11. Photocopy of photograph. Photographer unknown, circa 1955. Original photograph ...

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

11. Photocopy of photograph. Photographer unknown, circa 1955. Original photograph can be found in Marvine Colliery folder in the archives of the Lackawanna Historical Society, Scranton, Pennsylvania. VIEW SHOWING EAST AND NORTH FACADES OF BREAKER, WITH BOILER HOUSE AT FAR LEFT AND RETAIL SCALES OFFICE DIRECTLY EAST OF BREAKER, LOOKING SOUTHWEST - Marvine Colliery, Breaker No. 2, West side Boulevard Avenue, between East Parker Street & Route 380, Scranton, Lackawanna County, PA

The modern Kaoping transient fan offshore SW Taiwan: Morphotectonics and development

NASA Astrophysics Data System (ADS)

Hsiung, Kan-Hsi; Yu, Ho-Shing; Chiang, Cheng-Shing

2018-01-01

Using bathymetry and seismic reflection profiles, this study examined and determined the transient nature of the Kaoping Fan located in the topographically complex slope offshore southwest Taiwan. Kaoping Fan is located west of the lower reach of the Kaoping Canyon at the lower Kaoping Slope, ranging from 2,200 to 3,000 m water depth, and has a relatively small areal extent restricted in the topographic lows confined by structural highs due to mud diapiric uplifting and thrust faulting. Kaoping Fan shows an asymmetrical triangular fan-shaped bathymetric feature elongated in an NW-SE direction but with a strong skew toward the east. The fan deposits consist of three main seismic facies: layered high-amplitude reflections in the upper section and stratified, parallel to sub-parallel low-amplitude reflections with variable continuity and channel fill facies in the lower section. In the absence of ground-truthing from core data, the seismic patterns suggest that the Kaoping Fan recorded the onset of channelized and over-bank deposits in the lower part and layered turbidite facies in the upper part subsequently. The development of the Kaoping Fan can be divided into three stages in terms of canyon activities and fan-feeding processes. Initially, Kaoping Fan was mainly fed by a point sediment source at the apex of the fan. Secondly, Kaoping Fan was maintained as a slope fan, mainly fed laterally by over-spilled sediments from the canyon. Finally, the Kaoping Canyon completely passes through the Kaoping Fan and supplies over-spilled sediments laterally, forming a transient fan with canyon incision and sediment by-passing. The accumulation of sediments and the growth of Kaoping Fan are primarily controlled by inherited complex paleo-topography and the evolution of Kaoping Canyon. The sediment delivery system of Kaoping Fan is characterized by lateral supply of over-spilling sediment flows and sediments bypassing to and beyond the base of slope. The Kaoping Fan together with the ponded Fangliao Fan in the topographically complex Kaoping Slope can be used as a type model for evaluating the topographic effects on the development of submarine fans on complex slopes in general.

Mycobacteria in water used for personal hygiene in heavy industry and collieries: a potential risk for employees.

PubMed

Ulmann, Vit; Kracalikova, Anna; Dziedzinska, Radka

2015-03-04

Environmental mycobacteria (EM) constitute a health risk, particularly for immunocompromised people. Workers in heavy industry and in collieries represent an at-risk group of people as their immunity is often weakened by long-term employment in dusty environments, frequent smoking and an increased occurrence of pulmonary diseases. This study was concerned with the presence of EM in non-drinking water used for the hygiene of employees in six large industrial companies and collieries. Over a period of ten years, 1096 samples of surface water treated for hygiene purposes (treated surface water) and treated surface water diluted with mining water were examined. EM were detected in 63.4 and 41.5% samples of treated surface water and treated surface water diluted with mining water, respectively. Mycobacterium gordonae, M. avium-intracellulare and M. kansasii were the most frequently detected species. Adoption of suitable precautions should be enforced to reduce the incidence of mycobacteria in shower water and to decrease the infectious pressure on employees belonging to an at-risk group of people.

The Detection And Analysis Of Blasting Problems Encountered In A Colliery Using High Speed Photography

NASA Astrophysics Data System (ADS)

Rorke, A. J.; Kohler, E. W.

1987-09-01

Premature initiation of ANFO (an explosive mixture of Ammonium Nitrate and Fuel Oil) at a large colliery, near Witbank, was first detected from routine high speed films taken of large mid-burden, and overburden blasts. The analysis of these films shows that the rapid migration of very hot gasses through cracks ahead of the blast may have caused the explosive to initiate prematurely. The problem was not seen in the less competent overburden rocks. A less sensitive explosive has been successfully tried. The assessment of these blasts using high speed photography is discussed.

A comparative study of removal of fluoride from contaminated water using shale collected from different coal mines in India.

PubMed

Biswas, Gargi; Dutta, Manjari; Dutta, Susmita; Adhikari, Kalyan

2016-05-01

Low-cost water defluoridation technique is one of the most important issues throughout the world. In the present study, shale, a coal mine waste, is employed as novel and low-cost adsorbent to abate fluoride from simulated solution. Shale samples were collected from Mahabir colliery (MBS) and Sonepur Bazari colliery (SBS) of Raniganj coalfield in West Bengal, India, and used to remove fluoride. To increase the adsorption efficiency, shale samples were heat activated at a higher temperature and samples obtained at 550 °C are denoted as heat-activated Mahabir colliery shale (HAMBS550) and heat-activated Sonepur Bazari colliery shale (HASBS550), respectively. To prove the fluoride adsorption onto different shale samples and ascertain its mechanism, natural shale samples, heat-activated shale samples, and their fluoride-loaded forms were characterized using scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction study, and Fourier transform infrared spectroscopy. The effect of different parameters such as pH, adsorbent dose, size of particles, and initial concentration of fluoride was investigated during fluoride removal in a batch contactor. Lower pH shows better adsorption in batch study, but it is acidic in nature and not suitable for direct consumption. However, increase of pH of the solution from 3.2 to 6.8 and 7.2 during fluoride removal process with HAMBS550 and HASBS550, respectively, confirms the applicability of the treated water for domestic purposes. HAMBS550 and HASBS550 show maximum removal of 88.3 and 88.5 %, respectively, at initial fluoride concentration of 10 mg/L, pH 3, and adsorbent dose of 70 g/L.

Observations on the Occupational Life History of the Coal Face Worker at Two Collieries

PubMed Central

Edmonds, O. P.; Kerr, D. S.

1960-01-01

Coal-face work is well known to be arduous and dangerous; it is performed in an unnatural environment even where conditions are good. Few men can continue this work until the age of retirement. They usually seek alternative employment either outside the industry or within the other major occupational groups at a colliery. The latter comprise the surface workers and those employed underground other than at the coal-face. This paper is concerned with those who stay within the industry. From a study of 73 workers who left the coal-face at two collieries, it indicates (1) the extent to which migration to alternative employment occurs each year, and (2) the resultant distribution of ex coal-face workers among these other occupational groups. The length of effective working life of the coal-miner on the coal-face, the reasons which precipitate his leaving it, and the type of work which he is able to do are also described. This information is of economic importance but it is mainly of value in assessing the effects of coal-face work upon the health of the coal-miner. PMID:13819356

The use of sustainable 'biochar compost' for remediation of contaminated land

NASA Astrophysics Data System (ADS)

Ryan, Aoife; Street-Perrott, Alayne; Eastwood, Daniel; Brackenbury, Sion

2014-05-01

South Wales (UK) has a long industrial history which, since the collapse of the coal-mining industry, has left a large number of contaminated former colliery sites. Bio-remediation of these areas by re-vegetation with native grasses aims to prevent erosion and leaching of pollutants into drainage waters. However, acid pH, low organic-matter content and unsuitable soil structure have limited the success of re-vegetation and prompted research into the development of artificial soils. This study aims to assess the value of creating an artificial soil cover by adding "biochar compost" to the top 10cm of a large volume of contaminated colliery spoil (high in As and Cu) to be moved during construction of a flood-alleviation barrage in Cwm Dulais (Swansea). It is proposed to use biochar, manufactured from chipped biomass sourced from a local stand of invasive Rhododendron ponticum using a BiGchar 1000 fast pyrolysis-gasification unit, in combination with locally produced BSI PAS100-certified Pteridium aquilinum (bracken) compost, to remediate a large area (2.3ha) of landscaped colliery waste and re-establish a cover of native grasses suitable for sheep grazing. Pot and field trials are being used to determine the most appropriate biochar:compost mix. In a 90-day outdoor pot trial, a commercial acid-grassland seed mix was grown in screened (< 20mm) colliery spoil, to which 25%v/v bracken compost (with/without composted manure) was added as a source of organic matter. This application rate of compost (equivalent to 250m3ha-1) was based on a successful coal-tip remediation trial at Ffos-y-Frân (Jarvis & Walton, WRAP Report, 2011). Varying application rates of biochar (0%, 2%, 5%, 10% or 20%v/v) were employed. Additional benefits of adding mycorrhizal inoculant or Trifolium repens (white clover) seed were also tested. Six-fold replication was used, with appropriate controls. The performance of each treatment was assessed from its maximum sward height and final above-ground dry phytomass. To evaluate the quality of the resulting grassland for sheep grazing, grass samples are being analysed for nutrients, heavy metals and metalloids by elemental analysis (EA) and X-ray fluorescence spectroscopy (XRF). These results will be compared with grass samples collected from Cwm Dulais. Initial findings suggest that addition of biochar compost improved grass growth compared with unamended colliery spoil.

Crystal structure of a Fanconi anemia-associated nuclease homolog bound to 5' flap DNA: basis of interstrand cross-link repair by FAN1

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

Gwon, Gwang Hyeon; Kim, Youngran; Liu, Yaqi

2014-10-15

Fanconi anemia (FA) is an autosomal recessive genetic disorder caused by defects in any of 15 FA genes responsible for processing DNA interstrand cross-links (ICLs). The ultimate outcome of the FA pathway is resolution of cross-links, which requires structure-selective nucleases. FA-associated nuclease 1 (FAN1) is believed to be recruited to lesions by a monoubiquitinated FANCI–FANCD2 (ID) complex and participates in ICL repair. Here, we determined the crystal structure of Pseudomonas aeruginosa FAN1 (PaFAN1) lacking the UBZ (ubiquitin-binding zinc) domain in complex with 5' flap DNA. All four domains of the right-hand-shaped PaFAN1 are involved in DNA recognition, with each domainmore » playing a specific role in bending DNA at the nick. The six-helix bundle that binds the junction connects to the catalytic viral replication and repair (VRR) nuclease (VRR nuc) domain, enabling FAN1 to incise the scissile phosphate a few bases distant from the junction. The six-helix bundle also inhibits the cleavage of intact Holliday junctions. PaFAN1 shares several conserved features with other flap structure-selective nucleases despite structural differences. A clamping motion of the domains around the wedge helix, which acts as a pivot, facilitates nucleolytic cleavage. The PaFAN1 structure provides insights into how archaeal Holliday junction resolvases evolved to incise 5' flap substrates and how FAN1 integrates with the FA complex to participate in ICL repair.« less

Mortality in an extended follow-up of British coal workers

NASA Astrophysics Data System (ADS)

MacCalman; L; Miller; G, B.

2009-02-01

The Pneumoconiosis Field Research (PFR) programme was established in the 1950s, to evaluate effects of coal mining exposures on the health and mortality of British coal workers. Surveys of working miners were carried out at 5-yearly intervals, initially in 24 collieries but later concentrating on 10, collecting detailed work histories and health information for each recruit. Here we report on cause-specific mortality in a cohort of almost 18,000 men from 10 British collieries, followed up for periods up to 47 years, yielding over 516,000 life-years of follow-up. External analyses compared cause-specific death rates in the cohort to those of the population of the regions in which the collieries were situated, using Standardised Mortality Ratios (SMRs). The causes investigated included lung cancer, stomach cancer, non-malignant respiratory disorders and cardiovascular disorders. SMRs showed evidence of an initial healthy worker effect diminishing over time. Several causes, including non-malignant respiratory disease and lung cancer, showed a significant deficit of mortality at the start of the study period with an excess in the latter part of the follow-up period. In these results, effects of working conditions are likely to be confounded with smoking habits. Overall, we believe our results may be generalised to the British coal industry since nationalisation.

Influence of Applying Additional Forcing Fans for the Air Distribution in Ventilation Network

NASA Astrophysics Data System (ADS)

Szlązak, Nikodem; Obracaj, Dariusz; Korzec, Marek

2016-09-01

Mining progress in underground mines cause the ongoing movement of working areas. Consequently, it becomes necessary to adapt the ventilation network of a mine to direct airflow into newly-opened districts. For economic reasons, opening new fields is often achieved via underground workings. Length of primary intake and return routes increases and also increases the total resistance of a complex ventilation network. The development of a subsurface structure can make it necessary to change the air distribution in a ventilation network. Increasing airflow into newly-opened districts is necessary. In mines where extraction does not entail gas-related hazards, there is possibility of implementing a push-pull ventilation system in order to supplement airflows to newly developed mining fields. This is achieved by installing subsurface fan stations with forcing fans at the bottom of downcast shaft. In push-pull systems with multiple main fans, it is vital to select forcing fans with characteristic curves matching those of the existing exhaust fans to prevent undesirable mutual interaction. In complex ventilation networks it is necessary to calculate distribution of airflow (especially in networks with a large number of installed fans). In the article the influence of applying additional forcing fans for the air distribution in ventilation network for underground mine were considered. There are also analysed the extent of overpressure caused by the additional forcing fan in branches of the ventilation network (the operating range of additional forcing fan). Possibilities of increasing airflow rate in working areas were conducted.

Contracting out of clinical services in Zimbabwe.

PubMed

McPake, B; Hongoro, C

1995-07-01

Contracting is increasingly recommended to developing countries as a way of improving the efficiency of the health sector. However, empirical evidence regarding its effectiveness in this respect is almost completely absent. In Zimbabwe, a long standing contract exists between the Ministry of Health and Wankie Colliery to provide clinical services in the Colliery's 400 bed hospital. This paper details a study of the Zimbabweans' experience with the contract. Its success is assessed using comparisons with a neighbouring government hospital of the price of services (vs the cost in the government hospital); the situation of hospital workers; and the quality of services delivered. The Colliery has established a monopoly position for hospital services in the district. However, it appears to offer services of at least as good quality at prices which are lower than the unit costs of the government hospital when capital costs are included. Nevertheless, the contract cannot be considered a success due to the failure to contain its total cost. Approximately 70% of provincial non-salary recurrent expenditure is consumed by the contract while only a minority of the province's population have access to the Colliery hospital. Screening patients, both with respect to their ability to pay and to their need for secondary level services does not take place with the result that utilization levels are not controlled. The study highlights a number of important issues affecting contracting in developing country setting: First, contracted institutions attain powerful bargaining positions if there are no viable competitors and the government does not itself retain capacity to offer an alternative service. Second, specific skills are needed for the management of contracts at all levels. If the process of contract development responds to a crisis driven agenda resulting from civil service retrenchment and public expenditure cuts, it is unlikely that adequate consideration will be given to the development of such skills and the retention of key personnel. If such details are neglected, otherwise feasible efficiency gains will prove elusive.

FAN1 acts with FANCI-FANCD2 to promote DNA interstrand cross-link repair.

PubMed

Liu, Ting; Ghosal, Gargi; Yuan, Jingsong; Chen, Junjie; Huang, Jun

2010-08-06

Fanconi anemia (FA) is caused by mutations in 13 Fanc genes and renders cells hypersensitive to DNA interstrand cross-linking (ICL) agents. A central event in the FA pathway is mono-ubiquitylation of the FANCI-FANCD2 (ID) protein complex. Here, we characterize a previously unrecognized nuclease, Fanconi anemia-associated nuclease 1 (FAN1), that promotes ICL repair in a manner strictly dependent on its ability to accumulate at or near sites of DNA damage and that relies on mono-ubiquitylation of the ID complex. Thus, the mono-ubiquitylated ID complex recruits the downstream repair protein FAN1 and facilitates the repair of DNA interstrand cross-links.

A cooperative study of gate entry designs: Welbeck Colliery (UK) and Jim Walter Resources (USA)

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

Hendon, G.; Carr, F.; Lewis, A.

1995-11-01

Longwall developments in the UK have historically consisted of single entry gate roads. Adjacent developments were separated from existing pales by large barrier pillars (designed of sufficient width to get away from the longwall abutments of the previous panel) or by small barriers driven in the shadow, or de-stressed zone, of the previous panel. Some 2nd panel tailgates were also driven skin to skin leaving no coal barrier between the newly driven entry and the heavily supported existing gateroad. With the development and wide acceptance of fully bolted entries and the pressure to reduce production costs, alternatives to single entrymore » drivage, particularly yield pillar developments, were examined. Through the Rock Mechanics Branch of british Coal, a cooperative study was begun with Jim Walter Resources, Inc., USA, (JWR) to look at the yield pillar alternative in detail. This study was to determine the feasibility of utilizing yield pillars in the UK and to determine, through monitoring, the possibility of reducing stable pillar widths at JWR. The study has included extensive monitoring of the yield-stable-yield pillar system at JWR No. 7 Mine and an underground trial of a two entry yield pillar test area at Welbeck Colliery in the UK. This paper describes results from the JWR study and the subsequent results of the first advancing yield pillar development in the UK at Welbeck Colliery.« less

Anatomy and growth pattern of Amazon deep-sea fan as revealed by long-range side-scan sonar (GLORIA) and high-resolution seismic studies

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

Damuth, J.E.; Flood, R.D.; Kowsmann, R.O.

1988-08-01

Imaging of the Amazon deep-sea fan with long-range side-scan sonar (GLORIA) has, for the first time, revealed the anatomy, trends, and growth pattern of distributary channels on this fan. Only one channel-levee system was active at any given time and extended from the Amazon Submarine Canyon downslope onto the lower fan (> 4,200 m). Formation of new channel-levee systems occurred when a currently active channel-levee system was cut off and abandoned through avulsion, and a new channel-levee system was established nearby. Through time, successive channel-levee formation and abandonment built two broad levee complexes consisting of groups of overlapping, coalescing segmentsmore » of channel-levee systems across the present fan surface. These, plus older, now buried levee complexes, indicate that fan growth is radially outward and downslope through development of successive levee complexes. The most striking characteristic of the distributary channels is their intricate, often recurving, meanders with sinuosities of up to 2.5. Cutoffs and abandoned meander loops indicate that the channels migrate laterally through time. Channel bifurcation results predominantly from avulsion when flows breach a channel levee, thereby abandoning the present channel and establishing a new channel-levee segment nearby. No clear evidence of channel branching (i.e., division of a single channel into two active segments) or braiding was observed. 22 figs.« less

Unsteady Reynolds-averaged Navier-Stokes simulations of inlet distortion in the fan system of a gas-turbine aero-engine

NASA Astrophysics Data System (ADS)

Spotts, Nathan

As modern trends in commercial aircraft design move toward high-bypass-ratio fan systems of increasing diameter with shorter, nonaxisymmetric nacelle geometries, inlet distortion is becoming common in all operating regimes. The distortion may induce aerodynamic instabilities within the fan system, leading to catastrophic damage to fan blades, should the surge margin be exceeded. Even in the absence of system instability, the heterogeneity of the flow affects aerodynamic performance significantly. Therefore, an understanding of fan-distortion interaction is critical to aircraft engine system design. This thesis research elucidates the complex fluid dynamics and fan-distortion interaction by means of computational fluid dynamics (CFD) modeling of a complete engine fan system; including rotor, stator, spinner, nacelle and nozzle; under conditions typical of those encountered by commercial aircraft. The CFD simulations, based on a Reynolds-averaged Navier-Stokes (RANS) approach, were unsteady, three-dimensional, and of a full-annulus geometry. A thorough, systematic validation has been performed for configurations from a single passage of a rotor to a full-annulus system by comparing the predicted flow characteristics and aerodynamic performance to those found in literature. The original contributions of this research include the integration of a complete engine fan system, based on the NASA rotor 67 transonic stage and representative of the propulsion systems in commercial aircraft, and a benchmark case for unsteady RANS simulations of distorted flow in such a geometry under realistic operating conditions. This study is unique in that the complex flow dynamics, resulting from fan-distortion interaction, were illustrated in a practical geometry under realistic operating conditions. For example, the compressive stage is shown to influence upstream static pressure distributions and thus suppress separation of flow on the nacelle. Knowledge of such flow physics is valuable for engine system design.

Structural insights into 5‧ flap DNA unwinding and incision by the human FAN1 dimer

NASA Astrophysics Data System (ADS)

Zhao, Qi; Xue, Xiaoyu; Longerich, Simonne; Sung, Patrick; Xiong, Yong

2014-12-01

Human FANCD2-associated nuclease 1 (FAN1) is a DNA structure-specific nuclease involved in the processing of DNA interstrand crosslinks (ICLs). FAN1 maintains genomic stability and prevents tissue decline in multiple organs, yet it confers ICL-induced anti-cancer drug resistance in several cancer subtypes. Here we report three crystal structures of human FAN1 in complex with a 5‧ flap DNA substrate, showing that two FAN1 molecules form a head-to-tail dimer to locate the lesion, orient the DNA and unwind a 5‧ flap for subsequent incision. Biochemical experiments further validate our model for FAN1 action, as structure-informed mutations that disrupt protein dimerization, substrate orientation or flap unwinding impair the structure-specific nuclease activity. Our work elucidates essential aspects of FAN1-DNA lesion recognition and a unique mechanism of incision. These structural insights shed light on the cellular mechanisms underlying organ degeneration protection and cancer drug resistance mediated by FAN1.

Fan array wind tunnel: a multifunctional, complex environmental flow manipulator

NASA Astrophysics Data System (ADS)

Dougherty, Christopher; Veismann, Marcel; Gharib, Morteza

2017-11-01

The recent emergence of small unmanned aerial vehicles (UAVs) has reshaped the aerospace testing environment. Traditional closed-loop wind tunnels are not particularly suited nor easily retrofit to take advantage of these coordinated, controls-based rotorcraft. As such, a highly configurable, novel wind tunnel aimed at addressing the unmet technical challenges associated with single or formation flight performance of autonomous drone systems is presented. The open-loop fan array wind tunnel features 1296 individually controllable DC fans arranged in a 2.88m x 2.88m array. The fan array can operate with and without a tunnel enclosure and is able to rotate between horizontal and vertical testing configurations. In addition to standard variable speed uniform flow, the fan array can generate both unsteady and shear flows. Through the aid of smaller side fan array units, vortex flows are also possible. Conceptual design, fabrication, and validation of the tunnel performance will be presented, including theoretical and computational predictions of flow speed and turbulence intensity. Validation of these parameters is accomplished through standard pitot-static and hot-wire techniques. Particle image velocimetry (PIV) of various complex flows will also be shown. This material is based upon work supported by the Center for Autonomous Systems and Technologies (CAST) at the Graduate Aerospace Laboratories of the California Institute of Technology (GALCIT).

Sedimentary architecture of a sub-lacustrine debris fan: Eocene Dongying Depression, Bohai Bay Basin, east China

NASA Astrophysics Data System (ADS)

Liu, Jianping; Xian, Benzhong; Wang, Junhui; Ji, Youliang; Lu, Zhiyong; Liu, Saijun

2017-12-01

The sedimentary architectures of submarine/sublacustrine fans are controlled by sedimentary processes, geomorphology and sediment composition in sediment gravity flows. To advance understanding of sedimentary architecture of debris fans formed predominantly by debris flows in deep-water environments, a sub-lacustrine fan (Y11 fan) within a lacustrine succession has been identified and studied through the integration of core data, well logging data and 3D seismic data in the Eocene Dongying Depression, Bohai Bay Basin, east China. Six types of resedimented lithofacies can be recognized, which are further grouped into five broad lithofacies associations. Quantification of gravity flow processes on the Y11 fan is suggested by quantitative lithofacies analysis, which demonstrates that the fan is dominated by debris flows, while turbidity currents and sandy slumps are less important. The distribution, geometry and sedimentary architecture are documented using well data and 3D seismic data. A well-developed depositional lobe with a high aspect ratio is identified based on a sandstone isopach map. Canyons and/or channels are absent, which is probably due to the unsteady sediment supply from delta-front collapse. Distributary tongue-shaped debris flow deposits can be observed at different stages of fan growth, suggesting a lobe constructed by debrite tongue complexes. Within each stage of the tongue complexes, architectural elements are interpreted by wireline log motifs showing amalgamated debrite tongues, which constitute the primary fan elements. Based on lateral lithofacies distribution and vertical sequence analysis, it is proposed that lakefloor erosion, entrainment and dilution in the flow direction lead to an organized distribution of sandy debrites, muddy debrites and turbidites on individual debrite tongues. Plastic rheology of debris flows combined with fault-related topography are considered the major factors that control sediment distribution and fan architecture. An important implication of this study is that a deep-water depositional model for debrite-dominated systems was proposed, which may be applicable to other similar deep-water environments.

GLORIA mosaic of west coast U. S. Exclusive Economic Zone, southern sector

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

Gardner, J.V.; Edwards, B.D.; Field, M.E.

1986-05-01

The long-range side-scan sonar system GLORIA was used to produce digitally enhanced mosaics of the sea floor of the entire US Exclusive Economic Zone. The data resolution, about 50 x 50 m, provides a mesoscale reconnaissance that reveals the continuity and extent of bottom features, some of which were previously unrecognized. The transform continental margin from the Mendocino Escarpment to the US-Mexican border is cut by numerous submarine canyons and gullies of varied size and complexity. The number, size, and extent of gullies appear directly related to the underlying bed-rock geology. Surprisingly, relatively few slumps and slump scarps are apparent.more » Submarine fans characterize the basins adjacent to the margin in this sector. The fans vary in size and complexity: relatively small, immature fans of the borderland basins, such as Redondo and Hueneme; fans intermediate in size and age, such as Arguello and Farallon; and large, relatively mature fans, such as Monterey and Delgada. Most fans have well-defined depositional lobes at the distal reach of a single channel. Distributary channels are not apparent on all fans, and on some (e.g., Monterey Fan), the single channel can be seen in seismic reflection profiles to have originated on or close to the basement, directly below its present position. The older depositional lobes that have been identified on the fan systems are adjacent to the present main channel, which implies that channel avulsion is not always a process that accompanies fan growth. Seamounts are prominent features in the region, ranging in number from hundreds in the Baja Seamount province to tens in the region west of San Francisco. The gradient of increasing numbers of exposed seamounts and volcanic ridges from north to south is a direct result of decreasing sediment supply from the continent to the south.« less

Optimal Self-Tuning PID Controller Based on Low Power Consumption for a Server Fan Cooling System.

PubMed

Lee, Chengming; Chen, Rongshun

2015-05-20

Recently, saving the cooling power in servers by controlling the fan speed has attracted considerable attention because of the increasing demand for high-density servers. This paper presents an optimal self-tuning proportional-integral-derivative (PID) controller, combining a PID neural network (PIDNN) with fan-power-based optimization in the transient-state temperature response in the time domain, for a server fan cooling system. Because the thermal model of the cooling system is nonlinear and complex, a server mockup system simulating a 1U rack server was constructed and a fan power model was created using a third-order nonlinear curve fit to determine the cooling power consumption by the fan speed control. PIDNN with a time domain criterion is used to tune all online and optimized PID gains. The proposed controller was validated through experiments of step response when the server operated from the low to high power state. The results show that up to 14% of a server's fan cooling power can be saved if the fan control permits a slight temperature response overshoot in the electronic components, which may provide a time-saving strategy for tuning the PID controller to control the server fan speed during low fan power consumption.

Quantification of Process in AN Actively Eroding Gully-Mass Movement Complex, Waipaoa Catchment, New Zealand

NASA Astrophysics Data System (ADS)

Fuller, I. C.; Taylor, R.; Massey, C. I.; Marden, M.

2012-12-01

Tarndale Gully is a major fluvio-mass movement gully complex in the headwaters of the Waipaoa catchment, contributing c.3% of the Waipaoa sediment yield (Marden et al., 2008). Using a combination of airborne LiDAR (2005) and Terrestrial Laser Scanning (2007, 2008, 2010, 2011), this paper quantifies sediment delivery processes and slope-channel connectivity in this major contributor to the Waipaoa sediment cascade over a seven year period. Building on previous work, which inferred connectivity characteristics using RTK-dGPS surveys of the fan fed by the gully-mass movement complex (Fuller & Marden, 2011), acquisition of terrain data from high-resolution surveys of the whole gully-fan system provides new insights into slope process and slope-channel linkages operating in the complex. Raw terrain data from the airborne and ground-based laser scans were converted into raster DEMs in Arc-GIS using inverse distance weighting interpolation to a vertical accuracy between surveys of < ±0.1m. Using GIS maths functions, grid elevations in each successive DEM were subtracted from the previous DEM to provide models of change across the gully and fan complex. Deposition equates to positive vertical change, while erosion to negative vertical change in these models. Total annualised erosion equates to an average of 125,000m3 generated from the gully-mass movement complex, which is a product of debris flow, slumping and surface erosion by runoff (gullying in the conventional sense). Erosion rates from the gully complex appear to have been consistent year to year between 2005 and 2011. While the average annual volume of sediment exported to the stream system equates to 57,328 m3, this figure varies from 25,000 m3 to 110,000 m3 with no distinct correlation to rainfall. Fluctuations in stored sediment volumes account for this variation, where a critical mass in the upper fan initiates downstream progradation of sediment, building-up the lower fan. When an unknown threshold is reached, the erosion of the lower fan at its junction with the Te Weraroa Stream initiates headward excavation of this accumulated fan sediment. Rainfall data collected throughout the catchment for the period of this study, when compared with a 90 year long-term record from the catchment, suggest that 2005-2011 is not particularly exceptional in terms of storms or annual rainfall. Accordingly, since there have been no large rainfall events recorded during the period of this study, the erosion values and sediment transfer processes reported here can be considered to represent background conditions in the development and operation of this geomorphic system. References Fuller, I.C. & Marden, M. 2011. Slope-channel coupling in steepland terrain: a field-based conceptual model from the Tarndale gully and fan, Waipaoa catchment, New Zealand, Geomorphology, 128, 105-115. Marden, M. et al. 2008. Gully erosion and sediment load: Waipaoa, Waiapu and Uawa Rivers, eastern North Island, New Zealand. In: Schmidt, J. et al. (Eds), Sediment Dynamics in Changing Environments, IAHS Pub. 325, Wallingford, UK, pp. 339-350.

Development and maintenance of a telescoping debris flow fan in response to human-induced fan surface channelization, Chalk Creek Valley Natural Debris Flow Laboratory, Colorado, USA

NASA Astrophysics Data System (ADS)

Wasklewicz, T.; Scheinert, C.

2016-01-01

Channel change has been a constant theme throughout William L. Graf's research career. Graf's work has examined channel changes in the context of natural environmental fluctuations, but more often has focused on quantifying channel change in the context of anthropogenic modifications. Here, we consider how channelization of a debris flows along a bajada has perpetuated and sustained the development of 'telescoping' alluvial fan. Two-dimensional debris-flow modeling shows the importance of the deeply entrenched channelized flow in the development of a telescoping alluvial fan. GIS analyses of repeat (five different debris flows), high-resolution (5 cm) digital elevation models (DEMs) generated from repeat terrestrial laser scanning (TLS) data elucidate sediment and topographic dynamics of the new telescoping portion of the alluvial fan (the embryonic fan). Flow constriction from channelization helps to perpetuate debris-flow runout and to maintain the embryonic fan and telescoping nature of the alluvial fan complex. Embryonic fan development, in response to five debris flows, proceeds with a major portion of the flows depositing on the southern portion of the embryonic fan. The third through the fifth debris flows also begin to shift some deposition to the northern portion of the embryonic. The transfer of sediment from a higher portion of the embryonic fan to a lower portion continues currently on the embryonic fan. While channelized flow has been shown to be critical to the maintenance of the telescoping fan, the flow constriction has led to higher than background levels of sediment deposition in Chalk Creek, a tributary of the Arkansas River. A majority of the sediment from each debris flow is incorporated into Chalk Creek as opposed to being stored on the embryonic fan.

Submarine-fan sedimentation, Ouachita Mountains, Arkansas and Oklahoma

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

Moiola, R.J.; Shanmugam, G.

1984-09-01

More than 10,000 m (32,808 ft) of interbedded sandstones and shales comprise the Upper Mississippian and Lower Pennsylvanian flysch succession (Stanley, Jackfork, Johns Valley, Atoka) in the Ouachita Mountains of Arkansas and Oklahoma. Deposited primarily by turbidity current and hemipelagic processes in bathyal and abyssal water depths, these strata formed major submarine-fan complexes that prograded in a westward direction along the axis of an elongate remnant ocean basin that was associated with the collision and suturing of the North American and African-South American plates. A longitudinal fan system is visualized as the depositional framework for these strata, which were depositedmore » in a setting analogous to the modern Bengal fan of the Indian Ocean. Facies analysis of the Jackfork formation indicates that inner fan deposits are present in the vicinity of Little Rock, Arkansas; middle fan channel and interchannel deposits occur at DeGray Dam and Friendship, Arkansas; and outer fan depositional-lobe deposits are present in southeastern Oklahoma. Boulder-bearing units (olistostromes), many with exotic clasts, were shed laterally into the Ouachita basin. They occur throughout the flysch succession and in all fan environments (i.e., inner, middle, and outer). This relationship may serve as a useful criterion for recognizing analogous longitudinal fan systems in the rock record.« less

High fidelity phase locked PIV measurements analysing the flow fields surrounding an oscillating piezoelectric fan

NASA Astrophysics Data System (ADS)

Jeffers, Nicholas; Nolan, Kevin; Stafford, Jason; Donnelly, Brian

2014-07-01

Piezoelectric fans have been studied extensively and are seen as a promising technology for thermal management due to their ability to provide quiet, reliable cooling with low power consumption. The fluid mechanics of an unconfined piezoelectric fan are complex which is why the majority of the literature to date confines the fan in an attempt to simplify the flow field. This paper investigates the fluid mechanics of an unconfined fan operating in its first vibration frequency mode. The piezoelectric fan used in this study measures 12.7mm × 70mm and resonates at 92.5Hz in air. A custom built experimental facility was developed to capture the fan's flow field using phase locked Particle Image Velocimetry (PIV). The phase locked PIV results are presented in terms of vorticity and show the formation of a horse shoe vortex. A three dimensional A2 criterion constructed from interpolated PIV measurements was used to identify the vortex core in the vicinity of the fan. This analysis was used to clearly identify the formation of a horse shoe vortex that turns into a hairpin vortex before it breaks up due to a combination of vortex shedding and flow along the fan blade. The results presented in this paper contribute to both the fluid dynamics and heat transfer literature concerning first mode fan oscillation.

1. VIEW OF EAST FRONT OF BREAKER, WITH SCALE STICK, ...

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

1. VIEW OF EAST FRONT OF BREAKER, WITH SCALE STICK, SHOWING FOUNDATIONS OF RETAIL SCALES IN FOREGROUND, LOOKING WEST - Marvine Colliery, Breaker No. 2, West side Boulevard Avenue, between East Parker Street & Route 380, Scranton, Lackawanna County, PA

Feature Augmentation via Nonparametrics and Selection (FANS) in High-Dimensional Classification.

PubMed

Fan, Jianqing; Feng, Yang; Jiang, Jiancheng; Tong, Xin

We propose a high dimensional classification method that involves nonparametric feature augmentation. Knowing that marginal density ratios are the most powerful univariate classifiers, we use the ratio estimates to transform the original feature measurements. Subsequently, penalized logistic regression is invoked, taking as input the newly transformed or augmented features. This procedure trains models equipped with local complexity and global simplicity, thereby avoiding the curse of dimensionality while creating a flexible nonlinear decision boundary. The resulting method is called Feature Augmentation via Nonparametrics and Selection (FANS). We motivate FANS by generalizing the Naive Bayes model, writing the log ratio of joint densities as a linear combination of those of marginal densities. It is related to generalized additive models, but has better interpretability and computability. Risk bounds are developed for FANS. In numerical analysis, FANS is compared with competing methods, so as to provide a guideline on its best application domain. Real data analysis demonstrates that FANS performs very competitively on benchmark email spam and gene expression data sets. Moreover, FANS is implemented by an extremely fast algorithm through parallel computing.

Feature Augmentation via Nonparametrics and Selection (FANS) in High-Dimensional Classification

PubMed Central

Feng, Yang; Jiang, Jiancheng; Tong, Xin

2015-01-01

We propose a high dimensional classification method that involves nonparametric feature augmentation. Knowing that marginal density ratios are the most powerful univariate classifiers, we use the ratio estimates to transform the original feature measurements. Subsequently, penalized logistic regression is invoked, taking as input the newly transformed or augmented features. This procedure trains models equipped with local complexity and global simplicity, thereby avoiding the curse of dimensionality while creating a flexible nonlinear decision boundary. The resulting method is called Feature Augmentation via Nonparametrics and Selection (FANS). We motivate FANS by generalizing the Naive Bayes model, writing the log ratio of joint densities as a linear combination of those of marginal densities. It is related to generalized additive models, but has better interpretability and computability. Risk bounds are developed for FANS. In numerical analysis, FANS is compared with competing methods, so as to provide a guideline on its best application domain. Real data analysis demonstrates that FANS performs very competitively on benchmark email spam and gene expression data sets. Moreover, FANS is implemented by an extremely fast algorithm through parallel computing. PMID:27185970

Human FAN1 promotes strand incision in 5'-flapped DNA complexed with RPA.

PubMed

Takahashi, Daisuke; Sato, Koichi; Hirayama, Emiko; Takata, Minoru; Kurumizaka, Hitoshi

2015-09-01

Fanconi anaemia (FA) is a human infantile recessive disorder. Seventeen FA causal proteins cooperatively function in the DNA interstrand crosslink (ICL) repair pathway. Dual DNA strand incisions around the crosslink are critical steps in ICL repair. FA-associated nuclease 1 (FAN1) is a DNA structure-specific endonuclease that is considered to be involved in DNA incision at the stalled replication fork. Replication protein A (RPA) rapidly assembles on the single-stranded DNA region of the stalled fork. However, the effect of RPA on the FAN1-mediated DNA incision has not been determined. In this study, we purified human FAN1, as a bacterially expressed recombinant protein. FAN1 exhibited robust endonuclease activity with 5'-flapped DNA, which is formed at the stalled replication fork. We found that FAN1 efficiently promoted DNA incision at the proper site of RPA-coated 5'-flapped DNA. Therefore, FAN1 possesses the ability to promote the ICL repair of 5'-flapped DNA covered by RPA. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Effects of Bifurcations on Aft-Fan Engine Nacelle Noise

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Farassat, Fereidoun; Pope, D. Stuart; Vatsa, Veer N.

2004-01-01

Aft-fan engine nacelle noise is a significant factor in the increasingly important issue of aircraft community noise. The ability to predict such noise within complex duct geometries is a valuable tool in studying possible noise attenuation methods. A recent example of code development for such predictions is the ducted fan noise propagation and radiation code CDUCT-LaRC. This work focuses on predicting the effects of geometry changes (i.e. bifurcations, pylons) on aft fan noise propagation. Beginning with simplified geometries, calculations show that bifurcations lead to scattering of acoustic energy into higher order modes. In addition, when circumferential mode number and the number of bifurcations are properly commensurate, bifurcations increase the relative importance of the plane wave mode near the exhaust plane of the bypass duct. This is particularly evident when the bypass duct surfaces include acoustic treatment. Calculations involving more complex geometries further illustrate that bifurcations and pylons clearly affect modal content, in both propagation and radiation calculations. Additionally, results show that consideration of acoustic radiation results may provide further insight into acoustic treatment effectiveness for situations in which modal decomposition may not be straightforward. The ability of CDUCT-LaRC to handle complex (non-axisymmetric) multi-block geometries, as well as axially and circumferentially segmented liners, allows investigation into the effects of geometric elements (bifurcations, pylons).

Morphology of upper laurentian fan using GLORIA long-range side-scan sonar

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

Masson, D.G.; Field, M.E.; Gardner, J.V.

1985-06-01

A long-range side-scan sonar (GLORIA) survey of the upper Laurentian Fan shows, for the first time, the regional geomorphology of this large and complex sedimentary body. The channels of the upper continental slope coalesce on the upper fan to form four major fan valleys. The largest of these, Eastern Valley, is U-shaped in cross section and up to 25 km (15 mi) wide with a large levee on the western flank that reaches a maximum height of more than 1 km (3,300 ft) above the valley floor. The remaining valleys, Western, Central, and Grand Banks, are typically more V-shaped inmore » cross section and are up to 5 km (3 mi) wide. Extensive gullying is observed on the walls of all the channels. Sonographs of the floor of Eastern Valley show a strong, linear fabric elongated parallel with the valley walls that appears to be related to mesoscale relief on the valley floor. At water depths between 3,500 and 4,100 m (11,550 and 13,530 ft), two major fan valleys are created by the merging of the four major valleys of the upper fan. Both fan valleys are associated with large, asymmetric levee complexes that reach heights of more than 500 m (1,650 ft) above the valley floors. The GLORIA data show evidence for several amphitheaterlike slump scars in the region of the 1929 earthquake epicenter. However, the authors see no evidence for movement of large coherent sediment blocks as postulated by earlier workers. They suggest that the turbidity currents that occurred after the 1929 earthquake may have formed by the coalescence of many small slumps rather than from a single large slump.« less

Chloroplast targeting of FanC, the major antigenic subunit of Escherichia coli K99 fimbriae, in transgenic soybean.

PubMed

Garg, Renu; Tolbert, Melanie; Oakes, Judy L; Clemente, Thomas E; Bost, Kenneth L; Piller, Kenneth J

2007-07-01

Enterotoxigenic Escherichia coli (ETEC) strains are a major cause of enteric diseases affecting livestock and humans. Edible transgenic plants producing E. coli fimbrial subunit proteins have the potential to vaccinate against these diseases, but have not reached their full potential as a renewable source of oral vaccines due in part to insufficient levels of recombinant protein accumulation. Previously, we reported that cytosol targeting of the E. coli K99 fimbrial subunit antigen resulted in FanC accumulation to approximately 0.4% of total soluble protein in soybean leaves (Piller et al. in Planta 222:6-18, 2005). In this study, we report on the subcellular targeting of FanC to chloroplasts. Twenty-two transgenic T1 progeny derived from seven individual T0 transformation events were characterized, and 17 accumulated transgenic FanC. All of the characterized events displayed relatively low T-DNA complexity, and all exhibited proper targeting of FanC to the chloroplast. Accumulation of chloroplast-targeted FanC was approximately 0.08% of total soluble leaf protein, or approximately 5-fold less than cytosol-targeted FanC. Protein analysis of leaves at various stages of maturity suggested stability of chloroplast-targeted FanC throughout leaf maturation. Furthermore, mice immunized intraperitoneally with protein extract derived from transgenic leaves expressing chloroplast-targeted FanC developed significant antibody titers against FanC. This is the first report of subcellular targeting of a vaccine subunit antigen in soybean.

Morphology and growth pattern of Amazon deep-sea fan: a computer-processed GLORIA side-scan mosaic

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

Flood, R.D.; Damuth, J.E.

1984-04-01

Deep-sea fans have become increasingly important targets for exploration because of their favorable facies associations. A better understanding of deep-sea fans is needed to successfully exploit these complex sediment bodies. Recent studies of the Amazon fan, using long-range side-scan sonar (GLORIA) and single-channel seismic data, provide an overall view of channel patterns of this fan and demonstrate the relationship between successive channel/levee systems. The digitally collected GLORIA data have been computer processed to produce a mosaic of the fan. Computer processing has corrected the records for slant range and ship navigation, and targets have been enhanced. Many features of themore » modern fan system are readily apparent on the sonar mosaic. The 1.5 to 0.5-km (5000 to 1600-ft) wide channels meander intensely across the fan with sinuosities up to 2.5. Because of these meanders, the channel gradients decrease regularly across the fan despite changes in regional slope. Other channel-related targets include cutoff meanders, overbank deposits (especially small debris flows), and channel branchings. Other debris flows cover large areas of the fan and override channel/levee systems. Air-gun records show that this fan is built of a series of channel/levee systems that overlay one another. Channels from at least 6 of these systems are visible at the surface now, but apparently only one channel at a time has been active. The length of time needed to build a single channel/levee system is not known, but it appears to be rapid.« less

A multiple-fan active control wind tunnel for outdoor wind speed and direction simulation

NASA Astrophysics Data System (ADS)

Wang, Jia-Ying; Meng, Qing-Hao; Luo, Bing; Zeng, Ming

2018-03-01

This article presents a new type of active controlled multiple-fan wind tunnel. The wind tunnel consists of swivel plates and arrays of direct current fans, and the rotation speed of each fan and the shaft angle of each swivel plate can be controlled independently for simulating different kinds of outdoor wind fields. To measure the similarity between the simulated wind field and the outdoor wind field, wind speed and direction time series of two kinds of wind fields are recorded by nine two-dimensional ultrasonic anemometers, and then statistical properties of the wind signals in different time scales are analyzed based on the empirical mode decomposition. In addition, the complexity of wind speed and direction time series is also investigated using multiscale entropy and multivariate multiscale entropy. Results suggest that the simulated wind field in the multiple-fan wind tunnel has a high degree of similarity with the outdoor wind field.

Development of monitoring and control system for a mine main fan based on frequency converter

NASA Astrophysics Data System (ADS)

Zhang, Y. C.; Zhang, R. W.; Kong, X. Z.; Y Gong, J.; Chen, Q. G.

2013-12-01

In the process of mine exploitation, the requirement of air flow rate often changes. The procedure of traditional control mode of the fan is complex and it is hard to meet the worksite requirement for air. This system is based on Principal Computer (PC) monitoring system and high performance PLC control system. In this system, the frequency converter is adapted to adjust the fan speed and the air of worksite can be regulated steplessly. The function of the monitoring and control system contains on-line monitoring and centralized control. The system can monitor the parameters of fan in real-time, control the operation of frequency converter, as well as, control the fan and its accessory equipments. At the same time, the automation level of the system is highly, the field equipments can be monitored and controlled automatically. So, the system is an important safeguard for mine production.

Numerical simulation of tonal fan noise of computers and air conditioning systems

NASA Astrophysics Data System (ADS)

Aksenov, A. A.; Gavrilyuk, V. N.; Timushev, S. F.

2016-07-01

Current approaches to fan noise simulation are mainly based on the Lighthill equation and socalled aeroacoustic analogy, which are also based on the transformed Lighthill equation, such as the wellknown FW-H equation or the Kirchhoff theorem. A disadvantage of such methods leading to significant modeling errors is associated with incorrect solution of the decomposition problem, i.e., separation of acoustic and vortex (pseudosound) modes in the area of the oscillation source. In this paper, we propose a method for tonal noise simulation based on the mesh solution of the Helmholtz equation for the Fourier transform of pressure perturbation with boundary conditions in the form of the complex impedance. A noise source is placed on the surface surrounding each fan rotor. The acoustic fan power is determined by the acoustic-vortex method, which ensures more accurate decomposition and determination of the pressure pulsation amplitudes in the near field of the fan.

Decoding sediment transport dynamics on alluvial fans from spatial changes in grain size, Death Valley, California

NASA Astrophysics Data System (ADS)

Brooke, Sam; Whittaker, Alexander; Watkins, Stephen; Armitage, John

2017-04-01

How fluvial sediment transport processes are transmitted to the sedimentary record remains a complex problem for the interpretation of fluvial stratigraphy. Alluvial fans represent the condensed sedimentary archive of upstream fluvial processes, controlled by the interplay between tectonics and climate over time, infused with the complex signal of internal autogenic processes. With high sedimentation rates and near complete preservation, alluvial fans present a unique opportunity to tackle the problem of landscape sensitivity to external boundary conditions such as climate. For three coupled catchments-fan systems in the tectonically well-constrained northern Death Valley, we measure grain size trends across well-preserved Holocene and Late-Pleistocene deposits, which we have mapped in detail. Our results show that fan surfaces from the Late-Pleistocene are, on average, 50% coarser than counterpart active or Holocene fan surfaces, with clear variations in input grain sizes observed between surfaces of differing age. Furthermore, the change in ratio between mean grain size and standard deviation is stable downstream for all surfaces, satisfying the statistical definition of self-similarity. Applying a self-similarity model of selective deposition, we derive a relative mobility function directly from our grain size distributions, and we evaluate for each fan surface the grain size for which the ratio of the probability of transport to deposition is 1. We show that the "equally mobile" grain size lies in the range of 20 to 35 mm, varies over time, and is clearly lower in the Holocene than in the Pleistocene. Our results indicate that coarser grain sizes on alluvial fans are much less mobile than in river systems where such an analysis has been previously applied. These results support recent findings that alluvial fan sediment characteristics can be used as an archive of past environmental change and that landscapes are sensitive to environmental change over a glacial-interglacial cycle. Significantly, the self-similarity methodology offers a means to constrain relative mobility of grain sizes from field measurements where hydrological information is lost or irretrievable.

Study on dynamic multi-objective approach considering coal and water conflict in large scale coal group

NASA Astrophysics Data System (ADS)

Feng, Qing; Lu, Li

2018-01-01

In the process of coal mining, destruction and pollution of groundwater in has reached an imminent time, and groundwater is not only related to the ecological environment, but also affect the health of human life. Similarly, coal and water conflict is still one of the world's problems in large scale coal mining regions. Based on this, this paper presents a dynamic multi-objective optimization model to deal with the conflict of the coal and water in the coal group with multiple subordinate collieries and arrive at a comprehensive arrangement to achieve environmentally friendly coal mining strategy. Through calculation, this paper draws the output of each subordinate coal mine. And on this basis, we continue to adjust the environmental protection parameters to compare the coal production at different collieries at different stages under different attitude of the government. At last, the paper conclude that, in either case, it is the first arrangement to give priority to the production of low-drainage, high-yield coal mines.

Quantifying sediment connectivity in an actively eroding gully complex, Waipaoa catchment, New Zealand

NASA Astrophysics Data System (ADS)

Taylor, Richard J.; Massey, Chris; Fuller, Ian C.; Marden, Mike; Archibald, Garth; Ries, William

2018-04-01

Using a combination of airborne LiDAR (2005) and terrestrial laser scanning (2007, 2008, 2010, 2011), sediment delivery processes and sediment connectivity in an 20-ha gully complex, which significantly contributes to the Waipaoa sediment cascade, are quantified over a 6-year period. The acquisition of terrain data from high-resolution surveys of the whole gully-fan system provides new insights into slope processes and slope-channel linkages operating in the complex. Raw terrain data from the airborne and ground-based laser scans were converted into raster DEMs with a vertical accuracy between surveys of <±0.1 m. Grid elevations in each successive DEM were subtracted from the previous DEM to provide models of change across the gully and fan complex. In these models deposition equates to positive and erosion to negative vertical change. Debris flows, slumping, and erosion by surface runoff (gullying in the conventional sense) generated on average 95,232 m3 of sediment annually, with a standard deviation of ± 20,806 m3. The volumes of debris eroded from those areas dominated by surface erosion processes were higher than in areas dominated by landslide processes. Over the six-year study period, sediment delivery from the source zones to the fan was a factor of 1.4 times larger than the volume of debris exported from the fan into Te Weraroa Stream. The average annual volume of sediment exported to Te Weraroa Stream varies widely from 23,195 to 102,796 m3. Fluctuations in the volume of stored sediment within the fan, rather than external forcing by rainstorms or earthquakes, account for this annual variation. No large rainfall events occurred during the monitoring period; therefore, sediment volumes and transfer processes captured by this study are representative of the background conditions that operate in this geomorphic system.

Differential Roles of the Fan-Shaped Body and the Ellipsoid Body in "Drosophila" Visual Pattern Memory

ERIC Educational Resources Information Center

Pan, Yufeng; Zhou, Yanqiong; Guo, Chao; Gong, Haiyun; Gong, Zhefeng; Liu, Li

2009-01-01

The central complex is a prominent structure in the "Drosophila" brain. Visual learning experiments in the flight simulator, with flies with genetically altered brains, revealed that two groups of horizontal neurons in one of its substructures, the fan-shaped body, were required for "Drosophila" visual pattern memory. However,…

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).

Supercritical flows and their control on the architecture and facies of small-radius sand-rich fan lobes

NASA Astrophysics Data System (ADS)

Postma, George; Kleverlaan, Kick

2018-02-01

New insights into flow characteristics of supercritical, high-density turbidity currents initiated renewed interest in a sand-rich lobe complex near the hamlet of Mizala in the Sorbas Basin (Tortonian, SE Spain). The field study was done using drone-made images taken along bed strike in combination with physical tracing of bounding surfaces and section logging. The studied lobe systems show a consistent built-up of lobe elements of 1.5-2.0 m thick, which form the building 'blocks' of the lobe system. The stacking of lobe elements shows lateral shift and compensational relief infill. The new model outlined in this paper highlights three stages of fan lobe development: I. an early aggradational stage with lobe elements characterized by antidune and traction-carpet bedforms and burrowed mud intervals (here called 'distal fan' deposits); II. a progradational stage, where the distal fan deposits are truncated by lobe elements of amalgamated sandy to gravelly units characterized by cyclic step bedform facies (designated as 'supra fan' deposits). The supra fan is much more channelized and scoured and of higher flow energy than the distal-fan. Aggradation of the supra-fan is terminated by a 'pappy' pebbly sandstone and by substrate liquefaction, 'pappy' referring to a typical, porridge-like texture indicating rapid deposition under conditions of little-to-no shear. The facies-bounded termination of the supra-fan is here related to its maximum elevation, causing the lobe-feeding supercritical flow to choke and to expand upwards by a strong hydraulic jump at the channel outlet; III. a backfilling stage, characterized by backfilling of the remaining relief with progressively thinning and fining of turbidite beds and eventually with mud. The three-stage development for fan-lobe building is deducted from reoccurring architectural and facies characteristics in three successive fan-lobes. The validity of using experimental, supercritical-flow fan studies for understanding the intrinsic mechanisms in sand-rich-fan lobe development is discussed.

Technical Assessment of the National Full Scale Aerodynamic Complex Fan Blades Repair

NASA Technical Reports Server (NTRS)

Young, Clarence P., Jr.; Dixon, Peter G.; St.Clair, Terry L.; Johns, William E.

1998-01-01

This report describes the principal activities of a technical review team formed to address National Full Scale Aerodynamic Complex (NFAC) blade repair problems. In particular, the problem of lack of good adhesive bonding of the composite overwrap to the Hyduliginum wood blade material was studied extensively. Description of action plans and technical elements of the plans are provided. Results of experiments designed to optimize the bonding process and bonding strengths obtained on a full scale blade using a two-step cure process with adhesive primers are presented. Consensus recommendations developed by the review team in conjunction with the NASA Ames Fan Blade Repair Project Team are provided along with lessons learned on this program. Implementation of recommendations resulted in achieving good adhesive bonds between the composite materials and wooden blades, thereby providing assurance that the repaired fan blades will meet or exceed operational life requirements.

Impact of Conflict Management Strategies on the Generation Mechanism of Miners' Unsafe Behavior Tendency

ERIC Educational Resources Information Center

Li, Ji-Zu; Zhang, Ya-Ping; Liu, Xiao-Guang; Liu, Yao-Long; Wang, Tian-Ri

2017-01-01

In this paper, we examine the relationship between the generation mechanism of miners' unsafe behavior tendency and conflict management strategies, including cooperative conflict management strategy, competitive conflict management strategy and avoidant conflict management strategy. Miners from 3 collieries in Shanxi province completed a…

Late Quaternary alluvial fans of Emli Valley in the Ecemiş Fault Zone, south central Turkey: Insights from cosmogenic nuclides

NASA Astrophysics Data System (ADS)

Akif Sarıkaya, M.; Yıldırım, Cengiz; Çiner, Attila

2015-01-01

Alluvial fans within the paraglacial Ecemiş River drainages on the Aladağlar Mountains in south central Turkey were studied using geomorphological, sedimentological, and chlorine-36 terrestrial cosmogenic nuclide (TCN) surface exposure dating methods to examine the timing of alluvial fan abandonment/incision, and to understand the role of climatic and tectonic processes in the region. These alluvial fan complexes are among the best-preserved succession of alluvial fans in Turkey and they were offset by the major strike-slip Ecemiş Fault of the Central Anatolian Fault Zone. The alluvial fans are mostly composed of well-lithified limestone cobbles (5 to 25 cm in size), and comprise crudely stratified thick beds with a total thickness reaching up to about 80 m. TCN surface exposure dating indicates that the oldest alluvial fan surface (Yalak Fan) was likely formed and subsequently abandoned latest by 136.0 ± 23.4 ka ago, largely on the transition of the Penultimate Glaciation (Marine Isotope Stage 6, MIS 6) to the Last Interglacial (MIS 5) (i.e. Termination II). The second set of alluvial fan (Emli Fan) was possibly developed during the Last Interglacial (MIS 5), and incised twice by between roughly 97.0 ± 13.8 and 81.2 ± 13.2 ka ago. A younger alluvial fan deposit placed on relatively older erosional terraces of the Emli Fan suggests that it may have been produced during the Last Glacial Cycle (MIS 2). These events are similar to findings from other fluvial and lacustrine deposits throughout central Anatolia. The incision times of the Ecemiş alluvial fan surfaces largely coincide with major climatic shifts from the cooler glacial periods to warmer interglacial/interstadial conditions. This indicates that alluvial fans were produced by outwash sediments of paleoglaciers during cooler conditions, and, later, when glaciers started to retreat due to a major warming event, the excess water released from the glaciers incised the pre-existing fan surfaces. An alluvial fan in the study area was also cut by the Ecemiş Fault, highlighting the influence of tectonics on fan development. It was offset vertically 35 ± 3 m since at least 97.0 ± 13.8 ka, which suggests a 0.36 ± 0.06 mm a- 1 vertical slip-rate of the fault.

Bioactivity of 2′-deoxyinosine-incorporated aptamer AS1411

PubMed Central

Fan, Xinmeng; Sun, Lidan; Wu, Yun; Zhang, Lihe; Yang, Zhenjun

2016-01-01

Aptamers can be chemically modified to enhance nuclease resistance and increase target affinity. In this study, we performed chemical modification of 2′-deoxyinosine in AS1411, an anti-proliferative G-rich oligodeoxynucleotide aptamer, which binds selectively to the nucleolin protein. Its function was augmented when 2′-deoxyinosine was incorporated at positions 12, 13, 15, and 24 of AS1411, respectively. In addition, double incorporation of 2′-deoxyinosine at positions 12 and 24 (FAN-1224dI), 13 and 24 (FAN-1324dI), and 15 and 24 (FAN-1524dI) promoted G-quartet formation, as well as inhibition of DNA replication and tumor cell growth, and induced S-phase cell cycle arrest. In further animal experiments, FAN-1224dI, FAN-1324dI and FAN-1524dI resulted in enhanced treatment effects than AS1411 alone. These results suggested that the position and number of modification substituents in AS1411 are critical parameters to improve the diagnostic and therapeutic function of the aptamer. Structural investigations of the FAN-1524dI/nucleolin complex structure, using molecular dynamics simulation, revealed the critical interactions involving nucleolin and 2′-dI incorporated AS1411 compared with AS1411 alone. These findings augment understanding of the role of 2′-deoxyinosine moieties in interactive binding processes. PMID:27194215

Bioactivity of 2'-deoxyinosine-incorporated aptamer AS1411.

PubMed

Fan, Xinmeng; Sun, Lidan; Wu, Yun; Zhang, Lihe; Yang, Zhenjun

2016-05-19

Aptamers can be chemically modified to enhance nuclease resistance and increase target affinity. In this study, we performed chemical modification of 2'-deoxyinosine in AS1411, an anti-proliferative G-rich oligodeoxynucleotide aptamer, which binds selectively to the nucleolin protein. Its function was augmented when 2'-deoxyinosine was incorporated at positions 12, 13, 15, and 24 of AS1411, respectively. In addition, double incorporation of 2'-deoxyinosine at positions 12 and 24 (FAN-1224dI), 13 and 24 (FAN-1324dI), and 15 and 24 (FAN-1524dI) promoted G-quartet formation, as well as inhibition of DNA replication and tumor cell growth, and induced S-phase cell cycle arrest. In further animal experiments, FAN-1224dI, FAN-1324dI and FAN-1524dI resulted in enhanced treatment effects than AS1411 alone. These results suggested that the position and number of modification substituents in AS1411 are critical parameters to improve the diagnostic and therapeutic function of the aptamer. Structural investigations of the FAN-1524dI/nucleolin complex structure, using molecular dynamics simulation, revealed the critical interactions involving nucleolin and 2'-dI incorporated AS1411 compared with AS1411 alone. These findings augment understanding of the role of 2'-deoxyinosine moieties in interactive binding processes.

Statistic inversion of multi-zone transition probability models for aquifer characterization in alluvial fans

DOE PAGES

Zhu, Lin; Dai, Zhenxue; Gong, Huili; ...

2015-06-12

Understanding the heterogeneity arising from the complex architecture of sedimentary sequences in alluvial fans is challenging. This study develops a statistical inverse framework in a multi-zone transition probability approach for characterizing the heterogeneity in alluvial fans. An analytical solution of the transition probability matrix is used to define the statistical relationships among different hydrofacies and their mean lengths, integral scales, and volumetric proportions. A statistical inversion is conducted to identify the multi-zone transition probability models and estimate the optimal statistical parameters using the modified Gauss–Newton–Levenberg–Marquardt method. The Jacobian matrix is computed by the sensitivity equation method, which results in anmore » accurate inverse solution with quantification of parameter uncertainty. We use the Chaobai River alluvial fan in the Beijing Plain, China, as an example for elucidating the methodology of alluvial fan characterization. The alluvial fan is divided into three sediment zones. In each zone, the explicit mathematical formulations of the transition probability models are constructed with optimized different integral scales and volumetric proportions. The hydrofacies distributions in the three zones are simulated sequentially by the multi-zone transition probability-based indicator simulations. Finally, the result of this study provides the heterogeneous structure of the alluvial fan for further study of flow and transport simulations.« less

Active sources in the cutoff of centrifugal fans to reduce the blade tones at higher-order duct mode frequencies

NASA Astrophysics Data System (ADS)

Neise, W.; Koopmann, G. H.

1991-01-01

A previously developed (e.g., Neise and Koopmann, 1984; Koopmann et al., 1988) active noise control technique in which the unwanted acoustic signals from centrifugal fans are suppressed by placing two externally driven sources near the cutoff of the casing was applied to the frequency region where not only plane sound waves are propagational in the fan ducts but also higher-order acoustic modes. Using a specially designed fan noise testing facility, the performance of two fans (280-mm impeller diam and 508 mm diam) was monitored with static pressure taps mounted peripherally around the inlet nozzle. Experimental results show that the aerodynamically generated source pressure field around the cutoff is too complex to be successfully counterimaged by only two active sources introduced in this region. It is suggested that, for an efficient application of this noise control technique in the higher-order mode frequency regime, it is neccessary to use an active source involving larger number of individually driven loudspeakers.

Failure Maps for Rectangular 17-4PH Stainless Steel Sandwiched Foam Panels

NASA Technical Reports Server (NTRS)

Raj, S. V.; Ghosn, L. J.

2007-01-01

A new and innovative concept is proposed for designing lightweight fan blades for aircraft engines using commercially available 17-4PH precipitation hardened stainless steel. Rotating fan blades in aircraft engines experience a complex loading state consisting of combinations of centrifugal, distributed pressure and torsional loads. Theoretical failure plastic collapse maps, showing plots of the foam relative density versus face sheet thickness, t, normalized by the fan blade span length, L, have been generated for rectangular 17-4PH sandwiched foam panels under these three loading modes assuming three failure plastic collapse modes. These maps show that the 17-4PH sandwiched foam panels can fail by either the yielding of the face sheets, yielding of the foam core or wrinkling of the face sheets depending on foam relative density, the magnitude of t/L and the loading mode. The design envelop of a generic fan blade is superimposed on the maps to provide valuable insights on the probable failure modes in a sandwiched foam fan blade.

Enhancing flood hazard estimation methods on alluvial fans using an integrated hydraulic, geological and geomorphological approach

NASA Astrophysics Data System (ADS)

Mollaei, Zeinab; Davary, Kamran; Majid Hasheminia, Seyed; Faridhosseini, Alireza; Pourmohamad, Yavar

2018-04-01

Due to the uncertainty concerning the location of flow paths on active alluvial fans, alluvial fan floods could be more dangerous than riverine floods. The United States Federal Emergency Management Agency (FEMA) used a simple stochastic model named FAN for this purpose, which has been practiced for many years. In the last decade, this model has been criticized as a consequence of development of more complex computer models. This study was conducted on three alluvial fans located in northeast and southeast Iran using a combination of the FAN model, the hydraulic portion of the FLO-2D model, and geomorphological information. Initial stages included three steps: (a) identifying the alluvial fans' landforms, (b) determining the active and inactive areas of alluvial fans, and (c) delineating 100-year flood within these selected areas. This information was used as an input in the mentioned three approaches of the (i) FLO-2D model, (ii) geomorphological method, and (iii) FAN model. Thereafter, the results of each model were obtained and geographical information system (GIS) layers were created and overlaid. Afterwards, using a scoring system, the results were evaluated and compared. The goal of this research was to introduce a simple but effective solution to estimate the flood hazards. It was concluded that the integrated method proposed in this study is superior at projecting alluvial fan flood hazards with minimum required input data, simplicity, and affordability, which are considered the primary goals of such comprehensive studies. These advantages are more highlighted in underdeveloped and developing countries, which may well lack detailed data and financially cannot support such costly projects. Furthermore, such a highly cost-effective method could be greatly advantageous and pragmatic for developed countries.

Late Cretaceous and Paleogene sedimentation along east side of San Joaquin basin, California

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

Reid, S.A.

1986-04-01

Depositional systems of the Late Cretaceous contrast with those of the Paleogene in the subsurface along the east side of the San Joaquin basin between Bakersfield and Fresno, California. Upper Cretaceous deposits include thick fan-delta and submarine fan facies of the Moreno and Panoche Formations, whereas the paleogene contains extensive nearshore, shelf, slope, and submarine fan deposits of the Lodo, Domengine, and Kreyenhagen Formations. These sediments were deposited on a basement surface having several west-trending ridges and valleys. West-flowing streams draining an ancestral Sierra Nevada of moderate relief formed prograding fan deltas that filled the valleys with thick wedges ofmore » nonmarine channel deposits, creating a bajada along the shoreline. Detrital material moved rapidly from the shoreline through a narrow shelf, into a complex of submarine fans in the subduction trough. During the early Eocene, a low sea level stand plus an end of Sierra Nevada uplift resulted in the erosion of the range to a peneplain. Stream-fed fan deltas were replaced by a major river system, which flowed west on about the present course of the Kern River. Following a rapid sea level increase, sand from the river system was deposited on the now broad shelf along a wide belt roughly coincident with California Highway 99. The river was also the point source for sand in a submarine fan northwest of Bakersfield. Both Upper Cretaceous and Paleogene depositional systems probably continue north along the east edge of the Great Valley. This proposed scenario for the east side of the San Joaquin is analogous to forearc deposits in the San Diego area, including the Cretaceous Rosario fan-delta and submarine fan system and the Eocene La Jolla and Poway nearshore, shelf, and submarine fan systems.« less

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

Zhu, Lin; Dai, Zhenxue; Gong, Huili

Understanding the heterogeneity arising from the complex architecture of sedimentary sequences in alluvial fans is challenging. This study develops a statistical inverse framework in a multi-zone transition probability approach for characterizing the heterogeneity in alluvial fans. An analytical solution of the transition probability matrix is used to define the statistical relationships among different hydrofacies and their mean lengths, integral scales, and volumetric proportions. A statistical inversion is conducted to identify the multi-zone transition probability models and estimate the optimal statistical parameters using the modified Gauss–Newton–Levenberg–Marquardt method. The Jacobian matrix is computed by the sensitivity equation method, which results in anmore » accurate inverse solution with quantification of parameter uncertainty. We use the Chaobai River alluvial fan in the Beijing Plain, China, as an example for elucidating the methodology of alluvial fan characterization. The alluvial fan is divided into three sediment zones. In each zone, the explicit mathematical formulations of the transition probability models are constructed with optimized different integral scales and volumetric proportions. The hydrofacies distributions in the three zones are simulated sequentially by the multi-zone transition probability-based indicator simulations. Finally, the result of this study provides the heterogeneous structure of the alluvial fan for further study of flow and transport simulations.« less

Response of Cenozoic turbidite system to tectonic activity and sea-level change off the Zambezi Delta

NASA Astrophysics Data System (ADS)

Castelino, Jude A.; Reichert, Christian; Jokat, Wilfried

2017-09-01

Submarine fans and turbidite systems are important and sensitive features located offshore from river deltas that archive tectonic events, regional climate, sea level variations and erosional process. Very little is known about the sedimentary structure of the 1800 km long and 400 km wide Mozambique Fan, which is fed by the Zambezi and spreads out into the Mozambique Channel. New multichannel seismic profiles in the Mozambique Basin reveal multiple feeder systems of the upper fan that have been active concurrently or consecutively since Late Cretaceous. We identify two buried, ancient turbidite systems off Mozambique in addition to the previously known Zambezi-Channel system and another hypothesized active system. The oldest part of the upper fan, located north of the present-day mouth of the Zambezi, was active from Late Cretaceous to Eocene times. Regional uplift caused an increased sediment flux that continued until Eocene times, allowing the fan to migrate southwards under the influence of bottom currents. Following the mid-Oligocene marine regression, the Beira High Channel-levee complex fed the Mozambique Fan from the southwest until Miocene times, reworking sediments from the shelf and continental slope into the distal abyssal fan. Since the Miocene, sediments have bypassed the shelf and upper fan region through the Zambezi Valley system directly into the Zambezi Channel. The morphology of the turbidite system off Mozambique is strongly linked to onshore tectonic events and the variations in sea level and sediment flux.

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 strongly dependent on substrate thickness and basin slope directly influences channel geometry. These findings will also be compared to the Mojave River Wash located in southern California off the San Bernardino Mountains near Zzyzx, CA to further understand the dynamics of terminal fans on a mobile substrate.

Experimental investigation into the impact of vegetation on fan morphology and flow

NASA Astrophysics Data System (ADS)

Clarke, Lucy; McLelland, Stuart; Coulthard, Tom

2013-04-01

Riparian vegetation can significantly influence the geomorphology of fluvial systems, affecting channel geometry and flow dynamics. However, there is still limited understanding of the role vegetation plays in the development of alluvial fans, despite the large number of vegetated fans located in temperate and humid climates. An understanding of the feedback loops between water flow, sediment dynamics and vegetation is key to understanding the geomorphological response of alluvial fans. But it is difficult to investigate these relationships in the natural world due to the complexity of the geomorphic and biological processes and timescales involved. To examine the effects of vegetation on channel form, flow dynamics and morphology during fan evolution, a series of experiments were conducted using the Total Environment Simulator at the Deep, an experimental facility operated by the University of Hull. The experiments followed a 'similarity of processes' approach and so were not scaled to a specific field prototype. Live vegetation (alfalfa) was used to simulate the influence of vegetation on the fan development. A range of experiments were conducted on fan plots 2x2m in size, the same initial conditions and constant water discharge and sediment feed rates were used, but the vegetation density and amount of geomorphic time (when the sediment and water were running and there was active fan development) between seeding / vegetation growth varied between runs. The fan morphology was recorded at regular intervals using a laser scanner (at 1mm resolution) and high resolution video recording and overhead photography was also used to gain near-continuous data quantifying fan topography, flow patterns, channel migration and avulsion frequency. Image analysis also monitored the spatial extent of vegetation establishment. The use of these techniques allowed collection of high resolution spatial and temporal data on fan development with minimal disruption to the experiments. The results of the preliminary experiments showed that vegetation did influence the morphology and flow conditions during fan evolution. Vegetation reduced the number of active channels, and increasing the vegetation density also led to lower lateral migration rates, the formation of narrower and deeper channels and an increase in fan slope.

Tracking Adjustments in Fan and Floodplain Storage in a Braided Channel following Major Sedimentary Disturbance, East Cape, NZ

NASA Astrophysics Data System (ADS)

Tunnicliffe, J. F.; Leenman, A.; Eaton, B. C.; Fuller, I. C.

2016-12-01

In this paper we reconstruct the trajectory of a coarse-grained gravel-bed network in recovery from a major sedimentary disturbance, driven by mass-wasting during and following ex-tropical Cyclone Bola in 1988. A strong trend of aggradation in the Tapuaeroa Catchment between 1988 and 2004 culminated in a valley fill with a thickness of up to 35 m. A record of cross-section surveys spanning 40 years, and high resolution structure-from-motion surveys spanning 2015-2016, shows the complex nature of recovery; the upper tributary sections exhibit incision and terrace-building while the lower reaches and the trunk channel exhibit a mix of aggradation and degradation. Tributary fans provide a record of changes to intermediate storage, depending on local supply conditions in the trunk channel. A sediment budget model is developed to elucidate the complex nature of fan and floodplain evolution over decadal timescales following a major disturbance.

Altitude Wind Tunnel Drive Fan being Assembled

NASA Image and Video Library

1943-07-21

National Advisory Committee for Aeronautics (NACA) engineers assembled the Altitude Wind Tunnel’s (AWT) large wooden drive fan inside the hangar at the Aircraft Engine Research Laboratory. When it was built at the in the early 1940s the AWT was among the most complex test facilities ever designed. It was the first wind tunnel capable of operating full-scale engines under realistic flight conditions. This simulation included the reduction of air temperature, a decrease in air pressure, and the creation of an airstream velocity of up to 500 miles per hour. The AWT was constructed in 1942 and 1943. This photograph shows NACA engineers Lou Hermann and Jack Aust assembling the tunnel’s drive fan inside the hangar. The 12-bladed, 31-foot-diameter spruce wood fan would soon be installed inside the wind tunnel to create the high-speed airflow. This massive propeller was designed and constructed by the engine lab's design team at Langley Field. John Breisch, a Langley technician with several years of wind tunnel installation experience, arrived in Cleveland at the time of this photograph to supervise the fan assembly inside the hangar. He would return several weeks later to oversee the actual installation in the tunnel. The fan was driven at 410 revolutions per minute by an 18,000-horsepower General Electric induction motor that was located in the rear corner of the Exhauster Building. An extension shaft connected the motor to the fan. A bronze screen protected the fan against damage from failed engine parts sailing through the tunnel. Despite this screen the blades did become worn or cracked over time and had to be replaced. An entire new fan was installed in 1951.

GPR-derived architecture of a lahar-generated fan at Cotopaxi volcano, Ecuador

NASA Astrophysics Data System (ADS)

Ettinger, Susanne; Manville, Vern; Kruse, Sarah; Paris, Raphaël

2014-05-01

The internal geometry of volcaniclastic fans produced by aggradation during lahar events is difficult to examine in modern settings because of the frequent lack of three-dimensional exposures. This makes it challenging to (i) reconstruct the spatial and temporal evolution of such fans; and (ii) interpret observed facies stratigraphy in the context of lahar flow dynamics from proximal to distal fan reaches. This research therefore presents the results of a ground penetrating radar (GPR) survey of the Rumipamba fan at the mouth of the Burrohuaycu quebrada on the southwestern flank of Cotopaxi volcano. A survey grid consisting of 50 individual GPR profiles representing a total length of 19.4 km was constructed covering most of the 4-km2 large fan surface. All GPR profiles were collected using a PulseEKKO 100 with a 400 V transmitter. Fan sediments consist of sandy and gravelly lahar deposits, alternating with volcanic fallout including ash and pumice lapilli, at times reworked by fluvial processes. Deposits could be ground-truthed to a depth of ~3 m, whereas GPR penetration depth reaches 15 m. Data interpretation was based on classification into 15 distinct radar facies characterized by the nature of their bounding surfaces and/or internal features, cross-referenced where possible with shallow exposures. Three main facies were identified: parallel, irregular, and clinoform. Erosional contacts were distinguished from aggradational ones (vertical, channel fill, and lateral accretion). Flow parallel versus flow transverse and proximal-distal variations in deposit architecture were featured. The results of this study confirm the existence of two major channel systems in the northern and southern extremities of the fan and the more recent formation of a smaller central fan channel system. Deposit architecture is complex and facies chronologies illustrate that lahars have affected the entire survey area.

Sedimentary Facies of the West Crocker Formation North Kota Kinabalu-Tuaran Area, Sabah, Malaysia

NASA Astrophysics Data System (ADS)

Mohamed, Azfar; Hadi Abd Rahman, Abdul; Suhaili Ismail, Mohd

2016-02-01

Newly outcrops exposed in the West Crocker Formation have led to the detail sedimentolgical analysis of the formation. Eight sedimentary facies have been recognised in which it was divided into three main groups: (1) sand-dominated facies (F1-F2), (2) poorly- sorted unit mixed sand and mud-dominated facies (F3), and (3) mud-dominated facies (F4-F5). These are: F1- graded sandstone (massive to planar laminated), F2-ripple-cross laminated, wavy and convolute lamination sandstone, F3-chaotic beds of mixed sandstone and mudstone blocks and clasts, F4-lenticular bedded of sandstone, and F5-shale. The studies of the formation has come out that it was deposited in a sand-rich submarine fan with specific location located at (1) inner fan channel-levee complex; (2) mid-fan channelised lobes, and (3) outer fan.

Modeling of Broadband Liners Applied to the Advanced Noise Control Fan

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, Michael G.; Sutliff, Daniel L.

2015-01-01

The broadband component of fan noise has grown in relevance with an increase in bypass ratio and incorporation of advanced fan designs. Therefore, while the attenuation of fan tones remains a major factor in engine nacelle acoustic liner design, the simultaneous reduction of broadband fan noise levels has received increased interest. As such, a previous investigation focused on improvements to an established broadband acoustic liner optimization process using the Advanced Noise Control Fan (ANCF) rig as a demonstrator. Constant-depth, double-degree of freedom and variable-depth, multi-degree of freedom liner designs were carried through design, fabrication, and testing. This paper addresses a number of areas for further research identified in the initial assessment of the ANCF study. Specifically, incident source specification and uncertainty in some aspects of the predicted liner impedances are addressed. This information is incorporated in updated predictions of the liner performance and comparisons with measurement are greatly improved. Results illustrate the value of the design process in concurrently evaluating the relative costs/benefits of various liner designs. This study also provides further confidence in the integrated use of duct acoustic propagation/radiation and liner modeling tools in the design and evaluation of novel broadband liner concepts for complex engine configurations.

Broadband Liner Optimization for the Source Diagnostic Test Fan

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, Michael G.

2012-01-01

The broadband component of fan noise has grown in relevance with the utilization of increased bypass ratio and advanced fan designs. Thus, while the attenuation of fan tones remains paramount, the ability to simultaneously reduce broadband fan noise levels has become more appealing. This paper describes a broadband acoustic liner optimization study for the scale model Source Diagnostic Test fan. Specifically, in-duct attenuation predictions with a statistical fan source model are used to obtain optimum impedance spectra over a number of flow conditions for three liner locations in the bypass duct. The predicted optimum impedance information is then used with acoustic liner modeling tools to design liners aimed at producing impedance spectra that most closely match the predicted optimum values. Design selection is based on an acceptance criterion that provides the ability to apply increased weighting to specific frequencies and/or operating conditions. Typical tonal liner designs targeting single frequencies at one operating condition are first produced to provide baseline performance information. These are followed by multiple broadband design approaches culminating in a broadband liner targeting the full range of frequencies and operating conditions. The broadband liner is found to satisfy the optimum impedance objectives much better than the tonal liner designs. In addition, the broadband liner is found to provide better attenuation than the tonal designs over the full range of frequencies and operating conditions considered. Thus, the current study successfully establishes a process for the initial design and evaluation of novel broadband liner concepts for complex engine configurations.

A Pleistocene coastal alluvial fan complex produced by Middle Pleistocene glacio-fluvial processes

NASA Astrophysics Data System (ADS)

Adamson, Kathryn; Woodward, Jamie; Hughes, Philip; Giglio, Federico; Del Bianco, Fabrizio

2014-05-01

A coarse-grained alluvial fan sequence at Lipci, Kotor Bay, in western Montenegro, provides a sedimentary record of meltwater streams draining from the Orjen Massif (1,894 m a.s.l.) to the coastal zone. At Lipci sedimentary evidence and U-series ages have been used alongside offshore bathymetric imagery and seismic profiles to establish the size of the fan and constrain the nature and timing of its formation. Establishing the depositional history of such coastal fans is important for our understanding of cold stage sediment flux from glaciated uplands to the offshore zone, and for exploring the impact of sea level change on fan reworking. There is evidence of at least four phases of Pleistocene glaciation on the Orjen massif, which have been U-series dated and correlated to MIS 12, MIS 6, MIS 5d-2 and the Younger Dryas. A series of meltwater channels delivered large volumes of coarse- and fine-grained limestone sediment from the glaciated uplands into the Bay of Kotor. At the southern margin of the Orjen massif, a series of large (>700 m long) alluvial fans has developed. Some of these extend offshore for up to 600 m. Lipci fan lies downstream of end moraines in the valley immediately above, which were formed by an extensive outlet glacier of the Orjen ice cap during MIS 12. The terrestrial deposits are part of the fan apex (50 m a.s.l.) that lies at the foot of a steep bedrock channel, but the majority of the fan is now more than 25 m below sea level. The terrestrial fan sediments are strongly cemented by multiple generations of calcite precipitates: the oldest U-series ages are infinite indicating that the fan is >350 ka in age. These ages are in agreement with alluvial sedimentary evidence and U-series ages from other fluvial units on Mount Orjen. The terrestrial portion of the Lipci fan surface contains several channels. These are well preserved due to cementation with calcium carbonate. Submarine imagery indicates that the now submerged portion of the fan also contains deeply incised (up to 10 m) channels which are similar in morphology to those exposed onshore. It is likely that strong cementation of the fan sediments, and associated channel forms, has protected them from coastal erosion during several regression-transgression cycles. These records provide important opportunities to correlate the Pleistocene terrestrial glacial and fluvial records with the marine archive.

Submarine fan facies of Upper Cretaceous Strata, Southern San Rafael Mountains, Santa Barbara County, California

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

Toyne, C.D.

1986-04-01

A 2900-m thick Campanian-Maestrichtian(.) turbidite sequence in Upper Mono Creek Canyon is interpreted to be a progradational submarine fan complex comprised of outer fan, middle fan, inner fan, and slope facies. The basal 600 m of the section consists of thinly bedded, laterally continuous fine sandstones, siltstones, and mudstones (mainly Mutti and Ricci Lucci facies D), interpreted to be outer fan interlobe and lobe-fringe deposits. These are punctuated by infrequent medium to very thickly bedded, flat-based, fine to coarse sandstones (facies C and B), which commonly coarsen and thicken upward, and are interpreted to be depositional lobes. Overlying these depositsmore » are approximately 1400 m of middle fan deposits composed of frequent lenticular, commonly channelized and amalgamated, thickly bedded, fine to very coarse sandstones (facies C and B) organized in fining- and thinning-upward sequences, interpreted to be braided-channel deposits. These alternate with less common nonchannelized coarsening- and thickening-upward sequences suggestive of lobe-apical cycles. These multistory sand deposits are nested within thick intervals of fine sandstones, siltstones, and mudstones (facies C and D), interpreted to be levee, crevasse-splay, and interchannel deposits. Interfingered with and overlying these deposits are approximately 500 m of fining- and thinning-upward or noncyclic, erosionally based, commonly amalgamated, very thickly bedded, medium to very coarse sandstones, pebbly sandstones, and conglomerates (facies A and B), interpreted to be inner fan deposits. Intercalated within this facies, infrequent, laterally discontinuous, thin to thickly bedded, fine to coarse sandstones, siltstones, and mudstones exist, interpreted to be interchannel, levee, and possibly channel-fill deposits.« less

22. Photocopy of photograph. Horgan, November 22, 1920. Negative #D ...

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

22. Photocopy of photograph. Horgan, November 22, 1920. Negative #D & H 20969 Original negative can be found in D & H collection of the Anthracite Heritage Museum, Scranton, Pennsylvania. DETAILED INTERIOR VIEW SHOWING TOP OF JIGS AT TIME OF BREAKER CONSTRUCTION - Marvine Colliery, Breaker No. 2, West side Boulevard Avenue, between East Parker Street & Route 380, Scranton, Lackawanna County, PA

14. Photocopy of photograph. Horgan, 1922. Negative #D & H ...

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

14. Photocopy of photograph. Horgan, 1922. Negative #D & H 22413 Original negative can be found in D & H collection of the Anthracite Heritage Museum, Scranton, Pennsylvania. VIEW SHOWING EAST FACADE OF BREAKER, WITH RETAIL SCALES OFFICE IN FOREGROUND, LOOKING WEST - Marvine Colliery, Breaker No. 2, West side Boulevard Avenue, between East Parker Street & Route 380, Scranton, Lackawanna County, PA

Growth, nitrogen accumulation and nitrogen transfer by legume species established on mine spoils

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

Jefferies, R.A.; Bradshaw, A.D.; Putwain, P.D.

1981-12-01

Nitrogen deficiency is an important factor limiting plant growth on many types of mine and mineral spoils. One method of overcoming this problem is to use legume species which are able to accumulate nitrogen in such spoils. The growth, nitrogen accumulation and nitrogen transfer to a companion species was compared in contrasting legume species established on colliery spoil and on sand waste from the extraction of china clay. Legumes can be effective means of accumulating nitrogen in such spoils with rates as high as 295 kg N ha/sup -1/ yr/sup -1/ being measured for Lupinus perennis sown on sand waste.more » Nitrogen transfer from legumes to a companion grass was also apparent. Trifolium repens sown on colliery spoil increased the nitrogen content of the companion grass by 76 kg ha/sup -1/ within 2 yr of sowing. It is concluded that a wider range of legume species than conventionally used is available, offering greater tolerance of the extreme conditions of mine spoils combined with high rates of nitrogen accumulation. It is necessary to develop reclamation strategies which incorporate such species.« less

Fine-scale relief related to late holocene channel shifting within the floor of the upper Redondo Fan, offshore Southern California

USGS Publications Warehouse

Normark, W.R.; Paull, C.K.; Caress, D.W.; Ussler, W.; Sliter, R.

2009-01-01

Erosional and depositional bedforms have been imaged at outcrop scale in the upper Redondo Fan, in the San Pedro Basin of offshore Southern California in ???600 m water depths, using an Autonomous Underwater Vehicle developed by the Monterey Bay Aquarium Research Institute. The Autonomous Underwater Vehicle is equipped with multibeam and chirp sub-bottom sonars. Sampling and photographic images using the Monterey Bay Aquarium Research Institute Remotely Operated Vehicle Tiburon provide groundtruth for the Autonomous Underwater Vehicle survey. The 0??3 m vertical and 1??5 m lateral bathymetric resolution and 0??1 m sub-bottom profile resolution provide unprecedented detail of bedform morphology and structure. Multiple channels within the Redondo Fan have been active at different times during the Late Holocene (0 to 3000 yr bp). The currently active channel extending from Redondo Canyon makes an abrupt 90?? turn at the canyon mouth before resuming a south-easterly course along the east side of the Redondo Fan. This channel is floored by sand and characterized by small steps generally <1 m in relief, spaced 10 to 80 m in the down-channel direction. A broader channel complex lies along the western side of the fan valley that was last active more than 850 years ago. Two distinct trains of large scours, with widths ranging from tens to a few hundred metres and depths of 20 m, occur on the floor of the western channel complex, which has a thin mud drape. If observed in cross-section only, these large scours would probably be misidentified as the thalweg of an active channel. ?? 2009 The Authors. Journal compilation ?? 2009 International Association of Sedimentologists.

Improved Broadband Liner Optimization Applied to the Advanced Noise Control Fan

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, Michael G.; Sutliff, Daniel L.; Ayle, Earl; Ichihashi, Fumitaka

2014-01-01

The broadband component of fan noise has grown in relevance with the utilization of increased bypass ratio and advanced fan designs. Thus, while the attenuation of fan tones remains paramount, the ability to simultaneously reduce broadband fan noise levels has become more desirable. This paper describes improvements to a previously established broadband acoustic liner optimization process using the Advanced Noise Control Fan rig as a demonstrator. Specifically, in-duct attenuation predictions with a statistical source model are used to obtain optimum impedance spectra over the conditions of interest. The predicted optimum impedance information is then used with acoustic liner modeling tools to design liners aimed at producing impedance spectra that most closely match the predicted optimum values. Design selection is based on an acceptance criterion that provides the ability to apply increased weighting to specific frequencies and/or operating conditions. Constant-depth, double-degree of freedom and variable-depth, multi-degree of freedom designs are carried through design, fabrication, and testing to validate the efficacy of the design process. Results illustrate the value of the design process in concurrently evaluating the relative costs/benefits of these liner designs. This study also provides an application for demonstrating the integrated use of duct acoustic propagation/radiation and liner modeling tools in the design and evaluation of novel broadband liner concepts for complex engine configurations.

The lithostratigraphy of a marine kame delta-outwash fan complex at Pease AFB, Newington, NH

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

Dineen, R.J.; Manning, S.; McGeehan, K.

The overburden stratigraphy at Pease AFB is based on over 1,200 wells, borings, piezometers, and test pits, and includes five lithologic units: Fill, Upper Sand (US), Marine Clay and Silt (MCS), Lower Sand (LS), and Till (GT). The US is a yellow brown, poorly sorted sand to silty sand and is massive to laminated, and locally has hummocky bedding. The MCS (the Presumpscot Formation) is a dark gray, massive to laminated sandy to silty clay, and is locally interbedded with silty sand. The MCS contains a trace of organic matter, primarily as fine particles of peat. The LS is amore » gray to brown, poorly sorted, silty sand to gravelly sand that is massive to planar bedded and locally grades down into GT and/or upward into MCS. The GT consists of a massive to crudely bedded dark gray to dark brown, very poorly sorted, sandy silt to gravelly, silty sand. The US, MCS, LS and upper part of the GT were deposited in a marine environment at or near the ice margin. Pease AFB is built on two large fans of gravelly sand (LS plus US) that are bordered to the east by NW-SE till ridges (drumlins ). The northern-most fan is flat-topped with a surface elevation of 30 m ASL. The southern fan is more hummocky, with a surface elevation of 18.5 m ASL. Both fans coarsen towards the NW, and are interbedded with MCS towards the SE. The apices of the fans overlie deeply-scoured troughs in the rock surface. The fans are interpreted to be kame deltas or submarine outwash fans that are deposited along the retreating Wisconsinan ice margin by concentrated meltwater flow. Later, the US may have been deposited by marine shoreface erosion of the emergent fans as the ice front retreated and sea level fell.« less

Terrestrial Cosmogenic-Nuclide Dating of Alluvial Fans in Death Valley, California

USGS Publications Warehouse

Machette, Michael N.; Slate, Janet L.; Phillips, Fred M.

2008-01-01

We have used terrestrial cosmogenic nuclides (TCN) to establish the age of some of the most extensive Quaternary alluvial fans in Death Valley, California. These intermediate-age alluvial fans are most extensive on the western side of the valley, where tectonic deformation is considerably less pronounced than on the eastern side of the valley. These fans are characterized by a relatively smooth, densely packed desert pavement formed by well-varnished (blackened) clasts. These surfaces have been mapped as the Q2 gravel by previous workers and as unit Qai (intermediate age) by us. However, the intermediate-age gravels probably contain multiple subunits, as evidenced by slight differences in morphologic expression, soil formation, and inset geomorphic relations. The TCN technique used herein sums the cosmogenic 36Cl in approximately 2.5-meter-deep profiles through soil and host alluvium, thus avoiding some of the problems associated with the more typical surface-exposure dating of boulders or smaller clasts. Our TCN 36Cl dating of 12 depth profiles indicates that these intermediate-age (Qai) alluvial fans range from about 100 to 40 kilo-annum (ka), with a mean age of about 70 ka. An alternative interpretation is that alluvial unit Qai was deposited in two discrete episodes from 90 to 80 ka and from 60 to 50 ka, before and after MIS (marine oxygen-isotope stage) 4 (respectively). Without an intermediate-age unit, such as MIS 4 lake deposits, we can neither disprove nor prove that Qai was deposited in two discrete intervals or over a longer range of time. Thus, in Death Valley, alluvial unit Qai largely brackets MIS 4, which is not associated with a deep phase of Lake Manly. These Qai fans extend to elevations of about -46 meters (150 feet below sea level) and have not been transgressed by Lake Manly, suggesting that MIS 4 or MIS 2 lakes were rather shallow in Death Valley, perhaps because they lacked inflow from surface runoff of the Sierra Nevada drainages through Panamint Valley and over Wingate Wash. A remnant of ancient lake shoreline deposits that once extended across the Hanaupah Canyon fan constrains the timing and extent of the last deep cycle of Pleistocene Lake Manly. The lacustrine delta complex yields a 36Cl depth-profile date of 130 ka, which is consistent with deposition during a highstand of Lake Manly at the end of MIS 6. These deposits are presently at an altitude of about 30 meters above sea level (asl), which relates to a lake with a maximum depth of about 115 meters. Remnants of shoreline deposits at higher elevations on the southern margin of the Hanaupah Canyon fan complex are cut across older alluvium (unit Qao) and may be related to an MIS 6 highstand of at least 67 meters asl or, more likely, an older (MIS 8 or earlier) highstand that is poorly preserved and still undated in the valley. As part of our work on the west-side fans, we also dated an older phase of alluvial-fan deposits from the Trail Canyon fan complex, which is north of Hanaupah Canyon. A 36Cl depth-profile age of 170 ka suggests alluvial deposition of unit Qaio (older phase of Qao) took place prior to the MIS 6 highstand of Lake Manly. Knowing the absolute ages (or range in ages) of the intermediate-age (Qai) surfaces in Death Valley allows us to estimate the following rates of geologic processes: (1) a lateral slip rate of 5 millimeters per year for the northern Death Valley fault zone; (2) uplift of 50 meters in roughly the past 80,000 years for parts of the Mustard Canyon hills in east-central Death Valley; and (3) an estimated 10-40 m of dip-slip thrust movement on the Echo Canyon fault in Furnace Creek Canyon.

Fan filters, the 3-D Radon transform, and image sequence analysis.

PubMed

Marzetta, T L

1994-01-01

This paper develops a theory for the application of fan filters to moving objects. In contrast to previous treatments of the subject based on the 3-D Fourier transform, simplicity and insight are achieved by using the 3-D Radon transform. With this point of view, the Radon transform decomposes the image sequence into a set of plane waves that are parameterized by a two-component slowness vector. Fan filtering is equivalent to a multiplication in the Radon transform domain by a slowness response function, followed by an inverse Radon transform. The plane wave representation of a moving object involves only a restricted set of slownesses such that the inner product of the plane wave slowness vector and the moving object velocity vector is equal to one. All of the complexity in the application of fan filters to image sequences results from the velocity-slowness mapping not being one-to-one; therefore, the filter response cannot be independently specified at all velocities. A key contribution of this paper is to elucidate both the power and the limitations of fan filtering in this new application. A potential application of 3-D fan filters is in the detection of moving targets in clutter and noise. For example, an appropriately designed fan filter can reject perfectly all moving objects whose speed, irrespective of heading, is less than a specified cut-off speed, with only minor attenuation of significantly faster objects. A simple geometric construction determines the response of the filter for speeds greater than the cut-off speed.

Spine-fan reconnection. The influence of temporal and spatial variation in the driver

NASA Astrophysics Data System (ADS)

Wyper, P. F.; Jain, R.; Pontin, D. I.

2012-09-01

Context. From observations, the atmosphere of the Sun has been shown to be highly dynamic with perturbations of the magnetic field often lacking temporal or spatial symmetry. Despite this, studies of the spine-fan reconnection mode at 3D nulls have so far focused on the very idealised case with symmetric driving of a fixed spatial extent. Aims: We investigate the spine-fan reconnection process for less idealised cases, focusing on asymmetric driving and drivers with different length scales. We look at the initial current sheet formation and whether the scalings developed in the idealised models are robust in more realistic situations. Methods: The investigation was carried out by numerically solving the resistive compressible 3D magnetohydrodynamic equations in a Cartesian box containing a linear null point. The spine-fan collapse was driven at the null through tangential boundary driving of the spine foot points. Results: We find significant differences in the initial current sheet formation with asymmetric driving. Notable is the displacement of the null point position as a function of driving velocity and resistivity (η). However, the scaling relations developed in the idealised case are found to be robust (albeit at reduced amplitudes) despite this extra complexity. Lastly, the spatial variation is also shown to play an important role in the initial current sheet formation through controlling the displacement of the spine foot points. Conclusions: We conclude that during the early stages of spine-fan reconnection both the temporal and spatial nature of the driving play important roles, with the idealised symmetrically driven case giving a "best case" for the rate of current development and connectivity change. As the most interesting eruptive events occur in relatively short time frames this work clearly shows the need for high temporal and spatial knowledge of the flows for accurate interpretation of the reconnection scenario. Lastly, since the scalings developed in the idealised case remain robust with more complex driving we can be more confident of their use in interpreting reconnection in complex magnetic field structures.

20. Photocopy of photograph. Horgan, February 7, 1921. Negative #D ...

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

20. Photocopy of photograph. Horgan, February 7, 1921. Negative #D & H 21895 Original negative can be found in D & H collection of the Anthracite Heritage Museum, Scranton, Pennsylvania. INTERIOR VIEW OF BREAKER, TOP FLOORS, SHOWING DETAIL OF TOP SCREENS AND CRUSHERS AT TIME OF CONSTRUCTION - Marvine Colliery, Breaker No. 2, West side Boulevard Avenue, between East Parker Street & Route 380, Scranton, Lackawanna County, PA

Study of stator-vane fluctuating pressures in a turbofan engine for static and flight tests

NASA Technical Reports Server (NTRS)

Mueller, A. W.

1984-01-01

As part of a program to study the fan noise generated from turbofan engines, fluctuating surface pressures induced by fan-rotor wakes were measured on core- and bypass-stator outlet guide vanes of a modified JT15D-1 engine. Tests were conducted with the engine operating on an outdoor test stand and in flight. The amplitudes of pressures measured at fan-rotor blade-passage fundamental frequencies were generally higher and appeared less stable for the static tests than for the flight tests. Fluctuating pressures measured at the blade-passage frequency of the high-speed core compressor were interpreted to be acoustic; however, disturbance trace velocities for either the convected rotor wakes or acoustic pressures were difficult to interpret because of the complex environment.

Seismic patterns of a muddy contourite fan (Vema Channel, South Brazilian Basin) and a sandy distal turbidite deep-sea fan (Cap Ferret system, Bay of Biscay): a comparison

NASA Astrophysics Data System (ADS)

Faugères, J. C.; Imbert, P.; Mézerais, M. L.; Crémer, M.

1998-01-01

The aim of this paper is to discriminate the depositional facies, geometries and mechanisms of deposition of contouritic fans from those of turbidite distal fans, with a view to provide better resolution of reservoir prediction. Two examples are analysed: the Vema contouritic drift in the South Brazilian Basin and the Cap Ferret turbiditic fan in the Bay of Biscaye. The Vema contourite fan is a Neogene mud-rich accumulation (200-400 m thick), fed by Antarctic Bottom Water bottom currents and located downstream of the Rio Grande Rise. It forms one single-mound fan-shaped body in between two major channels, and where the main part of the deep circulation is funnelled into. As a result of the morphological and hydrological background, the comourite drift progrades mostly downstream. The accumulation was built as several depositional units ('channel-levee' systems) bounded by widespread discontinuities showing erosional patterns. This resulted from episodes of strong and/or unstable current activity producing the discontinuities, alternating with periods of relatively weak and stable currents and major deposition. The Pliocene-Quaternary Cap Ferret distal deep-sea fan is a thick (500 m) sand-rich turbiditic accumulation fed directly by an uplifting mountain range. The accumulation is developed downstream of a main turbiditic feeder channel and the volume of sediment involved is much higher than for the Vema contourite fan. It shows a complex network of shallow channels and low-relief levees which merge downstream into thin, sandy, sheet-like deposits. Several depositional units are stacked vertically. Each unit is built by the lateral migration of a 'channel-levee' system. The stacking pattern of the successive units is prograding towards the basin. The presence of major discontinuities cutting throughout a whole accumulation, and the fairly irregular geometry of the 'channel-levee' deposits (absence of any obvious migrating trend), appear to be the most distinctive features of a contourite fan. On the other hand, the lateral migration of the 'channel-level' geometries and the presence of erosional surfaces of limited extent and restricted to the channels, are the main diagnostic features of a distal turbidite fan. Otherwise the seismo-facies are fairly similar in both sedimentary bodies.

Reconnection at three dimensional magnetic null points: Effect of current sheet asymmetry

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

Wyper, P. F.; Jain, Rekha

2013-05-15

Asymmetric current sheets are likely to be prevalent in both astrophysical and laboratory plasmas with complex three dimensional (3D) magnetic topologies. This work presents kinematic analytical models for spine and fan reconnection at a radially symmetric 3D null (i.e., a null where the eigenvalues associated with the fan plane are equal) with asymmetric current sheets. Asymmetric fan reconnection is characterized by an asymmetric reconnection of flux past each spine line and a bulk flow of plasma across the null point. In contrast, asymmetric spine reconnection is characterized by the reconnection of an equal quantity of flux across the fan planemore » in both directions. The higher modes of spine reconnection also include localized wedges of vortical flux transport in each half of the fan. In this situation, two definitions for reconnection rate become appropriate: a local reconnection rate quantifying how much flux is genuinely reconnected across the fan plane and a global rate associated with the net flux driven across each semi-plane. Through a scaling analysis, it is shown that when the ohmic dissipation in the layer is assumed to be constant, the increase in the local rate bleeds from the global rate as the sheet deformation is increased. Both models suggest that asymmetry in the current sheet dimensions will have a profound effect on the reconnection rate and manner of flux transport in reconnection involving 3D nulls.« less

An integrated approach to flood hazard assessment on alluvial fans using numerical modeling, field mapping, and remote sensing

USGS Publications Warehouse

Pelletier, J.D.; Mayer, L.; Pearthree, P.A.; House, P.K.; Demsey, K.A.; Klawon, J.K.; Vincent, K.R.

2005-01-01

Millions of people in the western United States live near the dynamic, distributary channel networks of alluvial fans where flood behavior is complex and poorly constrained. Here we test a new comprehensive approach to alluvial-fan flood hazard assessment that uses four complementary methods: two-dimensional raster-based hydraulic modeling, satellite-image change detection, fieldbased mapping of recent flood inundation, and surficial geologic mapping. Each of these methods provides spatial detail lacking in the standard method and each provides critical information for a comprehensive assessment. Our numerical model simultaneously solves the continuity equation and Manning's equation (Chow, 1959) using an implicit numerical method. It provides a robust numerical tool for predicting flood flows using the large, high-resolution Digital Elevation Models (DEMs) necessary to resolve the numerous small channels on the typical alluvial fan. Inundation extents and flow depths of historic floods can be reconstructed with the numerical model and validated against field- and satellite-based flood maps. A probabilistic flood hazard map can also be constructed by modeling multiple flood events with a range of specified discharges. This map can be used in conjunction with a surficial geologic map to further refine floodplain delineation on fans. To test the accuracy of the numerical model, we compared model predictions of flood inundation and flow depths against field- and satellite-based flood maps for two recent extreme events on the southern Tortolita and Harquahala piedmonts in Arizona. Model predictions match the field- and satellite-based maps closely. Probabilistic flood hazard maps based on the 10 yr, 100 yr, and maximum floods were also constructed for the study areas using stream gage records and paleoflood deposits. The resulting maps predict spatially complex flood hazards that strongly reflect small-scale topography and are consistent with surficial geology. In contrast, FEMA Flood Insurance Rate Maps (FIRMs) based on the FAN model predict uniformly high flood risk across the study areas without regard for small-scale topography and surficial geology. ?? 2005 Geological Society of America.

Exploring the use of weathering indexes in an alluvial fan chronology

NASA Astrophysics Data System (ADS)

Hardenbicker, Ulrike; Watanabe, Makiko; Kotowich, Roberta

2015-04-01

Alluvial fan sediments can act as an archive of local environmental history. Two borehole cores (FN 350 cm and AG 850cm) from Holocene alluvial fans located in the Qu'Appelle Valley in southern Saskatchewan were analyzed in order to identify how changes in land use of upland catchment plateaus modified the pattern and rate of sediment delivery to the fan. Due to the lack of material for radiometric dating a chronology of depositional events within the alluvial fans was established by using lithostratigraphy data of soils and sediments. In order to establish a more detailed relative chronology we evaluated if weathering indexes (the Parker Index, the CaO/ZrO2 molar ratio, the Product Index) originally developed for studies of in situ weathering of bedrock, are suitable to assess sediment weathering within alluvial fan sediments. To quantify the degree of weathering within the sediment samples the three indexes of weathering were calculated using the proportions of elements measure by Energy Dispersive X-ray Spectroscopy and there is an inverse relationship between weathering index and sample age. For further statistical analyses the fan sediments were classified into three groups: a sheet flow facies of well sorted silt loam and sandy loam textures, bed load facies characterized by high sand and gravel content and layers with high organic matter in combination with higher clay content indicative of in situ weathering and soil development. First results show that the Product Index may be the most suitable weathering index to indicate weathering or input of less weathered sediment within the sheet flow and bed load facies. In general, the weathering indexes do not take into account complexities of the weathering processes nor the overall environmental conditions in an alluvial fan. But chemical weathering indexes accompanied by geophysical and geo-chemical information have value, especially when the amount of sample material is limited.

Geomorphic Controls on Aquifer Geometry in Northwestern India

NASA Astrophysics Data System (ADS)

van Dijk, W. M.; Densmore, A. L.; Sinha, R.; Gupta, S.; Mason, P. J.; Singh, A.; Joshi, S. K.; Nayak, N.; Kumar, M.; Shekhar, S.

2014-12-01

The Indo-Gangetic foreland basin suffers from one of the highest rates of groundwater extraction in the world, especially in the Indian states of Punjab, Haryana and Rajasthan. To understand the effects of this extraction on ground water levels, we must first understand the geometry and sedimentary architecture of the aquifer system, which in turn depend upon its geomorphic setting. We use satellite images and digital elevation models to map the geomorphology of the Sutlej and Yamuna river systems, while aquifer geometry is assessed using ~250 wells that extend to ~300 m depth in Punjab and Haryana. The Sutlej and Yamuna rivers have deposited large sedimentary fans at their outlets. Elongate downslope ridges on the fan surfaces form distributary networks that radiate from the Sutlej and Yamuna fan apices, and we interpret these ridges as paleochannel deposits associated with discrete fan lobes. Paleochannels picked out by soil moisture variations illustrate a complex late Quaternary history of channel avulsion and incision, probably associated with variations in monsoon intensity. Aquifer bodies on the Sutlej and Yamuna fans have a median thickness of 7 and 6 m, respectively, and follow a heavy-tailed distribution, probably because of stacked sand bodies. The percentage of aquifer material in individual lithologs decreases downstream, although the exponent on the thickness distribution remains the same, indicating that aquifer bodies decrease in number down fan but do not thin appreciably. Critically, the interfan area between the Sutlej and Yamuna fans has thinner aquifers and a lower proportion of aquifer material, despite its proximal location. Our data show that the Sutlej and Yamuna fan systems form the major aquifer systems in this area, and that their geomorphic setting therefore provides a first-order control on aquifer distribution and geometry. The large spatial heterogeneity of the system must be considered in any future aquifer management scheme.

Early Permian conodont fauna and stratigraphy of the Garden Valley Formation, Eureka County, Nevada

USGS Publications Warehouse

Wardlaw, Bruce R.; Gallegos, Dora M.; Chernykh, Valery V.; Snyder, Walter S.

2015-01-01

The lower Part of the Garden Valley Formation yields two distinct conodont faunas. One of late Asselian age dominated by Mesogondolella and Streptognathodus and one of Artinskian age dominated by Sweetognathus with Mesogondolella. The Asselian fauna contains the same species as those found in the type area of the Asselian in the southern Urals including Mesogondolella dentiseparata, described for the first time outside of the Urals. Apparatuses for Sweetognathus whitei, Diplognathodus stevensi, and Idioprioniodus sp. are described. The Garden Valley Formation represents a marine pro-delta basin and platform, and marine and shore fan delta complex deposition. The fan-delta complex was most likely deposited from late Artinskian to lateWordian. The Garden Valley Formation records tremendous swings in depositional setting from shallow-water to basin to shore.

Early Permian conodont fauna and stratigraphy of the Garden Valley Formation, Eureka County, Nevada

USGS Publications Warehouse

Wardlaw, Bruce R.; Gallegos, Dora M.; Chernykh, Valery V.; Snyder, Walter S.

2015-01-01

The lower part of the Garden Valley Formation yields two distinct conodont faunas. One of late Asselian age dominated by Mesogondolella and Streptognathodus and one of Artinskian age dominated by Sweetognathus with Mesogondolella. The Asselian fauna contains the same species as those found in the type area of the Asselian in the southern Urals including Mesogondolella dentiseparata, described for the first time outside of the Urals. Apparatuses for Sweetognathus whitei, Diplognathodus stevensi, and Idioprioniodus sp. are described. The Garden Valley Formation represents a marine pro-delta basin and platform, and marine and shore fan delta complex deposition. The fan-delta complex was most likely deposited from late Artinskian to late Wordian. The Garden Valley Formation records tremendous swings in depositional setting from shallow-water to basin to shore.

The Development of the Ducted Fan Noise Propagation and Radiation Code CDUCT-LaRC

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Farassat, F.; Pope, D. Stuart; Vatsa, Veer

2003-01-01

The development of the ducted fan noise propagation and radiation code CDUCT-LaRC at NASA Langley Research Center is described. This code calculates the propagation and radiation of given acoustic modes ahead of the fan face or aft of the exhaust guide vanes in the inlet or exhaust ducts, respectively. This paper gives a description of the modules comprising CDUCT-LaRC. The grid generation module provides automatic creation of numerical grids for complex (non-axisymmetric) geometries that include single or multiple pylons. Files for performing automatic inviscid mean flow calculations are also generated within this module. The duct propagation is based on the parabolic approximation theory of R. P. Dougherty. This theory allows the handling of complex internal geometries and the ability to study the effect of non-uniform (i.e. circumferentially and axially segmented) liners. Finally, the duct radiation module is based on the Ffowcs Williams-Hawkings (FW-H) equation with a penetrable data surface. Refraction of sound through the shear layer between the external flow and bypass duct flow is included. Results for benchmark annular ducts, as well as other geometries with pylons, are presented and compared with available analytical data.

21. Photocopy of photograph. Horgan, December 28, 1920. Negative #D ...

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

21. Photocopy of photograph. Horgan, December 28, 1920. Negative #D & H 21849 Original negative can be found in D & H collection of the Anthracite Heritage Museum, Scranton, Pennsylvania. INTERIOR VIEW OF BREAKER, MIDDLE FLOOR AREA, SHOWING DETAIL OF INSTALLATION OF FINE COAL SHAKERS AT TIME OF BREAKER CONSTRUCTION - Marvine Colliery, Breaker No. 2, West side Boulevard Avenue, between East Parker Street & Route 380, Scranton, Lackawanna County, PA

Evaluation of conditions along the grounding line of temperate marine glaciers: An example from Muir Inlet, Glacier Bay, Alaska

USGS Publications Warehouse

Seramur, K.C.; Powell, R.D.; Carlson, P.R.

1997-01-01

In the marine environment, stability of the glacier terminus and the location of subglacial streams are the dominant controls on the distribution of grounding-line deposits within morainal banks. A morainal bank complex in Muir Inlet, Glacier Bay, SE Alaska, is used to develop a model of terminus stability and location of subglacial streams along the grounding line of temperate marine glaciers. This model can be used to interpret former grounding-line conditions in other glacimarine settings from the facies architecture within morainal bank deposits. The Muir Inlet morainal bank complex was deposited between 1860 A.D. and 1899 A.D., and historical observations provide a record of terminus positions, glacial retreat rates and sedimentary sources. These data are used to reconstruct the depositional environment and to develop a correlation between sedimentary facies and conditions along the grounding line. Four seismic facies identified on the high-resolution seismic-reflection profiles are used to interpret sedimentary facies within the morainal bank complex. Terminus stability is interpreted from the distribution of sedimentary facies within three distinct submarine geomorphic features, a grounding-line fan; stratified ridges, and a field of push ridges. The grounding-line fan was deposited along a stable terminus and is represented on seismic-reflection profiles by two distinct seismic facies, a proximal and a distal fan facies. The proximal fan facies was deposited at the efflux of subglacial streams and indicates the location of former glacifluvial discharges into the sea. Stratified ridges formed as a result of the influence of a quasi-stable terminus on the distribution of sedimentary facies along the grounding line. A field of push ridges formed along the grounding line of an unstable terminus that completely reworked the grounding-line deposits through glacitectonic deformation. Between 1860 A.D. and 1899 A.D. (39 years), 8.96 x 108 m3 of sediment were deposited within the Muir Inlet morainal bank complex at an average annual sediment accumulation rate of 2.3 x 107 m3/a. This rate represents the annual sediment production capacity of the glacier when the Muir Inlet drainage basin is filled with glacial ice.

Early Miocene depositional environments in the northern margin of the Mediterranean, southwestern Anatolia

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

Yavuz, H.H.; Oercen, S.

1988-08-01

The continental and shallow marine clastics and carbonates exposed around the towns of Kale and Acipayam in southwestern Anatolia were investigated to interpret the depositional environments in the northern margin of the Mediterranean in terms of lithofacies and biozones. These deposits include Miogypsina intermedia and M. irregularis, indicating Burdigalian age when correlated with the same species in the different parts of the Tethys Sea and Indian-Pacific Oceans. The clastic lower part of the succession is characterized by sheet flow and braided-stream deposits of an alluvial-fan/fan-delta complex. Marine carbonates overlie these deposits, but in some places a transgressive lag deposit liesmore » between the unconformity surface and the carbonates. The lag deposit unit corresponds to the Gastropoda biozone, including Ostrea, Terebralia, and Pecten. Four carbonate facies are recognized: (1) Clayey limestones with ahermatypic corals, ostracods, macrofossils, and foraminifers. This facies corresponds to the Textularia-Rotalia biozone. (2) Packstones and grainstones with abundant nearshore and some offshore foraminifers, corresponding to the Miliolidae biozone. (3) Packstones and wackestones with offshore foraminifers. This facies includes the Miogypsina irregularis-Miogypsina intermedia biozone. (4) Boundstones and very poorly sorted reef-talus conglomerates including hermatypic corals, foraminifers, and binding foraminifers. This facies is the coral biozone. These sediments define the northern extent of the Tethys Sea in the investigated area during the Burdigalian. They were deposited in a shallow carbonate platform at the southern margin of the Anatolian mainland, which had a steep coast characterized by an alluvial-fan/fan-delta complex.« less

Geomorphological map and preliminary analysis of Quaternary sediments in the Planica-Tamar valley (Julian Alps, NW Slovenia)

NASA Astrophysics Data System (ADS)

Novak, Andrej; Šmuc, Andrej

2016-04-01

The Planica-Tamar valley is located in the Julian Alps in north-west Slovenia. The Planica-Tamar valley represents typical mountain glacial valley bounded by steep, mainly carbonate cliffs with some glacial deposits still preserved. The valley is currently being filled with numerous Holocene sediments deposited by rock falls, landslides, mass gravity flows and fluvial flows. These deposits are forming active or inactive interfingering talus slopes, alluvial and debris-flow fans, all of them with a complex history of sedimentation and erosion forming unconformity bounded sedimentary units. In order to make a thorough analysis of these deposits a detailed geomorphological map in a scale of 1:10 000 has been made. Six different types of sedimentary deposits were defined and mapped. These are moraines, lacustrine sediments, fluvio-glacial deposits, talus slopes, debris fans and alluvial fans. Other mapped features also include shape of ravines, their depths, ridges and direction of sedimentary flow. Additionally areas of active, semi-active and inactive sedimentation were marked. Moraines forms a ridge in the bottom of the valleys and are composed of unconsolidated, poorly sorted, subangular grains ranging from clay size to a few cubic meters big blocks. Lacustrine sediments are represented by laminated well sorted sand and silt, while fluvio-glacial deposits are composed of washed out subrounded sands and gravels. Talus slope deposits are characterised by clast-supported poorly sorted very angular gravel. Debris flow fans are represented by extremely poorly sorted matrix-supported gravels with grain size ranging from clay to few cubic meters big blocks. Alluvial fans are composed by variety of sedimentary textures. Sediments at the fan apex are clast-supported poorly sorted very angular gravels with up to a few cubic meters big block. In the middle part of the fan the sieve deposits are common, while in the distal parts a few centimeters thick layers of sand and moderately sorted clast or sandy matrix-supported angular gravels occur. In cross-sections of alluvial fans distinct palaeosoil horizons are present indicating longer inactivity of that part of the fan. The geomorphological map forms a base for further research and thorough analysis of Quaternary deposits in order to reconstruct the Holocene dynamic of triggering and sedimentation of different types of slope deposits and relate them to base rock geology, tectonic and local/regional climate events. Key words: geomorphological mapping, Holocene slope deposits, alluvial fans, debris fans, Alpine geomorphology.

Mental hoop diaries: Emotional memories of a college basketball game in rival fans

PubMed Central

Botzung, Anne; Rubin, David C.; Miles, Amanda; Cabeza, Roberto; LaBar, Kevin S.

2012-01-01

The rivalry between the men’s basketball teams of Duke University and the University of North Carolina-Chapel Hill (UNC) is one of the most storied traditions in college sports. A subculture of students at each university form social bonds with fellow fans, develop expertise in college basketball rules, team statistics, and individual players, and self-identify as a member of a fan group. The present study capitalized on the high personal investment of these fans and the strong affective tenor of a Duke-UNC basketball game to examine the neural correlates of emotional memory retrieval for a complex sporting event. Male fans watched a competitive, archived game in a social setting. During a subsequent functional magnetic resonance imaging session, participants viewed video clips depicting individual plays of the game that ended with the ball being released towards the basket. For each play, participants recalled whether or not the shot went into the basket. Hemodynamic signal changes time-locked to correct memory decisions were analyzed as a function of emotional intensity and valence, according to the fan’s perspective. Results showed intensity-modulated retrieval activity in midline cortical structures, sensorimotor cortex, the striatum, and the medial temporal lobe, including the amygdala. Positively-valent memories specifically recruited processing in dorsal frontoparietal regions, and additional activity in the insula and medial temporal lobe for positively-valent shots recalled with high confidence. This novel paradigm reveals how brain regions implicated in emotion, memory retrieval, visuomotor imagery, and social cognition contribute to the recollection of specific plays in the mind of a sports fan. PMID:20147540

Design and Development of a Regenerative Blower for EVA Suit Ventilation

NASA Technical Reports Server (NTRS)

Izenson, Michael G.; Chen, Weibo; Hill, Roger W.; Phillips, Scott D.; Paul, Heather L.

2011-01-01

Ventilation subsystems in future space suits require a dedicated ventilation fan. The unique requirements for the ventilation fan - including stringent safety requirements and the ability to increase output to operate in buddy mode - combine to make a regenerative blower an attractive choice. This paper describes progress in the design, development, and testing of a regenerative blower designed to meet requirements for ventilation subsystems in future space suits. We have developed analysis methods for the blower s complex, internal flows and identified impeller geometries that enable significant improvements in blower efficiency. We verified these predictions by test, measuring aerodynamic efficiencies of 45% at operating conditions that correspond to the ventilation fan s design point. We have developed a compact motor/controller to drive the blower efficiently at low rotating speed (4500 rpm). Finally, we have assembled a low-pressure oxygen test loop to demonstrate the blower s reliability under prototypical conditions.

Organic carbon accumulation in modern sediments of the Angola basin influenced by the Congo deep-sea fan

NASA Astrophysics Data System (ADS)

Baudin, François; Martinez, Philippe; Dennielou, Bernard; Charlier, Karine; Marsset, Tania; Droz, Laurence; Rabouille, Christophe

2017-08-01

Geochemical data (total organic carbon-TOC content, δ13Corg, C:N, Rock-Eval analyses) were obtained on 150 core tops from the Angola basin, with a special focus on the Congo deep-sea fan. Combined with the previously published data, the resulting dataset (322 stations) shows a good spatial and bathymetric representativeness. TOC content and δ13Corg maps of the Angola basin were generated using this enhanced dataset. The main difference in our map with previously published ones is the high terrestrial organic matter content observed downslope along the active turbidite channel of the Congo deep-sea fan till the distal lobe complex near 5000 m of water-depth. Interpretation of downslope trends in TOC content and organic matter composition indicates that lateral particle transport by turbidity currents is the primary mechanism controlling supply and burial of organic matter in the bathypelagic depths.

Compressible Boundary Layer Investigation for Ramjet/scramjet Inlets and Nozzles

NASA Astrophysics Data System (ADS)

Goldfeld, M. A.; Starov, A. V.; Semenova, Yu. V.

2005-02-01

The results of experimental investigation of a turbulent boundary layer on compression and expansion surfaces are presented. They include the study of the shock wave and/or expansion fan action upon the boundary layer, boundary layer separation and its relaxation. Complex events of paired interactions and the flow on compression convex-concave surfaces were studied [M. Goldfeld, 1993]. The possibility and conditions of the boundary layer relaminarization behind the expansion fan and its effect on the relaxation length are presented. Different model configurations for wide range conditions were investigated. Comparison of results for different interactions was carried out.

The Himalaya-Bengal Fan source to sink system - new insights by correlation of re-processed seismic data and IODP Expedition 354 results

NASA Astrophysics Data System (ADS)

Bergmann, Fenna; Schwenk, Tilmann; Spiess, Volkard; France-Lanord, Christian

2016-04-01

The Bengal Fan, hosted in the northern Indian Ocean, is the largest submarine fan on Earth. Fan evolution started in the Early Eocene as a direct response to the collision of India with the Asian continent in Middle Paleocene times. Subsequently the Himalayan plateau uplift was initiated. Thereby generated interactions with the regional climate caused the evolution of the Indian monsoonal system. Drained by the rivers Ganges and Brahmaputra, ~ 80% of eroded Himalayan sediments are deposited in the Bengal Fan. Hence, the Fan provides the most complete record of the Himalayan history and is well suited to investigate the direct link between the tectonic uplift and the climate evolution of the region. Sediments are transported onto the deep sea fan by turbidity currents building up chan-nel-levee systems. These channel-levee systems are the main architectural elements of the Bengal Fan and are suspected to have their onset in Late Miocene times. Frequent channel avulsion on the upper fan led to the abandonment of old channels and formation of new channel-levee systems or even channel-reoccupation. This complex erosional/depositional system involves lateral depocenter migration, probably on millennial timescales. Conse-quently, investigations of the Himalaya as sediment source begins with a comprehensive understanding of transport, deposition and modification within the Bengal Fan sediment sink. In February/March 2015 the IODP Expedition 354 drilled at 7 sites along a ~320 km long E-W transect at 8° N. Aiming at the recovery of pre-fan deposits and deposits of the Pliocene and Upper Miocene Fan evolution, three deep sites (900 - 1200 mbsf) were realized. These where complemented by four shallow sites (200-300 mbsf) for a detailed study of the depos-its of the last 1-2 million years, including the latest known channel activities (Holocene times). Several channel-levee systems and inter-channel deposits were drilled, active at different times of Fan evolution. To connect the sites of the drilling transect by means of seismo-stratigraphic analysis a large seismo-acoustic dataset gathered during cruises SO93 (1994), SO125/126 (1997) and SO188 (2006), all carried out in cooperation between the University of Bremen and the BGR, Hannover, is available. The dataset contains multichannel seismic data acquired with differ-ent seismic sources (GI-Gun/Watergun) to achieve differing subbottom penetration/resolution ratios. Although most of the pre-site survey data were already processed, major improve-ment could be gained by thoroughly (re) processing using new processing techniques and software developments. First processing results show significantly enhanced S/N ratio, reso-lution and reflector coherency. Full processing of the Watergun data was conducted for the first time. This high vertical resolution data has so far never been investigated and comple-ments the database, especially for a more detailed study of the upper few hundred meters of Bengal Fan deposits. First examinations of the watergun data in combination with drilling results proved them to be beneficial for the crucial borehole - seismic correlation and the investigations of the internal levee architecture, especially for the latest active channel-levee system.

Evaluation of Alternative Methods for Testing the Bioefficacy of Household Ambient Insecticide Products Against Aedes albopictus.

PubMed

Cassini, Rudi; Scremin, Mara; Contiero, Barbara; Drago, Andrea; Vettorato, Christian; Marcer, Federica; di Regalbono, Antonio Frangipane

2016-06-01

Ambient insecticides are receiving increasing attention in many developed countries because of their value in reducing mosquito nuisance. As required by the European Union Biocidal Products Regulation 528/2012, these devices require appropriate testing of their efficacy, which is based on estimating the knockdown and mortality rates of free-flying (free) mosquitoes in a test room. However, evaluations using free mosquitoes present many complexities. The performances of 6 alternative methods with mosquitoes held in 2 different cage designs (steel wire and gauze/plastic) with and without an operating fan for air circulation were monitored in a test room through a closed-circuit television system and were compared with the currently recommended method using free mosquitoes. Results for caged mosquitoes without a fan showed a clearly delayed knockdown effect, whereas outcomes for caged mosquitoes with a fan recorded higher mortality at 24 h, compared to free mosquitoes. Among the 6 methods, cages made of gauze and plastic operating with fan wind speed at 2.5-2.8 m/sec was the only method without a significant difference in results for free mosquitoes, and therefore appears as the best alternative to assess knockdown by ambient insecticides accurately.

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.

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.

Experimental Investigation of a Morphing Nacelle Ducted Fan

NASA Technical Reports Server (NTRS)

Kondor, Shayne A.; Moore, Mark

2005-01-01

The application of Circulation Control to the nacelle of a shrouded fan is proposed as a means to enhance off-design performance of the shrouded fan. Typically, a fixed geometry shroud is efficient at a single operating condition. Modifying circulation about the fixed geometry is proposed as a means to virtually morph the shroud without moving surfaces. This approach will enhance off-design-point performance with minimal complexity, weight, and cost. Termed the Morphing Nacelle, this concept provides an attractive propulsion option for Vertical Take-off and Landing (VTOL) aircraft, such conceptual Personal Air Vehicle (PAV) configurations proposed by NASA. An experimental proof of concept investigation of the Morphing Nacelle is detailed in this paper. A powered model shrouded fan model was constructed with Circulation Control (CC) devices integrated in the inlet and exit of the nacelle. Both CC devices consisted of an annular jet slot directing a jet sheet tangent to a curved surface, generally described as a Coanda surface. The model shroud was tailored for axial flight, with a diffusing inlet, but was operated off-design condition as a static lifting fan. Thrust stand experiments were conducted to determine if the CC devices could effectively improve off-design performance of the shrouded fan. Additional tests were conducted to explore the effectiveness of the CC devices a means to reduce peak static pressure on the ground below a lifting fan. Experimental results showed that off-design static thrust performance of the model was improved when the CC devices were employed under certain conditions. The exhaust CC device alone, while effective in diffusing the fan exhaust and improving weight flow into shroud inlet, tended to diminish performance of the fan with increased CC jet momentum. The inlet CC device was effective at reattaching a normally stalled inlet flow condition, proving an effective means of enhancing performance. A more dramatic improvement in static thrust was obtained when the inlet and exit CC devices were operated in unison, but only over a limited range of CC jet momentum. Operating the nacelle inlet and exit CC devices together proved very effective in reducing peak ground plane static pressure, while maintaining static thrust. The Morphing Nacelle concept proved effective at enhancing off-design performance of the model; however, additional investigation is necessary to generalize the results.

Facies heterogeneity, pay continuity, and infill potential in barrier-island, fluvial, and submarine fan reservoirs: examples from the Texas Gulf Coast and Midland basins

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

Ambrose, W.A.; Tyler, N.

1989-03-01

Three reservoirs representing different depositional environments - barrier island (West Ranch field, south-central Texas), fluvial (La Gloria field, south Texas), and submarine fan (Spraberry trend, Midland basin) - illustrate variations in reservoir continuity. Pay continuity methods based on facies geometry and variations in permeability and thickness between wells can quantify reservoir heterogeneity in each of these examples. Although barrier-island reservoirs are relatively homogeneous, West Ranch field contains wide (1000-5000 ft or 300-1500 m) dip-parallel belts of lenticular inlet-fill facies that disrupt reservoir continuity in the main barrier-core facies. Other reservoir compartments in West Ranch field are in flood-tidal delta depositsmore » partly encased in lagoonal mudstones updip of the barrier core. Fluvial reservoirs have a higher degree of internal complexity than barrier-island reservoirs. In La Gloria field, reservoirs exhibit significant heterogeneity in the form of numerous sandstone stringers bounded vertically and laterally by thin mudstone layers. Successful infill wells in La Gloria field contact partly drained reservoir compartments in splay deposits that pinch out laterally into flood-plain mudstones. Recompletions in vertically isolated sandstone stringers in La Gloria field contact other reservoir compartments. Submarine fan deposits are extremely heterogeneous and may have the greatest potential for infill drilling to tap isolated compartments in clastic reservoirs. The Spraberry trend contains thin discontinuous reservoir sandstones deposited in complex mid-fan channels. Although facies relationships in Spraberry reservoirs are similar to those in fluvial reservoirs in La Gloria field, individual pay stringers are thinner and more completely encased in low-permeability mudstone facies.« less

Probabilistic Analysis of Large-Scale Composite Structures Using the IPACS Code

NASA Technical Reports Server (NTRS)

Lemonds, Jeffrey; Kumar, Virendra

1995-01-01

An investigation was performed to ascertain the feasibility of using IPACS (Integrated Probabilistic Assessment of Composite Structures) for probabilistic analysis of a composite fan blade, the development of which is being pursued by various industries for the next generation of aircraft engines. A model representative of the class of fan blades used in the GE90 engine has been chosen as the structural component to be analyzed with IPACS. In this study, typical uncertainties are assumed in the level, and structural responses for ply stresses and frequencies are evaluated in the form of cumulative probability density functions. Because of the geometric complexity of the blade, the number of plies varies from several hundred at the root to about a hundred at the tip. This represents a extremely complex composites application for the IPACS code. A sensitivity study with respect to various random variables is also performed.

Pleistocene lake outburst floods and fan formation along the eastern Sierra Nevada, California: implications for the interpretation of intermontane lacustrine records

NASA Astrophysics Data System (ADS)

Benn, Douglas I.; Owen, Lewis A.; Finkel, Robert C.; Clemmens, Samuel

2006-11-01

Variations in the rock flour fraction in intermontane lacustrine sediments have the potential to provide more complete records of glacier fluctuations than moraine sequences, which are subject to erosional censoring. Construction of glacial chronologies from such records relies on the assumption that rock flour concentration is a simple function of glacier extent. However, other factors may influence the delivery of glacigenic sediments to intermontane lakes, including paraglacial adjustment of slope and fluvial systems to deglaciation, variations in precipitation and snowmelt, and lake outburst floods. We have investigated the processes and chronology of sediment transport on the Tuttle and Lone Pine alluvial fans in the eastern Sierra Nevada, California, USA, to elucidate the links between former glacier systems located upstream and the long sedimentary record from Owens Lake located downstream. Aggradation of both fans reflects sedimentation by three contrasting process regimes: (1) high magnitude, catastrophic floods, (2) fluvial or glacifluvial river systems, and (3) debris flows and other slope processes. Flood deposits are represented by multiple boulder beds exposed in section, and extensive networks of large palaeochannels and boulder deposits on both fan surfaces. Palaeohydrological analysis implies peak discharges in the order of 10 3-10 4 m 3 s -1, most probably as the result of catastrophic drainage of ice-, moraine-, and landslide-dammed lakes. Cosmogenic radionuclide surface exposure dating shows that at least three flood events are represented on each fan, at 9-13, 16-18 and 32-44 ka (Tuttle Fan); and at ˜23-32, ˜80-86 ka, and a poorly constrained older event (Lone Pine Fan). Gravels and sands exposed in both fans represent fluvial and/or glacifluvial sediment transport from the Sierra Nevada into Owens Valley, and show that river systems incised and reworked older sediment stored in the fans. We argue that millennial-scale peaks in rock flour abundance in the Owens Lake core reflect (1) fluctuations in primary subglacial erosion in the catchments in response to glacier advance-retreat cycles; (2) short-lived pulses of sediment delivered directly by catastrophic flood events; and (3) sediment released from storage in alluvial fans by fluvial and glacifluvial incision and reworking. As a result of this complexity the coarse sediment peaks in lake deposits may not simply reflect periods of increased glaciation, but likely also reflect changes in sediment storage and flux controlled by paraglacial processes. Current dating evidence is inadequate to allow precise correlation of individual flood or incision events with the Owens Lake rock flour record, although given the widespread occurrence of flood deposits in fans along the eastern margins of the Sierra Nevada, it is clear that fan deposition and incision played a very important role in modulating the delivery of glacigenic sediment to Owens Lake.

Short-range magnetic order, irreversibility and giant magnetoresistance near the triple points in the (x, T) magnetic phase diagram of ZrMn6Sn6-xGax

NASA Astrophysics Data System (ADS)

Mazet, T.; Ihou-Mouko, H.; Marêché, J.-F.; Malaman, B.

2010-04-01

We have studied pseudo-layered ZrMn6Sn6-xGax intermetallics (0.55 ≤ x ≤ 0.81) using magnetic, magnetoresistivity and powder neutron diffraction measurements. All the alloys studied have magnetic ordering temperatures in the 450-490 K temperature range. They present complex temperature-dependent partially disordered magnetic structures whose ferromagnetic component develops upon increasing the Ga content. ZrMn6Sn6-xGax alloys with x ≤ 0.69 are essentially collinear antiferromagnets at high-temperature and adopt antifan-like arrangements at low temperature. For x ≥ 0.75, the alloys order ferromagnetically and evolve to a fan-like structure upon cooling. The intermediate compositions (x = 0.71 and 0.73) present a canted fan-like order at high temperature and another kind of antifan-like arrangement at low temperature. The degree of short-range order tends to increase upon approaching the intermediate compositions. The (x, T) phase diagram contains two triple points (x ~ 0.70; T ~ 460 K and x ~ 0.74; T ~ 455 K), where the paramagnetic, an incommensurate and a commensurate phases meet, which possess some of the features of Lifshitz point. Irreversibilities manifest in the low-temperature magnetization curves at the antifan-fan or fan-ferromagnetic boundaries as well as inside the fan region. Giant magnetoresistance is observed, even above room temperature.

Dimension-controlled assemblies of anion-responsive π-electronic systems bearing aryl substituents with fan-shaped geometries.

PubMed

Lakshmi, Vellanki; Haketa, Yohei; Yamakado, Ryohei; Yasuda, Nobuhiro; Maeda, Hiromitsu

2017-03-30

Pyrrole-4-aryl-substituted dipyrrolyldiketone BF 2 complexes as anion-responsive π-electronic molecules were synthesized via a 3,5-dimethylpyrrole precursor. Mesophases were observed in derivatives that possessed long alkyl chains on the pyrrole-4-aryl groups along with their anion complexes as ion-pairing assemblies in combination with appropriate cations.

Expression of the gene cluster associated with the Escherichia coli pilus adhesin K99.

PubMed

Lee, J H; Isaacson, R E

1995-10-01

The biogenesis of the pilus adhesin K99 is dependent on the expression of eight contiguous genes, fanA to fanH. Transposon mutants were prepared by using TnlacZ and TnphoA, and selected transposon mutants were used to measure expression of each K99 gene. Expression of the K99 genes is likely controlled at the transcription level, since in general, there were no differences between the results obtained with the two transposons. fanC was the most highly expressed, and fanD was expressed at very low levels. The expression of TnlacZ fusions in fanA and fanB fusions was high. Deletion of fanA, fanB, and part of fanC abolished the expression of fanD but had no effect on the distal genes fanE to fanH. To locate the DNA regions required for expression of fanE to fanH, deletion mutations were prepared and the effects on expression of fanE to fanH were determined. The deletion of a segment between fanD and fanE abolished fanE and fanF expression but did not affect fanG and fanH. The deletion of a portion of fanF (approximately 1 kb proximal to fanG) abolished the expression of fanG and fanH. These results indicate the presence of regulatory elements proximal to fanE and to fanG. Putative promoters were identified in these regions by DNA homology and by primer extension. A stem-loop structure that may act as a transcriptional attenuator of fanF was also found at the beginning of fanF. These data confirm our previous model of K99 transcriptional organization.

Expression of the gene cluster associated with the Escherichia coli pilus adhesin K99.

PubMed Central

Lee, J H; Isaacson, R E

1995-01-01

The biogenesis of the pilus adhesin K99 is dependent on the expression of eight contiguous genes, fanA to fanH. Transposon mutants were prepared by using TnlacZ and TnphoA, and selected transposon mutants were used to measure expression of each K99 gene. Expression of the K99 genes is likely controlled at the transcription level, since in general, there were no differences between the results obtained with the two transposons. fanC was the most highly expressed, and fanD was expressed at very low levels. The expression of TnlacZ fusions in fanA and fanB fusions was high. Deletion of fanA, fanB, and part of fanC abolished the expression of fanD but had no effect on the distal genes fanE to fanH. To locate the DNA regions required for expression of fanE to fanH, deletion mutations were prepared and the effects on expression of fanE to fanH were determined. The deletion of a segment between fanD and fanE abolished fanE and fanF expression but did not affect fanG and fanH. The deletion of a portion of fanF (approximately 1 kb proximal to fanG) abolished the expression of fanG and fanH. These results indicate the presence of regulatory elements proximal to fanE and to fanG. Putative promoters were identified in these regions by DNA homology and by primer extension. A stem-loop structure that may act as a transcriptional attenuator of fanF was also found at the beginning of fanF. These data confirm our previous model of K99 transcriptional organization. PMID:7558331

Origin and distribution of the organic matter in the distal lobe of the Congo deep-sea fan - A Rock-Eval survey

NASA Astrophysics Data System (ADS)

Baudin, François; Stetten, Elsa; Schnyder, Johann; Charlier, Karine; Martinez, Philippe; Dennielou, Bernard; Droz, Laurence

2017-08-01

The Congo River, the second largest river in the world, is a major source of organic matter for the deep Atlantic Ocean because of the connection of its estuary to the deep offshore area by a submarine canyon which feeds a vast deep-sea fan. The lobe zone of this deep-sea fan is the final receptacle of the sedimentary inputs presently channelled by the canyon and covers an area of 2500 km². The quantity and the source of organic matter preserved in recent turbiditic sediments from the distal lobe of the Congo deep-sea fan were assessed using Rock-Eval pyrolysis analyses. Six sites, located at approximately 5000 m water-depth, were investigated. The mud-rich sediments of the distal lobe contain high amounts of organic matter ( 3.5 to 4% Corg), the origin of which is a mixture of terrestrial higher-plant debris, soil organic matter and deeply oxidized phytoplanktonic material. Although the respective contribution of terrestrial and marine sources of organic matter cannot be precisely quantified using Rock-Eval analyses, the terrestrial fraction is dominant according to similar hydrogen and oxygen indices of both suspended and bedload sediments from the Congo River and that deposited in the lobe complex. The Rock-Eval signature supports the 70% to 80% of the terrestrial fraction previously estimated using C/N and δ13Corg data. In the background sediment, the organic matter distribution is homogeneous at different scales, from a single turbiditic event to the entire lobe, and changes in accumulation rates only have a limited effect on the quantity and quality of the preserved organic matter. Peculiar areas with chemosynthetic bivalves and/or bacterial mats, explored using ROV Victor 6000, show a Rock-Eval signature similar to background sediment. This high organic carbon content associated to high sedimentation rates (> 2 to 20 mm.yr-1) in the Congo distal lobe complex implies a high burial rate for organic carbon. Consequently, the Congo deep-sea fan represents an enormous sink of terrestrial organic matter when compared to other turbiditic systems over the world.

Feedback (F) Fueling Adaptation (A) Network Growth (N) and Self-Organization (S): A Complex Systems Design and Evaluation Approach to Professional Development

ERIC Educational Resources Information Center

Yoon, Susan A.; Klopfer, Eric

2006-01-01

This paper reports on the efficacy of a professional development framework premised on four complex systems design principles: Feedback, Adaptation, Network Growth and Self-organization (FANS). The framework is applied to the design and delivery of the first 2 years of a 3-year study aimed at improving teacher and student understanding of…

Advanced Computational Aeroacoustics Methods for Fan Noise Prediction

NASA Technical Reports Server (NTRS)

Envia, Edmane (Technical Monitor); Tam, Christopher

2003-01-01

Direct computation of fan noise is presently not possible. One of the major difficulties is the geometrical complexity of the problem. In the case of fan noise, the blade geometry is critical to the loading on the blade and hence the intensity of the radiated noise. The precise geometry must be incorporated into the computation. In computational fluid dynamics (CFD), there are two general ways to handle problems with complex geometry. One way is to use unstructured grids. The other is to use body fitted overset grids. In the overset grid method, accurate data transfer is of utmost importance. For acoustic computation, it is not clear that the currently used data transfer methods are sufficiently accurate as not to contaminate the very small amplitude acoustic disturbances. In CFD, low order schemes are, invariably, used in conjunction with unstructured grids. However, low order schemes are known to be numerically dispersive and dissipative. dissipative errors are extremely undesirable for acoustic wave problems. The objective of this project is to develop a high order unstructured grid Dispersion-Relation-Preserving (DRP) scheme. would minimize numerical dispersion and dissipation errors. contains the results of the funded portion of the project. scheme on an unstructured grid has been developed. constructed in the wave number space. The characteristics of the scheme can be improved by the inclusion of additional constraints. Stability of the scheme has been investigated. Stability can be improved by adopting the upwinding strategy.

Two novel genes, fanA and fanB, involved in the biogenesis of K99 fimbriae.

PubMed

Roosendaal, E; Boots, M; de Graaf, F K

1987-08-11

The nucleotide sequence of the region located transcriptionally upstream of the K99 fimbrial subunit gene (fanC) was determined. Several putative transcription signals and two open reading frames, designated fanA and fanB, became apparent. Frameshift mutations in fanA and fanB reduced K99 fimbriae expression 8-fold and 16-fold, respectively. Complementation of the mutants in trans restored the K99 expression to about 75% of the wild type level, indicating that fanA and fanB code for transacting polypeptides involved in the biogenesis of K99 fimbriae. The fanA and fanB gene products FanA and FanB were not detectable in minicell preparations, indicating that both polypeptides are synthesized in very small amounts. However, in an in vitro DNA directed translation system FanA and FanB could be identified. The deduced amino acid sequences of FanA and FanB showed that both polypeptides contain no signal peptides, indicating a cytoplasmic location. Furthermore, the polypeptides are very hydrophilic, mainly basic, and exhibit remarkable homology to each other and to a regulatory protein (papB) encoded by the pap-operon (1). Some of these features are characteristics of nucleic acid binding proteins, which suggests that FanA and FanB have a regulatory function in the synthesis of FanC and the auxiliary polypeptides FanD-H.

Morphometry of Alluvial Fans in a Polar Desert (Svalbard, Norway): Implications for Interpreting Martian Fans

NASA Astrophysics Data System (ADS)

Hauber, E.; Preusker, F.; Trauthan, F.; Reiss, D.; Zanetti, M.; Jaumann, R.; Hiesinger, H.

2009-04-01

Alluvial fan-like landforms have been identified on Mars [e.g., 1-3]. Alluvial fans contain information on several controlling factors (tectonism, climate, lithology/geology), and therefore the investigation of possible Martian fans can reveal information about the planet`s climate. In lieu of direct observations of active depositional processes on Martian fans, comparisons with terrestrial analogues can constrain models of Martian fan formation derived from remote sensing data. Since present-day Mars is cold and dry, alluvial fans formed in cold deserts should be considered as useful analogues. The probably closest climatic analogue to Mars on Earth are the Antarctic Dry Valleys [5], but polar deserts can also be found in the Arctic. We report on our field work in summer 2008 and a simultaneous flight campaign with an airborne version (HRSC-AX) of the High Resolution Stereo Camera (HRSC) onboard Mars Express [6]. The results are compared with measurements of Martian fans, based on HRSC DEM. Our study area is in Svalbard near Longyearbyen (78°13'0"N, 15°38'0"E), around mountains of Mesozoic layered sandstones and shales) on the northern side of Adventfjorden. Climate data are available from the nearby Longyearbyen airport (just a few km from the study area). The present climate is arctic [7], with low mean annual air temperatures and very low precipitation, mostly as snow. Stereo images acquired in July 2008 (at the end of the snow melting season) were processed to orthoimages with a spatial resolution of 20 cm/pixel, and corresponding Digital Elevation Models (DEM) with a grid spacing of 50 cm/pixel. Simultaneous field measurements focused on channels and levees (widths, depths, heights), which were determined at vertical increments of 10 m, together with the local slope. Alluvial fans in the study area are present on slopes of all orientations. They typically coalesce into bajadas. Basically all alluvial fans in the study area are characterized by sinuous channels, many of which display well-developed lateral levees, and debris tongues. Boulder-sized (>1 m) rocks are present, but rare. Where a vertical section of the fan can be observed (typically at the toe, where braided rivers cut the fans), it appears poorly sorted. Following the reasoning of, e.g., [8,9], we conclude that the fans in our study area are dominated by debris flows. However, fluvial processes might also have been involved, and the complex interplay between fluvial incision and debris flows on alluvial fans is well known also from fans in different climatic environments [e.g., 10]. Topographic profiles along 55 fans were measured in HRSC-AX DEM. Fan length ranges between 80 m and about 800 m, with heights between 9 and 140 m (from apex to toe). The profiles of the Svalbard fans can be approximated very well with a power law function. Overall gradients vary between 0.11 and 0.43, with a peak at 0.18-0.2. Several measures have been suggested to quantify the concavity of river and fan profiles [e.g., 1, 11]. We use a simple method, which was suggested by Langbein [12] and is still widely used [e.g., 9, 13,14]. The Langbein-concavity of the fan profiles shows a continous range between 0 and 0.53. The topography of Martian fan-like features [2,3] is studied on the basis of DEM derived from HRSC stereo data [15,16], with a grid spacing of 50-100 m. An example of a profile along a Martian fan in Holden crater exhibits a Langbein-concavity of 0.194 and a gradient of 0.069. While the concavity falls in the range observed on Svalbard, the gradient is less. Another major difference is the fan dimension, with the fan in Holden Crater being much larger. We also produced a HRSC DEM of Mojave Crater on Mars, which displays a number of fans with dimensions similar to those on Svalbard [3], and discuss the relationship between local slopes and fans in Mojave Crater. Alluvial fans form by one or a combination of the following mechanisms: avulsing channelized rivers, sheet flows, and debris flows [17]. Previous studies comparing Martian and terrestrial fans have examined the usefulness of the concavity of along-fan profiles to discriminate between fluvially-dominated fans (concave-upward profiles) and debris flow-dominated fans (linear profiles) [1,2]. Morphological observations suggest that Svalbard fans are heavily affected by debris flows. However, their profiles show a continuum between more or less linear profiles and distinct concave-upward profiles, independent of orientation (which possibly controls snow accumulation and melting, and therefore depositional processes). We conclude that morphometric measures alone do not enable an unambiguous interpretation of processes acting on alluvial fans. Instead, complementary morphologic studies using high-resolution images seem to be required to discriminate between debris flows and fluvial activity on Mars, e.g., can we identify levees or debris tongues in HiRISE images? Their resolution is roughly 30 cm/px and should enable it. Even then, quantifiying the respective role of different depositional processes might be hard to achieve. [1] Moore, J.M. & Howard, A.D. (2005) JGR, 110, E04005, doi: 10.1029/2004JE00-2352. [2] Williams, R.M.E. et al. (2006) GRL, 33, L10201, doi: 10.1029/2005GL025618. [3] Williams, R.M.E. & Malin, M.C. (2008) Icarus, 198, 365-383. [4] Bull, W.B. (1977) Prog. Phys. Geogr., 1, 222-270. [5] Marchant, D.R. & Head, J.W. (2007) Icarus, 192, 187-222. [6] Jaumann, R. et al. (2007) Planet. Space Sci., 55, 928-952. [7] Hanssen-Bauer, I. & Førland, E.J. (1998) Climate Res., 10, 143-153. [8] De Scally, F.A. & Owens, I.F. (2004) Earth Surf. Proc. Landforms, 29, 311-322. [9] Blair, T.C. & McPherson, J.G. (1998) J. Sediment. Res., 68, 800- 818. [10] Whipple, K.X. & Dunne, T. (1992) Geol. Soc. Amer. Bull., 104, 887-900. [11] Zaprowski, B.J. et al. (2005) JGR, 110, F03004, doi: 10.1029/2004JF000138. [12] Langbein, W.B. (1964) USGS Prof. Paper 501 B, 119-122. [13] Phillips, J.D. & Lutz, J.D. (2008) Geomorphology 102, 554-566. [14] Larue, J.-P. (2008) Geomorphology 102, 343-367. [15] Scholten, F. et al. (2005) PE&RS, 71, 1143-1152. [16] Gwinner, K. et al. (2005) PFG, 5/2005, 387-394. [17] Parker, G. et al. (1998) J. Hydraul. Engin., 124, 985-995.

An Examination of the Effect of Boundary Layer Ingestion on Turboelectric Distributed Propulsion Systems

NASA Technical Reports Server (NTRS)

Felder, James L.; Kim, Huyn Dae; Brown, Gerald V.; Chu, Julio

2011-01-01

A Turboelectric Distributed Propulsion (TeDP) system differs from other propulsion systems by the use of electrical power to transmit power from the turbine to the fan. Electrical power can be efficiently transmitted over longer distances and with complex topologies. Also the use of power inverters allows the generator and motors speeds to be independent of one another. This decoupling allows the aircraft designer to place the core engines and the fans in locations most advantageous for each. The result can be very different installation environments for the different devices. Thus the installation effects on this system can be quite different than conventional turbofans where the fan and core both see the same installed environments. This paper examines a propulsion system consisting of two superconducting generators, each driven by a turboshaft engine located so that their inlets ingest freestream air, superconducting electrical transmission lines, and an array of superconducting motor driven fan positioned across the upper/rear fuselage area of a hybrid wing body aircraft in a continuous nacelle that ingests all of the upper fuselage boundary layer. The effect of ingesting the boundary layer on the design of the system with a range of design pressure ratios is examined. Also the impact of ingesting the boundary layer on off-design performance is examined. The results show that when examining different design fan pressure ratios it is important to recalculate of the boundary layer mass-average Pt and MN up the height for each inlet height during convergence of the design point for each fan design pressure ratio examined. Correct estimation of off-design performance is dependent on the height of the column of air measured from the aircraft surface immediately prior to any external diffusion that will flow through the fan propulsors. The mass-averaged Pt and MN calculated for this column of air determine the Pt and MN seen by the propulsor inlet. Since the height of this column will change as the amount of air passing through the fans change as the propulsion system is throttled, and since the mass-average Pt and MN varies by height, this capture height must be recalculated as the airflow through the propulsor is varied as the off-design performance point is converged.

Effects of inflow distortion profiles on fan tone noise calculated using a 3-D theory

NASA Technical Reports Server (NTRS)

Kobayashi, H.; Groeneweg, J. F.

1979-01-01

Calculations of the fan tone acoustic power and modal structure generated by complex distortions in axial inflow velocity are presented. The model used treats the motor as a rotating three-dimensional cascade and calculates the acoustic field from the distortion-produced dipole distribution on the blades including noncompact source effects. Radial and circumferential distortion shapes are synthesized from Fourier-Bessel components representing individual distortion modes. The relation between individual distortion modes and the generated acoustic modes is examined for particular distortion cases. Comparisons between theoretical and experimental results for distortions produced by wakes from upstream radial rods show that the analysis is a good predictor of acoustic power dependence on disturbance strength.

Sea fan immunity and disease is influenced by metal pollution, host demography, and multiple stressors

NASA Astrophysics Data System (ADS)

Tracy, A. M.; Weil, E.; Harvell, C. D.

2016-02-01

Organisms in natural populations experience an onslaught of stressful conditions that may compromise their ability to fight pathogens, particularly if multiple stressors impact a host at the same time. Environmental stressors can also influence the pathogens. Despite the clear importance of environmental factors for coral host-pathogen interactions and the potential for population-level consequences, there is relatively little research to date on multiple stressors. The population of Caribbean sea fans, Gorgonia ventalina, in Parguera, Puerto Rico is a tractable system in which to study the effects of multiple stressors on two pathogens. Sea fans are dominant members of reefs that provide food and habitat for diverse reef inhabitants. In addition, there is already a foundation of research on sea fan disease and immunity. We first conducted field surveys of 15 sites to assess the effects of demographic and environmental factors on the prevalence and severity of multifocal purple spots (MFPS) and a Labyrinthulid stramenopile pathogen, as well as the host's cellular immune response to each pathogen. We complemented the field survey with a fully factorial, clonally replicated experiment on the separate and combined effects of thermal stress and copper pollution on both the host and the pathogen. Although water quality has been linked to coral disease, there are no studies investigating the role of metal or chemical pollutants, which are high at some of our study sites. Preliminary results show that the sea fan immune response to the Labyrinthulid depends on interactive effects of copper and thermal stress. The field survey identifies colony size as the main driver of MFPS. This in-depth perspective on sea fan disease speaks to the immune capabilities of cnidarians, highlights factors that modify those capabilities, and reflects the complex interaction of host, pathogens, and environment in this ecologically important coral.

Submarine fans: Characteristics, models, classification, and reservoir potential

NASA Astrophysics Data System (ADS)

Shanmugam, G.; Moiola, R. J.

1988-02-01

Submarine-fan sequences are important hydrocarbon reservoirs throughout the world. Submarine-fan sequences may be interpreted from bed-thickness trends, turbidite facies associations, log motifs, and seismic-reflection profiles. Turbidites occurring predominantly in channels and lobes (or sheet sands) constitute the major portion of submarine-fan sequences. Thinning- and thickening-upward trends are suggestive of channel and lobe deposition, respectively. Mounded seismic reflections are commonly indicative of lower-fan depositional lobes. Fan models are discussed in terms of modern and ancient fans, attached and detached lobes, highly efficient and poorly efficient systems, and transverse and longitudinal fans. In general, depositional lobes are considered to be attached to feeder channels. Submarine fans can be classified into four types based on their tectonic settings: (1) immature passive-margin fans (North Sea type); (2) mature passive-margin fans (Atlantic type); (3) active-margin fans (Pacific type); and (4) mixed-setting fans. Immature passive-margin fans (e.g., Balder, North Sea), and active-margin fans (e.g., Navy, Pacific Ocean) are usually small, sand-rich, and possess well developed lobes. Mature passive-margin fans (e.g., Amazon, Atlantic Ocean) are large, mud-rich, and do not develop typical lobes. However, sheet sands are common in the lower-fan regions of mature passive-margin fans. Mixed-setting fans display characteristics of either Atlantic type (e.g., Bengal, Bay of Bengal), or Pacific type (Orinoco, Caribbean), or both. Conventional channel-lobe models may not be applicable to fans associated with mature passive margins. Submarine fans develop primarily during periods of low sea level on both active- and passive-margin settings. Consequently, hydrocarbon-bearing fan sequences are associated generally with global lowstands of sea level. Channel-fill sandstones in most tectonic settings are potential reservoirs. Lobes exhibit the most favorable reservoir quality in terms of sand content, lateral continuity, and porosity development. Lower-fan sheet sands may also make good reservoirs. Quartz-rich sandstones of mature passive-margin fans are most likely to preserve depositional porosity, whereas lithic sandstones of active-margin fans may not.

Relative Abundance and Diversity of Bacterial Methanotrophs at the Oxic-Anoxic Interface of the Congo Deep-Sea Fan.

PubMed

Bessette, Sandrine; Moalic, Yann; Gautey, Sébastien; Lesongeur, Françoise; Godfroy, Anne; Toffin, Laurent

2017-01-01

Sitting at ∼5,000 m water depth on the Congo-Angola margin and ∼760 km offshore of the West African coast, the recent lobe complex of the Congo deep-sea fan receives large amounts of fluvial sediments (3-5% organic carbon). This organic-rich sedimentation area harbors habitats with chemosynthetic communities similar to those of cold seeps. In this study, we investigated relative abundance, diversity and distribution of aerobic methane-oxidizing bacteria (MOB) communities at the oxic-anoxic interface of sedimentary habitats by using fluorescence in situ hybridization and comparative sequence analysis of particulate mono-oxygenase ( pmoA ) genes. Our findings revealed that sedimentary habitats of the recent lobe complex hosted type I and type II MOB cells and comparisons of pmoA community compositions showed variations among the different organic-rich habitats. Furthermore, the pmoA lineages were taxonomically more diverse compared to methane seep environments and were related to those found at cold seeps. Surprisingly, MOB phylogenetic lineages typical of terrestrial environments were observed at such water depth. In contrast, MOB cells or pmoA sequences were not detected at the previous lobe complex that is disconnected from the Congo River inputs.

Stratigraphic Evolution of Brazos-Trinity Basin IV, Western Gulf of Mexico: Preliminary Results of IODP Expedition 308

NASA Astrophysics Data System (ADS)

Pirmez, C.; Behrmann, J.; Flemings, P. B.; John, C.

2005-12-01

IODP Expedition 308 drilled three sites across Brazos-Trinity Basin IV, at the terminal end of a system of four salt-withdrawal intra-slope basins offshore Texas. A 175 m thick succession of sand-rich turbidite fans, mass-transport deposits and hemipelagic sediments was deposited within the last ~120 ka in Basin IV, as recorded at Site U1320. Pre-fan deposits dating back to MIS 6 form a conformable succession of laminated and bioturbated clays, deposited from distal turbidity currents and/or river plumes. The pre-fan succession is capped by a hemipelagic clay interpreted to represent the high stand of sea level during MIS 5e. The basal turbidite deposits in the basin are mud-rich, with the exception of the very first turbidity currents to enter the basin. This initial pulse, possibly derived from failure of older shelf edge deposits, accumulated an ~8 m thick sand-rich interval. A pause in turbidity current influx lasted 30 to 40 kyrs, beginning a few thousand years before ash layer Y8 dated at 84 ka and the Emiliana huxleyi acme. During MIS 3 to MIS 2 sand-rich fans containing 5-25 m thick packets of very fine to lower medium sand beds accumulated up to 130 m of sediments. A 2-3 m thick microfossil-rich clay marks the end of turbidity current influx into the basin during the Holocene. The sedimentary record of Brazos-Trinity Basin IV shows that the accumulation of turbidites in the terminal end of this source to sink depositional system reflects a complex interaction between the availability of material and the initiation of flows at the source near the shelf edge, the interaction of turbidity currents with complex slope topography, and the effects of salt tectonics and flow processes on modifying this topography. The initial results indicate that sealevel changes alone cannot explain the sedimentation patterns observed in the basin.

Polyphase thrust tectonic in the Barberton greenstone belt

NASA Technical Reports Server (NTRS)

Paris, I. A.

1986-01-01

In the circa 3.5 by-old Barberton greenstone belt, the supracrustal rocks form a thick and strongly deformed thrust complex. Structural studies in the southern part of the belt have shown that 2 separate phases of over-thrusting (D sub 1 and D sub 2) successively dismembered the original stratigraphy. Thrust nappes were subsequently refolded during later deformations (D sub 3 and D sub 4). This report deals with the second thrusting event which, in the study region appears to be dominant, and (unlike the earlier thrusting), affects the entire supracrustal pile. The supracrustal rocks form a predominantly NE/SW oriented, SE dipping tectonic fan (the D sub 2 fan) in which tectonic slices of ophiolitic-like rocks are interleaved with younger sedimentary sequences of the Diepgezet and malalotcha groups. Structural and sedimentological data indicate that the D sub 2 tectonic fan was formed during a prolonged, multi-stage regional horizontal shortening event during which several types of internal deformation mechanisms were successively and/or simultaneously active. Movement appears to have been predominantly to the NW and to the N. During D sub 2, periods of quiescence and sedimentation followed periods of thrust propagation. Although the exact kinematics which led to the formation of this fan is not yet known, paleoenvironmental interpretations together with structural data suggest that D sub 2 was probably related to (an) Archean collision(s).

China Report Economic Affairs Energy: Status and Development 38.

DTIC Science & Technology

1985-04-29

Measures To Convert From Oil to Coal Showing Results (Li Renjun; NENG YUAN [JOURNAL OF ENERGY] No 6, 25 Dec 84).... • ••• 61 Briefs 67 New Hebei...Coal Mine ’" Liaoning Local Colliery Growth ’ OIL AND GAS More Onshore Oil and Gas Reserves Verified CXINHUA, 12 Apr 85)......... •. • • bb New...Well Gushes Oil in South China Sea CXINHUA, 12 Apr 85) • • • ■ * • • by Daqing Fields Produce 52.3 Million Tons in 1984 _ CMa Zhiping; CHINA

Turbofan gas turbine engine with variable fan outlet guide vanes

NASA Technical Reports Server (NTRS)

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

Radially leaned outlet guide vanes for fan source noise reduction

NASA Technical Reports Server (NTRS)

Kazin, S. B.

1973-01-01

Two quiet engine program half scale fans one with a subsonic and the other with a supersonic fan tip speed at takeoff were run with 30 degree leaned and radial outlet guide vanes. Acoustic data at takeoff fan speed on the subsonic tip speed fan showed decreases in 200-foot sideline noise of from 1 to 2 PNdb. The supersonic tip speed fan a takeoff fan speed, however, showed noise increases of up 3 PNdb and a decrease in fan efficiency. At approach fan speed, the subsonic tip speed fan showed a noise decrease of 2.3 PNdb at the 200-foot sideline maximum angle and an increase in efficiency. The supersonic tip speed fan showed noise increase of 3.5 PNdb and no change in efficiency. The decrease in fan efficiency and the nature of the noise increase largely high frequency broadband noise lead to the speculation that an aerodynamic problem occurred.

Depositional environment and sedimentary of the basinal sediments in the Eibiswalder Bucht (Radl Formation and Lower Eibiswald Beds), Miocene Western Styrian Basin, Austria

NASA Astrophysics Data System (ADS)

Stingl, K.

1994-12-01

The Eibiswald Bucht is a small subbasin of the Western Styrian Basin exposing sediments of Lower Miocene age. In the past the entire sequence exposed in the Eibiswalder Bucht has been interpreted as being of fluvial/lacustrine origin; here, results are presented of detailed sedimentological investigations that lead to a revision of this concept. The lowermost siliciclastic sedimentary unit of the Eibiswalder Bucht sequence is the Radl Formation. It is overlain by the Eibiswald Beds, which are subdivided into the Lower, Middle and Upper Eibiswald Beds. The Radl Formation and the Lower Eibiswald Beds are interpreted as a fan delta complex deposited along NNW-SSE striking faults. Based on the sedimentary facies this fan delta can be subdivided into a subaerial alluvial fan facies group, a proximal delta facies group and a distal delta/prodelta facies group. The Radl Formation comprises the alluvial fan and proximal delta facies groups, the Lower Eibiswald Beds the distal delta/prodelta facies group. The alluvial fan and the proximal delta consist of diverse deposits of gravelly flows. The distal delta/prodelta consists of wave-reworked, bioturbated, low density turbidites intercalated with minor gravelly mass flows. The prodelta can be regarded as as the basin facies of the small and shallow Eibiswalder Bucht, where marine conditions prevailed. The basin was probably in part connected with the Eastern Styrian Basin, the contemporary depositional environment of the Styrian Schlier (mainly turbiditic marine offshore sediments in the Eastern Styrian Basin). Analysis of the clast composition, in conjunction with the paleotransport direction of the coarse delta mass flows of the Radl Formation, shows that the source rocks were exclusively crystalline rocks ranging from greenschists to eclogites.

Modeling 3-D permeability distribution in alluvial fans using facies architecture and geophysical acquisitions

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

Zhu, Lin; Gong, Huili; Dai, Zhenxue

Alluvial fans are highly heterogeneous in hydraulic properties due to complex depositional processes, which make it difficult to characterize the spatial distribution of the hydraulic conductivity ( K). An original methodology is developed to identify the spatial statistical parameters (mean, variance, correlation range) of the hydraulic conductivity in a three-dimensional (3-D) setting by using geological and geophysical data. More specifically, a large number of inexpensive vertical electric soundings are integrated with a facies model developed from borehole lithologic data to simulate the log 10( K) continuous distributions in multiple-zone heterogeneous alluvial megafans. The Chaobai River alluvial fan in the Beijing Plain,more » China, is used as an example to test the proposed approach. Due to the non-stationary property of the K distribution in the alluvial fan, a multiple-zone parameterization approach is applied to analyze the conductivity statistical properties of different hydrofacies in the various zones. The composite variance in each zone is computed to describe the evolution of the conductivity along the flow direction. Consistently with the scales of the sedimentary transport energy, the results show that conductivity variances of fine sand, medium-coarse sand, and gravel decrease from the upper (zone 1) to the lower (zone 3) portion along the flow direction. In zone 1, sediments were moved by higher-energy flooding, which induces poor sorting and larger conductivity variances. The composite variance confirms this feature with statistically different facies from zone 1 to zone 3. Lastly, the results of this study provide insights to improve our understanding on conductivity heterogeneity and a method for characterizing the spatial distribution of  K in alluvial fans.« less

Modeling 3-D permeability distribution in alluvial fans using facies architecture and geophysical acquisitions

DOE PAGES

Zhu, Lin; Gong, Huili; Dai, Zhenxue; ...

2017-02-03

Alluvial fans are highly heterogeneous in hydraulic properties due to complex depositional processes, which make it difficult to characterize the spatial distribution of the hydraulic conductivity ( K). An original methodology is developed to identify the spatial statistical parameters (mean, variance, correlation range) of the hydraulic conductivity in a three-dimensional (3-D) setting by using geological and geophysical data. More specifically, a large number of inexpensive vertical electric soundings are integrated with a facies model developed from borehole lithologic data to simulate the log 10( K) continuous distributions in multiple-zone heterogeneous alluvial megafans. The Chaobai River alluvial fan in the Beijing Plain,more » China, is used as an example to test the proposed approach. Due to the non-stationary property of the K distribution in the alluvial fan, a multiple-zone parameterization approach is applied to analyze the conductivity statistical properties of different hydrofacies in the various zones. The composite variance in each zone is computed to describe the evolution of the conductivity along the flow direction. Consistently with the scales of the sedimentary transport energy, the results show that conductivity variances of fine sand, medium-coarse sand, and gravel decrease from the upper (zone 1) to the lower (zone 3) portion along the flow direction. In zone 1, sediments were moved by higher-energy flooding, which induces poor sorting and larger conductivity variances. The composite variance confirms this feature with statistically different facies from zone 1 to zone 3. Lastly, the results of this study provide insights to improve our understanding on conductivity heterogeneity and a method for characterizing the spatial distribution of  K in alluvial fans.« less

Using luminescence dating of coarse matrix material to estimate the slip rate of the Astaneh fault, Iran

USGS Publications Warehouse

Rizza, M.; Mahan, S.; Ritz, J.-F.; Nazari, H.; Hollingsworth, J.; Salamati, R.

2011-01-01

In this paper, we present optically and infrared stimulated luminescence (OSL and IRSL) ages for four samples from alluvial fan surfaces in the Astaneh Valley. This valley is located in the north-east part of the Alborz range in Iran. Our morphologic interpretations recognize at least three generations of fans in the study area, all of which have been displaced along the left-lateral strike-slip Astaneh fault. Because of the dry, loose, and sometimes complex juxtaposition of the target sediments, we collected the samples in total darkness beneath dark plastic layers placed atop the pit openings. Luminescence ages of the fans are ???55 ka, ???32 ka and ???16 ka. These ages are concurrent with periods of loess deposition and wet climatic conditions previously recorded in the Arabia-Iranian region. They allow estimation of a horizontal slip rate of ???2 mm/yr along the Astaneh fault, which is consistent with additional slip rates determined for the Holocene period along faults further west of the Astaneh fault. ?? 2011 Elsevier B.V.

PSP Measurement of Stator Vane Surface Pressures in a High Speed Fan

NASA Technical Reports Server (NTRS)

Lepicovsky, Jan

1998-01-01

This paper presents measurements of static pressures on the stator vane suction side of a high-speed single stage fan using the technique of pressure sensitive paint (PSP). The paper illustrates development in application of the relatively new experimental technique to the complex environment of internal flows in turbomachines. First, there is a short explanation of the physics of the PSP technique and a discussion of calibration methods for pressure sensitive paint in the turbomachinery environment. A description of the image conversion process follows. The recorded image of the stator vane pressure field is skewed due to the limited optical access and must be converted to the meridional plane projection for comparison with analytical predictions. The experimental results for seven operating conditions along an off-design rotational speed line are shown in a concise form, including performance map points, mindspan static tap pressure distributions, and vane suction side pressure fields. Then, a comparison between static tap and pressure sensitive paint data is discussed. Finally, the paper lists shortcomings of the pressure sensitive paint technology and lessons learned in this high-speed fan application.

Design, fabrication and acoustic tests of a 36 inch (0.914 meter) statorless turbotip fan

NASA Technical Reports Server (NTRS)

Smith, E. G.; Stempert, D. L.; Uhl, W. R.

1975-01-01

The LF336/E is a 36 inch (0.914 meter) diameter fan designed to operate in a rotor-alone configuration. Design features required for modification of the existing LF336/A rotor-stator fan into the LF336/E statorless fan configuration are discussed. Tests of the statorless fan identified an aerodynamic performance deficiency due to inaccurate accounting of the fan exit swirl during the aerodynamic design. This performance deficiency, related to fan exit static pressure levels, produced about a 20 percent thrust loss. A study was then conducted for further evaluation of the fan exit flow fields typical of statorless fan systems. This study showed that through proper selection of fan design variables such as pressure ratio, radius ratio, and swirl distributions, performance of a statorless fan configuration could be improved with levels of thrust approaching the conventional rotor-stator fan system. Acoustic measurements were taken for the statorless fan system at both GE and NASA, and when compared to other lift fan systems, showed noise levels comparable to the quietest lift fan configuration which included rotor-stator spacing and acoustic treatment. The statorless fan system was also used to determine effects of rotor leading edge serrations on noise generations. A cascade test program identified the serration geometry based on minimum pressure losses, wake turbulence levels and noise generations.

Fan-shaped antennas: Realization of wideband characteristics and generation of stop bands

NASA Astrophysics Data System (ADS)

Nakano, H.; Morishita, K.; Iitsuka, Y.; Mimaki, H.; Yoshida, T.; Yamauchi, J.

2008-08-01

This paper presents four fan-shaped antennas: U.S.-FAN, CROSS-FAN, CROSS-FAN-W, and CROSS-FAN-S. Each of these antennas stands upright above a ground plane, and has edges expressed by an exponential function and a circle function. The four antennas are investigated using frequencies from 1.5 GHz to 11 GHz. The CROSS-FAN is found to have a lower VSWR over a wide frequency band compared to the U.S.-FAN. The CROSS-FAN-W and CROSS-FAN-S are modified versions of the CROSS-FAN, each designed to have a stop band (a high VSWR frequency range) for interference cancellation. The stop band for the CROSS-FAN-W is controlled by a wire (total length 4Lwire) that connects the fan-shaped elements. The center frequency of the stop band fstop is close to the frequency corresponding to a wire segment length Lwire of half the wavelength. It is also found that the stop band in the CROSS-FAN-S can be controlled by four slots, one cut into each of the fan-shaped elements. The center frequency of the stop band fstop is close to the frequency corresponding to a slot length Lslot of one-quarter of the wavelength. Experimental work is performed to confirm the theoretical results, using the CROSS-FAN-S.

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.

Smart Fan Modules And System

DOEpatents

Cipolla, Thomas M.; Kaufman, Richard I.; Mok, Lawrence S.

2003-07-15

A fan module including: two or more individual fans, each fan having an air movement means and a motor engaged with the air movement means for accelerating air entering each of the two or more individual fans; a temperature sensor for sensing a temperature associated with the two or more fans and for outputting a first signal corresponding to the temperature; rotational speed sensor for outputting a second signal corresponding to a rotational speed of each of the two or more fans; and a processor for receiving the first and second signals and controlling the two or more individual fans based on the first and second signals. A fan module including: two or more individual fans, each fan having an air movement means and a motor engaged with the air movement means for accelerating air entering each of the two or more individual fans; a temperature sensor for sensing a temperature associated with the two or more fans and for outputting a first signal corresponding to the temperature; rotational speed sensor for outputting a second signal corresponding to a rotational speed of each of the two or more fans; and a processor for receiving the first and second signals and controlling the two or more individual fans based on the first and second signals.

Octopamine and tyramine modulate the thermoregulatory fanning response in honey bees (Apis mellifera L.)

USDA-ARS?s Scientific Manuscript database

Biogenic amines regulate the proximate mechanisms underlying most behavior, including those that contribute to the overall success of complex societies. For honey bees one critical set of behaviors contributing to the welfare of a colony are involved with nest thermoregulation. Worker honey bees co...

Comparison of Far-Field Noise for Three Significantly Different Model Turbofans

NASA Technical Reports Server (NTRS)

Woodward, Richard P.

2008-01-01

Far-field noise sound power level (PWL) spectra and overall sound pressure level (OASPL) directivities were compared for three significantly different model fan stages which were tested in the NASA Glenn 9x15 Low Speed Wind Tunnel. The test fans included the Advanced Ducted Propulsor (ADP) Fan1, the baseline Source Diagnostic Test (SDT) fan, and the Quiet High Speed Fan2 (QHSF2) These fans had design rotor tangential tip speeds from 840 to 1474 ft/s and stage pressure ratios from 1.29 to 1.82. Additional parameters included rotor-stator spacing, stator sweep, and downstream support struts. Acoustic comparison points were selected on the basis of stage thrust. Acoustic results for the low tip speed/low pressure ratio fan (ADP Fan1) were thrust-adjusted to show how a geometrically-scaled version of this fan might compare at the higher design thrust levels of the other two fans. Lowest noise levels were typically observed for ADP Fan1 (which had a radial stator) and for the intermediate tip speed fan (Source Diagnostics Test, SDT, R4 rotor) with a swept stator. Projected noise levels for the ADP fan to the SDT swept stator configuration at design point conditions showed the fans to have similar noise levels. However, it is possible that the ADP fan could be 2 to 3 dB quieter with incorporation of a swept stator. Benefits of a scaled ADP fan include avoidance of multiple pure tones associated with transonic and higher blade tip speeds. Penalties of a larger size ADP fan would include increased nacelle size and drag.

Comparison of Far-field Noise for Three Significantly Different Model Turbofans

NASA Technical Reports Server (NTRS)

Woodward, Richard P.

2008-01-01

Far-field noise sound power level (PWL) spectra and overall sound pressure level (OASPL) directivities were compared for three significantly different model fan stages which were tested in the NASA Glenn 9 15 Low Speed Wind Tunnel. The test fans included the Advanced Ducted Propulsor (ADP) Fan1, the baseline Source Diagnostic Test (SDT) fan, and the Quiet High Speed Fan2 (QHSF2). These fans had design rotor tangential tip speeds from 840 to 1474 ft/s and stage pressure ratios from 1.29 to 1.82. Additional parameters included rotor-stator spacing, stator sweep, and downstream support struts. Acoustic comparison points were selected on the basis of stage thrust. Acoustic results for the low tip speed/low pressure ratio fan (ADP Fan1) were thrust-adjusted to show how a geometrically-scaled version of this fan might compare at the higher design thrust levels of the other two fans. Lowest noise levels were typically observed for ADP Fan1 (which had a radial stator) and for the intermediate tip speed fan (Source Diagnostics Test, SDT, R4 rotor) with a swept stator. Projected noise levels for the ADP fan to the SDT swept stator configuration at design point conditions showed the fans to have similar noise levels. However, it is possible that the ADP fan could be 2 to 3 dB quieter with incorporation of a swept stator. Benefits of a scaled ADP fan include avoidance of multiple pure tones associated with transonic and higher blade tip speeds. Penalties of a larger size ADP fan would include increased nacelle size and drag.

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.

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.

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.

Primary structure and subcellular localization of two fimbrial subunit-like proteins involved in the biosynthesis of K99 fibrillae.

PubMed

Roosendaal, E; Jacobs, A A; Rathman, P; Sondermeyer, C; Stegehuis, F; Oudega, B; de Graaf, F K

1987-09-01

Analysis of the nucleotide sequence of the distal part of the fan gene cluster encoding the proteins involved in the biosynthesis of the fibrillar adhesin, K99, revealed the presence of two structural genes, fanG and fanH. The amino acid sequence of the gene products (FanG and FanH) showed significant homology to the amino acid sequence of the fibrillar subunit protein (FanC). Introduction of a site-specific frameshift mutation in fanG or fanH resulted in a simultaneous decrease in fibrillae production and adhesive capacity. Analysis of subcellular fractions showed that, in contrast to the K99 fibrillar subunit (FanC), both the FanH and the FanG protein were loosely associated with the outer membrane, possibly on the periplasmic side, but were not components of the fimbriae themselves.

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.

Comparison of BacT/Alert FAN and FAN Plus Bottles with Conventional Medium for Culturing Cerebrospinal Fluid.

PubMed

Yoo, In Young; Chun, Sejong; Song, Dong Joon; Huh, Hee Jae; Lee, Nam Yong

2016-11-01

We compared the BacT/Alert system FAN and FAN Plus media to conventional media for culturing cerebrospinal fluid (CSF) with 2,545 samples. FAN/FAN Plus bottles showed better performance for isolating microorganisms in CSF than conventional media (positive rate, 7.2% [182/2,545] versus 3.1% [80/2,545]). The incremental recovery rate of Cryptococcus neoformans from FAN Plus bottles was higher than that from FAN bottles. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Effects of perforation number of blade on aerodynamic performance of dual-rotor small axial flow fans

NASA Astrophysics Data System (ADS)

Hu, Yongjun; Wang, Yanping; Li, Guoqi; Jin, Yingzi; Setoguchi, Toshiaki; Kim, Heuy Dong

2015-04-01

Compared with single rotor small axial flow fans, dual-rotor small axial flow fans is better regarding the static characteristics. But the aerodynamic noise of dual-rotor small axial flow fans is worse than that of single rotor small axial flow fans. In order to improve aerodynamic noise of dual-rotor small axial flow fans, the pre-stage blades with different perforation numbers are designed in this research. The RANS equations and the standard k-ɛ turbulence model as well as the FW-H noise model are used to simulate the flow field within the fan. Then, the aerodynamic performance of the fans with different perforation number is compared and analyzed. The results show that: (1) Compared to the prototype fan, the noise of fans with perforation blades is reduced. Additionally, the noise of the fans decreases with the increase of the number of perforations. (2) The vorticity value in the trailing edge of the pre-stage blades of perforated fans is reduced. It is found that the vorticity value in the trailing edge of the pre-stage blades decreases with the increase of the number of perforations. (3) Compared to the prototype fan, the total pressure rising and efficiency of the fans with perforation blades drop slightly.

Using Synthetic Aperture Radar data of terrestrial analogs to test for alluvial fan formation mechanisms on Titan

NASA Astrophysics Data System (ADS)

Cartwright, R. J.; Burr, D. M.

2017-03-01

Landforms on Titan include features hypothesized to be alluvial fans. Terrestrial alluvial fans form via two processes: fluid-gravity flows (sheetfloods) and sediment-gravity flows (debris flows). Along the Panamint Mountain Range in Death Valley, California, USA, seven fans formed primarily by debris flows are located adjacent to seven fans formed primarily by sheetfloods. The causal difference between these two groupings stems from their catchment lithologies; the debris flow fan catchments are clay-rich and relatively sand-poor, and the sheetflood fan catchments are clay-poor and sand-rich. On Titan, the low and mid latitudes are dominated by sand seas, demonstrating that sand is available for transport. At high latitudes, these sand seas are absent, suggesting that transportable sand is scarce. Based on the sedimentology of the two Panamint Range fan types, we hypothesize that possible fans at lower latitudes on Titan are formed by sheetfloods, whereas those at higher latitudes formed primarily by debris flows. To test these hypotheses, we measured and analyzed the mean normalized radar cross sections (σ°) and changes in σ° with downfan distance for debris flow and sheetflood fans along the Panamint Range. We then compared the results with the same measurements for possible fans on Titan. We find that, in the Panamint Range, debris flow fans are brighter than sheetflood fans and have greater change in σ° with downfan distance, and that on Titan, low-latitude possible fans are likewise brighter than the fans at high latitudes with greater change in σ° with downfan distance. Consequently, our findings suggest that low-latitude possible fans on Titan are formed primarily by debris flows, whereas high-latitude possible fans on Titan are formed primarily by sheetfloods. Thus, our results do not support our hypotheses. Scenarios to explain these results include: (1) high-latitude possible fans are dominated by radar-dark debris flow deposits, (2) low- and mid-latitude possible fans are dominated by radar-bright sheetflood deposits, (3) sand-sized sediments were relatively scarce at the time of low- and mid-latitude possible fan formation, (4) bedrock composition varies as a function of latitude on Titan, (5) alluvial fans form differently on Titan because of the lower gravity conditions, and (6) fan-like features may result from non-alluvial processes, such as form distributary fluvial systems on Earth.

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 formed around the time of the Noachian-Hesperian boundary. We infer that these fans formed during an episode of enhanced precipitation (probably snow) and runoff, which exhibited both sudden onset and termination.

Evaluation of the Appropriate Washout Period Following Fan Therapy for Dyspnea in Patients With Advanced Cancer: A Pilot Study.

PubMed

Kako, Jun; Morita, Tatsuya; Yamaguchi, Takuhiro; Sekimoto, Asuko; Kobayashi, Masamitsu; Kinoshita, Hiroya; Ogawa, Asao; Zenda, Sadamoto; Uchitomi, Yosuke; Inoguchi, Hironobu; Matsushima, Eisuke

2018-02-01

To clarify the duration required for dyspnea to return to baseline severity after fan therapy, to evaluate whether fan-to-legs therapy or no fan therapy would be a suitable control therapy, and to investigate changes in patients' face surface temperature after fan therapy. In this pilot study, all participants received 3 interventions in the following order: no fan, fan to legs, and fan to face. Participants used a fan for 5 minutes, and they scored their dyspnea at 10-minute intervals for 60 minutes or until the score had returned to its baseline value, whichever occurred first. Nine patients with advanced cancer admitted to a palliative care unit were included; they had dyspnea at rest and rated its severity as at least 3 points on a 0- to 10-point numerical rating scale. Descriptive statistics and the Wilcoxon signed rank test were used to analyze the data. All patients completed the study. Of the 9 participants, 6 experienced a clinical benefit from using a fan to their faces. Of these patients, only 2 participants' (2 of 6) dyspnea scores returned to baseline by the end of the 60-minute assessment period after exposure to fan-to-face therapy. In fan-to-legs and no fan settings, there was no change in the dyspnea scores. There were significant differences between the baseline face surface temperature and that after fan-to-face and fan-to-legs settings. When using a crossover design to investigate the effect of fan therapy on dyspnea, 1 hour is an insufficient washout period.

30 CFR 57.8534 - Shutdown or failure of auxiliary fans.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shutdown or failure of auxiliary fans. 57.8534... Ventilation Underground Only § 57.8534 Shutdown or failure of auxiliary fans. (a) Auxiliary fans installed and... fan maintenance or fan adjustments where air quality is maintained in compliance with the applicable...

The development of a laterally confined laboratory fan delta under sediment supply reduction

NASA Astrophysics Data System (ADS)

Zhang, Xiaofeng; Wang, Siqiang; Wu, Xi; Xu, Shun; Li, Zhangyong

2016-03-01

In previous fan delta experiments, the effect of lateral confinement was generally ignored as these fans were usually unconfined with semiconical geometries. However, in gorge areas, fan development is usually laterally confined by valley walls. This study investigates autogenic processes of fan deltas in a laterally confined experimental tank. The experiment is divided into three phases. The sediment supply is held constant within each phase, so the autogenic processes of the fan are separated from the allogenic forcings. Results indicate that laterally confined fan deltas have higher progradation and aggradation potential, more regular channel braiding, and more even transverse sedimentation than unconfined fans. Besides, responses of fan deltas to sediment supply reduction are investigated in this research. At the initiation of the second and third phases, sediment feed rates are instantaneously reduced so that the allogenic forcings are predominant. Observations show that under sediment supply reduction, channelization on fan deltas are more pronounced and durations of the fluvial cycles are longer. The adjustment of fan morphology becomes slower as the self-regulation capacity of the fan decreases with reduced sediment supply.

30 CFR 57.4504 - Fan installations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... for main and booster fans, and air ducts connecting main fans to underground openings shall be constructed of noncombustible materials. (b) Areas within 25 feet of main fans or booster fans shall be free...

30 CFR 57.4504 - Fan installations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... for main and booster fans, and air ducts connecting main fans to underground openings shall be constructed of noncombustible materials. (b) Areas within 25 feet of main fans or booster fans shall be free...

30 CFR 57.4504 - Fan installations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... for main and booster fans, and air ducts connecting main fans to underground openings shall be constructed of noncombustible materials. (b) Areas within 25 feet of main fans or booster fans shall be free...

30 CFR 57.4504 - Fan installations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... for main and booster fans, and air ducts connecting main fans to underground openings shall be constructed of noncombustible materials. (b) Areas within 25 feet of main fans or booster fans shall be free...

Fan Noise Source Diagnostic Test: Rotor Alone Aerodynamic Performance Results

NASA Technical Reports Server (NTRS)

Hughes, Christopher E.; Jeracki, Robert J.; Woodward, Richard P.; Miller, Christopher J.

2005-01-01

The aerodynamic performance of an isolated fan or rotor alone model was measured in the NASA Glenn Research Center 9- by 15- Foot Low Speed Wind Tunnel as part of the Fan Broadband Source Diagnostic Test conducted at NASA Glenn. The Source Diagnostic Test was conducted to identify the noise sources within a wind tunnel scale model of a turbofan engine and quantify their contribution to the overall system noise level. The fan was part of a 1/5th scale model representation of the bypass stage of a current technology turbofan engine. For the rotor alone testing, the fan and nacelle, including the inlet, external cowl, and fixed area fan exit nozzle, were modeled in the test hardware; the internal outlet guide vanes located behind the fan were removed. Without the outlet guide vanes, the velocity at the nozzle exit changes significantly, thereby affecting the fan performance. As part of the investigation, variations in the fan nozzle area were tested in order to match as closely as possible the rotor alone performance with the fan performance obtained with the outlet guide vanes installed. The fan operating performance was determined using fixed pressure/temperature combination rakes and the corrected weight flow. The performance results indicate that a suitable nozzle exit was achieved to be able to closely match the rotor alone and fan/outlet guide vane configuration performance on the sea level operating line. A small shift in the slope of the sea level operating line was measured, which resulted in a slightly higher rotor alone fan pressure ratio at take-off conditions, matched fan performance at cutback conditions, and a slightly lower rotor alone fan pressure ratio at approach conditions. However, the small differences in fan performance at all fan conditions were considered too small to affect the fan acoustic performance.

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 fan-impeller/diffuser section in water was observed with a flow visualization technique using a shear-thickening dye (in addition to a conventional dye). Full dynamic similarity was maintained between RVAC operation in water as when operated in air. Recommendations are provided both for further investigation of critical flow regions with more sophisticated measurement methods and for improved fan-scroll design to reduce possible aeroacoustic noise with improved aerodynamic performance.

Controls on alluvial fans morphology

NASA Astrophysics Data System (ADS)

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

2017-12-01

Using laboratory experiments, we investigate the influence of water and sediment discharges on the morphology of an alluvial fan. In our flume, a single-thread laminar river deposits corundum sand (0.4 mm) into a conical fan. We record the fan progradation with top-view images, and measure its shape using the deformation of a Moiré pattern. The fan remains virtually self-affine as it grows, with a nearly constant slope. We find that, when the sediment discharge is small, the longitudinal slope of the fan remains close to that of a river at the threshold for sediment transport. A higher sediment discharge causes the fan's slope to depart from the threshold value. Due to the downstream decrease of the sediment load, this slope gets shallower towards the fan's toe. This mechanism generates a slightly concave fan profile. This suggests that the proximal slope of an alluvial fan could be a proxy for the sediment flux that feeds the fan.Finally, we discuss the applicability of these results to natural systems.

30 CFR 75.302 - Main mine fans.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ventilated by one or more main mine fans. Booster fans shall not be installed underground to assist main mine fans except in anthracite mines. In anthracite mines, booster fans installed in the main air current or...

30 CFR 75.302 - Main mine fans.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ventilated by one or more main mine fans. Booster fans shall not be installed underground to assist main mine fans except in anthracite mines. In anthracite mines, booster fans installed in the main air current or...

30 CFR 75.302 - Main mine fans.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ventilated by one or more main mine fans. Booster fans shall not be installed underground to assist main mine fans except in anthracite mines. In anthracite mines, booster fans installed in the main air current or...

30 CFR 75.302 - Main mine fans.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ventilated by one or more main mine fans. Booster fans shall not be installed underground to assist main mine fans except in anthracite mines. In anthracite mines, booster fans installed in the main air current or...

30 CFR 75.302 - Main mine fans.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ventilated by one or more main mine fans. Booster fans shall not be installed underground to assist main mine fans except in anthracite mines. In anthracite mines, booster fans installed in the main air current or...

30 CFR 75.313 - Main mine fan stoppage with persons underground.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main mine fan stoppage with persons underground... mine fan stoppage with persons underground. (a) If a main mine fan stops while anyone is underground and the ventilating quantity provided by the fan is not maintained by a back-up fan system— (1...

75 FR 79952 - Airworthiness Directives; DASSAULT AVIATION Model Falcon 10 Airplanes; Model FAN JET FALCON, FAN...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-21

... Airworthiness Directives; DASSAULT AVIATION Model Falcon 10 Airplanes; Model FAN JET FALCON, FAN JET FALCON.... List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Safety. Adoption of.... (1) DASSAULT AVIATION Model Falcon 10 airplanes, Model FAN JET FALCON, FAN JET FALCON SERIES C, D, E...

Quiet High Speed Fan II (QHSF II): Final Report

NASA Technical Reports Server (NTRS)

Kontos, Karen; Weir, Don; Ross, Dave

2012-01-01

This report details the aerodynamic, mechanical, structural design and fabrication of a Honey Engines Quiet High Speed Fan II (lower hub/tip ratio and higher specific flow than the Baseline I fan). This fan/nacelle system incorporates features such as advanced forward sweep and an advanced integrated fan/fan exit guide vane design that provides for the following characteristics: (1) Reduced noise at supersonic tip speeds, in comparison to current state-of-the-art fan technology; (2) Improved aeroelastic stability within the anticipated operating envelope; and (3) Aerodynamic performance consistent with current state-of-the-art fan technology. This fan was fabricated by Honeywell and tested in the NASA Glenn 9- by 15-Ft Low Speed Wind Tunnel for aerodynamic, aeromechanical, and acoustic performance.

Cyclic Symmetry Finite Element Forced Response Analysis of a Distortion-Tolerant Fan with Boundary Layer Ingestion

NASA Technical Reports Server (NTRS)

Min, J. B.; Reddy, T. S. R.; Bakhle, M. A.; Coroneos, R. M.; Stefko, G. L.; Provenza, A. J.; Duffy, K. P.

2018-01-01

Accurate prediction of the blade vibration stress is required to determine overall durability of fan blade design under Boundary Layer Ingestion (BLI) distorted flow environments. Traditional single blade modeling technique is incapable of representing accurate modeling for the entire rotor blade system subject to complex dynamic loading behaviors and vibrations in distorted flow conditions. A particular objective of our work was to develop a high-fidelity full-rotor aeromechanics analysis capability for a system subjected to a distorted inlet flow by applying cyclic symmetry finite element modeling methodology. This reduction modeling method allows computationally very efficient analysis using a small periodic section of the full rotor blade system. Experimental testing by the use of the 8-foot by 6-foot Supersonic Wind Tunnel Test facility at NASA Glenn Research Center was also carried out for the system designated as the Boundary Layer Ingesting Inlet/Distortion-Tolerant Fan (BLI2DTF) technology development. The results obtained from the present numerical modeling technique were evaluated with those of the wind tunnel experimental test, toward establishing a computationally efficient aeromechanics analysis modeling tool facilitating for analyses of the full rotor blade systems subjected to a distorted inlet flow conditions. Fairly good correlations were achieved hence our computational modeling techniques were fully demonstrated. The analysis result showed that the safety margin requirement set in the BLI2DTF fan blade design provided a sufficient margin with respect to the operating speed range.

Corner flow control in high through-flow axial commercial fan/booster using blade 3-D optimization

NASA Astrophysics Data System (ADS)

Zhu, Fang; Jin, Donghai; Gui, Xingmin

2012-02-01

This study is aimed at using blade 3-D optimization to control corner flows in the high through-flow fan/booster of a high bypass ratio commercial turbofan engine. Two kinds of blade 3-D optimization, end-bending and bow, are focused on. On account of the respective operation mode and environment, the approach to 3-D aerodynamic modeling of rotor blades is different from stator vanes. Based on the understanding of the mechanism of the corner flow and the consideration of intensity problem for rotors, this paper uses a variety of blade 3-D optimization approaches, such as loading distribution optimization, perturbation of departure angles and stacking-axis manipulation, which are suitable for rotors and stators respectively. The obtained 3-D blades and vanes can improve the corner flow features by end-bending and bow effects. The results of this study show that flows in corners of the fan/booster, such as the fan hub region, the tip and hub of the vanes of the booster, are very complex and dominated by 3-D effects. The secondary flows there are found to have a strong detrimental effect on the compressor performance. The effects of both end-bending and bow can improve the flow separation in corners, but the specific ways they work and application scope are somewhat different. Redesigning the blades via blade 3-D optimization to control the corner flow has effectively reduced the loss generation and improved the stall margin by a large amount.

Understanding the Design, Function and Testing of Relays

ERIC Educational Resources Information Center

Adams, Roger E.; Lindbloom, Trent

2006-01-01

The increased use of electronics in today's automobiles has complicated the control of circuits and actuators. Manufacturers use relays to control a variety of complex circuits--for example, those involving actuators and other components like the A/C clutch, electronic cooling fans, and blower motors. Relays allow a switch or processor to control…

Performance on the Brink

ERIC Educational Resources Information Center

Cassidy, Michael; Medsker, Karen

2006-01-01

Bob Knight, Head Men's Basketball Coach at Texas Tech, has set a new record for the most career wins (880) in college basketball history. As Indiana University graduates (Knight coached at Indiana for 21 years), and occasional college basketball fans, the authors consider what can be learned from Bob Knight, a complex and controversial figure. The…

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.

Late Quaternary paleohydrology deduced from new marine sediment cores taken on the proximal Amazon continental margin

NASA Astrophysics Data System (ADS)

Nace, T.; Baker, P. A.; Dwyer, G. S.; Hollander, D. J.; Silva, C. G.

2010-12-01

Throughout the late Quaternary the Amazon Basin has been influenced by abrupt North-South climate forcing and has undergone several large climate variations as recorded in previously reported speleothem records. Despite its importance in the global carbon cycle there are few continuous, high-resolution records of the Amazon Basin that date back to and beyond the last glacial period. In this study, we report the first results of a marine geological expedition to the Amazon continental shelf and fan region. During this expedition we collected eight ~30 meter piston cores along with gravity, box and multicores. At both sites we undertook complementary multibeam and high resolution seismic reflection profiling. Analyses will be presented from two sets of box/gravity/piston cores. One core (32m) is from a high sedimentation site on the northern flank of the main submarine canyon within the Amazon Fan complex at 1700m water depth. The other core (30m) is located on a seamount to the south of the Amazon Fan complex at 3100m water depth. A mixed assemblage of foraminifera is used for 14C dating to obtain an age model and bulk organic geochemistry is analyzed to determine percent organic carbon, C/N ratios, δ13C and δ15N. The cores were continuously measured shipboard for magnetic susceptibility and gamma density using a GEOTEK logger. These findings uncover the contribution of pelagic and terrestrial organic matter, whether the terrigenous carbon is derived from C3 versus C4 vegetation, and whether the marine organic matter is composed of phytoplankton or marine algae.

Relative Abundance and Diversity of Bacterial Methanotrophs at the Oxic–Anoxic Interface of the Congo Deep-Sea Fan

PubMed Central

Bessette, Sandrine; Moalic, Yann; Gautey, Sébastien; Lesongeur, Françoise; Godfroy, Anne; Toffin, Laurent

2017-01-01

Sitting at ∼5,000 m water depth on the Congo-Angola margin and ∼760 km offshore of the West African coast, the recent lobe complex of the Congo deep-sea fan receives large amounts of fluvial sediments (3–5% organic carbon). This organic-rich sedimentation area harbors habitats with chemosynthetic communities similar to those of cold seeps. In this study, we investigated relative abundance, diversity and distribution of aerobic methane-oxidizing bacteria (MOB) communities at the oxic–anoxic interface of sedimentary habitats by using fluorescence in situ hybridization and comparative sequence analysis of particulate mono-oxygenase (pmoA) genes. Our findings revealed that sedimentary habitats of the recent lobe complex hosted type I and type II MOB cells and comparisons of pmoA community compositions showed variations among the different organic-rich habitats. Furthermore, the pmoA lineages were taxonomically more diverse compared to methane seep environments and were related to those found at cold seeps. Surprisingly, MOB phylogenetic lineages typical of terrestrial environments were observed at such water depth. In contrast, MOB cells or pmoA sequences were not detected at the previous lobe complex that is disconnected from the Congo River inputs. PMID:28487684

Effect on fan flow characteristics of length and axial location of a cascade thrust reverser

NASA Technical Reports Server (NTRS)

Dietrich, D. A.

1975-01-01

A series of static tests were conducted on a model fan with a diameter of 14.0 cm to determine the fan operating characteristics, the inlet static pressure contours, the fan-exit total and static pressure contours, and the fan-exit pressure distortion parameters associated with the installation of a partial-circumferential-emission cascade thrust reverser. The tests variables included the cascade axial length, the axial location of the reverser, and the type of fan inlet. It was shown that significant total and static pressure distortions were produced in the fan aft duct, and that some configurations induced a static pressure distortion at the fan face. The amount of flow passed by the fan and the level of the flow distortions were dependent upon all the variables tested.

Structural integrity of wind tunnel wooden fan blades

NASA Technical Reports Server (NTRS)

Young, Clarence P., Jr.; Wingate, Robert T.; Rooker, James R.; Mort, Kenneth W.; Zager, Harold E.

1991-01-01

Information is presented which was compiled by the NASA Inter-Center Committee on Structural Integrity of Wooden Fan Blades and is intended for use as a guide in design, fabrication, evaluation, and assurance of fan systems using wooden blades. A risk assessment approach for existing NASA wind tunnels with wooden fan blades is provided. Also, state of the art information is provided for wooden fan blade design, drive system considerations, inspection and monitoring methods, and fan blade repair. Proposed research and development activities are discussed, and recommendations are provided which are aimed at future wooden fan blade design activities and safely maintaining existing NASA wind tunnel fan blades. Information is presented that will be of value to wooden fan blade designers, fabricators, inspectors, and wind tunnel operations personnel.

Evaluation of an Outer Loop Retrofit Architecture for Intelligent Turbofan Engine Thrust Control

NASA Technical Reports Server (NTRS)

Litt, Jonathan S.; Sowers, T. Shane

2006-01-01

The thrust control capability of a retrofit architecture for intelligent turbofan engine control and diagnostics is evaluated. The focus of the study is on the portion of the hierarchical architecture that performs thrust estimation and outer loop thrust control. The inner loop controls fan speed so the outer loop automatically adjusts the engine's fan speed command to maintain thrust at the desired level, based on pilot input, even as the engine deteriorates with use. The thrust estimation accuracy is assessed under nominal and deteriorated conditions at multiple operating points, and the closed loop thrust control performance is studied, all in a complex real-time nonlinear turbofan engine simulation test bed. The estimation capability, thrust response, and robustness to uncertainty in the form of engine degradation are evaluated.

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.

Sea level controls on the textural characteristics and depositional architecture of the Hueneme and associated submarine fan systems, Santa Monica Basin, California

USGS Publications Warehouse

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

1998-01-01

Hueneme and Dume submarine fans in Santa Monica Basin consist of sandy channel and muddy levee facies on the upper fan. lenticular sand sheets on the middle fan. and thinly bedded turbidite and hemipelagic facies elsewhere. Fifteen widely correlatable key seismic reflections in high-resolution airgun and deep-towed boomer profiles subdivide the fan and basin deposits into time-slices that show different thickness and seismic-facies distributions, inferred to result from changes in Quaternary sea level and sediment supply. At times of low sea level, highly efficient turbidity currents generated by hyperpycnal flows or sediment failures at river deltas carry sand well out onto the middle-fan area. Thick, muddy flows formed rapidly prograding high levees mainly on the western (right-hand) side of three valleys that fed Hueneme fan at different times: the most recently active of the lowstand fan valleys. Hueneme fan valley, now heads in Hueneme Canyon. At times of high sea level, fans receive sand from submarine canyons that intercept littoral-drift cells and mixed sediment from earthquake-triggered slumps. Turbidity currents are confined to 'underfit' talweg channels in fan valleys and to steep, small, basin-margin fans like Dume fan. Mud is effectively separated from sand at high sea level and moves basinward across the shelf in plumes and in storm-generated lutite flows, contributing to a basin-floor blanket that is locally thicker than contemporary fan deposits and that onlaps older fans at the basin margin. The infilling of Santa Monica Basin has involved both fan and basin-floor aggradation accompanied by landward and basinward facies shifts. Progradation was restricted to the downslope growth of high muddy levees and the periodic basinward advance of the toe of the steeper and sandier Dume fan. Although the region is tectonically active, major sedimentation changes can be related to eustatic sea-level changes. The primary controls on facies shifts and fan growth appear to be an interplay of texture of source sediment, the efficiency with which turbidity currents transport sand, and the effects of delta distributary switching, all of which reflect sea-level changes.

Geochemical evidence for a complex origin for the Kelso dunes, Mojave National Preserve, California USA

USGS Publications Warehouse

Muhs, Daniel; Lancaster, Nicholas; Skipp, Gary L.

2017-01-01

The Kelso Dune field in southern California is intriguing because although it is of limited areal extent (~ 100 km2), it has a wide variety of dune forms and contains many active dunes (~ 40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source. We conducted mineralogical and geochemical studies of most of the 14 geomorphically defined dune groups of the Kelso Dune field as well as potential sand sources, alluvial sediments from the surrounding mountain ranges. Results indicate that sands in the nine western dune groups have K/Rb and K/Ba (primarily from K-feldspar) compositions that are indistinguishable from Mojave River alluvium (westerly/northwesterly winds) and Budweiser Wash alluvium (southwesterly winds), permitting an interpretation of two sources. In contrast, sands from the five eastern dune groups have K/Rb and K/Ba values that indicate significant inputs from alluvial fan deposits of the Providence Mountains. This requires either rare winds from the east or southeast or, more likely, aeolian reworking of distal Providence Mountain fan sediments by winds from the west, at a rate greater than input from the Mojave River or other western sources. The results indicate that even a small dune field can have a complex origin, either from seasonally varying winds or complex alluvial-fan-dune interaction. Application of K/Rb and K/Ba in K-feldspar as a provenance indicator could be used in many of the world's ergs or sand seas, where dune origins are still not well understood or are controversial. Four examples are given from Africa and the Middle East where such an approach could yield useful new information about dune sand provenance.

A complex origin for the Kelso Dunes, Mojave National Preserve, California, USA: A case study using a simple geochemical method with global applications

NASA Astrophysics Data System (ADS)

Muhs, Daniel R.; Lancaster, Nicholas; Skipp, Gary L.

2017-01-01

The Kelso Dune field in southern California is intriguing because although it is of limited areal extent ( 100 km2), it has a wide variety of dune forms and contains many active dunes ( 40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source. We conducted mineralogical and geochemical studies of most of the 14 geomorphically defined dune groups of the Kelso Dune field as well as potential sand sources, alluvial sediments from the surrounding mountain ranges. Results indicate that sands in the nine western dune groups have K/Rb and K/Ba (primarily from K-feldspar) compositions that are indistinguishable from Mojave River alluvium (westerly/northwesterly winds) and Budweiser Wash alluvium (southwesterly winds), permitting an interpretation of two sources. In contrast, sands from the five eastern dune groups have K/Rb and K/Ba values that indicate significant inputs from alluvial fan deposits of the Providence Mountains. This requires either rare winds from the east or southeast or, more likely, aeolian reworking of distal Providence Mountain fan sediments by winds from the west, at a rate greater than input from the Mojave River or other western sources. The results indicate that even a small dune field can have a complex origin, either from seasonally varying winds or complex alluvial-fan-dune interaction. Application of K/Rb and K/Ba in K-feldspar as a provenance indicator could be used in many of the world's ergs or sand seas, where dune origins are still not well understood or are controversial. Four examples are given from Africa and the Middle East where such an approach could yield useful new information about dune sand provenance.

Morphology and sedimentology of glacigenic submarine fans on the west Greenland continental margin

NASA Astrophysics Data System (ADS)

O'Cofaigh, Colm; Hogan, Kelly A.; Dowdeswell, Julian A.; Jennings, Anne E.; Noormets, Riko; Evans, Jeffrey

2014-05-01

Along the West Greenland continental margin adjoining Baffin Bay, bathymetric data show a series of large submarine fans located at the mouths of cross-shelf troughs. Two of these fans, the Uummannaq Fan and the Disko Fan are trough-mouth fans built largely of debris delivered from ice sheet outlets of the Greenland Ice Sheet during past glacial maxima. On the Uummannaq Fan glacigenic debris flow deposits occur on the upper slope and extend to at least 1800 m water depth in front of the trough-mouth. The debris flow deposits are related to the remobilisation of subglacial debris that was delivered onto the upper slope at times when an ice stream was positioned at the shelf edge. In contrast, sedimentary facies from the northern sector of the fan are characterised by hemipelagic and ice-rafted sediments and turbidites; glacigenic debris flows are notably absent in cores from this region. Further south along the Greenland continental margin the surface of the Disko Fan is prominently channelised and associated sediments are acoustically stratified. Although glacigenic debris flow deposits do occur on the upper Disko Fan, sediments recovered in cores from elsewhere on the fan record the influence of turbidity current and meltwater sedimentation. The channelised form of the Disko fan contrasts markedly with that of the Uummannaq Fan and, more widely, with trough mouth fans from the Polar North Atlantic. Collectively these data highlight the variability of glacimarine depositional processes operating on trough-mouth fans on high-latitude continental slopes and show that glacigenic debris flows are but one of a number of mechanisms by which such large glacially-influenced depocentres form.

Taxonomic study of the leafhopper genus Thagria Melichar (Hemiptera: Cicadellidae: Coelidiinae) from Guangxi, China.

PubMed

Fan, Zhi-Hua; Li, Zi-Zhong; Dai, Ren-Huai

2015-02-13

The paper deals with 21 valid species of the genus Thagria from Guangxi Autonomous Region, China. Eight new species are described and illustrated: T. biprocessa Fan & Dai, sp. nov., T. decussata Fan & Dai, sp. nov., T. irregularis Fan & Dai, sp. nov., T. multispinosa Fan & Dai, sp. nov., T. paramultipars Fan & Li, sp. nov., T. triangula Fan & Li, sp. nov., T. trifasciata Fan & Li, sp. nov. and T. webbi Fan & Li, sp. nov.. A key is given to distinguish all species of this genus from Guangxi, China and maps showing the geographic distribution of new species are also provided. The name Thagria xuae nom. emend. is given for T. xui Nielson.

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 based on the web-development application, SEQUEL, which includes graphics and drill-down capabilities. This paper will describe the type and amount of data taken for the fans and will give examples of this data. This paper will also describe the data-tool and gives examples of how it can be used to choose quieter fans for use in spaceflight hardware.

The Application of a Boundary Integral Equation Method to the Prediction of Ducted Fan Engine Noise

NASA Technical Reports Server (NTRS)

Dunn, M. H.; Tweed, J.; Farassat, F.

1999-01-01

The prediction of ducted fan engine noise using a boundary integral equation method (BIEM) is considered. Governing equations for the BIEM are based on linearized acoustics and describe the scattering of incident sound by a thin, finite-length cylindrical duct in the presence of a uniform axial inflow. A classical boundary value problem (BVP) is derived that includes an axisymmetric, locally reacting liner on the duct interior. Using potential theory, the BVP is recast as a system of hypersingular boundary integral equations with subsidiary conditions. We describe the integral equation derivation and solution procedure in detail. The development of the computationally efficient ducted fan noise prediction program TBIEM3D, which implements the BIEM, and its utility in conducting parametric noise reduction studies are discussed. Unlike prediction methods based on spinning mode eigenfunction expansions, the BIEM does not require the decomposition of the interior acoustic field into its radial and axial components which, for the liner case, avoids the solution of a difficult complex eigenvalue problem. Numerical spectral studies are presented to illustrate the nexus between the eigenfunction expansion representation and BIEM results. We demonstrate BIEM liner capability by examining radiation patterns for several cases of practical interest.

Settlement patterns reflected in assemblages from the Pleistocene/Holocene transition of North Central China

USGS Publications Warehouse

Madsen, D.B.; Elston, R.G.; Bettinger, R.L.; Xu, C.; Zhong, K.

1996-01-01

Survey along the margins of the Helan Mountains in the Ningxia Hui and Nei Mongol Autonomous Regions discloses variability in the distribution and assemblage composition among 47 archaeological localities, and suggests a reduction in hunter-gatherer residential mobility through time. Late Palaeolithic tool assemblages are less frequent, smaller, and relatively uniform from site to site. They tend to be found near canyon mouths on the mountain front, or around springs in the middle to upper reaches of fans, suggesting limited variation in both length of stay and subsistence strategies. In contrast, early Neolithic sites, more abundant and variable in size and complexity, are located near fan toes or lower fan springs where water could be more easily diverted. Larger more diverse assemblages suggest long-term residential bases, while smaller specialized assemblages, devoid of microliths, indicate short-term camps and resource processing locations. This helps confirm a similar pattern identified in materials collected by the Sino-Swedish expedition, in the northern Alashan. Together they suggest that the trend towards decreased residential mobility is associated with increasingly intensive and specialized use of seed resources that may be related to the early development of plant husbandry. ?? 1996 Academic Press Limited.

Sea-floor drainage features of Cascadia Basin and the adjacent continental slope, northeast Pacific Ocean

USGS Publications Warehouse

Hampton, M.A.; Karl, Herman A.; Kenyon, Neil H.

1989-01-01

Sea-floor drainage features of Cascadia Basin and the adjacent continental slope include canyons, primary fan valleys, deep-sea valleys, and remnant valley segments. Long-range sidescan sonographs and associated seismic-reflection profiles indicate that the canyons may originate along a mid-slope escarpment and grow upslope by mass wasting and downslope by valley erosion or aggradation. Most canyons are partly filled with sediment, and Quillayute Canyon is almost completely filled. Under normal growth conditions, the larger canyons connect with primary fan valleys or deep-sea valleys in Cascadia Basin, but development of accretionary ridges blocks or re-routes most canyons, forcing abandonment of the associated valleys in the basin. Astoria Fan has a primary fan valley that connects with Astoria Canyon at the fan apex. The fan valley is bordered by parallel levees on the upper fan but becomes obscure on the lower fan, where a few valley segments appear on the sonographs. Apparently, Nitinat Fan does not presently have a primary fan valley; none of the numerous valleys on the fan connect with a canyon. The Willapa-Cascadia-Vancouver-Juan de Fuca deep-sea valley system bypasses the submarine fans and includes deeply incised valleys to broad shallow swales, as well as within-valley terraces and hanging-valley confluences. ?? 1989.

Prediction of aerodynamic noise in a ring fan based on wake characteristics

NASA Astrophysics Data System (ADS)

Sasaki, Soichi; Fukuda, Masaharu; Tsujino, Masao; Tsubota, Haruhiro

2011-06-01

A ring fan is a propeller fan that applies an axial-flow impeller with a ring-shaped shroud on the blade tip side. In this study, the entire flow field of the ring fan is simulated using computational fluid dynamics (CFD); the accuracy of the CFD is verified through a comparison with the aerodynamic characteristics of a propeller fan of current model. Moreover, the aerodynamic noise generated by the fan is predicted on the basis of the wake characteristics. The aerodynamic characteristic of the ring fan based on CFD can represent qualitatively the variation in the measured value. The main flow domain of the ring fan is formed at the tip side of the blade because blade tip vortex is not formed at that location. Therefore, the relative velocity of the ring fan is increased by the circumferential velocity. The sound pressure levels of the ring fan within the frequency band of less than 200 Hz are larger than that of the propeller fan. In the analysis of the wake characteristics, it revealed that Karman vortex shedding occurred in the main flow domain in the frequency domain lower than 200 Hz; the aerodynamic noise of the ring fan in the vortex shedding frequency enlarges due to increase in the relative velocity and the velocity fluctuation.

Transcriptional organization of the DNA region controlling expression of the K99 gene cluster.

PubMed

Roosendaal, B; Damoiseaux, J; Jordi, W; de Graaf, F K

1989-01-01

The transcriptional organization of the K99 gene cluster was investigated in two ways. First, the DNA region, containing the transcriptional signals was analyzed using a transcription vector system with Escherichia coli galactokinase (GalK) as assayable marker and second, an in vitro transcription system was employed. A detailed analysis of the transcription signals revealed that a strong promoter PA and a moderate promoter PB are located upstream of fanA and fanB, respectively. No promoter activity was detected in the intercistronic region between fanB and fanC. Factor-dependent terminators of transcription were detected and are probably located in the intercistronic region between fanA and fanB (T1), and between fanB and fanC (T2). A third terminator (T3) was observed between fanC and fanD and has an efficiency of 90%. Analysis of the regulatory region in an in vitro transcription system confirmed the location of the respective transcription signals. A model for the transcriptional organization of the K99 cluster is presented. Indications were obtained that the trans-acting regulatory polypeptides FanA and FanB both function as anti-terminators. A model for the regulation of expression of the K99 gene cluster is postulated.

14 CFR 29.908 - Cooling fans.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Cooling fans. 29.908 Section 29.908... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant General § 29.908 Cooling fans. For cooling fans that are a part of a powerplant installation the following apply: (a) Category A. For cooling fans installed...

30 CFR 57.8519 - Underground main fan controls.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground main fan controls. 57.8519 Section... Ventilation Surface and Underground § 57.8519 Underground main fan controls. All underground main fans shall have controls placed at a suitable protected location remote from the fan and preferably on the surface...

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— (1...

30 CFR 57.22205 - Doors on main fans (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Doors on main fans (I-A, II-A, III, and V-A... main fans (I-A, II-A, III, and V-A mines). In mines ventilated by multiple main fans, each main fan... reversal through the fan. The doors shall be located so that they are not in direct line with explosive...

Design Guidelines for Quiet Fans and Pumps for Space Vehicles

NASA Technical Reports Server (NTRS)

Lovell, John S.; Magliozzi, Bernard

2008-01-01

This document presents guidelines for the design of quiet fans and pumps of the class used on space vehicles. A simple procedure is presented for the prediction of fan noise over the meaningful frequency spectrum. A section also presents general design criteria for axial flow fans, squirrel cage fans, centrifugal fans, and centrifugal pumps. The basis for this report is an experimental program conducted by Hamilton Standard under NASA Contract NAS 9-12457. The derivations of the noise predicting methods used in this document are explained in Hamilton Standard Report SVHSER 6183, "Fan and Pump Noise Control," dated May 1973 (6).

Tune-Up Your Fan Systems for Improved Performance

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

Fans are used extensively in commercial buildings and represent approximately 6% of total energy consumed by commercial buildings. The U.S. Department of Energy (DOE) estimates that fans in commercial buildings consume 158 billion kWh of electricity annually. Maintaining fan systems in proper condition provides energy savings and ensures a comfortable and healthy environment. While many fan systems have significant energy savings opportunities available through improvements in fan selection, system design, and operational practices, it is not always apparent when a fan system needs maintenance or what opportunities are available for improvements. This resource is designed for facility managers and maintenancemore » staff to provide easy-to-implement actionable guidance on fan efficiency measures for existing ducted air systems.« less

Development Specification for the FN-323/324, Oxygen Ventilation Loop Fan Assembly

NASA Technical Reports Server (NTRS)

Ralston, Russell; Campbell, Colin

2017-01-01

This specification establishes the requirements for design, performance, safety, and manufacture of the FN-323/324, Oxygen Ventilation Loop Fan Assembly as part of the Advanced EMU (AEMU) Portable Life Support System (PLSS). Fan development for the advanced Portable Life Support System (PLSS) began in 2009 with the development of Fan 1.0. This fan was used in PLSS 2.0 for circulation of the ventilation loop gas. Fan 2.0 was delivered in 2015 and will be used in the PLSS 2.5 Live Loads test series. This fan used the same motor as Fan 1.0, but had a larger volute and impeller in hopes of achieving lower speeds. The next iteration of the advanced PLSS fan is the subject of the requirements contained within this document, and will be used with the PLSS 2.5 -302 configuration.

Design study and performance analysis of a high-speed multistage variable-geometry fan for a variable cycle engine

NASA Technical Reports Server (NTRS)

Sullivan, T. J.; Parker, D. E.

1979-01-01

A design technology study was performed to identify a high speed, multistage, variable geometry fan configuration capable of achieving wide flow modulation with near optimum efficiency at the important operating condition. A parametric screening study of the front and rear block fans was conducted in which the influence of major fan design features on weight and efficiency was determined. Key design parameters were varied systematically to determine the fan configuration most suited for a double bypass, variable cycle engine. Two and three stage fans were considered for the front block. A single stage, core driven fan was studied for the rear block. Variable geometry concepts were evaluated to provide near optimum off design performance. A detailed aerodynamic design and a preliminary mechanical design were carried out for the selected fan configuration. Performance predictions were made for the front and rear block fans.

Effect of crossflow velocity on VTOL lift fan blade passing frequency noise generation

NASA Technical Reports Server (NTRS)

Stimpert, D. L.

1973-01-01

Analysis of noise measurements taken during tests of a remote lift fan wing installation, a V/STOL model transport with both lift and lift/cruise fans, and XV5B research aircraft flight tests has indicated a definite increase in pure tone sound pressure level due to crossflow over the face of the life fans. The fan-in-wing and V/STOL model transport tests were conducted in the NASA Ames 40 ft. by 80 ft. wing tunnel and the XV5B flight tests at Moffett Field. Increases up to 10 db were observed for the lift fan installation tested at crossflow to fan tip velocity ratios up to 0.25. Cruise fan noise levels were found to be unaffected by the external flow. The noise level increase was shown to be related to an increase in fan distortion levels.

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.

Experimental investigation of the noise emission of axial fans under distorted inflow conditions

NASA Astrophysics Data System (ADS)

Zenger, Florian J.; Renz, Andreas; Becher, Marcus; Becker, Stefan

2016-11-01

An experimental investigation on the noise emission of axial fans under distorted inflow conditions was conducted. Three fans with forward-skewed fan blades and three fans with backward-skewed fan blades and a common operating point were designed with a 2D element blade method. Two approaches were adopted to modify the inflow conditions: first, the inflow turbulence intensity was increased by two different rectangular grids and second, the inflow velocity profile was changed to an asymmetric characteristic by two grids with a distinct bar stacking. An increase in the inflow turbulence intensity affects both tonal and broadband noise, whereas a non-uniform velocity profile at the inlet influences mainly tonal components. The magnitude of this effect is not the same for all fans but is dependent on the blade skew. The impact is greater for the forward-skewed fans than for the backward-skewed and thus directly linked to the fan blade geometry.

Health assessment of cooling fan bearings using wavelet-based filtering.

PubMed

Miao, Qiang; Tang, Chao; Liang, Wei; Pecht, Michael

2012-12-24

As commonly used forced convection air cooling devices in electronics, cooling fans are crucial for guaranteeing the reliability of electronic systems. In a cooling fan assembly, fan bearing failure is a major failure mode that causes excessive vibration, noise, reduction in rotation speed, locked rotor, failure to start, and other problems; therefore, it is necessary to conduct research on the health assessment of cooling fan bearings. This paper presents a vibration-based fan bearing health evaluation method using comblet filtering and exponentially weighted moving average. A new health condition indicator (HCI) for fan bearing degradation assessment is proposed. In order to collect the vibration data for validation of the proposed method, a cooling fan accelerated life test was conducted to simulate the lubricant starvation of fan bearings. A comparison between the proposed method and methods in previous studies (i.e., root mean square, kurtosis, and fault growth parameter) was carried out to assess the performance of the HCI. The analysis results suggest that the HCI can identify incipient fan bearing failures and describe the bearing degradation process. Overall, the work presented in this paper provides a promising method for fan bearing health evaluation and prognosis.

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.

Health Assessment of Cooling Fan Bearings Using Wavelet-Based Filtering

PubMed Central

Miao, Qiang; Tang, Chao; Liang, Wei; Pecht, Michael

2013-01-01

As commonly used forced convection air cooling devices in electronics, cooling fans are crucial for guaranteeing the reliability of electronic systems. In a cooling fan assembly, fan bearing failure is a major failure mode that causes excessive vibration, noise, reduction in rotation speed, locked rotor, failure to start, and other problems; therefore, it is necessary to conduct research on the health assessment of cooling fan bearings. This paper presents a vibration-based fan bearing health evaluation method using comblet filtering and exponentially weighted moving average. A new health condition indicator (HCI) for fan bearing degradation assessment is proposed. In order to collect the vibration data for validation of the proposed method, a cooling fan accelerated life test was conducted to simulate the lubricant starvation of fan bearings. A comparison between the proposed method and methods in previous studies (i.e., root mean square, kurtosis, and fault growth parameter) was carried out to assess the performance of the HCI. The analysis results suggest that the HCI can identify incipient fan bearing failures and describe the bearing degradation process. Overall, the work presented in this paper provides a promising method for fan bearing health evaluation and prognosis. PMID:23262486

An Aquifer Thermal Energy Storage (ATES) System for Continuous and Sustainable Cold Supply in Oman

NASA Astrophysics Data System (ADS)

Winterleitner, G.; Schütz, F.; Huenges, E.

2016-12-01

The aim of the GeoSolCool research programme between the German Research Centre for Geoscience (GFZ) and The Research Council of Oman (TRC) is the development of an innovative and sustainable cooling system in combination with an aquifer thermal energy storage system in northern Oman. An integral part of this project is the design of a subsurface aquifer reservoir system for storage of thermal energy through hot water injection. An accurate characterisation of potential storage horizons is thus essential to ensure optimal efficiency of the cooling system. The study area, 40 km west of Muscat is characterised by a thick Cenozoic mixed carbonate-siliciclastic sedimentary succession, containing at least 3 aquifer horizons. We used a multidisciplinary approach for the initial ATES development phase, including geological fieldwork dovetailed with remote sensing analyses, thin-section analyses, geological modelling and reservoir fluid flow forecasting. First results indicate two potential storage horizons: (1) a Miocene-aged clastic-dominated alluvial fan system and (2) an Eocene carbonate sequence. The alluvial fan system is a more than 300 m thick, coarse clastic (mainly gravels and sandstones) succession of coalesced individual fans. Thin-section analyses showed that hydraulic parameters are favourable for the gravel and sandstone intervals but reservoir architecture is complex due to multiple generations of interconnecting fans with highly heterogeneous facies distributions. The Eocene carbonates were deposited in a carbonate ramp setting, strongly influenced by currents and storm events. Individual facies belts extend over kilometres and thus horizontal reservoir connectivity is expected to be good with minor facies variability. Thin-section analyses showed that especially the fossil-rich sections show good storage qualities. Fluid flow forecasting indicate that both potential horizons have good to very good storage characteristics. However, intense diagenetic overprint of the succession and a complex reservoir architecture of the Miocene clastics might pose challenges for the ATES implementation. In order to decide which storage horizon will be developed as an ATES system, drilling of an exploration well and subsequent well-logging and hydraulic testing is underway.

Groundwater-surface water interactions in a glacierized catchment and their influence on proglacial water supply

NASA Astrophysics Data System (ADS)

Gordon, R. P.; Lautz, L. K.; McKenzie, J. M.; Mark, B. G.

2012-12-01

The tropical glaciers of the Cordillera Blanca of Peru are retreating rapidly due to climate change, which threatens water resources for the quarter-million inhabitants of the upper Rio Santa river valley and many more downstream. Recent studies have shown that glacial melt supplies approximately half of dry season stream discharge in Cordillera Blanca valleys. The remainder of streamflow is supplied by groundwater stored in alpine meadows, moraines and talus slopes. In the future, when glacier loss has reduced the influence of melt water on streams, groundwater discharge will be the primary dry-season source of stream water for irrigation, municipalities, and hydropower in the Santa watershed. A better understanding of the dynamics of alpine groundwater, including sources and exchange fluxes, is therefore important for future planning in this region. Understanding these groundwater-surface water interactions is necessary for making accurate estimates of meltwater contributions to the hydrologic budget, and for our ability to make predictions about future water resources under deglaciating conditions. We combined measurements of groundwater-surface water exchange during the dry season with synoptic sampling of stream water and end-members in order to quantify the groundwater contributions to streamflow from an alpine meadow, debris fan, and moraine complex in a glacierized valley of the Cordillera Blanca. Using stream tracer-dilution techniques, we calculated channel water balances for 9 stream reaches of 100-200 m throughout the meadow and measured the discharge of glacial meltwater into debris fan and moraine units. We used vertical heat tracing to measure stream-groundwater exchange at 2-hour increments over 2 weeks in 13 stream locations in the meadow, debris fan, and moraine units. Channel water balance and heat tracing results show that, during the studied portion of the dry season, the stream loses water (2.5 l/s or ~25% of flow) to the subsurface in the upstream half of the meadow, and gains water (7 l/s or ~6% of flow) in the lower half. The debris fan adjacent to the meadow received 22 l/s of surficial melt water from a glacial lake but contributed ~100 l/s of streamflow to the meadow, mostly through springs at the fan-meadow interface. In contrast, the terminal moraine complex at the head of the meadow received 36 l/s of glacial lake discharge but only contributed 5 l/s of streamflow to the meadow; the remainder of stream discharge over the moraine was apparently lost to an underlying aquifer. Results show that gains and losses of stream water are unequally distributed across the landscape in the dry season, with the debris fan and meadow being net sources of streamflow, and the moraine a net sink. Almost all of the stream water exiting the catchment (115 l/s) spent some time in the subsurface, with approximately half originating as groundwater within the studied watershed.

Computational Aerodynamic Simulations of a 1215 ft/sec Tip Speed Transonic Fan System Model for Acoustic Methods Assessment and Development

NASA Technical Reports Server (NTRS)

Tweedt, Daniel L.

2014-01-01

Computational Aerodynamic simulations of a 1215 ft/sec tip speed transonic fan system were performed at five different operating points on the fan operating line, in order to provide detailed internal flow field information for use with fan acoustic prediction methods presently being developed, assessed and validated. The fan system is a sub-scale, low-noise research fan/nacelle model that has undergone extensive experimental testing in the 9- by 15-foot Low Speed Wind Tunnel at the NASA Glenn Research Center. Details of the fan geometry, the computational fluid dynamics methods, the computational grids, and various computational parameters relevant to the numerical simulations are discussed. Flow field results for three of the five operating points simulated are presented in order to provide a representative look at the computed solutions. Each of the five fan aerodynamic simulations involved the entire fan system, which for this model did not include a split flow path with core and bypass ducts. As a result, it was only necessary to adjust fan rotational speed in order to set the fan operating point, leading to operating points that lie on a fan operating line and making mass flow rate a fully dependent parameter. The resulting mass flow rates are in good agreement with measurement values. Computed blade row flow fields at all fan operating points are, in general, aerodynamically healthy. Rotor blade and fan exit guide vane flow characteristics are good, including incidence and deviation angles, chordwise static pressure distributions, blade surface boundary layers, secondary flow structures, and blade wakes. Examination of the flow fields at all operating conditions reveals no excessive boundary layer separations or related secondary-flow problems.

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

USDA-ARS?s Scientific Manuscript database

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...

The Crisis Posting: Scenarios for Class Discussion and Creation

ERIC Educational Resources Information Center

Jebb, John F.

2005-01-01

For years, the author has been a fan of assigning students in business communication classes to draft messages that explained complex decisions or situations. The assignment is the author's variation of the negative or bad news message. This traditional genre has generated a new Web-based method by which people and organizations respond to public…

Conceptual design studies of lift/cruise fans for military transports

NASA Technical Reports Server (NTRS)

1974-01-01

A study program for conceptual design studies of remote lift and lift/cruise fan systems to meet the requirements of military V/STOL aircraft was conducted. Parametric performance and design data are presented for fans covering a range of pressure ratios, including both single and two stage fan concepts. The gas generator selected for these fan systems was the J101-GE-100 engine. Noise generation and transient response were determined for selected fan systems.

3D architecture of cyclic-step and antidune deposits in glacigenic subaqueous fan and delta settings: Integrating outcrop and ground-penetrating radar data

NASA Astrophysics Data System (ADS)

Lang, Jörg; Sievers, Julian; Loewer, Markus; Igel, Jan; Winsemann, Jutta

2017-12-01

Bedforms related to supercritical flows are increasingly recognised as important constituents of many depositional environments, but outcrop studies are commonly hampered by long bedform wavelengths and complex three-dimensional geometries. We combined outcrop-based facies analysis with ground-penetrating radar (GPR) surveys to analyse the 3D facies architecture of subaqueous ice-contact fan and glacifluvial delta deposits. The studied sedimentary systems were deposited at the margins of the Middle Pleistocene Scandinavian ice sheets in Northern Germany. Glacifluvial Gilbert-type deltas are characterised by steeply dipping foreset beds, comprising cyclic-step deposits, which alternate with antidune deposits. Deposits of cyclic steps consist of lenticular scours infilled by backset cross-stratified pebbly sand and gravel. The GPR sections show that the scour fills form trains along the delta foresets, which can locally be traced for up to 15 m. Perpendicular and oblique to palaeoflow direction, these deposits appear as troughs with concentric or low-angle cross-stratified infills. Downflow transitions from scour fills into sheet-like low-angle cross-stratified or sinusoidally stratified pebbly sand, deposited by antidunes, are common. Cyclic steps and antidunes were deposited by sustained and surge-type supercritical density flows, which were related to hyperpycnal flows, triggered by major meltwater discharge or slope-failure events. Subaqueous ice-contact fan deposits include deposits of progradational scour fills, isolated hydraulic jumps, antidunes and (humpback) dunes. The gravel-rich fan succession consists of vertical stacks of laterally amalgamated pseudo-sheets, indicating deposition by pulses of waning supercritical flows under high aggradation rates. The GPR sections reveal the large-scale architecture of the sand-rich fan succession, which is characterised by lobe elements with basal erosional surfaces associated with scours filled with backsets related to hydraulic jumps, passing upwards and downflow into deposits of antidunes and (humpback) dunes. The recurrent facies architecture of the lobe elements and their prograding and retrograding stacking pattern are interpreted as related to autogenic flow morphodynamics.

Quantifying relief on alluvial fans using airborne lidar to reveal patterns of sediment accumulation

NASA Astrophysics Data System (ADS)

Morelan, A. E., III; Oskin, M. E.

2017-12-01

We present a method of quantifying detailed surface relief on alluvial fans from high-resolution topography. Average slope and curvature of the fan are used together to empirically derive an idealized, radially symmetric fan surface, from which we compute residual topography. Maps produced using this technique highlight spatial patterns of fan deposition and avulsion. Regions of high residual topography reveal active and abandoned sediment lobes accumulated from recent depositional events, often with well-defined channels at their apex. Preliminary observations suggest that surface relief is uniform across a collection of fans in a given region and source lithology. Alluvial fans with granitic catchment lithologies in eastern California (n=12), each with varying source catchment size and mean fan slope, all show relief of around 4 meters. A collection of fans from the Carrizo Plain in central California (n=12), with source catchments set within Miocene marine and nonmarine sedimentary rocks, show significantly lower relief values around 2 meters. We hypothesize that particle grain size determines this contrasting relief through its control on the thickness of fan-building debris flows. In both settings we find that sediment lobes tend to extend toward the fan toe. This pattern supports a process, observed in analog experiments, of fan deposition dominated by back-filling and overtopping of distributary channels by debris-flows.

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.

78 FR 25626 - Energy Conservation Program for Consumer Products: Energy Conservation Standards for Ceiling Fans...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-02

... Light Kits AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION... for residential ceiling fans and ceiling fan light kits in the Federal Register. This document... other aspect of the rulemaking for ceiling fans and ceiling fan light kits. The comment period is...

30 CFR 77.212 - Draw-off tunnel ventilation fans; installation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Draw-off tunnel ventilation fans; installation... UNDERGROUND COAL MINES Surface Installations § 77.212 Draw-off tunnel ventilation fans; installation. When fans are used to ventilate draw-off tunnels the fans shall be: (a) Installed on the surface; (b...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2014 CFR

2014-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2012 CFR

2012-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2010 CFR

2010-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2011 CFR

2011-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2013 CFR

2013-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

Online Fan Practices and CALL

ERIC Educational Resources Information Center

Sauro, Shannon

2017-01-01

This article provides a narrative overview of research on online fan practices for language and literacy learning, use, and identity work. I begin with an introduction to online fan communities and common fan practices found in these online affinity spaces, the best known of which is fan fiction, fictional writing that reinterprets and remixes the…

Counterrotatable booster compressor assembly for a gas turbine engine

NASA Technical Reports Server (NTRS)

Moniz, Thomas Ory (Inventor); Orlando, Robert Joseph (Inventor)

2004-01-01

A counterrotatable booster compressor assembly for a gas turbine engine having a counterrotatable fan section with a first fan blade row connected to a first drive shaft and a second fan blade row axially spaced from the first fan blade row and connected to a second drive shaft, the counterrotatable booster compressor assembly including a first compressor blade row connected to the first drive shaft and a second compressor blade row interdigitated with the first compressor blade row and connected to the second drive shaft. A portion of each fan blade of the second fan blade row extends through a flowpath of the counterrotatable booster compressor so as to function as a compressor blade in the second compressor blade row. The counterrotatable booster compressor further includes a first platform member integral with each fan blade of the second fan blade row at a first location so as to form an inner flowpath for the counterrotatable booster compressor and a second platform member integral with each fan blade of the second fan blade row at a second location so as to form an outer flowpath for the counterrotatable booster compressor.

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

Authors Tracey Smith^1, Rob Jacob^1, Jeffrey Trop^1, Keith Williams^2 and Craig Kochel^1 Bucknell University, Geology and Environmental Geoscience Department, Lewisburg, PA UNAVCO, 6350 Nautilus Dr., Boulder, CO 80301 Icy debris fans have recently been described as deglaciation features on Earth and similar features have been observed on Mars, however, the subsurface characteristics remain unknown. We used ground penetrating radar (GPR) to non-invasively investigate the subsurface characteristics of icy debris fans near McCarthy, Alaska, USA. The three fans investigated in Alaska are the East, West, and Middle fans which are between the Nabesna ice cap and the McCarthy Glacier. Icy debris fans in general are a largely unexplored suite of paraglacial landforms and processes in alpine regions. Recent field studies focused on direct observations and depositional processes. The results showed that each fan's composition is primarily influenced by the type and frequency of mass wasting processes that supply the fan. Photographic studies show that the East fan receives far more ice and snow avalanches whereas the Middle and West fan receive fewer mass wasting events but more clastic debris is deposited on the Middle and West fan from rock falls and icy debris flows. GPR profiles and WARR surveys consisting of both, common mid-point (CMP), and common shot-point (CSP) surveys investigated the subsurface geometry of the fans and the McCarthy Glacier.All GPR surveys were collected in 2013 with 100MHz bi-static antennas. Four axial profiles and three cross-fan profiles were done on the West and Middle fans as well as the McCarthy Glacier in order to investigate the relationship between the three features. Terrestrial laser surveying of the surface and real-time kinematic GPS provided the surface elevation used to correct the GPR data for topographic changes. GPR profiles yielded reflectors that were continuous for 10+ m and hyperbolic reflections in the subsurface. The WARR 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.

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.

Nocturnal Fanning Suppresses Downy Mildew Epidemics in Sweet Basil

PubMed Central

Cohen, Yigal; Ben-Naim, Yariv

2016-01-01

Downy mildew is currently the most serious disease of sweet basil around the world. The oomycete causal agent Peronospora belbahrii requires ≥ 4h free leaf moisture for infection and ≥7.5h of water-saturated atmosphere (relative humidity RH≥95%) at night for sporulation. We show here that continued nocturnal fanning (wind speed of 0.4–1.5 m/s) from 8pm to 8am dramatically suppressed downy mildew development. In three experiments conducted during 2015, percent infected leaves in regular (non-fanned) net-houses reached a mean of 89.9, 94.3 and 96.0% compared to1.2, 1.7 and 0.5% in adjacent fanned net-houses, respectively. Nocturnal fanning reduced the number of hours per night with RH≥95% thus shortened the dew periods below the threshold required for infection or sporulation. In experiments A, B and C, the number of nights with ≥4h of RH≥95% was 28, 10 and 17 in the non-fanned net-houses compared to 5, 0 and 5 in the fanned net-houses, respectively. In the third experiment leaf wetness sensors were installed. Dew formation was strongly suppressed in the fanned net-house as compared to the non-fanned net-house. Healthy potted plants became infected and sporulated a week later if placed one night in the non-fanned house whereas healthy plants placed during that night in the fanned house remained healthy. Infected potted basil plants sporulated heavily after one night of incubation in the non-fanned house whereas almost no sporulation occurred in similar plants incubated that night in the fanned house. The data suggest that nocturnal fanning is highly effective in suppressing downy mildew epidemics in sweet basil. Fanning prevented the within-canopy RH from reaching saturation, reduced dew deposition on the leaves, and hence prevented both infection and sporulation of P. belbahrii. PMID:27171554

Static test of a fan-powered chin nozzle for V/STOl applications

NASA Technical Reports Server (NTRS)

Salemann, V.

1981-01-01

The performance of a "chin" nozzle which diverts flow in a downward direction immediately downstream of a fan typical of designs suitable for V/STOL A applications was evaluated. Back pressure distortion to the fan and fan discharge pressure distortion were also measured. Results show that the distortion is significant at the closest spacing between the fan exit and cascade entrance tested, and that the chin nozzle performance deteriorates with increased flow diversion to the chin nozzle. Color oil flow visualization on video tape and still photos were also obtained. Tests were conducted behind a 12" model fan in the NASA-Lewis fan calibration facility.

Risk identification and prediction of coal workers' pneumoconiosis in Kailuan Colliery Group in China: a historical cohort study.

PubMed

Shen, Fuhai; Yuan, Juxiang; Sun, Zhiqian; Hua, Zhengbing; Qin, Tianbang; Yao, Sanqiao; Fan, Xueyun; Chen, Weihong; Liu, Hongbo; Chen, Jie

2013-01-01

Prior to 1970, coal mining technology and prevention measures in China were poor. Mechanized coal mining equipment and advanced protection measures were continuously installed in the mines after 1970. All these improvements may have resulted in a change in the incidence of coal workers' pneumoconiosis (CWP). Therefore, it is important to identify the characteristics of CWP today and trends for the incidence of CWP in the future. A total of 17,023 coal workers from the Kailuan Colliery Group were studied. A life-table method was used to calculate the cumulative incidence rate of CWP and predict the number of new CWP patients in the future. The probability of developing CWP was estimated by a multilayer perceptron artificial neural network for each coal worker without CWP. The results showed that the cumulative incidence rates of CWP for tunneling, mining, combining, and helping workers were 31.8%, 27.5%, 24.2%, and 2.6%, respectively, during the same observation period of 40 years. It was estimated that there would be 844 new CWP cases among 16,185 coal workers without CWP within their life expectancy. There would be 273.1, 273.1, 227.6, and 69.9 new CWP patients in the next <10, 10-, 20-, and 30- years respectively in the study cohort within their life expectancy. It was identified that coal workers whose risk probabilities were over 0.2 were at high risk for CWP, and whose risk probabilities were under 0.1 were at low risk. The present and future incidence trends of CWP remain high among coal workers. We suggest that coal workers at high risk of CWP undergo a physical examination for pneumoconiosis every year, and the coal workers at low risk of CWP be examined every 5 years.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quiet, Efficient Fans for Spaceflight: An Overview of NASA's Technology Development Plan

NASA Technical Reports Server (NTRS)

Koch, L. Danielle

2010-01-01

A Technology Development Plan to improve the aerodynamic and acoustic performance of spaceflight fans has been submitted to NASA s Exploration Technology Development Program. The plan describes a research program intended to make broader use of the technology developed at NASA Glenn to increase the efficiency and reduce the noise of aircraft engine fans. The goal is to develop a set of well-characterized government-owned fans nominally suited for spacecraft ventilation and cooling systems. NASA s Exploration Life Support community will identify design point conditions for the fans in this study. Computational Fluid Dynamics codes will be used in the design and analysis process. The fans will be built and used in a series of tests. Data from aerodynamic and acoustic performance tests will be used to validate performance predictions. These performance maps will also be entered into a database to help spaceflight fan system developers make informed design choices. Velocity measurements downstream of fan rotor blades and stator vanes will also be collected and used for code validation. Details of the fan design, analysis, and testing will be publicly reported. With access to fan geometry and test data, the small fan industry can independently evaluate design and analysis methods and work towards improvement.

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.

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.

Summary of Lift and Lift/Cruise Fan Powered Lift Concept Technology

NASA Technical Reports Server (NTRS)

Cook, Woodrow L.

1993-01-01

A summary is presented of some of the lift and lift/cruise fan technology including fan performance, fan stall, ground effects, ingestion and thrust loss, design tradeoffs and integration, control effectiveness and several other areas related to vertical short takeoff and landing (V/STOL) aircraft conceptual design. The various subjects addressed, while not necessarily pertinent to specific short takeoff/vertical landing (STOVL) supersonic designs being considered, are of interest to the general field of lift and lift/cruise fan aircraft designs and may be of importance in the future. The various wind tunnel and static tests reviewed are: (1) the Doak VZ-4 ducted fan, (2) the 0.57 scale model of the Bell X-22 ducted fan aircraft, (3) the Avrocar, (4) the General Electric lift/cruise fan, (5) the vertical short takeoff and landing (V/STOL) lift engine configurations related to ingestion and consequent thrust loss, (6) the XV-5 and other fan-in-wing stall consideration, (7) hybrid configurations such as lift fan and lift/cruise fan or engines, and (8) the various conceptual design studies by air-frame contractors. Other design integration problems related to small and large V/STOL transport aircraft are summarized including lessons learned during more recent conceptual design studies related to a small executive V/STOL transport aircraft.

Placer lag deposits in submarine channels in the Gulf of Alaska

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

Dobson, M.R.; Huggett, Q.

1990-06-01

GLORIA surveys in the Gulf of Alaska during 1989 have revealed details of sediment transport systems that cross the Slope, Rise, and adjacent abyssal plain. Two systems dominate: channel-levee complexes that promote the construction of major fans, and large single channels with subdued overbank activities which terminate as extended sediment lobes that may coalesce to give sand plains. Both channel types originate from Upper Slope gulley zones developed on rapidly dumped shelf edge fans associated with major tidewater glaciers that during periods of climatic deterioration and lower sea levels extended across the narrow shelf to the top of the Slope.more » Thus, the sediment source for these channel systems consists of unsorted rapidly abandoned glacial debris. The nature of initial emplacement of unsorted sediments is significant because the Alaskan provenance area is rich in heavy or placer type minerals; particularly those with economic value such as gold and platinum. The reworking of these sediments along submarine channels that morphologically have strong similarities with subaerial systems makes placer prospecting a viable proposition. Surveys using GLORIA, 10 KHz, and 3.5 KHz profilers together with a 140 in.{sup 3} airgun array have allowed the identification of prospecting sites and provided the control for the development of predictive models for those processes that ensure heavy mineral concentration in the transport regimes identified for this margin. Importantly, because this margin is an active transform type, individual fans, sourcing as they do from restricted sites along this coastline, are short-lived such that even abandoned fans offer prospects for the surveyor.« less

Submarine canyon and fan systems of the California Continental Borderland

USGS Publications Warehouse

Normark, W.R.; Piper, D.J.W.; Romans, B.W.; Covault, J.A.; Dartnell, P.; Sliter, R.W.

2009-01-01

Late Quaternary turbidite and related gravity-flow deposits have accumulated in basins of the California Borderland under a variety of conditions of sediment supply and sea-level stand. The northern basins (Santa Barbara, Santa Monica, and San Pedro) are closed and thus trap virtually all sediment supplied through submarine canyons and smaller gulley systems along the basin margins. The southern basins (Gulf of Santa Catalina and San Diego Trough) are open, and, under some conditions, turbidity currents flow from one basin to another. Seismic-reflection profiles at a variety of resolutions are used to determine the distribution of late Quaternary turbidites. Patterns of turbidite-dominated deposition during lowstand conditions of oxygen isotope stages 2 and 6 are similar within each of the basins. Chronology is provided by radiocarbon dating of sediment from two Ocean Drilling Program sites, the Mohole test-drill site, and large numbers of piston cores. High-resolution, seismic-stratigraphic frameworks developed for Santa Monica Basin and the open southern basins show rapid lateral shifts in sediment accumulation on scales that range from individual lobe elements to entire fan complexes. More than half of the submarine fans in the Borderland remain active at any given position of relative sea level. Where the continental shelf is narrow, canyons are able to cut headward during sea-level transgression and maintain sediment supply to the basins from rivers and longshore currents during highstands. Rivers with high bedload discharge transfer sediment to submarine fans during both highstand and lowstand conditions. ?? 2009 The Geological Society of America.

High-speed, bi-directional dual-core fiber transmission system for high-density, short-reach optical interconnects

NASA Astrophysics Data System (ADS)

Geng, Ying; Li, Shenping; Li, Ming-Jun; Sutton, Clifford G.; McCollum, Robert L.; McClure, Randy L.; Koklyushkin, Alexander V.; Matthews, Karen I.; Luther, James P.; Butler, Douglas L.

2015-03-01

A complete single mode dual-core fiber system for short-reach optical interconnects is fabricated and tested for high-speed data transmission. It includes dual-core fibers capable of bi-directional data transmission, dual-core simplex LC connectors, and fan-outs. The transmission system offers simplified bi-directional traffic engineering with integrated bidirectional transceivers and compact system design, utilizing simplex dual-core LC connectors that use half the space while increasing the bandwidth density by a factor of two. The fiber has two cores that are compatible with single mode fiber and conforms to the industry standard outer diameter of 125 μm. This reduces operational complexity by reducing the size and number of fibers, cables and connectors. Measured OTDR loss for both cores was 0.34 dB/km at 1310 nm and 0.19 dB/km at 1550 nm. Crosstalk for a piece of 5.8 km long dual-core fiber was measured to be below -75 dB at 1310 nm, and below -40 dB at 1550 nm. Both free-space optics fan-outs and tapered-fiber-coupler based MCF fan-outs were evaluated for the transmission system. Error-free and penalty-free 25 Gb/s bi-directional transmission performance was demonstrated for three different fiber lengths, 200 m, 2 km and 10 km, using the complete all-fiber-based system including connectors and fan-outs. This single mode, dual-core fiber transmission system adds complementary value to systems where additional increases in bandwidth density can come from wavelength division multiplexing and multiple bits per symbol.

One-Dimensional Hydraulic Theory Applied to Experimental Subaqueous Fans with Supercritical Distributaries

NASA Astrophysics Data System (ADS)

Hamilton, P.; Strom, K.; Hoyal, D. C. J. D.

2015-12-01

Subaqueous fans are distributive channel systems that form in a variety of settings including offshore marine, sub-lacustrine, and reservoirs. These distributive systems create complex sedimentation patterns through repeated avulsion to fill in a basin. Here we ran a series of experiments to explore the intrinsic controls on avulsion cycles on subaqueous fans. Experiments are a convenient way to study these systems since the time-scale of fan development is dramatically shortened compared to natural settings, all boundary conditions can be controlled, and the experimental domain can be instrumented to monitor the pertinent hydraulic and morphologic variables. Experiments in this study used saline underflows and crushed plastic sediment fed down an imposed slope covered in the sediment. Avulsion cycles are a central feature in these experiments which are characterized by: (1) channel extension and stagnation; (2) bar aggradation and hydraulic jump initiation; (3) upstream retreat; and (4) flow avulsion. Looking at and analyzing these cycles yield the following conclusions: (1) distributive channels cease progradation due to a drop in sediment transport capacity in an expanded region ahead of the channel; (2) mouth bar aggradation leads to a large flow obstacle to cause the hydraulic jump feedback; (3) hydraulic jump regions are a significant locus of deposition; and (4) the upstream retreat rate is a function of sediment supply and the strength of the jump. We found that simple one-dimensional hydraulic principles such as the choked flow condition and the sequent depth ratio help to explain hydraulic jump initiation and emplaced lobe thickness respectively.

30 CFR 57.8518 - Main and booster fans.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Main and booster fans. 57.8518 Section 57.8518... and Underground § 57.8518 Main and booster fans. (a) All mine main and booster fans installed and used..., or adjustments. (b) In the event of main or booster fan failure due to a malfunction, accident, power...

30 CFR 57.8518 - Main and booster fans.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Main and booster fans. 57.8518 Section 57.8518... and Underground § 57.8518 Main and booster fans. (a) All mine main and booster fans installed and used..., or adjustments. (b) In the event of main or booster fan failure due to a malfunction, accident, power...

30 CFR 57.8518 - Main and booster fans.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main and booster fans. 57.8518 Section 57.8518... and Underground § 57.8518 Main and booster fans. (a) All mine main and booster fans installed and used..., or adjustments. (b) In the event of main or booster fan failure due to a malfunction, accident, power...

30 CFR 57.8518 - Main and booster fans.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Main and booster fans. 57.8518 Section 57.8518... and Underground § 57.8518 Main and booster fans. (a) All mine main and booster fans installed and used..., or adjustments. (b) In the event of main or booster fan failure due to a malfunction, accident, power...

30 CFR 57.8518 - Main and booster fans.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Main and booster fans. 57.8518 Section 57.8518... and Underground § 57.8518 Main and booster fans. (a) All mine main and booster fans installed and used..., or adjustments. (b) In the event of main or booster fan failure due to a malfunction, accident, power...

Simulation test results for lift/cruise fan research and technology aircraft

NASA Technical Reports Server (NTRS)

Bland, M. P.; Konsewicz, R. K.

1976-01-01

A flight simulation program was conducted on the flight simulator for advanced aircraft (FSAA). The flight simulation was a part of a contracted effort to provide a lift/cruise fan V/STOL aircraft mathematical model for flight simulation. The simulated aircraft is a configuration of the Lift/Cruise Fan V/STOL research technology aircraft (RTA). The aircraft was powered by three gas generators driving three fans. One lift fan was installed in the nose of the aircraft, and two lift/cruise fans at the wing root. The thrust of these fans was modulated to provide pitch and roll control, and vectored to provide yaw, side force control, and longitudinal translation. Two versions of the RTA were defined. One was powered by the GE J97/LF460 propulsion system which was gas-coupled for power transfer between fans for control. The other version was powered by DDA XT701 gas generators driving 62 inch variable pitch fans. The flight control system in both versions of the RTA was the same.

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

Food waste as nutrient source in heterotrophic microalgae cultivation.

PubMed

Pleissner, Daniel; Lam, Wan Chi; Sun, Zheng; Lin, Carol Sze Ki

2013-06-01

Glucose, free amino nitrogen (FAN), and phosphate were recovered from food waste by fungal hydrolysis using Aspergillus awamori and Aspergillus oryzae. Using 100g food waste (dry weight), 31.9 g glucose, 0.28 g FAN, and 0.38 g phosphate were recovered after 24h of hydrolysis. The pure hydrolysate has then been used as culture medium and nutrient source for the two heterotrophic microalgae Schizochytrium mangrovei and Chlorella pyrenoidosa, S. mangrovei and C. pyrenoidosa grew well on the complex food waste hydrolysate by utilizing the nutrients recovered. At the end of fermentation 10-20 g biomass were produced rich in carbohydrates, lipids, proteins, and saturated and polyunsaturated fatty acids. Results of this study revealed the potential of food waste hydrolysate as culture medium and nutrient source in microalgae cultivation. Copyright © 2013 Elsevier Ltd. All rights reserved.

A prediction model for lift-fan simulator performance. M.S. Thesis - Cleveland State Univ.

NASA Technical Reports Server (NTRS)

Yuska, J. A.

1972-01-01

The performance characteristics of a model VTOL lift-fan simulator installed in a two-dimensional wing are presented. The lift-fan simulator consisted of a 15-inch diameter fan driven by a turbine contained in the fan hub. The performance of the lift-fan simulator was measured in two ways: (1) the calculated momentum thrust of the fan and turbine (total thrust loading), and (2) the axial-force measured on a load cell force balance (axial-force loading). Tests were conducted over a wide range of crossflow velocities, corrected tip speeds, and wing angle of attack. A prediction modeling technique was developed to help in analyzing the performance characteristics of lift-fan simulators. A multiple linear regression analysis technique is presented which calculates prediction model equations for the dependent variables.

Aircraft Noise Prediction Program (ANOPP) Fan Noise Prediction for Small Engines

NASA Technical Reports Server (NTRS)

Hough, Joe W.; Weir, Donald S.

1996-01-01

The Fan Noise Module of ANOPP is used to predict the broadband noise and pure tones for axial flow compressors or fans. The module, based on the method developed by M. F. Heidmann, uses empirical functions to predict fan noise spectra as a function of frequency and polar directivity. Previous studies have determined the need to modify the module to better correlate measurements of fan noise from engines in the 3000- to 6000-pound thrust class. Additional measurements made by AlliedSignal have confirmed the need to revise the ANOPP fan noise method for smaller engines. This report describes the revisions to the fan noise method which have been verified with measured data from three separate AlliedSignal fan engines. Comparisons of the revised prediction show a significant improvement in overall and spectral noise predictions.

The morphology, processes, and evolution of Monterey Fan: a revisit

USGS Publications Warehouse

Gardner, James V.; Bohannon, Robert G.; Field, Michael E.; Masson, Douglas G.

2010-01-01

Long-range (GLORIA) and mid-range (TOBI) sidescan imagery and seismic-reflection profiles have revealed the surface morphology and architecture of the complete Monterey Fan. The fan has not developed a classic wedge shape because it has been blocked for much of its history by Morro Fracture Zone. The barrier has caused the fan to develop an upper-fan and lower-fan sequence that are distinctly different from one another. The upper-fan sequence is characterized by Monterey and Ascension Channels and associated Monterey Channel-levee system. The lower-fan sequence is characterized by depositional lobes of the Ascension, Monterey, and Sur-Parkington-Lucia systems, with the Monterey depositional lobe being the youngest. Presently, the Monterey depositional lobe is being downcut because the system has reached a new, lower base level in the Murray Fracture Zone. A five-step evolution of Monterey Fan is presented, starting with initial fan deposition in the Late Miocene, about 5.5 Ma. This first stage was one of filling bathymetric lows in the oceanic basement in what was to become the upper-fan segment. The second stage involved filling the bathymetric low on the north side of Morro Fracture Zone, and probably not much sediment was transported beyond the fracture zone. The third stage witnessed sediment being transported around both ends of Morro Fracture Zone and initial sedimentation on the lower-fan segment. During the fourth stage Ascension Channel was diverted into Monterey Channel, thereby cutting off sedimentation to the Ascension depositional lobe.

Numerical Study of Aeroacoustic Sound on Performance of Bladeless Fan

NASA Astrophysics Data System (ADS)

Jafari, Mohammad; Sojoudi, Atta; Hafezisefat, Parinaz

2017-03-01

Aeroacoustic performance of fans is essential due to their widespread application. Therefore, the original aim of this paper is to evaluate the generated noise owing to different geometric parameters. In current study, effect of five geometric parameters was investigated on well performance of a Bladeless fan. Airflow through this fan was analyzed simulating a Bladeless fan within a 2 m×2 m×4 m room. Analysis of the flow field inside the fan and evaluating its performance were obtained by solving conservations of mass and momentum equations for aerodynamic investigations and FW-H noise equations for aeroacoustic analysis. In order to design Bladeless fan Eppler 473 airfoil profile was used as the cross section of this fan. Five distinct parameters, namely height of cross section of the fan, outlet angle of the flow relative to the fan axis, thickness of airflow outlet slit, hydraulic diameter and aspect ratio for circular and quadratic cross sections were considered. Validating acoustic code results, we compared numerical solution of FW-H noise equations for NACA0012 with experimental results. FW-H model was selected to predict the noise generated by the Bladeless fan as the numerical results indicated a good agreement with experimental ones for NACA0012. To validate 3-D numerical results, the experimental results of a round jet showed good agreement with those simulation data. In order to indicate the effect of each mentioned parameter on the fan performance, SPL and OASPL diagrams were illustrated.

Joint SDO and IRIS Observations of a Novel, Hybrid Prominence-Coronal Rain Complex

NASA Astrophysics Data System (ADS)

Liu, Wei; Antolin, Patrick; Sun, Xudong; Gao, Lijia; Vial, Jean-Claude; Gibson, Sarah; Okamoto, Takenori; Berger, Thomas; Uitenbroek, Han; De Pontieu, Bart

2016-10-01

Solar prominences and coronal rain are intimately related phenomena, both involving cool material at chromospheric temperatures within the hot corona and both playing important roles as part of the return flow of the chromosphere-corona mass cycle. At the same time, they exhibit distinct morphologies and dynamics not yet well understood. Quiescent prominences consist of numerous long-lasting, filamentary downflow threads, while coronal rain is more transient and falls comparably faster along well-defined curved paths. We report here a novel, hybrid prominence-coronal rain complex in an arcade-fan geometry observed by SDO/AIA and IRIS, which provides new insights to the underlying physics of such contrasting behaviors. We found that the supra-arcade fan region hosts a prominence sheet consisting of meandering threads with broad line widths. As the prominence material descends to the arcade, it turns into coronal rain sliding down coronal loops with line widths 2-3 times narrower. This contrast suggests that distinct local plasma and magnetic conditions determine the fate of the cool material, a scenario supported by our magnetic field extrapolations from SDO/HMI. Specifically, the supra-arcade fan (similar to those in solar flares; e.g., McKenzie 2013) is likely situated in a current sheet, where the magnetic field is weak and the plasma-beta could be close to unity, thus favoring turbulent flows like those prominence threads. In contrast, the underlying arcade has a stronger magnetic field and most likely a low-beta environment, such that the material is guided along magnetic field lines to appear as coronal rain. We will discuss the physical implications of these observations beyond prominence and coronal rain.

Optimal cooling strategies for players in Australian Tennis Open conditions.

PubMed

Lynch, Grant P; Périard, Julien D; Pluim, Babette M; Brotherhood, John R; Jay, Ollie

2018-03-01

We compared the utility of four cooling interventions for reducing heat strain during simulated tennis match-play in an environment representative of the peak conditions possible at the Australian Open (45°C, <10% RH, 475W/m 2 solar radiation). Nine trained males undertook four trials in a climate chamber, each time completing 4 sets of simulated match-play. During ITF-mandated breaks (90-s between odd-numbered games; 120-s between sets), either iced towels (ICE), an electric fan (FAN dry ), a fan with moisture applied to the skin (FAN wet ), or ad libitum 10°C water ingestion only (CON) was administered. Rectal temperature (T re ), mean skin temperature (T sk ), heart rate (HR), thermal sensation (TS), perceived exertion (RPE) and whole body sweating (WBSR) were measured. After set 3, T re was lower in ICE (38.2±0.3°C) compared to FAN dry (38.7±0.5°C; p=0.02) and CON (38.5±0.5°C; p=0.05), while T re in FAN wet (38.2±0.3°C) was lower than FAN dry (p=0.05). End-exercise T re was lower in ICE (38.1±0.3°C) and FAN wet (38.2±0.4°C) than FAN dry (38.9±0.7°C; p<0.04) and CON (38.8±0.5°C; p<0.04).T sk for ICE (35.3±0.8°C) was lower than all conditions, and T sk for FAN wet (36.6±1.1°C) was lower than FAN dry (38.1±1.3°C; p<0.05). TS for ICE and FAN wet were lower than CON and FAN dry (p<0.05). HR was suppressed in ICE and FAN wet relative to CON and FAN dry (p<0.05). WBSR was greater in FAN dry compared to FAN wet (p<0.01) and ICE (p<0.001). Fan use must be used with skin wetting to be effective in hot/dry conditions. This strategy and the currently recommended ICE intervention both reduced T re by ∼0.5-0.6°C and T sk by ∼1.0-1.5°C while mitigating rises in HR and TS. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Quiet Clean Short-haul Experimental Engine (QCSEE). The aerodynamic and mechanical design of the QCSEE over-the-wing fan

NASA Technical Reports Server (NTRS)

1976-01-01

The aerodynamic and mechanical design of a fixed-pitch 1.36 pressure ratio fan for the over-the-wing (OTW) engine is presented. The fan has 28 blades. Aerodynamically, the fan blades were designed for a composite blade, but titanium blades were used in the experimental fan as a cost savings measure.

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.

9. DETAIL OF THE FAN HOUSE INTERIOR, SHOWING FAN OPENINGS. ...

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

9. DETAIL OF THE FAN HOUSE INTERIOR, SHOWING FAN OPENINGS. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

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.

Reverse Flow Engine Core Having a Ducted Fan with Integrated Secondary Flow Blades

NASA Technical Reports Server (NTRS)

Kisska, Michael K. (Inventor); Princen, Norman H. (Inventor); Kuehn, Mark S. (Inventor); Cosentino, Gary B. (Inventor)

2014-01-01

Secondary air flow is provided for a ducted fan having a reverse flow turbine engine core driving a fan blisk. The fan blisk incorporates a set of thrust fan blades extending from an outer hub and a set of integral secondary flow blades extending intermediate an inner hub and the outer hub. A nacelle provides an outer flow duct for the thrust fan blades and a secondary flow duct carries flow from the integral secondary flow blades as cooling air for components of the reverse flow turbine engine.

Gas Turbine Engine Having Fan Rotor Driven by Turbine Exhaust and with a Bypass

NASA Technical Reports Server (NTRS)

Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

2016-01-01

A gas turbine engine has a core engine incorporating a core engine turbine. A fan rotor is driven by a fan rotor turbine. The fan rotor turbine is in the path of gases downstream from the core engine turbine. A bypass door is moveable from a closed position at which the gases from the core engine turbine pass over the fan rotor turbine, and moveable to a bypass position at which the gases are directed away from the fan rotor turbine. An aircraft is also disclosed.

Advanced Low-Noise Research Fan Stage Design

NASA Technical Reports Server (NTRS)

Neubert, Robert; Bock, Larry; Malmborg, Eric; Owen-Peer, William

1997-01-01

This report describes the design of the Advanced Low-Noise 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 (FEGVs) and core stators. The fan stage design is combined with a nacelle and engine core duct to form a powered fan/nacelle subscale model. This model is intended for use in combined aerodynamic, acoustic, and structural testing in a wind tunnel. The fan has an outer diameter of 22 in. and a hub-to-tip of 0.426 in., which allows the use of existing NASA fan and cowl force balance and rig drive systems. The design parameters were selected to permit valid acoustic and aerodynamic comparisons with the Pratt & Whitney (P&W) 17- and 22-in. rigs previously tested under NASA contract. The fan stage design is described in detail. The results of the design axisymmetric and Navier-Stokes aerodynamic analysis are presented at the critical design conditions. The structural analysis of the fan rotor and attachment is included. 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 FEGV and core stator to minimize noise. A fan/FEGV tone analysis developed separately under NASA contract was used to determine the optimum airfoil counts. The fan stage was matched to the existing nacelle, designed under the previous P&W low-noise contract, to form a fan/nacelle model for wind tunnel testing. It is an axisymmetric nacelle for convenience in testing and analysis. Previous testing confirmed that the nacelle performed as required at various aircraft operating conditions.

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.

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.

30 CFR 57.22208 - Auxiliary fans (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Auxiliary fans (I-A, II-A, III, and V-A mines). 57.22208 Section 57.22208 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... fans (I-A, II-A, III, and V-A mines). (a) Auxiliary fans, except fans used in shops and other areas...

Computational Aerodynamic Simulations of a 1484 ft/sec Tip Speed Quiet High-Speed Fan System Model for Acoustic Methods Assessment and Development

NASA Technical Reports Server (NTRS)

Tweedt, Daniel L.

2014-01-01

Computational Aerodynamic simulations of a 1484 ft/sec tip speed quiet high-speed fan system were performed at five different operating points on the fan operating line, in order to provide detailed internal flow field information for use with fan acoustic prediction methods presently being developed, assessed and validated. The fan system is a sub-scale, low-noise research fan/nacelle model that has undergone experimental testing in the 9- by 15-foot Low Speed Wind Tunnel at the NASA Glenn Research Center. Details of the fan geometry, the computational fluid dynamics methods, the computational grids, and various computational parameters relevant to the numerical simulations are discussed. Flow field results for three of the five operating points simulated are presented in order to provide a representative look at the computed solutions. Each of the five fan aerodynamic simulations involved the entire fan system, which includes a core duct and a bypass duct that merge upstream of the fan system nozzle. As a result, only fan rotational speed and the system bypass ratio, set by means of a translating nozzle plug, were adjusted in order to set the fan operating point, leading to operating points that lie on a fan operating line and making mass flow rate a fully dependent parameter. The resulting mass flow rates are in good agreement with measurement values. Computed blade row flow fields at all fan operating points are, in general, aerodynamically healthy. Rotor blade and fan exit guide vane flow characteristics are good, including incidence and deviation angles, chordwise static pressure distributions, blade surface boundary layers, secondary flow structures, and blade wakes. Examination of the computed flow fields reveals no excessive or critical boundary layer separations or related secondary-flow problems, with the exception of the hub boundary layer at the core duct entrance. At that location a significant flow separation is present. The region of local flow recirculation extends through a mixing plane, however, which for the particular mixing-plane model used is now known to exaggerate the recirculation. In any case, the flow separation has relatively little impact on the computed rotor and FEGV flow fields.

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).

Installation effects on performance of multiple model V/STOL lift fans

NASA Technical Reports Server (NTRS)

Diedrich, J. H.; Clough, N.; Lieblein, S.

1972-01-01

An experimental program was performed in which the individual performance of multiple VTOL model lift fans was measured. The model tested consisted of three 5.5 in. diameter tip-turbine driven model VTOL lift fans mounted chordwise in a two-dimensional wing to simulate a pod-type array. The performance data provided significant insight into possible thrust variations and losses caused by the presence of cover doors, adjacent fuselage panels, and adjacent fans. The effect of a partial loss of drive air supply (simulated gas generator failure) on fan performance was also investigated. The results of the tests demonstrated that lift fan installation variables and hardware can have a significant effect on the thrust of the individual fans.

Computational and experimental study of airflow around a fan powered UVGI lamp

NASA Astrophysics Data System (ADS)

Kaligotla, Srikar; Tavakoli, Behtash; Glauser, Mark; Ahmadi, Goodarz

2011-11-01

The quality of indoor air environment is very important for improving the health of occupants and reducing personal exposure to hazardous pollutants. An effective way of controlling air quality is by eliminating the airborne bacteria and viruses or by reducing their emissions. Ultraviolet Germicidal Irradiation (UVGI) lamps can effectively reduce these bio-contaminants in an indoor environment, but the efficiency of these systems depends on airflow in and around the device. UVGI lamps would not be as effective in stagnant environments as they would be when the moving air brings the bio-contaminant in their irradiation region. Introducing a fan into the UVGI system would augment the efficiency of the system's kill rate. Airflows in ventilated spaces are quite complex due to the vast range of length and velocity scales. The purpose of this research is to study these complex airflows using CFD techniques and validate computational model with airflow measurements around the device using Particle Image Velocimetry measurements. The experimental results including mean velocities, length scales and RMS values of fluctuating velocities are used in the CFD validation. Comparison of these data at different locations around the device with the CFD model predictions are performed and good agreement was observed.

Autogenic dynamics of debris-flow fans

NASA Astrophysics Data System (ADS)

van den Berg, Wilco; de Haas, Tjalling; Braat, Lisanne; Kleinhans, Maarten

2015-04-01

Alluvial fans develop their semi-conical shape by cyclic avulsion of their geomorphologically active sector from a fixed fan apex. These cyclic avulsions have been attributed to both allogenic and autogenic forcings and processes. Autogenic dynamics have been extensively studied on fluvial fans through physical scale experiments, and are governed by cyclic alternations of aggradation by unconfined sheet flow, fanhead incision leading to channelized flow, channel backfilling and avulsion. On debris-flow fans, however, autogenic dynamics have not yet been directly observed. We experimentally created debris-flow fans under constant extrinsic forcings, and show that autogenic dynamics are a fundamental intrinsic process on debris-flow fans. We found that autogenic cycles on debris-flow fans are driven by sequences of backfilling, avulsion and channelization, similar to the cycles on fluvial fans. However, the processes that govern these sequences are unique for debris-flow fans, and differ fundamentally from the processes that govern autogenic dynamics on fluvial fans. We experimentally observed that backfilling commenced after the debris flows reached their maximum possible extent. The next debris flows then progressively became shorter, driven by feedbacks on fan morphology and flow-dynamics. The progressively decreasing debris-flow length caused in-channel sedimentation, which led to increasing channel overflow and wider debris flows. This reduced the impulse of the liquefied flow body to the flow front, which then further reduced flow velocity and runout length, and induced further in-channel sedimentation. This commenced a positive feedback wherein debris flows became increasingly short and wide, until the channel was completely filled and the apex cross-profile was plano-convex. At this point, there was no preferential transport direction by channelization, and the debris flows progressively avulsed towards the steepest, preferential, flow path. Simultaneously, the debris flows started to channelize, forced by increasingly effective concentration of the flow impulse to the flow front, which caused more effective lateral levee formation and an increasingly well-defined channel. This process continued until the debris flows reached their maximum possible extent and the cycle was reverted. Channelization occurred in the absence of erosion, in contrast with fluvial fans. Backfilling and channelization cycles were gradual and symmetric, requiring multiple debris flows to be completed. These results add debris-flow fans to the spectrum of fan-shaped aqueous systems that are affected by autogenic dynamics, now ranging from low-gradient rivers systems to steep-gradient mass-flow fans.

Performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX

NASA Astrophysics Data System (ADS)

Syafiqah, Z.; Amin, N. A. M.; Irwan, Y. M.; Irwanto, M.; Leow, W. Z.; Amelia, A. R.

2017-09-01

A research has been conducted to find the optimum combination for DC fan air cooling system of photovoltaic (PV) panel. During normal operation of PV panel, it is estimated that only 15 % of solar radiation is converted into electrical energy. Meanwhile, the rest of the solar radiation is converted into heat energy which affects the performance of the PV panel. Therefore, the aim of this research is to investigate the performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX. The effect of airflow configuration of DC fan has been investigated. This is to analyze whether the airflow circulation of DC fan cause a change towards the maximum temperature of PV panel. Besides, the impact of varying number of DC fans attached at the back of PV panel is evaluated. The result of airflow circulation of DC fan has been discussed. Meanwhile, with the increment number of DC fans, the PV panel temperature drops significantly. As a conclusion, the optimum number of DC fans is two with the combination of inlet airflow.

An aerodynamic investigation of two 1.83-meter-diameter fan systems designed to drive a subsonic wind tunnel

NASA Technical Reports Server (NTRS)

Page, V. R.; Eckert, W. T.; Mort, K. W.

1977-01-01

An experimental, aerodynamic investigation was made of two 1.83 m diameter fan systems which are being considered for the repowered drive section of the 40- by 80-foot wind tunnel at NASA Ames Research Center. One system was low speed, the other was high speed. The low speed fan was tested at various stagger angles from 32.9 deg to 62.9 deg. At a fan blade stagger angle of 40.8 deg and operating at a tip speed of 1155 m/sec, the low speed fan developed 207.3 m of head. The high speed fan had a design blade stagger angle of 56.2 deg and was tested at this stagger angle only. The high speed fan operating at 191.5 m/sec developed 207.3 m of head. Radial distributions of static pressure coefficients, total pressure coefficients, and angles of swirl are presented. Radial surveys were conducted at four azimuth locations in front of the fan, and repeated downstream of the fan. Data were taken for various flow control devices and for two inlet contraction lengths.

Late Quaternary landscape evolution in the Kunlun Mountains and Qaidam Basin, Northern Tibet: A framework for examining the links between glaciation, lake level changes and alluvial fan formation

USGS Publications Warehouse

Owen, L.A.; Finkel, R.C.; Haizhou, M.; Barnard, P.L.

2006-01-01

The Qaidam Basin in Northern Tibet is one of the largest hyper-arid intermontane basins on Earth. Alluvial fans, pediment surfaces, shorelines and a thick succession of sediments within the basin, coupled with moraines and associated landforms in the adjacent high mountain catchments of the Kunlun Mountains, record a complex history of Late Quaternary paleoenvironmental change and landscape evolution. The region provides an ideal natural laboratory to examine the interaction between tectonics and climate within a continent-continent collision zone, and to quantify rates of landscape evolution as controlled by climate and the associated glacial and hydrological changes in hyper-arid and adjacent high-altitude environments. Geomorphic mapping, analysis of landforms and sediments, and terrestrial cosmogenic radionuclide surface exposure and optically stimulated luminescence dating serve to define the timing of formation of Late Quaternary landforms along the southern and northwestern margins of the Qaidam Basin, and in the Burhan Budai Shan of the Kunlun Mountains adjacent to the basin on the south. These dates provide a framework that suggests links between climatic amelioration, deglaciation, lake desiccation and alluvial fan evolution. At least three glacial advances are defined in the Burham Budai Shan of the Kunlun Mountains. On the northern side of this range these occurred in the penultimate glacial cycle or early in the last glacial cycle, during the Last Glacial Maximum (LGM)/Lateglacial and during the Holocene. On the south side of the range, advances occurred during the penultimate glacial cycle, MIS-3, and possibly the LGM, Lateglacial or Holocene. Several distinct phases of alluvial fan sedimentation are likewise defined. Alluvial fans formed on the southern side of the Kunlun Mountains prior to 200 ka. Ice-contact alluvial fans formed during the penultimate glacial and during MIS-3. Extensive incised alluvial fans that form the main valley fills north of the Burham Budai and extend into the Qaidam Basin are dated to ???30 ka. These ages suggest that there was a period of alluvial fan aggradation and valley filling that persisted until desiccation of the large lakes in the Qaidam Basin post ???30 ka led to base level lowering and active incision of streams into the valley fills. The continued Lateglacial and Holocene desiccation likely led to further degradation of the valley fills. Ice wedge casts in the Qaidam Basin date to ???15 ka, indicating significant Lateglacial climatic amelioration, while Holocene loess deposits north of the Burham Bdudai suggest that aridity has increased in the region since the early Holocene. From these observations, we infer that the major landscape changes within high glaciated mountains and their adjacent hyper-arid intermontane basins, such as the Kunlun Mountains and Qaidam Basin, occur rapidly over millennial timescales during periods of climatic instability. ?? 2006 Elsevier Ltd and INQUA.

30 CFR 57.22205 - Doors on main fans (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Doors on main fans (I-A, II-A, III, and V-A mines). 57.22205 Section 57.22205 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... main fans (I-A, II-A, III, and V-A mines). In mines ventilated by multiple main fans, each main fan...

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.

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.

Big Fans

NASA Image and Video Library

2018-03-05

Shown in this image from NASA's Mars Reconnaissance Orbiter (MRO) are alluvial fans, fan-shaped deposits emerging from regions of steep topography. Alluvial fans on Mars are thought to be ancient and record past episodes of flowing water. This image shows part of one of those fans, which has been eroded. The old stream channels now stand above the rest of the fan as ridges, mostly in the southern (bottom) part of the image. This can occur because the channel materials are more resistant to erosion; perhaps they had larger grains (gravel) or because minerals deposited from the water cemented together. https://photojournal.jpl.nasa.gov/catalog/PIA22332

On the design and structural analysis of jet engine fan blade structures

NASA Astrophysics Data System (ADS)

Amoo, Leye M.

2013-07-01

Progress in the design and structural analysis of commercial jet engine fan blades is reviewed and presented. This article is motivated by the key role fan blades play in the performance of advanced gas turbine jet engines. The fundamentals of the associated physics are emphasized. Recent developments and advancements have led to an increase and improvement in fan blade structural durability, stability and reliability. This article is intended as a high level review of the fan blade environment and current state of structural design to aid further research in developing new and innovative fan blade technologies.

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.

Debris flow deposition and reworking by the Colorado River in Grand Canyon, Arizona

USGS Publications Warehouse

Yanites, Brian J.; Webb, Robert H.; Griffiths, Peter G.; Magirl, Christopher S.

2006-01-01

Flow regulation by large dams affects downstream flow competence and channel maintenance. Debris flows from 740 tributaries in Grand Canyon, Arizona, transport coarse‐grained sediment onto debris fans adjacent to the Colorado River. These debris fans constrict the river to form rapids and are reworked during river flows that entrain particles and transport them downstream. Beginning in 1963, flood control operations of Glen Canyon Dam limited the potential for reworking of aggraded debris fans. We analyzed change in debris fans at the mouths of 75‐Mile and Monument Creeks using photogrammetry of aerial photography taken from 1965 to 2000 and supplemented with ground surveys performed from 1987 to 2005. Our results quantify the debris fan aggradation that resulted from debris flows from 1984 to 2003. Volume, area, and river constriction increased at both debris fans. Profiles of the two debris fans show that net aggradation occurred in the middle of debris fans at stages above maximum dam releases, and surface shape shifted from concave to convex. Dam releases above power plant capacity partially reworked both debris fans, although reworking removed much less sediment than what was added by debris flow deposition. Large dam releases would be required to create additional reworking to limit the rate of debris fan aggradation in Grand Canyon.

Evaluating the Effectiveness of Cooling Vest in a Hot and Humid Environment.

PubMed

Yi, Wen; Zhao, Yijie; Chan, Albert P C

2017-05-01

This study aims to evaluate the effectiveness of a newly designed hybrid cooling vest for construction workers in alleviating heat stress. Two types of cooling vests, namely, a commonly worn Vest A and a newly designed Vest B, were tested in a climatic chamber environment (34.0°C temperature, 60% relative humidity, and 0.4 m s-1 air velocity) using a sweating thermal manikin. Four test scenarios were included: fan off with no phase change materials (PCMs) (Fan-off), fan on with no PCMs (Fan-on), fan off with completely solidified PCMs (PCM + Fan-off), and fan on with completely solidified PCMs (PCM + Fan-on). Test results showed that Vests A and B provided a continuous cooling effect during the 3-h test. The average cooling power for the torso region of Vest B was 67 W, which was higher than that of Vest A (56 W). The addition of PCMs offered a cooling effect of approximately 60 min. Ventilation fans considerably improved the evaporative heat loss compared with the Fan-off condition. The newly designed hybrid cooling vest (Vest B) may be an effective means to reduce heat strain and enhance work performance in a hot and humid environment. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

CFD Models of a Serpentine Inlet, Fan, and Nozzle

NASA Technical Reports Server (NTRS)

Chima, R. V.; Arend, D. J.; Castner, R. S.; Slater, J. W.; Truax, P. P.

2010-01-01

Several computational fluid dynamics (CFD) codes were used to analyze the Versatile Integrated Inlet Propulsion Aerodynamics Rig (VIIPAR) located at NASA Glenn Research Center. The rig consists of a serpentine inlet, a rake assembly, inlet guide vanes, a 12-in. diameter tip-turbine driven fan stage, exit rakes or probes, and an exhaust nozzle with a translating centerbody. The analyses were done to develop computational capabilities for modeling inlet/fan interaction and to help interpret experimental data. Three-dimensional Reynolds averaged Navier-Stokes (RANS) calculations of the fan stage were used to predict the operating line of the stage, the effects of leakage from the turbine stream, and the effects of inlet guide vane (IGV) setting angle. Coupled axisymmetric calculations of a bellmouth, fan, and nozzle were used to develop techniques for coupling codes together and to investigate possible effects of the nozzle on the fan. RANS calculations of the serpentine inlet were coupled to Euler calculations of the fan to investigate the complete inlet/fan system. Computed wall static pressures along the inlet centerline agreed reasonably well with experimental data but computed total pressures at the aerodynamic interface plane (AIP) showed significant differences from the data. Inlet distortion was shown to reduce the fan corrected flow and pressure ratio, and was not completely eliminated by passage through the fan

Pacing of deep marine sedimentation in the middle Eocene synorogenic Ainsa Basin, Spanish Pyrenees: deconvolving a 6myr record of tectonic and climate controls

NASA Astrophysics Data System (ADS)

Mac Niocaill, C.; Cantalejo, B.; Pickering, K. T.; Grant, M.; Johansen, K.

2016-12-01

The Middle Eocene thrust-top Ainsa Basin of Northern Spain preserves world-class exposures of deep-marine submarine fan and related deposits. Detailed paleomagnetic, micropaleontologic, and time-series analysis enable us to deconvolve, for the first time in any ancient deep-marine basin worldwide, both the pacing on deposition of the fine-grained interfan sediments and the main sandbodies (submarine fans) through the history of the deep-marine basin. Our magnetostratigraphy and faunal constraints provide a chronological framework for sedimentation in the basin. We use time-series analysis of a range of geochemical and sedimentologic data to identify likely climatic signals in the sedimentary archive. This has enabled us to test the likely importance of climate versus tectonics in controlling deposition. We show that the fine-grained interfan sedimentation preserves a dominant Milankovitch-like cyclicity, whereas the sandbodies (fans) reflect a complex interplay of controls such as tectonics and climate in the sediment source area, including shallow-marine staging areas for sediment redeposition into deeper water. These results not only provide critical information about the timing of substantial coarse clastic delivery into the Ainsa Basin but also give constraints on sediment flux over a 6 Myr window.

Large Scale Application of Vibration Sensors for Fan Monitoring at Commercial Layer Hen Houses

PubMed Central

Chen, Yan; Ni, Ji-Qin; Diehl, Claude A.; Heber, Albert J.; Bogan, Bill W.; Chai, Li-Long

2010-01-01

Continuously monitoring the operation of each individual fan can significantly improve the measurement quality of aerial pollutant emissions from animal buildings that have a large number of fans. To monitor the fan operation by detecting the fan vibration is a relatively new technique. A low-cost electronic vibration sensor was developed and commercialized. However, its large scale application has not yet been evaluated. This paper presents long-term performance results of this vibration sensor at two large commercial layer houses. Vibration sensors were installed on 164 fans of 130 cm diameter to continuously monitor the fan on/off status for two years. The performance of the vibration sensors was compared with fan rotational speed (FRS) sensors. The vibration sensors exhibited quick response and high sensitivity to fan operations and therefore satisfied the general requirements of air quality research. The study proved that detecting fan vibration was an effective method to monitor the on/off status of a large number of single-speed fans. The vibration sensor itself was $2 more expensive than a magnetic proximity FRS sensor but the overall cost including installation and data acquisition hardware was $77 less expensive than the FRS sensor. A total of nine vibration sensors failed during the study and the failure rate was related to the batches of product. A few sensors also exhibited unsteady sensitivity. As a new product, the quality of the sensor should be improved to make it more reliable and acceptable. PMID:22163544

Investigation of an Axial Fan—Blade Stress and Vibration Due to Aerodynamic Pressure Field and Centrifugal Effects

NASA Astrophysics Data System (ADS)

Xu, Cheng; Amano, Ryoichi Samuel; Lee, Eng Kwong

A 1.829m (6ft) diameter industrial large flow-rate axial fan operated at 1770rpm was studied experimentally in laboratory conditions. The flow characteristics on the fan blade surfaces were investigated by measuring the pressure distributions on the blade suction and pressure surfaces and the results were discussed by comparing with analytical formulations and CFD. Flow visualizations were also performed to validate the flow characteristics near the blade surface and it was demonstrated that the flow characteristics near the fan blade surface were dominated by the centrifugal force of the fan rotation which resulted in strong three-dimensional flows. The time-dependent pressure measurement showed that the pressure oscillations on the fan blade were significantly dominated by vortex shedding from the fan blades. It was further demonstrated that the pressure distributions during the fan start-up were highly unsteady, and the main frequency variation of the static pressure was much smaller than the fan rotational frequency. The time-dependent pressure measurement when the fan operated at a constant speed showed that the magnitude of the blade pressure variation with time and the main variation frequency was much smaller than the fan rotational frequency. The pressure variations that were related to the vortex shedding were slightly smaller than the fan rotational frequency. The strain gages were used to measure the blade stress and the results were compared with FEA results.

Are the dimensions of submarine lobe systems independent of allogenic factors?

NASA Astrophysics Data System (ADS)

Prélat, A.; Covault, J. A.; Hodgson, D. M.; Fildani, A.; Flint, S. S.

2010-05-01

Submarine lobe dimensions from six different systems are compared: 1) the exhumed Permian Fan 3 lobe complex of the Tanqua Karoo, South Africa; 2) the modern Amazon fan channel-mouth lobe complex, offshore Brazil; 3) a portion of the modern distal Zaïre fan, offshore Angola / Congo; 4) a Pleistocene fan of the Kutai Basin, subsurface offshore Indonesia; 5) the modern Golo system, offshore east Corsica, France; and 6) a lobe complex deposited in the shallow subsurface, offshore Nigeria. These six systems have significantly different source-to-sink configurations (shelf dimension and slope topography), sediment supply characteristics (calibre and rate), tectonic settings, (palaeo) latitude, and delivery systems. Despite these differences, the lobe deposits share similar geometric and dimensional characteristics. Lobes are grouped into two distinct populations of geometries that can be related to basin-floor topography. The first population corresponds to areally extensive but thin lobes (average width 14 km × length 35 km × thickness 12 m) that were deposited onto low relief basin floor areas, like the Tanqua Karoo, the Amazon and the Zaïre systems. The second population corresponds to areally smaller but thicker lobes (average width 5 km × length 8 km × thickness 30 m) that were deposited into settings with higher amplitude of relief, like in the Corsican trough, the Kutai basin, and offshore Nigeria. Basin floor topography confining the lobes can be very subtle, and only occur on one side of the system. The two populations of lobe types, however, share similar volumes, in the order of 1 or 2 km3. The largest lobes are observed in the Zaïre fan, where the average lobe volume reaches 3.3 km3 and the smallest lobes are observed in the Corsican trough where the average lobe volume is 0.4 km3. This variation in lobe volume is minor when compared to the variation observed in present-day up-dip drainage systems, which provide sediment to the deep-water depositional systems and their lobes. This suggests that there is a limit to the total volume of sediment that individual lobes can reach before they shift to a new locus of deposition. In otherwords, big systems do not build big lobes, rather more lobes per unit time. Indeed, in the Amazon and the Zaïre systems, lobe life span is estimated to be 600 and 1450 years, respectively, whereas in the Corsican Golo system, lobe life span is ~ 10 times longer, around 10 to 14 × 103 years. A fundamental control on lobe volume is the propensity for flows to find the lowest topography. We postulate that a fundamental control on all distributive systems is the ratio of lobe thickness to feeder channel depth. The surface gradient from the feeder channel base and lobe top will tend to reduce through time as a lobe builds. This is not sustainable, and when a steeper lateral gradient is present a new depositional low will be used for flows to fill.

High-Resolution Geologic Mapping of Martian Terraced Fan Deposits

NASA Astrophysics Data System (ADS)

Wolak, J. M.; Patterson, A. B.; Smith, S. D.; Robbins, N. N.

2018-06-01

This abstract documents our initial progress (year 1) mapping terraced fan features on Mars. Our objective is to investigate the role of fluids during fan formation and produce the first high-resolution geologic map (1:18k) of a terraced fan.

Observational Analysis of Coronal Fans

NASA Technical Reports Server (NTRS)

Talpeanu, D.-C.; Rachmeler, L; Mierla, Marilena

2017-01-01

Coronal fans (see Figure 1) are bright observational structures that extend to large distances above the solar surface and can easily be seen in EUV (174 angstrom) above the limb. They have a very long lifetime and can live up to several Carrington rotations (CR), remaining relatively stationary for many months. Note that they are not off-limb manifestation of similarly-named active region fans. The solar conditions required to create coronal fans are not well understood. The goal of this research was to find as many associations as possible of coronal fans with other solar features and to gain a better understanding of these structures. Therefore, we analyzed many fans and created an overview of their properties. We present the results of this statistical analysis and also a case study on the longest living fan.

Extended frequency turbofan model

NASA Technical Reports Server (NTRS)

Mason, J. R.; Park, J. W.; Jaekel, R. F.

1980-01-01

The fan model was developed using two dimensional modeling techniques to add dynamic radial coupling between the core stream and the bypass stream of the fan. When incorporated into a complete TF-30 engine simulation, the fan model greatly improved compression system frequency response to planar inlet pressure disturbances up to 100 Hz. The improved simulation also matched engine stability limits at 15 Hz, whereas the one dimensional fan model required twice the inlet pressure amplitude to stall the simulation. With verification of the two dimensional fan model, this program formulated a high frequency F-100(3) engine simulation using row by row compression system characteristics. In addition to the F-100(3) remote splitter fan, the program modified the model fan characteristics to simulate a proximate splitter version of the F-100(3) engine.

The Effect of Bypass Nozzle Exit Area on Fan Aerodynamic Performance and Noise in a Model Turbofan Simulator

NASA Technical Reports Server (NTRS)

Hughes, Christopher E.; Podboy, Gary, G.; Woodward, Richard P.; Jeracki, Robert, J.

2013-01-01

The design of effective new technologies to reduce aircraft propulsion noise is dependent on identifying and understanding the noise sources and noise generation mechanisms in the modern turbofan engine, as well as determining their contribution to the overall aircraft noise signature. Therefore, a comprehensive aeroacoustic wind tunnel test program was conducted called the Fan Broadband Source Diagnostic Test as part of the NASA Quiet Aircraft Technology program. The test was performed in the anechoic NASA Glenn 9- by 15-Foot Low Speed Wind Tunnel using a 1/5 scale model turbofan simulator which represented a current generation, medium pressure ratio, high bypass turbofan aircraft engine. The investigation focused on simulating in model scale only the bypass section of the turbofan engine. The test objectives were to: identify the noise sources within the model and determine their noise level; investigate several component design technologies by determining their impact on the aerodynamic and acoustic performance of the fan stage; and conduct detailed flow diagnostics within the fan flow field to characterize the physics of the noise generation mechanisms in a turbofan model. This report discusses results obtained for one aspect of the Source Diagnostic Test that investigated the effect of the bypass or fan nozzle exit area on the bypass stage aerodynamic performance, specifically the fan and outlet guide vanes or stators, as well as the farfield acoustic noise level. The aerodynamic performance, farfield acoustics, and Laser Doppler Velocimeter flow diagnostic results are presented for the fan and four different fixed-area bypass nozzle configurations. The nozzles simulated fixed engine operating lines and encompassed the fan stage operating envelope from near stall to cruise. One nozzle was selected as a baseline reference, representing the nozzle area which would achieve the design point operating conditions and fan stage performance. The total area change from the smallest to the largest nozzle was 12.9 percent of the baseline nozzle area. The results will show that there are significant changes in aerodynamic performance and farfield acoustics as the fan nozzle area is increased. The weight flow through the fan model increased between 7 and 9 percent, the fan and stage pressure dropped between 8 and 10 percent, and the adiabatic efficiency increased between 2 and 3 percent--the magnitude of the change dependent on the fan speed. Results from force balance measurements of fan and outlet guide vane thrust will show that as the nozzle exit area is increased the combined thrust of the fan and outlet guide vanes together also increases, between 2 and 3.5 percent, mainly due to the increase in lift from the outlet guide vanes. In terms of farfield acoustics, the overall sound power level produced by the fan stage dropped nearly linearly between 1 dB at takeoff condition and 3.5 dB at approach condition, mainly due to a decrease in the broadband noise levels. Finally, fan swirl angle survey and Laser Doppler Velocimeter mean velocity and turbulence data obtained in the fan wake will show that the swirl angles and turbulence levels within the wake decrease as the fan nozzle area increases, which helps to explain the drop in the fan broadband noise at all fan speeds.

Multi-objective optimization design and experimental investigation of centrifugal fan performance

NASA Astrophysics Data System (ADS)

Zhang, Lei; Wang, Songling; Hu, Chenxing; Zhang, Qian

2013-11-01

Current studies of fan performance optimization mainly focus on two aspects: one is to improve the blade profile, and another is only to consider the influence of single impeller structural parameter on fan performance. However, there are few studies on the comprehensive effect of the key parameters such as blade number, exit stagger angle of blade and the impeller outlet width on the fan performance. The G4-73 backward centrifugal fan widely used in power plants is selected as the research object. Based on orthogonal design and BP neural network, a model for predicting the centrifugal fan performance parameters is established, and the maximum relative errors of the total pressure and efficiency are 0.974% and 0.333%, respectively. Multi-objective optimization of total pressure and efficiency of the fan is conducted with genetic algorithm, and the optimum combination of impeller structural parameters is proposed. The optimized parameters of blade number, exit stagger angle of blade and the impeller outlet width are seperately 14, 43.9°, and 21 cm. The experiments on centrifugal fan performance and noise are conducted before and after the installation of the new impeller. The experimental results show that with the new impeller, the total pressure of fan increases significantly in total range of the flow rate, and the fan efficiency is improved when the relative flow is above 75%, also the high efficiency area is broadened. Additionally, in 65% -100% relative flow, the fan noise is reduced. Under the design operating condition, total pressure and efficiency of the fan are improved by 6.91% and 0.5%, respectively. This research sheds light on the considering of comprehensive effect of impeller structrual parameters on fan performance, and a new impeller can be designed to satisfy the engineering demand such as energy-saving, noise reduction or solving air pressure insufficiency for power plants.

Quaternary alluvial fans of Ciudad Juárez, Chihuahua, northern México: OSL ages and implications for climatic history of the region

USGS Publications Warehouse

Zúñiga de León, David; Kershaw, Stephen; Mahan, Shannon

2016-01-01

Alluvial fans formed from sediments derived from erosion of the Juárez Mountains in northernmost México have a significant flood impact on the Ciudad Juárez, which is built on the fan system. The northern part of Ciudad Juárez is the most active; further south, older parts of the fan, upon which the rest of the city is built, were largely eroded by natural processes prior to human habitation and subsequently modified only recently by human construction. Three aeolian sand samples, collected from the uppermost (youngest) parts of the fan system in the city area, in places where human intervention has not disturbed the sediment, and constrain the latest dates of fan building. Depositional ages of the Quaternary alluvial fans were measured using Optically Stimulated Luminescence (OSL) on aeolian sands that have inter-fingered with alluvial fan material. These dates are: a) sample P1, 31 ka; b) sample P2, 41 ka; c) sample P3, 74 ka, between Oxygen Isotope Stages (OIS) 3 to 5. They demonstrate that fan development, in the area now occupied by the city, terminated in the Late Pleistocene, immediately after what we interpret to have been an extended period of erosion without further deposition, lasting from the Late Pleistocene to Holocene. The three dates broadly correspond to global glacial periods, implying that the cool, dry periods may reflect periods of aeolian transport in northern México in between phases that were wetter to form the alluvial fans. Alluvial fan margins inter-finger with fluvial terrace sediments derived from the Río Bravo, indicating an additional component of fan dissection by Río Bravo lateral erosion, presumed to be active during earlier times than our OSL ages, but these are not yet dated. Further dating is required to ascertain the controls on the fan and fluvial system.

Tectonic and climatic controls on fan systems: The Kohrud mountain belt, Central Iran

NASA Astrophysics Data System (ADS)

Jones, Stuart J.; Arzani, Nasser; Allen, Mark B.

2014-04-01

Late Pleistocene to Holocene fans of the Kohrud mountain belt (Central Iran) illustrate the problems of differentiating tectonic and climatic drivers for the sedimentary signatures of alluvial fan successions. It is widely recognised that tectonic processes create the topography that causes fan development. The existence and position of fans along the Kohrud mountain belt, NE of Esfahan, are controlled by faulting along the Qom-Zefreh fault system and associated fault zones. These faults display moderate amounts of historical and instrumental seismicity, and so may be considered to be tectonically active. However, fluvial systems on the fans are currently incising in response to low Gavkhoni playa lake levels since the mid-Holocene, producing incised gullies on the fans up to 30 m deep. These gullies expose an interdigitation of lake deposits (dominated by fine-grained silts and clays with evaporites) and coarse gravels that characterise the alluvial fan sediments. The boundaries of each facies are mostly sharp, with fan sediments superimposed on lake sediments with little to no evidence of reworking. In turn, anhydrite-glauberite, mirabilite and halite crusts drape over the gravels, recording a rapid return to still water, shallow ephemeral saline lake sedimentation. Neither transition can be explained by adjustment of the hinterland drainage system after tectonic uplift. The potential influence in Central Iran of enhanced monsoons, the northward drift of the Intertopical Convergence Zone (ITCZ) and Mediterranean climates for the early Holocene (~ 6-10 ka) point to episodic rainfall (during winter months) associated with discrete high magnitude floods on the fan surfaces. The fan sediments were deposited under the general influence of a highstand playa lake whose level was fluctuating in response to climate. This study demonstrates that although tectonism can induce fan development, it is the sensitive balance between aridity and humidity resulting from changes in the climate regime of Central Iran that influences the nature of fan sequences and how they interrelate to associated facies.

Timing and nature of alluvial fan development along the Chajnantor Plateau, northern Chile

NASA Astrophysics Data System (ADS)

Cesta, Jason M.; Ward, Dylan J.

2016-11-01

Alluvial systems in the Atacama Desert provide a unique opportunity to elucidate the sedimentary response to climate variability, particularly changes in precipitation, in hyperarid environments. Alluvial fans along the eastern margin of the Salar de Atacama, adjacent to the Chajnantor Plateau in the Atacama Desert of northern Chile, provide an archive of climate-modulated sediment transfer and erosion at an extreme of Earth's climate. Three regional alluvial fan surfaces (Qf1 [oldest] to Qf3 [youngest]) were mapped along the western flank of the Chajnantor Plateau. The alluvial fans were examined with geomorphic and terrestrial cosmogenic 36Cl surface exposure dating methods to define the timing of alluvial fan formation and to determine the role of climatic processes on fan development in a hyperarid environment. Alluvial fans in the study area are comprised of hyperconcentrated flow and boulder-rich debris flow deposits that reflect deposition transitioning between cohesive and noncohesive regimes. Alluvial fan surfaces yield exposure ages that range from 49.6 ± 4.4 to 194 ± 12 ka, while debris flow boulders yield exposure ages ranging from 12.4 ± 2.1 to 229 ± 53 ka. Cosmogenic 36Cl exposure ages indicate that abandonment of alluvial fan surfaces Qf1, Qf2, and Qf3 date to 175 ± 22.6 ka (MIS 6), 134.5 ± 9.18 ka (MIS 6), and 20.07 ± 6.26 ka (MIS 2), respectively. A 36Cl concentration-depth profile through alluvial fan Qf1 suggests a simple depositional history with minimal nuclide inheritance implying relatively rapid aggradation (6 m in ca. 25 kyr) followed by surface abandonment ca. 180-200 ka. Our data support a strong climatic control on alluvial fan evolution in the region, and we propose that the alluvial fans along the margins of the Salar de Atacama form according to the humid model of fan formation.

Flow performance of highly loaded axial fan with bowed rotor blades

NASA Astrophysics Data System (ADS)

Chen, L.; Liu, X. J.; Yang, A. L.; Dai, R.

2013-12-01

In this paper, a partial bowed rotor blade was proposed for a newly designed high loaded axial fan. The blade was positively bowed 30 degrees from hub to 30 percent spanwise position. Flows of radial blade and bowed blade fans were numerically compared for various operation conditions. Results show that the fan's performance is improved. At the designed condition with flow coefficient of 0.52, the efficiency of the bowed blade fan is increased 1.44% and the static pressure rise is increased 11%. Comparing the flow structures, it can be found that the separated flow in the bowed fan is reduced and confined within 20 percent span, which is less than the 35 percent in the radial fan. It means that the bowed blade generates negative blade force and counteracts partial centrifugal force. It is alleviates the radial movements of boundary layers in fan's hub region. Flow losses due to 3D mixing are reduced in the rotor. Inlet flow to downstream stator is also improved.

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.

Small fan-in is beautiful

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

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 obtainedmore » 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.« less

Computational Aerodynamic Simulations of an 840 ft/sec Tip Speed Advanced Ducted Propulsor Fan System Model for Acoustic Methods Assessment and Development

NASA Technical Reports Server (NTRS)

Tweedt, Daniel L.

2014-01-01

Computational Aerodynamic simulations of an 840 ft/sec tip speed, Advanced Ducted Propulsor fan system were performed at five different operating points on the fan operating line, in order to provide detailed internal flow field information for use with fan acoustic prediction methods presently being developed, assessed and validated. The fan system is a sub-scale, lownoise research fan/nacelle model that has undergone extensive experimental testing in the 9- by 15- foot Low Speed Wind Tunnel at the NASA Glenn Research Center, resulting in quality, detailed aerodynamic and acoustic measurement data. Details of the fan geometry, the computational fluid dynamics methods, the computational grids, and various computational parameters relevant to the numerical simulations are discussed. Flow field results for three of the five operating conditions simulated are presented in order to provide a representative look at the computed solutions. Each of the five fan aerodynamic simulations involved the entire fan system, excluding a long core duct section downstream of the core inlet guide vane. As a result, only fan rotational speed and system bypass ratio, set by specifying static pressure downstream of the core inlet guide vane row, were adjusted in order to set the fan operating point, leading to operating points that lie on a fan operating line and making mass flow rate a fully dependent parameter. The resulting mass flow rates are in good agreement with measurement values. The computed blade row flow fields for all five fan operating points are, in general, aerodynamically healthy. Rotor blade and fan exit guide vane flow characteristics are good, including incidence and deviation angles, chordwise static pressure distributions, blade surface boundary layers, secondary flow structures, and blade wakes. Examination of the computed flow fields reveals no excessive boundary layer separations or related secondary-flow problems. A few spanwise comparisons between computational and measurement data in the bypass duct show that they are in good agreement, thus providing a partial validation of the computational results.

Reconstructing the transport history of pebbles on Mars

PubMed Central

Szabó, Tímea; Domokos, Gábor; Grotzinger, John P.; Jerolmack, Douglas J.

2015-01-01

The discovery of remarkably rounded pebbles by the rover Curiosity, within an exhumed alluvial fan complex in Gale Crater, presents some of the most compelling evidence yet for sustained fluvial activity on Mars. While rounding is known to result from abrasion by inter-particle collisions, geologic interpretations of sediment shape have been qualitative. Here we show how quantitative information on the transport distance of river pebbles can be extracted from their shape alone, using a combination of theory, laboratory experiments and terrestrial field data. We determine that the Martian basalt pebbles have been carried tens of kilometres from their source, by bed-load transport on an alluvial fan. In contrast, angular clasts strewn about the surface of the Curiosity traverse are indicative of later emplacement by rock fragmentation processes. The proposed method for decoding transport history from particle shape provides a new tool for terrestrial and planetary sedimentology. PMID:26460507

Experimental Evaluation of Turning Vane Designs for High-speed and Coupled Fan-drive Corners of 0.1-scale Model of NASA Lewis Research Center's Proposed Altitude Wind Tunnel

NASA Technical Reports Server (NTRS)

Gelder, Thomas F.; Moore, Royce D.; Shyne, Rickey J.; Boldman, Donald R.

1987-01-01

Two turning vane designs were experimentally evaluated for the fan-drive corner (corner 2) coupled to an upstream diffuser and the high-speed corner (corner 1) of the 0.1 scale model of NASA Lewis Research Center's proposed Altitude Wind Tunnel. For corner 2 both a controlled-diffusion vane design (vane A4) and a circular-arc vane design (vane B) were studied. The corner 2 total pressure loss coefficient was about 0.12 with either vane design. This was about 25 percent less loss than when corner 2 was tested alone. Although the vane A4 design has the advantage of 20 percent fewer vanes than the vane B design, its vane shape is more complex. The effects of simulated inlet flow distortion on the overall losses for corner 1 or 2 were small.

Rotor redesign for a highly loaded 1800 ft/sec tip speed fan. 3: Laser Doppler velocimeter report

NASA Technical Reports Server (NTRS)

Harvey, W. B.; Hobbs, D. E.; Lee, D.; Williams, M. C.; Williams, K. F.

1982-01-01

Laser Doppler velocimeter (LDV) techniques were employed for testing a highly loaded, 550 m/sec (1800 ft/sec) tip speed, test fan stage, the objective to provide detailed mapping of the upstream, intrablade, and downstream flowfields of the rotor. Intrablade LDV measurements of velocity and flow angle were obtained along four streamlines passing through the leading edge at 45%, 69%, 85%, and 95% span measured from hub to tip, at 100% of design speed, peak efficiency; 100% speed, near surge; and 95% speed, peak efficiency. At the design point, most passages appeared to have a strong leading edge shock, which moved forward with increasing strength near surge and at part speeds. The flow behind the shock was of a complex mixed subsonic and supersonic form. The intrablade flowfields were found to be significantly nonperiodic at 100% design speed, peak efficiency.

A review of the sedimentology of the Early Proterozoic Pretoria Group, Transvaal Sequence, South Africa: implications for tectonic setting

NASA Astrophysics Data System (ADS)

Eriksson, P. G.; Schreiber, U. M.; van der Neut, M.

The sedimentary rocks of the Early Proterozoic Pretoria Group form the floor rocks to teh 2050 M.a. Bushveld Complex. An overall alluvial fan-fan-delta - lacustrine palaeoenvironmental model is postulated for the Pretoria Group. This model is compatible with a continental half-graben tectonic setting, with steep footwall scarps on the southern margin and a lower gradient hanging wall developed to the north. The latter provided much of the basin-fill detritus. It is envisaged that the southern boundary fault system migrated southwards by footwall collapse as sedimentation continued. Synsedimentary mechanical rifting, associated with alluvial and deltaic sedimentation (Rooihoogte-Strubenkop Formations) was followed by thermal subsidence, with concomitant transgressive lacustrine deposition (Daspoort-Magaliesberg Formations). The proposed half-graben basin was probably related to the long-lived Thabazimbi-Murchison and Sugarbush-Barberton lineaments, which bound the preserved outcrops of the Pretoria Group.

Use of the Logistics Composite Model to Evaluate Avionics Availability.

DTIC Science & Technology

1981-07-01

66 FANM - - 2 8 FANP 5 22 1 21 FANR 2 6 - - FANU 1o 39 1 1 FANW 3 8 1 1 FANZ - - 2 2 FAN4 3 20 2 ŕ FAN6 4 17 - - FAN9 4 7 2 6 FAPA 4 24 6 38 FAPB I I...FAM5 8 20 FAM6 3 5 FAM7 1 1 FANE 2 FANK 2 31 FANP 7 FANU 6 7 FANW 1 8 FANZ 1 FAN4 2 31 FAN6 3 4 FAN9 2 8 FAPA 9 47 FAPE 1 17 FAPH 19 72 FAPJ I I FAPK

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.

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.

NASA/Navy life/cruise fan preliminary design report

NASA Technical Reports Server (NTRS)

1975-01-01

Preliminary design studies were performed to define a turbotip lift/cruise fan propulsion system for a Navy multimission aircraft. The fan is driven by the exhausts of the YJ97-GE-100 turbojet or a 20 percent Growth J97 configuration as defined during the studies. The LCF459 fan configuration defined has a tip diameter of 1.50 meters (59.0 inches) and develops a design point thrust of 75,130 N (16,890 lbs) at a fan pressure ratio of 1.319. The fan has an estimated weight of 386 kg (850 lbs). Trade studies performed to define the selected configuration are described.

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.

Use of TOPSAR digital elevation data to determine the 3-dimensional shape of an alluvial fan

NASA Technical Reports Server (NTRS)

Farr, Tom G.

1995-01-01

Landforms in arid regions record the interplay between tectonic forces and climate. Alluvial fans are a common landform in desert regions where the rate of uplift is greater than weathering or sedimentation. Changes in uplift rate or climatic conditions can lead to isolation of the currently forming fan surface through entrenchment and construction of another fan either further from the mountain front (decreased uplift or increased runoff) or closer to the mountain front (increased uplift or decreased runoff). Thus, many alluvial fans are made up of a mosaic of fan units of different age, some older than 1 million years. For this reason, determination of the stages of fan evolution can lead to a history of uplift and runoff. In an attempt to separate the effects of tectonic (uplift) and climatic (weathering, runoff, sedimentation) processes on the shapes of alluvial fan units, a modified conic equation developed by Troeh (1965) was fitted to TOPSAR digital topographic data for the Trail Canyon alluvial fan in Death Valley, California. This allows parameters for the apex position, slope, and radial curvature to be compared with unit age.

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.

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.

Acoustic Measurements of an Uninstalled Spacecraft Cabin Ventilation Fan Prototype

NASA Technical Reports Server (NTRS)

Koch, L. Danielle; Brown, Clifford A.; Shook, Tony D.; Winkel, James; Kolacz, John S.; Podboy, Devin M.; Loew, Raymond A.; Mirecki, Julius H.

2012-01-01

Sound pressure measurements were recorded for a prototype of a spacecraft cabin ventilation fan in a test in the NASA Glenn Acoustical Testing Laboratory. The axial fan is approximately 0.089 m (3.50 in.) in diameter and 0.223 m (9.00 in.) long and has nine rotor blades and eleven stator vanes. At design point of 12,000 rpm, the fan was predicted to produce a flow rate of 0.709 cu m/s (150 cfm) and a total pressure rise of 925 Pa (3.72 in. of water) at 12,000 rpm. While the fan was designed to be part of a ducted atmospheric revitalization system, no attempt was made to throttle the flow or simulate the installed configuration during this test. The fan was operated at six speeds from 6,000 to 13,500 rpm. A 13-microphone traversing array was used to collect sound pressure measurements along two horizontal planes parallel to the flow direction, two vertical planes upstream of the fan inlet and two vertical planes downstream of the fan exhaust. Measurements indicate that sound at blade passing frequency harmonics contribute significantly to the overall audible noise produced by the fan at free delivery conditions.

Preliminary Aerodynamic Investigation of Fan Rotor Blade Morphing

NASA Technical Reports Server (NTRS)

Tweedt, Daniel L.

2012-01-01

Various new technologies currently under development may enable controlled blade shape variability, or so-called blade morphing, to be practically employed in aircraft engine fans and compressors in the foreseeable future. The current study is a relatively brief, preliminary computational fluid dynamics investigation aimed at partially demonstrating and quantifying the aerodynamic potential of fan rotor blade morphing. The investigation is intended to provide information useful for near-term planning, as well as aerodynamic solution data sets that can be subsequently analyzed using advanced acoustic diagnostic tools, for the purpose of making fan noise comparisons. Two existing fan system models serve as baselines for the investigation: the Advanced Ducted Propulsor fan with a design tip speed of 806 ft/sec and a pressure ratio of 1.294, and the Source Diagnostic Test fan with a design tip speed of 1215 ft/sec and a pressure ratio of 1.470. Both are 22-in. sub-scale, low-noise research fan/nacelle models that have undergone extensive experimental testing in the 9- by 15-foot Low Speed Wind Tunnel at the NASA Glenn Research Center. The study, restricted to fan rotor blade morphing only, involves a fairly simple blade morphing technique. Specifically, spanwise-linear variations in rotor blade-section setting angle are applied to alter the blade shape; that is, the blade is linearly retwisted from hub to tip. Aerodynamic performance comparisons are made between morphed-blade and corresponding baseline configurations on the basis of equal fan system thrust, where rotor rotational speed for the morphed-blade fan is varied to change the thrust level for that configuration. The results of the investigation confirm that rotor blade morphing could be a useful technology, with the potential to enable significant improvements in fan aerodynamic performance. Even though the study is very limited in scope and confined to simple geometric perturbations of two existing fan systems, the aerodynamic effectiveness of blade morphing is demonstrated by the configurations analyzed. In particular, for the Advanced Ducted Propulsor fan it is demonstrated that the performance levels of the original variable-pitch baseline design can be achieved using blade morphing instead of variable pitch, and for the Source Diagnostic Test fan the performance at important off-design operating points is substantially increased with blade morphing.

Late Quaternary faulting in the Vallo di Diano basin (southern Apennines, Italy)

NASA Astrophysics Data System (ADS)

Villani, F.; Pierdominici, S.; Cinti, F. R.

2009-12-01

The Vallo di Diano is the largest Quaternary extensional basin in the southern Apennines thrust-belt axis (Italy). This portion of the chain is highly seismic and is currently subject to NE-extension, which triggers large (M> 6) normal-faulting earthquakes along NW-trending faults. The eastern edge of the Vallo di Diano basin is bounded by an extensional fault system featuring three main NW-trending, SW-dipping, right-stepping, ~15-17 km long segments (from north to south: Polla, Atena Lucana-Sala Consilina and Padula faults). Holocene activity has been documented so far only for the Polla segment. We have therefore focused our geomorphological and paleoseismological study on the southern portion of the system, particularly along the ~ 4 km long Atena Lucana-Sala Consilina and Padula faults overlap zone. The latter is characterized by a complex system of coalescent alluvial fans, Middle Pleistocene to Holocene in age. Here we recognized a > 4 km long and 0.5-1.4 km wide set of scarps (ranging in height between 1 m and 2.5 m) affecting Late Pleistocene - Holocene alluvial fans. In the same area, two Late Pleistocene volcanoclastic layers at the top of an alluvial fan exposed in a quarry are affected by ~ 1 m normal displacements. Moreover, a trench excavated across a 2 m high scarp affecting a Holocene fan revealed warping of Late Holocene debris flow deposits, with a total vertical throw of about 0.3 m. We therefore infer the overlap zone of the Atena Lucana-Sala Consilina and Padula faults is a breached relay ramp, generated by hard-linkage of the two fault segments since Late Pleistocene. This ~ 32 km long fault system is active and is capable of generating Mw ≥6.5 earthquakes.

Shape memory alloy actuation for a variable area fan nozzle

NASA Astrophysics Data System (ADS)

Rey, Nancy; Tillman, Gregory; Miller, Robin M.; Wynosky, Thomas; Larkin, Michael J.; Flamm, Jeffrey D.; Bangert, Linda S.

2001-06-01

The ability to control fan nozzle exit area is an enabling technology for next generation high-bypass-ratio turbofan engines. Performance benefits for such designs are estimated at up to 9% in thrust specific fuel consumption (TSFC) relative to current fixed-geometry engines. Conventionally actuated variable area fan nozzle (VAN) concepts tend to be heavy and complicated, with significant aircraft integration, reliability and packaging issues. The goal of this effort was to eliminate these undesirable features and formulate a design that meets or exceeds leakage, durability, reliability, maintenance and manufacturing cost goals. A Shape Memory Alloy (SMA) bundled cable actuator acting to move an array of flaps around the fan nozzle annulus is a concept that meets these requirements. The SMA bundled cable actuator developed by the United Technologies Corporation (Patents Pending) provides significant work output (greater than 2200 in-lb per flap, through the range of motion) in a compact package and minimizes system complexity. Results of a detailed design study indicate substantial engine performance, weight, and range benefits. The SMA- based actuation system is roughly two times lighter than a conventional mechanical system, with significant aircraft direct operating cost savings (2-3%) and range improvements (5-6%) relative to a fixed-geometry nozzle geared turbofan. A full-scale sector model of this VAN system was built and then tested at the Jet Exit Test Facility at NASA Langley to demonstrate the system's ability to achieve 20% area variation of the nozzle under full scale aerodynamic loads. The actuator exceeded requirements, achieving repeated actuation against full-scale loads representative of typical cruise as well as greater than worst-case (ultimate) aerodynamic conditions. Based on these encouraging results, work is continuing with the goal of a flight test on a C-17 transport aircraft.

General Aerodynamic Characteristics of a Research Model with High Disk Loading Direct Lifting Fan Mounted in Fuselage

NASA Image and Video Library

1960-10-26

3/4 Low front view of fuselage and fan. Showing jet engine hanging below. Lift fan powered by jet exhaust. General Aerodynamic Characteristics of a Research Model with High Disk Loading Direct Lifting Fan Mounted in Fuselage

Supersonic throughflow fans for high-speed aircraft

NASA Technical Reports Server (NTRS)

Ball, Calvin L.; Moore, Royce D.

1990-01-01

A brief overview is provided of past supersonic throughflow fan activities; technology needs are discussed; the design is described of a supersonic throughflow fan stage, a facility inlet, and a downstream diffuser; and the results are presented from the analysis codes used in executing the design. Also presented is a unique 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.

Experimental Investigation on Design Enhancement of Axial Fan Using Fixed Guide Vane

NASA Astrophysics Data System (ADS)

Munisamy, K. M.; Govindasamy, R.; Thangaraju, S. K.

2015-09-01

Airflow passes through the rotating blade in an axial flow fan will experience a helical flow pattern. This swirling effect leads the system to experience swirl energy losses or pressure drop yet reducing the total efficiency of the fan system. A robust tool to encounter this air spin past the blade is by introducing guide vane to the system. Owing to its importance, a new approach in designing outlet guide vane design for a commercial usage 1250mm diameter axial fan with a 30° pitch angle impeller has been introduced in this paper. A single line metal of proper curvature guide vane design technique has been adopted for this study. By choosing fan total efficiency as a target variable to be improved, the total and static pressure on the design point were set to be constraints. Therefore, the guide vane design was done based on the improvement target on the static pressure in system. The research shows that, with the improvement in static pressure by 29.63% through guide vane installation, the total fan efficiency is increased by 5.12%, thus reduces the fan power by 5.32%. Good agreement were found, that when the fan total efficiency increases, the power consumption of the fan is reduced. Therefore, this new approach of guide vane design can be applied to improve axial fan performance.

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.

Design study of an air pump and integral lift engine ALF-504 using the Lycoming 502 core

NASA Technical Reports Server (NTRS)

Rauch, D.

1972-01-01

Design studies were conducted for an integral lift fan engine utilizing the Lycoming 502 fan core with the final MQT power turbine. The fan is designed for a 12.5 bypass ratio and 1.25:1 pressure ratio, and provides supercharging for the core. Maximum sea level static thrust is 8370 pounds with a specific fuel consumption of 0.302 lb/hr-lb. The dry engine weight without starter is 1419 pounds including full-length duct and sound-attenuating rings. The engine envelope including duct treatment but not localized accessory protrusion is 53.25 inches in diameter and 59.2 inches long from exhaust nozzle exit to fan inlet flange. Detailed analyses include fan aerodynamics, fan and reduction gear mechanical design, fan dynamic analysis, engine noise analysis, engine performance, and weight analysis.

Acoustic Power Transmission Through a Ducted Fan

NASA Technical Reports Server (NTRS)

Envia, Ed

2016-01-01

For high-speed ducted fans, when the rotor flowfield is shock-free, the main contribution to the inlet radiated acoustic power comes from the portion of the rotor stator interaction sound field that is transmitted upstream through the rotor. As such, inclusion of the acoustic transmission is an essential ingredient in the prediction of the fan inlet noise when the fan tip relative speed is subsonic. This paper describes a linearized Euler based approach to computing the acoustic transmission of fan tones through the rotor. The approach is embodied in a code called LINFLUX was applied to a candidate subsonic fan called the Advanced Ducted Propulsor (ADP). The results from this study suggest that it is possible to make such prediction with sufficient fidelity to provide an indication of the acoustic transmission trends with the fan tip speed.

Acoustic and aerodynamic performance of a 1.5-pressure-ratio, 1.83-meter (6 ft) diameter fan stage for turbofan engines (QF-2)

NASA Technical Reports Server (NTRS)

Woodward, R. P.; Lucas, J. G.; Balombin, J. R.

1977-01-01

The fan was externally driven by an electric motor. Design features for low-noise generation included the elimination of inlet guide vanes, long axial spacing between the rotor and stator blade rows, and the selection of blade-vane numbers to achieve duct-mode cutoff. The fan QF-2 results were compared with those of another full-scale fan having essentially identical aerodynamic design except for nozzle geometry and the direction of rotation. The fan QF-2 aerodynamic results were also compared with those obtained from a 50.8 cm rotor-tip-diameter model of the reverse rotation fan QF-2 design. Differences in nozzle geometry other than exit area significantly affected the comparison of the results of the full-scale fans.

Noise generated by quiet engine fans. 2: Fan A. [measurement of power spectra and sideline perceived noise levels

NASA Technical Reports Server (NTRS)

Montegani, F. J.; Schaefer, J. W.; Stakolich, E. G.

1974-01-01

A significant effort within the NASA Quiet Engine Program has been devoted to acoustical evaluation at the Lewis Research Center noise test facility of a family of full-scale fans. This report, documents the noise results obtained with fan A - a 1.5-pressure-ratio, 1160-ft/sec-tip-speed fan. The fan is described and some aerodynamic operating data are given. Far-field noise around the fan was measured for a variety of configurations pertaining to acoustical treatment and over a range of operating conditions. Complete results of 1/3-octave band analysis of the data are presented in tabular form. Included also are power spectra and sideline perceived noise levels. Some representative 1/3-octave band data are presented graphically, and sample graphs of continuous narrow-band spectra are also provided.

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.

Vertical/Short Takeoff and Landing Model in the 10- by 10-Foot Supersonic Wind Tunnel

NASA Image and Video Library

1979-05-21

A technician checks a 0.25-scale engine model of a Vought Corporation V-530 engine in the test section of the 10- by 10-Foot Supersonic Wind Tunnel at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Vought created a low-drag tandem-fan Vertical/Short and Takeoff and Landing (V/STOL) engine in the mid-1970s, designated as the V-530. The first fan on the tandem-fan engine was supplied with air through a traditional subsonic inlet, seen on the lower front of the engine. The air was exhausted through the nacelle during normal flight and directed down during takeoffs. The rear fan was supplied by the oval-shaped top inlet during all phases of the flight. The second fan exhausted its air through a rear vectorable nozzle. NASA Lewis and Vought partnered in the late 1970s to collect an array of inlet and nozzle design information on the tandem fan engines for the Navy. Vought created this .25-scale model of the V-530 for extensive testing in Lewis' 10- by 10-foot tunnel. During an early series of tests, the front fan was covered, and a turbofan simulator was used to supply air to the rear fan. The researchers then analyzed the performance of only the front fan inlet. During the final series of tests, the flow from the front fan was used to supply airflow to the rear fan. The researchers studied the inlet's recovery, distortion, and angle-of-attack limits over various flight conditions.

Effect of tip flange on tip leakage flow of small axial flow fans

NASA Astrophysics Data System (ADS)

Zhang, Li; Jin, Yingzi; Jin, Yuzhen

2014-02-01

Aerodynamic performance of an axial flow fan is closely related to its tip clearance leakage flow. In this paper, the hot-wire anemometer is used to measure the three dimensional mean velocity near the blade tips. Moreover, the filtered N-S equations with finite volume method and RNG k-ɛ turbulence model are adopted to carry out the steady simulation calculation of several fans that differ only in tip flange shape and number. The large eddy simulation and the FW-H noise models are adopted to carry out the unsteady numerical calculation and aerodynamic noise prediction. The results of simulation calculation agree roughly with that of tests, which proves the numerical calculation method is feasible.The effects of tip flange shapes and numbers on the blade tip vortex structure and the characteristics are analyzed. The results show that tip flange of the fan has a certain influence on the characteristics of the fan. The maximum efficiencies for the fans with tip flanges are shifted towards partial flow with respect to the design point of the datum fan. Furthermore, the noise characteristics for the fans with tip flanges have become more deteriorated than that for the datum fan. Tip flange contributes to forming tip vortex shedding and the effect of the half-cylinder tip flange on tip vortex shedding is obvious. There is a distinct relationship between the characteristics of the fan and tip vortex shedding. The research results provide the profitable reference for the internal flow mechanism of the performance optimization of small axial flow fans.

30 CFR 57.22203 - Main fan operation (I-C mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main fan operation (I-C mines). 57.22203... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22203 Main fan operation (I-C mines). Main fans shall be operated continuously while ore production is in progress. ...

ENERGY STAR Certified Ventilating Fans

EPA Pesticide Factsheets

Certified models meet all ENERGY STAR requirements as listed in the Version 4.0 ENERGY STAR Program Requirements for Ventilating Fans that are effective as of October 1, 2015. A detailed listing of key efficiency criteria are available at http://www.energystar.gov/index.cfm?c=vent_fans.pr_crit_vent_fans

30 CFR 57.8529 - Auxiliary fan systems

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Auxiliary fan systems 57.8529 Section 57.8529 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Underground Only § 57.8529 Auxiliary fan systems When auxiliary fan systems are used, such systems shall...

ENERGY STAR Certified Ceiling Fans

EPA Pesticide Factsheets

Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Ceiling Fans that are effective as of April 1, 2012. A detailed listing of key efficiency criteria are available at http://www.energystar.gov/index.cfm?c=ceiling_fans.pr_crit_ceiling_fans

Online Fan Fiction and Critical Media Literacy

ERIC Educational Resources Information Center

Black, Rebecca W.

2010-01-01

This article explores English-language-learning (ELL) youths' engagement with popular media through composing and publicly posting stories in an online fan fiction writing space. Fan fiction is a genre that lends itself to critical engagement with media texts as fans repurpose popular media to design their own narratives. Analyses describe how…

78 FR 42758 - 36(b)(1) Arms Sales Notification

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-17

... aircraft, to include: Inlet/Fan Modules, Core Engine Modules, Rear Compressor Drive Turbines, Fan Drive...-PW-229 engines for the Hellenic Air Force F-16 aircraft, to include: Inlet/Fan Modules, Core Engine Modules, Rear Compressor Drive Turbines, Fan Drive Turbine Modules, Augmentor Duct and Nozzle Modules, and...

30 CFR 57.8525 - Main fan maintenance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main fan maintenance. 57.8525 Section 57.8525 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Underground Only § 57.8525 Main fan maintenance. Main fans shall be maintained according to either the...

Alcohol-Related Fan Behavior on College Football Game Day

ERIC Educational Resources Information Center

Glassman, Tavis; Werch, Chudley E.; Jobli, Edessa; Bian, Hui

2007-01-01

High-risk drinking on game day represents a unique public health challenge. Objective: The authors examined the drinking behavior of college football fans and assessed the support for related interventions. Participants: The authors randomly selected 762 football fans, including college students, alumni, and other college football fans, to…

A general representation for axial-flow fans and turbines

NASA Technical Reports Server (NTRS)

Perl, W; Tucker, M

1945-01-01

A general representation of fan and turbine arrangements on a single classification chart is presented that is made possible by a particular definition of the stage of an axial-flow fan or turbine. Several unconventional fan and turbine arrangements are indicated and the applications of these arrangements are discussed.

30 CFR 75.331 - Auxiliary fans and tubing.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... (a) When auxiliary fans and tubing are used for face ventilation, each auxiliary fan shall be— (1... auxiliary fan is stopped— (1) Line brattice or other face ventilation control devices shall be used to maintain ventilation to affected faces; and (2) Electrical equipment in the affected working places shall...

30 CFR 75.331 - Auxiliary fans and tubing.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... (a) When auxiliary fans and tubing are used for face ventilation, each auxiliary fan shall be— (1... auxiliary fan is stopped— (1) Line brattice or other face ventilation control devices shall be used to maintain ventilation to affected faces; and (2) Electrical equipment in the affected working places shall...

30 CFR 75.331 - Auxiliary fans and tubing.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... (a) When auxiliary fans and tubing are used for face ventilation, each auxiliary fan shall be— (1... auxiliary fan is stopped— (1) Line brattice or other face ventilation control devices shall be used to maintain ventilation to affected faces; and (2) Electrical equipment in the affected working places shall...

On orthogonal projectors induced by compact groups and Haar measures

NASA Astrophysics Data System (ADS)

Niezgoda, Marek

2008-02-01

We study the difference of two orthogonal projectors induced by compact groups of linear operators acting on a vector space. An upper bound for the difference is derived using the Haar measures of the groups. A particular attention is paid to finite groups. Some applications are given for complex matrices and unitarily invariant norms. Majorization inequalities of Fan and Hoffmann and of Causey are rediscovered.

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.

Longitudinal aerodynamic characteristics of a low-wing lift-fan transport including hover characteristics in and out of ground effect

NASA Technical Reports Server (NTRS)

Hoad, D. R.; Gentry, G. L., Jr.

1977-01-01

The longitudinal aerodynamic characteristics of a six-fan, tip-driven (remote) lift-fan VTOL transport through transition were determined by an investigation conducted in the Langley V/STOL tunnel. Tests were also made with the large midspan lift-fan pods and lift-cruise fans removed to determine their their influence on the stability and control of the configuration. Data were obtained for a range of model height above ground.

Prop-fan data support study

NASA Technical Reports Server (NTRS)

Baum, J. A.; Dumais, P. J.; Mayo, M. G.; Metzger, F. B.; Shenkman, A. M.; Walker, G. G.

1978-01-01

Updated parametric prop-fan data packages are presented and the rationale used in developing the new prop-fan data is detailed. These data represent Hamilton Standard's projections of prop-fan characteristics for aircraft that are expected to be in-service in the 1985 to 1990 time frame. The basic prop-fan configuration was designed for efficient cruise operation at 0.8 Mach number and 10,668M altitude. The design blade tip speed is 244 mps and the design power loading is 301 KW/M squared.

Evaluation of a ducted-fan power plant designed for high output and good cruise fuel economy

NASA Technical Reports Server (NTRS)

Behun, M; Rom, F E; Hensley, R V

1950-01-01

Theoretical analysis of performance of a ducted-fan power plant designed both for high-output, high-altitude operation at low supersonic Mach numbers and for good fuel economy at lower fight speeds is presented. Performance of ducted fan is compared with performance (with and without tail-pipe burner) of two hypothetical turbojet engines. At maximum power, the ducted fan has propulsive thrust per unit of frontal area between thrusts obtained by turbojet engines with and without tail-pipe burners. At cruise, the ducted fan obtains lowest thrust specific fuel consumption. For equal maximum thrusts, the ducted fan obtains cruising flight duration and range appreciably greater than turbojet engines.

Experimental quiet engine program aerodynamic performance of fan A

NASA Technical Reports Server (NTRS)

Giffin, R. G.; Parker, D. E.; Dunbar, L. W.

1971-01-01

The aerodynamic component test results are presented of fan A, one of two high-bypass-ratio, 1160 feet per second single-stage fans, which was designed and tested as part of the NASA Experimental Quiet Engine Program. This fan was designed to deliver a bypass pressure ratio of 1.50 with an adiabatic efficiency of 86.5% at a total fan flow of 950 lb/sec. It was tested with and without inlet flow distortion. A bypass total-pressure ratio of 1.52 and an adiabatic efficiency of 88.3% at a total fan flow of 962 lb/sec were actually achieved. An operating margin of 12.4% was demonstrated at design speed.

Method for fabricating fan-fold shielded electrical leads

DOEpatents

Rohatgi, R.R.; Cowan, T.E.

1994-12-27

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. 3 figures.

Characteristics of an anechoic chamber for fan noise testing

NASA Technical Reports Server (NTRS)

Wuzyniak, J. A.; Shaw, L. M.; Essary, J. D.

1977-01-01

Acoustical and mechanical design features of NASA Lewis Research Center's engine fan noise facility are described. Acoustic evaluation of the chamber, which is lined with an array of stepped wedges, is described. Results from the evaluation in terms of cut-off frequency and non-anechoic areas near the walls are detailed. Fan models are electrically driven to 20,600 RPM in either the inlet mode or exhaust mode to facilitate study of both fore and aft fan noise. Inlet noise characteristics of the first fan tested are discussed and compared to full-scale levels. Turbulence properties of the inlet flow and acoustic results are compared with and without a turbulence reducing screen over the fan inlet.

Impact resistant boron/aluminum composites for large fan blades

NASA Technical Reports Server (NTRS)

Oller, T. L.; Salemme, C. T.; Bowden, J. H.; Doble, G. S.; Melnyk, P.

1977-01-01

Blade-like specimens were subjected to static ballistic impact testing to determine their relative FOD impact resistance levels. It was determined that a plus or minus 15 deg layup exhibited good impact resistance. The design of a large solid boron/aluminum fan blade was conducted based on the FOD test results. The CF6 fan blade was used as a baseline for these design studies. The solid boron/aluminum fan blade design was used to fabricate two blades. This effort enabled the assessment of the scale up of existing blade manufacturing details for the fabrication of a large B/Al fan blade. Existing CF6 fan blade tooling was modified for use in fabricating these blades.

Reduced Perceived Noise Low Tip Speed Fans as a Result of Abandoning Cutoff Stator Vane Numbers

NASA Technical Reports Server (NTRS)

Dittmar, James

1998-01-01

As fan tip speeds are reduced, broadband noise is becoming more important in the calculation of perceived noise. Past experience indicates that lower vane number stators with either constant chord or constant solidity may be a way to reduce broadband noise caused by the interaction of the rotor wake turbulence with the stators. A baseline fan and a low blade number fan were investigated to determine if a noise reduction was possible. The low vane number fan showed a 2 PndB and a 1.5 PNLT noise reduction. These reductions show that this is a viable technique for reducing the perceived noise of low tip speed fans.

Method for fabricating fan-fold shielded electrical leads

DOEpatents

Rohatgi, Rajeev R.; Cowan, Thomas E.

1994-01-01

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.

Fan-fold shielded electrical leads

DOEpatents

Rohatgi, R.R.; Cowan, T.E.

1996-06-11

Disclosed are 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. 3 figs.

Maja Valley and the Chryse outflow complex sites

NASA Technical Reports Server (NTRS)

Rice, Jim W.

1994-01-01

This candidate landing site is located at 19 deg N, 53.5 deg W near the mouth of a major outflow channel. Maja Valles, and two 'valley network' channel systems, Maumee and Vedra Valles. The following objectives are to be analyzed in this region: (1) origin and paleohydrology of outflow and valley network channels; (2) fan delta complex composition (the deposit located in this area is one of the few identified at the mouth s of any channels on the planet); and (3) analysis of any paleolake sediments (carbonates, evaporites). The primary objectives of the Chryse Outflow Complex region (Ares, Tiu, Mawrth, Simud, and Shalbatana Valles) would be outflow channel dynamics (paleohydrology) of five different channel systems.

Experimental quiet engine program

NASA Technical Reports Server (NTRS)

Cornell, W. G.

1975-01-01

Full-scale low-tip-speed fans, a full-scale high-tip-speed fan, scale model versions of fans, and two full-scale high-bypass-ratio turbofan engines, were designed, fabricated, tested, and evaluated. Turbine noise suppression was investigated. Preliminary design studies of flight propulsion system concepts were used in application studies to determine acoustic-economic tradeoffs. Salient results are as follows: tradeoff evaluation of fan tip speed and blade loading; systematic data on source noise characteristics and suppression effectiveness; documentation of high- and low-fan-speed aerodynamic and acoustic technology; aerodynamic and acoustic evaluation of acoustic treatment configurations, casing tip bleed, serrated and variable pitch rotor blades, leaned outlet guide vanes, slotted tip casings, rotor blade shape modifications, and inlet noise suppression; systematic evaluation of aerodynamic and acoustic effects; flyover noise projections of engine test data; turbine noise suppression technology development; and tradeoff evaluation of preliminary design high-fan-speed and low-fan-speed flight engines.

Results of an Advanced Fan Stage Operating Over a Wide Range of Speed and Bypass Ratio. Part 2; Comparison of CFD and Experimental Results

NASA Technical Reports Server (NTRS)

Celestina, Mark L.; Suder, Kenneth L.; Kulkarni, Sameer

2010-01-01

NASA and GE teamed to design and build a 57 percent engine scaled fan stage for a Mach 4 variable cycle turbofan/ramjet engine for access to space with multipoint operations. This fan stage was tested in NASA's transonic compressor facility. The objectives of this test were 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 wind-milling operation at high Mach flight conditions. This paper will focus on an assessment of APNASA, a multistage turbomachinery analysis code developed by NASA, to predict the fan stage performance and operability over a wide range of speeds (37 to 100 percent) and bypass ratios.

A Fan Design that Meets the NASA Aeronautics Noise Goals

NASA Technical Reports Server (NTRS)

Dittmar, James; Tweedt, Daniel; Jeracki, Robert; Envia, Edmaine; Bartos, Karen; Slater, John

2003-01-01

A fan concept was previously identified that would meet the NASA aeronautics goal of a 20 EPNdB reduction in aircraft noise. This was a 2-stage fan with a pressure ratio of 1.15 and a 460 ft/sec tip speed. The 2 stages were identical so that, with the proper synchrophasing, noise from one stage could be used to cancel noise from the other stage. This paper documents the aerodynamic design of the 2-stage fan concept in a 22-in. diameter size for testing in the NASA Glenn 9- by 15-ft wind tunnel. A set of rotor and stator coordinates are listed in the report. Stress and flutter analyses were done on these blades and showed that the design was structurally viable. A noise prediction code, using the blade coordinates and fan flows, indicated that the 2-stage fan would meet the goal of a 20 dB reduction in fan noise.

30 CFR 57.22209 - Auxiliary fans (I-C mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22209 Auxiliary fans (I-C mines.... Tests for methane shall be made at electric auxiliary fans before they are started. Such fans shall not be operated when air passing over or through them contains 0.5 percent or more methane. ...

Test Operations Procedure (TOP) 06-2-301 Wind Testing

DTIC Science & Technology

2017-06-14

critical to ensure that the test item is exposed to the required wind speeds. This may be an iterative process as the fan blade pitch, fan speed...fan speed is the variable that is adjusted to reach the required velocities. Calibration runs with a range of fan speeds are performed and a

30 CFR 75.311 - Main mine fan operation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main mine fan operation. 75.311 Section 75.311... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.311 Main mine fan operation. (a) Main mine fans shall be continuously operated, except as otherwise approved in the ventilation plan, or when...

75 FR 41102 - Energy Conservation Program: Energy Conservation Standards for Furnace Fans: Reopening of Public...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-15

... Furnace Fans: Reopening of Public Comment Period AGENCY: Office of Energy Efficiency and Renewable Energy... work of residential heating and cooling systems (``furnace fans''). The comment period closed on July 6... information relevant to the furnace fan rulemaking will be accepted until July 27, 2010. ADDRESSES: Interested...

30 CFR 57.22209 - Auxiliary fans (I-C mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22209 Auxiliary fans (I-C mines.... Tests for methane shall be made at electric auxiliary fans before they are started. Such fans shall not be operated when air passing over or through them contains 0.5 percent or more methane. ...

10 CFR 429.33 - Ceiling fan light kits.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Ceiling fan light kits. 429.33 Section 429.33 Energy... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.33 Ceiling fan light kits. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to ceiling fan light kits...

10 CFR 429.33 - Ceiling fan light kits.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Ceiling fan light kits. 429.33 Section 429.33 Energy... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.33 Ceiling fan light kits. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to ceiling fan light kits...

10 CFR 429.33 - Ceiling fan light kits.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Ceiling fan light kits. 429.33 Section 429.33 Energy... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.33 Ceiling fan light kits. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to ceiling fan light kits...

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.

The Aerodynamic Performance of an Over-the-Rotor Liner With Circumferential Grooves on a High Bypass Ratio Turbofan Rotor

NASA Technical Reports Server (NTRS)

Bozak, Richard F.; Hughes, Christopher E.; Buckley, James

2013-01-01

While liners have been utilized throughout turbofan ducts to attenuate fan noise, additional attenuation is obtainable by placing an acoustic liner over-the-rotor. Previous experiments have shown significant fan performance losses when acoustic liners are installed over-the-rotor. The fan blades induce an oscillating flow in the acoustic liners which results in a performance loss near the blade tip. An over-the-rotor liner was designed with circumferential grooves between the fan blade tips and the acoustic liner to reduce the oscillating flow in the acoustic liner. An experiment was conducted in the W-8 Single-Stage Axial Compressor Facility at NASA Glenn Research Center on a 1.5 pressure ratio fan to evaluate the impact of this over-the-rotor treatment design on fan aerodynamic performance. The addition of a circumferentially grooved over-the-rotor design between the fan blades and the acoustic liner reduced the performance loss, in terms of fan adiabatic efficiency, to less than 1 percent which is within the repeatability of this experiment.

The Aerodynamic Performance of an Over-The-Rotor Liner with Circumferential Grooves on a High Bypass Ratio Turbofan Rotor

NASA Technical Reports Server (NTRS)

Bozak, Rick; Hughes, Christopher; Buckley, James

2013-01-01

While liners have been utilized throughout turbofan ducts to attenuate fan noise, additional attenuation is obtainable by placing an acoustic liner over-the-rotor. Previous experiments have shown significant fan performance losses when acoustic liners are installed over-the-rotor. The fan blades induce an oscillating flow in the acoustic liners which results in a performance loss near the blade tip. An over-the-rotor liner was designed with circumferential grooves between the fan blade tips and the acoustic liner to reduce the oscillating flow in the acoustic liner. An experiment was conducted in the W-8 Single-Stage Axial Compressor Facility at NASA Glenn Research Center on a 1.5 pressure ratio fan to evaluate the impact of this over-the-rotor treatment design on fan aerodynamic performance. The addition of a circumferentially grooved over-the-rotor design between the fan blades and the acoustic liner reduced the performance loss, in terms of fan adiabatic efficiency, to less than 1% which is within the repeatability of this experiment.

Numerical Simulation and Experimental Validation of Failure Caused by Vibration of a Fan

NASA Astrophysics Data System (ADS)

Zhou, Qiang; Han, Wu; Feng, Jianmei; Jia, Xiaohan; Peng, Xueyuan

2017-08-01

This paper presents the root cause analysis of an unexpected fracture occurred on the blades of a motor fan used in a natural gas reciprocating compressor unit. A finite element model was established to investigate the natural frequencies and modal shapes of the fan, and a modal test was performed to verify the numerical results. It was indicated that the numerical results agreed well with experimental data. The third order natural frequency was close to the six times excitation frequency, and the corresponding modal shape was the combination of bending and torsional vibration, which consequently contributed to low-order resonance and fracture failure of the fan. The torsional moment obtained by a torsional vibration analysis of the compressor shaft system was exerted on the numerical model of the fan to evaluate the dynamic stress response of the fan. The results showed that the stress concentration regions on the numerical model were consistent with the location of fractures on the fan. Based on the numerical simulation and experimental validation, some recommendations were given to improve the reliability of the motor fan.

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.

An Assessment of NASA Glenn's Aeroacoustic Experimental and Predictive Capabilities for Installed Cooling Fans. Part 1; Aerodynamic Performance

NASA Technical Reports Server (NTRS)

VanZante, Dale E.; Koch, L. Danielle; Wernet, Mark P.; Podboy, Gary G.

2006-01-01

Driven by the need for low production costs, electronics cooling fans have evolved differently than the bladed components of gas turbine engines which incorporate multiple technologies to enhance performance and durability while reducing noise emissions. Drawing upon NASA Glenn's experience in the measurement and prediction of gas turbine engine aeroacoustic performance, tests have been conducted to determine if these tools and techniques can be extended for application to the aerodynamics and acoustics of electronics cooling fans. An automated fan plenum installed in NASA Glenn's Acoustical Testing Laboratory was used to map the overall aerodynamic and acoustic performance of a spaceflight qualified 80 mm diameter axial cooling fan. In order to more accurately identify noise sources, diagnose performance limiting aerodynamic deficiencies, and validate noise prediction codes, additional aerodynamic measurements were recorded for two operating points: free delivery and a mild stall condition. Non-uniformities in the fan s inlet and exhaust regions captured by Particle Image Velocimetry measurements, and rotor blade wakes characterized by hot wire anemometry measurements provide some assessment of the fan aerodynamic performance. The data can be used to identify fan installation/design changes which could enlarge the stable operating region for the fan and improve its aerodynamic performance and reduce noise emissions.

Engaging in distancing tactics among sport fans: effects on self-esteem and emotional responses.

PubMed

Bizman, Aharon; Yinon, Yoel

2002-06-01

The authors examined the effects of distancing tactics on self-esteem and emotions, following a win or loss of one's favorite team. They measured state self-esteem and emotional responses of basketball fans as they exited the sport arena after their team had won or lost an official game. Half of the fans were given the opportunity to increase or decrease their association with the team before the measures of self-esteem and emotions; the remaining fans were given the opportunity after the measures. The fans tended to associate more with the team after team success than after team failure. In addition, self-esteem and positive emotions were higher, and negative emotions lower, when measured after, rather than before, the opportunity to increase or decrease association with the team. Those effects were more pronounced among high-team-identification fans than among low-team-identification fans. The results suggest a distinction between the short- and long-term effects of game outcome on the willingness to associate with one's team. In the short term, willingness to associate with the team may oscillate in accordance with team performance, even among high-team-identification fans; in the long term, only high-team-identification fans may maintain their allegiance to the team.

Factor Associated with Neutral Sphingomyelinase Activity Mediates Navigational Capacity of Leukocytes Responding to Wounds and Infection: Live Imaging Studies in Zebrafish Larvae

PubMed Central

Boecke, Alexandra; Sieger, Dirk; Neacsu, Cristian Dan; Kashkar, Hamid

2012-01-01

Factor associated with neutral sphingomyelinase activity (FAN) is an adaptor protein that specifically binds to the p55 receptor for TNF (TNF-RI). Our previous investigations demonstrated that FAN plays a role in TNF-induced actin reorganization by connecting the plasma membrane with actin cytoskeleton, suggesting that FAN may impact on cellular motility in response to TNF and in the context of immune inflammatory conditions. In this study, we used the translucent zebrafish larvae for in vivo analysis of leukocyte migration after morpholino knockdown of FAN. FAN-deficient zebrafish leukocytes were impaired in their migration toward tail fin wounds, leading to a reduced number of cells reaching the wound. Furthermore, FAN-deficient leukocytes show an impaired response to bacterial infections, suggesting that FAN is generally required for the directed chemotactic response of immune cells independent of the nature of the stimulus. Cell-tracking analysis up to 3 h after injury revealed that the reduced number of leukocytes is not due to a reduction in random motility or speed of movement. Leukocytes from FAN-deficient embryos protrude pseudopodia in all directions instead of having one clear leading edge. Our results suggest that FAN-deficient leukocytes exhibit an impaired navigational capacity, leading to a disrupted chemotactic response. PMID:22802420

Predicted and Measured Modal Sound Power Levels for a Fan Ingesting Distorted Inflow

NASA Technical Reports Server (NTRS)

Koch, L. Danielle

2010-01-01

Refinements have been made to a method for estimating the modal sound power levels of a ducted fan ingesting distorted inflow. By assuming that each propagating circumferential mode consists only of a single radial mode (the one with the highest cut-off ratio), circumferential mode sound power levels can be computed for a variety of inflow distortion patterns and operating speeds. Predictions from the refined theory have been compared to data from an experiment conducted in the Advanced Noise Control Fan at NASA Glenn Research Center. The inflow to the fan was distorted by inserting cylindrical rods radially into the inlet duct. The rods were placed at an axial location one rotor chord length upstream of the fan and arranged in both regular and irregular circumferential patterns. The fan was operated at 2000, 1800, and 1400 rpm. Acoustic pressure levels were measured in the fan inlet and exhaust ducts using the Rotating Rake fan mode measurement system. Far field sound pressure levels were also measured. It is shown that predicted trends in circumferential mode sound power levels closely match the experimental data for all operating speeds and distortion configurations tested. Insight gained through this work is being used to develop more advanced tools for predicting fan inflow distortion tone noise levels.

Decline of the performance of a portable axial-flow fan due to the friction and duct bending loss of a connected flexible duct.

PubMed

Ojima, Jun

2017-03-28

In a job site, a portable fan is often used to ventilate a confined space. When a portable fan is applied to such a space, the actual ventilation flow rate must be accurately estimated in advance because the safety level of contaminant and oxygen concentrations in the space will determine the ventilation requirements. When a portable fan is used with a flexible duct, the actual flow rate of the fan decreases due to the friction and duct bending loss of the duct. Intending to show the decline of a fan performance, the author conducted laboratory experiments and reported the quantitative effect of the friction and duct bending loss of a flexible duct to the flow rate of a portable fan. Four commercial portable fans of different specifications were procured for the experiments, and the decline of the performance of each portable fan due to the friction loss etc. of a connected flexible duct was investigated by measuring actual flow rate. The flow rate showed an obvious decrease from the rated flow rate when a flexible duct was connected. Connection of a straight polyester flexible duct and a straight aluminum flexible duct reduced the flow rates to 81.2 - 52.9% and less than 50%, respectively. The flow rate decreased with an increase of the bend angle of the flexible duct. It is recommended that flow rate check of a portable fan should be diligently carried out in every job site.

V/STOL Tandem Fan transition section model test. [in the Lewis Research Center 10-by-10 foot wind tunnel

NASA Technical Reports Server (NTRS)

Simpkin, W. E.

1982-01-01

An approximately 0.25 scale model of the transition section of a tandem fan variable cycle engine nacelle was tested in the NASA Lewis Research Center 10-by-10 foot wind tunnel. Two 12-inch, tip-turbine driven fans were used to simulate a tandem fan engine. Three testing modes simulated a V/STOL tandem fan airplane. Parallel mode has two separate propulsion streams for maximum low speed performance. A front inlet, fan, and downward vectorable nozzle forms one stream. An auxilliary top inlet provides air to the aft fan - supplying the core engine and aft vectorable nozzle. Front nozzle and top inlet closure, and removal of a blocker door separating the two streams configures the tandem fan for series mode operations as a typical aircraft propulsion system. Transition mode operation is formed by intermediate settings of the front nozzle, blocker door, and top inlet. Emphasis was on the total pressure recovery and flow distortion at the aft fan face. A range of fan flow rates were tested at tunnel airspeeds from 0 to 240 knots, and angles-of-attack from -10 to 40 deg for all three modes. In addition to the model variables for the three modes, model variants of the top inlet were tested in the parallel mode only. These lip variables were: aft lip boundary layer bleed holes, and Three position turning vane. Also a bellmouth extension of the top inlet side lips was tested in parallel mode.

Football fan aggression: the importance of low Basal cortisol and a fair referee.

PubMed

van der Meij, Leander; Klauke, Fabian; Moore, Hannah L; Ludwig, Yannick S; Almela, Mercedes; van Lange, Paul A M

2015-01-01

Fan aggression in football (soccer) is a societal problem that affects many countries worldwide. However, to date, most studies use an epidemiological or survey approach to explain football fan aggression. This study used a controlled laboratory study to advance a model of predictors for fan aggression. To do so, football fans (n = 74) saw a match summary in which their favorite team lost against their most important rival. Next, we measured levels of aggression with the hot sauce paradigm, in which fans were given the opportunity to administer a sample of hot sauce that a rival football supporter had to consume. To investigate if media exposure had the ability to reduce aggression, before the match fans saw a video in which fans of the rival team commented in a neutral, negative, or positive manner on their favorite team. Results showed that the media exposure did not affect aggression. However, participants displayed high levels of aggression and anger after having watched the match. Also, aggression was higher in fans with lower basal cortisol levels, which suggests that part of the aggression displayed was proactive and related to anti-social behavior. Furthermore, aggression was higher when the referee was blamed and aggression was lower when the performance of the participants' favorite team was blamed for the match result. These results indicate that aggression increased when the match result was perceived as unfair. Interventions that aim to reduce football fan aggression should give special attention to the perceived fairness of the match result.

The Connemara Fan: a major glacial grounding line fan west of Ireland

NASA Astrophysics Data System (ADS)

McCarron, Stephen; Praeg, Daniel; Monteys, Xavier; Scott, Gill

2014-05-01

Glacigenic topography on the mid-shelf (~130-350 m water depth) west of Galway, Ireland appears to have the morphological form, internal architecture and sediments associated with a large glacial grounding-line fan. Seismic data collected in 2009 and 2012 (during the GLAMAR and GATEWAYS 1 campaigns) reveal that the broad, arcuate ridges of the 'Olex moraine' form the landward part of a fan system which prograded beyond the mid-shelf break (defining the outer margin of the 'Clare Platform') westwards into the Porcupine Seabight. The topography is comparable to larger shelf-edge trough-mouth fans found further north along the same margin, however no discernible 'trough' has been identified on the Clare Platform. The ridge and fan topographic assemblage is renamed the 'Connemara Fan' in its entirety, based on its genetic relations and geographic location due west of Connemara, western Ireland. A macrofossil recovered from within a debris flow on the outer fan slope comprised of remobilised plumites dates to ~ 20 ka Cal B.P., indicating sediment reworking downslope following deglacial sediment input to at least that time. The Connemara Fan is the most southerly glacigenic fan identified along the north-east Atlantic margin. Its identification also adds to our knowledge of possibly multiple generations of ice sheets feeding onto the Irish shelf from west-central Ireland and the occurrence of ice sheet geometries and dynamics that evacuated ice, melt-water and sediment (ice streams?) westwards across the Clare Platform during past glaciations.

Core-seismic investigation of Surveyor Channel tributaries: Glacial history of the southern Alaskan margin

NASA Astrophysics Data System (ADS)

Somchat, K.; Reece, R.; Gulick, S. P. S.; Asahi, H.; Mix, A. C.

2016-12-01

The low angle subduction and collision of the Yakutat microplate with the North America Plate created, and continues to contribute to the uplift of the Chugach-St. Elias Range. This heavily glaciated, high topography proximal to the shoreline creates a unique source-to-sink system in which glacial sediment is transported and preserved offshore in a deep sea fan without much interruption. The product of this sediment is the Surveyor Fan and Channel system. Four tributary channels form the head of the Surveyor Channel complex and merge into the main channel trunk 200 km from the shelf edge. We integrate drill core and seismic reflection data to study the evolution of these tributaries in order to decipher glacial history of the southern Alaskan margin since the mid-Pleistocene (1.2 Ma). Updated age models from Integrated Ocean Drilling Program Expedition 341 Sites U1417 and U1418 provide a higher resolution chronology of sediment delivery to the Surveyor Fan than previous studies. We regionally extended the mapping of seismic subunits previously identified by Exp. 341 scientists at sites U1417 and U1418 and analyzed regional patterns of sediment deposition. Two-way travel time (isopach) maps of the three subunits show a trend of sediment depocenter shifting to the east since 1.2 Ma, where the Yakutat and Alsek tributaries have increasing sediment flux through time. Changes in sediment flux in each system represent the changes in locations and amplitudes of glacial ice over successive glacial intervals. Additionally, seismic analysis of channel geomorphology shows that each system contains distinct geomorphological evolutions. Since glacial erosion provides the sediment for the fan, the history of glacial ice onshore can be inferred from seismic geomorphology, where changes in glacial ice affect sediment supply and therefore shifts in depocenters and sedimentation pathways. This study shows an interaction between glacial activity onshore and deep sea fan sediment deposition and has implications for how glacial ice at high latitude margins can shape continental margins on a 100 kyr timescale.

Boeing 18-Inch Fan Rig Broadband Noise Test

NASA Technical Reports Server (NTRS)

Ganz, Ulrich W.; Joppa, Paul D.; Patten, Timothy J.; Scharpf, Daniel F.

1998-01-01

The purposes of the subject test were to identify and quantify the mechanisms by which fan broadband noise is produced, and to assess the validity of such theoretical models of those mechanisms as may be available. The test was conducted with the Boeing 18-inch fan rig in the Boeing Low-Speed Aeroacoustic Facility (LSAF). The rig was designed to be particularly clean and geometrically simple to facilitate theoretical modeling and to minimize sources of interfering noise. The inlet is cylindrical and is equipped with a boundary layer suction system. The fan is typical of modern high-by-pass ratio designs but is capable of operating with or without fan exit guide vanes (stators), and there is only a single flow stream. Fan loading and tip clearance are adjustable. Instrumentation included measurements of fan performance, the unsteady flow field incident on the fan and stators, and far-field and in-duct acoustic fields. The acoustic results were manipulated to estimate the noise generated by different sources. Significant fan broadband noise was found to come from the rotor self-noise as measured with clean inflow and no boundary layer. The rotor tip clearance affected rotor self-noise somewhat. The interaction of the rotor with inlet boundary layer turbulence is also a significant source, and is strongly affected by rotor tip clearance. High level noise can be generated by a high-order nonuniform rotating at a fraction of the fan speed, at least when tip clearance and loading are both large. Stator-generated noise is the loudest of the significant sources, by a small margin, at least on this rig. Stator noise is significantly affected by propagation through the fan.

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.

Reconnaissance of alluvial fans as potential sources of gravel aggregate, Santa Cruz River valley, Southeast Arizona

USGS Publications Warehouse

Lindsey, David A.; Melick, Roger

2002-01-01

This investigation was conducted to provide information on the aggregate potential of alluvial fan sediments in the Santa Cruz River valley. Pebble lithology, roundness, and particle size were determined in the field, and structures and textures of alluvial fan sediments were photographed and described. Additional measurements of particle size on digital photographs were made on a computer screen. Digital elevation models were acquired and compiled for viewing the areal extent of selected fans. Alluvial fan gravel in the Santa Cruz River valley reflects the lithology of its source. Gravel derived from granitic and gneissic terrane of the Tortolita, Santa Catalina, and Rincon Mountains weathers to grus and is generally inferior for use as aggregate. Gravel derived from the Tucson, Sierrita, and Tumacacori Mountains is composed mostly of angular particles of volcanic rock, much of it felsic in composition. This angular volcanic gravel should be suitable for use in asphalt but may require treatment for alkali-silica reaction prior to use in concrete. Gravel derived from the Santa Rita Mountains is of mixed plutonic (mostly granitic rocks), volcanic (mostly felsic rocks), and sedimentary (sandstone and carbonate rock) composition. The sedimentary component tends to make gravel derived from the Santa Rita Mountains slightly more rounded than other fan gravel. The coarsest (pebble, cobble, and boulder) gravel is found near the heads (proximal part) of alluvial fans. At the foot (distal part) of alluvial fans, most gravel is pebble-sized and interbedded with sand and silt. Some of the coarsest gravel was observed near the head of the Madera Canyon, Montosa Canyon, and Esperanza Wash fans. The large Cienega Creek fan, located immediately south and southeast of Tucson, consists entirely of distal-fan pebble gravel, sand, and silt.

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.

Low Frequency Noise Contamination in Fan Model Testing

NASA Technical Reports Server (NTRS)

Brown, Clifford A.; Schifer, Nicholas A.

2008-01-01

Aircraft engine noise research and development depends on the ability to study and predict the noise created by each engine component in isolation. The presence of a downstream pylon for a model fan test, however, may result in noise contamination through pylon interactions with the free stream and model exhaust airflows. Additionally, there is the problem of separating the fan and jet noise components generated by the model fan. A methodology was therefore developed to improve the data quality for the 9 15 Low Speed Wind Tunnel (LSWT) at the NASA Glenn Research Center that identifies three noise sources: fan noise, jet noise, and rig noise. The jet noise and rig noise were then measured by mounting a scale model of the 9 15 LSWT model fan installation in a jet rig to simulate everything except the rotating machinery and in duct components of fan noise. The data showed that the spectra measured in the LSWT has a strong rig noise component at frequencies as high as 3 kHz depending on the fan and airflow fan exit velocity. The jet noise was determined to be significantly lower than the rig noise (i.e., noise generated by flow interaction with the downstream support pylon). A mathematical model for the rig noise was then developed using a multi-dimensional least squares fit to the rig noise data. This allows the rig noise to be subtracted or removed, depending on the amplitude of the rig noise relative to the fan noise, at any given frequency, observer angle, or nozzle pressure ratio. The impact of isolating the fan noise with this method on spectra, overall power level (OAPWL), and Effective Perceived Noise Level (EPNL) is studied.

Fan cooling of the resting area in a free stalls dairy barn

NASA Astrophysics Data System (ADS)

Calegari, Ferdinando; Calamari, Luigi; Frazzi, Ermes

2014-08-01

This summer study evaluated the effect of providing additional fans (cooling) in the resting area within a free-stall dairy barn that had fans and sprinklers in the feeding area and paddock availability. Thirty cows were divided into two homogenous groups and kept in two pens: one had the resting area equipped with two fans (FAN) while no fans were added to the other resting area (CON). Microclimatic parameters, rectal temperature (RT), breathing rate (BR), milk yield, and milk pH traits were recorded. Time budgeting and the behaviour of the cows (time spent in the feeding area, standing and lying in other areas) were also recorded using digital video technology. Two slight-to-moderate heat waves were observed. During the hottest period the daily maximum temperature recorded was 33.5 °C and the daily maximum THI was 81.6. During this period, the BR and RT increased only slightly in both groups, with lower BR (n.s.) in FAN compared with CON. Milk yield was better maintained (n.s.) in FAN compared with CON during the hottest period. The FAN cows showed a greater ( P < 0.05) lying time in the free stalls (9.5 and 8.6 h/day in FAN and CON, respectively), whereas CON cows made greater ( P < 0.05) use of the paddock during evening and late evening hours. Consequently, the total daily lying time was 13.5 h/day in both groups. In conclusion, the results suggest that using fans in the resting area improves cow comfort, which increases use of the resting area. The lying time results also suggest that the benefits of providing ventilation in the resting area might be more evident in barns where there is no paddock.

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 coarse particles downfan, a process for which there is currently no mechanistic theory. ?? 2007 Geological Society of America.

The morphometric and stratigraphic framework for estimates of debris flow incidence in the North Cascades foothills, Washington State, USA

NASA Astrophysics Data System (ADS)

Kovanen, Dori J.; Slaymaker, Olav

2008-07-01

Active debris flow fans in the North Cascade Foothills of Washington State constitute a natural hazard of importance to land managers, private property owners and personal security. In the absence of measurements of the sediment fluxes involved in debris flow events, a morphological-evolutionary systems approach, emphasizing stratigraphy, dating, fan morphology and debris flow basin morphometry, was used. Using the stratigraphic framework and 47 radiocarbon dates, frequency of occurrence and relative magnitudes of debris flow events have been estimated for three spatial scales of debris flow systems: the within-fan site scale (84 observations); the fan meso-scale (six observations) and the lumped fan, regional or macro-scale (one fan average and adjacent lake sediments). In order to characterize the morphometric framework, plots of basin area v. fan area, basin area v. fan gradient and the Melton ruggedness number v. fan gradient for the 12 debris flow basins were compared with those documented for semi-arid and paraglacial fans. Basin area to fan area ratios were generally consistent with the estimated level of debris flow activity during the Holocene as reported below. Terrain analysis of three of the most active debris flow basins revealed the variety of modes of slope failure and sediment production in the region. Micro-scale debris flow event systems indicated a range of recurrence intervals for large debris flows from 106-3645 years. The spatial variation of these rates across the fans was generally consistent with previously mapped hazard zones. At the fan meso-scale, the range of recurrence intervals for large debris flows was 273-1566 years and at the regional scale, the estimated recurrence interval of large debris flows was 874 years (with undetermined error bands) during the past 7290 years. Dated lake sediments from the adjacent Lake Whatcom gave recurrence intervals for large sediment producing events ranging from 481-557 years over the past 3900 years and clearly discernible sedimentation events in the lacustrine sediments had a recurrence interval of 67-78 years over that same period.

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 tectonic information in the long-profile, but a mechanistic theory for downfan deposition rate will be needed.

Lacustrine fan delta deposition alongside intrabasinal structural highs in rift basins: an example from the Early Cretaceous Jiuquan Basin, Northwestern China

NASA Astrophysics Data System (ADS)

Zhang, Chengcheng; Muirhead, James D.; Wang, Hua; Chen, Si; Liao, Yuantao; Lu, Zongsheng; Wei, Jun

2018-01-01

Development of fan deltas alongside intrabasinal structural highs has been overlooked compared to those forming on basin margins. However, these fan deltas may provide important clues regarding the tectonic and climatic controls on deposition during rift development. This paper documents fan delta deposition alongside an intrabasinal structural high within the Early Cretaceous Xiagou Formation of the Jiuquan Basin, China, using subsurface geological and geophysical data. Deposits observed in drill core support fan delta deposition occurring almost exclusively through subaerial and subaqueous gravity flows. Subsurface mapping reveals a consistent decrease in the areal extent of fan deltas from lowstand to highstand system tracts, suggesting that deposition alongside the structural high is sensitive to lake-level changes. The temporal and spatial distribution of the fan deltas display retrogradational stacking patterns, where fan deltas exhibit a decreasing lateral extent up-sequence until fan delta deposition terminated and was replaced by deposition of fine-grained lacustrine deposits. The retrogradational stacking patterns observed alongside the intrabasinal structural high are not observed in fan deltas along the basin margin in the lower parts of the Xiagou Formation. Subsidence profiles also show differential subsidence across the basin during the earliest stages of this formation, likely resulting from border fault movements. These data suggest that non-uniform stacking patterns in the lower parts of the Xiagou Formation reflect basin-scale tectonic movements as the dominant control on synrift deposition patterns. However, later stages of Xiagou Formation deposition were characterized by uniform subsidence across the basin, and uniform retrogradational stacking patterns for fan deltas alongside the intrabasinal structural high and border fault. These observations suggest that basin-scale tectonic movements played a relatively limited role in controlling sediment deposition, and imply a potential change to regional-scale processes affecting fan delta deposition during later synrift stages. Climate change is favored here as the region-scale control on the uniform retrogradational fan delta stacking patterns. This assertion is supported by pollen assemblages, isotope signatures, and organic geochemical analyses, which collectively suggest a change from a humid to semi-arid environment during later synrift stages. We suggest that variations in stacking patterns between different fan delta systems can provide insights into the basin- and regional-scale processes that control rift basin deposition.

The Late Cambrian Takaka Terrane, NW Nelson, New Zealand: Accretionary-prism development and arc collision followed by extension and fan-delta deposition at the SE margin of Gondwana

NASA Astrophysics Data System (ADS)

Pound, K. S.

2013-12-01

Re-evaluation of field and lab data indicates that the Cambrian portion of the Takaka Terrane in the Cobb Valley area of NW Nelson, New Zealand preserves the remnants of an accretionary prism complex, across which the Lockett Conglomerate fan-delta was deposited as a consequence of extension. Previous work has recognized that the structurally disrupted lower Takaka Terrane rocks present an amalgam of sedimentary and igneous rocks generated prior to convergence (Junction Formation) or during convergence (Devil River Volcanics Group, Haupiri Group), including arc-related and MORB components. Portions of the sequence have in the past been loosely described as an accretionary prism. Reevaluation of the detailed mapping, sedimentological and provenance studies shows that remnants of a stratigraphic sequence (Junction Formation, Devil River Volcanics Group, Haupiri Group) can be traced through 10 fault-bounded slices, which include a mélange-dominated slice (Balloon Mélange). These slices are the remnants of the accretionary prism; the stratigraphy within each slice generally youngs to the east, and the overall pattern of aging (based on relative age from provenance studies, sparse fossils, stratigraphic relations, and limited isotopic data) indicates that the older rocks generally dominate fault slices to the east, and younger rocks dominate fault slices to the west, delineating imbricate slices within an eastward-dipping subduction zone, in which the faults record a complex history of multi-phase reactivation. The Lockett Conglomerate is a ~500-m thick fan-delta conglomerate that is the preserved within one of the fault slices, where it is stratigraphically and structurally highest unit in the lower Takaka Terrane; it is also present as blocks within the Balloon Melange. The Lockett Conglomerate is marine at its base and transitions upwards to fluvial facies. The Lockett Conglomerate has previously been interpreted to result from erosion consequent on continued convergence, but is reinterpreted here as a ';true' fan-delta deposit, sedimentologically similar to deposits associated with extension. Textural and compositional data for the Lockett Conglomerate indicates rapid supply of new material (including quartzite, granite, gabbro, and amphibolitic metavolcanics). The Lockett Conglomerate is proposed here to record the initiation of extension, during which basement faults in the hinterland exposed previously buried source rocks. This new interpretation of the Lockett Conglomerate places that initiation of extension and subsequent passive margin sedimentation (Mt. Ellis and Mt. Arthur Groups) earlier (late Middle Cambrian) than previous work has suggested (Late Cambrian or Early Ordovician). These new interpretations provide input useful for correlations and interpretations of the complex mosaic that preserves a record of tectonic activity and processes at the Antarctic, Tasmanian and SE Australian portions of the Cambrian Gondwana margin.

Intrinsic controls on the range of volumes, morphologies, and dimensions of submarine lobes

NASA Astrophysics Data System (ADS)

Prélat, A.; Covault, J. A.; Hodgson, D. M.; Fildani, A.; Flint, S. S.

2010-12-01

Submarine lobe dimensions from six different systems are compared: 1) the exhumed Permian Fan 3 lobe complex of the Tanqua Karoo, South Africa; 2) the modern Amazon fan channel-mouth lobe complex, offshore Brazil; 3) a portion of the modern distal Zaïre fan, offshore Angola/Congo; 4) a Pleistocene fan of the Kutai basin, subsurface offshore Indonesia; 5) the modern Golo system, offshore east Corsica, France; and 6) a shallow subsurface lobe complex , offshore Nigeria. These six systems have significantly different source-to-sink configurations (shelf dimension and slope topography), sediment supply characteristics (available grain size range and supply rate), tectonic settings, (palaeo) latitude, and delivery systems. Despite these differences, lobe deposits share similar geometric and dimensional characteristics. Lobes are grouped into two distinct populations of geometries that can be related to basin floor topography. The first population corresponds to areally extensive but thin lobes (average width 14 km × length 35 km × thickness 12 m) that were deposited onto low relief basin floor areas. Examples of such systems include the Tanqua Karoo, the Amazon, and the Zaïre systems. The second population corresponds to areally smaller but thicker lobes (average width 5 km × length 8 km × thickness 30 m) that were deposited into settings with higher amplitude of relief, like in the Corsican trough, the Kutai basin, and offshore Nigeria. The two populations of lobe types, however, share similar volumes (a narrow range around 1 or 2 km 3), which suggests that there is a control to the total volume of sediment that individual lobes can reach before they shift to a new locus of deposition. This indicates that the extrinsic processes control the number of lobes deposited per unit time rather than their dimensions. Two alternative hypotheses are presented to explain the similarities in lobe volumes calculated from the six very different systems. The first states that the wide range of starting flow volume and grain size across all systems enters the basin floor as a narrow range due to slope 'filtering' via more overspill and intra-channel deposition in larger systems. The second hypothesis is a result of the gradual decrease in downstream gradient from the distributive channel base to the lobe top during lobe growth. This is not sustainable as the channel will start to aggrade, and when a steeper lateral gradient is present, an avulsion will occur to an adjacent depositional low, which will be used for flows to fill and build a new lobe. This analysis of submarine lobe volumes indicates that the basin floor topography influences lobe geometry, but the fact that lobe volumes have a narrow range indicates a strong influence of intrinsic processes.

Intrinsic controls on the range of volumes, morphologies, and dimensions of submarine lobes

USGS Publications Warehouse

Prelat, A.; Covault, J.A.; Hodgson, D.M.; Fildani, A.; Flint, S.S.

2010-01-01

Submarine lobe dimensions from six different systems are compared: 1) the exhumed Permian Fan 3 lobe complex of the Tanqua Karoo, South Africa; 2) the modern Amazon fan channel-mouth lobe complex, offshore Brazil; 3) a portion of the modern distal Za??re fan, offshore Angola/Congo; 4) a Pleistocene fan of the Kutai basin, subsurface offshore Indonesia; 5) the modern Golo system, offshore east Corsica, France; and 6) a shallow subsurface lobe complex , offshore Nigeria. These six systems have significantly different source-to-sink configurations (shelf dimension and slope topography), sediment supply characteristics (available grain size range and supply rate), tectonic settings, (palaeo) latitude, and delivery systems. Despite these differences, lobe deposits share similar geometric and dimensional characteristics. Lobes are grouped into two distinct populations of geometries that can be related to basin floor topography. The first population corresponds to areally extensive but thin lobes (average width 14km??length 35km??thickness 12m) that were deposited onto low relief basin floor areas. Examples of such systems include the Tanqua Karoo, the Amazon, and the Za??re systems. The second population corresponds to areally smaller but thicker lobes (average width 5km??length 8km??thickness 30m) that were deposited into settings with higher amplitude of relief, like in the Corsican trough, the Kutai basin, and offshore Nigeria. The two populations of lobe types, however, share similar volumes (a narrow range around 1 or 2km3), which suggests that there is a control to the total volume of sediment that individual lobes can reach before they shift to a new locus of deposition. This indicates that the extrinsic processes control the number of lobes deposited per unit time rather than their dimensions. Two alternative hypotheses are presented to explain the similarities in lobe volumes calculated from the six very different systems. The first states that the wide range of starting flow volume and grain size across all systems enters the basin floor as a narrow range due to slope 'filtering' via more overspill and intra-channel deposition in larger systems. The second hypothesis is a result of the gradual decrease in downstream gradient from the distributive channel base to the lobe top during lobe growth. This is not sustainable as the channel will start to aggrade, and when a steeper lateral gradient is present, an avulsion will occur to an adjacent depositional low, which will be used for flows to fill and build a new lobe. This analysis of submarine lobe volumes indicates that the basin floor topography influences lobe geometry, but the fact that lobe volumes have a narrow range indicates a strong influence of intrinsic processes. ?? 2010 Elsevier B.V.

Discrete-frequency and broadband noise radiation from diesel engine cooling fans

NASA Astrophysics Data System (ADS)

Kim, Geon-Seok

This effort focuses on measuring and predicting the discrete-frequency and broadband noise radiated by diesel engine cooling fans. Unsteady forces developed by the interaction of the fan blade with inlet flow are the dominant source for both discrete-frequency and broadband noise of the subject propeller fan. In many cases, a primary source of discrepancy between fan noise prediction and measurement is due to incomplete description of the fan inflow. Particularly, in such engine cooling systems where space is very limited, it would be very difficult, if not, impossible to measure the fan inflow velocity field using the conventional, stationary hot-wire method. Instead, the fan inflow was measured with two-component x-type hot-film probes attached very close to the leading edge of a rotating blade. One of the advantages of the blade-mounted-probe measurement technique is that it measures velocities relative to the rotating probe, which enables the acquired data to be applied directly in many aerodynamic theories that have been developed for the airfoil fixed-coordinate system. However, the velocity time data measured by this technique contains the spatially non-uniform mean velocity field along with the temporal fluctuations. A phase-locked averaging technique was successfully employed to decompose the velocity data into time-invariant flow distortions and fluctuations due to turbulence. The angles of attack of the fan blades, obtained from inlet flow measurements, indicate that the blades are stalled. The fan's radiated noise was measured without contamination from the engine noise by driving the fan with an electric motor. The motor operated at a constant speed while a pair of speed controllable pulleys controlled the fan speed. Narrowband and 1/3-octave band sound power of the cooling fan was measured by using the comparison method with a reference sound source in a reverberant room. The spatially non-uniform mean velocity field was used in axial-flow fan noise theory to predict the discrete-frequency noise at the blade passing frequency (BPF) and harmonics. The unsteady lift was predicted by considering transverse and longitudinal velocity fluctuations. The influences due to an upstream finger guard were also investigated. The radiated sound power spectra that were measured for the fan are shown to be in excellent agreement with those predicted. The agreement between prediction and measurement is only fair at the fundamental BPF tone. Further experimental investigations revealed that the interaction noise between the fan blades and a shroud surrounding the fan might be the dominant source for the radiation at the first harmonic. The space-time correlation functions of the inflow velocity fluctuations were measured and utilized in stochastic lifting surface theory to calculate the unsteady blade lift and resulting broadband fan noise. The integral length scale of the inlet flow was found to be much smaller than the blade-to-blade separate distance of the fan. Therefore, contributions from blade-to-blade correlations of the various elements on different blades were found to be negligible and hence ignored; only the correlations between the strip elements on a given blade were considered. The cross-correlations measured between elements separated by more than the integral length scale were also found to be negligibly small. The predicted broadband sound power spectra agree well with those measured for frequencies greater than 400 Hz. There are deviations between the predictions and measurements at lower frequencies. These are likely due to fan blade stall, and possibly, anomalies in the noise measurement environment. In order to reduce the sound radiation at the blade rate tones, the baseline fan was replaced with a skewed fan. The backward skew angle of 30° was found to effectively reduce the 2nd and higher harmonics of the blade rate tone. The interaction of the shroud opening and the blade tips dominates the sound level at the fundamental tone. This tone was successfully reduced by incorporating a serrated shroud opening. Overall, a 2.8 dB sound power level reduction was achieved by applying the skewed fan and the serrated shroud opening simultaneously. Almost all blade rate tone levels were reduced without adversely affecting the flow performance of the system.

Star Trek Rerun, Reread, Rewritten: Fan Writing as Textual Poaching.

ERIC Educational Resources Information Center

Jenkins III, Henry

1988-01-01

Discusses women who write fiction and fan literature based on the "Star Trek" universe, outlining how Star Trek fans force the primary text to accommodate alternate interests. Also considers the issue of literary property in light of the moral economy of the fan community that shapes the range of permissible retellings of the program…

44 CFR 65.13 - Mapping and map revisions for areas subject to alluvial fan flooding.

Code of Federal Regulations, 2011 CFR

2011-10-01

... areas subject to alluvial fan flooding. 65.13 Section 65.13 Emergency Management and Assistance FEDERAL... areas subject to alluvial fan flooding. This section describes the procedures to be followed and the... provides protection from the base flood in an area subject to alluvial fan flooding. This information must...

44 CFR 65.13 - Mapping and map revisions for areas subject to alluvial fan flooding.

Code of Federal Regulations, 2014 CFR

2014-10-01

... areas subject to alluvial fan flooding. 65.13 Section 65.13 Emergency Management and Assistance FEDERAL... areas subject to alluvial fan flooding. This section describes the procedures to be followed and the... provides protection from the base flood in an area subject to alluvial fan flooding. This information must...

44 CFR 65.13 - Mapping and map revisions for areas subject to alluvial fan flooding.

Code of Federal Regulations, 2013 CFR

2013-10-01

... areas subject to alluvial fan flooding. 65.13 Section 65.13 Emergency Management and Assistance FEDERAL... areas subject to alluvial fan flooding. This section describes the procedures to be followed and the... provides protection from the base flood in an area subject to alluvial fan flooding. This information must...

44 CFR 65.13 - Mapping and map revisions for areas subject to alluvial fan flooding.

Code of Federal Regulations, 2012 CFR

2012-10-01

... areas subject to alluvial fan flooding. 65.13 Section 65.13 Emergency Management and Assistance FEDERAL... areas subject to alluvial fan flooding. This section describes the procedures to be followed and the... provides protection from the base flood in an area subject to alluvial fan flooding. This information must...

41 CFR 102-74.190 - Are portable heaters, fans and other such devices allowed in Government-controlled facilities?

Code of Federal Regulations, 2010 CFR

2010-07-01

..., fans and other such devices allowed in Government-controlled facilities? 102-74.190 Section 102-74.190... § 102-74.190 Are portable heaters, fans and other such devices allowed in Government-controlled facilities? Federal agencies are prohibited from operating portable heaters, fans, and other such devices in...

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.

Application of a Meso-scale Based Ballistic Fabric Model to the Development of Advanced Lightweight Engine Fan Blade-Out Containment Structure

DTIC Science & Technology

2012-09-01

composed of a basic metallic shell structure with a dry Kevlar wrap around it is considered. The fan blade is made of titanium alloy modeled by a Johnson...material. A multilayered Kevlar woven dry fabric structure is wrapped around the thin aluminum shell to form a soft hybrid fan case. A woven fabric material...debris protection fan case composed of a basic metallic shell structure with a dry Kevlar wrap around it is considered. The fan blade is made of titanium

Noise from turbomachinery.

NASA Technical Reports Server (NTRS)

Feiler, C. E.; Conrad, E. W.

1973-01-01

This paper reviews turbomachinery noise from turbofan engines as typified by fan noise. The mechanisms and theories of fan noise are reviewed and concepts for its reduction, including acoustic suppresion are discussed. Correlations of the overall noise data from several full-scale fans tested at NASA-Lewis Research Center are presented as indicative of the current state-of-the-art. Estimates are presented to show economics versus reduced noise for two quieted experimental engines, one with subsonic and one with supersonic fan tip speed. Finally, some concepts that may have the potential to reduce fan noise are indicated.

VSTOL tilt nacelle aerodynamics and its relation to fan blade stresses

NASA Technical Reports Server (NTRS)

Shaw, R. J.; Williams, R. C.; Koncsek, J. L.

1978-01-01

A scale model of a VSTOL tilt nacelle with a 0.508 m single stage fan was tested in a low speed wind tunnel to ascertain inlet aerodynamic and fan aeromechanical performance over the low speed flight envelope. Fan blade stress maxima occurred at discrete rotational speeds corresponding to integral engine order vibrations of the first flatwise bending mode. Increased fan blade stress levels coincided with internal boundary layer separation but became severe only when the separation location had progressed to the entry lip region of the inlet.

Research on influence factor about the dynamic characteristic of armored vehicle hydraulic-driven fan system

NASA Astrophysics Data System (ADS)

Chao, Zhiqiang; Mao, Feiyue; Liu, Xiangbo; Li, Huaying; Han, Shousong

2017-01-01

In view of the large power of armored vehicle cooling system, the demand for high fan speed control and energy saving, this paper expounds the basic composition and principle of hydraulic-driven fan system and establishes the mathematical model of the system. Through the simulation analysis of different parameters, such as displacement of motor and working volume of fan system, the influences of performance parameters on the dynamic characteristic of hydraulic-driven fan system are obtained, which can provide theoretical guidance for system optimization design.

Advanced turboprop testbed systems study

NASA Technical Reports Server (NTRS)

Goldsmith, I. M.

1982-01-01

The proof of concept, feasibility, and verification of the advanced prop fan and of the integrated advanced prop fan aircraft are established. The use of existing hardware is compatible with having a successfully expedited testbed ready for flight. A prop fan testbed aircraft is definitely feasible and necessary for verification of prop fan/prop fan aircraft integrity. The Allison T701 is most suitable as a propulsor and modification of existing engine and propeller controls are adequate for the testbed. The airframer is considered the logical overall systems integrator of the testbed program.

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.

Experimental quiet engine program aerodynamic performance of Fan B

NASA Technical Reports Server (NTRS)

Giffin, R. G.; Parker, D. E.; Dunbar, L. W.

1972-01-01

This report presents the aerodynamic component test results of Fan B, one of two high-bypass-ratio, 1160 feet per second (353.6 m/sec) single-stage fans, which was designed and tested as part of the NASA Experimental Quiet Engine Program. The fan was designed to deliver a bypass pressure ratio of 1.50 with an adiabatic efficiency of 87.0% at a total fan flow of 950 lb/sec (430.9 kg/sec). It was tested with and without inlet distortion. A bypass total pressure ratio of 1.52 and an adiabatic efficiency of 86.9% at a total fan flow of 966 lb/sec (438.2 kg/sec) were actually achieved. An operating margin of 19.5% was demonstrated at design speed.

Design and Manufacture of Wood Blades for Windtunnel Fans

NASA Technical Reports Server (NTRS)

Richardson, S. E.

1998-01-01

Many windtunnels use wooden fan blades, however, because of their usual long life (often in excess of 50 years) wooden blades typically do not have to be replaced very often; therefore, the expertise for designing and building wooden windtunnel fan blades is being lost. The purpose of this report is to document the design and build process so that when replacement blades are eventually required some of the critical information required is available. Information useful to fan-blade designers, fabricators, inspectors, and windtunnel operations personnel is included. Fixed pitch and variable pitch fans as well as fans which range in size from a few feet in diameter to over 40 ft. in diameter are described. Woods, adhesives, and coverings are discussed.

Hamilton Standard Q-fan demonstrator dynamic pitch change test program, volume 1

NASA Technical Reports Server (NTRS)

Demers, W. J.; Nelson, D. J.; Wainauski, H. S.

1975-01-01

Tests of a full scale variable pitch fan engine to obtain data on the structural characteristics, response times, and fan/core engine compatibility during transient changes in blade angle, fan rpm, and engine power is reported. Steady state reverse thrust tests with a take off nozzle configuration were also conducted. The 1.4 meter diameter, 13 bladed controllable pitch fan was driven by a T55 L 11A engine with power and blade angle coordinated by a digital computer. The tests demonstrated an ability to change from full forward thrust to reverse thrust in less than one (1) second. Reverse thrust was effected through feather and through flat pitch; structural characteristics and engine/fan compatibility were within satisfactory limits.

Chronology of processes in high-gradient channels of medium-high mountains and their influence on the properties of alluvial fans

NASA Astrophysics Data System (ADS)

Šilhán, Karel

2014-02-01

High-gradient channels are the locations of the greatest geomorphological activity in medium-high mountains. The channels' frequency and character influence the contemporary morphology and morphometry of alluvial fans. There is currently no detailed information regarding the frequency of these processes in high-gradient channels and the evolution of alluvial fans in medium-high mountains in Central Europe. This study in the Moravskoslezské Beskydy Mts. analysed 22 alluvial fans (10 debris flow fans and 12 fluvial fans). The processes occurring on the fans were dated using dendrogeomorphological methods. A total of 748 increment cores were taken from 374 trees to reconstruct 153 geomorphological process events (60 debris flow and 93 floods). The frequency of the processes has been considerably increasing in the last four decades, which can be related to extensive tree cutting since the 1970s. Processes in high-gradient channels in the region (affecting the alluvial fans across the mountain range) are predominantly controlled by cyclonal activity during the warm periods of the year. Probable triggers of local events are heavy downpours in the summer. In addition, spring snowmelt has been identified as occasionally important. This study of the relations affecting the type and frequency of the processes and their effect on the properties of alluvial fans led to the creation of a universal framework for the medium-high flysch mountains of Central Europe. The framework particularly reflects the influence of the character of hydrometeorological extremes on the frequency and type of processes and their reflection in the properties of alluvial fans.

Acoustic and aerodynamic performance of a 1.83-meter (6-ft) diameter 1.25-pressure-ratio fan (QF-8)

NASA Technical Reports Server (NTRS)

Woodward, R. P.; Lucas, J. G.

1976-01-01

A 1.25-pressure-ratio 1.83-meter (6-ft) tip diameter experimental fan stage with characteristics suitable for engine application on STOL aircraft was tested for acoustic and aerodynamic performance. The design incorporated proven features for low noise, including absence of inlet guide vanes, low rotor blade tip speed, low aerodynamic blade loading, and long axial spacing between the rotor and stator blade rows. The fan was operated with five exhaust nozzle areas. The stage noise levels generally increased with a decrease in nozzle area. Separation of the acoustic one-third octave results into broadband and pure-tone components showed the broadband noise to be greater than the corresponding pure-tone components. The sideline perceived noise was highest in the rear quadrants. The acoustic results of QF-8 were compared with those of two similar STOL application fans in the test series. The QF-8 had somewhat higher relative noise levels than those of the other two fans. The aerodynamic results of QF-8 and the other two fans were compared with corresponding results from 50.8-cm (20-in.) diam scale models of these fans and design values. Although the results for the full-scale and scale models of the other two fans were in reasonable agreement for each design, the full-scale fan QF-8 results showed poor performance compared with corresponding model results and design expectations. Facility effects of the full-scale fan QF-8 installation were considered in analyzing this discrepancy.

Broadband Fan Noise Prediction System for Turbofan Engines. Volume 2; BFaNS User's Manual and Developer's Guide

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 second 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 step-by-step instructions for installing and running BFaNS. It concludes with technical documentation of the BFaNS computer program.

Broadband Fan Noise Prediction System for Turbofan Engines. Volume 1; Setup_BFaNS User's Manual and Developer's Guide

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 first 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 step-by-step instructions for installing and running Setup_BFaNS. It concludes with technical documentation of the Setup_BFaNS computer program.

Football Fan Aggression: The Importance of Low Basal Cortisol and a Fair Referee

PubMed Central

van der Meij, Leander; Almela, Mercedes; van Lange, Paul A. M.

2015-01-01

Fan aggression in football (soccer) is a societal problem that affects many countries worldwide. However, to date, most studies use an epidemiological or survey approach to explain football fan aggression. This study used a controlled laboratory study to advance a model of predictors for fan aggression. To do so, football fans (n = 74) saw a match summary in which their favorite team lost against their most important rival. Next, we measured levels of aggression with the hot sauce paradigm, in which fans were given the opportunity to administer a sample of hot sauce that a rival football supporter had to consume. To investigate if media exposure had the ability to reduce aggression, before the match fans saw a video in which fans of the rival team commented in a neutral, negative, or positive manner on their favorite team. Results showed that the media exposure did not affect aggression. However, participants displayed high levels of aggression and anger after having watched the match. Also, aggression was higher in fans with lower basal cortisol levels, which suggests that part of the aggression displayed was proactive and related to anti-social behavior. Furthermore, aggression was higher when the referee was blamed and aggression was lower when the performance of the participants’ favorite team was blamed for the match result. These results indicate that aggression increased when the match result was perceived as unfair. Interventions that aim to reduce football fan aggression should give special attention to the perceived fairness of the match result. PMID:25844939

Quiet Clean Short-haul Experimental Engine (QCSEE). Aerodynamic and aeromechanical performance of a 50.8 cm (20 inch) diameter 1.34 PR variable pitch fan with core flow

NASA Technical Reports Server (NTRS)

Giffin, R. G.; Mcfalls, R. A.; Beacher, B. F.

1977-01-01

The fan aerodynamic and aeromechanical performance tests of the quiet clean short haul experimental engine under the wing fan and inlet with a simulated core flow are described. Overall forward mode fan performance is presented at each rotor pitch angle setting with conventional flow pressure ratio efficiency fan maps, distinguishing the performance characteristics of the fan bypass and fan core regions. Effects of off design bypass ratio, hybrid inlet geometry, and tip radial inlet distortion on fan performance are determined. The nonaxisymmetric bypass OGV and pylon configuration is assessed relative to both total pressure loss and induced circumferential flow distortion. Reverse mode performance, obtained by resetting the rotor blades through both the stall pitch and flat pitch directions, is discussed in terms of the conventional flow pressure ratio relationship and its implications upon achievable reverse thrust. Core performance in reverse mode operation is presented in terms of overall recovery levels and radial profiles existing at the simulated core inlet plane. Observations of the starting phenomena associated with the initiation of stable rotor flow during acceleration in the reverse mode are briefly discussed. Aeromechanical response characteristics of the fan blades are presented as a separate appendix, along with a description of the vehicle instrumentation and method of data reduction.

Production of specific IgY antibody to the recombinant FanC protein produced in Escherichia coli.

PubMed

Nasiri, Khadijeh; Zibaee, Saeed; Nassiri, Mohammadreza; Tahmoorespur, Mojtaba; Haghparast, Alireza

2016-08-01

Enterotoxigenic Escherichia coli (ETEC) strains are one of the primary causes of diarrhea in newborn calves and in humans, pigs, and sheep. IgY technology has been identified as a promising alternative to generating a mass amount of specific antibody for use in immunotherapy and immunodiagnostics. The purpose of this study was to produce specific antibody by egg yolk antibody (IgY) to recombinant FanC protein from ETEC. FanC (K99) gene was amplified from ETEC by specific primers and polymerase chain reaction. The gene was cloned and subcloned into pTZ57R/T and pET32a (+) vectors, respectively. Recombinant vector was transferred into E. coli BL21 CodonPlus (DE3). Protein expression was investigated by 1 mM IPTG induction. Hens were immunized by the purified recombinant FanC protein. The activity and specificity of the IgY antibody were detected by dot-blotting, Western blotting, and indirect ELISA. We obtained FanC specific IgYs by immunizing the hens with the recombinant FanC protein. The anti-FanC IgY showed binding specifically to the FanC protein of ETEC. The results emphasize that specific IgY against the recombinant FanC protein could be recommended as a candidate for passive immunization against ETEC infection in animals and humans.

Production of specific IgY antibody to the recombinant FanC protein produced in Escherichia coli

PubMed Central

Nasiri, Khadijeh; Zibaee, Saeed; Nassiri, Mohammadreza; Tahmoorespur, Mojtaba; Haghparast, Alireza

2016-01-01

Objective(s): Enterotoxigenic Escherichia coli (ETEC) strains are one of the primary causes of diarrhea in newborn calves and in humans, pigs, and sheep. IgY technology has been identified as a promising alternative to generating a mass amount of specific antibody for use in immunotherapy and immunodiagnostics. The purpose of this study was to produce specific antibody by egg yolk antibody (IgY) to recombinant FanC protein from ETEC. Materials and Methods: FanC (K99) gene was amplified from ETEC by specific primers and polymerase chain reaction. The gene was cloned and subcloned into pTZ57R/T and pET32a (+) vectors, respectively. Recombinant vector was transferred into E. coli BL21 CodonPlus (DE3). Protein expression was investigated by 1 mM IPTG induction. Hens were immunized by the purified recombinant FanC protein. The activity and specificity of the IgY antibody were detected by dot-blotting, Western blotting, and indirect ELISA. Results: We obtained FanC specific IgYs by immunizing the hens with the recombinant FanC protein. The anti-FanC IgY showed binding specifically to the FanC protein of ETEC. Conclusion: The results emphasize that specific IgY against the recombinant FanC protein could be recommended as a candidate for passive immunization against ETEC infection in animals and humans. PMID:27746871

Two-stage, low noise advanced technology fan. 5: Acoustic final report

NASA Technical Reports Server (NTRS)

Sofrin, T. G.; Riloff, N., Jr.

1975-01-01

The NASA Q2S(quiet two-stage) fan is a 0.836m (32.9 in.) diameter model of the STF 433 engine fan, selected in a 1972 study for an Advanced Technology Transport (ATT) airplane. Noise-control features include: low tip speed, moderate stage pressure rise, large blade-vane spacings, no inlet guide vanes, and optimum blade and vane numbers. Tests were run on the baseline Q2S fan with standard inlet and discharge ducts. Further tests were made of a translating centerbody sonic inlet device and treated discharge ducts. Results were scaled to JT8D and JT3D engine fan size for comparison with current two-stage fans, and were also scaled to STF 433 fan size to compare calculated ATT flyover noise with FAR 36 limits. Baseline Q2S results scaled to JT8D and JT3D engine fan sizes showed substantial noise reductions. Calculated unsuppressed baseline ATT flyovers averaged about 2.5 EPNdB below FAR 36 limits. Using measured sonic inlet results, scaled baseline Q2S fan results, and calculated attenuations for a 1975 technology duct liner, projected flyover noise calculations for the ATT averaged about FAR 36 limits minus 10 EPNdB. Advances in suppression technology required to meet the 1985 goal of FAR 36 limits minus 20 EPNdB are discussed.

Performance and noise of a low pressure ratio variable pitch fan designed for general aviation applications. [Langley 30 x 60 Tunnel

NASA Technical Reports Server (NTRS)

Metzger, F. B.; Menthe, R. W.; Mccolgan, C. J.

1980-01-01

A limited study has been conducted to establish the performance and noise characteristics of a low design tip speed (168 m/s, 550 ft/sec) low pressure ratio (1.04) variable pitch fan which was tested in the Langley 30 X 60 tunnel. This fan was designed for minimum noise when installed in the tail mount location of a twin engine aircraft which normally has both nose and tail mounted propulsors. Measurements showed the fan noise to be very close to predictions made during the design of the fan and extremely low in level (65 dBA at 1000 ft) with no acoustic treatment. This is about 8 dB lower than the unshrouded 2 blade propeller normally used in this installation. On the basis of tests conducted during this program, it appears that this level could be further reduced by 2 dBA if optimized acoustic treatments were installed in the fan duct. Even the best of the shrouded propellers tested previously were 7 dB higher in level than the Q-Fan without acoustic treatment. It was found that the cruise performance of this fan was within 5% of the predicted efficiency of 72%. Evaluation of the performance data indicated that disturbances in the inflow to the fan were the probable cause of the reduced performance.

75 FR 1017 - Airworthiness Directives; General Electric Company (GE) CF34-1A, CF34-3A, and CF34-3B Series...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-08

...) fan blades within compliance times specified in the AD, inspecting the fan blade abradable rub strip on certain engines for wear, inspecting the fan blades on certain engines for cracks, inspecting the.... This ad supersedure requires the same actions but corrects the effectivity for certain fan blades...

75 FR 37453 - Notice of Issuance of Final Determination Concerning Dimmer and Fan Speed Switch Controls

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-29

... Determination Concerning Dimmer and Fan Speed Switch Controls AGENCY: U.S. Customs and Border Protection... country of origin of certain dimmer and fan speed switch controls which may be offered to the United... determination CBP concluded that Mexico is the country of origin of the dimmer and fan speed switch controls for...

Aerodynamic Performance Measurements for a Forward Swept Low Noise Fan

NASA Technical Reports Server (NTRS)

Fite, E. Brian

2006-01-01

One source of noise in high tip speed turbofan engines, caused by shocks, is called multiple pure tone noise (MPT's). A new fan, called the Quiet High Speed Fan (QHSF), showed reduced noise over the part speed operating range, which includes MPT's. The QHSF showed improved performance in most respects relative to a baseline fan; however, a partspeed instability discovered during testing reduced the operating range below acceptable limits. The measured QHSF adiabatic efficiency on the fixed nozzle acoustic operating line was 85.1 percent and the baseline fan 82.9 percent, a 2.2 percent improvement. The operating line pressure rise at design point rotational speed and mass flow was 1.764 and 1.755 for the QHSF and baseline fan, respectively. Weight flow at design point speed was 98.28 lbm/sec for the QHSF and 97.97 lbm/sec for the baseline fan. The operability margin for the QHSF approached 0 percent at the 75 percent speed operating condition. The baseline fan maintained sufficient margin throughout the operating range as expected. Based on the stage aerodynamic measurements, this concept shows promise for improved performance over current technology if the operability limitations can be solved.

Rene 95 brazed joint metallurgical program

NASA Technical Reports Server (NTRS)

Gay, C.; Givens, J.; Mastrorroco, S.; Sterman, A.

1972-01-01

This metallurgical program was specifically conducted for the establishment of material properties required for the design of the LF460 fan. The LF460 lift fan is an advanced 18:1 high thrust to weight single stage design. It has a turbine attached to the outer flowpath of the fan blade tip which minimizes the axial depth of the fan. Advanced lightweight attachment designs are employed in this concept to achieve minimum mass polar moments of inertia which are required for good aircraft flight response control. The design features which are unique to this advanced LF460 lift fan are the 0.010 inch thin Udimet 700 alloy integral tip turbine design, minimum weight braze attachment of the turbine to the fan blade, and the high strength and elevated temperature capability of the Rene'95 alloy for the fan blade. The data presented in this report show that the LF460 fan rotor design is feasible and that the design stresses and margins of safety were more than adequate. Prior to any production application, however, additional stress rupture/shear lap joints should be run in order to establish a firm 1200 F stress rupture curve for the CM50 braze metal.

Reactive control of subsonic axial fan noise in a duct.

PubMed

Liu, Y; Choy, Y S; Huang, L; Cheng, L

2014-10-01

Suppressing the ducted fan noise at low frequencies without varying the flow capacity is still a technical challenge. This study examines a conceived device consisting of two tensioned membranes backed with cavities housing the axial fan for suppression of the sound radiation from the axial fan directly. The noise suppression is achieved by destructive interference between the sound fields from the axial fan of a dipole nature and sound radiation from the membrane via vibroacoustics coupling. A two-dimensional model with the flow effect is presented which allows the performance of the device to be explored analytically. The air flow influences the symmetrical behavior and excites the odd in vacuo mode response of the membrane due to kinematic coupling. Such an asymmetrical effect can be compromised with off-center alignment of the axial fan. Tension plays an important role to sustain the performance to revoke the deformation of the membrane during the axial fan operation. With the design of four appropriately tensioned membranes covered by a cylindrical cavity, the first and second blade passage frequencies of the axial fan can be reduced by at least 20 dB. The satisfactory agreement between experiment and theory demonstrates that its feasibility is practical.

An Experimental Study of Fan Inflow Distortion Tone Noise

NASA Technical Reports Server (NTRS)

Koch, L. Danielle

2010-01-01

The tone noise generated when a fan ingests circumferentially distorted flow was studied by an experiment conducted with the Advanced Noise Control Fan at the NASA Glenn Research Center. The inflow was distorted by inserting cylindrical rods radially into the duct. The rods were arranged in circumferentially irregular patterns in three of the five configurations tested. Rods were held in place using a mounting ring with 30 equally spaced holes placed at an axial location one rotor chordlength upstream of the fan. Acoustic pressure was measured in the inlet and exhaust duct of the fan using the Rotating Rake fan tone measurement system. Sound power levels, calculated from the measured data, were plotted as a function of circumferential mode. An analytic description of the unsteady pressure distribution at the interaction plane between the stationary rods and the fan rotor is presented in a form suitable for representing the circumferentially irregularly placed rods. Terms in the analytical description for sound power were proven to be useful in determining the dominant circumferential modes measured in the experiment and the differences in mode power level between the configurations tested. Insight gained through this work will be useful in the development of tools to compute fan inflow distortion tone noise.

Understanding Himalayan erosion and the significance of the Nicobar Fan

NASA Astrophysics Data System (ADS)

McNeill, Lisa C.; Dugan, Brandon; Backman, Jan; Pickering, Kevin T.; Pouderoux, Hugo F. A.; Henstock, Timothy J.; Petronotis, Katerina E.; Carter, Andrew; Chemale, Farid; Milliken, Kitty L.; Kutterolf, Steffen; Mukoyoshi, Hideki; Chen, Wenhuang; Kachovich, Sarah; Mitchison, Freya L.; Bourlange, Sylvain; Colson, Tobias A.; Frederik, Marina C. G.; Guèrin, Gilles; Hamahashi, Mari; House, Brian M.; Hüpers, Andre; Jeppson, Tamara N.; Kenigsberg, Abby R.; Kuranaga, Mebae; Nair, Nisha; Owari, Satoko; Shan, Yehua; Song, Insun; Torres, Marta E.; Vannucchi, Paola; Vrolijk, Peter J.; Yang, Tao; Zhao, Xixi; Thomas, Ellen

2017-10-01

A holistic view of the Bengal-Nicobar Fan system requires sampling the full sedimentary section of the Nicobar Fan, which was achieved for the first time by International Ocean Discovery Program (IODP) Expedition 362 west of North Sumatra. We identified a distinct rise in sediment accumulation rate (SAR) beginning ∼9.5 Ma and reaching 250-350 m/Myr in the 9.5-2 Ma interval, which equal or far exceed rates on the Bengal Fan at similar latitudes. This marked rise in SAR and a constant Himalayan-derived provenance necessitates a major restructuring of sediment routing in the Bengal-Nicobar submarine fan. This coincides with the inversion of the Eastern Himalayan Shillong Plateau and encroachment of the west-propagating Indo-Burmese wedge, which reduced continental accommodation space and increased sediment supply directly to the fan. Our results challenge a commonly held view that changes in sediment flux seen in the Bengal-Nicobar submarine fan were caused by discrete tectonic or climatic events acting on the Himalayan-Tibetan Plateau. Instead, an interplay of tectonic and climatic processes caused the fan system to develop by punctuated changes rather than gradual progradation.

Use of Pressure Sensitive Paint for Diagnostics in Turbomachinery Flows With Shocks

NASA Technical Reports Server (NTRS)

Lepicovsky, Jan; Bencic, Timothy J.

2001-01-01

The technology of pressure sensitive paint (PSP) is well established in external aerodynamics. In internal flows in narrow channels and in turbomachinery cascades, however, there are still unresolved problems. In particular, the internal flows with complex shock structures inside highly curved channels present a challenge. It is not always easy and straightforward to distinguish between true signals and "ghost" images due to multiple internal reflections in narrow channels. To address some of the problems, investigations were first carried out in a narrow supersonic channel of Mach number 2.5. A single wedge or a combination of two wedges were used to generate a complex shock wave structure in the flow. The experience gained in a small supersonic channel was used for surface pressure measurements on the stator vane of a supersonic throughflow fan. The experimental results for several fan operating conditions are shown in a concise form, including performance map points, midspan static tap pressure distributions, and vane suction side pressure fields. Finally, the PSP technique was used in the NASA transonic flutter cascade to compliment flow visualization data and to acquire backwall pressure fields to assess the cascade flow periodicity. A summary of shortcomings of the pressure sensitive paint technology for internal flow application and lessons learned are presented in the conclusion of the paper.

Facies mosaic in a fiord: Carboniferous-Permian Talchir Formation, India

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

Bose, P.K.; Mukhopadhyay, G.; Bhattacharya, H.N.

1988-01-01

Facies analysis of the basal 37m of the Carboniferous-Permian Talchir Formation is a glacier-fed bedrock trough in Dudhi nala, Bihar, India, provides insight into the pattern of sedimentation of course gravels in a fiord. Rapid transitions between 11 recognized facies, together with their complex organization, random variability in bed thickness, and differences in clast, shape, size, and composition indicate coalescence of fans developed from numerous point sources bordering the elongated trough. Converging slide masses and lodgment tillites on the slopes flanking the trough give way to sediment gravity flow deposits composed of an array of conglomerates (matrix and clast supportedmore » with normal, inverse of absence of grading), attendant turbidite sands, and prodelta mud. The rheology of the in-trough flows ranged from plastic laminar to fluidal turbulent in response to flow from slope to floor of the trough. Rapid calving of icebergs during the onset of deglaciation established a wave regime at the mouth of the trough and deposited cross-stratified sandstone replete with dripstones. The impact of large dripstones landing triggered turbidity currents. Continued rise in water level led to eventual preservation of the fan complex under onlapping wave-built shoal facies that grade into a sequence of upward-thinning hummocky cross-stratified sandstone beds virtually devoid of dripstones.« less

Use of pressure-sensitive paint for diagnostics in turbomachinery flows with shocks

NASA Astrophysics Data System (ADS)

Lepicovsky, J.; Bencic, T. J.

2002-07-01

The technology of pressure-sensitive paint (PSP) is well established in external aerodynamics. In internal flows in narrow channels and in turbomachinery cascades, however, there are still unresolved problems. In particular, the internal flows with complex shock structures inside highly curved channels present a challenge. It is not always easy and straightforward to distinguish between true signals and 'ghost' images due to multiple internal reflections in narrow channels. To address some of the problems, investigations were first carried out in a narrow supersonic channel of Mach number 2.5. A single wedge or a combination of two wedges was used to generate a complex shock wave structure in the flow. The experience gained in a small supersonic channel was used for surface pressure measurements on the stator vane of a supersonic throughflow fan. The experimental results for several fan operating conditions are shown in a concise form, including performance map test points, midspan static tap pressure distributions, and vane suction side pressure fields. Finally, the PSP technique was used in the NASA transonic flutter cascade to compliment flow visualization data and to acquire backwall pressure fields to assess the cascade flow periodicity. Lessons learned from this investigation and shortcomings of the PSP technology for internal flow application are presented in the conclusion of the paper.

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.

An Assessment of NASA Glenn's Aeroacoustic Experimental and Predictive Capabilities for Installed Cooling Fans

NASA Technical Reports Server (NTRS)

Koch, L. Danielle; VanZante, Dale E.; Wernet, Mark P.; Podboy, Gary G.

2006-01-01

Quiet, high performance electronics cooling fans are needed for both commercial applications and future manned space exploration missions. Researchers at NASA Glenn focusing on aircraft engine noise, have long been familiar with the challenge of reducing fan noise without sacrificing aerodynamic performance. Is it possible to capitalize on the lessons-learned in aircraft engine noise reduction to identify inexpensive ways to improve the aerodynamic and acoustic performance of electronics cooling fans? Recent tests at NASA Glenn have begun to look for answers to this question. The overall aerodynamic and acoustic performance of a commercially available, spaceflight qualified 80 mm diameter axial flow fan has been measured using an automated plenum in accordance with ISO 10302 in the hemi-anechoic chamber of NASA Glenn s Acoustical Testing Laboratory. These measurements are complemented by detailed aerodynamic measurements of the inlet, exhaust, and rotor wake regions of the fan using Particle Image Velocimetry and hot-wire probes. A study of preliminary results yielded recommendations for system designers, fan manufacturers, and researchers.

Experimental and analytical dynamic flow characteristics of an axial-flow fan from an air cushion landing system model

NASA Technical Reports Server (NTRS)

Thompson, W. C.; Boghani, A. B.; Leland, T. J. W.

1977-01-01

An investigation was conducted to compare the steady-state and dynamic flow characteristics of an axial-flow fan which had been used previously as the air supply fan for some model air cushion landing system studies. Steady-state flow characteristics were determined in the standard manner by using differential orifice pressures for the flow regime from free flow to zero flow. In this same regime, a correlative technique was established so that fan inlet and outlet pressures could be used to measure dynamic flow as created by a rotating damper. Dynamic tests at damper frequencies up to 5 Hz showed very different flow characteristics when compared with steady-state flow, particularly with respect to peak pressures and the pressure-flow relationship at fan stall and unstall. A generalized, rational mathematical fan model was developed based on physical fan parameters and a steady-state flow characteristic. The model showed good correlation with experimental tests at damper frequencies up to 5 Hz.

THz Beam Shaper Realizing Fan-Out Patterns

NASA Astrophysics Data System (ADS)

Liebert, K.; Rachon, M.; Siemion, A.; Suszek, J.; But, D.; Knap, W.; Sypek, M.

2017-08-01

Fan-out elements create an array of beams radiating at particular angles along the propagation axis. Therefore, they are able to form a matrix of equidistant spots in the far-field diffraction region. In this work, we report on the first fan-out structures designed for the THz range of radiation. Two types of light-dividing fan-out structures are demonstrated: (i) the 3×1 matrix fan-out structure based on the optimized binary phase grating and (ii) the 3×3 fan-out structure designed on the basis of the well-known Dammann grating. The structures were generated numerically and manufactured using the 3D printing technique with polyamide PA12. To obtain equal powers and symmetry of diffracted beams, the computer-aided optimization algorithm was used. Diffractive optical elements designed for 140 and 282 GHz were evaluated experimentally at both these frequencies using illumination with the wavefront coming from the point-like source. Described fan-out elements formed uniform intensity and equidistant energy distribution in agreement with the numerical simulations.

Wind tunnel and ground static investigation of a large scale model of a lift/cruise fan V/STOL aircraft

NASA Technical Reports Server (NTRS)

1976-01-01

An investigation was conducted in a 40 foot by 80 foot wind tunnel to determine the aerodynamic/propulsion characteristics of a large scale powered model of a lift/cruise fan V/STOL aircraft. The model was equipped with three 36 inch diameter turbotip X376B fans powered by three T58 gas generators. The lift fan was located forward of the cockpit area and the two lift/cruise fans were located on top of the wing adjacent to the fuselage. The three fans with associated thrust vectoring systems were used to provide vertical, and short, takeoff and landing capability. For conventional cruise mode operation, only the lift/cruise fans were utilized. The data that were obtained include lift, drag, longitudinal and lateral-directional stability characteristics, and control effectiveness. Data were obtained up to speeds of 120 knots at one model height of 20 feet for the conventional aerodynamic lift configuration and at several thrust vector angles for the powered lift configuration.

Flow control of a centrifugal fan in a commercial air conditioner

NASA Astrophysics Data System (ADS)

Kim, Jiyu; Bang, Kyeongtae; Choi, Haecheon; Seo, Eung Ryeol; Kang, Yonghun

2015-11-01

Air-conditioning fans require a low noise level to provide user comfort and quietness. The aerodynamic noise sources are generated by highly unsteady, turbulent structures near the fan blade. In this study, we investigate the flow characteristics of a centrifugal fan in an air-conditioner indoor unit and suggest control ideas to develop a low noise fan. The experiment is conducted at the operation condition where the Reynolds number is 163000 based on the blade tip velocity and chord length. Intermittent separation occurs at the blade leading edge and thus flow significantly fluctuates there, whereas vortex shedding occurs at the blade trailing edge. Furthermore, the discharge flow observed in the axial plane near the shroud shows low-frequency intermittent behaviors, resulting in high Reynolds stresses. To control these flow structures, we modify the shapes of the blade leading edge and shroud of the centrifugal fan and obtain noise reduction. The flow characteristics of the base and modified fans will be discussed. Supported by 0420-20130051.

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.

Predicting the Inflow Distortion Tone Noise of the NASA Glenn Advanced Noise Control Fan with a Combined Quadrupole-Dipole Model

NASA Technical Reports Server (NTRS)

Koch, L. Danielle

2012-01-01

A combined quadrupole-dipole model of fan inflow distortion tone noise has been extended to calculate tone sound power levels generated by obstructions arranged in circumferentially asymmetric locations upstream of a rotor. Trends in calculated sound power level agreed well with measurements from tests conducted in 2007 in the NASA Glenn Advanced Noise Control Fan. Calculated values of sound power levels radiated upstream were demonstrated to be sensitive to the accuracy of the modeled wakes from the cylindrical rods that were placed upstream of the fan to distort the inflow. Results indicate a continued need to obtain accurate aerodynamic predictions and measurements at the fan inlet plane as engineers work towards developing fan inflow distortion tone noise prediction tools.

Variable scale channel avulsion history using fan architecture and stratigraphy, and sediment provenance of Sutlej-Yamuna fans in northwest Gangetic plains during Late Quaternary

NASA Astrophysics Data System (ADS)

Singh, Ajit; Gupta, Sanjeev; Sinha, Rajiv; Densmore, Alexander; Buylaert, Jan-Pieter; Carter, Andrew; Van-Dijk, Wout M.; Joshi, Suneel; Nayak, Nibedita; Mason, Philippa J.; Kumar, Dewashish; Mondal, Setbandhu; Murray, Andrew; Rai, Shiv P.; Shekhar, Shashank

2016-04-01

Channel avulsion during fan development controls distribution and deposition of channel sandbodies and hence alluvial architecture of a fan system. Variable scale spatio-temporal information of fluvial responses to past climate changes is stored in these channel sandbodies. Further these channel sandbodies form fluvial aquifers in alluvial fans and therefore understanding of alluvial architecture and stratigraphy of a fan is crucial for development of groundwater management strategies. In this study we used multiple approaches to map subsurface fluvial aquifer architecture and alluvial stratigraphy, and to estimate sediment provenance using U-Pb dating of detrital zircon grains of Sutlej-Yamuna fan system in northwest India. Satellite imagery based geomorphic mapping shows two large fan system with interfan area. The fan surfaces show presence of major and minor paleochannels. 2D resistivity tomography along several transects across fan surfaces shows distinct layers with contrasting resistivity values. These geo-electric facies corresponds to presence of channel sandbodies beneath surface signature of paleochannels and finer floodplain deposits useful to demarcate lateral extent of subsurface channel sandbodies. A more detailed subsurface stratigraphy using ~50m deep sediment cores and their luminescence ages from across fan surface shows presence of multi-storey sandbodies (MSB) separated by floodplain fines. Within the MSB, individual channel deposits are identified by presence of channel scour surfaces located at coarse sand overlying fine sand layer. Depositional ages of MSB's ranges from ~81 ka (late MIS5) to ~15 ka (MIS2) with major depositional break during MIS3 in parts of the fans. Sediment aggradation rate varies laterally across fan surface as well as vertically down the depth with an average rate of 0.54 mm/year. Fluvial channel persistence for studied time interval (about last 81 ka BP) shows major depositional breaks (and possible incision) at ~41 ka (mid MIS3) and ~31 ka (late MIS3). U-Pb age patterns of detrital zircon grains from cores located at paleochannels on the fan system show prominent age peaks at ~480 Ma and ~1800 Ma that respectively corresponds to modern Sutlej and Yamuna rivers. Luminescence ages of these samples suggest that major channel activity of Sutlej river at its fan system ceased around ~15 ka (post last-glacial maxima) and thereafter it avulsed to its modern course. Our surface study results clearly show that alluvial fan system have well developed longitudinal channel sandbodies that may or may not have surface expression in the form of paleochannel and/or longitudinal ridges. However our geophysical studies show that such channel sandbodies can be delineated in shallow surface on the basis of characteristic resistivity values. The subsurface stratigraphy results show development of MSB possibly due to series of small scale (intravalley) avulsion punctuated by large scale (intervalley) avulsion across the fan surface. Our provenance studies clearly identifies two major large scale channel avulsions of Sutlej and Yamuna rivers. Our study has importance for groundwater management policies in this water-stressed agricultural hotspot of India. Thus, understanding the variability in sand body stratigraphy, channel avulsion history, and aggradation rates is important for understanding aquifer geometry of alluvial fan system.

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.

A measuring stand for a ducted fan aircraft propulsion unit

NASA Astrophysics Data System (ADS)

Hlaváček, David

2014-03-01

The UL-39 ultra-light aircraft which is being developed by the Department of Aerospace Engineering, Faculty of Mechanical Engineering, Czech Technical University in Prague, is equipped with an unconventional ducted fan propulsion unit. The unit consists of an axial fan driven by a piston engine and placed inside a duct ended with a nozzle. This article describes the arrangement of a modernised measuring stand for this highly specific propulsion unit which will be able to measure the fan pressure ratio and velocity field in front of and behind the fan and its characteristic curve.

Fluctuating pressures on fan blades of a turbofan engine: Static and wind-tunnel investigations

NASA Technical Reports Server (NTRS)

Schoenster, J. A.

1982-01-01

To investigate the fan noise generated from turbofan engines, miniature pressure transducers were used to measure the fluctuating pressure on the fan blades of a JT15D engine. Tests were conducted with the engine operating on an outdoor test stand and in a wind tunnel. It was found that a potential flow interaction between the fan blades and six, large support struts in the bypass duct is a dominant noise source in the JT15D engine. Effects of varying fan speed and the forward speed on the blade pressure are also presented.

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

NASA Technical Reports Server (NTRS)

Miller, Christopher J. (Technical Monitor); Weir, Donald

2003-01-01

The Quiet High-Speed Fan program is a cooperative effort between Honeywell Engines & Systems (formerly AlliedSignal Engines & Systems) and the NASA Glenn Research Center. Engines & Systems has designed an advanced high-speed fan that will be tested on the Ultra High Bypass Propulsion Simulator in the NASA Glenn 9 x 15 foot wind tunnel, currently scheduled for the second quarter of 2000. An Engines & Systems modern fan design will be used as a baseline. A nacelle model is provided that is characteristic of a typical, modern regional aircraft nacelle and meets all of the program test objectives.

Evaluation of the Tone Fan Noise Design/Prediction System (TFaNS) at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Koch, L. Danielle

1999-01-01

Version 1.4 of TFaNS, the Tone Fan Noise Design/Prediction System. has recently been evaluated at the NASA Glenn Research Center. Data from tests of the Allison Ultra High Bypass Fan (UHBF) were used to compare to predicted farfield directivities for the radial stator configuration. There was good agreement between measured and predicted directivities at low fan speeds when rotor effects were neglected in the TFaNS calculations. At higher fan speeds, TFaNS is shown to be useful in predicting overall trends rather than absolute sound pressure levels.

Shock Characteristics Measured Upstream of Both a Forward-Swept and an Aft-Swept Fan

NASA Technical Reports Server (NTRS)

Podboy, Gary G.; Krupar, Martin J.; Sutliff, Daniel L.; Horvath, Csaba

2007-01-01

Three different types of diagnostic data-blade surface flow visualization, shroud unsteady pressure, and laser Doppler velocimeter (LDV)--were obtained on two fans, one forward-swept and one aft-swept, in order to learn more about the shocks which propagate upstream of these rotors when they are operated at transonic tip speeds. Flow visualization data are presented for the forward-swept fan operating at 13831 rpm(sub c), and for the aft-swept fan operating at 12500 and 13831 rpm(sub c) (corresponding to tip rotational Mach numbers of 1.07 and 1.19, respectively). The flow visualization data identify where the shocks occur on the suction side of the rotor blades. These data show that at the takeoff speed, 13831 rpm(sub c), the shocks occurring in the tip region of the forward-swept fan are further downstream in the blade passage than with the aft-swept fan. Shroud unsteady pressure measurements were acquired using a linear array of 15 equally-spaced pressure transducers extending from two tip axial chords upstream to 0.8 tip axial chords downstream of the static position of the tip leading edge of each rotor. Such data are presented for each fan operating at one subsonic and five transonic tip speeds. The unsteady pressure data show relatively strong detached shocks propagating upstream of the aft-swept rotor at the three lowest transonic tip speeds, and weak, oblique pressure disturbances attached to the tip of the aft-swept fan at the two highest transonic tip speeds. The unsteady pressure measurements made with the forward-swept fan do not show strong shocks propagating upstream of that rotor at any of the tested speeds. A comparison of the forward-swept and aft-swept shroud unsteady pressure measurements indicates that at any given transonic speed the pressure disturbance just upstream of the tip of the forward-swept fan is much weaker than that of the aft-swept fan. The LDV data suggest that at 12500 and 13831 rpm(sub c), the forward-swept fan swallowed the passage shocks occurring in the tip region of the blades, whereas the aft-swept fan did not. Due to this difference, the flows just upstream of the two fans were found to be quite different at both of these transonic speeds. Nevertheless, despite distinct differences just upstream of the two rotors, the two fan flows were much more alike about one axial blade chord further upstream. As a result, the LDV data suggest that it is unwise to attempt to determine the effect that the shocks have on far field noise by focusing only on measurements (or CFD predictions) made very near the rotor. Instead, these data suggest that it is important to track the shocks throughout the inlet.

Controls on morphometry and morphology of alluvial and colluvial fans in the high-Arctic setting, Petuniabukta, Svalbard.

NASA Astrophysics Data System (ADS)

Tomczyk, Aleksandra; Ewertowski, Marek

2016-04-01

The Petuniabukta (78o42' N, 16o32') is a bay in the northern part of Billefjorden in the central part of Spitsbergen Island, Svalbard. The bay is surrounded by six major, partly glaciated valleys. A numerous alluvial and colluvial fans have developed within valleys as well as along the fiord margins. Distribution and characterization of morphometric parameters of fans were investigated using time-series of orthophotos and digital elevation models (generated based on 1961, 1990, 2009 aerial photographs) and high resolution satellite imagery from 2013. In addition, a very detailed DEM and orthophoto (5 cm resolution) have been produced from unmanned aerial vehicle (UAV) imagery from 2014 and 2015, covering three fans characterised by different types of surface morphology. A 1:40,000 map showing the distribution of almost 300 alluvial and colluvial fans (ranging in area from 325 km2 to 451 275 km2), together with time-series of 1:5,000 geomorphological maps of sample fans enabled an assessment of the spatial and temporal evolution of processes responsible for delivery and erosion of sediments from the fans. The relationship between terrain parameters (e.g. slope, exposition) as well as geology was also investigated. Many of the studied alluvial fans were at least partly coupled and sediments were transferred from the upstream zone to the downstream zone, either due to debris-flow or channelized stream flow. In other cases, coarse sediments were stored within fans, and fines were transported downstream by sheet flows or sub-surface flows. In most of smaller colluvial fans and debris cones, sediments were delivered by mass movement processes (mainly rockfalls and snowfalls) and did not reach lower margin of landforms. Analysis of historical aerial photographs indicated recent increase in the activity of debris-flow modification of surface morphology of fans. Fans located outside limits of the Little Ice Age (LIA) glaciation are dominated by the secondary processes, which do not cause significant aggradation, but can substantially modified surface morphology. In contrary, surface morphology of fans located inside the limits of the LIA glaciation and along contemporary glaciers is dominated by the primary processes of deposition. The research was founded by the Polish National Science Centre.

76 FR 64293 - Airworthiness Directives; CFM International, S. A. Model CFM56-5B Series Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-18

... serial number (S/N) fan blades, part number (P/N) 338- 002-114-0. This proposed AD was prompted by a normal quality sampling at CFM that isolated a production batch of fan blades with nonconforming geometry of mid-span shroud tips of the fan blades. This defect would cause the upper panel of the fan blade...

30 CFR 57.22204 - Main fan operation and inspection (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main fan operation and inspection (I-A, II-A, III, and V-A mines). 57.22204 Section 57.22204 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Main fan operation and inspection (I-A, II-A, III, and V-A mines). Main fans shall be— (a) Provided...

30 CFR 57.22207 - Booster fans (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Booster fans (I-A, II-A, III, and V-A mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22207 Booster fans (I-A, II-A, III, and V-A mines). (a) Booster fans shall be approved by MSHA under the applicable...

30 CFR 57.22207 - Booster fans (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Booster fans (I-A, II-A, III, and V-A mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22207 Booster fans (I-A, II-A, III, and V-A mines). (a) Booster fans shall be approved by MSHA under the applicable...

30 CFR 57.22207 - Booster fans (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Booster fans (I-A, II-A, III, and V-A mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22207 Booster fans (I-A, II-A, III, and V-A mines). (a) Booster fans shall be approved by MSHA under the applicable...

30 CFR 57.22207 - Booster fans (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Booster fans (I-A, II-A, III, and V-A mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22207 Booster fans (I-A, II-A, III, and V-A mines). (a) Booster fans shall be approved by MSHA under the applicable...

Dynamics of high-bypass-engine thrust reversal using a variable-pitch fan

NASA Technical Reports Server (NTRS)

Schaefer, J. W.; Sagerser, D. R.; Stakolich, E. G.

1977-01-01

The test program demonstrated that successful and rapid forward-to reverse-thrust transients can be performed without any significant engine operational limitations for fan blade pitch changes through either feather pitch or flat pitch. For through-feather-pitch operation with a flight inlet, fan stall problems were encountered, and a fan blade overshoot technique was used to establish reverse thrust.

30 CFR 57.22204 - Main fan operation and inspection (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Main fan operation and inspection (I-A, II-A, III, and V-A mines). 57.22204 Section 57.22204 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Main fan operation and inspection (I-A, II-A, III, and V-A mines). Main fans shall be— (a) Provided...

Noise Generation by Fans with Supersonic Tip Speeds

NASA Technical Reports Server (NTRS)

Glegg, Stewart; Envia, Edmane (Technical Monitor)

2003-01-01

Fan noise continues to be a significant issue for commercial aircraft engines and there still exists a requirement for improved understanding of the fundamental issues associated with fan noise source mechanisms. At the present time, most of the prediction methods identify the dominant acoustic sources to be associated with the stator vanes or blade trailing edges which are downstream of the fan face. However recent studies have shown that acoustic waves are significantly attenuated as they propagate upstream through a rotor, and if the appropriate corrections are applied, sound radiation from the engine inlet is significantly underpredicted. The prediction models can only be applied to fans with subsonic tip speeds. In contrast, most aircraft engines have fan tip speeds which are transonic and this implies an even higher attenuation for upstream propagating acoustic waves. Consequently understanding how sound propagates upstream through the fan is an important, and not well understood phenomena. The objective of this study is to provide improved insight into the upstream propagation effects through a rotor which are relevant to full scale engines. The focus of this study is on broadband fan noise generated by boundary layer turbulence interacting with the trailing edges of the fan blades. If this source mechanism is important upstream of the fan, the sound must propagate upstream through a transonic non uniform flow which includes large gradients and non linearities. Developing acoustic propagation models in this type of flow is challenging and currently limited to low frequency applications, where the frequency is of the same order as the blade passing frequency of the fan. For trailing edge noise, much higher frequencies are relevant and so a suitable approach needs to be developed, which is not limited by an unacceptably large computational effort. In this study we are in the process of developing a computational method which applies for the high frequencies of interest, and allows for any type of flow field associated with the fan. In this progress report the approach to be used and the basic equations will be presented. Some initial results will be given, but these are preliminary and need further verification.

Preliminary results of chronostratigraphic field work, OSL-dating and morphogenetic reconstruction of an alluvial apron at Alborz southern foothill, Damghan basin, Iran

NASA Astrophysics Data System (ADS)

Büdel, Christian; Fuchs, Markus; Majid Padashi, Seyed; Baumhauer, Roland

2014-05-01

Here we present preliminary results of a chronostratigraphic study of an alluvial fan in the Damghan Basin, northern Iran. The basin sediments date back to the Mio- and Pliocene and therefore represent the starting point of alluvial fan aggradation. Today, the still active alluvial fans prograde from the Albors Mountain ranges and sit on the older sediment bodies. In this study, our focus is on the late Pleistocene to Holocene alluvial fan sedimentation history. The upper stratigraphy of the alluvial fans and intercalated lake deposits is characterized by six individual layers of gravels and fines, representing six different stratigraphic units. These units are described and classified by detailed geomorphological and stratigraphic mapping. To establish an alluvial fan chronology, six profiles were sampled for OSL dating. As expected, due to the high-energy transport system of alluvial fan aggradation in semi-desert environments, OSL dating of these sediments is challenging due to the problem of insufficient bleaching. Consequently, most of the samples are interpreted as maximum ages. However, the measurements show a consistent internal age structure and the overall OSL-based chronology is in agreement with the age model derived from our geomorphological analysis. As a first interpretation, based on surveyed geomorphological features and chronological analysis, we could identify seven morphodynamic phases, leading to a genetic model of alluvial fan aggradation. The oldest Pleistocene age estimate is derived from a former lake terrace. The following ages represent ongoing lake sediment deposition and the development of a proximal and mid-fan gravel cover. After the youngest lake deposits were accumulated within the Holocene, the lake starts to retreat and small alluvial fans are filling up the former lake bottom. This last sedimentation phase can be divided in at least two sub-phases, probably coupled to a lateral shifting of the active depositional lobe and to the abandonment and shallow incision of mid fan surfaces.

Authigenic Carbonate Fans from Lower Jurassic Marine Shales (Alberta, Canada)

NASA Astrophysics Data System (ADS)

Martindale, R. C.; Them, T. R., II; Gill, B. C.; Knoll, A. H.

2016-12-01

Authigenic aragonite seafloor fans are a common occurrence in Archean and Paleoproterozoic carbonates, as well as Neoproterozoic cap carbonates. Similar carbonate fans are rare in Phanerozoic strata, with the exception of two mass extinction events; during the Permo-Triassic and Triassic-Jurassic boundaries, carbonate fans formed at the sediment-water interface and within the sediment, respectively. These crystal fans have been linked to carbon cycle perturbations at the end of the Permian and Triassic periods driven by rapid flood volcanism. The Early Jurassic Toarcian Ocean Anoxic Event (T-OAE) is also correlated with the emplacement of a large igneous province, but biological consequences were more modest. We have identified broadly comparable fibrous calcite layers (2-10 cm thick) in Pliensbachian-Toarcian cores from Alberta, Canada. This work focuses on the geochemical and petrographic description of these fans and surrounding sediment in the context of the T-OAE. At the macroscale, carbonates exhibit a fan-like (occasionally cone-in-cone) structure and displace the sediment around them as they grew. At the microscale, the carbonate crystals (pseudomorphs of aragonite) often initiate on condensed horizons or shells. Although they grow in multiple directions (growth within the sediment), the predominant crystal growth direction is towards the sediment-water interface. Resedimentation of broken fans is evidence that crystal growth was penecontemporaneous with sedimentation. The carbon isotope composition of the fans (transects up bladed crystals) and elemental abundances within the layers support shallow subsurface, microbially mediated growth. The resemblance of these Early Jurassic fibrous calcite layers to those found at the end-Triassic and their paucity in the Phanerozoic record suggest that analogous processes occurred at both events. Nevertheless, the Pliensbachian-Toarcian carbonate fans occur at multiple horizons and while some are within the T-OAE, others are significantly above and below the event. The formation of these authigenic layers cannot be driven exclusively by the geochemical and paleoenvironmental changes during the T-OAE. Therefore, a new model of formation for the Early Jurassic carbonate fans is required.

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.

Experimental alluvial fan evolution: Channel dynamics, slope controls, and shoreline growth

NASA Astrophysics Data System (ADS)

Reitz, Meredith D.; Jerolmack, Douglas J.

2012-06-01

River deltas and alluvial fans have channelization and deposition dynamics that are not entirely understood, but which dictate the evolution of landscapes of great social, economic, and ecologic value. Our lack of a process-based understanding of fan dynamics hampers our ability to construct accurate prediction and hazard models, leaving these regions vulnerable. Here we describe the growth of a series of experimental alluvial fans composed of a noncohesive grain mixture bimodal in size and density. We impose conditions that simulate a gravel/sand fan prograding into a static basin with constant water and sediment influx, and the resulting fans display realistic channelization and avulsion dynamics. We find that we can describe the dynamics of our fans in terms of a few processes: (1) an avulsion sequence with a timescale dictated by mass conservation between incoming flux and deposit volume; (2) a tendency for flow to reoccupy former channel paths; and (3) bistable slopes corresponding to separate entrainment and deposition conditions for grains. Several important observations related to these processes are: an avulsion timescale that increases with time and decreases with sediment feed rate; fan lobes that grow in a self-similar, quasi-radial pattern; and channel geometry that is adjusted to the threshold entrainment stress. We propose that the formation of well-defined channels in noncohesive fans is a transient phenomenon resulting from incision following avulsion, and can be directly described with dual transport thresholds. We present a fairly complete, process-based description of the mechanics of avulsion and its resulting timescale on our fans. Because the relevant dynamics depend only on threshold transport conditions and conservation of mass, we show how results may be directly applied to field-scale systems.

Supplementary catalogue of the Anthomyiidae (Diptera) of China

PubMed Central

Wang, Mengmeng; Michelsen, Verner; Li, Kai; Zhu, Weibing

2014-01-01

Abstract The present catalogue of Anthomyiidae attempts to list all species (173) described or recorded from mainland China (165) and Taiwan (8) that for various reasons are not treated in “Flies of China” from 1998. The catalogue further lists Chinese species that are presently standing in new generic combinations compared to those of “Flies of China”, species that have changed name because of synonymy or misidentification, and species upgraded from subspecies to species. Regional distribution by province is specified for all species. Literature sources to descriptions or records of anthomyiid species from China are only given for those 173 species not covered by “Flies of China”. Four new combinations are proposed: Enneastigma fulva (Malloch, 1934), Enneastigma henanensis (Ge & Fan, 1982), Enneastigma lengshanensis (Xue, 2001) and Hylemya qinghaiensis (Fan, Chen & Ma, 1989). Eremomyia turbida Huckett, 1951 is revived from synonymy with Chortophila triticiperda Stein, 1900 (current name Eutrichota turbida). One subspecies is upgraded to species: Adia asiatica Fan, 1988. The following eight new synonymies are proposed: Delia pectinator fuscilateralis Fan in Fan & Zheng, 1992 with Delia pectinator Suwa, 1984; Eremomyia pilimana pilimarginata Fan & Qian in Fan, Chen, Ma & Ge, 1982 with Eremomyia turbida Huckett, 1951 (current name Eutrichota turbida); Lopesohylemya Fan, Chen & Ma, 1989 with Hylemya Robineau-Desvoidy, 1830; Deliomyia Fan in Fan et al., 1988 with Subhylemyia Ringdahl, 1933; Hydrophoria disticrassa Xue & Bai, 2009 with Hydrophoria pullata Wu, Liu & Wei, 1995 (current name Zaphne pullata); Heteroterma Wei, 2006 with Scathophaga Meigen, 1803; Heteroterma fanjingensis Wei, 2006 with Scathophaga curtipilata Feng, 2002; Scatomyza fansipanicola Ozerov in Ozerov & Krivosheina, 2011 with Scathophaga curtipilata Feng, 2002. The genus Heteroterma Wei, 2006 and species Heteroterma fanjingensis Wei, 2006 are reassigned from Anthomyiidae to Scathophagidae. PMID:25493060

Bahía de Banderas, Mexico: Morphology, Magnetic Anomalies and Shallow Structure

NASA Astrophysics Data System (ADS)

Mortera Gutiérrez, Carlos A.; Bandy, William L.; Ponce Núñez, Francisco; Pérez Calderón, Daniel A.

2016-10-01

The Bahía de Banderas lies within a tectonically complex area at the northern end of the Middle America Trench. The structure, morphology, subsurface geology and tectonic history of the bay are essential for unraveling the complex tectonic processes occurring in this area. With this focus, marine geophysical data (multi-beam bathymetry, high resolution seismic reflection and total field magnetic data) were collected within the bay and adjacent areas during four campaigns aboard the B.O. EL PUMA conducted in 2006 and 2009. These data image the detailed morphology of, and sedimentation patterns within, the Banderas Canyon (a prominent submarine canyon situated on the south side of the bay) as well as the shallow subsurface structure of the northern part of the bay and the submarine Marietas Ridge, which bounds the bay to the west. We find that the Marietas Ridge is presently a transtensional feature; the course of the Banderas Canyon is controlled by extensive turbidite fan sedimentation in its eastern extremity and by structural lineaments to the west; the canyon floor is filled by sediments and exhibits almost no evidence for recent tectonic movements; the southern canyon wall is quite steep and a few sediments are deposited as submarine fans at the base of the southern wall; and extensive turbidite fans form the lower part of the northern canyon wall, producing a gently sloping lower northern wall. We find no evidence for a regional east-west striking lineament between the bay and the Middle America Trench, which casts doubts on the previous assertion that the Banderas Canyon is unequivocally related to the presence of a regional half-graben. Finally, a N71°E oriented normal fault offsets the seafloor reflector by 15 m within the central part of the bay, suggesting that the bay is currently being subjected to NNW-SSE extension.

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.

Unducted, counterrotating gearless front fan engine

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

Taylor, J.B.

This patent describes a high bypass ratio gas turbine engine. It comprises a core engine effective for generating combustion gases passing through a main flow path; a power turbine aft of the core engine and including first and second counter rotatable interdigitated turbine blade rows, effective for counterrotating first and second drive shafts, respectively; an unducted fan section forward of the core engine including a first fan blade row connected to the first drive shaft and a second fan blade row axially spaced aftward from the first fan blade row and connected to the second drive shaft; and a boostermore » compressor axially positioned between the first and second fan blade rows and including first compressor blade rows connected to the first drive shaft and second compressor blade rows connected to the second drive shaft.« less

Alcohol-related fan behavior on college football game day.

PubMed

Glassman, Tavis; Werch, Chudley E; Jobli, Edessa; Bian, Hui

2007-01-01

High-risk drinking on game day represents a unique public health challenge. The authors examined the drinking behavior of college football fans and assessed the support for related interventions. The authors randomly selected 762 football fans, including college students, alumni, and other college football fans, to complete an anonymous online game-day survey. The authors collected data on participants' drinking behaviors and support for specific game-day interventions. Analysis revealed that, overall, fans drank significantly more on game day than they did the last time they partied or socialized. Nondrinkers were the most supportive of game-day interventions, followed by moderate drinkers, whereas heavy drinkers offered the least support. With the exception of limiting tailgating hours on game day, fans support game-day interventions, including alcohol-free alternatives, designating tailgating areas where open containers are permitted, and increasing law enforcement efforts.

Portable Fan Assembly for the International Space Station

NASA Technical Reports Server (NTRS)

Jenkins, Arthur A.; Roman, Monsi C.

1999-01-01

NASA/ Marshall Space Flight Center (NASA/MSFC) is responsible for the design and fabrication of a Portable Fan Assembly (PFA) for the International Space Station (ISS). The PFA will be used to enhance ventilation inside the ISS modules as needed for crew comfort and for rack rotation. The PFA consists of the fan on-orbit replaceable unit (ORU) and two noise suppression packages (silencers). The fan ORU will have a mechanical interface with the Seat Track Equipment Anchor Assembly, in addition to the power supply module which includes a DC-DC converter, on/standby switch, speed control, power cable and connector. This paper provides a brief development history, including the criteria used for the fan, and a detailed description of the PFA operational configurations. Space Station requirements as well as fan performance characteristics are also discussed.

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.

Integrated propulsion/energy transfer control systems for lift-fan V/STOL aircraft. [reduction of total propulsion system and control system installation requirements

NASA Technical Reports Server (NTRS)

Deckert, W. H.; Rolls, L. S.

1974-01-01

An integrated propulsion/control system for lift-fan transport aircraft is described. System behavior from full-scale experimental and piloted simulator investigations are reported. The lift-fan transport is a promising concept for short-to-medium haul civil transportation and for other missions. The lift-fan transport concept features high cruise airspeed, favorable ride qualities, small perceived noise footprints, high utilization, transportation system flexibility, and adaptability to VTOL, V/STOL, or STOL configurations. The lift-fan transport has high direct operating costs in comparison to conventional aircraft, primarily because of propulsion system and aircraft low-speed control system installation requirements. An integrated lift-fan propulsion system/aircraft low-speed control system that reduces total propulsion system and control system installation requirements is discussed.

Single stage, low noise, advanced technology fan. Volume 5: Fan acoustics. Section 1: Results and analysis

NASA Technical Reports Server (NTRS)

Jutras, R. R.

1976-01-01

The acoustic tests and data analysis for a 0.508-scale fan vehicle of a 111,300 newton (25,000 pound) thrust, full-size engine, which would have application on an advanced transport aircraft, is described. The single-stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec (1,650 ft/sec) to achieve the desired pressure ratio in a single-stage fan with low radius ratio (0.38), and to maintain adequate stall margin. The fan has 44 tip-shrouded rotor blades and 90 outlet guide vanes. The two basic approaches taken in the acoustic design were: (1) minimization of noise at the source, and (2) suppression of the generated noise in the inlet and bypass exhaust duct. Suppression of the generated noise was accomplished in the inlet through use of the hybrid concept (wall acoustic treatment plus airflow acceleration suppression) and in the exhaust duct with extensive acoustic treatment including a splitter. The goal of the design was attainment of twenty effective perceived noise decibels (20 EPNdB) below current Federal Air Regulation noise standards for a full-scale fan at the takeoff, cutback, and approach conditions. The suppression goal of FAR 36-20 was not reached, but improvements in the technology of both front and aft fan-noise suppression were realized. The suppressed fan noise was shown to be consistent with the proposed federal regulation on aircraft noise.

Noise comparison of two 1.2-pressure-ratio fans with 15 and 42 rotor blades

NASA Technical Reports Server (NTRS)

Woodward, R. P.; Glaser, F. W.; Wazyniak, J. A.

1973-01-01

Two 1.829-m-(6-ft-) diameter fans suitable for a quiet engine for future short-takeoff-and-landing (STOL) aircraft were compared. Both fans were designed for a 1.2 pressure ratio with similar weight flows, thrusts, and tip speeds. The first fan, designated QF-9, had 15 rotor blades and 11 stator blades. The rotor was highly loaded and the tip solidity was less than 1. The QF-9 rotor blades had an adjustable pitch feature which can be used for thrust reversal. The second fan, designated QF-6, operated at a moderate loading with a rotor tip solidity greater than 1. Fan QF-6 had 42 rotor blades and 50 stator blades. The low number of rotor blades for QF-9 reduced the frequency of the blade-passage tone below the range of maximum annoyance. In addition to this difference, the QF-9 fan had a somewhat smaller rotor-stator separation than the QF-6 fan. In terms of sound pressure level and sound power level, QF-9 was the noisier fan, with the power level results for QF-9 being about 1 db above those for QF-6 at equivalent operating points as determined by similar stage pressure ratios. At the same equivalent operating points, the maximum perceived noise along a 152.5-m (500-ft) sideline for QF-9 was about 2.5 PNdb below that for QF-6, which indicated that QF-9 was less objectionable to human hearing.

Portable Life Support System 2.5 Fan Design and Development

NASA Technical Reports Server (NTRS)

Quinn, Gregory; Carra, Michael; Converse, David; Chullen, Cinda

2016-01-01

NASA is building a high-fidelity prototype of an advanced Portable Life Support System (PLSS) as part of the Advanced Exploration Systems Program. This new PLSS, designated as PLSS 2.5, will advance component technologies and systems knowledge to inform a future flight program. The oxygen ventilation loop of its predecessor, PLSS 2.0, was driven by a centrifugal fan developed using specifications from the Constellation Program. PLSS technology and system parameters have matured to the point where the existing fan will not perform adequately for the new prototype. In addition, areas of potential improvement were identified with the PLSS 2.0 fan that could be addressed in a new design. As a result, a new fan was designed and tested for the PLSS 2.5. The PLSS 2.5 fan is a derivative of the one used in PLSS 2.0, and it uses the same nonmetallic, canned motor, with a larger volute and impeller to meet the higher pressure drop requirements of the PLSS 2.5 ventilation loop. The larger impeller allows it to operate at rotational speeds that are matched to rolling element bearings, and which create reasonably low impeller tip speeds consistent with prior, oxygen-rated fans. Development of the fan also considered a shrouded impeller design that could allow larger clearances for greater oxygen safety, assembly tolerances and particle ingestion. This paper discusses the design, manufacturing and performance testing of the new fans.

Comparison of inversion models using AIRSAR data for Death Valley, California

NASA Technical Reports Server (NTRS)

Kierein-Young, Kathryn S.

1993-01-01

Polarimetric Airborne Synthetic Aperture Radar (AIRSAR) data were collected for the Geologic Remote Sensing Field Experiment (GRSFE) over Death Valley, California, USA, in September 1989. AIRSAR is a four-look, quid-polarizaiton, three frequency instrument. It collects measurements at C-band (5.66 cm), L-band (23.98 cm), and P-band (68.13 cm), and has a GIFOV of 10 meters and a swath width of 12 kilometers. Because the radar measures at three wavelengths, different scales of surface roughness are measured. Also, dielectric constants can be calculated from the data. The scene used in this study is in Death Valley, California and is located over Trail Canyon alluvial fan, the valley floor, and Artists Drive alluvial fan. The fans are very different in mineralogic makeup, size, and surface roughness. Trail Canyon fan is located on the west side of the valley at the base of the Panamint Range and is a large fan with older areas of desert pavement and younger active channels. The source for the material on southern part of the fan is mostly quartzites and there is an area of carbonate source on the northern part of the fan. Artists Drive fan is located at the base of the Black Mountains on the east side of the valley and is a smaller, young fan with its source mostly from volcanic rocks. The valley floor contains playa and salt deposits that range from smooth to Devil's Golf course type salt pinnacles.

Numerical ages of Holocene tributary debris fans inferred from dissolution pitting on carbonate boulders in the Grand Canyon of Arizona

USGS Publications Warehouse

Hereford, R.; Thompson, K.S.; Burke, K.J.

1998-01-01

Carbonate boulders transported down steep tributary channels by debris flow came to rest on Holocene debris fans beside the Colorado River in Grand Canyon National Park. Weakly acidic rainfall and the metabolic activity of blue-green algae have produced roughly hemispheric dissolution pits as much as 2-cm deep on the initially smooth surfaces of the boulders. The average depth of dissolution pits increases with relative age of fan surfaces. The deepening rate averages 2.4 mm/1000 yr (standard error = 0.2 mm/1000 yr), as calculated from several radiometrically dated surfaces and an archeological structure. This linear rate, which appears constant over at least the past 3000 yr, is consistent with field relations limiting the maximum age of the fans and with the physical chemistry of limestone dissolution. Dissolution-pit measurements (n = 6973) were made on 617 boulders on 71 fan surfaces at the 26 largest debris fans in Grand Canyon. Among these fan surfaces, the average pit depth ranges from 1.2 to 17.4 mm, and the resulting pit dissolution ages range from 500 to 7300 cal yr B.P. Most (75%) surfaces are younger than 3000 yr, probably because of removal of older debris fans by the Colorado River. Many of the ages are close to 800, 1600, 2300, 3100, or 4300 cal yr B.P. If not the result of differential preservation of fan surfaces, this clustering implies periods of heightened debris-flow activity and increased precipitation.

Response Sensitivity of Typical Aircraft Jet Engine Fan Blade-Like Structures to Bird Impacts.

DTIC Science & Technology

1982-05-01

AIRCRAFT ENGINE BU--ETC F/G 21/5 RESPONSE SENSITIVITY OF TYPICAL AIRCRAFT JET ENGINE FAN BLADE -L...SENSITIVITY OF TYPICAL AIRCRAFT JET ENGINE FAN BLADE -LIKE STRUCTURES TO BIRD IMPACTS David P. Bauer Robert S. Bertke University of Dayton Research...COVERED RESPONSE SENSITIVITY OF TYPICAL AIRCRAFT FINAL REPORT JET ENGINE FAN BLADE -LIKE STRUCTURES Oct. 1977 to Jan. 1979 TO BIRD IMPACTS s.

76 FR 70336 - Airworthiness Directives; Rolls-Royce plc RB211-524G2-19; -524G2-T-19; -524G3-19; -524G3-T-19...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-14

... caused by fan blade flutter at certain engine settings during prolonged ground running. This condition, if not corrected, could affect the integrity of the fan blades, leading to cracking of multiple fan... aviation product. The MCAI describes the unsafe condition as: Several instances of fan blade cracking have...

Aircraft Engine Exhaust Nozzle System for Jet Noise Reduction

NASA Technical Reports Server (NTRS)

Thomas, Russell H. (Inventor); Czech, Michael J. (Inventor); Elkoby, Ronen (Inventor)

2014-01-01

The aircraft exhaust engine nozzle system includes a fan nozzle to receive a fan flow from a fan disposed adjacent to an engine disposed above an airframe surface of the aircraft, a core nozzle disposed within the fan nozzle and receiving an engine core flow, and a pylon structure connected to the core nozzle and structurally attached with the airframe surface to secure the engine to the aircraft.

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.

Intelligent Prediction of Fan Rotation Stall in Power Plants Based on Pressure Sensor Data Measured In-Situ

PubMed Central

Xu, Xiaogang; Wang, Songling; Liu, Jinlian; Liu, Xinyu

2014-01-01

Blower and exhaust fans consume over 30% of electricity in a thermal power plant, and faults of these fans due to rotation stalls are one of the most frequent reasons for power plant outage failures. To accurately predict the occurrence of fan rotation stalls, we propose a support vector regression machine (SVRM) model that predicts the fan internal pressures during operation, leaving ample time for rotation stall detection. We train the SVRM model using experimental data samples, and perform pressure data prediction using the trained SVRM model. To prove the feasibility of using the SVRM model for rotation stall prediction, we further process the predicted pressure data via wavelet-transform-based stall detection. By comparison of the detection results from the predicted and measured pressure data, we demonstrate that the SVRM model can accurately predict the fan pressure and guarantee reliable stall detection with a time advance of up to 0.0625 s. This superior pressure data prediction capability leaves significant time for effective control and prevention of fan rotation stall faults. This model has great potential for use in intelligent fan systems with stall prevention capability, which will ensure safe operation and improve the energy efficiency of power plants. PMID:24854057

New Set of Fan Blades for the Altitude Wind Tunnel

NASA Image and Video Library

1951-08-21

New wooden fan blades being prepared for installation in the Altitude Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The facility underwent a major upgrade in 1951 to increase its operating capacities in order to handle the new, more powerful turbojet engines being manufactured in the 1950s. The fan blades were prepared in the shop area, seen in this photograph, before being lowered through a hole in the tunnel and attached to the drive shaft. A new drive bearing and tail faring were also installed on the fan as part of this rehab project. A 12-bladed 31-foot-diameter spruce wood fan generated the 300 to 500 mile-per-hour airflow through the tunnel. An 18,000-horsepower General Electric induction motor located in the rear corner of the Exhauster Building drove the fan at 410 revolutions per minute. An extension shaft, sealed in the tunnel’s shell with flexible couplings that allowed for the movement of the shell, connected the motor to the fan. A bronze screen secured to the turning vanes protected the fan against damage from any engine parts sailing through the tunnel. Despite this screen the blades did become worn or cracked over time and had to be replaced.

Risk Identification and Prediction of Coal Workers’ Pneumoconiosis in Kailuan Colliery Group in China: A Historical Cohort Study

PubMed Central

Shen, Fuhai; Yuan, Juxiang; Sun, Zhiqian; Hua, Zhengbing; Qin, Tianbang; Yao, Sanqiao; Fan, Xueyun; Chen, Weihong; Liu, Hongbo; Chen, Jie

2013-01-01

Background Prior to 1970, coal mining technology and prevention measures in China were poor. Mechanized coal mining equipment and advanced protection measures were continuously installed in the mines after 1970. All these improvements may have resulted in a change in the incidence of coal workers’ pneumoconiosis (CWP). Therefore, it is important to identify the characteristics of CWP today and trends for the incidence of CWP in the future. Methodology/Principal Findings A total of 17,023 coal workers from the Kailuan Colliery Group were studied. A life-table method was used to calculate the cumulative incidence rate of CWP and predict the number of new CWP patients in the future. The probability of developing CWP was estimated by a multilayer perceptron artificial neural network for each coal worker without CWP. The results showed that the cumulative incidence rates of CWP for tunneling, mining, combining, and helping workers were 31.8%, 27.5%, 24.2%, and 2.6%, respectively, during the same observation period of 40 years. It was estimated that there would be 844 new CWP cases among 16,185 coal workers without CWP within their life expectancy. There would be 273.1, 273.1, 227.6, and 69.9 new CWP patients in the next <10, 10-, 20-, and 30- years respectively in the study cohort within their life expectancy. It was identified that coal workers whose risk probabilities were over 0.2 were at high risk for CWP, and whose risk probabilities were under 0.1 were at low risk. Conclusion/Significance The present and future incidence trends of CWP remain high among coal workers. We suggest that coal workers at high risk of CWP undergo a physical examination for pneumoconiosis every year, and the coal workers at low risk of CWP be examined every 5 years. PMID:24376519

Review of noise reduction methods for centrifugal fans

NASA Astrophysics Data System (ADS)

Neise, W.

1981-11-01

Several methods for the reduction of centrifugal fan noise are presented, the most of which are aimed at a lower blade passage frequency level. The methods are grouped into five categories: casing modifications to increase the distance between impeller and cutoff, the introduction of a phase shift of the source pressure fluctuations, impeller modifications, radial clearance between impeller eye and inlet nozzle, and acoustical measures. Resonators mounted at the cutoff of centrifugal fans appear to be a highly efficient and simple means of reducing the blade passage tone, and the method can be used for new fan construction and existing installations without affecting the aerodynamic performance of the fan.

Fan Cart: The Next Generation

NASA Astrophysics Data System (ADS)

Lamore, Brian

2016-10-01

For years the fan cart has provided physics students with an excellent resource for exploring fundamental mechanics concepts such as acceleration, Newton's laws, impulse, momentum, work-energy, and energy conversions. The Physics Teacher has even seen some excellent do-it-yourself (DIY) fan carts and activities. If you are interested in developing the `E' portion of your and your students' STEM (science, technology, engineering, and math) skills, one way to accomplish this is to revisit the DIY fan cart. In this article I share a design of a new edition of the DIY fan cart and some ideas for incorporating the engineering design process into your high school curriculum.

The Shape of Trail Canyon Alluvial Fan, Death Valley

NASA Technical Reports Server (NTRS)

Farr, Tom G.; Dohrenwend, John C.

1993-01-01

A modified conic equation has been fit to high-resolution digital topographic data for Trail Canyon alluvial fan in Death Valley, California. Fits were accomplished for 3 individual fan units of different age.

Alluvial Fans in Mojave Crater

NASA Image and Video Library

2015-05-20

This image from NASA Mars Reconnaissance Orbiter shows a landscape that is pervasively eroded, right up to the tops of the ridges, with channels extending down into depositional fans much like alluvial fans in the Mojave Desert.

Advanced Noise Control Fan (ANCF)

NASA Image and Video Library

2014-01-15

The Advanced Noise Control Fan shown here is located in NASA Glenn’s Aero-Acoustic Propulsion Laboratory. The 4-foot diameter fan is used to evaluate innovate aircraft engine noise reduction concepts less expensively and more quickly.

Deeper and sparser nets are optimal

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

Beiu, V.; Makaruk, H.E.

1998-03-01

The starting points of this paper are two size-optimal solutions: (1) one for implementing arbitrary Boolean functions (Home and Hush, 1994); and (2) another one for implementing certain sub-classes of Boolean functions (Red`kin, 1970). Because VLSI implementations do not cope well with highly interconnected nets--the area of a chip grows with the cube of the fan-in (Hammerstrom, 1988)--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 Home and Hush (1994) valid for fan-in {Delta} = 2 to arbitrary fan-in. Second, they will provemore » that size-optimal solutions are obtained for small constant fan-in 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 (Beiu, 1997a), while there are similar small constants relating to the capacity of processing information (Miller 1956).« less

Deeper sparsely nets are size-optimal

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

Beiu, V.; Makaruk, H.E.

1997-12-01

The starting points of this paper are two size-optimal solutions: (i) one for implementing arbitrary Boolean functions (Horne, 1994); and (ii) another one for implementing certain sub-classes of Boolean functions (Red`kin, 1970). Because VLSI implementations do not cope well with highly interconnected nets--the area of a chip grows with the cube of the fan-in (Hammerstrom, 1988)--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 (1994) valid for fan-in {Delta} = 2 to arbitrary fan-in. Second, they will prove that size-optimalmore » solutions are obtained for small constant fan-in for both constructions, while relative minimum size solutions can be obtained for fan-ins strictly lower than 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 (Beiu, 1997a), while there are similar small constants relating to the capacity of processing information (Miller 1956).« less

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.

Constructing the Hydrogeological Model of the Choushuichi Fan-delta in Central Taiwan with the Electrical Resistivity Measurements

NASA Astrophysics Data System (ADS)

Chang, P.; Chang, L.; Chen, W.; Chiang, C.

2012-12-01

In the study we used the resistivity measurements across the Choushuichi Fan-delta to establish a three-dimensional hydrogeological model. The resistivity measurements includes the half-Schlumberger surveys conducted during the year of 1990-2000 across the entire fan-delta area, and the two-dimensional resistivity data collected recently for the purpose of characterizing the recharge zone boundaries between the upper-fan gravels and the lower-fan clayey sediments. Core records from the monitoring wells in the area were used for the training data to help determining the resistivity ranges of the gavel, sand, and muddy sediments in the fan-delta. The resistivity measurements were inverted and converted into 1-D data form and interpolated for rendering a three dimensional resistivity volume that represents the general resistivity distribution in the Choushuichi fan-delta. We categorize the hydrogeological materials into gravels, sands, and clayey sediments with the resistivity ranges from the previous statistical analysis. Hence we are able to quickly construct a three-dimensional hydrogeological model with simple three materials.

Topological and Geometric Tools for the Analysis fo Complex Networks

DTIC Science & Technology

2013-10-01

CONTRACT NUMBER FA 9550-09-1-0090 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) Ali Jadbabaie (Penn) Shing-Tung Yau (Harvard) Fan Chung...NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) University of Pennsylvania 34th and Spruce Street, Philadelphia 19104-6303 8. PERFORMING...ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) Air Force Office of Scientific Research 875 North Randolph Street

Implications for the origins of pure anorthosites found in the feldspathic lunar meteorites, Dhofar 489 group

NASA Astrophysics Data System (ADS)

Nagaoka, Hiroshi; Takeda, Hiroshi; Karouji, Yuzuru; Ohtake, Makiko; Yamaguchi, Akira; Yoneda, Shigekazu; Hasebe, Nobuyuki

2014-12-01

Remote observation by the reflectance spectrometers onboard the Japanese lunar explorer Kaguya (SELENE) showed the purest anorthosite (PAN) spots (>98% plagioclase) at some large craters. Mineralogical and petrologic investigations on the feldspathic lunar meteorites, Dhofar 489 and Dhofar 911, revealed the presence of several pure anorthosite clasts. A comparison with Apollo nearside samples of ferroan anorthosite (FAN) indicated that of the FAN samples returned by the Apollo missions, sample 60015 is the largest anorthosite with the highest plagioclase abundance and homogeneous mafic mineral compositions. These pure anorthosites (>98% plagioclase) have large chemical variations in Mg number (Mg# = molar 100 × Mg/(Mg + Fe)) of each coexisting mafic mineral. The variations imply that these pure anorthosites underwent complex formation processes and were not formed by simple flotation of plagioclase. The lunar highland samples with pure anorthosite and the PAN observed by Kaguya suggest that pure anorthosite is widely distributed as lunar crust lithology over the entire Moon.

Enhanced Amplification and Fan-Out Operation in an All-Magnetic Transistor

PubMed Central

Barman, Saswati; Saha, Susmita; Mondal, Sucheta; Kumar, Dheeraj; Barman, Anjan

2016-01-01

Development of all-magnetic transistor with favorable properties is an important step towards a new paradigm of all-magnetic computation. Recently, we showed such possibility in a Magnetic Vortex Transistor (MVT). Here, we demonstrate enhanced amplification in MVT achieved by introducing geometrical asymmetry in a three vortex sequence. The resulting asymmetry in core to core distance in the three vortex sequence led to enhanced amplification of the MVT output. A cascade of antivortices travelling in different trajectories including a nearly elliptical trajectory through the dynamic stray field is found to be responsible for this amplification. This asymmetric vortex transistor is further used for a successful fan-out operation, which gives large and nearly equal gains in two output branches. This large amplification in magnetic vortex gyration in magnetic vortex transistor is proposed to be maintained for a network of vortex transistor. The above observations promote the magnetic vortex transistors to be used in complex circuits and logic operations. PMID:27624662

Mesoscale Graphene-like Honeycomb Mono- and Multilayers Constructed via Self-Assembly of Coclusters.

PubMed

Hou, Xue-Sen; Zhu, Guo-Long; Ren, Li-Jun; Huang, Zi-Han; Zhang, Rui-Bin; Ungar, Goran; Yan, Li-Tang; Wang, Wei

2018-02-07

Honeycomb structure endows graphene with extraordinary properties. But could a honeycomb monolayer superlattice also be generated via self-assembly of colloids or nanoparticles? Here we report the construction of mono- and multilayer molecular films with honeycomb structure that can be regarded as self-assembled artificial graphene (SAAG). We construct fan-shaped molecular building blocks by covalently connecting two kinds of clusters, one polyoxometalate and four polyhedral oligomeric silsesquioxanes. The precise shape control enables these complex molecules to self-assemble into a monolayer 2D honeycomb superlattice that mirrors that of graphene but on the mesoscale. The self-assembly of the SAAG was also reproduced via coarse-grained molecular simulations of a fan-shaped building block. It revealed a hierarchical process and the key role of intermediate states in determining the honeycomb structure. Experimental images also show a diversity of bi- and trilayer stacking modes. The successful creation of SAAG and its stacks opens up prospects for the preparation of novel self-assembled nanomaterials with unique properties.

Task 7: Endwall treatment inlet flow distortion analysis

NASA Technical Reports Server (NTRS)

Hall, E. J.; Topp, D. A.; Heidegger, N. J.; McNulty, G. S.; Weber, K. F.; Delaney, R. A.

1996-01-01

The overall objective of this study was to develop a 3-D numerical analysis for compressor casing treatment flowfields, and to perform a series of detailed numerical predictions to assess the effectiveness of various endwall treatments for enhancing the efficiency and stall margin of modern high speed fan rotors. Particular attention was given to examining the effectiveness of endwall treatments to counter the undesirable effects of inflow distortion. Calculations were performed using three different gridding techniques based on the type of casing treatment being tested and the level of complexity desired in the analysis. In each case, the casing treatment itself is modeled as a discrete object in the overall analysis, and the flow through the casing treatment is determined as part of the solution. A series of calculations were performed for both treated and untreated modern fan rotors both with and without inflow distortion. The effectiveness of the various treatments were quantified, and several physical mechanisms by which the effectiveness of endwall treatments is achieved are discussed.

Liquefaction and soil failure during 1994 northridge earthquake

USGS Publications Warehouse

Holzer, T.L.

1999-01-01

The 1994 Northridge, Calif., earthquake caused widespread permanent ground deformation on the gently sloping alluvial fan surface of the San Fernando Valley. The ground cracks and distributed deformation damaged both pipelines and surface structures. To evaluate the mechanism of soil failure, detailed subsurface investigations were conducted at four sites. Three sites are underlain by saturated sandy silts with low standard penetration test and cone penetration test values. These soils are similar to those that liquefied during the 1971 San Fernando earthquake, and are shown by widely used empirical relationships to be susceptible to liquefaction. The remaining site is underlain by saturated clay whose undrained shear strength is approximately half the value of the earthquake-induced shear stress at this location. This study demonstrates that the heterogeneous nature of alluvial fan sediments in combination with variations in the ground-water table can be responsible for complex patterns of permanent ground deformation. It may also help to explain some of the spatial variability of strong ground motion observed during the 1994 earthquake. ?? ASCE,.

Evaluation of two inflow control devices for flight simulation of fan noise using a JT15D engine

NASA Technical Reports Server (NTRS)

Jones, W. L.; Mcardle, J. G.; Homyak, L.

1979-01-01

The program was developed to accurately simulate flight fan noise on ground static test stands. The results generally indicated that both the induct and external ICD's were effective in reducing the inflow turbulence and the fan blade passing frequency tone generated by the turbulence. The external ICD was essentially transparent to the propagating fan tone but the induct ICD caused attenuation under most conditions.

Evaluation of Resuspension from Propeller Wash in DoD Harbors

DTIC Science & Technology

2016-09-01

Environmental Research and Development Center FANS FOV ICP-MS Finite Analytical Navier-Stoker Solver Field of View Inductively Coupled Plasma with...Model (1984) and the Finite Analytical Navier- Stoker Solver (FANS) model (Chen et al., 2003) were set up to simulate and evaluate flow velocities and...model for evaluating the resuspension potential of propeller wash by a tugboat and the FANS model for a DDG. The Finite -Analytic Navier-Stokes (FANS

Wind tunnel performance results of an aeroelastically scaled 2/9 model of the PTA flight test prop-fan

NASA Technical Reports Server (NTRS)

Stefko, George L.; Rose, Gayle E.; Podboy, Gary G.

1987-01-01

High speed wind tunnel aerodynamic performance tests of the SR-7A advanced prop-fan have been completed in support of the Prop-Fan Test Assessment (PTA) flight test program. The test showed that the SR-7A model performed aerodynamically very well. At the cruise design condition, the SR-7A prop fan had a high measured net efficiency of 79.3 percent.

Acting on Lessons Learned: A NASA Glenn Acoustics Branch Perspective

NASA Technical Reports Server (NTRS)

Koch, L. Danielle

2008-01-01

Lessons learned from the International Space Station have indicated that early attention to acoustics will be key to achieving safer, more productive environments for new long duration missions. Fans are known to be dominant noise sources, and reducing fan noise poses challenges for fan manufacturers and systems engineers. The NASA Glenn Acoustics Branch has considered ways in which expertise and capabilities traditionally used to understand and mitigate aircraft engine noise can be used to address small fan noise issues in Exploration and Information Technology applications. Many could benefit if NASA can capture what is known about small fan aero and acoustic performance in a "Guide for the Design, Selection, and Installation of Fans for Spaceflight Applications." A draft outline for this document will be offered as a useful starting point for brainstorming ideas for the various smaller, near-term research projects that would need to be addressed first.

Shape Changing Airfoil

NASA Technical Reports Server (NTRS)

Ott, Eric A.

2005-01-01

Scoping of shape changing airfoil concepts including both aerodynamic analysis and materials-related technology assessment effort was performed. Three general categories of potential components were considered-fan blades, booster and compressor blades, and stator airfoils. Based on perceived contributions to improving engine efficiency, the fan blade was chosen as the primary application for a more detailed assessment. A high-level aerodynamic assessment using a GE90-90B Block 4 engine cycle and fan blade geometry indicates that blade camber changes of approximately +/-4deg would be sufficient to result in fan efficiency improvements nearing 1 percent. Constraints related to flight safety and failed mode operation suggest that use of the baseline blade shape with actuation to the optimum cruise condition during a portion of the cycle would be likely required. Application of these conditions to the QAT fan blade and engine cycle was estimated to result in an overall fan efficiency gain of 0.4 percent.

Fault detection and diagnosis for refrigerator from compressor sensor

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

Keres, Stephen L.; Gomes, Alberto Regio; Litch, Andrew D.

A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identifiedmore » if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.« less

V/STOL model fan stage rig design report

NASA Technical Reports Server (NTRS)

Cheatham, J. G.; Creason, T. L.

1983-01-01

A model single-stage fan with variable inlet guide vanes (VIGV) was designed to demonstrate efficient point operation while providing flow and pressure ratio modulation capability required for a V/STOL propulsion system. The fan stage incorporates a split-flap VIGV with an independently actuated ID flap to permit independent modulation of fan and core engine airstreams, a flow splitter integrally designed into the blade and vanes to completely segregate fan and core airstreams in order to maximize core stream supercharging for V/STOL operation, and an EGV with a variable leading edge fan flap for rig performance optimization. The stage was designed for a maximum flow size of 37.4 kg/s (82.3 lb/s) for compatibility with LeRC test facility requirements. Design values at maximum flow for blade tip velocity and stage pressure ratio are 472 m/s (1550 ft/s) and 1.68, respectively.

Effect of rotor design tip speed on noise of a 1.21 pressure ratio model fan under static conditions

NASA Technical Reports Server (NTRS)

Loeffler, I. J.; Lieblein, S.; Stockman, N. O.

1973-01-01

Preliminary results are presented for a reverberant-field noise investigation of three fan stages designed for the same overall total pressure ratio of 1.21 at different rotor tip speeds (750, 900, and 1050 ft/sec). The stages were tested statically in a 15-inch-diameter model lift fan installed in a wing pod located in the test section of a wind tunnel. Although the fan stages produced essentially the same design pressure ratio, marked differences were observed in the variation of fan noise with fan operating speed. At design speed, the forward-radiated sound power level was approximately the same for the 750 ft/sec and 900 ft/sec stages. For the 1050 ft/sec stage, the design-speed forward-radiated power level was about 7 db higher due to the generation of multiple pure tone noise.