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1

Wind tower service lift  

DOEpatents

An apparatus used for maintaining a wind tower structure wherein the wind tower structure may have a plurality of legs and may be configured to support a wind turbine above the ground in a better position to interface with winds. The lift structure may be configured for carrying objects and have a guide system and drive system for mechanically communicating with a primary cable, rail or other first elongate member attached to the wind tower structure. The drive system and guide system may transmit forces that move the lift relative to the cable and thereby relative to the wind tower structure. A control interface may be included for controlling the amount and direction of the power into the guide system and drive system thereby causing the guide system and drive system to move the lift relative to said first elongate member such that said lift moves relative to said wind tower structure.

Oliphant, David; Quilter, Jared; Andersen, Todd; Conroy, Thomas

2011-09-13

2

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

3

Towers for Offshore Wind Turbines  

NASA Astrophysics Data System (ADS)

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy from wind over the oceans and convert to electric energy. The advantages of offshore wind turbines as compared to land are that offshore winds flow at higher speed than onshore winds and the more available space. In some land based settings, for better efficiency, turbines are separated as much as 10 rotor diameters from each other. In offshore applications where only two wind directions are likely to predominate, the distances between the turbines arranged in a line can be shortened to as little as two or four rotor diameters. Today, more than a dozen offshore European wind facilities with turbine ratings of 450 kw to 3.6 MW exist offshore in very shallow waters of 5 to 12 m. Compared to onshore wind turbines, offshore wind turbines are bigger and the tower height in offshore are in the range of 60 to 80 m. The water depths in oceans where offshore turbines can be located are within 30 m. However as the distance from land increases, the costs of building and maintaining the turbines and transmitting the power back to shore also increase sharply. The objective of this paper is to review the parameters of design for the maximum efficiency of offshore wind turbines and to develop types offshore towers to support the wind turbines. The methodology of design of offshore towers to support the wind turbine would be given and the environmental loads for the design of the towers would be calculated for specific cases. The marine corrosion on the towers and the methods to control the corrosion also would be briefly presented. As the wind speeds tend to increase with distance from the shore, turbines build father offshore will be able to capture more wind energy. Currently two types of towers are considered. Cylindrical tubular structures and truss type structures. But truss type structures have less weight and flexibility in design. The construction of the offshore towers to harness the wind energy is also presented. The results will include the calculation of wind and wave forces on the tower and the design details for the tower.

Kurian, V. J.; Narayanan, S. P.; Ganapathy, C.

2010-06-01

4

Probabilistic analysis of mean-response along-wind induced vibrations on wind turbine towers using wireless network data sensors  

NASA Astrophysics Data System (ADS)

Wind turbine systems are attracting considerable attention due to concerns regarding global energy consumption as well as sustainability. Advances in wind turbine technology promote the tendency to improve efficiency in the structure that support and produce this renewable power source, tending toward more slender and larger towers, larger gear boxes, and larger, lighter blades. The structural design optimization process must account for uncertainties and nonlinear effects (such as wind-induced vibrations, unmeasured disturbances, and material and geometric variabilities). In this study, a probabilistic monitoring approach is developed that measures the response of the turbine tower to stochastic loading, estimates peak demand, and structural resistance (in terms of serviceability). The proposed monitoring system can provide a real-time estimate of the probability of exceedance of design serviceability conditions based on data collected in-situ. Special attention is paid to wind and aerodynamic characteristics that are intrinsically present (although sometimes neglected in health monitoring analysis) and derived from observations or experiments. In particular, little attention has been devoted to buffeting, usually non-catastrophic but directly impacting the serviceability of the operating wind turbine. As a result, modal-based analysis methods for the study and derivation of flutter instability, and buffeting response, have been successfully applied to the assessment of the susceptibility of high-rise slender structures, including wind turbine towers. A detailed finite element model has been developed to generate data (calibrated to published experimental and analytical results). Risk assessment is performed for the effects of along wind forces in a framework of quantitative risk analysis. Both structural resistance and wind load demands were considered probabilistic with the latter assessed by dynamic analyses.

Velazquez, Antonio; Swartz, Raymond A.

2011-04-01

5

Towers for Offshore Wind Turbines  

Microsoft Academic Search

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy

V. J. Kurian; S. P. Narayanan; C. Ganapathy

2010-01-01

6

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

7

Lifting system and apparatus for constructing wind turbine towers  

DOEpatents

The disclosed invention is utilized for mounting a wind turbine and blade assembly on the upper end of a wind turbine tower. The invention generally includes a frame or truss that is pivotally secured to the top bay assembly of the tower. A transverse beam is connected to the frame or truss and extends fore of the tower when the frame or truss is in a first position and generally above the tower when in a second position. When in the first position, a wind turbine or blade assembly can be hoisted to the top of the tower. The wind turbine or blade assembly is then moved into position for mounting to the tower as the frame or truss is pivoted to a second position. When the turbine and blade assembly are secured to the tower, the frame or truss is disconnected from the tower and lowered to the ground.

Livingston, Tracy; Schrader, Terry; Goldhardt, James; Lott, James

2011-02-01

8

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

9

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

10

Low-cost Triangular Lattice Towers for Small Wind Turbines  

NASA Astrophysics Data System (ADS)

This thesis focuses on the study of low-cost steel and bamboo triangular lattice towers for small wind turbines. The core objective is to determine the material properties of bamboo and assess the feasibility of bamboo towers. Using the experimentally determined buckling resistance, elastic modulus, and Poisson's ratio, a 12 m high triangular lattice tower for a 500W wind turbine has been modeled as a tripod to formulate the analytical solutions for the stresses and tower deflections, which enables design of the tower based on buckling strength of tower legs. The tripod formulation combines the imposed loads, the base distance between the legs and tower height, and cross-sectional dimensions of the tower legs. The tripod model was used as a reference for the initial design of the bamboo tower and extended to finite element analysis. A 12 m high steel lattice tower was also designed for the same turbine to serve as a comparison to the bamboo tower. The primary result of this work indicates that bamboo is a valid structural material. The commercial software package ANSYS APDL was used to carry out the tower analysis, evaluate the validity of the tripod model, and extend the analysis for the tower design. For this purpose, a 12 m high steel lattice tower for a 500 W wind turbine was examined. Comparison of finite element analysis and analytical solution has shown that tripod model can be accurately used in the design of lattice towers. The tower designs were based on the loads and safety requirements of international standard for small wind turbine safety, IEC 61400-2. For connecting the bamboo sections in the lattice tower, a steel-bamboo adhesive joint combined with conventional lashing has been proposed. Also, considering the low durability of bamboo, periodic replacement of tower members has been proposed. The result of this study has established that bamboo could be used to construct cost-effective and lightweight lattice towers for wind turbines of 500 Watt capacity or smaller. This study concludes that further work on joining of bamboo sections and weathering is required to fully utilize bamboo in practice. In comparison to steel towers, bamboo towers are economically feasible and easy to build. The tower is extremely lightweight, which justifies its application in remote areas, where the transportation is difficult.

Adhikari, Ram Chandra

11

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

12

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

13

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

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

Air flow in dry natural-draft cooling towers subject to wind. Final report  

Microsoft Academic Search

This study was performed to study the rather severe effects of wind and temperature inversions on the performance of dry, natural draft cooling towers. Cooling tower aerodynamics, meteorology, cooling tower design, heat exchanger losses, etc., were investigated. The results show that for dry, natural draft towers, the most significant wind-related losses for winds above about 5 m\\/s have to do

F. K. Moore; K. E. Torrance

1977-01-01

16

Air flow in dry natural-draft cooling towers subject to wind  

Microsoft Academic Search

Wind and temperature inversions effects on the performance of dry, natural draft cooling towers were studied. Cooling tower aerodynamics, meteorology, cooling tower design, heat exchanger losses, etc., were investigated. The results showed that for dry, natural draft towers, the most significant wind-related losses for winds above about 5 m\\/s had to do with oblique entrance to the heat exchangers; for

F. K. Moore; K. E. Torrance

1977-01-01

17

Structural health monitoring of wind towers: residual fatigue life estimation  

NASA Astrophysics Data System (ADS)

In a recent paper (Benedetti et al 2011 Smart Mater. Struct. 20 055009), the authors investigated the possibility of detecting cracks in critical sites of onshore wind towers using a radial arrangement of strain sensors around the tower periphery in the vicinity of the base welded joint. Specifically, the strain difference between adjacent strain sensors is used as a damage indicator. The number of sensors to be installed is determined by the minimum crack size to be detected, which in turn depends on the expected extreme wind conditions and programmed inspection/repair schedule. In this companion paper, we address these issues by investigating possible strategies for residual fatigue life assessment and management of onshore wind towers once the crack has been detected. For this purpose, fracture mechanics tests are carried out using welded samples to quantify the resistance to fatigue crack growth as well as the elastic-plastic fracture toughness of the welded joint at the tower base. These material strength characteristics are used to estimate (i) the critical crack size for structural integrity on the basis of fracture toughness tests, elastoplastic finite element analyses and loading spectra under extreme wind conditions, (ii) the residual life before structural collapse, applying a frequency-domain method to typical in-service wind actions and wind directionality.

Benedetti, M.; Fontanari, V.; Battisti, L.

2013-04-01

18

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

19

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

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

Tower Design Load Verification on a 1kW Wind Turbine: Preprint  

Microsoft Academic Search

Wind turbine testing at the National Wind Technology Center (NWTC) has been done to characterize both tower top loads and thrust loads for small wind turbines, which is part of an ongoing effort to model and predict small wind turbine behavior and the resulting stresses imposed on the supporting tower. To these ends, a 1-kW furling wind turbine mounted on

D. Prascher; A. Huskey

2004-01-01

22

Improving cooling efficiency of dry-cooling towers under cross-wind conditions by using wind-break methods  

Microsoft Academic Search

Cross-wind can significantly reduce cooling efficiency of natural-draft dry-cooling towers. This paper investigates solutions that may improve cooling performance of cooling towers in windy days, with particular interest in wind-break methods in and around towers. The study explores a realistic scenario with two cooling towers in-tandem arranged under cross-wind conditions. Both experimental and numerical approaches were employed to optimize the

Z. Zhai; S. Fu

2006-01-01

23

A study of the unfavorable effects of wind on the cooling efficiency of dry cooling towers  

Microsoft Academic Search

To clarify the mechanism of unfavorable effects of wind on cooling efficiency of dry cooling towers full scale measurements and wind tunnel modeling were conducted. A hot water circulation system and fin-tubular radiators were used for simulating the thermodynamic process of dry cooling towers. A dimensionless parameter, wind effect coefficient Cw, was defined and measured to describe the wind effects

Qing-ding Wei; Bo-yin Zhang; Ke-qi Liu; Xiang-dong Du; Xian-zhong Meng

1995-01-01

24

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

25

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

26

Continuous measurements of methane from a tower network over Siberia  

Microsoft Academic Search

ABSTRACT We have been conducting continuous measurements of Methane (CH4) concentration from an expanding network of towers (JR-STATION: Japan-Russia Siberian Tall Tower Inland Observation Network) located in taiga, steppe and wetland biomes of Siberia since 2004. High daytime means (>2000 ppb) observed simultaneously at several towers during winter, together with in situ weather data and NCEP\\/NCAR reanalysis data, indicate that

M. Sasakawa; K. Shimoyama; T. Machida; N. Tsuda; H. Suto; M. Arshinov; D. Davydov; A. Fofonov; O. Krasnov; T. Saeki; Y. Koyama; S. Maksyutov

2010-01-01

27

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

E-print Network

SHM BASED SYSTEM DESIGN OFA WIND TURBINE TOWER USING A MODAL SENSITIVITY BASED BAYES DETECTOR Mads of the NREL 5MW wind turbine tower subjected to bending fatigue and horizontal circumferential cracking are likely to supersede the expected life cycle costs as the design driver. The risk-willingness is small

Boyer, Edmond

28

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

2008-01-01

29

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

30

77 FR 3447 - Utility Scale Wind Towers From the People's Republic of China: Initiation of Countervailing Duty...  

Federal Register 2010, 2011, 2012, 2013, 2014

...alleges that imports of utility scale wind towers from the PRC are...industry producing utility scale wind towers. In addition...rate, underselling and price depression and suppression, reduced workforce...the CVD Petition on utility scale wind towers from the PRC...

2012-01-24

31

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

32

Effect of the Shape of the Tower Supports and Walls on the Performance of a Dry-Cooling Tower Subjected to Cross Winds  

Microsoft Academic Search

Cross winds generally reduce the heat rejection rates of natural draft dry-cooling towers. The influence of different tower support geometries and a windbreak wall on the performance of a dry-cooling tower with a horizontal heat exchanger arrangement, during windy periods, is investigated. Based on experimental results, expressions for the tangential and radial pressure loss coefficients for an array of supports

A. F. DU PREEZ; D. G. Kroeger

1995-01-01

33

Collapse and pull - down analysis of high voltage electricity transmission towers subjected to cyclonic wind  

NASA Astrophysics Data System (ADS)

Bulk electricity transmission lines are linear assets that can be very exposed to wind effects, particularly where they traverse steep topography or open coastal terrain in cyclonic regions. Interconnected nature of the lattice type towers and conductors also, present complex vulnerabilities. These relate to the direction of wind attack to the conductors and the cascading failure mechanisms in which the failure of a single tower has cascading effects on neighbouring towers. Such behaviour is exacerbated by the finely tuned nature of tower design which serves to minimize cost and reserve strength at design wind speeds. There is a clear need to better quantify the interdependent vulnerabilities of these critical infrastructure assets in the context of the severe wind hazard. This paper presents a novel methodology developed for the Critical Infrastructure Protection Modelling and Analysis (CIPMA) capability for assessing local wind speeds and the likelihood of tower failure for a range of transmission tower and conductor types. CIPMA is a program managed by the Federal Attorney-General's Department and Geoscience Australia is leading the technical development. The methodology then involves the development of heuristically derived vulnerability models that are consistent with Australian industry experience and full-scale static tower testing results, considering isolated tower loss along with three interdependent failure mechanisms to give overall likelihoods of failure.

Ahmed, Ammar; Arthur, Craig; Edwards, Mark

2010-06-01

34

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

35

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

Microsoft Academic Search

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

Abolghasem Mekanik; Mohsen Soleimani

2007-01-01

36

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

37

A note on tower wake/blade interaction noise of a wind turbine  

NASA Astrophysics Data System (ADS)

Experimental observations on wind turbine tower wake/blade interaction noise are presented. Results for circular, elliptical and square sections of the support tower legs are compared and quantified with respect to the acoustic frequency spectra produced. The results are preliminary ones obtained in a continuing study aimed at constructing a shape that may yield a lower interaction noise.

Fujii, S.; Takeda, K.; Nishiwaki, H.

1984-11-01

38

Static, seismic and stability analyses of a prototype wind turbine steel tower  

Microsoft Academic Search

Selected results of a study concerning the load bearing capacity and the seismic behavior of a prototype steel tower for a 450 kW wind turbine with a horizontal power transmission axle are presented. The main load bearing structure of the steel tower rises to almost 38 m high and consists of thin-wall cylindrical and conical parts, of varying diameters and

N Bazeos; G. D Hatzigeorgiou; I. D Hondros; H Karamaneas; D. L Karabalis; D. E Beskos

2002-01-01

39

Analytical determination of equivalent modal damping ratios of a composite tower in wind-induced vibrations  

Microsoft Academic Search

We present two methods to determine the equivalent modal damping ratios of a composite tower under wind-induced vibrations. Different damping characteristics arise from the construction of the tower with two materials; for the lower main part, say of reinforced concrete and an upper part, say of steel. The first method employs a detailed numerical integration procedure in which the static

B. C. Huang; A. Y. T. Leung; K. M. Lams; Y. K. Cheungs

1996-01-01

40

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

41

Failure analysis and risk management of a collapsed large wind turbine tower  

Microsoft Academic Search

Developing renewable energy is crucial as nations face the twin threats of global warming and a reduction in energy supplies. Wind turbines are one of the most promising sources of renewable energy in Taiwan. However, on September 28, 2008, Typhoon Jangmi struck Taiwan, bringing strong winds and heavy rainfall that collapsed a wind turbine tower located on the shore of

Jui-Sheng Chou; Wan-Ting Tu

2011-01-01

42

Investigation of wind inflow data at WERC site from a 50 meter tower  

NASA Astrophysics Data System (ADS)

In December of 2011 the University Of Wyoming Wind Energy Research Center (WERC) installed a 50 meter meteorological tower in the Laramie Valley. The tower was configured to assess the surface layer characteristics of a region surrounded by varying terrain features in all directions. The overall goal of the WERC tower is to investigate wind turbine inflow characteristics as seen at the WERC site. This thesis presents the first results and analysis of the tower data over the first 10 months of operation (14 Dec. 2011 - 22 Oct. 2012). Five minute averaged data was used to describe general inflow characteristics of the area. Measurements taken at a 10 Hz sampling rate were used to accurately characterize the turbulence under various wind speed and stability situations. A feasibility study is also discussed to indicate the viability of wind energy production in the Laramie valley.

Lehman, Nathan W.

43

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.

44

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

45

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.

46

Shaking table test and numerical analysis of offshore wind turbine tower systems controlled by TLCD  

NASA Astrophysics Data System (ADS)

A wind turbine system equipped with a tuned liquid column damper (TLCD) is comprehensively studied via shaking table tests using a 1/13-scaled model. The effects of wind and wave actions are considered by inputting response-equivalent accelerations on the shaking table. The test results show that the control effect of the TLCD system is significant in reducing the responses under both wind-wave equivalent loads and ground motions, but obviously varies for different inputs. Further, a blade-hub-tower integrated numerical model for the wind turbine system is established. The model is capable of considering the rotational effect of blades by combining Kane's equation with the finite element method. The responses of the wind tower equipped with TLCD devices are numerically obtained and compared to the test results, showing that under both controlled and uncontrolled conditions with and without blades' rotation, the corresponding responses exhibit good agreement. This demonstrates that the proposed numerical model performs well in capturing the wind-wave coupled response of the offshore wind turbine systems under control. Both numerical and experimental results show that the TLCD system can significantly reduce the structural response and thus improve the safety and serviceability of the offshore wind turbine tower systems. Additional issues that require further study are discussed.

Chen, Jianbing; Liu, Youkun; Bai, Xueyuan

2015-03-01

47

Continuous measurements of methane from a tower network over Siberia  

NASA Astrophysics Data System (ADS)

ABSTRACT We have been conducting continuous measurements of Methane (CH4) concentration from an expanding network of towers (JR-STATION: Japan-Russia Siberian Tall Tower Inland Observation Network) located in taiga, steppe and wetland biomes of Siberia since 2004. High daytime means (>2000 ppb) observed simultaneously at several towers during winter, together with in situ weather data and NCEP/NCAR reanalysis data, indicate that high pressure systems caused CH4 accumulation at subcontinental scale due to the widespread formation of an inversion layer. Daytime means sometimes exceeded 2000 ppb, particularly in the summer of 2007 when temperature and precipitation rates were anomalously high over West Siberia, which implies that CH4 emission from wetlands were exceptionally high in 2007. Many hot spots detected by MODIS in the summer of 2007 illustrate that the contribution of biomass burning also cannot be neglected. Daytime mean CH4 concentrations from the Siberian tower sites were generally higher than CH4 values reported at NOAA coastal sites in the same latitudinal zone, and the difference in concentrations between two sets of sites was reproduced with a coupled Eulerian-Lagrangian transport model. Simulations of emissions from different CH4 sources suggested that the major contributor to variation switched from wetlands during summer to fossil fuel during winter.

Sasakawa, M.; Shimoyama, K.; Machida, T.; Tsuda, N.; Suto, H.; Arshinov, M.; Davydov, D.; Fofonov, A.; Krasnov, O.; Saeki, T.; Koyama, Y.; Maksyutov, S.

2010-11-01

48

Numerical study of solar-wind tower systems for ventilation of dwellings  

Microsoft Academic Search

Numerical study is carried out of a simplified system of solar-wind tower for ventilation of dwellings. The conservation equations for mass, momentum and energy for mixed convection in two-dimensional coordinates are solved by the control volume method and Simpler algorithm. The governing parameters of the problem are Rayleigh number Ra, Reynolds number, Re (or Richardson number, Ri), the dimensionless conductivity

H. F. Nouanégué; L. R. Alandji; E. Bilgen

2008-01-01

49

Wind-induced response control and serviceability improvement of an air traffic control tower  

Microsoft Academic Search

The results are presented of a serviceability study and vibration control techniques being employed for the air traffic control tower at Incheon International Airport (IIA) on Yongjong Island, Korea. Dynamic simulations, including wind-tunnel tests, revealed that passive damping devices such as tuned mass dampers were not sufficient to satisfy the serviceability criteria and that the use of active damping systems

Wonsuk Park; Kwan-Soon Park; Hyun-Moo Koh; Dong-Ho Ha

2006-01-01

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

Tower wake/blade interaction noise of a wind turbine  

NASA Astrophysics Data System (ADS)

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

Nishiwaki, Hideo; Takeda, Katsumi

1987-10-01

52

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

53

Numerical simulation of fluid flow and thermal performance of a dry-cooling tower under cross wind condition  

Microsoft Academic Search

Using the finite volume method (FVM), the fluid flow and temperature distribution around and in a dry-cooling tower under cross wind are simulated numerically. Since the flow is turbulent, the k–? turbulence model is used. The numerical results are used to estimate the heat transfer between radiators of the tower and air around it. The numerical results are also compared

M. D. Su; G. F. Tang; S. Fu

1999-01-01

54

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

55

A Practical Application Combining Wireless Sensor Networks and Internet of Things: Safety Management System for Tower Crane Groups  

PubMed Central

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

56

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

57

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.

58

Comparison of Triton SODAR Data to Meteorological Tower Wind Measurement Data in Hebei Province, China  

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 view of this, HydroChina Corporation and the United States National Renewable Energy Laboratory (NREL) conducted a comparative test near a wind farm in Hebei Province, China. 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 traditional tower measurement program. NREL performed the initial analysis of a three-month period and sent the results to HydroChina. When another month of data became available, HydroChina and their consultant Beijing Millenium Engineering Software (MLN) repeated NREL's analysis on the complete data set, also adding sensitivity analysis for temperature, humidity, and wind speed (Section 6). This report presents the results of HydroChina's final analysis of the four-month period.

Yuechun, Y.; Jixue, W.; Hongfang, W.; Guimin, L.; Bolin, Y.; Scott, G.; Elliott, D.; Kline, D.

2012-01-01

59

The Effect of Wind Speed at the Top of the Tower on the Performance and Energy Generated from _THERMOSYPHON Solar Turbine  

NASA Astrophysics Data System (ADS)

Energy generated from wind turbine depends to a great extent on the wind speed at its inlet. The use of thermosyphon solar tower is an attempt to increase the air velocity at inlet of the wind turbine and of course to increase its power. The wind speed in a certain location changes always with time and with the height above ground surface. In this work, the effect of wind speed at the top of the tower on the performance as well as on the energy generated from thermosyphon solar turbine was studied theoretically. One location in Egypt was chosen for this study. The calculations were achieved mainly with the solar turbine located at tower bottom. For the purpose of comparison, the energy generated from the solar turbine was compared with that generated from free wind turbine at tower height with the absence of solar tower. It was found that, the wind speed at the top of the tower results in a pressure drop which affects the performance of the thermosyphon solar turbine. This pressure drop increases with the rise in wind speed and will be zero only when the wind speed at the top of the tower reaches zero. It was found also that, there is an increase in friction losses through the tower and a decrease in both temperature difference between inlet and outlet of the tower and in heat losses from tower walls with the rise in wind speed in location. The inlet air velocity to the solar turbine and consequently its specific power were found to be increased with the increase in wind speed at the top of the tower. Therefore, the effect of wind speed at the top of the tower must be taken into account during thermosyphon solar tower calculations. By comparing the performance of solar turbine and the free wind turbine located at tower height with the absence of thermosyphon solar tower, it was found that the mean inlet air velocity to the solar turbine located at tower bottom and consequently its specific power are higher than these values for free wind turbine. The mean inlet air velocity to the solar turbine is found to be 117% of its value for a free wind turbine. The yearly specific energy generated from solar turbine is expected to be 157% of its value for free wind turbine.

El-Haroun, A. A.

2002-01-01

60

Space-time VMS computation of wind-turbine rotor and tower aerodynamics  

NASA Astrophysics Data System (ADS)

We present the space-time variational multiscale (ST-VMS) computation of wind-turbine rotor and tower aerodynamics. The rotor geometry is that of the NREL 5MW offshore baseline wind turbine. We compute with a given wind speed and a specified rotor speed. The computation is challenging because of the large Reynolds numbers and rotating turbulent flows, and computing the correct torque requires an accurate and meticulous numerical approach. The presence of the tower increases the computational challenge because of the fast, rotational relative motion between the rotor and tower. The ST-VMS method is the residual-based VMS version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method, and is also called "DSD/SST-VMST" method (i.e., the version with the VMS turbulence model). In calculating the stabilization parameters embedded in the method, we are using a new element length definition for the diffusion-dominated limit. The DSD/SST method, which was introduced as a general-purpose moving-mesh method for computation of flows with moving interfaces, requires a mesh update method. Mesh update typically consists of moving the mesh for as long as possible and remeshing as needed. In the computations reported here, NURBS basis functions are used for the temporal representation of the rotor motion, enabling us to represent the circular paths associated with that motion exactly and specify a constant angular velocity corresponding to the invariant speeds along those paths. In addition, temporal NURBS basis functions are used in representation of the motion and deformation of the volume meshes computed and also in remeshing. We name this "ST/NURBS Mesh Update Method (STNMUM)." The STNMUM increases computational efficiency in terms of computer time and storage, and computational flexibility in terms of being able to change the time-step size of the computation. We use layers of thin elements near the blade surfaces, which undergo rigid-body motion with the rotor. We compare the results from computations with and without tower, and we also compare using NURBS and linear finite element basis functions in temporal representation of the mesh motion.

Takizawa, Kenji; Tezduyar, Tayfun E.; McIntyre, Spenser; Kostov, Nikolay; Kolesar, Ryan; Habluetzel, Casey

2014-01-01

61

Space-Time VMS Computation of Wind-Turbine Rotor and Tower Aerodynamics  

NASA Astrophysics Data System (ADS)

This thesis is on the space{time variational multiscale (ST-VMS) computation of wind-turbine rotor and tower aerodynamics. The rotor geometry is that of the NREL 5MW offshore baseline wind turbine. We compute with a given wind speed and a specified rotor speed. The computation is challenging because of the large Reynolds numbers and rotating turbulent ows, and computing the correct torque requires an accurate and meticulous numerical approach. The presence of the tower increases the computational challenge because of the fast, rotational relative motion between the rotor and tower. The ST-VMS method is the residual-based VMS version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method, and is also called "DSD/SST-VMST" method (i.e., the version with the VMS turbulence model). In calculating the stabilization parameters embedded in the method, we are using a new element length definition for the diffusion-dominated limit. The DSD/SST method, which was introduced as a general-purpose moving-mesh method for computation of ows with moving interfaces, requires a mesh update method. Mesh update typically consists of moving the mesh for as long as possible and remeshing as needed. In the computations reported here, NURBS basis functions are used for the temporal representation of the rotor motion, enabling us to represent the circular paths associated with that motion exactly and specify a constant angular velocity corresponding to the invariant speeds along those paths. In addition, temporal NURBS basis functions are used in representation of the motion and deformation of the volume meshes computed and also in remeshing. We name this "ST/NURBS Mesh Update Method (STNMUM)." The STNMUM increases computational efficiency in terms of computer time and storage, and computational exibility in terms of being able to change the time-step size of the computation. We use layers of thin elements near the blade surfaces, which undergo rigid-body motion with the rotor. We compare the results from computations with and without tower, and we also compare using NURBS and linear finite element basis functions in temporal representation of the mesh motion.

McIntyre, Spenser W.

62

Flue gas discharge from cooling towers. Wind tunnel investigation of building downwash effects on ground-level concentrations  

NASA Astrophysics Data System (ADS)

German power plants are required to meet new emission standards which limit the maximum sulfur dioxide (SOs) concentration in flue gas discharges to 400 mg m -3. To achieve this level of reduction in SO 2 concentration, wet scrubbing is necessary for large plants using lignite or hard coal. Wet scrubbing results in a significant reduction in the flue gas temperature leading to low effective stack heights. Instead of using stack gas reheating to achieve the plume rise necessary to satisfy local environmental standards, it was proposed to discharge the scrubbed flue gas from the existing natural-draft cooling towers (NDCT). This method should be effective in reducing local ground-level concentrations since NDCT-plumes are typically very buoyant (densimetric Froude number below 1 ) and normally reach considerable heights of rise. Only under strong wind conditions does the situation reverse itself. For such strong winds, the NDCT-plume is subject to tower and building downwash with the possibility of unacceptably high ground-level concentrations. For a 2700 MW e lignite-fired power plant near Cologne, a wind tunnel study was carried out to investigate the effects of tower and building downwash effects on the ground-level concentrations of SO 2 produced by discharging the scrubbed flue gas from the natural-draft cooling towers. Also, a comparison was made between the ground-level concentrations produced by the cooling tower discharge method and those produced by a traditional stack. It was found that for low and intermediate wind speeds, the groundlevel concentrations are lower for the case of the cooling tower discharge. Only for strong winds, which occur only very rarely at most German sites, did the conventional stack discharge appear to be superior.

Schatzmann, M.; Lohmeyer, A.; Ortner, G.

63

Structural stability of concrete wind turbines and solar chimney towers exposed to dynamic wind action  

Microsoft Academic Search

Apart from burning classical fossil resources or generating nuclear power, alternatives have been developed, like the classical ways to capture energy from wind, water and sun, or the innovative solar chimney concept.The paper presents some structural aspects of classical wind energy turbines, like their high-cycle dynamic loading and reaction as well as their fatigue behaviour. Actual research results concerning pre-stressed

Reinhard Harte; Gideon P. A. G. Van Zijl

2007-01-01

64

The IAUC Urban Flux Network - An international network of micrometeorological flux towers in urban ecosystems  

NASA Astrophysics Data System (ADS)

Throughout the past decade, numerous research groups have put significant effort into setting up new infrastructure to directly measure fluxes between various urban ecosystems and the atmosphere using micrometeorological methods - mainly eddy covariance of energy, water vapour, carbon dioxide, and aerosols. More and more long-term sites are installed in areas considered ‘typical’ for selected urban developments to quantify the impact of urban form and management on energy and greenhouse gas exchange and to support the biogeochemical modeling of urban ecosystem. Only few tall towers in urban areas are included in the FLUXNET database (http:// www.fluxnet.ornl.gov/). Most urban sites are not suitable for FLUXNET as virtually no urban site is focusing on the quantification of annual net ecosystem exchange (NEE). Urban flux-tower projects rather focus on urban-specific processes such as the role of managed urban vegetation, modified soils, urban water use, fossil-fuel emissions, the release of air pollutants, and/or anthropogenic heat fluxes. Therefore the International Association on Urban Climate (IAUC) has established the “Urban Flux Network” with the goal to network research groups and activities in the international urban flux community. The IAUC provides a simple, geographical database (http://www.urban-climate.org/) with the objective to collect and share information about ongoing and discontinued micrometeorological tower sites located in urban environments. Currently the database hosts over 30 towers from 5 continents. Example data from selected towers will demonstrate the potential of using data from a variety of urban ecosystems to quantify density effects, or the role of vegetation structure and irrigation management on the exchange of primarily energy and carbon dioxide.

Christen, A.; Grimmond, S.; Roth, M.; Pardyjak, E.

2009-12-01

65

The Effect of Wind Speed at the Top of the Tower on the Performance and Energy Generated from _THERMOSYPHON Solar Turbine  

Microsoft Academic Search

Energy generated from wind turbine depends to a great extent on the wind speed at its inlet. The use of thermosyphon solar tower is an attempt to increase the air velocity at inlet of the wind turbine and of course to increase its power. The wind speed in a certain location changes always with time and with the height above

A. A. El-Haroun

2002-01-01

66

US Wind Farmers Network  

SciTech Connect

Through this program Windustry representatives have produced, widely used, and distributed new materials and have participated in a wide variety of wind energy events, meetings, and conferences. In this work Windustry representatives have sought to reach a broad audience and grow interest and enthusiasm for wind energy. At the same time, Windustry representatives have sought to provide tools, detailed case studies, and other technical resources that deepen Windustry constituency's knowledge of wind energy options. All of this has served to facilitate development of many actual wind energy projects, particularly projects that emphasize local and community benefits.

Lisa Daniels; DOE Project Officer - Keith Bennett

2005-04-15

67

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.

2014-09-18

68

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

69

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

70

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

71

Wind energy harvesting control for green cellphone towers with dSPACE implementation  

Microsoft Academic Search

Abundance of renewable energy sources at the location of cellphone antennas and the high cost of grid expansion to remote areas provide economic incentives for development of green cellphone towers. At the height of 15–60 meter, these towers experience a semi steady flow of air suitable to generate electric power. However, some technical challenges and sizing procedures need to be

Afshin Izadian; Heng Yang; Nathaniel Girrens

2011-01-01

72

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

73

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Titan Shenyang), Titan (Suzhou) Wind Power Equipment Co., Ltd. (Titan Suzhou...and speed up the development of wind power, solar energy, and biomass energy...power project IV(5) for: ``wind power and the development and...

2012-06-06

74

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

Federal Register 2010, 2011, 2012, 2013, 2014

...nacelle and rotor blades in a wind turbine with a minimum rated electrical power generation capacity in excess...Suzhou) Co. Ltd. (Titan Wind), Titan 34.81 Lianyungang...Lianyungang), Baotou Titan Wind Power Equipment Co., Ltd....

2012-12-26

75

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

Federal Register 2010, 2011, 2012, 2013, 2014

...nacelle and rotor blades in a wind turbine with a minimum rated electrical power generation capacity in excess...Titan 34.81 percent Wind), Titan Lianyungang Metal...Lianyungang), Baotou Titan Wind Power Equipment Co., Ltd....

2013-02-15

76

Constraining CO2 tower measurements in an inhomogeneous area with anthropogenic emissions using a combination of car-mounted instrument campaigns, aircraft profiles, transport modeling and neural networks  

NASA Astrophysics Data System (ADS)

The NOAA CO2 observation network in Oregon has been enhanced by 3 new towers in 2012. The tallest tower in the network (270 m), located in Silverton in the Willamette Valley is affected by anthropogenic emissions from Oregon's busiest traffic routes and urban centers. In summer 2012, we conducted a measurement campaign using a car-mounted PICARRO CRDS CO2/CO analyzer. Over 3 days, the instrument was driven over 1000 miles throughout the northwestern portion of Oregon measuring the CO/ CO2 ratios on main highways, back roads in forests, agricultural sites, and Oregon's biggest urban centers. By geospatial analyses we obtained ratios of CO/ CO2 over distinct land cover types divided into 10 classes represented in the study area. Using the coupled WRF-STILT transport model we calculated the footprints of nearby CO/ CO2 observation towers for the corresponding days of mobile road measurements. Spatiotemporally assigned source areas in combination with the land use classification were then used to calculate specific ratios of CO (anthropogenic origins) and CO2 to separate the anthropogenic portion of CO2 from the mixing ratio time series measured at the tower in Silverton. The WRF modeled boundary layer heights used in out study showed some differences compared to the boundary layer heights derived from profile data of wind, temperature, and humidity measured with an airplane in August, September, and November 2012, repeatedly over 5 tower locations. A Bayesian Regularized Artificial Neural Network (BRANN) was used to correct the boundary layer height calculated with WRF with a temporal resolution of 20 minutes and a horizontal resolution of 4 km. For that purpose the BRANN was trained using height profile data from the flight campaigns and spatiotemporally corresponding meteorological data from WRF. Our analyses provide information needed to run inverse modeling of CO2 exchange in an area that is affected by sources that cannot easily be considered by biospheric models. The results help to account for regional anthropogenic influences using long-term tower data and supporting short-term campaigns. Figure 1: The footprint areas of 2 NOAA observation towers (72 m inlet at Walton and 212 m inlet at Silverton) during the 3-day campaign with the car-mounted PICARRO CRDS on July 10 (a), July 11 (b), and July 12 (c) 2012 together with the main roads and urban centers. The orange lines show the routes driven during those days.

Schmidt, A.; Rella, C.; Conley, S. A.; Goeckede, M.; Law, B. E.

2013-12-01

77

Atmospheric CO2 and CH4 Measurement Network on Towers in Siberia  

NASA Astrophysics Data System (ADS)

In order to estimate CO2 and CH4 fluxes at regional to sub-continental scale by an inverse model, a network of tall towers for atmospheric CO2 and CH4 measurements has been established over a region of thousand square kilometers in west Siberia. In-situ continuous measurements have been conducted at 6 stations: Berezorechka (56.17N, 84.33E) since 2002, Parabel (58.25N, 82.40E) and Igrim (63.20N, 64.48E) since 2004, Demyanskoe (59.78N, 70.87E) and Noyabrsk (63.43N, 76.76E) since 2005, and Yakutsk (62.83N, 129.35E) in east Siberia since 2005. Over next two years, installations of 4 more stations are planned. This study provides some results of observation from this network. Seasonal cycles of CO2 showed quite similar trends in growing season (May to September) among the west Siberian sites. The remarkable decrease of CO2 concentration occurred in early May and the seasonal minimum was observed between July and August. On the other hand, the short-term (from several days to week) variations in CO2 concentrations were quite different among the sites, particularly during the growing season. Rather large variation of more than 25 ppm within a week was observed during winter. The changes in CO2 concentrations at the nearby sites were almost identical. Monthly mean values of CO2 during the growing season were relatively higher at the northern sites than at southern sites. These observational results evidentially reflected the regional characteristics of CO2 flux variation, transportation, and mixing process. Daily cycles of CH4 in summer showed nocturnal increase and diurnal decrease which was due to emission of CH4 from wetland accumulated over night, and diurnal convective mixing. Relatively high concentrations of CH4 were observed in winter and summer. Because there is one of the world's vastest wetland in western Siberia, the peak of CH4 in summer implies the significant role of CH4 emissions from the west Siberian wetland to the atmosphere. On the other hand, an exceptionally high concentration of CH4 of more than 3 ppm was observed in several sites. It occurred irrespective of time of a day but was associated with the definite wind direction. This may be linked to a strong point source of CH4 such as the leakage of natural-gas from pipeline or compressor station located near the observation sites. Thus, the data presented in this study can contribute to the future effort to detect the leakage point in the pipeline using satellite data.

Shimoyama, K.; Machida, T.; Shinohara, A.; Maksyutov, S.; Arshinov, M.; Davydov, D.; Fofonov, A.; Krasnov, O.; Fedoseev, N.; Belan, B.; Belan, H.; Inoue, G.

2006-12-01

78

A virtual tall tower network for understanding continental sources and sinks of CO2  

SciTech Connect

Our understanding of the North American terrestrial carbon cycle is limited by both a lack of continental atmospheric CO2 data, and by a need for methods to interpret these and other continental data with confidence. In response to this challenge a rapid expansion of the N. American carbon cycle observational network is underway. This expansion includes a network of continuous, continental CO2 mixing ratio observations being collected at a subset of AmeriFlux towers. Progress in developing this resource includes instrument development, site installation, calibration and intercalibration efforts, and initiation of a uniform data product. Progess in applying these data include proposed methods for interpreting surface layer measurements in atmospheric inversions (the virtual tall towers approach), examination of coherence patterns in continental mixing ratios in response to weather and climate, and application of these mixing ratio measurements in formal atmospheric inversions. Future work will merge these methods with interpretation of flux towers observations of terrestrial carbon fluxes in an effort to create a single coherent diagnosis of North American terrestrial carbon fluxes over a multi-year period.

Davis, K.J.; Richardson, S.J.; Miles, N.L.

2007-03-09

79

Solving the Towers of Hanoi - how an amoeboid organism efficiently constructs transport networks.  

PubMed

Many biological systems require extensive networks to transport resources and information. Biological networks must trade-off network efficiency with the risk of network failure. Yet, biological networks develop in the absence of centralised control from the interactions of many components. Moreover, many biological systems need to be able to adapt when conditions change and the network requires modification. We used the slime mould Physarum polycephalum (Schwein) to study how the organism adapts its network after disruption. To allow us to determine the efficiency of the constructed networks, we used a well-known shortest-path problem: the Towers of Hanoi maze. We first show that while P. polycephalum is capable of building networks with minimal length paths through the maze, most solutions are sub-optimal. We then disrupted the network by severing the main connecting path while opening a new path in the maze. In response to dynamic changes to the environment, P. polycephalum reconstructed more efficient solutions, with all replicates building networks with minimal length paths through the maze after network disruption. While P. polycephalum altered some of its existing network to accommodate changes in the environment, it also reconstructed large sections of the network from scratch. We compared the results obtained from P. polycephalum with those obtained using another distributed biological system: ant colonies. We hypothesise that network construction in ants hinges upon stronger positive feedback than for slime mould, ensuring that ants converge more accurately upon the shortest path but are more constrained by the history of their networks in dynamic environments. PMID:23307798

Reid, Chris R; Beekman, Madeleine

2013-05-01

80

LQG control of horizontal wind turbines for blades and tower loads alleviation  

E-print Network

, by a continuous essay to significantly improve all aspects of a wind energy conversion system. Many research works to multi-objective MIMO methods. In [Jelavic et al. 2009], [Cutululis et al. 2002] and also in [Camblong be decomposed into several operating zones, depending on the speed of the wind that passes through the rotor

Paris-Sud XI, Université de

81

The effect of the heat exchanger arrangement and wind-break walls on the performance of natural draft dry-cooling towers subjected to cross-winds  

Microsoft Academic Search

In most full scale dry-cooling towers rectangular heat exchanger bundles are arranged either vertically around the circumference of the tower or horizontally in the inlet cross-section of the tower. A numerical procedure is used in the present paper to investigate the influence of the particular arrangement on the performance of a tower in windy conditions with the results being verified

A. F. du Preez; D. G. Kröger

1995-01-01

82

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

83

Ethics and Policy, University Health Network and University of Toronto, MaRS Centre, South Tower, Suite  

E-print Network

Ethics and Policy, University Health Network and University of Toronto, MaRS Centre, South Tower. Peter A. Singer and Abdallah S. Daar are also at the McLaughlin Centre for Molecular Medicine, MaRS> (2007) (in Spanish). 3. Séguin, B. & Hardy, B, Singer, P. A. & Daar, A. S. Human genomic variation

Cai, Long

84

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

85

Tower-supported solar-energy collector  

NASA Technical Reports Server (NTRS)

Multiple-collector tower system supports three receiver/concentrators that absorb solar energy reflected from surrounding field of heliostats. System overcomes disadvantages of tower-supported collectors. Booms can be lowered during heavy winds to protect arms and collectors.

Selcuk, M. K.

1977-01-01

86

Urban scale atmospheric inversion of CO2 emissions using a high-density surface tower network over Indianapolis area  

NASA Astrophysics Data System (ADS)

Greenhouse Gas emissions from urban areas represent a significant fraction of the overall release of fossil fuel CO2 from the surface of the globe into the atmosphere. Several ongoing efforts attempt to quantify these emissions over a few major cities across the world (i.e. Indianapolis, Los Angeles, Paris, London, Salt Lake City,...) and demonstrate the concept of atmospheric monitoring of city emissions. The accuracy of the method will highly depend on the inverse modeling framework. The atmospheric transport model and the probabilities assumed in the a priori will be used to extract the information content of surface emissions at very fine scales. But incorrect assumptions in the background emissions and concentrations or systematic errors in the local dynamics can generate artificial trends and seasonal variability in the local emissions. The construction of unbiased atmospheric modeling systems and well-defined prior errors remains a critical step in atmospheric emissions monitoring over urban areas. We present here the first inverse emission estimates over Indianapolis using a high-density surface tower network of CO2 analyzers. In order to minimize transport model errors, we developed a WRF-Chem-FDDA modeling system ingesting surface and profile measurements of horizontal mean wind, temperature and moisture in addition to the original CO2 emissions and boundary conditions. The systematic improvement of the simulated atmospheric conditions thanks to the nudging system is critical to identify and retrieve source locations at high resolution over the area. We then present an ensemble of inverse fluxes generated from varying the configuration of the inverse system in order to more accurately represent the probability space, exploring the assumptions in the a priori (i.e. the prior local urban emissions and the background atmospheric concentrations). We finally discuss the detection of trends or changes in the spatial distribution of sources at decadal time scales using two high resolution emissions products (from the Hestia project) and land cover information coupled to the WRF-Chem-FDDA system.

Lauvaux, T.; Miles, N. L.; Richardson, S.; Davis, K. J.; Deng, A.; Hardesty, R. M.; Shepson, P. B.; Cambaliza, M. L.; Iraci, L. T.; Hillyard, P. W.; Gurney, K. R.; Karion, A.; Mcgowan, L. E.; Possolo, A.; Razlivanov, I. N.; Sarmiento, D.; Sweeney, C.; Turnbull, J. C.; Whetstone, J. R.

2013-12-01

87

Distribution of GHG over West Siberia: airborne and tower network observations.  

NASA Astrophysics Data System (ADS)

In spite of high confidence level in understanding of greenhouse effect on climate change there is a lack of measurement data over significant part of the Northern Hemisphere. Taking into account the importance of the global climate changes and international cooperation in this field, NIES (National Institute for Environmental Studies) and IAO (Institute of Atmospheric Optics) combined their efforts in the framework of Joint Japanese-Russian Project on GHG monitoring to fill up this gap at least over West Siberia, which occupies a significant part of Northern Eurasia. This monitoring consists of airborne and tower network observations. Airborne study of vertical distribution of greenhouse gases nearby Novosibirsk (between 54°05'N-81°50'E and 54°35'N-82°40'E) has been started on July 1997. Monthly flight observation have been conducted at an altitude from 500 to 7000 km. The 11-year airborne study nearby Novosibirsk has revealed a positive trend in CO2 mixing ratio (>15 ppm) and the absence of a definite trend for CH4. Minimum of CO2 concentration is typically observed at the end of July. Highest annual amplitudes of CO2 mixing ratio (up to 40 ppm) are observed in the atmospheric boundary layer. During recent years a tower network (8 towers) for carbon dioxide and methane monitoring was established in West Siberia. This network covers several climatic zones from steppes in the south to northern taiga in the north (51°N to 63°N and 62°E to 82°E). In this paper we present the first results of the diurnal, seasonal, and annual behavior of these greenhouse gases in the surface atmospheric layer over West Siberia Diurnal behavior of CO2 mixing ratio showed its maximum amplitude in July and its minimum amplitude in January. Concentration gradient between northern and southern regions remains during the whole year. Carbon dioxide mixing ratio has a pronounced annual behavior with a maximum in December and a minimum in July-August. It starts to decrease on March, and this process becomes more intensive from May until July. Since the beginning of September and until December intensity of CO2 sink is smaller than the rate of its emission. Diurnal behavior of the CH4 mixing ratio is mainly neutral during the year except for the late spring and beginning of the summer when a significant one is observed. There is a CH4 concentration gradient directed from south to north with a difference in concentration from 100 to 340 ppb. In the annual behavior of CH4 concentration two maxima and two minima are observed in the center of the region under study (maxima: July and December-January; minima: April-May and October). At northern sites the main maximum is also observed in winter with one-month lag with respect to central regions. Summer maximum over southern regions is not so intensive and observed in August. Amplitude of annual behavior at northern sites is 200 ppb, and 100-120 ppb at southern. The most interannual variability is 150 ppb and observed during main and secondary maxima.

Arshinov, M. Yu.; Machida, T.; Inoue, G.; Belan, B. D.; Maksyutov, Sh.; Sasakawa, M.; Watai, T.; Shimoyama, K.; Sutoh, H.; Davydov, D. K.

2009-04-01

88

Half-hourly atmospheric 13CO2 observed by cavity ring-down spectroscopy analyzer in the USDA Forest Service Climate Tower Network  

NASA Astrophysics Data System (ADS)

Network-wide measurements of atmospheric 13CO2 enable the partitioning of global CO2 into oceanic and terrestrial sources and sinks by a 'double-deconvolution' approach. The approach is sensitive to small changes in the13C/12C signatures associated with terrestrial photosynthesis (?) and respiration (?13CR). Flask-based measurements have provided robust estimates of terrestrial 13C discrimination at seasonal time scales. These canopy-level 13C observations were in general agreement with our leaf-level understanding of physiological responses to environmental variation, though many relationships remain empirical. An improved temporal resolution of 13C measurements in stress-sensitive ecosystems by a coordinated network would strategically provide much-needed data to further develop mechanistic models for the assessment of continental-scale carbon budget. Here we present high-precision, continuous 13CO2 measurements made by Picarro cavity ring-down spectroscopy instrument at a subset of AmeriFlux towers (Wind River, GLEES, Howland, Silas Little, and Coweeta) in the new USDA Forest Service Climate Tower Network. Most of these sites have long eddy flux and meteorological records and a history of participating in syntheses. Half-hourly average CO2, H2O and 13CO2 mixing ratios have been recorded at 3 canopy heights (1m aboveground, mid- and above-canopy) since 2010. Analyzer-dependent sensitivity to temperature fluctuation, water vapor concentration, and CO2 concentration were carefully evaluated and their performances were compared between the 5 Picarro analyzers. We also compared the self-generated calibration functions with manufacturer specifications. Large discrepancies were noted in some cases, suggesting the need to independently evaluate these still-evolving spectroscopy analyzers by the users. Upon careful calibration, these analyzers were capable of producing continuous 13CO2 data that gave good agreement when compared to flask measurements. Diurnal and vertical profiles of atmospheric 13CO2 measured in the 5 USFS-managed forests are presented and discussed.

Lai, C.; Hollinger, D. Y.; Massman, W. J.; Clark, K. L.; Bible, K.; Vose, J.; Desai, A. R.; Kolka, R.; Richardson, A. D.; Hom, J. L.; Evans, R.; Forest Service Climate Tower Network

2011-12-01

89

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

90

Wind Power Plant Prediction by Using Neural Networks: Preprint  

SciTech Connect

This paper introduces a method of short-term wind power prediction for a wind power plant by training neural networks based on historical data of wind speed and wind direction. The model proposed is shown to achieve a high accuracy with respect to the measured data.

Liu, Z.; Gao, W.; Wan, Y. H.; Muljadi, E.

2012-08-01

91

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

92

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

93

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

94

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

95

Assessing and improving the representativeness of monitoring networks: The European flux tower network example  

NASA Astrophysics Data System (ADS)

It is estimated that more than 500 eddy covariance sites are operated globally, providing unique information about carbon and energy exchanges between terrestrial ecosystems and the atmosphere. These sites are often organized in regional networks like CarboEurope-IP, which has evolved over the last 15 years without following a predefined network design. Data collected by these networks are used for a wide range of applications. In this context, the representativeness of the current network is an important aspect to consider in order to correctly interpret the results and to quantify uncertainty. This paper proposes a cluster-based tool for quantitative network design, which was developed in order to suggest the best network for a defined number of sites or to assess the representativeness of an existing network to address the scientific question of interest. The paper illustrates how the tool can be used to assess the performance of the current CarboEurope-IP network and to improve its design. The tool was tested and validated with modeled European GPP data as the target variable and by using an empirical upscaling method (Artificial Neural Network (ANN)) to assess the improvements in the ANN prediction with different design scenarios and for different scientific questions, ranging from a simple average GPP of Europe to spatial, temporal, and spatiotemporal variability. The results show how quantitative network design could improve the predictive capacity of the ANN. However, the analysis also reveals a fundamental shortcoming of optimized networks, namely their poor capacity to represent the spatial variability of the fluxes.

Sulkava, Mika; Luyssaert, Sebastiaan; Zaehle, SöNke; Papale, Dario

2011-09-01

96

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.

97

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

98

Short-term Wind Power Prediction for Offshore Wind Farms -Evaluation of Fuzzy-Neural Network Based Models  

E-print Network

Short-term Wind Power Prediction for Offshore Wind Farms - Evaluation of Fuzzy-Neural Network Based of wind power capacities are likely to take place offshore. As for onshore wind parks, short-term wind is going to be a challenge. The adaptation of wind power forecasting methods to reach the specificities

Paris-Sud XI, Université de

99

Using neural networks to estimate wind turbine power generation  

Microsoft Academic Search

This paper uses data collected at Central and South West Services Fort Davis wind farm (USA) to develop a neural network based prediction of power produced by each turbine. The power generated by electric wind turbines changes rapidly because of the continuous fluctuation of wind speed and direction. It is important for the power industry to have the capability to

Shuhui Li; Donald C. Wunsch; Edgar A. O'Hair; Michael G. Giesselmann

2001-01-01

100

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

101

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/

102

Dynamics of Wind Generators on Electric Utility Networks  

Microsoft Academic Search

Dynamic interaction of wind-turbine-driven generators on electric utility networks was studied by computer simulation. Nonlinear representations of wind-turbine and various drive train elements and Park equation representations of synchronous and induction generators were implemented. An infinite capacity network was assumed. Time history responses for various system configurations were computed using as the input function severe wind gust data added to

CRAIGC. JOHNSON; RICHARDT. SMITH

1976-01-01

103

KALMAN-FILTER BASED DATA FUSION FOR NEUTRALAXIS TRACKING FOR DAMAGE DETECTION IN WIND-TURBINE TOWERS  

E-print Network

KALMAN-FILTER BASED DATA FUSION FOR NEUTRALAXIS TRACKING FOR DAMAGE DETECTION IN WIND-TURBINE Monitoring, Strain Sensors, Wind Turbine, Neutral Axis tracking, Kalman Filter INTRODUCTION Ever since to the advancements in the field of materials engineering and manufacturing methods. Newer, bigger wind turbines which

Boyer, Edmond

104

Variation in bat and bird fatalities at wind energy facilities: assessing the effects of rotor size and tower height  

Microsoft Academic Search

Wind energy is a rapidly growing sector of the alternative energy industry in North America, and larger, more productive turbines are being installed. However, there are concerns regarding bird and bat fatalities at wind turbines. To assess the influence of turbine size on bird and bat fatalities, we analyzed data from North American wind energy facili- ties. Diameter of the

Robert M. R. Barclay; E. F. Baerwald; J. C. Gruver

2007-01-01

105

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.

2014-09-18

106

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

107

Evaluation of remote sensing based terrestrial productivity from MODIS using regional tower eddy flux network observations  

Microsoft Academic Search

The Moderate Resolution Spectroradiometer (MODIS) sensor has provided near real-time estimates of gross primary production (GPP) since March 2000. We compare four years (2000 to 2003) of satellite-based calculations of GPP with tower eddy CO2 flux-based estimates across diverse land cover types and climate regimes. We examine the potential error contributions from meteorology, leaf area index (LAI)\\/fPAR, and land cover.

Faith Ann Heinsch; Maosheng Zhao; Steven W. Running; John S. Kimball; Ramakrishna R. Nemani; Kenneth J. Davis; Paul V. Bolstad; Bruce D. Cook; Ankur R. Desai; Daniel M. Ricciuto; Beverly E. Law; Walter C. Oechel; Hyojung Kwon; Hongyan Luo; Steven C. Wofsy; Allison L. Dunn; J. William Munger; Dennis D. Baldocchi; Liukang Xu; David Y. Hollinger; Andrew D. Richardson; Paul C. Stoy; Mario B. S. Siqueira; Russell K. Monson; Sean P. Burns; Lawrence B. Flanagan

2006-01-01

108

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.

Kelly Devereaux

2013-01-01

109

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

110

Comparison of natural and artificial forcing to study the dynamic behaviour of bell towers in low wind context by means of ground-based radar interferometry: the case of the Leaning Tower in Pisa  

NASA Astrophysics Data System (ADS)

The study of Cultural Heritage assets needs the application of non-destructive and non-invasive monitoring techniques. In particular, monuments and historical buildings which are open to the visitors and/or subject to important stress must be studied for their dynamic response. In the last 10?years the new ground-based radar interferometry technology has been developed allowing to monitor displacements from a point of sight far from the studied targets. It virtually provides a continuous mapping of displacements of the observed structures up to 10?µm with a range resolution of 0.75?m. In this paper, the application of ground-based interferometry on one very important historical building, the Leaning Tower of Pisa in Italy, is reported. The analysis of these kind of structures is important to catch their dynamic response to natural actions in general, and also to assess the effects due to pedestrian and users, and consequently to define functional capabilities and levels of acceptable dynamic stress. The studied structure was subject to artificial loading by synchronous movement of about 20 people. Artificial forcing led the structure to a resonance condition with the same frequency of the one due to the natural noise excitation, which was separately measured, and with an oscillation amplitude more than thirty times greater than the natural one (in conditions of weak wind). During the passive stages of the survey the recorded structural vibrations were very closed to the instrumental sensitivity, making difficult to distinguish vibration amplitudes amplifications of various segments at various heights. Through the spectral analysis of the acquired data it was possible to estimate the vibration frequencies of the first modal shapes of the structure along two orthogonal directions. The power spectra of the passive survey data have the same maximum frequency of the active but contain more noise at low frequency.

Marchisio, Mario; Piroddi, Luca; Ranieri, Gaetano; Calcina, Sergio V.; Farina, Paolo

2014-10-01

111

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

112

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

113

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

E-print Network

for modeling control sys- tems and networks exist such as Matlab/Simulink [15], a software tool extensivelyNetworked Control System Wind Tunnel (NCSWT)- An evaluation tool for networked multi-agent systems-physical systems, such groups of unmanned aerial vehicles, are often monitored and controlled by networked control

Koutsoukos, Xenofon D.

114

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.

Mission Science Workshop

2013-01-01

115

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

116

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

117

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

118

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

119

Impact of wind generation on voltage stability in low-voltage distribution networks  

Microsoft Academic Search

This paper aims to study and provide understanding on the impact of wind generation on voltage stability in distribution networks taking into consideration the intermittent nature of wind generation. For this purpose a 61-bus radial distribution network has been modelled in Powerworld® simulator. Wind generation is connected at different locations of the network and these locations are identified as critical

I. S. Naser; A. Garba; O. Anaya-Lara; K. L. Lo

2009-01-01

120

'Towers in the Tempest' Computer Animation Submission  

NASA Technical Reports Server (NTRS)

The following describes a computer animation that has been submitted to the ACM/SIGGRAPH 2008 computer graphics conference: 'Towers in the Tempest' clearly communicates recent scientific research into how hurricanes intensify. This intensification can be caused by a phenomenon called a 'hot tower.' For the first time, research meteorologists have run complex atmospheric simulations at a very fine temporal resolution of 3 minutes. Combining this simulation data with satellite observations enables detailed study of 'hot towers.' The science of 'hot towers' is described using: satellite observation data, conceptual illustrations, and a volumetric atmospheric simulation data. The movie starts by showing a 'hot tower' observed by NASA's Tropical Rainfall Measuring Mission (TRMM) spacecraft's three dimensional precipitation radar data of Hurricane Bonnie. Next, the dynamics of a hurricane and the formation of 'hot towers' are briefly explained using conceptual illustrations. Finally, volumetric cloud, wind, and vorticity data from a supercomputer simulation of Hurricane Bonnie are shown using volume techniques such as ray marching.

Shirah, Greg

2008-01-01

121

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

E-print Network

1 Fourth International Workshop on Large-Scale Integration of Wind Power and Transmission Networks of Denmark, B. 321, DK-2800 Lyngby, Denmark, csm@imm.dtu.dk Two wind power prognosis criteria and regulating of criterion in short-term wind power prognosis. This is done by investigating the consequences of choice

122

Upward lightning observations from towers in Rapid City, South Dakota and comparison with National Lightning Detection Network data, 2004-2010  

NASA Astrophysics Data System (ADS)

We report on upward lightning observations from ten tall towers (91-191 m) in Rapid City, South Dakota, USA and compare with National Lightning Detection Network (NLDN) data. A total of 81 upward flashes were observed from 2004-2010 using GPS time-stamped optical sensors, and in all but one case, visible flash activity preceded the development of the upward leaders. Time-correlated analysis showed that the NLDN recorded an event within 50 km of towers and within 500 ms prior to upward leader development from the tower(s) for 83% (67/81) of the upward flashes. A preceding positive cloud-to-ground stroke (+CG) was detected in 57% (46/81) of the cases, and a preceding positive intracloud flash (+IC) in 23% (19/81) of the cases. However, 8 of the 19 NLDN-indicated +IC events were actually +CG strokes based on optical observations. Preceding negative intracloud flashes (-IC) were recorded for 2% (2/81) of the cases. Analysis also showed that for 44% (36/81) of the upward flashes, the NLDN reported subsequent negative cloud-to-ground (-CG) strokes and/or -IC events at one or more tower locations. Of the 151 subsequent events, 70% (105/151) were -CG reports and 30% (46/151) were listed as -IC events. The geometric mean/median location accuracy and peak current for subsequent events were 194 m/206 m and -12.9 kA/-12.4 kA respectively. These correlated observations suggest that a majority of the upward lightning flashes were triggered by a preceding flash with the dominant triggering type being the +CG flash.

Warner, Tom A.; Cummins, Kenneth L.; Orville, Richard E.

2012-10-01

123

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

124

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

125

Wind power forecasting using advanced neural networks models  

Microsoft Academic Search

In this paper, an advanced model, based on recurrent high order neural networks, is developed for the prediction of the power output profile of a wind park. This model outperforms simple methods like persistence, as well as classical methods in the literature. The architecture of a forecasting model is optimised automatically by a new algorithm, that substitutes the usually applied

G. N. Kariniotakis; G. S. Stavrakakis; E. F. Nogaret

1996-01-01

126

Nocturnal wind direction shear and its potential impact on pollutant transport  

SciTech Connect

The estimation of transport and diffusion of airborne pollutants during the nighttime is challenging, especially over complex terrain where gravity driven drainage flows may be overlain with wind from a different direction. This study investigates the character of wind direction shear in the lowest 100 m using tower measurements from a complex, semi-arid site where local thermally-driven flows are common. the effects of wind direction shear on plume transport are studied by simulating a hypothetical elevated term release. This is accomplished by first simulating transport and dispersion using wind measurements from only the 12-m level from a network of towers. This case represents the approach commonly taken at many facilities where a network of short towers is available. Then the release is modeled using wind measurements made at four levels in the lowest 100 m. The differences between the two simulations are significant and would lead to very different responses in an emergency situation.

Bowen, B.M.; Baars, J.A.; Stone, G.L.

1997-09-01

127

Nocturnal wind direction shear and its potential impact on pollutant transport  

SciTech Connect

The estimation of transport and diffusion of airborne pollutants during the nighttime is challenging, especially over complex terrain where gravity driven drainage flows may be overlain with wind from a different direction. This study investigates the character of wind direction shear in the lowest 100 m using tower measurements from a complex, semi-arid site where local thermally-driven flows are common. The effects of wind direction shear on plume transport are studied by simulating a hypothetical elevated term release. This is accomplished by first simulating transport and dispersion using wind measurements from only the 12-m level from a network of towers. This case represents the approach commonly taken at many facilities where a network of short towers is available. Then the release is modeled using wind measurements made at four levels in the lowest 100 m. The differences between the two simulations are significant and would lead to very different responses in an emergency situation.

Bowen, B.M. [Lawrence Livermore National Lab., CA (United States); Baars, J.A.; Stone, G.L. [Los Alamos National Lab., NM (United States)

1998-12-31

128

76 FR 10328 - Grant of Authority for Subzone Status; Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs, Blades and Towers...special-purpose subzone at the wind turbine nacelle, hub, blade and tower manufacturing...manufacturing and warehousing of wind turbine nacelles, hubs, blades and towers...

2011-02-24

129

Devil's Tower Geology  

NSDL National Science Digital Library

This site from the National Park Service briefly addresses the geology of Devil's Tower. The evolution of various theories on the formation of the tower are discussed. A slide show of the emplacement of the tower is also available.

National Park Service (NPS)

130

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

131

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

132

Frequency control of isolated network with wind and diesel generators by using fuzzy logic controller  

Microsoft Academic Search

Due to the recent expansion of renewable energy applications, wind energy conversion is receiving much interest all over the world. However, output fluctuations of wind generators cause network frequency variations in power systems. This can decrease the power quality and then cause a restriction of wind farm installation, especially in an isolated network, for example, electrical power system in a

Hany M. Hasanien; S. M. Muyeen; J. Tamura

2009-01-01

133

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

134

Design of a Wind Power Generation Monitoring System Based on Wireless Sensor Network  

Microsoft Academic Search

Wind energy is one kind of purity, non-polluting, renewable new energy. Real-time monitoring wind power generation system is an important action bearing with steady operation of system and high efficiency exploiting wind power resources. A novel intelligent monitoring system plan for wind power generation based on wireless sensor networks is proposed in this paper, which employs many high technologies such

Li Lin; Shen Ming-xia

2010-01-01

135

Prediction of geomagnetic storms from solar wind data using Elman recurrent neural networks  

Microsoft Academic Search

In order to accurately predict geomagnetic storms, we exploit Elman recurrent neural networks to predict the Dst index one hour in advance only from solar wind data. The input parameters are the interplanetary magnetic field z-component Bz (GSM), the solar wind plasma number density n and the solar wind velocity V. The solar wind data and the geomagnetic index Dst

Jian-Guo Wu; Henrik Lundstedt

1996-01-01

136

LWST Phase I Project Conceptual Design Study: Evaluation of Design and Construction Approaches for Economical Hybrid Steel\\/Concrete Wind Turbine Towers; June 28, 2002 -- July 31, 2004  

Microsoft Academic Search

The United States Department of Energy (DOE) Wind Energy Research Program has begun a new effort to partner with U.S. industry to develop wind technology that will allow wind systems to compete in regions of low wind speed. The Class 4 and 5 sites targeted by this effort have annual average wind speeds of 5.8 m\\/s (13 mph), measured at

LaNier

2005-01-01

137

Designing laboratory wind simulations using artificial neural networks  

NASA Astrophysics Data System (ADS)

While experiments in boundary layer wind tunnels remain to be a major research tool in wind engineering and environmental aerodynamics, designing the modeling hardware required for a proper atmospheric boundary layer (ABL) simulation can be costly and time consuming. Hence, possibilities are sought to speed-up this process and make it more time-efficient. In this study, two artificial neural networks (ANNs) are developed to determine an optimal design of the Counihan hardware, i.e., castellated barrier wall, vortex generators, and surface roughness, in order to simulate the ABL flow developing above urban, suburban, and rural terrains, as previous ANN models were created for one terrain type only. A standard procedure is used in developing those two ANNs in order to further enhance best-practice possibilities rather than to improve existing ANN designing methodology. In total, experimental results obtained using 23 different hardware setups are used when creating ANNs. In those tests, basic barrier height, barrier castellation height, spacing density, and height of surface roughness elements are the parameters that were varied to create satisfactory ABL simulations. The first ANN was used for the estimation of mean wind velocity, turbulent Reynolds stress, turbulence intensity, and length scales, while the second one was used for the estimation of the power spectral density of velocity fluctuations. This extensive set of studied flow and turbulence parameters is unmatched in comparison to the previous relevant studies, as it includes here turbulence intensity and power spectral density of velocity fluctuations in all three directions, as well as the Reynolds stress profiles and turbulence length scales. Modeling results agree well with experiments for all terrain types, particularly in the lower ABL within the height range of the most engineering structures, while exhibiting sensitivity to abrupt changes and data scattering in profiles of wind-tunnel results. The proposed approach allows for quicker and more effective achieving targeted flow and turbulence features of the ABL wind-tunnel simulations as compared to the common trial and error procedures. This methodology is expected to enable wind-tunnel modelers a quick and time-efficient designing of ABL simulations in studies dealing with air pollutant dispersion, wind loading of structures, wind energy, and urban micrometeorology, where atmospheric flow and turbulence play a key role.

Križan, Josip; Gašparac, Goran; Kozmar, Hrvoje; Antoni?, Oleg; Grisogono, Branko

2014-06-01

138

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

139

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

140

A novel control of a small wind turbine driven generator based on neural networks  

Microsoft Academic Search

This paper presents a novel control strategy of turbine directly driven permanent magnet synchronous generator (PMSG) for a small wind generation system. Compared to the traditional techniques, this new method has following advantages: 1) the proposed neural networks provides a fast and accurate estimation of actual wind velocity without anemometer; 2) the maximum mechanical power of small wind turbine can

K. L. Shi; H. Li

2004-01-01

141

Large-scale wind power integration and voltage stability limits in regional networks  

Microsoft Academic Search

When planning and developing large-scale wind power plants in areas distant from the main power transmission system, voltage control assessments and reactive power compensation are increasingly important. Voltage stability of the regional network may be a main limitation with respect to maximum rating and operation of the wind power plant Technical constraints in relation to wind power integration in weak

M. P. Palsson; T. Toftevaag; K. Uhlen; J. O. G. Tande

2002-01-01

142

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.

IEEE

2014-05-22

143

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

144

The Economic Implications of Adding Wind Capacity to a Bulk Power Transmission Network  

E-print Network

The Economic Implications of Adding Wind Capacity to a Bulk Power Transmission Network by Tim Mount. * Corresponding author, tdm2@cornell.edu. #12;2 The Economic Implications of Adding Wind Capacity to a Bulk Power limitations of solving large AC Optimal Power Flows (OPF) for real networks, system operators typically use

145

Plant Vogtle cooling tower studies  

SciTech Connect

Intensive ground-based field studies of plumes from two large, natural-draft cooling towers were conducted in support of the MTI modeling effort. Panchromatic imagery, IR imagery, meteorological data, internal tower temperatures and plant power data were collected during the field studies. These data were used to evaluate plume simulations, plume radioactive transfer calculations and plume volume estimation algorithms used for power estimation. Results from six field studies indicate that a 3-D atmospheric model at sufficient spatial resolution can effectively simulate a cooling tower plume if the plume is of sufficient size and the ambient meteorology is known and steady. Small plumes and gusty wind conditions degrade the agreement between the simulated and observed plumes. Thermal radiance calculations based on the simulated plumes produced maximum IR temperatures (near tower exit) which were in good agreement with measured IR temperatures for the larger plumes. For the smaller plumes, the calculated IR temperature was lower than the measured temperature by several degrees. Variations in maximum IR plume temperature with decreasing power (one reactor was undergoing a shutdown process), were clearly observed in the IR imagery and seen in the simulations. These temperature changes agreed with those calculated from an overall tower energy and momentum balance. Plume volume estimates based on camcorder images at three look angles were typically 20--30 percent larger than the plume volumes derived from the simulations, although one estimate was twice the simulated volume. Volume overestimation is expected and will have to be accounted for to some degree if plume volume is to be a useful diagnostic quantity in power estimation. Volume estimation with MTI imagery will require a large, stable plume and two looks in the visible bands (5m GSD) along with a solar shadow.

O'Steen, L.

2000-01-26

146

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

147

WindTalker: A P2P-Based Low-Latency Anonymous Communication Network  

NASA Astrophysics Data System (ADS)

Compared with traditional static anonymous communication networks, the P2P architecture can provide higher anonymity in communication. However, the P2P architecture also leads to more challenges, such as route, stability, trust and so on. In this paper, we present WindTalker, a P2P-based low-latency anonymous communication network. It is a pure decentralized mix network and can provide low-latency services which help users hide their real identity in communication. In order to ensure stability and reliability, WindTalker imports “seed nodes” to help a peer join in the P2P network and the peer nodes can use gossip-based protocol to exchange active information. Moreover, WindTalker uses layer encryption to ensure the information of relayed messages cannot be leaked. In addition, malicious nodes in the network are the major threat to anonymity of P2P anonymous communication, so WindTalker imports a trust mechanism which can help the P2P network exclude malicious nodes and optimize the strategy of peer discovery, tunnel construction, and relaying etc. in anonymous communications. We deploy peer nodes of WindTalker in our campus network to test reliability and analyze anonymity in theory. The network measurement and simulation analysis shows that WindTalker can provide low-latency and reliable anonymous communication services.

Zhang, Jia; Duan, Haixin; Liu, Wu; Wu, Jianping

148

Cooling Towers- Energy Conservation Strategies Understanding Cooling Towers  

E-print Network

COOLING TOWERS - ENERGY CONSERVATION STRATEGIES UNDERSTANDING COOLING TOWERS MATT SMITH L.S. Enterprises Fort Myers, Florida Cooling towers are energy conservation devices that Management, more often than not, historically overlooks...

Smith, M.

149

Diurnal variation of horizontal wind direction fluctuations in complex terrain at Geysers, Cal  

Microsoft Academic Search

Horizontal diffusion in the surface layer is dependent on the standard deviation of wind direction fluctuations ??. Diurnal variation of this parameter in complex terrain was studied for the July 1979 Geysers, Cal., experiment using data from a network of 11 short meteorological towers in the 25 km2 Anderson Creek watershed Valley side slopes are roughly 20 ° and maximum

Steven R. Hanna

1981-01-01

150

Neural network based control of Doubly Fed Induction Generator in wind power generation  

NASA Astrophysics Data System (ADS)

To complement the other types of pollution-free generation wind energy is a viable option. Previously wind turbines were operated at constant speed. The evolution of technology related to wind systems industry leaded to the development of a generation of variable speed wind turbines that present many advantages compared to the fixed speed wind turbines. In this paper the phasor model of DFIG is used. This paper presents a study of a doubly fed induction generator driven by a wind turbine connected to the grid, and controlled by artificial neural network ANN controller. The behaviour of the system is shown with PI control, and then as controlled by ANN. The effectiveness of the artificial neural network controller is compared to that of a PI controller. The SIMULINK/MATLAB simulation for Doubly Fed Induction Generator and corresponding results and waveforms are displayed.

Barbade, Swati A.; Kasliwal, Prabha

2012-07-01

151

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

152

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

153

Impact of SCIG and DFIG Type Wind Turbine on the Stability of Distribution Networks: static and dynamic  

E-print Network

Impact of SCIG and DFIG Type Wind Turbine on the Stability of Distribution Networks: static fed induction generator (DFIG) type wind turbine in distribution networks. The analysis is carried out and DFIG type wind turbines have significant impact on the static voltage stability, power loss

Pota, Himanshu Roy

154

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

155

Leaning Tower of PESA  

ERIC Educational Resources Information Center

There is a certain similarity between the Philosophy of Education Society of Australasia (PESA) and the leaning tower of Pisa. Both have a certain presence on the landscape: the tower has a commanding appearance on the Italian countryside while PESA has left its mark on the academic fabric of Australasia. Both are much loved: Pisa by visiting…

Clark, John

2009-01-01

156

Lost Subways: Tower Hill  

NSDL National Science Digital Library

This interesting website reviews "lost subways," including photos, articles, and other historical information. The Tower Hill Subway was England's first tube railway under the Thames which was open for public use from 1870-1896. This page offers an overview, timeline, history, description of the tunnel (in French), a bibliography, and a list of online resources about the Tower Hill Subway.

Delaitre, Frederic

157

Super Golf Tower  

NSDL National Science Digital Library

In this engineering activity, challenge learners to build a tower out of 10 sheets of newspaper and 3 feet of masking tape, which can hold a golf ball balancing at the top. Learners explore ways to strengthen the paper tower as well as stabilize it to hold the ball.

WGBH Boston

2002-01-01

158

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

159

Wind farm control for stabilisation of electrical networks based on passivity  

Microsoft Academic Search

This article presents a control strategy for wind farms equipped with doubly fed induction generators (DFIG) operating in a network with a complex load. As is known from vector control theory, DFIG are able to generate active and reactive powers in an independent way. Therefore, taking into account a unitary power factor, a wind farm control law based on the

R. D. Fernández; R. J. Mantz; P. E. Battaiotto

2010-01-01

160

Modal Analysis of a DFIG-Based Wind Farm Interfaced With a Series Compensated Network  

Microsoft Academic Search

Interests of subsynchronous resonance (SSR) in series compensated electric networks with wind power penetration have arisen recently. To better understand the nature of such systems, modal analysis of a doubly-fed induction generator (DFIG)-based wind energy system interconnected with a series compensated elec- tric network is conducted in this paper. The system model is built in Matlab\\/Simulink. The major contributions of

Lingling Fan; Chanxia Zhu; Zhixin Miao; Minqiang Hu

2011-01-01

161

Gone with the Wind ON_Mars (GOWON): A Wind-Driven Networked System of Mobile Sensors on Mars  

E-print Network

We propose a revolutionary way of studying the surface of Mars using a wind-driven network of mobile sensors- Gone with the Wind ON_Mars (GOWON). GOWON is a scalable architecture that will allow in-situ mapping of a wide range of phenomena, exploiting existing capabilities, but radically improving our ability to study Mars. GOWON has the following characteristics: 1.it consists of a dynamic wireless network of many compact mobile sensors. 2.the mobile sensors (called moballs) are spherically-shaped and wind-driven; they are lightweight and bouncy. 3. moballs communicate with each other and earth through a satellite system orbiting Mars. There is also peer-to-peer communication between the moballs, creating a network of shared data, computing, and tasks. Motivation and Rationale Thanks to earlier exploration missions to Mars we now have a much better understanding of many of the natural characteristics of the red planet. We now know that there is an abundance of wind (with average speeds of 10 m/s and much hig...

Davoodi, Faranak; Murphy, Neil; Mischna, Michael; Nesnas, Issa; Nikzad, Shouleh

2012-01-01

162

Testing of lattice towers for Ontario Hydro transmission line refurbishment program  

SciTech Connect

This paper reports, as part of the ongoing transmission line refurbishment study, three single circuit 115 kV, Kingston type suspension towers on rock-anchor foundations tested to failure. The type of loads applied on the towers were chosen to represent unbalanced loads due to broken skywire and conductor, heavy ice, strong wind and wind-on-ice loads. Selected tower members and foundations were instrumented to measure the member loads, tower deflections and foundation movement during various stages of testing. The measured values were compared with the corresponding predicted values. The correlation is good between the predicted and actual tower failure loads. The tower tests confirmed that there is reserve strength available for upgrading the conductor on this line. The measured tower member loads and foundation loads correlated fairly satisfactorily with the corresponding calculated values. The rock-anchor foundation did not show any movement at all.

Krishnasamy, S.G.; Senkiw, G.A.; Havard, D.G.; Pon, C.J.; Tabatabai, M.; Hathout, I.; Radhakrishna, H.S.; Tsang, R.H.K. (Ontario Hydro, Toronto, ON (Canada))

1990-07-01

163

Neural networks for condition monitoring of wind turbines  

Microsoft Academic Search

Wind energy is the renewable energy source considered a hope in future as a clean and sustainable energy, as can be seen by the growing number of wind farms all over the world. With the huge proliferation of wind farms, as an alternative to the traditional fossil power generation, the economic issues dictate the necessity of monitoring systems to optimize

R. F. Mesquita Brandao; J. A. Beleza Carvalho; F. P. Maciel Barbosa

2010-01-01

164

Concept study and validation of Antarctic telescope tower  

NASA Astrophysics Data System (ADS)

Studies by Mark Swain and a colleague at the Max Planck Institut fur Astronomie, coupled with results from past and ongoing projects at Harvey Mudd College, strongly suggest that it may be possible to achieve imaging performance comparable to the Hubble Space Telescope at relatively low cost using available, commercial products. This is achievable by placing a 2.4 m telescope, with readily available adaptive optics, on a 30 m tower located at a high-elevation geological "dome" in Antarctica. An initial project surveyed relevant tower design approaches, then generated and evaluated six concept designs for telescope towers. Using data for typical and extreme wind at Dome C to generate wind loads, finite element analysis yielded lateral deflections at the top of 0.3 mm for typical winds and 12.1 mm for extreme gusts, with the lowest resonant frequency at 0.7 Hz; some tower concepts are innovative and allow for easy shipment, setup, and relocation. A subsequent project analyzed a tower designed by Hammerschlag and found fundamental resonance frequencies at 4.3 Hz for bending and 5.9 Hz for torsion; this project also designed and simulated an active telescope control system that maintained 17 milliarcsecond pointing error for the telescope atop the tower during typical wind conditions.

Lanford, Ephraim; Swain, Mark; Meyers, Catherine; Muramatsu, Tamao; Nielson, Greg; Olson, Valerie; Ronsse, Sebastien; Vinding Nyden, Emily; Hammerschlag, Robert; Little, Patrick

2006-06-01

165

Solar Updraft TowersSolar Updraft Towers Presentation 5  

E-print Network

Solar Updraft TowersSolar Updraft Towers CEE 491 Presentation 5 Travis Satsuma May 5, 2009 #12 Benefits Solar tower built in the desert, instigates plant growth Condensation created at night enlivens turbines running 24/7 CO2 only produced during construction of tower #12;HistoryHistory In 1903, Catalan

Prevedouros, Panos D.

166

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

167

Potential errors in using one anemometer to characterize the wind power over an entire rotor disk  

NASA Technical Reports Server (NTRS)

Wind data collected at four levels on a 90-m tower in a prospective wind farm area are used to evaluate how well the 10-m wind speed data with and without intermittent vertical profile measurements compare with the 90-m tower data. If a standard, or even predictable, wind speed profile existed, there would be no need for a large, expensive tower. This cost differential becomes even more significant if several towers are needed to study a prospective wind farm.

Simon, R. L.

1982-01-01

168

FIELD INVESTIGATION OF COOLING TOWER AND COOLING POND PLUMES  

EPA Science Inventory

Measurements were made relating to the behavior of water-vapor plumes from forced-draft cooling towers and from cooling ponds. There were three categories of measurements. (1) Ambient weather data including temperature, humidity, wind speed and wind direction. These measurements ...

169

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

170

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

171

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

172

Characterizing the Vertical Flux of CO2 within the Nocturnal Boundary Layer near a Tall Tower  

NASA Astrophysics Data System (ADS)

Understanding the vertical dispersion of carbon dioxide respired from plants at night is crucial to distinguishing local- to regional-scale transport and continental-scale transport in global carbon budgets. When atmospheric conditions are stable, CO2 will be weakly mixed, and nearby detectors above the surface layer will instead sample CO2 carried from large distances. These conditions often prevail during the nighttime, making that period ideal for continental-scale sampling. On the other hand, during periods of moderate or intermittent nocturnal turbulence, locally-respired CO2 will be transported through the surface layer and produce a signal at the detector. In August 2008, a 329m tall TV tower (33.4058N, 81.834W) in Aiken, South Carolina (the "South Carolina Tower" http://www.esrl.noaa.gov/gmd/ccgg/towers/#sct) was incorporated into the NOAA-Global Monitoring Division's Tall Tower network. This site is located within a region that varies from agricultural, broken forests, suburban, urban and industrial. Emissions from several cities (most notably Augusta, GA) and industrial sites are within 50km of the tower and may contribute disproportionately to the nighttime tower readings. To distinguish local and regional sources, it is necessary to characterize vertical turbulent transport at this site. There are several ways to do this, and we focus on three. First, a mesoscale model was run at high-resolution to recreate the winds and temperature observed during a May 2009 nocturnal tracer release field project conducted in the region surrounding the site. The model data then served as input to a Lagrangian transport model. This was done for two eight-hour periods on successive but different nights: one slightly stable, and the other more stable. The coupled mesoscale/transport model was then validated against the tracer data, and was used to calculate the dispersion properties of the tracer and provide a 3-dimensional picture of the plume. For comparison, we apply two other methods to calculate eddy diffusivity. We calculate it directly using sonic anemometer and fast-response CO2 flux and concentration data from the tall tower. The fast response data (10Hz) allows for the explicit calculation of the turbulent transport and, along with the vertical gradient, provide an estimate of the diffusivity. As a third method, the eddy diffusivity can also be calculated by an empirical method that uses as input the turbulent properties measured at the tower. We select one such method and compare the results to the other two estimates.

Werth, D. W.; Buckley, R.; Kurzeja, R.; Zhang, G.; Parker, M.; Duarte, H.; Leclerc, M.

2012-12-01

173

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

174

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....

175

Drop Tower Workshop  

NASA Technical Reports Server (NTRS)

Ground based microgravity facilities are an important proving ground for space experiments, ground-based research and space hardware risk mitigation. An overview of existing platforms will be discussed with an emphasis on drop tower capabilities. The potential for extension to partial gravity conditions will be discussed. Input will be solicited from attendees for their potential to use drop towers in the future and the need for enhanced capabilities (e.g. partial gravity)

Urban, David

2013-01-01

176

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,

177

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.

Lori Perkins

2005-04-11

178

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

179

Control of large wind turbine generators connected to utility networks  

NASA Technical Reports Server (NTRS)

This is an investigation of the control requirements for variable pitch wind turbine generators connected to electric power systems. The requirements include operation in very small as well as very large power systems. Control systems are developed for wind turbines with synchronous, induction, and doubly fed generators. Simulation results are presented. It is shown how wind turbines and power system controls can be integrated. A clear distinction is made between fast control of turbine torque, which is a peculiarity of wind turbines, and slow control of electric power, which is a traditional power system requirement.

Hinrichsen, E. N.

1983-01-01

180

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

181

Lower tropospheric horizontal wind over Indonesia: A comparison of wind profiler network observations with global reanalyses  

NASA Astrophysics Data System (ADS)

Horizontal wind data over Indonesia obtained by global reanalyses were compared with wind-profiling radar (WPR) observations in Indonesia at Kototabang (100.32°E, 0.20°S), Pontianak (109.37°E, 0.00°S), Manado (124.92°E, 1.55°N), and Biak (136.10°E, 1.18°S). The global-reanalysis data were 850- and 700-hPa horizontal winds for 2007 and 2008. These data were obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis (R1), the NCEP-Department of Energy (DOE) Atmospheric Model Intercomparison Project (AMIP-II) Reanalysis (R2), the Japan Meteorological Agency Climate Data Assimilation System (JCDAS), the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis-interim (ERA-Interim). All the four reanalyses showed good agreement with the WPR zonal and meridional wind data (correlation coefficient >0.7 in most cases). Of the four reanalyses, ERA-Interim had the highest correlation coefficient with the WPR winds in both zonal (correlation coefficient 0.89) and meridional (0.77) components. It can be explained that ERA-Interim used four-dimensional variational analysis (4D-var) for data assimilation, whereas the other reanalyses used three-dimensional variational analysis (3D-var). The zonal winds of the four reanalyses had smaller (78-87%) amplitudes than did the WPR winds. Further comparison of the zonal winds between the global reanalyses and operational radiosondes indicated that global-reanalysis zonal winds with smaller amplitudes are common in and around Indonesia.

Tabata, Yoshikazu; Hashiguchi, Hiroyuki; Yamamoto, Masayuki K.; Yamamoto, Mamoru; Yamanaka, Manabu D.; Mori, Shuichi; Syamsudin, Fadli; Manik, Timbul

2011-06-01

182

Technical Status Report for US Wind Farmers Network  

SciTech Connect

The theme of the work in this quarter was community-based wind and locally owned wind projects. The work Windustry has done is just beginning to touch the heart of the matter for a hugely interested audience of rural landowners and rural communities. We revised and published a Windustry Newsletter on two farmer owned wind projects called Minwind I and Minwind II. This article was largely researched and written last quarter but the principal individuals that organized the wind projects didn't want any more farmers calling them up than they already had, so they urged us to put a hold on the article or not publish it. This presented a unique problem for Windustry. Up to this point, we had not dealt with generating too much attention for a wind energy project. The story of a group of farmers and individuals pooling their resources for two locally owned commercial-scale wind projects is very compelling and the organizers of the projects were getting a great deal of attention from other farmers that want more details on the project. However, the organizers committed a large amount of their own resources toward the set up of this project which took many hours with their legal counsel and they did not have the capacity or the desire to provide answers for all the other farmers and individuals who were requesting information. Windustry worked with the business entity and did not publish the newsletter until we resolved some of the problems with the high level of interest in this project. Windustry resolved to address this issue by creating a custom track in the state and regional wind energy conference held in Minneapolis, November 21-22, 2002. There were a few sessions in the Landowner and Citizen Workshops track that were specifically created to talk about the ''how-to's for rural landowners to put together their own projects. Also, the conference's Community-Based Wind track addressed what makes a good project and what moneylenders are looking for when they evaluate wind projects. All of this contributed to the general knowledge base for other farmers to understand what it takes to put together their own wind energy enterprise. In a limited way, Windustry is beginning to define, differentiate and explore new types of wind energy business models. A good initial step is defining community-based wind as projects that are publicly owned--by a municipality, a rural electric coop, a county, or public entity like a school system, or hospital or jail. Ultimately, this work will lead to new materials on wind energy business models for rural landowners and communities.

Daniels, Lisa

2003-02-19

183

Wind power forecasting using fuzzy neural networks enhanced with on-line prediction risk assessment  

Microsoft Academic Search

The paper presents an advanced wind forecasting system that uses on-line SCADA measurements, as well as numerical weather predictions (NWP) as input, to predict the power production of wind parks 48 hours ahead. The prediction system integrates models based on adaptive fuzzy-neural networks configured either for short-term (1-10 hours) or long-term (1-48 hours) forecasting. The paper presents detailed one-year evaluation

P. Pinson; G. N. Kariniotakis

2003-01-01

184

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

185

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

186

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

187

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

188

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

189

THE TOWER HOUSE, LOOKING WEST. The tower house provided a ...  

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

THE TOWER HOUSE, LOOKING WEST. The tower house provided a water tank on the second floor that gravity fed water to the Kineth house and farm buildings. The one-story addition to the west of the tower provided workshop space. The hog shed is seen on the left of the image and the concrete foundation of the upright silo is in the foreground on the right. - Kineth Farm, Tower House, 19162 State Route 20, Coupeville, Island County, WA

190

A Towering Achievement  

NSDL National Science Digital Library

In this experience, learners use the internet to research physical details about Chihuly's Fireworks of Glass "Tower" and "Ceiling" and consider the decisions Chihuly had to make as he was planning the sculpture. As part of the activity, learners practice their measuring skills to estimate the height of Chihuly's "Tower." Learners also consider the roles and responsibilities of team members and other workers and why teamwork is important in constructing a large sculpture. This activity is featured on pp.45-48 of the "Fireworks of Glass: The Art of Dale Chihuly" unit of study for grades 3-5.

2014-05-28

191

Cooling Towers Make Money  

E-print Network

F during an ambient wet bulb temperature of 7] OF could not be met The SuperCellular film fill, style] 3] 62 Illustration 3 was selected by the consultant because of its previous highly satisfactory service in sewage treatment trickling filter... in cooling towers for this type of heat rejection application and water quality. The test and performance data was entered into the cooling tower consultant's computer bank, and the results indicated that six feet of the SuperCellular 13] -62 would...

Burger, R.

192

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

193

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

194

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

195

Cooling Towers, Energy Conservation Strategies  

E-print Network

Cooling towers, because of their seeming simplicity, are usually orphans of the facilities operation. We are all aware that cooling towers are the step-children of the chemical process plant, electric power generating station, and refrigeration...

Burger, R.

1983-01-01

196

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

197

Optimization of a wind-power fuel-cell hybrid system in an autonomous electrical network environment  

Microsoft Academic Search

Stability considerations associated with intermittency prevent high wind energy penetration in small electrical networks. The case of the islands of the Aegean is presented. [Ntziachristos L, Kouridis C, Samaras Z, Pattas K. A wind-power fuel-cell hybrid system study on the non-interconnected Aegean islands grid. Renewable Energy 2005;30(10):1471–1487] proposed a wind turbine(WT)–fuel-cell hybrid as a means to store wind energy and

Emmanuel Kasseris; Zissis Samaras; Dimitrios Zafeiris

2007-01-01

198

Tower Investigation and the Egg  

NSDL National Science Digital Library

Towers have been a part of developed society for centuries, serving a variety of purposes, from watch towers to modern cell towers. In this activity, student groups design and build three types of towers (guyed or cable-supported, free-standing or self-standing, and monopole), engineering them to meet the requirements that they hold an egg one foot high for 15 seconds.

Center for Engineering Educational Outreach,

199

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

200

Solar thermal power towers  

Microsoft Academic Search

The solar thermal central receiver technology, known as solar power towers, is rapidly evolving to a state of near-term energy availability for electrical power generation and industrial process heat applications. The systems consist of field arrays of heliostat reflectors, a central receiver boiler, short term thermal storage devices, and either turbine-generators or heat exchangers. Fluid temperatures up to 550 C

FRANK KREITH; RICHARD T. MEYER

1984-01-01

201

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

202

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...

203

Deployable tensegrity towers  

Microsoft Academic Search

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

Jean-Paul Pinaud

2005-01-01

204

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

205

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

206

Remote Survey of the Leaning Tower of Pisa by Interferometric Sensing  

Microsoft Academic Search

The Leaning Tower of Pisa, one of the world-famous architectural marvels of Italian heritage, needs continuous surveying to assess its stability. In this letter, remote-sensing equipment recently developed by the authors, based on the principle of microwave radar interferometry, has been experimented to measure the frequency response of the Tower without requiring any contact with its structure. Wind and human

Carlo Atzeni; Alberto Bicci; Devis Dei; Matteo Fratini; Massimiliano Pieraccini

2010-01-01

207

Remote Survey of the Leaning Tower of Pisa by Interferometric Sensing  

Microsoft Academic Search

9 any contact with its structure. Wind and human traffic were used 10 as natural excitation sources, allowing the natural frequencies 11 of the first vibration mode of the Tower to be measured in the 12 north-south and in the west-east directions. Modal shapes of 13 the Tower vibrations were also obtained from data acquired by 14 the radar. 15

Carlo Atzeni; Alberto Bicci; Devis Dei; Matteo Fratini; Massimiliano Pieraccini

2009-01-01

208

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

209

Synchronization of the DOE/NASA 100-kilowatt wind turbine generator with a large utility network  

NASA Technical Reports Server (NTRS)

The DOE/NASA 100 kilowatt wind turbine generator system was synchronized with a large utility network. The system equipments and procedures associated with the synchronization process were described. Time history traces of typical synchronizations were presented indicating that power and current transients resulting from the synchronizing procedure are limited to acceptable magnitudes.

Gilbert, L. J.

1977-01-01

210

Dynamic Modeling and Control of DFIG-Based Wind Turbines Under Unbalanced Network Conditions  

Microsoft Academic Search

This paper presents an analysis and control design of a doubly-fed induction generator (DFIG)-based wind generation system operating under unbalanced network conditions. A DFIG system model in the positive and negative synchronous reference frames is presented. Variations of stator active and reactive powers and generator torque are fully defined in the presence of negative sequence voltage and current. Alternative DFIG

Lie Xu; Yi Wang

2007-01-01

211

A Control Methodology for DFIG Type Wind Turbines Connected to Distribution Networks  

E-print Network

A Control Methodology for DFIG Type Wind Turbines Connected to Distribution Networks N. K. Roy, H.roy.h.pota.md.mahmud)@adfa.edu.au Ahstract-This paper proposes a decentralised controller design for doubly-fed induction generators (DFIGs in operating conditions. Index Terms-distributed generation (DG), DFIG, H= norm, linear quadratic Gaussian (LQG

Pota, Himanshu Roy

212

Improved Direct Power Control of a DFIG-Based Wind Turbine During Network Unbalance  

Microsoft Academic Search

This paper proposes an improved coordinate direct power control (DPC) strategy for the doubly fed induction generator (DFIG) and the grid side converter (GSC) of a wind power generation system under unbalanced network conditions. Two improved DPC schemes for the DFIG and the GSC are presented, respectively. The DPC for DFIG is to eliminate the torque and stator reactive power

Peng Zhou; Yikang He; Dan Sun

2009-01-01

213

The Leaning Tower of Pisa  

NSDL National Science Digital Library

The official site of the Leaning Tower of Pisa offers users a comprehensive tour of this historic landmark with 6,400 images and two QTVR films. In addition to the exhaustive photographic tour, which illuminates almost every conceivable detail of the Tower's eight floors (help on navigating the photos is available), the site includes a nice history of the Tower from 1173 to the present, and a fourteen-part exhibit on the building's construction and efforts to conserve the Tower. Simply put, this is THE site for anyone interested in the Leaning Tower of Pisa. Naturally, the site is also available in Italian.

214

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

215

Ris National Laboratory Wind Energy Department  

E-print Network

at the National Test Site for wind turbines at Høvsøre (Denmark) and at a 250 m high TV tower at Hamburg (Germany) present first-order closure models of the wind profile in neutral conditions based on a length scale

216

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

217

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

218

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

219

Wind Generation on Winnebago Tribal Lands  

Microsoft Academic Search

The Winnebago Wind Energy Study evaluated facility-scale, community-scale and commercial-scale wind development on Winnebago Tribal lands in northeastern Nebraska. The Winnebago Tribe of Nebraska has been pursuing wind development in various forms for nearly ten years. Wind monitoring utilizing loaned met towers from NREL took place during two different periods. From April 2001 to April 2002, a 20-meter met tower

2009-01-01

220

An experimental 100 kilowatt wind turbine generator  

NASA Technical Reports Server (NTRS)

Experimental generator consists of two blades mounted on 100 foot tower, driving transmission train and electric generator mounted on top of tower. Machine generates 100 kW of electricity at wind speeds from 18 to 60 miles per hour. Yaw control mechanism automatically orients machine into wind.

Thomas, R. L.; Puthoff, R. L.; Savino, J. M.; Johnson, W. R.

1975-01-01

221

Tornado type wind turbines  

DOEpatents

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, Cheng-Ting (Ames, IA)

1984-01-01

222

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

223

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.

2012-08-03

224

An Analysis of Peak Wind Speed Data from Collocated Mechanical and Ultrasonic Anemometers  

NASA Technical Reports Server (NTRS)

This study focuses on a comparison of peak wind speeds reported by mechanical and ultrasonic anemometers at Cape Canaveral Air Force Station and Kennedy Space Center (CCAFS/KSC) on the east central coast of Florida and Vandenberg Air Force Base (VAFB) on the central coast of California. The legacy mechanical wind instruments on CCAFS/KSC and VAFB weather towers are being changed from propeller-and-vane (CCAFS/KSC) and cup-and-vane (VAFB) sensors to ultrasonic sensors under the Range Standardization and Automation (RSA) program. The wind tower networks on KSC/CCAFS and VAFB have 41 and 27 towers, respectively. Launch Weather Officers, forecasters, and Range Safety analysts at both locations need to understand the performance of the new wind sensors for a myriad of reasons that include weather warnings, watches, advisories, special ground processing operations, launch pad exposure forecasts, user Launch Commit Criteria (LCC) forecasts and evaluations, and toxic dispersion support. The Legacy sensors measure wind speed and direction mechanically. The ultrasonic RSA sensors have no moving parts. Ultrasonic sensors were originally developed to measure very light winds (Lewis and Dover 2004). The technology has evolved and now ultrasonic sensors provide reliable wind data over a broad range of wind speeds. However, because ultrasonic sensors respond more quickly than mechanical sensors to rapid fluctuations in speed, characteristic of gusty wind conditions, comparisons of data from the two sensor types have shown differences in the statistics of peak wind speeds (Lewis and Dover 2004). The 45th Weather Squadron (45 WS) and the 30 WS requested the Applied Meteorology Unit (AMU) to compare data from RSA and Legacy sensors to determine if there are significant differences in peak wind speed information from the two systems.

Short, David A.; Wells, Leonard A.; Merceret, Francis J.; Roeder, William P.

2005-01-01

225

Application of Network Planning to Teaching Wind-Surfing  

ERIC Educational Resources Information Center

Study aim: To determine the effects of network planning on teaching untrained subjects windsurfing. Material and methods: Untrained physical education students (n = 390), aged 19-23 years, took part in the study while staying on a summer camp. They were randomly assigned into two groups: experimental (n = 216) and control (n = 174). Two methods of…

Zybko, Przemyslaw; Jaczynowski, Lech

2008-01-01

226

Assessment of Error in Synoptic-Scale Diagnostics Derived from Wind Profiler and Radiosonde Network Data  

NASA Technical Reports Server (NTRS)

A topic of current practical interest is the accurate characterization of the synoptic-scale atmospheric state from wind profiler and radiosonde network observations. We have examined several related and commonly applied objective analysis techniques for performing this characterization and considered their associated level of uncertainty both from a theoretical and a practical standpoint. A case study is presented where two wind profiler triangles with nearly identical centroids and no common vertices produced strikingly different results during a 43-h period. We conclude that the uncertainty in objectively analyzed quantities can easily be as large as the expected synoptic-scale signal. In order to quantify the statistical precision of the algorithms, we conducted a realistic observing system simulation experiment using output from a mesoscale model. A simple parameterization for estimating the uncertainty in horizontal gradient quantities in terms of known errors in the objectively analyzed wind components and temperature is developed from these results.

Mace, Gerald G.; Ackerman, Thomas P.

1996-01-01

227

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

228

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

229

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

230

Ride-Through Analysis of Doubly Fed Induction Wind-Power Generator Under Unsymmetrical Network Disturbance  

Microsoft Academic Search

This paper presents a ride-through simulation study of a 2-MW wind-power doubly fed induction generator (DFIG) under a short-term unsymmetrical network disturbance. The DFIG is represented by an analytical two-axis model with constant lumped parameters and by a finite element method (FEM)-based model. The model of the DFIG is coupled with the model of the active crowbar protected and direct

Slavomir Seman; Jouko Niiranen; Antero Arkkio

2006-01-01

231

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

232

Dynamic Responses and Vibration Control of the Transmission Tower-Line System: A State-of-the-Art Review  

PubMed Central

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

233

Solar energy collection by the tower system  

NASA Astrophysics Data System (ADS)

Solar energy collecting tests were carried out under Japan's Sunshine Project, as part of the solar thermal electric power system. The total mirror area of the heliostats was increased by a factor of three to 300 sq m, making the dimensional ratio between the tower height and field diameter equivalent to that of the pilot plant, as well as achieving a similar heat flux magnitude as the pilot plant. The absorbing efficiency of the No. 4 receiver was studied and proven to be inferior to the No. 7 receiver, with its improved wind shield cavity, reducing reflection losses at higher wind velocities. The difference in convection heat losses between the two receivers in the solar energy collecting apparatus did not, however, directly correspond to the difference between them measured in the pilot plant. Thus, a heat loss test was applied to the No. 7 receiver, and fluctuations in the measured values of absorbing efficiencies were shown to be due to fluctuations of convection heat loss. Future plans include the design of external receivers suitable for low towers, with a lighter weight and a greater compactness for minimum heat loss potential.

Taguchi, T.; Takemoto, M.

1981-01-01

234

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

235

Archaeoastronomy: the Newport Tower  

NASA Astrophysics Data System (ADS)

The Newport Tower is a masonry structure of fieldstone about 28 feet high and 22 feet in diameter located near the top of a hill overlooking the harbor in Newport, Rhode Island. In essence it is a cylinder with Romanesque arches resting on eight pillars. The cylinder has three major openings as well as four smaller ones. On the inside there are eight indentations for beams on a first floor and four for a second,. In addition there are seven niches and a fireplace on the inside. A careful photogrammetric survey of the tower done by the Technical University of Denmark for the Danish National Museum provided data for the calculation of declinations, azimuths and altitudes associated with possible pairs of features. Numerous alignments involving the Sun and Moon indicate an emphasis on determining the location of the nodes of the Moon's orbit. Accurate determination of true north by observing Polaris at upper culmination is evident. Possible observations of Sirius are indicated. These results provide strong evidence that astronomy was involved in the design and use of this intriguing structure first mentioned in Governor Arnold's will in 1677. Further study is clearly warranted. This paper was published in the New England Antiquities Research Association Journal, p. 44, 1994

Penhallow, William

1997-07-01

236

Direct drive wind turbine  

DOEpatents

A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

2006-10-10

237

Direct drive wind turbine  

DOEpatents

A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

2007-02-27

238

Direct drive wind turbine  

DOEpatents

A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

Bywaters, Garrett Lee; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

2006-09-19

239

Direct drive wind turbine  

DOEpatents

A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

Bywaters, Garrett; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

2006-07-11

240

Hurricane Bonnie wind flow characteristics  

Microsoft Academic Search

The Wind Engineering Mobile Instrumented Tower Experiment (WEMITE), the first successful field experiment that placed a reinforced, self-powered, instrumented tower directly in the path of several hurricanes, successfully gathered high-resolution wind speed data from within Hurricane Bonnie as it made landfall near Cape Fear, North Carolina, on 26 August 1998, at 5:00 PM. This data is used to inspect the

John Lee Schroeder

1999-01-01

241

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...

242

The Leaning Tower of Pisa  

Microsoft Academic Search

THE photograph of the ``Leaning'' Tower of Pisa in NATURE of August 4 shows clearly that the top tier is not square with the rest. From a rough alignment with the edge of a postcard, the photograph appears as if the tower was of the order of 25 mm.\\/metre out of plumb when the top tier was put on presumably

Edward G. Brown

1910-01-01

243

The Leaning Tower of Pisa  

Microsoft Academic Search

THIS famous tower will doubtless always be a question, like the man in the iron mask and other historical mysteries. Most architects, however, will be very slow to believe that it would have been built intentionally leaning on the general grounds that, however adventurous the architect, the clients would not have stood it. The analogy of the leaning towers of

Arthur T. Bolton

1910-01-01

244

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.

Lee Krystek

245

Measured and calculated characteristics of wind turbine noise  

Microsoft Academic Search

The results of an analytical and experimental investigation of wind turbine noise are presented. Noise calculations indicate that for configurations with the rotor downwind of the support tower, the primary source of noise is the rapid change in rotor loadings which occurs as the rotor passes through the tower wake. Noise measurements are presented for solid and truss type tower

G. C. Greene

1981-01-01

246

Winding for the wind  

NASA Technical Reports Server (NTRS)

The mechanical properties and construction of epoxy-impregnated fiber-glass blades for wind turbines are discussed, along with descriptions of blades for the Mod 0A and Mod 5A WECS and design goals for a 4 kW WECS. Multicell structure combined with transverse filament tape winding reduces labor and material costs, while placing a high percentage of 0 deg fibers spanwise in the blades yields improved strength and elastic properties. The longitudinal, transverse, and shear modulus are shown to resist stresses exceeding the 50 lb/sq ft requirements, with constant stress resistance expected until fatigue failure is approached. Regression analysis indicates a fatigue life of 400 million operating cycles. The small WECS under prototype development features composite blades, nacelle, and tower. Rated at 5.7 kW in a 15 mph wind, the machine operates over a speed range of 9-53.9 mph and is expected to produce 16,200 kWh annually in a 10 mph average wind measured at 30 ft.

Weingart, O.

1981-01-01

247

Winding for the wind  

NASA Astrophysics Data System (ADS)

The mechanical properties and construction of epoxy-impregnated fiber-glass blades for wind turbines are discussed, along with descriptions of blades for the Mod 0A and Mod 5A WECS and design goals for a 4 kW WECS. Multicell structure combined with transverse filament tape winding reduces labor and material costs, while placing a high percentage of 0 deg fibers spanwise in the blades yields improved strength and elastic properties. The longitudinal, transverse, and shear modulus are shown to resist stresses exceeding the 50 lb/sq ft requirements, with constant stress resistance expected until fatigue failure is approached. Regression analysis indicates a fatigue life of 400 million operating cycles. The small WECS under prototype development features composite blades, nacelle, and tower. Rated at 5.7 kW in a 15 mph wind, the machine operates over a speed range of 9-53.9 mph and is expected to produce 16,200 kWh annually in a 10 mph average wind measured at 30 ft.

Weingart, O.

248

Solar thermal and wind energy power source  

SciTech Connect

A transparent panel enclosed tower provides a confined space for solar heating air. An upright wind turbine, mounted on the tower top, communicates with the tower enclosed space. As the solar heated air expands and becomes lighter it is displaced by cooler atmospheric air at the bottom of the tower creating a turbine driving thermal updraft in combination with wind energy driving the turbine. The turbine includes an axial drive shaft driving a gear train in turn driving an electric generator, or the like.

Argo, W.H.

1980-09-23

249

Fluvial network analysis on Titan: Evidence for subsurface structures and west-to-east wind flow, southwestern Xanadu  

E-print Network

Fluvial network analysis on Titan: Evidence for subsurface structures and west-to-east wind flow; published 25 November 2009. [1] Data of Titan's surface from the Cassini-Huygens mission show inferred, indicating that a variety of factors control fluvial drainage on Titan. Drainage network patterns

Perfect, Ed

250

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.

251

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.

252

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

253

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

254

OPTIMAL MANAGEMENT OF A WIND\\/CAES POWER PLANT BY MEANS OF NEURAL NETWORK WIND SPEED FORECAST  

Microsoft Academic Search

Some of the major limitations of renewable energy sources are represented by their low power density and intermittent nature, largely depending upon local site and unpredictable weather conditions. These problems concur to increase the unit costs of wind power, so limiting their diffusion. By coupling storage systems with a wind farm, some of the major limitations of wind power, such

I. Arsie; V. Marano; M. Moran; G. Rizzo; G. Savino

255

A study of wind variability in the lower troposphere through power spectrum analysis at mesoscale frequencies  

E-print Network

observation site is also located in Yucca Flat about ten statute miles south-southeast of Bren tower. The terrain between the two observation sites slopes gently upward from the RABAL area toward Bren tower and, during good visibility conditions, the base... operated by the Atomic Energy Commission and Weather Bureau, called Bren tower, provided the tower wind observations. The Bren tower is located in a high mountain valley called Yucca Flat. Yucca Plat is part of the Atomic Energy Commission's Nevada Test...

Cornett, John Sheldon

1966-01-01

256

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

257

CN Tower Lightning Current Derivative Heidler Model Analysis and Transmission  

Microsoft Academic Search

The lightning current data collected at the CN Tower can be used for calibrating the Lightning Detection Network (LDN) systems. They can also be used in the modification of existing models and the creation of new ones used for the conversion of the lightning current to electromagnetic and electric propagated fields. The measured lightning current derivative signals at the CN

Ouarda Nedjah; Ali M. Hussein; Sridhar Krishnan; Reza Sotudeh

2008-01-01

258

Analysis and design of guyed transmission towers - case study in Kuwait  

NASA Astrophysics Data System (ADS)

Guyed towers are special nonlinear structures requiring special techniques for analysis and design. The various aspects of geometric nonlinearity are discussed and the energy search method is explained, which is an algorithm believed to be suitable for the analysis of guyed towers. A two-dimensional example tower is investigated which demonstrates the effect of prebuckling displacements on the resulting critical wind load. A three-dimensional 600-m guyed tower case study is also analysed and designed using ANSYS and STAAD-III computer packages. Certain modelling assumption techniques are introduced in order to be able to use the two packages effectively for the analysis and design of guyed towers. The effects of accidental guy rupture and temperature variation have been studied as well.

El-Ghazaly, H. A.; Al-Khaiat, H. A.

1995-05-01

259

You're a What?: Tower Technician  

ERIC Educational Resources Information Center

In this article, the author talks about the role and functions of a tower technician. A tower technician climbs up the face of telecommunications towers to remove, install, test, maintain, and repair a variety of equipment--from antennas to light bulbs. Tower technicians also build shelters and radiofrequency shields for electronic equipment, lay…

Vilorio, Dennis

2012-01-01

260

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

261

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

262

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....

263

Cooling Tower Inspection with Scuba  

E-print Network

A serious problem of scale and other solid material settling in heat transfer equipment was threatening to shut down our ethylene plant. All evidence pointed to the cooling tower as the source of the contamination. Visual inspection of the cooling...

Brenner, W.

1982-01-01

264

Cooling Towers, Energy Conservation Machines  

E-print Network

Cooling towers, in all too many industrial plants, are often the neglected units of the process chain which are hidden bonanzas for energy conservation and dollar savings. By lowering the entire systems temperature by the use of colder water...

Burger, R.

1980-01-01

265

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

266

Cooling towers and evaporative condensers.  

PubMed

By 31 October 1978 there had been four confirmed instances where the Legionnaires' disease bacterium had been isolated from water samples taken from cooling towers or evaporative condensers located near the site of an epidemic of Legionnaires' disease. These devices are widely used to reject unwanted heat into the atmosphere and vary greatly in size and configuration. However, the operation of all towers and condensers depends on intimate contact between the circulating water and ambient air. Airborne contaminants in the vicinity of these devices are likely to be absorbed to some degree by the circulating water. The airstream leaving a cooling tower is saturated with water vapor and may also contain a relatively minute portion of the circulating water in the form of fine droplets known as drift. It is common practice to bleed a small portion of the circulating water, including all contaminants, from the tower into a storm sewer, sanitary sewer, or even a nearby body of water. PMID:434654

Miller, R P

1979-04-01

267

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

268

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

269

Improving Process Cooling Tower Eddiciency  

E-print Network

?Filtration ?Multimedia filtration-sand filters ?Depth of bed filtration ?High turnover rates ?Low cost for the flow rate ?Designed for location and dirt load ?Can be used with sweeper systems ESL-IE-13-05-08 Proceedings of the Thrity-Fifth Industrial...-24, 2013 14 Improving Cooling Tower Efficiency Sweeper systems ?Installed in the tower basin ?Prevents the build up of basin deposits ?Virtually eliminates the bacteria growth in the basin ?Legionella bacteria ?Improves the filter efficiency...

Turpish, W.

2013-01-01

270

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

271

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

272

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

273

How new technology developments will lower wind energy costs  

Microsoft Academic Search

Wind Power is a clean and renewable energy technology that is generated, most commonly through the use of a three-bladed wind turbine mounted on a tall tower (80 m - 100 m). Although wind power is most commonly generated by larger, utility scale wind turbines (1.5 MW - 3 MW in size), smaller capacity (< 500 kW) wind turbines have

D. L. Hoffman; T. S. Molinski

2009-01-01

274

Laboratory-scale experiments on wind turbine nacelle movement estimation  

Microsoft Academic Search

The effect of nacelle motion should be considered when calculating the wind speed relative to the wind turbine structure, which is essential in wind turbine control and performance testing. A Kalman filter approach is applied to estimate the nacelle motion of a wind turbine. Information from several accelerometers and strain gauges which are installed on the wind turbine tower is

Yoonsu Nam; Tai Jun Yoon

2009-01-01

275

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

276

A fiber optic wind vane: A conceptual view  

SciTech Connect

The use of tall towers for the normal operation of meteorological instrumentation is ideal for ensuring that representative measurements are obtained relative to the nearby terrain. Tall towers also expose instrumentation to unwanted environmental side-effects such as lightning surges. The proximity of many industrial observation sites for meteorological towers also introduces unwanted problems including radio frequency interference (RFI) from radio, television, or microwave transmitters, explosive environments, and electrical power cabling. Typical meteorological instrumentation systems incorporate protective mechanisms such as grounding networks, surge protectors and electrical shielding to combat electrical problems. Still, even with elaborate protective systems, damages to instrumentation and a loss of valid data can occur which often results in extended outages. The use of fiber optic technology in meteorological instrumentation holds great promise to eliminate many of the problems associated with monitoring on tall towers. A fiber optic sensor would be impervious to lightning surges and all forms of RFI. The sensor would provide a high signal to noise ratio output since little or no electrical interference would be involved in data transmission. A longer field life for mechanical devices such as a wind vane would be realized since all physical contact points, such as those found in a potentiometer, would be eliminated. Therefore, the precision, resolution, linearity, starting threshold and accuracy could be dramatically improved without the hindrance of moving parts.

Parker, M.J. [Westinghouse Savannah River Co., Aiken, SC (United States); Heaverly, M. [Met One Instruments, Inc., Grants Pass, OR (United States)

1996-07-01

277

Multi-objective optimization of solar tower power plants  

E-print Network

Multi-objective optimization of solar tower power plants Pascal Richter Center for Computational · Optimization of solar tower power plants 1/20 #12;Introduction ­ Solar tower power plants Solar tower PS10 (11 of the solar tower Pascal Richter · Optimization of solar tower power plants 2/20 #12;Model of solar tower

Ábrahám, Erika

278

Mapping carbon flux uncertainty and selecting optimal locations for future flux towers in the Great Plains  

USGS Publications Warehouse

Flux tower networks (e. g., AmeriFlux, Agriflux) provide continuous observations of ecosystem exchanges of carbon (e. g., net ecosystem exchange), water vapor (e. g., evapotranspiration), and energy between terrestrial ecosystems and the atmosphere. The long-term time series of flux tower data are essential for studying and understanding terrestrial carbon cycles, ecosystem services, and climate changes. Currently, there are 13 flux towers located within the Great Plains (GP). The towers are sparsely distributed and do not adequately represent the varieties of vegetation cover types, climate conditions, and geophysical and biophysical conditions in the GP. This study assessed how well the available flux towers represent the environmental conditions or "ecological envelopes" across the GP and identified optimal locations for future flux towers in the GP. Regression-based remote sensing and weather-driven net ecosystem production (NEP) models derived from different extrapolation ranges (10 and 50%) were used to identify areas where ecological conditions were poorly represented by the flux tower sites and years previously used for mapping grassland fluxes. The optimal lands suitable for future flux towers within the GP were mapped. Results from this study provide information to optimize the usefulness of future flux towers in the GP and serve as a proxy for the uncertainty of the NEP map.

Gu, Y.; Howard, D.M.; Wylie, B.K.; Zhang, L.

2012-01-01

279

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

280

Wind-Driven Wireless Networked System of Mobile Sensors for Mars Exploration  

NASA Technical Reports Server (NTRS)

A revolutionary way is proposed of studying the surface of Mars using a wind-driven network of mobile sensors: GOWON. GOWON would be a scalable, self-powered and autonomous distributed system that could allow in situ mapping of a wide range of environmental phenomena in a much larger portion of the surface of Mars compared to earlier missions. It could improve the possibility of finding rare phenomena such as "blueberries' or bio-signatures and mapping their occurrence, through random wind-driven search. It would explore difficult terrains that were beyond the reach of previous missions, such as regions with very steep slopes and cluttered surfaces. GOWON has a potentially long life span, as individual elements can be added to the array periodically. It could potentially provide a cost-effective solution for mapping wide areas of Martian terrain, enabling leaving a long-lasting sensing and searching infrastructure on the surface of Mars. The system proposed here addresses this opportunity using technology advances in a distributed system of wind-driven sensors, referred to as Moballs.

Davoodi, Faranak; Murphy, Neil

2013-01-01

281

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

282

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

283

Data Quality Assessment Methods for the Eastern Range 915 MHz Wind Profiler Network  

NASA Technical Reports Server (NTRS)

The Eastern Range installed a network of five 915 MHz Doppler Radar Wind Profilers with Radio Acoustic Sounding Systems in the Cape Canaveral Air Station/Kennedy Space Center area to provide three-dimensional wind speed and direction and virtual temperature estimates in the boundary layer. The Applied Meteorology Unit, staffed by ENSCO, Inc., was tasked by the 45th Weather Squadron, the Spaceflight Meteorology Group, and the National Weather Service in Melbourne, Florida to investigate methods which will help forecasters assess profiler network data quality when developing forecasts and warnings for critical ground, launch and landing operations. Four routines were evaluated in this study: a consensus time period check a precipitation contamination check, a median filter, and the Weber-Wuertz (WW) algorithm. No routine was able to effectively flag suspect data when used by itself. Therefore, the routines were used in different combinations. An evaluation of all possible combinations revealed two that provided the best results. The precipitation contamination and consensus time routines were used in both combinations. The median filter or WW was used as the final routine in the combinations to flag all other suspect data points.

Lambert, Winifred C.; Taylor, Gregory E.

1998-01-01

284

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

285

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

286

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

287

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

288

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

289

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

290

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

291

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

292

arnaud.vergnol@hei.fr, jonathan.sprooten@hei.fr. Optimal network congestion management using wind farms  

E-print Network

is the increased use of renewable energy for the power generation. However, the integration of such a production management in power systems as long as generation, transmission capacities are well known. Other congestion network reliability. KEYWORDS Congestion management; Wind farm; Power Transfer Distribution Factors (PTDF

Boyer, Edmond

293

Thin film sensor network for condition assessment of wind turbine blades  

NASA Astrophysics Data System (ADS)

Existing sensing solutions facilitating continuous condition assessment of wind turbine blades are limited by a lack of scalability and clear link signal-to-prognosis. With recent advances in conducting polymers, it is now possible to deploy networks of thin film sensors over large areas, enabling low cost sensing of large-scale systems. Here, we propose to use a novel sensing skin consisting of a network of soft elastomeric capacitors (SECs). Each SEC acts as a surface strain gage transducing local strain into measurable changes in capacitance. Using surface strain data facilitates the extraction of physics-based features from the signals that can be used to conduct condition assessment. We investigate the performance of an SEC network at detecting damages. Diffusion maps are constructed from the time series data, and changes in point-wise diffusion distances evaluated to determine the presence of damage. Results are benchmarked against time-series data produced from off-the-shelf resistive strain gauges. This paper presents data from a preliminary study. Results show that the SECs are promising, but the capability to perform damage detection is currently reduced by the presence of parasitic noise in the signal.

Laflamme, Simon; Saleem, Hussam; Venkatesh, Chinde; Vaidya, Umesh; Sarkar, Partha; Sauder, Heather

2014-03-01

294

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

295

Congenital onychogryphosis: Leaning Tower nail.  

PubMed

A 45-year-old man presented with a thickened and raised nail of his left fifth finger since birth. He was otherwise healthy. On examination, the nail of the left little finger was markedly thickened, hyperkeratotic, and situated at an angle of approximately 45 degrees to the long axis of the distal phalanx. There was prominent subungual hyperkeratosis. A diagnosis of congenital onychogryphosis of the little finger of idiopathic nature was considered. Visual analogy to the leaning tower of Pisa encouraged us to describe it as congenital leaning tower nail. PMID:22136865

Nath, Amiya Kumar; Udayashankar, Carounanidy

2011-01-01

296

Dynamic response of guyed towers  

E-print Network

guyed towers. A parametric study was conducted using eigen analysis to determine the effects of consistent mass, geometric stiffness and P-Delta gravity loads. Time domain solutions were obtained by direct integration for motion due to regular Stokes... near the center of the tower. In the present model, the pile foundation is replaced by a simple pinned connection at the sea floor. The dynamic response can be calculated from the equation of motion for a multi-degree of freedom system: [)4] {x...

Gillcrist, Mark Christopher

1984-01-01

297

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

298

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

299

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

300

Cooling Tower Fan Control for Energy Efficiency  

Microsoft Academic Search

This article evaluates the economics of alternative cooling tower capacity control methods. Annual fan electrical energy requirements are calculated for towers with single-speed, two-speed, and variable-speed fans. Fan energy requirements are determined counter-flow and cross-flow towers designed for low initial cost and for energy efficiency. Effectiveness-NTU equations are solved to predict cooling tower performance with the fan running at various

Malcolm R. Stout Jr; James W. Leach

2002-01-01

301

Scaling wind characteristics for designing small and large wind turbines  

Microsoft Academic Search

Since rotationally sampled wind speed spectra are required to explain the turbulence experienced by rotating wind-turbine blades, methods of estimating the shape and magnitude of the rotationally sampled wind-speed spectra for different sizes of turbines have been developed. The primary model used in this paper, called STRS-2, is an empirical one that processes turbulence measurements from a single meteorologial tower

J. R. Connell; R. L. George

1983-01-01

302

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

303

Long-term observations of meteor winds by the SuperDARN HF radar network  

NASA Astrophysics Data System (ADS)

The HF Super Dual Auroral Radar Network (SuperDARN) radars detect a category of backscatter that is due to meteor trails in the mesosphere. The motion of the neutral atmosphere can be inferred and applied to the study of atmospheric tides and planetary waves. The current configurations of longitudinal radar chains in the northern and southern hemispheres have accumulated mesospheric wind measurements continuously since the last solar cycle maximum while the archives of some of the radars span more than a solar cycle. We have analyzed the occurrence of mesospheric tides, planetary wave, and gravity wave activity in the meteor wind data over long periods at several radar stations in both hemispheres. Understanding the behavior of planetary waves and tides is not only crucial to characterizing mesopause variability but also transport in the mesosphere and lower thermosphere. in the mesosphere and lower thermosphere. We examine the seasonal and inter-annual variations of the diurnal, semidiurnal and terdiurnal tides, and planetary waves. We find connections to the quasi-biennial oscillation and to sudden stratospheric warming (SSW) events. We present examples of intensified planetary wave activity that occurred during SSWs. Additionally, we examine the variability in tidal and planetary wave activity over the past solar cycle and correlations with lower atmospheric phenomena and other datasets.

Talaat, Elsayed; Ruohoniemi, J. Michael; McCubbin, Elizabeth; Azeem, S. M. Irfan; Greenwald, Raymond

2012-07-01

304

DISPERSING WLTURE ROOSTS ON COMMUNICATION TOWERS  

Microsoft Academic Search

Communication towers provide attractive roost sites for Black (Coragyps atratus) and Turkey vultures (Cathartes aura). The birds' roosting activity creates problems, however, for tower operators, nearby businesses, and adjacent homeowners. To alleviate these problems, at six sites in northern Florida we evaluated the effectiveness of suspending vulture carcasses or taxidermic effigies from towers to disperse vulture roosts. In each case,

MICHAEL L. AVERY; JOHN S. HUMPHREY; EPIC A. TILLMAN; KIMBERLY O. PHARES; JANE E. HATCHER

305

Asbestos in cooling-tower waters  

Microsoft Academic Search

Fill material in natural- or mechanical-draft cooling towers can be manufactured from a variety of materials, including asbestos cement or asbestos paper. To aid in the environmental impact assessment of cooling towers containing these asbestos types of fill, information on these materials was obtained from cooling-tower vendors and users. Samples of makeup, basin, and blowdown waters at a number of

B. A. G

1977-01-01

306

RBF neural network based PI pitch controller for a class of 5-MW wind turbines using particle swarm optimization algorithm.  

PubMed

In order to control the pitch angle of blades in wind turbines, commonly the proportional and integral (PI) controller due to its simplicity and industrial usability is employed. The neural networks and evolutionary algorithms are tools that provide a suitable ground to determine the optimal PI gains. In this paper, a radial basis function (RBF) neural network based PI controller is proposed for collective pitch control (CPC) of a 5-MW wind turbine. In order to provide an optimal dataset to train the RBF neural network, particle swarm optimization (PSO) evolutionary algorithm is used. The proposed method does not need the complexities, nonlinearities and uncertainties of the system under control. The simulation results show that the proposed controller has satisfactory performance. PMID:22738782

Poultangari, Iman; Shahnazi, Reza; Sheikhan, Mansour

2012-09-01

307

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 ...

308

The solar towers of Chankillo  

E-print Network

An ancient solar observatory is composed by thirteen towers lined on a hill of a coastal desert of Peru. This is the Chankillo observatory. Here we discuss it, showing some simulations of the local sun direction. An analysis of the behaviour of shadows is also proposed.

Sparavigna, Amelia Carolina

2012-01-01

309

Towers and Bridges Civil Engineering  

E-print Network

worksheet for guidance). Materials 1. Balsa wood, popsicle sticks, or toothpicks 2. Glue #12;3. Computers structural components have they seen that make structures stronger (trusses, joints, etc.) Explain or tower crusher, use a block of wood that will sit on the structure, hooks that are distributed across

Provancher, William

310

An integrated modeling method for wind turbines  

NASA Astrophysics Data System (ADS)

To study the interaction of the electrical, mechanical, and aerodynamic aspects of a wind turbine, a detailed model that considers all these aspects must be used. A drawback of many studies in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical model, or vice versa. Hence the interactions between electrical and mechanical aspects of wind turbine operation are not accurately taken into account. In this research, it will be shown that a combination of different simulation packages, namely TurbSim, FAST, and Simulink can be used to model the aerodynamic, mechanical, and electrical aspects of a wind turbine in detail. In this thesis, after a review of some wind turbine concepts and software tools, a simulation structure is proposed for studying wind turbines that integrates the mechanical and electrical components of a wind energy conversion device. Based on the simulation structure, a comprehensive model for a three-bladed variable speed wind turbine with doubly-fed induction generator is developed. Using the model, the impact of a voltage sag on the wind turbine tower vibration is investigated under various operating conditions such as power system short circuit level, mechanical parameters, and wind turbine operating conditions. It is shown how an electrical disturbance can cause more sustainable tower vibrations under high speed and turbulent wind conditions, which may disrupt the operation of pitch control system. A similar simulation structure is used to model a two-bladed fixed speed wind turbine with an induction generator. An extension of the concept is introduced by adding a diesel generator system. The model is utilized to study the impact of the aeroelastic aspects of wind turbine (i.e. tower shadow, wind shears, yaw error, turbulence, and mechanical vibrations) on the power quality of a stand-alone wind-diesel system. Furthermore, an IEEE standard flickermeter model is implemented in a Simulink environment to study the flicker contribution of the wind turbine in the wind-diesel system. By using a new wind power plant representation method, a large wind farm (consisting of 96 fixed speed wind turbines) is modelled to study the power quality of wind power system. The flicker contribution of wind farm is also studied with different wind turbine numbers, using the flickermeter model. Keywords. Simulink, FAST, TurbSim, AreoDyn, wind energy, doubly-fed induction generator, variable speed wind turbine, voltage sag, tower vibration, power quality, flicker, fixed speed wind turbine, wind shear, tower shadow, and yaw error.

Fadaeinedjad, Roohollah

311

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

312

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

313

Alternative methods of estimating hub-height wind speed for small wind turbine performance evaluation  

Microsoft Academic Search

Current industry standards for evaluating wind turbine power performance require erecting a meteorological mast on site to obtain reference measurements of hub-height wind speed. New considerations for small wind turbines (SWTs) offer the alternative of using an anemometer extending from a lower elevation on the turbine tower. In either case, SWT owners face questions and impracticalities when applying this standard

Brett Ziter

2010-01-01

314

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

315

Curve Singularities and Monster / Semple Towers  

E-print Network

In earlier work, we introduced the `Monster tower', a tower of fibrations associated to planar curves. We constructed an algorithm for classifying its points with respect to the equivalence relation generated by the action of the contact pseudogroup on the tower. Here, we construct the analogous tower for curves in $n$-space. (This tower is known as the Semple Bundle in Algebraic Geometry.) The pseudo-group of diffeomorphisms of $n$-space acts on each level of the extended tower. We take initial steps toward classifying points of this extended Monster tower under this pseudogroup action. Arnol'd's list of stable simple curve singularities plays a central role in these initial steps. We end with a list of open problems.

Castro, Alex L

2009-01-01

316

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

317

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

318

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

319

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...

320

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

321

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

322

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

323

Real-time simulation of BLDC-based wind turbine emulator using RT-LAB  

Microsoft Academic Search

A novel wind turbine emulator (WTE) based on a torque controlled Brushless DC (BLDC) motor is presented, which can emulate the steady-state and dynamic characteristics of an actual wind turbine. Variable wind speeds, turbine inertia and torque oscillation caused by tower shadow and wind shear are all considered in the construction of the actual wind turbine model and the torque

Honghao Guo; Bo Zhou; Jichen Li; Fangshun Cheng; Le Zhang

2009-01-01

324

Long-term wind speed and power forecasting using local recurrent neural network models  

Microsoft Academic Search

This paper deals with the problem of long-term wind speed and power forecasting based on meteorological information. Hourly forecasts up to 72-h ahead are produced for a wind park on the Greek island of Crete. As inputs our models use the numerical forecasts of wind speed and direction provided by atmospheric modeling system SKIRON for four nearby positions up to

Thanasis G. Barbounis; John B. Theocharis; Minas C. Alexiadis; Petros S. Dokopoulos

2006-01-01

325

NON-DIVERGENT WIND ANALYSIS ALGORITHM FOR THE ST. LOUIS RAPS (REGIONAL AIR POLLUTION STUDY) NETWORK  

EPA Science Inventory

An objective wind analysis algorithm capable of producing non-divergent wind fields at up to ten levels in the atmospheric boundary layer for St. Louis, Missouri is described. Wind data collected during the St. Louis Regional Air Pollution Study (RAPS) and averaged over 15-minute...

326

24 m meteorological tower data report period: January through December, 1996  

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. This report presents results of the monitoring for January--December, 1996, providing: a status of the measurement systems 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.; Egami, R.; Coulombe, W.; Crow, D.; Cristani, B.; Schmidt, S.

1997-12-01

327

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

328

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

329

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

330

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

331

Salt water cooling tower retrofit experience  

Microsoft Academic Search

This article describes the experience of engineers at Atlantic Electric Co. with a recent cooling tower fill retrofit at the company's B.L. England Station, Unit 3. Note that this tower is unique. It is the first natural draft salt water tower to be built in the United States. Unit 3's closed-loop saltwater cooling system features a double condenser and two

Rittenhouse

1994-01-01

332

Optimal Cell Towers Distribution by using Spatial Mining and Geographic Information System  

E-print Network

The appearance of wireless communication is dramatically changing our life. Mobile telecommunications emerged as a technological marvel allowing for access to personal and other services, devices, computation and communication, in any place and at any time through effortless plug and play. Setting up wireless mobile networks often requires: Frequency Assignment, Communication Protocol selection, Routing schemes selection, and cells towers distributions. This research aims to optimize the cells towers distribution by using spatial mining with Geographic Information System (GIS) as a tool. The distribution optimization could be done by applying the Digital Elevation Model (DEM) on the image of the area which must be covered with two levels of hierarchy. The research will apply the spatial association rules technique on the second level to select the best square in the cell for placing the antenna. From that the proposal will try to minimize the number of installed towers, makes tower's location feasible, and pr...

AL-Hamami, Alaa H

2011-01-01

333

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

334

Optical design of airport control tower cabs.  

PubMed

A study has been made of optical aspects of airport control towers as part of a planned general optimization of control towers by Transport Canada. Problems found were reflections, glare, visual obstructions, identification of distant objects, and excessive solar heat. The study makes recommendations on cab shape, tower height, glazing, shades, sunglasses, binoculars, and internal lighting. Proper choice of cab shape (e.g., 30 degrees window inclination and 12-28 sides) provided effective control of reflections. Some plastic shades werefound to increase the risk of eye damage. Two tower cabs incorporating the recommendations have been built and were found to be satisfactory. PMID:20216882

Carman, P D; Budde, H W

1980-02-15

335

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

336

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

337

COOLING TOWER PUMP HOUSE, TRA606. CONNECTION TO COOLING TOWER. PUMPHOUSE ...  

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

COOLING TOWER PUMP HOUSE, TRA-606. CONNECTION TO COOLING TOWER. PUMP-HOUSE FLOOR PLAN AND FOUNDATION PLANS. LAYOUT OF SIX COOLING TOWER UNITS. BLAW-KNOX 3150-807-2, 12/1950. INL INDEX NO. 53-0607-62-098-100671, REV. 1. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

338

Wind energy.  

PubMed

From its rebirth in the early 1980s, the rate of development of wind energy has been dramatic. Today, other than hydropower, it is the most important of the renewable sources of power. The UK Government and the EU Commission have adopted targets for renewable energy generation of 10 and 12% of consumption, respectively. Much of this, by necessity, must be met by wind energy. The US Department of Energy has set a goal of 6% of electricity supply from wind energy by 2020. For this potential to be fully realized, several aspects, related to public acceptance, and technical issues, related to the expected increase in penetration on the electricity network and the current drive towards larger wind turbines, need to be resolved. Nevertheless, these challenges will be met and wind energy will, very likely, become increasingly important over the next two decades. An overview of the technology is presented. PMID:17272245

Leithead, W E

2007-04-15

339

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

340

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

341

A Microcomputer Model of Crossflow Cooling Tower Performance  

E-print Network

The energy use characteristics of evaporative cooling towers are of interest because, although such towers are widely used in industry, they do require a substantial amount of energy. Evaporative cooling towers are basically large heat exchangers...

Reichelt, G. E; Jones, J. W.

1984-01-01

342

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Collection: Grey Towers Visitor Comment Card AGENCY: Forest Service, USDA. ACTION...0222, ``Grey Towers Visitor Comment Card'' with 0596-0226, ``Forest Service...INFORMATION: Title: Grey Towers Visitor Comment Card. OMB Number: 0596-0222....

2013-03-20

343

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...  

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

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM BELOW, SHOWING VALVE TOWER TO RIGHT. VIEW FACING NORTH - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream, East Range, Wahiawa, Honolulu County, HI

344

Session: What have studies of communications towers suggested regarding the impact of guy wires and lights on birds and bats  

SciTech Connect

This session at the Wind Energy and Birds/Bats workshop consisted of one presentation followed by a discussion/question and answer period. The paper ''Wind turbines and Avian Risk: Lessons from Communications Towers'' was given by Paul Kerlinger. The presenter outlined lessons that have been learned from research on communications (not cell) towers and about the impacts of guy wires and lights on birds and bats and how they could be useful to wind energy developers. The paper also provided specific information about a large 'fatality' event that occurred at the Mountaineer, WC wind energy site in May 2003, and a table of Night Migrant Carcass search findings for various wind sites in the US.

Kerlinger, Paul

2004-09-01

345

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

Microsoft Academic Search

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

Wei Qiao

2008-01-01

346

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 ...

347

Evaluation of central solar tower power plant  

Microsoft Academic Search

A baseline design for heliostat, receiver, tower, and energy transport subsystems for a solar tower power plant has been defined down to the major component level. Preliminary manufacturing plans have been prepared for component fabrication, assembly, and installation. Capital costs have been estimated for the baseline design. The major cost element, other than the power plant, is the heliostat and

C. R. Easton; R. W. Hallet Jr.; S. Gronich; R. L. Gervais

1974-01-01

348

Dry cooling tower with water augmentation  

Microsoft Academic Search

An air cooling tower system is disclosed for condensing exhaust steam in power plants, that has water cooling augmentation to maintain the plant cooling capacity during high atmospheric temperature periods. The cooling tower includes a plurality of banks of brazed aluminum plate and fin type heat exchangers arranged in inverted ''v'' shaped sets. These heat exchangers cool ammonia used as

R. G. Ireland; V. N. Tramontini

1981-01-01

349

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.

350

Energy conservation strategies, the ignored cooling towers  

SciTech Connect

Because of their apparent lack of sophistication, cooling towers are usually considered orphans of the facilities operation. Historically, cooling towers have been neglected in refrigeration air conditioning systems, electric power generating stations, manufacturing plants, and chemical process plants. Operators are aware of the importance of their sophisticated equipment but, they take the apparently simple cooling towers and cold water returning for granted, Since the box looks sturdy and the fans are rotating, the operators think all is well and ignore the quality of water coming off the tower. A cooling tower is purchased for Design Conditions of performance which are specified. Design Conditions relate to the volume of circulating water (GPM), hot water temperature (HWT), cold water temperature (CWT) discharge, and wet bulb temperature (WBT). The WBT consisting of ambient temperature and relative humidity. After the tower is on line and the CWT becomes inadequate, many engineers look to solutions other than the obvious. All cooling towers are purchased to function at 100% of capability in accordance with Design Condition. In the real world of on-stream utilization, the level of operation is lower. It can be deficient as much as 30% due to a variety of reasons which are not necessarily due to the failure of the performance of the tower.

Burger, R.

1997-06-01

351

Repair and completion of damaged cooling tower  

Microsoft Academic Search

This paper reports on a large hyperbolic cooling tower, under construction and nearly completed, struck by a falling tower crane during a tornado. Damage occurred at the upper edge where a V-shaped notch was gouged. Also, considerable cracking beneath the notch was observed. The extent of the damage was documented by precision survey techniques and visual inspection. A comprehensive analytical

P. L. Gould; O. C. Guedelhoefer

1989-01-01

352

Numerical simulation of air-cooling tower  

NASA Astrophysics Data System (ADS)

A mathematic model for packed air-cooling tower thermodynamic calculation is set up in this paper on the basis of fundamental heat and mass transfer equations. Based on the Double Film theory, direct equation-solving method is used to simulate air-cooling tower, and variation of parameters is taken to analyze the data and results of the program.

Hao, Lijuan; Li, Huanzhi; Sun, Zhaohu; Tong, Lige

2003-08-01

353

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

354

Carbon Nanotube Tower-Based Supercapacitor  

NASA Technical Reports Server (NTRS)

A supercapacitor system, including (i) first and second, spaced apart planar collectors, (ii) first and second arrays of multi-wall carbon nanotube (MWCNT) towers or single wall carbon nanotube (SWCNT) towers, serving as electrodes, that extend between the first and second collectors where the nanotube towers are grown directly on the collector surfaces without deposition of a catalyst and without deposition of a binder material on the collector surfaces, and (iii) a porous separator module having a transverse area that is substantially the same as the transverse area of at least one electrode, where (iv) at least one nanotube tower is functionalized to permit or encourage the tower to behave as a hydrophilic structure, with increased surface wettability.

Meyyappan, Meyya (Inventor)

2012-01-01

355

1. VIEW, LOOKING EAST, FROM UNION STATION, INTERLOCKING TOWER AT ...  

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

1. VIEW, LOOKING EAST, FROM UNION STATION, INTERLOCKING TOWER AT RIGHT - Promenade Street Interlocking Tower, Promenade Street between Union Station & East Side Tunnel Viaduct, Providence, Providence County, RI

356

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

357

Measured and calculated characteristics of wind turbine noise  

NASA Technical Reports Server (NTRS)

The results of an analytical and experimental investigation of wind turbine noise are presented. Noise calculations indicate that for configurations with the rotor downwind of the support tower, the primary source of noise is the rapid change in rotor loadings which occurs as the rotor passes through the tower wake. Noise measurements are presented for solid and truss type tower models with both upwind and downwind rotors. Upwind rotor configurations are shown to be significantly quieter than downwind configurations. The model data suggest that averaged noise measurements and noise calculations based on averaged tower wake characteristics may not accurately represent the impulsive noise characteristics of downwind rotor configurations.

Greene, G. C.

1981-01-01

358

Local vibration of transmission line towers due to flood flow. Technical report  

SciTech Connect

Local vibration of transmission line tower due to flood affects the lattices close to ground level, the lattices being slender. This is specially the case with broad based tangent towers for single conductor lines, since the stresses in the lattices are nominal and these have to be designed on the consideration of upper limit of slenderness ratio. Sustained flood flow can cause dynamic stresses resulting in yielding of the lattices ultimately leading to failure of the tower itself. Provision of intermediate supports for the lattices at suitable locations can bring down the amplitude of vibration and hence dynamic stresses. Interference with the vortex shedding by provision of wire winding or strakes, are also suitable steps to keep down the high dynamic stress due to flood flow.

Not Available

1982-05-01

359

Forecasting of wind speed using wavelets analysis and cascade-correlation neural networks  

E-print Network

and the impact of climate change on environment and health. Renewable energy effectively uses natural resources of electricity generation because wind is a clean, indigenous and inexhaustible energy resource that can generate enough electricity to power a lot of homes and businesses [1]. France enjoys an abundant wind potential

Paris-Sud XI, Université de

360

Control of DFIG-based wind generation for power network support  

Microsoft Academic Search

This paper addresses the design and implementation of a novel control scheme for a doubly fed induction generator (DFIG), of the type employed with wind turbines, to provide support to power system operation. It is shown that this controller provides a DFIG-based wind farm with operational and control compatibility with conventional power stations, the ability to contribute to voltage support

F. Michael Hughes; Olimpo Anaya-Lara; Nicholas Jenkins; Goran Strbac

2005-01-01

361

Application of ceilometers to retrieve planetary boundary layer height near tall-tower sites  

NASA Astrophysics Data System (ADS)

Tall tower measurement sites can provide continuous records of various climate-relevant atmospheric gases like CO2, CH4, CO, N2O, or SF6 at different altitude levels. With the help of inverse transport models, the results can be used to determine sources and sinks of important greenhouse gases. Several tall tower sites with heights around 300 m have been established in Poland, Germany and France. Depending on the height of the tower and meteorological conditions, the different levels are influenced by air masses on a local to synoptic scale. A critical parameter for the analysis of the data is the planetary boundary layer height (PBL). If the top of the tower is still inside the PBL the measurements at the top level would be mostly influenced by local to regional sources and sinks. If the top is already in the free troposphere the measurements would be influenced by long-range transport. However, the PBL height cannot be derived from the tower measurements alone. Within the preparations for the Integrated Carbon Observing System (ICOS), several methods for determining PBL height near tall tower sites have been evaluated. During a campaign in France in October 2008, lidar systems, radio sondes as well as two different commercial ceilometers (Vaisala CL31 and Jenoptik CHM15k) were run side-by-side. One goal of the campaign was to find out if and how ceilometers could be used to retrieve PBL height operationally and if they should become part of future ICOS network sites.

Biavati, G.; Feist, D. G.; Heimann, M.

2009-04-01

362

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

363

Wind turbine having a direct-drive drivetrain  

DOEpatents

A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

2011-02-22

364

Coupling a Neural Network-Based forward Model and a Bayesian Inversion Approach to Retrieve Wind Field from Spaceborne Polarimetric Radiometers  

PubMed Central

A simulation study to assess the potentiality of sea surface wind vector estimation based on the approximation of the forward model through Neural Networks and on the Bayesian theory of parameter estimation is presented. A polarimetric microwave radiometer has been considered and its observations have been simulated by means of the two scale model. To perform the simulations, the atmospheric and surface parameters have been derived from ECMWF analysis fields. To retrieve wind speed, Minimum Variance (MV) and Maximum Posterior Probability (MAP) criteria have been used while, for wind direction, a Maximum Likelihood (ML) criterion has been exploited. To minimize the cost function of MAP and ML, conventional Gradient Descent method, as well as Simulated Annealing optimization technique, have been employed. Results have shown that the standard deviation of the wind speed retrieval error is approximately 1.1 m/s for the best estimator. As for the wind direction, the standard deviation of the estimation error is less than 13° for wind speeds larger than 6 m/s. For lower wind velocities, the wind direction signal is too weak to ensure reliable retrievals. A method to deal with the non-uniqueness of the wind direction solution has been also developed. A test on a case study has yielded encouraging results.

Pulvirenti, Luca; Pierdicca, Nazzareno; Marzano, Frank S.

2008-01-01

365

Urban Climatology Applied to the Deterioration of the Pisa Leaning Tower, Italy  

NASA Astrophysics Data System (ADS)

Among the peculiarities of the urban climatology, a relevant one concerns the interactions with monuments, which include stone weathering, deposition and removal of airborne pollutants. In order to know more about the case of the Pisa Leaning Tower, Italy, a field survey has been made for one year, measuring the microclimate interacting with the structure, the vertical temperature and humidity profiles, the Tower surface temperature at different locations and the concentration of particles in air. Also more general information was collected studying the meteorological parameters in the area of Pisa. The correlation between rainfalls and wind evidenced that the windborne droplets arrive from preferential directions, determined on the regional scale by the sea shore on the west (sea breeze) and the channelling operated by the valley of the Arno river on the west. The tilting of the Tower gives a natural shield to the southern part, which is hardly washed by rainfall. The complex balance between airborne particulate matter deposition, tower tilting, rainfall washout and surface runoff determines the pattern of the black crusts which disfigure the elegance of this historical building. The land and sea breezes transport air with different moisture content, and the urban heat island accentuates the mid day drop on relative humidity, determining condensation-evaporation cycles in the stone micropores. The urban climatology of Pisa and the interactions with the Leaning Tower are discussed in view of the conservation of this monument.

Camuffo, D.; Sturaro, G.; Valentino, A.

366

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

367

Wind Monitoring Report for Fort Wainwright's Donnelly Training Area  

SciTech Connect

Using the wind data collected at a location in Fort Wainwright’s Donnelly Training Area (DTA) near the Cold Regions Test Center (CRTC) test track, Pacific Northwest National Laboratory (PNNL) estimated the gross and net energy productions that proposed turbine models would have produced exposed to the wind resource measured at the meteorological tower (met tower) location during the year of measurement. Calculations are based on the proposed turbine models’ standard atmospheric conditions power curves, the annual average wind speeds, wind shear estimates, and standard industry assumptions.

Orrell, Alice C.; Dixon, Douglas R.

2011-01-18

368

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

369

Modeling and control of wind-turbine used DFIG under network fault conditions  

Microsoft Academic Search

Doubly-fed induction generator (DFIG) has been widely used in variable-speed constant-frequency (VSCF) wind energy generation system. Vector control is already applied to the DFIG control, which makes the DFIG gain good performance in the wind energy capturing operation. But in the two traditional vector control schemes, the stator magnetizing current is considered invariant in order to simplify the rotor current

He Yikang; Hu Jiabing; Zhao Rende

2005-01-01

370

Multi-objective optimization of solar tower heliostat fields  

E-print Network

Multi-objective optimization of solar tower heliostat fields Pascal Richter, Martin Frank and Erika 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

371

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

372

Optimal control of a regional power microgrid network driven by wind and solar energy  

Microsoft Academic Search

Abst ract - In this paper, a model to support optimal decisions in a network of microgrids is formalized as an original discrete and centralized problem defined here as cooperative network of smart power grids problem. The control variables are the instantaneous flows of power in the network of microgrids, which can be obtained from the solution of a linear

Hanane Dagdougui; Riccardo Minciardi; Ahmed Ouammi; Roberto Sacile

2011-01-01

373

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, and results for different power systems are presented in the form of indices and probability distributions

Bak-Jensen, Birgitte

374

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

375

Pilot scale cooling tower fouled fill treatment: AFCATT (Anti-Fouling Chemical Additive Test Tower)  

SciTech Connect

Polyvinylchloride (PVC) film-type cellular fill is the fill of choice in replacing cement asbestor board fill in existing cooling towers and in new cooling towers because of its high thermal performance, ease of installation, and low initial cost. However, PVC fill has been found to foul quickly with biological and sediment material, significant reducing tower performance and the fill`s useful life. The Anti-Fouling Chemical Additives Test Tower (AFCATT) has been built to study accumulation rates of fouling deposits in corrugated PVC film fill and to study methods of cleaning and preventing the fouling deposits. This small mechanical draft cooling tower is located next to the Unit 4 natural draft cooling tower at Georgia Power Company`s Plant Bowen. The once-through mechanical draft tower receives hot water from the condenser and returns the cold water to the basin of the host tower. The pilot tower is divided into four chambers allowing for three different treatment programs and one control to be run simultaneously. PVC fill packs are suspended from load cells to allow the weight of the fill packs to be measured continuously. Six vendors participated in the summer 1993 test program. Each proposed different methods of cleaning the fouled fill and were given the opportunity to try their proposed method of fill cleaning. The success of each treatment program was determined by its ability to reduce fill pack weight (i.e., reduce fouling).

Newton, M.T.; Noble, R.T.; Philpot, E.F.; Eastis, J.H. [Southern Company Services, Birmingham, AL (United States)

1995-02-01

376

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

377

Software Verification with Towers of Abstractions  

E-print Network

incorporates such towers of abstractions. 1 Introduction Who hasn't used a computer program that crashed this is a pipe dream. They argue that it is literally impossible to rid non-trivial software of all errors

Weide, Bruce W.

378

Cooling Towers--Energy Conservation Strategies  

E-print Network

A cooling water system can be optimized by operating the cooling tower at the highest possible cycles of concentration without risking sealing and fouling of heat exchanger surfaces, tube bundles, refrigeration equipment, overhead condensers...

Matson, J.

379

On thermal performance of seawater cooling towers  

E-print Network

Seawater cooling towers have been used since the 1970s in power generation and other industries, so as to reduce the consumption of freshwater. The salts in seawater are known to create a number of operational problems, ...

Sharqawy, Mostafa H.

380

Using ozone to treat cooling tower water  

SciTech Connect

Ozone is a controversial but promising alternative to chemicals for treating water in cooling towers. A powerful disinfectant, ozone can prevent biofouling of heat exchange surfaces, and may mitigate scale and corrosion. Ozone treatment of cooling towers can cut costs for energy, water, sewage, and regulatory compliance. Ozone treatment is an electrotechnology, but ozone equipment represents only a small electric load. Although ozone has provided excellent results in some cooling tower applications, its effectiveness has not been proven conclusively. Less than 1,000 cooling towers use ozone water treatment in the United States. Acceptance of this technology is increasing, however, as indicated by its use by such large firms as IBM, AT and T, DuPont, and Xerox, and by its adoption by some chemical water treatment suppliers. The energy efficiency implications of ozone treatment are being researched. Southern California Edison found that in some systems, ozone treatment improved chiller efficiency up to 20 percent due to cleaner heat exchange surfaces.

Webster, L.

1995-07-01

381

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...

382

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

383

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

384

Projective preservation : reframing Rudolph's Tower for Boston  

E-print Network

By 2012, the fate of Paul Rudolph's tower in downtown Boston has been in question for years while a vision of a denser city calls for its demolition. Projected development on the site currently argues that to move forward, ...

Turner, Jessica K

2012-01-01

385

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

386

Solar radiation attenuation in solar tower plants  

Microsoft Academic Search

With the advent of the first commercial solar power tower plants with a rated power in the 10–20MW range, scale-up to larger 20–50MW commercial plants is being considered (Lata et al., 2010; Herring, 2009) in the vast arid regions of the sunbelt. In the case of single-tower plants, the heliostat field size grows considerably and the heliostat–receiver slant range distances

Jesús Ballestrín; Aitor Marzo

387

Stability Properties of Magnetic Tower Jets  

E-print Network

Stability properties of ``magnetic tower'' jets propagating in the gravitationally stratified background have been examined by performing three-dimensional magnetohydrodynamic simulations. The current-carrying, Poynting flux-dominated magnetic tower jet, which possesses a highly wound helical magnetic field, is subject to the current-driven instability (CDI). We find that, under general physical conditions including small perturbations in the initial background profiles, the propagating magnetic tower jets develop the non-axisymmetric, $m=1$ kink mode of the CDI. The kink mode grows on the local Alfv\\'en crossing time scale. In addition, two types of kink modes appear in the system. At the central region where external thermal pressure confinement is strong, only the internal kink mode is excited and will grow. A large distance away from the central region where the external thermal pressure becomes low, the external kink mode is observed. As a result, the exterior of magnetic tower jets will be deformed into a large-scale wiggled structure. We also discuss extensively the different physical processes that contribute to the overall stability properties of the magnetic tower jets. Specifically, when the jet propagates in an initially unperturbed background, we find that they can survive the kink mode beyond the point predicted by the well-known Kruskal-Shafranov (K-S) criterion. The stabilization in this case comes mainly from the dynamical relaxation of magnetic twists during the propagation of magnetic towers; the magnetic pitch is reduced and the corresponding K-S critical wavelength becomes longer as the tower jet proceeds. Furthermore, we show that the pressure-driven and Kelvin-Helmholtz instabilities do not occur in the magnetic tower jets.

Masanori Nakamura; Hui Li; Shengtai Li

2006-08-31

388

Energy conservation strategy: The ignored cooling tower  

SciTech Connect

Cooling towers in electric generating plants are orphans ignored by many engineers and operators. The importance of the cooling water is that more energy is required since hotter water reduces product output at greater energy input to overcome resultant high head pressures and high head temperatures. Generating plants, chemical processes and refrigeration loops, that utilize cooling towers, could be superior money makers if better understood. Towers hardly ever break down. As long as the box stands there and appears solid, with fans constantly rotating, there are numerous engineers that think that all is well with the cooling tower, turn their backs on it, and proceed to spend funds on their power generating and process equipment. Conversely, colder water generates better vacuums, equipment runs cooler which saves energy and makes more dollar profit. This presentation will investigate basic cooling tower technology and compare State-of-the-Art retrofit and upgrading to optimize the different types of cooling towers. Actual field operations hands on slides will be presented with detailed statistics of costs, energy savings generated and payback.

Burger, R.

1996-12-31

389

Wind Spires as an Alternative Energy Source  

SciTech Connect

This report discloses the design and development of an innovative wind tower system having an axisymmetric wind deflecting structure with a plurality of symmetrically mounted rooftop size wind turbines near the axisymmetric structure. The purpose of the wind deflecting structure is to increase the ambient wind speed that in turn results in an overall increase in the power capacity of the wind turbines. Two working prototypes were constructed and installed in the summer of 2009 and 2012 respectively. The system installed in the Summer of 2009 has a cylindrical wind deflecting structure, while the tower installed in 2012 has a spiral-shape wind deflecting structure. Each tower has 4 turbines, each rated at 1.65 KW Name-Plate-Rating. Before fabricating the full-size prototypes, computational fluid dynamic (CFD) analyses and scaled-down table-top models were used to predict the performance of the full-scale models. The performance results obtained from the full-size prototypes validated the results obtained from the computational models and those of the scaled-down models. The second prototype (spiral configuration) showed at a wind speed of 11 miles per hour (4.9 m/s) the power output of the system could reach 1,288 watt, when a typical turbine installation, with no wind deflecting structure, could produce only 200 watt by the same turbines at the same wind speed. At a wind speed of 18 miles per hour (8 m/sec), the spiral prototype produces 6,143 watt, while the power generated by the same turbines would be 1,412 watt in the absence of a wind deflecting structure under the same wind speed. Four US patents were allowed, and are in print, as the results of this project (US 7,540,706, US 7,679,209, US 7,845,904, and US 8,002,516).

Majid Rashidi, Ph.D., P.E.

2012-10-30

390

Science and Technical Considerations for Wind Farm Siting  

NSDL National Science Digital Library

This instructional module was created at the 2009 ATEEC Fellows Institute on Wind Power. The following sections are provided: An introduction to wind power classes, Offshore turbine tower foundations, Wind speed lab, Wind shear project, Turbulence and links to supporting resources. The classroom lessons include student worksheets. The entire guide may be downloaded in PDF file format. This resource is free to download. Users must first create a login with ATEEC's website to access the file.

391

Measuring thermospheric winds and temperatures with a tri-static Fabry-Perot interferometer network in Alaska  

NASA Astrophysics Data System (ADS)

For some 35 years Fabry-Perot interferometer (FPI) measurements in the auroral region have been carried out with a single ground-based observatory. The problem with this approach is that the three components of the neutral wind vector within the region observed along the line-of-sight cannot be determined. Only the radial motion of the emitting species of atomic oxygen atoms, O1D, can be determined for any single direction toward the auroral or airglow source region. This poses a problem in studying the polar ion-neutral coupling that takes place in the course of geostrophic adjustment at high latitudes. This process describes the thermospheric response to the changing forcing functions represented by the day-to-night pressure gradient, the Pedersen ion drag imposed upon the neutral atmosphere by the polar ionospheric plasma convection, and the thermospheric Joule and soft-particle heating sources. The balancing of these forcing functions is also influenced by the action of the Coriolis force modifying the flow field at high latitudes. To study these changes during the course of auroral sub-storm activity that enters into the ion-neutral coupling interaction of the thermosphere-ionosphere system, it is of great importance to measure the three components of the neutral wind vector within a common volume. This is especially true for the auroral region where the vertical wind cannot be assumed to be zero during auroral substorm events. Accordingly, a tri-static FPI network will be installed in central Alaska to support the AMISR radar facility, which would measure the thermospheric electric fields in the region of overlap with the common volume observed by the AkFPI network of three FPI observatories. The three FPI instruments will be installed in the three Alaskan locations of Eagle, Ft. Yukon, and Poker Flat, and first results are expected as of October, 2006. The FPI instruments are classified as imaging FPIs, and the sensitivities are expected to be 3-5 ms-1 and 15-20 K for the horizontal thermospheric wind speed and temperature for an integration period of 60 s and an auroral signal of 250 R.

Meriwether, J. W.; Larsen, M. F.; Hedden, R.; Faivre, M.

2006-12-01

392

Improved Control of DFIG Wind Turbines for Operation with Unbalanced Network Voltages  

Microsoft Academic Search

Many wind turbine generators (WTGs) are installed in remote, rural areas, where the power grids are usually weak, characterized by unbalanced voltage conditions. If the voltage unbalance is not taken into account in the control system, it will cause poor power quality and poor operating performance of the WTG systems. This paper proposes a novel control scheme to improve the

Wei Qiao; Ronald G. Harley

2008-01-01

393

Enhanced Control and Operation of DFIG-Based Wind Farms During Network Unbalance  

Microsoft Academic Search

This paper investigates the control and operation of doubly fed induction generator (DFIG)-based wind generation systems under unbalanced voltage conditions. DFIG system behaviors under unbalanced voltage are analyzed and different control targets are discussed. A new rotor current control strategy containing a main controller and an auxiliary controller is proposed. The main controller is implemented in the positive (dq)+ frame

Lie Xu

2008-01-01

394

A Study of the Solar Wind-Magnetosphere Coupling Using Neural Networks  

Microsoft Academic Search

The interaction between solar wind plasma and interplanetary magnetic field (IMF) and Earth's magnetosphere induces geomagnetic activity. Geomagnetic storms can cause many adverse effects on technical systems in space and on the Earth. It is therefore of great significance to accurately predict geomagnetic activity so as to minimize the amount of disruption to these operational systems and to allow them

Jian-Guo Wu; Henrik Lundstedt

1996-01-01

395

A Stochastic Digital Implementation of a Neural Network Controller for Small Wind Turbine Systems  

Microsoft Academic Search

This letter presents a reconfigurable hardware implementation of feed-forward neural networks using stochastic techniques. The design is based on the stochastic computation theory to approximate the nonlinear sigmoid activation functions with reduced digital logic resources. The large parallel neural network structure is then implemented on a reconfigurable field-programmable gate array (FPGA) device with high fault tolerance capability. The method is

Hui Li; Da Zhang; Simon Y. Foo

2006-01-01

396

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

397

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

398

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

399

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

400

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

401

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

402

Wind vanes in the antiquity  

NASA Astrophysics Data System (ADS)

Mesopotamia: An Akkadian tablet, the original of which was incised between about 1800 and 1600 B.C., makes explicit mention of a wind vane. Further three Sumero-Akkadian “dictionaries” have three different names for the single Akkadian name for wind vane. Since the latest period of flourishing of the Sumerian civilization took place between about 2 100 and 2000 B.C., wind vanes must have been in use in ancient Mesopotamia already about 4000 years ago, i.e. about 2000 years before the Chinese and Greeks had wind vanes. The Mesopotamian wind vanes were made of wood. China: It appears from the old Chinese literature that streamers were in use about the 2nd century B.C. in China for wind vanes. Shortly thereafter, a wind vane in the shape of a bird made of bronze is mentioned in the literature. Greece: The wind vane in the shape of a triton that was fixed, according to Vitruvius, to the top of the Tower of Winds at Athens, must have disappeared before A.D. 1436. Roman Empire: According to a passage in Dio Chrysostom's writtings, streamers appear to have been used for wind vanes. What seems to be the first wind vane in the shape of a cock, was erected in the 2nd century A.D. on the top of the mausoleum of the Flavians, in a North African province of the Roman Empire.

Lindgrén, S.; Neumann, J.

1983-06-01

403

Dry vacuum towers have lower operating costs  

SciTech Connect

Operating costs of crude vacuum towers can be reduced by modifying them to dry (no steam injected into the process) operation. Steam savings alone will often justify any heater revisions, tower internals replacement and ejector revisions necessary when converting an existing wet crude vacuum tower to a dry unit. The justification can be enhanced if the internals replaced are high-pressure-drop types such as bubble-cap types, valve types, or sieve trays. The two types of operation (dry vs. wet) are compared in a typical non-lube oil vacuum unit. Tower internals for both the wet and dry operation are assumed to be of lower pressure drop design, needed for dry operation. High pressure drop internals would increase steam requirements in the wet system tower over the relative rates presented. To further simplify the comparison, it is assumed that two gas oils, a heavy vacuum gas oil (HVGO) and a light gas oil (LVGO), are produced and that their distillation ranges are about the same for both wet and dry modes of operation. Schematic representations of typical wet and dry vacuum units are shown. Overall goals and operating conditions are essentially the same in most wet and dry vacuum units. The refiner wishes to maximize cracking unit feed in the form of gas oils and minimize production of resid.

Hendrickson, M.J.

1986-08-01

404

Mycobacteria in Finnish cooling tower waters.  

PubMed

Evaporative cooling towers are water systems used in, e.g., industry and telecommunication to remove excess heat by evaporation of water. Temperatures of cooling waters are usually optimal for mesophilic microbial growth and cooling towers may liberate massive amounts of bacterial aerosols. Outbreaks of legionellosis associated with cooling towers have been known since the 1980's, but occurrences of other potentially pathogenic bacteria in cooling waters are mostly unknown. We examined the occurrence of mycobacteria, which are common bacteria in different water systems and may cause pulmonary and other soft tissue infections, in cooling waters containing different numbers of legionellae. Mycobacteria were isolated from all twelve cooling systems and from 92% of the 24 samples studied. Their numbers in the positive samples varied from 10 to 7.3 × 10(4) cfu/L. The isolated species included M. chelonae/abscessus, M. fortuitum, M. mucogenicum, M. peregrinum, M. intracellulare, M. lentiflavum, M. avium/nebraskense/scrofulaceum and many non-pathogenic species. The numbers of mycobacteria correlated negatively with the numbers of legionellae and the concentration of copper. The results show that cooling towers are suitable environments for potentially pathogenic mycobacteria. Further transmission of mycobacteria from the towers to the environment needs examination. PMID:23937212

Torvinen, Eila; Suomalainen, Sini; Paulin, Lars; Kusnetsov, Jaana

2014-04-01

405

Salt water cooling tower retrofit experience  

SciTech Connect

This article describes the experience of engineers at Atlantic Electric Co. with a recent cooling tower fill retrofit at the company's B.L. England Station, Unit 3. Note that this tower is unique. It is the first natural draft salt water tower to be built in the United States. Unit 3's closed-loop saltwater cooling system features a double condenser and two 50% capacity horizontal circulating water pumps. A natural draft cooling tower rejects heat to the atmosphere through evaporation and sensible heat transfer. The tower is 180 ft in diameter at the base and 208 ft high, and features a counterflow design. It was designed to cool 63,500 gpm of circulating salt water through a range of 26 F with an approach of 19.2 degrees at an ambient wet bulb temperature of 76 F and 60% relative humidity. A drift rate of 0.002% of circulating water flow was specified to avoid excessive salt water carryover.

Rittenhouse, R.C.

1994-06-01

406

Wind speed and direction shears with associated vertical motion during strong surface winds  

NASA Technical Reports Server (NTRS)

Strong surface winds recorded at the NASA 150-Meter Ground Winds Tower facility at Kennedy Space Center, Florida, are analyzed to present occurrences representative of wind shear and vertical motion known to be hazardous to the ascent and descent of conventional aircraft and the Space Shuttle. Graphical (percentage frequency distributions) and mathematical (maximum, mean, standard deviation) descriptions of wind speed and direction shears and associated updrafts and downdrafts are included as functions of six vertical layers and one horizontal distance for twenty 5-second intervals of parameters sampled simultaneously at the rate of ten per second during a period of high surface winds.

Alexander, M. B.; Camp, D. W.

1984-01-01

407

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

408

Establishing a Comprehensive Wind Energy Program  

SciTech Connect

This project was directed at establishing a comprehensive wind energy program in Indiana, including both educational and research components. A graduate/undergraduate course ME-514 - Fundamentals of Wind Energy has been established and offered and an interactive prediction of VAWT performance developed. Vertical axis wind turbines for education and research have been acquired, instrumented and installed on the roof top of a building on the Calumet campus and at West Lafayette (Kepner Lab). Computational Fluid Dynamics (CFD) calculations have been performed to simulate these urban wind environments. Also, modal dynamic testing of the West Lafayette VAWT has been performed and a novel horizontal axis design initiated. The 50-meter meteorological tower data obtained at the Purdue Beck Agricultural Research Center have been analyzed and the Purdue Reconfigurable Micro Wind Farm established and simulations directed at the investigation of wind farm configurations initiated. The virtual wind turbine and wind turbine farm simulation in the Visualization Lab has been initiated.

Fleeter, Sanford [Purdue University

2012-09-30

409

Grid-side converter control of DFIG wind turbines to enhance power quality of distribution network  

Microsoft Academic Search

A doubly fed induction generator wind turbine (DFIG-WT) with FACTS capabilities is presented. It is suggested to make use of the grid-side converter as a shunt active filter in order to support the grid with power factor correction as well as harmonic compensation. A vector control scheme is used to control the grid-side converter with a priority level feature to

E. Tremblay; A. Chandra; P. J. Lagace

2006-01-01

410

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

411

Methods of attenuating wind turbine ac generator output variations  

NASA Technical Reports Server (NTRS)

Wind speed variation, tower blockage and structural and inertial factors produce unsteady torque in wind turbines. Methods for modifying the turbine torque so that steady torque is delivered to the coupled ac generator are discussed. The method that may evolve will be influenced by the power use that develops and the trade-offs of cost, weight and complexity.

Gold, H.

1978-01-01

412

WIND TUNNEL INVESTIGATION OF THE RESPONSE OF A SONIC ANEMOMETER  

EPA Science Inventory

An Applied Technology Inc. (ATI) sonic of the type used by J. C. Kaimal at the Boulder Tower was tested in the large wind tunnel at the U.S. EPA Fluid Modeling Facility. The wind tunnel is approximately 6 ft high, 10 ft wide with a test section bed 60 ft long. The air speed in th...

413

Load reduction of wind turbines using receding horizon control  

Microsoft Academic Search

Large scale wind turbines are lightly damped mechanical structures driven by wind that is constantly fluc- tuating. In this paper, we address the design of a model-based receding horizon control scheme to reduce the structural loads in the transmission system and the tower, as well as provide constant (or at least smooth) power generation. Our controller incorporates two optimization problems:

Mohsen Soltani; Rafael Wisniewski; Per Brath; Stephen Boyd

2011-01-01

414

Wind Turbine Response to Analytic Inflow Vortex Parameters Variation: Preprint  

Microsoft Academic Search

As larger wind turbines are placed on taller towers, rotors frequently operate in atmospheric conditions that support organized, coherent turbulent structures. It is hypothesized that these structures have a detrimental impact on the blade fatigue life experienced by the wind turbine. These structures are extremely difficult to identify with sophisticated anemometry such as ultra-sonic anemometers. In order to ascertain the

M. M. Hand; M. C. Robinson; M. J. Balas

2003-01-01

415

Wind turbine response to parameter variation of analytic inflow vortices  

Microsoft Academic Search

As larger wind turbines are placed on taller towers, rotors frequently operate in atmospheric conditions that support organized, coherent turbulent structures. It is hypothesized that these structures have a detrimental impact on the blade fatigue life experienced by the wind turbine. These structures are extremely difficult to identify with sophisticated anemometry such as ultrasonic anemometers. This study was performed to

M. Maureen Hand; Michael C. Robinson; Mark J. Balas

2006-01-01

416

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

417

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

418

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

419

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

420

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

421

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

422

CUORE-0: The First CUORE Tower  

NASA Astrophysics Data System (ADS)

The CUORE experiment will search for neutrinoless double beta decay of 130Te using TeO2 bolometers arranged in 19 closely packed towers. Before construction of the full CUORE detector, the first CUORE tower, named CUORE-0, is planned to be installed in the cryostat that housed the recently completed CUORICINO experiment. The CUORE-0 experiment will test the detector assembly procedures developed for CUORE. It will also improve on the limit on the neutrinoless double beta decay half-life of 130Te set by CUORICINO. The status of CUORE-0 and expectations for its performance will be presented.

Bryant, Adam

2008-10-01

423

Monitoring a tall tower through radar interferometry: The case of the Collserola tower in Barcelona  

NASA Astrophysics Data System (ADS)

Data acquired through a Real Aperture Radar interferometer aimed at monitoring a tall tower and its guys are here analysed. The acquisition of temporal samples of interferometric phase, corresponding to different parts of the tower, are used to estimate main vibration frequencies and modal shapes of the tower. Guys have been also monitored to verify the possibility to retrieve their tension force using the taut string approximation. The study confirmed the potential of this technique considering also that an analogous monitoring carried out with conventional contact sensors would be unadvisable due to its high costs and the strong electromagnetic noise of this environment.

Luzi, Guido; Crosetto, Michele; Monserrat, Oriol

2014-05-01

424

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

425

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

426

Steam sand dryer in northeast part of sand tower. View ...  

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

Steam sand dryer in northeast part of sand tower. View to northeast - Duluth & Iron Range Rail Road Company Shops, Sand Tower, Southwest of downtown Two Harbors, northwest of Agate Bay, Two Harbors, Lake County, MN

427

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

428

47 CFR 5.109 - Antenna and tower requirements.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 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...

2010-10-01

429

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

430

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,...

431

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...  

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

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM ENTRY. VIEW FACING NORTHWEST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream, East Range, Wahiawa, Honolulu County, HI

432

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

433

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

434

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

435

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

436

View from southwest to northeast of cooling towers for perimeter ...  

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

View from southwest to northeast of cooling towers for perimeter acquisition radar building and PAR power plant - Stanley R. Mickelsen Safeguard Complex, Cooling Tower, In Limited Access Area, between Service Roads D & A, Nekoma, Cavalier County, ND

437

North and west sides of the cooling tower, utility building ...  

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

North and west sides of the cooling tower, utility building (building 2606) is in the background at right - March Air Force Base, Strategic Air Command, Cooling Tower, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

438

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

439

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

440

4. VIEW, LOOKING SOUTHEAST, SHOWING NORTHWEST ELEVATION OF TOWER ND ...  

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

4. VIEW, LOOKING SOUTHEAST, SHOWING NORTHWEST ELEVATION OF TOWER ND SIGNAL BRIDGE No. 6 AND DWARF SIGNAL IN FOREGROUND - South Station Tower No. 1 & Interlocking System, Dewey Square, Boston, Suffolk County, MA

441

1. General view of site looking south, showing tower to ...  

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

1. General view of site looking south, showing tower to east of interlocking. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

442

3. General view showing north elevation of Shell Interlocking Tower ...  

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

3. General view showing north elevation of Shell Interlocking Tower and electric relay station. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

443

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

444

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

445

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

446

26. Evening view of concrete mixing plant, concrete placement tower, ...  

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

26. Evening view of concrete mixing plant, concrete placement tower, cableway tower, power line and derrick. Photographer unknown, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

447

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

448

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

449

1. General view of crossing gate tower, taken in 1916 ...  

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

1. General view of crossing gate tower, taken in 1916 (courtesy of Erie Railroad Company) (photocopy) - Erie Railway, Crossing Gate Tower, West side of Lincoln Street, 100 feet South of Concord Street, Union City, Erie County, PA

450

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

451

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

452

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

453

Large Wind Energy Converter: Growian 3 MW  

NASA Technical Reports Server (NTRS)

The final report on the projected application of larger-scale wind turbine on the northern German coast is summarized. The designs of the tower, machinery housing, rotor, and rotor blades are described accompanied various construction materials are examined. Rotor blade adjustment devices auxiliary and accessory equipment are examined.

Feustel, J. E.; Helm, S.; Koerber, F.

1980-01-01

454

Inspection techniques for wind turbine blades using ultrasound and sound waves  

Microsoft Academic Search

Facing the climate change the use of renewable energies gains in importance. Especially wind energy will play a major role in the power supply in Central Europe. Due to the increasing number of installed wind energy plants, regular inspections are necessary to avoid accidents. Besides the tower and the gear, the wind turbine blades are highly stressed parts. Suitable non-destructive

Anne JUENGERT; Christian U. GROSSE

455

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...

456

Wind Energy Opportunities, Challenges, and Progress Within the Federal Government (Poster)  

SciTech Connect

Wind Powering America (WPA) works with Federal agencies to increase their understanding of wind resources and assessment; facilitate project development activities through Met tower loans, wind data analysis, and technical assistance; and provide advice on RFP development and financing options. This poster provides an overview of WPA's activities with the federal sector.

Robichaud, R.

2009-05-01

457

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

458

AUTOMATED COUNTING of LEGO TOWERS Doron ZEILBERGER 1  

E-print Network

AUTOMATED COUNTING of LEGO TOWERS Doron-dimensional animal, alias polyomino, can be realized in terms of a LEGO* * tower. Suppose that we have an infinite supply of 1 x a (a 1) LEGO pieces. Then every flo* *or of the tower consists of a finite

Zeilberger, Doron

459

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

460

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

461

CONCRETE PAD AND SUSPENSION BRIDGE TOWERS FOR CABLES FORMERLY SUPPORTING ...  

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

CONCRETE PAD AND SUSPENSION BRIDGE TOWERS FOR CABLES FORMERLY SUPPORTING THE SUSPENSION BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE. VIEW FACING NORTHEAST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream, East Range, Wahiawa, Honolulu County, HI

462

Radar tower frequency control and earthquake response analysis  

Microsoft Academic Search

For the sake of avoiding the impact of surrounding buildings on the radar, radar tower is usually high, generally up to 100 meters. As the radar performance reasons, the required fundamental frequency of radar tower should not be less than 1Hz. For such a tall building, how to control the frequency of radar tower is an issue worth studying. Through

Zeyu Wu; Yuhe Li; Fuming Wang; Dongwei Wang

2010-01-01

463

Cooling tower simulation with coal gasification wastewater. Final report  

Microsoft Academic Search

This study was an investigation into the feasibility of utilizing a coal gasification wastewater as makeup to an evaporative cooling tower. A bench scale cooling tower and heat exchanger were constructed and four experimental test runs were performed. Two of the test runs were made with wastewater as the makeup source. The makeup water for the first cooling tower run

L. J. McShea; R. G. Luthy

1984-01-01

464

Crosswind and internal flow characteristics of dry cooling towers  

Microsoft Academic Search

Experiments are described which were performed to determine how the arrangement of heat exchanger bundles at the base of a natural draft dry cooling tower affects the tower's internal flow and its sensitivity to crosswinds. Model towers with heat exchanger bundles represented by gauze screens were used in tests with no crosswinds at high Re numbers and with crosswind effects

C. M. B. Russell; T. V. Jones; D. W. Holder; H. R. McChesney; M. Verlinden

1977-01-01

465

Analysis of modified counter-flow cooling towers  

Microsoft Academic Search

Evaporative air cooling for human comfort and other applications, whenever possible and feasible, is less expensive than conventional air conditioning. A cooling tower is used in the centralised evaporative air cooling system. In the present study, the counter-flow cooling tower is modified to pre-cool the air at the tower inlet, either by the water after the cooling load, or the

M. P. Maiya

1995-01-01

466

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

467

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

468

14. General oblique view of Shell Interlocking Tower, north and ...  

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

14. General oblique view of Shell Interlocking Tower, north and west facades, showing over head catenary tower and bridge at right. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

469

6. Detail of northeast corner of Shell Interlocking Tower, showing ...  

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

6. Detail of northeast corner of Shell Interlocking Tower, showing ornamental east concrete beltcourse and tower shield with bronze numerals. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

470

Humidification tower for humid air gas turbine cycles: Experimental analysis  

Microsoft Academic Search

In the HAT (humid air turbine) cycle, the humidification of compressed air can be provided by a pressurised saturator (i.e. humidification tower or saturation tower), this solution being known to offer several attractive features. This work is focused on an experimental study of a pressurised humidification tower, with structured packing. After a description of the test rig employed to carry

A. Traverso

2010-01-01

471

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.

472

Solar energy collection by the tower system  

Microsoft Academic Search

Solar energy collecting tests were carried out under Japan's Sunshine Project, as part of the solar thermal electric power system. The total mirror area of the heliostats was increased by a factor of three to 300 sq m, making the dimensional ratio between the tower height and field diameter equivalent to that of the pilot plant, as well as achieving

T. Taguchi; M. Takemoto

1981-01-01

473

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...

474

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 ...

475

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...

476

Optimized Pointing Strategies for Solar Tower ACTs  

Microsoft Academic Search

We discuss simulations of novel heliostat pointing configurations designed to improve the angular and energy resolution of a solar tower wavefront-sampling atmospheric Cherenkov telescope. One such configuration will be tested via observations of the Crab Nebula with the STACEE detector in the fall of 2003.

R. A. Scalzo; L. M. Boone; D. Bramel; J. Carson; C. E. Covault; P. Fortin; G. Gaunthier; D. Gingrich; D. Hanna; A. Jarvis; J. Kildea; C. Mueller; R. Mukherjee; R. A. Ong; K. Ragan; D. A. Williams; J. Zweerink

2003-01-01

477

The optics of the solar tower reflector  

Microsoft Academic Search

The concept of the reflective solar tower is based on inverting the path of the solar rays originating from a heliostat field to a solar receiver that can be placed on the ground. This system is based on the property of a reflective quadric surface to reflect each ray oriented to one of its foci to its second focus. Two

Akiba Segal; Michael Epstein

2001-01-01

478

Tower Power: Producing Fuels from Solar Energy  

ERIC Educational Resources Information Center

This article examines the use of power tower technologies for the production of synthetic fuels. This process overcomes the limitations of other processes by using a solar furnace to drive endothermic fuel producing reactions and the resulting fuels serve as a medium for storing solar energy. (BT)

Antal, M. J., Jr.

1976-01-01

479

Untapped Energy Savings from Cooling Towers  

E-print Network

A cooling tower is often an overlooked source of easy energy savings. As long as it's running not much thought is usually given to it, but when numbers are applied to how much a degree of colder water is worth it can become a valuable and ready...

Phelps Jr., P.

2011-01-01

480

Troubleshooting crude vacuum tower overhead ejector systems  

SciTech Connect

Routinely surveying tower overhead vacuum systems can improve performance and product quality. These vacuum systems normally provide reliable and consistent operation. However, process conditions, supplied utilities, corrosion, erosion and fouling all have an impact on ejector system performance. Refinery vacuum distillation towers use ejector systems to maintain tower top pressure and remove overhead gases. However, as with virtually all refinery equipment, performance may be affected by a number of variables. These variables may act independently or concurrently. It is important to understand basic operating principles of vacuum systems and how performance is affected by: utilities, corrosion and erosion, fouling, and process conditions. Reputable vacuum-system suppliers have service engineers that will come to a refinery to survey the system and troubleshoot performance or offer suggestions for improvement. A skilled vacuum-system engineer may be needed to diagnose and remedy system problems. The affect of these variables on performance is discussed. A case history is described of a vacuum system on a crude tower in a South American refinery.

Lines, J.R.; Frens, L.L. (Graham Manufacturing Co., Inc., Batavia, NY (United States))

1995-03-01

481

Computational intelligence and tower defence games  

Microsoft Academic Search

The aim of this paper is to introduce the use of Tower Defence (TD) games in Computational Intelligence (CI) research. We show how TD games can provide an important test-bed for the often under-represented casual games research area. Additionally, the use of CI in the TD games has the potential to create a more interesting, interactive and ongoing game experience

Phillipa Avery; Julian Togelius; Elvis Alistar; Robert Pieter van Leeuwen

2011-01-01

482

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...

483

Modeling Magnetic Tower Jets in the Laboratory  

NASA Astrophysics Data System (ADS)

The twisting of magnetic fields threading an accretion system can lead to the generation on axis of toroidal field loops. As the magnetic pressure increases, the toroidal field inflates, producing a flow. Collimation is due to a background corona, which radially confines this axially growing “magnetic tower”. We investigate the possibility of studying in the laboratory the dynamics, confinement and stability of magnetic tower jets. We present two-dimensional resistive magnetohydrodynamic simulations of radial arrays, which consist of two concentric electrodes connected radially by thin metallic wires. In the laboratory, a radial wire array is driven by a 1 MA current which produces a hot, low density background plasma. During the current discharge a low plasma beta (? < 1), magnetic cavity develops in the background plasma (? is the ratio of thermal to magnetic pressure). This laboratory magnetic tower is driven by the magnetic pressure of the toroidal field and it is surrounded by a shock envelope. On axis, a high density column is produced by the pinch effect. The background plasma has >rsim1, and in the radial direction the magnetic tower is confined mostly by the thermal pressure. In contrast, in the axial direction the pressure rapidly decays and an elongated, well collimated magnetic-jet develops. This is later disrupted by the development of m = 0 instabilities arising in the axial column.

Ciardi, A.; Lebedev, S. V.; Chittenden, J. P.; Ampleford, D. J.; Bland, S. N.; Bott, B. S.; Rapley, J.

2005-07-01

484

The Legacy of the Texas Tower Sniper  

ERIC Educational Resources Information Center

In this article, the author relates the incident that happened at the University of Texas to the tragedy that took place at Virginia Tech. On August 1, 1966, Charles Joseph Whitman ascended the University of Texas Tower, in Austin, and in 96 minutes fired 150 high-powered rounds of ammunition down upon an unsuspecting university family. The…

Lavergne, Gary

2007-01-01

485

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

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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