Science.gov

Sample records for fan case materials

  1. Material development for fan blade containment casing

    NASA Astrophysics Data System (ADS)

    McMillan, A.

    2008-03-01

    This paper describes the physics reasoning and the engineering development process for the structured material system adopted for the containment system of the Trent 900 engine. This is the Rolls-Royce engine that powers the Airbus A380 double-decker aeroplane, which is on the point of entering service. The fan blade containment casing is the near cylindrical casing that surrounds the fan blades at the front of the engine. The fan blades provide the main part of the thrust of the engine; the power to the fan is provided through a shaft from the turbine. The fan is approximately three meters in diameter, with the tips of the blade travelling at a little over Mach speed. The purpose of the containment system is to catch and contain a blade in the extremely unlikely event of a part or whole blade becoming detached. This is known as a ''Fan Blade Off (FBO)'' event. The requirement is that no high-energy fragments should escape the containment system; this is essential to prevent damage to other engines or to the fuselage of the aircraft. Traditionally the containment system philosophy has been to provide a sufficiently thick solid metallic skin that the blade cannot penetrate. Obviously, this is heavy. A good choice of metal in this case is a highly ductile steel, which arrests the kinetic energy of the blade through plastic deformation, and possibly, a controlled amount of cracking. This is known as ''hard wall'' containment. More recently, to reduce weight, containment systems have incorporated a Kevlar fibre wrap. In this case, the thinner metallic wall provides some containment, which is backed up by the stretching of the Kevlar fibres. This is known as ''soft wall'' containment; but it suffers the disadvantage of requiring a large empty volume in the nacelle in to which to expand. For the Trent 900 engine, there was a requirement to make a substantial weight saving while still adopting a hard wall style of containment system. To achieve this, a hollow structured

  2. Design and Testing of Braided Composite Fan Case Materials and Components

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Pereira, J. Michael; Braley, Michael S.; Arnold, William a.; Dorer, James D.; Watson, William R/.

    2009-01-01

    Triaxial braid composite materials are beginning to be used in fan cases for commercial gas turbine engines. The primary benefit for the use of composite materials is reduced weight and the associated reduction in fuel consumption. However, there are also cost benefits in some applications. This paper presents a description of the braided composite materials and discusses aspects of the braiding process that can be utilized for efficient fabrication of composite cases. The paper also presents an approach that was developed for evaluating the braided composite materials and composite fan cases in a ballistic impact laboratory. Impact of composite panels with a soft projectile is used for materials evaluation. Impact of composite fan cases with fan blades or blade-like projectiles is used to evaluate containment capability. A post-impact structural load test is used to evaluate the capability of the impacted fan case to survive dynamic loads during engine spool down. Validation of these new test methods is demonstrated by comparison with results of engine blade-out tests.

  3. Characterization of Composite Fan Case Resins

    NASA Technical Reports Server (NTRS)

    Dvoracek, Charlene M.

    2004-01-01

    The majority of commercial turbine engines that power today s aircraft use a large fan driven by the engine core to generate thrust which dramatically increases the engine s efficiency. However, if one of these fan blades fails during flight, it becomes high energy shrapnel, potentially impacting the engine or puncturing the aircraft itself and thus risking the lives of passengers. To solve this problem, the fan case must be capable of containing a fan blade should it break off during flight. Currently, all commercial fan cases are made of either just a thick metal barrier or a thinner metal wall surrounded by Kevlar-an ultra strong fiber that elastically catches the blade. My summer 2004 project was to characterize the resins for a composite fan case that will be lighter and more efficient than the current metal. The composite fan case is created by braiding carbon fibers and injecting a polymer resin into the braid. The resin holds the fibers together, so at first using the strongest polymer appears to logically lead to the strongest fan case. Unfortunately, the stronger polymers are too viscous when melted. This makes the manufacturing process more difficult because the polymer does not flow as freely through the braid, and the final product is less dense. With all of this in mind, it is important to remember that the strength of the polymer is still imperative; the case must still contain blades with high impact energy. The research identified which polymer had the right balance of properties, including ease of fabrication, toughness, and ability to transfer the load to the carbon fibers. Resin deformation was studied to better understand the composite response during high speed impact. My role in this research was the testing of polymers using dynamic mechanical analysis and tensile, compression, and torsion testing. Dynamic mechanical analysis examines the response of materials under cyclic loading. Two techniques were used for dynamic mechanical analysis

  4. Active Vibration Reduction of Titanium Alloy Fan Blades (FAN1) Using Piezoelectric Materials

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin; Kauffman, Jeffrey; Duffy, Kirsten; Provenza, Andrew; Morrison, Carlos

    2010-01-01

    The NASA Glenn Research Center is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this paper, a digital resonant control technique emulating passive shunt circuits is used to demonstrate vibration reduction of FAN1 Ti real fan blade at the several target modes. Single-mode control and multi-mode control using one piezoelectric material are demonstrated. Also a conceptual study of how to implement this digital control system into the rotating fan blade is discussed.

  5. Advanced laser shearography inspection of turbo-fan engine composite fan cases

    NASA Astrophysics Data System (ADS)

    Lape, Dale; Newman, John W.; Craig, David

    1995-07-01

    Shearography inspection techniques have been developed and implemented for the inspection of aluminum honeycomb turbofan aircraft engine fan cases for the JT15D-5D. Shearography has yielded improved sensitivity to unbonds and throughput over ultrasonic techniques formerly used in the production inspection. This paper discusses vacuum stress shearography, test method verification on the JT15D-5D fan case and shearography data correlation with destructive evaluation of test parts.

  6. Effect of material uncertainties on dynamic analysis of piezoelectric fans

    NASA Astrophysics Data System (ADS)

    Srivastava, Swapnil; Yadav, Shubham Kumar; Mukherjee, Sujoy

    2015-04-01

    A piezofan is a resonant device that uses a piezoceramic material to induce oscillations in a cantilever beam. In this study, lumped-mass modelling is used to analyze a piezoelectric fan. Uncertainties are associated with the piezoelectric structures due to several reasons such as variation during manufacturing process, temperature, presence of adhesive layer between the piezoelectric actuator/sensor and the shim stock etc. Presence of uncertainty in the piezoelectric materials can influence the dynamic behavior of the piezoelectric fan such as natural frequency, tip deflection etc. Moreover, these quantities will also affect the performance parameters of the piezoelectric fan. Uncertainty analysis is performed using classical Monte Carlo Simulation (MCS). It is found that the propagation of uncertainty causes significant deviations from the baseline deterministic predictions, which also affect the achievable performance of the piezofan. The numerical results in this paper provide useful bounds on several performance parameters of the cooling fan and will enhance confidence in the design process.

  7. Damage-Tolerant Fan Casings for Jet Engines

    NASA Technical Reports Server (NTRS)

    2006-01-01

    All turbofan engines work on the same principle. A large fan at the front of the engine draws air in. A portion of the air enters the compressor, but a greater portion passes on the outside of the engine this is called bypass air. The air that enters the compressor then passes through several stages of rotating fan blades that compress the air more, and then it passes into the combustor. In the combustor, fuel is injected into the airstream, and the fuel-air mixture is ignited. The hot gasses produced expand rapidly to the rear, and the engine reacts by moving forward. If there is a flaw in the system, such as an unexpected obstruction, the fan blade can break, spin off, and harm other engine components. Fan casings, therefore, need to be strong enough to contain errant blades and damage-tolerant to withstand the punishment of a loose blade-turned-projectile. NASA has spearheaded research into improving jet engine fan casings, ultimately discovering a cost-effective approach to manufacturing damage-tolerant fan cases that also boast significant weight reduction. In an aircraft, weight reduction translates directly into fuel burn savings, increased payload, and greater aircraft range. This technology increases safety and structural integrity; is an attractive, viable option for engine manufacturers, because of the low-cost manufacturing; and it is a practical alternative for customers, as it has the added cost saving benefits of the weight reduction.

  8. National Transonic Facility Fan Blade prepreg material characterization tests

    NASA Technical Reports Server (NTRS)

    Klich, P. J.; Richards, W. H.; Ahl, E. L., Jr.

    1981-01-01

    The test program for the basic prepreg materials used in process development work and planned fabrication of the national transonic facility fan blade is presented. The basic prepreg materials and the design laminate are characterized at 89 K, room temperature, and 366 K. Characterization tests, test equipment, and test data are discussed. Material tests results in the warp direction are given for tensile, compressive, fatigue (tension-tension), interlaminar shear and thermal expansion.

  9. Impact Testing of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

    2001-01-01

    Before composite materials can be considered for use in the fan case of a commercial jet engine, the performance of a composite structure under blade-out loads needs to be demonstrated. The objective of this program is to develop an efficient test and analysis method for evaluating potential composite case concepts. Ballistic impact tests were performed on laminated glass/epoxy composites in order to identify potential failure modes and to provide data for analysis. Flat 7x7 in. panels were impacted with cylindrical titanium projectiles, and 15 in. diameter half-rings were impacted with wedge-shaped titanium projectiles. Composite failure involved local fiber fracture as well as tearing and delamination on a larger scale. A 36 in. diameter full-ring subcomponent was proposed for larger scale testing. Explicit, transient, finite element analyses were used to evaluate impact dynamics and subsequent global deformation for the proposed full-ring subcomponent test. Analyses on half-ring and quarter ring configurations indicated that less expensive smaller scale tests could be used to screen potential composite concepts when evaluation of local impact damage is the primary concern.

  10. Ballistic and Cyclic Rig Testing of Braided Composite Fan Case Structures

    NASA Technical Reports Server (NTRS)

    Watson, William R.; Roberts, Gary D.; Pereira, J. Michael; Braley, Michael S.

    2015-01-01

    FAA fan blade-out certification testing on turbofan engines occurs very late in an engine's development program and is very costly. It is of utmost importance to approach the FAA Certification engine test with a high degree of confidence that the containment structure will not only contain the high-energy debris, but that it will also withstand the cyclic loads that occur with engine spooldown and continued rotation as the non-running engine maintains a low rotor RPM due to forced airflow as the engine-out aircraft returns to an airport. Accurate rig testing is needed for predicting and understanding material behavior of the fan case structure during all phases of this fan blade-out event.

  11. Alluvial Fans on Titan Reveal Atmosphere and Surface Interactions and Material Transport

    NASA Astrophysics Data System (ADS)

    Radebaugh, J.; Ventra, D.; Lorenz, R. D.; Farr, T. G.; Kirk, R. L.; Hayes, A.; Malaska, M. J.; Birch, S.; Liu, Z. Y. C.; Lunine, J. I.; Barnes, J. W.; Le Gall, A. A.; Lopes, R. M. C.; Stofan, E. R.; Wall, S. D.; Paillou, P.

    2015-12-01

    Alluvial fans, important depositional systems that record how sediment is stored and moved on planetary surfaces, are found on the surface of Titan, a body of significantly different materials and process rates than Earth. As seen by Cassini's Synthetic Aperture Radar (SAR) images at 350 m resolution, fans on Titan are found globally and are variable in size, shape and relationship to adjacent landforms. Their morphologies and SAR characteristics, which reveal roughness, textural patterns and other material properties, show similarities with fans in Death Valley seen by SAR and indicate there are regions of high relative relief locally, in the Ganesa, Xanadu and equatorial mountain belt regions. The Leilah Fluctus fans near Ganesa are ~30 km x 15 km, similar to the largest Death Valley fans, and revealing mountainous topography adjacent to plains. Others have gentle slopes over hundreds of kilometers, as in the high southern latitude lakes regions or the Mezzoramia southern midlatitudes, where a fan system is 200 km x 150 km, similar to the Qarn Alam fan emerging into the Rub al Khali in Oman. Additionally, there is evidence for a range of particle sizes, from relatively coarse (~2 cm or more) to fine, revealing long-term duration and variability in erosion by methane rainfall and transport. Some features have morphologies consistent with proximality to high-relief source areas and highly ephemeral runoff, while others appear to draw larger catchment areas and are perhaps characterized by more prolonged episodes of flow. The presence of many fans indicates the longevity of rainfall and erosion in Titan's surface processes and reveals that sediment transport and the precipitation that drives it are strongly episodic. Alluvial fans join rivers, lakes, eroded mountains, sand dunes and dissolution features in the list of surface morphologies derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between the two planetary

  12. Broadband Fan Noise Prediction System for Turbofan Engines. Volume 3; Validation and Test Cases

    NASA Technical Reports Server (NTRS)

    Morin, Bruce L.

    2010-01-01

    Pratt & Whitney has developed a Broadband Fan Noise Prediction System (BFaNS) for turbofan engines. This system computes the noise generated by turbulence impinging on the leading edges of the fan and fan exit guide vane, and noise generated by boundary-layer turbulence passing over the fan trailing edge. BFaNS has been validated on three fan rigs that were tested during the NASA Advanced Subsonic Technology Program (AST). The predicted noise spectra agreed well with measured data. The predicted effects of fan speed, vane count, and vane sweep also agreed well with measurements. The noise prediction system consists of two computer programs: Setup_BFaNS and BFaNS. Setup_BFaNS converts user-specified geometry and flow-field information into a BFaNS input file. From this input file, BFaNS computes the inlet and aft broadband sound power spectra generated by the fan and FEGV. The output file from BFaNS contains the inlet, aft and total sound power spectra from each noise source. This report is the third volume of a three-volume set documenting the Broadband Fan Noise Prediction System: Volume 1: Setup_BFaNS User s Manual and Developer s Guide; Volume 2: BFaNS User s Manual and Developer s Guide; and Volume 3: Validation and Test Cases. The present volume begins with an overview of the Broadband Fan Noise Prediction System, followed by validation studies that were done on three fan rigs. It concludes with recommended improvements and additional studies for BFaNS.

  13. Impact Testing and Analysis of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

    2002-01-01

    The fan case in a jet engine is a heavy structure because of its size and because of the requirement that it contain a blade released during engine operation. Composite materials offer the potential for reducing the weight of the case. Efficient design, test, and analysis methods are needed to efficiently evaluate the large number of potential composite materials and design concepts. The type of damage expected in a composite case under blade-out conditions was evaluated using a subscale test in which a glass/epoxy composite half-ring target was impacted with a wedge-shaped titanium projectile. Fiber shearing occurred near points of contact between the projectile and target. Delamination and tearing occurred on a larger scale. These damage modes were reproduced in a simpler test in which flat glass/epoxy composites were impacted with a blunt cylindrical projectile. A surface layer of ceramic eliminated fiber shear fracture but did not reduce delamination. Tests on 3D woven carbon/epoxy composites indicated that transverse reinforcement is effective in reducing delamination. A 91 cm (36 in.) diameter full-ring sub-component was proposed for larger scale testing of these and other composite concepts. Explicit, transient, finite element analyses indicated that a full-ring test is needed to simulate complete impact dynamics, but simpler tests using smaller ring sections are adequate when evaluation of initial impact damage is the primary concern.

  14. Experimental Study on Frictional Vibration in Bearing Case of Centrifugal Fan

    NASA Astrophysics Data System (ADS)

    Fujii, Takeo; Nakagawa, Noritoshi

    In the operation of a centrifugal fan installed on a steel plate floor reinforced with steel frames, applied to the heated air recirculation for the paint drier plant, abnormal vibration of the fan was observed in the transient condition of the plant operation. In view of the complexity of the vibration on the fan at the site, an experimental study on the vibration characteristics was conducted by using an identical fan and a simulated steel plate floor. As a result, there were three characteristic vibration phenomena during heating-up or cooling-down operation. The instantaneous increase of vibration occurred when the bearing case was new and there was insufficient lubrication even on the concrete slab. The temporary increase of vibration in vertical direction was caused by raising or sinking of the floor and the fan base due to thermal expansion. And, the fluctuation of vibration in axial direction was caused by friction, which yielded when the bearing moved inside the bearing case due to thermal expansion or contraction of the shaft. It seems that this fluctuation was due to self-excited vibration by friction.

  15. Effect of casing treatment on performance of a two-stage high-pressure-ratio fan

    NASA Technical Reports Server (NTRS)

    Urasek, D. C.

    1979-01-01

    A two-stage fan, previously tested with a solid casing, was tested with a casing with circumferential grooves over the tips of both rotors (casing treatment). Tests were conducted at 80 and 100 percent of design speed with uniform flow. The casing treatment improved the flow range and stall margin significantly without changing the characteristics overall performance curves of total-pressure and efficiency as functions of weight flow, other than extending them to lower weight flows.

  16. Acoustic testing of a 1.5 pressure ratio low tip speed fan with casing tip bleed (QEP Fan B scale model)

    NASA Technical Reports Server (NTRS)

    Kazin, S. B.; Minzner, W. R.; Paas, J. E.

    1971-01-01

    A scale model of the bypass flow region of a 1.5 pressure ratio, single stage, low tip speed fan was tested with a rotor tip casing bleed slot to determine its effects on noise generation. The bleed slot was located 1/2 inch (1.3 cm) upstream of the rotor leading edge and was configured to be a continuous opening around the circumference. The bleed manifold system was operated over a range of bleed rates corresponding to as much as 6% of the fan flow at approach thrust and 4.25% of the fan flow at takeoff thrust. Acoustic results indicate that a bleed rate of 4% of the fan flow reduces the fan maximum approach 200 foot (61.0 m) sideline PNL 0.5 PNdB and the corresponding takeoff thrust noise 1.1 PNdB below the level with zero bleed. However, comparison of the standard casing (no bleed slot) and the slotted bleed casing with zero bleed shows that the bleed slot itself caused a noise increase.

  17. Investigation of Hygro-Thermal Aging on Carbon/Epoxy Materials for Jet Engine Fan Sections

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee W.; Roberts, Gary D.; Miller, Sandi G.; Pereira, J. Michael

    2011-01-01

    This poster summarizes 2 years of aging on E862 epoxy and E862 epoxy with triaxial braided T700s carbon fiber composite. Several test methods were used to characterize chemical, physical, and mechanical properties of both the resin and composite materials. The aging cycle that was used included varying temperature and humidity exposure. The goal was to evaluate the environmental effects on a potential jet engine fan section material. Some changes were noted in the resin which resulted in increased brittleness, though this did not significantly affect the tensile and impact test results. A potential decrease in compression strength requires additional investigation.

  18. A Study of Fan Stage/Casing Interaction Models

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles; Carney, Kelly; Gallardo, Vicente

    2003-01-01

    The purpose of the present study is to investigate the performance of several existing and new, blade-case interactions modeling capabilities that are compatible with the large system simulations used to capture structural response during blade-out events. Three contact models are examined for simulating the interactions between a rotor bladed disk and a case: a radial and linear gap element and a new element based on a hydrodynamic formulation. The first two models are currently available in commercial finite element codes such as NASTRAN and have been showed to perform adequately for simulating rotor-case interactions. The hydrodynamic model, although not readily available in commercial codes, may prove to be better able to characterize rotor-case interactions.

  19. Study on the effects of flow in the volute casing on the performance of a sirocco fan

    NASA Astrophysics Data System (ADS)

    Adachi, Tsutomu; Sugita, Naohiro; Ohomori, Satoshi

    2004-08-01

    The flow at the exit from the runner blade of a centrifugal fan with forward curved blades (a sirocco fan) sometimes separates and becomes unstable. We have conducted many researches on the impeller shape of a sirocco fan, proper inlet and exit blade angles were considered to obtain optimum performance. In this paper, the casing shape were decided by changing the circumferential angle, magnifying angle and the width, 21 sorts of casings were used. Performance tests, inner flow velocity and pressure distributions were measured as well. Computational fluid dynamic calculations were also made and compared with the experimental results. Finally, the most suitable casing shape for best performance is considered.

  20. Penetrating head injury from a pedestal fan rotor blade in a child - an unusual case.

    PubMed

    Kumar, Arun; Singh, Hukum; Sharma, Karam Chand

    2006-01-01

    Penetrating head injuries in children constitute only a small part of the total number of traumatic head injuries seen in casualty. A number of household articles have been described to cause penetrating injuries, apart from gunshot and pellet injuries. We describe, for the first time, an unusual case of penetrating injury due to the rotor blade of pedestal fan used very commonly in the Indian subcontinent. PMID:17047422

  1. Singular case of shooting a football fan with a signal rocket.

    PubMed

    Kobek, M; Rygol, K; Chowaniec, C; Nowak, A

    2005-01-17

    The authors present a very rare case of fatal injuries resulting from shooting a parachute signal rocket with a hand operated launcher of signal pistol kind by pseudo-football fans. A 16-year-old football fan sustained extensive thermal burn of his lower extremities and abdomen, lacerated wound of his left thigh with a deep signal rocket-shot canal which caused injuries in subcutaneous tissue, fascia and both medial and posterior muscles of the thigh as well as injured both femoral vein and artery with subsequent hemorrhagic, burn and traumatic shocks. In spite of specialistic surgical treatment, the victim was not rescued. Analysis of medical documentation and our autopsy results were supplemented with an expert's opinion on physicochemical examinations supported by photographic documentation. PMID:15694727

  2. Alluvial fan sensitivity to glacial-interglacial climate change: case studies from Death Valley.

    NASA Astrophysics Data System (ADS)

    Whittaker, Alexander; D'Arcy, Mitch; Roda-Boluda, Duna; Brooke, Sam

    2016-04-01

    The effects of climate change on eroding landscapes and the sedimentary record remain poorly understood. The measurement of regional grain size trends in stream-flow deposits provides one way to address this issue because, in principle, these trends embed important information on the dynamics of sediment routing systems and their sensitivity to external forcings. In many cases, downstream stratigraphic fining is primarily driven by selective deposition of sediment. The relative efficiency of this process is determined by the physical characteristics of the input sediment supply and the spatial distribution of subsidence rate, which generates the accommodation necessary for mass extraction. Here, we measure grain size fining rates from apex to toe for alluvial fan systems in Death Valley, California, which have well-exposed modern and late Pleistocene deposits, where the long-term tectonic boundary conditions are known and where climatic variation over this time period is well-constrained. Our field data demonstrate that input grain sizes and input fining rates do vary noticeably over the late Pleistocene-Holocene period in this study area, although there is little evidence for significant changes in rates of faulting in the last 200 ky. For two catchments in the Grapevine Mountains for which we have excellent stratigraphic constraints on modern and 70 ka fan deposits, we use a self-similarity based grain size fining model to understand changes in sediment flux to the fans over this time period. When calibrated with cosmogenically-derived catchment erosion rates, our results show that a 30 % decrease in average precipitation rate over this time-frame led to a 20 % decrease in sediment flux to the fans, and a clear increase in the down-fan rate of fining. This supports existing landscape evolution models that relate a decrease in precipitation rate to a decrease in sediment flux, but implies that the relationship between sediment flux and precipitation rate may be

  3. Experimental Analysis of 3D Flow in Scroll Casing of Multi-Blade Fan for Air-Conditioner

    NASA Astrophysics Data System (ADS)

    Kitadume, Michio; Kawahashi, Masaaki; Hirahara, Hiroyuki; Uchida, Tadashi; Yanagawa, Hideki

    The multi-blade fan, which has been widely used as a blower for air-conditioning systems of vehicles, is one of the well-established fluid machinery. However, many factors must be considered in its practical design because the flow generated in the fan is quite complicated with three-dimensionality and unsteadiness. The fundamental fan performance is primarily determined by the impeller of the fan, and is also affected by the scroll casing. However, the theoretical estimation of the effect of the casing on the performance has not been well established. In order to estimate the casing effect on fan performance, detailed three-dimensional (3D) flow analysis in the casing is necessary. Stereoscopic PIV (SPIV) is one of the useful techniques for experimental analysis of 3D flow fields. There are some difficulties in practical application of SPIV for flow analysis in fluid machinery with complicated geometry, but the results obtained provide useful information for understanding the 3D flow field. In this report, experimental investigation of the flow in the scroll casing has been carried out using PIV and SPIV under the premise of downsizing automobile air conditioner fans.

  4. Towards a three-component model of fan loyalty: a case study of Chinese youth.

    PubMed

    Zhang, Xiao-xiao; Liu, Li; Zhao, Xian; Zheng, Jian; Yang, Meng; Zhang, Ji-qi

    2015-01-01

    The term "fan loyalty" refers to the loyalty felt and expressed by a fan towards the object of his/her fanaticism in both everyday and academic discourses. However, much of the literature on fan loyalty has paid little attention to the topic from the perspective of youth pop culture. The present study explored the meaning of fan loyalty in the context of China. Data were collected by the method of in-depth interviews with 16 young Chinese people aged between 19 and 25 years who currently or once were pop fans. The results indicated that fan loyalty entails three components: involvement, satisfaction, and affiliation. These three components regulate the process of fan loyalty development, which can be divided into four stages: inception, upgrade, zenith, and decline. This model provides a conceptual explanation of why and how young Chinese fans are loyal to their favorite stars. The implications of the findings are discussed. PMID:25886557

  5. Towards a Three-Component Model of Fan Loyalty: A Case Study of Chinese Youth

    PubMed Central

    Zhang, Xiao-xiao; Liu, Li; Zhao, Xian; Zheng, Jian; Yang, Meng; Zhang, Ji-qi

    2015-01-01

    The term “fan loyalty” refers to the loyalty felt and expressed by a fan towards the object of his/her fanaticism in both everyday and academic discourses. However, much of the literature on fan loyalty has paid little attention to the topic from the perspective of youth pop culture. The present study explored the meaning of fan loyalty in the context of China. Data were collected by the method of in-depth interviews with 16 young Chinese people aged between 19 and 25 years who currently or once were pop fans. The results indicated that fan loyalty entails three components: involvement, satisfaction, and affiliation. These three components regulate the process of fan loyalty development, which can be divided into four stages: inception, upgrade, zenith, and decline. This model provides a conceptual explanation of why and how young Chinese fans are loyal to their favorite stars. The implications of the findings are discussed. PMID:25886557

  6. Field performance of erosion resistant materials on boiler induced draft fan blades

    SciTech Connect

    Karr, O.F.; Brooks, J.B.; Seay, E.

    1993-05-01

    The TVA Kingston Fossil Power Plant has nine units and is located near Kingston, Tennessee. Units 1 through 4 have a rating of 148 MW and units 5 through 9 have a rating of 197 MW. Each unit has two induced draft fans manufactured by Westinghouse Electric Corp., Sturtevant Division. A table showing design data for the induced draft fans is located on page 16 of this report. The fan blade design details for units 5 through 9 are shown on pages 11 through 14. There is a mechanical fly ash collector and a small electrostatic precipitator preceding the induced draft fans in the boiler flue gas stream and a large, efficient electrostatic precipitator downstream of these fans. The steam generators and pulverizers were supplied by Combustion Engineering. The average temperature of the flue gas is about 340 degrees Fahrenheit for units 5 through 9. All induced draft fans in the boiler flue gas stream experience erosion from fly ash. When the precipitators and fly ash collectors were new the fan blades would last about three years before they were eroded severely and had to be replaced. Kingston Plant personnel say the fly ash collectors are presently in need of major repairs; therefore, the fan blades are not expected to last as long as they did when the plant was new.

  7. Application of composite materials to turbofan engine fan exit guide vanes

    NASA Technical Reports Server (NTRS)

    Smith, G. T.

    1980-01-01

    A program was conducted by NASA with the JT9D engine manufacturer to develop a lightweight, cost effective, composite material fan exit guide vane design having satisfactory structural durability for commerical engine use. Based on the results of a previous company supported program, eight graphite/epoxy and graphite-glass/epoxy guide vane designs were evaluated and four were selected for fabrication and testing. Two commercial fabricators each fabricated 13 vanes. Fatigue tests were used to qualify the selected design configurations under nominally dry, 38 C (100 F) and fully wet and 60 C (140 F) environmental conditions. Cost estimates for a production rate of 1000 vanes per month ranged from 1.7 to 2.6 times the cost of an all aluminum vane. This cost is 50 to 80 percent less than the initial program target cost ratio which was 3 times the cost of an aluminum vane. Application to the JT9D commercial engine is projected to provide a weight savings of 236 N (53 lb) per engine.

  8. A novel personal cooling system (PCS) incorporated with phase change materials (PCMs) and ventilation fans: An investigation on its cooling efficiency.

    PubMed

    Lu, Yehu; Wei, Fanru; Lai, Dandan; Shi, Wen; Wang, Faming; Gao, Chuansi; Song, Guowen

    2015-08-01

    Personal cooling systems (PCS) have been developed to mitigate the impact of severe heat stress for humans working in hot environments. It is still a great challenge to develop PCSs that are portable, inexpensive, and effective. We studied the performance of a new hybrid PCS incorporating both ventilation fans and phase change materials (PCMs). The cooling efficiency of the newly developed PCS was investigated on a sweating manikin in two hot conditions: hot humid (HH, 34°C, 75% RH) and hot dry (HD, 34°C, 28% RH). Four test scenarios were selected: fans off with no PCMs (i.e., Fan-off, the CONTROL), fans on with no PCMs (i.e., Fan-on), fans off with fully solidified PCMs (i.e., PCM+Fan-off), and fans on with fully solidified PCMs (i.e., PCM+Fan-on). It was found that the addition of PCMs provided a 54∼78min cooling in HH condition. In contrast, the PCMs only offered a 19-39min cooling in HD condition. In both conditions, the ventilation fans greatly enhanced the evaporative heat loss compared with Fan-off. The hybrid PCS (i.e., PCM+Fan-on) provided a continuous cooling effect during the three-hour test and the average cooling rate for the whole body was around 111 and 315W in HH and HD conditions, respectively. Overall, the new hybrid PCS may be an effective means of ameliorating symptoms of heat stress in both hot-humid and hot-dry environments. PMID:26267508

  9. Materials, Manufacturing and Test Development of a Composite Fan Blade Leading Edge Subcomponent for Improved Impact Resistance

    NASA Technical Reports Server (NTRS)

    Handschuh, Katherine M.; Miller, Sandi G.; Sinnott, Matthew J.; Kohlman, Lee W.; Roberts, Gary D.; Pereira, J. Michael; Ruggeri, Charles R.

    2014-01-01

    Application of polymer matrix composite materials for jet engine fan blades is becoming attractive as an alternative to metallic blades; particularly for large engines where significant weight savings are recognized on moving to a composite structure. However, the weight benefit of the composite of is offset by a reduction of aerodynamic efficiency resulting from a necessary increase in blade thickness; relative to the titanium blades. Blade dimensions are largely driven by resistance to damage on bird strike. Further development of the composite material is necessary to allow composite blade designs to approximate the dimensions of a metallic fan blade. The reduction in thickness over the state of the art composite blades is expected to translate into structural weight reduction, improved aerodynamic efficiency, and therefore reduced fuel consumption. This paper presents test article design, subcomponent blade leading edge fabrication, test method development, and initial results from ballistic impact of a gelatin projectile on the leading edge of composite fan blades. The simplified test article geometry was developed to realistically simulate a blade leading edge while decreasing fabrication complexity. Impact data is presented on baseline composite blades and toughened blades; where a considerable improvement to impact resistance was recorded.

  10. Materials, Manufacturing, and Test Development of a Composite Fan Blade Leading Edge Subcomponent for Improved Impact Resistance

    NASA Technical Reports Server (NTRS)

    Miller, Sandi G.; Handschuh, Katherine; Sinnott, Matthew J.; Kohlman, Lee W.; Roberts, Gary D.; Martin, Richard E.; Ruggeri, Charles R.; Pereira, J. Michael

    2015-01-01

    Application of polymer matrix composite materials for jet engine fan blades is becoming attractive as an alternative to metallic blades; particularly for large engines where significant weight savings are recognized on moving to a composite structure. However, the weight benefit of the composite is offset by a reduction of aerodynamic efficiency resulting from a necessary increase in blade thickness; relative to the titanium blades. Blade dimensions are largely driven by resistance to damage on bird strike. Further development of the composite material is necessary to allow composite blade designs to approximate the dimensions of a metallic fan blade. The reduction in thickness over the state of the art composite blades is expected to translate into structural weight reduction, improved aerodynamic efficiency, and therefore reduced fuel consumption. This paper presents test article design, subcomponent blade leading edge fabrication, test method development, and initial results from ballistic impact of a gelatin projectile on the leading edge of composite fan blades. The simplified test article geometry was developed to realistically simulate a blade leading edge while decreasing fabrication complexity. Impact data is presented on baseline composite blades and toughened blades; where a considerable improvement to impact resistance was recorded.

  11. A Case Report on the Effect of Fan Beam Thickness in Helical Tomotherapy of Nasopharyngeal Carcinoma

    SciTech Connect

    Wu, W.C. Vincent; Mui, Wing Lun A.

    2011-04-01

    The fan beam thickness (FBT) in helical tomotherapy is defined by a pair of collimators parallel to the rotational orbit of the radiation beam and is fixed for a specific patient treatment. The aim of this case study is to evaluate the dosimetric influence of changing the FBT in the treatment of a nasopharyngeal carcinoma (NPC) patient. The subject was a T2N1M0 stage NPC patient. The planning target volumes (PTVs) of the primary nasopharyngeal tumor and the left and right cervical lymphatics were delineated along with the organs at risk (OARs) in the corresponding computed tomography slices. Three treatment plans with FBT of 1.0 cm, 2.5 cm, and 5.0 cm (FBT-10, FBT-25, and FBT-50) were generated separately based on similar dose constraints and planning parameters. The dosimetric results of the PTV and OARs were collected and compared among the 3 treatment plans. The differences in the dose parameters of the PTVs were small among the 3 plans. The FBT-10 plan demonstrated the most homogeneous PTV doses with the smallest homogeneity indices (HIs). The FBT-50 plan delivered the highest dose to the OARs and the FBT-10 plan delivered the lowest. The differences between the 2 plans were more significant in the spinal cord, optic chiasm, optic nerves, and lens. This case study demonstrated that the variation of FBT in tomotherapy affected the quality of the treatment plan mainly in the OAR doses, but not so much in the PTV. Increasing the FBT reduced the effectiveness in the sparing of OARs.

  12. Impact Properties of Metal Fan Containment Materials Being Evaluated for the High-Speed Civil Transport (HSCT)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Under the Enabling Propulsion Materials (EPM) program - a partnership between NASA, Pratt & Whitney, and GE Aircraft Engines - the Materials and Structures Divisions of the NASA Lewis Research Center are involved in developing a fan-containment system for the High-Speed Civil Transport (HSCT). The program calls for a baseline system to be designed by the end of 1995, with subsequent testing of innovative concepts. Five metal candidate materials are currently being evaluated for the baseline system in the Structures Division's Ballistic Impact Facility. This facility was developed to provide the EPM program with cost-efficient and timely impact test data. At the facility, material specimens are impacted at speeds up to 350 m/sec by projectiles of various sizes and shapes to assess the specimens' ability to absorb energy and withstand impact. The tests can be conducted at either room or elevated temperatures. Posttest metallographic analysis is conducted to improve understanding of the failure modes. A dynamic finite element program is used to simulate the events and both guide the testing as well as aid in designing the fan-containment system.

  13. Uranium-series comminution ages of continental sediments: Case study of a Pleistocene alluvial fan

    SciTech Connect

    Lee, Victoria E.; DePaolo, Donald J.; Christensen, John N.

    2010-04-30

    Obtaining quantitative information about the timescales associated with sediment transport, storage, and deposition in continental settings is important but challenging. The uranium-series comminution age method potentially provides a universal approach for direct dating of Quaternary detrital sediments, and can also provide estimates of the sediment transport and storage timescales. (The word"comminution" means"to reduce to powder," reflecting the start of the comminution age clock as reduction of lithic parent material below a critical grain size threshold of ~;;50 mu m.) To test the comminution age method as a means to date continental sediments, we applied the method to drill-core samples of the glacially-derived Kings River Fan alluvial deposits in central California. Sediments from the 45 m core have independently-estimated depositional ages of up to ~;;800 ka, based on paleomagnetism and correlations to nearby dated sediments. We characterized sequentially-leached core samples (both bulk sediment and grain size separates) for U, Nd, and Sr isotopes, grain size, surface texture, and mineralogy. In accordance with the comminution age model, where 234U is partially lost from small sediment grains due to alpha recoil, we found that (234U/238U) activity ratios generally decrease with age, depth, and specific surface area, with depletions of up to 9percent relative to radioactive equilibrium. The resulting calculated comminution ages are reasonable, although they do not exactly match age estimates from previous studies and also depend on assumptions about 234U loss rates. The results indicate that the method may be a significant addition to the sparse set of available tools for dating detrital continental sediments, following further refinement. Improving the accuracy of the method requires more advanced models or measurements for both the recoil loss factor fa and weathering effects. We discuss several independent methods for obtaining fa on individual samples

  14. Identification of Net Recharge Rate Using Expert System - A Case Study of Choshuichi Alluvial Fan

    NASA Astrophysics Data System (ADS)

    Tsai, J. P.; Chang, L. C.; Chen, Y. W.; Chiang, C. J.; Huang, C. C.

    2012-04-01

    Conventionally, parameters identification of groundwater model can be classified into manual parametersidentification and automatic parameters identification using optimization method. Parameter searching in manualparameters identification requires heavily interaction with the modeler. Therefore, the identified parametersvalue is interpretable by the modeler. However, manual method is a complicated and time-consuming work and requires groundwater modeling practice and parameters identification experiences to performing the task. Optimization-based identification is more efficient and convenient comparing to the manual one. Nevertheless, the parameters search in the optimization approach can't directly interactive with modeler and one can only examine the final results. Moreover, because of the simplification of the optimization model, the parameters value obtained by optimization-based identification may not be feasible in reality. In light of previous discussion, this study integrates a rule-based expert system and a groundwater simulation model, MODFLOW 2000, to develop an automatic groundwater parameters identification system. We apply this proposed methodology to a real case study of Choshuihsi Alluvial Fan which is located at the central Taiwan. To test the robustness for high dimension problems, the proposed methodology is applied to calibrate the net recharge rates in a transient simulation in the study area. The result is compared with the calibration results obtained from UCODE. The results show that UCODE has difficulty converging to a global optimum in a high dimension situation and the initial guess dramatically effects the convergency of the optimization. Our proposed methodology is very robust for achieving the convergence requirements of output error criteria for high dimensional problems. These results presented the robustness and the applicability of the proposed methodology for high dimensional groundwater parameter identification problems.

  15. Detailed flow measurements in casing boundary layer of 429-meter-per-second-tip-speed two-stage fan

    NASA Technical Reports Server (NTRS)

    Gorrell, W. T.

    1984-01-01

    Detailed flow measurements between all blade rows were taken in the outer 30 percent of passage height of a two stage fan. Tabulations of the detailed flow measurements are included. Results of these measurements revealed the steep axial velocity profiles near the casing. The axial velocity profile near the casing at the rotor exists was much steeper than at the stator exits. The data also show overturning of the flow at the tip at the stator exits. The effect of mixing is shown by the redistribution of the first stage rotor exit total temperature profile as it passes through the following stator.

  16. New Whole-House Solutions Case Study: Evaluating Through-Wall Air Transfer Fans, Pittsburgh, Pennsylvania

    SciTech Connect

    2014-10-01

    In this project, Building America team IBACOS performed field testing in a new construction unoccupied test house in Pittsburgh, Pennsylvania, to evaluate heating, ventilating, and air conditioning (HVAC) distribution systems during heating, cooling, and midseason conditions. The team evaluated a market-available through-wall air transfer fan system that provides air to the bedrooms.The relative ability of this system was considered with respect to relevant Air Conditioning Contractors of America and ASHRAE standards for house temperature uniformity and stability.

  17. Two-stage fan. 3: Data and performance with rotor tip casing treatment, uniform and distorted inlet flows

    NASA Technical Reports Server (NTRS)

    Burger, G. D.; Hodges, T. R.; Keenan, M. J.

    1975-01-01

    A two stage fan with a 1st-stage rotor design tip speed of 1450 ft/sec, a design pressure ratio of 2.8, and corrected flow of 184.2 lbm/sec was tested with axial skewed slots in the casings over the tips of both rotors. The variable stagger stators were set in the nominal positions. Casing treatment improved stall margin by nine percentage points at 70 percent speed but decreased stall margin, efficiency, and flow by small amounts at design speed. Treatment improved first stage performance at low speed only and decreased second stage performance at all operating conditions. Casing treatment did not affect the stall line with tip radially distorted flow but improved stall margin with circumferentially distorted flow. Casing treatment increased the attenuation for both types of inlet flow distortion.

  18. Long-term interactions between man and the fluvial environment - case of the Diyala alluvial fan, Iraq

    NASA Astrophysics Data System (ADS)

    Heyvaert, Vanessa M. A.; Walstra, Jan; Mortier, Clément

    2014-05-01

    , during these periods (Parthian, Sasanian and again in modern times), significant human modification of the landscape took place. Periods of societal decline are associated with reduced human impact and the development of a single-threaded incising river system. Adams, R.M. (1965). Land behind Baghdad: A history of settlement on the Diyala plains. University of Chicago Press, Chicago, Illinois. Heyvaert, V.M.A. & Baeteman, C. (2008). A Middle to Late Holocene avulsion history of the Euphrates river: a case study from Tell ed-D-er, Iraq, Lower Mesopotamia. Quaternary Science Reviews, 27, 2401-2410. Heyvaert, V. M. A., Walstra, J., Verkinderen, P., Weerts, H. J. T. & Ooghe, B. (2012). The role of human interference on the channel shifting of the river Karkheh in the Lower Khuzestan plain (Mesopotamia, SW Iran). Quaternary International, 251, 52-63. Heyvaert, V.M.A., Walstra, J., Weerts, H.J.T. (2013). Human impact on avulsion and fan development in a semi-arid region: examples from SW Iran. Abstractbook of the 10th International Fluvial Sedimentology Conference, July 2013,Leeds, United Kingdom. Morozova, G.S. (2005). A review of Holocene avulsions of the Tigris and Euphrates rivers and possible effects on the evolution of civilizations in lower Mesopotamia. Geoarchaeology, 20, 401-423. Walstra, J., Heyvaert, V. M. A. & Verkinderen, P. (2010). Assessing human impact on alluvial fan development: a multidisciplinary case-study from Lower Khuzestan (SW Iran). Geodinamica Acta, 23, 267-285. Wilkinson, T.J. (2003). Archaeological Landscapes of the Near East. The University of Arizona Press, Tucson, Arizona.

  19. Building America Case Study: Evaluating Through-Wall Air Transfer Fans, Pittsburgh, Pennsylvania (Fact Sheet)

    SciTech Connect

    Not Available

    2014-10-01

    In this project, Building America team IBACOS performed field testing in a new construction unoccupied test house in Pittsburgh, Pennsylvania to evaluate heating, ventilating, and air conditioning (HVAC) distribution systems during heating, cooling, and midseason conditions. Four air-based HVAC distribution systems were assessed:-a typical airflow ducted system to the bedrooms, a low airflow ducted system to the bedrooms, a system with transfer fans to the bedrooms, and a system with no ductwork to the bedrooms. The relative ability of each system was considered with respect to relevant Air Conditioning Contractors of America and ASHRAE standards for house temperature uniformity and stability, respectively.

  20. Fan Noise Reduction: An Overview

    NASA Technical Reports Server (NTRS)

    Envia, Edmane

    2001-01-01

    Fan noise reduction technologies developed as part of the engine noise reduction element of the Advanced Subsonic Technology Program are reviewed. Developments in low-noise fan stage design, swept and leaned outlet guide vanes, active noise control, fan flow management, and scarfed inlet are discussed. In each case, a description of the method is presented and, where available, representative results and general conclusions are discussed. The review concludes with a summary of the accomplishments of the AST-sponsored fan noise reduction research and a few thoughts on future work.

  1. Noise and noise abatement in fans and blowers: A review

    NASA Astrophysics Data System (ADS)

    Neise, W.

    1980-03-01

    Noise generation and its reduction industrial fans (ventilators) is addressed. A review is given of the fan types commonly in use and their practical applications, the mechanisms of the aerodynamic noise generation in fans, theoretical and empirical prediction methods for fan noise, acoustic similarity laws, and noise reduction methods by means of the fan construction and fan operation. Measurement procedures are discussed with respect to the noise radiated from different parts of a fan, e.g. from the fan inlet or outlet, from the fan casing, from the fan as a whole, and to the noise radiated into ducts connected to the fan. Finally, considerations are made, for which classes of fans noise standards can be defined to characterize the noise emission of the various fan types.

  2. Fan Performance From Duct Rake Instrumentation on a 1.294 Pressure Ratio, 725 ft/sec Tip Speed Turbofan Simulator Using Vaned Passage Casing Treatment

    NASA Technical Reports Server (NTRS)

    Fite, E. Brian

    2006-01-01

    A 1.294 pressure ratio, 725 ft/sec tip speed, variable pitch low noise fan was designed and tested in the NASA Glenn 9- by 15-foot Wind Tunnel. The design included a casing treatment that used recirculation to extend the fan stall line and provide an acceptable operating range. Overall aerodynamic experimental results are presented for this low tip speed, low noise fan without casing treatment as well as using several variants of the casing treatment that moved the air extraction and insertion axial locations. Measurements were made to assess effects on performance, operability, and noise. An unusual instability was discovered near the design operating line and is documented in the fan operating range. Measurements were made to compare stall margin improvements as well as measure the performance impact of the casing treatments. Experimental results in the presence of simulated inlet distortion, via screens, are presented for the baseline and recirculation casing treatment configurations. Estimates are made for the quantity of recirculation weight flow based on limited instrumentation in the recirculation system along with discussion of results and conclusions

  3. Research Ethics. Cases and Materials.

    ERIC Educational Resources Information Center

    Penslar, Robin Levin, Ed.

    This book is a comprehensive resource of illustrative cases for classroom discussion of research ethics in the natural sciences, the behavioral sciences, and the humanities. The materials selected for inclusion are intended to speak to people in all disciplines, though the cases are drawn from biology, psychology, and history. They cover such…

  4. Layered Fan

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03692 Layered Fan

    This beautiful fan deposit is located at the end of a mega-gully that empties into the southern trough of Coprates Chasma.

    Image information: VIS instrument. Latitude -14.9N, Longitude 299.8E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. CF6 jet engine performance improvement: New fan

    NASA Technical Reports Server (NTRS)

    Fasching, W. A.

    1980-01-01

    As part of the NASA sponsored engine component improvement program, and fan package was developed to reduce fuel consumption in current CF6 turbofan aircraft engine. The new fan package consist of an improved fan blade, reduced fan tip clearance due to a fan case stiffener, and a smooth fan casing tip shroud. CF6 engine performance and acoustic tests demonstrated the predicted 1.8% improvement in cruise sfc without an increase in engine noise. Power management thrust/fan speed characteristics were defined. Mechanical and structural integrity was demonstrated in model fan rotor photoelastic stress tests, full-size fan blade bench fatigue tests, and CF6 engine bird ingestion, crosswind, and cyclic endurance tests. The fan was certified in the CF6-500c2/E2 engines and is in commerical service on the Boeing 747-200, Douglas DC-10-30, and Atrbus industrie A300B aircraft.

  6. FAN1 variants identified in multiple-case early-onset breast cancer families via exome sequencing: no evidence for association with risk for breast cancer.

    PubMed

    Park, Daniel J; Odefrey, Fabrice A; Hammet, Fleur; Giles, Graham G; Baglietto, Laura; ABCFS; MCCS; Hopper, John L; Schmidt, Daniel F; Makalic, Enes; Sinilnikova, Olga M; Goldgar, David E; Southey, Melissa C

    2011-12-01

    We are interested in the characterisation of previously undescribed contributions to the heritable component of human cancers. To this end, we applied whole-exome capture, followed by massively parallel sequence analysis to the germline DNA of two greater than third-degree affected relatives from four multiple-case, early-onset breast cancer families. Prior testing for variants in known breast cancer susceptibility, genes in these families did not identify causal mutations. We detected and confirmed two different variants in the DNA damage repair gene FAN1 (R377W, chr15:31197995 C>T and R507H, chr15:31202961 G>A [hg19]) which were not present in dbSNP131. In one family, FAN1 R377W, predicted to be damaging by SIFT and PolyPhen2, was present in all six tested members with cancer (five with breast cancer, one with malignant melanoma). In another family, FAN1 R507H, predicted to be damaging by SIFT but benign by PolyPhen2, was observed in one of two tested members with breast cancer. We genotyped FAN1 R377W and R507H variants across 1417 population-based cases and 1490 unaffected population-based controls (frequency-matched for age). These variants were rare in the Australian population (minor allele frequencies of 0.0064 and 0.010, respectively) and were not associated with breast cancer risk (OR = 0.80, 95% CI[0.39-1.61], P = 0.50 and OR = 0.74, 95% CI[0.41-1.29], P = 0.26, respectively). Analysis of breast cancer risks for relatives of case and control carriers did not find evidence of an increased risk. Despite the biological role of FAN1, the plausibility of its role as a breast cancer predisposition gene, and the possible deleterious nature of the identified variants, these two variants do not appear to be causal for breast cancer. Future studies to extend the genetic analysis of FAN1 will further explore its possible role as a breast cancer susceptibility gene. PMID:21858661

  7. Noise generated by quiet engine fans. 3: Fan C

    NASA Technical Reports Server (NTRS)

    Montegan, F. J.; Schaefer, J. W.; Schmiedlin, R. F.

    1976-01-01

    A family of fans designed with low noise features was acoustically evaluated, and noise results are documented for a 1.6-pressure-ratio, 472-m/sec (155-ft/sec) tip speed fan. The fan is described and some aerodynamic operating data are given. Far field noise around the fan was measured over a range of operating conditions for a variety of configurations having different arrangements of sound absorbing material in the flow ducts. Complete results of 1.3 octave band analysis of the data are presented in tabular form. Included also are acoustic power spectra and sideline perceived noise levels. Representative 1/3 octave band data are presented graphically, and sample graphs of continuous narrow band spectra are also provided.

  8. High-loading low-speed fan study. 4: Data and performance with redesign stator and including a rotor tip casing treatment

    NASA Technical Reports Server (NTRS)

    Harley, K. G.; Odegard, P. A.; Burdsall, E. A.

    1972-01-01

    A single stage fan with a rotor tip speed of 1000 ft/sec(304.8 m/sec) and a hub-to-tip ratio of 0.392 was retested with a redesigned stator. Tests were conducted with uniform inlet, tip-radial, hub-radial, and circumferential inlet distortions. With uniform inlet flow, stall margin was improved 12 percentage points above that with the original stator. The fan demonstrated an efficiency of 0.883 and a stall margin of 15 percent at a pressure ratio of 1.488 and a specific flow of 41.17 lb/sec/sq ft. Tests were also made with a redesigned casing treatment consisting of skewed slots over the rotor blade tips. This casing treatment gave a 7 percentage point improvement in stall margin when tested with tip radial distortion (when the rotor tip initiated stall). Noise measurements at the fan inlet and exit indicate no effect from closing the stator 10 degrees, nor were there measurable effects from adding skewed slots over the blade tips.

  9. 7. EXTERIOR VIEW OF BALTIMORE FAN HOUSE, AIRWAY, AND HILLMAN ...

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

    7. EXTERIOR VIEW OF BALTIMORE FAN HOUSE, AIRWAY, AND HILLMAN FAN HOUSE LOOKING SOUTHEAST The roof of the 1908 Baltimore Fan House is to the left; the doorway opens onto the rear of the metal fan housing. In the immediate foreground is a section of the blast doors installed in the airway directly over the shaft to protect the fans in case of a mine explosion. The sloping airway, to the right, connects with the New Fan House, whose metal updraft chimney is evident in the right background. The engine house of the Hillman Fan House is in the left background with the fan housing and updraft chimney connected. The boiler house stack is in the background. All of the engines in the fan complex were powered by the boiler house. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  10. Low Noise Research Fan Stage Design

    NASA Technical Reports Server (NTRS)

    Hobbs, David E.; Neubert, Robert J.; Malmborg, Eric W.; Philbrick, Daniel H.; Spear, David A.

    1995-01-01

    This report describes the design of a Low Noise ADP Research Fan stage. The fan is a variable pitch design which is designed at the cruise pitch condition. Relative to the cruise setting, the blade is closed at takeoff and opened for reverse thrust operation. The fan stage is a split flow design with fan exit guide vanes and core stators. This fan stage design was combined with a nacelle and engine core duct to form a powered fan/nacelle, subscale model. This model is intended for use in aerodynamic performance, acoustic and structural testing in a wind tunnel. The model has a 22-inch outer fan diameter and a hub-to-top ratio of 0.426 which permits the use of existing NASA fan and cowl force balance designs and rig drive system. The design parameters were selected to permit valid acoustic and aerodynamic comparisons with the PW 17-inch rig previously tested under NASA contract. The fan stage design is described in detail. The results of the design axisymmetric analysis at aerodynamic design condition are included. The structural analysis of the fan rotor and attachment is described including the material selections and stress analysis. The blade and attachment are predicted to have adequate low cycle fatigue life, and an acceptable operating range without resonant stress or flutter. The stage was acoustically designed with airfoil counts in the fan exit guide vane and core stator to minimize noise. A fan-FEGV tone analysis developed separately under NASA contract was used to determine these airfoil counts. The fan stage design was matched to a nacelle design to form a fan/nacelle model for wind tunnel testing. The nacelle design was developed under a separate NASA contract. The nacelle was designed with an axisymmetric inlet, cowl and nozzle for convenience in testing and fabrication. Aerodynamic analysis of the nacelle confirmed the required performance at various aircraft operating conditions.

  11. The Alternative Low Noise Fan

    NASA Technical Reports Server (NTRS)

    Dittmar, James H.; Elliott, David M.; Jeracki, Robert J.; Moore, Royce D.; Parrott, Tony L.

    2000-01-01

    A 106 bladed fan with a design takeoff tip speed of 1100 ft/sec was hypothesized as reducing perceived noise because of the shift of the blade passing harmonics to frequencies beyond the perceived noise rating range. A 22 in. model of this Alternative Low Noise Fan, ALNF, was tested in the NASA Glenn 9x 15 Wind Tunnel. 'Me fan was tested with a 7 vane long chord stator assembly and a 70 vane conventional stator assembly in both hard and acoustically treated configurations. In addition a partially treated 7 vane configuration was tested wherein the acoustic material between the 7 long chord stators was made inactive. The noise data from the 106 bladed fan with 7 long chord stators in a hard configuration was shown to be around 4 EPNdB quieter than a low tip speed Allison fan at takeoff and around 5 EPNdB quieter at approach. Although the tone noise behaved as hypothesized, the majority of this noise reduction was from reduced broadband noise related to the large number of rotor blades. This 106 bladed ALNF is a research fan designed to push the technology limits and as such is probably not a practical device with present materials technology. However, a low tip speed fan with around 50 blades would be a practical device and calculations indicate that it could be 2 to 3 EPNdB quieter at takeoff and 3 to 4 EPNdB quieter at approach than the Allison fan. 7 vane data compared with 70 vane data indicated that the tone noise was controlled by rotor wake-stator interaction but that the broadband noise is probably controlled by the interaction of the rotor with incoming flows. A possible multiple pure tone noise reduction technique for a fan/acoustic treatment system was identified. The data from the fully treated configuration showed significant noise reductions over a large frequency range thereby providing a real tribute to this bulk absorber treatment design. The tone noise data with the partially treated 7 vane configuration indicated that acoustic material in the

  12. Alluvial fans and fan deltas: a guide to exploration for oil and gas

    SciTech Connect

    Fraser, G.S.; Suttner, L.

    1986-01-01

    This volume is a result of a series of lectures presented to an oil company in 1985 and is intended for an audience of explorationists. Material is presented in the order in which an exploration program might proceed in a frontier area. The volume is divided into six chapters that cover definitions and tectonic setting, alluvial-fan morphology, processes and facies on alluvial fans, geomorphic controls, effects of extrinsic controls (chiefly tectonism and climate) on alluvial-fan sequences, and diagenesis. Previously published black-and-white line drawings from studies of modern and ancient fans and fan deltas provide almost all the illustrative material; only one photograph is included, an aerial view of fans in part of Death Valley. The authors emphasize the complexity and variability of fan deposits and their resultant architecture. Although the volume contains a useful review of previous literature, it contains little new material, and it is remarkably lacking subsurface examples and data for a volume intended for the exploration community. In addition, fan deltas receive only brief attention; the overwhelming part of the book is devoted to alluvial fans. The volume will be of interest to those involved in studies of modern and ancient alluvial-fan deposits. 165 references.

  13. Supersonic throughflow fans

    NASA Technical Reports Server (NTRS)

    Ball, C. L.; Moore, R. D.

    1988-01-01

    Supersonic throughflow fan research, and technology needs are reviewed. The design of a supersonic throughflow fan stage, a facility inlet, and a downstream diffuser is described. The results from the analysis codes used in executing the design are shown. An engine concept intended to permit establishing supersonic throughflow within the fan on the runway and maintaining the supersonic throughflow condition within the fan throughout the flight envelope is presented.

  14. Alluvial Fans on Mars

    NASA Technical Reports Server (NTRS)

    Kraal, E. R.; Moore, J. M.; Howard, A. D.; Asphaug, E. A.

    2005-01-01

    Moore and Howard [1] reported the discovery of large alluvial fans in craters on Mars. Their initial survey from 0-30 S found that these fans clustered in three distinct regions and occurred at around the +1 km MOLA defined Mars datum. However, due to incomplete image coverage, Moore and Howard [1]could not conduct a comprehensive survey. They also recognized, though did not quantitatively address, gravity scaling issues. Here, we briefly discuss the identification of alluvial fans on Mars, then consider the general equations governing the deposition of alluvial fans and hypothesize a method for learning about grain size in alluvial fans on Mars.

  15. Variable pitch fan system for NASA/Navy research and technology aircraft

    NASA Technical Reports Server (NTRS)

    Ryan, W. P.; Black, D. M.; Yates, A. F.

    1977-01-01

    Preliminary design of a shaft driven, variable-pitch lift fan and lift-cruise fan was conducted for a V/STOL Research and Technology Aircraft. The lift fan and lift-cruise fan employed a common rotor of 157.5 cm diameter, 1.18 pressure ratio variable-pitch fan designed to operate at a rotor-tip speed of 284 mps. Fan performance maps were prepared and detailed aerodynamic characteristics were established. Cost/weight/risk trade studies were conducted for the blade and fan case. Structural sizing was conducted for major components and weights determined for both the lift and lift-cruise fans.

  16. Engine cooling fan and fan shrouding arrangement

    SciTech Connect

    Longhouse, R.E.; Vona, N.

    1987-08-11

    This patent describes a vehicle engine cooling fan and shrouding assembly for forcing cooling air through a radiator in which engine coolant is circulated comprising support means adjacent to the radiator, a fan shroud and mounting shell operatively secured to the support means adjacent to the radiator. The shell has a peripheral forwardly extending wall portion to provide an intake for air flowing through the radiator. The shell further has a generally cylindrical and rearwardly extending portion to provide a reduced dimensioned air ejector for the shell, spoke means extending inwardly from the air ejector, a fan drive motor supported by the spoke means extending axially into the shell, the motor having a rotatable output shaft extending outwardly therefrom toward the radiator and having a terminal end portion, and engine cooling fan operatively driven by the drive motor and rotatably mounted in the shell.

  17. Deposystem architectures and lithofacies of a submarine fan-dominated deep sea succession in an orogen: A case study from the Upper Triassic Langjiexue Group of southern Tibet

    NASA Astrophysics Data System (ADS)

    Zhang, Chaokai; Li, Xianghui; Mattern, Frank; Mao, Guozheng; Zeng, Qinggao; Xu, Wenli

    2015-11-01

    Over thirty stratigraphic sections of the Himalaya orogen Upper Triassic Langjiexue Group in southern Tibet, China, were studied to interpret the environments and lithofacies. The facies associations channel (A), lobe (B), levee-interchannel (C), and basin plain (D) with nine facies (A1-3, B1-3, and C1-3) were distinguished. They form six architectural elements: channel-interchannel, overbank-levee, crevasse-splay, outer fan-lobe, fan-fringe, and basin plain. Taking into account the facies analysis, (sub-) deposystem correlation, paleocurrent dispersal pattern, and restoration of primary stratal width, the Langjiexue Group displays the architecture of a coalescing submarine fan-dominated deep sea deposystem, measuring about 400-500 km × 600-700 km in size or even more, one of the largest pre-Cenozoic submarine fans ever reported. Subdivisionally, four fans, lacking inner fans, could have coalesced laterally within the submarine fan deposystem, and at least six submarine fan developments were vertically succeeded by mid- to outer-fan deposits with progradational to retrogradational successions. According to the range of 30-70% of sandstone content, the fan deposystem is mud- and sand-rich, suggesting a medium-far (over 400-600 km) transport of sediment from the source area.

  18. Main fans for wood-gas systems: evaluation and design. Special report

    SciTech Connect

    Hose, F.R.

    1985-03-01

    The performance of a centrifugal fan, which had been successfully used as the main fan of a wood-gas system, was measured under a variety of test conditions. The aim of the tests was to derive a fan characteristic curve that allows the evaluation or prediction of fan performance under different circumstances. In addition, information on impeller materials have been included.

  19. Centrifugal fan monitoring guidelines

    SciTech Connect

    Piety, K.R.; Piety, R.W.; Greene, R.H.; Johnson, E.L. )

    1991-07-01

    This study provide guidelines on the vibration monitoring of centrifugal fans in fossil-fired utility plants. Based on an intensive analysis of a fan database, it provides a substantial amount of detailed information relating to vibration patterns and vibration amplitudes and recommends parameter bands and alarm levels. The study focuses on forced draft, induced draft, primary air, and gas recirculating fans. 8 refs., 19 figs., 19 tabs.

  20. The transfer of river load to deep-sea fans: A quantitative approach

    SciTech Connect

    Wetzel, A. )

    1993-10-01

    Submarine fans and turbidite systems are major petroleum reservoirs in many sedimentary basins worldwide. The size of a river-fed deep-sea fan is controlled mainly by the amount of sediment available from a terrestrial source, whereas sea level fluctuations only trigger mass transfer to the deep sea. The deposition rate and fan length correlate for most fans formed on abyssal plains. Fan size is independent of depositional environment (lake or sea), time span, or geological period, which may be characterized by different amplitudes and frequencies of sea level fluctuations. In climatically stable regions such as the tropics about 25 [+-] 10% of the suspended river load reaching the river mouth is transported to the deep sea over the long term. The type of river mouth affects the amount of material transported to the deep sea; estuaries with deeply incised canyons may transfer 6-8 times more material than fluvial-dominated and lobate deltas, provided the suspended river load is equal in both cases. For most river-fed deep-sea fans, a well-defined geometry develops on unconfined abyssal plains. The width/length ratio is about 0.2 at the base of the slope, and reaches a maximum of 0.5 farther downward. This is in good agreement with flume experiments. The volume of such fans resting on a planar base is roughly 0.35 [times] area [times] maximum thickness. The quantitative relationships of fans with respect to geometry, deposition rate, and river suspended discharge may provide some basic for basin modeling and calculation of the sediment budget of erosional-depositional systems.

  1. Civil protection non-structural measures in risk management on debris fan: a case study in Villarpellice (Italy)

    NASA Astrophysics Data System (ADS)

    Lazzari, A.; Conte, R.; Franzi, L.; Arattano, M.; Giordan, D.

    2009-04-01

    In the Piemonte region (Italy) the ideal sequence of steps that are pursued to manage, reduce or mitigate debris flow risk is followed by the regional Authorities in land planning activities. Generally practitioners, engineers, geologists and land planners are involved in this process because they have necessarily to interact among each other. In this frame, the collection of field data, the execution of field surveys and the application of hazard and risk mapping techniques to identify the debris flow prone areas on the debris fan allow decision makers to find the most profitable countermeasures to reduce the hazards and the risk, as well as to monitor the processes on the debris fan. The availability of time allows the government officers to elaborate also complex procedures and methods, and to widely discuss solutions with politicians, the general public and economists. In emergency situations, right after debris flow occurrence, similar procedures are generally followed to allow the authorities to take the most urgent decisions for risk and hazard management. However the lack of time often forces officers and decision makers to choose solutions to problems and to hazard mitigation much more quickly. Moreover, due to the complexity of the situations that have to be faced (assessment of the residual risk, project of countermeasures), the coordination of engineers, geologists and practitioners plays one of the most important roles in residual risk management. Land planning efficiency is less when the complexity of situation is high. Therefore, in emergency situations, simple and flexible criteria are generally to be preferred to complex ones. The paper discuss the procedures that need to be followed in emergency situations for a good documentation and an effective monitoring of debris flows and for the design of mitigation measures. In particular the paper shows the way the civil protection works in Piemonte region, on the base of the so-called AUGUSTUS approach

  2. 1. EXTERIOR VIEW OF NEW FAN HOUSE AND HILLMAN FAN ...

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

    1. EXTERIOR VIEW OF NEW FAN HOUSE AND HILLMAN FAN HOUSE LOOKING NORTHWEST The building on the left, the New Fan House, houses a Corliss steam engine which powered a Buffalo Forge Company single inlet Duplex Conoidal centrifugal exhausted fan through a metal updraft chimney. Part of the brick airway leading to the Baltimore shaft is visible to its right rear. The Hillman Fan House, on the right, houses the 1883 double inlet Guibal fan. The south entry, the curve of the fan housing, and brick updraft chimney are visible in this view. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  3. Engine component improvement: Performance improvement, JT9D-7 3.8 AR fan

    NASA Technical Reports Server (NTRS)

    Gaffin, W. O.

    1980-01-01

    A redesigned, fuel efficient fan for the JT9D-7 engine was tested. Tests were conducted to determine the effect of the 3.8 AR fan on performance, stability, operational characteristics, and noise of the JT9D-7 engine relative to the current 4.6 AR Bill-of-Material fan. The 3.8 AR fan provides increased fan efficiency due to a more advanced blade airfoil with increased chord, eliminating one part span shroud and reducing the number of fan blades and fan exit guide vanes. Engine testing at simulated cruise conditions demonstrated the predicted 1.3 percent improvement in specific fuel consumption with the redesigned 3.8 AR fan. Flight testing and sea level stand engine testing demonstrated exhaust gas temperature margins, fan and low pressure compressor stability, operational suitability, and noise levels comparable to the Bill-of-Material fan.

  4. Reason and Reaction: The Dual Route of Decision Making Process on Social Media Usage: The Case of Hospitality Brand Fan Pages

    ERIC Educational Resources Information Center

    Manthiou, Aikaterini

    2012-01-01

    A new phenomenon on Facebook, resulting from social media revolution, is the emergence of numerous Facebook fan pages. This form of online brand community is an effective tool for building relationships with consumers. Many hospitality firms (i.e. restaurants) have captured the strength of a fan page because it can enhance brand attractiveness and…

  5. Coastal alluvial fans (fan deltas) of the Gulf of Aqaba (Gulf of Eilat), Red Sea

    NASA Astrophysics Data System (ADS)

    Hayward, A. B.

    1985-04-01

    Coastal sediments of the Gulf of Aqaba are dominated by alluvial fans that prograde directly into the sea. The fans can be subdivided into four types: (1) largely inactive alluvial fans that merge into a braided fluvial system and pass seaward into sabkha flats, lagoons, mangroves and fringing reefs; (2) large alluvial fans that pass directly into the sea with one major entrenched channel and a fringing reef with a large incised canyon; both of these were formed during the Pleistocene, present fluvial activity is confined to the entrenched channels; (3) medium-sized (1-2 km long, 3-4 km wide) moderate to highly active alluvial fans with fringing reefs and backreef lagoons; and (4) small short-headed wadis that empty directly into the sea. The scale, overall sediment body geometry and facies associations of type (3) coastal alluvial fans (fan deltas) provide a close and useful modern analogue for many ancient fan-delta sedimentary sequences. On subaerial parts of the fan, disorganised cobbles and boulders, at the apex, deposited by debris flows pass downslope into longitudinal bars deposited during the high flood stage of periodic flash-flood events. The bars extend over the entire fan surface becoming progressively smaller and finer grained down fan. In general, the fans are characterised by a low proportion of floodplain deposits and extensive modification by aeolian processes, producing widespread gravel pavements and small dune fields over inactive areas of the lower fan. In the marine environment the fans are modified by a combination of wave action and longshore drift. Sand beaches are characterised by low-angle seaward-dipping lamination. On shingle beaches all gravel clasts have a strong preferred seaward dipping orientation. In areas where the fringing reefs are situated offshore from the fan, mixed quartz-bioclastic sand-filled lagoons develop. The nearshore lagoon areas are characterised by large sand bars orientated parallel to the shore. These pass

  6. Controls on alluvial fan long-profiles

    USGS Publications Warehouse

    Stock, J.D.; Schmidt, K.M.; Miller, D.M.

    2008-01-01

    Water and debris flows exiting confined valleys have a tendency to deposit sediment on steep fans. On alluvial fans where water transport of gravel predominates, channel slopes tend to decrease downfan from ???0.10-0.04 to ???0.01 across wide ranges of climate and tectonism. Some have argued that this pattern reflects grain-size fining downfan such that higher threshold slopes are required just to entrain coarser particles in the waters of the upper fan, whereas lower slopes are required to entrain finer grains downfan (threshold hypothesis). An older hypothesis is that slope is adjusted to transport the supplied sediment load, which decreases downfan as deposition occurs (transport hypothesis). We have begun to test these hypotheses for alluvial fan long-profiles using detailed hydraulic and particle-size data in sediment transport models. On four alluvial fans in the western U.S., we find that channel hydraulic radiiare largely 0.5-0.9 m at fan heads, decreasing to 0.1-0.2 m at distal margins. We find that median gravel diameter does not change systematically along the upper 60%-80% of active fan channels as slope declines, so downstream gravel fining cannot explain most of the observed channel slope reduction. However, as slope declines, channel-bed sand cover increases systematically downfan from areal fractions of <20% above fan heads to distal fan values in excess of 70%. As a result, entrainment thresholds for bed material might decrease systematically downfan, leading to lower slopes. However, current models of this effect alone tend to underpredict downfan slope changes. This is likely due to off-channel gravel deposition. Calculations that match observed fan long-profiles require an exponential decline in gravel transport rate, so that on some fans approximately half of the load must be deposited off channel every -0.20-1.4 km downfan. This leads us to hypothesize that some alluvial fan long-proffies are statements about the rate of overbank deposition of

  7. Fan Unit Physics

    NASA Astrophysics Data System (ADS)

    Morse, Robert A.

    2005-03-01

    A lightweight motor-driven propeller mounted on a low-friction cart provides a nearly constant thrust over a moderate range of velocities and can be a powerful pedagogical tool for investigating force and motion. A variety of homemade and commercial versions are now available. This article revisits and extends the topic of fan unit use described earlier. It looks at the rationale for use of fan units, gives examples of teaching ideas, and describes construction of two homemade versions of fan units.

  8. Impact resistance of composite fan blades

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Results are presented of a program to determine the impact resistance of composite fan blades subjected to foreign object damage (FOD) while operating under conditions simulating a short take-off and landing (STOL) engine at takeoff. The full-scale TF39 first-stage fan blade was chosen as the base design for the demonstration component since its configuration and operating tip speeds are similar to a typical STOL fan blade several composite configurations had already been designed and evaluated under previous programs. The first portion of the program was devoted toward fabricating and testing high impact resistant, aerodynamically acceptable composite blades which utilized only a single material system in any given blade. In order to increase the blade impact capability beyond this point, several mixed material (hybrid) designs were investigated using S-glass and Kevlar as well as boron and graphite fibers. These hybrid composite blades showed a marked improvement in resistance to bird impact over those blades made of a single composite material. The work conducted under this program has demonstrated substantial improvement in composite fan blades with respect to FOD resistance and has indicated that the hybrid design concept, which utilizes different types of fibers in various portions of a fan blade design depending on the particular requirements of the different areas and the characteristics of the different fibers involved, shows a significant improvement over those designs utilizing only one material system.

  9. OSCEE fan exhaust bulk absorber treatment evaluation

    NASA Technical Reports Server (NTRS)

    Bloomer, H. E.; Samanich, N. E.

    1980-01-01

    The acoustic suppression capability of bulk absorber material designed for use in the fan exhaust duct walls of the quiet clean short haul experiment engine (OCSEE UTW) was evaluated. The acoustic suppression to the original design for the engine fan duct which consisted of phased single degree-of-freedom wall treatment was tested with a splitter and also with the splitter removed. Peak suppression was about as predicted with the bulk absorber configuration, however, the broadband characteristics were not attained. Post test inspection revealed surface oil contamination on the bulk material which could have caused the loss in bandwidth suppression.

  10. Prototype Morphing Fan Nozzle Demonstrated

    NASA Technical Reports Server (NTRS)

    Lee, Ho-Jun; Song, Gang-Bing

    2004-01-01

    Ongoing research in NASA Glenn Research Center's Structural Mechanics and Dynamics Branch to develop smart materials technologies for aeropropulsion structural components has resulted in the design of the prototype morphing fan nozzle shown in the photograph. This prototype exploits the potential of smart materials to significantly improve the performance of existing aircraft engines by introducing new inherent capabilities for shape control, vibration damping, noise reduction, health monitoring, and flow manipulation. The novel design employs two different smart materials, a shape-memory alloy and magnetorheological fluids, to reduce the nozzle area by up to 30 percent. The prototype of the variable-area fan nozzle implements an overlapping spring leaf assembly to simplify the initial design and to provide ease of structural control. A single bundle of shape memory alloy wire actuators is used to reduce the nozzle geometry. The nozzle is subsequently held in the reduced-area configuration by using magnetorheological fluid brakes. This prototype uses the inherent advantages of shape memory alloys in providing large induced strains and of magnetorheological fluids in generating large resistive forces. In addition, the spring leaf design also functions as a return spring, once the magnetorheological fluid brakes are released, to help force the shape memory alloy wires to return to their original position. A computerized real-time control system uses the derivative-gain and proportional-gain algorithms to operate the system. This design represents a novel approach to the active control of high-bypass-ratio turbofan engines. Researchers have estimated that such engines will reduce thrust specific fuel consumption by 9 percent over that of fixed-geometry fan nozzles. This research was conducted under a cooperative agreement (NCC3-839) at the University of Akron.

  11. Containment of composite fan blades

    NASA Technical Reports Server (NTRS)

    Stotler, C. L.; Coppa, A. P.

    1979-01-01

    A lightweight containment was developed for turbofan engine fan blades. Subscale ballistic-type tests were first run on a number of concepts. The most promising configuration was selected and further evaluated by larger scale tests in a rotating test rig. Weight savings made possible by the use of this new containment system were determined and extrapolated to a CF6-size engine. An analytical technique was also developed to predict the released blades motion when involved in the blade/casing interaction process. Initial checkout of this procedure was accomplished using several of the tests run during the program.

  12. The Estimation of Hydraulic Conductivity Using Pumping Test Data and Vertical Electrical Sounding Measurements - A Case Study of Taiwan's Choshuihsi Alluvial Fan

    NASA Astrophysics Data System (ADS)

    Tsai, J.; Chang, P.; Chen, Y.; Chang, L.; Chiang, C.; Wang, Y.; Huang, C. C.; Chen, J.; Lin, H.

    2013-12-01

    Hydraulic conductivity (K) is an important aquifer parameter and is usually obtained using conventional pumping test. However, only a limited amount of data can be collected, because pumping tests are time consuming and expensive. In recent years, some studies estimated K by using pumping test data and surface electrical resistivity surveys. These studies cost less because less pumping tests are required. Linear regression is then applied to model the relationship between K and the formation factors. The problem is that most of these studies do not consider the effects caused by layers of clay. In fact, clay layers are commonly distributed in middle and distal fan. Therefore, this study divides the Zhuoshui River Alluvial Fan into several zones based on the sediment distribution. A linear regression equation is derived from the pumping test data and formation factors for each zone. This study applies these equations to develop the distribution of K in the shallow aquifer of the major fan. The result shows that the shallow aquifer of Zhuoshui River's major fan can be divided into two zones: top and non-top fan. The regression results show a good correlation between K and the formation factors in each zone. These regression equations are then used to estimate K in the study area. The estimation error is between 11m/day and 58m/day, which is in an acceptable range. The results of this study can be further applied to other analyses such as groundwater modeling or fluctuation methods.

  13. Noise generated by quiet engine fans. 1: FanB

    NASA Technical Reports Server (NTRS)

    Montegani, F. J.

    1972-01-01

    Acoustical tests of full scale fans for jet engines are presented. The fans are described and some aerodynamic operating data are given. Far field noise around the fan was measured for a variety of configurations over a range of operating conditions. Complete results of one third octave band analysis are presented in tabular form. Power spectra and sideline perceived noise levels are included.

  14. An Assessment of Current Fan Noise Prediction Capability

    NASA Technical Reports Server (NTRS)

    Envia, Edmane; Woodward, Richard P.; Elliott, David M.; Fite, E. Brian; Hughes, Christopher E.; Podboy, Gary G.; Sutliff, Daniel L.

    2008-01-01

    In this paper, the results of an extensive assessment exercise carried out to establish the current state of the art for predicting fan noise at NASA are presented. Representative codes in the empirical, analytical, and computational categories were exercised and assessed against a set of benchmark acoustic data obtained from wind tunnel tests of three model scale fans. The chosen codes were ANOPP, representing an empirical capability, RSI, representing an analytical capability, and LINFLUX, representing a computational aeroacoustics capability. The selected benchmark fans cover a wide range of fan pressure ratios and fan tip speeds, and are representative of modern turbofan engine designs. The assessment results indicate that the ANOPP code can predict fan noise spectrum to within 4 dB of the measurement uncertainty band on a third-octave basis for the low and moderate tip speed fans except at extreme aft emission angles. The RSI code can predict fan broadband noise spectrum to within 1.5 dB of experimental uncertainty band provided the rotor-only contribution is taken into account. The LINFLUX code can predict interaction tone power levels to within experimental uncertainties at low and moderate fan tip speeds, but could deviate by as much as 6.5 dB outside the experimental uncertainty band at the highest tip speeds in some case.

  15. Isotopic insights into smoothening of abandoned fan surfaces, Southern California

    USGS Publications Warehouse

    Matmon, A.; Nichols, K.; Finkel, R.

    2006-01-01

    Cosmogenic nuclide concentrations measured on abandoned fan surfaces along the Mojave section of the San Andreas Fault suggest that sediment is generated, transported, and removed from the fans on the order of 30-40??kyr. We measured in situ produced cosmogenic 10Be, and in some cases 26Al, in boulders (n??=??15), surface sediment (n??=??15), and one depth profile (n??=??9). Nuclide concentrations in surface sediments and boulders underestimate fan ages, suggesting that 10Be accumulation is largely controlled by the geomorphic processes that operate on the surfaces of the fans and not by their ages. Field observations, grain-size distribution, and cosmogenic nuclide data suggest that over time, boulders weather into grus and the bar sediments diffuse into the adjacent swales. As fans grow older the relief between bars and swales decreases, the sediment transport rate from bars to swales decreases, and the surface processes that erode the fan become uniform over the entire fan surface. The nuclide data therefore suggest that, over time, the difference in 10Be concentration between bars and swales increases to a maximum until the topographic relief between bars and swales is minimized, resulting in a common surface lowering rate and common 10Be concentrations across the fan. During this phase, the entire fan is lowered homogeneously at a rate of 10-15??mm??kyr-1. ?? 2006 University of Washington.

  16. The Performance of a Vaneless Diffuser Fan

    NASA Technical Reports Server (NTRS)

    Polikovsky, V.; Nevelson, M.

    1942-01-01

    The present paper is devoted to the theoretical and experimental investigation of one of the stationary elements of a fan, namely, the vaneless diffuser. The method of computation is based on the principles developed by Pfleiderer (Forschungsarbeiten No. 295). The practical interest of this investigation arises from the fact that the design of the fan guide elements - vaneless diffusers, guide vanes, spiral casing - is far behind the design of the impeller as regards accuracy and. reliability. The computations conducted by the method here presented have shown sufficiently good agreement with the experimental data and indicate the limits within which the values of the coefficient of friction lie.

  17. A fan tale, modern and ancient fans - A comparison

    SciTech Connect

    Fischer, P.J. ); Thor, D.R. ); Cherven, V.B.

    1991-02-01

    The Quaternary Conception fan of the Santa Barbara basin and the Upper Cretaceous Lathrop fan of the northern San Joaquin basin tell an interesting tale. Both fans show a well defined sequence stratigraphy of alternating low-stand, sand-rich units that alternate with thin high-stand silt units that drape and in-fill the surface topography of the previous sand-cycle. Isopachs made from detailed well log correlations (Lathrop) and seismic reflection data tied to borings (Conception) show that the fans are composed of a series of offset-stacked, elongate fan lobes. These lobes are similar in size. A major difference in the development of the two fans is the timing of tectonism. Concomitant tectonism uplifted the Conception fan lobes and resulted in localized erosion of high-stand silts beds and sand-on-sand lobe contacts. Tectonism and Lathrop occurred after fan deposition and provided the trapping structure-the Lathrop anticlinal fold. Following are some lessons to be learned from these and other fans the authors have studied: (1) Quaternary or modern' fans and ancient fans are similar. (2) Elongate sand-rich fan lobes separated by highstand silt units are typical of fans. (3) In addition to well-known techniques (seismic stratigraphy and detailed well log correlations), original reservoir pressures may be used to differentiate sequences and lobes (e.g., Lathrop). (4) Tectonism and erosion along the margin may limit traps to the uppermost lobe sequence (e.g., Conception). (5) An offset-stacked elongate fan lobe model is a valuable exploration and production tool.

  18. Centrifugal fans: Similarity, scaling laws, and fan performance

    NASA Astrophysics Data System (ADS)

    Sardar, Asad Mohammad

    Centrifugal fans are rotodynamic machines used for moving air continuously against moderate pressures through ventilation and air conditioning systems. There are five major topics presented in this thesis: (1) analysis of the fan scaling laws and consequences of dynamic similarity on modelling; (2) detailed flow visualization studies (in water) covering the flow path starting at the fan blade exit to the evaporator core of an actual HVAC fan scroll-diffuser module; (3) mean velocity and turbulence intensity measurements (flow field studies) at the inlet and outlet of large scale blower; (4) fan installation effects on overall fan performance and evaluation of fan testing methods; (5) two point coherence and spectral measurements conducted on an actual HVAC fan module for flow structure identification of possible aeroacoustic noise sources. A major objective of the study was to identity flow structures within the HVAC module that are responsible for noise and in particular "rumble noise" generation. Possible mechanisms for the generation of flow induced noise in the automotive HVAC fan module are also investigated. It is demonstrated that different modes of HVAC operation represent very different internal flow characteristics. This has implications on both fan HVAC airflow performance and noise characteristics. It is demonstrated from principles of complete dynamic similarity that fan scaling laws require that Reynolds, number matching is a necessary condition for developing scale model fans or fan test facilities. The physical basis for the fan scaling laws derived was established from both pure dimensional analysis and also from the fundamental equations of fluid motion. Fan performance was measured in a three times scale model (large scale blower) in air of an actual forward curved automotive HVAC blower. Different fan testing methods (based on AMCA fan test codes) were compared on the basis of static pressure measurements. Also, the flow through an actual HVAC

  19. Large Alluvial Fans on Mars

    NASA Technical Reports Server (NTRS)

    Moore, Jeffrey M.; Howard, Alan D.

    2004-01-01

    Several dozen distinct alluvial fans, 10 to greater than 40 km long downslope are observed exclusively in highlands craters. Within a search region between 0 deg. and 30 deg. S, alluvial fan-containing craters were only found between 18 and 29 S, and they all occur at around plus or minus 1 km of the MOLA-defined Martian datum. Within the study area they are not randomly distributed but instead form three distinct clusters. Fans typically descend greater than 1 km from where they disgorge from their alcoves. Longitudinal profiles show that their surfaces are very slightly concave with a mean slope of 2 degrees. Many fans exhibit very long, narrow low-relief ridges radially oriented down-slope, often branching at their distal ends, suggestive of distributaries. Morphometric data for 31 fans was derived from MOLA data and compared with terrestrial fans with high-relief source areas, terrestrial low gradient alluvial ramps in inactive tectonic settings, and older Martian alluvial ramps along crater floors. The Martian alluvial fans generally fall on the same trends as the terrestrial alluvial fans, whereas the gentler Martian crater floor ramps are similar in gradient to the low relief terrestrial alluvial surfaces. For a given fan gradient, Martian alluvial fans generally have greater source basin relief than terrestrial fans in active tectonic settings. This suggests that the terrestrial source basins either yield coarser debris or have higher sediment concentrations than their Martian counterpoints. Martian fans and Basin and Range fans have steeper gradients than the older Martian alluvial ramps and terrestrial low relief alluvial surfaces, which is consistent with a supply of coarse sediment. Martian fans are relatively large and of low gradient, similar to terrestrial fluvial fans rather than debris flow fans. However, gravity scaling uncertainties make the flow regime forming Martian fans uncertain. Martian fans, at least those in Holden crater, apparently

  20. Comparison of modern Mississippi fan with selected ancient fans

    SciTech Connect

    Shanmugam, G.; Moiola, R.J.; McPherson, J.G.; O'Connell, S.

    1988-09-01

    A comparison of the modern passive-margin Mississippi fan (DSDP Leg 96) with selected ancient active-margin fans reveals major differences in turbidite facies associations and seismic characteristics of the lower fan area. The lower Mississippi fan is composed of channel (facies B and F) and nonchannel sequences (facies C. and D), whereas lower fan areas of ancient active-margin fans are characterized by nonchannelized, thickening-upward depositional lobes (facies C and D) with sheetlike geometry. An absence of depositional lobes in the lower Mississippi fan is also suggested by a lack of mounded seismic reflections. Continuous and parallel seismic reflections of the lower Mississippi fan may represent sheet sands, but not those of true depositional lobes. In mature passive-margin fans, long, sinuous channels develop as a consequence of low gradients and the transport of sediment with a relatively low sand/mud ratio, and these channels develop lenticular sand bodies. In contrast, channels in active-margin fans are short and commonly braided as a result of high gradients and the transport of sediment with a relatively high sand/mud ratio. Braided channels characteristically develop sheetlike sand bodies.

  1. Jet Engine Fan Blade Containment Using an Alternate Geometry

    NASA Technical Reports Server (NTRS)

    Carney, K.S.; Pereira, J.M.; Revilock, D.M.; Matheny, P.

    2008-01-01

    With a goal of reducing jet engine weight, simulations of a fan blade containment system with an alternate geometry were tested and analyzed. A projectile simulating a fan blade was shot at two alternate geometry containment case configurations using a gas gun. The first configuration was a flat plate representing a standard case configuration. The second configuration was a flat plate with a radially convex curve section at the impact point. The curved surface was designed to force the blade to deform plastically, dissipating energy before the full impact of the blade is received by the plate. The curved case was able to tolerate a higher impact velocity before failure. The computational model was developed and correlated with the tests and a weight savings assessment was performed. For the particular test configuration used in this study the ballistic impact velocity of the curved plate was approximately 60 m/s (200 ft/s) greater than that of the flat plate. For the computational model to successfully duplicate the test, the very high strain rate behavior of the materials had to be incorporated.

  2. Acoustic analysis of a computer cooling fan

    NASA Astrophysics Data System (ADS)

    Huang, Lixi; Wang, Jian

    2005-10-01

    Noise radiated by a typical computer cooling fan is investigated experimentally and analyzed within the framework of rotor-stator interaction noise using point source formulation. The fan is 9 cm in rotor casing diameter and its design speed is 3000 rpm. The main noise sources are found and quantified; they are (a) the inlet flow distortion caused by the sharp edges of the incomplete bellmouth due to the square outer framework, (b) the interaction of rotor blades with the downstream struts which hold the motor, and (c) the extra size of one strut carrying electrical wiring. Methods are devised to extract the rotor-strut interaction noise, (b) and (c), radiated by the component forces of drag and thrust at the leading and higher order spinning pressure modes, as well as the leading edge noise generated by (a). By re-installing the original fan rotor in various casings, the noises radiated by the three features of the original fan are separated, and details of the directivity are interpreted. It is found that the inlet flow distortion and the unequal set of four struts make about the same amount of noise. Their corrections show a potential of around 10-dB sound power reduction.

  3. Noise reduction in fossil power plant draft fans

    SciTech Connect

    Koopmann, G.H.; Neise, W.

    1983-10-01

    Using a 20 in. dia fan noise testing facility, which was constructed at the University of Houston for this project, it has been demonstrated that a substantial reduction in the noise level of a centrifugal fan which has a pronounced tone can be achieved by incorporating a quarter-wavelength resonator in the fan casing near the cut-off part of the scroll. The resonator is tuned to the blade passing frequency of the fan by adjusting its length. It acts to reduce the level of the tonal component of the noise by cancelling the sound producing pressure pulses generated by the interaction of the fluid leaving the impeller blades with the solid cut-off of the fan casing. By proper tuning of the resonator and placement of the resonator's perforated mouth near the cut-off region where the pressure fluctuations are most intense, reductions of up to 20 dB in the sound pressure level of the blade passing frequency tone have been observed. Integration of the resonator into the fan casing design provides noise level reductions in both inlet and outlet ducts simultaneously. Reductions are independent of changes in duct impedance due to different end conditions. While the noise reduction method is effective over a wide range of aerodynamic loading conditions, it does not adversely affect the performance of the fan.

  4. Comparison of depositional elements of an ancient and a modern submarine fan complex: Early Pennsylvanian Jackfork and late Pleistocene Mississippi fans

    SciTech Connect

    Coleman, J.L. Jr. )

    1990-05-01

    Normark urged that all future, meaningful deep-sea fan comparisons be confined to key depositional elements common to most turbidite systems. These elements should include basin size, tectonic and eustatic setting, and depositional process indicators. A test case for elemental comparisons between two widely studied fan complexes is presented and evaluated. The lower Pennsylvanian (Morrowan) Jackfork submarine fan complex extends from central Arkansas to northeast Texas. Sequence analysis suggests that the Jackfork is composed of four to seven depositional episodes and occupies the floor of a deep basin bordered to the north and east by a passive carbonate-siliciclastic shelf margin and to the south and east by a northward-advancing orogenic belt. The Jackfork apparently unrestricted to the west and southwest. The Mississippi submarine fan complex extends from the submerged continental shelf of southern Louisiana to the abyssal depths between Yucatan and Florida. The fan complex is primarily Pleistocene in age, with the present morphologic fan being late Wisconsinian. The Mississippi Fan is composed of 17 depositional episodes. It occupies the floor of a deep basin bordered on the north and west by quiescent( ) halokinetic-siliciclastic shelf margins and to the east and south by passive carbonate margins. Elemental comparisons between the Mississippi fan and a palynspastically restored Jackfork fan complex suggest that both are quite similar, even though the Mississippi fan is up to three times larger in some categories. Comparative study of key depositional elements facilities a more complete understanding of both modern and ancient submarine fans.

  5. Development of a Fan for Future Space Suit Applications

    NASA Technical Reports Server (NTRS)

    Paul. Heather L.; Converse, David; Dionne, Steven; Moser, Jeff

    2010-01-01

    NASA's next generation space suit system will place new demands on the fan used to circulate breathing gas through the ventilation loop of the portable life support system. Long duration missions with frequent extravehicular activities (EVAs), the requirement for significant increases in reliability and durability, and a mission profile that imposes strict limits on weight, volume and power create the basis for a set of requirements that demand more performance than is available from existing fan designs. This paper describes the development of a new fan to meet these needs. A centrifugal fan was designed with a normal operating speed of approximately 39,400 rpm to meet the ventilation flow requirements while also meeting the aggressive minimal packaging, weight and power requirements. The prototype fan also operates at 56,000 rpm to satisfy a second operating condition associated with a single fan providing ventilation flow to two spacesuits connected in series. This fan incorporates a novel nonmetallic "can" to keep the oxygen flow separate from the motor electronics, thus eliminating ignition potential. The nonmetallic can enables a small package size and low power consumption. To keep cost and schedule within project bounds a commercial motor controller was used. The fan design has been detailed and implemented using materials and approaches selected to address anticipated mission needs. Test data is presented to show how this fan performs relative to anticipated ventilation requirements for the EVA portable life support system. Additionally, data is presented to show tolerance to anticipated environmental factors such as acoustics, shock, and vibration. Recommendations for forward work to progress the technology readiness level and prepare the fan for the next EVA space suit system are also discussed.

  6. 30 CFR 57.4504 - Fan installations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Installation/construction/maintenance § 57.4504 Fan installations. (a) Fan houses, fan bulkheads for main and booster fans, and air ducts connecting main fans to underground openings shall...

  7. 30 CFR 57.4504 - Fan installations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Installation/construction/maintenance § 57.4504 Fan installations. (a) Fan houses, fan bulkheads for main and booster fans, and air ducts connecting main fans to underground openings shall...

  8. Fan and pump noise control

    NASA Technical Reports Server (NTRS)

    Misoda, J.; Magliozzi, B.

    1973-01-01

    The development is described of improved, low noise level fan and pump concepts for the space shuttle. In addition, a set of noise design criteria for small fans and pumps was derived. The concepts and criteria were created by obtaining Apollo hardware test data to correlate and modify existing noise estimating procedures. A set of space shuttle selection criteria was used to determine preliminary fan and pump concepts. These concepts were tested and modified to obtain noise sources and characteristics which yield the design criteria and quiet, efficient space shuttle fan and pump concepts.

  9. Field of Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Subimage #1 Figure 1 Subimage #2 Figure 2 [figure removed for brevity, see original site] [figure removed for brevity, see original site] Anaglyph Figure 3 Subimage #3 Figure 4

    At the very beginning of spring in the southern hemisphere on Mars the ground is covered with a seasonal layer of carbon dioxide ice. In this image there are two lanes of undisturbed ice bordered by two lanes peppered with fans of dark dust.

    When we zoom in to the subimage (figure 1), the fans are seen to be pointed in the same direction, dust carried along by the prevailing wind. The fans seem to emanate from spider-like features.

    The second subimage (figure 2) zooms in to full HiRISE resolution to reveal the nature of the 'spiders.' The arms are channels carved in the surface, blanketed by the seasonal carbon dioxide ice. The seasonal ice, warmed from below, evaporates and the gas is carried along the channels. Wherever a weak spot is found the gas vents to the top of the seasonal ice, carrying along dust from below.

    The anaglyph (figure 3) of this spider shows that these channels are deep, deepening and widening as they converge. Spiders like this are often draped over the local topography and often channels get larger as they go uphill. This is consistent with a gas eroding the channels.

    A different channel morphology is apparent in the lanes not showing fans. In these regions the channels are dense, more like lace, and are not radially organized. The third subimage (figure 4) shows an example of 'lace.'

    Observation Geometry Image PSP_002532_0935 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 09-Feb-2007. The complete image is centered at -86.4 degrees latitude, 99.1 degrees East longitude. The range to the target site was 276.1 km (172.6 miles). At this distance the image scale is

  10. EXHAUST STACK RISES. STEEL FRAMEWORK FOR FAN HOUSE IN PLACE. ...

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

    EXHAUST STACK RISES. STEEL FRAMEWORK FOR FAN HOUSE IN PLACE. TRENCH IN FOREGROUND IS FOR DUCT THAT WILL CARRY COOLANT AIR FROM MTR'S THERMAL SHIELD. DUCT LINES UP WITH NORTH SIDE OF FAN HOUSE. AT RIGHT OF VIEW, NOTE TRENCH LEADING TO SOUTH SIDE OF FAN HOUSE; IT WILL BRING CONTAMINATED AIR FROM LABORATORY HOODS AND VENTS. CAMERA FACING EAST. INL NEGATIVE NO. 2764. Unknown Photographer, 6/29/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  11. Folding fan mode counter-current chromatography offers fast blind screening for drug discovery. Case study: finding anti-enterovirus 71 agents from Anemarrhena asphodeloides.

    PubMed

    Liu, Mengshun; Tao, Ling; Chau, Siu Leung; Wu, Rong; Zhang, Hong; Yang, Yifu; Yang, Dajian; Bian, Zhaoxiang; Lu, Aiping; Han, Quanbin; Xu, Hongxi

    2014-11-14

    A new application of counter-current chromatography (CCC) in drug discovery, called folding fan mode (FFM), is designed to eliminate the extensive and time-consuming calculation of the partition coefficients of some preset compounds in conventional CCC separation. Careful reading of reports in the literature reveals that, when two-phase solvent systems are listed in a polarity-increasing sequence, the isolates also show a similar trend in polarity. The relationship between the two-phase solvent system and the isolates is like that between the folds and the picture of a folding fan. We can directly select a two-phase solvent system to separate fractions having similar polarity, just as opening a fan reveals a picture. The solvent ratio of two-phase solvent systems can be adjusted according to the polarity and weight ratio of active fractions rather than the partition coefficients. Without preset compounds, FFM-CCC not only requires no measurement of partition coefficients, but also achieves true blind screening. This paper reports the method's first success in drug discovery: six anti-EV71 saponins were found from the mixture (9.13 g) of ethanol extract and water extract of Anemarrhena asphodeloides after a total of four CCC separations, using hexan/ethyl acetate/methanol/butanol/water as the model solvent system. Among these saponins, timosaponin B-II displayed a comparable IC50 (4.3 ± 2.1 μM) and a 40-fold higher selective index (SI=92.9) than the positive control (IC50=361.7 ± 104.6 μM, SI=2.4), ribavirin. The structure-activity relationship (SAR) of these compounds was also studied. PMID:25441347

  12. Bird impact analysis package for turbine engine fan blades

    NASA Technical Reports Server (NTRS)

    Hirschbein, M. S.

    1982-01-01

    A computer program has been developed to analyze the gross structural response of turbine engine fan blades subjected to bird strikes. The program couples a NASTRAN finite element model and modal analysis of a fan blade with a multi-mode bird impact analysis computer program. The impact analysis uses the NASTRAN blade model and a fluid jet model of the bird to interactively calculate blade loading during a bird strike event. The analysis package is computationaly efficient, easy to use and provides a comprehensive history of the gross structual blade response. Example cases are presented for a representative fan blade.

  13. Comprehensive Report of Fan Performance From Duct Rake Instrumentation on 1.294 Pressure Ratio, 806 ft/sec Tip Speed Turbofan Simulator Models

    NASA Technical Reports Server (NTRS)

    Jeracki, Robert J.

    2006-01-01

    A large scale model representative of an advanced ducted propulsor-type, low-noise, very high bypass ratio turbofan engine was tested for acoustics, aerodynamic performance, and off-design operability in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel. The test was part of NASA s Advanced Subsonic Technology Noise Reduction Program. The low tip speed fan, nacelle, and un-powered core passage were simulated. As might be expected, the effect of stall management casing treatment was a performance penalty. Reducing the recirculating flow at the fan tip reduced the penalty while still providing sufficient stall margin. Two fans were tested with the same aerodynamic design; one with graphite composite material, and the other with solid titanium. There were surprising performance differences between the two fans, though both blades showed some indication of transitional flow near the tips. Though the pressure and temperature ratios were low for this fan design, the techniques used to improve thermocouple measurement accuracy gave repeatable data with adiabatic efficiencies agreeing within 1 percent. The measured fan adiabatic efficiency at simulated takeoff conditions was 93.7 percent and matched the design intent.

  14. Arc Jet Testing of Thermal Protection Materials: 3 Case Studies

    NASA Technical Reports Server (NTRS)

    Johnson, Sylvia; Conley, Joe

    2015-01-01

    Arc jet testing is used to simulate entry to test thermal protection materials. This paper discusses the usefulness of arc jet testing for 3 cases. Case 1 is MSL and PICA, Case 2 is Advanced TUFROC, and Case 3 is conformable ablators.

  15. Regenerative Blower for EVA Suit Ventilation Fan

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Paul, Heather L.

    2010-01-01

    Portable life support systems in future space suits will include a ventilation subsystem driven by a dedicated fan. This ventilation fan must meet challenging requirements for pressure rise, flow rate, efficiency, size, safety, and reliability. This paper describes research and development that showed the feasibility of a regenerative blower that is uniquely suited to meet these requirements. We proved feasibility through component tests, blower tests, and design analysis. Based on the requirements for the Constellation Space Suit Element (CSSE) Portable Life Support System (PLSS) ventilation fan, we designed the critical elements of the blower. We measured the effects of key design parameters on blower performance using separate effects tests, and used the results of these tests to design a regenerative blower that will meet the ventilation fan requirements. We assembled a proof-of-concept blower and measured its performance at sub-atmospheric pressures that simulate a PLSS ventilation loop environment. Head/flow performance and maximum efficiency point data were used to specify the design and operating conditions for the ventilation fan. We identified materials for the blower that will enhance safety for operation in a lunar environment, and produced a solid model that illustrates the final design. The proof-of-concept blower produced the flow rate and pressure rise needed for the CSSE ventilation subsystem while running at 5400 rpm, consuming only 9 W of electric power using a non-optimized, commercial motor and controller and inefficient bearings. Scaling the test results to a complete design shows that a lightweight, compact, reliable, and low power regenerative blower can meet the performance requirements for future space suit life support systems.

  16. Regenerative Blower for EVA Suit Ventilation Fan

    NASA Technical Reports Server (NTRS)

    Paul, Heather; Izenson, Mike; Chen, Weibo

    2008-01-01

    Portable life support systems in future space suits will include a ventilation subsystem driven by a dedicated fan. This ventilation fan must meet challenging requirements for pressure rise, flow rate, efficiency, size, safety, and reliability. This paper describes research and development that showed the feasibility of a regenerative blower that is uniquely suited to meet these requirements. We proved feasibility through component tests, blower tests, and design analysis. Based on the requirements for the Constellation Space Suit ventilation fan, we designed the critical elements of the blower. We measured the effects of key design parameters on blower performance using separate effects tests, and used the results of these tests to design a regenerative blower that will meet the ventilation fan requirements. We assembled a proof-of-concept blower and measured its performance at low pressures that simulate a PLSS environment. We obtained head/flow performance curves over a range of operating speeds, identified the maximum efficiency point for the blower, and used these results to specify the design and operating conditions for the ventilation fan. We designed a compact motor that can drive the blower under all anticipated operating requirements and operate with high efficiency during normal operation. We identified materials for the blower that will enhance safety for operation in a lunar environment. We produced a solid model that illustrates the final design. The proof-of-concept blower produced the flow rate and pressure rise needed for the CSSS ventilation subsystem while running at 5400 rpm and consuming only 9 W of electric power and using a non-optimized, commercial motor and controller and inefficient bearings. Scaling the test results to a complete design shows that a lightweight, compact, reliable, and low power blower can meet the performance requirements for future PLSSs.

  17. Computational Aerodynamic Simulations of a Spacecraft Cabin Ventilation Fan Design

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    2010-01-01

    Quieter working environments for astronauts are needed if future long-duration space exploration missions are to be safe and productive. Ventilation and payload cooling fans are known to be dominant sources of noise, with the International Space Station being a good case in point. To address this issue cost effectively, early attention to fan design, selection, and installation has been recommended, leading to an effort by NASA to examine the potential for small-fan noise reduction by improving fan aerodynamic design. As a preliminary part of that effort, the aerodynamics of a cabin ventilation fan designed by Hamilton Sundstrand has been simulated using computational fluid dynamics codes, and the computed solutions analyzed to quantify various aspects of the fan aerodynamics and performance. Four simulations were performed at the design rotational speed: two at the design flow rate and two at off-design flow rates. Following a brief discussion of the computational codes, various aerodynamic- and performance-related quantities derived from the computed flow fields are presented along with relevant flow field details. The results show that the computed fan performance is in generally good agreement with stated design goals.

  18. Design features of fans, blowers, and compressors

    NASA Astrophysics Data System (ADS)

    Cheremisinoff, N. P.; Cheremisinoff, P. N.

    Fan engineering and compression machines are discussed. Basic aspects of fan performance and design are reviewed, and the design and performance characteristics of radial-flow fans, axial-flow fans, and controllable pitch fans are examined in detail. Air-conditioning systems are discussed, and noise, vibration, and mechanical considerations in fans are extensively examined. The thermodynamic principles governing compression machines are reviewed, and piston compressors, rotary compressors, blowers, and centrifugal compressors are discussed.

  19. Fan noise prediction assessment

    NASA Technical Reports Server (NTRS)

    Bent, Paul H.

    1995-01-01

    This report is an evaluation of two techniques for predicting the fan noise radiation from engine nacelles. The first is a relatively computational intensive finite element technique. The code is named ARC, an abbreviation of Acoustic Radiation Code, and was developed by Eversman. This is actually a suite of software that first generates a grid around the nacelle, then solves for the potential flowfield, and finally solves the acoustic radiation problem. The second approach is an analytical technique requiring minimal computational effort. This is termed the cutoff ratio technique and was developed by Rice. Details of the duct geometry, such as the hub-to-tip ratio and Mach number of the flow in the duct, and modal content of the duct noise are required for proper prediction.

  20. Quantitative Morphologic Analysis of Boulder Shape and Surface Texture to Infer Environmental History: A Case Study of Rock Breakdown at the Ephrata Fan, Channeled Scabland, Washington

    NASA Technical Reports Server (NTRS)

    Ehlmann, Bethany L.; Viles, Heather A.; Bourke, Mary C.

    2008-01-01

    Boulder morphology reflects both lithology and climate and is dictated by the combined effects of erosion, transport, and weathering. At present, morphologic information at the boulder scale is underutilized as a recorder of environmental processes, partly because of the lack of a systematic quantitative parameter set for reporting and comparing data sets. We develop such a parameter set, incorporating a range of measures of boulder form and surface texture. We use standard shape metrics measured in the field and fractal and morphometric classification methods borrowed from landscape analysis and applied to laser-scanned molds. The parameter set was pilot tested on three populations of basalt boulders with distinct breakdown histories in the Channeled Scabland, Washington: (1) basalt outcrop talus; (2) flood-transported boulders recently excavated from a quarry; and (3) flood-transported boulders, extensively weathered in situ on the Ephrata Fan surface. Size and shape data were found to distinguish between flood-transported and untransported boulders. Size and edge angles (approximately 120 degrees) of flood-transported boulders suggest removal by preferential fracturing along preexisting columnar joints, and curvature data indicate rounding relative to outcrop boulders. Surface textural data show that boulders which have been exposed at the surface are significantly rougher than those buried by fan sediments. Past signatures diagnostic of flood transport still persist on surface boulders, despite ongoing overprinting by processes in the present breakdown environment through roughening and fracturing in situ. Further use of this quantitative boulder parameter set at other terrestrial and planetary sites will aid in cataloging and understanding morphologic signatures of environmental processes.

  1. Constraining aggradation and degradation phases of alluvial fans in the sedimentary record: a case study from the Namib Desert, NW Namibia

    NASA Astrophysics Data System (ADS)

    von Hagke, Christoph; Malatesta, Luca C.; Ayoub, Francois; Stollhofen, Harald

    2015-04-01

    Along the Southern African margin it remains unclear whether the topography is the result of one or more Neogene uplift phases possibly related to mantle-driven dynamic topography, or a remnant of uplift due to pre-South Atlantic rifting and breakup during the Mesozoic. Whereas offshore seismic profiles and raised marine terraces onshore suggest phases of accelerated Neogene uplift, cosmogenic nuclide dating of river sediments and thermochronological data indicate constant uplift since post-Gondwana breakup. In this contribution we report present day erosion rate estimates from a fan-delta outboard the rift shoulder of the passive margin (i.e. the Great Escarpment), located in an area where erosion rate estimates on different timescales exist. Additionally, this fan-delta preserves elevated marine terraces on its surface, providing a unique time stratigraphic framework. It thus allows for direct comparison of erosion and uplift rate data as well as offshore-onshore correlation of sedimentary records. We constrain present day erosion rates of the system using quantitative sedimentology, and compare these results with published estimates of millennial and million year timescales. At present, erosion rates are 1.33E -06 mm/a, which is more than one order of magnitude lower than rates derived from cosmogenic nuclides, and several magnitudes lower than rates derived from thermochronological data. This shows that erosion rates constantly declined since the uplift pulse related to passive margin break-up. Subsequent erosional phases have not been effective enough to perturb this overall long-term trend. This is not in conflict with uplift rates inferred from raised beaches along the passive margin, if corrected for timescale dependent bias. With this study we are able to reconcile the confounding results from different data sets.

  2. Quantitative morphologic analysis of boulder shape and surface texture to infer environmental history: A case study of rock breakdown at the Ephrata Fan, Channeled Scabland, Washington

    NASA Astrophysics Data System (ADS)

    Ehlmann, Bethany L.; Viles, Heather A.; Bourke, Mary C.

    2008-05-01

    Boulder morphology reflects both lithology and climate and is dictated by the combined effects of erosion, transport, and weathering. At present, morphologic information at the boulder scale is underutilized as a recorder of environmental processes, partly because of the lack of a systematic quantitative parameter set for reporting and comparing data sets. We develop such a parameter set, incorporating a range of measures of boulder form and surface texture. We use standard shape metrics measured in the field and fractal and morphometric classification methods borrowed from landscape analysis and applied to laser-scanned molds. The parameter set was pilot tested on three populations of basalt boulders with distinct breakdown histories in the Channeled Scabland, Washington: (1) basalt outcrop talus; (2) flood-transported boulders recently excavated from a quarry; and (3) flood-transported boulders, extensively weathered in situ on the Ephrata Fan surface. Size and shape data were found to distinguish between flood-transported and untransported boulders. Size and edge angles (~120°) of flood-transported boulders suggest removal by preferential fracturing along preexisting columnar joints, and curvature data indicate rounding relative to outcrop boulders. Surface textural data show that boulders which have been exposed at the surface are significantly rougher than those buried by fan sediments. Past signatures diagnostic of flood transport still persist on surface boulders, despite ongoing overprinting by processes in the present breakdown environment through roughening and fracturing in situ. Further use of this quantitative boulder parameter set at other terrestrial and planetary sites will aid in cataloging and understanding morphologic signatures of environmental processes.

  3. High loading, low speed fan study, 5

    NASA Technical Reports Server (NTRS)

    Keenan, M. J.; Burdsall, E. A.

    1973-01-01

    A low speed, low noise, single stage fan was designed and tested. Design pressure ratio was 1.5 at a rotor tip speed of 1000 ft/sec. No inlet guide vane was used, the rotor stator was spaced and the number of rotor and stator airfoils was selected for low noise. Tests were conducted with uniform and distorted inlet flows. Stall margin of the initial design was too low for practical application. Airfoil slots and boundary layer and endwall devices did not improve stall margin sufficiently. A redesigned stator with reduced loadings increased stall margin, giving a fan efficiency of 0.883, 15% stall margin, and a 1.474 pressure radio at a specific flow of 41.7 lb/sec sq ft. Casing treatment over rotor tips improved stall margin with distorted inlet flow; vortex generators did not. Blade passing frequency noise increased with rotor relative Mach number. No supersonic fan noise was measured below 105% of design speed. Slotting airfoils, casing treatments, and a reduction of the ratio (number-stators/number-rotors) from (2n + 16) to (2n + 2) had no significant effects on noise.

  4. Quiet High-Speed Fan

    NASA Technical Reports Server (NTRS)

    Lieber, Lysbeth; Repp, Russ; Weir, Donald S.

    1996-01-01

    A calibration of the acoustic and aerodynamic prediction methods was performed and a baseline fan definition was established and evaluated to support the quiet high speed fan program. A computational fluid dynamic analysis of the NASA QF-12 Fan rotor, using the DAWES flow simulation program was performed to demonstrate and verify the causes of the relatively poor aerodynamic performance observed during the fan test. In addition, the rotor flowfield characteristics were qualitatively compared to the acoustic measurements to identify the key acoustic characteristics of the flow. The V072 turbofan source noise prediction code was used to generate noise predictions for the TFE731-60 fan at three operating conditions and compared to experimental data. V072 results were also used in the Acoustic Radiation Code to generate far field noise for the TFE731-60 nacelle at three speed points for the blade passage tone. A full 3-D viscous flow simulation of the current production TFE731-60 fan rotor was performed with the DAWES flow analysis program. The DAWES analysis was used to estimate the onset of multiple pure tone noise, based on predictions of inlet shock position as a function of the rotor tip speed. Finally, the TFE731-60 fan rotor wake structure predicted by the DAWES program was used to define a redesigned stator with the leading edge configured to minimize the acoustic effects of rotor wake / stator interaction, without appreciably degrading performance.

  5. Extended parametric representation of compressor fans and turbines. Volume 3: MODFAN user's manual (parametric modulating flow fan)

    NASA Technical Reports Server (NTRS)

    Converse, G. L.

    1984-01-01

    A modeling technique for single stage flow modulating fans or centrifugal compressors has been developed which will enable the user to obtain consistent and rapid off-design performnce from design point input. The fan flow modulation may be obtained by either a VIGV (variable inlet guide vane) or a VPF (variable pitch rotor) option. Only the VIGV option is available for the centrifugal compressor. The modeling technique has been incorporated into a time-sharing program to facilitate its use. Because this report contains a description of the input output data, values of typical inputs, and examples cases, it is suitable as a user's manual. This report is the last of a three volume set describing the parametric representation of compressor fans, and turbines. The titles of the three volumes are as follows: (1) Volume 1 CMGEN USER's Manual (Parametric Compressor Generator); (2) Volume 2 PART USER's Manual (Parametric Turbine); (3) Volume 3 MODFAN USER's Manual (Parametric Modulating Flow Fan).

  6. COOLING FAN AND SYSTEM PERFORMANCE AND EFFICIENCY IMPROVEMENTS

    SciTech Connect

    Ronald Dupree

    2005-07-31

    Upcoming emissions regulations (Tiers 3, 4a and 4b) are imposing significantly higher heat loads on the cooling system than lesser regulated machines. This work was a suite of tasks aimed at reducing the parasitic losses of the cooling system, or improving the design process through six distinct tasks: 1. Develop an axial fan that will provide more airflow, with less input power and less noise. The initial plan was to use Genetic Algorithms to do an automated fan design, incorporating forward sweep for low noise. First and second generation concepts could not meet either performance or sound goals. An experienced turbomachinery designer, using a specialized CFD analysis program has taken over the design and has been able to demonstrate a 5% flow improvement (vs 10% goal) and 10% efficiency improvement (vs 10% goal) using blade twist only. 2. Fan shroud developments, using an 'aeroshroud' concept developed at Michigan State University. Performance testing at Michigan State University showed the design is capable of meeting the goal of a 10% increase in flow, but over a very narrow operating range of fan performance. The goal of 10% increase in fan efficiency was not met. Fan noise was reduced from 0 to 2dB, vs. a goal of 5dB at constant airflow. The narrow range of fan operating conditions affected by the aeroshroud makes this concept unattractive for further development at this time 3. Improved axial fan system modeling is needed to accommodate the numbers of cooling systems to be redesigned to meet lower emissions requirements. A CFD fan system modeling guide has been completed and transferred to design engineers. Current, uncontrolled modeling practices produce flow estimates in some cases within 5% of measured values, and in some cases within 25% of measured values. The techniques in the modeling guide reduced variability to the goal of + 5% for the case under study. 4. Demonstrate the performance and design versatility of a high performance fan. A 'swept blade

  7. The Materials Division: A case study

    NASA Technical Reports Server (NTRS)

    Grisaffe, Salvatore J.; Lowell, Carl E.

    1989-01-01

    The Materials Division at NASA's Lewis Research Center has been engaged in a program to improve the quality of its output. The division, its work, and its customers are described as well as the methodologies developed to assess and improve the quality of the Division's staff and output. Examples of these methodologies are presented and evaluated. An assessment of current progress is also presented along with a summary of future plans.

  8. Quaternary migration of active extension revealed by a syn-tectonic alluvial fan shift. A case study in the Northern Apennines of Italy

    NASA Astrophysics Data System (ADS)

    Mirabella, Francesco; Bucci, Francesco; Cardinali, Mauro; Santangelo, Michele; Guzzetti, Fausto

    2016-04-01

    In areas characterized by the progressive migration of active extension through time, shifts in the position of the active depocenter occur. Such shifts through time produces peculiar geomorphological settings that are often characterized by wind gaps, abandoned valleys, streams captures and drainage inversions. These features provide the opportunity to investigate active areas by studying the recent-most geological history of the related nearby basins. We investigate this topic in a tectonically active area in the Northern Apennines of Italy, as indicated by both instrumental and historical seismicity (maximum epicentral intensity I0=VIII) and extension rates in the order of 2.5-2.7 mm/yr. In particular, we study the Montefalco ridge drainage inversion. Here, fluvial sands and imbricated conglomerates deposited in a lower Pleistocene depocenter constituted by an extensional subsiding basin, are presently uplifted more than 200 m above the present day alluvial plain. The Montefalco ridge drainage inversion, at about 400 m a.s.l., separates two valleys, the Gualdo Cattaneo - Bastardo valley to the West (300 m a.s.l.) and the Foligno present-day alluvial plain to the East (200 m a.s.l.). Seismic reflection data show that the maximum thickness of the continental sequence in the Foligno valley is in the order of 500 m. This valley is presently occupied by a 37 km2 alluvial fan produced by the Topino river flowing from NE to SW. To unravel the Quaternary tectonic evolution of the area, we integrate different data sets collected by field mapping, detailed photo-geological data, sediments provenance information, and subsurface data. We interpret the Montefalco ridge as a paleo-Foligno-like alluvial fan representing the evidence of the recent migration of the active extension to the East of around 7 km. Considering an age of deformation of 2.5 My, an extension rate of about 2.8 mm/yr is derived, which corresponds to the present-day geodetic rates. We stress the importance

  9. Containment of composite fan blades

    NASA Technical Reports Server (NTRS)

    Coppa, A. P.; Stotler, C. L.

    1977-01-01

    The development of containment concepts for use with large composite fan blades, taking into account the frangible nature of composite blades is considered. Aspects of the development program include; (1) an analysis to predict the interaction between a failed fan blade and the blade containment structure; (2) scaling factors to allow impact testing using subscale containment rings and simulated blades; (3) the design and fabrication of containment systems for further evaluation in a rotating rig test facility; (4) evaluate the test data against the analytically predicted results; and (5) determine overall systems weights and design characteristics of a composite fan stage installation and compare to the requirements of an equivalent titanium fan blade system. Progress in the blade impact penetration tests and the design and fabrication of blade containment systems is reported.

  10. Central Fan Integrated Ventilation Systems

    SciTech Connect

    2009-05-12

    This information sheet describes one example of a ventilation system design, a central fan integrated supply (CFIS) system, a mechanical ventilation and pollutant source control to ensure that there is reasonable indoor air quality inside the house.

  11. Vehicle hydraulic cooling fan system

    SciTech Connect

    Nilson, C.A.

    1993-06-08

    A hydraulic cooling system for vehicles having an internal combustion engine cooled by a radiator and a coolant is described, comprising, in combination, a shroud adapted to be mounted adjacent the radiator having a wall forming an air passage and defining a first port disposed adjacent the radiator and a second port spaced from the first port, a fan located within the second port, a hydraulic fan motor operatively connected to the fan, a hydraulic pump operatively connected to the engine for producing a pressurized hydraulic fluid flow, a hydraulic circuit interconnecting the pump to the fan motor, the circuit including a control valve, a hydraulic fluid reservoir and a heat exchanger, the heat exchanger being mounted within the shroud air passage.

  12. Hydraulic processes on alluvial fans

    SciTech Connect

    French, R.H.

    1987-01-01

    Alluvial fans are among the most prominent landscape features in the American Southwest and throughout the semi-arid and arid regions of the world. The importance of developing a qualitative and quantitative understanding of the hydraulic processes which formed, and which continue to modify, these features derives from their rapid and significant development over the past four decades. As unplanned urban sprawl moved from valley floors onto alluvial fans, the serious damage incurred from infrequent flow events has dramatically increased. This book presents a discussion of our current and rapidly expanding knowledge of hydraulic processes on alluvial fans. It addresses the subject from a multidisciplinary viewpoint, acquainting the reader with geological principles pertinent to the analysis of hydraulic processes on alluvial fans.

  13. Integral fan/water separator

    NASA Technical Reports Server (NTRS)

    Johnson, R. L.

    1976-01-01

    Centrifugal force created by rotating fan wheel separates moisture from gas. Lightweight portable unit can be worn with pressurized suit, where it will remove moisture that accumulates from breathing and perspiration.

  14. The Crati Submarine Fan, Ionian Sea

    USGS Publications Warehouse

    Lucchi, F.R.; Colella, A.; Gabbianelli, G.; Rossi, S.; Normark, W.R.

    1984-01-01

    The Crati Fan is located in the tectonically active submerged extension of the Apennines chain and foretrough. The small fan system is growing in a relatively shallow (200 to 450 m), elongate nearshore basin receiving abundant input from the Crati River. The fan is characterized by a short, steep, channelized section (inner or upper fan) and a smooth, slightly bulging distal section (outer or lower fan). The numerous subparallel channels head in the shelf or littoral zone and do not form branching distributary patterns. Sand and mud depositional lobes of the outer fan stretch over more than 60% of fan length. ?? 1984 Springer-Verlag New York Inc.

  15. Longitudinal study of aspergillosis in sea fan corals.

    PubMed

    Kim, Kiho; Alker, Alisa P; Shuster, Kara; Quirolo, Craig; Harvell, C Drew

    2006-03-23

    Aspergillosis (a fungal disease) is affecting sea fan corals Gorgonia spp. throughout the Caribbean. To measure the impact of this disease, we established longitudinal, or in other words individual-based, monitoring studies on 3 reefs in the Florida Keys, USA, to obtain estimates of incidence, rates of disease progress, recovery, and mortality. At Western Dry Rocks (near Key West), 40 Gorgonia ventalina colonies (20 initially healthy and 20 initially diseased) were photo-monitored between June 1996 and May 1998. Additional sea fans were visually monitored during 2 localized outbreaks at Conch (May 1998 to September 1999) and Carysfort (July 2000 to May 2001) reefs located in the Upper Keys. Data from Western Dry Rocks showed that over a 2 yr period, the incidence rate was 0.58 sea fans yr(-1) and that tissue purpling can lead to tissue loss and subsequently to mortality, albeit at low frequencies. Most sea fans, once infected, maintained a low level of damage over time. Only 3 fans recovered from the disease; however 2 were subsequently re-infected. Case fatality rate was 10% (2 of 20 initially infected died), which is equivalent to 5% yr(-1). However, mortality can increase during localized outbreaks. At Conch, mortality was 46% yr(-1) among infected sea fans (compared to 8% yr(-1) at Carysfort, a less impacted site, during the same period). During an outbreak at Carysfort, mortality was 95% yr(-1) among diseased sea fans. These data clearly demonstrate the significant role aspergillosis plays in the population ecology of sea fan corals. PMID:16703771

  16. A Method to Further Reduce the Perceived Noise of Low Tip Speed Fans

    NASA Technical Reports Server (NTRS)

    Dittmar, James H.

    2000-01-01

    The use of low tip speed, high bypass ratio fans is a method for reducing the noise of turbofan jet engines. These fans typically have a low number of rotor blades and a number of stator vanes sufficient to achieve cut-off of the blade passing tone. Their perceived noise levels are typically dominated by broadband noise caused by the rotor wake turbulence - stator interaction mechanism. A 106 bladed, 1100 ft/sec takeoff tip speed fan, the Alternative Low Noise Fan, has been tested and shown to have reduced broadband noise. This reduced noise is believed to be the result of the high rotor blade number. Although this fan with 106 blades would not be practical with materials as they exist today, a fan with 50 or so blades could be practically realized. A noise estimate has indicated that such a 50 bladed, low tip speed fan could be 2 to 3 EPNdB quieter than an 18 bladed fan. If achieved, this level of noise reduction would be significant and points to the use of a high blade number, low tip speed fan as a possible configuration for reduced fan noise.

  17. Environmental effects on FOD resistance of composite fan blade

    NASA Technical Reports Server (NTRS)

    Murphy, G. C.; Selemme, C. T.

    1981-01-01

    The sensitivity of the impact characteristics of typical polymeric composite fan blade materials to potential limiting combinations of moisture, temperature level and temperature transients was established. The following four technical tasks are reported: (1) evaluation and characterization of constituent blade materials; (2) ballistic impact tests; (3) leading edge impact protection systems; and (4) simulated blade spin impact tests.

  18. Large Well-exposed Alluvial Fans in Deep Late-Noachian Craters

    NASA Technical Reports Server (NTRS)

    Moore, J. M.; Howard, A.D.

    2004-01-01

    Large, fresh-appearing alluvial fans (typically greater than 10 km long) have been identified during a systematic search of 100 m/pixel low-sun daylight THEMIS IR imaging in deep late-Noachian or early- Hesperian craters. Our study of these fans was augmented with MOLA-derived topography and high-resolution MOC and THEMIS VIS images where available. The influence of alluvial fan deposition on the topography of crater floors has been recognized in previous topographic studies. Recent Mars Odyssey-era studies have also identified and described in detail a fluvial delta or fan of approximately the same age as the alluvial fans of this study. Our results, at the time of this writing, indicate that these fans are only found in less than 5% of all craters = 70 km in diameter within a large study region. In every case the fan-containing craters were restricted to a latitude belt between 20 deg S and 30 deg S. All of which had significant topographic relief and appeared morphologically younger than typical mid-Noachian craters in the size range. However, large fans were not found in the most pristine (and presumably youngest) craters in this size range. Most Martian fans have morphologies consistent with terrestrial debris-flow-dominated fans.

  19. Large Well-Exposed Alluvial Fans in Deep Late-Noachian Craters

    NASA Technical Reports Server (NTRS)

    Moore, J. M.; Howard, A. D.

    2004-01-01

    Large, fresh-appearing alluvial fans (typically greater than 10 km long) have been identified during a systematic search of 100 m/pixel low-sun daylight THEMIS IR imaging in deep late-Noachian or early-Hesperian craters. Our study of these fans was augmented with MOLA-derived topography and high-resolution MOC and THEMIS VIS images where available. The influence of alluvial fan deposition on the topography of crater floors has been recognized in previous topographic studies. Recent Mars Odyssey-era studies have also identified and described in detail a fluvial delta or fan of approximately the same age as the alluvial fans of this study. Our results, at the time of this writing, indicate that these fans are only found in less than 5% of all craters greater than or equal to 70 kilometers in diameter within a large study region. In every case the fan-containing craters were restricted to a latitude belt between 20 degrees S and 30 degrees S. All of which had significant topographic relief and appeared morphologically younger than typical mid-Noachian craters in the size range. However, large fans were not found in the most pristine (and presumably youngest) craters in this size range. Most Martian fans have morphologies consistent with terrestrial debris-flow-dominated fans.

  20. Developing, Implementing and Evaluating Case Studies in Materials Science

    ERIC Educational Resources Information Center

    Davis, Claire; Wilcock, Elizabeth

    2005-01-01

    The use of case studies to teach materials science undergraduates is an exciting and interesting educational approach. As well as helping learners to connect theory and practice, the case method is also useful for creating an active learning environment, developing key skills and catering for a range of different learning styles. This paper…

  1. Characterization of in-swath spray deposition for CP-11TT flat-fan nozzles used in low volume aerial application of crop production and protection materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For aerial application of crop production and protection materials, a complex interaction of controllable and uncontrollable factors is involved. It is difficult to completely characterize spray drift and deposition, but estimates can be made with appropriate sampling protocol and analysis. With c...

  2. Two-Stage Centrifugal Fan

    NASA Technical Reports Server (NTRS)

    Converse, David

    2011-01-01

    Fan designs are often constrained by envelope, rotational speed, weight, and power. Aerodynamic performance and motor electrical performance are heavily influenced by rotational speed. The fan used in this work is at a practical limit for rotational speed due to motor performance characteristics, and there is no more space available in the packaging for a larger fan. The pressure rise requirements keep growing. The way to ordinarily accommodate a higher DP is to spin faster or grow the fan rotor diameter. The invention is to put two radially oriented stages on a single disk. Flow enters the first stage from the center; energy is imparted to the flow in the first stage blades, the flow is redirected some amount opposite to the direction of rotation in the fixed stators, and more energy is imparted to the flow in the second- stage blades. Without increasing either rotational speed or disk diameter, it is believed that as much as 50 percent more DP can be achieved with this design than with an ordinary, single-stage centrifugal design. This invention is useful primarily for fans having relatively low flow rates with relatively high pressure rise requirements.

  3. Levitated Duct Fan (LDF) Aircraft Auxiliary Generator

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Emerson, Dawn C.; Gallo, Christopher A.; Thompson, William K.

    2011-01-01

    This generator concept includes a novel stator and rotor architecture made from composite material with blades attached to the outer rotating shell of a ducted fan drum rotor, a non-contact support system between the stator and rotor using magnetic fields to provide levitation, and an integrated electromagnetic generation system. The magnetic suspension between the rotor and the stator suspends and supports the rotor within the stator housing using permanent magnets attached to the outer circumference of the drum rotor and passive levitation coils in the stator shell. The magnets are arranged in a Halbach array configuration.

  4. 30 CFR 57.4131 - Surface fan installations and mine openings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Surface fan installations and mine openings. 57... Fire Prevention and Control Prohibitions/precautions/housekeeping § 57.4131 Surface fan installations and mine openings. (a) On the surface, no more than one day's supply of combustible materials shall...

  5. Dynamic bowtie for fan-beam CT.

    PubMed

    Liu, Fenglin; Wang, Ge; Cong, Wenxiang; Hsieh, Scott S; Pelc, Norbert J

    2013-01-01

    A bowtie is a filter used to shape an x-ray beam and equalize its flux reaching different detector channels. For development of spectral CT with energy discriminating photon-counting (EDPC) detectors, here we propose and evaluate a dynamic bowtie for performance optimization based on a patient model or a scout scan. With a mechanical rotation of a dynamic bowtie and an adaptive adjustment of an x-ray source flux, an x-ray beam intensity profile can be modulated. First, a mathematical model for dynamic bowtie filtering is established for an elliptical section in fan-beam geometry, and the contour of the optimal bowtie is derived. Then, numerical simulation is performed to compare the performance of the dynamic bowtie in the cases of an ideal phantom and a realistic cross-section relative to the counterparts without any bowtie and with a fixed bowtie respectively. Our dynamic bowtie can equalize the expected numbers of photons in the case of an ideal phantom. In practical cases, our dynamic bowtie can effectively reduce the dynamic range of detected signals inside the field of view. Although our design is optimized for an elliptical phantom, the resultant dynamic bowtie can be applied to a real fan-beam scan if the underlying cross-section can be approximated as an ellipse. Furthermore, our design methodology can be applied to specify an optimized dynamic bowtie for any cross-section of a patient, preferably using rapid prototyping technology. PMID:24191994

  6. Unstable flow in centrifugal fans

    SciTech Connect

    Chen, P.; Soundra-Nayagam, M.; Bolton, A.N.; Simpson, H.C.

    1996-03-01

    Rotating stall and the inlet vortex in centrifugal fans with inlet vane control has been studied. The advances in stall research in aero-engine compressors are discussed. The present study shows that stall in centrifugal fans can be quite different from that in axial compressors, in that stall can occur in a progressive and intermittent fashion. The study also shows that a discontinuity in the fan characteristic is not necessarily accompanied by rotating stall, unlike the axial machines. Experimental results indicate that the positive prewhirl created by inlet vanes tends to delay the occurrence of stall. Also, dorsal fin devices that are used to control the inlet vortex do not seem to affect the stall point unfavorably. The inlet vortex frequency was found to invariably exhibit a linear relation with the flow rate even when dorsal fins were used. This offers a practical method to distinguish between the inlet vortex and rotating stall.

  7. Fan Flutter Analysis Capability Enhanced

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Srivastava, Rakesh; Stefko, George L.

    2001-01-01

    The trend in the design of advanced transonic fans for aircraft engines has been toward the use of complex high-aspect-ratio blade geometries with a larger number of blades and higher loading. In addition, integrally bladed disks or blisks are being considered in fan designs for their potential to reduce manufacturing costs, weight, and complexity by eliminating attachments. With such design trends, there is an increased possibility within the operating region of part-speed stall flutter (self-excited vibrations) that is exacerbated by the reduced structural damping of blisk fans. To verify the aeroelastic soundness of the design, the NASA Glenn Research Center is developing and validating an accurate aeroelastic prediction and analysis capability. Recently, this capability was enhanced significantly as described here.

  8. Genes2FANs: connecting genes through functional association networks

    PubMed Central

    2012-01-01

    Background Protein-protein, cell signaling, metabolic, and transcriptional interaction networks are useful for identifying connections between lists of experimentally identified genes/proteins. However, besides physical or co-expression interactions there are many ways in which pairs of genes, or their protein products, can be associated. By systematically incorporating knowledge on shared properties of genes from diverse sources to build functional association networks (FANs), researchers may be able to identify additional functional interactions between groups of genes that are not readily apparent. Results Genes2FANs is a web based tool and a database that utilizes 14 carefully constructed FANs and a large-scale protein-protein interaction (PPI) network to build subnetworks that connect lists of human and mouse genes. The FANs are created from mammalian gene set libraries where mouse genes are converted to their human orthologs. The tool takes as input a list of human or mouse Entrez gene symbols to produce a subnetwork and a ranked list of intermediate genes that are used to connect the query input list. In addition, users can enter any PubMed search term and then the system automatically converts the returned results to gene lists using GeneRIF. This gene list is then used as input to generate a subnetwork from the user’s PubMed query. As a case study, we applied Genes2FANs to connect disease genes from 90 well-studied disorders. We find an inverse correlation between the counts of links connecting disease genes through PPI and links connecting diseases genes through FANs, separating diseases into two categories. Conclusions Genes2FANs is a useful tool for interpreting the relationships between gene/protein lists in the context of their various functions and networks. Combining functional association interactions with physical PPIs can be useful for revealing new biology and help form hypotheses for further experimentation. Our finding that disease genes in

  9. Vacuum Cleaner Fan Being Improved

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    1997-01-01

    As part of the technology utilization program at the NASA Lewis Research Center, efforts are underway to transfer aerospace technologies to new areas of practical application. One such effort involves using advanced computational fluid dynamics (CFD) codes for turbomachinery to analyze the internal fluid dynamics of low-speed fans and blowers. This year, the Kirby Company in Cleveland, Ohio, approached NASA with a request for technologies that could help them improve their vacuum cleaners. Of particular interest to Kirby is the high-frequency blade-passing noise generation of their vacuum cleaner fan at low airflow rates.

  10. Sound maintenance practices protect fan investments

    SciTech Connect

    Bauer, M.

    2009-11-15

    Since underground coal miners depend on axial fans, lack of maintenance could prove costly. A number of pre-emptive actions that can help keep fans running at optimal performance can also be taken. 2 photos.

  11. Prop-fan with improved stability

    NASA Technical Reports Server (NTRS)

    Rothman, Edward A. (Inventor); Violette, John A. (Inventor)

    1988-01-01

    Improved prop-fan stability is achieved by providing each blade of the prop-fan with a leading edge which, outwardly, from a location thereon at the mid-span of the blade, occupy generally a single plane.

  12. New observations of sinuous channels on the Amazon Fan

    NASA Astrophysics Data System (ADS)

    Flood, R. D.

    2014-12-01

    High-sinuosity submarine fan channels on the Amazon Fan were first observed using long-range (GLORIA) side-scan sonar in 1982 and mapped in greater detail using multibeam sonar in 1984. These data have provided important insights into the nature and evolution of submarine channel systems. Subsequent studies on the Amazon Fan have focused on avulsion patterns, sedimentation patterns, fan growth and the climate record contained in fan sediments, and there has been relatively little additional work on the details of sinuous channel morphology. Channels on the Amazon Fan have been imaged by multibeam sonar on several occasions since 1984 during focused studies, regional mapping and ship transit. These multibeam data are being compiled and studied to better characterize these iconic channels. One observation of particular interest is that, on the Amazon Fan, channel-wall slumps appear to be more common than previously thought. Drilling of a cut-off meander during ODP Leg 155 on the Amazon Fan showed the presence of slumped material deeper in the channel suggesting that failure of the channel wall was in part responsible for the abandonment and filling of that meander loop. The failure also apparently created a sandy debris flow with clasts of fine-grained levee material transported in a sandy matrix. This sandy debris flow may have been able to flow along the channel and deposit at the seaward end where similar sediments can be found. Disturbed zones now visible on the inner walls of channels at several other places along the channels suggest that these kinds of inner-wall slumps may play important roles in channel evolution and fan growth. Channel-blocking slumps can isolate channel loops which can then fill with sandy sediments, and avulsions are likely if this kind of slump fills the channel. The failure of channel walls can also lead to new channel segments that tend to straighten the channel. Dramatic changes to the shape of the channel can likely lead to large and

  13. Measurement of airflow and pressure characteristics of a fan built in a car ventilation system

    NASA Astrophysics Data System (ADS)

    Pokorný, Jan; Poláček, Filip; Fojtlín, Miloš; Fišer, Jan; Jícha, Miroslav

    2016-03-01

    The aim of this study was to identify a set of operating points of a fan built in ventilation system of our test car. These operating points are given by the fan pressure characteristics and are defined by a pressure drop of the HVAC system (air ducts and vents) and volumetric flow rate of ventilation air. To cover a wide range of pressure drops situations, four cases of vent flaps setup were examined: (1) all vents opened, (2) only central vents closed (3) only central vents opened and (4) all vents closed. To cover a different volumetric flows, the each case was measured at least for four different speeds of fan defined by the fan voltage. It was observed that the pressure difference of the fan is proportional to the fan voltage and strongly depends on the throttling of the air distribution system by the settings of the vents flaps. In case of our test car we identified correlations between volumetric flow rate of ventilation air, fan pressure difference and fan voltage. These correlations will facilitate and reduce time costs of the following experiments with this test car.

  14. Review of Aircraft Engine Fan Noise Reduction

    NASA Technical Reports Server (NTRS)

    VanZante, Dale

    2008-01-01

    Aircraft turbofan engines incorporate multiple technologies to enhance performance and durability while reducing noise emissions. Both careful aerodynamic design of the fan and proper installation of the fan into the system are requirements for achieving the performance and acoustic objectives. The design and installation characteristics of high performance aircraft engine fans will be discussed along with some lessons learned that may be applicable to spaceflight fan applications.

  15. Advance Noise Control Fan II: Test Rig Fan Risk Management Study

    NASA Technical Reports Server (NTRS)

    Lucero, John

    2013-01-01

    Since 1995 the Advanced Noise Control Fan (ANCF) has significantly contributed to the advancement of the understanding of the physics of fan tonal noise generation. The 9'x15' WT has successfully tested multiple high speed fan designs over the last several decades. This advanced several tone noise reduction concepts to higher TRL and the validation of fan tone noise prediction codes.

  16. QCSEE fan exhaust bulk absorber treatment evaluation

    NASA Technical Reports Server (NTRS)

    Bloomer, H. E.; Samanich, N. E.

    1980-01-01

    The purpose of the experimental program reported herein was to evaluate the acoustic suppression capability of bulk absorber material designed for use in the fan exhaust duct walls of the QCSEE UTW (under-the-wing) engine and to compare it with other means of acoustic suppression. The paper includes comparison of the acoustic suppression to the original design for the QCSEE UTW engine fan duct which consisted of phased SDOF (single-degree-of-freedom) wall treatment and a splitter and also with the splitter removed. The method of approach consisted of mounting the UTW engine on the test stand of the Lewis Engine Noise Facility with an appropriate array of far-field microphones in order to measure the acoustic levels of the various configurations. Peak suppression was about as predicted with the bulk absorber configuration; however, the broadband characteristics were not attained. Post-test inspection revealed surface oil contamination on the bulk material which could have caused the loss in bandwidth suppression.

  17. Interaction of fan rotor flow with downstream struts

    NASA Technical Reports Server (NTRS)

    Obrien, W. F., Jr.; Reimers, S. L.; Richardson, S. W.

    1983-01-01

    The detailed unsteady pressure field produced on the rotor blades of an axial-flow fan by interaction with downstream struts was investigated. The experimental arrangement was similar to that found in the fan casings of turbofan aircraft engines. Acoustically significant pressure fluctuations were measured on both thy suction and pressure sides of the rotor blades for several positions of the downstream struts. The level of the observed interaction decreased with increased spacing of the struts behind the rotor. An inviscid flow analysis for the disturbance level is compared with trends of the measured results.

  18. 12 Inch Fan Acoustic Research

    NASA Technical Reports Server (NTRS)

    Thomas, R. H.

    1997-01-01

    There were three general purposes of this research; first, to investigate fundamental fan acoustic processes, second, to produce high quality data for the validation of aeroacoustic codes and, third, to investigate candidate noise control concepts. These were all to be investigated using the NASA built and supplied 12 inch fan which is a 0.1 scale model of a modem ultra high bypass fan. NASA also supplied the test environments, wind tunnel entries in the 14 by 22 Foot Subsonic Wind Tunnel and the Anechoic Noise Research Facility. To fulfill the purposes of the grant, investigations were performed in several general topics. In the area of fundamental fan studies, some of the topics involved were azimuthal directivity and tip clearance effects. In the area of high quality validation data significant parameter studies in the wind tunnel tests were performed. And in the area of noise control concepts, heated air injection was studied. The principal investigator performed the work on this grant by leading the concept development, design, planning, data analysis and reporting of the areas studied. The final report for this grant consists of a listing, which follows, of all reports, presentations, and publications that were made for the work done during the performance period.

  19. FAN HOUSE INTERIOR. THREE MOTOR DRIVES FOR POSITIVE DISPLACEMENT BLOWERS ...

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

    FAN HOUSE INTERIOR. THREE MOTOR DRIVES FOR POSITIVE DISPLACEMENT BLOWERS LINE UP ON NORTH WALL. CONCRETE PEDESTALS. CAMERA FACES NORTHEAST. INL NEGATIVE NO. 4291. Unknown Photographer, 2/26/1952 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  20. 14 CFR 29.908 - Cooling fans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... in Category A rotorcraft, it must be shown that a fan blade failure will not prevent continued safe flight either because of damage caused by the failed blade or loss of cooling air. (b) Category B. For... safe landing if a fan blade fails. It must be shown that— (1) The fan blade would be contained in...

  1. 14 CFR 29.908 - Cooling fans.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... in Category A rotorcraft, it must be shown that a fan blade failure will not prevent continued safe flight either because of damage caused by the failed blade or loss of cooling air. (b) Category B. For... safe landing if a fan blade fails. It must be shown that— (1) The fan blade would be contained in...

  2. 14 CFR 29.908 - Cooling fans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... in Category A rotorcraft, it must be shown that a fan blade failure will not prevent continued safe flight either because of damage caused by the failed blade or loss of cooling air. (b) Category B. For... safe landing if a fan blade fails. It must be shown that— (1) The fan blade would be contained in...

  3. 14 CFR 29.908 - Cooling fans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... in Category A rotorcraft, it must be shown that a fan blade failure will not prevent continued safe flight either because of damage caused by the failed blade or loss of cooling air. (b) Category B. For... safe landing if a fan blade fails. It must be shown that— (1) The fan blade would be contained in...

  4. 14 CFR 29.908 - Cooling fans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... in Category A rotorcraft, it must be shown that a fan blade failure will not prevent continued safe flight either because of damage caused by the failed blade or loss of cooling air. (b) Category B. For... safe landing if a fan blade fails. It must be shown that— (1) The fan blade would be contained in...

  5. Acoustic results of supersonic tip speed fan blade modification

    NASA Technical Reports Server (NTRS)

    Jutras, R. R.; Kazin, S. B.

    1974-01-01

    A supersonic tip speed single stage fan was modified with the intent of reducing multiple pure tone (MPT) or buzz saw noise. There were three modifications to the blades from the original design. The modifications to the blade resulted in an increase in cascade throat area causing the shock to start at a lower corrected fan speed. The acoustic results without acoustically absorbing liners showed substantial reduction in multiple pure tone levels. However, an increase in the blade passing frequency noise at takeoff fan speed accompanied the MPT reduction. The net result however, was a reduction in the maximum 1000-foot (304.8 m) altitude level flyover PNL. For the case with acoustic treatment in the inlet outer wall, the takeoff noise increased relative to an acoustically treated baseline. This was largely due to the increased blade passing frequency noise which was not effectively reduced by the liner.

  6. Azimuthal Directivity of Fan Tones Containing Multiple Modes

    NASA Technical Reports Server (NTRS)

    Heidelberg, Laurence J.; Sutliff, Daniel L.; Nallasamy, M.

    1997-01-01

    The directivity of fan tone noise is generally measured and plotted in the sideline or flyover plane and it is assumed that this curve is the same for all azimuthal angles. When two or more circumferential (m-order) modes of the same tone are present in the fan duct, an interference pattern develops in the azimuthal direction both in the duct and in the farfield. In this investigation two m-order modes of similar power were generated in a large low speed fan. Farfield measurements and a finite element propagation code both show substantial variations in the azimuthal direction. Induct mode measurement were made and used as input to the code. Although these tests may represent a worst case scenario, the validity of the current practice of assuming axisymmetry should be questioned.

  7. The Noise of a Forward Swept Fan

    NASA Technical Reports Server (NTRS)

    Dittmar, James H.; Elliott, David M.; Fite, E. Brian

    2003-01-01

    A forward swept fan, designated the Quiet High Speed Fan (QHSF), was tested in the NASA Glenn 9-by 15-foot Low Speed Wind Tunnel to investigate its noise reduction relative to a baseline fan of the same aerodynamic performance. The objective of the Quiet High Speed Fan was a 6 decibel reduction in the Effective Perceived Noise relative to the baseline fan at the takeoff condition. The intent of the Quiet High Speed Fan design was to provide both a multiple pure tone noise reduction from the forward sweep of the fan rotor and a rotor-stator interaction blade passing tone noise reduction from a leaned stator. The tunnel noise data indicted that the Quiet High Speed Fan was quieter than the baseline fan for a significant portion of the operating line and was 6 dB quieter near the takeoff condition. Although reductions in the multiple pure tones were observed, the vast majority of the EPNdB reduction was a result of the reduction in the blade passing tone and its harmonics. The baseline fan's blade passing tone was dominated by the rotor-strut interaction mechanism. The observed blade passing tone reduction could be the result of either the redesign of the Quiet High Speed Fan Rotor or the redesigned stator. The exact cause of this rotor-strut noise reduction, whether from the rotor or stator redesign, was not discernable from this experiment.

  8. Alluvial Fan Delineation from SAR and LIDAR-Derived Digital Elevation Models in the Philippines

    NASA Astrophysics Data System (ADS)

    Aquino, D. T.; Ortiz, I.; Timbas, N.; Gacusan, R.; Montalbo, K.; Eco, R. C.; Lagmay, A.

    2013-12-01

    Occurrence of floods and debris flows leading to the formation of alluvial fans at the base of mountains naturally improve fertility of alluvial plains. However, these formations also have detrimental effects to communities within these zones like the case of Barangay (village) Andap, New Bataan, Compostela Valley where the whole village was wiped out by debris flow when it was hit by Supertyphoon Bopha in 2012. Hence, demarcating the boundaries of alluvial fans is crucial in disaster preparedness and mitigation. This study describes a method to delineate alluvial fans through contour maps from SAR and LiDAR-derived digital elevation models. Based on this data, we used hydrographic apex point polygons to plot the outflow points of upstream watersheds. The watershed and alluvial fan polygons were used to simulate debris flows in the study sites. The fans generated from the flood simulation were consistent with the polygons delineated from the digital elevation model. Satellite imagery and evidences of alluvial deposits found on site revealed 392 alluvial fans in the country. Widest among these is the sprawling 760 sq km fan identified in Cagayan Valley threatening about 434,329 persons at risk of debris flow. Other fans include those identified in Calapan, Mindoro (531 sq km), Kaliwanagan, Pangasinan (436 sq km), Pampanga Alluvial Fan (325 sq km), Mina, Iloilo (315 sq km), Lamsugod, S. Cotabato (286 sq km), in Tignaman, Oton and Alimodian in Iloilo (272 sq km), and the bajada, a series of alluvial fan coalescing to form a larger fan, identified in Ilocos Norte (218 sq km).

  9. Active noise control to reduce the blade tone noise of centrifugal fans

    NASA Astrophysics Data System (ADS)

    Koopmann, G. H.; Neise, W.; Chen, W.

    1988-07-01

    An active noise control method for suppressing the blade tones of centrifugal fans is presented which uses two secondary sound sources mounted into the cutoff region of the fan casing. Experiments were conducted for centrifugal fans with impeller diameters between 280 and 710 mm using two different designs for the secondary sources. The results indicate that the sound field inside the casing is dominated by the rotor locked pressure field, and that the blade tone noise measured in the far-field is generated by the unsteady pressures at the cutoff, which in turn are produced by the flow leaving the impeller.

  10. Performance of two-stage fan having low-aspect-ratio first-stage rotor blading

    NASA Technical Reports Server (NTRS)

    Urasek, D. C.; Gorrell, W. T.; Cunnan, W. S.

    1979-01-01

    The NASA two stage fan was tested with a low aspect ratio first stage rotor having no midspan dampers. At design speed the fan achieved an adiabatic design efficiency of 0.846, and peak efficiencies for the first stage and rotor of 0.870 and 0.906, respectively. Peak efficiency occurred very close to the stall line. In an attempt to improve stall margin, the fan was retested with circumferentially grooved casing treatment and with a series of stator blade resets. Results showed no improvement in stall margin with casing treatment but increased to 8 percent with stator blade reset.

  11. Aerodynamic Design and Computational Analysis of a Spacecraft Cabin Ventilation Fan

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    2010-01-01

    Quieter working environments for astronauts are needed if future long-duration space exploration missions are to be safe and productive. Ventilation and payload cooling fans are known to be dominant sources of noise, with the International Space Station being a good case in point. To address this issue in a cost-effective way, early attention to fan design, selection, and installation has been recommended. Toward that end, NASA has begun to investigate the potential for small-fan noise reduction through improvements in fan aerodynamic design. Using tools and methodologies similar to those employed by the aircraft engine industry, most notably computational fluid dynamics (CFD) codes, the aerodynamic design of a new cabin ventilation fan has been developed, and its aerodynamic performance has been predicted and analyzed. The design, intended to serve as a baseline for future work, is discussed along with selected CFD results

  12. Fan Performance Testing and Oxygen Compatibility Assessment Results for Future Space Suit Life Support Systems

    NASA Technical Reports Server (NTRS)

    Paul, Heather L.; Jennings, Mallory A.; Vogel, Matthew

    2009-01-01

    An advanced portable life support system (PLSS) for the space suit will require a small, robust, and energyefficient system to transport the ventilation gas through the space suit for lunar Extravehicular Activity (EVA) operations. A trade study identified and compared ventilation transport technologies in commercial, military, and space applications to determine which technologies could be adapted for EVA use. Based on the trade study results, five commercially available, 24-volt fans were selected for performance testing at various pressures and flow rates. Measured fan parameters included fan delta-pressures, input voltages, input electrical currents, and in some cases motor windings electrical voltages and currents. In addition, a follow-on trade study was performed to identify oxygen compatibility issues and assess their impact on fan design. This paper outlines the results of the fan performance characterization testing, as well as the results from the oxygen compatibility assessment.

  13. Fan Performance Testing and Oxygen Compatibility Assessment Results for Future Space Suit Life Support Systems

    NASA Technical Reports Server (NTRS)

    Jennings, Mallory A.; Paul, Heather L.; Vogel, Matthew

    2008-01-01

    An advanced portable life support system (PLSS) for the space suit will require a small, robust, and energy-efficient system to transport the ventilation gas through the space suit for lunar Extravehicular Activity (EVA) operations. A trade study identified and compared ventilation transport technologies in commercial, military, and space applications to determine which technologies could be adapted for EVA use. Based on the trade study results, five commercially available, 24volt fans were selected for performance testing at various pressures and flow rates. Measured fan parameters included fan delta-pressures, input voltages, input electrical currents, and in some cases motor windings electrical voltages and currents. In addition, a follow-on trade study was performed to identify oxygen compatibility issues and assess their impact on fan design. This paper outlines the results of the fan performance characterization testing, as well as the results from the oxygen compatibility assessment.

  14. Fan System Optimization Improves Production and Saves Energy at Ash Grove Cement Plant

    SciTech Connect

    2002-05-01

    This case study describes an optimization project implemented on a fan system at Ash Grove Cement Company, which led to annual energy and maintenance savings of $16,000 and 175,000 kilowatt-hours (kWh).

  15. Fan System Optimization Improves Ventilation and Saves Energy at a Computer Chip Manufacturer

    SciTech Connect

    2002-01-01

    This case study describes an optimization project implemented on a fan system at Ash Grove Cement Company, which led to annual energy and maintenance savings of $16,000 and 175,000 kilowatt-hours (kWh).

  16. Heat transfer characteristics for disk fans

    NASA Astrophysics Data System (ADS)

    Prikhodko, Yu. M.; Chekhov, V. P.; Fomichev, V. P.

    2014-08-01

    Multiple-disk fans belong to the class of friction machines; they can be designed in two variants: centrifugal disk fans and diametrical disk fans. Flow patterns in these two types of machines are different, and they possess different heat transfer characteristics. The paper presents results of experimental study for a centrifugal disk fan under atmospheric pressure with air taken as working gas. The radial temperature distribution for a disk was obtained at different rotation speed of the rotor and different heating of the disks. Heat transfer characteristics of a centrifugal disk fan and a diametrical disk fan were compared. The research results demonstrate a higher heat transfer efficiency for centrifugal design versus diametrical disk design.

  17. Laboratory alluvial fans in one dimension.

    PubMed

    Guerit, L; Métivier, F; Devauchelle, O; Lajeunesse, E; Barrier, L

    2014-08-01

    When they reach a flat plain, rivers often deposit their sediment load into a cone-shaped structure called alluvial fan. We present a simplified experimental setup that reproduces, in one dimension, basic features of alluvial fans. A mixture of water and glycerol transports and deposits glass beads between two transparent panels separated by a narrow gap. As the beads, which mimic natural sediments, get deposited in this gap, they form an almost one-dimensional fan. At a moderate sediment discharge, the fan grows quasistatically and maintains its slope just above the threshold for sediment transport. The water discharge determines this critical slope. At leading order, the sediment discharge only controls the velocity at which the fan grows. A more detailed analysis reveals a slight curvature of the fan profile, which relates directly to the rate at which sediments are transported. PMID:25215729

  18. Lift/cruise fan V/STOL technology aircraft design definition study. Volume 2: Propulsion transmission system design

    NASA Technical Reports Server (NTRS)

    Obrien, W. J.

    1976-01-01

    Two types of lift/cruise fan technology aircraft were conceptually designed. One aircraft used turbotip fans pneumatically interconnected to three gas generators, and the other aircraft used variable pitch fans mechanically interconnected to three turboshaft engines. The components of each propulsion transmission system were analyzed and designed to the depth necessary to determine areas of risk, development methods, performance, weights and costs. The types of materials and manufacturing processes were identified to show that the designs followed a low cost approach. The lift/cruise fan thrust vectoring hoods, which are applicable to either aircraft configuration, were also evaluated to assure a low cost/low risk approach.

  19. Fan Noise Source Diagnostic Test Computation of Rotor Wake Turbulence Noise

    NASA Technical Reports Server (NTRS)

    Nallasamy, M.; Envia, E.; Thorp, S. A.; Shabbir, A.

    2002-01-01

    An important source mechanism of fan broadband noise is the interaction of rotor wake turbulence with the fan outlet guide vanes. A broadband noise model that utilizes computed rotor flow turbulence from a RANS code is used to predict fan broadband noise spectra. The noise model is employed to examine the broadband noise characteristics of the 22-inch Source Diagnostic Test fan rig for which broadband noise data were obtained in wind tunnel tests at the NASA Glenn Research Center. A 9-case matrix of three outlet guide vane configurations at three representative fan tip speeds are considered. For all cases inlet and exhaust acoustic power spectra are computed and compared with the measured spectra where possible. In general, the acoustic power levels and shape of the predicted spectra are in good agreement with the measured data. The predicted spectra show the experimentally observed trends with fan tip speed, vane count, and vane sweep. The results also demonstrate the validity of using CFD-based turbulence information for fan broadband noise calculations.

  20. Channel Networks on Large Fans: Refining Analogs for the Ridge-forming Unit, Sinus Meridiani

    NASA Technical Reports Server (NTRS)

    Wilkinson, Justin

    2009-01-01

    Stream channels are generally thought of as forming within confined valley settings, separated by interfluves. Sinuous ridges on Mars and Earth are often interpreted as stream channels inverted by subsequent erosion of valley sides. In the case of the ridge-forming unit (RFU), this interpretation fails to explain the (i) close spacing of the ridges, which are (ii) organized in networks, and which (iii) cover large areas (approximately 175,000 km (exp 2)). Channel networks on terrestrial fans develop unconfined by valley slopes. Large fans (100s km long) are low-angle, fluvial features, documented worldwide, with characteristics that address these aspects of the RFU. Ridge patterns Channels on large fans provide an analog for the sinuous and elongated morphology of RFU ridges, but more especially for other patterns such as subparallel, branching and crossing networks. Branches are related to splays (delta-like distributaries are rare), whose channels can rejoin the main channel. Crossing patterns can be caused by even slight sinuosity splay-related side channels often intersect. An avulsion node distant from the fan apex, gives rise to channels with slightly different, and hence intersecting, orientations. Channels on neighboring fans intersect along the common fan margin. 2. Network density Channels are the dominant feature on large terrestrial fans (lakes and dune fields are minor). Inverted landscapes on subsequently eroded fans thus display indurated channels as networks of significantly close-spaced ridges. 3. Channel networks covering large areas Areas of individual large terrestrial fans can reach >200,000 km 2 (105-6 km 2 with nested fans), providing an analog for the wide area distribution of the RFU.

  1. Enhanced Fan Noise Modeling for Turbofan Engines

    NASA Technical Reports Server (NTRS)

    Krejsa, Eugene A.; Stone, James R.

    2014-01-01

    This report describes work by consultants to Diversitech Inc. for the NASA Glenn Research Center (GRC) to revise the fan noise prediction procedure based on fan noise data obtained in the 9- by 15 Foot Low-Speed Wind Tunnel at GRC. The purpose of this task is to begin development of an enhanced, analytical, more physics-based, fan noise prediction method applicable to commercial turbofan propulsion systems. The method is to be suitable for programming into a computational model for eventual incorporation into NASA's current aircraft system noise prediction computer codes. The scope of this task is in alignment with the mission of the Propulsion 21 research effort conducted by the coalition of NASA, state government, industry, and academia to develop aeropropulsion technologies. A model for fan noise prediction was developed based on measured noise levels for the R4 rotor with several outlet guide vane variations and three fan exhaust areas. The model predicts the complete fan noise spectrum, including broadband noise, tones, and for supersonic tip speeds, combination tones. Both spectra and directivity are predicted. Good agreement with data was achieved for all fan geometries. Comparisons with data from a second fan, the ADP fan, also showed good agreement.

  2. The lift-fan aircraft: Lessons learned

    NASA Technical Reports Server (NTRS)

    Deckert, Wallace H.

    1995-01-01

    This report summarizes the highlights and results of a workshop held at NASA Ames Research Center in October 1992. The objective of the workshop was a thorough review of the lessons learned from past research on lift fans, and lift-fan aircraft, models, designs, and components. The scope included conceptual design studies, wind tunnel investigations, propulsion systems components, piloted simulation, flight of aircraft such as the SV-5A and SV-5B and a recent lift-fan aircraft development project. The report includes a brief summary of five technical presentations that addressed the subject The Lift-Fan Aircraft: Lessons Learned.

  3. Turbulent dispersion via fan-generated flows

    PubMed Central

    Halloran, Siobhan K.; Wexler, Anthony S.; Ristenpart, William D.

    2014-01-01

    Turbulent dispersion of passive scalar quantities has been extensively studied in wind tunnel settings, where the flow is carefully conditioned using flow straighteners and grids. Much less is known about turbulent dispersion in the “unconditioned” flows generated by fans that are ubiquitous in indoor environments, despite the importance of these flows to pathogen and contaminant transport. Here, we demonstrate that a point source of scalars released into an airflow generated by an axial fan yields a plume whose width is invariant with respect to the fan speed. The results point toward a useful simplification in modeling of disease and pollution spread via fan-generated flows. PMID:24932096

  4. Noise suppression by flexible fan silencers

    SciTech Connect

    Partyka, J.; Kelly, T.R.J.

    1995-12-31

    This paper presents the results on noise testing of a fan only, as well as the results of a steel silencer and of flexible silencers that were connected directly to a fan. On-site facilities and free-field method set by the British Standards Institution were used to measure and then compare the fan only and different practical silencer configuration setups. In order to determine the fan-silencer combination that would give the maximum noise attenuation, total noise intensity, noise contributed to by the fan motor only, as well as aerodynamical noise created through air interacting with the fan parts were considered to obtain decibel readings for the octave bands. Subsequently, the optimal configuration found was the setup with flexible silencers on the fan inlet and the fan outlet. If only one silencer is used, it should be installed on the fan inlet. The aerodynamic noise affects the low frequencies. The flow noise is then overtaken at 1 kHz by the mechanical noise.

  5. Factors controlling ebro deep-sea fan growth, Mediterranean Sea

    SciTech Connect

    Nelson, C.H.; Maldonado, A.; Alonso, B.; Palanques, A.; Ryan, W.B.F.; Kastens, K.; O'Connel, S.

    1985-01-01

    Tectonic, sediment-source and sea-level factors control depositional patterns of the Ebro deep-sea fan system. In unstable, steep continental slope terrain, mass movement of material results in wide gullied canyons and formation of non-channelized debris aprons. These fan channels develop low sinuosity and generally traverse the continental rise without feeding into depositional lobes because of steep gradients (1:50 to 1:100) and sediment draining into the subsiding Valencia Valley graben. An abundance of sediment input points from mass failure and many river-fed canyons contributes to a depositional pattern of side-by-side debris aprons and separate channel-levee complexes. When a large sediment supply feeds a channel for a relatively long period 1) fan valley sinuosity increases: 2) channel walls are modified through undercutting, slumping, and crevasse splays: 3) channel bifurcation occurs: 4) incipient depositional lobe formation begins. Lowering of sea levels in Late Pleistocene time permitted the access of coarse river sediment to slope valleys and promoted deposition of numerous turbidites and active growth of the fan. During the Holocene, when sea levels have been high, a regime of hemipelagic sedimentation, mass movement, and debris apron sedimentation has dominated.

  6. The Forming of AISI 409 sheets for fan blade manufacturing

    SciTech Connect

    Foroni, F. D.; Menezes, M. A.; Moreira Filho, L. A.

    2007-04-07

    The necessity of adapting the standardized fan models to conditions of higher temperature has emerged due to the growth of concern referring to the consequences of the gas expelling after the Mont Blanc tunnel accident in Italy and France, where even though, with 100 fans in operation, 41 people died. The objective of this work is to present an alternative to the market standard fans considering a new technology in constructing blades. This new technology introduces the use of the stainless steel AISI 409 due to its good to temperatures of gas exhaust from tunnels in fire situation. The innovation is centered in the process of a deep drawing of metallic sheets in order to keep the ideal aerodynamic superficies for the fan ideal performance. Through the impression of circles on the sheet plane it is shown, experimentally, that, during the pressing process, the more deformed regions on the sheet plane of the blade can not reach the deformation limits of the utilized sheet material.

  7. Active control of fan noise from a turbofan engine

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H.; Burdisso, Ricardo A.; Fuller, Christopher R.; O'Brien, Walter F.

    1993-01-01

    A three channel active control system is applied to an operational turbofan engine in order to reduce tonal noise produced by both the fan and high pressure compressor. The control approach is the feedforward filtered-x least-mean-square algorithm implemented on a digital signal processing board. Reference transducers mounted on the engine case provides blade passing and harmonics frequency information to the controller. Error information is provided by large area microphones placed in the acoustic far field. In order to minimize the error signal, the controller actuates loudspeakers mounted on the inlet to produce destructive interference. The sound pressure level of the fundamental tone of the fan was reduced using the three channel controller by up to 16 dB over a 60 deg angle about the engine axis. A single channel controller could produce reduction over a 30 deg angle. The experimental results show the control to be robust. Simultaneous control of two tones is done with parallel controllers. The fundamental and the first harmonic tones of the fan were controlled simultaneously with reductions of 12 dBA and 5 dBA, respectively, measured on the engine axis. Simultaneous control was also demonstrated for the fan fundamental and the high pressure compressor fundamental tones.

  8. Active control of fan noise from a turbofan engine

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H.; Burdisso, Ricardo A.; Fuller, Christopher R.; O'Brien, Walter F.

    1994-01-01

    A three-channel active control system is applied to an operational turbofan engine to reduce tonal noise produced by both the fan and the high-pressure compressor. The control approach is the feedforward filtered-x least-mean-square algorithm implemented on a digital signal processing board. Reference transducers mounted on the engine case provide blade passing and harmonics frequency information to the controller. Error information is provided by large area microphones placed in the acoustic far field. To minimize the error signal, the controller actuates loudspeakers mounted on the inlet to produce destructive interference. The sound pressure level of the fundamental tone of the fan was reduced using the three-channel controller by up to 16 dB over a +/- 30-deg angle about the engine axis. A single-channel controller could produce reduction over a +/- 15-deg angle. The experimental results show the control to be robust. Outside of the areas contolled, the levels of the tone actually increased due to the generation of radial modes by the control sources. Simultaneous control of two tones is achieved with parallel controllers. The fundamental and the first harmonic tones of the fan were controlled simultaneously with reductions of 12 and 5 dBA, respectively, measured on the engine axis. Simultaneous control was also demonstrated for the fan fundamental and the high-pressure compressor fundamental tones.

  9. Composite Fan Blade Design for Advanced Engine Concepts

    NASA Technical Reports Server (NTRS)

    Abumeri, Galib H.; Kuguoglu, Latife H.; Chamis, Christos C.

    2004-01-01

    The aerodynamic and structural viability of composite fan blades of the revolutionary Exo-Skeletal engine are assessed for an advanced subsonic mission using the NASA EST/BEST computational simulation system. The Exo-Skeletal Engine (ESE) calls for the elimination of the shafts and disks completely from the engine center and the attachment of the rotor blades in spanwise compression to a rotating casing. The fan rotor overall adiabatic efficiency obtained from aerodynamic analysis is estimated at 91.6 percent. The flow is supersonic near the blade leading edge but quickly transitions into a subsonic flow without any turbulent boundary layer separation on the blade. The structural evaluation of the composite fan blade indicates that the blade would buckle at a rotor speed that is 3.5 times the design speed of 2000 rpm. The progressive damage analysis of the composite fan blade shows that ply damage is initiated at a speed of 4870 rpm while blade fracture takes place at 7640 rpm. This paper describes and discusses the results for the composite blade that are obtained from aerodynamic, displacement, stress, buckling, modal, and progressive damage analyses. It will be demonstrated that a computational simulation capability is readily available to evaluate new and revolutionary technology such as the ESE.

  10. Analysis and control of computer cooling fan noise

    NASA Astrophysics Data System (ADS)

    Wong, Kam

    This thesis is divided into three parts: the study of the source mechanisms and their separation, passive noise control, and active noise control. The mechanisms of noise radiated by a typical computer cooling fan is investigated both theoretically and experimentally focusing on the dominant rotor-stator interaction. The unsteady force generated by the aerodynamic interaction between the rotor blades and struts is phase locked with the blade rotation and radiates tonal noise. Experimentally, synchronous averaging with the rotation signal extracts the tones made by the deterministic part of the rotor-strut interaction mechanism. This averaged signal is called the rotary noise. The difference between the overall noise and rotary noise is defined as random noise which is broadband in the spectrum. The deterministic tonal peaks are certainly more annoying than the broadband, so the suppression of the tones is the focus of this study. Based on the theoretical study of point force formulation, methods are devised to separate the noise radiated by the two components of drag and thrust forces on blades and struts. The source separation is also extended to the leading and higher order modes of the spinning pressure pattern. By using the original fan rotor and installing it in various casings, the noise sources of the original fan are decomposed into elementary sources through directivity measurements. Details of the acoustical directivity for the original fan and its various modifications are interpreted. For the sample fan, two common features account for most of the tonal noise radiated. The two features are the inlet flow distortion caused by the square fan casing, and the large strut carrying the electric wires for the motor. When the inlet bellmouth is installed and the large strut is trimmed down to size, a significant reduction of 12 dB in tonal sound power is achieved. These structural corrections constitute the passive noise control. However, the end product still

  11. A comparative study of varying fan noise mitigation techniques in relation to sustainable design goals

    NASA Astrophysics Data System (ADS)

    Overweg, Cornelis; Fullerton, Jeff L.

    2005-04-01

    Green building design promotes effective use of materials and energy, improved indoor environmental quality (IEQ), and enhanced occupant comfort. These ``green'' goals can occasionally conflict with common acoustical approaches used for fan noise control. A design striving for low noise levels from the ventilation system to benefit occupant comfort can inadvertently introduce elements that are contradictory to other green building objectives. For example, typical fan noise control devices introduce higher energy consumption or less beneficial indoor environmental quality. This paper discusses the acoustical, mechanical, environmental, and relative cost impacts of various fan noise control techniques.

  12. Experimental Evaluation of Installed Cooking Exhaust Fan Performance

    SciTech Connect

    Singer, Brett C.; Delp, William W.; Apte, Michael G.

    2010-11-01

    The installed performance of cooking exhaust fans was evaluated through residential field experiments conducted on a sample of 15 devices varying in design and other characteristics. The sample included two rear downdraft systems, two under-cabinet microwave over range (MOR) units, three different installations of an under-cabinet model with grease screens across the bottom and no capture hood, two devices with grease screens covering the bottom of a large capture hood (one under-cabinet, one wall-mount chimney), four under-cabinet open hoods, and two open hoods with chimney mounts over islands. Performance assessment included measurement of airflow and sound levels across fan settings and experiments to quantify the contemporaneous capture efficiency for the exhaust generated by natural gas cooking burners.Capture efficiency is defined as the fraction of generated pollutants that are removed through the exhaust and thus not available for inhalation of household occupants. Capture efficiency (CE) was assessed for various configurations of burner use (e.g., single front, single back, combination of one front and one back, oven) and fan speed setting. Measured airflow rates were substantially lower than the levels noted in product literature for many of the units. This shortfall was observed for several units costing in excess of $1000. Capture efficiency varied widely (from<5percent to roughly 100percent) across devices and across conditions for some devices. As expected, higher capture efficiencies were achieved with higher fan settings and the associated higher air flow rates. In most cases, capture efficiencies were substantially higher for rear burners than for front burners. The best and most consistent performance was observed for open hoods that covered all cooktop burners and operated at higher airflow rates. The lowest capture efficiencies were measured when a front burner was used with a rear backdraft system or with lowest fan setting for above the range

  13. Thermophysical Characterization of Terrestrial Alluvial Fans, With Applications to Mars

    NASA Astrophysics Data System (ADS)

    Moersch, J. E.; Whisner, S. C.; Hardgrove, C.

    2005-12-01

    Visible and infrared spectral remote sensing are currently being used to map lithologic variation on Mars, but these techniques are only sensitive to a depth equivalent to a few times the wavelength of observation (several 10's of microns at most). Thus, a fine regolith can make it difficult to characterize the geology of a surface based on spectral properties. This problem can be partially ameliorated by using thermal infrared temperature images. The temperature of the surface is controlled by material within approximately one diurnal thermal skin depth (typically a few cm) of the surface. Thermal images "see below" thin, spectrally obscuring surface layers, and enable the mapping of some underlying geologic heterogeneities (but not mineral compositions). Temperature variation is related, in part, to differences in thermal inertia, which in turn are related to lithology, particle size, degree of induration, and (for Earth) moisture content. THEMIS (and other) images of the Martian surface reveal a variety of features that may be the result of sedimentary processes. Earth analogs have been proposed for many of these features, but very little terrestrial analog work has been done to establish whether particular classes of sedimentary features have distinctive spatial-thermophysical signatures. Sedimentary processes often lead to sorting of grain sizes and/or varying degrees of cementation, so it is reasonable to expect that such signatures might exist. Here we present the results of a preliminary study of alluvial fans in Death Valley. As seen from above in ASTER nighttime thermal infrared images, these fans display distinct "thermophysical facies." Each fan apex has a relatively high thermal inertia, mid-fan areas have intermediate thermal inertias, and distal terminus areas have relatively low thermal inertias. This pattern of thermal inertias is consistent with field-based grain size studies that have been conducted on other debris flow-dominated fans in the area

  14. Miocene Blanca Fan, Northern Channel Islands, California: Small fans reflecting tectonism and volcanism

    USGS Publications Warehouse

    McLean, H.; Howell, D.G.

    1984-01-01

    Blanca fan is a submarine fan composed of Miocene volcaniclastic strata. Parts of the fan system are exposed on Santa Cruz and Santa Rosa Islands, and possibly correlative strata crop out on San Miguel and Santa Catalina Islands. The Blanca fan and underlying breccia reflect regional transcurrent faulting in the California Continental Borderland and development of a system of rapidly subsiding basins and uplifted linear ridges during early and middle Miocene time. Erosion of uplifted crystalline basement rocks followed by the onset of silicic volcanism created linear sediment sources for the alluvial and submarine fans, respectively. ?? 1984 Springer-Verlag New York Inc.

  15. Streaming Scholarship: Using Fan Vids to Teach "Harry Potter"

    ERIC Educational Resources Information Center

    Winters, Sarah Fiona

    2013-01-01

    This article argues that Harry Potter fan vids can be used in the classroom as works of secondary criticism about J. K. Rowling's primary text. It makes two claims: the first is that vids can be read as criticism of a particular text (in this case Harry Potter) alongside other critical essays on that text; the second is that the practice of…

  16. Metal spar/superhybrid shell composite fan blades. [for application to turbofan engins

    NASA Technical Reports Server (NTRS)

    Salemme, C. T.; Murphy, G. C.

    1979-01-01

    The use of superhybrid materials in the manufacture and testing of large fan blades is analyzed. The FOD resistance of large metal spar/superhybrid fan blades is investigated. The technical effort reported was comprised of: (1) preliminary blade design; (2) detailed analysis of two selected superhybrid blade designs; (3) manufacture of two process evaluation blades and destructive evaluation; and (4) manufacture and whirligig testing of six prototype superhybrid blades.

  17. Fiber composite fan blade impact improvement program

    NASA Technical Reports Server (NTRS)

    Oller, T. L.

    1976-01-01

    The results of a 20-month program, designed to investigate parameters which effect the foreign object damage resulting from ingestion of birds into fan blades are described. Work performed on this program included the design, fabrication, and impact testing of QCSEE fan blades to demonstrate improvement in resistance relative to existing blades and also the design and demonstration of a pin root attachment concept.

  18. Radon reduction using sub floor fans

    SciTech Connect

    Harley, N.H.; Chittaporn, P.

    1996-06-01

    The basement and second floor {sup 222}Rn concentrations in an energy efficient home were measured hourly for 6 y using continuous monitors of our design. The home had a subslab pipe network installed during construction, and for the past 2 y a 150 cfm fan was operative venting air via ductwork inside the chimney exiting on the roof. During this measurement interval, experiments were conducted with the fan in 3 modes: (1) with the subslab fan off, (2) in the conventional direction auctioning air from beneath the slab to outside, and (3) reversed, blowing outdoor air into the network under the slab. We have a large data base to show that the indoor {sup 222}R n concentration varies inversely with the indoor/outdoor temperature difference. In order to compare the 3 fan modes directly, we selected 50 to 90 d periods when the outdoor temperature was essentially the same. For the 3 modes, the fan off, blowing upward, and blowing downward, the basement concentration averaged 80, 38, and 34 Bq m{sup -3}, respectively. Radon peaks or surges occur over a period of about 1 d during falling barometric pressure. With the fan blowing downward, these {sup 222}Rn peaks tend to be smaller but only marginally so. We conclude that in this home the reduction in {sup 222}Rn with the fan and subslab pipe network operating was essentially the same regardless of the direction of flow from the fan.

  19. Modeling and Prediction of Fan Noise

    NASA Technical Reports Server (NTRS)

    Envia, Ed

    2008-01-01

    Fan noise is a significant contributor to the total noise signature of a modern high bypass ratio aircraft engine and with the advent of ultra high bypass ratio engines like the geared turbofan, it is likely to remain so in the future. As such, accurate modeling and prediction of the basic characteristics of fan noise are necessary ingredients in designing quieter aircraft engines in order to ensure compliance with ever more stringent aviation noise regulations. In this paper, results from a comprehensive study aimed at establishing the utility of current tools for modeling and predicting fan noise will be summarized. It should be emphasized that these tools exemplify present state of the practice and embody what is currently used at NASA and Industry for predicting fan noise. The ability of these tools to model and predict fan noise is assessed against a set of benchmark fan noise databases obtained for a range of representative fan cycles and operating conditions. Detailed comparisons between the predicted and measured narrowband spectral and directivity characteristics of fan nose will be presented in the full paper. General conclusions regarding the utility of current tools and recommendations for future improvements will also be given.

  20. 10 CFR 429.32 - Ceiling fans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Ceiling fans. 429.32 Section 429.32 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR CONSUMER PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.32 Ceiling fans. (a) Sampling plan for selection...

  1. 10 CFR 429.32 - Ceiling fans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Ceiling fans. 429.32 Section 429.32 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR CONSUMER PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.32 Ceiling fans. (a) Sampling plan for selection...

  2. 10 CFR 429.32 - Ceiling fans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Ceiling fans. 429.32 Section 429.32 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR CONSUMER PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.32 Ceiling fans. (a) Sampling plan for selection...

  3. FAN DOOR TESTING ON CRAWL SPACE BUILDINGS

    EPA Science Inventory

    The paper discusses: (1) fan door testing of crawl spaces in nine buildings in Tennessee, and (2) using two fan doors to estimate the leakage area of the floor between the crawl space and the living space. The testing gives some insight into the tightness of crawlspaces and the l...

  4. The Right to Be a Fan

    ERIC Educational Resources Information Center

    Gutierrez, Peter

    2011-01-01

    Reading experts have consistently cited the importance of independent reading, reading for pleasure, and fostering "a love of reading." Unfortunately, fanning the fire of fan readership is not so easy in the service of our clear-cut and standards-aligned curricula, except perhaps in small, carefully channeled doses. Moreover, the impetus for such…

  5. Fan type end moraine related glaciofluvial deposits of Last Glaciation from Lithuania

    NASA Astrophysics Data System (ADS)

    Šinkūnė, Eglė; Šinkūnas, Petras

    2015-04-01

    Several alluvial-fan type end moraine related sites were chosen for detailed sedimentological analyses in ice marginal zone of the last glaciation in Lithuania. Such glaciofluvial ice-marginal fans are formed close to linear ice-sheet front and have semi-conical form or represent simple asymmetric hill forms or more complex ridges with steep proximal and gentler distal slopes. Sedimentary sequences of ice-marginal fans studied consist mainly of waterlain sandy and gravelly deposits with pebbles and boulders. In some sequences a debris-flow deposits are observed as well as beds of sorted material interbedded with dominating high energy sheetflow deposits. Sediment grain size, sorting, structure and bedding characteristics dependent on ice proximity and hydrodynamic conditions were analysed. Highly pulsatory water discharge can be interpreted from depositional architecture of the end moraine related fans. The inferred character of sedimentation suggests that landforms consisting of deposits studied are genetically similar to the alluvial fans. According to the sedimentation features the investigated landforms are an intermediate between the marginal glaciofluvial ridges and sandur fans. Are they a transition zone of sedimentation between the end moraines and proximal outwash plains, or can be the end moraine related fans distinguished as a separate type of glaciofluvial deposits? This question is still open.

  6. Alluvial fan response to climatic change: Insights from numerical modeling (Invited)

    NASA Astrophysics Data System (ADS)

    Pelletier, J. D.

    2009-12-01

    Alluvial fans in the western U.S. exhibit a regionally correlative sequence of Plio-Quaternary deposits. Cosmogenic and U-series dating has greatly improved the age control on these deposits and their associated terraces and generally strengthened the case for aggradation during humid-to-arid transitions. Still, the linkages between climate change, upland basin response, and alluvial fan response are not well constrained. Fans may fill and cut as a result of autogenetic processes/internal adjustments, changes in regional temperature (which controls snowmelt-induced flooding), changes in the frequency-size distribution of rainfall events, and/or changes in upslope vegetation. Here I describe the results of a numerical modeling study designed to better constrain the relationships between different end-member forcing mechanisms and the geologic record of alluvial fan deposits and terraces. The model solves the evolution of the fan topography using Exner's equation (conservation of mass) coupled with a nonlinear, threshold-controlled transport relation for sand and gravel. Bank retreat is modeled using an advection equation with a rate proportional to bank shear stress. I begin by considering the building of a fan under conditions of constant water and sediment supply. This simple system exhibits all of the complexity of fans developed under experimental conditions, and it provides insights into the mechanisms that control avulsions and it provides a baseline estimate for the within-fan relief that can result from autogenetic processes. Relationships between the magnitude and period of variations in the sediment-to-water ratio and the geomorphic response of fans are then discussed. I also consider the response of a coupled drainage basin-fan system to changes in climate, including the hydrologic and vegetation response of upland hillslopes. Fans can aggrade or incise in response to the same climatic event depending on the relief of the upstream drainage basin, which

  7. Flood hazard assessment on alluvial fans: an examination of the methodology

    SciTech Connect

    French, R.H.

    1984-08-01

    The report presents the results of a critical examination of assumptions and methodology recommended by the Federal Emergency Management Agency (FEMA) to assess flood hazard on alluvial fans. The conculsions reached are as follows. First, the assumption that a flow on an alluvial fan has an equal probability of crossing any point on a given contour seems to be a very conservative assumption. Second, given the data from the Nevada Test Site, it would appear that the assumption that fans have critical to supercritical slopes is acceptable. Third, the present methods of estimating channel width and depth on alluvial fans seem to be invalid. Fourth, the specific flood hazard evaluation procedures recommended by FEMA are not valid in some cases because they are based on the assumption that sufficient records exist to do a standard peak flow analysis. Fifth, the validity of the implied assumption that debris flows present no risk can only be assessed after a location on a fan relative to the intersection point has been established. It is concluded that the current methods of flood hazard assessment on alluvial fans are not adequate given the current and projected economic value of structures and development on alluvial fans in the southwestern United States. 55 references, 5 figures, 5 tables.

  8. Fan-fold shielded electrical leads

    DOEpatents

    Rohatgi, Rajeev R.; Cowan, Thomas E.

    1996-01-01

    Fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate.

  9. Advanced Noise Control Fan Aerodynamic Performance

    NASA Technical Reports Server (NTRS)

    Bozak, Richard F., Jr.

    2009-01-01

    The Advanced Noise Control Fan at the NASA Glenn Research Center is used to experimentally analyze fan generated acoustics. In order to determine how a proposed noise reduction concept affects fan performance, flow measurements can be used to compute mass flow. Since tedious flow mapping is required to obtain an accurate mass flow, an equation was developed to correlate the mass flow to inlet lip wall static pressure measurements. Once this correlation is obtained, the mass flow for future configurations can be obtained from the nonintrusive wall static pressures. Once the mass flow is known, the thrust and fan performance can be evaluated. This correlation enables fan acoustics and performance to be obtained simultaneously without disturbing the flow.

  10. Supersonic through-flow fan assessment

    NASA Technical Reports Server (NTRS)

    Kepler, C. E.; Champagne, G. A.

    1988-01-01

    A study was conducted to assess the performance potential of a supersonic through-flow fan engine for supersonic cruise aircraft. It included a mean-line analysis of fans designed to operate with in-flow velocities ranging from subsonic to high supersonic speeds. The fan performance generated was used to estimate the performance of supersonic fan engines designed for four applications: a Mach 2.3 supersonic transport, a Mach 2.5 fighter, a Mach 3.5 cruise missile, and a Mach 5.0 cruise vehicle. For each application an engine was conceptualized, fan performance and engine performance calculated, weight estimates made, engine installed in a hypothetical vehicle, and mission analysis was conducted.

  11. Blade Vibration Measurement System for Unducted Fans

    NASA Technical Reports Server (NTRS)

    Marscher, William

    2014-01-01

    With propulsion research programs focused on new levels of efficiency and noise reduction, two avenues for advanced gas turbine technology are emerging: the geared turbofan and ultrahigh bypass ratio fan engines. Both of these candidates are being pursued as collaborative research projects between NASA and the engine manufacturers. The high bypass concept from GE Aviation is an unducted fan that features a bypass ratio of over 30 along with the accompanying benefits in fuel efficiency. This project improved the test and measurement capabilities of the unducted fan blade dynamic response. In the course of this project, Mechanical Solutions, Inc. (MSI) collaborated with GE Aviation to (1) define the requirements for fan blade measurements; (2) leverage MSI's radar-based system for compressor and turbine blade monitoring; and (3) develop, validate, and deliver a noncontacting blade vibration measurement system for unducted fans.

  12. Experimental Study of Alluvial Fan Formation

    NASA Astrophysics Data System (ADS)

    Delorme, P.; Devauchelle, O.; Barrier, L.; Métivier, F.

    2015-12-01

    At the outlet of mountain ranges, rivers flow onto flatter lowlands. The associated change of slope causes sediment deposition. As the river is free to move laterally, it builds conical sedimentary structures called alluvial fans. Their location at the interface between erosional and depositional areas makes them valuable sedimentary archives. To decipher these sedimentary records, we need to understand the dynamics of their growth. Most natural fans are built by braided streams. However, to avoid the complexity of braided rivers, we develop a small-scale experiment in which an alluvial fan is formed by a single channel. We use a mixture of water and glycerol to produce a laminar river. The fluid is mixed with corindon sand (~ 300 μm) in a tilted channel and left free to form a fan around its outlet. The sediment and water discharges are constant during an experimental run. We record the fan progradation and the channel morphology with top-view pictures. We also generate an elevation map with an optical method based on the deformation of a moiré pattern. We observe that, to leading order, the fan remains self-affine as it grows, with a constant slope. We compare two recent studies about the formation of one-dimensionnal fan [Guerit et al. 2014] and threshold rivers [Seizilles et al. 2013] to our experimental findings. In particular, we propose a theory witch relates the fan morphology to the control parameters ( fluid and sediment discharges, grain size). Our observation accord with the predictions, suggesting that the fan is built near the threshold of sediment motion. Finally, we intend to expand our interpretation to alluvial fans build by single-thread channels ( Okavango, Bostwana; Taquari and Paraguay, Brasil; Pastaza, Peru).

  13. Geophysical Investigation of Subsurface Characteristics of Icy Debris Fans with Ground Penetrating Radar in the Wrangell Mountains, Alaska

    NASA Astrophysics Data System (ADS)

    Sun, L. F.; Pun, W.; Milkereit, B.

    2011-12-01

    surveys provided the GPR signal velocity through the subsurface material and allowed transformation of two-way traveltimes (TWTT) in GPR profiles to be converted to depth. In addition, the eight WARR surveys spaced on the fans and on the glacier provide information on variability of subsurface velocities. The profiles of the Middle and West fan have more energy returning to the surface and therefore many more reflections than profiles done on the McCarthy Glacier. Based on the WARR surveys, we interpret the lower energy return in the glacier to be caused by two reasons. 1) The increased attenuation due to wet ice versus drier ice and on the fan with GPR velocities >0.15m/ns. 2) Lack of interfaces in the glacier compared to those in the fans which are produced by the events depositing material to an ablated icy debris fan surface. The GPR profiles on the West and Middle fans show multiple point scatters at TWTT of less than 200ns. The Middle fan is distinguished from the West fan by its multiple point scatters at TWTT greater than 200ns, clearly showing the Middle fan with a greater thickness. The observations from the GPR profiles correlate with the photographic evidence for types of processes and the composition of their deposits on each fan respectively.

  14. Geophysical Investigation of Subsurface Characteristics of Icy Debris Fans with Ground Penetrating Radar in the Wrangell Mountains, Alaska

    NASA Astrophysics Data System (ADS)

    Smith, T. D.; Jacob, R. W.

    2013-12-01

    surveys provided the GPR signal velocity through the subsurface material and allowed transformation of two-way traveltimes (TWTT) in GPR profiles to be converted to depth. In addition, the eight WARR surveys spaced on the fans and on the glacier provide information on variability of subsurface velocities. The profiles of the Middle and West fan have more energy returning to the surface and therefore many more reflections than profiles done on the McCarthy Glacier. Based on the WARR surveys, we interpret the lower energy return in the glacier to be caused by two reasons. 1) The increased attenuation due to wet ice versus drier ice and on the fan with GPR velocities >0.15m/ns. 2) Lack of interfaces in the glacier compared to those in the fans which are produced by the events depositing material to an ablated icy debris fan surface. The GPR profiles on the West and Middle fans show multiple point scatters at TWTT of less than 200ns. The Middle fan is distinguished from the West fan by its multiple point scatters at TWTT greater than 200ns, clearly showing the Middle fan with a greater thickness. The observations from the GPR profiles correlate with the photographic evidence for types of processes and the composition of their deposits on each fan respectively.

  15. Compressor and fan wake characteristics

    NASA Technical Reports Server (NTRS)

    Lakshminarayana, B.

    1975-01-01

    Approaches for developing an analytical model capable of determining the effects of rotor flow and blade parameters and turbulence properties (i.e. energy, velocity correlations, and length scale) on the rotor wake characteristics and its diffusion properties are discussed. The three-dimensional model will employ experimental measurements, instantaneous velocities, and turbulence properties at various stations downstream from a rotor. A triaxial probe and a rotating conventional probe, which is mounted on a traverse gear operated by two step motors, are to be used for these measurements. The final rotor wake model will be capable of predicting the discrete and broadband noise generated in a fan rotor and of evaluating the aerodynamic losses, efficiency and optimum spacing between a rotor and stator in turbomachinery.

  16. Compressor and fan wake characteristics

    NASA Technical Reports Server (NTRS)

    Reynolds, B.; Hah, C.; Lakshminarayana, B.; Ravindranath, A.

    1978-01-01

    A triaxial probe and a rotating conventional probe, mounted on a traverse gear operated by two step motors were used to measure the mean velocities and turbulence quantities across a rotor wake at various radial locations and downstream stations. The data obtained was used in an analytical model developed to study how rotor flow and blade parameters and turbulence properties such as energy, velocity correlations, and length scale affect the rotor wake characteristics and its diffusion properties. The model, includes three dimensional attributes, can be used in predicting the discrete as well as broadband noise generated in a fan rotor, as well as in evaluating the aerodynamic losses, efficiency and optimum spacing between a rotor and stator in turbomachinery.

  17. Bright Streaks and Dark Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The south polar region of Mars is covered every year by a layer of carbon dioxide ice. In a region called the 'cryptic terrain,' the ice is translucent and sunlight can penetrate through the ice to warm the surface below.

    The ice layer sublimates (evaporates) from the bottom. The dark fans of dust seen in this image come from the surface below the layer of ice, carried to the top by gas venting from below. The translucent ice is 'visible' by virtue of the effect it has on the tone of the surface below, which would otherwise have the same color and reflectivity as the fans.

    Bright streaks in this image are fresh frost. The CRISM team has identified the composition of these streaks to be carbon dioxide.

    Observation Geometry Image PSP_003113_0940 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 26-Mar-2007. The complete image is centered at -85.8 degrees latitude, 106.0 degrees East longitude. The range to the target site was 244.9 km (153.0 miles). At this distance the image scale is 49.0 cm/pixel (with 2 x 2 binning) so objects 147 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel . The image was taken at a local Mars time of 06:20 PM and the scene is illuminated from the west with a solar incidence angle of 79 degrees, thus the sun was about 11 degrees above the horizon. At a solar longitude of 207.6 degrees, the season on Mars is Northern Autumn.

  18. TBCC Fan Stage Operability and Performance

    NASA Technical Reports Server (NTRS)

    Suder, Kenneth L.

    2007-01-01

    NASA s Fundamental Aeronautics Program is investigating turbine-based propulsion systems for access to space because it provides the potential for aircraft-like, space-launch operations that may significantly reduce launch costs and improve safety. Studies performed under NASA s NGLT and the NASP High Speed Propulsion Assessment (HiSPA) program indicated a variable cycle turbofan/ramjet was the best configuration to satisfy access-to-space mission requirements because this configuration maximizes the engine thrust-to-weight ratio while minimizing frontal area. To this end, NASA and GE teamed to design a Mach 4 variable cycle turbofan/ramjet engine for access to space. To enable the wide operating range of a Mach 4+ variable cycle turbofan ramjet required the development of a unique fan stage design capable of multi-point operation to accommodate variations in bypass ratio (10X), fan speed (7X), inlet mass flow (3.5X), inlet pressure (8X), and inlet temperature (3X). The primary goal of the fan stage was to provide a high pressure ratio level with good efficiency at takeoff through the mid range of engine operation, while avoiding stall and losses at the higher flight Mach numbers, without the use of variable inlet guide vanes. Overall fan performance and operability therefore requires major consideration, as competing goals at different operating points and aeromechanical issues become major drivers in the design. To mitigate risk of meeting the unique design requirements for the fan stage, NASA and GE teamed to design and build a 57% engine scaled fan stage to be tested in NASA s transonic compressor facility. The objectives of this test are to assess the aerodynamic and aero mechanic performance and operability characteristics of the fan stage over the entire range of engine operation including: 1) sea level static take-off, 2) transition over large swings in fan bypass ratio, 3) transition from turbofan to ramjet, and 4) fan windmilling operation at high Mach

  19. Turbofan gas turbine engine with variable fan outlet guide vanes

    NASA Technical Reports Server (NTRS)

    Wood, Peter John (Inventor); Zenon, Ruby Lasandra (Inventor); LaChapelle, Donald George (Inventor); Mielke, Mark Joseph (Inventor); Grant, Carl (Inventor)

    2010-01-01

    A turbofan gas turbine engine includes a forward fan section with a row of fan rotor blades, a core engine, and a fan bypass duct downstream of the forward fan section and radially outwardly of the core engine. The forward fan section has only a single stage of variable fan guide vanes which are variable fan outlet guide vanes downstream of the forward fan rotor blades. An exemplary embodiment of the engine includes an afterburner downstream of the fan bypass duct between the core engine and an exhaust nozzle. The variable fan outlet guide vanes are operable to pivot from a nominal OGV position at take-off to an open OGV position at a high flight Mach Number which may be in a range of between about 2.5-4+. Struts extend radially across a radially inwardly curved portion of a flowpath of the engine between the forward fan section and the core engine.

  20. Highly Loaded Fan by Using Tandem Cascade Rotor Blade

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroaki; Suga, Shinya; Matsuoka, Akinori

    For axial flow compressors and fans in the aircraft engines higher pressure ratio is required in order to attain the high thrust engines. In this study, the fan with the tandem cascades was introduced to increase the fan pressure ratio. The use of tandem cascades in the fan allows savings in length and weight and therefore a compact fan could be built. The design of fan with tandem cascades and the fan testing were carried out to develop the high pressure ratio fan for the Air Turbo Ramjet (ATR) propulsion system. The ATR is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds. In particular, high fan pressure ratio contributes to increase the engine thrust during subsonic flight at which the engine does not make use of ram effect. The results of the fan testing indicate that the pressure ratio of 2.2 is achieved in single stage fan.

  1. Diffusion bonded boron/aluminum spar-shell fan blade

    NASA Technical Reports Server (NTRS)

    Carlson, C. E. K.; Cutler, J. L.; Fisher, W. J.; Memmott, J. V. W.

    1980-01-01

    Design and process development tasks intended to demonstrate composite blade application in large high by-pass ratio turbofan engines are described. Studies on a 3.0 aspect radio space and shell construction fan blade indicate a potential weight savings for a first stage fan rotor of 39% when a hollow titanium spar is employed. An alternate design which featured substantial blade internal volume filled with titanium honeycomb inserts achieved a 14% potential weight savings over the B/M rotor system. This second configuration requires a smaller development effort and entails less risk to translate a design into a successful product. The feasibility of metal joining large subsonic spar and shell fan blades was demonstrated. Initial aluminum alloy screening indicates a distinct preference for AA6061 aluminum alloy for use as a joint material. The simulated airfoil pressings established the necessity of rigid air surfaces when joining materials of different compressive rigidities. The two aluminum alloy matrix choices both were successfully formed into blade shells.

  2. Modeling Fan Effects on the Time Course of Associative Recognition

    PubMed Central

    Schneider, Darryl W.; Anderson, John R.

    2011-01-01

    We investigated the time course of associative recognition using the response signal procedure, whereby a stimulus is presented and followed after a variable lag by a signal indicating that an immediate response is required. More specifically, we examined the effects of associative fan (the number of associations that an item has with other items in memory) on speed–accuracy tradeoff functions obtained in a previous response signal experiment involving briefly studied materials and in a new experiment involving well-learned materials. High fan lowered asymptotic accuracy or the rate of rise in accuracy across lags, or both. We developed an Adaptive Control of Thought–Rational (ACT-R) model for the response signal procedure to explain these effects. The model assumes that high fan results in weak associative activation that slows memory retrieval, thereby decreasing the probability that retrieval finishes in time and producing a speed–accuracy tradeoff function. The ACT-R model provided an excellent account of the data, yielding quantitative fits that were as good as those of the best descriptive model for response signal data. PMID:22197797

  3. Detectability of minerals on desert alluvial fans using reflectance spectra

    NASA Technical Reports Server (NTRS)

    Shipman, Hugh; Adams, John B.

    1987-01-01

    The visible and near-infrared reflectance spectra of soil samples collected from desert alluvial and colluvial surfaces in the Cuprite mining district, Nevada, were analyzed. These surfaces are downslope from hydrothermally altered volcanic rocks that contain spectrally characteristic minerals such as alunite and kaolinite. Coarse fractions of the soils on the alluvial fans are mineralogically variable and express the upslope lithologies; fine fractions are remarkably similar mineralogically and spectrally in all samples because of dilution of local mineral components by regionally derived windblown dust. Theoretical models for spectral mixing and for particle-size effects were used to model the observed spectral variations. Diagnostic mineral absorption bands in the spectra of fan materials were enhanced by computationally removing the spectrum of the homogeneous fine-soil component. Results show that spectral mixing models are useful for analyzing data with high spectral resolution obtained by field and aircraft spectrometers.

  4. An air bearing fan for EVA suit ventilation

    NASA Technical Reports Server (NTRS)

    Murry, Roger P.

    1990-01-01

    The portable life-support system (PLSS) ventilation requirements are outlined, along with the application of a high-speed axial fan technology for extravehicular-activity (EVA) space-suit ventilation. Focus is placed on a mechanical design employing high-speed gas bearings, permanent magnet rotor, and current-fed chopper/inverter electronics. The operational characteristics of the fan unit and its applicability for use in a pure-oxygen environment are discussed. It delivers a nominal 0.17 cu m/min at 1.24 kPa pressure rise using 13.8 w of input power. It is shown that the overall selection of materials for all major component meets the NASA requirements.

  5. Large-scale Advanced Prop-fan (LAP) technology assessment report

    NASA Technical Reports Server (NTRS)

    Degeorge, C. L.

    1988-01-01

    The technologically significant findings and accomplishments of the Large Scale Advanced Prop-Fan (LAP) program in the areas of aerodynamics, aeroelasticity, acoustics and materials and fabrication are described. The extent to which the program goals related to these disciplines were achieved is discussed, and recommendations for additional research are presented. The LAP program consisted of the design, manufacture and testing of a near full-scale Prop-Fan or advanced turboprop capable of operating efficiently at speeds to Mach .8. An aeroelastically scaled model of the LAP was also designed and fabricated. The goal of the program was to acquire data on Prop-Fan performance that would indicate the technology readiness of Prop-Fans for practical applications in commercial and military aviation.

  6. Dynamic response of Hovercraft lift fans

    NASA Astrophysics Data System (ADS)

    Moran, D. D.

    1981-08-01

    Hovercraft lift fans are subjected to varying back pressure due to wave action and craft motions when these vehicles are operating in a seaway. The oscillatory back pressure causes the fans to perform dynamically, exhibiting a hysteresis type of response and a corresponding degradation in mean performance. Since Hovercraft motions are influenced by variations in lift fan pressure and discharge, it is important to understand completely the nature of the dynamic performance of lift fans in order to completely solve the Hovercraft seakeeping problem. The present study was performed to determine and classify the instabilities encountered in a centrifugal fan operating against time-varying back pressure. A model-scale experiment was developed in which the fan discharge was directed into a flow-measuring device, terminating in a rotating valve which produced an oscillatory back pressure superimposed upon a mean aerodynamic resistance. Pressure and local velocity were measured as functions of time at several locations in the fan volute. The measurements permitted the identification of rotating (or propagating) stall in the impeller. One cell and two cell configurations were classified and the transient condition connecting these two configurations was observed. The mechanisms which lead to rotating stall in a centrifugal compressor are presented and discussed with specific reference to Hovercraft applications.

  7. Large Fluvial Fans and Exploration for Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Wilkinson, Murray Justin

    2005-01-01

    A report discusses the geological phenomena known, variously, as modern large (or large modern) fluvial fans or large continental fans, from a perspective of exploring for hydrocarbons. These fans are partial cones of river sediment that spread out to radii of 100 km or more. Heretofore, they have not been much recognized in the geological literature probably because they are difficult to see from the ground. They can, however, be seen in photographs taken by astronauts and on other remotely sensed imagery. Among the topics discussed in the report is the need for research to understand what seems to be an association among fluvial fans, alluvial fans, and hydrocarbon deposits. Included in the report is an abstract that summarizes the global distribution of large modern fluvial fans and a proposal to use that distribution as a guide to understanding paleo-fluvial reservoir systems where oil and gas have formed. Also included is an abstract that summarizes what a continuing mapping project has thus far revealed about the characteristics of large fans that have been found in a variety of geological environments.

  8. UHB engine fan broadband noise reduction study

    NASA Astrophysics Data System (ADS)

    Gliebe, Philip R.; Ho, Patrick Y.; Mani, Ramani

    1995-06-01

    A study has been completed to quantify the contribution of fan broadband noise to advanced high bypass turbofan engine system noise levels. The result suggests that reducing fan broadband noise can produce 3 to 4 EPNdB in engine system noise reduction, once the fan tones are eliminated. Further, in conjunction with the elimination of fan tones and an increase in bypass ratio, a potential reduction of 7 to 10 EPNdB in system noise can be achieved. In addition, an initial assessment of engine broadband noise source mechanisms has been made, concluding that the dominant source of fan broadband noise is the interaction of incident inlet boundary layer turbulence with the fan rotor. This source has two contributors, i.e., unsteady life dipole response and steady loading quadrupole response. The quadrupole contribution was found to be the most important component, suggesting that broadband noise reduction can be achieved by the reduction of steady loading field-turbulence field quadrupole interaction. Finally, for a controlled experimental quantification and verification, the study recommends that further broadband noise tests be done on a simulated engine rig, such as the GE Aircraft Engine Universal Propulsion Simulator, rather than testing on an engine statically in an outdoor arena The rig should be capable of generating forward and aft propagating fan noise, and it needs to be tested in a large freejet or a wind tunnel.

  9. UHB Engine Fan Broadband Noise Reduction Study

    NASA Technical Reports Server (NTRS)

    Gliebe, Philip R.; Ho, Patrick Y.; Mani, Ramani

    1995-01-01

    A study has been completed to quantify the contribution of fan broadband noise to advanced high bypass turbofan engine system noise levels. The result suggests that reducing fan broadband noise can produce 3 to 4 EPNdB in engine system noise reduction, once the fan tones are eliminated. Further, in conjunction with the elimination of fan tones and an increase in bypass ratio, a potential reduction of 7 to 10 EPNdB in system noise can be achieved. In addition, an initial assessment of engine broadband noise source mechanisms has been made, concluding that the dominant source of fan broadband noise is the interaction of incident inlet boundary layer turbulence with the fan rotor. This source has two contributors, i.e., unsteady life dipole response and steady loading quadrupole response. The quadrupole contribution was found to be the most important component, suggesting that broadband noise reduction can be achieved by the reduction of steady loading field-turbulence field quadrupole interaction. Finally, for a controlled experimental quantification and verification, the study recommends that further broadband noise tests be done on a simulated engine rig, such as the GE Aircraft Engine Universal Propulsion Simulator, rather than testing on an engine statically in an outdoor arena The rig should be capable of generating forward and aft propagating fan noise, and it needs to be tested in a large freejet or a wind tunnel.

  10. Small fan-in is beautiful

    SciTech Connect

    Beiu, V.; Makaruk, H.E.

    1997-09-01

    The starting points of this paper are two size-optimal solutions: (1) one for implementing arbitrary Boolean functions; and (2) another one for implementing certain subclasses of Boolean functions. Because VLSI implementations do not cope well with highly interconnected nets -- the area of a chip grows with the cube of the fan-in -- this paper will analyze the influence of limited fan-in on the size optimality for the two solutions mentioned. First, the authors will extend a result from Horne and Hush valid for fan-in {Delta} = 2 to arbitrary fan-in. Second, they will prove that size-optimal solutions are obtained for small constant fan-ins for both constructions, while relative minimum size solutions can be obtained for fan-ins strictly lower that linear. These results are in agreement with similar ones proving that for small constant fan-ins ({Delta} = 6...9) there exist VLSI-optimal (i.e., minimizing AT{sup 2}) solutions, while there are similar small constants relating to the capacity of processing information.

  11. Counter-Rotatable Fan Gas Turbine Engine with Axial Flow Positive Displacement Worm Gas Generator

    NASA Technical Reports Server (NTRS)

    Giffin, Rollin George (Inventor); Murrow, Kurt David (Inventor); Fakunle, Oladapo (Inventor)

    2014-01-01

    A counter-rotatable fan turbine engine includes a counter-rotatable fan section, a worm gas generator, and a low pressure turbine to power the counter-rotatable fan section. The low pressure turbine maybe counter-rotatable or have a single direction of rotation in which case it powers the counter-rotatable fan section through a gearbox. The gas generator has inner and outer bodies having offset inner and outer axes extending through first, second, and third sections of a core assembly. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes and extending radially outwardly and inwardly respectively. The helical blades have first, second, and third twist slopes in the first, second, and third sections respectively. A combustor section extends through at least a portion of the second section.

  12. The role of tip clearance in high-speed fan stall

    NASA Technical Reports Server (NTRS)

    Adamczyk, J. J.; Celestina, M. L.; Greitzer, E. M.

    1991-01-01

    A numerical experiment has been carried out to define the near-stall casing endwall flowfield of a high-speed fan rotor. The experiment used a simulation code incorporating a simple clearance model, whose calibration is presented. The results of the simulation show that the interaction of the tip leakage vortex and the in-pasage shock plays a major role in determining the fan flow range. More specifically, the computations imply that it is the area increase of this vortex as it passes through the in-passage shock, which is the source of the blockage associated with stall. In addition, for fans of this type, it is the clearance over the forward portion of the fan blade which controls the flow processes leading to stall.

  13. Extended parametric representation of compressor fans and turbines. Volume 1: CMGEN user's manual

    NASA Technical Reports Server (NTRS)

    Converse, G. L.; Giffin, R. G.

    1984-01-01

    A modeling technique for fans, boosters, and compressors has been developed which will enable the user to obtain consistent and rapid off-design performance from design point input. The fans and compressors are assumed to be multi-stage machines incorporating front variable stators. The boosters are assumed to be fixed geometry machines. The modeling technique has been incorporated into time sharing program to facilitate its use. Because this report contains a description of the input output data, values of typical inputs, and examples cases, it is suitable as a user's manual. This report is the first of a three volume set describing the parametric representation of compressors, fans, and turbines. The titles of the three volumes are as follows: (1) Volume 1 CMGEN USER's Manual (Parametric Compressor Generator); (2) Volume 2 PART USER's Manual (parametric Turbine); (3) Volume 3 MODFAN USER's Manual (Parametric Modulating Flow Fan).

  14. Cost/benefit assessment of the application of composite materials to subsonic commercial transport engines

    NASA Technical Reports Server (NTRS)

    Faddoul, J. R.; Signorelli, R. A.

    1976-01-01

    Results from a number of studies concerned with the cost and benefits of applying advanced composite materials to commercial turbofan engines are summarized. For each application area the optimistic and pessimistic benefit projections were averaged to arrive at a projected yearly percentage fuel savings for a commercial fleet of advanced technology transport aircraft. Engine components included in the summary are the fan section which includes fan blades, fan frame/case, and the blade containment ring; the nacelle; and the high pressure turbine blades and vanes. The projected fuel savings resulting from the application of composites are 1.85 percent for the fan section, 1.75 percent for the nacelle, and 2.35 percent for the high pressure turbine.

  15. Fan-structure waves in shear ruptures

    NASA Astrophysics Data System (ADS)

    Tarasov, Boris

    2016-04-01

    This presentation introduces a recently identified shear rupture mechanism providing a paradoxical feature of hard rocks - the possibility of shear rupture propagation through the highly confined intact rock mass at shear stress levels significantly less than frictional strength. According to the fan-mechanism the shear rupture propagation is associated with consecutive creation of small slabs in the fracture tip which, due to rotation caused by shear displacement of the fracture interfaces, form a fan-structure representing the fracture head. The fan-head combines such unique features as: extremely low shear resistance (below the frictional strength), self-sustaining stress intensification in the rupture tip (providing easy formation of new slabs), and self-unbalancing conditions in the fan-head (making the failure process inevitably spontaneous and violent). An important feature of the fan-mechanism is the fact that for the initial formation of the fan-structure an enhanced local shear stress is required, however, after completion of the fan-structure it can propagate as a dynamic wave through intact rock mass at shear stresses below the frictional strength. Paradoxically low shear strength of pristine rocks provided by the fan-mechanism determines the correspondingly low transient strength of the lithosphere, which favours generation of new earthquake faults in the intact rock mass adjoining pre-existing faults in preference to frictional stick-slip instability along these faults. The new approach reveals an alternative role of pre-existing faults in earthquake activity: they represent local stress concentrates in pristine rock adjoining the fault where special conditions for the fan-mechanism nucleation are created, while further dynamic propagation of the new fault (earthquake) occurs at low field stresses even below the frictional strength.

  16. Submarine fans in a sequence stratigraphic framework

    SciTech Connect

    Posamentier, H.W.; Erskine, R.D.; Mitchum, R.M.; Vail, P.R.

    1987-05-01

    Submarine fans are fan- or cone-shaped turbiditic deposits formed in upper bathyal or deeper water depths. Within a sequence stratigraphic framework, these basin-floor turbidites can occur during lowstand-fan or lowstand-wedge systems tract time. During lowstand fan time, streams are rejuvenated and depocenters shift from the coastal plain to the upper slope, causing retrogradational slope failure and canyon formation. The sediment delivered here bypasses the canyon and continues down the slope as a succession of gravity flows and is deposited as fan-shaped turbiditic deposits at the base of the slope. Seismic and outcrop evidence suggest that these sand-prone deposits are abruptly introduced into the basin and are generally characterized by subtle external mounding and internal bidirectionally down lapping seismic reflections where seismically resolvable. Deep-water sediment deposited during this interval has no coeval shelf equivalent. During lowstand wedge time, streams cease down cutting and valleys which have been freshly incised begin to fill. Because coarse sediment will preferentially be deposited within these incised valleys, the sand-to-mud ratio delivered to the upper slope will be decreased and, consequently, there is an inherent difference between submarine fans deposited at this time and those deposited during lowstand fan time. Deposition during lowstand wedge time is characterized seismically by slope front fill or wedge-shaped geometries down lapping the earlier submarine fan (i.e., deposited during lowstand fan time). These shale-prone deposits are largely comprised of thinner-bedded turbidites as well as the occasional leveed channel.

  17. Mineralogy and geochemistry of surface sediments from the Bengal Fan, Indian Ocean

    NASA Astrophysics Data System (ADS)

    Roonwal, G. S.; Glasby, G. P.; Chugh, R.

    1997-02-01

    The mineralogy and composition of 75 sediment samples from the Bengal Fan. Andaman Sea and the eastern flanks of the upper Nicobar Fan have been determined. Sediments from the Upper and Middle Bengal Fan are mainly terrigenous and derived from the Ganges Brahmaputra river system, whereas sediments from the Andaman Sea and the eastern flank of the upper Nicobar Fan vary from terrigenous to largely biogenic. For the terrigenous sediments, the continental influence is illustrated by the distribution of the major elements (excluding Ca) which decrease away from the source. The Ti/Al and Fe/Al ratios of the sediments are higher in samples from the cast coast of India than from the fans, indicating the influence of material from the Deccan basalts as well as from mafic rocks of the Indian Peninsula. In the clay mineral fraction of Upper Bengal Fan sediments, illite and chlorite are the dominant constituents, with minor amounts of smectite and traces of kaolinite. Illite is mainly a weathering product of lithic material from the Himalaya and is transported by the Ganges Brahmaputra river system. Smectite is the dominant constituent of the sediments adjacent to the Indian Peninsula.

  18. Sound source localization on an axial fan at different operating points

    NASA Astrophysics Data System (ADS)

    Zenger, Florian J.; Herold, Gert; Becker, Stefan; Sarradj, Ennes

    2016-08-01

    A generic fan with unskewed fan blades is investigated using a microphone array method. The relative motion of the fan with respect to the stationary microphone array is compensated by interpolating the microphone data to a virtual rotating array with the same rotational speed as the fan. Hence, beamforming algorithms with deconvolution, in this case CLEAN-SC, could be applied. Sound maps and integrated spectra of sub-components are evaluated for five operating points. At selected frequency bands, the presented method yields sound maps featuring a clear circular source pattern corresponding to the nine fan blades. Depending on the adjusted operating point, sound sources are located on the leading or trailing edges of the fan blades. Integrated spectra show that in most cases leading edge noise is dominant for the low-frequency part and trailing edge noise for the high-frequency part. The shift from leading to trailing edge noise is strongly dependent on the operating point and frequency range considered.

  19. Experimental Investigation of Terminal Fans Prograding on a Salt Substrate: 3-d Physical Experiments

    NASA Astrophysics Data System (ADS)

    Chatmas, E.; Kim, W.

    2015-12-01

    Interactions between geologic features and a mobile substrate layer are present in several passive margin locations throughout the world. Deformation of a substrate layer is primarily due to differential loading of sediment and results in complexities within the morphology and subsequently the stratigraphic record. By using simplified scaled tank experiments, we investigated the relationship between substrate deformation and fan evolution in a fluvial-dump-wind-redistribution setting. In this system, sediment is being eroded from a mountain range and creating terminal fans; fluvial channels form off of the fan body and the deposited fluvial sediment is the source for an aeolian dune field. Several past experimental studies have focused on how deltas and dunes are affected on when deposited on a salt substrate, however terminal fans and channel formation off of fans have not been thoroughly investigated. The current experiments focused on which variables are the most significant in controlling fan growth, channel initiation and channel behavior on the salt substrate. Our experimental basin is 120 cm long, 60 cm wide and 30 cm tall. The materials used for a suite of five experiments involved a polymer polydimethylsiloxane (PDMS) as the deformable substrate analog and 100-μm quartz sand. By isolating certain variables such as substrate thickness, basin slope and sediment discharge we are able to see how terminal fans and channels are affected in different settings. The experimental results show that 1) increase in substrate thickness increased the amount of subsidence around the fan body, limiting sediment transport to channels off of the toe of the fan, 2) a higher basin slope increased the number of channels formed and increased sinuosity and width variations of channels over distance, and 3) a higher sediment discharge rate on a thin substrate allowed for the farthest downstream fan deposits. Preliminary results show that channel behavior and fan morphology is

  20. Fan Noise Prediction: Status and Needs

    NASA Technical Reports Server (NTRS)

    Huff, Dennis L.

    1997-01-01

    The prediction of fan noise is an important part to the prediction of overall turbofan engine noise. Advances in computers and better understanding of the flow physics have allowed researchers to compute sound generation from first principles and rely less on empirical correlations. While progress has been made, there are still many aspects of the problem that need to be explored. This paper presents some recent advances in fan noise prediction and suggests areas that still need further development. Fan noise predictions that support the recommendations are taken from existing publications.

  1. The Problem of Alluvial Fan Slopes

    NASA Astrophysics Data System (ADS)

    Stock, J. D.; Schmidt, K.

    2005-12-01

    Water and debris flows exiting confined valleys have a tendency to deposit sediment on steep fans. On alluvial fans, where water transport predominates, channel slopes tend to decrease downfan from ~0.08 to ~0.01 across wide ranges of climate and tectonism. Some have argued that this pattern reflects downfan grainsize fining so that higher slopes are required just to entrain coarser particles in the waters of the upper fan, while entrainment of finer grains downfan requires lower slopes (threshold hypothesis). An older hypothesis is that slope is adjusted to transport the supplied sediment load, which decreases downfan as deposition occurs (transport hypothesis). We have begun to test these hypotheses using detailed field measurements of hydraulic and sediment variables in sediment transport models. On some fans in the western U.S. we find that alluvial fan channel bankfull depths are largely 0.5-1.5 m at fan heads, decreasing to 0.1-0.2 m at distal margins. Contrary to many previous studies, we find that median gravel diameter does not change systematically along the upper 60- 80% of active fan channels. So downstream gravel fining cannot explain most of the observed channel slope reduction. However, as slope declines, surface sand cover increases systematically downfan from values of <20% above fan heads to distal fan values in excess of 70%. As a result, the threshold for sediment motion might decrease systematically downfan, leading to lower slopes. However, current models of this effect alone tend to underpredict downfan slope changes. This is likely due to off- channel gravel deposition. Calculations that match observed fan long-profiles require an exponential decline in gravel transport rate, so that on some fans approximately half of the load must be deposited off-channel every ~0.25-1.25 km downfan. This leads us to hypothesize that alluvial fan long- profiles are largely statements about the rate of deposition downfan. If so, there may be climatic and

  2. Remote lift fan study program, volume 4

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A study program to select and conduct preliminary design of advanced technology lift fan systems to meet low noise goals of future V/STOL transport aircraft is discussed. This volume contains results of additional studies conducted to support the main preliminary design effort done under the Remote Lift Fan Study Program (Contract NAS3-14406) and a companion effort, the Integral Lift Fan Study (NAS3-14404). These results cover engine emission study, a review of existing engines for research aircraft application and support data for aircraft studies.

  3. Modern and ancient alluvial fan deposits

    SciTech Connect

    Nilsen, T.H.

    1985-01-01

    Understanding the structure and depositional processes of alluvial fans (river outwash deposits) has a special interest for those involved with the exploration of petroleum and many minerals. This collection of facsimile reprints of significant and classical research papers sheds new light on the subject. This reference covers the stratigraphy, sedimentology, and depositional processes of modern and ancient alluvial fans. Geographical areas considered include Arctic Canada, the American Southwest, Australia, Wyoming, Norway, and Spain. It includes a state-of-the-art introduction by the editor along with commentaries on all the papers included, a master author citation index and a subject index, and a chronological listing of early studies of alluvial fans.

  4. Fan Database and Web-tool for Choosing Quieter Spaceflight Fans

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S.; Burnside, Nathan J.

    2007-01-01

    One critical aspect of designing spaceflight hardware is the selection of fans to provide the necessary cooling. And with efforts to minimize cost and the tendancy to be conservative with the amount of cooling provided, it is easy to choose an overpowered fan. One impact of this is that the fan uses more energy than is necessary. But, the more significant impact is that the hardware produces much more acoustic noise than if an optimal fan was chosen. Choosing the right fan for a specific hardware application is no simple task. It requires knowledge of cooling requirements and various fan performance characteristics as well as knowledge of the aerodynamic losses of the hardware in which the fan is to be installed. Knowledge of the acoustic emissions of each fan as a function of operating condition is also required in order to choose a quieter fan for a given design point. The purpose of this paper is to describe a database and design-tool that have been developed to aid spaceflight hardware developers in choosing a fan for their application that is based on aerodynamic performance and reduced acoustic emissions as well. This web-based-tool provides a limited amount of fan-data, provides a method for selecting a fan based on its projected operating point, and also provides a method for comparing and contrasting aerodynamic performance and acoustic data from different fans. Drill-down techniques are used to display details of the spectral noise characteristics of the fan at specific operation conditions. The fan aerodynamic and acoustic data were acquired at Ames Research Center in the Experimental Aero-Physics Branch's Anechoic Chamber. Acoustic data were acquired according to ANSI Standard S12.11-1987, "Method for the Measurement of Noise Emitted by Small Air-Moving Devices." One significant improvement made to this technique included automation that allows for a significant increase in flow-rate resolution. The web-tool was developed at Johnson Space Center and is

  5. Analysis of Stainless Steel Sandwich Panels with a Metal Foam Core for Lightweight Fan Blade Design

    NASA Technical Reports Server (NTRS)

    Min, James B.; Ghosn, Louis J.; Lerch, Bradley A.; Raj, Sai V.; Holland, Frederic A., Jr.; Hebsur, Mohan G.

    2004-01-01

    The quest for cheap, low density and high performance materials in the design of aircraft and rotorcraft engine fan and propeller blades poses immense challenges to the materials and structural design engineers. The present study investigates the use of a sandwich foam fan blade mae up of solid face sheets and a metal foam core. The face sheets and the metal foam core material were an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. The resulting structures possesses a high stiffness while being lighter than a similar solid construction. The material properties of 17-4 PH metal foam are reviewed briefly to describe the characteristics of sandwich structure for a fan blade application. A vibration analysis for natural frequencies and a detailed stress analysis on the 17-4 PH sandwich foam blade design for different combinations of kin thickness and core volume are presented with a comparison to a solid titanium blade.

  6. Flutter Stability of the Efficient Low Noise Fan Calculated

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Srivastava, Rakesh

    2004-01-01

    at part speed condition was located beyond the stall line, which means that the ELNF will not encounter flutter since it will never operate beyond the stall line. All the calculations done so far have been for the nonblowing case, and selected calculations will be repeated with air blowing from the trailing edge of the fan.

  7. 30 CFR 75.331 - Auxiliary fans and tubing.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Auxiliary fans and tubing. 75.331 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.331 Auxiliary fans and tubing. (a) When auxiliary fans and tubing are used for face ventilation, each auxiliary fan shall be—...

  8. 30 CFR 75.331 - Auxiliary fans and tubing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Auxiliary fans and tubing. 75.331 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.331 Auxiliary fans and tubing. (a) When auxiliary fans and tubing are used for face ventilation, each auxiliary fan shall be—...

  9. 30 CFR 75.331 - Auxiliary fans and tubing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Auxiliary fans and tubing. 75.331 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.331 Auxiliary fans and tubing. (a) When auxiliary fans and tubing are used for face ventilation, each auxiliary fan shall be—...

  10. 30 CFR 75.331 - Auxiliary fans and tubing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Auxiliary fans and tubing. 75.331 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.331 Auxiliary fans and tubing. (a) When auxiliary fans and tubing are used for face ventilation, each auxiliary fan shall be—...

  11. 30 CFR 75.331 - Auxiliary fans and tubing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Auxiliary fans and tubing. 75.331 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.331 Auxiliary fans and tubing. (a) When auxiliary fans and tubing are used for face ventilation, each auxiliary fan shall be—...

  12. Supersonic fan engines for military aircraft

    NASA Technical Reports Server (NTRS)

    Franciscus, L. C.

    1983-01-01

    Engine performance and mission studies were performed for turbofan engines with supersonic through-flow fans. A Mach 2.4 CTOL aircraft was used in the study. Two missions were considered: a long range penetrator mission and a long range intercept mission. The supersonic fan engine is compared with an augmented mixed flow turbofan in terms of mission radius for a fixed takeoff gross weight of 75,000 lbm. The mission radius of aircraft powered by supersonic fan engines could be 15 percent longer than aircraft powered with conventional turbofan engines at moderate thrust to gross weight ratios. The climb and acceleration performance of the supersonic fan engines is better than that of the conventional turbofan engines.

  13. Synchronous and Cogged Fan Belt Performance Assessment

    SciTech Connect

    Cutler, D.; Dean, J.; Acosta, J.

    2014-02-01

    The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

  14. Supersonic fan engines for military aircraft

    NASA Technical Reports Server (NTRS)

    Franciscus, L. C.

    1983-01-01

    Engine performance and mission studies were performed for turbofan engines with supersonic through-flow fans. A Mach 2.4 CTOL aircraft was used in the study. Two missions were considered: a long range penetrator mission and a long range intercept mission. The supersonic fan engine is compared with an augmented mixed flow turbofan in terms of mission radius for a fixed takeoff gross weight of 75,000 lbm. The mission radius of aircraft powered by supersonic fan engines could be 15 percent longer than aircraft powered with conventional turbofan engines at moderate thrust to gross weight ratios. The climb and acceleration performance of the supersonic fan engines is better than that of the conventional turbofan engines. Previously announced in STAR as N83-34947

  15. 11. EXTERIOR VIEW OF NEW FAN HOUSE LOOKING EAST The ...

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

    11. EXTERIOR VIEW OF NEW FAN HOUSE LOOKING EAST The airway (on the left) leads from the Baltimore shaft to the New Fan House. The metal housing (center foreground) encases a single entry Duplex Conoidal fan, made by the Buffalo Forge Company. The Duplex Conoidal fan had two parts: a disk fan which drew air up the airway and a centrifugal fan set at a right angle to it which exhausted the air. The engine house (on the right) contains a direct connected Corliss engine. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  16. Navy Fan, California Borderland: Growth pattern and depositional processes

    USGS Publications Warehouse

    Normark, W.R.; Piper, D.J.W.

    1984-01-01

    Navy Fan is a Late Pleistocene sand-rich fan prograding into an irregularly shaped basin in the southern California Borderland. The middle fan, characterized by one active and two abandoned 'distributary' channels and associated lobe deposits, at present onlaps part of the basin slope directly opposite from the upper-fan valley, thus dividing the lower-fan/basin-plain regions into two separate parts of different depths. Fine-scale mesotopographic relief on the fan surface and correlation of individual turbidite beds through nearly 40 cores on the middle and lower fan provide data for evaluating the Late Pleistocene and Holocene depositional processes. ?? 1984 Springer-Verlag New York Inc.

  17. Design and Test of Fan/Nacelle Models Quiet High-Speed Fan Design

    NASA Technical Reports Server (NTRS)

    Miller, Christopher J. (Technical Monitor); Repp, Russ; Gentile, David; Hanson, David; Chunduru, Srinivas

    2003-01-01

    The primary objective of the Quiet High-Speed Fan (QHSF) program was to develop an advanced high-speed fan design that will achieve a 6 dB reduction in overall fan noise over a baseline configuration while maintaining similar performance. The program applies and validates acoustic, aerodynamic, aeroelastic, and mechanical design tools developed by NASA, US industry, and academia. The successful fan design will be used in an AlliedSignal Engines (AE) advanced regional engine to be marketed in the year 2000 and beyond. This technology is needed to maintain US industry leadership in the regional turbofan engine market.

  18. Energy efficient engine: Fan test hardware detailed design report

    NASA Technical Reports Server (NTRS)

    Sullivan, T. J.

    1980-01-01

    A single stage fan and quarter stage booster were designed for the energy efficient engine. The fan has an inlet radius ratio of 0.342 and a specific flow rate of 208.9 Kg/S sq m (42.8 lbm/sec sq ft). The fan rotor has 32 medium aspect ratio (2.597) titanium blades with a partspan shroud at 55% blade height. The design corrected fan tip speed is 411.5 M/S (1350 ft/sec). The quarter stage island splits the total fan flow with approximately 22% of the flow being supercharged by the quarter stage rotor. The fan bypass ratio is 6.8. The core flow total pressure ratio is 1.67 and the fan bypass pressure ratio is 1.65. The design details of the fan and booster blading, and the fan frame and static structure for the fan configuration are presented.

  19. Lift/cruise fan VTOL aircraft

    NASA Technical Reports Server (NTRS)

    Quigley, H. C.; Franklin, J. A.

    1977-01-01

    The paper gives an overview of the technology related to lift/cruise fan VTOL aircraft, covering propulsion systems, thrust deflection, flight dynamics, controls, displays, aerodynamics, and configurations. Piloting problems are discussed, and the need for integration of power management and thrust-vector controls is pointed out. Major components for a high-bypass-ratio lift/cruise fan propulsion system for VTOL aircraft have been tested.

  20. The Advanced Noise Control Fan Baseline Measurements

    NASA Technical Reports Server (NTRS)

    McAllister, Joseph; Loew, Raymond A.; Lauer, Joel T.; Stuliff, Daniel L.

    2009-01-01

    The NASA Glenn Research Center s (NASA Glenn) Advanced Noise Control Fan (ANCF) was developed in the early 1990s to provide a convenient test bed to measure and understand fan-generated acoustics, duct propagation, and radiation to the farfield. As part of a complete upgrade, current baseline and acoustic measurements were documented. Extensive in-duct, farfield acoustic, and flow field measurements are reported. This is a follow-on paper to documenting the operating description of the ANCF.

  1. Flutter Calculations for an Experimental Fan

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Srivastava, Rakesh; Panovsky, Josef; Keith, Theo G., Jr.; Stefko, George L.

    2003-01-01

    During testing, an experimental forward-swept fan encountered flutter at part-speed conditions. A three-dimensional propulsion aeroelasticity code, based on a computational fluid dynamics (CFD) approach, was used to model the aeroelastic behavior of this fan. This paper describes the flutter calculations and compares the results to the experimental measurements. Results of sensitivity studies are also presented that show the relative importance of different aspects of aeroelastic modeling.

  2. Tone Noise Predictions for a Spacecraft Cabin Ventilation Fan Ingesting Distorted Inflow and the Challenges of Validation

    NASA Technical Reports Server (NTRS)

    Koch, L. Danielle; Shook, Tony D.; Astler, Douglas T.; Bittinger, Samantha A.

    2011-01-01

    A fan tone noise prediction code has been developed at NASA Glenn Research Center that is capable of estimating duct mode sound power levels for a fan ingesting distorted inflow. This code was used to predict the circumferential and radial mode sound power levels in the inlet and exhaust duct of an axial spacecraft cabin ventilation fan. Noise predictions at fan design rotational speed were generated. Three fan inflow conditions were studied: an undistorted inflow, a circumferentially symmetric inflow distortion pattern (cylindrical rods inserted radially into the flowpath at 15deg, 135deg, and 255deg), and a circumferentially asymmetric inflow distortion pattern (rods located at 15deg, 52deg and 173deg). Noise predictions indicate that tones are produced for the distorted inflow cases that are not present when the fan operates with an undistorted inflow. Experimental data are needed to validate these acoustic predictions, as well as the aerodynamic performance predictions. Given the aerodynamic design of the spacecraft cabin ventilation fan, a mechanical and electrical conceptual design study was conducted. Design features of a fan suitable for obtaining detailed acoustic and aerodynamic measurements needed to validate predictions are discussed.

  3. Tone Noise Predictions for a Spacecraft Cabin Ventilation Fan Ingesting Distorted Inflow and the Challenges of Validation

    NASA Technical Reports Server (NTRS)

    Koch, L. Danielle; Shook, Tony D.; Astler, Douglas T.; Bittinger, Samantha A.

    2012-01-01

    A fan tone noise prediction code has been developed at NASA Glenn Research Center that is capable of estimating duct mode sound power levels for a fan ingesting distorted inflow. This code was used to predict the circumferential and radial mode sound power levels in the inlet and exhaust duct of an axial spacecraft cabin ventilation fan. Noise predictions at fan design rotational speed were generated. Three fan inflow conditions were studied: an undistorted inflow, a circumferentially symmetric inflow distortion pattern (cylindrical rods inserted radially into the flowpath at 15deg, 135deg, and 255deg), and a circumferentially asymmetric inflow distortion pattern (rods located at 15deg, 52deg and 173deg). Noise predictions indicate that tones are produced for the distorted inflow cases that are not present when the fan operates with an undistorted inflow. Experimental data are needed to validate these acoustic predictions, as well as the aerodynamic performance predictions. Given the aerodynamic design of the spacecraft cabin ventilation fan, a mechanical and electrical conceptual design study was conducted. Design features of a fan suitable for obtaining detailed acoustic and aerodynamic measurements needed to validate predictions are discussed.

  4. Euler/Navier-Stokes Solvers Applied to Ducted Fan Configurations

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Srivastava, Rakesh

    1997-01-01

    Due to noise considerations, ultra high bypass ducted fans have become a more viable design. These ducted fans typically consist of a rotor stage containing a wide chord fan and a stator stage. One of the concerns for this design is the classical flutter that keeps occurring in various unducted fan blade designs. These flutter are catastrophic and are to be avoided in the flight envelope of the engine. Some numerical investigations by Williams, Cho and Dalton, have suggested that a duct around a propeller makes it more unstable. This needs to be further investigated. In order to design an engine to safely perform a set of desired tasks, accurate information of the stresses on the blade during the entire cycle of blade motion is required. This requirement in turn demands that accurate knowledge of steady and unsteady blade loading be available. Aerodynamic solvers based on unsteady three-dimensional analysis will provide accurate and fast solutions and are best suited for aeroelastic analysis. The Euler solvers capture significant physics of the flowfield and are reasonably fast. An aerodynamic solver Ref. based on Euler equations had been developed under a separate grant from NASA Lewis in the past. Under the current grant, this solver has been modified to calculate the aeroelastic characteristics of unducted and ducted rotors. Even though, the aeroelastic solver based on three-dimensional Euler equations is computationally efficient, it is still very expensive to investigate the effects of multiple stages on the aeroelastic characteristics. In order to investigate the effects of multiple stages, a two-dimensional multi stage aeroelastic solver was also developed under this task, in collaboration with Dr. T. S. R. Reddy of the University of Toledo. Both of these solvers were applied to several test cases and validated against experimental data, where available.

  5. Applicability of fan spray nozzles to stripping insoluble gases from viscous liquids

    SciTech Connect

    Tseng, H.H.; Johnson, E.F.

    1983-08-01

    Fan spray nozzle stripping appears to be a practical technique for separating dilute volatile solutes from nonvolatile solvents. In particular this technique can be used to strip molecular tritium and tritium fluoride at extremely small concentration (in the parts per million range) from molten salts used as blanket materials in a fusion reactor. Under adjusted operating conditions of the fan spray as it leaves the nozzle, a high percentage of the theoretically maximum achievable stripping would take place from the expanding sheet of the fan spray as it leaves the nozzle and before it breaks up. Although the only available experimental data are for aqueous solutions, a new theoretical analysis of the fan spray sheet demonstrates the applicability of this technique to nonaqueous liquids. The equation derived from this analysis relates the theoretically achievable mass transfer efficiency to the properties of the liquid flowing through the fan spray nozzle and to the operating conditions of the nozzle. Any fluid with viscosity higher than or equal to that of water would be expected to follow this equation as long as a fan-shaped sheet is formed under the operating conditions of the nozzle.

  6. A Comparison of Measured Tone Modes for Two Low Noise Propulsion Fans

    NASA Technical Reports Server (NTRS)

    Heidelberg, Laurence J.; Elliott, David M.

    2000-01-01

    The acoustic modes for two low tip speed propulsion fans were measured to examine the effects of fan tip speed, at constant pressure ratio. A continuously rotating microphone method was used that provided the complete modal structure (circumferential and radial order) at the fundamental and second harmonic of the blade passing tone as well as most of the third harmonic modes. The fans are compared in terms of their rotor/stator interaction modal power, and total tone power. It was hoped that the lower tip speed might produce less noise. This was not the case. The higher tip speed fan, at both takeoff and cutback speeds, had lower tone and interaction levels. This could be an indication that the higher aerodynamic loading required to produce the same pressure ratio for the lower tip speed fan resulted in a greater velocity deficit in the blade wakes and thus more noise. Results consistent with expected rotor transmission effects were noted in the inlet modal structures of both fans.

  7. Sediments and stratigraphy of a glaciomarine fan in the lower Androscoggin Valley, Lewiston, Maine

    SciTech Connect

    Slayton, J.T. . Geology Dept.)

    1993-03-01

    Numerous exposures in ice contact deltas and glacial marine fans in the lower Androscoggin Valley of S. Central Maine detail a history of the Wisconsinan ice sheet retreat in contact with marine waters ca. 12,000 to 13,000 years B.P. The ice contact deltas and fans probably form by many similar processes and have common stratigraphic sequences that build seaward from a meltwater tunnel source. This study investigates the sediments and stratigraphic relationships in a glaciomarine fan complex in the Lewiston, Maine area. The study focuses on a composite landform that is triangular in map view and encompasses approximately 3 km[sup 2]. Exposures in 5 bottom pits were mapped, and stratigraphic lithofacies logged in numerous exposures. The bulk of the deposit is composed of lithofacies including: poorly sorted gravelly sand and boulders in ice proximal regions, coarse to fine bedded sands medial regions and terminating in the distal fan area in silty clay facies. Facies originate predominantly from traction currents, gravity flow, and suspension settling of material from the meltwater tunnel. Diamicton facies formed at various stratigraphic levels within the pit originate from debris flows down the topographic gradient of the fan surface. Two models are proposed for the formation of the fan complex. The first suggests that the sediments are the result of two different ice-marginal positions; with the first depositional sequence lasting longer than the subsequent position 0.5 km to the north. The second model uses one ice-marginal position, but sediments prograde distally and laterally over earlier fan deposits. Regardless of which model is most accurate, the fan builds a large sand and gravel complex that grades to within 5 meters of marine limit as recorded in an ice-contact delta, 10 km to the NW.

  8. Fungi in healthy and diseased sea fans ( Gorgonia ventalina): is Aspergillus sydowii always the pathogen?

    NASA Astrophysics Data System (ADS)

    Toledo-Hernández, C.; Zuluaga-Montero, A.; Bones-González, A.; Rodríguez, J. A.; Sabat, A. M.; Bayman, P.

    2008-09-01

    Caribbean corals, including sea fans ( Gorgonia spp.), are being affected by severe and apparently new diseases. In the case of sea fans, the pathogen is reported to be the fungus Aspergillus sydowii, and the disease is named aspergillosis. In order to understand coral diseases and pathogens, knowledge of the microbes associated with healthy corals is also necessary. In this study the fungal community of healthy Gorgonia ventalina colonies was contrasted with that of diseased colonies. In addition, the fungal community of healthy and diseased tissue within colonies with aspergillosis was contrasted. Fungi were isolated from healthy and diseased fans from 15 reefs around Puerto Rico, and identified by sequencing the nuclear ribosomal ITS region and by morphology. Thirty fungal species belonging to 15 genera were isolated from 203 G. ventalina colonies. Penicillum and Aspergillus were the most common genera isolated from both healthy and diseased fans. However, the fungal community of healthy fans was distinct and more diverse than that of diseased ones. Within diseased fans, fungal communities from diseased tissues were distinct and more diverse than from healthy tissue. The reduction of fungi in diseased colonies may occur prior to infection due to environmental changes affecting the host, or after infection due to increase in dominance of the pathogen, or because of host responses to infection. Data also indicate that the fungal community of an entire sea fan colony is affected even when only a small portion of the colony suffers from aspergillosis. An unexpected result was that A. sydowii was found in healthy sea fans but never in diseased ones. This result suggests that A. sydowii is not the pathogen causing aspergillosis in the studied colonies, and suggests several fungi common to healthy and diseased colonies as opportunistic pathogens. Given that it is not clear that Aspergillus is the sole pathogen, calling this disease aspergillosis is an

  9. The Florida High School Mock Trial Competition Case Materials, 1997. State of Florida v. Lee Appleman.

    ERIC Educational Resources Information Center

    Florida Law Related Education Association, Tallahassee.

    This material provides students with information to prepare for a mock trial. The defendant in this case has been accused of the crime of driving under the influence of alcoholic beverages causing severe bodily injury. Case materials include stipulated facts, jury instructions, depositions, and other related materials. (EH)

  10. Active Piezoelectric Vibration Control of Subscale Composite Fan Blades

    NASA Technical Reports Server (NTRS)

    Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Min, James B.; Kray, Nicholas

    2012-01-01

    As part of the Fundamental Aeronautics program, researchers at NASA Glenn Research Center (GRC) are investigating new technologies supporting the development of lighter, quieter, and more efficient fans for turbomachinery applications. High performance fan blades designed to achieve such goals will be subjected to higher levels of aerodynamic excitations which could lead to more serious and complex vibration problems. Piezoelectric materials have been proposed as a means of decreasing engine blade vibration either through a passive damping scheme, or as part of an active vibration control system. For polymer matrix fiber composite blades, the piezoelectric elements could be embedded within the blade material, protecting the brittle piezoceramic material from the airflow and from debris. To investigate this idea, spin testing was performed on two General Electric Aviation (GE) subscale composite fan blades in the NASA GRC Dynamic Spin Rig Facility. The first bending mode (1B) was targeted for vibration control. Because these subscale blades are very thin, the piezoelectric material was surface-mounted on the blades. Three thin piezoelectric patches were applied to each blade two actuator patches and one small sensor patch. These flexible macro-fiber-composite patches were placed in a location of high resonant strain for the 1B mode. The blades were tested up to 5000 rpm, with patches used as sensors, as excitation for the blade, and as part of open- and closed-loop vibration control. Results show that with a single actuator patch, active vibration control causes the damping ratio to increase from a baseline of 0.3% critical damping to about 1.0% damping at 0 RPM. As the rotor speed approaches 5000 RPM, the actively controlled blade damping ratio decreases to about 0.5% damping. This occurs primarily because of centrifugal blade stiffening, and can be observed by the decrease in the generalized electromechanical coupling with rotor speed.