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1

Extensible Wind Towers  

NASA Astrophysics Data System (ADS)

The diffusion of wind energy generators is restricted by their strong landscape impact. The PERIMA project is about the development of an extensible wind tower able to support a wind machine for several hundred kW at its optimal working height, up to more than 50 m. The wind tower has a telescopic structure, made by several tubes located inside each other with their axis in vertical direction. The lifting force is given by a jack-up system confined inside a shaft, drilled below the ground level. In the retracted tower configuration, at rest, tower tubes are hidden in the foundation of the telescopic structure, located below the ground surface, and the wind machine is the only emerging part of the system. The lifting system is based on a couple of oleodynamic cylinders that jack-up a central tube connected to the top of the tower by a spring, with a diameter smaller than the minimum tower diameter and with a length a bit greater than the length of the extended telescopic structure. The central tube works as plunger and lifts all telescopic elements. The constraint between the telescopic elements is ensured by special parts, which are kept in traction by the force of the spring and provide the resisting moment. The most evident benefit of the proposed system is attained with the use of a two-blade propeller, which can be kept horizontal in the retracted tower configuration.

Sinagra, Marco; Tucciarelli, Tullio

2

Wind tower augmentation of wind turbines  

Microsoft Academic Search

The operating principle of the 'Baud-Geers' wind towers traditionally used in Iran for ventilation and passive cooling of architectural structures is presently adapted to house a vertical axis wind turbine. Unlike annular diffuser-augmented, horizontal axis wind turbines, the 'wind tower' does not have to be trained into the wind and generates less noise. It may also be either free standing

M. N. Bahadori

1984-01-01

3

Wind tower turbine  

Microsoft Academic Search

A wind powered turbine drive for an electric generator is disclosed in which both the generator and the turbine driving it are stationary and remain in a fixed position irrespective of wind direction. This turbine facilitates electric power generation by wind power in those higher power ranges where the greater generator and turbine weights otherwise make it difficult and costly

OHare

1981-01-01

4

Wind turbine tower for storing hydrogen and energy  

DOEpatents

A wind turbine tower assembly for storing compressed gas such as hydrogen. The tower assembly includes a wind turbine having a rotor, a generator driven by the rotor, and a nacelle housing the generator. The tower assembly includes a foundation and a tubular tower with one end mounted to the foundation and another end attached to the nacelle. The tower includes an in-tower storage configured for storing a pressurized gas and defined at least in part by inner surfaces of the tower wall. In one embodiment, the tower wall is steel and has a circular cross section. The in-tower storage may be defined by first and second end caps welded to the inner surface of the tower wall or by an end cap near the top of the tower and by a sealing element attached to the tower wall adjacent the foundation, with the sealing element abutting the foundation.

Fingersh, Lee Jay (Westminster, CO)

2008-12-30

5

Summary of tower designs for large horizontal axis wind turbines  

NASA Technical Reports Server (NTRS)

Towers for large horizontal axis wind turbines, machines with a rotor axis height above 30 meters and rated at more than 500 kW, have varied in configuration, materials of construction, type of construction, height, and stiffness. For example, the U.S. large HAWTs have utilized steel truss type towers and free-standing steel cylindrical towers. In Europe, the trend has been to use only free-standing and guyed cylindrical towers, but both steel and reinforced concrete have been used as materials of construction. These variations in materials of construction and type of construction reflect different engineering approaches to the design of cost effective towers for large HAWTs. Tower designs are the NASA/DOE Mod-5B presently being fabricated. Design goals and requirements that influence tower configuration, height and materials are discussed. In particular, experiences with United States large wind turbine towers are elucidated. Finally, current trends in tower designs for large HAWTs are highlighted.

Frederick, G. R.; Savino, J. M.

1986-01-01

6

Marion Meteorological Tower Wind Monitoring This document provides information not repeated in the monthly wind monitoring  

E-print Network

Marion Meteorological Tower Wind Monitoring This document provides information not repeated on the meteorological tower at Marion: Great Hill Dairy. A wind vane and two anemometers are located at two heights

Massachusetts at Amherst, University of

7

Remote monitoring and nondestructive evaluation of wind turbine towers  

NASA Astrophysics Data System (ADS)

Wind turbine towers are in need of condition monitoring so as to lower the cost of unexpected maintenance. Wind loading from turbulence and gusts can cause damage in horizontal axis wind turbines even the supporting towers. Monitoring of wind turbines in service using embedded data sensor arrays usually is not targeted at the turbine-tower interaction from the perspective of structural dynamics. In this study the remote monitoring of the tower supporting a horizontal-axis wind turbine was attempted using a microwave interferometer. The dominant frequency of one tower was found to be decreased by more than 20% in 16 months. Numerical modeling using spectral finite elements is in progress and should provide further information regarding frequency shift due to stiffness variation and added mass. Expected outcome will contribute to remote monitoring procedures and nondestructive evaluation techniques for local wind turbine structures during operation.

Chiang, Chih-Hung; Yu, Chih-Peng; Hsu, Keng-Tsang; Cheng, Chia-Chi; Ke, Ying-Tzu; Shih, Yi-Ru

2014-03-01

8

77 FR 46058 - Utility Scale Wind Towers From the Socialist Republic of Vietnam: Preliminary Determination of...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [A-552-814] Utility Scale Wind Towers From the Socialist Republic of Vietnam: Preliminary...Department'') preliminarily determines that utility scale wind towers (``wind towers'') from the Socialist Republic of...

2012-08-02

9

78 FR 11146 - Utility Scale Wind Towers From the People's Republic of China: Antidumping Duty Order  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [A-570-981] Utility Scale Wind Towers From the People's Republic of China: Antidumping...is issuing an antidumping duty order on utility scale wind towers (``wind towers'') from the People's Republic of...

2013-02-15

10

78 FR 11152 - Utility Scale Wind Towers from the People's Republic of China: Countervailing Duty Order  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [C-570-982] Utility Scale Wind Towers from the People's Republic of China: Countervailing...issuing a countervailing duty order on utility scale wind towers (``wind towers'') from the People's Republic of...

2013-02-15

11

77 FR 75978 - Utility Scale Wind Towers From the People's Republic of China: Final Affirmative Countervailing...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [C-570-982] Utility Scale Wind Towers From the People's Republic of China: Final...provided to producers and exporters of utility scale wind towers (wind towers) from the People's Republic of China...

2012-12-26

12

Wind Shear Characteristics at Central Plains Tall Towers (presentation)  

SciTech Connect

The objectives of this report are: (1) Analyze wind shear characteristics at tall tower sites for diverse areas in the central plains (Texas to North Dakota)--Turbines hub heights are now 70-100 m above ground and Wind measurements at 70-100+ m have been rare. (2) Present conclusions about wind shear characteristics for prime wind energy development regions.

Schwartz, M.; Elliott, D.

2006-06-05

13

77 FR 33422 - Utility Scale Wind Towers From the People's Republic of China: Preliminary Affirmative...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Administration [C-570-982] Utility Scale Wind Towers From the People's Republic of...producers and exporters of utility scale wind towers from the People's Republic of...petition concerning imports of utility scale wind towers (wind towers) from the...

2012-06-06

14

A Meso-Climatology Study of the High-Resolution Tower Network Over the Florida Spaceport  

NASA Technical Reports Server (NTRS)

Forecasters at the US Air Force 45th Weather Squadron (45 WS) use wind and temperature data from the tower network over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) to evaluate Launch Commit Criteria and to issue and verify temperature and wind advisories, watches, and warnings for ground operations. The Spaceflight Meteorology Group at the Johnson Space Center in Houston, TX also uses these data when issuing forecasts for shuttle landings at the KSC Shuttle Landing Facility. Systematic biases in these parameters at any of the towers could adversely affect an analysis, forecast, or verification for all of these operations. In addition, substantial geographical variations in temperature and wind speed can occur under specific wind directions. Therefore, the Applied Meteorology Unit (AMU), operated by ENSCO Inc., was tasked to develop a monthly and hourly climatology of temperatures and winds from the tower network, and identify the geographical variation, tower biases, and the magnitude of those biases. This paper presents a sub-set of results from a nine-year climatology of the KSC/CCAFS tower network, highlighting the geographical variations based on location, month, times of day, and specific wind direction regime. Section 2 provides a description of the tower mesonetwork and instrumentation characteristics. Section 3 presents the methodology used to construct the tower climatology including QC methods and data processing. The results of the tower climatology are presented in Section 4 and Section 5 summarizes the paper.

Case, Jonathan L.; Bauman, William H., III

2004-01-01

15

Comparison of Second Wind Triton Data with Meteorological Tower Measurements  

SciTech Connect

With the increased interest in remote sensing of wind information in recent years, it is important to determine the reliability and accuracy of new wind measurement technologies if they are to replace or supplement conventional tower-based measurements. In this study, we present the results of an analysis characterizing the measurement performance of a state-of-the-art SOund Detection And Ranging (sodar) device when compared to a high-quality tower measurement program. Second Wind Inc. (Somerville, MA, USA) provided NREL with more than six months of data from a measurement program conducted near an operating wind farm in western Texas.

Scott, G.; Elliott, D.; Schwartz, M.

2010-02-01

16

Automatically controlled wind propeller and tower shadow eliminator  

SciTech Connect

A propeller hub carries pivotally-mounted blades that are linked to a spring-loaded collar on the propeller shaft for automatic coning and feathering under predetermined high velocity movement along the propeller shaft to change the blade pitch angle during low wind velocity conditions. An airfoil support mounts a propeller shaft and turns therewith to reduce tower shadow effects. This is called a ''down-wind system'' meaning the propeller is behind the tower and causes the assembly to rotate into the wind without a tail vane.

Randolph, A.J.

1982-01-12

17

Galloping of internally resonant towers subjected to turbulent wind  

NASA Astrophysics Data System (ADS)

Bifurcation analysis of a structure constituted by two towers, linked by a viscous device at the tip and subjected to turbulent wind, is carried out. The towers have geometrical and mechanical parameters so that the steady part of the wind, whose contribution is evaluated in the framework of the steady theory, induces a 1:1 resonant double-Hopf bifurcation. The turbulent part of the wind, assumed as composed by two frequencies that are equal and double to the main frequency of the unlinked towers, respectively, induces parametric and external harmonic forces. These forces interact with the self-excitation due to the steady part of the wind, bringing imperfection in the bifurcation scenario. Transitions from resonant to non-resonant cases are analyzed in terms of behavior charts, and post-critical dynamics is studied in the space of bifurcation parameters.

Zulli, Daniele; Di Egidio, Angelo

2014-09-01

18

Effect of dynamic wind loads on compliant towers  

SciTech Connect

Traditionally, the calculation of wind loads for offshore structures has been carried out using equivalent static loads applied on the deck. For compliant towers with a long natural period of vibration, the importance of the low frequency wind turbulence can become significant. This paper presents results of an investigation into the effects of dynamic wind loads on compliant tower responses. The investigation results indicate that the impact of using dynamic wind loads (based on a one-hour average wind speed with gust fluctuation) would be a reduction in dynamic tower responses when compared to those due to the static wind (based on a one-minute average wind speed) superimposed on the waves. Dynamic response reductions in the order of 5 to 8 percent may be realized from the dynamic wind loads. Hence, the use of equivalent static wind loads may overestimate the wind load contribution, although the overestimate may not be significant. Wind tunnel model tests may be necessary to further confirm this finding.

Chen, C.Y.; Will, S. [Hudson Engineering Corp., Houston, TX (United States)

1994-12-31

19

Numerical simulation of wind turbine blade-tower interaction  

NASA Astrophysics Data System (ADS)

Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface (AMI) method were presented. The governing equations were the unsteady Reynolds-averaged Navier-Stokes (RANS) which were solved by the pimpleDyMFoam solver, and the AMI method was employed to handle mesh movements. The National Renewable Energy Laboratory (NREL) phase VI wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds (5, 10, 15, and 25 m/s) at a fixed blade pitch and constant rotational speed. Detailed numerical results of vortex structure, time histories of thrust, and pressure distribution on the blade and tower were presented. The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine, while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower. Also, strong interaction of blade tip vortices with separation from the tower was observed.

Wang, Qiang; Zhou, Hu; Wan, Decheng

2012-09-01

20

77 FR 75984 - Utility Scale Wind Towers From the Socialist Republic of Vietnam: Final Determination of Sales at...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [A-552-814] Utility Scale Wind Towers From the Socialist Republic of Vietnam: Final...determination in the antidumping investigation of utility scale wind towers (``wind towers'') from the Socialist Republic of...

2012-12-26

21

77 FR 46034 - Utility Scale Wind Towers From the People's Republic of China: Preliminary Determination of Sales...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [A-570-981] Utility Scale Wind Towers From the People's Republic of China: Preliminary...Department'') preliminarily determines that utility scale wind towers (``wind towers'') from the People's Republic of...

2012-08-02

22

77 FR 75992 - Utility Scale Wind Towers From the People's Republic of China: Final Determination of Sales at...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [A-570-981] Utility Scale Wind Towers From the People's Republic of China: Final...determination in the antidumping investigation of utility scale wind towers (``wind towers'') from the People's Republic of...

2012-12-26

23

78 FR 11150 - Utility Scale Wind Towers From the Socialist Republic of Vietnam: Amended Final Determination of...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [A-552-814] Utility Scale Wind Towers From the Socialist Republic of Vietnam: Amended...is issuing an antidumping duty order on utility scale wind towers (``wind towers'') from the Socialist Republic of...

2013-02-15

24

On the analysis of the causes of cracking in a wind tower  

Microsoft Academic Search

This paper presents an analysis of the cracking causes in a wind tower of a wind farm. The cracks were detected in several towers of the farm, in the welded joint between the lower ring of the towers and the flange connecting the towers to their corresponding foundation. In the extreme case, here analysed, the crack was a through thickness

R. Lacalle; S. Cicero; J. A. Álvarez; R. Cicero; V. Madrazo

2011-01-01

25

Prediction of coastal winds using scatterometer and tower observations  

NASA Astrophysics Data System (ADS)

Possibility of predicting surface boundary layer winds over coastal land and ocean has been explored in this paper. Prediction has been effected using a modern nonlinear data-fitting algorithm known as genetic algorithm (GA) based on the Darwinian evolutionary theory. Time series of tower-mounted anemometer measured wind speed has been used for carrying out forecast over land while time series of satellite scatterometer derived winds has been used for forecast over coastal ocean. The prediction over land can feed into weather advisories required for rocket launching stations while prediction over coastal ocean can be of use in offshore industries.

Sarkar, Abhijit; Satheesan, K.; Basu, Sujit; Rama, G. V.

2006-12-01

26

Some techniques for reducing the tower shadow of the DOE/NASA mod-0 wind turbine tower. [wind tunnel tests to measure effects of tower structure on wind velocity  

NASA Technical Reports Server (NTRS)

Wind speed profile measurements to measure the effect of a wind turbine tower on the wind velocity are presented. Measurements were made in the wake of scale models of the tower and in the wake of certain full scale components to determine the magnitude of the speed reduction (tower shadow). Shadow abatement techniques tested on the towers included the removal of diagonals, replacement of diagonals and horizontals with round cross section members, installation of elliptical shapes on horizontal members, installation of airfoils on vertical members, and application of surface roughness to vertical members.

Burley, R. R.; Savino, J. M.; Wagner, L. H.; Diedrich, J. H.

1979-01-01

27

Experimental study on wind loading on a complicated group-tower  

NASA Astrophysics Data System (ADS)

This paper studied how wind pressures and forces affect rigid sectional models of a complicated group-tower using experimental wind tunnel tests. The group-tower was composed of five separate sub-towers with different diameters and heights. The basic characteristics of the mean and fluctuating wind pressure distributions on typical parts of the sub-towers were analyzed along the heights of each sub-tower, and their distribution trends are discussed. Also, the mean base shear and moment coefficients and their characteristics are presented. The wind pressure and wind force results showed that because the group-tower structure consisted of five separate lofty towers, the mutual aerodynamic interferences were serious; thus, the mean and fluctuating wind pressure, wind force distributions and the mean base shear and moment coefficients were quite complicated.

Ming, Gu; Huang, Peng; Tao, Lin; Zhou, Xuanyi; Fan, Zhong

2010-10-01

28

Numerical model for the flow within the tower of a tornado-type wind energy system  

SciTech Connect

A two-equation turbulence model is used to predict numerically the flow within the tower of a tornado-type wind energy system. Calculations are carried out for a tower in a uniform flow. Both cases of closed-bottom tower and simulated turbine flow with a variety of turbine-to-tower diameter ratios and turbine flow rates are considered. Calculated values of pressure for closed-bottom tower are compared with experimental values. 11 refs.

Ayad, S.S.

1981-11-01

29

Computer Simulation of Cooling Effect of Wind Tower on Passively Ventilated Building  

E-print Network

, without mechanical equipment. A simple computer program was developed to simulate airflow through a wind tower based on tower dimensions and air temperature. The program was compared to experimental results with reasonable agreement. Parametric... analysis indicates that interior air temperature approaches outdoor air temperature asymptotically as tower height and cross-sectional area are increased, and that it may be more cost effective to increase the tower?s height than its cross sectional...

Seryak, J.; Kissock, J. K.

2002-01-01

30

Performance prediction of a multi-stage wind tower for indoor cooling  

NASA Astrophysics Data System (ADS)

A theoretical model is developed to establish an in-depth understanding of the performance of a three-stage wind tower with a bypass system for indoor cooling in rural dry and hot climates. Model simulations are presented for a wide range of ambient conditions that include inlet wind speed, inlet temperature and relative humidity. Simulation results provide an insight into the desirable water flow rates and air-to-water loadings for comfort zone temperatures and relative humidity levels at the exit of the wind tower. Simulations show wind towers with variable cross-sections provide an increase in the cooling power for the same inlet wind speed, inlet air temperature and relative humidity when compared to wind towers with a constant cross-section. The study shall lead to a better understanding to designing wind towers that are both environmentally friendly and energy efficient.

Issa, Roy J.; Chang, Byungik

2012-08-01

31

Modification of pedestrian wind comfort in the Silvertop Tower passages by an automatic control system  

Microsoft Academic Search

The Silvertop Towers project is a comprehensive redevelopment project of three high-rise residential buildings in the city of Antwerp (Flanders, Belgium). As part of this project, pedestrian passages will be constructed through each of the towers to improve the accessibility and to increase social control on the site. Experience, wind tunnel modeling and numerical modeling have indicated that wind conditions

Bert Blocken; Staf Roels; Jan Carmeliet

2004-01-01

32

Vibration Based Wind Turbine Tower Foundation Design Utilizing Soil-Foundation-Structure Interaction  

Microsoft Academic Search

Wind turbines have been used to generate electricity as an alternative energy source to conventional fossil fuels. This case study is for multiple wind towers located at different villages in Alaska where severe arctic weather conditions exist. The towers are supported by two different types of foundations; large mat or deep piles foundations. Initially, a Reinforced Concrete (RC) mat foundation

P. E. Mohamed Al Satari; S. E. Saif Hussain

2008-01-01

33

77 FR 37653 - Utility Scale Wind Towers From the People's Republic of China: Alignment of Final Countervailing...  

Federal Register 2010, 2011, 2012, 2013, 2014

...determination in the countervailing duty (CVD) investigation of utility scale wind towers...Kristen Johnson or Patricia Tran, AD/ CVD Operations, Office 3, Import Administration...2012, the Department initiated the AD and CVD investigations of wind towers from the...

2012-06-22

34

Improvement of risk estimate on wind turbine tower buckled by hurricane  

E-print Network

Wind is one of the important reasonable resources. However, wind turbine towers are sure to be threatened by hurricanes. In this paper, method to estimate the number of wind turbine towers that would be buckled by hurricanes is discussed. Monte Carlo simulations show that our method is much better than the previous one. Since in our method, the probability density function of the buckling probability of a single turbine tower in a single hurricane is obtained accurately but not from one approximated expression. The result in this paper may be useful to the design and maintenance of wind farms.

Li, Jingwei

2013-01-01

35

77 FR 50715 - Utility Scale Wind Towers From China and Vietnam; Scheduling of the Final Phase of Countervailing...  

Federal Register 2010, 2011, 2012, 2013, 2014

...731-TA-1195-1196 (Final)] Utility Scale Wind Towers From China and Vietnam; Scheduling...from China and Vietnam of utility scale wind towers, provided for in subheading 7308...defined the subject merchandise as certain wind towers, whether or not tapered, and...

2012-08-22

36

Dynamic response of a compliant tower in wind and waves  

SciTech Connect

The study of damping was made using a surface piercing cylinder supported from a heavy three point pendulum system moving just above the water surface. The force and displacement time histories were recorded for a variety of free vibration damping tests, in still water, monochromatic and long crested random waves. The drag coefficient based on the relative velocity model was evaluated both from the damping traces and by matching of the measured and computed force time histories. Also in the course of the same experiment, the values of C{sub M},C{sub A} were measured using the matching method for the range of Re,Kc numbers observed in the damping test. The results obtained from the above study were then employed to predict the response of the scaled model (1:150) of a simple cantilever compliant tower to different wind/wave states in both frequency domain (linearized load) and stochastic time domain where the nonlinear drag force is considered in combination with the free surface effects. Finally the theoretical response is compared with the experimental results obtained in the wind/wave tank facility where the model was subjected to the combined action of the scaled random wave and wind loadings. 23 refs., 13 figs., 3 tabs.

Daneshvaran, M.T.S.; Vickery, B.J. [Univ. of Western Ontario, London, Ontario (Canada). Boundary Layer Wind Tunnel Lab.

1995-12-31

37

Tower and rotor blade vibration test results for a 100-kilowatt wind turbine  

NASA Technical Reports Server (NTRS)

The predominant natural frequencies and mode shapes for the tower and the rotor blades of the ERDA-NASA 100-kW wind turbine were determined. The tests on the tower and the blades were conducted both before and after the rotor blades and the rotating machinery were installed on top of the tower. The tower and each blade were instrumented with an accelerometer and impacted by an instrumented mass. The tower and blade structure was analyzed by means of NASTRAN, and computed values agree with the test data.

Linscott, B. S.; Shapton, W. R.; Brown, D.

1976-01-01

38

Approximate method for calculating free vibrations of a large-wind-turbine tower structure  

NASA Technical Reports Server (NTRS)

A set of ordinary differential equations were derived for a simplified structural dynamic lumped-mass model of a typical large-wind-turbine tower structure. Dunkerley's equation was used to arrive at a solution for the fundamental natural frequencies of the tower in bending and torsion. The ERDA-NASA 100-kW wind turbine tower structure was modeled, and the fundamental frequencies were determined by the simplified method described. The approximate fundamental natural frequencies for the tower agree within 18 percent with test data and predictions analyzed.

Das, S. C.; Linscott, B. S.

1977-01-01

39

Wind turbine generator application places unique demands on tower design and materials  

NASA Technical Reports Server (NTRS)

The most relevant contractual tower design requirements and goal for the Mod-1 tower are related to steel truss tower construction, cost-effective state-of-the-art design, a design life of 30 years, and maximum wind conditions of 120 mph at 30 feet elevation. The Mod-1 tower design approach was an iterative process. Static design loads were calculated and member sizes and overall geometry chosen with the use of finite element computer techniques. Initial tower dynamic characteristics were then combined with the dynamic properties of the other wind turbine components, and a series of complex dynamic computer programs were run to establish a dynamic load set and then a second tower design.

Kita, J. P.

1978-01-01

40

Vibration analysis of three guyed tower designs for intermediate size wind turbines  

NASA Technical Reports Server (NTRS)

Three guyed tower designs were analyzed for intermediate size wind turbines. The four lowest natural frequencies of vibration of the three towers concepts were estimated. A parametric study was performed on each tower to determine the effect of varying such tower properties as the inertia and stiffness of the tower and guys, the inertia values of the nacelle and rotor, and the rotational speed of the rotor. Only the two lowest frequencies were in a range where they could be excited by the rotor blade passing frequencies. There two frequencies could be tuned by varying the guy stiffness, the guy attachment point on the tower, the tower and mass stiffness, and the nacelle/rotor/power train masses.

Christie, R. J.

1982-01-01

41

Modified shape of the Eiffel Tower determined for an atmospheric boundary-layer wind profile  

NASA Astrophysics Data System (ADS)

The design and construction of the Eiffel Tower was based, in part, on a uniform horizontal wind model giving 300 kg m-2 kinematic pressure acting on the surface of the tower. Eiffel received a patent for his method of construction that eliminates the need for diagonal trellis bars used to resist the moment of an oncoming wind. At the end of the 19th century boundary-layer theory, laminar or turbulent, was nonexistent. Now, however, models for atmospheric flow over rough landscapes are available, the simplest being a power-law distribution of velocity with height. In this paper we deduce the shape of the tower had Eiffel incorporated this information into the design and construction of his world famous tower. Moreover, we prove Eiffel's observation that the tower profile conforms to the moment distribution wrought by the wind.

Weidman, P. D.

2009-06-01

42

Optimized frequency-based foundation design for wind turbine towers utilizing soil–structure interaction  

Microsoft Academic Search

This study illustrates design optimization for multiple wind towers located at different villages in Alaska. The towers are supported by two different types of foundations: large mat or deep piles foundations. Initially, a reinforced concrete (RC) mat foundation was proposed. Where soil conditions required it, a pile foundation solution was devised utilizing a 30in thick RC mat containing an embedded

Mohammad AlHamaydeh; Saif Hussain

2010-01-01

43

Wake characteristics of a tower for the DOE-NASA MOD-1 wind turbine  

NASA Technical Reports Server (NTRS)

A 1/40th scale model of a tower concept designed for a MOD-1 wind power turbine was tested in a low speed wind tunnel. Wake wind speed profiles were measured, and from these were determined local values of wake minimum velocity ratio, average velocity ratio, and width over a range of tower elevations and wind approach angles. Comparison with results from two other all tubular models (MOD-0 and eight leg designs) tested earlier in the same tunnel indicated that wake width and flow blockage at the rotor plane of rotation were slightly larger for the MOD-1 tower than for the other two models. The differences in wake characteristics were attributed to differences in tower geometry and member dimensions.

Savino, J. M.; Wagner, L. H.; Nash, M.

1978-01-01

44

EERE News: World Trade Center's Freedom Tower to Feature Wind Turbines  

NSDL National Science Digital Library

The DOE Office of Energy Efficiency and Renewable Energy posts a weekly electronic newsletter. This January 7, 2004 issue of features a story about the wind turbines which will be part of the forthcoming Freedom Tower to be located at the site of the World Trade Center. The story includes links to the press release from the architects, images of the Freedom Tower design, as well as images of the proposed wind turbine installation.

45

Static and dynamic investigations of different towers for wind turbines  

Microsoft Academic Search

The kinematics of a cantilevered, a conventional guyed, and a compliant (elastic column held by a rigid framework) tower were studied. The static layout of the towers is established, using the reactions due to different gusts which a two-bladed rotor (120 m diameter) imposes on a rigid support as external loads. The rotor blades are assumed to be inelastic. Each

J. H. Argyris; K. A. Braun

1980-01-01

46

Investigation of Natural Draft Cooling Tower Performance Using Neural Network  

NASA Astrophysics Data System (ADS)

In the present work Artificial Neural Network (ANN) technique is used to investigate the performance of Natural Draft Wet Cooling Tower (NDWCT). Many factors are affected the rang, approach, pressure drop, and effectiveness of the cooling tower which are; fill type, water flow rate, air flow rate, inlet water temperature, wet bulb temperature of air, and nozzle hole diameter. Experimental data included the effects of these factors are used to train the network using Back Propagation (BP) algorithm. The network included seven input variables (Twi, hfill, mw, Taiwb, Taidb, vlow, vup) and five output variables (ma, Taowb, Two, ?p, ?) while hidden layer is different for each case. Network results compared with experimental results and good agreement was observed between the experimental and theoretical results.

Mahdi, Qasim S.; Saleh, Saad M.; Khalaf, Basima S.

47

A new framework for evaluating along-wind responses of a transmission tower  

NASA Astrophysics Data System (ADS)

In this paper, an analytical framework to evaluate the along-wind-induced dynamic responses of a transmission tower is presented. Two analytical models and a new method are developed: (1) a higher mode generalized force spectrum (GFS) model of the transmission tower is deduced; (2) an analytical model that includes the contributions of the higher modes is further derived as a rational algebraic formula to estimate the structural displacement response; and (3) a new approach, applying load with displacement (ALD) instead of force, to solve the internal force of transmission tower is given. Unlike conventional methods, the ALD method can avoid calculating equivalent static wind loads (ESWLs). Finally, a transmission tower structure is used as a numerical example to verify the feasibility and accuracy of the ALD method.

Liu, Guohuan; Li, Hongnan

2009-03-01

48

Preliminary study on the applicability of semi-geodesic winding in the design and manufacturing of composite towers  

NASA Astrophysics Data System (ADS)

During last twenty years, wind turbine manufacturers took the path of building larger machines to generate more electricity. However, the bigger the size became, the more material was required to support the loads, leading to great weight increases. Larger turbines and higher hub heights also resulted in larger tower base diameters which are limited considering their logistics. In many countries, the limit for transports with special permits maximizes the diameter to 4.5 metres. Considering this fact, the wind turbine market dominated by welded steel shell towers is looking for new structural solutions for their future turbines. Although, composite materials are not used as the structural material in the towers of today's turbines, the demand for larger wind turbines forces engineers to seek for alternative material systems with high specific strength and stiffness ratios to be used in towers. Inspired by the applicability of filament winding in tower production, in the present article we investigated the effect of semi-geodesic winding on the winding angle, thickness, stiffness coefficients and vibration characteristics of filament wound composite conical shells of revolution which simulate wind turbine towers at the structural level. Present study showed that the preset friction applied during semi-geodesic winding is an important design parameter which can be controlled to obtain gradually increasing thickness from tower top to the base of the tower, and favourably alter the dynamic characteristics of the composite towers.

Kayran, A.; ?brahimo?lu, C. S.

2014-12-01

49

SHM BASED SYSTEM DESIGN OFA WIND TURBINE TOWER USING A MODAL SENSITIVITY BASED BAYES DETECTOR  

E-print Network

of the NREL 5MW wind turbine tower subjected to bending fatigue and horizontal circumferential cracking at weld locations. Decision driven SHM is shown to change the initial design safety of the structure in the fatigue limit state. A common optimum of material safety and classifier threshold is found, enabling

Boyer, Edmond

50

NREL National Wind Technology Center (NWTC): M2 Tower; Boulder, Colorado (Data)  

DOE Data Explorer

The National Wind Technology Center (NWTC), located at the foot of the Rocky Mountains near Boulder, Colorado, is a world-class research facility managed by NREL for the U.S. Department of Energy. NWTC researchers work with members of the wind energy industry to advance wind power technologies that lower the cost of wind energy through research and development of state-of-the-art wind turbine designs. NREL's Measurement and Instrument Data Center provides data from NWTC's M2 tower which are derived from instruments mounted on or near an 82 meter (270 foot) meteorological tower located at the western edge of the NWTC site and about 11 km (7 miles) west of Broomfield, and approximately 8 km (5 miles) south of Boulder, Colorado. The data represent the mean value of readings taken every two seconds and averaged over one minute. The wind speed and direction are measured at six heights on the tower and air temperature is measured at three heights. The dew point temperature, relative humidity, barometric pressure, totalized liquid precipitation, and global solar radiation are also available.

Jager, D.; Andreas, A.

51

Investigation on the impact of the environment wind velocity on the indirect air-cooling tower performance  

NASA Astrophysics Data System (ADS)

The wind velocity plays a crucial role in the operation characteristic of indirect cooling tower. In this paper a 2×330MW vertical arrangement indirect air-cooled system was taken as research object, and numerical simulation method was used to analyze the relative influence of the wind speed, ranging from 4m/s to 18m/s, on the outlet water temperature of cooling tower, the outlet air temperature of radiator, the facing wind speed of the fan segment and on the outlet air speed of the cooling tower. The result shows that the impact of the natural wind speed on the cooling tower efficiency varies greatly and this impact increases as the wind speed increases.

Qin, Yongbo; Gu, Hongfang; Wang, Haijun; Chen, Guoyong

2013-07-01

52

A practical application combining wireless sensor networks and Internet of Things: Safety Management System for Tower Crane Groups.  

PubMed

The so-called Internet of Things (IoT) has attracted increasing attention in the field of computer and information science. In this paper, a specific application of IoT, named Safety Management System for Tower Crane Groups (SMS-TC), is proposed for use in the construction industry field. The operating status of each tower crane was detected by a set of customized sensors, including horizontal and vertical position sensors for the trolley, angle sensors for the jib and load, tilt and wind speed sensors for the tower body. The sensor data is collected and processed by the Tower Crane Safety Terminal Equipment (TC-STE) installed in the driver's operating room. Wireless communication between each TC-STE and the Local Monitoring Terminal (LMT) at the ground worksite were fulfilled through a Zigbee wireless network. LMT can share the status information of the whole group with each TC-STE, while the LMT records the real-time data and reports it to the Remote Supervision Platform (RSP) through General Packet Radio Service (GPRS). Based on the global status data of the whole group, an anti-collision algorithm was executed in each TC-STE to ensure the safety of each tower crane during construction. Remote supervision can be fulfilled using our client software installed on a personal computer (PC) or smartphone. SMS-TC could be considered as a promising practical application that combines a Wireless Sensor Network with the Internet of Things. PMID:25196106

Zhong, Dexing; Lv, Hongqiang; Han, Jiuqiang; Wei, Quanrui

2014-01-01

53

Vibration Based Wind Turbine Tower Foundation Design Utilizing Soil-Foundation-Structure Interaction  

NASA Astrophysics Data System (ADS)

Wind turbines have been used to generate electricity as an alternative energy source to conventional fossil fuels. This case study is for multiple wind towers located at different villages in Alaska where severe arctic weather conditions exist. The towers are supported by two different types of foundations; large mat or deep piles foundations. Initially, a Reinforced Concrete (RC) mat foundation was utilized to provide the system with vertical and lateral support. Where soil conditions required it, a pile foundation solution was devised utilizing a 30? thick RC mat containing an embedded steel grillage of W18 beams supported by 20?-24? grouted or un-grouted piles. The mixing and casting of concrete in-situ has become the major source of cost and difficulty of construction at these remote Alaska sites. An all-steel foundation was proposed for faster installation and lower cost, but was found to impact the natural frequencies of the structural system by significantly softening the foundation system. The tower-foundation support structure thus became near-resonant with the operational frequencies of the wind turbine leading to a likelihood of structural instability or even collapse. A detailed 3D Finite-Element model of the original tower-foundation-pile system with RC foundation was created using SAP2000. Soil springs were included in the model based on soil properties obtained from the geotechnical consultant. The natural frequency from the model was verified against the tower manufacturer analytical and the experimental values. Where piles were used, numerous iterations were carried out to eliminate the need for the RC and optimize the design. An optimized design was achieved with enough separation between the natural and operational frequencies to prevent damage to the structural system eliminating the need for any RC encasement to the steel foundation or grouting to the piles.

Al Satari, P. E. Mohamed; Hussain, S. E. Saif

2008-07-01

54

Structural health monitoring of wind towers: remote damage detection using strain sensors  

NASA Astrophysics Data System (ADS)

Exploiting wind energy in complex sites like mountain terrains implies the necessity for remote structural health monitoring of the wind towers. In fact, such slender vertical structures exposed to wind may experience large vibrations and repeated stress cycles leading to fatigue cracking. Possible strategies for remote fatigue damage detection are investigated. Specifically, this paper is focused on the use of suitable strain sensors for crack detection in critical sites of the structure, suggesting several strategies taking into account the possibility of wind direction changes and/or wind calm phases. They are based on a radial arrangement of strain sensors around the tower periphery in the vicinity of the base weld joint. The most promising strategy uses the strain difference between adjacent strain sensors as an index of the presence of a crack. The number of sensors to be installed is dictated by the minimum crack size to be detected, which in turn depends on the expected extreme wind conditions and programmed inspection/repair schedule for the structure.

Benedetti, M.; Fontanari, V.; Zonta, D.

2011-05-01

55

Evidence of a Threshold Wind Speed in Tower-mounted Scatterometer Data David W. Draper and David G. Long  

E-print Network

. Evidence of the threshold wind speed and a hysteresis effect have been observed in airship and wave tank in airship data [2]. YSCAT, an ultra-wideband (2-14 GHz) tower-mounted scat- terometer, provides significant

Long, David G.

56

A method to avoid negative damped low frequent tower vibrations for a floating, pitch controlled wind turbine  

NASA Astrophysics Data System (ADS)

Wind turbines mounted on floating platforms is subjected to completely different and soft foundation properties, than seen for onshore wind turbines. This leads to much lower natural frequencies, related to the rigid body motion of the structure which again leads to an unfavorable coupling between tower motion and the pitch control of the turbine. The tower motion in combination with the aerodynamics and the pitch control will be poor or even negative damped which causes large transient loads if not accounted for. The reason for this low damping is shown to be caused by a too fast pitch regulation compared to the motion of the tower or in other words the lowest control-structure natural frequency must be lower than the lowest critical tower frequency. A control algorithm is presented including the tuning method (pole-placement) to ensure the desired control frequency which provides stable tower vibration modes.

Larsen, T. J.; Hanson, T. D.

2007-07-01

57

An evaluation of 915-MHz radar wind profiler/RASS by tower and sodar measurements  

NASA Astrophysics Data System (ADS)

The accuracy and precision of the 915-MHz low-atmosphere wind profiler/RASS have been investigated through comparisons with other better-understood instruments such as rawinsonde (Strauch et al., 1987 and May et al., 1989), sodar (Neff and Wilczak, 1993), and tower instruments (Ye et al., 1993). These studies have provided useful information as well as confidence in the performance of this new technology in boundary-layer research and monitoring. However, because the accuracy of the profiler/RASS measurements depends to a large degree on the strength and homogeneity of small-scale turbulence and the amount of moisture in the atmosphere, the performance of the profiler may change significantly from one environment to another. As the radar wind profiler/RASS technology becomes more widely applied to a variety of research applications and moves toward operational wind, temperature, and eventually flux profiling, it is crucial to quantify its performance under different environmental and meteorological conditions. South-central Washington is a semi-arid shrub-steppe environment with an average annual precipitation of only about 15 cm, which is significantly different from the other locations where comparative studies have been conducted. The performance of the RADIAN 915-MHz wind profiler/RASS in such an environment was evaluated using data from standard instruments mounted on a 120-m meteorological tower and a nearby sodar at the Hanford Meteorological Station. The results of this evaluation are presented in this paper.

Zhong, S.; Shaw, W. J.; Hubbe, J. M.

1994-08-01

58

Investigation of flow characteristics of a single and two-adjacent natural draft dry cooling towers under cross wind condition  

NASA Astrophysics Data System (ADS)

Wind effect on natural draught cooling towers has a very complex physics. The fluid flow and temperature distribution around and in a single and two adjacent (tandem and side by side) dry-cooling towers under cross wind are studied numerically in the present work. Cross-wind can significantly reduce cooling efficiency of natural-draft dry-cooling towers, and the adjacent towers can affect the cooling efficiency of both. In this paper we will present a complex computational model involving more than 750,000 finite volume cells under precisely defined boundary condition. Since the flow is turbulent, the standard k-? turbulence model is used. The numerical results are used to estimate the heat transfer between radiators of the tower and air surrounding it. The numerical simulation explained the main reason for decline of the thermo-dynamical performance of dry-cooling tower under cross wind. In this paper, the incompressible fluid flow is simulated, and the flow is assumed steady and three-dimensional.

Mekanik, Abolghasem; Soleimani, Mohsen

2007-11-01

59

Windmill tower  

SciTech Connect

A windmill tower supports a propeller and a platform that in turn supports a propeller feather control system and a generator system. The entire tower rotates at its base under changes in wind direction so the rotating propeller is constantly maintained upwind of the tower. The tower is a rigid structure that withstands cyclic thrust and torque loading sufficiently to reduce resonant vibrations of the tower as the propeller rotates under the influence of the wind. The resonant frequency of the tower can be higher than the passing frequency of the rotating propeller blades. The tower includes a pair of generally upright fore legs that converge upwardly toward a first apex on the propeller axis of rotation near the front of the platform immediately behind the propeller hub. A diagonal bracing strut extends downwardly from the first apex away from the plane of the fore legs and toward the rear of the tower. The bottoms of the fore legs and the diagonal bracing strut are rigidly interconnected by base plane truss members. A pair of upwardly converging aft legs extend diagonally upwardly from the bottoms of the fore legs toward a second apex aft of the first apex at the rear of the platform. At regular vertical intervals, stiffening trusses add rigidity to the main upright members of the tower structure. The natural frequency of the tower is raised by the fore legs and the diagonal bracing strut being interconnected in a rigid base plane truss. The diagonal bracing strut resists thrust loading on the tower, and the fore legs and aft legs resist torsional forces produced at the top of the tower.

Schachle, C.; Schachle, E.C.; Schachle, J.R.; Schachle, P.J.

1982-04-06

60

The PNL single-tower measurement model of rotationally sampled turbulent wind, with user's guide for STRS2PC  

SciTech Connect

This report describes a single-tower rotationally sampled wind model, STRS-2, that approximates a set of time series of turbulent wind experienced by individual points rotating in circles in a crosswind plane using measurements from anemometers arrayed vertically along a single line. The purposes of the model are (1) to use turbulence measurements made economically from conventional single-tower arrays of anemometers, (2) to incorporate measures characteristics of the wind at specific sites under consideration for operation of wind turbines, spanning the height range if interest, and (3) to estimate the unmeasured turbulence characteristics in the crosswind plane that spans the disk of the rotor blades. 17 refs., 15 figs., 5 tabs.

Connell, J.R.; Morris, V.R.; Powell, D.C.; Gower, G.L.

1988-06-01

61

Feasibility of in situ blade deflection monitoring of a wind turbine using a laser displacement sensor within the tower  

NASA Astrophysics Data System (ADS)

With the potential of commercially viable global wind power, the use of wind energy is expected to rise further, along with related problems. One issue is collision of the wind turbine blades with the tower during operation. Structural health monitoring is required to improve operational safety, minimize the risk of sudden failure or total breakdown, ensure reliable power generation, and reduce wind turbine life cycle costs. To this end, large numbers of sensors such as fiber Bragg grating and piezoelectric devices have been attached to the structure, which is uneconomical and impractical for large wind turbines. This study proposes a single laser displacement sensor (LDS) system in which all of the rotating blades can be cost-effectively evaluated. In contrast to the approach of blade sensor installation, the LDS system is installed in the tower to enable noncontact blade displacement monitoring. The concept of a noncontact sensor and actuator and their energy delivery device installed in the tower will enable various approaches for wind turbine structural health monitoring. Blade bolt loosening can cause deflection in an affected blade. Similarly, nacelle tilt or mass loss damage in a blade can result in changes in blade deflection, but the proposed system can detect such problems early on.

Lee, Jung-Ryul; Kim, Hyeong-Cheol

2013-02-01

62

78 FR 10210 - Utility Scale Wind Towers From China and Vietnam  

Federal Register 2010, 2011, 2012, 2013, 2014

...2011, following receipt of a petition filed with the Commission and Commerce by Broadwind Towers, Inc., Manitowoc, WI; DMI Industries, Fargo, ND; Katana Summit LLC, Columbus, NE; and Trinity Structural Towers, Inc., Dallas, TX. The...

2013-02-13

63

77 FR 9700 - Utility Scale Wind Towers From China and Vietnam  

Federal Register 2010, 2011, 2012, 2013, 2014

...On December 29, 2011, a petition was filed with the Commission and Commerce by Broadwind Towers, Inc., Manitowoc, WI; DMI Industries, Fargo, ND; Katana Summit LLC, Columbus, NE; and Trinity Structural Towers, Inc., Dallas, TX,...

2012-02-17

64

77 FR 805 - Utility Scale Wind Towers From China and Vietnam; Institution of Antidumping and Countervailing...  

Federal Register 2010, 2011, 2012, 2013, 2014

...investigations are being instituted in response to a petition filed on December 29, 2011, by Broadwind Towers, Inc., Manitowoc, WI; DMI Industries, Fargo, ND; Katana Summit LLC, Columbus, NE; and Trinity Structural Towers, Inc., Dallas, TX....

2012-01-06

65

Newspaper Tower  

NSDL National Science Digital Library

Student groups are challenged to design and construct model towers out of newspaper. They are given limited supplies including newspaper, tape and scissors, paralleling the real-world limitations faced by engineers, such as economic restrictions as to how much material can be used in a structure. Students aim to build their towers for height and stability, as well as the strength to withstand a simulated lateral "wind" load.

Techtronics Program

66

Design, fabrication, and initial test of a fixture for reducing the natural frequency of the Mod-O wind turbine tower  

NASA Technical Reports Server (NTRS)

It was desired to observe the behavior of a two bladed wind turbine where the tower first bending natural frequency is less than twice the rotor speed. The system then passes through resonance when accelerating to operating speed. The frequency of the original Mod-O tower was reduced by placing it on a spring fixture. The fixture is adjustable to provide a range of tower bending frequencies. Fixture design details are given and behavior during initial operation is described.

Winemiller, J. R.; Sullivan, T. L.; Sizemore, R. L.; Yee, S. T.

1979-01-01

67

Tower Mesonetwork Climatology and Interactive Display Tool  

NASA Technical Reports Server (NTRS)

Forecasters at the 45th Weather Squadron and Spaceflight Meteorology Group use data from the tower network over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) to evaluate Launch Commit Criteria, and issue and verify forecasts for ground operations. Systematic biases in these parameters could adversely affect an analysis, forecast, or verification. Also, substantial geographical variations in temperature and wind speed can occur under specific wind directions. To address these concerns, the Applied Meteorology Unit (AMU) developed a climatology of temperatures and winds from the tower network, and identified the geographical variation and significant tower biases. The mesoclimate is largely driven by the complex land-water interfaces across KSC/CCAFS. Towers with close proximity to water typically had much warmer nocturnal temperatures and higher wind speeds throughout the year. The strongest nocturnal wind speeds occurred from October to March whereas the strongest mean daytime wind speeds occurred from February to May. These results of this project can be viewed by forecasters through an interactive graphical user interface developed by the AMU. The web-based interface includes graphical and map displays of mean, standard deviation, bias, and data availability for any combination of towers, variables, months, hours, and wind directions.

Case, Jonathan L.; Bauman, William H., III

2004-01-01

68

Comparison of winds, waves, and turbulence as observed by airborne lidar, ground-based radars, and instrumented tower  

NASA Technical Reports Server (NTRS)

On June 29, 1981, two ground-based Doppler radars, an airborne Doppler optical radar (lidar), an instrumented tower, and a rawinsonde were employed to collect wind data in the planetary boundary layer (PBL) in central Oklahoma. The main objectives of this experiment were related to a comparison of wind estimates and the visualization of the three-dimensional eddy structure in the convective atmospheric boundary layer. Discrepancies in the mean wind and wind profile detected by the different sensing systems were explained as being caused by a Schuler resonance of the aircraft's inertial navigation system, which caused an erroneous component of the aircraft's ground-relative velocity vector to be subtracted from the lidar-measured radial velocities. It is concluded that NASA's airborne Doppler optical radar system is capable of measuring wind fields in clear air on a smaller scale than was previously available with fixed remote sensors.

Eilts, M. D.; Doviak, R. J.; Sundara-Rajan, A.

1984-01-01

69

Reliability Evaluation of Electrical Distribution Networks Containing Multiple Overhead Feeders on a Same Tower  

Microsoft Academic Search

Due to the lack of feeder corridors, the Chinese utility companies frequently choose the technique of putting multiple overhead feeders on a same tower (MFST) to meet the load de- mand in a heavy load area. In many situations, the distance among the feeders of MFST in an electrical distribution network (EDN) is usually too small to meet the requirements

Kaigui Xie; Kan Cao; David C. Yu

2011-01-01

70

Effect of rotor configuration on guyed tower and foundation designs and estimated costs for intermediate site horizontal axis wind turbines  

NASA Astrophysics Data System (ADS)

Three designs of a guyed cylindrical tower and its foundation for an intermediate size horizontal axis wind turbine generator are discussed. The primary difference in the three designs is the configuration of the rotor. Two configurations are two-blade rotors with teetering hubs - one with full span pitchable blades, the other with fixed pitch blades. The third configuration is a three-bladed rotor with a rigid hub and fixed pitch blades. In all configurations the diameter of the rotor is 38 meters and the axis of rotation is 30.4 meters above grade, and the power output is 200 kW and 400 kW. For each configuration the design is based upon for the most severe loading condition either operating wind or hurricane conditions. The diameter of the tower is selected to be 1.5 meters (since it was determined that this would provide sufficient space for access ladders within the tower) with guy rods attached at 10.7 meters above grade. Completing a design requires selecting the required thicknesses of the various cylindrical segments, the number and diameter of the guy rods, the number and size of soil anchors, and the size of the central foundation. The lower natural frequencies of vibration are determined for each design to ensure that operation near resonance does not occur. Finally, a cost estimate is prepared for each design. A preliminary design and cost estimate of a cantilever tower (cylindrical and not guyed) and its foundation is also presented for each of the three configurations.

Frederick, G. R.; Winemiller, J. R.; Savino, J. M.

1982-03-01

71

Effect of rotor configuration on guyed tower and foundation designs and estimated costs for intermediate site horizontal axis wind turbines  

NASA Technical Reports Server (NTRS)

Three designs of a guyed cylindrical tower and its foundation for an intermediate size horizontal axis wind turbine generator are discussed. The primary difference in the three designs is the configuration of the rotor. Two configurations are two-blade rotors with teetering hubs - one with full span pitchable blades, the other with fixed pitch blades. The third configuration is a three-bladed rotor with a rigid hub and fixed pitch blades. In all configurations the diameter of the rotor is 38 meters and the axis of rotation is 30.4 meters above grade, and the power output is 200 kW and 400 kW. For each configuration the design is based upon for the most severe loading condition either operating wind or hurricane conditions. The diameter of the tower is selected to be 1.5 meters (since it was determined that this would provide sufficient space for access ladders within the tower) with guy rods attached at 10.7 meters above grade. Completing a design requires selecting the required thicknesses of the various cylindrical segments, the number and diameter of the guy rods, the number and size of soil anchors, and the size of the central foundation. The lower natural frequencies of vibration are determined for each design to ensure that operation near resonance does not occur. Finally, a cost estimate is prepared for each design. A preliminary design and cost estimate of a cantilever tower (cylindrical and not guyed) and its foundation is also presented for each of the three configurations.

Frederick, G. R.; Winemiller, J. R.; Savino, J. M.

1982-01-01

72

Temperatures and stresses due to cement hydration on the R\\/C foundation of a wind tower—A case study  

Microsoft Academic Search

A numerical prediction of temperatures and stresses on a R\\/C foundation of a steel wind tower, and during the first weeks after casting, is presented in this paper. The thermo-mechanical methodology adopted for this kind of analysis is introduced first, describing the thermal field engendered in concrete by the heat released during cement hydration, the aging laws that reproduce the

Miguel Azenha; Rui Faria

2008-01-01

73

Vibration characteristics of a large wind turbine tower on non-rigid foundations  

NASA Technical Reports Server (NTRS)

Vibration characteristics of the Mod-OA wind turbine supported by nonrigid foundations were investigated for a range of soil rigidities. The study shows that the influence of foundation rotation on the fundamental frequency of the wind turbine is quite significant for cohesive soils or loose sand. The reduction in natural frequency can be greater than 20 percent. However, for a foundation resting on well graded, dense granular materials or bedrock, such effect is small and the foundation can be treated as a fixed base.

Yee, S. T.; Cang, T. Y. P.; Scavuzzo, R. J.; Timmerman, D. H.; Fenton, J. W.

1977-01-01

74

Quality-Controlled Wind Data from the Kennedy Space Center 915 Megahertz Doppler Radar Wind Profiler Network  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration s (NASA) Kennedy Space Center (KSC) has installed a five-instrument 915-Megahertz (MHz) Doppler Radar Wind Profiler (DRWP) system that records atmospheric wind profile properties. The purpose of these profilers is to fill data gaps between the top of the KSC wind tower network and the lowest measurement altitude of the KSC 50-MHz DRWP. The 915-MHz DRWP system has the capability to generate three-dimensional wind data outputs from approximately 150 meters (m) to 6,000 m at roughly 15-minute (min) intervals. NASA s long-term objective is to combine the 915-MHz and 50-MHz DRWP systems to create complete vertical wind profiles up to 18,300 m to be used in trajectory and loads analyses of space vehicles and by forecasters on day-of-launch (DOL). This analysis utilizes automated and manual quality control (QC) processes to remove erroneous and unrealistic wind data returned by the 915-MHz DRWP system. The percentage of data affected by each individual QC check in the period of record (POR) (i.e., January to April 2006) was computed, demonstrating the variability in the amount of data affected by the QC processes. The number of complete wind profiles available at given altitude thresholds for each profiler in the POR was calculated and outputted graphically, followed by an assessment of the number of complete wind profiles available for any profiler in the POR. A case study is also provided to demonstrate the QC process on a day of a known weather event.

Dryden, Rachel L.

2011-01-01

75

Windmill tower shadow eliminator  

SciTech Connect

In a wind driven propeller system an airfoil support for the shaft of a propeller having an even number of blades extends above and below the shaft a distance at least equal to the blade length and pivots with the propeller into the wind for substantially eliminating tower shadow effects on the propeller.

Randolph, A.J.

1984-04-17

76

Global Network of Slow Solar Wind N. U. Crooker1  

E-print Network

Global Network of Slow Solar Wind N. U. Crooker1 Center for Space Physics, Boston University of the slow solar wind. Synoptic maps of solar wind speed predicted by the Wang-Sheeley-Arge model during selected periods of solar cycle 23, however, show many areas of slow wind displaced from the streamer belt

Zhao, Xuepu

77

The shape of the Eiffel Tower  

NASA Astrophysics Data System (ADS)

The distinctive shape of the Eiffel Tower is based on simple physics and is designed so that the maximum torque created by the wind is balanced by the torque due to the Tower's weight. We use this idea to generate an equation for the shape of the Tower. The solution depends only on the width of the base and the maximum wind pressure. We parametrize the wind pressure and reproduce the shape of the Tower. We also discuss some of the Tower's interesting history and characteristics.

Gallant, Joseph

2002-02-01

78

Convection towers  

DOEpatents

Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.

Prueitt, M.L.

1996-01-16

79

Convection towers  

DOEpatents

Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

Prueitt, Melvin L. (Los Alamos, NM)

1996-01-01

80

Convection towers  

DOEpatents

Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

Prueitt, Melvin L. (Los Alamos, NM)

1995-01-01

81

Convection towers  

DOEpatents

Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.

Prueitt, Melvin L. (Los Alamos, NM)

1994-01-01

82

The Re-invention of the Tower House for the Construction of Green Buildings NZEB, Integrated With the Vertical Axis Small Wind System  

NASA Astrophysics Data System (ADS)

Nowadays the cultural and economic context aims to create a sustainable "carbon zero" society through energy-efficient green buildings NZEB, but it has so far overlooked a construction type widely spread throughout Europe, especially in the Middle Ages, and that in Italy still characterizes the most beautiful landscapes of Tuscany and other cities: the tower-house. The aim of the research was to verify the possibility of reinventing the type of the familiar tower-house, which is intrinsically directed to conquer the height and therefore higher wind conditions, assuming the installation on the top of a small wind system to use wind energy, to make the building energetically self-sufficient. This building is designed from a wooden structure of a deciduous tree widespread in the Italian region of Basilicata, the Turkish Oak, which, subject to processes of hygrothermal conditioning, can be transformed into the base material to compose laminated timber beams and pillars, able to guarantee a load of exercise, to bending stress, equal to 40.9 N/mm2, as followed by tests in the Laboratory of Engineering of the University of Basilicata, Potenza. With normal wind conditions in the city of Potenza (average of 6.5 m/s), a 5 kW wind turbine mounted at 25 m tall on a 13 m high building is able to provide all the energy the building needs, with its attractive tapered oval top that minimizes turbulence. Entirely made with structures, finishes and natural insulation, the building is a sign in the landscape, history and future together.

Marino, Francesco Paolo R.

83

Neural network based wind speed sensorless MPPT controller for variable speed wind energy conversion systems  

Microsoft Academic Search

A wind speed sensorless neural network (NN) based maximum power point tracking (MPPT) control algorithm for variable speed wind energy conversion system (WECS) is proposed. The proposed method is developed using Jordan type recurrent NN which is trained online using back-propagation. The algorithm, without requiring the knowledge of wind speed, air density or turbine parameters, generates at its output the

J. S. Thongam; P. Bouchard; R. Beguenane; I. Fofana

2010-01-01

84

Tall tower or mountain top measurements?  

NASA Astrophysics Data System (ADS)

Resolving the regional transport and distribution of greenhouse gases in the troposphere is a key topic that challenges both modelers and experimentalists. A dense network of measurement stations would be required, in particular including measurements at high elevation to better represent the entire lower troposphere, and not only small-scale local conditions in the near-surface atmosphere. While this can be achieved by tall towers, also mountain top stations (e.g. Schauinsland, Brocken) and other stations at high elevation (e.g., Mouna Loa, Jungfraujoch) are often appropriate, due to their extended concentration footprint. However, especially over complex, mountainous terrain, the transport of atmospheric gases and their spatio-temporal distribution is difficult to predict due to the development of thermally induced local wind patterns and boundary layer processes. Therefore, the main goal of our study is to test to what extend boundary layer processes at the surface and local wind patterns close to the ground at a mountain top site influence the ambient greenhouse gas patterns compared to measurements taken at a similar altitude but at a tall tower site. To this end we use measurements from the Zugerberg mountain top station, located at a pre-Alpine mountain ridge (987 m a.s.l., 4 m above ground) exposed to the prevailing synoptic winds in Switzerland, and compare these measurements with a neighboring tall tower site (Beromünster radio broadcast tower with its top at 1014 m a.s.l., 217 m above local ground level, and ?500 m above the Swiss Plateau). The Beromünster tall tower is located at a distance of only 30 km from the mountain top station as the bird flies, and hence a direct comparison minimizes confounding factors that are not related to the tall tower vs. mountain top position of the measurements. Both stations are part of the CarboCount CH greenhouse gas observation network (http://www.carbocount.ch) initiated for long-term monitoring and modeling of greenhouse gas fluxes at a regional scale in order to achieve a better understanding about CO2 and CH4 fluxes and their response to climate. We will present first direct comparisons of measurements obtained from continuously calibrated laser absorption spectrometers to quantify the atmospheric concentrations of carbon-dioxide and methane, but also from meteorological sensors and turbulence measurements. Data from the sensors at the two stations will be used to address the following question: can a mountain top station provide similar quality of data and spatial representativeness as a tall tower for the investigation of atmospheric patterns of greenhouse gases at diurnal to seasonal scale?

Bamberger, Ines; Eugster, Werner; Oney, Brian; Brunner, Dominik; Leuenberger, Markus; Schanda, Rüdiger; Henne, Stephan; Buchmann, Nina

2014-05-01

85

South Dakota Wind Resource Assessment Network (WRAN)  

DOE Data Explorer

WRAN is a network of instrument stations sited throughout South Dakota. As of 2010, there are eleven stations, and some have been collecting data since 2001. The purpose of the WRAN:

There are several reasons why the WRAN was built. One of the most obvious is that it will allow verification of the existing resource assessments of our state. South Dakota has tremendous potential as an exporter of wind-generated electricity. There has recently been a great deal of publicity over a Pacific Northwest National Laboratories study conducted in the early 1990s that ranked the contiguous 48 states in terms of their potential to produce windpower. (Click here for the results of this study as given by the American Wind Energy Association.) South Dakota ranked fourth in that study. Also, more recently, detailed maps of the wind resource in South Dakota were produced by the National Renewable Energy Laboratory (NREL). Unfortunately, both of these studies had to rely heavily on computer-generated models and very sparse measured data, because very little appropriate measured data exists. The WRAN will provide valuable data that we anticipate will validate the NREL maps, and perhaps suggest minor adjustments.

There are many other benefits the WRAN will provide. The data it will measure will be at heights above ground that are more appropriate for predicting the performance of large modern wind turbines, as opposed to data collected at National Weather Service stations whose anemometers are usually only about 9 m (30 feet) above ground. Also, we will collect some different types of data than most wind measurement networks, which will allow a series of important studies of the potential impact and value of South Dakota's windpower. In addition, all of the WRAN data will be made available to the public via this WWWeb site. This will hopefully enable extensive informed discussion among all South Dakotans on such important topics as rural economic development and transmission system expansion. [Copied from http://sdwind.com/about/

86

Convection towers  

DOEpatents

Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.

Prueitt, M.L.

1994-02-08

87

Wind power: executive summary on research on network wind power over the Pacific Northwest. Progress report, October 1979-September 1980  

SciTech Connect

This research in FY80 is composed of six primary tasks. These tasks include data collection and analysis, wind flow studies around an operational wind turbine generator (WTG), kite anemometer calibration, wind flow analysis and prediction, the Klickitat County small wind energy conversion system (SWECS) program, and network wind power analysis. The data collection and analysis task consists of four sections, three of which deal with wind flow site surveys and the fourth with collecting and analyzing wind data from existing data stations.

Baker, R.W.; Hewson, E.W.

1980-10-01

88

Balsa Towers  

NSDL National Science Digital Library

Students groups use balsa wood and glue to build their own towers using some of the techniques they learned from the associated lesson. While general guidelines are provided, give students freedom with their designs and encourage them to implement what they have learned about structural engineering. The winning team design is the tower with the highest strength-to-weight ratio.

Techtronics Program

89

A' Brief. History of the Tower Shielding Facility and Tower Shielding Facility  

E-print Network

A' Brief. History of the Tower Shielding Facility and Programs Tower Shielding Facility Hoisting of radiation from reactor. 0 Guyed steel structure 315 feet high 0 Conform to AISC specifications for steel 200 fl with 80 mph wind 0 Two-inch plow steel guys (16) stressed to 75,000 lbs each to minimize tower

90

Evaluation of Mesoscale Modeled East Coast Offshore Winds Using Tall Towers, QuikSCAT, and Buoy Data  

NASA Astrophysics Data System (ADS)

The WRF-ARW version 3.2 mesoscale weather model was used to generate wind fields in the lower planetary boundary layer at high resolution (5 km) for the months of January and July 2008 over the offshore areas of the US East Coast. Three offshore platforms operated by the Skidaway Institute of Oceanography off coastal Georgia with anemometers at the 50 m height were used for validation, as well as surface wind measurements from NDBC buoys and NASA JPL QuikSCAT scatterometer data. The effects of increasing the vertical resolution, allowing for model spin-up, and decreasing the horizontal resolution (to 15 and 45 km) were also examined. This validation is being used as part of a larger East Coast offshore wind energy climatology study that will utilize high resolution mesoscale modeled winds at the turbine hub height of 100 m over five years to predict the long term wind energy potential of that region.

Dvorak, M. J.; Jacobson, M. Z.

2010-12-01

91

Collapsible Towers  

NASA Technical Reports Server (NTRS)

NASA needed a means of orbiting a large radio telescope antenna. Astro Research Corporation developed a new structure that was strong, lightweight, folded into a small storage space, and could be erected by rotation. Later they adapted it to commercial use. Today the "Astromast" tower consists of tubular aluminum alloy and stainless steel members that deploy into small three-sided bays, each made rigid by six diagonal cables. All joints are flexible to permit folding and unfolding. Tower packs into container 5% of its height, can be erected without tools and is reusable. Tower has won "Design of the Year" award from Machine Design. Variations include portable emergency bridges and commercial scaffolding.

1976-01-01

92

Balsa Towers  

NSDL National Science Digital Library

Learners work in groups to design and build a tower out of balsa wood. As a motivator, they can compete to build a tower with the highest strength-to-weight ratio. Learners draw structurally sound 2D designs in the first part of the activity, then use those designs to construct the 3D structure. This activity is best used as a part of a larger lesson or after other building activities. Time for activity can be split over multiple meetings.

Devereaux, Kelly; Burnham, Benjamin

2013-01-01

93

Peak Wind Forecasts for the Launch-Critical Wind Towers on Kennedy Space Center/Cape Canaveral Air Force Station, Phase IV  

NASA Technical Reports Server (NTRS)

This final report describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The peak winds arc an important forecast clement for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to update the statistics in the current peak-wind forecast tool to assist in forecasting LCC violations. The tool includes onshore and offshore flow climatologies of the 5-minute mean and peak winds and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

Crawford, Winifred

2011-01-01

94

Reducing Wind Tunnel Data Requirements Using Neural Networks  

NASA Technical Reports Server (NTRS)

The use of neural networks to minimize the amount of data required to completely define the aerodynamic performance of a wind tunnel model is examined. The accuracy requirements for commercial wind tunnel test data are very severe and are difficult to reproduce using neural networks. For the current work, multiple input, single output networks were trained using a Levenberg-Marquardt algorithm for each of the aerodynamic coefficients. When applied to the aerodynamics of a 55% scale model of a U.S. Air Force/ NASA generic fighter configuration, this scheme provided accurate models of the lift, drag, and pitching-moment coefficients. Using only 50% of the data acquired during, the wind tunnel test, the trained neural network had a predictive accuracy equal to or better than the accuracy of the experimental measurements.

Ross, James C.; Jorgenson, Charles C.; Norgaard, Magnus

1997-01-01

95

Coit Tower  

NSDL National Science Digital Library

Located on top of Telegraph Hill, Coit Tower was the result of a significant donation by Lillie Coit in the 1920s and the ingenuity of the New Deal program initiated by President Franklin Delano Roosevelt. When Lillie Coit passed away in 1929, she left substantial donations to a number of institutions, including the city and county of San Francisco. Shortly after this gift, plans were made to create a memorial to Coit on Telegraph Hill in the form of a single elegant tower. Of course, when the structure was finished, it was largely unadorned on the inside. This situation was soon changed, as a number of artists employed under the auspices of the Public Works Art Project began to work on a number of lovely frescoes depicting scenes from California history. On this site, visitors can learn about the history of Coit Tower, and also view the remarkable works of art that are located within the structure.

Bisson, Mimi.; Geier, Doug.; Martinez, Augustine.; Schneider, Andrea.

96

Global Network of Slow Solar Wind  

NASA Technical Reports Server (NTRS)

The streamer belt region surrounding the heliospheric current sheet (HCS) is generally treated as the primary or sole source of the slow solar wind. Synoptic maps of solar wind speed predicted by the Wang-Sheeley-Arge model during selected periods of solar cycle 23, however, show many areas of slow wind displaced from the streamer belt. These areas commonly have the form of an arc that is connected to the streamer belt at both ends. The arcs mark the boundaries between fields emanating from different coronal holes of the same polarity and thus trace the paths of belts of pseudostreamers, i.e., unipolar streamers that form over double arcades and lack current sheets. The arc pattern is consistent with the predicted topological mapping of the narrow open corridor or singular separator line that must connect the holes and, thus, consistent with the separatrix-web model of the slow solar wind. Near solar maximum, pseudostreamer belts stray far from the HCS-associated streamer belt and, together with it, form a global-wide web of slow wind. Recognition of pseudostreamer belts as prominent sources of slow wind provides a new template for understanding solar wind stream structure, especially near solar maximum.

Crooker, N. U.; Antiochos, S. K.; Zhao, X.; Neugebauer, M.

2012-01-01

97

Vortex-augmented cooling tower - windmill combination  

DOEpatents

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.

McAllister, J.E. Jr.

1982-09-02

98

Tokyo Tower  

E-print Network

with a certain pop celebrity cach?: Godzilla destroyed it in one film, Mothra used it as a nest in another, and the psychic Uri Geller once bounced telekinetic rays off it to bend spoons and fix broken clocks all over Tokyo. Who knows what else the Tower...

Hacker, Randi; Tsutsui, William; Ashworth, William

2007-01-03

99

Magnet Tower  

NSDL National Science Digital Library

In this activity, learners build magnetic towers to explore the forces and properties of magnets. This activity allows learners to experiment and play with magnets and feel first-hand the force of magnets pushing and pulling. Note: this activity requires the use of a drill and saw, which are not included in the cost of materials.

Workshop, Mission S.

2013-01-01

100

Experimental investigation of the dynamic installation of a slip joint connection between the monopile and tower of an offshore wind turbine  

NASA Astrophysics Data System (ADS)

The failure of the traditional grouted connections of offshore wind turbines has led to the investigation of alternatives that provide a connection between the foundation pile and the turbine tower. An alternative to the traditional joint is a steel-to-steel connection also called a slip joint. To ensure a proper fit of the slip joint a dynamic installation of the joint is proposed. In this contribution, the effectiveness of harmonic excitation as an installation procedure is experimentally investigated using a 1:10 scaled model of the joint. During the dynamic installation test the applied static load, settlements and dynamic response of the joint are monitored using respectively load cells, taut wires and strain gauges placed both inside and outside the conical surfaces. The results show that settlement occurs only when applying a harmonic load at specific forcing frequencies. The settlement stabilizes to a certain level for each of the specific frequencies, indicating that a controlled way of installation is possible. The results show that it is essential to vibrate at specific frequencies and that a larger amplitude of the harmonic force does not automatically lead to additional settlement.

Segeren, M. L. A.; Hermans, K. W.

2014-06-01

101

Strategies to design and place towers for long-term ecological observations at continental scale  

NASA Astrophysics Data System (ADS)

There are numerous tower-based measurements applied in ecological science worldwide. National Ecological Observatory Network (NEON) is designing a tower-based method at 60 sites continental wide to measure abiotic drivers of ecological change, carbon and energy fluxes, and to specifically provide ecological connectively to measurements of organism ecology and connectively to remote sensed data products. Several issues come to bear when designing an infrastructure that has to accommodate different suites of measurements that have various requirements, i.e., micrometeorological, scalar flux measurements, atmospheric chemistry and boundary layer properties, and have to be objectively placed across the entire range of climate and ecosystem structures found in North America. Here, we present a comprehensive strategy that combines wind roses, footprint models, ecosystem structure, vegetation and soil maps, as well as ‘eyes on’ site visits to design and place a tower. This methodology is being used to examine the 60 preliminary tower designs in the largest ecological observatory in the world today to optimize the long-term representative measurements over the ecosystems of interests. We found that some preliminary site designs do not meet our tower science requirements due to an inadequate fetch for prevailing wind directions, extent of ecosystems boundaries, or concerns of edge effects. In these cases, the tower location shall be either micro-sited at the current locale, or moved and relocated to a different site altogether. After site specific characterization, we also found that some designed tower heights could not access the well mixed surface layer above canopy and had to be extended in design. Because wind comes from all direction at some sites, presents a particular challenge to orient a square tower. In all cases, we optimized the tower orientation to acquire the most amounts of valid data. To avoid the effects of flow distortion on measurements, the boom length (for sensor mounts) is determined to be 2-3 times of the face width of the tower on the windward side of tower. The measurement levels and heights on a tower are determined by the ecosystem type, canopy and strata. At least 4 measurement levels are expected for short statue ecosystem like grasslands, agricultural land, and prairies, whereas, 6-8 levels are expected for tall forest ecosystems.

Luo, H.; Loescher, H. W.; Ayres, E.; Clement, R.

2010-12-01

102

Structural Monitoring of Wind Turbines using Wireless Sensor Networks  

E-print Network

1 Structural Monitoring of Wind Turbines using Wireless Sensor Networks R. Andrew Swartz1 , Jerome years, low-cost wireless sensors have emerged as an enabling technology for just such monitoring applications. Inexpensive and flexible wireless sensors can be installed within a large structure to measure

Sweetman, Bert

103

Fourth International Workshop on Large-Scale Integration of Wind Power and Transmission Networks for Offshore Wind Farms,  

E-print Network

. Basically, the choice is between focusing on predicting the energy content of the wind and focusing1 Fourth International Workshop on Large-Scale Integration of Wind Power and Transmission Networks for Offshore Wind Farms, 20-21 October 2003, Billund, Denmark C. S. Nielsen, Hans F. Ravn, Camilla Schaumburg

104

Network Wind Power Over the Pacific Northwest. Progress Report, October 1979-September 1980.  

SciTech Connect

The research in FY80 is composed of six primary tasks. These tasks include data collection and analysis, wind flow studies around an operational wind turbine generator (WTG), kite anemometer calibration, wind flow analysis and prediction, the Klickitat County small wind energy conversion system (SWECS) program, and network wind power analysis. The data collection and analysis task consists of four sections, three of which deal with wind flow site surveys and the fourth with collecting and analyzing wind data from existing data stations. This report also includes an appendix which contains mean monthly wind speed data summaries, wind spectrum summaries, time series analysis plots, and high wind summaries.

Baker, Robert W.; Hewson, E. Wendell

1980-10-01

105

Virtual Tower  

SciTech Connect

The primary responsibility of an intrusion detection system (IDS) operator is to monitor the system, assess alarms, and summon and coordinate the response team when a threat is acknowledged. The tools currently provided to the operator are somewhat limited: monitors must be switched, keystrokes must be entered to call up intrusion sensor data, and communication with the response force must be maintained. The Virtual tower is an operator interface assembled from low-cost commercial-off-the-shelf hardware and software; it enables large amounts of data to be displayed in a virtual manner that provides instant recognition for the operator and increases assessment accuracy in alarm annunciator and control systems. This is accomplished by correlating and fusing the data into a 360-degree visual representation that employs color, auxiliary attributes, video, and directional audio to prompt the operator. The Virtual Tower would be a valuable low-cost enhancement to existing systems.

Wayne, R.A. [Sandia National Labs., Albuquerque, NM (United States). Security Engineering Dept.

1997-08-01

106

Surface and Tower Meteorological Instrumentation at NSA Handbook - January 2006  

SciTech Connect

The Surface and Tower Meteorological Instrumentation at Atqasuk (METTWR2H) uses mainly conventional in situ sensors to measure wind speed, wind direction, air temperature, dew point and humidity mounted on a 10-m tower. It also obtains barometric pressure, visibility, and precipitation data from sensors at or near the base of the tower. In addition, a Chilled Mirror Hygrometer is located at 1 m for comparison purposes. Temperature and relative humidity probes are mounted at 2 m and 5 m on the tower. For more information, see the Surface and Tower Meteorological Instrumentation at Atqasuk Handbook.

MT Ritsche

2006-01-30

107

A new UK Greenhouse Gas measurement network providing ultra high-frequency measurements of key radiatively active trace gases taken from a network of tall towers  

NASA Astrophysics Data System (ADS)

Monitoring of atmospheric concentrations of gases is important in assessing the impact of international policies related to the atmospheric environment. The effects of control measures on greenhouse gases introduced under the Montreal and Kyoto Protocols are now being observed. Continued monitoring is required to assess the overall success of the Protocols. For over 15 years the UK Government have funded high-frequency measurements of greenhouse gases and ozone depleting gases at Mace Head, a global background measurement station on the west coast of Ireland. These continuous, high-frequency, high-precision measurements are used to estimate regional (country-scale) emissions of greenhouse gases across the UK using an inversion methodology (NAME-Inversion) that links the Met Office atmospheric dispersion model (Numerical Atmospheric dispersion Modelling Environment - NAME) with the Mace Head observations. This unique inversion method acts to independently verify bottom up emission estimates of radiatively active and ozone-depleting trace gases. In 2011 the UK government (DECC) funded the establishment and integration of three new tall tower measurements stations in the UK, to provide enhanced resolution emission maps and decrease uncertainty of regional emission estimates produced using the NAME-Inversion. One station included in this new UK network was already established in Scotland and was used in collaboration with Edinburgh University. The two other new stations are in England and were set-up early in 2012, they contain brand new instrumentation for measurements of greenhouse gases. All three additional stations provide ultra high-frequency (1 sec) data of CO2 and CH4 using the Picarro© Cavity Ring Down Spectrometer and high frequency (20 min) measurements of N2O and SF6 from custom built sample modules with GC-ECD. We will present the new tall tower UK measurement network in detail. Using high-frequency measurements at new operational sites, including Mace Head, we will present the latest inversion results from the new network highlighting the enhanced resolution in regional emission maps for the UK. These results are presented to the UK government periodically and provide independent verification of the emission estimates of radiatively active trace gases. These results also inform policy makers on the accuracy of inventory emissions estimates of radiatively active and ozone-depleting trace gases.

Grant, A.; O'Doherty, S.; Manning, A. J.; Simmonds, P. G.; Derwent, R. G.; Moncrieff, J. B.; Sturges, W. T.

2012-04-01

108

Techno-economic Optimization of Integrating Wind Power into Constrained Electric Networks  

E-print Network

Techno-economic Optimization of Integrating Wind Power into Constrained Electric Networks by Jesse-economic Optimization of Integrating Wind Power into Constrained Electric Networks by Jesse David Maddaloni B-carbon energy sources such as wind and small-scale hydroelectric power. Models generally employ only a simple

Victoria, University of

109

Neural-network-based sensorless maximum wind energy capture with compensated power coefficient  

Microsoft Academic Search

This paper describes a small wind generation system where neural network principles are applied for wind speed estimation and robust control of maximum wind power extraction against potential drift of wind turbine power coefficient curve. The new control system will deliver maximum electric power to a customer with light weight, high efficiency, and high reliability without mechanical sensors. The concept

Hui Li; K. L. Shi; P. G. McLaren

2005-01-01

110

Wind electric plant  

Microsoft Academic Search

A multiblade, wind-driven, variable pitch propeller is used in a wind electric plant for the generation of electrical power from wind forces, and the propeller is rotatable in a plane at an angle to the tower axis, enabling larger propellers to be used without propeller-tower interference and also reducing the distance between the propeller and gear case. A snubber arrangement

M. L. Jacobs; P. R. Jacobs

1978-01-01

111

Cooling tower  

SciTech Connect

This patent describes a cooling tower comprising: an outer structure composed of a side wall and a top cover; the top cover having an opening on its center with a deflection device for reducing re-circulation of air within the housing; a motor which is fixed in a motor seat and whose shaft forms a spindle which rotates a rotatable cylinder; a rotatable cylinder having sides which have a plurality of small apertures, a centrifugal fan being an integral part of the rotating cylinder, the bottom portion of the cylinder engaging the shaft of the motor, the centrifugal fan comprising: a first flange on the top portion, a second flange on the portion with apertures, a plurality of blades which are equally spaced and fixed between the first and second flanges; a screen positioned concentrically around the rotatable cylinder and secured onto the inside of the top cover of the outer structure, the screen comprising a net and a frame, the frame further comprising a flange and skirt, the frame being secured onto the inside of the top cover of the outer structure with the flange, the skirt extending upwards and inwards through the bottom portion of the rotatable cylinder, the net adherent to the frame.

Liu, W.H.

1987-08-18

112

1 1 1 1 1 1 2 2 Network of offshore wind farms connected by  

E-print Network

2 33 3 3 1 1 1 1 1 1 2 2 Network of offshore wind farms connected by gas insulated transmission, Germany Corresponding author: anja.drews@forwind.de Offshore wind parks in different stages.Green- in op - unknown Source:Siemens Cross-section of a GIL (one of three phases) 1 Future offshore wind power What

Heinemann, Detlev

113

Transient Studies in Large Offshore Wind Farms, Taking Into Account Network Breaker Interaction  

E-print Network

Transient Studies in Large Offshore Wind Farms, Taking Into Account Network Breaker Interaction studies in offshore wind farms, PSCAD. I. INTRODUCTION IN OWF applications, the consequences of component) are considered a pos- sible source of experienced component failures in existing off- shore wind farms (OWFs

Bak, Claus Leth

114

Output prediction of wind power generation system using complex-valued neural network  

Microsoft Academic Search

In this paper, we proposed an output prediction system of a wind power generation using a complex-valued neural network (called here, CVNN). The CVNN is suitable for treating complex numbers and nonlinear data. Then we express the wind information (wind speed and direction) by complex numbers on the complex coordinates, and use them as input information for the CVNN. As

Takahiro Kitajima; Takashi Yasuno

2010-01-01

115

Use of Bayesian networks classifiers for long-term mean wind turbine energy output estimation at a potential wind energy conversion site  

Microsoft Academic Search

Due to the interannual variability of wind speed a feasibility analysis for the installation of a Wind Energy Conversion System at a particular site requires estimation of the long-term mean wind turbine energy output. A method is proposed in this paper which, based on probabilistic Bayesian networks (BNs), enables estimation of the long-term mean wind speed histogram for a site

José A. Carta; Sergio Velázquez; J. M. Matías

2011-01-01

116

Presented on the European Wind Energy Conference & Exhibition, Brussels, Belgium, March, 31 Network of offshore wind farms connected by gas insulated  

E-print Network

­April, 3 rd 2008. Network of offshore wind farms connected by gas insulated transmission lines? Anja Summary The offshore wind power industry faces two major challenges: the connection of wind farms to the high voltage grid onshore and a smart grid integration of this offshore generated wind power. In terms

Heinemann, Detlev

117

Application of Neural Networks to Wind tunnel Data Response Surface Methods  

NASA Technical Reports Server (NTRS)

The integration of nonlinear neural network methods with conventional linear regression techniques is demonstrated for representative wind tunnel force balance data modeling. This work was motivated by a desire to formulate precision intervals for response surfaces produced by neural networks. Applications are demonstrated for representative wind tunnel data acquired at NASA Langley Research Center and the Arnold Engineering Development Center in Tullahoma, TN.

Lo, Ching F.; Zhao, J. L.; DeLoach, Richard

2000-01-01

118

Vortex-augmented cooling tower-windmill combination  

DOEpatents

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.

McAllister, Jr., John E. (Aiken, SC)

1985-01-01

119

Tall Tower Challenge  

NSDL National Science Digital Library

In this activity, learners explore the design of tall structures such as skyscrapers and telecommunication towers. Learners work in teams to engineer the tallest tower they can build using just straws, pipe cleaners, and paperclips. The tower must be strong enough to support the weight of a golf ball for two minutes.

2014-05-22

120

Improvement of Offshore Wind Resource Modeling in the Mid-  

E-print Network

Improvement of Offshore Wind Resource Modeling in the Mid- Atlantic Bight Wind Energy Symposium Sienkiewicz , Chris Hughes 26 February 2013 #12;Improving Atmospheric Models for Offshore Wind Resource Interaction Tower ­ 23 m NOAA Buzzard's Bay Tower ­ 25 m Cape Wind Tower (60 m from 2003-2011; just platform

Firestone, Jeremy

121

Large Amplitude Spatial and Temporal Gradients in Atmospheric Boundary Layer CO2 Mole Fractions Detected With a Tower-Based Network in the U.S. Upper Midwest  

SciTech Connect

This study presents observations of atmospheric CO{sub 2} mole fraction from a nine-tower, regional network deployed during the North American Carbon Program's Mid-Continent Intensive during 2007-2009. Within this network in a largely agricultural area, mean atmospheric CO{sub 2} gradients were strongly correlated with both ground-based inventory data and estimates from satellite remote sensing. The average seasonal drawdown for corn-dominated sites (35 ppm) is significantly larger than has been observed at other continental boundary layer sites. Observed growing-season median CO{sub 2} gradients are strongly dependent on local flux. The gradients between cross-vegetation site-pairs, for example, average 2.0 ppm/100 km, four times larger than the similar-vegetation site-pair average. Daily-timescale gradients are as large as 5.5 ppm/100 km, but dominated by advection rather than local flux. Flooding in 2008 led to a region-wide 23 week delay in growing-season minima. The observations show that regional-scale CO{sub 2} mole fraction networks yield large, coherent signals governed largely by regional sources and sinks of CO{sub 2}.

Miles, Natasha; Richardson, S. J.; Davis, Kenneth J.; Lauvaux, Thomas; Andrews, A.; West, Tristram O.; Bandaru, Varaprasad; Crosson, Eric R.

2012-02-21

122

Climate and vegetation controls on the surface water balance: Synthesis of evapotranspiration measured across a global network of flux towers  

NASA Astrophysics Data System (ADS)

The Budyko framework elegantly reduces the complex spatial patterns of actual evapotranspiration and runoff to a general function of two variables: mean annual precipitation (MAP) and net radiation. While the methodology has first-order skill, departures from a globally averaged curve can be significant and may be usefully attributed to additional controls such as vegetation type. This paper explores the magnitude of such departures as detected from flux tower measurements of ecosystem-scale evapotranspiration, and investigates their attribution to site characteristics (biome, seasonal rainfall distribution, and frozen precipitation). The global synthesis (based on 167 sites with 764 tower-years) shows smooth transition from water-limited to energy-limited control, broadly consistent with catchment-scale relations and explaining 62% of the across site variation in evaporative index (the fraction of MAP consumed by evapotranspiration). Climate and vegetation types act as additional controls, combining to explain an additional 13% of the variation in evaporative index. Warm temperate winter wet sites (Mediterranean) exhibit a reduced evaporative index, 9% lower than the average value expected based on dryness index, implying elevated runoff. Seasonal hydrologic surplus explains a small but significant fraction of variance in departures of evaporative index from that expected for a given dryness index. Surprisingly, grasslands on average have a higher evaporative index than forested landscapes, with 9% more annual precipitation consumed by annual evapotranspiration compared to forests. In sum, the simple framework of supply- or demand-limited evapotranspiration is supported by global FLUXNET observations but climate type and vegetation type are seen to exert sizeable additional controls.

Williams, Christopher A.; Reichstein, Markus; Buchmann, Nina; Baldocchi, Dennis; Beer, Christian; Schwalm, Christopher; Wohlfahrt, Georg; Hasler, Natalia; Bernhofer, Christian; Foken, Thomas; Papale, Dario; Schymanski, Stan; Schaefer, Kevin

2012-06-01

123

Microwave Tower Deflection Monitor  

NASA Astrophysics Data System (ADS)

This paper describes an instrument which is capable of monitoring both the twist and lateral motion of a microwave tower. The Microwave Tower Deflection Monitor (MTDM) gives designers the capability of evaluating towers, both for troubleshooting purposes and comparison with design theory. The MTDM has been designed to operate on a broad range of tower structures in a variety of weather conditions. The instrument measures tower motion by monitoring the position of two retroreflectors mounted on the top of the tower. The two retroreflectors are located by scanning a laser beam in a raster pattern in the vicinity of the reflector. When a retroreflector is struck its position is read by a microprocessor and stored on a magnetic tape. Position resolution of better than .5 cm at 200 ft. has been observed in actual tests.

Truax, Bruce E.

1980-10-01

124

Neuro-fuzzy networks for short-term wind power forecasting  

Microsoft Academic Search

This paper presents a statistical model based on a hybrid computational intelligence technique that merging neural networks and fuzzy logic for wind power forecasting. A mesoscale NWP model is used to forecast meteorological variables at a reference point of a wind farm for the next 36 hours at half-hour intervals. The output of the NWP model, together with measured data

Junrong Xia; Pan Zhao; Yiping Dai

2010-01-01

125

Airport Remote Tower Sensor Systems  

NASA Technical Reports Server (NTRS)

Networks of video cameras, meteorological sensors, and ancillary electronic equipment are under development in collaboration among NASA Ames Research Center, the Federal Aviation Administration (FAA), and the National Oceanic Atmospheric Administration (NOAA). These networks are to be established at and near airports to provide real-time information on local weather conditions that affect aircraft approaches and landings. The prototype network is an airport-approach-zone camera system (AAZCS), which has been deployed at San Francisco International Airport (SFO) and San Carlos Airport (SQL). The AAZCS includes remotely controlled color video cameras located on top of SFO and SQL air-traffic control towers. The cameras are controlled by the NOAA Center Weather Service Unit located at the Oakland Air Route Traffic Control Center and are accessible via a secure Web site. The AAZCS cameras can be zoomed and can be panned and tilted to cover a field of view 220 wide. The NOAA observer can see the sky condition as it is changing, thereby making possible a real-time evaluation of the conditions along the approach zones of SFO and SQL. The next-generation network, denoted a remote tower sensor system (RTSS), will soon be deployed at the Half Moon Bay Airport and a version of it will eventually be deployed at Los Angeles International Airport. In addition to remote control of video cameras via secure Web links, the RTSS offers realtime weather observations, remote sensing, portability, and a capability for deployment at remote and uninhabited sites. The RTSS can be used at airports that lack control towers, as well as at major airport hubs, to provide synthetic augmentation of vision for both local and remote operations under what would otherwise be conditions of low or even zero visibility.

Maluf, David A.; Gawdiak, Yuri; Leidichj, Christopher; Papasin, Richard; Tran, Peter B.; Bass, Kevin

2006-01-01

126

Surface and Tower Meteorological Instrumentation at Atqasuk (METTWR2H) Handbook  

SciTech Connect

The Atqasuk meteorology station (AMET) uses mainly conventional in situ sensors to measure wind speed, wind direction, air temperature, dew point, and humidity mounted on a 10-m tower. It also obtains barometric pressure, visibility and precipitation data from sensors at or near the base of the tower. In addition, a chilled mirror hygrometer (CMH) is located at 1 m for comparison purposes. Temperature and relative humidity (RH) probes are mounted at 2 m and 5 m on the tower.

Ritsche, MT

2006-01-01

127

Research on The Remoter Monitoring and Control System of Transformer Winding Temperature Based on Optical Fiber Networked Sensor  

Microsoft Academic Search

A standard generic network interface was designed for an optical fiber sensor based on CANbus. An advanced method of temperature measurement was adopted for the winding temperature in large power transformers by the networked sensor. It offers a lot of interesting features such as plug & play in the network. The on line supervision system of the winding temperature in

Shiyong Pan; Ping Zheng; Yinlu Ren; Changju Chen; Zihui Shao

2006-01-01

128

Drop Tower Physics  

ERIC Educational Resources Information Center

The drop towers of yesteryear were used to make lead shot for muskets, as described in "The Physics Teacher" in April 2012. However, modern drop towers are essentially elevators designed so that the cable can "break" on demand, creating an environment with microgravity for a short period of time, currently up to nine seconds at…

Dittrich, William A.

2014-01-01

129

Confusion at the Tower  

ERIC Educational Resources Information Center

This study will explore the omission of the Tower of Babel narrative from middle and secondary school world history, world studies, and world geography textbooks and will consider what might be learned from inclusion of the story in the curriculum. A total of 17 textbooks are analyzed. The Tower of Babel narrative is examined within the context of…

Li, Loretta F.

2014-01-01

130

Coastal Ohio Wind Project  

SciTech Connect

The Coastal Ohio Wind Project intends to address problems that impede deployment of wind turbines in the coastal and offshore regions of Northern Ohio. The project evaluates different wind turbine designs and the potential impact of offshore turbines on migratory and resident birds by developing multidisciplinary research, which involves wildlife biology, electrical and mechanical engineering, and geospatial science. Firstly, the project conducts cost and performance studies of two- and three-blade wind turbines using a turbine design suited for the Great Lakes. The numerical studies comprised an analysis and evaluation of the annual energy production of two- and three-blade wind turbines to determine the levelized cost of energy. This task also involved wind tunnel studies of model wind turbines to quantify the wake flow field of upwind and downwind wind turbine-tower arrangements. The experimental work included a study of a scaled model of an offshore wind turbine platform in a water tunnel. The levelized cost of energy work consisted of the development and application of a cost model to predict the cost of energy produced by a wind turbine system placed offshore. The analysis found that a floating two-blade wind turbine presents the most cost effective alternative for the Great Lakes. The load effects studies showed that the two-blade wind turbine model experiences less torque under all IEC Standard design load cases considered. Other load effects did not show this trend and depending on the design load cases, the two-bladed wind turbine showed higher or lower load effects. The experimental studies of the wake were conducted using smoke flow visualization and hot wire anemometry. Flow visualization studies showed that in the downwind turbine configuration the wake flow was insensitive to the presence of the blade and was very similar to that of the tower alone. On the other hand, in the upwind turbine configuration, increasing the rotor blade angle of attack reduced the wake size and enhanced the vortices in the flow downstream of the turbine-tower compared with the tower alone case. Mean and rms velocity distributions from hot wire anemometer data confirmed that in a downwind configuration, the wake of the tower dominates the flow, thus the flow fields of a tower alone and tower-turbine combinations are nearly the same. For the upwind configuration, the mean velocity shows a narrowing of the wake compared with the tower alone case. The downwind configuration wake persisted longer than that of an upwind configuration; however, it was not possible to quantify this difference because of the size limitation of the wind tunnel downstream of the test section. The water tunnel studies demonstrated that the scale model studies could be used to adequately produce accurate motions to model the motions of a wind turbine platform subject to large waves. It was found that the important factors that affect the platform is whether the platform is submerged or surface piercing. In the former, the loads on the platform will be relatively reduced whereas in the latter case, the structure pierces the wave free surface and gains stiffness and stability. The other important element that affects the movement of the platform is depth of the sea in which the wind turbine will be installed. Furthermore, the wildlife biology component evaluated migratory patterns by different monitoring systems consisting of marine radar, thermal IR camera and acoustic recorders. The types of radar used in the project are weather surveillance radar and marine radar. The weather surveillance radar (1988 Doppler), also known as Next Generation Radar (NEXRAD), provides a network of weather stations in the US. Data generated from this network were used to understand general migratory patterns, migratory stopover habitats, and other patterns caused by the effects of weather conditions. At a local scale our marine radar was used to complement the datasets from NEXRAD and to collect additional monitoring parameters such as passage rates, flight paths, flight directi

Gorsevski, Peter; Afjeh, Abdollah; Jamali, Mohsin; Bingman, Verner

2014-04-04

131

Research on A Networked Optical Fiber Temperature Sensor of Large Power transformer windings  

Microsoft Academic Search

A optical fiber temperature sensor was used to measure the temperature of large power transformer windings. A standard generic network interface was designed for the sensor based on IEEE1451. It offers a lot of interesting features such as plug & play in the network. The CAN bus interface module, as transducer independent interface (TIl) was used to connected transducer interface

Ping Zheng; Shiyong Pan; Changju Chen; Yinlu Ren

2006-01-01

132

Wind  

NSDL National Science Digital Library

What part does the wind play in satisfying energy demands? This informational piece, part of a series about the future of energy, introduces students to wind as an energy source. Here students read about the history, uses, and efficiency of wind power. Information is also provided about benefits, limitations, and geographical considerations of wind power in the United States. Thought-provoking questions afford students chances to reflect on what they've read about the uses of wind power. Supplemental articles and information are available from a sidebar. Three energy-related web links are also provided. Copyright 2005 Eisenhower National Clearinghouse

Iowa Public Television. Explore More Project

2004-01-01

133

Drop Tower Physics  

NASA Astrophysics Data System (ADS)

The drop towers of yesteryear were used to make lead shot for muskets, as described in The Physics Teacher1 in April 2012. However, modern drop towers are essentially elevators designed so that the cable can "break" on demand, creating an environment with microgravity for a short period of time, currently up to nine seconds at the drop tower in Bremen, Germany. Using these drop towers, one can briefly investigate various physical systems operating in this near zero-g environment. The resulting "Drop Tower Physics" is a new and exciting way to challenge students with a physical example that requires solid knowledge of many basic physics principles, and it forces them to practice the scientific method. The question is, "How would a simple toy, like a pendulum, behave when it is suddenly exposed to a zero-g environment?" The student must then postulate a particular behavior, test the hypothesis against physical principles, and if the hypothesis conforms to these chosen physical laws, the student can formulate a final conclusion. At that point having access to a drop tower is very convenient, in that the student can then experimentally test his or her conclusion. The purpose of this discussion is to explain the response of these physical systems ("toys") when the transition is made to a zero-g environment and to provide video demonstrations of this behavior to support in-class discussions of Drop Tower Physics.

Dittrich, William A. Toby

2014-10-01

134

View of Nevada rim towers from Arizona side. Left tower ...  

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

View of Nevada rim towers from Arizona side. Left tower supports Circuit 6, middle tower supports Circuit 5, and right tower supports Circuits 4 and 15, view north - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

135

Unavailability of wind turbines due to wind-induced accelerations  

Microsoft Academic Search

The malfunctioning of acceleration-sensitive equipment in wind turbines has the potential to affect their annual failure rates during normal operating conditions. Current protective measures for wind turbines are triggered by wind speed. However, this option neglects the structural response of the wind turbines, and limits the possibility of effectively controlling accelerations at the top of the wind towers. In this

Leonardo Dueñas-Osorio; Biswajit Basu

2008-01-01

136

Tower Camera Handbook  

SciTech Connect

The tower camera in Barrow provides hourly images of ground surrounding the tower. These images may be used to determine fractional snow cover as winter arrives, for comparison with the albedo that can be calculated from downward-looking radiometers, as well as some indication of present weather. Similarly, during spring time, the camera images show the changes in the ground albedo as the snow melts. The tower images are saved in hourly intervals. In addition, two other cameras, the skydeck camera in Barrow and the piling camera in Atqasuk, show the current conditions at those sites.

Moudry, D

2005-01-01

137

Coupled dynamics analysis of wind energy systems  

NASA Technical Reports Server (NTRS)

A qualitative description of all key elements of a complete wind energy system computer analysis code is presented. The analysis system addresses the coupled dynamics characteristics of wind energy systems, including the interactions of the rotor, tower, nacelle, power train, control system, and electrical network. The coupled dynamics are analyzed in both the frequency and time domain to provide the basic motions and loads data required for design, performance verification and operations analysis activities. Elements of the coupled analysis code were used to design and analyze candidate rotor articulation concepts. Fundamental results and conclusions derived from these studies are presented.

Hoffman, J. A.

1977-01-01

138

Wind energy potential in Turkey  

Microsoft Academic Search

Lewis's methods are employed to evaluate the wind energy potentials of four selected locations, which have experienced relatively high wind velocities. In addition to Lewis's methods, the relations connecting the instantaneous and average wind powers, total and maximum wind energies for a given period of time are derived. Characteristics of wind energy, including rotor radius and tower height, are estimated

H. Külünk

1993-01-01

139

Hoover Dam Intake Towers  

USGS Multimedia Gallery

Hoover Dam impounds Lake Mead and provides drinking water and hydroelectric power to the surrounding area. It was constructed between 1931 and 1936. The Intake Towers are where water enters to generate electricity....

140

Cooling Towers Make Money  

E-print Network

COOLING TOWERS MAKE MONEY Robert Burger President ABSTRACT Question:-Why is the low bidder system a sacred cow? If contractors understand, by specifications, that the second low bidder will be awarded the contract all bidders will do... cooling tower designer can use a larger box size and reduce the horsepower 25 to 30%. However this larger box size costs more money than the smaller box. It will have more evaporation fill surface than a smaller box with a higher horsepower motors...

Burger, R.

141

Tower O' Power  

NSDL National Science Digital Library

In this activity, students learn about creating a design directly from a CAD (computer-aided design) program. They will design a tower in CAD and manufacture the parts with a laser cutter. A competition determines the tower design with the best strength:weight ratio. Students also investigate basic structural truss concepts and stress concentrations. Partnership with a local college or manufacturing center is necessary for the completion of this project.

Integrated Teaching And Learning Program

142

Hurricane Frances Rain Towers  

NSDL National Science Digital Library

NASAs TRMM spacecraft allows us to look under Hurricane Frances clouds to see the rain structure. Spikes in the rain structure known as "Hot Towers" indicate storm intensity. The "hot towers" which refers to the tall cumulonimbus, has been seen as one of the mechanisms by which the intensity of a tropical cyclone is maintained. Because of the size (1-5 km) and short duration (30 minute to 2 hours) of these hot towers, studies of these events have been limited to descriptive studies from aircraft observations, although a few have attempted to use the presence of hot towers in a predictive capacity. Before TRMM, no data set exists that can show globally and definitively the presence of these hot towers in cyclone systems. Aircraft radar studies of individual storms lack global coverage. Global microwave or Infrared sensor observations do not provide the needed spatial resolution. With a ground resolution of 5 km, the TRMM Precipitation Radar provided the needed data set for examining the predictive value of hot towers in cyclone intensification.

Perkins, Lori; Halverson, Jeff

2005-04-11

143

Radial basis function network wind tunnel wind speed detection algorithm based on PSO  

Microsoft Academic Search

corresponding model based on PS?. The PSO-RBF network has simple network structure, fast learning methods, good generalization ability. And it compared with other methods as a distinct advantage. Through simulation of MATLAB shows, it has small error that between the measured value of anemometer and simulated value of network of based on PSO-RBF, and obvious advantage over other optimization algorithm.

Chen Baoyuan; Sun Chenlin; Wu Qian; Lin Xirong

2011-01-01

144

Active tower damping and pitch balancing – design, simulation and field test  

NASA Astrophysics Data System (ADS)

The tower is one of the major components in wind turbines with a contribution to the cost of energy of 8 to 12% [1]. In this overview the load situation of the tower will be described in terms of sources of loads, load components and fatigue contribution. Then two load reduction control schemes are described along with simulation and field test results. Pitch Balancing is described as a method to reduce aerodynamic asymmetry and the resulting fatigue loads. Active Tower Damping is reducing the tower oscillations by applying appropiate pitch angle changes. A field test was conducted on an Areva M5000 wind turbine.

Duckwitz, Daniel; Shan, Martin

2014-12-01

145

Surface and Tower Meteorological Instrumentation at Barrow (METTWR4H) Handbook  

SciTech Connect

The Barrow meteorology station (BMET) uses mainly conventional in situ sensors mounted at four different heights (2m, 10m, 20m and 40m) on a 40 m tower to obtain profiles of wind speed, wind direction, air temperature, dew point and humidity. It also obtains barometric pressure, visibility and precipitation data from sensors at the base of the tower. Additionally, a Chilled Mirror Hygrometer and an Ultrasonic wind speed sensor are located near the 2m level for comparison purposes.

Ritsche, MT

2008-04-01

146

Optimizing an infrasound sensor network for measuring acoustic background noise and its inversion for stratospheric winds  

NASA Astrophysics Data System (ADS)

We demonstrate the design of an infrasound network (and the associated analysis) for measuring and inverting low-frequency acoustic background noise (microbaroms) for stratospheric winds. We developed a mathematical framework for the inversion of local stratospheric winds using microbaroms, and found theoretical constraints on the optimum sensor network topology. Based on these results, we deployed, over the winter months (January to March, 2013), a prototype sensor network comprising six infrasound stations separated between 5 and 70 km; the initial analysis shows periods of very high coherency (suitable for our inversion) lasting several hours with associated tropospheric and low stratospheric celerities. We are analyzing the coherency between signals with distance and relative azimuth. Following this pilot study, we are designing a denser sensor network further optimized to capture microbaroms and planning for its validation using independent measurements.

Marcillo, O. E.; Arrowsmith, S.

2013-12-01

147

Wind power. [electricity generation  

NASA Technical Reports Server (NTRS)

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.

Savino, J. M.

1975-01-01

148

Fluid power network for centralized electricity generation in offshore wind farms  

NASA Astrophysics Data System (ADS)

An innovative and completely different wind-energy conversion system is studied where a centralized electricity generation within a wind farm is proposed by means of a hydraulic network. This paper presents the dynamic interaction of two turbines when they are coupled to the same hydraulic network. Due to the stochastic nature of the wind and wake interaction effects between turbines, the operating parameters (i.e. pitch angle, rotor speed) of each turbine are different. Time domain simulations, including the main turbine dynamics and laminar transient flow in pipelines, are used to evaluate the efficiency and rotor speed stability of the hydraulic system. It is shown that a passive control of the rotor speed, as proposed in previous work for a single hydraulic turbine, has strong limitations in terms of performance for more than one turbine coupled to the same hydraulic network. It is concluded that in order to connect several turbines, a passive control strategy of the rotor speed is not sufficient and a hydraulic network with constant pressure is suggested. However, a constant pressure network requires the addition of active control at the hydraulic motors and spear valves, increasing the complexity of the initial concept. Further work needs to be done to incorporate an active control strategy and evaluate the feasibility of the constant pressure hydraulic network.

Jarquin-Laguna, A.

2014-06-01

149

Peak Wind Tool for General Forecasting  

NASA Technical Reports Server (NTRS)

This report describes work done by the Applied Meteorology Unit (AMU) in predicting peak winds at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45th Weather Squadron requested the AMU develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. Based on observations from the KSC/CCAFS wind tower network , Shuttle Landing Facility (SLF) surface observations, and CCAFS sounding s from the cool season months of October 2002 to February 2007, the AMU created mul tiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence , the temperature inversion depth and strength, wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft.

Barrett, Joe H., III; Short, David

2008-01-01

150

2. Keeper's house, light tower, bell tower and supply building, ...  

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

2. Keeper's house, light tower, bell tower and supply building, view north, southwest and southeast sides - Pemaquid Point Light Station, End of State Highway 130 south of Bristol Village, Bristol, Lincoln County, ME

151

9. Supply house, bell tower and light tower, looking north, ...  

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

9. Supply house, bell tower and light tower, looking north, southeast and southwest sides - Pemaquid Point Light Station, End of State Highway 130 south of Bristol Village, Bristol, Lincoln County, ME

152

5. Supply house, bell tower, light tower and keeper's house, ...  

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

5. Supply house, bell tower, light tower and keeper's house, view southwest, northeast sides - Pemaquid Point Light Station, End of State Highway 130 south of Bristol Village, Bristol, Lincoln County, ME

153

1. Keeper's house, light tower, bell tower and supply building, ...  

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

1. Keeper's house, light tower, bell tower and supply building, view north, southwest and southeast sides - Pemaquid Point Light Station, End of State Highway 130 south of Bristol Village, Bristol, Lincoln County, ME

154

3. VIEW NORTHWEST, height finder radar towers, and radar tower ...  

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

3. VIEW NORTHWEST, height finder radar towers, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

155

69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER ...  

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

69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER UNDER CONSTRUCTION. (DATE UNKNOWN). - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

156

26. STATIC TEST TOWER CONTROL PANELS AT REAR OF TOWER ...  

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

26. STATIC TEST TOWER CONTROL PANELS AT REAR OF TOWER UNDERNEATH SHED ROOF. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

157

Direct adaptive control of wind energy conversion systems using Gaussian networks  

Microsoft Academic Search

Grid connected wind energy conversion systems (WECS) present interesting control demands, due to the intrinsic nonlinear characteristics of windmills and electric generators. In this paper a direct adaptive control strategy for WECS control is proposed. It is based on the combination of two control actions: a radial basis function network-based adaptive controller, which drives the tracking error to zero with

Miguel Angel Mayosky; Gustavo I. E. Cancelo

1999-01-01

158

Floating wind turbine system  

NASA Technical Reports Server (NTRS)

A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

Viterna, Larry A. (Inventor)

2009-01-01

159

5. VIEW EAST, height finder radar towers, radar tower (unknown ...  

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

5. VIEW EAST, height finder radar towers, radar tower (unknown function), prime search radar tower, operations building, and central heating plant - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

160

Morpho Towers - Two Standing Spirals  

NSDL National Science Digital Library

This YouTube video by Sachiko Kodama, "Morpho Towers, Two Standing Spirals," shows a ferrofluid work of art. As music plays, the video shows ferrofluid patterns appearing and changing on two towers as electromagnets inside produce changing magnetic fields.

Kodama, Sachiko

2011-11-28

161

Evaporation Tower With Prill Nozzles  

NASA Technical Reports Server (NTRS)

Tower more efficient than conventional evaporation equipment. Liquids such as milk and fruit juice concentrated by passing them through tiny nozzle to form droplets, then allowing droplets to fall through evacuated tower with cooled walls.

Du Fresne, E. R.

1984-01-01

162

Thermal Characteristics of Heating Towers  

NASA Astrophysics Data System (ADS)

Thermal characteristics of heating towers for air-source heat pumps are studied in terms of the overall enthalpy-transfer coefficient. Ka. First. the method of counter-flow calculation is presented taking physical properties of ethylene glycol solutions into account. Next, both cooling-tower and heating-tower experiments are carried out in a small, induced-draft. counterflow tower packed with tubes of a staggerd arrangement. using water and commercial ethylene glycol solutions. The coefficient Ka measured in the heating-tower experiment shows a trend similar to that in the cooling-tower experiment. So. the data on cooling towers will be helpful to the thermal design of heating towers.

Fujita, Toshihiko; Kametani, Shigeki

163

Ivory Basements and Ivory Towers  

ERIC Educational Resources Information Center

The metaphors of the ivory tower and ivory basement are used in this chapter to reflect how many women understand and experience the academy. The ivory tower signifies a place that is protected, a place of privilege and authority and a place removed from the outside world (and consequently the rigours of the market place). The ivory tower, by…

Fitzgerald, Tanya

2012-01-01

164

COOLING TOWER PLUME MODEL  

EPA Science Inventory

A review of recently reported cooling tower plume models yields none that is universally accepted. The entrainment and drag mechanisms and the effect of moisture on the plume trajectory are phenomena which are treated differently by various investigators. In order to better under...

165

Alton Towers “Air”  

Microsoft Academic Search

Shows how a single creative idea provided the platform for communications which were not only genuinely integrated but permeated the business of theme park Alton Towers: this was the launch of the Air ride, and the advertising for it, which enhanced positive attitudes towards the brand, and led to increased visitorship and secondary spend, plus additional revenue from sponsorship. Explores

Lindsay Gregory

2004-01-01

166

Cell Towers and Songbirds  

ERIC Educational Resources Information Center

This article describes how our common addiction to cell phones was used to launch a discussion about their use, impacts on the environment, and connections to issues of civic concern. By encouraging middle school science students to adopt the perspectives of special-interest groups debating communication tower restrictions designed to protect…

Klosterman, Michelle; Mesa, Jennifer; Milton, Katie

2009-01-01

167

A radar-based monitoring of the Collserola tower (Barcelona)  

NASA Astrophysics Data System (ADS)

This paper reports a set of experiments aiming at evaluating the capability of an innovative radar technique to measure the dynamic response of a 268 m high tower, the Collserola tower located in Barcelona, and its guys; the tension force of some guys is also estimated from the obtained vibration frequencies. The applied procedure was based on the use of a coherent radar system: temporal samples acquired using different observation geometries were processed to retrieve the vibration characteristics of both the tower and its guys. This was attained by observing the tower in a fully remote sensing mode, i.e. several hundred metres from the object, without installing any reflector on the tower, and under micro-tremor and wind-induced excitation. During the campaigns, which were spread over three years, the investigated technique demonstrated its capability to measure the dynamic response for a number of different points of the tower with high repeatability. The performed experiments also allowed distinguishing and characterizing the different contributions of the tower and the guys.

Luzi, G.; Crosetto, M.; Cuevas-González, M.

2014-12-01

168

Active Control of Wind-Tunnel Model Aeroelastic Response Using Neural Networks  

NASA Technical Reports Server (NTRS)

NASA Langley Research Center, Hampton, VA 23681 Under a joint research and development effort conducted by the National Aeronautics and Space Administration and The Boeing Company (formerly McDonnell Douglas) three neural-network based control systems were developed and tested. The control systems were experimentally evaluated using a transonic wind-tunnel model in the Langley Transonic Dynamics Tunnel. One system used a neural network to schedule flutter suppression control laws, another employed a neural network in a predictive control scheme, and the third employed a neural network in an inverse model control scheme. All three of these control schemes successfully suppressed flutter to or near the limits of the testing apparatus, and represent the first experimental applications of neural networks to flutter suppression. This paper will summarize the findings of this project.

Scott, Robert C.

2000-01-01

169

PERFORMANCE ANALYSIS OF MECHANICAL DRAFT COOLING TOWER  

SciTech Connect

Industrial processes use mechanical draft cooling towers (MDCT's) to dissipate waste heat by transferring heat from water to air via evaporative cooling, which causes air humidification. The Savannah River Site (SRS) has cross-flow and counter-current MDCT's consisting of four independent compartments called cells. Each cell has its own fan to help maximize heat transfer between ambient air and circulated water. The primary objective of the work is to simulate the cooling tower performance for the counter-current cooling tower and to conduct a parametric study under different fan speeds and ambient air conditions. The Savannah River National Laboratory (SRNL) developed a computational fluid dynamics (CFD) model and performed the benchmarking analysis against the integral measurement results to accomplish the objective. The model uses three-dimensional steady-state momentum, continuity equations, air-vapor species balance equation, and two-equation turbulence as the basic governing equations. It was assumed that vapor phase is always transported by the continuous air phase with no slip velocity. In this case, water droplet component was considered as discrete phase for the interfacial heat and mass transfer via Lagrangian approach. Thus, the air-vapor mixture model with discrete water droplet phase is used for the analysis. A series of parametric calculations was performed to investigate the impact of wind speeds and ambient conditions on the thermal performance of the cooling tower when fans were operating and when they were turned off. The model was also benchmarked against the literature data and the SRS integral test results for key parameters such as air temperature and humidity at the tower exit and water temperature for given ambient conditions. Detailed results will be published here.

Lee, S; Alfred Garrett, A; James02 Bollinger, J; Larry Koffman, L

2009-02-10

170

CO2, CO and CH4 measurements from the NOAA Earth System Research Laboratory's Tall Tower Greenhouse Gas Observing Network: instrumentation, uncertainty analysis and recommendations for future high-accuracy greenhouse gas monitoring efforts  

NASA Astrophysics Data System (ADS)

A robust in situ CO2 and CO analysis system has been developed and deployed at eight sites in the NOAA Earth System Research Laboratory's (ESRL) Tall Tower Greenhouse Gas Observing Network. The network uses very tall (> 300 m) television and radio transmitter towers that provide a convenient platform for mid-boundary layer trace gas sampling. Each analyzer has three sample inlets for profile sampling, and a complete vertical profile is obtained every 15 min. The instrument suite at one site has been augmented with a cavity ring-down spectrometer for measuring CO2 and CH4. The long-term stability of the systems in the field is typically better than 0.1 ppm for CO2, 6 ppb for CO, and 0.5 ppb for CH4, as determined from repeated standard gas measurements. The instrumentation is fully automated and includes sensors for measuring a variety of status parameters, such as temperatures, pressures and flow rates that are inputs for automated alerts and quality control algorithms. These algorithms provide detailed and time-dependent uncertainty estimates for all of the gases and could be adapted to other species or analysis systems. The design emphasizes use of off the shelf parts and modularity to facilitate network operations and ease of maintenance. The systems report high-quality data with > 93% uptime. Recurrent problems and limitations of the current system are discussed along with general recommendations for high accuracy trace-gas monitoring. The network is a key component of the North American Carbon Program and a useful model for future research-grade operational greenhouse gas monitoring efforts.

Andrews, A. E.; Kofler, J. D.; Trudeau, M. E.; Williams, J. C.; Neff, D. H.; Masarie, K. A.; Chao, D. Y.; Kitzis, D. R.; Novelli, P. C.; Zhao, C. L.; Dlugokencky, E. J.; Lang, P. M.; Crotwell, M. J.; Fischer, M. L.; Parker, M. J.; Lee, J. T.; Baumann, D. D.; Desai, A. R.; Stanier, C. O.; de Wekker, S. F. J.; Wolfe, D. E.; Munger, J. W.; Tans, P. P.

2013-02-01

171

Installation and initial operation of a 4100 watt wind turbine  

NASA Technical Reports Server (NTRS)

The results are presented of 211 days of operation of the 4.1 kilowatt wind turbine, which was the largest commercially available wind turbine. The wind turbine, electric controls and load bank, and the pivoted tower are described.

Tryon, H. B.; Richards, T.

1975-01-01

172

Development of large wind energy power generation system  

NASA Technical Reports Server (NTRS)

The background and development of an experimental 100 kW wind-energy generation system are described, and the results of current field tests are presented. The experimental wind turbine is a two-bladed down-wind horizontal axis propeller type with a 29.4 m diameter rotor and a tower 28 m in height. The plant was completed in March, 1983, and has been undergoing trouble-free tests since then. The present program calls for field tests during two years from fiscal 1983 to 1984. The development of technologies relating to the linkage and operation of wind-energy power generation system networks is planned along with the acquisition of basic data for the development of a large-scale wind energy power generation system.

1985-01-01

173

Combining tower mixing ratio and community model data to estimate regionalscale net ecosystem carbon exchange  

E-print Network

and intraannual variations similar to the tower NEE fluxes at the Rannells Prairie and Wind River Forest sites, Harvard University, Cambridge, Massachusetts, USA. 7 Department of Agronomy, Kansas State University, Manhattan, Kansas, USA. 8 Department of Biology, University of U

Ehleringer, Jim

174

WIND DATA REPORT WBZ Tower, Hull, MA  

E-print Network

) Golden Field Office 1617 Cole Blvd Golden, CO 80401 Division of Energy Resources (DOER) 100 Cambridge St........................................................................................................................ 4 SECTION 1 - Station Location....................................................................................................... 5 SECTION 2 - Instrumentation and Equipment

Massachusetts at Amherst, University of

175

Design and Construction of a Scaled Whirl Tower Facility  

Microsoft Academic Search

Experimental development of helicopter rotors requires centrifugal testing before entry into a wind tunnel or flight test campaign. This centrifugal testing is performed on test rigs called whirl towers. These facilities are very rare, in fact there were none available in Canada at the time of writing this thesis, but they are very valuable experimental research tools. This thesis describes

John Alexander Pickard

2010-01-01

176

Prediction of Aerodynamic Coefficients for Wind Tunnel Data using a Genetic Algorithm Optimized Neural Network  

NASA Technical Reports Server (NTRS)

A fast, reliable way of predicting aerodynamic coefficients is produced using a neural network optimized by a genetic algorithm. Basic aerodynamic coefficients (e.g. lift, drag, pitching moment) are modelled as functions of angle of attack and Mach number. The neural network is first trained on a relatively rich set of data from wind tunnel tests of numerical simulations to learn an overall model. Most of the aerodynamic parameters can be well-fitted using polynomial functions. A new set of data, which can be relatively sparse, is then supplied to the network to produce a new model consistent with the previous model and the new data. Because the new model interpolates realistically between the sparse test data points, it is suitable for use in piloted simulations. The genetic algorithm is used to choose a neural network architecture to give best results, avoiding over-and under-fitting of the test data.

Rajkumar, T.; Aragon, Cecilia; Bardina, Jorge; Britten, Roy

2002-01-01

177

Winds  

NSDL National Science Digital Library

In this problem-based learning (PBL) scenario, students prepare a presentation for investors showing how their fishing company has a significant advantage because it locates upwelling zones and fishing areas using TRMM (Tropical Rainfall Measuring Mission) and other satellite data. Prior to launching the PBL, students learn about wind: the topics of air pressure, coriolis effect, upwelling and the role of differential heating on the atmosphere are explored in classroom demonstrations. Materials required include a beaker, coffee grounds, drinking straw, balloon, flashlight, and turntable. The resource includes teacher background information, glossary, assessment rubric, and an appendix introducing problem-based learning.

178

Integration of offshore wind farms through high voltage direct current networks  

NASA Astrophysics Data System (ADS)

The integration of offshore wind farms through Multi Terminal DC (MTDC) networks into the GB network was investigated. The ability of Voltage Source Converter (VSC) High Voltage Direct Current (HVDC) to damp Subsynchronous Resonance (SSR) and ride through onshore AC faults was studied. Due to increased levels of wind generation in Scotland, substantial onshore and offshore reinforcements to the GB transmission network are proposed. Possible inland reinforcements include the use of series compensation through fixed capacitors. This potentially can lead to SSR. Offshore reinforcements are proposed by two HVDC links. In addition to its primary functions of bulk power transmission, a HVDC link can be used to provide damping against SSR, and this function has been modelled. Simulation studies have been carried out in PSCAD. In addition, a real-time hardware-in-the-loop HVDC test rig has been used to implement and validate the proposed damping scheme on an experimental platform. When faults occur within AC onshore networks, offshore MTDC networks are vulnerable to DC overvoltages, potentially damaging the DC plant and cables. Power reduction and power dissipation control systems were investigated to ride through onshore AC faults. These methods do not require dedicated fast communication systems. Simulations and laboratory experiments are carried out to evaluate the control systems, with the results from the two platforms compared..

Livermore, Luke

179

Tornado type wind turbines  

SciTech Connect

A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.

Hsu, Ch.-T.

1984-06-05

180

Networked Control System Wind Tunnel (NCSWT)-An evaluation tool for networked multi-agent systems  

E-print Network

-physical systems, such groups of unmanned aerial vehicles, are often monitored and controlled by networked control ...$10.00. ing wireless networks such as medical device networks or groups of unmanned vehicles. NCS research is an active area, investigating problems at the intersection of control systems, networking

Koutsoukos, Xenofon D.

181

Operational Wind Retrieval Within the Frame of the French Weather Radar Network  

NASA Astrophysics Data System (ADS)

The recent deployment of an innovative triple-PRT Doppler scheme within the French operational radar network, named ARAMIS, allows collecting reflectivity and radial velocity measurements simultaneously up to a range of 250 km with no ambiguity. This achievement brings new perspectives in terms of exploitation of operational radar measurements such as the long-anticipated capability to perform multiple-Doppler wind retrieval in a fully operational framework. Accordingly, and for the first time ever, a method allowing to consistently retrieve complete wind vector fields (u, v, w) in real-time from operational radar systems is being tested by the French national weather service since early 2007. This study proposes to describe the experimental setup relied upon to operationally retrieve multiple-Doppler winds in the frame of ARAMIS, as well as to investigate the potential of this new product for weather forecast applications. Using high resolution numerical wind forecasts in a variety of weather situations, we also show that these radar-derived wind fields compose unprecedented datasets to evaluate and further improve high-resolution numerical weather prediction systems being currently deployed by many national weather services.

Bousquet, O.; Tabary, P.; Parent-Du-Châtelet, J.; Périer, L.

2008-12-01

182

Model equations for the Eiffel Tower profile: historical perspective and new results  

NASA Astrophysics Data System (ADS)

Model equations for the shape of the Eiffel Tower are investigated. One model purported to be based on Eiffel's writing does not give a tower with the correct curvature. A second popular model not connected with Eiffel's writings provides a fair approximation to the tower's skyline profile of 29 contiguous panels. Reported here is a third model derived from Eiffel's concern about wind loads on the tower, as documented in his communication to the French Civil Engineering Society on 30 March 1885. The result is a nonlinear, integro-differential equation which is solved to yield an exponential tower profile. It is further verified that, as Eiffel wrote, "in reality the curve exterior of the tower reproduces, at a determined scale, the same curve of the moments produced by the wind". An analysis of the actual tower profile shows that it is composed of two piecewise continuous exponentials with different growth rates. This is explained by specific safety factors for wind loading that Eiffel & Company incorporated in the design of the free-standing tower. To cite this article: P. Weidman, I. Pinelis, C. R. Mecanique 332 (2004).

Weidman, Patrick; Pinelis, Iosif

2004-07-01

183

Conservation strategies for cooling towers  

SciTech Connect

This article compares the conventional construction with modern technology in order to upgrade a cooling tower to produce higher levels of colder water which will conserve energy with its utilization. The three major elements of the cooling tower are air handling, water distribution, and heat transfer surfaces. It is pointed out that while all cooling towers are purchased to function at 100% of capability in accordance with the required design conditions, in actual onstream employment, the level of operation often is lower, down to as much as 50%, because the present service needed is greater than the original requirements for which the tower was purchased; ''slippage,'' due to usage and perhaps deficient maintenance, has reduced the performance of the tower over years of operation; the installation could have been originally undersized due to the low-bidder syndrome; and new plant expansion needs additional water volume and possibly colder temperatures off the tower.

Burger, R.

1983-12-01

184

Improving Process Cooling Tower Eddiciency  

E-print Network

-Fifth Industrial Energy Technology Conference New Orleans, LA. May 21-24, 2013 2 Types of Cooling Towers Forced Draft Towers ESL-IE-13-05-08 Proceedings of the Thrity-Fifth Industrial Energy Technology Conference New Orleans, LA. May 21-24, 2013 3 Types... of Cooling Towers Induced draft Cross-flow ESL-IE-13-05-08 Proceedings of the Thrity-Fifth Industrial Energy Technology Conference New Orleans, LA. May 21-24, 2013 4 Types of Cooling Towers Induced Draft-Counter Flow Two-cell Single Cell Four Cell...

Turpish, W.

2013-01-01

185

Influence of Wind Turbulence on Yaw-control Gears in Wind Turbine  

Microsoft Academic Search

This paper describes an influence of wind turbulence on yaw-control gears of nacelle in a wind power station. This site is located in Tappi cape of Aomori prefecture where is characterized by a big wind turbulence due to the western strong wind and a steep slope of the cape. In this paper two adjacent wind towers are dealt with among

Kazuo Suzuki; Naoki Hoshino; Noboru Inomata; Hiroshi Kimura; Tamiya Fujiwara

2009-01-01

186

2. Southern Light Tower and Northern Light Tower, view north, ...  

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

2. Southern Light Tower and Northern Light Tower, view north, south sides - Kennebec River Light Station, South side of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

187

Dynamic responses and vibration control of the transmission tower-line system: a state-of-the-art review.  

PubMed

This paper presented an overview on the dynamic analysis and control of the transmission tower-line system in the past forty years. The challenges and future developing trends in the dynamic analysis and mitigation of the transmission tower-line system under dynamic excitations are also put forward. It also reviews the analytical models and approaches of the transmission tower, transmission lines, and transmission tower-line systems, respectively, which contain the theoretical model, finite element (FE) model and the equivalent model; shows the advances in wind responses of the transmission tower-line system, which contains the dynamic effects under common wind loading, tornado, downburst, and typhoon; and discusses the dynamic responses under earthquake and ice loads, respectively. The vibration control of the transmission tower-line system is also reviewed, which includes the magnetorheological dampers, friction dampers, tuned mass dampers, and pounding tuned mass dampers. PMID:25105161

Chen, Bo; Guo, Wei-hua; Li, Peng-yun; Xie, Wen-ping

2014-01-01

188

FLORIDA TOWER FOOTPRINT EXPERIMENTS  

SciTech Connect

The Florida Footprint experiments were a series of field programs in which perfluorocarbon tracers were released in different configurations centered on a flux tower to generate a data set that can be used to test transport and dispersion models. These models are used to determine the sources of the CO{sub 2} that cause the fluxes measured at eddy covariance towers. Experiments were conducted in a managed slash pine forest, 10 km northeast of Gainesville, Florida, in 2002, 2004, and 2006 and in atmospheric conditions that ranged from well mixed, to very stable, including the transition period between convective conditions at midday to stable conditions after sun set. There were a total of 15 experiments. The characteristics of the PFTs, details of sampling and analysis methods, quality control measures, and analytical statistics including confidence limits are presented. Details of the field programs including tracer release rates, tracer source configurations, and configuration of the samplers are discussed. The result of this experiment is a high quality, well documented tracer and meteorological data set that can be used to improve and validate canopy dispersion models.

WATSON,T.B.; DIETZ, R.N.; WILKE, R.; HENDREY, G.; LEWIN, K.; NAGY, J.; LECLERC, M.

2007-01-01

189

76 FR 490 - Marking Meteorological Evaluation Towers  

Federal Register 2010, 2011, 2012, 2013, 2014

...the particular structure would be hazardous to aviation. These towers are often installed...determine whether these structures are obstructions...acknowledge that these towers under certain conditions...tanks and similar structures, and towers that have...

2011-01-05

190

Runway Transgressions at Non-Towered and  

E-print Network

View California 94043 NASA ASRS (Pub. 61) #12;ASRS Non-Towered Airports Runway Transgressions Study-Towered and Tower-Closed Airports July 14, 2003 Aviation Safety Reporting System 625 Ellis St. Suite 305 Mountain

191

Short-term load and wind power forecasting using neural network-based prediction intervals.  

PubMed

Electrical power systems are evolving from today's centralized bulk systems to more decentralized systems. Penetrations of renewable energies, such as wind and solar power, significantly increase the level of uncertainty in power systems. Accurate load forecasting becomes more complex, yet more important for management of power systems. Traditional methods for generating point forecasts of load demands cannot properly handle uncertainties in system operations. To quantify potential uncertainties associated with forecasts, this paper implements a neural network (NN)-based method for the construction of prediction intervals (PIs). A newly introduced method, called lower upper bound estimation (LUBE), is applied and extended to develop PIs using NN models. A new problem formulation is proposed, which translates the primary multiobjective problem into a constrained single-objective problem. Compared with the cost function, this new formulation is closer to the primary problem and has fewer parameters. Particle swarm optimization (PSO) integrated with the mutation operator is used to solve the problem. Electrical demands from Singapore and New South Wales (Australia), as well as wind power generation from Capital Wind Farm, are used to validate the PSO-based LUBE method. Comparative results show that the proposed method can construct higher quality PIs for load and wind power generation forecasts in a short time. PMID:24807030

Quan, Hao; Srinivasan, Dipti; Khosravi, Abbas

2014-02-01

192

Estimating Planetary Boundary Layer Heights from NOAA Profiler Network Wind Profiler Data  

NASA Technical Reports Server (NTRS)

An algorithm was developed to estimate planetary boundary layer (PBL) heights from hourly archived wind profiler data from the NOAA Profiler Network (NPN) sites located throughout the central United States. Unlike previous studies, the present algorithm has been applied to a long record of publicly available wind profiler signal backscatter data. Under clear conditions, summertime averaged hourly time series of PBL heights compare well with Richardson-number based estimates at the few NPN stations with hourly temperature measurements. Comparisons with clear sky reanalysis based estimates show that the wind profiler PBL heights are lower by approximately 250-500 m. The geographical distribution of daily maximum PBL heights corresponds well with the expected distribution based on patterns of surface temperature and soil moisture. Wind profiler PBL heights were also estimated under mostly cloudy conditions, and are generally higher than both the Richardson number based and reanalysis PBL heights, resulting in a smaller clear-cloudy condition difference. The algorithm presented here was shown to provide a reliable summertime climatology of daytime hourly PBL heights throughout the central United States.

Molod, Andrea M.; Salmun, H.; Dempsey, M

2015-01-01

193

Weird Geology: The Devil's Tower  

NSDL National Science Digital Library

This page features a brief introduction to the several theories about the geological processes that formed Devil's Tower, which rises 1,267 feet above the nearby Belle Fourche River and is still considered a sacred place by some Native American Tribes. Information on climbing the tower as well as images and a cross section are provided.

Krystek, Lee; Mystery, The M.

194

Natural-draft Cooling Tower  

USGS Multimedia Gallery

Natural-draft cooling towers and one of two intake screens and associated pumps for the Tennessee Valley Authority, Sequoyah Nuclear Power Plant, Tennessee. Natural-draft tower airflow is drawn through the packing or fill (distributed at the base) by means of the small density difference between the...

195

Observing wind, aerosol particles, cloud and precipitation: Finland's new ground-based remote-sensing network  

NASA Astrophysics Data System (ADS)

The Finnish Meteorological Institute, in collaboration with the University of Helsinki, has established a new ground-based remote-sensing network in Finland. The network consists of five topographically, ecologically and climatically different sites distributed from southern to northern Finland. The main goal of the network is to monitor air pollution and boundary layer properties in near real time, with a Doppler lidar and ceilometer at each site. In addition to these operational tasks, two sites are members of the Aerosols, Clouds, and Trace gases Research InfraStructure Network (ACTRIS); a Ka-band Doppler cloud radar at Sodankylä will provide cloud retrievals within CloudNet, and a multi-wavelength Raman lidar, POLLYXT (POrtabLe Lidar sYstem eXTended), in Kuopio provides optical and microphysical aerosol properties through EARLINET (European Aerosol Research Lidar Network to Establish an Aerosol Climatology). Three C-band weather radars are located in the Helsinki metropolitan area and are deployed for operational and research applications. We carried out two inter-comparison campaigns to investigate the Doppler lidar performance. The aims of the campaigns were to compare the backscatter coefficient and retrieved wind profiles, and to optimise the lidar sensitivity through adjusting the telescope focus and data-integration time to ensure enough signals in low-aerosol-content environments. The wind profiles showed good agreement between different lidars. However, due to inaccurate telescope focus setting and varying receiver sensitivity, backscatter coefficient profiles showed disagreement between the lidars. Harsh Finnish winters could pose problems, but, due to the built-in heating systems, low ambient temperatures had no, or only a minor, impact on the lidar operation: including scanning-head motion. However, accumulation of snow and ice on the lens has been observed, which can lead to formation of a water/ice layer thus attenuating the signal inconsistently. Thus, care must be taken to ensure continuous snow removal.

Hirsikko, A.; O'Connor, E. J.; Komppula, M.; Korhonen, K.; Pfüller, A.; Giannakaki, E.; Wood, C. R.; Bauer-Pfundstein, M.; Poikonen, A.; Karppinen, T.; Lonka, H.; Kurri, M.; Heinonen, J.; Moisseev, D.; Asmi, E.; Aaltonen, V.; Nordbo, A.; Rodriguez, E.; Lihavainen, H.; Laaksonen, A.; Lehtinen, K. E. J.; Laurila, T.; Petäjä, T.; Kulmala, M.; Viisanen, Y.

2013-08-01

196

A review on wind driven ventilation techniques  

Microsoft Academic Search

Natural ventilation has gained prominence in recent times as a bespoke method of ventilating buildings. The two fundamental principles of natural ventilation are stack effect and wind driven ventilation. This paper reviews miscellaneous wind driven ventilation designs with respect to traditional means such as wind towers and more modern techniques including turbine ventilators and wind catchers. A distinction is made

Naghman Khan; Yuehong Su; Saffa B. Riffat

2008-01-01

197

The Tower of London  

NSDL National Science Digital Library

As one of the most famous complexes of historic structures in the world, it stands to reason that the Tower of London would have a plethora of websites dedicated to exploring its development and rather crucial role in English history. Begun by William the Conquerer, the castle has been improved and added upon numerous times over the past 900 years, and now includes dozens of smaller structures within its walls. Developed by staff members at Knight International, this site is a real treat for those seeking to learn more about this historic site, or those who might be planning a visit in the future. The site contains approximately a dozen different areas of interest, ranging from a fine virtual tour of the grounds, a section devoted to the omnipresent ravens and, of course, a copious amount of materials on the Crown Jewels.

198

SkyTower Telecommunications  

NSDL National Science Digital Library

Helios is the name of an unmanned, solar powered aircraft that broke many records and made history on its first successful flight last summer. With more flights scheduled for this summer, there is growing interest in the potential applications of so-called "atmospheric satellites" like Helios. This Web site, operated by the company that developed the prototype, has lots of information about the aircraft, its specifications, and, most importantly, its possible uses. The main focus is on telecommunications; because this kind of aircraft could remain at high altitudes for long periods of time, it could be used as an extremely tall tower that relays signals to and from ground stations. A video clip demonstrating this technology is also provided on the site.

199

Grid integration of wind energy: A case study on a typical sub-transmission network in Namibia  

Microsoft Academic Search

This paper presents a case study on the transient performance of a typical sub-transmission network in Namibia in relation to grid integration of wind energy. The authors focus on the relative impact of two wind generator technologies, viz. direct-driven synchronous generator (DDSG) and doubly-fed induction generator (DFIG). Important aspects investigated are the impacts of penetration levels (generation capacity) of the

A. I. Elombo; S. P. Chowdhury; H. J. Vermeulen

2010-01-01

200

Direct adaptive control of wind energy conversion systems using Gaussian networks.  

PubMed

Grid connected wind energy conversion systems (WECS) present interesting control demands, due to the intrinsic nonlinear characteristics of windmills and electric generators. In this paper a direct adaptive control strategy for WECS control is proposed. It is based on the combination of two control actions: a radial basis zfunction network-based adaptive controller, which drives the tracking error to zero with user specified dynamics, and a supervisory controller, based on crude bounds of the system's nonlinearities. The supervisory controller fires when the finite neural-network approximation properties cannot be guaranteed. The form of the supervisor control and the adaptation law for the neural controller are derived from a Lyapunov analysis of stability. The results are applied to a typical turbine/generator pair, showing the feasibility of the proposed solution. PMID:18252585

Mayosky, M A; Cancelo, I E

1999-01-01

201

Paper accepted for presentation at 2003 IEEE Bologna PowerTech Conference, June 23-26, Bologna, Italy Wind Power Forecasting using Fuzzy Neural Networks  

E-print Network

, Italy Wind Power Forecasting using Fuzzy Neural Networks Enhanced with On-line Prediction Risk) as input, to predict the power production of wind park8 48 hours ahead. The prediction system integrates of the numerical weather predictions. Index Term-Wind power, short-term forecasting, numerical weather predictions

Paris-Sud XI, Université de

202

Prediction of the Dst index from solar wind parameters by a neural network method  

NASA Astrophysics Data System (ADS)

Using the Elman-type neural network technique, operational models are constructed that predict the Dst index two hours in advance. The input data consist of real-time solar wind velocity, density, and magnetic field data obtained by the Advanced Composition Explorer (ACE) spacecraft since May 1998 (http://www2.crl.go.jp/uk/uk223/service/nnw/index.html). During the period from February to October 1998, eleven storms occurred with minimum Dst values below -80 nT. For ten of these storms the differences between the predicted minimum Dst and the minimum Dst calculated from ground-based magnetometer data were less than 23%. For the remaining one storm (beginning on 19 October 1998) the difference was 48%. The discrepancy is likely to stem from a imperfect correlation between the solar wind parameters near ACE and those near the earth. While the IMF Bz remains to be the most important parameter, other parameters do have their effects. For instance, Dst appears to be enhanced when the azimuthal direction of IMF is toward the sun. A trapezoid-shaped increase in the solar wind density enhances the main phase Dst by almost 10% compared with the case of no density increase. Velocity effects appear to be stronger than the density effects. Our operational models have, in principle, no limitations in applicability with respect to storm intensity.

Watanabe, S.; Sagawa, E.; Ohtaka, K.; Shimazu, H.

2002-12-01

203

Relative importance of parameters affecting wind speed prediction using artificial neural networks  

NASA Astrophysics Data System (ADS)

In traditional artificial neural networks (ANN) models, the relative importance of the individual meteorological input variables is often overlooked. A case study is presented in this paper to model monthly wind speed values using meteorological data (air pressure, air temperature, relative humidity, and precipitation), where the study also includes an estimate of the relative importance of these variables. Recorded monthly mean data are available at a gauging site in Tabriz, Azerbaijan, Iran, for the period from 2000 to 2005, gauged in the city at the outskirt of alluvial funneling mountains with an established microclimatic conditions and a diurnal wind regime. This provides a sufficiently severe test for the ANN model with a good predictive capability of 1 year of lead time but without any direct approach to refer the predicted results to local microclimatic conditions. A method is used in this paper to calculate the relative importance of each meteorological input parameters affecting wind speed, showing that air pressure and precipitation are the most and least influential parameters with approximate values of 40 and 10 %, respectively. This gained knowledge corresponds to the local knowledge of the microclimatic and geomorphologic conditions surrounding Tabriz.

Ghorbani, M. A.; Khatibi, R.; Hosseini, B.; Bilgili, M.

2013-10-01

204

CO2, CO, and CH4 measurements from tall towers in the NOAA Earth System Research Laboratory's Global Greenhouse Gas Reference Network: instrumentation, uncertainty analysis, and recommendations for future high-accuracy greenhouse gas monitoring efforts  

NASA Astrophysics Data System (ADS)

A reliable and precise in situ CO2 and CO analysis system has been developed and deployed at eight sites in the NOAA Earth System Research Laboratory's (ESRL) Global Greenhouse Gas Reference Network. The network uses very tall (> 300 m) television and radio transmitter towers that provide a convenient platform for mid-boundary-layer trace-gas sampling. Each analyzer has three sample inlets for profile sampling, and a complete vertical profile is obtained every 15 min. The instrument suite at one site has been augmented with a cavity ring-down spectrometer for measuring CO2 and CH4. The long-term stability of the systems in the field is typically better than 0.1 ppm for CO2, 6 ppb for CO, and 0.5 ppb for CH4, as determined from repeated standard gas measurements. The instrumentation is fully automated and includes sensors for measuring a variety of status parameters, such as temperatures, pressures, and flow rates, that are inputs for automated alerts and quality control algorithms. Detailed and time-dependent uncertainty estimates have been constructed for all of the gases, and the uncertainty framework could be readily adapted to other species or analysis systems. The design emphasizes use of off-the-shelf parts and modularity to facilitate network operations and ease of maintenance. The systems report high-quality data with > 93% uptime. Recurrent problems and limitations of the current system are discussed along with general recommendations for high-accuracy trace-gas monitoring. The network is a key component of the North American Carbon Program and a useful model for future research-grade operational greenhouse gas monitoring efforts.

Andrews, A. E.; Kofler, J. D.; Trudeau, M. E.; Williams, J. C.; Neff, D. H.; Masarie, K. A.; Chao, D. Y.; Kitzis, D. R.; Novelli, P. C.; Zhao, C. L.; Dlugokencky, E. J.; Lang, P. M.; Crotwell, M. J.; Fischer, M. L.; Parker, M. J.; Lee, J. T.; Baumann, D. D.; Desai, A. R.; Stanier, C. O.; De Wekker, S. F. J.; Wolfe, D. E.; Munger, J. W.; Tans, P. P.

2014-02-01

205

PBF Cooling Tower. Hot deck of Cooling Tower with fan ...  

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

PBF Cooling Tower. Hot deck of Cooling Tower with fan motors in place. Fan's propeller blades (not in view) rotate within lower portion of vents. Inlet pipe is a left of view. Contractor's construction buildings in view to right. Photographer: Larry Page. Date: June 30, 1969. INEEL negative no. 69-3781 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

206

WindFloat: A floating foundation for offshore wind turbines  

Microsoft Academic Search

This manuscript summarizes the feasibility study conducted for the WindFloat technology. The WindFloat is a three-legged floating foundation for multimegawatt offshore wind turbines. It is designed to accommodate a wind turbine, 5 MW or larger, on one of the columns of the hull with minimal modifications to the nacelle and rotor. Potential redesign of the tower and of the turbine

Dominique Roddier; Christian Cermelli; Alexia Aubault; Alla Weinstein

2010-01-01

207

World Federation of Great Towers  

NSDL National Science Digital Library

The World Federation of Great Towers (WFGT) "is an association of international monuments which join together to foster global awareness and develop international opportunities for promotion." The organization provides this eye-catching site that contains detailed information and pictures of over twenty towers from around the world. After giving a brief background summary of each tower's location and notable characteristics, specifications and technical data are provided to give an impression of the scale of the structures and the engineering skill that was needed in their construction. Although only the buildings that are members of the WFGT are featured online, the collection does a good job of capturing some of the most impressive towers in existence.

208

Hoover Dam Intake Towers Panorama  

USGS Multimedia Gallery

Hoover Dam impounds Lake Mead and provides drinking water and hydroelectric power to the surrounding area. It was constructed between 1931 and 1936. The Intake Towers are where water enters to generate electricity....

209

Ozonation of cooling tower waters  

NASA Technical Reports Server (NTRS)

Continuous ozone injection into water circulating between a cooling tower and heat exchanger with heavy scale deposits inhibits formation of further deposits, promotes flaking of existing deposits, inhibits chemical corrosion and controls algae and bacteria.

Humphrey, M. F.; French, K. R.; Howe, R. D. (inventors)

1979-01-01

210

Performance of Tornado Wind Energy Conversion Systems  

SciTech Connect

The flow characteristics and power production capabilities of the Tornado Wind Energy Conversion System (TWECS) are examined. Experimental results indicate that the confined vortex in the tower of TWECS rotates approximately as a solid body and only supplements total power production, most of which comes from the tower acting as a bluff body. Wrapped tower experiments were performed by fitting a plastic shroud 360 deg around the tower from the top of the bottom inlet to the tower exit level which transformed the TWECS into a hollow, raised cylinder. Coefficient of power is compared for louvered towers vs. wrapped tower. The fact that the wrapped tower performs as well as the louvered tower suggests that it is the pressure difference between the bottom inlet region and the region above the tower (where the pressure of the ambient flow will be somewhat reduced owing to its acceleration over the bluff body of the tower) which determines the vertical force on the fluid within the tower.

Volk, T.

1982-09-01

211

Observational constraints on U.S. emissions of climate-active and ozone-depleting trace gases from a tall-tower and aircraft sampling network  

NASA Astrophysics Data System (ADS)

Air samples have been regularly collected at a number of tall tower sites and from aircraft profiling locations across the U.S. and Canada during the past 4 to 5 years. Measurements of approximately 50 trace gases in these samples provide a rich dataset of chemical markers related to urban, industrial, oceanic, biomass burning, fossil-fuel burning, atmospheric mixing, photosynthesis, and soil influences. Anthropogenic emission signals are readily apparent in the halocarbon and hydrocarbon data, upon which this talk will focus. Measured correlations between different halocarbons (especially hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs)) show variations as a function of season that are qualitatively consistent with the expected regional and seasonal patterns of use and emission of these industrially-produced chemicals. In some instances, annual mean correlation slopes between different trace gases are well described by the U.S. EPA Greenhouse Gas Emission Inventories, but for others, large differences are observed. Furthermore, interannual changes in correlation slopes are expected for gases that are being phased out (i.e., HCFCs) compared to those for which emissions may be increasing (i.e., HFCs) in the US. This presentation will focus on the regional, seasonal, and interannual variations in trace gas emissions implied from a straightforward analysis of this extensive measurement record.

Montzka, S. A.; Miller, B. R.; Siso, C.; Sweeney, C.; Andrews, A. E.; Karion, A.; Neff, D.; Fischer, M. L.; Higgs, J.

2010-12-01

212

Detail of antenna tower structure, looking northnorthwest OvertheHorizon Backscatter ...  

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

Detail of antenna tower structure, looking north-northwest - Over-the-Horizon Backscatter Radar Network, Tulelake Radar Site Receive Sector Five Antenna Array, Unnamed Road West of Double Head Road, Tulelake, Siskiyou County, CA

213

A Dynamic Wind Turbine Simulator of the Wind Turbine Generator System  

Microsoft Academic Search

To study dynamic performances of wind turbine generator system (WTGS), and to determine the control structures in laboratory. The dynamic torque generated by wind turbine (WT) must be simulated. In there paper, a dynamic wind turbine emulator (WTE) is designed, which consider wind shear and tower shadow effect, and a dynamic torque compensation scheme is also developed to compensate the

Lei Lu; Zhen Xie; Xing Zhang; Shuying Yang; Renxian Cao

2012-01-01

214

Effect of Wind Speed on Aerosol Optical Depth over Remote Oceans, Based on Data from the Maritime Aerosol Network  

NASA Technical Reports Server (NTRS)

The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. The MAN archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we investigate correlations between ship-borne aerosol optical depth (AOD) and near-surface wind speed, either measured (onboard or from satellite) or modeled (NCEP). According to our analysis, wind speed influences columnar aerosol optical depth, although the slope of the linear regression between AOD and wind speed is not steep (approx. 0.004 - 0.005), even for strong winds over 10m/s. The relationships show significant scatter (correlation coefficients typically in the range 0.3 - 0.5); the majority of this scatter can be explained by the uncertainty on the input data. The various wind speed sources considered yield similar patterns. Results are in good agreement with the majority of previously published relationships between surface wind speed and ship-based or satellite-based AOD measurements. The basic relationships are similar for all the wind speed sources considered; however, the gradient of the relationship varies by around a factor of two depending on the wind data used

Smirnov, A.; Sayer, A. M.; Holben, B. N.; Hsu, N. C.; Sakerin, S. M.; Macke, A.; Nelson, N. B.; Courcoux, Y.; Smyth, T. J.; Croot, P.; Quinn, P. K.; Sciare, J.; Gulev, S. K.; Piketh, S.; Losno, R.; Kinne, S.; Radionov, V. F.

2012-01-01

215

A COOLING SYSTEM FOR BUIDINGS USING WIND ENERGY  

E-print Network

A COOLING SYSTEM FOR BUIDINGS USING WIND ENERGY Hamid Daiyan Islamic Azad University - Semnan in dray land, and only uses wind energy for conditioning. It technologies date back over 1000 years. Wind system, Wind energy, Temperature Fig.1 Wind tower of Doulat-Abad garden of Yazd with it's altitude is 33

216

Tower Temperature and Humidity Sensors (TWR) Handbook  

SciTech Connect

Three tall towers are installed at the Atmospheric Radiation Measurement (ARM) Climate Research Facility: a 60-meter triangular tower at the Southern Great Plains (SGP) Central Facility (CF), a 21-meter walkup scaffolding tower at the SGP Okmulgee forest site (E21), and a 40-meter triangular tower at the North Slope of Alaska (NSA) Barrow site. The towers are used for meteorological, radiological, and other measurements.

Cook, DR

2010-02-01

217

National-Scale Wind Resource Assessment for Power Generation (Presentation)  

SciTech Connect

This presentation describes the current standards for conducting a national-scale wind resource assessment for power generation, along with the risk/benefit considerations to be considered when beginning a wind resource assessment. The presentation describes changes in turbine technology and viable wind deployment due to more modern turbine technology and taller towers and shows how the Philippines national wind resource assessment evolved over time to reflect changes that arise from updated technologies and taller towers.

Baring-Gould, E. I.

2013-08-01

218

Observing wind, aerosol particles, cloud and precipitation: Finland's new ground-based remote-sensing network  

NASA Astrophysics Data System (ADS)

The Finnish Meteorological Institute, in collaboration with the University of Helsinki, has established a new ground-based remote-sensing network in Finland. The network consists of five topographically, ecologically and climatically different sites distributed from southern to northern Finland. The main goal of the network is to monitor air pollution and boundary layer properties in near real time, with a Doppler lidar and ceilometer at each site. In addition to these operational tasks, two sites are members of the Aerosols, Clouds and Trace gases Research InfraStructure Network (ACTRIS); a Ka band cloud radar at Sodankylä will provide cloud retrievals within CloudNet, and a multi-wavelength Raman lidar, PollyXT (POrtabLe Lidar sYstem eXTended), in Kuopio provides optical and microphysical aerosol properties through EARLINET (the European Aerosol Research Lidar Network). Three C-band weather radars are located in the Helsinki metropolitan area and are deployed for operational and research applications. We performed two inter-comparison campaigns to investigate the Doppler lidar performance, compare the backscatter signal and wind profiles, and to optimize the lidar sensitivity through adjusting the telescope focus length and data-integration time to ensure sufficient signal-to-noise ratio (SNR) in low-aerosol-content environments. In terms of statistical characterization, the wind-profile comparison showed good agreement between different lidars. Initially, there was a discrepancy in the SNR and attenuated backscatter coefficient profiles which arose from an incorrectly reported telescope focus setting from one instrument, together with the need to calibrate. After diagnosing the true telescope focus length, calculating a new attenuated backscatter coefficient profile with the new telescope function and taking into account calibration, the resulting attenuated backscatter profiles all showed good agreement with each other. It was thought that harsh Finnish winters could pose problems, but, due to the built-in heating systems, low ambient temperatures had no, or only a minor, impact on the lidar operation - including scanning-head motion. However, accumulation of snow and ice on the lens has been observed, which can lead to the formation of a water/ice layer thus attenuating the signal inconsistently. Thus, care must be taken to ensure continuous snow removal.

Hirsikko, A.; O'Connor, E. J.; Komppula, M.; Korhonen, K.; Pfüller, A.; Giannakaki, E.; Wood, C. R.; Bauer-Pfundstein, M.; Poikonen, A.; Karppinen, T.; Lonka, H.; Kurri, M.; Heinonen, J.; Moisseev, D.; Asmi, E.; Aaltonen, V.; Nordbo, A.; Rodriguez, E.; Lihavainen, H.; Laaksonen, A.; Lehtinen, K. E. J.; Laurila, T.; Petäjä, T.; Kulmala, M.; Viisanen, Y.

2014-05-01

219

Monitoring of wind pressure distribution at a supertall structure above maximum gradient wind level (presentation video)  

NASA Astrophysics Data System (ADS)

While the field measurement of wind speed at buildings and towers has been made by numerous investigators, the direct measurement of wind pressure at high-rise structures was seldom reported. Up to now, the information regarding wind pressure distribution above the maximum gradient wind level (it is 450 m stipulated in the Chinese code) has never been experimentally obtained. This paper presents a field monitoring investigation on the measurement of wind pressure and its distribution at the Canton Tower of 600 m high above the maximum gradient wind level during the typhoon Kaitak.

Ni, Y. Q.; Wang, Y. W.; Song, S. D.

2014-04-01

220

Development of solar tower observatories  

NASA Astrophysics Data System (ADS)

Because the horizontal solar telescope, the Snow Telescope in Yerkes Observatory, was affected by air-currents from the warmed-up soil, George Ellery Hale had the idea of a tower telescope. In 1904, the 60-foot tower in Mt. Wilson was ready, in 1908 the 150-foot tower was built with the help of the Carnegie foundation. After World War I, Germany made heavy efforts to regain its former strong position in the field of science. Already in December 1919 - after the spectacular result of the English eclipse expedition in October 1919 - Erwin Finlay-Freundlich started a successful fund raising (“Einstein-Stiftungrdquo;) among German industrialists. The company Zeiss in Jena was responsible for the instrumentation of the 20-m solar tower, built in 1920-22. The optical design of the Einstein Tower in respect to light intensity surpassed even the Mt. Wilson solar observatory. Also abroad solar tower observatories were built in the 1920s: Utrecht,The Netherlands (1922), Canberra, Australia (1924), Arcetri, Italy (1926), Pasadena, California (1926) and Tokyo, Japan (1928). In the thirties, solar physics became important because of the solar maximum in 1938 and the new observational possibilities created by Bernard Lyot. At the end of the 1930s, Karl-Otto Kiepenheuer proposed to establish a solar tower observatory on Wendelstein in order to improve the predictions of radio interference by observing sunspots. By stressing the importance of the solar research for war efforts, Otto Heckmann of Göttingen observatory finally succeeded in winning the “Reichsluftfahrtministerium” to finance several solar observatories, like Wendelstein, Hainberg/Göttingen, Kanzelhöhe/Villach, and Schauinsland/Freiburg. Solar astronomy profited by the foundation of the new observatories - four of them existed still after the war. Abroad only the solar observatories of Oxford (1935) and the 50 foot tower of the McMath-Hulbert Observatory, University of Michigan (1936) should be mentioned. Only a short outlook will be given to the modern solar tower telescopes like the McMath-Pierce Telescope (1960) and vacuum telescope (1973) at Kitt Peak, Arizona, the Richard B. Dunn Solar Telescope (1969), Sacramento Peak, New Mexico, and the Vacuum Tower Telescope of the “Observatorio del Teide”, Izaña, Teneriffa (1987).

Wolfschmidt, Gudrun

221

Comparative analysis of neural network and regression based condition monitoring approaches for wind turbine fault detection  

NASA Astrophysics Data System (ADS)

This paper presents the research results of a comparison of three different model based approaches for wind turbine fault detection in online SCADA data, by applying developed models to five real measured faults and anomalies. The regression based model as the simplest approach to build a normal behavior model is compared to two artificial neural network based approaches, which are a full signal reconstruction and an autoregressive normal behavior model. Based on a real time series containing two generator bearing damages the capabilities of identifying the incipient fault prior to the actual failure are investigated. The period after the first bearing damage is used to develop the three normal behavior models. The developed or trained models are used to investigate how the second damage manifests in the prediction error. Furthermore the full signal reconstruction and the autoregressive approach are applied to further real time series containing gearbox bearing damages and stator temperature anomalies. The comparison revealed all three models being capable of detecting incipient faults. However, they differ in the effort required for model development and the remaining operational time after first indication of damage. The general nonlinear neural network approaches outperform the regression model. The remaining seasonality in the regression model prediction error makes it difficult to detect abnormality and leads to increased alarm levels and thus a shorter remaining operational period. For the bearing damages and the stator anomalies under investigation the full signal reconstruction neural network gave the best fault visibility and thus led to the highest confidence level.

Schlechtingen, Meik; Ferreira Santos, Ilmar

2011-07-01

222

Wind Velocity and Convergence Measurements at the Boulder Atmospheric Observatory Using Path-Averaged Optical Wind Sensors  

Microsoft Academic Search

In a cooperative field study of the planetary boundary layer, three optical wind sensors were placed around a 300 m meteorological tower in a 450 m equilateral triangle 3-4 m above the terrain. It was found that the convergence measured by the three-sensor system correlates well with in situ measurements of vertical wind by anemometers located on the tower at

Mu-King Tsay; Ting-I. Wang; R. S. Lawrence; G. R. Ochs; R. B. Fritz

1980-01-01

223

Deployable tensegrity towers  

NASA Astrophysics Data System (ADS)

The design of a complete tensegrity system involves the analysis of static equilibria, the mechanical properties of the configuration, the deployment of the structure, and the regulation and dynamics of the system. This dissertation will explore these steps for two different types of structures. The first structure is the traditional Snelson Tower, where struts are disjointed, and is referred to as a Class 1 tensegrity. The second structure of interest is referred to as a Class 2 structure, where two struts come in contact at a joint. The first part of the thesis involves the dynamics of these tensegrity structures. Two complete nonlinear formulations for the dynamics of tensegrity systems are derived. In addition, a general formulation for the statics for an arbitrary tensegrity structure resulted from one of the dynamic formulations and is presented with symmetric and nonsymmetric tensegrity configurations. The second part of the thesis involves statics. The analysis of static equilibria and the implementation of this analysis into an open loop control law that will deploy the tensegrity structures along an equilibrium manifold are derived. The analysis of small stable tensegrity units allow for a modular design, where a collection of these units can be assembled into a larger structure that obeys the same control laws for deployment concepts. In addition, a loaded structure is analyzed to determine the optimal number of units required to obtain a minimal mass configuration. The third part of the thesis involves laboratory hardware that demonstrates the practical use of the methodology presented. A Class 2 symmetric structure is constructed, deployed, and stowed using the analysis from part two. In addition, the static equilibria of a Class 1 structure is computed to obtain nonsymmetric reconfigurations. The final part of the thesis involves the attenuation of white noise disturbances acting on nodes of both structures. The structures are simulated using linear quadratic gausian regulators (LQG) and a practical actuator selection scheme is proposed for the structures.

Pinaud, Jean-Paul

224

Integrated control of wind farms, FACTS devices and the power network using neural networks and adaptive critic designs  

NASA Astrophysics Data System (ADS)

Worldwide concern about the environmental problems and a possible energy crisis has led to increasing interest in clean and renewable energy generation. Among various renewable energy sources, wind power is the most rapidly growing one. Therefore, how to provide efficient, reliable, and high-performance wind power generation and distribution has become an important and practical issue in the power industry. In addition, because of the new constraints placed by the environmental and economical factors, the trend of power system planning and operation is toward maximum utilization of the existing infrastructure with tight system operating and stability margins. This trend, together with the increased penetration of renewable energy sources, will bring new challenges to power system operation, control, stability and reliability which require innovative solutions. Flexible ac transmission system (FACTS) devices, through their fast, flexible, and effective control capability, provide one possible solution to these challenges. To fully utilize the capability of individual power system components, e.g., wind turbine generators (WTGs) and FACTS devices, their control systems must be suitably designed with high reliability. Moreover, in order to optimize local as well as system-wide performance and stability of the power system, real-time local and wide-area coordinated control is becoming an important issue. Power systems containing conventional synchronous generators, WTGs, and FACTS devices are large-scale, nonlinear, nonstationary, stochastic and complex systems distributed over large geographic areas. Traditional mathematical tools and system control techniques have limitations to control such complex systems to achieve an optimal performance. Intelligent and bio-inspired techniques, such as swarm intelligence, neural networks, and adaptive critic designs, are emerging as promising alternative technologies for power system control and performance optimization. This work focuses on the development of advanced optimization and intelligent control algorithms to improve the stability, reliability and dynamic performance of WTGs, FACTS devices, and the associated power networks. The proposed optimization and control algorithms are validated by simulation studies in PSCAD/EMTDC, experimental studies, or real-time implementations using Real Time Digital Simulation (RTDS) and TMS320C6701 Digital Signal Processor (DSP) Platform. Results show that they significantly improve electrical energy security, reliability and sustainability.

Qiao, Wei

225

Wind Turbine With Concentric Ducts  

NASA Technical Reports Server (NTRS)

Wind Turbine device is relatively compact and efficient. Converging inner and outer ducts increase pressure difference across blades of wind turbine. Turbine shaft drives alternator housed inside exit cone. Suitable for installation on such existing structures as water towers, barns, houses, and commercial buildings.

Muhonen, A. J.

1983-01-01

226

Assessing offshore wind resources: An accessible methodology  

Microsoft Academic Search

This paper describes a method for assessing the electric production and value of wind resources, specifically for the offshore environment. Three steps constitute our method. First, we map the available area, delimiting bathymetric areas based on turbine tower technology, then assess competing uses of the ocean to establish exclusion zones. From exclusion zones, bathymetry, and turbine tower water depth limitations,

Amardeep Dhanju; Phillip Whitaker; Willett Kempton

2008-01-01

227

Assessing offshore wind resources: An accessible methodology  

Microsoft Academic Search

This paper describes a method for assessing the electric production and value of wind resources, specifically for the offshore environment. Three steps constitute our method. First, we map the available area, delimiting bathymetric areas based on turbine tower technology, then assess competing uses of the ocean to establish exclusion zones. From exclusion zones, bathymetry, and turbine tower water depth limitations,

Amardeep Dhanju; Phillip Whitaker; Willett Kempton

2007-01-01

228

Aeroelastic analysis of wind energy conversion systems  

NASA Technical Reports Server (NTRS)

An aeroelastic investigation of horizontal axis wind turbines is described. The study is divided into two simpler areas; (1) the aeroelastic stability of a single blade on a rigid tower; and (2) the mechanical vibrations of the rotor system on a flexible tower. Some resulting instabilities and forced vibration behavior are described.

Dugundji, J.

1978-01-01

229

The use of real-time off-site observations as a methodology for increasing forecast skill in prediction of large wind power ramps one or more hours ahead of their impact on a wind plant.  

SciTech Connect

ABSTRACT Application of Real-Time Offsite Measurements in Improved Short-Term Wind Ramp Prediction Skill Improved forecasting performance immediately preceding wind ramp events is of preeminent concern to most wind energy companies, system operators, and balancing authorities. The value of near real-time hub height-level wind data and more general meteorological measurements to short-term wind power forecasting is well understood. For some sites, access to onsite measured wind data - even historical - can reduce forecast error in the short-range to medium-range horizons by as much as 50%. Unfortunately, valuable free-stream wind measurements at tall tower are not typically available at most wind plants, thereby forcing wind forecasters to rely upon wind measurements below hub height and/or turbine nacelle anemometry. Free-stream measurements can be appropriately scaled to hub-height levels, using existing empirically-derived relationships that account for surface roughness and turbulence. But there is large uncertainty in these relationships for a given time of day and state of the boundary layer. Alternatively, forecasts can rely entirely on turbine anemometry measurements, though such measurements are themselves subject to wake effects that are not stationary. The void in free-stream hub-height level measurements of wind can be filled by remote sensing (e.g., sodar, lidar, and radar). However, the expense of such equipment may not be sustainable. There is a growing market for traditional anemometry on tall tower networks, maintained by third parties to the forecasting process (i.e., independent of forecasters and the forecast users). This study examines the value of offsite tall-tower data from the WINDataNOW Technology network for short-horizon wind power predictions at a wind farm in northern Montana. The presentation shall describe successful physical and statistical techniques for its application and the practicality of its application in an operational setting. It shall be demonstrated that when used properly, the real-time offsite measurements materially improve wind ramp capture and prediction statistics, when compared to traditional wind forecasting techniques and to a simple persistence model.

Martin Wilde, Principal Investigator

2012-12-31

230

Wind-Driven Gas Networks and Star Formation in Galaxies: Reaction-Advection Hydrodynamic Simulations  

E-print Network

The effects of wind-driven star formation feedback on the spatio-temporal organization of stars and gas in galaxies is studied using two-dimensional intermediate-representational quasi-hydrodynamical simulations. The model retains only a reduced subset of the physics, including mass and momentum conservation, fully nonlinear fluid advection, inelastic macroscopic interactions, threshold star formation, and momentum forcing by winds from young star clusters on the surrounding gas. Expanding shells of swept-up gas evolve through the action of fluid advection to form a ``turbulent'' network of interacting shell fragments whose overall appearance is a web of filaments (in two dimensions). A new star cluster is formed whenever the column density through a filament exceeds a critical threshold based on the gravitational instability criterion for an expanding shell, which then generates a new expanding shell after some time delay. A filament- finding algorithm is developed to locate the potential sites of new star formation. The major result is the dominance of multiple interactions between advectively-distorted shells in controlling the gas and star morphology, gas velocity distribution and mass spectrum of high mass density peaks, and the global star formation history. The gas morphology observations of gas in the LMC and in local molecular clouds. The frequency distribution of present-to-past average global star formation rate, the distribution of gas velocities in filaments (found to be exponential), and the cloud mass spectra (estimated using a structure tree method), are discussed in detail.

David Chappell; John Scalo

1999-04-28

231

Accurate Monitoring and Fault Detection in Wind Measuring Devices through Wireless Sensor Networks  

PubMed Central

Many wind energy projects report poor performance as low as 60% of the predicted performance. The reason for this is poor resource assessment and the use of new untested technologies and systems in remote locations. Predictions about the potential of an area for wind energy projects (through simulated models) may vary from the actual potential of the area. Hence, introducing accurate site assessment techniques will lead to accurate predictions of energy production from a particular area. We solve this problem by installing a Wireless Sensor Network (WSN) to periodically analyze the data from anemometers installed in that area. After comparative analysis of the acquired data, the anemometers transmit their readings through a WSN to the sink node for analysis. The sink node uses an iterative algorithm which sequentially detects any faulty anemometer and passes the details of the fault to the central system or main station. We apply the proposed technique in simulation as well as in practical implementation and study its accuracy by comparing the simulation results with experimental results to analyze the variation in the results obtained from both simulation model and implemented model. Simulation results show that the algorithm indicates faulty anemometers with high accuracy and low false alarm rate when as many as 25% of the anemometers become faulty. Experimental analysis shows that anemometers incorporating this solution are better assessed and performance level of implemented projects is increased above 86% of the simulated models. PMID:25421739

Khan, Komal Saifullah; Tariq, Muhammad

2014-01-01

232

Accurate monitoring and fault detection in wind measuring devices through wireless sensor networks.  

PubMed

Many wind energy projects report poor performance as low as 60% of the predicted performance. The reason for this is poor resource assessment and the use of new untested technologies and systems in remote locations. Predictions about the potential of an area for wind energy projects (through simulated models) may vary from the actual potential of the area. Hence, introducing accurate site assessment techniques will lead to accurate predictions of energy production from a particular area. We solve this problem by installing a Wireless Sensor Network (WSN) to periodically analyze the data from anemometers installed in that area. After comparative analysis of the acquired data, the anemometers transmit their readings through a WSN to the sink node for analysis. The sink node uses an iterative algorithm which sequentially detects any faulty anemometer and passes the details of the fault to the central system or main station. We apply the proposed technique in simulation as well as in practical implementation and study its accuracy by comparing the simulation results with experimental results to analyze the variation in the results obtained from both simulation model and implemented model. Simulation results show that the algorithm indicates faulty anemometers with high accuracy and low false alarm rate when as many as 25% of the anemometers become faulty. Experimental analysis shows that anemometers incorporating this solution are better assessed and performance level of implemented projects is increased above 86% of the simulated models. PMID:25421739

Khan, Komal Saifullah; Tariq, Muhammad

2014-01-01

233

SMUD Kokhala Power Tower Study  

SciTech Connect

Kokhala is the name of a new hybridized power tower design which integrates a nitrate-salt solar power tower with a gas turbine combined-cycle power plant. This integration achieves high value energy, low costs, and lower investor risk than a conventional solar only power tower plant. One of the primary advantages of this system is that it makes small power tower plants much more economically competitive with conventional power generation technologies. This paper is an overview of a study that performed a conceptual evaluation of a small (30 MWe) commercial plant suitable for the Sacramento Municipal Utility District`s (SMUD) Rancho Seco power plant site near Sacramento, California. This paper discusses the motivation for using a small hybrid solar plant and provides an overview of the analysis methodology used in the study. The results indicate that a power tower integrated with an advanced gas turbine, combined with Sacramento`s summer solar resource, could produce a low- risk, economically viable power generation project in the near future.

Price, Henry W. [National Renewable Energy Laboratory, Golden, CO (United States); Whitney, Daniel D.; Beebe, H.I. [Sacramento Municipal Utility District, CA (United States)

1997-06-01

234

Parametric study of tornado-type wind-energy systems  

SciTech Connect

The tornado-type wind energy system uses the pressure drop created by an intense vortex. The vortex is generated in a tower mounted at the turbine exit. The tower serves as a low pressure exhaust for the turbine. In a previous work, the author provided a numerical solution, using the two-equation (k-epsilon) turbulence model, of the tower flow with a uniform wind flow. Results compared favorably with measured values of pressure and showed a turbine diameter of approx. 0.4 times that of the tower to be optimum. In the present work, the author provides results to show the effects of embedding the tower in an atmospheric boundary layer, varying the tower height to diameter ratio, and varying tower diameter using the same system geometry and approach flow conditions. The results indicate a reduction of approx. 28% in power output

Ayad, S.S.

1981-10-01

235

Assessing Tower Flux Footprint Climatology and Scaling Between Remotely Sensed and Eddy Covariance Measurements  

NASA Astrophysics Data System (ADS)

We describe pragmatic and reliable methods to examine the influence of patch-scale heterogeneities on the uncertainty in long-term eddy-covariance (EC) carbon flux data and to scale between the carbon flux estimates derived from land surface optical remote sensing and directly derived from EC flux measurements on the basis of the assessment of footprint climatology. Three different aged Douglas-fir stands with EC flux towers located on Vancouver Island and part of the Fluxnet Canada Research Network were selected. Monthly, annual and interannual footprint climatologies, unweighted or weighted by carbon fluxes, were produced by a simple model based on an analytical solution of the Eulerian advection-diffusion equation. The dimensions and orientation of the flux footprint depended on the height of the measurement, surface roughness length, wind speed and direction, and atmospheric stability. The weighted footprint climatology varied with the different carbon flux components and was asymmetrically distributed around the tower, and its size and spatial structure significantly varied monthly, seasonally and inter-annually. Gross primary productivity (GPP) maps at 10-m resolution were produced using a tower-mounted multi-angular spectroradiometer, combined with the canopy structural information derived from airborne laser scanning (Lidar) data. The horizontal arrays of footprint climatology were superimposed on the 10-m-resolution GPP maps. Monthly and annual uncertainties in EC flux caused by variations in footprint climatology of the 59-year-old Douglas-fir stand were estimated to be approximately 15-20% based on a comparison of GPP estimates derived from EC and remote sensing measurements, and on sensor location bias analysis. The footprint-variation-induced uncertainty in long-term EC flux measurements was mainly dependent on the site spatial heterogeneity. The bias in carbon flux estimates using spatially-explicit ecological models or tower-based remote sensing at finer scales can be estimated by comparing the footprint-weighted and EC-derived flux estimates. This bias is useful for model parameter optimizing. The optimization of parameters in remote-sensing algorithms or ecosystem models using satellite data will, in turn, increase the accuracy in the upscaled regional carbon flux estimation.

Chen, Baozhang; Black, T. Andrew; Coops, Nicholas C.; Hilker, Thomas; (Tony) Trofymow, J. A.; Morgenstern, Kai

2009-02-01

236

Cooling tower windage: a new aspect to environmental assessment  

SciTech Connect

Results of the several investigations provided quantitative estimates of windage from Oak Ridge Gaseous Diffusion Plant cooling towers. Windage water deposited on the ground has the potential to reach nearby streams through runoff. Windage deposited on moisture depleted soils would not be significant. During winter months at Oak Ridge soils generally have a high moisture content such that windage deposition could be quickly transported as runoff. It is during this time that cooling towers are sometimes operated without fan-induced draft. Since windage water contains the same hexavalent chromium concentration (9 ppM) as the recirculating cooling water system, the runoff stream from the K-892J tower constitues a NPDES violation as an unpermitted discharge. As a long-term abatement strategy, concrete aprons were constructed along each side of new cooling towers at the Paducah, Kentucky Gaseous Diffusion Plant. The maximum distance of windage impact is wind dependent. If apron construction is envisioned as an abatement strategy at Oak Ridge, the maximum distance of impact can be inferred graphically from the several points where windage (fans off) and drift (fans on) loss curves intersect under the different meteorological conditions. Once the hexavalent chromium laden runoff stream reaches Poplar Creek, it is diluted well below the standards for drinking water and poses little potential for biological effects to aquatic systems.

Taylor, F.G.; Park, S.H.

1980-01-01

237

Income loss due to wind energy rejected by the Crete island electrical network – the present situation  

Microsoft Academic Search

During the last 4 years, a substantial wind energy penetration was encountered mainly in the Greek mainland. At the same time, limited size new wind-parks were built in the numerous Greek islands, although their wind potential is clearly higher than the one for the mainland and their wind energy generation could be used to replace electricity produced by diesel engines

J. K. Kaldellis; K. A. Kavadias; A. E. Filios; S. Garofallakis

2004-01-01

238

30 WS North Base Wind Study  

NASA Technical Reports Server (NTRS)

The 30 Weather Squadron (30 WS) is concerned about strong winds observed at their northern towers without advance warning. They state that terrain influences along the extreme northern fringes of Vandenberg Air Force Base (VAFB) make it difficult for forecasters to issue timely and accurate high wind warnings for northeasterly wind events. These events tend to occur during the winter or early spring when they are under the influence of the Great Basin high pressure weather regime. The Launch Weather Officers (LWOs) have seen these rapid wind increases in the current northern Towers 60, 70 and 71 in excess of their 35 kt operational warning threshold. For this task, the 30 WS requested the Applied Meteorology Unit (AMU) analyze data from days when these towers reported winds in excess of 35 kt and determine if there were any precursors in the observations that would allow the LWOs to better forecast and warn their operational customers for these wind events. The 30 WS provided wind tower data for the cool season (October - March) from the period January 2004-March 20 IO. The AMU decoded and evaluated the wind tower data for 66 days identified by the 30 WS as having high-wind events. Out of the 66 event days, only 30 had wind speed observations of > or =35 kt from at least one of the three northern towers. The AMU analyzed surface and upper air charts to determine the synoptic conditions for each event day along with tower peak wind speed and direction time series and wind rose charts for all 30 event days. The analysis revealed a trend on all event days in which the tower winds shifted to the northeast for a period of time before the first recorded > or =35 kt wind speed. The time periods for the 30 event days ranged from 20 minutes to several hours, with a median value of 110 minutes. This trend, if monitored, could give the 30 WS forecasters a precursor to assist in issuing an operational warning before a high wind event occurs. The AMU recommends developing a high-wind alert capability for VAFB using a local mesoscale model to forecast these wind events. The model should incorporate all of the VAFB local data sets and have a forecast capability of between 2 to 24 hours. Such a model would allow the meteorologists at VAFB to alert the operational customers of high wind events in a timely manner so protective action could be taken.

Wheeler, Mark

2011-01-01

239

Verification of BModes: Rotary Beam and Tower Modal Analysis Code; Preprint  

SciTech Connect

This paper describes verification of BModes, a finite-element code developed to provide coupled modes for the blades and tower of a wind turbine. The blades, which may be rotating or non-rotating, and the towers, whether onshore or offshore, are modeled using specialized 15-dof beam finite elements. Both blade and tower models allow a tip attachment, which is assumed to be rigid body with six moments of inertia, and a mass centroid that may be offset from the blade or tower axis. Examples of tip attachments are aerodynamic brakes for blades and nacelle-rotor subassembly for towers. BModes modeling allows for tower supports including tension wires, floating platforms, and monopiles on elastic foundations. Coupled modes (implying coupling of flap, lag, axial, and torsional motions) are required for modeling major flexible components in a modal-based, aeroelastic code such as FAST1. These are also required for validation of turbine models using experimental data, modal-based fatigue analysis, controls design, and understanding aeroelastic-stability behavior of turbines. Verification studies began with uniform tower models, with and without tip inertia, and progressed to realistic towers. For the floating turbine, we accounted for the effects of hydrodynamic inertia, hydrostatic restoring, and mooring lines stiffness. For the monopole-supported tower, we accounted for distributed hydrodynamic mass on the submerged part of the tower and for distributed foundation stiffness. Finally, we verified a model of a blade carrying tip mass and rotating at different speeds (verifications of other blade models, rotating or non-rotating, have been reported in another paper.) Verifications were performed by comparing BModes-generated modes with analytical results, if available, or with MSC.ADAMS results. All results in general show excellent agreement.

Bir, G.

2010-04-01

240

Cooling Towers--Energy Conservation Strategies  

E-print Network

COOLING TOWERS -- ENERGY CONSERVATION STRATEGIES Cooling Water Optimization Dr. JACK MATSON Environmental Engg. Dept. University of Houston Houston, Texas A cooling water system can be optimized by operating the cooling tower...

Matson, J.

241

Adaptive AI to play tower defense game  

Microsoft Academic Search

Adaptive algorithms give a way to solve a problem through successive attempts, without needing much information about a solution. The purpose of a tower defense game is to place towers that will kill enemies before they can reach the end of a fixed path. Using adaptive algorithms for a tower defense game allows the AI to not require any information

Paul A. Rummell

2011-01-01

242

Amazon Rain Forest Observation Tower  

USGS Multimedia Gallery

Sensors installed on this 213-foot (65-meter) tower  near Santarém, Brazil are used by USGS Geographer Dennis Dye and his U.S., Brazilian and Australian collaborators to investigate how seasonal variations in climate affects photosynthesis and the uptake of atmospheric carbon dioxide by ...

243

Multiple tendon compliant tower construction  

Microsoft Academic Search

In an offshore compliant tower construction, the combination is described of: an upper buoyancy module; a rigid stem of selected length fixedly attached to and extending below the upper buoyancy module to minimize rotation of the upper module; a lower base module; compliant means interconnecting the upper buoyancy module and the lower base module. It comprises: a composite assembly of

1988-01-01

244

View of Arizona rim towers from top of power plant. ...  

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

View of Arizona rim towers from top of power plant. Left tower supports Circuit 3, second tower from left supports Circuit 12, middle tower supports Circuit 10, second tower from right supports Circuit 9, and right tower supports Circuit 8, view southeast - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

245

View of first bank of circuit towers on Arizona side ...  

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

View of first bank of circuit towers on Arizona side of canyon. Left tower supports Circuit 12, second from left tower supports Circuit 11, middle tower supports Circuit 10, second from right tower supports Circuit 9, and right tower supports Circuit 8, view west - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

246

Wind-Wildlife Impacts Literature Database (WILD)(Fact Sheet)  

SciTech Connect

The Wind-Wildlife Impacts Literature Database (WILD), developed and maintained by the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL), is comprised of over 1,000 citations pertaining to the effects of land-based wind, offshore wind, marine and hydrokinetic, power lines, and communication and television towers on wildlife.

Not Available

2015-01-01

247

Quantifying the hurricane risk to offshore wind turbines  

E-print Network

Quantifying the hurricane risk to offshore wind turbines Stephen Rosea , Paulina Jaramilloa,1. Turbine tower buckling has been observed in typhoons, but no offshore wind turbines have yet been built be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind

Jaramillo, Paulina

248

Statement of Interest in a New Project, in response to PPARC call of April 26th FHIRN: A next-generation radio network for exploring the 3-dimensional solar wind  

E-print Network

-generation radio network for exploring the 3-dimensional solar wind Future Heliospheric Imaging Radio Network The solar wind is a supersonically-expanding extension of the solar atmosphere into interplanetary space of the solar wind controls the structure of the entire heliosphere, but direct measurements of the 3D solar

249

Wind for Schools Project Power System Brief, Wind Powering America Fact Sheet Series  

SciTech Connect

Wind Powering America's (WPA's) Wind for Schools project uses a basic system configuration for each school project. The system incorporates a single SkyStream wind turbine, a 70-ft guyed tower, disconnect boxes at the base of the turbine and at the school, and an interconnection to the school's electrical system. This document provides a detailed description of each system component.

Baring-Gould, I.

2009-05-01

250

Damage detection in carbon composite material typical of wind turbine blades using auto-associative neural networks  

NASA Astrophysics Data System (ADS)

The structure of a wind turbine blade plays a vital role in the mechanical and structural operation of the turbine. As new generations of offshore wind turbines are trying to achieve a leading role in the energy market, key challenges such as a reliable Structural Health Monitoring (SHM) of the blades is significant for the economic and structural efficiency of the wind energy. Fault diagnosis of wind turbine blades is a "grand challenge" due to their composite nature, weight and length. The damage detection procedure involves additional difficulties focused on aerodynamic loads, environmental conditions and gravitational loads. It will be shown that vibration dynamic response data combined with AANNs is a robust and powerful tool, offering on-line and real time damage prediction. In this study the features used for SHM are Frequency Response Functions (FRFs) acquired via experimental methods based on an LMS system by which identification of mode shapes and natural frequencies is accomplished. The methods used are statistical outlier analysis which allows a diagnosis of deviation from normality and an Auto-Associative Neural Network (AANN). Both of these techniques are trained by adopting the FRF data for normal and damage condition. The AANN is a method which has not yet been widely used in the condition monitoring of composite materials of blades. This paper is trying to introduce a new scheme for damage detection, localisation and severity assessment by adopting simple measurements such as FRFs and exploiting multilayer neural networks and outlier novelty detection.

Dervilis, N.; Barthorpe, R. J.; Antoniadou, I.; Staszewski, W. J.; Worden, K.

2012-04-01

251

Performance tests of tornado-type wind turbine models  

Microsoft Academic Search

Power coefficients C(p) and pressure distributions in the vortex tower were measured for two tornado-type wind turbine (TTWT) models (one a circular-shaped tower, the other a spiral) in a wind tunnel and in real environments. All of the maximum C(p) measured were greater than 1 and ranged from 4.7 to 15.2 times the Betz limit of the conventional wind generators.

C. T. Hsu; Ali Minachi

1990-01-01

252

Free and random vibrations of column-supported cooling towers  

NASA Astrophysics Data System (ADS)

A transfer matrix formulation is used to develop an efficient algorithm to analyze the dynamic behavior of a cooling-tower structure, which consists of a thin hyperbolic shell of revolution supported at the base by flexible columns. The paper is divided into three parts: (1) free vibration, (2) seismic excitation, and (3) wind excitation. The seismic effect is assumed to be dominated by the horizontal ground acceleration, modeled as an evolutionary random process. The wind pressure field is separated into a static part and a fluctuation part, the latter being modeled as a statistically stationary random field. Numerical examples are given to illustrate the application of the theory. In the case of wind excitation, surprising results are found that the fluctuation part of the structural response is not always dominated by the lowest frequency modes, contrary to common expectations.

Yong, Y.; Lin, Y. K.

1985-02-01

253

Interpolating wind speed normals from the sparse Dutch network to a high resolution  

E-print Network

, we had potential wind speed time series with 30 years of data (with at least 20 yearly and monthly by Verkaik (Verkaik, 2001). The method is a five-step procedure: 1 Use series of (potential) wind to calculate (potential) normals at measuring sites 2 Calculate wind speed normals at the top of the surface

Stoffelen, Ad

254

Analysis of a utility-interactive wind-photovoltaic hybrid system with battery storage using neural network  

NASA Astrophysics Data System (ADS)

This dissertation investigates the application of neural network theory to the analysis of a 4-kW Utility-interactive Wind-Photovoltaic System (WPS) with battery storage. The hybrid system comprises a 2.5-kW photovoltaic generator and a 1.5-kW wind turbine. The wind power generator produces power at variable speed and variable frequency (VSVF). The wind energy is converted into dc power by a controlled, tree-phase, full-wave, bridge rectifier. The PV power is maximized by a Maximum Power Point Tracker (MPPT), a dc-to-dc chopper, switching at a frequency of 45 kHz. The whole dc power of both subsystems is stored in the battery bank or conditioned by a single-phase self-commutated inverter to be sold to the utility at a predetermined amount. First, the PV is modeled using Artificial Neural Network (ANN). To reduce model uncertainty, the open-circuit voltage VOC and the short-circuit current ISC of the PV are chosen as model input variables of the ANN. These input variables have the advantage of incorporating the effects of the quantifiable and non-quantifiable environmental variants affecting the PV power. Then, a simplified way to predict accurately the dynamic responses of the grid-linked WPS to gusty winds using a Recurrent Neural Network (RNN) is investigated. The RNN is a single-output feedforward backpropagation network with external feedback, which allows past responses to be fed back to the network input. In the third step, a Radial Basis Functions (RBF) Network is used to analyze the effects of clouds on the Utility-Interactive WPS. Using the irradiance as input signal, the network models the effects of random cloud movement on the output current, the output voltage, the output power of the PV system, as well as the electrical output variables of the grid-linked inverter. Fourthly, using RNN, the combined effects of a random cloud and a wind gusts on the system are analyzed. For short period intervals, the wind speed and the solar radiation are considered as the sole sources of power, whose variations influence the system variables. Since both subsystems have different dynamics, their respective responses are expected to impact differently the whole system behavior. The dispatchability of the battery-supported system as well as its stability and reliability during gusts and/or cloud passage is also discussed. In the fifth step, the goal is to determine to what extent the overall power quality of the grid would be affected by a proliferation of Utility-interactive hybrid system and whether recourse to bulky or individual filtering and voltage controller is necessary. The final stage of the research includes a steady-state analysis of two-year operation (May 96--Apr 98) of the system, with a discussion on system reliability, on any loss of supply probability, and on the effects of the randomness in the wind and solar radiation upon the system design optimization.

Giraud, Francois

1999-10-01

255

Establishment of a Meso-network of Eddy Covariance Towers to Quantify Carbon, Water and Heat Fluxes Along a Permafrost and Climate Gradient in the Taiga Plains, Northwest Territories, Canada  

NASA Astrophysics Data System (ADS)

Recent research suggests an increase in active-layer depth in the continuous permafrost zone and degradation of the sporadic and discontinuous permafrost zones into seasonally frozen ground. Increasing active-layer depth and continued permafrost degradation will have far-reaching consequences for northern ecosystems with net feedbacks of unknown magnitude and direction to the climate system by altered regional hydrology and topography, vegetation composition and structure, land surface properties, and carbon dioxide (CO2) and methane (CH4) sink-source strengths. Several important questions are currently unanswered: 1) What is the net effect of permafrost thawing-induced biophysical and biogeochemical feedbacks to the climate system? 2) How do these two different types of feedback differ between the sporadic, discontinuous and continuous permafrost zones? 3) Is the decrease (increase) in net CO2 (CH4) exchange measured over mostly tundra sites in the continuous permafrost zone generalizable to forested landscapes in the sporadic, discontinuous and continuous permafrost zones? To address these questions we initiated a meso-network of eddy covariance towers to quantify carbon (CO2, CH4), water and heat fluxes along a permafrost and climate gradient in the Taiga Plains, Northwest Territories, Canada including the following four sites from south to north (Fort Simpson - Norman Wells - Inuvik): Scotty Creek (boreal forest-peatland landscape with sporadic/discontinuous permafrost; fully operational since May 2013), Norman Wells (boreal forest with discontinuous/continuous permafrost; to be established in 2014), Havikpak Creek (boreal forest with continuous permafrost; partly operational since April 2013) and Trail Valley Creek (tundra with continuous permafrost; partly operational since April 2013). At all sites the eddy covariance measurements are or will be complemented by repeated surveys of surface and frost table topography and vegetation, by land cover-type specific fluxes of CO2 and CH4 measured with a static chamber technique, and by remote sensing-based footprint analysis. With this contribution, we report on the current status of meso-network development and present results from the first growing season of eddy covariance measurements at Scotty Creek, Trail Valley Creek and Havikpak Creek. Net CO2 uptake started earlier and was more pronounced at the forested Havikpak site compared to the tundra site (Trail Valley Creek), which experienced similar air temperatures but later snow melt than Havikpak. Overall, Scotty Creek experienced the strongest net CO2 uptake but also the highest nighttime respiration. At the same time, meteorological conditions at Scotty Creek are markedly different with higher air temperatures and earlier snowmelt than at the two northern sites.

Sonnentag, O.; Helbig, M.; Detto, M.; Wischnewski, K.; Chasmer, L.; Marsh, P.; Quinton, W. L.

2013-12-01

256

Robust Fault Detection of Wind Energy Conversion Systems Based on Dynamic Neural Networks  

PubMed Central

Occurrence of faults in wind energy conversion systems (WECSs) is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS) is required. Recurrent neural networks (RNNs) have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate. PMID:24744774

Talebi, Nasser; Sadrnia, Mohammad Ali; Darabi, Ahmad

2014-01-01

257

Optimal operation management of fuel cell/wind/photovoltaic power sources connected to distribution networks  

NASA Astrophysics Data System (ADS)

In this paper a new multiobjective modified honey bee mating optimization (MHBMO) algorithm is presented to investigate the distribution feeder reconfiguration (DFR) problem considering renewable energy sources (RESs) (photovoltaics, fuel cell and wind energy) connected to the distribution network. The objective functions of the problem to be minimized are the electrical active power losses, the voltage deviations, the total electrical energy costs and the total emissions of RESs and substations. During the optimization process, the proposed algorithm finds a set of non-dominated (Pareto) optimal solutions which are stored in an external memory called repository. Since the objective functions investigated are not the same, a fuzzy clustering algorithm is utilized to handle the size of the repository in the specified limits. Moreover, a fuzzy-based decision maker is adopted to select the ‘best' compromised solution among the non-dominated optimal solutions of multiobjective optimization problem. In order to see the feasibility and effectiveness of the proposed algorithm, two standard distribution test systems are used as case studies.

Niknam, Taher; Kavousifard, Abdollah; Tabatabaei, Sajad; Aghaei, Jamshid

2011-10-01

258

Airport Remote Tower Sensor Systems  

NASA Technical Reports Server (NTRS)

Remote Tower Sensor Systems (RTSS) are proof-of-concept prototypes being developed by NASA/Ames Research Center (NASA/ARC) with collaboration with the FAA (Federal Aviation Administration) and NOAA (National Oceanic Atmospheric Administration). RTSS began with the deployment of an Airport Approach Zone Camera System that includes real-time weather observations at San Francisco International Airport. The goal of this research is to develop, deploy, and demonstrate remotely operated cameras and sensors at several major airport hubs and un-towered airports. RTSS can provide real-time weather observations of airport approach zone. RTSS will integrate and test airport sensor packages that will allow remote access to realtime airport conditions and aircraft status.

Papasin, Richard; Gawdiak, Yuri; Maluf, David A.; Leidich, Christopher; Tran, Peter B.

2001-01-01

259

Ozone Treatment For Cooling Towers  

NASA Technical Reports Server (NTRS)

Report presents results of study of cooling tower in which water treated with ozone instead of usual chemical agents. Bacteria and scale reduced without pollution and at low cost. Operating and maintenance costs with treatment about 30 percent of those of treatment by other chemicals. Corrosion rates no greater than with other chemicals. Advantage of ozone, even though poisonous, quickly detected by smell in very low concentrations.

Blackwelder, Rick; Baldwin, Leroy V.; Feeney, Ellen S.

1990-01-01

260

FLUX MEASUREMENTS FROM A TALL TOWER IN A COMPLEX LANDSCAPE  

SciTech Connect

The accuracy and representativeness of flux measurements from a tall tower in a complex landscape was assessed by examining the vertical and sector variability of the ratio of wind speed to momentum flux and the ratio of vertical advective to eddy flux of heat. The 30-60 m ratios were consistent with theoretical predictions which indicate well mixed flux footprints. Some variation with sector was observed that were consistent with upstream roughness. Vertical advection was negligible compared with vertical flux except for a few sectors at night. This implies minor influence from internal boundary layers. Flux accuracy is a function of sector and stability but 30-60 m fluxes were found to be generally representative of the surrounding landscape. This paper will study flux data from a 300 m tower, with 4 levels of instruments, in a complex landscape. The surrounding landscape will be characterized in terms of the variation in the ratio of mean wind speed to momentum flux as a function of height and wind direction. The importance of local advection will be assessed by comparing vertical advection with eddy fluxes for momentum and heat.

Kurzeja, R.; Weber, A.; Chiswell, S.; Parker, M.

2010-07-22

261

DETECTION OF CENTRIPETAL HEAT-ISLAND CIRCULATIONS FROM TOWER DATA IN ST. LOUIS  

EPA Science Inventory

Hourly averaged meteorological data gathered by a 25-tower network about St. Louis during 1976 are used in a search for centripetal circulations generated by the urban heat island. Considering data collected when the network resultant speed was less than 1.5 m/s, two data classes...

262

A comparison of CO2 and sensible heat flux measurements from aircraft and tower-based platforms  

Microsoft Academic Search

Eddy covariance fluxes of CO2 from a twin-engine Beechcraft Duchess were compared to the Ameriflux tower- based platform over a northern hardwood, deciduous forest between June 21 and July 24, 2006. Vertical wind was measured using a combination of a hemispherical pressure sensor probe and GPS\\/INS system on the aircraft and a sonic anemometer on the tower. The platforms employed

D. K. Martins; P. B. Shepson; M. Jacox; J. Smith; M. Hahn; S. Garrity; L. Vierling; H. P. Schmid; C. Vogel; J. R. Zimmerman; P. Wyss; R. Santini; B. Stirm

2006-01-01

263

Stability and Turbulence in the Atmospheric Boundary Layer: A Comparison of Remote Sensing and Tower Observations  

SciTech Connect

When monitoring winds and atmospheric stability for wind energy applications, remote sensing instruments present some advantages to in-situ instrumentation such as larger vertical extent, in some cases easy installation and maintenance, measurements of vertical humidity profiles throughout the boundary layer, and no restrictions on prevailing wind directions. In this study, we compare remote sensing devices, Windcube lidar and microwave radiometer, to meteorological in-situ tower measurements to demonstrate the accuracy of these measurements and to assess the utility of the remote sensing instruments in overcoming tower limitations. We compare temperature and wind observations, as well as calculations of Brunt-Vaisala frequency and Richardson numbers for the instrument deployment period in May-June 2011 at the U.S. Department of Energy National Renewable Energy Laboratory's National Wind Technology Center near Boulder, Colorado. The study reveals that a lidar and radiometer measure wind and temperature with the same accuracy as tower instruments, while also providing advantages for monitoring stability and turbulence. We demonstrate that the atmospheric stability is determined more accurately when the liquid-water mixing ratio derived from the vertical humidity profile is considered under moist-adiabatic conditions.

Friedrich, K.; Lundquist, J. K.; Aitken, M.; Kalina, E. A.; Marshall, R. F.

2012-01-01

264

Wind Measurements and Energy Potential for a Remote Village in Saudi Arabia  

Microsoft Academic Search

Site specific wind speed measurements are critical for techno-economical development of wind energy applications. This paper presents the wind power potential at Rawdat Ben Habbas village where meteorological measurements were made using a 40 meter tall wind tower for a period of one year. The wind speeds were recorded at 20, 30 and 40 meters above ground level (AGL) and

S. Rehman; I. M. El-Amin; S. Shaahid; A. Ahmad; F. Ahmad; T. Thabit

2007-01-01

265

24 m meteorological tower data report period: January through December, 1995  

SciTech Connect

This report was prepared by the Desert Research Institute (DRI) for the US Department of Energy (DOE). It summarizes meteorological data collected at the 24 meter tower at the Nevada Test Site Hazardous Material Spill Center (HAZMAT) located at Frenchman Flat near Mercury, Nevada, approximately 75 miles northwest of Las Vegas, Nevada. The tower was originally installed in July, 1993 to characterize baseline conditions for an EPA sponsored experimental research program at the HAZMAT. A previous report reported monitoring results for 1994. This report presents results of the monitoring for January--December, 1995, providing: a status of the measurement systems (including any quality assurance activities) during the report period and a summary of the meteorological conditions at the HAZMAT during the report period. The scope of the report is limited to summary data analyses and does not include extensive meteorological analysis. The tower was instrumented at 8 levels. Wind speed, wind direction, and temperature were measured at all 8 levels. Relative humidity was measured at 3 levels. Solar and net radiation were measured at 2 meters above the ground. Barometric pressure was measured at the base of the tower and soil temperature was measured near the base of the tower.

Freeman, D.; Bowen, J.B.; Egami, R.; Coulombe, W.; Crow, D.; Cristani, B.; Schmidt, S.

1997-12-01

266

Performance of tornado-type wind turbines with radial inflow supply  

SciTech Connect

Wind tunnel tests were conducted for the performance of tornado-type wind turbines with radial inflow supply from the incoming wind. It was shown that the radial inflow supply was necessary for intensifying a vortex in the wind collecting tower and, consequently, for enhancing the power efficiencies. A maximum power efficiency of 3.8 was obtained for a circular-shaped tower as compared to the value of 0.4 for the conventional windmills.

Hsu, C.T.; Ide, H.

1982-09-01

267

2. Abandoned light tower and keeper's house/light tower, view southeast, ...  

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

2. Abandoned light tower and keeper's house/light tower, view southeast, north northwest and west southwest sides - Matinicus Rock Light Station, Matinicus Island, on Matinicus Rock, Matinicus, Knox County, ME

268

1. Light tower/keeper's house and abandoned light tower, view northwest, ...  

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

1. Light tower/keeper's house and abandoned light tower, view northwest, south southeast and east northeast sides - Matinicus Rock Light Station, Matinicus Island, on Matinicus Rock, Matinicus, Knox County, ME

269

The Tower of Hanoi and finite automata  

E-print Network

Some of the algorithms for solving the Tower of Hanoi puzzle can be applied "with eyes closed" or "without memory". Here we survey the solution for the classical Tower of Hanoi that uses finite automata, as well as some variations on the original puzzle. In passing, we obtain a new result on morphisms generating the classical and the lazy Tower of Hanoi, and a new result on automatic sequences.

Allouche, Jean-Paul

2009-01-01

270

Application of NARX neural network in storm-time SYM-H index prediction from IMF and solar wind data  

NASA Astrophysics Data System (ADS)

In this study the NARX neural network has been used for the first time to predict high-resolution magnetic storm index of SYM-H from solar wind (SW) and IMF parameters. In total 73 great storm events with IMF/SW data available from ACE satellite during 1998 to 2006 are used to establish the ANN model. Out of them, 67 are used to train the network and the other 6 samples for test. Additionally, the NARX prediction model is also validated using IMF/SW data from WIND satellite for 7 great storms during 1995-1997 and 2005, as well as for the July 2000 Bastille day storm and November 2001 superstorm using Geotail and OMNI data at 1AU. Five interplanetary parameters of IMF Bz, By and total B components along with proton density and velocity of solar wind are used as the original external inputs of the neural network to predict the SYM-H index about one hour or an even longer time ahead. For the 6 test storms registered by ACE including two super-storms with minimum SYM-H less than -200 nT, the correlation coefficient between observed and NARX network predicted SYM-H is 0.95 as a whole, even as high as 0.95 and 0.98 with average relative variance of 13.2 percent and 7.4 percent for the two super-storms, respectively. The prediction for the 7 storms with WIND data is also satisfactory, showing averaged correlation coefficient about 0.91 and RMSE of 14.2 nT. The newly developed NARX model shows much better capability than Elman network for SYM-H prediction, which can partly be attributed to a key feedback to the input layer from the output neuron with a suitable length (about 120 min). This feedback means that nearly real information of the ring current status is effectively brought to taking part in the prediction of SYM-H index by ANN. The proper history length of the output-feedback may mainly reflect on average the characteristic time of ring current decay which involves various decay mechanisms with ion lifetimes from tens of minutes to tens of hours. Besides, it is verified that this kind of model is also capable of providing satisfactory predictions of the SYM-H index 3 hours ahead from IMF/SW data with less physical parameters observed at L1 position, enhancing significantly the practicality of the model in space weather forecasting.

Cai, Lei; Ma, S. Y.; Zhou, Yunliang; Cai, Hongtao

271

INL Wind Farm Project Description Document  

SciTech Connect

The INL Wind Farm project proposes to install a 20 MW to 40 MW wind farm on government property, consisting of approximately ten to twenty full-sized (80-meter hub height) towers with 2 MW turbines, and access roads. This includes identifying the optimal turbine locations, building access roads, and pouring the tower foundations in preparation for turbine installation. The project successfully identified a location on INL lands with commercially viable wind resources (i.e., greater than 11 mph sustained winds) for a 20 to 40 MW wind farm. Additionally, the proposed Wind Farm was evaluated against other General Plant Projects, General Purpose Capital Equipment projects, and Line Item Construction Projects at the INL to show the relative importance of the proposed Wind Farm project.

Gary Siefert

2009-07-01

272

Atmospheric LIDAR Provides Insight into Land Surface-Atmosphere Exchange at AmeriFlux Towers  

NASA Astrophysics Data System (ADS)

Lower levels of the planetary boundary layer (PBL) tend towards stable conditions at night with turbulent transfer of mass and energy exchange driven solely by mechanically forced turbulence, either from frictional forces near the ground or at the top of the plant canopy or from "top-down" forced intermittent bursts of turbulence generated from wind shear aloft. Nighttime mixing is further complicated by variable topography which creates complex wind flows including strong, along-valley-axis flows (wind direction shifts) and gravity-driven, mountain-valley flows that are particularly strong at night. Our estimates of terrestrial carbon sink or source magnitudes come primarily from flux towers which measure CO2, H2O, and energy exchange between the vegetated surface and the atmosphere with the eddy covariance technique. Flux towers are usually equipped with instrumentation only to the top of the plant canopy or a few meters above, although in reality, nocturnal wind shear can be strong well above the canopy and produce turbulent eddies which intermittently penetrate the canopy. The structures and drivers of these "top-down" forced events are currently being missed at most flux towers due to lack of instrumentation above the canopy. Here, we present over 800 hours of wind flow observations above two tree canopies for understanding nighttime turbulent transfer. Measurements of wind speed, direction and turbulence were taken with a Laser Detection and Ranging (LIDAR) instrument, co-located at the Tonzi AmeriFlux tower, California and the Wind River AmeriFlux tower, Washington. LIDAR provided high-resolution vertical profiles of wind shear and turbulence up to 200 m above the surface. To assess the contribution of turbulent transport to net ecosystem exchange, we assume that the efficiency of turbulence to transport mass and energy can be represented by the magnitude of turbulent kinetic energy (TKE). Although there are limitations to calculating accurate turbulence measurements from LIDAR, as will be discussed, LIDAR does provide observations well above the canopy for identifying drivers of "top-down" forced turbulence. Here, we show evidence of these intermittent turbulent bursts and identify times when they penetrate the plant canopy and influence CO2 exchange. At the Tonzi AmeriFlux tower, we also show evidence of advective flows driven by complex terrain to the east. The contribution of advective terms to CO2 exchange is often ignored in the carbon flux budget although we provide evidence that it should be considered even at sites with gentle local terrain. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Wharton, S.; Osuna, J. L.; Newman, J.; Falk, M.; Baldocchi, D. D.; Bible, K.

2012-12-01

273

Wind tunnel tests of a free yawing downwind wind turbine  

NASA Astrophysics Data System (ADS)

This research paper presents preliminary results on a behavioural study of a free yawing downwind wind turbine. A series of wind tunnel tests was performed at the TU Delft Open Jet Facility with a three bladed downwind wind turbine and a rotor radius of 0.8 meters. The setup includes an off the shelf three bladed hub, nacelle and generator on which relatively flexible blades are mounted. The tower support structure has free yawing capabilities provided at the base. A short overview on the technical details of the experiment is given as well as a brief summary of the design process. The discussed test cases show that the turbine is stable while operating in free yawing conditions. Further, the effect of the tower shadow passage on the blade flapwise strain measurement is evaluated. Finally, data from the experiment is compared with preliminary simulations using DTU Wind Energy's aeroelastic simulation program HAWC2.

Verelst, D. R. S.; Larsen, T. J.; van Wingerden, J. W.

2014-12-01

274

Protection from ground faults in the stator winding of generators at power plants in the Siberian networks  

SciTech Connect

The experience of many years of experience in developing and utilization of ground fault protection in the stator winding of generators in the Siberian networks is generalized. The main method of protection is to apply a direct current or an alternating current with a frequency of 25 Hz to the primary circuits of the stator. A direct current is applied to turbo generators operating in a unit with a transformer without a resistive coupling to the external grid or to other generators. Applying a 25 Hz control current is appropriate for power generation systems with compensation of a capacitive short circuit current to ground. This method forms the basis for protection of generators operating on busbars, hydroelectric generators with a neutral grounded through an arc-suppression reactor, including in consolidated units with generators operating in parallel on a single low-voltage transformer winding.

Vainshtein, R. A., E-mail: vra@tpu.ru [Tomsk Polytechnical University (Russian Federation); Lapin, V. I. [ODU Sibiri (Integrated Dispatcher Control for Siberia), branch of JSC 'SO EES' (Russian Federation); Naumov, A. M.; Doronin, A. V. [JSC NPP 'EKRA' (Russian Federation); Yudin, S. M. [Tomsk Polytechnical University (Russian Federation)

2010-05-15

275

Sustainable Energy Solutions Task 1.0: Networked Monitoring and Control of Small Interconnected Wind Energy Systems  

SciTech Connect

EXECUTIVE SUMARRY This report presents accomplishments, results, and future work for one task of five in the Wichita State University Sustainable Energy Solutions Project: To develop a scale model laboratory distribution system for research into questions that arise from networked control and monitoring of low-wind energy systems connected to the AC distribution system. The lab models developed under this task are located in the Electric Power Quality Lab in the Engineering Research Building on the Wichita State University campus. The lab system consists of four parts: 1. A doubly-fed induction generator 2. A wind turbine emulator 3. A solar photovoltaic emulator, with battery energy storage 4. Distribution transformers, lines, and other components, and wireless and wired communications and control These lab elements will be interconnected and will function together to form a complete testbed for distributed resource monitoring and control strategies and smart grid applications testing. Development of the lab system will continue beyond this project.

Janet.twomey@wichita.edu

2010-04-30

276

7th International Workshop on Large-Scale Integration of Wind Power and on Transmission Networks for Offshore Wind Farms Models for HLI analysis of power systems with  

E-print Network

for Offshore Wind Farms 1 Models for HLI analysis of power systems with offshore wind farms and distributed power plants, distributed generation and offshore wind farms. Particular attention is paid to the latter influence of offshore wind generation on power system operation and planning, a growing interest is paid

Bak-Jensen, Birgitte

277

Design and Construction of a Scaled Whirl Tower Facility  

NASA Astrophysics Data System (ADS)

Experimental development of helicopter rotors requires centrifugal testing before entry into a wind tunnel or flight test campaign. This centrifugal testing is performed on test rigs called whirl towers. These facilities are very rare, in fact there were none available in Canada at the time of writing this thesis, but they are very valuable experimental research tools. This thesis describes the design and construction of a whirl tower facility for the centrifugal testing of scaled helicopter rotors with actively controlled systems for reducing vibration. First, the trade-offs between the desired capabilities for the facility to be designed are reviewed, leading to the identification of a set of design requirements. Following this, various concepts for the drive system, frame, data acquisition, and safety infrastructure are proposed. From these, a final design is assembled, whose main advantage is its flexibility and robustness for developmental research. The whirl tower is capable of testing single or multi-bladed rotors (up to four blades), with blades between 1.0 and 1.6 m radius, up to 1,800 RPM frequency with no 'dead zones'. The whirl tower is equipped with a 60 HP, 575 V, AC motor, with flexible coupling and direct drive to the scaled rotor hub. The facility also features a digital telemetry system, slip rings for power and signal transmission for active control, interchangeable rotor heads with variable root distance, and a containment wall for protection from possible rotor blade failures. The manufacturing and construction of the facility, as well as its installation at the National Research Council in Ottawa, is described in detail.

Pickard, John Alexander

278

Fiber Optic Sensor Network for Lightning Impact Localization and Classification in Wind Turbines  

Microsoft Academic Search

As wind turbines are increasing both in number and in height, they are exposed to a major threat in form of lightning strikes. The protection of these structures from the effects of lightning is an important issue in today's wind turbine development. However, as lightning is random in nature, a complete protection against its damages is not achievable. The presented

Sebastian G. M. KrFernando; Fernando Puente Leon; Benoit Appert

2006-01-01

279

Cooling Tower Inspection with Scuba  

E-print Network

in preparation for repainting. Over the 20-year life of this cooling tower, repainting has probably occurred at least half a dozen times. Our big concern, of course, was: How did all this material get past the suction screens? Do the screens have holes... the wall of the sump horizontally and curves down ward toward the bottom of the sump. The open end of each suction line is fitted with a five foot diameter, screened basket. The screen openings are about 3/4" square. The sump is separated into four (4...

Brenner, W.

1982-01-01

280

Multiple tendon compliant tower construction  

SciTech Connect

In an offshore compliant tower construction, the combination is described of: an upper buoyancy module; a rigid stem of selected length fixedly attached to and extending below the upper buoyancy module to minimize rotation of the upper module; a lower base module; compliant means interconnecting the upper buoyancy module and the lower base module. It comprises: a composite assembly of elongated continuous structural members arranged in parallel independent separate relation and moveable relative to each other. The structural members have lower end portions with bottom ends fixed to the lower base module and upper end portions extending into the upper module and with upper ends fixed to the upper module.

Horton, E.E.

1988-04-26

281

Wind turbine spoiler  

DOEpatents

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.

Sullivan, William N. (Albuquerque, NM)

1985-01-01

282

Resolution of tower shadow models for downwind mounted rotors and its effects on the blade fatigue  

NASA Astrophysics Data System (ADS)

A simulation study on the wind field resolution in computer load simulations has been conducted, both in transversal/vertical and longitudinal direction, to determine the effect on blade fatigue loading. Increasing the transversal/vertical resolution decreased the loading significantly, while only small changes to the load, at very low frequencies were found for increased longitudinal resolution. Next the influence of the tower shadow for a downwind mounted rotor was investigated, with respect to blade fatigue loading. The influence of different components to the total tower shadow effect was studied, both for a monopile and a truss tower, latter at inclination 0 and 22.5 degrees with respect to the incoming wind direction. Four components were considered, both individually and in combinations: mean wind speed, mean velocity deficit, unsteady motions from vortex shedding, and turbulence. The mean velocity deficit and turbulence were the main contributors to blade fatigue loading, and the unsteady motions can be neglected for the truss tower. For the monopile, neglecting the unsteady motions resulted in an underestimation of fatigue loading in the order of 3 percent.

Reiso, M.; Muskulus, M.

2014-12-01

283

78 FR 17183 - Information Collection: Grey Towers Visitor Comment Card  

Federal Register 2010, 2011, 2012, 2013, 2014

...Grey Towers Visitor Comment Card AGENCY: Forest Service, USDA...Grey Towers Visitor Comment Card'' with 0596-0226, ``Forest...Historic Site during normal business hours. Visitors are encouraged...Grey Towers Visitor Comment Card. OMB Number:...

2013-03-20

284

View second bank of circuit towers on Arizona side of ...  

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

View second bank of circuit towers on Arizona side of canyon. Left tower supports Circuit 10 and right tower supports Circuit 11, view north - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

285

Coupled Dynamic Analysis of Multiple Unit Floating Offshore Wind Turbine  

E-print Network

In the present study, a numerical simulation tool has been developed for the rotor-floater-tether coupled dynamic analysis of Multiple Unit Floating Offshore Wind Turbine (MUFOWT) in the time domain including aero-blade-tower dynamics and control...

Bae, Yoon Hyeok

2013-04-23

286

Cooling Towers, The Neglected Energy Resource  

E-print Network

towers: 1) are just as important a link in the chain as the other equipment; 2) are an important source of energy conservation; 3) can be big money makers; 4) operators should be aware of the potential of maximising cold water. Most towers were designed...

Burger, R.

287

Scientist Preparing to Climb Observation Tower  

USGS Multimedia Gallery

USGS collaborator Scott Saleska (University of Arizona) prepares to climb a 213-foot (65-meter) tower at the Amazon forest study site near Santarém, Brazil.  Saleska and other team members installed a remote sensing system near the top of the tower as part of an investigation to improve ...

288

COKE QUENCH TOWER EMISSION TESTING PROGRAM  

EPA Science Inventory

The report gives results of a field study to further define quench tower organic emissions, the character and magnitude of which are virtually unknown. (Limited testing in 1976 indicated that a large quantity of organic material was emitted from quench towers, but these data were...

289

View of first bank of circuit towers on Arizona side ...  

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

View of first bank of circuit towers on Arizona side of canyon. Photograph taken from Nevada side of canyon. Left tower supports Circuit 8, second from left tower supports Circuit 9, middle tower supports Circuit 10, second from right tower supports Circuit 11, and right tower supports Circuit 12, view southeast. - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

290

View of the penitentiary complex and central guard tower, looking ...  

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

View of the penitentiary complex and central guard tower, looking from the administration building tower, facing north - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

291

Parametric evaluation of wind turbine noise  

SciTech Connect

In lieu of large single wind turbine installations, US Windpower, Burlington, Massachusetts is promoting the wind farm concept for wind power generation. A wind farm is an array of several small machines which are used to produce the equipment power of a single, large wind turbine. The smaller 50 KW machines manufactured by US Windpower, when used in an array to produce a large quantity of power, minimize the incidence of annoying infrasonic pulsing, nevertheless, the production of low frequency sound by wind farms still occurs. Measurements and theory clearly demonstrate that blade passage through the tower wake produces a sound pressure level frequency spectra consisting of harmonics of the blade passage frequency. The chief purpose of this work is to identify the importance of various tower and blade parameters that control blade passage noise generation.

Tocci, G.C.; Marcus, E.N.

1982-01-01

292

Augmented Reality Tower Technology Assessment  

NASA Technical Reports Server (NTRS)

Augmented Reality technology may help improve Air Traffic Control Tower efficiency and safety during low-visibility conditions. This paper presents the assessments of five off-duty controllers who shadow-controlled' with an augmented reality prototype in their own facility. Initial studies indicated unanimous agreement that this technology is potentially beneficial, though the prototype used in the study was not adequate for operational use. Some controllers agreed that augmented reality technology improved situational awareness, had potential to benefit clearance, control, and coordination tasks and duties and could be very useful for acquiring aircraft and weather information, particularly aircraft location, heading, and identification. The strongest objections to the prototype used in this study were directed at aircraft registration errors, unacceptable optical transparency, insufficient display performance in sunlight, inadequate representation of the static environment and insufficient symbology.

Reisman, Ronald J.; Brown, David M.

2009-01-01

293

A comparison of CO2 and sensible heat flux measurements from aircraft and tower-based platforms  

NASA Astrophysics Data System (ADS)

Eddy covariance fluxes of CO2 from a twin-engine Beechcraft Duchess were compared to the Ameriflux tower- based platform over a northern hardwood, deciduous forest between June 21 and July 24, 2006. Vertical wind was measured using a combination of a hemispherical pressure sensor probe and GPS/INS system on the aircraft and a sonic anemometer on the tower. The platforms employed NDIR analyzers to measure CO2 concentrations. Six flight legs, 5km in length, were averaged at heights of 150, 210, and 275m and compared with 30min averaged CO2 and sensible heat fluxes at the top of the 46m flux tower. Aircraft-based flux measurements as a function of altitude allow for assessment of flux divergence. In this paper, we compare the aircraft and tower data sets, and assess the differences in averaged fluxes, based in part on the footprint of the two platforms and flux divergence.

Martins, D. K.; Shepson, P. B.; Jacox, M.; Smith, J.; Hahn, M.; Garrity, S.; Vierling, L.; Schmid, H. P.; Vogel, C.; Zimmerman, J. R.; Wyss, P.; Santini, R.; Stirm, B.

2006-12-01

294

International Snow Science Workshop Grenoble Chamonix Mont-Blanc -2013 Wind and snow particle distribution in powder snow cloud  

E-print Network

measurements of both wind and snow particles in the powder snow cloud were made to investigate the powder part.s.l.). On the tower, Load cells and velocity sensors using a set of optical sensors (Dent et al., 1998) were installed-dimensional wind direction and speed in Figure 1. View of the avalanche test site. The measurement tower is located

Paris-Sud XI, Université de

295

Sliding mode control of wind energy systems with DOIG-power efficiency and torsional dynamics optimization  

Microsoft Academic Search

Wind turbines with double output induction generators can operate at variable speed permitting conversion efficiency maximization over a wide range of wind velocities. However, random wind fluctuations, wind shear and tower shadow, may excite the oscillation mode of the mechanical system, producing large torque ripple. Consequently, damage to drive train components and power quality problems may occur. In this paper,

H. De Battista; P. F. Puleston; R. J. Mantz; C. F. Christiansen

2000-01-01

296

Concept selection, optimization, and preliminary design of large wind generators  

NASA Technical Reports Server (NTRS)

The development of the conceptual design of high (1000 kW, 18 mph mean wind speed site) and low (100 kW, 12 mph site) power wind generator systems to be integrated into a standard electric utility is discussed. Analyses leading to the selection of the rotor and tower design are outlined. The 1000 kW system selected for further development utilizes an all composite rotor blade design and a steel shell tower. The projected energy cost is 3.5 cents/kW hr. Results of optimization of the rated power, site wind speed, and rated wind speed parameters are summarized.

Meier, R. C.

1975-01-01

297

Neural systems engaged by planning: a PET study of the Tower of London task  

Microsoft Academic Search

The functional anatomy of planning was investigated using the Tower of London task. Activation was observed in a distributed network of cortical areas incorporating prefrontal, cingulate, premotor, parietal and occipital cortices. Activation in corresponding areas has been observed in visuospatial working memory tasks with the exception of the rostral prefrontal cortex. This area may be identified with the executive components

S. C. Baker; R. D. Rogers; A. M. Owen; C. D. Frith; R. J. Dolan; R. S. J. Frackowiak; T. W. Robbins

1996-01-01

298

5. View of south tower, facing northnortheast from south bank ...  

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

5. View of south tower, facing north-northeast from south bank of the Columbia River. Center tower and north tower in background, lower right. - Pasco-Kennewick Transmission Line, Columbia River Crossing Towers, Columbia Drive & Gum Street, Kennewick, Benton County, WA

299

Multistory transmission tower model for lightning surge analysis  

Microsoft Academic Search

Transmission towers have been modeled for lightning surge analysis based on the measurements on the towers alone. For an actual high voltage transmission tower, however, ground wires are equipped in many cases. This paper proposes a multistory transmission tower model to be used in the multi-conductor analysis by EMTP. The circuit parameters of the model are determined based on the

M. Ishii; T. Kawamura; T. Kouno; E. Ohsaki; K. Shiokawa; K. Murotani; T. Higuchi

1991-01-01

300

View of Nevada rim towers from top of power plant. ...  

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

View of Nevada rim towers from top of power plant. Left tower supports Circuits 7 and 14, middle tower supports Circuit 6, and right tower supports Circuit 5, view west - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

301

View of second bank of circuit towers on Arizona side ...  

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

View of second bank of circuit towers on Arizona side of canyon. Left tower supports Circuit 8, middle tower supports Circuit 9, and right tower supports Circuit 10, view northwest - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

302

Description of the Columbia Basin Wind Energy Study (CBWES)  

SciTech Connect

The purpose of this Technical Report is to provide background information about the Columbia Basin Wind Energy Study (CBWES). This study, which was supported by the U.S. Department of Energy’s Wind and Water Power Program, was conducted from 16 November 2010 through 21 March 2012 at a field site in northeastern Oregon. The primary goal of the study was to provide profiles of wind speed and wind direction over the depth of the boundary layer in an operating wind farm located in an area of complex terrain. Measurements from propeller and vane anemometers mounted on a 62 m tall tower, Doppler Sodar, and Radar Wind Profiler were combined into a single data product to provide the best estimate of the winds above the site during the first part of CBWES. An additional goal of the study was to provide measurements of Turbulence Kinetic Energy (TKE) near the surface. To address this specific goal, sonic anemometers were mounted at two heights on the 62 m tower on 23 April 2011. Prior to the deployment of the sonic anemometers on the tall tower, a single sonic anemometer was deployed on a short tower 3.1 m tall that was located just to the south of the radar wind profiler. Data from the radar wind profiler, as well as the wind profile data product are available from the Atmospheric Radiation Measurements (ARM) Data Archive (http://www.arm.gov/data/campaigns). Data from the sonic anemometers are available from the authors.

Berg, Larry K.; Pekour, Mikhail S.; Nelson, Danny A.

2012-10-01

303

Impacts of grid integration of wind energy in the Namibian power network  

Microsoft Academic Search

This paper discusses the general impact of grid integration of wind energy in the Namibian context. The paper focuses on the current electricity situation in Namibia, which presents a demanding task to energy and power engineers in the country to develop ways of rescuing the dire electricity need for Namibia's nation. The efforts made by the country's power utility, NamPower

A. I. Elombo; S. P. Chowdhury; H. J. Vermeulen

2010-01-01

304

Wind for Schools Project Power System Brief  

SciTech Connect

This fact sheet provides an overview of the system components of a Wind Powering America Wind for Schools project. Wind Powering America's (WPA's) Wind for Schools project uses a basic system configuration for each school project. The system incorporates a single SkyStream(TM) wind turbine, a 70-ft guyed tower, disconnect boxes at the base of the turbine and at the school, and an interconnection to the school's electrical system. A detailed description of each system component is provided in this document.

Not Available

2007-08-01

305

Extending Winding Capacitance Cancellation to Three-Phase EMC Input Filter Networks  

Microsoft Academic Search

Techniques have been presented in the literature for canceling stray capacitances for inductors in single-phase power filters. With the same aim, the flexibility of three-phase networks is here explored. A thorough theoretical analysis is presented, where pros and cons of parasitic cancellation networks are highlighted and improvements are proposed. A systematic mathematical procedure to evaluate impedances for different noise modes

Marcelo L. Heldwein; Johann W. Kolar

2007-01-01

306

Aquarius: Tower Rollback - Duration: 2:14.  

NASA Video Gallery

The mobile service tower at NASA's Launch Complex-2 at Vandenberg Air Force Base in California is being moved away from the ULA Delta II rocket with the Aquarius/SAC-D spacecraft atop, in preparati...

307

Cooling Towers, The Neglected Energy Resource  

E-print Network

inefficiently engineered due to cheap power and the "low bidder" syndrome. Operating energy costs were ignored and purchasing criteria was to award the contract to the lowest bidder. This paper investigates internal elements of typical towers, delineates...

Burger, R.

1985-01-01

308

Advanced wet-dry cooling tower concept  

E-print Network

The purpose of this years' work has been to test and analyze the new dry cooling tower surface previously developed. The model heat transfer test apparatus built last year has been instrumented for temperature, humidity ...

Snyder, Troxell Kimmel

309

Ozone inhibits corrosion in cooling towers  

NASA Technical Reports Server (NTRS)

Commercially available corona discharge ozone generator, fitted onto industrial cooling tower, significantly reduces formation of scales (calcium carbonate) and corrosion. System also controls growth of algae and other microorganisms. Modification lowers cost and improves life of cooling system.

French, K. R.; Howe, R. D.; Humphrey, M. F.

1980-01-01

310

The Tower of London bomb explosion.  

PubMed Central

After the detonation of a bomb in the Tower of London 37 people were brought to St. Bartholomew's Hospital. The explosion caused numerous severe injuries of a type rarely seen in peacetime. PMID:1148778

Tucker, K; Lettin, A

1975-01-01

311

Soaring Towers: Building with Recycled Materials  

NSDL National Science Digital Library

In this activity, learners will build the highest tower they can out of recycled materials. As they work on this activity, they explore which shapes and sizes make good tower bases, which work well in the middle, and how to make sure the configuration is stable, even when some of the shapes are quite irregular. Available as a web page, downloadable pdf, and in Spanish.

Terc

2010-01-01

312

27 HELICAL ANCHORS AS WIND TOWER GUYED CABLE FOUNDATIONS  

Microsoft Academic Search

SUMMARY: The current research is dedicated to developing design parameters and installation charts for the use of helical anchor foundation elements in application with 1 to 10 kW guyed and free standing turbines. The effects that dynamic loading and varying water table conditions have on the pullout capacity of helical anchors are the focus topics of this research. This study

R. T. VICTOR; A. B. CERATO

313

Proceedings Nordic Wind Power Conference  

E-print Network

Nordic Wind Power Conference Risø National Laboratory 1-2 November 2007 Department: Wind Energy 2/2 Grid faults impact on wind turbine structural loads Network topology considerations when Forecast Error State of the art of methodology to assess impacts of large amounts of wind power on design

314

A review of the SERI wind energy innovative systems program  

Microsoft Academic Search

Features of innovative wind energy conversion systems evaluated and\\/or tested at the Solar Energy Research Institute are reviewed. Cost, performance, and engineering data were acquired for the machines, along with proof-of-concept demonstrations. Machines which were examined included a straight-bladed vertical axis wind turbine with circulation controlled airfoils, the Grumman tornado wind energy tower with louvers, a wind-powered charged aerosol generator

I. E. Vas; P. South

1980-01-01

315

Wind energy integration into 110 kV system - impact on power quality of MV and LV networks  

Microsoft Academic Search

The amount of electrical energy produced by wind farms is constantly increasing. Nowadays detailed analyses considering the impact of wind energy integration on the transmission system are required. Therefore several wind impact studies have been carried out lately in different countries. The conclusions of these studies are related to different aspects of wind power, such as its fluctuating nature, distributed

E. Vilchez; J. Stenzel

2008-01-01

316

On the design and feasibility of a pneumatically supported actively guided space tower  

NASA Astrophysics Data System (ADS)

Space tethers have been investigated widely as a means to provide easy access to space. However, the design and construction of such a device presents significant unsolved technological challenges. An alternative approach is proposed to the construction of a space elevator that utilises a free-standing core structure to provide access to near space regions and to reduce the cost of space launch. The theoretical and experimental investigation of the bending of inflatable cylindrical cantilevered beams made of modem fabric materials provides the basis for the design of an inflatable space tower. Experimental model structures were deployed and tested in order to determine design guidelines for the core structure. The feasibility of the construction of a thin walled inflatable space tower of 20 km vertical extent comprised of pneumatically inflated sections that are actively controlled and stabilised to balance external disturbances and support the structure is discussed. The response of the structure under wind loads is analyzed and taken into account for determining design guidelines. Such an approach avoids problems associated with a space tether including material strength constraints, the need for in-space construction, the fabrication of a cable at least 50,000 km in length, and the ageing and meteorite damage effects associated with a thin tether or cable in Low Earth Orbit. A suborbital tower of 20 km height would provide an ideal mounting point where a geostationary orbital space tether could be attached without experiencing atmospheric turbulence and weathering in the lower atmosphere. The tower can be utilized as a platform for various scientific and space missions or as an elevator to carry payloads and tourists. In addition, space towers can significantly be utilized to generate electrical power by harvesting high altitude renewable energy sources. Keywords: Space Elevator, Inflatable Space Tower, Inflatable Structure, Inflatable Beam, Inflatable Multiple-beam Structure, Cantilevered Beam, Pneumatic Structures.

Seth, Raj Kumar

2010-07-01

317

29 CFR 1926.1435 - Tower cranes.  

Code of Federal Regulations, 2012 CFR

...static undercarriages. (iii) Wind speed. Wind must not exceed the speed recommended...in the event of pressure loss or power failure, are required: (A...approaching the upper limits. (v) Wind speed indicator. A device...

2012-07-01

318

29 CFR 1926.1435 - Tower cranes.  

Code of Federal Regulations, 2014 CFR

...static undercarriages. (iii) Wind speed. Wind must not exceed the speed recommended...in the event of pressure loss or power failure, are required: (A...approaching the upper limits. (v) Wind speed indicator. A device...

2014-07-01

319

29 CFR 1926.1435 - Tower cranes.  

Code of Federal Regulations, 2011 CFR

...static undercarriages. (iii) Wind speed. Wind must not exceed the speed recommended...in the event of pressure loss or power failure, are required: (A...approaching the upper limits. (v) Wind speed indicator. A device...

2011-07-01

320

29 CFR 1926.1435 - Tower cranes.  

Code of Federal Regulations, 2013 CFR

...static undercarriages. (iii) Wind speed. Wind must not exceed the speed recommended...in the event of pressure loss or power failure, are required: (A...approaching the upper limits. (v) Wind speed indicator. A device...

2013-07-01

321

Characteristics of Winter Lightning that Occurred on a Windmill and its Lightning Protection Tower  

NASA Astrophysics Data System (ADS)

We have obtained the electric current, electric field change, and optical image data or several tens of lightning that hit on a wind turbine and its lightning-protection tower during the past6 non-stop winter seasons from 2005 to 2010. By analyzing the data, we found that the upward lightning hitting on the high structures can be classified into self-initiated and other-triggered types according to whether there is a discharge activity prior to the upward lightning. We also found that although other-triggered upward lightning can start at a relatively lower wind speed, self-initiated upward lightning always started either from the stationary tower under a larger wind speed or from a rotating wind turbine blade. It appears that the wind and by inference the corona discharge shielding do have considerable effect in the initiation of an upward leader. Regarding the initial progression of a positive leader, we found a systematic difference in the speeds of the leaders from the structures that have remarkably different heights. Finally, we discussed the pulse discharges observed in the very initial stages of positive upward leaders and also how to forecast direct strike of upward lightning.

Takagi, Nobuyuki; Wang, Daohong

322

Characteristics of Winter Lightning that Occurred on a Windmill and its Lightning Protection Tower in Japan  

NASA Astrophysics Data System (ADS)

We have observed lightning that struck a wind turbine and its neighboring lightning-protection tower during the past six winter seasons (2005 to 2010) using various lightning observation instruments. Our results show that the upward lightning from high structures can be classified into self-initiated and other-triggered types according to whether there is a discharge activity prior to the upward lightning. Furthermore, we found that although other-triggered upward lightning can start at a relatively low wind speed, self-initiated upward lightning always started either from the stationary tower under a larger wind speeds or from a rotating wind turbine blade. It appears that the wind does have considerable effect in assisting the initiation of an upward leader. In addition, we found that the self-initiated upward positive leaders from structures with different effective heights exhibited remarkably different initial speeds. Higher structures tend to initiate faster upward leaders. Finally, we discussed the pulse discharges observed in the very initial stages of positive upward leaders and how to protect structures from upward lightning as well.

Wang, Daohong; Takagi, Nobuyuki

323

Wind Turbine Safety and Function Test Report for the Gaia-Wind 11-kW Wind Turbine  

SciTech Connect

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers to wind energy expansion by providing independent testing results for small wind turbines (SWT). In total, four turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests performed on the turbines, including power performance, duration, noise, and power-quality tests. The results of the testing provide the manufacturers with reports that can be used for small wind turbine certification. The test equipment includes a Gaia-Wind 11-kW wind turbine mounted on an 18-m monopole tower. Gaia-Wind Ltd. manufactured the turbine in Denmark. The system was installed by the NWTC site operations group with guidance and assistance from Gaia-Wind.

Huskey, A.; Bowen, A.; Jager, D.

2010-01-01

324

Comprehensive study of drift from mechanical draft cooling towers. Final report  

SciTech Connect

Drift from mechanical draft cooling towers was studied to establish a data base for use in drift deposition model validation. This objective was met by the simultaneous measurement of cooling tower source emission parameters, meteorological variables and drift deposition patterns during seven of eight test runs. Results from six of these test runs are presented and discussed. Source characterization measurements were made of cooling tower emission parameters such as updraft velocity and temperature profiles, liquid and mineral mass drift emission rates, and drift droplet size distributions. The meteorological measurements included wet- and dry-bulb temperature and wind speed and direction at various heights to provide information on the vertical structure of temperature, moisture and mass transport. Surface deposition measurements included both droplet and bulk mineral mass deposition rates. Substantial variation in drift emissions were noticed. Large day-to-day variations for a given cell and large cell-to-cell variations were observed. The problem of deriving a total droplet emission spectrum and rate from one or two towers is complicated and the modeler must decide on the amount of detail he needs to satisfactorily predict downwind deposition patterns. Meteorological conditions during the drift study were characterized by relatively high winds, warm temperatures and moderate humidities. The relatively high winds increased the uncertainty in the measured deposition patterns. In spite of the large (factor of 2 or 3) uncertainty in the measured deposition rates, preliminary calculations of drift deposition rates are in agreement with each other for test run 1. Although the present study did not meet all the requirements for complete validation of various drift models, it has contributed a unique set of data for that purpose.

Laulainen, N.S.; Webb, R.O.; Wilber, K.R.; Ulanski, S.L.

1979-09-01

325

Analysis of airborne Doppler lidar, Doppler radar and tall tower measurements of atmospheric flows in quiescent and stormy weather  

NASA Technical Reports Server (NTRS)

The first experiment to combine airborne Doppler Lidar and ground-based dual Doppler Radar measurements of wind to detail the lower tropospheric flows in quiescent and stormy weather was conducted in central Oklahoma during four days in June-July 1981. Data from these unique remote sensing instruments, coupled with data from conventional in-situ facilities, i.e., 500-m meteorological tower, rawinsonde, and surface based sensors, were analyzed to enhance understanding of wind, waves and turbulence. The purposes of the study were to: (1) compare winds mapped by ground-based dual Doppler radars, airborne Doppler lidar, and anemometers on a tower; (2) compare measured atmospheric boundary layer flow with flows predicted by theoretical models; (3) investigate the kinematic structure of air mass boundaries that precede the development of severe storms; and (4) study the kinematic structure of thunderstorm phenomena (downdrafts, gust fronts, etc.) that produce wind shear and turbulence hazardous to aircraft operations. The report consists of three parts: Part 1, Intercomparison of Wind Data from Airborne Lidar, Ground-Based Radars and Instrumented 444 m Tower; Part 2, The Structure of the Convective Atmospheric Boundary Layer as Revealed by Lidar and Doppler Radars; and Part 3, Doppler Lidar Observations in Thunderstorm Environments.

Bluestein, H. B.; Doviak, R. J.; Eilts, M. D.; Mccaul, E. W.; Rabin, R.; Sundara-Rajan, A.; Zrnic, D. S.

1986-01-01

326

Doppler Radar Wind Profiles Iwan Holleman  

E-print Network

). The potential impact of a network of boundary layer wind profilers and sodars for mesoscale wind analysisDoppler Radar Wind Profiles Iwan Holleman Scientific Report, KNMI WR-2003-02, 2003 #12;2 #12 Strategy 18 3 Methods for Wind Profile Retrieval 25 3.1 Radial Velocity from Local Wind Model 25 3

Stoffelen, Ad

327

Socioeconomic Impacts of the Langdon Wind Energy Center  

Microsoft Academic Search

The Langdon Wind Energy Center is the largest wind energy facility to be developed in North Dakota to date and consists of 106 turbines with a generating capacity of 1.5 MW each, mounted on towers 262 feet tall. The project is owned by FPL Energy and Ottertail Power Company; FPL Energy was the project developer. Construction of the facility began

F. Larry Leistritz; Randal C. Coon

2008-01-01

328

Economic assessment of small-scale electricity generation from wind  

E-print Network

10 kW wind turbine on a 30m tower was installed and five different scenarios were calculated for both locations. Wind speeds for both locations were collected and analyzed to find the closest fitting distribution to incorporate the appropriate risk...

McAllister, Kristen Dawn

2007-09-17

329

System management of a wind-energy converter  

Microsoft Academic Search

Wind energy converters are commonly used in converting wind energy into useful mechanical and electrical energies. But the problems of smooth start, tower effect and oscillations caused by aerodynamic forces acting on the rotor cause fluctuations in its power output. A system management was designed to reduce these effects. It consists of a microcontroller. This was verified with the help

Charles Lemogo Kana; Manoharan Thamodharan; Albrecht Wolf

2001-01-01

330

The economic optimisation of horizontal axis wind turbine design  

Microsoft Academic Search

A method for determining the optimum design parameters for horizontal axis wind turbines was developed and tested. These design parameters were the rotor diameter, rated power and tower height. The optimum values were found to be dependent on site wind regime. The results of the study indicated that it was, however, only the optimisation of the relative combination of rotor

G. R. Collecutt; R. G. J. Flay

1996-01-01

331

The 100 kW experimental wind turbine generator project  

NASA Technical Reports Server (NTRS)

The Energy Research and Development Administration and the NASA Lewis Research Center engaged jointly in a Wind Energy Program which included the design and erection of a 100 kW wind turbine generator. This test machine consists of a rotor turbine, transmission, shaft, alternator, and tower. The rotor, measuring 125 feet in diameter and consisting of two variable pitch blades, operates at 40 rpm and generates 100 kW of electrical power at a wind velocity of 18 mph. The entire assembly is placed on top of a tower 100 feet above ground level. The machine was scheduled to be ready for operation in August, 1975.

Puthoff, R. L.; Sirocky, P.

1975-01-01

332

Influence of Wind Turbulence on Yaw-control Gears in Wind Turbine  

NASA Astrophysics Data System (ADS)

This paper describes an influence of wind turbulence on yaw-control gears of nacelle in a wind power station. This site is located in Tappi cape of Aomori prefecture where is characterized by a big wind turbulence due to the western strong wind and a steep slope of the cape. In this paper two adjacent wind towers are dealt with among eleven ones. To clarify an influence of the wind turbulence on the leeward wind power generator. The measurement results showed that the turbulence and the standard deviation exceeded IEC Wind Turbine Standards frequently. Accordingly the torque applied to the yaw control gears vibrated with short time period and its magnitude was frequently larger than 4.8 ton-m (47kN-m) regarded as the metal fatigue limit. By the method where the output of the wind turbine generator is controlled, the magnitude of the vibrating torque can be reduced under the limit of the material fatigue.

Suzuki, Kazuo; Hoshino, Naoki; Inomata, Noboru; Kimura, Hiroshi; Fujiwara, Tamiya

333

Cooling tower water conditioning study. [using ozone  

NASA Technical Reports Server (NTRS)

Successful elimination of cooling tower treatment chemicals was demonstrated. Three towers functioned for long periods of time with ozone as the only treatment for the water. The water in the systems was reused as much as 30 times (cycles of concentration) without deleterious effects to the heat exchangers. Actual system blow-down was eliminated and the only makeup water added was that required to replace the evaporation and mist entrainment losses. Minimum water savings alone are approximately 75.1 1/kg/year. Cost estimates indicate that a savings of 55 percent was obtained on the systems using ozone. A major problem experienced in the use of ozone for cooling tower applications was the difficulty of accurate concentration measurements. The ability to control the operational characteristics relies on easily and accurately determined concentration levels. Present methods of detection are subject to inaccuracies because of interfering materials and the rapid destruction of the ozone.

Humphrey, M. F.; French, K. R.

1979-01-01

334

The measurement of the ground wind structure at Wallops Island  

NASA Technical Reports Server (NTRS)

The mean and turbulence characteristics of the surface wind measured near the Atlantic coast were measured. The experimental data were acquired from a 76 meter tall instrumented micrometeorological tower. Mean wind and turbulence measurements were made with two types of instrumentation consisting of cup vane and temperature probes, primarily used for mean profile measurements of velocity and temperature respectively. The second system, a hot film and thermocouple system, was used for measurement of turbulence variances and covariances and spectra. The cup vane system was used to acquire data from all wind directions, while the hot film system was primarily used for turbulence measurements from the two prevailing wind directions, south and northwest. The micrometeorological tower is a self standing nonguyed tower with five working platforms at 15.2m (50 ft.) intervals, with cup vane and aspirated temperature probes mounted at each platform.

Tielman, H. W.

1981-01-01

335

Engineering photochemical smog through convection towers  

SciTech Connect

Reverse convection towers have attracted attention as a medium for cleansing modern cities. Evaporation of an aqueous mist injected at the tower opening could generate electrical power by creating descent, and simultaneously scavenge unsightly and unhealthful particulates. The study offered here assesses the influence to tower water droplets on the photochemical component of Los Angeles type smog. The primary radical chain initiator OH is likely removed into aqueous phases well within the residence time of air in the tower, and then reacts away rapidly. Organics do not dissolve, but nighttime hydrolysis of N{sub 2}O{sub 5} depletes the nitrogen oxides. A lack of HOx would slow hydrocarbon oxidation and so also ozone production. Lowering of NOx would also alter ozone production rates, but the direction is uncertain. SO{sub 2} is available in sufficient quantities in some urban areas to react with stable oxidants, and if seawater were the source of the mist, the high pH would lead to fast sulfur oxidation kinetics. With an accommodation coefficient of 10{sup {minus}3}, however, ozone may not enter the aqueous phase efficiently. Even if ozone is destroyed or its production suppressed, photochemical recovery times are on the order of hours, so that tower processing must be centered on a narrow midday time window. The cost of building the number of structures necessary for this brief turnover could be prohibitive. The increase in humidity accompanying mist evaporation could be controlled with condensers, but might otherwise counteract visibility enhancements by recreating aqueous aerosols. Quantification of the divergent forcings convection towers must exert upon the cityscape would call for coupled three dimensional modeling of transport, microphysics, and photochemistry. 112 refs.

Elliott, S.; Prueitt, M.L.; Bossert, J.E.; Mroz, E.J.; Krakowski, R.A.; Miller, R.L. [Los Alamos National Lab., NM (United States); Jacobson, M.Z.; Turco, R.P. [Los Alamos National Lab., NM (United States); [Univ. of California, Los Angeles, CA (United States). Atmospheric Sciences Dept.

1995-02-01

336

Wind resource characterization results to support the Sandia Wind Farm Feasibility Study : August 2008 through March 2009.  

SciTech Connect

Sandia National Laboratories Wind Technology Department is investigating the feasibility of using local wind resources to meet the requirements of Executive Order 13423 and DOE Order 430.2B. These Orders, along with the DOE TEAM initiative, identify the use of on-site renewable energy projects to meet specified renewable energy goals over the next 3 to 5 years. A temporary 30-meter meteorological tower was used to perform interim monitoring while the National Environmental Policy Act (NEPA) process for the larger Wind Feasibility Project ensued. This report presents the analysis of the data collected from the 30-meter meteorological tower.

Deola, Regina Anne

2010-01-01

337

Lessons learned from the Lena guyed tower  

SciTech Connect

The design, fabrication, and installation of the Lena guyed tower required the development of new offshore technology in several areas. Lessons learned from this experience include an understanding of the consequences of major design decisions and insight into the interactive behavior of the structural components. The guyed tower is now a proven deepwater production platform concept for the Gulf of Mexico and is also judged to be applicable for a wide range of water depths and deck loads in the North Sea and other areas of the world.

Finn, L.D.; Maus, L.D.

1984-10-01

338

Simplified modeling for wind turbine modal analysis using NASTRAN  

NASA Technical Reports Server (NTRS)

A detailed finite element model of the MOD-0 wind turbine tower was reduced to six beam elements (stick model). The method used to calculate the properties of the beam elements in the stick model was explained and the accuracy of the stick model in predicting natural frequencies and mode shapes was examined. Computer times were compared and several applications where the stick model was used are described. From results obtained from the MOD-0 tower it is concluded that a tower of this type can be modeled as a simple cantilever beam for modal analysis. However, this model should be limited to tower torsional modes and tower bending modes where the mode shape resembles a cantilever beam first bending mode shape.

Sullivan, T. L.

1978-01-01

339

Forecasting Cool Season Daily Peak Winds at Kennedy Space Center and Cape Canaveral Air Force Station  

NASA Technical Reports Server (NTRS)

The expected peak wind speed for the day is an important element in the daily 24-Hour and Weekly Planning Forecasts issued by the 45th Weather Squadron (45 WS) for planning operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The morning outlook for peak speeds also begins the warning decision process for gusts ^ 35 kt, ^ 50 kt, and ^ 60 kt from the surface to 300 ft. The 45 WS forecasters have indicated that peak wind speeds are a challenging parameter to forecast during the cool season (October-April). The 45 WS requested that the Applied Meteorology Unit (AMU) develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. The tool must only use data available by 1200 UTC to support the issue time of the Planning Forecasts. Based on observations from the KSC/CCAFS wind tower network, surface observations from the Shuttle Landing Facility (SLF), and CCAFS upper-air soundings from the cool season months of October 2002 to February 2007, the AMU created multiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence, the temperature inversion depth, strength, and wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft. Six synoptic patterns were identified: 1) surface high near or over FL, 2) surface high north or east of FL, 3) surface high south or west of FL, 4) surface front approaching FL, 5) surface front across central FL, and 6) surface front across south FL. The following six predictors were selected: 1) inversion depth, 2) inversion strength, 3) wind gust factor, 4) synoptic weather pattern, 5) occurrence of precipitation at the SLF, and 6) strongest wind in the lowest 3000 ft. The forecast tool was developed as a graphical user interface with Microsoft Excel to help the forecaster enter the variables, and run the appropriate regression equations. Based on the forecaster's input and regression equations, a forecast of the day's peak and average wind is generated and displayed. The application also outputs the probability that the peak wind speed will be ^ 35 kt, 50 kt, and 60 kt.

Barrett, Joe, III; Short, David; Roeder, William

2008-01-01

340

77 FR 3935 - National Environmental Policy Act Compliance for Proposed Tower Registrations; Effects of...  

Federal Register 2010, 2011, 2012, 2013, 2014

...characteristics (e.g., tower height, structure, lighting, or location...augmented to include the type of tower structure and the anticipated lighting...an existing tower or non-tower structure and the placement of the...

2012-01-26

341

6. View of south tower, facing south from Clover Island, ...  

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

6. View of south tower, facing south from Clover Island, across boat moorage channel. - Pasco-Kennewick Transmission Line, Columbia River Crossing Towers, Columbia Drive & Gum Street, Kennewick, Benton County, WA

342

3. View of north tower, facing north across the main ...  

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

3. View of north tower, facing north across the main channel of the Columbus River from Clover Island. - Pasco-Kennewick Transmission Line, Columbia River Crossing Towers, Columbia Drive & Gum Street, Kennewick, Benton County, WA

343

4. View of center tower at Clover Island, facing northeast. ...  

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

4. View of center tower at Clover Island, facing northeast. Pasco-Kennewick automobile bridge in background, lower right. - Pasco-Kennewick Transmission Line, Columbia River Crossing Towers, Columbia Drive & Gum Street, Kennewick, Benton County, WA

344

1. View of north tower, facing northwest from dike on ...  

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

1. View of north tower, facing northwest from dike on north bank of the Columbia River. - Pasco-Kennewick Transmission Line, Columbia River Crossing Towers, Columbia Drive & Gum Street, Kennewick, Benton County, WA

345

47 CFR 5.109 - Antenna and tower requirements.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Antenna and tower requirements. 5.109...Operating Requirements § 5.109 Antenna and tower requirements. (a) Applicants with fixed stations that use antennas that exceed 6 meters in...

2012-10-01

346

47 CFR 5.109 - Antenna and tower requirements.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Antenna and tower requirements. 5.109...Operating Requirements § 5.109 Antenna and tower requirements. (a) Applicants with fixed stations that use antennas that exceed 6 meters in...

2011-10-01

347

2. Detail of tower foundation with lightning transfer wire, southeast ...  

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

2. Detail of tower foundation with lightning transfer wire, southeast corner - Cold Mountain Fire Lookout Station, Lookout Tower, Krassel District, Frank Church River of No Return Wilderness, Dixie, Idaho County, ID

348

View of EPA Farm metal weather tower, facing east, showing ...  

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

View of EPA Farm metal weather tower, facing east, showing thirty-acre irrigated field - Nevada Test Site, Environmental Protection Agency Farm, Weather Tower, Area 15, Yucca Flat, 10-2 Road near Circle Road, Mercury, Nye County, NV

349

10. View west along carillon tower axis from base of ...  

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

10. View west along carillon tower axis from base of tower to gates in western estate wall at SR 141 - A. I. Du Pont Estate, Junction of State Route 141 & Rockland Road, Wilmington, New Castle County, DE

350

INTERIOR OF SA WETSIDE BUILDING. TOP OF CARBONATION TOWERS (SOLVAY ...  

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

INTERIOR OF SA WETSIDE BUILDING. TOP OF CARBONATION TOWERS (SOLVAY TOWERS) PROBABLY SAME LEVEL AS NY-300-D-6 BUT OPPOSITE VIEW. - Solvay Process Company, SA Wetside Building, Between Willis & Milton Avenue, Solvay, Onondaga County, NY

351

VIEW FROM DIVE TOWER CONFERENCE ROOM FACING NORTH (FIRST FLIGHT ...  

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

VIEW FROM DIVE TOWER CONFERENCE ROOM FACING NORTH (FIRST FLIGHT OF STAIRS) - U.S. Naval Base, Pearl Harbor, Submarine Dive Tower, Intersection of Clark & Morton Streets, Pearl City, Honolulu County, HI

352

TOWER, WEST ELEVATION, SHOWING CONNECTION PIPES FOR TURNOUTS 22 (FOREGROUND) ...  

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

TOWER, WEST ELEVATION, SHOWING CONNECTION PIPES FOR TURNOUTS 22 (FOREGROUND) AND 24. NOTE ?LAZY JACK? TEMPERATURE COMPENSATOR IN FOREGROUND. - Baltimore & Ohio Railroad, Z Tower, State Route 46, Keyser, Mineral County, WV

353

Digital places : rethinking urban elements : the case of the tower  

E-print Network

Problem - How can we make working, living and all aspects of our life in the urban tower more palatable? How can we create environment at the urban tower scale. With technology as one of the biggest drivers of social and ...

Gichuhi, Christopher M. (Christopher Mwethera), 1976-

2004-01-01

354

2. Light tower and keeper's house, view southwest, north northeast ...  

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

2. Light tower and keeper's house, view southwest, north northeast side of tower, northeast and northwest sides of keeper's house - Wood Island Light Station, East end of Wood Island, at mouth of Soo River, Biddeford Pool, York County, ME

355

1. Keeper's house and light tower, view north northeast, southwest ...  

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

1. Keeper's house and light tower, view north northeast, southwest and southeast sides of house, northwest and southwest sides of tower - Wood Island Light Station, East end of Wood Island, at mouth of Soo River, Biddeford Pool, York County, ME

356

1. VIEW NORTHWEST, operations building, height finder radar tower, and ...  

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

1. VIEW NORTHWEST, operations building, height finder radar tower, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

357

FIELD INVESTIGATIONS OF MECHANICAL DRAFT COOLING TOWER PLUMES  

EPA Science Inventory

Tethered Kitoon (small blimp) sampling techniques were devised to measure the distribution of temperature and humidity in the invisible portion of power plant cooling tower plumes from both single cell and multiple cell cooling towers under several conditions. These measurements,...

358

29. Photocopy of 1921 photograph. Glass Negative Box IX, Tower ...  

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

29. Photocopy of 1921 photograph. Glass Negative Box IX, Tower Grove, Missouri Botanical Garden. ITALIAN GARDEN AND NEW PALM HOUSE (DEMOLISHED), LOOKING NORTHEAST - Missouri Botanical Garden, 2345 Tower Grove Avenue, Saint Louis, Independent City, MO

359

1. Keeper's house and light tower, view north, south and ...  

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

1. Keeper's house and light tower, view north, south and east sides of keeper's house, southwest and southeast sides of tower - Whitehead Light Station, Whitehead Island, East northeast of Tenants Harbor, Spruce Head, Knox County, ME

360

2. Light tower, keeper's house and shed, view south southwest, ...  

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

2. Light tower, keeper's house and shed, view south southwest, northwest and northeast sides of tower, east and north sides of keeper's house and shed - Whitehead Light Station, Whitehead Island, East northeast of Tenants Harbor, Spruce Head, Knox County, ME

361

50. NORTHERN VIEW OF NONEVAPORATIVE WASTE WATER TREATMENT COOLING TOWERS ...  

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

50. NORTHERN VIEW OF NON-EVAPORATIVE WASTE WATER TREATMENT COOLING TOWERS IN CENTER, AND EVAPORATIVE WASTE WATER COOLING TOWERS ON RIGHT. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

362

1. Keeper's house and light tower, view northwest, south and ...  

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

1. Keeper's house and light tower, view northwest, south and east sides of keeper's house, southwest and southeast sides of light tower - Curtis Island Light Station, Curtis Island, at entrance to Camden Harbor, Camden, Knox County, ME

363

Cell block one and southeast guard tower, looking from the ...  

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

Cell block one and southeast guard tower, looking from the central guard tower, facing southeast (note view also includes cell block ten (left) and cell block nine (right)) - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

364

3. View looking E from top of World Trade Tower ...  

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

3. View looking E from top of World Trade Tower with World Trade Tower parapet in foreground. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York, New York County, NY

365

27. STATIC TEST TOWER CLOSEUP VIEW OF CONTROL PANEL AT ...  

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

27. STATIC TEST TOWER CLOSE-UP VIEW OF CONTROL PANEL AT REAR OF TOWER UNDER SHED ROOF. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

366

View of the penitentiary complex and central guard tower, looking ...  

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

View of the penitentiary complex and central guard tower, looking from the front of the administration building tower, facing north - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

367

View of the southwest guard tower, cell blocks seven and ...  

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

View of the southwest guard tower, cell blocks seven and eight, administration building west tower, and Fairmount Avenue, looking from the administration building facing west - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

368

Update on the Purdue University 2-second Drop Tower  

NASA Astrophysics Data System (ADS)

A small drop tower of approximately one second drop duration was built in the School of Aero-nautics and Astronautics at Purdue University beginning in 1998 and operated until summer 2007. This inexpensive tower in an old airplane hanger, was built largely by Yongkang Chen, now a Research Professor at Portland State University in Oregon, USA. In about 7 years of operations, the tower generated sufficient science results for Chen's PhD thesis[1] (summarized in three AIAA Journal papers[2-4]), Fitzpatrick's MS thesis[5], two industry projects for since-canceled advanced rodent habitats for ISS, and one project for NASA Marshall. In addition to the science use, Purdue undergraduate students designed, built, and performed simpler fluids experiments for their own career advancement, including a novel investigation of the impact of imperfect repeatability of initial conditions on a zero-g fluids experiment. The tower was also used for outreach to school children. It is most satisfying that Chen's PhD research in this small tower, and subsequent discussions and interactions, helped Weislogel to propose the two Vane Gap tests in his highly successful Capillary Fluids Experiment (CFE) in the International Space Station in 2006 and 2007[6]. Chen as been involved in the remodeling of these two Vane Gap cylinders for subsequent re-launch to ISS for a second round of experiments expected in 2010 and 2011. In August 2007 the School of Aeronautics and Astronautics at Purdue University moved into the new Neil Armstrong Hall of Engineering and construction on a new 2-second drop tower began. A vertical shaft of nearly 23 meters was designed into the building. An approximately 80 m2 general-use fluids lab is at the top level, and a small access room of approximately 9 m2 is at the bottom. However, construction of the new $57M building created only the space for the science facility, not the science facility itself. The science facility is under construction and this paper presents an update on progress for the micro-gravity community. The most noticeable current activity is testing of the air-bag decelerator. The tower is one that will use a free-falling experiment inside of a drag shield to avoid most aerodynamic drag. The airbag is designed from experiences of others yet the small, triangular room in which the tower terminates imposes challenges. The airbag is approximately 1.5m diameter and 1.5m tall. Initial testing led to a desire to increase vent area, and just this week the bag has returned from the shop that was modifying it. On-board computer, battery packs, lighting, and cameras have been acquired. Thanks to Lockheed Martin, one camera is 500 frames per second with 1.3 million 12-bit gray scale pixels per frame. The Spincraft company donated steel hemisphere-cylinders to serve as the nose of the drag shield. Wind tunnel and CFD modeling of the drag shield has been performed by Purdue undergraduate aerospace students. Currently the drag shield structure and experiment package structure are being design and analyzed. The experiment volume is approximately a cylinder 0.45m diameter and 0.6m tall. Tower operation is intended to commence in fall 2010 with inert package drops at full mass and full height. Developing the operations procedures, especially operational safety, are the goals of this work. First science is then expected in the winter. References 1. Y. Chen, "A Study of Capillary Flow in a Vane-wall Gap in Zero Gravity," Ph.D. thesis, School of Aeronautics and Astronautics, Purdue University. August 2003. 2. Y. Chen and S. H. Collicott, "Investigation of the Symmetric Wetting of a Vane-Wall Gap in Propellant Tanks," AIAA Journal, 42, No. 2, pp. 305-314, February 2004. 3. Y. Chen, and S. H. Collicott, "Experimental Study on the Capillary Flow in a Vane-Wall Gap Geometry," AIAA Journal, 43, No. 11, pp. 2395-2403, November, 2005. 4. Y. Chen and S. H. Collicott, "Study of Wetting in an Asymmetrical Vane-Wall Gap in Propellant Tanks," AIAA Journal, 44, 4, pp. 859-867, April 2006. 5. S. L. F

Collicott, Steven

369

Influences of offshore environmental conditions on wind shear profile parameters in Nantucket Sound  

E-print Network

Influences of offshore environmental conditions on wind shear profile parameters in Nantucket Sound@ecs.umass.edu ABSTRACT Simultaneous wind resource and oceanographic data are available from an offshore monitoring tower how oceanographic data can be used to aid offshore wind resource assessment evaluations. This study

Massachusetts at Amherst, University of

370

LARGE SCALE DEPLOYMENT OF RENEWABLE ENERGY BY COMBINING WIND FARMS WITH SOLAR THERMAL POWER PLANTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The installation of megawatt-size wind turbines on 65 to 80 meter towers at Class 4 wind sites in Texas has resulted in the cheapest form of renewable energy ($0.04/kWh). However, wind farm output has a diurnal mismatch to the utility electrical loading. Combining solar thermal power plants with w...

371

Insulation coordination of a wind turbine and a power distribution line  

Microsoft Academic Search

The lightning damage is one of the most serious problems for wind turbine generator systems and distribution\\/transmission lines. Direct lightning strokes to a wind tower or a blade frequently cause damages in the wind turbine generator systems. Direct lightning strokes to a distribution line have been considered for lightning protection design. The lightning back-flow current is also an important factor

Shozo Sekioka; Jun Takami; Shigemitsu Okabe

2011-01-01

372

Combined effects of deterministic and random loads in wind turbine design  

Microsoft Academic Search

Deficiencies of modeling the deterministic loading on wind turbine blades as a cumulative sum of wind shear, mean wind, tower shadow, gravitational, and centrifugal forces are examined. It is analytically shown by application of the Palmgren-Miner rule that periodic loadings which coincide in cycle result in damage exceeding the sum of the individual stresses. The necessity of calculating the probability

A. Raab

1980-01-01

373

A feasibility study of wind turbine blade surface crack detection using an optical inspection method  

E-print Network

]. Although the design life of a wind turbine is often claimed to be 20 years, early failure can affectA feasibility study of wind turbine blade surface crack detection using an optical inspection technique was investigated to assess its ability to detect surface flaws on an on-tower wind turbine blade

McCalley, James D.

374

Performance characteristics of an induced draft, counterflow, spray cooling tower  

E-print Network

of the work. He wishes s1so to thanlc Hr. Paul Hoffmann, President of' Lilie-Hof~ Cooling Towers, Inc. , and. Mr. Fred Rabe, regional representative of the same organization, for permission to publish the information contained, in this report... ~ ~ 18 ~ ~ s Sl Experimental Tower. ~ nozzle Arrangements ~ ~. . . . . ~. . . ~ Page ~ ~ ~ 11 Tower characteristic, KaV/L, plotted against water rate, L, for three nozzle arrange- ment s ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ t ~ ~ ~ ~ ~ o ~ ~ ~ 16 Tower...

Jones, Charles Edward

1951-01-01

375

An analysis of the weather research and forecasting model for wind energy applications in Wyoming  

NASA Astrophysics Data System (ADS)

Determination of wind speeds at the hub height of wind turbines is an important focus of wind energy studies. Standard extrapolation methods are unable to accurately estimate 50-m winds from standard 10-m winds under stable conditions. Modeling of winds is an alternative. Daily numerical simulations from December 2011-November 2012 have been conducted using the Weather Research and Forecasting model (WRF) to evaluate its potential for determining wind speeds at hub height. Model simulations have been validated with data collected at the University of Wyoming Wind Tower (UWT). WRF was superior to operational models in predicting 10-m wind speeds at surface stations and at the UWT. Results from WRF also showed that biases are present; WRF tends to overestimate winds during low-wind events and underestimate winds during high-wind events. WRF has demonstrated skill in hub height wind forecasts for Wyoming that can be of use for wind farm planning and operation.

Siuta, David

376

Monitoring the dynamic of suspended sediment using tower-based water spectrum observing system in the Hangzhou Bay  

NASA Astrophysics Data System (ADS)

Dynamic variations of suspended sediment (TSM) in extremely turbid waters of Hangzhou Bay (HZB) have been studied using a tower-based high-frequency water-spectrum observing system. We developed a practical data processing method for the high-frequency water-spectrum observation. In addition, the method was validated by the ASD measurement, and the results showed that the tower-measured normalized water-leaving radiance was consistent with it measured by ASD, with the correlation coefficient greater than 0.90 and the mean relative error of 6.48%. Based on the tower-measured water spectrum, the TSM was retrieved further with high frequency, and the results showed that the TSM in the HZB had significant diurnal and seasonal variations. The diurnal dynamics might mainly be caused by tidal induced resuspension, yet the seasonal variations might be derived by winds largely.

Dai, Qian; Gong, Fang; Huang, Haiqing; He, Xianqiang; Chen, Jianyu; Zhu, Qiankun

2014-10-01

377

47 CFR 5.109 - Antenna and tower requirements.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Antenna and tower requirements. 5.109 Section...Requirements § 5.109 Antenna and tower requirements. (a...station that has an antenna structure required to be painted and...inspections and maintain the tower marking and lighting,...

2010-10-01

378

Snowfall observations from natural-draft cooling tower plumes  

Microsoft Academic Search

During the winter of 1975-1976, snowfall from the plumes of large natural-draft cooling towers of power plants has been observed. Snow accumulations up to 2.5 centimeters have been found on the ground at extended distances from the cooling towers, and visibility has been restricted to less than 1600 meters in the tower plume near ground level.

M. L. Kramer; D. E. Seymour; M. E. Smith; R. W. Reeves; T. T. Frankenberg

1976-01-01

379

8. VIEW OF THE EAST BASE CONNECTION OF ANTENNA TOWER ...  

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

8. VIEW OF THE EAST BASE CONNECTION OF ANTENNA TOWER S-111 FACING NORTHEAST. BUILDING 1 AND ANTENNA TOWER S-110 IN THE BACKGROUND. - U.S. Naval Base, Pearl Harbor, Lualualei Radio Transmitter, Edison & Tower Drives, Pearl City, Honolulu County, HI

380

2. VIEW SOUTHWEST, prime search radar tower, height finder radar ...  

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

2. VIEW SOUTHWEST, prime search radar tower, height finder radar towards, height finder radar towers, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

381

4. VIEW NORTHEAST, radar tower (unknown function), prime search radar ...  

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

4. VIEW NORTHEAST, radar tower (unknown function), prime search radar tower, emergency power building, and height finder radar tower - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

382

Multi-objective optimization of solar tower heliostat fields  

E-print Network

the com- putational time is reduced significantly, the presented implementation is sufficiently fast Introduction Solar tower plants generate electric power from sunlight by focusing concentrated solar radiation electricity. Fig. 1 Solar tower plant PS10, 11 MW in Andalusia, Spain. [Source: flickr] Solar tower plants

Ábrahám, Erika

383

3. View from former light tower to Cape Elizabeth Light ...  

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

3. View from former light tower to Cape Elizabeth Light Tower, view northeast, southwest side of Cape Elizabeth Tower - Cape Elizabeth Light Station, Near Two Lights State Park at end of Two Lights Road, off State Highway 77, Cape Elizabeth, Cumberland County, ME

384

View of second bank of circuit towers on Arizona side ...  

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

View of second bank of circuit towers on Arizona side of canyon. Left tower supports Circuit 10 and right tower supports Circuit 11, view north - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

385

Efficacy of Tower Medfly Eclosion Systems  

Microsoft Academic Search

A 16-repetition experiment was conducted to evaluate the performance of the “tower” system for eclosion of sterile medflies, Ceratitis capitata (Wiedemann). This system has now replaced the PARC system previously used in Florida S.I.T. programs. In addition to testing the efficacy of these eclosion systems, as compared to the PARC system, quality control was also monitored and evaluated. No significant

Mark Salvato; Tim Holler; John Worley; Joe Stewart

2004-01-01

386

Balsa Tower Walls Brave "Big Buster"  

ERIC Educational Resources Information Center

Like many technology teachers, the author, a technology education teacher at Arthur Hill High School in Saginaw, Michigan, tries to stretch his budget by "milking" each student activity for maximum benefit. In the technology department, they use balsa wood towers to teach the basics of structural engineering. To get the most from their materials,…

Granlund, George

2008-01-01

387

The Tower and Glass Marbles Problem  

ERIC Educational Resources Information Center

The Catseye Marble company tests the strength of its marbles by dropping them from various levels of their office tower, to find the highest floor from which a marble will not break. We find the smallest number of drops required and from which floor each drop should be made. We also find out how these answers change if a restriction is placed on…

Denman, Richard T.; Hailey, David; Rothenberg, Michael

2010-01-01

388

Remote Sensing Instrument for Tower Installation  

USGS Multimedia Gallery

USGS collaborator Jin Wu (University of Arizona) prepares a remote sensing instrument for installation near the top of a 213-foot (65-meter) tower at the Amazon forest study site near Santarém, Brazil. The sensor system is being used to improve understanding of how photosynthesis in tropical ...

389

Sensors Installed on Amazon Observation Tower  

USGS Multimedia Gallery

Sensors installed on this 213-foot (65-meter) tower  near Santarém, Brazil are used by USGS Geographer Dennis Dye and his U.S., Brazilian and Australian collaborators to improve understanding of how seasonal variations in climate affects photosynthesis and the uptake of atmospheric carbo...

390

Adjusting Remote Sensing System before Tower Installation  

USGS Multimedia Gallery

USGS collaborator Scott Saleska (University of Arizona) makes adjustments to a remote sensing system before installation near the top of a 213-foot (65-meter) tower at the Amazon forest study site near Santarém, Brazil.    Data from the system are being used by Saleska, USGS Ge...

391

How cooling towers affect process energy savings  

Microsoft Academic Search

In contrast to the utility industry, the chemical and petroleum refining industries have neglected the effect of the ambient air on total energy consumption. The cooling water circuit, including the cooling tower (CT), plays an important role in the total energy balance; therefore, it should be brought into the domain of the energy manager in the same way he has

W. V. L. Campagane; L. J. McDonough

1984-01-01

392

Ergonomics analysis on tower fans design  

Microsoft Academic Search

Based on the theory and methods of ergonomics, the human factors such as shape, button, information indicating, the functional arrangement, color and material of small household electrical appliances - Media FS60-6AR landing tower fans were deeply analysed and studied, the study explained that design of their own should be in accordance with the relevant requirements of ergonomics. In the finally,

Jiang Hong; Li Kailing; Zhao Yingxin; Xu Fengqin

2009-01-01

393

Top of the Tower Coffee Lounge Menu  

E-print Network

% Top of the Tower Coffee Lounge Menu Assorted cakes, pasties & scones from.90 Add coleslaw or cheese for only £0.65 Large £2.30 Plain omelette served with salad and coleslaw............................. £2.90 Cheese & tomato OR ham & tomato omelette from........................ £3.20 Add fries for only

Davidson, Fordyce A.

394

WET/DRY COOLING TOWER TEST MODULE  

EPA Science Inventory

The report gives results of an evaluation of the engineering performance of a single-cell wet/dry cooling tower (about 25 MW) in an 18-month field test at San Bernardino, CA. Test objectives included determination of the water conservation and operating characteristics, and verif...

395

Cooling Tower Considerations for Energy Optimizations  

E-print Network

generated by the fan should first be looked at In both counterflow or crossflow towers to determine that maximum flow is available through pitching fans up to within the motor plate amperage limitations and fan stall point calculations. If applicable, new...

Burger, R.

1986-01-01

396

Cooling Towers--Energy Conservation Strategies Preservative Spray Treatment Maintains Cooling Tower  

E-print Network

Several problems common to most industrial wood framed cooling towers can be easily controlled with annual preservative spray treatment applications to the plenum area framework and drift eliminators. It eliminates the expensive periodic repairs due...

Reidenback, R.

397

ETR COOLING TOWER. PUMP HOUSE (TRA645) IN SHADOW OF TOWER ...  

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

ETR COOLING TOWER. PUMP HOUSE (TRA-645) IN SHADOW OF TOWER ON LEFT. AT LEFT OF VIEW, HIGH-BAY BUILDING IS ETR. ONE STORY ATTACHMENT IS ETR ELECTRICAL BUILDING. STACK AT RIGHT IS ETR STACK; MTR STACK IS TOWARD LEFT. CAMERA FACING NORTHEAST. INL NEGATIVE NO. 56-3799. Jack L. Anderson, 11/26/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

398

Possibilities and limitations of wind energy utilisation  

NASA Astrophysics Data System (ADS)

The existing wind resource, the most favorable locations, applications, and designs of windpowered generators are reviewed, along with descriptions of current and historic wind turbines and lines of research. Coastal regions, plains, hill summits, and mountains with funneling regions are noted to have the highest annual wind averages, with energy densities exceeding the annual solar insolation at average wind speeds of 5-7.9 m/sec. Applications for utility-grade power production, for irrigation, for mechanical heat production, and for pumped storage in water towers or reservoirs are mentioned, as well as electrical power production in remote areas and for hydrogen production by electrolysis. Power coefficients are discussed, with attention given to the German Growian 3 MW machine. It is shown that the least economically sound wind turbines, the machines with outputs below 100 kW, can vie with diesel plant economics in a good wind regime if the wind turbine operates for 15 yr.

Feustel, J.

1981-10-01

399

Using Virtual Tall Tower [CO2] Data in Inverse Models to Reduce Uncertainty in Global and Regional Estimates of Carbon Flux  

NASA Astrophysics Data System (ADS)

Previous studies in optimization of carbon observing networks considered any global grid cell as eligible for selection as a measurement site. In reality, measurement of mean CO2 over highly variable terrestrial regions is very impractical and expensive. A global network of eddy covariance flux towers already exists where continuous measurements of CO2 are taken, as well as measurements of sensible heat (H), latent heat (LE), and net ecosystem exchange (NEE). If the CO2 measurements were calibrated, these surface layer values could be extrapolated to the mixed-layer using similarity theory providing a means to sample the continental mixed-layer for use in global inversions to further constrain the carbon budget. We show that with this method for estimating the mid-day continental boundary layer [CO2] from calibrated [CO2] and eddy covariance measurements at flux towers, a network of "virtual tall towers" can be readily implemented using existing infrastructure and minimal additional instrumentation. Using the TransCom3 experimental protocol, sites where high-frequency timeseries were saved from the forward runs of 12 transport models were used as eligible sites for possible global networks. The fluxes were optimized to fit the monthly mean of mid-day values by sub-sampling the global fields during the afternoon only, when this method works best. A genetic algorithm was used to determine which existing measurement sites should be grouped together in a network that can most reduce the root mean square uncertainty on estimates of carbon flux. The algorithm evolves the most "fit" population of flux tower sites by comparing and prioritizing them according to their performance in the inversions. A global and North American experiment were performed to determine which ten or five towers should be implemented first as virtual tall towers. In the global selection of ten towers, the algorithm selected four sites in North, Central, and South America in the strong flux areas of the tropics and eastern US. Two towers were selected in southern Europe, even though Europe has a dense network, to constrain the regions of North and South Africa. Two towers were selected in Thailand and two in Japan to constrain Temperate and Boreal Asia, respectively. In the North American experiment, the optimal network selected five sites located in North Carolina, Missouri, Illinois, Tennessee, and Maryland. Overall, the strategies of bracketing the main flux areas and making observations through a gradient of fluxes didn't work well in the TransCom3 inversions. The best virtual tall tower networks emphasized placement of measuring sites in and just downwind of strong fluxes.

Skidmore, J.; Denning, A.; Gurney, K. R.; Davis, K. J.; Rayner, P. J.

2003-12-01

400

Observations of wind turbine wakes and surface roughness effects on wind flow variability  

SciTech Connect

Wind data collected at nine meteorological towers at the Goodnoe Hills MOD-2 wind turbine site were analyzed to characterize the wind flow over the site both in the absence and presence of wind turbine wakes. Free-flow characteristics examined were the variability of wind speed and turbulence intensity across the site as a function of wind direction and surface roughness. The nine towers' data revealed that scattered areas of trees upwind of the site caused pronounced variations in the wind flow over the site. Wind turbine wake characteristics analyzed included the average velocity deficits, wake turbulence, wake width, wake trajectory, vertical profile of the wake, and the stratification of wake properties as a function of the ambient wind speed and turbulence intensity. The wind turbine rotor disk spanned a height of 15 m to 107 m. The nine towers' data permitted a detailed analysis of the wake behavior at a height of 32 m at various downwind distances from 2 to 10 rotor diameters (D). The relationship between velocity deficit and downwind distance was surprisingly linear, with average maximum deficits ranging from 34% at 2 D to 7% at 10 D. Largest deficits were at low wind speeds and low turbulence intensities. Average wake widths were 2.8 D at a downwind distance of 10 D. Implications for turbine spacing are that, for a wind farm with a 10-D row separation, array losses would be significantly greater for a 2-D than a 3-D spacing because of incremental effects caused by overlapping wakes. Other interesting wake properties observed were the wake turbulence, the vertical variation of deficits, and the trajectory of the wake.

Elliott, D.L.; Barnard, J.C. (Pacific Northwest Lab., Richland, WA (USA))

1990-01-01

401

Power coefficient of tornado-type wind turbines  

SciTech Connect

In a tornado-type wind turbine the wind collecting tower is equipped with adjustable vanes that can be opened on the windward side and closed on the leeward side. The wind enters the tower tangentially through these open vanes and exits from the top. As a result, a vortex is formed inside the tower. A vertical axis turbine which is located underneath the tower floor admits air vertically and exhausts it into the vortex core. The pressure drop in the vortex core can be high, depending upon the vortex concentration, thus enhancing manyfold the total pressure drop across the turbine. The power coefficient C /SUB p/ of this system depends mainly on how low a pressure can be created in the vortex core. A maximum C /SUB p/ of about 2.5 was obtained by Yen for a spiral shaped tower. This is about 6.25 times the C /SUB p/ of conventional windmills. Analytical studies have been carried out by several investigators to study the C /SUB p/ of this vortex machine. Loth considered the conservation of angular momentum and obtained a C /SUB p/ based on the tower frontal area, which is not impressive.

Rangwalla, A.A.; Hsu, C.T.

1983-11-01

402

Characterizing Inflow Conditions Across the Rotor Disk of a Utility-Scale Wind Turbine (Poster)  

SciTech Connect

Multi-megawatt utility-scale wind turbines operate in a turbulent, thermally-driven atmosphere where wind speed and air temperature vary with height. Turbines convert the wind's momentum into electrical power, and so changes in the atmosphere across the rotor disk influence the power produced by the turbine. To characterize the inflow into utility scale turbines at the National Wind Technology Center (NWTC) near Boulder, Colorado, NREL recently built two 135-meter inflow monitoring towers. This poster introduces the towers and the measurements that are made, showing some of the data obtained in the first few months of operation in 2011.

Clifton, A.; Lundquist, J. K.; Kelley, N.; Scott, G.; Jager, D.; Schreck, S.

2012-01-01

403

Characterising the effect of a variety of surface roughness on boundary layer wind and dynamics within the scanning Doppler lidar network in Finland  

NASA Astrophysics Data System (ADS)

Aerosol particle and trace gas atmospheric content is controlled by natural and anthropological emissions. However, further dispersion in the atmosphere is driven by wind and dynamic mixing. Atmospheric surface and boundary layer dynamics have direct and indirect effects on weather, air quality and processes affecting climate (e.g. gas exchange between ecosystem and atmosphere). In addition to the amount of solar energy and prevailing meteorological condition, the surface topography has a strong influence on the close to surface wind field and turbulence, particularly in urban areas (e.g. Barlow and Coceal, 2009). In order to characterise the effect of forest, urban and coastal surfaces on boundary layer wind and mixing, we have utilised the Finnish Doppler lidar network (Hirsikko et al., 2013). The network consists of five 1.5 ?m Doppler lidars (HALO Photonics, Pearson et al., 2009), of which four are capable of full hemispheric scanning and are located at Helsinki (60.12°N, 25.58°E, 45 m asl.), Utö island (59.47°N, 21.23°E, 8 m asl.), SMEAR II at Hyytiälä (61.50°N, 24.17°E, 181 m asl.) and Kuopio (62.44°N, 27.32°E, 190 m asl.). The fifth lidar at Sodankylä (67.37°N, 26.63°E, 171 m asl.) is a new model designed for the Arctic environment with no external moving parts, but still retains limited scan capability. Investigation of boundary layer wind and mixing condition can now be extended beyond vertical profiles of horizontal wind, and dissipation rate of turbulent kinetic energy (O'Connor et al., 2010) throughout the boundary layer. We have applied custom designed scanning routines for 3D-observation of the wind fields and simultaneous aerosol particle distribution continuously for over one year at Helsinki and Utö, and began similar scanning routines at Kuopio and Hyytiälä in spring 2013. In this long term project, our aims are to 1) characterise the effect of the land-sea interface and the urban environment on the wind and its turbulent nature near the surface (< 200 m above the ground) observed at our four measurement sites, 2) characterise aerosol particle spatial and temporal distribution, and 3) deploy obtained results in air quality monitoring purpose and weather models. Here, we focus on wind field characterisation. The effect of sea, land and certain buildings were clear and evident in our wind data. The results compare favourably with in-situ point observations available indicating the applicability of the 3D-measurement routines and subsequent data analysis. Acknowledgements This research was supported by funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant 262254, and by the Maj and Tor Nessling foundation (Dispersion of air pollution in the boundary layer - new approach with scanning Doppler lidars). References Barlow J. and Coceal, O.: A review of urban roughness sublayer turbulence, Met Office Tech. Rep., Exeter, p. 68, 2009. Hirsikko, A., et al.: Observing aerosol particles, clouds and boundary layer wind: a new remote sensing network in Finland, in preparation for Atmos. Meas. Tech., 2013. O'Connor, E.J., Illingworth, A.J., Brooks, I.M., Westbrook, C.D., Hogan, R.J., Davies, F. and Brooks, B.J.: A Method for Estimating the Turbulent Kinetic Energy Dissipation Rate from a Vertically Pointing Doppler Lidar, and Independent Evaluation from Balloon-Borne In Situ Measurements, J. Atmos. Ocean. Technol., 27, 1652-1664, 2010. Pearson, G., Davies, F., and Collier, C.: An Analysis of the Performance of the UFAM Pulsed Doppler Lidar for Observing the Boundary Layer, J. Atmos. Ocean. Tech., 26, 240-250, 2009.

Hirsikko, Anne; O'Connor, Ewan J.; Wood, Curtis R.; Vakkari, Ville

2013-04-01

404

A Study of Lightning Current Distribution at a Wind Turbine Foot  

NASA Astrophysics Data System (ADS)

A Rogowski coil, used for measuring lightning current through a wind turbine generator system, is generally set up at the foot of a tower. In most wind turbines, there is an entrance at the foot of the tower, which leads to a flight of stairs or a ladder. When lightning strikes the wind turbine, the lightning current flows to the ground through the blades, nacelle, and tower. The current is shunted to the tower and the stairs/ladder at the foot of the tower, from where it may flow into the foundation and the earth. A Rogowski coil is usually set up at only the foot of a tower. The lightning current shunted to the stairs/ladder cannot be measured using the Rogowski. The installation position of the Rogowski coil depends on the construction of the stairs/ladder. In this study, the lightning current distribution at the foot of a tower is calculated using the FDTD (Finite Difference Time Domain) method, which is one of methods used for numerical analyses of electromagnetic fields. We also studied the effect that the setup of the stairs/ladder and the resistivity of the ground have on the lightning current distribution. The results of the current distribution are very important for predicting the total current that flows through an existing wind turbine generator system.

Yamamoto, Kazuo; Ueda, Naoya; Ametani, Akihiro; Natsuno, Daisuke

405

Wind Turbines Adaptation to the Variability of the Wind Field  

NASA Astrophysics Data System (ADS)

WIND TURBINES ADAPTATION TO THE VARIABILITY OF THE WIND FIELD The subject of our scientific research is wind power turbines (WPT) with the horizontal axis which were now common in the world. Efficient wind turbines work is largely determined by non-stationarity of the wind field, expressed in its gustiness, the presence of vertical and horizontal shifts of wind speed and direction. At critical values of the wind parameters WPT has aerodynamic and mechanical overload, leading to breakdowns, premature wear and reduce the life of the wind turbine. To prevent accidents at the peak values of wind speed it is used the regulatory system of windwheels. WPT control systems provide a process orientation of the wind turbine rotor axis in the line of the mean wind. Wind turbines are also equipped with braking device used to protect against breakdowns when a significant increase in the wind. In general, all these methods of regulation are not always effective. Thus, in practice there may be situations when the wind speed is many times greater than the stated limit. For example, if there are microbursts in the atmospheric boundary layer, low-level wind shears caused by its gust front, storms, etc. It is required for a wind power turbine adaptation to intensive short-term wind impulses and considerable vertical wind shifts that the data about them shall be obtained ahead of time. To do this it is necessary to have the information on the real structure of the wind field in the area of the blade sweep for the minimum range against the wind that is determined by the mean speed and the system action time. The implementation of acoustic and laser traditional wind sounding systems is limited by ambient acoustic noise, by heavy rain, snowfall and by fog. There are free of these disadvantages the inclined radioacoustic sounding (IRASS) technique which works for a system of remote detection and control of wind gusts. IRASS technique is realized as low-potential Doppler pulse radar including combined RF-acoustic antenna installed coaxially with the gondola of the wind power turbine. The work of the technique is synchronized with rotation of blades to eliminate their shielding action. Dangerous in terms of dynamic strength is the wind load pulse, the rise time which is comparable with the period of the natural frequency of the wind turbine elements (blade, tower, rotor, etc.). The amplitude decay of resonant vibrations at critical values of the speed of rotation can be realized through the use of mechanical elastic supports with nonlinear artificial dampers. They have a high coefficient of resistance, but may cause self-excited oscillations. We propose the way to deal with raised vibration of wind turbine elements at the expense of short-term increase of damping in the range of critical rotary axis speeds or during impulsive effects of wind loadings (wind gusts). This is possible through the use of non-linear electromagnetic dampers or active magnetic bearings. Their feature is the possibility of varying the mechanical stiffness and damping properties by changing the electrical parameters of electromagnets. The controlling of these parameters is carried out by the control system (CS) with the information feedback on the spatial-temporal structure of the wind field obtained from IRASS. In the composition of the CS can also be included the rotational speed sensor of the WPT rotor. This approach to the adaptation of wind turbines will allow to reduce vibration and to perform early compensation of the load on their components, which arise under the wind gusts. In addition, corrections about the wind field obtained with IRASS, would increase the mean power of WPT.

Ulianov, Yuriy; Martynenko, Gennadii; Misaylov, Vitaliy; Soliannikova, Iuliia

2010-05-01

406

Effects of structure flexibility on horizontal axis wind turbine performances  

NASA Astrophysics Data System (ADS)

This work illustrates the effects of flexibility of rotor blades and turbine tower on the performances of an horizontal axis wind turbine (HAWT) designed by our ADAG research group, by means of several example applied on a recent project for a active pitch controlled upwind 60 kW HAWT. The influence of structural flexibility for blade only, tower only and blade coupled with tower configuration is investigated using an aero-elastic computer-aided engineering (CAE) tool for horizontal axis wind turbines named FAST developed at National Renewable Energy Laboratory (NREL) of USA. For unsteady inflow conditions in front of the isolated HAWT the performances in rigid and flexible operation mode are computed and compared in order to illustrate the limitation included within a classical rigid body approach to wind turbine simulation.

Coiro, D. P.; Daniele, E.; Scherillo, F.

2013-10-01

407

Aerodynamic interference between two Darrieus wind turbines  

SciTech Connect

The effect of aerodynamic interference on the performance of two curved bladed Darrieus-type vertical axis wind turbines has been calculated using a vortex/lifting line aerodynamic model. The turbines have a tower-to-tower separation distance of 1.5 turbine diameters, with the line of turbine centers varying with respect to the ambient wind direction. The effects of freestream turbulence were neglected. For the cases examined, the calculations showed that the downwind turbine power decrement (1) was significant only when the line of turbine centers was coincident with the ambient wind direction, (2) increased with increasing tipspeed ratio, and (3) is due more to induced flow angularities downstream than to speed deficits near the downstream turbine.

Schatzle, P.R.; Klimas, P.C.; Spahr, H.R.

1981-04-01

408

Factors Influencing Wind Energy Curtailment  

Microsoft Academic Search

Nonphysically firm wind generation connections (i.e., those to which curtailment can apply) may be necessary for signifi- cant wind integration to congested transmission networks. A study of factors influencing this associated wind energy curtailment is, therefore,oftimelyimportance.Inthispaper,thewindcurtailment estimation effects of natural inter-yearly wind profile variability, systemdemand-profile\\/fuel-priceparameteruncertainty,andmin- imum system inertial constraints are studied in detail. Results in- dicate that curtailment estimation error

Daniel J. Burke; Mark J. O'Malley

2011-01-01

409

Wet/dry cooling tower and method  

DOEpatents

A wet/dry cooling tower wherein a liquid to-be-cooled is flowed along channels of a corrugated open surface or the like, which surface is swept by cooling air. The amount of the surface covered by the liquid is kept small compared to the dry part thereof so that said dry part acts as a fin for the wet part for heat dissipation.

Glicksman, Leon R. (Lynnfield, MA); Rohsenow, Warren R. (Waban, MA)

1981-01-01

410

Wind Energy for Electric Power: An REPP Issue Brief  

NSDL National Science Digital Library

This 29-page paper "focuses on utility-scale electricity generation from wind and provides an overview of the history, technologies, economics, environmental impacts, regulations and policies related to this use of wind power." Published by the Renewable Energy Policy Project and updated in November 2003, the document outlines recent trends in turbine technology that have made wind energy more reliable and cost effective. Design issues for towers and turbines are briefly touched upon. The paper also addresses environmental concerns. Finally, the benefits of existing wind farms and future wind energy developments are considered.

Reeves, Ari.

2003-01-01

411

Legionella in Puerto Rico cooling towers  

SciTech Connect

Water samples from air conditioning cooling towers receiving different treatment protocols on five large municipal buildings in San Juan, Puerto Rico were assayed for various species and serogroups of Legionella spp. using direct immunofluorescence. Several water quality parameters were also measured with each sample. Guinea pigs were inoculated with water samples to confirm pathogenicity and recover viable organisms. Legionella pneumophila (1-6), L. bozemanii, L. micdadei, L. dumoffii, and L. gormanii were observed in at least one of the cooling towers. L. pneumophila was the most abundant species, reaching 10{sup 5} cells/ml, within the range that is considered potentially pathogenic to humans. A significantly higher density of L. pneumophila was observed in the cooling tower water that was not being treated with biocides. Percent respiration (INT) and total cell activity (AODC), were inversely correlated with bacterial density. This study demonstrates that Legionella spp. are present in tropical air-conditioning cooling systems, and without continuous biocide treatment may reach densities that present a health risk.

Negron-Alviro, A.; Perez-Suarez, I.; Hazen, T.C. [Univ. of Puerto Rico, Rio Piedras (Puerto Rico)

1988-12-31

412

Legionella spp. in Puerto Rico cooling towers.  

PubMed Central

Water samples from air conditioning cooling towers receiving different treatment protocols on five large municipal buildings in San Juan, P.R., were assayed for various Legionella spp. and serogroups by using direct immunofluorescence. Several water quality parameters were also measured for each sample. Guinea pigs were inoculated with water samples to confirm pathogenicity and recover viable organisms. Legionella pneumophila serogroups 1 to 6, L. bozemanii, L. micdadei, L. dumoffii, and L. gormanii were observed in at least one of the cooling towers. L. pneumophila was the most abundant species; its density reached 10(5) cells per ml, which is within the range that is considered potentially pathogenic to humans. A significantly higher density of L. pneumophila was observed in the cooling tower water that was not being treated with biocides. Percent respiration (INT) and total cell activity (acridine orange direct count) were inversely correlated with bacterial density. This study demonstrates that Legionella spp. are present in tropical air-conditioning cooling systems and that, without continuous biocide treatment, they may reach densities that present a health risk. PMID:3202625

Negrón-Alvíra, A; Pérez-Suarez, I; Hazen, T C

1988-01-01

413

Water-conserving cooling tower treatment  

SciTech Connect

Water conservation in cooling towers and evaporative coolers can finally become a reality. Also, fouled closed hot and chilled water systems can be restored to near original efficiency using the same technology. The barrier limiting the traditional water treatment industry from serious involvement in water conservation is the lack of a really good chemical to control scale. Poor scale inhibitors are the reason for a heavy bleed. Minerals concentrated by evaporation is wasted to the sewer while low solids make-up water fills the tower. Water conservation is important because of the increasing usable water shortage, the cost to add infrastructure to deliver increasing amounts of water to accommodate growth and the limitations imposed on disposal to the sewer. Now, due to innovations in chemical treatment, users of cooling towers and evaporative coolers can conserve water. In this presentation the author assumes the audience has some knowledge of traditional water treatment. Except for a few general references to establish common understanding, the author confines his remarks to discussing an advanced technology developed by DIAS, Inc., and the economics of its use.

Mathie, A.J. [A.J. Mathie Company, Roy, UT (United States)

1996-12-31

414

Aspects of cooling tower biocides and protozoa  

SciTech Connect

Previous work has shown that certain cooling tower amoebae and ciliated protozoa are resistant to several cooling tower biocides, even at the manufacturer`s recommended dosages. For the present study, an Acunthumoeba species was isolated from a cooling tower in Australia. Suspensions of the trophozoites (feeding stages) were exposed to isothiazolones. Cysts were tested separately. The minimum lethal concentration (MLC) for trophozoites was between 31-62 ppm of the biocide product, which is slightly less than the MLC for an amoebae species from the United States; and cyst forms were twofold more resistant than those of the US species, with a MLC of 62,500 ppm. A ciliate and an amoeba species were also exposed to bromochlorodimethylhydantoin. The MLC for the ciliate species was 1 ppm of the biocide product, and the MLC was 30--40 ppm for the amoeba trophozoites. Since amoebae can expel vesicles containing live Legionella, experiments were conducted to determine whether exposure of Acunthamoebu polyphugu to biocides influenced release of such potentially infectious particles. Vesicle release was not inhibited by any of the three biocides: quaternary ammonium compounds (QACs), isothiazolones, and a thiocarbamate compound. These results suggest that amoebae from various sources are resistant to recommended levels of biocides, and the amoebae may continue to release potentially infectious vesicles in the presence of biocides.

Berk, S.G.; Ashburn, R.J.; Ting, R.S. [Tennessee Technological Univ., Cookeville, TN (United States). Center for the Management, Utilization and Protection of Water Resources

1998-12-31

415

Harnessing Wind  

NSDL National Science Digital Library

Students are introduced to the ways that engineers study and harness the wind. They learn about the different kinds of winds and how to measure wind direction. In addition, they learn how air pressure creates winds and how engineers design and test wind turbines to harness renewable wind energy.

Integrated Teaching And Learning Program

416

Investigations of the Tornado Wind-Energy System. Final report, September 1978-April 1980  

SciTech Connect

Tornado-type Wind Energy Systems (TWES) use the core of a vortex in a hollow tower to provide a low pressure exhaust reservoir for a wind turbine. Wind tunnel data are presented, and previous and planned test programs are described, including the evolution of tower design from the spiral-cross-sectional design through the passive omnidirectional design to the fixed-vane omnidirectional design. A larger model with a 15-ft height tower and a 30-in. diameter turbine is described, including details on design, configuration, and instrumentation, plus details on the test-rig for testing the 30-in. turbine under a staight-flow environment. Results on turbine efficiency, tip-speed-ratio, and turbine disk loading coefficient are presented and discussed. A new cost analysis is presented that makes cost estimates for large TWES systems using the measured performance of small models without scaling laws, plus the tower cost estimates deduced from the simple structural anlaysis. (LEW)

Yen, J.T.

1980-05-01

417

Accurate aircraft wind measurements using the global positioning system (GPS)  

SciTech Connect

High accuracy measurements of the spatial distribution of wind speed are required in the study of turbulent exchange between the atmosphere and the earth. The use of a differential global positioning system (GPS) to determine the sensor velocity vector component of wind speed is discussed in this paper. The results of noise and rocking testing are summarized, and fluxes obtained from the GPS-based methods are compared to those measured from systems on towers and airplanes. The GPS-based methods provided usable measurements that compared well with tower and aircraft data at a significantly lower cost. 21 refs., 1 fig., 2 tabs.

Dobosy, R.J.; Crawford, T.L., McMillen, R.T., Dumas, E.J. [Atmospheric Turbulence and Diffusion Div., Oak Ridge, TN (United States)

1996-11-01

418

Dynamic blade loading in the ERDA/NASA 100 kW and 200 kW wind turbines  

NASA Technical Reports Server (NTRS)

Dynamic blade loads, including aerodynamic, gravitational, and inertial effects, are presented for two large horizontal-axis wind turbines: the ERDA-NASA 100 kW Mod-0 and 200 kw Mod-0A wind power systems. Calculated and measured loads are compared for an experimental Mod-0 machine in operation. Predicted blade loads are also given for the higher power Mod-0A wind turbine now being assembled for operation as part of a municipal power plant. Two major structural modifications have been made to the Mod-0 wind turbine for the purpose of reducing blade loads. A stairway within the truss tower was removed to reduce the impulsive aerodynamic loading caused by the tower wake on the downwind rotor blades. Also, the torsional stiffness of the yaw drive mechanism connecting the turbine nacelle to the tower was doubled to reduce rotor-tower interaction loads. Measured reductions in load obtained by means of these two modifications equaled or exceeded predictions.

Spera, D. A.; Janetzke, D. C.; Richards, T. R.

1977-01-01

419

Plant Light Stress Tolerance across the New Mexico Elevation Gradient: Scaling from Leaf to Tower  

NASA Astrophysics Data System (ADS)

Excess light is a major abiotic component of plant stress especially when combined with sustained periods of drought. Arid and semi-arid ecosystems are regularly exposed to sustained high light, low water conditions. A network of nine Eddy Covariance towers oriented along an elevation gradient in central New Mexico has been utilized to assess differences in light use efficiency and light stress response across six distinct biomes, all of which are subjected to a semi-arid climate regulated by a seasonal monsoon. Leaf level measurements of effective quantum yield (?PSII ) and non-photochemical quenching (NPQ) parameters were taken at five of these biomes pre and post monsoon using branch mounted and hand held pulse amplitude modulated (PAM) fluorometers. Diurnal samples of leaf tissue were snap frozen to be analyzed for xanthophyll de-epoxidation state via high pressure liquid chromatography. We analyzed these leaf level parameters in the context of tower based and satellite derived measurements of NDVI, PRI and eddy covariance measures of ecosystem function including net ecosystem exchange and light use efficiency. This multi-biome, multi-scale approach aims to investigate not only leaf level photochemical response to excess light, but also how these responses are perceived by remote sensing platforms at flux tower and low earth orbit scales. We hypothesize that plant photochemical status with respect to light use efficiency and excess light mitigation strategies fluctuates as a function of elevation and the seasonal monsoon. We expect to see the highest regulatory capacity at low elevation, low precipitation sites. The NDVI and PRI signal from the tower level will track changes in ecosystem function with respect to NEE and be explained by differences in the ability of biome specific plant functional types to deal with excess light. The tower footprint, parameterized by plant functional type constituents, will be scaled to the landscape level by analysis of MODIS products.

Krofcheck, D. J.; Hanson, D.; Fox, A. M.; Litvak, M. E.

2010-12-01

420

National Wind Technology Center (Fact Sheet)  

SciTech Connect

This overview fact sheet is one in a series of information fact sheets for the National Wind Technology Center (NWTC). Wind energy is one of the fastest growing electricity generation sources in the world. NREL's National Wind Technology Center (NWTC), the nation's premier wind energy technology research facility, fosters innovative wind energy technologies in land-based and offshore wind through its research and testing facilities and extends these capabilities to marine hydrokinetic water power. Research and testing conducted at the NWTC offers specialized facilities and personnel and provides technical support critical to the development of advanced wind energy systems. From the base of a system's tower to the tips of its blades, NREL researchers work side-by-side with wind industry partners to increase system reliability and reduce wind energy costs. The NWTC's centrally located research and test facilities at the foot of the Colorado Rockies experience diverse and robust wind patterns ideal for testing. The NWTC tests wind turbine components, complete wind energy systems and prototypes from 400 watts to multiple megawatts in power rating.

Not Available

2011-12-01

421

Asian dust events observed by a 20-m monitoring tower in Mongolia during 2009  

NASA Astrophysics Data System (ADS)

A 20-m Asian dust monitoring tower was installed at Erdene in Dornogobi, Mongolia in later 2008, which is one of the high Asian dust source regions in the Asian domain, to investigate meteorological conditions for the dust events. The tower was equipped with meteorological sensors (temperature, humidity and wind speed at four levels, precipitation and pressure near the surface), radiation sensors (solar radiation, net radiation) and soil measurement sensors (soil moisture and soil temperature at three levels and soil heat flux at one level) and turbulent measurement (sonic anemometer) at the 8 m height and PM 10 concentration measurement (beta guage) at the 3 m height. Measurement was made for a full year of 2009. The observed data indicated that dust events occur all year round with the maximum hourly mean maximum concentration of 4107 ?g m -3 in the early May to a minimum of 92 ?g m -3 in later August. It was found that the dust concentration at this site is directly related to the wind speed exceeding the threshold wind speed (likewise the corresponding friction velocity) during the winter to early spring. However, the observed dust concentration is not only related to the wind speed exceeding the threshold wind speed but also to the Normalized Difference Vegetation Index (NDVI) during the late spring to the late autumn due to the growth of vegetation. It was also found that the surface soil moisture content does not affect the dust concentration due to the relatively short residence time of the soil moisture in the surface soil. The presently monitored data can be used to verify parameters used in the Asian Dust Aerosol Model (ADAM) that is the operational forecasting dust model in the Korea Meteorological Administration (KMA).

Park, Soon-Ung; Park, Moon-Soo; Chun, Youngsin

2010-12-01

422

Anomalous snowfall caused by natural-draft cooling towers  

SciTech Connect

Scattered reports of significant amounts of snow anomalously produced by cooling-tower plumes suggest that this process may be of importance. This conclusion is supported by study of high-resolution satellite images. Tabulation of a number of aerial observations of plumes at subfreezing temperatures indicates that a plume is likely to produce measurable snow if its temperature is colder than -13/sup 0/C and the saturation deficit of the ambient air is less than 0.5 g m/sup -3/. These factors are important because they affect the rates of nucleation and growth of ice particles. The rate of mixing between plume and ambient air is also important because it affects the rate of evaporation within the plume, which in turn determines the length of time available for snow particles to grow large enough to fall out. These empirically derived criteria were tested using a numerical model of cloud microphysics that simulates the most important processes of transfer of water substance between vapor, liquid, and ice, including nucleation and development of particle-size spectra. Dynamic processes were specified, not modeled. Among the many quantities computed is the flux density of snow at the base of the plume. From this, together with average fallspeed and horizontal wind speed, one can compute the amount and pattern of snowfall at the ground.

Koenig, L.R.

1980-05-01

423

Mean horizontal wind profiles measured in the atmospheric boundary layer about a simulated block building  

NASA Technical Reports Server (NTRS)

Instrumented wind towers are used to measure the three components of wind about a simulated block building. The mean horizontal wind profiles over the building are compared with wind profiles measured in the absence of the building and the wind speed deficit in the wake of the building is correlated. The turbulence intensity is of the order of 20% in the undisturbed flow whereas the free stream turbulence intensity of wind-tunnel studies is generally not more than 5%. The velocity profiles measured in the undisturbed flow zones support the representation of a neutrally stable atmospheric boundary layer with a logarithmic wind profile.

Frost, W.; Connell, J. R.; Hutto, M. L.; Fichtl, G.

1977-01-01

424

The signal shape of a tower-type ionization calorimeter  

NASA Astrophysics Data System (ADS)

The electrical model of an ionization calorimeter tower with 20×25 cm2 lateral size and 6 nuclear lengths longitudinal size is studied experimentally. The signal propagation time along the tower structure is shown to be 160 ns, the tower characteristic impedance is 5 ?. The signal is significantly influenced by dispersion. The high counting rate operation of the calorimeter concerned requires perfect termination of the detector characteristic impedance to the amplifier input impedance.

Krasnokutsky, R. N.; Kurchaninov, L. L.; Petukhov, Yu. P.; Sushkov, V. V.; Shuvalov, R. S.

1992-10-01

425

37. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER. THIS ...  

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

37. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER. THIS VIEW SHOWS TWO MAJOR CHANGES TO THE STATIC TEST TOWER: THE ADDITION OF THE NASA LOGO TO THE FACADE AND THE ADDITION OF THE UPPER STAGES TO THE JUPITER MISSILE IN THE WEST POSITION ON THE TOWER TO REPRESENT THE JUNO II CONFIGURATION. 1961, PHOTOGRAPHER UNKNOWN, FRED ORDWAY COLLECTION, U. S. SPACE AND ROCKET CENTER, HUNTSVILLE, AL. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

426

Evaluation and performance prediction of cooling tower rain zones.  

E-print Network

??Thesis (MScEng (Mechanical and Mechatronic Engineering)) – University of Stellenbosch, 2007. Cooling tower rain zone performance characteristics such as the loss coefficient and the Merkel number… (more)

Pierce, Darren John

2007-01-01

427

Optimal Inflatable Space Towers with 3 - 100 km Height  

NASA Technical Reports Server (NTRS)

Theory and computations are provided for building inflatable space towers up to one hundred kilometers in height. These towers can be used for tourism, scientific observation of space, observation of the Earth's surface, weather and upper atmosphere, and for radio, television, and communication transmissions. These towers can also be used to launch space ships and Earth satellites. These projects are not expensive and do not require rockets. They require thin strong films composed from artificial fibers and fabricated by current industry. The towers can be built using present technology. The towers can be used (for tourism, communication, etc.) during the construction process and provide self-financing for further construction. The tower design does not require work at high altitudes; all construction can be done at the Earth's surface. The transport system for a tower consists of a small engine (used only for friction compensation) located at the Earth's surface. The tower is separated into sections and has special protection mechanisms in case of damage. Problems involving security, control, repair, and stability of the proposed towers are addressed in other publications. The author is prepared to discuss these and other problems with serious organizations desiring to research and develop these projects.

Bolonkin, Alexander

2003-01-01

428

2. HI PAR (ACQUISITION RADAR) TOWER AND ENLISTED MEN (EM) ...  

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

2. HI PAR (ACQUISITION RADAR) TOWER AND ENLISTED MEN (EM) BARRACKS WITH RADAR ATTACHED. - Nike Hercules Missile Battery Summit Site, Battery Control Administration & Barracks Building, Anchorage, Anchorage, AK

429

The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers  

SciTech Connect

Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understanding the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative 'dry' cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered.

Abedi-Nik, Farhad [SADRA Institute of Higher Education, Tehran (Iran, Islamic Republic of); Sabouri-Ghomi, Saeid [K.N.T University of Technology, Tehran (Iran, Islamic Republic of)

2008-07-08

430

Numerical study of the performance of tornado-type wind energy systems  

SciTech Connect

The tornado-type wind energy system was proposed to utilize the pressure drop created by an intens vortex in a tower. The tower serves as a low pressure exhaust for the turbine. The author carried out a numerical solution of the tower flow, using the two-equation (kappa-epsilon) turbulence model, for the small size system tested by Yen, with a 0.127-m- (5-in.-) diam tower standing in a uniform wind flow. A comparison of the results with the measured pressure values verified the model. In the present work the same numerical model is used for a system with a tower that is completely embedded in an atmospheric boundary layer. The results show, for a tower in a boundary layer of the one-seventh power-law profile, about a 28% reduction of the values of power coefficient from those for a tower in a uniform stream. Calculations for the performance of a system with different tower heights and the same tower and turbine diameters show a sharp decrease of power for H/D less than or equal to 0.5. Analysis of the tangential velocity shows that the vortex should be maintained up to heights /ZETA//D less than or equal to 0.9 to avoid the decrease in power extraction. Numerical predictions are made for systems with tower diameters between 0.5 and 8 m (1.64 and 26.24 ft) using the same system geometry and approach flow conditions. The results show that the scale effect is negligible for systems of 4-m tower diameter or larger.

Ayad, S.S.

1983-03-01

431

Dynamic testing of NOVA laser switchyard tower  

NASA Astrophysics Data System (ADS)

NOVA is the latest in a series of powerful laser systems designed to study the feasibility of initiating a controlled fusion reaction by concentrating several laser beams on a small fuel target. The laser components, turning mirrors and target chamber are all mounted on large steel frame structures. These structures were analyzed via finite element models to access their seismic integrity and their overall vibrational stability. When construction was completed, a modal analysis was performed on the structures to verify and improve the finite element models. The linking of the analytical and experimental studies for the NOVA switchyard tower structure is discussed.

Weaver, H. J.; Pasternak, J. W.; Fields, D. E.

1984-06-01

432

Water-Powered Astronomical Clock Tower  

NASA Astrophysics Data System (ADS)

The construction of water-powered astronomical instruments was a long tradition of instrument making that started in the second century AD with Zhang Heng's water-powered celestial globe. The technology reached a peak when, in the eleventh century, Su Song and his team constructed the Water-Powered Astronomical Clock Tower which combined the armillary sphere, the celestial globe, and the time-keeping mechanism into a large automatic structure. Su Song's instrument contained a mechanism for controlling the water-powered movements of its wheels that amounts to an "escapement mechanism" for a mechanical clock. A new reconstruction of the mechanism is introduced in this chapter.

Sun, Xiaochun

433

Critical point wetting drop tower experiment  

NASA Technical Reports Server (NTRS)

Experiments with the wetting behavior of immiscible fluids against the container below the critical temperature are being performed in the MSFC Drop Tower Facility. Microgravity conditions extending up to three seconds (of the 4.5 second drop) are generated for the experiment. Specimens consist of glass cylindrical ampoules partially filled with fluid phases. How the fluids develop the meniscus geometry as well as hot the fluid interfaces respond to the microgravity induced oscillations is recorded during the experiment with on-board cameras. Drops are made at various temperatures to determine the interfacial energy variation as a function of temperature.

Kaulker, William F.

1988-01-01

434

Results of theoretical and experimental studies of solar wind and active galactic nuclei on LFVN VLBI network using S2 recording system  

NASA Astrophysics Data System (ADS)

We discuss the results of two sessions of observations at the Low-Frequency VLBI Network (LFVN), carried out in 1999 (INTAS99.4) and 2000 (INTAS00.3) at a wavelength of 18 cm using the S2 recording system and processed using the correlator system in Pentictone, Canada. In different configurations of the experiments on studying the solar wind and active galactic nuclei, the antennas at the following sites were employed: Medvezhji Ozera (RT-64, Special Engineering Bureau of Moscow Power Engineering Institute, Russia), Pushchino (RT-22, Pushchino Radio Astronomy Observatory, Russia), Hartebeesthoek (RT-25, South Africa), Noto (RT-32, Italy), Shanghai (RT-25, China), Pune (RT-45, India), Svetloe (RT-32, Institute of Applied Astronomy RAS, Russia). The work resulted in successful testing of the method of radio probing of the solar-wind plasma by radiation of extragalactic sources, supplemented with the method of radio interferometric reception. Spectral analysis of the obtained data allowed us to estimate the index of spatial spectrum of the electron number density.uctuations and the transfer velocity of the solar-wind inhomogeneities on the sounding path. We present and discuss the retrieved images of STA-102 quasar and the BL Lacertae object 1418+546 with millisecond angular resolution and demonstrate the results of modeling the structure of these sources.

Gavrilenko, V. G.; Nechaeva, M. B.; Pushkarev, A. B.; Molotov, I. E.; Tuccari, G.; Chebotarev, A. S.; Gorshenkov, Yu. N.; Samodurov, V. A.; Hong, X.; Quick, J.; Dougherty, S.; Ananthakrishnan, S.

2007-04-01

435

Application of a semi-spectral cloud water parameterization to cooling tower plumes simulations  

NASA Astrophysics Data System (ADS)

In order to simulate the plume produced by large natural draft cooling towers, a semi-spectral warm cloud parameterization has been implemented in an anelastic and non-hydrostatic 3D micro-scale meteorological code. The model results are compared to observations from a detailed field experiment carried out in 1980 at Bugey (location of an electrical nuclear power plant in the Rhône valley in East Central France) including airborne dynamical and microphysical measurements. Although we observe a slight overestimation of the liquid-water content, the results are satisfactory for all the 15 different cases simulated, which include different meteorological conditions ranging from low wind speed and convective conditions in clear sky to high wind and very cloudy. Such parameterization, which includes semi-spectral determination for droplet spectra, seems to be promising to describe plume interaction with atmosphere especially for aerosols and cloud droplets.

Bouzereau, Emmanuel; Musson Genon, Luc; Carissimo, Bertrand

2008-10-01

436

A Remotely Piloted Aircraft (RPA) as a Measurement Tool for Wind-Energy Research  

NASA Astrophysics Data System (ADS)

In wind energy meteorology, RPA have the clear advantage compared to manned aircraft that they allow to fly very close to the ground and even in between individual wind turbines in a wind farm. Compared to meteorological towers and lidar systems, the advantage is the flexibility of the system, which makes it possible to measure at the desired site on short notice and not only in main wind direction. At the Center of Applied Geoscience at the University of Tübingen, the research RPA MASC (Multi-purpose Airborne Sensor Carrier) was developed. RPA of type MASC have a wingspan of about 3 m and a maximum take-off weight of 7.5 kg, including payload. The standard meteorological payload includes instruments for temperature, humidity, barometric pressure and wind measurement. It is possible to resolve turbulence fluctuations of wind and temperature up to 20 Hz. The autopilot ROCS (Research Onboard Computer System), which is developed at the Institute of Flight Mechanics and Control, University of Stuttgart, makes it possible to automatically follow predefined waypoints at constant altitude and airspeed. At a cruising speed of 24 m/s and a battery life of approx. one hour, a range of 80 km is feasible. The project 'Lidar Complex', funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, is part of the research network 'WindForS', based in Southern Germany. The goal of the project is to establish lidar technology for wind energy plant site evaluation in complex terrain. Additional goals are the comparison of different measurement techniques and the validation of wind-field models in not IEC 61400 conform terrain. It is planned to design a turbulent wind-field generator, fed by real measurement data, which can be used to analyse WEC behaviour. Two test sites were defined for the 'Lidar Complex' project, one in IEC-conform terrain about 15 km from the Baltic Sea, the other in the Swabian Alb, only 2 km downstream of a 100 m steep escarpment. At both sites, flight measurements were performed in 2013 with the RPA MASC. The data that was collected allows to investigate the influence of thermal stability of the atmosphere at the test site and turbulence intensity around individual wind energy converters (WECs). Several measurement flights were done to investigate the wake structure downstream a running WEC. Preliminary results will be presented as well as an outlook for future research with the instrument.

Wildmann, Norman; Bange, Jens

2014-05-01

437

Economics of wind energy for utilities  

NASA Astrophysics Data System (ADS)

Utility acceptance of this technology will be contingent upon the establishment of both its technical and economic feasibility. This paper presents preliminary results from a study currently underway to establish the economic value of central station wind energy to certain utility systems. The results for the various utilities are compared specifically in terms of three parameters which have a major influence on the economic value: (1) wind resource, (2) mix of conventional generation sources, and (3) specific utility financial parameters including projected fuel costs. The wind energy is derived from modeling either MOD-2 or MOD-0A wind turbines in wind resources determined by a year of data obtained from the DOE supported meteorological towers with a two-minute sampling frequency. In this paper, preliminary results for six of the utilities studied are presented and compared.

McCabe, T. F.; Goldenblatt, M. K.

438

Economics of wind energy for utilities  

NASA Technical Reports Server (NTRS)

Utility acceptance of this technology will be contingent upon the establishment of both its technical and economic feasibility. This paper presents preliminary results from a study currently underway to establish the economic value of central station wind energy to certain utility systems. The results for the various utilities are compared specifically in terms of three parameters which have a major influence on the economic value: (1) wind resource, (2) mix of conventional generation sources, and (3) specific utility financial parameters including projected fuel costs. The wind energy is derived from modeling either MOD-2 or MOD-0A wind turbines in wind resources determined by a year of data obtained from the DOE supported meteorological towers with a two-minute sampling frequency. In this paper, preliminary results for six of the utilities studied are presented and compared.

Mccabe, T. F.; Goldenblatt, M. K.

1982-01-01

439

Submarine tower escape decompression sickness risk estimation.  

PubMed

Actions to enhance survival in a distressed submarine (DISSUB) scenario may be guided in part by knowledge of the likely risk of decompression sickness (DCS) should the crew attempt tower escape. A mathematical model for DCS risk estimation has been calibrated against DCS outcome data from 3,738 exposures of either men or goats to raised pressure. Body mass was used to scale DCS risk. The calibration data included more than 1,000 actual or simulated submarine escape exposures and no exposures with substantial staged decompression. Cases of pulmonary barotrauma were removed from the calibration data. The calibrated model was used to estimate the likelihood of DCS occurrence following submarine escape from the United Kingdom Royal Navy tower escape system. Where internal DISSUB pressure remains at - 0.1 MPa, escape from DISSUB depths < 200 meters is estimated to have DCS risk < 6%. Saturation at raised DISSUB pressure markedly increases risk, with > 60% DCS risk predicted for a 200-meter escape from saturation at 0.21 MPa. Using the calibrated model to predict DCS for direct ascent from saturation gives similar risk estimates to other published models. PMID:25109085

Loveman, G A M; Seddon, E M; Thacker, J C; Stansfield, M R; Jurd, K M

2014-01-01

440

29 CFR 1910.29 - Manually propelled mobile ladder stands and scaffolds (towers).  

Code of Federal Regulations, 2010 CFR

...of ladders, scaffolds, and towers shall be of adequate size...inches for mobile scaffolds (towers). Ladder stands shall have... (iii) The supporting structure for the work level shall be...level platform of scaffolds (towers) shall be of wood,...

2010-07-01

441

Wind: Our Fierce Friend  

NSDL National Science Digital Library

This site, from the Science Learning Network, is an inquiry-based learning site designed for K-12 teachers. Four main sections form the backbone of the site: Blustery Beginnings provides background materials and suggested activities to engage and motivate young students. Investigating Wind Energy provides a framework, via a series of activities, for investigating the effects and energy of wind. Current Creations suggests (and exhibits) projects that illustrate aspects of wind; and What Next? encourages site visitors to share project ideas and forge Internet-based collaborations between schools.

442

WIND ENERGY Wind Energ. (2014)  

E-print Network

the turbulent atmosphere and the wind turbine wake in order to optimize the design of the wind turbine as well.com). DOI: 10.1002/we.1792 RESEARCH ARTICLE Self-similarity and turbulence characteristics of wind turbine by a single wind turbine are studied in this paper with a new large eddy simulation (LES) code, the wind

443

Estimating the fundamental natural frequency of towers by Dunkerley's method  

NASA Astrophysics Data System (ADS)

The use of Dunkerley's first-order method for estimating the fundamental natural frequencies of tower structures is discussed. An asymmetric geometry may be considered, even though this leads to coupling between bending and torsion. The analysis of an asymmetric high-voltage transmission tower is considered as a practical example.

Trainor, P. G. S.; Shah, A. H.; Popplewell, N.

1986-09-01

444

Within compound, from Guard Tower (Building 5762), looking southwest, Technical ...  

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

Within compound, from Guard Tower (Building 5762), looking southwest, Technical Equipment Building (Building 5760) to left, Microwave Tower (associated with Building 5769) and Civil Engineering Storage Building (Building 5766) to left - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

445

VIEW LOOKING NW FROM CATWALK OF SE TOWER, SHOWING INTERIOR ...  

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

VIEW LOOKING NW FROM CATWALK OF SE TOWER, SHOWING INTERIOR ELEVATION OF TOWER OPPOSITE. NOTE THAT CONCRETE PIERS DO NOT MATCH FOOTINGS PROJECTING SLIGHTLY ABOVE WATER. - Lake Shore & Michigan Southern Railway, Bridge No. 6, Spanning Calumet River, east of Chicago Skyway (I-90), Chicago, Cook County, IL

446

16. Detail, northeast facade, operator's bow window and tower; note ...  

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

16. Detail, northeast facade, operator's bow window and tower; note condition of slates on tower skirt roof, missing section of gutter at left side of skirt roof, missing window panes; note also knee braces carried on masonry ancons; view to southwest, 90mm lens. - Southern Pacific Depot, 559 El Camino Real, San Carlos, San Mateo County, CA

447

7. SOUTHWEST CORNER OF EAST PHOTO TOWER. CLOSED WINDOW ON ...  

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

7. SOUTHWEST CORNER OF EAST PHOTO TOWER. CLOSED WINDOW ON WEST SIDE; ELECTRICAL POWER BOX ON EAST SIDE OF PHOTO TOWER. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

448

2. Keeper's house, light tower and oil house, view north, ...  

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

2. Keeper's house, light tower and oil house, view north, south and east sides of keeper's house, south side of tower and oil house - Owl's Head Light Station, Off State Highway 73 just east of Rockland on Owl's Head Bay, Owls Head, Knox County, ME

449

2. Light tower and oil house, view west, southeast and ...  

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

2. Light tower and oil house, view west, southeast and northeast sides of tower and south side of oil house - Goat Island Light Station, Goat Island, next to entrance to Cape Porpoise Harbor, just south of Trott Island, Cape Porpoise, York County, ME

450

Detail of conning tower atop the submarine. Note the wire ...  

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

Detail of conning tower atop the submarine. Note the wire rope wrapped around the base of the tower, which may have been used in an attempt to pull the submarine offshore. - Sub Marine Explorer, Located along the beach of Isla San Telmo, Pearl Islands, Isla San Telmo, Former Panama Canal Zone, CZ

451

All-Sky Imaging System on Amazon Observation Tower  

USGS Multimedia Gallery

The USGS High Dynamic Range All-Sky Imaging System (HDR-ASIS) is installed on top of a 148-foot (45-meter) observation tower to monitor changes in atmospheric conditions and the solar radiation available for photosynthesis.  The tower is located in the Amazon tropical forest near Santaré...

452

Panorama from the top of Amazon Observation Tower  

USGS Multimedia Gallery

Panorama (360 degree) view from the top of a 148-foot (45-meter) observation tower at the Amazon forest study site near Santarém, Brazil.  The instrument on the tower, the USGS High Dynamic Range All-Sky Imaging System (HDR-ASIS), monitors atmospheric conditions and the solar radiation a...

453

8. SOUTH SIDE OF EAST PHOTO TOWER; ELECTRICAL POWER BOX ...  

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

8. SOUTH SIDE OF EAST PHOTO TOWER; ELECTRICAL POWER BOX ON RIGHT. LEFT TO RIGHT IN BACKGROUND: A STORAGE SHED (BLDG. 776), METEOROLOGICAL TOWER, PYROTECHNIC SHED (BLDG. 757), AND SLC-3W MST. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

454

8. INTERIOR VIEW OF ASSEMBLY ROOM (REAR FACADE), UNTANKING TOWER, ...  

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

8. INTERIOR VIEW OF ASSEMBLY ROOM (REAR FACADE), UNTANKING TOWER, SHOWING PREVIOUS MODIFICATIONS (INSTALLATION OF METAL ROLL-UP DOOR, LEFT FOREGROUND). 125-TON LIFTING CRANE (TOP FOREGROUND), AND ORIGINAL FLOOR-TO-CEILING MULTI-PANE, METAL-CASED WINDOWS - Bonneville Power Administration Chehalis Substation, Untanking Tower, State Route 603, West of Interstate 5, Napavine, Lewis County, WA

455

32. VIEW LOOKING EAST AT THE STATIC TEST TOWER WHILE ...  

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

32. VIEW LOOKING EAST AT THE STATIC TEST TOWER WHILE A JUPITER MISSILE IS BEING POSITIONED ONTO THE TEST TOWER. DATE AND PHOTOGRAPHER UNKNOWN, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

456

Sequoias, Mavericks, Open Doors...Composing Joan Tower  

ERIC Educational Resources Information Center

This essay interview with Joan Tower is a meditation on the importance of composing, understood as a process larger than the making of new sound combinations or musical scores, suggesting that the compositional act is self-educative and self-forming. Tower's musical life, one of teaching and learning, one of composing and self-composing, is an…

Allsup, Randall Everett

2011-01-01

457

2. Barn, light tower and keeper's house, view southeast, west ...  

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

2. Barn, light tower and keeper's house, view southeast, west and north sides of barn, northwest side of light tower, and west northwest and north northeast sides of keeper's house - Curtis Island Light Station, Curtis Island, at entrance to Camden Harbor, Camden, Knox County, ME

458

1. Oil house, keeper's house, Southern Light Tower and Northern ...  

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

1. Oil house, keeper's house, Southern Light Tower and Northern Light Tower, view northwest, south and east sides - Kennebec River Light Station, South side of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

459

34. VIEW LOOKING NORTHEAST AT THE STATIC TEST TOWER. MODIFICATIONS ...  

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

34. VIEW LOOKING NORTHEAST AT THE STATIC TEST TOWER. MODIFICATIONS TO THE EAST SIDE OF THE TOWER ARE NEARING COMPLETION. NOTE THAT THE HORIZON HAS BEEN MODIFIED TO DISGUISE THE LOCATION. 1959, PHOTOGRAPHER UNKNOWN, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

460

1. Keeper's house, small boathouse, and light tower, view east, ...  

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

1. Keeper's house, small boathouse, and light tower, view east, west and south sides of keeper's house, west side of boathouse and tower - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

461

View of lifting girder and tower support superstructure on Tensaw ...  

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

View of lifting girder and tower support superstructure on Tensaw River Bridge, looking north west. Showing rope connectors and welding cut from tower removal. - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

462

1. VIEW NORTHWEST, NORTHEAST SIDE AND SOUTHEAST FRONT OF TOWER ...  

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

1. VIEW NORTHWEST, NORTHEAST SIDE AND SOUTHEAST FRONT OF TOWER AND ORIGINAL LIGHTHOUSE - Mispillion Lighthouse, Beacon Tower, South bank of Mispillion River at it confluence with Delaware River at northeast end of County Road 203, 7 miles east of Milford, Milford, Sussex County, DE

463

13. View of Truss tower and pivot pier locking east. ...  

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

13. View of Truss tower and pivot pier locking east. When the draw is open, the two arms of the truss act as cantilevers supported by the truss tower. A counterweight in the shorter of the bridge keeps the span in proper balance. - Center Street Swing Bridge, Southwest of Public Square, Cleveland, Cuyahoga County, OH

464

Cell block three and northeast guard tower (center), looking from ...  

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

Cell block three and northeast guard tower (center), looking from the central guard tower, facing northeast (note view also includes the baseball field (left), and cell blocks fourteen and eleven (right)) - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

465

Performance of a steel spar wind turbine blade on the Mod-0 100 kW experimental wind turbine  

NASA Technical Reports Server (NTRS)

The performance and loading of a large wind rotor, 38.4 m in diameter and composed of two low-cost steel spar blades were examined. Two blades were fabricated at Lewis Research Center and successfully operated on the Mod-0 wind turbine at Plum Brook. The blades were operated on a tower on which the natural bending frequency were altered by placing the tower on a leaf-spring apparatus. It was found that neither blade performance nor loading were affected significantly by this tower softening technique. Rotor performance exceeded prediction while blade loads were found to be in reasonable agreement with those predicted. Seventy-five hours of operation over a five month period resulted in no deterioration in the blade.

Keith, T. G., Jr.; Sullivan, T. L.; Viterna, L. A.

1980-01-01

466

Kaneohe, Hawaii Wind Resource Assessment Report  

SciTech Connect

The Department of Energy (DOE) has an interagency agreement to assist the Department of Defense (DOD) in evaluating the potential to use wind energy for power at residential properties at DOD bases in Hawaii. DOE assigned the National Renewable Energy Laboratory (NREL) to facilitate this process by installing a 50-meter (m) meteorological (Met) tower on residential property associated with the Marine Corps Base Housing (MCBH) Kaneohe Bay in Hawaii.

Robichaud, R.; Green, J.; Meadows, B.

2011-11-01

467

Equatorial thermospheric winds: New results using data from a network of three Fabry-Perot interferometers located in central Peru  

NASA Astrophysics Data System (ADS)

A new observing strategy aimed at improving our understanding of the properties of the equatorial thermosphere wind field, such as the vorticity and divergence, has been developed to generate maps of the thermospheric wind field. Estimates of the neutral wind are obtained from measurements of the Doppler shift of the thermospheric 630.0-nm emission obtained from a sequence of eight evenly spaced azimuthal directions for each of the three Fabry-Perot interferometer (FPI) observatories located in central Peru (Jicamarca, Nazca, and Arequipa). Measurements towards the zenith and a frequency-stabilized laser reference are also included in each sequence, which takes ~25 minutes to complete. Six of the off-zenith observing directions from the Nazca FPI observatory are used to make common volume (CV) measurements, where two of the FPIs observe the same thermospheric volume with a centroid height of ~250 km at orthogonal angles. These CV positions are located ~225 km north and south of the Nazca FPI observatory. The data obtained during a coordinated observation of the two FPIs observing the same CV location are used to compute estimates of the zonal (u) and meridional (v) wind components. The set of Doppler shifts measured by the three FPIs during a single sequence is used to produce a map of the neutral wind field for that period of time. The construction of this map is based upon the use of a first-order polynomial expansion of the neutral wind field relative to the site coordinates of each FPI location. This expansion includes the first-order gradients of u and v with respect to the zonal (x) and meridional (y) directions. Computation of the best fit in a linear least squares sense of the model expansion parameters to the Doppler shift data for all three sites determines the values of these gradient parameters. Results obtained for mid-winter 2013 show the anti-cyclonic circulation expected near the terminator generated by the day-to-night pressure gradient. Sequences of maps generated prior to midnight also illustrate how the zonal eastward circulation is modified by the introduction of the semi-diurnal tidal flow toward the geographic equator followed by the poleward reversal of this flow four to six hours later as the midnight pressure bulge passes poleward through central Peru. This technique of mapping the thermospheric wind field will be valuable as a tool for studying the variability and spatial structure of thermospheric winds near the geographic equator and may be used elsewhere for the same purpose.

Meriwether, J. W.; Dominquez, L. N.; Milla, M. A.; Chau, J. L.; Makela, J. J.; Fisher, D.

2013-12-01

468

U.S. Virgin Islands Wind Resources Update 2014  

SciTech Connect

This report summarizes the data collected from two 60-meter meteorological towers and three sonic detection and ranging units on St. Thomas and St. Croix in 2012 and 2013. These results are an update to the previous feasibility study; the collected data are critical to the successful development of a wind project at either site.

Roberts, J. O.; Warren, A.

2014-12-01

469

Dissipation of Turbulence in the Wake of a Wind Turbine  

NASA Astrophysics Data System (ADS)

The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behaviour of an individual wake as it merges with other wakes and propagates downwind is critical in assessing wind-farm power production. This evolution depends on the rate of turbulence dissipation in the wind-turbine wake, which has not been previously quantified in field-scale measurements. In situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine were collected using a tethered lifting system (TLS) carrying a payload of high-rate turbulence probes. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located near the turbine. Good agreement between the tower measurements and the TLS measurements was established for a case without a wind-turbine wake. When an operating wind turbine is located between the tower and the TLS so that the wake propagates to the TLS, the TLS measures dissipation rates one to two orders of magnitude higher in the wake than outside of the wake. These data, collected between two and three rotor diameters downwind of the turbine, document the significant enhancement of turbulent kinetic energy dissipation rate within the wind-turbine wake. These wake measurements suggest that it may be useful to pursue modelling approaches that account for enhanced dissipation. Comparisons of wake and non-wake dissipation rates to mean wind speed, wind-speed variance, and turbulence intensity are presented to facilitate the inclusion of these measurements in wake modelling schemes.

Lundquist, J. K.; Bariteau, L.

2015-02-01

470

Using a Network of Boundary Layer Profilers to Characterize the Atmosphere at a Major Spaceport  

NASA Technical Reports Server (NTRS)

Space launch, landing, and ground operations at the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida are highly sensitive to mesoscale weather conditions throughout the year. Due to the complex land-water interfaces and the important role of mesoscale circulations, a high-resolution network of five 915-MHz Doppler Radar Wind Profilers (DRWP) and 44 wind towers was installed over the KSC/CCAFS area. By using quality-controlled 915-MHz DRAT data along with the near-surface tower observations, the Applied Meteorology Unit and KSC Weather Office have studied the development and evolution of various mesoscale phenomena across KSC/CCAFS such as sea and land breezes, low-level jets, and frontal passages. This paper will present some examples of mesoscale phenomena that can impact space operations at KSC/CCAFS, focusing on the utility of the 915-MHz DRWP network in identifying important characteristics of sea/land breezes and low-level jets.

Case, Jonathan L.; Lambert, Winifred; Merceret, Francis; Ward, Jennifer

2006-01-01

471

A study of the Civic Tower in Ravenna as an example of medieval towers' preservation problems  

NASA Astrophysics Data System (ADS)

Structuralstabilityis a major item when considering very high masonry buildings made of stones, bricks, etc., that can start sudden structural failures and collapses, often without any obvious signs of warning. A famous example is the collapse of the belfry of the Basilica of San Marco in Venice --the implementation of it began in the ninth century-- which took place in July 1902 a few days after the appearanceof a fissure. This paper discusses the scientific investigation performed on the Torre Civica (Civic Tower) in Ravenna (North-East Italy), in order to characterize its constituent materials, namely bricks and mortar. All this information and relevant data merge in a multimedia database which will help to design appropriate conservation and restoration works, mainly concerning the reconstruction of the apical part of the tower, that was foreshortened ten years ago for safety reasons, starting from the original materials catalogued and preserved up to the present day.

Bruni, Stefania; Maino, Giuseppe; Marrocchino, Elena; Vaccaro, Carmela; Volpe, Lisa

2013-03-01

472

Conversion Tower for Dispatchable Solar Power: High-Efficiency Solar-Electric Conversion Power Tower  

SciTech Connect

HEATS Project: Abengoa Solar is developing a high-efficiency solar-electric conversion tower to enable low-cost, fully dispatchable solar energy generation. Abengoa’s conversion tower utilizes new system architecture and a two-phase thermal energy storage media with an efficient supercritical carbon dioxide (CO2) power cycle. The company is using a high-temperature heat-transfer fluid with a phase change in between its hot and cold operating temperature. The fluid serves as a heat storage material and is cheaper and more efficient than conventional heat-storage materials, like molten salt. It also allows the use of a high heat flux solar receiver, advanced high thermal energy density storage, and more efficient power cycles.

None

2012-01-11

473

Tower reactors for bioconversion of lignocellulosic material  

DOEpatents

An apparatus is disclosed for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material. The apparatus consists of a tower bioreactor which has mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Nguyen, Q.A.

1998-03-31

474

Tower reactors for bioconversion of lignocellulosic material  

DOEpatents

An apparatus is described for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Nguyen, Q.A.

1999-03-30

475

Optimization of class 2 tensegrity towers  

NASA Astrophysics Data System (ADS)

This paper concerns the optimal mass-to-stiffness ratio design of class-2 tensegrity towers. For different loading scenarios, the procedure seeks the topology and geometry of the structure that yields an optimal design satisfying common constraints. The domain of feasible tensegrity geometries is defined by imposing tensegrity equilibrium conditions on both unloaded and loaded structure. Remaining constraints include strength constraints for all elements of the structure and buckling constraints for bars. The symmetry of the design is imposed by restricting the domain of geometric variables and element parameters. The static response of the structure is computed by using a nonlinear large displacement model. The problem is cast in the form of a nonlinear program. The influence of material parameters on the optimal shape of the structure is investigated.

Masic, Milenko; Skelton, Robert E.

2004-07-01

476

Tower reactors for bioconversion of lignocellulosic material  

DOEpatents

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Nguyen, Quang A. (16458 W. 1st Ave., Golden, CO 80401)

1999-01-01

477

Tower reactors for bioconversion of lignocellulosic material  

DOEpatents

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards of downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Nguyen, Quang A. (16458 W. 1st Ave., Golden, CO 80401)

1998-01-01

478

Wild Wind  

NSDL National Science Digital Library

Students learn the difference between global, prevailing and local winds. They make wind vanes out of paper, straws and soda bottles and use them to measure wind direction over time. They analyze their data to draw conclusions about the local prevailing winds.

Integrated Teaching And Learning Program

479

Analysis of the vertical radon structure at the Spanish "El Arenosillo" tower station.  

PubMed

This paper presents an analysis of one year of hourly radon and meteorological measurements at 10 m and 100 m a.g.l. at El Arenosillo tall-tower station, in the south-west of the Iberian Peninsula. Whole-year and seasonal composites of the diurnal radon cycle show the expected behaviour, with larger concentrations at 10 m than at 100 m during the night, due to poor vertical mixing, and similar concentrations at both heights during the daylight hours. Wind speed and wind direction analyses by sector show the prevailing contributions for each season. Sectors with air which has spent a longer period over the ocean and high wind speeds will lead to low concentrations at both levels, whereas inland sectors show a clear increase of the concentrations with similar overall averages for the two levels. The Sierra Morena, Guadalquivir and Bethics System sectors (continental pathways) are the sectors that show higher concentrations for mild to large wind speeds. The daily evolution of radon concentration differences at both heights has been grouped into four clusters by using a K-means algorithm method. The four clusters have been selected so that they sufficiently describe different characteristics in terms of stability. The temporal evolution of the mixing height (MH) and of the bulk diffusivity parameter (Kb) during the nocturnal period has been calculated by using the temporal variation of (222)Rn concentration at 10 m and the concentration gradient with height, respectively. PMID:25464036

Vargas, A; Arnold, D; Adame, J A; Grossi, C; Hernández-Ceballos, M A; Bolivar, J P

2015-01-01

480

Power Tower Technology Roadmap and cost reduction plan.  

SciTech Connect

Concentrating solar power (CSP) technologies continue to mature and are being deployed worldwide. Power towers will likely play an essential role in the future development of CSP due to their potential to provide dispatchable solar electricity at a low cost. This Power Tower Technology Roadmap has been developed by the U.S. Department of Energy (DOE) to describe the current technology, the improvement opportunities that exist for the technology, and the specific activities needed to reach the DOE programmatic target of providing competitively-priced electricity in the intermediate and baseload power markets by 2020. As a first step in developing this roadmap, a Power Tower Roadmap Workshop that included the tower industry, national laboratories, and DOE was held in March 2010. A number of technology improvement opportunities (TIOs) were identified at this workshop and separated into four categories associated with power tower subsystems: solar collector field, solar receiver, thermal energy storage, and power block/balance of plant. In this roadmap, the TIOs associated with power tower technologies are identified along with their respective impacts on the cost of delivered electricity. In addition, development timelines and estimated budgets to achieve cost reduction goals are presented. The roadmap does not present a single path for achieving these goals, but rather provides a process for evaluating a set of options from which DOE and industry can select to accelerate power tower R&D, cost reductions, and commercial deployment.

Mancini, Thomas R.; Gary, Jesse A. (U.S. Department of Energy); Kolb, Gregory J.; Ho, Clifford Kuofei

2011-04-01

481

Wind Resource Assessment Report: Mille Lacs Indian Reservation, Minnesota  

SciTech Connect

The U.S. Environmental Protection Agency (EPA) launched the RE-Powering America's Land initiative to encourage development of renewable energy on potentially contaminated land and mine sites. EPA collaborated with the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL) and the Mille Lacs Band of Chippewa Indians to evaluate the wind resource and examine the feasibility of a wind project at a contaminated site located on the Mille Lacs Indian Reservation in Minnesota. The wind monitoring effort involved the installation of a 60-m met tower and the collection of 18 months of wind data at multiple heights above the ground. This report focuses on the wind resource assessment, the estimated energy production of wind turbines, and an assessment of the economic feasibility of a potential wind project sited this site.

Jimenez, A. C.

2013-12-01

482

Offshore Wind Power Integration in severely fluctuating Wind Conditions  

NASA Astrophysics Data System (ADS)

Strong power fluctuations from offshore wind farms that are induced by wind speed fluctuations pose a severe problem to the save integration of offshore wind power into the power supply system. Experience at the first large-scale offshore wind farm Horns Rev showed that spatial smoothing of power fluctuations within a single wind farm is significantly smaller than onshore results suggest when distributed wind farms of 160 MW altogether are connected to a single point of common-coupling. Wind power gradients larger than 10% of the rated capacity within 5 minutes require large amount of regulation power that is very expensive for the grid operator. It must be noted that a wind speed change of only 0.5m/s result in a wind power change of 10% (within the range of 9-11 m/s where the wind power curve is steepest). Hence, it is very important for the grid operator to know if strong fluctuations are likely or not. Observed weather conditions at the German wind energy research platform FINO1 in the German bight are used to quantify wind fluctuations. With a standard power curve these wind fluctuations are transfered to wind power. The aim is to predict the probability of exceedence of certain wind power gradients that occur in a time interval of e.g. 12 hours. During 2006 and 2009 the distribution of wind power fluctuations looks very similar giving hope that distinct atmospheric processes can be determined that act as a trigger. Most often high wind power fluctuations occur in a range of wind speeds between 9-12 m/s as can be expected from the shape of the wind power curve. A cluster analysis of the 500 hPa geopotential height to detect predominant weather regimes shows that high fluctuations are more likely in north-western flow. It is shown that most often high fluctuations occur in non-stable atmospheric stratification. The description of stratification by means of the vertical gradient of the virtual potential temperature is chosen to be indicative for convection, i.e. it can be assumed that a negative gradient indicates convection which leads to strong wind fluctuations in the updraft and downdraft of the cloud. Neural Networks are used to determine the probability of exceedence of wind power gradients from a set of atmospheric parameters that are taken from Numerical Weather Prediction Models. Parameters describing atmospheric stability, that are related to convection (e.g. rain rate) and that forecast wind gusts tend to carry most information to estimate expected wind power fluctuations.

von Bremen, L.

2010-09-01

483

Wind Turbine Safety and Function Test Report for the Mariah Windspire Wind Turbine  

SciTech Connect

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers to wind energy expansion by providing independent testing results for small wind turbines (SWT). In total, five turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests performed on the turbines, including power performance, duration, noise, and power-quality tests. NWTC testing results provide manufacturers with reports that may be used to meet part of small wind turbine certification requirements. The test equipment includes a Mariah Windspire wind turbine mounted on a monopole tower. L&E Machine manufactured the turbine in the United States. The inverter was manufactured separately by Technology Driven Products in the United States. The system was installed by the NWTC site operations group with guidance and assistance from Mariah Power.

Huskey, A.; Bowen, A.; Jager, D.

2010-07-01

484

Erosion and Wind Deposition  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 22 April 2003

Streamlined buttes and mesas are left as remnants of an erosive wind that has carried away sediments and even the rim of a small crater. Two wind directions are apparent in the buttes and mesas that cross each other at 90 degrees. Small dark dunes wind their way between the remnant towers, indicating that the work of the wind is an ongoing process.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude 5.3, Longitude 350.1 East (9.9 West). 19 meter/pixel resolution.

2003-01-01

485

Building designed granular towers one drop at a time.  

PubMed

A dense granular suspension dripping on an imbibing surface is observed to give rise to slender mechanically stable structures that we call granular towers. Successive drops of grain-liquid mixtures are shown to solidify rapidly upon contact with a liquid absorbing substrate. A balance of excess liquid flux and drainage rate is found to capture the typical growth and height of the towers. The tower width is captured by the Weber number, which gives the relative importance of inertia and capillary forces. Various symmetric, smooth, corrugated, zigzag, and chiral structures are observed by varying the impact velocity and the flux rate from droplet to jetting regime. PMID:22181782

Chopin, Julien; Kudrolli, Arshad

2011-11-11

486

60-Hertz electric-field exposures in transmission line towers.  

PubMed

This article reports on an investigation of 60-Hz electric-field exposures of line workers in 230- to 765-kV transmission line towers. The exposures were based on computations of the unperturbed electric field along climbing routes and at work positions on the towers and on insulated ladders suspended in towers. Computed exposures were expressed in terms of the unperturbed electric field averaged over the body as stipulated by guidelines. For the realistic on-tower positions, the worker's posture, the uniformity of the field, and the field orientation differed from the guideline exposure scenario of standing erect in a vertical uniform field. These differences suggest the need for care in comparing electric-field exposures in towers with guideline limits. The unperturbed nonuniform fields at discrete points near steel and aluminum lattice structures were computed using Monte Carlo methods that model surface and spatial electric fields on and near standard geometrical elements. To estimate a whole-body average, fields were computed at 10 discrete points positioned on segments of an articulated stick-figure model of the human body. The whole-body average field was computed from fields at all the points weighted by the fraction of body volume that the corresponding segment represented. We estimated the average unperturbed electric field, the space potential at the torso, and the induced short-circuit current for 19 climbing and work positions in six towers. The maximum average electric-field exposure during climbing ranged from 10 kV/m for a 230-kV tower to 31 kV/m for a 765-kV tower. Exposures at on-tower work positions were lower than the estimated maximum exposures during climbing. For 500- and 765-kV towers, computed exposures while climbing and at some on-tower positions exceeded the limit of 20 kV/m given in the recently adopted IEEE Standard C95.6 2002. For lower voltage towers, exposures did not exceed 20 kV/m. PMID:16048846

Bracken, T; Senior, Russell; Dudman, Joseph

2005-09-01

487

Visual Features Involving Motion Seen from Airport Control Towers  

NASA Technical Reports Server (NTRS)

Visual motion cues are used by tower controllers to support both visual and anticipated separation. Some of these cues are tabulated as part of the overall set of visual features used in towers to separate aircraft. An initial analyses of one motion cue, landing deceleration, is provided as a basis for evaluating how controllers detect and use it for spacing aircraft on or near the surface. Understanding cues like it will help determine if they can be safely used in a remote/virtual tower in which their presentation may be visually degraded.

Ellis, Stephen R.; Liston, Dorion

2010-01-01

488

Three-dimensional numerical analysis of wet cooling tower  

NASA Astrophysics Data System (ADS)

A mathematical model for water evaporation and water droplet movement is established to describe the air-water interaction in natural draft wet cooling tower (NDWCT). The standard k - epsilon model is used to close the Reynolds average Navier-Stokes equations. The three-dimensional heat and mass transfer process in NDWCT is simulated to analyze the crosswind effect on wet cooling tower performance. It is found that the heat and mass transfer in fill zone is seriously affected by crosswind, while the wet cooling tower performance is improved when crosswind velocity is higher than 5 m?s-1. Conditions and locations for good cooling performance are pointed out.

Zhao, Y. B.; Sun, F. Z.; Gao, M.; Wang, K.

2008-02-01

489

Use of nanofiltration to reduce cooling tower water usage.  

SciTech Connect

Nanofiltration (NF) can effectively treat cooling-tower water to reduce water consumption and maximize water usage efficiency of thermoelectric power plants. A pilot is being run to verify theoretical calculations. A side stream of water from a 900 gpm cooling tower is being treated by NF with the permeate returning to the cooling tower and the concentrate being discharged. The membrane efficiency is as high as over 50%. Salt rejection ranges from 77-97% with higher rejection for divalent ions. The pilot has demonstrated a reduction of makeup water of almost 20% and a reduction of discharge of over 50%.

Sanchez, Andres L.; Everett, Randy L.; Jensen, Richard Pearson; Cappelle, Malynda A.; Altman, Susan Jeanne

2010-09-01

490

Use of nanofiltration to reduce cooling tower water consumption.  

SciTech Connect

Nanofiltration (NF) can effectively treat cooling-tower water to reduce water consumption and maximize water usage efficiency of thermoelectric power plants. A pilot is being run to verify theoretical calculations. A side stream of water from a 900 gpm cooling tower is being treated by NF with the permeate returning to the cooling