spontaneously formed MBE nanowires and they are integrated in Si (111). We discuss ongoing work on the electronic transport in these individual, vertical nanowires using two nanoprobes to contact the top of the nanowire and the substrate. The IV characteristics reveal a clear negative differential resistance (NDR) at room temperature (RT). The NDR was observed ˜ 4V with a peak-to-valley ratio as high as 10. [1] S.D. Carnevale et al., Nano Letters, 11, (2), 2011.

Marginean, Camelia; Carnevale, Santino; Phillips, Patrick; Kent, Thomas; Pelekhov, Denis; Mills, Michael; Myers, Roberto

2012-02-01

426

Deep and vertical silicon bulk micromachining using metal assisted chemical etching  

NASA Astrophysics Data System (ADS)

In this paper, a newfound and simple silicon bulk micromachining process based on metal-assisted chemical etching (MaCE) is proposed which opens a whole new field of research in MEMS technology. This method is anisotropic and by controlling the etching parameters, deep vertical etching, relative to substrate surface, can be achieved in micrometer size for <1?0?0> oriented Si wafer. By utilizing gold as a catalyst and a photoresist layer as the single mask layer for etching, 60 µm deep gyroscope micromachined structures have been fabricated for 2 µm features. The results indicate that MaCE could be the only wet etching method comparable to conventional dry etching recipes in terms of achievable etch rate, aspect ratio, verticality and side wall roughness. It also does not need a vacuum chamber and the other costly instruments associated with dry etching techniques.

Zahedinejad, Mohammad; Delaram Farimani, Saeed; Khaje, Mahdi; Mehrara, Hamed; Erfanian, Alireza; Zeinali, Firooz

2013-05-01

427

Global observation of vertical-CLVD earthquakes at active volcanoes  

NASA Astrophysics Data System (ADS)

AbstractSome of the largest and most anomalous volcanic earthquakes have non-double-couple focal mechanisms. Here, we investigate the link between volcanic unrest and the occurrence of non-double-couple earthquakes with dominant <span class="hlt">vertical</span> tension or pressure axes, known as <span class="hlt">vertical</span> compensated-linear-vector-dipole (<span class="hlt">vertical</span>-CLVD) earthquakes. We determine focal mechanisms for 313 target earthquakes from the standard and surface wave catalogs of the Global Centroid Moment Tensor Project and identify 86 shallow 4.3 ? MW ? 5.8 <span class="hlt">vertical</span>-CLVD earthquakes located near volcanoes that have erupted in the last ~100 years. The majority of <span class="hlt">vertical</span>-CLVD earthquakes occur in subduction zones in association with basaltic-to-andesitic stratovolcanoes or submarine volcanoes, although <span class="hlt">vertical</span>-CLVD earthquakes are also located in continental rifts and in regions of hot spot volcanism. <span class="hlt">Vertical</span>-CLVD earthquakes are associated with many types of confirmed or suspected eruptive activity at nearby volcanoes, including volcanic earthquake swarms as well as effusive and explosive eruptions and caldera collapse. Approximately 70% of all <span class="hlt">vertical</span>-CLVD earthquakes studied occur during episodes of documented volcanic unrest at a nearby volcano. Given that volcanic unrest is underreported, most shallow <span class="hlt">vertical</span>-CLVD earthquakes near active volcanoes are likely related to magma migration or eruption processes. <span class="hlt">Vertical</span>-CLVD earthquakes with dominant <span class="hlt">vertical</span> pressure axes generally occur after volcanic eruptions, whereas <span class="hlt">vertical</span>-CLVD earthquakes with dominant <span class="hlt">vertical</span> tension axes generally occur before the start of volcanic unrest. The occurrence of these events may be useful for identifying volcanoes that have recently erupted and those that are likely to erupt in the future.</p> <div class="credits"> <p class="dwt_author">Shuler, Ashley; Nettles, Meredith; EkströM, GöRan</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">428</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.G41C..03S"> <span id="translatedtitle"><span class="hlt">Vertical</span> GPS ground motion rates in the Euro-Mediterranean region: new evidence of <span class="hlt">vertical</span> velocity gradients at different spatial scales along the Nubia-Eurasia plate boundary</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We use 2.5 to 14 years long position time-series from ~1000 continuous GPS stations to study <span class="hlt">vertical</span> ground motions in the Euro-Mediterranean region and provide a first synoptic view of the <span class="hlt">vertical</span> velocity field along the broad Nubia-Eurasia plate boundary. By estimating and removing common mode errors in position time-series from the results of a principal component analysis, we obtain a significant gain in the signal-to-noise <span class="hlt">ratio</span> of the displacements data. Following the results of a maximum likelihood estimation analysis, which gives a mean spectral index ~-0.7, we adopt a power-law + white noise stochastic model in estimating the final <span class="hlt">vertical</span> rates, and find 95% of the velocities within ×2 mm/yr in the study area, with uncertainties from filtered time-series ~40% smaller than from the unfiltered ones. We evaluate the contribute of the glacial isostatic adjustment (GIA) signal to the <span class="hlt">vertical</span> velocity budget using two different global models, characterized by distinct rheological layering of the Earth's mantle and different descriptions of the time-history of the mass of continental ice sheets since the Last Glacial Maximum. The analysis carried out allows us to highlight, for the first time, the presence of statistically significant, and spatially coherent, velocity gradients where a higher density of stations is available. We find undulations of the <span class="hlt">vertical</span> velocity field occurring at different spatial scales both in regions characterized by tectonic activity, like eastern Alps, Apennines and eastern Mediterranean, and regions characterized by low to null tectonic activity, like central Iberia and western Alps. Correcting the observed velocities for GIA, although the two models used predict different GIA velocities and patterns, doesn't change significantly the velocity gradients. A correlation between smooth <span class="hlt">vertical</span> velocities and topographic features is apparent in many sectors of the study area. GIA and weathering processes cannot completely explain the measured rates, and a combination of active tectonics and deep-seated geodynamic processes must be used to explain our observations. Excluding areas where more localized processes are likely, or where subduction/delamination processes may be active, mantle dynamics is the most likely process, but regional mantle modeling is required for a better understanding.</p> <div class="credits"> <p class="dwt_author">Serpelloni, E.; Faccenna, C.; Spada, G.; Dong, D.; Williams, S. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">429</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20030111420&hterms=longitudinal+river+profiles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlongitudinal%2Briver%2Bprofiles"> <span id="translatedtitle"><span class="hlt">Vertical</span> Analysis of Martian Drainage Basins</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We have performed a <span class="hlt">vertical</span> analysis of drainage basins on Mars that were computationally extracted from DEMs based on the MOLA data. Longitudinal profiles of main streams are calculated and the slope-area relation is established for 20 basins coming from assorted martian locations. An identical analysis is done for 19 terrestrial river basins. Our results show that, in comparison to terrestrial basins, martian basins have more linear longitudinal profiles, more frequent existence of knickpoints, predominance of asymmetric location of the main stream in the basin, and smaller values of concavity exponent. This suggests a limited role for surface runoff on the global scale. However, two basins extracted from the slopes of martian volcanoes show a strong similarity to terrestrial basins, indicating a possible local role for the process of surface runoff.</p> <div class="credits"> <p class="dwt_author">Stepinski, T. F.; OHara, W. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">430</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22639830"> <span id="translatedtitle"><span class="hlt">Vertically</span> aligned BCN nanotubes with high capacitance.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Using a chemical vapor deposition method, we have synthesized <span class="hlt">vertically</span> aligned BCN nanotubes (VA-BCNs) on a Ni-Fe-coated SiO(2)/Si substrate from a melamine diborate precursor. The effects of pyrolysis conditions on the morphology and thermal property of grown nanotubes, as well as the nanostructure and composition of an individual BCN nanotube, were systematically studied. It was found that nitrogen atoms are bonded to carbons in both graphitic and pyridinic forms and that the resultant VA-BCNs grown at 1000 °C show the highest specific capacitance (321.0 F/g) with an excellent rate capability and high durability with respect to nonaligned BCN (167.3 F/g) and undoped multiwalled carbon nanotubes (117.3 F/g) due to synergetic effects arising from the combined co-doping of B and N in CNTs and the well-aligned nanotube structure. PMID:22639830</p> <div class="credits"> <p class="dwt_author">Iyyamperumal, Eswaramoorthi; Wang, Shuangyin; Dai, Liming</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-26</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">431</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3746203"> <span id="translatedtitle">Multispectral imaging with <span class="hlt">vertical</span> silicon nanowires</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">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 <span class="hlt">vertical</span> 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.</p> <div class="credits"> <p class="dwt_author">Park, Hyunsung; Crozier, Kenneth B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">432</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMOS13D1766A"> <span id="translatedtitle">Development of <span class="hlt">Vertical</span> Cable Seismic System (2)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">vertical</span> cable seismic is one of the reflection seismic methods. It uses hydrophone arrays <span class="hlt">vertically</span> moored from the seafloor to record acoustic waves generated by surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. This type of survey is generally called VCS (<span class="hlt">Vertical</span> Cable Seismic). Because VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed the method for the hydrothermal deposit survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We are now developing a VCS system, including not only data acquisition hardware but data processing and analysis technique. Our first experiment of VCS surveys has been carried out in Lake Biwa, JAPAN in November 2009 for a feasibility study. Prestack depth migration is applied to the 3D VCS data to obtain a high quality 3D depth volume. Based on the results from the feasibility study, we have developed two autonomous recording VCS systems. After we carried out a trial experiment in the actual ocean at a water depth of about 400m and we carried out the second VCS survey at Iheya Knoll with a deep-towed source. In this survey, we could establish the procedures for the deployment/recovery of the system and could examine the locations and the fluctuations of the <span class="hlt">vertical</span> cables at a water depth of around 1000m. The acquired VCS data clearly shows the reflections from the sub-seafloor. Through the experiment, we could confirm that our VCS system works well even in the severe circumstances around the locations of seafloor hydrothermal deposits. We have carried out two field surveys in 2011. One is a 3D survey with a boomer for a high-resolution surface source and the other one for an actual field survey in the Izena Cauldron an active hydrothermal area in the Okinawa Trough. Through these surveys, we have confirmed that the uncertainty in the locations of the source and of the hydrophones in water could lower the quality of subsurface image. It is, therefore, strongly necessary to develop a total survey system that assures an accurate positioning and a deployment techniques. In case of shooting on sea surface, GPS navigation system are available, but in case of deep-towed source or ocean bottom source, the accuracy of shot position with SSBL/USBL is not sufficient for the very high-resolution imaging as requested for the SMS survey. We will incorporate the accurate LBL navigation systems with VCs. The LBL navigation system has been developed by IIS of the University of Tokyo. The error is estimated less than 10cm at the water depth of 3000m. Another approach is that the shot points can be calculated using the first break of the VCS after the VCS locations are estimated by slant-ranging from the sea surface. Our VCS system has been designed as a survey tool for hydrothermal deposit, but it will be also applicable for deep water site surveys or geohazard assessment such as active faults.</p> <div class="credits"> <p class="dwt_author">Asakawa, E.; Murakami, F.; Tsukahara, H.; Ishikawa, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">433</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/11343103"> <span id="translatedtitle">Oceanography. <span class="hlt">Vertical</span> mixing in the ocean.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">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 <span class="hlt">vertical</span> 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</p> <div class="credits"> <p class="dwt_author">Webb, D J; Suginohara, N</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">434</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6050124"> <span id="translatedtitle"><span class="hlt">Vertical</span> axis wind turbine control strategy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Early expensive in automatic operation of the Sandia 17-m <span class="hlt">vertical</span> 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.</p> <div class="credits"> <p class="dwt_author">McNerney, G.M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">435</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA11840&hterms=drive&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddrive"> <span id="translatedtitle">Opportunity's Surroundings After Sol 1820 Drive (<span class="hlt">Vertical</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009). <p/> This view is presented as a <span class="hlt">vertical</span> projection with geometric seam correction. North is at the top. <p/> The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). <p/> The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">436</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012JAP...111d4507F"> <span id="translatedtitle">Bidirectional operation of <span class="hlt">vertical</span> organic triodes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Due to their effective short channel length of only a few hundred nanometers, <span class="hlt">vertical</span> organic triodes (VOTs) have a high potential to overcome problems of low current densities and switching speed in current organic field effect transistors (OFETs). Furthermore, VOTs are easy to build because no sub-structuring of the base contact is necessary. Nevertheless, these devices are poorly investigated. In literature, two different working mechanisms are suggested: hot carrier transport through the metallic base or transport of charge carriers through a permeable base electrode. As a strong asymmetry is expected for function principle based on hot carriers, we are able to distinguish between both mechanisms by examining the bidirectional transmission properties of the VOT consisting of electron transporting materials. We show that high transmission values (>95%) are possible for both directions, suggesting a base contact with openings forming a grid electrode.</p> <div class="credits"> <p class="dwt_author">Fischer, Axel; Siebeneicher, Philipp; Kleemann, Hans; Leo, Karl; Lüssem, Björn</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">437</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6465272"> <span id="translatedtitle">Some aspects of fluctuating <span class="hlt">vertical</span> wind shears</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Fluctuating <span class="hlt">vertical</span> 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.</p> <div class="credits"> <p class="dwt_author">Doran, J.C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">438</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6669127"> <span id="translatedtitle">Dynamic soil pressures on rigid <span class="hlt">vertical</span> walls</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A critical evaluation is made of the dynamic pressures and the associated forces induced by ground shaking on a rigid, straight, <span class="hlt">vertical</span> 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.</p> <div class="credits"> <p class="dwt_author">Veletsos, A.S.; Younan, A.H. (Rice Univ., Houston, TX (United States))</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">439</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3596098"> <span id="translatedtitle">Functionalization of <span class="hlt">vertically</span> aligned carbon nanotubes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Summary This review focuses and summarizes recent studies on the functionalization of carbon nanotubes oriented perpendicularly to their substrate, so-called <span class="hlt">vertically</span> aligned carbon nanotubes (VA-CNTs). The intrinsic properties of individual nanotubes make the VA-CNTs ideal candidates for integration in a wide range of devices, and many potential applications have been envisaged. These applications can benefit from the unidirectional alignment of the nanotubes, the large surface area, the high carbon purity, the outstanding electrical conductivity, and the uniformly long length. However, practical uses of VA-CNTs are limited by their surface characteristics, which must be often modified in order to meet the specificity of each particular application. The proposed approaches are based on the chemical modifications of the surface by functionalization (grafting of functional chemical groups, decoration with metal particles or wrapping of polymers) to bring new properties or to improve the interactions between the VA-CNTs and their environment while maintaining the alignment of CNTs.</p> <div class="credits"> <p class="dwt_author">Snyders, Rony; Colomer, Jean-Francois</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">440</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA07078&hterms=drag&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddrag"> <span id="translatedtitle">Track of Right-Wheel Drag (<span class="hlt">Vertical</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> 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 <span class="hlt">vertical</span> projection with geometric seam correction.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_21");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">441</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16319831"> <span id="translatedtitle">The <span class="hlt">vertical</span> profile of winds on Titan.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">One of Titan's most intriguing attributes is its copious but featureless atmosphere. The Voyager 1 fly-by and occultation in 1980 provided the first radial survey of Titan's atmospheric pressure and temperature and evidence for the presence of strong zonal winds. It was realized that the motion of an atmospheric probe could be used to study the winds, which led to the inclusion of the Doppler Wind Experiment on the Huygens probe. Here we report a high resolution <span class="hlt">vertical</span> profile of Titan's winds, with an estimated accuracy of better than 1 m s(-1). The zonal winds were prograde during most of the atmospheric descent, providing in situ confirmation of superrotation on Titan. A layer with surprisingly slow wind, where the velocity decreased to near zero, was detected at altitudes between 60 and 100 km. Generally weak winds (approximately 1 m s(-1)) were seen in the lowest 5 km of descent. PMID:16319831</p> <div class="credits"> <p class="dwt_author">Bird, M K; Allison, M; Asmar, S W; Atkinson, D H; Avruch, I M; Dutta-Roy, R; Dzierma, Y; Edenhofer, P; Folkner, W M; Gurvits, L I; Johnston, D V; Plettemeier, D; Pogrebenko, S V; Preston, R A; Tyler, G L</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">442</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004JAtS...61.1859W"> <span id="translatedtitle">Tropical Cyclone Intensity in <span class="hlt">Vertical</span> Wind Shear.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The structure and intensity changes of tropical cyclones (TCs) in environmental <span class="hlt">vertical</span> wind shear (VWS) are investigated in this study using the fifth-generation Pennsylvania State University National Center for Atmospheric Research (PSU NCAR) Mesoscale Model (MM5). Triply nested domains of 36-, 12-, and 4-km resolution are used with fully explicit moisture physics in the 4-km domain. Idealized environments with easterly shears of 2, 4, 6, 8, and 10 m s-1 between 800 and 200 hPa are applied on an f plane. Under small values of VWS (2 and 4 m s-1), the TC intensities are similar to that of the control (CTRL; i.e., no VWS) after initial adjustments. The TCs under 6 and 8 m s-1 of VWS are not as intense, although they do not weaken during the simulation. On the other hand, the TC in 10 m s-1 of VWS weakened significantly.Given the same VWS, the TC intensity is also found to be sensitive to TC size. Experiments with TCs with a smaller radius of 15 m s-1 wind reveal that while the TC in 2 m s-1 of VWS remains as intense as the CTRL, the TC in the 4 m s-1 VWS case weakened significantly to a minimal hurricane by the end of the simulation. A VWS of 6 m s-1 is strong enough to cause dissipation of the TC in 72 h. These results indicate that the size of a TC has to be taken into account in determining the intensity change of a TC in VWS.In the 10 m s-1 VWS case, the average temperature over the lower half of the troposphere within 50 km from the TC surface center is higher than that of the CTRL throughout the simulation. Such a warming, though of a small magnitude, is also observed for a brief period in the upper half of the troposphere before the rapid weakening of the TC and is related to the asymmetry of temperature required for a tilt of the vortex axis. The evolution of the vortex tilt is found to be similar to the dry simulations in previous studies, with the midlevel center (? = 0.525) located mainly in the southeast quadrant of the surface center. A tendency for the midlevel center to rotate about the surface center is also observed. These results support the idea that the resistance to <span class="hlt">vertical</span> tilt by the mutual rotation between the low-level and midlevel centers is also valid in the moist simulations.It is hypothesized that the secondary circulation and the associated diabatic heating reduce the <span class="hlt">vertical</span> tilt and the weakening. Condensation heating offsets the anomalous cooling effect due to the anomalous rising motion ahead of the vortex tilt. For small VWS, the <span class="hlt">vertical</span> motion asymmetry is not strong enough to destroy the complete secondary circulation and the eyewall. As a result, a large temperature asymmetry and the associated vortex tilt cannot develop. Furthermore, there is no entrainment of cool/dry air in the upper troposphere. Therefore, TCs under small shears can be as intense as the CTRL.Large-scale asymmetries in the form of anticyclones found in previous studies are also observed. These asymmetries are apparently related to the change of shears near the TCs. While the shears at outer radii stay roughly constant with time, the shears near the TC centers can have large temporal fluctuations both in magnitude and orientation. This result suggests that the location at which the VWS is estimated in observational studies could be important in determining the relationship between VWS and TC intensity change.<HR ALIGN="center" WIDTH="30%"></p> <div class="credits"> <p class="dwt_author">Wong, Martin L. M.; Chan, Johnny C. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">443</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5055968"> <span id="translatedtitle">Analytical model for a <span class="hlt">vertical</span> buoyant jet</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">An analytical model for a round and two-dimensional turbulent buoyant jet which is discharged <span class="hlt">vertically</span> into a stagnant ambient is developed. The buoyant jet is considered to have three separate zone models which are matched to form a complete solution. The velocity field is determined for the entire jet and plume regions by the use of an eddy viscosity which varies along the axis of the jet. The centerline decay of buoyancy is determined throughout and the results are compared to existing numerical codes. The model is applied to the disposal of carbon dioxide enriched seawater. The results can be used to provide design information for minimizing or maximizing the dilution of a discharge by the receiving environment.</p> <div class="credits"> <p class="dwt_author">Lee, D.W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">444</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007ApPhB..88..493M"> <span id="translatedtitle"><span class="hlt">Vertical</span> integration of ultrafast semiconductor lasers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Lasers generating short pulses - referred to as ultrafast lasers - enable many applications in science and technology. Numerous laboratory experiments have confirmed that ultrafast lasers can significantly increase telecommunication data rates [1], improve computer interconnects, and optically clock microprocessors [2, 3]. New applications in metrology [4], supercontinuum generation [5], and life sciences with two-photon microscopy [6] only work with ultrashort pulses but have relied on bulky and complex ultrafast solid-state lasers. Semiconductor lasers are ideally suited for mass production and widespread applications, because they are based on a wafer-scale technology with a high level of integration. Not surprisingly, the first lasers entering virtually every household were semiconductor lasers in compact disk players. Here we introduce a new concept and make the first feasibility demonstration of a new class of ultrafast semiconductor lasers which are power scalable, support both optical and electrical pumping and allow for wafer-scale fabrication. The laser beam propagates <span class="hlt">vertically</span> (perpendicularly) through the epitaxial layer structure which has both gain and absorber layers integrated. In contrast to edge-emitters, these lasers have semiconductor layers that can be optimized separately by using different growth parameters and with no regrowth. This is especially important to integrate the gain and absorber layers, which require different quantum confinement. A saturable absorber is required for pulse generation and we optimized its parameters with a single self-assembled InAs quantum dot layer at low growth temperatures. We refer to this class of devices as modelocked integrated external-cavity surface emitting lasers (MIXSEL). <span class="hlt">Vertical</span> integration supports a diffraction-limited circular output beam, transform-limited pulses, lower timing jitter, and synchronization to an external electronic clock. The pulse repetition rate scales from 1-GHz to 100-GHz by simply changing the laser cavity length. This result holds promise for semiconductor-based high-volume wafer-scale fabrication of compact, ultrafast lasers.</p> <div class="credits"> <p class="dwt_author">Maas, D. J. H. C.; Bellancourt, A.-R.; Rudin, B.; Golling, M.; Unold, H. J.; Südmeyer, T.; Keller, U.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">445</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/6758654"> <span id="translatedtitle">Modular low-aspect-<span class="hlt">ratio</span> high-beta torsatron</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">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-<span class="hlt">ratio</span> 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 <span class="hlt">vertical</span> 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.</p> <div class="credits"> <p class="dwt_author">Sheffield, G.V.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">446</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/864872"> <span id="translatedtitle">Modular low aspect <span class="hlt">ratio</span>-high beta torsatron</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">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 <span class="hlt">ratio</span> 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 <span class="hlt">vertical</span> 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.</p> <div class="credits"> <p class="dwt_author">Sheffield, George V. (Hopewell, NJ); Furth, Harold P. (Princeton, NJ)</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-02-07</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">447</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1828911"> <span id="translatedtitle">Evaluation of procalcitonin for diagnosis of neonatal sepsis of <span class="hlt">vertical</span> transmission</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Background The results of recent studies suggest the usefulness of PCT for early diagnosis of neonatal sepsis, with varying results. The aim of this prospective multicenter study was to determine the behavior of serum PCT concentrations in both uninfected and infected neonates, and to assess the value of this marker for diagnosis of neonatal sepsis of <span class="hlt">vertical</span> transmission. Methods PCT was measured in 827 blood samples collected prospectively from 317 neonates admitted to 13 acute-care teaching hospitals in Spain over one year. Serum PCT concentrations were determined by a specific immunoluminometric assay. The diagnostic efficacy of PCT at birth and within 12–24 h and 36–48 h of life was evaluated calculating the sensitivity, specificity, and likelihood <span class="hlt">ratio</span> of positive and negative results. Results 169 asymptomatic newborns and 148 symptomatic newborns (confirmed <span class="hlt">vertical</span> sepsis: 31, <span class="hlt">vertical</span> clinical sepsis: 38, non-infectious diseases: 79) were studied. In asymptomatic neonates, PCT values at 12–24 h were significantly higher than at birth and at 36–48 h of life. Resuscitation at birth and chorioamnionitis were independently associated to PCT values. Neonates with confirmed <span class="hlt">vertical</span> sepsis showed significantly higher PCT values than those with clinical sepsis. PCT thresholds for the diagnosis of sepsis were 0.55 ng/mL at birth (sensitivity 75.4%, specificity 72.3%); 4.7 ng/mL within 12–24 h of life (sensitivity 73.8%, specificity 80.8%); and 1.7 ng/mL within 36–48 h of life (sensitivity 77.6%, specificity 79.2%). Conclusion Serum PCT was moderately useful for the detection of sepsis of <span class="hlt">vertical</span> transmission, and its reliability as a maker of bacterial infection requires specific cutoff values for each evaluation point over the first 48 h of life.</p> <div class="credits"> <p class="dwt_author">Lopez Sastre, Jose B; Solis, David Perez; Serradilla, Vicente Roques; Colomer, Belen Fernandez; Cotallo, Gil D Coto</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">448</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20120009858&hterms=cloud&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dcloud"> <span id="translatedtitle">CALIPSO Observations of Transatlantic Dust: <span class="hlt">Vertical</span> Stratification and Effect of Clouds</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">CALIOP nighttime measurements of lidar backscatter, color and depolarization <span class="hlt">ratios</span> 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 <span class="hlt">ratios</span> both increase with altitude in the SAL; (2) lidar backscatter and color <span class="hlt">ratio</span> increase as dust is transported westward in the SAL; (3) the <span class="hlt">vertical</span> lapse rate of dust depolarization <span class="hlt">ratio</span> increases within SAL as plumes move westward; (4) nearby clouds barely affect the backscatter and color <span class="hlt">ratio</span> 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 <span class="hlt">ratio</span> 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.</p> <div class="credits"> <p class="dwt_author">Yang, Weidong; Marshak, Alexander; Varnai, Tamas; Kalashnikova, Olga V.; Kostinski, Alexander B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">449</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013OptRv..20..277T"> <span id="translatedtitle">Infants' sensitivity to <span class="hlt">vertical</span> disparity for depth perception</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Both horizontal and <span class="hlt">vertical</span> binocular disparities produce depth perception in adults. In developmental studies, infants aged around 4 to 6 months were shown to perceive depth from horizontal disparity. However, infants' sensitivity to <span class="hlt">vertical</span> disparity has not been shown clearly. To examine the sensitivity in infants, this study measured preferential looking behavior of infants aged 20 to 27 weeks. Results showed a significant preference for the stimulus with <span class="hlt">vertical</span> disparity, providing the first evidence of infants' sensitivity to <span class="hlt">vertical</span> disparity. The infants in the same age group did not show preference for stimulus with horizontal disparity when the stimulus were comparable to the stimulus with <span class="hlt">vertical</span> disparity, while their sensitivity to horizontal disparity was confirmed with the stimuli used in a previous study. Our results would suggest that properties in processing horizontal and <span class="hlt">vertical</span> disparities are different in infancy, and that the sensitivity to horizontal disparity are still premature in 27 weeks after birth.</p> <div class="credits"> <p class="dwt_author">Tsuruhara, Aki; Kaneko, Hirohiko; Kanazawa, So; Otsuka, Yumiko; Shirai, Nobu; Yamaguchi, Masami K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">450</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014HMT....50..721O"> <span id="translatedtitle">Numerical investigation of thermosolutal natural convection in a rectangular enclosure of an aspect <span class="hlt">ratio</span> four with heat and solute sources</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A numerical study of double-diffusive natural convection in an enclosure with a partial <span class="hlt">vertical</span> heat and mass sources for an aspect <span class="hlt">ratio</span> Ar = 4 has been carried out. The influence of various dimensionless parameters (Rayleigh number, buoyancy <span class="hlt">ratio</span>, 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.</p> <div class="credits"> <p class="dwt_author">Oueslati, Fakher; Ben-Beya, Brahim; Lili, Taieb</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">451</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/28234343"> <span id="translatedtitle"><span class="hlt">Vertical</span> Banded Gastroplasty--Gastric Bypass: preliminary report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Vertical</span> banded gastroplasty-gastric bypass is a surgical technique combining the advantages of the <span class="hlt">vertical</span> banded gastroplasty\\u000a with those of gastric bypass. The procedure was performed on 148 morbidly obese individuals: 83% were female and 17% were\\u000a male. Ages ranged from 15 to 64 years, with a mean age of 35. Mean percentage weight was 215% of ideal. The <span class="hlt">vertical</span> banded</p> <div class="credits"> <p class="dwt_author">Rafael F. Capella; Joseph F. Capella; Hernani Mandac; Prem Nath</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">452</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50994411"> <span id="translatedtitle"><span class="hlt">Vertical</span> junction high-efficiency concentrator photovoltaic cells</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the much lower conversion efficiency of the latter. We re-examine the efficiency achievable with Si <span class="hlt">Vertical</span> Multi-Junction (VMJ) cells consisting of series-connected <span class="hlt">vertical</span> p-n junctions within a single cell. A comprehensive 2D numerical analysis of a Si <span class="hlt">vertical</span> junction has been performed, over a wide range</p> <div class="credits"> <p class="dwt_author">Rona Sarfaty; Gideon Segev; Roni Pozner; Abraham Kribus; Yossi Rosenwaks</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">453</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54327493"> <span id="translatedtitle"><span class="hlt">Vertical</span> Junction Si Photovoltaic Cells for Concentrating PV</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the much lower conversion efficiency of the latter. We re-examine the efficiency achievable with Si <span class="hlt">Vertical</span> Multi-Junction (VMJ) cells consisting of series-connected <span class="hlt">vertical</span> p-n junctions within a single cell. A comprehensive 2D numerical analysis of a Si <span class="hlt">vertical</span> junction has been performed, over a wide range</p> <div class="credits"> <p class="dwt_author">Roni Pozner; Gideon Segev; Rona Sarfaty; Abraham Kribus; Yossi Rosenwaks</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">454</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/r61750322g236182.pdf"> <span id="translatedtitle"><span class="hlt">Vertical</span> visual-vestibular interaction in normal human subjects</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Summary  Previous studies have described asymmetrical <span class="hlt">vertical</span> eye movements when normal human subjects were rotated about a <span class="hlt">vertical</span>\\u000a inter-aural axis (with head rolled 90 degrees). We measured <span class="hlt">vertical</span> eye movements induced by visual, vestibular and visual-vestibular\\u000a stimuli with a magnetic scieral search coil technique while 10 normal subjects sat upright in a chair designed to rotate about\\u000a the horizontal inter-aural axis</p> <div class="credits"> <p class="dwt_author">R. W. Baloh; V. Honrubia; R. D. Yee; K. Jacobson</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">455</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2712701"> <span id="translatedtitle"><span class="hlt">Vertical</span> lid split approach for optic nerve sheath decompression</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">We describe a <span class="hlt">vertical</span> lid split orbitotomy approach to perform optic nerve sheath fenestration which was done in a patient with idiopathic intracranial hypertension. A <span class="hlt">vertical</span> lid split incision was used to enter the superomedial orbit and approach the optic nerve sheath. This approach resulted in a successful nerve sheath fenestration, with improvement in the patient's symptoms. The <span class="hlt">vertical</span> lid split incision provides access to the optic nerve sheath with minimal morbidity and may be an option for optic nerve sheath decompression.</p> <div class="credits"> <p class="dwt_author">Prabhakaran, Venkatesh C; Selva, Dinesh</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">456</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41981993"> <span id="translatedtitle">Average <span class="hlt">vertical</span> and zonal F region plasma drifts over Jicamarca</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The seasonal averages of the equatorial F region <span class="hlt">vertical</span> and zonal plasma drifts are determined using extensive incoherent scatter radar observations from Jicamarca during 1968-1988. The late afternoon and nighttime <span class="hlt">vertical</span> and zonal drifts are strongly dependent on the 10.7-cm solar flux. The authors show that the evening prereversal enhancement of <span class="hlt">vertical</span> drifts increases linearly with solar flux during equinox</p> <div class="credits"> <p class="dwt_author">B.G. Fejer; R.F. Woodman</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">457</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013ACPD...1318535P"> <span id="translatedtitle"><span class="hlt">Vertically</span> resolved aerosol properties by multi wavelengths lidar measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">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 <span class="hlt">vertical</span> 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 <span class="hlt">ratios</span> 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 <span class="hlt">vertical</span> 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.</p> <div class="credits"> <p class="dwt