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1

Nuclear air cushion vehicles  

NASA Technical Reports Server (NTRS)

The state-of-the-art of the still-conceptual nuclear air cushion vehicle, particularly the nuclear powerplant is identified. Using mission studies and cost estimates, some of the advantages of nuclear power for large air cushion vehicles are described. The technology studies on mobile nuclear powerplants and conceptual ACV systems/missions studies are summarized.

Anderson, J. L.

1973-01-01

2

Air cushion vehicles: A briefing  

NASA Technical Reports Server (NTRS)

Experience and characteristics; the powering, uses, and implications of large air cushion vehicles (ACV); and the conceptual design and operation of a nuclear powered ACV freighter and supporting facilities are described.

Anderson, J. L.; Finnegan, P. M.

1971-01-01

3

Analog analysis of a tracked air-cushion vehicle.  

NASA Technical Reports Server (NTRS)

The dynamics of tracked air-cushion vehicles considered for high-speed ground transportation systems are examined using a vehicle model represented by a one-degree-of-freedom system. The respective equations of motion are derived, and the control system is discussed. The equations obtained for the cushion are solved using an analog computer. The computer showed the effect of the control technique on the relative motion between vehicle and guideway.

Leatherwood, J. D.

1972-01-01

4

Northwest passage: Trade route for large air cushion vehicles  

NASA Technical Reports Server (NTRS)

A conceptual vehicle and powerplant (10,000-ton) nuclear-powered air-cushion vehicle (ACV) that could open the Northwest Passage and other Arctic passages to commercial traffic is identified. The report contains a description of the conceptual vehicle, including the powerplant and operations, an assessment of technical feasibility, estimates of capital and operating costs, and identification of eligible cargo and markets. A comparison of the nuclear ACV freighter with nuclear container ships shows that for containerized or roll-on/roll-off cargo the ACV would provide greatly reduced transit time between North Atlantic and North Pacific ports at a competitive cost.

Anderson, J. L.

1973-01-01

5

Load distribution control system design for a semi-track air-cushion vehicle  

Microsoft Academic Search

This paper describes the design principle for a semi-track air-cushion vehicle working on soft terrain. A novel structure, i.e., a flexible joint mechanism is designed for the semi-track air-cushion vehicle suspension system. Focusing on optimizing the total power consumption of the vehicle, three main issues were studied in this paper. First, a theoretical model for minimizing the total power demand

Zhe Luo; Fan Yu

2007-01-01

6

Air cushion landing system  

NASA Technical Reports Server (NTRS)

Static and dynamic performance of air cushion landing system is simulated in computer program that treats four primary ACLS subsystems: fan, feeding system, trunk, and cushion. Configuration of systems is sufficiently general to represent variety of practical designs.

Boghami, K. M.; Captain, K. M.; Fish, R. B.

1978-01-01

7

Finger materials for air cushion vehicles. Volume 2: Base fabrics for finger materials  

NASA Astrophysics Data System (ADS)

Since the short lifetimes of seal/skirt systems on surface effect vehicles (SEV's) severely limit the long-term serviceability on such craft, a systematic study was undertaken to evaluate the effects of fabric structure on the performance of rubber/fabric skirt materials under conditions of high speed, high-curvature flexing. A series of nylon fabrics was designed and manufactured in which the fiber denier, yarn denier, yarn twist, yarn crimp, weave pattern and float length were varied, but in which the tensile strength was kept constant throughout. Each one of the fabrics was rubber-coated using the same natural rubber/polybutadiene blend and the same coating technique. A flex-testing apparatus was designed and built for flexing the rubber/fabric composite materials in air at an average radius of curvature of 0.28 in. at a cycling frequency of 15 Hz. The lifetimes in flex of the experimental series of fabrics, as indicated by the appearance of flex cracks in the rubber layer, ranged from a low of 140,000 cycles to a high of 21.7 million cycles, a range of over two orders of magnitude. Factorial analysis of the test results showed that lower yarn denier, lower yarn crimp, and shorter float length (plain weave) in the fabric substrate offer significant advantages in the ability of the fabric to withstand flexing. Design of three broad fabrics for full-scale skirt trials on the SRN4 craft is described.

Schoppee, M. M.; Skelton, J.; Toney, M. M.; Klemens, W.

1984-12-01

8

Wave effects on large floating structures with air cushions  

Microsoft Academic Search

An analysis is made of a VLFS which is partially supported by an air cushion. The interface between the air cushion and the water is considered to be a free surface. The elevation of this surface is represented by an appropriate set of Fourier generalized modes, and extended equations of motion are derived for the rigid-body motions and generalized modes.

C.-H. Lee; J. N. Newman

2000-01-01

9

Air cushion landing gear applications study  

NASA Technical Reports Server (NTRS)

A series of air cushion landing gear (ACLG) applications was studied and potential benefits analyzed in order to identify the most attractive of these. The selected applications are new integrated designs (not retrofits) and employ a modified design approach with improved characteristics and performance. To aid the study, a survey of potential users was made. Applications were evaluated in the light of comments received. A technology scenario is developed, with discussion of problem areas, current technology level and future needs. Feasible development timetables are suggested. It is concluded that near-term development of small-size ACLG trunks, exploration of flight effects and braking are key items. The most attractive applications are amphibious with very large cargo aircraft and small general aviation having the greatest potential.

Earl, T. D.

1979-01-01

10

Air-cushion tankers for Alaskan North Slope oil  

NASA Technical Reports Server (NTRS)

A concept is described for transporting oil from the Arctic to southern markets in 10,000-ton, chemically fueled air-cushion vehicles (ACV's) configured as tankers. Based on preliminary cost estimates the conceptual ACV tanker system as tailored to the transportation of Alaskan North Slope oil could deliver the oil for about the same price per barrel as the proposed trans-Alaska pipeline with only one-third of the capital investment. The report includes the description of the conceptual system and its operation; preliminary cost estimates; an appraisal of ACV tanker development; and a comparison of system costs, versatility, vulnerability, and ecological effect with those of the trans-Alaska pipeline.

Anderson, J. L.

1973-01-01

11

Experimental and analytical studies of advanced air cushion landing systems  

NASA Technical Reports Server (NTRS)

Several concepts are developed for air cushion landing systems (ACLS) which have the potential for improving performance characteristics (roll stiffness, heave damping, and trunk flutter), and reducing fabrication cost and complexity. After an initial screening, the following five concepts were evaluated in detail: damped trunk, filled trunk, compartmented trunk, segmented trunk, and roll feedback control. The evaluation was based on tests performed on scale models. An ACLS dynamic simulation developed earlier is updated so that it can be used to predict the performance of full-scale ACLS incorporating these refinements. The simulation was validated through scale-model tests. A full-scale ACLS based on the segmented trunk concept was fabricated and installed on the NASA ACLS test vehicle, where it is used to support advanced system development. A geometrically-scaled model (one third full scale) of the NASA test vehicle was fabricated and tested. This model, evaluated by means of a series of static and dynamic tests, is used to investigate scaling relationships between reduced and full-scale models. The analytical model developed earlier is applied to simulate both the one third scale and the full scale response.

Lee, E. G. S.; Boghani, A. B.; Captain, K. M.; Rutishauser, H. J.; Farley, H. L.; Fish, R. B.; Jeffcoat, R. L.

1981-01-01

12

Reduced energy and volume air pump for a seat cushion  

DOEpatents

An efficient pump system is described for transferring air between sets of bladders in a cushion. The pump system utilizes a reversible piston within a cylinder in conjunction with an equalizing valve in the piston which opens when the piston reaches the end of travel in one direction. The weight of a seated user then forces air back across the piston from an inflated bladder to the previously deflated bladder until the pressure is equalized. In this fashion the work done by the pump is cut in half. The inflation and deflation of the different bladders is controlled to vary the pressure on the several pressure points of a seated user. A principal application is for wheel chair use to prevent pressure ulcers. 12 figs.

Vaughn, M.R.; Constantineau, E.J.; Groves, G.E.

1997-08-19

13

Reduced energy and volume air pump for a seat cushion  

DOEpatents

An efficient pump system for transferring air between sets of bladders in a cushion. The pump system utilizes a reversible piston within a cylinder in conjunction with an equalizing valve in the piston which opens when the piston reaches the end of travel in one direction. The weight of a seated user then forces air back across the piston from an inflated bladder to the previously deflated bladder until the pressure is equalized. In this fashion the work done by the pump is cut in half. The inflation and deflation of the different bladders is controlled to vary the pressure on the several pressure points of a seated user. A principal application is for wheel chair use to prevent pressure ulcers.

Vaughn, Mark R. (Albuquerque, NM); Constantineau, Edward J. (Albuquerque, NM); Groves, Gordon E. (Tijeras, NM)

1997-01-01

14

Human volunteer and anthropomorphic dummy tests of driver air cushion system.  

PubMed

The dynamic impact tests at Southwest Research Institute for the first time exposed human volunteers to production-like driver air cushion system depolyments at impact levels equivalent to a 30 mph barrier crash (48 kph). No significant injury was produced. At no time was it necessary for the secondary restraint systems to be utilized and the entire program schedule was carried out as planned. All tests were conducted under the most safe and controlled conditions possible, and typify only what the air cushions might accomplish in direct, head-on impacts up to 30 mph (48 kph). In comparing the test results, the anthropomorphic dummies' response to impact was conservative compared to the human volunteers. These and other human volunteer tests were run to help understand what might be expected in real world driving conditions. To further understand the value of this new safety system, 1000 1973 Chevrolets were built and places in a high mileage fleet across the couhtry. They now have accumulated 41 millions miles of experience and have had 15 accidents of sufficient severity that the air cushion depolyed. This fleet was followed with 1974 vehicles with air cushions sold to the general public as an option. These cars, combined with the test fleet, have accumulated approximately 60 million miles and have a total of 25 depolyments with 34 occupants in the front seat. There has been one fatality in accidents involving these vehicles, a seven week old baby boy. The child was not restrained in any protective carrier. All other injuries have been classified AIS-1 except for three AIS-2. Facial injuries have been very minimal and there have been no known hearing impairments as a result of these accident situations. To date, the results have been encouraging but caution must be taken in their interpretation. The population of drivers is not to be considered normal. The 60 million miles may appear to be a large number, but only represents 25 minutes of driving time of the total U.S. car population in 1 year. PMID:1116324

Smith, G R; Gulash, E C; Baker, R G

1975-01-01

15

Green vehicle shock absorber: Micromachined wavy shaped piezoelectric cushion energy harvester and its power generating demonstration based on real navigation  

Microsoft Academic Search

The paper presents a novel micromachined piezoelectric cushion power generator which harvests vibration energy from the vehicle shock absorber. The developed transducer demonstrates the feasibility of the concept of Green vehicle shock absorber. Two major components are involved in implementation of the device: a wavy shaped PVDF film for scavenging vibration energy and an elastic PDMS cushion for damping the

Guo-Hua Feng; Min-Yiang Tsai

2011-01-01

16

Effect of a Dynamic Air Cushion on the Development of Leg Edema during Wheelchair Sitting  

PubMed Central

[Purpose] To clarify how a novel dynamic cushion affects the leg edema evoked by wheelchair sitting, we measured the changes in leg volume induced during wheelchair sitting with the dynamic air cushion or a static cushion. [Subjects and Methods] Nine healthy male subjects participated in this study. Leg edema during wheelchair sitting was evaluated with strain gauge plethysmography (the gauge was placed around the middle portion of the lower thigh). Following a period of rest, each subject was asked to sit on a wheelchair containing the dynamic cushion for 15?min. Then, the protocol was repeated with a static cushion. The angles of the knee and ankle joints were set to 90 degrees, and no footrests were used. [Results] The change in leg volume observed during sitting on the dynamic cushion (0.00 ± 0.03?mL/100?mL) was smaller than that observed during sitting on the static cushion (0.02 ± 0.02?mL/100?mL). [Conclusion] These results suggested that the dynamic cushion relieved leg edema during wheelchair sitting. PMID:25013295

Murata, Jun; Murata, Shin; Ohyama, Michie; Kogo, Haruki; Matsubara, Shohzo

2014-01-01

17

Effect of a Dynamic Air Cushion on the Development of Leg Edema during Wheelchair Sitting.  

PubMed

[Purpose] To clarify how a novel dynamic cushion affects the leg edema evoked by wheelchair sitting, we measured the changes in leg volume induced during wheelchair sitting with the dynamic air cushion or a static cushion. [Subjects and Methods] Nine healthy male subjects participated in this study. Leg edema during wheelchair sitting was evaluated with strain gauge plethysmography (the gauge was placed around the middle portion of the lower thigh). Following a period of rest, each subject was asked to sit on a wheelchair containing the dynamic cushion for 15?min. Then, the protocol was repeated with a static cushion. The angles of the knee and ankle joints were set to 90 degrees, and no footrests were used. [Results] The change in leg volume observed during sitting on the dynamic cushion (0.00 ± 0.03?mL/100?mL) was smaller than that observed during sitting on the static cushion (0.02 ± 0.02?mL/100?mL). [Conclusion] These results suggested that the dynamic cushion relieved leg edema during wheelchair sitting. PMID:25013295

Murata, Jun; Murata, Shin; Ohyama, Michie; Kogo, Haruki; Matsubara, Shohzo

2014-06-01

18

Characteristics of an Air Cushion Landing System incorporating an inelastic trunk  

NASA Technical Reports Server (NTRS)

A series of static and dynamic tests performed on an Air Cushion Landing System (ACLS) incorporating inelastic trunk are described. The tests were performed on an apparatus which had provisions to isolate heave-pitch and roll motion on the prototype cushion. The results of the test show that the sides of the trunk behave differently from the trunk ends. The tests also demonstrate that the current ACLS designs suffer from low heave damping, low roll stiffness and fan stall problems.

Boghani, A. B.; Captain, K. M.; Wormley, D. N.

1978-01-01

19

Research of air-cushion isolation effects on high arch dam reservoir  

NASA Astrophysics Data System (ADS)

A three-dimensional (3D) finite element model of air-cushion isolated arch dam is presented with the nonlinear gas-liquid-solid multi-field dynamic coupling effect taken into account. In this model, the displacement formulation in Lagrange method, pressure formulation in Euler method, nonlinear contact model based on Coulomb friction law are applied to the air-cushion, reservoir and contraction joint domain, respectively. The dynamic response of Jinping I arch dam with a height of 305 m is analyzed using the seismic records of the Wenchuan Earthquake in 2008. Numerical results show that the air-cushion isolation reduces significantly the hydrodynamic pressure as well as the opening width for the contraction joints of high arch dam.

Zhang, Shao-Jie; Chen, Jiang; Zhang, Yuan-Ze; Liu, Hao-Wu

2011-10-01

20

Speed control with end cushion for high speed air cylinder  

DOEpatents

A high speed air cylinder in which the longitudinal movement of the piston within the air cylinder tube is controlled by pressurizing the air cylinder tube on the accelerating side of the piston and releasing pressure at a controlled rate on the decelerating side of the piston. The invention also includes a method for determining the pressure required on both the accelerating and decelerating sides of the piston to move the piston with a given load through a predetermined distance at the desired velocity, bringing the piston to rest safely without piston bounce at the end of its complete stroke.

Stevens, Wayne W. (Idaho Falls, ID); Solbrig, Charles W. (Idaho Falls, ID)

1991-01-01

21

Air lifted and propelled vehicle  

SciTech Connect

This patent describes a vehicle which rides on air cushion and which is propelled by air, comprising: upper deck means, having a bottom edge which defines the periphery of an area; a thin, flexible sheet located below the upper deck means, extending beneath the bottom edge and secured beneath the bottom edge for defining a plenum that is defined by and closed off by the upper deck means and the sheet. The deck means is shaped within the area defined by its bottom edge for causing the plenum to always be an open space and the upper deck means is rigid enough to maintain that open condition of the plenum; the sheet being secured in a manner permitting the sheet to pillow when air is pressurized in the plenum; and the sheet being perforated below the upper deck means for permitting exit of air from the plenum at a controllable rate through the perforations; the sheet having a large plurality of the perforations dispersed over most of its area below the upper deck means; each of the perforations being a hole.

Jones, T.E.; Johnson, R.A.

1987-02-17

22

Numerical simulation of the flow in a conduit, in the presence of a confined air cushion  

NASA Astrophysics Data System (ADS)

A rectangular conduit with a closed end has water flowing in/out at the other end. The water level at the open end has an imposed sinusoidal movement. When this level is higher than the ceiling of the conduit, a certain mass of air is trapped under the ceiling. In a previous article (T.D. Nguyen, La Houille Blanche, No. 2, 1990), it was supposed that this air is flowing out freely through the ceiling, so the relative pressure at the water surface is zero, and the water hammer at the dead end of the conduit was calculated when the conduit was thoroughly filled. In this article, it is supposed that the trapped air is compressed isothermally or adiabatically. The set of equations is resolved (water continuity and movement equations, air state equation) by supposing a regime of flow at each section (section submerged or not), a certain value for the air pressure and by using the sweep method to determine the water flow characteristics. The air volume calculated by iteration must converge, and the calculated regimes at each section (submerged or free) must agree with the supposed regimes. The simulation is performed first with a horizontal conduit then with an inclined conduit. As expected, adiabatic compression gives higher pressure than isothermal compression. The simulation shows also that when there is an air cushion, compared with the case when air is flowing out freely, the shock of the water hammer at the closed end of the conduit is significantly reduced. This method is aimed at calculating the flow with entrapped air in the inlet/outlet tunnel of a hydroelectric plant, or in sewer system pipe when a sudden discharge surge (due to turbin opening/closing or to urban storm) changes a previously free-surface flow in a mostly full-pipe flow, but with some air entrapped under the ceiling. Copyright

Nguyen, Trieu Dong

1999-02-01

23

Study on the stability of waterpower-speed control system for hydropower station with air cushion surge chamber  

NASA Astrophysics Data System (ADS)

According to the fact that the effects of penstock, unit and governor on stability of water level fluctuation for hydropower station with air cushion surge chamber are neglected in previous researches, in this paper, Thoma assumption is broken through, the complete mathematical model of waterpower-speed control system for hydropower station with air cushion surge chamber is established, and the comprehensive transfer function and linear homogeneous differential equation that characterize the dynamic characteristics of system are derived. The stability domain that characterizes the good or bad of stability quantitatively is drawn by using the stability conditions. The effects of the fluid inertia in water diversion system, the air cushion surge chamber parameters, hydraulic turbine characteristics, generator characteristics, and regulation modes of governor on the stability of waterpower-speed control system are analyzed through stability domain. The main conclusions are as follows: The fluid inertia in water diversion system and hydraulic turbine characteristics have unfavorable effects on the system while generator characteristics have favorable effect. The stability keeps getting better with the increase of chamber height and basal area and the decrease of air pressure and air polytropic exponent. The stability of power regulation mode is obviously better than that of frequency regulation mode.

Guo, W. C.; Yang, J. D.; Chen, J. P.; Teng, Y.

2014-12-01

24

Modeling, simulation & optimization of the landing craft air cushion fleet readiness.  

SciTech Connect

The Landing Craft Air Cushion is a high-speed, over-the-beach, fully amphibious landing craft capable of carrying a 60-75 ton payload. The LCAC fleet can serve to transport weapons systems, equipment, cargo and personnel from ship to shore and across the beach. This transport system is an integral part of our military arsenal and, as such, its readiness is an important consideration for our national security. Further, the best way to expend financial resources that have been allocated to maintain this fleet is a critical Issue. There is a clear coupling between the measure of Fleet Readiness as defined by the customer for this project and the information that is provided by Sandia's ProOpta methodology. Further, there is a richness in the data that provides even more value to the analyst. This report provides an analytic framework for understanding the connection between Fleet Readiness and the output provided by Sandia's ProOpta software. Further, this report highlights valuable information that can also be made available using the ProOpta output and concepts from basic probability theory. Finally, enabling assumptions along with areas that warrant consideration for further study are identified.

Engi, Dennis

2006-10-01

25

A Comparative Study Between an Improved Novel Air-Cushion Sensor and a Wheeled Probe for Minimally Invasive Surgery  

PubMed Central

Abstract Purpose We describe a comparative study between an enhanced air-cushion tactile sensor and a wheeled indentation probe. These laparoscopic tools are designed to rapidly locate soft-tissue abnormalities during minimally invasive surgery (MIS). Materials and Methods The air-cushion tactile sensor consists of an optically based sensor with a 7.8?mm sphere “floating” on a cushion of air at the tip of a shaft. The wheeled indentation probe is a 10?mm wide and 5?mm in diameter wheel mounted to a force/torque sensor. A continuous rolling indentation technique is used to pass the sensors over the soft-tissue surfaces. The variations in stiffness of the viscoelastic materials that are detected during the rolling indentations are illustrated by stiffness maps that can be used for tissue diagnosis. The probes were tested by having to detect four embedded nodules in a silicone phantom. Each probe was attached to a robotic manipulator and rolled over the silicone phantom in parallel paths. The readings of each probe collected during the process of rolling indentation were used to achieve the final results. Results The results show that both sensors reliably detected the areas of variable stiffness by accurately identifying the location of each nodule. These are illustrated in the form of two three-dimensional spatiomechanical maps. Conclusions These probes have the potential to be used in MIS because they could provide surgeons with information on the mechanical properties of soft tissue, consequently enhancing the reduction in haptic feedback. PMID:20624084

Challacombe, Benjamin; Li, Jichun; Seneviratne, Lakmal; Althoefer, Kaspar; Dasgupta, Prokar; Murphy, Declan

2010-01-01

26

Landing performance of an air cushion landing system installed on a 1/10-scale dynamic model on the C-8 Buffalo airplane  

NASA Technical Reports Server (NTRS)

An experimental study was conducted to evaluate the landing behavior of a 1/10-scale dynamic model of the C-8 Buffalo airplane equipped with an air-cushion landing system (ACLS) on a variety of surfaces including both calm and rough water and a smooth hard surface. Taxi runs were made on the hard surface over several obstacles. Landings were made with the model at various pitch and roll attitudes and vertical velocities and at one nominal horizontal velocity. Data from the landings include time histories of the trunk and air-cushion pressures and accelerations at selected locations on the model.

Thompson, W. C.

1973-01-01

27

Landing impact studies of a 0.3-scale model air cushion landing system for a Navy fighter airplane  

NASA Technical Reports Server (NTRS)

An experimental study was conducted in order to determine the landing-impact behavior of a 0.3-scale, dynamically (but not physically) similar model of a high-density Navy fighter equipped with an air cushion landing system. The model was tested over a range of landing contact attitudes at high forward speeds and sink rates on a specialized test fixture at the Langley aircraft landing loads and traction facility. The investigation indicated that vertical acceleration at landing impact was highly dependent on the pitch angle at ground contact, the higher acceleration of approximately 5g occurring near zero body-pitch attitude. A limited number of low-speed taxi tests were made in order to determine model stability characteristics. The model was found to have good pitch-damping characteristics but stability in roll was marginal.

Leland, T. J. W.; Thompson, W. C.

1975-01-01

28

Experimental and analytical dynamic flow characteristics of an axial-flow fan from an air cushion landing system model  

NASA Technical Reports Server (NTRS)

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.

Thompson, W. C.; Boghani, A. B.; Leland, T. J. W.

1977-01-01

29

Foam Cushioning  

NASA Technical Reports Server (NTRS)

One innovation developed by a contractor at Ames Research Center was an open cell polymeric foam material with unusual properties. Intended as padding for aircraft seats the material offered better impact protection against accidents, and also enhanced passenger comfort because it distributed body weight evenly over the entire contact area. Called a slow springback foam, it flows to match the contour of the body pressing against it, and returns to its original shape once the pressure is removed. It has many applications including aircraft cushions and padding, dental stools, and athletic equipment. Now it's used by Dynamic Systems, Inc. for medical applications such as wheel chairs for severely disabled people which allow them to sit for 3-8 hours where they used to be uncomfortable in 15-30 minutes.

1988-01-01

30

Insect powered micro air vehicles  

Microsoft Academic Search

In this paper we present successful navigation of a mechanically linked insect moth-pair, using light-weight and low-power actuators, demonstrating insect powered micro air vehicles (MAVs). These MAVs can fly for long periods of time, consuming only a small fraction(1%) of power compared to purely mechanical MAVs. We demonstrate strategies for harnessing the high energy-density biofuel and high efficiency muscle actuators

Siva Pulla; Amit Lal

2009-01-01

31

System safety engineering in the development of advanced surface transportation vehicles  

NASA Technical Reports Server (NTRS)

Applications of system safety engineering to the development of advanced surface transportation vehicles are described. As a pertinent example, the paper describes a safety engineering efforts tailored to the particular design and test requirements of the Tracked Air Cushion Research Vehicle (TACRV). The test results obtained from this unique research vehicle provide significant design data directly applicable to the development of future tracked air cushion vehicles that will carry passengers in comfort and safety at speeds up to 300 miles per hour.

Arnzen, H. E.

1971-01-01

32

A New Aerodynamic Traction Principle for Handling Products on an Air Cushion  

E-print Network

sheets, solar cell or flat foodstuffs. The handling of delicate, freshly painted, hot, sensitive is held on a plate which is drilled by many small holes. Pressurized air flows upwards through these holes

Paris-Sud XI, Université de

33

Persistent Surveillance Using Multiple Unmanned Air Vehicles  

E-print Network

require long endurance and unmanned aerial vehicles are a natural choice for the sensing platforms1 Persistent Surveillance Using Multiple Unmanned Air Vehicles Nikhil Nigam and Ilan Kroo. These are tested in a multiple unmanned air vehicle (UAV) simulation environment, developed for this program

Stanford University

34

Intelligence Applied to Air Vehicles  

NASA Technical Reports Server (NTRS)

The exponential growth in information technology has provided the potential for air vehicle capabilities that were previously unavailable to mission and vehicle designers. The increasing capabilities of computer hardware and software, including new developments such as neural networks, provide a new balance of work between humans and machines. This paper will describe several NASA projects, and review results and conclusions from ground and flight investigations where vehicle intelligence was developed and applied to aeronautical and space systems. In the first example, flight results from a neural network flight control demonstration will be reviewed. Using, a highly-modified F-15 aircraft, a NASA/Dryden experimental flight test program has demonstrated how the neural network software can correctly identify and respond to changes in aircraft stability and control characteristics. Using its on-line learning capability, the neural net software would identify that something in the vehicle has changed, then reconfigure the flight control computer system to adapt to those changes. The results of the Remote Agent software project will be presented. This capability will reduce the cost of future spacecraft operations as computers become "thinking" partners along with humans. In addition, the paper will describe the objectives and plans for the autonomous airplane program and the autonomous rotorcraft project. Technologies will also be developed.

Rosen, Robert; Gross, Anthony R.; Fletcher, L. Skip; Zornetzer, Steven (Technical Monitor)

2000-01-01

35

Visual inspections of wheelchair cushions after everyday use.  

PubMed

The objective of this project was to document the state of wheelchair cushions after everyday use by identifying signs of wear, fatigue, and failure. Visual inspection was done on 202 wheelchair cushions with average and median ages of 2.7 and 2 years, respectively. Most cushions were deemed to be "clean" and the proportion did not change across age groups. A high proportion of cushion covers showed signs of wear with damage to fabric and seams being most prevalent. Foam cushions showed more signs of wear than viscous fluid or air cushions. More than 60% of foam cushions showed signs of permanent deformation, and in nearly half, the foam exhibited granulation or brittleness. About 15% of the bladders used in viscous fluid or air cushions exhibited cracks or breaks in the material. In conclusion, a visual inspection of wheelchair cushions showed that most cushions appeared clean and were in good repair over a wide range of ages and usage patterns. While documenting signs of wear after use can help inform interventions and monitoring, research is needed to document changes in performance of wheelchair cushions overtime as a means to develop better replacement strategies. PMID:24020156

Sprigle, Stephen

2013-01-01

36

Aerodynamics for Revolutionary Air Vehicles  

NASA Technical Reports Server (NTRS)

Aeronautics research has seriously declined partly because of the perception that it is a mature science and only incremental improvements are possible. Recent aeronautics roadmapping activities at NASA Langley paint a different picture of the future. Breakthroughs are still felt to be possible if we expand the current design space of today's vehicles and optimize the airspace and vehicles as a system. The paper describes some of the challenges that the aircraft and airline industry face. These challenges include political, technical and environmental issues. Examples of the opportunities and technologies that could provide a different vision for the future are discussed.

Sellers, William L., III; Singer, Bart A.; Leavitt, Laurence D.

2003-01-01

37

Highway Crash Cushions  

E-print Network

available: 1. the Modular Crash Cushion, 2. the HI-DRO Cushion, 3. the Fitch Inertial Barrier, and 4. the TOR-SHOK Barrier. Presented herein is a "state-of-the-art" report concerning these four devices. The main subj ect is the Modular Crash Cushion... Inertial Barrier; and the description, theory, and limited testing and field experi- ence with the TOR-SHOK Barrier. iv ACKNOWLEDGMENTS The author wishes to express his sincere appreciation to the following individuals and organizations who made...

White, Monroe Carlton

1971-01-01

38

Toxicity of parked motor vehicle indoor air.  

PubMed

The interior of motor vehicles is made of a wide variety of synthetic materials, which emit volatile organic compounds (VOC). We tested the health effects of emissions from vehicles exposed to "parked in sunshine" conditions. A new and a 3 year old vehicle with identical interior were exposed to 14 000 W of light. Indoor air was analyzed by GC-MS. Toxicity of extracts of indoor air was assayed in human primary keratinocytes, human lung epithelial A549 cell line, and Chinese hamster V79 lung fibroblasts. In addition, toxicity after metabolic activation by CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, and CYP2E1 was assayed. The effect on type I allergic reaction (IgE-mediated immune response), type IV allergic reaction (T-cell mediated immune response), and irritative potential was evaluated also. A total of 10.9 and 1.2 mg/m(3) VOC were found in new and used motor vehicle indoor air, respectively. The major compounds in the new vehicle were o,m,p-xylenes, C3 and C4-alkylbenzenes, dodecane, tridecane, and methylpyrrolidinone. In the used vehicle they were acetone, methylpyrrolidinone, methylcyclohexane, acetaldehyde, o,m,p-xylenes, ethylhexanol, and toluene. No toxicity was observed in any cell line with or without metabolic activation. Neither did we find an effect on type IV sensitization or an irritative potential. A slight but statistically significant aggravating effect on IgE-mediated immune response of only the new vehicle indoor air was determined (p < 0.05). The IgE-response modulating effect of indoor air might be relevant for atopic individuals. Else no direct toxicity, no toxicity after metabolic activation by cytochrome P450, and no irritative or type IV sensitizing potential of motor vehicle indoor air were found, neither from the new nor used vehicle. Our investigations indicated no apparent health hazard of parked motor vehicle indoor air. PMID:17438825

Buters, Jeroen T M; Schober, Wolfgang; Gutermuth, Jan; Jakob, Thilo; Aguilar-Pimentel, Antonio; Huss-Marp, Johannes; Traidl-Hoffmann, Claudia; Mair, Sabine; Mair, Stefan; Mayer, Florian; Breuer, Klaus; Behrendt, Heidrun

2007-04-01

39

Flexible-Wing-Based Micro Air Vehicles  

NASA Technical Reports Server (NTRS)

This paper documents the development and evaluation of an original flexible-wing-based Micro Air Vehicle (MAV) technology that reduces adverse effects of gusty wind conditions and unsteady aerodynamics, exhibits desirable flight stability, and enhances structural durability. The flexible wing concept has been demonstrated on aircraft with wingspans ranging from 18 inches to 5 inches. Salient features of the flexible-wing-based MAV, including the vehicle concept, flexible wing design, novel fabrication methods, aerodynamic assessment, and flight data analysis are presented.

Ifju, Peter G.; Jenkins, David A.; Ettinger, Scott; Lian, Yong-Sheng; Shyy, Wei; Waszak, Martin R.

2002-01-01

40

Covert air vehicle 2003 LDRD final report.  

SciTech Connect

This report describes the technical work carried out under a 2003 Laboratory Directed Research and Development project to develop a covert air vehicle. A mesoscale air vehicle that mimics a bird offers exceptional mobility and the possibility of remaining undetected during flight. Although some such vehicles exist, they are lacking in key areas: unassisted landing and launching, true mimicry of bird flight to remain covert, and a flapping flight time of any real duration. Current mainstream technology does not have the energy or power density necessary to achieve bird like flight for any meaningful length of time; however, Sandia has unique combustion powered linear actuators with the unprecedented high energy and power density needed for bird like flight. The small-scale, high-pressure valves and small-scale ignition to make this work have been developed at Sandia. We will study the feasibility of using this to achieve vehicle takeoff and wing flapping for sustained flight. This type of vehicle has broad applications for reconnaissance and communications networks, and could prove invaluable for military and intelligence operations throughout the world. Initial tests were conducted on scaled versions of the combustion-powered linear actuator. The tests results showed that heat transfer and friction effects dominate the combustion process at 'bird-like' sizes. The problems associated with micro-combustion must be solved before a true bird-like ornithopter can be developed.

Spletzer, Barry Louis; Callow, Diane Schafer; Salton, Jonathan Robert; Fischer, Gary John

2003-11-01

41

Vehicle overturning vulnerability from air blast loads  

NASA Astrophysics Data System (ADS)

The overturning response of an armored personnel carrier to air blast loads derived from a nuclear blast environment is presented. The orientation of the vehicle is side-on to the air blast shock front. It is assumed there is no translation at the downwind wheels, i.e., the roll over point. In addition, the vehicle is assumed to behave as a rigid body. That is, the suspension system are taken as rigid, so that the wheels and axles rotate in unison with the body. It can be shown that this assumption slightly overestimates the overturning resistance of vehicles with suspension systems. For a stiff suspension system, such as that of the APC, the rigid body behavior assumption is justified. The only motion possible for this analysis is rotation about the rollover point. The effect of overturning restraint systems has been included in the analysis by incorporating a perfectly plastic vehicle to ground connection on the upwind side of the vehicle. The results give the threshold nuclear environment that just causes overturning. The threshold environment is given in terms of a peak overpressure corresponding to a weapon yield. Results are presented for a range of weapon yields from 1KT to 1MT.

Robinson, R. R.; Napadensky, H.; Longinow, A.

1984-08-01

42

Ventilation control for improved cabin air quality and vehicle safety  

Microsoft Academic Search

Motor vehicles are a prime pollution source. In certain circumstances, the vehicle's exhaust may enter the vehicle cabin causing driver discomfort and adverse health effects. As a result, driver reflexes decrease and fatigue may be exhibited. Oxygen depletion due to vehicle occupant breathing can also threaten vehicle safety. Cabin air filters and ventilation control are capable of improving passenger comfort,

Kosmas Galatsis; W. Wlodarski; Yongxiang Li; K. Kalantar-zadeh

2001-01-01

43

Characterization of volatile organic chemical emissions from carpet cushions  

SciTech Connect

The U.S. Consumer Product Safety Commission is investigating chemical emissions from carpet systems in order to determine whether the emissions may be responsible for the numerous health complaints associated with carpet installation. As part of this effort, a study was conducted to identify and quantify volatile organic compounds (VOCs) released into the air by five major product types of new carpet cushions. Cushion samples were tested in small-volume dynamic chambers over a six-hour exposure period. Airborne VOCs collected on multisorbent samplers were identified using sensitive gas chromatography/mass spectrometry. A separate chamber method was developed to screen polyurethane cushions for emissions of toluene diisocyanates (TDI). Over 100 VOCs, spanning a broad range of chemical classes, were emitted from 17 carpet cushions. The pattern of emitted VOCs varied between and among product types, which reflects probable differences in manufacturing processes and ingredients. No significant quantities of TDI or formaldehyde were released by any cushions. Emission profiles were characterized for total VOCs and for the predominant individual VOCs. As a group, the synthetic fiber cushion samples emitted the lowest quantities of VOCs. Cushion samples purchased from carpet retailers released lesser amounts of VOCs than samples of the same cushion types obtained directly from the manufacturing mills. 11 refs., 2 figs., 3 tabs.

Schaeffer, V.H.; Bhooshan, B.; Chen, S.B.; Sonenthal, J.S. [Consumer Product Safety Commission, Washington, DC (United States); Hodgson, A.T. [Lawrence Berkeley National Lab., Berkeley, CA (United States)

1996-09-01

44

Motor Vehicles, Air Pollution, and Climate Change  

NASA Astrophysics Data System (ADS)

Despite years of technical progress, motor vehicles continue to be a leading cause of environmental damage in the United States. For example, today's cars and trucks are the largest source of air pollution in many urban areas. US motor vehicles also account for 25 percent of the nation's carbon emissions, more than most countries emit from all sources combined. Fortunately, a host of technical improvements are emerging that could go a long ways towards taking vehicles out of the pollution picture. In the near-term, improving on the century-old internal combustion engine can deliver much-needed incremental gains. But electric drive vehicles--whether powered by batteries, small engines in hybrid configuration, or fuel cells--ultimately offer the greatest promise. Such technologies could dramatically reduce energy use, greenhouse gas emissions, and key air pollutants. The bulk of technical attention in recent years has been focused on improving the passenger vehicle, which will be the dominant energy consumer in the transportation sector for years to come. But freight trucks are also of growing concern, both because their contribution to global warming is on the rise and because serious questions are being raised about the public health impact of diesel technology. As a result, heavy trucks are emerging as a priority issue. Capitalizing on the opportunity presented by new technologies will not only require continued technical innovation but also policy action. As research into improved engines, fuels, and drive systems bears fruit over the coming years, aggressive and prudent policies will ensure that these new options make it onto the road and deliver on their environmental promise.

Mark, Jason

2000-04-01

45

Towards the development of gyroscopically controlled micro air vehicles  

Microsoft Academic Search

Micro air vehicles have emerged as a popular option for diverse robotic and teleoperated applications because of their inherent stealth, portability, and disposability. In this work, we adopt a system-level perspective for the development of a rotary-wing micro air vehicle and propose a new design that utilizes gyroscopic dynamics for attitude control. Unlike tradi- tional vehicles where attitude control moments

Chris E. Thorne; Mark Yim

2011-01-01

46

Optimal air-breathing launch vehicle design  

NASA Technical Reports Server (NTRS)

A generalized two-point boundary problem methodology, similar to techniques used in deterministic optimal control studies, is applied to the design and flight analysis of a two-stage air-breathing launch vehicle. Simultaneous consideration is given to configuration and trajectory by treating geometry, dynamic discontinuities, and time-dependent flight variables all as controls to be optimized with respect to a single mathematical performance measure. While minimizing fuel consumption, inequality constraints are applied to dynamic pressure and specific force. The optimal system fuel consumption and staging Mach number are found to vary little with changes in the inequality constraints due to substantial geometry and trajectory adjustments. Staging, from an air-breathing first stage to a rocket-powered second stage, consistently occurs near Mach 3.5. The dynamic pressure bound has its most pronounced effects on vehicle geometry, particularly the air-breathing propulsion inlet area, and on the first-stage altitude profile. The specific force has its greatest influence on the second-stage thrust history.

Hattis, P. D.

1981-01-01

47

Analysis for SNF Multi Canister Overpack (MCO) Drop into the Cask from the MCO Handling Machine (MHM) with Air Cushion  

SciTech Connect

The purpose of this report is to investigate the potential for damage to the MCO during impact from an accidental drop from the MHM into the shipping cask. The MCO is dropped from a height of 8.2 feet above the cask enters the cask concentrically and falls the additional 12.83 feet to the cask bottom. Because of the interface fit between the MCO and the cask and the air entrapment the MCO fall velocity is slowed. The shipping cask is resting on an impact absorber at the time of impact. The energy absorbing properties of the impact absorber are included in this analysis.

RAINS, D.J.

2000-01-12

48

Avionics systems design for cooperative unmanned air and ground vehicles  

E-print Network

This thesis summarizes the results of the design of avionics systems intended for use onboard unmanned air and ground vehicles, that are parts of a multi-vehicle system whose primary mission objective is to provide up-close ...

Omelchenko, Alexander, 1968-

2004-01-01

49

Zinc air battery development for electric vehicles  

SciTech Connect

This report summarizes the results of research conducted during the sixteen month continuation of a program to develop rechargeable zinc-air batteries for electric vehicles. The zinc-air technology under development incorporates a metal foam substrate for the zinc electrode, with flow of electrolyte through the foam during battery operation. In this soluble'' zinc electrode the zincate discharge product dissolves completely in the electrolyte stream. Cycle testing at Lawrence Berkeley Laboratory, where the electrode was invented, and at MATSI showed that this approach avoids the zinc electrode shape change phenomenon. Further, electrolyte flow has been shown to be necessary to achieve significant cycle life (> 25 cycles) in this open system. Without it, water loss through the oxygen electrode results in high-resistance failure of the cell. The Phase I program, which focused entirely on the zinc electrode, elucidated the conditions necessary to increase electrode capacity from 75 to as much as 300 mAh/cm{sup 2}. By the end of the Phase I program over 500 cycles had accrued on one of the zinc-zinc half cells undergoing continuous cycle testing. The Phase II program continued the half cell cycle testing and separator development, further refined the foam preplate process, and launched into performance and cycle life testing of zinc-air cells.

Putt, R.A.; Merry, G.W. (MATSI, Inc., Atlanta, GA (United States))

1991-07-01

50

Viscoelastic cushion for patient support  

NASA Technical Reports Server (NTRS)

Flexible container, filled with liquid, provides supportive device which conforms to patient's anatomy. Uniform cushion pressure prevents formation of decubitus ulcers, while the porous sponge substructure damps fluid movement through cushion response so that patient is not dumped when his weight shifts.

Sauers, D. G.

1971-01-01

51

Nonlinear Trajectory Generation for Unmanned Air Vehicles with Multiple Radars  

E-print Network

Air Vehicles (UAVs) is radar detection systems. Designing optimal tra- jectories for UAV's which the probability of detection (to maxi- mize the probability of not­being­detected, pnd, function) of unmanned air vehicles by opponent radar detection systems is investigated. This paper extends our preliminary results

Murray, Richard M.

52

Air-Conditioning for Electric Vehicles  

NASA Technical Reports Server (NTRS)

Combination of ammonia-absorption refrigerator, roof-mounted solar collectors, and 200 degrees C service electric-vehicle motor provides evaporative space-heating/space cooling system for electric-powered and hybrid fuel/electric vehicles.

Popinski, Z.

1984-01-01

53

Seat cushion to provide realistic acceleration cues to aircraft simulator pilot  

NASA Technical Reports Server (NTRS)

Seat cushions, each including an air cell with a non-compressible surface, are disclosed. The apparatus are provided for initially controlling the air pressure in the air cells to allow the two main support areas of the simulator pilot to touch the non-compressible surface and thus begin to compress the flesh near these areas. During a simulated flight the apparatus control the air pressure in the cells to simulate the events that occur in a seat cushion during actual flight.

Ashworth, B. R. (inventor)

1979-01-01

54

Interior Beale Air Force Base, Perimeter Acquisition Vehicle Entry ...  

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

Interior - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Gate House, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

55

Looking north Beale Air Force Base, Perimeter Acquisition Vehicle ...  

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

Looking north - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Electric Substation, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

56

Interior view Beale Air Force Base, Perimeter Acquisition Vehicle ...  

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

Interior view - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Satellite Communications Terminal, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

57

Offutt Air Force Base, Looking Glass Airborne Command Post, Vehicle ...  

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

Offutt Air Force Base, Looking Glass Airborne Command Post, Vehicle Refueling Station, Northeast of AGE Storage Facility at far northwest end of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

58

MODELING AND SIMULATION OF FLAPPING WING MICRO AIR VEHICLES  

Microsoft Academic Search

This paper presents modeling and simulation of a flapping wing micro air vehicle. The overall geometry of this vehicle is based on hummingbirds and large insects. The purpose of this study is to understand the mechanics of flight and to achieve a preliminary design based on simulation results. A quasi- unsteady aerodynamic model is used based on in-house exper- imental

Sunil K. Agrawal

59

Robotic air vehicle. Blending artificial intelligence with conventional software  

NASA Technical Reports Server (NTRS)

The Robotic Air Vehicle (RAV) system is described. The program's objectives were to design, implement, and demonstrate cooperating expert systems for piloting robotic air vehicles. The development of this system merges conventional programming used in passive navigation with Artificial Intelligence techniques such as voice recognition, spatial reasoning, and expert systems. The individual components of the RAV system are discussed as well as their interactions with each other and how they operate as a system.

Mcnulty, Christa; Graham, Joyce; Roewer, Paul

1987-01-01

60

Gust Mitigation of Micro Air Vehicles Using Passive Articulated Wings  

PubMed Central

Birds and insects naturally use passive flexing of their wings to augment their stability in uncertain aerodynamic environments. In a similar manner, micro air vehicle designers have been investigating using wing articulation to take advantage of this phenomenon. The result is a class of articulated micro air vehicles where artificial passive joints are designed into the lifting surfaces. In order to analyze how passive articulation affects performance of micro air vehicles in gusty environments, an efficient 8 degree-of-freedom model is developed. Experimental validation of the proposed mathematical model was accomplished using flight test data of an articulated micro air vehicle obtained from a high resolution indoor tracking facility. Analytical investigation of the gust alleviation properties of the articulated micro air vehicle model was carried out using simulations with varying crosswind gust magnitudes. Simulations show that passive articulation in micro air vehicles can increase their robustness to gusts within a range of joint compliance. It is also shown that if articulation joints are made too compliant that gust mitigation performance is degraded when compared to a rigid system. PMID:24516368

Slegers, Nathan

2014-01-01

61

Innovative decision-making methods for the preliminary design and operations of air-cushion and other marine vehicles  

E-print Network

Ship design is a large-scale, multi-level, complex problem that requires decision-making at every stage of the design process. As such, it requires a great deal of time and resources. The evolution of the process of ship ...

Gougoulidis, Georgios

2011-01-01

62

280 Solutions Manual x Fluid Mechanics, Fifth Edition 3.160 The air-cushion vehicle in Fig.  

E-print Network

in a rectangular pattern (2592 holes total), the required jet speed from each hole is 50 ft/s. You must select required a jet lbf p p p V Ans. ft U ' 2 lbf 0.0204 in The total volume flow required is 2 1 3 1

Bahrami, Majid

63

Honeywell's organic air vehicle chemical-biological sensing platform  

NASA Astrophysics Data System (ADS)

Unmanned air vehicles (UAVs) today are mostly used for reconnaissance and sometimes weapons delivery. Remote sensing of chemical-biological (CB) agents is another beneficial use of UAVs. While remote sensing of CB agents can be done by LIDAR spectroscopy, this technology is less spatially precise and less sensitive than actual measurements on a collected sample. One family of UAVs of particularly unique benefit for CB sampling and in-flight analysis is the Honeywell family of Organic Air Vehicles (OAVs). This vehicle with its ability to hover and stare has the unique ability among UAVs to collect and analyze chem-bio samples from a specific location over extended periods of time. Such collections are not possible with other micro-air-vehicles (MAVs) that only operate in fly-by mode. This paper describes some of the Honeywell OAV features that are conducive to CB detection.

Cole, Barry E.; Krafthefer, Brian; Knee, Daniel; Fulton, Vaughn M.; Law, Kristen

2004-12-01

64

Missions and vehicle concepts for modern, propelled, lighter-than-air vehicles  

NASA Technical Reports Server (NTRS)

The results of studies conducted over the last 15 years to assess missions and vehicle concepts for modern, propelled, lighter-than-air vehicles (airships) were surveyed. Rigid and non-rigid airship concepts are considered. The use of airships for ocean patrol and surveillance is discussed along with vertical heavy lift airships. Military and civilian needs for high altitude platforms are addressed.

Ardema, M. D.

1984-01-01

65

Dioxin-receptor Ligands in Urban Air and Vehicle Exhaust  

Microsoft Academic Search

The ability of extracts of urban air and vehicle exhaust particulates to bind to the dioxin receptor has been determined. It was shown that such extracts do contain significant amounts of dioxin-receptor binding activity. The level of dioxin-receptor binding found in ambient air reflects its pollution level as determined by mutagenic activity. Furthermore, it was shown that the extracts of

Grant G. F. Mason

66

79 FR 23413 - Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards  

Federal Register 2010, 2011, 2012, 2013, 2014

...Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards; Final Rule Federal Register...Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards AGENCY: Environmental Protection...addressing the impacts of motor vehicles and fuels on air quality and public health....

2014-04-28

67

Flexible Wing Base Micro Aerial Vehicles: Assessment of Controllability of Micro Air Vehicles  

NASA Technical Reports Server (NTRS)

In the last several years, we have developed unique types of micro air vehicles that utilize flexible structures and extensible covering materials. These MAVs can be operated with maximum dimensions as small as 6 inches and carry reasonable payloads, such as video cameras and transmitters. We recently demonstrated the potential of these vehicles by winning the Fourth International Micro Air Vehicle Competition, held at Ft. Huachucha, Arizona in May 2000. The pilots report that these vehicles have unusually smooth flying characteristics and are relatively easy to fly, both in the standard RC mode and "through the camera" when at greater distances. In comparison, they find that similar sized vehicles with more conventional rigid construction require much more input from the pilot just to maintain control. To make these subjective observations more quantitative, we have devised a system that can conveniently record a complete history of all the RC transmitter stick movements during a flight. Post-flight processing of the stick movement data allows for direct comparisons between different types of MAVs when flown by the same pilot, and also comparisons between pilots. Eventually, practical micro air vehicles will be autonomously controlled, but we feel that the smoothest flying and easiest to fly embodiments will also be the most successful in the long run. Comparisons between several types of micro air vehicles will be presented, along with interpretations of the data.

Jenkins, David A.; Ifju, Peter G.; Abdulrahim, Mujahid; Olipra, Scott

2002-01-01

68

Effect of Intake Air Filter Condition on Vehicle Fuel Economy  

SciTech Connect

The U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy and the U.S. Environmental Protection Agency (EPA) jointly maintain a fuel economy website (www.fueleconomy.gov), which helps fulfill their responsibility under the Energy Policy Act of 1992 to provide accurate fuel economy information [in miles per gallon (mpg)] to consumers. The site provides information on EPA fuel economy ratings for passenger cars and light trucks from 1985 to the present and other relevant information related to energy use such as alternative fuels and driving and vehicle maintenance tips. In recent years, fluctuations in the price of crude oil and corresponding fluctuations in the price of gasoline and diesel fuels have renewed interest in vehicle fuel economy in the United States. (User sessions on the fuel economy website exceeded 20 million in 2008 compared to less than 5 million in 2004 and less than 1 million in 2001.) As a result of this renewed interest and the age of some of the references cited in the tips section of the website, DOE authorized the Oak Ridge National Laboratory (ORNL) Fuels, Engines, and Emissions Research Center (FEERC) to initiate studies to validate and improve these tips. This report documents a study aimed specifically at the effect of engine air filter condition on fuel economy. The goal of this study was to explore the effects of a clogged air filter on the fuel economy of vehicles operating over prescribed test cycles. Three newer vehicles (a 2007 Buick Lucerne, a 2006 Dodge Charger, and a 2003 Toyota Camry) and an older carbureted vehicle were tested. Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased. The carbureted engine did show a decrease in fuel economy with increasing restriction. However, the level of restriction required to cause a substantial (10-15%) decrease in fuel economy (such as that cited in the literature) was so severe that the vehicle was almost undrivable. Acceleration performance on all vehicles was improved with a clean air filter. Once it was determined how severe the restriction had to be to affect the carbureted vehicle fuel economy, the 2007 Buick Lucerne was retested in a similar manner. We were not able to achieve the level of restriction that was achieved with the 1972 Pontiac with the Lucerne. The Lucerne's air filter box would not hold the filter in place under such severe conditions. (It is believed that this testing exceeded the design limits of the air box.) Tests were conducted at a lower restriction level (although still considerably more severe than the initial clogged filter testing), allowing the air filter to stay seated in the air box, and no significant change was observed in the Lucerne's fuel economy or the AFR over the HFET cycle. Closed-loop control in modern fuel injected vehicle applications is sophisticated enough to keep a clogged air filter from affecting the vehicle fuel economy. However for older, open-loop, carbureted vehicles, a clogged air filter can affect the fuel economy. For the vehicle tested, the fuel economy with a new air filter improved as much as 14% over that with a severely clogged filter (in which the filter was so clogged that drivability was impacted). Under a more typical state of clog, the improvement with a new filter ranged from 2 to 6%.

Norman, Kevin M [ORNL; Huff, Shean P [ORNL; West, Brian H [ORNL

2009-02-01

69

Prototype air bag restraint for use in patrol vehicles  

SciTech Connect

An air bag has been designed and laboratory tested for use in existing police vehicles that will restrain a person if he or she becomes violent. The device will prevent self-injury and protect the vehicle and officer. The device does not pose a suffocation hazard and can be quickly and easily inflated or deflated by the officer from the front seat. The device is ready for field testing.

Marts, D.J.; Barker, S.G.

1995-03-01

70

Yaw rate control of an air bearing vehicle  

NASA Technical Reports Server (NTRS)

The results of a 6 week project which focused on the problem of controlling the yaw (rotational) rate the air bearing vehicle used on NASA's flat floor facility are summarized. Contained within is a listing of the equipment available for task completion and an evaluation of the suitability of this equipment. The identification (modeling) process of the air bearing vehicle is detailed as well as the subsequent closed-loop control strategy. The effectiveness of the solution is discussed and further recommendations are included.

Walcott, Bruce L.

1989-01-01

71

Department of Mechanical Engineering Spring 2011 General Motors 2 Variable Height Vehicle Air Dam  

E-print Network

Vehicle Air Dam Overview The fundamental issue with fixed air dams is the bottom edge of the dam needs to be high enough to meet defined vehicle ground clearance and front approach angle criteria. Air dams must a solution to this problem by designing an variable height vehicle air dam. Objectives Our mission

Demirel, Melik C.

72

Air inlet with variable intake section: Application to air breathing launch vehicles  

NASA Astrophysics Data System (ADS)

The feasibility of air breathing propulsion for future space launch vehicles largely depends on the possibility of designing air intakes that will give the best trade-off between internal performance and which will provide suitable air supply to the engine, weight reduction, and aerodynamic drag. The trade-off can be markedly improved by using air intake designs with variable absorption sections. The design concepts are defined and their application to space launch vehicles is analyzed with respect to internal performance, mass, and aerodynamic drag.

Falempin, F.; Duveau, Ph.

1992-09-01

73

Air-Breathing Launch Vehicle Technology Being Developed  

NASA Technical Reports Server (NTRS)

Of the technical factors that would contribute to lowering the cost of space access, reusability has high potential. The primary objective of the GTX program is to determine whether or not air-breathing propulsion can enable reusable single-stage-to-orbit (SSTO) operations. The approach is based on maturation of a reference vehicle design with focus on the integration and flight-weight construction of its air-breathing rocket-based combined-cycle (RBCC) propulsion system.

Trefny, Charles J.

2003-01-01

74

Study of long term options for electric vehicle air conditioning  

SciTech Connect

There are strong incentives in terms of national energy and environmental policy to encourage the commercialization of electrically powered vehicles in the U.S. Among these incentives are reduced petroleum consumption, improved electric generation capacity utilization, reduced IC engine emissions, and, depending on the primary fuel used for electric power generation, reduced emissions of carbon dioxide. A basic requirement for successfully commercializing any motor vehicle in the US is provision of adequate passenger comfort heating and air conditioning (cooling). Although air conditioning is generally sold as optional equipment, in excess of 80% of the automobiles and small trucks sold in the US have air conditioning systems. In current, pre-commercial electric vehicles, comfort heating is provided by a liquid fuel fired heater that heats water which is circulated through the standard heater core in the conventional interior air handling unit. Air conditioning is provided by electric motor driven compressors, installed in a system having, perhaps, an [open quotes]upsized[close quotes] condenser and a standard evaporator (front and rear evaporators in some instances) installed in the conventional interior air handler. Although this approach is adequate in the near term for initial commercialization efforts, a number of shortcomings of this arrangement, as well as longer range concerns need to be addressed. In this project, the long term alternatives for cooling and heating electric vehicles effectively, efficiently (with minimum range penalties), and without adverse environmental impacts have been examined. Identification of options that can provide both heating and cooling is important, in view of the disadvantages of carrying separate heating and cooling systems in the vehicle.

Dieckmann, J.; Mallory, D. (Little (Arthur D.), Inc., Cambridge, MA (United States))

1991-07-01

75

Study of long term options for electric vehicle air conditioning  

SciTech Connect

There are strong incentives in terms of national energy and environmental policy to encourage the commercialization of electrically powered vehicles in the U.S. Among these incentives are reduced petroleum consumption, improved electric generation capacity utilization, reduced IC engine emissions, and, depending on the primary fuel used for electric power generation, reduced emissions of carbon dioxide. A basic requirement for successfully commercializing any motor vehicle in the US is provision of adequate passenger comfort heating and air conditioning (cooling). Although air conditioning is generally sold as optional equipment, in excess of 80% of the automobiles and small trucks sold in the US have air conditioning systems. In current, pre-commercial electric vehicles, comfort heating is provided by a liquid fuel fired heater that heats water which is circulated through the standard heater core in the conventional interior air handling unit. Air conditioning is provided by electric motor driven compressors, installed in a system having, perhaps, an {open_quotes}upsized{close_quotes} condenser and a standard evaporator (front and rear evaporators in some instances) installed in the conventional interior air handler. Although this approach is adequate in the near term for initial commercialization efforts, a number of shortcomings of this arrangement, as well as longer range concerns need to be addressed. In this project, the long term alternatives for cooling and heating electric vehicles effectively, efficiently (with minimum range penalties), and without adverse environmental impacts have been examined. Identification of options that can provide both heating and cooling is important, in view of the disadvantages of carrying separate heating and cooling systems in the vehicle.

Dieckmann, J.; Mallory, D. [Little (Arthur D.), Inc., Cambridge, MA (United States)

1991-07-01

76

Obstacle Avoidance For Unmanned Air Vehicles Using Image Feature Tracking  

Microsoft Academic Search

This paper discusses a computer vision algorithm and a control law for obstacle avoid- ance for small unmanned air vehicles using a video camera as the primary sensor. Small UAVs are used for low altitude surveillance ?ights where unknown obstacles can be en- countered. Small UAVs can be given the capability to navigate in uncertain environments if obstacles are identifled.

Brandon Call; Randy Beard; Clark Taylor

77

Low-observable nonlinear trajectory generation for unmanned air vehicles  

Microsoft Academic Search

This paper explores low observability flight path planning of unmanned air vehicles (UAVs) in the presence of radar detection systems. The probability of detection model of an aircraft near an opponent radar depends on aircraft attitude, range, and configuration. A detection model is coupled with a simplified aircraft dynamics model. The nonlinear trajectory generation (NTG) software package developed at Caltech

K. Misovec; T. Inanc; J. Wohletz; R. M. Murray

2003-01-01

78

Nonlinear trajectory generation for unmanned air vehicles with multiple radars  

Microsoft Academic Search

The problem of finding a real time optimal trajectory to minimize the probability of detection of unmanned air vehicles by opponent radar detection systems is investigated. This paper extends our preliminary results on low observable trajectory generation in three ways. First, trajectory planning in the presence of detection by multiple radar systems, rather than a single radar system, is considered.

Tamer Inanc; Kathy Misovec; Richard M. Murray

2004-01-01

79

The real air quality benefits of gaseous-fueled vehicles.  

SciTech Connect

This paper provides a justification for prominent inclusion of currently available gaseous-fueled vehicles (i.e., vehicles powered by propane, sometimes called liquefied petroleum gas [LPG], or natural gas--chiefly, methane--stored onboard the vehicle in gaseous or liquid state but combusted as a gas) in the mix of strategies to (a) reduce public exposure to toxic and fine particulate emissions in the urbanized areas of the developing world and (b) achieve local and regional improvements in ozone air quality. It also presents estimates of associated emission reduction credits into the future. Important considerations discussed are the location of fine particle and toxic emissions in congested urban areas, and the location and timing of ozone precursor emissions, with emphasis on how gaseous-fueled vehicles' role in the relationship among and magnitude of these variables differs from that of their conventionally-fueled counterparts. Efforts to enhance the measurement and quantification of gaseous-fuel benefits are also described.

Saricks, C. L.

2002-03-28

80

Abstract--Unmanned Air Vehicles (UAVs) have several advantages and disadvantages compared with Unmanned  

E-print Network

, Florida. Recently, unmanned aerial vehicles (UAVs) have been used more extensively for militaryAbstract--Unmanned Air Vehicles (UAVs) have several advantages and disadvantages compared with Unmanned Ground Vehicles (UGVs). Both systems have different mobility and perception abilities. UAV systems

Florida, University of

81

TAITKLMLENDRMESNDE ALTERNATF KLMA SSTEMLERNN KULLANIMININ ARATIRILMASI INVESTIGATION OF USING ALTERNATIVE AIR CONDITIONING SYSTEMS IN VEHICLE AIR CONDITIONING  

Microsoft Academic Search

In this study, It has been researched and compared to employability of alternative air containing to classical vapor compressed vehicle air containing, environmental effects, principles of work of systems and performances of cooling. For environmental effects in automobiles; workings in subject of usages of various air containing systems instead of vapor compressed vehicle air containing is to attend more and

Muhammet KAYFEC; Selami SAIROLU

82

Development of a low-cost crash cushion using recycled automobile tires. Final report  

Microsoft Academic Search

Approximately thirty percent of all vehicle related fatalities that occur each year caused by a single vehicle leaving the road and striking a fixed object; the most common objects struck being trees, guardrails, and utility poles. In many cases current crash cushion systems are not cost effective to be installed on such obstacles. In addition to high initial costs many

D. T. Habors; M. Hossain

1998-01-01

83

AUTOMOBILE HVAC SYSTEMS: AIR FLOW, LEAKAGE AND THEIR EFFECTS ON IN-VEHICLE AIR QUALITY  

Microsoft Academic Search

We have sought to accurately quantify automobile HVAC air flow rates in four passenger vehicles, under a range of different ventilation settings and speeds. We used Sulphur Hexafluoride (SF6) as a tracer gas, coupled with a portable doser\\/sampler system to quantify flow rates and leakage. Results of this work indicate a linear increase in HVAC air flow rate with increasing

Luke D. Knibbs; Richard J. de Dear; Steven E. Atkinson

84

Prospects for future hypersonic air-breathing vehicles  

NASA Technical Reports Server (NTRS)

The age of hypersonics is (almost) here. This is evident from the amount of activity in the United States, Europe, the USSR and Japan; this activity is a reflection of technical progress in key areas which will enable new vehicle systems, as well as renewed interest in the utilization of these systems. The current situation, at least in the United States, is the product of an interesting history which is briefly reviewed here. The context for hypersonic applications is discussed, but the emphasis is on hypersonic technology issues and needs, particularly for propulsion and technology integration. The paper concludes with prospects for accomplishing the objective of air-breathing hypersonic vehicle systems.

Beach, H. L., Jr.; Blankson, Isaiah M.

1991-01-01

85

75 FR 6338 - Protection of Stratospheric Ozone: New Substitute in the Motor Vehicle Air Conditioning Sector...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Substitute in the Motor Vehicle Air Conditioning Sector Under the Significant New Alternatives...substitute for CFC-12 in motor vehicle air conditioning. The proposed substitute is a non-ozone-depleting...alternative refrigerant for motor vehicle air conditioning, subject to use conditions. The...

2010-02-09

86

77 FR 33315 - Protection of Stratospheric Ozone: Alternative for the Motor Vehicle Air Conditioning Sector...  

Federal Register 2010, 2011, 2012, 2013, 2014

...impair the driver's response...light-duty vehicles (76 FR 17488...in Motor Vehicle Air Conditioning...Vehicle Driver and Passenger...light duty vehicles (EPA-HQ-OAR-2008-0644...area in the vehicle being regulated...focus on the driver...

2012-06-06

87

Attachment device for an inflatable protective cushion  

DOEpatents

An inflatable cushion assembly for use with an inflator comprises an inflatable cushion having an inner surface, outer surface, and at least one protrusion extending from one of the inner or outer surfaces. The inflatable cushion defines an opening between the inner surface and the outer surface for receiving the inflator. An attachment member contacts the one of the inner or outer surfaces adjacent the opening and includes a groove for receiving the protrusion, the attachment member securing the inflator within the opening.

Nelsen, James M. (Albuquerque, NM); Luna, Daniel A. (Los Lunas, NM); Gwinn, Kenneth W. (Cedar Crest, NM)

1998-01-01

88

Attachment device for an inflatable protective cushion  

DOEpatents

An inflatable cushion assembly for use with an inflator comprises an inflatable cushion having an inner surface, outer surface, and at least one protrusion extending from one of the inner or outer surfaces. The inflatable cushion defines an opening between the inner surface and the outer surface for receiving the inflator. An attachment member contacts the one of the inner or outer surfaces adjacent the opening and includes a groove for receiving the protrusion, the attachment member securing the inflator within the opening.

Nelsen, James M. (Albuquerque, NM); Luna, Daniel A. (Los Lunas, NM); Gwinn, Kenneth W. (Cedar Crest, NM)

1997-01-01

89

21 CFR 890.3175 - Flotation cushion.  

Code of Federal Regulations, 2014 CFR

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion. (a) Identification. A flotation...

2014-04-01

90

21 CFR 890.3175 - Flotation cushion.  

Code of Federal Regulations, 2010 CFR

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion. (a) Identification. A flotation...

2010-04-01

91

21 CFR 890.3175 - Flotation cushion.  

Code of Federal Regulations, 2013 CFR

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion. (a) Identification. A flotation...

2013-04-01

92

21 CFR 890.3175 - Flotation cushion.  

Code of Federal Regulations, 2011 CFR

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion. (a) Identification. A flotation...

2011-04-01

93

A Compact Millimeter Wave Radar Sensor for Unmanned Air Vehicles  

Microsoft Academic Search

This paper presents a compact Millimeter Wave (MMW) radar unit that has been developed to be used as a Range, Bearing and\\u000a Elevation (RBE) sensor on the Brumby Mk III Unmanned Air Vehicles (UAV). The Brumby MkIII is the flight platform used in the\\u000a Autonomous Navigation and Sensing Experimental Research (ANSER) project which is focused on the development and demonstration

Ali Göktogan; Graham Brooker; Salah Sukkarieh

2003-01-01

94

In-vehicle particle air pollution and its mitigation  

NASA Astrophysics Data System (ADS)

This work presents results of particle mass, number and size measurements inside passenger cars (PCs), vans and urban buses. Effects of the in-cabin air purifier on particle concentrations and average size inside a vehicle are studied. Use of the air purifier leads to a dramatic reduction, by 95-99%, in the measured ultrafine particles number concentration inside a vehicle compared with outside readings. Extremely low particle concentrations may be reached without a danger of vehicle occupants' exposure to elevated CO2 levels. The lowest values of particle concentrations inside a PC without air purifier are registered under the recirculation ventilation mode, but the issue of CO2 accumulation limits the use of this mode to very short driving events. Lower PM concentrations are found inside newer cars, if this ventilation mode is used. Great differences by a factor of 2.5-3 in PM10 concentrations are found between the PCs and the buses. Smoking inside a car leads to a dramatic increase, by approximately 90 times, in PM2.5 concentrations.

Tartakovsky, L.; Baibikov, V.; Czerwinski, J.; Gutman, M.; Kasper, M.; Popescu, D.; Veinblat, M.; Zvirin, Y.

2013-01-01

95

40 CFR 86.1832-01 - Optional equipment and air conditioning for test vehicles.  

Code of Federal Regulations, 2012 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL...Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty...1832-01 Optional equipment and air conditioning for test vehicles....

2012-07-01

96

40 CFR 86.1832-01 - Optional equipment and air conditioning for test vehicles.  

Code of Federal Regulations, 2014 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL...Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty...1832-01 Optional equipment and air conditioning for test vehicles....

2014-07-01

97

40 CFR 86.1832-01 - Optional equipment and air conditioning for test vehicles.  

Code of Federal Regulations, 2011 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL...Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty...1832-01 Optional equipment and air conditioning for test vehicles....

2011-07-01

98

40 CFR 86.1832-01 - Optional equipment and air conditioning for test vehicles.  

Code of Federal Regulations, 2013 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL...Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty...1832-01 Optional equipment and air conditioning for test vehicles....

2013-07-01

99

40 CFR 86.1832-01 - Optional equipment and air conditioning for test vehicles.  

Code of Federal Regulations, 2010 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL...Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty...1832-01 Optional equipment and air conditioning for test vehicles....

2010-07-01

100

High specific energy and specific power aluminum/air battery for micro air vehicles  

NASA Astrophysics Data System (ADS)

Micro air vehicles developed under the Army's Micro Autonomous Systems and Technology program generally need a specific energy of 300 - 550 watt-hrs/kg and 300 -550 watts/kg to operate for about 1 hour. At present, no commercial cell can fulfill this need. The best available commercial technology is the Lithium-ion battery or its derivative, the Li- Polymer cell. This chemistry generally provides around 15 minutes flying time. One alternative to the State-of-the Art is the Al/air cell, a primary battery that is actually half fuel cell. It has a high energy battery like aluminum anode, and fuel cell like air electrode that can extract oxygen out of the ambient air rather than carrying it. Both of these features tend to contribute to a high specific energy (watt-hrs/kg). High specific power (watts/kg) is supported by high concentration KOH electrolyte, a high quality commercial air electrode, and forced air convection from the vehicles rotors. The performance of this cell with these attributes is projected to be 500 watt-hrs/kg and 500 watts/kg based on simple model. It is expected to support a flying time of approximately 1 hour in any vehicle in which the usual limit is 15 minutes.

Kindler, A.; Matthies, L.

2014-06-01

101

77 FR 17344 - Protection of Stratospheric Ozone: Amendment to HFO-1234yf SNAP Rule for Motor Vehicle Air...  

Federal Register 2010, 2011, 2012, 2013, 2014

...equipment, and on all [motor vehicle] air conditioning system...refrigerant could leak without detection. Therefore, we are revising...Manufacturers must Additional training Vehicle Air Conditioning (New substitute...Safety Standards for Motor Vehicle Refrigerant Vapor...

2012-03-26

102

Conceptual design of flapping-wing micro air vehicles.  

PubMed

Traditional micro air vehicles (MAVs) are miniature versions of full-scale aircraft from which their design principles closely follow. The first step in aircraft design is the development of a conceptual design, where basic specifications and vehicle size are established. Conceptual design methods do not rely on specific knowledge of the propulsion system, vehicle layout and subsystems; these details are addressed later in the design process. Non-traditional MAV designs based on birds or insects are less common and without well-established conceptual design methods. This paper presents a conceptual design process for hovering flapping-wing vehicles. An energy-based accounting of propulsion and aerodynamics is combined with a one degree-of-freedom dynamic flapping model. Important results include simple analytical expressions for flight endurance and range, predictions for maximum feasible wing size and body mass, and critical design space restrictions resulting from finite wing inertia. A new figure-of-merit for wing structural-inertial efficiency is proposed and used to quantify the performance of real and artificial insect wings. The impact of these results on future flapping-wing MAV designs is discussed in detail. PMID:22498507

Whitney, J P; Wood, R J

2012-09-01

103

Projection Moire Interferometry Measurements of Micro Air Vehicle Wings  

NASA Technical Reports Server (NTRS)

Projection Moire Interferometry (PMI) has been used to measure the structural deformation of micro air vehicle (MAV) wings during a series of wind tunnel tests. The MAV wings had a highly flexible wing structure, generically reminiscent of a bat s wing, which resulted in significant changes in wing shape as a function of MAV angle-of-attack and simulated flight speed. This flow-adaptable wing deformation is thought to provide enhanced vehicle stability and wind gust alleviation compared to rigid wing designs. Investigation of the potential aerodynamic benefits of a flexible MAV wing required measurement of the wing shape under aerodynamic loads. PMI was used to quantify the aerodynamically induced changes in wing shape for three MAV wings having different structural designs and stiffness characteristics. This paper describes the PMI technique, its application to MAV testing, and presents a portion of the PMI data acquired for the three different MAV wings tested.

Fleming, Gary A.; Bartram, Scott M.; Waszak, Martin R.; Jenkins, Luther N.

2001-01-01

104

Effect of Intake Air Filter Condition on Light-Duty Gasoline Vehicles  

SciTech Connect

Proper maintenance can help vehicles perform as designed, positively affecting fuel economy, emissions, and the overall drivability. This effort investigates the effect of one maintenance factor, intake air filter replacement, with primary focus on vehicle fuel economy, but also examining emissions and performance. Older studies, dealing with carbureted gasoline vehicles, have indicated that replacing a clogged or dirty air filter can improve vehicle fuel economy and conversely that a dirty air filter can be significantly detrimental to fuel economy. The effect of clogged air filters on the fuel economy, acceleration and emissions of five gasoline fueled vehicles is examined. Four of these were modern vehicles, featuring closed-loop control and ranging in model year from 2003 to 2007. Three vehicles were powered by naturally aspirated, port fuel injection (PFI) engines of differing size and cylinder configuration: an inline 4, a V6 and a V8. A turbocharged inline 4-cylinder gasoline direct injection (GDI) engine powered vehicle was the fourth modern gasoline vehicle tested. A vintage 1972 vehicle equipped with a carburetor (open-loop control) was also examined. Results reveal insignificant fuel economy and emissions sensitivity of modern vehicles to air filter condition, but measureable effects on the 1972 vehicle. All vehicles experienced a measured acceleration performance penalty with clogged intake air filters.

Thomas, John F [ORNL] [ORNL; Huff, Shean P [ORNL] [ORNL; West, Brian H [ORNL] [ORNL; Norman, Kevin M [ORNL] [ORNL

2012-01-01

105

Avionics and control system development for mid-air rendezvous of two unmanned aerial vehicles  

E-print Network

A flight control system was developed to achieve mid-air rendezvous of two unmanned aerial vehicles (UAVs) as a part of the Parent Child Unmanned Aerial Vehicle (PCUAV) project at MIT and the Draper Laboratory. A lateral ...

Park, Sanghyuk, 1973-

2004-01-01

106

77 FR 3386 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Clean Vehicles Program  

Federal Register 2010, 2011, 2012, 2013, 2014

...Promulgation of Air Quality Implementation Plans; Pennsylvania; Clean Vehicles Program AGENCY: Environmental...revision submitted by the Commonwealth of Pennsylvania. This SIP revision contains Pennsylvania's Clean Vehicle Program, which...

2012-01-24

107

Electrospinning of a Micro-air Vehicle Wing Skin  

NASA Technical Reports Server (NTRS)

Electrospinning was utilized to create lightweight, electrically responsive wing skins for micro-air vehicle (MAV) wing frame designs. Various compositions of an electroactive polymer were investigated to determine the appropriate electrospinning conditions for these materials. Electrospun mats of these materials were characterized via optical microscopy and scanning electron microscopy. Tensile properties of the electrospun fibers were also measured. An optimal polymer composition was electrospun onto MAV wing frames to create a bird wing-like texture. Preliminary testing of electroactivity of these prototype MAV wings is reported here.

Pawlowski, K. J.; Belvin, H. L.; Raney, D. L.; Su, J.; Harrison, J. S.; Siochi, E. J.

2003-01-01

108

Factors that influence changes in wheelchair cushion performance over time.  

PubMed

Wheelchair cushions can be used for many hours every day. Like all devices, cushions degrade over time, losing the ability to provide adequate support. Little is known about the changes that cushions undergo after typical everyday use. This project was designed to monitor cushion performance over time with the objective to identify the most important factors that predict cushion degradation. Wheelchair users and their cushions were evaluated multiple times. Information was collected about participants' posture and activities, their cushions, and use of their cushions. Cushion performance was determined by measuring interface pressure using a buttock model. Data analysis proceeded in two steps. First, principal component analysis was run to reduce the number of variables. Second, multiple regression determined which variables influenced the interface pressure performance variables. Results indicated that user characteristics and the manner in which the cushion is used have a greater influence on cushion performance than the chronological age of the cushion. This result can be useful to clinicians who should query users about cushion use when investigating the need to replace a cushion. Finally, this information is applicable to policies that govern cushion replacement and indicted that wear on a cushion is not equivocal across users. PMID:25112050

Sprigle, Stephen; Delaune, William

2014-01-01

109

Modular disposable can (MODCAN) crash cushion: A concept investigation  

NASA Technical Reports Server (NTRS)

A conceptual design investigation of an improved highway crash cushion system is presented. The system is referred to as a modular disposable can (MODCAN) crash system. It is composed of a modular arrangement of disposable metal beverage cans configured to serve as an effective highway impact attenuation system. Experimental data, design considerations, and engineering calculations supporting the design development are presented. Design performance is compared to that of a conventional steel drum system. It is shown that the MODCAN concepts offers the potential for smoother and safer occupant deceleration for a larger class of vehicle impact weights than the steel drum device.

Knoell, A.; Wilson, A.

1976-01-01

110

CARS Temperature and Species Measurements For Air Vehicle Propulsion Systems  

NASA Technical Reports Server (NTRS)

The coherent anti-Stokes Raman spectroscopy (CARS) method has recently been used in the United States and Europe to probe several different types of propulsion systems for air vehicles. At NASA Langley Research Center in the United States, CARS has been used to simultaneously measure temperature and the mole fractions of N2, O2 and H2 in a supersonic combustor, representative of a scramjet engine. At Wright- Patterson Air Force Base in the United States, CARS has been used to simultaneously measure temperature and mole fractions of N2, O2 and CO2, in the exhaust stream of a liquid-fueled, gas-turbine combustor. At ONERA in France and the DLR in Germany researchers have used CARS to measure temperature and species concentrations in cryogenic LOX-H2 rocket combustion chambers. The primary aim of these measurements has been to provide detailed flowfield information for computational fluid dynamics (CFD) code validation.

Danehy, Paul M.; Gord, James R.; Grisch, Frederic; Klimenko, Dmitry; Clauss, Walter

2005-01-01

111

77 FR 16988 - Protection of Stratospheric Ozone: Amendment to HFO-1234yf SNAP Rule for Motor Vehicle Air...  

Federal Register 2010, 2011, 2012, 2013, 2014

...HFO-1234yf SNAP Rule for Motor Vehicle Air Conditioning Sector AGENCY: Environmental Protection...substances (ODSs) in the motor vehicle air conditioning end- use within the refrigeration and air conditioning sector, as acceptable subject to...

2012-03-23

112

Attachment device for an inflatable protective cushion  

DOEpatents

An inflatable cushion assembly for use with an inflator comprises an inflatable cushion having an inner surface, outer surface, and at least one protrusion extending from one of the inner or outer surfaces. The inflatable cushion defines an opening between the inner surface and the outer surface for receiving the inflator. An attachment member contacts the one of the inner or outer surfaces adjacent the opening and includes a groove for receiving the protrusion, the attachment member securing the inflator within the opening. 22 figs.

Nelsen, J.M.; Luna, D.A.; Gwinn, K.W.

1998-12-08

113

Attachment device for an inflatable protective cushion  

DOEpatents

An inflatable cushion assembly for use with an inflator comprises an inflatable cushion having an inner surface, outer surface, and at least one protrusion extending from one of the inner or outer surfaces. The inflatable cushion defines an opening between the inner surface and the outer surface for receiving the inflator. An attachment member contacts the one of the inner or outer surfaces adjacent the opening and includes a groove for receiving the protrusion, the attachment member securing the inflator within the opening. 22 figs.

Nelsen, J.M.; Luna, D.A.; Gwinn, K.W.

1997-11-18

114

GPS Auto-Navigation Design for Unmanned Air Vehicles  

NASA Technical Reports Server (NTRS)

A GPS auto-navigation system is designed for Unmanned Air Vehicles. The objective is to enable the air vehicle to be used as a test-bed for novel flow control concepts. The navigation system uses pre-programmed GPS waypoints. The actual GPS position, heading, and velocity are collected by the flight computer, a PC104 system running in Real-Time Linux, and compared with the desired waypoint. The navigator then determines the necessity of a heading correction and outputs the correction in the form of a commanded bank angle, for a level coordinated turn, to the controller system. This controller system consists of 5 controller! (pitch rate PID, yaw damper, bank angle PID, velocity hold, and altitude hold) designed for a closed loop non-linear aircraft model with linear aerodynamic coefficients. The ability and accuracy of using GPS data, is validated by a GPS flight. The autopilots are also validated in flight. The autopilot unit flight validations show that the designed autopilots function as designed. The aircraft model, generated on Matlab SIMULINK is also enhanced by the flight data to accurately represent the actual aircraft.

Nilsson, Caroline C. A.; Heinzen, Stearns N.; Hall, Charles E., Jr.; Chokani, Ndaona

2003-01-01

115

Updraft Model for Development of Autonomous Soaring Uninhabited Air Vehicles  

NASA Technical Reports Server (NTRS)

Large birds and glider pilots commonly use updrafts caused by convection in the lower atmosphere to extend flight duration, increase cross-country speed, improve range, or simply to conserve energy. Uninhabited air vehicles may also have the ability to exploit updrafts to improve performance. An updraft model was developed at NASA Dryden Flight Research Center (Edwards, California) to investigate the use of convective lift for uninhabited air vehicles in desert regions. Balloon and surface measurements obtained at the National Oceanic and Atmospheric Administration Surface Radiation station (Desert Rock, Nevada) enabled the model development. The data were used to create a statistical representation of the convective velocity scale, w*, and the convective mixing-layer thickness, zi. These parameters were then used to determine updraft size, vertical velocity profile, spacing, and maximum height. This paper gives a complete description of the updraft model and its derivation. Computer code for running the model is also given in conjunction with a check case for model verification.

Allen, Michael J.

2006-01-01

116

78 FR 19991 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Motor Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Air Quality Implementation Plans; Pennsylvania; Motor Vehicle Emissions Budgets for the Pennsylvania Counties in the Philadelphia-Wilmington...revision submitted by the Commonwealth of Pennsylvania (Pennsylvania). The revision...

2013-04-03

117

78 FR 11122 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Motor Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Air Quality Implementation Plans; Pennsylvania; Motor Vehicle Emissions Budgets for the Pennsylvania Counties in the Philadelphia-Wilmington...revision submitted by the Commonwealth of Pennsylvania (Pennsylvania). This proposed...

2013-02-15

118

Feasibility study of applying laminar flow control to an lta vehicle. Final report. [Lighter than air vehicles  

SciTech Connect

The feasibility of applying laminar boundary-layer control with body shaping to a high altitude, Lighter-Than-Air vehicle was investigated. Solar-radiation-induced surface heating was shown to have a destablizing effect on laminar flow and caused the laminar flow to break down on regions of the vehicle surface exposed to high levels of solar radiation. Aerodynamic drag estimates were made for the vehicle. Surface waviness and roughness criteria for achieving laminar flow were determined.

Warner, D.J.; Ozgur, S.A.; Haigh, W.W.

1980-04-01

119

Flexible Wing Base Micro Aerial Vehicles: Micro Air Vehicles (MAVs) for Surveillance and Remote Sensor Delivery  

NASA Technical Reports Server (NTRS)

Micro Air Vehicles (MAVs) will be developed for tracking individuals, locating terrorist threats, and delivering remote sensors, for surveillance and chemical/biological agent detection. The tasks are: (1) Develop robust MAV platform capable of carrying sensor payload. (2) Develop fully autonomous capabilities for delivery of sensors to remote and distant locations. The current capabilities and accomplishments are: (1) Operational electric (inaudible) 6-inch MAVs with novel flexible wing, providing superior aerodynamic efficiency and control. (2) Vision-based flight stability and control (from on-board cameras).

Ifju, Peter

2002-01-01

120

Optimal Trajectory Determination for Increased Relative Navigation Observability of Air Vehicles  

E-print Network

they Aerospace Engineer. Email: afrl.rvsv@kirtland.af.mil. Member AIAA. Professor, Department of Mechanical Adam M. Fosbury Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, NM

Crassidis, John L.

121

Vehicle expectations in air transportation for the year 2000  

NASA Technical Reports Server (NTRS)

This paper is intended to provide an overview of the air transportation system for the year 2000 in terms of vehicle expectations. Emphasis is placed on civil air transportation with the time period approached from the standpoint of evolutionary changes for the near term and also with the assumption of more revolutionary changes for the far term. The view along the evolutionary path begins with a historical review of airline market growth and the impact that technologies have had on airplane designs. Projections of the life expectancy of existing, derivative, and new airplanes are examined in terms of their productivity and fuel efficiency in view of the present and projected fuel usage and availability. The factors influencing airline growth are outlined and some views on whether another new generation of subsonic airplanes are in the offing are given along with an assessment of the economic viability of an advanced commercial supersonic transport in terms of its higher speed, higher productivity, and higher fuel usage. With regard to revolutionary changes, major technology breakthroughs are assumed to occur at a specified date. As an example, the impact of a dramatic reduction in skin friction drag is examined in terms of its effect on the airplane configuration, its propulsion systems, it projected fuel usage, and the air transportation system in which it must operate.

Hearth, D. P.

1980-01-01

122

Zinc air battery development for electric vehicles. Final report  

SciTech Connect

This report summarizes the results of research conducted during the sixteen month continuation of a program to develop rechargeable zinc-air batteries for electric vehicles. The zinc-air technology under development incorporates a metal foam substrate for the zinc electrode, with flow of electrolyte through the foam during battery operation. In this ``soluble`` zinc electrode the zincate discharge product dissolves completely in the electrolyte stream. Cycle testing at Lawrence Berkeley Laboratory, where the electrode was invented, and at MATSI showed that this approach avoids the zinc electrode shape change phenomenon. Further, electrolyte flow has been shown to be necessary to achieve significant cycle life (> 25 cycles) in this open system. Without it, water loss through the oxygen electrode results in high-resistance failure of the cell. The Phase I program, which focused entirely on the zinc electrode, elucidated the conditions necessary to increase electrode capacity from 75 to as much as 300 mAh/cm{sup 2}. By the end of the Phase I program over 500 cycles had accrued on one of the zinc-zinc half cells undergoing continuous cycle testing. The Phase II program continued the half cell cycle testing and separator development, further refined the foam preplate process, and launched into performance and cycle life testing of zinc-air cells.

Putt, R.A.; Merry, G.W. [MATSI, Inc., Atlanta, GA (United States)

1991-07-01

123

Flexible Wing Base Micro Aerial Vehicles: Composite Materials for Micro Air Vehicles  

NASA Technical Reports Server (NTRS)

This paper will discuss the development of the University of Florida's Micro Air Vehicle concept. A series of flexible wing based aircraft that possess highly desirable flight characteristics were developed. Since computational methods to accurately model flight at the low Reynolds numbers associated with this scale are still under development, our effort has relied heavily on trial and error. Hence a time efficient method was developed to rapidly produce prototype designs. The airframe and wings are fabricated using a unique process that incorporates carbon fiber composite construction. Prototypes can be fabricated in around five man-hours, allowing many design revisions to be tested in a short period of time. The resulting aircraft are far more durable, yet lighter, than their conventional counterparts. This process allows for thorough testing of each design in order to determine what changes were required on the next prototype. The use of carbon fiber allows for wing flexibility without sacrificing durability. The construction methods developed for this project were the enabling technology that allowed us to implement our designs. The resulting aircraft were the winning entries in the International Micro Air Vehicle Competition for the past two years. Details of the construction method are provided in this paper along with a background on our flexible wing concept.

Ifju, Peter G.; Ettinger, Scott; Jenkins, David; Martinez, Luis

2002-01-01

124

Cleaning the air and improving health with hydrogen fuel-cell vehicles  

Microsoft Academic Search

Converting all U.S. onroad vehicles to hydrogen fuel-cell vehicles (HFCVs) may improve air quality, health, and climate significantly, whether the hydrogen is produced by steam reforming of natural gas, wind electrolysis, or coal gasification. Most benefits would result from eliminating current vehicle exhaust. Wind and natural gas HFCVs offer the greatest potential health benefits and could save 3700 to 6400

M. Z. Jacobson; W. G. Colella; D. M. Golden

2005-01-01

125

Valuation of plug-in vehicle life-cycle air emissions and oil displacement benefits  

E-print Network

fewer greenhouse gas (GHG) emissions when powered by electricity instead of gasoline, de- pendingValuation of plug-in vehicle life-cycle air emissions and oil displacement benefits Jeremy J emissions and oil consumption from conventional vehicles, hybrid-electric vehicles (HEVs), plug-in hybrid

Michalek, Jeremy J.

126

Hazardous Air Pollution from Mobile Sources: A Comparison of Alternative Fuel and Reformulated Gasoline Vehicles  

Microsoft Academic Search

Although there have been several studies examining emissions of criteria pollutants from in-use alternative fuel vehicles (AFVs), little is known about emissions of hazardous air pollutants (HAPs) from these vehicles. This paper explores HAP tailpipe emissions from a variety of AFVs operating in the federal government fleet and compares these emissions to emissions from identical vehicles operating on reformulated gasoline.

James J. Winebrake; Michael L. Deaton

1999-01-01

127

Integration of an Autopilot for a Micro Air Vehicle  

NASA Technical Reports Server (NTRS)

Two autopilots providing autonomous flight capabilities are presented herein. The first is the Pico-Pilot, demonstrated for the 12-inch size class of micro air vehicles. The second is the MicroPilot MP2028(sup g), where its integration into a 36-inch Zagi airframe (tailless, elevons only configuration) is investigated and is the main focus of the report. Analytical methods, which include the use of the Advanced Aircraft Analysis software from DARCorp, were used to determine the stability and control derivatives, which were then validated through wind tunnel experiments. From the aerodynamic data, the linear, perturbed equations of motion from steady-state flight conditions may be cast in terms of these derivatives. Using these linear equations, transfer functions for the control and navigation systems were developed and feedback control laws based on Proportional, Integral, and Derivative (PID) control design were developed to control the aircraft. The PID gains may then be programmed into the autopilot software and uploaded to the microprocessor of the autopilot. The Pico-Pilot system was flight tested and shown to be successful in navigating a 12-inch MAV through a course defined by a number of waypoints with a high degree of accuracy, and in 20 mph winds. The system, though, showed problems with control authority in the roll and pitch motion of the aircraft: causing oscillations in these directions, but the aircraft maintained its heading while following the prescribed course. Flight tests were performed in remote control mode to evaluate handling, adjust trim, and test data logging for the Zagi with integrated MP2028(sup g). Ground testing was performed to test GPS acquisition, data logging, and control response in autonomous mode. Technical difficulties and integration limitations with the autopilot prevented fully autonomous flight from taking place, but the integration methodologies developed for this autopilot are, in general, applicable for unmanned air vehicles within the 36-inch size class or larger that use a PID control based autopilot.

Platanitis, George; Shkarayev, Sergey

2005-01-01

128

Air pollution and health risks due to vehicle traffic.  

PubMed

Traffic congestion increases vehicle emissions and degrades ambient air quality, and recent studies have shown excess morbidity and mortality for drivers, commuters and individuals living near major roadways. Presently, our understanding of the air pollution impacts from congestion on roads is very limited. This study demonstrates an approach to characterize risks of traffic for on- and near-road populations. Simulation modeling was used to estimate on- and near-road NO2 concentrations and health risks for freeway and arterial scenarios attributable to traffic for different traffic volumes during rush hour periods. The modeling used emission factors from two different models (Comprehensive Modal Emissions Model and Motor Vehicle Emissions Factor Model version 6.2), an empirical traffic speed-volume relationship, the California Line Source Dispersion Model, an empirical NO2-NOx relationship, estimated travel time changes during congestion, and concentration-response relationships from the literature, which give emergency doctor visits, hospital admissions and mortality attributed to NO2 exposure. An incremental analysis, which expresses the change in health risks for small increases in traffic volume, showed non-linear effects. For a freeway, "U" shaped trends of incremental risks were predicted for on-road populations, and incremental risks are flat at low traffic volumes for near-road populations. For an arterial road, incremental risks increased sharply for both on- and near-road populations as traffic increased. These patterns result from changes in emission factors, the NO2-NOx relationship, the travel delay for the on-road population, and the extended duration of rush hour for the near-road population. This study suggests that health risks from congestion are potentially significant, and that additional traffic can significantly increase risks, depending on the type of road and other factors. Further, evaluations of risk associated with congestion must consider travel time, the duration of rush-hour, congestion-specific emission estimates, and uncertainties. PMID:23500830

Zhang, Kai; Batterman, Stuart

2013-04-15

129

Air pollution and health risks due to vehicle traffic  

PubMed Central

Traffic congestion increases vehicle emissions and degrades ambient air quality, and recent studies have shown excess morbidity and mortality for drivers, commuters and individuals living near major roadways. Presently, our understanding of the air pollution impacts from congestion on roads is very limited. This study demonstrates an approach to characterize risks of traffic for on- and near-road populations. Simulation modeling was used to estimate on- and near-road NO2 concentrations and health risks for freeway and arterial scenarios attributable to traffic for different traffic volumes during rush hour periods. The modeling used emission factors from two different models (Comprehensive Modal Emissions Model and Motor Vehicle Emissions Factor Model version 6.2), an empirical traffic speed–volume relationship, the California Line Source Dispersion Model, an empirical NO2–NOx relationship, estimated travel time changes during congestion, and concentration–response relationships from the literature, which give emergency doctor visits, hospital admissions and mortality attributed to NO2 exposure. An incremental analysis, which expresses the change in health risks for small increases in traffic volume, showed non-linear effects. For a freeway, “U” shaped trends of incremental risks were predicted for on-road populations, and incremental risks are flat at low traffic volumes for near-road populations. For an arterial road, incremental risks increased sharply for both on- and near-road populations as traffic increased. These patterns result from changes in emission factors, the NO2–NOx relationship, the travel delay for the on-road population, and the extended duration of rush hour for the near-road population. This study suggests that health risks from congestion are potentially significant, and that additional traffic can significantly increase risks, depending on the type of road and other factors. Further, evaluations of risk associated with congestion must consider travel time, the duration of rush-hour, congestion-specific emission estimates, and uncertainties. PMID:23500830

Zhang, Kai; Batterman, Stuart

2014-01-01

130

Suppressing Vertical Vibration in Railway Vehicles through Air Spring Damping Control  

Microsoft Academic Search

To improve the riding comfort of railway vehicles equipped with the air suspension system now in widespread use, we tested a semi-active air suspension control system with a variable orifice. The system is installed between the air spring and the auxiliary air chamber, and is adjusted using a controller with a design based on the H? control algorithm. We carried

Yoshiki Sugahara; Tadao Takigami; Akihito Kazato

2007-01-01

131

Q-Learning Approach to Automated Unmanned Air Vehicle (UAV) Demining  

E-print Network

) sensor or camera is installed onboard the UAV for the purpose of detecting and classifying multipleQ-Learning Approach to Automated Unmanned Air Vehicle (UAV) Demining Silvia Ferrari and Greyson to Unmanned Air Vehicle (UAV) navigation, or path planning, for sensing applications in which an infrared (IR

Ferrari, Silvia

132

Proposal for a Vehicle Level Test Procedure to Measure Air Conditioning Fuel Use  

Microsoft Academic Search

The air-conditioning (A\\/C) compressor load significantly impacts the fuel economy of conventional vehicles and the fuel use\\/range of plug-in hybrid electric vehicles (PHEV). A National Renewable Energy Laboratory (NREL) vehicle performance analysis shows the operation of the air conditioner reduces the charge depletion range of a 40-mile range PHEV from 18% to 30% in a worst case hot environment. Designing

Rugh

2010-01-01

133

H-CANYON AIR EXHAUST TUNNEL INSPECTION VEHICLE DEVELOPMENT  

SciTech Connect

The H-Canyon at Savannah River Site is a large concrete structure designed for chemical separation processes of radioactive material. The facility requires a large ventilation system to maintain negative pressure in process areas for radioactive contamination control and personnel protection. The ventilation exhaust is directed through a concrete tunnel under the facility which is approximately five feet wide and 8 feet tall that leads to a sand filter and stack. Acidic vapors in the exhaust have had a degrading effect on the surface of the concrete tunnels. Some areas have been inspected; however, the condition of other areas is unknown. Experience from historical inspections with remote controlled vehicles will be discussed along with the current challenge of inspecting levels below available access points. The area of interest in the exhaust tunnel must be accessed through a 14 X 14 inch concrete plug in the floor of the hot gang valve corridor. The purpose for the inspection is to determine the condition of the inside of the air tunnel and establish if there are any structural concerns. Various landmarks, pipe hangers and exposed rebar are used as reference points for the structural engineers when evaluating the current integrity of the air tunnel.

Minichan, R.; Fogle, R.; Marzolf, A.

2011-05-24

134

California's Zero Emission Vehicle Program Cleaner air needed  

E-print Network

also eliminate the evaporative emissions that escape from gasoline vehicles. And, gasoline vehicles-forming gases (ROG+NOx); includes gasoline marketing emissions ** Super Ultra Low Emission Vehicle - cleanest gasoline powered vehicle *** Includes powerplant emissions Studies estimate that EV maintenance will cost

Gille, Sarah T.

135

Full potential flowfield solution of two launch vehicles using TranAir  

NASA Technical Reports Server (NTRS)

Rapid prediction of aerodynamic coefficients is necessary in the early design stages of launch vehicles. One way to do this is by using the transonic full potential code, TranAir. This paper discusses the application of TranAir on launch vehicles with boattails at transonic Mach numbers, to determine aerodynamic coefficients and pressure distributions along the body. Other methods are not readily available for determination of the latter for the purpose of preliminary design. The results are presented showing some capabilities and limitations of TranAir for aerodynamic prediction of launch vehicles. The predictions for TranAir are compared with wind tunnel data for two different configurations.

Ebersohl, J.; Shivananda, T.; Madson, M.

1992-01-01

136

Impact of Solar Control PVB Glass on Vehicle Interior Temperatures, Air-Conditioning Capacity, Fuel Consumption, and Vehicle Range  

SciTech Connect

The objective of the study was to assess the impact of Saflex1 S-series Solar Control PVB (polyvinyl butyral) configurations on conventional vehicle fuel economy and electric vehicle (EV) range. The approach included outdoor vehicle thermal soak testing, RadTherm cool-down analysis, and vehicle simulations. Thermal soak tests were conducted at the National Renewable Energy Laboratory's Vehicle Testing and Integration Facility in Golden, Colorado. The test results quantified interior temperature reductions and were used to generate initial conditions for the RadTherm cool-down analysis. The RadTherm model determined the potential reduction in air-conditioning (A/C) capacity, which was used to calculate the A/C load for the vehicle simulations. The vehicle simulation tool identified the potential reduction in fuel consumption or improvement in EV range between a baseline and modified configurations for the city and highway drive cycles. The thermal analysis determined a potential 4.0% reduction in A/C power for the Saflex Solar PVB solar control configuration. The reduction in A/C power improved the vehicle range of EVs and fuel economy of conventional vehicles and plug-in hybrid electric vehicles.

Rugh, J.; Chaney, L.; Venson, T.; Ramroth, L.; Rose, M.

2013-04-01

137

77 FR 73459 - California State Motor Vehicle Pollution Control Standards; Notice of Waiver of Clean Air Act...  

Federal Register 2010, 2011, 2012, 2013, 2014

...PROTECTION AGENCY [FRL-9759-4] California State Motor Vehicle Pollution Control...Waiver of Clean Air Act Preemption; California's 2010 Model Year Heavy-Duty Vehicle...SUMMARY: EPA has granted the California Air Resources Board (CARB) its...

2012-12-10

138

Seventh International Conference On High-Performance Marine Vehicles  

E-print Network

, deck mounted air fans force air into the plenum and positive air pressure builds. When of the project was to validate a multihull surface effect ship that incorporates a single continuous air cushion Maxsurf and then was further developed in Rhinoceros. The M-SEC concept incorporates an SES air cushion

Wood, Stephen L.

139

21 CFR 872.3540 - OTC denture cushion or pad.  

Code of Federal Regulations, 2011 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3540 OTC denture cushion or pad. (a) Identification. An OTC denture cushion or pad is a...

2011-04-01

140

21 CFR 872.3540 - OTC denture cushion or pad.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3540 OTC denture cushion or pad. (a) Identification. An OTC denture cushion or pad is a...

2013-04-01

141

21 CFR 872.3540 - OTC denture cushion or pad.  

Code of Federal Regulations, 2014 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3540 OTC denture cushion or pad. (a) Identification. An OTC denture cushion or pad is a...

2014-04-01

142

Air Quality Impacts of Some Alternative Vehicle Options UC Irvine National Fuel Cell Research Center 1 March 28, 2008  

E-print Network

Air Quality Impacts of Some Alternative Vehicle Options UC Irvine National Fuel Cell Research Center 1 March 28, 2008 Determining relative air quality impacts of various personal vehicle options of California, Irvine (UCI) #12;Air Quality Impacts of Some Alternative Vehicle Options UC Irvine National Fuel

Dabdub, Donald

143

Dynamics, stability, and control analyses of flapping wing micro-air vehicles  

NASA Astrophysics Data System (ADS)

The paper presents an overview of the various analyses of flight dynamics, stability, and control of flapping wing micro-air vehicles available in the literature. The potential benefits of flapping wing micro-air vehicles for civil, military, and search and rescue operations are numerous. The majority of the flight dynamics research involves the standard aircraft (6DOF) equations of motion, although a growth is evident in examining the multibody flight dynamics models of flapping wing micro-air vehicles. The stability of flapping wing micro-air vehicles is largely studied in the vicinity of hover and forward flight. The majority of stability studies focus on linear, time-invariant stability in the vicinity of reference flight conditions, such as hover or forward flight. The consistent result is that flapping wing micro-air vehicles are unstable in an open loop setting. The unstable result is based on linear and nonlinear stability analyses. Control has been demonstrated for hovering and forward flight through various methods, both linear and nonlinear in nature. The entirety of reported research into the stability and control of flapping wing micro-air vehicles has neglected the mass effects of the wings on the position and orientation of the central body. Successful control of a flapping wing micro-air vehicle, with the wings' mass effects included, is still an open research area.

Orlowski, Christopher T.; Girard, Anouck R.

2012-05-01

144

Transportation vehicle energy intensities. A joint DOT/NASA reference paper. [energy consumption of air and ground vehicles  

NASA Technical Reports Server (NTRS)

A compilation of data on the energy consumption of air and ground vehicles is presented. The ratio BTU/ASM, British Thermal Units/Available Seat Mile, is used to express vehicle energy intensiveness, and related to the energy consumed directly in producing seat-mile or ton-mile productivity. Data is presented on passenger and freight vehicles which are in current use or which are about to enter service, and advanced vehicles which may be operational in the 1980's and beyond. For the advanced vehicles, an estimate is given of the date of initial operational service, and the performance characteristics. Other key considerations in interpreting energy intensiveness for a given mode are discussed, such as: load factors, operations, overhead energy consumption, and energy investments in new structure and equipment.

Mascy, A. C.; Paullin, R. L.

1974-01-01

145

BLDC motor drive system of air-condition of hybrid electric vehicle  

Microsoft Academic Search

Recently the research and development of electric compressor in the electric automobile have being focused on. In HEV (hybrid electric vehicle), the engine is turned off in the case of stop to raise fuel efficiency and prevent air pollution. The conventional air conditioner system which is worked by the engine power through belt connection can't provide cool air to inside

Tae Uk Jung; Sung Ho Lee; Sung Jun Park; Cheol Ho Yun; Yu Tao

2007-01-01

146

Aerial networking communication solutions using Micro Air Vehicle (MAV)  

NASA Astrophysics Data System (ADS)

The application of a Micro Air Vehicle (MAV) for wireless networking is slowly gaining significance in the field of network robotics. Aerial transport of data requires efficient network protocols along with accurate positional adjustment of the MAV to minimize transaction times. In our proof of concept, we develop an Aerial networking protocol for data transfer using the technology of Disruption Tolerant Networks (DTN), a store-and-forward approach for environments that deals with disrupted connectivity. Our results show that close interaction between networking and flight behavior helps in efficient data exchange. Potential applications are in areas where network infrastructure is minimal or unavailable and distances may be large. For example, forwarding video recordings during search and rescue, agriculture, swarm communication, among several others. A practical implementation and validation, as described in this paper, presents the complex dynamics of wireless environments and poses new challenges that are not addressed in earlier work on this topic. Several tests are evaluated in a practical setup to display the networking MAV behavior during such an operation.

Balasubramanian, Shyam; de Graaf, Maurits; Hoekstra, Gerard; Corporaal, Henk; Wijtvliet, Mark; Cuadros Linde, Javier

2014-10-01

147

A Randomized Clinical Trial on Preventing Pressure Ulcers with Wheelchair Seat Cushions  

PubMed Central

Objectives To determine the efficacy of skin protection wheelchair seat cushions in preventing pressure ulcers in the elderly, nursing home population Design Clinical trial with participants assigned at random to either a skin protection or segmented foam cushion. Two hundred thirty two participants were recruited between June 2004 and May 2008 and followed for 6 months or until pressure ulcer incidence. Setting Twelve nursing homes Participants Nursing home residents’ age ? 65, using wheelchairs ?6 hours/day, Braden score ? 18, and combined Braden activity and mobility score ? 5. Participants were recruited from a referred sample. Intervention All participants were provided a fitted wheelchair and randomized into skin protection (SPC) or segmented foam (SFC) cushion groups. The SPC group received an air, viscous fluid/foam, or gel/foam cushion. The SFC group received a 7.6 cm crosscut foam cushion. Measurements Pressure ulcer incidence over 6 months for wounds near the ischial tuberosities (IT ulcers) were measured. Secondary analysis was performed on combined IT and sacral/coccyx ulcers. Results One hundred eighty participants reached a study endpoint and 42 were lost to follow-up. Ten did not receive the intervention. There were 8/119 (6.7%) IT ulcers in the SFC group and 1/113 (0.9%) in the SPC group (p<0.04). In the group of combined IT and sacral/coccyx ulcers, there were 21/119 pressure ulcers (17.6%) in the SFC group and 12/113 (10.6%) in the SPC group (p=0.14). Conclusion Skin protection cushions used with fitted wheelchairs lower pressure ulcer incidence for elderly, nursing home residents and should be used to help prevent pressure ulcers. PMID:21070197

Brienza, David; Kelsey, Sheryl; Karg, Patricia; Allegretti, Ana; Olson, Marian; Schmeler, Mark; Zanca, Jeanne; Geyer, Mary Jo; Kusturiss, Marybeth; Holm, Margo

2010-01-01

148

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...  

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

Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Clean Lubrication Oil Storage Tank & Enclosure, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

149

78 FR 25858 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Motor Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...of Air Quality Implementation Plans; Pennsylvania; Motor Vehicle Emissions Budgets for the Pennsylvania Counties in the Philadelphia-Wilmington, PA-NJ-DE 1997 Fine Particulate Matter Nonattainment Area Correction In rule document 2013-7539...

2013-05-03

150

Co-ordinated Tracking and Planning Using Air and Ground Vehicles  

E-print Network

The MAV ’08 competition in Agra, India focused on the problem of using air and ground vehicles to locate and rescue hostages being held in a remote building. Executing this mission required addressing a number of technical ...

Bachrach, Abraham Galton

151

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...  

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

Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Microwave Equipment Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

152

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...  

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

Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Techinical Equipment Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

153

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...  

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

Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Emergency Generator Enclosure, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

154

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...  

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

Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Supply Warehouse, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

155

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...  

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

Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Electric Substation, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

156

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...  

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

Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Civil Engineering Storage Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

157

78 FR 57501 - Approval and Promulgation of Air Quality Implementation Plans; Wisconsin; Amendments to Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Air Quality Implementation Plans; Wisconsin; Amendments to Vehicle Inspection and Maintenance Program for Wisconsin AGENCY: Environmental Protection Agency...plan (SIP) revision submitted by the Wisconsin Department of Natural Resources...

2013-09-19

158

Design of an adaptive 3-dimensional display enabled by a swarm of autonomous micro air vehicles  

E-print Network

This thesis is motivated by the concept of a system consisting of a swarm of small, automatically controlled air vehicles, each carrying a colour-controlled light source (payload), capable of executing coordinated maneouvres ...

Mueller, Erich, S.M. Massachusetts Institute of Technology

2012-01-01

159

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray Warning ...  

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

Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Satellite Communications Terminal, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

160

Beale Air Force Base, Perimeter Acquisition Vehicle Entry PhasedArray ...  

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

- Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Techinical Equipment Building, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

161

Unmanned air vehicle (UAV) ultra-persitence research  

SciTech Connect

Sandia National Laboratories and Northrop Grumman Corporation Integrated Systems, Unmanned Systems (NGIS UMS) collaborated to further ultra-persistence technologies for unmanned air vehicles (UAVs). The greatest shortfalls in UAV capabilities have been repeatedly identified as (1) insufficient flight persistence or 'hang time,' (2) marginal electrical power for running higher power avionics and payload systems, and (3) inadequate communications bandwidth and reach. NGIS UMS requested support from Sandia to develop an ultra-persistent propulsion and power system (UP3S) for potential incorporation into next generation UAV systems. The team members tried to determine which energy storage and power generation concepts could most effectively push UAV propulsion and electrical power capabilities to increase UAV sortie duration from days to months while increasing available electrical power at least two-fold. Primary research and development areas that were pursued included these goals: perform general system engineering and integration analyses; develop initial thermal and electrical power estimates; provide mass, volume, dimensional, and balance estimates; conduct preliminary safety assessments; assess logistics support requirements; perform, preliminary assessments of any security and safeguards; evaluate options for removal, replacement, and disposition of materials; generally advance the potential of the UP3S concept. The effort contrasted and compared eight heat sources technologies, three power conversion, two dual cycle propulsion system configurations, and a single electrical power generation scheme. Overall performance, specific power parameters, technical complexities, security, safety, and other operational features were successfully investigated. Large and medium sized UAV systems were envisioned and operational flight profiles were developed for each concept. Heat source creation and support challenges for domestic and expeditionary operations were considered. Fundamental cost driver analysis was also performed. System development plans were drafted in order to determine where the technological and programmatic critical paths lay. As a result of this effort, UAVs were to be able to provide far more surveillance time and intelligence information per mission while reducing the high cost of support activities. This technology was intended to create unmatched global capabilities to observe and preempt terrorist and weapon of mass destruction (WMD) activities. Various DOE laboratory and contractor personnel and facilities could have been used to perform detailed engineering, fabrication, assembly and test operations including follow-on operational support. Unfortunately, none of the results will be used in the near-term or mid-term future. NGIS UMS and SNL felt that the technical goals for the project were accomplished. NGIS UMS was quite pleased with the results of analysis and design although it was disappointing to all that the political realities would not allow use of the results. Technology and system designs evaluated under this CRADA had previously never been applied to unmanned air vehicles (UAVs). Based upon logistic support cost predictions, because the UAVs would not have had to refuel as often, forward basing support costs could have been reduced due to a decrease in the number and extent of support systems and personnel being required to operate UAVs in remote areas. Basic application of the advanced propulsion and power approach is well understood and industry now understands the technical, safety, and political issues surrounding implementation of these strategies. However, the overall economic impact was not investigated. The results will not be applied/implemented. No near-term benefit to industry or the taxpayer will be encountered as a result of these studies.

Dron, S. B.

2012-03-01

162

Aerodynamic modelling of insect-like flapping flight for micro air vehicles  

Microsoft Academic Search

Insect-like flapping flight offers a power-efficient and highly manoeuvrable basis for a micro air vehicle capable of indoor flight. The development of such a vehicle requires a careful wing aerodynamic design. This is particularly true since the flapping wings will be responsible for lift, propulsion and manoeuvres, all at the same time. It sets the requirement for an aerodynamic tool

S. A. Ansari; R. ?bikowski; K. Knowles

2006-01-01

163

Coupled Vehicle Design and Network Flow Optimization for Air Transportation Systems  

E-print Network

Coupled Vehicle Design and Network Flow Optimization for Air Transportation Systems Christine: 10.2514/1.27320 Traditionally, the design of a transportation system has focused on either vehicle for a transportation system, it is advantageous to expand the system boundary during the design process to include

de Weck, Olivier L.

164

Fugitive particulate air emissions from off-road vehicle maneuvers at military training lands  

Technology Transfer Automated Retrieval System (TEKTRAN)

Military training lands used for off-road vehicle maneuvers may be subject to severe soil loss and air quality degradation as a result of severe wind erosion. The objective of this study was to measure suspended particulate matter resulting from various different vehicle training scenarios. Soil s...

165

Vehicle cabin air quality monitor using gas sensors for improved safety  

Microsoft Academic Search

A vehicle cabin air quality monitor using carbon monoxide (CO) and oxygen (O2) gas sensors has been designed, developed and on-road tested. The continuous monitoring of oxygen and carbon monoxide provides added vehicle safety as alarms could be set off when dangerous gas concentrations are reached, preventing driver fatigue, drowsiness, and exhaust gas suicides. CO concentrations of 30 ppm and

K. Galatsis; W. Wlodarski; Y. X. Li; K. Kalantar-zadeh

2000-01-01

166

Assessing the Link between Environmental Concerns and Consumers' Decisions to Use Clean-Air Vehicles  

ERIC Educational Resources Information Center

A consulting contract with the California Air Resources Board led to a project examining how California drivers' and fleet managers' perceptions, attitudes, and consumer behavior regarding Clean Vehicle Technologies influenced their own energy choices when it came to purchasing vehicles. The consultants examined archival research, conducted focus…

Plax, Timothy G.; Kearney, Patricia; Ross, Ted J.; Jolly, J. Christopher

2008-01-01

167

Fuel Used for Vehicle Air Conditioning: A State-by-State Thermal Comfort-Based Approach  

Microsoft Academic Search

How much fuel does vehicle air conditioning actually use? This study attempts to answer that question to determine the national and state-by-state fuel use impact seen by using air conditioning in light duty gasoline vehicles. The study used data from US cities, representative of averages over the past 30 years, 1X—see Definitions, the Toyota Prius, the Honda Insight, a 3X

Valerie H. Johnson

168

Control of air pollution from new motor vehicles and new motor vehicle engines. Importation of catalyst-equipped vehicles  

SciTech Connect

The Environmental Protection Agency proposes to amend Subparts A and P, Part 85 of Title 40 which govern the labeling and importation of motor vehicles and motor vehicle engines in order to assure that vehicles equipped with catalytic converters and imported into the United States after having been driven abroad on leaded gasoline are brought into conformity with emission standards. Available information indicates that catalyst-equipped vehicles which have been operated outside of North America will have been fueled with leaded gasoline due to the general unavailability of unleaded gasoline abroad. The Agency proposes that such vehicles be imported under bond. The Agency also plans to institute a publicity program designed to inform the public of the greater convenience inherent in purchasing a vehicle from a manufacturer who has an internal control program as compared to bonding the vehicle with the United States Customs Service.

Quarles, J.

1974-10-21

169

Secondary air control in vehicle exhaust purification system  

SciTech Connect

Control of secondary air flow to a reactor during normal operating condition of an engine is provided by relieving a predetermined portion of the secondary air discharged from an air pump to a point intermediate the reactor and a muffler installed downstream of the reactor. When the engine is operating under heavy load and/or at high speeds, all of the secondary air from the air pump is supplied to the reactor, while when the engine is operating at full load all of the secondary air from the air pump is relieved to the ambient atmosphere.

Takagi, Y.

1980-01-15

170

The promise of air cargo: System aspects and vehicle design  

NASA Technical Reports Server (NTRS)

The current operation of the air cargo system is reviewed. An assessment of the future of air cargo is provided by: (1) analyzing statistics and trends, (2) by noting system problems and inefficiencies, (3) by analyzing characteristics of 'air eligible' commodities, and (4) by showing the promise of new technology for future cargo aircraft with significant improvements in costs and efficiency. The following topics are discussed: (1) air cargo demand forecasts; (2) economics of air cargo transport; (3) the integrated air cargo system; (4) evolution of airfreighter design; and (5) the span distributed load concept.

Whitehead, A. H., Jr.

1976-01-01

171

A method for reducing exhaust pressure of vehicle compressed air powered engine  

Microsoft Academic Search

Compressed air powered engine is a type of zero-pollution engine, but its conversion efficiency is very low for its high pressure exhaust which causes much exergy loss. In this study, a control system was developed to reduce the exhaust pressure of vehicle compressed air powered engine. The control system is made up of a controller, a pressure sensor, a photoelectric

Zhenggang Xu; Xiaopeng Xie

2009-01-01

172

Air quality impacts of motor vehicle emissions in the south coast air basin: Current versus more stringent control scenario  

NASA Astrophysics Data System (ADS)

States are working to comply with the ozone National Ambient Air Quality Standards (NAAQS). Often, regulations restricting vehicle emissions are promulgated in order to attain compliance with the NAAQS. Currently, more stringent vehicle emission regulations are being considered by government agencies. This paper compares emissions from passenger cars and light duty trucks under the current California Low Emission Vehicle (LEV II) standards to a control scenario which was anticipated in 2008 to become LEV III (referred to as "more stringent control" in this paper) and determines if the scenario would result in additional improvements to air quality in California's South Coast Air Basin. The air quality modeling was performed using the Community Multi-scale Air Quality Model (CMAQ) for years 2005, 2014 and 2020. The more stringent control sensitivity study simulated a scenario in which all new passenger cars and light duty trucks in the California South Coast Air Basin in year 2016 achieve Super Ultra-Low Emission Vehicle (SULEV) tail pipe emissions, zero evaporative emissions and more stringent aggressive driving requirements. The total on-road vehicles emissions difference when averaged across the South Coast Air Basin showed the more stringent scenario compared to LEV II to have reductions of 1% for oxides of nitrogen (NO x), 1% for as reactive organic gases (ROG) and 5% for carbon monoxide (CO) in 2030. LEV II modeled ozone levels in the western areas of the basin increased in 2014 and 2020 as compared to 2005, because these areas are VOC-sensitive and the reductions in NO x emissions in these regions are larger than the VOC reductions. In other areas of the South Coast Basin, ozone is reduced by 1.5% or less. The more stringent control scenario modeled levels of ozone have a maximum decrease from LEV II levels by 1% or less in 2014 and 1.5% or less in 2020.

Collet, Susan; Kidokoro, Toru; Sonoda, Yukihiro; Lohman, Kristen; Karamchandani, Prakash; Chen, Shu-Yun; Minoura, Hiroaki

2012-02-01

173

Operator state estimation for adaptive aiding in uninhabited combat air vehicles  

NASA Astrophysics Data System (ADS)

Chris Russell's research, sponsored by the Air Force Research Laboratory Human Effectiveness Directorate, demonstrated significant improvement of mission effectiveness using adaptive automation and the operator's mental workload in Uninhabited Combat Air Vehicle (UCAV) missions. His work is the first example of closing the loop between the human and the machine by using mental workload based on physiological signals from the operator to adapt the system. Implementation of his research is being demonstrated in a variety of applications, including the Uninhabited Combat Air Vehicle control workstation, Tactical Tomahawk Weapons Control System, and the Objective Force Warrior Program.

Russell, Christopher A.

174

Proposal for a Vehicle Level Test Procedure to Measure Air Conditioning Fuel Use  

SciTech Connect

The air-conditioning (A/C) compressor load significantly impacts the fuel economy of conventional vehicles and the fuel use/range of plug-in hybrid electric vehicles (PHEV). A National Renewable Energy Laboratory (NREL) vehicle performance analysis shows the operation of the air conditioner reduces the charge depletion range of a 40-mile range PHEV from 18% to 30% in a worst case hot environment. Designing for air conditioning electrical loads impacts PHEV and electric vehicle (EV) energy storage system size and cost. While automobile manufacturers have climate control procedures to assess A/C performance, and the U.S. EPA has the SCO3 drive cycle to measure indirect A/C emissions, there is no automotive industry consensus on a vehicle level A/C fuel use test procedure. With increasing attention on A/C fuel use due to increased regulatory activities and the development of PHEVs and EVs, a test procedure is needed to accurately assess the impact of climate control loads. A vehicle thermal soak period is recommended, with solar lamps that meet the SCO3 requirements or an alternative heating method such as portable electric heaters. After soaking, the vehicle is operated over repeated drive cycles or at a constant speed until steady-state cabin air temperature is attained. With this method, the cooldown and steady-state A/C fuel use are measured. This method can be run at either different ambient temperatures to provide data for the GREEN-MAC-LCCP model temperature bins or at a single representative ambient temperature. Vehicles with automatic climate systems are allowed to control as designed, while vehicles with manual climate systems are adjusted to approximate expected climate control settings. An A/C off test is also run for all drive profiles. This procedure measures approximate real-world A/C fuel use and assess the impact of thermal load reduction strategies.

Rugh, J. P.

2010-04-01

175

Affordable Flight Demonstration of the GTX Air-Breathing SSTO Vehicle Concept  

NASA Technical Reports Server (NTRS)

The rocket based combined cycle (RBCC) powered single-stage-to-orbit (SSTO) reusable launch vehicle has the potential to significantly reduce the total cost per pound for orbital payload missions. To validate overall system performance, a flight demonstration must be performed. This paper presents an overview of the first phase of a flight demonstration program for the GTX SSTO vehicle concept. Phase 1 will validate the propulsion performance of the vehicle configuration over the supersonic and hypersonic air- breathing portions of the trajectory. The focus and goal of Phase 1 is to demonstrate the integration and performance of the propulsion system flowpath with the vehicle aerodynamics over the air-breathing trajectory. This demonstrator vehicle will have dual mode ramjetkcramjets, which include the inlet, combustor, and nozzle with geometrically scaled aerodynamic surface outer mold lines (OML) defining the forebody, boundary layer diverter, wings, and tail. The primary objective of this study is to demon- strate propulsion system performance and operability including the ram to scram transition, as well as to validate vehicle aerodynamics and propulsion airframe integration. To minimize overall risk and develop ment cost the effort will incorporate proven materials, use existing turbomachinery in the propellant delivery systems, launch from an existing unmanned remote launch facility, and use basic vehicle recovery techniques to minimize control and landing requirements. A second phase would demonstrate propulsion performance across all critical portions of a space launch trajectory (lift off through transition to all-rocket) integrated with flight-like vehicle systems.

Krivanek, Thomas M.; Roche, Joseph M.; Riehl, John P.; Kosareo, Daniel N.

2003-01-01

176

Micro air vehicle motion tracking and aerodynamic modeling  

NASA Astrophysics Data System (ADS)

Aerodynamic performance of small-scale fixed-wing flight is not well understood, and flight data are needed to gain a better understanding of the aerodynamics of micro air vehicles (MAVs) flying at Reynolds numbers between 10,000 and 30,000. Experimental studies have shown the aerodynamic effects of low Reynolds number flow on wings and airfoils, but the amount of work that has been conducted is not extensive and mostly limited to tests in wind and water tunnels. In addition to wind and water tunnel testing, flight characteristics of aircraft can be gathered through flight testing. The small size and low weight of MAVs prevent the use of conventional on-board instrumentation systems, but motion tracking systems that use off-board triangulation can capture flight trajectories (position and attitude) of MAVs with minimal onboard instrumentation. Because captured motion trajectories include minute noise that depends on the aircraft size, the trajectory results were verified in this work using repeatability tests. From the captured glide trajectories, the aerodynamic characteristics of five unpowered aircraft were determined. Test results for the five MAVs showed the forces and moments acting on the aircraft throughout the test flights. In addition, the airspeed, angle of attack, and sideslip angle were also determined from the trajectories. Results for low angles of attack (less than approximately 20 deg) showed the lift, drag, and moment coefficients during nominal gliding flight. For the lift curve, the results showed a linear curve until stall that was generally less than finite wing predictions. The drag curve was well described by a polar. The moment coefficients during the gliding flights were used to determine longitudinal and lateral stability derivatives. The neutral point, weather-vane stability and the dihedral effect showed some variation with different trim speeds (different angles of attack). In the gliding flights, the aerodynamic characteristics exhibited quasi-steady effects caused by small variations in the angle of attack. The quasi-steady effects, or small unsteady effects, caused variations in the aerodynamic characteristics (particularly incrementing the lift curve), and the magnitude of the influence depended on the angle-of-attack rate. In addition to nominal gliding flight, MAVs in general are capable of flying over a wide flight envelope including agile maneuvers such as perching, hovering, deep stall and maneuvering in confined spaces. From the captured motion trajectories, the aerodynamic characteristics during the numerous unsteady flights were gathered without the complexity required for unsteady wind tunnel tests. Experimental results for the MAVs show large flight envelopes that included high angles of attack (on the order of 90 deg) and high angular rates, and the aerodynamic coefficients had dynamic stall hysteresis loops and large values. From the large number of unsteady high angle-of-attack flights, an aerodynamic modeling method was developed and refined for unsteady MAV flight at high angles of attack. The method was based on a separation parameter that depended on the time history of the angle of attack and angle-of-attack rate. The separation parameter accounted for the time lag inherit in the longitudinal characteristics during dynamic maneuvers. The method was applied to three MAVs and showed general agreement with unsteady experimental results and with nominal gliding flight results. The flight tests with the MAVs indicate that modern motion tracking systems are capable of capturing the flight trajectories, and the captured trajectories can be used to determine the aerodynamic characteristics. From the captured trajectories, low Reynolds number MAV flight is explored in both nominal gliding flight and unsteady high angle-of-attack flight. Building on the experimental results, a modeling method for the longitudinal characteristics is developed that is applicable to the full flight envelope.

Uhlig, Daniel V.

177

Valuation of plug-in vehicle life-cycle air emissions and oil displacement benefits.  

PubMed

We assess the economic value of life-cycle air emissions and oil consumption from conventional vehicles, hybrid-electric vehicles (HEVs), plug-in hybrid-electric vehicles (PHEVs), and battery electric vehicles in the US. We find that plug-in vehicles may reduce or increase externality costs relative to grid-independent HEVs, depending largely on greenhouse gas and SO(2) emissions produced during vehicle charging and battery manufacturing. However, even if future marginal damages from emissions of battery and electricity production drop dramatically, the damage reduction potential of plug-in vehicles remains small compared to ownership cost. As such, to offer a socially efficient approach to emissions and oil consumption reduction, lifetime cost of plug-in vehicles must be competitive with HEVs. Current subsidies intended to encourage sales of plug-in vehicles with large capacity battery packs exceed our externality estimates considerably, and taxes that optimally correct for externality damages would not close the gap in ownership cost. In contrast, HEVs and PHEVs with small battery packs reduce externality damages at low (or no) additional cost over their lifetime. Although large battery packs allow vehicles to travel longer distances using electricity instead of gasoline, large packs are more expensive, heavier, and more emissions intensive to produce, with lower utilization factors, greater charging infrastructure requirements, and life-cycle implications that are more sensitive to uncertain, time-sensitive, and location-specific factors. To reduce air emission and oil dependency impacts from passenger vehicles, strategies to promote adoption of HEVs and PHEVs with small battery packs offer more social benefits per dollar spent. PMID:21949359

Michalek, Jeremy J; Chester, Mikhail; Jaramillo, Paulina; Samaras, Constantine; Shiau, Ching-Shin Norman; Lave, Lester B

2011-10-01

178

Valuation of plug-in vehicle life-cycle air emissions and oil displacement benefits  

PubMed Central

We assess the economic value of life-cycle air emissions and oil consumption from conventional vehicles, hybrid-electric vehicles (HEVs), plug-in hybrid-electric vehicles (PHEVs), and battery electric vehicles in the US. We find that plug-in vehicles may reduce or increase externality costs relative to grid-independent HEVs, depending largely on greenhouse gas and SO2 emissions produced during vehicle charging and battery manufacturing. However, even if future marginal damages from emissions of battery and electricity production drop dramatically, the damage reduction potential of plug-in vehicles remains small compared to ownership cost. As such, to offer a socially efficient approach to emissions and oil consumption reduction, lifetime cost of plug-in vehicles must be competitive with HEVs. Current subsidies intended to encourage sales of plug-in vehicles with large capacity battery packs exceed our externality estimates considerably, and taxes that optimally correct for externality damages would not close the gap in ownership cost. In contrast, HEVs and PHEVs with small battery packs reduce externality damages at low (or no) additional cost over their lifetime. Although large battery packs allow vehicles to travel longer distances using electricity instead of gasoline, large packs are more expensive, heavier, and more emissions intensive to produce, with lower utilization factors, greater charging infrastructure requirements, and life-cycle implications that are more sensitive to uncertain, time-sensitive, and location-specific factors. To reduce air emission and oil dependency impacts from passenger vehicles, strategies to promote adoption of HEVs and PHEVs with small battery packs offer more social benefits per dollar spent. PMID:21949359

Michalek, Jeremy J.; Chester, Mikhail; Jaramillo, Paulina; Samaras, Constantine; Shiau, Ching-Shin Norman; Lave, Lester B.

2011-01-01

179

Oldenburg and Pan CO2 as Cushion Gas for CAES 1  

E-print Network

) · Solution-mined salt cavern · 45-74 bar, supply for network of coal plants Compressed air locomotive://web.ead.anl.gov/saltcaverns/overview/index.htm #12;Oldenburg and Pan CO2 as Cushion Gas for CAES 4 State of the Art · Today there are two CAES plants world-wide. · Huntorf, Germany (290 MW, in operation for 30 yrs) · Two solution-mined salt caverns · 48

Eisen, Michael

180

Radar-based detection and identification for miniature air vehicles  

Microsoft Academic Search

It is claimed that Unmanned Aerial Vehicles (UAVs) used for civilian\\/publicdomain applications will be dom- inant in the near future. Compared to UAVs used by the mili- tary, civilian UAVs are often operated by pilots without formal training, and hence they require increased levels of autonomy and intelligence, especially with regard to reducing threats to public safety. UAV integration into

Allistair Moses; Matthew J. Rutherford; Kimon P. Valavanis

2011-01-01

181

Prospects for future hypersonic air-breathing vehicles  

NASA Technical Reports Server (NTRS)

An overview of the technical progress achieved in key areas of hypersonic airbreathing vehicle development is presented. The context for hypersonic applications is discussed with emphasis placed on technology issues and requirements, particularly for propulsion and technology integration. Attention is given to CFD technology which allows the consideration of configurations and extrapolations to flight conditions that cannot be simulated on the ground.

Beach, H. L., Jr.; Blankson, Isaiah M.

1991-01-01

182

STEREO VISUAL SYSTEM FOR AUTONOMOUS AIR VEHICLE NAVIGATION  

E-print Network

the platform used as testbed and experimental setup. Experiments using the ground robot and the helicopter by the visual odometry and the onboard helicopter state estimation. Keywords: autonomous helicopter, vision of aerial vehicles, one of the first stereo sys- tems for an autonomous helicopter documented is described

Doherty, Patrick

183

TOPICAL REVIEW: On mathematical modelling of insect flight dynamics in the context of micro air vehicles  

Microsoft Academic Search

We discuss some aspects of mathematical modelling relevant to the dynamics of insect flight in the context of insect-like flapping-wing micro air vehicles (MAVs). MAVs are small flying vehicles developed to reconnoître in confined spaces. This requires power-efficient, highly-manoeuvrable, low-speed flight with stable hover. All of these attributes are present in insect flight and hence the focus on reproducing the

Rafal Zbikowski; Salman A. Ansari; Kevin Knowles

2006-01-01

184

On mathematical modelling of insect flight dynamics in the context of micro air vehicles  

Microsoft Academic Search

We discuss some aspects of mathematical modelling relevant to the dynamics of insect flight in the context of insect-like flapping-wing micro air vehicles (MAVs). MAVs are small flying vehicles developed to reconnotre in confined spaces. This requires power-efficient, highly-manoeuvrable, low-speed flight with stable hover. All of these attributes are present in insect flight and hence the focus on reproducing the

Rafa? ?bikowski; Salman A Ansari; Kevin Knowles

2006-01-01

185

Combatting urban air pollution through Natural Gas Vehicle (NGV) analysis, testing, and demonstration  

SciTech Connect

Deteriorating urban air quality ranks as a top concern worldwide, since air pollution adversely affects both public health and the environment. The outlook for improving air quality in the world`s megacities need not be bleak, however, The use of natural gas as a transportation fuel can measurably reduce urban pollution levels, mitigating chronic threats to health and the environment. Besides being clean burning, natural gas vehicles (NGVs) are economical to operate and maintain. The current cost of natural gas is lower than that of gasoline. Natural gas also reduces the vehicle`s engine wear and noise level, extends engine life, and decreases engine maintenance. Today, about 700,000 NGVs operate worldwide, the majority of them converted from gasoline or diesel fuel. This article discusses the economic, regulatory and technological issues of concern to the NGV industry.

NONE

1995-03-01

186

Distributed pheromone-based swarming control of unmanned air and ground vehicles for RSTA  

NASA Astrophysics Data System (ADS)

The use of unmanned vehicles in Reconnaissance, Surveillance, and Target Acquisition (RSTA) applications has received considerable attention recently. Cooperating land and air vehicles can support multiple sensor modalities providing pervasive and ubiquitous broad area sensor coverage. However coordination of multiple air and land vehicles serving different mission objectives in a dynamic and complex environment is a challenging problem. Swarm intelligence algorithms, inspired by the mechanisms used in natural systems to coordinate the activities of many entities provide a promising alternative to traditional command and control approaches. This paper describes recent advances in a fully distributed digital pheromone algorithm that has demonstrated its effectiveness in managing the complexity of swarming unmanned systems. The results of a recent demonstration at NASA's Wallops Island of multiple Aerosonde Unmanned Air Vehicles (UAVs) and Pioneer Unmanned Ground Vehicles (UGVs) cooperating in a coordinated RSTA application are discussed. The vehicles were autonomously controlled by the onboard digital pheromone responding to the needs of the automatic target recognition algorithms. UAVs and UGVs controlled by the same pheromone algorithm self-organized to perform total area surveillance, automatic target detection, sensor cueing, and automatic target recognition with no central processing or control and minimal operator input. Complete autonomy adds several safety and fault tolerance requirements which were integrated into the basic pheromone framework. The adaptive algorithms demonstrated the ability to handle some unplanned hardware failures during the demonstration without any human intervention. The paper describes lessons learned and the next steps for this promising technology.

Sauter, John A.; Mathews, Robert S.; Yinger, Andrew; Robinson, Joshua S.; Moody, John; Riddle, Stephanie

2008-04-01

187

Relative Navigation of Air Vehicles Adam M. Fosbury  

E-print Network

. Most applications Aerospace Engineer. Email: afrl.rvsv@kirtland.af.mil. Member AIAA. Professor Directorate, Kirtland Air Force Base, NM 87117 John L. Crassidis University at Buffalo, State University

Crassidis, John L.

188

Seacoaster advanced marine vehicle. Final report  

SciTech Connect

The Seacoaster combines the high efficiencies of Surface Effect Ships (SES) with simple catamaran hull construction. It has blower pressurized air cushions that support some 80-90 percent of displacement and hence the high efficiencies. However, unlike the SES, there are no expensive and high maintenance flexible seals. Each catamaran sidehull has a simple recess molded or built into its underside. Powered blowers direct pressurized air into such recesses and thereby create lifting air cushions. There are no flexible seals of any kind and there is no air cushion between the sidehulls. Extensive towed model tests were conducted that showed the viability of the invention.

Burg, D.

1998-08-18

189

Configuration Studies of Personal Air Vehicles. Personal Air Vehicle and Flying Jeep Concepts: A Commentary on Promising Approaches or What Goes Around Comes Around (About Every Twenty Years)  

NASA Technical Reports Server (NTRS)

The NASA/Langley Personal Air Vehicle (PAV) Exploration (PAVE) and the DARPA (Defense Advanced Research Projects Agency) Dual Air/Road Transportation System (DARTS) projects were established to investigate the feasibility of creating vehicles which could replace, or at the very least augment, personal ground and air transportation schemes. This overall goal implies integrating several technology areas with practical everyday transportation requirements to design a class of vehicles which will achieve the following goals: (1) Vertical, Extremely Short, or Short Takeoff and Landing (VTOL, ESTOL, STOL) capability; (2) Operation at block speeds markedly faster than current combinations of land and air transportation, particularly in critical market areas; (3) Unit cost comparable to current luxury cars and small general aviation aircraft; (4) Excellent reliability; (5) Excellent safety; (6) Ability to integrate with existing land and air transportation systems. The conclusions of these configuration studies are summarized as follows: (1) Creation of the five assigned configurations prompted added explorations, some of which were dead-ends; (2) Some components could be common to all configurations such as avionics and dual-mode suspension schemes; (3) Single-Mode PAVs can be created by removing dual-mode-specific items; (4) Aviation history provided some intriguing starting points, as in what goes around comes around; (5) CTOL (Conventional Take-off and Landing) and STOL dual-mode PAVs look feasible with single-mode PAVs being simplifications of the dual-mode approach; (6) VTOL PAVs will require development; (7) More exotic collapsing mechanisms mechanisms need development; (8) As a teaching tool, PAVs are not yet a well-enough bounded design problem.

Hall, David W.

2001-01-01

190

Segmented tubular cushion springs and spring assembly  

NASA Technical Reports Server (NTRS)

A spring which includes a tube with an elliptical cross section, with the greater axial dimension extending laterally and the lesser axial dimension extending vertically is disclosed. A plurality of cuts in the form of slots passing through most of a wall of the tube extend perpendiculary to a longitudinal axis extending along the tube. An uncut portion of the tube wall extends along the tube for bonding or fastening the tube to a suitable base, such as a bottom of a seat cushion.

Haslim, L. A. (inventor)

1985-01-01

191

Segmented tubular cushion springs and spring assembly  

NASA Technical Reports Server (NTRS)

A spring (10) includes a tube (12) having an elliptical cross section, with the greater axial dimension (22) extending laterally and the lesser axial dimension (24) extending vertically. A plurality of cuts (20) in the form of slots passing through most of a wall of the tube (12) extend perpendicularly to a longitudinal axis (16) extending along the tube (12). An uncut portion (26) of the tube wall extends along the tube (12) for bonding or fastening the tube to a suitable base, such as a bottom (28) of a seat cushion (30).

Haslim, Leonard A. (Inventor)

1988-01-01

192

Fire blocking systems for aircraft seat cushions  

NASA Technical Reports Server (NTRS)

A configuration and method for reducing the flammability of bodies of organic materials that thermally decompose to give flammable gases comprises covering the body with a flexible matrix that catalytically cracks the flammable gases to less flammable species. Optionally, the matrix is covered with a gas impermeable outer layer. In a preferred embodiment, the invention takes the form of an aircraft seat in which the body is a poly(urethane) seat cushion, the matrix is an aramid fabric or felt and the outer layer is an aluminum film.

Parker, J. A.; Kourtides, D. A. (inventors)

1984-01-01

193

Integrated Computational and Experimental Studies of Flapping-wing Micro Air Vehicle Aerodynamics  

Microsoft Academic Search

This paper describes recent research on flapping-wing micro air vehicles, based on insect-like aerodynamics. A combined analytical, experimental and CFD approach is being adopted to understand and design suitable wing aerodynamics and kinematics. The CFD has used the Fluent 6 commercial code together with the grid-generating software Gambit 2; the experiments have been conducted in air and water, using various

K Knowles; P C Wilkins; S A Ansari; R W Zbikowski

194

Validation of a Nonlinear Automotive Seat Cushion Vibration Model  

Microsoft Academic Search

A low-order, lumped parameter model is proposed to describe the vertical vibration compliance of an automotive seat. The model includes nonlinear stiffness and damping effects that mimic the properties exhibited by open cell foams that are commonly used in the construction of an automotive seat cushion. A shaped sandbag was positioned on a seat cushion and vibrated to obtain test

WILLIAM N. PATTEN; JIAN PANG

1998-01-01

195

Negative Poisson's Ratio Foam as Seat Cushion Material  

E-print Network

1 Negative Poisson's Ratio Foam as Seat Cushion Material A. Lowe¶, and R. S. Lakes§ §Department Lakes, R. S. and Lowe, A. "Negative Poisson's ratio foam as seat cushion material",Cellular Polymers, 19. This was done by Lakes (9) and co-workers (10-14) who introduced and studied negative Poisson's ratio foams

Lakes, Roderic

196

Autonomous Soaring for Improved Endurance of a Small Uninhabited Air Vehicle  

NASA Technical Reports Server (NTRS)

A relatively unexplored method to improve the endurance of an autonomous aircraft is to use buoyant plumes of air found in the lower atmosphere called thermals or updrafts. Glider pilots and birds commonly use updrafts to improve range, endurance, or cross-country speed. This report presents a quantitative analysis of a small electric-powered uninhabited air vehicle using updrafts to extend its endurance over a target location. A three-degree-of-freedom simulation of the uninhabited air vehicle was used to determine the yearly effect of updrafts on performance. Surface radiation and rawinsonde balloon measurements taken at Desert Rock, Nevada, were used to determine updraft size, strength, spacing, shape, and maximum height for the simulation. A fixed-width spiral path was used to search for updrafts at the same time as maintaining line-of-sight to the surface target position. Power was used only when the aircraft was flying at the lower-altitude limit in search of updrafts. Results show that an uninhabited air vehicle with a nominal endurance of 2 hours can fly a maximum of 14 hours using updrafts during the summer and a maximum of 8 hours during the winter. The performance benefit and the chance of finding updrafts both depend on what time of day the uninhabited air vehicle is launched. Good endurance and probability of finding updrafts during the year was obtained when the uninhabited air vehicle was launched 30 percent into the daylight hours after sunrise each day. Yearly average endurance was found to be 8.6 hours with these launch times.

Allen, Michael J.

2005-01-01

197

Development of Micro Air Reconnaissance Vehicle as a Test Bed for Advanced Sensors and Electronics  

NASA Technical Reports Server (NTRS)

This paper describes the development of a Micro/Mini Air Reconnaissance Vehicle for advanced sensors and electronics at NASA Langley Research Center over the last year. This vehicle is expected to have a total weight of less than four pounds, a design velocity of 40 mph, an endurance of 15-20 minutes, and a maximum range of 5km. The vehicle has wings that are simple to detach yet retain the correct alignment. The upper fuselage surface has a quick release hatch used to access the interior and also to mount the varying propulsion systems. The sensor suite developed for this vehicle consists of a Pitot-static measurement system for determining air speed, an absolute pressure measurement for determining altitude, magnetic direction measurement, and three orthogonal gyros to determine body angular rates. Swarming GPS-guidance and in-flight maneuvering is discussed, as well as design and installation of some other advance sensors like MEMS microphones, infrared cameras, GPS, humidity sensors, and an ultrasonic sonar sensor. Also low cost, small size, high performance control and navigation system for the Micro Air Vehicle is discussed. At the end, laboratory characterization of different sensors, motors, propellers, and batteries will be discussed.

Shams, Qamar A.; Vranas, Thomas L.; Fox, Robert L.; Kuhn, Theodore R.; Ingham, John; Logan, Michael J.; Barnes, Kevin N.; Guenther, Benjamin F.

2002-01-01

198

Design of an air sampler for a small unmanned aerial vehicle.  

PubMed

In the aftermath of a nuclear accident or malevolent act, it is of paramount importance to have the capability to monitor airborne radioactive substances by collecting air samples. For potentially dangerous missions, the Radiation and Nuclear Safety Authority of Finland (STUK) has developed an air sampler to be used on a small unmanned aerial vehicle. When a Petrianov or Fluoropore filter is used in the sampler and the air velocity is 71 km h(-1), the air flow rate through the filter is 0.73 m(3) h(-1) or 0.23 m(3) h(-1), respectively. The present article introduces the developed air sampler using fluid dynamic simulations and wind tunnel data. The operation of the system was validated by collecting airborne radioactive aerosols from air. PMID:19091809

Peräjärvi, K; Lehtinen, J; Pöllänen, R; Toivonen, H

2008-01-01

199

Enhancing diagnostics through the visualization of air vehicle data [military aircraft  

Microsoft Academic Search

To achieve an affordable system, the JSF is implementing autonomic logistics capability which includes a diagnostics function to review flight collected data and correlate fault event to flight maneuvers. This flight recreation capability provides, for example a maintainer, the capability to recreate a flight based on the data stored by the air vehicle. The recreation of a flight consists of

A. M. Vollebregt; R. C. Ost; J. C. Donker

2003-01-01

200

Design of Dragonfly Micro Air Vehicles at the University of Arizona  

Microsoft Academic Search

A new autonomous micro air vehicle (MAV) system, Dragonfly III, featuring improvements in the airframe aerodynamic design, as well as in the autopilot controls is presented in this design report. An approach for simultaneous aerodynamics and closed-loop control design for MAVs was employed, including wind tunnel experiments, and CFD simulations. The control laws were constructed and validated numerically using a

D. Coopamah; B. Malladi; D. Silin; S. Shkarayev

201

A class of flight trajectories for tracking ground targets with micro air vehicles  

Microsoft Academic Search

In this paper we derive two classes of flight trajectories for tracking ground based objects with micro air vehicles. The first class of flight trajectories, called longitudinal trajectories, consists of switching between clockwise and counter clockwise orbits so that the average velocity of the MAV along the direction of motion is equal to the velocity of the ground target. The

Randal W. Beard

2007-01-01

202

Modelling and PID controller design for a quadrotor unmanned air vehicle  

Microsoft Academic Search

this paper presents the modelling of a four rotor vertical take-off and landing (VTOL) unmanned air vehicle known as the quadrotor aircraft. The paper presents a new model design method for the flight control of an autonomous quad rotor .The paper describes the controller architecture for the quadrotor as well. The dynamic model of the quad-rotor, which is an under

Atheer L. Salih; M. Moghavvemi; Haider A. F. Mohamed; Khalaf Sallom Gaeid

2010-01-01

203

Multisensor 3D tracking for counter small unmanned air vehicles (CSUAV)  

Microsoft Academic Search

A variety of unmanned air vehicles (UAVs) have been developed for both military and civilian use. The typical large UAV is typically state owned, whereas small UAVs (SUAVs) may be in the form of remote controlled aircraft that are widely available. The potential threat of these SUAVs to both the military and civilian populace has led to research efforts to

Juan R. Vasquez; Kyle M. Tarplee; Ellen E. Case; Anne M. Zelnio; Brian D. Rigling

2008-01-01

204

Nano Air Vehicle wing concepts design and experimental study of nano rotor hovering performance  

Microsoft Academic Search

Nano Air Vehicles (NAVs) were proposed as unmanned aerial robots to fulfill the missions in cluster environment. This study designs two types of wing concept as rotary wing and flapping wing for NAV based on the minimum energy loss theory and biologically inspired theory. The hovering performance of the two concepts is compared each other to demonstrate the concept superiority.

Zhen Liu; Min Xu

2010-01-01

205

CRITERIA AND AIR TOXIC EMISSIONS FROM IN-USE, LOW EMISSION VEHICLES (LEVS)  

EPA Science Inventory

The U.S. Environmental Protection Agency implemented a program to identify tailpipe emissions of criteria and air toxic contaminants from in-use, light-duty Low Emission Vehicles (LEVs). EPA recruited twenty-five LEVs in 2002, and measured emissions on a chassis dynamometer usin...

206

Australian Air Breathing Propulsion Research for Hypersonic, Beamed Energy-Propelled Vehicles  

Microsoft Academic Search

A three year laser-propelled vehicle analysis and design investigation has been begun in June, 2009 by Faculty and graduate students at the University of Adelaide under a Grant\\/Cooperative Agreement Award to the University of Adelaide by the Asian Office of Aerospace Research and Development (AOARD). The major objectives of thsis investigation are: (a) development of hypersonic, air breathing ``lightcraft'' with

David Froning

2010-01-01

207

Vision-based Target Geo-location using a Fixed-wing Miniature Air Vehicle  

Microsoft Academic Search

This paper presents a method for determining the GPS location of a ground-based object when imaged from a fixed-wing miniature air vehicle (MAV). Using the pixel lo- cation of the target in an image, with measurements of MAV position and attitude, and camera pose angles, the target is localized in world coordinates. The main contribution of this paper is to

D. Blake Barber; Joshua D. Redding; Timothy W. Mclain; Randal W. Beard; Clark N. Taylor

2006-01-01

208

Vision-guided flight stability and control for micro air vehicles  

Microsoft Academic Search

Substantial progress has been made recently towards design- ing, building and test-flying remotely piloted Micro Air Vehicles (MAVs) and small UAVs. We seek to complement this progress in overcoming the aerodynamic obstacles to flight at very small scales with a vision-guided flight stability and autonomy system , based on a robust horizon detection algorithm. In this paper, we first motivate

Scott M. Ettinger; Michael C. Nechyba; Peter G. Ifju; Martin Waszak

2003-01-01

209

Rehabilitation of the Rocket Vehicle Integration Test Stand at Edwards Air Force Base  

NASA Technical Reports Server (NTRS)

Since initial use in 1958 for the X-15 rocket-powered research airplane, the Rocket Engine Test Facility has proven essential for testing and servicing rocket-powered vehicles at Edwards Air Force Base. For almost two decades, several successful flight-test programs utilized the capability of this facility. The Department of Defense has recently demonstrated a renewed interest in propulsion technology development with the establishment of the National Aerospace Initiative. More recently, the National Aeronautics and Space Administration is undergoing a transformation to realign the organization, focusing on the Vision for Space Exploration. These initiatives provide a clear indication that a very capable ground-test stand at Edwards Air Force Base will be beneficial to support the testing of future access-to-space vehicles. To meet the demand of full integration testing of rocket-powered vehicles, the NASA Dryden Flight Research Center, the Air Force Flight Test Center, and the Air Force Research Laboratory have combined their resources in an effort to restore and upgrade the original X-15 Rocket Engine Test Facility to become the new Rocket Vehicle Integration Test Stand. This report describes the history of the X-15 Rocket Engine Test Facility, discusses the current status of the facility, and summarizes recent efforts to rehabilitate the facility to support potential access-to-space flight-test programs. A summary of the capabilities of the facility is presented and other important issues are discussed.

Jones, Daniel S.; Ray, Ronald J.; Phillips, Paul

2005-01-01

210

Vision-guided flight stability and control for micro air vehicles  

Microsoft Academic Search

Substantial progress has been made recently towards designing, building and test-flying remotely piloted Micro Air Vehicles (MAVs) and small UAVs. We seek to complement this progress in overcoming the aerodynamic obstacles to flight at very small scales with a vision-guided flight stability and autonomy system, based on a robust horizon detection algorithm. In this paper, we first motivate the use

S. M. Ettinger; Michael C. Nechyba; Peter G. Ifju; Martin Waszak

2002-01-01

211

Challenges for micro-scale flapping-wing micro air vehicles  

NASA Astrophysics Data System (ADS)

The challenges for successful flight of insect-scale micro air vehicles encompass basic questions of fabrication, design, propulsion, actuation, control, and power - topics that have in general been answered for larger aircraft. When developing a flying robot on the scale of flies and bees, all hardware must be developed from scratch as there are no "off-the-shelf" sensors, actuators, or microcontrollers that can satisfy the extreme mass and power limitations imposed by such vehicles. Similar challenges exist for fabrication and assembly of the structural and aeromechanical components of insect-scale micro air vehicles that neither macro-scale techniques nor MEMS can adequately solve. With these challenges in mind, this paper presents progress in the essential technologies for micro-scale flapping-wing robots.

Wood, Robert J.; Finio, Benjamin; Karpelson, Michael; Pérez-Arancibia, Nestor O.; Sreetharan, Pratheev; Whitney, John P.

2012-06-01

212

Thermal Performance of Aircraft Polyurethane Seat Cushions  

NASA Technical Reports Server (NTRS)

Aircraft seat materials were evaluated in terms of their thermal performance. The materials were evaluated using (a) thermogravimetric analysis, (b) differential scanning calorimetry, (c) a modified NBS smoke chamber to determine the rate of mass loss and (d) the NASA T-3 apparatus to determine the thermal efficiency. In this paper, the modified NBS smoke chamber will be described in detail since it provided the most conclusive results. The NBS smoke chamber was modified to measure the weight loss of material when exposed to a radiant heat source over the range of 2.5 to 7.5 W/sq cm. This chamber has been utilized to evaluate the thermal performance of various heat blocking layers utilized to protect the polyurethane cushioning foam used in aircraft seats. Various kinds of heat blocking layers were evaluated by monitoring the weight loss of miniature seat cushions when exposed to the radiant heat. The effectiveness of aluminized heat blocking systems was demonstrated when compared to conventional heat blocking layers such as neoprene. All heat blocking systems showed good fire protection capabilities when compared to the state-of-the-art, i.e., wool-nylon over polyurethane foam.

Kourtides, D. A.; Parker, J. A.

1982-01-01

213

Issues in the design of fault tolerant vehicle management systems for next generation unstable air vehicles  

Microsoft Academic Search

The author describes design issues in fault-tolerant vehicle management systems (VMS) for next-generation high-performance aircraft. Unstable aircraft require a highly reliable fault-tolerant computer to perform dynamic compensation of effector surface controls. Next-generation system requirements for system availability and performance will extend the role of flight criticality beyond the flight data sensors and actuation control functions. Additional control systems requiring a

T. D. Gaska

1988-01-01

214

Space Shuttle Solid Rocket Booster decelerator subsystem - Air drop test vehicle/B-52 design  

NASA Technical Reports Server (NTRS)

The air drop development test program for the Space Shuttle Solid Rocket Booster Recovery System required the design of a large drop test vehicle that would meet all the stringent requirements placed on it by structural loads, safety considerations, flight recovery system interfaces, and sequence. The drop test vehicle had to have the capability to test the drogue and the three main parachutes both separately and in the total flight deployment sequence and still be low-cost to fit in a low-budget development program. The design to test large ribbon parachutes to loads of 300,000 pounds required the detailed investigation and integration of several parameters such as carrier aircraft mechanical interface, drop test vehicle ground transportability, impact point ground penetration, salvageability, drop test vehicle intelligence, flight design hardware interfaces, and packaging fidelity.

Runkle, R. E.; Drobnik, R. F.

1979-01-01

215

Geometry Modeling and Adaptive Control of Air-Breathing Hypersonic Vehicles  

NASA Astrophysics Data System (ADS)

Air-breathing hypersonic vehicles have the potential to provide global reach and affordable access to space. Recent technological advancements have made scramjet-powered flight achievable, as evidenced by the successes of the X-43A and X-51A flight test programs over the last decade. Air-breathing hypersonic vehicles present unique modeling and control challenges in large part due to the fact that scramjet propulsion systems are highly integrated into the airframe, resulting in strongly coupled and often unstable dynamics. Additionally, the extreme flight conditions and inability to test fully integrated vehicle systems larger than X-51 before flight leads to inherent uncertainty in hypersonic flight. This thesis presents a means to design vehicle geometries, simulate vehicle dynamics, and develop and analyze control systems for hypersonic vehicles. First, a software tool for generating three-dimensional watertight vehicle surface meshes from simple design parameters is developed. These surface meshes are compatible with existing vehicle analysis tools, with which databases of aerodynamic and propulsive forces and moments can be constructed. A six-degree-of-freedom nonlinear dynamics simulation model which incorporates this data is presented. Inner-loop longitudinal and lateral control systems are designed and analyzed utilizing the simulation model. The first is an output feedback proportional-integral linear controller designed using linear quadratic regulator techniques. The second is a model reference adaptive controller (MRAC) which augments this baseline linear controller with an adaptive element. The performance and robustness of each controller are analyzed through simulated time responses to angle-of-attack and bank angle commands, while various uncertainties are introduced. The MRAC architecture enables the controller to adapt in a nonlinear fashion to deviations from the desired response, allowing for improved tracking performance, stability, and robustness.

Vick, Tyler Joseph

216

Impact of aeroelasticity on propulsion and longitudinal flight dynamics of an air-breathing hypersonic vehicle  

NASA Technical Reports Server (NTRS)

Many air-breathing hypersonic aerospacecraft design concepts incorporate an elongated fuselage forebody acting as the aerodynamic compression surface for a hypersonic combustion module, or scram jet. This highly integrated design approach creates the potential for an unprecedented form of aero-propulsive-elastic interaction in which deflections of the vehicle fuselage give rise to propulsion transients, producing force and moment variations that may adversely impact the rigid body flight dynamics and/or further excite the fuselage bending modes. To investigate the potential for such interactions, a math model was developed which included the longitudinal flight dynamics, propulsion system, and first seven elastic modes of a hypersonic air-breathing vehicle. Perturbation time histories from a simulation incorporating this math model are presented that quantify the propulsive force and moment variations resulting from aeroelastic vehicle deflections. Root locus plots are presented to illustrate the effect of feeding the propulsive perturbations back into the aeroelastic model. A concluding section summarizes the implications of the observed effects for highly integrated hypersonic air-breathing vehicle concepts.

Raney, David L.; Mcminn, John D.; Pototzky, Anthony S.; Wooley, Christine L.

1993-01-01

217

Measurement and modelling of the y-direction apparent mass of sitting human body–cushioned seat system  

Microsoft Academic Search

Laboratory tests were conducted using 13 male subjects seated on a cushioned commercial vehicle driver's seat. The hands gripped a mock-up steering wheel and the subjects were in contact with the lumbar region of the backrest. The accelerations and forces in the y-direction were measured during random lateral whole-body vibration with a frequency range between 0.25 and 30Hz, vibration magnitudes

George Juraj Stein; Peter Múcka; Barbara Hinz; Ralph Blüthner

2009-01-01

218

Cushion System for Multi-Use Child Safety Seat  

NASA Technical Reports Server (NTRS)

A cushion system for use with a child safety seat has a plurality of bladders assembled to form a seat cushion that cooperates with the seat's safety harness. One or more sensors coupled to the safety harness sense tension therein and generate a signal indicative of the tension. Each of the bladders is individually pressurized by a pressurization system to define a support configuration of the seat cushion. The pressurization system is disabled when tension in the safety harness has attained a threshold level.

Dabney, Richard W. (Inventor); Elrod, Susan V. (Inventor)

2007-01-01

219

Cushion system for multi-use child safety seat  

NASA Technical Reports Server (NTRS)

A cushion system for use with a child safety seat has a plurality of bladders assembled to form a seat cushion that cooperates with the seat's safety harness. One or more sensors coupled to the safety harness sense tension therein and generate a signal indicative of the tension. Each of the bladders is individually pressurized by a pressurization system to define a support configuration of the seat cushion. The pressurization system is disabled when tension in the safety harness has attained a threshold level.

Dabney, Richard W. (Inventor); Elrod, Susan V. (Inventor)

2007-01-01

220

Concentrations of air toxics in motor vehicle-dominated environments.  

PubMed

We at the Desert Research Institute (DRI*) measured volatile organic compounds (VOCs), including several mobile-source air toxics (MSATs), particulate matter with a mass mean aerodynamic diameter < or = 2.5 pm (PM2.5), black carbon (BC), nitrogen oxides (NOx), particulate matter (PM), and carbon monoxide (CO) on highways in Los Angeles County during summer and fall 2004, to characterize the diurnal and seasonal variations in measured concentrations related to volume and mix of traffic. Concentrations of on-road pollutants were then compared to corresponding measurements at fixed monitoring sites. The on-road concentrations of CO and MSATs were higher in the morning under stable atmospheric conditions and during periods of higher traffic volumes. In contrast, BC concentrations, measured as particulate light absorption, were higher on truck routes during the midday sampling periods despite more unstable atmospheric conditions. Compared to the measurements at the three near-road sites, the 1-hour averages of on-road BC concentrations were as much as an order of magnitude higher. The peak 1-minute average concentrations were two orders of magnitude higher for BC and were between two and six times higher for PM2.5 mass. The on-road concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) during the summer were 3.5 +/- 0.7 and 1.2 +/- 0.6 times higher during morning and afternoon commuting periods, respectively, compared to annual average 24-hour concentrations measured at air toxic monitoring network sites. These ratios were higher during the fall, with smaller diurnal differences (4.8 +/- 0.7 and 3.9 +/- 0.6 for morning and afternoon commuting periods, respectively). Ratios similar to those for BTEX were obtained for 1,3-butadiene (BD) and styrene. On-road concentrations of formaldehyde and acetaldehyde were up to two times higher than at air toxics monitoring sites, with fall ratios slightly higher than summer ratios. Chemical mass balance (CMB) receptor model calculations attributed the sum of BTEX almost exclusively to gasoline engine exhaust for on-road samples and all but 5% to 10% of the BTEX at the three near-road sites. CMB analysis attributed 46% to 52% (+/- 7) of the ambient total particulate carbon (TC) at the three near-road sites to diesel exhaust and 10% to 17% (+/- 7) to gasoline exhaust; it attributed about 90% of the ambient elemental carbon (EC) concentrations (measured as refractory carbon using the thermal evolution method) to diesel exhaust. Diesel particulate carbon (DPC) concentrations were estimated by multiplying the mean ratio of TC to EC from the source-dominated ambient samples collected on road on Terminal Island (1.30 +/- 0.28), which is located between the Long Beach and Los Angeles ports, with the measured ambient EC concentrations at the three near-road sites. DPC estimates from EC measurements correlate well with the diesel source contributions calculated with the CMB model. The indication from these apportionments that BC or EC is a good surrogate for diesel exhaust is further supported by the positive correlation of on-road BC concentrations with volumes of truck traffic. Traffic counts have been used in past health assessment studies as surrogates for estimating near-road exposure concentrations with appropriate weighting for proximity to the road. However, the results of this study show that it is necessary to account for the proportion of diesel trucks to total vehicular traffic because of the disproportionate contribution of diesel exhaust to BC and to directly emitted PM. Alternatively, easily measured pollutants such as CO and BC can serve as reasonable surrogates for MSATs (e.g., BTEX and BD) and DPC, respectively. Measuring CO and BC is a reasonably cost-effective approach to quantifying hot-spot exposure concentrations of MSATs that is perhaps more accurate than what is possible using only data from regional air quality monitoring stations or air quality modeling results. PMID:21608416

Fujita, Eric M; Campbell, David E; Zielinska, Barbara; Arnott, William P; Chow, Judith C

2011-02-01

221

Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.  

PubMed

Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario). PMID:19943683

Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

2009-12-01

222

77 FR 50969 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Low Emission Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...and medium-duty vehicles having a gross vehicle weight rating (GVWR...Federal and California vehicle emission standards? Vehicles sold in the United...light and medium duty vehicles. California's vehicle emission...

2012-08-23

223

Orbit-on-demand vehicle propelled by air-turborocket/ramjet engines  

NASA Technical Reports Server (NTRS)

A preliminary design study has been completed for a fully reusable, single-stage-to-orbit transatmospheric vehicle. The specified mission capability was to lift a 20,000 lb payload to low earth orbit. A ground accelerator-assisted horizontal take-off was chosen to increase operational flexibility. The multi-mode propulsion system included the use of air-turborocket, ramjet, scramjet and rocket engines. Weight and performance estimates were obtained for the vehicle. A computer package was developed to perform aerothermodynamic analyses of the propulsion modes throughout the flight environment from take-off to low earth orbit. Results are presented for a semi-optimized trajectory. The analysis indicates that a vehicle of this type has great potential for providing low cost, flexible access to space.

Hartung, L.; Karkow, J.; Ordway, W.; Pickett, D.; Muras, A.

1986-01-01

224

Cleaning the air and improving health with hydrogen fuel-cell vehicles.  

PubMed

Converting all U.S. onroad vehicles to hydrogen fuel-cell vehicles (HFCVs) may improve air quality, health, and climate significantly, whether the hydrogen is produced by steam reforming of natural gas, wind electrolysis, or coal gasification. Most benefits would result from eliminating current vehicle exhaust. Wind and natural gas HFCVs offer the greatest potential health benefits and could save 3700 to 6400 U.S. lives annually. Wind HFCVs should benefit climate most. An all-HFCV fleet would hardly affect tropospheric water vapor concentrations. Conversion to coal HFCVs may improve health but would damage climate more than fossil/electric hybrids. The real cost of hydrogen from wind electrolysis may be below that of U.S. gasoline. PMID:15976300

Jacobson, M Z; Colella, W G; Golden, D M

2005-06-24

225

Cleaning the Air and Improving Health with Hydrogen Fuel-Cell Vehicles  

NASA Astrophysics Data System (ADS)

Converting all U.S. onroad vehicles to hydrogen fuel-cell vehicles (HFCVs) may improve air quality, health, and climate significantly, whether the hydrogen is produced by steam reforming of natural gas, wind electrolysis, or coal gasification. Most benefits would result from eliminating current vehicle exhaust. Wind and natural gas HFCVs offer the greatest potential health benefits and could save 3700 to 6400 U.S. lives annually. Wind HFCVs should benefit climate most. An all-HFCV fleet would hardly affect tropospheric water vapor concentrations. Conversion to coal HFCVs may improve health but would damage climate more than fossil/electric hybrids. The real cost of hydrogen from wind electrolysis may be below that of U.S. gasoline.

Jacobson, M. Z.; Colella, W. G.; Golden, D. M.

2005-06-01

226

The Digital Twin Paradigm for Future NASA and U.S. Air Force Vehicles  

NASA Technical Reports Server (NTRS)

Future generations of NASA and U.S. Air Force vehicles will require lighter mass while being subjected to higher loads and more extreme service conditions over longer time periods than the present generation. Current approaches for certification, fleet management and sustainment are largely based on statistical distributions of material properties, heuristic design philosophies, physical testing and assumed similitude between testing and operational conditions and will likely be unable to address these extreme requirements. To address the shortcomings of conventional approaches, a fundamental paradigm shift is needed. This paradigm shift, the Digital Twin, integrates ultra-high fidelity simulation with the vehicle s on-board integrated vehicle health management system, maintenance history and all available historical and fleet data to mirror the life of its flying twin and enable unprecedented levels of safety and reliability.

Glaessgen, Edward H.; Stargel, D. S.

2012-01-01

227

An Air-Breathing Launch Vehicle Concept for Single-Stage-to-Orbit  

NASA Technical Reports Server (NTRS)

The "Trailblazer" is a 300-lb payload, single-stage-to-orbit launch vehicle concept that uses air-breathing propulsion to reduce the required propellant fraction. The integration of air-breathing propulsion is done considering performance, structural and volumetric efficiency, complexity, and design risk. The resulting configuration is intended to be viable using near-term materials and structures. The aeropropulsion performance goal for the Trailblazer launch vehicle is an equivalent effective specific impulse (I*) of 500 sec. Preliminary analysis shows that this requires flight in the atmosphere to about Mach 10, and that the gross lift-off weight is 130,000 lb. The Trailblazer configuration and proposed propulsion system operating modes are described. Preliminary performance results are presented, and key technical issues are highlighted. An overview of the proposed program plan is given.

Trefny, Charles J.

1999-01-01

228

A Predictive Model for Vehicle Air Exchange Rates based on a Large, Representative Sample  

PubMed Central

The in-vehicle microenvironment is an important route of exposure to traffic-related pollutants, particularly ultrafine particles. However, significant particle losses can occur under conditions of low air exchange rate (AER) when windows are closed and air is recirculating. AERs are lower for newer vehicles and at lower speeds. Despite the importance of AER in affecting in-vehicle particle exposures, few studies have characterized AER and all have tested only a small number of cars. One reason for this is the difficulty in measuring AER with tracer gases such as SF6 the most common method. We developed a simplified yet accurate method for determining AER using the occupants’ own production of CO2 a convenient compound to measure. By measuring initial CO2 build-up rates and equilibrium values of CO2 at fixed speeds, AER was calculated for 59 vehicles representative of California’s fleet. AER measurements correlated and agreed well with the largest other study conducted (R2=0.83). Multi-variable models captured 70% of the variability in observed AER using only age, mileage, manufacturer and speed. These results will be useful to exposure and epidemiological studies since all model variable values are easily obtainable through questionnaire. PMID:21428392

Fruin, Scott A.; Hudda, Neelakshi; Sioutas, Constantinos; Delfino, Ralph J.

2014-01-01

229

Emissions of halocarbons from mobile vehicle air conditioning system in Hong Kong.  

PubMed

During the implementation of Montreal Protocol, emission inventories of halocarbons in different sectors at regional scale are fundamental to the formulation of relevant management strategy and inspection of the implementation efficiency. This study investigated the emission profile of halocarbons used in the mobile vehicle air conditioning system, the leading sector of refrigeration industry in terms of the refrigerant bank, market and emission, in the Hong Kong Special Administrative Region, using a bottom-up approach developed by 2006 IPCC Good Practice Guidance. The results showed that emissions of CFC-12 peaked at 53 tons ODP (Ozone Depletion Potential) in 1992 and then gradually diminished, whereas HFC-134a presented an increasing emission trend since 1990s and the emissions of HFC-134a reached 65,000 tons CO2-equivelant (CO2-eq) by the end of 2011. Uncertainty analysis revealed relatively high levels of uncertainties for special-purpose vehicles and government vehicles. Moreover, greenhouse gas (GHG) abatements under different scenarios indicated that potential emission reduction of HFC-134a ranged from 4.1 to 8.4 × 10(5)tons CO2-eq. The findings in this study advance our knowledge of halocarbon emissions from mobile vehicle air conditioning system in Hong Kong. PMID:24997256

Yan, H H; Guo, H; Ou, J M

2014-08-15

230

Optimum Aeroelastic Design of Resonance Type Flapping Wing for Micro Air Vehicles  

NASA Astrophysics Data System (ADS)

The optimum aeroelastic design method for a resonance-type flapping wing for a Micro Air Vehicle (MAV) is presented. It uses Complex Method and 3D Navier-Stokes code to determine the optimum structural and aerodynamic parameters of a 2 DOF flapping wing system. The method is used to design a dragonfly-type MAV, and numerical simulation shows that the designed flapping wings can generate sufficient lift to sustain the weight and sufficient thrust to overcome the body drag.

Isogai, Koji; Kamisawa, Yuichi; Sato, Hiroyuki

231

Concurrent trajectory and conceptual vehicle design optimization of an aerobatic air race aircraft  

NASA Astrophysics Data System (ADS)

This paper deals with the development of a framework for the concurrent optimization of trajectory and conceptual vehicle design. The tool is applied to the design of an aerobatic air race aircraft that is required to fly a prescribed slalom course consisting of inflatable pylons in the fastest possible time. It is shown that when the aircraft design is tailored to the characteristics of the race track, an improvement in the lap time of about 1 percent can be achieved.

Visser, Hendrikus G.; Liem, Christiaan

2014-10-01

232

Fundamental understanding of the cycloidal-rotor concept for micro air vehicle applications  

Microsoft Academic Search

The cycloidal-rotor (cyclorotor) is a revolutionary flying concept which has not been systematically studied in the past. Therefore, in the current research, the viability of the cyclorotor concept for powering a hover-capable micro-air-vehicle (MAV) was examined through both experiments and analysis. Experimental study included both performance and flow field measurements on a cyclorotor of span and diameter equal to 6

Benedict Moble

2010-01-01

233

The system integration and verification testing of an orbital maneuvering vehicle for an air bearing floor  

NASA Technical Reports Server (NTRS)

The teleoperator and Robotics Evaluation Facility (TOREF) is composed of a 4,000 square foot precision air bearing floor, the Teleoperator Motion Base, the Target Motion and Support Simulator, the mock-ups of the Hubble Space Telescope, Multi-mission Modular Spacecraft, and the Orbital Maneuvering Vehicle (OMV). The TOREF and its general capabilities to support the OMV and other remote system simulations; the facility operating procedures and requirements; and the results of generic OMV investigations are summarized.

Shields, N. L., Jr.; Martin, M. F.; Paulukaitis, K. R.; Haslam, J. W., Jr.; Henderson, D. E.

1986-01-01

234

Flexible Wing Base Micro Aerial Vehicles: Towards Flight Autonomy: Vision-Based Horizon Detection for Micro Air Vehicles  

NASA Technical Reports Server (NTRS)

Recently substantial progress has been made towards design building and testifying remotely piloted Micro Air Vehicles (MAVs). This progress in overcoming the aerodynamic obstacles to flight at very small scales has, unfortunately, not been matched by similar progress in autonomous MAV flight. Thus, we propose a robust, vision-based horizon detection algorithm as the first step towards autonomous MAVs. In this paper, we first motivate the use of computer vision for the horizon detection task by examining the flight of birds (biological MAVs) and considering other practical factors. We then describe our vision-based horizon detection algorithm, which has been demonstrated at 30 Hz with over 99.9% correct horizon identification, over terrain that includes roads, buildings large and small, meadows, wooded areas, and a lake. We conclude with some sample horizon detection results and preview a companion paper, where the work discussed here forms the core of a complete autonomous flight stability system.

Nechyba, Michael C.; Ettinger, Scott M.; Ifju, Peter G.; Wazak, Martin

2002-01-01

235

Plume-based analysis of vehicle fleet air pollutant emissions and the contribution from high emitters  

NASA Astrophysics Data System (ADS)

An automated identification and integration method has been developed to investigate in-use vehicle emissions under real-world conditions. This technique was applied to high time resolution air pollutant measurements of in-use vehicle emissions performed under real-world conditions at a near-road monitoring station in Toronto, Canada during four seasons, through month-long campaigns in 2013-2014. Based on carbon dioxide measurements, over 100 000 vehicle-related plumes were automatically identified and fuel-based emission factors for nitrogen oxides; carbon monoxide; particle number, black carbon; benzene, toluene, ethylbenzene, and xylenes (BTEX); and methanol were determined for each plume. Thus the automated identification enabled the measurement of an unprecedented number of plumes and pollutants over an extended duration. Emission factors for volatile organic compounds were also measured roadside for the first time using a proton transfer reaction time-of-flight mass spectrometer; this instrument provided the time resolution required for the plume capture technique. Mean emission factors were characteristic of the light-duty gasoline dominated vehicle fleet present at the measurement site, with mean black carbon and particle number emission factors of 35 mg kg-1 and 7.7 × 1014 kg-1, respectively. The use of the plume-by-plume analysis enabled isolation of vehicle emissions, and the elucidation of co-emitted pollutants from similar vehicle types, variability of emissions across the fleet, and the relative contribution from heavy emitters. It was found that a small proportion of the fleet (< 25%) contributed significantly to total fleet emissions; 95, 93, 76, and 75% for black carbon, carbon monoxide, BTEX, and particle number, respectively. Emission factors of a single pollutant may help classify a vehicle as a high emitter. However, regulatory strategies to more efficiently target multi-pollutants mixtures may be better developed by considering the co-emitted pollutants as well.

Wang, J. M.; Jeong, C.-H.; Zimmerman, N.; Healy, R. M.; Wang, D. K.; Ke, F.; Evans, G. J.

2015-03-01

236

AirCRED : the rationale and structure of a tool for estimating air pollutant reduction credits for alternative fuel vehicles.  

SciTech Connect

Primarily to assist the U.S. Department of Energy's Clean Cities coalitions in estimating the net benefits of reducing air pollutant emissions gained by acquiring original equipment manufacture (OEM) alternativefuel vehicles (AFVs), Argonne National Laboratory has developed a graphical user interface-based benefit calculation model called AirCred. The application of this modeling tool has been extended to the estimation of state implementation plan credits for AFVs that may be claimed in nonattainment and maintenance regions for ozone and carbon monoxide. The tool also has been approved for and applied to the quantification of projected program benefits in applications for grant support to purchase OEM AFVs under the U.S. Department of Transportation's Congestion Mitigation and Air Quality Program. First, the model's founding principles and relatively simple mechanics are presented, accompanied by graphic displays of data input screens and comparative results for various vehicular categories. Current and future plans are cited for enhancement of the tool, including its respecification for consistency with MOBILE6 and for air planning in the yet-to-be-designated nonattainment areas for ambient particulate matter of 2.5 {mu}m and smaller. Then some issues and controversies about how and where AirCred should be applied are chronicled. Finally, some example applications are presented to illustrate the residual benefits of AFVs over time relative to their conventionally fueled counterparts of the same (recent) model year. Results indicate that AFVs of certain categories will remain viable and attractive candidates for reducing air emissions in ozone and carbon monoxide air quality control regions well into the future.

Saricks, C. L.; Energy Systems

2002-01-01

237

Computer program development specification for the air traffic control subsystem of the Man-Vehicle Systems Research Facility.  

E-print Network

Functional summary: The Air Traffic Control (ATC) Subsystem of the Man-Vehicle System Research Facility (MVSRF) is a hardware/software complex which provides the MVSRF with the capability of simulating the multi-aircraft, ...

Massachusetts Institute of Technology. Flight Transportation Laboratory

1982-01-01

238

Air quality and climate impacts due to CNG conversion of motor vehicles in Dhaka, Bangladesh.  

PubMed

Dhaka had recently experienced rapid conversion of its motor vehicle fleet to run on compressed natural gas (CNG). This paper quantifies ex-post the air quality and climate benefits of the CNG conversion policy, including monetary valuations, through an impact pathway approach. Around 2045 (1665) avoided premature deaths in greater Dhaka (City Corporation) can be attributed to air quality improvements from the CNG conversion policy in 2010, resulting in a saving of around USD 400 million. Majority of these health benefits resulted from the conversion of high-emitting diesel vehicles. CNG conversion was clearly detrimental from climate change perspective using the changes in CO2 and CH4 only (CH4 emissions increased); however, after considering other global pollutants (especially black carbon), the climate impact was ambiguous. Uncertainty assessment using input distributions and Monte Carlo simulation along with a sensitivity analysis show that large uncertainties remain for climate impacts. For our most likely estimate, there were some climate costs, valued at USD 17.7 million, which is an order of magnitude smaller than the air quality benefits. This indicates that such policies can and should be undertaken on the grounds of improving local air pollution alone and that precautions should be taken to reduce the potentially unintended increases in GHG emissions or other unintended effects. PMID:24195736

Wadud, Zia; Khan, Tanzila

2013-12-17

239

Landing Characteristics of a Re-entry Vehicle with Canted Multiple Air Bag Load Alleviation System  

NASA Technical Reports Server (NTRS)

Investigation of the Landing Characteristics of a Re-entry Vehicle Having a Canted Multiple Air Bag Load Alleviation System. An investigation was made to determine the landing-impact characteristics of a reentry vehicle having a multiple-air-bag load-alleviation system. A 1/16-scale dynamic model having four canted air bags was tested at flight-path angles of 90 degrees (vertical), 45 degrees, and 27 degrees for a parachute or paraglider vertical letdown velocity of 30 feet per second (full scale). Landings were made on concrete at attitudes ranging from -l5 degrees to 20 degrees. The friction coefficient between the model heat shield and the concrete was approximately 0.4. An aluminum diaphragm, designed to rupture at 10.8 pounds per square inch gage, was used to maintain initial pressure in the air bags for a short time period. [Entire movie available on DVD from CASI as Doc ID 20070030986. Contact help@sti.nasa.gov

1963-01-01

240

Improving the accuracy of vehicle emissions profiles for urban transportation greenhouse gas and air pollution inventories.  

PubMed

Metropolitan greenhouse gas and air emissions inventories can better account for the variability in vehicle movement, fleet composition, and infrastructure that exists within and between regions, to develop more accurate information for environmental goals. With emerging access to high quality data, new methods are needed for informing transportation emissions assessment practitioners of the relevant vehicle and infrastructure characteristics that should be prioritized in modeling to improve the accuracy of inventories. The sensitivity of light and heavy-duty vehicle greenhouse gas (GHG) and conventional air pollutant (CAP) emissions to speed, weight, age, and roadway gradient are examined with second-by-second velocity profiles on freeway and arterial roads under free-flow and congestion scenarios. By creating upper and lower bounds for each factor, the potential variability which could exist in transportation emissions assessments is estimated. When comparing the effects of changes in these characteristics across U.S. cities against average characteristics of the U.S. fleet and infrastructure, significant variability in emissions is found to exist. GHGs from light-duty vehicles could vary by -2%-11% and CAP by -47%-228% when compared to the baseline. For heavy-duty vehicles, the variability is -21%-55% and -32%-174%, respectively. The results show that cities should more aggressively pursue the integration of emerging big data into regional transportation emissions modeling, and the integration of these data is likely to impact GHG and CAP inventories and how aggressively policies should be implemented to meet reductions. A web-tool is developed to aide cities in improving emissions uncertainty. PMID:25438089

Reyna, Janet L; Chester, Mikhail V; Ahn, Soyoung; Fraser, Andrew M

2015-01-01

241

High Altitude Long Endurance Air Vehicle Analysis of Alternatives and Technology Requirements Development  

NASA Technical Reports Server (NTRS)

The objective of this study was to develop a variety of High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV) conceptual designs for two operationally useful missions (hurricane science and communications relay) and compare their performance and cost characteristics. Sixteen potential HALE UAV configurations were initially developed, including heavier-than-air (HTA) and lighter-than-air (LTA) concepts with both consumable fuel and solar regenerative (SR) propulsion systems. Through an Analysis of Alternatives (AoA) down select process, the two leading consumable fuel configurations (one each from the HTA and LTA alternatives) and an HTA SR configuration were selected for further analysis. Cost effectiveness analysis of the consumable fuel configurations revealed that simply maximizing vehicle endurance can lead to a sub-optimum system solution. An LTA concept with a hybrid propulsion system (solar arrays and a hydrogen-air proton exchange membrane fuel cell) was found to have the best mission performance; however, an HTA diesel-fueled wing-body-tail configuration emerged as the preferred consumable fuel concept because of the large size and technical risk of the LTA concept. The baseline missions could not be performed by even the best HTA SR concept. Mission and SR technology trade studies were conducted to enhance understanding of the potential capabilities of such a vehicle. With near-term technology SR-powered HTA vehicles are limited to operation in favorable solar conditions, such as the long days and short nights of summer at higher latitudes. Energy storage system specific energy and solar cell efficiency were found to be the key technology areas for enhancing HTA SR performance.

Nickol, Craig L.; Guynn, Mark D.; Kohout, Lisa L.; Ozoroski, Thomas A.

2007-01-01

242

76 FR 17487 - Protection of Stratospheric Ozone: New Substitute in the Motor Vehicle Air Conditioning Sector...  

Federal Register 2010, 2011, 2012, 2013, 2014

...million passenger vehicles and typical vehicle operation of...passenger inside a vehicle would at worst...million passenger vehicles in the U.S...hours per year per vehicle, a risk of 4...years for all drivers in the...

2011-03-29

243

In-vehicle exposures to particulate air pollution in Canadian metropolitan areas: the urban transportation exposure study.  

PubMed

Commuters may be exposed to increased levels of traffic-related air pollution owing to close proximity to traffic-emissions. We collected in-vehicle and roof-top air pollution measurements over 238 commutes in Montreal, Toronto, and Vancouver, Canada between 2010 and 2013. Voice recordings were used to collect real-time information on traffic density and the presence of diesel vehicles and multivariable linear regression models were used to estimate the impact of these factors on in-vehicle pollutant concentrations (and indoor/outdoor ratios) along with parameters for road type, land use, and meteorology. In-vehicle PM2.5 and NO2 concentrations consistently exceeded regional outdoor levels and each unit increase in the rate of encountering diesel vehicles (count/min) was associated with substantial increases (>100%) in in-vehicle concentrations of ultrafine particles (UFPs), black carbon, and PM2.5 as well as strong increases (>15%) in indoor/outdoor ratios. A model based on meteorology and the length of highway roads within a 500 m buffer explained 53% of the variation in in-vehicle UFPs; however, models for PM2.5 (R(2) = 0.24) and black carbon (R(2) = 0.30) did not perform as well. Our findings suggest that vehicle commuters experience increased exposure to air pollutants and that traffic characteristics, land use, road types, and meteorology are important determinants of these exposures. PMID:25469563

Weichenthal, Scott; Van Ryswyk, Keith; Kulka, Ryan; Sun, Liu; Wallace, Lance; Joseph, Lawrence

2015-01-01

244

Spatially- and Temporally-Resolved Measurements of Roadway Air Pollution Using a Zero-Emission Electric Vehicle  

EPA Science Inventory

Vehicle-related air pollution has an intrinsically dynamic nature. Recent field measurements and modeling work have demonstrated that near-road topography may modify levels of air pollutants reaching populations residing and working in close proximity to roadways. However, the ma...

245

Survey of Aerothermodynamics Facilities Useful for the Design of Hypersonic Vehicles Using Air-Breathing Propulsion  

NASA Technical Reports Server (NTRS)

This paper surveys the use of aerothermodynamic facilities which have been useful in the study of external flows and propulsion aspects of hypersonic, air-breathing vehicles. While the paper is not a survey of all facilities, it covers the utility of shock tunnels and conventional hypersonic blow-down facilities which have been used for hypersonic air-breather studies. The problems confronting researchers in the field of aerothermodynamics are outlined. Results from the T5 GALCIT tunnel for the shock-on lip problem are outlined. Experiments on combustors and short expansion nozzles using the semi-free jet method have been conducted in large shock tunnels. An example which employed the NASA Ames 16-Inch shock tunnel is outlined, and the philosophy of the test technique is described. Conventional blow-down hypersonic wind tunnels are quite useful in hypersonic air-breathing studies. Results from an expansion ramp experiment, simulating the nozzle on a hypersonic air-breather from the NASA Ames 3.5 Foot Hypersonic wind tunnel are summarized. Similar work on expansion nozzles conducted in the NASA Langley hypersonic wind tunnel complex is cited. Free-jet air-frame propulsion integration and configuration stability experiments conducted at Langley in the hypersonic wind tunnel complex on a small generic model are also summarized.

Arnold, James O.; Deiwert, George S.

1997-01-01

246

An experimental study of a bio-inspired corrugated airfoil for micro air vehicle applications  

Microsoft Academic Search

An experimental study was conducted to investigate the aerodynamic characteristics of a bio-inspired corrugated airfoil compared\\u000a with a smooth-surfaced airfoil and a flat plate at the chord Reynolds number of Re\\u000a C\\u000a  = 58,000–125,000 to explore the potential applications of such bio-inspired corrugated airfoils for micro air vehicle designs.\\u000a In addition to measuring the aerodynamic lift and drag forces acting on

Jeffery T. Murphy; Hui Hu

2010-01-01

247

Design of an airborne launch vehicle for an air launched space booster  

NASA Technical Reports Server (NTRS)

A conceptual design is presented for a carrier vehicle for an air launched space booster. This airplane is capable of carrying a 500,000 pound satellite launch system to an altitude over 40,000 feet for launch. The airplane features a twin fuselage configuration for improved payload and landing gear integration, a high aspect ratio wing for maneuverability at altitude, and is powered by six General Electric GE-90 engines. The analysis methods used and the systems employed in the airplane are discussed. Launch costs are expected to be competitive with existing launch systems.

Chao, Chin; Choi, Rich; Cohen, Scott; Dumont, Brian; Gibin, Mauricius; Jorden, Rob; Poth, Stefan

1993-01-01

248

Model Update of a Micro Air Vehicle (MAV) Flexible Wing Frame with Uncertainty Quantification  

NASA Technical Reports Server (NTRS)

This paper describes a procedure to update parameters in the finite element model of a Micro Air Vehicle (MAV) to improve displacement predictions under aerodynamics loads. Because of fabrication, materials, and geometric uncertainties, a statistical approach combined with Multidisciplinary Design Optimization (MDO) is used to modify key model parameters. Static test data collected using photogrammetry are used to correlate with model predictions. Results show significant improvements in model predictions after parameters are updated; however, computed probabilities values indicate low confidence in updated values and/or model structure errors. Lessons learned in the areas of wing design, test procedures, modeling approaches with geometric nonlinearities, and uncertainties quantification are all documented.

Reaves, Mercedes C.; Horta, Lucas G.; Waszak, Martin R.; Morgan, Benjamin G.

2004-01-01

249

Abstract--The need for intelligent unmanned vehicles has been steadily increasing. These vehicles could be air-, ground-, space-,  

E-print Network

artificial intelligence. In building intelligent systems software for mobile robots or unmanned vehicles1 Abstract--The need for intelligent unmanned vehicles has been steadily increasing. These vehicles capabilities for both civilian and military applications, but much work remains to develop intelligent systems

250

High resolution modeling of the effects of alternative fuels use on urban air quality: Introduction of natural gas vehicles in Barcelona and Madrid Greater Areas (Spain)  

Microsoft Academic Search

The mitigation of the effects of on-road traffic emissions on urban air pollution is currently an environmental challenge. Air quality modeling has become a powerful tool to design environment-related strategies. A wide range of options is being proposed; such as the introduction of natural gas vehicles (NGV), biofuels or hydrogen vehicles. The impacts on air quality of introducing specific NGV

María Gonçalves; Pedro Jiménez-Guerrero; José M. Baldasano

2009-01-01

251

Flexible Wing Base Micro Aerial Vehicles: Vision-Guided Flight Stability and Autonomy for Micro Air Vehicles  

NASA Technical Reports Server (NTRS)

Substantial progress has been made recently towards design building and test-flying remotely piloted Micro Air Vehicle's (MAVs). We seek to complement this progress in overcoming the aerodynamic obstacles to.flight at very small scales with a vision stability and autonomy system. The developed system based on a robust horizon detection algorithm which we discuss in greater detail in a companion paper. In this paper, we first motivate the use of computer vision for MAV autonomy arguing that given current sensor technology, vision may he the only practical approach to the problem. We then briefly review our statistical vision-based horizon detection algorithm, which has been demonstrated at 30Hz with over 99.9% correct horizon identification. Next we develop robust schemes for the detection of extreme MAV attitudes, where no horizon is visible, and for the detection of horizon estimation errors, due to external factors such as video transmission noise. Finally, we discuss our feed-back controller for self-stabilized flight, and report results on vision autonomous flights of duration exceeding ten minutes.

Ettinger, Scott M.; Nechyba, Michael C.; Ifju, Peter G.; Wazak, Martin

2002-01-01

252

Vibration Effects Examination of Cushions Used on Tractor Driving Seat  

NASA Astrophysics Data System (ADS)

Vibration effect of driver’s seat of agricultural tractor which works in land condition has been researched. In this research, three dif- ferent cushions on driver’s seat have been used. These are wool, sponge and cotton. Pad acceleration receiver is put on seat. Moreover, HVM100 tool has been used to record data. Data has been converted to graphs in BLAZE software. Statistical methods have been used in examining the graphs. In vibration isolation, ordering has been achieved as wool, cotton and sponge and without a cushion, respectively. Wool cushion has the best isolation. It is seen that data obtained from test results is appropri- ate according to ISO 2631 standards and scientific researches.

Marul, Musa; Karabulut, Abdurrahman

2012-12-01

253

Lightweight, fire-retardant, crashworthy aircraft seat cushioning  

NASA Technical Reports Server (NTRS)

A two page discussion of non-aerospace seating applications and the design of NASA's safety seat cushioning (SSC) is presented. The SSC was designed for both safety and comfort in order to replace polyurethane cushioning which is flammable and produces lethal fumes upon combustion. The SSC is composed of advanced fabric reinforced composites and is lightweight, fire-retardent, and crashworthy. The seat design consists of central elliptical tubular spring supports made of fire-resistant and fatigue-durable composites surrounded by a fire-blocking sheath. The cushioning is made crashworthy by incorporating energy-absorbing, viscoelastic layers between the nested, elliptical-hoop springs. The design is intended to provide comfortable seating that meets aircraft-loading requirements without using the conventional polyurethane materials. The designs of an aircraft seat and structural components of the SSC are also presented.

Haslim, Leonard A.; Mcdonough, Paul T.

1991-01-01

254

A model to assess the comfort of automotive seat cushions.  

PubMed

A large number of independent and interacting factors affect seating comfort such as seat shape, stability, lumbar support and seat height. Although many subjective comfort studies have been conducted, few of them considered seating comfort from its subassembly level. This paper analyzed the automotive seat cushion designed with geared four-bar linkage for the seat height adjustment. The operation torque and lift distance of this mechanism was investigated as 2 major comfort factors. Ten cushions with this kind of design in the market were compared and assessed. PMID:25189755

Jiaxing, Zhan; Fard, Mohammad; Jazar, Reza

2014-01-01

255

Development of a cushion to prevent ischial pressure sores.  

PubMed Central

A study was carried out jointly by nursing staff and technologists in an attempt to develop a cushion based on scientific principles and measurement that might prevent pressure sores. At each stage in the development clinical trials were carried out, and using the results of these together with the opinions of medical staff and patients who used the cushion the design was suitably modified. Over four years a seat was evolved that was simple to construct and fulfilled the clinical requirements for a wide range of patients while providing maximum relief of high-pressure points. The design was subsequently taken up commercially. Images Fig 3 PMID:509176

Bowker, P; Davidson, L M

1979-01-01

256

Internal air flow analysis of a bladeless micro aerial vehicle hemisphere body using computational fluid dynamic  

NASA Astrophysics Data System (ADS)

This paper explain the analysis of internal air flow velocity of a bladeless vertical takeoff and landing (VTOL) Micro Aerial Vehicle (MAV) hemisphere body. In mechanical design, before produce a prototype model, several analyses should be done to ensure the product's effectiveness and efficiency. There are two types of analysis method can be done in mechanical design; mathematical modeling and computational fluid dynamic. In this analysis, I used computational fluid dynamic (CFD) by using SolidWorks Flow Simulation software. The idea came through to overcome the problem of ordinary quadrotor UAV which has larger size due to using four rotors and the propellers are exposed to environment. The bladeless MAV body is designed to protect all electronic parts, which means it can be used in rainy condition. It also has been made to increase the thrust produced by the ducted propeller compare to exposed propeller. From the analysis result, the air flow velocity at the ducted area increased to twice the inlet air. This means that the duct contribute to the increasing of air velocity.

Othman, M. N. K.; Zuradzman, M. Razlan; Hazry, D.; Khairunizam, Wan; Shahriman, A. B.; Yaacob, S.; Ahmed, S. Faiz; Hussain, Abadalsalam T.

2014-12-01

257

Survey of Aerothermodynamics Facilities Useful for the Design of Hypersonic Vehicles Using Air-Breathing Propulsion  

NASA Technical Reports Server (NTRS)

The dream of producing an air-breathing, hydrogen fueled, hypervelocity aircraft has been before the aerospace community for decades. However, such a craft has not yet been realized, even in an experimental form. Despite the simplicity and beauty of the concept, many formidable problems must be overcome to make this dream a reality. This paper summarizes the aero/aerothermodynamic issues that must be addressed to make the dream a reality and discusses how aerothermodynamics facilities and their modem companion, real-gas computational fluid dynamics (CFD), can help solve the problems blocking the way to realizing the dream. The approach of the paper is first to outline the concept of an air-breathing hypersonic vehicle and then discuss the nose-to-tail aerothermodynamics issues and special aerodynamic problems that arise with such a craft. Then the utility of aerothermodynamic facilities and companion CFD analysis is illustrated by reviewing results from recent United States publications wherein these problems have been addressed. Papers selected for the discussion have k e n chosen such that the review will serve to survey important U.S. aero/aerothermodynamic real gas and conventional wind tunnel facilities that are useful in the study of hypersonic, hydrogen propelled hypervelocity vehicles.

Arnold, James O.; Deiwert, G. S.

1997-01-01

258

Air quality impacts of climate mitigation: UK policy and passenger vehicle choice.  

PubMed

In 2001-2002 the UK began taxing vehicles according to CO2 emission rates. Since then, there has been a significant increase in consumer choice of small cars and diesel engines. We estimate CO2 reductions and air quality impacts resulting from UK consumers switching from petrol to diesel cars from 2001 to 2020. Annual reductions of 0.4 megatons (Mt) of CO2 and 1 million barrels of oil are estimated from switching to diesels. However, diesels emit higher levels of particulate matter estimated to result in 90 deaths annually (range 20-300). We estimate 570, 460, and 0 additional deaths per Mt of CO2 abated, for Euro III, Euro IV, and post-Euro IV emission class vehicles, respectively. CO2 policies are suspected to have contributed substantially to diesel growth, but the magnitude of impact has yet to be quantified rigorously. To the extent that CO2 policies contribute to diesel growth, coordinating CO2 controls with tightening of emission standards would save lives. This research shows that climate policy, while reducing fuel use and CO2, does not always ensure ancillary health benefits. Lessons from the UK can help inform policies designed elsewhere which strive to balance near-term ambient air quality and health with long-term climate mitigation. PMID:17310696

Mazzi, Eric A; Dowlatabadi, Hadi

2007-01-15

259

Neighborhood-scale air quality impacts of emissions from motor vehicles and aircraft  

NASA Astrophysics Data System (ADS)

A mobile monitoring platform (MMP) was used to measure real-time air pollutant concentrations in different built environments of Boyle Heights (BH, a lower-income community enclosed by several freeways); Downtown Los Angeles (DTLA, adjacent to BH with taller buildings and surrounded by several freeways); and West Los Angeles (WLA, an affluent community traversed by two freeways) in summer afternoons of 2008 and 2011 (only for WLA). Significant inter-community and less significant but observable intra-community differences in traffic-related pollutant concentrations were observed both in the residential neighborhoods studied and on their arterial roadways between BH, DTLA, and WLA, particularly for ultrafine particles (UFP). HEV, defined as vehicles creating plumes with concentrations more than three standard deviations from the adjusted local baseline, were encountered during 6-13% of sampling time, during which they accounted for 17-55% of total UFP concentrations both on arterial roadways and in residential neighborhoods. If instead a single threshold value is used to define HEVs in all areas, HEV's were calculated to make larger contributions to UFP concentrations in BH than other communities by factors of 2-10 or more. Santa Monica Airport located in WLA appears to be a significant source for elevated UFP concentrations in nearby residential neighborhoods 80-400 m downwind. In the WLA area, we also showed, on a neighborhood scale, striking and immediate reductions in particulate pollution (?70% reductions in both UFP and, somewhat surprisingly, PM2.5), corresponding to dramatic decreases in traffic densities during an I-405 closure event (“Carmageddon”) compared to non-closure Saturday levels. Although pollution reduction due to decreased traffic is not unexpected, this dramatic improvement in particulate pollution provides clear evidence air quality can be improved through strategies such as heavy-duty-diesel vehicle retrofits, earlier retirement of HEV, and transition to electric vehicles and alternative fuels, with corresponding benefits for public health.

Choi, Wonsik; Hu, Shishan; He, Meilu; Kozawa, Kathleen; Mara, Steve; Winer, Arthur M.; Paulson, Suzanne E.

2013-12-01

260

Vehicle cabin cooling system for capturing and exhausting heated boundary layer air from inner surfaces of solar heated windows  

DOEpatents

The cabin cooling system includes a cooling duct positioned proximate and above upper edges of one or more windows of a vehicle to exhaust hot air as the air is heated by inner surfaces of the windows and forms thin boundary layers of heated air adjacent the heated windows. The cabin cooling system includes at least one fan to draw the hot air into the cooling duct at a flow rate that captures the hot air in the boundary layer without capturing a significant portion of the cooler cabin interior air and to discharge the hot air at a point outside the vehicle cabin, such as the vehicle trunk. In a preferred embodiment, the cooling duct has a cross-sectional area that gradually increases from a distal point to a proximal point to the fan inlet to develop a substantially uniform pressure drop along the length of the cooling duct. Correspondingly, this cross-sectional configuration develops a uniform suction pressure and uniform flow rate at the upper edge of the window to capture the hot air in the boundary layer adjacent each window.

Farrington, Robert B. (Golden, CO); Anderson, Ren (Broomfield, CO)

2001-01-01

261

The use of compressed natural gas (CNG) in motor vehicles and its effect on employment and air quality  

Microsoft Academic Search

This study measures industrial output, employment and air pollution effects through the use of CNG in motor vehicles by utilizing the Pollution-Related Multiregional Household-Interactive Variable Input-Output (PHVIO) model. The impact analyses are conducted with three consecutive year scenarios of different level of CNG conversion of motor fleet vehicles for the target year, 1991, 1992, and 1993. The use of CNG

Chung J. Liew; Chong K. Liew

1995-01-01

262

The potential impacts of electric vehicles on air quality in the urban areas of Barcelona and Madrid (Spain)  

NASA Astrophysics Data System (ADS)

This work analyses the potential air quality improvements resulting from three fleet electrification scenarios (?13, 26 and 40%) by replacing conventional vehicles with Electric Battery Vehicles (EBVs), Plug-in Hybrid Electric Vehicles (PHEVs) and Hybrid Electric Vehicles (HEVs). This study has been performed for the cities of Barcelona and Madrid (Spain), where road transport is the primary emission source. In these urban areas, several air quality problems are present, mainly related to NO2 and particulate matter. The WRF-ARW/HERMESv2/CMAQ model system has been applied at high spatial (1 × 1 km2) and temporal (1 h) resolution. The results show that fleet electrification offers a potential for emission abatement, especially related to NOx and CO. Regarding the more ambitious scenario (?40% fleet electrification), reductions of 11% and 17% of the total NOx emissions are observed in Barcelona and Madrid respectively. These emissions reductions involve air quality improvements in NO2 maximum hourly values up to 16%: reductions up to 30 and 35 ?g m-3 in Barcelona and Madrid, respectively. Furthermore, an additional scenario has been defined considering electric generation emissions associated with EBVs and PHEVs charging from a combined-cycle power plant. These charging emissions would produce slight NO2 increases in the downwind areas of <3 ?g m-3. Thus, fleet electrification would improve urban air quality even when considering emissions associated with charging electric vehicles. However, two further points should be considered. First, fleet electrification cannot be considered a unique solution, and other management strategies may be defined. This is especially important with respect to particulate matter emissions, which are not significantly reduced by fleet electrification (<5%) due to the high weight of non-exhaust emissions. Second, a significant introduction of electric vehicles (26-40%) involving all vehicle categories is required to improve urban air quality.

Soret, A.; Guevara, M.; Baldasano, J. M.

2014-12-01

263

DATE : NVLAP LAB CODE: NVLAP CARPET AND CARPET CUSHION  

E-print Network

-2 Reaction to Fire Tests for Floorings ­ Part 2: Determination of Flame Spread at a Heat Flux Level of 25 kDATE : NVLAP LAB CODE: NVLAP CARPET AND CARPET CUSHION TEST METHOD SELECTION LIST Instructions: Check each test method for which you are requesting accreditation. An asterisk (*) beside the NVLAP Test

264

76 FR 55859 - Federal Motor Vehicle Safety Standards No. 121; Air Brake Systems  

Federal Register 2010, 2011, 2012, 2013, 2014

...Federal Motor Vehicle Safety Standard...newly-manufactured vehicles equipped with...agency require a driver-controllable...increase in two-vehicle rear end crashes...the striking vehicle. However, this...mph, allowing drivers to disable the...altogether on heavy vehicles. The...

2011-09-09

265

Moss cushions facilitate water and nutrient supply for plant species on bare limestone pavements.  

PubMed

Dense moss cushions of different size are distributed across the bare limestone pavements on Øland, SE Sweden. Increasing cushion size is predicted to physically protect and improve performance and colonization by vascular plants. Therefore, we tested water balance, phosphorus supply, and species richness, and evaluated duration of plant activity during desiccation as a function of ground area, for a large collection of moss cushions. We found that lower evaporation and higher water storage contributed equally to extending the desiccation period with increasing cushion size. Evaporation rates declined by the -0.36 power of cushion diameter, and were not significantly different from -0.50 for the square root function previously predicted for the increasing thickness of the boundary layer, with greater linear dimensions for smooth flat objects at low wind velocities. Size dependence vanished under stagnant conditions. One moss species was added to the species pool for every nine-fold increase in cushion area. Vascular plants were absent from the smallest cushions, whereas one or two species, on average, appeared in 375- and 8,500-cm(2) cushions with water available for 6 and 10 days during desiccation. Phosphorus concentrations increased stepwise and four-fold from detritus to surface mosses and to vascular plants, and all three pools increased with cushion size. We conclude that cushion mosses and cushion size play a critical role in this resource-limited limestone environment by offering an oasis of improved water and nutrient supply to colonization and growth of plants. PMID:22481304

Sand-Jensen, Kaj; Hammer, Kathrine Jul

2012-10-01

266

Experimental Investigation of a Shrouded Rotor Micro Air Vehicle in Hover and in Edgewise Gusts  

NASA Astrophysics Data System (ADS)

Due to the hover capability of rotary wing Micro Air Vehicles (MAVs), it is of interest to improve their aerodynamic performance, and hence hover endurance (or payload capability). In this research, a shrouded rotor configuration is studied and implemented, that has the potential to offer two key operational benefits: enhanced system thrust for a given input power, and improved structural rigidity and crashworthiness of an MAV platform. The main challenges involved in realising such a system for a lightweight craft are: design of a lightweight and stiff shroud, and increased sensitivity to external flow disturbances that can affect flight stability. These key aspects are addressed and studied in order to assess the capability of the shrouded rotor as a platform of choice for MAV applications. A fully functional shrouded rotor vehicle (disk loading 60 N/ m2) was designed and constructed with key shroud design variables derived from previous studies on micro shrouded rotors. The vehicle weighed about 280 g (244 mm rotor diameter). The shrouded rotor had a 30% increase in power loading in hover compared to an unshrouded rotor. Due to the stiff, lightweight shroud construction, a net payload benefit of 20-30 g was achieved. The different components such as the rotor, stabilizer bar, yaw control vanes and the shroud were systematically studied for system efficiency and overall aerodynamic improvements. Analysis of the data showed that the chosen shroud dimensions was close to optimum for a design payload of 250 g. Risk reduction prototypes were built to sequentially arrive at the final configuration. In order to prevent periodic oscillations in ight, a hingeless rotor was incorporated in the shroud. The vehicle was successfully ight tested in hover with a proportional-integralderivative feedback controller. A flybarless rotor was incorporated for efficiency and control moment improvements. Time domain system identification of the attitude dynamics of the flybar and flybarless rotor vehicle was conducted about hover. Controllability metrics were extracted based on controllability gramian treatment for the flybar and flybarless rotor. In edgewise gusts, the shrouded rotor generated up to 3 times greater pitching moment and 80% greater drag than an equivalent unshrouded rotor. In order to improve gust tolerance and control moments, rotor design optimizations were made by varying solidity, collective, operating RPM and planform. A rectangular planform rotor at a collective of 18 deg was seen to offer the highest control authority. The shrouded rotor produced 100% higher control moments due to pressure asymmetry arising from cyclic control of the rotor. It was seen that the control margin of the shrouded rotor increased as the disk loading increased, which is however deleterious in terms of hover performance. This is an important trade-off that needs to be considered. The flight performance of the vehicle in terms of edgewise gust disturbance rejection was tested in a series of bench top and free ight tests. A standard table fan and an open jet wind tunnel setup was used for bench top setup. The shrouded rotor had an edgewise gust tolerance of about 3 m/s while the unshrouded rotor could tolerate edgewise gusts greater than 5 m/s. Free flight tests on the vehicle, using VICON for position feedback control, indicated the capability of the vehicle to recover from gust impulse inputs from a pedestal fan at low gust values (up to 3 m/s).

Hrishikeshavan, Vikram

267

Short communication: Genetic characterization of digital cushion thickness.  

PubMed

Dairy cow lameness is a serious animal welfare issue. It is also a significant cause of economic losses, reducing reproductive efficiency and milk production and increasing culling rates. The digital cushion is a complex structure composed mostly of adipose tissue located underneath the distal phalanx and has recently been phenotypically associated with incidence of claw horn disruption lesions (CHDL); namely, sole ulcers and white line disease. The objective of this study was to characterize digital cushion thickness genetically and to investigate its association with body condition score (BCS), locomotion score (LOCO), CHDL, and milk production. Data were collected from 1 large closely monitored commercial dairy farm located in upstate New York; 923 dairy cows were used. Before trimming, the following data were collected by a member of the research team: BCS, cow height measurement, and LOCO. Presence or not of CHDL (sole ulcer or white line disease, or both) was recorded at trimming. Immediately after the cows were hoof trimmed, they underwent digital sonographic B-mode examination for the measurement of digital cushion thickness. Factors such as parity number, stage of lactation, calving date, mature-equivalent 305-d milk yield (ME305MY), and pedigree information were obtained from the farm's dairy management software (DairyCOMP 305; Valley Agricultural Software, Tulare, CA). Univariate animal models were used to obtain variance component estimations for each studied trait (CHDL, BCS, digital cushion thickness average, LOCO, height, and ME305MY) and a 6-variate analysis was conducted to estimate the genetic, residual, and phenotypic correlations between the studied traits. The heritability estimate of DCTA was 0.33±0.09, whereas a statistically significant genetic correlation was estimated between DCTA and CHDL (-0.60±0.29). Of the other genetic correlations, significant estimates were derived for BCS with LOCO (-0.49±0.19) and ME305MY (-0.48±0.20). Digital cushion thickness is moderately heritable and genetically strongly correlated with CHDL. PMID:24239082

Oikonomou, G; Banos, G; Machado, V; Caixeta, L; Bicalho, R C

2014-01-01

268

Life cycle air emissions impacts and ownership costs of light-duty vehicles using natural gas as a primary energy source.  

PubMed

This paper aims to comprehensively distinguish among the merits of different vehicles using a common primary energy source. In this study, we consider compressed natural gas (CNG) use directly in conventional vehicles (CV) and hybrid electric vehicles (HEV), and natural gas-derived electricity (NG-e) use in plug-in battery electric vehicles (BEV). This study evaluates the incremental life cycle air emissions (climate change and human health) impacts and life cycle ownership costs of non-plug-in (CV and HEV) and plug-in light-duty vehicles. Replacing a gasoline CV with a CNG CV, or a CNG CV with a CNG HEV, can provide life cycle air emissions impact benefits without increasing ownership costs; however, the NG-e BEV will likely increase costs (90% confidence interval: $1000 to $31?000 incremental cost per vehicle lifetime). Furthermore, eliminating HEV tailpipe emissions via plug-in vehicles has an insignificant incremental benefit, due to high uncertainties, with emissions cost benefits between -$1000 and $2000. Vehicle criteria air contaminants are a relatively minor contributor to life cycle air emissions impacts because of strict vehicle emissions standards. Therefore, policies should focus on adoption of plug-in vehicles in nonattainment regions, because CNG vehicles are likely more cost-effective at providing overall life cycle air emissions impact benefits. PMID:25825338

Luk, Jason M; Saville, Bradley A; MacLean, Heather L

2015-04-21

269

21 CFR 890.3175 - Flotation cushion.  

Code of Federal Regulations, 2012 CFR

...with water, air, gel, mud, or any other substance allowing a flotation media, used on a seat to lessen the likelihood of skin ulcers. (b) Classification. Class I (general controls). The device is exempt from the premarket notification...

2012-04-01

270

Q-learning approach to automated unmanned air vehicle (UAV) demining  

NASA Astrophysics Data System (ADS)

This paper develops a Q-learning approach to Unmanned Air Vehicle (UAV) navigation, or path planning, for sensing applications in which an infrared (IR) sensor or camera is installed onboard the UAV for the purpose of detecting and classifying multiple, stationary ground targets. The problem can be considered as a geometric sensor-path planning problem, because the geometry and position of the sensor's field of view (FOV) determines what targets can be detected and classified at any given time. The advantage of this approach over existing path planning techniques is that the optimal guidance policy is learned via the Q-function, without explicit knowledge of the system models and environmental conditions. The approach is demonstrated through a demining application in which a UAV-based IR sensor is capable of determining the optimal altitude for properly detecting and classifying targets buried in a complex region of interest.

Ferrari, Silvia; Daugherty, Greyson

2010-04-01

271

NASA Innovation Fund 2010 Project Elastically Shaped Future Air Vehicle Concept  

NASA Technical Reports Server (NTRS)

This report describes a study conducted in 2010 under the NASA Innovation Fund Award to develop innovative future air vehicle concepts. Aerodynamic optimization was performed to produce three different aircraft configuration concepts for low drag, namely drooped wing, inflected wing, and squashed fuselage. A novel wing shaping control concept is introduced. This concept describes a new capability of actively controlling wing shape in-flight to minimize drag. In addition, a novel flight control effector concept is developed to enable wing shaping control. This concept is called a variable camber continuous trailing edge flap that can reduce drag by as much as 50% over a conventional flap. In totality, the potential benefits of fuel savings offered by these concepts can be significant.

Nguyen, Nhan

2010-01-01

272

Estimation of road vehicle exhaust emissions from 1992 to 2010 and comparison with air quality measurements in Genoa, Italy  

NASA Astrophysics Data System (ADS)

An investigation into road transport exhaust emissions in the Genoa urban area was performed by comparing the quantities of carbon monoxide (CO), nitrogen oxides (NO x), nitrogen dioxide (NO 2) and particulate matter (PM) emitted by different vehicle categories with air quality measurements referred to the same pollutants. Exhaust emissions were evaluated by applying the PROGRESS (computer PROGramme for Road vehicle EmiSSions evaluation) code, developed by the Internal Combustion Engines Group of the University of Genoa, to eight different years (from 1992 to 2010), considering spark ignition and Diesel passenger cars and light duty vehicles, heavy duty vehicles and buses, motorcycles and mopeds. Changes in terms of vehicles number, mileage and total emissions are presented together with relative distributions among the various vehicle categories. By comparing 1992 and 2010 data, calculated trends show a 7% increase in the number of vehicles, with total mileage growing at a faster rate (approx. 22%); total emissions decrease considerably, by approximately 50% for NO x and PM, 70% for HC and 80% for CO, due to improvements in engines and fuels forced by the stricter European legislation and the fleet renewal, while primary NO 2 emission will be very close to 1992 level, after a decrease of about 18% in 2000. Air quality was analysed by selecting traffic and background measuring stations from the monitoring network managed by the Environmental Department of the Province of Genoa: average annual concentrations of considered pollutants from 1994 to 2007 were calculated in order to obtain the relative historical trends and compare them with European public health limits and with road vehicle emissions. Though an important reduction in pollutant concentrations has been achieved as a consequence of cleaner vehicles, some difficulties in complying with present and/or future NO 2 and PM 10 limits are also apparent, thus requiring suitable measures to be taken by the local authorities.

Zamboni, Giorgio; Capobianco, Massimo; Daminelli, Enrico

273

Uncertainty analysis and robust trajectory linearization control of a flexible air-breathing hypersonic vehicle  

NASA Astrophysics Data System (ADS)

Flexible air-breathing hypersonic vehicles feature significant uncertainties which pose huge challenges to robust controller designs. In this paper, four major categories of uncertainties are analyzed, that is, uncertainties associated with flexible effects, aerodynamic parameter variations, external environmental disturbances, and control-oriented modeling errors. A uniform nonlinear uncertainty model is explored for the first three uncertainties which lumps all uncertainties together and consequently is beneficial for controller synthesis. The fourth uncertainty is additionally considered in stability analysis. Based on these analyses, the starting point of the control design is to decompose the vehicle dynamics into five functional subsystems. Then a robust trajectory linearization control (TLC) scheme consisting of five robust subsystem controllers is proposed. In each subsystem controller, TLC is combined with the extended state observer (ESO) technique for uncertainty compensation. The stability of the overall closed-loop system with the four aforementioned uncertainties and additional singular perturbations is analyzed. Particularly, the stability of nonlinear ESO is also discussed from a Liénard system perspective. At last, simulations demonstrate the great control performance and the uncertainty rejection ability of the robust scheme.

Pu, Zhiqiang; Tan, Xiangmin; Fan, Guoliang; Yi, Jianqiang

2014-08-01

274

Aerodynamics of a bio-inspired flexible flapping-wing micro air vehicle.  

PubMed

MAVs (micro air vehicles) with a maximal dimension of 15 cm and nominal flight speeds of around 10 m s?¹, operate in a Reynolds number regime of 10? or lower, in which most natural flyers including insects, bats and birds fly. Furthermore, due to their light weight and low flight speed, the MAVs' flight characteristics are substantially affected by environmental factors such as wind gust. Like natural flyers, the wing structures of MAVs are often flexible and tend to deform during flight. Consequently, the aero/fluid and structural dynamics of these flyers are closely linked to each other, making the entire flight vehicle difficult to analyze. We have recently developed a hummingbird-inspired, flapping flexible wing MAV with a weight of 2.4-3.0 g and a wingspan of 10-12 cm. In this study, we carry out an integrated study of the flexible wing aerodynamics of this flapping MAV by combining an in-house computational fluid dynamic (CFD) method and wind tunnel experiments. A CFD model that has a realistic wing planform and can mimic realistic flexible wing kinematics is established, which provides a quantitative prediction of unsteady aerodynamics of the four-winged MAV in terms of vortex and wake structures and their relationship with aerodynamic force generation. Wind tunnel experiments further confirm the effectiveness of the clap and fling mechanism employed in this bio-inspired MAV as well as the importance of the wing flexibility in designing small flapping-wing MAVs. PMID:22126793

Nakata, T; Liu, H; Tanaka, Y; Nishihashi, N; Wang, X; Sato, A

2011-12-01

275

The development of an experimental facility and investigation of rapidly maneuvering Micro-Air-Vehicle wings  

NASA Astrophysics Data System (ADS)

Vertical Takeoff-and-Landing (VTOL) Micro Air Vehicles (MAVs) provide a versatile operational platform which combines the capabilities of fixed wing and rotary wing MAVs. In order to improve performance of these vehicles, a better understanding of the rapid transition between horizontal and vertical flight is required. This study examines the flow structures around the Mini-Vertigo VTOL MAV using flow visualization techniques. This will gives an understanding of the flow structures which dominate the flight dynamics of rapid pitching maneuvers. This study consists of three objectives: develop an experimental facility, use flow visualization to investigate the flow around the experimental subject during pitching, and analyze the results. The flow around the Mini-Vertigo VTOL MAV is dominated by the slipstream from its propellers. The slipstream delays LE separation and causes drastic deflection in the flow. While the frequency of the vortices shed from the LE and TE varies with flow speed, the non-dimensional frequency does not. It does, however, vary slightly with the pitching rate. These results are applicable across a wide range of flight conditions. The results correlate to previous research done to examine the aerodynamic forces on the MAV.

Wilson, Lee Alexander

276

A parallel expert system for the control of a robotic air vehicle  

NASA Technical Reports Server (NTRS)

Expert systems can be used to govern the intelligent control of vehicles, for example the Robotic Air Vehicle (RAV). Due to the nature of the RAV system the associated expert system needs to perform in a demanding real-time environment. The use of a parallel processing capability to support the associated expert system's computational requirement is critical in this application. Thus, algorithms for parallel real-time expert systems must be designed, analyzed, and synthesized. The design process incorporates a consideration of the rule-set/face-set size along with representation issues. These issues are looked at in reference to information movement and various inference mechanisms. Also examined is the process involved with transporting the RAV expert system functions from the TI Explorer, where they are implemented in the Automated Reasoning Tool (ART), to the iPSC Hypercube, where the system is synthesized using Concurrent Common LISP (CCLISP). The transformation process for the ART to CCLISP conversion is described. The performance characteristics of the parallel implementation of these expert systems on the iPSC Hypercube are compared to the TI Explorer implementation.

Shakley, Donald; Lamont, Gary B.

1988-01-01

277

A refuelable zinc/air battery for fleet electric vehicle propulsion  

NASA Astrophysics Data System (ADS)

We report the development and on-vehicle testing of an engineering prototype zinc/air battery. The battery is refueled by periodic exchange of spent electrolyte for zinc particles entrained in fresh electrolyte. The technology is intended to provide a capability for nearly continuous vehicle operation, using the fleet's home base for 10 minute refuelings and zinc recycling instead of commercial infrastructure. In the battery, the zinc fuel particles are stored in hoppers, from which they are gravity fed into individual cells and completely consumed during discharge. A six-celled (7V) engineering prototype battery was combined with a 6 V lead/acid battery to form a parallel hybrid unit, which was tested in series with the 216 V battery of an electric shuttle bus over a 75 mile circuit. The battery has an energy density of 140 Wh/kg and a mass density of 1.5 kg/L. Cost, energy efficiency, and alternative hybrid configurations are discussed.

Cooper, John F.; Fleming, Dennis; Hargrove, Douglas; Koopman, Ronald; Peterman, Keith

1995-04-01

278

Contribution of vehicle emissions to ambient carbonaceous particulate matter: A review and synthesis of the available data in the South Coast Air Basin. Final report  

SciTech Connect

Table of Contents: Executive Summary; Introduction; Ambient Carbonaceous Particulate Matter in the South Coast Air Basin; Measurements of Emissions from In-Use Motor Vehicles in the South Coast Air Basin; Integration of Emissions Measurements into Comprehensive Emissions Inventories; Relating Emissions fom Motor Vehicles to Particulate Air Quality; Synthesis: The Combined Effect of All Vehicle-Related Source Contributions Acting Together; Trends in More Recent Years; Opportunities for Further Research; References; Appendix A: Detailed Mass Emissions Rates for Organic Compounds from Motor Vehicle Exhaust; and Appendix B: Organic Compounds Emitted from Tire Dust, Paved Road Dust, and Brake Lining Wear Dust.

Cass, G.R.

1997-02-01

279

78 FR 20881 - Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards...  

Federal Register 2010, 2011, 2012, 2013, 2014

...regulations to establish more stringent vehicle emissions standards and reduce the sulfur content of gasoline beginning in 2017, as part of a systems...proposed gasoline sulfur standard would make emission control systems more effective for both...

2013-04-08

280

Networking Multiple Autonomous Air and Ocean Vehicles for Oceanographic Research and Monitoring  

NASA Astrophysics Data System (ADS)

Autonomous underwater and surface vessels (AUVs and ASVs) are coming into wider use as components of oceanographic research, including ocean observing systems. Unmanned airborne vehicles (UAVs) are now available at modest cost, allowing multiple UAVs to be deployed with multiple AUVs and ASVs. For optimal use good communication and coordination among vehicles is essential. We report on the use of multiple AUVs networked in communication with multiple UAVs. The UAVs are augmented by inferential reasoning software developed at MBARI that allows UAVs to recognize oceanographic fronts and change their navigation and control. This in turn allows UAVs to automatically to map frontal features, as well as to direct AUVs and ASVs to proceed to such features and conduct sampling via onboard sensors to provide validation for airborne mapping. ASVs can also act as data nodes for communication between UAVs and AUVs, as well as collecting data from onboard sensors, while AUVs can sample the water column vertically. This allows more accurate estimation of phytoplankton biomass and productivity, and can be used in conjunction with UAV sampling to determine air-sea flux of gases (e.g. CO2, CH4, DMS) affecting carbon budgets and atmospheric composition. In particular we describe tests in July 2013 conducted off Sesimbra, Portugal in conjunction with the Portuguese Navy by the University of Porto and MBARI with the goal of tracking large fish in the upper water column with coordinated air/surface/underwater measurements. A thermal gradient was observed in the infrared by a low flying UAV, which was used to dispatch an AUV to obtain ground truth to demonstrate the event-response capabilities using such autonomous platforms. Additional field studies in the future will facilitate integration of multiple unmanned systems into research vessel operations. The strength of hardware and software tools described in this study is to permit fundamental oceanographic measurements of both ocean and atmosphere over temporal and spatial scales that have previously been problematic. The methods demonstrated are particularly suited to the study of oceanographic fronts and for tracking and mapping oil spills or plankton blooms. With the networked coordination of multiple autonomous systems, individual components may be changed out while ocean observations continue, allowing coarse to fine spatial studies of hydrographic features over temporal dimensions that would otherwise be difficult, including diurnal and tidal periods. Constraints on these methods currently involve coordination of data archiving systems into shipboard operating systems, familiarization of oceanographers with these methods, and existing nearshore airspace use constraints on UAVs. An important outcome of these efforts is to understand the methodology for using multiple heterogeneous autonomous vehicles for targeted science exploration.

McGillivary, P. A.; Borges de Sousa, J.; Rajan, K.

2013-12-01

281

Autonomous Hovering of a Fixed-Wing Micro Air Vehicle William E. Green and Paul Y. Oh  

E-print Network

Autonomous Hovering of a Fixed-Wing Micro Air Vehicle William E. Green and Paul Y. Oh Drexel with hovering capabilities. An in- ertial measurement sensor and an onboard processing and control unit, used to achieve autonomous hover- ing, are also described. This is, to the best of our knowledge, the first

Oh, Paul

282

Aerodynamics of low aspect ratio wings at low Reynolds numbers with applications to micro air vehicle design  

Microsoft Academic Search

The recent interest in the development of small UAVs and micro air vehicles has revealed a need for a more thorough understanding of the aerodynamics of small airplanes flying at low speeds. In response to this need, the present work presents a study of the lift, drag, and pitching moment characteristics of wings of low aspect ratio operating at low

Gabriel Eduardo Torres

2002-01-01

283

Experimental investigation of some aspects of insect-like flapping flight aerodynamics for application to micro air vehicles  

Microsoft Academic Search

Insect-like flapping flight offers a power-efficient and highly manoeuvrable basis for micro air vehicles for indoor applications. Some aspects of the aerodynamics associated with the sweeping phase of insect wing kinematics are examined by making particle image velocimetry measurements on a rotating wing immersed in a tank of seeded water. The work is motivated by the paucity of data with

Salman A. Ansari; Nathan Phillips; Graham Stabler; Peter C. Wilkins; Rafal Zbikowski; Kevin Knowles

2010-01-01

284

Highly efficient brushless motor design for an air-conditioner of the next generation 42 V vehicle  

Microsoft Academic Search

In the past few years, worldwide awareness of environmental problems has grown dramatically. The idling stop and 42 V battery system has attracted large attention for next generation vehicle. In order to adapt to idling stop, air-conditioning compressors are required to be changed to electric-motor driven from gasoline engine driven. This paper discusses the optimum design of a high speed

Hiroshi Murakami; Hisakazu Kataoka; Yukio Honda; Shigeo Morimoto; Yoji Takeda

2001-01-01

285

Heavy Metal Contamination of Soil, Plant and Air of Scrapyard of Discarded Vehicles at Zarqa City, Jordan  

Microsoft Academic Search

Ninety soil samples, forty plant samples (Anabasis articulata), and twenty air samples were collected from the scrap yard of discarded vehicles near Zarqa city, Jordan. These samples were analyzed for heavy metals: Cd, Pb, Zn, Cu, Mn, Al, and Fe. Longitudinal and vertical profiles of soil samples were studied. Generally, the levels of all heavy metals studied in the scrap

Qasem M. Jaradat; Adnan Masadeh; Mohammed A. Zaitoun; Baheyah M. Maitah

2005-01-01

286

Measurement of Air Traffic Control Situational Awareness Enhancement Through Radar Support Toward Operating Envelope Expansion of an Unmanned Aerial Vehicle  

Microsoft Academic Search

Current airspace restrictions in Kabul limit the potential capability of the tactical unmanned air vehicle (TUAV) within the area of operations of the Kabul multinational brigade. An experiment was conducted using the OneSAF Testbed Baseline and a range of virtual simulations to examine the impact of five different radar options and three different information displays on the level of airspace

James S. Denford; John A. Steele; Roger L. Roy; Eugenia Kalantzis

2004-01-01

287

Australian Air Breathing Propulsion Research for Hypersonic, Beamed Energy-Propelled Vehicles  

NASA Astrophysics Data System (ADS)

A three year laser-propelled vehicle analysis and design investigation has been begun in June, 2009 by Faculty and graduate students at the University of Adelaide under a Grant/Cooperative Agreement Award to the University of Adelaide by the Asian Office of Aerospace Research and Development (AOARD). The major objectives of thsis investigation are: (a) development of hypersonic, air breathing "lightcraft" with innovative air inlets that enable acceptable airflow capture and combustion, and acceptable cowl-lip heating rates during hot, high-speed, high angle-of-attack hypersonic flight; (b) yest of the most promising lightcraft and inlet design in the high power laser beam that is part of the shock tunnel facility at CTO Instituto in Brazil; and (c) plan a series of laser guided and propelled flights that achieve supersonic or higher speed at the Woomera Test Facility (WTF) in South Australia—using the existing WTF launching and tracking facilities and sponsor-provided laser pointing and tracking and illumination systems.

Froning, David

2010-05-01

288

Ground moving target geo-location from monocular camera mounted on a micro air vehicle  

NASA Astrophysics Data System (ADS)

The usual approaches to unmanned air vehicle(UAV)-to-ground target geo-location impose some severe constraints to the system, such as stationary objects, accurate geo-reference terrain database, or ground plane assumption. Micro air vehicle(MAV) works with characteristics including low altitude flight, limited payload and onboard sensors' low accuracy. According to these characteristics, a method is developed to determine the location of ground moving target which imaged from the air using monocular camera equipped on MAV. This method eliminates the requirements for terrain database (elevation maps) and altimeters that can provide MAV's and target's altitude. Instead, the proposed method only requires MAV flight status provided by its inherent onboard navigation system which includes inertial measurement unit(IMU) and global position system(GPS). The key is to get accurate information on the altitude of the ground moving target. First, Optical flow method extracts background static feature points. Setting a local region around the target in the current image, The features which are on the same plane with the target in this region are extracted, and are retained as aided features. Then, inverse-velocity method calculates the location of these points by integrated with aircraft status. The altitude of object, which is calculated by using position information of these aided features, combining with aircraft status and image coordinates, geo-locate the target. Meanwhile, a framework with Bayesian estimator is employed to eliminate noise caused by camera, IMU and GPS. Firstly, an extended Kalman filter(EKF) provides a simultaneous localization and mapping solution for the estimation of aircraft states and aided features location which defines the moving target local environment. Secondly, an unscented transformation(UT) method determines the estimated mean and covariance of target location from aircraft states and aided features location, and then exports them for the moving target Kalman filter(KF). Experimental results show that our method can instantaneously geo-locate the moving target by operator's single click and can reach 15 meters accuracy for an MAV flying at 200 meters above the ground.

Guo, Li; Ang, Haisong; Zheng, Xiangming

2011-08-01

289

Impact of underestimating the effects of cold temperature on motor vehicle start emissions of air toxics in the United States.  

PubMed

Analyses of U.S. Environmental Protection Agency (EPA) certification data, California Air Resources Board surveillance testing data, and EPA research testing data indicated that EPA's MOBILE6.2 emission factor model substantially underestimates emissions of gaseous air toxics occurring during vehicle starts at cold temperatures for light-duty vehicles and trucks meeting EPA Tier 1 and later standards. An unofficial version of the MOBILE6.2 model was created to account for these underestimates. When this unofficial version of the model was used to project emissions into the future, emissions increased by almost 100% by calendar year 2030, and estimated modeled ambient air toxics concentrations increased by 6-84%, depending on the pollutant. To address these elevated emissions, EPA recently finalized standards requiring reductions of emissions when engines start at cold temperatures. PMID:18200932

Cook, Richard; Touma, Jawad S; Fernandez, Antonio; Brzezinski, David; Bailey, Chad; Scarbro, Carl; Thurman, James; Strum, Madeleine; Ensley, Darrell; Baldauf, Richard

2007-12-01

290

Integration of Advanced Concepts and Vehicles Into the Next Generation Air Transportation System. Volume 1; Introduction, Key Messages, and Vehicle Attributes  

NASA Technical Reports Server (NTRS)

Raytheon, in partnership with NASA, is leading the way in ensuring that the future air transportation continues to be a key driver of economic growth and stability and that this system provides an environmentally friendly, safe, and effective means of moving people and goods. A Raytheon-led team of industry and academic experts, under NASA contract NNA08BA47C, looked at the potential issues and impact of introducing four new classes of advanced aircraft into the next generation air transportation system -- known as NextGen. The study will help determine where NASA should further invest in research to support the safe introduction of these new air vehicles. Small uncrewed or unmanned aerial systems (SUAS), super heavy transports (SHT) including hybrid wing body versions (HWB), very light jets (VLJ), and supersonic business jets (SSBJ) are the four classes of aircraft that we studied. Understanding each vehicle's business purpose and strategy is critical to assessing the feasibility of new aircraft operations and their impact on NextGen's architecture. The Raytheon team used scenarios created by aviation experts that depict vehicles in year 2025 operations along with scripts or use cases to understand the issues presented by these new types of vehicles. The information was then mapped into the Joint Planning and Development Office's (JPDO s) Enterprise Architecture to show how the vehicles will fit into NextGen's Concept of Operations. The team also identified significant changes to the JPDO's Integrated Work Plan (IWP) to optimize the NextGen vision for these vehicles. Using a proven enterprise architecture approach and the JPDO s Joint Planning Environment (JPE) web site helped make the leap from architecture to planning efficient, manageable and achievable. Very Light Jets flying into busy hub airports -- Supersonic Business Jets needing to climb and descend rapidly to achieve the necessary altitude Super-heavy cargo planes requiring the shortest common flight path -- are just a few of the potential new operations in the future National Airspace System. To assess the impact of these new scenarios on overall national airspace operations, the Raytheon team used the capabilities of a suite of tools such as NASA's Airspace Concepts Evaluation System (ACES), the Flight Optimization System (FLOPS), FAA's Aviation Environmental Design Tool (AEDT), Intelligent Automations Kinematic Trajectory Generator (KTG) and the Aviation Safety Risk Model (ASRM). Detailed metroplex modeling, surface delay models for super heavy transports, prioritized routing and corridors for supersonics business jets, and VLJ demand models are some of the models developed by the Raytheon team to study the effect of operating these new vehicles in the future NAS. Using this suite of models, several trade studies were conducted to evaluate these effects in terms of delays, equity in access, safety, and the environment. Looking at the impact of each vehicle, a number of critical issues were identified. The Raytheon team concluded that strict compliance to NextGen's 4-dimensional trajectory (4DT) management will be required to accommodate these vehicles unique operations and increased number of flights in the future air space system. The next section provides a discussion of this and the other key findings from our study.

Zellweger, Andres; Resnick, Herbert; Stevens, Edward; Arkind, Kenneth; Cotton William B.

2010-01-01

291

Design of composite plastic foams for improved cushioning  

E-print Network

of the trapped gas in the closed cell. Although the model eventually encompassed the foam density effect, viscoelastic and open-cell behavior were not addressed. A filament buckling model was proposed by Shuttleworth, Shestopal and Goss [11] in 1985...- teristics of plastic foams under impact conditions. Simi- larity parameters were proposed that allow the use of one cushioning diagram in lieu of the traditional numerous curves. In 1988, Burgess [13] concluded that behavior of closed-cell foams under...

Eskew, James Oliver

1989-01-01

292

Optimization of aircraft seat cushion fire blocking layers  

NASA Technical Reports Server (NTRS)

This report describes work completed by the National Aeronautics and Space Administration - for the Federal Aviation Administration Technical Center. The purpose of this work was to examine the potential of fire blocking mechanisms for aircraft seat cushions in order to provide an optimized seat configuration with adequate fire protection and minimum weight. Aluminized thermally stable fabrics were found to provide adequate fire protection when used in conjunction with urethane foams, while maintaining minimum weight and cost penalty.

Kourtides, D. A.; Parker, J. A.; Ling, A. C.; Hovatter, W. R.

1983-01-01

293

Fully Self-Contained Vision-Aided Navigation and Landing of a Micro Air Vehicle Independent from External Sensor Inputs  

NASA Technical Reports Server (NTRS)

Direct-lift micro air vehicles have important applications in reconnaissance. In order to conduct persistent surveillance in urban environments, it is essential that these systems can perform autonomous landing maneuvers on elevated surfaces that provide high vantage points without the help of any external sensor and with a fully contained on-board software solution. In this paper, we present a micro air vehicle that uses vision feedback from a single down looking camera to navigate autonomously and detect an elevated landing platform as a surrogate for a roof top. Our method requires no special preparation (labels or markers) of the landing location. Rather, leveraging the planar character of urban structure, the landing platform detection system uses a planar homography decomposition to detect landing targets and produce approach waypoints for autonomous landing. The vehicle control algorithm uses a Kalman filter based approach for pose estimation to fuse visual SLAM (PTAM) position estimates with IMU data to correct for high latency SLAM inputs and to increase the position estimate update rate in order to improve control stability. Scale recovery is achieved using inputs from a sonar altimeter. In experimental runs, we demonstrate a real-time implementation running on-board a micro aerial vehicle that is fully self-contained and independent from any external sensor information. With this method, the vehicle is able to search autonomously for a landing location and perform precision landing maneuvers on the detected targets.

Brockers, Roland; Susca, Sara; Zhu, David; Matthies, Larry

2012-01-01

294

Fully self-contained vision-aided navigation and landing of a micro air vehicle independent from external sensor inputs  

NASA Astrophysics Data System (ADS)

Direct-lift micro air vehicles have important applications in reconnaissance. In order to conduct persistent surveillance in urban environments, it is essential that these systems can perform autonomous landing maneuvers on elevated surfaces that provide high vantage points without the help of any external sensor and with a fully contained on-board software solution. In this paper, we present a micro air vehicle that uses vision feedback from a single down looking camera to navigate autonomously and detect an elevated landing platform as a surrogate for a roof top. Our method requires no special preparation (labels or markers) of the landing location. Rather, leveraging the planar character of urban structure, the landing platform detection system uses a planar homography decomposition to detect landing targets and produce approach waypoints for autonomous landing. The vehicle control algorithm uses a Kalman filter based approach for pose estimation to fuse visual SLAM (PTAM) position estimates with IMU data to correct for high latency SLAM inputs and to increase the position estimate update rate in order to improve control stability. Scale recovery is achieved using inputs from a sonar altimeter. In experimental runs, we demonstrate a real-time implementation running on-board a micro aerial vehicle that is fully self-contained and independent from any external sensor information. With this method, the vehicle is able to search autonomously for a landing location and perform precision landing maneuvers on the detected targets.

Brockers, Roland; Susca, Sara; Zhu, David; Matthies, Larry

2012-06-01

295

Autonomous landing and ingress of micro-air-vehicles in urban environments based on monocular vision  

NASA Astrophysics Data System (ADS)

Unmanned micro air vehicles (MAVs) will play an important role in future reconnaissance and search and rescue applications. In order to conduct persistent surveillance and to conserve energy, MAVs need the ability to land, and they need the ability to enter (ingress) buildings and other structures to conduct reconnaissance. To be safe and practical under a wide range of environmental conditions, landing and ingress maneuvers must be autonomous, using real-time, onboard sensor feedback. To address these key behaviors, we present a novel method for vision-based autonomous MAV landing and ingress using a single camera for two urban scenarios: landing on an elevated surface, representative of a rooftop, and ingress through a rectangular opening, representative of a door or window. Real-world scenarios will not include special navigation markers, so we rely on tracking arbitrary scene features; however, we do currently exploit planarity of the scene. Our vision system uses a planar homography decomposition to detect navigation targets and to produce approach waypoints as inputs to the vehicle control algorithm. Scene perception, planning, and control run onboard in real-time; at present we obtain aircraft position knowledge from an external motion capture system, but we expect to replace this in the near future with a fully self-contained, onboard, vision-aided state estimation algorithm. We demonstrate autonomous vision-based landing and ingress target detection with two different quadrotor MAV platforms. To our knowledge, this is the first demonstration of onboard, vision-based autonomous landing and ingress algorithms that do not use special purpose scene markers to identify the destination.

Brockers, Roland; Bouffard, Patrick; Ma, Jeremy; Matthies, Larry; Tomlin, Claire

2011-06-01

296

Autonomous Landing and Ingress of Micro-Air-Vehicles in Urban Environments Based on Monocular Vision  

NASA Technical Reports Server (NTRS)

Unmanned micro air vehicles (MAVs) will play an important role in future reconnaissance and search and rescue applications. In order to conduct persistent surveillance and to conserve energy, MAVs need the ability to land, and they need the ability to enter (ingress) buildings and other structures to conduct reconnaissance. To be safe and practical under a wide range of environmental conditions, landing and ingress maneuvers must be autonomous, using real-time, onboard sensor feedback. To address these key behaviors, we present a novel method for vision-based autonomous MAV landing and ingress using a single camera for two urban scenarios: landing on an elevated surface, representative of a rooftop, and ingress through a rectangular opening, representative of a door or window. Real-world scenarios will not include special navigation markers, so we rely on tracking arbitrary scene features; however, we do currently exploit planarity of the scene. Our vision system uses a planar homography decomposition to detect navigation targets and to produce approach waypoints as inputs to the vehicle control algorithm. Scene perception, planning, and control run onboard in real-time; at present we obtain aircraft position knowledge from an external motion capture system, but we expect to replace this in the near future with a fully self-contained, onboard, vision-aided state estimation algorithm. We demonstrate autonomous vision-based landing and ingress target detection with two different quadrotor MAV platforms. To our knowledge, this is the first demonstration of onboard, vision-based autonomous landing and ingress algorithms that do not use special purpose scene markers to identify the destination.

Brockers, Roland; Bouffard, Patrick; Ma, Jeremy; Matthies, Larry; Tomlin, Claire

2011-01-01

297

Micro-electro-mechanical flapping wing technology for micro air vehicles  

NASA Astrophysics Data System (ADS)

Army combat operations have placed a high premium on reconnaissance missions for Unmanned Aerial Vehicles (UAVs) and Micro Air Vehicles (MAVs) (less than 15 cm in dimension and less than 20 g in mass). One approach for accomplishing this mission is to develop a biologically inspired flapping wing insect that can maneuver into confined areas and possess hovering capabilities. Analysis of insect flight indicates that in addition to the bending excitation (flapping), simultaneous excitation of the twisting degree-of-freedom (pitching) is required to manipulate the control surface adequately. Traditionally, bimorph piezoelectric PZT (Pb(Zr0.55Ti0.45)O3) actuators have been used in many applications to excite the bending degree-of-freedom. In laminated or layered structures, bend-twist coupling is governed by the existence of at least one anisotropic layer not aligned with the primary plate axes. By adding a layer of off-axis PZT segments to a PZT bimorph actuator, thereby producing a layered structure to be referred to as a functionally- modified bimorph, bend-twist coupling may be introduced to the flexural response of the layered PZT. Furthermore, by selectively charging off-axis layers in specific combinations with the bimorph, the response of the functionally-modified bimorph may be tailored yielding a biaxial actuator to actively control the flapping wing response. The present study presents an experimental investigation of both traditional bimorph and functionally-modified PZT bimorph designs intended for active bend-twist actuation of cm-scale flapping wing devices.

Hall, Asha J.; Riddick, Jaret C.

2012-04-01

298

64 FR 26004 - Control of Air Pollution From New Motor Vehicles: Proposed Tier 2 Motor Vehicle Emissions...  

Federal Register 2010, 2011, 2012, 2013, 2014

...real reductions in sulfur. The size of the potential credit pool could...implementing such a program. The size of the pool potentially available...also developed for a fleet the size of the year 2010 fleet. For this...vehicle is sold, while the fuel related costs and the...

1999-05-13

299

Attitude estimation and maneuvering for autonomous obstacle avoidance by miniature air vehicles  

NASA Astrophysics Data System (ADS)

Utilizing the Euler-Rodrigues symmetric parameters (attitude quaternion) to describe vehicle orientation, we develop a multiplicative, nonlinear (extended) variation of the Kalman filter (MEKF) to fuse data from low-cost sensors. The sensor suite is comprised of gyroscopes, accelerometers, and a GPS receiver. In contrast to the common approach of using the complete vehicle attitude as the quantities to be estimated, our filter states consist of the three components of an attitude error vector. In parallel with the time update of the attitude error estimate, we utilize the gyroscope measurements for the time propagation of the attitude quaternion. The accelerometer and the GPS sensors are used independently for the measurement update portion of the Kalman filter. For both sensors, a vector arithmetic approach is used to determine the attitude error vector. Following each measurement update, a multiplicative reset operation moves the attitude error information from the filter state into the attitude estimate. This reset operation utilizes quaternion algebra to implicitly maintain the unity-norm constraint. We demonstrate the effectiveness of our attitude estimation algorithm through flight simulations and flight tests of aggressive maneuvers such as loops and small-radius circles. We implement an approach to acrobatic maneuvering for miniature air vehicles (MAVs) using time-parameterized attitude trajectory generation and an associated attitude tracking control law. We designed two methodologies, polynomial and trigonometric, for creating functions that specify pitch and roll angles as a function of time. For both approaches, the functions are constrained by the maneuver boundary conditions of aircraft position and velocity. We construct a trajectory tracking feedback control law to regulate aircraft orientation throughout the maneuvers. The trajectory generation algorithm was used to construct several maneuvers and trajectory tracking control law successfully executed the maneuvers in the flight simulator. In addition to the simulation results, MAV flight tests verified the performance of the maneuver generation and control. To achieve obstacle avoidance maneuvering, the time parameterized trajectories were converted to spatially parameterized paths, which allowed for inertial reference frame position error to be included in the control law feedback loop. We develop a novel method to achieve the spatial parameterization using a prediction and correction approach. Additionally, the first derivative of position of the desired path is modified using a corrective parameter scheme prior to being used in the control. Using the path position error and the corrected derivative, we utilize a unit-norm quaternion framework to implement a proportional-derivative (PD) control law. This control law was demonstrated in simulation and hardware on maneuvers designed specifically to avoid obstacles, namely the Immelmann and the Close-Q, as well as a basic loop.

Hall, James K.

300

Cell autonomous requirement of endocardial Smad4 during atrioventricular cushion development in mouse embryos.  

PubMed

Atrioventricular (AV) cushions are the precursors of AV septum and valves. In this study, we examined roles of Smad4 during AV cushion development using a conditional gene inactivation approach. We found that endothelial/endocardial inactivation of Smad4 led to the hypocellular AV cushion defect and that both reduced cell proliferation and increased apoptosis contributed to the defect. Expression of multiple genes critical for cushion development was down-regulated in mutant embryos. In collagen gel assays, the number of mesenchymal cells formed is significantly reduced in mutant AV explants compared to that in control explants, suggesting that the reduction of cushion mesenchyme formation in mutants is unlikely secondary to their gross vasculature abnormalities. Using a previously developed immortal endocardial cell line, we showed that Smad4 is required for BMP signaling- stimulated upregulation of Tbx20 and Gata4. Therefore, our data collectively support the cell-autonomous requirement of endocardial Smad4 in regulating AV cushion development. PMID:21089072

Song, Langying; Zhao, Mei; Wu, Bingruo; Zhou, Bin; Wang, Qin; Jiao, Kai

2011-01-01

301

FOG-2 attenuates endothelial-to-mesenchymal transformation in the endocardial cushions of the developing heart.  

PubMed

Development of the heart valves is a complex process that relies on the successful remodeling of endocardial cushions. This process is dependent on a number of transcriptional regulators, including GATA4 and its interacting partner FOG-2. We have previously shown that the endocardial cushions in FOG-2 deficient mice are hyperplastic and fail to remodel appropriately, suggesting a defect late in endocardial cushion development. To elucidate this defect, we examined the later steps in endocardial cushion development including mesenchymal cell proliferation, differentiation, and apoptosis. We also measured myocardialization and endothelial-to-mesenchymal transformation (EMT) using previously described in vitro assays. We found no difference in the ability of the endocardial cushions to undergo myocardialization or in the rates of mesenchymal cell proliferation, differentiation, or apoptosis in the FOG-2 deficient cushions when compared to wild-type controls. However, using a collagen gel invasion assay, we found a 78% increase in outflow tract cushion EMT and a 35% increase in atrioventricular cushion EMT in the FOG-2 deficient mice when compared with wild-type mice. Taken together with GATA4's known role in promoting EMT, these results suggest that FOG-2 functions in cardiac valve formation as an attenuator of EMT by repressing GATA4 activity within the developing endocardial cushions. PMID:17274974

Flagg, Alleda E; Earley, Judy U; Svensson, Eric C

2007-04-01

302

77 FR 75388 - Approval and Promulgation of Air Quality Implementation Plans; State of Colorado; Motor Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...went into effect on January 1, 2006, for 1996 and newer model year vehicles. This action...went into effect on January 1, 2006, for 1996 and newer model year vehicles. We did...to as the ``2006 cutpoints''), for 1996 and newer model year vehicles.\\1\\...

2012-12-20

303

4D metrology of flapping-wing micro air vehicle based on fringe projection  

NASA Astrophysics Data System (ADS)

Inspired by dominant flight of the natural flyers and driven by civilian and military purposes, micro air vehicle (MAV) has been developed so far by passive wing control but still pales in aerodynamic performance. Better understanding of flapping wing flight mechanism is eager to improve MAV's flight performance. In this paper, a simple and effective 4D metrology technique to measure full-field deformation of flapping membrane wing is presented. Based on fringe projection and 3D Fourier analysis, the fast and complex dynamic deformation, including wing rotation and wing stroke, of a flapping wing during its flight can be accurately reconstructed from the deformed fringe patterns recorded by a highspeed camera. An experiment was carried on a flapping-wing MAV with 5-cm span membrane wing beating at 30 Hz, and the results show that this method is effective and will be useful to the aerodynamicist or micro aircraft designer for visualizing high-speed complex wing deformation and consequently aid the design of flapping wing mechanism to enhanced aerodynamic performance.

Zhang, Qican; Huang, Lei; Chin, Yao-Wei; Keong, Lau-Gih; Asundi, Anand

2013-06-01

304

Relationship between vehicle count and particulate air pollution in amman, jordan.  

PubMed

The main objective of this cross-sectional comparative study is to observe the relationship between traffic-related air pollutants, particularly particulate matter (PM) of total suspended particulate (TSP) and PM of size 10 µm (PM10), and vehicle traffic in Amman, Jordan. Two study areas were chosen randomly as a high-polluted area (HPA) and low-polluted area (LPA). The findings indicate that TSP and PM10 were still significantly correlated with traffic count even after controlling for confounding factors (temperature, relative humidity, and wind speed): TSP, r = 0.726, P < .001; PM10, r = 0.719, P < .001). There was a significant positive relationship between traffic count and PM level: TSP, P < .001; PM10, P < .001. Moreover, there was a significant negative relationship between temperature and PM10 level (P = .018). Traffic volume contributed greatly to high concentrations of TSP and PM10 in areas with high traffic count, in addition to the effect of temperature. PMID:22899706

Alnawaiseh, Nedal Awad; Hashim, Jamal Hisham; Md Isa, Zaleha

2015-03-01

305

Measurements and performance prediction of an adaptive wing micro air vehicle  

NASA Astrophysics Data System (ADS)

The mission space requirements imposed on the design of micro air vehicles (MAVs) typically consist of several distinct flight segments that generally conflict: the transit phases of flight require high speeds, while the loiter/surveillance phase requires lower flight velocities. Maximum efficiency must be sought in order to prolong battery life and aircraft endurance. The adaptive wing MAV developed at the University of Arizona features a thin, deformable flying wing with an efficient rudder-elevator control system. The wing camber is varied to accommodate different flight speeds while maintaining a constant total lift at a relatively low angle of attack. A new airfoil was developed from the Selig 5010 that features a small negative pitching moment for pitch stability. Wind tunnel tests were performed and stall angles and best lift-to-drag ratios were analyzed from the data. The wind tunnel data was used in a performance analysis in order to determine the flight speeds and throttle settings for maximum endurance at each camber, as well as the MAV's theoretical minimum and maximum flight speeds. The effectiveness of camber change on flight speed and endurance was examined with promising results; flight speed could be reduced by 25% by increasing the camber from 3 to 9% without any increase in power consumption.

Shkarayev, Sergey V.; Jouse, Wayne C.; Null, William R.; Wagner, Matthew G.

2003-08-01

306

An experimental study of a bio-inspired corrugated airfoil for micro air vehicle applications  

NASA Astrophysics Data System (ADS)

An experimental study was conducted to investigate the aerodynamic characteristics of a bio-inspired corrugated airfoil compared with a smooth-surfaced airfoil and a flat plate at the chord Reynolds number of Re C = 58,000-125,000 to explore the potential applications of such bio-inspired corrugated airfoils for micro air vehicle designs. In addition to measuring the aerodynamic lift and drag forces acting on the tested airfoils, a digital particle image velocimetry system was used to conduct detailed flowfield measurements to quantify the transient behavior of vortex and turbulent flow structures around the airfoils. The measurement result revealed clearly that the corrugated airfoil has better performance over the smooth-surfaced airfoil and the flat plate in providing higher lift and preventing large-scale flow separation and airfoil stall at low Reynolds numbers (Re C < 100,000). While aerodynamic performance of the smooth-surfaced airfoil and the flat plate would vary considerably with the changing of the chord Reynolds numbers, the aerodynamic performance of the corrugated airfoil was found to be almost insensitive to the Reynolds numbers. The detailed flow field measurements were correlated with the aerodynamic force measurement data to elucidate underlying physics to improve our understanding about how and why the corrugation feature found in dragonfly wings holds aerodynamic advantages for low Reynolds number flight applications.

Murphy, Jeffery T.; Hu, Hui

2010-08-01

307

Fuel Cell Propulsion Systems for an All-Electric Personal Air Vehicle  

NASA Technical Reports Server (NTRS)

There is a growing interest in the use of fuel cells as a power source for all-electric aircraft propulsion as a means to substantially reduce or eliminate environmentally harmful emissions. Among the technologies under consideration for these concepts are advanced proton exchange membrane and solid oxide fuel cells, alternative fuels and fuel processing, and fuel storage. This paper summarizes the results of a first-order feasibility study for an all-electric personal air vehicle utilizing a fuel cell-powered propulsion system. A representative aircraft with an internal combustion engine was chosen as a baseline to provide key parameters to the study, including engine power and subsystem mass, fuel storage volume and mass, and aircraft range. The engine, fuel tank, and associated ancillaries were then replaced with a fuel cell subsystem. Various configurations were considered including: a proton exchange membrane (PEM) fuel cell with liquid hydrogen storage; a direct methanol PEM fuel cell; and a direct internal reforming solid oxide fuel cell (SOFC)/turbine hybrid system using liquid methane fuel. Each configuration was compared to the baseline case on a mass and range basis.

Kohout, Lisa L.

2003-01-01

308

Fuel Cell Propulsion Systems for an All-electric Personal Air Vehicle  

NASA Technical Reports Server (NTRS)

There is a growing interest in the use of fuel cells as a power source for all-electric aircraft propulsion as a means to substantially reduce or eliminate environmentally harmful emissions. Among the technologies under consideration for these concepts are advanced proton exchange membrane and solid oxide fuel cells, alternative fuels and fuel processing, and fuel storage. This paper summarizes the results of a first-order feasibility study for an all-electric personal air vehicle utilizing a fuel cell-powered propulsion system. A representative aircraft with an internal combustion engine was chosen as a baseline to provide key parameters to the study, including engine power and subsystem mass, fuel storage volume and mass, and aircraft range. The engine, fuel tank, and associated ancillaries were then replaced with a fuel cell subsystem. Various configurations were considered including: a proton exchange membrane (PEM) fuel cell with liquid hydrogen storage; a direct methanol PEM fuel cell; and a direct internal reforming solid oxide fuel cell (SOFC)/turbine hybrid system using liquid methane fuel. Each configuration was compared to the baseline case on a mass and range basis.

Kohout, Lisa L.; Schmitz, Paul C.

2003-01-01

309

Conservation equations and physical models for hypersonic air flows over the aeroassist flight experiment vehicle  

NASA Technical Reports Server (NTRS)

The code development and application program for the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA), with emphasis directed toward support of the Aeroassist Flight Experiment (AFE) in the near term and Aeroassisted Space Transfer Vehicle (ASTV) design in the long term is reviewed. LAURA is an upwind-biased, point-implicit relaxation algorithm for obtaining the numerical solution to the governing equations for 3-D, viscous, hypersonic flows in chemical and thermal nonequilibrium. The algorithm is derived using a finite volume formulation in which the inviscid components of flux across cell walls are described with Roe's averaging and Harten's entropy fix with second-order corrections based on Yee's Symmetric Total Variation Diminishing scheme. Because of the point-implicit relaxation strategy, the algorithm remains stable at large Courant numbers without the necessity of solving large, block tri-diagonal systems. A single relaxation step depends only on information from nearest neighbors. Predictions for pressure distributions, surface heating, and aerodynamic coefficients compare well with experimental data for Mach 10 flow over an AFE wind tunnel model. Predictions for the hypersonic flow of air in chemical and thermal nonequilibrium over the full scale AFE configuration obtained on a multi-domain grid are discussed.

Gnoffo, Peter A.

1989-01-01

310

Low Dimensional Tools for Flow-Structure Interaction Problems: Application to Micro Air Vehicles  

NASA Technical Reports Server (NTRS)

A low dimensional tool for flow-structure interaction problems based on Proper Orthogonal Decomposition (POD) and modified Linear Stochastic Estimation (mLSE) has been proposed and was applied to a Micro Air Vehicle (MAV) wing. The method utilizes the dynamic strain measurements from the wing to estimate the POD expansion coefficients from which an estimation of the velocity in the wake can be obtained. For this experiment the MAV wing was set at five different angles of attack, from 0 deg to 20 deg. The tunnel velocities varied from 44 to 58 ft/sec with corresponding Reynolds numbers of 46,000 to 70,000. A stereo Particle Image Velocimetry (PIV) system was used to measure the wake of the MAV wing simultaneously with the signals from the twelve dynamic strain gauges mounted on the wing. With 20 out of 2400 POD modes, a reasonable estimation of the flow flow was observed. By increasing the number of POD modes, a better estimation of the flow field will occur. Utilizing the simultaneously sampled strain gauges and flow field measurements in conjunction with mLSE, an estimation of the flow field with lower energy modes is reasonable. With these results, the methodology for estimating the wake flow field from just dynamic strain gauges is validated.

Schmit, Ryan F.; Glauser, Mark N.; Gorton, Susan A.

2003-01-01

311

Air pollutant emissions from vehicles in China under various energy scenarios.  

PubMed

Estimations of air pollutant emissions from vehicles in China under different energy and emission abatement policy scenarios are presented in this paper. Three scenarios are designed: (i) "business as usual" (BAU); (ii) "advanced fuel economy" (AFE); and (iii) "alternative energy replacement" (AER). The CO, VOCs, NOx, PM10, and CO2 emissions are predicted to reach 105.8, 5.9, 7.5, 1.1, and 3522.6 million tons, respectively, in the BAU scenario by 2030. In the AFE scenario, the CO, VOCs, NOx, PM10, and CO2 emissions in 2030 will be abated by 23.8%, 18.6%, 25.3%, 18.2%, and 24.5% respectively compared with the BAU scenario. In the AER scenario, the CO and VOCs in 2030 will be further reduced by 15.9% and 6.1% respectively, while NOx, PM10, and CO2 will be increased by 10.7%, 33.3%, and 2.0% compared with AFE. In conclusion, our models indicate that the emission abatement policies introduced by governmental institutions are potentially viable, as long as they are effectively implemented. PMID:23500823

Zhang, Qingyu; Sun, Guojin; Fang, Simai; Tian, Weili; Li, Xiaoxiao; Wang, Huiyu

2013-04-15

312

Multisensor 3D tracking for counter small unmanned air vehicles (CSUAV)  

NASA Astrophysics Data System (ADS)

A variety of unmanned air vehicles (UAVs) have been developed for both military and civilian use. The typical large UAV is typically state owned, whereas small UAVs (SUAVs) may be in the form of remote controlled aircraft that are widely available. The potential threat of these SUAVs to both the military and civilian populace has led to research efforts to counter these assets via track, ID, and attack. Difficulties arise from the small size and low radar cross section when attempting to detect and track these targets with a single sensor such as radar or video cameras. In addition, clutter objects make accurate ID difficult without very high resolution data, leading to the use of an acoustic array to support this function. This paper presents a multi-sensor architecture that exploits sensor modes including EO/IR cameras, an acoustic array, and future inclusion of a radar. A sensor resource management concept is presented along with preliminary results from three of the sensors.

Vasquez, Juan R.; Tarplee, Kyle M.; Case, Ellen E.; Zelnio, Anne M.; Rigling, Brian D.

2008-04-01

313

Design Evolution and Performance Characterization of the GTX Air-Breathing Launch Vehicle Inlet  

NASA Technical Reports Server (NTRS)

The design and analysis of a second version of the inlet for the GTX rocket-based combine-cycle launch vehicle is discussed. The previous design did not achieve its predicted performance levels due to excessive turning of low-momentum comer flows and local over-contraction due to asymmetric end-walls. This design attempts to remove these problems by reducing the spike half-angle to 10- from 12-degrees and by implementing true plane of symmetry end-walls. Axisymmetric Reynolds-Averaged Navier-Stokes simulations using both perfect gas and real gas, finite rate chemistry, assumptions were performed to aid in the design process and to create a comprehensive database of inlet performance. The inlet design, which operates over the entire air-breathing Mach number range from 0 to 12, and the performance database are presented. The performance database, for use in cycle analysis, includes predictions of mass capture, pressure recovery, throat Mach number, drag force, and heat load, for the entire Mach range. Results of the computations are compared with experimental data to validate the performance database.

DeBonis, J. R.; Steffen, C. J., Jr.; Rice, T.; Trefny, C. J.

2002-01-01

314

Dual rotor single- stator axial air gap PMSM motor/generator drive for high torque vehicles applications  

NASA Astrophysics Data System (ADS)

The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors, destined for hybrid electric vehicles (HEV) and military vehicles applications. The proposed topologies and the magneto-motive force analysis are the core of the paper.

Tutelea, L. N.; Deaconu, S. I.; Boldea, I.; Popa, G. N.

2014-03-01

315

Air-breathing hypersonic vehicle guidance and control studies: An integrated trajectory/control analysis methodology, phase 2  

NASA Technical Reports Server (NTRS)

An integrated trajectory/control analysis algorithm has been used to generate trajectories and desired control strategies for two different hypersonic air-breathing vehicle models and orbit targets. Both models used cubic spline curve fit tabulated winged-cone accelerator vehicle representations. Near-fuel-optimal, horizontal takeoff trajectories, imposing a dynamic pressure limit of 1000 psf, were developed. The first model analysis case involved a polar orbit and included the dynamic effects of using elevons to maintain longitudinal trim. Analysis results indicated problems with the adequacy of the propulsion model and highlighted dynamic pressure/altitude instabilities when using vehicle angle of attack as a control variable. Also, the magnitude of computed elevon deflections to maintain trim suggested a need for alternative pitch moment management strategies. The second analysis case was reformulated to use vehicle pitch attitude relative to the local vertical as the control variable. A new, more realistic, air-breathing propulsion model was incorporated. Pitch trim calculations were dropped and an equatorial orbit was specified. Changes in flight characteristics due to the new propulsion model have been identified. Flight regimes demanding rapid attitude changes have been noted. Also, some issues that would affect design of closed-loop controllers were ascertained.

Hattis, Philip D.; Malchow, Harvey L.

1992-01-01

316

Experimental investigation of some aspects of insect-like flapping flight aerodynamics for application to micro air vehicles  

Microsoft Academic Search

Insect-like flapping flight offers a power-efficient and highly manoeuvrable basis for micro air vehicles for indoor applications.\\u000a Some aspects of the aerodynamics associated with the sweeping phase of insect wing kinematics are examined by making particle\\u000a image velocimetry measurements on a rotating wing immersed in a tank of seeded water. The work is motivated by the paucity\\u000a of data with

Salman A. Ansari; Nathan Phillips; Graham Stabler; Peter C. Wilkins; Rafa? ?bikowski; Kevin Knowles

2009-01-01

317

Two-frame structure from motion using optical flow probability distributions for unmanned air vehicle obstacle avoidance  

Microsoft Academic Search

See-and-avoid behaviors are an essential part of autonomous navigation for Unmanned Air Vehicles (UAVs). To be fully autonomous,\\u000a a UAV must be able to navigate complex urban and near-earth environments and detect and avoid imminent collisions. While there\\u000a have been significant research efforts in robotic navigation and obstacle avoidance during the past few years, this previous\\u000a work has not focused

Dah-Jye Lee; Paul C. Merrell; Zhaoyi Wei; Brent E. Nelson

2010-01-01

318

Modeling dispersions in initial conditions for air-launched rockets and their effect on vehicle performance  

E-print Network

Growing interest in air-launched rockets as a method for lofting satellites into orbit motivates the need to investigate the unique challenges that air launch presents. This thesis explores how uncertainties in an air-launched ...

Beerer, Ingrid Mary

2013-01-01

319

9 CFR 3.62 - Primary conveyances (motor vehicle, rail, air, and marine).  

Code of Federal Regulations, 2014 CFR

...shall be mechanically sound and provide fresh air by means of windows, doors, vents, or air conditioning so as to minimize drafts, odors...condensation. Auxiliary ventilation, such as fans, blowers, or air conditioners, shall be used in any cargo...

2014-01-01

320

9 CFR 3.62 - Primary conveyances (motor vehicle, rail, air, and marine).  

Code of Federal Regulations, 2010 CFR

...shall be mechanically sound and provide fresh air by means of windows, doors, vents, or air conditioning so as to minimize drafts, odors...condensation. Auxiliary ventilation, such as fans, blowers, or air conditioners, shall be used in any cargo...

2010-01-01

321

9 CFR 3.62 - Primary conveyances (motor vehicle, rail, air, and marine).  

Code of Federal Regulations, 2012 CFR

...shall be mechanically sound and provide fresh air by means of windows, doors, vents, or air conditioning so as to minimize drafts, odors...condensation. Auxiliary ventilation, such as fans, blowers, or air conditioners, shall be used in any cargo...

2012-01-01

322

9 CFR 3.62 - Primary conveyances (motor vehicle, rail, air, and marine).  

Code of Federal Regulations, 2011 CFR

...shall be mechanically sound and provide fresh air by means of windows, doors, vents, or air conditioning so as to minimize drafts, odors...condensation. Auxiliary ventilation, such as fans, blowers, or air conditioners, shall be used in any cargo...

2011-01-01

323

9 CFR 3.62 - Primary conveyances (motor vehicle, rail, air, and marine).  

Code of Federal Regulations, 2013 CFR

...shall be mechanically sound and provide fresh air by means of windows, doors, vents, or air conditioning so as to minimize drafts, odors...condensation. Auxiliary ventilation, such as fans, blowers, or air conditioners, shall be used in any cargo...

2013-01-01

324

Emerging Fuel Cell Technology Being Developed: Offers Many Benefits to Air Vehicles  

NASA Technical Reports Server (NTRS)

Fuel cells, which have recently received considerable attention for terrestrial applications ranging from automobiles to stationary power generation, may enable new aerospace missions as well as offer fuel savings, quiet operations, and reduced emissions for current and future aircraft. NASA has extensive experience with fuel cells, having used them on manned space flight systems over four decades. Consequently, the NASA Glenn Research Center has initiated an effort to investigate and develop fuel cell technologies for multiple aerospace applications. Two promising fuel cell types are the proton exchange membrane (PEM) and solid oxide fuel cell (SOFC). PEM technology, first used on the Gemini spacecraft in the sixties, remained unutilized thereafter until the automotive industry recently recognized the potential. PEM fuel cells are low-temperature devices offering quick startup time but requiring relatively pure hydrogen fuel. In contrast, SOFCs operate at high temperatures and tolerate higher levels of impurities. This flexibility allows SOFCs to use hydrocarbon fuels, which is an important factor considering our current liquid petroleum infrastructure. However, depending on the specific application, either PEM or SOFC can be attractive. As only NASA can, the Agency is pursuing fuel cell technology for civil uninhabited aerial vehicles (UAVs) because it offers enhanced scientific capabilities, including enabling highaltitude, long-endurance missions. The NASA Helios aircraft demonstrated altitudes approaching 100,000 ft using solar power in 2001, and future plans include the development of a regenerative PEM fuel cell to provide nighttime power. Unique to NASA's mission, the high-altitude aircraft application requires the PEM fuel cell to operate on pure oxygen, instead of the air typical of terrestrial applications.

Walker, James F.; Civinskas, Kestutis C.

2004-01-01

325

The Role of Design-of-Experiments in Managing Flow in Compact Air Vehicle Inlets  

NASA Technical Reports Server (NTRS)

It is the purpose of this study to demonstrate the viability and economy of Design-of-Experiments methodologies to arrive at microscale secondary flow control array designs that maintain optimal inlet performance over a wide range of the mission variables and to explore how these statistical methods provide a better understanding of the management of flow in compact air vehicle inlets. These statistical design concepts were used to investigate the robustness properties of low unit strength micro-effector arrays. Low unit strength micro-effectors are micro-vanes set at very low angles-of-incidence with very long chord lengths. They were designed to influence the near wall inlet flow over an extended streamwise distance, and their advantage lies in low total pressure loss and high effectiveness in managing engine face distortion. The term robustness is used in this paper in the same sense as it is used in the industrial problem solving community. It refers to minimizing the effects of the hard-to-control factors that influence the development of a product or process. In Robustness Engineering, the effects of the hard-to-control factors are often called noise , and the hard-to-control factors themselves are referred to as the environmental variables or sometimes as the Taguchi noise variables. Hence Robust Optimization refers to minimizing the effects of the environmental or noise variables on the development (design) of a product or process. In the management of flow in compact inlets, the environmental or noise variables can be identified with the mission variables. Therefore this paper formulates a statistical design methodology that minimizes the impact of variations in the mission variables on inlet performance and demonstrates that these statistical design concepts can lead to simpler inlet flow management systems.

Anderson, Bernhard H.; Miller, Daniel N.; Gridley, Marvin C.; Agrell, Johan

2003-01-01

326

Material properties for TR-55 and silicone elastomeric cushions  

SciTech Connect

The notation of finite elastic theory for compressible rubber-like materials is introduced. The mechanics of data reduction, needed to determine the parameters of the theory, are displayed. the material properties of TR-55 rubber and silicone rubber cushions are obtained. The constitutive relation, with the material properties, correlates all uniaxial compressive data to a high degree of accuracy. The force-deformation relations of thin sheets of TR-55 in compression have been obtained. Further studies, both theoretical and experimental, on TR-55 thin sheets are needed to determine the force-deformation relation. 11 figures.

Feng, W.W.; Albertson, S.L.; Rosinsky, R.W.

1982-10-05

327

Membrane-based air composition control for light-duty diesel vehicles : a benefit and cost assessment.  

SciTech Connect

This report presents the methodologies and results of a study conducted by Argonne National Laboratory (Argonne) to assess the benefits and costs of several membrane-based technologies. The technologies evaluated will be used in automotive emissions-control and performance-enhancement systems incorporated into light-duty diesel vehicle engines. Such engines are among the technologies that are being considered to power vehicles developed under the government-industry Partnership for a New Generation of Vehicles (PNGV). Emissions of nitrogen oxides (NO{sub x}) from diesel engines have long been considered a barrier to use of diesels in urban areas. Recently, particulate matter (PM) emissions have also become an area of increased concern because of new regulations regarding emissions of particulate matter measuring 2.5 micrometers or less (PM2.5). Particulates are of special concern for diesel engines in the PNGV program; the program has a research goal of 0.01 gram per mile (g/mi) of particulate matter emissions under the Federal Test Procedure (FTP) cycle. This extremely low level (one-fourth the level of the Tier II standard) could threaten the viability of using diesel engines as stand-alone powerplants or in hybrid-electric vehicles. The techniques analyzed in this study can reduce NO{sub x} and particulate emissions and even increase the power density of the diesel engines used in light-duty diesel vehicles. For nearly a decade, Argonne has been evaluating membrane-based methods to control the composition of air used in combustion. Membranes are the only practical method of modifying air composition for on-board use. The applicability of the technique depends strongly on both the technical and economic feasibility of implementing it on a vehicle. Over the past 10 years, significant technical advances have been made in the development of air-separation membranes. Researchers have developed and commercialized novel membrane materials that can efficiently separate air at the concentrations required for vehicle applications and have developed compact membrane modules that can be incorporated into vehicle design. Previous analysis by Argonne and others has demonstrated the effectiveness of oxygen enrichment at reducing PM, smoke, hydrocarbon (HC), and carbon monoxide (CO) emissions while increasing engine power output. Under appropriate oxygen-enriched operating conditions, diesel engines have achieved a net increase of 10-20% in power density and a decrease of 30-60% in PM emissions. Nitrogen-enriched air can be used as an alternative to exhaust gas recirculation to control NO{sub x} emissions and can also be used to generate a monatomic nitrogen plasma for exhaust post-treatment to reduce emissions of NO{sub x}. Argonne has recently identified an operating regime that can simultaneously reduce NO{sub x} and PM while increasing power output when oxygen-enriched combustion air is used. This promising technique, which will be verified by additional experimental work at Argonne (using a range of engine sizes), will require the use of membranes similar to those analyzed in this study.

Poola, R.; Stork, K.

1998-11-09

328

Polymer-Cushioned Bilayers. I. A Structural Study of Various Preparation Methods Using Neutron Reflectometry  

E-print Network

Polymer-Cushioned Bilayers. I. A Structural Study of Various Preparation Methods Using Neutron of preparing polymer-cushioned lipid bilayers. Four different techniques to deposit adsorption onto a previously dried polymer layer; 2) vesicle adsorption onto a bare substrate, followed

Wong, Joyce

329

An efficient fluid-structure interaction method for conceptual design of flexible micro air vehicle wings: Development, comparison, and application  

NASA Astrophysics Data System (ADS)

This thesis summarizes the development, comparison, and applications of an efficient fluid-structure interaction method capable of simulating the effects that wing flexibility has on micro air vehicle (MAV) performance. Micro air vehicles wing designs often incorporate flexible wing structures that mimic the skeleton / membrane designs found in natural flyers such as bats and insects. However, accurate performance prediction for these wings requires the coupling of the simulation of the fluid physics around the wing and the simulation of the structural deformation. These fluid-structure interaction (FSI) simulations are often accomplished using high fidelity, computationally expensive techniques such as computational fluid dynamics (CFD) for the fluid physics and nonlinear finite element analysis (FEA) for the structural simulation. The main drawback of these methods, especially for use simulating vehicles that are able to be manufactured relatively quickly, is that the computational cost required to perform relevant trade studies on the design is prohibitively large and time-consuming. The main goal of this research is the development of a coupled fluid-structure interaction method computationally efficient and accurate enough to be used for conceptual design of micro air vehicles. An advanced potential flow model is used to calculate aerodynamic performance and loading, while a simplified finite element structural model using frame and shell elements calculates the wing deflection due to aerodynamic loading. The contents of this thesis include a literature survey of current approaches, an introduction to the efficient FSI formulation, comparison of the presented FSI method with higher-fidelity simulation methods, demonstrations of the method's capability for tradeoff and optimization studies, and an overview of contributions to a nonlinear dynamic algorithm for the simulation of flapping flight.

Combes, Thomas P.

330

Extracting micro air vehicles aerodynamic forces and coefficients in free flight using visual motion tracking techniques  

NASA Astrophysics Data System (ADS)

This paper describes a methodology to extract aerial vehicles’ aerodynamic characteristics from visually tracked trajectory data. The technique is being developed to study the aerodynamics of centimeter-scale aircraft and develop flight simulation models. Centimeter-scale aircraft remains a largely unstudied domain of aerodynamics, for which traditional techniques like wind tunnels and computational fluid dynamics have not yet been fully adapted and validated. The methodology takes advantage of recent progress in commercial, vision-based, motion-tracking systems. This system dispenses from on-board navigation sensors and enables indoor flight testing under controlled atmospheric conditions. Given the configuration of retro-reflective markers affixed onto the aerial vehicle, the vehicle’s six degrees-of-freedom motion can be determined in real time. Under disturbance-free conditions, the aerodynamic forces and moments can be determined from the vehicle’s inertial acceleration, and furthermore, for a fixed-wing vehicle, the aerodynamic angles can be plotted from the vehicle’s kinematics. By combining this information, we can determine the temporal evolution of the aerodynamic coefficients, as they change throughout a trajectory. An attractive feature of this technique is that trajectories are not limited to equilibrium conditions but can include non-equilibrium, maneuvering flight. Whereas in traditional wind-tunnel experiments, the operating conditions are set by the experimenter, here, the aerodynamic conditions are driven by the vehicle’s own dynamics. As a result, this methodology could be useful for characterizing the unsteady aerodynamics effects and their coupling with the aircraft flight dynamics, providing insight into aerodynamic phenomena taking place at centimeter scale flight.

Mettler, B. F.

2010-09-01

331

Investigation of the Landing Characteristics of a Re-entry Vehicle Having a Canted Multiple Air Bag Load Alleviation System  

NASA Technical Reports Server (NTRS)

An investigation was made to determine the landing-impact characteristics of a reentry vehicle having a multiple-air-bag load-alleviation system. A 1/16-scale dynamic model having four canted air bags was tested at flight-path angles of 90 degrees (vertical), 45 degrees, and 27 degrees for a parachute or paraglider vertical letdown velocity of 30 feet per second (full scale). Landings were made on concrete at attitudes ranging from -l5 degrees to 20 degrees. The friction coefficient between the model heat shield and the concrete was approximately 0.4. An aluminum diaphragm, designed to rupture at 10.8 pounds per square inch gage, was used to maintain initial pressure in the air bags for a short time period.

McGehee, John R.; Stubbs, Sandy M.

1963-01-01

332

Testing of aircraft passenger seat cushion material, full scale. Data, volume 2  

NASA Technical Reports Server (NTRS)

Burn characteristics of presently used and proposed seat cushion materials and types of constructions were determined. Eight different seat cushion configurations were subjected to full scale burn tests. Each cushion configuration was tested twice for a total of 16 tests. Two different fire sources were used: Jet A-fuel for eight tests, and a radiant energy source with propane flame for eight tests. Data were recorded for smoke density, cushion temperatures, radiant heat flux, animal response to combustion products, rate of weight loss of test specimens, cabin temperature, and type and content of gas within the cabin. When compared to existing seat cushions, the test specimens incorporating a fire barrier and those fabricated from advanced materials, using improved construction methods, exhibited significantly greater fire resistance. Flammability comparison tests were conducted upon one fire blocking configuration and one polyimide configuration.

Schutter, K. J.; Gaume, J. G.; Duskin, F. E.

1980-01-01

333

79 FR 38787 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Low Emission Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...economy, the Corporate Average Fuel Economy (CAFE) standards...reduce GHG emissions and improve fuel economy for light-duty vehicles...footprint value (related to the size of the vehicle). Generally, the...comply with the gas mileage, or fuel economy, standards set by...

2014-07-09

334

Attitude estimation and maneuvering for autonomous obstacle avoidance by miniature air vehicles  

Microsoft Academic Search

Utilizing the Euler-Rodrigues symmetric parameters (attitude quaternion) to describe vehicle orientation, we develop a multiplicative, nonlinear (extended) variation of the Kalman filter (MEKF) to fuse data from low-cost sensors. The sensor suite is comprised of gyroscopes, accelerometers, and a GPS receiver. In contrast to the common approach of using the complete vehicle attitude as the quantities to be estimated, our

James K. Hall

2009-01-01

335

Test methodology for evaluation of fireworthy aircraft seat cushions  

NASA Technical Reports Server (NTRS)

Aircraft seat materials were evaluated in terms of their thermal performance. The materials were evaluated using (a) thermogravimetric analysis, (b) differential scanning calorimetry, (c) a modified NBS smoke chamber to determine the rate of mass loss and (d) the NASA T-3 apparatus to determine the thermal efficiency. In this paper, the modified NBS smoke chamber will be described in detail since it provided the most conclusive results. The NBS smoke chamber was modified to measure the weight loss of materials when exposed to a radiant heat source over the range of 2.5 to 7.5 W/cm sq. This chamber has been utilized to evaluate the thermal performance of various heat blocking layers utilized to protect the polyurethane cushioning foam used in aircraft seats. Various kinds of heat blocking layers were evaluated by monitoring the weight loss of miniature seat cushions when exposed to the radiant heat. The effectiveness of aluminized heat blocking systems was demonstrated when compared to conventional heat blocking layers such as neoprene. All heat blocking systems showed good fire protection capabilities when compared to the state-of-the-art, i.e., wool-nylon over polyurethane foam.

Kourtides, D. A.; Parker, J. A.

1982-01-01

336

9 CFR 3.114 - Primary conveyances (motor vehicle, rail, air and marine).  

Code of Federal Regulations, 2012 CFR

...cargo spaces that have a supply of air sufficient for each live animal contained within. Primary transport enclosures must be positioned...will have access to sufficient air. (d) Primary transport enclosures must be...

2012-01-01

337

9 CFR 3.114 - Primary conveyances (motor vehicle, rail, air and marine).  

Code of Federal Regulations, 2011 CFR

...cargo spaces that have a supply of air sufficient for each live animal contained within. Primary transport enclosures must be positioned...will have access to sufficient air. (d) Primary transport enclosures must be...

2011-01-01

338

9 CFR 3.114 - Primary conveyances (motor vehicle, rail, air and marine).  

Code of Federal Regulations, 2014 CFR

...cargo spaces that have a supply of air sufficient for each live animal contained within. Primary transport enclosures must be positioned...will have access to sufficient air. (d) Primary transport enclosures must be...

2014-01-01

339

9 CFR 3.114 - Primary conveyances (motor vehicle, rail, air and marine).  

Code of Federal Regulations, 2013 CFR

...cargo spaces that have a supply of air sufficient for each live animal contained within. Primary transport enclosures must be positioned...will have access to sufficient air. (d) Primary transport enclosures must be...

2013-01-01

340

9 CFR 3.114 - Primary conveyances (motor vehicle, rail, air and marine).  

Code of Federal Regulations, 2010 CFR

...cargo spaces that have a supply of air sufficient for each live animal contained within. Primary transport enclosures must be positioned...will have access to sufficient air. (d) Primary transport enclosures must be...

2010-01-01

341

Cooperative Radar Jamming for Groups of Unmanned Air Vehicles Jongrae Kim  

E-print Network

signal. Jamming is often used to conceal aircraft from the radars that guide Surface-to-Air Missiles and cooperates in their use of jamming resources to prevent being tracked by Surface-to-Air Missile (SAM

Hespanha, João Pedro

342

Air quality impacts of plug-in hybrid electric vehicles in Texas: evaluating three battery charging scenarios  

NASA Astrophysics Data System (ADS)

The air quality impacts of replacing approximately 20% of the gasoline-powered light duty vehicle miles traveled (VMT) with electric VMT by the year 2018 were examined for four major cities in Texas: Dallas/Ft Worth, Houston, Austin, and San Antonio. Plug-in hybrid electric vehicle (PHEV) charging was assumed to occur on the electric grid controlled by the Electricity Reliability Council of Texas (ERCOT), and three charging scenarios were examined: nighttime charging, charging to maximize battery life, and charging to maximize driver convenience. A subset of electricity generating units (EGUs) in Texas that were found to contribute the majority of the electricity generation needed to charge PHEVs at the times of day associated with each scenario was modeled using a regional photochemical model (CAMx). The net impacts of the PHEVs on the emissions of precursors to the formation of ozone included an increase in NOx emissions from EGUs during times of day when the vehicle is charging, and a decrease in NOx from mobile emissions. The changes in maximum daily 8 h ozone concentrations and average exposure potential at twelve air quality monitors in Texas were predicted on the basis of these changes in NOx emissions. For all scenarios, at all monitors, the impact of changes in vehicular emissions, rather than EGU emissions, dominated the ozone impact. In general, PHEVs lead to an increase in ozone during nighttime hours (due to decreased scavenging from both vehicles and EGU stacks) and a decrease in ozone during daytime hours. A few monitors showed a larger increase in ozone for the convenience charging scenario versus the other two scenarios. Additionally, cumulative ozone exposure results indicate that nighttime charging is most likely to reduce a measure of ozone exposure potential versus the other two scenarios.

Thompson, Tammy M.; King, Carey W.; Allen, David T.; Webber, Michael E.

2011-04-01

343

9 CFR 3.138 - Primary conveyances (motor vehicle, rail, air, and marine).  

Code of Federal Regulations, 2010 CFR

...Handling, Care, Treatment, and Transportation of Warmblooded Animals Other Than Dogs, Cats, Rabbits, Hamsters, Guinea Pigs, Nonhuman Primates, and Marine Mammals Transportation Standards § 3.138 Primary conveyances (motor vehicle,...

2010-01-01

344

International Conference 'Transport and Air Pollution' 2008, Graz EMISSION FACTOR MODELLING FOR LIGHT VEHICLES  

E-print Network

- 1 - 16th International Conference 'Transport and Air Pollution' 2008, Graz EMISSION FACTOR in Europe: The European MEET (Methodologies for Estimating air pollutant Emissions from Transport) project. Transport and Air Pollution, Graz : Austria (2008)" #12;- 2 - 16th International Conference 'Transport

Paris-Sud XI, Université de

345

[Risk for environment-induced diseases due to air pollution from motor vehicles in road-patrol officers].  

PubMed

The paper describes risk factors for environment-induced diseases in road-patrol (RP) officers under the existing working conditions: noise and chemical ambient air pollution from motor vehicles. There is evidence for a significant increase in the incidence of diseases of the cardiovascular and nervous system, sense organs, digestive and endocrine metabolic systems in the State Road Safety Inspectorate officers who are directly engaged in traffic management. Potential and real risks from motor transport to the health of RP roads have been estimated. Recommendations on optimizing the working conditions are given. PMID:20734739

Mikha?lichenko, K Iu; Kas'ianenko, A A; Shchelkunova, I G; Grechko, A V

2010-01-01

346

A study of the dynamics of low energy cushioning material using scale models  

E-print Network

Ratio of the true acceleration to that of an ideal cushion Mass dropped on the cushion None FT L Velocity at impact of mass on the cushion LT V/h Initial strain rate of the material Weight of the dropper Peak acceleration of the dropper LT vn1... machined to a 6 x 6 -in. square. The total height of the dropper was 7 inches from face to top of bearing cases. The total weight with accelerometer and rods was 7. 3 pounds. Holes were drilled and tapped on the top surface of the head for weight...

Woolam, William Edward

1965-01-01

347

Pair plasma cushions in the hole-boring scenario  

NASA Astrophysics Data System (ADS)

Pulses from a 10 PW laser are predicted to produce large numbers of gamma-rays and electron-positron pairs on hitting a solid target. However, a pair plasma, if it accumulates in front of the target, may partially shield it from the pulse. Using stationary, one-dimensional solutions of the two-fluid (electron-positron) and Maxwell equations, including a classical radiation reaction term, we examine this effect in the hole-boring scenario. We find the collective effects of a pair plasma ‘cushion’ substantially reduce the reflectivity, converting the absorbed flux into high-energy gamma-rays. There is also a modest increase in the laser intensity needed to achieve threshold for a non-linear pair cascade.

Kirk, J. G.; Bell, A. R.; Ridgers, C. P.

2013-09-01

348

Ascent performance of an air-breathing horizontal-takeoff launch vehicle  

NASA Technical Reports Server (NTRS)

Simulations are conducted to investigate a proposed NASA launch vehicle that is fully reusable, takes off horizontally, and uses airbreathing propulsion in a single stage. The propulsion model is based on a cycle analysis method, and the vehicle is assumed to be a rigid structure with distributed fuel, operating under a range of atmospheric conditions. The program to optimize simulated trajectories (POST) is modified to include a predictor-corrector guidance capability and then used to generate the trajectories. Significant errors are encountered during the unpowered coast phase due to uncertainty in the atmospheric density profile. The amount of ascent propellant needed is shown to be directly related to the thrust-vector angle and the location of the center of gravity of the vehicle because of the importance of aim-drag losses to total ideal velocity.

Powell, Richard W.; Shaughnessy, John D.; Cruz, Christopher I.; Naftel, J. C.

1991-01-01

349

Hover and wind-tunnel testing of shrouded rotors for improved micro air vehicle design  

NASA Astrophysics Data System (ADS)

The shrouded-rotor configuration has emerged as the most popular choice for rotary-wing Micro Air Vehicles (MAVs), because of the inherent safety of the design and the potential for significant performance improvements. However, traditional design philosophies based on experience with large-scale ducted propellers may not apply to the low-Reynolds-number (˜20,000) regime in which MAVs operate. An experimental investigation of the effects of varying the shroud profile shape on the performance of MAV-scale shrouded rotors has therefore been conducted. Hover tests were performed on seventeen models with a nominal rotor diameter of 16 cm (6.3 in) and various values of diffuser expansion angle, diffuser length, inlet lip radius and blade tip clearance, at various rotor collective angles. Compared to the baseline open rotor, the shrouded rotors showed increases in thrust by up to 94%, at the same power consumption, or reductions in power by up to 62% at the same thrust. These improvements surpass those predicted by momentum theory, due to the additional effect of the shrouds in reducing the non-ideal power losses of the rotor. Increasing the lip radius and decreasing the blade tip clearance caused performance to improve, while optimal values of diffuser angle and length were found to be 10 and 50% of the shroud throat diameter, respectively. With the exception of the lip radius, the effects of changing any of the shrouded-rotor parameters on performance became more pronounced as the values of the other parameters were changed to degrade performance. Measurements were also made of the wake velocity profiles and the shroud surface pressure distributions. The uniformity of the wake was improved by the presence of the shrouds and by decreasing the blade tip clearance, resulting in lower induced power losses. For high net shroud thrust, a favorable pressure distribution over the inlet was seen to be more important than in the diffuser. Strong suction pressures were observed above the blade-passage region on the inlet surface; taking advantage of this phenomenon could enable further increases in thrust. However, trade studies showed that, for a given overall aircraft size limitation, and ignoring considerations of the safety benefits of a shroud, a larger-diameter open rotor is more likely to give better performance than a smaller-diameter shrouded rotor. The open rotor and a single shrouded-rotor model were subsequently tested at a single collective in translational flight, at angles of attack from 0° (axial flow) to 90° (edgewise flow), and at various advance ratios. In axial flow, the net thrust and the power consumption of the shrouded rotor were lower than those of the open rotor. In edgewise flow, the shrouded rotor produced greater thrust than the open rotor, while consuming less power. Measurements of the shroud surface pressure distributions illustrated the extreme longitudinal asymmetry of the flow around the shroud, with consequent pitch moments much greater than those exerted on the open rotor. Except at low airspeeds and high angles of attack, the static pressure in the wake did not reach ambient atmospheric values at the diffuser exit plane; this challenges the validity of the fundamental assumption of the simple-momentum-theory flow model for short-chord shrouds in translational flight.

Pereira, Jason L.

350

On aerodynamic modelling of an insect-like flapping wing in hover for micro air vehicles.  

PubMed

This theoretical paper discusses recent advances in the fluid dynamics of insect and micro air vehicle (MAV) flight and considers theoretical analyses necessary for their future development. The main purpose is to propose a new conceptual framework and, within this framework, two analytic approaches to aerodynamic modelling of an insect-like flapping wing in hover in the context of MAVs. The motion involved is periodic and is composed of two half-cycles (downstroke and upstroke) which, in hover, are mirror images of each other. The downstroke begins with the wing in the uppermost and rearmost position and then sweeps forward while pitching up and plunging down. At the end of the half-cycle, the wing flips, so that the leading edge points backwards and the wing's lower surface becomes its upper side. The upstroke then follows by mirroring the downstroke kinematics and executing them in the opposite direction. Phenomenologically, the interpretation of the flow dynamics involved, and adopted here, is based on recent experimental evidence obtained by biologists from insect flight and related mechanical models. It is assumed that the flow is incompressible, has low Reynolds number and is laminar, and that two factors dominate: (i) forces generated by the bound leading-edge vortex, which models flow separation; and (ii) forces due to the attached part of the flow generated by the periodic pitching, plunging and sweeping. The first of these resembles the analogous phenomenon observed on sharp-edged delta wings and is treated as such. The second contribution is similar to the unsteady aerodynamics of attached flow on helicopter rotor blades and is interpreted accordingly. Theoretically, the fluid dynamic description is based on: (i) the superposition of the unsteady contributions of wing pitching, plunging and sweeping; and (ii) adding corrections due to the bound leading-edge vortex and wake distortion. Viscosity is accounted for indirectly by imposing the Kutta condition on the trailing edge and including the influence of the vortical structure on the leading edge. Mathematically, two analytic approaches are proposed. The first derives all the quantities of interest from the notion of circulation and leads to tractable integral equations. This is an application of the von Kármán-Sears unsteady wing theory and its nonlinear extensions due to McCune and Tavares; the latter can account for the bound leading-edge vortex and wake distortion. The second approach uses the velocity potential as the central concept and leads to relatively simple ordinary differential equations. It is a combination of two techniques: (i) unsteady aerodynamic modelling of attached flow on helicopter rotor blades; and (ii) Polhamus's leading-edge suction analogy. The first of these involves both frequency-domain (Theodorsen style) and time-domain (indicial) methods, including the effects of wing sweeping and returning wake. The second is a nonlinear correction accounting for the bound leading-edge vortex. Connections of the proposed framework with control engineering and aeroelasticity are pointed out. PMID:16210181

Zbikowski, Rafa?

2002-02-15

351

Fundamental understanding of the cycloidal-rotor concept for micro air vehicle applications  

NASA Astrophysics Data System (ADS)

The cycloidal-rotor (cyclorotor) is a revolutionary flying concept which has not been systematically studied in the past. Therefore, in the current research, the viability of the cyclorotor concept for powering a hover-capable micro-air-vehicle (MAV) was examined through both experiments and analysis. Experimental study included both performance and flow field measurements on a cyclorotor of span and diameter equal to 6 inches. The analysis developed was an unsteady large deformation aeroelastic analysis to predict the blade loads and average aerodynamic performance of the cyclorotor. The flightworthiness of the cyclorotor concept was also demonstrated through two cyclocopters capable of tethered hover. Systematic performance measurements have been conducted to understand the effect of the rotational speed, blade airfoil profile, blade flexibility, blade pitching amplitude (symmetric and asymmetric blade pitching), pitching axis location, number of blades with constant chord (varying solidity), and number of blades at same rotor solidity (varying blade chord) on the aerodynamic performance of the cyclorotor. Force measurements showed the presence of a significant sideward force on the cyclorotor (along with the vertical force), analogous to that found on a spinning circular cylinder. Particle image velocimetry (PIV) measurements made in the wake of the cyclorotor provided evidence of a significant wake skewness, which was produced by the sideward force. PIV measurements also captured the blade tip vortices and a large region of rotational flow inside the rotor. The thrust produced by the cyclorotor was found to increase until a blade pitch amplitude of 45° was reached without showing any signs of blade stall. This behavior was also explained using the PIV measurements, which indicated evidence of a stall delay as well as possible increase in lift on the blades from the presence of a leading edge vortex. Higher blade pitch amplitudes also improved the power loading (thrust/power) of the cyclorotor. When compared to the flat-plate blades, the NACA 0010 blades produced the highest values of thrust at all blade pitching amplitudes. The NACA blades also produced higher power loading than the flat plate blades. However, the reverse NACA 0010 blades produced better power loadings at lower pitching amplitudes, even though at high pitch amplitudes, regular NACA blades performed better. Among the three NACA sections (NACA 0006, NACA 0010 and NACA 0015) tested on the cyclorotor, NACA 0015 had the highest power loading followed by NACA 0010 and then NACA 0006. The power loading also increased when using more blades with constant chord (increasing solidity); this observation was found over a wide range of blade pitching amplitudes. Asymmetric pitching with higher pitch angle at the top of the blade trajectory than at the bottom produced better power loading. The chordwise op timum pitching axis location was approximately 25--35% of the blade chord. For a constant solidity, the rotor with fewer number of blades produced higher thrust and the 2-bladed rotor had the best power loading. Any significant bending and torsional flexibility of the blades had a deleterious effect on performance. The optimized cyclorotor had slightly higher power loading when compared to a conventional micro-rotor when operated at the same disk loading. The optimum configuration based on all the tests was a 4-bladed rotor using 1.3 inch chord NACA 0015 blade section with an asymmetric pitching of 45° at top and 25° at bottom with the pitching axis at 25% chord. The aeroelastic analysis was performed using two approaches, one using a second-order non-linear beam FEM analysis for moderately flexible blades and second using a multibody based large-deformation analysis (especially applicable for extremely flexible blades) incorporating a geometrically exact beam model. An unsteady aerodynamic model is included in the analysis with two different inflow models, single streamtube and a double-multiple streamtube inflow model. For the cycloidal rotors using moderate

Moble, Benedict

352

Rotor hover performance and system design of an efficient coaxial rotary wing micro air vehicle  

NASA Astrophysics Data System (ADS)

Rotary-wing Micro air vehicles (MAVs) due to their unique hovering and low-speed flight capabilities are specially suited for missions that require operation in constrained spaces. Size restrictions force MAVs to operate in a low Reynolds number aerodynamic regime where viscous effects are dominant. This results in poor aerodynamic performance of conventional airfoils and rotor configurations. This dissertation explores the design issues that affect the hover performance of small-scale rotors and the implementation of a working coaxial MAV prototype. A computerized hover test stand was used for the systematic testing of single and coaxial small-scale rotors. Thin circular arcs were chosen for blade manufacturing because of their good aerodynamic characteristics at low Reynolds numbers, and simplified parameterization. Influence of airfoil geometry on single rotor hover performance was studied on untwisted rectangular blades. Non rectangular blades were used to study coupled airfoil and blade parameters. Tip tapered geometries were manufactured by removing material from baseline rectangular blades producing a coupling between blade planform, twist distribution, and spanwise airfoil shape. Performance gains were obtained by introducing large negative twist angles over short radial distances at the blade tips. A parametric study of the blade geometries resulted in maximum figures of merit of 0.65. Coaxial rotor performance at torque equilibrium was explored for different trims and operating conditions. It was found that the upper rotor was marginally affected by the lower one at spacings larger than 35% of the rotor radius, and that it produced about 60% of the total thrust. Experiments showed that power loading was maximized when higher collectives were used at the lower rotor, resulting in sizable differences in rotational speed between rotors. The CFD solver INS2d was used for a two-dimensional parametric aerodynamic study of circular arc airfoils. Lift, drag, and moment coefficients were explored over a range of Reynolds numbers. Validation with wind-tunnel data showed that lift predictions were satisfactory; however, drag was under-predicted at low angles of attack. The CFD database was integrated to a BEMT rotor model through a parameterization that coupled blade planform with twist distribution and airfoil shape. Thrust and maximum FM predictions were satisfactory for rectangular and non-rectangular blades with maximum cambers of 6% and below. The BEMT model was extended to the coaxial rotor case, producing good thrust and power predictions with errors within 5% of the experimental measurements. The approach validated the use of analytical and numerical tools commonly used in full-scale analysis, and proved to be a versatile system design tool. A fully functional coaxial MAV was developed based on the aerodynamic studies performed. Transmission, rotors, and swashplate were designed from scratch. Batteries, motors, and electronics were carefully selected off-the-shelf components. The prototype has been used as a testing platform for control systems and algorithms.

Bohorquez, Felipe

2007-12-01

353

Maglev vehicles and superconductor technology: Integration of high-speed ground transportation into the air travel system  

SciTech Connect

This study was undertaken to (1) evaluate the potential contribution of high-temperature superconductors (HTSCs) to the technical and economic feasibility of magnetically levitated (maglev) vehicles, (2) determine the status of maglev transportation research in the United States and abroad, (3) identify the likelihood of a significant transportation market for high-speed maglev vehicles, and (4) provide a preliminary assessment of the potential energy and economic benefits of maglev systems. HTSCs should be considered as an enhancing, rather than an enabling, development for maglev transportation because they should improve reliability and reduce energy and maintenance costs. Superconducting maglev transportation technologies were developed in the United States in the late 1960s and early 1970s. Federal support was withdrawn in 1975, but major maglev transportation programs were continued in Japan and West Germany, where full-scale prototypes now carry passengers at speeds of 250 mi/h in demonstration runs. Maglev systems are generally viewed as very-high-speed train systems, but this study shows that the potential market for maglev technology as a train system, e.g., from one downtown to another, is limited. Rather, aircraft and maglev vehicles should be seen as complementing rather than competing transportation systems. If maglev systems were integrated into major hub airport operations, they could become economical in many relatively high-density US corridors. Air traffic congestion and associated noise and pollutant emissions around airports would also be reduced. 68 refs., 26 figs., 16 tabs.

Johnson, L.R.; Rote, D.M.; Hull, J.R.; Coffey, H.T.; Daley, J.G.; Giese, R.F.

1989-04-01

354

Variable Speed CMG Control of a Dual-Spin Stabilized Unconventional VTOL Air Vehicle  

NASA Technical Reports Server (NTRS)

This paper describes an approach based on using both bias momentum and multiple control moment gyros for controlling the attitude of statically unstable thrust-levitated vehicles in hover or slow translation. The stabilization approach described in this paper uses these internal angular momentum transfer devices for stability, augmented by thrust vectoring for trim and other outer loop control functions, including CMG stabilization/ desaturation under persistent external disturbances. Simulation results show the feasibility of (1) improved vehicle performance beyond bias momentum assisted vector thrusting control, and (2) using control moment gyros to significantly reduce the external torque required from the vector thrusting machinery.

Lim, Kyong B.; Moerder, Daniel D.; Shin, J-Y.

2004-01-01

355

Dynamic Network Flow Optimization Models for Air Vehicle Resource Allocation Kendall E. Nygard, Professor  

E-print Network

Institute of Technology (AFIT/ENG) Wright-Patterson AFB, OH 45433 Abstract A weapon system consisting 58105-5164 Phillip R. Chandler Flight Control Division Air Force Research Lab (AFRL/VACA) Wright-Patterson AFB, OH 45433-7531 Meir Pachter, Professor Department of Electrical and Computer Engineering Air Force

Nygard, Kendall E.

356

Vision-Based Control of MicroAirVehicles: Progress and Problems In Estimation  

E-print Network

, feature point tracking, image registra- tion, segmentation, object detection and object identification to this overall objective. I. INTRODUCTION The vital and increasing role of unmanned autonomous vehicles (UAVs" UAVs are emerging in numerous applications of interest to the military. Fixed wing micro

DeVore, Ronald

357

Obstacle avoidance for unmanned air vehicles using optical flow probability distributions  

Microsoft Academic Search

In order for an unmanned aerial vehicle (UAV) to safely fly close to the ground, it must be capable of detecting and avoiding obstacles in its flight path. From a single camera on the UAV, the 3D structure of its surrounding environment, including any obstacles, can be estimated from motion parallax using a technique called structure from motion. Most structure

Paul C. Merrell; Dah-Jye Lee; Randal W. Beard

2004-01-01

358

Obstacle Avoidance for Unmanned Air Vehicles Using Optical Flow Probability Distributions  

Microsoft Academic Search

In order for an unmanned aerial vehicle (UAV) to safely fly close to the ground, it must be capable of detecting and avoiding obstacles in its flight path. From a single camera on the UAV, the 3D structure of its surrounding environment, including any obstacles, can be estimated from motion parallax using a technique called structure from motion. Most structure

Paul Merrell; Dah-Jye Lee; Randal Beard

2004-01-01

359

ANALYSIS OF MOTOR VEHICLE EMISSIONS IN A HOUSTON TUNNEL DURING THE TEXAS AIR QUALITY STUDY 2000  

EPA Science Inventory

Measurements from a Houston tunnel were used to develop fuel consumption based emission factors for CO, NOx, and Non-Methane Organic Compound (NMOC) for on-road gasoline vehicles. The Houston NOx emission factor was at the low range of emission factors reported in previous (pr...

360

Coordinated sea rescue system based on unmanned air vehicles and surface vessels  

Microsoft Academic Search

This paper presents a sea rescue system based on a coordinated team of a sensing\\/monitoring Unmanned Aerial Vehicle (UAV) and a rescuing Unmanned Surface Vessel (USV) that exploits the measurements provided by the UAV to estimate the castaways position. The system models the castaway location evolution using an Artificial Neural Network (ANN) that is trained before the rescue starts using

Francisco Fernandez Ramirez; David Sanchez Benitez; Eva Besada Portas; Jose A. Lopez Orozco

2011-01-01

361

The impact of plug-in vehicles on greenhouse gas and criteria pollutants emissions in an urban air shed using a spatially and temporally resolved dispatch model  

Microsoft Academic Search

With the introduction of plug-in vehicles (PEVs) into the light-duty vehicle fleet, the tail-pipe emissions of GHGs and criteria pollutants will be partly transferred to electricity generating units. To study the impact of PEVs on well-to-wheels emissions, the U.S. Western electrical grid serving the South Coast Air Basin (SoCAB) of California is modeled with both spatial and temporal resolution at

Ghazal Razeghi; Tim Brown; G. Scott Samuelsen

2011-01-01

362

Testing of aircraft passenger seat cushion materials. Full scale, test description and results, volume 1  

NASA Technical Reports Server (NTRS)

Eight different seat cushion configurations were subjected to full-scale burn tests. Each cushion configuration was tested twice for a total of sixteen tests. Two different fire sources were used. They consisted of one liter of Jet A fuel for eight tests and a radiant energy source with propane flame for eight tests. Both fire sources were ignited by a propane flame. During each test, data were recorded for smoke density, cushion temperatures, radiant heat flux, animal response to combustion products, rate of weight loss of test specimens, cabin temperature, and for the type and content of gas within the cabin atmosphere. When compared to existing passenger aircraft seat cushions, the test specimens incorporating a fire barrier and those fabricated from advanced materials, using improved construction methods, exhibited significantly greater fire resistance.

Schutter, K. J.; Gaume, J. G.; Duskin, F. E.

1981-01-01

363

Some factors affecting the use of lighter than air systems. [economic and performance estimates for dirigibles and semi-buoyant hybrid vehicles  

NASA Technical Reports Server (NTRS)

The uses of lighter-than-air vehicles are examined in the present day transportation environment. Conventional dirigibles were found to indicate an undesirable economic risk due to their low speeds and to uncertainties concerning their operational use. Semi-buoyant hybrid vehicles are suggested as an alternative which does not have many of the inferior characteristics of conventional dirigibles. Economic and performance estimates for hybrid vehicles indicate that they are competitive with other transportation systems in many applications, and unique in their ability to perform some highly desirable emergency missions.

Havill, C. D.

1974-01-01

364

77 FR 1892 - Approval and Promulgation of Air Quality Implementation Plans; State of Colorado; Motor Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...submitting comments. Email: russo.rebecca@epa.gov. Mail: Carl Daly, Director...holidays. FOR FURTHER INFORMATION CONTACT: Rebecca Russo, Air Program, Mailcode 8P-AR...303) 312-6064, or email russo.rebecca@epa.gov. SUPPLEMENTARY...

2012-01-12

365

Assessment of the capacity of vehicle cabin air inlet filters to reduce diesel exhaust-induced symptoms in human volunteers  

PubMed Central

Background Exposure to particulate matter (PM) air pollution especially derived from traffic is associated with increases in cardiorespiratory morbidity and mortality. In this study, we evaluated the ability of novel vehicle cabin air inlet filters to reduce diesel exhaust (DE)-induced symptoms and markers of inflammation in human subjects. Methods Thirty healthy subjects participated in a randomized double-blind controlled crossover study where they were exposed to filtered air, unfiltered DE and DE filtered through two selected particle filters, one with and one without active charcoal. Exposures lasted for one hour. Symptoms were assessed before and during exposures and lung function was measured before and after each exposure, with inflammation assessed in peripheral blood five hours after exposures. In parallel, PM were collected from unfiltered and filtered DE and assessed for their capacity to drive damaging oxidation reactions in a cell-free model, or promote inflammation in A549 cells. Results The standard particle filter employed in this study reduced PM10 mass concentrations within the exposure chamber by 46%, further reduced to 74% by the inclusion of an active charcoal component. In addition use of the active charcoal filter was associated by a 75% and 50% reduction in NO2 and hydrocarbon concentrations, respectively. As expected, subjects reported more subjective symptoms after exposure to unfiltered DE compared to filtered air, which was significantly reduced by the filter with an active charcoal component. There were no significant changes in lung function after exposures. Similarly diesel exhaust did not elicit significant increases in any of the inflammatory markers examined in the peripheral blood samples 5 hour post-exposure. Whilst the filters reduced chamber particle concentrations, the oxidative activity of the particles themselves, did not change following filtration with either filter. In contrast, diesel exhaust PM passed through the active charcoal combination filter appeared less inflammatory to A549 cells. Conclusions A cabin air inlet particle filter including an active charcoal component was highly effective in reducing both DE particulate and gaseous components, with reduced exhaust-induced symptoms in healthy volunteers. These data demonstrate the effectiveness of cabin filters to protect subjects travelling in vehicles from diesel exhaust emissions. PMID:24621126

2014-01-01

366

A Feasibility Study on the Control of a Generic Air Vehicle Using Control Moment Gyros  

NASA Technical Reports Server (NTRS)

This paper examines feasibility and performance issues in using Control Moment Gyroscopes (CMGs) to control the attitude of a fixed-wing aircraft. The paper describes a control system structure that permits allocating control authority and bandwidth between a CMG system and conventional aerodynamic control surfaces to stabilize a vehicle with neutral aerodynamic stability. A simulation study explores the interplay between aerodynamic and CMG effects, and indicates desirable physical characteristics for a CMG system to be used for aircraft attitude control.

Lim, Kyong B.; Moerder, Daniel D.

2006-01-01

367

Net air emissions from electric vehicles: the effect of carbon price and charging strategies.  

PubMed

Plug-in hybrid electric vehicles (PHEVs) may become part of the transportation fleet on time scales of a decade or two. We calculate the electric grid load increase and emissions due to vehicle battery charging in PJM and NYISO with the current generation mix, the current mix with a $50/tonne CO(2) price, and this case but with existing coal generators retrofitted with 80% CO(2) capture. We also examine all new generation being natural gas or wind+gas. PHEV fleet percentages between 0.4 and 50% are examined. Vehicles with small (4 kWh) and large (16 kWh) batteries are modeled with driving patterns from the National Household Transportation Survey. Three charging strategies and three scenarios for future electric generation are considered. When compared to 2020 CAFE standards, net CO(2) emissions in New York are reduced by switching from gasoline to electricity; coal-heavy PJM shows somewhat smaller benefits unless coal units are fitted with CCS or replaced with lower CO(2) generation. NO(X) is reduced in both RTOs, but there is upward pressure on SO(2) emissions or allowance prices under a cap. PMID:21309508

Peterson, Scott B; Whitacre, J F; Apt, Jay

2011-03-01

368

Composed cushions and coexistence with neighbouring species promoting the persistence of Eritrichium nanum in high alpine vegetation  

Microsoft Academic Search

.  Zoller H. and Lenzin H. 2006. Composed cushions and coexistence with neighbouring species promoting the persistence of Eritrichium nanum in high alpine vegetation. Bot. Helv. 116: 31–40.\\u000a \\u000a Cushions of high alpine plants may consist of several individuals, either of the same or of different species (composed cushions).\\u000a To clarify the role of this coexistence for the life history of alpine

Heinrich Zoller; Heiner Lenzin

2006-01-01

369

Experimental Investigation of Project Orion Crew Exploration Vehicle Aeroheating: LaRC 20-Inch Mach 6 Air Tunnel Test 6931  

NASA Technical Reports Server (NTRS)

An investigation of the aeroheating environment of the Project Orion Crew Entry Vehicle has been performed in the Langley Research Center 20-Inch Mach 6 Air Tunnel. Data were measured on a approx.3.5% scale model (0.1778-m/7-inch diameter) of the vehicle using coaxial thermocouples at free stream Reynolds numbers of 2.0 10(exp 6)/ft to 7.30 10(exp 6)/ft and computational predictions were generated for all test conditions. The primary goals of this test were to obtain convective heating data for use in assessing the accuracy of the computational technique and to validate test methodology and heating data from a test of the same wind tunnel model in the Arnold Engineering Development Center Tunnel 9. Secondary goals were to determine the extent of transitional/turbulent data which could be produced on a CEV model in this facility, either with or without boundary-layer trips, and to demonstrate continuous pitch-sweep operation in this tunnel for heat transfer testing.

Hollis, Brian R.

2009-01-01

370

Prediction of thermal behaviors of an air-cooled lithium-ion battery system for hybrid electric vehicles  

NASA Astrophysics Data System (ADS)

Thermal management has been one of the major issues in developing a lithium-ion (Li-ion) hybrid electric vehicle (HEV) battery system since the Li-ion battery is vulnerable to excessive heat load under abnormal or severe operational conditions. In this work, in order to design a suitable thermal management system, a simple modeling methodology describing thermal behavior of an air-cooled Li-ion battery system was proposed from vehicle components designer's point of view. A proposed mathematical model was constructed based on the battery's electrical and mechanical properties. Also, validation test results for the Li-ion battery system were presented. A pulse current duty and an adjusted US06 current cycle for a two-mode HEV system were used to validate the accuracy of the model prediction. Results showed that the present model can give good estimations for simulating convective heat transfer cooling during battery operation. The developed thermal model is useful in structuring the flow system and determining the appropriate cooling capacity for a specified design prerequisite of the battery system.

Choi, Yong Seok; Kang, Dal Mo

2014-12-01

371

A Common Communications, Navigation and Surveillance Infrastructure for Accommodating Space Vehicles in the Next Generation Air Transportation System  

NASA Technical Reports Server (NTRS)

Suborbital space flight and space tourism are new potential markets that could significantly impact the National Airspace System (NAS). Numerous private companies are developing space flight capabilities to capture a piece of an emerging commercial space transportation market. These entrepreneurs share a common vision that sees commercial space flight as a profitable venture. Additionally, U.S. space exploration policy and national defense will impose significant additional demands on the NAS. Air traffic service providers must allow all users fair access to limited airspace, while ensuring that the highest levels of safety, security, and efficiency are maintained. The FAA's Next Generation Air Transportation System (NextGen) will need to accommodate spacecraft transitioning to and from space through the NAS. To accomplish this, space and air traffic operations will need to be seamlessly integrated under some common communications, navigation and surveillance (CNS) infrastructure. As part of NextGen, the FAA has been developing the Automatic Dependent Surveillance Broadcast (ADS-B) which utilizes the Global Positioning System (GPS) to track and separate aircraft. Another key component of NextGen, System-Wide Information Management/ Network Enabled Operations (SWIM/NEO), is an open architecture network that will provide NAS data to various customers, system tools and applications. NASA and DoD are currently developing a space-based range (SBR) concept that also utilizes GPS, communications satellites and other CNS assets. The future SBR will have very similar utility for space operations as ADS-B and SWIM has for air traffic. Perhaps the FAA, NASA, and DoD should consider developing a common space-based CNS infrastructure to support both aviation and space transportation operations. This paper suggests specific areas of research for developing a CNS infrastructure that can accommodate spacecraft and other new types of vehicles as an integrated part of NextGen.

VanSuetendael, RIchard; Hayes, Alan; Birr, Richard

2008-01-01

372

White, J. L., Ruddle, R. A., Howes, A., Snowden, R. J., Savage, J. C., & Jones, D. M. (2001). Eyes in the sky: Human factors and uninhabited air vehicles. Journal of Defence Science, 6, 88-94.  

E-print Network

distributions and environmental occlusion. All of the investigations were performed using a UAV simulator). Eyes in the sky: Human factors and uninhabited air vehicles. Journal of Defence Science, 6, 88-94. Eyes in the Sky: Human Factors and Uninhabited Air Vehicles Roy Ruddle, Andrew Howes, Robert Snowden, Justin

Berzins, M.

2001-01-01

373

78 FR 24373 - Approval and Promulgation of Air Quality Implementation Plans; Wisconsin; Amendments to Vehicle...  

Federal Register 2010, 2011, 2012, 2013, 2014

...annually to reflect the change in the Consumer Price Index (CPI) as compared to the CPI...demonstration. Table 3--(SIP I/M Program vs. Current I/M Program...interfered with attainment of other air quality standards. Southeast Wisconsin is...

2013-04-25

374

Nonlinear air-to-fuel ratio and engine speed control for hybrid vehicles  

Microsoft Academic Search

Internal combustion spark ignition engine management systems regulate the fuel, spark, and idle air subsystems to achieve sufficient engine performance at acceptable fuel economy and tailpipe emission levels. Engine control units also monitor other engine processes, using a suite of sensors, and periodically check the system actuators' operation to satisfy legislated onboard diagnostics. The majority of production engines regulate the

John R. Wagner; Darren M. Dawson; Liu Zeyu

2003-01-01

375

The best for the guest: high Andean nurse cushions of Azorella madreporica enhance arbuscular mycorrhizal status in associated plant species.  

PubMed

Positive interactions between cushion plant and associated plants species in the high Andes of central Chile should also include the effects of fungal root symbionts. We hypothesized that higher colonization by arbuscular mycorrhizal (AM) fungi exists in cushion-associated (nursling) plants compared with conspecific individuals growing on bare ground. We assessed the AM status of Andean plants at two sites at different altitudes (3,200 and 3,600 ma.s.l.) in 23 species, particularly in cushions of Azorella madreporica and five associated plants; additionally, AM fungal spores were retrieved from soil outside and beneath cushions. 18 of the 23 examined plant species presented diagnostic structures of arbuscular mycorrhiza; most of them were also colonized by dark-septate endophytes. Mycorrhization of A. madreporica cushions showed differences between both sites (68% and 32%, respectively). In the native species Hordeum comosum, Nastanthus agglomeratus, and Phacelia secunda associated to A. madreporica, mycorrhization was six times higher than in the same species growing dispersed on bare ground at 3,600 ma.s.l., but mycorrhiza development was less cushion dependent in the alien plants Cerastium arvense and Taraxacum officinale at both sites. The ratio of AM fungal spores beneath versus outside cushions was also 6:1. The common and abundant presence of AM in cushion communities at high altitudes emphasizes the importance of the fungal root symbionts in such situations where plant species benefit from the microclimatic conditions generated by the cushion and also from well-developed mycorrhizal networks. PMID:21384201

Casanova-Katny, M Angélica; Torres-Mellado, Gustavo Adolfo; Palfner, Goetz; Cavieres, Lohengrin A

2011-10-01

376

Air-ground vehicle detection with a reduced object category specific visual dictionary  

NASA Astrophysics Data System (ADS)

Nowadays ground vehicle detection on airborne platforms is becoming very important for intelligent visual surveillance applications. Object detection using cascade structured classifiers is booming fast in recent decade, and very successful in real-time applications. However, most of them apply a sliding window on multi-scaled images which commonly need heavy computational expense, therefore, are only suitable for using simple features. In this paper, a biologically inspired object detection algorithm is proposed, which exploits image patch based feature learning and visual saliency detection. The image patch based local features are learnt by unsupervised learning to generate an object category specific visual dictionary. Visual saliency detection is performed to extract candidate object regions from a whole image using the learnt local features. Instead of a sliding window, a candidate object region is sent to an object classifier only when its features are salient on the whole image. Since the number of candidate object regions decreases dramatically, it allows to utilize much complex features to represent object images so that it can increase the descriptive capability of the learnt features. The experimental results on practical vehicle image datasets indicate that less computational expense and good detection performance can be achieved.

Jin, Lizuo; Dong, Yanchao; Xu, Qinghan; Jie, Feiran

2013-10-01

377

Trends in on-road vehicle emissions and ambient air quality in Atlanta, Georgia, USA, from the late 1990s through 2009  

PubMed Central

On-road vehicle emissions of carbon monoxide (CO), nitrogen oxides (NOx), and volatile organic compounds (VOCs) during 1995–2009 in the Atlanta Metropolitan Statistical Area were estimated using the Motor Vehicle Emission Simulator (MOVES) model and data from the National Emissions Inventories and the State of Georgia. Statistically significant downward trends (computed using the nonparametric Theil-Sen method) in annual on-road CO, NOx, and VOC emissions of 6.1%, 3.3%, and 6.0% per year, respectively, are noted during the 1995–2009 period despite an increase in total vehicle distance traveled. The CO and NOx emission trends are correlated with statistically significant downward trends in ambient air concentrations of CO and NOx in Atlanta ranging from 8.0% to 11.8% per year and from 5.8% to 8.7% per year, respectively, during similar time periods. Weather-adjusted summertime ozone concentrations in Atlanta exhibited a statistically significant declining trend of 2.3% per year during 2001– 2009. Although this trend coexists with the declining trends in on-road NOx, VOC, and CO emissions, identifying the cause of the downward trend in ozone is complicated by reductions in multiple precursors from different source sectors. Implications: Large reductions in on-road vehicle emissions of CO and NOx in Atlanta from the late 1990s to 2009, despite an increase in total vehicle distance traveled, contributed to a significant improvement in air quality through decreases in ambient air concentrations of CO and NOx during this time period. Emissions reductions in motor vehicles and other source sectors resulted in these improvements and the observed declining trend in ozone concentrations over the past decade. Although these historical trends cannot be extrapolated to the future because pollutant concentration contributions due to on-road vehicle emissions will likely become an increasingly smaller fraction of the atmospheric total, they provide an indication of the benefits of past control measures. PMID:25122954

Vijayaraghavan, Krish; DenBleyker, Allison; Ma, Lan; Lindhjem, Chris; Yarwood, Greg

2014-01-01

378

Implementation of the Rauch-Tung-Striebel Smoother for Sensor Compatibility Correction of a Fixed-Wing Unmanned Air Vehicle  

PubMed Central

This paper presents a complete procedure for sensor compatibility correction of a fixed-wing Unmanned Air Vehicle (UAV). The sensors consist of a differential air pressure transducer for airspeed measurement, two airdata vanes installed on an airdata probe for angle of attack (AoA) and angle of sideslip (AoS) measurement, and an Attitude and Heading Reference System (AHRS) that provides attitude angles, angular rates, and acceleration. The procedure is mainly based on a two pass algorithm called the Rauch-Tung-Striebel (RTS) smoother, which consists of a forward pass Extended Kalman Filter (EKF) and a backward recursion smoother. On top of that, this paper proposes the implementation of the Wiener Type Filter prior to the RTS in order to avoid the complicated process noise covariance matrix estimation. Furthermore, an easy to implement airdata measurement noise variance estimation method is introduced. The method estimates the airdata and subsequently the noise variances using the ground speed and ascent rate provided by the Global Positioning System (GPS). It incorporates the idea of data regionality by assuming that some sort of statistical relation exists between nearby data points. Root mean square deviation (RMSD) is being employed to justify the sensor compatibility. The result shows that the presented procedure is easy to implement and it improves the UAV sensor data compatibility significantly. PMID:22163819

Chan, Woei-Leong; Hsiao, Fei-Bin

2011-01-01

379

Impact of electric vehicles on select air pollutants: A comprehensive model  

SciTech Connect

The modeling methodology and sample results of a comprehensive investigation into the impact of electric vehicles (EVs) on the Maricopa County Non-Attainment Area is given. The proposed model includes submodels of power plants using simulation techniques to produce unit commitment schedules. Scenario analysis was employed to address the inherent uncertainty involved in modeling rapidly changing technology. Two well-articulated scenarios postulated EV penetration rates, performance characteristics and load requirements. The proposed model provides estimates of the change in pollutant levels. The pollutants examined in this research are: hydrocarbons, carbon monoxide, carbon dioxide, nitrogen dioxide, sulfur dioxide, and particulate matter under 10 microns. The value of the research described here lies in the comprehensiveness of the model and the depiction of the sensitivity of the conclusions to the altering of the value of the model inputs.

DeKoster, D.R. [COBE Cardiovascular Inc., Arvada, CO (United States)] [COBE Cardiovascular Inc., Arvada, CO (United States); Morrow, K.P. [Salt River Project, Phoenix, AZ (United States)] [Salt River Project, Phoenix, AZ (United States); Schaub, D.A. [Univ. of Florida, Gainesville, FL (United States)] [Univ. of Florida, Gainesville, FL (United States); Hubele, N.F. [Arizona State Univ., Tempe, AZ (United States)] [Arizona State Univ., Tempe, AZ (United States)

1995-08-01

380

Air pollutant emissions from on-road vehicles in China, 1999-2011.  

PubMed

The on-road vehicular emission in China from 1999 to 2011 was estimated, based on the emission factors of vehicles with different emission standards calculated by the COPERT model. The CO, NMVOC, NOX, BC and OC emissions changed from 19.7 Tg, 4.4 Tg, 2.3 Tg, 47.1 Gg and 74.4 Gg in 1999 to 32.7 Tg, 4.1 Tg, 7.6 Tg, 177.6 Gg and 101.5 Gg in 2011, respectively. The general trend for CO, NOX and BC was increasing, while the tendency for NMVOC and OC was firstly increase before 2002 and then decrease from 2003. The spatial analysis results showed that high emissions occurred in developed provinces (Guangdong, Shandong, Hebei, Jiangsu and Henan). The correlation between vehicular emissions and GDP were further investigated and good linear correlation was found. The not-obvious change of the inter-annual (1999-2011) fitted straight line slope and the sustained increasing emissions for NOX and BC suggested that the challenge of mitigating vehicular NOX and BC emissions is severe in China. The contribution from different vehicle types was also analyzed. Passenger car (PC) and motorcycle (MC) was the main contributor to the CO and NMVOC emissions. However, the contribution ratio of MC was decreasing from 36.6% and 68.8% in 1999 to 15.7% and 25.7% in 2011. Heavy duty truck (HDT) was the dominant contributor to NOX, BC and OC, with proportions of 58.9%, 57.6% and 52.8% in 2011, respectively. In addition, the uncertainty of the estimated emissions was also assessed based on the Monte Carlo simulation. PMID:25051424

Lang, Jianlei; Cheng, Shuiyuan; Zhou, Ying; Zhang, Yonglin; Wang, Gang

2014-10-15

381

Design and development of an unconventional VTOL micro air vehicle: The Cyclocopter  

NASA Astrophysics Data System (ADS)

This paper discusses the systematic experimental and vehicle design/development studies conducted at the University of Maryland which culminated in the development of the first flying Cyclocopter in the history. Cyclocopter is a novel Vertical Take-Off and Landing (VTOL) aircraft, which utilizes cycloidalrotors (cyclorotors), a revolutionary horizontal axis propulsion concept, that has many advantages such as higher aerodynamic efficiency, maneuverability and high-speed forward flight capability when compared to a conventional helicopter rotor. The experimental studies included a detailed parametric study to understand the effect of rotor geometry and blade kinematics on cyclorotor hover performance. Based on the experimental results, higher blade pitch angles were found to improve thrust and increase the power loading (thrust per unit power) of the cyclorotor. Asymmetric pitching with higher pitch angle at the top than at the bottom produced better power loading. The chordwise optimum pitching axis location was observed to be around 25-35% of the blade chord. Because of the flow curvature effects, the cycloidal rotor performance was a strong function of the chord/radius ratio. The optimum chord/radius ratios were extremely high, around 0.5-0.8, depending on the blade pitching amplitude. A flow field investigation was also conducted using Particle Image Velocimetry (PIV) to unravel the physics behind thrust production of a cyclorotor. PIV studies indicated evidence of a stall delay as well as possible increases in lift on the blades from the presence of a leading edge vortex. The goal of all these studies was to understand and optimize the performance of a micro-scale cyclorotor so that it could be used in a flying vehicle. An optimized cyclorotor was used to develop a 200 gram cyclocopter capable of autonomous stable hover using an onboard feedback controller.

Benedict, Moble; Chopra, Inderjit

2012-06-01

382

Application of a high-efficiency cabin air filter for simultaneous mitigation of ultrafine particle and carbon dioxide exposures inside passenger vehicles.  

PubMed

Modern passenger vehicles are commonly equipped with cabin air filters but their filtration efficiency for ultrafine particle (UFP) is rather low. Although setting the vehicle ventilation system to recirculation (RC) mode can reduce in-cabin UFPs by ? 90%, passenger-exhaled carbon dioxide (CO2) can quickly accumulate inside the cabin. Using outdoor air (OA) mode instead can provide sufficient air exchange to prevent CO2 buildup, but in-cabin UFP concentrations would increase. To overcome this dilemma, we developed a simultaneous mitigation method for UFP and CO2 using high-efficiency cabin air (HECA) filtration in OA mode. Concentrations of UFP and other air pollutants were simultaneously monitored in and out of 12 different vehicles under 3 driving conditions: stationary, on local roadways, and on freeways. Under each experimental condition, data were collected with no filter, in-use original equipment manufacturer (OEM) filter, and two types of HECA filters. The HECA filters offered an average in-cabin UFP reduction of 93%, much higher than the OEM filters (? 50% on average). Throughout the measurements, the in-cabin CO2 concentration remained in the range of 620-930 ppm, significantly lower than the typical level of 2500-4000 ppm observed in the RC mode. PMID:24471775

Lee, Eon S; Zhu, Yifang

2014-02-18

383

A multimodal micro air vehicle for autonomous flight in near-earth environments  

NASA Astrophysics Data System (ADS)

Reconnaissance, surveillance, and search-and-rescue missions in near-Earth environments such as caves, forests, and urban areas pose many new challenges to command and control (C2) teams. Of great significance is how to acquire situational awareness when access to the scene is blocked by enemy fire, rubble, or other occlusions. Small bird-sized aerial robots are expendable and can fly over obstacles and through small openings to assist in the acquisition and distribution of intelligence. However, limited flying space and densely populated obstacle fields requires a vehicle that is capable of hovering, but also maneuverable. A secondary flight mode was incorporated into a fixed-wing aircraft to preserve its maneuverability while adding the capability of hovering. An inertial measurement sensor and onboard flight control system were interfaced and used to transition the hybrid prototype from cruise to hover flight and sustain a hover autonomously. Furthermore, the hovering flight mode can be used to maneuver the aircraft through small openings such as doorways. An ultrasonic and infrared sensor suite was designed to follow exterior building walls until an ingress route was detected. Reactive control was then used to traverse the doorway and gather reconnaissance. Entering a dangerous environment to gather intelligence autonomously will provide an invaluable resource to any C2 team. The holistic approach of platform development, sensor suite design, and control serves as the philosophy of this work.

Green, William Edward

384

Inertial attitude control of a bat-like morphing-wing air vehicle.  

PubMed

This paper presents a novel bat-like unmanned aerial vehicle inspired by the morphing-wing mechanism of bats. The goal of this paper is twofold. Firstly, a modelling framework is introduced for analysing how the robot should manoeuvre by means of changing wing morphology. This allows the definition of requirements for achieving forward and turning flight according to the kinematics of the wing modulation. Secondly, an attitude controller named backstepping+DAF is proposed. Motivated by biological evidence about the influence of wing inertia on the production of body accelerations, the attitude control law incorporates wing inertia information to produce desired roll (?) and pitch (?) acceleration commands (desired angular acceleration function (DAF)). This novel control approach is aimed at incrementing net body forces (F(net)) that generate propulsion. Simulations and wind-tunnel experimental results have shown an increase of about 23% in net body force production during the wingbeat cycle when the wings are modulated using the DAF as a part of the backstepping control law. Results also confirm accurate attitude tracking in spite of high external disturbances generated by aerodynamic loads at airspeeds up to 5 ms?¹. PMID:23211685

Colorado, J; Barrientos, A; Rossi, C; Parra, C

2013-03-01

385

Verification and Tuning of an Adaptive Controller for an Unmanned Air Vehicle  

NASA Technical Reports Server (NTRS)

This paper focuses on the analysis and tuning of a controller based on the Adaptive Control Technology for Safe Flight (ACTS) architecture. The ACTS architecture consists of a nominal, non-adaptive controller that provides satisfactory performance under nominal flying conditions, and an adaptive controller that provides robustness under off-nominal ones. A framework unifying control verification and gain tuning is used to make the controller s ability to satisfy the closed-loop requirements more robust to uncertainty. In this paper we tune the gains of both controllers using this approach. Some advantages and drawbacks of adaptation are identified by performing a global robustness assessment of both the adaptive controller and its non-adaptive counterpart. The analyses used to determine these characteristics are based on evaluating the degradation in closed-loop performance resulting from uncertainties having increasing levels of severity. The specific adverse conditions considered can be grouped into three categories: aerodynamic uncertainties, structural damage, and actuator failures. These failures include partial and total loss of control effectiveness, locked-in-place control surface deflections, and engine out conditions. The requirements considered are the peak structural loading, the ability of the controller to track pilot commands, the ability of the controller to keep the aircraft s state within the reliable flight envelope, and the handling/riding qualities of the aircraft. The nominal controller resulting from these tuning strategies was successfully validated using the NASA GTM Flight Test Vehicle.

Crespo, Luis G.; Matsutani, Megumi; Annaswamy, Anuradha M.

2010-01-01

386

Water cooling system for an air-breathing hypersonic test vehicle  

NASA Technical Reports Server (NTRS)

This study provides concepts for hypersonic experimental scramjet test vehicles which have low cost and low risk. Cryogenic hydrogen is used as the fuel and coolant. Secondary water cooling systems were designed. Three concepts are shown: an all hydrogen cooling system, a secondary open loop water cooled system, and a secondary closed loop water cooled system. The open loop concept uses high pressure helium (15,000 psi) to drive water through the cooling system while maintaining the pressure in the water tank. The water flows through the turbine side of the turbopump to pump hydrogen fuel. The water is then allowed to vent. In the closed loop concept high pressure, room temperature, compressed liquid water is circulated. In flight water pressure is limited to 6000 psi by venting some of the water. Water is circulated through cooling channels via an ejector which uses high pressure gas to drive a water jet. The cooling systems are presented along with finite difference steady-state and transient analysis results. The results from this study indicate that water used as a secondary coolant can be designed to increase experimental test time, produce minimum venting of fluid and reduce overall development cost.

Petley, Dennis H.; Dziedzic, William M.

1993-01-01

387

Size class structure, growth rates, and orientation of the central Andean cushion Azorella compacta  

PubMed Central

Azorella compacta (llareta; Apiaceae) forms dense, woody, cushions and characterizes the high elevation rocky slopes of the central Andean Altiplano. Field studies of an elevational gradient of A. compacta within Lauca National Park in northern Chile found a reverse J-shape distribution of size classes of individuals with abundant small plants at all elevations. A new elevational limit for A. compacta was established at 5,250 m. A series of cushions marked 14 years earlier showed either slight shrinkage or small degrees of growth up to 2.2 cm yr?1. Despite their irregularity in growth, cushions of A. compacta show a strong orientation, centered on a north-facing aspect and angle of about 20° from horizontal. This exposure to maximize solar irradiance closely matches previous observations of a population favoring north-facing slopes at a similar angle. Populations of A. compacta appear to be stable, or even expanding, with young plants abundant. PMID:25802811

Trenary, Tim; Graham, Eric A.; Stenzel, William; Rundel, Philip W.

2015-01-01

388

High resolution modeling of the effects of alternative fuels use on urban air quality: introduction of natural gas vehicles in Barcelona and Madrid Greater Areas (Spain).  

PubMed

The mitigation of the effects of on-road traffic emissions on urban air pollution is currently an environmental challenge. Air quality modeling has become a powerful tool to design environment-related strategies. A wide range of options is being proposed; such as the introduction of natural gas vehicles (NGV), biofuels or hydrogen vehicles. The impacts on air quality of introducing specific NGV fleets in Barcelona and Madrid (Spain) are assessed by means of the WRF-ARW/HERMES/CMAQ modeling system with high spatial-temporal resolution (1 km(2), 1 h). Seven emissions scenarios are defined taking into account the year 2004 vehicle fleet composition of the study areas and groups of vehicles susceptible of change under a realistic perspective. O(3) average concentration rises up to 1.3% in Barcelona and up to 2.5% in Madrid when introducing the emissions scenarios, due to the NO(x) reduction in VOC-controlled areas. Nevertheless, NO(2), PM10 and SO(2) average concentrations decrease, up to 6.1%, 1.5% and 6.6% in Barcelona and up to 20.6%, 8.7% and 14.9% in Madrid, respectively. Concerning SO(2) and PM10 reductions the most effective single scenario is the introduction of 50% of NGV instead of the oldest commercial vehicles; it also reduces NO(2) concentrations in Barcelona, however in Madrid lower levels are attained when substituting 10% of the private cars. This work introduces the WRF-ARW/HERMES/CMAQ modeling system as a useful management tool and proves that the air quality improvement plans must be designed considering the local characteristics. PMID:19022477

Gonçalves, María; Jiménez-Guerrero, Pedro; Baldasano, José M

2009-01-01

389

Aerodynamic characteristics of the ventilated design for flapping wing micro air vehicle.  

PubMed

Inspired by superior flight performance of natural flight masters like birds and insects and based on the ventilating flaps that can be opened and closed by the changing air pressure around the wing, a new flapping wing type has been proposed. It is known that the net lift force generated by a solid wing in a flapping cycle is nearly zero. However, for the case of the ventilated wing, results for the net lift force are positive which is due to the effect created by the "ventilation" in reducing negative lift force during the upstroke. The presence of moving flaps can serve as the variable in which, through careful control of the areas, a correlation with the decrease in negative lift can be generated. The corresponding aerodynamic characteristics have been investigated numerically by using different flapping frequencies and forward flight speeds. PMID:24683339

Zhang, G Q; Yu, S C M

2014-01-01

390

Aerodynamic Characteristics of the Ventilated Design for Flapping Wing Micro Air Vehicle  

PubMed Central

Inspired by superior flight performance of natural flight masters like birds and insects and based on the ventilating flaps that can be opened and closed by the changing air pressure around the wing, a new flapping wing type has been proposed. It is known that the net lift force generated by a solid wing in a flapping cycle is nearly zero. However, for the case of the ventilated wing, results for the net lift force are positive which is due to the effect created by the “ventilation” in reducing negative lift force during the upstroke. The presence of moving flaps can serve as the variable in which, through careful control of the areas, a correlation with the decrease in negative lift can be generated. The corresponding aerodynamic characteristics have been investigated numerically by using different flapping frequencies and forward flight speeds. PMID:24683339

Zhang, G. Q.; Yu, S. C. M.

2014-01-01

391

Association of digital cushion thickness with sole temperature measured with the use of infrared thermography.  

PubMed

The main objective of this study was to investigate the association between digital cushion thickness and sole temperature measured by infrared thermography. Data were collected from 216 lactating Holstein cows at 4 to 10d in milk (DIM). Cows were locomotion scored and sole temperature was measured after claw trimming (a minimum delay of 3 min was allowed for the hoof to cool) using an infrared thermography camera. Temperature was measured at the typical ulcer site of the lateral digit of the left hind foot. Immediately after the thermographic image was obtained, the thickness of the digital cushion was measured by ultrasonography. Rumen fluid samples were collected with a stomach tube and sample pH was measured immediately after collection. Additionally, a blood sample was obtained and used for measurements of serum concentrations of ?-hydroxybutyrate (BHBA), nonesterified fatty acids (NEFA), and haptoglobin. To evaluate the associations of digital cushion thickness with sole temperature, a linear regression model was built using the GLIMMIX procedure in SAS software (SAS Institute Inc., Cary, NC). Sole temperature was the response variable, and digital cushion thickness quartiles, locomotion score group, rumen fluid pH, rumen fluid sample volume, environmental temperature, age in days, and serum levels of NEFA, BHBA, and haptoglobin were fitted in the model. Only significant variables were retained in the final model. Simple linear regression scatter plots were used to illustrate associations between sole temperature (measured by infrared thermography at the typical ulcer site) and environmental temperature and between NEFA and BHBA serum levels and haptoglobin. One-way ANOVA was used to compare rumen fluid pH for different locomotion score groups and for different digital cushion quartiles. Results from the multivariable linear regression model showed that sole temperature increased as locomotion scores increased and decreased as digital cushion thickness increased. These results were adjusted for environmental temperature, which was significantly associated with sole temperature. Serum levels of NEFA, BHBA, and haptoglobin were not associated with sole temperature. However, significant correlations existed between serum levels of NEFA and haptoglobin and between serum levels of BHBA and haptoglobin. Rumen fluid pH was not associated with either locomotion score or digital cushion thickness. In conclusion, we show here that digital cushion thickness was associated with sole temperature in cows at 4 to 10 DIM. PMID:24835964

Oikonomou, G; Trojacanec, P; Ganda, E K; Bicalho, M L S; Bicalho, R C

2014-07-01

392

Effects on Air Pollution and Regional Climate of Producing and Using Hydrogen in Fuel Cells in all U.S. OnroadVehicles  

NASA Astrophysics Data System (ADS)

The purpose of this study was to examine the potential effects on U.S. air pollution and regional climate of switching the current U.S. fleet of onroad motor vehicles to hydrogen fuel-cell vehicles, where hydrogen was produced by (1) steam-reforming of methane, (2) wind energy, or (3) coal gasification. An additional scenario in which the U.S. fleet was switched to gasoline-electric hybrid vehicles was also examined. The model used was GATOR-GCMOM, a global-through-urban-scale nested and parallelized gas, aerosol, transport, radiation, general-circulation, mesoscale, and ocean model. U.S. emission data for the baseline case were obtained from the U.S. National Emission Inventory, which considers 370,000 stack and fugitive sources, 250,000 area sources, and 1700 categories of onroad and nonroad vehicular sources (including motorcycles, passenger vehicles, trucks, recreational vehicles, construction vehicles, farm vehicles, industrial vehicles, etc.). Emission inventories for each of the three hydrogen scenarios were prepared following a process chain analysis that accounted for energy inputs and pollution outputs during all stages of hydrogen and fossil-fuel production, distribution, storage, and end-use. Emitted pollutants accounted for included CO, CO2, H2, H2O, CH4, speciated ROGs, NOx, NH3, SOx, and speciated particulate matter. Results from the first scenario suggest that switching vehicles in the U.S. to hydrogen produced by steam-reforming of methane may reduce emission of NOx, reactive hydrocarbons, CO, CO2, BC, NO3-, and NH4+, but increase CH4, H2, and SO2 (slightly).The switch may also decrease O3 over most of the U.S. but short-term near-surfaces increases may occur over low-vegetated cities (e.g., in Los Angeles and along the Boston-Washington corridor) due to loss of NOx that otherwise titrates O3. The switch is also estimated to decrease PAN, HCHO, and several other pollutants formed in the atmosphere. Isoprene may increase since fewer oxidants (OH, O3) will be available to destroy it. Results for the scenarios involving hydrogen from wind and coal gasification, and from the hybrid scenario will also be discussed, as will regional climate effects (including effects of H2O). Findings to date suggest that, even under a worst-case scenario of 10% hydrogen leakage, the conversion of the current fleet to hydrogen-fuel cell vehicles, where hydrogen is generated by steam-reforming of methane, may result in a measurable improvement in U.S. air quality.

Jacobson, M. Z.; Colella, W. G.; Golden, D. M.

2004-12-01

393

Ethanol and air quality: influence of fuel ethanol content on emissions and fuel economy of flexible fuel vehicles.  

PubMed

Engine-out and tailpipe emissions of NOx, CO, nonmethane hydrocarbons (NMHC), nonmethane organic gases (NMOG), total hydrocarbons (THC), methane, ethene, acetaldehyde, formaldehyde, ethanol, N2O, and NH3 from a 2006 model year Mercury Grand Marquis flexible fuel vehicle (FFV) operating on E0, E10, E20, E30, E40, E55, and E80 on a chassis dynamometer are reported. With increasing ethanol content in the fuel, the tailpipe emissions of ethanol, acetaldehyde, formaldehyde, methane, and ammonia increased; NOx and NMHC decreased; while CO, ethene, and N2O emissions were not discernibly affected. NMOG and THC emissions displayed a pronounced minimum with midlevel (E20-E40) ethanol blends; 25-35% lower than for E0 or E80. Emissions of NOx decreased by approximately 50% as the ethanol content increased from E0 to E30-E40, with no further decrease seen with E55 or E80. We demonstrate that emission trends from FFVs are explained by fuel chemistry and engine calibration effects. Fuel chemistry effects are fundamental in nature; the same trend of increased ethanol, acetaldehyde, formaldehyde, and CH4 emissions and decreased NMHC and benzene emissions are expected for all FFVs. Engine calibration effects are manufacturer and model specific; emission trends for NOx, THC, and NMOG will not be the same for all FFVs. Implications for air quality are discussed. PMID:24328061

Hubbard, Carolyn P; Anderson, James E; Wallington, Timothy J

2014-01-01

394

Design of a High-Altitude Long-Endurance Solar-Powered Unmanned Air Vehicle for Multi-Payload and Operations  

Microsoft Academic Search

Several researches are being carried out at the Politecnico di Torino with the aim of designing a high altitude very-long endurance\\/unmanned air vehicle (HAVE\\/UAV). Being able to fly in the stratosphere (15-20 km) and with an endurance of about 4 months offers an advan- tage and possibility that is presently not available with conventional aircraft or satellites. A computer program

G Romeo; G Frulla; E Cestino

2007-01-01

395

A global meta-analytic contrast of cushion-plant effects on plants and on arthropods  

PubMed Central

Nurse plant facilitation is a commonly reported plant–plant interaction and is an important factor influencing community structure in stressful environments. Cushion plants are an example of alpine nurse plants that modify microclimatic conditions within their canopies to create favourable environments for other plants. In this meta-analysis, the facilitative effects of cushion plants was expanded from previous syntheses of the topic and the relative strength of facilitation for other plants and for arthropods were compared globally.The abundance, diversity, and species presence/absence effect size estimates were tested as plant responses to nurse plants and a composite measure was tested for arthropods. The strength of facilitation was on average three times greater for arthropods relative to all plant responses to cushions. Plant species presence, i.e., frequency of occurrence, was not enhanced by nurse-plants. Cushion plants nonetheless acted as nurse plants for both plants and arthropods in most alpine contexts globally, and although responses by other plant species currently dominate the facilitation literature, preliminary synthesis of the evidence suggests that the potential impacts of nurses may be even greater for other trophic levels. PMID:24688848

Liczner, Amanda R.

2014-01-01

396

Evaluation of on-road vehicle CO and NOx National Emission Inventories using an urban-scale source-oriented air quality model  

NASA Astrophysics Data System (ADS)

The MOBILE6.2 model was replaced by the Motor Vehicle Emission Simulator (MOVES) in 2012 as an official tool recommended by the United States Environmental Protection Agency (US EPA) to predict vehicular pollutant emission factors. In this study, on-road vehicle emission inventories of CO and NOx for Southeast Texas generated by MOVES and MOBILE6.2 in two versions of the 2005 National Emission Inventory (NEI) were studied by comparing predicted CO and NOx using the EPA's Community Multiscale Air Quality (CMAQ) Model incorporated with a source-oriented gas phase chemical mechanism with measurements made at six urban and industrial sites in Southeast Texas. The source tracing technique allows direct determination of contributions of on-road vehicles to overall CO and NOx concentrations and identification of ambient concentration measurements which are mostly impacted by vehicle emissions. By grouping the fractional bias (FB) values of the hourly predictions based on vehicle contributions to total CO or NOx concentrations, clear trends in the FB were observed, indicating systematic biases in the emission inventory for these species. Data points dominated by vehicle emissions suggest that surface CO concentrations due to vehicle exhaust are significantly over-estimated by a factor of 2 using either MOVES or MOBILE6.2. NOx concentrations are overestimated by approximately 20-35% and 70% by using the MOBILE6.2 and MOVES emissions, respectively. Emission scaling runs show that a domain-wide reduction of MOBILE6.2 CO emissions by 60% and NOx emissions by 15-25% leads to better model performance of exhaust CO and NOx concentrations in the current study.

Kota, Sri Harsha; Zhang, Hongliang; Chen, Gang; Schade, Gunnar W.; Ying, Qi

2014-03-01

397

Trends in on-road vehicle emissions and ambient air quality in Atlanta, Georgia, USA, from the late 1990s through 2009.  

PubMed

On-road vehicle emissions of carbon monoxide (CO), nitrogen oxides (NO(x)), and volatile organic compounds (VOCs) during 1995-2009 in the Atlanta Metropolitan Statistical Area were estimated using the Motor Vehicle Emission Simulator (MOVES) model and data from the National Emissions Inventories and the State of Georgia. Statistically significant downward trends (computed using the nonparametric Theil-Sen method) in annual on-road CO, NO(x), and VOC emissions of 6.1%, 3.3%, and 6.0% per year, respectively, are noted during the 1995-2009 period despite an increase in total vehicle distance traveled. The CO and NO(x) emission trends are correlated with statistically significant downward trends in ambient air concentrations of CO and NO(x) in Atlanta ranging from 8.0% to 11.8% per year and from 5.8% to 8.7% per year, respectively, during similar time periods. Weather-adjusted summertime ozone concentrations in Atlanta exhibited a statistically significant declining trend of 2.3% per year during 2001-2009. Although this trend coexists with the declining trends in on-road NO(x), VOC, and CO emissions, identifying the cause of the downward trend in ozone is complicated by reductions in multiple precursors from different source sectors. Implications: Large reductions in on-road vehicle emissions of CO and NO(x) in Atlanta from the late 1990s to 2009, despite an increase in total vehicle distance traveled, contributed to a significant improvement in air quality through decreases in ambient air concentrations of CO and NO(x) during this time period. Emissions reductions in motor vehicles and other source sectors resulted in these improvements and the observed declining trend in ozone concentrations over the past decade. Although these historical trends cannot be extrapolated to the future because pollutant concentration contributions due to on-road vehicle emissions will likely become an increasingly smaller fraction of the atmospheric total, they provide an indication of the benefits of past control measures. PMID:25122954

Vijayaraghavan, Krish; DenBleyker, Allison; Ma, Lan; Lindhjem, Chris; Yarwood, Greg

2014-07-01

398

76 FR 53648 - Federal Motor Vehicle Safety Standards: Occupant Crash Protection  

Federal Register 2010, 2011, 2012, 2013, 2014

...manufacturers to install Lower Anchors and Tethers for Children (LATCH) \\5\\ systems in...comprised of two lower anchorages and one top tether anchorage. Each lower anchorage includes...vehicle seat cushion and seat back. The top tether anchorage is a fixture to which the...

2011-08-29

399

Air toxics exposure from vehicle emissions at a U.S. border crossing: Buffalo Peace Bridge Study.  

PubMed

The Peace Bridge in Buffalo, New York, which spans the Niagara River at the east end of Lake Erie, is one of the busiest U.S. border crossings. The Peace Bridge plaza on the U.S. side is a complex of roads, customs inspection areas, passport control areas, and duty-free shops. On average 5000 heavy-duty diesel trucks and 20,000 passenger cars traverse the border daily, making the plaza area a potential "hot spot" for emissions from mobile sources. In a series of winter and summer field campaigns, we measured air pollutants, including many compounds considered by the U.S. Environmental Protection Agency (EPA*) as mobile-source air toxics (MSATs), at three fixed sampling sites: on the shore of Lake Erie, approximately 500 m upwind (under predominant wind conditions) of the Peace Bridge plaza; immediately downwind of (adjacent to) the plaza; and 500 m farther downwind, into the community of west Buffalo. Pollutants sampled were particulate matter (PM) < or = 10 microm (PM10) and < or = 2.5 microm (PM2.5) in aerodynamic diameter, elemental carbon (EC), 28 elements, 25 volatile organic compounds (VOCs) including 3 carbonyls, 52 polycyclic aromatic hydrocarbons (PAHs), and 29 nitrogenated polycyclic aromatic hydrocarbons (NPAHs). Spatial patterns of counts of ultrafine particles (UFPs, particles < 0.1 microm in aerodynamic diameter) and of particle-bound PAH (pPAH) concentrations were assessed by mobile monitoring in the neighborhood adjacent to the Peace Bridge plaza using portable instruments and Global Positioning System (GPS) tracking. The study was designed to assess differences in upwind and downwind concentrations of MSATs, in areas near the Peace Bridge plaza on the U.S. side of the border. The Buffalo Peace Bridge Study featured good access to monitoring locations proximate to the plaza and in the community, which are downwind with the dominant winds from the direction of Lake Erie and southern Ontario. Samples from the lakeside Great Lakes Center (GLC), which is upwind of the plaza with dominant winds, were used to characterize contaminants in regional air masses. On-site meteorologic measurements and hourly truck and car counts were used to assess the role of traffic on UFP counts and pPAH concentrations. The array of parallel and perpendicular residential streets adjacent to the plaza provided a grid on which to plot the spatial patterns of UFP counts and pPAH concentrations to determine the extent to which traffic emissions from the Peace Bridge plaza might extend into the neighboring community. For lake-wind conditions (southwest to northwest) 12-hour integrated daytime samples showed clear evidence that vehicle-related emissions at the Peace Bridge plaza were responsible for elevated downwind concentrations of PM2.5, EC, and benzene, toluene, ethylbenzene, and xylenes (BTEX), as well as 1,3-butadiene and styrene. The chlorinated VOCs and aldehydes were not differentially higher at the downwind site. Several metals (aluminum, calcium, iron, copper, and antimony) were two times higher at the site adjacent to the plaza as they were at the upwind GLC site on lake-wind sampling days. Other metals (beryllium, sodium, magnesium, potassium, titanium, manganese, cobalt, strontium, tin, cesium, and lanthanum) showed significant increases downwind as well. Sulfur, arsenic, selenium, and a few other elements appeared to be markers for regional transport as their upwind and downwind concentrations were correlated, with ratios near unity. Using positive matrix factorization (PMF), we identified the sources for PAHs at the three fixed sampling sites as regional, diesel, general vehicle, and asphalt volatilization. Diesel exhaust at the Peace Bridge plaza accounted for approximately 30% of the PAHs. The NPAH sources were identified as nitrate (NO3) radical reactions, diesel, and mixed sources. Diesel exhaust at the Peace Bridge plaza accounted for 18% of the NPAHs. Further evidence for the impact of the Peace Bridge plaza on local air quality was found when the differences in 10-minute average UFP counts and

Spengler, John; Lwebuga-Mukasa, Jamson; Vallarino, Jose; Melly, Steve; Chillrud, Steve; Baker, Joel; Minegishi, Taeko

2011-07-01

400

Assessing air quality inside vehicles and at filling stations by monitoring benzene, toluene, ethylbenzene and xylenes with the use of semipermeable devices.  

PubMed

BTEX (benzene, toluene, ethylbenzene, and xylenes) were used as target molecules to evaluate the quality of air inside motor vehicles and near filling stations, using semipermeable membrane devices (SPMDs) as low-cost passive sampling devices. A direct, fast, simple methodology based on the use of headspace-gas chromatography-mass spectrometry detection (HS-GC-MS) was developed for BTEX determinations, without any sample pre-treatment. SPMDs (25.4 cm2 surface, filled with 100 microL triolein) were employed as static samplers. After the selected deployment time, the SPMDs were heated inside a HS vial at 150 degrees C for 20 min and BTEX compounds were determined by GC-MS in selected ion monitoring (SIM) mode in less than 12 min. The proposed method provides limits of detection of less than 1 ng SPMD(-1) for all compounds studied; which is equivalent to 0.3-8 ng m(-3) in air for a deployment time of 24 h, and to 9-200 microg m(-3) for 10 min time, as a function of the compound considered. Using sampling times of around 24 h, concentrations from 0.2 to 145 microg m(-3) were measured inside motor vehicles. For exposure times from 2 to 40 min, concentrations of BTEX ranging from 0.03 to 79 mg m(-3) were measured at filling stations, especially during refueling of vehicles with gasoline. PMID:17531831

Esteve-Turrillas, Francesc A; Pastor, Agustín; de la Guardia, Miguel

2007-06-12

401

The best for the guest: high Andean nurse cushions of Azorella madreporica enhance arbuscular mycorrhizal status in associated plant species  

Microsoft Academic Search

Positive interactions between cushion plant and associated plants species in the high Andes of central Chile should also include\\u000a the effects of fungal root symbionts. We hypothesized that higher colonization by arbuscular mycorrhizal (AM) fungi exists\\u000a in cushion-associated (nursling) plants compared with conspecific individuals growing on bare ground. We assessed the AM status\\u000a of Andean plants at two sites at

M. Angélica Casanova-Katny; Gustavo Adolfo Torres-Mellado; Goetz Palfner; Lohengrin A. Cavieres

402

Fine and landscape-scale spatial genetic structure of cushion rockjasmine, Androsace tapete (Primulaceae), across southern Qinghai-Tibetan Plateau  

Microsoft Academic Search

The cushion rockjasmine, Androsace tapete (Primulaceae), is among the angiosperms with highest altitudal distribution in the world. Cushion rockjasmine is a prominent\\u000a pioneer species in alpine deserts and alpine flowstone slope habitats up to 5,300 m on Qinghai-Tibetan Plateau. In this study,\\u000a we use inter simple sequence repeat (ISSR) markers to investigate the spatial genetic structure of A. tapete at

Yupeng Geng; Shaoqing Tang; Tsering Tashi; Zhiping Song; Guangrong Zhang; Liyan Zeng; Jiayuan Zhao; Li Wang; Jing Shi; Jiakuan Chen; Yang Zhong

2009-01-01

403

UPDATED PHOTOCHEMICAL MODELING FOR CALIFORNIA'S SOUTH COAST AIR BASIN: COMPARISON OF CHEMICAL MECHANISMS AND MOTOR VEHICLE EMISSION INVENTORIES. (R824792)  

EPA Science Inventory

Large uncertainties remain in photochemical models used to relate emissions of VOC and NO x to ambient O3 concentrations. Bias in motor vehicle emission estimates for VOC has been a long-standing concern. An improved Eul...

404

PREDICTING THE RELATIVE IMPACTS OF URBAN DEVELOPMENT POLICIES AND ON-ROAD VEHICLE TECHNOLOGIES ON AIR QUALITY IN  

E-print Network

14 2.3 Air Quality Modeling Predictions 15 2.3.1 Daily Maximum 1-hour Ozone Concentrations 16 2 ON AIR QUALITY IN THE UNITED STATES: MODELING AND ANALYSIS OF A CASE STUDY IN AUSTIN, TEXAS Final Report.6 Air Quality Modeling Predictions 67 4.0 Conclusions 71 5.0 Publications/Presentations 74 6

Kockelman, Kara M.

405

An Innovative Approach for Data Collection and Handling to Enable Advancements in Micro Air Vehicle Persistent Surveillance  

E-print Network

Vehicle Persistent Surveillance. (August 2009) Ryan David Goodnight, B.S., Texas A&M University Chair of Advisory Committee: Dr. Helen Reed The success of unmanned aerial vehicles (UAV) in the Iraq and Afghanistan conflicts has led to increased... successful on larger UAVs such as the RQ-11 Raven but have proven to be very demanding of the operator. By implementing a new and iv innovative data processing methodology, currently existing hardware can be adapted to effectively present critical...

Goodnight, Ryan David

2010-10-12

406

Effects of Composition Levels on the Cellular Structure and the Thermal Properties of Biodegradable Cushioning Extrudates  

Microsoft Academic Search

Response surface methodology (RSM) was used to analyze the effect of polyvinyl alcohol (PVA) and calcium carbonate (CaCO3) on the cellular structure and the thermal properties of a biodegradable cushioning extrudate. A central-composite design (CCD) was used to develop models for the objective responses. The experiments were run at 105 C with a feed rate of 27.8 L\\/h, a screw

Wai-Bun Lui; Jinchyau Peng

2004-01-01

407

Volatile organic chemical emissions from carpet cushions: Screening measurements. Final report  

SciTech Connect

The US Consumer Product Safety Commission (CPSC) has received complaints from consumers regarding the occurrence of adverse health effects following the installation of new carpeting (Schachter, 1990). Carpet systems are suspected of emitting chemicals which may be the cause of these complaints, as well as objectionable odors. Carpets themselves have been shown to emit a variety of volatile organic compounds (VOCs). The objective of this study was to screen the representative samples of carpet cushions for emissions of individual VOCS, total VOCs (TVOC), formaldehyde, and, for the two types of polyurethane cushions, isomers of toluene diisocyanate (TDI). The measurements of VOCS, TVOC and formaldehyde were made over six-hour periods using small-volume (4-L) dynamic chambers. Sensitive gas chromatography-mass spectrometry (GC-MS) techniques were used to identify many of the VOCs emitted by the cushion samples and to obtain quantitative estimates of the emission rates of selected compounds. Separate screening measurements were conducted for TDI. The data from the screening measurements were used by the CPSC`s Health Sciences Laboratory to help design and conduct week-long measurements of emission rates of selected compounds.

Hodgson, A.T.; Phan, T.A.

1994-05-01

408

Behaviour of Load-Bearing Components of a Cushioned Composite Piled Raft Foundation Under Axial Loading  

NASA Astrophysics Data System (ADS)

In the last decade piled raft foundations have been widely used around the world as intermediate foundation systems between piles and rafts to control the settlement of foundations. However, when those piles are structurally connected to rafts, relatively high axial stresses develop in relatively small numbers of piles, which are often designed to fully mobilize their geotechnical capacities. To avoid a concentration of stress at the head of piles in a traditional piled raft foundation, the raft is disconnected from the piles, and a cushion is introduced between them. Also, to tackle an unfavourable soil profile for a piled raft foundation, the conventional piled raft has been modified into a cushioned composite piled raft foundation, where piles of different materials are used. In the current study the behavior of cushioned foundation components, which transfer the load from the structure to the subsoil, are analyzed in detail, i.e., the thickness of the raft, the length of a long pile and the modulus of a flexible pile.

Sharma, V. J.; Vasanvala, S. A.; Solanki, C. H.

2014-12-01

409

Yap1 is required for endothelial to mesenchymal transition of the atrioventricular cushion.  

PubMed

Cardiac malformations due to aberrant development of the atrioventricular (AV) valves are among the most common forms of congenital heart diseases. Normally, heart valve mesenchyme is formed from an endothelial to mesenchymal transition (EMT) of endothelial cells of the endocardial cushions. Yes-associated protein 1 (YAP1) has been reported to regulate EMT in vitro, in addition to its known role as a major regulator of organ size and cell proliferation in vertebrates, leading us to hypothesize that YAP1 is required for heart valve development. We tested this hypothesis by conditional inactivation of YAP1 in endothelial cells and their derivatives. This resulted in markedly hypocellular endocardial cushions due to impaired formation of heart valve mesenchyme by EMT and to reduced endocardial cell proliferation. In endothelial cells, TGF? induces nuclear localization of Smad2/3/4 complex, which activates expression of Snail, Twist1, and Slug, key transcription factors required for EMT. YAP1 interacts with this complex, and loss of YAP1 disrupts TGF?-induced up-regulation of Snail, Twist1, and Slug. Together, our results identify a role of YAP1 in regulating EMT through modulation of TGF?-Smad signaling and through proliferative activity during cardiac cushion development. PMID:24831012

Zhang, Hui; von Gise, Alexander; Liu, Qiaozhen; Hu, Tianyuan; Tian, Xueying; He, Lingjuan; Pu, Wenjuan; Huang, Xiuzhen; He, Liang; Cai, Chen-Leng; Camargo, Fernando D; Pu, William T; Zhou, Bin

2014-07-01

410

Energy absorption capability of foam-based composite materials and their applications as seat cushions in aircraft crashworthiness  

NASA Astrophysics Data System (ADS)

This study is focusing on the application of foam materials in aviation. These materials are being used for acoustic purposes, as padding in the finished interior panels of the aircraft, and as seat cushions. Foams are mostly used in seating applications. Since seat cushion is directly interacting with the body of occupant, it has to be ergonomically comfortable beside of absorbing the energy during the impact. All the seats and seat cushions have to pass regulations defined by Federal Aviation Administration (FAA). In fact, all airplane companies are required to certify the subcomponents of aircrafts before installing them on the main structure, fuselage. Current Federal Aviation Administration Regulations require a dynamic sled test of the entire seat system for certifying the seat cushions. This dynamic testing is required also for replacing the deteriorated cushions with new cushions. This involves a costly and time-consuming certification process. AGATE group has suggested a procedure based on quasi-static testing in order to certify new seat cushions without conducting full-scale dynamic sled testing. AGATE subcomponent methodology involves static tests of the energy-absorbing foam cushions and design validation by conducting a full-scale dynamic seat test. Microscopic and macroscopic studies are necessary to provide a complete understanding about performance of foams during the crash. Much investigation has been done by different sources to obtain the reliable modeling in terms of demonstration of mechanical behavior of foams. However, rate sensitivity of foams needs more attention. A mathematical hybrid dynamic model for the cushion underneath of the human body will be taken into consideration in this research. Analytical and finite element codes such as MADYMO and LS-DYNA codes have the potential to greatly speed up the crashworthy design process, to help certify seats and aircraft to dynamic crash loads, to predict seat and occupant response to impact with the probability of injury, and to evaluate numerous crash scenarios not economically feasible with full-scale crash testing. Therefore, these codes are being used to find the accurate response of spinal load during the impact of model including human body, seat cushion and seat under different acceleration pulses. (Abstract shortened by UMI.)

Kh. Beheshti, Hamid

411

Membrane-Based Air Composition Control for Light-Duty Diesel Vehicles: A Benefit and Cost Assessment  

SciTech Connect

This report presents the methodologies and results of a study conducted by Argonne National Laboratory (Argonne) to assess the benefits and costs of several membrane-based technologies. The technologies evaluated will be used in automotive emissions-control and performance-enhancement systems incorporated into light-duty diesel vehicle engines. Such engines are among the technologies that are being considered to power vehicles developed under the government-industry Partnership for a New Generation of Vehicles (PNGV). Emissions of nitrogen oxides (NO{sub x}) from diesel engines have long been considered a barrier to use of diesels in urban areas. Recently, particulate matter (PM) emissions have also become an area of increased concern because of new regulations regarding emissions of particulate matter measuring 2.5 micrometers or less (PM{sub 2.5}). Particulates are of special concern for diesel engines in the PNGV program; the program has a research goal of 0.01 gram per mile (g/mi) of particulate matter emissions under the Federal Test Procedure (FTP) cycle. This extremely low level (one-fourth the level of the Tier II standard) could threaten the viability of using diesel engines as stand-alone powerplants or in hybrid-electric vehicles. The techniques analyzed in this study can reduce NO{sub x} and particulate emissions and even increase the power density of the diesel engines used in light-duty diesel vehicles.

K. Stork; R. Poola

1998-10-01

412

Low-cost multi-vehicle air temperature measurements for heat load assessment in local-scale climate applications  

NASA Astrophysics Data System (ADS)

In the recent years there has been a strong interest in exploring the potential of low-cost measurement devices as alternative source of meteorological monitoring data, especially in the urban areas where high-density observations become crucial for appropriate heat load assessment. One of the simple, but efficient approaches for gathering large amount of spatial data is through mobile measurement campaigns in which the sensors are attached to driving vehicles. However, non-standardized data collecting procedure, instrument quality, their response-time and design, variable device ventilation and radiation protection influence the reliability of the gathered data. We investigate what accuracy can be expected from the data collected through low-cost mobile measurements and whether the achieved quality of the data is sufficient for validation of the state-of-the-art local-scale climate models. We tested 5 types of temperature sensors and data loggers: Maxim iButton, Lascar EL-USB-2-LCD+ and Onset HOBO UX100-003 as market available devices and self-designed solar powered Arduino-based data loggers combined with the AOSONG AM2315 and Sensirion SHT21 temperature and humidity sensors. The devices were calibrated and tested in stationary mode at the Austrian Weather Service showing accuracy between 0.1°C and 0.8°C, which was mostly within the device specification range. In mobile mode, the best response-time was found for self-designed device with Arduino-based data logger and Sensirion SHT21 sensor. However, the device lacks the mechanical robustness and should be further improved for broad-range applications. We organized 4 measurement tours: two taking place in urban environment (Vienna, Austria in July 2011 and July 2013) and two in countryside with complex terrain of Mid-Adriatic islands (Hvar and Korcula, Croatia in August 2013). Measurements were taken on clear-sky, dry and hot days. We combined multiple devices attached to bicycle and cars with different radiation protection. Duration of each measurement tour lasted approximately 2 hours covering the distances in radius of about 10-30 km, logging the air temperature and geographical positioning in intervals of 1-5 seconds. The collected data were aggregated on a 100 m horizontal resolution grid and compared with the local-scale climate modelling simulations with the urban climate model MUKLIMO3 initialized with the atmospheric conditions for a given day. Both measurement and modelling results show similar features for distinct local climate zones (built-up area, near water environment, forest, parks, agricultural area, etc). The spatial gradients in temperature can be assigned to different orographical and land use characteristics. Even if many ambiguities remain in both modelling and the measurement approach, the collected data provide useful information for local-scale heat assessment and can serve as a base to increase the model reliability, especially in areas with low data coverage.

Zuvela-Aloise, Maja; Weyss, Gernot; Aloise, Giulliano; Mifka, Boris; Löffelmann, Philemon; Hollosi, Brigitta; Nemec, Johana; Vucetic, Visnja

2014-05-01

413

Metal-Air Electric Vehicle Battery: Sustainable, High-Energy Density, Low-Cost Electrochemical Energy Storage – Metal-Air Ionic Liquid (MAIL) Batteries  

SciTech Connect

Broad Funding Opportunity Announcement Project: ASU is developing a new class of metal-air batteries. Metal-air batteries are promising for future generations of EVs because they use oxygen from the air as one of the battery’s main reactants, reducing the weight of the battery and freeing up more space to devote to energy storage than Li-Ion batteries. ASU technology uses Zinc as the active metal in the battery because it is more abundant and affordable than imported lithium. Metal-air batteries have long been considered impractical for EV applications because the water-based electrolytes inside would decompose the battery interior after just a few uses. Overcoming this traditional limitation, ASU’s new battery system could be both cheaper and safer than today’s Li-Ion batteries, store from 4-5 times more energy, and be recharged over 2,500 times.

None

2009-12-21

414

Radar-Based Detection and Identification for Miniature Air Vehicles Allistair Moses, Matthew J. Rutherford, Kimon P. Valavanis  

E-print Network

sense- and-avoid mechanisms, including detection and identification of other UAV-sized targets and ultrasonic rangefinders. These sensors are generally not able to detect or identify other UAV-sized targets enough to detect other UAV-sized vehicles, and (3) intelligent enough to identify and differentiate

Minnesota, University of

415

Variations in speciated emissions from spark-ignition and compression-ignition motor vehicles in California's south coast air basin.  

PubMed

The U.S. Department of Energy Gasoline/Diesel PM Split Study examined the sources of uncertainties in using an organic compound-based chemical mass balance receptor model to quantify the contributions of spark-ignition (SI) and compression-ignition (CI) engine exhaust to ambient fine particulate matter (PM2.5). This paper presents the chemical composition profiles of SI and CI engine exhaust from the vehicle-testing portion of the study. Chemical analysis of source samples consisted of gravimetric mass, elements, ions, organic carbon (OC), and elemental carbon (EC) by the Interagency Monitoring of Protected Visual Environments (IMPROVE) and Speciation Trends Network (STN) thermal/optical methods, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, alkanes, and polar organic compounds. More than half of the mass of carbonaceous particles emitted by heavy-duty diesel trucks was EC (IMPROVE) and emissions from SI vehicles contained predominantly OC. Although total carbon (TC) by the IMPROVE and STN protocols agreed well for all of the samples, the STN/IMPROVE ratios for EC from SI exhaust decreased with decreasing sample loading. SI vehicles, whether low or high emitters, emitted greater amounts of high-molecular-weight particulate PAHs (benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and coronene) than did CI vehicles. Diesel emissions contained higher abundances of two- to four-ring semivolatile PAHs. Diacids were emitted by CI vehicles but are also prevalent in secondary organic aerosols, so they cannot be considered unique tracers. Hopanes and steranes were present in lubricating oil with similar composition for both gasoline and diesel vehicles and were negligible in gasoline or diesel fuels. CI vehicles emitted greater total amounts of hopanes and steranes on a mass per mile basis, but abundances were comparable to SI exhaust normalized to TC emissions within measurement uncertainty. The combustion-produced high-molecular-weight PAHs were found in used gasoline motor oil but not in fresh oil and are negligible in used diesel engine oil. The contributions of lubrication oils to abundances of these PAHs in the exhaust were large in some cases and were variable with the age and consumption rate of the oil. These factors contributed to the observed variations in their abundances to total carbon or PM2.5 among the SI composition profiles. PMID:17608006

Fujita, Eric M; Zielinska, Barbara; Campbell, David E; Arnott, W Patrick; Sagebiel, John C; Mazzoleni, Lynn; Chow, Judith C; Gabele, Peter A; Crews, William; Snow, Richard; Clark, Nigel N; Wayne, W Scott; Lawson, Douglas R

2007-06-01

416

Autonomous vehicles  

SciTech Connect

There are various kinds of autonomous vehicles (AV`s) which can operate with varying levels of autonomy. This paper is concerned with underwater, ground, and aerial vehicles operating in a fully autonomous (nonteleoperated) mode. Further, this paper deals with AV`s as a special kind of device, rather than full-scale manned vehicles operating unmanned. The distinction is one in which the AV is likely to be designed for autonomous operation rather than being adapted for it as would be the case for manned vehicles. The authors provide a survey of the technological progress that has been made in AV`s, the current research issues and approaches that are continuing that progress, and the applications which motivate this work. It should be noted that issues of control are pervasive regardless of the kind of AV being considered, but that there are special considerations in the design and operation of AV`s depending on whether the focus is on vehicles underwater, on the ground, or in the air. The authors have separated the discussion into sections treating each of these categories.

Meyrowitz, A.L. [Navy Center for Applied Research in Artificial Intelligence, Washington, DC (United States)] [Navy Center for Applied Research in Artificial Intelligence, Washington, DC (United States); Blidberg, D.R. [Autonomous Undersea Systems Inst., Lee, NH (United States)] [Autonomous Undersea Systems Inst., Lee, NH (United States); Michelson, R.C. [Georgia Tech Research Inst., Smyrna, GA (United States)] [Georgia Tech Research Inst., Smyrna, GA (United States); [International Association for Unmanned Vehicle Systems, Smyrna, GA (United States)

1996-08-01

417

Crystallization Behavior of M97 Series Silicone Cushions  

SciTech Connect

M97 series siloxanes are poly(dimethyl-diphenyl) siloxanes that are reinforced through a mixture of precipitated and fumed silica fillers which are blended in through the addition of a short chain polydimethylsiloxane processing aid. M97 silicones exhibit crystallization at -80.25 C by thermal (modulated differential scanning calorimetry) and mechanical (dynamic mechanical analysis) techniques. Isothermal dynamic mechanical analysis experiments illustrated that crystallization occurred over a 1.8 hour period in silica-filled systems and 2.8 hours in unfilled systems. The onset of crystallization typically occurred after a 30 minute incubation/nucleation period. {gamma}-radiation caused the crystallization rate to decrease proportionally with dosage, but did not decrease the amount of crystallization that ultimately occurred. Irradiation in vacuum resulted in slower overall crystallization rates compared to air irradiation due to increased crosslinking of the polymer matrix under vacuum. Modulated differential scanning calorimetry contrasted the crystallization and melting behavior of pure PDMS versus the M97 base polymer and helped determine which component of the composite was the origin of the crystallization phenomena.

Chien, A.; DeTeresa, S.; Cohenour, R.; Schnieder, J.; LeMay, J.; Balazs, B.

2000-09-07

418

Effects of floral neighborhood on seed set and degree of outbreeding in a high-alpine cushion plant.  

PubMed

Plants flowering together may influence each other's pollination and fecundity over a range of physical distances. Their effects on one another can be competitive, neutral, or facilitative. We manipulated the floral neighborhood of the high-alpine cushion plant Eritrichium nanum in the Swiss Alps and measured the effects of co-flowering neighbors on both the number of seeds produced and the degree of inbreeding and outbreeding in the offspring, as deduced from nuclear microsatellite markers. Seed set of E. nanum did not vary significantly with the presence or absence of two Saxifraga species growing as near neighbors, but it was higher in E. nanum cushions growing at low conspecific density than in those growing at high density. In addition, floral neighborhood had no detectable effect on the degree of selfing of E. nanum, but seeds from cushions growing at low conspecific density were more highly outbred than seeds from cushions at high density. Thus, there was no evidence of either competition or facilitation between E. nanum and Saxifraga spp. as mediated by pollinators at the spatial scale of our experimental manipulation. In contrast, the greater fecundity of E. nanum cushions at low density was consistent with reduced intraspecific competition for pollinators and might also represent a beneficial effect of highly outbred seeds as brought about by more long-distance pollinator flights under low-density conditions. PMID:21484399

Wirth, Lea R; Waser, Nickolas M; Graf, René; Gugerli, Felix; Landergott, Urs; Erhardt, Andreas; Linder, Hans Peter; Holderegger, Rolf

2011-10-01

419

N-Acetyl-S-(n-Propyl)-L-Cysteine in Urine from Workers Exposed to 1-Bromopropane in Foam Cushion Spray Adhesives  

PubMed Central

1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, metal, precision, and electronics cleaning solvents. Mechanisms of toxicity of 1-BP are not fully understood, but it may be a neurological and reproductive toxicant. Sparse exposure information prompted this study using 1-BP air sampling and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. Research objectives were to evaluate the utility of urinary N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys) for assessing exposure to 1-BP and compare it to urinary bromide [Br(?)] previously reported for these workers. Forty-eight-hour urine specimens were obtained from 30 workers at two factories where 1-BP spray adhesives were used to construct polyurethane foam seat cushions. Urine specimens were also obtained from 21 unexposed control subjects. All the workers' urine was collected into composite samples representing three time intervals: at work, after work but before bedtime, and upon awakening. Time-weighted average (TWA) geometric mean breathing zone concentrations were 92.4 and 10.5 p.p.m. for spraying and non-spraying jobs, respectively. Urinary AcPrCys showed the same trend as TWA exposures to 1-BP: higher levels were observed for sprayers. Associations of AcPrCys concentrations, adjusted for creatinine, with 1-BP TWA exposure were statistically significant for both sprayers (P < 0.05) and non-sprayers (P < 0.01). Spearman correlation coefficients for AcPrCys and Br(?) analyses determined from the same urine specimens were highly correlated (P < 0.0001). This study confirms that urinary AcPrCys is an important 1-BP metabolite and an effective biomarker for highly exposed foam cushion workers. PMID:19706636

Hanley, Kevin W.; Petersen, Martin R.; Cheever, Kenneth L.; Luo, Lian

2009-01-01

420

N-acetyl-S-(n-propyl)-l-cysteine in urine from workers exposed to 1-bromopropane in foam cushion spray adhesives.  

PubMed

1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, metal, precision, and electronics cleaning solvents. Mechanisms of toxicity of 1-BP are not fully understood, but it may be a neurological and reproductive toxicant. Sparse exposure information prompted this study using 1-BP air sampling and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. Research objectives were to evaluate the utility of urinary N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys) for assessing exposure to 1-BP and compare it to urinary bromide [Br((-))] previously reported for these workers. Forty-eight-hour urine specimens were obtained from 30 workers at two factories where 1-BP spray adhesives were used to construct polyurethane foam seat cushions. Urine specimens were also obtained from 21 unexposed control subjects. All the workers' urine was collected into composite samples representing three time intervals: at work, after work but before bedtime, and upon awakening. Time-weighted average (TWA) geometric mean breathing zone concentrations were 92.4 and 10.5 p.p.m. for spraying and non-spraying jobs, respectively. Urinary AcPrCys showed the same trend as TWA exposures to 1-BP: higher levels were observed for sprayers. Associations of AcPrCys concentrations, adjusted for creatinine, with 1-BP TWA exposure were statistically significant for both sprayers (P < 0.05) and non-sprayers (P < 0.01). Spearman correlation coefficients for AcPrCys and Br((-)) analyses determined from the same urine specimens were highly correlated (P < 0.0001). This study confirms that urinary AcPrCys is an important 1-BP metabolite and an effective biomarker for highly exposed foam cushion workers. PMID:19706636

Hanley, Kevin W; Petersen, Martin R; Cheever, Kenneth L; Luo, Lian

2009-10-01

421

The politics of consensus-building : case study of diesel vehicles and urban air pollution in South Korea  

E-print Network

Look at the three efforts to resolve public disputes over diesel passenger cars and urban air quality management in South Korea. this dissertation explores the main obstacles in nascent democracies to meeting the necessary ...

Kim, Dong-Young, Ph. D. Massachusetts Institute of Technology

2006-01-01

422

Influence of mobile air-conditioning on vehicle emissions and fuel consumption: a model approach for modern gasoline cars used in Europe.  

PubMed

The influence of air-conditioning activity on the emissions and fuel consumption of passenger cars is an important issue, since fleet penetration and use of these systems have reached a high level. Apart from the MOBILE6 study in the United States, little data is available on the impact of air-conditioning devices (A/Cs). Since weather conditions and A/C technologies both differ from those in the U. S., a test series was designed for the European setting. A fleet of six modern gasoline passenger cars was tested in different weather conditions. Separate test series were carried out for the initial cooldown and for the stationary situation of keeping the interior of the vehicle cool. As assumed, CO2 emissions and fuel consumption rise with the thermal load. This also causes a notable rise in CO and hydrocarbons (HCs). Moreover, A/Cs do not stop automatically at low ambient temperatures; if necessary, they produce dry air to demist the windscreen. A model is proposed that shows a constant load for lower temperatures and a linear trend for higher temperatures. The initial cooldown tests highlight significant differences among cars but show that A/C operation for the initial cooling of an overheated passenger compartment does not result in any extra emissions for the fleet as a whole. PMID:16475341

Weilenmann, Martin F; Vasic, Ana-Marija; Stettler, Peter; Novak, Philippe

2005-12-15

423

40 CFR 86.1828-01 - Emission data vehicle selection.  

Code of Federal Regulations, 2012 CFR

...and the potential impact of air conditioning on test results. The selected vehicle will include an air conditioning engine code unless the worst-case...selected is not available with air conditioning. This vehicle...

2012-07-01

424

40 CFR 86.1828-01 - Emission data vehicle selection.  

Code of Federal Regulations, 2014 CFR

...and the potential impact of air conditioning on test results. The selected vehicle will include an air conditioning engine code unless the worst-case...selected is not available with air conditioning. This vehicle...

2014-07-01

425

40 CFR 86.1828-01 - Emission data vehicle selection.  

Code of Federal Regulations, 2013 CFR

...and the potential impact of air conditioning on test results. The selected vehicle will include an air conditioning engine code unless the worst-case...selected is not available with air conditioning. This vehicle...

2013-07-01

426

40 CFR 86.1828-01 - Emission data vehicle selection.  

Code of Federal Regulations, 2011 CFR

...and the potential impact of air conditioning on test results. The selected vehicle will include an air conditioning engine code unless the worst-case...selected is not available with air conditioning. This vehicle...

2011-07-01

427

40 CFR 86.1828-01 - Emission data vehicle selection.  

Code of Federal Regulations, 2010 CFR

...and the potential impact of air conditioning on test results. The selected vehicle will include an air conditioning engine code unless the worst-case...selected is not available with air conditioning. This vehicle...

2010-07-01

428

A synergistic glance at the prospects of distributed propulsion technology and the electric aircraft concept for future unmanned air vehicles and commercial/military aviation  

NASA Astrophysics Data System (ADS)

Distributed propulsion is one of the revolutionary candidates for future aircraft propulsion. In this journal article, the potential role of distributed propulsion technology in future aviation is investigated. Following a historical journey that revisits distributed propulsion technology in unmanned air vehicles and military aircraft, features of this specific technology are highlighted in synergy with an electric aircraft concept and a first-of-a-kind comparison to commercial aircraft employing distributed propulsion arrangements. In light of propulsion-airframe integration and complementary technologies such as boundary layer ingestion, thrust vectoring and circulation control, transpired opportunities and challenges are addressed in addition to a number of identified research directions proposed for future aircraft. The motivation behind enhanced means of communication between engineers, researchers and scientists has stimulated a novel proposed definition for the distributed propulsion technology in aviation and is presented herein.

Gohardani, Amir S.

2013-02-01

429

Aerothermodynamic Testing of Protuberances and Penetrations on the NASA Crew Exploration Vehicle Heat Shield in the NASA Langley 20-Inch Mach 6 Air Tunnel  

NASA Technical Reports Server (NTRS)

An experimental wind tunnel program is being conducted in support of an Agency wide effort to develop a replacement for the Space Shuttle and to support the NASA s long-term objective of returning to the moon and then on to Mars. This paper documents experimental measurements made on several scaled ceramic heat transfer models of the proposed Crew Exploration Vehicle. Global heat transfer images and heat transfer distributions obtained using phosphor thermography were used to infer interference heating on the Crew Exploration Vehicle Cycle 1 heat shield from local protuberances and penetrations for both laminar and turbulent heating conditions. Test parametrics included free stream Reynolds numbers of 1.0x10(exp 6)/ft to 7.25x10(exp 6)/ft in Mach 6 air at a fixed angle-of-attack. Single arrays of discrete boundary layer trips were used to trip the boundary layer approaching the protuberances/penetrations to a turbulent state. Also, the effects of three compression pad diameters, two radial locations of compression pad/tension tie location, compression pad geometry, and rotational position of compression pad/tension tie were examined. The experimental data highlighted in this paper are to be used to validate CFD tools that will be used to generate the flight aerothermodynamic database. Heat transfer measurements will also assist in the determination of the most appropriate engineering methods that will be used to assess local flight environments associated with protuberances/penetrations of the CEV thermal protection system.

Liechty, Derek S.

2008-01-01

430

Daily Exposure to Air Pollutants in Indoor, Outdoor and In-vehicle Micro-environments: A Pilot Study in Delhi  

Microsoft Academic Search

The study measures exposure to air pollution in an urban setting in India. Integrated daily exposure to respirable suspended particulates (RSP) and carbon monoxide (CO) was assessed by personal and area sampling from six micro-environments including those for which prior data did not exist in India. This is also one of few studies that have measured the exposure of commuters

Sumeet Saksena; Raj Kumar Prasad; V. Ravi Shankar

2007-01-01

431

Cushions of Thylacospermum caespitosum (Caryophyllaceae) do not facilitate other plants under extreme altitude and dry conditions in the north-west Himalayas  

PubMed Central

Background Cushion plants are commonly considered as keystone nurse species that ameliorate the harsh conditions they inhabit in alpine ecosystems, thus facilitating other species and increasing alpine plant biodiversity. A literature search resulted in 25 key studies showing overwhelming facilitative effects of different cushion plants and hypothesizing greater facilitation with increased environmental severity (i.e. higher altitude and/or lower rainfall). At the same time, emerging ecological theory alongside the cushion-specific literature suggests that facilitation might not always occur under extreme environmental conditions, and especially under high altitude and dryness. Methods To assess these hypotheses, possible nursing effects of Thylacospermum caespitosum (Caryophyllaceae) were examined at extremely high altitude (5900 m a.s.l.) and in dry conditions (precipitation <100 mm year?1) in Eastern Ladakh, Trans-Himalaya. This is, by far, the highest site, and the second driest, at which the effects of cushions have been studied so far. Key Results In accordance with the theoretical predictions, no nursing effects of T. caespitosum on other alpine plants were detected. The number and abundance of species were greater outside cushions than within and on the edge of cushions. None of the 13 species detected was positively associated with cushions, while nine of them were negatively associated. Plant diversity increased with the size of the area sampled outside cushions, but no species–area relationship was found within cushions. Conclusions The results support the emerging theoretical prediction of restricted facilitative effects under extreme combinations of cold and dryness, integrating these ideas in the context of the ecology of cushion plants. This evidence suggests that cases of missing strong facilitation are likely to be found in other extreme alpine conditions. PMID:21813564

de Bello, Francesco; Doležal, Ji?í; Dvorský, Miroslav; Chlumská, Zuzana; ?eháková, Klára; Klimešová, Jitka; Klimeš, Leoš

2011-01-01

432

Computer graphic of Lockheed Martin X-33 Reusable Launch Vehicle (RLV) mounted on NASA 747 ferry air  

NASA Technical Reports Server (NTRS)

This is an artist's conception of the NASA/Lockheed Martin X-33 Advanced Technology Demonstrator being carried on the back of the 747 Shuttle Carrier Aircraft. This was a concept for moving the X-33 from its landing site back to NASA's Dryden Flight Research Center, Edwards, California. The X-33 was a technology demonstrator vehicle for the Reusable Launch Vehicle (RLV). The RLV technology program was a cooperative agreement between NASA and industry. The goal of the RLV technology program was to enable significant reductions in the cost of access to space, and to promote the creation and delivery of new space services and other activities that will improve U.S. economic competitiveness. NASA Headquarter's Office of Space Access and Technology oversaw the RLV program, which was being managed by the RLV Office at NASA's Marshall Space Flight Center, located in Huntsville, Alabama. Responsibilities of other NASA Centers included: Johnson Space Center, Houston, Texas, guidance navigation and control technology, manned space systems, and health technology; Ames Research Center, Mountain View, CA., thermal protection system testing; Langley Research Center, Langley, Virginia, wind tunnel testing and aerodynamic analysis; and Kennedy Space Center, Florida, RLV operations and health management. Lockheed Martin's industry partners in the X-33 program are: Astronautics, Inc., Denver, Colorado, and Huntsville, Alabama; Engineering & Science Services, Houston, Texas; Manned Space Systems, New Orleans, LA; Sanders, Nashua, NH; and Space Operations, Titusville, Florida. Other industry partners are: Rocketdyne, Canoga Park, California; Allied Signal Aerospace, Teterboro, NJ; Rohr, Inc., Chula Vista, California; and Sverdrup Inc., St. Louis, Missouri.

1997-01-01

433

Tbx20 acts upstream of Wnt signaling to regulate endocardial cushion formation and valve remodeling during mouse cardiogenesis  

PubMed Central

Cardiac valves are essential to direct forward blood flow through the cardiac chambers efficiently. Congenital valvular defects are prevalent among newborns and can cause an immediate threat to survival as well as long-term morbidity. Valve leaflet formation is a rigorously programmed process consisting of endocardial epithelial-mesenchymal transformation (EMT), mesenchymal cell proliferation, valve elongation and remodeling. Currently, little is known about the coordination of the diverse signals that regulate endocardial cushion development and valve elongation. Here, we report that the T-box transcription factor Tbx20 is expressed in the developing endocardial cushions and valves throughout heart development. Ablation of Tbx20 in endocardial cells causes severe valve elongation defects and impaired cardiac function in mice. Our study reveals that endocardial Tbx20 is crucial for valve endocardial cell proliferation and extracellular matrix development, but is not required for initiation of EMT. Elimination of Tbx20 also causes aberrant Wnt/?-catenin signaling in the endocardial cushions. In addition, Tbx20 regulates Lef1, a key transcriptional mediator for Wnt/?-catenin signaling, in this developmental process. Our study suggests a model in which Tbx20 regulates the Wnt pathway to direct endocardial cushion maturation and valve elongation, and provides new insights into the etiology of valve defects in humans. PMID:23824573

Cai, Xiaoqiang; Zhang, Weijia; Hu, Jun; Zhang, Lu; Sultana, Nishat; Wu, Bingruo; Cai, Weibin; Zhou, Bin; Cai, Chen-Leng

2013-01-01

434

Direct compression of cushion-layered ethyl cellulose-coated extended release pellets into rapidly disintegrating tablets without changes in the release profile.  

PubMed

The aim of this study was to develop and optimize a segregation-free ethyl cellulose-coated extended release multiparticulate formulation to be compressed into tablets without affecting the drug release. Standard tableting excipients (e.g., microcrystalline cellulose, lactose or sorbitol) were layered onto ethyl cellulose-coated propranolol hydrochloride pellets to form a cushion layer in order to eliminate segregation problems normally resulting from particle size difference between coated pellets and excipient powders and second to protect the integrity of the brittle ethyl cellulose coating during compression. The disintegration behavior of the tablets depended strongly on the composition of the cushion layer. Rapid tablet disintegration was obtained with microcrystalline cellulose and the disintegrant sodium croscarmellose. However, the drug release from these cushion-layered pellets still increased upon compression. Incorporation of a glidant into the cushion layer or between the cushion layer and the ethyl cellulose coating reduced the compression effect on drug release markedly. Glidant-containing formulations showed a delayed deformation and damage of the ethyl cellulose-coated pellet upon mechanical stress. In summary, cushion layer based on microcrystalline cellulose facilitated segregation-free compression of a highly compression-sensitive extended release ethyl cellulose-coated pellets into fast-disintegrating and hard tablets without compromising the release properties of the multiparticulates. Directly compressible cushion-layered pellets protected the pellet coating significantly better from damages during tabletting when compared to the conventional compression of blends of coated pellets and excipient powders. PMID:23892153

Hosseini, Armin; Körber, Martin; Bodmeier, Roland

2013-12-01

435

Population rules can apply to individual plants and affect their architecture: an evaluation on the cushion plant Mulinum spinosum (Apiaceae)  

PubMed Central

Background and aims Plants are regarded as populations of modules such as axes and growth units (GUs, i.e. seasonally produced axis segments). Due to their dense arrays of GUs, cushion plants may resemble crowded plant populations in the way the number of components (GUs in plants, individuals in populations) relates to their individual sizes. Methodology The morphological differentiation of GUs and its relationship with biomass accumulation and plant size were studied for the cushion subshrub Mulinum spinosum (Apiaceae), a widespread species in dry areas of Patagonia. In 2009, GUs were sampled from one-quarter of each of 24 adult plants. Within- and between-plant variations in GU length, diameter, number of nodes and biomass were analysed and related to whole-plant size. Principal results Each year, an M. spinosum cushion develops flowering GUs and vegetative GUs. Flowering GUs are larger, twice as numerous and contain two to four times more dry mass (excluding reproductive structures) than vegetative GUs. The hemispherical area of the cushions was positively correlated with the biomass of last-year GUs. The biomass of flowering GUs was negatively correlated with the density of GUs. Mulinum spinosum plants exhibited a notable differentiation between flowering and vegetative GUs, but their axes, i.e. the sequences of GUs, were not differentiated throughout the plants. Flowering GUs comprised a major proportion of each plant's photosynthetic tissues. Conclusions A decrease in the size of flowering GUs and in their number relative to the total number of GUs per plant, parallel to an increase in GU density, is predicted as M. spinosum plants age over years. The assimilative role of vegetative GUs is expected to increase in summer because of their less exposed position in the cushion. These GUs would therefore gain more from warm and dry conditions than flowering GUs. PMID:22476077

Puntieri, Javier G.; Damascos, María A.; Llancaqueo, Yanina; Svriz, Maya

2010-01-01

436

Modal analysis of an artificial wing mimicking an Allomyrina dichotoma beetle's hind wing for flapping-wing micro air vehicles by noncontact measurement techniques  

NASA Astrophysics Data System (ADS)

Recently, the development of flapping-wing micro air vehicles (FW-MAV) for operation in extreme environmental conditions has demanded properly designed, biologically inspired wings that can produce enough lift force to keep the vehicles aloft. The structural analysis of an artificial wing is carried out in the design of an FW-MAV. In this study, the dynamic characteristics of an artificial wing mimicking an Allomyrina dichotoma beetle's hind wing were investigated by a non-contact measurement method. The natural frequencies, mode shapes, and damping ratios of the first three basic vibration modes in the operating frequency range were determined using a Bruel & Kjaer (B&K) fast Fourier transform analyzer, along with a laser sensor. The laser sensor was used to obtain the displacement history of the marked points on the wing to calculate the frequency response function. To confirm the results, a three-dimensional digital image correlation (3D-DIC) method, as well as high speed digital cameras, were employed to construct the mode shapes of the wing when it was vibrated at a pre-determined natural frequency. The mode shapes by the DIC method showed good agreement with those by the laser displacement sensor. These results provide a method for the modal analysis of a light weight structure like an insect wing as well as for the construction of the mode shapes using DIC. The high speed 3D-DIC method, used successfully in mode shape measurements, can also be used to study the wing deformation of an insect during flight, which is challenging in an insect study.

Ha, Ngoc San; Jin, Tailie; Goo, Nam Seo

2013-05-01

437

75 FR 18142 - Approval and Promulgation of Air Quality Implementation Plans; Texas; Control of Air Pollution...  

Federal Register 2010, 2011, 2012, 2013, 2014

...FRL-9135-5] Approval and Promulgation of Air Quality Implementation Plans; Texas; Control of Air Pollution From Motor Vehicles AGENCY...Administrative Code (TAC), Chapter 114, Control of Air Pollution from Motor Vehicles. The...

2010-04-09

438

Magnitude and value of electric vehicle emissions reductions for six driving cycles in four US cities with varying air quality problems  

SciTech Connect

The emissions of logically competing mid-1990 gasoline vehicles (GVs) and electric vehicles (EVs) are estimated as if the vehicles were driven in the same pattern of driving. Six different driving cycles are evaluated, ranging in speed from 7 to 49 miles per hour (mph). These steps are repeated using specifics of fuel composition, electric power mix, and environmental conditions applicable to Chicago, Denver, Los Angeles, and New York in the month of July. The year 2000 emissions differences for each of four regulated pollutants - HC, CO, NO{sub x,} SO{sub x} - are estimated. CO{sub 2} emissions are also estimated. With use of EVs, HC and CO emissions are consistently lowered by 98% or more. CO{sub 2} emissions reductions are uniformly large at low speed, but variable at high speed. It is found that initially introduced EVs could achieve 100% emission reductions in Chicago by using off-peak power from nuclear power plants for EV electricity generation. Emissions reductions occur for all combinations in Los Angeles, and for most combinations in New York, excepting SO{sub x}. NO{sub x} emissions are reduced in all four cities. An ``avoided cost`` value for each regulated pollutant is estimated for each of the cities. The values for each city depend on severity of air quality violations. It is estimated that the emissions reduction value of EVs driven an average of one and one half hours per day in Los Angeles ranges from $1050 to $3,900; $590 to $2100 in New York; $270 to $1200 in Chicago, and $330 to $1250 in Denver (1989$). Assuming a range of about 100 miles in congested conditions with speeds of 10 mph or less, the estimates range from $3600 to $13300 for Los Angeles; $2004 to $7200 for New York; $930 to $2930 for Chicago; and $1120 to $4290 for Denver. Low estimates are obtained using EPA`s draft Mobile5 model for GV emissions, high values by using California`s EMFAC7EP-SCF1 model. The dollar value benefit estimates include no economic value.

Wang, Q. [California Univ., Davis, CA (United States); Santini, D.L. [Argonne National Lab., IL (United States)

1992-12-31

439

Magnitude and value of electric vehicle emissions reductions for six driving cycles in four US cities with varying air quality problems  

SciTech Connect

The emissions of logically competing mid-1990 gasoline vehicles (GVs) and electric vehicles (EVs) are estimated as if the vehicles were driven in the same pattern of driving. Six different driving cycles are evaluated, ranging in speed from 7 to 49 miles per hour (mph). These steps are repeated using specifics of fuel composition, electric power mix, and environmental conditions applicable to Chicago, Denver, Los Angeles, and New York in the month of July. The year 2000 emissions differences for each of four regulated pollutants - HC, CO, NO[sub x,] SO[sub x] - are estimated. CO[sub 2] emissions are also estimated. With use of EVs, HC and CO emissions are consistently lowered by 98% or more. CO[sub 2] emissions reductions are uniformly large at low speed, but variable at high speed. It is found that initially introduced EVs could achieve 100% emission reductions in Chicago by using off-peak power from nuclear power plants for EV electricity generation. Emissions reductions occur for all combinations in Los Angeles, and for most combinations in New York, excepting SO[sub x]. NO[sub x] emissions are reduced in all four cities. An avoided cost'' value for each regulated pollutant is estimated for each of the cities. The values for each city depend on severity of air quality violations. It is estimated that the emissions reduction value of EVs driven an average of one and one half hours per day in Los Angeles ranges from $1050 to $3,900; $590 to $2100 in New York; $270 to $1200 in Chicago, and $330 to $1250 in Denver (1989$). Assuming a range of about 100 miles in congested conditions with speeds of 10 mph or less, the estimates range from $3600 to $13300 for Los Angeles; $2004 to $7200 for New York; $930 to $2930 for Chicago; and $1120 to $4290 for Denver. Low estimates are obtained using EPA's draft Mobile5 model for GV emissions, high values by using California's EMFAC7EP-SCF1 model. The dollar value benefit estimates include no economic value.

Wang, Q. (California Univ., Davis, CA (United States)); Santini, D.L. (Argonne National Lab., IL (United States))

1992-01-01

440

An adaptive dual-optimal path-planning technique for unmanned air vehicles with application to solar-regenerative high altitude long endurance flight  

NASA Astrophysics Data System (ADS)

A multi-objective technique for Unmanned Air Vehicle (UAV) path and trajectory autonomy generation, through task allocation and sensor fusion has been developed. The Dual-Optimal Path-Planning (D-O.P-P.) Technique generates on-line adaptive flight paths for UAVs based on available flight windows and environmental influenced objectives. The environmental influenced optimal condition, known as the driver' determines the condition, within a downstream virtual window of possible vehicle destinations and orientation built from the UAV kinematics. The intermittent results are pursued by a dynamic optimization technique to determine the flight path. This sequential optimization technique is a multi-objective optimization procedure consisting of two goals, without requiring additional information to combine the conflicting objectives into a single-objective. An example case-study and additional applications are developed and the results are discussed; including the application to the field of Solar Regenerative (SR) High Altitude Long Endurance (HALE) UAV flight. Harnessing solar energy has recently been adapted for use on high altitude UAV platforms. An aircraft that uses solar panels and powered by the sun during the day and through the night by SR systems, in principle could sustain flight for weeks or months. The requirements and limitations of solar powered flight were determined. The SR-HALE UAV platform geometry and flight characteristics were selected from an existing aircraft that has demonstrated the capability for sustained flight through flight tests. The goals were to maintain continual Situational Awareness (SA) over a case-study selected Area of Interest (AOI) and existing UAV power and surveillance systems. This was done for still wind and constant wind conditions at altitude along with variations in latitude. The characteristics of solar flux and the dependence on the surface location and orientation were established along with fixed flight maneuvers for the SR-HALE UAV. A sustained turn circle flight pattern, common for vehicles in loiter was selected as a baseline for comparisons. The objectives of the D-O.P-P. Technique for SR-HALE flight were to determine the minimum required power flight paths to the predetermined location and orientation for obtaining maximum solar flux established by the 'driver.' The on-line path generation technique prolonged the flight duration, over the baseline by approximately two months for a year of flight over the case-study AOI. This prolonged flight was consistent for all latitude locations, including two months of available flight at 60 degree latitude---where sustained turn baseline flight was no longer capable. This was possible by increasing the total solar power by as much as 28% while decreasing the averaged power required for flight.

Whitfield, Clifford A.

2009-12-01

441

Comparison of cotton and acrylic socks using a generic cushion sole design for runners.  

PubMed

A longitudinal single-blind study was conducted to test the friction blister prevention properties of synthetic acrylic socks in a generic construction. This study serves as a comparison with the authors' previous work comparing acrylic and cotton socks in a patented padded construction. Twenty-seven long-distance runners provided data regarding dampness, temperature, friction blister incidence, severity, and size. Two different socks were tested; each was identical in every aspect of construction except the fiber content. One test sock was composed of 100% synthetic acrylic fibers, and the other was composed of 100% natural cotton fibers. These results were unsuccessful at demonstrating any superiority of cotton or acrylic fibers when knitting produced a generic "cushion sole" sock. The superiority of acrylic fibers has thus far been demonstrated only when sock knitting provides adequate anatomical padding [corrected]. PMID:8289142

Herring, K M; Richie, D H

1993-09-01

442

Launch vehicle effluent measurements during the May 12, 1977, Titan 3 launch at Air Force Eastern Test Range  

NASA Technical Reports Server (NTRS)

Airborne effluent measurements and cloud physical behavior for the May 21, 1977, Titan 3 launch from the Air Force Eastern Test Range, Fla. are presented. The monitoring program included airborne effluent measurements in situ in the launch cloud, visible and infrared photography of cloud growth and physical behavior, and limited surface collection of rain samples. Airborne effluent measurements included concentrations of HCl, NO, NOx, and aerosols as a function of time in the exhaust cloud. For the first time in situ particulate mass concentration and aerosol number density were measured as a function of time and size in the size range of 0.05 to 25 micro meters diameter. Measurement results were similar to those of earlier launch monitorings. Maximum HCl and NOx concentrations ranged from 10 ppm and 500 ppb, respectively, several minutes after launch to about 1 ppm and 100 ppb at 45 minutes after launch.

Gregory, G. L.; Bendura, R. J.; Woods, D. C.

1979-01-01

443

Endocardial Cushion Morphogenesis and Coronary Vessel Development Require Chicken Ovalbumin Upstream Promoter-Transcription Factor II  

PubMed Central

Objective Septal defects and coronary vessel anomalies are common congenital heart defects, yet their ontogeny and the underlying genetic mechanisms are not well understood. Here, we investigated the role of chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII, NR2F2) in cardiac organogenesis. Methods and Results We analyzed embryos deficient in COUP-TFII and observed a spectrum of cardiac defects, including atrioventricular septal defect, thin-walled myocardium, and abnormal coronary morphogenesis. We show by expression analysis that COUP-TFII is expressed in the endocardium and the epicardium but not in the myocardium of the ventricle. Using endothelial-specific COUP-TFII mutants and molecular approaches, we show that COUP-TFII deficiency resulted in endocardial cushion hypoplasia. This was attributed to the reduced growth and survival of atrioventricular cushion mesenchymal cells and defective epithelial-mesenchymal transformation (EMT) in the underlying endocardium. In addition, the endocardial EMT defect was accompanied by downregulation of Snai1, one of the master regulators of EMT, and upregulation of vascular endothelial-cadherin. Furthermore, we show that although COUP-TFII does not play a major role in the formation of epicardial cell cysts, it is critically important for the formation of epicardium. Ablation of COUP-TFII impairs epicardial EMT and coronary plexus formation. Conclusion Our results reveal that COUP-TFII plays cell-autonomous roles in the endocardium and the epicardium for endocardial and epicardial EMT, which are required for proper valve and coronary vessel formation during heart development. PMID:22962329

Lin, Fu-Jung; You, Li-Ru; Yu, Cheng-Tai; Hsu, Wen-Hsin; Tsai, Ming-Jer; Tsai, Sophia Y.

2013-01-01