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Sample records for air film thrust

  1. Theoretical Analysis and Optimum Design of High Speed Air Film Thrust Bearings

    NASA Astrophysics Data System (ADS)

    Hashimoto, Hiromu; Ochiai, Masayuki; Nanba, Tadashi

    Hydrodynamic air film thrust bearings are widely used for very high speed, lightly loaded rotating machinery such as gas expander, compressor, gyroscope and business machines, etc. In the design of hydrodynamic air film thrust bearings, it is of cardinal importance to enhance the friction and stability capacities of air films for keeping the minimum friction loss within a particular level and for minimizing the vibration due to external excitations. Among various types of hydrodynamic air film thrust bearings, spiral and herring bone types of grooved bearings have an advantage of high stability and load carrying capacity, but the characteristics of the bearings depend on many design parameters. Therefore, when these parameters are designed suitably, it is expected to improve considerably the friction and stability characteristics of the bearings. In this paper, the optimum design methodology is presented to minimize the friction torque and also to maximize the stiffness of air film for spiral and herring bone types of grooved air film thrust bearings, and the applicability of the methodology is verified experimentally.

  2. Performance of Simple Gas Foil Thrust Bearings in Air

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.

    2012-01-01

    Foil bearings are self-acting hydrodynamics devices used to support high speed rotating machinery. The advantages that they offer to process fluid lubricated machines include: high rotational speed capability, no auxiliary lubrication system, non-contacting high speed operation, and improved damping as compared to rigid hydrodynamic bearings. NASA has had a sporadic research program in this technology for almost 6 decades. Advances in the technology and understanding of foil journal bearings have enabled several new commercial products in recent years. These products include oil-free turbochargers for both heavy trucks and automobiles, high speed electric motors, microturbines for distributed power generation, and turbojet engines. However, the foil thrust bearing has not received a complimentary level of research and therefore has become the weak link of oil-free turbomachinery. In an effort to both provide machine designers with basic performance parameters and to elucidate the underlying physics of foil thrust bearings, NASA Glenn Research Center has completed an effort to experimentally measure the performance of simple gas foil thrust bearing in air. The database includes simple bump foil supported thrust bearings with full geometry and manufacturing techniques available to the user. Test conditions consist of air at ambient pressure and temperatures up to 500 C and rotational speeds to 55,000 rpm. A complete set of axial load, frictional torque, and rotational speed is presented for two different compliant sub-structures and inter-pad gaps. Data obtained from commercially available foil thrust bearings both with and without active cooling is presented for comparison. A significant observation made possible by this data set is the speed-load capacity characteristic of foil thrust bearings. Whereas for the foil journal bearing the load capacity increases linearly with rotational speed, the foil thrust bearing operates in the hydrodynamic high speed limit. In

  3. Theoretical Analysis and Optimum Design of High Speed Gas Film Thrust Bearings

    NASA Astrophysics Data System (ADS)

    Hashimoto, Hiromu; Ochiai, Masayuki

    This paper describes the theoretical and experimental investigations of static and dynamic characteristics of four types of high-speed gas film thrust bearings, such as stepped, pocketed, spiral and herring bone grooved bearings. The specially designed test rig is used to measure the air film thickness, friction torque, spring and damping coefficients of air film under the high speed operation conditions from 20000 rpm to 40000 rpm. It is verified that the maximum error in the measurements by the present test rig is less than 7 percent. On the other hand, the measured results are compared with the theoretical results for checking the applicability of numerical analysis method to bearing design. Good agreements are seen between the measured results and theoretical predictions, and applicability of theoretical prediction method is confirmed with experimental verifications.

  4. Compact and High Thrust Air Turbo Ram Engine

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroaki; Kitahara, Kazuki; Inukai, Yasuo

    The Air Turbo Ramjet (ATR) is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds and therefore the ATR is an attractive propulsion system for the wide operation range (e.g. Mach 0 to Mach 4). The ATR can provide a higher specific impulse than a solid fuel rocket engine and a higher thrust per frontal area than a turbojet engine. The major ATR components are the inlet, fan (compressor), turbine, gas generator, combustor and exhaust nozzle. In the ATR, the turbine drive gas is generated by a decomposed liquid or solid fuel gas generator. In order to carry heavier payloads and to attain shorter flight time, the compact and high thrust engine is required. In this study, the ram combustor with the double-staged flameholders and the fan with tandem blade were introduced to shorten the engine length and to increase the fan pressure ratio, respectively. Furthermore, the engine testing was carried out on sea level static condition to confirm the engine component integration technologies for the ATR propulsion system.

  5. Start-stop testing of two self-acting air-lubricated spiral groove thrust bearing coatings

    NASA Technical Reports Server (NTRS)

    Dunfee, J. D.; Shapiro, W.

    1974-01-01

    Start-stop tests were conducted on air-lubricated spiral-groove thrust bearings. Application of a matrix-bonded molybdenum disulfide (MoS2) coating over a porous chrome oxide coating resulted in significantly lower friction, compared to bearings coated with chrome oxide only. The MoS2 coated bearing sustained 15,000 start-stop cycles at a maximum of 3600 rpm. Each cycle was 15 seconds on, 30 seconds off. The chrome oxide coated bearing failed by local welding after 2030 cycles. Both types of coatings exhibited early failures under higher thrust loads when operating films were insufficient to sustain the load without overheating.

  6. Effects of bleed air extraction on thrust levels on the F404-GE-400 turbofan engine

    NASA Technical Reports Server (NTRS)

    Yuhas, Andrew J.; Ray, Ronald J.

    1992-01-01

    A ground test was performed to determine the effects of compressor bleed flow extraction on the performance of F404-GE-400 afterburning turbofan engines. The two engines were installed in the F/A-18 High Alpha Research Vehicle at the NASA Dryden Flight Research Facility. A specialized bleed ducting system was installed onto the aircraft to control and measure engine bleed airflow while the aircraft was tied down to a thrust measuring stand. The test was conducted on each engine and at various power settings. The bleed air extraction levels analyzed included flow rates above the manufacturer's maximum specification limit. The measured relationship between thrust and bleed flow extraction was shown to be essentially linear at all power settings with an increase in bleed flow causing a corresponding decrease in thrust. A comparison with the F404-GE-400 steady-state engine simulation showed the estimation to be within +/- 1 percent of measured thrust losses for large increases in bleed flow rate.

  7. A piloted simulation investigation of the normal load factor and longitudinal thrust required for air-to-air acquisition and tracking

    NASA Technical Reports Server (NTRS)

    Whalley, Matthew S.

    1993-01-01

    A piloted simulation study was performed by the U.S. Army Aeroflighydynamics Directorate to develop insight into the maneuverability requirements for aggressive helicopter maneuvering tasks such as air-to-air combat. Both a conventional helicopter and a helicopter with auxiliary thrust were examined. The aircraft parameters of interest were the normal and longitudinal load factor envelopes. Of particular interest were the mission performance and handling qualities tradeoffs with the parameters of interest. Two air-to-air acquisition and tracking tasks and a return-to-cover task were performed to assess mission performance. Results indicate that without auxiliary thrust, the ownship normal load factor capability needs to match that of the adversary in order to provide satisfactory handling qualities. Auxiliary thrust provides significant handling qualities advantages and can be substituted to some extent for normal load factor capability. Auxiliary thrust levels as low as 0.2 thrust/weight can provide significant handling qualities advantages.

  8. Determination of thermal load in film cooled bipropellant thrust chambers by an inverse method

    NASA Astrophysics Data System (ADS)

    Hinckel, J. N.; Savonov, R. I.; Patire, H.

    2013-03-01

    A method to obtain the heat load on the internal wall of a rocket thrust chamber using an inverse problem approach is described. According to the "classical" approach, the heat load on the internal wall of the chamber is assumed as the product of a heat transfer coefficient and the temperature difference of adiabatic wall temperature and local wall surface temperature. The time-dependent temperature distribution of the external wall of the thruster chamber is used to obtain empirical curve fittings to the temperature profile of the near wall flow field (adiabatic wall temperature) and the heat transfer coefficient profile. The applicability of the method is verified by applying it to three different problems; a model problem, an analytical solution, and a set of experimental data.

  9. Evaluation of chromium oxide and molybdenum disulfide coatings in self-acting stops of an air-lubricated Rayleigh step thrust bearing

    NASA Technical Reports Server (NTRS)

    Nemeth, Z. N.

    1974-01-01

    Two coatings for a Rayleigh step thrust bearing were tested when coasting down and stopping under self-acting operation in air. The thrust bearing had an outside diameter of 8.9 cm (3.5 in.), an inside diameter of 5.4 cm (2.1 in.), and nine sectors. The load was 73 N (16.4 lbf). The load pressure was 19.1 kN/per square meter (2.77 lbf/per square inch) on the total thrust bearing area. The chromium oxide coating was good to 150 stops without bearing deterioration, and the molybdenum disulfide coating was good for only four stops before bearing deterioration. The molybdenum disulfide coated bearing failed after nine stops.

  10. Lateral dampers for thrust bearings

    NASA Technical Reports Server (NTRS)

    Hibner, D. H.; Szafir, D. R.

    1985-01-01

    The development of lateral damping schemes for thrust bearings was examined, ranking their applicability to various engine classes, selecting the best concept for each engine class and performing an in-depth evaluation. Five major engine classes were considered: large transport, military, small general aviation, turboshaft, and non-manrated. Damper concepts developed for evaluation were: curved beam, constrained and unconstrained elastomer, hybrid boost bearing, hydraulic thrust piston, conical squeeze film, and rolling element thrust face.

  11. Development of a 12-Thrust Chamber Kerosene /Oxygen Primary Rocket Sub-System for an Early (1964) Air-Augmented Rocket Ground-Test System

    NASA Technical Reports Server (NTRS)

    Pryor, D.; Hyde, E. H.; Escher, W. J. D.

    1999-01-01

    Airbreathing/Rocket combined-cycle, and specifically rocket-based combined- cycle (RBCC), propulsion systems, typically employ an internal engine flow-path installed primary rocket subsystem. To achieve acceptably short mixing lengths in effecting the "air augmentation" process, a large rocket-exhaust/air interfacial mixing surface is needed. This leads, in some engine design concepts, to a "cluster" of small rocket units, suitably arrayed in the flowpath. To support an early (1964) subscale ground-test of a specific RBCC concept, such a 12-rocket cluster was developed by NASA's Marshall Space Flight Center (MSFC). The small primary rockets used in the cluster assembly were modified versions of an existing small kerosene/oxygen water-cooled rocket engine unit routinely tested at MSFC. Following individual thrust-chamber tests and overall subsystem qualification testing, the cluster assembly was installed at the U. S. Air Force's Arnold Engineering Development Center (AEDC) for RBCC systems testing. (The results of the special air-augmented rocket testing are not covered here.) While this project was eventually successfully completed, a number of hardware integration problems were met, leading to catastrophic thrust chamber failures. The principal "lessons learned" in conducting this early primary rocket subsystem experimental effort are documented here as a basic knowledge-base contribution for the benefit of today's RBCC research and development community.

  12. Porous Mg thin films for Mg-air batteries.

    PubMed

    Xin, Gongbiao; Wang, Xiaojuan; Wang, Chongyun; Zheng, Jie; Li, Xingguo

    2013-12-28

    An alkaline primary Mg-air battery made from a porous Mg thin film displayed superior discharge performances, including a flat discharge plateau, a high open-circuit voltage of 1.41 V and a large discharge capacity of 821 mAh g(-1), suggesting that the electrochemical performances of Mg-air batteries can be improved by controlling the Mg anode morphology. PMID:24158667

  13. Abdominal thrusts

    MedlinePlus

    ... call 911 . If the person loses consciousness, start CPR . If you are not comfortable performing abdominal thrusts, ... American Red Cross. First Aid/CPR/AED Participant's Manual. 2nd ... Red Cross; 2014. Berg RA, Hemphill R, Abella BS, et al. Part 5: ...

  14. Cylindrical PVDF film transmitters and receivers for air ultrasound.

    PubMed

    Toda, Minoru

    2002-05-01

    Cylindrical polyvinylidene fluoride (PVDF) film transducers for transmission and reception of 40-kHz ultrasonic waves in air have been investigated. A key feature of such transducers is their omni-directional polar response. An optimized structure comprises a cylindrical PVDF film element resting on a spool without a mechanical bond to it. Various key design equations to obtain the required ultrasonic performance both as transmitter and receiver are shown, which include resonance frequency, acoustic pressure, angle performance, back air cavity effect, and receiver sensitivity. Measurements of actual frequency response of transmitter output and receiver sensitivity, angular performance, back air space effect, and temperature effect are presented. The results agree well with the theoretical predictions. It has been shown that this device is well-suited for practical application as an ultrasonic ranging device. PMID:12046938

  15. THRUST BEARING

    DOEpatents

    Heller, P.R.

    1958-09-16

    A thrust bearing suitable for use with a rotor or blower that is to rotate about a vertical axis is descrihed. A centrifagal jack is provided so thnt the device may opernte on one hearing at starting and lower speeds, and transfer the load to another bearing at higher speeds. A low viscosity fluid is used to lubricate the higher speed operation bearing, in connection with broad hearing -surfaces, the ability to withstand great loads, and a relatively high friction loss, as contraated to the lower speed operatio;n bearing which will withstand only light thrust loads but is sufficiently frictionfree to avoid bearing seizure during slow speed or startup operation. An axially aligned shaft pin provides the bearing surface for low rotational speeds, but at higher speed, weights operating against spring tension withdraw nthe shaft pin into the bearing proper and the rotor shaft comes in contact with the large bearing surfaces.

  16. Design and evaluation of thrust vectored nozzles using a multicomponent thrust stand

    NASA Technical Reports Server (NTRS)

    Carpenter, Thomas W.; Blattner, Ernest W.; Stagner, Robert E.; Contreras, Juanita; Lencioni, Dennis; Mcintosh, Greg

    1990-01-01

    Future aircraft with the capability of short takeoff and landing, and improved maneuverability especially in the post-stall flight regime will incorporate exhaust nozzles which can be thrust vectored. In order to conduct thrust vector research in the Mechanical Engineering Department at Cal Poly, a program was planned with two objectives; design and construct a multicomponent thrust stand for the specific purpose of measuring nozzle thrust vectors; and to provide quality low moisture air to the thrust stand for cold flow nozzle tests. The design and fabrication of the six-component thrust stand was completed. Detailed evaluation tests of the thrust stand will continue upon the receipt of one signal conditioning option (-702) for the Fluke Data Acquisition System. Preliminary design of thrust nozzles with air supply plenums were completed. The air supply was analyzed with regard to head loss. Initial flow visualization tests were conducted using dual water jets.

  17. The breakup of thin air films caught under impacting drops

    NASA Astrophysics Data System (ADS)

    Thoroddsen, Sigurdur; Thoraval, Marie-Jean; Takehara, Kohsei; Etoh, T. Goji

    2012-11-01

    When a drop impacts a pool at very low velocities V, an air layer cushions the impact and prevents immediate contact. This air layer is stretched into a hemispheric shape and thins to a submicron thickness. We use silicone oils, where these films are more stable than for water [Saylor & Bounds (2012), AIChE J., online: doi 10.1002/aic.13764 ]. We observe three main breakup mechanisms which are imprinted onto the micro-bubble morphology. First, for lowest V the film ruptures at isolated holes which grow rapidly, leaving bubble necklaces where their edges meet. Based on micro-bubble volumes, we show the film breaks by van der Waals, when its thickness ~ 100 nm. Secondly, for slightly larger V a ring of holes appearing a fixed depth, where the film is thinnest, producing bubble chandeliers. Finally, for larger V an air jet within the drop, ruptures it at the bottom tip, in an axisymmetric breakup. We measure the rupture speed and find that for very viscous liquids, the breakup moves faster than the capillary-viscous velocity, through the repeated ruptures. [Thoroddsen, Thoraval, Takehara & Etoh (2012), J. Fluid Mech. online: doi:10.1017/jfm.2012.319].

  18. Hydrogen film cooling of a small hydrogen-oxygen thrust chamber and its effect on erosion rates of various ablative materials

    NASA Technical Reports Server (NTRS)

    Hannum, N.; Roberts, W. E.; Russell, L. M.

    1977-01-01

    An experimental investigation was conducted to determine what arrangement of film-coolant-injection orifices should be used to decrease the erosion rates of small, high temperature, high pressure ablative thrust chambers without incurring a large penalty in combustion performance. All of the film cooling was supplied through holes in a ring between the outer row of injector elements and the chamber wall. The best arrangement, which had twice the number of holes as there were outer row injection elements, was also the simplest. The performance penalties, presented as a reduction in characteristic exhaust velocity efficiency, were 0.8 and 2.8 percentage points for the 10 and 20 percent cooling flows, respectively, The best film-coolant injector was then used to obtain erosion rates for 19 ablative materials. The throat erosion rate was reduced by a factor of 2.5 with a 10 percent coolant flow. Only the more expensive silica phenolic materials had low enough erosion rates to be considered for use in the nozzle throat. However, some of the cheaper materials might qualify for use in other areas of small nozzles with large throat diameters where the higher erosion rates are more acceptable.

  19. Thin-film silicon for flexible metal-air batteries.

    PubMed

    Garamoun, Ahmed; Schubert, Markus B; Werner, Jürgen H

    2014-12-01

    Due to its high energy density, theoretical studies propose silicon as a promising candidate material for metal-air batteries. Herein, for the first time, experimental results detail the use of n-type doped amorphous silicon and silicon carbide as fuel in Si-air batteries. Thin-film silicon is particularly interesting for flexible and rolled batteries with high specific energies. Our Si-air batteries exhibit a specific capacity of 269 Ah kg(-1) and an average cell voltage of 0.85 V at a discharge current density of 7.9 μA cm(-2) , corresponding to a specific energy of 229 Wh kg(-1) . Favorably in terms of safety, low concentrated alkaline solution serves as electrolyte. Discharging of the Si-air cells continues as long as there is silicon available for oxidation.

  20. Thin-film silicon for flexible metal-air batteries.

    PubMed

    Garamoun, Ahmed; Schubert, Markus B; Werner, Jürgen H

    2014-12-01

    Due to its high energy density, theoretical studies propose silicon as a promising candidate material for metal-air batteries. Herein, for the first time, experimental results detail the use of n-type doped amorphous silicon and silicon carbide as fuel in Si-air batteries. Thin-film silicon is particularly interesting for flexible and rolled batteries with high specific energies. Our Si-air batteries exhibit a specific capacity of 269 Ah kg(-1) and an average cell voltage of 0.85 V at a discharge current density of 7.9 μA cm(-2) , corresponding to a specific energy of 229 Wh kg(-1) . Favorably in terms of safety, low concentrated alkaline solution serves as electrolyte. Discharging of the Si-air cells continues as long as there is silicon available for oxidation. PMID:25251223

  1. Surface modification of PE film by DBD plasma in air

    NASA Astrophysics Data System (ADS)

    Ren, C.-S.; Wang, K.; Nie, Q.-Y.; Wang, D.-Z.; Guo, S.-H.

    2008-12-01

    In this paper, surface modification of polyethylene (PE) films is studied by dielectric barrier discharge plasma treatment in air. The treated samples were examined by water contact angle measurement, calculation of surface free energy, Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The water contact angle changes from the original value of 93.2° to the minimum value of 53.3° and surface free energy increases from 27.3 to 51.89 J/m 2 after treatment time of 50 s. Both ATR and XPS show some oxidized species are introduced into the sample surface by the plasma treatment and that the change tendencies of the water contact angle and surface free energy with the treatment time are the same as that of the oxygen concentration on the treated sample surface. Cu films were deposited on the treated and untreated PE surfaces. The peel adhesive strength between the Cu film and the treated sample is 1.5 MPa, whereas the value is only 0.8 MPa between the Cu film and the untreated PE. SEM pictures show that the Cu film deposited on the plasma treated PE surface is smooth and the crystal grain is smaller, contrarily the Cu film on the untreated PE surface is rough and the crystal grain is larger.

  2. Noise generated by a flight weight, air flow control valve in a vertical takeoff and landing aircraft thrust vectoring system

    NASA Technical Reports Server (NTRS)

    Huff, Ronald G.

    1989-01-01

    Tests were conducted in the NASA Lewis Research Center's Powered Lift Facility to experimentally evaluate the noise generated by a flight weight, 12 in. butterfly valve installed in a proposed vertical takeoff and landing thrust vectoring system. Fluctuating pressure measurements were made in the circular duct upstream and downstream of the valve. This data report presents the results of these tests. The maximum overall sound pressure level is generated in the duct downstream of the valve and reached a value of 180 dB at a valve pressure ratio of 2.8. At the higher valve pressure ratios the spectra downstream of the valve is broad banded with its maximum at 1000 Hz.

  3. Film cooling air pocket in a closed loop cooled airfoil

    DOEpatents

    Yu, Yufeng Phillip; Itzel, Gary Michael; Osgood, Sarah Jane; Bagepalli, Radhakrishna; Webbon, Waylon Willard; Burdgick, Steven Sebastian

    2002-01-01

    Turbine stator vane segments have radially inner and outer walls with vanes extending between them. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. To provide for air film cooing of select portions of the airfoil outer surface, at least one air pocket is defined on a wall of at least one of the cavities. Each air pocket is substantially closed with respect to the cooling medium in the cavity and cooling air pumped to the air pocket flows through outlet apertures in the wall of the airfoil to cool the same.

  4. Properties of amphiphilic oligonucleotide films at the air/water interface and after film transfer.

    PubMed

    Keller, R; Kwak, M; de Vries, J W; Sawaryn, C; Wang, J; Anaya, M; Müllen, K; Butt, H-J; Herrmann, A; Berger, R

    2013-11-01

    The self-assembly of amphiphilic hybrid materials containing an oligonucleotide sequence at the air/water interface was investigated by means of pressure-molecular area (Π-A) isotherms. In addition, films were transferred onto solid substrates and imaged using scanning force microscopy. We used oligonucleotide molecules with lipid tails, which consisted of a single stranded oligonucleotide 11 mer containing two hydrophobically modified 5-(dodec-1-ynyl)uracil nucleobases (dU11) at the 5'-end of the oligonucleotide sequence. The air/water interface was used as confinement for the self-assembling process of dU11. Scanning force microscopy of films transferred via Langmuir-Blodgett technique revealed mono-, bi- (Π ≥ 2 mN/m) and multilayer formation (Π ≥ 30 mN/m). The first layer was 1.6 ± 0.1 nm thick. It was oriented with the hydrophilic oligonucleotide moiety facing the hydrophilic substrate while the hydrophobic alkyl chains faced air. In the second layer the oligonucleotide moiety was found to face the air. The second layer was found to cover up to 95% of the sample area. Our measurements indicated that the rearrangement of the molecules into bi- and multiple bilayers happened already at the air/water interface. Similar results were obtained with a second type of oligonucleotide amphiphile, an oligonucleotide block copolymer, which was composed of an oligonucleotide 11 mer covalently attached at the terminus to polypropyleneoxide (PPO).

  5. Rupture of thin liquid films induced by impinging air-jets.

    PubMed

    Berendsen, Christian W J; Zeegers, Jos C H; Kruis, Geerit C F L; Riepen, Michel; Darhuber, Anton A

    2012-07-01

    Thin liquid films on partially wetting substrates are subjected to laminar axisymmetric air-jets impinging at normal incidence. We measured the time at which film rupture occurs and dewetting commences as a function of diameter and Reynolds number of the air-jet. We developed numerical models for the air flow as well as the height evolution of the thin liquid film. The experimental results were compared with numerical simulations based on the lubrication approximation and a phenomenological expression for the disjoining pressure. We achieved quantitative agreement for the rupture times. We found that the film thickness profiles were highly sensitive to the presence of minute quantities of surface-active contaminants.

  6. Thrust Characterization for Vortex Ring Thrusters

    NASA Astrophysics Data System (ADS)

    Krieg, Mike; Mohseni, Kamran

    2007-11-01

    Synthetic jets are zero net mass pulsatile jets that are commonly used in flow control applications in air. In these cases the natural resonant frequency of the actuators plays an important role. In this work we will present thrust characterization of vortex ring thrusters (VRTs) in liquid (equivalent of synthetic jets in liquid medium). VRTs design are motivated by pulsatile jet propulsion in squid and jellyfish. A prototype jet thruster was designed and build for this investigation. The effect of the actuation frequency and stroke ratio on the thrust level was experimentally studied. A simplified slug model was defined which predicted the thrust according to the momentum transfer. According to the model the thrust values for various frequencies converges to a single non-dimensionalized thrust, which is only a function of the stroke ratio. The accuracy of the model was defined in terms of a coefficient α which related predicted thrust values to those measured experimentally. This coefficient was observed to be nearly unity for stroke ratios below the formation number of the jet, and for frequencies below critical cavitation frequencies. α was seen to decrease (measured thrust drops below predicted thrust) with increasing frequency for all jets with stroke ratios above the formation number. The feasibility of using such a device in typical marine vehicles was tested by implementing the thruster in an unmanned underwater vehicle. The vehicle test-bed was operated in various dynamic maneuvers, including a simulated parallel park.

  7. Low-thrust chemical rocket engine study

    NASA Technical Reports Server (NTRS)

    Shoji, J. M.

    1981-01-01

    An analytical study evaluating thrust chamber cooling engine cycles and preliminary engine design for low thrust chemical rocket engines for orbit transfer vehicles is described. Oxygen/hydrogen, oxygen/methane, and oxygen/RP-1 engines with thrust levels from 444.8 N to 13345 N, and chamber pressures from 13.8 N/sq cm to 689.5 N/sq cm were evaluated. The physical and thermodynamic properties of the propellant theoretical performance data, and transport properties are documented. The thrust chamber cooling limits for regenerative/radiation and film/radiation cooling are defined and parametric heat transfer data presented. A conceptual evaluation of a number of engine cycles was performed and a 2224.1 N oxygen/hydrogen engine cycle configuration and a 2224.1 N oxygen/methane configuration chosen for preliminary engine design. Updated parametric engine data, engine design drawings, and an assessment of technology required are presented.

  8. Low Thrust Propulsion

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This video presents an overview of low thrust rocket engine propulsion concepts for space missions. Chemical and electrical rocket engines are shown. Animation illustrates various propulsion applications.

  9. Measuring axial pump thrust

    DOEpatents

    Suchoza, B.P.; Becse, I.

    1988-11-08

    An apparatus for measuring the hydraulic axial thrust of a pump under operation conditions is disclosed. The axial thrust is determined by forcing the rotating impeller off of an associated thrust bearing by use of an elongate rod extending coaxially with the pump shaft. The elongate rod contacts an impeller retainer bolt where a bearing is provided. Suitable measuring devices measure when the rod moves to force the impeller off of the associated thrust bearing and the axial force exerted on the rod at that time. The elongate rod is preferably provided in a housing with a heat dissipation mechanism whereby the hot fluid does not affect the measuring devices. 1 fig.

  10. Measuring axial pump thrust

    DOEpatents

    Suchoza, Bernard P.; Becse, Imre

    1988-01-01

    An apparatus for measuring the hydraulic axial thrust of a pump under operation conditions is disclosed. The axial thrust is determined by forcing the rotating impeller off of an associated thrust bearing by use of an elongate rod extending coaxially with the pump shaft. The elongate rod contacts an impeller retainer bolt where a bearing is provided. Suitable measuring devices measure when the rod moves to force the impeller off of the associated thrust bearing and the axial force exerted on the rod at that time. The elongate rod is preferably provided in a housing with a heat dissipation mechanism whereby the hot fluid does not affect the measuring devices.

  11. PPT Thrust Stand

    NASA Technical Reports Server (NTRS)

    Haag, Thomas W.

    1995-01-01

    A torsional-type thrust stand has been designed and built to test Pulsed Plasma Thrusters (PPT's) in both single shot and repetitive operating modes. Using this stand, momentum per pulse was determined strictly as a function of thrust stand deflection, spring constant, and natural frequency. No empirical corrections were required. The accuracy of the method was verified using a swinging impact pendulum. Momentum transfer data between the thrust stand and the pendulum were consistent to within 1%. Following initial calibrations, the stand was used to test a Lincoln Experimental Satellite (LES-8/9) thruster. The LES-8/9 system had a mass of approximately 7.5 kg, with a nominal thrust to weight ratio of 1.3 x 10(exp -5). A total of 34 single shot thruster pulses were individually measured. The average impulse bit per pulse was 266 microN-s, which was slightly less than the value of 300 microN-s published in previous reports on this device. Repetitive pulse measurements were performed similar to ordinary steady-state thrust measurements. The thruster was operated for 30 minutes at a repetition rate of 132 pulses per minute and yielded an average thrust of 573 microN. Using average thrust, the average impulse bit per pulse was estimated to be 260 microN-s, which was in agreement with the single shot data. Zero drift during the repetitive pulse test was found to be approximately 1% of the measured thrust.

  12. Variable thrust cartridge

    DOEpatents

    Taleyarkhan, Rusi P.

    2000-11-07

    The present invention is a variable thrust cartridge comprising a water-molten aluminum reaction chamber from which a slug is propelled. The cartridge comprises a firing system that initiates a controlled explosion from the reaction chamber. The explosive force provides a thrust to a slug, preferably contained within the cartridge.

  13. Ion thrusting system

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T. (Inventor)

    2007-01-01

    An ion thrusting system is disclosed comprising an ionization membrane having at least one area through which a gas is passed, and which ionizes the gas molecules passing therethrough to form ions and electrons, and an accelerator element which accelerates the ions to form thrust. In some variations, a potential is applied to the ionization membrane may be reversed to thrust ions in an opposite direction. The ionization membrane may also include an opening with electrodes that are located closer than a mean free path of the gas being ionized. Methods of manufacture and use are also provided.

  14. Thrust vectoring systems

    NASA Technical Reports Server (NTRS)

    King, H. J.; Schnelker, D.; Ward, J. W.; Dulgeroff, C.; Vahrenkamp, R.

    1972-01-01

    The design, fabrication, and testing of thrust vectorable ion optical systems capable of controlling the thrust direction from both 5- and 30-cm diameter ion thrusters is described. Both systems are capable of greater than 10 deg thrust deflection in any azimuthal direction. The 5-cm system is electrostatic and hence has a short response time and minimal power consumption. It has recently been tested for more than 7500 hours on an operational thruster. The 30-cm system is mechanical, has a response time of the order of 1 min, and consumes less than 0.3% of the total system input power at full deflection angle.

  15. Maximum thrust mode evaluation

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Nobbs, Steven G.

    1995-01-01

    Measured reductions in acceleration times which resulted from the application of the F-15 performance seeking control (PSC) maximum thrust mode during the dual-engine test phase is presented as a function of power setting and flight condition. Data were collected at altitudes of 30,000 and 45,000 feet at military and maximum afterburning power settings. The time savings for the supersonic acceleration is less than at subsonic Mach numbers because of the increased modeling and control complexity. In addition, the propulsion system was designed to be optimized at the mid supersonic Mach number range. Recall that even though the engine is at maximum afterburner, PSC does not trim the afterburner for the maximum thrust mode. Subsonically at military power, time to accelerate from Mach 0.6 to 0.95 was cut by between 6 and 8 percent with a single engine application of PSC, and over 14 percent when both engines were optimized. At maximum afterburner, the level of thrust increases were similar in magnitude to the military power results, but because of higher thrust levels at maximum afterburner and higher aircraft drag at supersonic Mach numbers the percentage thrust increase and time to accelerate was less than for the supersonic accelerations. Savings in time to accelerate supersonically at maximum afterburner ranged from 4 to 7 percent. In general, the maximum thrust mode has performed well, demonstrating significant thrust increases at military and maximum afterburner power. Increases of up to 15 percent at typical combat-type flight conditions were identified. Thrust increases of this magnitude could be useful in a combat situation.

  16. Pulsed laser deposition of air-sensitive hydride epitaxial thin films: LiH

    SciTech Connect

    Oguchi, Hiroyuki; Isobe, Shigehito; Kuwano, Hiroki; Shiraki, Susumu; Hitosugi, Taro; Orimo, Shin-ichi

    2015-09-01

    We report on the epitaxial thin film growth of an air-sensitive hydride, lithium hydride (LiH), using pulsed laser deposition (PLD). We first synthesized a dense LiH target, which is key for PLD growth of high-quality hydride films. Then, we obtained epitaxial thin films of [100]-oriented LiH on a MgO(100) substrate at 250 °C under a hydrogen pressure of 1.3 × 10{sup −2} Pa. Atomic force microscopy revealed that the film demonstrates a Stranski-Krastanov growth mode and that the film with a thickness of ∼10 nm has a good surface flatness, with root-mean-square roughness R{sub RMS} of ∼0.4 nm.

  17. Wettability-independent bouncing on flat surfaces mediated by thin air films

    NASA Astrophysics Data System (ADS)

    de Ruiter, Jolet; Lagraauw, Rudy; van den Ende, Dirk; Mugele, Frieder

    2015-01-01

    The impingement of drops onto solid surfaces plays a crucial role in a variety of processes, including inkjet printing, fog harvesting, anti-icing, dropwise condensation and spray coating. Recent efforts in understanding and controlling drop impact behaviour focused on superhydrophobic surfaces with specific surface structures enabling drop bouncing with reduced contact time. Here, we report a different universal bouncing mechanism that occurs on both wetting and non-wetting flat surfaces for both high and low surface tension liquids. Using high-speed multiple-wavelength interferometry, we show that this bouncing mechanism is based on the continuous presence of an air film for moderate drop impact velocities. This submicrometre `air cushion' slows down the incoming drop and reverses its momentum. Viscous forces in the air film play a key role in this process: they provide transient stability of the air cushion against squeeze-out, mediate momentum transfer, and contribute a substantial part of the energy dissipation during bouncing.

  18. A stably enhanced transparent conductive graphene film obtained using an air-annealing method

    NASA Astrophysics Data System (ADS)

    Song, Xuefen; Wei, Dapeng; Sun, Tai; Yu, Leyong; Yang, Jun; Zhang, Yongna; Fang, Liang; Wei, Dacheng; Shi, Haofei; Du, Chunlei

    2016-08-01

    A simple and effective air-annealing technique was developed to stably improve both the electrical conductivity and light transmission of pristine graphene. After the graphene film was annealed in air at 250 °C for 80 min, the mobility and carrier concentration were both significantly enhanced, and the sheet resistance was greatly reduced with a decrease rate of ∼33%. Meanwhile, the transparency was also improved by more than 3%. The mechanism is carefully discussed. The reason might be that air-annealing conditions provide a suitable atmosphere to etch and remove amorphous carbons. More importantly, the enhanced transparent conductive properties of the air-annealed graphene films were extraordinarily stable, and remained almost unchanged for 100 days.

  19. A stably enhanced transparent conductive graphene film obtained using an air-annealing method

    NASA Astrophysics Data System (ADS)

    Song, Xuefen; Wei, Dapeng; Sun, Tai; Yu, Leyong; Yang, Jun; Zhang, Yongna; Fang, Liang; Wei, Dacheng; Shi, Haofei; Du, Chunlei

    2016-08-01

    A simple and effective air-annealing technique was developed to stably improve both the electrical conductivity and light transmission of pristine graphene. After the graphene film was annealed in air at 250 °C for 80 min, the mobility and carrier concentration were both significantly enhanced, and the sheet resistance was greatly reduced with a decrease rate of ˜33%. Meanwhile, the transparency was also improved by more than 3%. The mechanism is carefully discussed. The reason might be that air-annealing conditions provide a suitable atmosphere to etch and remove amorphous carbons. More importantly, the enhanced transparent conductive properties of the air-annealed graphene films were extraordinarily stable, and remained almost unchanged for 100 days.

  20. Thrust Characteristics of Water Rocket and Their Improvement

    NASA Astrophysics Data System (ADS)

    Watanabe, Rikio; Tomita, Nobuyuki; Takemae, Toshiaki

    The propulsive characteristics of water rockets are analyzed theoretically and experimentally. The unsteady thrust force acting on a PET bottle and the air pressure inside the bottle are measured simultaneously by the thrust test stand we have developed. The semi-empirical thrust history is obtained utilizing the air pressure history and it is compared with the measured thrust history. The results show qualitative agreement. The observation of the flow inside bottle by a high-speed video camera shows that the air precedes water when it is about to be discharged entirely. We have developed a flow regulator attached to the nozzle cap to reduce the precursor air discharge that is considered as a result of the swirling flow inside the bottle. The experimental results show that the air discharge and the body vibration are suppressed effectively.

  1. Semiconducting organic thin films as monitoring devices for NO2 air pollution

    NASA Astrophysics Data System (ADS)

    Heilmann, A.; Lantto, V.

    The chemisorption of NO2 on lead phthalocyanine (PbPc) thin films changes the electrical conductivity of this semiconducting organic material and so the detection of NO2 concentration in the ppb range is possible. Some mesurements concerning the NO2 concentration in city air (Oulu, Finland) were carried out using this kind of device (PbPc thin film on metal slit electrodes). In the first part of the study, the sensor devices were heated in a test chamber up to 170 C and air from outside the laboratory was pumped into the test chamber using a conventional pump. In the second part of the study, a PbPc sensor with internal heating and measuring amplifier was installed directly at the city air pollution monitoring station where a commercial equipment based on chemiluminescnece was also used for continuous monitoring of the NO2 concentration in the city air. Good correlation between the sensor response and the chemiluminescence values was obtained under these circumstances. The measurements show that NO2 sensors based on PbPc thin films are suited to monitor NO2 as an air pollutant in city air.

  2. Thrust stand for low-thrust liquid pulsed rocket engines.

    PubMed

    Xing, Qin; Zhang, Jun; Qian, Min; Jia, Zhen-yuan; Sun, Bao-yuan

    2010-09-01

    A thrust stand is developed for measuring the pulsed thrust generated by low-thrust liquid pulsed rocket engines. It mainly consists of a thrust dynamometer, a base frame, a connecting frame, and a data acquisition and processing system. The thrust dynamometer assembled with shear mode piezoelectric quartz sensors is developed as the core component of the thrust stand. It adopts integral shell structure. The sensors are inserted into unique double-elastic-half-ring grooves with an interference fit. The thrust is transferred to the sensors by means of static friction forces of fitting surfaces. The sensors could produce an amount of charges which are proportional to the thrust to be measured. The thrust stand is calibrated both statically and dynamically. The in situ static calibration is performed using a standard force sensor. The dynamic calibration is carried out using pendulum-typed steel ball impact technique. Typical thrust pulse is simulated by a trapezoidal impulse force. The results show that the thrust stand has a sensitivity of 25.832 mV/N, a linearity error of 0.24% FSO, and a repeatability error of 0.23% FSO. The first natural frequency of the thrust stand is 1245 Hz. The thrust stand can accurately measure thrust waveform of each firing, which is used for fine control of on-orbit vehicles in the thrust range of 5-20 N with pulse frequency of 50 Hz. PMID:20887003

  3. Generation of Air Microplasma Jet and Its Application to Local Etching of Polyimide Films

    NASA Astrophysics Data System (ADS)

    Yoshiki, Hiroyuki

    2006-06-01

    An air microplasma jet (air μ-PJ) was generated at the tip of a stainless steel surgical needle with outer diameters of 0.4-0.7 mm at air flow rates of 0.3-1.0 l/min and RF (13.56 MHz) powers of 4-14 W, in which the air μ-PJ was operated without generating arc discharge at atmospheric pressure. The needle acts as both a powered electrode and a narrow gas nozzle. The peak-to-peak voltages Vpp were 1.5-1.7 kV and the temperatures of the plasma-irradiated spot (φ<1 mm) were 70-160 °C. The air μ-PJ was applied to the local etching of polyimide films with a thickness of 0.025 mm. A polyimide etch rate of approximately 5 μm/s was attained using a 0.4-mm-φ needle electrode at a RF power of 8 W. The etching mechanism was not based on a thermal effect but on a chemical reaction of oxygen atoms. Furthermore, the local removal of a polyamide-imide insulator film coated on a copper winding wire (φ<0.25 mm) was demonstrated and a good selectivity of the insulator film to a copper wire was achieved at a RF power of 7 W and plasma irradiation times of 5-20 s.

  4. Three-dimensionally ordered array of air bubbles in a polymer film

    NASA Technical Reports Server (NTRS)

    Srinivasarao, M.; Collings, D.; Philips, A.; Patel, S.; Brown, C. S. (Principal Investigator)

    2001-01-01

    We report the formation of a three-dimensionally ordered array of air bubbles of monodisperse pore size in a polymer film through a templating mechanism based on thermocapillary convection. Dilute solutions of a simple, coil-like polymer in a volatile solvent are cast on a glass slide in the presence of moist air flowing across the surface. Evaporative cooling and the generation of an ordered array of breath figures leads to the formation of multilayers of hexagonally packed water droplets that are preserved in the final, solid polymer film as spherical air bubbles. The dimensions of these bubbles can be controlled simply by changing the velocity of the airflow across the surface. When these three-dimensionally ordered macroporous materials have pore dimensions comparable to the wavelength of visible light, they are of interest as photonic band gaps and optical stop-bands.

  5. Photodegradation of the electronic structure of PCBM and C60 films in air

    NASA Astrophysics Data System (ADS)

    Anselmo, Ana S.; Dzwilewski, Andrzej; Svensson, Krister; Moons, Ellen

    2016-05-01

    Fullerenes are common electron acceptors in organic solar cells. Here the photostability in air of the electronic structures of spin-coated PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) and evaporated C60 films are studied using ultraviolet photoelectron spectroscopy (UPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. After exposing these materials in air to simulated sunlight, the filled and empty molecular orbitals are strongly altered, indicating that the conjugated π-system of the C60-cage has degraded. Even a few minutes in normal lab light induces changes. These results stress the importance of protecting fullerene-based films from light and air during processing, operation, and storage.

  6. Static Performance of Six Innovative Thrust Reverser Concepts for Subsonic Transport Applications: Summary of the NASA Langley Innovative Thrust Reverser Test Program

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Yetter, Jeffrey A.

    2000-01-01

    The NASA Langley Configuration Aerodynamics Branch has conducted an experimental investigation to study the static performance of innovative thrust reverser concepts applicable to high-bypass-ratio turbofan engines. Testing was conducted on a conventional separate-flow exhaust system configuration, a conventional cascade thrust reverser configuration, and six innovative thrust reverser configurations. The innovative thrust reverser configurations consisted of a cascade thrust reverser with porous fan-duct blocker, a blockerless thrust reverser, two core-mounted target thrust reversers, a multi-door crocodile thrust reverser, and a wing-mounted thrust reverser. Each of the innovative thrust reverser concepts offer potential weight savings and/or design simplifications over a conventional cascade thrust reverser design. Testing was conducted in the Jet-Exit Test Facility at NASA Langley Research Center using a 7.9%-scale exhaust system model with a fan-to-core bypass ratio of approximately 9.0. All tests were conducted with no external flow and cold, high-pressure air was used to simulate core and fan exhaust flows. Results show that the innovative thrust reverser concepts achieved thrust reverser performance levels which, when taking into account the potential for system simplification and reduced weight, may make them competitive with, or potentially more cost effective than current state-of-the-art thrust reverser systems. All data gathered in this investigation are contained in the CD-ROM.

  7. Static Performance of Six Innovative Thrust Reverser Concepts for Subsonic Transport Applications: Summary of the NASA Langley Innovative Thrust Reverser Test Program

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Yetter, Jeffrey A.

    2000-01-01

    The NASA Langley Configuration Aerodynamics Branch has conducted an experimental investigation to study the static performance of innovative thrust reverser concepts applicable to high-bypass-ratio turbofan engines. Testing was conducted on a conventional separate-flow exhaust system configuration, a conventional cascade thrust reverser configuration, and six innovative thrust reverser configurations. The innovative thrust reverser configurations consisted of a cascade thrust reverser with porous fan-duct blocker, a blockerless thrust reverser, two core-mounted target thrust reversers, a multi-door crocodile thrust reverser, and a wing-mounted thrust reverser. Each of the innovative thrust reverser concepts offer potential weight savings and/or design simplifications over a conventional cascade thrust reverser design. Testing was conducted in the Jet-Exit Test Facility at NASA Langley Research Center using a 7.9%-scale exhaust system model with a fan-to-core bypass ratio of approximately 9.0. All tests were conducted with no external flow and cold, high-pressure air was used to simulate core and fan exhaust flows. Results show that the innovative thrust reverser concepts achieved thrust reverser performance levels which, when taking into account the potential for system simplification and reduced weight, may make them competitive with, or potentially more cost effective than current state-of-the-art thrust reverser systems.

  8. 53. THRUST SECTION HEATER AND GASEOUS NITROGEN PURGE CONTROLS ON ...

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

    53. THRUST SECTION HEATER AND GASEOUS NITROGEN PURGE CONTROLS ON EAST SIDE OF LAUNCH DECK. LAUNCHER IN BACKGROUND. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  9. Low-thrust chemical rocket engine study

    NASA Technical Reports Server (NTRS)

    Mellish, J. A.

    1980-01-01

    Parametric data and preliminary designs on liquid rocket engines for low thrust cargo orbit-transfer-vehicles are described and those items where technology is required to enhance the designs are identified. The results of film cooling studies to establish the upper chamber pressure limit are given. The study showed that regen cooling with RP-1 was not feasible over the entire thrust and chamber pressure ranges. The thermal data showed that the RP-1 bulk temperature exceeded the study coking temperature limit of 1010 R. Based upon the results presented, O2/H2 and O2/CH4 regen engine systems and O2/H2 film cooled engines were selected for further study in the system analysis. Six engine design concepts are examined.

  10. Thin-film encapsulation of the air-sensitive organic-based ferrimagnet vanadium tetracyanoethylene

    SciTech Connect

    Froning, I. H.; Harberts, M.; Yu, H.; Johnston-Halperin, E.; Lu, Y.; Epstein, A. J.

    2015-03-23

    The organic-based ferrimagnet vanadium tetracyanoethylene (V[TCNE]{sub x∼2}) has demonstrated potential for use in both microwave electronics and spintronics due to the combination of high temperature magnetic ordering (T{sub C} > 600 K), extremely sharp ferromagnetic resonance (peak to peak linewidth of 1 G), and low-temperature conformal deposition via chemical vapor deposition (deposition temperature of 50 °C). However, air-sensitivity leads to the complete degradation of the films within 2 h under ambient conditions, with noticeable degradation occurring within 30 min. Here, we demonstrate encapsulation of V[TCNE]{sub x∼2} thin films using a UV-cured epoxy that increases film lifetime to over 710 h (30 days) as measured by the remanent magnetization. The saturation magnetization and Curie temperature decay more slowly than the remanence, and the coercivity is unchanged after 340 h (14 days) of air exposure. Fourier transform infrared spectroscopy indicates that the epoxy does not react with the film, and magnetometry measurements show that the presence of the epoxy does not degrade the magnetic properties. This encapsulation strategy directly enables a host of experimental protocols and investigations not previously feasible for air-sensitive samples and lays the foundation for the development of practical applications for this promising organic-based magnetic material.

  11. Formation, disruption and mechanical properties of a rigid hydrophobin film at an air-water interface

    NASA Astrophysics Data System (ADS)

    Walker, Lynn; Kirby, Stephanie; Anna, Shelley; CMU Team

    Hydrophobins are small, globular proteins with distinct hydrophilic and hydrophobic regions that make them extremely surface active. The behavior of hydrophobins at surfaces has raised interest in their potential industrial applications, including use in surface coatings, food foams and emulsions, and as dispersants. Practical use of hydrophobins requires an improved understanding of the interfacial behavior of these proteins, both individually and in the presence of surfactants. Cerato-ulmin (CU) is a hydrophobin that has been shown to strongly stabilize air bubbles and oil droplets through the formation of a persistent protein film at the interface. In this work, we characterize the adsorption behavior of CU at air/water interfaces by measuring the surface tension and interfacial rheology as a function of adsorption time. CU is found to strongly, irreversibly adsorb at air/water interfaces; the magnitude of the dilatational modulus increases with adsorption time and surface pressure, until the CU eventually forms a rigid film. The persistence of this film is tested through the addition of SDS, a strong surfactant, to the bulk. SDS is found to co-adsorb to interfaces pre-coated with a CU film. At high concentrations, the addition of SDS significantly decreases the dilatational modulus, indicating disruption and displacement of CU. These results lend insight into the complex interfacial interactions between hydrophobins and surfactants. Funding from GoMRI.

  12. Air-stable solution-processed n-channel organic thin film transistors with polymerenhanced morphology

    DOE PAGES

    He, Zhengran; Shaik, Shoieb; Bi, Sheng; Chen, Jihua; Li, Dawen

    2015-05-04

    N,N0-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN2) is an n-type semiconductor exhibiting high electron mobility and excellent air stability. However, the reported electron mobility based on spin-coated PDIF-CN2 film is much lower than the value of PDIF-CN2 single crystals made from vapor phase deposition, indicating significant room for mobility enhancement. In this study, various insulating polymers, including poly(vinyl alcohol), poly(methyl methacrylate) (PMMA), and poly(alpha-methylstyrene) (PaMS), are pre-coated on silicon substrate aiming to enhance the morphology of the PDIF-CN2 thin film, thereby improving the charge transport and air stability. Atomic force microscopy images reveal that with the pre-deposition of PaMS or PMMA polymers, the morphologymore » of the PDIF-CN2 polycrystalline films is optimized in semiconducting crystal connectivity, domain size, and surface roughness, which leads to significant improvement of organic thin-film transistor (OTFT) performance. Particularly, an electron mobility of up to 0.55 cm2/V s has been achieved from OTFTs based on the PDIF-CN2 film with the pre-deposition of PaMS polymer.« less

  13. Localized etching of polymer films using an atmospheric pressure air microplasma jet

    NASA Astrophysics Data System (ADS)

    Guo, Honglei; Liu, Jingquan; Yang, Bin; Chen, Xiang; Yang, Chunsheng

    2015-01-01

    A direct-write process device based on the atmospheric pressure air microplasma jet (AμPJ) has been developed for the localized etching of polymer films. The plasma was generated by the air discharge ejected out through a tip-nozzle (inner diameter of 100 μm), forming the microplasma jet. The AμPJ was capable of reacting with the polymer surface since it contains a high concentration of oxygen reactive species and thus resulted in the selective removal of polymer films. The experimental results demonstrated that the AμPJ could fabricate different microstructures on a parylene-C film without using any masks or causing any heat damage. The etch rate of parylene-C reached 5.1 μm min-1 and microstructures of different depth and width could also be realized by controlling two process parameters, namely, the etching time and the distance between the nozzle and the substrate. In addition, combining XPS analysis and oxygen-induced chemical etching principles, the potential etching mechanism of parylene-C by the AμPJ was investigated. Aside from the etching of parylene-C, micro-holes on the photoresist and polyimide film were successfully created by the AμPJ. In summary, maskless pattern etching of polymer films could be achieved using this AμPJ.

  14. Air-stable solution-processed n-channel organic thin film transistors with polymerenhanced morphology

    SciTech Connect

    He, Zhengran; Shaik, Shoieb; Bi, Sheng; Chen, Jihua; Li, Dawen

    2015-05-04

    N,N0-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN2) is an n-type semiconductor exhibiting high electron mobility and excellent air stability. However, the reported electron mobility based on spin-coated PDIF-CN2 film is much lower than the value of PDIF-CN2 single crystals made from vapor phase deposition, indicating significant room for mobility enhancement. In this study, various insulating polymers, including poly(vinyl alcohol), poly(methyl methacrylate) (PMMA), and poly(alpha-methylstyrene) (PaMS), are pre-coated on silicon substrate aiming to enhance the morphology of the PDIF-CN2 thin film, thereby improving the charge transport and air stability. Atomic force microscopy images reveal that with the pre-deposition of PaMS or PMMA polymers, the morphology of the PDIF-CN2 polycrystalline films is optimized in semiconducting crystal connectivity, domain size, and surface roughness, which leads to significant improvement of organic thin-film transistor (OTFT) performance. Particularly, an electron mobility of up to 0.55 cm2/V s has been achieved from OTFTs based on the PDIF-CN2 film with the pre-deposition of PaMS polymer.

  15. Thrust Augmentation with Mixer/Ejector Systems

    NASA Technical Reports Server (NTRS)

    Presz, Walter M., Jr.; Reynolds, Gary; Hunter, Craig

    2002-01-01

    Older commercial aircraft often exceed FAA (Federal Aviation Administration) sideline noise regulations. The major problem is the jet noise associated with the high exhaust velocities of the low bypass ratio engines on such aircraft. Mixer/ejector exhaust systems can provide a simple means of reducing the jet noise on these aircraft by mixing cool ambient air with the high velocity engine gases before they are exhausted to ambient. This paper presents new information on thrust performance predictions, and thrust augmentation capabilities of mixer/ejectors. Results are presented from the recent development program of the patented Alternating Lobe Mixer Ejector Concept (ALMEC) suppressor system for the Gulfstream GII, GIIB and GIII aircraft. Mixer/ejector performance procedures are presented which include classical control volume analyses, compound compressible flow theory, lobed nozzle loss correlations and state of the art computational fluid dynamic predictions. The mixer/ejector thrust predictions are compared to subscale wind tunnel test model data and actual aircraft flight test measurements. The results demonstrate that a properly designed mixer/ejector noise suppressor can increase effective engine bypass ratio and generate large thrust gains at takeoff conditions with little or no thrust loss at cruise conditions. The cruise performance obtained for such noise suppressor systems is shown to be a strong function of installation effects on the aircraft.

  16. Environmental Thrust Handbook.

    ERIC Educational Resources Information Center

    Department of Agriculture, Washington, DC.

    This handbook was prepared as a tool to assist U. S. Department of Agriculture (USDA) employees coordinate their resources and efforts to help people improve their environment. Twenty-two projects are outlined as potential environmental thrusts at the community level. It is the role of USDA employees to encourage and assist, in every way possible,…

  17. Experimentally determined stiffness and damping of an inherently compensated air squeeze-film damper

    NASA Technical Reports Server (NTRS)

    Cunningham, R. E.

    1975-01-01

    Values of damping and stiffness were determined experimentally for an externally pressurized, inherently compensated, compressible squeeze-film damper up to excitation frequencies of 36,000 cycles per minute. Experimental damping values were higher than theory predicted at low squeeze numbers and less than predicted at high squeeze numbers. Experimental values of air film stiffness were less than theory predicted at low squeeze numbers and much greater at higher squeeze numbers. Results also indicate sufficient damping to attenuate amplitudes and forces at the critical speed when using three dampers in the flexible support system of a small, lightweight turborotor.

  18. Surface shear rheology of WPI-monoglyceride mixed films spread at the air-water interface.

    PubMed

    Carrera Sánchez, Cecilio; Rodríguez Patino, Juan M

    2004-07-01

    Surface shear viscosity of food emulsifiers may contribute appreciably to the long-term stability of food dispersions (emulsions and foams). In this work we have analyzed the structural, topographical, and shear characteristics of a whey protein isolate (WPI) and monoglyceride (monopalmitin and monoolein) mixed films spread on the air-water interface at pH 7 and at 20 degrees C. The surface shear viscosity (etas) depend on the surface pressure and on the composition of the mixed film. The surface shear viscosity varies greatly with the surface pressure. In general, the greater the surface pressure, the greater are the values of etas. The values of etas for the mixed WPI-monoolein monolayer were more than one order of magnitude lower than those for a WPI-monopalmitin mixed film, especially at the higher surface pressures. At higher surface pressures, collapsed WPI residues may be displaced from the interface by monoglyceride molecules with important repercussions on the shear characteristics of the mixed films. A shear-induced change in the topography and a segregation between domains of the film forming components were also observed. The displacement of the WPI by the monoglycerides is facilitates under shear conditions, especially for WPI-monoolein mixed films.

  19. Permeability of acetic acid through organic films at the air-aqueous interface.

    PubMed

    Gilman, Jessica B; Vaida, Veronica

    2006-06-22

    Recent field studies of collected aerosol particles, both marine and continental, show that the outermost layers contain long-chain (C >or= 18) organics. The presence of these long-chain organics could impede the transport of gases and other volatile species across the interface. This could effect the particle's composition, lifetime, and heterogeneous chemistry. In this study, the uptake rate of acetic acid vapor across a clean interface and through films of long-chain organics into an aqueous subphase solution containing an acid-base indicator (bromocresol green) was measured under ambient conditions using visible absorption spectroscopy. Acetic acid is a volatile organic compound (VOC) and is an atmospherically relevant organic acid. The uptake of acetic acid through single-component organic films of 1-octadecanol (C(18)H(38)O), 1-triacontanol (C(30)H(62)O), cis-9-octadecen-1-ol (C(18)H(36)O), and nonacosane (C(29)H(60)) in addition to two mixed films containing equimolar 1-triacontanol/nonacosane and equimolar 1-triacontanol/cis-9-octadecen-1-ol was determined. These species represent long-chain organic compounds that reside at the air-aqueous interface of atmospheric aerosols. The cis-9-octadecen-1-ol film had little effect on the net uptake rate of acetic acid vapor into solution; however, the uptake rate was reduced by almost one-half by an interfacial film of 1-triacontanol. The measured uptake rates were used to calculate the permeability of acetic acid through the various films which ranged from 1.5 x 10(-3) cm s(-1) for 1-triacontanol, the least permeable film, to 2.5 x 10(-2) cm s(-1) for cis-9-octadecen-1-ol, the most permeable film. Both mixed films had permeabilities that were between that of the single-component films comprising the mixture. This shows that the permeability of a mixed film may not be solely determined by the most permeable species in the mixture. The permeabilities of all the films studied here are discussed in relation to their

  20. Dual-action gas thrust bearing for improving load capacity

    NASA Technical Reports Server (NTRS)

    Etsion, I.

    1976-01-01

    The principle of utilizing hydrodynamic effects in diverging films to improve the load carrying capacity in gas thrust bearings is discussed. A new concept of a dual action bearing based on that principle is described and analyzed. The potential of the new bearing is demonstrated both analytically for an infinitely long slider and by numerical solution for a flat sector shaped thrust bearing. It is shown that the dual action bearing can extend substantially the range of load carrying capacity in gas lubricated thrust bearings and can improve their efficiency.

  1. Kelvin–Helmholtz instability in an ultrathin air film causes drop splashing on smooth surfaces

    PubMed Central

    Liu, Yuan; Tan, Peng; Xu, Lei

    2015-01-01

    When a fast-moving drop impacts onto a smooth substrate, splashing will be produced at the edge of the expanding liquid sheet. This ubiquitous phenomenon lacks a fundamental understanding. Combining experiment with model, we illustrate that the ultrathin air film trapped under the expanding liquid front triggers splashing. Because this film is thinner than the mean free path of air molecules, the interior airflow transfers momentum with an unusually high velocity comparable to the speed of sound and generates a stress 10 times stronger than the airflow in common situations. Such a large stress initiates Kelvin–Helmholtz instabilities at small length scales and effectively produces splashing. Our model agrees quantitatively with experimental verifications and brings a fundamental understanding to the ubiquitous phenomenon of drop splashing on smooth surfaces. PMID:25713350

  2. Monte Mountain thrust, additional confirmation of the central Nevada thrust

    SciTech Connect

    Chamberlain, A.K. ); Chamberlain, R.L. )

    1990-05-01

    The Monte Mountain thrust, a newly identified thrust exposed in the Timpahute Range, east central Nevada places porous Devonian reservoir rocks over rich Mississippian source rocks at the peak oil generating window. The thrust provides insurmountable evidence of a thrust model that may lead to discovery of giant oil and gas fields along the 400-mi long central Nevada thrust belt. The Timpahute Range lies a little over 50 mi on strike to the south of the prolific Grant Canyon field. Scattered remnants of the north-trending thrust belt are obscured by parallel valleys of Tertiary valley fill and volcanics. The fact that the east-west-trending Timpahute Range could contain exposures of the north-south-trending central Nevada thrust belt attracted them to the range, Familiarity with the stratigraphic section led to the discovery of the thrust. As much as 750 ft of Devonian Guilmette sandstones, in the hanging wall just above the thrust contact have been erroneously mapped as Mississippian Scotty Wash sandstones. These Devonian sandstones could be excellent reservoir rocks. Sandstones in the Guilmette increase in thickness westward. East-vergent thrusting has juxtaposed plates of thicker Guilmette sandstones with plates of thinner sandstones, Reconstruction of Devonian paleogeography provides a clue to the amount of displacement along thrust boundaries.

  3. Air-Flow Navigated Crystal Growth for TIPS Pentacene-Based Organic Thin-Film Transistors

    SciTech Connect

    He, Zhengran; Chen, Jihua; Sun, Zhenzhong; Szulczewski, Greg; Li, Dawen

    2012-01-01

    6,13-bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) is a promising active channel material of organic thin-film transistors (OTFTs) due to its solubility, stability, and high mobility. However, the growth of TIPS pentacene crystals is intrinsically anisotropic and thus leads to significant variation in the performance of OTFTs. In this paper, air flow is utilized to effectively reduce the TIPS pentacene crystal anisotropy and enhance performance consistency in OTFTs, and the resulted films are examined with optical microscopy, grazing-incidence X-ray diffraction, and thin-film transistor measurements. Under air-flow navigation (AFN), TIPS pentacene drop-cast from toluene solution has been observed to form thin films with improved crystal orientation and increased areal coverage on substrates, which subsequently lead to a four-fold increase of average hole mobility and one order of magnitude enhancement in performance consistency defined by the ratio of average mobility to the standard deviation of the field-effect mobilities.

  4. Analytical modeling of squeeze air film damping of biomimetic MEMS directional microphone

    NASA Astrophysics Data System (ADS)

    Ishfaque, Asif; Kim, Byungki

    2016-08-01

    Squeeze air film damping is introduced in microelectromechanical systems due to the motion of the fluid between two closely spaced oscillating micro-structures. The literature is abundant with different analytical models to address the squeeze air film damping effects, however, there is a lack of work in modeling the practical sensors like directional microphones. Here, we derive an analytical model of squeeze air film damping of first two fundamental vibration modes, namely, rocking and bending modes, of a directional microphone inspired from the fly Ormia ochracea's ear anatomy. A modified Reynolds equation that includes compressibility and rarefaction effects is used in the analysis. Pressure distribution under the vibrating diaphragm is derived by using Green's function. From mathematical modeling of the fly's inspired mechanical model, we infer that bringing the damping ratios of both modes in the critical damping range enhance the directional sensitivity cues. The microphone parameters are varied in derived damping formulas to bring the damping ratios in the vicinity of critical damping, and to show the usefulness of the analytical model in tuning the damping ratios of both modes. The accuracy of analytical damping results are also verified by finite element method (FEM) using ANSYS. The FEM results are in full compliance with the analytical results.

  5. Static Thrust Analysis of the Lifting Airscrew

    NASA Technical Reports Server (NTRS)

    Knight, Montgomery; Hefner, Ralph A

    1937-01-01

    This report presents the results of a combined theoretical and experimental investigation conducted at the Georgia School of Technology on the static thrust of the lifting air screw of the type used in modern autogiros and helicopters. The theoretical part of this study is based on Glauert's analysis but certain modifications are made that further clarify and simplify the problem. Of these changes the elimination of the solidity as an independent parameter is the most important. The experimental data were obtained from tests on four rotor models of two, four, and five blades and, in general, agree quite well with the theoretical calculations. The theory indicates a method of evaluating scale effects on lifting air screws, and these corrections have been applied to the model results to derive general full-scale static thrust, torque, and figure-of-merit curves for constant-chord, constant-incidence rotors. Convenient charts are included that enable hovering flight performance to be calculated rapidly.

  6. Thin-Film Air-Mass-Flow Sensor of Improved Design Developed

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Wrbanek, John D.; Hwang, Danny P.

    2003-01-01

    Researchers at the NASA Glenn Research Center have developed a new air-mass-flow sensor to solve the problems of existing mass flow sensor designs. NASA's design consists of thin-film resistors in a Wheatstone bridge arrangement. The resistors are fabricated on a thin, constant-thickness airfoil to minimize disturbance to the airflow being measured. The following photograph shows one of NASA s prototype sensors. In comparison to other air-mass-flow sensor designs, NASA s thin-film sensor is much more robust than hot wires, causes less airflow disturbance than pitot tubes, is more accurate than vane anemometers, and is much simpler to operate than thermocouple rakes. NASA s thin-film air-mass-flow sensor works by converting the temperature difference seen at each leg of the thin-film Wheatstone bridge into a mass-flow rate. The following figure shows a schematic of this sensor with air flowing around it. The sensor operates as follows: current is applied to the bridge, which increases its temperature. If there is no flow, all the arms are heated equally, the bridge remains in balance, and there is no signal. If there is flow, the air passing over the upstream legs of the bridge reduces the temperature of the upstream legs and that leads to reduced electrical resistance for those legs. After the air has picked up heat from the upstream legs, it continues and passes over the downstream legs of the bridge. The heated air raises the temperature of these legs, increasing their electrical resistance. The resistance difference between the upstream and downstream legs unbalances the bridge, causing a voltage difference that can be amplified and calibrated to the airflow rate. Separate sensors mounted on the airfoil measure the temperature of the airflow, which is used to complete the calculation for the mass of air passing by the sensor. A current application for air-mass-flow sensors is as part of the intake system for an internal combustion engine. A mass-flow sensor is

  7. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate

    PubMed Central

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-01-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices. PMID:27507624

  8. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate

    NASA Astrophysics Data System (ADS)

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-08-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices.

  9. Spread Films of Human Serum Albumin at the Air-Water Interface: Optimization, Morphology, and Durability.

    PubMed

    Campbell, Richard A; Ang, Joo Chuan; Sebastiani, Federica; Tummino, Andrea; White, John W

    2015-12-22

    It has been known for almost one hundred years that a lower surface tension can be achieved at the air-water interface by spreading protein from a concentrated solution than by adsorption from an equivalent total bulk concentration. Nevertheless, the factors that control this nonequilibrium process have not been fully understood. In the present work, we apply ellipsometry, neutron reflectometry, X-ray reflectometry, and Brewster angle microscopy to elaborate the surface loading of human serum albumin in terms of both the macroscopic film morphology and the spreading dynamics. We show that the dominant contribution to the surface loading mechanism is the Marangoni spreading of protein from the bulk of the droplets rather than the direct transfer of their surface films. The films can be spread on a dilute subphase if the concentration of the spreading solution is sufficient; if not, dissolution of the protein occurs, and only a textured adsorbed layer slowly forms. The morphology of the spread protein films comprises an extended network with regions of less textured material or gaps. Further, mechanical cycling of the surface area of the spread films anneals the network into a membrane that approach constant compressibility and has increased durability. Our work provides a new perspective on an old problem in colloid and interface science. The scope for optimization of the surface loading mechanism in a range of systems leading to its exploitation in deposition-based technologies in the future is discussed.

  10. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate.

    PubMed

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-08-10

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices.

  11. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate.

    PubMed

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-01-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices. PMID:27507624

  12. Scalable Fabrication of Nanoporous Carbon Fiber Films as Bifunctional Catalytic Electrodes for Flexible Zn-Air Batteries.

    PubMed

    Liu, Qin; Wang, Yaobing; Dai, Liming; Yao, Jiannian

    2016-04-20

    A flexible nanoporous carbon-fiber film for wearable electronics is prepared by a facile and scalable method through pyrolysis of electrospun polyimide. It exhibits excellent bifunctional electrocatalytic activities for oxygen reduction and oxygen evolution. Flexible rechargeable zinc-air batteries based on the carbon-fiber film show high round-trip efficiency and mechanical stability.

  13. A Target Indirect Thrust Measurement Method of Pulse Detonation Engine

    NASA Astrophysics Data System (ADS)

    Huang, Xiqiao; Xiong, Yuefei; Li, Chao; Zheng, Longxi; Li, Qing

    2015-05-01

    An indirect thrust measurement method based on impulse of a target plate was developed, and a new thrust measurement system (TMS) was successfully designed and constructed. A series of multi-cycle experiments on thrust measurement were conducted to investigate the feasibility of this method with the newly-built indirect TMS. The thrust measurement of PDE was made at different plate target axial positions and operating frequencies. All the experiments were conducted using gasoline as fuel and air as oxidant. The experimental results implied that the thrust of PDE by using the indirect impulse method was a function of the target plate axial position, and there existed an optimum measurement position for PDE with a diameter of 60 mm. The optimum target plate position located at 3.33. According to the experimental results, the thrusts obtained by using indirect TMS were less than the actual values, and so the observed value of thrust was modified in order to make the thrust more reliable. A relative accurate calibration formula depending on the operating frequency was found.

  14. Thrust and propulsive efficiency from an instructive viewpoint

    NASA Astrophysics Data System (ADS)

    Kaufman, Richard D.

    2010-09-01

    In a typical engineering or physics curriculum, the momentum equation is used for the determination of jet engine thrust. Even a simple thrust analysis requires a heavy emphasis on mathematics that can cause students and engineers to lose a physical perspective on thrust. This article provides for this physical understanding using only static pressures that act on engine surfaces. Such an alternative, but equivalent, method can offer insights into some special examples of jet engine thrust that contradict commonly held beliefs. One such example is provided by the engine bellmouth that is used for testing jet engines on the ground. The static pressure distribution clearly shows that the engine bellmouth actually experiences forward thrust. Another example is provided by the conic exhaust nozzle that is used at the end of some jet engines. The static pressure distribution shows that the conic nozzle does not experience any forward thrust (although the nozzle increases the overall thrust of an engine through higher pressures upstream of the nozzle). Following these examples, a basis for conceptualizing propulsive efficiency is discussed. This illustrates that it is more efficient to have a smaller acceleration of a large amount of air than a larger acceleration of a smaller amount of air.

  15. Biodegradable polyester films from renewable aleuritic acid: surface modifications induced by melt-polycondensation in air

    NASA Astrophysics Data System (ADS)

    Jesús Benítez, José; Alejandro Heredia-Guerrero, José; Inmaculada de Vargas-Parody, María; Cruz-Carrillo, Miguel Antonio; Morales-Flórez, Victor; de la Rosa-Fox, Nicolás; Heredia, Antonio

    2016-05-01

    Good water barrier properties and biocompatibility of long-chain biopolyesters like cutin and suberin have inspired the design of synthetic mimetic materials. Most of these biopolymers are made from esterified mid-chain functionalized ω-long chain hydroxyacids. Aleuritic (9,10,16-trihydroxypalmitic) acid is such a polyhydroxylated fatty acid and is also the major constituent of natural lac resin, a relatively abundant and renewable resource. Insoluble and thermostable films have been prepared from aleuritic acid by melt-condensation polymerization in air without catalysts, an easy and attractive procedure for large scale production. Intended to be used as a protective coating, the barrier's performance is expected to be conditioned by physical and chemical modifications induced by oxygen on the air-exposed side. Hence, the chemical composition, texture, mechanical behavior, hydrophobicity, chemical resistance and biodegradation of the film surface have been studied by attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR), atomic force microscopy (AFM), nanoindentation and water contact angle (WCA). It has been demonstrated that the occurrence of side oxidation reactions conditions the surface physical and chemical properties of these polyhydroxyester films. Additionally, the addition of palmitic acid to reduce the presence of hydrophilic free hydroxyl groups was found to have a strong influence on these parameters.

  16. Biodegradable polyester films from renewable aleuritic acid: surface modifications induced by melt-polycondensation in air

    NASA Astrophysics Data System (ADS)

    Jesús Benítez, José; Alejandro Heredia-Guerrero, José; Inmaculada de Vargas-Parody, María; Cruz-Carrillo, Miguel Antonio; Morales-Flórez, Victor; de la Rosa-Fox, Nicolás; Heredia, Antonio

    2016-05-01

    Good water barrier properties and biocompatibility of long-chain biopolyesters like cutin and suberin have inspired the design of synthetic mimetic materials. Most of these biopolymers are made from esterified mid-chain functionalized ω-long chain hydroxyacids. Aleuritic (9,10,16-trihydroxypalmitic) acid is such a polyhydroxylated fatty acid and is also the major constituent of natural lac resin, a relatively abundant and renewable resource. Insoluble and thermostable films have been prepared from aleuritic acid by melt-condensation polymerization in air without catalysts, an easy and attractive procedure for large scale production. Intended to be used as a protective coating, the barrier's performance is expected to be conditioned by physical and chemical modifications induced by oxygen on the air-exposed side. Hence, the chemical composition, texture, mechanical behavior, hydrophobicity, chemical resistance and biodegradation of the film surface have been studied by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM), nanoindentation and water contact angle (WCA). It has been demonstrated that the occurrence of side oxidation reactions conditions the surface physical and chemical properties of these polyhydroxyester films. Additionally, the addition of palmitic acid to reduce the presence of hydrophilic free hydroxyl groups was found to have a strong influence on these parameters.

  17. Influence of annealing atmospheres and synthetic air treatment on solution processed zinc oxide thin film transistors

    NASA Astrophysics Data System (ADS)

    Busch, C.; Schierning, G.; Theissmann, R.; Schmechel, R.

    2012-08-01

    Thin film transistors (TFTs) based on active layers of zinc oxide prepared from a solution process were fabricated under different annealing conditions. The influence of the annealing gas as well as the influence of a subsequent exposure to synthetic air to the device properties is considered. Annealing under N2 or H2 atmosphere leads to a strong negative threshold voltage shift. With respect to known defect states in ZnO, two different donor states are suggested to be responsible for the negative threshold voltage. A subsequent synthetic air treatment causes in general a positive threshold voltage shift. However, transistors annealed under H2 degrade very fast under synthetic air in contrast to transistors annealed under N2. In order to obtain more information about the density of states (DOS) distribution, a transistor model for thin film transistors in the hopping transport regime (Vissenberg model) was utilized. For positive threshold voltages, the DOS distribution is independent from the gas treatment and the threshold voltage within the experimental accuracy. This indicates a shift of the Fermi-level within an exponentially decaying DOS. The change in the charge carrier density is either due to shallow donors or due to a charge transfer with acceptors at the surface. In contrast, for negative threshold voltages, the DOS distribution parameter rises, indicating a flatter DOS distribution. We suggest that the difference is due to the change from accumulation mode to the depletion mode of the device.

  18. 10. DETAIL SHOWING THRUST MEASURING SYSTEM. Looking up from the ...

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

    10. DETAIL SHOWING THRUST MEASURING SYSTEM. Looking up from the test stand deck to east. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  19. Recommended Practices in Thrust Measurements

    NASA Technical Reports Server (NTRS)

    Polk, James E.; Pancotti, Anthony; Haag, Thomas; King, Scott; Walker, Mitchell; Blakely, Joseph; Ziemer, John

    2013-01-01

    Accurate, direct measurement of thrust or impulse is one of the most critical elements of electric thruster characterization, and one of the most difficult measurements to make. The American Institute of Aeronautics and Astronautics has started an initiative to develop standards for many important measurement processes in electric propulsion, including thrust measurements. This paper summarizes recommended practices for the design, calibration, and operation of pendulum thrust stands, which are widely recognized as the best approach for measuring micro N- to mN-level thrust and micro Ns-level impulse bits. The fundamentals of pendulum thrust stand operation are reviewed, along with its implementation in hanging pendulum, inverted pendulum, and torsional balance configurations. Methods of calibration and recommendations for calibration processes are presented. Sources of error are identified and methods for data processing and uncertainty analysis are discussed. This review is intended to be the first step toward a recommended practices document to help the community produce high quality thrust measurements.

  20. Low thrust vehicle concept study

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Low thrust chemical (hydrogen-oxygen) propulsion systems configured specifically for low acceleration orbit transfer of large space systems were defined. Results indicate that it is cost effective and least risk to combine the OTV and stowed spacecraft in a single 65 K Shuttle. The study shows that the engine for an optimized low thrust stage (1) does not require very low thrust; (2) 1-3 K thrust range appears optimum; (3) thrust transient is not a concern; (4) throttling probably not worthwhile; and (5) multiple thrusters complicate OTV/LSS design and aggravate LSS loads. Regarding the optimum vehicle for low acceleration missions, the single shuttle launch (LSS and expendable OTV) is most cost effective and least risky. Multiple shuttles increase diameter 20%. The space based radar structure short OTV (which maximizes space available for packaged LSS) favors use of torus tank. Propellant tank pressures/vapor residuals are little affected by engine thrust level or number of burns.

  1. Lamellar Bodies Form Solid Three-dimensional Films at the Respiratory Air-Liquid Interface*

    PubMed Central

    Ravasio, Andrea; Olmeda, Bárbara; Bertocchi, Cristina; Haller, Thomas; Pérez-Gil, Jesús

    2010-01-01

    Pulmonary surfactant is essential for lung function. It is assembled, stored and secreted as particulate entities (lamellar body-like particles; LBPs). LBPs disintegrate when they contact an air-liquid interface, leading to an instantaneous spreading of material and a decline in surface tension. Here, we demonstrate that the film formed by the adsorbed material spontaneously segregate into distinct ordered and disordered lipid phase regions under unprecedented near-physiological conditions and, unlike natural surfactant purified from bronchoalveolar lavages, dynamically reorganized into highly viscous multilayer domains with complex three-dimensional topographies. Multilayer domains, in coexistence with liquid phases, showed a progressive stiffening and finally solidification, probably driven by a self-driven disassembly of LBPs from a sub-surface compartment. We conclude that surface film formation from LBPs is a highly dynamic and complex process, leading to a more elaborated scenario than that observed and predicted by models using reconstituted, lavaged, or fractionated preparations. PMID:20558742

  2. A 10 nN resolution thrust-stand for micro-propulsion devices

    SciTech Connect

    Chakraborty, Subha; Courtney, Daniel G.; Shea, Herbert

    2015-11-15

    We report on the development of a nano-Newton thrust-stand that can measure up to 100 μN thrust from different types of microthrusters with 10 nN resolution. The compact thrust-stand measures the impingement force of the particles emitted from a microthruster onto a suspended plate of size 45 mm × 45 mm and with a natural frequency over 50 Hz. Using a homodyne (lock-in) readout provides strong immunity to facility vibrations, which historically has been a major challenge for nano-Newton thrust-stands. A cold-gas thruster generating up to 50 μN thrust in air was first used to validate the thrust-stand. Better than 10 nN resolution and a minimum detectable thrust of 10 nN were achieved. Thrust from a miniature electrospray propulsion system generating up to 3 μN of thrust was measured with our thrust-stand in vacuum, and the thrust was compared with that computed from beam diagnostics, obtaining agreement within 50 nN to 150 nN. The 10 nN resolution obtained from this thrust-stand matches that from state-of-the-art nano-Newton thrust-stands, which measure thrust directly from the thruster by mounting it on a moving arm (but whose natural frequency is well below 1 Hz). The thrust-stand is the first of its kind to demonstrate less than 3 μN resolution by measuring the impingement force, making it capable of measuring thrust from different types of microthrusters, with the potential of easy upscaling for thrust measurement at much higher levels, simply by replacing the force sensor with other force sensors.

  3. Thrust measurement in a 2-D scramjet nozzle

    NASA Technical Reports Server (NTRS)

    Tuttle, Sean

    1995-01-01

    The two-dimensional thrust nozzle presents a challenging problem. The loading is not axisymmetric as in the case of a cone and the internal flow presents some design difficulties. A two-sting system has been chosen to accomodate the internal flow and achieve some symmetry. The situation is complicated by the fact that with the small ramp angle and the internal pressure on the nozzle walls, loading is predominantly transverse. Yet it is the axial thrust which is to be measured (i.e., the tensile waves propagating in the stings). Although bending stress waves travel at most at only 60% of the speed of the axial stress waves, the system needs to be stiffened against bending. The second sting was originally only used to preserve symmetry. However, the pressures on each thrust surface may be quite different at some conditions, so at this stage the signals from both stings are being averaged as a first order approximation of the net thrust. The expected axial thrust from this nozzle is not large so thin stings are required. In addition, the contact area between nozzle and sting needs to be maximized. The result was that it was decided to twist the stings through 90 deg, without distorting their cross-sectional shape, just aft of the nozzle. Finite element analysis showed that this would not significantly alter the propagation of the axial stress wave in the sting, while the rigidity of the system is greatly increased. A Mach 4 contoured nozzle is used in the experiments. The thrust calculated by integrating the static pressure measurements on the thrust surfaces is compared with the deconvolved strain measurement of the net thrust for the cases of air only and hydrogen fuel injected into air at approximately 9 MJ/kg nozzle supply enthalpy. The gain in thrust due to combustion is visible in this result.

  4. Influence of film thickness and air exposure on the transport gap of manganese phthalocyanine

    SciTech Connect

    Haidu, F.; Fechner, A.; Salvan, G.; Gordan, O. D.; Fronk, M.; Zahn, D. R. T.; Lehmann, D.; Mahns, B.; Knupfer, M.

    2013-06-15

    The interface formation between manganese phthalocyanine (MnPc) and cobalt was investigated combining ultraviolet photoelectron spectroscopy and inverse photoelectron spectroscopy. The transport band gap of the MnPc increases with the film thickness up to a value of (1.2 {+-} 0.3) eV while the optical band gap as determined from spectroscopic ellipsometry amounts to 0.5 eV. The gap values are smaller compared to other phthalocyanines due to metallic Mn 3d states close to the Fermi level. The transport band gap was found to open upon air exposure as a result of the disappearance of the occupied 3d electronic states.

  5. Screening of Novel Li-Air Battery Catalyst Materials by a Thin Film Combinatorial Materials Approach.

    PubMed

    Hauck, John G; McGinn, Paul J

    2015-06-01

    A combinatorial synthesis and high-throughput screening process was developed for the investigation of potential oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts for use as Li-air battery cathode materials. Libraries of discrete ternary metal alloy compositions were deposited via thin-film sputtering. The samples were electrochemically tested in parallel using cyclic voltammetry in O2-saturated KOH electrolyte. Compositions were ranked by ORR and OER onset potentials with respect to an internal Pt reference. Results from the Pt-Mn-Co, Cr-Mn-Co, Pd-Mn-Co, and Pd-Mn-Ru systems are reported. Many alloy compositions showed marked improvement in catalytic activity compared to pure Pt. Among the systems considered, Pt12Mn44Co44, Pd43Co57 and Pd36Mn28Ru36 in particular exhibited lower overpotentials for oxygen reactions, which occur at the cathode in Li-air batteries.

  6. Low-thrust chemical rocket engine study

    NASA Technical Reports Server (NTRS)

    Mellish, J. A.

    1981-01-01

    Engine data and information are presented to perform system studies on cargo orbit-transfer vehicles which would deliver large space structures to geosynchronous equatorial orbit. Low-thrust engine performance, weight, and envelope parametric data were established, preliminary design information was generated, and technologies for liquid rocket engines were identified. Two major engine design drivers were considered in the study: cooling and engine cycle options. Both film-cooled and regeneratively cooled engines were evaluated. The propellant combinations studied were hydrogen/oxygen, methane/oxygen, and kerosene/oxygen.

  7. Low thrust chemical rocket technology

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.

    1992-01-01

    An on-going technology program to improve the performance of low thrust chemical rockets for spacecraft on-board propulsion applications is reviewed. Improved performance and lifetime is sought by the development of new predictive tools to understand the combustion and flow physics, introduction of high temperature materials and improved component designs to optimize performance, and use of higher performance propellants. Improved predictive technology is sought through the comparison of both local and global predictions with experimental data. Predictions are based on both the RPLUS Navier-Stokes code with finite rate kinetics and the JANNAF methodology. Data were obtained with laser-based diagnostics along with global performance measurements. Results indicate that the modeling of the injector and the combustion process needs improvement in these codes and flow visualization with a technique such as 2-D laser induced fluorescence (LIF) would aid in resolving issues of flow symmetry and shear layer combustion processes. High temperature material fabrication processes are under development and small rockets are being designed, fabricated, and tested using these new materials. Rhenium coated with iridium for oxidation protection was produced by the Chemical Vapor Deposition (CVD) process and enabled an 800 K increase in rocket operating temperature. Performance gains with this material in rockets using Earth storable propellants (nitrogen tetroxide and monomethylhydrazine or hydrazine) were obtained through component redesign to eliminate fuel film cooling and its associated combustion inefficiency while managing head end thermal soakback. Material interdiffusion and oxidation characteristics indicated that the requisite lifetimes of tens of hours were available for thruster applications. Rockets were designed, fabricated, and tested with thrusts of 22, 62, 440 and 550 N. Performance improvements of 10 to 20 seconds specific impulse were demonstrated. Higher

  8. 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 ...

  9. Static Performance of a Wing-Mounted Thrust Reverser Concept

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Yetter, Jeffrey A.

    1998-01-01

    An experimental investigation was conducted in the Jet-Exit Test Facility at NASA Langley Research Center to study the static aerodynamic performance of a wing-mounted thrust reverser concept applicable to subsonic transport aircraft. This innovative engine powered thrust reverser system is designed to utilize wing-mounted flow deflectors to produce aircraft deceleration forces. Testing was conducted using a 7.9%-scale exhaust system model with a fan-to-core bypass ratio of approximately 9.0, a supercritical left-hand wing section attached via a pylon, and wing-mounted flow deflectors attached to the wing section. Geometric variations of key design parameters investigated for the wing-mounted thrust reverser concept included flow deflector angle and chord length, deflector edge fences, and the yaw mount angle of the deflector system (normal to the engine centerline or parallel to the wing trailing edge). All tests were conducted with no external flow and high pressure air was used to simulate core and fan engine exhaust flows. Test results indicate that the wing-mounted thrust reverser concept can achieve overall thrust reverser effectiveness levels competitive with (parallel mount), or better than (normal mount) a conventional cascade thrust reverser system. By removing the thrust reverser system from the nacelle, the wing-mounted concept offers the nacelle designer more options for improving nacelle aero dynamics and propulsion-airframe integration, simplifying nacelle structural designs, reducing nacelle weight, and improving engine maintenance access.

  10. Low-thrust rocket trajectories

    SciTech Connect

    Keaton, P.W.

    1986-01-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report. 57 refs., 10 figs.

  11. Low-thrust rocket trajectories

    SciTech Connect

    Keaton, P.W.

    1987-03-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report.

  12. Micro thrust and heat generator

    DOEpatents

    Garcia, Ernest J.

    1998-01-01

    A micro thrust and heat generator has a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator's ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachining techniques (LIGA).

  13. Micro thrust and heat generator

    DOEpatents

    Garcia, E.J.

    1998-11-17

    A micro thrust and heat generator have a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator`s ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachining techniques (LIGA). 30 figs.

  14. Direct thrust force measurement of pulse detonation engine

    NASA Astrophysics Data System (ADS)

    Wahid, Mazlan Abdul; Faiz, M. Z. Ahmad; Saqr, Khalid M.

    2012-06-01

    In this paper we present the result of High-Speed Reacting Flow Laboratory (HiREF) pulse detonation engine (PDE) experimental study on direct thrust measurement. The thrust force generated by the repetitive detonation from a 50 mm inner diameter and 600 mm length tube was directly measured using load cell. Shchelkin spiral was used as an accelerator for the Deflagration to Detonation Transition (DDT) phenomenon. Propane-oxygen at stoichiometric condition was used as the combustible fuel-air mixture for the PDE. The PDE was operated at the operation frequency of 3Hz during the test. The amount of thrust force that was measured during the test reaching up to 70N. These values of thrust force were found to be fluctuating and its combustion phenomenon has been analyzed and discussed.

  15. Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath

    NASA Astrophysics Data System (ADS)

    Williams, Jonathan; Stönner, Christof; Wicker, Jörg; Krauter, Nicolas; Derstroff, Bettina; Bourtsoukidis, Efstratios; Klüpfel, Thomas; Kramer, Stefan

    2016-05-01

    Human beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely “suspense” or “comedy” caused audiences to change their emission of specific chemicals. These event-type synchronous, broadcasted human chemosignals open the possibility for objective and non-invasive assessment of a human group response to stimuli by continuous measurement of chemicals in air. Such methods can be applied to research fields such as psychology and biology, and be valuable to industries such as film making and advertising.

  16. Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath.

    PubMed

    Williams, Jonathan; Stönner, Christof; Wicker, Jörg; Krauter, Nicolas; Derstroff, Bettina; Bourtsoukidis, Efstratios; Klüpfel, Thomas; Kramer, Stefan

    2016-01-01

    Human beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely "suspense" or "comedy" caused audiences to change their emission of specific chemicals. These event-type synchronous, broadcasted human chemosignals open the possibility for objective and non-invasive assessment of a human group response to stimuli by continuous measurement of chemicals in air. Such methods can be applied to research fields such as psychology and biology, and be valuable to industries such as film making and advertising. PMID:27160439

  17. Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath

    PubMed Central

    Williams, Jonathan; Stönner, Christof; Wicker, Jörg; Krauter, Nicolas; Derstroff, Bettina; Bourtsoukidis, Efstratios; Klüpfel, Thomas; Kramer, Stefan

    2016-01-01

    Human beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely “suspense” or “comedy” caused audiences to change their emission of specific chemicals. These event-type synchronous, broadcasted human chemosignals open the possibility for objective and non-invasive assessment of a human group response to stimuli by continuous measurement of chemicals in air. Such methods can be applied to research fields such as psychology and biology, and be valuable to industries such as film making and advertising. PMID:27160439

  18. Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath.

    PubMed

    Williams, Jonathan; Stönner, Christof; Wicker, Jörg; Krauter, Nicolas; Derstroff, Bettina; Bourtsoukidis, Efstratios; Klüpfel, Thomas; Kramer, Stefan

    2016-05-10

    Human beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely "suspense" or "comedy" caused audiences to change their emission of specific chemicals. These event-type synchronous, broadcasted human chemosignals open the possibility for objective and non-invasive assessment of a human group response to stimuli by continuous measurement of chemicals in air. Such methods can be applied to research fields such as psychology and biology, and be valuable to industries such as film making and advertising.

  19. Air cushioning in droplet impact. I. Dynamics of thin films studied by dual wavelength reflection interference microscopy

    NASA Astrophysics Data System (ADS)

    de Ruiter, Jolet; Mugele, Frieder; van den Ende, Dirk

    2015-01-01

    When a liquid droplet impacts on a solid surface, it not only deforms substantially but also an air film develops between the droplet and the surface. This thin air film—as well as other transparent films—can be characterized by reflection interference microscopy. Even for weakly reflecting interfaces, relative thickness variations of the order of tens of nanometers are easily detected, yet the absolute thickness is generally known only up to an additive constant which is a multiple of half of the wavelength. Here, we present an optical setup for measuring the absolute film thickness and its spatial and temporal behavior using a combination of a standard Hg lamp, an optical microscope, and three synchronized high-speed cameras to detect conventional side-view images as well as interferometric bottom view images at two different wavelengths. The combination of a dual wavelength approach with the finite coherence length set by the broad bandwidth of the optical filters allows for measuring the absolute thickness of transient air films with a spatial resolution better than 30 nm at 50 μs time resolution with a maximum detectable film thickness of approximately 8 μm. This technique will be exploited in Part II to characterize the air film evolution during low velocity droplet impacts.

  20. Effect of air annealing on structure and magnetic properties of Sn1-xFexO2 thin films

    NASA Astrophysics Data System (ADS)

    Kuppan, M.; Begam, M. Regana; Babu, S. Harinath; Kaleemulla, S.; Rao, N. Madhusudhana; Krishnamoorthi, C.

    2016-05-01

    Sn1-xFexO2 (x = 0.07) thin films were prepared on to glass substrates using flash evaporation technique and annealed in air at different temperatures. The X-ray diffraction study showsed that all the thin films annealed at different temperatures were in tetragonal rutile structure of SnO2. The Elemental analysis confirms the presence of Fe and Sn and O in the films. The magnetic measurements were carried out using vibrating sample magnetometer and found that the strength of magnetization decreased with increase of annealing temperature.

  1. Improved Rhenium Thrust Chambers

    NASA Technical Reports Server (NTRS)

    O'Dell, John Scott

    2015-01-01

    Radiation-cooled bipropellant thrust chambers are being considered for ascent/ descent engines and reaction control systems on various NASA missions and spacecraft, such as the Mars Sample Return and Orion Multi-Purpose Crew Vehicle (MPCV). Currently, iridium (Ir)-lined rhenium (Re) combustion chambers are the state of the art for in-space engines. NASA's Advanced Materials Bipropellant Rocket (AMBR) engine, a 150-lbf Ir-Re chamber produced by Plasma Processes and Aerojet Rocketdyne, recently set a hydrazine specific impulse record of 333.5 seconds. To withstand the high loads during terrestrial launch, Re chambers with improved mechanical properties are needed. Recent electrochemical forming (EL-Form"TM") results have shown considerable promise for improving Re's mechanical properties by producing a multilayered deposit composed of a tailored microstructure (i.e., Engineered Re). The Engineered Re processing techniques were optimized, and detailed characterization and mechanical properties tests were performed. The most promising techniques were selected and used to produce an Engineered Re AMBR-sized combustion chamber for testing at Aerojet Rocketdyne.

  2. Operating characteristics of a cantilever-mounted resilient-pad gas-lubricated thrust bearing

    NASA Technical Reports Server (NTRS)

    Nemeth, Z. N.

    1979-01-01

    A resilient-pad gas thrust bearing consisting of pads mounted on cantilever beams was tested to determine its operating characteristic. The bearing was run at a thrust load of 74 newtons to a speed of 17000 rpm. The pad film thickness and bearing friction torque were measured and compared with theory. The measured film thickness was less than that predicted by theory. The bearing friction torque was greater than that predicted by theory.

  3. LEO-to-GEO low thrust chemical propulsion

    NASA Technical Reports Server (NTRS)

    Shoji, J. M.

    1980-01-01

    One approach being considered for transporting large space structures from low Earth orbit (LEO) to geosynchronous equatorial orbit (GEO) is the use of low thrust chemical propulsion systems. A variety of chemical rocket engine cycles evaluated for this application for oxygen/hydrogen and oxygen/hydrocarbon propellants (oxygen/methane and oxygen/RF-1) are discussed. These cycles include conventional propellant turbine drives, turboalternator/electric motor pump drive, and fuel cell/electric motor pump drive as well as pressure fed engines. Thrust chamber cooling analysis results are presented for regenerative/radiation and film/radiation cooling.

  4. Comparison of effectiveness of convection-, transpiration-, and film-cooling methods with air as coolant

    NASA Technical Reports Server (NTRS)

    Eckert, E R G; Livingood, N B

    1954-01-01

    Various parts of aircraft propulsion engines that are in contact with hot gases often require cooling. Transpiration and film cooling, new methods that supposedly utilize cooling air more effectively than conventional convection cooling, have already been proposed. This report presents material necessary for a comparison of the cooling requirements of these three methods. Correlations that are regarded by the authors as the most reliable today are employed in evaluating each of the cooling processes. Calculations for the special case in which the gas velocity is constant along the cooled wall (flat plate) are presented. The calculations reveal that a comparison of the three cooling processes can be made on quite a general basis. The superiority of transpiration cooling is clearly shown for both laminar and turbulent flow. This superiority is reduced when the effects of radiation are included; for gas-turbine blades, however, there is evidence indicating that radiation may be neglected.

  5. Low thrust optimal orbital transfers

    NASA Technical Reports Server (NTRS)

    Cobb, Shannon S.

    1994-01-01

    For many optimal transfer problems it is reasonable to expect that the minimum time solution is also the minimum fuel solution. However, if one allows the propulsion system to be turned off and back on, it is clear that these two solutions may differ. In general, high thrust transfers resemble the well known impulsive transfers where the burn arcs are of very short duration. The low and medium thrust transfers differ in that their thrust acceleration levels yield longer burn arcs and thus will require more revolutions. In this research, we considered two approaches for solving this problem: a powered flight guidance algorithm previously developed for higher thrust transfers was modified and an 'averaging technique' was investigated.

  6. In-flight thrust determination

    NASA Technical Reports Server (NTRS)

    Abernethy, Robert B.; Adams, Gary R.; Ascough, John C.; Baer-Riedhart, Jennifer L.; Balkcom, George H.; Biesiadny, Thomas

    1986-01-01

    The major aspects of processes that may be used for the determination of in-flight thrust are reviewed. Basic definitions are presented as well as analytical and ground-test methods for gathering data and calculating the thrust of the propulsion system during the flight development program of the aircraft. Test analysis examples include a single-exhaust turbofan, an intermediate-cowl turbofan, and a mixed-flow afterburning turbofan.

  7. Effect of air annealing on structural, optical, morphological and electrical properties of thermally evaporated CdSe thin films

    NASA Astrophysics Data System (ADS)

    Purohit, A.; Chander, S.; Nehra, S. P.; Dhaka, M. S.

    2015-05-01

    In this paper, a study on effect of air annealing on structural, optical, morphological and electrical properties of CdSe thin films is undertaken. The thin films of thickness 810 nm were deposited on glass and ITO coated glass substrates employing thermal evaporation technique. The glass substrates were used to find structural, optical and morphological properties while ITO coated glass substrates for electrical properties. The as-deposited films were subjected to thermal annealing in air atmosphere at different temperatures 100 °C, 200 °C and 300 °C. The X-ray diffraction pattern shows that the films have cubic phase with preferred orientation (111). The structural parameters like inter-planner spacing, lattice constant, grain size, dislocation density, strain and number of crystallites per unit area are calculated. The grain size is found in the range 27.11-34.03 nm and observed to be varied with air annealing. The dislocation density and strain vary with annealing in the range (0.86-1.36)×1011 cm-2 and 0.276-0.347 respectively. The extinction coefficient is found to be increased at lower annealing temperature and decreased at higher. The refractive index is also calculated and found in the range 2.75-2.80. The AFM studies show that roughness of thin films are increased with annealing. The electrical resistivity is found to be decreased with annealing temperature. The results are in good agreement with the standard data and available literature.

  8. Micro thrust and heat generator

    SciTech Connect

    Garcia, E.J.

    1995-12-31

    The present invention relates generally to micromachines such as microengines or micromotors. More specifically, the invention is directed to a micro rocket which functions as a source of heat and thrust, and utilizes chemical energy to drive or power micromechanical apparatuses. The invention is adaptable to applications involving defense, bio-medical, manufacturing, consumer product, aviation, automotive, computer, inspection, and safety systems. A micro thrust and heat generator has a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator`s ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachine techniques (LIGA).

  9. 49. VIEW OF EAST SIDE OF LAUNCH PAD. THRUST SECTION ...

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

    49. VIEW OF EAST SIDE OF LAUNCH PAD. THRUST SECTION HEATER AND DUCTS ON RIGHT; UMBILICAL MAST POWER CONNECTORS ON LEFT; RAIL SYSTEM AND FIRE SUPPRESSION NOZZLES IN FOREGROUND. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  10. Army (MANTECH) thrust area concept: Optics thrust area

    NASA Astrophysics Data System (ADS)

    Kopacz, Stanley P.

    1992-04-01

    With the shrinking of the U.S. Army's material needs and the compression of defense requirements, the Army Manufacturing Technology (MANTECH) Program has the opportunity to advance the manufacturing state-of-the-art and solve near term production problems of the U.S. industrial base. To exploit this opportunity, the Army restructured its MANTECH efforts in FY 90 based on a thrust area concept. Each of the ten current thrusts, directed by a thrust area manager, has a broad technical objective selected to improve specific manufacturing processes. The manager is charged with setting objectives, selecting tasks, monitoring execution, leveraging external resources, and establishing microfactories to promote technology transfer. The Optics Manufacturing Thrust is an example of the concept. It is currently directed at revitalizing the domestic precision optics manufacturing base, now characterized by high labor costs and 1940's technology, through introduction of revolutionary machines, new processes, and Computer Integrated Manufacturing (CIM) principles. Leveraging of MANTECH dollars with those of industry, academia, and state governments led to the establishment of the center for Optics Manufacturing and plans for regional centers. Recognition of the U.S. as a world leader in precision optics manufacturing and a dramatic reduction of both manufacturing time and cost should accrue from thrust area efforts.

  11. Ag-Cu nanoalloyed film as a high-performance cathode electrocatalytic material for zinc-air battery

    NASA Astrophysics Data System (ADS)

    Lei, Yimin; Chen, Fuyi; Jin, Yachao; Liu, Zongwen

    2015-04-01

    A novel Ag50Cu50 film electrocatalyst for oxygen reduction reaction (ORR) was prepared by pulsed laser deposition (PLD) method. The electrocatalyst actually is Ag-Cu alloyed nanoparticles embedded in amorphous Cu film, based on transmission electron microscopy (TEM) characterization. The rotating disk electrode (RDE) measurements provide evidence that the ORR proceed via a four-electron pathway on the electrocatalysts in alkaline solution. And it is much more efficient than pure Ag catalyst. The catalytic layer has maximum power density of 67 mW cm-2 and an acceptable cell voltage at 0.863 V when current densities increased up to 100 mA cm-2 in the Ag50Cu50-based primary zinc-air battery. The resulting rechargeable zinc-air battery exhibits low charge-discharge voltage polarization of 1.1 V at 20 mAcm-2 and high durability over 100 cycles in natural air.

  12. Evaluation of fluidic thrust vectoring nozzle via thrust pitching angle and thrust pitching moment

    NASA Astrophysics Data System (ADS)

    Li, L.; Hirota, M.; Ouchi, K.; Saito, T.

    2016-03-01

    Shock vector control (SVC) in a converging-diverging nozzle with a rectangular cross-section is discussed as a fluidic thrust vectoring (FTV) method. The interaction between the primary nozzle flow and the secondary jet is examined using experiments and numerical simulations. The relationships between FTV parameters [nozzle pressure ratio (NPR) and secondary jet pressure ratio (SPR)] and FTV performance (thrust pitching angle and thrust pitching moment) are investigated. The experiments are conducted with an NPR of up to 10 and an SPR of up to 2.7. Numerical simulations of the nozzle flow are performed using a Navier-Stokes solver with input parameters set to match the experimental conditions. The thrust pitching angle and moment computed from the force-moment balance are used to evaluate FTV performance. The experiment and numerical results indicate that the FTV parameters (NPR and SPR) directly affect FTV performance. Conventionally, FTV performance evaluated by the common method using thrust pitching angle is highly dependent on the location of evaluation. Hence, in this study, we show that the thrust pitching moment, a parameter which is independent of the location, is the appropriate figure of merit to evaluate the performance of FTV systems.

  13. Uncertainty of in-flight thrust determination

    NASA Technical Reports Server (NTRS)

    Abernethy, Robert B.; Adams, Gary R.; Steurer, John W.; Ascough, John C.; Baer-Riedhart, Jennifer L.; Balkcom, George H.; Biesiadny, Thomas

    1986-01-01

    Methods for estimating the measurement error or uncertainty of in-flight thrust determination in aircraft employing conventional turbofan/turbojet engines are reviewed. While the term 'in-flight thrust determination' is used synonymously with 'in-flight thrust measurement', in-flight thrust is not directly measured but is determined or calculated using mathematical modeling relationships between in-flight thrust and various direct measurements of physical quantities. The in-flight thrust determination process incorporates both ground testing and flight testing. The present text is divided into the following categories: measurement uncertainty methodoogy and in-flight thrust measurent processes.

  14. Field calibration of rapidly equilibrating thin-film passive air samplers and their potential application for low-volume air sampling studies.

    PubMed

    Farrar, N J; Harner, T J; Sweetman, A J; Jones, K C

    2005-01-01

    This paper reports on a field calibration and ambient deployment study with rapidly equilibrating thin-film passive air samplers. POlymer-coated Glass (POG) samplers have a coating of ethylene vinyl acetate (EVA) less than 1 microm thick coated on to glass, which can be dissolved off after exposure and prepared for quantification of persistent organic pollutants (POPs) that have partitioned into the film during field exposure. In this study, POGs were exposed for up to 18 d, in a study to assess compound uptake rates and their time to approach equilibrium. Results confirmed theoretical predictions, with time to equilibrium varying between a few hours to ca. 20 d for PCB-18 and PCB-138, respectively. Performance reference compounds and contaminated POGs were used to investigate depuration kinetics, confirming that lighter congeners behave extremely dynamically with substantial losses from the films over periods of a few hours. Repeated deployments of the samplers for different3-d periods yielded detectable levels of a range of PCB congeners, which had partitioned from as little as approximately 2 to 10 m3 air. This highlights the potential utility of POGs for extremely sensitive and dynamic passive air sampling in the future to help improve understanding of sources, environmental fate, and behavior of POPs. Recommendations are made for future improvements/refinements in POG sampling and handling procedures.

  15. Analytic Modeling of the Hydrodynamic, Thermal, and Structural Behavior of Foil Thrust Bearings

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.; DellaCorte, Christopher; Prahl, Joseph M.

    2005-01-01

    A simulation and modeling effort is conducted on gas foil thrust bearings. A foil bearing is a self acting hydrodynamic device capable of separating stationary and rotating components of rotating machinery by a film of air or other gaseous lubricant. Although simple in appearance these bearings have proven to be complicated devices in analysis. They are sensitive to fluid structure interaction, use a compressible gas as a lubricant, may not be in the fully continuum range of fluid mechanics, and operate in the range where viscous heat generation is significant. These factors provide a challenge to the simulation and modeling task. The Reynolds equation with the addition of Knudsen number effects due to thin film thicknesses is used to simulate the hydrodynamics. The energy equation is manipulated to simulate the temperature field of the lubricant film and combined with the ideal gas relationship, provides density field input to the Reynolds equation. Heat transfer between the lubricant and the surroundings is also modeled. The structural deformations of the bearing are modeled with a single partial differential equation. The equation models the top foil as a thin, bending dominated membrane whose deflections are governed by the biharmonic equation. A linear superposition of hydrodynamic load and compliant foundation reaction is included. The stiffness of the compliant foundation is modeled as a distributed stiffness that supports the top foil. The system of governing equations is solved numerically by a computer program written in the Mathematica computing environment. Representative calculations and comparisons with experimental results are included for a generation I gas foil thrust bearing.

  16. Space shuttle orbit maneuvering engine reusable thrust chamber program

    NASA Technical Reports Server (NTRS)

    Senneff, J. M.

    1975-01-01

    Reusable thrust chamber and injector concepts were evaluated for the space shuttle orbit maneuvering engine (OME). Parametric engine calculations were carried out by computer program for N2O4/amine, LOX/amine and LOX/hydrocarbon propellant combinations for engines incorporating regenerative cooled and insulated columbium thrust chambers. The calculation methods are described including the fuel vortex film cooling method of combustion gas temperature control, and performance prediction. A method of acceptance of a regeneratively cooled heat rejection reduction using a silicone oil additive was also demonstrated by heated tube heat transfer testing. Regeneratively cooled thrust chamber operation was also demonstrated where the injector was characterized for the OME application with a channel wall regenerative thrust chamber. Bomb stability testing of the demonstration chambers/injectors demonstrated recovery for the nominal design of acoustic cavities. Cavity geometry changes were also evaluated to assess their damping margin. Performance and combustion stability was demonstrated of the originally developed 10 inch diameter combustion pattern operating in an 8 inch diameter thrust chamber.

  17. Formation of a Rigid Hydrophobin Film and Disruption by an Anionic Surfactant at an Air/Water Interface.

    PubMed

    Kirby, Stephanie M; Zhang, Xujun; Russo, Paul S; Anna, Shelley L; Walker, Lynn M

    2016-06-01

    Hydrophobins are amphiphilic proteins produced by fungi. Cerato-ulmin (CU) is a hydrophobin that has been associated with Dutch elm disease. Like other hydrophobins, CU stabilizes air bubbles and oil droplets through the formation of a persistent protein film at the interface. The behavior of hydrophobins at surfaces has raised interest in their potential applications, including use in surface coatings, food foams, and emulsions and as dispersants. The practical use of hydrophobins requires an improved understanding of the interfacial behavior of these proteins, alone and in the presence of added surfactants. In this study, the adsorption behavior of CU at air/water interfaces is characterized by measuring the surface tension and interfacial rheology as a function of adsorption time. CU is found to adsorb irreversibly at air/water interfaces. The magnitude of the dilatational modulus increases with adsorption time and surface pressure until CU eventually forms a rigid film. The persistence of this film is tested through the sequential addition of strong surfactant sodium dodecyl sulfate (SDS) to the bulk liquid adjacent to the interface. SDS is found to coadsorb to interfaces precoated with a CU film. At high concentrations, the addition of SDS significantly decreases the dilatational modulus, indicating disruption and displacement of CU by SDS. Sequential adsorption results in mixed layers with properties not observed in interfaces generated from complexes formed in the bulk. These results lend insight to the complex interfacial interactions between hydrophobins and surfactants. PMID:27164189

  18. Surface Partitioning and Stability of Mixed Films of Fluorinated Alcohols and Acids at the Air- Water Interface

    NASA Astrophysics Data System (ADS)

    Rontu, N. A.; Vaida, V.

    2007-05-01

    The production of fluorinated compounds over the past 50 years has had numerous industrial applications. For example, perfluorinated carboxylic acids are used in the synthesis of polymers and fire retardants, perfluoroalkyl sulfonates act as surface protectors, and fluorotelomer alcohols are incorporated into products such as paints, coatings, polymers, and adhesives. Fluorotelomer alcohols (FTOHs) are linear polyfluorinated alcohols with the formula CF3(CF2)nCH2CH2OH (n=1,3,5,...). They have been suggested as possible precursors for perfluorinated carboxylic acids and detected in the troposphere over several North American sites. Perfluorocarboxylic acids have even been detected in the arctic food chain, human blood, tissues of animals and environmental waters. We report the surface activity of fluorotelomer alcohols and perfluorinated carboxylic acids at the air-water interface by using a Langmuir trough. Isotherms of the pure compounds along with mixed films with other organic carboxylic acids were collected. The main objective of these experiments was to understand their heterogeneous chemistry by characterizing the pure and mixed films, which serves as a representative model for organic films on atmospheric surfaces such as those found on oceans and aqueous aerosols. Film properties and behavior, notably stabilization, evaporation from the subphase, and miscibility in the single-component mixtures as well as in the mixed films will be discussed. An important consequence of FTOHs and perfluorocarboxylic acids being found to partition to the air-water interface is the possibility of their transport and widespread distribution and deposition using atmospheric aerosols.

  19. Air-stable solution-processed n-channel organic thin film transistors with polymer-enhanced morphology

    SciTech Connect

    He, Zhengran; Shaik, Shoieb; Bi, Sheng; Li, Dawen; Chen, Jihua

    2015-05-04

    N,N′-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN{sub 2}) is an n-type semiconductor exhibiting high electron mobility and excellent air stability. However, the reported electron mobility based on spin-coated PDIF-CN{sub 2} film is much lower than the value of PDIF-CN{sub 2} single crystals made from vapor phase deposition, indicating significant room for mobility enhancement. In this study, various insulating polymers, including poly(vinyl alcohol), poly(methyl methacrylate) (PMMA), and poly(alpha-methylstyrene) (PαMS), are pre-coated on silicon substrate aiming to enhance the morphology of the PDIF-CN{sub 2} thin film, thereby improving the charge transport and air stability. Atomic force microscopy images reveal that with the pre-deposition of PαMS or PMMA polymers, the morphology of the PDIF-CN{sub 2} polycrystalline films is optimized in semiconducting crystal connectivity, domain size, and surface roughness, which leads to significant improvement of organic thin-film transistor (OTFT) performance. Particularly, an electron mobility of up to 0.55 cm{sup 2}/V s has been achieved from OTFTs based on the PDIF-CN{sub 2} film with the pre-deposition of PαMS polymer.

  20. Distribution and congener profiles of short-chain chlorinated paraffins in indoor/outdoor glass window surface films and their film-air partitioning in Beijing, China.

    PubMed

    Gao, Wei; Wu, Jing; Wang, Yawei; Jiang, Guibin

    2016-02-01

    Short-chain chlorinated paraffins (SCCPs) are a group of n-alkanes with carbon chain length of 10-13. In this work, paired indoor/outdoor samples of organic films on window glass surfaces from urban buildings in Beijing, China, were collected to measure the concentrations and congener distributions of SCCPs. The total SCCP levels ranged from 337 ng/m(2) to 114 μg/m(2), with total organic carbon (TOC) normalized concentrations of 365 μg/m(2)-365 mg/m(2). Overall, the concentrations of SCCPs on the interior films were higher than the concentrations on the exterior films, suggesting an important indoor environmental exposure of SCCPs to the general public. A significant linear relationship was found between the SCCP concentrations and TOC, with a correlation coefficient of R = 0.34 (p < 0.01). A film-air partitioning model suggests that the indoor gas-phase SCCPs are related to their corresponding window film levels.

  1. Post-burnout thrust measurements

    NASA Astrophysics Data System (ADS)

    McKenna, E. F.; Smith, H. T.

    1980-06-01

    Research was conducted into the problems of avoiding collision between separated payloads and spent rocket motors due to post burnout thrust, and the problem of contamination of scientific instrumentation due to outgassing of the smoldering insulation. The post burnout thrust was measured using a payload instrument module separated from an instrumented Black Brant VC Rocket in the exoatmosphere. In addition to measuring acceleration and velocities the spent motor was observed by a TV camera on board the command attitude controlled payload module. Analysis shows that the payload separated cleanly from the vehicle at a relative separation velocity of 0.69 m/sec, however the residual thrust of the spent motor overcame this differential, catching up to the payload 37 sec after separation and continuing on a parallel velocity vector at about 1.03 m/sec.

  2. Low thrust propulsion literature survey

    NASA Technical Reports Server (NTRS)

    Monroe, Darrel

    1989-01-01

    A literature search was performed to investigate the area of low thrust propulsion. In an effort to evaluate this technology, a number of articles, obtained through the use of the NASA-RECON database, were collected and categorized. The study indicates that although much was done, particularly in the 1960's and 1970's, more can be done in the area of practical navigation and guidance. It is suggested that the older studies be reinvestigated to see what potential there exists for future low thrust applications.

  3. Low Pressure DC Glow Discharge Air Plasma Surface Treatment of Polyethylene (PE) Film for Improvement of Adhesive Properties

    NASA Astrophysics Data System (ADS)

    Krishnasamy Navaneetha, Pandiyaraj; Vengatasamy, Selvarajan; Rajendrasing, R. Deshmukh; Paramasivam, Yoganand; Suresh, Balasubramanian; Sundaram, Maruthamuthu

    2013-01-01

    The present work deals with the change in surface properties of polyethylene (PE) film using DC low pressure glow discharge air plasma and makes it useful for technical applications. The change in hydrophilicity of the modified PE film surface was investigated by measuring contact angle and surface energy as a function of exposure time. Changes in the morphological and chemical composition of PE films were analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The improvement in adhesion was studied by measuring T-peel and lap-shear strength. The results show that the wettability and surface energy of the PE film has been improved due to the introduction of oxygen-containing polar groups and an increase in surface roughness. The XPS result clearly shows the increase in concentration of oxygen content and the formation of polar groups on the polymer surface. The AFM observation on PE film shows that the roughness of the surface increased due to plasma treatment. The above morphological and chemical changes enhanced the adhesive properties of the PE film surfaces, which was confirmed by T-peel and lap-shear tests.

  4. Surface treatment of polypropylene (PP) film by 50 Hz dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure

    SciTech Connect

    Joshi, Ujjwal Man Subedi, Deepak Prasad

    2015-07-31

    Thin films of polypropylene (PP) are treated for improving hydrophilicity using non-thermal plasma generated by 50 Hz line frequency dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure. PP samples before and after the treatments are studied using contact angle measurements, surface free energy calculations and scanning electron microscopy (SEM). Distilled water (H{sub 2}O), glycerol (C{sub 3}H{sub 8}O{sub 3}) and diiodomethane (CH{sub 2}I{sub 2}) are used as test liquids. The contact angle measurements between test liquids and PP samples are used to determine total surface free energy using sessile drop technique. PP films show a remarkable increase in surface free energy after plasma treatment. SEM analysis of the plasma-treated PP films shows that plasma treatment introduces greater roughness on the surface leading to the increased surface free energy. Furthermore, it is found that introducing a small quantity of argon can enhance the surface treatment remarkably.

  5. Internal performance characteristics of thrust-vectored axisymmetric ejector nozzles

    NASA Technical Reports Server (NTRS)

    Lamb, Milton

    1995-01-01

    A series of thrust-vectored axisymmetric ejector nozzles were designed and experimentally tested for internal performance and pumping characteristics at the Langley research center. This study indicated that discontinuities in the performance occurred at low primary nozzle pressure ratios and that these discontinuities were mitigated by decreasing expansion area ratio. The addition of secondary flow increased the performance of the nozzles. The mid-to-high range of secondary flow provided the most overall improvements, and the greatest improvements were seen for the largest ejector area ratio. Thrust vectoring the ejector nozzles caused a reduction in performance and discharge coefficient. With or without secondary flow, the vectored ejector nozzles produced thrust vector angles that were equivalent to or greater than the geometric turning angle. With or without secondary flow, spacing ratio (ejector passage symmetry) had little effect on performance (gross thrust ratio), discharge coefficient, or thrust vector angle. For the unvectored ejectors, a small amount of secondary flow was sufficient to reduce the pressure levels on the shroud to provide cooling, but for the vectored ejector nozzles, a larger amount of secondary air was required to reduce the pressure levels to provide cooling.

  6. Effects of thrust reversing in ground proximity

    NASA Technical Reports Server (NTRS)

    Joshi, P. B.; Hughes, R. V.

    1987-01-01

    The changes in stability and control characteristics encountered by a thrust reversing aircraft during its final approach, landing, and ground roll are described. These changes include a strong pitch-up accompanied by the loss of horizontal tail and aileron control effectiveness. The magnitude of reverser induced changes in ground effect are much larger than corresponding changes in free air. Some unexpected unsteady motions exhibited in wind tunnel by an aircraft model with reversers operating in ground proximity are also described. The cause of this oscillatory behavior was determined to be an unsteady interaction between the wall jets formed by impingement of reverser jets on the ground and the on-coming free stream. Time histories of rolling moments measured by the wind tunnel balance or support system were removed and frequencies were scaled by Strouhal number to full scale. Corrected time series were used to simulate the motion of a fighter aircraft with thrust reversers in ground effect. The simulation predicted large roll angles and nose down attitude at touchdown. Some phenomena of jet attachment to solid surfaces are discussed and areas for future research are recommended.

  7. Characterization of composite phthalocyanine-fatty acid films from the air/water interface to solid supports.

    PubMed

    Giancane, G; Manno, D; Serra, A; Sgobba, V; Valli, L

    2011-12-22

    A commercial vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine (VOPc) was dissolved in chloroform and spread on ultrapure water subphase in a Langmuir trough. The floating film was thoroughly characterized at the air-water interface by means of the Langmuir isotherm, Brewster angle microscopy, UV-vis reflection spectroscopy, and infrared measurements carried out directly at the air-water interface. All the results showed the formation of a non-uniform and aggregated floating layer, too rigid to be transferred by the Langmuir-Blodgett (LB) method. For this reason, a mixture of arachidic acid and VOPc was realized, characterized, and transferred by the LB technique on solid substrates. Interface measurements and atomic force microscopy analysis suggested the formation of a uniform arachidic acid film and a superimposed VOPc placed in prone configuration.

  8. Another Look at Rocket Thrust

    ERIC Educational Resources Information Center

    Hester, Brooke; Burris, Jennifer

    2012-01-01

    Rocket propulsion is often introduced as an example of Newton's third law. The rocket exerts a force on the exhaust gas being ejected; the gas exerts an equal and opposite force--the thrust--on the rocket. Equivalently, in the absence of a net external force, the total momentum of the system, rocket plus ejected gas, remains constant. The law of…

  9. Carbon nanotube film synthesized from ethanol and its oxidation behavior in air

    NASA Astrophysics Data System (ADS)

    Ren, Yan; Ma, Wen-Jun; Zeng, Qing-Sheng; Li, Jin-Zhu; Dong, Hai-Bo; Zhou, Wei-Ya

    2012-09-01

    In this paper, we propose an efficient way to synthesize carbon nanotube films using ferrocene and ethanol. The as-grown film is free-standing, semi-transparent, and of macro scale size. The tubes in the film are mostly single- or double-walled. The oxidation behavior of the film is studied via Raman spectroscopy, and the result indicates that the inner wall of the double-walled tube is effectively protected from oxidation by the outer wall.

  10. Pulsed Electric Propulsion Thrust Stand Calibration Method

    NASA Technical Reports Server (NTRS)

    Wong, Andrea R.; Polzin, Kurt A.; Pearson, J. Boise

    2011-01-01

    The evaluation of the performance of any propulsion device requires the accurate measurement of thrust. While chemical rocket thrust is typically measured using a load cell, the low thrust levels associated with electric propulsion (EP) systems necessitate the use of much more sensitive measurement techniques. The design and development of electric propulsion thrust stands that employ a conventional hanging pendulum arm connected to a balance mechanism consisting of a secondary arm and variable linkage have been reported in recent publications by Polzin et al. These works focused on performing steady-state thrust measurements and employed a static analysis of the thrust stand response. In the present work, we present a calibration method and data that will permit pulsed thrust measurements using the Variable Amplitude Hanging Pendulum with Extended Range (VAHPER) thrust stand. Pulsed thrust measurements are challenging in general because the pulsed thrust (impulse bit) occurs over a short timescale (typically 1 micros to 1 millisecond) and cannot be resolved directly. Consequently, the imparted impulse bit must be inferred through observation of the change in thrust stand motion effected by the pulse. Pulsed thrust measurements have typically only consisted of single-shot operation. In the present work, we discuss repetition-rate pulsed thruster operation and describe a method to perform these measurements. The thrust stand response can be modeled as a spring-mass-damper system with a repetitive delta forcing function to represent the impulsive action of the thruster.

  11. Properties of the seawater-air interface. 2. Rates of surface film formation under steady state conditions

    SciTech Connect

    Dragcevic, D.; Pravdic, V.

    1981-05-01

    The laboratory techniques of dynamic surface tension and of surface electrical potential measurements were used to determine rates of formation and of reorientation of organic surface films at the seawater-air interface. Relaxation times of surface films were determined for three characteristic samples obtained by screen and bottle sampling in the coastal waters of the northern Adriatic area. These data were compared with those for model samples produced by spreading oleic acid and crude oil on or dissolving polyethyleneglycol and sodium dodecyl sulfate in artificial seawater. Relaxation times were in the range of 0.1-1 s for most of the samples. A good representative value for field samples is 0.2 s. The temperature-dependence (the energies of activation) for the surface film relaxation indicates that several processes control material transport toward the seawater-air interface. The findings are interpreted as showing that an almost ever-present organic surface film influences the mechanism and the rate of material transport across the sea-atmosphere boundary.

  12. Bonding of SU-8 films onto KMPR structures for microfluidic, air-suspended photonic and optofluidic applications

    NASA Astrophysics Data System (ADS)

    Prokop, Christoph; Schoenhardt, Steffen; Mahmud, Tanveer; Mitchell, Arnan; Karnutsch, Christian

    2016-05-01

    We present a method to bond unstructured and structured SU-8 films down to sub-micron thicknesses onto microchannels fabricated in KMPR using a flexible polydimethylsiloxane (PDMS) stamp. By exploiting differently casted PDMS stamps, 3D microfluidic channel networks, air-suspended photonic devices and optofluidic structures have been fabricated. First, microchannels of KMPR are patterned by photolithography and an SU-8 film is spin coated onto a prepared PDMS stamp. The stamp is then placed on top of the KMPR microchannels and the SU-8 layer is cross-linked by applying sufficient heat and pressure. After peeling off the PDMS stamp, the SU-8 layer remains bonded on the KMPR. In our experiments, we demonstrate the bonding of approximately 0.5 μm thick structured SU-8 films onto KMPR microchannels of about 500 μm width and 25 μm height. Bond strength tests demonstrated that such thin layers can withstand pressures up to 1100 hPa. The laminated SU-8 layers can enable various functionalities, e.g. sealing of microfluidic channels, realization of air-suspended photonic structures or optofluidic devices. Most importantly, the combination of fluid handling in the microchannels and air-suspended photonic structures realized in the laminated SU-8 layer enables research towards a large range of applications, such as optofluidics, biosensors, chemical and biomedical analysis, environmental investigations, and renewable energy.

  13. Decomposition of benzene and toluene in air streams in fixed-film photoreactors coated with TiO2 catalyst.

    PubMed

    Ku, Young; Chen, Juan-Shiang; Chen, Hua-Wei

    2007-03-01

    The decomposition of benzene and toluene in air streams by UV/TiO2 process was studied in different annular photoreactors under various operating conditions. The shells of reactors used in this research are made of stainless steel, Pyrex glass, or titanium. The TiO2 film was coated to the inner surface of the reactors by either rotating coating or sol-gel techniques. The TiO2 films coated by sol-gel technique were found to be smoother and more uniform than those coated by rotating coating. However, experimental results indicated that the photocatalysis of benzene or toluene in a glass reactor with rotating-coated TiO2 film delivered higher decompositions in air streams than that with sol-gel coated reactors. Benzene and toluene were decomposed more effectively in a coated glass reactor than in a coated stainless steel reactor under the same operating conditions. The presence of water vapor in air-stream plays an important role in the decomposition of benzene and toluene, and a relative humidity of approximately 5-6% was found to be adequate. The presence of excessive amounts of humidity retarded the decomposition to certain extents possibly results from the competitive adsorption of water molecules on the active sites of TiO2.

  14. Measuring forces and spatiotemporal evolution of thin water films between an air bubble and solid surfaces of different hydrophobicity.

    PubMed

    Shi, Chen; Cui, Xin; Xie, Lei; Liu, Qingxia; Chan, Derek Y C; Israelachvili, Jacob N; Zeng, Hongbo

    2015-01-27

    A combination of atomic force microscopy (AFM) and reflection interference contrast microscopy (RICM) was used to measure simultaneously the interaction force and the spatiotemporal evolution of the thin water film between a bubble in water and mica surfaces with varying degrees of hydrophobicity. Stable films, supported by the repulsive van der Waals-Casimir-Lifshitz force were always observed between air bubble and hydrophilic mica surfaces (water contact angle, θ(w) < 5°) whereas bubble attachment occurred on hydrophobized mica surfaces. A theoretical model, based on the Reynolds lubrication theory and the augmented Young-Laplace equation including the effects of disjoining pressure, provided excellent agreement with experiment results, indicating the essential physics involved in the interaction between air bubble and solid surfaces can be elucidated. A hydrophobic interaction free energy per unit area of the form: WH(h) = -γ(1 - cos θ(w))exp(-h/D(H)) can be used to quantify the attraction between bubble and hydrophobized solid substrate at separation, h, with γ being the surface tension of water. For surfaces with water contact angle in the range 45° < θ(w) < 90°, the decay length DH varied between 0.8 and 1.0 nm. This study quantified the hydrophobic interaction in asymmetric system between air bubble and hydrophobic surfaces, and provided a feasible method for synchronous measurements of the interaction forces with sub-nN resolution and the drainage dynamics of thin films down to nm thickness.

  15. Measuring forces and spatiotemporal evolution of thin water films between an air bubble and solid surfaces of different hydrophobicity.

    PubMed

    Shi, Chen; Cui, Xin; Xie, Lei; Liu, Qingxia; Chan, Derek Y C; Israelachvili, Jacob N; Zeng, Hongbo

    2015-01-27

    A combination of atomic force microscopy (AFM) and reflection interference contrast microscopy (RICM) was used to measure simultaneously the interaction force and the spatiotemporal evolution of the thin water film between a bubble in water and mica surfaces with varying degrees of hydrophobicity. Stable films, supported by the repulsive van der Waals-Casimir-Lifshitz force were always observed between air bubble and hydrophilic mica surfaces (water contact angle, θ(w) < 5°) whereas bubble attachment occurred on hydrophobized mica surfaces. A theoretical model, based on the Reynolds lubrication theory and the augmented Young-Laplace equation including the effects of disjoining pressure, provided excellent agreement with experiment results, indicating the essential physics involved in the interaction between air bubble and solid surfaces can be elucidated. A hydrophobic interaction free energy per unit area of the form: WH(h) = -γ(1 - cos θ(w))exp(-h/D(H)) can be used to quantify the attraction between bubble and hydrophobized solid substrate at separation, h, with γ being the surface tension of water. For surfaces with water contact angle in the range 45° < θ(w) < 90°, the decay length DH varied between 0.8 and 1.0 nm. This study quantified the hydrophobic interaction in asymmetric system between air bubble and hydrophobic surfaces, and provided a feasible method for synchronous measurements of the interaction forces with sub-nN resolution and the drainage dynamics of thin films down to nm thickness. PMID:25514470

  16. Two dimensional cold air cascade study of a film cooled turbine stator blade. 2: Experimental results of full film cooling tests

    NASA Technical Reports Server (NTRS)

    Prust, H. W., Jr.

    1975-01-01

    The effect of full film cooling on the performance of a turbine stator blade was studied in a two-dimensional cascade. The blade contained 12 rows of coolant holes, 6 rows on the suction surface and 6 on the pressure surface. Separate tests were first made with coolant ejection from each of the 12 rows. Then successive tests were made with various combinations of coolant rows open, including full film cooling. The principal results are presented in terms of primary-air efficiency as a function of coolant fraction. In addition, the efficiency results of the multirow tests are compared with the multi-row efficiency predicted by adding the single-row results.

  17. 14 CFR 33.97 - Thrust reversers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .... This test may be scheduled as part of the endurance run. (b) 175 reversals must be made from flight-idle forward thrust to maximum reverse thrust and 25 reversals must be made from rated takeoff...

  18. 14 CFR 33.97 - Thrust reversers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... This test may be scheduled as part of the endurance run. (b) 175 reversals must be made from flight-idle forward thrust to maximum reverse thrust and 25 reversals must be made from rated takeoff...

  19. 14 CFR 33.97 - Thrust reversers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... This test may be scheduled as part of the endurance run. (b) 175 reversals must be made from flight-idle forward thrust to maximum reverse thrust and 25 reversals must be made from rated takeoff...

  20. 14 CFR 33.97 - Thrust reversers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .... This test may be scheduled as part of the endurance run. (b) 175 reversals must be made from flight-idle forward thrust to maximum reverse thrust and 25 reversals must be made from rated takeoff...

  1. Controllable Growth of Perovskite Films by Room-Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells

    SciTech Connect

    Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; Keum, Jong; Das, Sanjib; Puretzky, Alexander; Aytug, Tolga; Joshi, Pooran C.; Rouleau, Christopher M.; Duscher, Gerd; Geohegan, David B.; Xiao, Kai

    2015-12-01

    A two-step-solution-processing approach has been established to grow void-free perovskite films for low-cost and high-performance planar heterojunction photovoltaic devices. We generally applied a high-temperature thermal annealing treatment in order to drive the diffusion of CH3NH3I precursor molecules into the compact PbI2 layer to form perovskite films. But, thermal annealing for extended periods would lead to degraded device performance due to the defects generated by decomposition of perovskite into PbI2. In this work, we explored a controllable layer-by-layer spin-coating method to grow bilayer CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple room-temperature-air-exposure for making well-oriented, highly-crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ~ 800 nm and high device efficiency of 15.6%, which is comparable to the reported values from thermally-annealed perovskite films based counterparts. Finally, the simplicity and high device performance of this processing approach is highly promising for direct integration into industrial-scale device manufacture.

  2. Controllable Growth of Perovskite Films by Room-Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells

    DOE PAGES

    Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; Keum, Jong; Das, Sanjib; Puretzky, Alexander; Aytug, Tolga; Joshi, Pooran C.; Rouleau, Christopher M.; Duscher, Gerd; et al

    2015-12-01

    A two-step-solution-processing approach has been established to grow void-free perovskite films for low-cost and high-performance planar heterojunction photovoltaic devices. We generally applied a high-temperature thermal annealing treatment in order to drive the diffusion of CH3NH3I precursor molecules into the compact PbI2 layer to form perovskite films. But, thermal annealing for extended periods would lead to degraded device performance due to the defects generated by decomposition of perovskite into PbI2. In this work, we explored a controllable layer-by-layer spin-coating method to grow bilayer CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple room-temperature-air-exposure for makingmore » well-oriented, highly-crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ~ 800 nm and high device efficiency of 15.6%, which is comparable to the reported values from thermally-annealed perovskite films based counterparts. Finally, the simplicity and high device performance of this processing approach is highly promising for direct integration into industrial-scale device manufacture.« less

  3. Controllable Growth of Perovskite Films by Room-Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells.

    PubMed

    Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; Keum, Jong; Das, Sanjib; Puretzky, Alexander; Aytug, Tolga; Joshi, Pooran C; Rouleau, Christopher M; Duscher, Gerd; Geohegan, David B; Xiao, Kai

    2015-12-01

    A two-step solution processing approach has been established to grow void-free perovskite films for low-cost high-performance planar heterojunction photovoltaic devices. A high-temperature thermal annealing treatment was applied to drive the diffusion of CH3NH3I precursor molecules into a compact PbI2 layer to form perovskite films. However, thermal annealing for extended periods led to degraded device performance owing to the defects generated by decomposition of perovskite into PbI2. A controllable layer-by-layer spin-coating method was used to grow "bilayer" CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple air exposure at room temperature for making well-oriented, highly crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ca. 800 nm and a high device efficiency of 15.6%, which is comparable to values reported for thermally annealed perovskite films.

  4. Controllable Growth of Perovskite Films by Room-Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells.

    PubMed

    Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; Keum, Jong; Das, Sanjib; Puretzky, Alexander; Aytug, Tolga; Joshi, Pooran C; Rouleau, Christopher M; Duscher, Gerd; Geohegan, David B; Xiao, Kai

    2015-12-01

    A two-step solution processing approach has been established to grow void-free perovskite films for low-cost high-performance planar heterojunction photovoltaic devices. A high-temperature thermal annealing treatment was applied to drive the diffusion of CH3NH3I precursor molecules into a compact PbI2 layer to form perovskite films. However, thermal annealing for extended periods led to degraded device performance owing to the defects generated by decomposition of perovskite into PbI2. A controllable layer-by-layer spin-coating method was used to grow "bilayer" CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple air exposure at room temperature for making well-oriented, highly crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ca. 800 nm and a high device efficiency of 15.6%, which is comparable to values reported for thermally annealed perovskite films. PMID:26486584

  5. Growth of CdS thin films on indium coated glass substrates via chemical bath deposition and subsequent air annealing

    NASA Astrophysics Data System (ADS)

    Ghosh, Biswajit; Kumar, Kamlesh; Singh, Balwant Kr; Banerjee, Pushan; Das, Subrata

    2014-11-01

    In the present work attempts were made to synthesize indium doped CdS films by fabricating In/CdS bilayers using CBD-CdS on vacuum evaporated In thin films and subsequent air annealing. 135 nm CdS films were grown onto 20 nm and 35 nm indium coated glass substrate employing chemical bath deposition technique. The In/CdS bilayers thus formed were subjected to heat treatment at the temperatures between 200 and 400 °C for 4 min in the muffle furnace to facilitate indium to diffuse into the CdS films. XRD pattern ascertained no noticeable shift in lattice constant implying grain boundary metal segregation, while secondary ion mass spectrometry indicated the diffusion profile of indium into CdS matrices. Mass spectrometry results showed that substantial diffusion of indium had been taken place within CdS at 400 °C. Dark and photocurrent with different illumination time were measured to ascertain the photosensitivity of pure and composite CdS films.

  6. Two-dimensional cold-air cascade study of a film-cooled turbine stator blade. 1: Experimental results of pressure-surface film cooling tests

    NASA Technical Reports Server (NTRS)

    Moffitt, T. P.; Prust, H. W., Jr.; Bartlett, W. M.

    1974-01-01

    The effect of film coolant ejection from the pressure side of a stator blade was determined in a two-dimensional cascade. Stator exit surveys were made for each of six rows of coolant holes. Successive multirow tests were made with two, three, four, five, and six rows of coolant holes open. The results of the multirow tests are compared with the predicted multirow performance obtained by adding the single-row data. Results are presented in terms of stator primary-air efficiency as a function of coolant fraction.

  7. An approach to evaluate capacitance, capacitive reactance and resistance of pivoted pads of a thrust bearing

    NASA Astrophysics Data System (ADS)

    Prashad, Har

    1992-07-01

    A theoretical approach is developed for determining the capacitance and active resistance between the interacting surfaces of pivoted pads and thrust collar, under different conditions of operation. It is shown that resistance and capacitive reactance of a thrust bearing decrease with the number of pads times the values of these parameters for an individual pad, and that capacitance increases with the number of pads times the capacitance of an individual pad. The analysis presented has a potential to diagnose the behavior of pivoted pad thrust bearings with the angle of tilt and the ratio of film thickness at the leading to trailing edge, by determining the variation of capacitance, resistance, and capacitive reactance.

  8. Low thrust orbit determination program

    NASA Technical Reports Server (NTRS)

    Hong, P. E.; Shults, G. L.; Huling, K. R.; Ratliff, C. W.

    1972-01-01

    Logical flow and guidelines are provided for the construction of a low thrust orbit determination computer program. The program, tentatively called FRACAS (filter response analysis for continuously accelerating spacecraft), is capable of generating a reference low thrust trajectory, performing a linear covariance analysis of guidance and navigation processes, and analyzing trajectory nonlinearities in Monte Carlo fashion. The choice of trajectory, guidance and navigation models has been made after extensive literature surveys and investigation of previous software. A key part of program design relied upon experience gained in developing and using Martin Marietta Aerospace programs: TOPSEP (Targeting/Optimization for Solar Electric Propulsion), GODSEP (Guidance and Orbit Determination for SEP) and SIMSEP (Simulation of SEP).

  9. Low Temperature Fabrication of REBa2Cu3Oy Epitaxial Films on SrTiO3 (100) Substrate Prepared by Molten Hydroxide Method in 1-atm Air

    NASA Astrophysics Data System (ADS)

    Funaki, S.; Yamada, Y.; Miyachi, Y.; Okunishi, R.

    In order to establish the fabrication method of high-Tc REBa2Cu3Oy (RE123) films by feasible simple system, we fabricated the RE123 films on SrTiO3 substrate by molten hydroxide method in low temperature and 1-atm air. Obtain films of RE-123 (RE = Gd, Eu, Sm) fabricated at low temperature of 525 °C show a c-axis orientation of RE123 and REBa2Cu4O8 phases. Moreover, the Nd-123 films show a bi-axial orientation of Nd123 single phase completely above 425 °C. The Tconset of Nd123 film fabricated at 525 °C denotes 67.1 K which was drastically lower compared with previous study of Nd123 single crystalline film, and Tconset of Nd123 films degrade with decreasing fabrication temperature. We can consider that the Nd/Ba substitution was caused by lowering the fabrication temperature.

  10. Parametric Investigation of Thrust Augmentation by Ejectors on a Pulsed Detonation Tube

    NASA Technical Reports Server (NTRS)

    Wilson, Jack; Sgondea, Alexandru; Paxson, Daniel E.; Rosenthal, Bruce N.

    2005-01-01

    A parametric investigation has been made of thrust augmentation of a 1 inch diameter pulsed detonation tube by ejectors. A set of ejectors was used which permitted variation of the ejector length, diameter, and nose radius, according to a statistical design of experiment scheme. The maximum augmentations for each ejector were fitted using a polynomial response surface, from which the optimum ejector diameters, and nose radius, were found. Thrust augmentations above a factor of 2 were measured. In these tests, the pulsed detonation device was run on approximately stoichiometric air-hydrogen mixtures, at a frequency of 20 Hz. Later measurements at a frequency of 40 Hz gave lower values of thrust augmentation. Measurements of thrust augmentation as a function of ejector entrance to detonation tube exit distance showed two maxima, one with the ejector entrance upstream, and one downstream, of the detonation tube exit. A thrust augmentation of 2.5 was observed using a tapered ejector.

  11. Band gap shift in the indium-tin-oxide films on polyethylene napthalate after thermal annealing in air

    NASA Astrophysics Data System (ADS)

    Han, H.; Mayer, J. W.; Alford, T. L.

    2006-10-01

    Indium-tin-oxide (ITO) thin films on polyethylene napthalate (PEN) with high carrier concentration (˜1021/cm3) have been grown by electron-beam deposition without the introduction of oxygen into the chamber. The electrical properties of the ITO films (such as, carrier concentration, electrical mobility, and resistivity) abruptly changed after annealing in the air atmospheres. In addition, optical transmittance and optical band gap values significantly changed after heat treatment. The optical band gap narrowing behavior is observed in the as-deposited sample because of impurity band and heavy carrier concentration. The influence of annealing in air on the electrical and optical properties of ITO/PEN samples can be explained by the change in the free electron concentration, which is evaluated in terms of the oxygen content. Rutherford backscattering spectrometry and x-ray photoelectron spectroscopy analyses are used to determine the oxygen content in the film. Hall effect measurements are used to determine the dependence of electrical properties on oxygen content.

  12. Liquid Surface X-ray Studies of Gold Nanoparticle-Phospholipid Films at the Air/Water Interface.

    PubMed

    You, Siheng Sean; Heffern, Charles T R; Dai, Yeling; Meron, Mati; Henderson, J Michael; Bu, Wei; Xie, Wenyi; Lee, Ka Yee C; Lin, Binhua

    2016-09-01

    Amphiphilic phospholipids and nanoparticles functionalized with hydrophobic capping ligands have been extensively investigated for their capacity to self-assemble into Langmuir monolayers at the air/water interface. However, understanding of composite films consisting of both nanoparticles and phospholipids, and by extension, the complex interactions arising between nanomaterials and biological membranes, remains limited. In this work, dodecanethiol-capped gold nanoparticles (Au-NPs) with an average core diameter of 6 nm were incorporated into 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers with surface densities ranging from 0.1 to 20% area coverage at a surface pressure of 30 mN/m. High resolution liquid surface X-ray scattering studies revealed a phase separation of the DPPC and Au-NP components of the composite film, as confirmed with atomic force microscopy after the film was transferred to a substrate. At low Au-NP content, the structural organization of the phase-separated film is best described as a DPPC film containing isolated islands of Au-NPs. However, increasing the Au-NP content beyond 5% area coverage transforms the structural organization of the composite film to a long-range interconnected network of Au-NP strands surrounding small seas of DPPC, where the density of the Au-NP network increases with increasing Au-NP content. The observed phase separation and structural organization of the phospholipid and nanoparticle components in these Langmuir monolayers are useful for understanding interactions of nanoparticles with biological membranes. PMID:27459364

  13. On Film

    ERIC Educational Resources Information Center

    Watts, Marty

    2006-01-01

    In this article, the author discusses the role of window films in enhancing indoor air quality in schools. Historically, window film has been used to reduce temperatures in buildings prone to overheating. Too much solar energy entering through windows makes occupants uncomfortable and air conditioning more costly. Film has been a simple solution…

  14. Ag-Cu nanoalloyed film as a high-performance cathode electrocatalytic material for zinc-air battery.

    PubMed

    Lei, Yimin; Chen, Fuyi; Jin, Yachao; Liu, Zongwen

    2015-01-01

    A novel Ag50Cu50 film electrocatalyst for oxygen reduction reaction (ORR) was prepared by pulsed laser deposition (PLD) method. The electrocatalyst actually is Ag-Cu alloyed nanoparticles embedded in amorphous Cu film, based on transmission electron microscopy (TEM) characterization. The rotating disk electrode (RDE) measurements provide evidence that the ORR proceed via a four-electron pathway on the electrocatalysts in alkaline solution. And it is much more efficient than pure Ag catalyst. The catalytic layer has maximum power density of 67 mW cm(-2) and an acceptable cell voltage at 0.863 V when current densities increased up to 100 mA cm(-2) in the Ag50Cu50-based primary zinc-air battery. The resulting rechargeable zinc-air battery exhibits low charge-discharge voltage polarization of 1.1 V at 20 mAcm(-2) and high durability over 100 cycles in natural air. PMID:25977668

  15. VERIFICATION OF INDICATED SKIN ENTRANCE AIR KERMA FOR CARDIAC X-RAY-GUIDED INTERVENTION USING GAFCHROMIC FILM.

    PubMed

    Nilsson Althén, J; Sandborg, M

    2016-06-01

    The aim of this work was to verify the indicated maximum entrance surface air kerma (ESAK) using a GE Innova IGS 520 imaging system during cardiac interventional procedures. Gafchromic XR RV3 films were used for the patient measurements to monitor the maximum ESAK. The films were scanned and calibrated to measure maximum ESAK. Thermoluminescent dosemeters were used to measure the backscatter factor from an anthropomorphic thorax phantom. The measured backscatter factor, 1.53, was in good agreement with Monte Carlo simulations but higher than the one used by the imaging system, 1.20. The median of the ratio between indicated maximum ESAK and measured maximum ESAK was 0.68. In this work, the indicated maximum ESAK by the imaging system's dose map model underestimates the measured maximum ESAK by 32 %. The threshold ESAK for follow-up procedures for patient with skin dose in excess of 2 Gy will be reduced to 1.4 Gy. PMID:26541185

  16. Characerization of photosynthetic reaction centres from Rhodobacter sphaeroides at the air-water interface and in Langmuir-Blodgett films

    SciTech Connect

    Fang, J.Y.; Gaul, D.F.; Chumanov, G.; Cotton, T.M.; Uphaus, R.A. |

    1995-11-01

    Monolayers of the reaction center complex from Rhodobacter sphaeroides were prepared from dodecyl {Beta}-maltoside suspensions at an air-water interface. The stability of these monolayers was determined. A value of 28 nm{sup 2} per complex was obtained for the cross-sectional area from the equilibrium surface pressure-area isotherms. Multilayer films of alternating arachidic acid-reaction center monolayers were constructed on quartz slides by the Langmuir-Blodgett technique. Absorption spectroscopy was used to confirm the structural integrity of the complex and to determine the transfer ratio. Low-angle X-ray diffraction measurements were performed on these multilayers. A value of 64 A was obtained for the thickness of the reaction center monolayer in the multilayer film. This novel approach can be used to study multilayers of other membrane-bound proteins. 20 refs., 9 figs.

  17. Modular multi-engine thrust control assembly

    SciTech Connect

    Sakurai, S.

    1986-02-04

    This patent describes a modular thrust control lever assembly for controling forward/reverse thrust generated by an aircraft engine. It includes an electric/electronic engine thrust control system, an inhibit mechanism for preventing inadverent or premature establishment of at least one of forward and reverse engine thrust. It consists of a (a) housing; (b) a control lever assembly pivotally mounted within the housing for fore and aft pivotal movement in a single vertical plane; (c) movable inhibit mechanism normally mounted in the path of movement of the laterally projecting roller on the control lever assembly between at least one of the maximum thrust limit positions of the assembly and the adjacent intermediate idle thrust position; (d) a electric/electronic engine thrust control system including an mechanism for reconfiguring the thrust controls of the engine upon movement of the thrust control lever assembly to the adjacent intermediate idle thrust position; (e) a mechanism responsive to the output signal for shifting the inhibit mechanism out of the path of movement of the control lever assembly.

  18. Influence of coolant injector configuration on film cooling effectiveness for gaseous and liquid film coolants

    NASA Astrophysics Data System (ADS)

    Shine, S. R.; Sunil Kumar, S.; Suresh, B. N.

    2012-05-01

    An experimental investigation is conducted to bring out the effects of coolant injector configuration on film cooling effectiveness, film cooled length and film uniformity associated with gaseous and liquid coolants. A series of measurements are performed using hot air as the core gas and gaseous nitrogen and water as the film coolants in a cylindrical test section simulating a thrust chamber. Straight and compound angle injection at two different configurations of 30°-10° and 45°-10° are investigated for the gaseous coolant. Tangential injection at 30° and compound angle injection at 30°-10° are examined for the liquid coolant. The analysis is based on measurements of the film-cooling effectiveness and film uniformity downstream of the injection location at different blowing ratios. Measured results showed that compound angle configuration leads to lower far-field effectiveness and shorter film length compared to tangential injection in the case of liquid film cooling. For similar injector configurations, effectiveness along the stream wise direction showed flat characteristics initially for the liquid coolant, while it was continuously dropping for the gaseous coolant. For liquid coolant, deviations in temperature around the circumference are very low near the injection point, but increases to higher values for regions away from the coolant injection locations. The study brings out the existance of an optimum gaseous film coolant injector configuration for which the effectiveness is maximum.

  19. Synthesis of perm-selective membranes by grafting acrylic acid into air-irradiated Teflon-FEP films

    NASA Astrophysics Data System (ADS)

    Bozzi, Annick; Chapiro, Adolphe

    Grafting acrylic acid into air-irradiated Teflon-FEP films was investigated. Pre-irradiation doses ranged from 0.5 to 10 kGy. Grafting occurred at 45 or 60°C. Homopolymerization inhibitors, ferrous ions or methylene blue, were added to the system. It was found that after completion of the reaction, within 40-100 min, membranes were obtained with very low electric resistivities. The influence of added inhibitors, pre-irradiation dose and grafting temperature was studied. From the results it is concluded that the initiating centers in air-irradiated Teflon-FEP are, on the one hand, peroxides of structure POOP', in which P is a polymeric radical and Pprime; a small fragment, and on the other trapped PO .2 radicals. The latter only react after losing their oxygen. In the presence of polymerization inhibitors, initiation involves a redox process which reduces the overall activation energy.

  20. An investigation of high performance, short thrust augmenting ejectors

    NASA Astrophysics Data System (ADS)

    Yang, T.; Jiang, T.; Pitts, D. R.; Ntone, F.

    1984-12-01

    The design of air-to-air, thrust augmenting ejectors having short curved wall diffusers utilizing boundary layer control is discussed. The design is achieved by an inverse method which uses the vorticity at the diffuser inlet as a flow parameter in the analysis. Three diffusers having ejector length-to-mixing chamber diameter ratios of approximately 6:1 and mixing chamber inlet area-to-primary nozzle area ratios of 20:1 and 40:1 were designed and tested. A new high level of performance was analytically predicted and achieved experimentally. Comparisons between predicted and observed performances, velocity distributions and pressure distributions are presented.

  1. Internal-liquid-film-cooling Experiments with Air-stream Temperatures to 2000 Degrees F. in 2- and 4-inch-diameter Horizontal Tubes

    NASA Technical Reports Server (NTRS)

    Kinney, George R; Abramson, Andrew E; Sloop, John L

    1952-01-01

    Report presents the results of an investigation conducted to determine the effectiveness of liquid-cooling films on the inner surfaces of tubes containing flowing hot air. Experiments were made in 2- and 4-inch-diameter straight metal tubes with air flows at temperatures from 600 degrees to 2000 degrees F. and diameter Reynolds numbers from 2.2 to 14 x 10(5). The film coolant, water, was injected around the circumference at a single axial position on the tubes at flow rates from 0.02 to .24 pound per second per foot of tube circumference (0.8 to 12 percent of the air flow). Liquid-coolant films were established and maintained around and along the tube wall in concurrent flow with the hot air. The results indicated that, in order to film cool a given surface area with as little coolant flow as possible, it may be necessary to limit the flow of coolant introduced at a single axial position and to introduce it at several axial positions. The flow rate of inert coolant required to maintain liquid-film cooling over a given area of tube surface can be estimated when the gas-flow conditions are known by means of a generalized plot of the film-cooling data.

  2. Thrust chamber material technology program

    NASA Astrophysics Data System (ADS)

    Andrus, J. S.; Bordeau, R. G.

    1989-03-01

    This report covers work performed at Pratt & Whitney on development of copper-based materials for long-life, reusable, regeneratively cooled rocket engine thrust chambers. The program approached the goal of enhanced cyclic life through the application of rapid solidification to alloy development, to introduce fine dispersions to strengthen and stabilize the alloys at elevated temperatures. After screening of alloy systems, copper-based alloys containing Cr, Co, Hf, Ag, Ti, and Zr were processed by rapid-solidification atomization in bulk quantities. Those bulk alloys showing the most promise were characterized by tensile testing, thermal conductivity testing, and elevated-temperature, low-cycle fatigue (LFC) testing. Characterization indicated that Cu- 1.1 percent Hf exhibited the greatest potential as an improved-life thrust chamber material, exhibiting LCF life about four times that of NASA-Z. Other alloys (Cu- 0.6 percent Zr, and Cu- 0.6 percent Zr- 1.0 percent Cr) exhibited promise for use in this application, but needed more development work to balance properties.

  3. Thrust chamber material technology program

    NASA Technical Reports Server (NTRS)

    Andrus, J. S.; Bordeau, R. G.

    1989-01-01

    This report covers work performed at Pratt & Whitney on development of copper-based materials for long-life, reusable, regeneratively cooled rocket engine thrust chambers. The program approached the goal of enhanced cyclic life through the application of rapid solidification to alloy development, to introduce fine dispersions to strengthen and stabilize the alloys at elevated temperatures. After screening of alloy systems, copper-based alloys containing Cr, Co, Hf, Ag, Ti, and Zr were processed by rapid-solidification atomization in bulk quantities. Those bulk alloys showing the most promise were characterized by tensile testing, thermal conductivity testing, and elevated-temperature, low-cycle fatigue (LFC) testing. Characterization indicated that Cu- 1.1 percent Hf exhibited the greatest potential as an improved-life thrust chamber material, exhibiting LCF life about four times that of NASA-Z. Other alloys (Cu- 0.6 percent Zr, and Cu- 0.6 percent Zr- 1.0 percent Cr) exhibited promise for use in this application, but needed more development work to balance properties.

  4. Bulk-Flow Analysis of Hybrid Thrust Bearings for Advanced Cryogenic Turbopumps

    NASA Technical Reports Server (NTRS)

    SanAndres, Luis

    1998-01-01

    on a Windows 95/NT personal computer. The program, help files and examples are licensed by Texas A&M University Technology License Office. The study of the static and dynamic performance of two hydrostatic/hydrodynamic bearings demonstrates the importance of centrifugal and advection fluid inertia effects for operation at high rotational speeds. The first example considers a conceptual hydrostatic thrust bearing for an advanced liquid hydrogen turbopump operating at 170,000 rpm. The large axial stiffness and damping coefficients of the bearing should provide accurate control and axial positioning of the turbopump and also allow for unshrouded impellers, therefore increasing the overall pump efficiency. The second bearing uses a refrigerant R134a, and its application in oil-free air conditioning compressors is of great technological importance and commercial value. The computed predictions reveal that the LH2 bearing load capacity and flow rate increase with the recess pressure (i.e. increasing orifice diameters). The bearing axial stiffness has a maximum for a recess pressure rati of approx. 0.55. while the axial damping coefficient decreases as the recess pressure ratio increases. The computer results from three flow models are compared. These models are a) inertialess, b) fluid inertia at recess edges only, and c) full fluid inertia at both recess edges and film lands. The full inertia model shows the lowest flow rates, axial load capacity and stiffness coefficient but on the other hand renders the largest damping coefficients and inertia coefficients. The most important findings are related to the reduction of the outflow through the inner radius and the appearance of subambient pressures. The performance of the refrigerant hybrid thrust bearing is evaluated at two operating speeds and pressure drops. The computed results are presented in dimensionless form to evidence consistent trends in the bearing performance characteristics. As the applied axial load

  5. Effects of air annealing on CdS quantum dots thin film grown at room temperature by CBD technique intended for photosensor applications

    SciTech Connect

    Shaikh, Shaheed U.; Desale, Dipalee J.; Siddiqui, Farha Y.; Ghosh, Arindam; Birajadar, Ravikiran B.; Ghule, Anil V.; Sharma, Ramphal

    2012-11-15

    Graphical abstract: The effect of different intensities (40, 60 100 and 200 W) of light on CdS quantum dots thin film annealed at 350 °C indicating enhancement in (a) photo-current and (b) photosensitivity. Highlights: ► The preparation of CdS nanodot thin film at room temperature by M-CBD technique. ► Study of air annealing on prepared CdS nanodots thin film. ► The optimized annealing temperature for CdS nanodot thin film is 350 °C. ► Modified CdS thin films can be used in photosensor application. -- Abstract: CdS quantum dots thin-films have been deposited onto the glass substrate at room temperature using modified chemical bath deposition technique. The prepared thin films were further annealed in air atmosphere at 150, 250 and 350 °C for 1 h and subsequently characterized by scanning electron microscopy, ultraviolet–visible spectroscopy, electrical resistivity and I–V system. The modifications observed in morphology and opto-electrical properties of the thin films are presented.

  6. Solar electric propulsion thrust beam interactive effects

    NASA Technical Reports Server (NTRS)

    Sellen, J. M., Jr.; Fitzgerald, D. J.

    1975-01-01

    Interactive effects between ion engine thrust beams and an SEP spacecraft and its science payload have been examined. AC electric contamination from thrust beam potential fluctuations of both 'common mode' and 'point-to-point' forms has been evaluated. Quenching of point-to-point E-fields by both thrust ion and charge exchange ion plasmas is expected. Reduction methods for AC electric contamination from common mode thrust beam potential fluctuations have been developed. Charged particle contamination of ambient space and plasma wave contamination may result from density magnitude and spatial extent of charge exchange plasma plumes. Reduction methods for cone of directions of high angle charge exchange ions have been examined.

  7. Dielectric Barrier Discharge (DBD) Plasma Actuators Thrust-Measurement Methodology Incorporating New Anti-Thrust Hypothesis

    NASA Technical Reports Server (NTRS)

    Ashpis, David E.; Laun, Matthew C.

    2014-01-01

    We discuss thrust measurements of Dielectric Barrier Discharge (DBD) plasma actuators devices used for aerodynamic active flow control. After a review of our experience with conventional thrust measurement and significant non-repeatability of the results, we devised a suspended actuator test setup, and now present a methodology of thrust measurements with decreased uncertainty. The methodology consists of frequency scans at constant voltages. The procedure consists of increasing the frequency in a step-wise fashion from several Hz to the maximum frequency of several kHz, followed by frequency decrease back down to the start frequency of several Hz. This sequence is performed first at the highest voltage of interest, then repeated at lower voltages. The data in the descending frequency direction is more consistent and selected for reporting. Sample results show strong dependence of thrust on humidity which also affects the consistency and fluctuations of the measurements. We also observed negative values of thrust or "anti-thrust", at low frequencies between 4 Hz and up to 64 Hz. The anti-thrust is proportional to the mean-squared voltage and is frequency independent. Departures from the parabolic anti-thrust curve are correlated with appearance of visible plasma discharges. We propose the anti-thrust hypothesis. It states that the measured thrust is a sum of plasma thrust and anti-thrust, and assumes that the anti-thrust exists at all frequencies and voltages. The anti-thrust depends on actuator geometry and materials and on the test installation. It enables the separation of the plasma thrust from the measured total thrust. This approach enables more meaningful comparisons between actuators at different installations and laboratories. The dependence on test installation was validated by surrounding the actuator with a large diameter, grounded, metal sleeve.

  8. The Beaufort Sea fold-and-thrust belt, northwestern Canada: Implications for thrust-belt evolution

    SciTech Connect

    Root, K.G. )

    1991-06-01

    The northeasternmost segment of the Cordilleran thrust belt of western North American underlies the Beaufort Sea continental margin. Folds and associated northesat-directed thrusts in this region formed synchronously with Tertiary sedimentation. As a result, the times of fold development can be determined from reflection seismic data by analyzing lateral thickness changes in stratigraphic sequences of known ages, and onlap and truncation relationships at unconformities. Thrust faulting occurred throughout the late Paleocene-Pliocene. The abundant temporal data indicate the deformational seuqence was significantly differet from the simple, steplike, foreland-propagating model formulated in other less well-dated thrust belts. Many thrusts were active simultaneously, especially during the late Eocnee, when the region of active thrusting had an across-strike width of greater than 200 km. This observation calls into question the popular concept that only one thrust moves at a time as a thrust belt develops. The thrust belt propagated along, as well as across, strike. During the late Paleocene-middle Eocene, the area of active thrusting was bounded on the southeast by poorly imaged zones of right-lateral strike-slip faults that apparently are the northern offshore continuation of the Rapid fault array. The change in the age of thrusting along strike results in no obvious geometrical anomalies and could not be deduced without timing information. This has an important implication: temporal data cannot necessarily be projected along strike in a thrust belt.

  9. Lightweight Chambers for Thrust Assemblies

    NASA Technical Reports Server (NTRS)

    Elam, Sandra K.; Lee, Jonathan; Holmes, Richard; Zimmerman, Frank; Effinger, Mike; Turner, James E. (Technical Monitor)

    2001-01-01

    The Marshall Space Flight Center (MSFC) of the National Aeronautics and Space Administration (NASA) has successfully applied new materials and fabrication techniques to create actively cooled thrust chambers that operate 200-400 degrees hotter and weigh 50% lighter than conventional designs. In some vehicles, thrust assemblies account for as much as 20% of the engine weight. So, reducing the weight of these components and increasing their operating range will benefit many engines and vehicle designs, including Reusable Launch Vehicle (RLV) concepts. Obviously, copper and steel alloys have been used successfully for many years in the chamber components of thrust assemblies. Yet, by replacing the steel alloys with Polymer Matrix Composite (PMC) and/or Metal Matrix Composite (MMC) materials, design weights can be drastically reduced. In addition, replacing the traditional copper alloys with a Ceramic Matrix Composite (CMC) or an advanced copper alloy (Cu-8Cr-4Nb, also known as GRCop-84) significantly increases allowable operating temperatures. Several small MMC and PMC demonstration chambers have recently been fabricated with promising results. Each of these designs included GRCop-84 for the cooled chamber liner. These units successfully verified that designs over 50% lighter are feasible. New fabrication processes, including advanced casting technology and a low cost vacuum plasma spray (VPS) process, were also demonstrated with these units. Hot-fire testing at MSFC is currently being conducted on the chambers to verify increased operating temperatures available with the GRCop-84 liner. Unique CMC chamber liners were also successfully fabricated and prepared for hot-fire testing. Yet, early results indicate these CMC liners need significantly more development in order to use them in required chamber designs. Based on the successful efforts with the MMC and PMC concepts, two full size "lightweight" chambers are currently being designed and fabricated for hot

  10. Rocket Engine Thrust Chamber Assembly

    NASA Technical Reports Server (NTRS)

    Cornelius, Charles S. (Inventor); Counts, Richard H. (Inventor); Myers, W. Neill (Inventor); Lackey, Jeffrey D. (Inventor); Peters, Warren (Inventor); Shadoan, Michael D. (Inventor); Sparks, David L. (Inventor); Lawrence, Timothy W. (Inventor)

    2001-01-01

    A thrust chamber assembly for liquid fueled rocket engines and the method of making it wherein a two-piece mandrel wrapped with a silica tape saturated with a phenolic resin, the tape extending along the mandrel and covering the combustion chamber portion of the mandrel to the throat portion. The phenolic in the tape is cured and the end of the wrap is machined. The remainder of the mandrel is wrapped with a third silica tape. The resin in the third tape is cured and the assembly is machined. The entire assembly is then wrapped with a tow of graphite fibers wetted with an epoxy resin and, after the epoxy resin is cured, the graphite is machined to final dimensions.

  11. High power thrust vector actuation

    NASA Astrophysics Data System (ADS)

    Kittock, M. J.

    1993-06-01

    Modern missile programs are frequently favoring electro-mechanical (EM) thrust vector actuation (TVA) over hydraulic for a variety of reasons. However, actuation system performance requirements are not relaxed for EM systems. Thus the development of EM systems with greater power output is required. The configuration of EM actuator studied consists of a DC brushless motor driving a spur gear train, which drives a ballscrew that converts rotary motion to rectilinear motion. This design produces an actuator with high levels of performance in a compact mechanical package. Design for manufacturability and assembly (DFMA) was part of the design process, resulting in an actuator that can be assembled easily and will operate reliably. This paper will discuss the mechanical details of the resultant actuator and report test results on a prototype derivative.

  12. Low thrust rocket test facility

    NASA Technical Reports Server (NTRS)

    Arrington, Lynn A.; Schneider, Steven J.

    1990-01-01

    A low thrust chemical rocket test facility has recently become operational at the NASA-Lewis. The new facility is used to conduct both long duration and performance tests at altitude over a thruster's operating envelope using hydrogen and oxygen gas for propellants. The facility provides experimental support for a broad range of objectives, including fundamental modeling of fluids and combustion phenomena, the evaluation of thruster components, and life testing of full rocket designs. The major mechanical and electrical systems are described along with aspects of the various optical diagnostics available in the test cell. The electrical and mechanical systems are designed for low down time between tests and low staffing requirements for test operations. Initial results are also presented which illustrate the various capabilities of the cell.

  13. Another Look at Rocket Thrust

    NASA Astrophysics Data System (ADS)

    Hester, Brooke; Burris, Jennifer

    2012-12-01

    Rocket propulsion is often introduced as an example of Newton's third law. The rocket exerts a force on the exhaust gas being ejected; the gas exerts an equal and opposite force—the thrust—on the rocket.1,2 Equivalently, in the absence of a net external force, the total momentum of the system, rocket plus ejected gas, remains constant. The law of conservation of momentum is generally used in textbooks3,4 and elsewhere5 in deriving the rocket thrust equation. In this paper we take the somewhat different approach of explicitly applying Newton's second law to the rocket. This method provides a good opportunity to show the importance of choosing carefully the system to which Newton's second law is applied.

  14. Formation of oxygen vacancies and Ti(3+) state in TiO2 thin film and enhanced optical properties by air plasma treatment.

    PubMed

    Bharti, Bandna; Kumar, Santosh; Lee, Heung-No; Kumar, Rajesh

    2016-01-01

    This is the first time we report that simply air plasma treatment can also enhances the optical absorbance and absorption region of titanium oxide (TiO2) films, while keeping them transparent. TiO2 thin films having moderate doping of Fe and Co exhibit significant enhancement in the aforementioned optical properties upon air plasma treatment. The moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers. Variation in surface species viz. Ti(3+), Ti(4+), O(2-), oxygen vacancies, OH group and optical properties was studied using X-ray photon spectroscopy (XPS) and UV-Vis spectroscopy. The air plasma treatment caused enhanced optical absorbance and optical absorption region as revealed by the formation of Ti(3+) and oxygen vacancies in the band gap of TiO2 films. The samples were treated in plasma with varying treatment time from 0 to 60 seconds. With the increasing treatment time, Ti(3+) and oxygen vacancies increased in the Fe and Co doped TiO2 films leading to increased absorbance; however, the increase in optical absorption region/red shift (from 3.22 to 3.00 eV) was observed in Fe doped TiO2 films, on the contrary Co doped TiO2 films exhibited blue shift (from 3.36 to 3.62 eV) due to Burstein Moss shift. PMID:27572095

  15. Formation of oxygen vacancies and Ti3+ state in TiO2 thin film and enhanced optical properties by air plasma treatment

    NASA Astrophysics Data System (ADS)

    Bharti, Bandna; Kumar, Santosh; Lee, Heung-No; Kumar, Rajesh

    2016-08-01

    This is the first time we report that simply air plasma treatment can also enhances the optical absorbance and absorption region of titanium oxide (TiO2) films, while keeping them transparent. TiO2 thin films having moderate doping of Fe and Co exhibit significant enhancement in the aforementioned optical properties upon air plasma treatment. The moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers. Variation in surface species viz. Ti3+, Ti4+, O2‑, oxygen vacancies, OH group and optical properties was studied using X-ray photon spectroscopy (XPS) and UV-Vis spectroscopy. The air plasma treatment caused enhanced optical absorbance and optical absorption region as revealed by the formation of Ti3+ and oxygen vacancies in the band gap of TiO2 films. The samples were treated in plasma with varying treatment time from 0 to 60 seconds. With the increasing treatment time, Ti3+ and oxygen vacancies increased in the Fe and Co doped TiO2 films leading to increased absorbance; however, the increase in optical absorption region/red shift (from 3.22 to 3.00 eV) was observed in Fe doped TiO2 films, on the contrary Co doped TiO2 films exhibited blue shift (from 3.36 to 3.62 eV) due to Burstein Moss shift.

  16. Formation of oxygen vacancies and Ti3+ state in TiO2 thin film and enhanced optical properties by air plasma treatment

    PubMed Central

    Bharti, Bandna; Kumar, Santosh; Lee, Heung-No; Kumar, Rajesh

    2016-01-01

    This is the first time we report that simply air plasma treatment can also enhances the optical absorbance and absorption region of titanium oxide (TiO2) films, while keeping them transparent. TiO2 thin films having moderate doping of Fe and Co exhibit significant enhancement in the aforementioned optical properties upon air plasma treatment. The moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers. Variation in surface species viz. Ti3+, Ti4+, O2−, oxygen vacancies, OH group and optical properties was studied using X-ray photon spectroscopy (XPS) and UV-Vis spectroscopy. The air plasma treatment caused enhanced optical absorbance and optical absorption region as revealed by the formation of Ti3+ and oxygen vacancies in the band gap of TiO2 films. The samples were treated in plasma with varying treatment time from 0 to 60 seconds. With the increasing treatment time, Ti3+ and oxygen vacancies increased in the Fe and Co doped TiO2 films leading to increased absorbance; however, the increase in optical absorption region/red shift (from 3.22 to 3.00 eV) was observed in Fe doped TiO2 films, on the contrary Co doped TiO2 films exhibited blue shift (from 3.36 to 3.62 eV) due to Burstein Moss shift. PMID:27572095

  17. Formation of oxygen vacancies and Ti(3+) state in TiO2 thin film and enhanced optical properties by air plasma treatment.

    PubMed

    Bharti, Bandna; Kumar, Santosh; Lee, Heung-No; Kumar, Rajesh

    2016-08-30

    This is the first time we report that simply air plasma treatment can also enhances the optical absorbance and absorption region of titanium oxide (TiO2) films, while keeping them transparent. TiO2 thin films having moderate doping of Fe and Co exhibit significant enhancement in the aforementioned optical properties upon air plasma treatment. The moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers. Variation in surface species viz. Ti(3+), Ti(4+), O(2-), oxygen vacancies, OH group and optical properties was studied using X-ray photon spectroscopy (XPS) and UV-Vis spectroscopy. The air plasma treatment caused enhanced optical absorbance and optical absorption region as revealed by the formation of Ti(3+) and oxygen vacancies in the band gap of TiO2 films. The samples were treated in plasma with varying treatment time from 0 to 60 seconds. With the increasing treatment time, Ti(3+) and oxygen vacancies increased in the Fe and Co doped TiO2 films leading to increased absorbance; however, the increase in optical absorption region/red shift (from 3.22 to 3.00 eV) was observed in Fe doped TiO2 films, on the contrary Co doped TiO2 films exhibited blue shift (from 3.36 to 3.62 eV) due to Burstein Moss shift.

  18. Urease and hexadecylamine-urease films at the air-water interface: an x-ray reflection and grazing incidence x-ray diffraction study.

    PubMed Central

    Gidalevitz, D; Huang, Z; Rice, S A

    1999-01-01

    We report the results of surface x-ray scattering measurements performed on urease and hexadecylamine-urease films at the air-aqueous solution interface. It is demonstrated that although hexadecylamine does not form a stable monolayer on the pure aqueous surface, it does self-assemble into a stable, well-organized structure when spread on top of a urease film at the air-water interface. It is also likely that protein and hexadecylamine domains coexist at the interface. PMID:10233095

  19. Photoinduced Directional Motions of Microparticles at Air-Liquid-Crystal Interfaces of Azobenzene-Doped Liquid-Crystal Films with Homeotropic or Homogeneous Alignment Structures

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takahiro; Yoshida, Masaru

    2012-10-01

    We investigated the effects of liquid-crystal (LC) alignments on photoinduced motions of microparticles at air-LC interfaces of azobenzene-doped LC films. In homeotropically aligned LC films, the lattice spacings of pseudo-hexagonal structures of microparticles site-selectively exhibited reversible expansion or contraction on alternating irradiation with ultraviolet and visible light. The particle motions were probably driven by photochemical deformation of LC surfaces. In homogeneously aligned films, alternating irradiation induced macroscopic convective flows followed by rapid gathering or dispersion of linear chains of microparticles. Particle motions were significantly influenced by LC alignments as well as the light wavelength.

  20. Changes in the electro-physical properties of MCT epitaxial films affected by a plasma volume discharge induced by an avalanche beam in atmospheric-pressure air

    NASA Astrophysics Data System (ADS)

    Grigoryev, D. V.; Voitsekhovskii, A. V.; Lozovoy, K. A.; Tarasenko, V. F.; Shulepov, M. A.

    2015-11-01

    In this paper the influence of the plasma volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of epitaxial films HgCdTe (MCT) films are discussed. The experimental data show that the action of pulses of nanosecond volume discharge in air at atmospheric pressure leads to changes in the electrophysical properties of MCT epitaxial films due to formation of a near-surface high- conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of MCT.

  1. Thrust bolting: roof bolt support apparatus

    DOEpatents

    Tadolini, Stephen C.; Dolinar, Dennis R.

    1992-01-01

    A method of installing a tensioned roof bolt in a borehole of a rock formation without the aid of a mechanical anchoring device or threaded tensioning threads by applying thrust to the bolt (19) as the bonding material (7') is curing to compress the strata (3) surrounding the borehole (1), and then relieving the thrust when the bonding material (7') has cured.

  2. Mu rhythm desynchronization by tongue thrust observation

    PubMed Central

    Sakihara, Kotoe; Inagaki, Masumi

    2015-01-01

    We aimed to investigate the mu rhythm in the sensorimotor area during tongue thrust observation and to obtain an answer to the question as to how subtle non-verbal orofacial movement observation activates the sensorimotor area. Ten healthy volunteers performed finger tap execution, tongue thrust execution, and tongue thrust observation. The electroencephalogram (EEG) was recorded from 128 electrodes placed on the scalp, and regions of interest were set at sensorimotor areas. The event-related desynchronization (ERD) and event-related synchronization (ERS) for the mu rhythm (8–13 Hz) and beta (13−25 Hz) bands were measured. Tongue thrust observation induced mu rhythm ERD, and the ERD was detected at the left hemisphere regardless whether the observed tongue thrust was toward the left or right. Mu rhythm ERD was also recorded during tongue thrust execution. However, temporal analysis revealed that the ERD associated with tongue thrust observation preceded that associated with execution by approximately 2 s. Tongue thrust observation induces mu rhythm ERD in sensorimotor cortex with left hemispheric dominance. PMID:26441599

  3. Measuring Model Rocket Engine Thrust Curves

    ERIC Educational Resources Information Center

    Penn, Kim; Slaton, William V.

    2010-01-01

    This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…

  4. Humidity-dependent compression-induced glass transition of the air-water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA).

    PubMed

    Kim, Hyun Chang; Lee, Hoyoung; Jung, Hyunjung; Choi, Yun Hwa; Meron, Mati; Lin, Binhua; Bang, Joona; Won, You-Yeon

    2015-07-28

    Constant rate compression isotherms of the air-water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA) show a distinct feature of an exponential increase in surface pressure in the high surface polymer concentration regime. We have previously demonstrated that this abrupt increase in surface pressure is linked to the glass transition of the polymer film, but the detailed mechanism of this process is not fully understood. In order to obtain a molecular-level understanding of this behavior, we performed extensive characterizations of the surface mechanical, structural and rheological properties of Langmuir PLGA films at the air-water interface, using combined experimental techniques including the Langmuir film balance, X-ray reflectivity and double-wall-ring interfacial rheometry methods. We observed that the mechanical and structural responses of the Langmuir PLGA films are significantly dependent on the rate of film compression; the glass transition was induced in the PLGA film only at fast compression rates. Surprisingly, we found that this deformation rate dependence is also dependent on the humidity of the environment. With water acting as a plasticizer for the PLGA material, the diffusion of water molecules through the PLGA film seems to be the key factor in the determination of the glass transformation properties and thus the mechanical response of the PLGA film against lateral compression. Based on our combined results, we hypothesize the following mechanism for the compression-induced glass transformation of the Langmuir PLGA film; (1) initially, a humidified/non-glassy PLGA film is formed in the full surface-coverage region (where the surface pressure shows a plateau) during compression; (2) further compression leads to the collapse of the PLGA chains and the formation of new surfaces on the air side of the film, and this newly formed top layer of the PLGA film is transiently glassy in character because the water evaporation rate

  5. Humidity-dependent compression-induced glass transition of the air-water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA).

    PubMed

    Kim, Hyun Chang; Lee, Hoyoung; Jung, Hyunjung; Choi, Yun Hwa; Meron, Mati; Lin, Binhua; Bang, Joona; Won, You-Yeon

    2015-07-28

    Constant rate compression isotherms of the air-water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA) show a distinct feature of an exponential increase in surface pressure in the high surface polymer concentration regime. We have previously demonstrated that this abrupt increase in surface pressure is linked to the glass transition of the polymer film, but the detailed mechanism of this process is not fully understood. In order to obtain a molecular-level understanding of this behavior, we performed extensive characterizations of the surface mechanical, structural and rheological properties of Langmuir PLGA films at the air-water interface, using combined experimental techniques including the Langmuir film balance, X-ray reflectivity and double-wall-ring interfacial rheometry methods. We observed that the mechanical and structural responses of the Langmuir PLGA films are significantly dependent on the rate of film compression; the glass transition was induced in the PLGA film only at fast compression rates. Surprisingly, we found that this deformation rate dependence is also dependent on the humidity of the environment. With water acting as a plasticizer for the PLGA material, the diffusion of water molecules through the PLGA film seems to be the key factor in the determination of the glass transformation properties and thus the mechanical response of the PLGA film against lateral compression. Based on our combined results, we hypothesize the following mechanism for the compression-induced glass transformation of the Langmuir PLGA film; (1) initially, a humidified/non-glassy PLGA film is formed in the full surface-coverage region (where the surface pressure shows a plateau) during compression; (2) further compression leads to the collapse of the PLGA chains and the formation of new surfaces on the air side of the film, and this newly formed top layer of the PLGA film is transiently glassy in character because the water evaporation rate

  6. Phases, line tension and pattern formation in molecularly thin films at the air-water interface

    NASA Astrophysics Data System (ADS)

    Mandal, Pritam

    A Langmuir film, which is a molecularly thin insoluble film on a liquid substrate, is one practical realization of a quasi-two dimensional matter. The major advantages of this system for the study of phase separation and phase co-existence are (a) it allows accurate control of the components and molecular area of the film and (b) it can be studied by various methods that require very flat films. Phase separation in molecularly thin films plays an important role in a range of systems from biomembranes to biosensors. For example, phase-separated lipid nano-domains in biomembranes are thought to play crucial roles in membrane function. I use Brewster Angel Microscopy (BAM) coupled with Fluorescence Microscopy (FM) and static Light Scattering Microscopy (LSM) to image phases and patterns within Langmuir films. The three microscopic techniques --- BAM, FM and LSM --- are complimentary to each other, providing distinct sets of information. They allow direct comparison with literature results in lipid systems. I have quantitatively validated the use of detailed hydrodynamic simulations to determine line tension in monolayers. Line tension decreases as temperature rises. This decrease gives us information on the entropy associated with the line, and thus about line structure. I carefully consider the thermodynamics of line energy and entropy to make this connection. In the longer run, LSM will be exploited to give us further information about line structure. I have also extended the technique by testing it on domains within the curved surface of a bilayer vesicle. I also note that in the same way that the presence of surface-active agents, known as surfactants, affects surface energy, the addiction of line active agents alters the inter-phase line energy. Thus my results set to stage to systematically study the influence of line active agents ---'linactants' --- on the inter-phase line energy. Hierarchal self-assembled chiral patterns were observed as a function of

  7. Oxygen/Alcohol Dual Thrust RCS Engines

    NASA Technical Reports Server (NTRS)

    Angstadt, Tara; Hurlbert, Eric

    1999-01-01

    A non-toxic dual thrust RCS engine offers significant operational, safety, and performance advantages to the space shuttle and the next generation RLVs. In this concept, a single engine produces two thrust levels of 25 and 870 lbf. The low thrust level is provided by the spark torch igniter, which, with the addition of 2 extra valves, can also be made to function as a vernier. A dual thrust RCS engine allows 38 verniers to be packaged more efficiently on a vehicle. These 38 vemiers improve translation and reduce cross coupling, thereby providing more pure roll, pitch, and yaw maneuvers of the vehicle. Compared to the 6 vemiers currently on the shuttle, the 38 dual thrust engines would be 25 to 40% more efficient for the same maneuvers and attitude control. The vernier thrust level also reduces plume impingement and contamination concerns. Redundancy is also improved, thereby improving mission success reliability. Oxygen and ethanol are benign propellants which do not create explosive reaction products or contamination, as compared to hypergolic propellants. These characteristics make dual-thrust engines simpler to implement on a non-toxic reaction control system. Tests at WSTF in August 1999 demonstrated a dual-thrust concept that is successful with oxygen and ethanol. Over a variety of inlet pressures and mixture ratios at 22:1 area ratio, the engine produced between 230 and 297 sec Isp, and thrust levels from 8 lbf. to 50 lbf. This paper describes the benefits of dual-thrust engines and the recent results from tests at WSTF.

  8. Note: Radial-thrust combo metal mesh foil bearing for microturbomachinery.

    PubMed

    Park, Cheol Hoon; Choi, Sang Kyu; Hong, Doo Euy; Yoon, Tae Gwang; Lee, Sung Hwi

    2013-10-01

    This Note proposes a novel radial-thrust combo metal mesh foil bearing (MMFB). Although MMFBs have advantages such as higher stiffness and damping over conventional air foil bearings, studies related to MMFBs have been limited to radial MMFBs. The novel combo MMFB is composed of a radial top foil, thrust top foils, and a ring-shaped metal mesh damper--fabricated by compressing a copper wire mesh--with metal mesh thrust pads for the thrust bearing at both side faces. In this study, the combo MMFB was fabricated in half-split type to support the rotor for a micro gas turbine generator. The manufacture and assembly process for the half-split-type combo MMFB is presented. In addition, to verify the proposed combo MMFB, motoring test results up to 250,000 rpm and axial displacements as a function of rotational speed are presented. PMID:24182175

  9. Note: Radial-thrust combo metal mesh foil bearing for microturbomachinery

    NASA Astrophysics Data System (ADS)

    Park, Cheol Hoon; Choi, Sang Kyu; Hong, Doo Euy; Yoon, Tae Gwang; Lee, Sung Hwi

    2013-10-01

    This Note proposes a novel radial-thrust combo metal mesh foil bearing (MMFB). Although MMFBs have advantages such as higher stiffness and damping over conventional air foil bearings, studies related to MMFBs have been limited to radial MMFBs. The novel combo MMFB is composed of a radial top foil, thrust top foils, and a ring-shaped metal mesh damper—fabricated by compressing a copper wire mesh—with metal mesh thrust pads for the thrust bearing at both side faces. In this study, the combo MMFB was fabricated in half-split type to support the rotor for a micro gas turbine generator. The manufacture and assembly process for the half-split-type combo MMFB is presented. In addition, to verify the proposed combo MMFB, motoring test results up to 250 000 rpm and axial displacements as a function of rotational speed are presented.

  10. Interaction of hot swirling air and liquid film flow in airblast atomizers

    NASA Astrophysics Data System (ADS)

    Baumann, Wolfgang W.; Bendisch, Holger; Eickhoff, Heinrich; Thiele, Frank

    The flowfield in an airblast atomizer of the prefilming type is studied numerically. Special attention is drawn to the flow near the liquid film surface, which is calculated using a boundary-layer method. Thereby near-wall effects (e.g., evaporation) are exactly accounted for. The main nozzle flow is calculated using the Navier-Stokes equations. Both systems are linked by the boundary conditions. The results for an airblast atomizer with adjacent combustion chamber show significant differences between coupled and uncoupled calculations. It is shown that the detailed modeling of the film and the coupled calculation, which accounts exactly for boundary-layer effects including evaporation, is essential for accurate simulations.

  11. Fabrication of air-stable n-type carbon nanotube thin-film transistors on flexible substrates using bilayer dielectrics

    NASA Astrophysics Data System (ADS)

    Li, Guanhong; Li, Qunqing; Jin, Yuanhao; Zhao, Yudan; Xiao, Xiaoyang; Jiang, Kaili; Wang, Jiaping; Fan, Shoushan

    2015-10-01

    Single-walled carbon nanotube (SWNT) thin-film transistors hold great potential for flexible electronics. However, fabrication of air-stable n-type devices by methods compatible with standard photolithography on flexible substrates is challenging. Here, we demonstrated that by using a bilayer dielectric structure of MgO and atomic layer deposited (ALD) Al2O3 or HfO2, air-stable n-type devices can be obtained. The mechanism for conduction type conversion was elucidated and attributed to the hole depletion in SWNT, the decrease of the trap state density by MgO assimilating adsorbed water molecules in the vicinity of SWNT, and the energy band bending because of the positive fixed charges in the ALD layer. The key advantage of the method is the relatively low temperature (120 or 90 °C) required here for the ALD process because we need not employ this step to totally remove the absorbates on the SWNTs. This advantage facilitates the integration of both p-type and n-type transistors through a simple lift off process and compact CMOS inverters were demonstrated. We also demonstrated that the doping of SWNTs in the channel plays a more important role than the Schottky barriers at the metal contacts in carbon nanotube thin-film transistors, unlike the situation in individual SWNT-based transistors.Single-walled carbon nanotube (SWNT) thin-film transistors hold great potential for flexible electronics. However, fabrication of air-stable n-type devices by methods compatible with standard photolithography on flexible substrates is challenging. Here, we demonstrated that by using a bilayer dielectric structure of MgO and atomic layer deposited (ALD) Al2O3 or HfO2, air-stable n-type devices can be obtained. The mechanism for conduction type conversion was elucidated and attributed to the hole depletion in SWNT, the decrease of the trap state density by MgO assimilating adsorbed water molecules in the vicinity of SWNT, and the energy band bending because of the positive fixed

  12. Air stable n-doping of WSe{sub 2} by silicon nitride thin films with tunable fixed charge density

    SciTech Connect

    Chen, Kevin; Kiriya, Daisuke; Hettick, Mark; Tosun, Mahmut; Ha, Tae-Jun; Madhvapathy, Surabhi Rao; Desai, Sujay; Sachid, Angada; Javey, Ali

    2014-09-01

    Stable n-doping of WSe{sub 2} using thin films of SiN{sub x} deposited on the surface via plasma-enhanced chemical vapor deposition is presented. Positive fixed charge centers inside SiN{sub x} act to dope WSe{sub 2} thin flakes n-type via field-induced effect. The electron concentration in WSe{sub 2} can be well controlled up to the degenerate limit by simply adjusting the stoichiometry of the SiN{sub x} through deposition process parameters. For the high doping limit, the Schottky barrier width at the metal/WSe{sub 2} junction is significantly thinned, allowing for efficient electron injection via tunneling. Using this doping scheme, we demonstrate air-stable WSe{sub 2} n-MOSFETs with a mobility of ∼70 cm{sup 2}/V s.

  13. Gold-on-Polymer-Based Sensing Films for Detection of Organic and Inorganic Analytes in the Air

    NASA Technical Reports Server (NTRS)

    Manatt, Kenneth; Homer, Margie; Ryan, Margaret; Kisor, Adam; Shevade, Abhijit; Jewell, April; Zhou, Hanying

    2008-01-01

    A document discusses gold-on-polymer as one of the novel sensor types developed for part of the sensor development task. Standard polymer-carbon composite sensors used in the JPL Electronic Nose (ENose) have been modified by evaporating 15 nm of metallic gold on the surface. These sensors have been shown to respond to alcohols, aromatics, ammonia, sulfur dioxide, and elemental mercury in the parts-per-million and parts-per-billion concentration ranges in humidified air. The results have shown good sensitivity of these films operating under mild conditions (operating temperatures 23-28 C and regeneration temperature up to 40 C). This unique sensor combines the diversity of polymer sensors for chemical sensing with their response to a wide variety of analytes with the specificity of a gold sensor that shows strong reaction/binding with selected analyte types, such as mercury or sulfur.

  14. Balancing soft elasticity and low surface polarity in films of charged BSA capsules at air/fluid interface.

    PubMed

    D, Madhumitha; Jaganathan, Maheshkumar; Dhathathreyan, Aruna; Miller, Reinhard

    2016-10-01

    Interaction between charged BSA colloids and the buffer at air/fluid interface has been studied using spread films of the capsules of the protein prepared at pH 4.5 and 7.5 (below and above the pI of BSA). Surface pressure-surface concentration plots, interfacial dilational rheology and Quartz crystal microbalance with dissipation have been used to characterize the films. The study shows that below the pI of the protein, the positively charged colloids entrain more water on the surface which leads to partial neutralization of the charges. Results suggest that the charged capsules are elastic due to the strongly adsorbed protein layers that restrict deformation and any small shape fluctuations is likely due to the distortion of the viscoelastic surface layer at pH=4.5. Capsules of BSA behave as 'soft elastic membrane' with interfacial properties lying between that of an elastic membrane and a slightly soluble diffuse capsule with low interfacial tension. Such elastic capsules would find applications in drug delivery and food colloids.

  15. Study on structural, morphological and thermal properties of surface modified polyvinylchloride (PVC) film under air, argon and oxygen discharge plasma

    NASA Astrophysics Data System (ADS)

    Suganya, Arjunan; Shanmugavelayutham, Gurusamy; Serra Rodríguez, Carmen

    2016-09-01

    The effect of air, argon, oxygen DC glow discharge plasma on the polyvinylchloride (PVC) film synthesized by solution casting technique, were evaluated via changes in physio-chemical properties such as structural, morphological, crystalline, thermal properties. The PVC film was plasma treated as a function of exposure time and different plasma forming gases, while other operating parameters such as power and pressure remained constant at 100 W and 2 Pa respectively. The plasma treated PVC were characterized by static contact angle, ATR-FTIR, XPS, AFM and T-peel analysis. It was found that various gaseous plasma treatments have improved the polar components, surface roughness on the surface of PVC which was confirmed by XPS, AFM, resulting in highly enhanced wettability and adhesion. X-ray diffraction study showed that plasma treatment does not persuade considerable change, even though it vaguely induces the crystallinity. The thermal properties of plasma treated PVC were evaluated by Differential Scanning Calorimetry and it was observed that O2 plasma treatment gives higher glass transition temperature of 87.21 °C compared with the untreated one. The glass transition temperature slightly increased for Oxygen plasma treated material due to the presence of higher concentration of the polar functional groups on the PVC surface due to strong intramolecular bonding.

  16. Tailoring indium oxide nanocrystal synthesis conditions for air-stable high-performance solution-processed thin-film transistors.

    PubMed

    Swisher, Sarah L; Volkman, Steven K; Subramanian, Vivek

    2015-05-20

    Semiconducting metal oxides (ZnO, SnO2, In2O3, and combinations thereof) are a uniquely interesting family of materials because of their high carrier mobilities in the amorphous and generally disordered states, and solution-processed routes to these materials are of particular interest to the printed electronics community. Colloidal nanocrystal routes to these materials are particularly interesting, because nanocrystals may be formulated with tunable surface properties into stable inks, and printed to form devices in an additive manner. We report our investigation of an In2O3 nanocrystal synthesis for high-performance solution-deposited semiconductor layers for thin-film transistors (TFTs). We studied the effects of various synthesis parameters on the nanocrystals themselves, and how those changes ultimately impacted the performance of TFTs. Using a sintered film of solution-deposited In2O3 nanocrystals as the TFT channel material, we fabricated devices that exhibit field effect mobility of 10 cm(2)/(V s) and an on/off current ratio greater than 1 × 10(6). These results outperform previous air-stable nanocrystal TFTs, and demonstrate the suitability of colloidal nanocrystal inks for high-performance printed electronics.

  17. Influence of pulsed nanosecond volume discharge in atmospheric-pressure air on the electrical characteristics of MCT epitaxial films

    NASA Astrophysics Data System (ADS)

    Grigoryev, Denis V.; Voitsekhovskii, Alexandr V.; Lozovoy, Kirill A.; Nesmelov, Sergey N.; Dzyadukh, Stanislav M.; Tarasenko, Viktor F.; Shulepov, Michail A.; Dvoretskii, Sergei A.

    2015-12-01

    The purpose of this paper was investigating the effect of volume nanosecond discharge in air at atmospheric pressure on the electro-physical properties of the HgCdTe (MCT) epitaxial films grown by molecular beam epitaxy. Hall measurements of electro-physical parameters of MCT samples after irradiation have shown that there is a layer of epitaxial films exhibiting n-type conductivity that is formed in the near-surface area. After more than 600 pulses of influence parameters and thickness of the resulting n-layer is such that the measured field dependence of Hall coefficient corresponds to the material of n-type conductivity. Also it is shown that the impact of the discharge leads to significant changes in electro-physical characteristics of MIS structures. This fact is demonstrated by increase in density of positive fixed charge, change in the hysteresis type of the capacitance-voltage characteristic, an increase in density of surface states. The preliminary results show that it is possible to use such actions in the development of technologies of the controlled change in the properties of MCT.

  18. Tailoring indium oxide nanocrystal synthesis conditions for air-stable high-performance solution-processed thin-film transistors.

    PubMed

    Swisher, Sarah L; Volkman, Steven K; Subramanian, Vivek

    2015-05-20

    Semiconducting metal oxides (ZnO, SnO2, In2O3, and combinations thereof) are a uniquely interesting family of materials because of their high carrier mobilities in the amorphous and generally disordered states, and solution-processed routes to these materials are of particular interest to the printed electronics community. Colloidal nanocrystal routes to these materials are particularly interesting, because nanocrystals may be formulated with tunable surface properties into stable inks, and printed to form devices in an additive manner. We report our investigation of an In2O3 nanocrystal synthesis for high-performance solution-deposited semiconductor layers for thin-film transistors (TFTs). We studied the effects of various synthesis parameters on the nanocrystals themselves, and how those changes ultimately impacted the performance of TFTs. Using a sintered film of solution-deposited In2O3 nanocrystals as the TFT channel material, we fabricated devices that exhibit field effect mobility of 10 cm(2)/(V s) and an on/off current ratio greater than 1 × 10(6). These results outperform previous air-stable nanocrystal TFTs, and demonstrate the suitability of colloidal nanocrystal inks for high-performance printed electronics. PMID:25915094

  19. Highly Conductive, Air-Stable Silver Nanowire@Iongel Composite Films toward Flexible Transparent Electrodes.

    PubMed

    Xiong, Weiwei; Liu, Hongliang; Chen, Yongzhen; Zheng, Meiling; Zhao, Yuanyuan; Kong, Xiangbin; Wang, Ying; Zhang, Xiqi; Kong, Xiangyu; Wang, Pengfei; Jiang, Lei

    2016-09-01

    A new type of flexible transparent electrode is designed, by employing wettability-induced selective electroless-welding of silver nanowire (AgNW) networks, together with a thin conductive iongel as the protective layer. The obtained electrode exhibits high optical transmittance, and excellent air-stability without sacrificing conductivity. PMID:27296551

  20. Collar nut and thrust ring

    DOEpatents

    Lowery, Guy B.

    1991-01-01

    A collar nut comprises a hollow cylinder having fine interior threads at one end for threadably engaging a pump mechanical seal assembly and an inwardly depending flange at the other end. The flange has an enlarged portion with a groove for receiving an O-ring for sealing against the intrusion of pumpage from the exterior. The enlarged portion engages a thrust ring about the pump shaft for crushing a hard O-ring, such as a graphite O-ring. The hard O-ring seals the interior of the mechanical seal assembly and pump housing against the loss of lubricants or leakage of pumpage. The fine threads of the hollow cylinder provide the mechanical advantage for crushing the hard O-ring evenly and easily with a hand tool from the side of the collar nut rather than by tightening a plurality of bolts from the end and streamlines the exterior surface of the mechanical seal. The collar nut avoids the spatial requirements of bolt heads at the end of a seal and associated bolt head turbulence.

  1. Rocket Engine Thrust Chamber Assembly

    NASA Technical Reports Server (NTRS)

    Cornelius, Charles S. (Inventor); Counts, Richard H. (Inventor); Myers, W. Neill (Inventor); Lackey, Jeffrey D. (Inventor); Peters, Warren (Inventor); Shadoan, Michael (Inventor); Sparks, David L. (Inventor); Lawrence, Timothy W. (Inventor)

    2001-01-01

    A thrust chamber assembly for liquid fueled rocket engines and the method of making it wherein a two-piece mandrel having the configuration of an assembly having a combustion chamber portion connected to a nozzle portion through a throat portion is wrapped with a silica tape saturated with a phenolic resin, the tape extending along the mandrel and covering the combustion chamber portion of the mandrel to the throat portion. The width of the tape is positioned at an angle of 30 to 50 deg. to the axis of the mandrel such that one edge of the tape contacts the mandrel while the other edge is spaced from the mandrel. The phenolic in the tape is cured and the end of the wrap is machined to provide a frusto-conical surface extending at an angle of 15 to 30 deg. with respect to the axis of the mandrel for starting a second wrap on the mandrel to cover the throat portion. The remainder of the mandrel is wrapped with a third silica tape having its width positioned at a angle of 5 to 20 deg. from the axis of the mandrel. The resin in the third tape is cured and the assembly is machined to provide a smooth outer surface. The entire assembly is then wrapped with a tow of graphite fibers wetted with an epoxy resin and, after the epoxy resin is cured, the graphite is machined to final dimensions.

  2. A method to form semiconductor quantum dot (QD) thin films by igniting a flame at air-liquid interface: CdS and WO3.

    PubMed

    Jadhav, Aarti H; Patil, Sagar H; Sathaye, Shivaram D; Patil, Kashinath R

    2015-02-01

    We reveal an easy, inexpensive, efficient one stepflame synthesis of semiconductor/metal oxide thin films at air-liquid interface, subsequently, transferred on suitable substrate. The method has been illustrated by the formation of CdS and WO3 QDs thin films. The features of the present method are (1) Growth of thin films consisting of0.5-2.0nm sized Quantum Dots (QDs)/(ultra-small nanoparticles) in a short time, at the air-liquid interface which can be suitably transferred by a well-known Blodgett technique to an appropriate substrate, (2) The method is suitable to apply layer by layer (LbL) technique to increase the film thickness as well as forming various compositions as revealed by AFM measurements. The films are characterized for their structure (SAED), morphology (TEM), optical properties (UV-Vis.) and photoluminescence (PL). Possible mechanism of formation of QDs thin film and effect of capping in case of CdS QDs is discussed. PMID:25463183

  3. A method to form semiconductor quantum dot (QD) thin films by igniting a flame at air-liquid interface: CdS and WO3.

    PubMed

    Jadhav, Aarti H; Patil, Sagar H; Sathaye, Shivaram D; Patil, Kashinath R

    2015-02-01

    We reveal an easy, inexpensive, efficient one stepflame synthesis of semiconductor/metal oxide thin films at air-liquid interface, subsequently, transferred on suitable substrate. The method has been illustrated by the formation of CdS and WO3 QDs thin films. The features of the present method are (1) Growth of thin films consisting of0.5-2.0nm sized Quantum Dots (QDs)/(ultra-small nanoparticles) in a short time, at the air-liquid interface which can be suitably transferred by a well-known Blodgett technique to an appropriate substrate, (2) The method is suitable to apply layer by layer (LbL) technique to increase the film thickness as well as forming various compositions as revealed by AFM measurements. The films are characterized for their structure (SAED), morphology (TEM), optical properties (UV-Vis.) and photoluminescence (PL). Possible mechanism of formation of QDs thin film and effect of capping in case of CdS QDs is discussed.

  4. Low-thrust chemical orbit transfer propulsion

    NASA Technical Reports Server (NTRS)

    Pelouch, J. J., Jr.

    1979-01-01

    The need for large structures in high orbit is reported in terms of the many mission opportunities which require such structures. Mission and transportation options for large structures are presented, and it is shown that low-thrust propulsion is an enabling requirement for some missions and greatly enhancing to many others. Electric and low-thrust chemical propulsion are compared, and the need for an requirements of low-thrust chemical propulsion are discussed in terms of the interactions that are perceived to exist between the propulsion system and the large structure.

  5. Rocket thrust variation with foamed liquid propellants

    NASA Technical Reports Server (NTRS)

    Morrell, G

    1957-01-01

    An analysis is presented on a method for varying rocket thrust by varying the bulk density of the propellants. This density variation was accomplished by uniformly dispersing an inert, insoluble gas in the liquid propellants. Only qualitative agreement with theory was obtained from preliminary experiments with a 1000-pound-thrust ammonia - nitric acid rocket engine; the required experimental gas-flow rates were two to six times greater than those predicted by theory. It was demonstrated, however, that this method of rocket-thrust variation is feasible.

  6. Numerical simulation of 3-D temperature distribution of the flame tube of the combustion chamber with air film cooling

    NASA Astrophysics Data System (ADS)

    Chang, Haiping; Huang, Taiping; Chen, Wanbing

    1996-01-01

    The wall temperature distribution of the flame tube of the combustion chamber is strongly affected by the combustion, radiation and flow. The interaction of these influential factors forms a coupling system. In this paper, a new method, which is different from the previous methods, has been developed for calculating the temperature distribution of the flame tube wall together with the flow field inside and outside the flame tube. In the calculation, the combustion, heat radiation, cooling air film and injection stream mixing inside the flame tube as well as the secondary air flowing outside the flame tube have been simulated. The calculation, in this paper, uses the SIMPLE algorithm, the k - ɛ turbulence model and the auto-adjustable damping method. By using this method, the 3-D temperature distribution of the flame tube wall of the combustion chamber of an aeroengine has been simulated successfully. The calculation results are compared to the experimental data. The error of wall temperature is less than 10%.

  7. The Importance of Nanometric Passivating Films on Cathodes forLi - Air Batteries

    SciTech Connect

    Adams, Brian D.; Black, Robert; Radtke, Claudio; Williams, Zach; Mehdi, Beata L.; Browning, Nigel D.; Nazar, Linda F.

    2014-12-23

    Recently, there has been a transition from fully carbonaceous positive electrodes for the aprotic lithium oxygen battery to alternative materials and the use of redox mediator additives, in an attempt to lower the large electrochemical overpotentials associated with the charge reaction. However, the stabilizing or catalytic effect of these materials can become complicated due to the presence of major side-reactions observed during dis(charge). Here, we isolate the charge reaction from the discharge by utilizing electrodes prefilled with commercial lithium peroxide with a crystallite size of about 200-800 nm. Using a combination of S/TEM, online mass spectrometry, XPS, and electrochemical methods to probe the nature of surface films on carbon and conductive Ti-based nanoparticles, we show that oxygen evolution from lithium peroxide is strongly dependent on their surface properties. Insulating TiO2 surface layers on TiC and TiN - even as thin as 3 nm*can completely inhibit the charge reaction under these conditions. On the other hand, TiC, which lacks this oxide film, readily facilitates oxidation of the bulk Li2O2 crystallites, at a much lower overpotential relative to carbon. Since oxidation of lithium oxygen battery cathodes is inevitable in these systems, precise control of the surface chemistry at the nanoscale becomes of upmost importance.

  8. The importance of nanometric passivating films on cathodes for Li-air batteries.

    PubMed

    Adams, Brian D; Black, Robert; Radtke, Claudio; Williams, Zack; Mehdi, B Layla; Browning, Nigel D; Nazar, Linda F

    2014-12-23

    Recently, there has been a transition from fully carbonaceous positive electrodes for the aprotic lithium oxygen battery to alternative materials and the use of redox mediator additives, in an attempt to lower the large electrochemical overpotentials associated with the charge reaction. However, the stabilizing or catalytic effect of these materials can become complicated due to the presence of major side-reactions observed during dis(charge). Here, we isolate the charge reaction from the discharge by utilizing electrodes prefilled with commercial lithium peroxide with a crystallite size of about 200-800 nm. Using a combination of S/TEM, online mass spectrometry, XPS, and electrochemical methods to probe the nature of surface films on carbon and conductive Ti-based nanoparticles, we show that oxygen evolution from lithium peroxide is strongly dependent on their surface properties. Insulating TiO2 surface layers on TiC and TiN - even as thin as 3 nm-can completely inhibit the charge reaction under these conditions. On the other hand, TiC, which lacks this oxide film, readily facilitates oxidation of the bulk Li2O2 crystallites, at a much lower overpotential relative to carbon. Since oxidation of lithium oxygen battery cathodes is inevitable in these systems, precise control of the surface chemistry at the nanoscale becomes of upmost importance. PMID:25364863

  9. Toward air-stable multilayer phosphorene thin-films and transistors

    NASA Astrophysics Data System (ADS)

    Kim, Joon-Seok; Liu, Yingnan; Zhu, Weinan; Kim, Seohee; Wu, Di; Tao, Li; Dodabalapur, Ananth; Lai, Keji; Akinwande, Deji

    2015-03-01

    Few-layer black phosphorus (BP), also known as phosphorene, is poised to be the most attractive graphene analogue owing to its high mobility approaching that of graphene, and its thickness-tunable band gap that can be as large as that of molybdenum disulfide. In essence, phosphorene represents the much sought after high-mobility, large direct band gap two-dimensional layered crystal that is ideal for optoelectronics and flexible devices. However, its instability in air is of paramount concern for practical applications. Here, we demonstrate air-stable BP devices with dielectric and hydrophobic encapsulation. Microscopy, spectroscopy, and transport techniques were employed to elucidate the aging mechanism, which can initiate from the BP surface for bare samples, or edges for samples with thin dielectric coating, highlighting the ineffectiveness of conventional scaled dielectrics. Our months-long studies indicate that a double layer capping of Al2O3 and hydrophobic fluoropolymer affords BP devices and transistors with indefinite air-stability for the first time, overcoming a critical material challenge for applied research and development.

  10. Toward air-stable multilayer phosphorene thin-films and transistors.

    PubMed

    Kim, Joon-Seok; Liu, Yingnan; Zhu, Weinan; Kim, Seohee; Wu, Di; Tao, Li; Dodabalapur, Ananth; Lai, Keji; Akinwande, Deji

    2015-03-11

    Few-layer black phosphorus (BP), also known as phosphorene, is poised to be the most attractive graphene analogue owing to its high mobility approaching that of graphene, and its thickness-tunable band gap that can be as large as that of molybdenum disulfide. In essence, phosphorene represents the much sought after high-mobility, large direct band gap two-dimensional layered crystal that is ideal for optoelectronics and flexible devices. However, its instability in air is of paramount concern for practical applications. Here, we demonstrate air-stable BP devices with dielectric and hydrophobic encapsulation. Microscopy, spectroscopy, and transport techniques were employed to elucidate the aging mechanism, which can initiate from the BP surface for bare samples, or edges for samples with thin dielectric coating, highlighting the ineffectiveness of conventional scaled dielectrics. Our months-long studies indicate that a double layer capping of Al2O3 and hydrophobic fluoropolymer affords BP devices and transistors with indefinite air-stability for the first time, overcoming a critical material challenge for applied research and development.

  11. Toward air-stable multilayer phosphorene thin-films and transistors

    PubMed Central

    Kim, Joon-Seok; Liu, Yingnan; Zhu, Weinan; Kim, Seohee; Wu, Di; Tao, Li; Dodabalapur, Ananth; Lai, Keji; Akinwande, Deji

    2015-01-01

    Few-layer black phosphorus (BP), also known as phosphorene, is poised to be the most attractive graphene analogue owing to its high mobility approaching that of graphene, and its thickness-tunable band gap that can be as large as that of molybdenum disulfide. In essence, phosphorene represents the much sought after high-mobility, large direct band gap two-dimensional layered crystal that is ideal for optoelectronics and flexible devices. However, its instability in air is of paramount concern for practical applications. Here, we demonstrate air-stable BP devices with dielectric and hydrophobic encapsulation. Microscopy, spectroscopy, and transport techniques were employed to elucidate the aging mechanism, which can initiate from the BP surface for bare samples, or edges for samples with thin dielectric coating, highlighting the ineffectiveness of conventional scaled dielectrics. Our months-long studies indicate that a double layer capping of Al2O3 and hydrophobic fluoropolymer affords BP devices and transistors with indefinite air-stability for the first time, overcoming a critical material challenge for applied research and development. PMID:25758437

  12. Analysis of the gas-lubricated flat-sector-pad thrust bearing

    NASA Technical Reports Server (NTRS)

    Etsion, I.

    1976-01-01

    A flat sector-shaped pad geometry for a gas-lubricated thrust bearing is analyzed considering both the pitch and roll of the pad. It is shown that maximum load capacity is achieved when the pad is tilted so as to create uniform minimum film thickness along the pad trailing edge. Performance characteristics for various geometries and operating conditions of gas thrust bearings are presented in the form of design curves, and a comparison is made with the rectangular slider approximation. It is found that this approximation is unsafe for practical design, since it always overestimates load capacity.

  13. Test program to provide confidence in liquid oxygen cooling of hydrocarbon fueled rocket thrust chambers

    NASA Technical Reports Server (NTRS)

    Armstrong, Elizabeth S.

    1986-01-01

    In previous tests of liquid oxygen cooling of hydrocarbon fueled rocket engines, small oxygen leaks developed at the throat of the thrust chamber and film cooled the hot gas side of the chamber wall without resulting in catastrophic failure. However, more testing is necessary to demonstrate that a catastropic failure would not occur if cracks developed further upstream between the injector and the throat, where the boundary layer has not been established. Since under normal conditions cracks are expected to form in the throat region of the thrust chamber, cracks must be initiated artificially in order to control their location. Several methods of crack initiation are discussed here.

  14. Demonstration, Testing and Qualification of a High Temperature, High Speed Magnetic Thrust Bearing

    NASA Technical Reports Server (NTRS)

    DeWitt, Kenneth

    2005-01-01

    The gas turbine industry has a continued interest in improving engine performance and reducing net operating and maintenance costs. These goals are being realized because of advancements in aeroelasticity, materials, and computational tools such as CFD and engine simulations. These advancements aid in increasing engine thrust-to-weight ratios, specific fuel consumption, pressure ratios, and overall reliability through higher speed, higher temperature, and more efficient engine operation. Currently, rolling element bearing and squeeze film dampers are used to support rotors in gas turbine engines. Present ball bearing configurations are limited in speed (<2 million DN) and temperature (<5OO F) and require both cooling air and an elaborate lubrication system. Also, ball bearings require extensive preventative maintenance in order to assure their safe operation. Since these bearings are at their operational limits, new technologies must be found in order to take advantage of other advances. Magnetic bearings are well suited to operate at extreme temperatures and higher rotational speeds and are a promising solution to the problems that conventional rolling element bearings present. Magnetic bearing technology is being developed worldwide and is considered an enabling technology for new engine designs. Using magnetic bearings, turbine and compressor spools can be radically redesigned to be significantly larger and stiffer with better damping and higher rotational speeds. These advances, a direct result of magnetic bearing technology, will allow significant increases in engine power and efficiency. Also, magnetic bearings allow for real-time, in-situ health monitoring of the system, lower maintenance costs and down time.

  15. Thrust and power required in climbing

    NASA Technical Reports Server (NTRS)

    Koenig, George

    1923-01-01

    The following article shows that the phenomena of climbing flight can be determined with sufficient accuracy and represented very clearly, for all flight positions, by means of the thrust diagrams. This method has often given good results.

  16. 14 CFR 33.97 - Thrust reversers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.97 Thrust reversers. (a) If the engine incorporates a reverser, the endurance calibration, operation, and vibration tests prescribed...

  17. Three dimensional thrust chamber life prediction

    NASA Technical Reports Server (NTRS)

    Armstrong, W. H.; Brogren, E. W.

    1976-01-01

    A study was performed to analytically determine the cyclic thermomechanical behavior and fatigue life of three configurations of a Plug Nozzle Thrust Chamber. This thrust chamber is a test model which represents the current trend in nozzle design calling for high performance coupled with weight and volume limitations as well as extended life for reusability. The study involved the use of different materials and material combinations to evaluate their application to the problem of low-cycle fatigue in the thrust chamber. The thermal and structural analyses were carried out on a three-dimensional basis. Results are presented which show plots of continuous temperature histories and temperature distributions at selected times during the operating cycle of the thrust chamber. Computed structural data show critical regions for low-cycle fatigue and the histories of strain within the regions for each operation cycle.

  18. Comparative investigation of multiplane thrust vectoring nozzles

    NASA Technical Reports Server (NTRS)

    Capone, F.; Smereczniak, P.; Spetnagel, D.; Thayer, E.

    1992-01-01

    The inflight aerodynamic performance of multiplane vectoring nozzles is critical to development of advanced aircraft and flight control systems utilizing thrust vectoring. To investigate vectoring nozzle performance, subscale models of two second-generation thrust vectoring nozzle concepts currently under development for advanced fighters were integrated into an axisymmetric test pod. Installed drag and vectoring performance characteristics of both concepts were experimentally determined in wind tunnel testing. CFD analyses were conducted to understand the impact of internal flow turning on thrust vectoring characteristics. Both nozzles exhibited drag comparable with current nonvectoring axisymmetric nozzles. During vectored-thrust operations, forces produced by external flow effects amounted to about 25 percent of the total force measured.

  19. Characterization of air-formed surface oxide film on a Co-Ni-Cr-Mo alloy (MP35N) and its change in Hanks' solution

    NASA Astrophysics Data System (ADS)

    Nagai, Akiko; Tsutsumi, Yusuke; Suzuki, Yuta; Katayama, Keiichi; Hanawa, Takao; Yamashita, Kimihiro

    2012-05-01

    The air-formed surface oxide films used for stents were characterized to determine their composition and chemical state on a Co-Ni-Cr-Mo alloy. The change of the films in Hanks' solution was used to estimate the reconstruction of the film in the human body. Angle-resolved X-ray photoelectron spectroscopy was used to characterize the composition of the film and substrate, as well as the film's thickness. The surface oxide film on the Co-Ni-Cr-Mo alloy (when mechanically polished) consists of oxide species of cobalt, nickel, chromium, and molybdenum, contains a large amount of OH-, and has a thickness of approximately 2.5 nm. Cations exist in the oxide as Co2+, Ni2+, Cr3+, Mo4+, Mo5+, and Mo6+. Chromium is enriched and cobalt and nickel are depleted in the oxide; however, nickel is enriched and cobalt is depleted in the substrate alloy just under the surface oxide film. Concentration of chromium was low and that of nickel was high at small take-off angles. This indicates that distribution of chromium is greater in the inner layer, but nickel is distributed more in the outer layer of the surface oxide film. During immersion in Hanks' solution, cobalt and nickel dissolved, and the film composition changed to mostly chromium oxide (Cr3+), along with small amounts of cobalt, nickel, and molybdenum oxides, and calcium phosphate containing magnesium, potassium, and carbonate. After immersion in Hanks' solution, the thickness of the surface layer containing calcium phosphate increased to more than 4 nm, while the amount of OH- increased. The amount of cobalt and nickel in the surface oxide film and in the substrate alloy just below the oxide decreased during immersion.

  20. GSFC Technology Thrusts and Partnership Opportunities

    NASA Technical Reports Server (NTRS)

    Le Moigne, Jacqueline

    2010-01-01

    This slide presentation reviews the technology thrusts and the opportunities to partner in developing software in support of the technological advances at the Goddard Space Flight Center (GSFC). There are thrusts in development of end-to-end software systems for mission data systems in areas of flight software, ground data systems, flight dynamic systems and science data systems. The required technical expertise is reviewed, and the supported missions are shown for the various areas given.

  1. Multiphysics Nuclear Thermal Rocket Thrust Chamber Analysis

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See

    2005-01-01

    The objective of this effort is t o develop an efficient and accurate thermo-fluid computational methodology to predict environments for hypothetical thrust chamber design and analysis. The current task scope is to perform multidimensional, multiphysics analysis of thrust performance and heat transfer analysis for a hypothetical solid-core, nuclear thermal engine including thrust chamber and nozzle. The multiphysics aspects of the model include: real fluid dynamics, chemical reactivity, turbulent flow, and conjugate heat transfer. The model will be designed to identify thermal, fluid, and hydrogen environments in all flow paths and materials. This model would then be used to perform non- nuclear reproduction of the flow element failures demonstrated in the Rover/NERVA testing, investigate performance of specific configurations and assess potential issues and enhancements. A two-pronged approach will be employed in this effort: a detailed analysis of a multi-channel, flow-element, and global modeling of the entire thrust chamber assembly with a porosity modeling technique. It is expected that the detailed analysis of a single flow element would provide detailed fluid, thermal, and hydrogen environments for stress analysis, while the global thrust chamber assembly analysis would promote understanding of the effects of hydrogen dissociation and heat transfer on thrust performance. These modeling activities will be validated as much as possible by testing performed by other related efforts.

  2. Thrusting and sedimentation along an emergent thrust front: an example from the External Sierras of the Southern Pyrenees, Spain

    SciTech Connect

    Anastasio, D.J.; De Paor, D.G.

    1985-01-01

    Depending on the relative rates of thrusting and erosion, emergent thrusts, like glaciers, may advance or retreat while continually moving forward. The relative rates of thrusting and erosion as a thrust ruptures the land surface also control the mountain front geometry. For listric thrusts, the high angle of intersection with the land surface results in primarily upward rather than horizontal movement. If thrust movement is much faster than the prevailing erosion a large emergent toe will develop as the thrust sheet advances over its synorogenic deposits. Alternatively, if the erosion rates are generally faster than thrusting, synorogenic deposits will progressively onlap onto a receding mountain front. Comparable rates of thrusting and erosion result in steady state uplift and denudation. In the External Sierras the thrust front reached the synorogenic surface during the Paleogene and resulted in the accumulation of thick synorogenic deposits. Relatively slow rates of thrusting (<1mm/a) and uplift (<0.5mm/a) of the External Sierras, coupled with moderate erosion rates resulted in a near stationary mountain front. Despite this, temporal and spatial fluctuations in the thrusting resulted in three different mountain front geometries. In places, the thrust front has been buried by molasse, elsewhere, the emergent thrust sheet has deformed its proximal molasse by bulldozing, producing deposits analogous to push moraines, and in other places the frontal thrust has overridden its molasse. Striated cobbles within the molasse immediately below the frontal thrust may have functioned like ball bearings, reducing the friction with the overriding thrust sheet.

  3. 4. COMPLETE X15 VEHICLE TEST STAND, DETAIL OF THRUST MOUNTING ...

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

    4. COMPLETE X-15 VEHICLE TEST STAND, DETAIL OF THRUST MOUNTING STRUCTURE AT ENGINE END OF PLANE. - Edwards Air Force Base, X-15 Engine Test Complex, Rocket Engine & Complete X-15 Vehicle Test Stands, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

  4. Dryden/Edwards 1994 Thrust-Vectoring Aircraft Fleet - F-18 HARV, X-31, F-16 MATV

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The three thrust-vectoring aircraft at Edwards, California, each capable of flying at extreme angles of attack, cruise over the California desert in formation during flight in March 1994. They are, from left, NASA's F-18 High Alpha Research Vehicle (HARV), flown by the NASA Dryden Flight Research Center; the X-31, flown by the X-31 International Test Organization (ITO) at Dryden; and the Air Force F-16 Multi-Axis Thrust Vectoring (MATV) aircraft. All three aircraft were flown in different programs and were developed independently. The NASA F-18 HARV was a testbed to produce aerodynamic data at high angles of attack to validate computer codes and wind tunnel research. The X-31 was used to study thrust vectoring to enhance close-in air combat maneuvering, while the F-16 MATV was a demonstration of how thrust vectoring could be applied to operational aircraft.

  5. Static investigation of two fluidic thrust-vectoring concepts on a two-dimensional convergent-divergent nozzle

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    1994-01-01

    A static investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel of two thrust-vectoring concepts which utilize fluidic mechanisms for deflecting the jet of a two-dimensional convergent-divergent nozzle. One concept involved using the Coanda effect to turn a sheet of injected secondary air along a curved sidewall flap and, through entrainment, draw the primary jet in the same direction to produce yaw thrust vectoring. The other concept involved deflecting the primary jet to produce pitch thrust vectoring by injecting secondary air through a transverse slot in the divergent flap, creating an oblique shock in the divergent channel. Utilizing the Coanda effect to produce yaw thrust vectoring was largely unsuccessful. Small vector angles were produced at low primary nozzle pressure ratios, probably because the momentum of the primary jet was low. Significant pitch thrust vector angles were produced by injecting secondary flow through a slot in the divergent flap. Thrust vector angle decreased with increasing nozzle pressure ratio but moderate levels were maintained at the highest nozzle pressure ratio tested. Thrust performance generally increased at low nozzle pressure ratios and decreased near the design pressure ratio with the addition of secondary flow.

  6. Interaction of N-myristoylethanolamine with cholesterol investigated in a Langmuir film at the air-water interface.

    PubMed

    Kamlekar, Ravi Kanth; Chandra, M Sharath; Radhakrishnan, T P; Swamy, Musti J

    2009-01-01

    The dramatic increase in the content of N-acylethanolamines (NAEs) having different acyl chains in various tissues when subjected to stress has resulted in significant interest in investigations on these molecules. Previous studies suggested that N-myristoylethanolamine (NMEA) and cholesterol interact to form a 1:1 (mol/mol) complex. In studies reported here, pressure-area isotherms of Langmuir films at the air-water interface have shown that at low fractions of cholesterol, the average area per molecule is lower than that predicted for ideal mixing, whereas at high cholesterol content the observed molecular area is higher, with a cross-over point at the equimolar composition. A plausible model that can explain these observations is the following: addition of small amounts of cholesterol to NMEA results in a reorientation of the NMEA molecules from the tilted disposition in the crystalline state to the vertical and stabilization of the intermolecular interactions, leading to the formation of a compact monolayer film, whereas at the other end of the composition diagram, addition of small amounts of NMEA to cholesterol leads to a tilting of the cholesterol molecules resulting in an increase in the average area per molecule. In Brewster angle microscopy experiments, a stable and bright homogeneous condensed phase was observed at a relatively low applied pressure of 2 mN.m(-1) for the NMEA:Chol. (1:1, mol/mol) mixture, whereas all other samples required significantly higher pressures (>10 mN.m(-1)) to form a homogeneous condensed phase. These observations are consistent with the formation of a 1:1 stoichiometric complex between NMEA and cholesterol and suggest that increase in the content of NAEs under stress may modulate the composition and dynamics of lipid rafts in biological membranes, resulting in alterations in signaling events involving them, which may be relevant to the putative cytoprotective and stress-combating ability of NAEs.

  7. Simulations of Pulse Detonation Engines with MHD Thrust Augmentation

    NASA Astrophysics Data System (ADS)

    Zeineh, Christopher; Roth, Timothy; Cole, Lord; Karagozian, Ann; Cambier, Jean-Luc

    2008-11-01

    Pulse detonation rocket engines (PDREs) have received significant attention in recent years due to their potentially superior performance over constant-pressure engines. Yet unsteady chamber pressures cause the PDRE flow to be either over-expanded or under-expanded for the majority of the cycle, with substantial performance loss in atmospheric flight applications. The present computational studies examine the potential benefits of using magneto-hydrodynamic (MHD) thrust augmentation by extracting energy via a generator in the PDRE nozzle and applying it to a separate, secondary stream. In the present studies, which involve both transient quasi-1D and 2D numerical simulations, the energy extracted from the nozzle flow is directly applied to a by-pass air stream through an MHD accelerator. The air stream is first shocked by the under-expanded nozzle flow and raised to high temperature, allowing thermal ionization. The specific conditions for thrust augmentation are examined. Alternative configurations utilizing a magnetic piston in the PDRE chamber are also explored. Results show potential performance gains but with significant challenges, depending on the operating and flight conditions.

  8. Cape Canaveral Air Force Station, Launch Complex 39, Solid Rocket ...

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

    Cape Canaveral Air Force Station, Launch Complex 39, Solid Rocket Booster Disassembly & Refurbishment Complex, Thrust Vector Control Deservicing Facility, Hangar Road, Cape Canaveral, Brevard County, FL

  9. Investigation into the optoelectrical properties of tungsten oxide thin films annealed in an oxygen air

    SciTech Connect

    Arfaoui, A.; Ouni, B. Touihri, S.; Mannoubi, T.

    2014-12-15

    Tungsten oxide (WO{sub x}) thin film have been deposited onto glass substrates using the thermal vacuum evaporation technique, monitored by an annealing process in a variable oxygen atmosphere. Analysis by X-ray diffraction and Raman spectroscopy showed the structural changes from orthorhombic to monoclinic which depend on the annealing temperature and the oxygen content. AFM study shows that the increase of oxygen content leads to a decrease of the root-mean-square from 94.64 nm to 2 nm. Ellipsometric measurements have been used to evaluate the optical constants. Further, it is found that when the oxygen content increases, the band gap of the annealed layer varies from 3.01 eV to 3.52 eV by against, the Urbach energy decreases. The AC conductivity plot showed a universal power law according to the Jonscher model. Moreover, at high frequency semiconductor-to-metallic behavior has been observed. Finally, the effect of annealing in oxygen atmosphere on their structural modifications, morphological, optical properties and electrical conductivity are reported.

  10. Middle Proterozoic thrusting in central New Mexico

    SciTech Connect

    Grambling, J.A.; Thompson, A.G. . Dept. of Earth and Planetary Sciences); Dallmeyer, R.D. . Dept. of Geology)

    1992-01-01

    Ductile thrust faults truncate contact-metamorphic aureoles surrounding two 1.4 Ga plutons in central New Mexico. The Priest quartz monzonite (1440 Ma) and Sandia granite (1420 Ma) are 50 km apart in the continuous Sandia/Manzano mountain chain. Thermobarometry and phase relations demonstrate that country-rock temperatures rose from 700 C toward the pluton, at pressure near 4 kb. The northern edge of this aureole is cut by the southeast-dipping ductile Monte Largo thrust fault. Prograde, greenschist-facies metamorphism of footwall rocks accompanied local retrogression of hangingwall rocks during thrusting. This second metamorphism took place at P-T conditions of 2-3 kb and 450-475 C. Another contact aureole surrounds the Sandia granite. Mafic rocks near the granite reflect amphibolite-facies conditions, whereas pelites display low-pressure contact assemblages. Quantitative temperatures increase from 500--750 C toward the granite, at pressures of 2.5--3.5 kb. The shallowly southeast-dipping Vincent Moore fault truncates the Sandia granite and the southern portion of its contact aureole. This ductile shear zone emplaced greenschist-facies rocks northwestward above the Sandia contact aureole. Footwall rocks were retrograded to the greenschist facies within 100 m of this fault; the retrograde phases are aligned parallel to the trace of the thrust. Metamorphic temperatures in hangingwall rocks (during thrusting ) were 400-475 C at pressures above 2.75 kb. Additional northwest-vergent ductile thrusts are found elsewhere in the mountain chain. This may represent the age of thrusting and of the related greenschist and the related greenschist-facies metamorphic overprint.

  11. On the Thrust of a Single Electrode Electrohydrodynamic Thruster

    NASA Astrophysics Data System (ADS)

    Ilit', Tomáš; Váry, Michal; Valko, Pavol

    2015-03-01

    Linear thrust generation by a single pin emitter electrode under AC excitation has been studied. Presented are thrust measurements of a single electrode thruster, in comparison with classical, two electrode electrohydrodynamic thruster. The experiments show comparable thrust for both configurations at low voltage levels, suggesting higher thrust-to-weight ratio of single electrode thrusters at low applied voltages. Further, a hypothesis of single electrode thrust creation is proposed.

  12. Model of low-thrust pulse detonation device with valveless fuel feed

    NASA Astrophysics Data System (ADS)

    Baklanov, D. I.; Golovastov, S. V.; Golub, V. V.; Semin, N. V.; Volodin, V. V.

    2009-09-01

    A model pulse detonation engine of low thrust is designed. A valveless fuel and oxidant feed was used to fill a combustion chamber. The detonation was formed in the flow of mixed fuel and oxidant. The influence of oxidant on the engine operation mode, the influence of ring obstacles and prechambers on deflagration-to-detonation transition (DDT), and the influence of fuel on engine output parameters were investigated. Air-hydrogen and air-hydrocarbon mixtures were used.

  13. X-ray Lithography on Perovskite Nanocrystals Films: From Patterning with Anion-Exchange Reactions to Enhanced Stability in Air and Water

    PubMed Central

    2015-01-01

    Films of colloidal CsPbX3 (X = I, Br or Cl) nanocrystals, prepared by solution drop-casting or spin-coating on a silicon substrate, were exposed to a low flux of X-rays from an X-ray photoelectron spectrometer source, causing intermolecular C=C bonding of the organic ligands that coat the surface of the nanocrystals. This transformation of the ligand shell resulted in a greater stability of the film, which translated into the following features: (i) Insolubility of the exposed regions in organic solvents which caused instead complete dissolution of the unexposed regions. This enabled the fabrication of stable and strongly fluorescent patterns over millimeter scale areas. (ii) Inhibition of the irradiated regions toward halide anion exchange reactions, when the films were exposed either to halide anions in solution or to hydrohalic vapors. This feature was exploited to create patterned regions of different CsPbIxBryClz compositions, starting from a film with homogeneous CsPbX3 composition. (iii) Resistance of the films to degradation caused by exposure to air and moisture, which represents one of the major drawbacks for the integration of these materials in devices. (iv) Stability of the film in water and biological buffer, which can open interesting perspectives for applications of halide perovskite nanocrystals in aqueous environments. PMID:26617344

  14. Thrust Stand for Electric Propulsion Performance Evaluation

    NASA Technical Reports Server (NTRS)

    Markusic, T. E.; Jones, J. E.; Cox, M. D.

    2004-01-01

    An electric propulsion thrust stand capable of supporting thrusters with total mass of up to 125 kg and 1 mN to 1 N thrust levels has been developed and tested. The mechanical design features a conventional hanging pendulum arm attached to a balance mechanism that transforms horizontal motion into amplified vertical motion, with accommodation for variable displacement sensitivity. Unlike conventional hanging pendulum thrust stands, the deflection is independent of the length of the pendulum arm, and no reference structure is required at the end of the pendulum. Displacement is measured using a non-contact, optical linear gap displacement transducer. Mechanical oscillations are attenuated using a passive, eddy current damper. An on-board microprocessor-based level control system, which includes a two axis accelerometer and two linear-displacement stepper motors, continuously maintains the level of the balance mechanism - counteracting mechanical %era drift during thruster testing. A thermal control system, which includes heat exchange panels, thermocouples, and a programmable recirculating water chiller, continuously adjusts to varying thermal loads to maintain the balance mechanism temperature, to counteract thermal drifts. An in-situ calibration rig allows for steady state calibration both prior to and during thruster testing. Thrust measurements were carried out on a well-characterized 1 kW Hall thruster; the thrust stand was shown to produce repeatable results consistent with previously published performance data.

  15. Static performance of a cruciform nozzle with multiaxis thrust-vectoring and reverse-thrust capabilities

    NASA Technical Reports Server (NTRS)

    Wing, David J.; Asbury, Scott C.

    1992-01-01

    A multiaxis thrust vectoring nozzle designed to have equal flow turning capability in pitch and yaw was conceived and experimentally tested for internal, static performance. The cruciform-shaped convergent-divergent nozzle turned the flow for thrust vectoring by deflecting the divergent surfaces of the nozzle, called flaps. Methods for eliminating physical interference between pitch and yaw flaps at the larger multiaxis deflection angles was studied. These methods included restricting the pitch flaps from the path of the yaw flaps and shifting the flow path at the throat off the nozzle centerline to permit larger pitch-flap deflections without interfering with the operation of the yaw flaps. Two flap widths were tested at both dry and afterburning settings. Vertical and reverse thrust configurations at dry power were also tested. Comparison with two dimensional convergent-divergent nozzles showed lower but still competitive thrust performance and thrust vectoring capability.

  16. Genesis of Bénard-Marangoni Patterns in Thin Liquid Films Drying into Air

    NASA Astrophysics Data System (ADS)

    Colinet, P.; Chauvet, F.; Dehaeck, S.

    Inspired by many years of motivating collaboration between the first author and Prof. Manuel G. Velarde, in the field of surface-tension-driven instabilities, pattern formation, and transition to turbulence, this paper presents recent experimental results obtained in collaboration with the second and third authors at the TIPs laboratory in Brussels. Namely, the evolution of Bénard-like patterns is explored for pure liquid layers evaporating into air, from chaotic regimes down to more stable structures with predominant hexagonal symmetry. Drying liquid layers indeed appear as a particularly simple example of system where, due to the decreasing liquid depth, the preferred wavelength of the pattern is continuously decreased in time, hence requiring perpetual creation of new convective cells. Such pattern "genesis" appears to lead to disordered structures with interesting characteristics, whose preliminary experimental investigation is carried out here. This paper is dedicated to Prof. Manuel G. Velarde, at the occasion of his 70th birthday, as a mark of deep gratitude for all positive scientific and cultural influences he had and he still has on many young scientists.

  17. Small field diode correction factors derived using an air core fibre optic scintillation dosimeter and EBT2 film

    NASA Astrophysics Data System (ADS)

    Ralston, Anna; Liu, Paul; Warrener, Kirbie; McKenzie, David; Suchowerska, Natalka

    2012-05-01

    There is no commercially available real-time dosimeter that can accurately measure output factors for field sizes down to 4 mm without the use of correction factors. Silicon diode detectors are commonly used but are not dosimetrically water equivalent, resulting in energy dependence and fluence perturbation. In contrast, plastic scintillators are nearly dosimetrically water equivalent. A fibre optic dosimeter (FOD) with a 0.8 mm3 plastic scintillator coupled to an air core light guide was used to measure the output factors for Novalis/BrainLab stereotactic cones of diameter 4-30 mm and Novalis MLC fields of width 5-100 mm. The FOD data matched the output factors measured by a 0.125 cm3 Semiflex ion chamber for the MLC fields above 30 mm and those measured with the EBT2 radiochromic film for the cones and MLC fields below 30 mm. Relative detector readings were obtained with four diode types (IBA SFD, EFD, PFD, PTW 60012) for the same fields. Empirical diode correction factors were determined by taking the ratio of FOD output factors to diode relative detector readings. The diodes were found to over-respond by 3%-16% for the smallest field. There was good agreement between different diodes of the same model number.

  18. Aerodynamic performance of a fully film cooled core turbine vane tested with cold air in a two-dimensional cascade

    NASA Technical Reports Server (NTRS)

    Stabe, R. G.; Kline, J. F.

    1975-01-01

    The aerodynamic performance of a fully film cooled core turbine vane was investigated experimentally in a two-dimensional cascade of 10 vanes. Three of the 10 vanes were cooled; the others were solid (uncooled) vanes. Cold air was used for both the primary and coolant flows. The cascade test covered a range of pressure ratios corresponding to ideal exit critical velocity ratios of 0.6 to 0.95 and a range of coolant flow rates to 7.5 percent of the primary flow. The coolant flow was varied by changing the coolant supply pressure. The principal measurements were cross-channel surveys of exit total pressure, static pressure, and flow angle. The results presented include exit survey data and overall performance in terms of loss, flow angle, and weight flow for the range of exit velocity ratios and coolant flows investigated. The performance of the cooled vane is compared with the performance of an uncooled vane of the same profile and also with the performance obtained with a single cooled vane in the 10-vane cascade.

  19. Functionalization of Hydrogen-free Diamond-like Carbon Films using Open-air Dielectric Barrier Discharge Atmospheric Plasma Treatments

    SciTech Connect

    Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Instituto de Materiales de Madrid, C.S.I.C., Cantoblanco, 28049 Madrid, Spain; Instituto de Quimica-Fisica"Rocasolano"C.S.I.C., 28006 Madrid, Spain; Mahasarakham University, Mahasarakham 44150, Thailand; CASTI, CNR-INFM Regional Laboratory, L'Aquila 67100, Italy; SUNY Upstate Medical University, Syracuse, NY 13210, USA; Endrino, Jose; Endrino, J. L.; Marco, J. F.; Poolcharuansin, P.; Phani, A.R.; Allen, M.; Albella, J. M.; Anders, A.

    2007-12-28

    A dielectric barrier discharge (DBD) technique has been employed to produce uniform atmospheric plasmas of He and N2 gas mixtures in open air in order to functionalize the surface of filtered-arc deposited hydrogen-free diamond-like carbon (DLC) films. XPS measurements were carried out on both untreated and He/N2 DBD plasma treated DLC surfaces. Chemical states of the C 1s and N 1s peaks were collected and used to characterize the surface bonds. Contact angle measurements were also used to record the short- and long-term variations in wettability of treated and untreated DLC. In addition, cell viability tests were performed to determine the influence of various He/N2 atmospheric plasma treatments on the attachment of osteoblast MC3T3 cells. Current evidence shows the feasibility of atmospheric plasmas in producing long-lasting variations in the surface bonding and surface energy of hydrogen-free DLC and consequently the potential for this technique in the functionalization of DLC coated devices.

  20. Superhydrophobic metallic surfaces functionalized via femtosecond laser surface processing for long term air film retention when submerged in liquid

    NASA Astrophysics Data System (ADS)

    Zuhlke, Craig A.; Anderson, Troy P.; Li, Pengbo; Lucis, Michael J.; Roth, Nick; Shield, Jeffrey E.; Terry, Benjamin; Alexander, Dennis R.

    2015-03-01

    Femtosecond laser surface processing (FLSP) is a powerful technique used to create self-organized microstructures with nanoscale features on metallic surfaces. By combining FLSP surface texturing with surface chemistry changes, either induced by the femtosecond laser during processing or introduced through post processing techniques, the wetting properties of metals can be altered. In this work, FLSP is demonstrated as a technique to create superhydrophobic surfaces on grade 2 titanium and 304 stainless steel that can retain an air film (plastron) between the surface and a surrounding liquid when completely submerged. It is shown that the plastron lifetime when submerged in distilled water or synthetic stomach acid is critically dependent on the specific degree of surface micro- and nano-roughness, which can be tuned by controlling various FLSP parameters. The longest plastron lifetime was on a 304 stainless steel sample that was submerged in distilled water and maintained a plastron for 41 days, the length of time of the study, with no signs of degradation. Also demonstrated for the first time is the precise control of pulse fluence and pulse count to produce three unique classes of surface micron/nano-structuring on titanium.

  1. Initiation of subduction by post-collision foreland thrusting and back-thrusting

    NASA Astrophysics Data System (ADS)

    Mitchell, A. H. G.

    1984-07-01

    While postulated causes of initial subduction and trench formation include underthrusting, controls on its location and age have not been determined. Consideration of the age of subduction zones bordering five collisional orogens suggests that subduction may have been initiated by foreland thrusts and back-thrusts. Foreland thrusts develop within a continental foreland on the subducting plate mostly within 50 my of collision with an arc system; where the foreland is narrow the thrusts may intersect the continent-ocean crust boundary. Back-thrusts develop in the fore-arc or back-arc area on the overriding plate within 10 to 20 my of collision, and can result in tectonic burial of the magmatic arc; where the arc system is oceanic the back-thrusts may intersect the arc-ocean crust boundary. Possible examples of subduction initiated by foreland thrusts are the start of subduction in the late Jurassic beneath the northern Sunda Arc, and at the end-Miocene in the Negros Trench. Examples of back-thrusts which have initiated or may initiate subduction are the late Cenozoic eastward translation of Taiwan over the Philippine Sea plate, the incipient southward subduction of the Banda Sea beneath Timor, and the W-dipping back-thrust comprising the Highland Boundary Fault zone and postulated early Ordovician thrusts to the SE in Scotland. The suggested relationship of subduction to collision helps to explain the persistence of Wilson cycles in the still-active late Mesozoic to Cenozoic orogenic belts and implies that orogeny will cease only with collision between major continents.

  2. Large-scale recrystallization of the S-layer of Bacillus coagulans E38-66 at the air/water interface and on lipid films.

    PubMed Central

    Pum, D; Weinhandl, M; Hödl, C; Sleytr, U B

    1993-01-01

    S-layer protein isolated from Bacillus coagulans E38-66 could be recrystallized into large-scale coherent monolayers at an air/water interface and on phospholipid films spread on a Langmuir-Blodgett trough. Because of the asymmetry in the physiochemical surface properties of the S-layer protein, the subunits were associated with their more hydrophobic outer face with the air/water interface and oriented with their negatively charged inner face to the zwitterionic head groups of the dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylethanolamine (DPPE) monolayer films. The dynamic crystal growth at both types of interfaces was first initiated at several distant nucleation points. The individual monocrystalline areas grew isotropically in all directions until the front edge of neighboring crystals was met. The recrystallized S-layer protein and the S-layer-DPPE layer could be chemically cross-linked from the subphase with glutaraldehyde. Images PMID:8478338

  3. Status of Low Thrust Work at JSC

    NASA Technical Reports Server (NTRS)

    Condon, Gerald L.

    2004-01-01

    High performance low thrust (solar electric, nuclear electric, variable specific impulse magnetoplasma rocket) propulsion offers a significant benefit to NASA missions beyond low Earth orbit. As NASA (e.g., Prometheus Project) endeavors to develop these propulsion systems and associated power supplies, it becomes necessary to develop a refined trajectory design capability that will allow engineers to develop future robotic and human mission designs that take advantage of this new technology. This ongoing work addresses development of a trajectory design and optimization tool for assessing low thrust (and other types) trajectories. This work targets to advance the state of the art, enable future NASA missions, enable science drivers, and enhance education. This presentation provides a summary of the low thrust-related JSC activities under the ISP program and specifically, provides a look at a new release of a multi-gravity, multispacecraft trajectory optimization tool (Copernicus) along with analysis performed using this tool over the past year.

  4. Oil-Free Turbomachinery Research Enhanced by Thrust Bearing Test Capability

    NASA Technical Reports Server (NTRS)

    Bauman, Steven W.

    2003-01-01

    NASA Glenn Research Center s Oil-Free Turbomachinery research team is developing aircraft turbine engines that will not require an oil lubrication system. Oil systems are required today to lubricate rolling-element bearings used by the turbine and fan shafts. For the Oil-Free Turbomachinery concept, researchers combined the most advanced foil (air) bearings from industry with NASA-developed high-temperature solid lubricant technology. In 1999, the world s first Oil-Free turbocharger was demonstrated using these technologies. Now we are working with industry to demonstrate Oil-Free turbomachinery technology in a small business jet engine, the EJ-22 produced by Williams International and developed during Glenn s recently concluded General Aviation Propulsion (GAP) program. Eliminating the oil system in this engine will make it simpler, lighter (approximately 15 percent), more reliable, and less costly to purchase and maintain. Propulsion gas turbines will place high demands on foil air bearings, especially the thrust bearings. Up until now, the Oil-Free Turbomachinery research team only had the capability to test radial, journal bearings. This research has resulted in major improvements in the bearings performance, but journal bearings are cylindrical, and can only support radial shaft loads. To counteract axial thrust loads, thrust foil bearings, which are disk shaped, are required. Since relatively little research has been conducted on thrust foil air bearings, their performance lags behind that of journal bearings.

  5. An Oil-Free Thrust Foil Bearing Facility Design, Calibration, and Operation

    NASA Technical Reports Server (NTRS)

    Bauman, Steve

    2005-01-01

    New testing capabilities are needed in order to foster thrust foil air bearing technology development and aid its transition into future Oil-Free gas turbines. This paper describes a new test apparatus capable of testing thrust foil air bearings up to 100 mm in diameter at speeds to 80,000 rpm and temperatures to 650 C (1200 F). Measured parameters include bearing torque, load capacity, and bearing temperatures. This data will be used for design performance evaluations and for validation of foil bearing models. Preliminary test results demonstrate that the rig is capable of testing thrust foil air bearings under a wide range of conditions which are anticipated in future Oil-Free gas turbines. Torque as a function of speed and temperature corroborates results expected from rudimentary performance models. A number of bearings were intentionally failed with no resultant damage whatsoever to the test rig. Several test conditions (specific speeds and loads) revealed undesirable axial shaft vibrations which have been attributed to the magnetic bearing control system and are under study. Based upon these preliminary results, this test rig will be a valuable tool for thrust foil bearing research, parametric studies and technology development.

  6. Influence of variable thrust parameters on swirl injector fluid mechanics

    NASA Astrophysics Data System (ADS)

    Kenny, Robert J.

    Current swirl injector design methodologies do not consider elevated chamber pressure and less than design mass flow rate operation found in variable thrust liquid rocket engines. The objective of this work is to study the effects of elevated chamber pressure and off-design mass flow rate operation on swirl injector fluid mechanics. Using a high pressure chamber, water flowed through a swirl injector at various combinations of elevated chamber pressure and reduced mass flow rate. The optically-accessible swirl injector allowed for determination of the film thickness profile down the swirl injector nozzle section. High speed video and digital stills showed significant increases in the film thickness profile at high chamber pressure and low mass flow rate operation. At prescribed combinations of chamber pressure and mass flow rate, a jump was noted in the film thickness profile. This jump was assumed related to a vortex breakdown phenomenon. Measured injector discharge coefficient values showed different trends with increasing chamber pressure at low mass flow rate operation as opposed to near-design mass flow rate operation. Downstream spray angles showed classic changes in morphology as the mass flow rate was decreased below the design value. Increasing chamber pressure worked to decrease the spray angle at any injection mass flow rate. A new set of fundamental relations linking swirl injector design parameters to injector geometry and flow conditions were derived. Impacts of the research findings to the swirl injector design process were assessed.

  7. Test plan pressure fed thrust chamber technology

    NASA Technical Reports Server (NTRS)

    Dunn, Glenn

    1990-01-01

    Aerojet is developing the technology for the design of a reliable, low cost, efficient, and lightweight LOX/RP-1 pressure fed engine. This technology program is a direct result of Aerojet's liquid rocket booster (LRB) study and previous NASA studies that identified liquid engines using high bulk density hydrocarbon fuels as very attractive for a space transportation system (STS). Previous large thrust LOX/RP-1 engine development programs were characterized by costly development problems due to combustion instability damage. The combustion stability solution was typically obtained through trial and error methods of minimizing instability damage by degrading engine performance. The approach to this program was to utilize existing and newly developed combustion analysis models and design methodology to create a thrust chamber design with features having the potential of producing reliable and efficient operation. This process resulted in an engine design with a unique high thrust-per-element OFO triplet injector utilizing a low cost modular approach. Cost efficient ablative materials are baselined for the injector face and chamber. Technology demonstration will be accomplished through a hot fire test program using appropriately sized subscale hardware. This subscale testing will provide a data base to supplement the current industry data bank and to anchor and validate the applied analysis models and design methodology. Once anchored and validated, these analysis models and design methodology can be applied with greatly increased confidence to design and characterize a large scale pressure fed LOX/RP-1 thrust chamber. The objective of this test program is to generate a data base that can be used to anchor and validate existing analysis models and design methodologies and to provide early concept demonstration of a low cost, efficient LOX/RP-1 thrust chamber. Test conditions and hardware instrumentation were defined to provide data sufficient to characterize combustion

  8. Wing design with attainable thrust considerations

    NASA Technical Reports Server (NTRS)

    Carlson, H. W.; Shrout, B. L.; Darden, C. M.

    1984-01-01

    A CAD process that includes leading-edge thrust considerations for wings with high aerodynamic efficiencies is outlined. Rectangular grids are used for evaluation of both subsonic and supersonic pressure loadings. Account is taken of the Mach number, Re, the wing planform, the presence of camber, the airfoil geometry and the locations and forces induced by shed vortices. Optimization techniques are applied to the candidate surfaces in order to consider the attainable thrust. Inclusion of the optimization techniques permits analyses of mission-adaptive wings and various flap systems and the elimination of singularities in the flight envelope.

  9. SEP thrust subsystem performance sensitivity analysis

    NASA Technical Reports Server (NTRS)

    Atkins, K. L.; Sauer, C. G., Jr.; Kerrisk, D. J.

    1973-01-01

    This is a two-part report on solar electric propulsion (SEP) performance sensitivity analysis. The first part describes the preliminary analysis of the SEP thrust system performance for an Encke rendezvous mission. A detailed description of thrust subsystem hardware tolerances on mission performance is included together with nominal spacecraft parameters based on these tolerances. The second part describes the method of analysis and graphical techniques used in generating the data for Part 1. Included is a description of both the trajectory program used and the additional software developed for this analysis. Part 2 also includes a comprehensive description of the use of the graphical techniques employed in this performance analysis.

  10. Electromechanical actuation for thrust vector control applications

    NASA Astrophysics Data System (ADS)

    Roth, Mary Ellen

    At present, actuation systems for the Thrust Vector Control (TVC) for launch vehicles are hydraulic systems. The Advanced Launch System (ALS), a joint initiative between NASA and the Air Force, is a launch vehicle that is designed to be cost effective, highly reliable and operationally efficient with a goal of reducing the cost per pound to orbit. As part of this initiative, an electromechanical actuation system is being developed as an attractive alternative to the hydraulic systems used today. NASA-Lewis is developing and demonstrating an Induction Motor Controller Actuation System with a 40 hp peak rating. The controller will integrate 20 kHz resonant link Power Management and Distribution (PMAD) technology and Pulse Population Modulation (PPM) techniques to implement Field Oriented Vector Control (FOVC) of a new advanced induction motor. Through PPM, multiphase variable frequency, variable voltage waveforms can be synthesized from the 20 kHz source. FOVC shows that varying both the voltage and frequency and their ratio (V/F), permits independent control of both torque and speed while operating at maximum efficiency at any point on the torque-speed curve. The driver and the FOVC will be microprocessor controlled. For increased system reliability, a Built-in Test (BITE) capability will be included. This involves introducing testability into the design of a system such that testing is calibrated and exercised during the design, manufacturing, maintenance and prelaunch activities. An actuator will be integrated with the motor controller for performance testing of the EMA TVC system. The design and fabrication of the motor controller is being done by General Dynamics Space Systems Division. The University of Wisconsin-Madison will assist in the design of the advanced induction motor and in the implementation of the FOVC theory. A 75 hp electronically controlled dynamometer will be used to test the motor controller in all four quadrants of operation using flight type

  11. F-15B ACTIVE with thrust vectoring nozzles on test stand

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This November 13, 1995, photograph of the F-15 Advanced Controls Technology for Integrated Vehicles (ACTIVE) at NASA's Dryden Flight Research Center, Edwards, California, shows the thrust stand being used for ground testing of a new thrust-vectoring concept involving two new Pratt & Whitney nozzles that can turn up to 20 degrees in any direction. These nozzles give the aircraft thrust control in the pitch (up and down) and yaw (left and right) directions. This will reduce drag and increase fuel economy or range as compared with conventional aerodynamic controls, which increase the retarding forces (drag) acting upon the aircraft. These tests could lead to significant performance increases for military and commercial aircraft. The research program is the product of a collaborative effort by NASA, the Air Force's Wright Laboratory, Pratt & Whitney, and McDonnell Douglas Aerospace.

  12. Friction losses in a lubricated thrust-loaded cageless angular-contract bearing

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Allen, C. W.; Zaretsky, E. V.

    1973-01-01

    The NASA spinning torque apparatus was modified to measure the spinning torque on a cageless ball thrust bearing. Friction torque was measured for thrust loads varying from 44.5 to 403 newtons (10 to 90 lb) at speeds of 1000, 2000, and 3000 rpm. Tests were conducted with di-2-ethylhexyl sebacate and a synthetic paraffinic oil. These tests were run with either oil jet lubrication or with a thin surface film of lubricant only. An analytical model which included rolling resistance was developed and extended from previous models for spinning torque and lubricant rheology. The model was extended by the inclusion of rolling resistance. The computed values were in fair agreement with the experimental results and confirmed previous hypotheses that a thin lubricant film gives minimum bearing torque and an oil jet flow of a viscous lubricant will result in considerable rolling torque in addition to the torque due to ball spin.

  13. A microNewton thrust stand for average thrust measurement of pulsed microthruster

    NASA Astrophysics Data System (ADS)

    Zhou, Wei-Jing; Hong, Yan-Ji; Chang, Hao

    2013-12-01

    A torsional thrust stand has been developed for the study of the average thrust for microNewton pulsed thrusters. The main body of the thrust stand mainly consists of a torsional balance, a pair of flexural pivots, a capacitive displacement sensor, a calibration assembly, and an eddy current damper. The behavior of the stand was thoroughly studied. The principle of thrust measurement was analyzed. The average thrust is determined as a function of the average equilibrium angle displacement of the balance and the spring stiffness. The thrust stand has a load capacity up to 10 kg, and it can theoretically measure the force up to 609.6 μN with a resolution of 24.4 nN. The static calibrations were performed based on the calibration assembly composed of the multiturn coil and the permanent magnet. The calibration results demonstrated good repeatability (less than 0.68% FSO) and good linearity (less than 0.88% FSO). The assembly of the multiturn coil and the permanent magnet was also used as an exciter to simulate the microthruster to further research the performance of the thrust stand. Three sets of force pulses at 17, 33.5, and 55 Hz with the same amplitude and pulse width were tested. The repeatability error at each frequency was 7.04%, 1.78%, and 5.08%, respectively.

  14. A microNewton thrust stand for average thrust measurement of pulsed microthruster.

    PubMed

    Zhou, Wei-Jing; Hong, Yan-Ji; Chang, Hao

    2013-12-01

    A torsional thrust stand has been developed for the study of the average thrust for microNewton pulsed thrusters. The main body of the thrust stand mainly consists of a torsional balance, a pair of flexural pivots, a capacitive displacement sensor, a calibration assembly, and an eddy current damper. The behavior of the stand was thoroughly studied. The principle of thrust measurement was analyzed. The average thrust is determined as a function of the average equilibrium angle displacement of the balance and the spring stiffness. The thrust stand has a load capacity up to 10 kg, and it can theoretically measure the force up to 609.6 μN with a resolution of 24.4 nN. The static calibrations were performed based on the calibration assembly composed of the multiturn coil and the permanent magnet. The calibration results demonstrated good repeatability (less than 0.68% FSO) and good linearity (less than 0.88% FSO). The assembly of the multiturn coil and the permanent magnet was also used as an exciter to simulate the microthruster to further research the performance of the thrust stand. Three sets of force pulses at 17, 33.5, and 55 Hz with the same amplitude and pulse width were tested. The repeatability error at each frequency was 7.04%, 1.78%, and 5.08%, respectively.

  15. Self-consistent modelling of X-ray photoelectron spectra from air-exposed polycrystalline TiN thin films

    NASA Astrophysics Data System (ADS)

    Greczynski, G.; Hultman, L.

    2016-11-01

    We present first self-consistent modelling of x-ray photoelectron spectroscopy (XPS) Ti 2p, N 1s, O 1s, and C 1s core level spectra with a cross-peak quantitative agreement for a series of TiN thin films grown by dc magnetron sputtering and oxidized to different extent by varying the venting temperature Tv of the vacuum chamber before removing the deposited samples. So-obtained film series constitute a model case for XPS application studies, where certain degree of atmosphere exposure during sample transfer to the XPS instrument is unavoidable. The challenge is to extract information about surface chemistry without invoking destructive pre-cleaning with noble gas ions. All TiN surfaces are thus analyzed in the as-received state by XPS using monochromatic Al Kα radiation (hν = 1486.6 eV). Details of line shapes and relative peak areas obtained from deconvolution of the reference Ti 2p and N 1 s spectra representative of a native TiN surface serve as an input to model complex core level signals from air-exposed surfaces, where contributions from oxides and oxynitrides make the task very challenging considering the influence of the whole deposition process at hand. The essential part of the presented approach is that the deconvolution process is not only guided by the comparison to the reference binding energy values that often show large spread, but in order to increase reliability of the extracted chemical information the requirement for both qualitative and quantitative self-consistency between component peaks belonging to the same chemical species is imposed across all core-level spectra (including often neglected O 1s and C 1s signals). The relative ratios between contributions from different chemical species vary as a function of Tv presenting a self-consistency check for our model. We propose that the cross-peak self-consistency should be a prerequisite for reliable XPS peak modelling as it enhances credibility of obtained chemical information, while relying

  16. AIR Model Preflight Analysis

    NASA Technical Reports Server (NTRS)

    Tai, H.; Wilson, J. W.; Maiden, D. L.

    2003-01-01

    The atmospheric ionizing radiation (AIR) ER-2 preflight analysis, one of the first attempts to obtain a relatively complete measurement set of the high-altitude radiation level environment, is described in this paper. The primary thrust is to characterize the atmospheric radiation and to define dose levels at high-altitude flight. A secondary thrust is to develop and validate dosimetric techniques and monitoring devices for protecting aircrews. With a few chosen routes, we can measure the experimental results and validate the AIR model predictions. Eventually, as more measurements are made, we gain more understanding about the hazardous radiation environment and acquire more confidence in the prediction models.

  17. Facile and Scalable Fabrication of Highly Efficient Lead Iodide Perovskite Thin-Film Solar Cells in Air Using Gas Pump Method.

    PubMed

    Ding, Bin; Gao, Lili; Liang, Lusheng; Chu, Qianqian; Song, Xiaoxuan; Li, Yan; Yang, Guanjun; Fan, Bin; Wang, Mingkui; Li, Chengxin; Li, Changjiu

    2016-08-10

    Control of the perovskite film formation process to produce high-quality organic-inorganic metal halide perovskite thin films with uniform morphology, high surface coverage, and minimum pinholes is of great importance to highly efficient solar cells. Herein, we report on large-area light-absorbing perovskite films fabrication with a new facile and scalable gas pump method. By decreasing the total pressure in the evaporation environment, the gas pump method can significantly enhance the solvent evaporation rate by 8 times faster and thereby produce an extremely dense, uniform, and full-coverage perovskite thin film. The resulting planar perovskite solar cells can achieve an impressive power conversion efficiency up to 19.00% with an average efficiency of 17.38 ± 0.70% for 32 devices with an area of 5 × 2 mm, 13.91% for devices with a large area up to 1.13 cm(2). The perovskite films can be easily fabricated in air conditions with a relative humidity of 45-55%, which definitely has a promising prospect in industrial application of large-area perovskite solar panels.

  18. Facile and Scalable Fabrication of Highly Efficient Lead Iodide Perovskite Thin-Film Solar Cells in Air Using Gas Pump Method.

    PubMed

    Ding, Bin; Gao, Lili; Liang, Lusheng; Chu, Qianqian; Song, Xiaoxuan; Li, Yan; Yang, Guanjun; Fan, Bin; Wang, Mingkui; Li, Chengxin; Li, Changjiu

    2016-08-10

    Control of the perovskite film formation process to produce high-quality organic-inorganic metal halide perovskite thin films with uniform morphology, high surface coverage, and minimum pinholes is of great importance to highly efficient solar cells. Herein, we report on large-area light-absorbing perovskite films fabrication with a new facile and scalable gas pump method. By decreasing the total pressure in the evaporation environment, the gas pump method can significantly enhance the solvent evaporation rate by 8 times faster and thereby produce an extremely dense, uniform, and full-coverage perovskite thin film. The resulting planar perovskite solar cells can achieve an impressive power conversion efficiency up to 19.00% with an average efficiency of 17.38 ± 0.70% for 32 devices with an area of 5 × 2 mm, 13.91% for devices with a large area up to 1.13 cm(2). The perovskite films can be easily fabricated in air conditions with a relative humidity of 45-55%, which definitely has a promising prospect in industrial application of large-area perovskite solar panels. PMID:27428311

  19. Nonhomogeneous surface properties of parylene-C film etched by an atmospheric pressure He/O2 micro-plasma jet in ambient air

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Yang, Bin; Chen, Xiang; Wang, Xiaolin; Yang, Chunsheng; Liu, Jingquan

    2016-10-01

    Surface properties of parylene-C film etched by an atmospheric pressure He/O2 micro-plasma jet in ambient air were investigated. The morphologies and chemical compositions of the etched surface were analyzed by optical microscopy, SEM, EDS, XPS and ATR-FTIR. The microscopy and SEM images showed the etched surface was nonhomogeneous with six discernable ring patterns from the center to the outside domain, which were composed of (I) a central region; (II) an effective etching region, where almost all of the parylene-C film was removed by the plasma jet with only a little residual parylene-C being functionalized with carboxyl groups (Cdbnd O, Osbnd Cdbnd O-); (III) an inner etching boundary; (IV) a middle etching region, where the film surface was smooth and partially removed; (V) an outer etching boundary, where the surface was decorated with clusters of debris, and (VI) a pristine parylene-C film region. The analysis of the different morphologies and chemical compositions illustrated the different localized etching process in the distinct regions. Besides, the influence of O2 flow rate on the surface properties of the etched parylene-C film was also investigated. Higher volume of O2 tended to weaken the nonhomogeneous characteristics of the etched surface and improve the etched surface quality.

  20. Reverse thrust performance of the QCSEE variable pitch turbofan engine

    NASA Technical Reports Server (NTRS)

    Samanich, N. E.; Reemsnyder, D. C.; Blodmer, H. E.

    1980-01-01

    Results of steady state reverse and forward to reverse thrust transient performance tests are presented. The original quiet, clean, short haul, experimental engine four segment variable fan nozzle was retested in reverse and compared with a continuous, 30 deg half angle conical exlet. Data indicated that the significantly more stable, higher pressure recovery flow with the fixed 30 deg exlet resulted in lower engine vibrations, lower fan blade stress, and approximately a 20 percent improvement in reverse thrust. Objective reverse thrust of 35 percent of takeoff thrust was reached. Thrust response of less than 1.5 sec was achieved for the approach and the takeoff to reverse thrust transients.

  1. Development of a Lightweight Thrust Chamber Assembly Utilizing In-Situ Reinforced Silicon Nitride

    NASA Astrophysics Data System (ADS)

    Elvander, J.; Wherley, B.; Claflin, S.

    1999-06-01

    The paper describes the status of the Light Weight Thrust Chamber Assembly (LWTCA) program currently underway at Boeing Rocketdyne Propulsion and Power, under contract with the US Air Force Research Laboratory. The goal of the program is to demonstrate technology which will lead to a 40% reduction in weight (including the nozzle), a 50% reduction in cost, a 75% reduction in part count and a 3% increase in specific impulse on a full scale, 400 klbf thrust LOX/hydrogen booster engine. The demonstration will be performed through the use of manufacturing technology demonstrator hardware and 60 klbf thrust hot-fire tests. The primary means to achieving these goals is by using in-situ reinforced silicon nitride for structural components. Silicon nitride is an advanced ceramic material that has high specific strength and fracture toughness, and can be cast to near- net part shape. Tests to validate the material properties of in-situ reinforced silicon nitride are discussed, along with the resulting changes to traditional thrust chamber design as a result of the improved properties. The progress towards manufacturing and hot-fire testing a thrust chamber assembly from the material is also described.

  2. Parametric Investigation of Thrust Augmentation by Ejectors on a Pulsed Detonation Tube

    NASA Technical Reports Server (NTRS)

    Wilson, Jack; Sgondea, Alexandru; Paxson, Daniel E.; Rosenthal, Bruce N.

    2006-01-01

    A parametric investigation has been made of thrust augmentation of a 1 in. diameter pulsed detonation tube by ejectors. A set of ejectors was used which permitted variation of the ejector length, diameter, and nose radius, according to a statistical design of experiment scheme. The maximum augmentation ratios for each ejector were fitted using a polynomial response surface, from which the optimum ratios of ejector diameter to detonation tube diameter, and ejector length and nose radius to ejector diameter, were found. Thrust augmentation ratios above a factor of 2 were measured. In these tests, the pulsed detonation device was run on approximately stoichiometric air-hydrogen mixtures, at a frequency of 20 Hz. Later measurements at a frequency of 40 Hz gave lower values of thrust augmentation. Measurements of thrust augmentation as a function of ejector entrance to detonation tube exit distance showed two maxima, one with the ejector entrance upstream, and one downstream, of the detonation tube exit. A thrust augmentation of 2.5 was observed using a tapered ejector.

  3. Effect of ambient air on n-type carbon nanotube thin-film transistors chemically doped with poly(ethylene imine)

    NASA Astrophysics Data System (ADS)

    Yasunishi, Tomohiro; Kishimoto, Shigeru; Ohno, Yutaka

    2014-01-01

    Chemical doping with poly(ethylene imine) (PEI) is often used to produce n-type carbon nanotube thin-film transistors (CNT TFTs) with stability in air. However, the effect of air on the device characteristics has not yet been fully investigated. In this study, we performed a detailed investigation on how the oxygen and water present in air affect stability issues, including hysteresis, current collapse, and ambipolar properties of PEI-doped n-type CNT TFTs fabricated on a transparent plastic film. We found that current collapse and hysteresis are predominantly caused by the combination of water and oxygen, suggesting that a water/oxygen redox reaction is responsible for the instability of PEI-doped devices. Water vapor has a rather more severe impact in the case of PEI-doped devices than in the case of undoped CNT TFTs because of the hygroscopicity of PEI. Surface passivation with Al2O3, deposited by a low-temperature atomic layer deposition technique, notably improved the stability of the device properties in ambient air.

  4. Take-off and propeller thrust

    NASA Technical Reports Server (NTRS)

    Schrenk, Martin

    1933-01-01

    As a result of previous reports, it was endeavored to obtain, along with the truest possible comprehension of the course of thrust, a complete, simple and clear formula for the whole take-off distance up to a certain altitude, which shall give the correct relative weight to all the factors.

  5. Early Cenozoic thrust in Qiangtang block, Northern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wu, Z.; Ye, P.; Hu, D.; Lu, L.; Zhang, Y.

    2011-12-01

    Huge thrust systems, North Qiangtang Thrust (NQT) and South Qiangtang Thrust (SQT), were discovered in Qiangtang block, northern Tibetan Plateau. North Qiangtang thrust (NQT), including Dogai Coren thrust (DCT) and Longwei Co Thrust (LCT) formed in northern Qiangtang block. Triassic shale, sandstone and slate were thrusted southward over Late Cretaceous-Early Cenozoic conglomerate and sandstone (simplified as red-beds) along thrust faults of DCT, and Jurassic limestone and sandstone were thrusted over Late Cretaceous-Paleogene red-beds and Paleozoic metamorphic rocks along thrust faults of LCT in north of Central Qiangtang Uplift (CQU). South Qiangtang Thrust (SQT), including Xiaocaka-Shuanghu thrust (XST), Doma-Qixiang Co thrust (DQT) and Saibu Co-Zagya thrust (SZT), formed in southern Qiangtang block, accompanied by Nima-Silin thrust (NST) in northern Lhasa block. Permian marbleized limestone and dolomite, Triassic sandstone and shale, Jurassic limestone and ophiolite were thrusted southward over Paleogene red-beds along thrust faults of XST, DQT and SZT. Early Cenozoic thrust along NQT and SQT formed variety of tectonic slices, outliers and nappes of Permian-Jurassic rocks overlying Late Cretaceous-Paleogene red-beds in northern, central and southern Qiangtang block. Minimal estimation on southward offsets of DCT and LCT is 25km and 50km respectively, corresponding to 43% shortening in northern Qiangtang block, and minimal estimation on southward thrust offsets of XST, DQT and SZT yields ~90km southward thrust displacement of SQT, corresponding to ~47% shortening in southern Qiangtang block. Major thrust faults of NQT and SQT formed in upper crust according to seismic reflection profile, and such thrust and shortening were geodynamically related to northward subduction of India continental plate. Intensive thrust of NQT and SQT stopped before Early Miocene, followed by regional peneplanation, widespread lacustrine deposits in Early Miocene and crust extension as

  6. Thrust Stand for Electric Propulsion Performance Evaluation

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Markusic, Thomas E.; Stanojev, Boris J.; Dehoyos, Amado; Spaun, Benjamin

    2006-01-01

    An electric propulsion thrust stand capable of supporting testing of thrusters having a total mass of up to 125 kg and producing thrust levels between 100 microN to 1 N has been developed and tested. The design features a conventional hanging pendulum arm attached to a balance mechanism that converts horizontal deflections produced by the operating thruster into amplified vertical motion of a secondary arm. The level of amplification is changed through adjustment of the location of one of the pivot points linking the system. Response of the system depends on the relative magnitudes of the restoring moments applied by the displaced thruster mass and the twisting torsional pivots connecting the members of the balance mechanism. Displacement is measured using a non-contact, optical linear gap displacement transducer and balance oscillatory motion is attenuated using a passive, eddy-current damper. The thrust stand employs an automated leveling and thermal control system. Pools of liquid gallium are used to deliver power to the thruster without using solid wire connections, which can exert undesirable time-varying forces on the balance. These systems serve to eliminate sources of zero-drift that can occur as the stand thermally or mechanically shifts during the course of an experiment. An in-situ calibration rig allows for steady-state calibration before, during and after thruster operation. Thrust measurements were carried out on a cylindrical Hall thruster that produces mN-level thrust. The measurements were very repeatable, producing results that compare favorably with previously published performance data, but with considerably smaller uncertainty.

  7. Performance of 4600-pound-thrust centrifugal-flow-type turbojet engine with water-alcohol injection at inlet

    NASA Technical Reports Server (NTRS)

    Glasser, Philip W

    1950-01-01

    An experimental investigation of the effects of injecting a water-alcohol mixture of 2:1 at the compressor inlet of a centrifugal-flow type turbojet engine was conducted in an altitude test chamber at static sea-level conditions and at an altitude of 20,000 feet with a flight Mach number of 0.78 with an engine operating at rated speed. The net thrust was augmented by 0.16 for both flight conditions with a ratio of injected liquid to air flow of 0.05. Further increases in the liquid-air ratio did not give comparable increases in thrust.

  8. Direct thrust measurement of a 30-cm ion thruster

    NASA Technical Reports Server (NTRS)

    Banks, B.; Rawlin, V.; Weigand, A.; Walker, J.

    1975-01-01

    A direct thrust measurement of a 30-cm diameter ion thruster was accomplished by means of a laser interferometer thrust stand. The thruster was supported in a pendulum manner by three 3.65-m long wires. Electrical power was provided by means of 18 mercury filled pots. A movable 23-button planar probe rake was used to determine thrust loss due to ion beam divergence. Values of thrust, thrust loss due to ion beam divergence, and thrust loss due to multiple ionization were measured for ion beam currents ranging from 0.5 to 2.5 A. Measured thrust values indicate an accuracy of approximately 1% and are in good agreement with thrust values calculated by indirect measurements.

  9. Direct thrust measurement of a 30-cm ion thruster

    NASA Technical Reports Server (NTRS)

    Banks, B.; Rawlin, V.; Weigand, A. J.; Walker, J.

    1975-01-01

    A direct thrust measurement of a 30-cm diameter ion thruster was accomplished by means of a laser interferometer thrust stand. The thruster was supported in a pendulum manner by three 3.65-m long wires. Electrical power was provided by means of 18 mercury filled pots. A movable 23-button planar probe rake was used to determine thrust loss due to ion beam divergence. Values of thrust, thrust loss due to ion beam divergence, and thrust loss due to multiple ionization were measured for ion beam currents ranging from 0.5 A to 2.5 A. Measured thrust values indicate an accuracy of approximately 1% and are in good agreement with thrust values calculated by indirect measurements.

  10. Study on development of ejector of Bubble Jet Engine (BJE) - measurement of thrust -

    NASA Astrophysics Data System (ADS)

    Ono, B.; Nakashima, K.; Shigematsu, T.; Morishita, K.

    2009-02-01

    The AUV (Autonomous Under-water Vehicle), which is used for the present seabed investigations, has obtained the thrust with the screw driven by the battery. However, it has a disadvantage because of its size and cost. Therefore, this research is carried out to propose the Bubble Jet Engine (BJE) as an alternative propulsion device. It can directly transform combustion energy into kinetic energy, so it is expected that BJE can also rise the level of propulsion efficiency. This research aims at measuring exhaled mass flow rate and thrust to design ejectors, which become the core of BJE, and exploring practical possibility of BJE. Vertical type gas-water ejector experimental apparatus for measuring water entrainment was employed in order to understand the characteristics of operation conditions, such as inlet distance, air pressure of nozzle, diameter of nozzle, and so on. In addition, experiments for measuring the thrust in the condition of ejector were executed with horizontal type apparatus in water. However, the influence of the ejector to improve thrust can't have been recognized with high-pressure air at room temperature yet.

  11. Thrusting and gravel progradation in foreland basins: A test of post-thrusting gravel dispersal

    SciTech Connect

    Burbank, D.W.; Beck, R.A.; Hobbs, R. ); Raynolds, R.G.H. ); Tahirkheli, R.A.K. )

    1988-12-01

    The use of gravels as syntectonic indicators of thrusting has recently been questioned by foreland-basin models that assign gravels to a post-thrusting interval of progradation, except in very proximal areas. On the basis of precise temporal control provided by magnetostratigraphically dated sections, the history of gravel progradation after a major thrusting and uplift event in the northwestern Himalaya is shown to be a virtually syntectonic phenomenon. Despite considerable crustal subsidence driven by a thick-skinned thrust, gravels prograded {approximately} 70 km during a 1.5-m.y.-long thrusting event. By 3 m.y. after the start of thrusting, gravels extended more than 110 km into the basin. Although delayed gravel progradation appears appropriate for many Rocky Mountain foreland basins, it is clearly not valid for the Himalaya. The authors attribute the difference in depositional response between these basins to difference in the quantity of sediment supplied to them (sediment starved vs. overfilled), the availability of resistates in the source area, and the size of the antecedent drainage.

  12. A workflow for 3D model building in fold-thrust belts

    NASA Astrophysics Data System (ADS)

    Watkins, Hannah; Bond, Clare; Butler, Rob

    2016-04-01

    3D geological models can be used in fold-thrust belts for many purposes such as analysing geometric variation in folds, kinematic modelling to restore fold surfaces, generating strain distribution maps and predicting fracture network distribution. We present a workflow for 3D model building using outcrop bedding data, geological maps, Digital Terrain Models (DTM's), air photos and field photographs. We discuss the challenges of software limitations for 3D kinematic restoration and forward modelling in fold-thrust belt settings. We then discuss the sensitivity of model building approaches to the application of 3D geological models in fold-thrust belts for further analysis e.g. changes in along strike fold geometry, restoration using kinematic and geomechanical modelling, strain prediction and Discrete Fracture Network (DFN) modelling. To create 3D models geological maps and bedding data are digitised using Move software; digitised maps and data are then draped onto DTM's. A series of closely spaced cross section lines are selected; the orientation of these is calculated by determining the average orientation of bedding dip direction. Fault and horizon line intersections, along with bedding data from within a narrow margin of the section lines are projected onto each cross section. Field photographs and sketches are integrated into the cross sections to determine thrust angles at the surface. Horizon lines are then constructed using bedding data. Displacement profiles for thrusts are plotted to ensure thrust displacements are valid with respect to neighbouring cross section interpretations; any discrepancies are alleviated by making minor adjustments to horizon and thrust lines, while ensuring that resultant cross section geometries still adhere to bedding data and other field observations. Once the cross sections have been finalised, 3D surfaces are created using the horizon and thrust line interpretations on each cross section. The simple curvature of 3D surfaces

  13. Thrust measurements of a hollow-cathode discharge

    NASA Technical Reports Server (NTRS)

    Snyder, A.; Banks, B. A.

    1972-01-01

    Thrust measurements of a hollow cathode mercury discharge were made with a synthetic mica target on a torsion pendulum. Thrust measurements were made for various target angles, tip temperatures, flow rates, keeper discharge powers, and accelerator electrode voltages. The experimental thrust data are compared with theoretical values for the case where no discharge power was employed.

  14. Thrust and Propulsive Efficiency from an Instructive Viewpoint

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2010-01-01

    In a typical engineering or physics curriculum, the momentum equation is used for the determination of jet engine thrust. Even a simple thrust analysis requires a heavy emphasis on mathematics that can cause students and engineers to lose a physical perspective on thrust. This article provides for this physical understanding using only static…

  15. Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate

    PubMed Central

    Reed, William R.; Cao, Dong-Yuan; Long, Cynthia R.; Kawchuk, Gregory N.; Pickar, Joel G.

    2013-01-01

    High velocity low amplitude spinal manipulation (HVLA-SM) is used frequently to treat musculoskeletal complaints. Little is known about the intervention's biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150 ms suggesting the presence of a threshold value. Thrust velocities greater than 20–30 mm/s and thrust rates greater than 300 N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages. PMID:23401713

  16. Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate.

    PubMed

    Reed, William R; Cao, Dong-Yuan; Long, Cynthia R; Kawchuk, Gregory N; Pickar, Joel G

    2013-01-01

    High velocity low amplitude spinal manipulation (HVLA-SM) is used frequently to treat musculoskeletal complaints. Little is known about the intervention's biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150 ms suggesting the presence of a threshold value. Thrust velocities greater than 20-30 mm/s and thrust rates greater than 300 N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages.

  17. 14 CFR 33.79 - Fuel burning thrust augmentor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel burning thrust augmentor. 33.79... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.79 Fuel burning thrust augmentor. Each fuel burning thrust augmentor, including the nozzle, must— (a) Provide cutoff...

  18. Pressure-loss and flow coefficients inside a chordwise-finned, impingement, convection, and film air-cooled turbine vane

    NASA Technical Reports Server (NTRS)

    Hippensteele, S. A.

    1974-01-01

    Total-pressure-loss coefficients, flow discharge coefficients, and friction factors were determined experimentally for the various area and geometry changes and flow passages within an air-cooled turbine vane. The results are compared with those of others obtained on similar configurations, both actual and large models, of vane passages. The supply and exit air pressures were controlled and varied. The investigation was conducted with essentially ambient-temperature air and without external flow of air over the vane.

  19. Bio-inspired fabrication of hierarchical FeOOH nanostructure array films at the air-water interface, their hydrophobicity and application for water treatment.

    PubMed

    Liu, Lei; Yang, Liu-Qing; Liang, Hai-Wei; Cong, Huai-Ping; Jiang, Jun; Yu, Shu-Hong

    2013-02-26

    Hierarchical FeOOH nanostructure array films constructed by different nanosized building blocks can be synthesized at the air-water interface via a bio-inspired gas-liquid diffusion method. In this approach, poly(acrylic acid) (PAA) as a crystal growth modifier plays a crucial role in mediating the morphology and polymorph of FeOOH crystals. With the increase of PAA concentration, the shape of the building blocks assembling into FeOOH films can be tailored from nanosheets, to rice spikes, then to branched fibers, and finally to nanowires. What is more, a low concentration of PAA will induce the formation of α-FeOOH, while a high one could stabilize FeOOH in the form of the γ-FeOOH phase. After being modified with a thin layer of polydimethylsiloxane (PDMS), the as-prepared FeOOH films exhibited strong hydrophobicity with water contact angles (CA) from 134° to 148° or even superhydrophobicity with a CA of 164° in the sample constructed by nanosheets. When the FeOOH nanostructures were dispersed in water by ultrasound, they displayed quite promising adsorption performance of heavy metal ions for water treatment, where the highest adsorption capacity can reach 77.2 mg·g⁻¹ in the sample constructed by nanowires. This bio-inspired approach may open up the possibilities for the fabrication of other functional nanostructure thin films with unique properties.

  20. NATURAL BARRIERS TARGETED THRUST FY 2004 PROJECTS

    SciTech Connect

    NA

    2005-07-27

    This booklet contains project descriptions of work performed by the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology and International's (OST&I) Natural Barriers Targeted Thrust during Fiscal Year (FY) 2004. The Natural Barriers Targeted Thrust is part of OST&I's Science and Technology Program which supports the OCRWM mission to manage and dispose of high-level radioactive waste and spent nuclear fuel in a manner that protects health, safety, and the environment; enhances national and energy security; and merits public confidence. In general, the projects described will continue beyond FY 2004 assuming that the technical work remains relevant to the proposed Yucca Mountain Repository and sufficient funding is made available to the Science and Technology Program.

  1. Thrust improvement with ablative insert nozzle extension

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.; Back, L. H.

    1986-01-01

    Aspects are examined of an investigation by the Marshall Space Flight Center into the conceptual feasibility of increasing the thrust performance of the Space Shuttle Main Engine (SSME) by using a conical nozzle extension fitted with an ablative insert in order to achieve a low-cost, near-term gain in payload. The ablating insert would provide a controlled increase in nozzle expansion ratio during launch and early climbout (first 30-60 seconds) so as to reduce thrust loss from nozzle over-expansion in the lower atmosphere. Summaries are given of JPL studies in the area of: defining the near-wall flow environment in the extended nozzle insert region; selecting potential insert materials; conceptualizing an extension/insert geometrical configuration; and identifying future experimental efforts necessary to verify the feasibility of the concepts.

  2. MATERIALS PERFORMANCE TARGETED THRUST FY 2004 PROJECTS

    SciTech Connect

    DOE

    2005-09-13

    The Yucca Mountain site was recommended by the President to be a geological repository for commercial spent nuclear fuel and high-level radioactive waste. The multi-barrier approach was adopted for assessing and predicting system behavior, including both natural barriers and engineered barriers. A major component of the long-term strategy for safe disposal of nuclear waste is first to completely isolate the radionuclides in waste packages for long times and then to greatly retard the egress and transport of radionuclides from penetrated packages. The goal of the Materials Performance Targeted Thrust program is to further enhance the understanding of the role of engineered barriers in waste isolation. In addition, the Thrust will explore technical enhancements and seek to offer improvements in materials costs and reliability.

  3. High temperature thrust chamber for spacecraft

    NASA Technical Reports Server (NTRS)

    Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

    1998-01-01

    A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

  4. Electromechanical actuator for thrust vector control

    NASA Astrophysics Data System (ADS)

    Zubkow, Zygmunt

    Attention is given to the development and testing of electromechanical actuator (EMA) systems for use in first- and second-stage thrust vector control of rocket engines. An overview of the test program is also presented. Designs for both first- and second-stage actuators employ redundant dc brushless, three-phase rare-earth permanent magnet motors. The first-stage actuator is about 28 hp per motor and uses a roller screw. Second-stage thrust vector control is implemented with a much smaller actuator of about 1 hp per motor. This actuator uses a gear drive with a recycling ball screw mechanism. An operational EMA is presented. This 6.5-in. actuator is capable of a stall force of 1350 pounds per motor and a frequency response of about 5 HZ.

  5. Thrust production by a mechanical swimming lamprey

    NASA Astrophysics Data System (ADS)

    Leftwich, M. C.; Smits, A. J.

    2011-05-01

    To develop a comprehensive model of lamprey locomotion, we use a robotic lamprey to investigate the formation of the wake structure, the shedding vorticity from the body, and the relationship between thrust production and pressure on the surface of the robot. The robot mimics the motion of living lamprey in steady swimming by using a programmable microcomputer to actuate 13 servomotors that produce a traveling wave along the length of the lamprey body. The amplitude of the phase-averaged surface pressure distribution along the centerline of the robot increases toward the tail, which is consistent with previous momentum balance experiments. This indicates that thrust is produced mainly at the tail. The phase relationship between the pressure signal and the vortex shedding from the tail is also examined, showing a clear connection between the location of vortex structures and the fluctuations of the pressure signal.

  6. Low-thrust Isp sensitivity study

    NASA Technical Reports Server (NTRS)

    Schoenman, L.

    1982-01-01

    A comparison of the cooling requirements and attainable specific impulse performance of engines in the 445 to 4448N thrust class utilizing LOX/RP-1, LOX/Hydrogen and LOX/Methane propellants is presented. The unique design requirements for the regenerative cooling of low-thrust engines operating at high pressures (up to 6894 kPa) were explored analytically by comparing single cooling with the fuel and the oxidizer, and dual cooling with both the fuel and the oxidizer. The effects of coolant channel geometry, chamber length, and contraction ratio on the ability to provide proper cooling were evaluated, as was the resulting specific impulse. The results show that larger contraction ratios and smaller channels are highly desirable for certain propellant combinations.

  7. CFD Code Survey for Thrust Chamber Application

    NASA Technical Reports Server (NTRS)

    Gross, Klaus W.

    1990-01-01

    In the quest fo find analytical reference codes, responses from a questionnaire are presented which portray the current computational fluid dynamics (CFD) program status and capability at various organizations, characterizing liquid rocket thrust chamber flow fields. Sample cases are identified to examine the ability, operational condition, and accuracy of the codes. To select the best suited programs for accelerated improvements, evaluation criteria are being proposed.

  8. Lightweight Chambers for Thrust Cell Applications

    NASA Technical Reports Server (NTRS)

    Elam, S.; Effinger, M.; Holmes, R.; Lee, J.; Jaskowiak, M.

    2000-01-01

    Traditional metals like steel and copper alloys have been used for many years to fabricate injector and chamber components of thruster assemblies. While the materials perform well, reducing engine weights would help existing and future vehicles gain performance and payload capability. It may now be possible to reduce current thruster weights up to 50% by applying composite materials. In this task, these materials are being applied to an existing thrust cell design to demonstrate new fabrication processes and potential weight savings. Two ceramic matrix composite (CMC) designs, three polymer matrix composite (PMC) designs, and two metal matrix composite (MMC) designs are being fabricated as small chamber demonstration units. In addition, a new alloy of copper, chrome, and niobium (Cu-8Cr-4Nb) is being investigated for thrust chamber liners since it offers higher strength and increased cycle life over traditional alloys. This new alloy is being used for the liner in each MMC and PMC demonstration unit. During June-August of 2000, hot-fire testing of each unit is planned to validate designs in an oxygen/hydrogen environment at chamber pressures around 850 psi. Although the weight savings using CMC materials is expected to be high, they have proven to be much harder to incorporate into chamber designs based on current fabrication efforts. However, the PMC & MMC concepts using the Cu-8Cr-4Nb liner are nearly complete and ready for testing. Additional efforts intend to use the PMC & MMC materials to fabricate a full size thrust chamber (60K lb(sub f) thrust class). The fabrication of this full size unit is expected to be complete by October 2000, followed by hot-fire testing in November-December 2000.

  9. Low Carbon Propulsion Strategic Thrust Overview

    NASA Technical Reports Server (NTRS)

    Dryer, Jay

    2014-01-01

    NASA is taking a leadership role with regard to developing new options for low-carbon propulsion. Work related to the characterization of alternative fuels is coordinated with our partners in government and industry, and NASA is close to concluding a TC in this area. Research on alternate propulsion concepts continues to grow and is an important aspect of the ARMD portfolio. Strong partnerships have been a key enabling factor for research on this strategic thrust.

  10. The thrust belts of Western North America

    SciTech Connect

    Moulton, F.C.

    1993-08-01

    Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

  11. Development of sputtered techniques for thrust chambers

    NASA Technical Reports Server (NTRS)

    Mullaly, J. R.; Hecht, R. J.; Schmid, T. E.; Torrey, C. T.

    1975-01-01

    Techniques and materials were developed and evaluated for the fabrication and coating of advanced, long life, regeneratively cooled thrust chambers. Materials were analyzed as fillers for sputter application of OFHC copper as a closeout layer to channeled inner structures; of the materials evaluated, aluminum was found to provide the highest bond strength and to be the most desirable for chamber fabrication. The structures and properties were investigated of thick sputtered OFHC copper, 0.15 Zr-Cu, Al2O3,-Cu, and SiC-Cu. Layered structures of OFHC copper and 0.15 Zr-Cu were investigated as means of improving chamber inner wall fatigue life. The evaluation of sputtered Ti-5Al-2.5Sn, NASA IIb-11, aluminum and Al2O3-Al alloys as high strength chamber outer jackets was performed. Techniques for refurbishing degraded thrust chambers with OFHC copper and coating thrust chambers with protective ZrO2 and graded ZrO2-copper thermal barrier coatings were developed.

  12. Thrust and power measurements of Olympic swimmers

    NASA Astrophysics Data System (ADS)

    Wei, Timothy; Wu, Vicki; Hutchison, Sean; Mark, Russell

    2012-11-01

    Elite level swimming is an extremely precise and even choreographed activity. Swimmers not only know the exact number of strokes necessary to take them across the pool, they also plan to be a precise distance from the wall at the end of their last stroke. Too far away and they lose time by drifting into the wall. Too close and their competitor may slide in before their hand comes forward to touch the wall. In this context, it is important to know, in detail, where and how a swimmer propels her/himself through the water. Over the past decade, state-of-the-art flow and thrust measurement diagnostics have been brought to competitive swimming. But the ability to correlate stroke mechanics to thrust production without somehow constraining the swimmer has here-to-fore not been possible. Using high speed video, a simple approach to mapping the swimmer's speed, thrust and net power output in a time resolved manner has been developed. This methodology has been applied to Megan Jendrick, gold medalist in the 100 individual breast stroke and 4 × 100 medley relay events in 2000 and Ariana Kukors, 2009 world champion and continuing world record holder in the 200 individual medley. Implications for training future elite swimmers will be discussed.

  13. Thrust Vector Control for Nuclear Thermal Rockets

    NASA Technical Reports Server (NTRS)

    Ensworth, Clinton B. F.

    2013-01-01

    Future space missions may use Nuclear Thermal Rocket (NTR) stages for human and cargo missions to Mars and other destinations. The vehicles are likely to require engine thrust vector control (TVC) to maintain desired flight trajectories. This paper explores requirements and concepts for TVC systems for representative NTR missions. Requirements for TVC systems were derived using 6 degree-of-freedom models of NTR vehicles. Various flight scenarios were evaluated to determine vehicle attitude control needs and to determine the applicability of TVC. Outputs from the models yielded key characteristics including engine gimbal angles, gimbal rates and gimbal actuator power. Additional factors such as engine thrust variability and engine thrust alignment errors were examined for impacts to gimbal requirements. Various technologies are surveyed for TVC systems for the NTR applications. A key factor in technology selection is the unique radiation environment present in NTR stages. Other considerations including mission duration and thermal environments influence the selection of optimal TVC technologies. Candidate technologies are compared to see which technologies, or combinations of technologies best fit the requirements for selected NTR missions. Representative TVC systems are proposed and key properties such as mass and power requirements are defined. The outputs from this effort can be used to refine NTR system sizing models, providing higher fidelity definition for TVC systems for future studies.

  14. Nozzle Thrust Optimization While Reducing Jet Noise

    NASA Technical Reports Server (NTRS)

    Seiner, J. M.; Gilinsky, M. M.

    1995-01-01

    A Bluebell nozzle design concept is proposed for jet noise reduction with minimal thrust loss or even thrust augmentation. A Bluebell nozzle has a sinusoidal lip line edge (chevrons) and a sinusoidal cross section shape with linear amplitude increasing downstream in the divergent nozzle part (corrugations). The experimental tests of several Bluebell nozzle designs have shown nose reduction relative to a convergent-divergent round nozzle with design exhaust number M(e) = 1.5. The best design provides an acoustic benefit near 4dB with about 1 percent thrust augmentation. For subsonic flow ((M(e)= 0.6)), the tests indicated that the present method for design of Bluebell nozzles gives less acoustic benefit and in most cases jet noise increased. The proposed designs incorporate analytical theory and 2D and 3D numerical simulations. Full Navier-Stokes and Euler solvers were utilized. Boundary layer effects were used. Several different designs were accounted for in the Euler applications.

  15. Evolutionary Computing for Low-thrust Navigation

    NASA Technical Reports Server (NTRS)

    Lee, Seungwon; Fink, Wolfgang; vonAllmed, Paul; Petropoulos, Anastassios E.; Russell, Ryan P.; Terrile, Richard J.

    2005-01-01

    The development of new mission concepts requires efficient methodologies to analyze, design and simulate the concepts before implementation. New mission concepts are increasingly considering the use of ion thrusters for fuel-efficient navigation in deep space. This paper presents parallel, evolutionary computing methods to design trajectories of spacecraft propelled by ion thrusters and to assess the trade-off between delivered payload mass and required flight time. The developed methods utilize a distributed computing environment in order to speed up computation, and use evolutionary algorithms to find globally Pareto-optimal solutions. The methods are coupled with two main traditional trajectory design approaches, which are called direct and indirect. In the direct approach, thrust control is discretized in either arc time or arc length, and the resulting discrete thrust vectors are optimized. In the indirect approach, a thrust control problem is transformed into a costate control problem, and the initial values of the costate vector are optimized. The developed methods are applied to two problems: 1) an orbit transfer around the Earth and 2) a transfer between two distance retrograde orbits around Europa, the closest to Jupiter of the icy Galilean moons. The optimal solutions found with the present methods are comparable to other state-of-the-art trajectory optimizers and to analytical approximations for optimal transfers, while the required computational time is several orders of magnitude shorter than other optimizers thanks to an intelligent design of control vector discretization, advanced algorithmic parameterization, and parallel computing.

  16. Polysaccharide films at an air/liquid and a liquid/silicon interface: effect of the polysaccharide and liquid type on their physical properties.

    PubMed

    Taira, Yasunori; McNamee, Cathy E

    2014-11-14

    We investigated the effect of the polysaccharide type, the subphase on which the Langmuir monolayers were prepared, and the liquid in which the properties of the transferred monolayers were measured on the physical properties of the polysaccharide films at an air/aqueous interface and at a silicon substrate, and the forces and friction of the polysaccharide transferred films when measured in solution against a silica probe. Chitosan was modified with a silane coupling agent to make chitosan derived compounds with a low and a medium molecular weight. Chitin and the chitosan-derived compounds were used to make Langmuir monolayers at air/water and air/pH 9 buffer interfaces. The monolayers were transferred to silicon substrates via Langmuir-Blodgett deposition, and the chitosan-derived compounds subsequently chemically reacted with the silicon substrates. Atomic force microscope force and friction measurements were made in water and in the pH 9 buffer, where the water and the pH 9 buffer acted as a good and a bad solvent for the polysaccharides, respectively. The polysaccharide type affected the friction of the polysaccharide film, where the physically adsorbed chitin gave the lowest friction. The friction of L-chitosan was higher than that of M-chitosan in water, suggesting that the molecular weight of the polymer affects its lubricating ability. The forces and friction of the polysaccharide films changed when the subphase on which the Langmuir monolayers were formed was changed or when the liquid in which the properties of the films adsorbed at the silicon substrate were measured was changed. The friction increased significantly when the liquid was changed from water to the pH 9 buffer. This increase was explained by the reduced charge of the chitin and chitosan-derived materials due to the pH increase, the screening of the charges by the salts in the buffer, and the possible hardening of the monolayer caused by the adsorption of salts from the buffer. PMID:25248865

  17. Polysaccharide films at an air/liquid and a liquid/silicon interface: effect of the polysaccharide and liquid type on their physical properties.

    PubMed

    Taira, Yasunori; McNamee, Cathy E

    2014-11-14

    We investigated the effect of the polysaccharide type, the subphase on which the Langmuir monolayers were prepared, and the liquid in which the properties of the transferred monolayers were measured on the physical properties of the polysaccharide films at an air/aqueous interface and at a silicon substrate, and the forces and friction of the polysaccharide transferred films when measured in solution against a silica probe. Chitosan was modified with a silane coupling agent to make chitosan derived compounds with a low and a medium molecular weight. Chitin and the chitosan-derived compounds were used to make Langmuir monolayers at air/water and air/pH 9 buffer interfaces. The monolayers were transferred to silicon substrates via Langmuir-Blodgett deposition, and the chitosan-derived compounds subsequently chemically reacted with the silicon substrates. Atomic force microscope force and friction measurements were made in water and in the pH 9 buffer, where the water and the pH 9 buffer acted as a good and a bad solvent for the polysaccharides, respectively. The polysaccharide type affected the friction of the polysaccharide film, where the physically adsorbed chitin gave the lowest friction. The friction of L-chitosan was higher than that of M-chitosan in water, suggesting that the molecular weight of the polymer affects its lubricating ability. The forces and friction of the polysaccharide films changed when the subphase on which the Langmuir monolayers were formed was changed or when the liquid in which the properties of the films adsorbed at the silicon substrate were measured was changed. The friction increased significantly when the liquid was changed from water to the pH 9 buffer. This increase was explained by the reduced charge of the chitin and chitosan-derived materials due to the pH increase, the screening of the charges by the salts in the buffer, and the possible hardening of the monolayer caused by the adsorption of salts from the buffer.

  18. Initiation process of a thrust fault revealed by analog experiments

    NASA Astrophysics Data System (ADS)

    Yamada, Yasuhiro; Dotare, Tatsuya; Adam, Juergen; Hori, Takane; Sakaguchi, Hide

    2016-04-01

    We conducted 2D (cross-sectional) analog experiments with dry sand using a high resolution digital image correlation (DIC) technique to reveal initiation process of a thrust fault in detail, and identified a number of "weak shear bands" and minor uplift prior to the thrust initiation. The observations suggest that the process can be divided into three stages. Stage 1: characterized by a series of abrupt and short-lived weak shear bands at the location where the thrust will be generated later. Before initiation of the fault, the area to be the hanging wall starts to uplift. Stage 2: defined by the generation of the new thrust and its active displacement. The location of the new thrust seems to be constrained by its associated back-thrust, produced at the foot of the surface slope (by the previous thrust). The activity of the previous thrust turns to zero once the new thrust is generated, but the timing of these two events is not the same. Stage 3: characterized by a constant displacement along the (new) thrust. Similar minor shear bands can be seen in the toe area of the Nankai accretionary prism, SW Japan and we can correlate the along-strike variations in seismic profiles to the model results that show the characteristic features in each thrust development stage.

  19. A Layman's Guide to Thrust Engine Development for Super/Hyper Sonic Flight.

    ERIC Educational Resources Information Center

    Thiesse, James L.

    The intention of this paper is to discuss the advances in thrust engines from the initial development of the J58/SR-71 (JT11D-20) of the U.S. Air Force's SR-71 Blackbird to the development of the RAM and SCRAM engines necessary to propel the new generations of high-flying super-speed aircraft. Engineering complexities suggest that the engines and…

  20. Aroma sensing and indoor air monitoring by quartz crystal resonators with sensory films prepared by sputtering of biomaterials and sintered polymers.

    PubMed

    Seyama, Michiko; Sugimoto, Iwao; Nakamura, Masayuki

    2004-11-01

    Thickness shear mode quartz-crystal resonator coated with plasma polymer films (PPFs) produced by radio-frequency sputtering of biomaterials and synthetic polymers were examined with respect to their abilities to continuously monitor indoor air. We confirmed the sensory capabilities of an array of PPF sensors to aromas emitted from essential oils at concentrations as low as the detection threshold of human olfaction. Changes in humidity induced a drift in the response curves of PPF sensors. On the contrary, volatile compounds exhibited pulse signals. The pulse signals of a D-phenylalanine sensor and a polyethylene sensor were synchronous, but the direction of the peaks was inverted in most cases. Compared with a photo-ionization detector sensor, the PPF sensors were able to detect subtle changes in the concentrations of volatile compounds in indoor air.

  1. Static investigation of a two-dimensional convergent-divergent exhaust nozzle with multiaxis thrust-vectoring capability

    NASA Technical Reports Server (NTRS)

    Taylor, John G.

    1990-01-01

    An investigation was conducted in the Static Test Facility of the NASA Langley 16-Foot Transonic Tunnel to determine the internal performance of two-dimensional convergent-divergent nozzles designed to have simultaneous pitch and yaw thrust vectoring capability. This concept utilized divergent flap rotation of thrust vectoring in the pitch plane and deflection of flat yaw flaps hinged at the end of the sidewalls for yaw thrust vectoring. The hinge location of the yaw flaps was varied at four positions from the nozzle exit plane to the throat plane. The yaw flaps were designed to contain the flow laterally independent of power setting. In order to eliminate any physical interference between the yaw flap deflected into the exhaust stream and the divergent flaps, the downstream corners of both upper and lower divergent flaps were cut off to allow for up to 30 deg of yaw flap deflection. The impact of varying the nozzle pitch vector angle, throat area, yaw flap hinge location, yaw flap length, and yaw flap deflection angle on nozzle internal performance characteristics, was studied. High-pressure air was used to simulate jet exhaust at nozzle pressure ratios up to 7.0. Static results indicate that configurations with the yaw flap hinge located upstream of the exit plane provide relatively high levels of thrust vectoring efficiency without causing large losses in resultant thrust ratio. Therefore, these configurations represent a viable concept for providing simultaneous pitch and yaw thrust vectoring.

  2. Extended performance solar electric propulsion thrust system study. Volume 2: Baseline thrust system

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.; Hawthorne, E. I.

    1977-01-01

    Several thrust system design concepts were evaluated and compared using the specifications of the most advanced 30- cm engineering model thruster as the technology base. Emphasis was placed on relatively high-power missions (60 to 100 kW) such as a Halley's comet rendezvous. The extensions in thruster performance required for the Halley's comet mission were defined and alternative thrust system concepts were designed in sufficient detail for comparing mass, efficiency, reliability, structure, and thermal characteristics. Confirmation testing and analysis of thruster and power-processing components were performed, and the feasibility of satisfying extended performance requirements was verified. A baseline design was selected from the alternatives considered, and the design analysis and documentation were refined. The baseline thrust system design features modular construction, conventional power processing, and a concentractor solar array concept and is designed to interface with the space shuttle.

  3. Stress, strain, and fault behavior at a thrust ramp: Insights from the Naukluft thrust, Namibia

    NASA Astrophysics Data System (ADS)

    Fagereng, Åke; Smith, Zach; Rowe, Christie D.; Makhubu, Bandile; Sylvester, Fernando Y. G.

    2014-01-01

    We report observations from a kilometer-scale thrust ramp on the Naukluft thrust, Namibia. The Naukluft thrust is a low angle thrust that was active at subgreenschist facies conditions and accommodated several tens of kilometers of displacement at the base of the Naukluft Nappe Complex in the Pan-African Damara Orogeny. The fault zone is generally planar and a few meters thick, comprising predominantly a dolomite-rich cataclasite. At the ramp, the fault-rock assemblage increases in thickness, and the hanging-wall, which elsewhere is relatively intact, contains a high density network of inclined quartz veins, subvertical dolomite and calcite veins, breccia zones, as well as injectites of cataclastic fault rock emanating from the fault surface. The geometry of the hanging-wall structures indicates local subhorizontal extension. Local tensile stress can be explained by bending in the hanging-wall as it deformed to slide above the ramp structure. High fluid pressures created dynamically during fast slip by decarbonation of carbonate fault rock, and by dewatering of the footwall under an impermeable fault during interseismic periods, led to additional reduction in local effective compressive stresses. In this location, the ramp is more optimally oriented for slip in the inferred regional stress field, and therefore likely to fail before the contiguous thrust flats that are subparallel to the maximum principal stress. As such, the ramp represents the likely location for nucleation of fault slip, which could both trigger dynamic failure of the adjacent thrust faults, and produce hanging-wall extensional structures.

  4. Analysis of gas turbine engines using water and oxygen injection to achieve high Mach numbers and high thrust

    NASA Technical Reports Server (NTRS)

    Henneberry, Hugh M.; Snyder, Christopher A.

    1993-01-01

    An analysis of gas turbine engines using water and oxygen injection to enhance performance by increasing Mach number capability and by increasing thrust is described. The liquids are injected, either separately or together, into the subsonic diffuser ahead of the engine compressor. A turbojet engine and a mixed-flow turbofan engine (MFTF) are examined, and in pursuit of maximum thrust, both engines are fitted with afterburners. The results indicate that water injection alone can extend the performance envelope of both engine types by one and one-half Mach numbers at which point water-air ratios reach 17 or 18 percent and liquid specific impulse is reduced to some 390 to 470 seconds, a level about equal to the impulse of a high energy rocket engine. The envelope can be further extended, but only with increasing sacrifices in liquid specific impulse. Oxygen-airflow ratios as high as 15 percent were investigated for increasing thrust. Using 15 percent oxygen in combination with water injection at high supersonic Mach numbers resulted in thrust augmentation as high as 76 percent without any significant decrease in liquid specific impulse. The stoichiometric afterburner exit temperature increased with increasing oxygen flow, reaching 4822 deg R in the turbojet engine at a Mach number of 3.5. At the transonic Mach number of 0.95 where no water injection is needed, an oxygen-air ratio of 15 percent increased thrust by some 55 percent in both engines, along with a decrease in liquid specific impulse of 62 percent. Afterburner temperature was approximately 4700 deg R at this high thrust condition. Water and/or oxygen injection are simple and straightforward strategies to improve engine performance and they will add little to engine weight. However, if large Mach number and thrust increases are required, liquid flows become significant, so that operation at these conditions will necessarily be of short duration.

  5. Thrust measurements and flow field analysis of a piezoelectrically actuated oscillating cantilever

    NASA Astrophysics Data System (ADS)

    Eastman, Andrew; Kiefer, Jacob; Kimber, Mark

    2012-11-01

    Although not identical to the motion employed by nature's swimmers and flyers, the simple harmonic oscillations of cantilever-like structures have been shown to provide efficient low-power solutions for applications ranging from thermal management to propulsion. However, in order to quantify their true potential, the resulting flow field and corresponding thrust must be better understood. In this work, a thin, flexible cantilever is actuated via a piezoelectric patch mounted near its base and caused to vibrate in its first resonance mode in air. The flow field is experimentally measured with particle image velocimetry while the thrust produced from the oscillatory motion is quantified using a high-resolution scale. The trends observed in the data are captured using an oscillating Reynolds number, and a clear relationship is defined between the operating parameters and the resulting thrust. Two-dimensional flow fields are extracted from the x- y and y- z planes and are primarily used to motivate future geometry and sidewall configurations that could greatly enhance the thrust capabilities of the cantilever by directing the flow downstream in a more effective manner.

  6. Pressure and Thrust Measurements of a High-Frequency Pulsed-Detonation Actuator

    NASA Technical Reports Server (NTRS)

    Nguyen, Namtran C.; Cutler, Andrew D.

    2008-01-01

    This paper describes the development of a small-scale, high-frequency pulsed detonation actuator. The device utilized a fuel mixture of H2 and air, which was injected into the device at frequencies of up to 1200 Hz. Pulsed detonations were demonstrated in an 8-inch long combustion volume, at approx.600 Hz, for the lambda/4 mode. The primary objective of this experiment was to measure the generated thrust. A mean value of thrust was measured up to 6.0 lb, corresponding to specific impulse of 2611 s. This value is comparable to other H2-fueled pulsed detonation engines (PDEs) experiments. The injection and detonation frequency for this new experimental case was approx.600 Hz, and was much higher than typical PDEs, where frequencies are usually less than 100 Hz. The compact size of the model and high frequency of detonation yields a thrust-per-unit-volume of approximately 2.0 lb/cu in, and compares favorably with other experiments, which typically have thrust-per-unit-volume values of approximately 0.01 lb/cu in.

  7. Pressure and Thrust Measurements of a High-Frequency Pulsed Detonation Tube

    NASA Technical Reports Server (NTRS)

    Nguyen, N.; Cutler, A. D.

    2008-01-01

    This paper describes measurements of a small-scale, high-frequency pulsed detonation tube. The device utilized a mixture of H2 fuel and air, which was injected into the device at frequencies of up to 1200 Hz. Pulsed detonations were demonstrated in an 8-inch long combustion volume, at about 600 Hz, for the quarter wave mode of resonance. The primary objective of this experiment was to measure the generated thrust. A mean value of thrust was measured up to 6.0 lb, corresponding to H2 flow based specific impulse of 2970 s. This value is comparable to measurements in H2-fueled pulsed detonation engines (PDEs). The injection and detonation frequency for this new experimental case was much higher than typical PDEs, where frequencies are usually less than 100 Hz. The compact size of the device and high frequency of detonation yields a thrust-per-unit-volume of approximately 2.0 pounds per cubic inch, and compares favorably with other experiments, which typically have thrust-per-unit-volume of order 0.01 pound per cubic inch. This much higher volumetric efficiency results in a potentially much more practical device than the typical PDE, for a wide range of potential applications, including high-speed boundary layer separation control, for example in hypersonic engine inlets, and propulsion for small aircraft and missiles.

  8. Observation of selective surface element substitution in FeTe0.5Se0.5 superconductor thin film exposed to ambient air by synchrotron radiation spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Nian; Liu, Chen; Zhao, Jia-Li; Lei, Tao; Wang, Jia-Ou; Qian, Hai-Jie; Wu, Rui; Yan, Lei; Guo, Hai-Zhong; Ibrahim, Kurash

    2016-09-01

    A systematic investigation of oxidation on a superconductive FeTe0.5Se0.5 thin film, which was grown on Nb-doped SrTiO3 (001) by pulsed laser deposition, has been carried out. The sample was exposed to ambient air for one month for oxidation. Macroscopically, the exposed specimen lost its superconductivity due to oxidation. The specimen was subjected to in situ synchrotron radiation photoelectron spectroscopy (PES) and x-ray absorption spectroscopy (XAS) measurements following cycles of annealing and argon ion etching treatments to unravel what happened in the electronic structure and composition after exposure to air. By the spectroscopic measurements, we found that the as-grown FeTe0.5Se0.5 superconductive thin film experienced an element selective substitution reaction. The oxidation preferentially proceeds through pumping out the Te and forming Fe–O bonds by O substitution of Te. In addition, our results certify that in situ vacuum annealing and low-energy argon ion etching methods combined with spectroscopy are suitable for depth element and valence analysis of layered structure superconductor materials. Project supported by the Chinese Academy of Sciences (Grant No. 1G2009312311750101) and the National Natural Science Foundation of China (Grant Nos. 11375228, 11204303, and U1332105).

  9. Observation of selective surface element substitution in FeTe0.5Se0.5 superconductor thin film exposed to ambient air by synchrotron radiation spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Nian; Liu, Chen; Zhao, Jia-Li; Lei, Tao; Wang, Jia-Ou; Qian, Hai-Jie; Wu, Rui; Yan, Lei; Guo, Hai-Zhong; Ibrahim, Kurash

    2016-09-01

    A systematic investigation of oxidation on a superconductive FeTe0.5Se0.5 thin film, which was grown on Nb-doped SrTiO3 (001) by pulsed laser deposition, has been carried out. The sample was exposed to ambient air for one month for oxidation. Macroscopically, the exposed specimen lost its superconductivity due to oxidation. The specimen was subjected to in situ synchrotron radiation photoelectron spectroscopy (PES) and x-ray absorption spectroscopy (XAS) measurements following cycles of annealing and argon ion etching treatments to unravel what happened in the electronic structure and composition after exposure to air. By the spectroscopic measurements, we found that the as-grown FeTe0.5Se0.5 superconductive thin film experienced an element selective substitution reaction. The oxidation preferentially proceeds through pumping out the Te and forming Fe-O bonds by O substitution of Te. In addition, our results certify that in situ vacuum annealing and low-energy argon ion etching methods combined with spectroscopy are suitable for depth element and valence analysis of layered structure superconductor materials. Project supported by the Chinese Academy of Sciences (Grant No. 1G2009312311750101) and the National Natural Science Foundation of China (Grant Nos. 11375228, 11204303, and U1332105).

  10. Ligand Shell Composition-Dependent Effects on the Apparent Hydrophobicity and Film Behavior of Gold Nanoparticles at the Air-Water Interface.

    PubMed

    Bradford, Stephen M; Fisher, Elizabeth A; Meli, M-Vicki

    2016-09-27

    Nanoparticles with well-defined interfacial energy and wetting properties are needed for a broad range of applications involving nanoparticle self-assembly including the formation of superlattices, stability of Pickering emulsions, and for the control of nanoparticle interactions with biological membranes. Theoretical, simulated, and recent experimental studies have found nanometer-scale chemical heterogeneity to have important effects on hydrophobic interactions. Here we report the study of 4 nm gold nanoparticles with compositionally well-defined mixed ligand shells of hydroxyl-(OH) and methyl-(CH3) terminated alkylthiols as Langmuir films. Compositions ranging from 0-25% hydroxyl were examined and reveal nonmonotonic changes in particle hydrophobicity at the air-water interface. Unlike nanoparticles capped exclusively with a methyl-terminated alkylthiol, extensive particle aggregation is found for ligand shells containing <2% hydroxyl-terminated chains. This aggregation was lessened upon increasing the quantity of OH-terminated chains. Nanoparticles capped with 25% OH yield films of well-separated nanoparticles exhibiting a fluid-phase regime in the surface pressure vs area isotherm. Compression-expansion hysteresis, monolayer collapse, and mean nanoparticle area measurements support the TEM-observed changes in film morphology. Such clear changes in the hydrophobicity of nanoparticles based on very small changes in the ligand shell composition are shown to impact the process of interfacial nanoparticle self-assembly and are an important demonstration of nanoscale wetting with consequences in both materials and biological applications of nanoparticles that require tunable hydrophobicity. PMID:27594307

  11. Effects of Ambient Air and Temperature on Ionic Gel Gated Single-Walled Carbon Nanotube Thin-Film Transistor and Circuits.

    PubMed

    Li, Huaping; Zhou, Lili

    2015-10-21

    Single-walled carbon nanotube thin-film transistor (SWCNT TFT) and circuits were fabricated by fully inkjet printing gold nanoparticles as source/drain electrodes, semiconducting SWCNT thin films as channel materials, PS-PMMA-PS/EMIM TFSI composite gel as gate dielectrics, and PEDOT/PSS as gate electrodes. The ionic gel gated SWCNT TFT shows reversible conversion from p-type transistor behavior in air to ambipolar features under vacuum due to reversible oxygen doping in semiconducting SWCNT thin films. The threshold voltages of ionic gel gated SWCNT TFT and inverters are largely shifted to the low value (0.5 V for p-region and 1.0 V for n-region) by vacuum annealing at 140 °C to exhausively remove water that is incorporated in the ionic gel as floating gates. The vacuum annealed ionic gel gated SWCNT TFT shows linear temperature dependent transconductances and threshold voltages for both p- and n-regions. The strong temperature dependent transconductances (0.08 μS/K for p-region, 0.4 μS/K for n-region) indicate their potential application in thermal sensors. In the other hand, the weak temperature dependent threshold voltages (-1.5 mV/K for p-region, -1.1 mV/K for n-region) reflect their excellent thermal stability.

  12. Two-dimensional crystallization of catalase on a monolayer film of poly(1-benzyl-L-histidine) spread at the air/water interface.

    PubMed

    Sato, A; Furuno, T; Toyoshima, C; Sasabe, H

    1993-03-01

    Two-dimensional (2D) crystals of beef liver catalase were prepared by adsorption to a film of synthetic polypeptide, poly(1-benzyl-L-histidine) (PBLH), spread at the air/water interface. The crystallization experiments were carried out in the pH range of 4.8-6.4 for catalase solutions at low concentration (10 micrograms/ml). The pH-dependence suggested an electrostatic interaction in the binding of catalase to the PBLH film. At lower pH, small crystals were formed at a low binding rate, and at higher pH the binding was rapid and densely-packed 2D arrays with poor crystallinity were formed. To stimulate crystal growth, a thermal treatment was applied. One-shot heating of the interfacial catalase-PBLH film to 35-40 degrees C was remarkably effective to form larger 2D crystals. The structure of catalase 2D crystals has been analyzed by Fourier filtering of the transmission electron micrographs. The crystal form is a new one, containing four catalase molecules in the unit cell with lattice parameters of alpha = 187 A, b = 225 A and gamma = 92.8 degrees.

  13. Thrust Performance of a Low Power Hall Thruster

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naoji; Ezaki, Toru; Nakashima, Hideki

    For the application of Hall thrusters to small satellites, we have been developing a low power Hall thruster. As an initial test, we evaluated the thrust performance of a 50 W class miniature Hall thruster developed at Kyushu University. The outer diameter and the length of the acceleration channel are 18 mm and 7 mm, respectively. A torsional type thrust stand was developed, since the estimated thrust is 1-3 mN, which is too small to be measured by means of a conventional pendulum type thrust stand for Hall thrusts. The uncertainty of this thrust stand is less than 10% at 2 mN with calibration. The thrust, the discharge current, specific impulse and the thrust efficiency at xenon mass flow rate of 0.30 mg/s and discharge voltage of 125 V were 1.7 mN, 0.35 A, 600 sec and 11.4%, respectively. The thrust increased with an increase in discharge voltage and the thrust became 3.1 mN at discharge voltage of 250 V.

  14. High-power, null-type, inverted pendulum thrust stand

    NASA Astrophysics Data System (ADS)

    Xu, Kunning G.; Walker, Mitchell L. R.

    2009-05-01

    This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The thrust stand position serves as the input to the null-circuit feedback control system and the output is the current to an electromagnetic actuator. Mechanical oscillations are actively damped with an electromagnetic damper. A closed-loop inclination system levels the stand while an active cooling system minimizes thermal effects. The thrust stand incorporates an in situ calibration rig. The thrust of a 3.4 kW Hall thruster is measured for thrust levels up to 230 mN. The uncertainty of the thrust measurements in this experiment is ±0.6%, determined by examination of the hysteresis, drift of the zero offset and calibration slope variation.

  15. High-power, null-type, inverted pendulum thrust stand.

    PubMed

    Xu, Kunning G; Walker, Mitchell L R

    2009-05-01

    This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The thrust stand position serves as the input to the null-circuit feedback control system and the output is the current to an electromagnetic actuator. Mechanical oscillations are actively damped with an electromagnetic damper. A closed-loop inclination system levels the stand while an active cooling system minimizes thermal effects. The thrust stand incorporates an in situ calibration rig. The thrust of a 3.4 kW Hall thruster is measured for thrust levels up to 230 mN. The uncertainty of the thrust measurements in this experiment is +/-0.6%, determined by examination of the hysteresis, drift of the zero offset and calibration slope variation.

  16. Initiation of a thrust fault revealed by analog experiments

    NASA Astrophysics Data System (ADS)

    Dotare, Tatsuya; Yamada, Yasuhiro; Adam, Juergen; Hori, Takane; Sakaguchi, Hide

    2016-08-01

    To reveal in detail the process of initiation of a thrust fault, we conducted analog experiments with dry quartz sand using a high-resolution digital image correlation technique to identify minor shear-strain patterns for every 27 μm of shortening (with an absolute displacement accuracy of 0.5 μm). The experimental results identified a number of "weak shear bands" and minor uplift prior to the initiation of a thrust in cross-section view. The observations suggest that the process is closely linked to the activity of an adjacent existing thrust, and can be divided into three stages. Stage 1 is characterized by a series of abrupt and short-lived weak shear bands at the location where the thrust will subsequently be generated. The area that will eventually be the hanging wall starts to uplift before the fault forms. The shear strain along the existing thrust decreases linearly during this stage. Stage 2 is defined by the generation of the new thrust and active displacements along it, identified by the shear strain along the thrust. The location of the new thrust may be constrained by its back-thrust, generally produced at the foot of the surface slope. The activity of the existing thrust falls to zero once the new thrust is generated, although these two events are not synchronous. Stage 3 of the thrust is characterized by a constant displacement that corresponds to the shortening applied to the model. Similar minor shear bands have been reported in the toe area of the Nankai accretionary prism, SW Japan. By comparing several transects across this subduction margin, we can classify the lateral variations in the structural geometry into the same stages of deformation identified in our experiments. Our findings may also be applied to the evaluation of fracture distributions in thrust belts during unconventional hydrocarbon exploration and production.

  17. Mercury's global fabric of thrust faults

    NASA Astrophysics Data System (ADS)

    Klimczak, C.; Byrne, P. K.; Solomon, S. C.

    2014-12-01

    Mercury's global tectonic history is thought to have been shaped by two major processes: tidal despinning and global contraction. Each process is expected to have produced a distinctive global stress field and resultant fault pattern. Data from three years of orbital operations by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft reveal thousands of thrust faults that are attributed to global contraction, but no global signature of tidal despinning has been conclusively documented. Global contraction operated throughout an extended portion of Mercury's geologic history, whereas tidal despinning likely operated for a shorter duration. Therefore, any tidal despinning pattern, if not entirely obliterated by the late heavy bombardment, either would have formed together with global contraction, or would have been modified by global contraction after despinning was complete. Here, we reassess global fracture patterns predicted to result from tidal despinning alone, and from a combination of tidal despinning and global contraction. We specifically make use of rock strength and deformability parameters appropriate for Mercury's fractured lithosphere. Our results indicate that a tidal despinning pattern would consist only of a global set of opening-mode fractures (joints) in the upper part of the lithosphere, whereas the combination of tidal despinning and global contraction would have produced a global population of thrust faults, with no preferred orientations in the polar regions but with an increasing preference for north-south orientations toward the equator. If an equatorial bulge from an early state of rapid spin were supported by Mercury's lithosphere, two end-member scenarios for the timing and duration of these two processes can be considered. In one, tidal despinning predated global contraction; in the other, tidal despinning and global contraction temporally overlapped. We test the predictions for both scenarios against the

  18. STOL landing thrust: Reverser jet flowfields

    NASA Technical Reports Server (NTRS)

    Kotansky, D. R.; Glaze, L. W.

    1987-01-01

    Analysis tools and modeling concepts for jet flow fields encountered upon use of thrust reversers for high performance military aircraft are described. A semi-empirical model of the reverser ground wall jet interaction with the uniform cross flow due to aircraft forward velocity is described. This ground interaction model is used to demonstrate exhaust gas ingestion conditions. The effects of control of exhaust jet vector angle, lateral splay, and moving versus fixed ground simulation are discussed. The Adler/Baron jet-in-cross flow model is used in conjunction with three dimensional panel methods to investigate the upper surface jet induced flow field.

  19. Measuring HOMO/LUMO gap of explosive film at air interface using ESFG: model for explosive at void surface

    NASA Astrophysics Data System (ADS)

    Farrow, Darcie; Kohl, Ian; Kearney, Sean; Rupper, Stephen; Martin, Laura; Alam, Kathy; Knepper, Robert; Kay, Jeffery

    Vibrational broadband sum frequency generation has enabled measurements of heat transfer/disorder under shock compression on monolayer length scales (Carter, JPCA, 2008). At Sandia, we are extending this approach to examine shock-induced changes in the electronic structure of secondary explosives at surfaces using electronic sum frequency generation (ESFG)(Yamaguchi, JCP, 2008). Theoretical studies suggest explosives at voids and grain boundaries may have different reactivity than bulk material based on shifts in the bandgap at defects (Kuklja, Appl. Phys. A 2003). We seek to measure these electronic shifts for the first time using a thin film explosive samples as a model for the void surface. We will report electronic sum frequency data from vapour deposited thin film explosive compared to UV/Vis data of the bulk film at ambient pressures and discuss application of ESFG technique to samples under shock compression.

  20. Reconciling Himalayan midcrustal discontinuities: The Main Central thrust system

    NASA Astrophysics Data System (ADS)

    Larson, Kyle P.; Ambrose, Tyler K.; Webb, A. Alexander G.; Cottle, John M.; Shrestha, Sudip

    2015-11-01

    The occurrence of thrust-sense tectonometamorphic discontinuities within the exhumed Himalayan metamorphic core can be explained as part of the Main Central thrust system. This imbricate thrust structure, which significantly thickened the orogenic midcrustal core, comprises a series of thrust-sense faults that all merge into a single detachment. The existence of these various structures, and their potential for complex overprinting along the main detachment, may help explain the contention surrounding the definition, mapping, and interpretation of the Main Central thrust. The unique evolution of specific segments of the Main Central thrust system along the orogen is interpreted to be a reflection of the inherent basement structure and ramp position, and structural level of exposure of the mid-crust. This helps explain the variation in the timing and structural position of tectonometamorphic discontinuities along the length of the mountain belt.

  1. Fluid storage and transport in thrust belts: the Gavarnie Thrust system revisited

    NASA Astrophysics Data System (ADS)

    McCaig, Andrew

    2015-04-01

    There has been renewed interest in the pressure and movement of fluids in thrust systems in recent years with the discovery and increasing importance of slow slip earthquakes. Unfortunately the overpressured regime thought to be the source region for both normal and slow-slip earthquakes is inaccessible to direct observation, so information about the actual water content, flow regimes and permeability structure at the time of thrusting can only be obtained in exhumed rocks. The Gavarnie Thrust System in the Pyrenees (including the immediate footwall of the thrust and overlying thrust sheets) is exceptionally well studied in terms of structural and microstructural work, fluid inclusions, and isotopic tracing of fluid flow. Southward thrusting by 12-15 km occurred during the Eocene, and the current geometry of the thrust is a broad dome, allowing sampling at many locations. There is abundant evidence for near-lithostatic fluid pressures at depths of 8-15 km in the crust and temperatures of 300-400 °C, and fluids at these levels are dominated by hypersaline brines with Cl/Br ratios indicating evaporation of seawater. They are inferred to be derived from widespread Triassic evaporates, and stored in underlying redbeds and fractured basement rocks. There is also evidence from fluid inclusions for periodic pressure cycling down to near-hydrostatic values. This is thought to be related to co-seismic fault valve behaviour with release of fluid both into the shallow thrust and into steeply dipping shear zones in the hangingwall. Isotopic studies of carbonate mylonites along the Gavarnie thrust indicate unidirectional southward (structurally upward) flow of fluid , again probably mainly during transient veining events. These relatively slow moving fluids appear to have fed into a hydrostatic regime with topographically driven flow at higher levels. If time averaged permeability was high, most of the fluid would have rapidly escaped, since there is little opportunity to

  2. Cretaceous biostratigraphy in the Wyoming thrust belt

    SciTech Connect

    Nichols, D.J.; Jacobson, S.R.

    1982-07-01

    Biostratigraphy is essential to exploration for oil and gas in the Wyoming thrust belt because fossils provide a temporal framework for interpretation of events of faulting, erosion, sedimentation, and the development of hydrocarbon traps and migration pathways. In the Cretaceous section, fossils are especially useful for dating and correlating repetitive facies of different ages in structurally complex terrain. The biostratigraphic zonation for the region is based on megafossils (chiefly ammonites), which permit accurate dating and correlation of outcrop sections, and which have been calibrated with the radiometric time scale for the Western Interior. Molluscan and vertebrate zone fossils are difficult to obtain from the subsurface, however, and ammonities are restricted to rocks of margin origin. Palynomorphs (plant microfossils) have proven to be the most valuable fossils in investigations of stratigraphy and structures in the subsurface of the thrust belt because palynomorphs can be recovered from drill cuttings. Palynomorphs also are found in both marine and nonmarine rocks and can be used for correlation between facies. In this paper, stratigraphic ranges of selected Cretaceous marine and nonmarine palynomorphs in previously designated reference sections in Fossil Basin, Wyoming, are correlated with the occurrence of ammonities and other zone fossils in the same sections. These correlations can be related to known isotopic ages, and they contribute to the calibration of palynomorph ranges in the Cretaceous of the Western Interior.

  3. Experimental Results of Schlicher's Thrusting Antenna

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Niedra, Janis M.

    2001-01-01

    Experiments were conducted to test the claims by Rex L. Schlicher, et al., (Patent 5,142,86 1) that a certain antenna geometry produces thrust greatly exceeding radiation reaction, when driven by repetitive, fast rise, and relatively slower decay current pulses. In order to test this hypothesis, the antenna was suspended by strings as a 3 in pendulum. Current pulses were fed to the antenna along the suspension path by a very flexible coaxial line constructed from loudspeaker cable and copper braid sheath. When driving the antenna via this cabling, our pulser was capable of sustaining 1200 A pulses at a rate of 30 per second up to a minute. In this way, bursts of pulses could be delivered in synch with the pendulum period in order to build up any motion. However, when using a laser beam passing through a lens attached to the antenna to amplify linear displacement by a factor of at least 25, no correlated motion of the beam spot could be detected on a distant wall. We conclude, in agreement with the momentum theorem of classical electromagnetic theory, that any thrust produced is far below practically useful levels. Hence, within classical electrodynamics, there is little hope of detecting any low level motion that cannot be explained by interactions with surrounding structural steel and the Earth's magnetic field.

  4. Thrust vector control using electric actuation

    SciTech Connect

    Bechtel, R.T.; Hall, D.K.

    1995-01-25

    Presently, gimbaling of launch vehicle engines for thrust vector control is generally accomplished using a hydraulic system. In the case of the space shuttle solid rocket boosters and main engines, these systems are powered by hydrazine auxiliary power units. Use of electromechanical actuators would provide significant advantages in cost and maintenance. However, present energy source technologies such as batteries are heavy to the point of causing significant weight penalties. Utilizing capacitor technology developed by the Auburn University Space Power Institute in collaboration with the Auburn CCDS, Marshall Space Flight Center (MSFC) and Auburn are developing EMA system components with emphasis on high discharge rate energy sources compatible with space shuttle type thrust vector control requirements. Testing has been done at MSFC as part of EMA system tests with loads up to 66000 newtons for pulse times of several seconds. Results show such an approach to be feasible providing a potential for reduced weight and operations costs for new launch vehicles. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}

  5. Rocket thrust chamber thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Batakis, A. P.; Vogan, J. W.

    1985-01-01

    A research program was conducted to generate data and develop analytical techniques to predict the performance and reliability of ceramic thermal barrier coatings in high heat flux environments. A finite element model was used to analyze the thermomechanical behavior of coating systems in rocket thrust chambers. Candidate coating systems (using a copper substrate, NiCrAlY bond coat and ZrO2.8Y2O3 ceramic overcoat) were selected for detailed study based on photomicrographic evaluations of experimental test specimens. The effects of plasma spray application parameters on the material properties of these coatings were measured and the effects on coating performance evaluated using the finite element model. Coating design curves which define acceptable operating envelopes for seleted coating systems were constructed based on temperature and strain limitations. Spray gun power levels was found to have the most significant effect on coating structure. Three coating systems were selected for study using different power levels. Thermal conductivity, strain tolerance, density, and residual stress were measured for these coatings. Analyses indicated that extremely thin coatings ( 0.02 mm) are required to accommodate the high heat flux of a rocket thrust chamber and ensure structural integrity.

  6. OMV/VTE variable thrust engine analysis

    NASA Technical Reports Server (NTRS)

    Larosillere, Louis; Litchford, Ron; Jeng, San-Mou

    1989-01-01

    The objective of the present work is to develop a predictive CFD based analytical tool for the variable thrust engine (VTE) in the orbital maneuvering vehicle (OMV). This objective is being accomplished within the framework of the Los Alamos KIVA computer code for chemically reactive flows with sprays. For the OMV application, the main structure of KIVA is to be retained while reformulating many of the phenomenological submodels, enhancing some of the numerics, and adding more features. The analytical model consists of the general conservation equations for two phase reactive flows and of submodels for turbulence, chemical reactions, and bipropellant sprays. Tailoring this model to the OMV engine brings about the added complexities of combustion and flow processes that occur in a liquid hypergolic propellant rocket chamber. This report exposes the foundation upon which the analytical tool is being constructed and developed. Results from a cursory computational exercise involving the simulation of the flow and combustion processes in a hypothetical N2H4/N2O4 rocket engine thrust chamber is presented and discussed.

  7. OMV/VTE variable thrust engine analysis

    NASA Technical Reports Server (NTRS)

    Larosillere, L.; Litchford, R.; Jeng, S. M.

    1995-01-01

    The objective of the present work is to develop a predictive CFD based analytical tool for the Variable Thrust Engine (VTE) in the Orbital Maneuvering Vehicle (OMV). This objective is being accomplished within the framework of the Los Alamos KIVA computer code for chemically reactive flows with sprays. For the OMV application, the main structure of KIVA is to be retained while reformulating many of the phenomenological submodels, enhancing some of the numerics, and adding more features. The analytical model consists of the general conservation equations for two-phase reactive flows and of submodels for turbulence, chemical reactions, and bipropellant sprays. Tailoring this model to the OMV engine brings about the added complexities of combustion and flow processes that occur in a liquid hypergolic propellant rocket chamber. This report exposes the foundation upon which the analytical tool is being constructed and developed. Results from a cursory computational exercise involving the simulation of the flow and combustion processes in a hypothetical N2H4/N204 rocket engine thrust chamber is presented and discussed.

  8. Emergency Control Aircraft System Using Thrust Modulation

    NASA Technical Reports Server (NTRS)

    Burken, John J. (Inventor); Burcham, Frank W., Jr. (Inventor)

    2000-01-01

    A digital longitudinal Aircraft Propulsion Control (APC system of a multiengine aircraft is provided by engine thrust modulation in response to comparing an input flightpath angle signal (gamma)c from a pilot thumbwheel. or an ILS system with a sensed flightpath angle y to produce an error signal (gamma)e that is then integrated (with reasonable limits) to generate a drift correction signal to be added to the error signal (gamma)e after first subtracting a lowpass filtered velocity signal Vel(sub f) for phugoid damping. The output error signal is multiplied by a constant to produce an aircraft thrust control signal ATC of suitable amplitude to drive a throttle servo for all engines. each of which includes its own full-authority digital engine control (FADEC) computer. An alternative APC system omits sensed flightpath angle feedback and instead controls the flightpath angle by feedback of the lowpass filtered velocity signal Vel(sub f) which also inherently provides phugoid damping. The feature of drift compensation is retained.

  9. 3D Two-way coupled TEHD analysis on the lubricating characteristics of thrust bearings in pump-turbine units by combining CFD and FEA

    NASA Astrophysics Data System (ADS)

    Zhai, Liming; Luo, Yongyao; Wang, Zhengwei; Liu, Xin

    2016-01-01

    The thermal elastic hydro dynamic (TEHD) lubrication analysis for the thrust bearing is usually conducted by combining Reynolds equation with finite element analysis (FEA). But it is still a problem to conduct the computation by combining computational fluid dynamics (CFD) and FEA which can simulate the TEHD more accurately. In this paper, by using both direct and separate coupled solutions together, steady TEHD lubrication considering the viscosity-temperature effect for a bidirectional thrust bearing in a pump-turbine unit is simulated combining a 3D CFD model for the oil film with a 3D FEA model for the pad and mirror plate. Cyclic symmetry condition is used in the oil film flow as more reasonable boundary conditions which avoids the oil temperature assumption at the leading and trailing edge. Deformations of the pad and mirror plate are predicted and discussed as well as the distributions of oil film thickness, pressure, temperature. The predicted temperature shows good agreement with measurements, while the pressure shows a reasonable distribution comparing with previous studies. Further analysis of the three-coupled-field reveals the reason of the high pressure and high temperature generated in the film. Finally, the influence of rotational speed of the mirror plate on the lubrication characteristics is illustrated which shows the thrust load should be balanced against the oil film temperature and pressure in optimized designs. This research proposes a thrust bearing computation method by combining CFD and FEA which can do the TEHD analysis more accurately.

  10. A 3-D Model of Stacked Thrusts in the Sevier Thrust Belt, Eastern Idaho

    NASA Astrophysics Data System (ADS)

    Clayton, R. W.; Clayton, S. R.

    2014-12-01

    Using published and new geologic map data and two exploratory wells for control, we constructed a three-dimensional geological model of the Pine Creek area in the Big Hole Mountains of eastern Idaho, where stacked Sevier thrust sheets are exposed at the surface. In this area, Cretaceous crustal shortening displaced and folded strata from Cambrian to Cretaceous in age. Using geologic map data as a primary input to a 3-D model presents a number of challenges, especially representing fault geometries at depth and maintaining strata thicknesses. The highly variable attitudes measured at the surface are also difficult to represent in a subsurface model because they require extensive extrapolation to depth. To overcome these challenges we EarthVision software, which has tools for model construction with minimal data inputs and uses a minimum tension algorithm to create geologically realistic surfaces. We also constructed two primary cross-sections to constrain strata and fault geometries according to structural principles, and used these to guide construction of fault and horizon surfaces. We then designated horizons with the best control as reference horizons to constrain strata geometries, and built the remaining horizons using isochores to add or subtract from those surfaces. The model shows classic flat-ramp thrust geometries as seen farther southeast in the Wyoming section of the thrust belt. The model also shows uniform southwestward tilting of faults and strata in the north end above younger thrusts, but strong effects from a duplex on a younger thrust fault encountered in the southern well, which rotated the strata and older faults above it.

  11. Design and test of a magnetic thrust bearing

    NASA Technical Reports Server (NTRS)

    Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.

    1993-01-01

    A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

  12. Large-Scale Wind-Tunnel Tests of Exhaust Ingestion Due to Thrust Reversal on a Four-Engine Jet Transport during Ground Roll

    NASA Technical Reports Server (NTRS)

    Tolhurst, William H., Jr.; Hickey, David H.; Aoyagi, Kiyoshi

    1961-01-01

    Wind-tunnel tests have been conducted on a large-scale model of a swept-wing jet transport type airplane to study the factors affecting exhaust gas ingestion into the engine inlets when thrust reversal is used during ground roll. The model was equipped with four small jet engines mounted in nacelles beneath the wing. The tests included studies of both cascade and target type reversers. The data obtained included the free-stream velocity at the occurrence of exhaust gas ingestion in the outboard engine and the increment of drag due to thrust reversal for various modifications of thrust reverser configuration. Motion picture films of smoke flow studies were also obtained to supplement the data. The results show that the free-stream velocity at which ingestion occurred in the outboard engines could be reduced considerably, by simple modifications to the reversers, without reducing the effective drag due to reversed thrust.

  13. High-mobility, air stable bottom-contact n-channel thin film transistors based on N,N′-ditridecyl perylene diimide

    SciTech Connect

    Ma, Lanchao; Guo, Yunlong; Wen, Yugeng; Liu, Yunqi E-mail: liuyq@iccas.ac.cn; Zhan, Xiaowei E-mail: liuyq@iccas.ac.cn

    2013-11-11

    Bottom-gate bottom-contact (BGBC) organic thin film transistors (OTFTs) based on N,N′-ditridecyl perylene diimide exhibit electron mobility as high as 3.54 cm{sup 2} V{sup −1} s{sup −1} in nitrogen, higher than that (1 cm{sup 2} V{sup −1} s{sup −1}) of bottom-gate top-contact devices. The better performance of BGBC configuration in N{sub 2} is attributed to lower contact resistance, which is further reduced by thermal annealing. After thermally annealing the BGBC OTFTs at 180 °C, electron mobility as high as 3.5 cm{sup 2} V{sup −1} s{sup −1}, current on/off ratio of 10{sup 6} and threshold voltage of 9 V are achieved in air, and the mobility retains above 1 cm{sup 2} V{sup −1} s{sup −1} after storage for two months in air. Thermal treatment enhanced crystalline grains, reduced grain boundaries, and suppressed the adsorption of H{sub 2}O and O{sub 2}, leading to excellent performance in air.

  14. A review of thrust-vectoring schemes for fighter applications

    NASA Technical Reports Server (NTRS)

    Berrier, B. L.; Re, R. J.

    1978-01-01

    This paper presents a review of thrust vectoring schemes for advanced fighter applications. Results are presented from wind tunnel and system integration studies on thrust vectoring nozzle concepts. Vectoring data are presented from wind tunnel tests of axisymmetric C-D (convergent-divergent) and nonaxisymmetric wedge, C-D, single ramp and USB (upper-surface blowing) nozzle concepts. Results from recent airframe/nozzle integration studies on the impact of thrust vectoring on weight, cooling and performance characteristics are discussed. This review indicates that the aircraft designer has, at his disposal, a wide range of thrust vectoring schemes which offer potential for added or improved aircraft capability.

  15. Unsteady thrust measurement techniques for pulse detonation engines

    NASA Astrophysics Data System (ADS)

    Joshi, Dibesh Dhoj

    Thrust is a critical performance parameter and its correct determination is necessary to characterize an engine. Many conventional thrust measurement techniques prevail. However, further developments are required for correct measurement of thrust in the case of a pulse detonation engine (PDE), since the entire thrust generation process is intermittent. The significant effect of system dynamics in the form of inertial forces, stress wave propagation and reflections initiated in the structure due to detonations and pulse-to-pulse interaction in a fast operating PDE further complicate the thrust measurement process. These complications call for a further, detailed study of the unsteady thrust characteristics. A general approach was first developed to recover actual thrust from the measured thrust generated by the PDE. The developed approach consisted of two steps. The first step incorporated a deconvolution procedure using a pre-established system transfer function and measured input to reconstruct the output yielding the deconvolved thrust. The second step accounted for inertial forces through an acceleration compensation procedure. These two steps allowed the actual thrust to be determined. A small scale PDE operating at 10 and 20 Hz with varied filling fractions and mixture equivalence ratios was used for the experimental application of the general approach. The analytical study of gas dynamics in the PDE while in operation and the measured pressure histories at the exit of the engine allowed the generated thrust during a cycle to be determined semi-empirically. The thrust values determined semi-empirically were compared against the experimental results. A dynamical model of the PDE was created for the study of the unsteady thrust characteristics using finite element analysis. The results from finite element analysis were compared against semi-empirical and experimental results. In addition, finite element analysis also facilitated to numerically determine the

  16. Space shuttle orbit maneuvering engine reusable thrust chamber program

    NASA Technical Reports Server (NTRS)

    Senneff, J. M.

    1975-01-01

    The feasibility of potential reusable thrust chamber concepts is studied. Propellant condidates were examined and analytically combined with potential cooling schemes. A data base of engine data which would assist in a configuration selection was produced. The data base verification was performed by the demonstration of a thrust chamber of a selected coolant scheme design. A full scale insulated columbium thrust chamber was used for propellant coolant configurations. Combustion stability of the injectors and a reduced size thrust chamber were experimentally verified as proof of concept demonstrations of the design and study results.

  17. Kinematic modeling of folding above listric propagating thrusts

    NASA Astrophysics Data System (ADS)

    Cardozo, Nestor; Brandenburg, J. P.

    2014-03-01

    We describe a kinematic approach to simulate folds above listric propagating thrusts. The model is based on a pre-defined circular thrust geometry with a maximum central angle beyond which the thrust is planar, inclined shear above the circular thrust, and trishear in front of the thrust. Provided the trajectory of thrust propagation is established, the model can be run forward and backwards. We use this last feature to implement a global simulated annealing, inverse modeling strategy. This inverse modeling strategy is applied to synthetic folds as well as two real examples in offshore Venezuela and the Niger Delta toe-thrust system. These three examples illustrate the benefits of the algorithm, particularly in predicting the possible range of models that can fit the structures. Thrust geometry, depth to detachment level, and backlimb geometry have high impact in model parameters such as backlimb shear angle and fault slip; while forelimb geometry is critical to constrain parameters such as fault propagation to fault slip ratio and trishear angle. Steep to overturned beds in forelimb areas are often not imaged by seismic, so in the absence of additional well data, considering all possible thrust-fold geometries is critical for the modeling and whatever prediction (e.g. hydrocarbon trap integrity) is made from it.

  18. Vista/F-16 Multi-Axis Thrust Vectoring (MATV) control law design and evaluation

    NASA Technical Reports Server (NTRS)

    Zwerneman, W. D.; Eller, B. G.

    1994-01-01

    For the Multi-Axis Thrust Vectoring (MATV) program, a new control law was developed using multi-axis thrust vectoring to augment the aircraft's aerodynamic control power to provide maneuverability above the normal F-16 angle of attack limit. The control law architecture was developed using Lockheed Fort Worth's offline and piloted simulation capabilities. The final flight control laws were used in flight test to demonstrate tactical benefits gained by using thrust vectoring in air-to-air combat. Differences between the simulator aerodynamics data base and the actual aircraft aerodynamics led to significantly different lateral-directional flying qualities during the flight test program than those identified during piloted simulation. A 'dial-a-gain' flight test control law update was performed in the middle of the flight test program. This approach allowed for inflight optimization of the aircraft's flying qualities. While this approach is not preferred over updating the simulator aerodynamic data base and then updating the control laws, the final selected gain set did provide adequate lateral-directional flying qualities over the MATV flight envelope. The resulting handling qualities and the departure resistance of the aircraft allowed the 422nd_squadron pilots to focus entirely on evaluating the aircraft's tactical utility.

  19. F-15B ACTIVE with thrust vectoring nozzles on test stand view from rear

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This November 13, 1995, photograph of the F-15 Advanced Controls Technology for Integrated Vehicles (ACTIVE) at NASA's Dryden Flight Research Center, Edwards, California, shows the aircraft's two new Pratt & Whitney nozzles that can turn up to 20 degrees in any direction. These nozzles give the aircraft thrust control in the pitch (up and down) and yaw (left and right) directions. This will reduce drag and increase fuel economy or range as compared with conventional aerodynamic controls, which increase the retarding forces (drag) acting upon the aircraft. Ground testing of a new thrust-vectoring concept employing the nozzles took place during the first two weeks of November 1995 and went well, and flight tests began in March 1996. These tests could result in significant performance increases for military and commercial aircraft. The research program is the product of a collaborative effort by NASA, the Air Force's Wright Laboratory, Pratt & Whitney, and McDonnell Douglas Aerospace.

  20. Investigation of Thrust and Drag Characteristics of a Plug-type Exhaust Nozzle

    NASA Technical Reports Server (NTRS)

    Hearth, Donald P; Gorton, Gerald C

    1954-01-01

    An investigation was conducted in the 8- by 6-foot supersonic wind tunnel on the external and internal characteristics of a plug-type exhaust nozzle. Two positions of the center plug, one simulating a convergent nozzle and the other a convergent-divergent nozzle, were investigated. Data were obtained at free-stream Mach numbers of 0.1, 0.6, 1.6, and 2.0 over a pressure-ratio range of 1 to 20 and angles of attack of zero and 8 degrees. Results of this investigation indicated that the plug nozzle had thrust-minus-drag performance over the entire pressure-ratio range comparable with equivalent conventional nozzles. The effect of the exhaust jet on the external aerodynamics was similar to results observed for conventional nozzles. In addition, the thrust characteristics were generally insensitive to external flow and good agreement was noted with data obtained on comparable plug nozzles in quiescent air.

  1. Film ispalators

    SciTech Connect

    Startsev, Aleksandr V; Stoilov, Yurii Yu

    2002-05-31

    New physical objects, ispalators based on free soap films, exhibit persistent flows of the soap solution in open and closed volumes in air with additions of gases of the C{sub 8}F{sub 18} type (p = 20 Torr) at temperature drops on the films of the order of tenths and hundredths of kelvin. The flows move continuously at a velocity of 5 - 20 cm s{sup -1}. It is found that the parts of an inclined ispalator film show anomalous behaviour upon heating: their weight increases and they move downward over the film, whereas the unheated parts of the film move upward. Continuous radial vortex flows accompanied by the formation and washing of the regions of a thin black film are observed on circular films in closed volumes upon their uniform external cooling by evaporating water for 5 - 10 hours. The rapid flows make film ispalators the efficient heat carriers, which operate at small temperature drops (tenths and hundredths of kelvin) and surpass copper in the amount of thermal energy being transferred. The outlook for the further study and applications of film ispalators for detecting thermal fields and laser radiation is discussed. (laser applications and other topics in quantum electronics)

  2. An investigation of corner separation within a thrust augmenter having Coanda jets

    NASA Technical Reports Server (NTRS)

    Seiler, M. R.

    1979-01-01

    The development of separation in corners of thrust augmentor wings having Coanda jets was investigated using hot film surface sensors and pressure transducers. Separation on the test augmentor began at a corner very close to the augmentor exit and then rapidly proceeded upstream. Measurements of the pressure fields in the corner region indicated that a modified form of the Stratford criterion could be used to predict the onset of separation. Testing was conducted over a range of nozzle pressure ratios, aspect ratios, diffuser angles, and designs of the boundary layer and Coanda nozzles.

  3. Secondary production of massive quarks in thrust

    NASA Astrophysics Data System (ADS)

    Hoang, André H.; Mateu, Vicent; Pietrulewicz, Piotr

    2016-01-01

    We present a factorization framework that takes into account the production of heavy quarks through gluon splitting in the thrust distribution for e+e- → hadrons. The explicit factorization theorems and some numerical results are displayed in the dijet region where the kinematic scales are widely separated, which can be extended systematically to the whole spectrum. We account for the necessary two-loop matrix elements, threshold corrections, and include resummation up to N3LL order. We include nonperturbative power corrections through a field theoretical shape function, and remove the O(ΛQCD) renormalon in the partonic soft function by appropriate mass-dependent subtractions. Our results hold for any value of the quark mass, from an infinitesimally small (merging to the known massless result) to an infinitely large one (achieving the decoupling limit). This is the first example of an application of a variable flavor number scheme to final state jets.

  4. Small centrifugal pumps for low thrust rockets

    NASA Technical Reports Server (NTRS)

    Gulbrandsen, N. C.; Furst, R. B.; Burgess, R. M.; Scheer, D. D.

    1985-01-01

    This paper presents the results of a combined analytical and experimental investigation of low specific speed pumps for potential use as components of propellant feed systems for low thrust rocket engines. Shrouded impellers and open face impellers were tested in volute type and vaned diffuser type pumps. Full- and partial-emission diffusers and full- and partial-admission impellers were tested. Axial and radial loads, head and efficiency versus flow, and cavitation tests were conducted. Predicted performance of two pumps are compared when pumping water and liquid hydrogen. Detailed pressure loss and parasitic power values are presented for two pump configurations. Partial-emission diffusers were found to permit use of larger impeller and diffuser passages with a minimal performance penalty. Normal manufacturing tolerances were found to result in substantial power requirement variation with only a small pressure rise change. Impeller wear ring leakage was found to reduce pump pressure rise to an increasing degree as the pump flowrate was decreased.

  5. Thrust Production in a Mechanical Swimming Lamprey

    NASA Astrophysics Data System (ADS)

    Leftwich, Megan; Smits, Alexander

    2008-11-01

    To develop a comprehensive model of lamprey locomotion, we use a robotic lamprey as a means of investigating the surface pressure and wake structure during swimming. A programmable microcomputer actuates 11 servomotors that produce a traveling wave along the length of the lamprey body. The waveform is based on the motion of the American eel (Anguilla rostrata), as described by Tytell and Lauder (2004) and kinematic studies of living lamprey. The amplitude of the phase-averaged surface pressure distribution along the centerline of the robot increases toward the tail, which is consistent with previous momentum balance experiments indicating that thrust is produced mainly at the tail. The phase relationship between the pressure signal and the vortex shedding from the tail is also examined. The project is supported by NIH CNRS Grant 1R01NS054271.

  6. Formamide mediated, air-brush printable, indium-free soluble Zn-Sn-O semiconductors for thin-film transistor applications.

    PubMed

    Kim, Seong Jip; Jeon, Hye-Ji; Oh, Sang-Jin; Lee, Sun Sook; Choi, Youngmin; Park, Jin-Seong; Jeong, Sunho

    2014-11-12

    In this study, for high-performance indium-free metal oxide channel layer, we synthesize Zn-Sn-O (ZTO) precursor solutions in which formamide is incorporated as an additive for catalyzing the subsequent sol-gel reactions and the evolution of chemical structure. It is revealed that the formamide plays a critical chemical role in evolving a chemical structure with more oxygen-deficient oxide lattice and with less hydroxide, allowing for high field-effect mobility over 7 cm(2)/V·s. Furthermore, it is for the first time demonstrated that electrically active metal-oxide films can be patterned, using an air-brush printing technique, by directly depositing formamide-mediated ZTO-precursor solutions in patterned geometries. PMID:25333251

  7. Test program to provide confidence in liquid oxygen cooling of hydrocarbon fueled rocket thrust chambers

    NASA Technical Reports Server (NTRS)

    Armstrong, E. S.

    1986-01-01

    An experimental program has been planned at the NASA Lewis Research Center to build confidence in the feasibility of liquid oxygen cooling for hydrocarbon fueled rocket engines. Although liquid oxygen cooling has previously been incorporated in test hardware, more runtime is necessary to gain confidence in this concept. In the previous tests, small oxygen leaks developed at the throat of the thrust chamber and film cooled the hot-gas side of the chamber wall without resulting in catastrophic failure. However, more testing is necessary to demonstrate that a catastrophic failure would not occur if cracks developed further upstream between the injector and the throat, where the boundary layer has not been established. Since under normal conditions cracks are expected to form in the throat region of the thrust chamber, cracks must be initiated artificially in order to control their location. Several methods of crack initiation are discussed in this report. Four thrust chambers, three with cracks and one without, should be tested. The axial location of the cracks should be varied parametrically. Each chamber should be instrumented to determine the effects of the cracks, as well as the overall performance and durability of the chambers.

  8. Kinematics and estimated thrust production of swimming harp and ringed seals.

    PubMed

    Fish, F E; Innes, S; Ronald, K

    1988-07-01

    The propulsive motions of swimming harp seals (Phoca groenlandica Erxleben) and ringed seals (Phoca hispida Schreber) were studied by filming individuals in a flume. The seals swam at velocities ranging from 0.6 to 1.42 m s-1. Locomotion was accomplished with alternate lateral sweeps of the hind flippers generated by lateral flexions of the axial body in conjunction with flexion of the flippers. The frequency of the propulsive cycle increased linearly with the swimming velocity, and the maximum angle of attack of the flipper decreased, but the amplitude remained constant. The kinematics and morphology of this hind flipper motion indicated that phocid seals do not swim in the carangiform mode as categorized by Lighthill (1969), but in a distinct mode that mimics swimming by thunniform propulsors. The hind flippers acted as hydrofoils, and the efficiency, thrust power and coefficient of thrust were calculated from unsteady wing theory. The propulsive efficiency was high at approximately 0.85. The thrust power increased curvilinearly with velocity. The drag coefficient ranged from 0.012 to 0.028 and was found to be 2.8-7.0 times higher than the theoretical minimum. The drag coefficient was high compared with that of phocid seals examined during gliding or towing experiments, indicating an increased drag encumbered by actively swimming seals. It was determined that phocid seals are capable of generating sufficient power for swimming with turbulent boundary layer conditions.

  9. The Chevron Foil Thrust Bearing: Improved Performance Through Passive Thermal Management and Effective Lubricant Mixing

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert

    2013-01-01

    An improved foil thrust bearing is described that eliminates or reduces the need for forced cooling of the bearing foils while at the same time improves the load capacity of the bearing, enhances damping, provides overload tolerance, and eliminates the high speed load capacity drop-off that plagues the current state of the art. The performance improvement demonstrated by the chevron foil thrust bearing stems from a novel trailing edge shape that splays the hot lubricant in the thin film radially, thus preventing hot lubricant carry-over into the ensuing bearing sector. Additionally, the chevron shaped trailing edge induces vortical mixing of the hot lubricant with the gas that is naturally resident within the inter-pad region of a foil thrust bearing. The elimination of hot gas carry-over in combination with the enhanced mixing has enabled a completely passive thermally managed foil bearing design. Laboratory testing at NASA has confirmed the original analysis and reduced this concept to practice.

  10. Surface adsorption of oppositely charged C14TAB-PAMPS mixtures at the air/water interface and the impact on foam film stability.

    PubMed

    Fauser, Heiko; von Klitzing, Regine; Campbell, Richard A

    2015-01-01

    We have studied the oppositely charged polyelectrolyte/surfactant mixture of poly(acrylamidomethylpropanesulfonate) sodium salt (PAMPS) and tetradecyl trimethylammonium bromide (C14TAB) using a combination of neutron reflectivity and ellipsometry measurements. The interfacial composition was determined using three different analysis methods involving the two techniques for the first time. The bulk surfactant concentration was fixed at a modest value while the bulk polyelectrolyte concentration was varied over a wide range. We reveal complex changes in the surface adsorption behavior. Mixtures with low bulk PAMPS concentrations result in the components interacting synergistically in charge neutral layers at the air/water interface. At the bulk composition where PAMPS and C14TAB are mixed in an equimolar charge ratio in the bulk, we observe a dramatic drop in the surfactant surface excess to leave a large excess of polyelectrolyte at the interface, which we infer to have loops in its interfacial structure. Further increase of the bulk PAMPS concentration leads to a more pronounced depletion of material from the surface. Mixtures containing a large excess of PAMPS in the bulk showed enhanced adsorption, which is attributed to the large increase in total ionic strength of the system and screening of the surfactant headgroup charges. The data are compared to our former results on PAMPS/C14TAB mixtures [Kristen et al. J. Phys. Chem. B, 2009, 23, 7986]. A peak in the surface tension is rationalized in terms of the changing surface adsorption and, unlike in more concentrated systems, is unrelated to bulk precipitation. Also, a comparison between the determined interfacial composition with zeta potential and foam film stability data shows that the highest film stability occurs when there is enhanced synergistic adsorption of both components at the interface due to charge screening when the total ionic strength of the system is highest. The additional contribution to the

  11. A magnetic coupling thrust stand for microthrust measurements

    NASA Astrophysics Data System (ADS)

    Wright, W. P.; Ferrer, P.

    2016-01-01

    A direct thrust measurement system that is based on a horizontal lever and utilizes a novel magnetic coupling mechanism to measure thrust has been developed. The system is capable of measuring thrusts as low as 10’s of μN. While zero drift is observed in the balance, tests have shown that they do not have an appreciable effect on thrust measurements. The thrust stand’s sensitivity can be adjusted by shifting the position of the coupling magnet inside the stand’s thrust support member, which allows flexibility for testing both higher and lower powered thrusters. The thrust stand has been modeled theoretically and the predicted results from the model are compared with experimentally measured data. The system was tested using a simple cold gas thruster and provided credible results that can be compared with other systems studied in the literature. Advantages include that the thrust stand is very cheap and easy to construct and further, the calibration process takes no longer than half an hour, facilitating rapid turnaround times while still retaining accuracy. Repeatability tests have shown that the balance gives consistent results.

  12. Thrust augmentation nozzle (TAN) concept for rocket engine booster applications

    NASA Astrophysics Data System (ADS)

    Forde, Scott; Bulman, Mel; Neill, Todd

    2006-07-01

    Aerojet used the patented thrust augmented nozzle (TAN) concept to validate a unique means of increasing sea-level thrust in a liquid rocket booster engine. We have used knowledge gained from hypersonic Scramjet research to inject propellants into the supersonic region of the rocket engine nozzle to significantly increase sea-level thrust without significantly impacting specific impulse. The TAN concept overcomes conventional engine limitations by injecting propellants and combusting in an annular region in the divergent section of the nozzle. This injection of propellants at moderate pressures allows for obtaining high thrust at takeoff without overexpansion thrust losses. The main chamber is operated at a constant pressure while maintaining a constant head rise and flow rate of the main propellant pumps. Recent hot-fire tests have validated the design approach and thrust augmentation ratios. Calculations of nozzle performance and wall pressures were made using computational fluid dynamics analyses with and without thrust augmentation flow, resulting in good agreement between calculated and measured quantities including augmentation thrust. This paper describes the TAN concept, the test setup, test results, and calculation results.

  13. Impact of plasma noise on a direct thrust measurement system

    NASA Astrophysics Data System (ADS)

    Pottinger, S. J.; Lamprou, D.; Knoll, A. K.; Lappas, V. J.

    2012-03-01

    In order to evaluate the accuracy and sensitivity of a pendulum-type thrust measurement system, a linear variable differential transformer (LVDT) and a laser optical displacement sensor have been used simultaneously to determine the displacement resulting from an applied thrust. The LVDT sensor uses an analog interface, whereas the laser sensor uses a digital interface to communicate the displacement readings to the data acquisition equipment. The data collected by both sensors show good agreement for static mass calibrations and validation with a cold gas thruster. However, the data obtained using the LVDT deviate significantly from that of the laser sensor when operating two varieties of plasma thrusters: a radio frequency (RF) driven plasma thruster, and a DC powered plasma thruster. Results establish that even with appropriate shielding and signal filtering the LVDT sensor is subject to plasma noise and radio frequency interactions which result in anomalous thrust readings. Experimental data show that the thrust determined using the LVDT system in a direct current plasma environment and a RF discharge is approximately a factor of three higher than the thrust values obtained using a laser sensor system for the operating conditions investigated. These findings are of significance to the electric propulsion community as LVDT sensors are often utilized in thrust measurement systems and accurate thrust measurement and the reproducibility of thrust data is key to analyzing thruster performance. Methods are proposed to evaluate system susceptibility to plasma noise and an effective filtering scheme presented for DC discharges.

  14. The 30-centimeter ion thrust subsystem design manual

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The principal characteristics of the 30-centimeter ion propulsion thrust subsystem technology that was developed to satisfy the propulsion needs of future planetary and early orbital missions are described. Functional requirements and descriptions, interface and performance requirements, and physical characteristics of the hardware are described at the thrust subsystem, BIMOD engine system, and component level.

  15. Optimal low-thrust, Earth-Moon trajectories

    NASA Astrophysics Data System (ADS)

    Kluever, Craig Allen

    1993-01-01

    A variety of optimal trajectories from a circular low-Earth parking orbit to a circular low-lunar parking orbit are computed for a range of low-thrust spacecraft. The problem is studied in the context of the classical restricted three-body problem. Minimum-fuel, planar trajectories with a fixed thrust-coast-thrust engine sequence are computed for both a 'high-end' low-thrust spacecraft and 'moderate' low-thrust nuclear electric propulsion (NEP) spacecraft. Since a low-thrust trajectory is a long duration transfer with slowly developing spirals about the Earth and Moon, the minimum-fuel Earth-Moon trajectory is obtained by formulating and successively solving a hierarchy of subproblems. The subproblems include optimal Earth-escape and Moon-capture trajectories and sub-optimal translunar trajectories. The complete minimum-fuel trajectory problem is eventually solved using a 'hybrid' direct/indirect method which utilizes the benefits of a direct optimization method and an indirect method from optimal control theory. Minimum-fuel transfers are also computed using a switching function structure which results in multiple thrust and coast arcs. In addition, a new combined vehicle and trajectory optimization problem of maximum payload fraction is formulated and solved. Finally, 3-D minimum-fuel trajectories are obtained for both the 'high-end' and 'moderate' low-thrust spacecraft. Numerical results are presented for various optimal Earth-Moon trajectories.

  16. Heat pipe technology for advanced rocket thrust chambers

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.

    1971-01-01

    The application of heat pipe technology to the design of rocket engine thrust chambers is discussed. Subjects presented are: (1) evaporator wick development, (2) specific heat pipe designs and test results, (3) injector design, fabrication, and cold flow testing, and (4) preliminary thrust chamber design.

  17. Electronics Engineering Department Thrust Area report FY'84

    SciTech Connect

    Minichino, C.; Phelps, P.L.

    1984-01-01

    This report describes the work of the Electronics Engineering Department Thrust Areas for FY'84: diagnostics and microelectronic engineering; signal and control engineering; microwave and pulsed power engineering; computer-aided engineering; engineering modeling and simulation; and systems engineering. For each Thrust Area, an overview and a description of the goals and achievements of each project is provided.

  18. The Star Thrust Experiment, FRC Formation and Sustainment Using RMF

    NASA Astrophysics Data System (ADS)

    Miller, Kenneth; Slough, John

    1998-11-01

    The same qualities that make the FRC attractive as a terrestrial power source make them even more attractive as a fusion engine for space missions due to strict constraints on size, complexity and weight. The first step toward attaining a viable FRC reactor/propulsion unit is the development of a simplified formation process that allows for subsequent sustainment. The Star Thrust Experiment (STX) has been designed to do this using a 50G 330 kHz Rotating Magnetic Field (RMF) for current drive. Two 10 MW solid state supplies (IGBT switched) drive the RMF antennas for milliseconds through a 20:1 99% efficient air core transformer. The 2 m long by 0.35 m radius RMF antennas are the inductors of LC resonant circuits. With Q ~ 60, the square wave IGBT output is filtered into a clean sinusoid, and 60 MW of circulating power is attained. Solenoidal magnets create ~ 1 kG axial confining field in the STX vacuum chamber, a 3 m long by 0.4 m diameter quartz tube. An axial discharge, 100 MW Alfven heater, and confining field reversal are available for plasma ionization and heating. At densities of 10^20 m-3, temperatures of ~ 15 eV are needed for RMF field penetration and effective current drive. Major system development and construction has been completed, and initial operation has begun. Supported by NASA and USDOE.

  19. Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum

    NASA Technical Reports Server (NTRS)

    Brady, David A.; White, Harold G.; March, Paul; Lawrence, James T.; Davies, Frank J.

    2014-01-01

    This paper describes the test campaigns designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma. This paper will not address the physics of the quantum vacuum plasma thruster (QVPT), but instead will describe the recent test campaign. In addition, it contains a brief description of the supporting radio frequency (RF) field analysis, lessons learned, and potential applications of the technology to space exploration missions. During the first (Cannae) portion of the campaign, approximately 40 micronewtons of thrust were observed in an RF resonant cavity test article excited at approximately 935 megahertz and 28 watts. During the subsequent (tapered cavity) portion of the campaign, approximately 91 micronewtons of thrust were observed in an RF resonant cavity test article excited at approximately 1933 megahertz and 17 watts. Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level. Test campaign results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma.

  20. Tectonic Significance of Intraoceanic Thrusts in the Nankai Trough

    NASA Astrophysics Data System (ADS)

    Tsuji, T.; Kodaira, S.; Park, J.; Ashi, J.; Fukao, Y.; Moore, G. F.; Matsuoka, T.

    2009-12-01

    The Nankai Trough is a convergent margin where the Philippine Sea plate is subducting beneath southwest Japan. Because this subduction zone has repeatedly generated great earthquakes with Mw>8, seismic reflection studies have been intensively carried out in the whole Nankai Trough region. However, the role of oceanic crust in plate convergent margins was not well understood. Recently, Tsuji et al. [2009] identified intraoceanic thrusts developed as imbricate structures within the subducting Philippine Sea plate off the Kii Peninsula in central Japan manifesting as strong-amplitude reflections observed in an industry-standard 3D seismic reflection data set. In this study, we use other 2D and 3D seismic reflection data acquired in the whole Nankai Trough region and extract geometries of (1) intraoceanic thrusts, (2) surface of oceanic crust and (3) Moho in order to discuss characteristics of intraoceanic thrusts distributed in the whole Nankai Trough region. We mainly use seismic reflection data acquired by JAMSTEC. Seismic profiles demonstrate that intraoceanic faults are densely distributed eastern side of the Cape Shionomisaki (southern edge of the Kii Peninsula). Large displacements of a few major intraoceanic thrusts elevate the crust surface, and the offset due to cumulative displacements reaches >1 km at the sediment-igneous crust interface. A part of Kashinozaki-Knoll is also uplifted by the thrust displacement. These imbricate intraoceanic thrusts cut through the oceanic crust as a discontinuous thrust plane. The intraoceanic thrusts strike nearly parallel to the trend of the trough axis. However the fault traces are bending at the western termination; the fault planes extend upward from side edges of the underlying intraoceanic thrusts and work as lateral faults. The deformation within oceanic crust may have continued until recently with subduction, because the shallow sediment as well as the seafloor is deformed due to the thrust displacement [Kodaira et

  1. New Highly Dynamic Approach for Thrust Vector Control

    NASA Astrophysics Data System (ADS)

    Hecht, M.; Ettl, J.; Grothe, D.; Hrbud, I.

    2015-09-01

    For a new launcher system a thrust vector control system is needed. This launch vehicle system consists of two rockets which are namely the VS-50 (two-stage suborbital vehicle) and the VLM-1 (three-stage microsatellite launch vehicle). VLM-1 and VS-50 are developed in a cooperation between the German Aerospace Center (DLR) and the Brazilian Aeronautics and Space Institute (IAE). To keep these two rockets on its trajectory during flight a highly dynamic thrust vector control system is required. For the purpose of developing such a highly dynamic thrust vector control system a master thesis was written by the author. The development includes all mechanical constructions as well as control algorithms and electronics design. Moreover an optimization of control algorithms was made to increase the dynamic capabilities of the thrust vector control system. The composition of the right components plus the sophisticated control algorithm make the thrust vector control system highly dynamic.

  2. Thrust Measurements for a Pulse Detonation Engine Driven Ejector

    NASA Technical Reports Server (NTRS)

    Santoro, Robert J.; Pak, Sibtosh; Shehadeh, R.; Saretto, S. R.; Lee, S.-Y.

    2005-01-01

    Results of an experimental effort on pulse detonation driven ejectors aimed at probing different aspects of PDE ejector processes, are presented and discussed. The PDE was operated using ethylene as the fuel and an equimolar oxygen/nitrogen mixture as the oxidizer at an equivalence ratio of one. The thrust measurements for the PDE alone are in excellent agreement with experimental and modeling results reported in the literature and serve as a Baseline for the ejector studies. These thrust measurements were then used as a basis for quantifying thrust augmentation for various PDE/ejector setups using constant diameter ejector tubes and various detonation tube/ejector tube overlap distances. The results show that for the geometries studied here, a maximum thrust augmentation of 24% is achieved. The thrust augmentation results are complemented by shadowgraph imaging of the flowfield in the ejector tube inlet area and high frequency pressure transducer measurements along the length of the ejector tube.

  3. Static thrust recovery of PAR craft on solid surfaces

    NASA Astrophysics Data System (ADS)

    Matveev, K. I.

    2008-08-01

    Power-Augmented-Ram Vehicles belong to a new class of ground-effect machines with hybrid support. Recovered static thrust and static lift on solid surfaces are important amphibious characteristics of this craft. Experimental data for the static thrust recovery and the transition to a hovering mode are obtained in the tests with a vehicle model on two types of ground surface and with variable engine thrust and flap trailing-edge gap. The uphill surface and increased mass of the model demonstrate reductions in thrust recovery. A comparison with a two-dimensional potential-flow theory is presented. The static thrust accumulation, identified in the pre-hovering regime of a model on solid surface, does not significantly benefit the low-speed forward motion.

  4. Surface chemistry and corrosion behavior of aluminum-copper systems: Air-formed films to complex conversion coatings

    NASA Astrophysics Data System (ADS)

    Chidambaram, Devicharan

    Understanding the mechanism of corrosion inhibition by carcinogenic chromates is critical to the development of environmentally safe coatings containing benign chromate substitutes. An integrated approach to correlate the surface chemistry and corrosion behavior of a wide range of systems has been undertaken. Electrochemical behavior was studied by open circuit potential (OCP) measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). Surface chemistry was studied using variable-angle X-ray photoelectron spectroscopy (VAXPS), X-ray absorption near edge spectroscopy (XANES), secondary ion mass spectroscopy (SIMS), infrared spectroscopy and synchrotron infrared micro spectroscopy (SIRMS) and Raman spectroscopy. Using SIRMS, the ASTM recommended acetone degreasing was shown to initiate pitting of AA2024-T3 via photochemical formation of acetic acid. Due to the known tendency for photoreduction of Cr6+(3d0) following soft X-ray dosage during XPS, a novel method has been developed to prevent this reduction. This method yields, for the first time, an accurate determination of the Cr6+ content of a CCC. The pretreatment of the alloy prior to conversion coating has been shown to have significant influence on the surface intermetallic distribution, composition and corrosion resistance of the initial oxide film and subsequent conversion coating. AlconoxRTM pretreatment was found to result in a highly protective surface film that inhibits the subsequent formation of CCC. The study also shows that coupling of the alloy to platinum during the bromate pretreatment increases the corrosion resistance of the subsequently formed CCC by over an order of magnitude due to reduction in surface copper content. Adsorption of chromate ion on the passive oxide film formed on the metal surface was observed to induce fixed negative charges that inhibit chloride ingress on planar surfaces. While deprotonation of the aluminum hydroxide film by chromate was

  5. Interactive property of large thrust sheets with footwall rocks—the Sub thrust interactive duplex hypothesis: A mechanism of dome formation in thrust sheets

    NASA Astrophysics Data System (ADS)

    Hatcher, Robert D.

    1991-06-01

    Recently acquired Appalachian Ultradeep Core Hole (ADCOH) Project site investigation seismic reflection data and geologic data from the Appalachians and several other orogenic belts suggest an important mutually interdependent relationship exists between emplacement of large crystalline thrust sheets and the deforming foreland rocks beneath. This relationship suggests isolated domes beneath crystalline thrust sheets may be produced by passive folding of the sheet as a result of formation of an antiformal stack duplex in the platform sedimentary sequence beneath. Suggestions that domes in crystalline thrust sheets formed by interference of late open folds is doubtlessly still valid in places, but the platform duplex mechanism is probably also valid to explain the late doming of many crystalline and other large thrust sheets. The dome beneath the Shooting Creek and Brasstown Bald windows in the ADCOH site region is imaged as an antiformal stack duplex at depth. The Tallulah Falls dome, Grandfather Mountain and Mountain City windows, and Smokies Foothills duplex in the site region and elsewhere in the southern Blue Ridge are all late isolated domes and all are probably or demonstrably underlain by antiformal stack duplexes beneath the Blue Ridge-Piedmont composite crystalline thrust sheet. The Assynt window and footwall duplex benath the Arnabol and Moine thrusts in Scotland, and the Engadine window in the Alps may be similar structures.

  6. Thin films under chemical stress

    SciTech Connect

    Not Available

    1991-01-01

    The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

  7. An optical spot test for the detection of dopamine in human urine using stabilized in air lipid films.

    PubMed

    Nikolelis, Dimitrios P; Drivelos, Dimitrios A; Simantiraki, Maria G; Koinis, Spyros

    2004-04-15

    The present technique describes a simple, sensitive spot test for the rapid one-shot detection of dopamine in human urine using lipid films with incorporated resorcin[4]arene receptor that are synthesized by a chemical reaction with a methacrylate polymer on a glass fiber filter. The lipid films without the receptor provided fluorescence under a UV lamp. The use of the receptor in these films quenched this fluorescence, and the color became similar to that of the filters without the lipid films. A drop of dopamine or urine containing this stimulant provided a "switching on" of the fluorescence, which allows the rapid detection of this stimulant in human urine at 10(-8) M concentrations. The novelty of the present work is that it opens new routes in the field of biosensing, i.e., development of sensitive, rapid, and simple methods for detecting species based on the fluorescence of the lipid membranes on a polymer film, and provides a spot test technique for the rapid detection of dopamine. The effect of potent interferences including a wide range of compounds usually found in human urine (i.e., ascorbic aid, glucose, leucine, glycine, tartrate, citrate, bicarbonate, and caffeine) was examined using an aqueous buffered solution that contained the potent interference and dopamine at two lower concentration levels (i.e., 3 x 10(-8)-10(-8) M). The effect of proteins and lipids was also investigated at these two lower dopamine concentration levels in aqueous buffered solution. The results showed no interferences from all these constituents at concentrations usually found in human urine samples; for example, albumin up to 3.22 g/L concentration levels did not provide any interference (i.e., no fluorescence). A drop of urine containing this stimulant provided similar results, i.e., a "switching on" of the fluorescence that allows a technique for the rapid detection of this stimulant in human urine at 10(-8) M concentrations. The technique is not based on a calibration

  8. Initial Thrust Measurements of Marshall's Ion-ioN Thruster

    NASA Technical Reports Server (NTRS)

    Caruso, Natalie R. S.; Scogin, Tyler; Liu, Thomas M.; Walker, Mitchell L. R.; Polzin, Kurt A.; Dankanich, John W.

    2015-01-01

    Electronegative ion thrusters are a variation of traditional gridded ion thruster technology differentiated by the production and acceleration of both positive and negative ions. Benefits of electronegative ion thrusters include the elimination of lifetime-limiting cathodes from the thruster architecture and the ability to generate appreciable thrust from both charge species. While much progress has been made in the development of electronegative ion thruster technology, direct thrust measurements are required to unambiguously demonstrate the efficacy of the concept and support continued development. In the present work, direct thrust measurements of the thrust produced by the MINT (Marshall's Ion-ioN Thruster) are performed using an inverted-pendulum thrust stand in the High-Power Electric Propulsion Laboratory's Vacuum Test Facility-1 at the Georgia Institute of Technology with operating pressures ranging from 4.8 x 10(exp -5) and 5.7 x 10(exp -5) torr. Thrust is recorded while operating with a propellant volumetric mixture ratio of 5:1 argon to nitrogen with total volumetric flow rates of 6, 12, and 24 sccm (0.17, 0.34, and 0.68 mg/s). Plasma is generated using a helical antenna at 13.56 MHz and radio frequency (RF) power levels of 150 and 350 W. The acceleration grid assembly is operated using both sinusoidal and square waveform biases of +/-350 V at frequencies of 4, 10, 25, 125, and 225 kHz. Thrust is recorded for two separate thruster configurations: with and without the magnetic filter. No thrust is discernable during thruster operation without the magnetic filter for any volumetric flow rate, RF forward Power level, or acceleration grid biasing scheme. For the full thruster configuration, with the magnetic filter installed, a brief burst of thrust of approximately 3.75 mN +/- 3 mN of error is observed at the start of grid operation for a volumetric flow rate of 24 sccm at 350 W RF power using a sinusoidal waveform grid bias at 125 kHz and +/- 350 V

  9. Convective Heat Transfer with and without Film Cooling in High Temperature, Fuel Rich and Lean Environments

    NASA Astrophysics Data System (ADS)

    Greiner, Nathan J.

    Modern turbine engines require high turbine inlet temperatures and pressures to maximize thermal efficiency. Increasing the turbine inlet temperature drives higher heat loads on the turbine surfaces. In addition, increasing pressure ratio increases the turbine coolant temperature such that the ability to remove heat decreases. As a result, highly effective external film cooling is required to reduce the heat transfer to turbine surfaces. Testing of film cooling on engine hardware at engine temperatures and pressures can be exceedingly difficult and expensive. Thus, modern studies of film cooling are often performed at near ambient conditions. However, these studies are missing an important aspect in their characterization of film cooling effectiveness. Namely, they do not model effect of thermal property variations that occur within the boundary and film cooling layers at engine conditions. Also, turbine surfaces can experience significant radiative heat transfer that is not trivial to estimate analytically. The present research first computationally examines the effect of large temperature variations on a turbulent boundary layer. Subsequently, a method to model the effect of large temperature variations within a turbulent boundary layer in an environment coupled with significant radiative heat transfer is proposed and experimentally validated. Next, a method to scale turbine cooling from ambient to engine conditions via non-dimensional matching is developed computationally and the experimentally validated at combustion temperatures. Increasing engine efficiency and thrust to weight ratio demands have driven increased combustor fuel-air ratios. Increased fuel-air ratios increase the possibility of unburned fuel species entering the turbine. Alternatively, advanced ultra-compact combustor designs have been proposed to decrease combustor length, increase thrust, or generate power for directed energy weapons. However, the ultra-compact combustor design requires a

  10. Sandbox modelling of sequential thrusting in a mechanically two-layered system and its implications in fold-and-thrust belts

    NASA Astrophysics Data System (ADS)

    Saha, Puspendu; Bose, Santanu; Mandal, Nibir

    2016-10-01

    Many fold-and-thrust belts display multi-storied thrust sequences, characterizing a composite architecture of the thrust wedges. Despite dramatic progress in sandbox modelling over the last three decades, our understanding of such composite thrust-wedge mechanics is limited and demands a re-visit to the problem of sequential thrusting in mechanically layered systems. This study offers a new approach to sandbox modelling, designed with a two-layered sandpack simulating a mechanically weak Coulomb layer, resting coherently upon a stronger Coulomb layer. Our experimental models reproduce strikingly similar styles of the multi-storied frontal thrust sequences observed in natural fold-and- thrust belts. The upper weak horizon undergoes sequential thrusting at a high spatial frequency, forming numerous, closely spaced frontal thrusts, whereas the lower strong horizon produces widely spaced thrusts with progressive horizontal shortening. This contrasting thrust progression behaviour gives rise to composite thrust architecture in the layered sandpack. We show the evolution of such composite thrust sequences as a function of frictional strength (μb) at the basal detachment and thickness ratio (Tr) between the weak and strong layers. For any given values of Tr and μb, the two thrust sequences progress at different rates; the closely-spaced, upper thrust sequence advances forelandward at a faster rate than the widely-spaced, lower thrust sequence. Basal friction (μb) has little effects on the vergence of thrusts in the upper weak layer; they verge always towards foreland, irrespective of Tr values. But, the lower strong layer develops back-vergent thrusts when μb is low (∼0.36). In our experiments, closely spaced thrusts in the upper sequence experience intense reactivation due to their interaction with widely spaced thrusts in the lower sequence. The interaction eventually affects the wedge topography, leading to two distinct parts: inner and outer wedges

  11. Lift and thrust generation by a butterfly-like 3D flapping wing model

    NASA Astrophysics Data System (ADS)

    Suzuki, Kosuke; Inamuro, Takaji

    2013-11-01

    The flapping flight of tiny insects such as a butterfly is of fundamental interest not only in biology itself but also in its practical use for the development of micro air vehicles. It is known that a butterfly flaps downward for generating lift force and backward for generating thrust force. In this study, we consider a simple butterfly-like 3D flapping wing model whose body is a thin rod, wings are rigid and rectangular, and wing motion is simplified. We investigate the lift and thrust generation by the butterfly-like flapping wing model by using the immersed boundary-lattice Boltzmann method. Firstly, we compute the lift and thrust forces when the body of the model is fixed for Reynolds numbers in the range of 50 - 1000. In addition, we evaluate the supportable mass for each Reynolds number by using the computed lift force. Secondly, we simulate the free flight where the body can move translationally but cannot rotate. As results, we find that the evaluated supportable mass can be supported even in the free flight, and the wing model with the mass and the Reynolds number of a fruit fly can go upward against the gravity. Finally, we simulate the effect of the rotation of the body. As results, we find that the body has a large pitching motion and consequently gets off-balance.

  12. Deployable Engine Air Brake

    NASA Technical Reports Server (NTRS)

    2014-01-01

    On approach, next-generation aircraft are likely to have airframe noise levels that are comparable to or in excess of engine noise. ATA Engineering, Inc. (ATA) is developing a novel quiet engine air brake (EAB), a device that generates "equivalent drag" within the engine through stream thrust reduction by creating a swirling outflow in the turbofan exhaust nozzle. Two Phase II projects were conducted to mature this technology: (1) a concept development program (CDP) and (2) a system development program (SDP).

  13. Multibeam study of the Flores Backarc Thrust Belt, Indonesia

    NASA Astrophysics Data System (ADS)

    Silver, Eli A.; Breen, Nancy A.; Prasetyo, Hardi; Hussong, Donald M.

    1986-03-01

    Using the SeaMARC II seafloor mapping tool in conjunction with closely spaced seismic reflection profiles, we have mapped a segment of the Flores back arc thrust zone. Structural irregularities along the deformation front of the thrust zone result from changing stratigraphy and basement structure of the lower plate. NE trending faults cutting the outer slope of the Flores basin are easily mapped because they truncate dense drainage patterns obliquely. Mud diapirs, probably indicating elevated fluid pressures, have formed throughout the accretionary wedge but appear to be concentrated (as do back arc thrust earthquakes) at the ends of thrust faults. The overall orientation of the deformation front of the accretionary wedge is 100°, suggesting a NNE sense of thrust motion and supporting an origin of the thrust zone by collision of the arc with Australia rather than by magmatic forcing or gravitational sliding or spreading. Orientations of faults and folds close to the arc are not consistent with the trends of the frontal thrusts, however, and the difference may be due to either different initial orientations or to later rotations of structural features as the accretionary wedge grew.

  14. Thrust Stand Characterization of the NASA Evolutionary Xenon Thruster (NEXT)

    NASA Technical Reports Server (NTRS)

    Diamant, Kevin D.; Pollard, James E.; Crofton, Mark W.; Patterson, Michael J.; Soulas, George C.

    2010-01-01

    Direct thrust measurements have been made on the NASA Evolutionary Xenon Thruster (NEXT) ion engine using a standard pendulum style thrust stand constructed specifically for this application. Values have been obtained for the full 40-level throttle table, as well as for a few off-nominal operating conditions. Measurements differ from the nominal NASA throttle table 10 (TT10) values by 3.1 percent at most, while at 30 throttle levels (TLs) the difference is less than 2.0 percent. When measurements are compared to TT10 values that have been corrected using ion beam current density and charge state data obtained at The Aerospace Corporation, they differ by 1.2 percent at most, and by 1.0 percent or less at 37 TLs. Thrust correction factors calculated from direct thrust measurements and from The Aerospace Corporation s plume data agree to within measurement error for all but one TL. Thrust due to cold flow and "discharge only" operation has been measured, and analytical expressions are presented which accurately predict thrust based on thermal thrust generation mechanisms.

  15. Structural style of the Marathon thrust belt, West Texas

    NASA Astrophysics Data System (ADS)

    Hickman, Robert G.; Varga, Robert J.; Altany, Robert M.

    2009-09-01

    The Marathon portion of the Ouachita thrust belt consists of a highly deformed allochthonous wedge of Cambrian-Pennsylvanian slope strata (Marathon facies) that was transported to the northwest and emplaced over Pennsylvanian foredeep sediments. The foredeep strata in turn overlie early-middle Paleozoic shelfal sediments which are deformed by late Paleozoic basement-involved reverse faults. The Dugout Creek thrust is the basal thrust of the allochthon. Shortening in this sheet and overlying sheets is ˜80%. Steep imbricate faults link the Dugout Creek thrust to upper level detachments forming complex duplex zones. Progressive thrusting and shortening within the allochthon folded the upper level detachments and associated thrust sheets. The Caballos Novaculite is the most competent unit within the Marathon facies and controlled development of prominent detachment folds. Deeper imbricate sheets composed of the Late Pennsylvanian foredeep strata, and possibly early-middle Paleozoic shelfal sediments developed concurrently with emplacement of the Marathon allochthon and folded the overlying allochthon. Following termination of thrusting in the earliest Permian, subsidence and deposition shifted northward to the Delaware, Midland and Val Verde foreland basins.

  16. Interseismic coupling on the main Himalayan thrust

    NASA Astrophysics Data System (ADS)

    Stevens, V. L.; Avouac, J. P.

    2015-07-01

    We determine the slip rate and pattern of interseismic coupling on the Main Himalayan Thrust along the entire Himalayan arc based on a compilation of geodetic, interferometric synthetic aperture radar, and microseismicity data. We show that convergence is perpendicular to the arc and increases eastwards from 13.3 ± 1.7 mm/yr to 21.2 ± 2.0 mm/yr. These rates are comparable to geological and geomorphic estimates, indicating an essentially elastic geodetic surface strain. The interseismic uplift rate predicted from the coupling model closely mimics the topography, suggesting that a small percentage of the interseismic strain is permanent. We find that the fault is fully locked along its complete length over about 100 km width. We don't find any resolvable aseismic barrier that could affect the seismic segmentation of the arc and limit the along-strike propagation of seismic ruptures. The moment deficit builds up at a rate of 15.1 ± 1 × 1019 N m/yr for the entire length of the Himalaya.

  17. Cretaceous biostratigraphy in the Wyoming thrust belt.

    USGS Publications Warehouse

    Nichols, D.J.; Jacobson, S.R.

    1982-01-01

    In the Cretaceous section of the thrust belt, fossils are especially useful for dating and correlating repetitive facies of different ages in structurally complex terrain. The biostratigraphic zonation for the region is based on megafossils (chiefly ammonites) , which permit accurate dating and correlation of outcrop sections, and which have been calibrated with the radiometric time scale for the Western Interior. Molluscan and vertebrate zone fossils are difficult to obtain from the subsurface, however, and ammonites are restricted to rocks of marine origin. Palynomorphs (plant microfossils) have proven to be the most valuable fossils in the subsurface because they can be recovered from drill cuttings. Palynomorphs also are found in both marine and nonmarine rocks and can be used for correlation between facies. Stratigraphic ranges of selected Cretaceous marine and nonmarine palynomorphs in previously designated reference sections in Fossil Basin, Wyoming are correlated with the occurrence of ammonites and other zone fossils in the same sections. These correlations can be related to known isotopic ages, and they contribute to the calibration of palynomorph ranges in the Cretaceous of the Western Interior. -from Authors

  18. Electronegative Gas Thruster - Direct Thrust Measurement Project

    NASA Technical Reports Server (NTRS)

    Dankanich, John (Principal Investigator); Aanesland, Ane; Polzin, Kurt; Walker, Mitchell

    2015-01-01

    This effort is an international collaboration and academic partnership to mature an innovative electric propulsion (EP) thruster concept to TRL 3 through direct thrust measurement. The initial target application is for Small Satellites, but can be extended to higher power. The Plasma propulsion with Electronegative GASES (PEGASES) concept simplifies ion thruster operation, eliminates a neutralizer requirement and should yield longer life capabilities and lower cost implementation over conventional gridded ion engines. The basic proof-of concept has been demonstrated and matured to TRL 2 over the past several years by researchers at the Laboratoire de Physique des Plasma in France. Due to the low maturity of the innovation, there are currently no domestic investments in electronegative gas thrusters anywhere within NASA, industry or academia. The end product of this Center Innovation Fund (CIF) project will be a validation of the proof-of-concept, maturation to TRL 3 and technology assessment report to summarize the potential for the PEGASES concept to supplant the incumbent technology. Information exchange with the foreign national will be one-way with the exception of the test results. Those test results will first go through a standard public release ITAR/export control review, and the results will be presented in a public technical forum, and the results will be presented in a public technical forum.

  19. Propeller thrust analysis using Prandtl's lifting line theory, a comparison between the experimental thrust and the thrust predicted by Prandtl's lifting line theory

    NASA Astrophysics Data System (ADS)

    Kesler, Steven R.

    The lifting line theory was first developed by Prandtl and was used primarily on analysis of airplane wings. Though the theory is about one hundred years old, it is still used in the initial calculations to find the lift of a wing. The question that guided this thesis was, "How close does Prandtl's lifting line theory predict the thrust of a propeller?" In order to answer this question, an experiment was designed that measured the thrust of a propeller for different speeds. The measured thrust was compared to what the theory predicted. In order to do this experiment and analysis, a propeller needed to be used. A walnut wood ultralight propeller was chosen that had a 1.30 meter (51 inches) length from tip to tip. In this thesis, Prandtl's lifting line theory was modified to account for the different incoming velocity depending on the radial position of the airfoil. A modified equation was used to reflect these differences. A working code was developed based on this modified equation. A testing rig was built that allowed the propeller to be rotated at high speeds while measuring the thrust. During testing, the rotational speed of the propeller ranged from 13-43 rotations per second. The thrust from the propeller was measured at different speeds and ranged from 16-33 Newton's. The test data were then compared to the theoretical results obtained from the lifting line code. A plot in Chapter 5 (the results section) shows the theoretical vs. actual thrust for different rotational speeds. The theory over predicted the actual thrust of the propeller. Depending on the rotational speed, the error was: at low speeds 36%, at low to moderate speeds 84%, and at high speeds the error increased to 195%. Different reasons for these errors are discussed.

  20. Computational Study of Surface Tension and Wall Adhesion Effects on an Oil Film Flow Underneath an Air Boundary Layer

    NASA Technical Reports Server (NTRS)

    Celic, Alan; Zilliac, Gregory G.

    1998-01-01

    The fringe-imaging skin friction (FISF) technique, which was originally developed by D. J. Monson and G. G. Mateer at Ames Research Center and recently extended to 3-D flows, is the most accurate skin friction measurement technique currently available. The principle of this technique is that the skin friction at a point on an aerodynamic surface can be determined by measuring the time-rate-of-change of the thickness of an oil drop placed on the surface under the influence of the external air boundary layer. Lubrication theory is used to relate the oil-patch thickness variation to shear stress. The uncertainty of FISF measurements is estimated to be as low as 4 percent, yet little is known about the effects of surface tension and wall adhesion forces on the measured results. A modified version of the free-surface Navier-Stokes solver RIPPLE, developed at Los Alamos National Laboratories, was used to compute the time development of an oil drop on a surface under a simulated air boundary layer. RIPPLE uses the volume of fluid method to track the surface and the continuum surface force approach to model surface tension and wall adhesion effects. The development of an oil drop, over a time period of approximately 4 seconds, was studied. Under the influence of shear imposed by an air boundary layer, the computed profile of the drop rapidly changes from its initial circular-arc shape to a wedge-like shape. Comparison of the time-varying oil-thickness distributions computed using RIPPLE and also computed using a greatly simplified numerical model of an oil drop equation which does not include surface tension and wall adhesion effects) was used to evaluate the effects of surface tension on FISF measurement results. The effects of surface tension were found to be small but not necessarily negligible in some cases.

  1. Thrust stand for high-power electric propulsion devices

    NASA Astrophysics Data System (ADS)

    Haag, T. W.

    1991-05-01

    A thrust stand for use with magnetoplasmadynamic (MPD) thrusters operated at powers up to 250 kW steady state has been built and tested. The stand was based on an inverted pendulum configuration which resulted in large displacements and high resolution. Up to 50 mm of deflection was observed under a force of 5 N. This large range of displacement significantly reduced the effects of facility induced vibrations on thrust measurements. A remotely operated system was provided for in situ calibration of the thrust stand prior to and immediately after data were obtained. Calibrations showed that thrust measurements were linear and repeatable to within a fraction of 1%. Structural distortions of the vacuum facility due to pumpdown were detected with an inclinometer located in the thrust stand base. Slope deviations as small as 10 arcsec could be compensated using a remotely controlled leveling motor. Early problems with magnetically induced tares caused by the thruster discharge current were reduced by rerouting high-current cables to decrease stray fields. Tares due to discharge current were on the order of 26 mN at 3000 A, and those due to an applied field current were 63 mN at 1400 A. The thrust stand was used with a water-cooled, applied field, steady-state MPD device at power levels up to 125 kW. Hot thruster firings as long as 1 h were performed. By precisely maintaining a level thrust stand base, thermal drift was held to about 2% of the full scale reading over this period. The remaining thermal drift could be subtracted from the thrust measurement to further reduce systematic error. Tares caused by the applied magnetic field were similarly removed. By subtracting tabulated discharge current magnetic tares, thrust measurement uncertainty was reduced to approximately 2% of the measured value.

  2. Electric sail control mode for amplified transverse thrust

    NASA Astrophysics Data System (ADS)

    Toivanen, P.; Janhunen, P.; Envall, J.

    2015-01-01

    The electric solar wind sail produces thrust by centrifugally spanned high voltage tethers interacting with the solar wind protons. The sail attitude can be controlled and attitude maneuvers are possible by tether voltage modulation synchronous with the sail rotation. Especially, the sail can be inclined with respect to the solar wind direction to obtain transverse thrust to change the osculating orbit angular momentum. Such an inclination has to be maintained by a continual control voltage modulation. Consequently, the tether voltage available for the thrust is less than the maximum voltage provided by the power system. Using a spherical pendulum as a model for a single rotating tether, we derive analytical estimations for the control efficiency for two separate sail control modes. One is a continuous control modulation that corresponds to strictly planar tether tip motion. The other is an on-off modulation with the tether tip moving along a closed loop on a saddle surface. The novel on-off mode is introduced here to both amplify the transverse thrust and reduce the power consumption. During the rotation cycle, the maximum voltage is applied to the tether only over two thrusting arcs when most of the transverse thrust is produced. In addition to the transverse thrust, we obtain the thrusting angle and electric power consumption for the two control modes. It is concluded that while the thrusting angle is about half of the sail inclination for the continuous modulation it approximately equals to the inclination angle for the on-off modulation. The efficiency of the on-off mode is emphasized when power consumption is considered, and the on-off mode can be used to improve the propulsive acceleration through the reduced power system mass.

  3. Powered Descent Guidance with General Thrust-Pointing Constraints

    NASA Technical Reports Server (NTRS)

    Carson, John M., III; Acikmese, Behcet; Blackmore, Lars

    2013-01-01

    The Powered Descent Guidance (PDG) algorithm and software for generating Mars pinpoint or precision landing guidance profiles has been enhanced to incorporate thrust-pointing constraints. Pointing constraints would typically be needed for onboard sensor and navigation systems that have specific field-of-view requirements to generate valid ground proximity and terrain-relative state measurements. The original PDG algorithm was designed to enforce both control and state constraints, including maximum and minimum thrust bounds, avoidance of the ground or descent within a glide slope cone, and maximum speed limits. The thrust-bound and thrust-pointing constraints within PDG are non-convex, which in general requires nonlinear optimization methods to generate solutions. The short duration of Mars powered descent requires guaranteed PDG convergence to a solution within a finite time; however, nonlinear optimization methods have no guarantees of convergence to the global optimal or convergence within finite computation time. A lossless convexification developed for the original PDG algorithm relaxed the non-convex thrust bound constraints. This relaxation was theoretically proven to provide valid and optimal solutions for the original, non-convex problem within a convex framework. As with the thrust bound constraint, a relaxation of the thrust-pointing constraint also provides a lossless convexification that ensures the enhanced relaxed PDG algorithm remains convex and retains validity for the original nonconvex problem. The enhanced PDG algorithm provides guidance profiles for pinpoint and precision landing that minimize fuel usage, minimize landing error to the target, and ensure satisfaction of all position and control constraints, including thrust bounds and now thrust-pointing constraints.

  4. Role of detachments and thrust kinematics in Structural evolution of Kohat and Potwar fold thrust belt in Pakistan

    NASA Astrophysics Data System (ADS)

    Ghani, Humaad; Zeilinger, Gerold; Sobel, Edward; Heidarzadeh, Ghasem

    2016-04-01

    The Kohat and Potwar fold thrust belts in Pakistan represent the outermost external zone of the Himalayan fold and thrust system. The Main Boundary thrust marks their northern extent, showing that they are genetically linked; however, both exhibit a distinct contrast between the structural style at the surface and subsurface. This contrast becomes more conspicuous at the leading edge of the thrust belt where the Potwar allochothon extends further south, linked to Kohat in the north via an active strike-slip fault. Previous workers explained the structural evolution of the two belts separately, disregarding the influence of similar fold and thrusts developed in both belts. This research focuses on the preparation of a 3D structural model at the boundary of the two thrust belts to understand similarities and differences in their structural style and evolution. The model is constrained by integrating field, seismic and well data for better subsurface interpretation. Cross sections show that Potwar evolved on thrust faults originating from a basal detachment in Precambrian (pC) salt and terminating in Miocene Molasse forming duplexes of pre Himalayan strata. To the south, the Potwar allochothon is glided over a salt detachment with rare internal deformation toward its leading edge, forming fault bend fold thrust structure known as Salt range. The structural evolution towards the west in Kohat results from deformation on multiple detachment horizons at the pC salt, Eocene evaporites and Miocene Molasse. Disharmonic folding over Eocene evaporites is evident from their presence in the cores of outcropping folds. In the subsurface, closely spaced thrusts cut up section from basal detachment terminates in Eocene evaporites forming duplex in northern part of area. In south change of lithological facies from evaporites to limestone shift detachment level upward in to molasse strata which resemble structural style in northern Potwar. Thrusts at the surface evolved from the

  5. Managing Momentum on the Dawn Low Thrust Mission

    NASA Technical Reports Server (NTRS)

    Smith, Brett A.; Vanelli, Charles A.; Swenka, Edward R.

    2009-01-01

    Dawn is low-thrust interplanetary spacecraft enroute to the asteroids Vesta and Ceres in an effort to better understand the early creation of the solar system. After launch in September 2007, the spacecraft will flyby Mars in February 2009 before arriving at Vesta in summer of 2011 and Ceres in early 2015. Three solar electric ion-propulsion engines are used to provide the primary thrust for the Dawn spacecraft. Ion engines produce a very small but very efficient force, and therefore must be thrusting almost continuously to realize the necessary change in velocity to reach Vesta and Ceres.

  6. Multiphysics Thrust Chamber Modeling for Nuclear Thermal Propulsion

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; Cheng, Gary; Chen, Yen-Sen

    2006-01-01

    The objective of this effort is to develop an efficient and accurate thermo-fluid computational methodology to predict environments for a solid-core, nuclear thermal engine thrust chamber. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation. A two-pronged approach is employed in this effort: A detailed thermo-fluid analysis on a multi-channel flow element for mid-section corrosion investigation; and a global modeling of the thrust chamber to understand the effect of heat transfer on thrust performance. Preliminary results on both aspects are presented.

  7. Flapping tail membrane in bats produces potentially important thrust during horizontal takeoffs and very slow flight.

    PubMed

    Adams, Rick A; Snode, Emily R; Shaw, Jason B

    2012-01-01

    Historically, studies concerning bat flight have focused primarily on the wings. By analyzing high-speed video taken on 48 individuals of five species of vespertilionid bats, we show that the capacity to flap the tail-membrane (uropatagium) in order to generate thrust and lift during takeoffs and minimal-speed flight (<1 m (s-1)) was largely underestimated. Indeed, bats flapped the tail-membrane by extensive dorso-ventral fanning motions covering as much as 135 degrees of arc consistent with thrust generation by air displacement. The degree of dorsal extension of the tail-membrane, and thus the potential amount of thrust generated during platform launches, was significantly correlated with body mass (P = 0.02). Adduction of the hind limbs during upstrokes collapsed the tail-membrane thereby reducing its surface area and minimizing negative lift forces. Abduction of the hind limbs during the downstroke fully expanded the tail-membrane as it was swept ventrally. The flapping kinematics of the tail-membrane is thus consistent with expectations for an airfoil. Timing offsets between the wings and tail-membrane during downstrokes was as much as 50%, suggesting that the tail-membrane was providing thrust and perhaps lift when the wings were retracting through the upstoke phase of the wing-beat cycle. The extent to which the tail-membrane was used during takeoffs differed significantly among four vespertilionid species (P = 0.01) and aligned with predictions derived from bat ecomorphology. The extensive fanning motion of the tail membrane by vespertilionid bats has not been reported for other flying vertebrates.

  8. Flapping Tail Membrane in Bats Produces Potentially Important Thrust during Horizontal Takeoffs and Very Slow Flight

    PubMed Central

    Adams, Rick A.; Snode, Emily R.; Shaw, Jason B.

    2012-01-01

    Historically, studies concerning bat flight have focused primarily on the wings. By analyzing high-speed video taken on 48 individuals of five species of vespertilionid bats, we show that the capacity to flap the tail-membrane (uropatagium) in order to generate thrust and lift during takeoffs and minimal-speed flight (<1 m s−1) was largely underestimated. Indeed, bats flapped the tail-membrane by extensive dorso-ventral fanning motions covering as much as 135 degrees of arc consistent with thrust generation by air displacement. The degree of dorsal extension of the tail-membrane, and thus the potential amount of thrust generated during platform launches, was significantly correlated with body mass (P = 0.02). Adduction of the hind limbs during upstrokes collapsed the tail-membrane thereby reducing its surface area and minimizing negative lift forces. Abduction of the hind limbs during the downstroke fully expanded the tail-membrane as it was swept ventrally. The flapping kinematics of the tail-membrane is thus consistent with expectations for an airfoil. Timing offsets between the wings and tail-membrane during downstrokes was as much as 50%, suggesting that the tail-membrane was providing thrust and perhaps lift when the wings were retracting through the upstoke phase of the wing-beat cycle. The extent to which the tail-membrane was used during takeoffs differed significantly among four vespertilionid species (P = 0.01) and aligned with predictions derived from bat ecomorphology. The extensive fanning motion of the tail membrane by vespertilionid bats has not been reported for other flying vertebrates. PMID:22393378

  9. Characteristics of thrust fault imbrication near the frontal edge of the Blue Ridge thrust sheet, Buffalo Mountain, Tennessee

    SciTech Connect

    Duddy, M.M.; Woodward, N.B.

    1985-01-01

    The Buffalo Mountain thrust sheet, located along the western margin of the Blue Ridge in northeastern Tennessee, provides an excellent opportunity to examine transitional structural styles and deformation mechanisms between the Valley and Ridge and Blue Ridge. Previous interpretation suggests that, because of pre-fault tilting, thrust faults within the Buffalo Mountain complex cut down stratigraphic section. Geometric data from the present study indicate, however, that the thrust faults cut up section with stratigraphic separations of up to 16,500'. Footwall and hanging wall bedding orientations reveal a stair-step thrust geometry; the Unicoi Fm. (basal Chilhowee Gp. quartzite) is a hanging wall flat, and the Knox Gp. (Cambro-Ordovician carbonate) is a footwall ramp. Ductile and brittle deformation mechanisms are represented by mesofabric elements. Important deformation mechanisms and elements include: flexural slip and flexural flow folding styles, pressure solution cleavage, extensional and contractional fractures, quartz filled tensional fractures and cataclastic fault zones. Although previous workers have determined that thrusting within the Blue Ridge occurs in an out-of-sequence pattern, the Buffalo Mountain thrust complex provides an example of in-sequence thrusting. Thus, based on this example, deformation styles and mechanisms within the Blue Ridge appear to be similar to Valley and Ridge deformation styles and mechanisms.

  10. Interplay of thrust, back-thrust, strike-slip and salt tectonics in a fold and thrust belt system: an example from Zakynthos Island, Greece

    NASA Astrophysics Data System (ADS)

    Zelilidis, A.; Papatheodorou, G.; Maravelis, A. G.; Christodoulou, D.; Tserolas, P.; Fakiris, E.; Dimas, X.; Georgiou, N.; Ferentinos, G.

    2016-10-01

    The southwestern flank of the Hellenic fold and thrust belt, situated along the southern edge of the Dinarides-Albanides-Hellenides continental convergent zone, was examined for reconstructing the tectonic deformation. This investigation presents an integrated study of onshore sedimentological and structural analyses, as well as offshore seismic lines, across the Pliocene-Pleistocene sedimentary succession in Zakynthos Island. Back-thrust faults, using the Triassic evaporites as decollement surface, during the Pliocene, and coeval diapiric intrusions formed three sub-basins on the hangingwall of the Kalamaki back-thrust fault. This interaction is responsible for the growth of the Skopos Mountain and the soft sediment deformation that formed synclines and slumps, respectively. Back-thrust and strike-slip faults were active during the early Pleistocene, and diapiric intrusions modified the bathymetry on the sea floor, giving rise to slumps and recumbent folds. At least five events of synsedimentary diapiric intrusions have been recognized and are marked by five slump horizons. During the Holocene, the diapiric intrusions between the Kalamaki back-thrust and the Vrachionas anticline could be either related to normal faults or gravitationally driven.

  11. Fabrication and different photoelectric responses of nanocrystalline ZnO film irradiated with UV and white light in dry air

    NASA Astrophysics Data System (ADS)

    Zou, Zhijun; Qiu, Yang; Xie, Changsheng; Xu, Jingjing; Luo, Yongsong; Wang, Chunlei; Yan, Hailong

    2015-09-01

    In this paper, nanocrystalline ZnO film with porous structure was successfully prepared on alumina substrate by the technology of screen printing and the subsequent heat treatment. The fundamental characteristics of the as-prepared sample were examined through XRD, FE-SEM, EDX and PL spectra measurements. Meanwhile, photoelectric responses of it were tested under UV and white light irradiation, respectively. Different photocurrent curves were obtained. Under UV light, the photocurrent with comparatively high amplitude of each cycle could mostly recover upon the light off. While for white light, the photocurrent with low amplitude just partially recovered when the light was turned off. This phenomenon indicated that, after the white light off, a large number of free electrons still remained within the materials. To calculate the amount of the remained free electrons, three photocurrent parameters, which are related to the density of free electrons in ZnO, were defined for the first time. Furthermore, the explanations for the different photoelectric responses of ZnO based on the double Schottky barrier model were also proposed.

  12. The Development of NASA's Low Thrust Trajectory Tool Set

    NASA Technical Reports Server (NTRS)

    Sims, Jon; Artis, Gwen; Kos, Larry

    2006-01-01

    Highly efficient electric propulsion systems can enable interesting classes of missions; unfortunately, they provide only a limited amount of thrust. Low-thrust (LT) trajectories are much more difficult to design than impulsive-type (chemical propulsion) trajectories. Previous low-thrust (LT) trajectory optimization software was often difficult to use, often had difficulties converging, and was somewhat limited in the types of missions it could support. A new state-of-the-art suite (toolbox) of low-thrust (LT) tools along with improved algorithms and methods was developed by NASA's MSFC, JPL, JSC, and GRC to address the needs of our customers to help foster technology development in the areas of advanced LT propulsion systems, and to facilitate generation of similar results by different analysts.

  13. Development of pneumatic thrust-deflecting powered-lift systems

    NASA Technical Reports Server (NTRS)

    Englar, R. J.; Nichols, J. H., Jr.; Harris, M. J.; Eppel, J. C.; Shovlin, M. D.

    1986-01-01

    Improvements introduced into the Circulation Control Wing/Upper Surface Blowing (CCW/USB) STOL concept (Harris et al., 1982) are described along with results of the full-scale static ground tests and model-scale wind tunnel investigations. Tests performed on the full-scale pneumatic thrust-deflecting system installed on the NASA QSRA aircraft have demonstrated that, relative to the original baseline configuration, a doubling of incremental thrust deflection due to blowing resulted from improvements that increased the blowing span and momentum, as well as from variations in blowing slot height and geometry of the trailing edge. A CCW/Over the Wing model has been built and tested, which was shown to be equivalent to the CCW/USB system in terms of pneumatic thrust deflection and lift generation, while resolving the problem of cruise thrust loss due to exhaust scrubbing on the wing upper surface.

  14. Fourth Programme Cycle in Population Education Addresses New Thrusts.

    ERIC Educational Resources Information Center

    Population Education Newsletter and Forum, 1987

    1987-01-01

    Discusses the developments of the Regional Population Education Program of the Unesco Principal Regional Office for Asia and the Pacific during the period 1984-87. Discusses new projects, technical assistance activities, national capabilities, and new program thrusts. (TW)

  15. Low-thrust solar electric propulsion navigation simulation program

    NASA Technical Reports Server (NTRS)

    Hagar, H. J.; Eller, T. J.

    1973-01-01

    An interplanetary low-thrust, solar electric propulsion mission simulation program suitable for navigation studies is presented. The mathematical models for trajectory simulation, error compensation, and tracking motion are described. The languages, input-output procedures, and subroutines are included.

  16. Style and timing of frontal structures, thrust belt, Central Utah

    SciTech Connect

    Lawton, T.F.

    1985-07-01

    The Cordilleran fold and thrust belt in central Utah may be divided into a western belt of Precambrian to lower Mesozoic strata shortened above ramp-style thrust faults and an eastern belt of folded middle to upper Mesozoic rocks. Shortening in the eastern foldbelt occurred above a bedding-plane thrust fault system that terminates within a thick section of Jurassic shale, siltstone, and anhydrite. Demonstrable synthrusting deposits within the region are late Early to Late Cretaceous in age. The age of synorogenic deposits and structural relations of postorogenic strata indicate that deformation was complete by the close of the Cretaceous or early Paleocene, and support a thrust mechanism for much of the folding in the region.

  17. A lifting surface theory for thrust augmenting ejectors

    NASA Technical Reports Server (NTRS)

    Bevilaqua, P. M.

    1977-01-01

    The circulation theory of airfoil lift has been applied to calculate the performance of thrust augmenting ejectors. The ejector shroud is considered to be 'flying' in the secondary velocity field induced by the entrainment of the primary jet, so that the augmenting thrust is viewed as analogous to the lift on an airfoil. Vortex lattice methods are utilized to compute the thrust augmentation from the force on the flaps. The augmentation is shown to be a function of the length and shape of the flaps, as well as their position and orientation. Predictions of this new theory are compared with the results of classical methods of calculating the augmentation by integration of the stream thrust.

  18. Control-Volume Analysis Of Thrust-Augmenting Ejectors

    NASA Technical Reports Server (NTRS)

    Drummond, Colin K.

    1990-01-01

    New method of analysis of transient flow in thrust-augmenting ejector based on control-volume formulation of governing equations. Considered as potential elements of propulsion subsystems of short-takeoff/vertical-landing airplanes.

  19. Aerodynamics of thrust vectoring by Navier-Stokes solutions

    NASA Technical Reports Server (NTRS)

    Tseng, Jing-Biau; Lan, C. Edward

    1991-01-01

    Induced aerodynamics from thrust vectoring are investigated by a computational fluid dynamic method. A thin-layer Reynolds-averaged Navier-Stokes code with multiblock capability is used. Jet properties are specified on the nozzle exit plane to simulate the jet momentum. Results for a rectangular jet in a cross flow are compared with data to verify the code. Further verification of the calculation is made by comparing the numerical results with transonic data for a wing-body combination. Additional calculations were performed to elucidate the following thrust vectoring effects: the thrust vectoring effect on shock and expansion waves, induced effects on nearby surfaces, and the thrust vectoring effect on the leading edge vortex.

  20. A double pendulum plasma thrust balance and thrust measurement at a tandem mirror exhaust

    NASA Astrophysics Data System (ADS)

    Yang, T. F.; Liu, Ping; Chang-Díaz, F. R.; Lander, Harvey; Childs, R. A.; Becker, H. D.; Fairfax, S. A.

    1995-09-01

    For the purpose of measuring the plasma momentum flux in a plasma system, a highly sensitive and precision balance has been developed. It can measure a force, an impulse, or thrust as low as 0.1 mN free of mechanical noise, electrical and magnetic pickups. The double pendulum system consists of two parallel conducting plates. One or both of the plates can be suspended by needles. The needle suspended plate (or plates) can swing freely with negligible friction because of the sharp points of the needles. When one of the plates is impacted by an impulse it will swing relatively to the fixed plate or other movable plate. The capacitance between the plates changes as a result of such a motion. The change of capacitance as a function of time is recorded as an oscillating voltage signal. The amplitude of such a voltage signal is proportional to the impacting force or impulse. The proportional factor can be calibrated. The forces can thus be read out from the recorded value of the voltage. The equation of motion for the pendulum system has been solved analytically. The circuit equation for the electronic measurement system has been formulated and solved numerically. Using this balance the thrust at the exhaust of a Tandem Mirror plasma thruster has been measured. The analytical solution of the overall characteristics agrees greatly with the measurement.

  1. A double pendulum plasma thrust balance and thrust measurement at a tandem mirror exhaust

    SciTech Connect

    Yang, T.F.; Liu, P.; Chang-Diaz, F.R.; Lander, H.; Childs, R.A.; Becker, H.D.; Fairfax, S.A.

    1995-09-01

    For the purpose of measuring the plasma momentum flux in a plasma system, a highly sensitive and precision balance has been developed. It can measure a force, an impulse, or thrust as low as 0.1 mN free of mechanical noise, electrical and magnetic pickups. The double pendulum system consists of two parallel conducting plates. One or both of the plates can be suspended by needles. The needle suspended plate (or plates) can swing freely with negligible friction because of the sharp points of the needles. When one of the plates is impacted by an impulse it will swing relatively to the fixed plate or other movable plate. The capacitance between the plates changes as a result of such a motion. The change of capacitance as a function of time is recorded as an oscillating voltage signal. The amplitude of such a voltage signal is proportional to the impacting force or impulse. The proportional factor can be calibrated. The forces can thus be read out from the recorded value of the voltage. The equation of motion for the pendulum system has been solved analytically. The circuit equation for the electronic measurement system has been formulated and solved numerically. Using this balance the thrust at the exhaust of a Tandem Mirror plasma thruster has been measured. The analytical solution of the overall characteristics agrees greatly with the measurement. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  2. Lower extremity thrust and non-thrust joint mobilization for patellofemoral pain syndrome: a case report

    PubMed Central

    Simpson, Brad G; Simon, Corey B

    2014-01-01

    A 40-year old female presented to physical therapy with a one-year history of insidious right anteromedial and anterolateral knee pain. Additionally, the patient had a history of multiple lateral ankle sprains bilaterally, the last sprain occurring on the right ankle 1 year prior to the onset of knee pain. The patient was evaluated and given a physical therapy diagnosis of patellofemoral pain syndrome (PFPS), with associated talocrural and tibiofemoral joint hypomobility limiting ankle dorsiflexion and knee extension, respectively. Treatment included a high-velocity low amplitude thrust manipulation to the talocrural joint, which helped restore normal ankle dorsiflexion range of motion. The patient also received tibiofemoral joint non-thrust manual therapy to regain normal knee extension mobility prior to implementing further functional progression exercises to her home program (HEP). This case report highlights the importance of a detailed evaluation of knee and ankle joint mobility in patients presenting with anterior knee pain. Further, manual physical therapy to the lower extremity was found to be successful in restoring normal movement patterns and pain-free function in a patient with chronic anterior knee pain. PMID:24976753

  3. Acoustically shielded exhaust system for high thrust jet engines

    NASA Technical Reports Server (NTRS)

    Carey, John P. (Inventor); Lee, Robert (Inventor); Majjigi, Rudramuni K. (Inventor)

    1995-01-01

    A flade exhaust nozzle for a high thrust jet engine is configured to form an acoustic shield around the core engine exhaust flowstream while supplementing engine thrust during all flight conditions, particularly during takeoff. The flade airflow is converted from an annular 360.degree. flowstream to an arcuate flowstream extending around the lower half of the core engine exhaust flowstream so as to suppress exhaust noise directed at the surrounding community.

  4. Recent advances in low-thrust propulsion technology

    NASA Technical Reports Server (NTRS)

    Stone, James R.

    1988-01-01

    The NASA low-thrust propulsion technology program is aimed at providing high performance options to a broad class of near-term and future missions. Major emphases of the program are on storable and hydrogen/oxygen low-thrust chemical, low-power (auxiliary) electrothermal, and high-power electric propulsion. This paper represents the major accomplishments of the program and discusses their impact.

  5. The Selection of Propellers for High Thrust at Low Airspeed

    NASA Technical Reports Server (NTRS)

    Conway, Robert N.; Biermann, David

    1941-01-01

    Problem of improving thrust at low speeds is primarily one of reducing angle of attack of operation of sections to improve L/D or reducing blade helix angle. An analysis, based on recent propeller data, is presented for determining improvements in thrust or efficiency which could be obtained by increased number of blades, increased blade width, increased diameter, dual rotation, and two-speed gearing. All methods were found very effective, particularly two-speed gearing.

  6. Development of sputtered high temperature coatings for thrust chambers

    NASA Technical Reports Server (NTRS)

    Busch, R.; Bayne, M. A.

    1976-01-01

    Adherent insulating coatings were developed for thrust chamber service. The coatings consisted of nickel and a ceramic, and were graded in composition from pure nickel at the thrust chamber wall to pure ceramic at the coating surface. The coatings were deposited by rf sputtering from a target with a reversed composition gradient, which was produced by plasma spraying powder mixtures. The effect of deposition parameters on coating characteristics and adherence is discussed.

  7. Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum

    NASA Technical Reports Server (NTRS)

    Brady, David; White, Harold G.; March, Paul; Lawrence, James T.; Davies, Frank J.

    2014-01-01

    This paper describes the eight-day August 2013 test campaign designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma. This paper will not address the physics of the quantum vacuum plasma thruster, but instead will describe the test integration, test operations, and the results obtained from the test campaign. Approximately 30-50 micro-Newtons of thrust were recorded from an electric propulsion test article consisting primarily of a radio frequency (RF) resonant cavity excited at approximately 935 megahertz. Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level, within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure. Several different test configurations were used, including two different test articles as well as a reversal of the test article orientation. In addition, the test article was replaced by an RF load to verify that the force was not being generated by effects not associated with the test article. The two test articles were designed by Cannae LLC of Doylestown, Pennsylvania. The torsion pendulum was designed, built, and operated by Eagleworks Laboratories at the NASA Johnson Space Center of Houston, Texas. Approximately six days of test integration were required, followed by two days of test operations, during which, technical issues were discovered and resolved. Integration of the two test articles and their supporting equipment was performed in an iterative fashion between the test bench and the vacuum chamber. In other words, the test article was tested on the bench, then moved to the chamber, then moved back as needed to resolve issues. Manual frequency control was required throughout the test. Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not

  8. Structural styles of the High Atlas mountains, Morocco: Potential hydrocarbon traps in the footwall of thrusts developed from the reactivation of syn-rift normal faults

    SciTech Connect

    Beauchamp, W.; Allmendinger, R.W.; Barazangi, M. )

    1996-01-01

    Large asymmetrical folds and box folds created by fault bend and fault propagation folding characterize the style of deformation in the High Atlas mountains. Several compressional phases of faulting and folding from the Lower Jurassic through Cenozoic indicate a long and varied tectonic origin for the High Atlas intracontinental mountain belt. Footwall shortcut faults are formed with the inversion of syn-rift listric: normal faults, and progress into low angle thrust faults with fault bend fold geometries. This style of deformation is illustrated on reprocessed seismic reflection data and confirmed by field mapping. Geological field mapping, air photographs, and Thematic Mapper imagery provide important constraints for the interpretation of seismic reflection profiles along the margins of the High Atlas mountains. Balanced cross sections across the High Atlas suggest large horizontal displacements along low angle thrust faults. These thrusts place massive Lower Jurassic carbonates above post-rift Upper Cretaceous and Tertiary rocks. Refolding of thrusts and large scale regional folds indicate oblique slip deformation during and after the inversion of syn-rift normal faults. Low angle thrusts propagate along detachments in shales and marts of the Lower Jurassic. Lower Jurassic shales provide an excellent seal for potential sandstone reservoirs in the Middle Jurassic and Triassic sandstones in the footwall of thrusts.

  9. Wind tunnel test of model target thrust reversers for the Pratt and Whitney aircraft JT8D-100 series engines installed on a 727-200 airplane

    NASA Technical Reports Server (NTRS)

    Hambly, D.

    1974-01-01

    The results of a low speed wind tunnel test of 0.046 scale model target thrust reversers installed on a 727-200 model airplane are presented. The full airplane model was mounted on a force balance, except for the nacelles and thrust reversers, which were independently mounted and isolated from it. The installation had the capability of simulating the inlet airflows and of supplying the correct proportions of primary and secondary air to the nozzles. The objectives of the test were to assess the compatibility of the thrust reversers target door design with the engine and airplane. The following measurements were made: hot gas ingestion at the nacelle inlets; model lift, drag, and pitching moment; hot gas impingement on the airplane structure; and qualitative assessment of the rudder effectiveness. The major parameters controlling hot gas ingestion were found to be thrust reverser orientation, engine power setting, and the lip height of the bottom thrust reverser doors on the side nacelles. The thrust reversers tended to increase the model lift, decrease the drag, and decrease the pitching moment.

  10. Structural styles of the High Atlas mountains, Morocco: Potential hydrocarbon traps in the footwall of thrusts developed from the reactivation of syn-rift normal faults

    SciTech Connect

    Beauchamp, W.; Allmendinger, R.W.; Barazangi, M.

    1996-12-31

    Large asymmetrical folds and box folds created by fault bend and fault propagation folding characterize the style of deformation in the High Atlas mountains. Several compressional phases of faulting and folding from the Lower Jurassic through Cenozoic indicate a long and varied tectonic origin for the High Atlas intracontinental mountain belt. Footwall shortcut faults are formed with the inversion of syn-rift listric: normal faults, and progress into low angle thrust faults with fault bend fold geometries. This style of deformation is illustrated on reprocessed seismic reflection data and confirmed by field mapping. Geological field mapping, air photographs, and Thematic Mapper imagery provide important constraints for the interpretation of seismic reflection profiles along the margins of the High Atlas mountains. Balanced cross sections across the High Atlas suggest large horizontal displacements along low angle thrust faults. These thrusts place massive Lower Jurassic carbonates above post-rift Upper Cretaceous and Tertiary rocks. Refolding of thrusts and large scale regional folds indicate oblique slip deformation during and after the inversion of syn-rift normal faults. Low angle thrusts propagate along detachments in shales and marts of the Lower Jurassic. Lower Jurassic shales provide an excellent seal for potential sandstone reservoirs in the Middle Jurassic and Triassic sandstones in the footwall of thrusts.

  11. Development of a Thrust Stand to Meet LISA Mission Requirements

    NASA Technical Reports Server (NTRS)

    Willis, William D., III; Zakrzwski, Charles M.; Merkowitz, Stephen M.

    2002-01-01

    A thrust stand has been built to measure the force-noise produced by electrostatic micro-Newton (muN) thrusters. The LISA mission's Disturbance Reduction System (DRS) requires thrusters that are capable of producing continuous thrust levels between 1-100 muN with a resolution of 0.1 muN. The stationary force-noise produced by these thrusters must not exceed 0.1 muN/dHz in the measurement bandwidth 10(exp -4) to 1 Hz. The LISA Thrust Stand (LTS) is a torsion-balance type thrust stand designed to meet the following requirements: stationary force-noise measurements from l0( -4) to 1 Hz with 0.1 muN/dHz sensitivity, absolute thrust measurements from 1-100 muN with better than 0.1 muN resolution, and dynamic thruster response from to 10 Hz. The LTS employs a unique vertical configuration, autocollimator for angular position measurements, and electrostatic actuators that are used for dynamic pendulum control and null-mode measurements. Force-noise levels are measured indirectly by characterizing the thrust stand as a spring-mass system. The LTS was initially designed to test the indium FEEP thruster developed by the Austrian Research Center in Seibersdorf (ARCS), but can be modified for testing other thrusters of this type.

  12. Thrust Stand for Vertically Oriented Electric Propulsion Performance Evaluation

    NASA Technical Reports Server (NTRS)

    Moeller, Trevor; Polzin, Kurt A.

    2010-01-01

    A variation of a hanging pendulum thrust stand capable of measuring the performance of an electric thruster operating in the vertical orientation is presented. The vertical orientation of the thruster dictates that the thruster must be horizontally offset from the pendulum pivot arm, necessitating the use of a counterweight system to provide a neutrally-stable system. Motion of the pendulum arm is transferred through a balance mechanism to a secondary arm on which deflection is measured. A non-contact light-based transducer is used to measure displacement of the secondary beam. The members experience very little friction, rotating on twisting torsional pivots with oscillatory motion attenuated by a passive, eddy current damper. Displacement is calibrated using an in situ thrust calibration system. Thermal management and self-leveling systems are incorporated to mitigate thermal and mechanical drifts. Gravitational restoring force and torsional spring constants associated with flexure pivots provide restoring moments. An analysis of the design indicates that the thrust measurement range spans roughly four decades, with the stand capable of measuring thrust up to 12 N for a 200 kg thruster and up to approximately 800 mN for a 10 kg thruster. Data obtained from calibration tests performed using a 26.8 lbm simulated thruster indicated a resolution of 1 mN on 100 mN-level thrusts, while those tests conducted on 200 lbm thruster yielded a resolution of roughly 2.5 micro at thrust levels of 0.5 N and greater.

  13. Polyphase thrust tectonic in the Barberton greenstone belt

    NASA Technical Reports Server (NTRS)

    Paris, I. A.

    1986-01-01

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

  14. Superposed fold-thrust events at the Nevada Test Site

    USGS Publications Warehouse

    Cashman, Patricia H.; Cole, James C.; Trexler, James H.

    2000-01-01

    The Nevada Test Site (NTS), in southern Nye County, Nevada, straddles significant pre-Tertiary structural and stratigraphic boundaries. Detailed stratigraphy and biostratigraphy of the Upper Paleozoic section delineates the regional trust sheets and constrains their burial histories. The Paleozoic rocks record three phases of contractional deformation, overprinted by strike-slip faulting. These occured in the folloing order: (1) foreland-vergant folding and imbricate thrusting in the footwall of the Belted Range thrust; (2) hinterland-vergent folding and thrusting; and (3) north-vergant folding that we interpret as footwall deformation below a third major thrust system. Sinistral slip, typically accompanied by minor east-west shortening, has occured along a series of north-northeast--north-northwest--striking faults around Yucca Flat. This strike-slip faulting postdates both foreland-vergent and hinterland-vergent deformation, and predates the Cretaceous Climax stock; its age relative to the north-vergent folding and thrusting is unknown. Our new understanding of the geometry of these structures provides new insights into the correlation and interpretation of regional structural features. Field trip stops will examine: (1) the stratigraphic differences that allow us to distinguish the regional thrust sheets and constrain their burial histories; and (2) the field relationships that document the kinematics and relative ages of the penetrative deformational events.

  15. Momentum Flux Measurements Using an Impact Thrust Stand

    NASA Technical Reports Server (NTRS)

    Chavers, Greg; Chang-Diaz, Franklin; Breizman, Boris; Bengtson, Roger

    2004-01-01

    A device has been developed to measure the force caused by a beam of charged and neutral particles impacting a target plate. This device, an impact thrust stand, was developed to allow thrusters, during early stages of development, to be quickly and easily exhausted and compared to other thrusters. Since some thruster concepts are tested using laboratory equipment that is heavy and cumbersome, measuring the momentum flux of the particles in the plume can be much simpler than placing the entire thruster on a thrust stand. Conservation of momentum requires the momentum flux measured in the plume to be related to the thrust produced by the thruster. The impact thrust stand was designed to be placed in the plume of an electric thruster and has been tested and compared to the thrust measured from a Hall thruster placed on a pendulum thrust stand. Force measurements taken at several axial locations in the magnetic nozzle region of the Variable Specific Impulse Magnetoplasma Rocket will be presented.

  16. Thrust stand for vertically oriented electric propulsion performance evaluation

    SciTech Connect

    Moeller, Trevor; Polzin, Kurt A.

    2010-11-15

    A variation of a hanging pendulum thrust stand capable of measuring the performance of an electric thruster operating in the vertical orientation is presented. The vertical orientation of the thruster dictates that the thruster must be horizontally offset from the pendulum pivot arm, necessitating the use of a counterweight system to provide a neutrally stable system. Motion of the pendulum arm is transferred through a balance mechanism to a secondary arm on which deflection is measured. A noncontact light-based transducer is used to measure displacement of the secondary beam. The members experience very little friction, rotating on twisting torsional pivots with oscillatory motion attenuated by a passive, eddy-current damper. Displacement is calibrated using an in situ thrust calibration system. Thermal management and self-leveling systems are incorporated to mitigate thermal and mechanical drifts. Gravitational force and torsional spring constants associated with flexure pivots provide restoring moments. An analysis of the design indicates that the thrust measurement range spans roughly four decades, with the stand capable of measuring thrust up to 12 N for a 200 kg thruster and up to approximately 800 mN for a 10 kg thruster. Data obtained from calibration tests performed using a 26.8 lbm simulated thruster indicated a resolution of 1 mN on 100 mN level thrusts, while those tests conducted on a 200 lbm thruster yielded a resolution of roughly 2.5 mN at thrust levels of 0.5 N and greater.

  17. Full Flight Envelope Direct Thrust Measurement on a Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Conners, Timothy R.; Sims, Robert L.

    1998-01-01

    Direct thrust measurement using strain gages offers advantages over analytically-based thrust calculation methods. For flight test applications, the direct measurement method typically uses a simpler sensor arrangement and minimal data processing compared to analytical techniques, which normally require costly engine modeling and multisensor arrangements throughout the engine. Conversely, direct thrust measurement has historically produced less than desirable accuracy because of difficulty in mounting and calibrating the strain gages and the inability to account for secondary forces that influence the thrust reading at the engine mounts. Consequently, the strain-gage technique has normally been used for simple engine arrangements and primarily in the subsonic speed range. This paper presents the results of a strain gage-based direct thrust-measurement technique developed by the NASA Dryden Flight Research Center and successfully applied to the full flight envelope of an F-15 aircraft powered by two F100-PW-229 turbofan engines. Measurements have been obtained at quasi-steady-state operating conditions at maximum non-augmented and maximum augmented power throughout the altitude range of the vehicle and to a maximum speed of Mach 2.0 and are compared against results from two analytically-based thrust calculation methods. The strain-gage installation and calibration processes are also described.

  18. Application of Chaboche Model in Rocket Thrust Chamber Analysis

    NASA Astrophysics Data System (ADS)

    Asraff, Ahmedul Kabir; Suresh Babu, Sheela; Babu, Aneena; Eapen, Reeba

    2015-12-01

    Liquid Propellant Rocket Engines are commonly used in space technology. Thrust chamber is one of the most important subsystems of a rocket engine. The thrust chamber generates propulsive thrust force for flight of the rocket by ejection of combustion products at supersonic speeds. Often double walled construction is employed for these chambers. The thrust chamber investigated here has its hot inner wall fabricated out of a high thermal conductive material like copper alloy and outer wall made of stainless steel. Inner wall is subjected to high thermal and pressure loads during operation of engine due to which it will be in the plastic regime. Main reasons for the failure of such chambers are fatigue in the plastic range (called as low cycle fatigue since the number of cycles to failure will be low in plastic range), creep and thermal ratcheting. Elasto plastic material models are required to simulate the above effects through a cyclic stress analysis. This paper gives the details of cyclic stress analysis carried out for the thrust chamber using different plasticity model combinations available in ANSYS (Version 15) FE code. The best model among the above is applied in the cyclic stress analysis of two dimensional (plane strain and axisymmetric) and three dimensional finite element models of thrust chamber. Cyclic life of the chamber is calculated from stress-strain graph obtained from above analyses.

  19. Thrusting and wedge growth, Southern Alps of Lombardia (Italy)

    NASA Astrophysics Data System (ADS)

    Roeder, Dietrich

    1992-06-01

    A south-vergent fold-thrust belt of Miocene-Recent age accompanies the south slope of the Lombardian Alps and is partly buried beneath Plio-Pleistocene Po Valley basin fill. The belt is probably detached along a trans-crustal thrust, named Main South Alpine Thrust (MSAT), with an estimated dip slip of 70-100 km. Transport on this thrust piggybacks the Adamello pluton of Late Eocene age, pre-Adamello folds, and Oligocene-Miocene Insubric strike-slip structures, by ramping up through 12-15 km of Austro-Alpine (Adria) crust and through 8-10 km of Triassic to Eocene sediments. Folds in the Front Ranges are ascribed to MSAT ramping, not to pre-Adamello compression. The MSAT soles upward in a blind thrust beneath 3-4 km of Oligocene-Pliocene foredeep fill. Initial regional failure along the MSAT implies substantial and pre-existing topographic relief near the Insubric line. An average of 25% wedge thickening during MSAT transport is consistent with the requirement of Coulomb critical taper. Progression of the south-Alpine detachment from the MSAT to the base of the foreland sediments has added a thickness of 6-12 km in footwall imbrications to the base and the toe of the thrust wedge. This addition in wedge volume is consistent with wedge dynamics only if a mid-Miocene or younger spike of excess Alpine topography is admitted.

  20. Structure, optical, and electrical properties of indium tin oxide thin films prepared by sputtering at room temperature and annealed in air or nitrogen

    SciTech Connect

    Guillen, C.; Herrero, J.

    2007-04-01

    Indium tin oxide (ITO) thin films have been grown onto soda-lime glass substrates by sputtering at room temperature with various oxygen to argon partial pressure ratios. After deposition, the samples have been annealed at temperatures ranging from 100 to 500 degree sign C in nitrogen or in air. The structure, optical, and electrical characteristics of the ITO coatings have been analyzed as a function of the deposition and the annealing parameters by x-ray diffraction, spectrophotometry, and Hall effect measurements. It has been found that the as-grown amorphous layers crystallize in the cubic structure by heating above 200 degree sign C. Simultaneously, the visible optical transmittance increases and the electrical resistance decreases, in proportions that depend mainly on the sputtering conditions. The lowest resistivity values have been obtained by annealing at 400 degree sign C in nitrogen, where the highest carrier concentrations are achieved, related to oxygen vacancy creation. Some relationships between the analyzed properties have been established, showing the dependence of the cubic lattice distortion and the infrared optical characteristics on the carrier concentration.

  1. Evolution of the Puente Hills Thrust Fault

    NASA Astrophysics Data System (ADS)

    Bergen, K. J.; Shaw, J. H.; Dolan, J. F.

    2013-12-01

    This study aims to assess the evolution of the blind Puente Hills thrust fault system (PHT) by determining its age of initiation, lateral propagation history, and changes in slip rate over time. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. The PHT is comprised of three fault segments: the Los Angeles (LA), Santa Fe Springs (SFS), and Coyote Hills (CH). The LA and SFS segments are characterized by growth stratigraphy where folds formed by uplift on the fault segments have been continually buried by sediment from the Los Angeles and San Gabriel rivers. The CH segment has developed topography and is characterized by onlapping growth stratigraphy. This depositional setting gives us the unique opportunity to measure uplift on the LA and SFS fault segments, and minimum uplift on the CH fault segment, as the difference in sediment thicknesses across the buried folds. We utilize depth converted oil industry seismic reflection data to image the fold geometries. Identifying time-correlative stratigraphic markers for slip rate determination in the basin has been a problem for researchers in the past, however, as the faunal assemblages observed in wells are time-transgressive by nature. To overcome this, we utilize the sequence stratigraphic model and well picks of Ponti et al. (2007) as a basis for mapping time-correlative sequence boundaries throughout our industry seismic reflection data from the present to the Pleistocene. From the Pleistocene to Miocene we identify additional sequence boundaries in our seismic reflection data from imaged sequence geometries and by correlating industry well formation tops. The sequence and formation top picks are then used to build 3-dimensional surfaces in the modeling program Gocad. From these surfaces we measure the change in thicknesses across the folds to obtain uplift rates between each sequence boundary. Our results show three distinct phases of

  2. Electromagnetic launch, then lessening chemical thrust over time as laser beam powered ion thrust grows{emdash}to any orbit

    SciTech Connect

    Morse, T.M.

    1996-03-01

    The ElectroMagnetic (EM) Launch Tube (LT), using High-Temp SuperConduction (HTSC) EM launch coils if developed, will be built in a tall building, or, if not, at a steep angle up the west slope of an extinct volcano. The Reusable Launch Vehicle (RLV) exits the LT at such high velocity that the otherwise violent entry into the atmosphere is made possible by Special-Laser-Launch-Assist (SLLA), which ionizes and expands the atmosphere immediately ahead of the RLV. At first a brief period of chemical thrust is followed by a long period of ion thrust during ascent to orbit. As decades pass and greater ion thrust is developed, the period of chemical thrust shortens until it is no longer needed. The RLV{close_quote}s ion thrusters are powered by laser/maser, beamed first from the launch site, then from two large Solar-Power-Satellites (SPS) 180{degree} apart in Medium Earth Orbit (MEO) orbit. In orbit, the RLV is limited in where it can go only by the amount of propellant it carries or is stored in various orbits. The RLV can land at a launch site on Earth by using both chemical and ion thrust at first, and later by ion thrust alone as developments cause a far lighter RLV to carry no chemical engines/fuel/tanks. {copyright} {ital 1996 American Institute of Physics.}

  3. Ionic Liquid Films at the Water-Air Interface: Langmuir Isotherms of Tetra-alkylphosphonium-Based Ionic Liquids.

    PubMed

    Shimizu, Karina; Canongia Lopes, José N; Gonçalves da Silva, Amélia M P S

    2015-08-01

    The behavior of ionic liquids trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide and trihexyl(tetradecyl)phosphonium dicyanamide, [P6 6 6 14][Ntf2] and [P6 6 6 14][N(CN)2], respectively, at the water-air interface was investigated using the Langmuir trough technique. The obtained surface pressure versus mean molecular area (MMA) isotherms, π-A, and surface potential versus MMA isotherms, ΔV-A, show distinct interfacial behavior between the two systems. The results were interpreted at a molecular level using molecular dynamics simulations: the different compression regimes along the [P6 6 6 14][Ntf2] isotherm correspond to the self-organization of the ions at the water surface into compact and planar monolayers that coalesce at an MMA value of ca. 1.85 nm(2)/ion pair to form an expanded liquidlike layer. Upon further compression, the monolayer collapses at around 1.2 nm(2)/ion pair to yield a progressively thicker and less organized layer. These transitions are much more subdued in the [P6 6 6 14][N(CN)2] system because of the more hydrophilic nature of the dicyanamide anion. The numerical density profiles obtained from the MD simulation trajectories are also able to emphasize the very unusual packing of the four long alkyl side chains of the cation above and below the ionic layer that forms at the water surface. Such a distribution is also different for the two studied systems during the different compression regimes.

  4. Underwater thrust and power generation using flexible piezoelectric composites: an experimental investigation toward self-powered swimmer-sensor platforms

    NASA Astrophysics Data System (ADS)

    Erturk, Alper; Delporte, Ghislain

    2011-12-01

    Fiber-based flexible piezoelectric composites offer several advantages to use in energy harvesting and biomimetic locomotion. These advantages include ease of application, high power density, effective bending actuation, silent operation over a range of frequencies, and light weight. Piezoelectric materials exhibit the well-known direct and converse piezoelectric effects. The direct piezoelectric effect has received growing attention for low-power generation to use in wireless electronic applications while the converse piezoelectric effect constitutes an alternative to replace the conventional actuators used in biomimetic locomotion. In this paper, underwater thrust and electricity generation are investigated experimentally by focusing on biomimetic structures with macro-fiber composite piezoelectrics. Fish-like bimorph configurations with and without a passive caudal fin (tail) are fabricated and compared. The favorable effect of having a passive caudal fin on the frequency bandwidth is reported. The presence of a passive caudal fin is observed to bring the second bending mode close to the first one, yielding a wideband behavior in thrust generation. The same smart fish configuration is tested for underwater piezoelectric power generation in response to harmonic excitation from its head. Resonant piezohydroelastic actuation is reported to generate milli-newton level hydrodynamic thrust using milli-watt level actuation power input. The average actuation power requirement for generating a mean thrust of 19 mN at 6 Hz using a 10 g piezoelastic fish with a caudal fin is measured as 120 mW. This work also discusses the feasibility of thrust generation using the harvested energy toward enabling self-powered swimmer-sensor platforms with comparisons based on the capacity levels of structural thin-film battery layers as well as harvested solar and vibrational energy.

  5. Exoskeletal Engine Concept: Feasibility Studies for Medium and Small Thrust Engines

    NASA Technical Reports Server (NTRS)

    Halliwell, Ian

    2001-01-01

    The exoskeletal engine concept is one in which the shafts and disks are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Omission of the shafts and disks leads to an open channel at the engine centerline. This has immense potential for reduced jet noise and for the accommodation of an alternative form of thruster for use in a combined cycle. The use of ceramic composite materials has the potential for significantly reduced weight as well as higher working temperatures without cooling air. The exoskeletal configuration is also a natural stepping-stone to complete counter-rotating turbomachinery. Ultimately this will lead to reductions in weight, length, parts count and improved efficiency. The feasibility studies are in three parts. Part 1: Systems and Component Requirements addressed the mechanical aspects of components from a functionality perspective. This effort laid the groundwork for preliminary design studies. Although important, it is not felt to be particularly original, and has therefore not been included in the current overview. Part 2: Preliminary Design Studies turned to some of the cycle and performance issues inherent in an exoskeletal configuration and some initial attempts at preliminary design of turbomachinery were described. Twin-spoon and single-spool 25,800-lbf-thrust turbofans were used as reference vehicles in a mid-size commercial subsonic category in addition to a single-spool 5,000-lbf-thrust turbofan that represented a general aviation application. The exoskeletal engine, with its open centerline, has tremendous potential for noise suppression and some preliminary analysis was done which began to quantify the benefits. Part 3: Additional Preliminary Design Studies revisited the design of single-spool 25,800-lbf-thrust turbofan configurations, but in addition to the original FPR = 1.6 and BPR = 5.1 reference engine. two additional configurations used FPR = 2.4 and BPR = 3.0 and FPR = 3.2 and

  6. Exoskeletal Engine Concept: Feasibility Studies for Medium and Small Thrust Engines

    NASA Technical Reports Server (NTRS)

    Halliwell, Ian

    2001-01-01

    The exoskeletal engine concept is one in which the shafts and disks are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Omission of the shafts and disks leads to an open channel at the engine centerline. This has immense potential for reduced jet noise and for the accomodation of an alternative form of thruster for use in a combined cycle. The use of ceramic composite materials has the potential for significantly reduced weight as well as higher working temperatures without cooling air. The exoskeletal configuration is also a natural stepping-stone to complete counter-rotating turbomachinery. Ultimately this will lead to reductions in weight, length, parts count and improved efficiency. The feasibility studies are in three parts. Part I-Systems and Component Requirements addressed the mechanical aspects of components from a functionality perspective. This effort laid the groundwork for preliminary design studies. Although important, it is not felt to be particularly original, and has therefore not been included in the current overview. Part 2-Preliminary Design Studies turned to some of the cycle and performance issues inherent in an exoskeletal configuration and some initial attempts at preliminary design of turbomachinery were described. Twin-spoon and single-spool 25.800-lbf-thrust turbofans were used as reference vehicles in a mid-size commercial subsonic category in addition to a single-spool 5,000-lbf-thrust turbofan that represented a general aviation application. The exoskeletal engine, with its open centerline, has tremendous potential for noise suppression and some preliminary analysis was done which began to quantify the benefits. Part 3-Additional Preliminary Design Studies revisited the design of single-spool 25,800-lbf-thrust turbofan configurations, but in addition to the original FPR = 1.6 and BPR = 5.1 reference engine, two additional configurations used FPR = 2.4 and BPR = 3.0 and FPR = 3.2 and BPR

  7. Thrust calculation of electric solar wind sail by particle-in-cell simulation

    NASA Astrophysics Data System (ADS)

    Hoshi, Kento; Kojima, Hirotsugu; Muranaka, Takanobu; Yamakawa, Hiroshi

    2016-09-01

    In this study, thrust characteristics of an electric solar wind sail were numerically evaluated using full three-dimensional particle-in-cell (PIC) simulation. The thrust obtained from the PIC simulation was lower than the thrust estimations obtained in previous studies. The PIC simulation indicated that ambient electrons strongly shield the electrostatic potential of the tether of the sail, and the strong shield effect causes a greater thrust reduction than has been obtained in previous studies. Additionally, previous expressions of the thrust estimation were modified by using the shielded potential structure derived from the present simulation results. The modified thrust estimation agreed very well with the thrust obtained from the PIC simulation.

  8. Optimum Low Thrust Elliptic Orbit Transfer Using Numerical Averaging

    NASA Astrophysics Data System (ADS)

    Tarzi, Zahi Bassem

    Low-thrust electric propulsion is increasingly being used for spacecraft missions primarily due to its high propellant efficiency. Since analytical solutions for general low-thrust transfers are not available, a simple and fast method for low-thrust trajectory optimization is of great value for preliminary mission planning. However, few low-thrust trajectory tools are appropriate for preliminary mission design studies. The method presented in this paper provides quick and accurate solutions for a wide range of transfers by using numerical orbital averaging to improve solution convergence and include orbital perturbations. Thus allowing preliminary trajectories to be obtained for transfers which involve many revolutions about the primary body. This method considers minimum fuel transfers using first order averaging to obtain the fuel optimum rates of change of the equinoctial orbital elements in terms of each other and the Lagrange multipliers. Constraints on thrust and power, as well as minimum periapsis, are implemented and the equations are averaged numerically using a Gaussian quadrature. The use of numerical averaging allows for more complex orbital perturbations to be added without great difficulty. Orbital perturbations due to solar radiation pressure, atmospheric drag, a non-spherical central body, and third body gravitational effects have been included. These perturbations have not been considered by previous methods using analytical averaging. Thrust limitations due to shadowing have also been considered in this study. To allow for faster convergence of a wider range of problems, the solution to a transfer which minimizes the square of the thrust magnitude is used as a preliminary guess for the minimum fuel problem. Thus, this method can be quickly applied to many different types of transfers which may include various perturbations. Results from this model are shown to provide a reduction in propellant mass required over previous minimum fuel solutions

  9. Channel-wing System for Thrust Deflection and Force/Moment Generation

    NASA Technical Reports Server (NTRS)

    Englar, Robert J. (Inventor); Bushnell, Dennis M. (Inventor)

    2006-01-01

    An aircraft comprising a Channel Wing having blown c h - ne1 circulation control wings (CCW) for various functions. The blown channel CCW includes a channel that has a rounded or near-round trailing edge. The channel further has a trailing-edge slot that is adjacent to the rounded trailing edge of the channel. The trailing-edge slot has an inlet connected to a source of pressurized air and is capable of tangentially discharging pressurized air over the rounded trailing edge. The aircraft further has a propeller that is located in the channel and ahead of the rounded trailing edge of the channel. The propeller provides a propeller thrust exhaust stream across the channel wing to propel the aircraft through the air and to provide high lift. The pressurized air being discharged over the rounded trailing edge provides a high lift that is obtained independent of an aircraft angle of attack, thus preventing the asymmetry. separated flow, and stall experienced by the CC wing at the high angle of attack it required for high lift generation. The aircraft can further include blown outboard circulation control wings (CCW) that are synergistically connected to the blown channel CCWs. The blown outboard CCWs provide additional high lift, control thrust/drag interchange, and can provide all three aerodynamic moments when differential blowing is applied front-to-rear or left-to-right. Both the blown channel CCW and the outboard CCW also have leading-edge blowing slots to prevent flow separation or to provide aerodynamic moments for control.

  10. Geologic mapping delineates new thrust sheets, duplex structures, and timing relationships between the Meade and Crawford thrusts in Wyoming, Idaho, and Utah

    SciTech Connect

    Coogan, J.C.

    1993-04-01

    New geologic maps of nine complete and six partial 7.5[prime] quadrangles delineate a large-scale duplex comprised of at least five thrust sheets that together form the Sheep Creek culmination in the footwall of the Meade thrust. From west to east, the Sheep Creek culmination includes the Home Canyon, Sheep Creek, Red Mountain, northern Crawford, and Afton thrust sheets. The thrusts are floored by the regional sole decollement in the Cambrian Gros Ventre Formation and merge upward with a roof thrust that lies along the Meade thrust in the west and decollements in the Jurassic Gypsum Spring and Preuss salt intervals in the east. The individual thrusts of Sheep Creek culmination are generally blind thrusts that are recognized by integrating the surface mapping with subsurface well and seismic data in balanced cross sections. The common map expression for individual thrust sheets is marked by translated fault-propagation anticlines in upper Paleozoic, Triassic, and lower Jurassic rocks that are bordered to the east by frontal decollement fold trains in middle and upper Jurassic rocks. The Meade thrust is folded above the Sheep Creek culmination in the northern part of the map area, and it is specifically folded above the Crawford fault-propagation fold, Sublette anticline, north of the map area at Elk Valley, Idaho. Thus, the Meade and Crawford thrusts are not coeval, linked thrusts as previously assumed. Instead, the individual thrusts of Sheep Creek culmination form a linked, eastward-younging thrust system along which 30 km of Crawford thrust displacement in Utah is partitioned between the Sheep Creek, Red Mountain, northern Crawford, and Afton thrusts in Idaho and Wyoming.

  11. Modelling hanging wall accommodation above rigid thrust ramps

    NASA Astrophysics Data System (ADS)

    Bonini, Marco; Sokoutis, Dimitrios; Mulugeta, Genene; Katrivanos, Emmanouil

    2000-08-01

    Experimental models are used to study the role of material rheology in hanging wall accommodation above rigid flat-ramp-flat thrust footwalls. The deformation in the hanging wall was accomplished by forwards sliding along a rigid basal staircase trajectory with a variable ramp angle, α, ranging from 15° to 60°. We model different ramp angles to examine hanging wall accommodation styles above thrust ramps of overthrust faults ( α ranging from 15° to 30°), as well as above pre-existing normal faults ( α ranging from 45° to 60°). For the hanging walls we used stratified frictional (sand) and viscous (silicone putty) materials. In this paper we study three types of models. Type 1 models represent purely frictional hanging walls where accommodation above thrust ramps was by layer-parallel thickening and by generating a series of back thrusts. Type 2 and 3 models represent stratified frictional/viscous hanging walls. In these models, accommodation was by a complex association of reverse and normal faults, mainly controlled by the rheological anisotropy as well as by the ramp inclination angle α. In Type 2 models the silicone covered only the lower flat, while in Type 3 models it also covered the rigid ramp. For α≤30° in Type 2 models and α≤45° in Type 3 models, the viscous layer inhibited the development of back thrusts in the frictional hanging wall, instead the silicone thickened to develop a 'ductile ramp'. For α-values higher than 30° in Type 2 models and α=45° in Type 3 models, back thrusts develop in response to the bulk compression. The experiments simulate many structures observed above natural thrust ramps with α≤30° and pre-existing normal faults with α≥45°. The models emphasise the importance of a basal ductile layer, which allows the hanging wall to step-up over the rigid ramp by building up its own ductile ramp. The models also emphasise that foreland-directed normal faulting can develop at a thrust front in the case that the

  12. Bilateral and multiple cavitation sounds during upper cervical thrust manipulation

    PubMed Central

    2013-01-01

    Background The popping produced during high-velocity, low-amplitude (HVLA) thrust manipulation is a common sound; however to our knowledge, no study has previously investigated the location of cavitation sounds during manipulation of the upper cervical spine. The primary purpose was to determine which side of the spine cavitates during C1-2 rotatory HVLA thrust manipulation. Secondary aims were to calculate the average number of pops, the duration of upper cervical thrust manipulation, and the duration of a single cavitation. Methods Nineteen asymptomatic participants received two upper cervical thrust manipulations targeting the right and left C1-2 articulation, respectively. Skin mounted microphones were secured bilaterally over the transverse process of C1, and sound wave signals were recorded. Identification of the side, duration, and number of popping sounds were determined by simultaneous analysis of spectrograms with audio feedback using custom software developed in Matlab. Results Bilateral popping sounds were detected in 34 (91.9%) of 37 manipulations while unilateral popping sounds were detected in just 3 (8.1%) manipulations; that is, cavitation was significantly (P < 0.001) more likely to occur bilaterally than unilaterally. Of the 132 total cavitations, 72 occurred ipsilateral and 60 occurred contralateral to the targeted C1-2 articulation. In other words, cavitation was no more likely to occur on the ipsilateral than the contralateral side (P = 0.294). The mean number of pops per C1-2 rotatory HVLA thrust manipulation was 3.57 (95% CI: 3.19, 3.94) and the mean number of pops per subject following both right and left C1-2 thrust manipulations was 6.95 (95% CI: 6.11, 7.79). The mean duration of a single audible pop was 5.66 ms (95% CI: 5.36, 5.96) and the mean duration of a single manipulation was 96.95 ms (95% CI: 57.20, 136.71). Conclusions Cavitation was significantly more likely to occur bilaterally than unilaterally during upper cervical HVLA

  13. Simple control laws for low-thrust orbit transfers

    NASA Technical Reports Server (NTRS)

    Petropoulos, Anastassios E.

    2003-01-01

    Two methods are presented by which to determine both a thrust direction and when to apply thrust to effect specified changes in any of the orbit elements except for true anomaly, which is assumed free. The central body is assumed to be a point mass, and the initial and final orbits are assumed closed. Thrust, when on, is of a constant value, and specific impulse is constant. The thrust profiles derived from the two methods are not propellant-optimal, but are based firstly on the optimal thrust directions and location on the osculating orbit for changing each of the orbit elements and secondly on the desired changes in the orbit elements. Two examples of transfers are presented, one in semimajor axis and inclination, and one in semimajor axis and eccentricity. The latter compares favourably with a propellant-optimized transfer between the same orbits. The control laws have few input parameters, but can still capture the complexity of a wide variety of orbit transfers.

  14. Grenville foreland thrust belt hidden beneath the eastern US midcontinent

    SciTech Connect

    Hauser, E.C. )

    1993-01-01

    Grenville foreland thrust structures are observed beneath the eastern US midcontinent on COCORP (Consortium for Continental Reflection Profiling) line OH-1 and a short seismic line in southwest Ohio. These structures represent the first evidence for a significant Grenville foreland thrust belt preserved in eastern North America. On the COCORP lines, the structures include a thrust ramp anticline and an associated asymmetric syncline. The Grenville front tectonic zone appears to truncate these foreland structures, indicating a later, second phase expressed as a deeply penetrating, out-of-sequence thrust zone associated with the main uplift of the Grenville province on the east. A short, shallow seismic line in southwestern Ohio reveals an east-dipping sequence of prominently layered rocks that may lie above a footwall ramp to a deeper Grenville thrust fault. A drill hole into the less reflective top of this dipping sequence encountered unmetamorphosed sedimentary rocks like those increasingly reported from other drill holes in southwestern Ohio and adjacent states. Although possibly part of a late Precambrian (Keweenawan ) rift, these clastic sedimentary rocks may instead preserve evidence of a heretofore unrecognized Grenville foreland basin in eastern North America. Alternatively these Precambrian sedimentary rocks together with an underlying, but yet undrilled, strongly layered sequence may correlate with similarly layered rocks observed on COCORP and industrial seismic lines within the Middle Proterozoic granite-rhyolite province to the west in Indiana and Illinois and indicate that unmetamorphosed sedimentary material is an important constituent of the granite-rhyolite province. 25 refs., 6 figs.

  15. Thrust Augmentation Measurements Using a Pulse Detonation Engine Ejector

    NASA Technical Reports Server (NTRS)

    Santoro, Robert J.; Pal, Sibtosh

    2005-01-01

    Results of an experimental effort on pulse detonation driven ejectors are presented and discussed. The experiments were conducted using a pulse detonation engine (PDE)/ejector setup that was specifically designed for the study and operated at frequencies up to 50 Hz. The results of various experiments designed to probe different aspects of the PDE/ejector setup are reported. The baseline PDE was operated using ethylene (C2H4) as the fuel and an oxygen/nitrogen O2 + N2) mixture at an equivalence ratio of one. The PDE only experiments included propellant mixture characterization using a laser absorption technique, high fidelity thrust measurements using an integrated spring-damper system, and shadowgraph imaging of the detonation/shock wave structure emanating from the tube. The baseline PDE thrust measurement results at each desired frequency agree with experimental and modeling results reported in the literature. These PDE setup results were then used as a basis for quantifying thrust augmentation for various PDE/ejector setups with constant diameter ejector tubes and various ejector lengths, the radius of curvature for the ejector inlets and various detonation tube/ejector tube overlap distances. For the studied experimental matrix, the results showed a maximum thrust augmentation of 106% at an operational frequency of 30 Hz. The thrust augmentation results are complemented by shadowgraph imaging of the flowfield in the ejector tube inlet area and high frequency pressure transducer measurements along the length of the ejector tube.

  16. Thrust Augmentation Measurements for a Pulse Detonation Engine Driven Ejector

    NASA Technical Reports Server (NTRS)

    Pal, S.; Santoro, Robert J.; Shehadeh, R.; Saretto, S.; Lee, S.-Y.

    2005-01-01

    Thrust augmentation results of an ongoing study of pulse detonation engine driven ejectors are presented and discussed. The experiments were conducted using a pulse detonation engine (PDE) setup with various ejector configurations. The PDE used in these experiments utilizes ethylene (C2H4) as the fuel, and an equi-molar mixture of oxygen and nitrogen as the oxidizer at an equivalence ratio of one. High fidelity thrust measurements were made using an integrated spring damper system. The baseline thrust of the PDE engine was first measured and agrees with experimental and modeling results found in the literature. Thrust augmentation measurements were then made for constant diameter ejectors. The parameter space for the study included ejector length, PDE tube exit to ejector tube inlet overlap distance, and straight versus rounded ejector inlets. The relationship between the thrust augmentation results and various physical phenomena is described. To further understand the flow dynamics, shadow graph images of the exiting shock wave front from the PDE were also made. For the studied parameter space, the results showed a maximum augmentation of 40%. Further increase in augmentation is possible if the geometry of the ejector is tailored, a topic currently studied by numerous groups in the field.

  17. Orbit adjust maneuvers using very small tangential thrust

    NASA Astrophysics Data System (ADS)

    Anthony, Maurice L.

    1987-10-01

    This paper develops approximate analytical solutions of the problem of transfer between coplanar circular orbits using very small tangential thrust, where the thrust acceleration is constant. Preliminary studies are made of the motions of both ascending and descending vehicles under continuous thrust, using the two variable expansion method. It is recognized that a descent trajectory starting from circular conditions may be considered as an ascent trajectory that terminates with circular conditions, by running the time in reverse. To solve the transfer problem, both the trajectory ascending from the smaller radius and the trajectory descending from the larger radius are required to end on the same Keplerian orbit. That is, the semimajor axis and eccentricity at the termination of the first burn must match those at the initiation of the second burn (termination of thrust on the descent arc). If thrust continues for more than a revolution, the two burn transfer has multiple solutions. Numerical examples of the analytical results compare remarkably well with results obtained by integrating the equations of motion numerically.

  18. Sandbox modeling of evolving thrust wedges with different preexisting topographic relief: Implications for the Longmen Shan thrust belt, eastern Tibet

    NASA Astrophysics Data System (ADS)

    Sun, Chuang; Jia, Dong; Yin, Hongwei; Chen, Zhuxin; Li, Zhigang; Shen, Li; Wei, Dongtao; Li, Yiquan; Yan, Bin; Wang, Maomao; Fang, Shaozhi; Cui, Jian

    2016-06-01

    To understand the effects of substantial topographic relief on deformation localization in the seismically active mountains, like the Longmen Shan thrust belt in the eastern Tibet, sandbox experiments were performed based on the framework of the critical taper theory. First, a reference experiment revealed that the critical taper angle was 12° for our experimental materials. Subsequently, different proto wedges (subcritical (6° in taper angle), critical (12°), and supercritical (20°)) were introduced to cover the range of natural topographic relief, and we used two setups: setup A considered only across-strike topographic relief, whereas setup B investigated along-strike segmentation of topography, consist of two adjacent proto wedges. In all experiments, thrust wedges grew by in-sequence accretion of thrust sheets. Setup A revealed an alternating mode of slip partitioning on the accreted thrusts, with large-displacement thrust and small-displacement thrust developing in turn. And contrasting wedge evolutions occurred according to whether the proto wedge was subcritical or critical-supercritical. In setup B, the differential deformation along the strike produced transverse structures such as tear fault and lateral ramp during frontal accretion. The observed tear fault and its associated thrust system resemble the seismogenic fault system of the 2008 Mw7.9 Wenchuan earthquake. Our experimental results could also explain first-order deformation features observed in the Longmen Shan. Consequently, we conclude that topographic features, including topographic relief across the range and along-strike segmentation of topography, contribute significantly to the kinematics and deformation localization in such active mountains.

  19. Viscoplastic analysis of an experimental cylindrical thrust chamber liner

    NASA Technical Reports Server (NTRS)

    Arya, Vinod K.; Arnold, Steven M.

    1992-01-01

    A viscoplastic stress-strain analysis of an experimental cylindrical thrust chamber is presented. A viscoelastic constitutive model incorporating a single internal state variable that represents kinematic hardening was employed to investigate whether such a viscoplastic model could predict the experimentally observed behavior of the thrust chamber. Two types of loading cycles were considered: a short cycle of 3.5-s duration that corresponded to the experiments, and an extended loading cycle of 485.1 s duration that is typical of the Space Shuttle Main Engine (SSME) operating cycle. The analysis qualitatively replicated the deformation behavior of the component as observed in experiments designed to simulate SSME operating conditions. The analysis also showed that the mode and location of failure in the component may depend on the loading cycle. The results indicate that using viscoplastic models for structural analysis can lead to a more realistic life assessment of thrust chambers.

  20. Full-scale thrust reverser testing in an altitude facility

    NASA Technical Reports Server (NTRS)

    Mehalic, Charles M.; Lottig, Roy A.

    1987-01-01

    A two-dimensional convergent-divergent exhaust nozzle designed and fabricated by Pratt and Whitney Aircraft was installed on a PW1128 turbofan engine and tested during thrust reverser operation in an altitude facility at NASA Lewis Research Center. A unique collection system was used to capture the thrust reverser exhaust gas and transport it to the primary exhaust collector. Tests were conducted at three flight conditions with varying amounts of thrust reverse at each condition. Some reverser exhaust gas spillage by the collection system was encountered but engine performance was unaffected at all flight conditions tested. Based on the results of this test program, the feasibility of altitude testing of advanced multifunction exhaust nozzle systems has been demonstrated.

  1. Full-scale thrust reverser testing in an altitude facility

    NASA Technical Reports Server (NTRS)

    Mehalic, Charles M.; Lottig, Roy A.

    1987-01-01

    A two-dimensional convergent-divergent exhaust nozzle designed and fabricated by Pratt and Whitney Aircraft was installed on a PW1128 turbofan engine and tested during thrust reverser operation in an altitude facility at NASA Lewis Research Center. A unique collection system was used to capture the thrust reverser exhaust gas and transport it to the primary exhaust collector. Tests were conducted at three flight conditions with varying amounts of thrust reverse at each condition. Some reverser exhaust gas spillage by the collection system was encountered but engine performance was unaffected at all flight conditions tested. Based on the results of this test program, the feasibility of altitude testing of advanced multi-function exhaust nozzle systems has been demonstrated.

  2. A Determinate Model of Thrust-Augmenting Ejectors

    NASA Astrophysics Data System (ADS)

    Whitley, N.; Krothapalli, A.; van Dommelen, L.

    1996-01-01

    A theoretical analysis of the compressible flow through a constant-area jet-engine ejector in which a primary jet mixes with ambient fluid from a uniform free stream is pursued. The problem is reduced to a determinate mathematical one by prescribing the ratios of stagnation properties between the primary and secondary flows. For some selections of properties and parameters more than one solution is possible and the meaning of these solutions is discussed by means of asymptotic expansions. Our results further show that while under stationary conditions the thrust-augmentation ratio assumes a value of 2 in the large area-ratio limit, for a free-stream Mach number greater than 0.6 very little thrust augmentation is left. Due to the assumptions made, the analysis provides idealized values for the thrust-augmentation ratio and the mass flux entrainment factor.

  3. Equivalence ratio and constriction effects on RBCC thrust augmentation

    NASA Astrophysics Data System (ADS)

    Koupriyanov, M.; Etele, J.

    2011-06-01

    A theoretical analysis of a variable area rocket based combined cycle engine with and without simultaneous mixing and combustion is presented. The flowfield is solved using a steady, quasi-one-dimensional, inviscid control volume formulation with combustion effects included via a generalized equilibrium calculation. Compression augmentation is shown to be sensitive to the equivalence ratio within the primary rocket chamber, where ejector section performance is greatest at both low and high equivalence ratios but near a minimum at stoichiometric conditions. The thrust generated by the RBCC engine compared to that generated by the same rocket in isolation can be increased by as much as 12% at constriction ratios of between 45% and 50%. Thrust augmentation is also shown to vary with equivalence ratio, where for a fixed geometry the maximum thrust is generated at equivalence ratios slightly below unity.

  4. Over-the-wing model thrust reverser noise tests

    NASA Technical Reports Server (NTRS)

    Goodykoontz, J.; Gutierrez, O.

    1977-01-01

    Static acoustic tests were conducted on a 1/12 scale model over-the-wing target type thrust reverser. The model configuration simulates a design that is applicable to the over-the-wing short-haul advanced technology engine. Aerodynamic screening tests of a variety of reverser designs identified configurations that satisfied a reverse thrust requirement of 35 percent of forward thrust at a nozzle pressure ratio of 1.29. The variations in the reverser configuration included, blocker door angle, blocker door lip angle and shape, and side skirt shape. Acoustic data are presented and compared for the various configurations. The model data scaled to a single full size engine show that peak free field perceived noise (PN) levels at a 152.4 meter sideline distance range from 98 to 104 PNdb.

  5. Viscoplastic analysis of an experimental cylindrical thrust chamber liner

    NASA Technical Reports Server (NTRS)

    Arya, Vinod K.; Arnold, Steven M.

    1991-01-01

    A viscoplastic stress-strain analysis of an experimental cylindrical thrust chamber is presented. A viscoelastic constitutive model incorporating a single internal state variable that represents kinematic hardening was employed to investigate whether such a viscoplastic model could predict the experimentally observed behavior of the thrust chamber. Two types of loading cycles were considered: a short cycle of 3.5 sec. duration that corresponded to the experiments, and an extended loading cycle of 485.1 sec. duration that is typical of the Space Shuttle Main Engine (SSME) operating cycle. The analysis qualitatively replicated the deformation behavior of the component as observed in experiments designed to simulate SSME operating conditions. The analysis also showed that the mode and location in the component may depend on the loading cycle. The results indicate that using viscoplastic models for structural analysis can lead to a more realistic life assessment of thrust chambers.

  6. Cyclic fatigue analysis of rocket thrust chambers. Volume 2: Attitude control thruster high cycle fatigue

    NASA Technical Reports Server (NTRS)

    Miller, R. W.

    1974-01-01

    A finite element stress analysis was performed for the film cooled throat section of an attitude control thruster. The anlaysis employed the RETSCP finite element computer program. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the thruster operating cycle. The configuration and operating conditions considered, correspond to a flightweight integrated thruster assembly which was thrust pulse tested. The computed strain range was used in conjuction with Haynes 188 Universal Slopes minimum life data to predict throat section fatigue life. The computed number of cycles to failure was greater than the number of pulses to which the thruster was experimentally subjected without failure.

  7. Stabilized chromium oxide film

    DOEpatents

    Garwin, Edward L.; Nyaiesh, Ali R.

    1988-01-01

    Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150.ANG. are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

  8. Stabilized chromium oxide film

    DOEpatents

    Nyaiesh, A.R.; Garwin, E.L.

    1986-08-04

    Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150A are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

  9. Methods for determining atypical gate valve thrust requirements

    SciTech Connect

    Steele, R. Jr.; Watkins, J.C.; DeWall, K.G.

    1995-04-01

    Evaluating the performance of rising stem, wedge type, gate valves used in nuclear power plant is not a problem when the valves can be design-basis tested and their operability margins determined diagnostically. The problem occurs when they cannot be tested because of plant system limitations or when they can be tested only at some less-than-design-basis condition. To evaluate the performance of these valves requires various analytical and/or extrapolation methods by which the design-basis stem thrust requirement can be determined. This has been typically accomplished with valve stem thrust models used to calculate the requirements or by extrapolating the results from a less-than-design-basis test. The stem thrust models used by the nuclear industry to determine the opening or closing stem thrust requirements for these gate valves have generally assumed that the highest load the valve experiences during closure (but before seating) is at flow isolation and during unwedging or before flow initiation in the opening direction. However, during full-scale valve testing conducted for the USNRC, several of the valves produced stem thrust histories that showed peak closing stem forces occurring before flow isolation in the closing direction and after flow initiation in the opening direction. All of the valves that exhibited this behavior in the closing direction also showed signs of internal damage. Initially, we dismissed the early peak in the closing stem thrust requirement as damage-induced and labeled it nonpredictable behavior. Opening responses were not a priority in our early research, so that phenomenon was set aside for later evaluation.

  10. Fabrication of liquid-rocket thrust chambers by electroforming

    NASA Technical Reports Server (NTRS)

    Duscha, R. A.; Kazaroff, J. M.

    1974-01-01

    Electroforming has proven to be an excellent fabrication method for building liquid rocket regeneratively cooled thrust chambers. NASA sponsored technology programs have investigated both common and advanced methods. Using common procedures, several cooled spool pieces and thrust chambers have been made and successfully tested. The designs were made possible through the versatility of the electroforming procedure, which is not limited to simple geometric shapes. An advanced method of electroforming was used to produce a wire-wrapped, composite, pressure-loaded electroformed structure, which greatly increased the strength of the structure while still retaining the advantages of electroforming.

  11. Problems of millipound thrust measurement. The "Hansen Suspension"

    SciTech Connect

    Carta, David G.

    2014-03-31

    Considered in detail are problems which led to the need and use of the 'Hansen Suspension'. Also discussed are problems which are likely to be encountered in any low level thrust measuring system. The methods of calibration and the accuracies involved are given careful attention. With all parameters optimized and calibration techniques perfected, the system was found capable of a resolution of 10 {mu} lbs. A comparison of thrust measurements made by the 'Hansen Suspension' with measurements of a less sophisticated device leads to some surprising results.

  12. Thrust involvement of metamorphic rocks, southwestern Brooks Range, Alaska

    SciTech Connect

    Till, A.B.; Schmidt, J.M.; Nelson, S.W. )

    1988-10-01

    Most models for the tectonic history of the western Brooks Range treat Proterozoic and lower Paleozoic metamorphic rocks exposed in the southern part of the range as passive structural basement vertically uplifted late in the Mesozoic orogenic episode. Mapping in the metamorphic rocks shows that they can de divided into two structurally and metamorphically distinct belts, both of which were folded and thrust during the orogeny. Recognition of these belts and the nature of the contact separating them is critical to construction of accurate tectonic models of the Brooks Range fold and thrust belt.

  13. Low-thrust chemical propulsion system pump technology

    NASA Technical Reports Server (NTRS)

    Sabiers, R. L.; Siebenhaar, A.

    1981-01-01

    Candidate pump and driver systems for low thrust cargo orbit transfer vehicle engines which deliver large space structures to geosynchronous equatorial orbit and beyond are evaluated. The pumps operate to 68 atmospheres (1000 psi) discharge pressure and flowrates suited to cryogenic engines using either LOX/methane or LOX/hydrogen propellants in thrust ranges from 445 to 8900 N (100 to 2000 lb F). Analysis of the various pumps and drivers indicate that the low specific speed requirement will make high fluid efficiencies difficult to achieve. As such, multiple stages are required. In addition, all pumps require inducer stages. The most attractive main pumps are the multistage centrifugal pumps.

  14. Thrusting, halotectonics, and sedimentation in the Spanish Pyrenees

    SciTech Connect

    Anastasio, D.J.

    1988-08-01

    The Spanish Pyrenees are a linked system of regional thrust sheets and intermontane basins which formed during the Tertiary collision of the European and Iberian plates. The structural evolution of the Pyrenees was controlled by Mesozoic extensional structures and evaporite-bearing strata which served as the regional decollement and produced widespread pre- to postthrusting halotectonic folds. Palinspastic restoration of Cretaceous strata from the Pyrenean realm delineates a large normal-faulted embayment in the northern Iberian margin. Thicker sediments within the bay, coupled with the southward emplacement of the Cotiella-Montsec thrust sheet, caused underlying evaporites to flow toward the basin margins, producing folds such as the Mediano anticline.

  15. Medium-frequency impulsive-thrust-activated liquid hydrogen reorientation with Geyser

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Shyu, K. L.

    1992-01-01

    Efficient technique are studied for accomplishing propellant resettling through the minimization of propellant usage through impulsive thrust. A comparison between the use of constant-thrust and impulsive-thrust accelerations for the activation of propellant resettlement shows that impulsive thrust is superior to constant thrust for liquid reorientation in a reduced-gravity environment. This study shows that when impulsive thrust with 0.1-1.0-, and 10-Hz frequencies for liquid-fill levels in the range between 30-80 percent is considered, the selection of 1.0-Hz-frequency impulsive thrust over the other frequency ranges of impulsive thrust is the optimum. Characteristics of the slosh waves excited during the course of 1.0-Hz-frequency impulsive-thrust liquid reorientation were also analyzed.

  16. Was Himalayan normal faulting triggered by initiation of the Ramgarh-Munsiari Thrust?

    USGS Publications Warehouse

    Robinson, Delores M.; Pearson, Ofori N.

    2013-01-01

    The Ramgarh–Munsiari thrust is a major orogen-scale fault that extends for more than 1,500 km along strike in the Himalayan fold-thrust belt. The fault can be traced along the Himalayan arc from Himachal Pradesh, India, in the west to eastern Bhutan. The fault is located within the Lesser Himalayan tectonostratigraphic zone, and it translated Paleoproterozoic Lesser Himalayan rocks more than 100 km toward the foreland. The Ramgarh–Munsiari thrust is always located in the proximal footwall of the Main Central thrust. Northern exposures (toward the hinterland) of the thrust sheet occur in the footwall of the Main Central thrust at the base of the high Himalaya, and southern exposures (toward the foreland) occur between the Main Boundary thrust and Greater Himalayan klippen. Although the metamorphic grade of rocks within the Ramgarh–Munsiari thrust sheet is not significantly different from that of Greater Himalayan rock in the hanging wall of the overlying Main Central thrust sheet, the tectonostratigraphic origin of the two different thrust sheets is markedly different. The Ramgarh–Munsiari thrust became active in early Miocene time and acted as the roof thrust for a duplex system within Lesser Himalayan rocks. The process of slip transfer from the Main Central thrust to the Ramgarh–Munsiari thrust in early Miocene time and subsequent development of the Lesser Himalayan duplex may have played a role in triggering normal faulting along the South Tibetan Detachment system.

  17. An experimental investigation of thrust vectoring two-dimensional convergent-divergent nozzles installed in a twin-engine fighter model at high angles of attack

    NASA Technical Reports Server (NTRS)

    Capone, Francis J.; Mason, Mary L.; Leavitt, Laurence D.

    1990-01-01

    An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine thrust vectoring capability of subscale 2-D convergent-divergent exhaust nozzles installed on a twin engine general research fighter model. Pitch thrust vectoring was accomplished by downward rotation of nozzle upper and lower flaps. The effects of nozzle sidewall cutback were studied for both unvectored and pitch vectored nozzles. A single cutback sidewall was employed for yaw thrust vectoring. This investigation was conducted at Mach numbers ranging from 0 to 1.20 and at angles of attack from -2 to 35 deg. High pressure air was used to simulate jet exhaust and provide values of nozzle pressure ratio up to 9.

  18. Aircraft ground test and subscale model results of axial thrust loss caused by thrust vectoring using turning vanes

    NASA Technical Reports Server (NTRS)

    Johnson, Steven A.

    1992-01-01

    The NASA-Dryden F/A-18 high alpha research vehicle was modified to incorporate three independently controlled turning vanes located aft of the primary nozzle of each engine to vector thrust for pitch and yaw control. Ground measured axial thrust losses were compared with the results from a 14.25 pct. cold jet model for single and dual vanes inserted up to 25 degs into the engine exhaust. Data are presented for nozzle pressure ratios of 2.0 and 3.0 and nozzle exit areas of 253 and 348 sq in. The results indicate that subscale nozzle test results properly predict trends but underpredict the full scale results by approx. 1 to 4.5 pct. in thrust loss.

  19. Implicit time-marching solution of the Navier-Stokes equations for thrust reversing and thrust vectoring nozzle flows

    NASA Technical Reports Server (NTRS)

    Imlay, S. T.

    1986-01-01

    An implicit finite volume method is investigated for the solution of the compressible Navier-Stokes equations for flows within thrust reversing and thrust vectoring nozzles. Thrust reversing nozzles typically have sharp corners, and the rapid expansion and large turning angles near these corners are shown to cause unacceptable time step restrictions when conventional approximate factorization methods are used. In this investigation these limitations are overcome by using second-order upwind differencing and line Gauss-Siedel relaxation. This method is implemented with a zonal mesh so that flows through complex nozzle geometries may be efficiently calculated. Results are presented for five nozzle configurations including two with time varying geometries. Three cases are compared with available experimental data and the results are generally acceptable.

  20. Thrust Augmentation of a Turbojet Engine at Simulated Flight Conditions by Introduction of a Water-Alcohol Mixture into the Compressor

    NASA Technical Reports Server (NTRS)

    Useller, James W.; Auble, Carmon M.; Harvey, Ray W., Sr.

    1952-01-01

    An investigation was conducted at simulated high-altitude flight conditions to evaluate the use of compressor evaporative cooling as a means of turbojet-engine thrust augmentation. Comparison of the performance of the engine with water-alcohol injection at the compressor inlet, at the sixth stage of the compressor, and at the sixth and ninth stages was made. From consideration of the thrust increases achieved, the interstage injection of the coolant was considered more desirable preferred over the combined sixth- and ninth-stage injection because of its relative simplicity. A maximum augmented net-thrust ratio of 1.106 and a maximum augmented jet-thrust ratio of 1.062 were obtained at an augmented liquid ratio of 2.98 and an engine-inlet temperature of 80 F. At lower inlet temperatures (-40 to 40 F), the maximum augmented net-thrust ratios ranged from 1.040 to 1.076 and the maximum augmented jet-thrust ratios ranged from 1.027 to 1.048, depending upon the inlet temperature. The relatively small increase in performance at the lower inlet-air temperatures can be partially attributed to the inadequate evaporation of the water-alcohol mixture, but the more significant limitation was believed to be caused by the negative influence of the liquid coolant on engine- component performance. In general, it is concluded that the effectiveness of the injection of a coolant into the compressor as a means of thrust augmentation is considerably influenced by the design characteristics of the components of the engine being used.

  1. Tectonothermal history of an exhumed thrust-sheet-top basin: An example from the south Pyrenean thrust belt

    NASA Astrophysics Data System (ADS)

    Labaume, Pierre; Meresse, Florian; Jolivet, Marc; Teixell, Antonio; Lahfid, Abdeltif

    2016-05-01

    This paper presents a new balanced structural cross section of the Jaca thrust-sheet-top basin of the southern Pyrenees combined with paleothermometry and apatite fission track (AFT) thermochronology data. The cross section, based on field data and interpretation of industrial seismic reflection profiles, allows refinement of previous interpretations of the south directed thrust system, involving the identification of new thrust faults, and of the kinematic relationships between basement and cover thrusts from the middle Eocene to the early Miocene. AFT analysis shows a southward decrease in the level of fission track resetting, from totally reset Paleozoic rocks and lower Eocene turbidites (indicative of heating to Tmax > ~120°C), to partially reset middle Eocene turbidites and no/very weak resetting in the upper Eocene-lower Oligocene molasse (Tmax < ~60°C). AFT results indicate a late Oligocene-early Miocene cooling event throughout the Axial Zone and Jaca Basin. Paleomaximum temperatures determined by vitrinite reflectance measurements and Raman spectroscopy of carbonaceous material reach up to ~240°C at the base of the turbidite succession. Inverse modeling of AFT and vitrinite reflectance data with the QTQt software for key samples show compatibility between vitrinite-derived Tmax and the AFT reset level for most of the samples. However, they also suggest that the highest temperatures determined in the lowermost turbidites correspond to a thermal anomaly rather than burial heating, possibly due to fluid circulation during thrust activity. From these results, we propose a new sequential restoration of the south Pyrenean thrust system propagation and related basin evolution.

  2. Comparison: Direct thrust nuclear engine, nuclear electric engine, and a chemical engine for future space missions

    SciTech Connect

    Ramsthaler, J.H.; Sulmeisters, T.K.

    1988-01-01

    The need for an advanced direct thrust nuclear rocket propulsion engine has been identified in Project Forecast 2, Air Force Systems Command report which looks into future Air Force needs. The Air Force Astronautical Laboratory (AFAL) has been assigned responsibility for developing the nuclear engine, and they in turn have requested support from teams of contractors who have the full capability to assist in the development of the nuclear engine. The Idaho National Engineering Laboratory (INEL) has formed a team of experts with Martin Marietta for mission analysis. Science Applications International (SAIC) for flight safety analysis, Westinghouse for the nuclear subsystem, and Rocketdyne for the engine system. INEL is the overall program manager and manager for test facility design, construction and operation. The INEL team has produced plans for both the engine system and the ground test facility. AFAL has funded the INEL team to perform mission analyses to evaluate the cost, performance and operational advantages for a nuclear rocket engine in performing Air Force Space Missions. For those studies, the Advanced Nuclear Rocket Engine (ANRE), a scaled down NERVA derivative, was used as the baseline nuclear engine to compare against chemical engines and nuclear electric engines for performance of orbital transfer and maneuvering missions. 3 tabs.

  3. One-step synthesis of large-scale graphene film doped with gold nanoparticles at liquid-air interface for electrochemistry and Raman detection applications.

    PubMed

    Zhang, Panpan; Huang, Ying; Lu, Xin; Zhang, Siyu; Li, Jingfeng; Wei, Gang; Su, Zhiqiang

    2014-07-29

    We demonstrated a facile one-step synthesis strategy for the preparation of a large-scale reduced graphene oxide multilayered film doped with gold nanoparticles (RGO/AuNP film) and applied this film as functional nanomaterials for electrochemistry and Raman detection applications. The related applications of the fabricated RGO/AuNP film in electrochemical nonenzymatic H2O2 biosensor, electrochemical oxygen reduction reaction (ORR), and surface-enhanced Raman scattering (SERS) detection were investigated. Electrochemical data indicate that the H2O2 biosensor fabricated by RGO/AuNP film shows a wide linear range, low limitation of detection, high selectivity, and long-term stability. In addition, it was proved that the created RGO/AuNP film also exhibits excellent ORR electrochemical catalysis performance. The created RGO/AuNP film, when serving as SERS biodetection platform, presents outstanding performances in detecting 4-aminothiophenol with an enhancement factor of approximately 5.6 × 10(5) as well as 2-thiouracil sensing with a low concentration to 1 μM. It is expected that this facile strategy for fabricating large-scale graphene film doped with metallic nanoparticles will spark inspirations in preparing functional nanomaterials and further extend their applications in drug delivery, wastewater purification, and bioenergy. PMID:25015184

  4. Optimization of very-low-thrust trajectories using evolutionary neurocontrol

    NASA Astrophysics Data System (ADS)

    Dachwald, Bernd

    2005-07-01

    Searching optimal interplanetary trajectories for low-thrust spacecraft is usually a difficult and time-consuming task that involves much experience and expert knowledge in astrodynamics and optimal control theory. This is because the convergence behavior of traditional local optimizers, which are based on numerical optimal control methods, depends on an adequate initial guess, which is often hard to find, especially for very-low-thrust trajectories that necessitate many revolutions around the sun. The obtained solutions are typically close to the initial guess that is rarely close to the (unknown) global optimum. Within this paper, trajectory optimization problems are attacked from the perspective of artificial intelligence and machine learning. Inspired by natural archetypes, a smart global method for low-thrust trajectory optimization is proposed that fuses artificial neural networks and evolutionary algorithms into so-called evolutionary neurocontrollers. This novel method runs without an initial guess and does not require the attendance of an expert in astrodynamics and optimal control theory. This paper details how evolutionary neurocontrol works and how it could be implemented. The performance of the method is assessed for three different interplanetary missions with a thrust to mass ratio <0.15mN/kg (solar sail and nuclear electric).

  5. Engineering Research, Development and Technology, FY95: Thrust area report

    SciTech Connect

    1996-02-01

    The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the knowledge base, process technologies, specialized equipment, tools and facilities to support current and future LLNL programs. Engineering`s efforts are guided by a strategy that results in dual benefit: first, in support of Department of Energy missions, such as national security through nuclear deterrence; and second, in enhancing the nation`s economic competitiveness through their collaboration with US industry in pursuit of the most cost-effective engineering solutions to LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) identify key technologies relevant to LLNL programs where they can establish unique competencies, and (2) conduct high-quality research and development to enhance their capabilities and establish themselves as the world leaders in these technologies. To focus Engineering`s efforts, technology thrust areas are identified and technical leaders are selected for each area. The thrust areas are comprised of integrated engineering activities, staffed by personnel from the nine electronics and mechanical engineering divisions, and from other LLNL organizations. This annual report, organized by thrust area, describes Engineering`s activities for fiscal year 1995. The report provides timely summaries of objectives methods, and key results from eight thrust areas: computational electronics and electromagnetics; computational mechanics; microtechnology; manufacturing technology; materials science and engineering; power conversion technologies; nondestructive evaluation; and information engineering.

  6. Blueschist-facies metamorphism related to regional thrust faulting

    USGS Publications Warehouse

    Blake, M.C.; Irwin, W.P.; Coleman, R.G.

    1969-01-01

    Rocks of the blueschist (glaucophane schist) facies occur throughout the world in narrow tectonic belts associated with ultramafic rocks. In the Coast Range province of California, blueschist rocks are devloped in the eugeosynclinal Franciscan Formation of Late Mesozoic age. The blueschist rocks form a narrow belt for more than 800 km along the eastern margin of this province and commonly are separated from rocks of an overlying thrust plate by serpentinite. Increasing metamorphism upward toward the thrust fault is indicated mineralogically by a transition from pumpellyite to lawsonite and texturally by a transition from metagraywacke to schist. The blueschist metamorphism probably occurred during thrusting in a zone of anomalously high water pressure in the lower plate along the sole of the thrust fault. This tectonic mode of origin for blueschist differs from the generally accepted hypothesis involving extreme depth of burial. Other belts of blueschist-facies rocks, including the Sanbagawa belt of Japan, the marginal synclinal belt of New Zealand, and the blueschist-ultramafic belts of Venezuela, Kamchatka, Ural mountains, and New Caledonia have similar geologic relations and might be explained in the same manner. ?? 1969.

  7. Initial Thrust Measurements of Marshall's Ion-ioN Thruster

    NASA Technical Reports Server (NTRS)

    Schloeder, Natalie R.; Scogin, Tyler; Liu, Thomas M.; Walker, Mitchell L. R.; Polzin, Kurt A.; Dankanich, John W.; Aanesland, Ane

    2015-01-01

    Electronegative ion thrusters are a variation of tradition gridded ion thruster technology differentiated by the production and acceleration of both positive and negative ions. Benefits of electronegative ion thrusters include the elimination of lifetime-limiting cathodes from the thruster architecture and the ability to generate appreciable thrust from both charge species. Following the continued development of electronegative ion thruster technology as exhibited by the PEGASES (Plasma Propulsion with Electronegative GASES) thruster, direct thrust measurements are required to push interest in electronegative ion thruster technology forward. For this work, direct thrust measurements of the MINT (Marshall's Ion-ioN Thruster) will be taken on a hanging pendulum thrust stand for propellant mixtures of Sulfur Hexafluoride and Argon at volumetric flow rates of 5-25 sccm at radio frequency power levels of 100-600 watts at a radio frequency of 13.56 MHz. Acceleration grid operation is operated using a square waveform bias of +/-300 volts at a frequency of 25 kHz.

  8. Solid rocket booster thrust vector control subsystem description

    NASA Technical Reports Server (NTRS)

    Redmon, J., Jr. (Compiler)

    1983-01-01

    Major Solid Rocket Booster-Thrust Vector Control (SRB-TVC) subsystem components and subcomponents used in the Space Transportation System (STS) are identified. Simplified schematics, detailed schematics, figures, photographs, and data are included to acquaint the reader with the operation, performance, and physical layout as well as the materials and instrumentation used.

  9. Cooling of rocket thrust chambers with liquid oxygen

    NASA Technical Reports Server (NTRS)

    Armstrong, Elizabeth S.; Schlumberger, Julie A.

    1990-01-01

    Rocket engines using high pressure liquid oxygen (LOX) and kerosene (RP-1) as the propellants have been considered for future launch vehicle propulsion. Generaly, in regeneratively cooled engines, thefuel is used to cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability at high temperatures and pressures. Therefore, LOX is being considered as an alternative coolant. However, there has been concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot-gas side wall. To address this concern, an investigation was previously conducted with simulated fatigue cracks upstream of the thrust chamber throat. When these chambers were tested, an unexpected melting in the throat region developed which was not in line with the simulated fatigue cracks. The current experimental program was conducted in order to determine the cause for the failure in the earlier thrust chambers and to further investigate the effects of cracks in the thrust chamber liner upstream of the throat. The thrust chambers were tested at oxygen-to-fuel mixture ratios from 1.5 to 2.86 at a nominal chamber pressure of 8.6 MPa. As a result of the test series, the reason for the failure occurring in the earlier work was determined to be injector anomalies. The LOX leaking through the simulated fatigue cracks did not affect the integrity of the chambers.

  10. The Effect of Atmospheric Pressure on Rocket Thrust -- Part I.

    ERIC Educational Resources Information Center

    Leitner, Alfred

    1982-01-01

    The first of a two-part question asks: Does the total thrust of a rocket depend on the surrounding pressure? The answer to this question is provided, with accompanying diagrams of rockets. The second part of the question (and answer) are provided in v20 n7, p479, Oct 1982 of this journal. (Author/JN)

  11. Experiments on the Thrust of a Synthetic Jet in Crossflow

    NASA Astrophysics Data System (ADS)

    Ayers, Bradley; Henoch, Charles; Johari, Hamid

    2014-11-01

    A set of water tunnel experiments were conducted to investigate the effect of crossflow on the thrust of a synthetic jet. This research was motivated by the desire to generate significant turning moments on a fully-submerged, supercavitating vehicle without using control fins or canards. The water tunnel model was a sting-mounted, 3-inch diameter cylindrical body interfaced to a 6-axis waterproof load cell. The synthetic jet actuator was contained within the model and the jet orifice located near the aft end of the model was oriented perpendicular to the mean flow. The actuator consisted of an externally controlled solenoid driving a piston into the cavity. The jet thrust was measured over a broad range of synthetic jet operating parameters, including the actuation frequency and duty cycle, as well as the jet-to-crossflow velocity ratios. Previous work which is based on the slug flow model of an individual vortex ring predicts the time-averaged thrust scales with the square of actuation frequency and the stroke length. The measurements will be compared with the theoretical predictions, and the results will be used to assess the effect of crossflow on the thrust of synthetic jet. Sponsored by the ONR-ULI program.

  12. 14 CFR 33.79 - Fuel burning thrust augmentor.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel burning thrust augmentor. 33.79 Section 33.79 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.79 Fuel...

  13. 14 CFR 33.73 - Power or thrust response.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Power or thrust response. 33.73 Section 33.73 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.73 Power...

  14. Digital field trip to the Central Nevada Thrust Belt

    SciTech Connect

    Chamberlain, A.K.; Hook, S.C.; Frost, K.R.

    1996-12-31

    Hydrocarbon exploration in the Central Nevada Thrust Belt is still in its infancy. However, this thrust belt contains all the elements necessary for hydrocarbon accumulations: thick, organically-rich shales; reefs, regional unconformities, karst surfaces, porous sandstones, and extensive and pervasive fractures; anticlines tens of miles long by miles wide; thrust faults that juxtapose potential source and reservoir rocks; and oil seeps. Along a fairway from Las Vegas to Elko, for example, thick Mississippian shales contain 4-6% total organic carbon and are oil-prone and thermally mature. This presentation from a laptop computer and LCD projector is a multimedia version of our October 12-14, 1995 field trip to document the hydrocarbon potential of the thrust belt in Clark, Lincoln, and Nye Counties. Outcrop images were recorded by a digital camera that has a resolution equivalent to a 14 inch computer screen; these images were then downloaded to the computer. All of the images were processed digitally on location to enhance picture quality and color contrast. Many were annotated on location with our observations, measurements, and interpretations. These field annotations are supplemented in this presentation by laboratory analyses. The presentation includes full-color, annotated outcrop images, sounds, and animations. The results show the viability of the new, inexpensive digital cameras to geologic field work in which a multimedia report, ready for presentation to management, can be generated in the field.

  15. Operant Control of Pathological Tongue Thrust in Spastic Cerebral Palsy.

    ERIC Educational Resources Information Center

    Thompson, George A., Jr.

    1979-01-01

    The behavior modification procedure, carried out at mealtime with a ten-year-old retarded boy who had spastic cerebral palsy, consisted of differential reinforcement and punishment, and resulted in substantial decreases in tongue thrust (reverse swallowing) and food expulsion, and a large increase in observed chewing. (Author/DLS)

  16. A Regeneratively Cooled Thrust Chamber For The Fastrac Engine

    NASA Technical Reports Server (NTRS)

    Brown, Kendall K.; Sparks, Dave; Woodcock, Gordon

    2000-01-01

    Abstract This paper presents the development of a low-cost, regeneratively-cooled thrust chamber for the Fastrac engine. The chamber was fabricated using hydraformed copper tubing to form the coolant jacket and wrapped with a fiber reinforced polymer composite Material to form a structural jacket. The thrust chamber design and fabrication approach was based upon Space America. Inc.'s 12,000 lb regeneratively-cooled LOX/kerosene rocket engine. Fabrication of regeneratively cooled thrust chambers by tubewall construction dates back to the early US ballistic missile programs. The most significant innovations in this design was the development of a low-cost process for fabrication from copper tubing (nickel alloy was the usual practice) and use of graphite composite overwrap as the pressure containment, which yields an easily fabricated, lightweight pressure jacket around the copper tubes A regeneratively-cooled reusable thrust chamber can benefit the Fastrac engine program by allowing more efficient (cost and scheduler testing). A proof-of-concept test article has been fabricated and will he tested at Marshall Space Flight Center in the late Summer or Fall of 2000.

  17. 14 CFR 33.73 - Power or thrust response.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Power or thrust response. 33.73 Section 33.73 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.73 Power...

  18. 14 CFR 33.79 - Fuel burning thrust augmentor.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel burning thrust augmentor. 33.79 Section 33.79 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.79 Fuel...

  19. 14 CFR 33.73 - Power or thrust response.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Power or thrust response. 33.73 Section 33.73 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.73 Power...

  20. 14 CFR 33.79 - Fuel burning thrust augmentor.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel burning thrust augmentor. 33.79 Section 33.79 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.79 Fuel...

  1. 14 CFR 33.73 - Power or thrust response.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Power or thrust response. 33.73 Section 33.73 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.73 Power...

  2. Sub-micronewton thrust measurements of indium field emission thrusters

    NASA Technical Reports Server (NTRS)

    Ziemer, J. K.

    2003-01-01

    The performance of three indium field emission thrusters (In-FETs) developed by the Austrian Research Center Seibersdorf (ARCS) have been measured up to 200 muN, 2 mA, and 20 W using a submicronewton resolution thrust stand.

  3. Transient flow thrust prediction for an ejector propulsion concept

    NASA Technical Reports Server (NTRS)

    Drummond, Colin K.

    1989-01-01

    A method for predicting transient thrust augmenting ejector characteristics is introduced. The analysis blends classic self-similar turbulent jet descriptions with a mixing region control volume analysis to predict transient effects in a new way. Details of the theoretical foundation, the solution algorithm, and sample calculations are given.

  4. Design of an ion thruster movable grid thrust vectoring system

    NASA Astrophysics Data System (ADS)

    Kural, Aleksander; Leveque, Nicolas; Welch, Chris; Wolanski, Piotr

    2004-08-01

    Several reasons justify the development of an ion propulsion system thrust vectoring system. Spacecraft launched to date have used ion thrusters mounted on gimbals to control the thrust vector within a range of about ±5°. Such devices have large mass and dimensions, hence the need exists for a more compact system, preferably mounted within the thruster itself. Since the 1970s several thrust vectoring systems have been developed, with the translatable accelerator grid electrode being considered the most promising. Laboratory models of this system have already been built and successfully tested, but there is still room for improvement in their mechanical design. This work aims to investigate possibilities of refining the design of such movable grid thrust vectoring systems. Two grid suspension designs and three types of actuators were evaluated. The actuators examined were a micro electromechanical system, a NanoMuscle shape memory alloy actuator and a piezoelectric driver. Criteria used for choosing the best system included mechanical simplicity (use of the fewest mechanical parts), accuracy, power consumption and behaviour in space conditions. Designs of systems using these actuators are proposed. In addition, a mission to Mercury using the system with piezoelectric drivers has been modelled and its performance presented.

  5. Closed form low-thrust trajectories for Mars missions

    SciTech Connect

    Purvis, J.W.

    1992-01-01

    Several closed form trajectory solutions have been developed for low-thrust interplanetary flight and used with patched conics for analysis of combined propulsion systems. The solutions provide insight into alternative types of Mars missions, and show considerable mass savings for fast crewed missions with outbound trip times on the order of 90--100 days. 7 refs.

  6. Closed form low-thrust trajectories for Mars missions

    SciTech Connect

    Purvis, J.W.

    1992-08-01

    Several closed form trajectory solutions have been developed for low-thrust interplanetary flight and used with patched conics for analysis of combined propulsion systems. The solutions provide insight into alternative types of Mars missions, and show considerable mass savings for fast crewed missions with outbound trip times on the order of 90--100 days. 7 refs.

  7. Cooling of rocket thrust chambers with liquid oxygen

    NASA Technical Reports Server (NTRS)

    Armstrong, Elizabeth S.; Schlumberger, Julie A.

    1990-01-01

    Rocket engines using high pressure liquid oxygen (LOX) and kerosene (RP-1) as the propellants have been considered for future launch vehicle propulsion. Generally, in regeneratively cooled engines, the fuel is used to cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability at high temperatures and pressures. Therefore, LOX is being considered as an alternative coolant. However, there has been concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot-gas side wall. To address this concern, an investigation was previously conducted with simulated fatigue cracks upstream of the thrust chamber throat. When these chambers were tested, an unexpected melting in the throat region developed which was not in line with the simulated fatigue cracks. The current experimental program was conducted in order to determine the cause for the failure in the earlier thrust chambers and to further investigate the effects of cracks in the thrust chamber liner upstream of the throat. The thrust chambers were tested at oxygen-to-fuel mixture ratios from 1.5 to 2.86 at a nominal chamber pressure of 8.6 MPa. As a result of the test series, the reason for the failure occurring in the earlier work was determined to be injector anomalies. The LOX leaking through the simulated fatigue cracks did not affect the integrity of the chambers.

  8. REAR DETAIL OF RIGHT ENGINE AND WING. THRUST REVERSER REMAINS ...

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

    REAR DETAIL OF RIGHT ENGINE AND WING. THRUST REVERSER REMAINS OPEN. MECHANICS JONI BAINE (R) AND BILL THEODORE(L) OPEN FLAP CARRIAGE ACCESS WITH AN IMPACT GUN. THEY WILL CHECK TRANSMISSION FLUID AND OIL THE JACK SCREW. AT FAR LEFT UTILITY MECHANICS BEGIN BODY POLISHING. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

  9. Efficient Optimization of Low-Thrust Spacecraft Trajectories

    NASA Technical Reports Server (NTRS)

    Lee, Seungwon; Fink, Wolfgang; Russell, Ryan; Terrile, Richard; Petropoulos, Anastassios; vonAllmen, Paul

    2007-01-01

    A paper describes a computationally efficient method of optimizing trajectories of spacecraft driven by propulsion systems that generate low thrusts and, hence, must be operated for long times. A common goal in trajectory-optimization problems is to find minimum-time, minimum-fuel, or Pareto-optimal trajectories (here, Pareto-optimality signifies that no other solutions are superior with respect to both flight time and fuel consumption). The present method utilizes genetic and simulated-annealing algorithms to search for globally Pareto-optimal solutions. These algorithms are implemented in parallel form to reduce computation time. These algorithms are coupled with either of two traditional trajectory- design approaches called "direct" and "indirect." In the direct approach, thrust control is discretized in either arc time or arc length, and the resulting discrete thrust vectors are optimized. The indirect approach involves the primer-vector theory (introduced in 1963), in which the thrust control problem is transformed into a co-state control problem and the initial values of the co-state vector are optimized. In application to two example orbit-transfer problems, this method was found to generate solutions comparable to those of other state-of-the-art trajectory-optimization methods while requiring much less computation time.

  10. Separability of drag and thrust in undulatory animals and machines

    NASA Astrophysics Data System (ADS)

    Bale, Rahul; Shirgaonkar, Anup A.; Neveln, Izaak D.; Bhalla, Amneet Pal Singh; Maciver, Malcolm A.; Patankar, Neelesh A.

    2014-12-01

    For nearly a century, researchers have tried to understand the swimming of aquatic animals in terms of a balance between the forward thrust from swimming movements and drag on the body. Prior approaches have failed to provide a separation of these two forces for undulatory swimmers such as lamprey and eels, where most parts of the body are simultaneously generating drag and thrust. We nonetheless show that this separation is possible, and delineate its fundamental basis in undulatory swimmers. Our approach unifies a vast diversity of undulatory aquatic animals (anguilliform, sub-carangiform, gymnotiform, bal-istiform, rajiform) and provides design principles for highly agile bioinspired underwater vehicles. This approach has practical utility within biology as well as engineering. It is a predictive tool for use in understanding the role of the mechanics of movement in the evolutionary emergence of morphological features relating to locomotion. For example, we demonstrate that the drag-thrust separation framework helps to predict the observed height of the ribbon fin of electric knifefish, a diverse group of neotropical fish which are an important model system in sensory neurobiology. We also show how drag-thrust separation leads to models that can predict the swimming velocity of an organism or a robotic vehicle.

  11. Importance of combining convection with film cooling

    NASA Technical Reports Server (NTRS)

    Colladay, R. S.

    1971-01-01

    The interaction of film and convection cooling and its effect on wall cooling efficiency is investigated analytically for two cooling schemes for advanced gas turbine applications. The two schemes are full coverage- and counterflow-film cooling. In full coverage film cooling, the cooling air issues from a large number of small discrete holes in the surface. Counterflow film cooling is a film-convection scheme with film injection from a slot geometry. The results indicate that it is beneficial to utilize as much of the cooling air heat sink as possible for convection cooling prior to ejecting it as a film.

  12. Why style matters - uncertainty and structural interpretation in thrust belts.

    NASA Astrophysics Data System (ADS)

    Butler, Rob; Bond, Clare; Watkins, Hannah

    2016-04-01

    Structural complexity together with challenging seismic imaging make for significant uncertainty in developing geometric interpretations of fold and thrust belts. Here we examine these issues and develop more realistic approaches to building interpretations. At all scales, the best tests of the internal consistency of individual interpretations come from structural restoration (section balancing), provided allowance is made for heterogeneity in stratigraphy and strain. However, many existing balancing approaches give misleading perceptions of interpretational risk - both on the scale of individual fold-thrust (trap) structures and in regional cross-sections. At the trap-scale, idealised models are widely cited - fault-bend-fold, fault-propagation folding and trishear. These make entirely arbitrary choices for fault localisation and layer-by-layer deformation: precise relationships between faults and fold geometry are generally invalidated by real-world conditions of stratigraphic variation and distributed strain. Furthermore, subsurface predictions made using these idealisations for hydrocarbon exploration commonly fail the test of drilling. Rarely acknowledged, the geometric reliability of seismic images depends on the assigned seismic velocity model, which in turn relies on geological interpretation. Thus iterative approaches are required between geology and geophysics. The portfolio of commonly cited outcrop analogues is strongly biased to examples that simply conform to idealised models - apparently abnormal structures are rarely described - or even photographed! Insight can come from gravity-driven deep-water fold-belts where part of the spectrum of fold-thrust complexity is resolved through seismic imaging. This imagery shows deformation complexity in fold forelimbs and backlimbs. However, the applicability of these, weakly lithified systems to well-lithified successions (e.g. carbonates) of many foreland thrust belts remains conjectural. Examples of

  13. The Madong Early Paleozoic fold-thrust belt in southern Tarim Basin

    NASA Astrophysics Data System (ADS)

    Li, Yue-Jun; Wen, Lei; Li, Hui-Li; Peng, Geng-Xin; Qiu, Bin; Zheng, Duo-Ming; Luo, Jun-Cheng; Zhang, Qiang; Jia, Tie-Gan

    2016-01-01

    The Madong fold-thrust belt, which strikes NE-SW and thrusts southeastward, locates in the southern Tarim Basin. It is a part of the Kunlun Early Paleozoic foreland fold-thrust belt, and so is the Tangnan fold-thrust belt on the southeast of Madong. The Madong and Tangnan fold-thrust belts developed in Cambrian-Ordovician strata, and the Middle Cambrian gypsum-salt layer serves as the main décollement surface. The Middle Silurian and above strata unconformably overlie Madong while the upper Lower Silurian unconformably overlie Tangnan. On the basis of the facts that: (1) the Upper Ordovician is the youngest strata involved in the fold-thrust deformation, (2) the upper-Lower to Middle Silurian is the oldest strata unconformably overlying the foreland fold-thrust belt (including Madong and Tangnan), and growth strata exist in the upper part of the Upper Ordovician, we infer that the deformation time of the Kunlun Early Paleozoic foreland fold-thrust belt (including Madong and Tangnan) was during the Late Ordovician-Early Silurian. Tangnan is the residual of the major part of the foreland fold-thrust belt. Its northwestward thrust direction represents the main thrust direction of the foreland fold-thrust belt. Madong is the front belt of the foreland fold-thrust belt. It mainly thrusts southeastward and serves as the back-thrust belt of the Kunlun Early Paleozoic foreland fold-thrust belt. It is a triangle zone between Madong and Tangnan. The Madong fold-thrust belt is the best-preserved section of the Kunlun Early Paleozoic collisional orogenic belt, and thus is an important geological record of the Kunlun Early Paleozoic orogeny.

  14. Three-dimensional geometry, strain rates and basement deformation mechanisms of thrust-bend folding

    NASA Astrophysics Data System (ADS)

    Wibberley, Christopher A. J.

    1997-03-01

    Models for thrust-bend folding of an isotropic medium are used to predict initial basement thrust sheet geometries and sub-surface thrust fault shapes from final basement thrust sheet structure. Predicted strains and strain rates from these models are compared with data on deformation fabrics in an example of a basement thrustbend fold in order to characterise the deformation response to thrust-bend folding. The Glencoul thrust sheet in the Moine Thrust Zone of north-west Scotland is restored to an initial thrust sheet geometry. Spatial and orientation distribution data of syn-emplacement fractures and cataclastic fault zones from within the Glencoul thrust sheet are then compared with the strain and strain rate histories predicted by thrust-bend folding models. A different set of cataclastic fault seams is demonstrated to have been generated at each frontal thrust bend. Cataclastic failure is restricted to portions of the thrust sheet that have moved over frontal bends with smaller radii of curvature. From model thrust-bend geometries and an assumed slip rate of 1 x 10 -10 ms -1, estimated minimum (critical) strain rates required for fracture failure of the Lewisian basement are 10 -11 to 10 -14 s -1 for shear strain rates and 10 -12 to 10 -15 s -1 for extensional strain rates.

  15. Thrust Area Report, Engineering Research, Development and Technology

    SciTech Connect

    Langland, R. T.

    1997-02-01

    The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the knowledge base, process technologies, specialized equipment, tools and facilities to support current and future LLNL programs. Engineering`s efforts are guided by a strategy that results in dual benefit: first, in support of Department of Energy missions, such as national security through nuclear deterrence; and second, in enhancing the nation`s economic competitiveness through our collaboration with U.S. industry in pursuit of the most cost- effective engineering solutions to LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) identify key technologies relevant to LLNL programs where we can establish unique competencies, and (2) conduct high-quality research and development to enhance our capabilities and establish ourselves as the world leaders in these technologies. To focus Engineering`s efforts technology {ital thrust areas} are identified and technical leaders are selected for each area. The thrust areas are comprised of integrated engineering activities, staffed by personnel from the nine electronics and mechanical engineering divisions, and from other LLNL organizations. This annual report, organized by thrust area, describes Engineering`s activities for fiscal year 1996. The report provides timely summaries of objectives, methods, and key results from eight thrust areas: Computational Electronics and Electromagnetics; Computational Mechanics; Microtechnology; Manufacturing Technology; Materials Science and Engineering; Power Conversion Technologies; Nondestructive Evaluation; and Information Engineering. Readers desiring more information are encouraged to contact the individual thrust area leaders or authors. 198 refs., 206 figs., 16 tabs.

  16. Air stripping industrial wastewater

    SciTech Connect

    Lamarre, B.; Shearouse, D.

    1994-09-01

    Industrial wastewater can be quickly, efficiently and economically treated using air strippers. Air stripping removes a range of volatile and semi-volatile contaminants from water. And the performance of various types and sizes of tray-type air stripper for treating contaminated water now is highly predictable because of laboratory studies. Air stripping can be a fast, efficient and economical approach to treating industrial wastewater. However, since every industrial wastewater stream is unique, each must be evaluated to determine its constituents, its potentially adverse effects on treatability, and any pretreatment steps necessary to ensure desired results. The general principles of air stripping are simple. In an air stripper, the surfaces area of a film of contaminated water is maximized while air is directed across it. Contaminants at the air/water interface volatilize and are discharged to the atmosphere or to an off-gas treatment system.

  17. Extended performance solar electric propulsion thrust system study. Volume 3: Tradeoff studies of alternate thrust system configurations

    NASA Technical Reports Server (NTRS)

    Hawthorne, E. I.

    1977-01-01

    Several thrust system design concepts were evaluated and compared using the specifications of the most advanced 30 cm engineering model thruster as the technology base. Emphasis was placed on relatively high power missions. The extensions in thruster performance required for the Halley's comet mission were defined and alternative thrust system concepts were designed in sufficient detail for comparing mass, efficiency, reliability, structure, and thermal characteristics. Confirmation testing and analysis of thruster and power-processing components were performed. A baseline design was selected from the alternatives considered, and the design analysis and documentation were refined. A program development plan was formulated that outlines the work structure considered necessary for developing, qualifying, and fabricating the flight hardware for the baseline thrust system within the time frame of a project to rendezvous with Halley's comet. An assessment was made of the costs and risks associated with a baseline thrust system as provided to the mission project under this plan. Critical procurements and interfaces were identified and defined.

  18. Design of a thrust stand for high power electric propulsion devices

    NASA Technical Reports Server (NTRS)

    Haag, Thomas W.

    1989-01-01

    A thrust stand for use with high power electric propulsion devices was designed and tested. The thrust stand was specifically tailored to the needs of a 100 to 250 kW magnetoplasmadynamic (MPD) thruster program currently in progress at the NASA Lewis Research Center. The thrust stand structure was built as an inverted pendulum arrangement, supported at the base by water-cooled electrical power flexures. Thrust stand tares due to thruster discharge current were demonstrated to be negligible. Tares due to an applied field magnet current, after considerable effort, were reduced to less than 3.0 percent of measured thrust. These tares, however, could be determined independently and subtracted from the indicated thrust measurement. A detailed description is given for the thrust stand design and operation with a 100 kW class MPD device. Other thrust stand tares due to vibration and thermal effects are discussed, along with issues of accuracy and repeatability.

  19. F-15B ACTIVE with thrust vectoring nozzles on test stand at sunrise

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This November 13, 1995, photograph of the F-15 Advanced Controls Technology for Integrated Vehicles (ACTIVE) at NASA's Dryden Flight Research Center, Edwards, California, shows the aircraft on a test stand at sunrise. Not shown in this photograph are the aircraft's two new Pratt & Whitney nozzles that can turn up to 20 degrees in any direction. These nozzles give the aircraft thrust control in the pitch (up and down) and yaw (left and right) directions. This will reduce drag and increase fuel economy or range as compared with conventional aerodynamic controls, which increase the retarding forces (drag) acting upon the aircraft. These tests could result in significant performance increases for military and commercial aircraft. The research program is the product of a collaborative effort by NASA, the Air Force's Wright Laboratory, Pratt & Whitney, and McDonnell Douglas Aerospace. The aircraft was originally built as an F-15B (Serial #71-0290).

  20. Interseismic Strain Accumulation Across Metropolitan Los Angeles: Puente Hills Thrust

    NASA Astrophysics Data System (ADS)

    Argus, D.; Liu, Z.; Heflin, M. B.; Moore, A. W.; Owen, S. E.; Lundgren, P.; Drake, V. G.; Rodriguez, I. I.

    2012-12-01

    Twelve years of observation of the Southern California Integrated GPS Network (SCIGN) are tightly constraining the distribution of shortening across metropolitan Los Angeles, providing information on strain accumulation across blind thrust faults. Synthetic Aperture Radar Interferometry (InSAR) and water well records are allowing the effects of water and oil management to be distinguished. The Mojave segment of the San Andreas fault is at a 25° angle to Pacific-North America plate motion. GPS shows that NNE-SSW shortening due to this big restraining bend is fastest not immediately south of the San Andreas fault across the San Gabriel mountains, but rather 50 km south of the fault in northern metropolitan Los Angeles. The GPS results we quote next are for a NNE profile through downtown Los Angeles. Just 2 mm/yr of shortening is being taken up across the San Gabriel mountains, 40 km wide (0.05 micro strain/yr); 4 mm/yr of shortening is being taken up between the Sierra Madre fault, at the southern front of the San Gabriel mountains, and South Central Los Angeles, also 40 km wide (0.10 micro strain/yr). We find shortening to be more evenly distributed across metropolitan Los Angeles than we found before [Argus et al. 2005], though within the 95% confidence limits. An elastic models of interseismic strain accumulation is fit to the GPS observations using the Back Slip model of Savage [1983]. Rheology differences between crystalline basement and sedimentary basin rocks are incorporated using the EDGRN/EDCMP algorithm of Wang et al. [2003]. We attempt to place the Back Slip model into the context of the Elastic Subducting Plate Model of Kanda and Simons [2010]. We find, along the NNE profile through downtown, that: (1) The deep Sierra Madre Thrust cannot be slipping faster than 2 mm/yr, and (2) The Puente Hills Thrust and nearby thrust faults (such as the upper Elysian Park Thrust) are slipping at 9 ±2 mm/yr beneath a locking depth of 12 ±5 km (95% confidence limits