Design and Analysis of Windmill Simulation and Pole by Solidwork Program

NASA Astrophysics Data System (ADS)

Mulyana, Tatang; Sebayang, Darwin; R, Akmal Muamar. D.; A, Jauharah H. D.; Yahya Shomit, M.

2018-03-01

The Indonesian state of archipelago has great wind energy potential. For micro-scale power generation, the energy obtained from the windmill can be connected directly to the electrical load and can be used without problems. However, for macro-scale power generation, problems will arise such as the design of vane shapes, there should be a simulation and an accurate experiment to produce blades with a special shape that can capture wind energy. In addition, daily and yearly wind and wind rate calculations are also required to ensure the best latitude and longitude positions for building windmills. This paper presents a solution to solve the problem of how to produce a windmill which in the builder is very practical and very mobile can be moved its location. Before a windmill prototype is built it should have obtained the best windmill design result. Therefore, the simulation of the designed windmill is of crucial importance. Solid simulation express is a tool that serves to generate simulation of a design. Some factors that can affect a design result include the power part and the rest part of the part, material selection, the load is given, the security of the design power made, and changes in shape due to treat the load given to the design made. In this paper, static and thermal simulations of windmills have been designed. Based on the simulation result on the designed windmill, it shows that the design has been made very satisfactory so that it can be done prototyping fabrication process.

Windmill Noise Annoyance, Visual Aesthetics, and Attitudes towards Renewable Energy Sources.

PubMed

Klæboe, Ronny; Sundfør, Hanne Beate

2016-07-23

A small focused socio-acoustic after-study of annoyance from a windmill park was undertaken after local health officials demanded a health impact study to look into neighborhood complaints. The windmill park consists of 31 turbines and is located in the South of Norway where it affects 179 dwellings. Simple exposure-effect relationships indicate stronger reactions to windmills and wind turbine noise than shown internationally, with the caveat that the sample size is small (n = 90) and responses are colored by the existing local conflict. Pulsating swishing sounds and turbine engine hum are the main causes of noise annoyance. About 60 per cent of those who participated in the survey were of the opinion that windmills degrade the landscape aesthetically, and were far from convinced that land-based windmills are desirable as a renewable energy source (hydropower is an important alternative source of renewables in Norway). Attitudes play an important role in addition to visual aesthetics in determining the acceptance of windmills and the resulting noise annoyance. To compare results from different wind turbine noise studies it seems necessary to assess the impact of important modifying factors.

14. Photocopy of Illustration from Buffet, Edward P., 'Some Long ...

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

14. Photocopy of Illustration from Buffet, Edward P., 'Some Long Island Windmills,' American Machinist, 17 October 1918, p. 728 STONE CRANE AT THE SHELTER ISLAND WINDMILL - Shelter Island Windmill, Manwaring Road, Shelter Island, Suffolk County, NY

9. NORTHEAST FROM SOUTH ENTRANCE ACROSS RECEIVING AREA OF FACTORY ...

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

9. NORTHEAST FROM SOUTH ENTRANCE ACROSS RECEIVING AREA OF FACTORY PAST THE GLASS-ENCLOSED OFFICE TOWARD SHOP AREA. BESIDE THE VERTICAL POST ROOF SUPPORT IN THE LEFT FOREGROUND IS A SCALE AND DRAFTING TABLE. BESIDE THE OFFICE WALL ON THE RIGHT IS A SMALL SHOP REPAIR BENCH, WHILE ABOVE THE OFFICE WINDOWS ARE BOXES OF COMPANY MANUSCRIPT BUSINESS RECORDS. THE WELDED METAL PIPE RACK IS A MODERN INTRUSION. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

Windmill Noise Annoyance, Visual Aesthetics, and Attitudes towards Renewable Energy Sources

PubMed Central

Klæboe, Ronny; Sundfør, Hanne Beate

2016-01-01

A small focused socio-acoustic after-study of annoyance from a windmill park was undertaken after local health officials demanded a health impact study to look into neighborhood complaints. The windmill park consists of 31 turbines and is located in the South of Norway where it affects 179 dwellings. Simple exposure-effect relationships indicate stronger reactions to windmills and wind turbine noise than shown internationally, with the caveat that the sample size is small (n = 90) and responses are colored by the existing local conflict. Pulsating swishing sounds and turbine engine hum are the main causes of noise annoyance. About 60 per cent of those who participated in the survey were of the opinion that windmills degrade the landscape aesthetically, and were far from convinced that land-based windmills are desirable as a renewable energy source (hydropower is an important alternative source of renewables in Norway). Attitudes play an important role in addition to visual aesthetics in determining the acceptance of windmills and the resulting noise annoyance. To compare results from different wind turbine noise studies it seems necessary to assess the impact of important modifying factors. PMID:27455301

Active control system for high speed windmills

DOEpatents

Avery, D.E.

1988-01-12

A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

Active control system for high speed windmills

DOEpatents

Avery, Don E.

1988-01-01

A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed.

Application of Terrestrial Laser Scanning to Study the Geometry of Slender Objects

NASA Astrophysics Data System (ADS)

Muszynski, Zbigniew; Milczarek, Wojciech

2017-12-01

Slender objects are a special group among the many types of industrial structures. These objects are characterized by a considerable height which is at least several times bigger than the diameter of the base. Mainly various types of industrial chimneys, as well as truss masts, towers, radio and television towers and also windmill columns belong to this group. During their operation slender objects are exposed to a number of unfavourable factors. For this reason, these objects require regular inspection, including geodetic measurements. In the paper the results of geodetic control of geometry of industrial chimney with a height of 120 m has been presented. The measurements were made by means of terrestrial laser scanning technique under rather unfavourable conditions (at night, during snowfall, with low air temperature) which allowed to verify the real usefulness and accuracy of this technique in engineering practice. On the basis of point cloud, the values of deviations from the vertical for main axis of the chimney have been calculated. Using point cloud, the selected horizontal cross sections of chimney were analysed and were compared with the archival geodetic documentation. On this basis the final conclusions about the advantages and limitations of the using of terrestrial laser scanning technique for the control of geometry of high industrial chimneys have been formulated.

Wind Energy Guide.

ERIC Educational Resources Information Center

Harrison, David

The booklet, intended for students and other visitors to the Lathrop E. Smith Environmental Education Center (Rockville, Maryland), explains how windmills work and their economic and environmental advantages. The history of windmills in Europe and Asia is briefly described, as well as the history of windmills and wind generators (for electricity)…

Generalization of turbojet and turbine-propeller engine performance in windmilling condition

NASA Technical Reports Server (NTRS)

Wallner, Ewis E; Welna, Henry J

1951-01-01

Windmilling characteristics of several turbojet and turbine-propeller engines were investigated individually over a wide range of flight conditions in the NACA Lewis altitude wind tunnel. A study was made of all these data and windmilling performance of gas turbine engines was generalized. Although internal-drag, air-flow, and total-pressure-drop parameters were generalized to a single curve for both the axial-flow type engines and another for the centrifugal-flow engine. The engine speed, component pressure changes, and windmilling-propeller drag were generalized to single curves for the two turbine-propeller-type engines investigated. By the use of these curves the windmilling performance can be estimated for axial-flow type gas turbine engines similar to the types investigated over a wide range of flight conditions.

37. NORTH TO BINS ALONG NORTH WALL OF FACTORY BUILDING ...

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

37. NORTH TO BINS ALONG NORTH WALL OF FACTORY BUILDING WHICH REMAIN FILLED WITH NEW OLD STOCK AND USED PARTS FOR ELI WINDMILLS. THE ROPE AT THE LOWER FOREGROUND WAS USED IN ERECTING WINDMILLS AND TOWERS FOR CUSTOMERS. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

31. WEST TO PARTS AND TOOLS LOCATED DIRECTLY OPPOSITE FROM ...

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

31. WEST TO PARTS AND TOOLS LOCATED DIRECTLY OPPOSITE FROM THE BLACKSMITH SHOP AREA IN THE NORTHEAST QUADRANT OF THE FACTORY. ON THE FLOOR AT THE LEFT SIDE IS A MANUAL PIPE THREADER FOR LARGE-DIAMETER PIPE (AS DROP PIPE IN WELLS FOR WATER SYSTEMS). BENEATH THE BENCH ARE UNMACHINED NEW OLD STOCK MAIN CASTINGS FOR ELI WINDMILLS, TOGETHER WITH A USED MAIN SHAFT/WHEEL HUB/CRANK PLATE ASSEMBLY WITH 1920S-1930S OIL RESERVOIR FROM ELI WINDMILL. THE CIRCULAR CASTING WITH CRESCENT-SHAPED PATTERNS IS A PORTION OF THE CAM MECHANISM FROM A 'WESTERN GEARED GEARLESS' WINDMILL MADE BY THE WESTERN LAND ROLLER CO., HASTINGS, NEB. TO THE RIGHT ON THE BENCH IS A GEARED TIRE BENDER USED TO GIVE CURVATURE TO WHEEL RIMS OF ELI WINDMILLS. IN THE BACKGROUND ARE ... - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

A comment on towers for windmills. [structural and economic criteria

NASA Technical Reports Server (NTRS)

Budgen, H. P.

1973-01-01

Design considerations for windmill tower structures include the effects of normal wind forces on the rotor and on the tower. Circular tabular or masonry towers present a relatively simple aerodynamic solution. Economic factors establish the tubular tower as superior for small and medium sized windmills. Concrete and standard concrete block designs are cheaper than refabricated steel structures that have to be freighted.

23. NORTHEAST TO CIRCA 1875 POWER SHEAR, PUNCH, AND RIVETING ...

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

23. NORTHEAST TO CIRCA 1875 POWER SHEAR, PUNCH, AND RIVETING MACHINE SET UP TO DEMONSTRATE USE IN RIVETING COMPONENTS OF WHEEL ARMS FOR ELI WINDMILLS. HISTORIC DEBRIS FROM PUNCHING WORK IS VISIBLE BENEATH THE MACHINE IN THE OPERATOR'S PIT.' ON THE LEFT IS A U-SHAPED LOVEJOY FIELD PUNCH FOR USE IN INSTALLING STEEL WINDMILL/TOWER COMPONENTS. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

Steerable vertical to horizontal energy transducer for mobile robots

DOEpatents

Spletzer, Barry L.; Fischer, Gary J.; Feddema, John T.

2001-01-01

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

Orientation of human optokinetic nystagmus to gravity: a model-based approach

NASA Technical Reports Server (NTRS)

Gizzi, M.; Raphan, T.; Rudolph, S.; Cohen, B.

1994-01-01

Optokinetic nystagmus (OKN) was induced by having subjects watch a moving display in a binocular, head-fixed apparatus. The display was composed of 3.3 degrees stripes moving at 35 degrees/s for 45 s. It subtended 88 degrees horizontally by 72 degrees vertically of the central visual field and could be oriented to rotate about axes that were upright or tilted 45 degrees or 90 degrees. The head was held upright or was tilted 45 degrees left or right on the body during stimulation. Head-horizontal (yaw axis) and head-vertical (pitch axis) components of OKN were recorded with electro-oculography (EOG). Slow phase velocity vectors were determined and compared with the axis of stimulation and the spatial vertical (gravity axis). With the head upright, the axis of eye rotation during yaw axis OKN was coincident with the stimulus axis and the spatial vertical. With the head tilted, a significant vertical component of eye velocity appeared during yaw axis stimulation. As a result the axis of eye rotation shifted from the stimulus axis toward the spatial vertical. Vertical components developed within 1-2 s of stimulus onset and persisted until the end of stimulation. In the six subjects there was a mean shift of the axis of eye rotation during yaw axis stimulation of approximately 18 degrees with the head tilted 45 degrees on the body. Oblique optokinetic stimulation with the head upright was associated with a mean shift of the axis of eye rotation toward the spatial vertical of 9.2 degrees. When the head was tilted and the same oblique stimulation was given, the axis of eye rotation rotated to the other side of the spatial vertical by 5.4 degrees. This counterrotation of the axis of eye rotation is similar to the "Muller (E) effect," in which the perception of the upright is counterrotated to the opposite side of the spatial vertical when subjects are tilted in darkness. The data were simulated by a model of OKN with a "direct" and "indirect" pathway. It was assumed that the direct visual pathway is oriented in a body, not a spatial frame of reference. Despite the short optokinetic after-nystagmus time constants, strong horizontal to vertical cross-coupling could be produced if the horizontal and vertical time constants were in proper ratio and there were no suppression of nystagmus in directions orthogonal to the stimulus direction. The model demonstrates that the spatial orientation of OKN can be achieved by restructuring the system matrix of velocity storage. We conclude that an important function of velocity storage is to orient slow-phase velocity toward the spatial vertical during movement in a terrestrial environment.

Windmill-task as a New Quantitative and Objective Assessment for Mirror Movements in Unilateral Cerebral Palsy: A Pilot Study.

PubMed

Zielinski, Ingar Marie; Steenbergen, Bert; Schmidt, Anna; Klingels, Katrijn; Simon Martinez, Cristina; de Water, Pascal; Hoare, Brian

2018-03-23

To introduce the Windmill-task, a new objective assessment tool to quantify the presence of mirror movements (MMs) in children with unilateral cerebral palsy (UCP), which are typically assessed with the observation-based Woods and Teuber scale (W&T). Prospective, observational, cohort pilot study. Children's hospital. Prospective cohort of children (N=23) with UCP (age range, 6-15y, mean age, 10.5±2.7y). Not applicable. The concurrent validity of the Windmill-task is assessed, and the sensitivity and specificity for MM detection are compared between both assessments. To assess the concurrent validity, Windmill-task data are compared with W&T data using Spearman rank correlations (ρ) for 2 conditions: affected hand moving vs less affected hand moving. Sensitivity and specificity are compared by measuring the mean percentage of children being assessed inconsistently across both assessments. Outcomes of both assessments correlated significantly (affected hand moving: ρ=.520; P=.005; less affected hand moving: ρ=.488; P=.009). However, many children displayed MMs on the Windmill-task, but not on the W&T (sensitivity: affected hand moving: 27.5%; less affected hand moving: 40.6%). Only 2 children displayed MMs on the W&T, but not on the Windmill-task (specificity: affected hand moving: 2.9%; less affected hand moving: 1.4%). The Windmill-task seems to be a valid tool to assess MMs in children with UCP and has an additional advantage of sensitivity to detect MMs. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Pump control system for windmills

DOEpatents

Avery, Don E.

1983-01-01

A windmill control system having lever means, for varying length of stroke of the pump piston, and a control means, responsive to the velocity of the wind to operate the lever means to vary the length of stroke and hence the effective displacement of the pump in accordance with available wind energy, with the control means having a sensing member separate from the windmill disposed in the wind and displaceable thereby in accordance with wind velocity.

Dynamics of tethered constellations in Earth orbit

NASA Technical Reports Server (NTRS)

Lorenzini, E.

1986-01-01

Topics covered include station keeping of single-axis and two-axis constellations; single-axis vertical constellations with low-g platform; single-axis vertical constellations with three masses; deployment strategy; and damping of vibrational modes.

Windmills: Ancestors of the wind power generation

NASA Astrophysics Data System (ADS)

Rossi, Cesare; Russo, Flavio; Savino, Sergio

2017-09-01

A brief description of the windmills from the second millennium BC to the Renaissance is presented. This survey is a part of several studies conducted by the authors on technology in the ancient world. The windmills are the first motor, other than human muscles, and are the ancestors of the modern wind turbines. Some authors' virtual reconstructions of old windmills are also presented. The paper shows that the operating principle of many modern machines had already been conceived in the ancient times by using a technology that was more advanced than expected, but with two main differences, as follows: Similar tasks were accomplished by using much less energy; and the environmental impact was nil or very low. Modern designers should sometimes consider simplicity rather than the use of a large amount of energy.

Vertical axis wind turbine airfoil

DOEpatents

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

2012-12-18

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

A local-circulation model for Darrieus vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Masse, B.

1986-04-01

A new computational model for the aerodynamics of the vertical-axis wind turbine is presented. Based on the local-circulation method generalized for curved blades, combined with a wake model for the vertical-axis wind turbine, it differs markedly from current models based on variations in the streamtube momentum and vortex models using the lifting-line theory. A computer code has been developed to calculate the loads and performance of the Darrieus vertical-axis wind turbine. The results show good agreement with experimental data and compare well with other methods.

The development and testing of a novel cross axis wind turbine

NASA Astrophysics Data System (ADS)

Chong, W. T.; Muzammil, W. K.; Gwani, M.; Wong, K. H.; Fazlizan, A.; Wang, C. T.; Poh, S. C.

2016-06-01

A novel cross axis wind turbine (CAWT) which comprises of a cross axis blades arrangement was presented and investigated experimentally. The CAWT is a new type of wind turbine that extracts wind energy from airflow coming from the horizontal and vertical directions. The wind turbine consists of three vertical blades and six horizontal blades arranged in a cross axis orientation. Hubs in the middle of the CAWT link the horizontal and vertical blades through connectors to form the CAWT. The study used a 45° deflector to guide the oncoming airflow upward (vertical wind direction). The results from the study showed that the CAWT produced significant improvements in power output and rotational speed performance compared to a conventional straight-bladed vertical axis wind turbine (VAWT).

Determination of the number of Vertical Axis Wind Turbine blades based on power spectrum

NASA Astrophysics Data System (ADS)

Fedak, Waldemar; Anweiler, Stanisław; Gancarski, Wojciech; Ulbrich, Roman

2017-10-01

Technology of wind exploitation has been applied widely all over the world and has already reached the level in which manufacturers want to maximize the yield with the minimum investment outlays. The main objective of this paper is the determination of the optimal number of blades in the Cup-Bladed Vertical Axis Wind Turbine. Optimizing the size of the Vertical Axis Wind Turbine allows the reduction of costs. The maximum power of the rotor is selected as the performance target. The optimum number of Vertical Axis Wind Turbine blades evaluation is based on analysis of a single blade simulation and its superposition for the whole rotor. The simulation of working blade was done in MatLab environment. Power spectrum graphs were prepared and compared throughout superposition of individual blades in the Vertical Axis Wind Turbine rotor. The major result of this research is the Vertical Axis Wind Turbine power characteristic. On the basis of the analysis of the power spectra, optimum number of the blades was specified for the analysed rotor. Power spectrum analysis of wind turbine enabled the specification of the optimal number of blades, and can be used regarding investment outlays and power output of the Vertical Axis Wind Turbine.

Genetics Home Reference: Freeman-Sheldon syndrome

MedlinePlus

... the fifth finger ( ulnar deviation , also called "windmill vane hand"), and inward- and downward-turning feet ( clubfoot ). ... 2A FSS whistling face syndrome whistling face-windmill vane hand syndrome Related Information How are genetic conditions ...

10 CFR 1002.11 - Description of official seal.

Code of Federal Regulations, 2013 CFR

2013-01-01

... is emblazoned a gold-colored symbolic sun, atom, oil derrick, windmill, and dynamo. It is crested by... increasing demands for energy. The sun, atom, oil derrick, windmill, and dynamo serve as representative...

10 CFR 1002.11 - Description of official seal.

Code of Federal Regulations, 2010 CFR

2010-01-01

... is emblazoned a gold-colored symbolic sun, atom, oil derrick, windmill, and dynamo. It is crested by... increasing demands for energy. The sun, atom, oil derrick, windmill, and dynamo serve as representative...

10 CFR 1002.11 - Description of official seal.

Code of Federal Regulations, 2011 CFR

2011-01-01

... is emblazoned a gold-colored symbolic sun, atom, oil derrick, windmill, and dynamo. It is crested by... increasing demands for energy. The sun, atom, oil derrick, windmill, and dynamo serve as representative...

10 CFR 1002.11 - Description of official seal.

Code of Federal Regulations, 2014 CFR

2014-01-01

... is emblazoned a gold-colored symbolic sun, atom, oil derrick, windmill, and dynamo. It is crested by... increasing demands for energy. The sun, atom, oil derrick, windmill, and dynamo serve as representative...

10 CFR 1002.11 - Description of official seal.

Code of Federal Regulations, 2012 CFR

2012-01-01

... is emblazoned a gold-colored symbolic sun, atom, oil derrick, windmill, and dynamo. It is crested by... increasing demands for energy. The sun, atom, oil derrick, windmill, and dynamo serve as representative...

Aeroelastically coupled blades for vertical axis wind turbines

DOEpatents

Paquette, Joshua; Barone, Matthew F.

2016-02-23

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

Why the long face? The importance of vertical image structure for biological "barcodes" underlying face recognition.

PubMed

Spence, Morgan L; Storrs, Katherine R; Arnold, Derek H

2014-07-29

Humans are experts at face recognition. The mechanisms underlying this complex capacity are not fully understood. Recently, it has been proposed that face recognition is supported by a coarse-scale analysis of visual information contained in horizontal bands of contrast distributed along the vertical image axis-a biological facial "barcode" (Dakin & Watt, 2009). A critical prediction of the facial barcode hypothesis is that the distribution of image contrast along the vertical axis will be more important for face recognition than image distributions along the horizontal axis. Using a novel paradigm involving dynamic image distortions, a series of experiments are presented examining famous face recognition impairments from selectively disrupting image distributions along the vertical or horizontal image axes. Results show that disrupting the image distribution along the vertical image axis is more disruptive for recognition than matched distortions along the horizontal axis. Consistent with the facial barcode hypothesis, these results suggest that human face recognition relies disproportionately on appropriately scaled distributions of image contrast along the vertical image axis. © 2014 ARVO.

Quasi-Sun-Pointing of Spacecraft Using Radiation Pressure

NASA Technical Reports Server (NTRS)

Spilker, Thomas

2003-01-01

A report proposes a method of utilizing solar-radiation pressure to keep the axis of rotation of a small spin-stabilized spacecraft pointed approximately (typically, within an angle of 10 deg to 20 deg) toward the Sun. Axisymmetry is not required. Simple tilted planar vanes would be attached to the outer surface of the body, so that the resulting spacecraft would vaguely resemble a rotary fan, windmill, or propeller. The vanes would be painted black for absorption of Solar radiation. A theoretical analysis based on principles of geometric optics and mechanics has shown that torques produced by Solar-radiation pressure would cause the axis of rotation to precess toward Sun-pointing. The required vane size would be a function of the angular momentum of the spacecraft and the maximum acceptable angular deviation from Sun-pointing. The analysis also shows that the torques produced by the vanes would slowly despin the spacecraft -- an effect that could be counteracted by adding specularly reflecting "spin-up" vanes.

The Windmill technique avoids manual removal of the retained placenta-A new solution for an old problem.

PubMed

Hinkson, Larry; Suermann, Mia Amelie; Hinkson, Susan; Henrich, Wolfgang

2017-08-01

The primary objective is to assess the reduction in manual removal of placenta with the Windmill technique of placenta delivery in patients with retained placenta. The Windmill technique involves the application of continuous 360° umbilical cord traction and rotation in such a manner as to be perpendicular to the direction of the birth canal at the level of the introitus. This rotation through 360° is repeated slowly with movement akin to the motion of the blades of a windmill. We performed a 3-year retrospective case-control study at the Charité University Hospital in Berlin. Patients with a retained placenta more than 30min following failed traditional interventions were consented and offered the Windmill technique of placenta delivery. Study cases were compared to controls where an operative manual removal of placenta was performed. Patients with suspected placenta implantation problems, uterine atony, bleeding due to vaginal tract injury and coagulation disturbances were excluded. Over the study period 14 patients were recruited to the study arm and 17 patients were in the control group. With the Windmill technique for retained placenta, 86% (12/14, p<0.001) of patients avoided invasive operative manual removal of the placenta in theatre. There was a statistically significant reduction in mean blood loss (429ml vs 724ml, p=0.001) and mean postoperative fall in hemoglobin values (1.3g/dl vs 2.5g/dl, p=0.04). There was a reduction in the time to delivery of the placenta, antibiotic prophylaxis and use of general anesthesia. The Windmill technique for the delivery of the retained placenta is a simple, safe, effective and easy to teach technique that reduces invasive operative manual removal of the placenta, postpartum blood loss and delay in the placenta delivery. This innovative technique can also be a lifesaving intervention especially in areas with limited or no access to operative facilities. Copyright © 2017 Elsevier B.V. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

The Combination of Coastal Resources Potential: Development of Windmill Techno Park in the Context of Edutourism and Hinterland Analysis

NASA Astrophysics Data System (ADS)

Hasanuddin, H.; Nurdin, H.; Waskito, W.; Refdinal, R.

2018-04-01

There are many coastal cities in Indonesia, among them the city of Padang and Pariaman in West Sumatra with the ownership of the grace of coastal resources, such as stunning coastal scenery and wind energy that can be converted to its potential. These two types of resources need to be combined utilization especially in relation to the development of tourism so as to have an impact on the regional development and the cities growth. This paper discusses of information related to the potential of coastal resources used as a parameter development of windmill techno park in the context of educational tourism. The discussion focuses on locational aspects and consideration of the design and modification for the windmill model to the enhancement of tourist attraction. In addition, it is also studying the presence of the windmill techno park as a development center in the context of hinterland in the regional analysis. Through the measurement results obtained average wind speed (2.5 - 6.5) m/s and meet the standards & criteria as a windmill design variables. While the geomorphology of the region, its location has a breathtaking coastal landscape as a tourist destination. Then through gravity analysis, the location of the windmill techno park development provides optimum strength to the growth of the city of Padang, with the value of interaction strength is higher than other regions. This means as a sub-urban area of the city the existence of windshield techno park later can support economic development and growth of cities around the coast.

Repeatability and oblique flow response characteristics of current meters

USGS Publications Warehouse

Fulford, Janice M.; Thibodeaux, Kirk G.; Kaehrle, William R.; ,

1993-01-01

Laboratory investigation into the precision and accuracy of various mechanical-current meters are presented. Horizontal-axis and vertical-axis meters that are used for the measurement of point velocities in streams and rivers were tested. Meters were tested for repeatability and response to oblique flows. Both horizontal- and vertical-axis meters were found to under- and over-register oblique flows with errors generally increasing as the velocity and angle of flow increased. For the oblique flow tests, magnitude of errors were smallest for horizontal-axis meters. Repeatability of all meters tested was good, with the horizontal- and vertical-axis meters performing similarly.

Windmills in the light of modern research

NASA Technical Reports Server (NTRS)

Betz, A

1928-01-01

The chief contribution of modern research in the field of windmills is a better understanding of the phenomena and of the available means for the accomplishment of certain results, but also of the natural limits to their productive capacity.

16. SOUTH TO VIEW OF CIRCA 1900 MICHIGAN MACHINERY MFG. ...

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

16. SOUTH TO VIEW OF CIRCA 1900 MICHIGAN MACHINERY MFG. CO. PUNCH PRESS WITH WOOD-BURNING HEATING STOVE LOCATED IN THE CENTER OF THE FACTORY BUILDING. BESIDE THE HEATING STOVE, POINTING TOWARD THE PUNCH PRESS, IS A JIG USED TO POSITION ANGLE STEEL COMPONENTS OF STEEL WINDMILL TOWER LEGS FOR PUNCHING BOLT HOLES. THE SUPPORT FOR THE BRICK FLUE OF THE HEATING STOVE IS CONSTRUCTED FROM SALVAGED GALVANIZED ANGLE STEEL OF THE TYPE USED IN FABRICATING WINDMILL TOWERS MANUFACTURED IN THE FACTORY. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

A Windmill's Theoretical Maximum Extraction of Power from the Wind.

ERIC Educational Resources Information Center

Inglis, David Rittenhouse

1979-01-01

Explains that the efficiency and the useful power available from a windmill turbine, of a laminar-flow model, will vary due to rotational kinetic energy of the downwind stream and turbulent mixing from outside the boundaries of the idealized stream. (GA)

11. STOVE NUT USED IN THE MILL WHEN THE BRAKE ...

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

11. STOVE NUT USED IN THE MILL WHEN THE BRAKE WHEEL DROVE ONE PAIR OF MILLSTONES DIRECTLY; FOUND ON THE FIRST FLOOR OF THE WINDMILL AT WATERMILL - Windmill at Water Mill, Montauk Highway & Halsey Lane, Water Mill, Suffolk County, NY

Preliminary Paleomagnetically Determined Vertical-Axis Rotations and their Relationship to Extensional Events of the Southern Walker Lane

NASA Astrophysics Data System (ADS)

Johnson, S.; Geissman, J. W.; Katopody, D. T.; Kerstetter, S. R.; Oldow, J. S.

2016-12-01

The northern part of the southern Walker Lane experienced three extensional events from the late Oligocene to the Holocene: 1) late Oligocene to early Miocene WNW and ENE trending half-grabens, 2) Late Miocene to early Pliocene high-magnitude extension on a low-angle normal fault, and 3) contemporary transtensional deformation that initiated at 4 Ma. Each of the extensional events controlled deposition of synextensional strata. What is less understood is the timing and magnitude of vertical axis rotation and its relationship to each of the three extensional events. As part of a recent and ongoing multidisciplinary study to better understand the complex nature and history of these extensional events we present preliminary paleomagnetic data from 55 sites in Miocene extrusive igneous rocks which record that clockwise vertical-axis rotation played a significant role in accommodating displacement in these systems. Recently refined stratigraphic, geochronologic, and structural controls have allowed the detailed paleomagnetic sampling required for this study. We seek to provide better constraints on timing, areal extent, and distribution of vertical axis rotation to answer how vertical axis rotation interacted with these extensional events. Consistent with past studies, we have recognized 20-30 degrees of clockwise vertical-axis rotation distributed heterogeneously throughout the study area. However, clockwise vertical-axis rotations are no longer occurring in this region as evidenced by modern geodetic velocity fields. The accommodation of displacement by vertical axis rotations in this region likely ceased by early Pliocene to late Miocene when the structural step-over migrated to the northwest to its present day manifestation in the Mina Deflection. Anisotropy of magnetic susceptibility (AMS), used as a proxy for flow direction in igneous extrusive rocks, provides evidence that at least one late Oligocene-early Miocene half-grabens acted as near-source depositional centers concurrent with extension.

Investigation of a generator system for generating electrical power, to supply directly to the public network, using a windmill

NASA Technical Reports Server (NTRS)

Tromp, C.

1979-01-01

A windpowered generator system is described which uses a windmill to convert mechanical energy to electrical energy for a three phase (network) voltage of constant amplitude and frequency. The generator system controls the windmill by the number of revolutions so that the power drawn from the wind for a given wind velocity is maximum. A generator revolution which is proportional to wind velocity is achieved. The stator of the generator is linked directly to the network and a feed converter at the rotor takes care of constant voltage and frequency at the stator.

Wind power demonstration and siting problems. [for recharging electrically driven automobiles

NASA Technical Reports Server (NTRS)

Bergey, K. H.

1973-01-01

Technical and economic feasibility studies on a small windmill to provide overnight charging for an electrically driven car are reported. The auxiliary generator provides power for heating and cooling the vehicle which runs for 25 miles on battery power alone, and for 50 miles with the onboard charger operating. The blades for this windmill have a diameter of 12 feet and are coupled through to a conventional automobile alternator so that they are able to completely recharge car batteries in 8 hours. Optimization of a windmill/storage system requires detailed wind velocity information which permits rational sitting of wind power system stations.

a review and an update on the winter lightning that occurred on a rotating windmill and its standalone lightning protection tower

NASA Astrophysics Data System (ADS)

Wang, D.; Takagi, N.

2012-12-01

We have observed the lightning occurred on a 100 m high windmill and its 105 m high standalone lightning-protection tower about 45 m separated from the windmill in the Hokuriku area of Japan for 7 consecutive winter seasons from 2005 to 2012. Our main observation items include: (1) Lightning current at the bottom of both the windmill and the tower. (2) Thunderstorm electric fields and the electric field changes caused by lightning at multiple sites. (3) Optical images by both low and high speed imaging systems. During the 7 winter seasons, over 100 lightning have hit either the tower or the windmill or both. All the lightning but two observed are of upward lightning. Those upward lightning can be sub-classified into self-initiated types and other-triggered types according to whether there is a discharge activity prior to the upward leaders or not. Self-initiated and other-triggered upward lightning tend to have biased percentages in terms of striking locations (windmill versus tower) and thunderstorm types (active versus weak). All the upward lightning but one contained only initial continuous current stages. In the presentation, we will first give a review on those results we have reported before [1-3]. As an update, we will report the following results. (1) The electric field change required for triggering a negative upward leader is usually more than twice bigger than that for triggering a positive upward leader. (2) An electric current pulse with an amplitude of several tens of Amperes along a high structure has been observed to occur in response to a rapid electric change generated by either a nearby return stroke or K-change. References [1] D.Wang, N.Takagi, T.Watanebe, H. Sakurano, M. Hashimoto, Observed characteristics of upward leaders that are initiated from a windmill and its lightning protection tower, Geophys. Res. Lett., Vol.35, L02803, doi:10.1029/2007GL032136, 2008. [2] W. Lu, D.Wang, Y. Zhang and N. Takagi, Two associated upward lightning flashes that produced opposite polarity electric field changes, Geophys. Res. Lett., Vol.36, L05801, doi:10.1029/2008GL036598, 2009. [3] D. Wang, N. Takagi, Characteristics of Winter Lightning that Occurred on a Windmill and its Lightning Protection Tower in Japan, IEEJ Trans. on Power and Energy, Vol. 132, No.6, pp.568-572, Doi:10.1541/ieejpes.132.568, 2012.

Surface Electromyography of the Forearm Musculature During the Windmill Softball Pitch

PubMed Central

Remaley, D. Trey; Fincham, Bryce; McCullough, Bryan; Davis, Kirk; Nofsinger, Charles; Armstrong, Charles; Stausmire, Julie M.

2015-01-01

Background: Previous studies investigating the windmill softball pitch have focused primarily on shoulder musculature and function, collecting limited data on elbow and forearm musculature. Little information is available in the literature regarding the forearm. This study documents forearm muscle electromyographic (EMG) activity that has not been previously published. Purpose: Elbow and upper extremity overuse injuries are on the rise in fast-pitch softball pitchers. This study attempts to describe forearm muscle activity in softball pitchers during the windmill softball pitch. Overuse injuries can be prevented if a better understanding of mechanics is defined. Study Design: Descriptive laboratory study. Methods: Surface EMG and high-speed videography was used to study forearm muscle activation patterns during the windmill softball pitch on 10 female collegiate-level pitchers. Maximum voluntary isometric contraction of each muscle was used as a normalizing value. Each subject was tested during a single laboratory session per pitcher. Data included peak muscle activation, average muscle activation, and time to peak activation for 6 pitch types: fastball, changeup, riseball, curveball, screwball, and dropball. Results: During the first 4 phases, muscle activity (seen as signal strength on the EMG recordings) was limited and static in nature. The greatest activation occurred in phases 5 and 6, with increased signal strength, evidence of stretch-shortening cycle, and different muscle characteristics with each pitch style. These 2 phases of the windmill pitch are where the arm is placed in the 6 o’clock position and then at release of the ball. The flexor carpi ulnaris signal strength was significantly greater than the other forearm flexors. Timing of phases 1 through 5 was successively shorter for each pitch. There was a secondary pattern of activation in the flexor carpi ulnaris in phase 4 for all pitches except the fastball and riseball. Conclusion: During the 6 pitches, the greatest muscular activity was in phases 5 and 6. Flexor carpi ulnaris activity was greatest among the muscles tested. The riseball had the highest peak activity, but the curveball and dropball had the highest average signal strength. This muscle activity correlates with increasing distraction in the elbow, suggesting that flexor muscles act to counterdistract the elbow as they do for the baseball pitch. Clinical Relevance: Windmill pitchers are unique among overhead athletes as they throw, on average, more pitches per overhead athlete. Understanding the mechanics and physiology of the elbow in windmill pitchers is crucial to prevention and treatment of these increasingly common elbow injuries. This study establishes baseline data that will be useful to further prevent windmill pitch elbow injury. PMID:26535372

Variability of a "force signature" during windmill softball pitching and relationship between discrete force variables and pitch velocity.

PubMed

Nimphius, Sophia; McGuigan, Michael R; Suchomel, Timothy J; Newton, Robert U

2016-06-01

This study assessed reliability of discrete ground reaction force (GRF) variables over multiple pitching trials, investigated the relationships between discrete GRF variables and pitch velocity (PV) and assessed the variability of the "force signature" or continuous force-time curve during the pitching motion of windmill softball pitchers. Intraclass correlation coefficient (ICC) for all discrete variables was high (0.86-0.99) while the coefficient of variance (CV) was low (1.4-5.2%). Two discrete variables were significantly correlated to PV; second vertical peak force (r(5)=0.81, p=0.03) and time between peak forces (r(5)=-0.79; p=0.03). High ICCs and low CVs support the reliability of discrete GRF and PV variables over multiple trials and significant correlations indicate there is a relationship between the ability to produce force and the timing of this force production with PV. The mean of all pitchers' curve-average standard deviation of their continuous force-time curves demonstrated low variability (CV=4.4%) indicating a repeatable and identifiable "force signature" pattern during this motion. As such, the continuous force-time curve in addition to discrete GRF variables should be examined in future research as a potential method to monitor or explain changes in pitching performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of commercially available seat suspensions to reduce whole body vibration exposures in mining heavy equipment vehicle operators.

PubMed

Kim, Jeong Ho; Marin, Luz S; Dennerlein, Jack T

2018-09-01

As mining vehicle operators are exposed to high level of Whole body vibration (WBV) for prolonged periods of time, approaches to reduce this exposure are needed for the specific types of exposures in mining. Although various engineering controls (i.e. seat suspension systems) have been developed to address WBV, there has been lack of research to systematically evaluate these systems in reducing WBV exposures in mining heavy equipment vehicle settings. Therefore, this laboratory-based study evaluated the efficacy of different combinations of fore-aft (x-axis), lateral (y-axis), and vertical (z-axis) suspensions in reducing WBV exposures. The results showed that the active vertical suspension more effectively reduced the vertical vibration (∼50%; p's < 0.0001) as compared to the passive vertical suspension (10%; p's < 0.11). The passive fore-aft (x-axis) and lateral (y-axis) suspension systems did not attenuate the corresponding axis vibration (p's > 0.06) and sometimes amplified the floor vibration, especially when the non-vertical vibration was predominant (p's < 0.02). These results indicate that there is a critical need to develop more effective engineering controls including better seat suspensions to address non-vertical WBV exposures, especially because these non-vertical WBV exposures can increase risks for adverse health effects including musculoskeletal loading, discomfort, and impaired visual acuity. Copyright © 2018 Elsevier Ltd. All rights reserved.

61. DETAIL OF HEAD, VANE STEM, VANE HINGE, AND WHEEL ...

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

61. DETAIL OF HEAD, VANE STEM, VANE HINGE, AND WHEEL OF AN ELI WINDMILL ON THE GROUND AT THE STOLL RESIDENCE ABOUT 1-1/2 MILES WEST OF NEBRASKA CITY ON STEAM WAGON ROAD. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

State of the art in protection of erosion-corrosion on vertical axis tidal current turbine

NASA Astrophysics Data System (ADS)

Musabikha, Siti; Utama, I. Ketut Aria Pria; Mukhtasor

2018-05-01

Vertical axis tidal current turbine is main part of ocean energy devices which converts the tidal current energy into electricity. Its development is arising too due to increased interest research topic concerning climate change mitigation. Due to its rotating movement, it will be induced mechanical forces, such as shear stress and/or particle impact. Because of its natural operations, vertical axis turbine is also being exposed to harsh and corroding marine environment itself. In order to secure the vertical tidal turbine devices from mechanical wear and corrosion effects which is lead to a material loss, an appropriate erosion-corrosion protection needs to be defined. Its protection actionscan be derived such as design factors, material selections, inhibitors usage, cathodic protections, and coatings. This paper aims to analyze protection method which is necessary to control erosion-corrosion phenomenon that appears to the vertical axis tidal current turbine.

36. SOUTHWEST TO BELTPOWERED CIRCA 1900 DROP HAMMER IN NORTHEASTERN ...

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

36. SOUTHWEST TO BELT-POWERED CIRCA 1900 DROP HAMMER IN NORTHEASTERN QUADRANT OF FACTORY OPPOSITE FROM THE BLACKSMITH SHOP AREA. THIS MACHINE WAS USED TO SHAPE THE STEEL VANE HINGE PART AFTER IT WAS HEATED IN THE FORGE IN THE ADJACENT BLACKSMITH SHOP AREA. USE OF THE ROTATING POWER OF THE PULLEY AT THE TO MADE LIFTING THE HAMMER COMPARATIVELY QUICK AND EASY. AROUND THE MACHINE ARE WHEEL PARTS FOR ELI WINDMILLS. AT THE LEFT FOREGROUND IS A CIRCA 1900 FOUR-SPINDLE PRODUCTION DRILL PRESS WHICH WAS RELOCATED TO THIS AREA APPARENTLY AFTER THE END OF WINDMILL MANUFACTURE. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

14 CFR 25.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2010 CFR

2010-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first... two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the... axis. (d) Dihedral angle A (aft) is formed by two intersecting vertical planes making angles of 70...

14 CFR 27.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2010 CFR

2010-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first... two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and... longitudinal axis. (d) Dihedral angle A (aft) is formed by two intersecting vertical planes making angles of 70...

Windmills Are Going around Again

ERIC Educational Resources Information Center

Moyer, Richard H.; Everett, Susan A.

2011-01-01

Wind is reemerging as a clean and reliable source of energy--primarily for the production of electricity. This article discusses how to create a pinwheel to explore wind power. It presents a 5E learning-cycle lesson in which students construct a simple pinwheel-type windmill to test the power generated by different designs. Students compare three-…

"Happiness and Education": Tilting at Windmills?

ERIC Educational Resources Information Center

Verducci, Susan

2013-01-01

This essay explores the question: Is Nel Noddings a visionary who sees past the constraints of contemporary education or is she, like Don Quixote, madly tilting at windmills in her description and defense of happiness as an educational aim? Viewing the educational aim of happiness as an ideal raises substantial challenges for the practicality of…

Investigation of Spinning and Tumbling Characteristics of a 1/20-Scale Model of the Consolidated Vultee XFY-1 Airplane in the Free-Spinning Tunnel, TED No. NACA DE 370

NASA Technical Reports Server (NTRS)

Lee, Henry A.

1952-01-01

An investigation has been conducted in the Langley 20-foot free-spinning tunnel on a l/20-scale model of the Consolidated Vultee XFY-1 airplane with a windmilling propeller simulated to determine the effects of control setting and movements upon the erect spin and recovery characteristics for a range of airplane-loading conditions. The effects on the model's spin-recovery characteristics of removing the lower vertical tail, removing the gun pods, and fixing the rudders at neutral were also investigated briefly. The investigation included determination of the size parachute required for emergency recovery from demonstration spins. The tumbling tendencies of the model were also investigated. Brief static force tests were made to determine the aerodynamic characteristics in pitch at high angles of attack. The investigation indicated that the spin and recovery characteristics of the airplane with propeller windmilling will be satisfactory for all loading conditions if recovery is attempted by full rudder reversal accompanied by simultaneous movement of the stick laterally to full with the spin (stick right in a right spin) and longitudinally to neutral. Inverted spins should be satisfactorily terminated by fully reversing the rudder followed immediately by moving the stick laterally towards the forward rudder pedal and longitudinally to neutral. Removal of the gun pods or fixing the rudders at neutral will not adversely affect the airplane's spin-recovery characteristics, but removal of the lower vertical tail will result in unsatisfactory spin-recovery characteristics. The model-test results showed that a 13.3-foot wing-tip conventional parachute (drag coefficient approximately 0.7) should be effective as an emergency spin-recovery device during demonstration spins of the airplane. It was indicated that the airplane should not tumble and that no unusual longitudinal-trim characteristics should be obtained for the center-of-gravity positions investigated.

Pulse Power Hybrid Energy Storage Module Development Program

DTIC Science & Technology

2015-05-01

consumed by the PFN. The energy stored in the HESM is displayed 12 as flywheel speed (RPM) against the right-side vertical axis . The flywheel speed...energy consumed by the PFN. The energy stored in the HESM is shown in Joules on the left-side vertical axis and in terms of flywheel speed (RPM) on the...right-side vertical axis . A noticeable difference in the charging variants is seen in the energy transfer through the HESM. Referring to Fig. 8, the

Wind Energy Conference, Boulder, Colo., April 9-11, 1980, Technical Papers

NASA Astrophysics Data System (ADS)

1980-03-01

Papers are presented concerning the technology, and economics of wind energy conversion systems. Specific topics include the aerodynamic analysis of the Darrieus rotor, the numerical calculation of the flow near horizontal-axis wind turbine rotors, the calculation of dynamic wind turbine rotor loads, markets for wind energy systems, an oscillating-wing windmill, wind tunnel tests of wind rotors, wind turbine generator wakes, the application of a multi-speed electrical generator to wind turbines, the feasibility of wind-powered systems for dairy farms, and wind characteristics over uniform and complex terrain. Attention is also given to performance tests of the DOE/NASA MOD-1 2000-kW wind turbine generator, the assessment of utility-related test data, offshore wind energy conversion systems, and the optimization of wind energy utilization economics through load management.

X, Y, Z positioner

DOEpatents

Goers, G.F.

1987-11-10

A three-axis control for precisely and conveniently adjusting items such as mirrors and lenses is disclosed. The adjuster apparatus includes a vertical stack of three rotatable adjusters. Rotation of the first effects vertical translation, whereas the second and third are eccentric assemblies which interact to effect movement along two angled axes perpendicular to the vertical axis. 13 figs.

X, Y, Z positioner

DOEpatents

Goers, George F.

1987-01-01

A three-axis control for precisely and conveniently adjusting items such as irrors and lenses is disclosed. The adjuster apparatus includes a vertical stack of three rotatable adjusters. Rotation of the first effects vertical translation, whereas the second and third are eccentric assemblies which interact to effect movement along two angled axes perpendicular to the vertical axis.

14 CFR 29.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2010 CFR

2010-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the... formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft... longitudinal axis. (d) Dihedral angle A (aft) is formed by two intersecting vertical planes making angles of 70...

14 CFR 23.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2010 CFR

2010-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the... formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane... longitudinal axis. (d) Dihedral angle A (aft) is formed by two intersecting vertical planes making angles of 70...

Vertical axis wind turbines

DOEpatents

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

2011-03-08

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

Binocular Coordination of the Human Vestibulo-Ocular Reflex during Off-axis Pitch Rotation

NASA Technical Reports Server (NTRS)

Wood, S. J.; Reschke, M. F.; Kaufman, G. D.; Black, F. O.; Paloski, W. H.

2006-01-01

Head movements in the sagittal pitch plane typically involve off-axis rotation requiring both vertical and horizontal vergence ocular reflexes to compensate for angular and translational motion relative to visual targets of interest. The purpose of this study was to compare passive pitch VOR responses during rotation about an Earth-vertical axis (canal only cues) with off-axis rotation (canal and otolith cues). Methods. Eleven human subjects were oscillated sinusoidally at 0.13, 0.3 and 0.56 Hz while lying left-side down with the interaural axis either aligned with the axis of rotation or offset by 50 cm. In a second set of measurements, twelve subjects were also tested during sinusoidally varying centrifugation over the same frequency range. The modulation of vertical and horizontal vergence ocular responses was measured with a binocular videography system. Results. Off-axis pitch rotation enhanced the vertical VOR at lower frequencies and enhanced the vergence VOR at higher frequencies. During sinusoidally varying centrifugation, the opposite trend was observed for vergence, with both vertical and vergence vestibulo-ocular reflexes being suppressed at the highest frequency. Discussion. These differential effects of off-axis rotation over the 0.13 to 0.56 Hz range are consistent with the hypothesis that otolith-ocular reflexes are segregated in part on the basis of stimulus frequency. At the lower frequencies, tilt otolith-ocular responses compensate for declining canal input. At higher frequencies, translational otolith-ocular reflexes compensate for declining visual contributions to the kinematic demands required for fixating near targets.

Windmills by Design: Purposeful Curriculum Design to Meet Next Generation Science Standards in a 9-12 Physics Classroom

ERIC Educational Resources Information Center

Concannon, James; Brown, Patrick L.

2017-01-01

The "Next Generation Science Standards" (NGSS) challenges science teachers to think beyond specific content standards when considering how to design and implement curriculum. This lesson, "Windmills by Design," is an insightful lesson in how science teachers can create and implement a cross-cutting lesson to teach the concepts…

Tilting at Windmills: School Reform, San Diego, and America?s Race to Renew Public Education

ERIC Educational Resources Information Center

Colvin, Richard Lee

2013-01-01

A book that draws equally on Richard Lee Colvin's deep acquaintance with contemporary education reform and the unique circumstances of the San Diego experience, "Tilting at Windmills" is a penetrating and invaluable account of Alan Bersin's contentious superintendency. Between 1998, when Alan Bersin became superintendent of the San Diego…

Modular off-axis solar concentrator

DOEpatents

Plesniak, Adam P; Hall, John C

2015-01-27

A solar concentrator including a housing defining a vertical axis and including a receiving wall connected to a reflecting wall to define an internal volume and an opening into the internal volume, wherein the reflecting wall defines at least one primary optical element, and wherein at least a portion of the reflecting wall includes a layer of reflective material, the housing further including a cover connected to the receiving wall and the reflecting wall to seal the opening, and at least one receiver mounted on the receiving wall such that a vertical axis of the receiver is disposed at a non-zero angle relative to the vertical axis of the housing, the receiver including at least one photovoltaic cell.

An analytic model of the in-line and cross-axis apparent mass of the seated human body exposed to vertical vibration with and without a backrest

NASA Astrophysics Data System (ADS)

Zheng, Guangtai; Qiu, Yi; Griffin, Michael J.

2011-12-01

During vertical excitation of the seated human body there are vertical and fore-and-aft forces at the seat that are influenced by contact with a backrest, so it is desirable to take into account the effect of a backrest when developing models of the seated human body. Initially, a seven degree-of-freedom multi-body dynamic model was developed for the human body sitting with an upright posture unsupported by a backrest and exposed to vertical vibration. The model was optimized to fit the vertical apparent mass and the fore-and-aft cross-axis apparent mass measured on a seat. The model was then extended by the addition of vertical and fore-and-aft reaction forces to the upper lumbar spine to model the interaction between the human body and a backrest. By minimizing the least square error between experimental data and the analytical solution of the apparent masses on the seat and at the back, the human body model was able to represent both the vertical apparent mass and the fore-and-aft cross-axis apparent mass on the seat and at the back. Parameter sensitivity studies showed that the vertical apparent mass and the fore-and-aft cross-axis apparent mass on the seat and the backrest were all highly sensitive to the axial stiffness of the tissue beneath the pelvis. Pitch motion of the upper-body contributed to the vertical apparent mass and the fore-and-aft cross-axis apparent mass on the seat. The apparent mass at the back was more sensitive to the stiffness and damping of the lower back than the properties of the upper back.

Adaptive Changes in the Perception of Fast and Slow Movement at Different Head Positions.

PubMed

Panichi, Roberto; Occhigrossi, Chiara; Ferraresi, Aldo; Faralli, Mario; Lucertini, Marco; Pettorossi, Vito E

2017-05-01

This paper examines the subjective sense of orientation during asymmetric body rotations in normal subjects. Self-motion perception was investigated in 10 healthy individuals during asymmetric whole-body rotation with different head orientations. Both on-vertical axis and off-vertical axis rotations were employed. Subjects tracked a remembered earth-fixed visual target while rotating in the dark for four cycles of asymmetric rotation (two half-sinusoidal cycles of the same amplitude, but of different duration). The rotations induced a bias in the perception of velocity (more pronounced with fast than with slow motion). At the end of rotation, a marked target position error (TPE) was present. For the on-vertical axis rotations, the TPE was no different if the rotations were performed with a 30° nose-down, a 60° nose-up, or a 90° side-down head tilt. With off-vertical axis rotations, the simultaneous activation of the semicircular canals and otolithic receptors produced a significant increase of TPE for all head positions. This difference between on-vertical and off-vertical axis rotation was probably partly due to the vestibular transfer function and partly due to different adaptation to the speed of rotation. Such a phenomenon might be generated in different components of the vestibular system. The adaptive process enhancing the perception of dynamic movement around the vertical axis is not related to the specific semicircular canals that are activated; the addition of an otolithic component results in a significant increase of the TPE.Panichi R, Occhigrossi C, Ferraresi A, Faralli M, Lucertini M, Pettorossi VE. Adaptive changes in the perception of fast and slow movement at different head positions. Aerosp Med Hum Perform. 2017; 88(5):463-468.

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

NASA Astrophysics Data System (ADS)

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

2017-05-01

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

Softball Pitching and Injury.

PubMed

Lear, Aaron; Patel, Niraj

2016-01-01

The windmill softball pitch generates considerable forces about the athlete's shoulder and elbow. The injury pattern of softball pitchers seems to be primarily overuse injury, and they seem not to suffer the same volume of injury that baseball pitchers do. This article will explore softball pitching techniques, kinetics and kinematics of the windmill pitch, epidemiology of softball pitchers, and discuss possible etiologies of softball pitching injuries.

Three-dimensional organization of vestibular-related eye movements to off-vertical axis rotation and linear translation in pigeons

NASA Technical Reports Server (NTRS)

Dickman, J. D.; Angelaki, D. E.

1999-01-01

During linear accelerations, compensatory reflexes should continually occur in order to maintain objects of visual interest as stable images on the retina. In the present study, the three-dimensional organization of the vestibulo-ocular reflex in pigeons was quantitatively examined during linear accelerations produced by constant velocity off-vertical axis yaw rotations and translational motion in darkness. With off-vertical axis rotations, sinusoidally modulated eye-position and velocity responses were observed in all three components, with the vertical and torsional eye movements predominating the response. Peak torsional and vertical eye positions occurred when the head was oriented with the lateral visual axis of the right eye directed orthogonal to or aligned with the gravity vector, respectively. No steady-state horizontal nystagmus was obtained with any of the rotational velocities (8-58 degrees /s) tested. During translational motion, delivered along or perpendicular to the lateral visual axis, vertical and torsional eye movements were elicited. No significant horizontal eye movements were observed during lateral translation at frequencies up to 3 Hz. These responses suggest that, in pigeons, all linear accelerations generate eye movements that are compensatory to the direction of actual or perceived tilt of the head relative to gravity. In contrast, no translational horizontal eye movements, which are known to be compensatory to lateral translational motion in primates, were observed under the present experimental conditions.

The sail wing windmill and its adaptation for use in rural India

NASA Technical Reports Server (NTRS)

Sherman, M. M.

1973-01-01

An 8 meter-diameter prototype sail wing windmill is reported that uses a one meter-diameter bullock cartwheel to which three bamboo poles are latched in a triangular pattern with overlapping ends, to form the airframe for cloth sails. This device lifts 300 pounds to a height of 20 feet in one minute in a 10 mph wind.

45. WEST TO CIRCA 1900 SHEET METAL SHEAR, THE MACHINE ...

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

45. WEST TO CIRCA 1900 SHEET METAL SHEAR, THE MACHINE USED TO CUT SHEET METAL USED IN WINDMILLS AND WATER TANKS. IN THE BACKGROUND IS THE INTERIOR WEST WALL OF THE FACTORY, ITS SHELVES BEARING WATER PUMPS, PARTS FOR PUMPS AND WATER SUPPLY EQUIPMENT, AND NEW OLD STOCK MERCHANDISE. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

A scheiner-principle vernier optometer

NASA Astrophysics Data System (ADS)

Cushman, William B.

1989-06-01

A method and optometer apparatus is disclosed for measuring the dark focus of accommodation. In a preferred embodiment, the optometer apparatus includes: a pinhole aperture plate having first and second horizontally positioned apertures disposed on opposite sides of a first optical axis; first and second orthogonally-oriented polarizing filters respectively covering the first and second horizontally positioned apertures; a positive lens having an optical axis on the first optical axis and being positioned at a distance of approximately one focal length from the pinhole aperture plate; a lens system having an optical axis on the first optical axis; a slit aperture plate having a vertical slit and being disposed on the first optical axis and between the positive lens and the lens system; third and fourth vertically positioned polarizing filters selectively disposed adjacent to the slit aperture plate to divide the slit vertically, a monochromatic light source for propagating light along the first optical axis through the lens system; and movable means attached to the slit aperture plate, the lens system and the monochromatic light source for moving the slit aperture plate.

Research on the unsteady hydrodynamic characteristics of vertical axis tidal turbine

NASA Astrophysics Data System (ADS)

Zhang, Xue-wei; Zhang, Liang; Wang, Feng; Zhao, Dong-ya; Pang, Cheng-yan

2014-03-01

The unsteady hydrodynamic characteristics of vertical axis tidal turbine are investigated by numerical simulation based on viscous CFD method. The starting mechanism of the turbine is revealed through analyzing the interaction of its motion and dynamics during starting process. The operating hydrodynamic characteristics of the turbine in wave-current condition are also explored by combining with the linear wave theory. According to possible magnification of the cyclic loads in the maximum power tracking control of vertical axis turbine, a novel torque control strategy is put forward, which can improve the structural characteristics significantly without effecting energy efficiency.

Electrocardiographic screening for emphysema: the frontal plane P axis.

PubMed

Baljepally, R; Spodick, D H

1999-03-01

Because the most characteristic and sensitive electrocardiographic (ECG) correlate of pulmonary emphysema in adults is verticalization of the frontal plane P-wave vector (P axis), we investigated its strength as a lone criterion to screen for obstructive pulmonary disease (OPD) in an adult hospital population. In all, 954 consecutive unselected ECGs were required to yield 100 with P axis > or = +70 degrees (unequivocally negative P in a VL during sinus rhythm) and pulmonary function tests. and 100 with P axis < or = +50 degrees (unequivocally positive P-aVL). Obstructive pulmonary disease by both pulmonary function test and clinical criteria was present in 89 of 100 patients with vertical P axes and 4 of 100 patients without OPD. The high sensitivity (89% for this series) and high specificity (96%) makes vertical P axis a useful screening criterion. Its at-a-glance simplicity makes it "user-friendly."

Wind power. [electricity generation

NASA Technical Reports Server (NTRS)

Savino, J. M.

1975-01-01

A historical background on windmill use, the nature of wind, wind conversion system technology and requirements, the economics of wind power and comparisons with alternative systems, data needs, technology development needs, and an implementation plan for wind energy are presented. Considerable progress took place during the 1950's. Most of the modern windmills feature a wind turbine electricity generator located directly at the top of their rotor towers.

Preliminary Results of an Altitude-Wind-Tunnel Investigation of a TG-100A Gas Turbine-Propeller Engine II - Windmilling Characteristics

NASA Technical Reports Server (NTRS)

Conrad, E. W.; Durham, J. D.

1947-01-01

An investigation was conducted to determine the operational and performance characteristics of the TG-100A gas turbine-propeller engine II. Windmilling characteristics were deterined for a range of altitudes from 5000 to 35,000 feet, true airspeeds from 100 to 273 miles per hour, and propeller blade angles from 4 degrees to 46 degrees.

Preliminary Results of an Altitude-Wind-Tunnel Investigation of an Axial-Flow Gas Turbine-Propeller Engine. 2; Windmilling Characteristics

NASA Technical Reports Server (NTRS)

Conrad, E. W.; Durham, J. D.

1948-01-01

Wind tunnel investigations were performed to determine the performance properties of an axial-flow gas turbine-propeller engine II. Windmilling characteristics were determined for a range of altitudes from 5000 to 35,000 feet, true airspeeds from 100 to 273 miles per hour, and propeller blade angles from 4 degrees to 46 degrees.

Muscle activation patterns of the upper and lower extremity during the windmill softball pitch.

PubMed

Oliver, Gretchen D; Plummer, Hillary A; Keeley, David W

2011-06-01

Fast-pitch softball has become an increasingly popular sport for female athletes. There has been little research examining the windmill softball pitch in the literature. The purpose of this study was to describe the muscle activation patterns of 3 upper extremity muscles (biceps, triceps, and rhomboids [scapular stabilizers]) and 2 lower extremity muscles (gluteus maximus and medius) during the 5 phases of the windmill softball pitch. Data describing muscle activation were collected on 7 postpubescent softball pitchers (age 17.7 ± 2.6 years; height 169 ± 5.4 cm; mass 69.1 ± 5.4 kg). Surface electromyographic data were collected using a Myopac Jr 10-channel amplifier (RUN Technologies Scientific Systems, Laguna Hills, CA, USA) synchronized with The MotionMonitor™ motion capture system (Innovative Sports Training Inc, Chicago IL, USA) and presented as a percent of maximum voluntary isometric contraction. Gluteus maximus activity reached (196.3% maximum voluntary isometric contraction [MVIC]), whereas gluteus medius activity was consistent during the single leg support of phase 3 (101.2% MVIC). Biceps brachii activity was greatest during phase 4 of the pitching motion. Triceps brachii activation was consistently >150% MVIC throughout the entire pitching motion, whereas the scapular stabilizers were most active during phase 2 (170.1% MVIC). The results of this study indicate the extent to which muscles are activated during the windmill softball pitch, and this knowledge can lead to the development of proper preventative and rehabilitative muscle strengthening programs. In addition, clinicians will be able to incorporate strengthening exercises that mimic the timing of maximal muscle activation most used during the windmill pitching phases.

Tower wake/blade interaction noise of a wind turbine

NASA Astrophysics Data System (ADS)

Nishiwaki, Hideo; Takeda, Katsumi

1987-10-01

A scale model of a 1.5m dia. two-bladed windturbine was used in an anechoic chamber that provided a free-stream velocity of 8m/s. The blades used were a 1.5/8 scale model of a test machine for a local energy utilization project promoted by the Science and Technology Agency. The height of the tower from the ground level was 1.8m. The acoustic measurements were made in a circle of 1.6m downstream from the machine at the height of the windmill centerline. The noise level of the on-axis spectra was about 15dB larger than that of the off-axis. This is a result of the dipole nature of the acoustic impulse. The Wortmann airfoil (FX 77-W series) was employed for the blade profiles and the Reynolds number was 10(5), based on the tip chord length. The experiment revealed that the sound intensity at each harmonic was not proportional to the axial and radial extents of the wake. The elliptic slender configuration was the quietest, while the square configuration was the loudest. From a practical point of view, it is suggested that the circular section is most suitable for the tower leg.

Aircraft body-axis rotation measurement system

NASA Technical Reports Server (NTRS)

Cowdin, K. T. (Inventor)

1983-01-01

A two gyro four gimbal attitude sensing system having gimbal lock avoidance is provided with continuous azimuth information, rather than roll information, relative to the magnetic cardinal headings while in near vertical attitudes to allow recovery from vertical on a desired heading. The system is comprised of a means for stabilizing an outer roll gimbal that is common to a vertical gyro and a directional gyro with respect to the aircraft platform which is being angularly displaced about an axis substantially parallel to the outer roll gyro axis. A means is also provided for producing a signal indicative of the magnitude of such displacement as an indication of aircraft heading. Additional means are provided to cause stabilization of the outer roll gimbal whenever the pitch angle of the aircraft passes through a threshold prior to entering vertical flight and destabilization of the outer roll gimbal upon passing through the threshold when departing vertical flight.

Enclosed, off-axis solar concentrator

DOEpatents

Benitez, Pablo; Grip, Robert E; Minano, Juan C; Narayanan, Authi A; Plesniak, Adam; Schwartz, Joel A

2013-11-26

A solar concentrator including a housing having receiving wall, a reflecting wall and at least two end walls, the receiving, reflecting and end walls defining a three-dimensional volume having an inlet, wherein a vertical axis of the housing is generally perpendicular to the inlet, a receiver mounted on the receiving wall of the housing, the receiver including at least one photovoltaic cell, wherein a vertical axis of the receiver is disposed at a non-zero angle relative to the vertical axis of the housing, at least one clip disposed on the reflecting wall an optical element received within the three-dimensional volume, the optical element including at least one tab, the tab being engaged by the clip to align the optical element with the receiver, and a window received over the inlet to enclose the housing.

United in prevention-electrocardiographic screening for chronic obstructive pulmonary disease.

PubMed

Lazovic, Biljana; Mazic, Sanja; Stajic, Zoran; Djelic, Marina; Zlatkovic-Svenda, Mirjana; Putnikovic, Biljana

2013-01-01

NONE DECLARED. P-wave abnormalities on the resting electrocardiogram have been associated with cardiovascular or pulmonary disease. So far, "Gothic" P wave and verticalization of the frontal plane axis is related to lung disease, particularly obstructive lung disease. We tested if inverted P wave in AVl as a lone criteria of P wave axis >70° could be screening tool for emphysema. 1095 routine electrocardiograms (ECGs) were reviewed which yielded 478 (82,1%) ECGs with vertical P-axis in sinus rhythm. Charts were reviewed for the diagnosis of COPD and emphysema based on medical history and pulmonary function tests. Electrocardiogram is very effective screening tool not only in cardiovascular field but in chronic obstructive pulmonary disease. The verticality of the P axis is usually immediately apparent, making electrocardiogram rapid screening test for emphysema.

40 CFR 75.41 - Precision criteria.

Code of Federal Regulations, 2011 CFR

2011-07-01

... for the entire 30- to 90-day period. (9) The owner or operator shall provide two separate time series... time where the vertical axis represents the percentage difference between each paired hourly reading... monitoring system (or reference method) readings versus time where the vertical axis represents hourly...

40 CFR 75.41 - Precision criteria.

Code of Federal Regulations, 2014 CFR

2014-07-01

... for the entire 30- to 90-day period. (9) The owner or operator shall provide two separate time series... time where the vertical axis represents the percentage difference between each paired hourly reading... monitoring system (or reference method) readings versus time where the vertical axis represents hourly...

40 CFR 75.41 - Precision criteria.

Code of Federal Regulations, 2010 CFR

2010-07-01

... for the entire 30- to 90-day period. (9) The owner or operator shall provide two separate time series... time where the vertical axis represents the percentage difference between each paired hourly reading... monitoring system (or reference method) readings versus time where the vertical axis represents hourly...

40 CFR 75.41 - Precision criteria.

Code of Federal Regulations, 2013 CFR

2013-07-01

... for the entire 30- to 90-day period. (9) The owner or operator shall provide two separate time series... time where the vertical axis represents the percentage difference between each paired hourly reading... monitoring system (or reference method) readings versus time where the vertical axis represents hourly...

40 CFR 75.41 - Precision criteria.

Code of Federal Regulations, 2012 CFR

2012-07-01

... for the entire 30- to 90-day period. (9) The owner or operator shall provide two separate time series... time where the vertical axis represents the percentage difference between each paired hourly reading... monitoring system (or reference method) readings versus time where the vertical axis represents hourly...

The system design and performance test of hybrid vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Dwiyantoro, Bambang Arip; Suphandani, Vivien

2017-04-01

Vertical axis wind turbine is a tool that is being developed to generate energy from wind. One cause is still little use of wind energy is the design of wind turbines that are less precise. Therefore in this study will be developed the system design of hybrid vertical axis wind turbine and tested performance with experimental methods. The design of hybrid turbine based on a straight bladed Darrieus turbine along with a double step Savonius turbine. The method used to design wind turbines is by studying literature, analyzing the critical parts of a wind turbine and the structure of the optimal design. Wind turbine prototype of the optimal design characteristic tests in the wind tunnel experimentally by varying the speed of the wind. From the experimental results show that the greater the wind speed, the greater the wind turbine rotation and torque is raised. The hybrid vertical axis wind turbine has much better self-starting and better conversion efficiency.

51. WEST ACROSS CLUTTER TO WEST WALL OF WELLSERVICE SHED ...

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

51. WEST ACROSS CLUTTER TO WEST WALL OF WELL-SERVICE SHED ADDITION ON REAR OF FACTORY BUILDING. AT LOWER RIGHT FOREGROUND IS 1960S PICKUP TRUCK, THE LAST MOTOR VEHICLE USED IN WELL SERVICE BY THE KREGEL WINDMILL COMPANY. MOST OF THE OBJECTS VISIBLE IN THIS VIEW ARE CLUTTER NOT RELATED TO THE WELL SERVICE BUSINESS. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

Grassland Birds Wintering at U.S. Navy Facilities in Southern Texas

DTIC Science & Technology

2010-07-01

Cenchrus echinatus N X X Coastal sandbur Cenchrus spinifex N X X X Slimspike windmill grass Chloris andropogonoides N X Fringed windmill grass Chloris...Hatch, Texas A&M University. Additional scientific expertise was provided by Gene Blacklock and David Newstead, Coastal Bend Bays & Estuaries Program...Inland Prairies of Texas The study area was located in two Texas ecoregions. Coastal study sites were located in the Gulf Coast Prairies and Marshes

Horizontal EDNA miner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Justice, J.C.; Delli-Gatti, F.A.

1985-12-03

A mining machine is utilized for making original generally horizontal bores in coal seams, and for enlarging preexisting bores. A single cutting head is mounted for rotation about a first horizontal axis generally perpendicular to the dimension of elongation of the horizontal bore, and is pivotal about a second horizontal axis, parallel to the first axis, to change its cutting, vertical position within the bore. A non-rotatable body member, with side wall supports, is mounted posteriorly of the cutting head, and includes a conveyor mechanism and a power mechanism operatively connected to it. The machine can be sumped into amore » bore and then the cutting head rotated about the second axis to change the vertical position thereof, and then moved rearwardly, any cut material being continuously conveyed to the bore mouth by the conveyor mechanism. The amount of vertical movement during the pivoting action about the second axis is controlled in response to the automatic sensing of the thickness of the coal seam in which the machine operates.« less

The Kerala Decentration Meter. A new method and devise for fitting the optical of spectacle lenses in the visual axis.

PubMed

Joseph, T K; Kartha, C P

1982-01-01

Centring of spectacle lenses is much neglected field of ophthalmology. The prismatic effect caused by wrong centring results in a phoria on the eye muscles which in turn causes persistent eyestrain. The theory of visual axis, optical axis and angle alpha is discussed. Using new methods the visual axis and optical axis of 35 subjects were measured. The results were computed for facial asymmetry, parallax error, angle alpha and also decentration for near vision. The results show that decentration is required on account of each of these factors. Considerable correction is needed in the vertical direction, a fact much neglected nowadays; and vertical decentration results in vertical phoria which is more symptomatic than horizontal phorias. Angle Alpha was computed for each of these patients. A new devise called 'The Kerala Decentration Meter' using the pinhole method for measuring the degree of decentration from the datum centre of the frame, and capable of correcting all the factors described above, is shown with diagrams.

Alignment of x-ray tube focal spots for spectral measurement.

PubMed

Nishizawa, K; Maekoshi, H; Kamiya, Y; Kobayashi, Y; Ohara, K; Sakuma, S

1982-01-01

A general method to align a diagnostic x-ray machine for x-ray spectrum measurement purpose was theoretically and experimentally investigated by means of the optical alignment of focal pinhole images. Focal pinhole images were obtained by using a multi-pinholed lead plate. the vertical plane, including the central axis and tube axis, was decided upon by observing the symmetry of focal images. the central axis was designated as a line through the center of focus parallel to the target surface lying in the vertical plane. A method to determine the manipulation of the central axis in any direction is presented.

Three-dimensional organization of otolith-ocular reflexes in rhesus monkeys. II. Inertial detection of angular velocity

NASA Technical Reports Server (NTRS)

Angelaki, D. E.; Hess, B. J.

1996-01-01

1. The dynamic contribution of otolith signals to three-dimensional angular vestibuloocular reflex (VOR) was studied during off-vertical axis rotations in rhesus monkeys. In an attempt to separate response components to head velocity from those to head position relative to gravity during low-frequency sinusoidal oscillations, large oscillation amplitudes were chosen such that peak-to-peak head displacements exceeded 360 degrees. Because the waveforms of head position and velocity differed in shape and frequency content, the particular head position and angular velocity sensitivity of otolith-ocular responses could be independently assessed. 2. During both constant velocity rotation and low-frequency sinusoidal oscillations, the otolith system generated two different types of oculomotor responses: 1) modulation of three-dimensional eye position and/or eye velocity as a function of head position relative to gravity, as presented in the preceding paper, and 2) slow-phase eye velocity as a function of head angular velocity. These two types of otolith-ocular responses have been analyzed separately. In this paper we focus on the angular velocity responses of the otolith system. 3. During constant velocity off-vertical axis rotations, a steady-state nystagmus was elicited that was maintained throughout rotation. During low-frequency sinusoidal off-vertical axis oscillations, dynamic otolith stimulation resulted primarily in a reduction of phase leads that characterize low-frequency VOR during earth-vertical axis rotations. Both of these effects are the result of an internally generated head angular velocity signal of otolithic origin that is coupled through a low-pass filter to the VOR. No change in either VOR gain or phase was observed at stimulus frequencies larger than 0.1 Hz. 4. The dynamic otolith contribution to low-frequency angular VOR exhibited three-dimensional response characteristics with some quantitative differences in the different response components. For horizontal VOR, the amplitude of the steady-state slow-phase velocity during constant velocity rotation and the reduction of phase leads during sinusoidal oscillation were relatively independent of tilt angle (for angles larger than approximately 10 degrees). For vertical and torsional VOR, the amplitude of steady-state slow-phase eye velocity during constant velocity rotation increased, and the phase leads during sinusoidal oscillation decreased with increasing tilt angle. The largest steady-state response amplitudes and smallest phase leads were observed during vertical/torsional VOR about an earth-horizontal axis. 5. The dynamic range of otolith-borne head angular velocity information in the VOR was limited to velocities up to approximately 110 degrees/s. Higher head velocities resulted in saturation and a decrease in the amplitude of the steady-state response components during constant velocity rotation and in increased phase leads during sinusoidal oscillations. 6. The response characteristics of otolith-borne angular VORs were also studied in animals after selective semicircular canal inactivation. Otolith angular VORs exhibited clear low-pass filtered properties with a corner frequency of approximately 0.05-0.1 Hz. Vectorial summation of canal VOR alone (elicited during earth-vertical axis rotations) and otolith VOR alone (elicited during off-vertical axis oscillations after semicircular canal inactivation) could not predict VOR gain and phase during off-vertical axis rotations in intact animals. This suggests a more complex interaction of semicircular canal and otolith signals. 7. The results of this study show that the primate low-frequency enhancement of VOR dynamics during off-vertical axis rotation is independent of a simultaneous activation of the vertical and torsional "tilt" otolith-ocular reflexes that have been characterized in the preceding paper. (ABSTRACT TRUNCATED).

The application of hydraulics in the 2,000 kW wind turbine generator

NASA Technical Reports Server (NTRS)

Onufreiczuk, S.

1978-01-01

A 2000 kW turbine generator using hydraulic power in two of its control systems is being built under the management of NASA Lewis Research Center. The hydraulic systems providing the control torques and forces for the yaw and blade pitch control systems are discussed. The yaw-drive-system hydraulic supply provides the power for positioning the nacelle so that the rotary axis is kept in line with the direction of the prevailing wind, as well as pressure to the yaw and high speed shaft brakes. The pitch-change-mechanism hydraulic system provides the actuation to the pitch change mechanism and permits feathering of the blades during an emergency situation. It operates in conjunction with the overall windmill computer system, with the feather control permitting slewing control flow to pass from the servo valve to the actuators without restriction.

Targeted vertical cross-sectional imaging with handheld near-infrared dual axes confocal fluorescence endomicroscope.

PubMed

Qiu, Zhen; Liu, Zhongyao; Duan, Xiyu; Khondee, Supang; Joshi, Bishnu; Mandella, Michael J; Oldham, Kenn; Kurabayashi, Katsuo; Wang, Thomas D

2013-02-01

We demonstrate vertical cross-sectional (XZ-plane) images of near-infrared (NIR) fluorescence with a handheld dual axes confocal endomicroscope that reveals specific binding of a Cy5.5-labeled peptide to pre-malignant colonic mucosa. This view is perpendicular to the tissue surface, and is similar to that used by pathologists. The scan head is 10 mm in outer diameter (OD), and integrates a one dimensional (1-D) microelectromechanical systems (MEMS) X-axis scanner and a bulky lead zirconate titanate (PZT) based Z-axis actuator. The microscope images in a raster-scanning pattern with a ±6 degrees (mechanical) scan angle at ~3 kHz in the X-axis (fast) and up to 10 Hz (0-400 μm) in the Z-axis (slow). Vertical cross-sectional fluorescence images are collected with a transverse and axial resolution of 4 and 5 μm, respectively, over a field-of-view of 800 μm (width) × 400 μm (depth). NIR vertical cross-sectional fluorescence images of fresh mouse colonic mucosa demonstrate histology-like imaging performance with this miniature instrument.

Targeted vertical cross-sectional imaging with handheld near-infrared dual axes confocal fluorescence endomicroscope

PubMed Central

Qiu, Zhen; Liu, Zhongyao; Duan, Xiyu; Khondee, Supang; Joshi, Bishnu; Mandella, Michael J.; Oldham, Kenn; Kurabayashi, Katsuo; Wang, Thomas D.

2013-01-01

We demonstrate vertical cross-sectional (XZ-plane) images of near-infrared (NIR) fluorescence with a handheld dual axes confocal endomicroscope that reveals specific binding of a Cy5.5-labeled peptide to pre-malignant colonic mucosa. This view is perpendicular to the tissue surface, and is similar to that used by pathologists. The scan head is 10 mm in outer diameter (OD), and integrates a one dimensional (1-D) microelectromechanical systems (MEMS) X-axis scanner and a bulky lead zirconate titanate (PZT) based Z-axis actuator. The microscope images in a raster-scanning pattern with a ±6 degrees (mechanical) scan angle at ~3 kHz in the X-axis (fast) and up to 10 Hz (0–400 μm) in the Z-axis (slow). Vertical cross-sectional fluorescence images are collected with a transverse and axial resolution of 4 and 5 μm, respectively, over a field-of-view of 800 μm (width) × 400 μm (depth). NIR vertical cross-sectional fluorescence images of fresh mouse colonic mucosa demonstrate histology-like imaging performance with this miniature instrument. PMID:23412564

Vortex-augmented cooling tower-windmill combination

DOEpatents

McAllister, Jr., John E.

1985-01-01

A cooling tower for cooling large quantities of effluent water from a production facility by utilizing natural wind forces includes the use of a series of helically directed air inlet passages extending outwardly from the base of the tower to introduce air from any direction in a swirling vortical pattern while the force of the draft created in the tower makes it possible to place conventional power generating windmills in the air passages to provide power as a by-product.

Wind speed statistics for Goldstone, California, anemometer sites

NASA Technical Reports Server (NTRS)

Berg, M.; Levy, R.; Mcginness, H.; Strain, D.

1981-01-01

An exploratory wind survey at an antenna complex was summarized statistically for application to future windmill designs. Data were collected at six locations from a total of 10 anemometers. Statistics include means, standard deviations, cubes, pattern factors, correlation coefficients, and exponents for power law profile of wind speed. Curves presented include: mean monthly wind speeds, moving averages, and diurnal variation patterns. It is concluded that three of the locations have sufficiently strong winds to justify consideration for windmill sites.

Vortex-augmented cooling tower - windmill combination

DOEpatents

McAllister, J.E. Jr.

1982-09-02

A cooling tower for cooling large quantities of effluent water from a production facility by utilizing natural wind forces includes the use of a series of helically directed air inlet passages extending outwardly from the base of the tower to introduce air from any direction in a swirling vortical pattern while the force of the draft created in the tower makes it possible to place conventional power generating windmills in the air passage to provide power as a by-product.

Kinematics and kinetics of elite windmill softball pitching.

PubMed

Werner, Sherry L; Jones, Deryk G; Guido, John A; Brunet, Michael E

2006-04-01

A significant number of time-loss injuries to the upper extremity in elite windmill softball pitchers has been documented. The number of outings and pitches thrown in 1 week for a softball pitcher is typically far in excess of those seen in baseball pitchers. Shoulder stress in professional baseball pitching has been reported to be high and has been linked to pitching injuries. Shoulder distraction has not been studied in an elite softball pitching population. The stresses on the throwing shoulder of elite windmill pitchers are similar to those found for professional baseball pitchers. Descriptive laboratory study. Three-dimensional, high-speed (120 Hz) video data were collected on rise balls from 24 elite softball pitchers during the 1996 Olympic Games. Kinematic parameters related to pitching mechanics and resultant kinetics on the throwing shoulder were calculated. Multiple linear regression analysis was used to relate shoulder stress and pitching mechanics. Shoulder distraction stress averaged 80% of body weight for the Olympic pitchers. Sixty-nine percent of the variability in shoulder distraction can be explained by a combination of 7 parameters related to pitching mechanics. Excessive distraction stress at the throwing shoulder is similar to that found in baseball pitchers, which suggests that windmill softball pitchers are at risk for overuse injuries. Normative information regarding upper extremity kinematics and kinetics for elite softball pitchers has been established.

United in Prevention–Electrocardiographic Screening for Chronic Obstructive Pulmonary Disease

PubMed Central

Mazic, Sanja; Stajic, Zoran; Djelic, Marina; Zlatkovic-Svenda, Mirjana; Putnikovic, Biljana

2013-01-01

CONFLICT OF INTEREST: NONE DECLARED Introduction P-wave abnormalities on the resting electrocardiogram have been associated with cardiovascular or pulmonary disease. So far, “Gothic” P wave and verticalization of the frontal plane axis is related to lung disease, particularly obstructive lung disease. Aim We tested if inverted P wave in AVl as a lone criteria of P wave axis >70° could be screening tool for emphysema. Material and method 1095 routine electrocardiograms (ECGs) were reviewed which yielded 478 (82,1%) ECGs with vertical P-axis in sinus rhythm. Charts were reviewed for the diagnosis of COPD and emphysema based on medical history and pulmonary function tests. Conclusion Electrocardiogram is very effective screening tool not only in cardiovascular field but in chronic obstructive pulmonary disease. The verticality of the P axis is usually immediately apparent, making electrocardiogram rapid screening test for emphysema. PMID:24058253

Evaluation of simulation motion fidelity criteria in the vertical and directional axes

NASA Technical Reports Server (NTRS)

Schroeder, Jeffery A.

1993-01-01

An evaluation of existing motion fidelity criteria was conducted on the NASA Ames Vertical Motion Simulator. Experienced test pilots flew single-axis repositioning tasks in both the vertical and the directional axes. Using a first-order approximation of a hovering helicopter, tasks were flown with variations only in the filters that attenuate the commands to the simulator motion system. These filters had second-order high-pass characteristics, and the variations were made in the filter gain and natural frequency. The variations spanned motion response characteristics from nearly full math-model motion to fixed-base. Between configurations, pilots recalibrated their motion response perception by flying the task with full motion. Pilots subjectively rated the motion fidelity of subsequent configurations relative to this full motion case, which was considered the standard for comparison. The results suggested that the existing vertical-axis criterion was accurate for combinations of gain and natural frequency changes. However, if only the gain or the natural frequency was changed, the rated motion fidelity was better than the criterion predicted. In the vertical axis, the objective and subjective results indicated that a larger gain reduction was tolerated than the existing criterion allowed. The limited data collected in the yaw axis revealed that pilots had difficulty in distinguishing among the variations in the pure yaw motion cues.

A new vertical axis wind turbine design for urban areas

NASA Astrophysics Data System (ADS)

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

2016-06-01

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

Laser device

DOEpatents

Scott, Jill R.; Tremblay, Paul L.

2008-08-19

A laser device includes a virtual source configured to aim laser energy that originates from a true source. The virtual source has a vertical rotational axis during vertical motion of the virtual source and the vertical axis passes through an exit point from which the laser energy emanates independent of virtual source position. The emanating laser energy is collinear with an orientation line. The laser device includes a virtual source manipulation mechanism that positions the virtual source. The manipulation mechanism has a center of lateral pivot approximately coincident with a lateral index and a center of vertical pivot approximately coincident with a vertical index. The vertical index and lateral index intersect at an index origin. The virtual source and manipulation mechanism auto align the orientation line through the index origin during virtual source motion.

Machine imparting complex rotary motion for lapping a spherical inner diameter

DOEpatents

Carroll, Thomas A.; Yetter, Harold H.

1986-01-01

An apparatus for imparting complex rotary motion is used to lap an inner spherical diameter surface of a workpiece. A lapping tool consists of a dome and rod mounted along the dome's vertical axis. The workpiece containing the lapping tool is held in a gimbal which uses power derived from a secondary takeoff means to impart rotary motion about a horizontal axis. The gimbal is rotated about a vertical axis by a take means while mounted at a radially outward position on a rotating arm.

Development of Vault Toilet Waste Treatment Systems.

DTIC Science & Technology

1978-06-01

wi nd turbine used was a Savoniut’ Wing Rotor, a vertical axis rotor developed by S. J. Savonius in the early 1920’s and used exten- sively in the...2 ) i t was a vertical axis turbine which minimi zed tower con- struction costs, and (3) its high starting torque made it wel l suited to ariving an...ihe turbine constructed by this investigation consistea of two rotors, each 4 ft (1.2 m) high and 7 ft (2.1 m) in wi ath across the long axis , mounted

Machine imparting complex rotary motion for lapping a spherical inner diameter

DOEpatents

Carroll, T.A.; Yetter, H.H.

1985-01-30

An apparatus for imparting complex rotary motion is used to lap an inner spherical diameter surface of a workpiece. A lapping tool consists of a dome and rod mounted along the dome's vertical axis. The workpiece containing the lapping tool is held in a gimbal which uses power derived from a secondary takeoff means to impart rotary motion about a horizontal axis. The gimbal is rotated about a vertical axis by a take means while mounted at a radially outward position on a rotating arm.

Kinesthetic perceptions of earth- and body-fixed axes.

PubMed

Darling, W G; Hondzinski, J M

1999-06-01

The major purpose of this research was to determine whether kinesthetic/proprioceptive perceptions of the earth-fixed vertical axis are more accurate than perceptions of intrinsic axes. In one experiment, accuracy of alignment of the forearm to earth-fixed vertical and head- and trunk-longitudinal axes by seven blindfolded subjects was compared in four tasks: (1) Earth-Arm--arm (humerus) orientation was manipulated by the experimenter; subjects aligned the forearm parallel to the vertical axis, which was also aligned with the head and trunk longitudinal axis; (2) Head--head, trunk, and upper-limb orientations were manipulated by the experimenter, subjects aligned the forearm parallel to the longitudinal axis of the head using only elbow flexion/extension and shoulder internal/external rotation; (3) Trunk--same as (2), except that subjects aligned the forearm parallel to the trunk-longitudinal axis; (4) Earth--same as (2), except that subjects aligned the forearm parallel to the earth-fixed vertical. Head, trunk, and gravitational axes were never parallel in tasks 2, 3, and 4 so that subjects could not simultaneously match their forearm to all three axes. The results showed that the errors for alignment of the forearm with the earth-fixed vertical were lower than for the trunk- and head-longitudinal axes. Furthermore, errors in the Earth condition were less dependent on alterations of the head and trunk orientation than in the Head and Trunk conditions. These data strongly suggest that the earth-fixed vertical is used as one axis for the kinesthetic sensory coordinate system that specifies upper-limb orientation at the perceptual level. We also examined the effects of varying gravitational torques at the elbow and shoulder on the accuracy of forearm alignment to earth-fixed axes. Adding a 450 g load to the forearm to increase gravitational torques when the forearm is not vertical did not improve the accuracy of forearm alignment with the vertical. Furthermore, adding small, variably sized loads (between which the subjects could not distinguish at the perceptual level) to the forearm just proximal to the wrist produced similar errors in aligning the forearm with the vertical and horizontal. Forearm-positioning errors were not correlated with the size of the load, as would be expected if gravitational torques affected forearm-position sense. We conclude that gravitational torques exerted about the shoulder and elbow do not make significant contributions to sensing forearm-orientation relative to earth-fixed axes when the upper-limb segments are not constrained by external supports.

Three-Axis Ground Reaction Force Distribution during Straight Walking.

PubMed

Hori, Masataka; Nakai, Akihito; Shimoyama, Isao

2017-10-24

We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.

Lateral Stability Characteristics of a 1/8.33-Scale Powered Model of the Republic XF-12 Airplane

NASA Technical Reports Server (NTRS)

Pepper, Edward; Foster, Gerald V.

1947-01-01

The XF-12 airplane is a high-performance photo-reconnaissance aircraft designed for the Army Air Forces by the Republic Aviation Corporation. An investigation of a 1/8.33 - scale powered model was made in the Langley l9-foot pressure tunnel to obtain information relative to the aerodynamic design of the airplane. The model was tested with and without the original vertical tail. and with two revised tails. For the revised tail no. 1, the span of the original vertical .tail was increased about 15 percent and the portion of the vertical tail between the stabilizer and fuselage behind the rudder hinge line was allowed to deflect simultaneously with the main rudder. Revision no. 2 incorporated the increased span, but the lower rudder was locked in the neutral position. For all the tail arrangements investigated it was indicated that the airplane will possess positive effective dihedral and will be directionally stable regardless of flap or power condition. The rudder effectiveness is greater for the revised tails than for the original tail, but this is offset by the increase in directional stability caused by the revised tail. All the rudder arrangements appear inadequate in trimming out the resultant yawing moments at zero yaw in a take - off condition with the left-hand outboard propeller windmilling and the remaining engines developing take-off power.

P-wave indices in patients with pulmonary emphysema: do P-terminal force and interatrial block have confounding effects?

PubMed

Chhabra, Lovely; Chaubey, Vinod K; Kothagundla, Chandrasekhar; Bajaj, Rishi; Kaul, Sudesh; Spodick, David H

2013-01-01

Pulmonary emphysema causes several electrocardiogram changes, and one of the most common and well known is on the frontal P-wave axis. P-axis verticalization (P-axis > 60°) serves as a quasidiagnostic indicator of emphysema. The correlation of P-axis verticalization with the radiological severity of emphysema and severity of chronic obstructive lung function have been previously investigated and well described in the literature. However, the correlation of P-axis verticalization in emphysema with other P-indices like P-terminal force in V1 (Ptf), amplitude of initial positive component of P-waves in V1 (i-PV1), and interatrial block (IAB) have not been well studied. Our current study was undertaken to investigate the effects of emphysema on these P-wave indices in correlation with the verticalization of the P-vector. Unselected, routinely recorded electrocardiograms of 170 hospitalized emphysema patients were studied. Significant Ptf (s-Ptf) was considered ≥40 mm.ms and was divided into two types based on the morphology of P-waves in V1: either a totally negative (-) P wave in V1 or a biphasic (+/-) P wave in V1. s-Ptf correlated better with vertical P-vectors than nonvertical P-vectors (P = 0.03). s-Ptf also significantly correlated with IAB (P = 0.001); however, IAB and P-vector verticalization did not appear to have any significant correlation (P = 0.23). There was a very weak correlation between i-PV1 and frontal P-vector (r = 0.15; P = 0.047); however, no significant correlation was found between i-PV1 and P-amplitude in lead III (r = 0.07; P = 0.36). We conclude that increased P-tf in emphysema may be due to downward right atrial position caused by right atrial displacement, and thus the common assumption that increased P-tf implies left atrial enlargement should be made with caution in patients with emphysema. Also, the lack of strong correlation between i-PV1 and P-amplitude in lead III or vertical P-vector may suggest the predominant role of downward right atrial distortion rather than right atrial enlargement in causing vertical P-vector in emphysema.

Hatching success of ostrich eggs in relation to setting, turning and angle of rotation.

PubMed

van Schalkwyk, S J; Cloete, S W; Brown, C R; Brand, Z

2000-03-01

1. Three trials were designed to study the effects of axis of setting, turning frequency and axis and angle of rotation on the hatching success of ostrich eggs. The joint effects of axis of setting and angle of rotation were investigated in a fourth trial. 2. The hatchability of fertile ostrich eggs artificially incubated in electronic incubators (turned through 60 degrees hourly) was improved substantially in eggs set in horizontal positions for 2 or 3 weeks and vertically for the rest of the time. 3. The hatchability of fertile eggs set in the horizontal position without any turning was very low (27%). It was improved to approximately 60% by manual turning through 180 degrees around the short axis and through 60 degrees around the long axis at 08.00 and 16.00 h. A further improvement to approximately 80% was obtained in eggs automatically turned through 60 degrees around the long axis in the incubator. Additional turning through 180 degrees around the short axis twice daily at 08.00 and 16.00 h resulted in no further improvement. 4. The hatchability of fertile eggs set vertically in electronic incubators and rotated hourly through angles ranging from 60 degrees to 90 degrees around the short axis increased linearly over the range studied. The response amounted to 1.83% for an increase of 10 (R2=0.96). 5. The detrimental effect of rotation through the smaller angle of 60 degrees around the short axis could be compensated for by setting ostrich eggs in the horizontal position for 2 weeks before putting them in the vertical position.

Three-dimensional organization of otolith-ocular reflexes in rhesus monkeys. I. Linear acceleration responses during off-vertical axis rotation

NASA Technical Reports Server (NTRS)

Angelaki, D. E.; Hess, B. J.

1996-01-01

1. The dynamic properties of otolith-ocular reflexes elicited by sinusoidal linear acceleration along the three cardinal head axes were studied during off-vertical axis rotations in rhesus monkeys. As the head rotates in space at constant velocity about an off-vertical axis, otolith-ocular reflexes are elicited in response to the sinusoidally varying linear acceleration (gravity) components along the interaural, nasooccipital, or vertical head axis. Because the frequency of these sinusoidal stimuli is proportional to the velocity of rotation, rotation at low and moderately fast speeds allows the study of the mid-and low-frequency dynamics of these otolith-ocular reflexes. 2. Animals were rotated in complete darkness in the yaw, pitch, and roll planes at velocities ranging between 7.4 and 184 degrees/s. Accordingly, otolith-ocular reflexes (manifested as sinusoidal modulations in eye position and/or slow-phase eye velocity) were quantitatively studied for stimulus frequencies ranging between 0.02 and 0.51 Hz. During yaw and roll rotation, torsional, vertical, and horizontal slow-phase eye velocity was sinusoidally modulated as a function of head position. The amplitudes of these responses were symmetric for rotations in opposite directions. In contrast, mainly vertical slow-phase eye velocity was modulated during pitch rotation. This modulation was asymmetric for rotations in opposite direction. 3. Each of these response components in a given rotation plane could be associated with an otolith-ocular response vector whose sensitivity, temporal phase, and spatial orientation were estimated on the basis of the amplitude and phase of sinusoidal modulations during both directions of rotation. Based on this analysis, which was performed either for slow-phase eye velocity alone or for total eye excursion (including both slow and fast eye movements), two distinct response patterns were observed: 1) response vectors with pronounced dynamics and spatial/temporal properties that could be characterized as the low-frequency range of "translational" otolith-ocular reflexes; and 2) response vectors associated with an eye position modulation in phase with head position ("tilt" otolith-ocular reflexes). 4. The responses associated with two otolith-ocular vectors with pronounced dynamics consisted of horizontal eye movements evoked as a function of gravity along the interaural axis and vertical eye movements elicited as a function of gravity along the vertical head axis. Both responses were characterized by a slow-phase eye velocity sensitivity that increased three- to five-fold and large phase changes of approximately 100-180 degrees between 0.02 and 0.51 Hz. These dynamic properties could suggest nontraditional temporal processing in utriculoocular and sacculoocular pathways, possibly involving spatiotemporal otolith-ocular interactions. 5. The two otolith-ocular vectors associated with eye position responses in phase with head position (tilt otolith-ocular reflexes) consisted of torsional eye movements in response to gravity along the interaural axis, and vertical eye movements in response to gravity along the nasooccipital head axis. These otolith-ocular responses did not result from an otolithic effect on slow eye movements alone. Particularly at high frequencies (i.e., high speed rotations), saccades were responsible for most of the modulation of torsional and vertical eye position, which was relatively large (on average +/- 8-10 degrees/g) and remained independent of frequency. Such reflex dynamics can be simulated by a direct coupling of primary otolith afferent inputs to the oculomotor plant. (ABSTRACT TRUNCATED).

29. SOUTHEAST ACROSS BLACKSMITH SHOP AREA TOWARD TWO CIRCA 1900 ...

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

29. SOUTHEAST ACROSS BLACKSMITH SHOP AREA TOWARD TWO CIRCA 1900 DRILL PRESSES ALONG THE EAST INTERIOR WALL AT THE NORTHEAST CORNER OF THE FACTORY BUILDING. THE HOODED FORGE IS VISIBLE IN THE LEFT FOREGROUND, SHOWING LADLES USED FOR POURING BABBITT BEARINGS. MOUNTED ON THE WORK BENCH IS THE MAIN CASTING FROM AN ELI WINDMILL, USED AS A JIG TO SUPPORT PARTS DURING THE BABBITT BEARING POURING OPERATION. THE WALL ABOVE THE WORKBENCH SHOWS THE BOARDED-UP OPENING FOR A FORMER WINDOW. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

Developments in blade shape design for a Darrieus vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Ashwill, T. D.; Leonard, T. M.

1986-09-01

A new computer program package has been developed that determines the troposkein shape for a Darrieus Vertical Axis Wind Turbine Blade with any geometrical configuration or rotation rate. This package allows users to interact and develop a buildable blade whose shape closely approximates the troposkein. Use of this package can significantly reduce flatwise mean bending stresses in the blade and increase fatigue life.

Recent Darrieus vertical axis wind turbine aerodynamical experiments at Sandia National Laboratories

NASA Technical Reports Server (NTRS)

Klimas, P. C.

1981-01-01

Experiments contributing to the understanding of the aerodynamics of airfoils operating in the vertical axis wind turbine (VAWT) environment are described. These experiments are ultimately intended to reduce VAWT cost of energy and increase system reliability. They include chordwise pressure surveys, circumferential blade acceleration surveys, effects of blade camber, pitch and offset, blade blowing, and use of sections designed specifically for VAWT application.

A Large-eddy Simulation Study of Vertical Axis Wind Turbine Wakes in the Atmospheric Boundary Layer

NASA Astrophysics Data System (ADS)

Shamsoddin, Sina; Porté-Agel, Fernando

2016-04-01

Vertical axis wind turbines (VAWTs) offer some advantages over their horizontal axis counterparts, and are being considered as a viable alternative to conventional horizontal axis wind turbines (HAWTs). Nevertheless, a relative shortage of scientific, academic and technical investigations of VAWTs is observed in the wind energy community with respect to HAWTs. Having this in mind, in this work, we aim to study the wake of a single VAWT, placed in the atmospheric boundary layer, using large-eddy simulation (LES) coupled with actuator line model (ALM). It is noteworthy that this is the first time that such a study is being performed. To do this, for a typical 1 MW VAWT design, first, the variation of power coefficient with both the chord length of the blades and the tip-speed ratio is analyzed using LES-ALM, and an optimum combination of chord length and tip-speed ratio is obtained. Subsequently, the wake of a VAWT with these optimum specifications is thoroughly examined by showing different relevant mean and turbulent wake flow statistics. Keywords: vertical axis wind turbine (VAWT); VAWT wake; Atmospheric Boundary Layer (ABL); large eddy simulation (LES); actuator line model (ALM); turbulence.

Integrated Medical Curriculum: Advantages and Disadvantages

PubMed Central

Quintero, Gustavo A.; Vergel, John; Arredondo, Martha; Ariza, María-Cristina; Gómez, Paula; Pinzon-Barrios, Ana-Maria

2016-01-01

Most curricula for medical education have been integrated horizontally and vertically–-vertically between basic and clinical sciences. The Flexnerian curriculum has disappeared to permit integration between basic sciences and clinical sciences, which are taught throughout the curriculum. We have proposed a different form of integration where the horizontal axis represents the defined learning outcomes and the vertical axis represents the teaching of the sciences throughout the courses. We believe that a mere integration of basic and clinical sciences is not enough because it is necessary to emphasize the importance of humanism as well as health population sciences in medicine. It is necessary to integrate basic and clinical sciences, humanism, and health population in the vertical axis, not only in the early years but also throughout the curriculum, presupposing the use of active teaching methods based on problems or cases in small groups. PMID:29349303

Responses of neurons in the medial column of the inferior olive in pigeons to translational and rotational optic flowfields.

PubMed

Winship, I R; Wylie, D R

2001-11-01

The responses of neurons in the medial column of the inferior olive to translational and rotational optic flow were recorded from anaesthetized pigeons. Panoramic translational or rotational flowfields were produced by mechanical devices that projected optic flow patterns onto the walls, ceiling and floor of the room. The axis of rotation/translation could be positioned to any orientation in three-dimensional space such that axis tuning could be determined. Each neuron was assigned a vector representing the axis about/along which the animal would rotate/translate to produce the flowfield that elicited maximal modulation. Both translation-sensitive and rotation-sensitive neurons were found. For neurons responsive to translational optic flow, the preferred axis is described with reference to a standard right-handed coordinate system, where +x, +y and +z represent rightward, upward and forward translation of the animal, respectively (assuming that all recordings were from the right side of the brain). t(+y) neurons were maximally excited in response to a translational optic flowfield that results from self-translation upward along the vertical (y) axis. t(-y) neurons also responded best to translational optic flow along the vertical axis but showed the opposite direction preference. The two remaining groups, t(-x+z) and t(-x-z) neurons, responded best to translational optic flow along horizontal axes that were oriented 45 degrees to the midline. There were two types of neurons responsive to rotational optic flow: rVA neurons preferred rotation about the vertical axis, and rH135c neurons preferred rotation about a horizontal axis at 135 degrees contralateral azimuth. The locations of marking lesions indicated a clear topographical organization of the six response types. In summary, our results reinforce that the olivo-cerebellar system dedicated to the analysis of optic flow is organized according to a reference frame consisting of three approximately orthogonal axes: the vertical axis, and two horizontal axes oriented 45 degrees to either side the midline. Previous research has shown that the eye muscles, vestibular semicircular canals and postural control system all share a similar spatial frame of reference.

Double-multiple streamtube model for studying vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Paraschivoiu, Ion

1988-08-01

This work describes the present state-of-the-art in double-multiple streamtube method for modeling the Darrieus-type vertical-axis wind turbine (VAWT). Comparisons of the analytical results with the other predictions and available experimental data show a good agreement. This method, which incorporates dynamic-stall and secondary effects, can be used for generating a suitable aerodynamic-load model for structural design analysis of the Darrieus rotor.

PHLUX: Photographic Flux Tools for Solar Glare and Flux

DOE Office of Scientific and Technical Information (OSTI.GOV)

2010-12-02

A web-based tool to a) analytically and empirically quantify glare from reflected light and determine the potential impact (e.g., temporary flash blindness, retinal burn), and b) produce flux maps for central receivers. The tool accepts RAW digital photographs of the glare source (for hazard assessment) or the receiver (for flux mapping), as well as a photograph of the sun for intensity and size scaling. For glare hazard assessment, the tool determines the retinal irradiance (W/cm2) and subtended source angle for an observer and plots the glare source on a hazard spectrum (i.e., low-potential for flash blindness impact, potential for flashmore » blindness impact, retinal burn). For flux mapping, the tool provides a colored map of the receiver scaled by incident solar flux (W/m2) and unwraps the physical dimensions of the receiver while accounting for the perspective of the photographer (e.g., for a flux map of a cylindrical receiver, the horizontal axis denotes receiver angle in degrees and the vertical axis denotes vertical position in meters; for a flat panel receiver, the horizontal axis denotes horizontal position in meters and the vertical axis denotes vertical position in meters). The flux mapping capability also allows the user to specify transects along which the program plots incident solar flux on the receiver.« less

A Free Wake Numerical Simulation for Darrieus Vertical Axis Wind Turbine Performance Prediction

NASA Astrophysics Data System (ADS)

Belu, Radian

2010-11-01

In the last four decades, several aerodynamic prediction models have been formulated for the Darrieus wind turbine performances and characteristics. We can identified two families: stream-tube and vortex. The paper presents a simplified numerical techniques for simulating vertical axis wind turbine flow, based on the lifting line theory and a free vortex wake model, including dynamic stall effects for predicting the performances of a 3-D vertical axis wind turbine. A vortex model is used in which the wake is composed of trailing stream-wise and shedding span-wise vortices, whose strengths are equal to the change in the bound vortex strength as required by the Helmholz and Kelvin theorems. Performance parameters are computed by application of the Biot-Savart law along with the Kutta-Jukowski theorem and a semi-empirical stall model. We tested the developed model with an adaptation of the earlier multiple stream-tube performance prediction model for the Darrieus turbines. Predictions by using our method are shown to compare favorably with existing experimental data and the outputs of other numerical models. The method can predict accurately the local and global performances of a vertical axis wind turbine, and can be used in the design and optimization of wind turbines for built environment applications.

Do humans show velocity-storage in the vertical rVOR?

PubMed

Bertolini, G; Bockisch, C J; Straumann, D; Zee, D S; Ramat, S

2008-01-01

To investigate the contribution of the vestibular velocity-storage mechanism (VSM) to the vertical rotational vestibulo-ocular reflex (rVOR) we recorded eye movements evoked by off-vertical axis rotation (OVAR) using whole-body constant-velocity pitch rotations about an earth-horizontal, interaural axis in four healthy human subjects. Subjects were tumbled forward, and backward, at 60 deg/s for over 1 min using a 3D turntable. Slow-phase velocity (SPV) responses were similar to the horizontal responses elicited by OVAR along the body longitudinal axis, ('barbecue' rotation), with exponentially decaying amplitudes and a residual, otolith-driven sinusoidal response with a bias. The time constants of the vertical SPV ranged from 6 to 9 s. These values are closer to those that reflect the dynamic properties of vestibular afferents than the typical 20 s produced by the VSM in the horizontal plane, confirming the relatively smaller contribution of the VSM to these vertical responses. Our preliminary results also agree with the idea that the VSM velocity response aligns with the direction of gravity. The horizontal and torsional eye velocity traces were also sinusoidally modulated by the change in gravity, but showed no exponential decay.

Design of a magnetic force exciter for a small-scale windmill using a piezo-composite generating element

NASA Astrophysics Data System (ADS)

Luong, Hung Truyen; Goo, Nam Seo

2011-03-01

We introduce a design for a magnetic force exciter that applies vibration to a piezo-composite generating element (PCGE) for a small-scale windmill to convert wind energy into electrical energy. The windmill can be used to harvest wind energy in urban regions. The magnetic force exciter consists of exciting magnets attached to the device's input rotor, and a secondary magnet that is fixed at the tip of the PCGE. Under an applied wind force, the input rotor rotates to create a magnetic force interaction to excite the PCGE. Deformation of the PCGE enables it to generate the electric power. Experiments were performed to test power generation and battery charging capabilities. In a battery charging test, the charging time for a 40 mAh battery is approximately 1.5 hours for a wind speed of 2.5 m/s. Our experimental results show that the prototype can harvest energy in urban areas with low wind speeds, and convert the wasted wind energy into electricity for city use.

Neglected locked vertical patellar dislocation

PubMed Central

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

2012-01-01

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

Horizontal-axis clothes washer market poised for expansion

DOE Office of Scientific and Technical Information (OSTI.GOV)

George, K.L.

1994-12-31

The availability of energy- and water-efficient horizontal-axis washing machines in the North American market is growing, as US and European manufacturers position for an expected long-term market shift toward horizontal-axis (H-axis) technology. Four of the five major producers of washing machines in the US are developing or considering new H-axis models. New entrants, including US-based Staber Industries and several European manufacturers, are also expected to compete in this market. The intensified interest in H-axis technology is partly driven by speculation that new US energy efficiency standards, to be proposed in 1996 and implemented in 1999, will effectively mandate H-axis machines.more » H-axis washers typically use one-third to two-thirds less energy, water, and detergent than vertical-axis machines. Some models also reduce the energy needed to dry the laundry, since their higher spin speeds extract more water than is typical with vertical-axis designs. H-axis washing machines are the focus of two broadly-based efforts to support coordinated research and incentive programs by electric, gas, and water utilities: The High-Efficiency Laundry Metering/Marketing Analysis (THELMA), and the Consortium for Energy Efficiency (CEE) High-Efficiency Clothes Washer Initiative. These efforts may help to pave the way for new types of marketing partnerships among utilities and other parties that could help to speed adoption of H-axis washers.« less

P-wave indices in patients with pulmonary emphysema: do P-terminal force and interatrial block have confounding effects?

PubMed Central

Chhabra, Lovely; Chaubey, Vinod K; Kothagundla, Chandrasekhar; Bajaj, Rishi; Kaul, Sudesh; Spodick, David H

2013-01-01

Introduction Pulmonary emphysema causes several electrocardiogram changes, and one of the most common and well known is on the frontal P-wave axis. P-axis verticalization (P-axis > 60°) serves as a quasidiagnostic indicator of emphysema. The correlation of P-axis verticalization with the radiological severity of emphysema and severity of chronic obstructive lung function have been previously investigated and well described in the literature. However, the correlation of P-axis verticalization in emphysema with other P-indices like P-terminal force in V1 (Ptf), amplitude of initial positive component of P-waves in V1 (i-PV1), and interatrial block (IAB) have not been well studied. Our current study was undertaken to investigate the effects of emphysema on these P-wave indices in correlation with the verticalization of the P-vector. Materials and methods Unselected, routinely recorded electrocardiograms of 170 hospitalized emphysema patients were studied. Significant Ptf (s-Ptf) was considered ≥40 mm.ms and was divided into two types based on the morphology of P-waves in V1: either a totally negative (−) P wave in V1 or a biphasic (+/−) P wave in V1. Results s-Ptf correlated better with vertical P-vectors than nonvertical P-vectors (P = 0.03). s-Ptf also significantly correlated with IAB (P = 0.001); however, IAB and P-vector verticalization did not appear to have any significant correlation (P = 0.23). There was a very weak correlation between i-PV1 and frontal P-vector (r = 0.15; P = 0.047); however, no significant correlation was found between i-PV1 and P-amplitude in lead III (r = 0.07; P = 0.36). Conclusion We conclude that increased P-tf in emphysema may be due to downward right atrial position caused by right atrial displacement, and thus the common assumption that increased P-tf implies left atrial enlargement should be made with caution in patients with emphysema. Also, the lack of strong correlation between i-PV1 and P-amplitude in lead III or vertical P-vector may suggest the predominant role of downward right atrial distortion rather than right atrial enlargement in causing vertical P-vector in emphysema. PMID:23690680

Spin-stabilized magnetic levitation without vertical axis of rotation

DOEpatents

Romero, Louis [Albuquerque, NM; Christenson, Todd [Albuquerque, NM; Aaronson, Gene [Albuquerque, NM

2009-06-09

The symmetry properties of a magnetic levitation arrangement are exploited to produce spin-stabilized magnetic levitation without aligning the rotational axis of the rotor with the direction of the force of gravity. The rotation of the rotor stabilizes perturbations directed parallel to the rotational axis.

Comparison of current meters used for stream gaging

USGS Publications Warehouse

Fulford, Janice M.; Thibodeaux, Kirk G.; Kaehrle, William R.

1994-01-01

The U.S. Geological Survey (USGS) is field and laboratory testing the performance of several current meters used throughout the world for stream gaging. Meters tested include horizontal-axis current meters from Germany, the United Kingdom, and the People's Republic of China, and vertical-axis and electromagnetic current meters from the United States. Summarized are laboratory test results for meter repeatability, linearity, and response to oblique flow angles and preliminary field testing results. All current meters tested were found to under- and over-register velocities; errors usually increased as the velocity and angle of the flow increased. Repeatability and linearity of all meters tested were good. In the field tests, horizontal-axis meters, except for the two meters from the People's Republic of China, registered higher velocity than did the vertical-axis meters.

Prediction of passenger ride quality in a multifactor environment

NASA Technical Reports Server (NTRS)

Dempsey, T. K.; Leatherwood, J. D.

1976-01-01

A model being developed, permits the understanding and prediction of passenger discomfort in a multifactor environment with particular emphasis upon combined noise and vibration. The model has general applicability to diverse transportation systems and provides a means of developing ride quality design criteria as well as a diagnostic tool for identifying the vibration and/or noise stimuli causing discomfort. Presented are: (1) a review of the basic theoretical and mathematical computations associated with the model, (2) a discussion of methodological and criteria investigations for both the vertical and roll axes of vibration, (3) a description of within-axis masking of discomfort responses for the vertical axis, thereby allowing prediction of the total discomfort due to any random vertical vibration, (4) a discussion of initial data on between-axis masking, and (5) discussion of a study directed towards extension of the vibration model to the more general case of predicting ride quality in the combined noise and vibration environments.

Human otolith-ocular reflexes during off-vertical axis rotation: effect of frequency on tilt-translation ambiguity and motion sickness

NASA Technical Reports Server (NTRS)

Wood, Scott J.; Paloski, W. H. (Principal Investigator)

2002-01-01

The purpose of this study was to examine how the modulation of tilt and translation otolith-ocular responses during constant velocity off-vertical axis rotation varies as a function of stimulus frequency. Eighteen human subjects were rotated in darkness about their longitudinal axis 30 degrees off-vertical at stimulus frequencies between 0.05 and 0.8 Hz. The modulation of torsion decreased while the modulation of horizontal slow phase velocity (SPV) increased with increasing frequency. It is inferred that the ambiguity of otolith afferent information is greatest in the frequency region where tilt (torsion) and translational (horizontal SPV) otolith-ocular responses crossover. It is postulated that the previously demonstrated peak in motion sickness susceptibility during linear accelerations around 0.3 Hz is the result of frequency segregation of ambiguous otolith information being inadequate to distinguish between tilt and translation.

Numerical modeling and preliminary validation of drag-based vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Krysiński, Tomasz; Buliński, Zbigniew; Nowak, Andrzej J.

2015-03-01

The main purpose of this article is to verify and validate the mathematical description of the airflow around a wind turbine with vertical axis of rotation, which could be considered as representative for this type of devices. Mathematical modeling of the airflow around wind turbines in particular those with the vertical axis is a problematic matter due to the complex nature of this highly swirled flow. Moreover, it is turbulent flow accompanied by a rotation of the rotor and the dynamic boundary layer separation. In such conditions, the key aspects of the mathematical model are accurate turbulence description, definition of circular motion as well as accompanying effects like centrifugal force or the Coriolis force and parameters of spatial and temporal discretization. The paper presents the impact of the different simulation parameters on the obtained results of the wind turbine simulation. Analysed models have been validated against experimental data published in the literature.

A study of rotor and platform design trade-offs for large-scale floating vertical axis wind turbines

NASA Astrophysics Data System (ADS)

Griffith, D. Todd; Paquette, Joshua; Barone, Matthew; Goupee, Andrew J.; Fowler, Matthew J.; Bull, Diana; Owens, Brian

2016-09-01

Vertical axis wind turbines are receiving significant attention for offshore siting. In general, offshore wind offers proximity to large populations centers, a vast & more consistent wind resource, and a scale-up opportunity, to name a few beneficial characteristics. On the other hand, offshore wind suffers from high levelized cost of energy (LCOE) and in particular high balance of system (BoS) costs owing to accessibility challenges and limited project experience. To address these challenges associated with offshore wind, Sandia National Laboratories is researching large-scale (MW class) offshore floating vertical axis wind turbines (VAWTs). The motivation for this work is that floating VAWTs are a potential transformative technology solution to reduce offshore wind LCOE in deep-water locations. This paper explores performance and cost trade-offs within the design space for floating VAWTs between the configurations for the rotor and platform.

Exploring point-cloud features from partial body views for gender classification

NASA Astrophysics Data System (ADS)

Fouts, Aaron; McCoppin, Ryan; Rizki, Mateen; Tamburino, Louis; Mendoza-Schrock, Olga

2012-06-01

In this paper we extend a previous exploration of histogram features extracted from 3D point cloud images of human subjects for gender discrimination. Feature extraction used a collection of concentric cylinders to define volumes for counting 3D points. The histogram features are characterized by a rotational axis and a selected set of volumes derived from the concentric cylinders. The point cloud images are drawn from the CAESAR anthropometric database provided by the Air Force Research Laboratory (AFRL) Human Effectiveness Directorate and SAE International. This database contains approximately 4400 high resolution LIDAR whole body scans of carefully posed human subjects. Success from our previous investigation was based on extracting features from full body coverage which required integration of multiple camera images. With the full body coverage, the central vertical body axis and orientation are readily obtainable; however, this is not the case with a one camera view providing less than one half body coverage. Assuming that the subjects are upright, we need to determine or estimate the position of the vertical axis and the orientation of the body about this axis relative to the camera. In past experiments the vertical axis was located through the center of mass of torso points projected on the ground plane and the body orientation derived using principle component analysis. In a natural extension of our previous work to partial body views, the absence of rotational invariance about the cylindrical axis greatly increases the difficulty for gender classification. Even the problem of estimating the axis is no longer simple. We describe some simple feasibility experiments that use partial image histograms. Here, the cylindrical axis is assumed to be known. We also discuss experiments with full body images that explore the sensitivity of classification accuracy relative to displacements of the cylindrical axis. Our initial results provide the basis for further investigation of more complex partial body viewing problems and new methods for estimating the two position coordinates for the axis location and the unknown body orientation angle.

On the stability of motion of several types of heavy symmetric gyroscopes with damping torques

NASA Astrophysics Data System (ADS)

Ge, Z.-M.; Wu, M.-H.

Sufficient conditions for the stability of motion of several gyroscopes are obtained using Liapunov's direct method. The stability of a 'temporarily' sleeping top with damping torque is considered for the cases of the support being fixed, being in vertical harmonic motion, and being in vertical periodic motion. Sufficient conditions are also obtained for the stability of a heavy symmetric gyroscope with damping torque and motor torque for the cases of regular precession, vertical axis permanent rotation with and without the axis of the outer gimbal being inclined, and the gyroscope being in a Newtonian central gravitational field.

Dynamic modulation of ocular orientation during visually guided saccades and smooth-pursuit eye movements

NASA Technical Reports Server (NTRS)

Hess, Bernhard J M.; Angelaki, Dora E.

2003-01-01

Rotational disturbances of the head about an off-vertical yaw axis induce a complex vestibuloocular reflex pattern that reflects the brain's estimate of head angular velocity as well as its estimate of instantaneous head orientation (at a reduced scale) in space coordinates. We show that semicircular canal and otolith inputs modulate torsional and, to a certain extent, also vertical ocular orientation of visually guided saccades and smooth-pursuit eye movements in a similar manner as during off-vertical axis rotations in complete darkness. It is suggested that this graviceptive control of eye orientation facilitates rapid visual spatial orientation during motion.

Device for passive flow control around vertical axis marine turbine

NASA Astrophysics Data System (ADS)

Coşoiu, C. I.; Georgescu, A. M.; Degeratu, M.; Haşegan, L.; Hlevca, D.

2012-11-01

The power supplied by a turbine with the rotor placed in a free stream flow may be increased by augmenting the velocity in the rotor area. The energy of the free flow is dispersed and it may be concentrated by placing a profiled structure around the bare turbine in order to concentrate more energy in the rotor zone. At the Aerodynamic and Wind Engineering Laboratory (LAIV) of the Technical University of Civil Engineering of Bucharest (UTCB) it was developed a concentrating housing to be used for hydro or aeolian horizontal axis wind turbines, in order to increase the available energy in the active section of turbine rotor. The shape of the concentrating housing results by superposing several aero/hydro dynamic effects, the most important being the one generated by the passive flow control devices that were included in the housing structure. Those concentrating housings may be also adapted for hydro or aeolian turbines with vertical axis. The present paper details the numerical research effectuated at the LAIV to determine the performances of a vertical axis marine turbine equipped with such a concentrating device, in order to increase the energy quantity extracted from the main flow. The turbine is a Darrieus type one with three vertical straight blades, symmetric with respect to the axis of rotation, generated using a NACA4518 airfoil. The global performances of the turbine equipped with the concentrating housing were compared to the same characteristics of the bare turbine. In order to validate the numerical approach used in this paper, test cases from the literature resulting from experimental and numerical simulations for similar situations, were used.

Visually induced adaptation in three-dimensional organization of primate vestibuloocular reflex

NASA Technical Reports Server (NTRS)

Angelaki, D. E.; Hess, B. J.

1998-01-01

The adaptive plasticity of the spatial organization of the vestibuloocular reflex (VOR) has been investigated in intact and canal-plugged primates using 2-h exposure to conflicting visual (optokinetic, OKN) and vestibular rotational stimuli about mutually orthogonal axes (generating torsional VOR + vertical OKN, torsional VOR + horizontal OKN, vertical VOR + horizontal OKN, and horizontal VOR + vertical OKN). Adaptation protocols with 0.5-Hz (+/-18 degrees ) head movements about either an earth-vertical or an earth-horizontal axis induced orthogonal response components as high as 40-70% of those required for ideal adaptation. Orthogonal response gains were highest at the adapting frequency with phase leads present at lower and phase lags present at higher frequencies. Furthermore, the time course of adaptation, as well as orthogonal response dynamics were similar and relatively independent of the particular visual/vestibular stimulus combination. Low-frequency (0. 05 Hz, vestibular stimulus: +/-60 degrees ; optokinetic stimulus: +/-180 degrees ) adaptation protocols with head movements about an earth-vertical axis induced smaller orthogonal response components that did not exceed 20-40% of the head velocity stimulus (i.e., approximately 10% of that required for ideal adaptation). At the same frequency, adaptation with head movements about an earth-horizontal axis generated large orthogonal responses that reached values as high as 100-120% of head velocity after 2 h of adaptation (i.e., approximately 40% of ideal adaptation gains). The particular spatial and temporal response characteristics after low-frequency, earth-horizontal axis adaptation in both intact and canal-plugged animals strongly suggests that the orienting (and perhaps translational) but not inertial (velocity storage) components of the primate otolith-ocular system exhibit spatial adaptability. Due to the particular nested arrangement of the visual and vestibular stimuli, the optic flow pattern exhibited a significant component about the third spatial axis (i.e., orthogonal to the axes of rotation of the head and visual surround) at twice the oscillation frequency. Accordingly, the adapted VOR was characterized consistently by a third response component (orthogonal to both the axes of head and optokinetic drum rotation) at twice the oscillation frequency after earth-horizontal but not after earth-vertical axis 0.05-Hz adaptation. This suggests that the otolith-ocular (but not the semicircular canal-ocular) system can adaptively change its spatial organization at frequencies different from those of the head movement.

Measurement of Posterior Corneal Astigmatism by the IOLMaster 700.

PubMed

LaHood, Benjamin R; Goggin, Michael

2018-05-01

To provide the first description of posterior corneal astigmatism as measured by the IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany) and assess how its characteristics compare to previous measurements from other devices. A total of 1,098 routine IOLMaster 700 biometric measurements were analyzed to provide magnitudes and orientation of steep and flat axes of anterior and posterior corneal astigmatism. Subgroup analysis was conducted to assess correlation of posterior corneal astigmatism characteristics to anterior corneal astigmatism and describe the distribution of posterior corneal astigmatism with age. Mean posterior corneal astigmatism was 0.24 ± 0.15 diopters (D). The steep axis of posterior corneal astigmatism was vertically oriented in 73.32% of measurements. Correlation between the magnitude of anterior and posterior corneal astigmatism was greatest when the steep axis of the anterior corneal astigmatism was oriented vertically (r = 0.68, P < .0001). Vertical orientation of the steep axis of anterior corneal astigmatism became less common as age increased, whereas for posterior corneal astigmatism it remained by far the most common orientation. This first description of posterior corneal astigmatism measurement by the IOLMaster 700 found the average magnitude of posterior corneal astigmatism and proportion of vertical orientation of steep axis was lower than previous estimates. The IOLMaster 700 appears capable of providing enhanced biometric measurement for individualized surgical planning. [J Refract Surg. 2018;34(5):331-336.]. Copyright 2018, SLACK Incorporated.

Modeling of Geometric Error in Linear Guide Way to Improved the vertical three-axis CNC Milling machine’s accuracy

NASA Astrophysics Data System (ADS)

Kwintarini, Widiyanti; Wibowo, Agung; Arthaya, Bagus M.; Yuwana Martawirya, Yatna

2018-03-01

The purpose of this study was to improve the accuracy of three-axis CNC Milling Vertical engines with a general approach by using mathematical modeling methods of machine tool geometric errors. The inaccuracy of CNC machines can be caused by geometric errors that are an important factor during the manufacturing process and during the assembly phase, and are factors for being able to build machines with high-accuracy. To improve the accuracy of the three-axis vertical milling machine, by knowing geometric errors and identifying the error position parameters in the machine tool by arranging the mathematical modeling. The geometric error in the machine tool consists of twenty-one error parameters consisting of nine linear error parameters, nine angle error parameters and three perpendicular error parameters. The mathematical modeling approach of geometric error with the calculated alignment error and angle error in the supporting components of the machine motion is linear guide way and linear motion. The purpose of using this mathematical modeling approach is the identification of geometric errors that can be helpful as reference during the design, assembly and maintenance stages to improve the accuracy of CNC machines. Mathematically modeling geometric errors in CNC machine tools can illustrate the relationship between alignment error, position and angle on a linear guide way of three-axis vertical milling machines.

Calculating Radiation Dose for Biological Tissue

NASA Image and Video Library

2013-05-30

This graph based on data from the RAD instrument onboard NASA Mars Science Laboratory spacecraft shows the flux of energetic particles vertical axis as a function of the estimated energy deposited in water horizontal axis.

Optimal electrocardiographic limb lead set for rapid emphysema screening

PubMed Central

Bajaj, Rishi; Chhabra, Lovely; Basheer, Zainab; Spodick, David H

2013-01-01

Background Pulmonary emphysema of any etiology has been shown to be strongly and quasidiagnostically associated with a vertical frontal P wave axis. A vertical P wave axis (>60 degrees) during sinus rhythm can be easily determined by a P wave in lead III greater than the P wave in lead I (bipolar lead set) or a dominantly negative P wave in aVL (unipolar lead set). The purpose of this investigation was to determine which set of limb leads may be better for identifying the vertical P vector of emphysema in adults. Methods Unselected consecutive electrocardiograms from 100 patients with a diagnosis of emphysema were analyzed to determine the P wave axis. Patients aged younger than 45 years, those not in sinus rhythm, and those with poor quality tracings were excluded. The electrocardiographic data were divided into three categories depending on the frontal P wave axis, ie, >60 degrees, 60 degrees, or <60 degrees, by each criterion (P amplitude lead III > lead I and a negative P wave in aVL). Results Sixty-six percent of patients had a P wave axis > 60 degrees based on aVL, and 88% of patients had a P wave axis > 60 degrees based on the P wave in lead III being greater than in lead I. Conclusion A P wave in lead III greater than that in lead I is a more sensitive marker than a negative P wave in aVL for diagnosing emphysema and is recommended for rapid routine screening. PMID:23378754

Multi-photon vertical cross-sectional imaging with a dynamically-balanced thin-film PZT z-axis microactuator.

PubMed

Choi, Jongsoo; Duan, Xiyu; Li, Haijun; Wang, Thomas D; Oldham, Kenn R

2017-10-01

Use of a thin-film piezoelectric microactuator for axial scanning during multi-photon vertical cross-sectional imaging is described. The actuator uses thin-film lead-zirconate-titanate (PZT) to generate upward displacement of a central mirror platform, micro-machined from a silicon-on-insulator (SOI) wafer to dimensions compatible with endoscopic imaging instruments. Device modeling in this paper focuses on existence of frequencies near device resonance producing vertical motion with minimal off-axis tilt even in the presence of multiple vibration modes and non-uniformity in fabrication outcomes. Operation near rear resonance permits large stroke lengths at low voltages relative to other vertical microactuators. Highly uniform vertical motion of the mirror platform is a key requirement for vertical cross-sectional imaging in the remote scan architecture being used for multi-photon instrument prototyping. The stage is installed in a benchtop testbed in combination with an electrostatic mirror that performs in-plane scanning. Vertical sectional images are acquired from 15 μm diameter beads and excised mouse colon tissue.

In search of the pitching momentum that enables some lizards to sustain bipedal running at constant speeds

PubMed Central

Van Wassenbergh, Sam; Aerts, Peter

2013-01-01

The forelimbs of lizards are often lifted from the ground when they start sprinting. Previous research pointed out that this is a consequence of the propulsive forces from the hindlimbs. However, despite forward acceleration being hypothesized as necessary to lift the head, trunk and forelimbs, some species of agamids, teiids and basilisks sustain running in a bipedal posture at a constant speed for a relatively long time. Biomechanical modelling of steady bipedal running in the agamid Ctenophorus cristatus now shows that a combination of three mechanisms must be present to generate the angular impulse needed to cancel or oppose the effect of gravity. First, the trunk must be lifted significantly to displace the centre of mass more towards the hip joint. Second, the nose-up pitching moment resulting from aerodynamic forces exerted at the lizard's surface must be taken into account. Third, the vertical ground-reaction forces at the hindlimb must show a certain degree of temporal asymmetry with higher forces closer to the instant of initial foot contact. Such asymmetrical vertical ground-reaction force profiles, which differ from the classical spring-mass model of bipedal running, seem inherent to the windmilling, splayed-legged running style of lizards. PMID:23658116

Gravitomagnetic acceleration from black hole accretion disks

NASA Astrophysics Data System (ADS)

Poirier, J.; Mathews, G. J.

2016-05-01

We demonstrate how the motion of the neutral masses in an accretion disk orbiting a black hole creates a general-relativistic magnetic-like (gravitomagnetic) field that vertically accelerates neutral particles near an accretion disk upward and then inward toward the axis of the accretion disk. Even though this gravitomagnetic field is not the only mechanism contributing to the production of jets, it presents a novel means to identify one general relativistic effect from a much more complicated problem. In addition, as the accelerated material above or below the accretion disk nears the axis with a nearly vertical direction, a frame-dragging effect twists the trajectories around the axis thus contributing to the collimation of the jet.

Turbulent premixed combustion in V-shaped flames: Characteristics of flame front

NASA Astrophysics Data System (ADS)

Kheirkhah, S.; Gülder, Ö. L.

2013-05-01

Flame front characteristics of turbulent premixed V-shaped flames were investigated experimentally using the Mie scattering and the particle image velocimetry techniques. The experiments were performed at mean streamwise exit velocities of 4.0, 6.2, and 8.6 m/s, along with fuel-air equivalence ratios of 0.7, 0.8, and 0.9. Effects of vertical distance from the flame-holder, mean streamwise exit velocity, and fuel-air equivalence ratio on statistics of the distance between the flame front and the vertical axis, flame brush thickness, flame front curvature, and angle between tangent to the flame front and the horizontal axis were studied. The results show that increasing the vertical distance from the flame-holder and the fuel-air equivalence ratio increase the mean and root-mean-square (RMS) of the distance between the flame front and the vertical axis; however, increasing the mean streamwise exit velocity decreases these statistics. Spectral analysis of the fluctuations of the flame front position depicts that the normalized and averaged power-spectrum-densities collapse and show a power-law relation with the normalized wave number. The flame brush thickness is linearly correlated with RMS of the distance between the flame front and the vertical axis. Analysis of the curvature of the flame front data shows that the mean curvature is independent of the experimental conditions tested and equals to zero. Values of the inverse of the RMS of flame front curvature are similar to those of the integral length scale, suggesting that the large eddies in the flow make a significant contribution in wrinkling of the flame front. Spectral analyses of the flame front curvature as well as the angle between tangent to the flame front and the horizontal axis show that the power-spectrum-densities feature a peak. Value of the inverse of the wave number pertaining to the peak is larger than that of the integral length scale.

FORGE Milford Triaxial Test Data and Summary from EGI labs

DOE Data Explorer

Joe Moore

2016-03-01

Six samples were evaluated in unconfined and triaxial compression, their data are included in separate excel spreadsheets, and summarized in the word document. Three samples were plugged along the axis of the core (presumed to be nominally vertical) and three samples were plugged perpendicular to the axis of the core. A designation of "V"indicates vertical or the long axis of the plugged sample is aligned with the axis of the core. Similarly, "H" indicates a sample that is nominally horizontal and cut orthogonal to the axis of the core. Stress-strain curves were made before and after the testing, and are included in the word doc.. The confining pressure for this test was 2800 psi. A series of tests are being carried out on to define a failure envelope, to provide representative hydraulic fracture design parameters and for future geomechanical assessments. The samples are from well 52-21, which reaches a maximum depth of 3581 ft +/- 2 ft into a gneiss complex.

The vibration discomfort of standing people: evaluation of multi-axis vibration.

PubMed

Thuong, Olivier; Griffin, Michael J

2015-01-01

Few studies have investigated discomfort caused by multi-axis vibration and none has explored methods of predicting the discomfort of standing people from simultaneous fore-and-aft, lateral and vertical vibration of a floor. Using the method of magnitude estimation, 16 subjects estimated their discomfort caused by dual-axis and tri-axial motions (octave-bands centred on either 1 or 4 Hz with various magnitudes in the fore-and-aft, lateral and vertical directions) and the discomfort caused by single-axis motions. The method of predicting discomfort assumed in current standards (square-root of the sums of squares of the three components weighted according to their individual contributions to discomfort) provided reasonable predictions of the discomfort caused by multi-axis vibration. Improved predictions can be obtained for specific stimuli, but no single simple method will provide accurate predictions for all stimuli because the rate of growth of discomfort with increasing magnitude of vibration depends on the frequency and direction of vibration.

Water Landing Characteristics of a Reentry Capsule

NASA Technical Reports Server (NTRS)

1958-01-01

Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions.

Water-Landing Characteristics of a Reentry Capsule

NASA Technical Reports Server (NTRS)

McGehee, John R.; Hathaway, Melvin E.; Vaughan, Victor L., Jr.

1959-01-01

Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions.

Cross-axis adaptation of torsional components in the yaw-axis vestibulo-ocular reflex

NASA Technical Reports Server (NTRS)

Trillenberg, P.; Shelhamer, M.; Roberts, D. C.; Zee, D. S.

2003-01-01

The three pairs of semicircular canals within the labyrinth are not perfectly aligned with the pulling directions of the six extraocular muscles. Therefore, for a given head movement, the vestibulo-ocular reflex (VOR) depends upon central neural mechanisms that couple the canals to the muscles with the appropriate functional gains in order to generate a response that rotates the eye the correct amount and around the correct axis. A consequence of these neural connections is a cross-axis adaptive capability, which can be stimulated experimentally when head rotation is around one axis and visual motion about another. From this visual-vestibular conflict the brain infers that the slow-phase eye movement is rotating around the wrong axis. We explored the capability of human cross-axis adaptation, using a short-term training paradigm, to determine if torsional eye movements could be elicited by yaw (horizontal) head rotation (where torsion is normally inappropriate). We applied yaw sinusoidal head rotation (+/-10 degrees, 0.33 Hz) and measured eye movement responses in the dark, and before and after adaptation. The adaptation paradigm lasted 45-60 min, and consisted of the identical head motion, coupled with a moving visual scene that required one of several types of eye movements: (1) torsion alone (-Roll); (2) horizontal/torsional, head right/CW torsion (Yaw-Roll); (3) horizontal/torsional, head right/CCW torsion (Yaw+Roll); (4) horizontal, vertical, torsional combined (Yaw+Pitch-Roll); and (5) horizontal and vertical together (Yaw+Pitch). The largest and most significant changes in torsional amplitude occurred in the Yaw-Roll and Yaw+Roll conditions. We conclude that short-term, cross-axis adaptation of torsion is possible but constrained by the complexity of the adaptation task: smaller torsional components are produced if more than one cross-coupling component is required. In contrast, vertical cross-axis components can be easily trained to occur with yaw head movements.

Vestibulo-ocular reflex of the squirrel monkey during eccentric rotation with centripetal acceleration along the naso-occipital axis

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Paloski, W. H. (Principal Investigator)

1996-01-01

The vestibulo-ocular reflexes (VOR) are determined not only by angular acceleration, but also by the presence of gravity and linear acceleration. This phenomenon was studied by measuring three-dimensional nystagmic eye movements, with implanted search coils, in four male squirrel monkeys. Monkeys were rotated in the dark at 200 degrees/s, centrally or 79 cm off-axis, with the axis of rotation always aligned with gravity and the spinal axis of the upright monkeys. The monkey's position relative to the centripetal acceleration (facing center or back to center) had a dramatic influence on the VOR. These studies show that a torsional response was always elicited that acted to shift the axis of eye rotation toward alignment with gravito-inertial force. On the other hand, a slow phase downward vertical response usually existed, which shifted the axis of eye rotation away from the gravito-inertial force. These findings were consistent across all monkeys. In another set of tests, the same monkeys were rapidly tilted about their interaural (pitch) axis. Tilt orientations of 45 degrees and 90 degrees were maintained for 1 min. Other than a compensatory angular VOR during the rotation, no consistent eye velocity response was ever observed during or following the tilt. The absence of any response following tilt proves that the observed torsional and vertical responses were not a positional nystagmus. Model simulations qualitatively predict all components of these eccentric rotation and tilt responses. These simulations support the conclusion that the VOR during eccentric rotation may consist of two components: a linear VOR and a rotational VOR. The model predicts a slow phase downward, vertical, linear VOR during eccentric rotation even though there was never a change in the force aligned with monkey's spinal (Z) axis. The model also predicts the torsional components of the response that shift the rotation axis of the angular VOR toward alignment with gravito-inertial force.

Vestibulo-ocular reflex of the squirrel monkey during eccentric rotation with centripetal acceleration along the naso-occipital axis.

PubMed

Merfeld, D M

1996-01-01

The vestibulo-ocular reflexes (VOR) are determined not only by angular acceleration, but also by the presence of gravity and linear acceleration. This phenomenon was studied by measuring three-dimensional nystagmic eye movements, with implanted search coils, in four male squirrel monkeys. Monkeys were rotated in the dark at 200 degrees/s, centrally or 79 cm off-axis, with the axis of rotation always aligned with gravity and the spinal axis of the upright monkeys. The monkey's position relative to the centripetal acceleration (facing center or back to center) had a dramatic influence on the VOR. These studies show that a torsional response was always elicited that acted to shift the axis of eye rotation toward alignment with gravito-inertial force. On the other hand, a slow phase downward vertical response usually existed, which shifted the axis of eye rotation away from the gravito-inertial force. These findings were consistent across all monkeys. In another set of tests, the same monkeys were rapidly tilted about their interaural (pitch) axis. Tilt orientations of 45 degrees and 90 degrees were maintained for 1 min. Other than a compensatory angular VOR during the rotation, no consistent eye velocity response was ever observed during or following the tilt. The absence of any response following tilt proves that the observed torsional and vertical responses were not a positional nystagmus. Model simulations qualitatively predict all components of these eccentric rotation and tilt responses. These simulations support the conclusion that the VOR during eccentric rotation may consist of two components: a linear VOR and a rotational VOR. The model predicts a slow phase downward, vertical, linear VOR during eccentric rotation even though there was never a change in the force aligned with monkey's spinal (Z) axis. The model also predicts the torsional components of the response that shift the rotation axis of the angular VOR toward alignment with gravito-inertial force.

Electric power from vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Touryan, K. J.; Strickland, J. H.; Berg, D. E.

1987-12-01

Significant advancements have occurred in vertical axis wind turbine (VAWT) technology for electrical power generation over the last decade; in particular, well-proven aerodynamic and structural analysis codes have been developed for Darrieus-principle wind turbines. Machines of this type have been built by at least three companies, and about 550 units of various designs are currently in service in California wind farms. Attention is presently given to the aerodynamic characteristics, structural dynamics, systems engineering, and energy market-penetration aspects of VAWTs.

M-X Environmental Technical Report. Environmental Characteristics of Alternative Designated Deployment Areas, Power and Energy.

DTIC Science & Technology

1980-12-22

Vertical Axis Turbine (3.4.2) A vertical axis ( Darrieus ) turbine has the following advantages over a horizontal turbine : I. Accepts wind from all...would be too large, while wind and solar could only achieve capacity factors of 40 to 50 percent. Alcohol fue’s in gas turbines would be too expensive...or biomass base load system. Wind would not be a good choice to supply such a small toad cencer, especially in Nevada/Utah, since the turbine would

Unsteady Gas Dynamics Problems Related to Flight Vehicles

DTIC Science & Technology

1979-05-01

vertical-axis wind turbines typified by the Darrieus machine (see Cha’. !. Ref. R9 and R10). When cUL.figured in the zero-bending- moment Tropeq.-!n...Performance Data for the Darrieus Wind Turbine with NASA 0012 Blades," Sandia Labs Energy Report, SAND 76-0130, May 1976. R11. Steele, C.R., "Application of...aspect!ratio wings proved often to be unfavorable. Improved steady and unsteady theories were published for the loading of vertical-axis wind turbines

Design and fabrication of a low-cost Darrieus vertical-axis wind-turbine system, volume 2

NASA Astrophysics Data System (ADS)

1983-03-01

The fabrication, installation, and checkout of 100-kW 17 meter vertical axis wind turbines is described. Turbines are Darrieus-type VAWIs with rotors 17 meters and 25.15 meters in height. They can produce 100 kW of electric power at a cost of energy as low as 3 cents per kWh, in an 18-mph wind regime using 12% annualized costs. Four turbines were produced; three are installed and are operable. Contract results are documented.

Estimation of power in low velocity vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Sampath, S. S.; Shetty, Sawan; Chithirai Pon Selvan, M.

2015-06-01

The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical components of the entire setup are built to obtain maximum rotation per minute. The mechanical energy is converted into the electrical energy by coupling coaxially between the shaft and the generator. This setup produces sufficient power for consumption of household purposes which is economic and easily available.

Model surgery with a passive robot arm for orthognathic surgery planning.

PubMed

Theodossy, Tamer; Bamber, Mohammad Anwar

2003-11-01

The aims of the study were to assess the degree of accuracy of model surgery performed manually using the Eastman technique and to compare it with model surgery performed with the aid of a robot arm. Twenty-one patients undergoing orthognathic surgery gave consent for this study. They were divided into 2 groups based on the model surgery technique used. Group A (52%) had model surgery performed manually, whereas group B (48%) had their model surgery performed using the robot arm. Patients' maxillary casts were measured before and after model surgery, and results were compared with those for the original treatment plan in horizontal (x-axis), vertical (y-axis), and transverse (z-axis) planes. Statistical analysis using Mann-Whitney U test for x- and y-axis and independent sample t test for z-axis have shown significant differences between both groups in x-axis (P =.024) and y-axis (P =.01) but not in z-axis (P =.776). Model surgery performed with the aid of a robot arm is significantly more accurate in anteroposterior and vertical planes than is manual model surgery. Robot arm has an important role to play in orthognathic surgery planning and in determining the biometrics of orthognathic surgical change at the model surgery stage.

Passive magnetic bearing configurations

DOEpatents

Post, Richard F [Walnut Creek, CA

2011-01-25

A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

Design analysis of vertical wind turbine with airfoil variation

NASA Astrophysics Data System (ADS)

Maulana, Muhammad Ilham; Qaedy, T. Masykur Al; Nawawi, Muhammad

2016-03-01

With an ever increasing electrical energy crisis occurring in the Banda Aceh City, it will be important to investigate alternative methods of generating power in ways different than fossil fuels. In fact, one of the biggest sources of energy in Aceh is wind energy. It can be harnessed not only by big corporations but also by individuals using Vertical Axis Wind Turbines (VAWT). This paper presents a three-dimensional CFD analysis of the influence of airfoil design on performance of a Darrieus-type vertical-axis wind turbine (VAWT). The main objective of this paper is to develop an airfoil design for NACA 63-series vertical axis wind turbine, for average wind velocity 2,5 m/s. To utilize both lift and drag force, some of designs of airfoil are analyzed using a commercial computational fluid dynamics solver such us Fluent. Simulation is performed for this airfoil at different angles of attach rearranging from -12°, -8°, -4°, 0°, 4°, 8°, and 12°. The analysis showed that the significant enhancement in value of lift coefficient for airfoil NACA 63-series is occurred for NACA 63-412.

Modeling human vestibular responses during eccentric rotation and off vertical axis rotation

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Paloski, W. H. (Principal Investigator)

1995-01-01

A mathematical model has been developed to help explain human multi-sensory interactions. The most important constituent of the model is the hypothesis that the nervous system incorporates knowledge of sensory dynamics into an "internal model" of these dynamics. This internal model allows the nervous system to integrate the sensory information from many different sensors into a coherent estimate of self-motion. The essence of the model is unchanged from a previously published model of monkey eye movement responses; only a few variables have been adjusted to yield the prediction of human responses. During eccentric rotation, the model predicts that the axis of eye rotation shifts slightly toward alignment with gravito-inertial force. The model also predicts that the time course of the perception of tilt following the acceleration phase of eccentric rotation is much slower than that during deceleration. During off vertical axis rotation (OVAR) the model predicts a small horizontal bias along with small horizontal, vertical, and torsional oscillations. Following OVAR stimulation, when stopped right- or left-side down, a small vertical component is predicted that decays with the horizontal post-rotatory response. All of the predictions are consistent with measurements of human responses.

Curiosity ChemCam Analyzes Rocks, Soils and Dust

NASA Image and Video Library

2013-04-08

This diagram shows how materials analyzed by the ChemCam instrument on NASA Curiosity Mars rover during the first 100 Martian days of the mission differed with regard to hydrogen content horizontal axis and alkali vertical axis.

Effect of the number of blades and solidity on the performance of a vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Delafin, PL; Nishino, T.; Wang, L.; Kolios, A.

2016-09-01

Two, three and four bladed ϕ-shape Vertical Axis Wind Turbines are simulated using a free-wake vortex model. Two versions of the three and four bladed turbines are considered, one having the same chord length as the two-bladed turbine and the other having the same solidity as the two-bladed turbine. Results of the two-bladed turbine are validated against published experimental data of power coefficient and instantaneous torque. The effect of solidity on the power coefficient is presented and the instantaneous torque, thrust and lateral force of the two-, three- and four-bladed turbines are compared for the same solidity. It is found that increasing the number of blades from two to three significantly reduces the torque, thrust and lateral force ripples. Adding a fourth blade further reduces the ripples except for the torque at low tip speed ratio. This work aims to help choosing the number of blades during the design phase of a vertical axis wind turbine.

Fabric and texture at Siple Dome, Antarctica

USGS Publications Warehouse

Diprinzio, C.L.; Wilen, Lawrence A.; Alley, R.B.; Fitzpatrick, J.J.; Spencer, M.K.; Gow, A.J.

2005-01-01

Preferred c-axis orientations are present in the firn at Siple Dome, West Antarctica, and recrystallization begins as shallow as 200 m depth in ice below -20??C, based on digital analysis of c-axis fabrics, grain-sizes and other characteristics of 52 vertical thin sections prepared in the field from the kilometer-long Siple Dome ice core. The shallowest section analyzed, from 22 m, shows clustering of c axes toward the vertical. By 200 m depth, girdle fabric and other features of recrystallized ice are evident in layers (or regions), separated by layers (regions) of typically finer-grained ice lacking evidence of recrystallization. Ice from about 700-780 m depth, which was deposited during the last ice age, is especially fine-grained, with strongly vertical c axes, but deeper ice shows much larger crystals and strong evidence of recrystallization. Azimuthal asymmetry of some c-axis fabrics, trends in grain-size, and other indicators reveal additional information on processes and history of ice flow at Siple Dome.

Optimization of blade motion of vertical axis turbine

NASA Astrophysics Data System (ADS)

Ma, Yong; Zhang, Liang; Zhang, Zhi-yang; Han, Duan-feng

2016-04-01

In this paper, a method is proposed to improve the energy efficiency of the vertical axis turbine. First of all, a single disk multiple stream-tube model is used to calculate individual fitness. Genetic algorithm is adopted to optimize blade pitch motion of vertical axis turbine with the maximum energy efficiency being selected as the optimization objective. Then, a particular data processing method is proposed, fitting the result data into a cosine-like curve. After that, a general formula calculating the blade motion is developed. Finally, CFD simulation is used to validate the blade pitch motion formula. The results show that the turbine's energy efficiency becomes higher after the optimization of blade pitch motion; compared with the fixed pitch turbine, the efficiency of variable-pitch turbine is significantly improved by the active blade pitch control; the energy efficiency declines gradually with the growth of speed ratio; besides, compactness has lager effect on the blade motion while the number of blades has little effect on it.

Salt structures and vertical axis rotations; a case study in the Barbastro-Balaguer anticline, Southern Pyrenees.

NASA Astrophysics Data System (ADS)

Pueyo, Emilio L.; Oliván, Carlota; Soto, Ruth; Rodríguez-Pintó, Adriana; Santolaria, Pablo; Luzón, Aránzazu; Casas, Antonio M.; Ayala, Conxi

2017-04-01

Vertical axis rotations are common in all deformation settings. At larger scales, for example in fold and thrust belts, they are usually related to differential shortening along strike and this may be caused by a number of reasons (interplay of plate boundaries, sedimentary wedges, detachment level distribution, etc.). At smaller scales, local stress fields, interference of non-coaxial deformation phases, development of non-cylindrical structures, etc. may play an important role to accommodate significant magnitudes of rotation. Apart from their implication in the truly 4D understanding of geological structures, the occurrence of vertical axis rotation usually precludes the application of most 3D restoration techniques and thus, increases the uncertainty in any 3D reconstruction. Salt structures may form in different geological settings, but focusing on compressive regimes, very little is known about the relation between their geometry and kinematics and their ability to accommodate vertical axis rotations (i.e. local or regional lateral gradients of shortening). The Barbastro-Balaguer anticline (BBA) is the southernmost structure of the Central Pyrenees. It is a large detachment fold spreading more than 150 km along the front. In contrast to most frontal Pyrenean structures, the BBA is detached in Priabonian evaporites and was folded during Oligocene times as witnessed by well exposed growth strata. Along strike changes in the fold axis trend may reach 50°, an overall the anticline displays a convex shape towards the foreland (south). A residual Bouguer anomaly map based on a densely sampled gravimetric surveying (10.000 stations) has helped delineating a heterogeneous distribution of the Eocene detachment level in the subsurface. In this contribution we explore the interplay between vertical axis rotations, detachment level distribution and the fold geometry (structural trend and style based on hundreds of data). Seventy paleomagnetic sites evenly and densely distributed along the structure have been analyzed for this purpose. About 600 standard specimens have been thermally demagnetized in the Paleomagnetic Laboratory of the Burgos University (ASC TD48DC thermal demagnetizer and 2G superconducting magnetometer). Data processing has been carried out with the VPD program, applying standard PCA and virtual direction analyses. The ChRM directions passes the fold test and display two polarities, pointing to the primary character of the magnetization (key factor for the 3D restoration). This large dataset allows us to draw a robust network of rotation magnitudes along strike the western sector of the BBA that are key to understand its kinematics together to the aforementioned factors. We also pretend to use this network of vertical axis rotations to restore in 3D this salt structure.

Temporal dynamics of ocular position dependence of the initial human vestibulo-ocular reflex.

PubMed

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

2006-04-01

While an ideal vestibulo-ocular reflex (VOR) generates ocular rotations compensatory for head motion, during visually guided movements, Listing's Law (LL) constrains the eye to rotational axes lying in Listing's Plane (LP). The present study was conducted to explore the recent proposal that the VOR's rotational axis is not collinear with the head's, but rather follows a time-dependent strategy intermediate between LL and an ideal VOR. Binocular LPs were defined during visual fixation in eight normal humans. The VOR was evoked by a highly repeatable transient whole-body yaw rotation in darkness at a peak acceleration of 2800 deg/s2. Immediately before rotation, subjects regarded targets 15 or 500 cm distant located at eye level, 20 degrees up, or 20 degrees down. Eye and head responses were compared with LL predictions in the position and velocity domains. LP orientation varied both among subjects and between individual subject's eyes, and rotated temporally with convergence by 5 +/- 5 degrees (+/-SEM). In the position domain, the eye compensated for head displacement even when the head rotated out of LP. Even within the first 20 ms from onset of head rotation, the ocular velocity axis tilted relative to the head axis by 30% +/- 8% of vertical gaze position. Saccades increased this tilt. Regardless of vertical gaze position, the ocular rotation axis tilted backward 4 degrees farther in abduction than in adduction. There was also a binocular vertical eye velocity transient and lateral tilt of the ocular axis. These disconjugate, short-latency axis perturbations appear intrinsic to the VOR and may have neural or mechanical origins.

Contour symmetry detection: the influence of axis orientation and number of objects.

PubMed

Friedenberg, J; Bertamini, M

2000-09-01

Participants discriminated symmetrical from random contours connected by straight lines to form part of one- or two-objects. In experiment one, symmetrical contours were translated or reflected and presented at vertical, horizontal, and oblique axis orientations with orientation constant within blocks. Translated two-object contours were detected more easily than one, replicating a "lock-and-key" effect obtained previously for vertical orientations only [M. Bertamini, J.D. Friedenberg, M. Kubovy, Acta Psychologica, 95 (1997) 119-140]. A second experiment extended these results to a wider variety of axis orientations under mixed block conditions. The pattern of performance for translation and reflection at different orientations corresponded in both experiments, suggesting that orientation is processed similarly in the detection of these symmetries.

Rotary moving bed for CO.sub.2 separation and use of same

DOEpatents

Elliott, Jeannine Elizabeth; Copeland, Robert James; McCall, Patrick P.

2017-01-10

A rotary moving bed and process for separating a carbon dioxide from a gas stream is disclosed. The rotary moving bed can have a rotational assembly rotating on a vertical axis, and a plurality of sorbent cells positioned horizontally to the axis of rotation that fills a vertical space in the moving bed, where the sorbent cells adsorb the carbon dioxide by concentration swing adsorption and adsorptive displacement. The sorbent can be regenerated and the carbon dioxide recaptured by desorbing the carbon dioxide from the sorbent using concentration swing adsorption and desorptive displacement with steam. The gas flows in the system flow in a direction horizontal to the axis of rotation and in a direction opposite the rotational movement of the sorbent cells.

Review of gravitomagnetic acceleration from accretion disks

NASA Astrophysics Data System (ADS)

Poirier, J.; Mathews, G. J.

2015-11-01

We review the development of the equations of gravitoelectromagnetism and summarize how the motion of the neutral masses in an accretion disk orbiting a black hole creates a general-relativistic magnetic-like (gravitomagnetic) field that vertically accelerates neutral particles near the accretion disk upward and then inward toward the axis of the accretion disk. Even though this gravitomagnetic field is not the only mechanism to produce collimated jets, it is a novel means to identify one general relativistic effect from a much more complicated problem. In addition, as the accelerated material above or below the accretion disk nears the axis with a nearly vertical direction, a frame-dragging effect twists the trajectories around the axis thus contributing to the collimation of the jet.

Design and analysis of large-core single-mode windmill single crystal sapphire optical fiber

DOE PAGES

Cheng, Yujie; Hill, Cary; Liu, Bo; ...

2016-06-01

We present a large-core single-mode “windmill” single crystal sapphire optical fiber (SCSF) design, which exhibits single-mode operation by stripping off the higher-order modes (HOMs) while maintaining the fundamental mode. The “windmill” SCSF design was analyzed using the finite element analysis method, in which all the HOMs are leaky. The numerical simulation results show single-mode operation in the spectral range from 0.4 to 2 μm in the windmill SCSF, with an effective core diameter as large as 14 μm. Such fiber is expected to improve the performance of many of the current sapphire fiber optic sensor structures.

Proceedings of the vertical axis wind turbine (VAWT) design technology seminar for industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, S.F. Jr.

1980-08-01

The objective of the Vertical Axis Wind Turbine (VAWT) Program at Sandia National Laboratories is to develop technology that results in economical, industry-produced, and commercially marketable wind energy systems. The purpose of the VAWT Design Technology Seminar or Industry was to provide for the exchange of the current state-of-the-art and predictions for future VAWT technology. Emphasis was placed on technology transfer on Sandia's technical developments and on defining the available analytic and design tools. Separate abstracts are included for presented papers.

Dynamic aeroelastic stability of vertical-axis wind turbines under constant wind velocity

NASA Astrophysics Data System (ADS)

Nitzsche, Fred

1994-05-01

The flutter problem associated with the blades of a class of vertical-axis wind turbines called Darrieus is studied in detail. The spinning blade is supposed to be initially curved in a particular shape characterized by a state of pure tension at the blade cross section. From this equilibrium position a three-dimensional linear perturbation pattern is superimposed to determine the dynamic aeroelastic stability of the blade in the presence of free wind speed by means of the Floquet-Lyapunov theory for periodic systems.

Experimental characterization of vertical-axis wind turbine noise.

PubMed

Pearson, C E; Graham, W R

2015-01-01

Vertical-axis wind turbines are wind-energy generators suitable for use in urban environments. Their associated noise thus needs to be characterized and understood. As a first step, this work investigates the relative importance of harmonic and broadband contributions via model-scale wind-tunnel experiments. Cross-spectra from a pair of flush-mounted wall microphones exhibit both components, but further analysis shows that the broadband dominates at frequencies corresponding to the audible range in full-scale operation. This observation has detrimental implications for noise-prediction reliability and hence also for acoustic design optimization.

Kinematics of a vertical axis wind turbine with a variable pitch angle

NASA Astrophysics Data System (ADS)

Jakubowski, Mateusz; Starosta, Roman; Fritzkowski, Pawel

2018-01-01

A computational model for the kinematics of a vertical axis wind turbine (VAWT) is presented. A H-type rotor turbine with a controlled pitch angle is considered. The aim of this solution is to improve the VAWT productivity. The discussed method is related to a narrow computational branch based on the Blade Element Momentum theory (BEM theory). The paper can be regarded as a theoretical basis and an introduction to further studies with the application of BEM. The obtained torque values show the main advantage of using the variable pitch angle.

The role of electrocardiography in evaluation of severity of chronic obstructive pulmonary disease in daily clinical practice.

PubMed

Aktürk, Faruk; Bıyık, İsmail; Kocaş, Cüneyt; Ertürk, Mehmet; Yalçın, Ahmet Arif; Savaş, Ayfer Utku; Kuzer, Firuzan Pınar; Uzun, Fatih; Yıldırım, Aydın; Uslu, Nevzat; Çuhadaroğlu, Çağlar

2013-01-01

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of chronic morbidity and mortality. Bronchial obstruction and increased pulmonary vascular resistance impairs right atrial functions. In this study, we aimed to investigate the effect of bronchial obstruction on p wave axis in patients with COPD and usefulness of electrocardiography (ECG) in the evaluation of the severity of COPD. Ninety five patients (64 male and 31 female) included to the study. Patients were in sinus rhythm, with normal ejection fraction and heart chamber sizes. Their respiratory function tests and 12 lead electrocardiograms were obtained at same day. Correlations with severity of COPD and ECG findings including p wave axis, p wave duration, QRS axis, QRS duration were studied. The mean age was 58 ± 12 years. Their mean p wave axis was 62 ± 18 degrees. In this study, p wave axis has demonstrated significant positive correlations with stages of COPD and QRS axis but significant negative correlations with FEV1, FEF, BMI and QRS duration. P wave axis increases with increasing stages of COPD. Verticalization of the frontal p wave axis may be an early finding of worsening of COPD before occurrences of other ECG changes of hypertrophy and enlargement of right heart chambers such as p pulmonale. Verticalization of the frontal p wave axis reflecting right atrial electrical activity and right heart strain may be a useful parameter for quick estimation of the severity of COPD in an out-patient cared.

Experiment K-7-30: Effects of Spaceflight in the Cosmos Biosatellite 2044 on the Vestibular-Ocular Reflex (VOR) of Rhesus Monkeys

NASA Technical Reports Server (NTRS)

Cohen, B.; Cohen, N.; Helwig, D.; Solomon, D.; Kozlovskaya, I.; Sirota, M.; Yakushin, S.; Raphan, T.

1994-01-01

This technical paper discusses the following: (1) The VOR of two rhesus monkeys was studied before and after 14 days of spaceflight to determine effects of microgravity on the VOR. Horizontal, vertical and roll eye movements were recorded in these and six other monkeys implanted with scleral search coils. Animals were rotated about a vertical axis to determine the gain of the horizontal, vertical and roll VOR. They were rotated about axes tilted from the vertical (off-vertical axis rotation, OVAR) to determine steady state gains and effects of gravity on modulations in eye position and eye velocity. They were also tested for tilt dumping of post-rotatory nystagmus. (2) The gain of the horizontal VOR was close to unity when animals were tested 15 and 18 hours after flight. VOR gain values were similar to those registered before flight. If the gain of the horizontal VOR changes in microgravity, it must revert to normal soon after landing. (3) Steady state velocities of nystagmus induced by off-vertical axis rotation (OVAR) were unchanged by adaptation to microgravity, and the phase of the modulations was similar before and after flight. However, modulations in horizontal eye velocity had more variation after landing and were on mean about 50% larger for angles of tilt of the axis of rotation between 50 and 90?/s after flight. This difference was similar in both animals and was significant. (4) A striking finding was that tilt dumping was lost in the one animal tested for this function. This loss persisted for several days after return. This is reminiscent of the loss of response to pitch while rotating in the M-131 experiments of Skylab, and must be studied in detail in future spaceflights. (5) Thus, two major findings emerged from these studies: after spaceflight the modulation of horizontal eye velocity was larger during OVAR, and one animal lost its ability to tilt-dump its nystagmus. Both findings are consistent with the postulate that adaptation to microgravity causes alterations in the way that otolith information is processed in the central nervous system. The experiments lay the groundwork for studying the vertical and roll VOR before and after future space flights, as well as for studying modulations in vertical and roll eye position during OVAR and tilt dumping.

Mid-humerus adaptation in fast pitch softballers and the impact of throwing mechanics

PubMed Central

Bogenschutz, Elizabeth D.; Smith, Heather D.; Warden, Stuart J.

2011-01-01

Purpose Throwing is a vigorous activity that generates large internal loads. There is limited evidence of the effect of these loads on bone adaptation. The aim of this study was to investigate the: 1) magnitude of bone adaptation within the midshaft humerus of female fast-pitch softball players and 2) influence of throwing mechanics (windmill vs. overhand throwing) on the magnitude of adaptation. Methods Midshaft humeral bone mass, structure and estimated strength were assessed via peripheral quantitative computed tomography in fast-pitch softball players (throwers; n=15) and matched controls (controls; n=15). The effect of throwing was examined by comparing dominant-to-nondominant differences in throwers to controls, while the influence of mechanics was determined by comparing dominant-to-nondominant differences in throwers who primarily play as pitcher (windmill thrower), catcher (overhand thrower) or fielder (overhand thrower). Results Throwers had greater dominant-to-nondominant difference in midshaft humeral bone mass, structure and estimated strength relative to controls (all P<0.05). The largest effect was for estimated torsional strength with throwers having a mean dominant-to-nondominant difference of 22.5% (range, 6.7% to 43.9%) compared to 4.4% (range, -8.3% to 17.5%) in controls (P<0.001). Throwing mechanics appeared to influence the magnitude of skeletal adaptation, with overhand throwers having more than double dominant-to-nondominant difference in midshaft humeral bone mass, structure and estimated strength than windmill throwers (all P<0.05). Conclusion Throwing induces substantial skeletal adaptation at the midshaft humerus of the dominant upper extremity. Throwing mechanics appears to the influence the magnitude of adaptation as catchers and fielders (overhand throwers) had twice as much adaptation as pitchers (windmill throwers). The latter finding may have implications for skeletal injury risk at the midshaft humerus in throwing athletes. PMID:21311354

Development of the vertical Bridgman technique for 6-inch diameter c-axis sapphire growth supported by numerical simulation

NASA Astrophysics Data System (ADS)

Miyagawa, Chihiro; Kobayashi, Takumi; Taishi, Toshinori; Hoshikawa, Keigo

2014-09-01

Based on the growth of 3-inch diameter c-axis sapphire using the vertical Bridgman (VB) technique, numerical simulations were made and used to guide the growth of a 6-inch diameter sapphire. A 2D model of the VB hot-zone was constructed, the seeding interface shape of the 3-inch diameter sapphire as revealed by green laser scattering was estimated numerically, and the temperature distributions of two VB hot-zone models designed for 6-inch diameter sapphire growth were numerically simulated to achieve the optimal growth of large crystals. The hot-zone model with one heater was selected and prepared, and 6-inch diameter c-axis sapphire boules were actually grown, as predicted by the numerical results.

Efficiency of the DOMUS 750 vertical-axis wind turbine

NASA Astrophysics Data System (ADS)

Hallock, Kyle; Rasch, Tyler; Ju, Guoqiang; Alonso-Marroquin, Fernando

2017-06-01

The aim of this paper is to present some preliminary results on the efficiency of a wind turbine for an off-grid housing unit. To generate power, the unit uses a photovoltaic solar array and a vertical-axis wind turbine (VAWT). The existing VAWT was analysed to improve efficiency and increase power generation. There were found to be two main sources of inefficiency: 1. the 750W DC epicyclic generator performed poorly in low winds, and 2. the turbine blades wobbled, allowing for energy loss due to off-axis rotation. A 12V DC permanent magnet alternator was chosen that met the power requirements of the housing unit and would generate power at lower wind speeds. A support bracket was designed to prevent the turbine blades from wobbling.

Paleomagnetic evidence for rapid vertical-axis rotations during thrusting in an active collision zone, northeastern Papua New Guinea

NASA Astrophysics Data System (ADS)

Weiler, Peter D.; Coe, Robert S.

1997-06-01

A paleomagnetic study of three thrust sheets of the fold and thrust belt north of the Ramu-Markham Fault Zone (RMFZ) indicates very rapid vertical-axis rotations, with differential declination anomalies related to tectonic transport of thrust units. Data from this investigation indicate depositional ages straddling the Brunhes-Matuyama reversal (780 ka) for the Leron Formation in Erap Valley. Net counterclockwise, vertical-axis rotations as great as 90° since 1 Ma have occurred locally in the Erap Valley area. These rotations appear to be kinematically related to shear across a tear fault within the foreland fold and thrust belt of the colliding Finisterre Arc, which in turn is aligned with and may be structurally controlled by a major fault in the lower plate. These data indicate that vertical-axis rotations occurred during thrusting; consequently, the actual rotation rate is likely several times higher than the calculated minimum rate. Such very rapid rotations during thrust sheet emplacement may be more common in fold and thrust belts than is presently recognized. Anisotropy of magnetic susceptibility data yields foliated fabrics with subordinate, well-grouped lineations that differ markedly in azimuth in the three thrust sheets. The susceptibility lineations are rendered parallel by the same bedding-perpendicular rotations used to restore the paleomagnetic remanence to N-S thus independently confirming the rapid rotations. The restored lineations are perpendicular to the direction of tectonic transport, and the minimum susceptibility axes are streaked perpendicular to the lineation. We interpret these anisotropy of magnetic susceptibility data as primary sedimentary fabrics modified by weak strain accompanying foreland thrusting.

Are we simplifying balance evaluation in adolescent idiopathic scoliosis?

PubMed

Pasha, Saba; Baldwin, Keith

2018-01-01

Clinical evaluation of the postural balance in adolescent idiopathic scoliosis has been measured by sagittal vertical axis and frontal balance. The impact of the scoliotic deformity in three planes on balance has not been fully investigated. 47 right thoracic and left lumbar curves adolescent idiopathic scoliosis and 10 non-scoliotic controls were registered prospectively. 13 spinopelvic postural parameters were calculated from the 3-dimantional reconstructions of X-rays. 7 balance variables describing the position and sway of the center of pressure were recorded using a pressure mat. A regression analysis was used to predict sagittal vertical axis and frontal balance from the 7 balance variables. A canonical correlation analysis was performed between all the postural parameters and balance variables and the significant associations between the postural and balance variables were determined. sagittal vertical axis and frontal balance were not significantly associated with the position or sway of the center of pressure (p>0.05). Canonical correlation analysis showed significant associations between the postural variables in the 3 planes and center of pressure position (R 2 =0.81) and sway (R 2 =0.62), p<0.05. Frontal Cobbs, apical rotations, distal kyphosis, pelvic incidence, sacral slope, sagittal vertical axis, and frontal balance contributed to the postural balance in the cohort. The compensatory role of the pelvis and distal kyphosis in sagittal plane was underlined. Multidimensional analyses between the postural and balance variables showed the alignment of the thoracic, lumbar, and pelvis in the 3 planes, in addition to the global head-pelvic position impact on adolescent idiopathic scoliosis balance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Observations of Screw Dislocation Driven Growth and Faceting During CVD Homoepitaxy on 4H-SiC On-Axis Mesa Arrays

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Trunek, Andrew J.; Powell, J. Anthony; Picard, Yoosuf N.; Twigg, Mark E.

2009-01-01

Previous studies of (0001) homoepitaxial growth carried out on arrays of small-area mesas etched into on-axis silicon-face 4H-SiC wafers have demonstrated that spiral growth emanating from at least one screw dislocation threading the mesa is necessary in order for a mesa to grow taller in the <0001> (c-axis vertical) direction while maintaining 4H stacking sequence [1]. However, even amongst mesas containing the screw dislocation step source necessary for vertical c-axis growth, we have observed striking differences in the height and faceting that evolve during prolonged homoepitaxial growths. This paper summarizes Atomic Force Microscopy (AFM), Electron Channeling Contrast Imaging (ECCI), Scanning Electron Microscopy (SEM), and optical microscopy observations of this phenomenon. These observations support our initially proposed model [2] that the observed large variation (for mesas where 3C-SiC nucleation has not occurred) is related to the lateral positioning of a screw dislocation step source within each etched mesa. When the screw dislocation step source is located close enough to the developing edge/sidewall facet of a mesa, the c-axis growth rate and facet angle are affected by the resulting interaction. In particular, the intersection (or near intersection) of the inward-sloping mesa sidewall facet with the screw dislocation appears to impede the rate at which the spiral provides new steps required for c-axis growth. Also, the inward slope of the sidewall facet during growth (relative to other sidewalls of the same mesa not near the screw dislocation) seems to be impeded by the screw dislocation. In contrast, mesas whose screw dislocations are centrally located grow vertically, but inward sloping sidewall facets shrink the area of the top (0001) growth surface almost to the point of vanishing.

Temporal Dynamics of Ocular Position Dependence of the Initial Human Vestibulo-ocular Reflex

PubMed Central

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

2007-01-01

Purpose While an ideal vestibulo-ocular reflex (VOR) generates ocular rotations compensatory for head motion, during visually guided movements, Listing’s Law (LL) constrains the eye to rotational axes lying in Listing’s Plane (LP). The present study was conducted to explore the recent proposal that the VOR’s rotational axis is not collinear with the head’s, but rather follows a time-dependent strategy intermediate between LL and an ideal VOR. Methods Binocular LPs were defined during visual fixation in eight normal humans. The VOR was evoked by a highly repeatable transient whole-body yaw rotation in darkness at a peak acceleration of 2800 deg/s2. Immediately before rotation, subjects regarded targets 15 or 500 cm distant located at eye level, 20° up, or 20° down. Eye and head responses were compared with LL predictions in the position and velocity domains. Results LP orientation varied both among subjects and between individual subject’s eyes, and rotated temporally with convergence by 5 ± 5° (±SEM). In the position domain, the eye compensated for head displacement even when the head rotated out of LP. Even within the first 20 ms from onset of head rotation, the ocular velocity axis tilted relative to the head axis by 30% ± 8% of vertical gaze position. Saccades increased this tilt. Regardless of vertical gaze position, the ocular rotation axis tilted backward 4° farther in abduction than in adduction. There was also a binocular vertical eye velocity transient and lateral tilt of the ocular axis. Conclusions These disconjugate, short-latency axis perturbations appear intrinsic to the VOR and may have neural or mechanical origins. PMID:16565376

Interaction of an Artificially Thickened Boundary Layer with a Vertically Mounted Pitching Airfoil

NASA Astrophysics Data System (ADS)

Hohman, Tristen; Smits, Alexander; Martinelli, Luigi

2011-11-01

Wind energy represents a large portion of the growing market in alternative energy technologies and the current landscape has been dominated by the more prevalent horizontal axis wind turbine. However, there are several advantages to the vertical axis wind turbine (VAWT) or Darrieus type design and yet there is much to be understood about how the atmospheric boundary layer (ABL) affects their performance. In this study the ABL was simulated in a wind tunnel through the use of elliptical shaped vortex generators, a castellated wall, and floor roughness elements as described in the method of Counihan (1967) and then verified its validity by hot wire measurement of the mean velocity profile as well as the turbulence intensity. The motion of an blade element around a vertical axis is approximated through the use of a pitching airfoil. The wake of the airfoil is investigated through hot wire anemometry in both uniform flow and in the simulated boundary layer both at Re = 1 . 37 ×105 based on the chord of the airfoil. Sponsored by Hopewell Wind Power (Hong Kong) Limited.

Numerical simulation on a straight-bladed vertical axis wind turbine with auxiliary blade

NASA Astrophysics Data System (ADS)

Li, Y.; Zheng, Y. F.; Feng, F.; He, Q. B.; Wang, N. X.

2016-08-01

To improve the starting performance of the straight-bladed vertical axis wind turbine (SB-VAWT) at low wind speed, and the output characteristics at high wind speed, a flexible, scalable auxiliary vane mechanism was designed and installed into the rotor of SB-VAWT in this study. This new vertical axis wind turbine is a kind of lift-to-drag combination wind turbine. The flexible blade expanded, and the driving force of the wind turbines comes mainly from drag at low rotational speed. On the other hand, the flexible blade is retracted at higher speed, and the driving force is primarily from a lift. To research the effects of the flexible, scalable auxiliary module on the performance of SB-VAWT and to find its best parameters, the computational fluid dynamics (CFD) numerical calculation was carried out. The calculation result shows that the flexible, scalable blades can automatic expand and retract with the rotational speed. The moment coefficient at low tip speed ratio increased substantially. Meanwhile, the moment coefficient has also been improved at high tip speed ratios in certain ranges.

Large Eddy Simulation of Vertical Axis Wind Turbine wakes; Part II: effects of inflow turbulence

NASA Astrophysics Data System (ADS)

Duponcheel, Matthieu; Chatelain, Philippe; Caprace, Denis-Gabriel; Winckelmans, Gregoire

2017-11-01

The aerodynamics of Vertical Axis Wind Turbines (VAWTs) is inherently unsteady, which leads to vorticity shedding mechanisms due to both the lift distribution along the blade and its time evolution. Large-scale, fine-resolution Large Eddy Simulations of the flow past Vertical Axis Wind Turbines have been performed using a state-of-the-art Vortex Particle-Mesh (VPM) method combined with immersed lifting lines. Inflow turbulence with a prescribed turbulence intensity (TI) is injected at the inlet of the simulation from a precomputed synthetic turbulence field obtained using the Mann algorithm. The wake of a standard, medium-solidity, H-shaped machine is simulated for several TI levels. The complex wake development is captured in details and over long distances: from the blades to the near wake coherent vortices, then through the transitional ones to the fully developed turbulent far wake. Mean flow and turbulence statistics are computed over more than 10 diameters downstream of the machine. The sensitivity of the wake topology and decay to the TI level is assessed.

Design, experimental analysis, and unsteady Reynolds-averaged Navier-Stokes simulation of laboratory-scale counter-rotating vertical-axis turbines in marine environment

NASA Astrophysics Data System (ADS)

Doan, Minh; Padricelli, Claudrio; Obi, Shinnosuke; Totsuka, Yoshitaka

2017-11-01

We present the torque and power measurement of laboratory-scale counter-rotating vertical-axis hydrokinetic turbines, built around a magnetic hysteresis brake as the speed controller and a Hall-effect sensor as the rotational speed transducer. A couple of straight-three-bladed turbines were linked through a transmission of spur gears and timing pulleys and coupled to the electronic instrumentation via flexible shaft couplers. A total of 8 experiments in 2 configurations were conducted in the water channel facility (4-m long, 0.3-m wide, and 0.15-m deep). Power generation of the turbines (0.06-m rotor diameter) was measured and compared with that of single turbines of the same size. The wakes generated by these experiments were also measured by particle image velocimetry (PIV) and numerically simulated by unsteady Reynolds-averaged Navier-Stokes (URANS) simulation using OpenFOAM. Preliminary results from wake measurement indicated the mechanism of enhanced power production behind the counter-rotating configuration of vertical-axis turbines. Current address: Politecnico di Milano.

Performance investigation of an innovative Vertical Axis Hydrokinetic Turbine – Straight Blade Cascaded (VAHT-SBC) for low current speed

NASA Astrophysics Data System (ADS)

Hantoro, R.; Prananda, J.; Mahmashani, A. W.; Septyaningru, E.; Imanuddin, F.

2018-05-01

Research on the development and innovation of Vertical Axis Hydrokinetic Turbine (VAHT) to improve performance has been done. One of the important indicator that affects VAHT’s performance is Coefficient of Performance (Cp). Theoretical Cp value for the VAT (Darrieus) turbine is 0.45. This paper presents the results of a performance investigation for an innovative Vertical Axis Hydrokinetic Turbine – Straight Blade Cascaded (VAHT-SBC) by modifying the number and the arrangement of blades using CFD simulation. Symmetrical NACA 0018 is used for this study, each model is simulated with current speed variation (U - m/s) of 0.5, 1 and 1.5. An increase in Cp value is shown in variation of 9 blades (3 blades cascaded in each arm) with Cp value of 0.396 at TSR of 2.27 which is reach 88% of the theoretical value. Furthermore, the streamline velocity of the pressure contour, velocity streamline and torque fluctuations are also presented in this paper to gain in deep information.

Two-dimensional particle-in-cell plasma source ion implantation of a prolate spheroid target

NASA Astrophysics Data System (ADS)

Liu, Cheng-Sen; Han, Hong-Ying; Peng, Xiao-Qing; Chang, Ye; Wang, De-Zhen

2010-03-01

A two-dimensional particle-in-cell simulation is used to study the time-dependent evolution of the sheath surrounding a prolate spheroid target during a high voltage pulse in plasma source ion implantation. Our study shows that the potential contour lines pack more closely in the plasma sheath near the vertex of the major axis, i.e. where a thinner sheath is formed, and a non-uniform total ion dose distribution is incident along the surface of the prolate spheroid target due to the focusing of ions by the potential structure. Ion focusing takes place not only at the vertex of the major axis, where dense potential contour lines exist, but also at the vertex of the minor axis, where sparse contour lines exist. This results in two peaks of the received ion dose, locating at the vertices of the major and minor axes of the prolate spheroid target, and an ion dose valley, staying always between the vertices, rather than at the vertex of the minor axis.

Reviews

NASA Astrophysics Data System (ADS)

2008-11-01

WE RECOMMEND Ideas, Evidence and Argument in Science Fantastic DVD packed with classroom activities LabQuest Datalogger hits all the right buttons The Complete Idiot's Guide to String Theory A book that is better than its title lets on Light Strip SEP proves yet again that simple equipment is best Teaching Radioactivity Multimedia resource gets hands-on with radioactivity WORTH A LOOK Sunshine DVD of the sci-fi film includes insightful commentary track Peltier Cell Unit SEP equipment is useful but unusually pricey 100 Things to Spot in the Night Sky Data cards are packed with astronomical facts Light Sensor SEP unit is only useful for one specific experiment Windmill Generator Classroom-sized windmill does not sell wind power The Number Devil A 'mathematical adventure' book for young children

Mesh control information of windmill designed by Solidwork program

NASA Astrophysics Data System (ADS)

Mulyana, T.; Sebayang, D.; Rafsanjani, A. M. D.; Adani, J. H. D.; Muhyiddin, Y. S.

2017-12-01

This paper presents the mesh control information imposed on the windmill already designed. The accuracy of Simulation results is influenced by the quality of the created mesh. However, compared to the quality of the mesh is made, the simulation time running will be done software also increases. The smaller the size of the elements created when making the mesh, the better the mesh quality will be generated. When adjusting the mesh size, there is a slider that acts as the density regulator of the element. SolidWorks Simulation also has Mesh Control facility. Features that can adjust mesh density only in the desired part. The best results of mesh control obtained for both static and thermal simulation have ratio 1.5.

Gyroscope and Micromirror Design Using Vertical-Axis CMOS-MEMS Actuation and Sensing

DTIC Science & Technology

2002-01-01

Interference pattern around the upper anchor (each fringe occurs at 310 nm vertical displacement...described above require extra lithography step(s) other than standard CMOS lithography steps and/or deposition of structural and sacrificial materials...Instruments’ dig- ital mirror device ( DMD ) [43]. The aluminum thin-film technology with vertical parallel- plate actuation has difficulty in achieving

Wind energy converter with high-speed vertical axis rotor and straight rotor blades

NASA Astrophysics Data System (ADS)

Zelck, G.

1982-11-01

Complete documents for a wind energy converter with a vertical axis rotor and straight blades (H-rotor) were developed. The 2 blade rotor with rigid and rectangular air foils in wooden construction reaches the nominal output of 75 KVA from 11,4 m/sec. wind velocity onwards. The development activities are supported by wind tunnel and component tests. The final design selected was based upon previous development work. Trade offs show that the design is more advantageous compared to other designs. The use of wood as a material for the rotary and horizontal blade supports gives positive result.

Finite-element analysis and modal testing of a rotating wind turbine

NASA Astrophysics Data System (ADS)

Carne, T. G.; Lobitz, D. W.; Nord, A. R.; Watson, R. A.

1982-10-01

A finite element procedure, which includes geometric stiffening, and centrifugal and Coriolis terms resulting from the use of a rotating coordinate system, was developed to compute the mode shapes and frequencies of rotating structures. Special applications of this capability was made to Darrieus, vertical axis wind turbines. In a parallel development effort, a technique for the modal testing of a rotating vertical axis wind turbine is established to measure modal parameters directly. Results from the predictive and experimental techniques for the modal frequencies and mode shapes are compared over a wide range of rotational speeds.

Finite element analysis and modal testing of a rotating wind turbine

NASA Astrophysics Data System (ADS)

Carne, T. G.; Lobitz, D. W.; Nord, A. R.; Watson, R. A.

A finite element procedure, which includes geometric stiffening, and centrifugal and Coriolis terms resulting from the use of a rotating coordinate system, has been developed to compute the mode shapes and frequencies of rotating structures. Special application of this capability has been made to Darrieus, vertical axis wind turbines. In a parallel development effort, a technique for the modal testing of a rotating vertical axis wind turbine has been established to measure modal parameters directly. Results from the predictive and experimental techniques for the modal frequencies and mode shapes are compared over a wide range of rotational speeds.

A 34-meter VAWT (Vertical Axis Wind Turbine) point design

NASA Astrophysics Data System (ADS)

Ashwill, T. D.; Berg, D. E.; Dodd, H. M.; Rumsey, M. A.; Sutherland, H. J.; Veers, P. S.

The Wind Energy Division at Sandia National Laboratories recently completed a point design based on the 34-m Vertical Axis Wind Turbine (VAWT) Test Bed. The 34-m Test Bed research machine incorporates several innovations that improve Darrieus technology, including increased energy production, over previous machines. The point design differs minimally from the Test Bed; but by removing research-related items, its estimated cost is substantially reduced. The point design is a first step towards a Test-Bed-based commercial machine that would be competitive with conventional sources of power in the mid-1990s.

Design and fabrication of a low-cost Darrieus vertical-axis wind-turbine system, phase 2. Volume 3: Design, fabrication, and site drawing

NASA Astrophysics Data System (ADS)

1983-03-01

The design, fabrication, and site drawings associated with fabrication, installation, and check out of 100 kW 17 meter Vertical Axis Wind Turbines (VAWTs) were reported. The turbines are Darrieus type VAWTs with rotors 17 meters in diameter and 25.15 meters in height. They can produce 100 kW of electric power at a cost of energy as low as 3 cents per kWh, in an 18 mph wind regime using 12% annualized costs. Four turbines are produced, three are installed and operable.

Rotor instrumentation circuits for the Sandia 34-meter vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Sutherland, Herbert J.; Stephenson, William A.

1988-07-01

Sandia National Laboratories has erected a research oriented, 34-meter diameter, Darrieus vertical axis wind turbine near Bushland, Texas, which has been designated the Sandia 34-m VAWT Test Bed. To meet present and future research needs, the machine was equipped with a large array of sensors. This manuscript details the sensors initially placed on the rotor, their respective instrumentation circuits, and the provisions incorporated into the design of the rotor instrumentation circuits for future research. This manuscript was written as a reference manual for the rotor instrumentation of the Test Bed.

Design, performance, and economics of 50-kW and 500-kW vertical axis wind turbines

NASA Astrophysics Data System (ADS)

Schienbein, L. A.; Malcolm, D. J.

1983-11-01

A review of the development and performance of the DAF Indal 50-kW vertical axis Darrieus wind turbine shows that a high level of technical development and reliability has been achieved. Features of the drive train, braking and control systems are discussed and performance details are presented. Details are also presented of a 500-kW VAWT that is currently in production. A discussion of the economics of both the 50-kW and 500-kW VAWTs is included, showing the effects of charge rate, installed cost, operating cost, performance, and efficiency.

Vertical axis wind turbine drive train transient dynamics

NASA Technical Reports Server (NTRS)

Clauss, D. B.; Carne, T. G.

1982-01-01

Start up of a vertical axis wind turbine causes transient torque oscillations in the drive train with peak torques which may be over two and one half times the rated torque of the turbine. A computer code, based on a lumped parameter model of the drive train, was developed and tested for the low cost 17 meter turbine; the results show excellent agreement with field data. The code was used to predict the effect of a slip clutch on transient torque oscillations. It was demonstrated that a slip clutch located between the motor and brake can reduce peak torques by thirty eight percent.

Results of a utility survey of the status of large wind turbine development

NASA Technical Reports Server (NTRS)

Watts, A.; Quraeshi, S.; Rowley, L. P.

1979-01-01

Wind energy conversion systems were surveyed from a utility viewpoint to establish the state of the art with regard to: (1) availability of the type of machines; (2) quality of power generation; (3) suitability for electrical grid; (4) reliability; and (5) economics. Of the 23 designs discussed, 7 have vertical axis wind turbines, 9 have upwind horizontal axis turbines, and 7 have downwind horizontal axis turbines.

Modelling resonances of the standing body exposed to vertical whole-body vibration: Effects of posture

NASA Astrophysics Data System (ADS)

Subashi, G. H. M. J.; Matsumoto, Y.; Griffin, M. J.

2008-10-01

Lumped parameter mathematical models representing anatomical parts of the human body have been developed to represent body motions associated with resonances of the vertical apparent mass and the fore-and-aft cross-axis apparent mass of the human body standing in five different postures: 'upright', 'lordotic', 'anterior lean', 'knees bent', and 'knees more bent'. The inertial and geometric parameters of the models were determined from published anthropometric data. Stiffness and damping parameters were obtained by comparing model responses with experimental data obtained previously. The principal resonance of the vertical apparent mass, and the first peak in the fore-and-aft cross-axis apparent mass, of the standing body in an upright posture (at 5-6 Hz) corresponded to vertical motion of the viscera in phase with the vertical motion of the entire body due to deformation of the tissues at the soles of the feet, with pitch motion of the pelvis out of phase with pitch motion of the upper body above the pelvis. Upward motion of the body was in phase with the forward pitch motion of the pelvis. Changing the posture of the upper body had minor effects on the mode associated with the principal resonances of the apparent mass and cross-axis apparent mass, but the mode changed significantly with bending of the legs. In legs-bent postures, the principal resonance (at about 3 Hz) was attributed to bending of the legs coupled with pitch motion of the pelvis in phase with pitch motion of the upper body. In this mode, extension of the legs was in phase with the forward pitch motion of the upper body and the upward vertical motion of the viscera.

The effect of vertical and horizontal symmetry on memory for tactile patterns in late blind individuals.

PubMed

Cattaneo, Zaira; Vecchi, Tomaso; Fantino, Micaela; Herbert, Andrew M; Merabet, Lotfi B

2013-02-01

Visual stimuli that exhibit vertical symmetry are easier to remember than stimuli symmetric along other axes, an advantage that extends to the haptic modality as well. Critically, the vertical symmetry memory advantage has not been found in early blind individuals, despite their overall superior memory, as compared with sighted individuals, and the presence of an overall advantage for identifying symmetric over asymmetric patterns. The absence of the vertical axis memory advantage in the early blind may depend on their total lack of visual experience or on the effect of prolonged visual deprivation. To disentangle this issue, in this study, we measured the ability of late blind individuals to remember tactile spatial patterns that were either vertically or horizontally symmetric or asymmetric. Late blind participants showed better memory performance for symmetric patterns. An additional advantage for the vertical axis of symmetry over the horizontal one was reported, but only for patterns presented in the frontal plane. In the horizontal plane, no difference was observed between vertical and horizontal symmetric patterns, due to the latter being recalled particularly well. These results are discussed in terms of the influence of the spatial reference frame adopted during exploration. Overall, our data suggest that prior visual experience is sufficient to drive the vertical symmetry memory advantage, at least when an external reference frame based on geocentric cues (i.e., gravity) is adopted.

A new wind energy conversion system

NASA Technical Reports Server (NTRS)

Smetana, F. O.

1975-01-01

It is presupposed that vertical axis wind energy machines will be superior to horizontal axis machines on a power output/cost basis and the design of a new wind energy machine is presented. The design employs conical cones with sharp lips and smooth surfaces to promote maximum drag and minimize skin friction. The cones are mounted on a vertical axis in such a way as to assist torque development. Storing wind energy as compressed air is thought to be optimal and reasons are: (1) the efficiency of compression is fairly high compared to the conversion of mechanical energy to electrical energy in storage batteries; (2) the release of stored energy through an air motor has high efficiency; and (3) design, construction, and maintenance of an all-mechanical system is usually simpler than for a mechanical to electrical conversion system.

7 CFR 42.141 - Obtaining Operating Characteristic (OC) curve information for skip lot sampling and inspection.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., and read the new Percent of Lots Expected to be Accepted, Pas, which results when using these skip lot... point, proceed vertically to the curve and then horizontally to the left to the vertical axis. From this...

7 CFR 42.141 - Obtaining Operating Characteristic (OC) curve information for skip lot sampling and inspection.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., and read the new Percent of Lots Expected to be Accepted, Pas, which results when using these skip lot... point, proceed vertically to the curve and then horizontally to the left to the vertical axis. From this...

Preservation of vestibular function after scala vestibuli cochlear implantation.

PubMed

Suzuki, Mitsuya; Goto, Takio; Kashio, Akinori; Yasui, Takuya; Sakamoto, Takashi; Ito, Ken; Yamasoba, Tatsuya

2011-10-01

A 58-year-old man, in whom the cochlear implant (CI) had been inserted into the left ear, had right middle-ear cancer. The CI was removed immediately before receiving subtotal removal of right temporal bone. Four months later, the CI was again inserted in his left cochlea. Because of obliterated scala tympani, the 22 active electrodes of the CI were placed into the scala vestibuli. After the surgery, the patient complained that he experienced rotary vertigo and "jumbling of vertical direction" of objects on walking. Using rotation test, we evaluated vestibular function of remaining left ear. Numerous horizontal nystagmus beats were induced during earth-vertical axis rotation, whereas vertical downbeat nystagmus was scarcely induced during off-vertical axis rotation. The horizontal vestibulo-ocular reflex (VOR) was almost normally induced by sinusoidal stimulation at 0.8Hz. These data suggest that the scala vestibuli insertion of CI would be not so invasive against the lateral semicircular canal. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Perception of Invariance Over Perspective Transformations in Five Month Old Infants.

ERIC Educational Resources Information Center

Gibson, Eleanor; And Others

This experiment asked whether infants at 5 months perceived an invariant over four types of rigid motion (perspective transformations), and thereby differentiated rigid motion from deformation. Four perspective transformations of a sponge rubber object (rotation around the vertical axis, rotation around the horizontal axis, rotation in the frontal…

Rare cause of knee pain after martial arts demonstration: a case report.

PubMed

Armstrong, Marc B; Thurber, Jalil

2013-04-01

Patellar dislocations are a commonly treated injury in the Emergency Department (ED), with a majority of cases involving lateral subluxation of the patella outside of the joint space. Intra-condylar dislocations of the patella are rare. Of the two types of axis rotation, vertical and horizontal, the vertical occurs five times less frequently. These injuries most often undergo open reduction or, at best, closed reduction under general anesthesia. To remind Emergency Physicians to consider this injury in any patient with severe knee pain and limited mobility, even with a history that is lacking significant trauma. We present a case of intra-condylar patellar dislocation with vertical axis rotation. This injury is no longer primarily attributed to the young and, barring fracture, closed reduction in the ED should be considered. Copyright © 2013 Elsevier Inc. All rights reserved.

Perceptual simulation in gender categorization: associations between gender, vertical height, and spatial size.

PubMed

Zhang, Xiaobin; Li, Qiong; Eskine, Kendall J; Zuo, Bin

2014-01-01

The current studies extend perceptual symbol systems theory to the processing of gender categorization by revealing that gender categorization recruits perceptual simulations of spatial height and size dimensions. In study 1, categorization of male faces were faster when the faces were in the "up" (i.e., higher on the vertical axis) rather than the "down" (i.e., lower on the vertical axis) position and vice versa for female face categorization. Study 2 found that responses to male names depicted in larger font were faster than male names depicted in smaller font, whereas opposite response patterns were given for female names. Study 3 confirmed that the effect in Study 2 was not due to metaphoric relationships between gender and social power. Together, these findings suggest that representation of gender (social categorization) also involves processes of perceptual simulation.

The Energy Crisis: Is It Fabrication or Miscalculation?

ERIC Educational Resources Information Center

Shaheen, Esber I.

1974-01-01

Issues surrounding the recent oil shortages are discussed and alternate sources reviewed are nuclear power, fusion, solar energy, geothermal energy, magnetohydrodynamics coal gasification, windmills and tidal power. (JP)

The multi-axis vibration environment and man.

PubMed

Lovesey, E J

1970-12-01

Many investigations into the effects of vibration on man have been performed since Mallock's first study of London Underground vibrations in 1902. The vibration research has tended to be confined to the vertical (heave) axis, yet recent experiments have indicated that low frequency vibration along the lateral (sway) axis has a greater adverse effect upon comfort and performance. Measurements of the vibration environments in current forms of transport including motor vehicles, hovercraft and aircraft etc have shown that appreciable quantities of vibration along all three axes exist. Further vibration research should consider the effects of multi-axis vibrations upon man rather than limit tests to single axis vibration.

Economic analysis of Darrieus vertical axis wind turbine systems for the generation of utility grid electrical power. Volume IV. Summary and analysis of the A. T. Kearney and Alcoa Laboratories point design economic studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, W.N.; Nellums, R.O.

1979-08-01

The A.T. Kearney and Alcoa economic studies are two independent attempts to assess the installed costs of a series of six Darrieus vertical axis wind turbine designs. The designs cover a range of sizes with peak outputs from 10 to 1600 kW. All are designed to produce utility grid electrical power. Volume IV of this report summarizes, compares, and analyzes the results of these studies. The Kearney and Alcoa final reports are included in the Appendices.

Economic analysis of Darrieus vertical axis wind turbine systems for the generation of utility grid electrical power. Volume IV: summary and analysis of the A. T. Kearney and Alcoa Laboratories point design economic studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, W.N.; Nellums, R.O.

1979-08-01

The A. T. Kearney and Alcoa economic studies are two independent attempts to assess the installed costs of a series of six Darrieus vertical axis wind turbine designs. The designs cover a range of sizes with peak outputs from 10 to 1600 kW. All are designed to produce utility grid electrical power. Volume IV of this report summarizes, compares, and analyzes the results of these studies. The Kearney and Alcoa final reports are included in the Appendices.

A method of calculation on the airloading of vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Azuma, A.; Kimura, S.

A new method of analyzing the aerodynamic characteristics of the Darrieus Vertical-Axis Wind Turbine (VAWT) by applying the local circulation method is described. The validity of this method is confirmed by analyzing the air load acting on a curved blade. The azimuthwise variation of spanwise airloading, torque, and longitudinal forces are accurately calculated for a variety of operational conditions. The results are found to be in good agreement with experimental ones obtained elsewhere. It is concluded that the present approach can calculate the aerodynamic characteristics of the VAWT with much less computational time than that used by the free vortex model.

Speed and Torque Control Strategies for Loss Reduction of Vertical Axis Wind Turbines

NASA Astrophysics Data System (ADS)

Argent, Michael; McDonald, Alasdair; Leithead, Bill; Giles, Alexander

2016-09-01

This paper builds on the work into modelling the generator losses for Vertical Axis Wind Turbines from their intrinsic torque cycling to investigate the effects of aerodynamic inefficiencies caused by the varying rotational speed resulting from different torque control strategies to the cyclic torque. This is achieved by modelling the wake that builds up from the rotation of the VAWT rotor to investigate how the wake responds to a changing rotor speed and how this in turn affects the torque produced by the blades as well as the corresponding change in generator losses and any changes to the energy extracted by the wind turbine rotor.

Dynamic Analysis of Darrieus Vertical Axis Wind Turbine Rotors

NASA Technical Reports Server (NTRS)

Lobitz, D. W.

1981-01-01

The dynamic response characteristics of the vertical axis wind turbine (VAWT) rotor are important factors governing the safety and fatigue life of VAWT systems. The principal problems are the determination of critical rotor speeds (resonances) and the assessment of forced vibration response amplitudes. The solution to these problems is complicated by centrifugal and Coriolis effects which can have substantial influence on rotor resonant frequencies and mode shapes. The primary tools now in use for rotor analysis are described and discussed. These tools include a lumped spring mass model (VAWTDYN) and also finite-element based approaches. The accuracy and completeness of current capabilities are also discussed.

HIGH TEMPERATURE, HIGH POWER HETEROGENEOUS NUCLEAR REACTOR

DOEpatents

Hammond, R.P.; Wykoff, W.R.; Busey, H.M.

1960-06-14

A heterogeneous nuclear reactor is designed comprising a stationary housing and a rotatable annular core being supported for rotation about a vertical axis in the housing, the core containing a plurality of radial fuel- element supporting channels, the cylindrical empty space along the axis of the core providing a central plenum for the disposal of spent fuel elements, the core cross section outer periphery being vertically gradated in radius one end from the other to provide a coolant duct between the core and the housing, and means for inserting fresh fuel elements in the supporting channels under pressure and while the reactor is in operation.

Enhancement of phototropic response to a range of light doses in Triticum aestivum coleoptiles in clinostat-simulated microgravity

NASA Technical Reports Server (NTRS)

Heathcote, D. G.; Bircher, B. W.; Brown, A. H. (Principal Investigator)

1987-01-01

The phototropic dose-response relationship has been determined for Triticum aestivum cv. Broom coleoptiles growing on a purpose-built clinostat apparatus providing gravity compensation by rotation about a horizontal axis at 2 rev min-1. These data are compared with data sets obtained with the clinostat axis vertical and stationary, as a 1 g control, and rotating vertically to examine clinostat effects other than gravity compensation. Triticum at 1 g follows the well-established pattern of other cereal coleoptiles with a first positive curvature at low doses, followed by an indifferent response region, and a second positive response at progressively increasing doses. However, these response regions lie at higher dose levels than reported for Avena. There is no significant difference between the responses observed with the clinostat axis vertical in the rotating and stationary modes, but gravity compensation by horizontal rotation increases the magnitude of first and second positive curvatures some threefold at 100 min after stimulation. The indifferent response is replaced by a significant curvature towards the light source, but remains apparent as a reduced curvature response at these dose levels.

Investigation of the effect of inflow turbulence on vertical axis wind turbine wakes

NASA Astrophysics Data System (ADS)

Chatelain, P.; Duponcheel, M.; Zeoli, S.; Buffin, S.; Caprace, D.-G.; Winckelmans, G.; Bricteux, L.

2017-05-01

The aerodynamics of Vertical Axis Wind Turbines (VAWTs) is inherently unsteady, which leads to vorticity shedding mechanisms due to both the lift distribution along the blade and its time evolution. In this paper, we perform large-scale, fine-resolution Large Eddy Simulations of the flow past Vertical Axis Wind Turbines by means of a state-of-the-art Vortex Particle-Mesh (VPM) method combined with immersed lifting lines. Inflow turbulence with a prescribed turbulence intensity (TI) is injected at the inlet of the simulation either from a precomputed synthetic turbulence field obtained using the Mann algorithm [1] or generated on the-fly using time-correlated synthetic velocity planes. The wake of a standard, medium-solidity, H-shaped machine is simulated for several TI levels. The complex wake development is captured in details and over long distances: from the blades to the near wake coherent vortices, then through the transitional ones to the fully developed turbulent far wake. Mean flow and turbulence statistics are computed over more than 10 diameters downstream of the machine. The sensitivity of the wake topology and decay to the TI and to the operating conditions is then assessed.

Analysis of stiffness and stress in I-bar clasps.

PubMed

Sato, Y; Tsuga, K; Abe, Y; Asahara, S; Akagawa, Y

2001-06-01

An I-bar clasp is one of the most popular direct retainers for distal-extension removable partial dentures. However, no adequate information is available on the shape associated with biomechanics. This study aimed (1) to establish a three-dimensional (3D) finite-element modelling method of I-bar clasps, and (2) to clarify the effect of the shape on the stress and stiffness of I-bar clasps. 3D computer models of I-bar clasps were created with vertical and horizontal straight sections connected with a curved section with six parameters: thickness of the clasp tip (T), width of the clasp tip (W), radius of the curvature (R), horizontal distance between the base and the vertical axis (H), vertical dimension between the tip and the horizontal axis (V), taper (change of width per unit length along the axis)(Tp). Stress decreased as T, W, R and Tp increased, and as V decreased. Stiffness (which is proportional to retention) increased as T, W, R and Tp increased, and as H and V decreased. In both stress and stiffness, the effects of T and Tp were especially large. From the results, a systematic formula between the clasp shape and the stiffness was derived.

Finite element analysis on preferable I-bar clasp shape.

PubMed

Sato, Y; Tsuga, K; Abe, Y; Asahara, S; Akagawa, Y

2001-05-01

An I-bar clasp is one of the most popular direct retainers for distal-extension removable partial dentures. However, no adequate information is available on preferable shape as determined by biomechanics. This study aimed (1) to investigate, by finite element analysis (FEA), the dimensions and stress of I-bar clasps having the same stiffness, and (2) to estimate a mechanically preferable clasp design. Three-dimensional FEA models of I-bar clasps were created with vertical and horizontal straight sections connected by a curved section characterized by six parameters: thickness of the clasp tip, width of the clasp tip, radius of the curvature, horizontal distance between the base and the vertical axis, vertical dimension between the tip and the horizontal axis, and taper (change of width per unit length along the axis). Stress was calculated with a concentrated load of 5 N applied 2 mm from the tip of the clasp in the buccal direction. A thinner and wider clasp having an taper of 0.020-0.023 and radius of curvature of 2.75-3.00 showed less stress. The results suggest that such a shape might be the preferable I-bar clasp shape as biomechanical viewpoint.

Paleomagnetic, structural, and seismological evidence for oblique-slip deformation in fault-related folds in the Rocky Mountain Foreland, Colorado Plateau, and central Coast Ranges

NASA Astrophysics Data System (ADS)

Tetreault, Joya Liana

The two geologic questions I address in this research are: do fault-related folds accommodate oblique-slip shortening, and how is oblique-slip deformation absorbed within the folded strata? If the strata is deforming as a strike-slip shear zone, then we should be able to observe material rotations produced by strike-slip shear by measuring paleomagnetic vertical-axis rotations. I have approached these problems by applying paleomagnetic vertical-axis rotations, minor fault analyses, and focal mechanism strain inversions to identify evidence of strike-slip shear and to quantify oblique-slip deformation within fault-related folds in the Rocky Mountain Foreland, Colorado Plateau, and the central Coast Ranges. Clockwise paleomagnetic vertical-axis rotations and compressive paleostress rotations of 15-40º in the forelimb of the Grayback Monocline, northeastern Front Range Colorado, indicate that this Laramide fold is absorbing right-lateral shear from a N90E regional shortening direction. This work shows that paleomagnetic vertical-axis rotations in folded strata can be used to identify strike-slip motion on an underlying fault, and that oblique-slip deformation is localized in the forelimb of the fold. I applied the same paleomagnetic methods to identify oblique-slip on the underlying faults of the Nacimiento, East Kaibab, San Rafael, and Grand Hogback monoclines of the Colorado Plateau. The absence of paleomagnetic rotations and structural evidence for small displacements at the Nacimiento and East Kaibab monoclines indicate minor (<1km) right-lateral slip is being accommodated in these folds. Paleomagnetic vertical-axis rotations are found in the forelimbs of the San Rafael and Grand Hogback monoclines, yielding strike-slip displacements of ˜5km within these two folds. These results are consistent with a northeast Laramide compressive stress direction. In the Coalinga anticline, central Coast Ranges, California, clockwise paleomagnetic rotations and an 8º counterclockwise deflection of the maximum shortening direction (derived from focal mechanisms strain inversions of the upper 7km) are compatible with right-lateral shear. The maximum shortening direction in the area of the mainshock rupture is fold-normal, indicating that strike-slip displacement is confined to the main fault plane and not distributed to the hanging wall. The San Andreas Fault is therefore partitioning a small amount of strike-slip to the Coalinga anticline.

Axis of Eye Rotation Changes with Head-Pitch Orientation during Head Impulses about Earth-Vertical

PubMed Central

Schubert, Michael C.; Clendaniel, Richard A.; Carey, John P.; Della Santina, Charles C.; Minor, Lloyd B.; Zee, David S.

2006-01-01

The goal of this study was to assess how the axis of head rotation, Listing's law, and eye position influence the axis of eye rotation during brief, rapid head rotations. We specifically asked how the axis of eye rotation during the initial angular vestibuloocular reflex (VOR) changed when the pitch orientation of the head relative to Earth-vertical was varied, but the initial position of the eye in the orbit and the orientation of Listing's plane with respect to the head were fixed. We measured three-dimensional eye and head rotation axes in eight normal humans using the search coil technique during head-and-trunk (whole-body) and head-on-trunk (head-only) “impulses” about an Earth-vertical axis. The head was initially oriented at one of five pitch angles (30° nose down, 15° nose down, 0°, 15° nose up, 30° nose up). The fixation target was always aligned with the nasooccipital axis. Whole-body impulses were passive, unpredictable, manual, rotations with peak-amplitude of ∼20°, peak-velocity of ∼80°/s, and peak-acceleration of ∼1000°/s2. Head-only impulses were also passive, unpredictable, manual, rotations with peak-amplitude of ∼20°, peak-velocity of ∼150°/s, and peak-acceleration of ∼3000°/s2. During whole-body impulses, the axis of eye rotation tilted in the same direction, and by an amount proportional (0.51 ± 0.09), to the starting pitch head orientation (P < 0.05). This proportionality constant decreased slightly to 0.39 ± 0.08 (P < 0.05) during head-only impulses. Using the head-only impulse data, with the head pitched up, we showed that only 50% of the tilt in the axis of eye rotation could be predicted from vectorial summation of the gains (eye velocity/head velocity) obtained for rotations about the pure yaw and roll head axes. Thus, even when the orientation of Listing's plane and eye position in the orbit are fixed, the axis of eye rotation during the VOR reflects a compromise between the requirements of Listing's law and a perfectly compensatory VOR. PMID:16552499

Three-dimensional spatial cognition in a benthic fish, Corydoras aeneus.

PubMed

Davis, V A; Holbrook, R I; Schumacher, S; Guilford, T; de Perera, T Burt

2014-11-01

The way animals move through space is likely to affect the way they learn and remember spatial information. For example, a pelagic fish, Astyanax fasciatus, moves freely in vertical and horizontal space and encodes information from both dimensions with similar accuracy. Benthic fish can also move with six degrees of freedom, but spend much of their time travelling over the substrate; hence they might be expected to prioritise the horizontal dimension. To understand how benthic fish encode and deploy three-dimensional spatial information we used a fully rotational Y-maze to test whether Corydoras aeneus (i) encode space as an integrated three-dimensional unit or as separate elements, by testing whether they can decompose a three-dimensional trajectory into its vertical and horizontal components, and (ii) whether they prioritise vertical or horizontal information when the two conflict. In contradiction to the expectation generated by our hypothesis, our results suggest that C. aeneus are better at extracting vertical information than horizontal information from a three-dimensional trajectory, suggesting that the vertical axis is learned and remembered robustly. Our results also showed that C. aeneus prioritise vertical information when it conflicts with horizontal information. From these results, we infer that benthic fish attend preferentially to a cue unique to the vertical axis, and we suggest that this cue is hydrostatic pressure. Copyright © 2014 Elsevier B.V. All rights reserved.

33 CFR 159.107 - Rolling test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... liquid retention components, if any, filled with water to half of their volume, must be subjected to 100 cycles with the axis of rotation 4 feet from the centerline of the device, no more than 6 inches below... rotated 90 degrees on its vertical axis and subjected to another 100 cycles. This testing must be repeated...

33 CFR 159.107 - Rolling test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... liquid retention components, if any, filled with water to half of their volume, must be subjected to 100 cycles with the axis of rotation 4 feet from the centerline of the device, no more than 6 inches below... rotated 90 degrees on its vertical axis and subjected to another 100 cycles. This testing must be repeated...

33 CFR 159.107 - Rolling test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... liquid retention components, if any, filled with water to half of their volume, must be subjected to 100 cycles with the axis of rotation 4 feet from the centerline of the device, no more than 6 inches below... rotated 90 degrees on its vertical axis and subjected to another 100 cycles. This testing must be repeated...

33 CFR 159.107 - Rolling test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... liquid retention components, if any, filled with water to half of their volume, must be subjected to 100 cycles with the axis of rotation 4 feet from the centerline of the device, no more than 6 inches below... rotated 90 degrees on its vertical axis and subjected to another 100 cycles. This testing must be repeated...

Let's Have Some Capatence Here

ERIC Educational Resources Information Center

Brown, Reva Berman; McCartney, Sean

2003-01-01

Defines two competitive ideas--competence and capability--and argues that neither deals adequately with the central issue of the present. Provides a model, to place these ideas in conceptual space--the vertical axis of which is bounded by the extremes of narrow and broad focus, and the horizontal axis by the past and the future. Suggests that…

Blade pitch optimization methods for vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Kozak, Peter

Vertical-axis wind turbines (VAWTs) offer an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates safety and noise concerns, potentially allowing for installation closer to populated and ecologically sensitive areas. While VAWTs do offer significant operational advantages, development has been hampered by the difficulty of modeling the aerodynamics involved, further complicated by their rotating geometry. This thesis presents results from a simulation of a baseline VAWT computed using Star-CCM+, a commercial finite-volume (FVM) code. VAWT aerodynamics are shown to be dominated at low tip-speed ratios by dynamic stall phenomena and at high tip-speed ratios by wake-blade interactions. Several optimization techniques have been developed for the adjustment of blade pitch based on finite-volume simulations and streamtube models. The effectiveness of the optimization procedure is evaluated and the basic architecture for a feedback control system is proposed. Implementation of variable blade pitch is shown to increase a baseline turbine's power output between 40%-100%, depending on the optimization technique, improving the turbine's competitiveness when compared with a commercially-available horizontal-axis turbine.

Optical levitation of a non-spherical particle in a loosely focused Gaussian beam.

PubMed

Chang, Cheong Bong; Huang, Wei-Xi; Lee, Kyung Heon; Sung, Hyung Jin

2012-10-08

The optical force on a non-spherical particle subjected to a loosely focused laser beam was calculated using the dynamic ray tracing method. Ellipsoidal particles with different aspect ratios, inclination angles, and positions were modeled, and the effects of these parameters on the optical force were examined. The vertical component of the optical force parallel to the laser beam axis decreased as the aspect ratio decreased, whereas the ellipsoid with a small aspect ratio and a large inclination angle experienced a large vertical optical force. The ellipsoids were pulled toward or repelled away from the laser beam axis, depending on the inclination angle, and they experienced a torque near the focal point. The behavior of the ellipsoids in a viscous fluid was examined by analyzing a dynamic simulation based on the penalty immersed boundary method. As the ellipsoids levitated along the direction of the laser beam propagation, they moved horizontally with rotation. Except for the ellipsoid with a small aspect ratio and a zero inclination angle near the focal point, the ellipsoids rotated until the major axis aligned with the laser beam axis.

Wind/water energy converter

NASA Technical Reports Server (NTRS)

Paulkovich, J.

1979-01-01

Device will convert wind, water, tidal or wave energy into electrical or mechanical energy. Is comprised of windmill-like paddles or blades synchronously geared to orient themselves to wind direction for optimum energy extraction.

Longitudinal Stability Characteristics of the Consolidated Vultee XFY-1 Airplane with Windmilling Propellers as Obtained from Flight of 0.133-Scale Rocket-Propelled Model at Mach Numbers from 0.70 to 1.13

NASA Technical Reports Server (NTRS)

Hastings, Earl C.; Mitcham, Grady L.

1954-01-01

A flight test has been conducted to determine the longitudinal stability and control characteristics of a 0.133-scale model of the Consolidated Vultee XFY-1 airplane with windmilling propellers for the Mach number range between 0.70 and 1.13. The variation of lift-curve slope C(sub L(sub alpha) with Mach number was gradual with a maximum value of 0.074 occurring at a Mach number of 0.97. Propellers had little effect upon the values of lift-curve slope or the linearity of lift coefficient with angle of attack. At lift coefficients between approximately 0.25 and 0.45 with an elevon angle of approximately -l0 deg, there was a region of neutral longitudinal stability at Mach numbers below 0.93 introduced by the addition of windmilling propellers. Below a lift coefficient of 0.10 and above a lift coefficient of 0.45, the model was longitudinally stable throughout the Mach number range of the test. There was a forward shift in the aerodynamic center of about 3-percent mean aerodynamic chord introduced by the addition of propellers. The aerodynamic center as determined at low lift moved gradually from a value of 28.5-percent mean aerodynamic chord at a Mach number of 0.75 to a value of 47-percent mean aerodynamic chord at a Mach number of 1.10. There was an abrupt decrease in pitch damping between Mach numbers of 0.88 and 0.99 followed by a rapid increase in damping to a Mach number of 1.06. The propellers had little effect upon the pitch damping characteristics . The transonic trim change was a large pitching-down tendency with and without windmilling propellers. The elevons were effective pitch controls throughout the speed range; however, their effectiveness was reduced about 50 percent at supersonic speeds. The propellers had no appreciable effect upon the control effectiveness.

Framework fluxionality of organometallic oxides: synthesis, crystal structure, EXAFS, and DFT studies on [[Ru(eta6-arene)]4Mo4O16] complexes.

PubMed

Laurencin, Danielle; Garcia Fidalgo, Eva; Villanneau, Richard; Villain, Françoise; Herson, Patrick; Pacifico, Jessica; Stoeckli-Evans, Helen; Bénard, Marc; Rohmer, Marie-Madeleine; Süss-Fink, Georg; Proust, Anna

2004-01-05

Reactions of the molybdates Na(2)MoO4.2 H2O and (nBu(4)N)2[Mo2O7] with [[Ru(arene)Cl(2)](2)] (arene=C(6)H5CH3, 1,3,5-C6H3(CH3)(3), 1,2,4,5-C6H2(CH3)4) in water or organic solvents led to formation of the triple-cubane organometallic oxides [[Ru(eta(6)-arene)](4)Mo4O16], whose crystal and molecular structures were determined. Refluxing triple cubane [[Ru(eta(6)-C6H5CH3)](4)Mo4O16] in methanol caused partial isomerization to the windmill form. The two isomers of [[Ru(eta(6)-C6H5CH3)](4)Mo4O16] were characterized by Raman and Mo K-edge X-ray absorption spectroscopy (XAS), both in the solid-state and in solution. This triple-cubane isomer was also used as a spectroscopic model to account for isomerization of the p-cymene windmill [[Ru(eta(6)-1,4-CH3C6H4CH(CH3)2)](4)Mo4O16] in solution. Using both Raman and XAS techniques, we were then able to determine the ratio between the windmill and triple-cubane isomers in dichloromethane and in chloroform. Density functional calculations on [[Ru(eta(6)-arene)](4)Mo4O16] (arene=C6H6, C6H5CH3, 1,3,5-C6H3(CH3)3, 1,4-CH3C6H4CH(CH3)2, C6(CH3)6) suggest that the windmill form is intrinsically more stable, provided the complexes are assumed to be isolated. Intramolecular electrostatic interactions and steric bulk induced by substituted arenes were found to modulate but not to reverse the energy difference between the isomers. The stability of the triple-cubane isomers should therefore be accounted for by effects of the surroundings that induce a shift in the energy balance between both forms.

Parabrachial nucleus neuronal responses to off-vertical axis rotation in macaques

PubMed Central

McCandless, Cyrus H.; Balaban, Carey D.

2010-01-01

The caudal aspect of the parabrachial nucleus (PBN) contains neurons responsive to whole body, periodic rotational stimulation in alert monkeys. This study characterizes the angular and linear motion-sensitive response properties of PBN unit responses during off-vertical axis rotation (OVAR) and position trapezoid stimulation. The OVAR responses displayed a constant firing component which varied from the firing rate at rest. Nearly two-thirds of the units also modulated their discharges with respect to head orientation (re: gravity) during constant velocity OVAR stimulation. The modulated response magnitudes were equal during ipsilateral and contralateral OVARs, indicative of a one-dimensional accelerometer. These response orientations during OVAR divided the units into three spatially tuned populations, with peak modulation responses centered in the ipsilateral ear down, contralateral anterior semicircular canal down, and occiput down orientations. Because the orientation of the OVAR modulation response was opposite in polarity to the orientation of the static tilt component of responses to position trapezoids for the majority of units, the linear acceleration responses were divided into colinear dynamic linear and static tilt components. The orientations of these unit responses formed two distinct population response axes: (1) units with an interaural linear response axis and (2) units with an ipsilateral anterior semicircular canal-contralateral posterior semicircular canal plane linear response axis. The angular rotation sensitivity of these units is in a head-vertical plane that either contains the linear acceleration response axis or is perpendicular to the linear acceleration axis. Hence, these units behave like head-based (‘strap-down’) inertial guidance sensors. Because the PBN contributes to sensory and interoceptive processing, it is suggested that vestibulo-recipient caudal PBN units may detect potentially dangerous anomalies in control of postural stability during locomotion. In particular, these signals may contribute to the range of affective and emotional responses that include panic associated with falling, malaise associated with motion sickness and mal-de-debarquement, and comorbid balance and anxiety disorders. PMID:20039027

Conflicting motion perspective simulating sinultaneous clockwise and counterclockwise rotation in depth.

PubMed

Hershberger, W A; Stewart, M R; Laughlin, N K

1976-05-01

Motion projections (pictures) simulating a horizontal array of vertical lines rotating in depth about its central vertical line were observed by 24 college students who rotated a crank handle in the direction of apparent rotation. All displays incorporated contradictory motion perspective: Whereas the perspective transformation in the vertical (y) dimension stimulated one direction of rotation, the transformation in the horizontal (x) dimension simulated the opposite direction. The amount of perspective in each dimension was varied independently of the other by varying the projection ratio used for each dimension. We used the same five ratios for each dimension, combining them factorially to generate the 25 displays. Analysis of variance of the duration of crank turning which agreed with y-axis information yielded main effects of both x and y projection ratios but no interaction, revealing that x- and y-axis motion perspectives mediate kinetic depth effects which are functionally independent.

Apparatus for encapsulating a photovoltaic module

DOEpatents

Albright, Scot P.; Dugan, Larry M.

1995-10-24

The subject inventions concern various photovoltaic module designs to protect the module from horizontal and vertical impacts and degradation of solar cell efficiency caused by moisture. In one design, a plurality of panel supports that are positioned adjacent to the upper panel in a photovoltaic module absorb vertical forces exerted along an axis perpendicular to the upper panel. Other designs employ layers of glass and tempered glass, respectively, to protect the module from vertical impacts. A plurality of button-shaped channels is used around the edges of the photovoltaic module to absorb forces applied to the module along an axis parallel to the module and direct moisture away from the module that could otherwise penetrate the module and adversely affect the cells within the module. A spacer is employed between the upper and lower panels that has a coefficient of thermal expansion substantially equivalent to the coefficient of thermal expansion of at least one of the panels.

Perceptual Simulation in Gender Categorization: Associations between Gender, Vertical Height, and Spatial Size

PubMed Central

Zhang, Xiaobin; Li, Qiong; Eskine, Kendall J.; Zuo, Bin

2014-01-01

The current studies extend perceptual symbol systems theory to the processing of gender categorization by revealing that gender categorization recruits perceptual simulations of spatial height and size dimensions. In study 1, categorization of male faces were faster when the faces were in the “up” (i.e., higher on the vertical axis) rather than the “down” (i.e., lower on the vertical axis) position and vice versa for female face categorization. Study 2 found that responses to male names depicted in larger font were faster than male names depicted in smaller font, whereas opposite response patterns were given for female names. Study 3 confirmed that the effect in Study 2 was not due to metaphoric relationships between gender and social power. Together, these findings suggest that representation of gender (social categorization) also involves processes of perceptual simulation. PMID:24587022

Coherent Structures and Extreme Events in Rotating Multiphase Turbulent Flows

NASA Astrophysics Data System (ADS)

Biferale, L.; Bonaccorso, F.; Mazzitelli, I. M.; van Hinsberg, M. A. T.; Lanotte, A. S.; Musacchio, S.; Perlekar, P.; Toschi, F.

2016-10-01

By using direct numerical simulations (DNS) at unprecedented resolution, we study turbulence under rotation in the presence of simultaneous direct and inverse cascades. The accumulation of energy at large scale leads to the formation of vertical coherent regions with high vorticity oriented along the rotation axis. By seeding the flow with millions of inertial particles, we quantify—for the first time—the effects of those coherent vertical structures on the preferential concentration of light and heavy particles. Furthermore, we quantitatively show that extreme fluctuations, leading to deviations from a normal-distributed statistics, result from the entangled interaction of the vertical structures with the turbulent background. Finally, we present the first-ever measurement of the relative importance between Stokes drag, Coriolis force, and centripetal force along the trajectories of inertial particles. We discover that vortical coherent structures lead to unexpected diffusion properties for heavy and light particles in the directions parallel and perpendicular to the rotation axis.

Paleomagnetic and Seismologic Evidence for Oblique-Slip Partitioning to the Coalinga Anticline From the San Andreas Fault

NASA Astrophysics Data System (ADS)

Tetreault, J. L.; Jones, C. H.

2007-12-01

The Coalinga Anticline is a one of a series of fault-related folds in the central Coast Ranges, California, oriented subparallel to the San Andreas Fault (SAF). The development of the Central Coast Range anticlines can be related to the relative strength of the SAF. If positing a weak SAF, fault-normal slip is partitioned to these subparallel compressional folds. If the SAF is strong, these folds rotated to their current orientation during wrenching. Another possibility is that the Coast Range anticlines are accommodating oblique-slip partitioned from the SAF. The 1983 Coalinga earthquake does not have a purely thrusting focal mechanism (rake =100°), reflecting the likelihood that oblique slip is being partitioned to this anticline, even though surface expression of fold-axis-parallel slip has not been identified. Paleomagnetic vertical-axis rotations and focal mechanism strain inversions were used to quantify oblique-slip deformation within the Coalinga Anticline. Clockwise rotations of 10° to 16° are inferred from paleomagnetic sites located in late Miocene to Pliocene beds on the steeply dipping forelimb and backlimb of the fold. Significant vertical-axis rotations are not identified in the paleomagnetic sites within the nose of the anticline. The varying vertical axis rotations conflict with wrench tectonics (strong SAF) as the mechanism of fold development. We use focal mechanisms inversions of earthquakes that occurred between 1983 to 2006 to constrain the seismogenic strain within the fold that presumably help to build it over time. In the upper 7 km, the principal shortening axis is oriented N37E to N40E, statistically indistinguishable from normal to the fold (N45E). The right-lateral shear in the folded strata above the fault tip, evident from the paleomagnetically determined clockwise vertical-axis rotations, is being accommodated aseismically or interseismically. In the region between 7 and 11 km, where the mainshock occurred, the shortening direction ranges from oblique to normal to the fold trend. Our results show that right-lateral slip is resolved along the main fault plane and not distributed to the smaller aftershocks at depths of 7-11 km. The principal strain axes and clockwise paleomagnetic rotations indicate that the Coalinga Anticline is accommodating minor right-lateral shearing and thus shares some of the strike-slip motion of the San Andreas system.

An efficient and economical way to enhance the performance of present HTS Maglev systems by utilizing the anisotropy property of bulk superconductors

NASA Astrophysics Data System (ADS)

Deng, Zigang; Wang, Jiasu; Zheng, Jun; Zhang, Ya; Wang, Suyu

2013-02-01

We report a simple, efficient and economical way to enhance the levitation or guidance performance of present high-temperature superconducting (HTS) Maglev systems by exploring the anisotropic properties of the critical current density in the a-b plane and along the c-axis of bulk superconductors. In the method, the bulk laying mode with different c-axis directions is designed to match with the magnetic field configuration of the applied permanent magnet guideway (PMG). Experimental results indicate that more than a factor of two improvement in the levitation force or guidance force is achieved when changing the laying mode of bulk superconductors from the traditional fashion of keeping the c-axis vertical to the PMG surface to the studied one of keeping the c-axis parallel to the PMG surface, at the maximum horizontal and vertical magnetic field positions of the PMG, respectively. These phenomena resulted from the physical nature of the generated levitation force and guidance force (electromagnetic forces) and the fact that there are different critical current densities in the a-b plane and along the c axis. Based on the experimental results, new HTS Maglev systems can be designed to meet the requirements of practical heavy-load or curved-route applications.

Whole-body vibration exposure study in U.S. railroad locomotives--an ergonomic risk assessment.

PubMed

Johanning, Eckardt; Fischer, Siegfried; Christ, Eberhard; Göres, Benno; Landsbergis, Paul

2002-01-01

Whole-body vibration exposure of locomotive engineers and the vibration attenuation of seats in 22 U.S. locomotives (built between 1959 and 2000) was studied during normal revenue service and following international measurement guidelines. Triaxial vibration measurements (duration mean 155 min, range 84-383 min) on the seat and on the floor were compared. In addition to the basic vibration evaluation (aw rms), the vector sum (av), the maximum transient vibration value (MTVV/aw), the vibration dose value (VDV/(aw T1/4)), and the vibration seat effective transmissibility factor (SEAT) were calculated. The power spectral densities are also reported. The mean basic vibration level (aw rms) was for the fore-aft axis x = 0.18 m/sec2, the lateral axis y = 0.28 m/sec2, and the vertical axis z = 0.32 m/sec2. The mean vector sum was 0.59 m/sec2 (range 0.27 to 1.44). The crest factors were generally at or above 9 in the horizontal and vertical axis. The mean MTVV/aw was 5.3 (x), 5.1 (y), and 4.8 (z), and the VDV/(aw T1/4) values ranged from 1.32 to 2.3 (x-axis), 1.33 to 1.7 (y-axis), and 1.38 to 1.86 (z-axis), generally indicating high levels of shocks. The mean seat transmissibility factor (SEAT) was 1.4 (x) and 1.2 (y) and 1 (z), demonstrating a general ineffectiveness of any of the seat suspension systems. In conclusion, these data indicate that locomotive rides are characterized by relatively high shock content (acceleration peaks) of the vibration signal in all directions. Locomotive vertical and lateral vibrations are similar, which appears to be characteristic for rail vehicles compared with many road/off-road vehicles. Tested locomotive cab seats currently in use (new or old) appear inadequate to reduce potentially harmful vibration and shocks transmitted to the seated operator, and older seats particularly lack basic ergonomic features regarding adjustability and postural support.

Starting to Explore Wind Power

ERIC Educational Resources Information Center

Hare, Jonathan

2008-01-01

Described is a simple, cheap and versatile homemade windmill and electrical generator suitable for a school class to use to explore many aspects and practicalities of using wind to generate electrical power. (Contains 8 figures.)

Contest Physics.

ERIC Educational Resources Information Center

Moehnke, Randy

1994-01-01

Discusses the use of contests to keep physics interesting and exciting for the students. Includes: balloon car, egg drop, tennis ball catapult, bridge building, mousetrap vehicle, musical instrument, slide photo, electric junk dissection, windmill generator, and solar heater. (MVL)

8. FLOOR 1: TENTERING GEAR FOR SOUTH STONES, CENTRIFUGAL GOVERNOR ...

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

8. FLOOR 1: TENTERING GEAR FOR SOUTH STONES, CENTRIFUGAL GOVERNOR MOUNTED ON STONE SPINDLE, VERY SHORT STEELYARD - Windmill at Water Mill, Montauk Highway & Halsey Lane, Water Mill, Suffolk County, NY

Polarization-independent transparent effect in windmill-like metasurface

NASA Astrophysics Data System (ADS)

Zhu, Lei; Dong, Liang; Guo, Jing; Meng, Fan Yi; He, Xun Jun; Hao Wu, Tian

2018-07-01

A windmill-like metasurface featuring a polarization-independent electromagnetically induced transparency (EIT) at microwave frequencies is numerically and experimentally demonstrated. The unit cell of the metasurface consists of four rotated identical metal wires, with a 45° angle between the adjacent wires. Destructive coupling between the resonance modes of the metal wires results in the emergence of a transparent window. By combining the metal wires with different degrees of symmetry, EIT effects in the metasurface show polarization-independent properties to incident linear and circular polarization waves. In addition, it is numerically demonstrated that the metasurface possesses a low-loss slow wave property with a group index of 125 and sensing capability based on the refractive index with a figure of merit of 8.73. Such a scheme may lead to many potential applications in areas of slow light and sensing.

Alternative Operational Energy Options - A Need for a Holistic Approach to Reduce the Logistics Tail and Improve Strategic Advantage

DTIC Science & Technology

2015-02-18

tends to resurge when the cost of petroleum rises as it did during the energy crisis of the 1970’s. Wind turbines are divided into two categories that...include horizontal axis and vertical axis. Horizontal-axis wind turbines have a main rotor driving an electrical generator on... turbines . They convert significantly more power in medium and higher winds than drag blades. Blades are attached directly to a hub just like on a

Gravitomagnetic Acceleration of Black Hole Accretion Disk Matter to Polar Jets

NASA Astrophysics Data System (ADS)

Poirier, John; Mathews, Grant

2015-04-01

It is shown that the motion of the neutral masses in an accretion disk orbiting a black hole creates a magnetic-like (gravitomagnetic) field that vertically accelerates neutral particles near the accretion disk away from the disk and then inward toward the axis of the accretion disk. Moreover, as the accelerated material nears the axis, a frame-dragging effect twists the trajectories around the axis thus contributing to the formation of a narrow polar jet emanating from the poles.

Retrieval of Vertical Aerosol and Trace Gas Distributions from Polarization Sensitive Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS)

NASA Astrophysics Data System (ADS)

Tirpitz, Jan-Lukas; Friess, Udo; Platt, Ulrich

2017-04-01

An accurate knowledge of the vertical distribution of trace gases and aerosols is crucial for our understanding of the chemical and dynamical processes in the lower troposphere. Their accurate determination is typically only possible by means of laborious and expensive airborne in-situ measurements but in the recent decades, numerous promising ground-based remote sensing approaches have been developed. One of them is to infer vertical distributions from "Differential Optical Absorption Spectroscopy" (DOAS) measurements. DOAS is a technique to analyze UV- and visible radiation spectra of direct or scattered sunlight, which delivers information on different atmospheric parameters, integrated over the light path from space to the instrument. An appropriate set of DOAS measurements, recorded under different viewing directions (Multi-Axis DOAS) and thus different light path geometries, provides information on the atmospheric state. The vertical profiles of aerosol properties and trace gas concentrations can be retrieved from such a set by numerical inversion techniques, incorporating radiative transfer models. The information content of measured data is rarely sufficient for a well-constrained retrieval, particularly for atmospheric layers above 1 km. We showed in first simulations that, apart from spectral properties, the polarization state of skylight is likely to provide a significant amount of additional information on the atmospheric state and thus to enhance retrieval quality. We present first simulations, expectations and ideas on how to implement and characterize a polarization sensitive Multi-Axis DOAS instrument and a corresponding profile retrieval algorithm.

THE EVOLUTION OF THE ELECTRIC CURRENT DURING THE FORMATION AND ERUPTION OF ACTIVE-REGION FILAMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jincheng; Yan, Xiaoli; Qu, Zhongquan

We present a comprehensive study of the electric current related to the formation and eruption of active region filaments in NOAA AR 11884. The vertical current on the solar surface was investigated by using vector magnetograms (VMs) observed by HMI on board the Solar Dynamics Observatory. To obtain the electric current along the filament's axis, we reconstructed the magnetic fields above the photosphere by using nonlinear force-free field extrapolation based on photospheric VMs. Spatio-temporal evolutions of the vertical current on the photospheric surface and the horizontal current along the filament's axis were studied during the long-term evolution and eruption-related period,more » respectively. The results show that the vertical currents of the entire active region behaved with a decreasing trend and the magnetic fields also kept decreasing during the long-term evolution. For the eruption-related evolution, the mean transverse field strengths decreased before two eruptions and increased sharply after two eruptions in the vicinity of the polarity inversion lines underneath the filament. The related vertical current showed different behaviors in two of the eruptions. On the other hand, a very interesting feature was found: opposite horizontal currents with respect to the current of the filament's axis appeared and increased under the filament before the eruptions and disappeared after the eruptions. We suggest that these opposite currents were carried by the new flux emerging from the photosphere bottom and might be the trigger mechanism for these filament eruptions.« less

14 CFR 25.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2012 CFR

2012-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 27.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2014 CFR

2014-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 27.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2013 CFR

2013-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 27.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2012 CFR

2012-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 29.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2012 CFR

2012-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 23.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2013 CFR

2013-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 25.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2011 CFR

2011-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 23.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2014 CFR

2014-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 25.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2013 CFR

2013-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 27.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2011 CFR

2011-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 29.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2011 CFR

2011-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 25.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2014 CFR

2014-01-01

... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 29.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2013 CFR

2013-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 23.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2012 CFR

2012-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 23.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2011 CFR

2011-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

14 CFR 29.1387 - Position light system dihedral angles.

Code of Federal Regulations, 2014 CFR

2014-01-01

... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

Microwave and Millimeter Wave Properties of Vertically-Aligned Single Wall Carbon Nanotubes Films

NASA Astrophysics Data System (ADS)

Haddadi, K.; Tripon-Canseliet, C.; Hivin, Q.; Ducournau, G.; Teo, E.; Coquet, P.; Tay, B. K.; Lepilliet, S.; Avramovic, V.; Chazelas, J.; Decoster, D.

2016-05-01

We present the experimental determination of the complex permittivity of vertically aligned single wall carbon nanotubes (SWCNTs) films grown on quartz substrates in the microwave regime from 10 MHz up to 67 GHz, with the electrical field perpendicular to the main axis of the carbon nanotubes (CNTs), based on coplanar waveguide transmission line approach together with the measurement of the microwave impedance of top metalized vertically—aligned SWCNTs grown on conductive silicon substrates up to 26 GHz. From coplanar waveguide measurements, we obtain a real part of the permittivity almost equal to unity, which is interpreted in terms of low carbon atom density (3 × 1019 at/cm3) associated with a very low imaginary part of permittivity (<10-3) in the frequency range considered due to a very small perpendicular conductivity. The microwave impedance of a vertically aligned CNTs bundle equivalent to a low resistance reveals a good conductivity (3 S/cm) parallel to the CNTs axis. From these two kinds of data, we experimentally demonstrate the tensor nature of the vertically grown CNTs bundles.

The Managerial Grid; Key Orientations for Achieving Production through People.

ERIC Educational Resources Information Center

Blake, Robert R; Mouton, Jane S.

The Managerial Grid arranges a concern for production on the horizontal axis and a concern for people on the vertical axis of a coordinate system: 1,1 shows minimum concern for production and people; 9,1 shows major production emphasis and minimum human considerations; 1,9 shows maximum concern for friendly working conditions and minimum…

Coding of Velocity Storage in the Vestibular Nuclei.

PubMed

Yakushin, Sergei B; Raphan, Theodore; Cohen, Bernard

2017-01-01

Semicircular canal afferents sense angular acceleration and output angular velocity with a short time constant of ≈4.5 s. This output is prolonged by a central integrative network, velocity storage that lengthens the time constants of eye velocity. This mechanism utilizes canal, otolith, and visual (optokinetic) information to align the axis of eye velocity toward the spatial vertical when head orientation is off-vertical axis. Previous studies indicated that vestibular-only (VO) and vestibular-pause-saccade (VPS) neurons located in the medial and superior vestibular nucleus could code all aspects of velocity storage. A recently developed technique enabled prolonged recording while animals were rotated and received optokinetic stimulation about a spatial vertical axis while upright, side-down, prone, and supine. Firing rates of 33 VO and 8 VPS neurons were studied in alert cynomolgus monkeys. Majority VO neurons were closely correlated with the horizontal component of velocity storage in head coordinates, regardless of head orientation in space. Approximately, half of all tested neurons (46%) code horizontal component of velocity in head coordinates, while the other half (54%) changed their firing rates as the head was oriented relative to the spatial vertical, coding the horizontal component of eye velocity in spatial coordinates. Some VO neurons only coded the cross-coupled pitch or roll components that move the axis of eye rotation toward the spatial vertical. Sixty-five percent of these VO and VPS neurons were more sensitive to rotation in one direction (predominantly contralateral), providing directional orientation for the subset of VO neurons on either side of the brainstem. This indicates that the three-dimensional velocity storage integrator is composed of directional subsets of neurons that are likely to be the bases for the spatial characteristics of velocity storage. Most VPS neurons ceased firing during drowsiness, but the firing rates of VO neurons were unaffected by states of alertness and declined with the time constant of velocity storage. Thus, the VO neurons are the prime components of the mechanism of coding for velocity storage, whereas the VPS neurons are likely to provide the path from the vestibular to the oculomotor system for the VO neurons.

Coding of Velocity Storage in the Vestibular Nuclei

PubMed Central

Yakushin, Sergei B.; Raphan, Theodore; Cohen, Bernard

2017-01-01

Semicircular canal afferents sense angular acceleration and output angular velocity with a short time constant of ≈4.5 s. This output is prolonged by a central integrative network, velocity storage that lengthens the time constants of eye velocity. This mechanism utilizes canal, otolith, and visual (optokinetic) information to align the axis of eye velocity toward the spatial vertical when head orientation is off-vertical axis. Previous studies indicated that vestibular-only (VO) and vestibular-pause-saccade (VPS) neurons located in the medial and superior vestibular nucleus could code all aspects of velocity storage. A recently developed technique enabled prolonged recording while animals were rotated and received optokinetic stimulation about a spatial vertical axis while upright, side-down, prone, and supine. Firing rates of 33 VO and 8 VPS neurons were studied in alert cynomolgus monkeys. Majority VO neurons were closely correlated with the horizontal component of velocity storage in head coordinates, regardless of head orientation in space. Approximately, half of all tested neurons (46%) code horizontal component of velocity in head coordinates, while the other half (54%) changed their firing rates as the head was oriented relative to the spatial vertical, coding the horizontal component of eye velocity in spatial coordinates. Some VO neurons only coded the cross-coupled pitch or roll components that move the axis of eye rotation toward the spatial vertical. Sixty-five percent of these VO and VPS neurons were more sensitive to rotation in one direction (predominantly contralateral), providing directional orientation for the subset of VO neurons on either side of the brainstem. This indicates that the three-dimensional velocity storage integrator is composed of directional subsets of neurons that are likely to be the bases for the spatial characteristics of velocity storage. Most VPS neurons ceased firing during drowsiness, but the firing rates of VO neurons were unaffected by states of alertness and declined with the time constant of velocity storage. Thus, the VO neurons are the prime components of the mechanism of coding for velocity storage, whereas the VPS neurons are likely to provide the path from the vestibular to the oculomotor system for the VO neurons. PMID:28861030

Apparatus for checking dimensions of workpieces

DOEpatents

Possati, Mario; Golinelli, Guido

1992-01-01

An apparatus for checking features of workpieces with rotational symmetry defining a geometrical axis, which includes a base, rest devices fixed to the base for supporting the workpiece with the geometrical axis horizontally arranged, and a support structure coupled to the base for rotation about a horizontal axis. A counterweight and sensor are coupled to the support structure and movable with the support structure from a rest position, allowing loading of the workpiece to be checked onto the rest devices to a working position where the sensor is brought into cooperation with the workpiece. The axis of rotation of the support structure is arranged below the axis of the workpiece, in correspondence to a vertical geometrical plane passing through the workpiece geometric axis when the workpiece is positioned on the rest devices.

13. FLOOR 1: DETAIL OF POSTS SUPPORTING BRIDGE TREE TO ...

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

13. FLOOR 1: DETAIL OF POSTS SUPPORTING BRIDGE TREE TO NORTH; NOTE BEADING AT CORNERS; WEDGES ADJUST HEIGHT OF PIVOTING END OF BRIDGE TREE - Pantigo Windmill, James Lane, East Hampton, Suffolk County, NY

A Conversation with the New Alchemists.

ERIC Educational Resources Information Center

Greene, Wade

1978-01-01

Reports on a visit to the New Alchemy Institute, a cluster of windmills and fish and vegetable production systems on a 12-acre site on Cape Cod. They are active in the appropriate technology movement. (BB)

9. FLOOR 1: FLOUR BOLTER, REEL IN PLACE BUT CLOTH ...

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

9. FLOOR 1: FLOUR BOLTER, REEL IN PLACE BUT CLOTH MISSING: LAYSHAFT WHICH FORMERLY DROVE BOLTER IS STORED AGAINST WALL - Windmill at Water Mill, Montauk Highway & Halsey Lane, Water Mill, Suffolk County, NY

3. HJELM FARMSTEAD. OVERVIEW SHOWING EDGE OF GRANARY, SMALL BARN, ...

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

3. HJELM FARMSTEAD. OVERVIEW SHOWING EDGE OF GRANARY, SMALL BARN, WINDMILL, AND POTATO CELLAR. VIEW TO SOUTH-SOUTHEAST. - Hjelm Farmstead, U.S. Highway 20 at New Sweden, Idaho Falls, Bonneville County, ID

Wind measurement system

NASA Technical Reports Server (NTRS)

Cliff, W. C.; Huffaker, R. M.; Dahm, W. K.; Thomson, J. A. L.; Lawrence, T. R.; Krause, M. C.; Wilson, D. J. (Inventor)

1976-01-01

A system for remotely measuring vertical and horizontal winds present in discrete volumes of air at selected locations above the ground is described. A laser beam is optically focused in range by a telescope, and the output beam is conically scanned at an angle about a vertical axis. The backscatter, or reflected light, from the ambient particulates in a volume of air, the focal volume, is detected for shifts in wavelength, and from these, horizontal and vertical wind components are computed.

Impact of NO2 horizontal heterogeneity on tropospheric NO2 vertical columns retrieved from satellite, multi-axis differential optical absorption spectroscopy, and in situ measurements

NASA Astrophysics Data System (ADS)

Mendolia, D.; D'Souza, R. J. C.; Evans, G. J.; Brook, J.

2013-01-01

Tropospheric NO2 vertical column densities were retrieved for the first time in Toronto, Canada using three methods of differing spatial scales. Remotely-sensed NO2 vertical column densities, retrieved from multi-axis differential optical absorption spectroscopy and satellite remote sensing, were evaluated by comparison with in situ vertical column densities derived using a pair of chemiluminescence monitors situated 0.01 and 0.5 km above ground level. The chemiluminescence measurements were corrected for the influence of NOz, which reduced the NO2 concentrations at 0.01 and 0.5 km by 8 ± 1% and 12 ± 1%, respectively. The average absolute decrease in the chemiluminescence NO2 measurement as a result of this correction was less than 1 ppb. Good correlation was observed between the remotely sensed and in situ NO2 vertical column densities (Pearson R ranging from 0.68 to 0.79), but the in situ vertical column densities were 27% to 55% greater than the remotely-sensed columns. These results indicate that NO2 horizontal heterogeneity strongly impacted the magnitude of the remotely-sensed columns. The in situ columns reflected an urban environment with major traffic sources, while the remotely-sensed NO2 vertical column densities were representative of the region, which included spatial heterogeneity introduced by residential neighbourhoods and Lake Ontario. Despite the difference in absolute values, the reasonable correlation between the vertical column densities determined by three distinct methods increased confidence in the validity of the values provided by each of the methods.

On the Behavior of Pliable Plate Dynamics in Wind: Application to Vertical Axis Wind Turbines

NASA Astrophysics Data System (ADS)

Cosse, Julia Theresa

Numerous studies have shown that flexible materials improve resilience and durability of a structure. Several studies have investigated the behavior of elastic plates under the influence of a free stream, such as studies of the fluttering flag and others of shape reconfiguration, due to a free stream. The principle engineering contribution of this thesis is the design and development of a vertical axis wind turbine that features pliable blades which undergo various modes of behavior, ultimately leading to rotational propulsion of the turbine. The wind turbine design was tested in a wind tunnel and at the Caltech Laboratory for Optimized Wind Energy. Ultimately, the flexible blade vertical axis wind turbine proved to be an effective way of harnessing the power of the wind. In addition, this body of work builds on the current knowledge of elastic cantilever plates in a free stream flow by investigating the inverted flag. While previous studies have focused on the fluid structure interaction of a free stream on elastic cantilever plates, none had studied the plate configuration where the trailing edge was clamped, leaving the leading edge free to move. Furthermore, the studies presented in this thesis establish the geometric boundaries of where the large-amplitude flapping occurs.

The effect of a multi-axis suspension on whole body vibration exposures and physical stress in the neck and low back in agricultural tractor applications.

PubMed

Kim, Jeong Ho; Dennerlein, Jack T; Johnson, Peter W

2018-04-01

Whole body vibration (WBV) exposures are often predominant in the fore-aft (x) or lateral (y) axis among off-road agricultural vehicles. However, as the current industry standard seats are designed to reduce mainly vertical (z) axis WBV exposures, they may be less effective in reducing drivers' exposure to multi-axial WBV. Therefore, this laboratory-based study aimed to determine the differences between a single-axial (vertical) and multi-axial (vertical + lateral) suspension seat in reducing WBV exposures, head acceleration, self-reported discomfort, and muscle activity (electromyography) of the major muscle of the low back, neck and shoulders. The results showed that the multi-axial suspension seat had significantly lower WBV exposures compared to the single-axial suspension seats (p' < 0.04). Similarly, the multi-axial suspension seat had lower head acceleration and muscle activity of the neck, shoulder, and low back compared to the single-axial suspension seat; some but not all of the differences were statistically significant. These results indicate that the multi-axial suspension seat may reduce the lateral WBV exposures and associated muscular loading in the neck and low back in agricultural vehicle operators. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative Assessment of Torso and Seat Mounted Restraint Systems using Manikins on the Vertical Deceleration Tower

DTIC Science & Technology

2017-03-01

experimental effort involving a series of +z-axis impact tests was conducted on the 711th Human Performance Wing’s Vertical Deceleration Tower (VDT...parameters) and a JSF-styled ejection seat configuration (combined non -baseline test parameters) produced similar biodynamic response parameters for the LOIS...Photography .............................................................................. 12 6.0 EXPERIMENTAL DESIGN

The effect of solidity on the performance of H-rotor Darrieus turbine

NASA Astrophysics Data System (ADS)

Hassan, S. M. Rakibul; Ali, Mohammad; Islam, Md. Quamrul

2016-07-01

Utilization of wind energy has been investigated for a long period of time by different researchers in different ways. Out of which, the Horizontal Axis Wind Turbine and the Vertical Axis Wind Turbine have now advanced design, but still there is scope to improve their efficiency. The Vertical Axis Wind Turbine (VAWT) has the advantage over Horizontal Axis Wind Turbine (HAWT) for working on omnidirectional air flow without any extra control system. A modified H-rotor Darrieus type VAWT is analysed in this paper, which is a lift based wind turbine. The effect of solidity (i.e. chord length, no. of blades) on power coefficient (CP) of H-rotor for different tip speed ratios is numerically investigated. The study is conducted using time dependent RANS equations using SST k-ω model. SIMPLE scheme is used as pressure-velocity coupling and in all cases, the second order upwind discretization scheme is chosen for getting more accurate solution. In results, different parameters are compared, which depict the performance of the modified H-rotor Darrieus type VAWT. Double layered H-rotor having inner layer blades with longer chord gives higher power coefficient than those have inner layer blades with smaller chord.

Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines

NASA Astrophysics Data System (ADS)

Mendoza, Victor; Bachant, Peter; Wosnik, Martin; Goude, Anders

2016-09-01

Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion.

Experimental determination of the navigation error of the 4-D navigation, guidance, and control systems on the NASA B-737 airplane

NASA Technical Reports Server (NTRS)

Knox, C. E.

1978-01-01

Navigation error data from these flights are presented in a format utilizing three independent axes - horizontal, vertical, and time. The navigation position estimate error term and the autopilot flight technical error term are combined to form the total navigation error in each axis. This method of error presentation allows comparisons to be made between other 2-, 3-, or 4-D navigation systems and allows experimental or theoretical determination of the navigation error terms. Position estimate error data are presented with the navigation system position estimate based on dual DME radio updates that are smoothed with inertial velocities, dual DME radio updates that are smoothed with true airspeed and magnetic heading, and inertial velocity updates only. The normal mode of navigation with dual DME updates that are smoothed with inertial velocities resulted in a mean error of 390 m with a standard deviation of 150 m in the horizontal axis; a mean error of 1.5 m low with a standard deviation of less than 11 m in the vertical axis; and a mean error as low as 252 m with a standard deviation of 123 m in the time axis.

Spherical Tippe Tops

NASA Astrophysics Data System (ADS)

Cross, Rod

2013-03-01

A tippe top (see Fig. 1) is usually constructed as a truncated sphere with a cylindrical peg on top, as indicated in Fig. 2(a). When spun rapidly on a horizontal surface, a tippe top spins about a vertical axis while rotating slowly about a horizontal axis until the peg touches the surface. At that point, weight is transferred to the peg, the truncated sphere rises off the surface, and the top spins on the peg until it is upright. A feature of a tippe top is that its center of mass, labeled G in Fig. 2, is below the geometric center of the sphere, C, when the top is at rest. That is where it will return if the top is tilted sideways and released since that is the stable equilibrium position. The fact that a tippe top turns upside down when it spins is therefore astonishing. The behavior of a tippe top is quite unlike that of a regular top since the spin axis remains closely vertical the whole time. The center of mass of a regular top can also rise, but the spin axis tilts upward as the top rises and enters a "sleeping" position.

Difference in quick phases induced by horizontal and vertical vestibular stimulations: role of the otolithic input.

PubMed

Pettorossi, V E; Errico, P; Ferraresi, A

1997-01-01

Quick phases (QPs) induced by horizontal and vertical sinusoidal vestibular stimulations were studied in rabbits, cats, and humans. In all the animals, large and frequent horizontal QPs were observed following yaw stimulation in prone position. By contrast, QPs were almost absent during roll stimulation in rabbits, and they were small and oblique during pitch stimulation in cats and humans. As a result of these differences, the range of gaze displacement induced by vestibular stimulations was greater in the horizontal plane than in the vertical one. We also found that the trajectory of the QPs in rabbits was kept horizontal even when the yaw rotation was off vertical axis of +/- 45 degrees in the sagittal plane. Moreover, in the rabbit, the rare horizontal QPs induced by roll stimulation did not change their orientation at various pitch angles of roll stimulation axis. The QPs were also analyzed following roll stimulation of the rabbit in supine position. In this condition, in which the otolithic receptors were activated in the opposite way compared to prone position, large vertical QPs were elicited. We concluded that these results provide evidence that the otolithic signal plays a role in controlling occurrence and trajectory orientation of the QPs.

Long range laser traversing system

NASA Technical Reports Server (NTRS)

Caudill, L. O. (Inventor)

1974-01-01

The relative azimuth bearing between first and second spaced terrestrial points which may be obscured from each other by intervening terrain is measured by placing at one of the points a laser source for projecting a collimated beam upwardly in the vertical plane. The collimated laser beam is detected at the second point by positioning the optical axis of a receiving instrument for the laser beam in such a manner that the beam intercepts the optical axis. In response to the optical axis intercepting the beam, the beam is deflected into two different ray paths by a beam splitter having an apex located on the optical axis. The energy in the ray paths is detected by separate photoresponsive elements that drive logic networks for proving indications of: (1) the optical axis intercepting the beam; (2) the beam being on the left of the optical axis and (3) the beam being on the right side of the optical axis.

Tectonic and kinematics of curved orogenic systems: insights from AMS analysis and paleomagnetism

NASA Astrophysics Data System (ADS)

Cifelli, Francesca; Mattei, Massimo

2016-04-01

During the past few years, paleomagnetism has been considered a unique tool for constraining kinematic models of curved orogenic systems, because of its great potential in quantifying vertical axis rotations and in discriminating between primary and secondary (orocline s.l.) arcs. In fact, based on the spatio-temporal relationships between deformation and vertical axis rotation, curved orogens can be subdivided as primary or secondary (oroclines s.l.), if they formed respectively in a self-similar manner without undergoing important variations in their original curved shape or if their curvature in map-view is the result of a bending about a vertical axis of rotation. In addition to the kinematics of the arc and the timing of its curvature, a crucial factor for understanding the origin of belts curvature is the knowledge of the geodynamic process governing arc formation. In this context, the detailed reconstruction of the rotational history is mainly based on paleomagnetic and structural analyses (fold axes, kinematic indicators), which include the magnetic fabric. In fact, in curved fold and thrust belts, assuming that the magnetic lineation is tectonically originated and formed during layer-parallel shortening (LPS) before vertical axis rotations, the orientation of the magnetic lineation often strictly follows the curvature of the orogeny. This assumption represents a fundamental prerequisite to fully understand the origin of orogenic arcs and to unravel the geodynamic processes responsible for their curvature. We present two case studies: the central Mediterranean arcs and the Alborz Mts in Iran. The Mediterranean area has represented an attractive region to apply paleomagnetic analysis, as it shows a large number of narrow arcs, whose present-day shape has been driven by the space-time evolution of the Mediterranean subduction system, which define a irregular and rather diffuse plate boundary. The Alborz Mts. form a sinuous range over 1,200 km long, defining from west to east a salient with a southward concavity which results in the wrapping of the South Caspian basin to the north, and a southward reentrant with apex which encircles the Central Iranian block to the south. The integration of paleomagnetic and AMS data indicates that this orogen started to form as an almost straight E-W oriented range and acquired its present-day curved shape by means of opposite vertical axis rotations. Such a process was probably caused by the relative motion between different rigid blocks (South Caspian, Central Iran, and the Eastern Iranian Blocks) forming the collision zone and hence must be a crustal to lithospheric-scale process.

Changes in Central Walker Lane Strain Accommodation near Bridgeport, California; as told by the Stanislaus Group

NASA Astrophysics Data System (ADS)

Carlson, C. W.; Pluhar, C. J.; Glen, J. M.; Farner, M. J.

2012-12-01

Accommodating ~20-25% of the dextral-motion between the Pacific and North American plates the Walker Lane is represented as an elongate, NW oriented, region of active tectonics positioned between the northwesterly-translating Sierra Nevada microplate and the east-west extension of the Basin and Range. This region of transtension is being variably accommodated on regional-scale systems of predominantly strike-slip faulting. At the western edge of the central Walker Lane (ca. 38°-39°N latitude) is a region of crustal-scale blocks bounded by wedge-shaped depositional-basins and normal-fault systems, here defined as the west-central Walker Lane (WCWL). Devoid of obvious strike-slip faulting, the presence of tectonic-block vertical-axis rotations in the WCWL represents unrecognized components of dextral-shearing and/or changes of strain-accommodation over time. We use paleomagnetic reference directions for Eureka Valley Tuff (EVT) members of the late Miocene Stanislaus Group as spatial and temporal markers for documentation of tectonic-block vertical-axis rotations near Bridgeport, CA. Study-site rotations revealed discrete rotational domains of mean vertical-axis rotation ranging from ~10°-30° with heterogeneous regional distribution. Additionally, the highest measured magnitudes of vertical-axis rotation (~50°-60° CW) define a 'Region of High Strain' that includes the wedge-shaped Bridgeport Valley (Basin). This study revealed previously-unrecognized tectonic rotation of reference direction sites from prior studies for two (By-Day and Upper) of the three members of the EVT, resulting in under-estimates of regional strain accommodation by these studies. Mean remanent directions and virtual geomagnetic poles utilized in our study yielded a recalculated reference direction for the By-Day member of: Dec.=353.2°; Inc.= 43.7°; α95=10.1, in agreement with new measurements in the stable Sierra Nevada. This recalculated direction confirmed the presence of previously unrecognized reference site rotations, and provided an additional reference direction for determining vertical-axis rotation magnitudes. We present a kinematic model based on mean rotation magnitudes of ~30° CW for the Sweetwater Mountains and Bodie Hills that accounts for rotational-strain accommodation of dextral shear in the WCWL since the late Miocene. This model considers rotational magnitudes, paleostrain indicators, edge-effects, and strain-accommodating structures of rotating crustal blocks to represent changes in regional strain accommodation over time. The results and models presented here elucidate the complicated and evolving nature of the WCWL, and further understanding of variations in strain accommodation for the Walker Lane.

Counter-rotating vortex pairs in the wake of a vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Rolin, Vincent; Porté-Agel, Fernando

2017-04-01

Despite the rising popularity of vertical axis wind turbines, or VAWTs, the wakes behind these machines is much less well understood than those behind horizontal axis wind turbines, or HAWTs. A thorough understanding of wakes is important as they can cause turbines in wind farms to produce less power than anticipated and increase the fatigue loading on turbines due to vibrations. In order to gain a deeper understanding of the wake behind a vertical axis wind turbine in atmospheric flow stereo-PIV is implemented in a boundary-layer wind tunnel to produce snapshots of the 3-component velocity field in the wake at various downstream positions. The boundaries of the wake are readily observed due to the high velocity gradients and turbulence present here. Two pairs of counter-rotating vortices similar to those in the wake of yawed HAWTs are also observed. An examination of the momentum fluxes behind the turbine demonstrates that the mean flow induced by these vortices entrains a large quantity of momentum from the unperturbed boundary layer flow above the wake. This effect proves to play an even more significant role than turbulence in reintroducing momentum into the wake. In order to comprehend why the VAWT produces these vortices we modify the double-multiple stream-tube model typically used to predict VAWT performance to incorporate crosswind forces. The similarity between VAWT and yawed HAWT wakes is found not to be coincidental as both cases feature rotors which exert a lateral thrust on the incoming wind which leads to the creation of counter-rotating vortex pairs.

Ocular Reflex Phase During Off-Vertical Axis Rotation In Humans Is Modified By Head-On-Trunk Position

NASA Technical Reports Server (NTRS)

Wood, Scott; Clement, Gilles; Denise, Pierre; Reschke, Millard

2005-01-01

Constant velocity Off-Vertical Axis Rotation (OVAR) imposes a continuously varying orientation of the head and body relative to gravity. The ensuing ocular reflexes include modulation of both horizontal and torsional eye velocity as a function of the varying linear acceleration along the lateral plane. The purpose of this study was to examine whether the modulation of these ocular reflexes would be modified by different head-on-trunk positions. Ten human subjects were rotated in darkness about their longitudinal axis 20 deg off-vertical at constant rates of 45 and 180 deg/s, corresponding to 0.125 and 0.5 Hz. Binocular responses were obtained with video-oculography with the head and trunk aligned, and then with the head turned relative to the trunk 40 deg to the right or left of center. Sinusoidal curve fits were used to derive amplitude, phase and bias velocity of the eye movements across multiple cycles for each head-on-trunk position. Consistent with previous studies, the modulation of torsional eye movements was greater at 0.125 Hz while the modulation of horizontal eye movements was greater at 0.5 Hz. Neither amplitude nor bias velocities were significantly altered by head-on-trunk position. The phases of both torsional and horizontal ocular reflexes, on the other hand, shifted towards alignment with the head. These results are consistent with the modulation of torsional and horizontal ocular reflexes during OVAR being primarily mediated by the otoliths in response to the sinusoidally varying linear acceleration along the interaural head axis.

Convective Sedimentation of Colloidal Particles in a Bowl.

PubMed

Stiles; Kagan

1999-08-01

A physical model, which regards a colloidal dispersion as a single fluid continuum, is used to investigate cellular convection accompanying gravitational sedimentation in a hemispherical bowl with a thin cylindrical shaft along its vertical axis of symmetry. We have adapted the stream-function-vorticity form of the Navier-Stokes equations to describe momentum conservation in axially symmetric containers. These hydrodynamic equations have been coupled to the mass balance equation for binary hydrodynamic diffusion in the presence of a vertical gravitational field. Using finite-element software we have solved the equations governing coupled diffusive and hydrodynamic flow. A rapidly intensifying horizontal toroidal vortex develops around the axis of the bowl. This vortex is characterized by downward barycentric flow along the curved surface of the bowl and upward flow in the vicinity of its axis. We find that after a short period of time this large-scale cellular convection associated with the curved boundary of the bowl greatly enhances the rate of sedimentation. Copyright 1999 Academic Press.

Plasticity of the human otolith-ocular reflex

NASA Technical Reports Server (NTRS)

Wall, C. 3rd; Smith, T. R.; Furman, J. M.

1992-01-01

The eye movement response to earth vertical axis rotation in the dark, a semicircular canal stimulus, can be altered by prior exposure to combined visual-vestibular stimuli. Such plasticity of the vestibulo-ocular reflex has not been described for earth horizontal axis rotation, a dynamic otolith stimulus. Twenty normal human subjects underwent one of two types of adaptation paradigms designed either to attenuate or enhance the gain of the semicircular canal-ocular reflex prior to undergoing otolith-ocular reflex testing with horizontal axis rotation. The adaptation paradigm paired a 0.2 Hz sinusoidal rotation about a vertical axis with a 0.2 Hz optokinetic stripe pattern that was deliberately mismatched in peak velocity. Pre- and post-adaptation horizontal axis rotations were at 60 degrees/s in the dark and produced a modulation in the slow component velocity of nystagmus having a frequency of 0.17 Hz due to putative stimulation of the otolith organs. Results showed that the magnitude of this modulation component response was altered in a manner similar to the alteration in semicircular canal-ocular responses. These results suggest that physiologic alteration of the vestibulo-ocular reflex using deliberately mismatched visual and semicircular canal stimuli induces changes in both canal-ocular and otolith-ocular responses. We postulate, therefore, that central nervous system pathways responsible for controlling the gains of canal-ocular and otolith-ocular reflexes are shared.

Theoretical axial wall angulation for rotational resistance form in an experimental-fixed partial denture

PubMed Central

2017-01-01

PURPOSE The aim of this study was to determine the influence of long base lengths of a fixed partial denture (FPD) to rotational resistance with variation of vertical wall angulation. MATERIALS AND METHODS Trigonometric calculations were done to determine the maximum wall angle needed to resist rotational displacement of an experimental-FPD model in 2-dimensional plane. The maximum wall angle calculation determines the greatest taper that resists rotation. Two different axes of rotation were used to test this model with five vertical abutment heights of 3-, 3.5-, 4-, 4.5-, and 5-mm. The two rotational axes were located on the mesial-side of the anterior abutment and the distal-side of the posterior abutment. Rotation of the FPD around the anterior axis was counter-clockwise, Posterior-Anterior (P-A) and clockwise, Anterior-Posterior (A-P) around the distal axis in the sagittal plane. RESULTS Low levels of vertical wall taper, ≤ 10-degrees, were needed to resist rotational displacement in all wall height categories; 2–to–6–degrees is generally considered ideal, with 7–to–10–degrees as favorable to the long axis of the abutment. Rotation around both axes demonstrated that two axial walls of the FPD resisted rotational displacement in each direction. In addition, uneven abutment height combinations required the lowest wall angulations to achieve resistance in this study. CONCLUSION The vertical height and angulation of FPD abutments, two rotational axes, and the long base lengths all play a role in FPD resistance form. PMID:28874995

Use of a magnetic force exciter to vibrate a piezocomposite generating element in a small-scale windmill

NASA Astrophysics Data System (ADS)

Truyen Luong, Hung; Goo, Nam Seo

2012-02-01

A piezocomposite generating element (PCGE) can be used to convert ambient vibrations into electrical energy that can be stored and used to power other devices. This paper introduces a design of a magnetic force exciter for a small-scale windmill that vibrates a PCGE to convert wind energy into electrical energy. A small-scale windmill was designed to be sensitive to low-speed wind in urban regions for the purpose of collecting wind energy. The magnetic force exciter consists of exciting magnets attached to the device’s input rotor and a secondary magnet fixed at the tip of the PCGE. The PCGE is fixed to a clamp that can be adjusted to slide on the windmill’s frame in order to change the gap between exciting and secondary magnets. Under an applied wind force, the input rotor rotates to create a magnetic force interaction that excites the PCGE. The deformation of the PCGE enables it to generate electric power. Experiments were performed with different numbers of exciting magnets and different gaps between the exciting and secondary magnets to determine the optimal configuration for generating the peak voltage and harvesting the maximum wind energy for the same range of wind speeds. In a battery-charging test, the charging time for a 40 mA h battery was approximately 3 h for natural wind in an urban region. The experimental results show that the prototype can harvest energy in urban regions with low wind speeds and convert the wasted wind energy into electricity for city use.

Vertical axis wind rotors: Status and potential. [energy conversion efficiency and aerodynamic characteristics

NASA Technical Reports Server (NTRS)

Vance, W.

1973-01-01

The design and application of a vertical axis wind rotor is reported that operates as a two stage turbine wherein the wind impinging on the concave side is circulated through the center of the rotor to the back of the convex side, thus decreasing what might otherwise be a high negative pressure region. Successful applications of this wind rotor to water pumps, ship propulsion, and building ventilators are reported. Also shown is the feasibility of using the energy in ocean waves to drive the rotor. An analysis of the impact of rotor aspect ratio on rotor acceleration shows that the amount of venting between rotor vanes has a very significant effect on rotor speed for a given wind speed.

Three-dimensional organization of vestibular related eye movements to rotational motion in pigeons

NASA Technical Reports Server (NTRS)

Dickman, J. D.; Beyer, M.; Hess, B. J.

2000-01-01

During rotational motions, compensatory eye movement adjustments must continually occur in order to maintain objects of visual interest as stable images on the retina. In the present study, the three-dimensional organization of the vestibulo-ocular reflex in pigeons was quantitatively examined. Rotations about different head axes produced horizontal, vertical, and torsional eye movements, whose component magnitude was dependent upon the cosine of the stimulus axis relative to the animal's visual axis. Thus, the three-dimensional organization of the VOR in pigeons appears to be compensatory for any direction of head rotation. Frequency responses of the horizontal, vertical, and torsional slow phase components exhibited high pass filter properties with dominant time constants of approximately 3 s.

The Department of Energy (DOE) research program in structural analysis of vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Sullivan, W. N.

The Darrieus-type Vertical Axis Wind Turbine (VAWT) presents a variety of unusual structural problems to designers. The level of understanding of these structural problems governs, to a large degree, the success or failure of today's rotor designs. A survey is presented of the technology available for rotor structural design with emphasis on the DOE research program now underway. Itemizations are included of the major structural issues unique to the VAWT along with discussion of available analysis techniques for each problem area. It is concluded that tools are available to at least approximately address the most important problems. However, experimental data for confirmation is rather limited in terms of volume and the range of rotor configurations tested.

Aeroelastic equations of motion of a Darrieus vertical-axis wind-turbine blade

NASA Technical Reports Server (NTRS)

Kaza, K. R. V.; Kvaternik, R. G.

1979-01-01

The second-degree nonlinear aeroelastic equations of motion for a slender, flexible, nonuniform, Darrieus vertical-axis wind turbine blade which is undergoing combined flatwise bending, edgewise bending, torsion, and extension are developed using Hamilton's principle. The blade aerodynamic loading is obtained from strip theory based on a quasi-steady approximation of two-dimensional incompressible unsteady airfoil theory. The derivation of the equations has its basis in the geometric nonlinear theory of elasticity and the resulting equations are consistent with the small deformation approximation in which the elongations and shears are negligible compared to unity. These equations are suitable for studying vibrations, static and dynamic aeroelastic instabilities, and dynamic response. Several possible methods of solution of the equations, which have periodic coefficients, are discussed.

Five-Axis, Three-Magnetic-Bearing Dynamic Spin Rig

NASA Technical Reports Server (NTRS)

Morrison, Carlos R.; Provenza, Andrew; Kurkov, Anatole; Mehmed, Oral; Johnson, Dexter; Montague, Gerald; Duffy, Kirsten; Jansen, Ralph

2005-01-01

The Five-Axis, Three-Magnetic-Bearing Dynamic Spin Rig is an apparatus for vibration testing of turbomachine blades in a vacuum at rotational speeds from 0 to 40,000 rpm. This rig includes (1) a vertically oriented shaft on which is mounted an assembly comprising a rotor holding the blades to be tested, (2) two actively controlled heteropolar radial magnetic bearings at opposite ends of the shaft, and (3) an actively controlled magnetic thrust bearing at the upper end of the shaft. This rig is a more capable successor to a prior apparatus, denoted the Dynamic Spin Rig (DSR), that included a vertically oriented shaft with a mechanical thrust bearing at the upper end and a single actively controlled heteropolar radial magnetic bearing at the lower end.

OPTICAL TRANSCRIBING OSCILLOSCOPE

DOEpatents

Kerns, Q.A.

1961-09-26

A device is designed for producing accurate graphed waveforms of very fast electronic pulses. The fast pulse is slowly tracked on a cathode ray tube and a pair of photomultiplier tubes, exposed to the pulse trace, view separate vertical portions thereof at each side of a fixed horizontal reference. Each phototube produces an output signal indicative of vertical movement of the exposed trace, which simultaneous signals are compared in a difference amplifier. The amplifier produces a difference signal which, when applied to the cathode ray tube, maintains the trace on the reference. A graphic recorder receives the amplified difference signal at an x-axis input, while a y-axis input is synchronized with the tracking time of the cathode ray tube and therefore graphs the enlarged waveshape.

An investigation into the vertical axis control power requirements for landing VTOL type aircraft onboard nonaviation ships in various sea states

NASA Technical Reports Server (NTRS)

Stevens, M. E.; Roskam, J.

1985-01-01

The problem of determining the vertical axis control requirements for landing a VTOL aircraft on a moving ship deck in various sea states is examined. Both a fixed-base piloted simulation and a nonpiloted simulation were used to determine the landing performance as influenced by thrust-to-weight ratio, vertical damping, and engine lags. The piloted simulation was run using a fixed-based simulator at Ames Research center. Simplified versions of an existing AV-8A Harrier model and an existing head-up display format were used. The ship model used was that of a DD963 class destroyer. Simplified linear models of the pilot, aircraft, ship motion, and ship air-wake turbulence were developed for the nonpiloted simulation. A unique aspect of the nonpiloted simulation was the development of a model of the piloting strategy used for shipboard landing. This model was refined during the piloted simulation until it provided a reasonably good representation of observed pilot behavior.

Accuracy of saccades to remembered targets as a function of body orientation in space

NASA Technical Reports Server (NTRS)

Vogelstein, Joshua T.; Snyder, Lawrence H.; Angelaki, Dora E.

2003-01-01

A vertical asymmetry in memory-guided saccadic eye movements has been previously demonstrated in humans and in rhesus monkeys. In the upright orientation, saccades generally land several degrees above the target. The origin of this asymmetry has remained unknown. In this study, we investigated whether the asymmetry in memory saccades is dependent on body orientation in space. Thus animals performed memory saccades in four different body orientations: upright, left-side-down (LSD), right-side-down (RSD), and supine. Data in all three rhesus monkeys confirm previous observations regarding a significant upward vertical asymmetry. Saccade errors made from LSD and RSD postures were partitioned into components made along the axis of gravity and along the vertical body axis. Up/down asymmetry persisted only in body coordinates but not in gravity coordinates. However, this asymmetry was generally reduced in tilted positions. Therefore the upward bias seen in memory saccades is egocentric although orientation in space might play a modulatory role.

A low-voltage three-axis electromagnetically actuated micromirror for fine alignment among optical devices

NASA Astrophysics Data System (ADS)

Cho, Il-Joo; Yoon, Euisik

2009-08-01

In this paper, a new three-axis electromagnetically actuated micromirror structure has been proposed and fabricated. It is electromagnetically actuated at low voltage using an external magnetic field. The main purpose of this work was to obtain a three-axis actuated micromirror in a mechanically robust structure with large static angular and vertical displacement at low actuation voltage for fine alignment among optical components in an active alignment module as well as conventional optical systems. The mirror plate and torsion bars are made of bulk silicon using a SOI wafer, and the actuation coils are made of electroplated Au. The maximum static deflection angles were measured as ±4.2° for x-axis actuation and ±9.2° for y-axis actuation, respectively. The maximum static vertical displacement was measured as ±42 µm for z-axis actuation. The actuation voltages were below 3 V for all actuation. The simulated resonant frequencies are several kHz, and these imply that the fabricated micromirror can be operated in sub-millisecond order. The measured radius of curvature (ROC) of the fabricated micromirror is 7.72 cm, and the surface roughness of the reflector is below 1.29 nm which ensure high optical performance such as high directionality and reflectivity. The fabricated micromirror has demonstrated large actuated displacement at low actuation voltage, and it enables us to compensate a larger misalignment value when it is used in an active alignment module. The robust torsion bar and lifting bar structure formed by bulk silicon allowed the proposed micromirror to have greater operating stability. The additional degree of freedom with z-axis actuation can decrease the difficulty in the assembly of optical components and increase the coupling efficiency between optical components.

10. FLOOR 1; CENTER POST AND POSTS UNDER STONE BEAMS ...

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

10. FLOOR 1; CENTER POST AND POSTS UNDER STONE BEAMS WHICH SUPPORT BRIDGE BEAMS FOR BRIDGE TREES; WEDGES FOR ADJUSTING HEIGHT OF BRIDGE TREE CAN BE SEEN - Shelter Island Windmill, Manwaring Road, Shelter Island, Suffolk County, NY

Offshore Wind Energy Systems

ERIC Educational Resources Information Center

Musgrove, P.

1978-01-01

Explores the possibility of installing offshore windmills to provide electricity and to save fuel for the United Kingdom. Favors their deployment in clusters to facilitate supervision and minimize cost. Discusses the power output and the cost involved and urges their quick development. (GA)

Pulling a Door Open by Pushing on It

ERIC Educational Resources Information Center

van den Berg, Willem H.

2007-01-01

Ordinarily, opening a door by pulling on the knob or handle causes a net torque on the door, and hence an angular acceleration, about a "vertical" axis. However, it may be that the top or bottom of the door sticks to the door frame; this horizontal force perpendicular to the plane of the door causes a torque on the door about a "horizontal" axis.…

Nonlinear dual-axis biodynamic response of the semi-supine human body during vertical whole-body vibration

NASA Astrophysics Data System (ADS)

Huang, Ya; Griffin, Michael J.

2008-04-01

Nonlinear biodynamic responses are evident in many studies of the apparent masses of sitting and standing subjects in static postures that require muscle activity for postural control. In the present study, 12 male subjects adopted a relaxed semi-supine posture assumed to involve less muscle activity than during static sitting and standing. The supine subjects were exposed to two types of vertical vibration (in the x-axis of the semi-supine body): (i) continuous random vibration (0.25-20 Hz) at five magnitudes (0.125, 0.25, 0.5, 0.75, and 1.0 m s -2 rms); (ii) intermittent random vibration (0.25-20 Hz) alternately at 0.25 and 1.0 m s -2 rms. With continuous random vibration, the dominant primary resonance frequency in the median normalised apparent mass decreased from 10.35 to 7.32 Hz as the vibration magnitude increased from 0.125 to 1.0 m s -2 rms. This nonlinear response was apparent in both the vertical ( x-axis) apparent mass and in the horizontal ( z-axis) cross-axis apparent mass. As the vibration magnitude increased from 0.25 to 1.0 m s -2 rms, the median resonance frequency of the apparent mass with intermittent random vibration decreased from 9.28 to 8.06 Hz whereas, over the same range of magnitudes with continuous random vibration, the resonance frequency decreased from 9.62 to 7.81 Hz. The median change in the resonance frequency (between 0.25 and 1.0 m s -2 rms) was 1.37 Hz with the intermittent random vibration and 1.71 with the continuous random vibration. With the intermittent vibration, the resonance frequency was higher at the high magnitude and lower at the low magnitude than with continuous vibration of the same magnitudes. The response was typical of thixotropy that may be a primary cause of the nonlinear biodynamic responses to whole-body vibration.

Dynamics of a spherical tippe top

NASA Astrophysics Data System (ADS)

Cross, Rod

2018-05-01

Experimental and theoretical results are presented concerning the inversion of a spherical tippe top. It was found that the top rises quickly while it is sliding and then more slowly when it starts rolling, in a manner similar to that observed previously with a spinning egg. As the top rises it rotates about the horizontal Y axis, an effect that is closely analogous to rotation of the top about the vertical Z axis. Both effects can be described in terms of precession about the respective axes. Steady precession about the Z axis arises from the normal reaction force in the Z direction, while precession about the Y axis arises from the friction force in the Y direction.

Visual guidance of forward flight in hummingbirds reveals control based on image features instead of pattern velocity.

PubMed

Dakin, Roslyn; Fellows, Tyee K; Altshuler, Douglas L

2016-08-02

Information about self-motion and obstacles in the environment is encoded by optic flow, the movement of images on the eye. Decades of research have revealed that flying insects control speed, altitude, and trajectory by a simple strategy of maintaining or balancing the translational velocity of images on the eyes, known as pattern velocity. It has been proposed that birds may use a similar algorithm but this hypothesis has not been tested directly. We examined the influence of pattern velocity on avian flight by manipulating the motion of patterns on the walls of a tunnel traversed by Anna's hummingbirds. Contrary to prediction, we found that lateral course control is not based on regulating nasal-to-temporal pattern velocity. Instead, birds closely monitored feature height in the vertical axis, and steered away from taller features even in the absence of nasal-to-temporal pattern velocity cues. For vertical course control, we observed that birds adjusted their flight altitude in response to upward motion of the horizontal plane, which simulates vertical descent. Collectively, our results suggest that birds avoid collisions using visual cues in the vertical axis. Specifically, we propose that birds monitor the vertical extent of features in the lateral visual field to assess distances to the side, and vertical pattern velocity to avoid collisions with the ground. These distinct strategies may derive from greater need to avoid collisions in birds, compared with small insects.

17. FLOOR l; DETAIL OF FRAMING; CANT POST HAS A ...

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

17. FLOOR l; DETAIL OF FRAMING; CANT POST HAS A SHOULDER FOR TIE BEAM WHICH SUPPORTS STONE BEAMS; BELOW TIE BEAM IS HINGE FOR THE BRAYER - Hook Windmill, North Main Street at Pantigo Road, East Hampton, Suffolk County, NY

Numerical and experimental study of the 3D effect on connecting arm of vertical axis tidal current turbine

NASA Astrophysics Data System (ADS)

Guo, Wei; Kang, Hai-gui; Chen, Bing; Xie, Yu; Wang, Yin

2016-03-01

Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF (User Defined Function) command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.

Cerebellar cathodal tDCS interferes with recalibration and spatial realignment during prism adaptation procedure in healthy subjects.

PubMed

Panico, Francesco; Sagliano, Laura; Grossi, Dario; Trojano, Luigi

2016-06-01

The aim of this study is to clarify the specific role of the cerebellum during prism adaptation procedure (PAP), considering its involvement in early prism exposure (i.e., in the recalibration process) and in post-exposure phase (i.e., in the after-effect, related to spatial realignment). For this purpose we interfered with cerebellar activity by means of cathodal transcranial direct current stimulation (tDCS), while young healthy individuals were asked to perform a pointing task on a touch screen before, during and after wearing base-left prism glasses. The distance from the target dot in each trial (in terms of pixels) on horizontal and vertical axes was recorded and served as an index of accuracy. Results on horizontal axis, that was shifted by prism glasses, revealed that participants who received cathodal stimulation showed increased rightward deviation from the actual position of the target while wearing prisms and a larger leftward deviation from the target after prisms removal. Results on vertical axis, in which no shift was induced, revealed a general trend in the two groups to improve accuracy through the different phases of the task, and a trend, more visible in cathodal stimulated participants, to worsen accuracy from the first to the last movements in each phase. Data on horizontal axis allow to confirm that the cerebellum is involved in all stages of PAP, contributing to early strategic recalibration process, as well as to spatial realignment. On vertical axis, the improving performance across the different stages of the task and the worsening accuracy within each task phase can be ascribed, respectively, to a learning process and to the task-related fatigue. Copyright © 2016 Elsevier Inc. All rights reserved.

Chemical Evidence for Vertical Transport from Magma Chambers to the Surface During Mid-Ocean Ridge Volcanic Eruptions

NASA Astrophysics Data System (ADS)

Sinton, J. M.; Rubin, K. H.

2009-12-01

Many mid-ocean ridge eruptions show significant internal chemical heterogeneity; in general, the amount of chemical heterogeneity within eruptions scales with erupted volume. These variations reflect magmatic processes occurring in magma reservoirs prior to or possibly during eruption. For example, systematic variations in Mg# with along-axis distance in the early 90’s Aldo-Kihi (S. EPR near 17.5°S), 1996 N. Gorda, 1993 Co-Axial (Juan de Fuca Ridge), and 1991-2 and 2005-6 9°50’N EPR eruptions is unlikely to be related to fractionation during emplacement, and rather reflects variations in sub-axial magma reservoirs prior to eruption. Such variations are inconsistent with well-mixed sub-axial reservoirs and, in some cases, require relatively long-lived, systematic variations in reservoir temperatures along axis. Chemical heterogeneity within the Aldo-Kihi eruption preserves spatial variations in mantle-derived isotopic and trace element ratios with implications for the temporal and spatial scales of magma injections to the crust and along-axis mixing within shallow reservoirs. These spatial variations are difficult to reconcile with significant (> ~1 km) along-axis magma transport, as are striking correlations of chemical compositions with surface geological discontinuities or seismically imaged sub-axial magma chamber reflectors in the S. Hump (S. EPR), 9°50’N EPR, N. Gorda and 1975-1984 Krafla (N. Iceland) eruptive units. Rather, spatial correlations between surface lava compositions and sub-axial magma chamber properties or long-lived axial morphology suggest that most of the erupted magma was transported nearly vertically from the underlying reservoirs to the surface during these eruptions. In the case of the Krafla eruption, coincident deformation suggests a component of lateral melt migration at depth, despite chemical evidence for vertical transport of erupted lava from more than one chemical reservoir. In addition, along-ridge movement of earthquake epicenters during the 1992 Co-Axial and 1996 Gorda eruptions implies migration of stress release during these eruptions, even though vertical transport better explains chemical patterns. The nature of transport for most eruptions is unclear because of lack of systematic chemical patterns; this presentation emphasizes those cases where vertical transport appears to be required.

Support mechanism for a mirrored surface or other arrangement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cutburth, R.W.

1987-02-03

A mechanism is described for supporting first means including a planer surface for movement relative to a vertical plane defined by particular intersecting x and y axes which extend horizontally and vertically, respectively, the mechanism comprising: (a) second means including a plurality of segments of an annular surface which forms part of a sphere whose center defines the intersection of the x and y axes. The annular surface defines a z axis extending through the intersection of the x and y axes perpendicular to the vertical plane; (b) third means connecting the planer surface including first means with the secondmore » means such that the planer surface is positionably within the vertical plane and is itself intersected by the z axis at a particular point thereon. The third means includes bearing means disposed between the first means and the segments of the annular surface of the second means for allowing the first means to move in any direction on the annular surface segments including certain specific directions which allow the planer surface to pivot back and forth to a limited extent about both the x and y axes relative to the vertical plane; and (c) fourth means interconnecting the first and second means and cooperating with the third means for limiting the movement of the first means to the certain specific directions.« less

Continued development and application of far-infrared detection techniques

NASA Technical Reports Server (NTRS)

Low, F. J.

1974-01-01

The development of a balloon gondola and pointing system are discussed which can be used with the low background far infrared telescope. Flight test progress of the new gondola is reported using a 3-axis system which would provide much greater capabilities. In this design both a polar and declination axis are use and are maintained in the proper orientation by a free handing (vertical) azimuth shaft.

Pathway Ranking for In-place Sediment Management (CU1209). Site 2 Report - Pearl Harbor

DTIC Science & Technology

2006-04-01

type resistance cell. The probe is configured with two pairs of stainless steel electrodes, the outer pair through which a known current is imposed...the “bioinhibited” (no oxygen control) deployment at BPA . Vertical axis is dissolved oxygen concentration, and horizontal axis is sample record at 6...99 Table 5-7. BFSD results from site BPA . Numbers in the Flux Rate Confidence column indicate the

Finding Lagrangian Structures via the Application of Braid Theory

DTIC Science & Technology

2010-10-16

the horizontal plane is the physical domain and the vertical axis is time. These three dimensional...three dimensional strands are projected onto the plane containing the x-axis and time then Figure 2a becomes Figure 2b. The collection of strands make...trajectories shown in the physical plane . An “x” represents the initial condition of the trajectory and a dot represents the current position. (b) The

The effect of solidity on the performance of H-rotor Darrieus turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hassan, S. M. Rakibul, E-mail: rakibulhassan21@gmail.com; Ali, Mohammad, E-mail: mali@me.buet.ac.bd; Islam, Md. Quamrul, E-mail: quamrul@me.buet.ac.bd

Utilization of wind energy has been investigated for a long period of time by different researchers in different ways. Out of which, the Horizontal Axis Wind Turbine and the Vertical Axis Wind Turbine have now advanced design, but still there is scope to improve their efficiency. The Vertical Axis Wind Turbine (VAWT) has the advantage over Horizontal Axis Wind Turbine (HAWT) for working on omnidirectional air flow without any extra control system. A modified H-rotor Darrieus type VAWT is analysed in this paper, which is a lift based wind turbine. The effect of solidity (i.e. chord length, no. of blades)more » on power coefficient (C{sub P}) of H-rotor for different tip speed ratios is numerically investigated. The study is conducted using time dependent RANS equations using SST k-ω model. SIMPLE scheme is used as pressure-velocity coupling and in all cases, the second order upwind discretization scheme is chosen for getting more accurate solution. In results, different parameters are compared, which depict the performance of the modified H-rotor Darrieus type VAWT. Double layered H-rotor having inner layer blades with longer chord gives higher power coefficient than those have inner layer blades with smaller chord.« less

Learning dynamic control of body yaw orientation.

PubMed

Vimal, Vivekanand Pandey; Lackner, James R; DiZio, Paul

2018-05-01

To investigate the role of gravitational cues in the learning of a dynamic balancing task, we placed blindfolded subjects in a device programmed with inverted pendulum dynamics about the yaw axis. Subjects used a joystick to try and maintain a stable orientation at the direction of balance during 20 100 s-long trials. They pressed a trigger button on the joystick to indicate whenever they felt at the direction of balance. Three groups of ten subjects each participated. One group balanced with their body and the yaw axis vertical, and thus did not have gravitational cues to help them to determine their angular position. They showed minimal learning, inaccurate indications of the direction of balance, and a characteristic pattern of positional drifting away from the balance point. A second group balanced with the yaw axis pitched 45° from the gravitational vertical and had gravity relevant position cues. The third group balanced with their yaw axis horizontal where they had gravity-dependent cues about body position in yaw. Groups 2 and 3 showed better initial balancing performance and more learning across trials than Group 1. These results indicate that in the absence of vision, the integration of transient semicircular canal and somatosensory signals about angular acceleration is insufficient for determining angular position during dynamic balancing; direct position-dependent gravity cues are necessary.

Friction measurement in a hip wear simulator.

PubMed

Saikko, Vesa

2016-05-01

A torque measurement system was added to a widely used hip wear simulator, the biaxial rocking motion device. With the rotary transducer, the frictional torque about the drive axis of the biaxial rocking motion mechanism was measured. The principle of measuring the torque about the vertical axis above the prosthetic joint, used earlier in commercial biaxial rocking motion simulators, was shown to sense only a minor part of the total frictional torque. With the present method, the total frictional torque of the prosthetic hip was measured. This was shown to consist of the torques about the vertical axis above the joint and about the leaning axis. Femoral heads made from different materials were run against conventional and crosslinked polyethylene acetabular cups in serum lubrication. Regarding the femoral head material and the type of polyethylene, there were no categorical differences in frictional torque with the exception of zirconia heads, with which the lowest values were obtained. Diamond-like carbon coating of the CoCr femoral head did not reduce friction. The friction factor was found to always decrease with increasing load. High wear could increase the frictional torque by 75%. With the present system, friction can be continuously recorded during long wear tests, so the effect of wear on friction with different prosthetic hips can be evaluated. © IMechE 2016.

The influence of mechanical gear on the efficiency of small hydropower

NASA Astrophysics Data System (ADS)

Ferenc, Zbigniew; Sambor, Aleksandra

2017-11-01

Pursuant to the "Strategy of development of renewable energy", an increase in the share of renewable energy sources in the national fuel-energy balance up to 14% by 2020 is planned in the structure of usage of primary energy carriers. The change in the participation of the clean energy in the energy balance may be done not only by the erection of new and renovation of the already existing plants, but also through an improvement of their energetic efficiency. The study presents the influence of the mechanical gear used on the quantity of energy produced by a small hydropower on the basis of SHP Rzepcze in Opole province in 2005-2010. The primary kinematic system was composed of a Francis turbine of a vertical axis, a toothed intersecting axis gear of 1:1 ratio, a belt gear of a double ratio. After a modernization the system was simplified by means of reducing the intersecting axis gear and the double ratio of the belt gear. The new kinematic system utilized a single-ratio belt gear of a vertical axis. After the kinematic system was rearranged, a significant improvement of efficiency of the small hydropower was concluded, which translates into an increase of the amount of energy produced.

Classifying Particles By Acoustic Levitation

NASA Technical Reports Server (NTRS)

Barmatz, Martin B.; Stoneburner, James D.

1983-01-01

Separation technique well suited to material processing. Apparatus with rectangular-cross-section chamber used to measure equilibrium positions of low-density spheres in gravitational field. Vertical acoustic forces generated by two opposing compression drivers exciting fundamental plane-wave mode at 1.2 kHz. Additional horizontal drivers centered samples along vertical axis. Applications in fusion-target separation, biological separation, and manufacturing processes in liquid or gas media.

Flight Control System Analysis and Design for a Remotely Piloted Vehicle with Thrust Vectoring Unit.

DTIC Science & Technology

1980-12-01

about the X-axis (slug-ft 2) Ixz Product of inertia (slug-ft 2 ) ly Moi,;ent of inertia about Y-axis (slug-ft 2) Iz Moment of inertia about Z-axis (slug...domain n Load factor (g’s) P Roll rate (rad/sec) xi p Perturbation roll rate (rad/sec) Q Pitch rate (rad/sec) q Perturbation pitch rate (rad/sec...was decided to employ a scale factor of 1.75 in increasing the vertical tail area. This choice was somewhat aruitrary since no documentation could be

Biased Feedback in Spatial Recall Yields a Violation of Delta Rule Learning

PubMed Central

Lipinski, John; Spencer, John P.; Samuelson, Larissa K.

2010-01-01

This study investigates whether inductive processes influencing spatial memory performance generalize to supervised learning scenarios with differential feedback. After providing a location memory response in a spatial recall task, participants received visual feedback showing the target location. In critical blocks, feedback was systematically biased either 4° towards the vertical axis (Towards condition) or 4° further away from the vertical axis (Away condition). Results showed that the weaker teaching signal (i.e., a smaller difference between the remembered location and the feedback location) in the Away condition produced a stronger experience-dependent change over blocks than in the Towards condition. This violates delta rule learning. Subsequent simulations of the Dynamic Field Theory of spatial cognition provide a theoretically unified account of these results. PMID:20702881

On the wake of a Darrieus turbine

NASA Technical Reports Server (NTRS)

Base, T. E.; Phillips, P.; Robertson, G.; Nowak, E. S.

1981-01-01

The theory and experimental measurements on the aerodynamic decay of a wake from high performance vertical axis wind turbine are discussed. In the initial experimental study, the wake downstream of a model Darrieus rotor, 28 cm diameter and a height of 45.5 cm, was measured in a Boundary Layer Wind Tunnel. The wind turbine was run at the design tip speed ratio of 5.5. It was found that the wake decayed at a slower rate with distance downstream of the turbine, than a wake from a screen with similar troposkein shape and drag force characteristics as the Darrieus rotor. The initial wind tunnel results indicated that the vertical axis wind turbines should be spaced at least forty diameters apart to avoid mutual power depreciation greater than ten per cent.

Structural design of the Sandia 34-M Vertical Axis Wind Turbine

NASA Astrophysics Data System (ADS)

Berg, D. E.

Sandia National Laboratories, as the lead DOE laboratory for Vertical Axis Wind Turbine (VAWT) development, is currently designing a 34-meter diameter Darrieus-type VAWT. This turbine will be a research test bed which provides a focus for advancing technology and validating design and fabrication techniques in a size range suitable for utility use. Structural data from this machine will allow structural modeling to be refined and verified for a turbine on which the gravity effects and stochastic wind loading are significant. Performance data from it will allow aerodynamic modeling to be refined and verified. The design effort incorporates Sandia's state-of-the-art analysis tools in the design of a complete machine. The analytic tools used in this design are discussed and the conceptual design procedure is described.

Adjoint Airfoil Optimization of Darrieus-Type Vertical Axis Wind Turbine

NASA Astrophysics Data System (ADS)

Fuchs, Roman; Nordborg, Henrik

2012-11-01

We present the feasibility of using an adjoint solver to optimize the torque of a Darrieus-type vertical axis wind turbine (VAWT). We start with a 2D cross section of a symmetrical airfoil and restrict us to low solidity ratios to minimize blade vortex interactions. The adjoint solver of the ANSYS FLUENT software package computes the sensitivities of airfoil surface forces based on a steady flow field. Hence, we find the torque of a full revolution using a weighted average of the sensitivities at different wind speeds and angles of attack. The weights are computed analytically, and the range of angles of attack is given by the tip speed ratio. Then the airfoil geometry is evolved, and the proposed methodology is evaluated by transient simulations.

Vertical axis wind turbine power regulation through centrifugally pumped lift spoiling

NASA Astrophysics Data System (ADS)

Klimas, P. C.; Sladky, J. F., Jr.

This paper describes an approach for lowering the rated windspeeds of Darrieus-type vertical axis wind turbines (VAWTs) whose blades are hollow aluminum extrusions. The blades, which when rotating act as centrifugal pumps, are fitted with a series of small perforations distributed along a portion of the blades' span. By valving the ends of the hollow blades, flow into the blade ends and out of the perforations may be controlled. This flow can induce premature aerodynamic stall on the blade elements, thereby reducing both the rated power of the turbine and its cost-of-energy. The concept has been proven on the Sandia National Laboratories 5-m diameter research VAWT and force balance and flow visualization wind tunnel tests have been conducted using a blade section designed for the VAWT application.

Field test report of the Department of Energy's 100-kW vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Nellums, R. O.

1985-02-01

Three second generation Darrieus type vertical axis wind turbines of approximately 120 kW capacity per unit were installed in 1980-1981. Through March 1984, over 9000 hours of operation had been accumulated, including 6600 hours of operation on the unit installed in Bushland, Texas. The turbines were heavily instrumented and have yielded a large amount of test data. Test results of this program, including aerodynamic, structural, drive train, and economic data are presented. Among the most favorable results were an aerodynamic peak performance coefficient of 0.41; fundamental structural integrity requiring few repairs and no major component replacements as of March 1984; and an average prototype fabrication cost of approximately $970 per peak kilowatt of output. A review of potential design improvements is presented.

Design, performance and economics of the DAF Indal 50 kW and 375 kW vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Schienbein, L. A.; Malcolm, D. J.

1982-03-01

A review of the development and performance of the DAF Indal 50 kW vertical axis Darrieus wind turbines shows that a high level of technical development and reliability has been achieved. Features of the drive train, braking and control systems are discussed and performance details are presented. A description is given of a wind-diesel hybrid presently being tested. Details are also presented of a 375 kW VAWT planned for production in late 1982. A discussion of the economics of both the 50 kW and 375 kW VAWTs is included, showing the effects of charge rate, installed cost, operating cost, performance and efficiency. The energy outputs are translated into diesel fuel cost savings for remote communities.

Dynamics of Equilibrium Points in a Uniformly Rotating Second-Order and Degree Gravitational Field

NASA Astrophysics Data System (ADS)

Feng, Jinglang; Hou, Xiyun

2017-07-01

Using tools such as periodic orbits and invariant manifolds, the global dynamics around equilibrium points (EPs) in a rotating second-order and degree gravitational field are studied. For EPs on the long axis, planar and vertical periodic families are computed, and their stability properties are investigated. Invariant manifolds are also computed, and their relation to the first-order resonances is briefly discussed. For EPs on the short axis, planar and vertical periodic families are studied, with special emphasis on the genealogy of the planar periodic families. Our studies show that the global dynamics around EPs are highly similar to those around libration points in the circular restricted three-body problem, such as spatial halo orbits, invariant manifolds, and the genealogy of planar periodic families.

Biased feedback in spatial recall yields a violation of delta rule learning.

PubMed

Lipinski, John; Spencer, John P; Samuelson, Larissa K

2010-08-01

This study investigates whether inductive processes influencing spatial memory performance generalize to supervised learning scenarios with differential feedback. After providing a location memory response in a spatial recall task, participants received visual feedback showing the target location. In critical blocks, feedback was systematically biased either 4 degrees toward the vertical axis (toward condition) or 4 degrees farther away from the vertical axis (away condition). Results showed that the weaker teaching signal (i.e., a smaller difference between the remembered location and the feedback location) produced a stronger experience-dependent change over blocks in the away condition than in the toward condition. This violates delta rule learning. Subsequent simulations of the dynamic field theory of spatial cognition provide a theoretically unified account of these results.

Dynamics of thin-film piezoelectric microactuators with large vertical stroke subject to multi-axis coupling and fabrication asymmetries

NASA Astrophysics Data System (ADS)

Choi, Jongsoo; Wang, Thomas; Oldham, Kenn

2018-01-01

The high performance and small size of MEMS based scanners has allowed various optical imaging techniques to be realized in a small form factor. Many such devices are resonant scanners, and thus their linear and nonlinear dynamic behaviors have been studied in the past. Thin-film piezoelectric materials, in contrast, provide sufficient energy density to achieve both large static displacements and high-frequency resonance, but large deformation can in turn influence dynamic scanner behavior. This paper reports on the influence of very large stroke translation of a piezoelectric vertical actuator on its resonant behavior, which may not be otherwise explained fully by common causes of resonance shift such as beam stiffening or nonlinear forcing. To examine the change of structural compliance over the course of scanner motion, a model has been developed that includes internal forces from residual stress and the resultant additional multi-axis coupling among actuator leg structures. Like some preceding vertical scanning micro-actuators, the scanner of this work has four legs, with each leg featuring four serially connected thin-film PZT unimorphs that allow the scanner to generate larger than 400 µm of vertical displacement at 14 V DC. Using an excitation near one or more resonances, the input voltage can be lowered, and complementary multi-axis rotations can be also generated, but change of the resonant frequencies with scanner height needs to be understood to maximize scanner performance. The presented model well predicts the experimental observation of the decrease of the resonant frequencies of the scanner with the increase of a dc bias voltage. Also, the effects of the magnitude and uniformity of residual stress across the scanner structure on the natural frequencies have been studied.

7. SOUTHEAST ACROSS INTERIOR OF OFFICE IN SOUTHEAST CORNER OF ...

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

7. SOUTHEAST ACROSS INTERIOR OF OFFICE IN SOUTHEAST CORNER OF BUILDING TOWARD WINDOW ON STREET, SHOWING ONE DESK, OFFICE FIXTURES, AND LETTER BOXES FILLED WITH MANUSCRIPT BUSINESS RECORDS. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

9. VIEW OF FLOOR 2 LOOKING EAST; SHOWS GREAT SPUR ...

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

9. VIEW OF FLOOR 2 LOOKING EAST; SHOWS GREAT SPUR WHEEL AND TWO STONE NUTS, AND THE CHUTES, HOPPERS, HORSES AND SHOES OF THE GRAIN FEED SYSTEM - Hook Windmill, North Main Street at Pantigo Road, East Hampton, Suffolk County, NY

5. NORTH ACROSS INTERIOR OF OFFICE IN SOUTHEAST CORNER OF ...

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

5. NORTH ACROSS INTERIOR OF OFFICE IN SOUTHEAST CORNER OF BUILDING FROM DOORWAY IN SOUTH FRONT, SHOWING DRAFTING TABLE, MERCHANDISE DISPLAY CASE, DESKS, AND OFFICE FIXTURES/BUSINESS MACHINES. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

Review of the windpower activities at the Brace Research Institute

NASA Technical Reports Server (NTRS)

Lawand, T. A.

1973-01-01

A chronology of windpower studies at the experimental station on Barbados is presented that includes the various development activities on wheeling windmills whose power output is utilized through electrical and electronic systems. A list of institute publications on windpower is included.

Vertical eye position-dependence of the human vestibuloocular reflex during passive and active yaw head rotations.

PubMed

Thurtell, M J; Black, R A; Halmagyi, G M; Curthoys, I S; Aw, S T

1999-05-01

Vertical eye position-dependence of the human vestibuloocular reflex during passive and active yaw head rotations. The effect of vertical eye-in-head position on the compensatory eye rotation response to passive and active high acceleration yaw head rotations was examined in eight normal human subjects. The stimuli consisted of brief, low amplitude (15-25 degrees ), high acceleration (4,000-6,000 degrees /s2) yaw head rotations with respect to the trunk (peak velocity was 150-350 degrees /s). Eye and head rotations were recorded in three-dimensional space using the magnetic search coil technique. The input-output kinematics of the three-dimensional vestibuloocular reflex (VOR) were assessed by finding the difference between the inverted eye velocity vector and the head velocity vector (both referenced to a head-fixed coordinate system) as a time series. During passive head impulses, the head and eye velocity axes aligned well with each other for the first 47 ms after the onset of the stimulus, regardless of vertical eye-in-head position. After the initial 47-ms period, the degree of alignment of the eye and head velocity axes was modulated by vertical eye-in-head position. When fixation was on a target 20 degrees up, the eye and head velocity axes remained well aligned with each other. However, when fixation was on targets at 0 and 20 degrees down, the eye velocity axis tilted forward relative to the head velocity axis. During active head impulses, the axis tilt became apparent within 5 ms of the onset of the stimulus. When fixation was on a target at 0 degrees, the velocity axes remained well aligned with each other. When fixation was on a target 20 degrees up, the eye velocity axis tilted backward, when fixation was on a target 20 degrees down, the eye velocity axis tilted forward. The findings show that the VOR compensates very well for head motion in the early part of the response to unpredictable high acceleration stimuli-the eye position- dependence of the VOR does not become apparent until 47 ms after the onset of the stimulus. In contrast, the response to active high acceleration stimuli shows eye position-dependence from within 5 ms of the onset of the stimulus. A model using a VOR-Listing's law compromise strategy did not accurately predict the patterns observed in the data, raising questions about how the eye position-dependence of the VOR is generated. We suggest, in view of recent findings, that the phenomenon could arise due to the effects of fibromuscular pulleys on the functional pulling directions of the rectus muscles.

Manifestations of geometric phases in a proton electric-dipole-moment experiment in an all-electric storage ring

NASA Astrophysics Data System (ADS)

Silenko, Alexander J.

2017-12-01

We consider a proton electric-dipole-moment experiment in an all-electric storage ring when the spin is frozen and local longitudinal and vertical electric fields alternate. In this experiment, the geometric (Berry) phases are very important. Due to the these phases, the spin rotates about the radial axis. The corresponding systematic error is rather important while it can be canceled with clockwise and counterclockwise beams. The geometric phases also lead to the spin rotation about the radial axis. This effect can be canceled with clockwise and counterclockwise beams as well. The sign of the azimuthal component of the angular velocity of the spin precession depends on the starting point where the spin orientation is perfect. The radial component of this quantity keeps its value and sign for each starting point. When the longitudinal and vertical electric fields are joined in the same sections without any alternation, the systematic error due to the geometric phases does not appear but another systematic effect of the spin rotation about the azimuthal axis takes place. It has opposite signs for clockwise and counterclockwise beams.

Fixed Base Modal Testing Using the NASA GRC Mechanical Vibration Facility

NASA Technical Reports Server (NTRS)

Staab, Lucas D.; Winkel, James P.; Suarez, Vicente J.; Jones, Trevor M.; Napolitano, Kevin L.

2016-01-01

The Space Power Facility at NASA's Plum Brook Station houses the world's largest and most powerful space environment simulation facilities, including the Mechanical Vibration Facility (MVF), which offers the world's highest-capacity multi-axis spacecraft shaker system. The MVF was designed to perform sine vibration testing of a Crew Exploration Vehicle (CEV)-class spacecraft with a total mass of 75,000 pounds, center of gravity (cg) height above the table of 284 inches, diameter of 18 feet, and capability of 1.25 gravity units peak acceleration in the vertical and 1.0 gravity units peak acceleration in the lateral directions. The MVF is a six-degree-of-freedom, servo-hydraulic, sinusoidal base-shake vibration system that has the advantage of being able to perform single-axis sine vibration testing of large structures in the vertical and two lateral axes without the need to reconfigure the test article for each axis. This paper discusses efforts to extend the MVF's capabilities so that it can also be used to determine fixed base modes of its test article without the need for an expensive test-correlated facility simulation.

Computational analysis of vertical axis wind turbine arrays

NASA Astrophysics Data System (ADS)

Bremseth, J.; Duraisamy, K.

2016-10-01

Canonical problems involving single, pairs, and arrays of vertical axis wind turbines (VAWTs) are investigated numerically with the objective of understanding the underlying flow structures and their implications on energy production. Experimental studies by Dabiri (J Renew Sustain Energy 3, 2011) suggest that VAWTs demand less stringent spacing requirements than their horizontal axis counterparts and additional benefits may be obtained by optimizing the placement and rotational direction of VAWTs. The flowfield of pairs of co-/counter-rotating VAWTs shows some similarities with pairs of cylinders in terms of wake structure and vortex shedding. When multiple VAWTs are placed in a column, the extent of the wake is seen to spread further downstream, irrespective of the direction of rotation of individual turbines. However, the aerodynamic interference between turbines gives rise to regions of excess momentum between the turbines which lead to significant power augmentations. Studies of VAWTs arranged in multiple columns show that the downstream columns can actually be more efficient than the leading column, a proposition that could lead to radical improvements in wind farm productivity.

A multidimensional model of the effect of gravity on the spatial orientation of the monkey

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Young, L. R.; Oman, C. M.; Shelhamer, M. J.

1993-01-01

A "sensory conflict" model of spatial orientation was developed. This mathematical model was based on concepts derived from observer theory, optimal observer theory, and the mathematical properties of coordinate rotations. The primary hypothesis is that the central nervous system of the squirrel monkey incorporates information about body dynamics and sensory dynamics to develop an internal model. The output of this central model (expected sensory afference) is compared to the actual sensory afference, with the difference defined as "sensory conflict." The sensory conflict information is, in turn, used to drive central estimates of angular velocity ("velocity storage"), gravity ("gravity storage"), and linear acceleration ("acceleration storage") toward more accurate values. The model successfully predicts "velocity storage" during rotation about an earth-vertical axis. The model also successfully predicts that the time constant of the horizontal vestibulo-ocular reflex is reduced and that the axis of eye rotation shifts toward alignment with gravity following postrotatory tilt. Finally, the model predicts the bias, modulation, and decay components that have been observed during off-vertical axis rotations (OVAR).

Dynamic modeling and vibration characteristics analysis of the aero-engine dual-rotor system with Fan blade out

NASA Astrophysics Data System (ADS)

Yu, Pingchao; Zhang, Dayi; Ma, Yanhong; Hong, Jie

2018-06-01

Fan Blade Out (FBO) from a running rotor of the turbofan engine will not only introduce the sudden unbalance and inertia asymmetry into the rotor, but also apply large impact load and induce rotor-to-stator rubbing on the rotor, which makes the mass, gyroscopic and stiffness matrixes of the dynamic equation become time-varying and highly nonlinear, consequently leads to the system's complicated vibration. The dynamic analysis of the aero-engine rotor system is one essential requirement of the authorities and is vital to the aero-engine's safety. The paper aims at studying the dynamic responses of the complicated dual-rotor systems at instantaneous and windmilling statuses when FBO event occurs. The physical process and mechanical characteristics of the FBO event are described qualitatively, based on which the dynamic modeling for an aero-engine dual-rotor system is carried out considering several excitations caused by FBO. Meanwhile the transient response during the instantaneous status and steady-state response at the windmilling status are obtained. The results reveal that the sudden unbalance can induce impact load to the rotor, and lead to the sharp increase of the vibration amplitude and reaction force. The rub-impact will apply constraint effects on the rotor and restrict the transient vibration amplitude, while the inertia asymmetry has little influence on the transient response. When the rotor with huge unbalance operates at windmilling status, the rub-impact turns to be the main factor determining the rotor's dynamic behavior, and several potential motion states, such as instable dry whip, intermittent rubbing and synchronous full annular rubbing would happen on certain conditions.

Phonation Quotient in Women: A Measure of Vocal Efficiency Using Three Aerodynamic Instruments.

PubMed

Joshi, Ashwini; Watts, Christopher R

2017-03-01

The purpose of this study was to examine measures of vital capacity and phonation quotient across three age groups in women using three different aerodynamic instruments representing low-tech and high-tech options. This study has a prospective, repeated measures design. Fifteen women in each age group of 25-39 years, 40-59 years, and 60-79 years were assessed using maximum phonation time and vital capacity obtained from three aerodynamic instruments: a handheld analog windmill type spirometer, a handheld digital spirometer, and the Phonatory Aerodynamic System (PAS), Model 6600. Phonation quotient was calculated using vital capacity from each instrument. Analyses of variance were performed to test for main effects of the instruments and age on vital capacity and derived phonation quotient. Pearson product moment correlation was performed to assess measurement reliability (parallel forms) between the instruments. Regression equations, scatterplots, and coefficients of determination were also calculated. Statistically significant differences were found in vital capacity measures for the digital spirometer compared with the windmill-type spirometer and PAS across age groups. Strong positive correlations were present between all three instruments for both vital capacity and derived phonation quotient measurements. Measurement precision for the digital spirometer was lower than the windmill spirometer compared with the PAS. However, all three instruments had strong measurement reliability. Additionally, age did not have an effect on the measurement across instruments. These results are consistent with previous literature reporting data from male speakers and support the use of low-tech options for measurement of basic aerodynamic variables associated with voice production. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Continuously Deformation Monitoring of Subway Tunnel Based on Terrestrial Point Clouds

NASA Astrophysics Data System (ADS)

Kang, Z.; Tuo, L.; Zlatanova, S.

2012-07-01

The deformation monitoring of subway tunnel is of extraordinary necessity. Therefore, a method for deformation monitoring based on terrestrial point clouds is proposed in this paper. First, the traditional adjacent stations registration is replaced by sectioncontrolled registration, so that the common control points can be used by each station and thus the error accumulation avoided within a section. Afterwards, the central axis of the subway tunnel is determined through RANSAC (Random Sample Consensus) algorithm and curve fitting. Although with very high resolution, laser points are still discrete and thus the vertical section is computed via the quadric fitting of the vicinity of interest, instead of the fitting of the whole model of a subway tunnel, which is determined by the intersection line rotated about the central axis of tunnel within a vertical plane. The extraction of the vertical section is then optimized using RANSAC for the purpose of filtering out noises. Based on the extracted vertical sections, the volume of tunnel deformation is estimated by the comparison between vertical sections extracted at the same position from different epochs of point clouds. Furthermore, the continuously extracted vertical sections are deployed to evaluate the convergent tendency of the tunnel. The proposed algorithms are verified using real datasets in terms of accuracy and computation efficiency. The experimental result of fitting accuracy analysis shows the maximum deviation between interpolated point and real point is 1.5 mm, and the minimum one is 0.1 mm; the convergent tendency of the tunnel was detected by the comparison of adjacent fitting radius. The maximum error is 6 mm, while the minimum one is 1 mm. The computation cost of vertical section abstraction is within 3 seconds/section, which proves high efficiency..

The influence of passive-dynamic ankle-foot orthosis bending axis location on gait performance in individuals with lower-limb impairments.

PubMed

Ranz, Ellyn C; Russell Esposito, Elizabeth; Wilken, Jason M; Neptune, Richard R

2016-08-01

Passive-dynamic ankle-foot orthoses are commonly prescribed to augment impaired ankle muscle function, however their design and prescription are largely qualitative. One design includes a footplate and cuff, and flexible strut connecting the two. During gait, deflection occurs along the strut, with the greatest deflection at a central bending axis. The vertical location of the axis can affect lower extremity biomechanics. The goal of this study was to investigate the influence of bending axis location on gait performance. For thirteen participants with unilateral ankle muscle weakness, an additive manufacturing framework was used to fabricate passive-dynamic ankle-foot orthosis struts with central and off-center bending axes. Participants walked overground while electromyographic, kinetic and kinematic data were collected for three different bending axes: proximal (high), central (middle) and distal (low), and the participants indicated their order of bending axis preference after testing. Gait measures and preference effect sizes were examined during six regions of the gait cycle. A few differences between bending axes were observed: in the first double-leg support peak plantarflexion angle, peak dorsiflexion moment and positive hip work, in the early single-leg support peak knee extension moment and positive ankle and knee work, and in the late single-leg support gastrocnemius activity and vertical ground reaction force impulse. In addition, preference was strongly related to various gait measures. Despite the observed statistical differences, altering bending axis location did not produce large and consistent changes in gait performance. Thus, individual preference and comfort may be more important factors guiding prescription. Copyright © 2016 Elsevier Ltd. All rights reserved.

Formative Justice: The Regulative Principle of Education

ERIC Educational Resources Information Center

McClintock, Robert

2016-01-01

Background/Context: Concepts of justice relevant to making personal and public decisions about education. Purpose: To clarify a concept of formative justice that persons and the public often ignore in making decisions about educational effort. Setting: "The windmills of your mind" Research Design: Reflective essay.…

Airship-windmill

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engelsman, G.J.

1984-09-11

From one or more lighter than air bodies, carrying wind energy catching rotor devices, like windmills, turbines or the like, the caught energy is mechanically transmitted to earth by at least one endless cable-rope transmission. Each of the cables is led over an individual sheave fitted to a turntable on earth (ground, ship, float or so), from which it drives a stationary machine, like a generator or such, and cable guide rolls are provided as needed. All functions of forcetransmission, consisting of energy transmission, wind-resistance and upward-floating forces and steering are performed by the turntable through the endless energy transmissionmore » cable(s), and no tethering or other force-transmitting cables are applied. In addition a loose, very low tensioned communication line for control, gas supply and the like extends from the turntalbe to the floating parts. Cable guide rolls are provided as needed. The design aims for a simple installation which avoids cables getting entangled when wind direction changes suddenly or in absolute calm.« less

Wind-energy recovery by a static Scherbius induction generator

NASA Astrophysics Data System (ADS)

Smith, G. A.; Nigim, K. A.

1981-11-01

The paper describes a technique for controlling a doubly fed induction generator driven by a windmill, or other form of variable-speed prime mover, to provide power generation into the national grid system. The secondary circuit of the generator is supplied at a variable frequency from a current source inverter which for test purposes is rated to allow energy recovery, from a simulated windmill, from maximum speed to standstill. To overcome the stability problems normally associated with doubly fed machines a novel signal generator, which is locked in phase with the rotor EMF, controls the secondary power to provide operation over a wide range of subsynchronous and supersynchronous speeds. Consideration of power flow enables the VA rating of the secondary power source to be determined as a function of the gear ratio and online operating range of the system. A simple current source model is used to predict performance which is compared with experimental results. The results indicate a viable system, and suggestions for further work are proposed.

Which is riskier: windmills or reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cromie, W.J.

1980-03-01

In 1978, Dr. Herbert Inhaber, a scientist employed by the Atomic Energy Board of Canada, published an evaluation of the health hazards of different energy systems entitled Risk of Energy Production. He concluded that natural gas and nuclear systems are safer than coal- and oil-fired power plants, hydroelectricity, various forms of solar energy, windmills, methanol (wood alcohol), and other nonconventional energy sources. The report and its conclusions drew widespread criticism, particularly from Dr. John P. Holdren, professor of energy and resources, University of California at Berkeley. Holdren and five colleagues wrote a stinging 232-page critique of the Inhaber report. Themore » Council for the Advancement of Science Writing, a nonprofit educational organization of writers and scientists, invited the two to debate the issue in front of an audience of science reporters. The confrontation took place at CASW's 17th Annual New Horizons in Science Briefing in Palo Alto, Calif., on Nov. 5, 1979. An edited transcript of the debate is presented here.« less

Flight Test of the Lateral Stability of a 0.133-Scale Model of the Convair XFY-1 Airplane with Windmilling Propellers at Mach Numbers from 0.70 to 1.12 (TED No. NACA DE 369)

NASA Technical Reports Server (NTRS)

Hollinger, James A.; Mitcham, Grady L.

1955-01-01

A flight test of a rocket-propelled model of the Convair XFY-1 airplane was conducted to determine the lateral stability and control characteristics, The 0.133-scale model had windmilling propellers for this test, which covered a Mach number range of O.70 to 1.12. The center of gravity was located at 13.9 percent of the mean aerodynamic chord. The methods of analysis included both a solution by vector diagrams and simple one- and two-degree-of-freedom methods. The model was both statically and dynamically stable throughout the speed range of the testa The roll damping was good, and the slope of the side-force curve varied little with speed. The rudder was effective throughout the test speed range, although it was reduced to about 43 percent of its subsonic value at supersonic speeds.

Holocene Deglaciation, Sea-Level Change, and the Emergence of the Windmill Islands, Budd Coast, Antarctica

NASA Astrophysics Data System (ADS)

Goodwin, Ian D.

1993-07-01

A Holocene deglaciation sequence for the Windmill Islands was determined from the 14C age of raised marine shorelines, lakebottom sediments, and Adelie penguin remains found in abandoned rookeries. A north-south gradient in the elevation of the upper marine limit was observed, with the highest marine limit (31-32 m) observed on Browning Peninsula and Hull Island at the southern edge of the islands. Correspondingly, the southern islands were found to have been deglaciated by 8000 (corr.) yr B.P. while the northern islands were deglaciated by 5500 (corr.) yr B.P. Isostatic uplift rates were calculated as 0.5 to 0.6 m/100 yr, with an estimated total uplift of around 53 m which indicates late Pleistocene ice sheet thicknesses of 200 and 400 m over the islands and adjacent Petersen Bank, respectively. The margin of the Late Pleistocene grounded ice sheet extended an estimated 8-15 km offshore which coincides with the location of the 200 m isobath.

Adaptive changes in the angular VOR: duration of gain changes and lack of effect of nodulo-uvulectomy.

PubMed

Yakushin, Sergei B; Bukharina, Svetlana E; Raphan, Theodore; Buttner-Ennever, Jean; Cohen, Bernard

2003-10-01

Alterations in the gain of the vertical angular vestibulo-ocular reflex (VOR) are dependent on the head position in which the gain changes were produced. We determined how long gravity-dependent gain changes last in monkeys after four hours of adaptation, and whether the adaptation is mediated through the nodulus and uvula of the vestibulocerebellum. Vertical VOR gains were adaptively modified by rotation about an interaural axis, in phase or out of phase with the visual surround. Vertical VOR gains were modified with the animals in one of three orientations: upright, left-side down, or right-side down. Monkeys were tested in darkness for up to four days after adaptation using sinusoidal rotation about an interaural axis that was incrementally tilted in 10 degrees steps from vertical to side down positions. Animals were unrestrained in their cages in normal light conditions between tests. Gravity-dependent gain changes lasted for a day or less after adaptation while upright, but persisted for two days or more after on-side adaptation. These data show that gravity-dependent gain changes can last for prolonged periods after only four hours of adaptation in monkeys, as in humans. They also demonstrate that natural head movements made while upright do not provide an adequate stimulus for rapid recovery of vertical VOR gains that were induced on side. In two animals, the nodulus and uvula were surgically ablated. Vertical gravity-dependent gain changes were not significantly different before and after surgery, indicating that the nodulus and uvula do not have a critical role in producing them.

Image characterization metrics for muon tomography

NASA Astrophysics Data System (ADS)

Luo, Weidong; Lehovich, Andre; Anashkin, Edward; Bai, Chuanyong; Kindem, Joel; Sossong, Michael; Steiger, Matt

2014-05-01

Muon tomography uses naturally occurring cosmic rays to detect nuclear threats in containers. Currently there are no systematic image characterization metrics for muon tomography. We propose a set of image characterization methods to quantify the imaging performance of muon tomography. These methods include tests of spatial resolution, uniformity, contrast, signal to noise ratio (SNR) and vertical smearing. Simulated phantom data and analysis methods were developed to evaluate metric applicability. Spatial resolution was determined as the FWHM of the point spread functions in X, Y and Z axis for 2.5cm tungsten cubes. Uniformity was measured by drawing a volume of interest (VOI) within a large water phantom and defined as the standard deviation of voxel values divided by the mean voxel value. Contrast was defined as the peak signals of a set of tungsten cubes divided by the mean voxel value of the water background. SNR was defined as the peak signals of cubes divided by the standard deviation (noise) of the water background. Vertical smearing, i.e. vertical thickness blurring along the zenith axis for a set of 2 cm thick tungsten plates, was defined as the FWHM of vertical spread function for the plate. These image metrics provided a useful tool to quantify the basic imaging properties for muon tomography.

Design of h-Darrieus vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Parra, Teresa; Vega, Carmen; Gallegos, A.; Uzarraga, N. C.; Castro, F.

2015-05-01

Numerical simulation is used to predict the performance of a Vertical Axis Wind Turbine (VAWT) H-Darrieus. The rotor consists of three straight blades with shape of aerofoil of the NACA family attached to a rotating vertical shaft. The influence of the solidity is tested to get design tendencies. The mesh has two fluid volumes: one sliding mesh for the rotor where the rotation velocity is established while the other is the environment of the rotor. Bearing in mind the overall flow is characterized by important secondary flows, the turbulence model selected was realizable k-epsilon with non-equilibrium wall functions. Conservation equations were solved with a Third-Order Muscl scheme using SIMPLE to couple pressure and velocity. During VAWT operation, the performance depends mainly on the relative motion of the rotating blade and has a fundamental period which depends both on the rate of rotation and the number of blades. The transient study is necessary to characterise the hysteresis phenomenon. Hence, more than six revolutions get the periodic behaviour. Instantaneous flows provide insight about wake structure interaction. Time averaged parameters let obtain the characteristic curves of power coefficient.

Radiation Measurements on Mars

NASA Image and Video Library

2013-12-09

Micrograys are unit of measurement for absorbed radiation dose. The vertical axis is in micrograys per day. The RAD instrument on NASA Curiosity Mars rover monitors the natural radiation environment at the surface of Mars.

Dynamics of Equilibrium Points in a Uniformly Rotating Second-Order and Degree Gravitational Field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Jinglang; Hou, Xiyun, E-mail: jinglang@nju.edu.cn, E-mail: silence@nju.edu.cn

2017-07-01

Using tools such as periodic orbits and invariant manifolds, the global dynamics around equilibrium points (EPs) in a rotating second-order and degree gravitational field are studied. For EPs on the long axis, planar and vertical periodic families are computed, and their stability properties are investigated. Invariant manifolds are also computed, and their relation to the first-order resonances is briefly discussed. For EPs on the short axis, planar and vertical periodic families are studied, with special emphasis on the genealogy of the planar periodic families. Our studies show that the global dynamics around EPs are highly similar to those around libration points in the circularmore » restricted three-body problem, such as spatial halo orbits, invariant manifolds, and the genealogy of planar periodic families.« less

Improved double-multiple streamtube model for the Darrieus-type vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Berg, D. E.

Double streamtube codes model the curved blade (Darrieus-type) vertical axis wind turbine (VAWT) as a double actuator fish arrangement (one half) and use conservation of momentum principles to determine the forces acting on the turbine blades and the turbine performance. Sandia National Laboratories developed a double multiple streamtube model for the VAWT which incorporates the effects of the incident wind boundary layer, nonuniform velocity between the upwind and downwind sections of the rotor, dynamic stall effects and local blade Reynolds number variations. The theory underlying this VAWT model is described, as well as the code capabilities. Code results are compared with experimental data from two VAWT's and with the results from another double multiple streamtube and a vortex filament code. The effects of neglecting dynamic stall and horizontal wind velocity distribution are also illustrated.

Strain gauge validation experiments for the Sandia 34-meter VAWT (Vertical Axis Wind Turbine) test bed

NASA Astrophysics Data System (ADS)

Sutherland, Herbert J.

1988-08-01

Sandia National Laboratories has erected a research oriented, 34- meter diameter, Darrieus vertical axis wind turbine near Bushland, Texas. This machine, designated the Sandia 34-m VAWT Test Bed, is equipped with a large array of strain gauges that have been placed at critical positions about the blades. This manuscript details a series of four-point bend experiments that were conducted to validate the output of the blade strain gauge circuits. The output of a particular gauge circuit is validated by comparing its output to equivalent gauge circuits (in this stress state) and to theoretical predictions. With only a few exceptions, the difference between measured and predicted strain values for a gauge circuit was found to be of the order of the estimated repeatability for the measurement system.

Experimental and Computational Investigations of Vertical Axis Wind Turbine Enclosed with Flanged Diffuser

NASA Astrophysics Data System (ADS)

Surya Raj, G.; Sangeetha, N.; Prince, M.

2018-02-01

Generation of wind energy is a must to meet out additional demand. To meet out the additional demand several long term plans were considered now being taken up for generation of energy for the fast developing industries. Detailed researches were since taken up to improve the efficiency of such vertical axis wind turbine (VAWT). In this work VAWT with diffuser and without diffuser arrangement are considered for experimental and analysis. Five diffusers were since provided around its blades of VAWT which will be placed inside a pentagon shaped fabricated structure. In this power output of the diffuser based VAWT arrangement were studied in both numerical and experimental methods and related with that of a bared VAWT. Finally, it was found that the output power of diffuser based VAWT generates approximately two times than that of bared VAWT.

Wind tunnel study of helical and straight-bladed vertical-axis wind turbine wakes

NASA Astrophysics Data System (ADS)

Bagheri, Maryam; Araya, Daniel

2017-11-01

It is hypothesized that blade curvature can serve as a passive means to control fluid entrainment and wake recovery in vertical-axis wind turbine (VAWT) arrays. We test this experimentally in a wind tunnel using two different VAWT configurations, one with straight blades and another with helical blades, keeping all other experimental parameters fixed. A small-scale, commercially available VAWT (15W max power) is used as the baseline wind tunnel model in each case. The commercial VAWT blades are replaced with either straight or helical blades that are 3D-printed extrusions of the same airfoil cross-section. Results from smoke flow visualization, three-component wake velocity measurements, and turbine power data are presented. These results give insight into the potential use of VAWTs with curved blades in utility-scale wind farms.

Experimental data on load test and performance parameters of a LENZ type vertical axis wind turbine in open environment condition.

PubMed

Sivamani, Seralathan; T, Micha Premkumar; Sohail, Mohammed; T, Mohan; V, Hariram

2017-12-01

Performance and load testing data of a three bladed two stage LENZ type vertical axis wind turbine from the experiments conducted in an open environment condition at Hindustan Institute of Technology and Science, Chennai (location 23.2167°N, 72.6833°E) are presented here. Low-wind velocity ranging from 2 to 11 m/s is available everywhere irrespective of climatic seasons and this data provides the support to the researchers using numerical tool to validate and develop an enhanced Lenz type design. Raw data obtained during the measurements are processed and presented in the form so as to compare with other typical outputs. The data is measured at different wind speeds prevalent in the open field condition ranging from 3 m/s to 9 m/s.

Omnidirectional, circularly polarized, cylindrical microstrip antenna

NASA Technical Reports Server (NTRS)

Stanton, Philip H. (Inventor)

1985-01-01

A microstrip cylindrical antenna comprised of two concentric subelements on a ground cylinder, a vertically polarized (E-field parallel to the axis of the antenna cylinder) subelement on the inside and a horizontally polarized (E-field perpendicular to the axis) subelement on the outside. The vertical subelement is a wraparound microstrip radiator. A Y-shaped microstrip patch configuration is used for the horizontally polarized radiator that is wrapped 1.5 times to provide radiating edges on opposite sides of the cylindrical antenna for improved azimuthal pattern uniformity. When these subelements are so fed that their far fields are equal in amplitude and phased 90.degree. from each other, a circularly polarized EM wave results. By stacking a plurality of like antenna elements on the ground cylinder, a linear phased array antenna is provided that can be beam steered to the desired elevation angle.

Guy cable design and damping for vertical axis wind turbines

NASA Technical Reports Server (NTRS)

Carne, T. G.

1981-01-01

Guy cables are frequently used to support vertical axis wind turbines since guying the turbine reduces some of the structural requirements on the tower. The guys must be designed to provide both the required strength and the required stiffness at the top of the turbine. The axial load which the guys apply to the tower, bearings, and foundations is an undesirable consequence of using guys to support the turbine. Limiting the axial load so that it does not significantly affect the cost of the turbine is an important objective of the cable design. The lateral vibrations of the cables is another feature of the cable design which needs to be considered. These aspects of the cable design are discussed, and a technique for damping cable vibrations was mathematically analyzed and demonstrated with experimental data.

Field investigation of a wake structure downwind of a VANT (Vertical-Axis Wind Turbine) in a wind farm array

NASA Astrophysics Data System (ADS)

Liu, H. T.; Buck, J. W.; Germain, A. C.; Hinchee, M. E.; Solt, T. S.; Leroy, G. M.; Srnsky, R. A.

1988-09-01

The effects of upwind turbine wakes on the performance of a FloWind 17-m vertical-axis wind turbine (VAWT) were investigated through a series of field experiments conducted at the FloWind wind farm on Cameron Ridge, Tehachapi, California. From the field measurements, we derived the velocity and power/energy deficits under various turbine on/off configurations. Much information was provided to characterize the structure of VAWT wakes and to assess their effects on the performance of downwind turbines. A method to estimate the energy deficit was developed based on the measured power deficit and the wind speed distributions. This method may be adopted for other turbine types and sites. Recommendations are made for optimizing wind farm design and operations, as well as for wind energy management.

SOLARIS 3-axis high load, low profile, high precision motorized positioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Acome, Eric; Van Every, Eric; Deyhim, Alex, E-mail: adc@adc9001.com

A 3-axis optical table, shown in Figure 1, was designed, fabricated, and assembled for the SOLARIS synchrotron facility at the Jagiellonian University in Krakow, Poland. To accommodate the facility, the table was designed to be very low profile, as seen in Figure 2, and bear a high load. The platform has degrees of freedom in the vertical (Z) direction as well as horizontal transversal (X and Y) directions. The table is intended to sustain loads as large as 1500 kg which will be sufficient to support a variety of equipment to measure and facilitate synchrotron radiation. After assembly, the tablemore » was tested and calibrated to find its position error in the vertical direction. ADC has extensive experience designing and building custom complex high precision motion systems [1,2].« less

Design of multi-energy Helds coupling testing system of vertical axis wind power system

NASA Astrophysics Data System (ADS)

Chen, Q.; Yang, Z. X.; Li, G. S.; Song, L.; Ma, C.

2016-08-01

The conversion efficiency of wind energy is the focus of researches and concerns as one of the renewable energy. The present methods of enhancing the conversion efficiency are mostly improving the wind rotor structure, optimizing the generator parameters and energy storage controller and so on. Because the conversion process involves in energy conversion of multi-energy fields such as wind energy, mechanical energy and electrical energy, the coupling effect between them will influence the overall conversion efficiency. In this paper, using system integration analysis technology, a testing system based on multi-energy field coupling (MEFC) of vertical axis wind power system is proposed. When the maximum efficiency of wind rotor is satisfied, it can match to the generator function parameters according to the output performance of wind rotor. The voltage controller can transform the unstable electric power to the battery on the basis of optimizing the parameters such as charging times, charging voltage. Through the communication connection and regulation of the upper computer system (UCS), it can make the coupling parameters configure to an optimal state, and it improves the overall conversion efficiency. This method can test the whole wind turbine (WT) performance systematically and evaluate the design parameters effectively. It not only provides a testing method for system structure design and parameter optimization of wind rotor, generator and voltage controller, but also provides a new testing method for the whole performance optimization of vertical axis wind energy conversion system (WECS).

Vertically stabilized elongated cross-section tokamak

DOEpatents

Sheffield, George V.

1977-01-01

This invention provides a vertically stabilized, non-circular (minor) cross-section, toroidal plasma column characterized by an external separatrix. To this end, a specific poloidal coil means is added outside a toroidal plasma column containing an endless plasma current in a tokamak to produce a rectangular cross-section plasma column along the equilibrium axis of the plasma column. By elongating the spacing between the poloidal coil means the plasma cross-section is vertically elongated, while maintaining vertical stability, efficiently to increase the poloidal flux in linear proportion to the plasma cross-section height to achieve a much greater plasma volume than could be achieved with the heretofore known round cross-section plasma columns. Also, vertical stability is enhanced over an elliptical cross-section plasma column, and poloidal magnetic divertors are achieved.

Tilting at windmills: 20 years of Hippeastrum breeding

USDA-ARS?s Scientific Manuscript database

Hippeastrum Herbert, amaryllis, has yielded popular large-flowered hybrids over a 200-year breeding history, with the Netherlands and South Africa currently dominating the market. The USDA breeding program is now almost ten years old, built upon a ten-year previous history at the University of Flori...

14 CFR 25.149 - Minimum control speed.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (7) If applicable, the propeller of the inoperative engine— (i) Windmilling; (ii) In the most..., the propeller of the inoperative engine in the position it achieves without pilot action, assuming the... propeller of the more critical inoperative engine in the position it achieves without pilot action, assuming...

14 CFR 25.149 - Minimum control speed.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (7) If applicable, the propeller of the inoperative engine— (i) Windmilling; (ii) In the most..., the propeller of the inoperative engine in the position it achieves without pilot action, assuming the... propeller of the more critical inoperative engine in the position it achieves without pilot action, assuming...

14 CFR 25.149 - Minimum control speed.

Code of Federal Regulations, 2012 CFR

2012-01-01

... (7) If applicable, the propeller of the inoperative engine— (i) Windmilling; (ii) In the most..., the propeller of the inoperative engine in the position it achieves without pilot action, assuming the... propeller of the more critical inoperative engine in the position it achieves without pilot action, assuming...

Spiral optical designs for nonimaging applications

NASA Astrophysics Data System (ADS)

Zamora, Pablo; Benítez, Pablo; Miñano, Juan C.; Vilaplana, Juan; Buljan, Marina

2011-10-01

Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. In some demanding nonimaging applications, these restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. Some of these spiral symmetry examples will be shown here, as well as their simulated results.

Spiral nonimaging optical designs

NASA Astrophysics Data System (ADS)

Zamora, Pablo; Benítez, Pablo; Miñano, Juan C.; Vilaplana, Juan

2011-10-01

Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. In some demanding nonimaging applications, these restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. Some of these spiral symmetry examples will be shown here, as well as their simulated results.

Novel freeform optical surface design with spiral symmetry

NASA Astrophysics Data System (ADS)

Zamora, Pablo; Benítez, Pablo; Miñano, Juan C.; Vilaplana, Juan

2011-10-01

Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. These restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern when dealing with optical design. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. The general designing procedure will be described in detail.

Reduced Oblique Effect in Children with Autism Spectrum Disorders (ASD)

PubMed Central

Sysoeva, Olga V.; Davletshina, Maria A.; Orekhova, Elena V.; Galuta, Ilia A.; Stroganova, Tatiana A.

2016-01-01

People are very precise in the discrimination of a line orientation relative to the cardinal (vertical and horizontal) axes, while their orientation discrimination sensitivity along the oblique axes is less refined. This difference in discrimination sensitivity along cardinal and oblique axes is called the “oblique effect.” Given that the oblique effect is a basic feature of visual processing with an early developmental origin, its investigation in children with Autism Spectrum Disorder (ASD) may shed light on the nature of visual sensory abnormalities frequently reported in this population. We examined line orientation sensitivity along oblique and vertical axes in a sample of 26 boys with ASD (IQ > 68) and 38 typically developing (TD) boys aged 7–15 years, as well as in a subsample of carefully IQ-matched ASD and TD participants. Children were asked to detect the direction of tilt of a high-contrast black-and-white grating relative to vertical (90°) or oblique (45°) templates. The oblique effect was reduced in children with ASD as compared to TD participants, irrespective of their IQ. This reduction was due to poor orientation sensitivity along the vertical axis in ASD children, while their ability to discriminate line orientation along the oblique axis was unaffected. We speculate that this deficit in sensitivity to vertical orientation may reflect disrupted mechanisms of early experience-dependent learning that takes place during the critical period for orientation selectivity. PMID:26834540

Grasp and index finger reach zone during one-handed smartphone rear interaction: effects of task type, phone width and hand length.

PubMed

Lee, Songil; Kyung, Gyouhyung; Lee, Jungyong; Moon, Seung Ki; Park, Kyoung Jong

2016-11-01

Recently, some smartphones have introduced index finger interaction functions on the rear surface. The current study investigated the effects of task type, phone width, and hand length on grasp, index finger reach zone, discomfort, and muscle activation during such interaction. We considered five interaction tasks (neutral, comfortable, maximum, vertical, and horizontal strokes), two device widths (60 and 90 mm) and three hand lengths. Horizontal (vertical) strokes deviated from the horizontal axis in the range from -10.8° to -13.5° (81.6-88.4°). Maximum strokes appeared to be excessive as these caused 43.8% greater discomfort than did neutral strokes. The 90-mm width also appeared to be excessive as it resulted in 12.3% increased discomfort relative to the 60-mm width. The small-hand group reported 11.9-18.2% higher discomfort ratings, and the percent maximum voluntary exertion of their flexor digitorum superficialis muscle, pertaining to index finger flexion, was also 6.4% higher. These findings should be considered to make smartphone rear interaction more comfortable. Practitioner Summary: Among neutral, comfortable, maximum, horizontal, and vertical index finger strokes on smartphone rear surfaces, maximum vs. neutral strokes caused 43.8% greater discomfort. Horizontal (vertical) strokes deviated from the horizontal (vertical) axis. Discomfort increased by 12.3% with 90-mm- vs. 60-mm-wide devices. Rear interaction regions of five commercialised smartphones should be lowered 20 to 30 mm for more comfortable rear interaction.

Method and apparatus for measuring shear modulus and viscosity of a monomolecular film

DOEpatents

Abraham, B.M.; Miyano, K.; Ketterson, J.B.

1983-10-18

Apparatus for measuring the shear modulus of a monomolecular film comprises a circular trough having inwardly sloping sides containing a liquid for supporting the monolayer on the surface thereof; a circular rotor suspended above the trough such that the lower surface of the rotor contacts the surface of the liquid, positioned such that the axis of the rotor is concentric with the axis of the trough and freely rotable about its axis; means for hydrostatically compressing the monolayer in the annular region formed between the rotor and the sides of the trough; and means for rotating the trough about its axis. Preferably, hydrostatic compression of the monolayer is achieved by removing liquid from the bottom of the trough (decreasing the surface area) while raising the trough vertically along its axis to maintain the monolayer at a constant elevation (and maintain rotor contact). In order to measure viscosity, a means for rotating the rotor about its axis is added to the apparatus.

Method and apparatus for measuring shear modulus and viscosity of a monomolecular film

DOEpatents

Abraham, Bernard M.; Miyano, Kenjiro; Ketterson, John B.

1985-01-01

Instrument for measuring the shear modulus of a monomolecular film comprises a circular trough having inwardly sloping sides containing a liquid for supporting the monolayer on the surface thereof; a circular rotor suspended above the trough such that the lower surface of the rotor contacts the surface of the liquid, positioned such that the axis of the rotor is concentric with the axis of the trough and freely rotable about its axis; apparatus for hydrostatically compressing the monolayer in the annular region formed between the rotor and the sides of the trough; and apparatus for rotating the trough about its axis. Preferably, hydrostatic compression of the monolayer is achieved by removing liquid from the bottom of the trough (decreasing the surface area) while raising the trough vertically along its axis to maintain the monolayer at a constant elevation (and maintain rotor contact). In order to measure viscosity, a apparatus for rotating the rotor about its axis is added to the apparatus.

Simulator certification methods and the vertical motion simulator

NASA Technical Reports Server (NTRS)

Showalter, T. W.

1981-01-01

The vertical motion simulator (VMS) is designed to simulate a variety of experimental helicopter and STOL/VTOL aircraft as well as other kinds of aircraft with special pitch and Z axis characteristics. The VMS includes a large motion base with extensive vertical and lateral travel capabilities, a computer generated image visual system, and a high speed CDC 7600 computer system, which performs aero model calculations. Guidelines on how to measure and evaluate VMS performance were developed. A survey of simulation users was conducted to ascertain they evaluated and certified simulators for use. The results are presented.

The relation of motion sickness to the spatial-temporal properties of velocity storage

NASA Technical Reports Server (NTRS)

Dai, Mingjia; Kunin, Mikhail; Raphan, Theodore; Cohen, Bernard; Young, L. R. (Principal Investigator)

2003-01-01

Tilting the head in roll to or from the upright while rotating at a constant velocity (roll while rotating, RWR) alters the position of the semicircular canals relative to the axis of rotation. This produces vertical and horizontal nystagmus, disorientation, vertigo, and nausea. With recurrent exposure, subjects habituate and can make more head movements before experiencing overpowering motion sickness. We questioned whether promethazine lessened the vertigo or delayed the habituation, whether habituation of the vertigo was related to the central vestibular time constant, i.e., to the time constant of velocity storage, and whether the severity of the motion sickness was related to deviation of the axis of eye velocity from gravity. Sixteen subjects received promethazine and placebo in a double-blind, crossover study in two consecutive 4-day test series 1 month apart, termed series I and II. Horizontal and vertical eye movements were recorded with video-oculography while subjects performed roll head movements of approx. 45 degrees over 2 s to and from the upright position while being rotated at 138 degrees /s around a vertical axis. Motion sickness was scaled from 1 (no sickness) to an endpoint of 20, at which time the subject was too sick to continue or was about to vomit. Habituation was determined by the number of head movements that subjects made before reaching the maximum motion sickness score of 20. Head movements increased steadily in each session with repeated testing, and there was no difference between the number of head movements made by the promethazine and placebo groups. Horizontal and vertical angular vestibulo-ocular reflex (aVOR) time constants declined in each test, with the declines being closely correlated to the increase in the number of head movements. The strength of vertiginous sensation was associated with the amount of deviation of the axis of eye velocity from gravity; the larger the deviation of the eye velocity axis from gravity, the more severe the motion sickness. Thus, promethazine neither reduced the nausea associated with RWR, nor retarded or hastened habituation. The inverse relationship between the aVOR time constants and number of head movements to motion sickness, and the association of the severity of motion sickness with the extent, strength, and time of deviation of eye velocity from gravity supports the postulate that the spatiotemporal properties of velocity storage, which are processed between the nodulus and uvula of the vestibulocerebellum and the vestibular nuclei, are likely to represent the source of the conflict responsible for producing motion sickness.

Optokinetic and vestibular stimulation determines the spatial orientation of negative optokinetic afternystagmus in the rabbit.

PubMed

Pettorossi, V E; Errico, P; Ferraresi, A; Barmack, N H

1999-02-15

Prolonged binocular optokinetic stimulation (OKS) in the rabbit induces a high-velocity negative optokinetic afternystagmus (OKAN II) that persists for several hours. We have taken advantage of this uniform nystagmus to study how changes in static head orientation in the pitch plane might influence the orientation of the nystagmus. After horizontal OKS, the rotation axis of the OKAN II remained almost constant in space as it was kept aligned with the gravity vector when the head was pitched by as much as 80 degrees up and 35 degrees down. Moreover, during reorientation, slow-phase eye velocity decreased according to the head pitch angle. Thereafter, we analyzed the space orientation of OKAN II after optokinetic stimulation during which the head and/or the OKS were pitched upward and downward. The rotation axis of OKAN II did not remain aligned with an earth vertical axis nor a head vertical axis, but it tended to be aligned with that of the OKS respace. The slow-phase eye velocity of OKAN II was also affected by the head pitch angle during OKS, because maximal OKAN II velocity occurred at the same head pitch angle as that during optokinetic stimulation. We suggest that OKAN II is coded in gravity-centered rather than in head-centered coordinates, but that this coordinate system may be influenced by optokinetic and vestibular stimulation. Moreover, the velocity attenuation of OKAN II seems to depend on the mismatch between the space-centered nystagmus rotation axis orientation and that of the "remembered" head-centered optokinetic pathway activated by OKS.

Modulation of vergence by off-vertical yaw axis rotation in the monkey: normal characteristics and effects of space flight

NASA Technical Reports Server (NTRS)

Dai, M.; Raphan, T.; Kozlovskaya, I.; Cohen, B.

1996-01-01

Horizontal movements of both eyes were recorded simultaneously using scleral search coils in 2 rhesus monkeys before and after the COSMOS 2229 space-flight of 1992-1993. Another 9 monkeys were tested at comparable time intervals and served as controls. Ocular vergence, defined as the difference in horizontal position between the left and right eyes, was measured during off-vertical yaw axis rotation (OVAR) in darkness. Vergence was modulated sinusoidally as a function of head position with regard to gravity during OVAR. The amplitude of peak-to-peak modulation increased with increments in tilt of the angle of the rotational axis (OVAR tilt angle) that ranged from 15 degrees to 90 degrees. Of the 11 monkeys tested, 1 had no measurable modulation in vergence. In the other 10, the mean amplitude of the peak to peak modulation was 5.5 degrees +/- 1.3 degrees at 90 degrees tilt. Each of these monkeys had maximal vergence when its nose was pointed close to upward (gravity back; mean phase: -0.9 degree +/- 26 degrees). After space flight, the modulation in vergence was reduced by over 50% for the two flight monkeys, but the phase of vergence modulation was not altered. The reduction in vergence modulation was sustained for the 11-day postflight testing period. We conclude that changes in vergence are induced in monkeys by the sinusoidal component of gravity acting along the naso-occipital axis during yaw axis OVAR, and that the modulation of the vergence reflex is significantly less sensitive to linear acceleration after space flight.

Pilot-in-the-Loop CFD Method Development

DTIC Science & Technology

2015-02-01

expensive alternatives [1]. ALM represents the blades as a set of segments along with each blade axis and the ADM represents the entire rotor as...fine grid, Δx = 1.00 m Figure 4 – Time-averaged vertical velocity distributions on downwash and rotor disk plane for hybrid and loose coupling...cases with fine and coarse grid refinement levels. Figure 4 shows the time-averaged distributions of vertical velocities on both downwash and rotor disk

Why does a spinning egg rise?

NASA Astrophysics Data System (ADS)

Cross, Rod

2018-03-01

Experimental and theoretical results are presented concerning the rise of a spinning egg. It was found that an egg rises quickly while it is sliding and then more slowly when it starts rolling. The angular momentum of the egg projected in the XZ plane changed in the same direction as the friction torque, as expected, by rotating away from the vertical Z axis. The latter result does not explain the rise. However, an even larger effect arises from the Y component of the angular momentum vector. As the egg rises, the egg rotates about the Y axis, an effect that is closely analogous to rotation of the egg about the Z axis. Both effects can be described in terms of precession about the respective axes. Steady precession about the Z axis arises from the normal reaction force in the Z direction, while precession about the Y axis arises from the friction force in the Y direction. Precession about the Z axis ceases if the normal reaction force decreases to zero, and precession about the Y axis ceases if the friction force decreases to zero.

High-efficiency wind turbine

NASA Technical Reports Server (NTRS)

Hein, L. A.; Myers, W. N.

1980-01-01

Vertical axis wind turbine incorporates several unique features to extract more energy from wind increasing efficiency 20% over conventional propeller driven units. System also features devices that utilize solar energy or chimney effluents during periods of no wind.

Interferometric rotation sensor

NASA Technical Reports Server (NTRS)

Walsh, T. M.

1972-01-01

Sensor generates interference fringes varying in number (horizontally and vertically) as a function of the total angular deviation relative to the line-of-sight axis. Device eliminates errors from zero or null shift due to lack of electrical circuitry stability.

Large Wind Turbine Design Characteristics and R and D Requirements

NASA Technical Reports Server (NTRS)

Lieblein, S. (Editor)

1979-01-01

Detailed technical presentations on large wind turbine research and development activities sponsored by public and private organizations are presented. Both horizontal and vertical axis machines are considered with emphasis on their structural design.

GulfNEWS, Volume 3, Issue 4, July/August 1999

DTIC Science & Technology

1999-08-01

prevent injury and death, the detector had to be able to detect chemical agents in concentrations lower than those that would injure service members...and a six-month absence, Windmiller returned to his job. Keeping with his promise, he continues with that regimen of jogging and weightlifting

Analysis of off-grid hybrid wind turbine/solar PV water pumping systems

USDA-ARS?s Scientific Manuscript database

While many remote water pumping systems exist (e.g. mechanical windmills, solar photovoltaic , wind-electric, diesel powered), very few combine both the wind and solar energy resources to possibly improve the reliability and the performance of the system. In this paper, off-grid wind turbine (WT) a...

Large-Scale Implementation of Formative Assessment Practices in an Examination-Oriented Culture

ERIC Educational Resources Information Center

Ratnam-Lim, Christina Tong Li; Tan, Kelvin Heng Kiat

2015-01-01

Singapore's education system has often been characterised as exam-oriented. This paper describes efforts ("windmills") made by the Government to constructively respond to the "winds of change" in the education system. A committee called the Primary Education Review and Implementation (PERI) Committee was appointed to study and…

The orientation of the cervical vertebral column in unrestrained awake animals. I. Resting position.

PubMed

Vidal, P P; Graf, W; Berthoz, A

1986-01-01

The orientation of the cervical vertebral column was studied by X-ray photography of the region containing the head and the neck in nine unrestrained species of vertebrates (man, monkey, cat, rabbit, guinea pig, rat, chicken, frog, lizard). In addition, the orientation of the horizontal semicircular canals was measured in four species using landmarks on the skull. In all vertebrates studied, with the exception of frog and lizard, the general orientation of the cervical vertebral column was vertical when animals were at rest, and not horizontal or oblique as suggested by the macroscopic appearance of the neck. The posture of the animal, whether lying, sitting or standing, had little effect on this general vertical orientation, although some variability was noticed depending on the species. This finding prompted the definition of a resting zone, where the cervical column can take any orientation within a narrow range around a mean position. The cervical vertebral column composes part of the S-shaped structure of the entire vertebral column, with one inflection around the cervico-thoracic (C7/Th1) junction. This feature is already noticable in the lizard. The vertical orientation of the cervical vertebral column is interpreted to provide a stable and energy saving balance of the head. Furthermore, when the head is lowered or raised, the atlanto-occipital and cervico-thoracic junctions are predominantly involved, while the entire cervical column largely preserves its intrinsic configuration. The curved configuration of the cervico-thoracic vertebral column embedded in long spring-like muscles is interpreted to function as a shock absorber. At rest, animals did not hold their heads with the horizontal canals oriented earth horizontally all the time, but often maintained them pitched up by ca. 5 deg, as has been reported for man. At other times, presumably when the vigilance level increased, the horizontal canals were brought into the earth horizontal plane. The vertical orientation of the cervical column results in a vertical positioning of the odontoid process of the axis (second cervical vertebra, C2), which thus provides the axis of rotation for yaw movements of the head. This axis corresponds to that of the horizontal semicircular canals. The vertical organization of the cervical vertebral column in birds and mammals, whether the animal is quadrupedal or bipedal, points to a common organizational principle for eye and head movement systems.(ABSTRACT TRUNCATED AT 400 WORDS)

A numerical analysis to evaluate Betz's Law for vertical axis wind turbines

NASA Astrophysics Data System (ADS)

Thönnißen, F.; Marnett, M.; Roidl, B.; Schröder, W.

2016-09-01

The upper limit for the energy conversion rate of horizontal axis wind turbines (HAWT) is known as the Betz limit. Often this limit is also applied to vertical axis wind turbines (VAWT). However, a literature review reveals that early analytical and recent numerical approaches predicted values for the maximum power output of VAWTs close to or even higher than the Betz limit. Thus, it can be questioned whether the application of Betz's Law to VAWTs is justified. To answer this question, the current approach combines a free vortex model with a 2D inviscid panel code to represent the flow field of a generic VAWT. To ensure the validity of the model, an active blade pitch control system is used to avoid flow separation. An optimal pitch curve avoiding flow separation is determined for one specific turbine configuration by applying an evolutionary algorithm. The analysis yields a net power output that is slightly (≈6%) above the Betz limit. Besides the numerical result of an increased energy conversion rate, especially the identification of two physical power increasing mechanisms shows, that the application of Betz's Law to VAWTs is not justified.

Fish schooling as a basis for vertical axis wind turbine farm design.

PubMed

Whittlesey, Robert W; Liska, Sebastian; Dabiri, John O

2010-09-01

Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighboring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely spaced VAWTs may experience only small decreases (or even increases) in an individual turbine's power coefficient when placed in close proximity to neighbors, thus yielding much higher power outputs for a given area of land. A potential flow model of inter-VAWT interactions is developed to investigate the effect of changes in VAWT spatial arrangement on the array performance coefficient, which compares the expected average power coefficient of turbines in an array to a spatially isolated turbine. A geometric arrangement based on the configuration of shed vortices in the wake of schooling fish is shown to significantly increase the array performance coefficient based upon an array of 16 x 16 wind turbines. The results suggest increases in power output of over one order of magnitude for a given area of land as compared to HAWTs.

Wind tunnel study of a vertical axis wind turbine in a turbulent boundary layer flow

NASA Astrophysics Data System (ADS)

Rolin, Vincent; Porté-Agel, Fernando

2015-04-01

Vertical axis wind turbines (VAWTs) are in a relatively infant state of development when compared to their cousins the horizontal axis wind turbines. Very few studies have been carried out to characterize the wake flow behind VAWTs, and virtually none to observe the influence of the atmospheric boundary layer. Here we present results from an experiment carried out at the EPFL-WIRE boundary-layer wind tunnel and designed to study the interaction between a turbulent boundary layer flow and a VAWT. Specifically we use stereoscopic particle image velocimetry to observe and quantify the influence of the boundary layer flow on the wake generated by a VAWT, as well as the effect the VAWT has on the boundary layer flow profile downstream. We find that the wake behind the VAWT is strongly asymmetric, due to the varying aerodynamic forces on the blades as they change their position around the rotor. We also find that the wake adds strong turbulence levels to the flow, particularly on the periphery of the wake where vortices and strong velocity gradients are present. The boundary layer is also shown to cause greater momentum to be entrained downwards rather than upwards into the wake.

A 20-KW Wind Energy Conversion System (WECS) at the Marine Corps Air Station, Kaneohe, Hawaii.

DTIC Science & Technology

1983-01-01

of propellers and that vertical-axis wind turbines would be more efficient. Several turbines such as the Darrieus and gyro-mill, of this type are... wind turbines , wind systems siting, alternate energy systems, remote site power generation. 20 ABSTRACT (Con!,,u,. - r r... .. do I(3 lI - d #,d e...Corps Air Station (MCAS) Kaneohe Bay, Hawaii. The wind turbine generator chosen for the evaluation was a horizontal-axis-propeller- downwind rotor

Power optimal single-axis articulating strategies

NASA Technical Reports Server (NTRS)

Kumar, Renjith R.; Heck, Michael L.

1991-01-01

Power optimal single axis articulating PV array motion for Space Station Freedom is investigated. The motivation is to eliminate one of the articular joints to reduce Station costs. Optimal (maximum power) Beta tracking is addressed for local vertical local horizontal (LVLH) and non-LVLH attitudes. Effects of intra-array shadowing are also presented. Maximum power availability while Beta tracking is compared to full sun tracking and optimal alpha tracking. The results are quantified in orbital and yearly minimum, maximum, and average values of power availability.

Test results of the DOE/Sandia 17 meter VAWT

NASA Technical Reports Server (NTRS)

Nellums, R. O.; Worstell, M. H.

1979-01-01

A review is given of the test program of a 17 meter Vertical Axis Wind Turbine VAWT. Performance test results are discussed including difficulties encountered during the VAWT operation along with ways of solving these problems.

Design and fabrication of a low cost Darrieus vertical axis wind turbine system: Phase 2, volume 1: Executive summary

NASA Astrophysics Data System (ADS)

1983-03-01

Described is the successful fabrication, installation, and checkout of 100 kW 17 meter Vertical Axis Wind Turbines (VAWTs). The turbines are Darrieus-type VAWTs with rotors 17 meters (55 feet) in diameter and 25.15 meters (83 feet) in height. They can produce 100 kW of electric power at a cost of energy as low as 3 cents per kWh, in an 18 mph wind regime using 12% annualized costs. Four turbines were produced; three are installed and are operable at: (1) Wind Systems Test Center, Rocky Flats, Colorado; (2) the US Department of Agriculture Conservation and Production Research Center at Bushland, Texas; and (3) Tisbury Water Authority, Vineyard Haven, Massachusetts, on the island of Martha's Vineyard. The fourth turbine is stored at Bushland, Texas awaiting selection of an erection site.

The Oregon State University wind studies. [economic feasibility of windpowered generators

NASA Technical Reports Server (NTRS)

Wilson, R. E.

1973-01-01

The economic feasibility of commercial use of wind generated power in selected areas of Oregon is assessed. A number of machines for generating power have been examined. These include the Savonius rotor, translators, conventional wind turbines, the circulation controlled rotor and the vertical axis winged turbine. Of these machines, the conventional wind turbine and the vertical axis winged turbine show the greatest promise on the basis of the power developed per unit of rotor blade area. Attention has been focused on the structural and fatigue analysis of rotors since the economics of rotary winged, wind generated power depends upon low cost, long lifetime rotors. Analysis of energy storage systems and tower design has also been undertaken. An economic means of energy storage has not been found to date. Tower design studies have produced cost estimates that are in general agreement with the cost of the updated Putnam 110-foot tower.

Aerodynamic Interactions between Pairs of Vertical-Axis Wind Turbines

NASA Astrophysics Data System (ADS)

Brownstein, Ian; Dabiri, John

2017-11-01

Increased power production has been observed in downstream vertical-axis wind turbines (VAWTs) when positioned offset from the wake of upstream turbines. This effect was found to exist in both laboratory and field environments with pairs of co- and counter-rotating turbines. It is hypothesized that the observed power production enhancement is due to flow acceleration adjacent to the upstream turbine caused by bluff body blockage, which increases the incident freestream velocity on appropriately positioned downstream turbines. This type of flow acceleration has been observed in computational and laboratory studies of VAWTs and will be further investigated here using 3D-PTV measurements around pairs of laboratory-scale VAWTs. These measurements will be used to understand the mechanisms behind the performance enhancement effect and seek to determine optimal separation distances and angles between turbines based on turbine design parameters. These results will lead to recommendations for optimizing the power production of VAWT wind farms which utilize this effect.

Aerodynamic performance of a small vertical axis wind turbine using an overset grid method

NASA Astrophysics Data System (ADS)

Bangga, Galih; Solichin, Mochammad; Daman, Aida; Sa'adiyah, Devy; Dessoky, Amgad; Lutz, Thorsten

2017-08-01

The present paper aims to asses the aerodynamic performance of a small vertical axis wind turbine operating at a small wind speed of 5 m/s for 6 different tip speed ratios (λ=2-7). The turbine consists of two blades constructed using the NACA 0015 airfoil. The study is carried out using computational fluid dynamics (CFD) methods employing an overset grid approach. The (URANS) SST k - ω is used as the turbulence model. For the preliminary study, simulations of the NACA 0015 under static conditions for a broad range of angle of attack and a rotating two-bladed VAWT are carried out. The results are compared with available measurement data and a good agreement is obtained. The simulations demonstrate that the maximum power coefficient attained is 0.45 for λ=4. The aerodynamic loads hysteresis are presented showing that the dynamic stall effect decreases with λ.

Location of aerodynamic noise sources from a 200 kW vertical-axis wind turbine

NASA Astrophysics Data System (ADS)

Ottermo, Fredric; Möllerström, Erik; Nordborg, Anders; Hylander, Jonny; Bernhoff, Hans

2017-07-01

Noise levels emitted from a 200 kW H-rotor vertical-axis wind turbine have been measured using a microphone array at four different positions, each at a hub-height distance from the tower. The microphone array, comprising 48 microphones in a spiral pattern, allows for directional mapping of the noise sources in the range of 500 Hz to 4 kHz. The produced images indicate that most of the noise is generated in a narrow azimuth-angle range, compatible with the location where increased turbulence is known to be present in the flow, as a result of the previous passage of a blade and its support arms. It is also shown that a semi-empirical model for inflow-turbulence noise seems to produce noise levels of the correct order of magnitude, based on the amount of turbulence that could be expected from power extraction considerations.

Vortex Particle-Mesh simulations of Vertical Axis Wind Turbine flows: from the blade aerodynamics to the very far wake

NASA Astrophysics Data System (ADS)

Chatelain, P.; Duponcheel, M.; Caprace, D.-G.; Marichal, Y.; Winckelmans, G.

2016-09-01

A Vortex Particle-Mesh (VPM) method with immersed lifting lines has been developed and validated. Based on the vorticity-velocity formulation of the Navier-Stokes equations, it combines the advantages of a particle method and of a mesh-based approach. The immersed lifting lines handle the creation of vorticity from the blade elements and its early development. LES of Vertical Axis Wind Turbine (VAWT) flows are performed. The complex wake development is captured in details and over very long distances: from the blades to the near wake coherent vortices, then through the transitional ones to the fully developed turbulent far wake (beyond 10 rotor diameters). The statistics and topology of the mean flow are studied. The computational sizes also allow insights into the detailed unsteady vortex dynamics, including some unexpected topological flow features.

Increased Sensitivity to Mirror Symmetry in Autism

PubMed Central

Perreault, Audrey; Gurnsey, Rick; Dawson, Michelle; Mottron, Laurent; Bertone, Armando

2011-01-01

Can autistic people see the forest for the trees? Ongoing uncertainty about the integrity and role of global processing in autism gives special importance to the question of how autistic individuals group local stimulus attributes into meaningful spatial patterns. We investigated visual grouping in autism by measuring sensitivity to mirror symmetry, a highly-salient perceptual image attribute preceding object recognition. Autistic and non-autistic individuals were asked to detect mirror symmetry oriented along vertical, oblique, and horizontal axes. Both groups performed best when the axis was vertical, but across all randomly-presented axis orientations, autistics were significantly more sensitive to symmetry than non-autistics. We suggest that under some circumstances, autistic individuals can take advantage of parallel access to local and global information. In other words, autistics may sometimes see the forest and the trees, and may therefore extract from noisy environments genuine regularities which elude non-autistic observers. PMID:21559337

Human vertical eye movement responses to earth horizontal pitch

NASA Technical Reports Server (NTRS)

Wall, C. 3rd; Petropoulos, A. E.

1993-01-01

The vertical eye movements in humans produced in response to head-over-heels constant velocity pitch rotation about a horizontal axis resemble those from other species. At 60 degrees/s these are persistent and tend to have non-reversing slow components that are compensatory to the direction of rotation. In most, but not all subjects, the slow component velocity was well characterized by a rapid build-up followed by an exponential decay to a non-zero baseline. Super-imposed was a cyclic or modulation component whose frequency corresponded to the time for one revolution and whose maximum amplitude occurred during a specific head orientation. All response components (exponential decay, baseline and modulation) were larger during pitch backward compared to pitch forward runs. Decay time constants were shorter during the backward runs, thus, unlike left to right yaw axis rotation, pitch responses display significant asymmetries between paired forward and backward runs.

Performance testing of a 50 kW VAWT in a built-up environment

NASA Technical Reports Server (NTRS)

Schienbein, L. A.

1981-01-01

The results of performance tests of a DAF Indal 50 kW vertical axis wind turbine are presented. Results of limited free stream turbulence and vertical wind shear measurements at the site are also presented. The close agreement between measured and predicted energy outputs, required to verify the wind turbine power output performance relationship, was not attained. A discussion is presented of factors that may have contributed to the lack of better agreement.

Focusing Light Rays Back to the Vertex of a Reflecting Parabolic Collector: The Equivalent of Dionysius Ear Effect in Optical Systems

ERIC Educational Resources Information Center

De Luca, R.; Fedullo, A.

2009-01-01

A vertical light ray coming from infinity is reflected by a primary parabolic mirror M[subscript 1] having focus at F[subscript 1]. At a small distance from F[subscript 1] a secondary mirror M[subscript 2], symmetric with respect to the vertical axis, is placed. One would like to find the analytic equation of the mirror M[subscript 2], so that all…

Effects of Froude number and geometry on water entry of a 2-D ellipse

NASA Astrophysics Data System (ADS)

Zhang, Xu; Liu, Pei-qing; Qu, Qiu-lin; Wang, Rui; Agarwal, Ramesh K.

2018-05-01

By using the finite volume method with volume of fluid model and global dynamic mesh technique, the effects of Froude number and geometry on the water entry process of a 2-D ellipse are investigated numerically. For the time history of the vertical force, the computational fluid dynamics (CFD) results match the experimental data much better than the classical potential-flow theories due to the consideration of the viscosity, turbulence, surface tension, gravity, and compressibility. The results show that the position of peak pressure on ellipse shifts from the spray root to the bottom of ellipse at a critical time. The critical time changes with the geometry and Froude number. By studying the vertical force, the ellipse water entry process can be divided into the initial and late stages based on the critical dimensionless time of about 0.1. The geometry of the ellipse plays a dominant role in the initial stage, while the Froude number is more important in the late stage of entry. The classical Wagner theory is extended to the ellipse water entry, and the predicted maximum value of vertical force coefficient in the initial stage is 4πa/b that matches the CFD results very well, where a and b are the horizontal axis and vertical axis of the ellipse parallel and perpendicular to the initial calm water surface, respectively.

Ocular and perceptual responses to linear acceleration in microgravity: alterations in otolith function on the COSMOS and Neurolab flights.

PubMed

Moore, Steven T; Clément, Gilles; Dai, Mingjai; Raphan, Theodore; Solomon, David; Cohen, Bernard

2003-01-01

In this paper we review space flight experiments performed by our laboratory. Rhesus monkeys were tested before and after 12 days in orbit on COSMOS flights 2044 (1989) and 2229 (1992-1993). There was a long-lasting decrease in post-flight ocular counter-rolling (70%) and vergence (50%) during off-vertical axis rotation. In one animal, the orientation of optokinetic after-nystagmus shifted by 28 degrees from the spatial vertical towards the body vertical early post-flight. Otolith-ocular and perceptual responses were also studied in four astronauts on the 17-day Neurolab shuttle mission (STS-90) in 1998. Ocular counter-rolling was unchanged in response to 1-g and 0.5-g Gy centrifugation during and after flight and to post-flight static roll tilts relative to pre-flight values. Orientation of the optokinetic nystagmus eye velocity axis to gravito-inertial acceleration (GIA) during centrifugation was also unaltered by exposure to microgravity. Perceptual orientation to the GIA was maintained in-flight, and subjects did not report sensation of translation during constant velocity centrifugation. These studies suggest that percepts and ocular responses to tilt are determined by sensing the body vertical relative to the GIA. The findings also raise the possibility that 'artificial gravity' during the Neurolab flight counteracted adaptation of these otolith-ocular responses.

Wind turbine spoiler

DOEpatents

Sullivan, W.N.

An aerodynamic spoiler system for a vertical axis wind turbine includes spoilers on the blades initially stored near the rotor axis to minimize drag. A solenoid latch adjacent the central support tower releases the spoilers and centrifugal force causes the spoilers to move up the turbine blades away from the rotor axis, thereby producing a braking effect and actual slowing of the associated wind turbine, if desired. The spoiler system can also be used as an infinitely variable power control by regulated movement of the spoilers on the blades over the range between the undeployed and fully deployed positions. This is done by the use of a suitable powered reel and cable located at the rotor tower to move the spoilers.

Wind turbine spoiler

DOEpatents

Sullivan, William N.

1985-01-01

An aerodynamic spoiler system for a vertical axis wind turbine includes spoilers on the blades initially stored near the rotor axis to minimize drag. A solenoid latch adjacent the central support tower releases the spoilers and centrifugal force causes the spoilers to move up the turbine blades away from the rotor axis, thereby producing a braking effect and actual slowing of the associated wind turbine, if desired. The spoiler system can also be used as an infinitely variable power control by regulated movement of the spoilers on the blades over the range between the undeployed and fully deployed positions. This is done by the use of a suitable powered reel and cable located at the rotor tower to move the spoilers.

Tectonic reconstruction of the Panama arc using paleomagnetic, geochronology and thermochronologic data

NASA Astrophysics Data System (ADS)

Montes, C.; Bayona, G.; Cardona, A.; Pardo, A.; Nova, G.; Montano, P.

2013-05-01

A recent update of the geochronologic and mapping database of the Isthmus of Panama suggests that the Isthmus represents an arc that was left-laterally fragmented between 38 and 28 Ma, and then oroclinally bent. This was hypothesis was tested using paleomagnetic data (24 sites and 192 cores) that indicated large counterclockwise vertical-axis rotations (70.9°, ± 6.7°), and moderate clockwise rotations (between 40° ± 4.1° and 56.2° ± 11.1) on either side of an east-west trending fault at the apex of the Isthmus (Rio Gatun Fault), consistent with Isthmus curvature. Sampling for paleomagnetism was performed on Cretaceous basaltic rocks of the Panama arc, some of them probably correlative to the Caribbean large igneous province. Also, sampling took place in younger Cenozoic cover rocks, as well as in the younger arc rocks. This database is here complemented with 15 new pilot paleomagnetic sites taken in eastern, central, and western Panama, and 3 new sites from Miocene cover rocks of what is now considered to be the southeastern-most tip of the Central American arc. The latter record clockwise vertical-axis rotations between 12 and 40°, in agreement with oroclinal bending hypothesis for the formation of the Isthmus of Panama. These new results begin to fill a gap in the paleomagnetic vertical-axis rotation database for the Panama arc. These results also support the continuity of the Central America arc to the east, into what is now docked to western South America.

Bearing construction for refrigeration compresssor

DOEpatents

Middleton, Marc G.; Nelson, Richard T.

1988-01-01

A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

Effective solidity in vertical axis wind turbines

NASA Astrophysics Data System (ADS)

Parker, Colin M.; Leftwich, Megan C.

2016-11-01

The flow surrounding vertical axis wind turbines (VAWTs) is investigated using particle imaging velocimetry (PIV). This is done in a low-speed wind tunnel with a scale model that closely matches geometric and dynamic properties tip-speed ratio and Reynolds number of a full size turbine. Previous results have shown a strong dependance on the tip-speed ratio on the wake structure of the spinning turbine. However, it is not clear whether this is a speed or solidity effect. To determine this, we have measured the wakes of three turbines with different chord-to-diameter ratios, and a solid cylinder. The flow is visualized at the horizontal mid-plane as well as the vertical mid-plane behind the turbine. The results are both ensemble averaged and phase averaged by syncing the PIV system with the rotation of the turbine. By keeping the Reynolds number constant with both chord and diameter, we can determine how each effects the wake structure. As these parameters are varied there are distinct changes in the mean flow of the wake. Additionally, by looking at the vorticity in the phase averaged profiles we can see structural changes to the overall wake pattern.

Effects of mechanostimulation on gravitropism and signal persistence in flax roots.

PubMed

John, Susan P; Hasenstein, Karl H

2011-09-01

Gravitropism describes curvature of plants in response to gravity or differential acceleration and clinorotation is commonly used to compensate unilateral effect of gravity. We report on experiments that examine the persistence of the gravity signal and separate mechanostimulation from gravistimulation. Flax roots were reoriented (placed horizontally for 5, 10 or 15 min) and clinorotated at a rate of 0.5 to 5 rpm either vertically (parallel to the gravity vector and root axis) or horizontally (perpendicular to the gravity vector and parallel to the root axis). Image sequences showed that horizontal clinorotation did not affect root growth rate (0.81 ± 0.03 mm h-1) but vertical clinorotation reduced root growth by about 7%. The angular velocity (speed of clinorotation) did not affect growth for either direction. However, maximal curvature for vertical clinorotation decreased with increasing rate of rotation and produced straight roots at 5 rpm. In contrast, horizontal clinorotation increased curvature with increasing angular velocity. The point of maximal curvature was used to determine the longevity (memory) of the gravity signal, which lasted about 120 min. The data indicate that mechanostimulation modifies the magnitude of the graviresponse but does not affect memory persistence.

Three-dimensional force measurements with mandibular overdentures connected to implants by ball-shaped retentive anchors. A clinical study.

PubMed

Mericske-Stern, R

1998-01-01

The purpose of this in vivo study was to determine maximum and functional forces simultaneously in three dimensions on mandibular implants supporting overdentures. The anchorage system for overdenture connection was the ball-shaped retentive anchor. Five edentulous patients, each with two mandibular ITI implants, were selected as test subjects. A novel miniaturized piezo-electric force transducer was developed for specific use with ITI implants. Force magnitudes and directions were registered under various test conditions by means of electrostatic plotter records. The test modalities were maximum biting in centric occlusion, maximum biting on a bite plate, grinding, and chewing bread. Maximum forces measured in centric occlusion and on the ipsilateral implant when using a bite plate were slightly increased in vertical and backward-forward dimension (z-, y-axis) compared to the lateral-medial direction (x-axis). On the contralateral implant, equally low values were found in all three dimensions. This may be the effect of a nonsplinted anchorage device. With the use of a bite plate, force magnitudes on the ipsilateral implant were significantly higher on the z- and y-axis than mean maximum forces in centric occlusion (P < .001). Chewing and grinding resulted in lower forces compared to maximum biting, particularly in the vertical direction. The transverse force component in backward-forward direction, however, reached magnitudes that exceeded the vertical component by 100% to 300% during chewing function. This chewing pattern had not been observed in previous investigations with bars and telescopes, and therefore appears to be specific for retentive ball anchors. The prevalent or exclusive force direction registered on both implants in the vertical direction was downward under all test conditions. In the transverse direction during maximum biting the forward direction was more frequently registered, while no obvious prevalence of transverse force direction was observed during chewing and grinding.

Wind data from Memphis airport

DOT National Transportation Integrated Search

1997-06-01

A 1300-foot array of horizontal and vertical single-axis anemometers was installed at the Memphis, TN Airport on 10- and 13-foot poles under the approach to Runway 727. One-minute average measurements were recorded continuously from mid August 1995 t...

Design and performance characteristics of a mechanically driven vestibular stimulator.

DOT National Transportation Integrated Search

1964-01-01

In order to determine basic response characteristics of mammalian vestibular systems, the sytems so important for spatial orientation, a device to provide programs of controlled angular accelerations about the vertical axis was required. The small ro...

Testing a Windmill Airplane ("autogiro")

NASA Technical Reports Server (NTRS)

Seiferth, R

1927-01-01

In order to clear up the matter ( In the Spanish report it was stated that the reference surface for the calculation of the coefficients c(sub a) and c(sub w) was the area of all four wings, instead of a single wing), the model of a windwill airplane was tested in the Gottingen wind tunnel.

An Experiment on Wind Energy

ERIC Educational Resources Information Center

Lombardo, Vincenzo; Fiordilino, Emilio; Gallitto, Aurelio Agliolo; Aglieco, Pasquale

2012-01-01

We discuss an experiment on wind energy performed with home-made apparatus. The experiment reproduces a laboratory windmill, which can pump water from a lower level to a higher one. By measuring the gain of the gravitational potential energy of the pumped water, one can determine the power extracted from the wind. The activity was carried out with…

12. FLOOR 2; STONE CRANE IN PLACE FOR ROCK STONES; ...

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

12. FLOOR 2; STONE CRANE IN PLACE FOR ROCK STONES; STONE CRANE HAS OAK SPAR, JIB AND BRACE, METAL SCREW, IRON YOKE AND DOGS; IRON PINS FIT THROUGH HOLES IN DOGS INTO HOLES DRILLED IN RUNNER STONE - Hook Windmill, North Main Street at Pantigo Road, East Hampton, Suffolk County, NY

Sculpture, view looking to pair of lions, positioned at top ...

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

Sculpture, view looking to pair of lions, positioned at top of stairs leading down into the Glen from DeWitt Circle, just north of the American Bungalow (note: Windmill in background) - National Park Seminary, Bounded by Capitol Beltway (I-495), Linden Lane, Woodstove Avenue, & Smith Drive, Silver Spring, Montgomery County, MD

Study on Micro Wind Generator System for Automobile

NASA Astrophysics Data System (ADS)

Fujimoto, Koji; Washizu, Shinsuke; Ichikawa, Tomohiko; Yukita, Kazuto; Goto, Yasuyuki; Ichiyanagi, Katsuhiro; Oshima, Takamitsu; Hayashi, Niichi; Tobi, Nobuo

This paper proposes the micro wind generator system for automobile. This proposes system is composed of the deflector, the micro windmill, the generator, and electric storage device. Then, the effectiveness is confirmed from an examination using air blower. Therefore, new energy can be expected to be obtained by installing this system in the truck.

JSC SITE - BUILDINGS - JSC

NASA Image and Video Library

1962-01-01

S76-32986 (March 1962) --- A color enhancement of a black and white photograph of a water trough, windmill, grazing area and feed lot on the future site of the Manned Spacecraft Center, Houston, Texas. NOTE: The Manned Spacecraft Center was named Lyndon B. Johnson Space Center in memory of the late President following his death.

A Paleomagnetic Investigation of Large-Scale Vertical Axis Rotations in Coastal Sonora: Evidence for Transtensional Proto-Gulf Deformation

NASA Astrophysics Data System (ADS)

Herman, S. W.; Gans, P. B.

2006-12-01

A paleomagnetic investigation into possible vertical axis rotations has been conducted in the Sierra el Aguaje and Sierra Tinajas del Carmen, Sonora, Mexico, in order assess proposed styles for oblique continental rifting in the Gulf of California. Two styles of rifting have been proposed; (1) strain partitioning (Stock and Hodges, 89), and (2) transtension (Gans, 97), for the Proto-Gulf period of the Gulf of California. The presence of large- scale vertical axis rotations would lend weight to the argument for transtension. The Sierra el Aguaje and Sierra Tinajas del Carmen are located in southwestern coastal Sonora, Mexico. The ranges represent the eastern-rifted margin of the central Gulf of California. This is one of the few areas of that margin which is entirely above water, with new ocean crust of the Guaymas basin lying immediately offshore of the western edge of the ranges. The ranges are composed of volcanic units and their corresponding volcaniclastic units that are the result of persistent magmatic activity between 20 and 8.8 Ma, including three packages of basalt and andesite that make excellent paleomagnetic recorders. Based on cross cutting relations and geochronologic data for pre-, syn-, and post-tectonic volcanic units, most of the faulting and tilting in the Sierra El Aguaje and Sierra Tinajas del Carmen is bracketed between 11.9 and 9.0 Ma, thus falling entirely within Proto-Gulf time. Existing field relations suggest the presence of large (>45°) vertical axis rotations in this region. This evidence includes: a) abrupt changes in the strike of tilted strata in different parts of the range b) ubiquitous NE-SW striking faults with left lateral-normal oblique slip, that terminate against major NW-trending right lateral faults, and c) obliquity between the general strike of tilted strata and the strike of faults. The results of the paleomagnetic investigation are consistent with the field evidence and show large clockwise rotations between ~30° and ~100° with no discernable translation. Such large-scale rotations lend credence to the theory that the area inboard of Baja California was experiencing transtension during the Proto-Gulf period, rather than the pure extension that would have been the result of strain partitioning.

Paleomagnetism and Anisotropy of Magnetic Susceptibility study of the Miocene Jack Springs Tuff (Nevada, USA)

NASA Astrophysics Data System (ADS)

Shields, S.; Petronis, M. S.; Pluhar, C. J.; Gordon, L.

2014-12-01

The mid-Miocene Jack Springs Tuff (JST) outcrops across the western Mina Deflection accommodation zone, west-central Nevada and into eastern California. Previously, the source location for the JST was unknown, yet recent studies northwest of Mono Lake, CA have identified a relatively un-rotated structural block in which to reference the paleomagnetic data. Although new studies have indicated that this block may be rotated up to 13º, we argue that the probable source area is located near the Bodie Hills, CA. At this site, the paleomagnetic reference direction is D = 353°, I = 43°, α95 = 7.7° (Carlson et al, 2013). Based on these data, the JST can be used to measure absolute vertical-axis rotation as well as enable reconstruction of the paleo-topography using the corrected anisotropy of magnetic susceptibility (AMS) data. A total of 19 sites were sampled to constrain Cenozoic to recent vertical axis rotation within the region and AMS experiments were conducted to determine the flow direction of the JST. Curie point estimates indicate that the JST ranges in titanium concentration from 0.042 to 1.10, indicating a low to moderate titanomagnetite phase (Akimoto, 1962). Demagnetization experiments reveal mean destructive fields of the NRM ranging between 15mT and 40mT suggesting that both multi-domain to pseudo-single domain grains are the dominant ferromagnetic phases that carry the remanence and AMS fabric. Preliminary paleomagnetic data yield stable single component demagnetization behavior for most sites that, after structural correction, indicate clockwise vertical axis rotation ranging from +20°± 10° to +60°± 11° between multiple fault blocks. The uncorrected AMS data yield oblate magnetic fabrics that can be used to infer the transport direction, source region, and paleovalley geometry of the JST. These data are tentatively interpreted to indicate west to east transport of the JST across the Mono Basin region into the Mina Deflection that was erupted and flowed into a paleovalley off the Sierra Nevada Mountain front. Based on the new paleomagnetic data, we hypothesize that the JST experienced clockwise vertical axis rotation associated with transtensional faulting east of Mono Lake, CA. Our paleomagnetic data support this hypothesis and we argue that deformation likely occurred between ca. 9.5 Ma to as late as 3 Ma.

Tilted geostrophic convection in icy world oceans caused by the horizontal component of the planetary rotation vector

NASA Astrophysics Data System (ADS)

Goodman, J. C.

2012-12-01

The Coriolis force provides dominant control over the motion of atmospheres and oceans, both on Earth and on many other worlds. At any point on a planet's surface, the planetary rotation vector has both a vertical component and a horizontal (north-south) component. We typically ignore the horizontal component, which is justified if vertical motions are hydrostatic and the fluid is relatively shallow. Neither of these conditions is true for hydrothermal convection within the thick ocean layers of Europa and other icy worlds. Using the MITGCM ocean model, we explore the behavior of buoyant hydrothermal plumes in a deep unstratified ocean, including both components of the planetary rotation vector. We find that warm water does not rise vertically: instead, it spirals along the axis of planetary rotation. Eddies form which are tilted with respect to the local vertical, but parallel to the rotation axis: turbulent exchange of heat between these canted eddies carries the warm water toward the surface. This is not an entirely new idea: however, the implications for icy worlds have not been previously discussed. We observe that when these tilted plumes heat the ice layer above the ocean, the heating "footprint" of these tilted plumes will be more circular near the pole, more ellipsoidal in the tropics. If surface features of the ice crust were created by plume heating, their shapes ought to show consistent latitude trends. Also, we observe that if warm fluid were totally constrained to move along the planetary rotation axis, geothermal heat generated in the icy world's interior could never reach the ice crust near the equator. (For Europa, the "forbidden zone" could extend as far as +/- 20-25° latitude.) In practice, we find that turbulent eddies do allow heat to move perpendicular to the rotation vector, so the "forbidden zone" is not a tight constraint; still, it may affect the overall heating pattern of icy world crusts. Snapshot of ascent of buoyant hydrothermal plume in Europa's ocean (Seafloor heat source = 4 GW; ocean depth = 100 km; rotation period = 3.55 days; latitude = 30° N). Left: elevation section through plume. Right: 3-d isosurface of constant temperature (1 microkelvin above ambient). Note alignment of geostrophic eddies along angular rotation axis.

Effectiveness enhancement of a cycloidal wind turbine by individual active control of blade motion

NASA Astrophysics Data System (ADS)

Hwang, In Seong; Lee, Yun Han; Kim, Seung Jo

2007-04-01

In this paper, a research for the effectiveness enhancement of a Cycloidal Wind Turbine by individual active control of blade motion is described. To improve the performance of the power generation system, which consists of several straight blades rotating about axis in parallel direction, the cycloidal blade system and the individual active blade control method are adopted. It has advantages comparing with horizontal axis wind turbine or conventional vertical axis wind turbine because it maintains optimal blade pitch angles according to wind speed, wind direction and rotor rotating speed to produce high electric power at any conditions. It can do self-starting and shows good efficiency at low wind speed and complex wind condition. Optimal blade pitch angle paths are obtained through CFD analysis according to rotor rotating speed and wind speed. The individual rotor blade control system consists of sensors, actuators and microcontroller. To realize the actuating device, servo motors are installed to each rotor blade. Actuating speed and actuating force are calculated to compare with the capacities of servo motor, and some delays of blade pitch angles are corrected experimentally. Performance experiment is carried out by the wind blowing equipment and Labview system, and the rotor rotates from 50 to 100 rpm according to the electric load. From this research, it is concluded that developing new vertical axis wind turbine, Cycloidal Wind Turbine which is adopting individual active blade pitch control method can be a good model for small wind turbine in urban environment.

New airfoil sections for straight bladed turbine

NASA Astrophysics Data System (ADS)

Boumaza, B.

1987-07-01

A theoretical investigation of aerodynamic performance for vertical axis Darrieus wind turbine with new airfoils sections is carried out. The blade section aerodynamics characteristics are determined from turbomachines cascade model. The model is also adapted to the vertical Darrieus turbine for the performance prediction of the machine. In order to choose appropriate value of zero-lift-drag coefficient in calculation, an analytical expression is introduced as function of chord-radius ratio and Reynolds numbers. New airfoils sections are proposed and analyzed for straight-bladed turbine.

Overview of Vertical Axis Wind Turbine (VAWT)

NASA Technical Reports Server (NTRS)

Sullivan, W. N.

1979-01-01

A survey is presented of the practices which were applied for designing VAWT blades. An attempt is made to discuss strengths and weaknesses of the existing procedures. Discussion is provided on planned or suggested future work in developing improved design tools.

Motion of Optically Heated Spheres at the Water-Air Interface.

PubMed

Girot, A; Danné, N; Würger, A; Bickel, T; Ren, F; Loudet, J C; Pouligny, B

2016-03-22

A micrometer-sized spherical particle classically equilibrates at the water-air interface in partial wetting configuration, causing about no deformation to the interface. In condition of thermal equilibrium, the particle just undergoes faint Brownian motion, well visible under a microscope. We report experimental observations when the particle is made of a light-absorbing material and is heated up by a vertical laser beam. We show that, at small laser power, the particle is trapped in on-axis configuration, similarly to 2-dimensional trapping of a transparent sphere by optical forces. Conversely, on-axis trapping becomes unstable at higher power. The particle escapes off the laser axis and starts orbiting around the axis. We show that the laser-heated particle behaves as a microswimmer with velocities on the order of several 100 μm/s with just a few milliwatts of laser power.

Analytic studies of local-severe-storm observables by satellites

NASA Technical Reports Server (NTRS)

Dergarabedian, P.; Fendell, F.

1977-01-01

Attention is concentrated on the exceptionally violet whirlwind, often characterized by a fairly vertical axis of rotation. For a cylindrical polar coordinate system with axis coincident with the axis of rotation, the secondary flow involves the radial and axial velocity components. The thesis advanced is, first, that a violent whirlwind is characterized by swirl speeds relative to the axis of rotation on the order of 90 m/s, with 100 m/s being close to an upper bound. This estimate is based on interpretation of funnel-cloud shape (which also suggests properties of the radial profile of swirl, as well as the maximum magnitude); an error assessment of the funnel-cloud interpretation procedure is developed. Second, computation of ground-level pressure deficits achievable from typical tornado-spawning ambients by idealized thermohydrostatic processes suggests that a two-cell structure is required to sustain such large speeds.

Method of making a modular off-axis solar concentrator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plesniak, Adam P.; Hall, John C.

A method of making a solar concentrator may include forming a receiving wall having an elongated wall, a first side wall and a second side wall; attaching the first side wall and the second side wall to a reflecting wall to form a housing having an internal volume with an opening; forming a lip on the receiving wall and the reflecting wall; attaching a cover to the receiving wall and the reflecting wall at the lip to seal the opening into the internal volume, thereby creating a rigid structure; and mounting at least one receiver having at least one photovoltaicmore » cell on the elongated wall to receive solar radiation entering the housing and reflected by the receiving wall, the receiver having an axis parallel with a surface normal of the photovoltaic cell, such that the axis is disposed at a non-zero angle relative to the vertical axis of the opening.« less

Multivoxel Pattern Analysis Reveals 3D Place Information in the Human Hippocampus.

PubMed

Kim, Misun; Jeffery, Kate J; Maguire, Eleanor A

2017-04-19

The spatial world is three dimensional (3D) and humans and other animals move both horizontally and vertically within it. Extant neuroscientific studies have typically investigated spatial navigation on a horizontal 2D plane, leaving much unknown about how 3D spatial information is represented in the brain. Specifically, horizontal and vertical information may be encoded in the same or different neural structures with equal or unequal sensitivity. Here, we investigated these possibilities using fMRI while participants were passively moved within a 3D lattice structure as if riding a rollercoaster. Multivoxel pattern analysis was used to test for the existence of information relating to where and in which direction participants were heading in this virtual environment. Behaviorally, participants had similarly accurate memory for vertical and horizontal locations and the right anterior hippocampus (HC) expressed place information that was sensitive to changes along both horizontal and vertical axes. This is suggestive of isotropic 3D place encoding. In contrast, participants indicated their heading direction faster and more accurately when they were heading in a tilted-up or tilted-down direction. This direction information was expressed in the right retrosplenial cortex and posterior HC and was only sensitive to vertical pitch, which could reflect the importance of the vertical (gravity) axis as a reference frame. Overall, our findings extend previous knowledge of how we represent the spatial world and navigate within it by taking into account the important third dimension. SIGNIFICANCE STATEMENT The spatial world is 3D. We can move horizontally across surfaces, but also vertically, going up slopes or stairs. Little is known about how the brain supports representations of 3D space. A key question is whether horizontal and vertical information is equally well represented. Here, we measured fMRI response patterns while participants moved within a virtual 3D environment and found that the anterior hippocampus (HC) expressed location information that was sensitive to the vertical and horizontal axes. In contrast, information about heading direction, found in retrosplenial cortex and posterior HC, favored the vertical axis, perhaps due to gravity effects. These findings provide new insights into how we represent our spatial 3D world and navigate within it. Copyright © 2017 Kim et al.

Analysis of propulsion system dynamics in the validation of a high-order state space model of the UH-60

NASA Technical Reports Server (NTRS)

Kim, Frederick D.

1992-01-01

Frequency responses generated from a high-order linear model of the UH-60 Black Hawk have shown that the propulsion system influences significantly the vertical and yaw dynamics of the aircraft at frequencies important to high-bandwidth control law designs. The inclusion of the propulsion system comprises the latest step in the development of a high-order linear model of the UH-60 that models additionally the dynamics of the fuselage, rotor, and inflow. A complete validation study of the linear model is presented in the frequency domain for both on-axis and off-axis coupled responses in the hoverflight condition, and on-axis responses for forward speeds of 80 and 120 knots.

Rayleigh wave effects in an elastic half-space.

NASA Technical Reports Server (NTRS)

Aggarwal, H. R.

1972-01-01

Consideration of Rayleigh wave effects in a homogeneous isotropic linearly elastic half-space subject to an impulsive uniform disk pressure loading. An approximate formula is obtained for the Rayleigh wave effects. It is shown that the Rayleigh waves near the center of loading arise from the portion of the dilatational and shear waves moving toward the axis, after they originate at the edge of the load disk. A study is made of the vertical displacement due to Rayleigh waves at points on the axis near the surface of the elastic half-space.

Comparison of tropospheric NO2 vertical columns in an urban environment using satellite, multi-axis differential optical absorption spectroscopy, and in situ measurements

NASA Astrophysics Data System (ADS)

Mendolia, D.; D'Souza, R. J. C.; Evans, G. J.; Brook, J.

2013-10-01

Tropospheric NO2 vertical column densities have been retrieved and compared for the first time in Toronto, Canada, using three methods of differing spatial scales. Remotely sensed NO2 vertical column densities, retrieved from multi-axis differential optical absorption spectroscopy and satellite remote sensing, were evaluated by comparison with in situ vertical column densities estimated using a pair of chemiluminescence monitors situated 0.01 and 0.5 km a.g.l. (above ground level). The chemiluminescence measurements were corrected for the influence of NOz, which reduced the NO2 concentrations at 0.01 and 0.5 km by an average of 8 ± 1% and 12 ± 1%, respectively. The average absolute decrease in the chemiluminescence NO2 measurement as a result of this correction was less than 1 ppb. The monthly averaged ratio of the NO2 concentration at 0.5 to 0.01 km varied seasonally, and exhibited a negative linear dependence on the monthly average temperature, with Pearson's R = 0.83. During the coldest month, February, this ratio was 0.52 ± 0.04, while during the warmest month, July, this ratio was 0.34 ± 0.04, illustrating that NO2 is not well mixed within 0.5 km above ground level. Good correlation was observed between the remotely sensed and in situ NO2 vertical column densities (Pearson's R value ranging from 0.72 to 0.81), but the in situ vertical column densities were 52 to 58% greater than the remotely sensed columns. These results indicate that NO2 horizontal heterogeneity strongly impacted the magnitude of the remotely sensed columns. The in situ columns reflected an urban environment with major traffic sources, while the remotely sensed NO2 vertical column densities were representative of the region, which included spatial heterogeneity introduced by residential neighbourhoods and Lake Ontario. Despite the difference in absolute values, the reasonable correlation between the vertical column densities determined by three distinct methods increased confidence in the validity of the values provided by each measurement technique.

75 FR 70724 - Notice of Petitions by Firms for Determination of Eligibility To Apply for Trade Adjustment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-18

... designs and Chicago, IL 60642. manufactures industrial and commercial refrigeration equipment such as..., or threat thereof, and to a decrease in sales or production of each petitioning firm. List of... 4277 Dan Hanks Lane, San 10/29/2010 The firm manufactures of Angelo, TX 76902. windmills and the...

Mental Representation of Prepositional Compounds: Evidence from Italian Agrammatic Patients

ERIC Educational Resources Information Center

Mondini, S.; Luzzatti, C.; Saletta, P.; Allamano, N.; Semenza, C.

2005-01-01

The processing of Prepositional compounds (typical Neo-latin noun-noun modifications where a head noun is modified by a prepositional phrase, e.g., mulino a vento, windmill) was preliminarily studied with a group of six agrammatic aphasic patients, and, in more detail, with a further agrammatic patient (MB). Omission was the most frequent error…

Fields of Opportunity: Wind Machines Return to the Plains

ERIC Educational Resources Information Center

Sowers, Jacob

2006-01-01

The last two decades have seen a rebirth of wind machines on the rural landscape. In ironic fashion the wind's kinetic energy has grown in significance through its ability to generate commercial amounts of electricity, the commodity that a few generations earlier hastened the demise of the old Great Plains windmill. Yet the reemergence of wind…

From the Grassroots: Case Studies of Eight Rural Self-Development Efforts.

ERIC Educational Resources Information Center

Flora, Jan L.; And Others

Grassroots efforts were examined through a survey of 103 self-development projects across the United States, enriched by an indepth study of 8 successful and unsuccessful cases. They were as follows: Revolving Loan Fund, Mankato, Kansas; Orofino Unlimited, Orofino, Idaho; Center for Industry, Rome, Georgia; Windmill Market Farm and Craft Co-op,…

33 CFR 162.130 - Connecting waters from Lake Huron to Lake Erie; general rules.

Code of Federal Regulations, 2010 CFR

2010-07-01

... vessel astern, alongside, or by pushing ahead; and (iii) Each dredge and floating plant. (4) The traffic... towing another vessel astern, alongside or by pushing ahead; and (iv) Each dredge and floating plant. (c... Captain of the Port of Detroit, Michigan. Detroit River means the connecting waters from Windmill Point...

Grinding technoloy of aspheric molds for glass-molding; Technical Digest

NASA Astrophysics Data System (ADS)

Kojima, Yoichi

2005-05-01

We introduce the method of precisely grinding of axis-symmetric aspherical glass-molding dies by using a diamond wheel. Those show how to select vertical-grinding or slant-grinding, how to grind molds with high accuracy and actual grinding results.

Viscous-pendulum damper suppresses structural vibrations

NASA Technical Reports Server (NTRS)

Reed, W. H., III

1964-01-01

The viscous pendulum damper consists of a cylinder containing round trays on which round lead slugs rest. When assembled, the container is filled with a viscous liquid and attached, with axis vertical, to the structure. The device permits varying the damping of structural vibrations.

An air-bearing weight offload system for ground test of heavy LSS structures

NASA Technical Reports Server (NTRS)

Rice, R. B.

1989-01-01

The capability and use of the Gravity Offload Facility (GOF) are discussed. Briefly explained are the: truss and base casting; carriage assembly; carriage weldment; vertical lift axis control; lifting cylinder; payload gimbal; motion base layout; and control processor.

A comparison between the dynamics of horizontal and vertical axis offshore floating wind turbines.

PubMed

Borg, M; Collu, M

2015-02-28

The need to further exploit offshore wind resources in deeper waters has led to a re-emerging interest in vertical axis wind turbines (VAWTs) for floating foundation applications. However, there has been little effort to systematically compare VAWTs to the more conventional horizontal axis wind turbine (HAWT). This article initiates this comparison based on prime principles, focusing on the turbine aerodynamic forces and their impact on the floating wind turbine static and dynamic responses. VAWTs generate substantially different aerodynamic forces on the support structure, in particular, a potentially lower inclining moment and a substantially higher torque than HAWTs. Considering the static stability requirements, the advantages of a lower inclining moment, a lower wind turbine mass and a lower centre of gravity are illustrated, all of which are exploitable to have a less costly support structure. Floating VAWTs experience increased motion in the frequency range surrounding the turbine [number of blades]×[rotational speed] frequency. For very large VAWTs with slower rotational speeds, this frequency range may significantly overlap with the range of wave excitation forces. Quantitative considerations are undertaken comparing the reference NREL 5 MW HAWT with the NOVA 5 MW VAWT. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Numerical study on aerodynamic damping of floating vertical axis wind turbines

NASA Astrophysics Data System (ADS)

Cheng, Zhengshun; Aagaard Madsen, Helge; Gao, Zhen; Moan, Torgeir

2016-09-01

Harvesting offshore wind energy resources using floating vertical axis wind turbines (VAWTs) has attracted an increasing interest in recent years. Due to its potential impact on fatigue damage, the aerodynamic damping should be considered in the preliminary design of a floating VAWT based on the frequency domain method. However, currently the study on aerodynamic damping of floating VAWTs is very limited. Due to the essential difference in aerodynamic load characteristics, the aerodynamic damping of a floating VAWT could be different from that of a floating horizontal axis wind turbine (HAWT). In this study, the aerodynamic damping of floating VAWTs was studied in a fully coupled manner, and its influential factors and its effects on the motions, especially the pitch motion, were demonstrated. Three straight-bladed floating VAWTs with identical solidity and with a blade number varying from two to four were considered. The aerodynamic damping under steady and turbulent wind conditions were estimated using fully coupled aero-hydro-servo-elastic time domain simulations. It is found that the aerodynamic damping ratio of the considered floating VAWTs ranges from 1.8% to 5.3%. Moreover, the aerodynamic damping is almost independent of the rotor azimuth angle, and is to some extent sensitive to the blade number.

Apparatus and process for making a superconducting magnet for particle accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarabak, A.J.; Sunderman, W.H.; Mendola, E.G.

1992-03-10

This patent describes an apparatus for manufacturing a coil of superconducting material. It comprises a horizontally disposed winding mandrel; an adjustable support for receiving a spool of superconducting material, the spool having a vertical axis; means for translating the spool of superconducting material in a generally oval path around the winding mandrel so that the superconducting material is de-reeled from the spool, in order to wind a predetermined amount of superconducting material onto the mandrel, such that a coil of superconducting material is formed; means for guiding the superconducting material from the spool so as to deliver the superconducting materialmore » to the winding mandrel on a plane perpendicular to the vertical axis of the spool and parallel with a winding plane on the winding mandrel; means for imparting a tensioning force on the superconducting material as it is guided from the spool; means for rotating the winding mandrel about the horizontal axis thereof; means for clamping the superconducting material against the winding mandrel as the wire is wound thereon; means for securing the coil to the winding mandrel for lifting mandrel with the coil thereon; and means for curing the coil of superconducting material whereby a finished coil of superconducting material is formed.« less

The approximation of anomalous magnetic field by array of magnetized rods

NASA Astrophysics Data System (ADS)

Denis, Byzov; Lev, Muravyev; Natalia, Fedorova

2017-07-01

The method for calculation the vertical component of an anomalous magnetic field from its absolute value is presented. Conversion is based on the approximation of magnetic induction module anomalies by the set of singular sources and the subsequent calculation for the vertical component of the field with the chosen distribution. The rods that are uniformly magnetized along their axis were used as a set of singular sources. Applicability analysis of different methods of nonlinear optimization for solving the given task was carried out. The algorithm is implemented using the parallel computing technology on the NVidia GPU. The approximation and calculation of vertical component is demonstrated for regional magnetic field of North Eurasia territories.

Heating equipment installation system

DOEpatents

Meuschke, Robert E.; Pomaibo, Paul P.

1991-01-01

A method for installing a heater unit assembly (52, 54) in a reactor pressure vessel (2) for performance of an annealing treatment on the vessel (2), the vessel (2) having a vertical axis, being open at the top, being provided at the top with a flange (6) having a horizontal surface, and being provided internally, at a location below the flange (6), with orientation elements (8) which are asymmetrical with respect to the vertical axis, by the steps of: providing an orientation fixture (10) having an upwardly extending guide member (18) and orientation elements (14, 16) and installing the orientation fixture (10) in the vessel (2) so that the orientation elements (14,16) of the orientation fixture (10) mate with the orientation elements (8) of the pressure vessel (2) in order to establish a defined position of the orientation fixture (10) in the pressure vessel (2), and so that the guide member (18) projects above the pressure vessel (2) flange (6); placing a seal ring (30) in a defined position on the pressure vessel (2) flange (6) with the aid of the guide member (18); mounting at least one vertical, upwardly extending guide stud (40) upon the seal ring (30); withdrawing the orientation fixture (10) from the pressure vessel (2); and moving the heater unit assembly (52,54) vertically downwardly into the pressure vessel (2) while guiding the heater unit assembly (52,54) along a path with the aid of the guide stud (40).

Assessment of the perception of verticality and horizontality with self-paced saccades.

PubMed

Pettorossi, V E; Bambagioni, D; Bronstein, A M; Gresty, M A

1998-07-01

We investigated the ability of human subjects (Ss) to make self-paced saccades in the earth-vertical and horizontal directions (space-referenced task) and in the direction of the head-vertical and horizontal axis (self-referenced task) during whole body tilts of 0 degrees, 22.5 degrees, 45 degrees and 90 degrees in the frontal (roll) plane. Saccades were recorded in the dark with computerised video-oculography. During space-referenced tasks, the saccade vectors did not fully counter-rotate to compensate for larger angles of body tilt. This finding is in agreement with the 'A' effect reported for the visual vertical. The error was significantly larger for saccades intended to be space-horizontal than space-vertical. This vertico-horizontal dissociation implies greater difficulty in defining horizontality than verticality with the non-visual motor task employed. In contrast, normal Ss (and an alabyrinthine subject tested) were accurate in orienting saccades to their own (cranio-centric) vertical and horizontal axes regardless of tilt indicating that cranio-centric perception is robust and apparently not affected by gravitational influences.

Normal modes of synchronous rotation

NASA Astrophysics Data System (ADS)

Varadi, Ferenc; Musotto, Susanna; Moore, William; Schubert, Gerald

2005-07-01

The dynamics of synchronous rotation and physical librations are revisited in order to establish a conceptually simple and general theoretical framework applicable to a variety of problems. Our motivation comes from disagreements between the results of numerical simulations and those of previous theoretical studies, and also because different theoretical studies disagree on basic features of the dynamics. We approach the problem by decomposing the orientation matrix of the body into perfectly synchronous rotation and deviation from the equilibrium state. The normal modes of the linearized equations are computed in the case of a circular satellite orbit, yielding both the periods and the eigenspaces of three librations. Libration in longitude decouples from the other two, vertical modes. There is a fast vertical mode with a period very close to the average rotational period. It corresponds to tilting the body around a horizontal axis while retaining nearly principal-axis rotation. In the inertial frame, this mode appears as nutation and free precession. The other vertical mode, a slow one, is the free wobble. The effects of the nodal precession of the orbit are investigated from the point of view of Cassini states. We test our theory using numerical simulations of the full equations of the dynamics and discuss the disagreements among our study and previous ones. The numerical simulations also reveal that in the case of eccentric orbits large departures from principal-axis rotation are possible due to a resonance between free precession and wobble. We also revisit the history of the Moon's rotational state and show that it switched from one Cassini state to another when it was at 46.2 Earth radii. This number disagrees with the value 34.2 derived in a previous study.

CFD simulations of power coefficients for an innovative Darrieus style vertical axis wind turbine with auxiliary straight blades

NASA Astrophysics Data System (ADS)

Arpino, F.; Cortellessa, G.; Dell'Isola, M.; Scungio, M.; Focanti, V.; Profili, M.; Rotondi, M.

2017-11-01

The increasing price of fossil derivatives, global warming and energy market instabilities, have led to an increasing interest in renewable energy sources such as wind energy. Amongst the different typologies of wind generators, small scale Vertical Axis Wind Turbines (VAWT) present the greatest potential for off grid power generation at low wind speeds. In the present work, Computational Fluid Dynamic (CFD) simulations were performed in order to investigate the performance of an innovative configuration of straight-blades Darrieus-style vertical axis micro wind turbine, specifically developed for small scale energy conversion at low wind speeds. The micro turbine under investigation is composed of three pairs of airfoils, consisting of a main and auxiliary blades with different chord lengths. The simulations were made using the open source finite volume based CFD toolbox OpenFOAM, considering different turbulence models and adopting a moving mesh approach for the turbine rotor. The simulated data were reported in terms of dimensionless power coefficients for dynamic performance analysis. The results from the simulations were compared to the data obtained from experiments on a scaled model of the same VAWT configuration, conducted in a closed circuit open chamber wind tunnel facility available at the Laboratory of Industrial Measurements (LaMI) of the University of Cassino and Lazio Meridionale (UNICLAM). From the proposed analysis, it was observed that the most suitable model for the simulation of the performances of the micro turbine under investigation is the one-equation Spalart-Allmaras, even if under the conditions analysed in the present work and for TSR values higher than 1.1, some discrepancies between numerical and experimental data can be observed.

A Kinematic Model for Vertical Axis Rotation within the Mina Deflection of the Walker Lane

NASA Astrophysics Data System (ADS)

Gledhill, T.; Pluhar, C. J.; Johnson, S. A.; Lindeman, J. R.; Petronis, M. S.

2016-12-01

The Mina Deflection, at the boundary between the Central and Southern Walker Lane, spans the California-Nevada border and includes a heavily-faulted Pliocene volcanic field overlying Miocene ignimbrites. The dextral Walker Lane accommodates 25% of relative Pacific-North America plate motion and steps right across the sinistral Mina deflection. Ours and previous work shows that the Mina Deflection partially accommodates deformation by vertical-axis rotation of up to 99.9o ± 6.1o rotation since 11 Ma. This rotation is evident in latite ignimbrite of Gilbert et al. (1971), which we have formalized as three members of Tuff of Huntoon Creek (THC). The welded, basal, normal-polarity Huntoon Valley Member of THC is overlain by the unwelded to partially-welded, reversed-polarity Adobe Hills Mbr. This member includes internal breaks suggesting multiple eruptive phases, but the paleomagnetic results from each are statistically indistinguishable, meaning that they were likely erupted in rapid succession (within a few centuries of one another). THC ends with a welded member exhibiting very shallow inclination and south declination that we call Excursional Mbr. One of the upper members has been dated at 11.17 ± 0.04 Ma. These Miocene units are overlain by Pliocene basalts, Quaternary alluvium, and lacustrine deposits. Our paleomagnetic results show a gradient between the zero rotation domain and high rotation across a 20km baseline. A micropolar model, based on 25 years of earthquake data from the Northern and Southern California Seismic Network, suggest the Mina Deflection is currently experiencing transpressional seismogenic deformation (Unruh et al., 2003). Accepting Unruh's model and assuming continuous rotation since 11 Ma, we propose a kinematic model for the western Mina Deflection that accommodates 90o of vertical axis rotation from N-S to ENE-WSW oriented blocks.

High fill-factor micromirror array using a self-aligned vertical comb drive actuator with two rotational axes

NASA Astrophysics Data System (ADS)

Kim, Minsoo; Park, Jae-Hyoung; Jeon, Jin-A.; Yoo, Byung-Wook; Park, I. H.; Kim, Yong-Kweon

2009-03-01

We present a two-axis micromirror array with high fill-factor, using a new fabrication procedure on the full wafer scale. The micromirror comprises a self-aligned vertical comb drive actuator with a mirror plate mounted on it and electrical lines on a bottom substrate. A high-aspect-ratio vertical comb drive was built using a bulk micromachining technique on a silicon-on-insulator (SOI) wafer. The thickness of the torsion spring was adjusted using multiple silicon etching steps to enhance the static angular deflection of the mirrors. To address the array, electrical lines were fabricated on a glass substrate and combined with the comb actuators using an anodic bonding process. The silicon mirror plate was fabricated together with the actuator using a wafer bonding process and segmented at the final release step. The actuator and addressing lines were hidden behind the mirror plate, resulting in a high fill-factor of 84% in an 8 × 8 array of micromirrors, each 340 µm × 340 µm. The fabricated mirror plate has a high-quality optical surface with an average surface roughness (Ra) of 4 nm and a curvature radius of 0.9 m. The static and dynamic responses of the micromirror were characterized by comparing the measured results with the calculated values. The maximum static optical deflection for the outer axis is 4.32° at 60 V, and the maximum inner axis tilting angle is 2.82° at 96 V bias. The torsion resonance frequencies along the outer and inner axes were 1.94 kHz and 0.95 kHz, respectively.

Dike orientations in the late jurassic independence dike swarm and implications for vertical-axis tectonic rotations in eastern California

USGS Publications Warehouse

Hopson, R.F.; Hillhouse, J.W.; Howard, K.A.

2008-01-01

Analysis of the strikes of 3841 dikes in 47 domains in the 500-km-long Late Jurassic Independence dike swarm indicates a distribution that is skewed clockwise from the dominant northwest strike. Independence dike swarm azimuths tend to cluster near 325?? ?? 30??, consistent with initial subparallel intrusion along much of the swarm. Dike azimuths in a quarter of the domains vary widely from the dominant trend. In domains in the essentially unrotated Sierra Nevada block, mean dike azimuths range mostly between 300?? and 320??, with the exception of Mount Goddard (247??). Mean dike azimuths in domains in the Basin and Range Province in the Argus, Inyo, and White Mountains areas range from 291?? to 354?? the mean is 004?? in the El Paso Mountains. In the Mojave Desert, mean dike azimuths range from 318?? to 023??, and in the eastern Transverse Ranges, they range from 316?? to 051??. Restoration for late Cenozoic vertical-axis rotations, suggested by paleodeclinations determined from published studies from nearby Miocene and younger rocks, shifts dike azimuths into better agreement with azimuths measured in the tectonically stable Sierra Nevada. This confirms that vertical-axis tectonic rotations explain some of the dispersion in orientation, especially in the Mojave Desert and eastern Transverse Ranges, and that the dike orientations can be a useful if imperfect guide to tectonic rotations where paleomagnetic data do not exist. Large deviations from the main trend of the swarm may reflect (1) clockwise rotations for which there is no paleomagnetic evidence available, (2) dike intrusions of other ages, (3) crack filling at angles oblique or perpendicular to the main swarm, (4) pre-Miocene rotations, or (5) unrecognized domain boundaries between dike localities and sites with paleomagnetic determinations. ?? 2008 The Geological Society of America.

Vestibular adaptation to space in monkeys.

PubMed

Dai, M; Raphan, T; Kozlovskaya, I; Cohen, B

1998-07-01

Otolith-induced eye movements of rhesus monkeys were studied before and after the 1989 COSMOS 2044 and the 1992 to 1993 COSMOS 2229 flights. Two animals flew in each mission for approximately 2 weeks. After flight, spatial orientation of the angular vestibulo-ocular reflex was altered. In one animal the time constant of postrotatory nystagmus, which had been shortened by head tilts with regard to gravity before flight, was unaffected by the same head tilts after flight. In another animal, eye velocity, which tended to align with a gravitational axis before flight, moved toward a body axis after flight. This shift of orientation disappeared by 7 days after landing. After flight, the magnitude of compensatory ocular counter-rolling was reduced by about 70% in both dynamic and static tilts. Modulation in vergence in response to naso-occipital linear acceleration during off-vertical axis rotation was reduced by more than 50%. These changes persisted for 11 days after recovery. An up and down asymmetry of vertical nystagmus was diminished for 7 days. Gains of the semicircular canal-induced horizontal and vertical angular vestibulo-ocular reflexes were unaffected in both flights, but the gain of the roll angular vestibulo-ocular reflex was decreased. These data indicate that there are short- and long-term changes in otolith-induced eye movements after adaptation to microgravity. These experiments also demonstrate the unique value of the monkey as a model for studying effects of vestibular adaptation in space. Eye movements can be measured in three dimensions in response to controlled vestibular and visual stimulation, and the results are directly applicable to human beings. Studies in monkeys to determine how otolith afferent input and central processing is altered by adaptation to microgravity should be an essential component of future space-related research.

Vestibular adaptation to space in monkeys

NASA Technical Reports Server (NTRS)

Dai, M.; Raphan, T.; Kozlovskaya, I.; Cohen, B.

1998-01-01

Otolith-induced eye movements of rhesus monkeys were studied before and after the 1989 COSMOS 2044 and the 1992 to 1993 COSMOS 2229 flights. Two animals flew in each mission for approximately 2 weeks. After flight, spatial orientation of the angular vestibulo-ocular reflex was altered. In one animal the time constant of postrotatory nystagmus, which had been shortened by head tilts with regard to gravity before flight, was unaffected by the same head tilts after flight. In another animal, eye velocity, which tended to align with a gravitational axis before flight, moved toward a body axis after flight. This shift of orientation disappeared by 7 days after landing. After flight, the magnitude of compensatory ocular counter-rolling was reduced by about 70% in both dynamic and static tilts. Modulation in vergence in response to naso-occipital linear acceleration during off-vertical axis rotation was reduced by more than 50%. These changes persisted for 11 days after recovery. An up and down asymmetry of vertical nystagmus was diminished for 7 days. Gains of the semicircular canal-induced horizontal and vertical angular vestibulo-ocular reflexes were unaffected in both flights, but the gain of the roll angular vestibulo-ocular reflex was decreased. These data indicate that there are short- and long-term changes in otolith-induced eye movements after adaptation to microgravity. These experiments also demonstrate the unique value of the monkey as a model for studying effects of vestibular adaptation in space. Eye movements can be measured in three dimensions in response to controlled vestibular and visual stimulation, and the results are directly applicable to human beings. Studies in monkeys to determine how otolith afferent input and central processing is altered by adaptation to microgravity should be an essential component of future space-related research.

Rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada

NASA Astrophysics Data System (ADS)

Rood, Dylan H.; Burbank, Douglas W.; Herman, Scott W.; Bogue, Scott

2011-10-01

We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. Samples from the Upper Miocene (˜9 Ma) Eureka Valley Tuff suggest clockwise vertical-axis block rotations between NE-striking left-lateral faults in the Bridgeport and Mono Basins. Results in the Bodie Hills suggest clockwise rotations (R ± ΔR, 95% confidence limits) of 74 ± 8° since Early to Middle Miocene (˜12-20 Ma), 42 ± 11° since Late Miocene (˜8-9 Ma), and 14 ± 10° since Pliocene (˜3 Ma) time with no detectable northward translation. The data are compatible with a relatively steady rotation rate of 5 ± 2° Ma-1 (2σ) since the Middle Miocene over the three examined timescales. The average rotation rates have probably not varied by more than a factor of two over time spans equal to half of the total time interval. Our paleomagnetic data suggest that block rotations in the region of the Mina Deflection began prior to Late Miocene time (˜9 Ma), and perhaps since the Middle Miocene if rotation rates were relatively constant. Block rotation in the Bodie Hills is similar in age and long-term average rate to rotations in the Transverse Ranges of southern California associated with early transtensional dextral shear deformation. We speculate that the age of rotations in the Bodie Hills indicates dextral shear and strain accommodation within the central Walker Lane Belt resulting from coupling of the Pacific and North America plates.

Development of ride comfort criteria for mass transit systems

NASA Technical Reports Server (NTRS)

Kirby, R. H.; Mikulka, P. J.; Coates, G. D.

1976-01-01

Two studies were conducted on the effects of simultaneous sinusoidal vibration in the vertical and lateral axes on ratings of discomfort in human subjects in a simulated passenger aircraft. In the first experiment each of 24 subjects experienced each of ten levels of vertical frequency in combination with each of ten levels of lateral frequency vibration and rated the discomfort produced on a nine-point, unipolar scale. In the second experiment 72 subjects experienced one of four levels of vertical frequency at each of four levels of vertical amplitude combined with 16 (or 4 x 4) lateral frequency and amplitude conditions. The results of these two studies strongly suggest that there are effects on discomfort that occur when subjects are vibrated in several axes at once that cannot be assessed with research using vibration in only one axis.

Interpreting plant responses to clinostating. I - Mechanical stresses and ethylene

NASA Technical Reports Server (NTRS)

Salisbury, Frank B.; Wheeler, Raymond M.

1981-01-01

The possibility that the clinostat mechanical stresses (leaf flopping) induces ethylene production and, thus, the development of epinasty was tested by stressing vertical plants by constant gentle horizontal or vertical shaking or by a quick back-and-forth rotation (twisting). Clinostat leaf flopping was closely approximated by turning plants so that their stems were horizontal, rotating them quickly about the stem axis, and returning them to the vertical, with the treatment repeated every four minutes. It was found that horizontal and vertical shaking, twisting, intermittent horizontal rotating, and gentle hand shaking failed to induce epinasties that approached those observed on the slow clinostat. Minor epinasties were generated by vigorous hand-shaking (120 sec/day) and by daily application of Ag(+). Reducing leaf displacements by inverting plants did not significantly reduce the minor epinasty generated by vigorous hand-shaking.

AVOSS Windline at Dallas/Ft. Worth Airport Volume 1 Installation and Operation

DOT National Transportation Integrated Search

2001-05-01

A 259-meter windline, with horizontal and vertical single-axis anemometers mounted on 9-meter poles, was installed at the Dallas/Ft. Worth Airport under the approach to Runway 17C, as part of NASA's Aircraft Vortex Spacing System (AVOSS) development ...

Alcoa wind turbines

NASA Technical Reports Server (NTRS)

Ai, D. K.

1979-01-01

An overview of Alcoa's wind energy program is given with emphasis on the the development of a low cost, reliable Darrieus Vertical Axis Wind Turbine System. The design layouts and drawings for fabrication are now complete, while fabrication and installation to utilize the design are expected to begin shortly.

Comparison of aerodynamic models for Vertical Axis Wind Turbines

NASA Astrophysics Data System (ADS)

Simão Ferreira, C.; Aagaard Madsen, H.; Barone, M.; Roscher, B.; Deglaire, P.; Arduin, I.

2014-06-01

Multi-megawatt Vertical Axis Wind Turbines (VAWTs) are experiencing an increased interest for floating offshore applications. However, VAWT development is hindered by the lack of fast, accurate and validated simulation models. This work compares six different numerical models for VAWTS: a multiple streamtube model, a double-multiple streamtube model, the actuator cylinder model, a 2D potential flow panel model, a 3D unsteady lifting line model, and a 2D conformal mapping unsteady vortex model. The comparison covers rotor configurations with two NACA0015 blades, for several tip speed ratios, rotor solidity and fixed pitch angle, included heavily loaded rotors, in inviscid flow. The results show that the streamtube models are inaccurate, and that correct predictions of rotor power and rotor thrust are an effect of error cancellation which only occurs at specific configurations. The other four models, which explicitly model the wake as a system of vorticity, show mostly differences due to the instantaneous or time averaged formulation of the loading and flow, for which further research is needed.

Vertical-axis wind turbine development in Canada

NASA Astrophysics Data System (ADS)

Templin, R. J.; Rangi, R. S.

1983-12-01

Recent Canadian progress in the development of the curved-blade Darrieus vertical-axis wind turbine (VAWT) is described. Cooperation between government, industry and power utilities in the conduct of field trials, over several years, has demonstrated improved performance and reliability of grid-coupled turbines of this type. The rated power of the VAWTs currently under test ranges from 30 kW, in a wind/diesel powerplant, to 230 kW, in an installation on an island in the Gulf of St. Lawrence. Progress has also been made in understanding the basic aerodynamic behavior of the VAWT and theoretical methods for performance and load prediction have correspondingly improved. A brief description is given of 'Project EOLE', a cooperative project between the federal government and the utility Hydro-Quebec to develop and test, during the next two to three years, a 4 MW VAWT prototype, which will be coupled to the power grid at a location on the south shore of the St. Lawrence River.

Panel method for the wake effects on the aerodynamics of vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Goyal, Udit; Rempfer, Dietmar

2011-11-01

A formulation based on the panel method is implemented for studying the unsteady aerodynamics of straight-bladed vertical-axis wind turbines. A combination of source and vortex distributions is used to represent an airfoil in Darrieus type motion. Our approach represents a low-cost computational technique that takes into account the dynamic changes in angle of attack of the blade during a cycle. A time-stepping mechanism is introduced for the wake convection, and its effects on the aerodynamic forces on the blade are discussed. The focus of the study is to describe the effect of the trailing wakes on the upstream flow conditions and coefficient of performance of the turbines. Results show a decrease in Cp until the wake structure develops and assumes a quasi-steady behavior. A comparison with other models such as single and multiple streamtubes is discussed, and optimization of the blade pitch angle is performed to increase the instantaneous torque and hence the power output from the turbine.

Model tests of wind turbine with a vertical axis of rotation type Lenz 2

NASA Astrophysics Data System (ADS)

Zwierzchowski, Jaroslaw; Laski, Pawel Andrzej; Blasiak, Slawomir; Takosoglu, Jakub Emanuel; Pietrala, Dawid Sebastian; Bracha, Gabriel Filip; Nowakowski, Lukasz

A building design of vertical axis wind turbines (VAWT) was presented in the article. The construction and operating principle of a wind turbine were described therein. Two VAWT turbine models were compared, i.a. Darrieus and Lenz2, taking their strengths and weaknesses into consideration. 3D solid models of turbine components were presented with the use of SolidWorks software. Using CFD methods, the air flow on two aerodynamic fins, symmetrical and asymmetrical, at different angles of attack were tested. On the basis of flow simulation conducted in FlowSimulation, an asymmetrical fin was chosen as the one showing greater load bearing capacities. Due to the uncertainty of trouble-free operation of Darrieus turbine on construction elements creating the basis thereof, a 3D model of Lenz2 turbine was constructed, which is more reliable and makes turbine self-start possible. On the basis of the research, components were designed and technical docu mentation was compiled.

Study of Vertical Axis Wind Turbine for Energy Harvester in A Fishing Boat

NASA Astrophysics Data System (ADS)

Budi, E. M.; Banjarnahor, D. A.; Hanifan, M.

2017-07-01

The wind speed in the southern beach of West Java Indonesia is quite promising for wind energy harvesting. A field survey reported that the wind speed reached 10 m/s, while the average recorded in a year is about 4.7 m/s. In this study, two vertical axis wind turbines (VAWT) were compared to be used in that area through calculation as well as experiments. The experiments measured that the turbines can produce about 7.82W and 2.33W of electricity respectively. These experiments are compared with theoretical calculation to obtain the performance of both turbines used. The coefficient of performance (cp) experimentally is 0.09 for Turbine 1 (hybrid Savonius-Darrieus rotor) and 0.14 for Turbine 2 (Savonius rotor). While, rotor’s mechanical performance Cpr, obtained theoritically through calculation, is 0.36 for Turbine 1 and 0.12 for Turbine 2. These results are analysed from mechanical and electrical view.

Study of turbine and guide vanes integration to enhance the performance of cross flow vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Wibowo, Andreas; Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi; Situmorang, Marcelinus Risky Clinton

2018-02-01

The main purpose of this study is to investigate the best configuration between guide vanes and cross flow vertical axis wind turbine with variation of several parameters including guide vanes tilt angle and the number of turbine and guide vane blades. The experimental test were conducted under various wind speed and directions for testing cross flow wind turbine, consisted of 8, 12 and 16 blades. Two types of guide vane were developed in this study, employing 20° and 60° tilt angle. Both of the two types of guide vane had three variations of blade numbers which had same blade numbers variations as the turbines. The result showed that the configurations between 60° guide vane with 16 blade numbers and turbine with 16 blade numbers had the best configurations. The result also showed that for certain configuration, guide vane was able to increase the power generated by the turbine significantly by 271.39% compared to the baseline configuration without using of guide vane.

Low order physical models of vertical axis wind turbines

NASA Astrophysics Data System (ADS)

Craig, Anna; Dabiri, John; Koseff, Jeffrey

2016-11-01

In order to examine the ability of low-order physical models of vertical axis wind turbines to accurately reproduce key flow characteristics, experiments were conducted on rotating turbine models, rotating solid cylinders, and stationary porous flat plates (of both uniform and non-uniform porosities). From examination of the patterns of mean flow, the wake turbulence spectra, and several quantitative metrics, it was concluded that the rotating cylinders represent a reasonably accurate analog for the rotating turbines. In contrast, from examination of the patterns of mean flow, it was found that the porous flat plates represent only a limited analog for rotating turbines (for the parameters examined). These findings have implications for both laboratory experiments and numerical simulations, which have previously used analogous low order models in order to reduce experimental/computational costs. NSF GRF and SGF to A.C; ONR N000141211047 and the Gordon and Betty Moore Foundation Grant GBMF2645 to J.D.; and the Bob and Norma Street Environmental Fluid Mechanics Laboratory at Stanford University.

Large Eddy Simulation of Vertical Axis Wind Turbine wakes; Part I: from the airfoil performance to the very far wake

NASA Astrophysics Data System (ADS)

Chatelain, Philippe; Duponcheel, Matthieu; Caprace, Denis-Gabriel; Marichal, Yves; Winckelmans, Gregoire

2017-11-01

A vortex particle-mesh (VPM) method with immersed lifting lines has been developed and validated. Based on the vorticity-velocity formulation of the Navier-Stokes equations, it combines the advantages of a particle method and of a mesh-based approach. The immersed lifting lines handle the creation of vorticity from the blade elements and its early development. Large-eddy simulation (LES) of vertical axis wind turbine (VAWT) flows is performed. The complex wake development is captured in detail and over up to 15 diameters downstream: from the blades to the near-wake coherent vortices and then through the transitional ones to the fully developed turbulent far wake (beyond 10 rotor diameters). The statistics and topology of the mean flow are studied with respect to the VAWT geometry and its operating point. The computational sizes also allow insights into the detailed unsteady vortex dynamics and topological flow features, such as a recirculation region influenced by the tip speed ratio and the rotor geometry.

Flow measurement behind a pair of vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Parker, Colin M.; Hummels, Raymond; Leftwich, Megan C.

2017-11-01

The wake from a pair of vertical-axis wind turbines (VAWTs) is measured using particle imaging velocimetry (PIV). The VAWT models are mounted in a low-speed wind tunnel and driven using a motor control system. The rotation of the turbines is synced using a proportional controller that allows the turbine's rotational position to be set relative to each other. The rotation of the turbines is also synced with the PIV system for taking phase averaged results. The VAWTs are tested for both co- and counter-rotating cases over a range of relative phase offsets. Time averaged and phase averaged results are measured at the horizontal mid-plane in the near wake. The time-averaged results compare the bulk wake profiles from the pair of turbines. Phase averaged results look at the vortex interactions in the near wake of the turbines. By changing the phase relation between the turbines we can see the impact of the structure interactions in both the phase and time averaged results.