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1

Modal analysis of wind turbine tower  

Microsoft Academic Search

As the support structure of wind turbine, the tower bears alternating loads of wind when the wind turbine runs. To ensure the reliability of the wind turbine, it's necessary to carry out modal analysis on the tower, and this would prevent the natural frequency of the tower close to the rated speed of wind turbine. In this paper, finite element

Jie Chen; Dongxiang Jiang

2010-01-01

2

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

3

Hydrogen Storage in Wind Turbine Towers  

SciTech Connect

Low-cost hydrogen storage is recognized as a cornerstone of a renewables-hydrogen economy. Modern utility-scale wind turbine towers are typically conical steel structures that, in addition to supporting the rotor, could be used to store hydrogen. This study has three objectives: (1) Identify the paramount considerations associated with using a wind turbine tower for hydrogen storage; (2)Propose and analyze a cost-effective design for a hydrogen-storing tower; and (3) Compare the cost of storage in hydrogen towers to the cost of storage in conventional pressure vessels. The paramount considerations associated with a hydrogen tower are corrosion (in the form of hydrogen embrittlement) and structural failure (through bursting or fatigue life degradation). Although hydrogen embrittlement (HE) requires more research, it does not appear to prohibit the use of turbine towers for hydrogen storage. Furthermore, the structural modifications required to store hydrogen in a tower are not cost prohibitive.

Kottenstette, R.; Cotrell, J.

2003-09-01

4

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

5

Structural Design of Shanghai Tower for Wind Loads  

Microsoft Academic Search

Nearby Jin Mao tower and the World Financial Center, the 632-meter, 121-story mixed-use Shanghai tower will be the tallest super tall tower in the new Lujiazui Finance and Trade Zone of Shanghai. Due to the super tall height, curved façade and spiraling form of the Shanghai tower project, wind is the dominant lateral load and governed many aspects of the

X. Zhaoa; J. M. Ding; H. H. Suna

2011-01-01

6

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

7

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

8

Remote monitoring and nondestructive evaluation of wind turbine towers  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

9

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

Federal Register 2010, 2011, 2012, 2013

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

2013-02-15

10

Wind Turbine Tower Optimization Method Using a Genetic Algorithm  

Microsoft Academic Search

A wind turbine tower optimization program was developed, using a genetic algorithm. This allowed a rational analysis to reduce the mass of turbine tower, by considering, for example, the distributions of diameter and wall thickness, and the positions of flanges and access ports to navigation lights. Both extreme and fatigue loads were calculated, based on wind turbine design requirements and

Shigeo Yoshida

2006-01-01

11

Along-wind response of a wind turbine tower with blade coupling subjected to rotationally sampled wind loading  

Microsoft Academic Search

This paper proposes an approach to investigate the along-wind forced vibration response of a wind turbine tower and rotating blades assembly subjected to rotationally sampled stationary wind loading. The wind turbine assembly consists of three rotating rotor blades connected to the top of a flexible annular tower, constituting a multi-body dynamic entity. The tower and rotating blades are each modelled

P. J. Murtagh; B. Basu; B. M. Broderick

2005-01-01

12

Wind Shear Characteristics at Central Plains Tall Towers (presentation)  

SciTech Connect

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

Schwartz, M.; Elliott, D.

2006-06-05

13

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

14

Wind tunnel test method to study out-of-service tower crane behaviour in storm winds  

Microsoft Academic Search

An experimental method used to study the behaviour of tower cranes in strong winds exposed to the disturbed shear flow induced by the surrounding built environment is proposed. Wind tunnel tests on a tower crane model are described, the tower crane is considered as a rigid body slender structure equipped with a single degree of freedom part: the crane mobile

D. Voisin; G. Grillaud; C. Solliec; A. Beley-Sayettat; J.-L. Berlaud; A. Miton

2004-01-01

15

Wind Shear Characteristics at Central Plains Tall Towers  

SciTech Connect

The object of this study is to analyze wind shear characteristics at tall tower sites in the Central Plains of the United States. The hub heights of modern turbines used for wind farm projects are now 70 meters (m) to 100 m above ground and some advanced turbines under development for deployment during the second half of this decade are rated at 2-5 megawatts of energy generation with rotor diameters near 100 m and hub heights of 100-120 m. These advanced turbines will take advantage of the higher wind speeds aloft to generate more wind energy. Specific knowledge of important wind shear characteristics near and at turbine hub height is needed to optimize turbine design and wind farm layout. Unfortunately, wind speed shear measurements at heights of 80-120 m were virtually nonexistent a few years ago and are still quite uncommon today. The Central Plains is a prime wind energy development region and knowledge about the wind shear characteristics will reduce uncertainty about the resource and enhance wind farm design. Previous analyses of tall tower data (Schwartz and Elliott, 2005) concentrated on data from specific states. The wind energy community has recognized the need to fill the gap of direct wind speed measurements at levels 70 m and higher above the ground. Programs instituted during the last 5 years at the state level and supported by the U.S. Department of Energy's (DOE) State Energy Program initiative have placed anemometers and vanes at several levels on existing tall (70 m+) communication towers. The Central Plains has a fairly high concentration of tall tower sites. The distribution of tall tower sites varies among the states in the Central Plains, because the tall tower program is new and the available state and federal funding to establish tall towers is variable. Our wind resource assessment group at DOE's National Renewable Energy Laboratory (NREL) has obtained much of these necessary measurement data from both individual state sources and regional organizations. Most of the data are available to the public, though data from one tower in Colorado are proprietary. We have begun to analyze important wind climate parameters, including wind shear from the tall towers. A total of 13 tall towers were used for this study. Eleven of the towers had the highest anemometer level between 100 m and 113 m. Two towers had the highest measurement level between 70 m and 85 m above ground. The distribution of the towers among the states is: two sites in Texas and Oklahoma; six sites in Kansas; and one site each in Colorado, South Dakota, and North Dakota. Figure 1 shows the locations and names of the thirteen towers. The wind resource at these sites can be classified as ranging from good-to-excellent. Eight tall tower sites have Class 3 resource, four sites have Class 4 resource, and one has Class 5 resource at 50 m.

Schwartz, M.; Elliott, D.

2006-01-01

16

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

17

Galloping of internally resonant towers subjected to turbulent wind  

NASA Astrophysics Data System (ADS)

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

Zulli, Daniele; Di Egidio, Angelo

2014-09-01

18

Numerical simulation of wind turbine blade-tower interaction  

NASA Astrophysics Data System (ADS)

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

Wang, Qiang; Zhou, Hu; Wan, Decheng

2012-09-01

19

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

20

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

Microsoft Academic Search

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,

R. J. Christie

1982-01-01

21

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

Microsoft Academic Search

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

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

2011-01-01

22

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

Federal Register 2010, 2011, 2012, 2013

...Utility Scale Wind Towers From the Socialist Republic of Vietnam: Preliminary Determination of Sales at Less Than...wind towers'') from the Socialist Republic of Vietnam (``Vietnam'') are being, or are likely to be, sold in...

2012-08-02

23

Performance prediction of a cooling tower using artificial neural network  

Microsoft Academic Search

This paper describes an application of artificial neural networks (ANNs) to predict the performance of a cooling tower under a broad range of operating conditions. In order to gather data for training and testing the proposed ANN model, an experimental counter flow cooling tower was operated at steady state conditions while varying the dry bulb temperature and relative humidity of

M. Hosoz; H. M. Ertunc; H. Bulgurcu

2007-01-01

24

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

25

Wind Speeds as Measured by Cup and Sonic Anemometers and Influenced by Tower Structure  

Microsoft Academic Search

Wind tunnel and field experiments have shown that the fast-response three-component sonic anemometer is a highly accurate wind speed sensor. When sonic anemometers were used as reference sensors for wind speed, slower response cup anemometers were found to consistently overestimate the wind speed. Despite measures taken during a field program in Kansas to minimize tower influence on wind measurements, the

Yutaka Izumi; Morton L. Barad

1970-01-01

26

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

27

Safe fatigue life of steel towers under the action of wind vibrations  

Microsoft Academic Search

The problem of definition of the service life for high-rise steel tower installations is solved, depending on the fatigue damage accumulated in members or sections. This problem is important for towers and most communication systems, wind turbine supports and others, because for this type of structure wind load is regarded as the main load. The analysis of damage in most

M. A. Mikitarenko; A. V. Perelmuter

1998-01-01

28

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

Federal Register 2010, 2011, 2012, 2013

...Utility Scale Wind Towers From the Socialist Republic of Vietnam: Amended Final Determination of Sales at Less Than...wind towers'') from the Socialist Republic of Vietnam (``Vietnam''). In addition, the Department is amending...

2013-02-15

29

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

Federal Register 2010, 2011, 2012, 2013

...Utility Scale Wind Towers From the Socialist Republic of Vietnam: Final Determination of Sales at Less Than Fair Value...wind towers'') from the Socialist Republic of Vietnam (``Vietnam'').\\1\\ Based on the Department's...

2012-12-26

30

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

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

...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

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

33

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.

34

Visual appearance of wind turbine tower at long range measured using imaging system  

NASA Astrophysics Data System (ADS)

Wind turbine towers affect the visual appearance of the landscape, as an example in the touristic woodland of Dalecarlia, and the fear is that the visual impact will be too negative to the important tourist trade. The landscape analysis, developed by municipalities around Lake Siljan, limited expansion of wind power, due to the strong visual impression of wind turbine towers. In order to facilitate the assessment of the visual impact of towers a view, from Tällberg, over the ring of height on the other side of Lake Siljan, has been photographed every ten minutes for a year (34,727 images, about 65% of the possible number during a year). Four towers are possible to see in the photos, three of them have been used in the assessment of visual impression. This contribution presents a method to assess visibility of wind turbine towers from photographs, describing the measuring situation (location and equipment) as well as the analytical method and results of the analysis. The towers are possible to see in about 48% of analyzed images taken during daytime with the used equipment. During the summer (winter) months the towers were apparent in 49% (46%) of the images. At least one red warning light was possible to see on towers in about 66% of the night images. One conclusion of this work is that the method to assess the visibility within digital photographs and translate it into the equivalent of a normal eye can only provide an upper limit for visibility of an object.

Gustafsson, K. Ove S.; Möller, Sebastian

2013-10-01

35

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

36

Safety and serviceability assessment for high-rise tower crane to turbulent winds  

Microsoft Academic Search

Tower cranes are commonly used facilities for the construction of high-rise structures. To ensure their workability, it is\\u000a very important to analyze their response and evaluate their condition under extreme conditions. This paper proposes a general\\u000a scheme for safety and serviceability assessment of high-rise tower crane to turbulent winds based on time domain buffeting\\u000a response analysis. Spatially correlated wind velocity

Zhi Sun; Nin Hou; Haifan Xiang

2009-01-01

37

Wind Climate Analyses for a 61-M Tower in the Southeast  

SciTech Connect

The Savannah River Technology Center's (SRTC) Atmospheric Technologies Group (ATG) has operated nine 61-m tower sites including the Central Climatology (CC) tower which is located near the center of the Savannah River Site (SRS) since 1985. Data from the weather instruments on this tower have provided answers to questions involving risk analyses, dose studies, forecast verifications, and wind/temperature conditions during extreme events and planned tests. Most recently, data from these towers are being used for initial and boundary conditions for computationally intensive numerical simulations using mesoscale forecasting models that are run on a three-hourly basis by ATG for SRS and the surrounding vicinity. We found that a series of wind roses based on relatively short time scales (from two weeks to one hour) were a convenient method to depict the predominant wind speeds and directions at anemometer sites in the Southeast operated by the NWS. That report also revealed some interesting spatial and temporal relationships among thirteen NWS stations in the Carolinas, Georgia, and Florida. Our study here will focus on the CC tower to show changes in the wind speed and direction distributions with height during diurnal and annual cycles. This study will concentrate on mean wind speed and direction statistics.

Weber, A.H.

2003-11-24

38

Hydrogen Storage in Wind Turbine Towers: Cost Analysis and Conceptual Design; Preprint  

SciTech Connect

Low-cost hydrogen storage is recognized as a cornerstone of a renewables-hydrogen economy. Modern utility-scale wind turbine towers are typically conical steel structures that, in addition to supporting the rotor, could be used to store hydrogen. The most cost-effective hydrogen tower design would use substantially all of its volume for hydrogen storage and be designed at its crossover pressure. An 84-m tall hydrogen tower for a 1.5-MW turbine would cost an additional $84,000 (beyond the cost of the conventional tower) and would store 950 kg of hydrogen. The resulting incremental storage cost of $88/kg is approximately 30% of that for conventional pressure vessels.

Kottenstette, R.; Cotrell, J.

2003-09-01

39

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

40

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

41

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

SciTech Connect

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.

1996-09-24

42

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.

43

Recent Results From the NOAA/ESRL GMD Tall Tower Network  

NASA Astrophysics Data System (ADS)

We will present a summary of new results from NOAA Earth System Research Laboratory`s Tall Tower greenhouse gas monitoring network. The tower network is operated by the Global Monitoring Division, which also maintains the global Cooperative Air Sampling network and a network of aircraft profiling sites over North America. Tall tower CO2 mixing ratio measurements are sensitive to upwind fluxes over scales of hundreds of kilometers, and the primary objective of the tower network is to obtain regionally representative carbon flux estimates for the North American continent. Mixing ratios of CO2 and CO are measured semi-continuously at the towers, and the KWKT-TV tower site near Moody, TX has recently also been equipped with sensors to measure radon and O3. Daily flask samples are collected at the KWKT tower and analyzed for CO2, CO, CH4, SF6, N2O, H2, stable isotopes of CO2 and CH4, COS, and a variety of halocarbon and hydrocarbon species. Daily flask sampling will be implemented at all tower sites within the next few years. We have used the Stochastic Time Inverted Lagrangian Transport (STILT) model to investigate upwind influences on the tower observations. CO measurements provide an indicator of polluted air masses, and we will present a summary of the frequency and origin of pollution events observed at the towers. We will present an analysis of the primary factors contributing to observed CO2 variability along with average seasonal and diurnal cycles of CO2 at the tower sites. Tower measurements are being used to evaluate atmospheric transport models in the context of the Transcom Continuous experiment and are an important constraint for CO2 data assimilation systems that produce regional to global carbon flux estimates with up to weekly resolution.

Andrews, A. E.; Tans, P. P.; Peters, W.; Hirsch, A.; Sweeney, C.; Petron, G.; Kofler, J.; Zhao, C.; Masarie, K.; Wofsy, S. C.; Matross, D. M.; Mahadevan, P.; Longo, M.; Gerbig, C.; Lin, J. C.

2006-12-01

44

NASTRAN use for cyclic response and fatigue analysis of wind turbing towers  

NASA Technical Reports Server (NTRS)

A procedure is described which uses NASTRAN coupled with fatigue criteria via a postprocessor to determine the cyclic response and to assess the fatigue resistance (fatigue life) of wind turbine generator towers. The cyclic loads to which the tower may be subjected are entered either in a quasi-static approach though static load subcases (Rigid Format 1) or through the direct dynamic response (Rigid Format 9) features of NASTRAN. The fatigue criteria are applied to NASTRAN output data from either rigid format through an externally written user program embedded in a postprocessor.

Chamis, C. C.; Manos, P.; Sinclair, J. H.; Winemiller, J. R.

1977-01-01

45

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

46

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

E-print Network

physical parameters and results of experiment to measure air flow through a wind tower from internal heat generation. Air density (lb/ft3) 0.07 pxCp (Btu/ft3-F) 0.018 Air gas constant R (ft-lbf/lbm-R) 53.34 Atmospheric pressure (lb/in2) 14... physical parameters and results of experiment to measure air flow through a wind tower from internal heat generation. Air density (lb/ft3) 0.07 pxCp (Btu/ft3-F) 0.018 Air gas constant R (ft-lbf/lbm-R) 53.34 Atmospheric pressure (lb/in2) 14...

Seryak, J.; Kissock, J. K.

2002-01-01

47

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

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

48

WindPACT Rotor Design Study: Hybrid Tower Design; Period of Performance: 29 June 2000 -- 28 February 2004  

SciTech Connect

The cost of a wind turbine tower can represent as much as 20% of the cost of an entire megawatt-scale horizontal axis wind turbine (HAWT) and as much as 10% of the total cost of energy. The tower is a major cost component, and its design is important: Its structural properties are key to the response of the rotor; its height determines the wind regime that the rotor experiences; it allows access to the turbine nacelle and rotor; and it houses components of the electrical connection and the control and protection systems. Most large wind turbines installed in the United States use self-supporting steel tubular towers. The diameter of these tubes is limited by the size that can be transported by road (approximately 4.3 m). The base dimensions of a truss tower are not restrained by this limit, but trusses may require more maintenance. Guyed tube towers have been used, but they represent additional foundation costs and inconvenience. Addressing these limitations may lead to an alternative that avoids the problems. For this reason, the WindPACT Rotor Design Study was modified to include a study of a hybrid tower to determine the technical and economic feasibility of such a design.

Malcolm, D. J.

2004-04-01

49

Comparative study of artificial neural networks and multiple regression analysis for predicting hoisting times of tower cranes  

Microsoft Academic Search

This paper aims to develop a quantitative model for predicting the hoisting times of tower cranes for public housing construction using artificial neural network and multiple regression analysis. Firstly, based on data collected from crane operators and site managers in seven construction sites, the basic factors affecting the hoisting times for tower cranes are identified. Then, artificial neural networks (ANN)

Arthur W. T Leung; C. M Tam; D. K Liu

2001-01-01

50

Comparison of wind pressure measurements on tower-like structure obtained from full-scale observation, wind tunnel test, and the CFD technology  

Microsoft Academic Search

Full-scale measurements, wind tunnel tests and CFD calculations have been carried out on pressure measurements on a tower-like structure. This paper presents the comparison of pressure measurements among these three methods. The mean wind pressure coefficients obtained from the wind tunnel tests are fairly close to those of the full-scale measurements after the reference pressure is taken into consideration. RMS

Morimasa Watakabe; Masamiki Ohashi; Hisashi Okada; Yasuo Okuda; Hitomi Kikitsu; Shinji Ito; Yasuhito Sasaki; Kenji Yasui; Kiyomine Yoshikawa; Masao Tonagi

2002-01-01

51

Research on Fault Diagnosis Method of the Tower Crane Based on RBF Neural Network  

Microsoft Academic Search

As a result of the diversity of the tower crane faults, after the faults occurred, it is difficulty to accurately discriminate the fault type immediately. In this paper, the “clustering” of the RBF neural network effected on the input samples can be used to automatically realize the classification of the failure modes. Accordingly, the faults are diagnosed, and the specific

Xiaoyang Liu; Tingting Xue; Qing Jiang; Jian Li

2010-01-01

52

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

53

Neural Network Expert System in the Application of Tower Fault Diagnosis  

NASA Astrophysics Data System (ADS)

For the corresponding fuzzy relationship between the fault symptoms and the fault causes in the process of tower crane operation, this paper puts forward a kind of rapid new method of fast detection and diagnosis for common fault based on neural network expert system. This paper makes full use of expert system and neural network advantages, and briefly introduces the structure, function, algorithm and realization of the adopted system. Results show that the new algorithm is feasible and can achieve rapid faults diagnosis.

Liu, Xiaoyang; Xia, Zhongwu; Tao, Zhiyong; Zhao, Zhenlian

54

Does the European eddy flux tower network represent the climatic and ecophysiological diversity of Europe?  

NASA Astrophysics Data System (ADS)

In analyzing the increase of greenhouse gas concentration in terrestrial atmosphere, the studies about the role of vegetation in the carbon exchange regulation are relevant. In this respect, a network using the eddy covariance technique to measure CO2 and H2O exchanges between terrestrial ecosystems and atmosphere, has been established. When the network was established, 16 towers all located in forest ecosystems were maintained. In the past 15 years, the network grew and the current Carboeurope-IP monitoring network consists of more than 100 flux towers (www.carboaurope.org) located all over Europe aiming to represent the diversified of geographic regions, climatic and vegetation characteristics (Plant Functional Types). Because the growth of the network was driven by funding and administrative issues rather than scientific needs, we evaluated, in retrospective, the representativeness of the current network based on climatic and ecophysiological characteristics of the sites and the European territory. We used a cluster approach based on the distance matrix of Self Organizing Maps (SOM) (Kohonen 2001), where the SOM was trained with 21 variables describing main meteorological and productivity characteristics and their inter-annual and seasonal variability of the European territory. A separate SOM was trained for each PFT and the representativeness of eddy towers sites has been evaluated on the basis of their positions on the SOM clusters map (i.e. the 21-D variable-space). The main underlying assumption was that the number of clusters within each PFT was similar to the current number of towers. The analysis showed that the current network is representing the European domain quite well in respect to the variables considered, although North-Eastern and South-Eastern climatic and ecosphysiological conditions are poorly sampled for several PFT. The same approach was used to propose a new tower arrangement that maximizes the network representativeness. Further, our results shown that use of data-driven clustering techniques like SOM can contribute to the evaluation of network representativeness with important impact in network design and analysis of model simulations based on the data derived from this monitoring network. Kohonen T (2001) Self-Organizing Maps. Springer-Verlag, Berlin.

Canfora, E.; Papale, D.; Luyssaert, S.; Sulkava, M.

2009-04-01

55

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

56

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

57

Study on Soft-Sensing Model of Tower Crane Load Based on Functional Link Neural Network  

Microsoft Academic Search

The nonlinear relation between the load and the force of sensor in soft-sensing of tower crane load is indicated by force analysis of load limiter. This paper proposes a soft-sensing model based on functional link neural network (FLNN) with the force of sensor as input and the load as output. By adding some high-order terms, the model applies the single-layer

Quanmin Guo; Yin Dang

2009-01-01

58

Atmospheric CO2 and CH4 Measurement Network on Towers in Siberia  

Microsoft Academic Search

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

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

2006-01-01

59

Bird Strikes and Electrocutions at Power Lines, Communication Towers, and Wind Turbines: State of the Art and State of the Science - Next Steps Toward Mitigation1  

Microsoft Academic Search

Migratory birds suffer considerable human-caused mortality from structures built to provide public serv- ices and amenities. Three such entities are increasing nationwide: communication towers, power lines, and wind turbines. Communication towers have been grow- ing at an exponential rate over at least the past 6 years. The U.S. Fish and Wildlife Service is especially con- cerned about growing impacts to

Albert M. Manville

2005-01-01

60

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

61

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

NASA Astrophysics Data System (ADS)

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

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

1982-03-01

62

Report on a wind-energy applications network for Hawaii  

Microsoft Academic Search

A wind energy applications network (WEAN) for Hawaii is proposed to coordinate the various activities in wind conversion. The network includes an infrastructure of people, programs, and governmental agencies working together to solve problems of wind energy conversion with a common goal of securing optimum utilization of Hawaii's wind energy potential. The network concept has a wind energy development objective

D. R. Neill; P. K. Takahashi

1978-01-01

63

Estimating CH4 Emissions in California Using Measurements from a Tower Network  

NASA Astrophysics Data System (ADS)

We estimate regionally resolved methane (CH4) emissions for California using a Bayesian inverse model driven by CH4 mixing ratios measured at a network of five towers across the Central Valley during 2010 - 2011. The method estimates emissions by comparing measurements with transport model predictions of CH4 signals obtained from two 0.1 degree prior emission maps: 1) seasonally varying "California-specific" emission maps, calibrated to State emission totals, and 2) the EDGAR4.2 static global emission map. Atmospheric transport is calculated from particle trajectories and surface footprints using the Weather Research and Forecasting (WRF) and Stochastic Time-Inverted Lagrangian Transport (STILT) models. Results for the 5-tower CARB-CEC-LBNL-NOAA network show that significant reductions in posterior emissions uncertainty are obtained for regions comprising ~ 90% of California's known CH4 emissions, with annually averaged emissions totaling 1.6+/-0.1 and 2.5+/-0.3 times California's inventory for the California-specific and EDGAR4.2 emissions maps, respectively. Assuming these results apply across California, total CH4 emissions account for approximately 8% - 14% of current state total greenhouse gas emissions. The magnitude and uncertainty of emissions from specific regions and source sectors (e.g., crop agriculture, waste management, livestock, and energy activities) are estimated by comparing region and source sector results obtained with the CA-specific and EDGAR4.2 emission maps.

Jeong, S.; Hsu, Y.; Andrews, A. E.; Bianco, L.; Vaca, P.; Wilczak, J. M.; Fischer, M. L.

2012-12-01

64

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

E-print Network

1. INTRODUCTION The continuous growth of energy need together with the advantages brought a profoundly irregular primary source, the wind. The characteristics of the wind energy source are important in different aspects regarding wind energy exploitation. The energy available in the wind varies with the cube

Paris-Sud XI, Université de

65

Study on Soft-Sensing Model of Tower Crane Load Moment Based on Functional Link Neural Network  

Microsoft Academic Search

In soft-sensing of tower crane load moment, the nonlinear relation between the load moment and the horizontal displacement of moment limiter is indicated by analysis of working principle of elastic steel plate type load moment limiter. This paper proposes a soft-sensing model based on functional link neural network (FLNN) with the horizontal displacement of moment limiter as input and the

Quanmin Guo; Yongfeng Jia

2010-01-01

66

Dynamic modelling of a wind catcher\\/tower turret for natural ventilation  

Microsoft Academic Search

This paper discusses experimental and theoretical investigations and Computational Fluid Dynamics (CFD) modelling considerations to evaluate the performance of a square section wind catcher system connected to the top of a test room for the purpose of natural ventilation. The magnitude and distribution of pressure coefficients (Cp) around a wind catcher and the air flow into the test room were

Abbas Ali Elmualim

2006-01-01

67

Network Design and Implementation of the Emote Dynamic Monitoring System on Servicing Tower Cranes  

Microsoft Academic Search

On the analysis of safety management for the tower crane, hardware and software were designed regarding to the dynamic monitoring system, embedded system, data collection and storage. Web-based remote dynamic monitoring method was proposed for tower crane, the function of each part, the data transfer process and system characteristics were analyzed. A new remote dynamic monitoring topology system which can

Chongren Gao; Yufeng Yin; Yuxi Han; Guang Zeng

2010-01-01

68

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

69

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

70

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/

71

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

72

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

73

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

74

Impact of assimilating met-tower, turbine nacelle anemometer and other intensified wind farm observation systems on 0 - 12h wind energy prediction using the NCAR WRF-RTFDDA model  

NASA Astrophysics Data System (ADS)

In collaboration with Xcel Energy and Vasaila Inc., the National Center for Atmospheric Research (NCAR) conducts modeling study to evaluate the existing and the enhanced intensive observation systems for wind power nowcasting and short-range forecasting at a northern Colorado wind farm. The NCAR WRF (Weather Research and Forecasting model) based Real-Time Four-Dimensional Data Assimilation (RTFDDA) and forecasting system, which has been employed to support Xcel Energy operational wind forecast, was used in this study. The observational data include ten met-towers, a 915Hz wind profiler, a sodar and a Windcube Doppler lidar, besides the in-farm met-towers and wind speed and power reports from more than 300 of wind turbines. The WRF-RTFDDA 4-dimensioanl data assimilation algorithm allows to spread and propagate observation information in the WRF model space (x, y, z and time) with weighting functions built according to the observation location and time. The WRF-RTFDDA was set up to run with four nested domains with grid increments of 30, 10, 3.333 and 1.111km respectively. The standard and diverse non-conventional observations are assimilated on coarse grid domains along with the special wind farm observations. In this study, we investigate a) spread of surface observations in PBL according to PBL depth and regimes, b) optimization of horizontal influence radii and steep-terrain adjustment, and c) impact of different observation platforms and data types on 0 - 12 h wind prediction . It is found that PBL mixing and thermodynamic structures are greatly influenced by the PBL parameterization formulation. The range of the data assimilation effect on forecasts relies on weather and PBL regimes. In most cases, assimilation of in-farm and near-farm observations improves up to 12-hour wind power prediction and assimilation of in-farm data can significantly improves 0 - 6 hour forecasts.

Liu, Y.; Cheng, W.; Liu, Y. W.; Wiener, G.; Frehlich, R.; Mahoney, W.; Warner, T.; Himelic, J.; Parks, K.; Early, S.

2010-09-01

75

Balsa Towers  

NSDL National Science Digital Library

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

Techtronics Program

76

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

77

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

78

Wind farm modeling based on BP neural network  

Microsoft Academic Search

Wind farm modeling is an important research topic, but the traditional mechanism modeling method is difficult to get accurate models. However, performance of the neural network model is superior for identification and approximation of complex nonlinear systems. Especially, the BP network has been widely and successfully used in the engineering field. This paper gives a brief introduction to the BP

Youjie Ma; Yue Liu; Xuesong Zhou; Haishan Yang

2010-01-01

79

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

80

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

81

Global network of slow solar wind  

NASA Astrophysics Data System (ADS)

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.

2012-04-01

82

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  

NASA Astrophysics Data System (ADS)

This study presents observations of atmospheric boundary layer CO2mole fraction from a nine-tower regional network deployed during the North American Carbon Program's Mid-Continent Intensive (MCI) during 2007-2009. The MCI region is largely agricultural, with well-documented carbon exchange available via agricultural inventories. By combining vegetation maps and tower footprints, we show the fractional influence of corn, soy, grass, and forest biomes varies widely across the MCI. Differences in the magnitude of CO2 flux from each of these biomes lead to large spatial gradients in the monthly averaged CO2mole fraction observed in the MCI. In other words, the monthly averaged gradients are tied to regional patterns in net ecosystem exchange (NEE). The daily scale gradients are more weakly connected to regional NEE, instead being governed by local weather and large-scale weather patterns. With this network of tower-based mole fraction measurements, we detect climate-driven interannual changes in crop growth that are confirmed by satellite and inventory methods. These observations show that regional-scale CO2 mole fraction networks yield large, coherent signals governed largely by regional sources and sinks of CO2.

Miles, Natasha L.; Richardson, Scott J.; Davis, Kenneth J.; Lauvaux, Thomas; Andrews, Arlyn E.; West, Tristram O.; Bandaru, Varaprasad; Crosson, Eric R.

2012-03-01

83

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

84

Magnet Tower  

NSDL National Science Digital Library

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

Workshop, Mission S.

2013-01-01

85

Optimizing the Design of a Wind Farm Collection Network  

E-print Network

produced through eco-friendly means, such as wind turbines or solar panels. In this article we study-ground network, · above-ground transmission lines that usually follow existing roads and link two geographical points (i.e., road intersections), and · disconnects between the endpoints of UG cables and the above

Hertz, Alain

86

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

87

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

88

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

89

'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

90

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

E-print Network

2 33 3 3 1 1 1 1 1 1 2 2 Network of offshore wind farms connected by gas insulated transmission is a GIL? Why GIL? Acknowledgements Network of wind farms Comparison with other transmission systems AC wind farms in one line over the German island Norderney. 3 GIL is an AC transmission system for high

Heinemann, Detlev

91

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

92

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

93

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)

94

Ocean breeze monitoring network at the Oyster Creek Nuclear Plant  

SciTech Connect

The Oyster Creek Nuclear Generating Station (OCNGS) is located in New Jersey 10 km west of the Atlantic Ocean. Routine meteorological monitoring at the station has consisted of a single meteorological tower 120 m high and instrumented at the 10-m, 46-m, and 116-m levels. An analysis of 5 yr of data from this tower showed the OCNGS is affected by an ocean breeze approx. 1 day out of 4 during May through August. This suggested the need for meteorological monitoring in addition to the single met tower at OCNGS. As a result of the 1985 OCNGS meteorological monitoring study, GPU Nuclear established an ocean breeze monitoring network in the fall of 1986. It is a permanent part of OCNGS meteorological monitoring and consists of the same sites as used in the 1985 field study. Meteorological towers are located at the ocean site, the inland site, and at OCNGS. The ocean tower is 13 m (43 ft) high, the inland tower 10 m (33 ft), and the OCNGS tower 116 m (380 ft). Wind speed, wind direction, and temperature are measured on each tower; delta-temperature is also measured on the main tower. The instruments are calibrated in the spring, summer, and fall. The network is operated and maintained by GPU Nuclear Environmental Controls. The ocean breeze monitoring network and meteorological information system forms the basis for including the effects of the ocean breeze in OCNGS emergency off-site dose assessment.

Heck, W.

1987-01-01

95

Flux Sampling Errors for Aircraft and Towers  

NASA Technical Reports Server (NTRS)

Various errors and influences leading to differences between tower- and aircraft-measured fluxes are surveyed. This survey is motivated by reports in the literature that aircraft fluxes are sometimes smaller than tower-measured fluxes. Both tower and aircraft flux errors are larger with surface heterogeneity due to several independent effects. Surface heterogeneity may cause tower flux errors to increase with decreasing wind speed. Techniques to assess flux sampling error are reviewed. Such error estimates suffer various degrees of inapplicability in real geophysical time series due to nonstationarity of tower time series (or inhomogeneity of aircraft data). A new measure for nonstationarity is developed that eliminates assumptions on the form of the nonstationarity inherent in previous methods. When this nonstationarity measure becomes large, the surface energy imbalance increases sharply. Finally, strategies for obtaining adequate flux sampling using repeated aircraft passes and grid patterns are outlined.

Mahrt, Larry

1998-01-01

96

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

97

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

98

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

Federal Register 2010, 2011, 2012, 2013

...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

99

DFIG-based wind farm electromagnetic dynamic model and impact on protection relay of transmission network  

Microsoft Academic Search

A DFIG-based wind generator electromagnetic transient model is established on the RTDS platform in this paper. Stator flux oriented vector control scheme is adopted to achieve power decoupling control in the DFIG based wind model. In order to research the impact of the wind farm on the existing protection relay of the network, this paper establishes single machine electromagnetic dynamic

Guanghui Li; Baohui Zhang; Jin Wang; Zhiqian Bo; Tony Yip; David Writer; Yu-ming Lei

2011-01-01

100

Large scale offshore wind farms to be connected to the transmission network  

Microsoft Academic Search

The integration of wind energy is one of the major tasks for the transmission and distribution network. Large scale wind farms are often at remote places where the loads are low. Distributed smaller wind farms are spread over the area and insert their energy at the medium voltage level at 10 - 30 kV. In this paper the activities in

H. Koch

2009-01-01

101

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

102

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

103

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

104

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

105

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

106

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

107

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

E-print Network

­April, 3 rd 2008. Network of offshore wind farms connected by gas insulated transmission lines? Anja Summary The offshore wind power industry faces two major challenges: the connection of wind farms wind farms in one line. Its superior electric behavior makes it applicable for long distance

Heinemann, Detlev

108

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

109

Voltage Stability Analysis of Wind Farm Integration into Transmission Network  

Microsoft Academic Search

In some regional grids in China, wind power penetration will increase rapidly because of the abundant wind resources in those areas and the government policy impetus. However, the power system security and stability may be affected due to the higher wind power penetration. Because majority of the wind farms with higher installed capacity intends to be connected into the transmission

Yongning Chi; Yanhua Liu; Weisheng Wang; Huizhu Dai

2006-01-01

110

Optimal control of wind turbine using neural networks  

Microsoft Academic Search

Variable-speed, fixed-pitch wind turbines are required to optimize power output performance without the aerodynamic controls. In steady-state, a wind turbine generator system is operated such that the optimum points of wind rotor curve and electrical generator curve coincide. In order to obtain maximum power output of a wind turbine generator system, it is necessary to drive the wind turbine at

Mahinsasa Narayana; Ghanim Putrus

2010-01-01

111

A numerical study of interacting buoyant cooling-tower plumes  

Microsoft Academic Search

The compact design of mechanical cooling towers necessitates that the plumes are issued into the cross-wind in close proximity. An improved understanding of the interaction of adjacent plumes is therefore required for better design of such cooling towers, which may lead to a reduction in their environmental impact. This paper presents the results of a numerical investigation into the interaction

R. B. Bornoff; M. R. Mokhtarzadeh-Dehghan

2001-01-01

112

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

113

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

114

The application of the fuzzy neural network BP network based in the constant speed control of the new vertical wind turbine  

Microsoft Academic Search

This paper studied the method of the wind turbine's dynamic modeling creation based on the research of the relationship between the blade attack angle of the new vertical wind turbine and its efficiency, and also studied the fuzzy neural network algorithm based on BP network which was applied in the constant speed control of such a new vertical wind turbine.

Qian Zhang; Shuangling Wang; Huige Chen

2010-01-01

115

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

116

Predicting geomagnetic storms from solar-wind data using time-delay neural networks  

Microsoft Academic Search

We have used time-delay feed-forward neural networks to compute the geomagnetic-activity index Dst one hour ahead from a temporal sequence of solar-wind data. The input data include solar-wind density n, velocity V and the southward component Bz of the interplanetary magnetic field. Dst is not included in the input data. The networks implement an explicit functional relationship between the solar

H. Gleisner; H. Lundstedt; P. Wintoft

1996-01-01

117

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

118

A robust wind turbine control using a Neural Network based wind speed estimator  

Microsoft Academic Search

Modern wind turbines are capable to work in variable speed operations. These wind turbines are provided with adjustable speed generators, like the double feed induction generator. One of the main advantage of adjustable speed generators is that they improve the system efficiency compared to fixed speed generators because turbine speed is adjusted as a function of wind speed to maximize

Oscar Barambones

2010-01-01

119

Economic evaluation of the dual mode CAES solution for increased wind energy contribution in autonomous island networks  

Microsoft Academic Search

Wind parks operating in autonomous island grids, such as those encountered in the Aegean Archipelago, face considerable wind energy curtailments, owed to the inability of local electricity networks to absorb the entire wind energy production. On the other hand, plans promoting the natural gas-based electricity generation in big islands (such as Crete) question the future of wind energy. To recover

D. Zafirakis; J. K. Kaldellis

2009-01-01

120

A Neural Network Based Approach to Wind Energy Yield Forecasting  

Microsoft Academic Search

\\u000a It is commonly acknowledged that wind energy is the leading renewable energy generation method; currently producing a power\\u000a yield equivalent to 35 GW, with an estimated projection of 40-60 GW by 2012. In order to successfully integrate wind energy\\u000a with traditional generation supplies it is necessary to have the ability to accurately forecast the available yield of a wind\\u000a installation

Piers R. J. Campbell; Faheem Ahmed; Haydar Fathulla; Ahmad D. Jaffar

121

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

122

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

123

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

124

Air radiator cooling tower  

Microsoft Academic Search

The invention discloses an air radiator cooling tower comprising a piping system for the supply and removal of water circulating in cooled tubular elements joined into groups by means of tubular girders, an exhaust tower for the circulation of cooling air, and a device for the excitation of oscillations transmitted through direct contact over the surface of the tubular elements

B. B. Kazanovich; G. R. Santurian; P. A. Fischenko

1979-01-01

125

Structural Monitoring of Wind Turbines using Wireless Sensor Networks  

E-print Network

of alternative energy sources increasing, monitoring and economical design of alternative energy generators and carbon-neutral energy sources, wind energy is gaining popularity as perhaps the most technologically developed and practical alternative today. Recent studies put the annual wind energy generation capacity

Lynch, Jerome P.

126

Cooling tower waste reduction  

SciTech Connect

At Lawrence Livermore National Laboratory (LLNL), the two main cooling tower systems (central and northwest) were upgraded during the summer of 1997 to reduce the generation of hazardous waste. In 1996, these two tower systems generated approximately 135,400 lbs (61,400 kg) of hazardous sludge, which is more than 90 percent of the hazardous waste for the site annually. At both, wet decks (cascade reservoirs) were covered to block sunlight. Covering the cascade reservoirs reduced the amount of chemical conditioners (e.g. algaecide and biocide), required and in turn the amount of waste generated was reduced. Additionally, at the northwest cooling tower system, a sand filtration system was installed to allow cyclical filtering and backflushing, and new pumps, piping, and spray nozzles were installed to increase agitation. the appurtenance upgrade increased the efficiency of the cooling towers. The sand filtration system at the northwest cooling tower system enables operators to continuously maintain the cooling tower water quality without taking the towers out of service. Operational costs (including waste handling and disposal) and maintenance activities are compared for the cooling towers before and after upgrades. Additionally, the effectiveness of the sand filter system in conjunction with the wet deck covers (northwest cooling tower system), versus the cascade reservoir covers alone (south cooling tower south) is discussed. the overall expected return on investment is calculated to be in excess of 250 percent. this upgrade has been incorporated into the 1998 DOE complex-wide water conservation project being led by Sandia National Laboratory/Albuquerque.

Coleman, S.J.; Celeste, J.; Chine, R.; Scott, C.

1998-05-01

127

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

128

Neural network approximations for nonlinear interactions in wind wave spectra: direct mapping for wind seas in deep water  

NASA Astrophysics Data System (ADS)

The potential of Neural Networks (NN) to provide accurate estimates of nonlinear interactions for wind wave spectra by means of direct mapping is considered. Expanding on a previously reported feasibility study, an Empirical Orthogonal Functions (EOF) based NN for single peaked spectra is shown to be much more accurate than the well known Discrete Interaction Approximation (DIA), at the expense of a moderate increase of computational costs. This Neural Network Interaction Approximation (NNIA) gives reasonable results for modeled wave spectra, but is not yet capable of providing acceptable model integrations. Methods to expand the NNIA to be suitable for model integration are discussed.

Tolman, Hendrik L.; Krasnopolsky, Vladimir M.; Chalikov, Dmitry V.

129

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

130

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

131

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

132

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER SIX WITH TOWERS ...  

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

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER SIX WITH TOWERS SEVEN, EIGHT, NINE, TEN, AND BREAK OVER TOWER IN DISTANCE, LOOKING NORTH. TOWER SIX IS THE LAST BEFORE A DEEP CHASM, AS IS SEEN BY THE DISTANCE BETWEEN TOWERS SIX AND SEVEN. SEE CA-291-21 FOR IDENTICAL B&W NEGATIVE. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

133

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER SIX WITH TOWERS ...  

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

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER SIX WITH TOWERS SEVEN,EIGHT, NINE, TEN, AND BREAK OVER TOWER IN DISTANCE, LOOKING NORTH. TOWER SIX IS THE LAST BEFORE A DEEP CHASM, AS IS SEEN BY THE DISTANCE BETWEEN TOWERS SIX AND SEVEN. SEE CA-291-48 (CT) FOR IDENTICAL COLOR TRANSPARENCY. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

134

The Tower Challenge  

NSDL National Science Digital Library

This activity is an exciting and highly interactive opportunity for students to exercise their creativity and design skills. Working in cooperative groups, students are challenged to explore the geometry of tower design and construction, first by experime

Eichinger, John

2009-05-30

135

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

136

Cooling Towers Make Money  

E-print Network

COOLING TOWERS MAKE MONEY Robert Burger President ABSTRACT Question:-Why is the low bidder system a sacred cow? If contractors understand, by specifications, that the second low bidder will be awarded the contract all bidders will do... compliance and performanc are not safeguarded in the bid specification documents. With cooling towers, for instance, t e Wet Bulb Temperature criteria ofDesign is! extremely important. One or two degrees off can mean many dollars in costs...

Burger, R.

137

Hurricane Frances Rain Towers  

NSDL National Science Digital Library

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

Perkins, Lori; Halverson, Jeff

2005-04-11

138

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 ...

139

Contemporary Mathematics WINDING NUMBERS FOR NETWORKS WITH WEAK  

E-print Network

concrete example would be a networked collection of accelerometers or acoustic sensors distributed be computed in a number of ways, including: (1) analytically: via integrating the tangent vector to L about L, sensor network, degree, unit disk graph. c 0000 (copyright holder) 1 #12;2 ROBERT GHRIST which x0

Ghrist, Robert W.

140

Preliminary comparison of data from the Säntis Tower and the EUCLID lightning location system  

Microsoft Academic Search

In this paper, direct lightning current measurements obtained on the Säntis Tower from June 1st, 2010 to May 31st, 2011 are used to evaluate the ability of the EUCLID lightning detection network to detect this type of lightning triggered by a tall tower in terms of detection efficiency, location accuracy and peak current estimates. The Säntis Tower is a 124-meter

Carlos Romero; Mario Paolone; Farhad Rachidi; Marcos Rubinstein; Abraham Rubinstein; Gerhard Diendorfer; Wolfgang Schulz; Marina Bernardi; Carlo Alberto Nucci

2011-01-01

141

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

NASA Astrophysics Data System (ADS)

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

Marcillo, O. E.; Arrowsmith, S.

2013-12-01

142

Detail of wire ground screen in relation to towers, looking ...  

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

Detail of wire ground screen in relation to towers, looking southeast - 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

143

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

Microsoft Academic Search

This dissertation investigates the application of neural network theory to the analysis of a 4-kW Utility-interactive Wind-Photovoltaic System (WPS) with battery storage. The hybrid system comprises a 2.5-kW photovoltaic generator and a 1.5-kW wind turbine. The wind power generator produces power at variable speed and variable frequency (VSVF). The wind energy is converted into dc power by a controlled, tree-phase,

Francois Giraud

1999-01-01

144

Research on rotor excitation neural network PID control of variable speed constant frequency wind turbine  

Microsoft Academic Search

The key of variable speed constant frequency wind turbine operating control is the rotor excitation control, This article state the double-fed generator stator magnetic field direction detection control principle, discussed the stator magnetic field localization and the rotor position definite method, The rotor excitation uses neural network PID control which realizes easily in DSP, and has developed the DSP rotor

Xingjia Yao; Hexu Wen; Ying Deng; Zhongcong Zhang

2007-01-01

145

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

Microsoft Academic Search

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.

L. J. Gilbert

1977-01-01

146

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

147

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

148

Local–global analysis of cooling tower with cutouts  

Microsoft Academic Search

The local–global strategy is extended to column-supported reinforced concrete shell structures and applied to the nonlinear structural analysis of a column-supported reinforced concrete cooling tower shell with imperfections. In the numerical examples a column-supported R\\/C cooling tower with openings is considered and the nonlinear behavior is computed under a combination of dead load g and static wind pressure w. Especially,

Takashi Hara; Phillip L. Gould

2002-01-01

149

Flexible dynamics of floating wind turbines  

E-print Network

This work presents Tower Flex, a structural dynamics model for a coupled analysis of offshore floating wind turbines consisting of a tower, a floating platform and a mooring system. In this multi-body, linear frequency-domain ...

Luypaert, Thomas (Thomas J.)

2012-01-01

150

Cooling Towers- Energy Conservation Strategies Understanding Cooling Towers  

E-print Network

Cooling towers are energy conservation devices that Management, more often than not, historically overlooks in the survey of strategies for plant operating efficiencies. The utilization of the colder water off the cooling tower is the money maker!...

Smith, M.

151

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

152

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

153

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER TWO, WITH TOWERS ...  

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

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER TWO, WITH TOWERS THREE,FOUR, FIVE AND SIX IN DISTANCE, LOOKING NORTHEAST. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

154

Meteorological Monitoring And Warning Computer Network  

NASA Technical Reports Server (NTRS)

Meteorological monitoring system (MMS) computer network tracks weather conditions and issues warnings when weather hazards are about to occur. Receives data from such meteorological instruments as wind sensors on towers and lightning detectors, and compares data with weather restrictions specified for outdoor activities. If weather violates restriction, network generates audible and visible alarms to alert people involved in activity. Also displays weather and toxic diffusion data and disseminates weather forecasts, advisories, and warnings to workstations.

Evans, Randolph J.; Dianic, Allan V.; Moore, Lien N.

1996-01-01

155

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

156

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.

Indianapolis, The C.

2006-01-01

157

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

158

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

159

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

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

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

160

Pays-Bas (2008)" Assessing Available Transfer Capacity on a Realistic European Network: Impact of Assumptions on Wind Power Generation  

E-print Network

Abstract—This paper aims at assessing the impact of massive wind power penetration on the calculation of Available Transfer Capacity (ATC) for the interconnections between European countries. Calculations are made for the ATC between France and Belgium and are realized on a realistic European Electricity Network. We find that the German wind power production make this ATC vary depending on the total wind power production and its geographical distribution in Germany. Wind power production and the nodes involved in cross-border exchange must then be forecast precisely so that the cross-border exchange can be maximal without breaching network security. L I.

Vincent Rious; Julio Usaola; Marcelo Saguan; Jean-michel Glachant

2008-01-01

161

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

162

Vice President CEO, Tower Foundation  

E-print Network

Business Director of Development Education Director of Development Science Director of Development Social Administrative Assistant Tower Foundation HR Director Tower Foundation Accounts Payable Technician Director Media and Budgets Associate Vice President Marketing and Communications Director of Development Athletics Managing

Su, Xiao

163

OCCUPATIONAL COOLING TOWERS  

E-print Network

BLOOD COLLECTION LAB PLATELET DONATION GRADUATE EDUCATION ID CLINIC THE CAFE MAIL ROOM A B C MACNIDER HEALTH SCIENCES LIBRARY COOLING TOWERS EMPLOYEE HEALTH B C D F E CHILDREN'S ELEVATORS MEDICAL SCHOOL) MEDICALDR. WOMEN'S SERVICES BLOOD BANK FIRST FLOOR OF UNC HOSPITALS BERRYHILL OIS DIGITAL MEDIA SERVICES

Crews, Stephen

164

Cooling Towers, The Debottleneckers  

E-print Network

Power generating plants and petro-chemical works are always expanding. An on-going problem is to identify and de-bottle neck restricting conditions of growth. The cooling tower is a highly visible piece of equipment. Most industrial crossflow units...

Burger, R.

165

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

166

Cell Towers and Songbirds  

ERIC Educational Resources Information Center

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

Klosterman, Michelle; Mesa, Jennifer; Milton, Katie

2009-01-01

167

Research on intelligent monitoring and protection system of distributive multi-tower cranes  

Microsoft Academic Search

During construction phase of large buildings, it is of great significance to maintain safety protection on multi-tower cranes operating. Based on distributive and multi-intelligent agents design concept, and adopting ARM embedded technology, wireless network transmission, an intelligent monitor and protection system for the multi-tower cranes has been established. A multi-tower crane communication network has been set up to realize status

Gu Liang-yao; Yang yue; Chen Feng

2010-01-01

168

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

169

PERFORMANCE ANALYSIS OF MECHANICAL DRAFT COOLING TOWER  

SciTech Connect

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

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

2009-02-10

170

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

171

MPPT control strategy for wind energy conversion system based on RBF network  

Microsoft Academic Search

This paper presents maximum-power-point-tracking (MPPT) based control algorithms for optimal wind energy capture using radial basis function network (RBFN) and a proposed torque observer MPPT algorithm. The design of a high-performance on-line training RBFN using back-propagation learning algorithm regulating controller for the sensorless control of a permanent magnet synchronous generator (PMSG). The PMSG is controlled by the loss-minimization control with

Whei-Min Lin; Chih-Ming Hong; Fu-Sheng Cheng; Kai Hung Lu

2011-01-01

172

Initial Operation Results and Performance Evaluation of WINDS (Wideband Inter-Networking engineering test and Demonstration Satellite)  

NASA Astrophysics Data System (ADS)

WINDS was launched in late February 2008 to demonstrate technologies enabling an ultra-high data rate communication network. WINDS is performing initial functional verifications of onboard components and systems. This paper describes the initial operation results on orbit and evaluates the performance based on the design and simulation data.

Arikawa, Yoshihisa; Nakamura, Yasuo; Araki, Tsunehiko; Fujiwara, Yuuichi; Baba, Isao; Baba, Kenichi

173

STATISTICAL CORRELATIONS OF SURFACE WIND DATA: A COMPARISON BETWEEN A NATIONAL WEATHER SERVICE STATION AND A NEARBY AEROMETRIC MONITORING NETWORK  

EPA Science Inventory

This report presents a statistical analysis of wind data collected at a network of stations in the Southeast Ohio River Valley. The purpose of this study is to determine the extent to which wind measurements made by the National Weather Service (NWS) station at the Tri-State Airp...

174

The study on tower crane foundation slope model based on inclination feature  

Microsoft Academic Search

It is a major hidden danger of accidents in work when tower crane foundation is sinking and slope, it has been one of the difficulties in the field of tower crane's design and research that how to detect the feature of sinking and slope automatically and distinguish this feature from other hidden danger characteristics. In this paper, wind and inertia

Song Shi-jun; Qiao Cai-feng; Wang Ji-yong

2011-01-01

175

Zinc and cadmium in soils and plants near electrical transmission (hydro) towers  

Microsoft Academic Search

Concentrations of Zn and Cd were determined in plants and soils around and beneath corroding galvanized electrical transmission (hydro) towers located in different habitats near Peterborough, Ontario. High concentrations of Zn occurred in a well-drained, uncultivated drumlin soil around and beneath a tower. The pattern of contamination indicated spread of Zn by runoff and by wind-driven spray and water droplets

Roger Jones; Magdalena S. E. Burgess

1984-01-01

176

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

177

Periodic pulsations from a three-bladed wind turbine  

Microsoft Academic Search

In this paper, periodic power pulsations from a three-bladed wind turbine are analyzed. The influence of wind shear, wind speed, turbulence intensity, rotor position and tower oscillation is investigated. No clear dependence between the periodic power components and the wind shear or turbulence intensity has been verified. The investigated turbine sometimes produces large power pulsations at the tower resonance frequency.

Torbjörn Thiringer; Jan-Åke Dahlberg

2001-01-01

178

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

179

Multi-tower solar array  

Microsoft Academic Search

The multi-tower solar array (MTSA) is a new concept of a point focussing two-axis tracking concentrating solar power plant. The MTSA consists of several tower-mounted receivers which stand so close to each other that the heliostat fields of the towers partly overlap. Therefore, in some sectors of the heliostat field neighbouring heliostats are alternately directed to the receivers on different

Philipp Schramek; David R. Mills

2003-01-01

180

Improving Process Cooling Tower Eddiciency  

E-print Network

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

Turpish, W.

2013-01-01

181

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

182

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

183

Weird Geology: The Devil's Tower  

NSDL National Science Digital Library

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

Krystek, Lee; Mystery, The M.

184

Hybrid Evaporative - Condenser Cooling Tower  

Microsoft Academic Search

The need to save energy in power producing and power consuming systems and the fact that evaporative cooling is the most efficient method for heat rejection led to the design and testing of a model of a special cooling tower, fn this hybrid system an evaporative condenser is being built into the cooling tower and the advantages of evaporative cooling

Uriyel Fisher; Wolfgang Leidenfrost; Jiashang Li

1981-01-01

185

29 CFR 1926.1435 - Tower cranes.  

...2014-07-01 2014-07-01 false Tower cranes. 1926.1435 Section 1926...Construction § 1926.1435 Tower cranes. (a) This section contains supplemental requirements for tower cranes; all sections of this...

2014-07-01

186

29 CFR 1926.1435 - Tower cranes.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Tower cranes. 1926.1435 Section 1926...Construction § 1926.1435 Tower cranes. (a) This section contains supplemental requirements for tower cranes; all sections of this...

2013-07-01

187

29 CFR 1926.1435 - Tower cranes.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Tower cranes. 1926.1435 Section 1926...Construction § 1926.1435 Tower cranes. (a) This section contains supplemental requirements for tower cranes; all sections of this...

2011-07-01

188

29 CFR 1926.1435 - Tower cranes.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Tower cranes. 1926.1435 Section 1926...Construction § 1926.1435 Tower cranes. (a) This section contains supplemental requirements for tower cranes; all sections of this...

2012-07-01

189

Installation and initial operation of a 4100 watt wind turbine  

NASA Technical Reports Server (NTRS)

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

Tryon, H. B.; Richards, T.

1975-01-01

190

Scanning Doppler Lidar Measurements for Wind Energy Applications  

Microsoft Academic Search

The development of wind energy has increased rapidly along with the size and capacity of wind turbines. These larger machines require detailed wind resource measurements at higher and higher altitudes. Accurate wind speed, wind direction, and turbulence statistics are required for wind resource assessment and efficient wind farm operation. Tower measurements are limited in coverage and do not provide the

R. Frehlich; N. Kelley

2008-01-01

191

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

192

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

Microsoft Academic Search

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

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

2010-01-01

193

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

194

Cooling towers, the neglected orphan  

SciTech Connect

What is the relationship between generating electricity and generating colder water? Knowledgeable engineers pay close attention to their sophisticated electric generating equipment but many ignore and take the seemingly simple cooling tower in the back yard for granted. When high head pressures occur in compressors and poor vacuums are evident in condensers, especially at peak demand, the cooling tower usually is the culprit and the limiting factor of production. As turbine back pressures increase, a plant experiences decreased cycle efficiency. This back pressure, in part, is due to insufficient cold cooling water discharging off the cooling tower. A recent joint survey by the Tennessee Valley Administration (TVA) and the Electric Power Research Institute (EPRI) which appeared in the August 1988 issue of Power Engineering Magazine indicated that 6% of the generating plants they examined with wet cooling towers, were operating at 80% of design purchased capacity. In other words, they were 20% short of being able to produce design kW output during peak demand and were costing industry over $250,000,000 per year in added fuel costs or lost retail sales, as reported in the article. This presentation will explain how that situation came about and delineates state-of-the-art retrofit technique to optimize the cooling tower`s cold water output to remedy the situation. Actual field retrofit conditions will illustrate how existing configurations of cooling towers can be upgraded with minimum structural and mechanical equipment change.

Burger, R.

1996-12-31

195

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

196

The effect of a tall tower on flow and dispersion through a model urban neighborhood: part 2. Pollutant dispersion.  

PubMed

This article is the second in a two-paper series presenting results from wind tunnel and computational fluid dynamics (CFD) simulations of flow and dispersion in an idealized model urban neighborhood. Pollutant dispersion results are presented and discussed for a model neighborhood that was characterized by regular city blocks of three-story row houses with a single 12-story tower located at the downwind edge of one of these blocks. The tower had three significant effects on pollutant dispersion in the surrounding street canyons: drawing the plume laterally towards the tower, greatly enhancing the vertical dispersion of the plume in the wake of the tower, and significantly decreasing the residence time of pollutants in the wake of the tower. In the wind tunnel, tracer gas released in the avenue lee of the tower, but several blocks away laterally, was pulled towards the tower and lifted in the wake of the tower. The same lateral movement of the pollutant was seen in the next avenue, which was approximately 2.5 tower heights downwind of the tower. The tower also served to ventilate the street canyon directly in its wake more rapidly than the surrounding areas. This was evidenced by CFD simulations of concentration decay where the residence time of pollutants lee of the 12-story tower was found to be less than half the residence time behind a neighboring three-story building. This same phenomenon of rapid vertical dispersion lee of a tower among an array of smaller buildings was also demonstrated in a separate set of wind tunnel experiments using an array of cubical blocks. A similar decrease in the residence time was observed when the height of one block was increased. PMID:20024014

Brixey, Laurie A; Heist, David K; Richmond-Bryant, Jennifer; Bowker, George E; Perry, Steven G; Wiener, Russell W

2009-12-01

197

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

198

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

199

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.

200

Wind Farm Feasibility Study  

Microsoft Academic Search

Saint Francis University has assessed the Swallow Farm property located in Shade Township, Somerset County, Pennsylvania as a potential wind power development site. Saint Francis worked with McLean Energy Partners to have a 50-meter meteorological tower installed on the property in April 2004 and continues to conduct a meteorological assessment of the site. Results suggest a mean average wind speed

Richard Curry; Erik Foley; DOE Project Officer

2007-01-01

201

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

202

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

203

Beware of nominal cooling towers  

SciTech Connect

This article describes how taking into account WBT tower performance can save millions in revenue and fuel costs. A 3 F temperature increase caused by an inefficient or poorly functioning cooling tower could cost a 300-kW power plant as much as $300,000 annually in lost sales. The revenue lost from operating a generating plant with circulating water temperatures hotter than those designed for the plant is illustrated. Colder water from cooling towers is responsible for producing better vacuums, relieving back pressure on turbines and lowering heat temperatures and pressures. As a result of cooling tower inefficiencies and the resulting higher temperature, the plant must burn additional fuel to overcome operation at lower efficiency levels and vacuums. The alternative is lower electricity generation and loss of sales. The added fuel costs caused by higher circulating water temperatures are illustrated.

Burger, R.

1996-06-01

204

World Federation of Great Towers  

NSDL National Science Digital Library

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

205

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

206

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

207

Carillon Studio Recital Century Tower  

E-print Network

music immediately before and after the annual "Sounds of the Seasons" presented by the School of Music on the afternoon of Sunday, December 3. About the Carillon Century Tower, a monument constructed in 1953 in memory

Guo, Jing

208

Modeling and control of scaled a tower crane system  

Microsoft Academic Search

In this paper, we proposed a hierarchical artificial neural network based adaptive fuzzy logic (HANNFL) control of flexible link carrying pendulum system which was assumed as scaled a tower crane system and capable to move in the horizontal plane. Simulation and experimental studies were realized to control position and tip displacement of the flexible link and swing angles of pendulum.

Mustafa Tinkir; Umit Onen; Mete Kalyoncu; Yusuf Sahin

2011-01-01

209

Runway Transgressions at Non-Towered and  

E-print Network

Runway Transgressions at Non-Towered and Tower-Closed Airports Runway Transgressions at Non View California 94043 NASA ASRS (Pub. 61) #12;ASRS Non-Towered Airports Runway Transgressions Study............................................................................ B-1 ­ 5 Appendix C -- ASRS Database Non-Towered Airport Runway Transgressions, 1997-2000...... C-1

210

Model validation: Cooling-tower performance  

Microsoft Academic Search

The purpose of the fill performance validation project is to examine the accuracy of the cooling tower computer models and fill performance data that have recently been made available through EPRI. This project compares actual full scale tower performance test results to those predicted by the tower models. The cooling tower models used in this project include: FACTS\\/FACTR, developed by

P. B. Miller; G. L. Starnes

1989-01-01

211

Dynamic response of guyed towers  

E-print Network

structures and the topic of guyed towers. Mark C. Gillcrist Spring, 1984 TABLE OF CONTENTS CHAPTER Page I INTRODUCTION Description of Guyed Tower Description of Prototype 1 3 II LITERATURE REVIEW III FINITE ELEMENT MODEL Structural Model... 50 years, oil production has gradually moved from the bayous and into the open ocean. In recent years this move toward deeper water has produced mammoth steel jacket structures such as Shell Oil's Cognac platform set in more than 1000-ft of water...

Gillcrist, Mark Christopher

2012-06-07

212

The Physics of Shot Towers  

ERIC Educational Resources Information Center

In the late 18th and throughout the 19th century, lead shot for muskets was prepared by use of a shot tower. Molten lead was poured from the top of a tower and, during its fall, the drops became spherical under the action of surface tension. In this article, we ask and answer the question: "How does the size of the lead shot depend on the height…

Lipscombe, Trevor C.; Mungan, Carl E.

2012-01-01

213

Physics in the Toy Room: Toppling Towers  

NSDL National Science Digital Library

In this physics activity, learners use square blocks to explore how towers fall. Learners attach a piece of string to the side of a block and then construct a tall tower on top of this base block. They observe what happens when they topple the tower by pulling the string. This activity guide explains why the tower bends and breaks and the role of acceleration and gravity in bringing the tower down.

Society, American P.

2011-01-01

214

Vibration Control of Bridge Tower Under Construction Using Active Mass Damper  

NASA Astrophysics Data System (ADS)

For large structures such as towers of suspension bridges or cable-stayed bridges, we often need to suppress wind-induced vibration for safety. Especially in the construction stage, the structures have a low tolerance than completed ones. This paper discusses the active vibration dampers used to suppress wind-induced vibration of a tower of a suspension bridge during a construction. The active damper was used to suppress wind-induced vibration in multiple modes predicted by wind-tunnel test. The controller design of the dampers is based on H? robust control theory. At each erection step, we measured dynamic properties of towers to adjust parameters of the controller using active vibration exciters. The measured dynamic properties of active controlled structures are compared with those of non-controlled structures. The analysis of free vibration shows the suppression performance of active damper as expected in the controller design.

Kagaya, Hiroaki; Tamaki, Toshihiro; Nishi, Yoshikazu; Nagao, Yoichi; Yamaguchi, Kazunori

215

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

216

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

217

Development of solar tower observatories  

NASA Astrophysics Data System (ADS)

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

Wolfschmidt, Gudrun

218

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

219

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

220

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

221

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.

222

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

223

Common misconceptions about cooling towers  

SciTech Connect

This article discusses the design and performance of the water cooling tower. In many cases the numbers presented in a cooling tower inquiry for thermal performance design represent a more stringent condition than that found in the operation of the unit. A common misconception is to take the service factor or safety factor in the cold water temperature or the wet bulb temperature. Service factors are used in the preparation of specifications for most industrial equipment. Standards specify a minimum service factor of 2.0 for cooling tower right angle spiral bevel gears. Closing the approach (cold water temperature minus wet bulb temperature) does not vary linearly with increasing difficulty of duty for the cooling tower, and consequently does not represent a straight-line increase in size or cost. A decrease in the specified approach is equivalent to a decrease in the driving force available for the transfer of mass and heat from the water to the air stream. A decrease in approach from 20 to 19/sup 0/F would result in an increase in cost of about 5%, while a decrease from 5 to 4/sup 0/F would require about 20% more cooling tower.

Willa, J.L.; Campbell, J.C.

1983-12-01

224

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

225

Survey of power tower technology  

NASA Astrophysics Data System (ADS)

The history of the power tower programs is reviewed, and attention is given to the current state of heliostat, receiver, and storage design. Economic considerations are discussed, as are simulation studies and implications. Also dealt with are alternate applications for the power tower and some financing and energy aspects of solar electric conversion. It is noted that with a national commitment to solar energy, the power tower concept could generate 40 GW of electricity and double this amount in process heat by the year 2000. Calculations show an energy amplification factor of 20 for solar energy plants; that is, the ratio of the electric energy produced over the lifetime of a power plant to the thermal energy required to produce the plant.

Hildebrandt, A. F.; Dasgupta, S.

1980-05-01

226

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

227

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

228

Twin tower gas fractionation apparatus  

Microsoft Academic Search

An apparatus for adsorptive fractionation of a gaseous mixture. The apparatus is a twin tower fractionator or dryer including a pair of sorbent beds. A filter and valve assembly directs a flow of the gaseous mixture from a source thereof to one of the beds for removing a gaseous component of said mixture while simultaneously directing a flow of purge

R. A. Null; L. C. laughlin; M. L. Goldberg

1985-01-01

229

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

230

The study of tower-inclination feature model under the normal state of tower crane  

Microsoft Academic Search

The tower crane fault status diagnosis has been one of difficult problems in the field of hoisting and transport. How to determine whether the tower crane steel structure meet the design requirements, and whether tower crane work normally and so on have been the trouble for all tower crane owners and managers. In this paper we studied the mechanical model

Song Shijun; Qiao Caifeng; Wang Jiyong; Song Lianyu

2010-01-01

231

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...

232

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

233

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

234

A numerical study of interacting buoyant cooling-tower plumes  

NASA Astrophysics Data System (ADS)

The compact design of mechanical cooling towers necessitates that the plumes are issued into the cross-wind in close proximity. An improved understanding of the interaction of adjacent plumes is therefore required for better design of such cooling towers, which may lead to a reduction in their environmental impact. This paper presents the results of a numerical investigation into the interaction of two adjacent plumes in a cross-flow. The numerical model simulates small-scale wind tunnel experiments of a cooling tower arrangement. The computations are performed for three-dimensional, turbulent, buoyant and interacting plumes, and for a single plume for comparison. Two double-source arrangements, namely, tandem and side-by-side, with respect to the oncoming atmospheric boundary layer are considered. A low Reynolds number k- ? turbulence model is used with two discretisation schemes, hybrid and QUICK, and the results are compared. Comparisons are also made with the experimental results. The results show that the interaction of side-by-side plumes is dominated by the interaction of the rotating vortex pairs within the plumes. A tandem source arrangement leads to early merging and efficient rise enhancement. Comparisons of the predicted results with experimental data show good agreement for the plume rise.

Bornoff, R. B.; Mokhtarzadeh-Dehghan, M. R.

235

Automated wind load characterization of wind turbine structures by embedded model updating  

NASA Astrophysics Data System (ADS)

The continued development of renewable energy resources is for the nation to limit its carbon footprint and to enjoy independence in energy production. Key to that effort are reliable generators of renewable energy sources that are economically competitive with legacy sources. In the area of wind energy, a major contributor to the cost of implementation is large uncertainty regarding the condition of wind turbines in the field due to lack of information about loading, dynamic response, and fatigue life of the structure expended. Under favorable circumstances, this uncertainty leads to overly conservative designs and maintenance schedules. Under unfavorable circumstances, it leads to inadequate maintenance schedules, damage to electrical systems, or even structural failure. Low-cost wireless sensors can provide more certainty for stakeholders by measuring the dynamic response of the structure to loading, estimating the fatigue state of the structure, and extracting loading information from the structural response without the need of an upwind instrumentation tower. This study presents a method for using wireless sensor networks to estimate the spectral properties of a wind turbine tower loading based on its measured response and some rudimentary knowledge of its structure. Structural parameters are estimated via model-updating in the frequency domain to produce an identification of the system. The updated structural model and the measured output spectra are then used to estimate the input spectra. Laboratory results are presented indicating accurate load characterization.

Swartz, R. Andrew; Zimmerman, Andrew T.; Lynch, Jerome P.

2010-04-01

236

Towards a Wind Energy Climatology at Advanced Turbine Hub-Heights: Preprint  

SciTech Connect

Measurements of wind characteristics over a wide range of heights up to and above 100 m are useful to: (1) characterize the local and regional wind climate; (2) validate wind resource estimates derived from numerical models; and (3) evaluate changes in wind characteristics and wind shear over the area swept by the blades. Developing wind climatology at advanced turbine hub heights for the United States benefits wind energy development. Tall tower data from Kansas, Indiana, and Minnesota (which have the greatest number of tall towers with measurement data) will be the focus of this paper. Analyses of data from the tall towers will start the process of developing a comprehensive climatology.

Schwartz, M.; Elliott, D.

2005-05-01

237

A Vortical Hot Tower Route to Tropical Cyclogenesis.  

NASA Astrophysics Data System (ADS)

A nonhydrostatic cloud model is used to examine the thermomechanics of tropical cyclogenesis under realistic meteorological conditions. Observations motivate the focus on the problem of how a midtropospheric cyclonic vortex, a frequent by-product of mesoscale convective systems during summertime conditions over tropical oceans, may be transformed into a surface-concentrated (warm core) tropical depression. As a first step, the vortex transformation is studied in the absence of vertical wind shear or zonal flow.Within the cyclonic vorticity-rich environment of the mesoscale convective vortex (MCV) embryo, the simulations demonstrate that small-scale cumulonimbus towers possessing intense cyclonic vorticity in their cores [vortical hot towers (VHTs)] emerge as the preferred coherent structures. The VHTs acquire their vertical vorticity through a combination of tilting of MCV horizontal vorticity and stretching of MCV and VHT-generated vertical vorticity. Horizontally localized and exhibiting convective lifetimes on the order of 1 h, VHTs overcome the generally adverse effects of downdrafts by consuming convective available potential energy in their local environment, humidifying the middle and upper troposphere, and undergoing diabatic vortex merger with neighboring towers.During metamorphosis, the VHTs vortically prime the mesoscale environment and collectively mimic a quasi-steady diabatic heating rate within the MCV embryo. A quasi-balanced toroidal (transverse) circulation develops on the system scale that converges cyclonic vorticity of the initial MCV and small-scale vorticity anomalies generated by subsequent tower activity. The VHTs are found to accelerate the spinup of near-surface mean tangential winds relative to an approximate axisymmetric model that excises the VHTs. This upscale growth mechanism appears capable of generating a tropical depression vortex on time scales on the order of 1 2 days, for reasonable parameter choices.Further tests of the VHT paradigm are advocated through diagnoses of operational weather prediction models, higher resolution simulations of the current configuration, examination of disruption scenarios for incipient vortices, and a meteorological field experiment.

Montgomery, M. T.; Nicholls, M. E.; Cram, T. A.; Saunders, A. B.

2006-01-01

238

Research and Design of Tower Crane Condition Monitoring and Fault Diagnosis System  

Microsoft Academic Search

Tower cranes are playing an important role in hoisting apparatus, while reducing tower crane accident and improving crane safety performance are always urgent. C8051F020 SCM is selected as the core of this system, and many advanced technology such as multisensor data acquisition, expert system and neural network are to be used. The system has self-contained condition monitor in and fault

Yang Yu; Zhenlian Zhao; Liang Chen

2010-01-01

239

The effect of a tall tower on flow and dispersion through a model urban neighborhood : Part 1. Flow characteristics  

Microsoft Academic Search

Wind tunnel and computational fluid dynamics (CFD) studies were performed to examine the effect of a tall tower on the flow around an otherwise uniform array of buildings. The model used in both the wind tunnel and CFD studies was designed to simulate an area of Brooklyn, NY, where blocks of residential row houses form a neighborhood bordering a major

David K. Heist; Laurie A. Brixey; Jennifer Richmond-Bryant; George E. Bowker; Steven G. Perry; Russell W. Wiener

2009-01-01

240

Fault Tolerance of DFIG Wind Turbine with a Series Grid Side Passive Impedance Network  

Microsoft Academic Search

Due to the increase of the number of wind turbines connected directly to the electric utility grid, new regulator codes have been issued that require low voltage ride-through capability for wind turbines so that they can remain online and support the electric grid during voltage sags. Conventional ride-through techniques for the doubly fed induction generator (DFIG) architecture result in compromised

Xiangwu Yan; Giri Venkataramanan; P. S. Flannery; Yang Wang

2009-01-01

241

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

242

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

243

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

SciTech Connect

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

Janet.twomey@wichita.edu

2010-04-30

244

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...

245

Detection of centripetal heat-island circulations from tower data in St. Louis  

Microsoft Academic Search

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-1, two data classes of several hundred hours each are formed. One class is associated with weak heat islands,

Jack H. Shreffler

1978-01-01

246

New Traffic Control Tower-South Pole  

NSF Publications Database

The proposed activity would replace an AN/TSQ-60 Portable Air Traffic Control (ATC) Unit now existing at the South Pole Station with a newer LNS TT-070 Portable (ATC) Tower and shelter. The following ATC tower and facility alternatives were considered and investigated: ? the "no-action" alternative; ? LNS TT-070 Portable ATC Tower (the preferred alternative); ? TSQ-120; ? TSQ-97; ? Barton Fixed; ? Barton Portable; ? Barton Mobile; ? LNS CTC-250 Fixed; and ? LNS ANT-57.

247

Auburn Tower ozone study 1993  

SciTech Connect

The Raleigh-Durham area has been designated as a moderate non-attainment area for ozone because of measured excessive ozone concentrations. Redesignation proceedings are in progress for this area. The Auburn Tower, a 2,000 foot broadcasting tower located about 10 miles southeast of Raleigh, provided the opportunity to perform multiple elevation atmospheric sampling. A study was designed to measure the ozone concentrations and organic compounds at three elevations. Three ozone monitors, hydrocarbon samplers and carbonyl samplers began sampling on July 23, 1993. Organic compounds were collected by contract laboratories who changed canisters and DNPH reagent cartridges and analyzed the samples. The organic sampling results are discussed in other related papers. Sampling continued until September 3, 1993 when all ozone equipment was audited and disconnected. Ozone was monitored continuously, 23 hours a day with one hour set aside for nightly automatic zero/span checks. Long sampling lines and probes were attached to the tower from each elevation down to the air conditioned room used for the ozone monitoring equipment. Heated lines and water traps were used inside this air conditioned room. The ozone concentrations measured are presented graphically. The normal diurnal pattern seen at ground level monitoring was not seen at 820 foot and 1,420 foot elevation. Daily averages and maximums were larger at elevated levels. The average ozone concentration at ground level for August was .034 ppm and at 1,420 foot level the average was .061 ppm. The maximums at ground level for August was .094 ppm versus the maximums for August at 1,420 foot level was .105 ppm. The study will continue in 1994.

Murray, G.C. Jr.; Manuszak, T.L.; Graves, R.S.; Gobel, M.J. [North Carolina Dept. of Environment, Health and Natural Resources, Raleigh, NC (United States)

1994-12-31

248

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

249

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

250

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

251

DIRECTIONS TO GREY TOWERS NATIONAL HISTORIC SITE 151 Grey Towers Dr.  

E-print Network

, and travel behind Apple Valley #12;Shops complex. The entrance to Grey Towers is up the road on your left, and travel behind Apple Valley Shops complex. The entrance to Grey Towers is up the road on your left complex. The entrance drive to Grey Towers is up the road on your left. Driving time is 1 hour. From

252

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

253

Cascading Kalman Observers of Structural Flexible and Wind States for Wind Turbine Control  

Microsoft Academic Search

We formulate novel observers of the structural flexible states of a wind turbine, as well as of the wind incident on its rotor. Stochastic filtering processes reconstruct on-line optimal estimates of the tower and blade states, by using readings from accelerometers and strain gages placed along the structural members. From these re- constructed states, another filtering process estimates the wind

C. L. Bottasso; A. Croce

254

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

255

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

256

IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 21, NO. 3, SEPTEMBER 2006 717 Simulation Model of Wind Turbine 3p Torque  

E-print Network

Turbine 3p Torque Oscillations due to Wind Shear and Tower Shadow Dale S. L. Dolan, Student Member, IEEE quality issues, the dynamic torque generated by the blades of a wind turbine must be represented turbine including the effects of wind shear and tower shadow. The comprehensive model includes turbine

Lehn, Peter W.

257

Design and Construction of a Scaled Whirl Tower Facility  

NASA Astrophysics Data System (ADS)

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

Pickard, John Alexander

258

COKE QUENCH TOWER EMISSION TESTING PROGRAM  

EPA Science Inventory

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

259

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

260

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

261

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

262

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

spacecraft will build on these successes, with the Japan-UK Solar-B and NASA Solar Dynamics Observatory (SDO-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

263

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

Microsoft Academic Search

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

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

2010-01-01

264

The Birl: An Electronic Wind Instrument Based on an Artificial Neural Network Parameter Mapping Structure  

Microsoft Academic Search

This paper discusses the Birl, an electronic wind instrument developed by the authors. It uses artificial neural nets to apply machine learning to the mapping of fingering systems and embouchure position. The design features of the instrument are described, and the machine learning mapping strategy is discussed.

Jeff Snyder; Danny Ryan

2014-01-01

265

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

E-print Network

speed felt by the turbine blades and the site-dependent air density which is related by a so-called power curve [3]. The output is maximised if the wind rotor is driven at an optimal rotational speed is a multi-input multi-output nonlinear model, and the difficulty of controlling it is mainly due to its

Pota, Himanshu Roy

266

Neural network theory based voltage and frequency controller for standalone wind energy conversion system  

Microsoft Academic Search

In this paper, a solid state voltage and frequency (VF) controller is proposed for a standalone wind energy conversion system (WECS) employing a permanent magnet synchronous generator (PMSG). The proposed VF controller consists of IGBTs (insulated gate bipolar transistors) based three-leg voltage source converter (VSC) with a battery energy storage system (BESS) at its dc link. The Adaline (adaptive linear

V. Sheeja; P. Jayaprakash; Bhim Singh; R. Uma

2010-01-01

267

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

268

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

269

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

270

Hour-ahead wind power and speed forecasting using market basket analysis and radial basis function network  

Microsoft Academic Search

Wind power is one of the most rapidly growing renewable energies for power generation nowadays. However, operation of power systems becomes challenging due to intermittent characteristics from wind energies. Consequently, effective wind power forecasting is crucial because of the economic consideration and operation. This paper presents a novel technique for short-term wind power and wind speed forecasting (1 hour ahead)

Ying-Yi Hong; Ching-Ping Wu

2010-01-01

271

Geology of Devils Tower National Monument, Wyoming  

USGS Publications Warehouse

Devils Tower is a steep-sided mass of igneous rock that rises above the surrounding hills and the valley of the Belle Fourche River in Crook County, Wyo. It is composed of a crystalline rock, classified as phonolite porphyry, that when fresh is gray but which weathers to green or brown. Vertical joints divide the rock mass into polygonal columns that extend from just above the base to the top of the Tower. The hills in the vicinity and at the base of the Tower are composed of red, yellow, green, or gray sedimentary rocks that consist of sandstone, shale, or gypsum. These rocks, in aggregate about 400 feet thick, include, from oldest to youngest, the upper part of the Spearfish formation, of Triassic age, the Gypsum Spring formation, of Middle Jurassic age, and the Sundance formation, of Late Jurassic age. The Sundance formation consists of the Stockade Beaver shale member, the Hulett sandstone member, the Lak member, and the Redwater shale member. The formations have been only slightly deformed by faulting and folding. Within 2,000 to 3.000 feet of the Tower, the strata for the most part dip at 3 deg - 5 deg towards the Tower. Beyond this distance, they dip at 2 deg - 5 deg from the Tower. The Tower is believed to have been formed by the intrusion of magma into the sedimentary rocks, and the shape of the igneous mass formed by the cooled magma is believed to have been essentially the same as the Tower today. Devils Tower owes its impressiveness to its resistance to erosion as compared with the surrounding sedimentary rocks, and to the contrast of the somber color of the igneous column to the brightly colored bands of sedimentary rocks.

Robinson, Charles Sherwood

1956-01-01

272

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

273

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

274

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.

275

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.

276

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

277

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

278

Oil well rig with water tower  

SciTech Connect

An oil well rig having a flotatable hull and support legs which are lifted and supported by the floating hull for moving the oil well rig and moved down to engage the sea bottom and jack up or raise the hull above the water at an operating site for drilling or servicing a well or serving an offshore well platform. A water tower has pipes longitudinally mounted by brackets on each side on a beam and is mounted for vertical movement in a well in the hull. An elevator mechanism mounted in the hull is employed to raise and lower the water tower which has guide means fitting a guide portion of the well to provide guided vertical movement of the water tower. When the water tower is lowered, a pump at the bottom of the pipe pumps sea water through the pipe to machinery on the hull to meet the water requirements of the machinery.

Younes, D. T.

1984-09-18

279

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

280

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

281

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

282

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

283

Study on dynamic optimum design of tower crane structure  

Microsoft Academic Search

The tower crane is a kind of construction machine which are widely used in the engineering construction, especially in modernized industry and civil construction. As the main skeleton of the tower crane, the design of the metal structure is very important for the operational reliability and the security of tower crane. The former design methods for tower crane structural were

Weihua Yang; Yourong Li; Zifan Fang; Kongde He

2011-01-01

284

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

285

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

286

Sequoias, Mavericks, Open Doors … Composing Joan Tower  

Microsoft Academic Search

:This essay interview with Joan Tower is a meditation on the importance of composing, understood as a process larger than the making of new sound combinations or musical scores, suggesting that the compositional act is self-educative and self-forming. Tower's musical life, one of teaching and learning, one of composing and self-composing, is an exemplary model for a lifetime of risk,

Randall Everett Allsup

2011-01-01

287

Sequoias, Mavericks, Open Doors … Composing Joan Tower  

Microsoft Academic Search

This essay interview with Joan Tower is a meditation on the importance of composing, understood as a process larger than the making of new sound combinations or musical scores, suggesting that the compositional act is self-educative and self-forming. Tower's musical life, one of teaching and learning, one of composing and self-composing, is an exemplary model for a lifetime of risk,

Randall Everett Allsup

2011-01-01

288

Soaring Towers: Building with Recycled Materials  

NSDL National Science Digital Library

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

Terc

2010-01-01

289

Rock Creek Tower Painting Project : Environmental Assessment.  

SciTech Connect

Bonneville Power Administration (BPA) built a 500-kV line across Rock Creek, a Class I trout stream about 20 miles east of Missoula, MT. Two 190-foot towers rise on either side of the Rock Creek valley, and the line between is suspended 600 feet over the valley floor. The crossing poses a hazard to passing airplanes and disrupts the natural landscape. The area where the line crosses Rock Creek is prized for its scenic beauty. In response to public demand that BPA protect the visual beauty of this area, BPA painted the towers gray to blend them best in with their natural surroundings. The issue now is to decide between either two gray towers or two orange-and-white towers. The underlying need is to resolve the conflict of pilot safety against scenic intrusion. The proposed action is to paint the gray tower aeronautical orange and white. Alternatives are to paint the orange-and-white tower back to its original gray; or leave the dilemma unresolved (the ''no-action'' alternative). 9 refs., 3 figs.

United States. Bonneville Power Administration.

1988-10-01

290

Which Way Will the Wind Blow? Networked Computer Tools for Studying the Weather.  

ERIC Educational Resources Information Center

A suite of networked computer tools within a pedagogical framework was designed to enhance earth science education at the high school level. These tools give students access to live satellite images, weather maps, and other scientific data dealing with the weather, and make it easy for students to make their own weather forecasts by creating…

Fishman, Barry J.; D'Amico, Laura M.

291

Which Way Will The Wind Blow? Networked Computer Tools For Studying The Weather  

Microsoft Academic Search

A suite of networked computer tools within a pedagogical framework was designed to enhance earth science education at the high school level. These tools give students access to live satellite images, weather maps, and other scientific data dealing with the weather, and make it easy for students to make their own weather forecasts by creating high-quality weather maps. These tools

Barry J. Fishman; Laura M. D'Amico

292

Study on structural effective life of tower crane and monitoring system for tower crane fleet based on systems engineering  

Microsoft Academic Search

This paper mainly study structural effective life of tower crane and tower crane fleet monitoring system from the aspects of optimization design, control and management based on system engineering. Firstly, tower crane working parameters were collected dynamically through wireless data transmission technology, whose feasibility has been tested to be good in experiments. Secondly, with improved RBF optimization algorithm, tower crane

Zheng Xi-jian; Lv Zhuan-zhen; Xie Zheng-yi

2010-01-01

293

Parametric study and dynamic analysis of compliant piled towers  

E-print Network

been brought to the public light clearly reflect the origin, design, tendencies and evolution of the compliant piled tower. The first structure of this nature was called the compliant tower jacket; it was designed by PMB Systems Engineering Inc, Mc... are structural elements that constrain the tower's horizontal motion at the mudline level, while allowing free rotntions. The skirt piles resist an important part of the shear forces generated in the tower by the environmental loads. The tower behaves as a...

Moog, Karl Heinz

2012-06-07

294

IMU Activities Tower Application and Contract 1 INDIANA MEMORIAL UNION STUDENT ACTIVITIES TOWER  

E-print Network

IMU Activities Tower Application and Contract 1 INDIANA MEMORIAL UNION STUDENT ACTIVITIES TOWER student organization, by its duly authorized officer, applies to rent space in the Indiana Memorial Union, events, or services that your organization sponsors for its members, students, and/or Indiana University

Indiana University

295

The effect of a tall tower on flow and dispersion through a model urban neighborhood: part 1. Flow characteristics.  

PubMed

Wind tunnel experiments were performed to examine the effect of a tall tower on the flow around an otherwise uniform array of buildings. Additionally, preliminary CFD simulations were run to visualize the flow with more resolution. The model used in both the wind tunnel and CFD studies was designed to simulate an area of Brooklyn, NY, USA, where blocks of residential row houses form a neighborhood bordering a major urban highway. This area was the site of a field study that, along with the work reported here, had the goal of improving the understanding of airflow and dispersion patterns within urban microenvironments. Results reveal that a tall tower has a dramatic effect on the flow in the street canyons in the neighboring blocks, enhancing the exchange between the street canyon flow and the freestream flow aloft. In particular, vertical motion down the windward side and up the leeward side of the tower resulted in strong flows in the lateral street canyons and increased winds in the street canyons in the immediate vicinity of the tower. These phenomena were visible in both the wind tunnel and CFD results, although some minor differences in the flow fields were noted. PMID:20024013

Heist, David K; Brixey, Laurie A; Richmond-Bryant, Jennifer; Bowker, George E; Perry, Steven G; Wiener, Russell W

2009-12-01

296

Titan 4B/Centaur/Cassini Service Tower Retract  

NASA Technical Reports Server (NTRS)

KENNEDY SPACE CENTER, FLA. -- At Launch Complex 40 on Cape Canaveral Air Station, the Mobile Service Tower has been retracted away from the Titan IVB/Centaur carrying the Cassini spacecraft and its attached Huygens probe. This is the second launch attempt for the Saturn-bound mission; a first try Oct. 13 was scrubbed primarily due to concerns about upper level wind conditions. Liftoff Oct. 15 is set to occur during a launch window opening at 4:43 a.m. EDT and extending until 7:03 a.m. Clearly visible in this view are the 66-foot-tall, 17-foot-wide payload fairing atop the vehicle, in which Cassini and the attached Centaur stage are encased, the two-stage liquid propellant core vehicle, and the twin 112-foot long solid rocket motor upgrades (SRMUs) straddling the core vehicle. It is the SRMUs which ignite first to begin the launch sequence.

1997-01-01

297

The Drop Tower Bremen -An Overview  

NASA Astrophysics Data System (ADS)

The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University of Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of ZARM`s drop tower began. Since its inau-guration in September 1990, the eye-catching Drop Tower Bremen with a height of 146m and its characteristic glass roof has become twice a landmark on the campus of the University of Bremen and the emblem of the technology park Bremen. As such an outstanding symbol of space science in Bremen the drop tower provides an european unique facility for experiments under conditions of high-quality weightlessness with residual gravitational accelerations in the microgravity regime. The period of maximum 4.74s of each freely falling experiment at the Drop Tower Bremen is only limited by the height of the drop tower vacuum tube, which was fully manufactured of steal and enclosed by an outer concrete shell. Thus, the pure free fall height of each microgravity drop experiment is approximately 110m. By using the later in-stalled catapult system established in 2004 ZARM`s short-term microgravity laboratory is able to nearly double the time of free fall. This world-wide inimitable capsule catapult system meets scientists` demand of extending the period of weightlessness. During the catapult operation the experiment capsule performs a vertical parabolic flight within the drop tower vacuum tube. In this way the time of microgravity can be extended to slightly over 9s. Either in the drop or in the catapult operation routine the repetition rates of microgravity experiments at ZARM`s drop tower facility are the same, generally up to 3 times per day. In comparison to orbital platforms the ground-based laboratory Drop Tower Bremen represents an economic alternative with a permanent access to weightlessness on earth. Moreover, the exceptional high quality of weightlessness in order of 1e-6 g (in the frequency range below 100Hz) demonstrates a perfect experimental environment for unperturbed investigations of scientific phenomena. Motivated by these prospects many national and international groups have initialized research programs taking advantage of this drop tower facility. In respect thereof the spectrum of research fields and technologies in space-related conditions can be continuously enhanced at ZARM. In the first of our two talks we will give you an overview about the inner structure of ZARM, as well as the service and the operation offered by the ZARM Drop Tower Operation and Service Company (ZARM FAB mbH). The ZARM FAB mbH owned by the State Government of Bremen is a public company maintaining the drop tower facility and supporting experimentalists in scientific and technical questions before, during and after their drop or catapult campaigns. In detail, we will present you important technical drop tower informations, our support and the idea, how you can proceed with your microgravity-related experiment including all your requirements to successfully accomplish an entire drop or catapult campaign. In summary, we will illustrate the complete procedure, how to drop or to catapult an experiment capsule at the Drop Tower Bremen.

von Kampen, Peter; Könemann, Thorben; Rath, Hans J.

298

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

299

CFD MODELING AND ANALYSIS FOR A-AREA AND H-AREA COOLING TOWERS  

SciTech Connect

Mechanical draft cooling towers are designed to cool process water via sensible and latent heat transfer to air. Heat and mass transfer take place simultaneously. Heat is transferred as sensible heat due to the temperature difference between liquid and gas phases, and as the latent heat of the water as it evaporates. Mass of water vapor is transferred due to the difference between the vapor pressure at the air-liquid interface and the partial pressure of water vapor in the bulk of the air. Equations to govern these phenomena are discussed here. The governing equations are solved by taking a computational fluid dynamics (CFD) approach. The purpose of the work is to develop a three-dimensional CFD model to evaluate the flow patterns inside the cooling tower cell driven by cooling fan and wind, considering the cooling fans to be on or off. Two types of the cooling towers are considered here. One is cross-flow type cooling tower located in A-Area, and the other is counterflow type cooling tower located in H-Area. The cooling tower located in A-Area is mechanical draft cooling tower (MDCT) consisting of four compartment cells as shown in Fig. 1. It is 13.7m wide, 36.8m long, and 9.4m high. Each cell has its own cooling fan and shroud without any flow communications between two adjacent cells. There are water distribution decks on both sides of the fan shroud. The deck floor has an array of about 25mm size holes through which water droplet falls into the cell region cooled by the ambient air driven by fan and wind, and it is eventually collected in basin area. As shown in Fig. 1, about 0.15-m thick drift eliminator allows ambient air to be humidified through the evaporative cooling process without entrainment of water droplets into the shroud exit. The H-Area cooling tower is about 7.3 m wide, 29.3 m long, and 9.0 m high. Each cell has its own cooling fan and shroud, but each of two corner cells has two panels to shield wind at the bottom of the cells. There is some degree of flow communications between adjacent cells through the 9-in gap at the bottom of the tower cells as shown in Fig. 2. Detailed geometrical dimensions for the H-Area tower configurations are presented in the figure. The model was benchmarked and verified against off-site and on-site test results. The verified model was applied to the investigation of cooling fan and wind effects on water cooling in cells when fans are off and on. This report will discuss the modeling and test results.

Lee, S.; Garrett, A.; Bollinger, J.

2009-09-02

300

Aerodynamic response analysis of wind turbines  

Microsoft Academic Search

Wind energy has received increasing attention in the same way as energy crisis and environmental deterioration. The aerodynamic\\u000a response of wind turbines is the major problem in wind turbine design. Blade element momentum theory was used to study the\\u000a aerodynamic thrusts of the blades on the tower. Iterative solutions were used to calculate the axial flow induction factor\\u000a for each

Jing Li; Jianyun Chen; Xiaobo Chen

2011-01-01

301

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

NASA Astrophysics Data System (ADS)

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

Seth, Raj Kumar

2010-07-01

302

Repair and completion of damaged cooling tower  

SciTech Connect

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 study was performed to insure that the completed tower would meet the design criteria. The repair plan involved repairing the cracks, sawing back the notch in a step fashion, refurbishing the scaffolding, rebuilding the gouged region, and then carrying the construction to completion. Also, two circumferential stiffening rings were added to the shell.

Gould, P.L. (Washington Univ., St. Louis, MO (United States). Dept. of Civil Engineering); Guedelhoefer, O.C. (Raths, Raths and Johnson, Inc., Willowbrook, IL (US))

1989-03-01

303

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

304

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

305

Wind Climate Analyses for SRTC's Central Climatology Site  

SciTech Connect

This report was written to present climatological summaries of the wind data at the Central Climatology (CC) tower in a convenient format and to point out some features of the wind speed and direction that have not been widely appreciated in the past. Short-term (two-week) wind roses provide a means to demonstrate the temporal and spatial relationships that wind speed and direction undergo using a ten-year database from the CC tower. These relationships are best demonstrated by examining the figures provided in this report or looking at loops of computer-generated images provided by the authors.

Weber, A.H.

2003-06-23

306

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

307

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

NASA Astrophysics Data System (ADS)

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

Takagi, Nobuyuki; Wang, Daohong

308

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

309

The new Drop Tower catapult system  

NASA Astrophysics Data System (ADS)

The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of the "Drop Tower" began. Since then, the eye-catching tower with a height of 146 m and its characteristic glass roof has become the emblem of the technology centre in Bremen. The Drop Tower Bremen provides a facility for experiments under conditions of weightlessness. Items are considered weightless, when they are in "free fall", i.e. moving without propulsion within the gravity field of the earth. The height of the tower limits the simple "free fall" experiment period to max. 4.74 s. With the inauguration of the catapult system in December 2004, the ZARM is entering a new dimension. This world novelty will meet scientists' demands of extending the experiment period up to 9.5 s. Since turning the first sod on May 3rd, 1988, the later installation of the catapult system has been taken into account by building the necessary chamber under the tower. The catapult system is located in a chamber 10 m below the base of the tower. This chamber is almost completely occupied by 12 huge pressure tanks. These tanks are placed around the elongation of the vacuum chamber of the drop tube. In its centre there is the pneumatic piston that accelerates the drop capsule by the pressure difference between the vacuum inside the drop tube and the pressure inside the tanks. The acceleration level is adjusted by means of a servo hydraulic breaking system controlling the piston velocity. After only a quarter of a second the drop capsule achieves its lift-off speed of 175 km/h. With this exact speed, the capsule will rise up to the top of the tower and afterwards fall down again into the deceleration unit which has been moved under the drop tube in the meantime. The scientific advantages of the doubled experiment time are obvious: during almost 10 s of high-quality weightlessness the range of compatible experiments amplifies even more and researchers can observe processes for a longer period of time. Thus, the new earth-bound laboratory of the ZARM offers unique conditions for scientific research. Moreover, it increases the attractiveness of the Drop Tower and contributes an important part to the establishment of the Bremen as an international centre for space technology.

von Kampen, Peter; Kaczmarczik, Ulrich; Rath, Hans J.

2006-07-01

310

Cooling Tower Considerations for Energy Optimizations  

E-print Network

of not providing a suffi- cient level of cold water. The clogged and corroded water distribution system was removed from the tower and the rusted, clogged, steel plate corrugated wet decking fill was also disposed of. After sandblasting and coating with coal... of not providing a suffi- cient level of cold water. The clogged and corroded water distribution system was removed from the tower and the rusted, clogged, steel plate corrugated wet decking fill was also disposed of. After sandblasting and coating with coal...

Burger, R.

1986-01-01

311

Carbon Fluxes in a Managed Landscape: Assessing the Drivers of Temporal and Spatial Variability in Flux Tower, MODIS and Forest Inventory Data of the Pacific Northwest  

NASA Astrophysics Data System (ADS)

This research focuses on the Wind Late Successional Reserve of Southern Washington where clear-cut logging over the past 100 years has created a fragmented landscape of coniferous forests that range in age from 0 to 500 years. In this study, we integrate several datasets to examine the environmental drivers of carbon exchange in this region across time and space. These sources include: (1) network of flux towers across a disturbance choronosequence, (2) MODIS Enhanced Vegetation Index, (3) aboveground net primary production (ANPP) from forest inventories, (4) and regional precipitation and air temperature measurements from the NOAA network of weather stations and PRISM reanalysis data. Net ecosystem exchange of carbon (NEE) has been measured at the Wind River Canopy Crane AmeriFlux site since 1998. The canopy crane is located in an old-growth forest composed of late seral Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla). Two flux towers were erected in early seral stands to study the effects of silviculture on net ecosystem exchange. CO2 uptake at the old-growth stand is highest in the spring before bud break when air and soil temperatures and vapor pressure deficit are relatively low, and soil moisture and light levels are favorable for photosynthesis, while maximum CO2 uptake is observed two to three months later at the early seral stands and coincide with peak leaf area index. This CO2 pattern is driven by different water conserving strategies. A reduction in carbon exchange is observed at the old-growth forest when moisture becomes limiting and canopy conductance rates drop sharply after mid-morning in the summer. In contrast, inhibition in canopy conductance rates and CO2 exchange is not observed at the early seral stands until soil moisture levels become critically low at the very end of the summer. The regional MODIS data (200 km X 200 km area) from 2000-2008 show that annual variability in the Enhanced Vegetation Index (EVI) also can be linked to precipitation and temperature anomalies at the stand level and across the region. Regional EVI anomalies are strongly negatively correlated with the annual precipitation and air temperature anomalies once the MODIS pixels are carefully examined with regards to forest age. EVI data from the tower-centered pixel also correlate well with annual NEE at the AmeriFlux site and show promise for scaling sparse flux tower observations, even over old-growth forests. Lastly, permanent plots have been continuously measured in the old-growth stand since 1947 and provide long-term data on tree demographics, recruitment, growth and mortality, and show evidence of decadal variability in response to precipitation and air temperature anomalies, as well as to disturbance (e.g., a Douglas-fir beetle kill in the 1950’s). We take advantage of the overlapping measurement period 1998-2004 and compare ANPP from the forest inventories to the flux tower estimates of NEE and MODIS EVI with focus on the regional environmental drivers.

Wharton, S.; Bible, K.; Falk, M.; Paw U, K.

2010-12-01

312

Distributed computation in wireless and dynamic networks  

E-print Network

Today's wireless networks tend to be centralized: they are organized around a fixed central backbone such as a network of cellular towers or wireless access points. However, as mobile computing devices continue to shrink ...

Oshman, Rotei

2012-01-01

313

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

314

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

315

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

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

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

316

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

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

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

317

14. WEST ELEVATION OF COAL TOWER No. 2, LOOKING WEST ...  

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

14. WEST ELEVATION OF COAL TOWER No. 2, LOOKING WEST TO EAST FROM COAL TOWER No. 1 (FLOOR BELOW THE CRANE CONTROL) - Delaware County Electric Company, Chester Station, Delaware River at South end of Ward Street, Chester, Delaware County, PA

318

15. VIEW OF COAL TOWER No. 2, LOOKING WEST TO ...  

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

15. VIEW OF COAL TOWER No. 2, LOOKING WEST TO EAST FROM COAL TOWER No. 1 (FLOOR BELOW CRANE CONTROL) - Delaware County Electric Company, Chester Station, Delaware River at South end of Ward Street, Chester, Delaware County, PA

319

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

320

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

321

4. Gate tower and access bridge, showing trash rack, with ...  

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

4. Gate tower and access bridge, showing trash rack, with lake level drawn down. View to northeast. - Keechelus Dam, Outlet Tower, Yakim River, 10 miles northwest of Easton, Easton, Kittitas County, WA

322

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

323

TOWER S389, MAGAZINES IN BACKGROUND. Naval Magazine Lualualei, West ...  

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

TOWER S389, MAGAZINES IN BACKGROUND. - Naval Magazine Lualualei, West Loch Branch, Guard-Watch Tower Type, Near A Avenue between Fourth & Sixth Streets, Ninth Street & D Avenue intersection, & F Avenue, Pearl City, Honolulu County, HI

324

TOWER S389, WITH POLE. MAGAZINES IN BACKGROUND. Naval Magazine ...  

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

TOWER S389, WITH POLE. MAGAZINES IN BACKGROUND. - Naval Magazine Lualualei, West Loch Branch, Guard-Watch Tower Type, Near A Avenue between Fourth & Sixth Streets, Ninth Street & D Avenue intersection, & F Avenue, Pearl City, Honolulu County, HI

325

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

326

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

327

Reconciling Latent and Sensible Energy Fluxes with Footprints in a Heterogeneous Landscape at an Urban-suburban Tower near Baltimore, Maryland  

NASA Astrophysics Data System (ADS)

Measurements of eddy-fluxes in an urban-suburban landscape may create technical difficulties as latent and sensible energy fluxes in the tower’s footprint are non-uniform. In an earlier study, we have found that the average vegetation cover surrounding the Cub Hill tower was 64 %; ranging from 46 to 77 % among 8 wind directions. We measured latent and sensible energy fluxes using a closed-path eddy-covariance system in the Cub Hill tower near Baltimore, Maryland. Half-hourly values of latent and sensible energy fluxes were stratified according to 24 15-degree bins of wind direction in each of the 16-day compositing periods for Normalized Difference Vegetation Index (NDVI) during 3 years of study (2004 to 2006). We used the daytime latent and sensible energy fluxes in the multivariate regression analyses to model fluxes of water vapor or evapotranspiration (ET) and sensible heat (H) as functions of micrometeorological variables (net radiation, temperature, relative humidity, wind speed, and soil moisture), NDVI, and land cover. Empirical models are developed at 16-day intervals for each of the 24 bins of wind direction to establish the relationships between energy fluxes (i.e., latent and sensible) and footprints (i.e., micrometeorology, NDVI, and land cover) around the Cub Hill tower.

Saliendra, N. Z.; Hom, J. L.; Pouyat, R. V.; Nowak, D.; Heisler, G. M.; Petterson, M.; Yesilonis, I.; Crawford, B.; Grimmond, S.

2009-12-01

328

Evaluation and quantification of the impact of cooling tower emissions on indoor air quality  

SciTech Connect

Assessment of the potential impact of outdoor pollutant sources on indoor air quality through the reentrainment of pollutants vis-a-vis air-handling units, doorways, and windows has mainly focused on the evaluation of fume hood, boiler, diesel generator, and vehicular pollutant emissions. In recent years, however, gaseous and waterborne pollutants emitted from cooling towers have become an increasing source of concern. Chemicals such as biocides and corrosion and scale inhibitors are used to reduce and/or eliminate algae blooms, decrease bacterial and fungal growth, and reduce the corrosion of equipment. When added to the water used in cooling towers, these chemicals are emitted in both the gaseous phase and as pollutants dissolved in or suspended in water droplets. A qualitative evaluation of exhaust dispersion and droplet deposition rates associated with cooling towers is necessary when conducting an overall review of the environmental impact on indoor air quality. This paper identifies source emission rates to be used in assessing emissions of chemical additives in cooling towers, presents provisional design criteria for evaluating the impact of the chemical additives, and evaluates alternative methodologies for quantifying impact concentrations. These alternative assessment methodologies include numerical models, physical wind tunnel simulations, and computational fluid dynamics (CFD) simulations. Parameters used in comparing the methodologies include relative accuracy (order of magnitude) and modeling and simulation limitations.

Vanderheyden, M.D.; Schuyler, G.D. [Rowan Williams Davies and Irwin, Inc., Guelph, Ontario (Canada)

1994-12-31

329

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

330

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

331

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

332

How cooling towers affect process energy savings  

Microsoft Academic Search

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

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

1984-01-01

333

Failure Analysis of the Tower Crane Counterjib  

Microsoft Academic Search

Failures of the cranes’ structural parts unavoidably lead to serious damages or total collapses; these accidents are often followed by very high financial losses and possibly serious injuries or crane-related fatalities. The objective of this research was to identify the causes that led to the failure of the hammerhead tower crane (xl425C) counterjib. The crane is used for assembly works

Nenad D. Zrnic; Srdan M. Bosnjak; Vlada M. Gasic; Miodrag A. Arsic; Zoran D. Petkovic

2011-01-01

334

Special purpose simulation modeling of tower cranes  

Microsoft Academic Search

Historically, simulation tools have only been used and understood by the academic community. Special purpose simulation (SPS) techniques have introduced computer modeling to the industry, resulting in reduced model development time and a user-friendly environment. This paper describes the special purpose simulation template, which is based on the tower crane operations performed by PCL Constructors Incorporated. On-site management of the

Bradford J. A. Appleton; J. Patra; Y. Mohamed; S. AbourRizk

2002-01-01

335

THE EXAMPLE THE TOWER OF HANOI  

E-print Network

-BOOTLE, Devil's DP Dictionary This program represents one ofthe few examples ofagreement in computer science is no excep- tion. The Tower of Hanoi is based on a game (popular in the 1960s) that had its own mythology (also popular in the 1960s): An ancient myth has it that in some temple in the Far East, time is marked

Ducasse, Stéphane

336

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...

337

Queensland University of Technology Drop Tower Facility  

NASA Astrophysics Data System (ADS)

The Queensland University of Technology (QUT) Drop Tower Facility provides access to an inexpensive high quality reduced gravity test environment. This facility is available to and has been used by number of nationally and internationally based organisations, along with researchers from QUT, for scientific and industry related research. The drop tower, located in Brisbane, Australia, allows 2.0 seconds of high quality reduced gravity (˜0.001 g). The cylindrical drop package has a maximum rating of 200 kg with dimensions of 0.8 m diameter and 0.9 m high, and experiences a maximum deceleration of ˜30 g. Current research projects being carried out at the QUT Drop Tower Facility include research in the areas of self-propagating high-temperature synthesis of materials, combustion and fire safety, flammability of metals, characterisation of combustion products, and sol-gel nanomaterials. Keywords: Reduced gravity, microgravity, drop tower, zero gravity, low gravity, combustion, combustion products, nanomaterials, sol-gel, flammability, high temperature synthesis.

Plagens, Owen; Hales, Matthew; Castillo, Martin; Steinberg, Theodore

2012-07-01

338

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

339

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.

340

Tower Crane Effective Life Assessment Based on Tower Crane Fleet Monitoring System  

Microsoft Academic Search

\\u000a How to obtain and make full use of reliable working information of tower crane fleet effectively is still a problem. Here,\\u000a a monitoring system was built to help acquire tower crane working parameters and assess effective life. Firstly, based on\\u000a Visual Basic and SQL Server technology, parameters were collected through wireless transmission, and then classified, saved\\u000a and processed to get

Zeguang Han; Min Hu; Xinfang Song; Ruiqing Hao; Xijian Zheng

2010-01-01

341

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

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

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

342

APDL language-based optimization of tower crane  

Microsoft Academic Search

Optimization design of tower crane steel structure is very important for design technique development of tower crane. This paper proposes a kind of parametric optimization model based on Ansys OPT, combined with finite element analysis (FEA) and overall stability theory. The tower body is taken as an example to introduce the building process and the program structure of the parametric

Song Shijun; Li Lei; Wang Jiyong; Mao Ruinian

2010-01-01

343

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

344

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWERS THREE AND FOUR ...  

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

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWERS THREE AND FOUR WITH TOWERS FIVE AND SIX IN THE DISTANCE, LOOKING NORTHEAST. THE TWO INTACT CABLES RUNNING ALONG TOP OF THE TOWERS ARE FIXED. WHILE THE MOVING CABLE IS LYING SLACK ON THE GROUND. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

345

36 CFR 7.30 - Devils Tower National Monument.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Devils Tower National Monument. 7.30 Section...THE NATIONAL PARK SYSTEM § 7.30 Devils Tower National Monument. (a) Climbing...any climbing above the talus slopes on Devils Tower. The registrant is also...

2010-07-01

346

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

347

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

348

Initial Model For Fires In The World Trade Center Towers  

Microsoft Academic Search

Based on preliminary assumptions and analysis, mathematical models have been used to estimate the behavior of the fires in the twin towers of the World Trade Center (WTC) on September 11, 2001. The hijacked-plane collision with each tower produced significant structural damage, generated a spectacular external fireball, and started burning within the tower. The fuel consumed by the fireball was

Ronald G. Rehm; William M. Pitts; Howard R. Baum; David D. Evans; Kuldeep Prasad; Kevin B. McGrattan; Glenn P. Forney

2003-01-01

349

7th International Workshop on Large Scale Integration of Wind Power and on Transmission Networks for Offshore Wind Farms Impacts of large amounts of wind power on design and operation of power systems, results of IEA collaboration  

E-print Network

Abstract — There are a multitude of studies made and ongoing related to cost of wind integration. However, the results are not easy to compare. An international forum for exchange of knowledge of power system impacts of wind power has been formed under the

Hannele Holttinen; Peter Meibom; Antje Orths; Bart C. Ummels; John Olav T; Ana Estanqueiro; Emilio Gomez; J. Charles Smith; Erik Ela

350

Synchronization of the ERDA-NASA 100 kW wind turbine generator with large utility networks  

NASA Technical Reports Server (NTRS)

The synchronizing of a wind turbine generator against an infinite bus under random conditions is studied for the first time. With a digital computer, complete solutions for rotor speed, generator power angle, electromagnetic torque, wind turbine torque, wind turbine blade pitch angle, and armature current are obtained and presented by graphs. Experiments have been recently performed on the ERDA-NASA 100 kW wind turbine. Experimental results matched computer study results very closely and confirmed that the synchronization can be accomplished by means of the existing speed control system and an automatic synchronizer.

Hwang, H. H.; Gilbert, L. J.

1977-01-01

351

The Drop Tower Bremen -Experiment Operation  

NASA Astrophysics Data System (ADS)

The idea behind the drop tower facility of the Center of Applied Space Technology and Micro-gravity (ZARM) in Bremen is to provide an inimitable technical opportunity of a daily access to short-term weightlessness on earth. In this way ZARM`s european unique ground-based microgravity laboratory displays an excellent economic alternative for research in space-related conditions at low costs comparable to orbital platforms. Many national and international ex-perimentalists motivated by these prospects decide to benefit from the high-quality and easy accessible microgravity environment only provided by the Drop Tower Bremen. Corresponding experiments in reduced gravity could open new perspectives of investigation methods and give scientists an impressive potential for a future technology and multidisciplinary applications on different research fields like Fundamental Physics, Astrophysics, Fluid Dynamics, Combus-tion, Material Science, Chemistry and Biology. Generally, realizing microgravity experiments at ZARM`s drop tower facility meet new requirements of the experimental hardware and may lead to some technical constraints in the setups. In any case the ZARM Drop Tower Operation and Service Company (ZARM FAB mbH) maintaining the drop tower facility is prepared to as-sist experimentalists by offering own air-conditioned laboratories, clean rooms, workshops and consulting engineers, as well as scientific personal. Furthermore, ZARM`s on-site apartment can be used for accommodations during the experiment campaigns. In terms of approaching drop tower experimenting, consulting of experimentalists is mandatory to successfully accomplish the pursued drop or catapult capsule experiment. For this purpose there will be a lot of expertise and help given by ZARM FAB mbH in strong cooperation to-gether with the experimentalists. However, in comparison to standard laboratory setups the drop or catapult capsule setup seems to be completely different at first view. While defining a microgravity project at the Drop Tower Bremen, interesting experimentalists should keep in mind generally reducing dimensions and masses of their common laboratory setups to meet the capsule constraints: overall payload height 980mm/1730mm (short/long drop capsule) and 950mm (catapult capsule); area of each capsule platform 0,359sqm; maximum payload mass 274kg/234kg (short/long drop capsule) and 163,8kg (catapult capsule). The base equipments of each capsule are the Capsule Control System (CCS) to remote control the experiment and the rechargeable battery pack (24V/40A) for the experiment operation. Moreover, the exper-iment components must be able to withstand maximum decelerations of 50g while the short capsule impact of about 200ms, and maximum accelerations of 30g while catapult launch with a duration of about 300ms. In our second talk concerning ZARM`s drop tower facility we will go on with detailed infor-mations about the technical base setups of the drop and the catapult capsule structure to completely handle a freely falling experiment. Furthermore, we will summarize interesting current drop tower projects as an outlook to present you the range of opportunities at the ground-based short-term microgravity laboratory of ZARM.

Könemann, Thorben; von Kampen, Peter; Rath, Hans J.

352

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

353

An automatic and effective approach in identifying tower cranes  

NASA Astrophysics Data System (ADS)

A method which can distinguish tower cranes from other objects in an image is proposed in this paper. It synthesizes the advantages of both morphological theory and geometrical characters to identify tower cranes accurately. The algorithm uses morphological theory to remove noise and segment images. Moreover, geometrical characters are adopted to extract tower cranes with thresholds. To test the algorithm's practical applicability, we apply it to another image to check the result. The experiments show that the approach can locate the position of tower cranes precisely and calculate the number of cranes at 100% accuracy rate. It can be applied to identifying tower cranes in small regions.

Yu, Bo; Niu, Zheng; Wang, Li; Liu, Yaqi

2012-04-01

354

Design considerations for a fiberglass, field erected, closed-circuit cooling tower  

SciTech Connect

The paper contains a review of the major design differences between closed-circuit cooling towers in which the air and water streams flow essentially parallel and other more conventional field erected cooling products used for steam condensing, water cooling and other heat rejection applications. Guidelines for the selection of composite and non-composite materials of construction are presented. The structural design considerations for dead, wind and vibrational loads and those required for field erection are offered based on the experience obtained by constructing what is believed to be the world`s first fiberglass, field built, closed-circuit cooling tower. The technical review of the various design considerations is supplemented by the author`s practical experience with installations constructed of pultruded fiberglass composites, steel and concrete which provides a unique practical perspective to this paper.

Carlson, C.W. [Baltimore Aircoil Co., MD (United States). Product Engineering Dept.

1998-12-31

355

Influence of Flow Rotation Within a Cooling Tower on the Aerodynamic Interaction with Crosswind Flow  

NASA Astrophysics Data System (ADS)

Environmental crosswind changes the aerodynamic pattern inside a cooling tower, destroys uniform and axisymmetric distribution of flow at its inlet and outlet, and may degrade fill zone performance. In this paper, the effect of flow rotation in the over-shower zone of a natural draft cooling tower (NDCT) on the aerodynamic interaction with crosswind is studied numerically. The 3D geometry of an actual NDCT and three models of induced rotation velocity fields are utilized for simulation. It is demonstrated that flow rotation results in homogenization of the aerodynamic field in the over-shower zone. The inhomogeneity of the velocity field in the outlet cross section decreases linearly with rotation intensification. The effect of main stream switching under strong wind conditions is found. It is shown that even moderate flow rotation eliminates this effect.

Kashani, M. M. Hemmasian; Dobrego, K. V.

2014-03-01

356

Pilot projects of network wind power plants in the eisk region of Krasnodar krai: the state and prospects  

NASA Astrophysics Data System (ADS)

The market of electric energy in the Krasnodar krai and the specific features of electric power supply in the Eisk region are analyzed. The basic aspects of designing wind power plants are considered. The main technical, economic, and environmental indicators of the wind power plants being designed are presented.

Gordeev, I. G.; Ermolenko, G. V.; Nikomarova, A. V.; Ryzhenkov, M. A.; Tskhomariya, V. N.

2012-11-01

357

A low-delay medium access control mechanism of WSN for tower crane group  

Microsoft Academic Search

A MAC protocol-wake up one by one MAC (WOO-MAC) for the tower crane group monitoring control system based on WSN (Wireless Sensor Network) is proposed in the paper, which can get low-delay and low-energy consumption. WOO-MAC solves the data forward intermit effectively, which exists in most active\\/sleep protocols, by waking up the nodes in the data collecting tree one by

Yue Zhou; Xijian Zheng; Shuai Liu; Bo Li

2011-01-01

358

NOVA Online: Why the Towers Fell  

NSDL National Science Digital Library

Why the Towers Fell is a special episode of NOVA scheduled for broadcast on PBS on April 30, 2002. This online material complements the television program by assessing the exact cause of the disaster from an engineer's standpoint. One section of the Web site is an interview with a materials engineering professor from the Massachusetts Institute of Technology. In the dialog, he describes the most probable reasons for the towers' collapse and some building safety improvements that can be made in the future. There are two multimedia features on the site: one explores the structure of metal while the other looks at firefighter equipment. A particularly moving account of the Trade Center collapse comprises another section, from one of only four people who escaped from above the floors where either plane hit.

2002-01-01

359

Linearized aeroelastic analysis of a wind turbine with a two-bladed rotor  

Microsoft Academic Search

The coupled, linearized system tower-rotor of a wind turbine with horizontal axis and asymmetric rotor was investigated. The equations of motion of the linearized system were deduced. The displacements of tower and rotor are described. Linearized, quasistationary aerodynamic loads were taken into account. The structure and modal analysis of the isolated partial systems are described using finite element program systems.

Bertold Kirchgaessner

1986-01-01

360

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

E-print Network

technique was investigated to assess its ability to detect surface flaws on an on-tower wind turbine blade% of the total turbine cost and maintenance poses significant challenges due to the scale, on-tower location.g., cranes) and skilled technicians [4]. Early inspection can help prevent severe structural damage

McCalley, James D.

361

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

362

Early operation experience on the ERDA/NASA 100 kW wind turbine. [rotor blade loads  

NASA Technical Reports Server (NTRS)

As part of the Energy Research and Development Administration (ERDA) wind energy program, NASA Lewis Research Center is testing an experimental 100-kW wind turbine. Rotor blade and drive shaft loads and tower deflection were measured during operation of the wind turbine at rated rpm. The blade loads measured are higher than anticipated. Preliminary results indicate that air flow blockage by the tower structure probably caused the high rotor blade bending moments.

Glasgow, J. C.; Linscott, B. S.

1976-01-01

363

GA-ANN model for optimizing the locations of tower crane and supply points for high-rise public housing construction  

Microsoft Academic Search

Site layout planning is a complicated issue due to the existence of a vast number of trades and inter-related planning constraints. In this paper, artificial neural networks are used to model the non-linear operations of a key site facility: a tower crane — for high-rise public housing construction. Then genetic algorithms are used to determine the locations of the tower

C. M. Tam; Thomas K. L. Tong

2003-01-01

364

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...

365

Dynamics and control of horizontal axis wind turbines  

Microsoft Academic Search

This tutorial paper describes the field of wind turbine control. It begins with the simplest turbine dynamic models and progresses to more advanced models which incorporate structural resonances in the blades and supporting tower. Disturbance accommodating control techniques are used to provide power control in fluctuating wind fields.

Mark J. Balas; Alan Wright; M. Hand; K. Stol

2003-01-01

366

Load response of horizontal-axis wind turbines to turbulence  

Microsoft Academic Search

A structural and aerodynamic model of a three-bladed rigid-hub wind turbine is described. The model includes four structural degrees of freedom; one for each blade in flapping, and tower translation. The aerodynamic model includes the effects of wind turbulence as well as the unsteady aerodynamic effects caused by the airfoil shed and trailing wakes. A separate code developed at the

R. E. Wilson; S. N. Walker; J. R. Hartin; T. L. Weber

1990-01-01

367

Horizontal axis wind turbine systems: optimization using genetic algorithms  

Microsoft Academic Search

A method for the optimization of a grid-connected wind turbine system is presented. The behaviour of the system components is coupled in a non-linear way, and optimization must take into account technical and economical aspects of the complete system design. The annual electrical energy cost is estimated using a cost model for the wind turbine rotor, nacelle and tower and

T. Diveux; P. Sebastian; D. Bernard; J. R. Puiggali; J. Y. Grandidier

2001-01-01

368

Predict particle collection in spray towers  

SciTech Connect

Spray tower wet scrubbers are used for control of particulates (as well as gaseous pollutants). The author has found that in cocurrent spray scrubbers, the most important parameter in determining particle collection efficiency is inlet dust particle size, followed by (in decreasing order of importance) gas velocity, collector droplet size, liquid-to-gas ratio, and length of scrubber. In countercurrent scrubbers, the most important parameters are collector droplet size, liquid-to-gas ratio, length of scrubber, and gas velocity. Note that some of these factors are directly related to collection, and some are related indirectly. This article provides equations, based on theoretical considerations and empirical data, for predicting particle collection efficiencies. The parameter ranges covered are typical of those encountered in the practical operation of conventional spray towers that use a ``cool`` (or cooled) inlet gas stream, so the equations are applicable to many industrial spray tower systems. The results are limited based on the ranges of the parameters evaluated, and while it may be possible to extrapolate beyond that, this has not been verified. (The initial model was for a flue-gas desulfurization system at a large power station that requires both particulate removal and SO{sub 2} absorption.)

Hesketh, H.E. [Southern Illinois Univ., Carbondale, IL (United States)

1995-10-01

369

A compliant tower design for mild environments  

SciTech Connect

The compliant tower type of offshore platform is a bottom-fixed structure that is basically the same as the traditional steel ``Fixed Platform.`` However, the compliant tower is intended for deepwater application and is configured to be very much more compliant. It can thereby greatly reduce the effect of waveloads. Consequently, it can provide an economical platform in much deeper water-depths than the traditional fixed platform. Over at least the past two decades, numerous variations based on the principle of compliance have been developed to greater or lesser detail. This paper describes a particular design for mild environments as typified by offshore West Africa, for example. Relative to the designs deemed appropriate for somewhat more severe environments such as the Gulf of Mexico, the structure is significantly simplified, and can achieve substantial reductions in materials. Some performance data for the mild environment design is described and discussed, with some comparisons to other environments and the conventional fixed platform. For mild environments, the compliant tower appears particularly attractive in that it can offer the safety and reliability of a fixed platform operation, combined with very significant savings in materials and construction.

Reusswig, G.H.; Nair, V.V. [Mobil Research and Development Corp., Dallas, TX (United States). Dallas E and P Engineering

1994-12-31

370

Water-conserving cooling tower treatment  

SciTech Connect

Water conservation in cooling towers and evaporative coolers can finally become a reality. Also, fouled closed hot and chilled water systems can be restored to near original efficiency using the same technology. The barrier limiting the traditional water treatment industry from serious involvement in water conservation is the lack of a really good chemical to control scale. Poor scale inhibitors are the reason for a heavy bleed. Minerals concentrated by evaporation is wasted to the sewer while low solids make-up water fills the tower. Water conservation is important because of the increasing usable water shortage, the cost to add infrastructure to deliver increasing amounts of water to accommodate growth and the limitations imposed on disposal to the sewer. Now, due to innovations in chemical treatment, users of cooling towers and evaporative coolers can conserve water. In this presentation the author assumes the audience has some knowledge of traditional water treatment. Except for a few general references to establish common understanding, the author confines his remarks to discussing an advanced technology developed by DIAS, Inc., and the economics of its use.

Mathie, A.J. [A.J. Mathie Company, Roy, UT (United States)

1996-12-31

371

Legionella spp. in Puerto Rico cooling towers  

SciTech Connect

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

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

1988-10-01

372

Aspects of cooling tower biocides and protozoa  

SciTech Connect

Previous work has shown that certain cooling tower amoebae and ciliated protozoa are resistant to several cooling tower biocides, even at the manufacturer`s recommended dosages. For the present study, an Acunthumoeba species was isolated from a cooling tower in Australia. Suspensions of the trophozoites (feeding stages) were exposed to isothiazolones. Cysts were tested separately. The minimum lethal concentration (MLC) for trophozoites was between 31-62 ppm of the biocide product, which is slightly less than the MLC for an amoebae species from the United States; and cyst forms were twofold more resistant than those of the US species, with a MLC of 62,500 ppm. A ciliate and an amoeba species were also exposed to bromochlorodimethylhydantoin. The MLC for the ciliate species was 1 ppm of the biocide product, and the MLC was 30--40 ppm for the amoeba trophozoites. Since amoebae can expel vesicles containing live Legionella, experiments were conducted to determine whether exposure of Acunthamoebu polyphugu to biocides influenced release of such potentially infectious particles. Vesicle release was not inhibited by any of the three biocides: quaternary ammonium compounds (QACs), isothiazolones, and a thiocarbamate compound. These results suggest that amoebae from various sources are resistant to recommended levels of biocides, and the amoebae may continue to release potentially infectious vesicles in the presence of biocides.

Berk, S.G.; Ashburn, R.J.; Ting, R.S. [Tennessee Technological Univ., Cookeville, TN (United States). Center for the Management, Utilization and Protection of Water Resources

1998-12-31

373

Legionella in Puerto Rico cooling towers  

SciTech Connect

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

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

1988-12-31

374

Wind energy systems  

NASA Astrophysics Data System (ADS)

Wind energy has matured to a level of development where it is ready to become a generally accepted utility generation technology. A brief discussion of this development is presented, and the operating and design principles are discussed. Alternative designs for wind turbines and the tradeoffs that must be considered are briefly compared. Development of a wind energy system and the impacts on the utility network including frequency stability, voltage stability, and power quality are discussed. The assessment of wind power station economics and the key economic factors that determine the economic viability of a wind power plant are presented.

Richardson, R. D.; McNerney, Gerald M.

1993-03-01

375

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

376

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

377

ValidWind applications: wind power prospecting, aerosol transport  

NASA Astrophysics Data System (ADS)

The ValidWind™ system employs an XL200 laser rangefinder to track small, lightweight, helium-filled balloons (0.33 meters, 0.015 kg). We record their trajectories (range resolution 0.5 meters) and automatically produce local wind profiles in real time. Tracking range is enhanced beyond 2 km by applying retro-reflector tape to the balloons. Aerodynamic analysis shows that ValidWind balloon motion is well coupled to the local wind within relaxation times { 1 second, due to drag forces at subcritical Reynolds numbers Re < 2×105. Such balloons are Lagrangian sensors; i.e., they move with the wind as opposed to being fixed in space. In a field campaign involving many balloons, slight variations in ground level winds at launch lead to trajectory patterns that we analyze to derive 3D maps of the vertical and horizontal wind profiles downwind of the launch area. Field campaigns are focused on likely sites for wind power generation and on facilities from which airborne particulates are emitted. We describe results of wind measurements in Utah near the cities of Clarkston, Logan, and Ogden. ValidWind is a relatively inexpensive wind sensor that is easily and rapidly transported and deployed at remote sites. It is an ideal instrument for wind prospecting to support early decisions required, for example, in siting meteorology towers. ValidWind provides high-resolution, real time characterization of the average and changing 3D wind fields in which wind power turbines and other remote sensors must operate.

Wilkerson, T.; Marchant, A.; Apedaile, T.; Scholes, D.; Simmons, J.; Bradford, B.

2010-10-01

378

Radar cross section dependence on wind speed  

Microsoft Academic Search

YSCAT was an ultrawideband (2-20 GHz), near constant beamwidth scatterometer intended to provide radar cross section measurements at varying radar and environmental parameters. YSCAT was deployed on the CCIW (Canada Center for Inland Waters) tower on Lake Ontario for a period of six months in 1994. Using YSCAT data, this paper reports (1) observance of a “low wind-speed cutoff”, the

David G. Long; Ben E. Barrowes; David V. Arnold

1999-01-01

379

Research results for the Tornado wind energy system: analysis and conclusions  

Microsoft Academic Search

The Tornado Wind Energy System (TWES) concept utilizes a wind-driven vortex confined by a hollow tower to create a low-pressure core intended to serve as a turbine exhaust reservoir. The turbine inlet flow is provided by a separate ram air supply. Numerous experimental and analytical research efforts have investigated the potential of the TWES as a wind energy conversion system

E. W. Jacobs

1985-01-01

380

Research results for the tornado wind-energy system: Analysis and conclusions  

Microsoft Academic Search

The Tornado Wind Energy System (TWES) concept utilizes a wind driven vortex confined by a hollow tower to create a low pressure core intended to serve as a turbine exhaust reservoir. The turbine inlet flow is provided by a separate ram air supply. Numerous experimental and analytical research efforts investigated the potential of the TWES as a wind energy conversion

E. Jacobs

1983-01-01

381

Structural health monitoring of wind turbines using fiber Bragg grating based sensing system  

Microsoft Academic Search

As the size of wind turbines increases, the early detection of structural instability becomes increasingly important for safety. This paper introduces a fiber Bragg grating-based sensing system for use in multi-MW scale wind turbine health monitoring, and describes the results of preliminary field tests of dynamic strain monitoring of the tower structure of an onshore wind turbine. For this research,

Hyung-Joon Bang; Moonseok Jang; Hyungki Shin

2011-01-01

382

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

NASA Astrophysics Data System (ADS)

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

Siuta, David

383

Plant Light Stress Tolerance across the New Mexico Elevation Gradient: Scaling from Leaf to Tower  

NASA Astrophysics Data System (ADS)

Excess light is a major abiotic component of plant stress especially when combined with sustained periods of drought. Arid and semi-arid ecosystems are regularly exposed to sustained high light, low water conditions. A network of nine Eddy Covariance towers oriented along an elevation gradient in central New Mexico has been utilized to assess differences in light use efficiency and light stress response across six distinct biomes, all of which are subjected to a semi-arid climate regulated by a seasonal monsoon. Leaf level measurements of effective quantum yield (?PSII ) and non-photochemical quenching (NPQ) parameters were taken at five of these biomes pre and post monsoon using branch mounted and hand held pulse amplitude modulated (PAM) fluorometers. Diurnal samples of leaf tissue were snap frozen to be analyzed for xanthophyll de-epoxidation state via high pressure liquid chromatography. We analyzed these leaf level parameters in the context of tower based and satellite derived measurements of NDVI, PRI and eddy covariance measures of ecosystem function including net ecosystem exchange and light use efficiency. This multi-biome, multi-scale approach aims to investigate not only leaf level photochemical response to excess light, but also how these responses are perceived by remote sensing platforms at flux tower and low earth orbit scales. We hypothesize that plant photochemical status with respect to light use efficiency and excess light mitigation strategies fluctuates as a function of elevation and the seasonal monsoon. We expect to see the highest regulatory capacity at low elevation, low precipitation sites. The NDVI and PRI signal from the tower level will track changes in ecosystem function with respect to NEE and be explained by differences in the ability of biome specific plant functional types to deal with excess light. The tower footprint, parameterized by plant functional type constituents, will be scaled to the landscape level by analysis of MODIS products.

Krofcheck, D. J.; Hanson, D.; Fox, A. M.; Litvak, M. E.

2010-12-01

384

Gust Buffeting and Aeroelastic Behaviour of Poles and Monotubular Towers  

NASA Astrophysics Data System (ADS)

The evolution in the constructional field and the realization of ever more slender and light structures have emphasized the increasing difficulty of properly evaluating the actions and effects of wind on poles and monotubular towers. Faced with this situation the Italian constructors, united in a consortium coordinated by ACS ACAI Servizi, entrusted the Department of Structural and Geotechnical Engineering of Genova University with the task of formulating an ad hoc calculation procedure for this type of structure. This gave rise to a wide-ranging research project in which theoretical models, experimental evaluations and engineering methods were developed in parallel through an effective and quite a unique co-operation between researchers, designers and builders. This paper illustrates the physical aspects, the general principles and the basic formulation of the method proposed, with special emphasis on gust buffeting and aeroelastic phenomena. Preliminary results of full-scale measurements of the structural damping are also presented. The conclusions highlight the scientific and technical perspectives of this research.

Solari, G.; Pagnini, L. C.

1999-10-01

385

Radiation scanning aids tower diagnosis at Arun LNG plant  

SciTech Connect

Radiation scanning has been used effectively to troubleshoot the treating towers of the Arun LNG plant in Sumatra, Indonesia. The plant is one of the world's largest such facilities. The analysis was part of an investigation aimed at increasing the capacity of the treater section of the plant. Radiation scanning is a tool which, in addition to tower differential pressure and product purity, can aid in diagnosing tower performance.

Naklie, M.M. (Mobil Exploration and Producing Services Inc., Dallas, TX (US)); Pless, L. (Tru-Tec Inc., Houston, TX (US)); Gurning, T.P.; Hyasak, M. (P.T. Arun Natural Gas Liquefaction Co., Sumatera (USA))

1990-03-26

386

10. Photocopy of photograph of tower as constructed at Cape ...  

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

10. Photocopy of photograph of tower as constructed at Cape Henlopen, Delaware, September 1926 (original photograph in National Archives and Records Service, Still Pictures Branch, RG 26, 26-LG-22-A), photographer G.W. Hitchens, September 10, 1926. "New Tower. Camera Station West 100 ft." - Mispillion Lighthouse, Beacon Tower, South bank of Mispillion River at it confluence with Delaware River at northeast end of County Road 203, 7 miles east of Milford, Milford, Sussex County, DE

387

No Chemical, Zero Bleed Cooling Tower Water Treatment Process  

E-print Network

NO CHEMICAL, ZERO BLEED COOLING TOWER WATER TREATMENT PROCESS ALDEN L. COKE, CWS IV, PRESIDENT, AQUA-FLO, INC., BALTIMORE, MARYLAND ABSTRACT This paper describes a process to treat cooling tower water by means of a fully automated... and chemical free mechanical water treatment process. This is an alternative to conventional chemical treatment. Beginning with a suction pump to draw water out of the tower sump, water goes through a permanent magnetic descaler to increase the water...

Coke, A. L.

388

Power coefficient of tornado-type wind turbines  

SciTech Connect

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

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

1983-11-01

389

Solar power tower development: Recent experiences  

SciTech Connect

Recent experiences with the 10 MW{sub e} Solar Two and the 2.5 MW{sub t} TSA (Technology Program Solar Air Receiver) demonstration plants are reported. The heat transfer fluids used in these solar power towers are molten-nitrate salt and atmospheric air, respectively. Lessons learned and suggested technology improvements for next-generation plants are categorized according to subsystem. The next steps to be taken in the commercialization process for each these new power plant technologies is also presented.

Tyner, C.; Kolb, G.; Prairie, M. [and others

1996-12-01

390

Untapped Energy Savings from Cooling Towers  

E-print Network

of service if it causes the main header pipe to fail. An annual inspection should identify any framing members are in bad shape, and avoid this problem. Towers that have film fill (Figure 4) can be subject to fouling. The smaller the corrugation... in film sheet the easier the film fill can foul. The corrugation size usually ranges from1/2? to the size you can practically drop a golf ball through. It?s sometimes hard to see if film fill has fouled, and you have to look for other signs. One...

Phelps Jr., P.

2011-01-01

391

The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers  

SciTech Connect

Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understanding the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative 'dry' cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered.

Abedi-Nik, Farhad [SADRA Institute of Higher Education, Tehran (Iran, Islamic Republic of); Sabouri-Ghomi, Saeid [K.N.T University of Technology, Tehran (Iran, Islamic Republic of)

2008-07-08

392

2. HI PAR (ACQUISITION RADAR) TOWER AND ENLISTED MEN (EM) ...  

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

2. HI PAR (ACQUISITION RADAR) TOWER AND ENLISTED MEN (EM) BARRACKS WITH RADAR ATTACHED. - Nike Hercules Missile Battery Summit Site, Battery Control Administration & Barracks Building, Anchorage, Anchorage, AK

393

Optimal Inflatable Space Towers with 3 - 100 km Height  

NASA Technical Reports Server (NTRS)

Theory and computations are provided for building inflatable space towers up to one hundred kilometers in height. These towers can be used for tourism, scientific observation of space, observation of the Earth's surface, weather and upper atmosphere, and for radio, television, and communication transmissions. These towers can also be used to launch space ships and Earth satellites. These projects are not expensive and do not require rockets. They require thin strong films composed from artificial fibers and fabricated by current industry. The towers can be built using present technology. The towers can be used (for tourism, communication, etc.) during the construction process and provide self-financing for further construction. The tower design does not require work at high altitudes; all construction can be done at the Earth's surface. The transport system for a tower consists of a small engine (used only for friction compensation) located at the Earth's surface. The tower is separated into sections and has special protection mechanisms in case of damage. Problems involving security, control, repair, and stability of the proposed towers are addressed in other publications. The author is prepared to discuss these and other problems with serious organizations desiring to research and develop these projects.

Bolonkin, Alexander

2003-01-01

394

AFCATT (Anti-Fouling Chemical Additive Test Tower)  

SciTech Connect

Polyvinylchloride (PVC) film-type cellular fill is the fill of choice in replacing cement asbestos 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, significantly reducing tower performance and the fill`s useful life. The Anti-Fouling Chemical Additives Test Tower (AFCATT) has been build 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. To determine the success of these different treatment programs, statistical analyses were performed on the collected data and the changes in the accumulation rates compared.

Philpot, E.F.; Newton, M.T.; Noble, R.T. [Southern Company Services, Birmingham, AL (United States)] [and others

1995-06-01

395

Greenhouse gas observations from Cabauw Tall Tower (1992-2010)  

NASA Astrophysics Data System (ADS)

Since 1992 semi-continuous in-situ observations of greenhouse gas concentrations have been performed at the tall tower of Cabauw (4.927° E, 51.971° N, -0.7 m a.s.l.). Through 1992 up to now, the measurement system has been gradually extended and improved in precision, starting with CO2 and CH4 concentrations from 200 m a.g.l. in 1992 to vertical gradients at 4 levels of the gases CO2, CH4, SF6, N2O, H2, CO and gradients at 2 levels for 222Rn. In this paper the measurement systems and measurement results are described for the main greenhouse gases and CO, for the whole period. The automatic measurement system now provides half-hourly concentration gradients with a precision better than or close to the WMO recommendations. The observations at Cabauw show a complex pattern caused by the influence of sources and sinks from a large area around the tower with significant contributions of sources and sinks at distances up to 500-700 km. The concentration footprint area of Cabauw is one the most intensive and complex source areas of greenhouse gases in the world. Despite this, annual mean trends for the most important greenhouse gases, compatible with the values derived using the global network, can be reproduced from the measured concentrations at Cabauw over the entire measurement period, with a measured increase in the period 2000-2009 for CO2 of 1.90 ± 0.1 ppm yr-1, for CH4 of 4.4 ± 0.6 ppb yr-1, for N2O of 0.86 ± 0.04 ppb yr-1, and for SF6 of 0.27 ± 0.01 ppt yr-1; for CO no significant trend could be detected. The influences of strong local sources and sinks are reflected in the amplitude of the mean seasonal cycles observed at Cabauw, that are larger than the mean Northern Hemisphere average; Cabauw mean seasonal amplitude for CO2 is 25-30 ppm (higher value for lower sampling levels). The observed CH4 seasonal amplitude is 50-110 ppb. All gases except N2O show highest concentrations in winter and lower concentrations in summer, N2O observations show two additional concentration maxima in early summer and in autumn. Seasonal cycles of the day-time mean concentrations show that surface concentrations or high elevation concentrations alone do not give a representative value for the boundary layer concentrations, especially in winter time, but that the vertical profile data along the mast can be used to construct a useful boundary layer mean value. The variability at Cabauw in the atmospheric concentrations of CO2 on time scales of minutes to hours is several ppm and is much larger than the precision of the measurements (0.1 ppm). The diurnal and synoptical variability of the concentrations at Cabauw carry information on the sources and sinks in the footprint area of the mast, that will be useful in combination with inverse atmospheric transport model to verify emission estimates and improve ecosystem models. For this purpose a network of tall tower stations like Cabauw forms a very useful addition to the existing global observing network for greenhouse gases.

Vermeulen, A. T.; Hensen, A.; Popa, M. E.; van den Bulk, W. C. M.; Jongejan, P. A. C.

2011-03-01

396

Greenhouse gas observations from Cabauw Tall Tower (1992-2010)  

NASA Astrophysics Data System (ADS)

Since 1992 semi-continuous in-situ observations of greenhouse gas concentrations have been performed at the tall tower of Cabauw (4.927° E, 51.971° N, -0.7 m a.s.l.). Through 1992 up to now, the measurement system has been gradually extended and improved in precision, starting with CO2 and CH4 concentrations from 200 m a.g.l. in 1992 to vertical gradients at 4 levels of the gases CO2, CH4, SF6, N2O, H2, CO and gradients at 2 levels for 222Rn. In this paper the measurement systems and measurement results are described for the main greenhouse gases and CO for the whole period. The automatic measurement system now provides half-hourly concentrations gradient with a precision better than or close to the WMO recommendations. The observations at Cabauw show a complex pattern caused by the influence of sources and sinks from a large area around the tower with significant contributions of sources and sinks at distances up to 500-700 km. The concentration footprint area of Cabauw is one the most intensive and complex source areas of greenhouse gases in the world. Despite this, annual mean trends for the most important greenhouse gases, compatible with the global values derived using the global network, can be reproduced from the measured concentrations at Cabauw over the entire measurement period, with a measured increase in the period 2000-2009 for CO2 of 1.90 ± 0.1 ppm yr-1, for CH4 of 4.4 ± 0.6 ppb yr-1, for N2O of 0.86 ± 0.04 ppb yr-1, and for SF6 of 0.27 ± 0.01 ppt yr-1; for CO no significant trend could be detected. The strong local sources and sinks reflect in the amplitude of mean seasonal cycles observed at Cabauw, that are larger than the mean Northern Hemisphere average; Cabauw mean seasonal amplitude for CO2 is 25-30 ppm (higher value for lower levels). CH4 seasonal amplitude observed is 50-110 ppb. All gases except N2O show highest concentrations in winter and lower concentrations in summer, N2O observations show two additional concentrations maxima in early summer and in autumn. Seasonal cycles of the day-time mean concentrations show that surface concentrations or high elevation concentrations alone do not give a representative value for the boundary layer concentrations, especially in winter time, but that the vertical profile data along the mast can be used to construct a useful boundary layer mean value. The variability at Cabauw in the atmospheric concentrations of CO2 on time scales of minutes to hours is several ppm and is much larger than the precision of the measurements (0.1 ppm). The diurnal and synoptical variability of the concentrations at Cabauw carry information on the sources and sinks in the footprint area of the mast, that is and will be used in combination with inverse atmospheric transport model to verify emission estimates and improve ecosystem models. For this purpose a network of tall tower stations like Cabauw is a very useful addition to the existing global observing network for greenhouse gases.

Vermeulen, A. T.; Hensen, A.; Popa, M. E.; van den Bulk, W. C. M.; Jongejan, P. A. C.

2010-09-01

397

Wind Generation on Winnebago Tribal Lands  

SciTech Connect

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 monitored wind data at the WinnaVegas Casino on the far eastern edge of the Winnebago reservation in Iowa. In late 2006, a 50-meter tower was installed, and subsequently monitored wind data at the WinnaVegas site from late 2006 through late 2008. Significant challenges with the NREL wind monitoring equipment limited the availability of valid data, but based on the available data, average wind speeds between 13.6 – 14.3 miles were indicated, reflecting a 2+/3- wind class. Based on the anticipated cost of energy produced by a WinnaVegas wind turbine, and the utility policies and rates in place at this time, a WinnaVegas wind project did not appear to make economic sense. However, if substantial grant funding were available for energy equipment at the casino site, and if either Woodbury REC backup rates were lower, or NIPCO was willing to pay more for wind power, a WinnaVegas wind project could be feasible. With funding remaining in the DOE-funded project budget,a number of other possible wind project locations on the Winnebago reservation were considered. in early 2009, a NPPD-owned met tower was installed at a site identified in the study pursuant to a verbal agreement with NPPD which provided for power from any ultimately developed project on the Western Winnebago site to be sold to NPPD. Results from the first seven months of wind monitoring at the Western Winnebago site were as expected at just over 7 meters per second at 50-meter tower height, reflecting Class 4 wind speeds, adequate for commercial development. If wind data collected in the remaining months of the twelve-month collection period is consistent with that collected in the first seven months, the Western Winnebago site may present an interesting opportunity for Winnebago. Given the distance to nearby substations, and high cost of interconnection at higher voltage transmission lines, Winnebago would likely need to be part of a larger project in order to reduce power costs to more attractive levels. Another alternative would be to pursue grant funding for a portion of development or equipment costs, which would also help reduce the cost of power produced. The NREL tower from the WinnaVegas site was taken down in late 2008, re-instrumented and installation attempted on the Thunderway site south of the Winnebago community. Based on projected wind speeds, current equipment costs, and the project’s proximity to substations for possible interconnection, a Thunderway community-scale wind project could also be feasible.

Multiple

2009-09-30

398

Wind Speed Estimation Based Sensorless Output Maximization Control for a Wind Turbine Driving a DFIG  

Microsoft Academic Search

This paper proposes a wind speed estimation based sensorless maximum wind power tracking control for variable-speed wind turbine generators (WTGs). A specific design of the proposed control algorithm for a wind turbine equipped with a doubly fed induction generator (DFIG) is presented. The aerodynamic characteristics of the wind turbine are approximated by a Gaussian radial basis function network based nonlinear

Wei Qiao; Wei Zhou; JosÉ M. Aller; Ronald G. Harley

2008-01-01

399

Power Electronics and Wind Power  

E-print Network

Renewable energy facilities will constitute a major contribution to electrical power in the future. The wind turbine will, together with biomass, form the major renewables parts up to year 2030 including erection of offshore wind farms. The wind is a non-storable energy source, whose electric energy needs priming into interchangeable energy to be competitive for large-scale power generation. An essential task is then to make wind power as commercially valuable and fungible as electric power produced by traditional, dispatched plants such as fossil fuel power plants, hydroelectric plants, nuclear plants and the like. Power electronics is a fundamental candidate when priming wind power. Another candidate is automation starting in the towers and ending in load management. Power electronics and automation shall be cost-effective and reliable. Power electronic hardware shall be common but in moderation because losses and investments must be paid back: by better trading on the power exchange, by availability, by reduced mechanical and/or civil engineering as well as by efficiency and reliability. An overview of wind power from different perspectives: collection & transmission (C&T), energy storage, R&D e.g. in EU and US, existing technology, wind’s future(s) business, etc. is comprised. EPE should be challenged to exploit wind power opportunities.

Gertmar Lars; Lars Gertmar; Systems Power Transmission

400

Wind turbine acoustic standards  

NASA Technical Reports Server (NTRS)

A program is being conducted to develop noise standards for wind turbines which minimize annoyance and which can be used to design specifications. The approach consists of presenting wind turbine noise stimuli to test subjects in a laboratory listening chamber. The responses of the subjects are recorded for a range of stimuli which encompass the designs, operating conditions, and ambient noise levels of current and future installations. Results to date have established the threshold of detectability for a range of impulsive stimuli of the type associated with blade/tower wake interactions. The status of the ongoing psychoacoustic tests, the subjective data, and the approach to the development of acoustic criteria/standards are described.

Stephens, D. G.; Shepherd, K. P.; Grosveld, F.

1981-01-01

401

Development of the LSST raft tower modules  

NASA Astrophysics Data System (ADS)

The science focal plane of the Large Synoptic Survey Telescope is made up of 21 modules designated "raft towers". Each raft tower module (RTM) is an autonomous, fully-testable and serviceable 144 Mpixel imager consisting of nine highly-segmented CCDs with complete readout electronics chain. To minimize noise and obscuration the RTM is housed in a compact enclosure fully contained within the camera cryostat. The RTM is required to meet strict performance goals for image plane flatness, readout speed, noise, and power dissipation. Key components include the 4K × 4K fully-depleted CCDs with 16 outputs each, ceramic CCD support structure, and ASIC electronics for video processing and clock/bias generation. In addition to CCD signal handling, the RTM electronics also includes monitoring for temperature, voltage, and current, makeup heater control, ASIC configuration and readback, powerdown modes, and specialized diagnostic outputs. Digitized data are transmitted out of the camera cryostat over a single 3Gb/s serial link.

O'Connor, P.; Kotov, I.; Takacs, P. Z.; Frank, J. S.; Plate, S.; Van Berg, R.; Newcomer, M.; Antilogus, P.; Lebbolo, Hervé; Tocut, V.; Juramy, C.; Doherty, P.; Felt, N.

2012-07-01

402

A Study of Lightning Current Distribution at a Wind Turbine Foot  

NASA Astrophysics Data System (ADS)

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

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

403

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

SciTech Connect

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

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

2012-01-01

404

A Neural Networks Based Method to Estimate Higher Resolution Aerosol Optical Thickness Using Historical Data Sets of SEVIRI Dust Indices, Soil Moisture and Wind Speed  

NASA Astrophysics Data System (ADS)

Dust emission has a large temporal and spatial variation making it extremely challenging to model. This challenge is mainly due to the number of uncertainties in estimating the amount of dust emission and deposition. Dust emission and deposition are associated with several factors such as surface roughness, soil particle properties, wind speed and direction, precipitation, humidity, and threshold wind friction velocity. Aerosol optical thickness (AOT) is a widely used quantitative indicator of dust in the atmosphere but its use is limited either because the availability of AOT data measured at ground is very limited or satellite-derived AOT suffers from the coarser temporal and spatial resolution. SEVIRI data have been widely used for qualitative detection of dust because of the availability of thermal channels and their high temporal resolution. However, no SEVIRI-derived AOT products are available yet. Freely available AOT product over land as well as ocean derived using MODIS data has a limited temporal (daily) and spatial resolution (1°×1°). The combination of satellite and land surface data will be useful in forecasting dust storms. This is mainly because some input parameters like AOT, soil moisture and land cover properties can be more effectively obtained using satellite data. However, other parameters like soil type, wind speed and soil particle size distribution requires more accurate ground measurement. Neural networks can be effectively used to study the non-linear relationship between complex input parameters and specified output(s). In this work higher resolution SEVIRI dust indices have been used as input parameters to derive higher resolution AOT data as output with MODIS AOT as target. Apart from SEVIRI dust indices, satellite derived soil moisture data from AMSR-E and wind speed data measured at ground station have also been used as additional inputs. The selection of these additional inputs was mainly motivated by their direct and indirect relationship with dust emission. In fact, AOT is inversely proportional to the soil moisture and directly proportional to the wind speed in general when the major fraction of the aerosols consists of wind eroded dust. MODIS AOT data used in this study include all the available cloud free days of the year 2009 and the input parameters were retrieved at a closest time (13:45) of MODIS/Aqua overpass over a small area (25×25 km) centered at (23.38° N, 53.88° E) in the UAE. A total of 191 points were available for analysis of which two-thirds were used to train the neural network and the rest one-thirds were used for validation. A strong correlation was observed both in training and validation phase which was used to simulate higher resolution AOT with the available SEVIRI dust indices, soil moisture and wind speed data as inputs.

Parajuli, S. P.; Ghedira, H.; Gherboudj, I.

2011-12-01

405

Hybrid Photovoltaic-Wind system as power solution for network operators in the D.R.Congo  

Microsoft Academic Search

Escalating diesel prices and to a lesser extent a desire to reduce global warming gasses, have caused most mobile operators to seriously start looking at alternatives to standard diesel electric set on remote sites. This paper investigates the possibility of using a hybrid Photovoltaic-Wind power system to supply Base Transceiver Station load in the Democratic Republic of Congo. The Hybrid

K. Kusakana; H. J. Vermaak

2011-01-01

406

Comparison of the response of doubly fed and fixed-speed induction generator wind turbines to changes in network frequency  

Microsoft Academic Search

Synchronous and fixed-speed induction generators release the kinetic energy of their rotating mass when the power system frequency is reduced. In the case of doubly fed induction generator (DFIG)-based wind turbines, their control system operates to apply a restraining torque to the rotor according to a predetermined curve with respect to the rotor speed. This control system is not based

J. Ekanayake; N. Jenkins

2004-01-01

407

Logarithmic Wind Profile: A Stability Wind Shear Term  

E-print Network

A stability wind shear term of logarithmic wind profile based on the terms of turbulent kinetic energy equation is proposed. The fraction influenced by thermal stratification is considered in the shear production term. This thermally affected shear is compared with buoyant term resulting in a stability wind shear term. It is also considered Reynolds stress as a sum of two components associated with wind shear from mechanical and thermal stratification process. The stability wind shear is responsible to Reynolds stress of thermal stratification term, and also to Reynolds stress of mechanical term at no neutral condition. The wind profile and its derivative are validated with data from Pedra do Sal experiment in a flat terrain and 300m from shoreline located in northeast coast of Brazil. It is close to the Equator line, so the meteorological condition are strongly influenced by trade winds and sea breeze. The site has one 100m tower with five instrumented levels, one 3D sonic anemometer, and a medium-range wind...

Sakagami, Yoshiaki; Haas, Reinaldo; Passos, Julio C; Taves, Frederico F

2014-01-01

408

View of lifting girder and tower support superstructure on Tensaw ...  

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

View of lifting girder and tower support superstructure on Tensaw River Bridge, looking north west. Showing rope connectors and welding cut from tower removal. - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

409

AR-HUD system for tower crane on construction field  

Microsoft Academic Search

Recently, safety problem of construction field is becoming more serious as construction environment is getting more complex. For example, construction field can cause accidents due to many heavy materials and equipments on the field. Tower crane is the one of the heavy equipments for moving heavy materials on construction field. Tower crane driver should be able to identify all materials

HanNa Lee; HyungSeok Kim; Jee-In Kim; Hanku Lee; Mu Wook Pyeon

2011-01-01

410

Design of a self-balancing tower crane  

Microsoft Academic Search

This paper presents a new concept of a tower crane, which greatly reduces the ballast and eliminates the anchoring, as will be “self-balancing” which implies removing the anchoring replaced by a sliding counterweight trolley. This paper presents the design of the mechanics as well as the final assembled self-balancing tower crane. Its dynamical model has been obtained and controlled by

Jose de Jesus Rubio; J. JAIMES-PONCE

2007-01-01

411

8. INTERIOR VIEW OF ASSEMBLY ROOM (REAR FACADE), UNTANKING TOWER, ...  

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

8. INTERIOR VIEW OF ASSEMBLY ROOM (REAR FACADE), UNTANKING TOWER, SHOWING PREVIOUS MODIFICATIONS (INSTALLATION OF METAL ROLL-UP DOOR, LEFT FOREGROUND). 125-TON LIFTING CRANE (TOP FOREGROUND), AND ORIGINAL FLOOR-TO-CEILING MULTI-PANE, METAL-CASED WINDOWS - Bonneville Power Administration Chehalis Substation, Untanking Tower, State Route 603, West of Interstate 5, Napavine, Lewis County, WA

412

Automation of existing tower cranes: economic and technological feasibility  

Microsoft Academic Search

Tower cranes enjoy a long useful working life. Therefore, a vast population of cranes are still in use today that do not feature the advanced automation and sensor technologies such as those with which some of the new models are equipped. This paper examines the technological and economic feasibility of retrofitting existing tower cranes with semi-automatic devices for motion control.

Yehiel Rosenfeld; Aviad Shapira

1998-01-01

413

Forced Draft Cooling Tower Performance with Diesel Power Stations  

Microsoft Academic Search

A prototype cooling tower was used to explore the potential of using cooling towers compared with radiator cooling systems with 3 MW diesel engines. The working parameters were the water mass flow rate, water inlet temperature, air mass flow rate, and humidity ratio. The water mass flow rate was relatively the most effective. Three methods of calculation were used to

YOUSEF S. H. NAJJAR

1988-01-01

414

A simple iterative algorithm for the towers of Hanoi problem  

Microsoft Academic Search

The towers of Hanoi game is well known. The basic version, a favorite example for many authors, is often used in introductory textbooks on computer programming to demonstrate the elegance of writing recursive code. Here, a simple iterative optimal algorithm for the towers of Hanoi problem is presented

Fouad B. Chedid; Toshiya Mogi

1996-01-01

415

Sequoias, Mavericks, Open Doors...Composing Joan Tower  

ERIC Educational Resources Information Center

This essay interview with Joan Tower is a meditation on the importance of composing, understood as a process larger than the making of new sound combinations or musical scores, suggesting that the compositional act is self-educative and self-forming. Tower's musical life, one of teaching and learning, one of composing and self-composing, is an…

Allsup, Randall Everett

2011-01-01

416

Isolation of Legionella pneumophila from Cooling Tower Water by Filtration  

PubMed Central

Methods are described for detection of Legionella pneumophila in cooling tower water or other water sources by direct fluorescent-antibody staining. A procedure for isolation of Legionella bacteria from water samples by guinea pig inoculation is described. Two different serogroups of L. pneumophila were isolated repeatedly from one of the cooling towers. PMID:7020594

Orrison, Leta H.; Cherry, William B.; Milan, David

1981-01-01

417

2. Light tower and oil house, view west, southeast and ...  

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

2. Light tower and oil house, view west, southeast and northeast sides of tower and south side of oil house - Goat Island Light Station, Goat Island, next to entrance to Cape Porpoise Harbor, just south of Trott Island, Cape Porpoise, York County, ME

418

2. Keeper's house, light tower and oil house, view north, ...  

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

2. Keeper's house, light tower and oil house, view north, south and east sides of keeper's house, south side of tower and oil house - Owl's Head Light Station, Off State Highway 73 just east of Rockland on Owl's Head Bay, Owls Head, Knox County, ME

419

GATEHOUSE AND TOWER, KACHESS RIVER CHANNEL (1910), LOOKING EAST (Feature ...  

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

GATEHOUSE AND TOWER, KACHESS RIVER CHANNEL (1910), LOOKING EAST (Feature WA-79-G, cutoff channel and crib at center left, bridge footing visible behind and right of tower) - Kachess Dam, Gatehouse, Kachess River, 1.5 miles north of Interstate 90, Easton, Kittitas County, WA

420

15. Como gatehouse (outlet tower) and access bridge, looking west ...  

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

15. Como gatehouse (outlet tower) and access bridge, looking west from dam crest (Trash rack visible in reservoir pool behind and right of tower) - Bitter Root Irrigation Project, Como Dam, West of U.S. Highway 93, Darby, Ravalli County, MT

421

16. Detail, northeast facade, operator's bow window and tower; note ...  

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

16. Detail, northeast facade, operator's bow window and tower; note condition of slates on tower skirt roof, missing section of gutter at left side of skirt roof, missing window panes; note also knee braces carried on masonry ancons; view to southwest, 90mm lens. - Southern Pacific Depot, 559 El Camino Real, San Carlos, San Mateo County, CA

422

Water cooling tower and water level control system therefor  

Microsoft Academic Search

This patent describes an improved water cooling tower system including a water cooling tower structure having a top portion, a bottom portion, an intermediate portion therebetween, a water-collecting basin operatively disposed in the bottom portion of the structure, a heat exchange means operatively disposed in the intermediate portion of the structure, means for recirculating the water from the water-collecting basin

Kinkead

1989-01-01

423

Aircraft Impact Analyses of the World Trade Center Towers  

Microsoft Academic Search

Although some official statements have been released by the Federal Emergency Management Agency (FEMA) and the National Institute of Standards and Technology (NIST), the 9\\/11 tragedy of the New York World Trade Center (WTC) towers still remains as an unresolved mystery since the progressive collapse sequence of the towers was unnaturally rapid. We sought the true cause of the collapse

D. Isobe; Z. Sasaki

424

OVERVIEW OF AERIAL TRAM SUPPORT TOWERS NINE, TEN, AND DEEP ...  

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

OVERVIEW OF AERIAL TRAM SUPPORT TOWERS NINE, TEN, AND DEEP RAVINE,LOOKING SOUTH FROM BREAK OVER TOWER LOCATION. A SINGLE ORE BUCKET HANGS FROM THE CABLE AT CENTER. DEATH VALLEY'S FLOOR IS IN THE DISTANCE (TOP). - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

425

HARMON HOUSE ELEVATION VIEW OF WEST FAÇADE WITH OCTAGONAL TOWER. ...  

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

HARMON HOUSE ELEVATION VIEW OF WEST FAÇADE WITH OCTAGONAL TOWER. (The house was reroofed in the fall of 2006, after an attic fire in March of that same year. Image also shows Flora A. Engle?s octagon tower addition, the front entry to the house, and brooding chickens.) - Engle Farm, House, 89 South Ebey Road, Coupeville, Island County, WA

426

Update on the Purdue University 2-second Drop Tower  

Microsoft Academic Search

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

Steven Collicott

2010-01-01

427

2. Fog signal house and light tower, view west southwest, ...  

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

2. Fog signal house and light tower, view west southwest, southeast and northeast sides of signal house, east and north sides of tower - Libby Island Light Station, At southern tip of Libby Island at entrance to Machias Bay, Machiasport, Washington County, ME

428

7. Keeper's house, fog signal house and light tower, view ...  

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

7. Keeper's house, fog signal house and light tower, view north northeast, west and south sides of keeper's house and tower, southwest and southeast sides of fog signal house - West Quoddy Head Light Station, At eastern tip of West Quaddy Head, Lubec, Washington County, ME

429

1. Light tower and fog signal house, view south southeast, ...  

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

1. Light tower and fog signal house, view south southeast, east and north sides of tower, northeast and northwest sides of signal house - Libby Island Light Station, At southern tip of Libby Island at entrance to Machias Bay, Machiasport, Washington County, ME

430

PS10 Solar Power Tower Xi Jing, Fang  

E-print Network

area equivalent of 17 American Football Tower Solar receiver 4 vertical panels 18ft*39ft Steam turbinePS10 Solar Power Tower Xi Jing, Fang #12;Overview Magnitudes , Cost & TechnologiesMagnitudes , Cost Government . #12;Further ExplanationFurther Explanation Plataforma Solar de Sanlúcar la Mayor,PSSM Megawatts

Prevedouros, Panos D.

431

Principles of calculation of oxidation towers in asphalt production  

Microsoft Academic Search

The oxidation process in a tower takes place in a sparged layer. The properties of the liquid in this layer are identical to that throughout the height of the layer [I], in spite of the constant input of feedstock and withdrawal of product at different levels. Thus, with respect to the liquid phase, the tower is essentially an ideal-mixing vessel.

I. B. Grudnikov; B. Grudnikov

1984-01-01

432

Investigations of the Tornado Wind-Energy System. Final report, September 1978-April 1980  

SciTech Connect

Tornado-type Wind Energy Systems (TWES) use the core of a vortex in a hollow tower to provide a low pressure exhaust reservoir for a wind turbine. Wind tunnel data are presented, and previous and planned test programs are described, including the evolution of tower design from the spiral-cross-sectional design through the passive omnidirectional design to the fixed-vane omnidirectional design. A larger model with a 15-ft height tower and a 30-in. diameter turbine is described, including details on design, configuration, and instrumentation, plus details on the test-rig for testing the 30-in. turbine under a staight-flow environment. Results on turbine efficiency, tip-speed-ratio, and turbine disk loading coefficient are presented and discussed. A new cost analysis is presented that makes cost estimates for large TWES systems using the measured performance of small models without scaling laws, plus the tower cost estimates deduced from the simple structural anlaysis. (LEW)

Yen, J.T.

1980-05-01

433

Using a Network of Boundary Layer Profilers to Characterize the Atmosphere at a Major Spaceport  

NASA Technical Reports Server (NTRS)

Space launch, landing, and ground operations at the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida are highly sensitive to mesoscale weather conditions throughout the year. Due to the complex land-water interfaces and the important role of mesoscale circulations, a high-resolution network of five 915-MHz Doppler Radar Wind Profilers (DRWP) and 44 wind towers was installed over the KSC/CCAFS area. By using quality-controlled 915-MHz DRAT data along with the near-surface tower observations, the Applied Meteorology Unit and KSC Weather Office have studied the development and evolution of various mesoscale phenomena across KSC/CCAFS such as sea and land breezes, low-level jets, and frontal passages. This paper will present some examples of mesoscale phenomena that can impact space operations at KSC/CCAFS, focusing on the utility of the 915-MHz DRWP network in identifying important characteristics of sea/land breezes and low-level jets.

Case, Jonathan L.; Lambert, Winifred; Merceret, Francis; Ward, Jennifer

2006-01-01

434

Conversion Tower for Dispatchable Solar Power: High-Efficiency Solar-Electric Conversion Power Tower  

SciTech Connect

HEATS Project: Abengoa Solar is developing a high-efficiency solar-electric conversion tower to enable low-cost, fully dispatchable solar energy generation. Abengoa’s conversion tower utilizes new system architecture and a two-phase thermal energy storage media with an efficient supercritical carbon dioxide (CO2) power cycle. The company is using a high-temperature heat-transfer fluid with a phase change in between its hot and cold operating temperature. The fluid serves as a heat storage material and is cheaper and more efficient than conventional heat-storage materials, like molten salt. It also allows the use of a high heat flux solar receiver, advanced high thermal energy density storage, and more efficient power cycles.

None

2012-01-11

435

Tower reactors for bioconversion of lignocellulosic material  

DOEpatents

An apparatus is disclosed for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material. The apparatus consists of a tower bioreactor which has mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Nguyen, Q.A.

1998-03-31

436

Tower reactors for bioconversion of lignocellulosic material  

DOEpatents

An apparatus is described for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Nguyen, Q.A.

1999-03-30

437

Accurate aircraft wind measurements using the global positioning system (GPS)  

SciTech Connect

High accuracy measurements of the spatial distribution of wind speed are required in the study of turbulent exchange between the atmosphere and the earth. The use of a differential global positioning system (GPS) to determine the sensor velocity vector component of wind speed is discussed in this paper. The results of noise and rocking testing are summarized, and fluxes obtained from the GPS-based methods are compared to those measured from systems on towers and airplanes. The GPS-based methods provided usable measurements that compared well with tower and aircraft data at a significantly lower cost. 21 refs., 1 fig., 2 tabs.

Dobosy, R.J.; Crawford, T.L., McMillen, R.T., Dumas, E.J. [Atmospheric Turbulence and Diffusion Div., Oak Ridge, TN (United States)

1996-11-01

438

Large CO2 reductions via offshore wind power matched to inherent storage in energy end-uses  

E-print Network

of the planetary boundary layer (PBL) over water and a wind- electric technology analysis linking turbine and tower, 2002]. Disadvantages of offshore wind include: higher installation and maintenance costs in comparisonLarge CO2 reductions via offshore wind power matched to inherent storage in energy end-uses Willett

Jacobson, Mark

439

Field verification program for small wind turbines, Block Island, Rhode Island. Quarterly report for the period October to December 1999  

Microsoft Academic Search

The proposal is to install and monitor five 10-kW residential wind turbines on 25-meter towers on Block Island, which has excellent wind resources and high electricity costs. The harsh environment will provide an opportunity for accelerated reliability testing of an enhanced wind turbine and other equipment.

Henry G. duPont

2000-01-01

440

Thermal, pressure and wind fields at ground level in the area of the Italian base at Terra Nova Bay, Victoria Land, Antarctica, as observed by a network of automatic weather stations  

Microsoft Academic Search

Ground temperature, pressure and wind speed monthly averages in the area of the Italian Station at Terra Nova Bay, Antarctica, were analyzed for the period 1987—1991 by means of a network of nine AWS (auto- matic weather stations). Spatial configurations of temper- ature show a well-defined, relatively warm island in the area of Terra Nova Bay, between Drygalsky and Campbell

E. Cogliani; G. Abbate; S. Racalbuto

1996-01-01

441

Thermal, pressure and wind fields at ground level in the area of the Italian base at Terra Nova Bay, Victoria Land, Antarctica, as observed by a network of automatic weather stations  

Microsoft Academic Search

Ground temperature, pressure and wind speed monthly averages in the area of the Italian Station at Terra Nova Bay, Antarctica, were analyzed for the period 1987–1991 by means of a network of nine AWS (automatic weather stations). Spatial configurations of temperature show a well-defined, relatively warm island in the area of Terra Nova Bay, between Drygalsky and Campbell ice tongues,

E. Cogliani; G. Abbate; S. Racalbuto

1997-01-01

442

New Concepts in Wind Power Forecasting Models  

E-print Network

New Concepts in Wind Power Forecasting Models Vladimiro Miranda, Ricardo Bessa, João Gama, Guenter to the training of mappers such as neural networks to perform wind power prediction as a function of wind for more accurate short term wind power forecasting models has led to solid and impressive development

Kemner, Ken

443

Polarization dynamics in optical ground wire network.  

PubMed

We report the polarization dynamics in an optical ground wire (OPGW) network for a summer period and a fall period for what is believed to be the first time. To better observe the surrounding magnetic fields contribution to modulating the state of polarization (SOP) we installed a Faraday rotating mirror to correct reciprocal birefringence from quasi-static changes. We also monitored the OPGW while no electrical current was present in the towers' electrical conductors. The spectral analysis, the arc length mapped out over a given time interval on a Poincaré sphere, histograms of the arc length, and the SOP autocorrelation function are calculated to analyze the SOP changes. Ambient temperature changes, wind, Sun-induced temperature gradients, and electrical current all have a significant impact on the SOP drift in an OPGW network. Wind-generated cable oscillations and Sun-induced temperature gradients are shown to be the dominant slow SOP modulations, while Aeolian vibrations and electrical current are shown to be the dominant fast SOP modulations. The spectral analysis revealed that the electrical current gives the fastest SOP modulation to be 300 Hz for the sampling frequency of 1 KHz. This has set the upper speed limit for real-time polarization mode dispersion compensation devices. PMID:19381169

Leeson, Jesse; Bao, Xiaoyi; Côté, Alain

2009-04-20

444

Three-dimensional wind measurements in the optically clear planetary boundary layer with dual-Doppler radar  

Microsoft Academic Search

The radar measurements obtained are compared with in situ measurements on aircraft, on the instrumented tower, and with other surface wind data. Preliminary results indicate that these data resolve wavelengths as small as 600 m and that the measurements are repeatable at each grid point to within 0.3 m\\/s. The radar-derived wind fluctuations agreed with anemometer data on the tower

R. A. Kropfli; P. H. Hildebrand

1980-01-01

445

Power Tower Technology Roadmap and cost reduction plan.  

SciTech Connect

Concentrating solar power (CSP) technologies continue to mature and are being deployed worldwide. Power towers will likely play an essential role in the future development of CSP due to their potential to provide dispatchable solar electricity at a low cost. This Power Tower Technology Roadmap has been developed by the U.S. Department of Energy (DOE) to describe the current technology, the improvement opportunities that exist for the technology, and the specific activities needed to reach the DOE programmatic target of providing competitively-priced electricity in the intermediate and baseload power markets by 2020. As a first step in developing this roadmap, a Power Tower Roadmap Workshop that included the tower industry, national laboratories, and DOE was held in March 2010. A number of technology improvement opportunities (TIOs) were identified at this workshop and separated into four categories associated with power tower subsystems: solar collector field, solar receiver, thermal energy storage, and power block/balance of plant. In this roadmap, the TIOs associated with power tower technologies are identified along with their respective impacts on the cost of delivered electricity. In addition, development timelines and estimated budgets to achieve cost reduction goals are presented. The roadmap does not present a single path for achieving these goals, but rather provides a process for evaluating a set of options from which DOE and industry can select to accelerate power tower R&D, cost reductions, and commercial deployment.

Mancini, Thomas R.; Gary, Jesse A. (U.S. Department of Energy); Kolb, Gregory J.; Ho, Clifford Kuofei

2011-04-01

446

Numerical study of the performance of tornado-type wind energy systems  

SciTech Connect

The tornado-type wind energy system was proposed to utilize the pressure drop created by an intens vortex in a tower. The tower serves as a low pressure exhaust for the turbine. The author carried out a numerical solution of the tower flow, using the two-equation (kappa-epsilon) turbulence model, for the small size system tested by Yen, with a 0.127-m- (5-in.-) diam tower standing in a uniform wind flow. A comparison of the results with the measured pressure values verified the model. In the present work the same numerical model is used for a system with a tower that is completely embedded in an atmospheric boundary layer. The results show, for a tower in a boundary layer of the one-seventh power-law profile, about a 28% reduction of the values of power coefficient from those for a tower in a uniform stream. Calculations for the performance of a system with different tower heights and the same tower and turbine diameters show a sharp decrease of power for H/D less than or equal to 0.5. Analysis of the tangential velocity shows that the vortex should be maintained up to heights /ZETA//D less than or equal to 0.9 to avoid the decrease in power extraction. Numerical predictions are made for systems with tower diameters between 0.5 and 8 m (1.64 and 26.24 ft) using the same system geometry and approach flow conditions. The results show that the scale effect is negligible for systems of 4-m tower diameter or larger.

Ayad, S.S.

1983-03-01

447

On network design for the detection of urban greenhouse gas emissions: Results from the Indianapolis Flux Experiment (INFLUX) (Invited)  

NASA Astrophysics Data System (ADS)

The Indianapolis Flux Experiment (INFLUX) was designed to develop and evaluate methods for the measurement and modeling of greenhouse gas fluxes from urban environments. Determination of greenhouse gas fluxes and uncertainty bounds is essential for the evaluation of the effectiveness of mitigation strategies. The current INFLUX observation network includes twelve in-situ tower-based, continuous measurements of CO2, CO, and CH4, flask sampling of 14CO2 and other trace gases, and periodic aircraft sampling of greenhouse gases and meteorological conditions. A total carbon column observing network (TCCON) column remote sensing station was deployed Aug - Dec 2012. The network will soon be enhanced to include an array of eddy covariance and radiative flux measurements, and a scanning Doppler lidar was installed in April 2013; both are used to quantify key boundary layer meteorological properties and evaluate model performance. The data from the towers, TCCON, and aircraft measurements are being used in an inverse-modeling approach to yield estimates of the urban area flux at 1 km2 resolution. Additionally, very high space/time resolution estimates of fossil fuel carbon emissions (Hestia project) offer state-of-the-art "bottom up" emissions estimates for the city and its surroundings. Here we present an overview of the progress from INFLUX, with a focus on tower-based results. With the unprecedented density of urban tower-based greenhouse gas measurements, we will quantify horizontal and vertical spatial patterns in atmospheric mole fractions of CO2, CO, and CH4 in Indianapolis. The consistency of the observed horizontal gradients with that expected based on differences in land-cover contributions according to footprint analysis will be evaluated. To address the optimal spatial density of tower-based measurements within the city, we will evaluate the spatial coverage of the model footprints. Using observations at several heights on the towers, we will investigate the performance of the forward model, thus addressing the question of the required height for these types of measurements. The ability to correctly model transport and mixing in the atmospheric boundary layer, responsible for carrying greenhouse gases from their source to the point of measurement, is essential. Thus we investigate differences between the modeled and observed sensible heat flux, latent heat flux, air temperature, and wind speed. Finally, we will present initial results of the emissions estimates from the inversion model.

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

2013-12-01

448

Visual Features Involving Motion Seen from Airport Control Towers  

NASA Technical Reports Server (NTRS)

Visual motion cues are used by tower controllers to support both visual and anticipated separation. Some of these cues are tabulated as part of the overall set of visual features used in towers to separate aircraft. An initial analyses of one motion cue, landing deceleration, is provided as a basis for evaluating how controllers detect and use it for spacing aircraft on or near the surface. Understanding cues like it will help determine if they can be safely used in a remote/virtual tower in which their presentation may be visually degraded.

Ellis, Stephen R.; Liston, Dorion

2010-01-01

449

Optimal sequencing of a cooling tower with multiple cells  

E-print Network

Modeling The mass and heat transfer process in a cooling tower is very complicated. The first practical theory of cooling tower operation was developed by Merkel [10] where there was counter-flow contact of water and air, and it has been the basis... of most cooling tower analyses. In Merkel?s analysis, the water loss due to evaporation was neglected and a Lewis number of unity was assumed. Merkel assumed that the bulk water in contact with a stream of air was surrounded by a film of saturated air...

Zhang, Z.; Liu, J.

2012-01-01

450

PBF Cooling Tower detail. Camera facing southwest into north side ...  

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

PBF Cooling Tower detail. Camera facing southwest into north side of Tower. Five horizontal layers of splash bars constitute fill decks, which will break up falling water into droplets, promoting evaporative cooling. Louvered faces, through which air enters tower, are on east and west sides. Louvers have been installed. Support framework for one of two venturi-shaped fan stacks (or "vents") is in center top. Orifices in hot basins (not in view) will distribute water over fill. Photographer: Kirsh. Date: May 15, 1969. INEEL negative no. 69-3032 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

451

Use of nanofiltration to reduce cooling tower water usage.  

SciTech Connect

Nanofiltration (NF) can effectively treat cooling-tower water to reduce water consumption and maximize water usage efficiency of thermoelectric power plants. A pilot is being run to verify theoretical calculations. A side stream of water from a 900 gpm cooling tower is being treated by NF with the permeate returning to the cooling tower and the concentrate being discharged. The membrane efficiency is as high as over 50%. Salt rejection ranges from 77-97% with higher rejection for divalent ions. The pilot has demonstrated a reduction of makeup water of almost 20% and a reduction of discharge of over 50%.

Sanchez, Andres L.; Everett, Randy L.; Jensen, Richard Pearson; Cappelle, Malynda A.; Altman, Susan Jeanne

2010-09-01

452

Building Designed Granular Towers One Drop at a Time  

NASA Astrophysics Data System (ADS)

A dense granular suspension dripping on an imbibing surface is observed to give rise to slender mechanically stable structures that we call granular towers. Successive drops of grain-liquid mixtures are shown to solidify rapidly upon contact with a liquid absorbing substrate. A balance of excess liquid flux and drainage rate is found to capture the typical growth and height of the towers. The tower width is captured by the Weber number, which gives the relative importance of inertia and capillary forces. Various symmetric, smooth, corrugated, zigzag, and chiral structures are observed by varying the impact velocity and the flux rate from droplet to jetting regime.

Chopin, Julien; Kudrolli, Arshad

2011-11-01

453

Linking Nocturnal Eddy Fluxes to Land Use-Land Cover in a Heterogeneous Landscape Surrounding the Urban-suburban Tower near Baltimore, Maryland  

NASA Astrophysics Data System (ADS)

Anthropogenic activities in urban ecosystems represent the key driving force for local and regional climate change scenarios, producing the various pollutants that cause environmental change at the global scale: elevated carbon dioxide (CO2), increased ozone and nitrogen deposition, and elevated temperatures. Measurements of eddy fluxes in an urban-suburban landscape pose technical difficulties as sinks and sources of CO2 surrounding the tower are non-uniform. In a recent study, we stratified half-hourly values of eddy fluxes, i.e., carbon dioxide (Fco2), latent energy (LE), and sensible heat (H), according to wind sectors. Additionally, remotely sensed (spatial) data were stratified according to wind sectors around the Cub Hill tower near Baltimore, Maryland. We found that diurnal eddy fluxes were empirically dependent on remotely sensed metrics within the two-kilometer radius surrounding the tower. We hypothesized that nocturnal eddy fluxes, as stratified into wind sectors, will be similarly dependent on the land use-land cover (LULC). In the present study, we pooled the nocturnal half-hourly eddy fluxes during a 6-year period (2004-09) into a single data set, and stratified the data according to 24 wind sectors representing the wind direction during each half-hourly eddy flux measurement. We ask the following questions: 1) Are the nocturnal eddy fluxes inter-dependent with each other? 2) Do the average nocturnal eddy fluxes on a daily basis differ between wind sectors? 3) Which micrometeorological variables determine the differences in eddy fluxes between wind sectors? 4) Do differences in nocturnal eddy fluxes among wind sectors depend upon LULC? 5) Are the relationships between nocturnal eddy fluxes and LULC consistent during Winter, Spring, Summer, and Fall? and 6) How do these nocturnal urban-suburban eddy fluxes compare with the nocturnal eddy fluxes in a nearby mixed deciduous rural forest? Results from the data analyses will be presented and discussed.

Saliendra, N. Z.; Hom, J. L.; Pouyat, R.; Nowak, D.; Heisler, G. M.; Patterson, M.; Yesilonis, I.

2010-12-01

454

Gradual disintegration of the floral symmetry gene network is implicated in the evolution of a wind-pollination syndrome.  

PubMed

Angiosperms exhibit staggering diversity in floral form, and evolution of floral morphology is often correlated with changes in pollination syndrome. The showy, bilaterally symmetrical flowers of the model species Antirrhinum majus (Plantaginaceae) are highly specialized for bee pollination. In A. majus, Cycloidea (CYC), Dichotoma (DICH), Radialis (RAD), and Divaricata (DIV) specify the development of floral bilateral symmetry. However, it is unclear to what extent evolution of these genes has resulted in flower morphological divergence among closely related members of Plantaginaceae differing in pollination syndrome. We compared floral symmetry genes from insect-pollinated Digitalis purpurea, which has bilaterally symmetrical flowers, with those from closely related Aragoa abietina and wind-pollinated Plantago major, both of which have radially symmetrical flowers. We demonstrate that Plantago, but not Aragoa, species have lost a dorsally expressed CYC-like gene and downstream targets RAD and DIV. Furthermore, the single P. major CYC-like gene is expressed across all regions of the flower, similar to expression of its ortholog in closely related Veronica serpyllifolia. We propose that changes in the expression of duplicated CYC-like genes led to the evolution of radial flower symmetry in Aragoa/Plantago, and that further disintegration of the symmetry gene pathway resulted in the wind-pollination syndrome of Plantago. This model underscores the potential importance of gene loss in the evolution of ecologically important traits. PMID:21282634

Preston, Jill C; Martinez, Ciera C; Hileman, Lena C

2011-02-01

455

Gradual disintegration of the floral symmetry gene network is implicated in the evolution of a wind-pollination syndrome  

PubMed Central

Angiosperms exhibit staggering diversity in floral form, and evolution of floral morphology is often correlated with changes in pollination syndrome. The showy, bilaterally symmetrical flowers of the model species Antirrhinum majus (Plantaginaceae) are highly specialized for bee pollination. In A. majus, CYCLOIDEA (CYC), DICHOTOMA (DICH), RADIALIS (RAD), and DIVARICATA (DIV) specify the development of floral bilateral symmetry. However, it is unclear to what extent evolution of these genes has resulted in flower morphological divergence among closely related members of Plantaginaceae differing in pollination syndrome. We compared floral symmetry genes from insect-pollinated Digitalis purpurea, which has bilaterally symmetrical flowers, with those from closely related Aragoa abietina and wind-pollinated Plantago major, both of which have radially symmetrical flowers. We demonstrate that Plantago, but not Aragoa, species have lost a dorsally expressed CYC-like gene and downstream targets RAD and DIV. Furthermore, the single P. major CYC-like gene is expressed across all regions of the flower, similar to expression of its ortholog in closely related Veronica serpyllifolia. We propose that changes in the expression of duplicated CYC-like genes led to the evolution of radial flower symmetry in Aragoa/Plantago, and that further disintegration of the symmetry gene pathway resulted in the wind-pollination syndrome of Plantago. This model underscores the potential importance of gene loss in the evolution of ecologically important traits. PMID:21282634

Preston, Jill C.; Martinez, Ciera C.; Hileman, Lena C.

2011-01-01

456

Regional Wind-Energy-Assessment Program. Progress report, October 1981September 1982  

Microsoft Academic Search

The research activities done in FY 1982 on the Regional Wind Energy Assessment Program are described. This includes work completed in large area wind power prospecting and data collection and analysis. The discussion of wind data analysis includes the wind data network, climatological wind speed and energy analysis, and wind statistical analysis. Also discussed is a wind power prospecting helicopter

R. W. Baker; J. E. Wade; P. O. G. Persson

1982-01-01

457

Counter-Flow Cooling Tower Test Cell  

NASA Astrophysics Data System (ADS)

The article contains a design of a functional experimental model of a cross-flow mechanical draft cooling tower and the results and outcomes of measurements. This device is primarily used for measuring performance characteristics of cooling fills, but with a simple rebuild, it can be used for measuring other thermodynamic processes that take part in so-called wet cooling. The main advantages of the particular test cell lie in the accuracy, size, and the possibility of changing the water distribution level. This feature is very useful for measurements of fills of different heights without the influence of the spray and rain zone. The functionality of this test cell has been verified experimentally during assembly, and data from the measurement of common film cooling fills have been compared against the results taken from another experimental line. For the purpose of evaluating the data gathered, computational scripts were created in the MATLAB numerical computing environment. The first script is for exact calculation of the thermal balance of the model, and the second is for determining Merkel's number via Chebyshev's method.

Dvo?ák, Lukáš; Noži?ka, Ji?í

2014-03-01

458

TRANSMISSION TOWERS WITH LIGHTENING ARRESTORS ON HILL NORTH OF ELWHA ...  

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

TRANSMISSION TOWERS WITH LIGHTENING ARRESTORS ON HILL NORTH OF ELWHA POWERHOUSE. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

459

4. VIEW RECONSTRUCTED TOWER, LOOKING NNE. Philadelphia & Reading ...  

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

4. VIEW RECONSTRUCTED TOWER, LOOKING NNE. - Philadelphia & Reading Railroad, Pedestrian Suspension Bridge, Foot of Sixth Street at Schuylkill River (formerly spanned Philadelphia & Reading main line at Reading Depot), Reading, Berks County, PA

460

3. DETAIL OF WEST TOWER, LOOKING NE. Philadelphia & ...  

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

3. DETAIL OF WEST TOWER, LOOKING NE. - Philadelphia & Reading Railroad, Pedestrian Suspension Bridge, Foot of Sixth Street at Schuylkill River (formerly spanned Philadelphia & Reading main line at Reading Depot), Reading, Berks County, PA

461

39. BOILER HOUSE, COAL CONVEYOR LEADING FROM COAL TOWER No. ...  

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

39. BOILER HOUSE, COAL CONVEYOR LEADING FROM COAL TOWER No. 1 (WEST) (NOTE: COAL CARS No. 9 & 5 IN BACKGROUND) - Delaware County Electric Company, Chester Station, Delaware River at South end of Ward Street, Chester, Delaware County, PA

462

EXPERIMENTAL SIMULATION OF SINGLE AND MULTIPLE CELL COOLING TOWER PLUMES  

EPA Science Inventory

An experimental investigation was conducted to determine the dilution characteristics of single and multiple port buoyant discharges typical of modern natural and mechanical draft cooling towers. Simultaneous measurements of velocity and tracer concentration profiles were taken a...

463

5. VIEW TO SOUTH, SAMPLING BUILDING AND WATER TOWER. ...  

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

5. VIEW TO SOUTH, SAMPLING BUILDING AND WATER TOWER. - Vanadium Corporation of America (VCA) Naturita Mill, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

464

10. VIEW TO SOUTHEAST, SAMPLING BUILDING, FOUNDATION, WATER TOWER, AND ...  

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

10. VIEW TO SOUTHEAST, SAMPLING BUILDING, FOUNDATION, WATER TOWER, AND SKINNER SALT ROASTERS. - Vanadium Corporation of America (VCA) Naturita Mill, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

465

7. COOLING TOWER FROM ROOF. Hot Springs National Park, ...  

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

7. COOLING TOWER FROM ROOF. - Hot Springs National Park, Bathhouse Row, Quapaw Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

466

View of south tower looking north. Note inspection team suspended ...  

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

View of south tower looking north. Note inspection team suspended by basket from crane examining underside of deck at top of picture. - Sidney Lanier Bridge, Spanning Brunswick River, Brunswick, Glynn County, GA

467

18. STATIC TEST TOWER VIEW FROM REMOVABLE LEVEL DOWN ...  

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

18. STATIC TEST TOWER - VIEW FROM REMOVABLE LEVEL DOWN TOWARDS GANTRY CRANE AND THREE TEST CELLS. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL