753 research outputs found
Static internal performance of convergent single-expansion-ramp nozzles with various combinations of internal geometric parameters
An investigation was conducted in the Static Test Facility of the Langley 16-Foot Transonic Tunnel to determine the effects of five geometric design parameters on the internal performance of convergent single expansion ramp nozzles. The effects of ramp chordal angle, initial ramp angle, flap angle, flap length, and ramp length were determined. All nozzles tested has a nominally constant throat area and aspect ratio. Static pressure distributions along the centerlines of the ramp and flap were also obtained for each configuration. Nozzle pressure ratio was varied up to 10.0 for all configurations
Multiaxis control power from thrust vectoring for a supersonic fighter aircraft model at Mach 0.20 to 2.47
The aeropropulsive characteristics of an advanced twin-engine fighter aircraft designed for supersonic cruise have been studied in the Langley 16-Foot Tansonic Tunnel and the Lewis 10- by 10-Foot Supersonic Tunnel. The objective was to determine multiaxis control-power characteristics from thrust vectoring. A two-dimensional convergent-divergent nozzle was designed to provide yaw vector angles of 0, -10, and -20 deg combined with geometric pitch vector angles of 0 and 15 deg. Yaw thrust vectoring was provided by yaw flaps located in the nozzle sidewalls. Roll control was obtained from differential pitch vectoring. This investigation was conducted at Mach numbers from 0.20 to 2.47. Angle of attack was varied from 0 to about 19 deg, and nozzle pressure ratio was varied from about 1 (jet off) to 28, depending on Mach number. Increments in force or moment coefficient that result from pitch or yaw thrust vectoring remain essentially constant over the entire angle-of-attack range of all Mach numbers tested. There was no effect of pitch vectoring on the lateral aerodynamic forces and moments and only very small effects of yaw vectoring on the longitudinal aerodynamic forces and moments. This result indicates little cross-coupling of control forces and moments for combined pitch-yaw vectoring
Parametric investigation of single-expansion-ramp nozzles at Mach numbers from 0.60 to 1.20
An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the effects of varying six nozzle geometric parameters on the internal and aeropropulsive performance characteristics of single-expansion-ramp nozzles. This investigation was conducted at Mach numbers from 0.60 to 1.20, nozzle pressure ratios from 1.5 to 12, and angles of attack of 0 deg +/- 6 deg. Maximum aeropropulsive performance at a particular Mach number was highly dependent on the operating nozzle pressure ratio. For example, as the nozzle upper ramp length or angle increased, some nozzles had higher performance at a Mach number of 0.90 because of the nozzle design pressure was the same as the operating pressure ratio. Thus, selection of the various nozzle geometric parameters should be based on the mission requirements of the aircraft. A combination of large upper ramp and large lower flap boattail angles produced greater nozzle drag coefficients at Mach number greater than 0.80, primarily from shock-induced separation on the lower flap of the nozzle. A static conditions, the convergent nozzle had high and nearly constant values of resultant thrust ratio over the entire range of nozzle pressure ratios tested. However, these nozzles had much lower aeropropulsive performance than the convergent-divergent nozzle at Mach number greater than 0.60
Wastewater Reuse
Approximately 1.2 billion people around the world live in areas of physical water scarcity. This could increase to half of the world’s population by 2030 and could displace 24 to 700 million people unless steps are taken to ensure adequate water supply. Water scarcity is an escalating issue within the United States, specifically in Western inland states with arid climates. This scarcity is encouraging communities to investigate tertiary level municipal wastewater treatment, allowing for reuse of wastewater. Unfortunately, wastewater contains numerous contaminants that are not regulated by the Environmental Protection Agency (EPA) under the Safe Drinking Water Act (SDWA). Many of these contaminants are endocrine disrupting compounds (EDCs). According to the European Union Commission, an endocrine disruptor is an exogenous substance that causes adverse health effects in an intact organism, or its progeny, in consequence to the induced changes in endocrine functions. Many EDCs are not completely removed by standard secondary wastewater treatment methods. With the growing demand for potable water, as well as water for irrigation and agricultural purposes, communities are having to evaluate the potential health risks due to EDCs and other unregulated compounds.
The Woo-Pig-Sewage team selected one unregulated contaminant, chlorpyrifos (CLP), to test. CLP is an organophosphate insecticide that is commonly used residentially and commercially. CLP has a long term impact as a cholinesterase inhibitor in humans. Using traditional biological methods, CLP, as well as other pesticides, are nearly impossible to remove. CLP is on the Fourth Unregulated Contaminant Monitoring Rule list produced by the EPA to provide a basis for future regulation. A bench scale unit utilizing ozone treatment (O3), ultraviolet radiation (UV), and granular activated carbon (GAC) was constructed to remove this contaminant from doped nanopure water. Ultimately, the selected technologies will be able to treat secondary wastewater effluent from the wastewater treatment plant (WWTP) in Tucumcari, New Mexico for direct or indirect aquifer reintroduction. Direct aquifer reintroduction would involve injection of water to the existing aquifer, while indirect aquifer introduction would consist of introducing treated effluent to an existing canal system.
An oxidation process paired with UV and GAC filtration can be utilized to remove EDCs such as CLP and other unregulated contaminants from wastewater. O3 is extremely effective at oxidizing bacteria as well as other organic molecules. UV is also a commonly used method to
degrade organic compounds and is currently being used at the WWTP in Tucumcari, New Mexico and in Fayetteville, Arkansas. GAC is utilized to remove trace amounts of contaminants from wastewater streams, usually as a final treatment before the water is reintroduced to the environment. The WWTP in Rio Rancho, New Mexico currently plans to utilize GAC filtration in this manner.
The Woo-Pig-Sewage team performed experiments to determine if the combination of O3, UV, and GAC could reduce CLP to a concentration below the minimum detection limit of 0.001 ppm. To test the effectiveness of the bench scale, caffeine was used as an organic tracer. Bench scale results indicate that the proposed system is effective in the removal of caffeine and CLP from doped water samples. Caffeine concentrations were reduced to below the minimum detection limit of 0.05 ppm for samples with initial concentrations ranging from 0.1 ppm to 10 ppm. CLP was reduced to below the minimum detection limit of 0.001 ppm from and initial concentration of 0.1 ppm.
An industrial scale process was sized based on treating secondary effluent from the WWTP in Tucumcari, NM. The total cost was determined to be an additional 4.95 per 1000 gallons for the existing treatment paired with the proposed system. While this adds a significant cost to the existing treatment at the WWTP in Tucumcari, plants with larger flow rates would see significantly less of an increase in the total cost per 1000 gallons. This can be seen from the comparison of the 144,000 gallon per day (gpd) system with existing UV treatment and the 300,000 gpd Tucumcari system also utilizing UV treatment. The 144,000 gpd system was estimated to cost about 60% more per 1000 gallons. However, if the Tucumcari WWTP is awarded a grant to cover 100% of the Fixed Capital Investment (FCI), the proposed system would only increase the cost per 1000 gallons by 38%. If the EPA determines that EDCs such as CLP must be removed from the effluent of WWTPs, a process such as the one proposed by the Woo-Pig-Sewage team will be necessary
Aerodynamic Characteristics of a Supersonic Fighter Aircraft Model at Mach 0.40 to 2.47
The aerodynamic characteristics of an advanced twin-engine fighter aircraft designed for supersonic cruise have been studied in the Langley 16-Foot Transonic Tunnel and the Lewis 10- by 10-Foot Supersonic Tunnel. The objective of this investigation was to establish an aerodynamic data base for the configuration with flow-through nacelles and representative inlets. The use of a canard for trim and the effects of fairing over the inlets were assessed. Comparisons between experimental and theoretical results were also made. The theoretical results were determined by using a potential vortex lift code for subsonic speeds and a linear aerodynamic code for supersonic speeds. This investigation was conducted at Mach numbers from 0.40 to 2.47, at angles of attack from 0 deg to about 20 deg, and at inlet capture ratios of about 0.5 to 1.4
Effect of simulated in-flight thrust reversing on vertical-tail loads of F-18 and F-15 airplane models
Investigations were conducted in the Langley 16-Foot Transonic Tunnel to provide data on a 0.10-scale model of the prototype F-18 airplane and a 0.047-scale model of the F-15 three-surface configuration (canard, wing, and horizontal tails). Test data were obtained at static conditions and at Mach numbers from 0.6 to 1.2 over an angle-of-attack range from 2 deg to 15 deg. Nozzle pressure ratio was varied from jet off to about 8.0
Building Capacity in Nonprofit Organizations
Offers a capacity building model that is based on a review of civil society, sustainable development, and organizational management literature. Reviews effective capacity building programs sponsored or operated by foundations. Includes recommendations
Integration and visualization of systems biology data in context of the genome
<p>Abstract</p> <p>Background</p> <p>High-density tiling arrays and new sequencing technologies are generating rapidly increasing volumes of transcriptome and protein-DNA interaction data. Visualization and exploration of this data is critical to understanding the regulatory logic encoded in the genome by which the cell dynamically affects its physiology and interacts with its environment.</p> <p>Results</p> <p>The Gaggle Genome Browser is a cross-platform desktop program for interactively visualizing high-throughput data in the context of the genome. Important features include dynamic panning and zooming, keyword search and open interoperability through the Gaggle framework. Users may bookmark locations on the genome with descriptive annotations and share these bookmarks with other users. The program handles large sets of user-generated data using an in-process database and leverages the facilities of SQL and the R environment for importing and manipulating data.</p> <p>A key aspect of the Gaggle Genome Browser is interoperability. By connecting to the Gaggle framework, the genome browser joins a suite of interconnected bioinformatics tools for analysis and visualization with connectivity to major public repositories of sequences, interactions and pathways. To this flexible environment for exploring and combining data, the Gaggle Genome Browser adds the ability to visualize diverse types of data in relation to its coordinates on the genome.</p> <p>Conclusions</p> <p>Genomic coordinates function as a common key by which disparate biological data types can be related to one another. In the Gaggle Genome Browser, heterogeneous data are joined by their location on the genome to create information-rich visualizations yielding insight into genome organization, transcription and its regulation and, ultimately, a better understanding of the mechanisms that enable the cell to dynamically respond to its environment.</p
Active microwave users working group program planning
A detailed programmatic and technical development plan for active microwave technology was examined in each of four user activities: (1) vegetation; (2) water resources and geologic applications, and (4) oceanographic applications. Major application areas were identified, and the impact of each application area in terms of social and economic gains were evaluated. The present state of knowledge of the applicability of active microwave remote sensing to each application area was summarized and its role relative to other remote sensing devices was examined. The analysis and data acquisition techniques needed to resolve the effects of interference factors were reviewed to establish an operational capability in each application area. Flow charts of accomplished and required activities in each application area that lead to operational capability were structured
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