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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

Nuclear air cushion vehicles.  

NASA Technical Reports Server (NTRS)

This paper serves several functions. It identifies the 'state-of-the-art' of the still-conceptual nuclear air cushion vehicle, particularly the nuclear powerplant. Using mission studies and cost estimates, the report describes some of the advantages of nuclear power for large air cushion vehicles. The paper also summarizes the technology studies on mobile nuclear powerplants and conceptual ACV systems/missions studies that have been performed at NASA Lewis Research Center.

Anderson, J. L.

1973-01-01

3

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

4

Air cushion vehicles - Any potential for Canada?  

NASA Astrophysics Data System (ADS)

The present evaluation of air cushion vehicle (ACV) operational and commercial suitability in the Canadian context notes that the most successful and durable ACV applications are those in which only ACVs can perform the required mission. An important factor is the reliability of the craft being tested in a given field of operations. Because of their low ground pressure, ACVs can operate over low-cost trails with an efficiency that compares with that of trucks over conventional roads; this renders them especially attractive for transportation networks in the North West Territories.

Laframboise, J. F.

1987-09-01

5

Air cushion vehicles for arctic operation  

NASA Astrophysics Data System (ADS)

Attention is given to the results of the NAVSEA FY85 Surface Ship Concept Formulation Design Study for an initial operational capability year-2000 air cushion vehicle (ACV) suitable for logistics and general search/rescue duties in the Arctic. Two designs were developed during the study; the first utilized an ACV design synthesis math model while the second evolved as a derivative of an existing U.S. production craft. Both are regarded as feasible from an engineering and naval architectural standpoint. Results of performance and cost trade-off studies suggest that, for an Arctic ACV, gas turbines are the preferred power plant choice and an aluminum alloy is the preferred hull structural material choice. The most appropriate skirt height is approximately 12 ft.

Koleser, J.; Lavis, D. R.

1986-09-01

6

Simulation study of plane motion of air cushion vehicle  

NASA Astrophysics Data System (ADS)

This research is on horizontal plane motion equations of Air Cushion Vehicle (ACV) and its simulation. To investigate this, a lot of simulation study including ACV’s voyage and turning performance has been done. It was found that the voyage simulation results were accorded with ACV own characteristic and turning simulation results were accorded with USA ACV’s movement characteristic basically.

Zhao, Shu-Qin; Shi, Xiao-Cheng; Shi, Yi-Long; Bian, Xin-Qian

2003-12-01

7

Developments in skirt systems for air cushion vehicles  

NASA Astrophysics Data System (ADS)

The present evaluation of the development status of air-cushion vehicle (ACV) skirts emphasizes the materials employed, with a view to the formulation of materials-performance requirements for next-generation AVCs and, in particular, an 'air-cushion catamaran' surface-effect ship (SES). Attention is given to novel skirt-design features which furnish substantial savings in maintenance costs. The employment of extant test rig data and the use of CAD methods are discussed, and the features of a novel system for the direct fixing of a bow finger onto an SES structure are noted.

Inch, Peter; Prentice, Mark E.; Lewis, Carol Jean

8

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

9

Thirty years of research and development of air cushion vehicles  

NASA Astrophysics Data System (ADS)

This paper describes the conception of the air cushion vehicle (ACV) from experiments with the ground effect of a VTOL aircraft model. Then it describes the evolution of the ultimate ACV drive system through building and testing many models and 16 full-scale ACV to arrive at complete controllability. Adequate control of the frictionless craft, which are without inherent yaw stability, requires control force of the order of magnitude of propulsion. The derived gimbal fans provide such control force in the form of direct thrust, which is instantly available in any of 360 degrees, meterable, instantly cancelable, and reversible.

Bertelsen, William R.

10

Creating new cities through the large air-cushion vehicle.  

NASA Technical Reports Server (NTRS)

The air-cushion vehicle (ACV) can travel over concrete roads, grass, sand, mud, swamp, snow, ice, and water. This mobility makes possible a totally new geographical freedom in choosing transportation routes, locating ports, and laying out a city. By the 1980s fleets of large ACV freighters could begin carrying ocean-going cargo. The mobility of an ACV fleet would allow placing hoverports away from areas now crowded. New cities could rise along shallow or reef-bound seacoasts and rivers, just as cities once rose around deep-water seaports.

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

1972-01-01

11

Computer-aided conceptual design of Air Cushion Vehicles  

NASA Astrophysics Data System (ADS)

This paper describes the development and use of a computer-aided design tool which has been used to explore preferred options for amphibious Air-Cushion Vehicle (ACV) and Surface-Effect Ship (SES) designs in support of U.S. Navy and U.S. Army programs. The tool, referred to as the ACV Design Synthesis Model (ADSM), is an interactive computer program which provides a description of feasible ACV or SES concepts that could be developed, by a competent design team, to perform the mission described by the input parameters. The paper discusses how the program was used to explore parametrically the design of a range of self-propelled hoverbarges to meet requirements of the U.S. Army Logistics Over the Shore (LOTS) phases of an amphibious landing. Examples of results are presented to illustrate the method used in determining design and performance trade-offs.

Band, E. G. U.; Lavis, D. R.

12

Linear Heave Dynamics of an Air-Cushion Vehicle Bag-and-Finger Skirt  

NASA Astrophysics Data System (ADS)

Results from a linear analysis of the heave dynamics of an air-cushion vehicle equipped with a bag-and-finger skirt are described. A two-dimensional section of the cushion is subject to pure heave or long-wave surface motion inputs. The skirt mass is lumped in the fingers, with the bag being modelled as a combination of massless inelastic membranes and links. The airflows from bag to cushion and from cushion to atmosphere are assumed quasisteady, and the bag and cushion volumes are modelled as lumped pneumatic capacitances. For a configuration representative of a 37t vehicle, frequency response characteristics show the effect of skirt geometry and mass changes, and cushion capacitance. The results suggest that changes in skirt geometry cannot be used to radically modify an undesirable heave response, but reducing the skirt mass may be effective. The air compressibility also affects heave response at high frequencies, with the effect becoming more prominent at the low cushion-flow rates now used in practice.

Chung, Joon; Sullivan, Phillip A.

13

An Analysis of Skill Requirements for Operators of Amphibious Air Cushion Vehicles (ACVs).  

ERIC Educational Resources Information Center

This report describes the skills required in the operation of an amphibious air cushion vehicle (ACV) in Army tactical and logistic missions. The research involved analyzing ACV characteristics, operating requirements, environmental effects, and results of a simulation experiment. The analysis indicates that ACV operation is complicated by an…

McKnight, A. James; And Others

14

Theoretical investigation of heave dynamics of an air cushion vehicle bag and finger skirt  

NASA Astrophysics Data System (ADS)

This thesis describes a theoretical investigation of the nonlinear and linear heave dynamics of an air cushion vehicle (ACV) equipped with a bag and finger skirt system with the purpose of understanding the skirt's effect on the vehicle heave dynamics. Throughout the course of this work, the pure heave motion of a two dimensional section of the skirt is investigated using several mathematical models. Both the nonlinear and linearized analyses include a detailed model of the skirt geometry, which is modelled as a combination of inelastic membranes and links. Air flow processes from the bag to the cushion and from the cushion to the atmosphere are assumed to be quasisteady, and the bag and cushion volumes are modelled as lumped pneumatic capacitances. The modulation of the escaping cushion air by skirt-ground contact is also included. The nonlinear simulations reveal that characteristically nonlinear dynamical phenomena such as period doubling and chaos can be expected to occur during the normal operation of ACVs. Furthermore, a configuration representative of a 37 tonne vehicle shows a resonance at frequencies in the range for which humans are most sensitive. Although these results thus show that some aspects of the bag and finger skirt heave dynamics can be highly nonlinear, they indicate that under certain circumstances, standard linear techniques can yield useful insights. Results from the linear analysis suggest that changes in skirt geometry cannot be used to radically modify the undesirable heave response of the bag and finger skirt, but reducing the skirt mass is quite effective. The pneumatic capacitance of the bag and cushion volume proves to be an important factor in the heave response. In particular, it contributes to heave instability. The air compressibility also affects heave response at high frequencies, with the effect becoming more prominent as the flow rate is reduced. The importance of unsteady fan effects on ACV dynamics is investigated by the application of a measured frequency response scaled from a small laboratory fan. The results showed that the unsteady fan has a significant impact on the heave response, and that it introduces major phase-shifts in the neighbourhood of the skirt resonance. These effects contribute to instability.

Chung, Joon

15

Finger materials for air cushion vehicles. Volume 1: Flexible coatings for finger materials  

NASA Astrophysics Data System (ADS)

Twenty polymer formulations from ten selected gum rubber polymers or polymer blends and fourteen formulations of castable liquid polyurethane polymers were characterized as coatings for the coated fabric that is the type material used to make flexible fingers for air cushion vehicles. The formulations were screened for crack growth and flexural fatigue resistance; the results were compared to results from a natural rubber/cisabutadiene blend control coating. In addition, selected polymers were evaluated with primary and secondary characterization tests and the results compared to results from the control formulation. One polymer also was used to evaluate the use of a reticulated carbon black to improve thermal conductivity. Several polymers had better crack growth resistance and a number had better flexural fatique resistance than the control polymer. A clorinated polyethylene polymer coated on nylon fabric had properties equivalent to the control polymer coated on nylon fabric. Hysteresis tests at different rates of deformation yielded results which suggested that the standard tests may not identify polymers with improved performance on air cushion vehicles. Woven fabric, knit, and mat structures were evaluated as reinforcements for polymer coatings; the knit and mat structures were not as efficient on a strength-to-weight basis as woven fabrics.

Conn, P. K.; Snell, I. C.; Klemens, W.

1984-12-01

16

MathCAD model for the estimation of cost and main characteristics of air-cushion vehicles in the preliminary design stage  

E-print Network

In the naval architecture terminology, the term ACV (Air Cushion Vehicle) refers to this category of vehicles, in which a significant portion of the weight (or all the weight) is supported by forces arising from air pressures ...

Gougoulidis, Georgios

2005-01-01

17

Progress report on Bertelsen research and development of an air cushion crawler all-terrain vehicle  

NASA Astrophysics Data System (ADS)

The ACV is an exceptional amphibian but it is not, nor is any other existing craft, an all-terrain vehicle (ATV). Using the best elements of the ACV in an air-cushion crawler tractor, a true ATV can be attained. A conventional crawler drive train will propel two tracks as pressurized, propulsive pontoons. The key to a successful ATV is in perfecting efficient, durable, sliding seals to allow the belt to move in its orbit around the track unit and maintain its internal pressure. After deriving the adequate seal, a 12 inch wide x 86 inch long endless rubber belt was fitted bilateral seals and slide plates with internal guide wheels fore and aft with a 21 inch wheel base. From this approximately one-quarter scale model, full-scale air track crawlers, true ATVs, of any size and capacity can be produced.

Bertelsen, W. R.

1987-06-01

18

Impact studies of a 1/3-scale model of an air cushion vehicle  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted to determine the effects of various parameters of the impact performance of a 1/3-scale dynamic model of an air cushion vehicle. Impact response was determined by measuring the maximum values of variables, including sidelobe, front lobe, and cavity pressures, normal acceleration, pitch and roll angles, and vertical displacement during impact, for various combinations of drop height, initial pitch and roll angles, and forward speed. Increasing initial pitch angle increased the maximum values of the front lobe pressure, normal acceleration, nose down pitch angle, and to some extent, vertical displacement, but it inversely affected the maximum cavity pressure. Increasing the drop height of the model increased the potential energy of the system and generally produced larger responses over the entire range of variables measured, except for the roll angle after impact, which remained constant. Forward speed had no effect on the impact performance of the model, except for essentially doubling the maximum nose down pitch angle after impact at the maximum speed tested.

Daugherty, R. H.

1985-01-01

19

Complete flow field computation around an ACV (air-cushion vehicle) using 3D VOF with Lagrangian propagation in computational domain  

Microsoft Academic Search

In this study an algorithm and a 3D solver is developed to solve the flow field around air-cushion vehicles (ACV) in vicinity of free surface. A single set of dimensionless equations is derived to handle both liquid and air phases in viscous 3D incompressible free surface flows in general curvilinear coordinates. The momentum equations are solved using the SIMPLE method

A. H. Nikseresht; M. M. Alishahi; H. Emdad

2008-01-01

20

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

21

A theoretical study of limit cycle oscillations of plenum air cushions  

NASA Astrophysics Data System (ADS)

Air cushion vehicles (ACV) are prone to the occurrence of dynamic instabilities which frequently appear as stable finite amplitude oscillations. The aim of this work is to ascertain if the non-linearities characteristics of ACV dynamics generate limit cycle oscillations for cushion systems operating at conditions for which a linear theory predicts instability. The types of non-linearity that can occur are discussed, and an analysis is presented for a single cell flexible skirted plenum chamber constrained to move in pure heave only. Two cushion feed cases are considered: a plenum box supply and a duct. The results obtained by a Galerkin/describing function analysis are compared with those generated by a full numerical simulation. For the plenum box supply system, it is shown that the limit cycles can be suppressed by using a piston to introduce high frequency small amplitude volume oscillations into the plenum chamber.

Hinchey, M. J.; Sullivan, P. A.

1981-11-01

22

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

23

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

24

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

25

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

26

Control systems for platform landings cushioned by air bags  

NASA Astrophysics Data System (ADS)

This report presents an exploratory mathematical study of control systems for airdrop platform landings cushioned by airbags. The basic theory of airbags is reviewed and solutions to special cases are noted. A computer program is presented, which calculates the time-dependence of the principal variables during a landing under the action of various control systems. Two existing control systems of open-loop type are compared with a conceptual feedback (closed-loop) system for a fairly typical set of landing conditions. The feedback controller is shown to have performance much superior to the other systems. The feedback system undergoes an interesting oscillation not present in the other systems, the source of which is investigated. Recommendations for future work are included.

Ross, Edward W.

1987-07-01

27

Fluid (Air/Water) Cushion Transportation Technology for Emplacing Heavy Canisters into Horizontal Disposal Drifts  

SciTech Connect

The disposal of certain types of radioactive waste canisters in a deep repository involves handling and emplacement of very heavy loads. The weight of these particular canisters can be in the order of 20 to 50 metric tons. They generally have to be handled underground in openings that are not much larger than the canisters themselves as it is time consuming and expensive to excavate and backfill large openings in a repository. This therefore calls for the development of special technology that can meet the requirements for safe operation at an industrial scale in restrained operating spaces. Air/water cushion lifting systems are used world wide in the industry for moving heavy loads. However, until now the technology needed for emplacing heavy cylindrical radioactive waste packages in bored drifts (with narrow annular gaps) has not been previously developed or demonstrated. This paper describes the related R and D work carried out by ANDRA (for air cushion technology) and by SKB and Posiva (for water cushion technology) respectively, mainly within the framework of the European Commission (EC) funded Integrated Project called ESDRED (6. European Framework Programme). The background for both the air and the water cushion applications is presented. The specific characteristics of the two different emplacement concepts are also elaborated. Then the various phases of the Test Programmes (including the Prototype phases) are detailed and illustrated for the two lifting media. Conclusions are drawn for each system developed and evaluated. Finally, based on the R and D experience, improvements deemed necessary for an industrial application are listed. The tests performed so far have shown that the emplacement equipment developed is operating efficiently. However further tests are required to verify the availability and the reliability of the equipment over longer periods of time and to identify the modifications that would be needed for an industrial application in a nuclear and mining environment. (authors)

Bosgiraud, J.M.; Seidler, W.K.; Londe, L. [ANDRA, 92 - Chatenay Malabry (France); Thurner, E.; Pettersson, S. [Swedish Nuclear Fuel and Waste Management Co (SKB), Stockholm (Sweden)

2008-07-01

28

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

29

Heave-pitch-roll analysis and testing of air cushion landing systems  

NASA Technical Reports Server (NTRS)

The analytical tools (analysis and computer simulation) needed to explain and predict the dynamic operation of air cushion landing systems (ACLS) is described. The following tasks were performed: the development of improved analytical models for the fan and the trunk; formulation of a heave pitch roll analysis for the complete ACLS; development of a general purpose computer simulation to evaluate landing and taxi performance of an ACLS equipped aircraft; and the verification and refinement of the analysis by comparison with test data obtained through lab testing of a prototype cushion. Demonstration of simulation capabilities through typical landing and taxi simulation of an ACLS aircraft are given. Initial results show that fan dynamics have a major effect on system performance. Comparison with lab test data (zero forward speed) indicates that the analysis can predict most of the key static and dynamic parameters (pressure, deflection, acceleration, etc.) within a margin of a 10 to 25 percent.

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

1978-01-01

30

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

31

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

32

Effect of a responsive skirt on air cushion vehicle seakeeping  

NASA Astrophysics Data System (ADS)

The skirt system, which will be excited to make a response motion under the outer disturbance, is treated as a passive control system, and the longitudinal motion equations of ACV are derived according to the control principle. The influence of the skirt response in waves on ACVs seaworthiness is analyzed in the paper. Some results are gotten that the greater vertical deflexion of skirt will make the response of heave, pitch motion and acceleration of the craft decreased a lot, but the horizontal deflexion will go the opposite way. The natural frequency of skirt plays an important role in seaworthiness improvement, the adoption of lower frequency skirt can make the frequency band of craft motion response narrower effectively. The matching of skirt parameters of bow and stern has a certain effect too.

Zhou, W. L.; Ma, T.

33

A survey of protective cushion usage in individuals with spinal cord injury while traveling in a motor vehicle and on a commercial airliner.  

PubMed

Objective While there are specific recommendations for pressure relieving cushions when seated in a wheelchair, there is a paucity of information regarding prescribed wheelchair cushions for persons with spinal cord injury (SCI) when traveling and not in their wheelchair seat. A questionnaire was designed to ascertain if individuals with SCI who are primarily wheelchair users utilize a prescribed wheelchair cushion when traveling in a motor vehicle (MV) or on a commercial airliner, as not utilizing one may be a causative factor in developing pressure ulcers. Design and setting Survey design in an outpatient SCI rehabilitation setting. Participants Full-time wheelchair users, with chronic (>1 year) SCI. Results Forty-two participants completed the survey, with a mean age of 39 years old and time post-injury of 10.4 years. All subjects used a prescribed wheelchair cushion when seated in their wheelchair. Twenty-seven subjects reported transferring to a MV seat (59.5% of sample), with 25 (92.6%) reporting not using a prescribed wheelchair cushion when sitting directly on the MV seat. For subjects who traveled on an airplane (n = 23-54.8%), 19 (82.6%) reported that they do not sit on a prescribed specialty cushion. Conclusion Persons with chronic SCI, who are primary wheelchair users, utilize prescribed wheelchair cushions when sitting in their wheelchair, but most do not utilize a prescribed wheelchair cushion when seated in a MV (if they transfer out of their chair) or on a airplane seat. Studies to determine the pressures over the bony prominences on their travel surfaces may need to be undertaken to see whether the pressures are appropriate, as they may be a source of skin breakdown. PMID:24621043

McClure, Isa A; Nieves, Jeremiah D; Kirshblum, Steven C

2014-11-01

34

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

35

Evaluation of wheelchair cushions by means of pressure distribution mapping.  

PubMed

We studied the seated buttock pressure distribution in six paraplegic patients by means of computerized pressure mapping. They were all male and their age ranged from 18 to 48 years old. Their level of paralysis varied from Th5 to L1. Five kinds of wheelchair cushions were studied: an air cushion, a contour cushion, a polyurethane foam cushion, a Cubicushion (which is made of polyurethane foams) and a silicone gel cushion. A tactile sensor consisting of 2064 matrices was used for measuring the buttock pressure distribution and the data was analyzed on a personal computer. Peak pressures measured for each cushion were as follows (in descending order): the Cubicushion, the polyurethane foam cushion, the contour cushion, the silicone gel cushion, and the air cushion. The areas of total contact measured for each cushion were as follows (in descending order): the air cushion, the silicone gel cushion, the polyurethane foam cushion, the contour cushion and the Cubicushion. Based on these findings, we conclude that the most advantageous cushion is the air cushion or the silicone gel cushion. Likewise, we conclude that the Cubicushion is not practical for pressure sore prevention. PMID:9810434

Takechi, H; Tokuhiro, A

1998-10-01

36

A Method to Keep Cushion Pressure under Control  

NASA Astrophysics Data System (ADS)

An effective method to keep cushion pressure constant under fluctuation of cushion volume of SES is proposed and examined experimentally. In general, the fluctuation is induced by wave pumping. In the method an air jet with the length equal to the width of the air cushion is adapted. The air cushion is formed by this jet and sealed at one side. On the other hand, the opposite side is sealed with a material like as a skirt. The air nozzle that supplies the air jet can revolve to control the cushion pressure. In experiments a two-dimensional air cushion model of SES was used, where the wave pumping was simulated by a piston. Angle of the air nozzle was changed dynamically to eliminate the fluctuation of cushion pressure occurred by the piston. The experimental results show that the fluctuation of the cushion pressure became drastically extinct. The availability of this method was cleared and proved.

Senba, Hiromitsu; Matsuo, Hideo; Matsuo, Kensuke; Kanazawa, Koji; Hiroe, Tetsuyuki; Fujiwara, Kazuhito

37

Intelligent Systems Software for Unmanned Air Vehicles  

E-print Network

classes of vehicles including autonomous underwater vehicles, autonomous ground vehicles, and unmanned airIntelligent Systems Software for Unmanned Air Vehicles Gregory L. Sinsley , Lyle N. Long , Albert F describes a software architecture for mission-level control of autonomous unmanned air vehicles (UAVs

38

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

39

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

40

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

41

Air quality impacts of electric vehicles  

Microsoft Academic Search

The potential air quality impacts of electric vehicles in North Carolina are evaluated considering both air pollution reductions from less use of internal combustion engine vehicles and also additional air pollution at electric power plants. Using a consumer survey of 260 households, estimates of EV sales at $20,000 per vehicle, $15,000 and $10,000 are first made. EV purchases are classified

D. T. Hartgen; M. Murthy; N. N. Y. Cheung; J. A. Patten

1994-01-01

42

Unmanned Ground Vehicle State Estimation using an Unmanned Air Vehicle  

Microsoft Academic Search

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 have extended perception, tracking, and mobility capabilities compared with UGVs. UGVs have more intimate mobility and manipulation capabilities. This paper presents the research that has been conducted in the collaboration of UAVs and UGVs. This

Donald K. Macarthur; Carl D. Crane

2007-01-01

43

Introduction of the air cushion vehicle 'Larus' to the North American market  

NASA Astrophysics Data System (ADS)

The 'Larus' ACV, which currently operates as a ferry in the Northern Baltic with a payload of 25 tonnes and 46 passengers, will be refurbished for operations in the Canadian Arctic. These modifications will encompass the incorporation of an Arctic-grade rubber skirt, additional fire and thermal insulation, more heating and washrooms for passenger compartments, a fire extinghuishing system, a second radar unit, and satellite navigation. A development history and performance evaluation of the Larus are given.

Makinen, E.; Wainwright, J.

44

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

45

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

46

Aluminum-air batteries for vehicles  

Microsoft Academic Search

The aluminum-air battery is an advanced electrochemical energy source in the early stages of development. The battery is potentially capable of providing an electric vehicle with the range, acceleration, and rapid refueling capability of today's automobile. The Lawrence Livermore National Laboratory leads this DOE-funded program with a major part of the research being conducted by industrial laboratories. Peak cell energy

E. Behrin; J. F. Cooper

1981-01-01

47

Evolutionary Route Planner for Unmanned Air Vehicles  

Microsoft Academic Search

Based on evolutionary computation, a novel real-time route planner for unmanned air vehicles is presented. In the evolutionary route planner, the individual candidates are evaluated with respect to the workspace so that the computation of the configuration space is not required. The planner incorporates domain-specific knowledge, can handle unforeseeable changes of the environment, and take into account different kinds of

Changwen Zheng; Lei Li; Fanjiang Xu; Fuchun Sun; Mingyue Ding

2005-01-01

48

Electric conversion vehicle air-conditioning project  

Microsoft Academic Search

This paper examines an air conditioning system for an electric vehicle. A 1985 Ford Lynx is the subject car. The design conditions are Orlando's 1% mean dry and wet bulb temperatures. The cooling load temperature difference method is used to calculate the heat gain using August data at 28° north latitude. To reduce the required power for the compressor, the

Paul T. Worthington; Karel Minnaar; Chuck Arnold

1995-01-01

49

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

50

Morphing Unmanned Air Vehicle Intelligent Shape and Flight Control  

E-print Network

Morphing Unmanned Air Vehicle Intelligent Shape and Flight Control John Valasek , Amanda Lampton and demonstrates a complete methodology for the control of a morphing unmanned air vehicle. The shape learning-of-freedom unmanned air vehicle dynamical model simulation is integrated with a constant strength source doublet panel

Valasek, John

51

Autonomous unmanned air vehicles (UAV) techniques  

NASA Astrophysics Data System (ADS)

The UAVs (Unmanned Air Vehicles) have great potentials in different civilian applications, such as oil pipeline surveillance, precision farming, forest fire fighting (yearly), search and rescue, boarder patrol, etc. The related industries of UAVs can create billions of dollars for each year. However, the road block of adopting UAVs is that it is against FAA (Federal Aviation Administration) and ATC (Air Traffic Control) regulations. In this paper, we have reviewed the latest technologies and researches on UAV navigation and obstacle avoidance. We have purposed a system design of Jittering Mosaic Image Processing (JMIP) with stereo vision and optical flow to fulfill the functionalities of autonomous UAVs.

Hsu, Ming-Kai; Lee, Ting N.

2007-04-01

52

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

53

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

54

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

55

An Intelligent Controller for Collaborative Unmanned Air Vehicles  

E-print Network

. In the Department of Defense roadmap for Unmanned Aerial Vehicles [1], lower downside risk and higher confidence of success are listed as two motiva- tors for the continued development of unmanned air systems. One wayAn Intelligent Controller for Collaborative Unmanned Air Vehicles Gregory L. Sinsley, Jodi A

56

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

SciTech Connect

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 crash cushions require extensive maintenance or expensive replacement parts driving costs up even more. This makes the development of a more cost-effective crash cushion a necessity. This study proposed an initial design for a low-cost, reusable crash cushion using recycled materials. Used tires and tire-derived materials were tested in both static and dynamic modes to evaluate their application in a crash cushion. Both proved to be able to sustain high loads and durable, making them good candidates for use in a crash cushion. However, the tire-derived pads had excessively high loads per unit deflection prohibiting their use in a crash cushion. This problem could be eliminated if voids were added to allow material to deflect more under loading. The used tires could be used effectively as energy absorbing elements in crash cushions or truck mounted attenuators (TMA`s) if compressed horizontally or vertically.

Habors, D.T.; Hossain, M.

1998-09-01

57

Highway Crash Cushions  

E-print Network

. D. Sign Post E. Guardrail? Outside F. Guardrail? Inside 2. CAR STALLED ? HIT BY ANOTHER VEHICLE 10 16* 3. THROWN OR FELL OUT 4 ~ PEDESTRIAN 5 ~ WRONG-WAY COLL. 6. ACROSS MEDIAN ACCIDENT 12 12 7 ~ HIT RAIL ? STRUCK BY ANOTHER VEHICLE 8.... D. Sign Post E. Guardrail? Outside F. Guardrail? Inside 2. CAR STALLED ? HIT BY ANOTHER VEHICLE 10 16* 3. THROWN OR FELL OUT 4 ~ PEDESTRIAN 5 ~ WRONG-WAY COLL. 6. ACROSS MEDIAN ACCIDENT 12 12 7 ~ HIT RAIL ? STRUCK BY ANOTHER VEHICLE 8...

White, Monroe Carlton

2012-06-07

58

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

59

Zinc air battery development for electric vehicles  

NASA Astrophysics Data System (ADS)

This document reports the progress and accomplishments of a 16 month program to develop a rechargeable zinc-air battery for electric vehicle propulsion, from October 1988 through January 1990. The program was the first stage in the transition of alkaline zinc electrode technology, invented at Lawrence Berkeley Laboratory, to private industry. The LBL invention teaches the use of a copper metal foam substrate for the zinc electrode, in combination with forced convection of electrolyte through the foam during battery operation. Research at LBL showed promise that this approach would avoid shape change (densification and dendrite growth), the primary failure mode of this electrode. The program comprised five tasks: (1) cell design, (2) capacity maximization, (3) cycle testing, (4) materials qualification, and (5) a cost/design study. The cell design contemplates a plate and frame stack, with alternating zinc and oxygen electrode frame assemblies between rigid end plates. A 200 Ah cell, as may be required for the EV application, would comprise a stack of five zinc and six oxygen electrode frame/assemblies.

Putt, Ronald A.

1990-05-01

60

The development of aluminum-air batteries for electric vehicles  

Microsoft Academic Search

Progress made toward the development of a viable aluminum-air battery system is presented. The general aluminum\\/air reaction is discussed. Results from aluminum anode and air cathode experiments are presented. Solids separation technology, a heat exchanger unit, and cell design are also discussed. The projected specific energy and power of the battery can provide electric vehicle driving ranges comparable to those

A. S. Homa; E. J. Rudd

1989-01-01

61

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

62

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

63

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

64

Design and analysis of a gyroscopically controlled micro air vehicle  

NASA Astrophysics Data System (ADS)

Much of the current research on micro air vehicle design relies on aerodynamic forces for attitude control. The aerodynamic environment in which micro air vehicles operate is characterized by a low Reynolds number and is not fully understood, resulting in decreased performance and efficiency when compared to large-scale vehicles. In this work, we propose a new rotary-wing micro air vehicle design that utilizes gyroscopic dynamics for attitude control. Unlike traditional micro air vehicles where attitude control moments are generated by aerodynamic control surfaces, the proposed vehicle will leverage the existing angular momentum of its rotating components to generate gyroscopic moments for controlling attitude. We explore this paradigm in an effort to reduce mechanical complexity that is inherent in blade pitch modulation mechanisms such as the swashplate, and to increase agility and possibly even efficiency when compared to state-of-the-art micro vertical-take-off-and-landing vehicles. The evolution of the mechanical design, including the evaluation of three prototypes that explore the use of gyroscopic attitude control, is presented along with a comprehensive dynamic and aerodynamic model of the third prototype. Two controllers that utilize gyroscopic moments are developed and tested in simulation. In addition, several experiments were performed using a VICON motion tracking system and off-board control. These results will also be presented.

Thorne, Christopher Everett

65

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

66

The International Micro Air Vehicle flight competition as autonomy benchmark  

E-print Network

diagonal), the maximum size of an air 1http://imav2013.org/ Level of control K Video based control: control as collision avoidance or hovering based on laser scanner or optical flow) 4 Autonomous flight controlThe International Micro Air Vehicle flight competition as autonomy benchmark Arnoud Visser

Visser, Arnoud

67

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

E-print Network

air vehicles (UAV), unmanned ground vehicles (UGV), unmanned spacecraft, and unmanned underwater1 Abstract--The need for intelligent unmanned vehicles has been steadily increasing. These vehicles, or autonomous vehicles, are becoming widely used in the military and civilian sectors. These include unmanned

68

Motor vehicle-related air toxics study. Draft report  

SciTech Connect

The report has been prepared in response to Section 202 (1) of the Clean Air Act. Specific pollutants or pollutant categories which are discussed in the report include benzene, formaldehyde, 1,3-butadiene, acetaldehyde, diesel and gasoline particulate matter, and gasoline vapors as well as selected metals and motor vehicle-related pollutants identified in Section 112 of the Clean Air Act. The focus of the report is carcinogenic risk from the pollutants. The study in the report attempts to summarize what is known about motor vehicle-related air toxics and to present all significant scientific opinion on each issue.

Brodowicz, P.; Carey, P.; Cook, R.; Somers, J.

1992-12-01

69

Assessment on motor vehicle emissions and air quality in Beijing  

SciTech Connect

It is occasionally reported that hourly ozone concentrations exceed the National Air Quality Standard (NAQS) of China in recent years in Beijing, which indicates that motor vehicle emissions are more and more important to the total air quality in urban area of Beijing. A deep investigation was carried out to collect the information on road status, vehicle number and types, fuel consumption, traffic condition, and vehicle management in Beijing, so that the real world emission factors (CO, HC, NO{sub x}) could be calculated by MOBILE5a model. The calculated results were comparable with limited testing data from other former researches. With a detailed survey on emissions from other sources such as oil refueling, plants HC emission, and other stationary sources, the emission inventory are established and further projected for the future years, thus the emission contribution rates are obtained for motor vehicle emissions. The results are given for different seasons and different areas in Beijing.

Lixin Fu; Jiming Hao; Kebin He; Dongquan He [Tsinghua Univ., Beijing (China)

1996-12-31

70

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

71

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

72

The aluminum-air battery for electric vehicles - An update  

NASA Astrophysics Data System (ADS)

The development of aluminum-air batteries as mechanically rechargeable power sources to be used in electric vehicles is discussed. The chemistry of the aluminum-air battery, which has a potential for providing the range, acceleration and rapid refueling capability of contemporary automobiles and is based on the reaction of aluminum metal with atmospheric oxygen in the presence of an aqueous sodium hydroxide/sodium aluminate electrolyte, is examined, and it is pointed out that the electric vehicle would be practically emissionless. The battery development program at the Lawrence Livermore National Laboratory, which includes evaluations of electrochemical and chemical phenomena, studies of the economics and energy balance of a transportation system based on aluminum, and power cell design and performance analysis, is presented. It is concluded that although difficult problems must be overcome before the technical and economic feasibility of aluminum-air batteries for electric vehicles can be established, projections indicate that the aluminum-air vehicle is potentially competitive with internal combustion vehicles powered by synthetic liquid fuels.

1980-11-01

73

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

74

Motor vehicle-related air toxics study. Final report  

SciTech Connect

Section 202 (1)(1) of the Clean Air Act (CAA), as amended (Section 206 of the Clean Air Act Amendments) (CAAA) of 1990 added paragraph (1) to Section 202 of the (CAA), directs the Environmental Protection Agency (EPA) to complete a study by May 15, 1992 of the need for, and feasibility of, controlling emissions of toxic air pollutants which are unregulated under the Act and associated with motor vehicles and motor vehicle fuels. The report has been prepared in response to Section 202 (1)(1). Specific pollutants or pollutant categories which are discussed in the report include benezene, formaldehyde, 1,3-butadiene, acetaldehyde, diesel particulate matter, gasoline particulate matter, and gasoline vapors as well as certain of the metals and motor vehicle-related pollutants identified in Section 112 of the Clean Air Act. The focus of the report is on carcinogenic risk. The study attempts to summarize what is known about motor vehicle-related air toxics and to present all significant scientific opinion on each issue.

Not Available

1993-04-01

75

The aluminum-air battery for electric vehicle propulsion  

Microsoft Academic Search

This report reviews the status of aluminum-air battery development and discusses the use of aluminum as a recyclable electrochemical fuel. The battery combines high specific energy (above 300 Wh\\/kg) and specific power (150-200 W\\/kg) with the capability of rapid refueling by addition of reactants. The objective is a commercially-feasible, general-purpose electric vehicle. Progress is reported in the scale-up of aluminum-air

J. F. Cooper; R. V. Homsy; J. H. Landrum

1980-01-01

76

Aluminum Air Battery for Electric Vehicle Propulsion.  

National Technical Information Service (NTIS)

The status of aluminum-air battery development and the use of aluminum as a recyclable electrochemical fuel are discussed. The battery combines high specific energy (above 300 Wh/kg) and specific power (150 to 200 W/kg) with the capability of rapid refuel...

J. F. Cooper, R. V. Homsy, J. H. Landrum

1980-01-01

77

Flush Air Data Sensing System for Trans-Atmospheric Vehicles  

NASA Astrophysics Data System (ADS)

With the emergence of multiple companies attempting to tap the space tourism market, as well as NASA's return to the moon initiative, an inexpensive but reliable means of determining wind relative vehicle attitude is becoming a necessity. The traditional means of obtaining air data (altitude, Mach number, angles of attack and sideslip) using fixed pitot probes and directional flow vanes is not viable for collecting data on high supersonic and hypersonic vehicles, due to the high temperatures and dynamic pressures. The solution is to use a matrix of flush mounted pressure ports on the vehicle nose or on an outboard wing leading edge. Since the ports will be located behind a detached shock wave at supersonic velocities, the temperatures will remain substantially lower. A Flush Air Data Sensing (FADS) system can also be used for subsonic conditions, although it must be calibrated for the effects of the vehicle geometry. The physics of air behavior and the mathematics of the solution algorithm will be presented. Several relevant examples of planned vehicles will be presented.

Ellsworth, Joel

2006-10-01

78

A pressure control scheme for air brakes in commercial vehicles  

E-print Network

This research is focused on developing a control scheme for regulating the pressure in the brake chamber of an air brake system found in most commercial vehicles like trucks, tractor-trailers and buses. Such a control scheme can be used...

Bowlin, Christopher Leland

2007-04-25

79

Dynamic network flow optimization models for air vehicle resource allocation  

Microsoft Academic Search

A weapon system consisting of a swarm of air vehicles whose mission is to search for, classify, attack, and perform battle damage assessment, is considered. It is assumed that the target field information is communicated to all the elements of the swarm as it becomes available. A network flow optimization problem is posed whose readily obtained solution yields the optimum

Kendall E. Nygard; Phillip R. Chandler; M. Pachter

2001-01-01

80

An Adaptive Path Planning Algorithm for Cooperating Unmanned Air Vehicles  

SciTech Connect

An adaptive path planning algorithm is presented for cooperating Unmanned Air Vehicles (UAVs) that are used to deploy and operate land-based sensor networks. The algorithm employs a global cost function to generate paths for the UAVs, and adapts the paths to exceptions that might occur. Examples are provided of the paths and adaptation.

Cunningham, C.T.; Roberts, R.S.

2000-09-12

81

Vision guided landing of an unmanned air vehicle  

Microsoft Academic Search

In this paper, we study the problem of using computer vision as a sensor to control the landing of an unmanned air vehicle (UAV). The vision problem we address is a special case of the general ego-motion estimation problem due to the fact that all feature points lie on a plane. We propose a new geometric estimation scheme for solving

Omid Shakerniatl; Yi Mat; T. John Koo; Joao Hespanha; S. Shankar Sastry

1999-01-01

82

Border patrol and surveillance missions using multiple unmanned air vehicles  

Microsoft Academic Search

In this paper, we propose hierarchical control architecture for a system that does border or perimeter patrol using unmanned air vehicles (AUV). By control architecture we mean a specific way of organizing the motion control and navigation functions performed by the UAV. It is convenient to organize the functions into hierarchical layers. This way, a complex design problem is partitioned

Anouck R. Girard; Adam S. Howell; J. Karl Hedrick

2004-01-01

83

Adaptive path planning algorithm for cooperating unmanned air vehicles  

SciTech Connect

An adaptive path planning algorithm is presented for cooperating Unmanned Air Vehicles (UAVs) that are used to deploy and operate land-based sensor networks. The algorithm employs a global cost function to generate paths for the UAVs, and adapts the paths to exceptions that might occur. Examples are provided of the paths and adaptation.

Cunningham, C T; Roberts, R S

2001-02-08

84

Coordinated target assignment and intercept for unmanned air vehicles  

Microsoft Academic Search

This paper presents an end-to-end solution to the cooperative control problem represented by the scenario where unmanned air vehicles (UAVs) are assigned to transition through known target locations in the presence of dynamic threats. The problem is decomposed into the subproblems of: 1) cooperative target assignment; 2) coordinated UAV intercept; 3) path planning; 4) feasible trajectory generation; and 5) asymp-

Randal W. Beard; Timothy W. McLain; Michael A. Goodrich; Erik P. Anderson

2002-01-01

85

A decomposition strategy for optimal coordination of unmanned air vehicles  

Microsoft Academic Search

The cooperative control of multiple unmanned air vehicles (UAVs) poses significant theoretical and technical challenges. This research addresses the specific problem of the coordination of rendezvous of multiple UAVs at a predetermined target location. The rendezvous problem is posed as an optimization problem where the objective is to maximize the survivability of the UAV team, while constraining the UAVs to

Timothy W. McLain; Phillip R. Chandler; Meir Pachter

2000-01-01

86

Flush Air Data Sensing System for Trans-Atmospheric Vehicles  

Microsoft Academic Search

With the emergence of multiple companies attempting to tap the space tourism market, as well as NASA's return to the moon initiative, an inexpensive but reliable means of determining wind relative vehicle attitude is becoming a necessity. The traditional means of obtaining air data (altitude, Mach number, angles of attack and sideslip) using fixed pitot probes and directional flow vanes

Joel Ellsworth

2006-01-01

87

Autostabilizing airframe articulation: Animal inspired air vehicle control  

E-print Network

with sensorimotor systems observed in nature. Animals are richly imbued with sensors, have many pointsAutostabilizing airframe articulation: Animal inspired air vehicle control Jonathan P. Dyhr, Noah J of articulation and are heavily over-actuated. In fact, the compliant nature of the body (or Plant) of most

Morgansen, Kristi

88

A zinc-air battery and flywheel zero emission vehicle  

SciTech Connect

In response to the 1990 Clean Air Act, the California Air Resources Board (CARB) developed a compliance plan known as the Low Emission Vehicle Program. An integral part of that program was a sales mandate to the top seven automobile manufacturers requiring the percentage of Zero Emission Vehicles (ZEVs) sold in California to be 2% in 1998, 5% in 2001 and 10% by 2003. Currently available ZEV technology will probably not meet customer demand for range and moderate cost. A potential option to meet the CARB mandate is to use two Lawrence Livermore National Laboratory (LLNL) technologies, namely, zinc-air refuelable batteries (ZARBs) and electromechanical batteries (EMBs, i. e., flywheels) to develop a ZEV with a 384 kilometer (240 mile) urban range. This vehicle uses a 40 kW, 70 kWh ZARB for energy storage combined with a 102 kW, 0.5 kWh EMB for power peaking. These technologies are sufficiently near-term and cost-effective to plausibly be in production by the 1999-2001 time frame for stationary and initial vehicular applications. Unlike many other ZEVs currently being developed by industry, our proposed ZEV has range, acceleration, and size consistent with larger conventional passenger vehicles available today. Our life-cycle cost projections for this technology are lower than for Pb-acid battery ZEVs. We have used our Hybrid Vehicle Evaluation Code (HVEC) to simulate the performance of the vehicle and to size the various components. The use of conservative subsystem performance parameters and the resulting vehicle performance are discussed in detail.

Tokarz, F.; Smith, J.R.; Cooper, J.; Bender, D.; Aceves, S.

1995-10-03

89

Analysis of Aeroelastic Flapping-Wing Signals for Micro Air-Vehicles.  

E-print Network

??Flapping-wing micro air-vehicles are being investigated for their potential to provide enhanced aerodynamic efficiency, maneuverability and gust tolerance. The flight dynamics of flapping-wing micro air-vehicles… (more)

Love, Robert

2009-01-01

90

9 CFR 3.88 - Primary conveyances (motor vehicle, rail, air, and marine).  

...2014-01-01 false Primary conveyances (motor vehicle, rail, air, and marine). 3.88 Section 3.88 Animals and...Standards § 3.88 Primary conveyances (motor vehicle, rail, air, and marine). (a) The animal cargo space...

2014-01-01

91

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

...2014-01-01 false Primary conveyances (motor vehicle, rail, air and marine). 3.114 Section 3.114 Animals and...Standards § 3.114 Primary conveyances (motor vehicle, rail, air and marine). (a) The animal cargo...

2014-01-01

92

9 CFR 3.37 - Primary conveyances (motor vehicle, rail, air, and marine).  

...2014-01-01 false Primary conveyances (motor vehicle, rail, air, and marine). 3.37 Section 3.37 Animals and...Standards § 3.37 Primary conveyances (motor vehicle, rail, air, and marine). (a) The animal cargo space...

2014-01-01

93

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

...2014-01-01 false Primary conveyances (motor vehicle, rail, air, and marine). 3.62 Section 3.62 Animals and...Standards § 3.62 Primary conveyances (motor vehicle, rail, air, and marine). (a) The animal cargo space...

2014-01-01

94

9 CFR 3.15 - Primary conveyances (motor vehicle, rail, air, and marine).  

...2014-01-01 false Primary conveyances (motor vehicle, rail, air, and marine). 3.15 Section 3.15 Animals and...Standards § 3.15 Primary conveyances (motor vehicle, rail, air, and marine). (a) The animal cargo space...

2014-01-01

95

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

...2014-01-01 false Primary conveyances (motor vehicle, rail, air, and marine). 3.138 Section 3.138 Animals...Standards § 3.138 Primary conveyances (motor vehicle, rail, air, and marine). (a) The animal cargo space...

2014-01-01

96

Clinical evaluation of the Hemi Wheelchair Cushion.  

PubMed

A foam cushion was designed for wheelchair users who propel their wheelchairs with the assistance of one lower extremity. It allows users to extend one hip to reach the ground without having to slide forward on the seat, thus maintaining a more erect posture. The cushion was evaluated to identify contraindications for its use. Eleven subjects (10 stroke patients and 1 patient with an above-the-knee amputation) were tested on the Hemi Wheelchair Cushion and on a second cushion chosen by their primary occupational therapists. Seat interface pressures, both before and after dynamic movement, sitting balance, and wheelchair mobility were measured for each cushion. An analysis of mean pressure values revealed no significant difference between the cushion (p = .80). Average pressures after dynamic movement showed a statistically significant difference from pressures before activity (p < .05). Subjective evaluation revealed that the Hemi Wheelchair Cushion did not adversely affect sitting balance or wheelchair mobility, and no contraindications for its use were identified. The results of this clinical evaluation indicate that the Hemi Wheelchair Cushion is an economical and appropriate option for wheelchair users who propel themselves with the assistance of one leg. PMID:8470743

Cron, L; Sprigle, S

1993-02-01

97

Aeroelastic topology optimization of membrane structures for micro air vehicles  

Microsoft Academic Search

This work considers the aeroelastic optimization of a membrane micro air vehicle wing through topology optimization. The low\\u000a aspect ratio wing is discretized into panels: a two material formulation on the wetted surface is used, where each panel can\\u000a be membrane (wing skin) or carbon fiber (laminate reinforcement). An analytical sensitivity analysis of the aeroelastic system\\u000a is used for the

Bret Stanford; Peter Ifju

2009-01-01

98

Static Finite Element Validation of a Flexible Micro Air Vehicle  

Microsoft Academic Search

The flexible-wing approach has proven to be a successful method for designing micro air vehicles. The wing’s passive deformation\\u000a under wind loads can allow for gust rejection, delayed stall, or improved longitudinal stability. As such, an accurate structural\\u000a model of the flexible wing can provide greater understanding of the aforementioned phenomena. This paper seeks to formulate\\u000a a static finite element

B. Stanford; R. Albertani; P. Ifju

2007-01-01

99

Real-time dynamic trajectory smoothing for unmanned air vehicles  

Microsoft Academic Search

This brief presents a real-time, feasible trajectory generation algorithm for unmanned air vehicles (UAVs) flying through a sequence of waypoints. The algorithm produces extremal trajectories that transition between straight-line path segments in a time-optimal fashion. In addition, the algorithm can be configured so that the dynamically feasible trajectory has the same path length as the straight-line waypoint path. Implementation issues

Erik P. Anderson; Randal W. Beard; Timothy W. McLain

2005-01-01

100

Comparative analysis of aluminum-air battery propulsion systems for passenger vehicles  

NASA Astrophysics Data System (ADS)

Three electric propulsion systems using an aluminum air battery were analyzed and compared to the internal combustion engine (ICE) vehicle. The engine and fuel systems of a representative five passenger highway vehicle were replaced conceptually by each of the three electric propulsion systems. The electrical vehicles were constrained by the computer simulation to be equivalent to the ICE vehicle in range and acceleration performance. The vehicle masses and aluminum consumption rates were then calculated for the electric vehicles and these data were used as figures of merit. The Al-air vehicles analyzed were (1) an Al-air battery only electric vehicle; (2) an Al-air battery combined with a nickel zinc secondary battery for power leveling and regenerative braking; and (3) an Al-air battery combined with a flywheel for power leveling and regenerative braking. All three electric systems compared favorably with the ICE vehicle.

Salisbury, J. D.; Behrin, E.; Kong, M. K.; Whisler, D. J.

1980-02-01

101

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

102

Intake air flow rate control system for an internal combustion engine of an automotive vehicle  

Microsoft Academic Search

Disclosed is an intake air flow rate control system for an internal combustion engine, including a means for detecting acceleration and deceleration of the vehicle and controlling the air flow rate in response to required air flow rate which is varied by acceleration and deceleration of the vehicle. The means temporarily operates to vary the air flow rate at the

Ikeuva

1983-01-01

103

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

Federal Register 2010, 2011, 2012, 2013

...heavy- duty vehicles) within the refrigeration and air-conditioning sector. This...subpart G). These sectors include: refrigeration and air conditioning; foam...CO 2 in the air conditioning or refrigeration systems of buses, trains, rail...

2012-06-06

104

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

105

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

106

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

107

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

108

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

...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

109

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

110

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

111

Comparative analysis of aluminum-air battery propulsion systems for passenger vehicles  

Microsoft Academic Search

Three electric propulsion systems using an aluminum air battery were analyzed and compared to the internal combustion engine (ICE) vehicle. The engine and fuel systems of a representative five passenger highway vehicle were replaced conceptually by each of the three electric propulsion systems. The electrical vehicles were constrained by the computer simulation to be equivalent to the ICE vehicle in

J. D. Salisbury; E. Behrin; M. K. Kong; D. J. Whisler

1980-01-01

112

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

113

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

114

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

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

Low Earth Orbit Raider (LER) winged air launch vehicle concept  

NASA Technical Reports Server (NTRS)

The need to launch small payloads into low earth orbit has increased dramatically during the past several years. The Low Earth orbit Raider (LER) is an answer to this need. The LER is an air-launched, winged vehicle designed to carry a 1500 pound payload into a 250 nautical mile orbit. The LER is launched from the back of a 747-100B at 35,000 feet and a Mach number of 0.8. Three staged solid propellant motors offer safe ground and flight handling, reliable operation, and decreased fabrication cost. The wing provides lift for 747 separation and during the first stage burn. Also, aerodynamic controls are provided to simplify first stage maneuvers. The air-launch concept offers many advantages to the consumer compared to conventional methods. Launching at 35,000 feet lowers atmospheric drag and other loads on the vehicle considerably. Since the 747 is a mobile launch pad, flexibility in orbit selection and launch time is unparalleled. Even polar orbits are accessible with a decreased payload. Most importantly, the LER launch service can come to the customer, satellites and experiments need not be transported to ground based launch facilities. The LER is designed to offer increased consumer freedom at a lower cost over existing launch systems. Simplistic design emphasizing reliability at low cost allows for the light payloads of the LER.

Feaux, Karl; Jordan, William; Killough, Graham; Miller, Robert; Plunk, Vonn

1989-01-01

117

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

118

Improving the aluminum-air battery system for use in electrical vehicles  

Microsoft Academic Search

The objectives of this study include improvement of the efficiency of the aluminum\\/air battery system and demonstration of its ability for vehicle applications. The aluminum\\/air battery system can generate enough energy and power for driving ranges and acceleration similar to that of gasoline powered cars. Therefore has the potential to be a power source for electrical vehicles. Aluminum\\/air battery vehicle

Shaohua Yang

2003-01-01

119

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

Microsoft Academic Search

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.

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

1980-01-01

120

Design Analysis of an Aluminum-Air Battery for Vehicle Operations. Transportation Systems Research.  

National Technical Information Service (NTIS)

The objective of the study reported was to perform a detailed configuration analysis of an aluminum-air battery, evaluate various automobile propulsion systems utilizing the Al-air battery, and estimate the performance and cost of vehicles incorporating t...

C. L. Hudson, D. J. Whisler, E. Behrin, J. D. Salisbury, R. L. Wood

1983-01-01

121

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.

122

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

123

Analysis of a novel mild air hybrid engine technology, RegenEBD, for buses and commercial vehicles  

Microsoft Academic Search

In this paper, a novel cost-effective mild air hybrid engine concept for buses and commercial vehicles, RegenEBD, is presented. This air hybrid technology is designed to convert kinetic energy into pneumatic energy of the compressed air stored in the air tank normally installed on such vehicles. The compressed air can then be used to drive an air starter to achieve

Cho-Yu Lee; Hua Zhao; Tom Ma

2012-01-01

124

Investigation of an energy harvesting small unmanned air vehicle  

NASA Astrophysics Data System (ADS)

The addition of energy harvesting is investigated to determine the benefits of its integration into a small unmanned air vehicle (UAV). Specifically, solar and piezoelectric energy harvesting techniques were selected and their basic functions analyzed. The initial investigation involved using a fundamental law of thermodynamics, entropy generation, to analyze the small UAV with and without energy harvesting. A notional mission was developed for the comparison that involved the aircraft performing a reconnaissance mission. The analysis showed that the UAV with energy harvesting generated less entropy. However, the UAV without energy harvesting outperformed the other UAV in total flight time at the target. The analysis further looked at future energy harvesting technologies and their effect on the energy harvesting UAV to conduct the mission. The results of the mission using the advanced solar technology showed that the effectiveness of the energy harvesting vehicle would increase. Designs for integrating energy harvesting into the small UAV system were also developed and tests were conducted to show how the energy harvesting designs would perform. It was demonstrated that the addition of the solar and piezoelectric devices would supply usable power for charging batteries and sensors and that it would be advantageous to implement them into a small UAV.

Magoteaux, Kyle C.; Sanders, Brian; Sodano, Henry A.

2008-03-01

125

DESIGN AND DEVELOPMENT OF A MICRO AIR VEHICLE (AV) CONCEPT: PROJECT BIDULE  

E-print Network

and the prop-wash can be kept to an acceptable level. Keywords: micro Unmanned Aerial Vehicles (UAVs), design, propeller effects, wind tunnel. Introduction The concept of micro-sized Unmanned Aerial Vehicles (UAVsDESIGN AND DEVELOPMENT OF A MICRO AIR VEHICLE (µµµµAV) CONCEPT: PROJECT BIDULE Mr T. Spoerry1 , Dr

Wong, K. C.

126

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

E-print Network

in the neighborhood of ground vehicles, civilians, as well as in poor weather likewise requires a host of innovations to this overall objective. I. INTRODUCTION The vital and increasing role of unmanned autonomous vehicles (UAVsVision-Based Control of Micro­Air­Vehicles: Progress and Problems In Estimation A. Kurdila, M

DeVore, Ronald

127

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

128

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

129

Seventh International Conference On High-Performance Marine Vehicles  

E-print Network

Pressure Ab Air Cushion Base Area 3 Vertical Displacement P0 Equilibrium Pressure ABBREVIATIONS ACV - Air, deck mounted air fans force air into the plenum and positive air pressure builds. When there is an excess of pressure in the cushion, air leaks out beneath the edges of the fore and aft skirts, Skolnick

Wood, Stephen L.

130

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

E-print Network

Q-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) sensor or camera is installed onboard the UAV for the purpose of detecting and classifying multiple

Ferrari, Silvia

131

Air quality and environmental impacts of alternative vehicle technologies in Ontario, Canada  

Microsoft Academic Search

This study is focused on the province-wide emissions in Ontario, Canada and urban air pollution in the city of Toronto. The life-cycle (LC) impacts of utilizing alternative fuels for transportation purposes is considered in terms of six major stressors for climate change, acidification and urban air quality. The vehicles considered are plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles (FCVs)

Ivan Kantor; Michael W. Fowler; Amirhossein Hajimiragha; Ali Elkamel

2010-01-01

132

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

133

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

Federal Register 2010, 2011, 2012, 2013

...FRL-9759-4] California State Motor Vehicle Pollution Control Standards...Waiver of Clean Air Act Preemption; California's 2010 Model...motor vehicle pollution control program...consistency of California's HD OBD...of the Clean Air Act, I...

2012-12-10

134

Travel Behavior and Older Vehicles: Implications for Air Quality and  

E-print Network

the programs to address key factors that reduce program effectiveness. Current programs are missing certain households that drive older vehicles a lot and have little impact on the vehicle replacement decision

Bertini, Robert L.

135

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

136

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

137

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

138

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

139

Aeroelastic analysis and optimization of membrane micro air vehicle wings  

NASA Astrophysics Data System (ADS)

Fixed-wing micro air vehicles are difficult to fly, due to their low Reynolds number, low aspect ratio nature: flow separation erodes wing efficiency, the wings are susceptible to rolling instabilities, wind gusts can be the same size as the flight speed, the range of stable center of gravity locations is very small, etc. Membrane aeroelasticity has been identified has a tenable method to alleviate these issues. These flexible wing structures are divided into two categories: load-alleviating or load-augmenting. This depends on the wing's topology, defined by a combination of stiff laminate composite members overlaid with a membrane sheet, similar to the venation patterns of insect wings. A series of well-validated variable-fidelity static aeroelastic models are developed to analyze the working mechanisms (cambering, washout) of membrane wing aerodynamics in terms of loads, wing deformation, and flow structures, for a small set of wing topologies. Two aeroelastic optimization schemes are then discussed. For a given wing topology, a series of numerical designed experiments utilize tailoring of laminate orientation and membrane pre-tension. Further generality can be obtained with aeroelastic topology optimization: locating an optimal distribution of laminate shells and membrane skin throughout the wing. Both optimization schemes consider several design metrics, optimal compromise designs, and experimental validation of superiority over baseline designs.

Stanford, Bret Kennedy

140

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

141

Development of Micro Air Vehicle Technology With In-Flight Adaptive-Wing Structure  

NASA Technical Reports Server (NTRS)

This is a final report on the research studies, "Development of Micro Air Vehicle Technology with In-Flight Adaptrive-Wing Structure". This project involved the development of variable-camber technology to achieve efficient design of micro air vehicles. Specifically, it focused on the following topics: 1) Low Reynolds number wind tunnel testing of cambered-plate wings. 2) Theoretical performance analysis of micro air vehicles. 3) Design of a variable-camber MAV actuated by micro servos. 4) Test flights of a variable-camber MAV.

Waszak, Martin R. (Technical Monitor); Shkarayev, Sergey; Null, William; Wagner, Matthew

2004-01-01

142

Space robot simulator vehicle  

NASA Technical Reports Server (NTRS)

A Space Robot Simulator Vehicle (SRSV) was constructed to model a free-flying robot capable of doing construction, manipulation and repair work in space. The SRSV is intended as a test bed for development of dynamic and static control methods for space robots. The vehicle is built around a two-foot-diameter air-cushion vehicle that carries batteries, power supplies, gas tanks, computer, reaction jets and radio equipment. It is fitted with one or two two-link manipulators, which may be of many possible designs, including flexible-link versions. Both the vehicle body and its first arm are nearly complete. Inverse dynamic control of the robot's manipulator has been successfully simulated using equations generated by the dynamic simulation package SDEXACT. In this mode, the position of the manipulator tip is controlled not by fixing the vehicle base through thruster operation, but by controlling the manipulator joint torques to achieve the desired tip motion, while allowing for the free motion of the vehicle base. One of the primary goals is to minimize use of the thrusters in favor of intelligent control of the manipulator. Ways to reduce the computational burden of control are described.

Cannon, R. H., Jr.; Alexander, H.

1985-01-01

143

Design and Research on Air Conditioning Control Network of Electric Vehicle Based on CAN-Bus  

Microsoft Academic Search

The design of the electric air-conditioning CANbus communication system makes a target of electric vehicles in order to form digital control network of a number of electronic control unit in electric vehicles, develop electric vehicles CAN (Controller Area Network)bus system, adopting communication protocol SAE J1939;the use of microprocessor STC12C5A60S2 complete design of CAN bus interface circuit; The digital simulation of

Fan Xin; Hu Chun

2010-01-01

144

Comparative Analysis of Aluminum-Air Battery Propulsion Systems for Passenger Vehicles.  

National Technical Information Service (NTIS)

Three electric propulsion systems using an aluminum-air battery were analyzed and compared to the internal-combustion-engine (ICE) vehicle. The analysis used projected battery characteristics extrapolated from laboratory measurements which were obtained i...

J. D. Salisbury, E. Behrin, M. K. Kong, D. J. Whisler

1980-01-01

145

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

146

Venus Atmospheric Maneuverable Platform (VAMP) — Air Vehicle Concept and Entry CONOPs  

NASA Astrophysics Data System (ADS)

This presentation discusses the continued development of the Northrop Grumman/L’GARDE team’s long-lived, maneuverable platform to explore the Venus upper atmosphere. It focuses on the air vehicle design and entry CONOPs and their interdependencies.

Sokol, D.; Lee, G.; Polidan, R.; Bolisay, L.; Barnes, N.

2014-06-01

147

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

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, Emergency Generator Enclosure, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

149

Fire resistant resilient foams. [for seat cushions  

NASA Technical Reports Server (NTRS)

Primary program objectives were the formulation, screening, optimization and characterization of open-cell, fire resistant, low-smoke emitting, thermally stable, resilient polyimide foams suitable for seat cushions in commercial aircraft and spacecraft. Secondary program objectives were to obtain maximum improvement of the tension, elongation and tear characteristics of the foams, while maintaining the resiliency, thermal stability, low smoke emission and other desirable attributes of these materials.

Gagliani, J.

1976-01-01

150

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

151

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.

152

Estimates of the cost and energy consumption of aluminum-air electric vehicles  

Microsoft Academic Search

Economic costs and primary energy consumption are estimated for general purpose electric vehicles using aluminum-air propulsion batteries within the time frame of the 1990's (earliest possible date of introduction). For an aluminum-air fuel economy of 36 tonne\\/km\\/kg-Al (optimized low-gallium alloys), a total refueling cost of 5.6 cents\\/km (1979$) was estimated for a 1.27 tonne vehicle. This is equivalent to $2

J. F. Cooper

1980-01-01

153

Significant Fuel Savings and Emission Reductions by Improving Vehicle Air Conditioning  

Microsoft Academic Search

Vehicle air conditioning (A\\/C) systems significantly increase the fuel use and tailpipe emissions of automobiles. In addition, emissions of the A\\/C refrigerant are greenhouse gases. In 2002, the National Renewable Energy Laboratory (NREL) determined the U.S. national and state-by-state fuel use impact of air conditioning in light duty vehicles. In 2003, we expanded the analysis to cover Europe and Japan.

John P. Rugh; Valerie Hovland; Stephen O. Andersen

154

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

155

An analysis of aluminum-air battery propulsion systems for passenger vehicles  

Microsoft Academic Search

The performance characteristics of three electric-propulsion systems based on the Al-air battery were analyzed and compared to the internal combustion engine (ICE). In this comparison, the engine and fuel systems of a current five-passenger vehicle were conceptually replaced by three Al-air systems: (1) an Al-air battery-only system, (2) an Al-air battery combined with a nickel-zinc secondary battery for power leveling,

J. D. Salisbury; E. Behrin

1980-01-01

156

Vector field path following for small unmanned air vehicles  

Microsoft Academic Search

This paper presents a new method for unmanned aerial vehicle path following using vector fields to represent desired ground track headings to direct the vehicle onto the desired path. The key feature of this approach is that ground track heading error and lateral following error approach zero asymptotically even in the presence of constant wind disturbances. Methods for following straight-line

Derek R. Nelson; D. B. Barber; T. W. McLain; R. W. Beard

2006-01-01

157

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

Federal Register 2010, 2011, 2012, 2013

...the motor vehicle air conditioning end-use within the refrigeration and air conditioning sector, to be acceptable subject to...sectors (subpart G of 40 CFR part 82). These sectors--refrigeration and air conditioning; foam blowing; cleaning...

2012-03-26

158

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

159

Wheelchair cushions for persons with spinal cord injury: an update.  

PubMed

Occupational therapists frequently prescribe wheelchair cushions to reduce the risk of pressure sores in patients with spinal cord injury. In an earlier study (Garber, 1985b), Roho cushions were prescribed for the greatest number of subjects studied. The present study of 197 subjects updates these data and describes current prescription patterns, the use of cushions over time, satisfaction with prescribed cushions, and the occurrence of pressure sores with prescribed cushions. The study shows that the Jay cushion was prescribed most frequently for the current subjects, although it was not recommended for all persons with spinal cord injury. In the second phase of the present study, involving 30 subjects, 30% of the subjects discontinued use of the prescribed cushion. Skin breakdown and the discovery of alternative solutions were given as primary reasons. There was no significant difference in the incidence of pressure sores between subjects who continued to use their prescribed cushions and those who did not. This research supports the conclusion of earlier studies that no one wheelchair cushion is universally effective for all persons and that individual evaluation and routine reassessment are essential in reducing the occurrence of pressure sores. PMID:2063944

Garber, S L; Dyerly, L R

1991-06-01

160

The cost of crop damage caused by ozone air pollution from motor vehicles  

SciTech Connect

The effects of ozone air pollution on the agricultural sector are an important environmental challenge facing policy makers. Most studies of the economic impact of air pollution on agriculture have found that a 25% reduction in ambient ozone would provide benefits of at least $1--2 billion annually in the United States. This paper extends existing research by estimating the benefits of a reduction in emissions from a major source of ozone formation: motor-vehicle emissions. An agricultural production model is combined with an analysis of motor-vehicle emissions and air quality to estimate the impacts of emissions from six different motor-vehicle classes, at both the regional and national level. The benefits to the agricultural sector from completely eliminating ozone precursor emissions from motor vehicles ranges between $3.5 and $6.1 billion annually.

Murphy, J.J. (Univ. of Arizona, Tucson, AZ (United States). Economic Science Lab. Univ. of California, Davis, CA (United States). Dept. of Agricultural and Resource Economics); Delucchi, M.A. (Univ. of California, Davis, CA (United States). Inst. of Transportation Studies); McCubbin, D.R. (Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Economics); Kim, H.J. (Environmental Protection Agency, Washington, DC (United States). Environmental Economics Div.)

1999-04-01

161

A diagnostic system for air brakes in commercial vehicles  

E-print Network

, cranes, conveyors, agitators, etc.), paint spraying, marine applications, pneumatic actuators, etc. [29]. One of the major applications of compressed air in the field of transportation has been in the development of the air brake system. In the United..., cranes, conveyors, agitators, etc.), paint spraying, marine applications, pneumatic actuators, etc. [29]. One of the major applications of compressed air in the field of transportation has been in the development of the air brake system. In the United...

Coimbatore Subramanian, Shankar Ram

2007-09-17

162

The development of aluminum-air batteries for application in electric vehicles  

Microsoft Academic Search

The recently concluded program, jointly funded by ELTECH Research Corporation and the Department of Energy, focused upon the development of an aluminum-air battery system for electric vehicle applications. The operation of the aluminum-air battery involves the dissolution of aluminum to produce a current and aluminate. Initially the objectives were to evaluate and optimize the battery design that was developed prior

E. J. Rudd; S. Lott

1990-01-01

163

Separation Flight Tests of a Small Unmanned Air Vehicle from a C-130 Transport Aircraft  

Microsoft Academic Search

Unmanned Air Vehicles (UAVs) are increasingly being considered for various roles in the civilian and military communities. Various launch methods have been explored and have been mostly ground based. The desire to investigate the feasibility of launching a UAV from a larger surrogate air platform existed, but had not been explored. As part of a concept demonstration program, NAVAIR's Test

David W. Roberts; Aaron D. Judy

164

A hardware in the loop simulation platform for vision-based control of unmanned air vehicles  

E-print Network

A hardware in the loop simulation platform for vision-based control of unmanned air vehicles N a r t i c l e i n f o Keywords: Hardware in the loop simulation Vision-based control Unmanned air, such as sensor noise and actuator lag. For these reasons, hardware in the loop simulation (HILS) platforms

Dixon, Warren

165

Numerical simulation of engine cooling air flow of a road vehicle  

NASA Astrophysics Data System (ADS)

A modeling method for a heat exchanger is presented to predict engine cooling air flow rate. The comparison between calculations and experiments confirms accuracy of the modeling method. A modeling of vehicle body configuration is also discussed. It is found that precise modeling of engine room outlet configuration is important to improve estimation accuracy of engine cooling air flow rate. By taking into account these modeling methods, it is expected that the under floor flow field of a vehicle will be estimated accurately. This enables the study on flow interaction between engine cooling air flow and under floor flow numerically, which has been difficult to obtain physical image experimentally.

Ukita, Tetsuji; Kataoka, Takuya; China, Hiroshi

1993-09-01

166

Design analysis of an aluminum-air battery for vehicle operations. Transportation systems research  

Microsoft Academic Search

The objective of the study reported was to perform a detailed configuration analysis of an aluminum-air battery, evaluate various automobile propulsion systems utilizing the Al-air battery, and estimate the performance and cost of vehicles incorporating these propulsion systems. A preliminary engineering design is performed. A physical model and a cell-performance model of a conceptual mass-produced Al-air battery were constructed and

E. Behrin; R. L. Wood; J. D. Salisbury; D. J. Whisler; C. L. Hudson

1983-01-01

167

Environmental impacts associated with the aluminum-air battery electric vehicle fuel cycle  

Microsoft Academic Search

The aluminum-air battery concept is discussed, and a scenario is developed which forecasts ten million aluminum-air electric vehicles in the US by the year 2000. An estimation is made regarding the consumption of natural resources and generation of wastes due to the aluminum-air battery's fuel cycle and to the increased demand on the US aluminum industry because of the scenario.

K. J. E

1982-01-01

168

A comparison of metal-air batteries for electric vehicle propulsion  

Microsoft Academic Search

A comparison is made among four metal-air systems being considered for future use in commuter electric vehicles. The anode materials are lithium, aluminum, zinc and iron. The lithium-air system is still in an early stage of development. A proposed mechanically rechargeable aluminum-air system is potentially capable of superior performance but its relative cost of ownership and operation is expected to

W. A. Bryant; E. S. Buzzelli

1979-01-01

169

A preliminary study of the air data sensing problem on a re-entry vehicle  

NASA Astrophysics Data System (ADS)

A brief review of different measurement techniques for speed, pressure, and temperature on a re-entry vehicle is given in order to evaluate their applicability and limitations to the design of an air data system. A pressure-sensors based air data system is then assumed and an engineering aerodynamic model is used to investigate the influence of the measurement errors on the relevant air data parameters necessary for light guidance and control.

Hettena, E.

1995-03-01

170

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

171

Suspension element for the exhaust system of a motor vehicle engine  

SciTech Connect

This patent describes a motor vehicle having a floor with an exhaust system extending therebeneath, elastic air-filled suspension means for suspending the exhaust system from the floor while attenuating vibrations generated by the exhaust system prior to their transmission to the floor. The means comprises a pair of elastic rings that are linked together and adapted to be connected to the floor and exhaust system respectively, and an air-filled elastic sphere arranged between the rings at their linkage so as to provide an air cushion therebetween.

Schad, K.

1987-01-06

172

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

173

Modeling and analysis of an articulated winged micro air vehicle for gust mitigation  

NASA Astrophysics Data System (ADS)

Articulated micro air vehicles are a class of micro air vehicles comprised of a main center body attached to outer wings on both sides. As in the case of a single rigid micro air vehicle, the center body and the attached bodies in the articulated case are all responsible for the generation of aerodynamic forces and moments during flight resulting in a multibody system. While many approaches have been taken in the literature to model the system of equations resulting from such a complicated multibody system, this dissertation presents an approach based on a Newton-Euler multibody dynamics formulation where the multiple bodies are attached together with suitable joints. The number and type of joints determines the level of articulation and total degree of freedom for the entire system. Unlike most articulated air vehicle model formulations available in the literature, the final model formulation presented in this work provides joint force and moment data acting on the articulated MAV during flight. This feature allows such information to be available during the vehicle design and development stage where appropriate spring and dampers for the system are selected based on mission requirements. Experimental validation of the proposed mathematical model using experimental flight test data obtained from UAHuntsville's Autonomous Tracking and Optical Measurements laboratory allowed the comparison of the flight test results and model simulations. Analytical investigation of the gust alleviation properties of the articulated 8 degree-of-freedom micro air vehicle model was carried out using simulations with varying crosswind gust magnitudes and shows that the passive articulation in micro air vehicles increases their robustness to gusts when suitable joint parameters are selected.

Oduyela, Adetunji Y.

174

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

175

Air Force's Evolved Expendable Launch Vehicle Competitive Procurement.  

National Technical Information Service (NTIS)

DOD's EELV program is the primary provider of launch vehicles and services for U.S. military and intelligence satellites. The most recent independent cost estimate projects the program will cost about $70 billion through 2030. From 2006 to 2013, the progr...

2014-01-01

176

Planning and control for Unmanned Air Vehicle formation flight  

Microsoft Academic Search

We present a set of algorithmic solutions for a fleet of unmanned aerial vehicles evolving along in tight coordination in a constrained environment. The mission to achieve is defined by an ordered sequence of waypoints and a set of constraints to satisfy. The algorithms allow the determination of the geometric configuration of the UAVs, of the trajectories to switch from

Gautier Hattenberger; Rachid Alami; Simon Lacroix

2006-01-01

177

California's Zero Emission Vehicle Program Cleaner air needed  

E-print Network

Stage 1 smog alerts each year in the Los Angeles area. Major efforts to reduce air pollution, mainly smog alerts in Los Angeles never exceeded 14 in one year. There were no Stage 1 alerts in 1999 or 2000 that fail to meet federal or state air quality standards. ? Roughly 50% of smog-forming pollutants still

Gille, Sarah T.

178

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

179

Comparisons of rocket and air-breathing vehicle concepts for earth-to-orbit transportarion  

NASA Astrophysics Data System (ADS)

To illustrate that there is ample room for improvement in earth-to-orbit reliability, transportation cost and environmental cleanliness, some future European launch vehicle concepts are presented. Varying assumptions of technology level and operational strategy offer a wide range of system/subsystem options for consideration. Specific examples cited include: the advanced reusable single-stage VTOL all-rocket vehicles, the all-liquid hydrogen-oxygen variants of Ariane 5, and the advanced one-and-a-half-stage horizontal take-off air-breathing vehicles.

Dorrington, G. E.

1990-07-01

180

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.

181

AIR QUALITY IMPACTS OF ELECTRIC VEHICLE ADOPTION IN TEXAS  

E-print Network

improving regional air quality, increasing energy security, and taking advantage of inexpensive solar power conventional passenger cars in Texas, after recognizing the emissions and energy impacts of battery provision

Kockelman, Kara M.

182

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

Federal Register 2010, 2011, 2012, 2013

...3-tetrafluoroprop-1-ene), a substitute for ozone- depleting substances (ODSs) in the motor vehicle air conditioning end- use within the refrigeration and air conditioning sector, as acceptable subject to use conditions under the EPA's Significant New Alternatives...

2012-03-23

183

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

184

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

185

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 airbreathing 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 ramjet/scramjets, 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 demonstrate 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 development 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.

2002-01-01

186

Improving the aluminum-air battery system for use in electrical vehicles  

NASA Astrophysics Data System (ADS)

The objectives of this study include improvement of the efficiency of the aluminum/air battery system and demonstration of its ability for vehicle applications. The aluminum/air battery system can generate enough energy and power for driving ranges and acceleration similar to that of gasoline powered cars. Therefore has the potential to be a power source for electrical vehicles. Aluminum/air battery vehicle life cycle analysis was conducted and compared to that of lead/acid and nickel-metal hydride vehicles. Only the aluminum/air vehicles can be projected to have a travel range comparable to that of internal combustion engine vehicles (ICE). From this analysis, an aluminum/air vehicle is a promising candidate compared to ICE vehicles in terms of travel range, purchase price, fuel cost, and life cycle cost. We have chosen two grades of Al alloys (Al alloy 1350, 99.5% and Al alloy 1199, 99.99%) in our study. Only Al 1199 was studied extensively using Na 2SnO3 as an electrolyte additive. We then varied concentration and temperature, and determined the effects on the parasitic (corrosion) current density and open circuit potential. We also determined cell performance and selectivity curves. To optimize the performance of the cell based on our experiments, the recommended operating conditions are: 3--4 N NaOH, about 55°C, and a current density of 150--300 mA/cm2. We have modeled the cell performance using the equations we developed. The model prediction of cell performance shows good agreement with experimental data. For better cell performance, our model studies suggest use of higher electrolyte flow rate, smaller cell gap, higher conductivity and lower parasitic current density. We have analyzed the secondary current density distributions in a two plane, parallel Al/air cell and a wedge-type Al/air cell. The activity of the cathode has a large effect on the local current density. With increases in the cell gap, the local current density increases, but the increase is not as significant as the increase in the current density away from the entrance. By extending the cathode below the anode, the high local current density can be reduced.

Yang, Shaohua

187

Complete endocardial cushion defects in pregnancy: a case report  

PubMed Central

Introduction Complete endocardial cushion defect is a congenital heart disease characterized by a variable deficiency of the atrioventricular area in the developing heart. The mortality rate for an unrepaired endocardial cushion defect in pregnancy and the postpartum period is high. Case presentation We present a rare case of a pregnant woman with complete endocardial cushion defect. A 20-year-old Chinese woman with unrepaired complete endocardial cushion defect delivered a premature male baby at 33 weeks and six days of pregnancy in our hospital. The baby had a normal human karyotype and a birth defect of hypospadias deformity. Our patient died from heart failure 10 minutes after delivery. She had severe pulmonary hypertension and suspected trisomy 21. Conclusion Our experience further emphasizes the necessity of prenatal screening for congenital heart defects and of prompt surgical correction for endocardial cushion defects during infancy. Mortality for endocardial cushion defect during pregnancy and the postpartum period is high and women with complete endocardial cushion defect should avoid pregnancy, especially those women who cannot intellectually judge their risks. PMID:24607268

2014-01-01

188

HIGH SPEED, IN-FLIGHT STRUCTURAL HEALTH MONITORING SYSTEM FOR MEDIUM ALTITUDE LONG ENDURANCE UNMANNED AIR VEHICLE  

E-print Network

UNMANNED AIR VEHICLE I. Kressel1 , J. Balter1 , N. Mashiach2 , I. Sovran3 , O. Shapira4 , N.Y. Shemesh4 B Endurance (MALE) Unmanned Aerial Vehicle (UAV).A total of 54 FBG sensors were embedded on the wing and tail The increasing value of modern Unmanned Aerial Vehicles (UAVs), together with their high usage under variety

Paris-Sud XI, Université de

189

Design and analysis of aluminum\\/air battery system for electric vehicles  

Microsoft Academic Search

Aluminum (Al)\\/air batteries have the potential to be used to produce power to operate cars and other vehicles. These batteries might be important on a long-term interim basis as the world passes through the transition from gasoline cars to hydrogen fuel cell cars. The Al\\/air battery system can generate enough energy and power for driving ranges and acceleration similar to

Shaohua Yang; Harold Knickle

2002-01-01

190

Development of the aluminum-air battery for electric vehicle applications  

Microsoft Academic Search

Current progress is reported concerning the development of hardware for the aluminum-air electric vehicle battery. The polarization curves of large-scale aluminum-air cells (0.1-m² anodes) have been replicated in rapidly-refuelable cells of subscale size (167-cm²) which were constructed for stacking into multicell modules. Solution-side current colllection by a structure which makes point- or line contacts at the aluminum\\/electrolyte interface is described.

J. F. Cooper; R. V. Homsy

1981-01-01

191

Trajectory Planning For Coordinated Rendezvous Of Unmanned Air Vehicles  

Microsoft Academic Search

A trajectory generation strategy that facilitatesthe coordination of multiple unmanned air vehiclesis developed. Of particular interest is the planning ofthreat-avoiding trajectories that result in the simultaneousarrival of multiple UAVs at their targets. Inthis approach, paths to the target are modeled usingthe physical analogy of a chain. A unique strengthof the planning approach is the ability to specify oralter the pathlength

Timothy W. Mclain; Randal W. Beard

2000-01-01

192

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

193

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

194

Design and analysis of aluminum/air battery system for electric vehicles  

NASA Astrophysics Data System (ADS)

Aluminum (Al)/air batteries have the potential to be used to produce power to operate cars and other vehicles. These batteries might be important on a long-term interim basis as the world passes through the transition from gasoline cars to hydrogen fuel cell cars. The Al/air battery system can generate enough energy and power for driving ranges and acceleration similar to gasoline powered cars. From our design analysis, it can be seen that the cost of aluminum as an anode can be as low as US 1.1/kg as long as the reaction product is recycled. The total fuel efficiency during the cycle process in Al/air electric vehicles (EVs) can be 15% (present stage) or 20% (projected) comparable to that of internal combustion engine vehicles (ICEs) (13%). The design battery energy density is 1300 Wh/kg (present) or 2000 Wh/kg (projected). The cost of battery system chosen to evaluate is US 30/kW (present) or US$ 29/kW (projected). Al/air EVs life-cycle analysis was conducted and compared to lead/acid and nickel metal hydride (NiMH) EVs. Only the Al/air EVs can be projected to have a travel range comparable to ICEs. From this analysis, Al/air EVs are the most promising candidates compared to ICEs in terms of travel range, purchase price, fuel cost, and life-cycle cost.

Yang, Shaohua; Knickle, Harold

195

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

196

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

197

CFD based aerodynamic modeling to study flight dynamics of a flapping wing micro air vehicle  

NASA Astrophysics Data System (ADS)

The demand for small unmanned air vehicles, commonly termed micro air vehicles or MAV's, is rapidly increasing. Driven by applications ranging from civil search-and-rescue missions to military surveillance missions, there is a rising level of interest and investment in better vehicle designs, and miniaturized components are enabling many rapid advances. The need to better understand fundamental aspects of flight for small vehicles has spawned a surge in high quality research in the area of micro air vehicles. These aircraft have a set of constraints which are, in many ways, considerably different from that of traditional aircraft and are often best addressed by a multidisciplinary approach. Fast-response non-linear controls, nano-structures, integrated propulsion and lift mechanisms, highly flexible structures, and low Reynolds aerodynamics are just a few of the important considerations which may be combined in the execution of MAV research. The main objective of this thesis is to derive a consistent nonlinear dynamic model to study the flight dynamics of micro air vehicles with a reasonably accurate representation of aerodynamic forces and moments. The research is divided into two sections. In the first section, derivation of the nonlinear dynamics of flapping wing micro air vehicles is presented. The flapping wing micro air vehicle (MAV) used in this research is modeled as a system of three rigid bodies: a body and two wings. The design is based on an insect called Drosophila Melanogaster, commonly known as fruit-fly. The mass and inertial effects of the wing on the body are neglected for the present work. The nonlinear dynamics is simulated with the aerodynamic data published in the open literature. The flapping frequency is used as the control input. Simulations are run for different cases of wing positions and the chosen parameters are studied for boundedness. Results show a qualitative inconsistency in boundedness for some cases, and demand a better aerodynamic data. The second part of research involves preliminary work required to generate new aerodynamic data for the nonlinear model. First, a computational mesh is created over a 2-D wing section of the MAV model. A finite volume based computational flow solver is used to test different flapping trajectories of the wing section. Finally, a parametric study of the results obtained from the tests is performed.

Rege, Alok Ashok

198

Estimates of the cost and energy consumption of aluminum-air electric vehicles  

NASA Astrophysics Data System (ADS)

Economic costs and primary energy consumption are estimated for general purpose electric vehicles using aluminum-air propulsion batteries within the time frame of the 1990's (earliest possible date of introduction). For an aluminum-air fuel economy of 36 tonne/km/kg-Al (optimized low-gallium alloys), a total refueling cost of 5.6 cents/km (1979$) was estimated for a 1.27 tonne vehicle. This is equivalent to $2 to 3/gal for automobiles of the same weight with fuel economies of 13.5 to 19.3 tonne-km/liter. The total primary energy consumption was estimated to be 1.3 to 1.7 kWh/km (coal) for the electric vehicle, which corresponds roughly to the energy cost of the automobiles using liquid fuels synthesized from coal. The energy consumption is 30 to 70 percent greater than the reference automobile using petroleum-derived gasoline.

Cooper, J. F.

1980-11-01

199

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

200

Radar Cross Section measurements of small Unmanned Air Vehicle Systems in non-cooperative field environments  

Microsoft Academic Search

The growing use of unmanned air vehicle systems (UAVS) is drawing increased interest in their radar signature to search and track radars. Because it is not always possible to transport UAVS to radar cross section (RCS) measurement facilities, a portable RCS measurement system has been developed and demonstrated in non-cooperative field environments. This paper presents the portable RCS measurement system

A. Bati; D. Hilliard

2009-01-01

201

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

202

AN INTEGER PROGRAMMING MODEL FOR ASSIGNING UNMANNED AIR VEHICLES TO TASKS  

Microsoft Academic Search

We consider a team of unmanned air vehicles (UAVs), deployed to carry out tasks such as searching for, classifying, attacking, and performing battle damage assessment of enemy targets. In some missions, it may be advantageous for the UAVs to form sub-teams to leverage their efforts and cooperatively handle single enemy targets. Within a sub-team, each UAV would be responsible for

Michael J. Hennebry; Ahmed Kamel

203

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

E-print Network

of a swarm of air vehicles whose mission is to search for, classify, attack, and perform battle damage damage assessment. In this paper we describe a time-phased network optimization model designed to produce assessment, is considered. It is assumed that the target field information is communicated to all

Nygard, Kendall E.

204

Landing an Unmanned Air Vehicle: Vision Based Motion Estimation and Nonlinear Control  

Microsoft Academic Search

In this paper, we use computer vision as a feedback sensor in a control loop for landing an unmanned air vehicle (UAV) on a landing pad. The vision problem we address here is then a special case of the classic ego-motion estimation problem since all feature points lie on a planar surface (the landing pad). We study together the discrete

Omid Shakernia; Yi Ma; T. John; Koo Shankar Sastry

1999-01-01

205

Real-Time Dynamic Planning to Maintain Network Connectivity in a Team of Unmanned Air Vehicles  

E-print Network

1 Real-Time Dynamic Planning to Maintain Network Connectivity in a Team of Unmanned Air Vehicles of unmanned systems will span all operational domains and become increasingly important in many applications. Teams of unmanned systems can be composed of agents with different capabilities, and must often operate

How, Jonathan P.

206

Trajectory tracking for unmanned air vehicles with velocity and heading rate constraints  

Microsoft Academic Search

This paper considers the problem of constrained nonlinear trajectory tracking control for unmanned air vehicles (UAVs). We assume that the UAV is equipped with longitudinal and lateral autopilots which reduces the 12-state model to a six-state model with altitude, heading, and velocity command inputs. One of the novel features of our approach is that we explicitly account for heading rate

Wei Ren; Randal W. Beard

2004-01-01

207

Visual servoing of an autonomous Micro Air Vehicle for ground object tracking  

Microsoft Academic Search

This paper describes an object tracking system using an autonomous micro air vehicle (MAV) and demonstrate its potential use for civilian purposes. The vision-based control system relies on a color and feature based vision algorithm for target detection and tracking, Kalman filters for relative pose estimation, and a nonlinear controller for MAV stabilization and guidance. The vision algorithm relies on

Syaril Azrad; Farid Kendoul; Dwi Perbrianti; Kenzo Nonami

2009-01-01

208

A hardware in the loop simulation platform for vision-based control of unmanned air vehicles  

Microsoft Academic Search

Design and testing of control algorithms for unmanned air vehicles (UAV’s) is difficult due to the delicate and expensive nature of UAV systems, the risk of damage to property during testing, and government regulations. This necessitates extensive simulation of controllers to ensure stability and performance. However, simulations cannot capture all aspects of a flight control, such as sensor noise and

N. R. Gans; W. E. Dixon; R. Lind; A. Kurdila

2009-01-01

209

Image Multiresolution Discriminant Analysis for Vision-Guided Stability of Micro Air Vehicles  

Microsoft Academic Search

Recently, we have successfully implemented and tested a vision based horizon-tracking algorithm for flight stability and autonomy in Micro Air Vehicles (MAVs). Occa- sionally, this algorithm fails in scenarios where the underlying Gaussian assumption for the sky and ground appearances is not appropriate. To improve its performance, especially in the presence of video noise, we consider a novel image analy-

Sinisa Todorovic; Michael C. Nechyba; Antonio A. Arroyo

210

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

Microsoft Academic Search

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 105 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

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

2011-01-01

211

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

212

The Micro Craft iSTAR Micro Air Vehicle: Control System Design and Testing  

E-print Network

at the American Helicopter Society 57th Annual forum, Washington, DC, May 9-11, 2001. Copyright 2001 by the American Helicopter Society International, Inc. All rights reserved. #12;Introduction The Micro Craft Inc.1 iSTAR is a Vertical Take-Off and Landing air vehicle (Figure 1) utilizing ducted fan technology

Rotkowitz, Michael C.

213

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

Microsoft Academic Search

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

Felipe Bohorquez

2007-01-01

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

Coordinated Target Assignment and Intercept for Unmanned Air Vehicles  

Microsoft Academic Search

Abstract: This paper presents an end-to-end solution to thebattlefield scenario where M unmanned air vehiclesare assigned to strike N known targets, in the presenceof dynamic threats. The problem is decomposedinto the subproblems of (1) cooperative target assignment,(2) coordinated UAV intercept, (3) path planning,and (4) feasible trajectory generation. The designtechnique is based on a hierarchical approach tocoordinated control. Detailed simulation results

Randal W. Beard; Timothy W. McLaint; Michael A. Goodrich

2002-01-01

216

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

217

21 CFR 874.1100 - Earphone cushion for audiometric testing.  

Code of Federal Regulations, 2013 CFR

...cushion for audiometric testing is a device that is used to cover an audiometer earphone during audiometric testing to provide an acoustic coupling (sound connection path) between the audiometer earphone and the patient's ear. (b) Classification....

2013-04-01

218

21 CFR 874.1100 - Earphone cushion for audiometric testing.  

Code of Federal Regulations, 2010 CFR

...cushion for audiometric testing is a device that is used to cover an audiometer earphone during audiometric testing to provide an acoustic coupling (sound connection path) between the audiometer earphone and the patient's ear. (b) Classification....

2010-04-01

219

21 CFR 874.1100 - Earphone cushion for audiometric testing.  

Code of Federal Regulations, 2011 CFR

...cushion for audiometric testing is a device that is used to cover an audiometer earphone during audiometric testing to provide an acoustic coupling (sound connection path) between the audiometer earphone and the patient's ear. (b) Classification....

2011-04-01

220

Design analysis of an aluminum-air battery for vehicle operations. Transportation systems research  

SciTech Connect

The objective of the study reported was to perform a detailed configuration analysis of an aluminum-air battery, evaluate various automobile propulsion systems utilizing the Al-air battery, and estimate the performance and cost of vehicles incorporating these propulsion systems. A preliminary engineering design is performed. A physical model and a cell-performance model of a conceptual mass-produced Al-air battery were constructed and work together to characterize the battery system. The physical battery model is based on a specific battery design concept and defines the mass and volume of a complete Al-air battery system. The cell-performance model simulates the electrical and electrochemical characteristics of the battery. The physical model and two versions of the cell-performance model - near-term and optimistic - were used in a vehicle-conversion analysis to evaluate three automotive propulsion systems - Al-air battery only, Al-air battery/secondary battery, and Al-air battery/flywheel. (LEW)

Behrin, E.; Wood, R.L.; Salisbury, J.D.; Whisler, D.J.; Hudson, C.L.

1983-03-18

221

Intersociety Advanced Marine Vehicles Conference and Exhibit, Arlington, VA, June 5-7, 1989, Technical Papers  

NASA Astrophysics Data System (ADS)

The present conference on advanced marine vehicles discusses advancements in surface-effect ship (SES) technologies, small waterplane-area twin-hull (SWATH) ship operations, advanced marine vehicle concepts, ocean systems and subsurface vehicles, air-cushion vehicle (ACV) concepts, seaplane technologies, advanced hull hydrodynamics, wing-in-ground effect (WIGE) aircraft, competition-craft aerodynamics, and marine propulsion. Attention is given to military applications of the 'NES 200' SES platform, experiences over 16 years of SWATH ship operations, hydrofoil catamarans for military and civilian applications, SES passenger ferries for the N.Y.C. metropolitan area, advanced submarine concepts, parametric studies in SWATH ship design, ACV experience in Antarctica, the CL-215 seaplane, large-scale WIGE vehicles, an ocean spacecraft-launch facility, an ACV Arctic icebreaker, and 'marinizing' methods for gas turbine engines.

222

Performance Validation Approach for the GTX Air-Breathing Launch Vehicle  

NASA Technical Reports Server (NTRS)

The primary objective of the GTX effort is to determine whether or not air-breathing propulsion can enable a launch vehicle to achieve orbit in a single stage. Structural weight, vehicle aerodynamics, and propulsion performance must be accurately known over the entire flight trajectory in order to make a credible assessment. Structural, aerodynamic, and propulsion parameters are strongly interdependent, which necessitates a system approach to design, evaluation, and optimization of a single-stage-to-orbit concept. The GTX reference vehicle serves this purpose, by allowing design, development, and validation of components and subsystems in a system context. The reference vehicle configuration (including propulsion) was carefully chosen so as to provide high potential for structural and volumetric efficiency, and to allow the high specific impulse of air-breathing propulsion cycles to be exploited. Minor evolution of the configuration has occurred as analytical and experimental results have become available. With this development process comes increasing validation of the weight and performance levels used in system performance determination. This paper presents an overview of the GTX reference vehicle and the approach to its performance validation. Subscale test rigs and numerical studies used to develop and validate component performance levels and unit structural weights are outlined. The sensitivity of the equivalent, effective specific impulse to key propulsion component efficiencies is presented. The role of flight demonstration in development and validation is discussed.

Trefny, Charles J.; Roche, Joseph M.

2002-01-01

223

A regional review of air medical transports for fatal motor vehicle crashes.  

PubMed

This article presents study results from an assessment of the performance of the air medical (and advanced life support) components of the EMS system in response to fatal motor vehicle crashes. Results are presented for one of Massachusetts' five EMS regions, including the finding that air medical transports are involved in 20% of the fatal crashes for the region and transport 11% of the involved individuals. Although the study focused on air medical utilization, it also identified issues related to the future implementation of motor vehicle automatic crash notification (ACN) and telematics that could relay crash severity data from onboard computers (e.g., event data recorders) to auto manufacturers' help centers or state emergency call centers. This technology will place new demands on state EMS systems. To meet the challenges posed by these technological changes, states will need to assess the type and number of EMS services required to respond to ACN motor vehicle crashes and develop methods to determine what level of service to deploy based on the information relayed from the vehicles. An initial step in this evaluation process is to determine the current use of EMS resources to place planned system changes and demand into context. PMID:11184482

Garthe, E A; Mango, N K; Prenney, B

2000-01-01

224

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

225

Multi-method investigation of cushion peatlands (  

NASA Astrophysics Data System (ADS)

This study presents a multi-method and multi-proxy approach for palaeonvironmental investigations in the western andean cordillera of southern Peru (Lucanas province, 14° S) using cushion peatlands as terrestrial geoarchives. The region stretching between the Altiplano and the Peruvian desert in the lowland shares a long term settlement history, in which local cultures adapted to climate change in many different ways. Being one of the most outstanding human remains, the abri below Cerro Llamoca, 4.450 m a.s.l. in the uppermost ranges of the Llamoca peatland catchment area further reveals an occupation history of almost 10.000 years, as revealed by latest archaeological investigations. In remote and highly elevated regions such as the central Andes, cushion peatlands basically represent the only high resolution terrestrial archives suitable for geoarchaeological and palaeoenvironmental studies. Characterized by high accumulation rates, they ideally document environmental changes, particularly at small time intervals. Within the multidisciplinary project 'Andean Transect - Climate Sensitivity of pre-Columbian Man-Environment-Systems' several sediment cores with depths up to 11.5 m b.s. were recovered from the Llamoca peatland. Based on almost 100 AMS 14C-datings they provide a chronology of 8000 years and, thus, offer profound insights into climatic and environmental changes in the study area. While nearly homogeneous peat layers record stable environmental conditions, the heterogeneous granulometric composition of intercalated sediment layers documents several periods of intense geomorphodynamic activity. Due to high resolution geochemical analyses of peat layers (1 cm interval; humification degree, CNS measurements, XRF-scanning), the existence of slight and short-term trends of landscape development during these phases can be identified. Additional pollen, charred particles and plant macrofossil analyses confirm these findings and help reconstructing local vegetation history. High-resolution digital elevation models derived from terrestrial laser scanning (TLS) provide important input data for geomorphologic analyses on current geomorphic processes that can be transferred to former times. Detailed subsurface information obtained by geophysics (electrical resistivity tomography ERT) helped identify the most suitable sampling sites. Information about peat thickness, stratigraphy and depth to bedrock was combined with topographical elevation data, chronometrical outcomes and palaeoenvironmental parameters to generate subsurface models of the study site. The findings allow reconstructing and visualizing the ancient landscape and the stages of peat development, which coincide with pre-Columbian cultural eras.

Forbriger, M.; Schittek, K.; Höfle, B.; Siart, C.; Eitel, B.

2012-04-01

226

Topics in the structural dynamics and control of an articulated micro air vehicle  

NASA Astrophysics Data System (ADS)

This work presents a methodology to determine of accurate computer models of articulated micro air vehicles. Prior to this work, much of the innovation in design of a micro air vehicle was based on empirical data. This emphasis on empirical data necessitates a time intensive iterative process where a design is built and tested, then modifications are made and the process starts anew. This work looks to alleviate some of the load of this iteration by producing accurate models that can be inserted into the process at greatly reduced cost in terms of time. The modeling is accomplished by the application of Lagrange's equations to create a set of equations that incorporate both the rigid and flexible degrees of freedom associated with the materials that Micro Air Vehicles (MAVs) employ. These equations of motion also include the generalized forces that result from the body forces due to gravity and external forces acting as a result of the interaction between the structure and the air through which it passes. These equations are formulated in a manner that accomplishes the above while allowing for the reconfiguration of the system. The equations of motion are then transformed into a form amenable for use in the solution of an optimal control problem.

Regisford, Sean James Sidney

227

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

228

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

229

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

230

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

231

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

232

Evaluation of alternatives for HFC-134a refrigerant in motor vehicle air conditioning  

SciTech Connect

HFC (hydrofluorocarbon)-134a is currently used as the refrigerant in motor vehicle air conditioners. The EPA`s (Environmental Protection Agency`s) NRMRL (National Risk Management Research Laboratory) has evaluated lower global warming alternatives for HFC-134a in motor vehicle air conditioning. Alternative technologies were evaluated. Four pure chemicals and one azeotropic mixture were identified and evaluated as alternative refrigerants for conventional systems, but were found to be unsuitable. The four pure chemicals were HFC-227ca, HFC-227ea, HFC-245cb, and HFE (hydrofluoroether)-143a. The azeotropic mixture was 51.7 weight percent HFC-134 and 48.3 weight percent HFC-245cb. The evaluation process and results are described in this paper.

Jetter, J.J.; Smith, N.D.; Ratanaphruks, K.; Ng, A.S.; Tufts, M.W.

1997-09-01

233

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

234

Weight and volume estimates for aluminum-air batteries designed for electric vehicle applications  

NASA Astrophysics Data System (ADS)

The weights and volumes of reactants, electrolyte, and hardware components are estimated for an aluminum-air battery designed for a 40-kW (peak), 70-kWh aluminum-air battery. Generalized equations are derived which express battery power and energy content as functions of total anode area, aluminum-anode weight, and discharge current density. Equations are also presented which express total battery weight and volume as linear combinations of the variables, anode area and anode weight. The sizing and placement of battery components within the engine compartment of typical five-passenger vehicles is briefly discussed.

Cooper, J. F.

1980-01-01

235

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

236

Experimental Study on the Wing Lift Characteristics of Biplane Micro Air Vehicle  

Microsoft Academic Search

This paper investigates wing aerodynamic characteristics used for bi-plane micro-air vehicles. Surface pressure distributions of two-dimensional biplane airfoils (4% cambered-plate airfoil) were measured at a chord Reynolds number of 6.4 × 104. Lift characteristics of three-dimensional biplane rectangular wings (aspect ratio of 3) were also measured at the same Reynolds number. It was indicated that the behaviors of laminar separation

Kohei Akiyama; Asei Tezuka; Yasuto Sunada; Kenichi Rinoie

2009-01-01

237

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

238

Ant-based swarming with positionless micro air vehicles for communication relay  

Microsoft Academic Search

Swarming without positioning information is interesting in application-oriented systems because it alleviates the need for\\u000a sensors which are dependent on the environment, expensive in terms of energy, cost, size and weight, or unusable at useful\\u000a ranges for real-life scenarios. This principle is applied to the development of a swarm of micro air vehicles (SMAVs) for\\u000a the deployment of ad hoc

Sabine Hauert; Laurent Winkler; Jean-christophe Zufferey; Dario Floreano

2008-01-01

239

Optimal path planning for unmanned air vehicles with kinematic and tactical constraints  

Microsoft Academic Search

We consider a class of 2D optimal path-planning problems for unmanned air vehicles (UAVs) with kinematic and tactical constraints. The existence of an optimal path class satisfying the UAV kinematic constraints and vector calculus are exploited to reduce this class of optimal path-planning problems to a parameter optimization problem. Illustrative tactical constraints arising in target touring and obstacle avoidance problems

Guang Yang; Vikram Kapila

2002-01-01

240

Vision-based local multi-resolution mapping and path planning for Miniature Air Vehicles  

Microsoft Academic Search

Miniature air vehicles (MAVs) are often used for low altitude flights where unknown obstacles might be encountered. Path planning and obstacle avoidance for MAVs involve planning a feasible path from an initial state to a goal state while avoiding obstacles in the environment. This paper presents a vision-based local multi-resolution mapping and path planning technique for MAVs using a forward-looking

Huili Yu; Randal W. Beard; Jeffrey Byrne

2009-01-01

241

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

Microsoft Academic Search

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

Jason L. Pereira

2008-01-01

242

Cooperative forest fire surveillance using a team of small unmanned air vehicles  

Microsoft Academic Search

The objective of this paper is to explore the feasibility of using multiple low-altitude, short endurance (LASE) unmanned air vehicles (UAVs) to cooperatively monitor and track the propagation of large forest fires. A real-time algorithm is described for tracking the perimeter of fires with an on-board infrared sensor. Using this algorithm, we develop a decentralized multiple-UAV approach to monitoring the

David W. Casbeer; Derek B. Kingston; Randal W. Beard; Timothy W. Mclain

2006-01-01

243

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

244

Robust higher-order sliding mode control for an air-breathing hypersonic vehicle model  

Microsoft Academic Search

This paper considers robust altitude and velocity tracking of the air-breathing hypersonic flight vehicles (AHFVs). Since the non-standard dynamic characteristics of AHFVs with the aerodynamic effects make the control design challenging, we linearize the nonlinear longitude dynamics of AHFVs by the trim condition. In view of atmospheric disturbance, the control problem is described as the output tracking of multi-input-and-multi-output perturbed

Liang Yang; Jianying Yang

2010-01-01

245

Air Bearing for Small Planar Vibrations  

NASA Technical Reports Server (NTRS)

Air-cushion device provides vibrations along axes 90 degrees apart. Bearing includes movable slide sandwiched between two fixed support plates. Separation between plates adjusted to standard air-bearing tolerances. Pressurized air supplied to slide so it floats between plates on cushion of air. Air exhausts on top and bottom surfaces of three arms of slide. Developed for stirring crystal-growth liquids in containers.

Wolf, M. F.

1985-01-01

246

Towards the conceptual design and construction of an unmanned small-scale air-land-water vehicle  

Microsoft Academic Search

This paper describes towards the conceptual design and construction of an unmanned small-scale air-land-water vehicle. Conceptual design refers to the initial design of parts followed by the assemblies to form components of the vehicle. The vehicle features a unique device system consists of four main components; a coaxial rotor set, propeller, suspension, and pontoon set. It independence for another when

Khalid Hasnan; Abas Ab. Wahab

2010-01-01

247

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

248

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

249

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

250

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

251

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

252

Design of a Flush Airdata System (FADS) for the Hypersonic Air Launched Option (HALO) Vehicle  

NASA Technical Reports Server (NTRS)

This paper presents a design study for a pressure based Flush airdata system (FADS) on the Hypersonic Air Launched Option (HALO) Vehicle. The analysis will demonstrate the feasibility of using a pressure based airdata system for the HALO and provide measurement uncertainty estimates along a candidate trajectory. The HALO is a conceived as a man-rated vehicle to be air launched from an SR-71 platform and is proposed as a testbed for an airbreathing hydrogen scramjet. A feasibility study has been performed and indicates that the proposed trajectory is possible with minimal modifications to the existing SR71 vehicle. The mission consists of launching the HALO off the top of an SR-71 at Mach 3 and 80,000 ft. A rocket motor is then used to accelerate the vehicle to the test condition. After the scramjet test is completed the vehicle will glide to a lakebed runway landing. This option provides reusability of the vehicle and scramjet engine. The HALO design will also allow for various scramjet engine and flowpath designs to be flight tested. For the HALO flights, measurements of freestream airdata are considered to be a mission critical to perform gain scheduling and trajectory optimization. One approach taken to obtaining airdata involves measurement of certain parameters such as external atmospheric winds, temperature, etc to estimate the airdata quantities. This study takes an alternate approach. Here the feasibility of obtaining airdata using a pressure-based flush airdata system (FADS) methods is assessed. The analysis, although it is performed using the HALO configuration and trajectory, is generally applicable to other hypersonic vehicles. The method to be presented offers the distinct advantage of inferring total pressure, Mach number, and flow incidence angles, without stagnating the freestream flow. This approach allows for airdata measurements to be made using blunt surfaces and significantly diminishes the heating load at the sensor. In the FADS concept a matrix of flush ports is placed in the vicinity of the aircraft nose, and the airdata are inferred indirectly from the measured pressures.

Whitmore, Stephen A.; Moes, Timothy R.; Deets, Dwain A. (Technical Monitor)

1994-01-01

253

Interactions between Flight Dynamics and Propulsion Systems of Air-Breathing Hypersonic Vehicles  

NASA Astrophysics Data System (ADS)

The development and application of a first-principles-derived reduced-order model called MASIV (Michigan/AFRL Scramjet In Vehicle) for an air-breathing hypersonic vehicle is discussed. Several significant and previously unreported aspects of hypersonic flight are investigated. A fortunate coupling between increasing Mach number and decreasing angle of attack is shown to extend the range of operating conditions for a class of supersonic inlets. Detailed maps of isolator unstart and ram-to-scram transition are shown on the flight corridor map for the first time. In scram mode the airflow remains supersonic throughout the engine, while in ram mode there is a region of subsonic flow. Accurately predicting the transition between these two modes requires models for complex shock interactions, finite-rate chemistry, fuel-air mixing, pre-combustion shock trains, and thermal choking, which are incorporated into a unified framework here. Isolator unstart occurs when the pre-combustion shock train is longer than the isolator, which blocks airflow from entering the engine. Finally, cooptimization of the vehicle design and trajectory is discussed. An optimal control technique is introduced that greatly reduces the number of computations required to optimize the simulated trajectory.

Dalle, Derek J.

254

Mid-Air Retrieval technology for returning of reusable launch vehicles' boosters  

NASA Astrophysics Data System (ADS)

The multilateral analysis of reusable launch vehicles (RLV) has been carried out by the authors' team within 8 years. The studies are based on the world experience and also on the large practical experience of Khrunichev Space Center in designing, production, and operation of aerospacecraft (incuding reentry one). The analysis results are monosemantic and are the following: The only one feasible principle for the nearest future is a mid-air retrieval (MAR), which will permit potentially the creation of the effective RLV. For practical realization of the results obtained, the authors in cooperation with M. L. Mil's Moscow Helicopter Plant (MHP) and "Parachute Design" Scientific Institute have developed the launch vehicles' booster MAR technology (including the structure and principles of main elements formation). The general conclusions of the mar technology are the following: (i) it can be realized with a minimal technical risk at the earliest time (2-3 years); (ii) it can be applied to the existing expendable launch vehicles (ELV) and can be easily adapted to different launch vehicles; (iii) it can be demonstrated at minimal costs and time; and (i?) it permits the creation of the most economically effective RLV (budget savings will be up to 30% and in case of using a special operation technology, the savings can attain 41.5%).

Antonenko, S. V.; Belavskiy, S. A.

2009-09-01

255

A Method to Control the Cushion Pressure of Oscillating SES  

NASA Astrophysics Data System (ADS)

A method is proposed to control the variation of cushion pressure of SES oscillating vertically. The peripheral nozzle is attached along the periphery and swings changing the discharge angle. The angle varies in accordance with the motion of the craft. A method is proposed to analyze the mechanism of this setup. The result is compared with experiments to show the agreement of the two results. It has been shown both theoretically and experimentally that the variation of the cushion pressure is effectively controlled adjusting the amplitude and the phase of the swinging motion of the nozzle.

Senba, Hiromitsu; Matsuo, Hideo; Takahashi, Hidehiko; Yoshimoto, Shintarou; Matsuo, Kensuke; Kanazawa, Koji; Hiroe, Tetsuyuki; Fujiwara, Kazuhito

256

3rd US-European Competition and Workshop on Micro Air Vehicle Systems (MAV07) & European Micro Air Vehicle Conference and Flight Competition (EMAV2007), 17-21 September 2007, Toulouse, France  

E-print Network

autonomous navigation system for multiple fixed-wing aircraft system. One of the main concern of the project3rd US-European Competition and Workshop on Micro Air Vehicle Systems (MAV07) & European Micro Air the Paparazzi UAV system, which aims to provide a free and fully autonomous autopilot for a fleet of MAV

Paris-Sud XI, Université de

257

American Institute of Aeronautics and Astronautics, InfoTech@Aerospace Conference, Paper No. 2005-7081 Intelligent Unmanned Air Vehicle Flight Systems  

E-print Network

-7081 1 Intelligent Unmanned Air Vehicle Flight Systems Jodi A. Miller* , Paul D. Minear* , and Albert F capability that is being used as a test bed for future technology development. The unmanned air vehicles is described in detail. An IC architecture directly applicable to the design of unmanned vehicles is also

258

Physical Properties of Two Biological Cushioning Materials from Wheat and Corn Starches  

Microsoft Academic Search

Cereal Chem. 72(1):38-41 Physical properties of two biological cushioning materials made from dates were significantly higher than those of the wheat starch extrudates. wheat and corn starch extrudates were compared with those of commercial Both biological cushioning materials showed similar water absorption plastic foam cushioning material. Characteristics measured included isotherms at three temperatures when the equilibrium moisture contents dimensions, bulk

W. WANG; R. A. FLORES; C. T. HUANG

259

7 CFR 1785.70 - Application of RETRF cushion of credit payments.  

...the borrower's cushion of credit account and applied as...account with RUS, its cushion of credit account will be applied...Ruddy, Director, Fiscal Accounting Division, Rural Utilities...the balance of its cushion of credit account only if the...

2014-01-01

260

7 CFR 1785.70 - Application of RETRF cushion of credit payments.  

Code of Federal Regulations, 2011 CFR

...the borrower's cushion of credit account and applied as...account with RUS, its cushion of credit account will be applied...Ruddy, Director, Fiscal Accounting Division, Rural Utilities...the balance of its cushion of credit account only if the...

2011-01-01

261

7 CFR 1785.70 - Application of RETRF cushion of credit payments.  

Code of Federal Regulations, 2010 CFR

...the borrower's cushion of credit account and applied as...account with RUS, its cushion of credit account will be applied...Ruddy, Director, Fiscal Accounting Division, Rural Utilities...the balance of its cushion of credit account only if the...

2010-01-01

262

7 CFR 1785.70 - Application of RETRF cushion of credit payments.  

Code of Federal Regulations, 2013 CFR

...the borrower's cushion of credit account and applied as...account with RUS, its cushion of credit account will be applied...Ruddy, Director, Fiscal Accounting Division, Rural Utilities...the balance of its cushion of credit account only if the...

2013-01-01

263

7 CFR 1785.70 - Application of RETRF cushion of credit payments.  

Code of Federal Regulations, 2012 CFR

...the borrower's cushion of credit account and applied as...account with RUS, its cushion of credit account will be applied...Ruddy, Director, Fiscal Accounting Division, Rural Utilities...the balance of its cushion of credit account only if the...

2012-01-01

264

Structural Sizing of a 25,000-lb Payload, Air-breathing Launch Vehicle for Single-stage-to-orbit  

NASA Technical Reports Server (NTRS)

In support of NASA's Air-Breathing Launch Vehicle (ABLV) study, a 25,000-lb payload version of the GTX (formerly Trailblazer) reference vehicle concept was developed. The GTX is a vertical lift-off, reusable, single-stage-to-orbit launch vehicle concept that uses hypersonic air-breathing propulsion in a rocket-based combined-cycle (RBCC) propulsion system to reduce the required propellant fraction. To achieve this goal the vehicle and propulsion system must be well integrated both aerodynamically and structurally to reduce weight. This study demonstrates the volumetric and structural efficiency of a vertical takeoff, horizontal landing, hypersonic vehicle with a circular cross section. A departure from the lifting body concepts, this design philosophy is even extended to the engines, which have semicircular nacelles symmetrically mounted on the vehicle. Material candidates with a potential for lightweight and simplicity have been selected from a set of near term technologies (five to ten years). To achieve the mission trajectory, preliminary weight estimates show the vehicle's gross lift-off weight is 1.26 x 10(exp 6) lb. The structural configuration of the GTX vehicle and its propulsion system are described. The vehicle design benefits are presented, and key technical issues are highlighted.

Roche, Joseph M.; Kosareo, Daniel N.

2001-01-01

265

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...

266

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

267

A proposed computational technique for obtaining hypersonic air data on a sharp-nosed vehicle  

NASA Technical Reports Server (NTRS)

A computational technique has been developed to obtain final air data quantities for a sharp-nosed hypersonic vehicle. Pressure measurements from five flush pressure ports are the only input needed. Four of the ports are installed around the forebody circumference and the fifth is on the nose. The pressure model is based on Lees-modified Newtonian method and corrected by pressure data from computational fluid dynamics analysis. Although this approach is similar to that used for the blunt-nosed space shuttle, it is designed specifically for a sharp-nosed aircraft. The potential of this method has been demonstrated, especially in obtaining values for dynamic pressure and angle of attack.

Tarasidis, Jamie B.; Hellbaum, R. F.; Garner, H. Douglas

1990-01-01

268

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

269

Air Cushion Press for Excellent Uniformity, High Yield, and Fast  

E-print Network

and is often used in home-built NIL tools as well as many commercial NIL machines. However, SPP suffers several nanopatterning techniques, NIL offers a unique combination of ultrahigh resolution, low cost, and high throughput

270

Sucrose Cushion Tucson Marine Phage Lab Page 1 of 4  

E-print Network

Sucrose Cushion B. Poulos Tucson Marine Phage Lab Page 1 of 4 Purifying Viruses Using Sucrose., & Sullivan, M. B. (2012). Evaluation of methods to concentrate and purify ocean virus communities through tubes with SM buffer or sterile water. The SW 40 tubes hold 12 ml total

Sullivan, Matthew B.

271

Cushioning and lateral stability functions of cloth sport shoes.  

PubMed

In this study, we evaluated the protective functions of cloth sport shoes, including cushioning and lateral stability. Twelve male students participated in the study (mean +/- s: age 12.7 +/- 0.4 years, mass 40.7 +/- 5.9kg, height 1.50 +/- 0.04m). Cloth sport shoes, running shoes, basketball shoes, crosstraining shoes, and barefoot conditions were investigated in random sequence. Human pendulum and cutting movement tests were used to assess cushioning performance and lateral stability, respectively. For cushioning, the running shoes (2.06 body weight, BW) performed the best, while the cross-training shoes (2.30 BW) and the basketball shoes (2.37 BW) both performed better than the cloth sport shoes (2.55 BW) and going barefoot (2.63 BW). For the lateral stability test, range of inversion--eversion was found to be from 3.6 to 4.9 degrees, which was far less than that for adult participants (> 20 degrees). No significant differences were found between conditions. All conditions showed prolonged durations from foot-strike to maximum inversion (66-95 ms), which was less vigorous than that for adult participants (< 40 ms) and was unlikely to evoke intrinsic stability failure. In conclusion, the cloth sport shoe showed inferior cushioning capability but the same lateral stability as the other sports shoes for children. PMID:17933201

Fong, Daniel Tik-Pui; Hong, Youlian; Li, Jing Xian

2007-09-01

272

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

273

21 CFR 890.3175 - Flotation cushion.  

Code of Federal Regulations, 2011 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...

2011-04-01

274

21 CFR 890.3175 - Flotation cushion.  

Code of Federal Regulations, 2013 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...

2013-04-01

275

21 CFR 890.3175 - Flotation cushion.  

Code of Federal Regulations, 2010 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...

2010-04-01

276

21 CFR 890.3175 - Flotation cushion.  

...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...

2014-04-01

277

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

278

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

279

Design and development considerations for biologically inspired flapping-wing micro air vehicles  

NASA Astrophysics Data System (ADS)

In this paper, the decade of numerical and experimental investigations leading to the development of the authors' unique flapping-wing micro air vehicle is summarized. Early investigations included the study of boundary layer energization by means of a small flapping foil embedded in a flat-plate boundary layer, the reduction of the recirculatory flow region behind a backward-facing step by means of a small flapping foil, and the reduction or suppression of flow separation behind blunt or cusped airfoil trailing edges by flapping a small foil located in the wake flow region. These studies were followed by systematic investigations of the aerodynamic characteristics of single flapping airfoils and airfoil combinations. These unsteady flows were described using flow visualization, laser-Doppler velocimetry in addition to panel and Navier-Stokes computations. It is then shown how this flapping-wing database was used to conceive, design and develop a micro air vehicle which has a fixed wing for lift and two flapping wings for thrust generation. While animal flight is characterized by a coupled force generation, the present design appears to separate lift and thrust. However, in fact, the performance of one surface is closely coupled to the other surfaces.

Jones, Kevin D.; Platzer, Max F.

280

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

281

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

282

Control of air pollution from new motor vehicle and new motor vehicle engines: submission of altitude performance adjustments for motor vehicles  

SciTech Connect

This U.S. Environmental Protection Agency notice establishes final rules requiring manufacturers of 1981 and earlier model year motor vehicles and motor vehicle engines to submit altitude adjustment instructions for in-use motor vehicles and motor vehicle engines within one year of the effective date. Similar instructions must also be submitted for 1982 and later model year motor vehicles and motor vehicle engines within 30 days from the date on which a certificate of conformity is issued by EPA. These rules are intended to improve the emission control performance of 1981 and later model year light-duty vehicles and light-duty trucks and 1980 and later model year motorcycles that are not designed for operation at high altitude (over 4000 ft above sea level). The rules will become effective on 11/7/80.

Not Available

1980-10-08

283

Cushioning and lateral stability functions of cloth sport shoes  

Microsoft Academic Search

In this study, we evaluated the protective functions of cloth sport shoes, including cushioning and lateral stability. Twelve male students participated in the study (mean ± s: age 12.7 ± 0.4 years, mass 40.7 ± 5.9 kg, height 1.50 ± 0.04 m). Cloth sport shoes, running shoes, basketball shoes, cross-training shoes, and barefoot conditions were investigated in random sequence. Human pendulum and cutting movement tests were used to assess

Daniel Tik-Pui Fong; Youlian Hong; Jing Xian Li

2007-01-01

284

Continuous high order sliding mode controller design for a flexible air-breathing hypersonic vehicle.  

PubMed

This paper investigates the problem of tracking control with uncertainties for a flexible air-breathing hypersonic vehicle (FAHV). In order to overcome the analytical intractability of this model, an Input-Output linearization model is constructed for the purpose of feedback control design. Then, the continuous finite time convergence high order sliding mode controller is designed for the Input-Output linearization model without uncertainties. In addition, a nonlinear disturbance observer is applied to estimate the uncertainties in order to compensate the controller and disturbance suppression, where disturbance observer and controller synthesis design is obtained. Finally, the synthesis of controller and disturbance observer is used to achieve the tracking for the velocity and altitude of the FAHV and simulations are presented to illustrate the effectiveness of the control strategies. PMID:24534328

Wang, Jie; Zong, Qun; Su, Rui; Tian, Bailing

2014-05-01

285

Monitoring of atmospheric aerosol emissions using a remotely piloted air vehicle (RPV)-Borne Sensor Suite  

SciTech Connect

We have developed a small sensor system, the micro-atmospheric measurement system ({mu}-AMS), to monitor and track aerosol emissions. The system was developed to fly aboard a remotely piloted air vehicle, or other mobile platform, to provide real-time particle measurements in effluent plumes and to collect particles for chemical analysis. The {mu}-AMS instrument measures atmospheric parameters including particle mass concentration and size distribution, temperature, humidity, and airspeed, altitude and position (by GPS receiver) each second. The sensor data are stored onboard and are also down linked to a ground station in real time. The {mu}-AMS is battery powered, small (8 in. dia x 36 in.), and lightweight (15 pounds). Aerosol concentrations and size distributions from above ground explosive tests, airbone urban pollution, and traffic-produced particulates are presented.

NONE

1996-05-01

286

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

287

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

288

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

289

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

290

Design of elevator control surface actuated by LIPCA for small unmanned air vehicle  

NASA Astrophysics Data System (ADS)

There have been persistent interests in high performance actuators suitable for the actuation of control surfaces of small aircraft and helicopter blades and for active vibration control of aerospace and submarine structures that need high specific force and displacement. What is really needed for active actuation is a large-displacement actuator with a compact source, i.e., much higher strain. A lot of effort has been made to develop compact actuators with large displacement at a high force. One of the representative actuator is LIPCA actuator that was introduced by Yoon et al. The LIPCA design offers the advantages to be applied as actuator for the small aerial vehicle comparing with any other actuators. The weight is one of the main concerns for aerospace field, and since LIPCA has lighter weight than any other piezo-actuator thus it is suitable as actuator for small aircraft control surface. In this paper, a conceptual design of LIPCA-actuated control surface is introduced. A finite element model was constructed and analyzed to predict the deflection angle of the control surface. The hinge moment that produced by the aerodynamic forces was calculated to determine the optimum position of the hinge point, which could produce the deflection as high as possible with reasonable hinge moment. To verify the prediction, a prototype of SUAV (small unmanned air vehicle) control surface was manufactured and tested both in static condition and in the wind tunnel. The prediction and test results showed a good agreement on the control surface deflection angle.

Yoon, K. J.; Setiawan, Hery; Goo, N. S.

2006-03-01

291

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

292

Preliminary development of a VTOL unmanned air vehicle for the close-range mission  

NASA Astrophysics Data System (ADS)

The preliminary development of a full-scale Vertical Takeoff and Landing (VTOL) Unmanned Air Vehicle (UAV) for the Close-Range mission was completed at the Naval Postgraduate School (NPS). The vehicle was based on half-scale ducted-fan investigations performed at the UAV Flight Research Lab. The resulting design is a fixed-duct, tail-sitter UAV with a canard-configured horizontal stabilizer. Major airframe components are used from previous UAV's and include the wings from a U.S. Army Aquila and the ducted fan from the U.S. Marine Corps AROD. Accomplishments include: (1) the design and fabrication of a carry-through spar, and (2) the design and construction of an engine test stand. The through spar was designed using finite element analysis and constructed from composite materials. The purpose of the test stand is to measure torque, horsepower, and thrust of an entire ducted fan or an individual engine. Completion of this thesis will pave the way for future NPS research into the growing interest in VTOL UAV technology.

Kress, Gregory A.

1992-09-01

293

The development of aluminum-air batteries for application in electric vehicles  

NASA Astrophysics Data System (ADS)

The recently concluded program, jointly funded by ELTECH Research Corporation and the Department of Energy, focused upon the development of an aluminum-air battery system for electric vehicle applications. The operation of the aluminum-air battery involves the dissolution of aluminum to produce a current and aluminate. Initially the objectives were to evaluate and optimize the battery design that was developed prior to this program (designated as the B300 cell) and to design and evaluate the components of the auxiliary system. During the program, three additional tasks were undertaken, addressing needs identified by ELTECH and by Sandia National Laboratories. First, the capability to produce aluminum alloys as relatively large ingots (100 to 150 lbs), with the required electrochemical performance, was considered essential to the development of the battery. The second additional task was the adoption of an advanced cell (designated as the AT400 cell), designed by ELTECH in a different program. Finally, it was recognized that a system model would allow evaluation of the interactions of the several unit operations involved in the battery. Therefore, the development of a mathematical model, based upon material and energy balances for the battery, was undertaken. At a systems level, sufficient information was obtained in the completion of this program to support the design, fabrication and operation of a batch or solids-free battery system. For the first time, the components of the auxiliary system, i.e., a heat exchanger, carbon dioxide scrubber and hydrogen disposal technology, have been defined for a vehicle battery. Progress on each component or system is summarized in the following sections.

Rudd, E. J.; Lott, S.

1990-12-01

294

The development of aluminum-air batteries for application in electric vehicles  

SciTech Connect

The recently concluded program, jointly funded by ELTECH Research Corporation and the Department of Energy, focused upon the development of an aluminum-air battery system for electric vehicle applications. The operation of the aluminum-air battery involves the dissolution of aluminum to produce a current and aluminate. Initially the objectives were to evaluate and optimize the battery design that was developed prior to this program (designated as the B300 cell) and to design and evaluate the components of the auxiliary system. During the program, three additional tasks were undertaken, addressing needs identified by ELTECH and by Sandia National Laboratories. First, the capability to produce aluminum alloys as relatively large ingots (100--150 lbs), with the required electrochemical performance, was considered essential to the development of the battery. The second additional task was the adoption of an advanced cell (designated as the AT400 cell), designed by ELTECH in a different program. Finally, it was recognized that a system model would allow evaluation of the interactions of the several unit operations involved in the battery. Therefore, the development of a mathematical model, based upon material and energy balances for the battery, was undertaken. At a systems level, sufficient information was obtained in the completion of this program to support the design, fabrication and operation of a batch'' or solids-free'' battery system. For the first time, the components of the auxiliary system, i.e., a heat exchanger, carbon dioxide scrubber and hydrogen disposal technology, have been defined for a vehicle battery. Progress on each component or system is summarized in the following sections.

Rudd, E.J. (ELTECH Systems Corp., Fairport Harbor, OH (United States). Research and Development Center); Lott, S. (Sandia National Labs., Albuquerque, NM (United States))

1990-12-01

295

Progress In Electromagnetics Research Symposium Proceedings, Cambridge, USA, July 58, 2010 635 A Telemetry Antenna System for Unmanned Air Vehicles  

E-print Network

A Telemetry Antenna System for Unmanned Air Vehicles M. Dogan1, 2 and F. Ustuner1 1 TUBITAK, UEKAE, Kocaeli telemetry antenna system manufac- tured for UAVs that provides 360 coverage in the roll plane of the UAV. Proposed telemetry antenna system includes four telemetry antennas, one power divider that has one input

Yanikoglu, Berrin

296

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

297

Multidisciplinary design and optimization of an air launched satellite launch vehicle using a hybrid heuristic search algorithm  

Microsoft Academic Search

A multidisciplinary design and optimization strategy for a multistage air launched satellite launch vehicle comprising of a solid propulsion system to low earth orbit with the implementation of a hybrid heuristic search algorithm is proposed in this article. The proposed approach integrated the search properties of a genetic algorithm and simulated annealing, thus achieving an optimal solution while satisfying the

A. F. Rafique; L. S. He; Q. Zeeshan; A. Kamran; K. Nisar

2011-01-01

298

The possibilities of chosen applications of control and navigation systems in general aviation aircraft and unmanned air vehicles  

Microsoft Academic Search

The development of informatics and sensor techniques has extended the possibilities of flight parameter measurement. It allows for extensive modification of control and navigation systems in air vehicles. This advance can also be noticed in the research of the Department of Avionics and Control at the Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology. Research in the area

J. Gruszecki; A. Tomczyk; Boguslaw Dolega; T. Rogalski; P. Rzucid?o

2007-01-01

299

The impact of China's vehicle emissions on regional air quality in 2000 and 2020: a scenario analysis  

NASA Astrophysics Data System (ADS)

The number of vehicles in China has been increasing rapidly. We evaluate the impact of current and possible future vehicle emissions from China on Asian air quality. We modify the Regional Emission Inventory in Asia (REAS) for China's road transport sector in 2000 using updated Chinese data for vehicle numbers, annual mileage and emission factors. We develop two scenarios for 2020: a scenario where emission factors remain the same as they were before any regulation was implemented (business-as-usual, BAU), and a scenario where Euro 3 vehicle emission standards are applied to all vehicles (except motorcycles and rural vehicles). The Euro 3 scenario is an approximation of what may be the case in 2020 as, starting in 2008, all new gasoline and diesel vehicles in China (except motorcycles) were required to meet the Euro 3 emission standards. Using the Weather Research and Forecasting model coupled with Chemistry (WRF/Chem), we examine the regional air quality response to China's vehicle emissions in 2000 and in 2020 for the BAU and Euro 3 scenarios. We evaluate the 2000 model results with observations in Japan, China, Korea, and Russia. Under BAU in 2020, emissions of carbon monoxide (CO), nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOCs), black carbon (BC) and organic carbon (OC) from China's vehicles more than double compared to the 2000 baseline. If all vehicles meet the Euro 3 regulations in 2020, however, these emissions are reduced by more than 50% relative to BAU. The implementation of stringent vehicle emission standards leads to a large, simultaneous reduction of the surface ozone (O3) mixing ratios and particulate matter (PM2.5) concentrations. In the Euro 3 scenario, surface O3 is reduced by more than 10 ppbv and surface PM2.5 is reduced by more than 10 ?g m-3 relative to BAU in Northeast China in all seasons. In spring, surface O3 mixing ratios and PM2.5 concentrations in neighboring countries are also reduced by more than 3 ppbv and 1 ?g m-3, respectively. We find that effective regulation of China's road transport sector will be of significant benefit for air quality both within China and across East Asia as well.

Saikawa, E.; Kurokawa, J.; Takigawa, M.; Mauzerall, D. L.; Horowitz, L. W.; Ohara, T.

2011-04-01

300

Design and fabrication of microflap actuators for steering of micro air vehicles  

NASA Astrophysics Data System (ADS)

This paper presents the design, analysis, and fabrication of an array of microflap actuators that can produce a substantial aerodynamic force for course corrections of Micro Air Vehicles (MAVs) and low speed projectiles. In the past, several actuation principles, including microjet, magnetic and bubble actuators, and flapping wings have been proposed, and had varying degrees of success. In this paper, we discuss the benefits and drawbacks of past attempts, and the technology that can be used to address the microflap steering problem. We propose a hybrid microflap actuation scheme that combines two types of actuators including: 1) a MEMS fabricated "active" microactuator connected to a microflap, and 2) a "passive" fluidic channel system that harvests the potential energy in the high pressure field on the leading edge of the MAV or high speed projectile to achieve a desired deflection. An array of microflap actuators was prototyped using silicon MEMS fabrication and microassembly. A Silicon On Insulator (SOI) wafer with 100 micron thick device layer was used to as a substrate material to fabricate microflap structures with springs. Front and back side DRIE process was used to etch and release the microstructures including microflaps. Then, the microactuator was assembled on top of the microflap. The static and dynamic behaviors of a microflap were measured using a laser displacement sensor and were compared to the analytic model. In the near future, a prototyped microflap will be tested inside of a wind tunnel to measure the lift and drag at various air speeds.

Zimbru, George C.; Lee, Woo Ho; Popa, Dan O.

2009-05-01

301

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

302

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

303

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

304

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

305

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.

306

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

Federal Register 2010, 2011, 2012, 2013

...requires auto manufacturers to include a ``smog index'' label on each vehicle sold...2025. The program combines the control of smog, soot and global warming gases and...vehicle recall provisions, to amend its smog label requirements, and to revise...

2012-08-23

307

Design of composite plastic foams for improved cushioning  

E-print Network

cushioning displays nonlinearity. The purpose of shock isolation is to absorb the energy of a sudden, sharp impact, and then release it over a longer period of response time. Shock isolation generally requires greater stiffness characteristics and strain... is the spring constant, and 6 = u ? x is the deflection of the isolation medium. At the initial conditions t = 0 and u = 0, the downward velocity of the container is zero and the velocity of the package item is x = J(2gh), where h is the drop height...

Eskew, James Oliver

2012-06-07

308

Police officer in-vehicle discomfort: appointments carriage method and vehicle seat features.  

PubMed

Musculoskeletal pain is commonly reported by police officers. A potential cause of officer discomfort is a mismatch between vehicle seats and the method used for carrying appointments. Twenty-five police officers rated their discomfort while seated in: (1) a standard police vehicle seat, and (2) a vehicle seat custom-designed for police use. Discomfort was recorded in both seats while wearing police appointments on: (1) a traditional appointments belt, and (2) a load-bearing vest/belt combination (LBV). Sitting in the standard vehicle seat and carrying appointments on a traditional appointments belt were both associated with significantly elevated discomfort. Four vehicle seat features were most implicated as contributing to discomfort: back rest bolster prominence; lumbar region support; seat cushion width; and seat cushion bolster depth. Authorising the carriage of appointments using a LBV is a lower cost solution with potential to reduce officer discomfort. Furthermore, the introduction of custom-designed vehicle seats should be considered. PMID:24681072

Filtness, A J; Mitsopoulos-Rubens, E; Rudin-Brown, C M

2014-07-01

309

MODELING, TESTING AND CORRELATION OF INTERLINKED AIR SUSPENSION SYSTEMS FOR PREMIUM VEHICLE PLATFORMS  

Microsoft Academic Search

Since a vehicle is actuated by road irregularities in many different ways the improvement of the passengers driving comfort is a major focus of automotive research and development work especially in the premium vehicle segment. Apart from the acoustic properties of a vehicle generally referred to as NVH (noise vibration harshness), the low- frequent and mechanical kind of vibrations mainly

Michael Frantzen

310

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

E-print Network

with Unmanned Ground Vehicles (UGVs). Both systems have different mobility and perception abilities. UAV systems and commercial operations. The improved perception abilities of UAVs compared with unmanned ground vehicles (UGVs unmanned ground vehicle systems. This research incorporates the abilities of UAV/UGV systems to support

Florida, University of

311

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

312

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

313

The novel aerodynamics of insect flight: applications to micro-air vehicles.  

PubMed

The wing motion in free flight has been described for insects ranging from 1 to 100 mm in wingspan. To support the body weight, the wings typically produce 2-3 times more lift than can be accounted for by conventional aerodynamics. Some insects use the fling mechanism: the wings are clapped together and then flung open before the start of the downstroke, creating a lift-enhancing vortex around each wing. Most insects, however, rely on a leading-edge vortex (LEV) created by dynamic stall during flapping; a strong spanwise flow is also generated by the pressure gradients on the flapping wing, causing the LEV to spiral out to the wingtip. Technical applications of the fling are limited by the mechanical damage that accompanies repeated clapping of the wings, but the spiral LEV can be used to augment the lift production of propellers, rotors and micro-air vehicles (MAVs). Design characteristics of insect-based flying machines are presented, along with estimates of the mass supported, the mechanical power requirement and maximum flight speeds over a wide range of sizes and frequencies. To support a given mass, larger machines need less power, but smaller ones operating at higher frequencies will reach faster speeds. PMID:10562527

Ellington, C P

1999-12-01

314

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

315

On the mechanics, computational modeling, and design implementation of piezoelectric actuators on micro air vehicles  

NASA Astrophysics Data System (ADS)

This document details the research performed on applying piezoelectric macro fiber composite actuators on micro air vehicles. The research objective was to apply the minimum number of macro fiber composites to the aircraft in an optimized manner in order to obtain complete control authority. To do this, a local-global approach was taken. Numerical predictions, experiments, and finite element models were used to model the macro fiber composites in a local manner, approximating the curvature of the actuator when bonded to a substrate. The substrate was selected to maximize the curvature when submitted to expected loads. In a global manner, the design of the aircraft was optimized, using a computational model, to provide the largest control authority under expected flight conditions. A variety of experimental tests were conducted to create an accurate aeroelastic computer model, including tests to determine material properties, static loading tests, and wind tunnel testing. Two of the optimized designs were tested in the wind tunnel to verify the predicted improvement, which confirmed the accuracy of the computer model. Other experimental results are also included, including experiments examining the unimorph fabrication technique, rigid assumptions used for the aerodynamic model, and high frequency dynamics of the macro fiber composite unimorph.

Lacroix, Bradley W.

316

Fixed membrane wings for micro air vehicles: Experimental characterization, numerical modeling, and tailoring  

NASA Astrophysics Data System (ADS)

Fixed wing micro air vehicles (wingspan between 10 and 15 cm) are aerodynamically challenging due to the low Reynolds number regime (10 4-10 5) they operate in. The low aspect ratio wings (typically used to maximize area under a size constraint) promote strong tip vortices, and are susceptible to rolling instabilities. Wind gusts can be of the same order of magnitude as the flight speed (10-15 m/s). Standard control surfaces on an empennage must be eliminated for size considerations and drag reduction, and the range of stable center of gravity locations is only a few millimeters long. Membrane aeroelasticity has been identified as a tenable method to alleviate these issues: flexible wing structures with geometric twist (adaptive washout for gust rejection, delayed stall) and aerodynamic twist (adaptive inflation for high lift, larger stability margins) are both considered here. Recent investigations in static aeroelastic characterization, including flight loads, wing deformation, flow structures, aeroelastic-tailoring studies through laminate orientation, as well as unconventional techniques based on membrane pre-tension, are reviewed. Multi-objective optimization aimed at improving lift, drag, and pitching moment considerations is also discussed.

Stanford, Bret; Ifju, Peter; Albertani, Roberto; Shyy, Wei

2008-05-01

317

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

318

Dynamic stability test results on an 0.024 scale B-1 air vehicle  

NASA Technical Reports Server (NTRS)

Dynamic longitudinal and lateral-directional stability characteristics of the B-1 air vehicle were investigated in three wind tunnels at the Langley Research Center. The main rotary derivatives were obtained for an angle of attack range of -3 degrees to +16 degrees for a Mach number range of 0.2 to 2.16. Damping in roll data could not be obtained at the supersonic Mach numbers. The Langley 7 x 10 foot high speed tunnel, the 8 foot transonic pressure tunnel, and the 4 foot Unitary Plan wind tunnel were the test sites. An 0.024 scale light-weight model was used on a forced oscillation type balance. Test Reynolds number varied from 474,000/ft to 1,550,000/ft. through the Mach number range tested. The results showed that the dynamic stability characteristics of the model in pitch and roll were generally satisfactory up to an angle attack of about +6 degrees. In the wing sweep range from 15 to 25 degrees the positive damping levels in roll deteriorated rapidly above +2 degrees angle of attack. This reduction in roll damping is believed to be due to the onset of separation over the wing as stall is approached.

Beeman, R. R.

1972-01-01

319

Inflorescences of alpine cushion plants freeze autonomously and may survive subzero temperatures by supercooling  

Microsoft Academic Search

Freezing patterns in the high alpine cushion plants Saxifraga bryoides, Saxifraga caesia, Saxifraga moschata and Silene acaulis were studied by infrared thermography at three reproductive stages (bud, anthesis, fruit development). The single reproductive shoots of a cushion froze independently in all four species at every reproductive stage. Ice formation caused lethal damage to the respective inflorescence. After ice nucleation, which

Jürgen Hacker; Ursula Ladinig; Johanna Wagner; Gilbert Neuner

2011-01-01

320

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

321

Air-breathing hypersonic vehicle guidance and control studies; An integrated trajectory/control analysis methodology: Phase 1  

NASA Technical Reports Server (NTRS)

A tool which generates optimal trajectory/control histories in an integrated manner is generically adapted to the treatment of single-stage-to-orbit air-breathing hypersonic vehicles. The methodology is implemented as a two point boundary value problem solution technique. Its use permits an assessment of an entire near-minimum-fuel trajectory and desired control strategy from takeoff to orbit while satisfying physically derived inequality constraints and while achieving efficient propulsive mode phasing. A simpler analysis strategy that partitions the trajectory into several boundary condition matched segments is also included to construct preliminary trajectory and control history representations with less computational burden than is required for the overall flight profile assessment. A demonstration was accomplished using a tabulated example (winged-cone accelerator) vehicle model that is combined with a newly developed multidimensional cubic spline data smoothing routine. A constrained near-fuel-optimal trajectory, imposing a dynamic pressure limit of 1000 psf, was developed from horizontal takeoff to 20,000 ft/sec relative air speed while aiming for a polar orbit. Previously unspecified propulsive discontinuities were located. Flight regimes demanding rapid attitude changes were identified, dictating control effector and closed-loop controller authority was ascertained after evaluating effector use for vehicle trim. Also, inadequacies in vehicle model representations and specific subsystem models with insufficient fidelity were determined based on unusual control characteristics and/or excessive sensitivity to uncertainty.

Hattis, Philip D.; Malchow, Harvey L.

1991-01-01

322

A complete passive or imaging-based sensor system for unmanned air vehicle taking off and landing operations  

Microsoft Academic Search

We have successfully developed an innovative, miniaturized, and lightweight PTZ UCAV imager called OmniBird for unmanned air vehicle taking off and landing operations. OmniBird is developed through a SBIR funding from NAVAIR. It is to fit in 8 in3. The designed zoom capability allows it to acquire focused images for targets ranging from 10 to 250 feet. The innovative panning

Steven Yi

2008-01-01

323

Study on operating characteristics of fuel cell powered electric vehicle with different air feeding systems  

Microsoft Academic Search

In this paper the modeling of a fuel cell powered electric vehicle is presented. The fuel cell system consisting of a proton\\u000a exchange membrane (PEM) fuel cell stack and balance of plant (BOP) was co-simulated with a commercial vehicle simulation program.\\u000a The simulation program calculates the load of the fuel cell depending on the driving mode of the vehicle and

Junghwan Bang; Han-Sang Kim; Dong-Hun Lee; Kyoungdoug Min

2008-01-01

324

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

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

To cite this document: Prothin, Sebastien and Moschetta, Jean-Marc A Vectoring Thrust Coaxial Rotor for Micro Air Vehicle: Modeling, Design and Analysis. (2013) In  

E-print Network

To cite this document: Prothin, Sebastien and Moschetta, Jean-Marc A Vectoring Thrust Coaxial Rotor Coaxial Rotor for Micro Air Vehicle: Modeling, Design and Analysis Sebastien PROTHIN(1) , Jean configuration of coaxial rotor as applied to a micro aerial vehicle (MAV) with the intention to guarantee

Mailhes, Corinne

327

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

328

Simulation of the evolution of particle size distributions in a vehicle exhaust plume with unconfined dilution by ambient air.  

PubMed

Over the past several years, numerous studies have linked ambient concentrations of particulate matter (PM) to adverse health effects, and more recent studies have identified PM size and surface area as important factors in determining the health effects of PM. This study contributes to a better understanding of the evolution of particle size distributions in exhaust plumes with unconfined dilution by ambient air. It combines computational fluid dynamics (CFD) with an aerosol dynamics model to examine the effects of different streamlines in an exhaust plume, ambient particle size distributions, and vehicle and wind speed on the particle size distribution in an exhaust plume. CFD was used to calculate the flow field and gas mixing for unconfined dilution of a vehicle exhaust plume, and the calculated dilution ratios were then used as input to the aerosol dynamics simulation. The results of the study show that vehicle speed affected the particle size distribution of an exhaust plume because increasing vehicle speed caused more rapid dilution and inhibited coagulation. Ambient particle size distributions had an effect on the smaller sized particles (approximately 10 nm range under some conditions) and larger sized particles (>2 microm) of the particle size distribution. The ambient air particle size distribution affects the larger sizes of the exhaust plume because vehicle exhaust typically contains few particles larger than 2 microm. Finally, the location of a streamline in the exhaust plume had little effect on the particle size distribution; the particle size distribution along any streamline at a distance x differed by less than 5% from the particle size distributions along any other streamline at distance x. PMID:15887887

Jiang, Pengzhi; Lignell, David O; Kelly, Kerry E; Lighty, JoAnn S; Sarofim, Adel F; Montgomery, Christopher J

2005-04-01

329

Air quality impacts of using overnight electricity generation to charge plug-in hybrid electric vehicles for daytime use  

NASA Astrophysics Data System (ADS)

The air quality impacts of replacing 20% of the gasoline powered light duty vehicle miles traveled with plug-in hybrid electric vehicles (PHEVs) in the region served by the Pennsylvania, New Jersey, Maryland classic grid are examined. Unutilized, base-load nighttime electricity generating capacity is assumed to charge PHEVs that would subsequently be used during urban commutes. The net impact of this scenario on the emissions of precursors to the formation of ozone is an increase in nitrogen oxide (NOx), volatile organic compound (VOC) and CO emissions from electricity generating units during nighttime hours, and a greater decrease in NOx, VOC and CO from mobile emissions in urban areas during daytime hours. The changes in maximum daily 8 h ozone concentrations, predicted using a regional photochemical model (CAMx), are decreases in ozone concentrations between 2 and 6 ppb that are widespread across the urban areas, and increases in ozone concentrations of up to 8 ppb in highly localized areas. Air quality indicators beyond maximum daily ozone concentration are also evaluated, and in general indicate air quality improvements associated with the use of PHEVs. However, a limited number of air quality indicators worsened with the use of PHEVs, suggesting that overall impacts of the use of PHEVs will be complex.

Thompson, Tammy; Webber, Michael; Allen, David T.

2009-01-01

330

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.

331

Flight path following guidance for unmanned air vehicles with pan-tilt camera for target observation  

Microsoft Academic Search

An Unmanned Autonomous Vehicle (UAV) is equipped with a nose-mounted camera capable of pan and tilt rotation for the observation of ground targets. The two camera angles are adjusted automatically in order to keep the target in the camera's field of view. While the camera actuators are fast enough to keep up with vehicle motion, the limited range of the

S. Stolle; Rolf Rysdyk

2003-01-01

332

Drive-by Motor Vehicle Emissions: Immediate Feedback in Reducing Air  

E-print Network

to display individual vehicle emissions information to passing drivers. Called the Smart Sign, the system merged highway messaging and on-road vehicle emissions sensing into a cost- effective public information system. The Smart Sign used a combination of words, colors, and graphics to connect with its audience

Denver, University of

333

A visual navigation system for autonomous flight of micro air vehicles  

Microsoft Academic Search

Many applications of unmanned aerial vehicles (UAVs) require the capability to navigate to some goal and to perform precise and safe landing. In this paper, we present a visual navigation system as an alternative pose estimation method for environments and situations in which GPS is unavailable. The developed visual odometer is an incremental procedure that estimates the vehicle's ego-motion by

Farid Kendoul; Kenzo Nonami

2009-01-01

334

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

...Pollution From New and In-Use Light-Duty Vehicles, Light-Duty Trucks, and Complete Otto-Cycle Heavy-Duty Vehicles § 86.1832-01... (3) The weight of the options must be included in the design curb weight and must also be represented in the weight of...

2014-07-01

335

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

Federal Register 2010, 2011, 2012, 2013

...air conditioning end- use within the refrigeration and air conditioning sector. EPA finds...HFO-1234yf in the air conditioning or refrigeration systems of heavy-duty trucks...refrigerant for MVAC, as well as for other refrigeration and air conditioning uses that...

2011-03-29

336

Stress analysis of cushion form bearings for total hip replacements.  

PubMed

Cushion form bearings comprise a thin layer of low elastic modulus material on the articulating surface of the bearing, which can deform to help preserve a film of lubricant between the bearing surfaces and therefore reduce friction and wear. The long-term function of this type of bearing is dependent on the strength and durability of this compliant layer. Finite difference and finite element methods have been used to analyse the stress distribution in the compliant layer of cushion form bearing for artificial hip joints under physiological loading conditions. A good agreement between finite difference and finite element methods was found. Under normal loading, the highest value of the maximum shear stress was found to be at the interface between the compliant layer and the more rigid substrate close to the edge of the contact. The values of maximum shear stress in the centre of the contact close to the articulating surface were lower than in the equivalent Hertzian contact. A friction force acting at the surface had little effect on the stress distribution for coefficients of friction less than 0.05. However, for higher values of friction coefficient (larger than 0.2), corresponding to inadequate lubrication, the maximum shear stress increased by a factor of four and was found to be located at the surface. The analysis predicts that the mode of failure will be at the interface with the substrate under fluid film or mixed lubrication conditions and at the articulating surface when the bearing runs dry with higher levels of friction. Both failure modes have been observed experimentally under the conditions specified. PMID:1670079

Jin, Z M; Dowson, D; Fisher, J

1991-01-01

337

Structural Sizing of a Horizontal Take-Off Launch Vehicle with an Air Collection and Enrichment System  

NASA Technical Reports Server (NTRS)

In support of NASA's Next Generation Launch Technology (NGLT) program, the Andrews Gryphon booster was studied. The Andrews Gryphon concept is a horizontal lift-off, two-stage-to-orbit, reusable launch vehicle that uses an air collection and enrichment system (ACES). The purpose of the ACES is to collect atmospheric oxygen during a subsonic flight loiter phase and cool it to cryogenic temperature, ultimately resulting in a reduced initial take-off weight To study the performance and size of an air-collection based booster, an initial airplane like shape was established as a baseline and modeled in a vehicle sizing code. The code, SIZER, contains a general series of volume, surface area, and fuel fraction relationships that tie engine and ACES performance with propellant requirements and volumetric constraints in order to establish vehicle closure for the given mission. A key element of system level weight optimization is the use of the SIZER program that provides rapid convergence and a great deal of flexibility for different tank architectures and material suites in order to study their impact on gross lift-off weight. This paper discusses important elements of the sizing code architecture followed by highlights of the baseline booster study.

McCurdy, David R.; Roche, Joseph M.

2004-01-01

338

National Fuel Cell Vehicle Learning Demonstration: Gen 2 Progress. California Air Resources Board 2009 ZEV Symposium. Session 2: Automotive Fuel Cell Vehicle Technologies.  

National Technical Information Service (NTIS)

Partial Contents: Fuel Cell Vehicle Learning Demonstration Project Objectives and Targets; Industry Partners: Four Automaker/Energy-Supplier Teams; Vehicle Deployment Complete at 140 FCVs, Some Early Vehicles Retired; DOE Learning Demo Fleet Has Surpassed...

J. Garbak, J. Kurtz, K. Wipke, S. Sprik, T. Ramsden

2009-01-01

339

An experimental investigation of a micro air vehicle-scale cycloidal rotor in forward flight  

NASA Astrophysics Data System (ADS)

The current research aims to explore the forward flight capability of an unconventional rotary-wing concept for micro air vehicle (MAV) applications, known as the cycloidal rotor (or cyclorotor). Two approaches are undertaken to fulfill this objective: 1) performance studies to examine the time-averaged forces produced by the cyclorotor, and 2) flow field studies to investigate the underlying physics of force production. In the performance studies, the dependence of time-averaged lift, propulsive force and power on blade pitching kinematics, rotor geometry and forward flight operating conditions (i.e. advance ratio) were first examined through independent parametric studies. Next, the performance results were interpolated to determine the steady level flight characteristics of the cyclorotor, specifically the power consumption, lift-to-drag ratio and control input requirements at various forward speeds. The baseline values of lift and rotational speed for these trimmed flight studies were determined based on an existing twin-cyclorotor MAV. These studies showed the cyclorotor to be capable of achieving relatively high advance ratios (up to 0.94), with significant reductions in power consumption. In the second research approach, flow visualization experiments and time-resolved, planar particle image velocimetry (PIV) measurements were performed to gain a qualitative and quantitative understanding of the flow field. The time-averaged and phase-averaged flow fields of a 2-bladed cyclorotor were examined at different advance ratios. The PIV measurements were then correlated with previous computational fluid dynamics (CFD) simulations to help explain the distribution of forces along the rotor azimuth. The flow field studies revealed that the cyclorotor needs to operate in the counter-clockwise direction (freestream velocity from left to right) in order to produce the necessary lift force in high-speed forward flight, the primary lift and propulsive force producing regions of the cyclorotor are located in the lower-rear half of the rotor azimuth (symmetric pitching kinematics), and that unsteady aerodynamics (e.g. blade-vortex interactions) plays an important role in the generation of lift and propulsive blade force production.

Jarugumilli, Tejaswi

340

78 FR 34911 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Low Emission Vehicle...  

Federal Register 2010, 2011, 2012, 2013

...incorporates by reference California's second generation Low Emission Vehicle (LEVII) program...reduce emissions of nitrogen oxide (NO X ) and volatile organic compound...Maryland has adopted California's second generation of LEV program rules, or LEV II,...

2013-06-11

341

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

342

78 FR 9623 - Federal Motor Vehicle Safety Standards; Air Brake Systems  

Federal Register 2010, 2011, 2012, 2013

...the stopping distance data that EMA listed in Appendix...requirement. Vehicle B test data was only provided at...were conducted, EMA's data does not show how...term ``PFC'' (peak coefficient of friction) from the 0.9...

2013-02-11

343

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

Federal Register 2010, 2011, 2012, 2013

...telephone Francisco J. Acevedo, Environmental Protection Specialist, at...Francisco J. Acevedo, Environmental Protection Specialist, Control...Programs Branch (AR-18J), Environmental Protection Agency, Region...trucks have been inspected by scanning the vehicle's...

2013-04-25

344

78 FR 68378 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Amendments to Vehicle...  

Federal Register 2010, 2011, 2012, 2013

...gov or in hard copy at the Environmental Protection Agency, Region...Programs Branch (AR- 18J), Environmental Protection Agency, Region...inspected all vehicles by scanning the on-board diagnostics...disproportionate human health or environmental effects, using...

2013-11-14

345

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

346

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

347

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

348

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

349

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

350

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

351

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

352

[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

353

A complete passive or imaging-based sensor system for unmanned air vehicle taking off and landing operations  

NASA Astrophysics Data System (ADS)

We have successfully developed an innovative, miniaturized, and lightweight PTZ UCAV imager called OmniBird for unmanned air vehicle taking off and landing operations. OmniBird is developed through a SBIR funding from NAVAIR. It is to fit in 8 in 3. The designed zoom capability allows it to acquire focused images for targets ranging from 10 to 250 feet. The innovative panning mechanism also allows the system to have a field of view of +/- 100 degrees. Initial test results show that the integrated optics, camera sensor, and mechanics solution allow the OmniBird to stay optically aligned and shock-proof under harsh environments.

Yi, Steven

2008-04-01

354

Experimental and predicted pressure and heating distributions for an Aeroassist Flight Experiment vehicle in air at Mach 10  

NASA Technical Reports Server (NTRS)

The Aeroassisted Flight Experiment vehicle for whose scale model pressure and heat-transfer rate distributions have been measured in air at Mach 10 is a 60-deg elliptic cone, raked off at a 73-percent angle, with an ellipsoid nose and a skirt added to the base of the rake plane to reduce heating. The predictions of both an inviscid flow-field code and a Navier-Stokes solver are compared with measured values. Good agreement is obtained in the case of pressure distributions; the effect of Reynolds number on heat-transfer distributions is noted to be small.

Micol, John R.

1989-01-01

355

Effect of Lime Stabilized Soil Cushion on Strength Behaviour of Expansive Soil  

Microsoft Academic Search

An experimental investigation was undertaken to study the effects of lime-stabilized soil-cushion on the strength behavior\\u000a of expansive soil. In the present investigation, a series of laboratory tests (Unconfined compression tests and CBR tests)\\u000a were conducted on both expansive soil alone and expansive soil cushioned with lime-stabilized non-expansive cohesive soil.\\u000a Lime contents of 2, 4, 6, 8 and 10% by

Jagadish Prasad Sahoo; Pradip Kumar Pradhan

2010-01-01

356

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.

357

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

358

Special problems and capabilities of high altitude lighter than air vehicles  

NASA Technical Reports Server (NTRS)

Powered LTA vehicles have historically been limited to operations at low altitudes. Conditions exist which may enable a remotely piloted unit to be operated at an altitude near 70,000 feet. Such systems will be launched like high altitude balloons, operate like nonrigid airships, and have mission capabilities comparable to a low altitude stationary satellite. The limited lift available and the stratospheric environment impose special requirements on power systems, hull materials and payloads. Potential nonmilitary uses of the vehicle include communications relay, environmental monitoring and ship traffic control.

Wessel, P. R.; Petrone, F. J.

1975-01-01

359

Ozone variations through vehicle emissions reductions based on air quality monitoring data in Taipei City, Taiwan, from 1994 to 2003  

NASA Astrophysics Data System (ADS)

The ozone (O 3) ambient air quality is evaluated using two indices in Taiwan: the daily maximum O 3 concentration (O 3, max ) greater than 120 ppb and the daily 8-h O 3 moving average (O 3, 8 h ) greater than 60 ppb. Results of air quality monitoring data from 1994 to 2003 in Taipei City indicate that the 99th percentile O 3, max was reduced, but those below the 90th percentile O 3, max obviously increased and days with O 3, 8 h greater than 60 ppb were doubled after the reduction of O 3 precursor emissions. Because of Taipei's unique vehicle emissions pattern in having more motorcycles than cars, Sunday, as compared to weekdays, has more reductions of non-methane hydrocarbons (NMHCs) than NO X. This results in Sunday O 3, max being lower than weekday O 3, max average for those days with O 3, max exceeding 80 ppb. On the contrary, if O 3, max is lower than 60 ppb, Sunday O 3, max is relatively higher than weekday O 3, max average, due to the reduced NO titration effect. In addition, our evaluations of O 3 levels with respect to the ambient air quality standards show that the number of Sundays with O 3, max greater than 120 ppb is fewer than the number average of weekdays with O 3, max exceeding 120 ppb for every month. Concerning O 3, 8 h , only in June, July, and August, when the meteorological conditions favor O 3 production, does the reduction of Sunday vehicle exhaust reduce the number of days with O 3,8h greater than 60 ppb. However, in September and October, the reduction of Sunday vehicle exhaust will increase the number of days. The results presented in this paper indicate that the O 3 pollution in Taipei City is VOC-limited. Thus, for a greater reduction in NMHCs, like the Sunday vehicle reduction in Taipei City, the upper percentile O 3, max is reduced more and those below the moderately high percentile O 3, max are increased less.

Chang, Shuenn-Chin; Lee, Chung-Te

360

Novel operation and control of an electric vehicle aluminum\\/air battery system  

Microsoft Academic Search

The objective of this paper is to create a method to size battery subsystems for an electric vehicle to optimize battery performance. Optimization of performance includes minimizing corrosion by operating at a constant current density. These subsystems will allow for easy mechanical recharging. A proper choice of battery subsystem will allow for longer battery life, greater range and performance. For

Xin Zhang; Shao Hua Yang; Harold Knickle

2004-01-01

361

75 FR 15620 - Federal Motor Vehicle Safety Standards; Air Brake Systems  

Federal Register 2010, 2011, 2012, 2013

...Safety Administration 49 CFR Part 571 [Docket No. NHTSA 2009-0175...Jersey Avenue, SE., West Building, Washington, DC 20590. SUPPLEMENTARY...List of Subjects in 49 CFR Part 571 Imports, Motor vehicle safety...0 Accordingly, 49 CFR part 571 is corrected by making the...

2010-03-30

362

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...

363

Air  

MedlinePLUS

... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

364

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

365

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

366

A Small SemiAutonomous Rotary-Wing Unmanned Air Vehicle (UAV)  

Microsoft Academic Search

Small radio controlled (R\\/C) rotary-wing UAVs have many potential military and civilian applications, but can be very difficult to fly. Small and lightweight sensors and computers can be used to implement a control system to make these vehicles easier to fly. To develop a control system for a small UAV, an 8-bit microcontroller has been interfaced with MEMS (Micro-Electro-Mechanical Systems)

Scott D. Hanford; Lyle N. Long; Joseph F. Horn

2005-01-01

367

System modeling of an air-independent solid oxide fuel cell system for unmanned undersea vehicles  

Microsoft Academic Search

To examine the feasibility of a solid oxide fuel cell (SOFC)-powered unmanned undersea vehicle (UUV), a system level analysis is presented that projects a possible integration of the SOFC stack, fuel steam reformer, fuel\\/oxidant storage and balance of plant components into a 21-in. diameter UUV platform. Heavy hydrocarbon fuel (dodecane) and liquid oxygen (LOX) are chosen as the preferred reactants.

A. Alan Burke; Louis G. Carreiro

2006-01-01

368

Visual Servoing of Quadrotor Micro-Air Vehicle Using Color-Based Tracking Algorithm  

Microsoft Academic Search

This paper describes a vision-based tracking system using an autonomous Quadrotor Unmanned Micro-Aerial Vehicle (MAV). The vision-based control system relies on color target detection and tracking algorithm using integral image, Kalman filters for relative pose estimation, and a nonlinear controller for the MAV stabilization and guidance. The vision algorithm relies on information from a single onboard camera. An arbitrary target

Syaril Azrad; Farid Kendoul; Kenzo Nonami

2010-01-01

369

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

370

Analysis of Aluminum-Air Battery Propulsion Systems for Passenger Vehicles.  

National Technical Information Service (NTIS)

The performance characteristics of three electric-propulsion systems based on the Al-air battery were analyzed and compared to the internal combustion engine (ICE). Battery characteristics projected from late 1979 and early 1980 experimental results were ...

J. D. Salisbury, E. Behrin

1980-01-01

371

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

Federal Register 2010, 2011, 2012, 2013

...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

372

75 FR 51521 - Federal Motor Vehicle Safety Standards; Air Brake Systems; Technical Report on the Effectiveness...  

Federal Register 2010, 2011, 2012, 2013

...Standards; Air Brake Systems; Technical Report on the Effectiveness of Antilock...ACTION: Request for comments on technical report...announces NHTSA's publication of a Technical Report its existing Safety...

2010-08-20

373

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

374

Weight and volume estimates for aluminum-air batteries designed for electric vehicle applications  

Microsoft Academic Search

The weights and volumes of reactants, electrolyte, and hardware components are estimated for an aluminum-air battery designed for a 40-kW (peak), 70-kWh aluminum-air battery. Generalized equations are derived which express battery power and energy content as functions of total anode area, aluminum-anode weight, and discharge current density. Equations are also presented which express total battery weight and volume as linear

J. F. Cooper

1980-01-01

375

Inflorescences of alpine cushion plants freeze autonomously and may survive subzero temperatures by supercooling  

PubMed Central

Freezing patterns in the high alpine cushion plants Saxifraga bryoides, Saxifraga caesia, Saxifraga moschata and Silene acaulis were studied by infrared thermography at three reproductive stages (bud, anthesis, fruit development). The single reproductive shoots of a cushion froze independently in all four species at every reproductive stage. Ice formation caused lethal damage to the respective inflorescence. After ice nucleation, which occurred mainly in the stalk or the base of the reproductive shoot, ice propagated throughout that entire shoot, but not into neighboring shoots. However, anatomical ice barriers within cushions were not detected. The naturally occurring temperature gradient within the cushion appeared to interrupt ice propagation thermally. Consequently, every reproductive shoot needed an autonomous ice nucleation event to initiate freezing. Ice nucleation was not only influenced by minimum temperatures but also by the duration of exposure. At moderate subzero exposure temperatures (?4.3 to ?7.7 °C) the number of frozen inflorescences increased exponentially. Due to efficient supercooling, single reproductive shoots remained unfrozen down to ?17.4 °C (cooling rate 6 K h?1). Hence, the observed freezing pattern may be advantageous for frost survival of individual inflorescences and reproductive success of high alpine cushion plants, when during episodic summer frosts damage can be avoided by supercooling. PMID:21151351

Hacker, Jürgen; Ladinig, Ursula; Wagner, Johanna; Neuner, Gilbert

2011-01-01

376

Inflorescences of alpine cushion plants freeze autonomously and may survive subzero temperatures by supercooling.  

PubMed

Freezing patterns in the high alpine cushion plants Saxifraga bryoides, Saxifraga caesia, Saxifraga moschata and Silene acaulis were studied by infrared thermography at three reproductive stages (bud, anthesis, fruit development). The single reproductive shoots of a cushion froze independently in all four species at every reproductive stage. Ice formation caused lethal damage to the respective inflorescence. After ice nucleation, which occurred mainly in the stalk or the base of the reproductive shoot, ice propagated throughout that entire shoot, but not into neighboring shoots. However, anatomical ice barriers within cushions were not detected. The naturally occurring temperature gradient within the cushion appeared to interrupt ice propagation thermally. Consequently, every reproductive shoot needed an autonomous ice nucleation event to initiate freezing. Ice nucleation was not only influenced by minimum temperatures but also by the duration of exposure. At moderate subzero exposure temperatures (-4.3 to -7.7 °C) the number of frozen inflorescences increased exponentially. Due to efficient supercooling, single reproductive shoots remained unfrozen down to -17.4 °C (cooling rate 6 K h?¹). Hence, the observed freezing pattern may be advantageous for frost survival of individual inflorescences and reproductive success of high alpine cushion plants, when during episodic summer frosts damage can be avoided by supercooling. PMID:21151351

Hacker, Jürgen; Ladinig, Ursula; Wagner, Johanna; Neuner, Gilbert

2011-01-01

377

HSI Guidelines Outline for the Air Vehicle Control Station. Version 2  

NASA Technical Reports Server (NTRS)

This document provides guidance to the FAA and manufacturers on how to develop UAS Pilot Vehicle Interfaces to safely and effectively integrate UASs into the NAS. Preliminary guidelines are provided for Aviate, Communicate, Navigate and Avoid Hazard functions. The pilot shall have information and control capability so that pilot-UA interactions are not adverse, unfavorable, nor compromise safety. Unfavorable interactions include anomalous aircraft-pilot coupling (APC) interactions (closed loop), pilot-involved oscillations (categories I, II or III), and non-oscillatory APC events (e.g., divergence). - Human Systems Integration Pilot-Technology Interface Requirements for Command, Control, and Communications (C3)

2006-01-01

378

Cooperative route planning algorithm for unmanned air vehicles based on evolutionary computation  

NASA Astrophysics Data System (ADS)

This paper presents a method that utilizes an evolutionary computation to design a hierarchical and off-line route planner for multiple Unmanned Aerial Vehicles (UAVs) coordinated navigation in known static environments. Considering the problem of having a number of UAVs starting from different known initial locations, our approach can produce 3-D trajectories composed by a set of successive navigation points with a desirable velocity distribution along each trajectory, aiming at reaching a predetermined target location, while ensuring collision avoidance either with the environmental obstacles or with the UAVs and satisfying specific route and coordination constraints and objectives. The experiment results demonstrate the feasibility of the method.

Yan, Jiangjiang; Ding, Mingyue; Zhou, Chengping; Cai, Chao

2007-11-01

379

On the Application of Rapid Prototyping Technology for the Fabrication of Flapping Wings for Micro Air Vehicles  

NASA Astrophysics Data System (ADS)

Micro air vehicles (MAV) are a class of small uninhabited aircraft with dimensions less than 15 cm (6 in) and mass less than 500g (1.1 lbs). The aim of this research was to develop a fast, accurate, low-cost, and repeatable fabrication process for flapping MAV wings. Through the use of the RepRap Mendel open-source fused-deposition modeling (FDM) rapid prototyping machine ("3-D printer"), various wing prototypes were designed and fabricated using a bio-inspired approach. Testing of the aerodynamic performance of both real locust wings and the 3-D printed wing prototypes was performed through axial spin testing. Bending stiffness measurements were also performed on the 3-D printed wings. Through the use of open-source rapid prototyping technology, a fast and low-cost fabrication process for flapping MAV wings has been developed, out of which further understanding of flapping wing design and fabrication has been gained.

Kraemer, Kurtis Leigh

380

Unusual basal skull fracture in a vehicle equipped with an air bag.  

PubMed

A woman who was the lap/shoulder belt-restrained driver of a car equipped with a full-size air bag was involved in an oblique frontal collision with a tractor-trailer combination. She was extremely out of position, i.e., witnessed to be slumped over the steering wheel before impact. This preimpact positioning led to fatal injuries resulting from the inflating air bag. Postmortem examination showed an unusual partial ring fracture of the base of the skull, which to the authors' knowledge has not previously been reported. PMID:11563734

Bandstra, R A; Carbone, L S

2001-09-01

381

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

382

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

383

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

384

Control system considerations for an aluminum-air battery powered electric vehicle  

Microsoft Academic Search

Basic motor controller requirements and tradeoffs between 30 cell and 60 cell aluminum air battery systems were established. A sample controller design was evolved and basic characteristics were evaluated. Advantages of a 60 cell battery system over a 30 cell were found in the areas of control system costs, weights, and efficiency.

L. E. Cox; G. V. Hassman; S. F. Post

1980-01-01

385

Control system considerations for an aluminum-air battery powered electric vehicle  

NASA Astrophysics Data System (ADS)

Basic motor controller requirements and tradeoffs between 30 cell and 60 cell aluminum air battery systems were established. A sample controller design was evolved and basic characteristics were evaluated. Advantages of a 60 cell battery system over a 30 cell were found in the areas of control system costs, weights, and efficiency.

Cox, L. E.; Hassman, G. V.; Post, S. F.

1980-05-01

386

Control system considerations for an aluminum-air battery powered electric vehicle. Final report  

Microsoft Academic Search

The study established basic motor-controller requirements and trade-offs between 30-cell and 60-cell aluminum-air battery systems. A sample controller design was evolved and basic characteristics were evaluated. Advantages of a 60-cell battery system over a 30-cell were found in the areas of control system costs, weights, and efficiency.

L. E. Cox; G. V. Hassman; S. F. Post

1980-01-01

387

Control of air pollution from new motor vehicles and new motor vehicle engines. Federal certification test results for 1993 model year  

SciTech Connect

The regulations that apply to the control of emissions from vehicles and engines, appearing in 40 CFR Part 86, set maximum allowable limits on exhaust and evaporative emission levels. The exhaust limits are applicable to gasoline-fueled and diesel light-duty vehicles (passenger cars), light-duty trucks, and heavy-duty engines, and to gasoline-fueled motorcycles. The evaporative limits are applicable to gasoline-fueled light-duty vehicles, light-duty trucks, and heavy-duty vehicles. The report contains all of the individual tests that were required by the certification procedures.

Not Available

1993-01-01

388

To cite this document: Prothin, Sebastien and Moschetta, Jean-Marc A Vectoring Thrust Coaxial Rotor for Micro Air Vehicle: Modeling, Design and Analysis. (2013) In: 21me  

E-print Network

To cite this document: Prothin, Sebastien and Moschetta, Jean-Marc A Vectoring Thrust Coaxial Rotor: staff-oatao@inp-toulouse.fr #12;A Vectoring Thrust Coaxial Rotor for Micro Air Vehicle: Modeling, Design and maneuverability. The purpose of this paper is to study a new configuration of coaxial rotor as applied to a micro

Mailhes, Corinne

389

GPS-Optimal Micro Air Vehicle Navigation in Degraded Environments* Jason T. Isaacs1, Ceridwen Magee2, Anantharaman Subbaraman1, Francois Quitin3, Kingsley Fregene2,  

E-print Network

to their lower size, weight, required power, cost and ease of deployment/maintenance, the class of UAS for radio frequency (RF) source-seeking with a single-wing rotating micro air vehicle (MAV) operating of operating in an urban canyon environment. First, Global Positioning System (GPS) localization quality can

Hespanha, João Pedro

390

Structural sandwich construction is used in many air and space vehicles, cargo containers, boats and ships. Connection of the sandwich construction component to a framework or substructure  

E-print Network

; tapered joint; tapered sandwich beam; honeycomb core. INTRODUCTION Sandwich construction is one-to-weight ratio and high bending strength. A typical sandwich beam or panel usually consists of honeycomb, foamABSTRACT Structural sandwich construction is used in many air and space vehicles, cargo containers

Vel, Senthil

391

Visual Servoing of Quadrotor Micro-Air Vehicle Using Color-Based Tracking Algorithm  

NASA Astrophysics Data System (ADS)

This paper describes a vision-based tracking system using an autonomous Quadrotor Unmanned Micro-Aerial Vehicle (MAV). The vision-based control system relies on color target detection and tracking algorithm using integral image, Kalman filters for relative pose estimation, and a nonlinear controller for the MAV stabilization and guidance. The vision algorithm relies on information from a single onboard camera. An arbitrary target can be selected in real-time from the ground control station, thereby outperforming template and learning-based approaches. Experimental results obtained from outdoor flight tests, showed that the vision-control system enabled the MAV to track and hover above the target as long as the battery is available. The target does not need to be pre-learned, or a template for detection. The results from image processing are sent to navigate a non-linear controller designed for the MAV by the researchers in our group.

Azrad, Syaril; Kendoul, Farid; Nonami, Kenzo

392

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

393

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

394

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

395

Implementation of the Rauch-Tung-Striebel smoother for sensor compatibility correction of a fixed-wing unmanned air vehicle.  

PubMed

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

396

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

397

KCP Activities Supporting the W76LEP Stress Cushions and LK3626 RTV Replacement Material Development  

SciTech Connect

The S-5370 RTV blown foam previously produced by Dow Corning is no longer commercially available. The S-5370 material has been used on all of Los Alamos National Laboratory (LANL) programs to manufacture Stress Cushions up through the W88. The Kansas City Plant (KCP) did not have a sufficient supply of S-5370 material to cover the schedule requirements for the Program. This report provides information on the numerous activities conducted at KCP involving the development of the Program Stress Cushion and replacement RTV material.

J. W. Schneider

2009-10-01

398

Vehicle emissions  

NSDL National Science Digital Library

Air pollution in the United States is a major problem; transportation plays a major role in air pollution. This informational piece, part of a series about the future of energy, provides students with data on pollution caused by vehicles. Pollutants covered include carbon monoxide, nitrogen oxide, sulfur dioxide, and lead, among others. Copyright 2005 Eisenhower National Clearinghouse

Project, Iowa P.

2004-01-01

399

Unmanned air vehicle flow separation control using dielectric barrier discharge plasma at high wind speed  

NASA Astrophysics Data System (ADS)

The present paper described an experimental investigation of separation control of an Unmanned Aerial Vehicle (UAV) at high wind speeds. The plasma actuator was based on Dielectric Barrier Discharge (DBD) and operated in a steady manner. The flow over a wing of UAV was performed with smoke flow visualization in the ?0.75 m low speed wind tunnel to reveal the flow structure over the wing so that the locations of plasma actuators could be optimized. A full model of the UAV was experimentally investigated in the ?3.2 m low speed wind tunnel using a six-component internal strain gauge balance. The effects of the key parameters, including the locations of the plasma actuators, the applied voltage amplitude and the operating frequency, were obtained. The whole test model was made of aluminium and acted as a cathode of the actuator. The results showed that the plasma acting on the surface of UAV could obviously suppress the boundary layer separation and reduce the model vibration at the high wind speeds. It was found that the maximum lift coefficient of the UAV was increased by 2.5% and the lift/drag ratio was increased by about 80% at the wind speed of 100 m/s. The control mechanism of the plasma actuator at the test configuration was also analyzed.

Zhang, Xin; Huang, Yong; Wang, WanBo; Wang, XunNian; Li, HuaXing

2014-06-01

400

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

401

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

402

BATMAV: a biologically inspired micro air vehicle for flapping flight: kinematic modeling  

NASA Astrophysics Data System (ADS)

The overall objective of the BATMAV project is the development of a biologically inspired bat-like Micro-Aerial Vehicle (MAV) with flexible and foldable wings, capable of flapping flight. This first phase of the project focuses particularly on the kinematical analysis of the wing motion in order to build an artificial-muscle-driven actuation system in the future. While flapping flight in MAV has been previously studied and a number of models were realized using light-weight nature-inspired rigid wings, this paper presents a first model for a platform that features bat-inspired wings with a number of flexible joints which allows mimicking the kinematics of the real flyer. The bat was chosen after an extensive analysis of the flight physics of small birds, bats and large insects characterized by superior gust rejection and obstacle avoidance. Typical engineering parameters such as wing loading, wing beat frequency etc. were studied and it was concluded that bats are a suitable platform that can be actuated efficiently using artificial muscles. Also, due to their wing camber variation, they can operate effectively at a large range of speeds and allow remarkably maneuverable flight. In order to understand how to implement the artificial muscles on a bat-like platform, the analysis was followed by a study of bat flight kinematics. Due to their obvious complexity, only a limited number of degrees of freedom (DOF) were selected to characterize the flexible wing's stroke pattern. An extended analysis of flight styles in bats based on the data collected by Norberg and the engineering theory of robotic manipulators resulted in a 2 and 4-DOF models which managed to mimic the wingbeat cycle of the natural flyer. The results of the kinematical model can be used to optimize the lengths and the attachment locations of the wires such that enough lift, thrust and wing stroke are obtained.

Bunget, Gheorghe; Seelecke, Stefan

2008-03-01

403

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

404

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

405

STERILIZED PP\\/HMSPP CUSHION FOAMS FOR MEDICAL AND FOOD PACKAGING APPLICATIONS  

Microsoft Academic Search

Treatment with gamma radiation is becoming a common process for the sterilization of packages, mostly made of natural or synthetic plastics, used in aseptic processing of foods and pharmaceuticals. Packaging materials may be irradiated either prior or after filling; the irradiation prior to filling is usually chosen for dairy products, processed food, beverages, pharmaceuticals and medical devices. Cushion foams are

Elisabeth C. L. Cardoso; L. Filipe; C. P. Lima; Duclerc F. Parra; Ademar B. Lugão; N. R. Bueno; Eleosmar Gasparin

406

Distribution of Tardigrades within a Moss Cushion: Do Tardigrades Migrate in Response to Changing Moisture Conditions?  

Microsoft Academic Search

The distribution of tardigrades within the layers of the cushion moss Grimmia alpicola Hedwig, 1801 was investigated. The aim of this study was to determine the tardigrade species present within the moss layers during both wet and dry periods and to determine if migration occurred in response to changing moisture conditions. Samples of the moss were removed from concrete caps

Diane R. Nelson; Rebecca G. Adkins

2001-01-01

407

Slug is a direct Notch target required for initiation of cardiac cushion cellularization  

PubMed Central

Snail family proteins are key regulators of epithelial-mesenchymal transition, but their role in endothelial-to-mesenchymal transition (EMT) is less well studied. We show that Slug, a Snail family member, is expressed by a subset of endothelial cells as well as mesenchymal cells of the atrioventricular canal and outflow tract during cardiac cushion morphogenesis. Slug deficiency results in impaired cellularization of the cardiac cushion at embryonic day (E)–9.5 but is compensated by increased Snail expression at E10.5, which restores cardiac cushion EMT. We further demonstrate that Slug, but not Snail, is directly up-regulated by Notch in endothelial cells and that Slug expression is required for Notch-mediated repression of the vascular endothelial cadherin promoter and for promoting migration of transformed endothelial cells. In contrast, transforming growth factor ? (TGF-?) induces Snail but not Slug. Interestingly, activation of Notch in the context of TGF-? stimulation results in synergistic up-regulation of Snail in endothelial cells. Collectively, our data suggest that combined expression of Slug and Snail is required for EMT in cardiac cushion morphogenesis. PMID:18663143

Niessen, Kyle; Fu, YangXin; Chang, Linda; Hoodless, Pamela A.; McFadden, Deborah; Karsan, Aly

2008-01-01

408

Slug is a direct Notch target required for initiation of cardiac cushion cellularization.  

PubMed

Snail family proteins are key regulators of epithelial-mesenchymal transition, but their role in endothelial-to-mesenchymal transition (EMT) is less well studied. We show that Slug, a Snail family member, is expressed by a subset of endothelial cells as well as mesenchymal cells of the atrioventricular canal and outflow tract during cardiac cushion morphogenesis. Slug deficiency results in impaired cellularization of the cardiac cushion at embryonic day (E)-9.5 but is compensated by increased Snail expression at E10.5, which restores cardiac cushion EMT. We further demonstrate that Slug, but not Snail, is directly up-regulated by Notch in endothelial cells and that Slug expression is required for Notch-mediated repression of the vascular endothelial cadherin promoter and for promoting migration of transformed endothelial cells. In contrast, transforming growth factor beta (TGF-beta) induces Snail but not Slug. Interestingly, activation of Notch in the context of TGF-beta stimulation results in synergistic up-regulation of Snail in endothelial cells. Collectively, our data suggest that combined expression of Slug and Snail is required for EMT in cardiac cushion morphogenesis. PMID:18663143

Niessen, Kyle; Fu, YangXin; Chang, Linda; Hoodless, Pamela A; McFadden, Deborah; Karsan, Aly

2008-07-28

409

Oldenburg and Pan CO2 as Cushion Gas for CAES 1  

E-print Network

and Pan CO2 as Cushion Gas for CAES 9 The TOUGH Codes · TOUGH: Transport Of Unsaturated Groundwater operated at the Homestake mine from 1928-1961. Recover Heat of Compression (From Bullough et al., 2004) #12://www.isepa.com/about_isep.asp Aquifers Caverns · Pore space (porosity) · Permeability · Two-phase flow ­ Capillary forces (wetting phase

Eisen, Michael

410

Pin Cushion Plasmonic Device for Polarization Beam Splitting, Focusing, and Beam Position Estimation  

E-print Network

Pin Cushion Plasmonic Device for Polarization Beam Splitting, Focusing, and Beam Position, Jerusalem, 91904, Israel *S Supporting Information ABSTRACT: Great hopes rest on surface plasmon polaritons as a miniaturized plasmonic version of the well-known four quadrant detector. Additional potential applications may

Levy, Uriel

411

LPV H-infinity Control for the Longitudinal Dynamics of a Flexible Air-Breathing Hypersonic Vehicle  

NASA Astrophysics Data System (ADS)

This dissertation establishes the method needed to synthesize and simulate an Hinfinity Linear Parameter-Varying (LPV) controller for a flexible air-breathing hypersonic vehicle model. A study was conducted to gain the understanding of the elastic effects on the open loop system. It was determined that three modes of vibration would be suitable for the hypersonic vehicle model. It was also discovered from the open loop study that there is strong coupling in the hypersonic vehicle states, especially between the angle of attack, pitch rate, pitch attitude, and the exible modes of the vehicle. This dissertation outlines the procedure for synthesizing a full state feedback Hinfinity LPV controller for the hypersonic vehicle. The full state feedback study looked at both velocity and altitude tracking for the exible vehicle. A parametric study was conducted on each of these controllers to see the effects of changing the number of gridding points in the parameter space and changing the parameter variation rate limits in the system on the robust performance of the controller. As a result of the parametric study, a 7 x 7 grid ranging from Mach 7 to Mach 9 in velocity and from 70,000 feet to 90,000 feet in altitude, and a parameter variation rate limit of [.5 200]T was used for both the velocity tracking and altitude tracking cases. The resulting Hinfinity robust performances were gamma = 2.2224 for the velocity tracking case and = 1:7582 for the altitude tracking case. A linear analysis was then conducted on five different selected trim points from the Hinfinity LPV controller. This was conducted for the velocity tracking and altitude tracking cases. The results of linear analysis show that there is a slight difference in the response of the Hinfinity LPV controller and the fixed point H infinity controller. For the tracking task, the Hinfinity controller responds more quickly, and has a lower Hinfinity performance value. Next, the H infinity LPV controller was simulated using the nonlinear flexible hypersonic model for both the velocity tracking and altitude tracking cases. Both of these cases were subject to a ramp input and a multi-step input both with and without perturbation in the model. The results of the simulation show that the tracking state follows the command signal successfully though the perturbed system does show some higher frequency characteristics in the non-tracking states. It was discovered that there is an issue with integral windup when switching takes place in the controller, so an algorithm was implemented to reset the integration of the error on the tracking state when the switch takes place. It was also seen that there was a decline in altitude when tracking velocity, and a large change in velocity that occurred during altitude tracking. These results lead to the decision to include a unity gain regulation state on velocity for the altitude tracking and the altitude for the velocity tracking during the output feedback control synthesis. The procedure for synthesizing an output feedback H infinity LPV controller for the hypersonic vehicle is also discussed in this dissertation. The output feedback design looked at velocity tracking and altitude tracking with rigid body motion variables for both the exible and rigid body hypersonic vehicle models. As with the full state feedback controller, a parametric study was conducted on each of these controllers to determine the number of gridding points in the parameter space and the parameter variation rate limits in the system. The parametric study reveals a 7x7 grid ranging from Mach 7 to Mach 9 in velocity and from 70,000 feet to 90,000 feet in altitude, and a parameter variation rate limit of [.1 200]T is preferable for both the velocity tracking and altitude tracking cases with both the exible and rigid body assumptions. The resulting Hinfinity robust performances were gamma = 113:2146 for the exible body velocity tracking case, gamma = 83.6931 for the rigid body velocity tracking case, gamma = 107:2043 for the exible body altitude tracking case, and gamma = 9

Hughes, Hunter Douglas

412

Aerodynamics of road vehicles  

SciTech Connect

This introduction to aerodynamic aspects of motor vehicle design will be of use both to vehicle designers and students of automobile engineering. Content covers vehicle systems, ventilation and aerodynamic design to reduce drag and increase stability of cars, commercial vehicles and PSVs. Topics considered include automobile aerodynamics; some fundamentals of fluid mechanics; performance of cars and light vans; aerodynamic drag of passenger cars; driving stability in sidewinds; operation, safety and comfort; high-performance vehicle aerodynamics; commercial vehicles; engine cooling systems; heating, ventilation and air conditioning of motor vehicles; wind tunnels for automobile aerodynamics; measuring and testing techniques; and numerical methods for computation of flow around road vehicles.

Hucho, W.H.

1987-01-01

413

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

NASA Astrophysics Data System (ADS)

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 Reynolds numbers. Wind tunnel tests of wings with aspect ratios between 0.5 and 2.0, four distinct planforms, thickness-to-chord ratios of ?2%, and 5-to-1 elliptical leading edges have been conducted as part of this research. The Reynolds numbers considered were in the range of 70,000 to 200,000. Analysis of the data includes comparison of lift-curve slope, induced-drag coefficient, and maximum lift coefficient with theory, discussion of aerodynamic center, and the effects of Reynolds number, camber, and leading-edge shape. As an example of an application of this wind tunnel data, the experimental results are implemented within an aircraft performance prediction procedure. This procedure is incorporated into a genetic algorithm optimization program that identifies near-optimum MAV configurations given certain requirements and constraints. Results obtained by use of this optimization procedure have revealed that useful design tools can be developed based on the experimental database.

Torres, Gabriel Eduardo

2002-09-01

414

Commercial Motor Vehicle Brake Assessment Tools  

E-print Network

Commercial Motor Vehicle Brake Assessment Tools Commercial Motor Vehicle Roadside Technology Corridor Safety Technology Showcase October 14, 2010 Commercial Motor Vehicle Roadside Technology Corridor #12;Overview · Commercial Motor Vehicle (CMV) Air Brake System · North American Standard Level-1

415

An adaptive dual-optimal path-planning technique for unmanned air vehicles with application to solar-regenerative high altitude long endurance flight  

Microsoft Academic Search

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

Clifford A. Whitfield

2009-01-01

416

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

417

Federal certification test results for 1992 model year. Control of air pollution from new motor vehicles and new motor vehicle engines  

SciTech Connect

Each manufacturer of a passenger car, (light-duty-vehicle), light-duty truck, motorcycle, heavy-duty gasoline engine, and heavy-duty diesel engine is required to demonstrate compliance with the applicable exhaust emission standard. This report contains all of the individual tests that were required by the certification-procedures found in Title 40 of the Code of Federal Regulations in Part 86. These data were submitted to the Environmental Protection Agency's Certification Division at the National Vehicle and Fuel Emissions Laboratory.

Not Available

1992-01-01

418

The alpine cushion plant Silene acaulis as foundation species: a bug's-eye view to facilitation and microclimate.  

PubMed

Alpine ecosystems are important globally with high levels of endemic and rare species. Given that they will be highly impacted by climate change, understanding biotic factors that maintain diversity is critical. Silene acaulis is a common alpine nurse plant shown to positively influence the diversity and abundance of organisms--predominantly other plant species. The hypothesis that cushion or nurse plants in general are important to multiple trophic levels has been proposed but rarely tested. Alpine arthropod diversity is also largely understudied worldwide, and the plant-arthropod interactions reported are mostly negative, that is,. herbivory. Plant and arthropod diversity and abundance were sampled on S. acaulis and at paired adjacent microsites with other non-cushion forming vegetation present on Whistler Mountain, B.C., Canada to examine the relative trophic effects of cushion plants. Plant species richness and abundance but not Simpson's diversity index was higher on cushion microsites relative to other vegetation. Arthropod richness, abundance, and diversity were all higher on cushion microsites relative to other vegetated sites. On a microclimatic scale, S. acaulis ameliorated stressful conditions for plants and invertebrates living inside it, but the highest levels of arthropod diversity were observed on cushions with tall plant growth. Hence, alpine cushion plants can be foundation species not only for other plant species but other trophic levels, and these impacts are expressed through both direct and indirect effects associated with altered environmental conditions and localized productivity. Whilst this case study tests a limited subset of the membership of alpine animal communities, it clearly demonstrates that cushion-forming plant species are an important consideration in understanding resilience to global changes for many organisms in addition to other plants. PMID:22655035

Molenda, Olivia; Reid, Anya; Lortie, Christopher J

2012-01-01

419

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

420

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

421

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

Microsoft Academic Search

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

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

1989-01-01

422

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

Microsoft Academic Search

This neutron reflectometry study evaluates the structures resulting from different methods of preparing polymer-cushioned lipid bilayers. Four different techniques to deposit a dimyristoylphosphatidylcholine (DMPC) bilayer onto a polyethylenimine (PEI)-coated quartz substrate were examined: 1) vesicle adsorption onto a previously dried polymer layer; 2) vesicle adsorption onto a bare substrate, followed by polymer adsorption; and 3, 4) Langmuir-Blodgett vertical deposition of

J. Y. Wong; J. Majewski; M. Seitz; C. K. Park; J. N. Israelachvili; G. S. Smith

1999-01-01

423

Thrombus Formation on the Tricuspid Valve After De Vega's Annuloplasty and Repair of Endocardial Cushion Defect  

PubMed Central

Endocardial cushion defect (ECD) can be partial (with two distinct valves) or complete (only one atrioventricular valve), and surgical therapy is usually required. The optimal surgical technique is controversial but De Vega’s annuloplasty is widely performed. Tricuspid valve thrombosis are rarely seen after surgery. We present a 39-year-old male patient with tricuspid valve thrombosis after De Vega’s annuloplasty without the use of a ring. PMID:25320670

Efe, Suleyman Cagan; Unkun, Tuba; Izci, Servet; Cap, Murat; Bakal, Ruken Bengi; Acar, Rezzan Deniz; Gecmen, Cetin; Erdogan, Emrah; Ozdemir, Nihal

2014-01-01

424

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

E-print Network

Stand and Instrumentation. Test Stand The test stand as illustrated in Figure 7, 8, and 9 consists of a dropping platen, weights, anvil, electromagnet, and supporting mass. The test stand was designed basically like the apparatus shown... Manual for Model H Oscillo ra h Recorder, William Miller Instruments, Inc. , Pasadena, Calif. , 1957. 16. Janssen, R. R. , "Selecting Package Cushioning Material to Provide Minimum Container Cubage, " Report No, NA 57-884, North American Aviation...

Woolam, William Edward

2012-06-07

425

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

426

Clean Cities ozone air quality attainment and maintenance strategies that employ alternative fuel vehicles, with special emphasis on natural gas and propane  

SciTech Connect

Air quality administrators across the nation are coming under greater pressure to find new strategies for further reducing automotive generated non-methane hydrocarbon (NMHC) and nitrogen oxide (NOx) emissions. The US Environmental Protection Agency (EPA) has established stringent emission reduction requirements for ozone non-attainment areas that have driven the vehicle industry to engineer vehicles meeting dramatically tightened standards. This paper describes an interim method for including alternative-fueled vehicles (AFVs) in the mix of strategies to achieve local and regional improvements in ozone air quality. This method could be used until EPA can develop the Mobile series of emissions estimation models to include AFVs and until such time that detailed work on AFV emissions totals by air quality planners and emissions inventory builders is warranted. The paper first describes the challenges confronting almost every effort to include AFVs in targeted emissions reduction programs, but points out that within these challenges resides an opportunity. Next, it discusses some basic relationships in the formation of ambient ozone from precursor emissions. It then describes several of the salient provisions of EPA`s new voluntary emissions initiative, which is called the Voluntary Mobile Source Emissions Reduction Program (VMEP). Recent emissions test data comparing gaseous-fuel light-duty AFVs with their gasoline-fueled counterparts is examined to estimate percent emissions reductions achievable with CNG and LPG vehicles. Examples of calculated MOBILE5b emission rates that would be used for summer ozone season planning purposes by an individual Air Quality Control Region (AQCR) are provided. A method is suggested for employing these data to compute appropriate voluntary emission reduction credits where such (lighter) AFVs would be acquired. It also points out, but does not quantify, the substantial reduction credits potentially achievable by substituting gaseous-fueled for gasoline-fueled heavy-duty vehicles. Finally, it raises and expands on the relevance of AFVs and their deployment to some other provisions embedded in EPA`s current guidance for implementing 1-hour NAAQS--standards which currently remain in effect--as tools to provide immediate reductions in ozone, without waiting for promised future clean technologies.

Santini, D.J.; Saricks, C.L.

1998-08-04

427

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

428

The Air Pollution Threat.  

National Technical Information Service (NTIS)

Contents: General inventory of air pollution sources and emissions; A summary of federal, state, and local air pollution laws; The quality of air in the sacramento regional area; Projections of population, vehicles, and activities to 1990; Air quality in ...

W. L. Faith

1969-01-01

429

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

430

Can extractable organic matter (EOM) be used as a motor vehicle tracer in multivariate air quality receptor models  

SciTech Connect

Summertime data collected at two New Jersey sites during the Airborne Toxic Element and Organic Substances (ATEOS) project was used to develop a replacement tracer for Pb from motor vehicle particulate emissions. The Elizabeth and Camden, New Jersey data were analyzed using principal factor analysis (PFA) with varimax rotation and multiple regression models were developed to predict inhalable particulate (D/sub 50/less than or equal to15 ..mu..m) mass (IPM). Dichloromethane-soluble organics (DCM) proved to be the best tracer for motor vehicles in this analysis. By using DCM as a motor vehicle tracer the selected models predicted that 14-25% of IPM resulted from this source category.

Harkov, R.; Shiboski, S.

1986-01-01

431

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

432

An Innovative Approach for Data Collection and Handling to Enable Advancements in Micro Air Vehicle Persistent Surveillance  

E-print Network

.S.-European Micro-Aerial Vehicle Technology 24 Demonstration and Assessment held in Germany in 2005, was able to be programmed with GPS waypoints for navigation. In addition, the Dragonfly had built-in autonomous functionality such as climb and return....S.-European Micro-Aerial Vehicle Technology 24 Demonstration and Assessment held in Germany in 2005, was able to be programmed with GPS waypoints for navigation. In addition, the Dragonfly had built-in autonomous functionality such as climb and return...

Goodnight, Ryan David

2010-10-12

433

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

434

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

435

International Micro Air Vehicle Conference and Flight Competition (IMAV2013) 17-20 September 2013, Toulouse, France  

E-print Network

and the navigation of the aircraft. Longitdinal dynamics of the vehicle are examined by using an innovative technique in the miniaturization of the inertial instruments i.e. Inertial Navigation System (INS) and Global Positioning System (GPS) hardware have led to the design of small, low-cost integrated navigation systems. Despite all

Paris-Sud XI, Université de

436

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

437

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

438

The effect of cushioning insoles on back and lower extremity pain in an industrial setting.  

PubMed

The purpose of this study was to examine the relationship between low back pain and lower extremity pain in a group of factory workers and determine the effect of cushioning insoles on low back pain and lower extremity pain. Data were gathered via questionnaire from 306 employees of an aircraft engine assembly factory. A subset of 40 workers who had reported significant levels of back or lower extremity pain were sampled for four consecutive 12-hour shifts wearing their normal footwear and then a week later for four consecutive shifts wearing cushioning insoles. High levels of low back pain and lower extremity pain were reported by workers on the plant floor, but low back pain was poorly correlated to lower extremity pain (r = 0.371). The effect of insoles on the subset of 40 workers was to lower low back pain by 38%, foot pain by 37%, and knee pain by 38% (p < .001). The reduction in low back pain, however, was not correlated to the reduction in lower extremity pain; workers reporting a decrease in low back pain differed from those reporting less lower extremity pain. PMID:24053218

Jefferson, John R

2013-10-01

439

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

440

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; Dolezal, Jiri; Dvorsky, Miroslav; Chlumska, Zuzana; Rehakova, Klara; Klimesova, Jitka; Klimes, Leos

2011-01-01

441

Transportation and Air Quality  

MedlinePLUS

... protects public health and the environment by regulating air pollution from motor vehicles, engines, and the fuels used ... Overview: Pollutants and Programs Information on how much air pollution, air toxics, and greenhouse gases are emitted by ...

442

Advanced computer technology - An aspect of the Terminal Configured Vehicle program. [air transportation capacity, productivity, all-weather reliability and noise reduction improvements  

NASA Technical Reports Server (NTRS)

NASA is conducting a Terminal Configured Vehicle program to provide improvements in the air transportation system such as increased system capacity and productivity, increased all-weather reliability, and reduced noise. A typical jet transport has been equipped with highly flexible digital display and automatic control equipment to study operational techniques for conventional takeoff and landing aircraft. The present airborne computer capability of this aircraft employs a multiple computer simple redundancy concept. The next step is to proceed from this concept to a reconfigurable computer system which can degrade gracefully in the event of a failure, adjust critical computations to remaining capacity, and reorder itself, in the case of transients, to the highest order of redundancy and reliability.

Berkstresser, B. K.

1975-01-01

443

The Alpine Cushion Plant Silene acaulis as Foundation Species: A Bug’s-Eye View to Facilitation and Microclimate  

Microsoft Academic Search

Alpine ecosystems are important globally with high levels of endemic and rare species. Given that they will be highly impacted by climate change, understanding biotic factors that maintain diversity is critical. Silene acaulis is a common alpine nurse plant shown to positively influence the diversity and abundance of organisms–predominantly other plant species. The hypothesis that cushion or nurse plants in

Olivia Molenda; Anya Reid; Christopher J. Lortie

2012-01-01

444

Nurse plant effect of the cushion plant Silene acaulis (L.) Jacq. in an alpine environment in the subarctic Scandes, Sweden  

Microsoft Academic Search

Background: Facilitation plays important roles in the structuring of plant communities and several studies have found that it tends to increase with environmental severity in alpine plant communities. In addition, cushion plants have been shown to act as nurse plants, moderating extreme environmental conditions, and providing resources for other species, with substantial effects on local plant diversity.Aims: This study addresses

Henrik Antonsson; Robert G. Björk; Ulf Molau

2009-01-01

445

An investigation of drag reduction for tractor trailer vehicles with air deflector and boattail. [wind tunnel tests  

NASA Technical Reports Server (NTRS)

A wind tunnel investigation was conducted to determine the influence of several physical variables on the aerodynamic drag of a trailer model. The physical variables included: a cab mounted wind deflector, boattail on trailer, flow vanes on trailer front, forced transition on trailer, and decreased gap between tractor and trailer. Tests were conducted at yaw angles (relative wind angles) of 0, 5, 10, 20, and 30 degrees and Reynolds numbers of 3.58 x 10 to the 5th power 6.12 x 10 to the 5th power based upon the equivalent diameter of the vehicles. The wind deflector on top of the cab produced a calculated reduction in fuel consumption of about 5 percent of the aerodynamic portion of the fuel budget for a wind speed of 15.3 km/hr (9.5 mph) over a wind angle range of 0 deg to 180 deg and for a vehicle speed of 88.5 km/hr (55 mph). The boattail produced a calculated 7 percent to 8 percent reduction in fuel consumption under the same conditions. The decrease in gap reduced the calculated fuel consumption by about 5 percent of the aerodynamic portion of the fuel budget.

Muirhead, V. U.

1981-01-01

446

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

447

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

448

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.

449

Effect of Neutral-Cushioned Running Shoes on Plantar Pressure Loading and Comfort in Athletes With Cavus FeetA Crossover Randomized Controlled Trial  

Microsoft Academic Search

Background: High injury rates observed in athletes with cavus feet are thought to be associated with elevated plantar pressure loading. Neutral-cushioned running shoes are often recommended to manage and prevent such injuries.Purpose: To investigate in-shoe plantar pressure loading and comfort during running in 2 popular neutral-cushioned running shoes recommended for athletes with cavus feet.Study Design: Controlled laboratory study.Methods: Plantar pressures

Caleb Wegener; Joshua Burns; Stefania Penkala

2008-01-01

450

Testing the Stress-Gradient Hypothesis at the Roof of the World: Effects of the Cushion Plant Thylacospermum caespitosum on Species Assemblages  

PubMed Central

Many cushion plants ameliorate the harsh environment they inhabit in alpine ecosystems and act as nurse plants, with significantly more species growing within their canopy than outside. These facilitative interactions seem to increase with the abiotic stress, thus supporting the stress-gradient hypothesis. We tested this prediction by exploring the association pattern of vascular plants with the dominant cushion plant Thylacospermum caespitosum (Caryophyllaceae) in the arid Trans-Himalaya, where vascular plants occur at one of the highest worldwide elevational limits. We compared plant composition between 1112 pair-plots placed both inside cushions and in surrounding open areas, in communities from cold steppes to subnival zones along two elevational gradients (East Karakoram: 4850–5250 m and Little Tibet: 5350–5850 m). We used PERMANOVA to assess differences in species composition, Friedman-based permutation tests to determine individual species habitat preferences, species-area curves to assess whether interactions are size-dependent and competitive intensity and importance indices to evaluate plant-plant interactions. No indications for net facilitation were found along the elevation gradients. The open areas were not only richer in species, but not a single species preferred to grow exclusively inside cushions, while 39–60% of 56 species detected had a significant preference for the habitat outside cushions. Across the entire elevation range of T. caespitosum, the number and abundance of species were greater outside cushions, suggesting that competitive rather than facilitative interactions prevail. This was supported by lower soil nutrient contents inside cushions, indicating a resource preemption, and little thermal amelioration at the extreme end of the elevational gradient. We attribute the negative associations to competition for limited resources, a strong environmental filter in arid high-mountain environment selecting the stress-tolerant species that do not rely on help from other plants during their life cycle and to the fact the cushions do not provide a better microhabitat to grow in. PMID:23326446

Dvorsky, Miroslav; Dolezal, Jiri; Kopecky, Martin; Chlumska, Zuzana; Janatkova, Katerina; Altman, Jan; de Bello, Francesco; Rehakova, Klara

2013-01-01

451

Impact of increased vehicle emissions on the ozone concentrations around beach areas in summer using air quality modeling system  

NASA Astrophysics Data System (ADS)

The impact of pollutant emissions by the huge amount of road traffic around beaches on the ozone (O3) concentrations in the surrounding regions were evaluated using a numerical modeling approach during the beach opening period (BOP) (July to August). This analysis was performed based on two simulation conditions: 1) with mobile emissions during the BOP (i.e. BOP case); and 2) during the normal period (i.e. NOR case). On-road mobile emissions were estimated from the emission factors, vehicle kilometers traveled, and deterioration factors at several roads close to beaches in Busan, Korea during a 4-day observation period (29 and 31 July and 1 and 3 August) of the BOP in 2010. The emission data was then applied to the 3-D chemical transport model (i.e. the WRF-CMAQ modeling system). A process analysis (PA) was also used to assess the contributions of the individual physical and chemical processes to the production or loss of O3 in the study area. The model study suggested the possibility that road traffic emissions near the beach area can have a direct impact on the O3 concentrations in the source regions as well as their surrounding/downwind regions. The maximum negative impact of mobile emissions on the O3 concentrations between the BOP and NOR cases was predicted near the beach areas: by -4 ppb during the day due to the high NOx emissions with the high NOx/VOC ratio and -8 ppb during the late evening due to the fast titration of O3 by NO. The PA showed that the rate of O3 destruction due to the road traffic emissions around the beach areas decreased by -2.3 (weekend, 31 July) and -5.5 ppb h-1 (weekday, 3 August) during the day. Acknowledgments: This work was funded by the Korea Meteorological Administration Research and Development Program under Grant CATER_2012-6140. This work was also funded by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0021141).

Song, S.; Kim, Y.; Shon, Z.; Kang, Y.; Jeong, J.

2012-12-01

452