WorldWideScience

Sample records for in-bore propellant media

  1. In-Bore Magnetic Field Management

    National Research Council Canada - National Science Library

    Zielinski, Alex

    1999-01-01

    The turbine/alternator T/A) in the M734A1 Multi-Option Fuze for Mortar (MOFM) was identified as a component whose performance was altered by exposure to the in-bore magnetic induction produced by the armature in an electromagnetic railgun...

  2. Microbes Eating Rocket Propellant Hypergols (MERPHs)

    Data.gov (United States)

    National Aeronautics and Space Administration — Microbes will be attempted on proprietary green propellants. Evaluation and selection of optimal microbial media will be determined. Alteration of microbial...

  3. Perancangan Propeler Self-Propelled Barge

    Directory of Open Access Journals (Sweden)

    Billy Teguh kurniawan

    2013-03-01

    Full Text Available Makalah ini menyampaikan suatu penelitian tentang perancangan propeler yang optimal beserta pemilihan daya mesin yang efisien pada self-propelled barge dengan memperhitungkan besarnya nilai tahanan dari barge tersebut. Dengan penambahan sistem propulsi, diharapkan barge dapat beroperasi dengan lebih efisien dibandingkan saat barge beroperasi menggunakan sistem towing atau ditarik tug boat. Perhitungan tahanan barge dilakukan menggunakan metode Holtrop dan Guldhammer-Harvald sehingga dapat diperhi-tungkan geometri dan jenis propeler yang optimal beserta daya mesin yang efisien untuk barge. Propeler yang dianalisis adalah propeler tipe B-Troost Series, sedangkan variasi yang dilakukan untuk perencanaan propeler pada kajian ini adalah variasi putaran propeler pada rentang antara 310-800 rpm, serta variasi jumlah daun pada rentang tiga, empat, lima, dan enam. Besarnya nilai tahanan self-propelled barge untuk metode Holtrop adalah 105.91 kilonewton, sedangkan hasil per-hitungan dari metode Guldhammer-Harvald didapatkan nilai sebesar 109.14 kilonewton. Tipe propeler yang dipilih setelah dilakukan uji kavitasi adalah tipe Troost Series B4-40, dengan diameter sebesar 2.1 m, efisiensi sebesar 0.421, pitch ratio se-besar 0.591, dengan putaran propeler 400 rpm. Daya mesin yg dibutuhkan barge pada kondisi maksimum (BHPMCR sebesar 1669.5 HP. Dengan mempertimbangkan daya tersebut, maka dipilih mesin jenis Caterpillar tipe Marine 3516B yang mem-punyai daya maksimum sebesar 1285 kilowatt atau 1722.5 horsepower dengan putaran mesin sebesar 1200 rpm

  4. Tip-modified Propellers

    DEFF Research Database (Denmark)

    Andersen, Poul

    1999-01-01

    The paper deals with tip-modified propellers and the methods which, over a period of two decades, have been applied to develop such propellers. The development is driven by the urge to increase the efficiency of propellers and can be seen as analogous to fitting end plates and winglets to aircraft...... propeller, have efficiency increases of a reasonable magnitude in both open-water and behind-ship conditions....

  5. Hull-Propeller Interaction and Its Effect on Propeller Cavitation

    DEFF Research Database (Denmark)

    Regener, Pelle Bo

    computational effort. The boundary element method for propeller analysis includes a partially nonlinear cavitation model, which is able to predict partial sheet cavitation and supercavitation. The cavitation behaviour of the conventional propeller and the Kappel propeller from the earlier simulations...

  6. Cavitation simulation on marine propellers

    DEFF Research Database (Denmark)

    Shin, Keun Woo

    Cavitation on marine propellers causes thrust breakdown, noise, vibration and erosion. The increasing demand for high-efficiency propellers makes it difficult to avoid the occurrence of cavitation. Currently, practical analysis of propeller cavitation depends on cavitation tunnel test, empirical...

  7. Mobile propeller dynamometer validation

    Science.gov (United States)

    Morris, Mason Wade

    With growing interest in UAVs and OSU's interest in propeller performance and manufacturing, evaluating UAV propeller and propulsion system performance has become essential. In attempts to evaluate these propellers a mobile propeller dynamometer has been designed, built, and tested. The mobile dyno has been designed to be cost effective through the ability to load it into the back of a test vehicle to create simulated forward flight characteristics. This allows much larger propellers to be dynamically tested without the use of large and expensive wind tunnels. While evaluating the accuracy of the dyno, several improvements had to be made to get accurate results. The decisions made to design and improve the mobile propeller dyno will be discussed along with attempts to validate the dyno by comparing its results against known sources. Another large part of assuring the accuracy of the mobile dyno is determining if the test vehicle will influence the flow going into the propellers being tested. The flow into the propeller needs to be as smooth and uniform as possible. This is determined by characterizing the boundary layer and accelerated flow over the vehicle. This evaluation was accomplished with extensive vehicle aerodynamic measurements with the use of full-scale tests using a pitot-rake and the actual test vehicle. Additional tests were conducted in Oklahoma State University's low speed wind tunnel with a 1/8-scale model using qualitative flow visualization with smoke. Continuing research on the mobile dyno will be discussed, along with other potential uses for the dyno.

  8. PARAMETER DESIGN PROPELLER KAPAL

    Directory of Open Access Journals (Sweden)

    Muhammad Ridwan

    2012-04-01

    Full Text Available   Designer propeller kapal harus mempertimbangkan berbagai parameter untuk menghasilkan bentuk, type dan ukuran propeller yang memiliki nilai  efektifitas dan effisiensi propulsi tinggi. Propulsi kapal merupakan faktor yang mendominasi  operasional kapal, karena pemakaian bahan bakar untuk operasional propulsi kapal merupakan 42% dari total cost operasional kapal dan merupakan added value yang akan diperoleh oleh perusahaan pelayaran. Pertimbangan parameter desain propeller argonomis dapat mendukung tujuan di atas sehingga dapat menurunkan pemakaian bahan bakar hingga 20 % saat kapal dioperaionalkan.

  9. Performance optimization of marine propellers

    Directory of Open Access Journals (Sweden)

    Chang-Sup Lee

    2010-12-01

    In this paper, a design method for increasing performance of the marine propellers including the WCT propeller is suggested. It is described to maximize the performance of the propeller by adjusting expanded areas of the propeller blade. Results show that efficiency can be increased up to over 2% through the suggested design method.

  10. Autonomous Propellant Loading Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The AES Autonomous Propellant Loading (APL) project consists of three activities. The first is to develop software that will automatically control loading of...

  11. Modeling Propellant Tank Dynamics

    Data.gov (United States)

    National Aeronautics and Space Administration — The main objective of my work will be to develop accurate models of self-pressurizing propellant tanks for use in designing hybrid rockets. The first key goal is to...

  12. Neutron activation for logging the distribution of gold in bore-hole cores

    International Nuclear Information System (INIS)

    Rahmanian, H.; Watterson, J.I.W.

    1992-01-01

    A new method for the non-destructive determination of gold in bore-hole cores has been developed using instrumental neutron activation analysis with a 252 Cf source. The procedure obtains the distribution and concentration of gold along the longitudinal axis of the core i.e. a log of the gold concentration. The accuracy of the method is comparable to fire assay at a level of 2 ppm and has a detection limit of 1 ppm under the conditions used. The assay of the gold is carried out by employing a novel variation of the conventional comparator method using gold wires as both standard and flux monitor. A method is described for logging gold in bore-hole cores using neutron activation with a 160 μg 252 Cf neutron source. The method has a limit of detection of about 1 ppm under the described conditions. (author)

  13. A geostatistical estimation of zinc grade in bore-core samples

    International Nuclear Information System (INIS)

    Starzec, A.

    1987-01-01

    Possibilities and preliminary results of geostatistical interpretation of the XRF determination of zinc in bore-core samples are considered. For the spherical model of the variogram the estimation variance of grade in a disk-shape sample (estimated from the grade on the circumference sample) is calculated. Variograms of zinc grade in core samples are presented and examples of the grade estimation are discussed. 4 refs., 7 figs., 1 tab. (author)

  14. Propeller TAP flap

    DEFF Research Database (Denmark)

    Thomsen, Jørn Bo; Bille, Camilla; Wamberg, Peter

    2013-01-01

    The aim of this study was to examine if a propeller thoracodorsal artery perforator (TAP) flap can be used for breast reconstruction. Fifteen women were reconstructed using a propeller TAP flap, an implant, and an ADM. Preoperative colour Doppler ultrasonography was used for patient selection...... to identify the dominant perforator in all cases. A total of 16 TAP flaps were performed; 12 flaps were based on one perforator and four were based on two. A permanent silicone implant was used in 14 cases and an expander implant in two. Minor complications were registered in three patients. Two cases had...... major complications needing additional surgery. One flap was lost due to a vascular problem. Breast reconstruction can be performed by a propeller TAP flap without cutting the descending branch of the thoracodorsal vessels. However, the authors would recommend that a small cuff of muscle is left around...

  15. Disposal of Liquid Propellants

    Science.gov (United States)

    1990-03-13

    SYNTHESIS OF LIQUID PROPELLANT Hydroxylammonium nitrate (HAN), prepared via the electrolysis of nitric acid, is commercially available as a high-purity...stack gases, and brine solution from the wet scrubber (82). 5 Applicability/Limitation Most types of solid, liquid, and gaseous organic wastes or

  16. Hydrodynamics of Ship Propellers

    DEFF Research Database (Denmark)

    Breslin, John P.; Andersen, Poul

    of an intermittently cavitating propeller in a wake and the pressures and forces it exerts on the shaft and on the ship hull is examined. A final chapter discusses the optimization of efficiency of compound propulsors. The authors have taken care to clearly describe physical concepts and mathematical steps. Appendices...

  17. Low toxicity rocket propellants

    NARCIS (Netherlands)

    Wink, J.

    2014-01-01

    Hydrazine (N2H4) and its hypergolic mate nitrogen tetroxide (N2O4) are used on virtually all spacecraft and on a large number of launch vehicles. In recent years however, there has been an effort in identifying and developing alternatives to replace hydrazine as a rocket propellant.

  18. Measurement of in-bore side loads and comparison to first maximum yaw

    Directory of Open Access Journals (Sweden)

    Donald E. Carlucci

    2016-04-01

    Full Text Available In-bore yaw of a projectile in a gun tube has been shown to result in range loss if the yaw is significant. An attempt was made to determine if relationships between in-bore yaw and projectile First Maximum Yaw (FMY were observable. Experiments were conducted in which pressure transducers were mounted near the muzzle of a 155 mm cannon in three sets of four. Each set formed a cruciform pattern to obtain a differential pressure across the projectile. These data were then integrated to form a picture of what the overall pressure distribution was along the side of the projectile. The pressure distribution was used to determine a magnitude and direction of the overturning moment acting on the projectile. This moment and its resulting angular acceleration were then compared to the actual first maximum yaw observed in the test. The degree of correlation was examined using various statistical techniques. Overall uncertainty in the projectile dynamics was between 20% and 40% of the mean values of FMY.

  19. Dynamic nuclear polarization for magnetic resonance imaging. An in-bore approach

    Energy Technology Data Exchange (ETDEWEB)

    Krummenacker, Jan G.

    2012-07-01

    In this thesis, the development of an in-bore liquid state DNP polarizer for MRI applications operating in flow through mode at a magnetic field strength of 1.5 T was described. After an introductory chapter 1 and a chapter 2 on the theoretical background, chapter 3 dealt chiefly with the challenge of performing liquid state DNP at a high magnetic field of 9.2 T. The feasibility of performing liquid state DNP at this field was demonstrated for various solvents, as well as for metabolites in solution. Chapter 4 then moved to the aim of this work, the application of liquid state DNP for MRI experiments. It introduced the rationale of our approach, the hardware that was developed and demonstrated its performance in a clinical MRI tomograph.

  20. Dynamic nuclear polarization for magnetic resonance imaging. An in-bore approach

    International Nuclear Information System (INIS)

    Krummenacker, Jan G.

    2012-01-01

    In this thesis, the development of an in-bore liquid state DNP polarizer for MRI applications operating in flow through mode at a magnetic field strength of 1.5 T was described. After an introductory chapter 1 and a chapter 2 on the theoretical background, chapter 3 dealt chiefly with the challenge of performing liquid state DNP at a high magnetic field of 9.2 T. The feasibility of performing liquid state DNP at this field was demonstrated for various solvents, as well as for metabolites in solution. Chapter 4 then moved to the aim of this work, the application of liquid state DNP for MRI experiments. It introduced the rationale of our approach, the hardware that was developed and demonstrated its performance in a clinical MRI tomograph.

  1. In-bore transrectal MRI-guided prostate biopsies: Are there risk factors for complications?

    Energy Technology Data Exchange (ETDEWEB)

    Meier-Schroers, Michael, E-mail: michael.meier@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Homsi, Rami, E-mail: rami.homsi@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Kukuk, Guido, E-mail: guido.kukuk@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Wolter, Karsten, E-mail: karsten.wolter@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Decker, Georges, E-mail: georges.decker@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Fischer, Stefan, E-mail: stefan.fischer@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Marx, Christian, E-mail: christian.marx@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Schmeel, Frederic Carsten, E-mail: carsten.schmeel@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Block, Wolfgang, E-mail: wolfgang.block@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Sprinkart, Alois Martin, E-mail: sprinkart@uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Traeber, Frank, E-mail: frank.traeber@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Schild, Hans Heinz, E-mail: hans.schild@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Willinek, Winfried, E-mail: w.willinek@bk-trier.de [Department of Radiology, Neuroradiology, Sonography and Nuclear Medicine, Hospital of the Barmherzige Brüder Trier, Nordallee 1, 54292 Trier (Germany)

    2016-12-15

    Purpose: To systematically analyze risk factors for complications of in-bore transrectal MRI-guided prostate biopsies (MRGB). Materials and methods: 90 patients, who were scheduled for MRGB were included for this study. Exclusion criteria were coagulation disorders, therapy with anticoagulant drugs, and acute infections of the urinary and the lower gastrointestinal tract. Directly after, one week and one year after the biopsy, we assessed biopsy related complications (e.g. hemorrhages or signs of prostatitis). Differences between patients with and without complications were analyzed regarding possible risk factors: age, prostate volume, number of taken samples, biopsy duration, biopsy of more than one lesion, diabetes, arterial hypertension, hemorrhoids, benign prostate hyperplasia, carcinoma or prostatitis (according to histopathological analysis), and lesion localization. Complications were classified according to the Clavien-Dindo classification. Results: We observed 15 grade I complications in 90 biopsies (16.7%) with slight hematuria in 9 cases (10%), minor vasovagal reactions in 4 cases (4.4%), and urinary retention and positioning-related facial dysesthesia in 1 case each (1.1%). One patient showed acute prostatitis requiring antibiotics as the only grade II complication (1.1%). There were no adverse events that occurred later than one week. Complications grade III or higher such as pelvic abscesses, urosepsis or severe hemorrhages were not seen. There were no significant associations between the assessed risk factors and biopsy-related complications. Conclusion: In-bore transrectal MRI-guided prostate biopsies can be considered safe procedures in the diagnosis of prostate cancer with very low complication rates. There seem to be no risk factors for complications.

  2. In-bore transrectal MRI-guided prostate biopsies: Are there risk factors for complications?

    International Nuclear Information System (INIS)

    Meier-Schroers, Michael; Homsi, Rami; Kukuk, Guido; Wolter, Karsten; Decker, Georges; Fischer, Stefan; Marx, Christian; Schmeel, Frederic Carsten; Block, Wolfgang; Sprinkart, Alois Martin; Traeber, Frank; Schild, Hans Heinz; Willinek, Winfried

    2016-01-01

    Purpose: To systematically analyze risk factors for complications of in-bore transrectal MRI-guided prostate biopsies (MRGB). Materials and methods: 90 patients, who were scheduled for MRGB were included for this study. Exclusion criteria were coagulation disorders, therapy with anticoagulant drugs, and acute infections of the urinary and the lower gastrointestinal tract. Directly after, one week and one year after the biopsy, we assessed biopsy related complications (e.g. hemorrhages or signs of prostatitis). Differences between patients with and without complications were analyzed regarding possible risk factors: age, prostate volume, number of taken samples, biopsy duration, biopsy of more than one lesion, diabetes, arterial hypertension, hemorrhoids, benign prostate hyperplasia, carcinoma or prostatitis (according to histopathological analysis), and lesion localization. Complications were classified according to the Clavien-Dindo classification. Results: We observed 15 grade I complications in 90 biopsies (16.7%) with slight hematuria in 9 cases (10%), minor vasovagal reactions in 4 cases (4.4%), and urinary retention and positioning-related facial dysesthesia in 1 case each (1.1%). One patient showed acute prostatitis requiring antibiotics as the only grade II complication (1.1%). There were no adverse events that occurred later than one week. Complications grade III or higher such as pelvic abscesses, urosepsis or severe hemorrhages were not seen. There were no significant associations between the assessed risk factors and biopsy-related complications. Conclusion: In-bore transrectal MRI-guided prostate biopsies can be considered safe procedures in the diagnosis of prostate cancer with very low complication rates. There seem to be no risk factors for complications.

  3. Propellant combustion at low pressures

    Energy Technology Data Exchange (ETDEWEB)

    Schoyer, H.F.R.; Korting, P.A.O.G.

    1986-03-01

    The combustion characteristics of a family of composite propellants have been investigated at low (i.e., subatmospheric) pressures and three different temperatures. Although a de Vieille-type burning rate law appeared to be applicable, the burning rate exponent and coefficient vary strongly with the initial temperatures. Indications are that this is primarily due to the presence of nitroguanidine and oxalate. Combustion efficiency proved to be poor. At low pressures, all propellants are susceptible to irregular burning: above 50 kPa oscillatory combustion was hardly observed. All propellants exhibit distinct preferred frequencies for oscillatory combustion. These frequencies, being much lower than the acoustic frequency of the test system, are associated with the combustion characteristics of the propellants. They depend strongly on the combustion pressure and the initial propellant temperature.

  4. Cryogenic Propellant Storage and Transfer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Cryogenic Propellant Storage and Transfer project will demonstrate the capability to safely and efficiently store, transfer and measure cryogenic propellants,...

  5. Complications, Recovery, and Early Functional Outcomes and Oncologic Control Following In-bore Focal Laser Ablation of Prostate Cancer

    NARCIS (Netherlands)

    Lepor, H.; Llukani, E.; Sperling, D.; Futterer, J.J.

    2015-01-01

    From April 2013 to July 2014, 25 consecutive men participated in a longitudinal outcomes study following in-bore magnetic resonance imaging (MRI)-guided focal laser ablation (FLA) of prostate cancer (PCa). Eligibility criteria were clinical stage T1c and T2a disease; prostate-specific antigen (PSA)

  6. Application of theory to propeller design

    Science.gov (United States)

    Cox, G. G.; Morgan, W. B.

    1974-01-01

    The various theories concerning propeller design are discussed. The use of digital computers to obtain specific blade shapes to meet appropriate flow conditions is emphasized. The development of lifting-line and lifting surface configurations is analyzed. Ship propulsive performance and basic propeller design considerations are investigated. The characteristics of supercavitating propellers are compared with those of subcavitating propellers.

  7. Cryogenic Propellant Storage and Transfer

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Flight Demonstration development has been canceled in favor of a ground test bed development for of passive/active cryogenic propellant storage, transfer, and...

  8. Aircraft Propeller Hub Repair

    Energy Technology Data Exchange (ETDEWEB)

    Muth, Thomas R [ORNL; Peter, William H [ORNL

    2015-02-13

    The team performed a literature review, conducted residual stress measurements, performed failure analysis, and demonstrated a solid state additive manufacturing repair technique on samples removed from a scrapped propeller hub. The team evaluated multiple options for hub repair that included existing metal buildup technologies that the Federal Aviation Administration (FAA) has already embraced, such as cold spray, high velocity oxy-fuel deposition (HVOF), and plasma spray. In addition the team helped Piedmont Propulsion Systems, LLC (PPS) evaluate three potential solutions that could be deployed at different stages in the life cycle of aluminum alloy hubs, in addition to the conventional spray coating method for repair. For new hubs, a machining practice to prevent fretting with the steel drive shaft was recommended. For hubs that were refurbished with some material remaining above the minimal material condition (MMC), a silver interface applied by an electromagnetic pulse additive manufacturing method was recommended. For hubs that were at or below the MMC, a solid state additive manufacturing technique using ultrasonic welding (UW) of thin layers of 7075 aluminum to the hub interface was recommended. A cladding demonstration using the UW technique achieved mechanical bonding of the layers showing promise as a viable repair method.

  9. Aspects of Propeller Developements for a Submarine

    DEFF Research Database (Denmark)

    Andersen, Poul; kappel, Jens Julius; Spangenberg, Eugen

    2009-01-01

    Design and development of propellers for submarines are in some ways different from propellers for surface vessels. The most important demand is low acoustic signature that has priority over propeller efficiency, and the submarine propeller must be optimized with respect to acoustics rather than...... efficiency. Moreover the operating conditions of a submarine propeller are quite different. These aspects are discussed as well as the weighing of the various propeller parameters against the design objectives. The noise generated by the propeller can be characterized as thrust noise due to the inhomogeneous...... wake field of the submarine, trailing-edge noise and noise caused by turbulence in the inflow. The items discussed are demonstrated in a case study where a propeller of the Kappel type was developed. Three stages of the development are presented, including a design of an 8-bladed propeller where...

  10. Experimental Performance of a Novel Trochoidal Propeller

    Science.gov (United States)

    Roesler, Bernard; Epps, Brenden

    2015-11-01

    In the quest for energy efficiency in marine transportation, a promising marine propulsor concept is the trochoidal propeller. We have designed and tested a novel trochoidal propeller using a sinusoidal blade pitch function. The main results presented are measurements of thrust and torque, as well as the calculated efficiency, for a range of advance coefficients. The experimental data show narrow 95% confidence bounds, demonstrating high accuracy and repeatability in the experimental methods. We compare our sinusoidal-pitch trochoidal propeller with prior cross-flow propellers, as well as a representative screw propeller. While the efficiency of our propeller exceeds that of the cycloidal-pitch trochoidal propeller, it is slightly lower than the efficiencies of the other propellers considered. We also present a theoretical model that can be used to further explore and optimize such trochoidal propellers, leading to new avenues for improvements in marine propulsion systems.

  11. Marine propellers: the latest topics.

    Science.gov (United States)

    Kubo, H

    1996-02-01

    The impeller of the axial flow blood pump in an artificial heart is essentially based on the same principle as a marine propeller. Impellers designed for artificial hearts and marine propellers have a number of points in common. Decreased cavitation and relieved fluctuation load are only representative of them. As for a distinct concept of pressure distribution, the inverse method could be very useful. Skew may led to a more mild and natural character in the blood. Highly skewed blades and super elastic blades have the potential to decrease the burden on the entire circulatory system. This paper will address the main points and latest issues in propeller design concluding with a discussion of the implications of these issues for blood pump impellers.

  12. Thrust Deduction in Contrarotating Propellers

    Science.gov (United States)

    1974-11-01

    reduced by unbalancing the propelling thrust with smaller thrust carried on the forward propeller. UNCLASSIFIED SECURITY CLASIFICATION OF THIS...Webb lnst/Waird 1 154 W. Morgan 1 WHOI Ocean Engr 1 1644 R. Cumming 1 WPI Alden Hydr Lab 1 1552 J. McCarthy 1 SNAME 1 156 J. Hadler 1 Bethlehem Steel ...New York 30 5614 Report Distribution 1 Bethlehem Steel Sparrows 1 5641I Library 1 Bolt Beranek and Newman 1 5642 Library, Annapolis 1 Eastern Res Group 32

  13. Large Propellant Tank Cryo-Cooler (LPTC)

    Data.gov (United States)

    National Aeronautics and Space Administration — In rocket test and launch facilities, cryogenic propellants stored in tanks boils off due to heat leakage, with the following impacts:Ø   Waste, propellants boil off...

  14. Quadcopter thrust optimization with ducted-propeller

    Directory of Open Access Journals (Sweden)

    Kuantama Endrowednes

    2017-01-01

    Full Text Available In relation to quadcopter body frame model, propeller can be categorized into propeller with ducted and without ducted. This study present differences between those two using CFD (Computational Fluid Dynamics method. Both categories utilize two blade-propeller with diameter of 406 (mm. Propeller rotation generates acceleration per time unit on the volume of air. Based on the behavior of generated air velocity, ducted propeller can be modeled into three versions. The generated thrust and performance on each model were calculated to determine the best model. The use of ducted propeller increases the total weight of quadcopter and also total thrust. The influence of this modeling were analyzed in detail with variation of angular velocity propeller from 1000 (rpm to 9000 (rpm. Besides the distance between propeller tip and ducted barrier, the size of ducted is also an important part in thrust optimization and total weight minimization of quadcopter.

  15. Cryogenic Propellant Storage and Handling Efficiency Improvement

    Data.gov (United States)

    National Aeronautics and Space Administration — Stennis Space Center (SSC) is NASA’s top annual consumer of cryogenic propellants. Improvements in ground propellant system operations at SSC require having the...

  16. Mars Integrated Propellant Production System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Mars In-Situ Propellant Production System (IMISPPS) is an end-to-end system that will produce rocket propellant on Mars from CO2 in the Martian...

  17. Mars Integrated Propellant Production System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Mars In-Situ Propellant Production System (IMISPPS) is an end-to-end system that will produce rocket propellant on Mars from CO2 in the Martian...

  18. THE PROPELLER AND THE FROG

    International Nuclear Information System (INIS)

    Pan, Margaret; Chiang, Eugene

    2010-01-01

    'Propellers' in planetary rings are disturbances in ring material excited by moonlets that open only partial gaps. We describe a new type of co-orbital resonance that can explain the observed non-Keplerian motions of propellers. The resonance is between the moonlet underlying the propeller and co-orbiting ring particles downstream of the moonlet where the gap closes. The moonlet librates within the gap about an equilibrium point established by co-orbiting material and stabilized by the Coriolis force. In the limit of small libration amplitude, the libration period scales linearly with the gap azimuthal width and inversely as the square root of the co-orbital mass. The new resonance recalls but is distinct from conventional horseshoe and tadpole orbits; we call it the 'frog' resonance, after the relevant term in equine hoof anatomy. For a ring surface density and gap geometry appropriate for the propeller Bleriot in Saturn's A ring, our theory predicts a libration period of ∼4 years, similar to the ∼3.7 year period over which Bleriot's orbital longitude is observed to vary. These librations should be subtracted from the longitude data before any inferences about moonlet migration are made.

  19. Propelling arboriculture into the future

    Science.gov (United States)

    E. Gregory McPherson

    2011-01-01

    Research is the engine that propels arboriculture and urban forestry into the future. New knowledge, technologies, and tools provide arborists with improved tree care practices that result in healthier urban forests. The ISA Science and Research Committee (SRC) is composed of 13 professionals and researchers who are dedicated to elevating the importance of research...

  20. Explosive laser light initiation of propellants

    Science.gov (United States)

    Piltch, M.S.

    1993-05-18

    A improved initiator for artillery shell using an explosively generated laser light to uniformly initiate the propellent. A small quantity of a high explosive, when detonated, creates a high pressure and temperature, causing the surrounding noble gas to fluoresce. This fluorescence is directed into a lasing material, which lases, and directs laser light into a cavity in the propellant, uniformly initiating the propellant.

  1. Innovative boron nitride-doped propellants

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2016-04-01

    Full Text Available The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P. Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  2. Liquid Bismuth Propellant Flow Sensor

    Science.gov (United States)

    Polzin, Kurt A.; Stanojev, B. J.; Korman, V.

    2007-01-01

    Quantifying the propellant mass flow rate in liquid bismuth-fed electric propulsion systems has two challenging facets. First, the flow sensors must be capable of providing a resolvable measurement at propellant mass flow rates on the order of 10 mg/see with and uncertainty of less that 5%. The second challenge has to do with the fact that the materials from which the flow sensors are fabricated must be capable of resisting any of the corrosive effects associated with the high-temperature propellant. The measurement itself is necessary in order to properly assess the performance (thrust efficiency, Isp) of thruster systems in the laboratory environment. The hotspot sensor[I] has been designed to provide the bismuth propellant mass flow rate measurement. In the hotspot sensor, a pulse of thermal energy (derived from a current pulse and associated joule heating) is applied near the inlet of the sensor. The flow is "tagged" with a thermal feature that is convected downstream by the flowing liquid metal. Downstream, a temperature measurement is performed to detect a "ripple" in the local temperature associated with the passing "hotspot" in the propellant. By measuring the time between the upstream generation and downstream detection of the thermal feature, the flow speed can be calculated using a "time of flight" analysis. In addition, the system can be calibrated by measuring the accumulated mass exiting the system as a-function of time and correlating this with the time it takes the hotspot to convect through the sensor. The primary advantage of this technique is that it doesn't depend on an absolute measurement of temperature but, instead, relies on the observation of thermal features. This makes the technique insensitive to other externally generated thermal fluctuations. In this paper, we describe experiments performed using the hotspot flow sensor aimed at quantifying the resolution of the sensor technology. Propellant is expelled onto an electronic scale to

  3. Drag and Torque on Locked Screw Propeller

    Directory of Open Access Journals (Sweden)

    Tomasz Tabaczek

    2014-09-01

    Full Text Available Few data on drag and torque on locked propeller towed in water are available in literature. Those data refer to propellers of specific geometry (number of blades, blade area, pitch and skew of blades. The estimation of drag and torque of an arbitrary propeller considered in analysis of ship resistance or propulsion is laborious. The authors collected and reviewed test data available in the literature. Based on collected data there were developed the empirical formulae for estimation of hydrodynamic drag and torque acting on locked screw propeller. Supplementary CFD computations were carried out in order to prove the applicability of the formulae to modern moderately skewed screw propellers.

  4. Analysis of hydrological trend for radioactivity content in bore-hole water samples using wavelet based denoising

    International Nuclear Information System (INIS)

    Paul, Sabyasachi; Suman, V.; Sarkar, P.K.; Ranade, A.K.; Pulhani, V.; Dafauti, S.; Datta, D.

    2013-01-01

    A wavelet transform based denoising methodology has been applied to detect the presence of any discernable trend in 137 Cs and 90 Sr activity levels in bore-hole water samples collected four times a year over a period of eight years, from 2002 to 2009, in the vicinity of typical nuclear facilities inside the restricted access zones. The conventional non-parametric methods viz., Mann–Kendall and Spearman rho, along with linear regression when applied for detecting the linear trend in the time series data do not yield results conclusive for trend detection with a confidence of 95% for most of the samples. The stationary wavelet based hard thresholding data pruning method with Haar as the analyzing wavelet was applied to remove the noise present in the same data. Results indicate that confidence interval of the established trend has significantly improved after pre-processing to more than 98% compared to the conventional non-parametric methods when applied to direct measurements. -- Highlights: ► Environmental trend analysis with wavelet pre-processing was carried out. ► Removal of local fluctuations to obtain the trend in a time series with various mother wavelets. ► Theoretical validation of the methodology with model outputs. ► Efficient detection of trend for 137 Cs, 90 Sr in bore-hole water samples improves the associated confidence interval to more than 98%. ► Wavelet based pre-processing reduces the indecisive nature of the detected trend

  5. Self-propelled Leidenfrost droplets.

    Science.gov (United States)

    Linke, H; Alemán, B J; Melling, L D; Taormina, M J; Francis, M J; Dow-Hygelund, C C; Narayanan, V; Taylor, R P; Stout, A

    2006-04-21

    We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchetlike) topology. The pumping effect is observed when the liquid is in the Leidenfrost regime (the film-boiling regime), for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid.

  6. Explosive laser light initiation of propellants

    Energy Technology Data Exchange (ETDEWEB)

    Piltch, M.S.

    1992-12-31

    This invention is comprised of an improved initiator for artillery shell using an explosively generated laser light to uniformly initiate the propellent. A small quantity of a high explosive, when detonated, creates a high pressure and temperature, causing the surrounding noble gas to fluoresce. This fluorescence is directed into a lasing material, which lases, and directs laser light into a cavity in the propellant, uniformly initiating the propellant.

  7. High Seed Compressor for Propellant Densification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Propellant densification systems particularly for H2 require compression systems developing very large amounts of head. Development of this head requires multiple...

  8. Propeller Test Facilities Â

    Data.gov (United States)

    Federal Laboratory Consortium — Description: Three electrically driven whirl test stands are used to determine propeller (or other rotating device) performance at various rotational speeds. These...

  9. Nonsteady Combustion Mechanisms of Advanced Solid Propellants

    National Research Council Canada - National Science Library

    Branch, Melvyn

    1997-01-01

    .... The individual tasks which we are studying will pursue solid propellant decomposition under unsteady conditions, nonsteady aspects of gas phase flame structure measurements, numerical modeling...

  10. In-Bore Prostate Transperineal Interventions with an MRI-guided Parallel Manipulator: System Development and Preliminary Evaluation

    Science.gov (United States)

    Eslami, Sohrab; Shang, Weijian; Li, Gang; Patel, Nirav; Fischer, Gregory S.; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare M.; Iordachita, Iulian

    2015-01-01

    Background The robot-assisted minimally-invasive surgery is well recognized as a feasible solution for diagnosis and treatment of the prostate cancer in human. Methods In this paper the kinematics of a parallel 4 Degrees-of-Freedom (DOF) surgical manipulator designed for minimally invasive in-bore prostate percutaneous interventions through the patient's perineum. The proposed manipulator takes advantage of 4 sliders actuated by MRI-compatible piezoelectric motors and incremental rotary encoders. Errors, mostly originating from the design and manufacturing process, need to be identified and reduced before the robot is deployed in the clinical trials. Results The manipulator has undergone several experiments to evaluate the repeatability and accuracy of the needle placement which is an essential concern in percutaneous prostate interventions. Conclusion The acquired results endorse the sustainability, precision (about 1 mm in air (in x or y direction) at the needle's reference point) and reliability of the manipulator. PMID:26111458

  11. 75 FR 34390 - Airworthiness Directives; McCauley Propeller Systems Five-Blade Propeller Assemblies

    Science.gov (United States)

    2010-06-17

    ...-since-new (TSN). This proposed AD results from a report of a crack in a propeller hub. We are proposing... a propeller assembly removed from a Jetstream 41 airplane. The cracked hub has 7,807 hours TSN. The life limit of the hub is 18,000 hours TSN. The crack was found on the rear of the hub, on the propeller...

  12. High burn rate solid composite propellants

    Science.gov (United States)

    Manship, Timothy D.

    High burn rate propellants help maintain high levels of thrust without requiring complex, high surface area grain geometries. Utilizing high burn rate propellants allows for simplified grain geometries that not only make production of the grains easier, but the simplified grains tend to have better mechanical strength, which is important in missiles undergoing high-g accelerations. Additionally, high burn rate propellants allow for a higher volumetric loading which reduces the overall missile's size and weight. The purpose of this study is to present methods of achieving a high burn rate propellant and to develop a composite propellant formulation that burns at 1.5 inches per second at 1000 psia. In this study, several means of achieving a high burn rate propellant were presented. In addition, several candidate approaches were evaluated using the Kepner-Tregoe method with hydroxyl terminated polybutadiene (HTPB)-based propellants using burn rate modifiers and dicyclopentadiene (DCPD)-based propellants being selected for further evaluation. Propellants with varying levels of nano-aluminum, nano-iron oxide, FeBTA, and overall solids loading were produced using the HTPB binder and evaluated in order to determine the effect the various ingredients have on the burn rate and to find a formulation that provides the burn rate desired. Experiments were conducted to compare the burn rates of propellants using the binders HTPB and DCPD. The DCPD formulation matched that of the baseline HTPB mix. Finally, GAP-plasticized DCPD gumstock dogbones were attempted to be made for mechanical evaluation. Results from the study show that nano-additives have a substantial effect on propellant burn rate with nano-iron oxide having the largest influence. Of the formulations tested, the highest burn rate was a 84% solids loading mix using nano-aluminum nano-iron oxide, and ammonium perchlorate in a 3:1(20 micron: 200 micron) ratio which achieved a burn rate of 1.2 inches per second at 1000

  13. SSME propellant path leak detection

    Science.gov (United States)

    Crawford, Roger; Shohadaee, Ahmad Ali; Powers, W. T.

    1995-01-01

    The primary objective of this phase of the investigation is the experimental validation of techniques for detecting and analyzing propellant path external leaks which have a high probability of occurring on the SSME. The selection of candidate detection methods requires a good analytic model for leak plumes which would develop from external leaks and an understanding of radiation transfer through the leak plume. One advanced propellant path leak detection technique is obtained by using state-of-art technology of infrared (IR) thermal imaging systems combined with computer, digital image processing and expert systems for the engine protection. The feasibility of the IR leak plume detection will be evaluated on subscale simulated laboratory plumes to determine sensitivity, signal to noise, and general suitability for the application. The theoretical analysis was undertaken with the objective of developing and testing simple, easy-to-use models to predict the amount of radiation coming from a radiation source, background plate (BP), which can be absorbed, emitted and scattered by the gas leaks.

  14. KAPPEL Propeller. Development of a Marine Propeller with Non-planar Lifting Surfaces

    DEFF Research Database (Denmark)

    Kappel, J.; Andersen, Poul

    2002-01-01

    with higher efficiency and lower levels of noise and vibration excitation compared to conventional propellers designed for the same task. Conventional and KAPPEL propellers have been compared for a medium sized container ship and a product tanker. In total nine of these unconventional and two conventional...... propellers have been designed and models of all propellers have been examined with respect to cavitation and efficiency in the open water and behind conditions. Casting procedures, measurement procedures and stress analysis methods for the unconventional geometry of the KAPPEL propeller have been developed...

  15. Green plasticizers for multibase gun propellants (Lecture)

    NARCIS (Netherlands)

    Schoolderman, C.; Driel, C.A. van; Zebregs, M.

    2007-01-01

    TNO Defence, Security and Safety has a long history of research on gun propellants. Areas investigated are formulating (new ingredients, optimization), manufacturing, charge design and lifetime assessment [1,2,3,4,5]. In conventional propellants inert plasticizers are used to alter performance,

  16. Structure of Partially Premixed Flames and Advanced Solid Propellants

    National Research Council Canada - National Science Library

    Branch, Melvyn

    1998-01-01

    The combustion of solid rocket propellants of advanced energetic materials involves a complex process of decomposition and condensed phase reactions in the solid propellant, gaseous flame reactions...

  17. A Study of Flame Physics and Solid Propellant Rocket Physics

    National Research Council Canada - National Science Library

    Buckmaster, John

    2007-01-01

    ..., the combustion of heterogeneous propellants containing aluminum, the use of a genetic algorithm to optimally define false-kinetics parameters in propellant combustion modeling, the calculation of fluctuations...

  18. Propelling medical humanities in China.

    Science.gov (United States)

    Tang, Wei

    2017-05-23

    Advances in the study of the medical humanities and medical humanities education have been made over the past few decades. Many influential journals have published articles examining the role of medical humanities and medical humanities education, the development and evaluation of medical humanities, and the design of a curriculum for medical humanities education in Western countries. However, most articles related to medical humanities in China were published in Chinese, moreover, researchers have worked in relative isolation and published in disparate journals, so their work has not been systematically presented to and evaluated by international readers. The six companion articles featured in this issue describe the current status and challenge of medical humanities and medical humanities education in China in the hope of providing international readers with a novel and meaningful glimpse into medical humanities in China. This Journal is calling for greater publication of research on medical humanities and medical humanities education to propel medical humanities in China.

  19. Runtime and Pressurization Analyses of Propellant Tanks

    Science.gov (United States)

    Field, Robert E.; Ryan, Harry M.; Ahuja, Vineet; Hosangadi, Ashvin; Lee, Chung P.

    2007-01-01

    Multi-element unstructured CFD has been utilized at NASA SSC to carry out analyses of propellant tank systems in different modes of operation. The three regimes of interest at SSC include (a) tank chill down (b) tank pressurization and (c) runtime propellant draw-down and purge. While tank chill down is an important event that is best addressed with long time-scale heat transfer calculations, CFD can play a critical role in the tank pressurization and runtime modes of operation. In these situations, problems with contamination of the propellant by inclusion of the pressurant gas from the ullage causes a deterioration of the quality of the propellant delivered to the test article. CFD can be used to help quantify the mixing and propellant degradation. During tank pressurization under some circumstances, rapid mixing of relatively warm pressurant gas with cryogenic propellant can lead to rapid densification of the gas and loss of pressure in the tank. This phenomenon can cause serious problems during testing because of the resulting decrease in propellant flow rate. With proper physical models implemented, CFD can model the coupling between the propellant and pressurant including heat transfer and phase change effects and accurately capture the complex physics in the evolving flowfields. This holds the promise of allowing the specification of operational conditions and procedures that could minimize the undesirable mixing and heat transfer inherent in propellant tank operation. It should be noted that traditional CFD modeling is inadequate for such simulations because the fluids in the tank are in a range of different sub-critical and supercritical states and elaborate phase change and mixing rules have to be developed to accurately model the interaction between the ullage gas and the propellant. We show a typical run-time simulation of a spherical propellant tank, containing RP-1 in this case, being pressurized with room-temperature nitrogen at 540 R. Nitrogen

  20. New Delivery Systems and Propellants

    Directory of Open Access Journals (Sweden)

    Myrna Dolovich

    1999-01-01

    Full Text Available The removal of chlorofluorocarbon (CFC propellants from industrial and household products has been agreed to by over 165 countires of which more than 135 are developing countries. The timetable for this process is outlined in the Montreal Protocol on Substances that Deplete the Ozone Layer document and in several subsequent amendments. Pressured metered dose inhalers (pMDIs for medical use have been granted temporary exemptions until replacement formulations, providing the same medication via the same route, and with the same efficacy and safety profiles, are approved for human use. Hydrofluoroalkanes (HFAs are the alternative propellants for CFCs-12 and -114. Their potential for damage to the ozone layer is nonexistent, and while they are greenhouse gases, their global warming potential is a fraction (one-tenth of that of CFCs. Replacement formulations for almost all inhalant respiratory medications have been or are being produced and tested; in Canada, it is anticipated that the transition to these HFA or CFC-free pMDIs will be complete by the year 2005. Initially, an HFA pMDI was to be equivalent to the CFC pMDI being replaced, in terms of aerosol properties and effective clinical dose. However, this will not necessarily be the situation, particularly for some corticosteroid products. Currently, only one CFC-free formulation is available in Canada – Airomir, a HFA salbutamol pMDI. This paper discusses the in vitro aerosol characteristics, in vivo deposition and clinical data for several HFA pMDIs for which there are data available in the literature. Alternative delivery systems to the pMDI, namely, dry powder inhalers and nebulizers, are briefly reviewed.

  1. Mars Ascent Vehicle-Propellant Aging

    Science.gov (United States)

    Dankanich, John; Rousseau, Jeremy; Williams, Jacob

    2015-01-01

    This project is to develop and test a new propellant formulation specifically for the Mars Ascent Vehicle (MAV) for the robotic Mars Sample Return mission. The project was initiated under the Planetary Sciences Division In-Space Propulsion Technology (ISPT) program and is continuing under the Mars Exploration Program. The two-stage, solid motor-based MAV has been the leading MAV solution for more than a decade. Additional studies show promise for alternative technologies including hybrid and bipropellant options, but the solid motor design has significant propellant density advantages well suited for physical constraints imposed while using the SkyCrane descent stage. The solid motor concept has lower specific impulse (Isp) than alternatives, but if the first stage and payload remain sufficiently small, the two-stage solid MAV represents a potential low risk approach to meet the mission needs. As the need date for the MAV slips, opportunities exist to advance technology with high on-ramp potential. The baseline propellant for the MAV is currently the carboxyl terminated polybutadiene (CTPB) based formulation TP-H-3062 due to its advantageous low temperature mechanical properties and flight heritage. However, the flight heritage is limited and outside the environments, the MAV must endure. The ISPT program competed a propellant formulation project with industry and selected ATK to develop a new propellant formulation specifically for the MAV application. Working with ATK, a large number of propellant formulations were assessed to either increase performance of a CTPB propellant or improve the low temperature mechanical properties of a hydroxyl terminated polybutadiene (HTPB) propellant. Both propellants demonstrated potential to increase performance over heritage options, but an HTPB propellant formulation, TP-H-3544, was selected for production and testing. The test plan includes propellant aging first at high vacuum conditions, representative of the Mars transit

  2. Energy coefficients for a propeller series

    DEFF Research Database (Denmark)

    Olsen, Anders Smærup

    2004-01-01

    The efficiency for a propeller is calculated by energy coefficients. These coefficients are related to four types of losses, i.e. the axial, the rotational, the frictional, and the finite blade number loss, and one gain, i.e. the axial gain. The energy coefficients are derived by use...... of the potential theory with the propeller modelled as an actuator disk. The efficiency based on the energy coefficients is calculated for a propeller series. The results show a good agreement between the efficiency based on the energy coefficients and the efficiency obtained by a vortex-lattice method....

  3. Shuttle APS propellant thermal conditioner study

    Science.gov (United States)

    Pearson, W. E.

    1971-01-01

    A study program was performed to allow selection of thermal conditioner assemblies for superheating O2 and H2 at supercritical pressures. The application was the auxiliary propulsion system (APS) for the space shuttle vehicle. The O2/H2 APS propellant feed system included propellant conditioners, of which the thermal conditioner assemblies were a part. Cryogens, pumped to pressures above critical, were directed to the thermal conditioner assembly included: (1) a gas generator assembly with ignition system and bipropellant valves, which burned superheated O2 and H2 at rich conditions; (2) a heat exchanger assembly for thermal conditioning of the cryogenic propellant; and (3) a dump nozzle for heat exchanger exhaust.

  4. Respiratory-Gated MRgHIFU in Upper Abdomen Using an MR-Compatible In-Bore Digital Camera

    Directory of Open Access Journals (Sweden)

    Vincent Auboiroux

    2014-01-01

    Full Text Available Objective. To demonstrate the technical feasibility and the potential interest of using a digital optical camera inside the MR magnet bore for monitoring the breathing cycle and subsequently gating the PRFS MR thermometry, MR-ARFI measurement, and MRgHIFU sonication in the upper abdomen. Materials and Methods. A digital camera was reengineered to remove its magnetic parts and was further equipped with a 7 m long USB cable. The system was electromagnetically shielded and operated inside the bore of a closed 3T clinical scanner. Suitable triggers were generated based on real-time motion analysis of the images produced by the camera (resolution 640×480 pixels, 30 fps. Respiratory-gated MR-ARFI prepared MRgHIFU ablation was performed in the kidney and liver of two sheep in vivo, under general anaesthesia and ventilator-driven forced breathing. Results. The optical device demonstrated very good MR compatibility. The current setup permitted the acquisition of motion artefact-free and high resolution MR 2D ARFI and multiplanar interleaved PRFS thermometry (average SNR 30 in liver and 56 in kidney. Microscopic histology indicated precise focal lesions with sharply delineated margins following the respiratory-gated HIFU sonications. Conclusion. The proof-of-concept for respiratory motion management in MRgHIFU using an in-bore digital camera has been validated in vivo.

  5. A Microperfusion and In-Bore Oxygenator System Designed for Magnetic Resonance Microscopy Studies on Living Tissue Explants

    Science.gov (United States)

    Flint, Jeremy J.; Menon, Kannan; Hansen, Brian; Forder, John; Blackband, Stephen J.

    2015-12-01

    Spectrometers now offer the field strengths necessary to visualize mammalian cells but were not designed to accommodate imaging of live tissues. As such, spectrometers pose significant challenges—the most evident of which are spatial limitations—to conducting experiments in living tissue. This limitation becomes problematic upon trying to employ commercial perfusion equipment which is bulky and—being designed almost exclusively for light microscopy or electrophysiology studies—seldom includes MR-compatibility as a design criterion. To overcome problems exclusive to ultra-high magnetic field environments with limited spatial access, we have designed microperfusion and in-bore oxygenation systems capable of interfacing with Bruker’s series of micro surface-coils. These devices are designed for supporting cellular resolution imaging in MR studies of excised, living tissue. The combined system allows for precise control of both dissolved gas and pH levels in the perfusate thus demonstrating applicability for a wide range of tissue types. Its compactness, linear architecture, and MR-compatible material content are key design features intended to provide a versatile hardware interface compatible with any NMR spectrometer. Such attributes will ensure the microperfusion rig’s continued utility as it may be used with a multitude of contemporary NMR systems in addition to those which are currently in development.

  6. Nano Icy Moons Propellant Harvester

    Science.gov (United States)

    VanWoerkom, Michael (Principal Investigator)

    2017-01-01

    As one of just a few bodies identified in the solar system with a liquid ocean, Europa has become a top priority in the search for life outside of Earth. However, cost estimates for exploring Europa have been prohibitively expensive, with estimates of a NASA Flagship class orbiter and lander approaching $5 billion. ExoTerra's NIMPH offers an affordable solution that can not only land, but return a sample from the surface to Earth. NIMPH combines solar electric propulsion (SEP) technologies being developed for the asteroid redirect mission and microsatellite electronics to reduce the cost of a full sample return mission below $500 million. A key to achieving this order-of-magnitude cost reduction is minimizing the initial mass of the system. The cost of any mission is directly proportional to its mass. By keeping the mission within the constraints of an Atlas V 551 launch vehicle versus an SLS, we can significantly reduce launch costs. To achieve this we reduce the landed mass of the sample return lander, which is the largest multiplier of mission mass, and shrink propellant mass through high efficiency SEP and gravity assists. The NIMPH projects first step in reducing landed mass focuses on development of a micro-In Situ Resource Utilization (micro-ISRU) system. ISRU allows us to minimize landed mass of a sample return mission by converting local ice into propellants. The project reduces the ISRU system to a CubeSat-scale package that weighs just 1.74 kg and consumes just 242 W of power. We estimate that use of this ISRU vs. an identical micro-lander without ISRU reduces fuel mass by 45 kg. As the dry mass of the lander grows for larger missions, these savings scale exponentially. Taking full advantage of the micro-ISRU system requires the development of a micro-liquid oxygen-liquid hydrogen engine. The micro-liquid oxygen-liquid hydrogen engine is tailored for the mission by scaling it to match the scale of the micro-lander and the low gravity of the target moon

  7. 14 CFR 35.23 - Propeller control system.

    Science.gov (United States)

    2010-01-01

    ... propeller effect under the intended operating conditions. (4) The failure or corruption of data or signals... corruption of airplane-supplied data does not result in hazardous propeller effects. (e) The propeller... effect. (2) Failures or malfunctions directly affecting the propeller control system in a typical...

  8. Mars Propellant Production with Ionic Liquids

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to develop a single vessel for carbon dioxide (CO2) capture and electrolysis for in situ Mars propellant production by eliminating several steps...

  9. Propellant-powered actuator for gas generators

    Science.gov (United States)

    Makowski, M. J.

    1972-01-01

    Hydrazine operated monopropellant generators are used for spacecraft rocket engines and propellant pressurization systems. Measured work output of monopropellant actuators compares favorably with output of squib-type actuators.

  10. In-Space Manufacture of Storable Propellants

    Data.gov (United States)

    National Aeronautics and Space Administration — Many deep-space, missions, especially those that return material or crews to near-Earth space, are severely limited by the need to carry propellants and heat shields...

  11. Mechanism of Combustion of Heterogeneous Solid Propellants

    National Research Council Canada - National Science Library

    Price, E

    1998-01-01

    ... (and compare results with those of AP oxidizer and Ap/hydrocarbon binder propellants). 4. Develop a realistic qualitative model of the combustion process that would identify the requirements for formulation of realistic analytical models.

  12. High Speed Compressor for Subcooling Propellants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The most promising propellant subcooling systems for LH2 require compression systems that involve development of significant head. The inlet pressure for these...

  13. Alternate Propellant Thermal Rocket, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Alternate Propellant Thermal Rocket (APTR) is a novel concept for propulsion of space exploration or orbit transfer vehicles. APTR propulsion is provided by...

  14. Some typical solid propellant rocket motors

    NARCIS (Netherlands)

    Zandbergen, B.T.C.

    2013-01-01

    Typical Solid Propellant Rocket Motors (shortly referred to as Solid Rocket Motors; SRM's) are described with the purpose to form a database, which allows for comparative analysis and applications in practical SRM engineering.

  15. High Speed Compressor for Subcooling Propellants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Propellant densification systems for LH2 require compression systems that develop significant head. In the past this has required multiple stages of compressors...

  16. Development and implementation of a propeller test capability for GL-10 "Greased Lightning" propeller design

    Science.gov (United States)

    Duvall, Brian Edward

    Interest in small unmanned aerial vehicles has increased dramatically in recent years. Hybrid vehicles which allow forward flight as a fixed wing aircraft and a true vertical landing capability have always had applications. Management of the available energy and noise associated with electric propeller propulsion systems presents many challenges. NASA Langley has developed the Greased Lightning 10 (GL-10) vertical takeoff, unmanned aerial vehicle with ten individual motors and propellers. All are used for propulsion during takeoff and contribute to acoustic noise pollution which is an identified nuisance to the surrounding users. A propeller test capability was developed to gain an understanding of how the noise can be reduced while meeting minimum thrust requirements. The designed propeller test stand allowed for various commercially available propellers to be tested for potential direct replacement of the current GL-10 propellers and also supported testing of a newly designed propeller provided by the Georgia Institute of Technology. Results from the test program provided insight as to which factors affect the noise as well as performance characteristics. The outcome of the research effort showed that the current GL-10 propeller still represents the best choice of all the candidate propellers tested.

  17. Small scale motor tests of ADN/GAP based propellants

    OpenAIRE

    Gettwert, Volker; Fischer, Sebastian

    2015-01-01

    Different ADN/GAP based propellants were evaluated as a potential replacement of the smoky AP based composite propellant and low signature double base propellants. The paper focuses on burning tests of propellants in a combustion chamber. The experimental results of an ADN/GAP, ADN/FOX12/GAP and Al/ADN/GAP propellant were compared with a standard Al/AP/HTPB propellant. In all cases the obtained experimental gravimetric specific impulse of the ADN/GAP based propellants were higher compared to ...

  18. Active Noise Control in Propeller Aircraft

    OpenAIRE

    Johansson, Sven; Claesson, Ingvar

    2001-01-01

    A noisy environment dominated by low frequency noise can often be improved through the use of active noise control. This situation arises naturally in propeller aircraft where the propellers induce periodic low frequency noise inside the cabin. The cabin noise is typically rather high, and the passenger flight comfort could be improved considerably if this level were significantly reduced. This paper addresses same design aspects for multiple-reference active noise control systems based on th...

  19. Fabrication of Propeller-Shaped Supra-amphiphile for Construction of Enzyme-Responsive Fluorescent Vesicles.

    Science.gov (United States)

    Li, Jie; Liu, Kaerdun; Han, Yuchun; Tang, Ben Zhong; Huang, Jianbin; Yan, Yun

    2016-10-04

    Propeller-shaped molecules have been recognized to display fantastic AIE (aggregation induced emission), but they can hardly self-assemble into nanostructures. Herein, we for the first time report that ionic complexation between a water-soluble tetrapheneyl derivative and an enzyme substrate in aqueous media produces a propeller-shaped supra-amphiphile that self-assembles into enzyme responsive fluorescent vesicles. The supra-amphiphile was fabricated upon complexation between a water-soluble propeller-shaped AIE luminogen TPE-BPA and myristoylcholine chloride (MChCl) in aqueous media. MChCl filled in the intramolecular voids of propeller-shaped TPE-BPA upon supra-amphiphile formation, which endows the supra-amphiphile superior self-assembling ability to the component molecules thus leading to the formation of fluorescent vesicles. Because MChCl is the substrate of cholinesterases, the vesicles dissemble in the presence of cholinesterases, and the fluorescent intensity can be correlated to the level of enzymes. The resulting fluorescent vesicles may be used to recognize the site of Alzheimer's disease, to encapsulate the enzyme inhibitor, and to release the inhibitor at the disease site.

  20. Water Contaminant Mitigation in Ionic Liquid Propellant

    Science.gov (United States)

    Conroy, David; Ziemer, John

    2009-01-01

    Appropriate system and operational requirements are needed in order to ensure mission success without unnecessary cost. Purity requirements applied to thruster propellants may flow down to materials and operations as well as the propellant preparation itself. Colloid electrospray thrusters function by applying a large potential to a room temperature liquid propellant (such as an ionic liquid), inducing formation of a Taylor cone. Ions and droplets are ejected from the Taylor cone and accelerated through a strong electric field. Electrospray thrusters are highly efficient, precise, scaleable, and demonstrate low thrust noise. Ionic liquid propellants have excellent properties for use as electrospray propellants, but can be hampered by impurities, owing to their solvent capabilities. Of foremost concern is the water content, which can result from exposure to atmosphere. Even hydrophobic ionic liquids have been shown to absorb water from the air. In order to mitigate the risks of bubble formation in feed systems caused by water content of the ionic liquid propellant, physical properties of the ionic liquid EMI-Im are analyzed. The effects of surface tension, material wetting, physisorption, and geometric details of the flow manifold and electrospray emitters are explored. Results are compared to laboratory test data.

  1. HMX based enhanced energy LOVA gun propellant.

    Science.gov (United States)

    Sanghavi, R R; Kamale, P J; Shaikh, M A R; Shelar, S D; Kumar, K Sunil; Singh, Amarjit

    2007-05-08

    Efforts to develop gun propellants with low vulnerability have recently been focused on enhancing the energy with a further improvement in its sensitivity characteristics. These propellants not only prevent catastrophic disasters due to unplanned initiation of currently used gun propellants (based on nitrate esters) but also realize enhanced energy levels to increase the muzzle velocity of the projectiles. Now, in order to replace nitroglycerine, which is highly sensitive to friction and impact, nitramines meet the requirements as they offer superior energy due to positive heat of formation, typical stoichiometry with higher decomposition temperatures and also owing to negative oxygen balance are less sensitive than stoichiometrically balanced NG. RDX has been widely reported for use in LOVA propellant. In this paper we have made an effort to present the work on scantily reported nitramine HMX based LOVA gun propellant while incorporating energetic plasticizer glycidyl azide polymer to enhance the energy level. HMX is known to be thermally stable at higher temperature than RDX and also proved to be less vulnerable to small scale shaped charge jet attack as its decomposition temperature is 270 degrees C. HMX also offers improved impulse due to its superior heat of formation (+17 kcal/mol) as compared to RDX (+14 kcal/mol). It has also been reported that a break point will not appear until 35,000 psi for propellant comprising of 5 microm HMX. Since no work has been reported in open literature regarding replacement of RDX by HMX, the present studies were carried out.

  2. Designing Small Propellers for Optimum Efficiency and Low Noise Footprint

    Science.gov (United States)

    2015-06-26

    successful model, it is recommended that the structure is sufficient to alleviate any torsion or bending of the propeller blade, a rapid prototype...investigate propeller design based on combined blade and momentum theory. It allows the design and analysis of propellers both on and off the design...performance of propeller-motor combinations . QMIL is a companion propeller design program. The aerodynamic models used in QPROP account for induced

  3. Propeller and inflow vortex interaction : vortex response and impact on the propeller performance

    NARCIS (Netherlands)

    Yang, Y.; Zhou, T; Sciacchitano, A.; Veldhuis, L.L.M.; Eitelberg, G.

    2016-01-01

    The aerodynamic operating conditions of a propeller can include complex situations where vorticity from sources upstream can enter the propeller plane. In general, when the vorticity enters in a concentrated form of a vortex, the interaction between the vortex and blade is referred to as

  4. 75 FR 51656 - Airworthiness Directives; Dowty Propellers R408/6-123-F/17 Model Propellers

    Science.gov (United States)

    2010-08-23

    ... between a propeller de-ice bus bar and the backplate assembly can cause failure of the bus bar and a consequent intermittent short circuit. Such a short circuit can cause a dual AC generator shutdown that... a propeller de-ice bus bar and the backplate assembly can cause failure of the bus bar and a...

  5. Thermal Vacuum Test Correlation of a Zero Propellant Load Case Thermal Capacitance Propellant Gauging Analytical Model

    Science.gov (United States)

    Mckim, Stephen A.

    2016-01-01

    This thesis describes the development and correlation of a thermal model that forms the foundation of a thermal capacitance spacecraft propellant load estimator. Specific details of creating the thermal model for the diaphragm propellant tank used on NASA's Magnetospheric Multiscale spacecraft using ANSYS and the correlation process implemented are presented. The thermal model was correlated to within plus or minus 3 degrees Celsius of the thermal vacuum test data, and was determined sufficient to make future propellant predictions on MMS. The model was also found to be relatively sensitive to uncertainties in applied heat flux and mass knowledge of the tank. More work is needed to improve temperature predictions in the upper hemisphere of the propellant tank where predictions were found to be 2 to 2.5 C lower than the test data. A road map for applying the model to predict propellant loads on the actual MMS spacecraft toward its end of life in 2017-2018 is also presented.

  6. A Detailed Historical Review of Propellant Management Devices for Low Gravity Propellant Acquisition

    Science.gov (United States)

    Hartwig, Jason W.

    2016-01-01

    This paper presents a comprehensive background and historical review of Propellant Management Devices (PMDs) used throughout spaceflight history. The purpose of a PMD is to separate liquid and gas phases within a propellant tank and to transfer vapor-free propellant from a storage tank to a transfer line en route to either an engine or receiver depot tank, in any gravitational or thermal environment. The design concept, basic flow physics, and principle of operation are presented for each type of PMD. The three primary capillary driven PMD types of vanes, sponges, and screen channel liquid acquisition devices are compared and contrasted. For each PMD type, a detailed review of previous applications using storable propellants is given, which include space experiments as well as space missions and vehicles. Examples of previous cryogenic propellant management are also presented.

  7. In-Space Propellant Production Using Water

    Science.gov (United States)

    Notardonato, William; Johnson, Wesley; Swanger, Adam; McQuade, William

    2012-01-01

    A new era of space exploration is being planned. Manned exploration architectures under consideration require the long term storage of cryogenic propellants in space, and larger science mission directorate payloads can be delivered using cryogenic propulsion stages. Several architecture studies have shown that in-space cryogenic propulsion depots offer benefits including lower launch costs, smaller launch vehicles, and enhanced mission flexibility. NASA is currently planning a Cryogenic Propellant Storage and Transfer (CPST) technology demonstration mission that will use existing technology to demonstrate long duration storage, acquisition, mass gauging, and transfer of liquid hydrogen in low Earth orbit. This mission will demonstrate key technologies, but the CPST architecture is not designed for optimal mission operations for a true propellant depot. This paper will consider cryogenic propellant depots that are designed for operability. The operability principles considered are reusability, commonality, designing for the unique environment of space, and use of active control systems, both thermal and fluid. After considering these operability principles, a proposed depot architecture will be presented that uses water launch and on orbit electrolysis and liquefaction. This could serve as the first true space factory. Critical technologies needed for this depot architecture, including on orbit electrolysis, zero-g liquefaction and storage, rendezvous and docking, and propellant transfer, will be discussed and a developmental path forward will be presented. Finally, use of the depot to support the NASA Science Mission Directorate exploration goals will be presented.

  8. Advances in LO2 Propellant Conditioning

    Science.gov (United States)

    Mehta, Gopal; Orth, Michael; Stone, William; Perry, Gretchen; Holt, Kimberly; Suter, John

    1994-01-01

    This paper describes the cryogenic testing and analysis that has recently been completed as part of a multi-year effort to develop a new, more robust and operable LO2 propellant conditioning system. Phase 1 of the program consisted of feasibility demonstrations ot four novel propellant conditioning concepts. A no-bleed, passive propellant conditioning option was shown for the first time to successfully provide desired propellant inlet conditions. The benefits of passive conditioning are reduced operations costs, decreased hardware costs, enhanced operability and increased reliability on future expendable launch vehicles In Phase 2 of the test program, effects of major design parameters were studied and design correlation for future vehicle design were developed. Simultaneously, analytical models were developed and validated. Over 100 tests were conducted with a full-scale feedline using LN2 as the test fluid. A circulation pump provided a range of pressure and flow conditions. The test results showed that the passive propellant conditioning system is insensitive to variations in many of the parameters. The test program provides the validation necessary to incorporate the passive conditioning system into the baseline of future vehicles. Modeling of these systems using computational fluid dynamics seems highly promising.

  9. Development of a Marine Propeller With Nonplanar Lifting Surfaces

    DEFF Research Database (Denmark)

    Andersen, Poul; Friesch, Jürgen; Kappel, Jens J.

    2005-01-01

    with higher efficiency and lower levels of noise and vibration excitation compared to conventional state-of-the-art propellers designed for the same task. Conventional and KAPPEL propellers have been compared for a medium-sized containership and a product tanker. In total, nine KAPPEL propellers and two...... conventional propellers have been designed, and models of all propellers have been examined with respect to cavitation and efficiency in the open-water and behind conditions. Casting procedures, measurement procedures, and stress analysis methods for the unconventional geometry of the KAPPEL propeller have...

  10. Electrostatic Discharge testing of propellants and primers

    Energy Technology Data Exchange (ETDEWEB)

    Berry, R.B.

    1994-02-01

    This report presents the results of testing of selected propellants and primers to Electrostatic Discharge (ESD) characteristic of the human body. It describes the tests and the fixturing built to accommodate loose material (propellants) and the packed energetic material of the primer. The results indicate that all powders passed and some primers, especially the electric primers, failed to pass established requirements which delineate insensitive energetic components. This report details the testing of components and materials to four ESD environments (Standard ESD, Severe ESD, Modified Standard ESD, and Modified Severe ESD). The purpose of this study was to collect data based on the customer requirements as defined in the Sandia Environmental Safety & Health (ES&H) Manual, Chapter 9, and to define static sensitive and insensitive propellants and primers.

  11. Elliptical field-of-view PROPELLER imaging.

    Science.gov (United States)

    Devaraj, Ajit; Pipe, James G

    2009-09-01

    Traditionally two-dimensional scans are designed to support an isotropic field-of-view (iFOV). When imaging elongated objects, significant savings in scan time can potentially be achieved by supporting an elliptical field-of-view (eFOV). This work presents an empirical closed-form solution to adapt the PROPELLER trajectory for an eFOV. The proposed solution is built on the geometry of the PROPELLER trajectory permitting the scan prescription and data reconstruction to remain largely similar to standard PROPELLER. The achieved FOV is experimentally validated by the point spread function (PSF) of a phantom scan. The details of potential savings in scan time and the signal-to-noise ratio (SNR) performance in comparison to iFOV scans for both phantom and in-vivo images are also described.

  12. Design and simulation on the morphing composite propeller (Conference Presentation)

    Science.gov (United States)

    Chen, Fanlong; Li, Qinyu; Liu, Liwu; Lan, Xin; Liu, Yanju; Leng, Jinsong

    2017-04-01

    As one of the most crucial part of the unmanned underwater vehicle (UUV), the composite propeller plays an important role on the UUV's performance. As the composite propeller behaves excellent properties in hydroelastic facet and acoustic suppression, it attracts increasing attentions all over the globe. This paper goes a step further based on this idea, and comes up with a novel concept of "morphing composite propeller" (MCP) to improve the performance of the conventional composite propeller (CCP) to anticipate the improved propeller can perform better to propel the UUV. Based on the new concept, a novel MCP is designed. Each blade of the propeller is assembled with an active rotatable flap (ARF) to change the blade's local camber with flap rotation. Then the transmission mechanism (TM) has been designed and housed in the propeller blade to push the ARF. With the ARF rotating, the UUV can be propelled by different thrusts under certain rotation velocities of the propeller. Based on the design, the Fluent is exploited to analyze the fluid dynamics around the propeller. Finally, based on the design and hydrodynamic analysis, the structural response for the novel morphing composite propeller is calculated. The propeller blade is simplified and layered with composite materials. And the structure response of an MCP is obtained with various rotation angle under the hydrodynamic pressure. This simulation can instruct the design and fabrication techniques of the MCP.

  13. Spectroscopy of Propellant-Related Flames

    Science.gov (United States)

    1990-06-01

    data. For propellant HMX1, the absorption data of Vanderhoff [12], the CARS data of Stufflebeam [13], and the CN LIF profile [4,5] can be compared...CARS experiments at 23 atm, Stufflebeam measured the concentration of N2, CO, H2 and temperature in an HMX1 propellant flame at distances about 1 mm...Parr, Hanson-Parr PLIF CN, NH, OH, NO, 10 NO2, T Stufflebeam CARS N2, CO, H2, T 13 Vanderhoff Absorption CN, NH, OH, T 12 Edwards LIF CN, NH, OH, T 4

  14. Innovative Swirl Injector for LOX and Hydrocarbon Propellants, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Gases trapped in the propellant feed lines of space-based rocket engines due to cryogenic propellant boil-off or pressurant ingestion can result in poor combustion...

  15. Innovative Swirl Injector for LOX and Hydrocarbon Propellants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Gases trapped in the propellant feed lines of space-based rocket engines due to cryogenic propellant boil-off or pressurant ingestion can result in poor combustion...

  16. Advanced insulation Materials for Cryogenic Propellant Storage Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Materials Technology, Inc (AMTI) responds to the Topic X9 entitled "Propulsion and Propellant Storage" under subtopic X9.01, "Long Term Cryogenic Propellant...

  17. Propellant Gelation for Green In-Space Propulsion, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Concerns in recent years about the toxicity and safe handling of the storable class of propellants have led to efforts in greener monopropellants and bi-propellants....

  18. Propellant Technologies: A Persuasive Wave of Future Propulsion Benefits

    Science.gov (United States)

    Palaszewski, Bryan; Ianovski, Leonid S.; Carrick, Patrick

    1997-01-01

    Rocket propellant and propulsion technology improvements can be used to reduce the development time and operational costs of new space vehicle programs. Advanced propellant technologies can make the space vehicles safer, more operable, and higher performing. Five technology areas are described: Monopropellants, Alternative Hydrocarbons, Gelled Hydrogen, Metallized Gelled Propellants, and High Energy Density Materials. These propellants' benefits for future vehicles are outlined using mission study results and the technologies are briefly discussed.

  19. A Submarine Electric Propulsion System with Large Hub Propeller

    Science.gov (United States)

    1983-05-01

    thrust coefficient n propeller rotational speed, revolutions per unit time Nb number of blades Pa ambient pressure SPv vapor pressure PI propeller pitch...propeller was better than that of the conventional propeller. The superior -46- S .. -. *.w• ".1[- propulsor cavitation performance indicated that the...presented here for a are unrealistically high since they assume a vapor pressure, Pv, of zero which for seawater at 59 0 F, ideally should be 2.50

  20. 14 CFR 35.2 - Propeller configuration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller configuration. 35.2 Section 35.2 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... components, including references to the relevant drawings and software design data, that define the type...

  1. Design Procedure of 4-Bladed Propeller

    African Journals Online (AJOL)

    PROF. O. E. OSUAGWU

    2013-09-01

    Sep 1, 2013 ... ... by converting rotational motion into thrust. A pressure difference is produced between the forward and the rear surfaces of the air foil-shaped blade, and a fluid (such as air or water) is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's principle and. Newton's third law.

  2. Atmospheric surveillance self-propelling device

    International Nuclear Information System (INIS)

    Cartoux, Gerard.

    1980-11-01

    The atmospheric surveillance self-propelling device of the Saclay Nuclear Research Center can, by its conception (autonomy, rapid put into service, multiplicity of sampling and measurements), be used for all kind of measuring campains: pollution radioactive or not, routine or accidental situation, technical and logistic support and as a coordination or investigation vehicle [fr

  3. Design Procedure of 4-Bladed Propeller

    African Journals Online (AJOL)

    PROF. O. E. OSUAGWU

    2013-09-01

    Sep 1, 2013 ... Diameter – The diameter of the imaginary cycle scribed by the blade ... Blade root – Fillet area. The region of transition from .... Propeller diameter. To estimate the weight of all blades and the polar moment of inertia of a blade, the approximate formula given by [8] was adopted. 3. 982.1. ,. YR. B. W. Weight.

  4. In-Bore 3-T MR-guided Transrectal Targeted Prostate Biopsy: Prostate Imaging Reporting and Data System Version 2-based Diagnostic Performance for Detection of Prostate Cancer.

    Science.gov (United States)

    Tan, Nelly; Lin, Wei-Chan; Khoshnoodi, Pooria; Asvadi, Nazanin H; Yoshida, Jeffrey; Margolis, Daniel J A; Lu, David S K; Wu, Holden; Sung, Kyung Hyun; Lu, David Y; Huang, Jaioti; Raman, Steven S

    2017-04-01

    Purpose To determine the diagnostic yield of in-bore 3-T magnetic resonance (MR) imaging-guided prostate biopsy and stratify performance according to Prostate Imaging Reporting and Data System (PI-RADS) versions 1 and 2. Materials and Methods This study was HIPAA compliant and institution review board approved. In-bore 3-T MR-guided prostate biopsy was performed in 134 targets in 106 men who (a) had not previously undergone prostate biopsy, (b) had prior negative biopsy findings with increased prostate-specific antigen (PSA) level, or (c) had a prior history of prostate cancer with increasing PSA level. Clinical, diagnostic 3-T MR imaging was performed with in-bore guided prostate biopsy, and pathology data were collected. The diagnostic yields of MR-guided biopsy per patient and target were analyzed, and differences between biopsy targets with negative and positive findings were determined. Results of logistic regression and areas under the curve were compared between PI-RADS versions 1 and 2. Results Prostate cancer was detected in 63 of 106 patients (59.4%) and in 72 of 134 targets (53.7%) with 3-T MR imaging. Forty-nine of 72 targets (68.0%) had clinically significant cancer (Gleason score ≥ 7). One complication occurred (urosepsis, 0.9%). Patients who had positive target findings had lower apparent diffusion coefficient values (875 × 10 -6 mm 2 /sec vs 1111 × 10 -6 mm 2 /sec, respectively; P PSA density (0.16 vs 0.10, respectively; P PI-RADS version 2 category 3-5 scores when compared with patients with negative target findings. MR targets with PI-RADS version 2 category 2, 3, 4, and 5 scores had a positive diagnostic yield of three of 23 (13.0%), six of 31 (19.4%), 39 of 50 (78.0%), and 24 of 29 (82.8%) targets, respectively. No differences were detected in areas under the curve for PI-RADS version 2 versus 1. Conclusion In-bore 3-T MR-guided biopsy is safe and effective for prostate cancer diagnosis when stratified according to PI-RADS versions 1 and 2

  5. A Portable Burn Pan for the Disposal of Excess Propellants

    Science.gov (United States)

    2015-11-01

    seconds from the charges becoming engaged to burnout . The surrounding grass was ignited by the radiant heat of the burn, an indication of the high...2) Opened propellant charges burning A.5) Propellant charges fully engaged A.6) Start of burn out Field Manual: CRREL Portable Propellant

  6. Main Factors Affecting Blade Failure of Marine Propeller(2nd Report:Resonance between Vibrations of Propeller Shaft and Blade)

    OpenAIRE

    川添, 強; 松尾, 信太郎; 錦戸, 真吾

    1994-01-01

    The first report showed the difficulty to consider the small material defects and the low fluctuating stress by the hydrodynamic force as the main factors of the propeller blade failure. For the purpose of the elucidation of resonance between vibrations of the propeller shaft and the propeller blade, this paper presents the measurements and calculations of the flexural natural frequency of the full scale propeller blade in .air and in water, the vibratory stress due to the resonance and the l...

  7. 75 FR 18774 - Airworthiness Directives; McCauley Propeller Systems Model 4HFR34C653/L106FA Propellers

    Science.gov (United States)

    2010-04-13

    ... done. (f) For propeller hubs with 6,000 or more operating hours time- since-new (TSN) on the effective... 6,000 operating hours TSN on the effective date of this AD, perform the procedures in paragraphs (h) through (k) of this AD before the propeller hub reaches 6,100 operating hours TSN. Onetime Propeller Hub...

  8. 75 FR 39801 - Airworthiness Directives; McCauley Propeller Systems Model 4HFR34C653/L106FA Propellers

    Science.gov (United States)

    2010-07-13

    ... done. (f) For propeller hubs with 6,000 or more operating hours time- since-new (TSN) on the effective... operating hours TSN on the effective date of this AD, perform the procedures in paragraphs (h) through (k) of this AD before the propeller hub reaches 6,100 operating hours TSN. Onetime Propeller Hub...

  9. Space Transportation Infrastructure Supported By Propellant Depots

    Science.gov (United States)

    Smitherman, David; Woodcock, Gordon

    2011-01-01

    A space transportation infrastructure is described that utilizes propellant depots to support all foreseeable missions in the Earth-Moon vicinity and deep space out to Mars. The infrastructure utilizes current expendable launch vehicles such as the Delta IV Heavy, Atlas V, and Falcon 9, for all crew, cargo, and propellant launches to orbit. Propellant launches are made to a Low-Earth-Orbit (LEO) Depot and an Earth-Moon Lagrange Point 1 (L1) Depot to support new reusable in-space transportation vehicles. The LEO Depot supports missions to Geosynchronous Earth Orbit (GEO) for satellite servicing, and to L1 for L1 Depot missions. The L1 Depot supports Lunar, Earth-Sun L2 (ESL2), Asteroid, and Mars missions. A Mars Orbital Depot is also described to support ongoing Mars missions. New concepts for vehicle designs are presented that can be launched on current 5-meter diameter expendable launch vehicles. These new reusable vehicle concepts include a LEO Depot, L1 Depot, and Mars Orbital Depot based on International Space Station (ISS) heritage hardware. The high-energy depots at L1 and Mars orbit are compatible with, but do not require, electric propulsion tug use for propellant and/or cargo delivery. New reusable in-space crew transportation vehicles include a Crew Transfer Vehicle (CTV) for crew transportation between the LEO Depot and the L1 Depot, a new reusable Lunar Lander for crew transportation between the L1 Depot and the lunar surface, and a Deep Space Habitat (DSH) to support crew missions from the L1 Depot to ESL2, Asteroid, and Mars destinations. A 6 meter diameter Mars lander concept is presented that can be launched without a fairing based on the Delta IV heavy Payload Planners Guide, which indicates feasibility of a 6.5 meter fairing. This lander would evolve to re-usable operations when propellant production is established on Mars. Figure 1 provides a summary of the possible missions this infrastructure can support. Summary mission profiles are presented

  10. Non-cavitating propeller noise modeling and inversion

    Science.gov (United States)

    Kim, Dongho; Lee, Keunhwa; Seong, Woojae

    2014-12-01

    Marine propeller is the dominant exciter of the hull surface above it causing high level of noise and vibration in the ship structure. Recent successful developments have led to non-cavitating propeller designs and thus present focus is the non-cavitating characteristics of propeller such as hydrodynamic noise and its induced hull excitation. In this paper, analytic source model of propeller non-cavitating noise, described by longitudinal quadrupoles and dipoles, is suggested based on the propeller hydrodynamics. To find the source unknown parameters, the multi-parameter inversion technique is adopted using the pressure data obtained from the model scale experiment and pressure field replicas calculated by boundary element method. The inversion results show that the proposed source model is appropriate in modeling non-cavitating propeller noise. The result of this study can be utilized in the prediction of propeller non-cavitating noise and hull excitation at various stages in design and analysis.

  11. On shear rheology of gel propellants

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Shai; Peretz, Arie [RAFAEL, MANOR Propulsion and Explosive Systems Division, Haifa (Israel); Natan, Benveniste [Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa (Israel)

    2007-04-15

    Selected fuel, oxidizer and simulant gels were prepared and rheologically characterized using a rotational rheometer. For fuel gelation both organic and inorganic gellants were utilized, whereas oxidizers and simulants were gelled with addition of silica and polysaccharides, respectively. The generalized Herschel-Bulkley constitutive model was found to most adequately represent the gels studied. Hydrazine-based fuels, gelled with polysaccharides, were characterized as shear-thinning pseudoplastic fluids with low shear yield stress, whereas inhibited red-fuming nitric acid (IRFNA) and hydrogen peroxide oxidizers, gelled with silica, were characterized as yield thixotropic fluids with significant shear yield stress. Creep tests were conducted on two rheological types of gels with different gellant content and the results were fitted by Burgers-Kelvin viscoelastic constitutive model. The effect of temperature on the rheological properties of gel propellant simulants was also investigated. A general rheological classification of gel propellants and simulants is proposed. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  12. Bistable (latching) solenoid actuated propellant isolation valve

    Science.gov (United States)

    Wichmann, H.; Deboi, H. H.

    1979-01-01

    The design, fabrication, assembly and test of a development configuration bistable (latching) solenoid actuated propellant isolation valve suitable for the control hydrazine and liquid fluorine to an 800 pound thrust rocket engine is described. The valve features a balanced poppet, utilizing metal bellows, a hard poppet/seat interface and a flexure support system for the internal moving components. This support system eliminates sliding surfaces, thereby rendering the valve free of self generated particles.

  13. Unsteady Processes in Solid Propellant Combustion,

    Science.gov (United States)

    1977-05-01

    0—AflO ~5a INSTITUTO NACIONAL DE TECNICA AEROESPACIAL MADRID (SPAIN) F/S 21/9.2UNSTEADY PROCESSES IN SOLID PROPELLANT COMBUSTION . (U) MAY...PRO C E SS E S IN SOLID P R O P E L L A N T C O M B U S T I O N H A. Crespo and M. Kindelán Instituto Nacional de Técnica Aeroespacial Madrid , Spain j

  14. Atomic hydrogen as a launch vehicle propellant

    Science.gov (United States)

    Palaszewski, Bryan A.

    1990-01-01

    An analysis of several atomic hydrogen launch vehicles was conducted. A discussion of the facilities and the technologies that would be needed for these vehicles is also presented. The Gross Liftoff Weights (GLOW) for two systems were estimated; their specific impulses (I sub sp) were 750 and 1500 lb(sub f)/s/lb(sub m). The atomic hydrogen launch vehicles were also compared to the currently planned Advanced Launch System design concepts. Very significant GLOW reductions of 52 to 58 percent are possible over the Advanced Launch System designs. Applying atomic hydrogen propellants to upper stages was also considered. Very high I(sub sp) (greater than 750 lb(sub f)/s/lb(sub m)) is needed to enable a mass savings over advanced oxygen/hydrogen propulsion. Associated with the potential benefits of high I(sub sp) atomic hydrogen are several challenging problems. Very high magnetic fields are required to maintain the atomic hydrogen in a solid hydrogen matrix. The magnetic field strength was estimated to be 30 kilogauss (3 Tesla). Also the storage temperature of the propellant is 4 K. This very low temperature will require a large refrigeration facility for the launch vehicle. The design considerations for a very high recombination rate for the propellant are also discussed. A recombination rate of 210 cm/s is predicted for atomic hydrogen. This high recombination rate can produce very high acceleration for the launch vehicle. Unique insulation or segmentation to inhibit the propellant may be needed to reduce its recombination rate.

  15. Bioconversion of Nitramine Propellant Wastewaters - Triaminoguanidine Nitrate

    Science.gov (United States)

    1985-01-01

    o d i m sulfide for sneerobiasis. Batch and continuous cultures were inoculated with organisar from activated sludge (Marlborough Easterly Sewage ...Treatmtnt Plant, Marlborough, IU) anaerobic sludge digest (Nut Island Sewage T r e a b n t Plant. Boston. MA) and garden roil. One aL sampler of... BIOCONVERSION OF NITRAMINE PROPELLANT WASTEWATERS = TRIAMINOGUANIDINE 0 a NITRATE 80 BY DAVID L KAPLAN AND ARTHUR M. KAPLAN JANUARY 1985

  16. Cryogenic Propellant Feed System Analytical Tool Development

    Science.gov (United States)

    Lusby, Brian S.; Miranda, Bruno M.; Collins, Jacob A.

    2011-01-01

    The Propulsion Systems Branch at NASA s Lyndon B. Johnson Space Center (JSC) has developed a parametric analytical tool to address the need to rapidly predict heat leak into propellant distribution lines based on insulation type, installation technique, line supports, penetrations, and instrumentation. The Propellant Feed System Analytical Tool (PFSAT) will also determine the optimum orifice diameter for an optional thermodynamic vent system (TVS) to counteract heat leak into the feed line and ensure temperature constraints at the end of the feed line are met. PFSAT was developed primarily using Fortran 90 code because of its number crunching power and the capability to directly access real fluid property subroutines in the Reference Fluid Thermodynamic and Transport Properties (REFPROP) Database developed by NIST. A Microsoft Excel front end user interface was implemented to provide convenient portability of PFSAT among a wide variety of potential users and its ability to utilize a user-friendly graphical user interface (GUI) developed in Visual Basic for Applications (VBA). The focus of PFSAT is on-orbit reaction control systems and orbital maneuvering systems, but it may be used to predict heat leak into ground-based transfer lines as well. PFSAT is expected to be used for rapid initial design of cryogenic propellant distribution lines and thermodynamic vent systems. Once validated, PFSAT will support concept trades for a variety of cryogenic fluid transfer systems on spacecraft, including planetary landers, transfer vehicles, and propellant depots, as well as surface-based transfer systems. The details of the development of PFSAT, its user interface, and the program structure will be presented.

  17. Simulating marine propellers with vortex particle method

    Science.gov (United States)

    Wang, Youjiang; Abdel-Maksoud, Moustafa; Song, Baowei

    2017-01-01

    The vortex particle method is applied to compute the open water characteristics of marine propellers. It is based on the large-eddy simulation technique, and the Smagorinsky-Lilly sub-grid scale model is implemented for the eddy viscosity. The vortex particle method is combined with the boundary element method, in the sense that the body is modelled with boundary elements and the slipstream is modelled with vortex particles. Rotational periodic boundaries are adopted, which leads to a cylindrical sector domain for the slipstream. The particle redistribution scheme and the fast multipole method are modified to consider the rotational periodic boundaries. Open water characteristics of three propellers with different skew angles are calculated with the proposed method. The results are compared with the ones obtained with boundary element method and experiments. It is found that the proposed method predicts the open water characteristics more accurately than the boundary element method, especially for high loading condition and high skew propeller. The influence of the Smagorinsky constant is also studied, which shows the results have a low sensitivity to it.

  18. Simulating the Composite Propellant Manufacturing Process

    Science.gov (United States)

    Williamson, Suzanne; Love, Gregory

    2000-01-01

    There is a strategic interest in understanding how the propellant manufacturing process contributes to military capabilities outside the United States. The paper will discuss how system dynamics (SD) has been applied to rapidly assess the capabilities and vulnerabilities of a specific composite propellant production complex. These facilities produce a commonly used solid propellant with military applications. The authors will explain how an SD model can be configured to match a specific production facility followed by a series of scenarios designed to analyze operational vulnerabilities. By using the simulation model to rapidly analyze operational risks, the analyst gains a better understanding of production complexities. There are several benefits of developing SD models to simulate chemical production. SD is an effective tool for characterizing complex problems, especially the production process where the cascading effect of outages quickly taxes common understanding. By programming expert knowledge into an SD application, these tools are transformed into a knowledge management resource that facilitates rapid learning without requiring years of experience in production operations. It also permits the analyst to rapidly respond to crisis situations and other time-sensitive missions. Most importantly, the quantitative understanding gained from applying the SD model lends itself to strategic analysis and planning.

  19. Experimental Study of Open Water Non-Series Marine Propeller Performance

    OpenAIRE

    M. A. Elghorab; A. Abou El-Azm Aly; A. S. Elwetedy; M. A. Kotb

    2013-01-01

    Later marine propeller is the main component of ship propulsion system. For a non-series propeller, it is difficult to indicate the open water marine propeller performance without an experimental study to measure the marine propeller parameters. In the present study, the open water performance of a non-series marine propeller has been carried out experimentally. The geometrical aspects of a commercial non-series marine propeller have been measured for a propeller blade ar...

  20. MR-sequences for prostate cancer diagnostics: validation based on the PI-RADS scoring system and targeted MR-guided in-bore biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Schimmoeller, Lars; Quentin, Michael; Buchbender, Christian; Antoch, Gerald; Blondin, Dirk [University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf (Germany); Arsov, Christian; Hiester, Andreas; Rabenalt, Robert; Albers, Peter [University Dusseldorf, Medical Faculty, Department of Urology, Dusseldorf (Germany)

    2014-10-15

    This study evaluated the accuracy of MR sequences [T2-, diffusion-weighted, and dynamic contrast-enhanced (T2WI, DWI, and DCE) imaging] at 3T, based on the European Society of Urogenital Radiology (ESUR) scoring system [Prostate Imaging Reporting and Data System (PI-RADS)] using MR-guided in-bore prostate biopsies as reference standard. In 235 consecutive patients [aged 65.7 ± 7.9 years; median prostate-specific antigen (PSA) 8 ng/ml] with multiparametric prostate MRI (mp-MRI), 566 lesions were scored according to PI-RADS. Histology of all lesions was obtained by targeted MR-guided in-bore biopsy. In 200 lesions, biopsy revealed prostate cancer (PCa). The area under the curve (AUC) for cancer detection was 0.70 (T2WI), 0.80 (DWI), and 0.74 (DCE). A combination of T2WI + DWI, T2WI + DCE, and DWI + DCE achieved an AUC of 0.81, 0.78, and 0.79. A summed PI-RADS score of T2WI + DWI + DCE achieved an AUC of 0.81. For higher grade PCa (primary Gleason pattern ≥ 4), the AUC was 0.85 for T2WI + DWI, 0.84 for T2WI + DCE, 0.86 for DWI + DCE, and 0.87 for T2WI + DWI + DCE. The AUC for T2WI + DWI + DCE for transitional-zone PCa was 0.73, and for the peripheral zone 0.88. Regarding higher-grade PCa, AUC for transitional-zone PCa was 0.88, and for peripheral zone 0.96. The combination of T2WI + DWI + DCE achieved the highest test accuracy, especially in patients with higher-grade PCa. The use of ≤2 MR sequences led to lower AUC in higher-grade and peripheral-zone cancers. (orig.)

  1. Measurement of Multiple Blade Rate Unsteady Propeller Forces

    Science.gov (United States)

    1990-05-01

    with PUF -2 prediction ...................................... 33 17. Total velocity measurement positions using LDV .................... 34 18...CRAW F OrIC TAB Q Propeller torque JU.tSw riced .,) Qn Amplitude of nth harmonic of torque By R Propeller tip radius Ot Itt:ic A.tdt 4Vt,.*, Cc#eS r...unsteady lifting surface theory code PUF -2, 3 and were compared with measured data. PUF -2 calculations were performed for both Propellers 4132 and

  2. Combustion of Solid Propellants (La Combustion des Propergols Solides)

    Science.gov (United States)

    1991-07-01

    Programme Abrege Lhistoire des propergols solides a connu un bouleversement profond avec la d~eouve:te pal Paul Vieille et Nobel, t la fin du dix...material Here again, double base and composite is not homogeneous, the flame front is not propellant behaviour will be analysed and plane. The web thickness... web in the aft regions) the propellant will all) propellants, there is a minimum cross- burn out unevenly, leading to a long pres- flow velocity below

  3. Tip Vortex Index (TVI) Technique for Inboard Propeller Noise Estimation

    OpenAIRE

    Sezen, Savaş; Dogrul, Ali; Bal, Şakir

    2018-01-01

    Cavitating marine propeller is one of the most dominant noise sources inmarine vessels.  The aim of this study isto examine the cavitating propeller noise induced by tip vortices for twinscrew passenger vessels. To determine the noise level inboard, tip vortex index(TVI) technique has been used. This technique is an approximate method based onnumerical and experimental data. In this study, it is aimed to predict theunderwater noise of a marine propeller by applying TVI technique for ...

  4. Computer aided design and development of mixed-propeller pumps

    International Nuclear Information System (INIS)

    Bhaoyal, B.C.

    1994-01-01

    This paper deals with the design principle of mixed propeller hydraulic aided by CADD software developed by author for generation of the hydraulic profile of the mixed propeller and diffuser geometry. The design methodology for plotting the vane profile of mixed propeller pump has been discussed in detail with special reference to conformal transformation in cylindrical as well as conical plane. (author). 10 refs., 11 figs

  5. Mitigating clogging and arrest in confined self-propelled systems

    Science.gov (United States)

    Savoie, William; Aguilar, Jeffrey; Monaenkova, Daria; Linevich, Vadim; Goldman, Daniel

    Ensembles of self-propelling elements, like colloidal surfers, bacterial biofilms, and robot swarms can spontaneously form density heterogeneities. To understand how to prevent potentially catastrophic clogs in task-oriented active matter systems (like soil excavating robots), we present a robophysical study of excavation of granular media in a confined environment. We probe the efficacy of two social strategies observed in our studies of fire ants (S. invicta). The first behavior (denoted as unequal workload) prescribes to each excavator a different probability to enter the digging area. The second behavior (denoted as reversal\\x9D), is characterized by a probability to forfeit excavation when progress is sufficiently obstructed. For equal workload distribution and no reversal behavior, clogs at the digging site prevent excavation for sufficient numbers of robots. Measurements of aggregation relaxation times reveal how the strategies mitigate clogs. The unequal workload behavior reduces the tunnel density, decreasing the probability of clog formation. Reversal behavior, while allowing clogs to form, reduces aggregation relaxation time. We posit that application of social behaviors can be useful for swarm robot systems where global control and organization may not be possible.

  6. CFD and FEM Model of an Underwater Vehicle Propeller

    Directory of Open Access Journals (Sweden)

    Chruściel Tadeusz

    2014-10-01

    Full Text Available Within the framework of the project for design and optimization of the Remotely Operated Vehicle (ROV, research on its propulsion has been carried out. Te entire project was supported by CFD and FEM calculations taking into account the characteristics of the underwater vehicle. One of the tasks was to optimize the semi-open duct for horizontal propellers, which provided propulsion and controllability in horizontal plane. In order to create a measurable model of this task it was necessary to analyze numerical methodology of propeller design, along with the structure of a propellers with nozzles and contra-rotating propellers. It was confronted with theoretical solutions which included running of the analyzed propeller near an underwater vehicle. Also preliminary qualitative analyses of a simplified system with contra-rotating propellers and a semi-open duct were carried out. Te obtained results enabled to make a decision about the ROVs duct form. Te rapid prototyping SLS (Selective Laser Sintering method was used to fabricate a physical model of the propeller. As a consequence of this, it was necessary to verify the FEM model of the propeller, which based on the load obtained from the CFD model. Te article contains characteristics of the examined ROV, a theoretical basis of propeller design for the analyzed cases, and the results of CFD and FEM simulations.

  7. Study on unsteady hydrodynamic performance of propeller in waves

    Science.gov (United States)

    Zhao, Qingxin; Guo, Chunyu; Su, Yumin; Liu, Tian; Meng, Xiangyin

    2017-09-01

    The speed of a ship sailing in waves always slows down due to the decrease in efficiency of the propeller. So it is necessary and essential to analyze the unsteady hydrodynamic performance of propeller in waves. This paper is based on the numerical simulation and experimental research of hydrodynamics performance when the propeller is under wave conditions. Open-water propeller performance in calm water is calculated by commercial codes and the results are compared to experimental values to evaluate the accuracy of the numerical simulation method. The first-order Volume of Fluid (VOF) wave method in STAR CCM+ is utilized to simulate the three-dimensional numerical wave. According to the above prerequisite, the numerical calculation of hydrodynamic performance of the propeller under wave conditions is conducted, and the results reveal that both thrust and torque of the propeller under wave conditions reveal intense unsteady behavior. With the periodic variation of waves, ventilation, and even an effluent phenomenon appears on the propeller. Calculation results indicate, when ventilation or effluent appears, the numerical calculation model can capture the dynamic characteristics of the propeller accurately, thus providing a significant theory foundation for further studying the hydrodynamic performance of a propeller in waves.

  8. High Impulse Nanoparticulate-Based Gel Propellants, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Small Business Innovative Research (SBIR) Phase I addresses the development of advanced gel propellants and determination of their suitability for...

  9. Evaluation of Raytek infrared pyrometer for continuous propellant temperature measurement

    Science.gov (United States)

    Dykstra, Mark D.

    1990-01-01

    The primary purpose of this evaluation was to determine if the Raytek IR pyrometer that was installed in the 600 gallon propellant mixers could be used to provide a continuous, accurate, reliable measurement of the propellant temperature during mixing. The Raytek infrared sensor is not recommended to be used for controlling propellant temperature nor for inspection buy-off. The first part of the evaluation was to determine the accuracy of the sensor in measuring the propellant temperature. The second part was to determine the reliability of the air purge design in preventing contamination of the IR window.

  10. Thermal Vacuum Test Correlation of A Zero Propellant Load Case Thermal Capacitance Propellant Gauging Analytics Model

    Science.gov (United States)

    McKim, Stephen A.

    2016-01-01

    This thesis describes the development and test data validation of the thermal model that is the foundation of a thermal capacitance spacecraft propellant load estimator. Specific details of creating the thermal model for the diaphragm propellant tank used on NASA's Magnetospheric Multiscale spacecraft using ANSYS and the correlation process implemented to validate the model are presented. The thermal model was correlated to within plus or minus 3 degrees Centigrade of the thermal vacuum test data, and was found to be relatively insensitive to uncertainties in applied heat flux and mass knowledge of the tank. More work is needed, however, to refine the thermal model to further improve temperature predictions in the upper hemisphere of the propellant tank. Temperatures predictions in this portion were found to be 2-2.5 degrees Centigrade lower than the test data. A road map to apply the model to predict propellant loads on the actual MMS spacecraft toward its end of life in 2017-2018 is also presented.

  11. 75 FR 7934 - Airworthiness Directives; McCauley Propeller Systems 1A103/TCM Series Propellers

    Science.gov (United States)

    2010-02-23

    ... with more than 1,500 operating hours time- since-new (TSN) or unknown operating hours TSN on the... TSN on the effective date of this AD, upon reaching 1,500 operating hours TSN or within the next 50... January 28, 2008, do the following: (1) For propellers with more than 1,500 operating hours TSN on the...

  12. Green Propellant Landing Demonstration at U.S. Range

    Science.gov (United States)

    Mulkey, Henry W.; Miller, Joseph T.; Bacha, Caitlin E.

    2016-01-01

    The Green Propellant Loading Demonstration (GPLD) was conducted December 2015 at Wallops Flight Facility (WFF), leveraging work performed over recent years to bring lower toxicity hydrazine replacement green propellants to flight missions. The objective of this collaboration between NASA Goddard Space Flight Center (GSFC), WFF, the Swedish National Space Board (SNSB), and Ecological Advanced Propulsion Systems (ECAPS) was to successfully accept LMP-103S propellant at a U.S. Range, store the propellant, and perform a simulated flight vehicle propellant loading. NASA GSFC Propulsion (Code 597) managed all aspects of the operation, handling logistics, preparing the procedures, and implementing the demonstration. In addition to the partnership described above, Moog Inc. developed an LMP-103S propellant-compatible titanium rolling diaphragm flight development tank and loaned it to GSFC to act as the GPLD flight vessel. The flight development tank offered the GPLD an additional level of flight-like propellant handling process and procedures. Moog Inc. also provided a compatible latching isolation valve for remote propellant expulsion. The GPLD operation, in concert with Moog Inc. executed a flight development tank expulsion efficiency performance test using LMP-103S propellant. As part of the demonstration work, GSFC and WFF documented Range safety analyses and practices including all elements of shipping, storage, handling, operations, decontamination, and disposal. LMP-103S has not been previously handled at a U.S. Launch Range. Requisite for this activity was an LMP-103S Risk Analysis Report and Ground Safety Plan. GSFC and WFF safety offices jointly developed safety documentation for application into the GPLD operation. The GPLD along with the GSFC Propulsion historical hydrazine loading experiences offer direct comparison between handling green propellant versus safety intensive, highly toxic hydrazine propellant. These described motives initiated the GPLD operation

  13. Green Propellant Loading Demonstration at U.S. Range

    Science.gov (United States)

    Mulkey, Henry W.; Miller, Joseph T.; Bacha, Caitlin E.

    2016-01-01

    The Green Propellant Loading Demonstration (GPLD) was conducted December 2015 at Wallops Flight Facility (WFF), leveraging work performed over recent years to bring lower toxicity hydrazine replacement green propellants to flight missions. The objective of this collaboration between NASA Goddard Space Flight Center (GSFC), WFF, the Swedish National Space Board (SNSB), and Ecological Advanced Propulsion Systems (ECAPS) was to successfully accept LMP-103S propellant at a U.S. Range, store the propellant, and perform a simulated flight vehicle propellant loading. NASA GSFC Propulsion (Code 597) managed all aspects of the operation, handling logistics, preparing the procedures, and implementing the demonstration. In addition to the partnership described above, Moog Inc. developed an LMP-103S propellant-compatible titanium rolling diaphragm flight development tank and loaned it to GSFC to act as the GPLD flight vessel. The flight development tank offered the GPLD an additional level of flight-like propellant handling process and procedures. Moog Inc. also provided a compatible latching isolation valve for remote propellant expulsion. The GPLD operation, in concert with Moog Inc. executed a flight development tank expulsion efficiency performance test using LMP-103S propellant. As part of the demonstration work, GSFC and WFF documented Range safety analyses and practices including all elements of shipping, storage, handling, operations, decontamination, and disposal. LMP-103S has not been previously handled at a U.S. Launch Range. Requisite for this activity was an LMP-103S Risk Analysis Report and Ground Safety Plan. GSFC and WFF safety offices jointly developed safety documentation for application into the GPLD operation. The GPLD along with the GSFC Propulsion historical hydrazine loading experiences offer direct comparison between handling green propellant versus safety intensive, highly toxic hydrazine propellant. These described motives initiated the GPLD operation

  14. Mars Propellant Liquefaction Modeling in Thermal Desktop

    Science.gov (United States)

    Desai, Pooja; Hauser, Dan; Sutherlin, Steven

    2017-01-01

    NASAs current Mars architectures are assuming the production and storage of 23 tons of liquid oxygen on the surface of Mars over a duration of 500+ days. In order to do this in a mass efficient manner, an energy efficient refrigeration system will be required. Based on previous analysis NASA has decided to do all liquefaction in the propulsion vehicle storage tanks. In order to allow for transient Martian environmental effects, a propellant liquefaction and storage system for a Mars Ascent Vehicle (MAV) was modeled using Thermal Desktop. The model consisted of a propellant tank containing a broad area cooling loop heat exchanger integrated with a reverse turbo Brayton cryocooler. Cryocooler sizing and performance modeling was conducted using MAV diurnal heat loads and radiator rejection temperatures predicted from a previous thermal model of the MAV. A system was also sized and modeled using an alternative heat rejection system that relies on a forced convection heat exchanger. Cryocooler mass, input power, and heat rejection for both systems were estimated and compared against sizing based on non-transient sizing estimates.

  15. TEMPERATURE PROFILES IN A PROPELLANT TANK

    Science.gov (United States)

    Danilowicz, R. L.

    1994-01-01

    A computer program has been developed which analyzes by means of mathematical models the temperature profiles in the contents of a filled propellant tank. In designing space vehicles using cryogenic liquid propellants, it is necessary to know how heat transferred from the tank walls and heat absorbed internally affect the temperature distribution with the tank contents. The mathematical flow model is based on results from small-scale experiments. The results showed that when a subcooled fluid is subject to both nonuniform internal heating and wall heating, two distinct temperature regions are developed. In the lower region, the fluid is thoroughly mixed and maintains a uniform temperature profile. In the upper region, a stratified layer develops, and a temperature gradient is formed from the accumulation of warm fluid from the boundary layer along the tank walls; it also indicated that the temperature profiles in the stratified layer exhibited similarity. This concept was developed primarily for internal heating caused by nuclear radiation. However, the theory and computer program are applicable for any form of internal or bulk heating. This program is written in FORTRAN IV for batch execution and has been implemented on the IBM 7094. This program was developed in 1970.

  16. Comparing Three Different Techniques for Magnetic Resonance Imaging-targeted Prostate Biopsies : A Systematic Review of In-bore versus Magnetic Resonance Imaging-transrectal Ultrasound fusion versus Cognitive Registration. Is There a Preferred Technique?

    NARCIS (Netherlands)

    Wegelin, Olivier; Melick, H.H.E.; Hooft, Lotty; Bosch, J L H Ruud; Reitsma, Hans B; Barentsz, Jelle O; Somford, Diederik M

    CONTEXT: The introduction of magnetic resonance imaging-guided biopsies (MRI-GB) has changed the paradigm concerning prostate biopsies. Three techniques of MRI-GB are available: (1) in-bore MRI target biopsy (MRI-TB), (2) MRI-transrectal ultrasound fusion (FUS-TB), and (3) cognitive registration

  17. Blade Section Lift Coefficients for Propellers at Extreme Off-Design Conditions

    National Research Council Canada - National Science Library

    Shen, Young

    1997-01-01

    The Propeller Force Module (PFM) code developed by Analytical Methods Inc. (AMI) for calculating propeller side forces during maneuvering simulation studies requires inputs of propeller blade sectional lift, drag, and moment data...

  18. Media Pedagogy: Media Education, Media Socialisation and Educational Media

    OpenAIRE

    Lars Qvortrup

    2007-01-01

    The aim of this paper is to examine the relationship between education and media. These two concepts can be combined in three ways: one can think of media education, i.e. education in the subject of mass media. One can think of media socialisation, i.e. education within the context of a media society in which pupils and students are experienced media users. Finally, one can think of educational media, i.e. media used for educational purposes. After having specified these three subject areas,...

  19. 76 FR 74749 - Critical Parts for Airplane Propellers

    Science.gov (United States)

    2011-12-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION... propellers. This action would define what a propeller critical part is, require the identification of... electronically. ] Mail: Send comments to Docket Operations, M-30; U.S. Department of Transportation (DOT), 1200...

  20. Design Procedure of 4-Bladed Propeller | Ishiodu | West African ...

    African Journals Online (AJOL)

    Marine propellers, although submerged in water aft of the ship, form an integral part of a ship and play a vital role in ship propulsion. Much has been said and published on the development of the marine propeller from the time of antiquity to the present age, but there is more to be done. Therefore, this paper focuses on the ...

  1. Current state of the art of HNF based composite propellants

    NARCIS (Netherlands)

    Ciucci, A.; Frota, O.; Welland, W.H.M.; Heijden, A.E.D.M. van der; Leeming, B.; Bellerby, J.M.; Brotzu, A.

    2004-01-01

    The main activities currently performed for the development of HNF-based propellants are presented. The objectives and approach adopted are described. The results obtained on the HNF decomposition mechanism and on the re- and co-crystallisation of HNF with potential propellant ingredients are

  2. Propeller flaps for lower-limb trauma | Rogers | South African ...

    African Journals Online (AJOL)

    The propeller flap has become a versatile and important component in our reconstructive algorithm following complex lower limb trauma. First described by Hyakusoku in 1991, it has since been adapted and modified by Hallock and Teo. This article outlines our experience specifically with perforator pedicled propeller flaps ...

  3. Self-propelled oil droplets consuming "fuel" surfactant

    DEFF Research Database (Denmark)

    Toyota, Taro; Maru, Naoto; Hanczyc, Martin M

    2009-01-01

    A micrometer-sized oil droplet of 4-octylaniline containing 5 mol % of an amphiphilic catalyst exhibited a self-propelled motion, producing tiny oil droplets, in an aqueous dispersion of an amphiphilic precursor of 4-octylaniline. The tiny droplets on the surface of the self-propelled droplet wer...

  4. 14 CFR 35.21 - Variable and reversible pitch propellers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Variable and reversible pitch propellers. 35.21 Section 35.21 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.21 Variable and...

  5. Prediction of propeller-induced hull-pressure fluctuations

    NARCIS (Netherlands)

    Van Wijngaarden, H.C.J.

    2011-01-01

    The cavitating propeller often forms the primary source of noise and vibration on board ships. The propeller induces hydroacoustic pressure fluctuations due to the passing blades and, more importantly, the dynamic activity of cavities in the propeller’s immediate vicinity. The accurate prediction of

  6. EFD and CFD Characterization of a CLT Propeller

    Directory of Open Access Journals (Sweden)

    Daniele Bertetta

    2012-01-01

    Full Text Available In the present paper an experimental and numerical analysis of an unconventional CLT propeller is carried out. Two different numerical approaches, a potential panel method and an RANSE solver, are employed. Cavitation tunnel experiments are carried out in order to measure, as usual, thrust, torque, and cavity extension for different propeller working points. Moreover, LDV measurements are performed to have a deep insight into the complex wake behind the propeller and to analyze the dynamics of generated tip vortexes. The numerical/experimental analysis and comparison of results highlight the peculiarities of this kind of propellers, the possibility to increase efficiency and reduce cavitation risk, in order to exploit the design approaches already well proven for conventional propellers also in the case of these unconventional geometries.

  7. Optimum design of B-series marine propellers

    Directory of Open Access Journals (Sweden)

    M.M. Gaafary

    2011-03-01

    Full Text Available The choice of an optimum marine propeller is one of the most important problems in naval architecture. This problem can be handled using the propeller series diagrams or regression polynomials. This paper introduces a procedure to find out the optimum characteristics of B-series marine propellers. The propeller design process is performed as a single objective function subjected to constraints imposed by cavitation, material strength and required propeller thrust. Although optimization software of commercial type can be adopted to solve the problem, the computer program that has been specially developed for this task may be more useful for its flexibility and possibility to be incorporated, as a subroutine, with the complex ship design process.

  8. Propellant development for the Advanced Solid Rocket Motor

    Science.gov (United States)

    Landers, L. C.; Stanley, C. B.; Ricks, D. W.

    1991-01-01

    The properties of a propellant developed for the NASA Advanced Solid Rocket Motor (ASRM) are described in terms of its composition, performance, and compliance to NASA specifications. The class 1.3 HTPB/AP/A1 propellant employs an ester plasticizer and the content of ballistic solids is set at 88 percent. Ammonia evolution is prevented by the utilization of a neutral bonding agent which allows continuous mixing. The propellant also comprises a bimodal AP blend with one ground fraction, ground AP of at least 20 microns, and ferric oxide to control the burning rate. The propellant's characteristics are discussed in terms of tradeoffs in AP particle size and the types of Al powder, bonding agent, and HTPB polymer. The size and shape of the ballistic solids affect the processability, ballistic properties, and structural properties of the propellant. The revised baseline composition is based on maximizing the robustness of in-process viscosity, structural integrity, and burning-rate tailoring range.

  9. Solid State MEMS Thrusters Using Electrically Controlled Extinguishable Solid Propellant, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ET Materials, LLC developed the first ever electrically controlled extinguishable solid propellant (ECESP). The original propellant developed under Air Force SBIR...

  10. MR-sequences for prostate cancer diagnostics: validation based on the PI-RADS scoring system and targeted MR-guided in-bore biopsy.

    Science.gov (United States)

    Schimmöller, Lars; Quentin, Michael; Arsov, Christian; Hiester, Andreas; Buchbender, Christian; Rabenalt, Robert; Albers, Peter; Antoch, Gerald; Blondin, Dirk

    2014-10-01

    This study evaluated the accuracy of MR sequences [T2-, diffusion-weighted, and dynamic contrast-enhanced (T2WI, DWI, and DCE) imaging] at 3T, based on the European Society of Urogenital Radiology (ESUR) scoring system [Prostate Imaging Reporting and Data System (PI-RADS)] using MR-guided in-bore prostate biopsies as reference standard. In 235 consecutive patients [aged 65.7 ± 7.9 years; median prostate-specific antigen (PSA) 8 ng/ml] with multiparametric prostate MRI (mp-MRI), 566 lesions were scored according to PI-RADS. Histology of all lesions was obtained by targeted MR-guided in-bore biopsy. In 200 lesions, biopsy revealed prostate cancer (PCa). The area under the curve (AUC) for cancer detection was 0.70 (T2WI), 0.80 (DWI), and 0.74 (DCE). A combination of T2WI + DWI, T2WI + DCE, and DWI + DCE achieved an AUC of 0.81, 0.78, and 0.79. A summed PI-RADS score of T2WI + DWI + DCE achieved an AUC of 0.81. For higher grade PCa (primary Gleason pattern ≥ 4), the AUC was 0.85 for T2WI + DWI, 0.84 for T2WI + DCE, 0.86 for DWI + DCE, and 0.87 for T2WI + DWI + DCE. The AUC for T2WI + DWI + DCE for transitional-zone PCa was 0.73, and for the peripheral zone 0.88. Regarding higher-grade PCa, AUC for transitional-zone PCa was 0.88, and for peripheral zone 0.96. The combination of T2WI + DWI + DCE achieved the highest test accuracy, especially in patients with higher-grade PCa. The use of ≤2 MR sequences led to lower AUC in higher-grade and peripheral-zone cancers. • T2WI + DWI + DCE achieved the highest accuracy in patients with higher grade PCa • T2WI + DWI + DCE was more accurate for peripheral- than for transitional-zone PCa • DCE increased PCa detection accuracy in the peripheral zone • DWI was the leading sequence in the transitional zone.

  11. Image based measurement techniques for aircraft propeller flow diagnostics : Propeller slipstream investigations at high-lift conditions and thrust reverse

    NARCIS (Netherlands)

    Roosenboom, E.W.M.

    2011-01-01

    The aim of the thesis is to measure the propeller slipstream properties (velocity and vorticity) and to assess the unsteady and instantaneous behavior of the propeller flow field at high disk loadings, zero thrust and thrust reverse using the image based measurement techniques. Along with its

  12. Relativistic Spacecraft Propelled by Directed Energy

    Science.gov (United States)

    Kulkarni, Neeraj; Lubin, Philip; Zhang, Qicheng

    2018-04-01

    Achieving relativistic flight to enable extrasolar exploration is one of the dreams of humanity and the long-term goal of our NASA Starlight program. We derive a relativistic solution for the motion of a spacecraft propelled by radiation pressure from a directed energy (DE) system. Depending on the system parameters, low-mass spacecraft can achieve relativistic speeds, thus enabling interstellar exploration. The diffraction of the DE system plays an important role and limits the maximum speed of the spacecraft. We consider “photon recycling” as a possible method to achieving higher speeds. We also discuss recent claims that our previous work on this topic is incorrect and show that these claims arise from an improper treatment of causality.

  13. Closed-cycle liquid propellant rocket engines

    Science.gov (United States)

    Kuznetsov, N. D.

    1993-06-01

    The paper presents experience gained by SSSPE TRUD in development of NK-33, NK-43, NK-39, and NK-31 liquid propellant rocket engines, which are reusable, closed-cycle type, working on liquid oxygen and kerosene. Results are presented showing the engine structure efficiency, configuration rationality, and optimal thrust values which provide the following specific parameters: specific vacuum impulses in the range 331-353 s (for NK-33 and NK-31 engines, respectively) and specific weight of about 8 kg/tf (NK-33 and NK-43 engines). The problems which occurred during engine development and the study of the main components of these engines are discussed. The important technical data, materials, methodology, and bench development data are presented for the gas generator, turbopump assembly, combustion chamber and full-scale engines.

  14. WOW: light print, light propel, light point

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Bañas, Andrew Rafael; Aabo, Thomas

    2012-01-01

    We are presenting so-called Wave-guided Optical Waveguides (WOWs) fabricated by two-photon polymerization and capable of being optically manipulated into any arbitrary orientation. By integrating optical waveguides into the structures we have created freestanding waveguides which can be positioned...... anywhere in a sample at any orientation using real-time 3D optical micromanipulation with six degrees of freedom. One of the key aspects of our demonstrated WOWs is the change in direction of in-coupled light and the marked increase in numerical aperture of the out-coupled light. Hence, each light...... propelled WOW can tap from a relatively broad incident beam and generate a much more tightly confined light at its tip. The presentation contains both numerical simulations related to the propagation of light through a WOW and preliminary experimental demonstrations on our BioPhotonics Workstation...

  15. Space shuttle aps propellant thermal conditioner study

    Science.gov (United States)

    Fulton, D. L.

    1973-01-01

    An analytical and experimental effort was completed to evaluate a baffle type thermal conditioner for superheating O2 and H2 at supercritical pressures. The thermal conditioner consisted of a heat exchanger and an integral reactor (gas generator) operating on O2/H2 propellants. Primary emphasis was placed on the hydrogen conditioner with some effort on the oxygen conditioner and a study completed of alternate concepts for use in conditioning oxygen. A hydrogen conditioner was hot fire tested under a range of conditions to establish ignition, heat exchange and response parameters. A parallel technology task was completed to further evaluate the integral reactor and heat exchanger with the side mounted electrical spark igniter.

  16. NUMERICAL STUDY ON THE WAKE EVOLUTION OF CONTRA-ROTATING PROPELLER IN PROPELLER OPEN WATER AND SELF-PROPULSION CONDITIONS

    Directory of Open Access Journals (Sweden)

    Kwang-Jun Paik

    2017-01-01

    Full Text Available In this study, the wake characteristics of a contra-rotating propeller (CRP were investigated using a numerical simulation. The numerical simulation was carried out with a Reynolds averaged Navier−Stokes equations solver. The numerical simulations were performed on CRPs in both propeller open water and self-propulsion conditions to investigate their wake evolution characteristics. To study the effect of the rudder on the wake in the self-propulsion condition, the numerical simulations with and without a rudder were compared. The evolution of the CRP wake was analysed through velocity and vorticity contours on one transverse plane between the forward and aft propellers and two transverse planes located downstream of the CRP. The variations of thrust and torque of the forward and aft propellers during one revolution of the CRP were compared to investigate the interaction between forward and aft propellers and the effect of a rudder.

  17. A new mucosal propeller flap (deep lingual artery axial propeller): the renaissance of lingual flaps.

    Science.gov (United States)

    Cordova, Adriana; Toia, Francesca; D'Arpa, Salvatore; Giunta, Gabriele; Moschella, Francesco

    2015-03-01

    Lingual flaps provide ideal mucosal coverage for intraoral defects but traditionally require two surgical stages. The authors present an axial mucosal propeller flap for single-stage intraoral reconstruction. The flap includes the mucosa of the lateral side of the tongue, islanded on the deep lingual vessels. Between 2011 and 2013, 23 patients underwent intraoral mucosal reconstruction with a deep lingual artery axial propeller flap after cancer resection in the cheek (n = 16), floor of the mouth (n = 2), retromolar trigone (n = 2), hard palate (n = 2), and soft palate (n = 1). Mean defect size was 19.5 cm. Preoperative and postoperative intraoral function was evaluated with the Functional Intraoral Glasgow Scale. The authors always achieved one-stage reconstruction with primary donor-site closure. The only complications were an infection treated conservatively and a late oronasal fistula caused by radiotherapy. All patients resumed an oral diet after 1 week and none required surgical revision. Mean 12-month postoperative Functional Intraoral Glasgow Scale score was better than the preoperative score (13.5 versus 12.8). The deep lingual artery axial propeller flap combines the advantages of the traditional lingual flap (i.e., reliable axial vascularization and like-with-like reconstruction) with those of a propeller flap (i.e., one-stage transfer of like tissue and extreme mobility) and has wider indications than a conventional lingual flap. The technique is fast and has low morbidity and good functional results, and the authors recommend it as a first-choice technique to reconstruct moderate to large intraoral defects. Therapeutic, IV.

  18. Crusader solid propellant best technical approach

    Energy Technology Data Exchange (ETDEWEB)

    Graves, V. [Oak Ridge National Lab., TN (United States); Bader, G. [Fire Support Armament Center, Picatinny Arsenal, NJ (United States); Dolecki, M. [Tank-Automotive Research, Development, and Engineering Center, Picatinny, NJ (United States); Krupski, S. [Benet Weapons Lab., Watervliet Arsenal, NY (United States); Zangrando, R. [Close Combat Armament Center, Picatinny Arsenal, NJ (United States)

    1995-12-01

    The goal of the Solid Propellant Resupply Team is to develop Crusader system concepts capable of automatically handling 155mm projectiles and Modular Artillery Charges (MACs) based on system requirements. The system encompasses all aspects of handling from initial input into a resupply vehicle (RSV) to the final loading into the breech of the self-propelled howitzer (SPH). The team, comprised of persons from military and other government organizations, developed concepts for the overall vehicles as well as their interior handling components. An intermediate review was conducted on those components, and revised concepts were completed in May 1995. A concept evaluation was conducted on the finalized concepts, from both a systems level and a component level. The team`s Best Technical Approach (BTA) concept was selected from that evaluation. Both vehicles in the BTA have a front-engine configuration with the crew situated behind the engine-low in the vehicles. The SPH concept utilizes an automated reload port at the rear of the vehicle, centered high. The RSV transfer boom will dock with this port to allow automated ammunition transfer. The SPH rearm system utilizes fully redundant dual loaders. Active magazines are used for both projectiles and MACs. The SPH also uses a nonconventional tilted ring turret configuration to maximize the available interior volume in the vehicle. This configuration can be rearmed at any elevation angle but only at 0{degree} azimuth. The RSV configuration is similar to that of the SPH. The RSV utilizes passive storage racks with a pick-and-place manipulator for handling the projectiles and active magazines for the MACs. A telescoping transfer boom extends out the front of the vehicle over the crew and engine.

  19. Electrochemically powered self-propelled electrophoretic nanosubmarines

    Science.gov (United States)

    Pumera, Martin

    2010-09-01

    In the past few years, we have witnessed rapid developments in the realization of the old nanotechnology dream, autonomous nanosubmarines. These nanomachines are self-powered, taking energy from their environment by electrocatalytic conversion of chemicals present in the solution, self-propelled by flux of the electrons within the submarine and the hydronium ions on the surface of the nanosub, powering it in the direction opposite to that of the flux of the hydronium. These nanosubmarines are responsive to external fields, able to follow complex magnetic patterns, navigate themselves in complex microfluidic channels, follow chemical gradients, carry cargo, and communicate with each other. This minireview focuses on a discussion of the fundamentals of the electrophoretic mechanism underlying the propulsion of this sort of nanosub, as well as a demonstration of the proof-of-concept capabilities of nanosubmarines.In the past few years, we have witnessed rapid developments in the realization of the old nanotechnology dream, autonomous nanosubmarines. These nanomachines are self-powered, taking energy from their environment by electrocatalytic conversion of chemicals present in the solution, self-propelled by flux of the electrons within the submarine and the hydronium ions on the surface of the nanosub, powering it in the direction opposite to that of the flux of the hydronium. These nanosubmarines are responsive to external fields, able to follow complex magnetic patterns, navigate themselves in complex microfluidic channels, follow chemical gradients, carry cargo, and communicate with each other. This minireview focuses on a discussion of the fundamentals of the electrophoretic mechanism underlying the propulsion of this sort of nanosub, as well as a demonstration of the proof-of-concept capabilities of nanosubmarines. In memory of Karel Zeman, Czech animator, who encouraged thousands of young people into science and technology, on the occasion of the 100th

  20. Media education.

    Science.gov (United States)

    Strasburger, Victor C

    2010-11-01

    The American Academy of Pediatrics recognizes that exposure to mass media (eg, television, movies, video and computer games, the Internet, music lyrics and videos, newspapers, magazines, books, advertising) presents health risks for children and adolescents but can provide benefits as well. Media education has the potential to reduce the harmful effects of media and accentuate the positive effects. By understanding and supporting media education, pediatricians can play an important role in reducing harmful effects of media on children and adolescents.

  1. Protest leadership in the age of social media

    NARCIS (Netherlands)

    Poell, T.; Abdulla, R.; Rieder, B.; Woltering, R.; Zack, L.

    2016-01-01

    This article challenges the idea that social media protest mobilization and communication are primarily propelled by the self-motivated sharing of ideas, plans, images, and resources. It shows that leadership plays a vital role in steering popular contention on key social platforms. This argument is

  2. Monitoring of chemical degradation in propellants using AOTF spectrometer

    Science.gov (United States)

    Feigley, Robert; Jin, Feng; Lorenzo, Jose; Soos, Jolanta; Trivedi, Sudhir

    2004-02-01

    Candidate weapon systems have conservative environmental and service life limits to ensure both performance reliability and ordnance safety. One important element that must be monitored is chemical indicators of propellant degradation. Chemical degradation of energetic compounds in propellants can result in reduced performance and potential instability and auto-ignition in extreme circumstances. The current method for testing for chemical indicators of propellant degradation consists of removing a missile from its sub, disassembling it, and performing HPLC testing. An improvement to the current system is to use near-infrared (NIR) spectral analysis to measure chemical indicators of propellant degradation. An AOTF multi-channel spectrometer with reflectance probes can simultaneously scan different areas of a propellant. A study has shown clear spectral differences in samples of M1MP propellant with two different concentrations of the chemical diphenyl amine (DPA). DPA is very similar to many important chemical indicators of propellant degradation. The spectral differences provide the basis for correlating spectral data to DPA concentration using a multivariate regression technique.

  3. A review of research in low earth orbit propellant collection

    Science.gov (United States)

    Singh, Lake A.; Walker, Mitchell L. R.

    2015-05-01

    This comprehensive review examines the efforts of previous researchers to develop concepts for propellant-collecting spacecraft, estimate the performance of these systems, and understand the physics involved. Rocket propulsion requires the spacecraft to expend two fundamental quantities: energy and propellant mass. A growing number of spacecraft collect the energy they need to execute propulsive maneuvers in-situ with solar panels. In contrast, every spacecraft using rocket propulsion has carried all of the propellant mass needed for the mission from the ground, which limits the range and mission capabilities. Numerous researchers have explored the concept of collecting propellant mass while in space. These concepts have varied in scale and complexity from chemical ramjets to fusion-driven interstellar vessels. Research into propellant-collecting concepts occurred in distinct eras. During the Cold War, concepts tended to be large, complex, and nuclear powered. After the Cold War, concepts transitioned to solar power sources and more effort has been devoted to detailed analysis of specific components of the propellant-collecting architecture. By detailing the major contributions and limitations of previous work, this review concisely presents the state-of-the-art and outlines five areas for continued research. These areas include air-compatible cathode technology, techniques to improve propellant utilization on atmospheric species, in-space compressor and liquefaction technology, improved hypersonic and hyperthermal free molecular flow inlet designs, and improved understanding of how design parameters affect system performance.

  4. Calibration data for improved correction of UVW propeller anemometers

    Science.gov (United States)

    Connell, J. R.; Morris, V. R.

    1991-10-01

    Wind turbine test programs sponsored by the US DOE in the late 1980s called for measurement of three-dimensional turbulent wind with an accuracy not previously required. The Pacific Northwest Laboratory identified the need for more complete, more highly resolved, and more accurate calibrations to provide the new level of measurement capability. The UVW propeller anemometer, became the object of a unique calibration effort at a large wind tunnel at Colorado State University. A UVW anemometer, with all three propellers active, was installed in the wind tunnel on a digitally stepped two-axis rotary platform placed just below the tunnel floor. The azimuth and elevation of the anemometer in a steady wind at each of a selected set of speeds was stepped through a complete test program using a digital computer as controller and a digital data acquisition system to sample and filter the data. Tests were run using polypropylene and carbon fiber propellers. In addition, the effects of attaching 'shaft extensions' to the polypropylene propellers were measured. Calibrations for the polypropylene four-blade propeller provide an improved level of detail and repeatability. The UVW propeller anemometer is quite accurate at all wind angles and speeds to be experienced in wind energy studies, including winds blowing at right angles to the axis of rotation of a propeller. The new correction factors derived from these data eliminate previous difficulties in accuracy and speed of data reduction from voltages to wind speed components. Calibration data for a carbon fiber thermoplastic propeller are presented with resolution similar to that for the polypropylene propellers.

  5. Discovery Of B Ring Propellers In Cassini UVIS, And ISS

    Science.gov (United States)

    Sremcevic, Miodrag; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2012-10-01

    We present evidence for the existence of propellers in Saturn's B ring by combining data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We identify two propeller populations: (1) tens of degrees wide propellers in the dense B ring core, and (2) smaller, more A ring like, propellers populating the inner B ring. The prototype of the first population is an object observed at 18 different epochs between 2005 and 2010. The ubiquitous propeller "S" shape is seen both in UVIS occultations as an optical depth depletion and in ISS as a 40 degrees wide bright stripe in unlit geometries and dark in lit geometries. Combining the available Cassini data we infer that the object is a partial gap embedded in the high optical depth region of the B ring. The gap moves at orbital speed consistent with its radial location. From the radial separation of the propeller wings we estimate that the embedded body, which causes the propeller structure, is about 1.5km in size located at a=112,921km. The UVIS occultations indicate an asymmetric propeller "S" shape. Since the object is located at an edge between high and relatively low optical depth, this asymmetry is most likely a consequence of the strong surface mass density gradient. We estimate that there are possibly dozen up to 100 other propeller objects in Saturn's B ring. The location of the discovered body, at an edge of a dense ringlet within the B ring, suggests a novel mechanism for the up to now illusive B ring irregular large-scale structure of alternating high and low optical depth ringlets. We propose that this B ring irregular structure may have its cause in the presence of many embedded bodies that shepherd the individual B ring ringlets.

  6. Enhanced propellant performance via environmentally friendly curable surface coating

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2017-06-01

    Full Text Available Surface coating of granular propellants is widely used in a multiplicity of propellants for small, medium and large caliber ammunition. All small caliber ball propellants exhibit burning progressivity due to application of effective deterrent coatings. Large perforated propellant grains have also begun utilizing plasticizing and impregnated deterrent coatings with the purpose of increasing charge weights for greater energy and velocity for the projectile. The deterrent coating and impregnation process utilizes volatile organic compounds (VOCs and hazardous air pollutants (HAPs which results in propellants that need to be forced air dried which impacts air quality. Propellants undergo temperature fluctuations during their life. Diffusion coefficients vary exponentially with variations in temperature. A small temperature increase can induce a faster migration, even over a short period of time, which can lead to large deviations in the concentration. This large concentration change in the ammunition becomes a safety or performance liability. The presence of both polymeric deterrents and nitroglycerin(NG in the nitrocellulose matrix and organic solvents leads to higher diffusion rates. This results in continued emissions of VOCs and HAPs. Conventional polymers tend to partition within the propellant matrix. In other words, localized mixing can occur between the polymer and underlying propellant. This is due to solvent induced softening of the polymer vehicle over the propellant grain. In effect this creates a path where migration can occur. Since nitrate esters, like NG, are relatively small, it can exude to the surface and create a highly unstable and dangerous situation for the warfighter. Curable polymers do not suffer from this partitioning due to “melting” because no VOC solvents are present. They remain surface coated. The small scale characterization testing, such as closed bomb testing, small scale sensitivity, thermal stability, and

  7. Advanced helium regulator for a fluorine propellant system

    Science.gov (United States)

    Wichmann, H.; Yankura, G.

    1976-01-01

    The space storable propulsion module is an advanced high performance (375 seconds Isp minimum) planetary spacecraft propulsion system with a mission life of 5-10 years. The propellants used are liquid fluorine and amine fuel. This application requires high pressure regulator accuracy to optimize propellant depletion characteristics. An advanced regulator concept was prepared which is compatible with both fuel and oxidizer and which features design concepts such as redundant bellows, all-metallic/ceramic construction, friction-free guidance of moving parts and gas damping. Computer simulation of the propulsion module performance over two mission profiles indicated satisfactory minimization of those propellant residual requirements imposed by regulator performance variables.

  8. Air propellers and their environmental problems on ACV's

    Science.gov (United States)

    Soley, D. H.

    The development of ACV blade protection against erosion, both on the propeller blade faces and leading edge, is considered. Polyurethane spray coating is now the standard protection applied to all Dowty Rotol propellers, with thicknesses from 0.015-0.020 on aircraft, and up to 0.080 on the ACV. The bolt-on guard reduced leading edge replacement time by 50 percent, and makes possible replacement in all weather conditions. Typical damage and repairs to ACV blades are discussed, and the propeller installation on the LCAC craft being built for the U.S. Navy is addressed.

  9. A Portable Burn Pan for the Disposal of Excess Propellants

    Science.gov (United States)

    2015-11-01

    combustible mass of the charges, less than 0.001% of the energetics in the burn pan ash, energetics concentration of less than 0.5% in the residual ash, and...slider (within the pan), the remaining propellant grains as well as those from several other opened bags were piled over the slider onto unopened bags...Total DNT mass in the M1 propellant used for the tests was 40.7 kg. Lead carbonate, at 1% of the propellant mass, is the only non- combustible component

  10. Atmospheric Processing Module for Mars Propellant Production

    Science.gov (United States)

    Muscatello, Anthony C.

    2014-01-01

    The multi-NASA center Mars Atmosphere and Regolith COllectorPrOcessor for Lander Operations (MARCO POLO) project was established to build and demonstrate a methaneoxygen propellant production system in a Mars analog environment. Work at the Kennedy Space Center (KSC) Applied Chemistry Laboratory is focused on the Atmospheric Processing Module (APM). The purpose of the APM is to freeze carbon dioxide from a simulated Martian atmosphere containing the minor components nitrogen, argon, carbon monoxide, and water vapor at Martian pressures (8 torr) by using dual cryocoolers with alternating cycles of freezing and sublimation. The resulting pressurized CO(sub 2) is fed to a methanation subsystem where it is catalytically combined with hydrogen in a Sabatier reactor supplied by the Johnson Space Center (JSC) to make methane and water vapor. We first used a simplified once-through setup and later employed a H(sub 2)CO(sub 2) recycling system to improve process efficiency. This presentation and paper will cover (1) the design and selection of major hardware items, such as the cryocoolers, pumps, tanks, chillers, and membrane separators, (2) the determination of the optimal cold head design and flow rates needed to meet the collection requirement of 88 g CO(sub 2) hr for 14 hr, (3) the testing of the CO(sub 2) freezer subsystem, and (4) the integration and testing of the two subsystems to verify the desired production rate of 31.7 g CH(sub 4) hr and 71.3 g H(sub 2)O hr along with verification of their purity. The resulting 2.22 kg of CH(sub 2)O(sub 2) propellant per 14 hr day (including O(sub 2) from electrolysis of water recovered from regolith, which also supplies the H(sub 2) for methanation) is of the scale needed for a Mars Sample Return mission. In addition, the significance of the project to NASAs new Mars exploration plans will be discussed.

  11. Media Komunitas dan Media Literacy

    Directory of Open Access Journals (Sweden)

    Pawito .

    2013-12-01

    Full Text Available Abstract:This essay deals with community media in relation to media literacy. After a short discussion on a number of community media characters is made the essay goes further with somewhat detail theoretical presumptions of the roles of media community with respect primarily to the development as Amartya Sen mentioned about. The author suggests that community media may play some significant roles in the development including (a disseminating information (from varieties of perspective, (b facilitating public discussion, (c helping to reach solutions of problems, (d encouraging participations, and (e encouraging the development of media literacy. Regarding the last point the author remarks that media community may have a dual-roles i.e facilitating community’s member in media participation and facilitating community’s member in media education.

  12. Propellant and Terrestrial Fuel Production from Atmospheric Carbon Dioxide Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Build and test in a relevant environment a Mars propellant production plant of an appropriate scale for an initial demonstration on Mars. It will produce sufficient...

  13. Propellant Preparation Laboratory Complex (Area1-21)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: Area 1-21 is an explosion resistant complex of nine cells built into the side of a granite ridge. Three solid propellant cutting cells are housed in the...

  14. Gelled Propellants for Reduced Temperature Operation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is responsive to NASA 2004 SBIR objectives (under Topic X6.05) seeking gelled propellant formulations "for long-duration missions involving low-power...

  15. Self-Propelled Hovercraft Based on Cold Leidenfrost Phenomenon

    Science.gov (United States)

    Shi, Meng; Ji, Xing; Feng, Shangsheng; Yang, Qingzhen; Lu, Tian Jian; Xu, Feng

    2016-06-01

    The Leidenfrost phenomenon of liquid droplets levitating and dancing when placed upon a hot plate due to propulsion of evaporative vapor has been extended to many self-propelled circumstances. However, such self-propelled Leidenfrost devices commonly need a high temperature for evaporation and a structured solid substrate for directional movements. Here we observed a “cold Leidenfrost phenomenon” when placing a dry ice device on the surface of room temperature water, based on which we developed a controllable self-propelled dry ice hovercraft. Due to the sublimated vapor, the hovercraft could float on water and move in a programmable manner through designed structures. As demonstrations, we showed that the hovercraft could be used as a cargo ship or a petroleum contamination collector without consuming external power. This phenomenon enables a novel way to utilize programmable self-propelled devices on top of room temperature water, holding great potential for applications in energy, chemical engineering and biology.

  16. Gun barrel erosion - Comparison of conventional and LOVA gun propellants

    NARCIS (Netherlands)

    Hordijk, A.C.; Leurs, O.

    2006-01-01

    The research department Energetic Materials within TNO Defence, Security and Safety is involved in the development and (safety and insensitive munitions) testing of conventional (nitro cellulose based) and thermoplastic elastomer (TPE) based gun propellants. Recently our testing capabilities have

  17. Dynamical Model of Rocket Propellant Loading with Liquid Hydrogen

    Data.gov (United States)

    National Aeronautics and Space Administration — A dynamical model describing the multi-stage process of rocket propellant loading has been developed. It accounts for both the nominal and faulty regimes of...

  18. Propellant Flow Actuated Piezoelectric Rocket Engine Igniter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Spark ignition of a bi-propellant rocket engine is a classic, proven, and generally reliable process. However, timing can be critical, and the control logic,...

  19. Propellant Flow Actuated Piezoelectric Rocket Engine Igniter, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Under a Phase 1 effort, IES successfully developed and demonstrated a spark ignition concept where propellant flow drives a very simple fluid mechanical oscillator...

  20. Model-based Diagnostics for Propellant Loading Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — The loading of spacecraft propellants is a complex, risky operation. Therefore, diagnostic solutions are neces- sary to quickly identify when a fault occurs, so that...

  1. Advances in Hypergolic Propellants: Ignition, Hydrazine, and Hydrogen Peroxide Research

    Directory of Open Access Journals (Sweden)

    Stephen M. Davis

    2014-01-01

    Full Text Available A review of the literature pertaining to hypergolic fuel systems, particularly using hydrazine or its derivatives and hydrogen peroxide, has been conducted. It has been shown that a large effort has been made towards minimizing the risks involved with the use of a toxic propellant such as the hydrazine. Substitution of hydrazines for nontoxic propellant formulations such as the use of high purity hydrogen peroxide with various types of fuels is one of the major areas of study for future hypergolic propellants. A series of criteria for future hypergolic propellants has been recommended, including low toxicity, wide temperature range applicability, short ignition delay, high specific impulse or density specific impulse, and storability at room temperature.

  2. Combustion of four composite propellants at subatmospheric pressures

    Energy Technology Data Exchange (ETDEWEB)

    Schoyer, H.F.R.; Korting, P.A.O.G.

    1983-08-01

    The combustion behavior of 4 composite propellants was investigated in the pressure region between 20 and 140 kPa and at temperature of -40, 25 and 50 C. The experimental technique is based upon a cigarette burning rocket motor connected to a vacuum system. All four propellants display a De Vieille burning rate law. The burning rate is strongly affected by composition, pressure, and temperature. Combustion instability predominantly occurs at pressures below 50 kPa. Frequency spectra, pressure amplitudes versus mean pressure, and frequency versus mean pressure were determined for all 12 cases. The propellant response function was estimated. From all propellants, ICT 201 seems to be the least susceptible to oscillatory combustion.

  3. Numerical Prediction of Hydromechanical Behaviour of Controllable Pitch Propeller

    Directory of Open Access Journals (Sweden)

    Saman Tarbiat

    2014-01-01

    Full Text Available The research described in this paper was carried out to predict hydrodynamic and frictional forces of controllable pitch propeller (CPP that bring about fretting problems in a blade bearing. The governing equations are Reynolds-averaged Navier-Stokes (RANS and are solved by OpenFOAM solver for hydrodynamic forces behind the ship’s wake. Frictional forces are calculated by practical mechanical formulae. Different advance velocities with constant rotational speed for blades are used to achieve hydrodynamic coefficients in open water and the wake behind the propeller. Results are compared at four different pitches. Detailed numerical results of 3D modelling of the propeller, hydrodynamic characteristics, and probability of the fretting motion in the propeller are presented. Results show that the probability of the fretting movement is related to the pitch.

  4. An Additively Manufactured Torch Igniter for Liquid Propellants

    Data.gov (United States)

    National Aeronautics and Space Administration — Consistent and reliable rocket engine ignition has yet to be proven through an additively manufactured torch igniter for liquid propellants. The coupling of additive...

  5. Advanced Insulation Materials for Cryogenic Propellant Storage Applications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Materials Technology, Inc responds to the NASA solicitation Topic X9 entitled "Propulsion and Propellant Storage" under subtopic X9-01, "Long Term Cryogenic...

  6. Feasibility Study on Cutting HTPB Propellants with Abrasive Water Jet

    Science.gov (United States)

    Jiang, Dayong; Bai, Yun

    2018-01-01

    Abrasive water jet is used to carry out the experiment research on cutting HTPB propellants with three components, which will provide technical support for the engineering treatment of waste rocket motor. Based on the reliability theory and related scientific research results, the safety and efficiency of cutting sensitive HTPB propellants by abrasive water jet were experimentally studied. The results show that the safety reliability is not less than 99.52% at 90% confidence level, so the safety is adequately ensured. The cooling and anti-friction effect of high-speed water jet is the decisive factor to suppress the detonation of HTPB propellant. Compared with pure water jet, cutting efficiency was increased by 5% - 87%. The study shows that abrasive water jets meet the practical use for cutting HTPB propellants.

  7. A new method for aerodynamic test of high altitude propellers

    Directory of Open Access Journals (Sweden)

    Xiying Gong

    Full Text Available A ground test system is designed for aerodynamic performance tests of high altitude propellers. The system is consisted of stable power supply, servo motors, two-component balance constructed by tension-compression sensors, ultrasonic anemometer, data acquisition module. It is loaded on a truck to simulate propellers’ wind-tunnel test for different wind velocities at low density circumstance. The graphical programming language LABVIEW for developing virtual instrument is used to realize the test system control and data acquisition. Aerodynamic performance test of a propeller with 6.8 m diameter was completed by using this system. The results verify the feasibility of the ground test method. Keywords: High altitude propeller, Ground test, Virtual instrument control system

  8. LNG systems for natural gas propelled ships

    Science.gov (United States)

    Chorowski, M.; Duda, P.; Polinski, J.; Skrzypacz, J.

    2015-12-01

    In order to reduce the atmospheric pollution generated by ships, the International Marine Organization has established Emission Controlled Areas. In these areas, nitrogen oxides, sulphur oxides and particulates emission is strongly controlled. From the beginning of 2015, the ECA covers waters 200 nautical miles from the coast of the US and Canada, the US Caribbean Sea area, the Baltic Sea, the North Sea and the English Channel. From the beginning of 2020, strong emission restrictions will also be in force outside the ECA. This requires newly constructed ships to be either equipped with exhaust gas cleaning devices or propelled with emission free fuels. In comparison to low sulphur Marine Diesel and Marine Gas Oil, LNG is a competitive fuel, both from a technical and economical point of view. LNG can be stored in vacuum insulated tanks fulfilling the difficult requirements of marine regulations. LNG must be vaporized and pressurized to the pressure which is compatible with the engine requirements (usually a few bar). The boil-off must be controlled to avoid the occasional gas release to the atmosphere. This paper presents an LNG system designed and commissioned for a Baltic Sea ferry. The specific technical features and exploitation parameters of the system will be presented. The impact of strict marine regulations on the system's thermo-mechanical construction and its performance will be discussed. The review of possible flow-schemes of LNG marine systems will be presented with respect to the system's cost, maintenance, and reliability.

  9. WOW: light print, light propel, light point

    Science.gov (United States)

    Glückstad, Jesper; Bañas, Andrew; Aabo, Thomas; Palima, Darwin

    2012-10-01

    We are presenting so-called Wave-guided Optical Waveguides (WOWs) fabricated by two-photon polymerization and capable of being optically manipulated into any arbitrary orientation. By integrating optical waveguides into the structures we have created freestanding waveguides which can be positioned anywhere in a sample at any orientation using real-time 3D optical micromanipulation with six degrees of freedom. One of the key aspects of our demonstrated WOWs is the change in direction of in-coupled light and the marked increase in numerical aperture of the out-coupled light. Hence, each light propelled WOW can tap from a relatively broad incident beam and generate a much more tightly confined light at its tip. The presentation contains both numerical simulations related to the propagation of light through a WOW and preliminary experimental demonstrations on our BioPhotonics Workstation. In a broader context, this research shows that optically trapped micro-fabricated structures can potentially help bridge the diffraction barrier. This structure-mediated paradigm may be carried forward to open new possibilities for exploiting beams from far-field optics down to the sub-wavelength domain.

  10. An ultra-high field strength MR image-guided robotic needle delivery system for in-bore small animal interventions.

    Science.gov (United States)

    Gravett, Matthew; Cepek, Jeremy; Fenster, Aaron

    2017-11-01

    The purpose of this study was to develop and validate an image-guided robotic needle delivery system for accurate and repeatable needle targeting procedures in mouse brains inside the 12 cm inner diameter gradient coil insert of a 9.4 T MR scanner. Many preclinical research techniques require the use of accurate needle deliveries to soft tissues, including brain tissue. Soft tissues are optimally visualized in MR images, which offer high-soft tissue contrast, as well as a range of unique imaging techniques, including functional, spectroscopy and thermal imaging, however, there are currently no solutions for delivering needles to small animal brains inside the bore of an ultra-high field MR scanner. This paper describes the mechatronic design, evaluation of MR compatibility, registration technique, mechanical calibration, the quantitative validation of the in-bore image-guided needle targeting accuracy and repeatability, and demonstrated the system's ability to deliver needles in situ. Our six degree-of-freedom, MR compatible, mechatronic system was designed to fit inside the bore of a 9.4 T MR scanner and is actuated using a combination of piezoelectric and hydraulic mechanisms. The MR compatibility and targeting accuracy of the needle delivery system are evaluated to ensure that the system is precisely calibrated to perform the needle targeting procedures. A semi-automated image registration is performed to link the robot coordinates to the MR coordinate system. Soft tissue targets can be accurately localized in MR images, followed by automatic alignment of the needle trajectory to the target. Intra-procedure visualization of the needle target location and the needle were confirmed through MR images after needle insertion. The effects of geometric distortions and signal noise were found to be below threshold that would have an impact on the accuracy of the system. The system was found to have negligible effect on the MR image signal noise and geometric distortion

  11. Self-Propelled Hovercraft Based on Cold Leidenfrost Phenomenon

    OpenAIRE

    Meng Shi; Xing Ji; Shangsheng Feng; Qingzhen Yang; Tian Jian Lu; Feng Xu

    2016-01-01

    The Leidenfrost phenomenon of liquid droplets levitating and dancing when placed upon a hot plate due to propulsion of evaporative vapor has been extended to many self-propelled circumstances. However, such self-propelled Leidenfrost devices commonly need a high temperature for evaporation and a structured solid substrate for directional movements. Here we observed a ?cold Leidenfrost phenomenon? when placing a dry ice device on the surface of room temperature water, based on which we develop...

  12. Viscous-Inviscid Coupling Methods for Advanced Marine Propeller Applications

    OpenAIRE

    Greve, Martin; Wöckner-Kluwe, Katja; Abdel-Maksoud, Moustafa; Rung, Thomas

    2012-01-01

    The paper reports the development of coupling strategies between an inviscid direct panel method and a viscous RANS method and their application to complex propeller ows. The work is motivated by the prohibitive computational cost associated to unsteady viscous flow simulations using geometrically resolved propellers to analyse the dynamics of ships in seaways. The present effort aims to combine the advantages of the two baseline methods in order to reduce the numerical effort without comprom...

  13. Technology for gelled liquid cryogenic propellants - Metallized hydrogen/aluminum

    Science.gov (United States)

    Starkovich, John; Palaszewski, Bryan

    1993-01-01

    The theoretical basis for solid-loaded or densified liquid hydrogen propellants for advanced space applications is outlined. Metallized propellants make it possible to increase the safety of propulsion systems as well as the payloads of future vehicles. Nanogellant formulated liquid hydrogen gels and other fuel gels are characterized by excellent settling stability, low yield point, and a high shear thinning index which makes them attractive for propulsion applications.

  14. Outlook on marine propeller noise and cavitation modelling

    OpenAIRE

    Lidtke, Artur Konrad; Turnock, Stephen R.; Humphrey, Victor F.

    2014-01-01

    Two computational studies are presented in this paper. First, the Potsdam Propeller Test Case which is used to demonstrate the capabilities of mass transfer cavitation models, more precisely the model by Sauer and Schnerr, in tackling the problem of marine propeller cavitation. It is shown that the extents of the predicted cavitation regions agree well with the experiment but suffer from the fact that the tip vortices and the associated low pressure regions are under resolved when URANS is ut...

  15. Use of acoustic analogy for marine propeller noise characterisation

    OpenAIRE

    Lidtke, Artur Konrad; Turnock, Stephen; Humphrey, Victor

    2015-01-01

    Being able to predict shipborne noise is of significant importance to international maritime community. Porous Ffowcs-Williams Hawkings acoustic analogy is used with cavitation model by Sauer & Schnerr in order to predict the noise signature of the Potsdam Propeller operating in open water. The radiation pattern is shown to be predominantly affected by a dipole source, in addition to less prominent sources at the propeller plane and in the wake. It is shown that the predicted sound pressu...

  16. A fractional calculus perspective of distributed propeller design

    Science.gov (United States)

    Tenreiro Machado, J.; Galhano, Alexandra M.

    2018-02-01

    A new generation of aircraft with distributed propellers leads to operational performances superior to those exhibited by standard designs. Computational simulations and experimental tests show a reduction of fuel consumption and noise. This paper proposes an analogy between aerodynamics and electrical circuits. The model reveals properties similar to those of fractional-order systems and gives a deeper insight into the dynamics of multi-propeller coupling.

  17. PIV-based load determination in aircraft propellers

    OpenAIRE

    Ragni, D.

    2012-01-01

    The thesis describes the application of particle image velocimetry (PIV) to study the aerodynamic loads of airfoils and aircraft propellers. The experimental work focuses on the development of a measurement procedure to infer the pressure of the flow field from the velocity distribution obtained by PIV velocimetry. The technique offers important advantages in aircraft propellers, since the loads can be locally inspected without the need to install pressure sensors and momentum balances in rot...

  18. 75 FR 67613 - Airworthiness Directives; McCauley Propeller Systems Five-Blade Propeller Assemblies

    Science.gov (United States)

    2010-11-03

    ... propeller hubs from service before they exceed 6,000 hours time-since-new (TSN). This AD was prompted by a..., C5JFR36C1102/L114GCA-0, B5JFR36C1103/114HCA-0, or C5JFR36C1104/L114HCA-0, if the hub exceeds 6,000 hours TSN on.../L114GCA-0, B5JFR36C1103/114HCA-0, or C5JFR36C1104/L114HCA-0, if the hub has fewer than 6,000 hours TSN...

  19. Predictive power of the ESUR scoring system for prostate cancer diagnosis verified with targeted MR-guided in-bore biopsy.

    Science.gov (United States)

    Schimmöller, L; Quentin, M; Arsov, C; Hiester, A; Kröpil, P; Rabenalt, R; Albers, P; Antoch, G; Blondin, D

    2014-12-01

    This study evaluates the diagnostic value of the ESUR scoring system (PI-RADS) regarding prostate cancer detection using MR-guided in-bore biopsies (IB-GB) as the reference standard. 566 lesions in 235 consecutive patients (65.7 ± 7.9 years, PSA 9.9 ± 8.5 ng/ml) with a multiparametric (mp)-MRI (T2WI, DWI, DCE) of the prostate at 3T were scored using the PI-RADS scoring system. PI-RADS single (PSsingle), summed (PSsum), and overall (PSoverall) scores were determined. All lesions were histologically verified by IB-GB. Lesions with a PSsum below 9 contained no prostate cancer (PCa) with Gleason score (GS) ≥ 4+3=7. A PSsum of 13-15 (PSoverall V) resulted in 87.8% (n=108) in PCa and in 42.3% (n=52) in GS ≥ 4+3=7. Transition zone (TZ) lesions with a PSsum of 13-15 (PSoverall V) resulted in 76.3% (n=36) in PCa and in 26.3% (n=10) in GS ≥ 4+3=7, whereas for peripheral zone (PZ) lesions cancer detection rate at this score was 92.9% (n=79) and 49.4% (n=42) for GS ≥ 4+3=7. Using a threshold of PSsum ≥ 10, sensitivity was 86.0%, and negative predictive value (NPV) was 86.2%. For higher grade PCa sensitivity was 98.6%, and NPV was 99.5%. A PSsum below 9 excluded a higher grade PCa, whereas lesions with a PSsum ≥ 13 (PSoverall V) represented in 88% PCa, and in 42% higher grade PCa. The PSsum or PSoverall demonstrated a better diagnostic value for PZ lesions with higher detection rates for higher grade PCa compared to TZ lesions. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Effects of superhydrophobic surface on the propeller wake

    Science.gov (United States)

    Choi, Hongseok; Lee, Jungjin; Park, Hyungmin

    2017-11-01

    This study investigates the change in propeller wake when the superhydrophobic surface is applied on the propeller blade. The propeller rotates in a quiescent water tank, facing its bottom, with a rotational Reynolds number of 96000. To measure the three-dimensional flow fields, we use stereo PIV and a water prism is installed at the camera-side tank wall. Two cameras are tilted 30 degrees from the normal axis of the tank wall, satisfying schiempflug condition. Superhydrophobic surface is made by coating hydrophobic nanoparticles on the propeller blade. Measurements are done on two vertical planes (at the center of propeller hub and the blade tip), and are ensemble averaged being classified by blade phase of 0 and 90 degrees. Velocity fluctuation, turbulent kinetic energy, and vorticity are evaluated. With superhydrophobic surface, it is found that the turbulence level is significantly (20 - 30 %) reduced with a small penalty (less than 5%) in the streamwise momentum (i.e., thrust) generation. This is because the cone shaped propeller wake gets narrower and organized vortex structures are broken with the superhydrophobic surfaces. More detailed flow analysis will be given. Supported by NRF (NRF-2016R1C1B2012775, NRF-2016M2B2A9A02945068) programs of Korea government.

  1. Studies of pellet acceleration with arc discharge heated propellants

    International Nuclear Information System (INIS)

    Schuresko, D.D.

    1985-01-01

    An arc discharge has been utilized to heat gaseous propellants in a pneumatic pellet gun. A cylindrical arc chamber is interposed between the propellant inlet valve and the gun breech and fitted with a ceramic insert for generating swirl in the incoming gas stream. The arc is initiated after the propellant valve opens and the breech pressure starts to rise; a typical discharge lasts 300 microseconds with peak currents u to 2 kA at arc voltages ranging from 100 to 400 V. The system is instrumented with piezoelectric pressure transducers at the propellant valve outlet, gun breech, and gun muzzle. The gun has been operated with 4 mm diameter polyurethane foam pellets (density = 0.14 g/cm 3 ), a 40 cm-long barrel, and various gas propellants at pressures exceeding 70 bar. At I/sub arc/ = 1 kA, V/sub arc/ = 200 V, with helium propellant, the arc produces a 2 to 3 fold prompt increase in P/sub breech/ and a delayed increase in P/sub muzzle/; the pellets exit the gun from 0.5 to 1.0 ms earlier than with the gas alone at 40% higher speeds. Comparisons with the so-called ideal gun theory and with full one-dimensional hydrodynamic calculations of the pellet acceleration will be presented

  2. Numerical study of hub taper angle on podded propeller performance

    International Nuclear Information System (INIS)

    Islam, M.F.; Veitch, B.; Bose, N.; Liu, P.

    2005-01-01

    Presently, the majority of podded propulsion systems are of the pulling type, because this type provides better hydrodynamic efficiency than the pushing type. There are several possible explanations for the better overall performance of a puller type podded propulsor. One is related to the difference in hub shape. Puller and pusher propellers have opposite hub taper angles, hence different hub and blade root shape. These differences cause changes in the flow condition and possibly influence the overall performance. The current study focuses on the variation in performance of pusher and puller propellers with the same blade sections, but different hub taper angles. A hyperboloidal low order source doublet steady/unsteady time domain panel method code was modified and used to evaluate effects of hub taper angle on the open water propulsive performance of some fixed pitch screw propellers used in podded propulsion systems. The modified code was first validated against measurements of two model propellers in terms of average propulsive performance and good agreement was found. Major findings include significant effects of hub taper angle on propulsive performance of tapered hub propellers and noticeable effects of hub taper angle on sectional pressure distributions of tapered hub propeller blades. (author)

  3. Stereospecific Winding of Polycyclic Aromatic Hydrocarbons into Trinacria Propellers.

    Science.gov (United States)

    Mosca, Dario; Stopin, Antoine; Wouters, Johan; Demitri, Nicola; Bonifazi, Davide

    2017-11-02

    The stereospecific trimerization of enantiomerically pure binaphthols with hexakis(bromomethyl)benzene gives access in one step to enantiomerically pure molecular propellers, in which three binaphthyl rings are held together with dioxecine rings. X-ray diffraction analysis revealed that three out the six naphthyl moieties are folded in a (EF) 3 -type arrangement held by three intramolecular C-H⋅⋅⋅π interactions. This slips outward the three remaining naphthyl rings in a blade-like fashion, just like in three-folded propeller components. This peculiar conformation shows striking similarity to the mythological Sicilian symbol of Trinacria, from which the name "trinacria propeller" derives. The propeller conformation is also preserved in chlorinated solutions, as displayed by the presence of a peak at 4.7 ppm typical of an aromatic proton resonance engaged in a C-H⋅⋅⋅π interaction. The denaturation of the propeller-like conformation is obtained at high temperature, corresponding to activation energy for the ring inversion of ca. 18.2 kcal mol -1 . Notably, halide-functionalized molecular propellers exposing I-atoms at the leading and trailing edges could be prepared stereo- and regiospecifically by choosing the relevant iodo-bearing BINOL derivative. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. 4. Analysis of Three Dimensional Flow around Marine Propeller by Direct Formulation of Boundary Element Method

    OpenAIRE

    Zhi-Hao, LING; Yasuo, SASAKI; Michio, TAKAHASHI; Nippon Kaiji Kyokai; Nippon Kaiji Kyokai; Nippon Kaiji Kyokai

    1987-01-01

    In recent years, the fatigue fracture at the blade's root of propeller of motorcar carriers and refrigerated cargo carriers has become an important problem awaiting to be solved. Further the use of the highly skewed propeller for the reduction of ship vibration and noise leads to the strength problem of propeller. On the other hand, the demand for greater energy saving, lower propeller exciting forces and noise is growing more and more in the design of marine propeller. With such technical ba...

  5. Analysis of Three-Dimensional Flow around Marine Propeller by Direct Formulation of Boundary Element Method

    OpenAIRE

    Zhi-Hao, Ling; Yasuo, Sasaki; Michio, Takahashi; Research Institute; Research Institute; Research Institute

    1988-01-01

    In recent years, the fatigue fracture at the blade's root of propeller of motorcar carriers and refrigerated cargo carriers has become an important problem awaiting to be solved. Further the use of the highly skewed propeller for the reduction of ship vibration and noise leads to the strength problem of propeller. On the other hand, the demand for greater energy saving, lower propeller exciting forces and noise is growing more and more in the design of marine propeller. With such technical ba...

  6. Media Entrepreneurship

    DEFF Research Database (Denmark)

    Khajeheian, Datis

    2017-01-01

    Media Entrepreneurship has been an ambiguous, unclear and controversial concept and despite of growing academic efforts in the last decade, it is still a poorly defined subject. This paper is an effort to fill this gap by providing a comprehensive definition of media entrepreneurship. Firstly......, a literature review conducted and entrepreneurship, media, opportunity and innovation as building blocks of media entrepreneurship explained. Then by using of a mixed of bibliographic method and a Delphi method with multi-stage analysis process, a consensual definition of media entrepreneurship proposed...... entrepreneurship....

  7. Media Framing

    DEFF Research Database (Denmark)

    Pedersen, Rasmus T.

    2017-01-01

    The concept of media framing refers to the way in which the news media organize and provide meaning to a news story by emphasizing some parts of reality and disregarding other parts. These patterns of emphasis and exclusion in news coverage create frames that can have considerable effects on news...... consumers’ perceptions and attitudes regarding the given issue or event. This entry briefly elaborates on the concept of media framing, presents key types of media frames, and introduces the research on media framing effects....

  8. ANALISA PENGARUH ALIRAN FLUIDA YANG DITIMBULKAN OLEH GERAKAN PUTARAN PROPELLER PADA KAPAL IKAN TERHADAP TEKANAN PROPELLER DENGAN PENDEKATAN CFD

    Directory of Open Access Journals (Sweden)

    Samuel Samuel

    2012-04-01

    Full Text Available Dalam operasinya dilaut, suatu kapal harus memiliki kemampuan untuk mempertahankan kecepatan dinas (Vs seperti yang direncanakan. Hal ini mempunyai arti bahwa, kapal haruslah mempunyai rancangan sistem propulsi yang dapat mengatasi keseluruhan gaya-gaya hambat yang terjadi agar memenuhi standar kecepatan dinasnya. Penelitian untuk meningkatkan daya dorong propeller dari tahun ketahun terus dilakukan dengan meningkatakan efisiensi propeller. Tapi dari sisi lain usaha untuk meneliti dimana konsentrasi tegangan yang diakibatkan daya dorong propeller masih kurang dilakukan Untuk tugas akhir ini analisa yang dilakukan adalah untuk mengetahui distribusi tekanan pada propeller dan juga maximum stress yang terjadi pada propeller. Proses pembuatan model geometri dibantu dengan menggunakan software CAD dan analisanya dilakukan dengan mengunakan pendekatan CFD (Computational Fluid Dynamic sebagai sarana visualisasi.Analisa dilakukan dengan memvariasikan putaran propeller pada 100, 200, 300, 400, 500 rpm. Berdasarkan hasil perhitungan dan hasil running software CFD yang telah dilakukan didapatkan  hasil perbedaan tekanan dimana pada tiap putarannya semakin meningkat. Tekanan paling besar terjadi pada putaran 500 rpm yaiutu sebesar 28169,72 N. Dengan menggunakan software MSC NASTRAN didapatkan nilai maksimum strees sebesar 13,1 N/mm2 akan tetapi material ini masih dalam batas aman karena hasil perhitungan safety factor material bahan  didapat nilai 33,87.

  9. Propelling Exploration to the Moon and Beyond

    Science.gov (United States)

    Cook, Stephen A.

    2009-01-01

    As the Constellation Program enters its fourth year, the Ares Projects have made substantial progress toward sending human explorers beyond Earth orbit. The Ares I crew launch vehicle, which will take six astronauts or cargo to the International Space Station or four astronauts to rendezvous with Ares V for missions to the Moon, is the first human-rated vehicle NASA has developed in over 30 years. Since the Exploration Systems Architecture Study in 2005, the Ares Projects have completed a successful system requirements review, system definition review, and preliminary design review for the Ares I crew launch vehicle. The Ares I elements are well into development, beginning with the Shuttle-derived, five-segment solid rocket motor that will provide first-stage propulsion. The first stage team has poured its first production simulation article motor and will be pouring and firing the first five-segment development motor in 2009. Large-scale tooling has been installed and tested to produce propellant tanks for the liquid-fuel upper stage at Marshall Space Flight Center (MSFC) in Alabama. The initial upper stage units and main propulsion test article will be manufactured and tested at MSFC before transferring to Michoud Assembly Facility in Louisiana. The upper stage engine team has completed powerpack testing using Apollo J-2 heritage hardware and begun construction of a new altitude test stand at Stennis Space Center in Mississippi. The flight and integrated testing group has designed and built hardware for the Ares I-X test flight scheduled for 2009, as well as begun refurbishing existing infrastructure to support ground testing. Additionally, a base configuration has been selected for the Ares V cargo launch vehicle, which will send the Altair lunar lander and Orion to the Moon. Today, the Ares Projects are well on the way to building America s next generation of exploration-capable launch vehicles.

  10. Performance and slipstream characteristics of small-scale propellers at low Reynolds numbers

    Science.gov (United States)

    Deters, Robert W.

    The low Reynolds number effects of small-scale propellers were investigated. At the Reynolds numbers of interest (below 100,000), a decrease in lift and an increase in drag is common making it difficult to predict propeller performance characteristics. A propeller testing apparatus was built to test small scale propellers in static conditions and in an advancing flow. Twenty-seven off-the-shelf propellers, with diameters ranging from 2.25 in to 9 in, were tested in order to determine the general effects of low Reynolds numbers on small propellers. From these tests, increasing the Reynolds number for a propeller increases its efficiency by either increasing the thrust produced or decreasing the power. By doubling the Reynolds number of a propeller, it is not uncommon to increase the efficiency by more the 10%. Using off-the-shelf propellers limits the geometry available and finding propellers of the same geometry but of different scale is very difficult. To solve this problem, four propellers were design and built using a 3D printer. Two of the propellers were simple rectangular twisted blades of different chords. Another propeller was modeled after a full-scale propeller. The fourth propeller was created using inverse design to minimize power loss. Each propeller was built in a 5-in and 9-in diameter version in order to test a larger range of Reynolds numbers. A separate propeller blade and hub system was created to allow each propeller to be tested with different pitch angles and to test each propeller in a 2-, 3-, and 4-blade version. From the performance results of the 3D printed propellers, it was shown that propellers of different scale, but tested at the same Reynolds number, had about the same performance results. Finally, the slipstreams of different propellers were measured using a 7-hole probe. Propeller slipstreams can have a large effect on the aerodynamics of lifting surfaces downstream of the propeller. Small UAVs and MAVs flying in close proximity

  11. Characterization of Hall effect thruster propellant distributors with flame visualization

    Science.gov (United States)

    Langendorf, S.; Walker, M. L. R.

    2013-01-01

    A novel method for the characterization and qualification of Hall effect thruster propellant distributors is presented. A quantitative measurement of the azimuthal number density uniformity, a metric which impacts propellant utilization, is obtained from photographs of a premixed flame anchored on the exit plane of the propellant distributor. The technique is demonstrated for three propellant distributors using a propane-air mixture at reservoir pressure of 40 psi (gauge) (377 kPa) exhausting to atmosphere, with volumetric flow rates ranging from 15-145 cfh (7.2-68 l/min) with equivalence ratios from 1.2 to 2.1. The visualization is compared with in-vacuum pressure measurements 1 mm downstream of the distributor exit plane (chamber pressure held below 2.7 × 10-5 Torr-Xe at all flow rates). Both methods indicate a non-uniformity in line with the propellant inlet, supporting the validity of the technique of flow visualization with flame luminosity for propellant distributor characterization. The technique is applied to a propellant distributor with a manufacturing defect in a known location and is able to identify the defect and characterize its impact. The technique is also applied to a distributor with numerous small orifices at the exit plane and is able to resolve the resulting non-uniformity. Luminosity data are collected with a spatial resolution of 48.2-76.1 μm (pixel width). The azimuthal uniformity is characterized in the form of standard deviation of azimuthal luminosities, normalized by the mean azimuthal luminosity. The distributors investigated achieve standard deviations of 0.346 ± 0.0212, 0.108 ± 0.0178, and 0.708 ± 0.0230 mean-normalized luminosity units respectively, where a value of 0 corresponds to perfect uniformity and a value of 1 represents a standard deviation equivalent to the mean.

  12. Unsteady Aerodynamic Investigation of the Propeller-Wing Interaction for a Rocket Launched Unmanned Air Vehicle

    Directory of Open Access Journals (Sweden)

    G. Q. Zhang

    2013-01-01

    Full Text Available The aerodynamic characteristics of propeller-wing interaction for the rocket launched UAV have been investigated numerically by means of sliding mesh technology. The corresponding forces and moments have been collected for axial wing placements ranging from 0.056 to 0.5D and varied rotating speeds. The slipstream generated by the rotating propeller has little effects on the lift characteristics of the whole UAV. The drag can be seen to remain unchanged as the wing's location moves progressively closer to the propeller until 0.056D away from the propeller, where a nearly 20% increase occurred sharply. The propeller position has a negligible effect on the overall thrust and torque of the propeller. The efficiency affected by the installation angle of the propeller blade has also been analyzed. Based on the pressure cloud and streamlines, the vortices generated by propeller, propeller-wing interaction, and wing tip have also been captured and analyzed.

  13. Predictive power of the ESUR scoring system for prostate cancer diagnosis verified with targeted MR-guided in-bore biopsy

    International Nuclear Information System (INIS)

    Schimmöller, L.; Quentin, M.; Arsov, C.; Hiester, A.; Kröpil, P.; Rabenalt, R.; Albers, P.; Antoch, G.; Blondin, D.

    2014-01-01

    Highlights: • The PI-RADS summed score (PS sum ) demonstrated very good diagnostic values, especially for higher grade PCa. • Lesions with PS sum ≥13 represented prostate cancer in 88% and higher grade prostate cancer in 42%. • Sensitivity and NPV was nearly 100% for higher grade PCa detection using a cut-off limit of PS sum 10. • Peripheral zone lesions demonstrated better diagnostic value with the PS sum compared to transitional zone lesions. • Further improvement of the PI-RADS score is required to prevent unnecessary overdiagnosis. - Abstract: Purpose: This study evaluates the diagnostic value of the ESUR scoring system (PI-RADS) regarding prostate cancer detection using MR-guided in-bore biopsies (IB-GB) as the reference standard. Methods: 566 lesions in 235 consecutive patients (65.7 ± 7.9 years, PSA 9.9 ± 8.5 ng/ml) with a multiparametric (mp)-MRI (T2WI, DWI, DCE) of the prostate at 3 T were scored using the PI-RADS scoring system. PI-RADS single (PS single ), summed (PS sum ), and overall (PS overall ) scores were determined. All lesions were histologically verified by IB-GB. Results: Lesions with a PS sum below 9 contained no prostate cancer (PCa) with Gleason score (GS) ≥ 4 + 3 = 7. A PS sum of 13–15 (PS overall V) resulted in 87.8% (n = 108) in PCa and in 42.3% (n = 52) in GS ≥ 4 + 3 = 7. Transition zone (TZ) lesions with a PS sum of 13–15 (PS overall V) resulted in 76.3% (n = 36) in PCa and in 26.3% (n = 10) in GS ≥ 4 + 3 = 7, whereas for peripheral zone (PZ) lesions cancer detection rate at this score was 92.9% (n = 79) and 49.4% (n = 42) for GS ≥ 4 + 3 = 7. Using a threshold of PS sum ≥ 10, sensitivity was 86.0%, and negative predictive value (NPV) was 86.2%. For higher grade PCa sensitivity was 98.6%, and NPV was 99.5%. Conclusion: A PS sum below 9 excluded a higher grade PCa, whereas lesions with a PS sum ≥ 13 (PS overall V) represented in 88% PCa, and in 42% higher grade PCa. The PS sum or PS overall demonstrated a

  14. Media Flow

    DEFF Research Database (Denmark)

    Kabel, Lars

    2016-01-01

    News and other kinds of journalistic stories, 16-17 hours a day, all year round, on all platforms, also the moderated social media. The key research thesis behind this article is that the continuous and speedy stream of news stories and media content now is becoming the centre of the production...... processes and the value creation in converged multimedia newsrooms. The article identify new methods and discuss editorial challenges in handling media flow....

  15. Numerical simulation of unsteady propeller/rudder interaction

    Directory of Open Access Journals (Sweden)

    Lei He

    2017-11-01

    Full Text Available A numerical approach based on a potential flow method is developed to simulate the unsteady interaction between propeller and rudder. In this approach, a panel method is used to solve the flow around the rudder and a vortex lattice method is used to solve the flow around the propeller, respectively. An iterative procedure is adopted to solve the interaction between propeller and rudder. The effects of one component on the other are evaluated by using induced velocities due to the other component at every time step. A fully unsteady wake alignment algorithm is implemented into the vortex lattice method to simulate the unsteady propeller flow. The Rosenhead-Moore core model is employed during the wake alignment procedure to avoid the singularities and instability. The Lamb-Oseen vortex model is adopted in the present method to decay the vortex strength around the rudder and to eliminate unrealistically high induced velocity. The present methods are applied to predict the performance of a cavitating horn-type rudder in the presence of a 6-bladed propeller. The predicted cavity patterns compare well with those observed from the experiments.

  16. Rheokinetic Analysis of Hydroxy Terminated Polybutadiene Based Solid Propellant Slurry

    Directory of Open Access Journals (Sweden)

    Abhay K Mahanta

    2010-01-01

    Full Text Available The cure kinetics of propellant slurry based on hydroxy-terminated polybutadiene (HTPB and toluene diisocyanate (TDI polyurethane reaction has been studied by viscosity build up method. The viscosity (ɳ–time (t plots conform to the exponential function ɳ = aebt, where a & b are empirical constants. The rate constants (k for viscosity build up at various shear rate (rpm, evaluated from the slope of dɳ/dt versus ɳ plots at different temperatures, were found to vary from 0.0032 to 0.0052 min-1. It was observed that the increasing shear rate did not have significant effect on the reaction rate constants for viscosity build up of the propellant slurry. The activation energy (Eɳ, calculated from the Arrhenius plots, was found to be 13.17±1.78 kJ mole-1, whereas the activation enthalpy (∆Hɳ* and entropy (∆Sɳ* of the propellant slurry, calculated from Eyring relationship, were found to be 10.48±1.78 kJ mole-1 and –258.51± 5.38 J mole-1K-1, respectively. The reaction quenching temperature of the propellant slurry was found to be -9 ° C, based upon the experimental data. This opens up an avenue for a “freeze-and-store”, then “warm-up and cast”, mode of manufacturing of very large solid rocket propellant grains.

  17. Propellant-Flow-Actuated Rocket Engine Igniter

    Science.gov (United States)

    Wollen, Mark

    2013-01-01

    A rocket engine igniter has been created that uses a pneumatically driven hammer that, by specialized geometry, is induced into an oscillatory state that can be used to either repeatedly impact a piezoelectric crystal with sufficient force to generate a spark capable of initiating combustion, or can be used with any other system capable of generating a spark from direct oscillatory motion. This innovation uses the energy of flowing gaseous propellant, which by means of pressure differentials and kinetic motion, causes a hammer object to oscillate. The concept works by mass flows being induced through orifices on both sides of a cylindrical tube with one or more vent paths. As the mass flow enters the chamber, the pressure differential is caused because the hammer object is supplied with flow on one side and the other side is opened with access to the vent path. The object then crosses the vent opening and begins to slow because the pressure differential across the ball reverses due to the geometry in the tube. Eventually, the object stops because of the increasing pressure differential on the object until all of the kinetic energy has been transferred to the gas via compression. This is the point where the object reverses direction because of the pressure differential. This behavior excites a piezoelectric crystal via direct impact from the hammer object. The hammer strikes a piezoelectric crystal, then reverses direction, and the resultant high voltage created from the crystal is transferred via an electrode to a spark gap in the ignition zone, thereby providing a spark to ignite the engine. Magnets, or other retention methods, might be employed to favorably position the hammer object prior to start, but are not necessary to maintain the oscillatory behavior. Various manifestations of the igniter have been developed and tested to improve device efficiency, and some improved designs are capable of operation at gas flow rates of a fraction of a gram per second (0

  18. Flyer impact experiment to study vulnerability and reactivity of gun propellant formulations

    International Nuclear Information System (INIS)

    Bouma, R H B; Boluijt, A G; Verbeek, H J

    2009-01-01

    A flyer impact experiment to study the vulnerability of propellant formulations is designed. The shock wave conditions of the impacting flyer are related to the energy transfer from a single detonating propellant grain as found by numerical simulation. A propellant will react due to the imposed shock from the impacting flyer. The reactivity of the propellant formulation is quantified by the volume of the dent created in an aluminium witness block. This flyer impact experiment simulates the propellant grain-to-grain sympathetic reaction in a shaped charge attack on a gun propellant bed

  19. Flyer impact experiment to study vulnerability and reactivity of gun propellant formulations

    Science.gov (United States)

    Bouma, R. H. B.; Boluijt, A. G.; Verbeek, H. J.

    2009-09-01

    A flyer impact experiment to study the vulnerability of propellant formulations is designed. The shock wave conditions of the impacting flyer are related to the energy transfer from a single detonating propellant grain as found by numerical simulation. A propellant will react due to the imposed shock from the impacting flyer. The reactivity of the propellant formulation is quantified by the volume of the dent created in an aluminium witness block. This flyer impact experiment simulates the propellant grain-to-grain sympathetic reaction in a shaped charge attack on a gun propellant bed.

  20. Measurement of noise and its correlation to performance and geometry of small aircraft propellers

    Directory of Open Access Journals (Sweden)

    Štorch Vít

    2016-01-01

    Full Text Available A set of small model and UAV propellers is measured both in terms of aerodynamic performance and acoustic noise under static conditions. Apart from obvious correlation of noise to tip speed and propeller diameter the influence of blade pitch, blade pitch distribution, efficiency and shape of the blade is sought. Using the measured performance data a computational model for calculation of aerodynamic noise of propellers will be validated. The range of selected propellers include both propellers designed for nearly static conditions and propellers that are running at highly offdesign conditions, which allows to investigate i.e. the effect of blade stall on both noise level and performance results.

  1. Measurement of noise and its correlation to performance and geometry of small aircraft propellers

    Science.gov (United States)

    Štorch, Vít; Nožička, Jiří; Brada, Martin; Gemperle, Jiří; Suchý, Jakub

    2016-03-01

    A set of small model and UAV propellers is measured both in terms of aerodynamic performance and acoustic noise under static conditions. Apart from obvious correlation of noise to tip speed and propeller diameter the influence of blade pitch, blade pitch distribution, efficiency and shape of the blade is sought. Using the measured performance data a computational model for calculation of aerodynamic noise of propellers will be validated. The range of selected propellers include both propellers designed for nearly static conditions and propellers that are running at highly offdesign conditions, which allows to investigate i.e. the effect of blade stall on both noise level and performance results.

  2. Joint High Speed Sealift (JHSS) Baseline Shaft & Strut (BSS) Model 5653-3: Series 2, Propeller Disk LDV Wake Survey; and Series 3, Stock Propeller Powering and Stern Flap Evaluation Experiments

    National Research Council Canada - National Science Library

    Cusanelli, Dominic S; Chesnakas, Christopher J

    2007-01-01

    ...) and Stock Propeller Powering and Stern Flap Evaluation tests (Series 3. In order to assist in the design of a propeller for the BSS hull, the nominal wakes in the inboard and outboard starboard propeller planes were measured using LDV...

  3. PENGARUH CHILLER PENDINGIN PADA KEKERASAN PRODUK COR PROPELER ALUMUNIUM

    Directory of Open Access Journals (Sweden)

    Hera Setiawan

    2014-11-01

    Full Text Available ABSTRAK Penelitian ini merupakan pengembangkan proses pembekuan searah (unidirectional solidifications sehingga dihasilkan struktur columnar dendrite pada pengecoran alumunium propeler kapal nelayan untuk meningkatkan sifat mekanis material. Pengecoran dilakukan dengan pasir cetak (sand casting dan proses peleburan logam dilakukan pada dapur crusible dengan bahan bakar minyak. Teknik pengecoran dilakukan dengan pendinginan logam cor dengan chiller pendingin yang dialiri air dengan dorongan pompa. Pengujian spectrometer digunakan untuk mengetahui komposisi kimia material alumunium. Pengujian kekerasan digunakan metode Rockwell dengan indentor bola baja diameter 1/16 inchi dengan beban mayor 100 kg (HRB. Hasil penelitian ini menunjukkan bahwa teknik pembekuan searah dengan chiller pendingin dapat meningkatkan kekerasan material alumunium propeler sebesar 3,99% dari 60,5 HRB menjadi 62,9 HRB. Kata kunci: alumunium, propeler, chiller, kekerasan, pembekuan searah.

  4. Wind tunnel tests of stratospheric airship counter rotating propellers

    Directory of Open Access Journals (Sweden)

    Yaxi Chen

    2015-01-01

    Full Text Available Aerodynamic performance of the high-altitude propeller, especially the counter rotation effects, is experimentally studied. Influences of different configurations on a stratospheric airship, included 2-blade counter-rotating propeller (CRP, dual 2-blade single rotation propellers (SRPs and 4-blade SRP, are also indicated. This research indicates that the effect of counter rotation can greatly improve the efficiency. It shows that the CRP configuration results in a higher efficiency than the dual 2-blade SRPs configuration or 4-blade SRP configuration under the same advance ratio, and the CRP configuration also gains the highest efficiency whether under the situation of providing the same trust or absorbing the same power. It concludes that, for a stratospheric airship, the CRP configuration is better than the multiple SRPs configuration or a multi-blade SRP one.

  5. Rocket Solid Propellant Alternative Based on Ammonium Dinitramide

    Directory of Open Access Journals (Sweden)

    Grigore CICAN

    2017-03-01

    Full Text Available Due to the continuous run for a green environment the current article proposes a new type of solid propellant based on the fairly new synthesized oxidizer, ammonium dinitramide (ADN. Apart of having a higher specific impulse than the worldwide renowned oxidizer, ammonium perchlorate, ADN has the advantage, of leaving behind only nitrogen, oxygen and water after decomposing at high temperatures and therefore totally avoiding the formation of hydrogen chloride fumes. Based on the oxidizer to fuel ratios of the current formulations of the major rocket solid booster (e.g. Space Shuttle’s SRB, Ariane 5’s SRB which comprises mass variations of ammonium perchlorate oxidizer (70-75%, atomized aluminum powder (10-18% and polybutadiene binder (12-20% a new solid propellant was formulated. As previously stated, the new propellant formula and its variations use ADN as oxidizer and erythritol tetranitrate as fuel, keeping the same polybutadiene as binder.

  6. Media darling

    CERN Multimedia

    Chalmers, Matthew

    2008-01-01

    He is the media-friendly face of particle physics, appearing on countless TV and radio shows in the run-up to the opening of CERN's Large Hadron Collider. Matthew Chalmers discovers how Brian Cox finds the time to be both a physicist and a media personality. (2 pages)

  7. Instructional Media

    African Journals Online (AJOL)

    This can be summed up in a few words: Students can learn a great deal from any of the media. Under most of the conditions tested, they could learn as much as from ... Beyond physical conditions (deafness) there is little reason to expect a differential media. Scientia Militaria, South African Journal of Military Studies, Vol 13 ...

  8. Reversible self-propelled Leidenfrost droplets on ratchet surfaces

    Science.gov (United States)

    Jia, Zhi-hai; Chen, Meng-yao; Zhu, Hai-tao

    2017-02-01

    We investigate the self-propelled motion of the Leidenfrost droplets on hot surfaces with ratchet like topology. It is found that on hot ratchet surfaces with the certain geometry parameters, the droplets move in the direction towards the steep side of the teeth; as the surface temperature rises, droplets are observed to self propel to the right-angle side direction. Furthermore, there exists a temperature threshold to trigger the motion, at which the droplets do not move in either direction but stay at the stagnation state. A physical model is proposed to analyze the observation in this paper.

  9. Linear stability analysis in a solid-propellant rocket motor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.M.; Kang, K.T.; Yoon, J.K. [Agency for Defense Development, Taejon (Korea, Republic of)

    1995-10-01

    Combustion instability in solid-propellant rocket motors depends on the balance between acoustic energy gains and losses of the system. The objective of this paper is to demonstrate the capability of the program which predicts the standard longitudinal stability using acoustic modes based on linear stability analysis and T-burner test results of propellants. Commercial ANSYS 5.0A program can be used to calculate the acoustic characteristic of a rocket motor. The linear stability prediction was compared with the static firing test results of rocket motors. (author). 11 refs., 17 figs.

  10. Utilizing Solar Power Technologies for On-Orbit Propellant Production

    Science.gov (United States)

    Fikes, John C.; Howell, Joe T.; Henley, Mark W.

    2006-01-01

    The cost of access to space beyond low Earth orbit may be reduced if vehicles can refuel in orbit. The cost of access to low Earth orbit may also be reduced by launching oxygen and hydrogen propellants in the form of water. To achieve this reduction in costs of access to low Earth orbit and beyond, a propellant depot is considered that electrolyzes water in orbit, then condenses and stores cryogenic oxygen and hydrogen. Power requirements for such a depot require Solar Power Satellite technologies. A propellant depot utilizing solar power technologies is discussed in this paper. The depot will be deployed in a 400 km circular equatorial orbit. It receives tanks of water launched into a lower orbit from Earth, converts the water to liquid hydrogen and oxygen, and stores up to 500 metric tons of cryogenic propellants. This requires a power system that is comparable to a large Solar Power Satellite capable of several 100 kW of energy. Power is supplied by a pair of solar arrays mounted perpendicular to the orbital plane, which rotates once per orbit to track the Sun. The majority of the power is used to run the electrolysis system. Thermal control is maintained by body-mounted radiators; these also provide some shielding against orbital debris. The propellant stored in the depot can support transportation from low Earth orbit to geostationary Earth orbit, the Moon, LaGrange points, Mars, etc. Emphasis is placed on the Water-Ice to Cryogen propellant production facility. A very high power system is required for cracking (electrolyzing) the water and condensing and refrigerating the resulting oxygen and hydrogen. For a propellant production rate of 500 metric tons (1,100,000 pounds) per year, an average electrical power supply of 100 s of kW is required. To make the most efficient use of space solar power, electrolysis is performed only during the portion of the orbit that the Depot is in sunlight, so roughly twice this power level is needed for operations in sunlight

  11. CFD Study on Effective Wake of Conventional and Tip-modified Propellers

    DEFF Research Database (Denmark)

    Shin, K. W.; Andersen, Poul

    2016-01-01

    -propulsion tests. The effects of different Reynolds number on higher effective wake fraction of tip-modified propellers are investigated by open-water simulations with varying the propeller speed and evaluations of effective wake extracted from self-propulsion simulations on tip-modified and conventional...... propellers. Open-water simulations show that the advance ratio at the design thrust is higher at a higher Reynolds number for both propellers and the advance ratio increase is smaller for the tip-modified propeller, which results in a higher effective wake fraction. Effective wake fractions are evaluated...... by integrating velocity fields at a section 40% of the propeller radius upstream from the propeller plane in self-propulsion simulations. The difference of effective wake fraction from integrating velocity fields between tip-modified and conventional propellers is less than 1%. Based on the open-water simulation...

  12. Flexible Screen Propellant Management Device for Near Term In-Space Demonstration, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — While evaluating lunar ascent and descent stage propellant acquisition options in 2008 and 2009 for NASA GRC, IES conceived a novel, flexible screen propellant...

  13. Aerodynamic Design and Analysis of Propellers for Mini-Remotely Piloted Air Vehicles. Volume 2. Ducted Propellers

    Science.gov (United States)

    1978-05-01

    110 28t UT__n M t : X . (.4 u~..4 I 1: H 1 1I 1C . Al 0 -fUS~PD IM’ T! I I t-n!2n I 0 0 00N 0 n 0 r%~ 00 SON lca . LMNn L 0 M Nm 0nL 300 DUCTED...PROPELLERS The existing RPV’s incorporate shrouds to protect the propeller from damage and operating personnel from injury . The shrouds used are not

  14. Impact of Advanced Propeller Technology on Aircraft/Mission Characteristics of Several General Aviation Aircraft

    Science.gov (United States)

    Keiter, I. D.

    1982-01-01

    Studies of several General Aviation aircraft indicated that the application of advanced technologies to General Aviation propellers can reduce fuel consumption in future aircraft by a significant amount. Propeller blade weight reductions achieved through the use of composites, propeller efficiency and noise improvements achieved through the use of advanced concepts and improved propeller analytical design methods result in aircraft with lower operating cost, acquisition cost and gross weight.

  15. CALCULATION OF PROPELLER UAV BASED REYNOLDS NUMBER AND DEGREE OF REDUCTION

    Directory of Open Access Journals (Sweden)

    O. V. Gerasimov

    2014-01-01

    Full Text Available Presented methodology to the design and check calculations of an isolated propeller for mini-UAV based on the vortex theory of Zhukovsky. Results of the calculation of propeller mini-UAVs and their comparison with results matching propeller on a normal chart. Shows the effect of Re, as well as the degree of reduction in the aerodynamic and geometric characteristics of the propeller.

  16. Multishot diffusion-weighted SPLICE PROPELLER MRI of the abdomen.

    Science.gov (United States)

    Deng, Jie; Omary, Reed A; Larson, Andrew C

    2008-05-01

    Multishot FSE (fast spin echo)-based diffusion-weighted (DW)-PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction) MRI offers the potential to reduce susceptibility artifacts associated with single-shot DW-EPI (echo-planar imaging) approaches. However, DW-PROPELLER in the abdomen is challenging due to the large field-of-view and respiratory motion during DW preparation. Incoherent signal phase due to motion will violate the Carr-Purcell-Meiboom-Gill (CPMG) conditions, leading to destructive interference between spin echo and stimulated echo signals and consequent signal cancellation. The SPLICE (split-echo acquisition of FSE signals) technique can mitigate non-CPMG artifacts in FSE-based sequences. For SPLICE, spin echo and stimulated echo are separated by using imbalanced readout gradients and extended acquisition window. Two signal families each with coherent phase properties are acquired at different intervals within the readout window. Separate reconstruction of these two signal families can avoid destructive phase interference. Phantom studies were performed to validate signal phase properties with different initial magnetization phases. This study evaluated the feasibility of combining SPLICE and PROPELLER for DW imaging of the abdomen. It is demonstrated that DW-SPLICE-PROPELLER can effectively mitigate non-CPMG artifacts and improve DW image quality and apparent diffusion coefficient (ADC) map homogeneity. (c) 2008 Wiley-Liss, Inc.

  17. Prediction of tip vortex cavitation for ship propellers

    NARCIS (Netherlands)

    Oprea, A.I.

    2013-01-01

    An open propeller is the conventional device providing thrust for ships. Due to its working principles, regions with low pressure are formed on its blades specifically at the leading edge and in the tip region. If this pressure is becoming lower than the vapor pressure, the cavitation phenomenon is

  18. Distal driving of molar by smart distal-propeller appliance

    Directory of Open Access Journals (Sweden)

    U H Vijayashree

    2018-01-01

    Full Text Available In recent years, maxillary molar distalization with noncompliance mechanics has been an increasingly popular method for the resolution of Class II malocclusion. This communication describes one particular molar distalizing appliance, the Smart distal-propeller appliance which is simple, inexpensive, easily fabricated that can be used for unilateral or bilateral molar distalization.

  19. 78 FR 43838 - Airworthiness Directives; Hamilton Sundstrand Corporation Propellers

    Science.gov (United States)

    2013-07-22

    ... strength holding the magnets to the motor housing. The test results did not substantiate the initial... Corporation auxiliary pumps and motors (auxiliary feathering pumps). The proposed action would have required... series propellers using certain Hamilton Sundstrand Corporation auxiliary pumps and motors (auxiliary...

  20. Deflection Measurements on Propeller 5503 in Ahead and Crashback

    Science.gov (United States)

    2016-10-01

    Reynolds Number RPM... Reynolds Number (Rn) 33.67*10-5 33.67*10-5 NSWCCD-80-TR-2016/029 2 Figure 1. Propeller 5503 in LCC test section. Description of Facility...Large Cavitation Channel (LCC) The William B. Morgan Large Cavitation Channel is located in Memphis, Tennessee. It is the world’s largest high-speed

  1. Propeller Flap for Complex Distal Leg Reconstruction: A Versatile ...

    African Journals Online (AJOL)

    Reverse sural artery fasciocutaneous flap has become a workhorse for the reconstruction of distal leg soft tissue defects. When its use is not feasible, perforator‑based propeller flap offers a better, easier, faster, and cheaper alternative to free flap. We present our experience with two men both aged 34 years who sustained ...

  2. 78 FR 4038 - Critical Parts for Airplane Propellers

    Science.gov (United States)

    2013-01-18

    ... because it updates the existing regulations for airplane propellers. I. Overview of Final Rule Part 35.... General Overview of Comments The FAA received three comments. One was from a repair station, Sensenich...,555.60 per respondent which will occur on the effective date of the rule. The total cost for the three...

  3. Wear and Friction in a Controllable Pitch Propeller

    NARCIS (Netherlands)

    Godjevac, M.

    2010-01-01

    The author is a naval architect and this book is his PhD thesis. In this research the author focuses on friction in a controllable pitch propeller (CPP), formation of wear in a CPP system, and their mutual dependence. Instead of going deeply only in tribology aspects, the author tries to get an

  4. Numerical analysis for cavitation flow of marine propeller

    Science.gov (United States)

    Tauviqirrahman, Mohammad; Muchammad, Ismail, Rifky; Jamari, J.

    2015-12-01

    Concerning the environmental issue and the increase of fuel price, optimizing the fuel consumption has been recently an important subject in all industries. In marine industries one of the ways to decrease the energy consumption was by reducing the presence of cavitation on marine propeller blades. This will give a higher propulsive efficiency. This paper provides an investigation into the influence of the cavitation on a hydrodynamic performance around the propeller based on numerical method. Hydrofoil representing the blade form of propeller was of particular of interest. Two types of cavitation model were investigated with respect to the accuracy of the result and the effectiveness of the method. The results include the hydrodynamic characteristics of cavitation phenomenon like lift/drag variation with respect to the cavity extent. It was found that a high accuracy and low computational time is achieved when the cavitation model of Zwart-Gerber-Belamri is used. The interesting outcome of this study is that the results can be used as a good evaluation tool for high marine propeller performance.

  5. PIV-based load determination in aircraft propellers

    NARCIS (Netherlands)

    Ragni, D.

    2012-01-01

    The thesis describes the application of particle image velocimetry (PIV) to study the aerodynamic loads of airfoils and aircraft propellers. The experimental work focuses on the development of a measurement procedure to infer the pressure of the flow field from the velocity distribution obtained by

  6. Dynamic Model for Thrust Generation of Marine Propellers

    DEFF Research Database (Denmark)

    Blanke, Mogens; Lindegaard, Karl-Petter; Fossen, Thor I.

    2000-01-01

    Mathematical models of propeller thrust and torque are traditionally based on steady state thrust and torque characteristics obtained in model basin or cavitation tunnel tests. Experimental results showed that these quasi steady state models do not accurately describe the transient phenomena in a...

  7. Intuitive control of self-propelled microjets with haptic feedback

    NARCIS (Netherlands)

    Pacchierotti, Claudio; Magdanz, V.; Medina-Sanchez, M.; Schmidt, O.G.; Prattichizzo, D.; Misra, Sarthak

    2015-01-01

    Self-propelled microrobots have recently shown promising results in several scenarios at the microscale, such as targeted drug delivery and micromanipulation of cells. However, none of the steering systems available in the literature enable humans to intuitively and effectively control these

  8. Transportation of Nanoscale Cargoes by Myosin Propelled Actin Filaments

    NARCIS (Netherlands)

    Persson, Malin; Gullberg, Maria; Tolf, Conny; Lindberg, A. Michael; Mansson, Alf; Kocer, Armagan

    2013-01-01

    Myosin II propelled actin filaments move ten times faster than kinesin driven microtubules and are thus attractive candidates as cargo-transporting shuttles in motor driven lab-on-a-chip devices. In addition, actomyosin-based transportation of nanoparticles is useful in various fundamental studies.

  9. Weight savings in aerospace vehicles through propellant scavenging

    Science.gov (United States)

    Schneider, Steven J.; Reed, Brian D.

    1988-05-01

    Vehicle payload benefits of scavenging hydrogen and oxygen propellants are addressed. The approach used is to select a vehicle and a mission and then select a scavenging system for detailed weight analysis. The Shuttle 2 vehicle on a Space Station rendezvous mission was chosen for study. The propellant scavenging system scavenges liquid hydrogen and liquid oxygen from the launch propulsion tankage during orbital maneuvers and stores them in well insulated liquid accumulators for use in a cryogenic auxiliary propulsion system. The fraction of auxiliary propulsion propellant which may be scavenged for propulsive purposes is estimated to be 45.1 percent. The auxiliary propulsion subsystem dry mass, including the proposed scavenging system, an additional 20 percent for secondary structure, an additional 5 percent for electrical service, a 10 percent weight growth margin, and 15.4 percent propellant reserves and residuals is estimated to be 6331 kg. This study shows that the fraction of the on-orbit vehicle mass required by the auxiliary propulsion system of this Shuttle 2 vehicle using this technology is estimated to be 12.0 percent compared to 19.9 percent for a vehicle with an earth-storable bipropellant system. This results in a vehicle with the capability of delivering an additional 7820 kg to the Space Station.

  10. Developments on HNF based high performance and green solid propellants

    NARCIS (Netherlands)

    Keizers, H.L.J.; Heijden, A.E.D.M. van der; Vliet, L.D. van; Welland-Veltmans, W.H.M.; Ciucci, A.

    2001-01-01

    Worldwide developments are ongoing to develop new and more energetic composite solid propellant formulations for space transportation and military applications. Since the 90's, the use of HNF as a new high performance oxidiser is being reinvestigated. Within European development programmes,

  11. Ultrasonic investigation of mechanical properties of double base rocket propellants

    NARCIS (Netherlands)

    Schroeff, J.A. van der; Boer, R.S. de

    1976-01-01

    For a series of double base rocket propellants and for poly-methylmethacrylate (PMMA) the longitudinal and transverse sound wave velocities are measured at a frequency of 0.351 MHz in t h e temperature range of −40°C to +60°C. The relations between these acoustic properties and mechanical properties

  12. CFD simulation on Kappel propeller with a hull wake field

    DEFF Research Database (Denmark)

    Shin, Keun Woo; Andersen, Poul; Møller Bering, Rasmus

    2013-01-01

    Marine propellers are designed not for the open-water operation, but for the operation behind a hull due to the inhomogeneous hull wake and thrust deduction. The adaptation for the hull wake is important for the propulsive efficiency and cavitation risk especially on single-screw ships. CFD simul...

  13. A Computational Tool for the Rapid Design and Prototyping of Propellers for Underwater Vehicles

    Science.gov (United States)

    2007-09-01

    printer. The third study reviews the complete process of the design and production of an AUV propeller. Thus, OpenPVL performs a variety of...Butterworth-Heinemann Ltd., 1994. [4] J. E. Kerwin. Hydrofoils and Propellers. Cambridge, MIT CopyTech, 2001. [5] H. Chung, “An Enhanced Propeller

  14. Experimental set-up and results of the process of co-extruded perforated gun propellants

    NARCIS (Netherlands)

    Zebregs, M.; Driel, C.A. van

    2009-01-01

    Enhancement of gun performance can be obtained by increasing the propellant loading density or the energy content of the propellant. Serious consequences of these options are difficulties with regard to ignition and to gun barrel wear. Application of co-layered propellants is a good alternative,

  15. Aerodynamic interaction effects of tip-mounted propellers installed on the horizontal tailplane

    NARCIS (Netherlands)

    van Arnhem, N.; Sinnige, T.; Stokkermans, T.C.A.; Eitelberg, G.; Veldhuis, L.L.M.

    2018-01-01

    This paper addresses the effects of propeller installation on the aerodynamic performance of a tailplane featuring tip-mounted propellers. A model of a low aspect ratio tailplane equipped with an elevator and a tip-mounted propeller was installed in a low-speed wind-tunnel. Measurements were

  16. Analysis of swirl recovery vanes for increased propulsive efficiency in tractor propeller aircraft

    NARCIS (Netherlands)

    Veldhuis, L.L.M.; Stokkermans, T.C.A.; Sinnige, T.; Eitelberg, G.

    2016-01-01

    In this paper we address a preliminary assessment of the performance effects of swirl recovery vanes (SRVs) in a installed and uninstalled tractor propeller arrangement. A numerical analysis was performed on a propeller and a propeller-wing configuration after the SRVs were optimized first in a

  17. On the use of lifting surface theory for moderately and heavily loaded ship propellers

    NARCIS (Netherlands)

    Van Gent, W.

    1977-01-01

    It is usual to subdivide the loading range of a ship propeller, in which it developes a thrust in the direction of advance, into light, moderate and heavy loadings. The division is based on the degree to which the flow is influenced by the action of the propeller. For the heavily loaded propeller no

  18. Supplier's Status for Critical Solid Propellants, Explosive, and Pyrotechnic Ingredients

    Science.gov (United States)

    Sims, B. L.; Painter, C. R.; Nauflett, G. W.; Cramer, R. J.; Mulder, E. J.

    2000-01-01

    In the early 1970's a program was initiated at the Naval Surface Warfare Center/Indian Head Division (NSWC/IHDIV) to address the well-known problems associated with availability and suppliers of critical ingredients. These critical ingredients are necessary for preparation of solid propellants and explosives manufactured by the Navy. The objective of the program was to identify primary and secondary (or back-up) vendor information for these critical ingredients, and to develop suitable alternative materials if an ingredient is unavailable. In 1992 NSWC/IHDIV funded Chemical Propulsion Information Agency (CPIA) under a Technical Area Task (TAT) to expedite the task of creating a database listing critical ingredients used to manufacture Navy propellant and explosives based on known formulation quantities. Under this task CPIA provided employees that were 100 percent dedicated to the task of obtaining critical ingredient suppliers information, selecting the software and designing the interface between the computer program and the database users. TAT objectives included creating the Explosive Ingredients Source Database (EISD) for Propellant, Explosive and Pyrotechnic (PEP) critical elements. The goal was to create a readily accessible database, to provide users a quick-view summary of critical ingredient supplier's information and create a centralized archive that CPIA would update and distribute. EISD funding ended in 1996. At that time, the database entries included 53 formulations and 108 critical used to manufacture Navy propellant and explosives. CPIA turned the database tasking back over to NSWC/IHDIV to maintain and distribute at their discretion. Due to significant interest in propellant/explosives critical ingredients suppliers' status, the Propellant Development and Characterization Subcommittee (PDCS) approached the JANNAF Executive committee (EC) for authorization to continue the critical ingredient database work. In 1999, JANNAF EC approved the PDCS panel

  19. The experimental characterization of particle dynamics in solid composite propellants

    Science.gov (United States)

    Moore, Joseph Elijah

    There are many parameters affecting the size and behavior of aluminum (Al) droplets on and near the burning surface of composite solid propellants. Multiple points of view are studied in the current investigation. The first is in the development of a Statistical Image Correlation Velocimeter (SICV) to analyze the velocity of exhaust particles and gases leaving the burning surface. Many of the analysis techniques used in the validation of the SICV software are then used to conduct further analysis including additional propellants. The next portion of the study looks at the effect of changing two of the formulation parameters in the propellant: the metal fuel content, and the polymer binder composition. Al/Nickel (Ni) clad particles are used as an additive to the conventional Al powder. Titanium-Boron (Ti-B) is also studied as another potential intermetallic additive. The nature of the binder is studied by examining the differences between propellants made with hydroxyl-terminated polybutadiene (HTPB) and dicyclopentadiene (DCPD) binders. Strand burns are conducted in the open atmosphere as well as in a windowed combustion vessel at pressures ranging from atmospheric to 700 psig. The burning surface linear regression rate, as well as size of the agglomerated metal fuel particles leaving the surface is measured using macro- and microscopic high speed imaging followed by video analysis using modeling tools and digital particle sizing algorithms. It is shown that the partial replacement of Al with Al/Ni clad particles decreases the average size of the agglomerated particles and increases the propellant burning rate. An optimum fraction likely exists. It is also shown that ball milling, or mechanical activation, of the Al/Ni particles leads to a further increase in the burning rate of the propellant. This is likely due to a decrease in the ignition temperature of the material after it has undergone mechanical activation. Analysis of binder-specific samples reveals that

  20. Media violence.

    Science.gov (United States)

    Willis, E; Strasburger, V C

    1998-04-01

    American media are the most violent in the world, and American society is now paying a high price in terms of real life violence. Research has confirmed that mass media violence contributes to aggressive behavior, fear, and desensitization of violence. Television, movies, music videos, computer/video games are pervasive media and represent important influences on children and adolescents. Portraying rewards and punishments and showing the consequences of violence are probably the two most essential contextual factors for viewers as they interpret the meaning of what they are viewing on television. Public health efforts have emphasized public education, media literacy campaign for children and parents, and an increased use of technology to prevent access to certain harmful medial materials.

  1. Media Bias

    OpenAIRE

    Sendhil Mullainathan; Andrei Shleifer

    2002-01-01

    There are two different types of media bias. One bias, which we refer to as ideology, reflects a news outlet's desire to affect reader opinions in a particular direction. The second bias, which we refer to as spin, reflects the outlet's attempt to simply create a memorable story. We examine competition among media outlets in the presence of these biases. Whereas competition can eliminate the effect of ideological bias, it actually exaggerates the incentive to spin stories.

  2. Community Media: Muting the Democratic Media Discourse?

    NARCIS (Netherlands)

    Carpentier, N.; Lie, R.; Servaes, J.

    2003-01-01

    Focuses on the concept of community media. Components that construct the identity of community media; Multi-theoretical approaches for analysis of community media; Definition of community media based on the concept of alternative media; Link between community media and civil society; Problems faced

  3. Structural vibration and acoustic radiation of coupled propeller-shafting and submarine hull system due to propeller forces

    Science.gov (United States)

    Qu, Yegao; Su, Jinpeng; Hua, Hongxing; Meng, Guang

    2017-08-01

    This paper investigates the structural and acoustic responses of a coupled propeller-shafting and submarine pressure hull system under different propeller force excitations. The entire system, which consists of a rigid propeller, a main shaft, two bearings and an orthogonally stiffened pressure hull, is submerged in a heavy fluid. The shaft is elastically connected to the pressure hull by a radial bearing and a thrust bearing. The theoretical model of the structural system is formulated based on a modified variational method, in which the propeller, the main shaft and the bearings are treated as a lumped mass, an elastic beam and spatially distributed spring-damper systems, respectively. The rings and stringers in the pressure hull are modeled as discrete structural elements. The acoustic field generated by the hull is calculated using a spectral Kirchhoff-Helmholtz integral formulation. A strongly coupled structure-acoustic interaction analysis is employed to achieve reasonable solutions for the coupled system. The displacement of the pressure hull and the sound pressure of the fluid are expanded in the form of a double mixed series using Fourier series and Chebyshev orthogonal polynomials, providing a flexible way for the present method to account for the individual contributions of circumferential wave modes to the vibration and acoustic responses of the pressure hull in an analytical manner. The contributions of different circumferential wave modes of the pressure hull to the structural and acoustic responses of the coupled system under axial, transversal and vertical propeller forces are investigated. Computed results are compared with those solutions obtained from the coupled finite element/boundary element method. Effects of the ring and the bearing stiffness on the acoustic responses of the coupled system are discussed.

  4. Investigation on the wake evolution of contra-rotating propeller using RANS computation and SPIV measurement

    Directory of Open Access Journals (Sweden)

    Kwang-Jun Paik

    2015-05-01

    Full Text Available The wake characteristics of Contra-Rotating Propeller (CRP were investigated using numerical simulation and flow measurement. The numerical simulation was carried out with a commercial CFD code based on a Reynolds Averaged Navier-Stokes (RANS equations solver, and the flow measurement was performed with Stereoscopic Particle Image Velocimetry (SPIV system. The simulation results were validated through the comparison with the experiment results measured around the leading edge of rudder to investigate the effect of propeller operation under the conditions without propeller, with forward propeller alone, and with both forward and aft propellers. The evolution of CRP wake was analyzed through velocity and vorticity contours on three transverse planes and one longitudinal plane based on CFD results. The trajectories of propeller tip vortex core in the cases with and without aft propeller were also compared, and larger wake contraction with CRP was confirmed.

  5. Performance Analysis Rim Driven Propeller as a Propulsor using Open Water Test

    Directory of Open Access Journals (Sweden)

    Agoes Santoso

    2017-12-01

    Full Text Available The use of duct in propeller is one of the breakthrough in the development of the propeller. Ducting not only claimed to be increasing efficiency of the propeller, but also capable to protect the propeller from impact therefore propeller lifespan is longer. From that idea then RDP is created. RDP propeller blade are designed to be fix at their housing called Rim, in the other word, the driving force came from it’s rim. On current RDP blade used is non-conventional blade. This thesis will discuss about design analysis of Kaplan Propeller Kaplan Ka-70 that modified on it’s thickness distribution. On this thesis data that is varied is motor load. Simulation using Open Water Test. The result, highest value of KT and KQ occur on 30% motor load and highest efficiency is 18,338% achieved on 260 Rpm.

  6. Nonlinear Output Feedback Control of Underwater Vehicle Propellers using Advance Speed Feedback

    DEFF Research Database (Denmark)

    Fossen, T.I.; Blanke, M.

    1999-01-01

    More accurate propeller shaft speed controllers can be designed by using nonlinear control theory. In this paper, an output feedback controller reconstructing the advance speed (speed of water going into the propeller) from vehicle speed measurements is derived. For this purpose a three-state model...... of propeller shaft speed, forward (surge) speed of the vehicle and axial inlet flow of the propeller is applied. A nonlinear observer in combination with an output feedback integral controller are derived by applying Lyapunov stability theory and exponential stability is proven. The output feedback controller...... minimizes thruster losses due to variations in propeller axial inlet flow which is a major problem when applying conventional vehicle-propeller control systems. The proposed controller is simulated for an underwater vehicle equipped with a single propeller. From the simulations it can be concluded...

  7. High-Lift Propeller System Configuration Selection for NASA's SCEPTOR Distributed Electric Propulsion Flight Demonstrator

    Science.gov (United States)

    Patterson, Michael D.; Derlaga, Joseph M.; Borer, Nicholas K.

    2016-01-01

    Although the primary function of propellers is typically to produce thrust, aircraft equipped with distributed electric propulsion (DEP) may utilize propellers whose main purpose is to act as a form of high-lift device. These \\high-lift propellers" can be placed upstream of wing such that, when the higher-velocity ow in the propellers' slipstreams interacts with the wing, the lift is increased. This technique is a main design feature of a new NASA advanced design project called Scalable Convergent Electric Propulsion Technology Operations Research (SCEPTOR). The goal of the SCEPTOR project is design, build, and y a DEP aircraft to demonstrate that such an aircraft can be much more ecient than conventional designs. This paper provides details into the high-lift propeller system con guration selection for the SCEPTOR ight demonstrator. The methods used in the high-lift propeller system conceptual design and the tradeo s considered in selecting the number of propellers are discussed.

  8. Media Training

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    With the LHC starting up soon, the world's media are again turning their attention to CERN. We're all likely to be called upon to explain what is happening at CERN to media, friends and neighbours. The seminar will be given by BBC television news journalists Liz Pike and Nadia Marchant, and will deal with the kind of questions we're likely to be confronted with through the restart period. The training is open for everybody. Make sure you arrive early enough to get a seat - there are only 200 seats in the Globe. The session will also be webcast: http://webcast.cern.ch/

  9. Liquid oxygen (LO2) propellant conditioning concept testing

    Science.gov (United States)

    Perry, Gretchen L. E.; Orth, Michael S.; Mehta, Gopal K.

    1993-01-01

    Testing of a simplified LO2 propellant conditioning concept for future expendable launch vehicles is discussed. Four different concepts are being investigated: no-bleed, low-bleed, use of a recirculation line, and He bubbling. A full-scale test article, which is a facsimile of a propellant feed duct with an attached section to simulate heat input from an LO2 turbopump, is to be tested at the Cold Flow Facility of the Marshall Space Flight Center West Test Area. Work to date includes: design and fabrication of the test article, design of the test facility and initial fabrication, development of a test matrix and test procedures, initial predictions of test output, and heat leak calibration and heat exchanger tests on the test articles.

  10. Thermal Degradation Studies of A Polyurethane Propellant Binder

    Energy Technology Data Exchange (ETDEWEB)

    Assink, R.A.; Celina, M.; Gillen, K.T.; Graham, A.C.; Minier, L.M.

    1999-06-12

    The thermal oxidative aging of a crosslinked hydroxy-terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) based polyurethane rubber, used as a polymeric binder in solid propellant grain, was investigated at temperatures from 25 C to 125 C. The changes in tensile elongation, polymer network properties and chain dynamics, mechanical hardening and density were determined with a range of techniques including modulus profiling, solvent swelling, NMR relaxation and O{sub 2} permeability measurements. We critically evaluated the Arrhenius methodology that is commonly used with a linear extrapolation of high temperature aging data using extensive data superposition and highly sensitive oxygen consumption experiments. The effects of other constituents in the propellant formulation on aging were also investigated. We conclude that crosslinking is the dominant process at higher temperatures and that the degradation involves only limited hardening in the bulk of the material. Significant curvature in the Arrhenius diagram of the oxidation rates was observed. This is similar to results for other rubber materials.

  11. Magnetic propeller effect in the spectra of young stars

    Science.gov (United States)

    Grinin, V. P.; Potravnov, I. S.; Ilyin, I. V.; Shulman, S. G.

    2015-08-01

    The origin of the blueshifted narrow absorption components in the resonance sodium doublet lines observed in the spectra of some young stars is discussed. Such components are assumed to be formed by the interaction of the circumstellar gas with the stellar magnetosphere in the magnetic propeller regime. The results of observations for the post UX Ori star RZ Psc are discussed in detail. This star shows distinctive signatures of mass outflow in the absence of any clear accretion signatures. Such a picture is quite possible in the magnetic propeller regime. Estimates show that for this regime to be realized, the star must have a surface magnetic field of ~1 kG at an accretion rate that does not exceed 10-10 M . yr-1.

  12. Longitudinal acoustic instabilities in slender solid propellant rockets : linear analysis

    OpenAIRE

    García Schafer, Juan Esteban; Liñán Martínez, Amable

    2001-01-01

    To describe the acoustic instabilities in the combustion chambers of laterally burning solid propellant rockets the interaction of the mean flow with the acoustic waves is analysed, using multiple scale techniques, for realistic cases in which the combustion chamber is slender and the nozzle area is small compared with the cross-sectional area of the chamber. Associated with the longitudinal acoustic oscillations we find vorticity and entropy waves, with a wavelength typically small compared ...

  13. Self-propelled motion in a viscous compressible fluid

    Czech Academy of Sciences Publication Activity Database

    Mácha, Václav; Nečasová, Šárka

    2016-01-01

    Roč. 146, č. 2 (2016), s. 415-433 ISSN 0308-2105 R&D Projects: GA ČR(CZ) GAP201/11/1304; GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : self-propelled motion * compressible fluid * deformable structure Subject RIV: BA - General Mathematics Impact factor: 1.158, year: 2016 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10065194&fileId=S0308210515000487

  14. Project SQUID. Liquid Propellant Rockets. Volume 2, Part 2

    Science.gov (United States)

    1947-06-30

    that its pas- jector. sage cools the wall and its evaporation upon entering 1. openings: ;J the chamber further cools the wall or takes up the g heat of...is considered undesirable. An endo- b. form of approach p~assage thermic decomposition of a propellant as it passes c. porous wall through the wall...required the develop- in thc exhaust flame itself. ment and prototyping of a liquid nitrogen evaporator 4. Variations with time of temperature and for

  15. Using PDV to Understand Damage in Rocket Motor Propellants

    Science.gov (United States)

    Tear, Gareth; Chapman, David; Ottley, Phillip; Proud, William; Gould, Peter; Cullis, Ian

    2017-06-01

    There is a continuing requirement to design and manufacture insensitive munition (IM) rocket motors for in-service use under a wide range of conditions, particularly due to shock initiation and detonation of damaged propellant spalled across the central bore of the rocket motor (XDT). High speed photography has been crucial in determining this behaviour, however attempts to model the dynamic behaviour are limited by the lack of precision particle and wave velocity data with which to validate against. In this work Photonic Doppler Velocimetery (PDV) has been combined with high speed video to give accurate point velocity and timing measurements of the rear surface of a propellant block impacted by a fragment travelling upto 1.4 km s-1. By combining traditional high speed video with PDV through a dichroic mirror, the point of velocity measurement within the debris cloud has been determined. This demonstrates a new capability to characterise the damage behaviour of a double base rocket motor propellant and hence validate the damage and fragmentation algorithms used in the numerical simulations.

  16. Perforator propeller flaps for sacral and ischial soft tissue reconstruction

    Directory of Open Access Journals (Sweden)

    Korambayil Pradeoth

    2010-01-01

    Full Text Available The perforator-based flaps in the sacral and ischial region is designed according to the localization of perforators that penetrate the gluteus maximus muscle, reach the intra-fascial and supra-fascial planes with the overlying skin forming a rich vascular plexus. The perforator-based flaps described in this article are highly vascularized, have minimal donor site morbidity, and do not require the sacrifice of the gluteus maximus muscle. In a period between April 2008 and March 2009, six patients with sacral pressure sore were reconstructed with propeller flap method based on superior gluteal and parasacral artery perforators. One flap loss was noted. Three cases of ischial pressure sore were reconstructed with longitudinal propeller flap cover, based on inferior gluteal artery perforator. One flap suffered wound infection and dehiscence. Two cases of pilonidal sinus were reconstructed with propeller flap based on parasacral perforators. Both the flaps survived without any complications. Donor sites were closed primarily. In the light of this, they can be considered among the first surgical choices to re-surface soft tissue defects of the sacral and ischial regions. In the series of 11 patients, two patients (18% suffered complications.

  17. Streaming Media

    Science.gov (United States)

    Pulley, John

    2009-01-01

    At a time when the evolutionary pace of new media resembles the real-time mutation of certain microorganisms, the age-old question of how best to connect with constituents can seem impossibly complex--even for an elite institution plugged into the motherboard of Silicon Valley. Identifying the most effective vehicle for reaching a particular…

  18. Otitis media

    NARCIS (Netherlands)

    Rovers, MM; Schilder, AGM; Zielhuis, GA; Rosenfeld, RM

    2004-01-01

    Otitis media (OM) continues to be one of the most common childhood infections and is a major cause of morbidity in children. The pathogenesis of OM is multifactorial, involving the adaptive and native immune system, Eustachian-tube dysfunction, viral and bacterial load, and genetic and environmental

  19. Otitis media

    African Journals Online (AJOL)

    Infectious diseases pose quite different challenges to those who seek to apply evidence~based guidelines, as they do ... because AOM is a disease that remits ..... Schwartz B. Otitis media — principles of judicious use of antimicrobial agents. Pediatrics 1998;. 101: 165-171. Gross PA, Puj at D. Implementing practice.

  20. Social Media

    Science.gov (United States)

    2010-05-01

    Digital Marketing and Ecommerce Professionals. 29 January 2010. 20 May 2010. <http://econsultancy.com/blog/5324-20+-mind-blowing-social- media...Statistics Revisited.” Econsultancy | Community of Digital Marketing and Ecommerce Professionals. 29 Jan. 2010. 20 May 2010. <http://econsultancy.com/blog

  1. Self-propelled micromotors based on Au-mesoporous silica nanorods

    Science.gov (United States)

    Wang, Ying-Shuai; Xia, Hong; Lv, Chao; Wang, Lei; Dong, Wen-Fei; Feng, Jing; Sun, Hong-Bo

    2015-07-01

    Here, a chemical powered micromotor from the assembly of Au-SiO2 nanorods is presented. This new micromotor can be propelled efficiently by hydrogen bubbles generated from a hydrolysis reaction of aqueous NaBH4 and KBH4 and by oxygen bubbles produced by decomposition of H2O2. The monodisperse Au nanoparticles in mesoporous silica particles could catalyze the decomposition of two different kinds of fuels and produce bubbles. High speeds of 80 μm s-1 and recycles of more than 30 times are achieved in both NaBH4 and H2O2 media. Locomotion and rolling forms of movement were found. The locomotion forms can be obtained in a larger proportion by patterning the Au-SiO2 nanorods and a PDMS membrane. These micromotors that use multiple fuel sources to power them offer a broader scope of preparation and show considerable promise for diverse applications of nanomotors in different chemical environments.Here, a chemical powered micromotor from the assembly of Au-SiO2 nanorods is presented. This new micromotor can be propelled efficiently by hydrogen bubbles generated from a hydrolysis reaction of aqueous NaBH4 and KBH4 and by oxygen bubbles produced by decomposition of H2O2. The monodisperse Au nanoparticles in mesoporous silica particles could catalyze the decomposition of two different kinds of fuels and produce bubbles. High speeds of 80 μm s-1 and recycles of more than 30 times are achieved in both NaBH4 and H2O2 media. Locomotion and rolling forms of movement were found. The locomotion forms can be obtained in a larger proportion by patterning the Au-SiO2 nanorods and a PDMS membrane. These micromotors that use multiple fuel sources to power them offer a broader scope of preparation and show considerable promise for diverse applications of nanomotors in different chemical environments. Electronic supplementary information (ESI) available: More electronic microscopy graphs, UV-Vis spectra and N2 adsorption isotherms. See DOI: 10.1039/c5nr02545a

  2. 76 FR 61558 - Airworthiness Directives; Dowty Propellers Type R212/4-30-4/22 and R251/4-30-4/49 Propeller...

    Science.gov (United States)

    2011-10-05

    ... Airworthiness Directives; Dowty Propellers Type R212/4-30-4/22 and R251/4-30-4/49 Propeller Assemblies AGENCY... 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety...--AIRWORTHINESS DIRECTIVES 0 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S...

  3. 76 FR 27281 - Airworthiness Directives; Dowty Propellers Type R212/4-30-4/22 and R251/4-30-4/49 Propeller...

    Science.gov (United States)

    2011-05-11

    ... Airworthiness Directives; Dowty Propellers Type R212/4-30-4/22 and R251/4-30-4/49 Propeller Assemblies AGENCY... Rulemaking Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety... authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. Sec...

  4. 14 CFR Appendix G to Part 36 - Takeoff Noise Requirements for Propeller-Driven Small Airplane and Propeller-Driven, Commuter...

    Science.gov (United States)

    2010-01-01

    ... December 22, 1988 G Appendix G to Part 36 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT.... G Appendix G to Part 36—Takeoff Noise Requirements for Propeller-Driven Small Airplane and Propeller... A of this part. (g) A windscreen must be employed with the microphone during all measurements of...

  5. INFLUENCE OF BLADE AND PROFILE CHARACTERISTICS ON HYDRODYNAMIC EFFICIENCY OF MARINE PROPELLERS

    Directory of Open Access Journals (Sweden)

    Y. M. Korol

    2017-08-01

    Full Text Available Purpose.The study involves: 1 formation of 3D propeller models under study; 2 studying of the effect of profiling the blade of the propeller on its hydrodynamic characteristics; 3 development of a methodology for specifying optimal project parameters for modeling the operation of a propeller in free water, which in the future could be recommended when simulating similar tasks in the CFD package Flow Vision. Methodology. The technology of design of propellers of new series was developed. For the first time, the project methodology was proposed in the CFD package Flow Vision for studying the operation of a propeller in free water. Findings. On the example of solving a practical problem for studying the influence of blade profiling on the efficiency of a propeller, the expediency of developing the proposed methodology for setting a propeller design in the CFD package Flow Vision is justified. The using of this technique makes it possible to obtain reliable values of the propeller hydrodynamic characteristics for constructing its action curves, and also to reduce the estimated time. This approach makes it possible to optimize the process of designing propellers. Originality. Through numerous experiments and based on the analysis of the obtained results, it was found that the profiling of the propeller mainly affects its hydrodynamic characteristics. The choice and calculation of the propeller for the projected vessel occurs in the early stages of design. Therefore, the rationale for choosing one or another geometry of the marine propeller is a topical task. A method for specifying project parameters for conducting numerical experiments in studying the operation of propellers in free water was proposed and justified. Thus, it is possible to design not only the serial screws, but also the new series propellers, minimizing the costs of carrying out the research along with the reliability of the resulting calculation results. Practical value. Authors

  6. Analysis Effect of Duct Length– Nozzle Diameter Ratio and Tip Clearance Variation on the Performance of K-Series Propeller

    Directory of Open Access Journals (Sweden)

    Irfan Syarif Arief

    2017-12-01

    Full Text Available One type of ship propeller is a ducted propeller. Ducted propellers are propellers with sheath or duct that can increase thrust on the propeller and  useful for directing the flow of water that will pass through the Propeller. In addition to improving thrust, ducted propellers can also increase torque compared with no duct. The basic theory of momentum for this ducted propeller operation has been used by Horn (1940. In order for the efficiency of the thrust to be of good value, the volume of water passing through the propeller should be as large as possible, with the smallest possible flow velocity. The most important components of ducted propeller are Ld / D and tip clearance. Ld / D is a coefficient comparison between the length of the casing / duct and the diameter of the duct, while the tip clearance is the distance between the tip of the propeller with an inner diameter of the duct. Both components are discussed in this study. The purpose of this research is to know the performance of propeller after given variation on Ld / D and tip clearance. The method used for propeller analysis is Computational Fluid Dynamic (CFD. Based on simulation result, the most optimal propeller performance is ducted propeller with Ld / D = 0.5 and tip clearance 40 mm

  7. Otitis media with effusion

    Science.gov (United States)

    OME; Secretory otitis media; Serous otitis media; Silent otitis media; Silent ear infection; Glue ear ... Kerschner JE, Preciado D. Otitis media. In: Kliegman RM, Stanton BF, St. ... of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016: ...

  8. Effect of ambient vibration on solid rocket motor grain and propellant/liner bonding interface

    Science.gov (United States)

    Cao, Yijun; Huang, Weidong; Li, Jinfei

    2017-05-01

    In order to study the condition of structural integrity in the process of the solid propellant motor launching and transporting, the stress and strain field analysis were studied on a certain type of solid propellant motor. the vibration acceleration on the solid propellant motors' transport process were monitored, then the original vibration data was eliminated the noise and the trend term efficiently, finally the characteristic frequency of vibration was got to the finite element analysis. Experiment and simulation results show that the monitored solid propellant motor mainly bear 0.2 HZ and 15 HZ low frequency vibration in the process of transportation; Under the low frequency vibration loading, solid propellant motor grain stress concentration position is respectively below the head and tail of the propellant/liner bonding surface and the grain roots.

  9. Optimization of energy saving device combined with a propeller using real-coded genetic algorithm

    Directory of Open Access Journals (Sweden)

    Ryu Tomohiro

    2014-06-01

    Full Text Available This paper presents a numerical optimization method to improve the performance of the propeller with Turbo-Ring using real-coded genetic algorithm. In the presented method, Unimodal Normal Distribution Crossover (UNDX and Minimal Generation Gap (MGG model are used as crossover operator and generation-alternation model, respectively. Propeller characteristics are evaluated by a simple surface panel method “SQCM” in the optimization process. Blade sections of the original Turbo-Ring and propeller are replaced by the NACA66 a = 0.8 section. However, original chord, skew, rake and maximum blade thickness distributions in the radial direction are unchanged. Pitch and maximum camber distributions in the radial direction are selected as the design variables. Optimization is conducted to maximize the efficiency of the propeller with Turbo-Ring. The experimental result shows that the efficiency of the optimized propeller with Turbo-Ring is higher than that of the original propeller with Turbo-Ring.

  10. Analysis of W. F. Durand's and E. P. Lesley's propeller tests

    Science.gov (United States)

    Munk, Max M

    1924-01-01

    This report is a critical study of the results of propeller model tests with the view of obtaining a clear insight into the mechanism of the propeller action and of examining the soundness of the physical explanation generally given. The nominal slip-stream velocity is plotted against the propeller tip velocity, both measured by the velocity of flight as a unit. Within the range corresponding to conditions of flight, the curve thus obtained is a straight line. Its inclination depends chiefly on the effective blade width, its position on the effective pitch. These two quantities can therefore be determined from the result of each propeller test. Both can easily be estimated therefrom for new propellers of similar type. Thus, a simple method for the computation of propellers suggests itself.

  11. Media matters.

    Science.gov (United States)

    Martinez, L M

    1995-01-01

    The impact of the mass media on woman's status was addressed at two 1995 conferences: the Fourth World Conference on Women, held in Beijing, China, and the Congress of the World Association for Christian Communication, held in Puebla, Mexico. The globalization process facilitated by the mass media has served to increase the power of patriarchy, with no advantages to the cause of women's rights. Coverage of popular movements has been suppressed out of deference to male-controlled governments. Coverage of the Beijing Conference highlighted celebrities and personal stories, to the exclusion of the economic and political issues under debate. Television has commodified women, reinforcing their oppression. On the other hand, the alternative media, which tend to be decentralized, democratic, low-cost, and low in technology, are presenting women as subjects rather than objects and deconstructing gender stereotypes. Of concern, however, is the tendency of computer technology to widen the gap between social classes and developed and developing countries. Women must use information networks to disseminate information on women's rights and strengthen the links between women throughout the world.

  12. Media Education Initiatives by Media Organizations: The Uses of Media Literacy in Hong Kong Media

    Science.gov (United States)

    Chu, Donna; Lee, Alice Y. L.

    2014-01-01

    As more media organizations have engaged in media education, this paper investigates the goals and practices of these activities. This article coins media education initiatives by media organizations with the term "media-organization media literac"y (MOML). Four MOML projects in Hong Kong were selected for examination. Built on critical…

  13. Detonation of porous, high-HMX, nitroglycerine containing propellant by low-level shock

    Energy Technology Data Exchange (ETDEWEB)

    Green, L.G.; Chambers, E.S.; Lee, E.L.

    1982-04-01

    The sympathetic detonation throw distances to impact damaged propellant were measured. Reflected pressures at the threshold distances are about the same as pressures generated in piston compaction experiments on porous propellant at threshold piston velocities. Run distance to detonation experiments done on porous propellant using a steel impactor represent a final state from which run up to detonation occurs in both piston compaction experiments and in classical DDT experiments, which are seen as combustion driven mechanical compactions.

  14. Detonation of porous, high HMX, nitroglycerine containing propellant by low level shock

    Energy Technology Data Exchange (ETDEWEB)

    Green, L.G.; Chambers, E.S.; Lee, E.L.; Brown, B.

    1982-01-01

    We have measured sympathetic detonation throw distances to impact damaged propellant. Reflected pressures at the threshold distances are about the same as pressures generated in piston compaction experiments on porous propellant at threshold piston velocities. Run distance to detonation experiments done on porous propellant using a steel impactor represent a final state from which run up to detonation occurs in both piston compaction experiments and in classical DDT experiments, which are seen as combustion driven mechanical compactions.

  15. A numerical study of scale effects on performance of a tractor type podded propeller

    Directory of Open Access Journals (Sweden)

    Choi Jung-Kyu

    2014-06-01

    Full Text Available In this study, the scale effect on the performance of the podded propeller of tractor type is investigated. Turbulent flow computations are carried out for Reynolds numbers increasing progressively from model scale to full scale using the CFD analysis. The result of the flow calculation for model scale Reynolds numbers agrees well with that of the experiment of a large cavitation tunnel. The existing numerical analysis indicates that the performance of the podded propeller blades is mainly influenced by the advance coefficient and relatively little by the Reynolds number. However, the drag of pod housing with propeller in operation is different from that of pod housing without propeller due to the acceleration and swirl of propeller slipstream which is altered by propeller loading as well as the pressure recovery and friction according to Reynolds number, which suggests that the pod housing drag under the condition of propeller in operation is the key factor of the scale effect on the performance between model and full scale podded propellers. The so called ‘drag ratio’, which is the ratio of pod housing drag to total thrust of podded propeller, increases as the advance coefficient increases due to accelerated flow in the slipstream of the podded propeller. However, the increasing rate of the drag ratio reduces continuously as the Reynolds number increases from model to full scale progressively. The contribution of hydrodynamic forces, which acts on the parts composed of the pod housing with propeller operating in various loading conditions, to the thrust and the torque of the total propeller unit are presented for a range of Reynolds numbers from model to full scales.

  16. Studies on Decomposition and Combustion Mechanism of Solid Fuel Rich Propellants

    Science.gov (United States)

    2010-08-30

    metal hydrides , metal borides and metal alloys has also been recommended to increase heat content of FRPs. Further, ultrafine Zr powder ignites very...added in instalments to double based propellant matrix. Mixing was carried out for 45 min under vacuum at 25 C. Propellant was cast in an aluminium ...combustion efficiency of aluminized propellants with high metal contents can be attributed to the fact that aluminium oxide serves as an effective barrier

  17. Experimental study on flow-induced vibration of propeller blades under non-uniform inflow

    Directory of Open Access Journals (Sweden)

    LI Jing

    2017-12-01

    Full Text Available [Objectives] This article presents an experimental study of the flow-induced vibration of propeller blades under periodic inflow, and the dependence of the response on its modes.[Methods] Two seven-bladed highly skewed model propellers of identical proportions but different material are operated in four-cycle and six-cycle inflows to produce a blade vibratory strain response. Two kinds of wire mesh wake screens located 400 mm upstream of the propeller plane are used to generate the four-cycle and six-cycle inflows. A laser Doppler velocimetry system located 100 mm downstream of the wake screen plane is used to measure the axial velocity distributions produced by the wake screens. Strain gauges are attached to the propeller blades at different positions. The data from the strain gauges quantifies the excitation frequencies induced by the wake screens. It is shown that the response will reach peak axial propeller frequency, four times axial propeller frequency and six times axial propeller frequency under uniform inflow, four-cycle inflow and six-cycle inflow respectively.[Results] The effect of resonance on the vibratory strain response is revealed. When six times axial propeller frequency induced by six-cycle inflow coincides with the natural frequency of a flexible propeller, the response of the propeller is at its greatest.[Conclusions] This research reveals that when designing a propeller, it is not sufficient to only focus on its hydrodynamic properties; the effects of the modes of the propeller should also be considered.

  18. Performance Analysis and Investigation of the Slipstream Flow of Podded Propellers

    OpenAIRE

    ARIKAN, Yasemin; DOĞRUL, Ali; ÇELİK, Fahri

    2012-01-01

    Especially high speed craft (HSC) and vessels with large propellers have unfavourable effects on the marine environment. These effects are mostly observed on other vessels and on the marine life. The most important sources of these negative effects caused by ships are the propeller slipstream fl ow and the ship wake. Marine propellers in particular can create a large effect area by accelerating the fl ow behind the ship, so they can cause erosion on coastal structures and on the sea bed wh...

  19. Combustion Chamber Fluid Dynamics and Hypergolic Gel Propellant Chemistry Simulations for Selectable Thrust Rocket Engines

    National Research Council Canada - National Science Library

    Nusca, Michael J; Chen, Chiung-Chu; McQuaid, Michael J

    2007-01-01

    .... Computational fluid dynamics is employed to model the chemically reacting flow within a system's combustion chamber, and computational chemistry is employed to characterize propellant physical and reactive properties...

  20. Application of Model Based Prognostics to Pneumatic Valves in a Cryogenic Propellant Loading Testbed

    Data.gov (United States)

    National Aeronautics and Space Administration — Pneumatic-actuated valves are critical components in many applications, including cryogenic propellant loading for space operations. For these components, failures...

  1. PENGARUH PENGGUNAAN ENERGY SAVING DEVICE PADA PROPELLER B4 55 DENGAN METODE CFD

    Directory of Open Access Journals (Sweden)

    Andi Trimulyono

    2013-10-01

    Full Text Available Tingginya harga bahan bakar semakin mendorong pelaku industri khususnya pemilik kapal melakukan penghematan konsumsi bahan bakar dan cara yang cukup efektif untuk mengurangi konsumsi bahan bakar tersebut adalah dengan menambah instalasi alat yang disebut Energy Saving Device (ESD pada propeller dengan tujuan meningkatkan efisiensi propulsi.   Beberapa desain  ESD propeller yang telah dikembangkan yakni Ducted Propellers (Kort Nozzel propeller, dan Propeller Boss Cap Fins (PBCF. Perbedaan jenis Energy Saving Device (ESD mengindikasikan perubahan gaya torque dan thrust yang berbeda sehingga penulis disini ingin menganalisa pengaruh instalasi Energy Saving Device (ESD  pada propeller terhadap torque dan thrust yang dihasilkan sehingga dapat diketahui jenis ESD dengan performa paling optimal dengan bantuan paket program CAD (Computer Aided Design serta CFD (Computational Fluid Dynamics. Hasil analisa dengan menggunakan RANS software CFD menunjukkan akibat penambahan instalasi Energy Saving Device (ESD  pada propeller, terjadi perubahan bentuk aliran fluida, yang berpengaruh pula terhadap nilai thrust dan torque yang dihasilkan. Gaya thrust yang terjadi pada pada PBCF Propeller adalah sebesar 8.70E+05 N, dengan Torque 7.18E+05, sedangkan thrust pada Nozzle Propeller adalah sebesar 1.18E+06 dengan Torque 9.86E+05

  2. Development and Full-Scale Evaluation of a New Marine Propeller Type

    DEFF Research Database (Denmark)

    Andersen, Poul; Friesch, J.; Kappel, J.

    2004-01-01

    The KAPPEL propeller has blades curved towards the suction side at the tips. A similar application of non-planar lifting surfaces is known from modern aircraft wings having pronounced fins or winglets at the wing tips to obtain better lift-to-drag ratios. For the propeller the task is to optimise...... designed and models of all propellers examined with respect to efficiency in open-water and behind conditions. Cavitation tests were carried out for all propellers in the HYKAT cavitation tunnel at HSVA. In full scale, for the product carrier comparative sea trials were made with the conventional...

  3. An Experimental Study on the aerodynamic and aeroacoustic performances of Maple-Seed-Inspired UAV Propellers

    Science.gov (United States)

    Hu, Hui; Ning, Zhe

    2016-11-01

    Due to the auto-rotating trait of maple seeds during falling down process, flow characteristics of rotating maple seeds have been studied by many researchers in recent years. In the present study, an experimental investigation was performed to explore maple-seed-inspired UAV propellers for improved aerodynamic and aeroacoustic performances. Inspired by the auto-rotating trait of maple seeds, the shape of a maple seed is leveraged for the planform design of UAV propellers. The aerodynamic and aeroacoustic performances of the maple-seed-inspired propellers are examined in great details, in comparison with a commercially available UAV propeller purchased on the market (i.e., a baseline propeller). During the experiments, in addition to measuring the aerodynamic forces generated by the maple-seed-inspired propellers and the baseline propeller, a high-resolution Particle Image Velocimetry (PIV) system was used to quantify the unsteady flow structures in the wakes of the propellers. The aeroacoustic characteristics of the propellers are also evaluated by leveraging an anechoic chamber available at the Aerospace Engineering Department of Iowa State University. The research work is supported by National Science Foundation under Award Numbers of OSIE-1064235.

  4. Swirl-Stabilized Injector Flow and Combustion Dynamics for Liquid Propellants at Supercritical Conditions

    National Research Council Canada - National Science Library

    Yang, Vigor

    2007-01-01

    An integrated modeling and simulation program has been conducted to substantially improve the fundamental knowledge of supercritical combustion of liquid propellants under conditions representative...

  5. Japan Explosives Society Standard. 5. Measuring method for propellant; Kayaku gakkai kikaku. 5. Puroperanto keisoku hoho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-30

    This paper states a standard measuring method for propellants as a Standard of Japan Explosives Society. A propellant is a high-energy substance used as a rocket motor propellant and as a gunpowder for guns. For its practical application, its physical and chemical properties must be identified, and ignition and combustion phenomena must be understood fully. Such characteristics are also demanded that predetermined performance is maintained even after having been stored for an extended period of time, and the material will not decompose, deteriorate, or ignite spontaneously. Also, when the propellant`s energy is discharged by a rocket motor and a gun, the propellant must burn at a predetermined velocity, and cause no abnormal ignition, vibratory combustion and erosive combustion. Physical and chemical property values of propellants vary largely with materials constituting the propellants and their mixing ratio. Property requirements also vary depending on practical use conditions. Therefore, this paper describes a measuring method required to derive basic properties of the propellants, so that data derived from the measurement may be used commonly by engineers.

  6. Critical media pedagogy - theoretical underpinning and contribution to media education

    OpenAIRE

    Valenta, Petr

    2016-01-01

    Critical media pedagogy - theoretical underpinnigs and contribution to media education Dissertation Mgr. Petr Valenta Keywords critical theory, critical media pedagogy, media literacy, critical pedagogy, media, ideology, discourse, power, symbolic power, knowledge Abstract The theoretical dissertation analyzes the traditional media education model issues, which derives from the orientation of media literacy on the dominant paradigm of media effects research in media studies. Media education t...

  7. Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

    Science.gov (United States)

    Thomas, Matthew E.; Bossard, John A.; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

    2001-01-01

    The fiber optically coupled laser ignition approach summarized is under consideration for use in igniting bi-propellant rocket thrust chambers. This laser ignition approach is based on a novel dual pulse format capable of effectively increasing laser generated plasma life times up to 1000 % over conventional laser ignition methods. In the dual-pulse format tinder consideration here an initial laser pulse is used to generate a small plasma kernel. A second laser pulse that effectively irradiates the plasma kernel follows this pulse. Energy transfer into the kernel is much more efficient because of its absorption characteristics thereby allowing the kernel to develop into a much more effective ignition source for subsequent combustion processes. In this research effort both single and dual-pulse formats were evaluated in a small testbed rocket thrust chamber. The rocket chamber was designed to evaluate several bipropellant combinations. Optical access to the chamber was provided through small sapphire windows. Test results from gaseous oxygen (GOx) and RP-1 propellants are presented here. Several variables were evaluated during the test program, including spark location, pulse timing, and relative pulse energy. These variables were evaluated in an effort to identify the conditions in which laser ignition of bi-propellants is feasible. Preliminary results and analysis indicate that this laser ignition approach may provide superior ignition performance relative to squib and torch igniters, while simultaneously eliminating some of the logistical issues associated with these systems. Further research focused on enhancing the system robustness, multiplexing, and window durability/cleaning and fiber optic enhancements is in progress.

  8. Propeller Design for Naval Auxiliary AO-177 Jumbo.

    Science.gov (United States)

    1987-09-01

    0301 .0455 .0485 .0483 .0480 .0480 .0480 .0468 0.5 . 0235 .0330 .0341 .0342 .0348 .0350 .0351 .0353 0.6 .0189 .0300 .0301 .0300 .0290 .0289 .0289 .0289...the final data might be slightly different. 73• t Table 15. Comparison of HP and Propeller/ull Interaction Coefficients Between Stock and Design...necessary to maintain proper fore/aft clearances. 3. DESIGN POINT o SHP =24,000 HP (Full Power) o RPM =100 o Full-Load Condition o Wake Survey Data: See

  9. Synthesis of unsymmetrical dimethylhydrazine oxalate from rejected liquid rocket propellant

    Science.gov (United States)

    Mu, Xiaogang; Yang, Jingjing; Zhang, Youzhi

    2018-02-01

    The rejected liquid propellant unsymmetrical dimethylhydrazine (UDMH) was converted to UDMH oxalate, which has commercial value. The UDMH oxalate structure and stability were investigated by the Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and ultraviolet-visible spectrophotometric analysis. The results indicate that UDMH oxalate has good thermal and aqueous solution stability, a melting point of 144 °C, an initial decomposition temperature of 180 °C, and a peak wavelength of UV in aqueous solution at λ = 204 nm. This disposal method of rejected UDMH is highly efficient and environmentally safe.

  10. Parametric study of propeller boss cap fins for container ships

    Directory of Open Access Journals (Sweden)

    Sang-Seop Lim

    2014-06-01

    Full Text Available The global price of oil, which is both finite and limited in quantity, has been rising steadily because of the increasing requirements for energy in both developing and developed countries. Furthermore, regulations have been strengthened across all industries to address global warming. Many studies of hull resistance, propulsion and operation of ships have been performed to reduce fuel consumption and emissions. This study examined the design parameters of the propeller boss cap fin (PBCF and hub cap for 6,000TEU container ships to improve the propulsion efficiency. The design parameters of PBCF have been selected based on the geometrical shape. Computational fluid dynamics (CFD analysis with a propeller open water (POW test was performed to check the validity of CFD analysis. The design of experiment (DOE case was selected as a full factorial design, and the experiment was analyzed by POW and CFD analysis. Analysis of variance (ANOVA was performed to determine the correlation among design parameters. Four design alternatives of PBCF were selected from the DOE. The shape of a propeller hub cap was selected as a divergent shape, and the divergent angle was determined by the DOE. Four design alternatives of PBCF were attached to the divergent hub cap, and the POW was estimated by CFD. As a result, the divergent hub cap with PBCF has a negative effect on the POW, which is induced by an increase in torque coefficient. A POW test and cavitation test were performed with a divergent hub cap with PBCF to verify the CFD result. The POW test result showed that the open water efficiency was increased approximately 2% with a divergent hub cap compared to a normal cap. The POW test result was similar to the CFD result, and the divergent hub cap with the PBCF models showed lower open water efficiency. This was attributed to an increase in the torque coefficient just like the CFD results. A cavitation test was performed using the 2 models selected. The test

  11. Thermodynamic and transport properties of cryogenic propellants and related fluids

    Science.gov (United States)

    Johnson, V. J.

    1973-01-01

    Significant advances have been made in recent years in the quality and range of thermophysical data for the cryogenic propellants, pressurants, and inertants. A review of recently completed and current data compilation projects for helium, hydrogen, argon, nitrogen, oxygen, fluorine, and methane is given together with recommended references for thermodynamic and transport property data tables for these fluids. Modern techniques in the plotting of thermodynamic charts from tabular data (or from functions such as the equation of state) have greatly improved their precision and value. A list of such charts is included.

  12. Parametric study of propeller boss cap fins for container ships

    Science.gov (United States)

    Lim, Sang-Seop; Kim, Tae-Won; Lee, Dong-Myung; Kang, Chung-Gil; Kim, Soo-Young

    2014-06-01

    The global price of oil, which is both finite and limited in quantity, has been rising steadily because of the increasing requirements for energy in both developing and developed countries. Furthermore, regulations have been strengthened across all industries to address global warming. Many studies of hull resistance, propulsion and operation of ships have been performed to reduce fuel consumption and emissions. This study examined the design parameters of the propeller boss cap fin (PBCF) and hub cap for 6,000TEU container ships to improve the propulsion efficiency. The design parameters of PBCF have been selected based on the geometrical shape. Computational fluid dynamics (CFD) analysis with a propeller open water (POW) test was performed to check the validity of CFD analysis. The design of experiment (DOE) case was selected as a full factorial design, and the experiment was analyzed by POW and CFD analysis. Analysis of variance (ANOVA) was performed to determine the correlation among design parameters. Four design alternatives of PBCF were selected from the DOE. The shape of a propeller hub cap was selected as a divergent shape, and the divergent angle was determined by the DOE. Four design alternatives of PBCF were attached to the divergent hub cap, and the POW was estimated by CFD. As a result, the divergent hub cap with PBCF has a negative effect on the POW, which is induced by an increase in torque coefficient. A POW test and cavitation test were performed with a divergent hub cap with PBCF to verify the CFD result. The POW test result showed that the open water efficiency was increased approximately 2% with a divergent hub cap compared to a normal cap. The POW test result was similar to the CFD result, and the divergent hub cap with the PBCF models showed lower open water efficiency. This was attributed to an increase in the torque coefficient just like the CFD results. A cavitation test was performed using the 2 models selected. The test result showed

  13. Transient Combustion in Granular Propellant Beds. Part I. Theoretical Modeling and Numerical Solution of Transient Combustion Processes in Mobile Granular Propellant Beds

    Science.gov (United States)

    1977-08-01

    To advice the statt-of-che- art in the combustion of granular prope..lents by forwilating a complete theoretical model describ".•j the Important...d~~+W s (-.1 1-3. Where the vector products of W , W/2 , W/ , W/ and W/ vith I arte •iVn as Wl#’. m II -VVW ,÷I&. -Wig I,÷W,4A+. j IS÷ I-P(/. W/r...beginning of the granular propel.ent bed ZL Left boumdary point - •light boundary point Grek S.2 1k (Ip Thermal diffusivity of pellucsp 1 Erosive burning

  14. The Western Way? Democracy and the Media Assistance Model

    Directory of Open Access Journals (Sweden)

    Daire Higgins

    2015-01-01

    Full Text Available International media assistance took off during a time where the ideological extremes of USA vs. USSR were set to disappear. Following the Cold War, international relations focused on democracy building, and nurturing independent media was embraced as a key part of this strategy. Fukayama called it the ‘End of History’, the fact that all other ideologies had fallen and Western style democracy was set to become the one common ideology. The US and UK led the way in media assistance, with their liberal ideas of a free press, bolstered by free market capitalism. America was the superpower, and forged the way around the globe with its beacon of democracy. Under that guiding light they would bring truth, accuracy, freedom of expression and independent reporting to the countries which had so long lived under the shadow of communism, or authoritarian media systems. This is what propelled and justified American foreign policy, and their media assistance, for many years. Much work was thus carried out in Eastern Europe and the former Soviet satellites, but many now question the impact and legacy of these projects. When the US and UK spoke of media assistance they seemed to mean ‘free market’. These days, the ‘democracy promoters’ focus has turned more to Africa and the Middle East. The ideology is apparently the same: to help establish and support democracy with a stronger and more independent media. But with Western economies, and their media systems, in crisis, the relevance of this media assistance model is questioned. This essay looks at the history of media assistance and the ongoing debate on the impact of media assistance over the long term, its motives and the new balance of power appearing in international media development.

  15. Media education and media influence on youth

    OpenAIRE

    LILÁK, Karel

    2011-01-01

    Bachelor´s work is focused on the questions of the medial education and the medias themselves. This work also investigate with the influence of the action of medias to the students of apprenticeship. The first part of the theoretical work has generally explains what is media education, what is its significance for society and for the benefit of education in school. They are given functions, types and objectives of media education and communications capabilities via the media. The second part ...

  16. Media places

    DEFF Research Database (Denmark)

    Linde, Per; Messeter, Jörn

    The impact that ubiquitous wireless network technologies and mobile phones have on our experience of the modern cityscape, has been a driving force in many research projects in recent years. The agendas differ in relation to perspectives, but it seems safe to claim that such technologies are no l......The impact that ubiquitous wireless network technologies and mobile phones have on our experience of the modern cityscape, has been a driving force in many research projects in recent years. The agendas differ in relation to perspectives, but it seems safe to claim that such technologies...... are no longer neutral layers in urban living, but rather an integrated part of the materialities of architecture and urban planning, the social dimensions of city life and emerging new cultural frameworks. Arguably, we have reached a point at which digital designs may be regarded as elements of our everyday...... of how meaning can emerge in the interplay between people, artifacts and place. This paper will present the early and ongoing work in the project “Media places”, which is part of the research platform for new media at Malmö University; MEDEA. The intention is to introduce conceptual foundations...

  17. Individual and collective dynamics of self-propelled soft particles

    Science.gov (United States)

    Tarama, M.; Itino, Y.; Menzel, A. M.; Ohta, T.

    2014-01-01

    Deformable self-propelled particles provide us with one of the most important nonlinear dissipative systems, which are related, for example, to the motion of microorganisms. It is emphasized that this is a subject of localized objects in non-equilibrium open systems. We introduce a coupled set of ordinary differential equations to study various dynamics of individual soft particles due to the nonlinear couplings between migration, spinning and deformation. By introducing interactions among the particles, the collective dynamics and its collapse are also investigated by changing the particle density and the interaction strength. We stress that assemblies of self-propelled particles also exhibit a variety of non-equilibrium localized patterns. It is our great pleasure to dedicate the present article to Professor Helmut R. Brand on the occasion of his sixtieth birthday. Professor Brand has made outstanding efforts for the scientific interaction in the field of non-linear and non-equilibrium physics between Japan and Germany for the past thirty years.

  18. Performance Gains of Propellant Management Devices for Liquid Hydrogen Depots

    Science.gov (United States)

    Hartwig, Jason W.; McQuillen, John B.; Chato, David J.

    2013-01-01

    This paper presents background, experimental design, and preliminary experimental results for the liquid hydrogen bubble point tests conducted at the Cryogenic Components Cell 7 facility at the NASA Glenn Research Center in Cleveland, Ohio. The purpose of the test series was to investigate the parameters that affect liquid acquisition device (LAD) performance in a liquid hydrogen (LH2) propellant tank, to mitigate risk in the final design of the LAD for the Cryogenic Propellant Storage and Transfer Technology Demonstration Mission, and to provide insight into optimal LAD operation for future LH2 depots. Preliminary test results show an increase in performance and screen retention over the low reference LH2 bubble point value for a 325 2300 screen in three separate ways, thus improving fundamental LH2 LAD performance. By using a finer mesh screen, operating at a colder liquid temperature, and pressurizing with a noncondensible pressurant gas, a significant increase in margin is achieved in bubble point pressure for LH2 screen channel LADs.

  19. CFD Extraction of Heat Transfer Coefficient in Cryogenic Propellant Tanks

    Science.gov (United States)

    Yang, H. Q.; West, Jeff

    2015-01-01

    Current reduced-order thermal model for cryogenic propellant tanks is based on correlations built for flat plates collected in the 1950's. The use of these correlations suffers from inaccurate geometry representation; inaccurate gravity orientation; ambiguous length scale; and lack of detailed validation. This study uses first-principles based CFD methodology to compute heat transfer from the tank wall to the cryogenic fluids and extracts and correlates the equivalent heat transfer coefficient to support reduced-order thermal model. The CFD tool was first validated against available experimental data and commonly used correlations for natural convection along a vertically heated wall. Good agreements between the present prediction and experimental data have been found for flows in laminar as well turbulent regimes. The convective heat transfer between the tank wall and cryogenic propellant, and that between the tank wall and ullage gas were then simulated. The results showed that the commonly used heat transfer correlations for either vertical or horizontal plate over-predict heat transfer rate for the cryogenic tank, in some cases by as much as one order of magnitude. A characteristic length scale has been defined that can correlate all heat transfer coefficients for different fill levels into a single curve. This curve can be used for the reduced-order heat transfer model analysis.

  20. Applicability of RANS, DES and LES in propeller flow noise

    Directory of Open Access Journals (Sweden)

    LU Li

    2017-12-01

    Full Text Available [Objectives] In order to study the applicability of different turbulence models in propeller flow noise prediction, taking the DTMB 4119 propeller as the research object, the numerical simulation method is used to calculate the frequency domain noise under the non-uniform flow field.[Methods] First, the hydrodynamic coefficient and surface pressure distribution coefficient are obtained via the RANS method and the accuracy of the flow field simulation is verified by comparing it with the experimental data. Next,the pulsating pressures obtained by RANS, DES and LES are considered as the sound source respectively, and combined with the acoustic boundary element method to predict the radiation noise.[Results] The results show that spectral noise is the main contributor to total noise; when noise on 1 BPF is predicted, the results obtained by the three methods are very similar, so we can use RANS to predict noise quickly; when noise on the high order of BPF needs to be predicted, the calculation results of LES are better.[Conclusions] In noise prediction, the appropriate turbulence simulation method can be selected according to the demand.

  1. Green Propellant Infusion Mission Program Development and Technology Maturation

    Science.gov (United States)

    McLean, Christopher H.; Deininger, William D.; Joniatis, John; Aggarwal, Pravin K.; Spores, Ronald A.; Deans, Matthew; Yim, John T.; Bury, Kristen; Martinez, Jonathan; Cardiff, Eric H.; hide

    2014-01-01

    The NASA Space Technology Mission Directorate's (STMD) Green Propellant Infusion Mission (GPIM) Technology Demonstration Mission (TDM) is comprised of a cross-cutting team of domestic spacecraft propulsion and storable green propellant technology experts. This TDM is led by Ball Aerospace & Technologies Corp. (BATC), who will use their BCP- 100 spacecraft to carry a propulsion system payload consisting of one 22 N thruster for primary divert (DeltaV) maneuvers and four 1 N thrusters for attitude control, in a flight demonstration of the AF-M315E technology. The GPIM project has technology infusion team members from all three major market sectors: Industry, NASA, and the Department of Defense (DoD). The GPIM project team includes BATC, includes Aerojet Rocketdyne (AR), Air Force Research Laboratory, Aerospace Systems Directorate, Edwards AFB (AFRL), NASA Glenn Research Center (GRC), NASA Kennedy Space Center (KSC), and NASA Goddard Space Flight Center (GSFC). STMD programmatic and technology oversight is provided by NASA Marshall Space Flight Center. The GPIM project shall fly an operational AF-M315E green propulsion subsystem on a Ball-built BCP-100 spacecraft.

  2. Development of an advanced rocket propellant handler's suit

    Science.gov (United States)

    Doerr, D. F.

    2001-01-01

    Most launch vehicles and satellites in the US inventory rely upon the use of hypergolic rocket propellants, many of which are toxic to humans. These fuels and oxidizers, such as hydrazine and nitrogen tetroxide have threshold limit values as low as 0.01 PPM. It is essential to provide space workers handling these agents whole body protection as they are universally hazardous not only to the respiratory system, but the skin as well. This paper describes a new method for powering a whole body protective garment to assure the safety of ground servicing crews. A new technology has been developed through the small business innovative research program at the Kennedy Space Center. Currently, liquid air is used in the environmental control unit (ECU) that powers the propellant handlers suit (PHE). However, liquid air exhibits problems with attitude dependence, oxygen enrichment, and difficulty with reliable quantity measurement. The new technology employs the storage of the supply air as a supercritical gas. This method of air storage overcomes all of three problems above while maintaining high density storage at relatively low vessel pressures (rights reserved.

  3. Gaussian theory for spatially distributed self-propelled particles

    Science.gov (United States)

    Seyed-Allaei, Hamid; Schimansky-Geier, Lutz; Ejtehadi, Mohammad Reza

    2016-12-01

    Obtaining a reduced description with particle and momentum flux densities outgoing from the microscopic equations of motion of the particles requires approximations. The usual method, we refer to as truncation method, is to zero Fourier modes of the orientation distribution starting from a given number. Here we propose another method to derive continuum equations for interacting self-propelled particles. The derivation is based on a Gaussian approximation (GA) of the distribution of the direction of particles. First, by means of simulation of the microscopic model, we justify that the distribution of individual directions fits well to a wrapped Gaussian distribution. Second, we numerically integrate the continuum equations derived in the GA in order to compare with results of simulations. We obtain that the global polarization in the GA exhibits a hysteresis in dependence on the noise intensity. It shows qualitatively the same behavior as we find in particles simulations. Moreover, both global polarizations agree perfectly for low noise intensities. The spatiotemporal structures of the GA are also in agreement with simulations. We conclude that the GA shows qualitative agreement for a wide range of noise intensities. In particular, for low noise intensities the agreement with simulations is better as other approximations, making the GA to an acceptable candidates of describing spatially distributed self-propelled particles.

  4. Self-propelled nanotools drilling into cells and tissues

    International Nuclear Information System (INIS)

    Sanchez, Samuel; Xi, Wang; Solovev, Alexander; Schmidt, Oliver

    2013-01-01

    We designed nanoscale tools in the form of autonomous and remotely guided catalytically and magnetically self-propelled micro- and nanotools. Asymmetrically rolled-up nanotools move in a corkscrewlike trajectory, allowing these tiny tubes to drill and embed themselves into biomaterials (fixed HeLa cells and tissues). First, we designed the smallest self-propelled nanojet engine (InGaAs/GaAs/(Cr)Pt) with diameters in the range of 280-600 nm, which move in hydrogen peroxide solutions with speeds as high as 180 μm.s -1 and perform advanced tasks such as drilling into cancer cells. Also, we demonstrated that tubular fuelfree Ti/Cr/Fe micro-drillers containing sharp tips can be applied for mechanical drilling operations of porcine liver tissue ex vivo. An external rotational magnetic field is used to remotely locate and actuate the micro-drillers in a solution with a viscosity comparable to that of biological fluids (e.g., blood). (authors)

  5. Development of a Microchannel In Situ Propellant Production System

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Kriston P.; Rassat, Scot D.; TeGrotenhuis, Ward E.

    2005-09-01

    An in situ propellant production (ISPP) plant on future Mars robotic missions can produce oxygen (O2) and methane (CH4) that can be used for propellant for the return voyage. By producing propellants from Mars atmospheric carbon dioxide (CO2) and hydrogen (H2) brought from Earth, the initial mass launched in low Earth orbit can be reduced by 20% to 45%, as compared to carrying all of the propellant for a round-trip mission to the Mars surface from Earth. Pacific Northwest National Laboratory used microchannel architecture to develop a Mars-based In Situ Propellant Production (ISPP) system. This three year research and development effort focused on process intensification and system miniaturization of three primary subsystems: a thermochemical compressor, catalytic reactors, and components for separating gas phases from liquid phases. These systems were designed based on a robotic direct return mission scenario, but can be scaled up to human flight missions by simply numbering up the microchannel devices. The thermochemical compression was developed both using absorption and adsorption. A multichannel adsorption system was designed to meet the full-scale CO2 collection requirements using temperature swing adsorption. Each stage is designed to achieve a 10x compression of CO2. A compression ratio to collect Martian atmospheric CO2 at ~0.8 kPa and compress it to at least 100 kPa can be achieved with two adsorption stages in series. A compressor stage incorporates eight thermally coupled adsorption cells at various stages in the adsorption/desorption cycle to maximize the recuperation of thermal energy and provide a nearly continuous flow of CO2 to the downstream reactors. The thermochemically compressed CO2 is then mixed with hydrogen gas and fed to two reactors: a Sabatier Reaction unit and a Reverse Water/Gas Shift unit. The microchannel architecture allows better heat control than is possible in an adiabatic system, resulting in significantly higher conversion. The

  6. JANNAF 28th Propellant Development and Characterization Subcommittee and 17th Safety and Environmental Protection Subcommittee Joint Meeting. Volume 1

    Science.gov (United States)

    Cocchiaro, James E. (Editor); Mulder, Edwin J. (Editor); Gomez-Knight, Sylvia J. (Editor)

    1999-01-01

    This volume contains 37 unclassified/unlimited-distribution technical papers that were presented at the JANNAF 28th Propellant Development & Characterization Subcommittee (PDCS) and 17th Safety & Environmental Protection Subcommittee (S&EPS) Joint Meeting, held 26-30 April 1999 at the Town & Country Hotel and the Naval Submarine Base, San Diego, California. Volume II contains 29 unclassified/limited-distribution papers that were presented at the 28th PDCS and 17th S&EPS Joint Meeting. Volume III contains a classified paper that was presented at the 28th PDCS Meeting on 27 April 1999. Topics covered in PDCS sessions include: solid propellant rheology; solid propellant surveillance and aging; propellant process engineering; new solid propellant ingredients and formulation development; reduced toxicity liquid propellants; characterization of hypergolic propellants; and solid propellant chemical analysis methods. Topics covered in S&EPS sessions include: space launch range safety; liquid propellant hazards; vapor detection methods for toxic propellant vapors and other hazardous gases; toxicity of propellants, ingredients, and propellant combustion products; personal protective equipment for toxic liquid propellants; and demilitarization/treatment of energetic material wastes.

  7. 76 FR 9495 - Feathering Propeller Systems for Light-Sport Aircraft Powered Gliders

    Science.gov (United States)

    2011-02-18

    ..., 2011. The final rule amends the definition of light-sport aircraft by removing ``auto'' from the term... Administration 14 CFR Part 1 RIN 2120-AJ81 Feathering Propeller Systems for Light-Sport Aircraft Powered Gliders... propeller operation for powered gliders that qualify as light-sport aircraft. DATES: The effective date for...

  8. Cavitation tunnel analysis of radiated sound from the resonance of a propeller tip vortex cavity

    NARCIS (Netherlands)

    Pennings, P.C.; Westerweel, J.; Van Terwisga, T.J.C.

    2016-01-01

    The goal of this study is to test the hypothesis that the resonance of a tip vortex cavity is responsible for high-amplitude broadband pressure-fluctuations, typically between 40 and 70 Hz,Hz, for a full scale propeller. This is achieved with a model propeller in a cavitation tunnel. Simultaneous

  9. Image-based magnetic control of self-propelling catalytic micro motors

    NARCIS (Netherlands)

    de Vries, Jeroen; Keuning, J.; Zondervan, L.; Misra, Sarthak; Abelmann, Leon

    2011-01-01

    This paper describes our work to magnetically steer self-propelled devices whichmove by catalysis of hydrogen peroxide. We demonstrate manipulation of paramagnetic particles with a diameter of 100μm to a given setpoint by means of magnetic field gradients, as well as self-propelled movement of

  10. Enhanced Ionization Of Propellant Through Carbon Nanotube Growth On Angled Walls

    Science.gov (United States)

    2017-06-01

    INTENTIONALLY LEFT BLANK iii Approved for public release. Distribution is unlimited. ENHANCED IONIZATION OF PROPELLANT THROUGH CARBON NANOTUBE...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release. Distribution is unlimited. ENHANCED...IONIZATION OF PROPELLANT THROUGH CARBON NANOTUBE GROWTH ON ANGLED WALLS by Alfred P. Garvey June 2017 Thesis Advisor: Dragoslav Grbovic Second

  11. A Comparative Study of Conventional and Tip-Fin Propeller Performance

    DEFF Research Database (Denmark)

    Andersen, Poul

    1997-01-01

    .The results of the model tests show higher open-water efficiency of the tip-fin propeller as well as higher over-all propulsive efficency. Depending on the method used in the full-scale extrapolation this corresponds to reduction in propulsive power of 3.7 to 4.7 per cent. Both propellers suffer from slight...

  12. Conference Proceedings on Smokeless Propellants Held in Florence, Italy on 12-13 September 1985

    Science.gov (United States)

    1986-01-01

    state burning of homogeneous propellants. Chapitre 7 de Fundamentals of Solid-Propellant Combustion, op. cit. (7) - J.F. TRUBERT Analyse deni Bas dana...Dibble T.mperature sensitivity of deflagration rates of cyclotetramethylene tetranitramine (HMX) 13th JAI AF Combustion meeting, 1976. [101 J.D. Cosgrove

  13. Numerical simulation on bearing force of propeller for machining errors in non-uniform inflow

    Directory of Open Access Journals (Sweden)

    YU Anbin

    2017-03-01

    Full Text Available In order to study the bearing force caused by the machining errors of composite material propeller in non-uniform flow, the propeller was computed by changing the machining error of the propeller in six degrees of freedom, in which the main blade translates and rotates along the coordinate axis artificially by way of the statistical method. The bearing force of a DTMB P4119 propeller with a machining error was calculated according to the SST k-ω model and sliding meshing non-uniform flow to figure out the impact of various machining errors on the propeller, enabling a fundamental rule about the impact of various machining errors on a propeller's bearing force to be formed. The results show that vertical bearing force and horizontal bearing force increase linearly, and first-order blade frequency bearing force rarely changes with the increase of machining errors in each freedom; machining errors along the directions of diameter and pitch have a great impact on the propeller shaft's frequency bearing force. Therefore, we can put forward a more refined principle about the machining accuracy of propellers.

  14. On the Stress Analysis of the Kappel Propeller using Finite Elements

    DEFF Research Database (Denmark)

    Atkinson, P.; Andersen, Poul

    2003-01-01

    The Kappel propeller design concept promotes the inclusion of a "forward facing" blade tip winglet with the objective that propeller efficiency may be improved. Design development has enabled a series of finite element investigations in order to establish how the inclusion of an unconventional bl...

  15. Influence of Propulsion Type on the Stratified Near Wake of an Axisymmetric Self-Propelled Body

    Directory of Open Access Journals (Sweden)

    Matthew C. Jones

    2018-05-01

    Full Text Available To better understand the influence of swirl on the thermally-stratified near wake of a self-propelled axisymmetric vehicle, three propulsor schemes were considered: a single propeller, contra-rotating propellers (CRP, and a zero-swirl, uniform-velocity jet. The propellers were modeled using an Actuator-Line model in an unsteady Reynolds-Averaged Navier–Stokes simulation, where the Reynolds number is R e L = 3.1 × 10 8 using the freestream velocity and body length. The authors previously showed good comparison to experimental data with this approach. Visualization of vortical structures shows the helical paths of blade-tip vortices from the single propeller as well as the complicated vortical interaction between contra-rotating blades. Comparison of instantaneous and time-averaged fields shows that temporally stationary fields emerge by half of a body length downstream. Circumferentially-averaged axial velocity profiles show similarities between the single propeller and CRP in contrast to the jet configuration. Swirl velocity of the CRP, however, was attenuated in comparison to that of the single propeller case. Mixed-patch contour maps illustrate the unique temperature distribution of each configuration as a consequence of their respective swirl profiles. Finally, kinetic and potential energy is integrated along downstream axial planes to reveal key differences between the configurations. The CRP configuration creates less potential energy by reducing swirl that would otherwise persist in the near wake of a single-propeller wake.

  16. FANS Simulation of Propeller Wash at Navy Harbors (ESTEP Project ER-201031)

    Science.gov (United States)

    2016-08-01

    TECHNICAL REPORT 2085 August 2016 FANS Simulation of Propeller Wash at Navy Harbors (ESTEP Project ER-201031) Pei-Fang Wang SSC Pacific Hamn...4 2.1 FANS Model Simulation Results for DDG 51 Ship ............................................................ 5 2.2 Disturbed Velocity...15 3.1 FANS Model Simulation Results for Tugboat with Ducted Propellers ..............................18 3.2 Disturbed Velocity Profiles

  17. Finite element modelling and model updating of small scale composite propellers

    NARCIS (Netherlands)

    Maljaars, P.J.; Kaminski, M.L.; den Besten, J.H.

    2017-01-01

    The application of composite materials in marine propellers is a relatively recent innovation. Methods have been presented to analyse the hydro-elastic behaviour of these type of propellers and in some studies these methods have been validated as well. Differences between measured and predicted

  18. CFD analysis of cloud cavitation on three tip-modified propellers with systematically varied tip geometry

    Science.gov (United States)

    Shin, K. W.; Andersen, P.

    2015-12-01

    The blade tip loading is often reduced as an effort to restrain sheet and tip vortex cavitation in the design of marine propellers. This CFD analysis demonstrates that an excessive reduction of the tip loading can cause cloud cavitation responsible for much of noise and surface erosion. Detached eddy simulations (DES) are made for cavitating flows on three tip- modified propellers, of which one is a reference propeller having an experimental result from a cavitation tunnel test with a hull model, and the other two are modified from the reference propeller by altering the blade tip loading. DES results have been validated against the experiment in terms of sheet and cloud cavitation. In DES, non-uniform hull wake is modelled by using the inlet flow and momentum sources instead of including a hull model. A 4-bladed Kappel propeller with a smooth tip bending towards the suction side is used as the reference propeller. For the reference propeller, sheet cavitation extends over a whole chord length in the hull wake peak. As the blade gets out of the wake peak, the rear part of sheet cavity is detached in a form of cloud cavitation. For the reference propeller, the tip pitch reduction from the maximum is about 35%. When decreasing the tip pitch reduction to 10%, tip vortex cavitation is formed and cloud cavitation is significantly weakened. When increasing the tip pitch reduction to 60%, sheet cavitation slightly moves to inner radii and cloud cavitation grows larger.

  19. EFFECT OF GEOMETRIC CONFIGURATIONS ON HYDRODYNAMIC PERFORMANCE ASSESSMENT OF A MARINE PROPELLER

    Directory of Open Access Journals (Sweden)

    Samir. E. Belhenniche

    2016-12-01

    Full Text Available The present paper deals with the effect of the geometric characteristics on the propeller hydrodynamic performances. Several propeller configurations are created by changing number of blades, expanded area and pitch ratios. The Reynolds-Averaged Navier-Stokes (RANS equations are solved using the commercial code FLUENT 6.3.26. The standard

  20. Calculation of marine propeller static strength based on coupled BEM/FEM

    Directory of Open Access Journals (Sweden)

    YE Liyu

    2017-10-01

    Full Text Available [Objectives] The reliability of propeller stress has a great influence on the safe navigation of a ship. To predict propeller stress quickly and accurately,[Methods] a new numerical prediction model is developed by coupling the Boundary Element Method(BEMwith the Finite Element Method (FEM. The low order BEM is used to calculate the hydrodynamic load on the blades, and the Prandtl-Schlichting plate friction resistance formula is used to calculate the viscous load. Next, the calculated hydrodynamic load and viscous correction load are transmitted to the calculation of the Finite Element as surface loads. Considering the particularity of propeller geometry, a continuous contact detection algorithm is developed; an automatic method for generating the finite element mesh is developed for the propeller blade; a code based on the FEM is compiled for predicting blade stress and deformation; the DTRC 4119 propeller model is applied to validate the reliability of the method; and mesh independence is confirmed by comparing the calculated results with different sizes and types of mesh.[Results] The results show that the calculated blade stress and displacement distribution are reliable. This method avoids the process of artificial modeling and finite element mesh generation, and has the advantages of simple program implementation and high calculation efficiency.[Conclusions] The code can be embedded into the code of theoretical and optimized propeller designs, thereby helping to ensure the strength of designed propellers and improve the efficiency of propeller design.

  1. Application of Laser Diffraction Techniques to Particle Sizing in Solid Propellant Rocket Motors

    Science.gov (United States)

    1987-12-01

    filament energized by a 12 VDC source. The propellant was bonded into the motor casing with a self-vulcanizing silicone rubber (RTV). The propellant...California 93943-5100 5. LCDR C. D. Younabr 2 992 Cobblestone Drive Orange Park, Florida 32073 6. .T .arlow Moser, USAF 2 Ston 24 Air Force Nstronautics

  2. CFD Analysis of Scale Effects on Conventional and Tip-Modified Propellers

    DEFF Research Database (Denmark)

    Shin, Keun Woo; Andersen, Poul

    2017-01-01

    Full-scale propeller performance is traditionally predictedby scaling model-scale test results, but the traditionalscaling methods do not take into account hydrodynamicdistinctions of tip-modified propellers in full-scaleperformance. An open-water CFD analysis is made onscale effects of tip...

  3. Accelerated aging of AP/HTPB propellants and the influence of various environmental aging conditions

    NARCIS (Netherlands)

    Keizers, H.L.J.

    1995-01-01

    Preliminary resuits on accelerated aging of lab-scale produced AP/HTPB propellant and propellants from dissectioned rocket motors are discussed, including aging logic, storage conditions, test techniques and resuits on mechanical, ballistic and safety testing. The mam aging effect observed was

  4. CFD analysis of cascade effects in marine propellers with trailing edge modification

    DEFF Research Database (Denmark)

    Shin, Keun Woo; Andersen, Poul

    2015-01-01

    Propeller blades are different from a single hydrofoilin isolation due to cascade effects that blades mutually affect hydrodynamic characteristics of each other in proximity. Propeller design programs based lifting-line theory and blade element momentum theory take into account cascade effect by ...

  5. Geographic Media Literacy

    Science.gov (United States)

    Lukinbeal, Chris

    2014-01-01

    While the use of media permeates geographic research and pedagogic practice, the underlying literacies that link geography and media remain uncharted. This article argues that geographic media literacy incorporates visual literacy, information technology literacy, information literacy, and media literacy. Geographic media literacy is the ability…

  6. Adolescents and media literacy.

    Science.gov (United States)

    McCannon, Robert

    2005-06-01

    In the face of media industry consolidation, fewer people control media content which makes it harder for parents and citizens to know the research about media-related issues, such as video game violence, nutrition, and sexual risk-taking. Media literacy offers a popular and potentially successful way to counter the misinformation that is spread by Big Media public relations.

  7. Measuring News Media Literacy

    Science.gov (United States)

    Maksl, Adam; Ashley, Seth; Craft, Stephanie

    2015-01-01

    News media literacy refers to the knowledge and motivations needed to identify and engage with journalism. This study measured levels of news media literacy among 500 teenagers using a new scale measure based on Potter's model of media literacy and adapted to news media specifically. The adapted model posits that news media literate individuals…

  8. High Energy, Low Temperature Gelled Bi-Propellant Formulation for Long-Duration In-Space Propulsion, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The use of gelled propellants for deep space planetary missions may enable adoption of high performance (Isp-vac>360 sec) propellant combinations that do not...

  9. Numerical Investigation of Viscous Flow Velocity Field around a Marine Cavitating Propeller

    Directory of Open Access Journals (Sweden)

    Zhifeng Zhu

    2014-11-01

    Full Text Available Velocity field around a ship cavitating propeller is investigated based on the viscous multiphase flow theory. Using a hybrid grid, the unsteady Navier-stokes (N-S and the bubble dynamics equations are solved in this paper to predict the velocity in a propeller wake and the vapor volume fraction on the back side of propeller blade for a uniform inflow. Compared with experimental results, the numerical predictions of cavitation and axial velocity coincide with the measured data. The evolution of tip vortex is shown, and the interaction between the tip vortex of the current blade and the wake of the next one occurs in the far propeller wake. The frequency of velocity signals changes from shaft rate to blade rate. The phenomena reflect the instability of propeller wake.

  10. Nonlinear output feedback control of underwater vehicle propellers using feedback form estimated axial flow velocity

    DEFF Research Database (Denmark)

    Fossen, T. I.; Blanke, Mogens

    2000-01-01

    Accurate propeller shaft speed controllers can be designed by using nonlinear control theory and feedback from the axial water velocity in the propeller disc. In this paper, an output feedback controller is derived, reconstructing the axial flow velocity from vehicle speed measurements, using...... a three-state model of propeller shaft speed, forward (surge) speed of the vehicle, and the axial flow velocity. Lyapunov stability theory is used to prove that a nonlinear observer combined with an output feedback integral controller provide exponential stability. The output feedback controller...... compensates for variations in thrust due to time variations in advance speed. This is a major problem when applying conventional vehicle-propeller control systems, The proposed controller is simulated for an underwater vehicle equipped with a single propeller. The simulations demonstrate that the axial water...

  11. Experimental investigation of atomization characteristics of swirling spray by ADN gelled propellant

    Science.gov (United States)

    Guan, Hao-Sen; Li, Guo-Xiu; Zhang, Nai-Yuan

    2018-03-01

    Due to the current global energy shortage and increasingly serious environmental issues, green propellants are attracting more attention. In particular, the ammonium dinitramide (ADN)-based monopropellant thruster is gaining world-wide attention as a green, non-polluting and high specific impulse propellant. Gel propellants combine the advantages of liquid and solid propellants, and are becoming popular in the field of spaceflight. In this paper, a swirling atomization experimental study was carried out using an ADN aqueous gel propellant under different injection pressures. A high-speed camera and a Malvern laser particle size analyzer were used to study the spray process. The flow coefficient, cone angle of swirl atomizing spray, breakup length of spray membrane, and droplet size distribution were analyzed. Furthermore, the effects of different injection pressures on the swirling atomization characteristics were studied.

  12. Boundary Element Method Applied to Added Mass Coefficient Calculation of the Skewed Marine Propellers

    Directory of Open Access Journals (Sweden)

    Yari Ehsan

    2016-04-01

    Full Text Available The paper mainly aims to study computation of added mass coefficients for marine propellers. A three-dimensional boundary element method (BEM is developed to predict the propeller added mass and moment of inertia coefficients. Actually, only few experimental data sets are available as the validation reference. Here the method is validated with experimental measurements of the B-series marine propeller. The behavior of the added mass coefficients predicted based on variation of geometric and flow parameters of the propeller is calculated and analyzed. BEM is more accurate in obtaining added mass coefficients than other fast numerical methods. All added mass coefficients are nondimensionalized by fluid density, propeller diameter, and rotational velocity. The obtained results reveal that the diameter, expanded area ratio, and thickness have dominant influence on the increase of the added mass coefficients.

  13. Partial drift volume due to a self-propelled swimmer

    Science.gov (United States)

    Chisholm, Nicholas G.; Khair, Aditya S.

    2018-01-01

    We assess the ability of a self-propelled swimmer to displace a volume of fluid that is large compared to its own volume via the mechanism of partial drift. The swimmer performs rectilinear locomotion in an incompressible, unbounded Newtonian fluid. The partial drift volume D is the volume of fluid enclosed between the initial and final profiles of an initially flat circular disk of marked fluid elements; the disk is initially aligned perpendicular to the direction of locomotion and subsequently distorted due to the passage of the swimmer, which travels a finite distance. To focus on the possibility of large-scale drift, we model the swimmer simply as a force dipole aligned with the swimming direction. At zero Reynolds number (Re =0 ), we demonstrate that D grows without limit as the radius of the marked fluid disk h is made large, indicating that a swimmer at Re =0 can generate a partial drift volume much larger than its own volume. Next, we consider a steady swimmer at small Re , which is modeled as the force-dipole solution to Oseen's equation. Here, we find that D no longer diverges with h , which is due to inertial screening of viscous forces, and is effectively proportional to the magnitude of the force dipole exerted by the swimmer. The validity of this result is extended to Re ≥O (1 ) —the realm of intermediate-Re swimmers such as copepods—by taking advantage of the fact that, in this case, the flow is also described by Oseen's equations at distances much larger than the characteristic linear dimension of the swimmer. Next, we utilize an integral momentum balance to demonstrate that our analysis for a steady inertial swimmer also holds, in a time-averaged sense, for an unsteady swimmer that does not experience a net acceleration over a stroke cycle. Finally, we use experimental data to estimate D for a few real swimmers. Interestingly, we find that D depends heavily on the kinematics of swimming, and, in certain cases, D can be significantly greater

  14. Media Literacy in Times of Media Divides

    Directory of Open Access Journals (Sweden)

    Kaja Žuran

    2013-12-01

    Full Text Available We live in a post-modern society, an information society, a society based around knowledge and participation, and above all in a media society. In a media culture where media holds a dominant position, we cannot overlook the emerging idea of a ‘media divide’ within the frame of media education, media literate individuals and the expansion of the traditional concept of media literacy. Firstly, we are in an era of technological revolution, and it is time to consider the meaning and function of media and how we experience it in our everyday life. Secondly, as a society we are subject to intense media invasion and we all need to learn how to use it to our benefit and apply a critical and autonomous perspective towards selecting media content. Otherwise the media divide between the media literate and illiterate will widen; but is there even a chance to overcome the supposed divide between those who are formally media educated and those who are not?

  15. Deconsolidation and combustion performance of thermally consolidated propellants deterred by multi-layers coating

    Directory of Open Access Journals (Sweden)

    Zheng-gang Xiao

    2014-06-01

    Full Text Available Both heating and solvent-spray methods are used to consolidate the standard grains of double-base oblate sphere propellants plasticized with triethyleneglycol dinitrate (TEGDN (TEGDN propellants to high density propellants. The obtained consolidated propellants are deterred and coated with the slow burning multi-layer coating. The maximum compaction density of deterred and coated consolidated propellants can reach up to 1.39 g/cm3. Their mechanic, deconsolidation and combustion performances are tested by the materials test machine, interrupted burning set-up and closed vessel, respectively. The static compression strength of consolidated propellants deterred by multi-layer coating increases significantly to 18 MPa, indicating that they can be applied in most circumstances of charge service. And the samples are easy to deconsolidate in the interrupted burning test. Furthermore, the closed bomb burning curves of the samples indicate a two-stage combustion phenomenon under the condition of certain thickness of coated multi-layers. After the outer deterred multi-layer coating of consolidated samples is finished burning, the inner consolidated propellants continue to burn and breakup into aggregates and grains. The high burning progressivity can be carefully obtained by the smart control of deconsolidation process and duration of consolidated propellants. The preliminary results of consolidated propellants show that a rapid deconsolidation process at higher deconsolidation pressure is presented in the dynamic vivacity curves of closed bomb test. Higher density and higher macro progressivity of consolidated propellants can be obtained by the techniques in this paper.

  16. Holograms as complex media

    Science.gov (United States)

    Caulfield, H. John

    2005-08-01

    Complex media can be grown, found in nature, or manufactured.. Holography is one way of fabricating such media. Here I review some examples of holographically manufactured complex media and speculate about some that could be made.

  17. Prostate-specific Antigen Parameters and Prostate Health Index Enhance Prostate Cancer Prediction With the In-bore 3-T Magnetic Resonance Imaging-guided Transrectal Targeted Prostate Biopsy After Negative 12-Core Biopsy.

    Science.gov (United States)

    Friedl, Alexander; Stangl, Kathrin; Bauer, Wilhelm; Kivaranovic, Danijel; Schneeweiss, Jenifer; Susani, Martin; Hruby, Stephan; Lusuardi, Lukas; Lomoschitz, Fritz; Eisenhuber-Stadler, Edith; Schima, Wolfgang; Brössner, Clemens

    2017-12-01

    To assess prostate cancer (PCa) detection and prediction by combining the in-bore magnetic resonance imaging-guided transrectal targeted prostate biopsy (MRGB) with prostate-specific antigen (PSA) parameters and the Prostate Health Index (PHI) in case of negative 12-core standard biopsy. A total of 112 men (2014-2016) underwent 3-T multiparametric magnetic resonance imaging and subsequent MRGB of Prostate Imaging-Reporting and Data System (PI-RADS) lesions 3-5. Ancillary PSA parameters (PSA ratio [%fPSA] and PSA density [PSAD]) and the PHI and PHI density (PHID) were recorded. With these parameters in combination with MRGB, PCa prediction was calculated. The most common lesions biopsied were PI-RADS 4 (66%), located in the peripheral zone (64%), in the middle (58%) and anterior (65%) sections of the prostate, and 13 mm (IQR 10-15) in size. PCa was found in 62 (55%) patients (28% Gleason score ≥7). PSAD (0.15 vs 0.21; P = .0051), %fPSA (16 vs 13; P = .0191), PHI (45 vs 69; P PI-RADS 3-5 lesions. By considering PHI and PHID, 82% and 62% of unnecessary biopsies could have been avoided, failing to detect 31% and 16% of cancers. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Propellant Flow Actuated Piezoelectric Igniter for Combustion Engines

    Science.gov (United States)

    Wollen, Mark A. (Inventor)

    2015-01-01

    A propellant flow actuated piezoelectric igniter device using one or more hammer balls retained by one or more magnets, or other retaining method, until sufficient fluid pressure is achieved to release and accelerate the hammer ball, such that it impacts a piezoelectric crystal to produce an ignition spark. Certain preferred embodiments provide a means for repetitively capturing and releasing the hammer ball after it impacts one or more piezoelectric crystals, thereby oscillating and producing multiple, repetitive ignition sparks. Furthermore, an embodiment is presented for which oscillation of the hammer ball and repetitive impact to the piezoelectric crystal is maintained without the need for a magnet or other retaining mechanism to achieve this oscillating impact process.

  19. Recent Progress in Bionic Condensate Microdrop Self-Propelling Surfaces.

    Science.gov (United States)

    Gong, Xiaojing; Gao, Xuefeng; Jiang, Lei

    2017-12-01

    Bionic condensate microdrop self-propelling (CMDSP) surfaces are attracting increased attention as novel, low-adhesivity superhydrophobic surfaces due to their value in fundamental research and technological innovation, e.g., for enhancing heat transfer, energy-effective antifreezing, and electrostatic energy harvesting. Here, the focus is on recent progress in bionic CMDSP surfaces. Metal-based CMDSP surfaces, which are the most promising in their respective fields, are highlighted for use in future applications. The selected topics are divided into four sections: biological prototypes, mechanism and construction rules, fabrication, and applications of metal-based CMDSP surfaces. Finally, the challenges and future development trends in bionic CMDSP surfaces are envisioned, especially the utilization of potential bionic inspiration in the design of more advanced CMDSP surfaces. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Rectified transport of a ring containing self-propelled particles

    Science.gov (United States)

    Huang, Xiao-Qun; Liao, Jing-Jing; Ai, Bao-Quan

    2018-02-01

    Rectified transport of a ring containing self-propelled particles is numerically investigated in a two-dimensional herringbone potential. It is found that the ring powered by active particles can be rectified in the asymmetric potential and the direction of the transport is determined by the asymmetry of the potential. The ring radius can strongly affect the transport and the role of the radius on the average velocity depends on the profile of the potential and the self-propulsion speed. There exist optimal values of the parameters (the self-propulsion and the modulation parameter of the potential) at which the average velocity takes its maximal value. The average velocity decreases monotonously with increase of the parameters (the translational diffusion, the rotational diffusion and the particle number).

  1. Modeling of Unsteady Sheet Cavitation on Marine Propeller Blades

    Directory of Open Access Journals (Sweden)

    Spyros A. Kinnas

    2003-01-01

    Full Text Available Unsteady sheet cavitation is very common on marine propulsor blades. The authors summarize a lifting-surface and a surface-panel model to solve for the unsteady cavitating flow around a propeller that is subject to nonaxisymmetric inflow. The time-dependent extent and thickness of the cavity were determined by using an iterative method. The cavity detachment was determined by applying the smooth detachment criterion in an iterative manner. A nonzeroradius developed vortex cavity model was utilized at the tip of the blade, and the trailing wake geometry was determined using a fully unsteady wake-alignment process. Comparisons of predictions by the two models and measurements from several experiments are given.

  2. Many-body dynamics of chemically propelled nanomotors

    Science.gov (United States)

    Colberg, Peter H.; Kapral, Raymond

    2017-08-01

    The collective behavior of chemically propelled sphere-dimer motors made from linked catalytic and noncatalytic spheres in a quasi-two-dimensional confined geometry is studied using a coarse-grained microscopic dynamical model. Chemical reactions at the catalytic spheres that convert fuel to product generate forces that couple to solvent degrees of freedom as a consequence of momentum conservation in the microscopic dynamics. The collective behavior of the many-body system is influenced by direct intermolecular interactions among the motors, chemotactic effects due to chemical gradients, hydrodynamic coupling, and thermal noise. Segregation into high and low density phases and globally homogeneous states with strong fluctuations are investigated as functions of the motor characteristics. Factors contributing to this behavior are discussed in the context of active Brownian models.

  3. Longitudinal Stability Criteria for a Propeller-Driven Aircraft

    Directory of Open Access Journals (Sweden)

    Gil Iosilevskii

    2010-01-01

    Full Text Available The Routh criterion is used to assess longitudinal dynamic stability of a propeller-driven aircraft. Under a few plausible assumptions on possible ranges of the pertinent stability derivatives, it reduces to a pair of simple conditions imposing a traditional aft limit (the forward of the maneuver and the neutral-speed-stability points on the center-of-gravity position and an upper limit on the longitudinal moment of inertia. It is demonstrated that most aircraft have sufficiently small inertia to remain stable as long as their center-of-gravity is properly placed. At the same time, sailplane-like aircraft (as, e.g., long endurance UAVs, with an engine installed at the rear extremity of the aircraft, may have sufficiently high inertia to become unstable regardless of their center-of-gravity placement.

  4. Fluctuations and pattern formation in self-propelled particles.

    Science.gov (United States)

    Mishra, Shradha; Baskaran, Aparna; Marchetti, M Cristina

    2010-06-01

    We consider a coarse-grained description of a collection of self-propelled particles given by hydrodynamic equations for the density and polarization fields. We find that the ordered moving or flocking state of the system is unstable to spatial fluctuations beyond a threshold set by the self-propulsion velocity of the individual units. In this region, the system organizes itself into an inhomogeneous state of well-defined propagating stripes of flocking particles interspersed with low-density disordered regions. Further, we find that even in the regime where the homogeneous flocking state is stable, the system exhibits large fluctuations in both density and orientational order. We study the hydrodynamic equations analytically and numerically to characterize both regimes.

  5. Burning Characteristics of Ammonium-Nitrate-Based Composite Propellants with a Hydroxyl-Terminated Polybutadiene/Polytetrahydrofuran Blend Binder

    Directory of Open Access Journals (Sweden)

    Makoto Kohga

    2012-01-01

    Full Text Available Ammonium-nitrate-(AN- based composite propellants prepared with a hydroxyl-terminated polybutadiene (HTPB/polytetrahydrofuran (PTHF blend binder have unique thermal decomposition characteristics. In this study, the burning characteristics of AN/HTPB/PTHF propellants are investigated. The specific impulse and adiabatic flame temperature of an AN-based propellant theoretically increases with an increase in the proportion of PTHF in the HTPB/PTHF blend. With an AN/HTPB propellant, a solid residue is left on the burning surface of the propellant, and the shape of this residue is similar to that of the propellant. On the other hand, an AN/HTPB/PTHF propellant does not leave a solid residue. The burning rates of the AN/HTPB/PTHF propellant are not markedly different from those of the AN/HTPB propellant because some of the liquefied HTPB/PTHF binder cover the burning surface and impede decomposition and combustion. The burning rates of an AN/HTPB/PTHF propellant with a burning catalyst are higher than those of an AN/HTPB propellant supplemented with a catalyst. The beneficial effect of the blend binder on the burning characteristics is clarified upon the addition of a catalyst. The catalyst suppresses the negative influence of the liquefied binder that covers the burning surface. Thus, HTPB/PTHF blend binders are useful in improving the performance of AN-based propellants.

  6. Media Pembelajaran Global Warming

    OpenAIRE

    Tham, Fikri Jufri; Liliana, Liliana; Purba, Kristo Radion

    2016-01-01

    Computer based learning media is one of the media has an important role in learning. Learning media will be attractive when packaged through interactive media , such as interactive media created in paper manufacture " instructional media global warming" . The advantage gained is that it can increase knowledge, generally educate people to be more concerned about the environment , and also can be a means of entertainment. This application is focused to learn about global warming and packaged in...

  7. Fiber-Optic Continuous Liquid Sensor for Cryogenic Propellant Gauging

    Science.gov (United States)

    Xu. Wei

    2010-01-01

    An innovative fiber-optic sensor has been developed for low-thrust-level settled mass gauging with measurement uncertainty optical fiber to measure liquid level and liquid distribution of cryogenic propellants. Every point of the sensing fiber is a point sensor that not only distinguishes liquid and vapor, but also measures temperature. This sensor is able to determine the physical location of each point sensor with 1-mm spatial resolution. Acting as a continuous array of numerous liquid/vapor point sensors, the truly distributed optical sensing fiber can be installed in a propellant tank in the same manner as silicon diode point sensor stripes using only a single feedthrough to connect to an optical signal interrogation unit outside the tank. Either water or liquid nitrogen levels can be measured within 1-mm spatial resolution up to a distance of 70 meters from the optical interrogation unit. This liquid-level sensing technique was also compared to the pressure gauge measurement technique in water and liquid nitrogen contained in a vertical copper pipe with a reasonable degree of accuracy. It has been demonstrated that the sensor can measure liquid levels in multiple containers containing water or liquid nitrogen with one signal interrogation unit. The liquid levels measured by the multiple fiber sensors were consistent with those virtually measured by a ruler. The sensing performance of various optical fibers has been measured, and has demonstrated that they can survive after immersion at cryogenic temperatures. The fiber strength in liquid nitrogen has also been measured. Multiple water level tests were also conducted under various actual and theoretical vibration conditions, and demonstrated that the signal-to-noise ratio under these vibration conditions, insofar as it affects measurement accuracy, is manageable and robust enough for a wide variety of spacecraft applications. A simple solution has been developed to absorb optical energy at the termination of

  8. Mixing and combustion enhancement of Turbocharged Solid Propellant Ramjet

    Science.gov (United States)

    Liu, Shichang; Li, Jiang; Zhu, Gen; Wang, Wei; Liu, Yang

    2018-02-01

    Turbocharged Solid Propellant Ramjet is a new concept engine that combines the advantages of both solid rocket ramjet and Air Turbo Rocket, with a wide operation envelope and high performance. There are three streams of the air, turbine-driving gas and augment gas to mix and combust in the afterburner, and the coaxial intake mode of the afterburner is disadvantageous to the mixing and combustion. Therefore, it is necessary to carry out mixing and combustion enhancement research. In this study, the numerical model of Turbocharged Solid Propellant Ramjet three-dimensional combustion flow field is established, and the numerical simulation of the mixing and combustion enhancement scheme is conducted from the aspects of head region intake mode to injection method in afterburner. The results show that by driving the compressed air to deflect inward and the turbine-driving gas to maintain strong rotation, radial and tangential momentum exchange of the two streams can be enhanced, thereby improving the efficiency of mixing and combustion in the afterburner. The method of injecting augment gas in the transverse direction and making sure the injection location is as close as possible to the head region is beneficial to improve the combustion efficiency. The outer combustion flow field of the afterburner is an oxidizer-rich environment, while the inner is a fuel-rich environment. To improve the efficiency of mixing and combustion, it is necessary to control the injection velocity of the augment gas to keep it in the oxygen-rich zone of the outer region. The numerical simulation for different flight conditions shows that the optimal mixing and combustion enhancement scheme can obtain high combustion efficiency and have excellent applicability in a wide working range.

  9. Social media management and media environment

    Directory of Open Access Journals (Sweden)

    Šiđanin Iva

    2012-01-01

    Full Text Available The paper deals with the system of services that social media management can offer to a variety of users. As social media systems are emerging, social media management can strengthen teams in social media and help to manage numerous social channels and distribution of social information from one place. Social media management is a system of procedures that are used to manage the flow of information in the environment of social media. This involves connecting with social media like Facebook, Twitter, LinkedIn, Plaxo, Ecademy, YouTube and many others, then the aggregation and management of social data. Social media management services are analysed through various fields, such as managing multiple social media profiles, mail scheduling and filtering, reporting and analytics. Social media management enables managing personal business through social media, which contributes to a significant reduction in expenditures. The paper also discusses the importance of social media management in marketing activities and various forms of social promotion, which allow companies to easily reach their customers.

  10. Flight Validation of the Thermal Propellant Gauging Method used at EADS Astrium

    Science.gov (United States)

    Dandaleix, L.; Ounougha, L.; Jallade, S.

    2004-10-01

    EADS Astrium recently met a major milestone in the field of propellant gauging with the first reorbitation of an Eurostar tanks equipped satellite. It proved successful determining the remaining available propellant mass for spacecraft displacement beyond the customer specified graveyard orbit; thus demonstrating its expertness in Propellant Gauging in correlation with tank residual mass minimization. A critical parameter in satellite operational planning is indeed the accurate knowledge of the on-board remaining propellant mass; basically for the commercial telecommunication missions, where it is the major criterion for lifetime maximization. To provide an accurate and reliable process for measurement of this propellant mass throughout lifetime, EADS Astrium uses a Combination of two independent techniques: The Dead Reckoning Method (maximum accuracy at BOL), based on thrusters flow rate prediction &the Thermal Propellant Gauging Technique, deriving the propellant mass from the tank thermal capacity (Absolute gauging method, with increasing accuracy along lifetime). Then, the present article shows the recent flight validation of the Gauging method obtained for Eurostar E2000 propellant tanks including the validation of the different thermodynamic models. ABBREVIATIONS &ACRONYMS BOL, MOL, EOL: Beginning, Middle &End of Life Cempty: Empty tank thermal inertia [J/K] Chelium: Helium thermal inertia [J/K] Cpropellant: Propellant thermal inertia [J/K] Ct = C1+C2: Total tank thermal inertia (Subscript for upper node and for lower node) [J/K] CPS: Combined Propulsion System DR: Dead Reckoning FM: Flight Model LAE: Liquid Apogee Engine lsb: Least significant byte M0: TPGS Uncertainty component linked to Cempty mox, mfuel: Propellant mass of oxidiser &fuel [kg] Pox, Pfuel: Pressure of oxidiser &fuel [bar] PTA: Propellant Tank Assembly Q: Heater power [W] Qox, Qfuel: Mass flow rate of oxidiser &fuel [kg/s] RCT: Reaction Control Thrusters T0: Spacecraft platform equilibrium

  11. Konservasi Media: Memori Kultural pada Media-Media Lama

    Directory of Open Access Journals (Sweden)

    Aloysius Ranggabumi Nuswantoro

    2015-01-01

    Full Text Available Abstract: Technology boosts the emergence of new communication tools and also creates the dichotomy of old media and new media. At first, it seems like there is nothing wrong with the dichotomy. However, in the context of communication value and meaning, there may be something missing when old media are being abandoned. Not merely the physical manifestation of old media, but rather the work it that contains useful information for the current generation. As a result, today’s people are now losing the root of their thoughts in the past. Thus, conservation is frankly needed to preserve the cultural memory in society Abstrak: Teknologi mendorong munculnya alat-alat komunikasi baru dan membuat dikotomi media lama dan media baru. Sekilas tidak ada yang salah dengan dikotomi tersebut dan konsekuensi yang menyertainya. Namun dalam konteks nilai dan makna komunikasi, ada sesuatu yang hilang ketika media lama ditinggalkan. Bukan semata-mata pada perwujudan fisik media lama, tetapi lebih kepada karya media lama yang memuat informasi berguna bagi generasi saat itu. Akibatnya orang zaman kini kehilangan jejak atau akar pikiran mereka di masa lalu. Maka konservasi media perlu dilakukan untuk mempertahankan memori kultural tersebut.

  12. Design and numerical investigation of swirl recovery vanes for the Fokker 29 propeller

    Directory of Open Access Journals (Sweden)

    Wang Yangang

    2014-10-01

    Full Text Available Swirl recovery vanes (SRVs are a set of stationary vanes located downstream from a propeller, which may recover some of the residual swirl from the propeller, hoping for an improvement in both thrust and efficiency. The SRV concept design for a scaled version representing the Fokker 29 propeller is performed in this paper, which may give rise to a promotion in propulsive performance of this traditional propeller. Firstly the numerical strategy is validated from two aspects of global quantities and the local flow field of the propeller compared with experimental data, and then the exit flow together with the development of propeller wake is analyzed in detail. Three kinds of SRV are designed with multiple circular airfoils. The numerical results show that the swirl behind the propeller is recovered significantly with Model V3, which is characterized by the highest solidity along spanwise, for various working conditions, and the combination of rotor and vane produced 5.76% extra thrust at the design point. However, a lower efficiency is observed asking for a better vane design and the choice of a working point. The vane position is studied which shows that there is an optimum range for higher thrust and efficiency.

  13. A Cis-Lunar Propellant Infrastructure for Flexible Path Exploration and Space Commerce

    Science.gov (United States)

    Oeftering, Richard C.

    2012-01-01

    This paper describes a space infrastructure concept that exploits lunar water for propellant production and delivers it to users in cis-lunar space. The goal is to provide responsive economical space transportation to destinations beyond low Earth orbit (LEO) and enable in-space commerce. This is a game changing concept that could fundamentally affect future space operations, provide greater access to space beyond LEO, and broaden participation in space exploration. The challenge is to minimize infrastructure development cost while achieving a low operational cost. This study discusses the evolutionary development of the infrastructure from a very modest robotic operation to one that is capable of supporting human operations. The cis-lunar infrastructure involves a mix of technologies including cryogenic propellant production, reusable lunar landers, propellant tankers, orbital transfer vehicles, aerobraking technologies, and electric propulsion. This cislunar propellant infrastructure replaces Earth-launched propellants for missions beyond LEO. It enables users to reach destinations with smaller launchers or effectively multiplies the user s existing payload capacity. Users can exploit the expanded capacity to launch logistics material that can then be traded with the infrastructure for propellants. This mutually beneficial trade between the cis-lunar infrastructure and propellant users forms the basis of in-space commerce.

  14. A Study of Fluid Interface Configurations in Exploration Vehicle Propellant Tanks

    Science.gov (United States)

    Zimmerli, Gregory A.; Asipauskas, Marius; Chen, Yongkang; Weislogel, Mark M.

    2010-01-01

    The equilibrium shape and location of fluid interfaces in spacecraft propellant tanks while in low-gravity is of interest to system designers, but can be challenging to predict. The propellant position can affect many aspects of the spacecraft such as the spacecraft center of mass, response to thruster firing due to sloshing, liquid acquisition, propellant mass gauging, and thermal control systems. We use Surface Evolver, a fluid interface energy minimizing algorithm, to investigate theoretical equilibrium liquid-vapor interfaces for spacecraft propellant tanks similar to those that have been considered for NASA's new class of Exploration vehicles. The choice of tank design parameters we consider are derived from the NASA Exploration Systems Architecture Study report. The local acceleration vector employed in the computations is determined by estimating low-Earth orbit (LEO) atmospheric drag effects and centrifugal forces due to a fixed spacecraft orientation with respect to the Earth or Moon, and rotisserie-type spacecraft rotation. Propellant/vapor interface positions are computed for the Earth Departure Stage and Altair lunar lander descent and ascent stage tanks for propellant loads applicable to LEO and low-lunar orbit. In some of the cases investigated the vapor ullage bubble is located at the drain end of the tank, where propellant management device hardware is often located.

  15. Feasibility Study and Demonstration of an Aluminum and Ice Solid Propellant

    Directory of Open Access Journals (Sweden)

    Timothee L. Pourpoint

    2012-01-01

    Full Text Available Aluminum-water reactions have been proposed and studied for several decades for underwater propulsion systems and applications requiring hydrogen generation. Aluminum and water have also been proposed as a frozen propellant, and there have been proposals for other refrigerated propellants that could be mixed, frozen in situ, and used as solid propellants. However, little work has been done to determine the feasibility of these concepts. With the recent availability of nanoscale aluminum, a simple binary formulation with water is now feasible. Nanosized aluminum has a lower ignition temperature than micron-sized aluminum particles, partly due to its high surface area, and burning times are much faster than micron aluminum. Frozen nanoscale aluminum and water mixtures are stable, as well as insensitive to electrostatic discharge, impact, and shock. Here we report a study of the feasibility of an nAl-ice propellant in small-scale rocket experiments. The focus here is not to develop an optimized propellant; however improved formulations are possible. Several static motor experiments have been conducted, including using a flight-weight casing. The flight weight casing was used in the first sounding rocket test of an aluminum-ice propellant, establishing a proof of concept for simple propellant mixtures making use of nanoscale particles.

  16. Back to the future: a history of ACOG in social media's golden age.

    Science.gov (United States)

    DeNicola, Nathaniel; Good, Meadow; Newton, Luke

    2014-12-01

    To chronicle a medical professional society's adoption of innovation and to describe themes pertinent to the adoption. In September 2013, the American College of Obstetricians and Gynecologists (ACOG) published a Committee Opinion on Toxic Environmental Agents that included an infographic and social media awareness campaign. To date, it claims one of the highest total audience reaches for an ACOG Facebook post reaching nearly 18 000 viewers. Despite this powerful promise, ACOG's timely and successful social media campaign did not always appear an obvious strategy. Although social media took hold of popular culture in the early 2000s, social media's professional etiquette remained uncharted and rife, with cautionary tales through the latter half of the decade. Through a thoughtful and dedicated process, the ACOG Fellow and Junior Fellow leadership partnered to navigate the appropriate balance of innovation and prudence that propelled ACOG into social media's golden age, and paved the pathway for more progressive institutional changes.

  17. Green Propellant Test Capabilities of the Altitude Combustion Stand at the NASA Glenn Research Center

    Science.gov (United States)

    Kubiak, Jonathan M.; Arnett, Lori A.

    2016-01-01

    The NASA Glenn Research Center (GRC) is committed to providing simulated altitude rocket test capabilities to NASA programs, other government agencies, private industry partners, and academic partners. A primary facility to support those needs is the Altitude Combustion Stand (ACS). ACS provides the capability to test combustion components at a simulated altitude up to 100,000 ft. (approx.0.2 psia/10 Torr) through a nitrogen-driven ejector system. The facility is equipped with an axial thrust stand, gaseous and cryogenic liquid propellant feed systems, data acquisition system with up to 1000 Hz recording, and automated facility control system. Propellant capabilities include gaseous and liquid hydrogen, gaseous and liquid oxygen, and liquid methane. A water-cooled diffuser, exhaust spray cooling chamber, and multi-stage ejector systems can enable run times up to 180 seconds to 16 minutes. The system can accommodate engines up to 2000-lbf thrust, liquid propellant supply pressures up to 1800 psia, and test at the component level. Engines can also be fired at sea level if needed. The NASA GRC is in the process of modifying ACS capabilities to enable the testing of green propellant (GP) thrusters and components. Green propellants are actively being explored throughout government and industry as a non-toxic replacement to hydrazine monopropellants for applications such as reaction control systems or small spacecraft main propulsion systems. These propellants offer increased performance and cost savings over hydrazine. The modification of ACS is intended to enable testing of a wide range of green propellant engines for research and qualification-like testing applications. Once complete, ACS will have the capability to test green propellant engines up to 880 N in thrust, thermally condition the green propellants, provide test durations up to 60 minutes depending on thrust class, provide high speed control and data acquisition, as well as provide advanced imaging and

  18. Towards the Development of Low Power Arcjet for Use with Green Propellant

    Science.gov (United States)

    Moeller, Trevor M.

    2017-01-01

    Conventional arcjet propellants are hydrazine and ammonia. Both are toxic and environmentally unfriendly, requiring the use of complicated handling logistics and increased cost. If successfully demonstrated in arcjets, the use of green propellants would alleviate these issues. This paper details improvements made to the design of a low-power arcjet to be used in testing. Diagnostic tools to be used to assess thruster performance were also developed. These include emission spectroscopy for the detection of thruster insulator erosion and a two-cord heterodyne laser interferometer to measure electron number densities and estimate the exit velocity of the propellant.

  19. Investigation on hydrodynamic performance of a marine propeller in oblique flow by RANS computations

    Directory of Open Access Journals (Sweden)

    Jianxi Yao

    2015-01-01

    Full Text Available This paper presents a numerical study on investigating on hydrodynamic characteristics of a marine propeller in oblique flow. The study is achieved by RANS simulations on an open source platform - OpenFOAM. A sliding grid approach is applied to compute the rotating motion of the propeller. Total force and moment acting on blades, as well as average force distributions in one revolution on propeller disk, are obtained for 70 cases of com- binations of advance ratios and oblique angles. The computed results are compared with available experimental data and discussed.

  20. Local modes analysis of a rotating marine ship propeller with higher order harmonic elements

    Science.gov (United States)

    Feng, Chen; Yong, Chen; Hongxing, Hua

    2016-09-01

    An annular harmonic finite element for the computation of the local modes of a pretwisted ship propeller is developed. The elements take into account both the gyroscopic effect and centrifugal stiffening of the propeller blades. The displacement field is expressed by a truncated Fourier series along the angle and by polynomial shape functions in the radial direction. As an example, the dynamic behaviour, i.e. the nature frequency and local modes, of a ship propeller is studied, and compared with ANSYS, both of which have good consistency.

  1. Radiated Sound of a High-Speed Water-Jet-Propelled Transportation Vessel.

    Science.gov (United States)

    Rudd, Alexis B; Richlen, Michael F; Stimpert, Alison K; Au, Whitlow W L

    2016-01-01

    The radiated noise from a high-speed water-jet-propelled catamaran was measured for catamaran speeds of 12, 24, and 37 kn. The radiated noise increased with catamaran speed, although the shape of the noise spectrum was similar for all speeds and measuring hydrophone depth. The spectra peaked at ~200 Hz and dropped off continuously at higher frequencies. The radiated noise was 10-20 dB lower than noise from propeller-driven ships at comparable speeds. The combination of low radiated noise and high speed could be a factor in the detection and avoidance of water-jet-propelled ships by baleen whales.

  2. Pre-Swirl Stator and Propeller Design for Varying Operating Conditions

    DEFF Research Database (Denmark)

    Saettone, Simone; Regener, Pelle Bo; Andersen, Poul

    2016-01-01

    blades ahead of the propeller.This paper describes the hydrodynamic design of apre-swirl stator with radially variable pitch, paired with aconventional propeller. The aim is to achieve the highest possible effciency in various operating conditions, and to avoid effciency penalties in off-design operation.......To investigate the propeller and stator designs and configurations in different operating conditions, the computationally inexpensive vortex-lattice method is used a sa first step to optimize the geometry in an initial parameter study. Then the flow over hull, stator and propelleris simulated in a CFD...

  3. The Media Teacher's Handbook

    Science.gov (United States)

    Scarratt, Elaine, Ed.; Davison, Jon, Ed.

    2011-01-01

    "The Media Teacher's Handbook" is an indispensible guide for all teachers, both specialist and non-specialist, delivering Media Studies and media education in secondary schools and colleges. It is the first text to draw together the three key elements of secondary sector teaching in relation to media study--the "theoretical",…

  4. Media Literacy Bibliography.

    Science.gov (United States)

    Duncan, Barry

    1989-01-01

    Provides an up-to-date bibliography of resources available for teaching media literacy. Groups resources into the areas of media education methodology, mass media texts, general background, television, film, the news and medium of print, advertising, gender and the media, popular culture, popular music and rock video, periodicals, and…

  5. Media Violence and Children.

    Science.gov (United States)

    Groebel, Jo

    1998-01-01

    Presents the results of the UNESCO global study on media violence and children which was conducted between 1996 and 1997. Highlights include the role of the media, media heroes as role models, media violence and aggression, differences by gender, rural versus urban environments, the pervasiveness of television, and recommendations. (Author/LRW)

  6. Open Media Science

    DEFF Research Database (Denmark)

    Møller Moltke Martiny, Kristian; Pedersen, David Budtz; Hansted, Allan Alfred Birkegaard

    2016-01-01

    and extend into a fully-fledged Open Media movement engaging with new media and non-traditional formats of science communication. We discuss two cases where experiments with open media have driven new collaborations between scientists and documentarists. We use the cases to illustrate different advantages...... of using open media to face the challenges of OS....

  7. Media en rampen

    NARCIS (Netherlands)

    Vasterman, P.L.M.

    2008-01-01

    Media and disasters. Disasters have always been breaking news, but in the current competitive media landscape the media have an interest in expanding the disaster into a news spectacle, spanning several weeks afterwards. After the immediate on the spot reporting, the media will concentrate on two

  8. The Media Mixer

    DEFF Research Database (Denmark)

    Vestergaard, Vitus; Mortensen, Christian Hviid

    2011-01-01

    throughout the Internet, most notably on web 2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here the museum users can produce, deconstruct, reconstruct and finally publish and share digital media...... content. The media content is created by the user in the museum's physical environment, but it can be mixed with material from web archives. It is the intention that the users learn about media through participatory and creative processes with media where the borders between producing, playing...... and learning are blurred....

  9. CONSTRUCTION SELF-PROPELLED PNEUMOPUNCHERS WITH LOCKING MECHANISM

    Directory of Open Access Journals (Sweden)

    V. K. Perederey

    2016-01-01

    Full Text Available The paper reveals one of possible methods for higher productivity and reliability of building self-propelled pneumopunchers which are intended for making holes in soil while using trenchless method and constructing various engineering communications under car, tram and rail lines, airport runways. A new design of building pneumopuncher with increased productivity due to higher speed for hole formation in soil and its reliability has been presented in the paper. A formula for determination of displacement increment for a new pneumopuncher in comparison with the conventional one has been obtained in the paper. The paper describes a design and operation principal of the building self-propelled pneumopuncher which is equipped with a locking mechanism with the purpose to neutralize action of soil elastic forces and reactive repulsive force. The locking mechanism keeps the pneumopuncher in the hole. The pneumopuncher consists of a body with anvil, movable hammer, a manifold which is set in axial deepening of the hammer, a nut and a locking mechanism. Improvement of operational pneumopuncher reliability is attained due to the fact that the locking mechanism is made in the form of two coaxially positioned inner and outer cups having a common basis. A piston is installed in the middle of the inner cup, a spring is fixed over the piston and a rod with a breaking shoe is positioned at the end. Height of the inner cup is less the outer cup height and there is an annular cavity between them which is connected with a chamber. The chamber is formed by the piston, the inner cup and the manifold. The annular cavity through an opening in the inner cup wall, two sylphons, a channel in the nut end and an opening in the vertical wall of the manifold are connected with a chamber of operating stroke. The sylphons are placed between the outer cup and the nut, between the nut and the manifold. Differential equations for movement of pneumopuncher in soil have been

  10. Bismuth Propellant Feed System Development at NASA-MSFC

    Science.gov (United States)

    Polzin, Kurt A.

    2007-01-01

    NASA-MSFC has been developing liquid metal propellant feed systems capable of delivering molten bismuth at a prescribed mass flow rate to the vaporizer of an electric thruster. The first such system was delivered to NASA-JPL as part of the Very High Isp Thruster with Anode Layer (VHITAL) program. In this system, the components pictured were placed in a vacuum chamber and heated while the control electronics were located outside the chamber. The system was successfully operated at JPL in conjunction with a propellant vaporizer, and data was obtained demonstrating a new liquid bismuth flow sensing technique developed at MSFC. The present effort is aimed at producing a feed-system for use in conjunction with a bismuth-fed Hall thruster developed by Busek Co. Developing this system is more ambitious, however, in that it is designed to self-contain all the control electronics inside the same vacuum chamber as an operating bismuth-fed thruster. Consequently, the entire system, including an on-board computer, DC-output power supplies, and a gas-pressurization electro-pneumatic regulator, must be designed to survive a vacuum environment and shielded to keep bismuth plasma from intruding on the electronics and causing a shortcircuit. In addition, the hot portions of the feed system must be thermally isolated from the electronics to avoid failure due to high heat loads. This is accomplished using a thermal protection system (TPS) consisting of multiple layers of aluminum foil. The only penetrations into the vacuum chamber are an electrically isolated (floating) 48 VDC line and a fiberoptic line. The 48 VDC provides power for operation of the power supplies and electronics co-located with the system in the vacuum chamber. The fiberoptic Ethernet connection is used to communicate user-input control commands to the on-board computer and transmit real-time data back to the external computer. The partially assembled second-generation system is shown. Before testing at Busek, a

  11. Social media networking: blogging.

    Science.gov (United States)

    Schneider, Andrew; Jackson, Rem; Baum, Neil

    2010-01-01

    Social media networking is not your teenager's social media. It is a powerful tool that will change the way you communicate with your patients. This article will review the impact of social media and how social media can be a valuable tool for your medical practice. This is the first of a three-part article on social media and will discuss the use of blogging for medical practices.

  12. Understanding Social Media Logic

    OpenAIRE

    José van Dijck; Thomas Poell

    2013-01-01

    Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media log...

  13. Media multitasking in adolescence

    OpenAIRE

    Cain, Matthew S.; Finn, Amy S.; Leonard, Julia; Gabrieli, John D. E.

    2016-01-01

    Media use has been on the rise in adolescents overall, and in particular, the amount of media multitasking—multiple media consumed simultaneously, such as having a text message conversation while watching TV—has been increasing. In adults, heavy media multitasking has been linked with poorer performance on a number of laboratory measures of cognition, but no relationship has yet been established between media-multitasking behavior and real-world outcomes. Examining individual differences acro...

  14. Retrospective comparison of direct in-bore magnetic resonance imaging (MRI)-guided biopsy and fusion-guided biopsy in patients with MRI lesions which are likely or highly likely to be clinically significant prostate cancer.

    Science.gov (United States)

    Venderink, Wulphert; van der Leest, Marloes; van Luijtelaar, Annemarijke; van de Ven, Wendy J M; Fütterer, Jurgen J; Sedelaar, J P Michiel; Huisman, Henkjan J

    2017-12-01

    To compare clinically significant prostate cancer (csPCa) detection rates between magnetic resonance imaging (MRI)-transrectal ultrasound (TRUS) fusion-guided prostate biopsy (FGB) and direct in-bore MRI-guided biopsy (MRGB). We performed a comparison of csPCa detection rates between FGB and MRGB. Included patients had (1) at least one prior negative TRUS biopsy; (2) a Prostate Imaging Reporting and Data System (PI-RADS) 4 or 5 lesion and (3) a lesion size of ≥8 mm measured in at least one direction. We considered a Gleason score ≥7 being csPCa. Descriptive statistics with 95% confidence intervals (CI) were used to determine any differences. We included 51 patients with FGB (59 PI-RADS 4 and 41% PI-RADS 5) and 227 patients with MRGB (34 PI-RADS 4 and 66% PI-RADS 5). Included patients had a median age of 69 years (IQR, 65-72) and a median PSA level of 11.0 ng/ml (IQR, 7.4-15.1) and a median age of 67 years (IQR, 61-70), the median PSA 12.8 ng/ml (IQR, 9.1-19.0) within the FGB and the MRGB group, respectively. Detection rates of csPCA did not differ significantly between FGB and MRGB, 49 vs. 61%, respectively. We did not detect significant differences between FGB and MRGB in the detection of csPCa. The differences in detection ratios between both biopsy techniques are narrow with an increasing lesion size. This study warrants further studies to optimize selection of best biopsy modality.

  15. Resonant Laser Ignition Study of HAN-HEHN Propellant Mixture (Preprint)

    National Research Council Canada - National Science Library

    Alfano, Angelo J; Mills, Jeffrey D; Vaghjiani, Ghanshyam L

    2008-01-01

    ...) - hydroxyethylhydrazinium nitrate (HEHN) mixtures. This prototypical ionic liquid propellant was successfully and reliably ignited/detonated under confinement with single laser pulses in the mid IR at 2.94 and 10.6 microns...

  16. Technologies for propelled hypersonic flight: Technologies des vols hypersoniques propulsés

    National Research Council Canada - National Science Library

    2006-01-01

    These reports document the results of the Applied Vehicle Technology Panel Working Group 10, Subgroups 1, 2, and 3, who aimed to address selected critical issues related to propelled hypersonic flight...

  17. Propeller alustab tuuri vürsti lapsepõlvelinnast / Allar Viivik

    Index Scriptorium Estoniae

    Viivik, Allar

    2009-01-01

    Tänavu 30. juubelit tähistavast punkansamblist Propeller eesotsas Peeter Volkonskiga, kes alustavad koos ansambliga Kosmikud 30. oktoobril Keila kultuurikeskusest üle-eestilist juubelituuri, esinejatest

  18. In-Depth Chemistry in Plasma-Exposed M30 and JA2 Gun Propellants

    National Research Council Canada - National Science Library

    Pesce-Rodriguez, Rose

    2001-01-01

    ...) method to detect low levels of NO in the propellant. It appears that for M30, profiles for radiation-induced denitration of nitrate esters are consistent with Beer's law, and that effects occur as deep...

  19. Integrated MLI: Advanced Thermal Insulation for Propellant Storage and Transfer Testbed Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic propellants, orbital cryogenic fuel depots and the ability to store, transfer, handle and refuel spacecraft in orbit are critical to NASA future missions...

  20. Cathode for Electric Space Propulsion Utilizing Iodine as Propellant, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a hollow reservoir cathode suitable for use in ion or Hall thrusters which utilizes iodine as a propellant. Reservoir cathodes have several unique...

  1. An Evaluation of Green Propellants for an ICBM Post-Boost Propulsion System

    National Research Council Canada - National Science Library

    Mavris, Dimitri

    2000-01-01

    .... Many low toxicity "green" propellants have been developed which hold the potential of increasing the safety and lowering the operation and support costs of liquid-fueled strategic missile propulsion systems...

  2. Parametric Optimization of Ares I Propellant Slosh Characteristics Using Frequency Response Criteria

    Science.gov (United States)

    Orr, Jeb S.; Hall, Charles E.

    2009-01-01

    A novel technique for developing propellant slosh damping requirements with respect to the stability characteristics of large flexible launch vehicles is presented. A numerical algorithm is devised which allows an automated software program to rapidly converge to pseudo-optimal solutions that minimize required propellant slosh damping for multiple tanks while maintaining constraints on the frequency response characteristics of a particular open-loop plant transfer function. An implementation of the algorithm using a high-order linear model of the Ares I plant dynamics considers all relevant dynamic interactions of flexible body modes, propellant slosh, and nozzle inertia effects. A high-resolution propellant damping requirements table is produced that can be used for baffle design. The method is demonstrated to provide exceptional speed and accuracy when compared with the alternative human-in-the-loop approach.

  3. RANS simulation of cavitation and hull pressure fluctuation for marine propeller operating behind-hull condition

    Directory of Open Access Journals (Sweden)

    Kwang-Jun Paik

    2013-12-01

    Full Text Available Simulations of cavitation flow and hull pressure fluctuation for a marine propeller operating behind a hull using the unsteady Reynolds-Averaged Navier-Stokes equations (RANS are presented. A full hull body submerged under the free surface is modeled in the computational domain to simulate directly the wake field of the ship at the propeller plane. Simulations are performed in design and ballast draught conditions to study the effect of cavitation number. And two propellers with slightly different geometry are simulated to validate the detectability of the numerical simulation. All simulations are performed using a commercial CFD software FLUENT. Cavitation patterns of the simulations show good agreement with the experimental results carried out in Samsung CAvitation Tunnel (SCAT. The simulation results for the hull pressure fluctuation induced by a propeller are also compared with the experimental results showing good agreement in the tendency and amplitude, especially, for the first blade frequency.

  4. An estimation method of full scale performance for pulling type podded propellers

    Directory of Open Access Journals (Sweden)

    Hyoung-Gil Park

    2014-12-01

    Full Text Available This paper presents a new estimation method of full scale propulsive performance for the pulling type podded propeller. In order to estimate the drag of pod housing, a drag velocity ratio, which includes the effects of podded propeller loading and Reynolds number, is presented and evaluated through the comparison of model test and numerical analysis. By separating the thrust of propeller blade and the drag of pod housing, extrapolation method of pod housing drag to full scale is deduced, and correction method of propeller blade thrust and torque to full scale is presented. This study utilized the drag coefficient ratio of the pod housing as a measure for expanding it to full scale, but in order to increase the accuracy of performance evaluation, additional study is necessary on the method for the full scale expansion via separating the drag of pod body, strut and fin which consist the pod housing.

  5. Modeling Turbulence Effects in Cryogenic Propellant Tank Thermal Management, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Control and management of cryogenic propellant tank pressures in low gravity is an important technical challenge to overcome for future long duration space missions....

  6. Temperatures and Species Concentration in Propellant Dark Zones via Fitting Infrared (IR) Spectral Absorption Data

    National Research Council Canada - National Science Library

    Vanderhoff, J

    1997-01-01

    In a continuing investigation of the dark zone of double-base and nitramine propellants during self-sustained combustion, least-squares fitting has been developed and updated simulations of infrared (IR...

  7. Characterization of a Green Solid Electric Propellant Microthruster for Small Spacecraft

    Data.gov (United States)

    National Aeronautics and Space Administration — The development of Solid Electric Propellants is an emerging topic of research with major implications in the field of space propulsion from the micro to macro...

  8. Seat Vibration in Military Propeller Aircraft: Characterization, Exposure Assessment, and Mitigation

    National Research Council Canada - National Science Library

    Smith, Suzanne D

    2006-01-01

    There have been increasing reports of annoyance, fatigue, and even neck and back pain during prolonged operation of military propeller aircraft, where persistent multi-axis vibration occurs at higher...

  9. Lithium Propellant Purification and Filtration System For LFA and MPD Thrusters, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Lithium has been proposed as an attractive metal propellant for advanced nuclear-electric propulsion missions in the outer solar system. While it is low molecular...

  10. Design and testing of the Space Station Freedom Propellant Tank Assembly

    Science.gov (United States)

    Dudley, D. D.; Thonet, T. A.; Goforth, A. M.

    1992-01-01

    Propellant storage and management functions for the Propulsion Module of the U.S. Space Station Freedom are provided by the Propellant Tank Assembly (PTA). The PTA consists of a surface-tension type propellant acquisition device contained within a welded titanium pressure vessel. The PTA design concept was selected with high reliability and low program risk as primary goals in order to meet stringent NASA structural, expulsion, fracture control and reliability requirements. The PTA design makes use of Shuttle Orbital Maneuvering System and Peacekeeper Propellant Storage Assembly design and analysis techniques. This paper summarizes the PTA design solution and discusses the underlying detailed analyses. In addition, design verification and qualification test activities are discussed.

  11. The Effects of Hull Pitching Motions and Waves on Periodic Propeller Blade Loads.

    Science.gov (United States)

    1982-09-01

    1 INTRODUCTION.....................................1 EXPERIMENTAL TECHNIQUES.................................4 DYNAMOMETRY ...loads. 3 II. EXPERIMENTAL TECHNIQUES A. Dynamometry All experiments were conducted using the hull and propeller shown in Figure 1 on Carriage II at

  12. Environmentally Friendly ̀Green' Propellant for the Medium Caliber Training Rounds

    National Research Council Canada - National Science Library

    Manning, T. G; Thompson, D; Ellis, M; Lieb, R; Leadore, M; Colburn, J; Homan, B. E; Worrell, D. A; Moran, K. B; Ritchie, S. J

    2006-01-01

    U.S. Army TACOM-ARDEC has teamed with the U.S. Army Research Laboratory in developing an environmentally friendly "green" propellant with improved insensitive munitions characteristics for use in medium caliber ammunition...

  13. HIGH ENERGY REPLACEMENT FOR TEFLON PROPELLANT IN PULSED PLASMA THRUSTERS, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This program will utilize a well-characterized Pulsed Plasma Thruster (PPT) to test experimental high-energy extinguishable solid propellants (HE), instead of...

  14. Microwave Dielectric Properties of XM46 and a Surrogate Liquid Propellant

    National Research Council Canada - National Science Library

    Bossoli, Robert

    1998-01-01

    .... The dielectric constant (permittivity) of LP was determined in support of possible studies of the feasibility of using microwave energy to preheat LP for more consistent electric ignition in regenerative liquid propellant guns (RLPG...

  15. Modified Collins Cryocooler for Cryo-Propellant Thermal Management, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Future lunar and planetary explorations will require the storage of cryogenic propellants, particularly liquid oxygen (LOX) and liquid hydrogen (LH2), in low earth...

  16. Modified Collins Cryocooler for Cryo-Propellant Thermal Management, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Future lunar and planetary explorations will require the storage of cryogenic propellants, particularly liquid oxygen (LOX) and liquid hydrogen (LH2), in low earth...

  17. HIGH ENERGY REPLACEMENT FOR TEFLON PROPELLANT IN PULSED PLASMA THRUSTERS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This program will utilize a well-characterized Pulsed Plasma Thruster (PPT) to test experimental high-energy extinguishable solid propellants (HE), instead of...

  18. Materials & Engineering: Propelling Innovation MRS Bulletin Special Issue Session

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Gopal [Materials Research Society, Warrendale, PA (United States)

    2016-05-06

    Materials enable engineering; and, engineering in turn depends on materials to transform design concepts and equations into physical entities. This relationship continues to grow with expanding societal demand for new products and processes. MRS Bulletin, a publication of the Materials Research Society (MRS) and Cambridge University Press, planned a special issue for December 2015 on Materials and Engineering: Propelling Innovation. This special issue of MRS Bulletin captured the unique relationship between materials and engineering, which are closely intertwined. A special half day session at the 2015 MRS Fall Meeting in Boston captured this discussion through presentations by high level experts followed by a panel discussion on what it takes to translate materials discoveries into products to benefit society. The Special Session included presentations by experts who are practitioners in materials as well as engineering applications, followed by a panel discussion. Participants discussed state-of-the-art in materials applications in engineering, as well as how engineering needs have pushed materials developments, as also reflected in the 20 or so articles published in the special issue of MRS Bulletin. As expected, the discussions spanned the broad spectrum of materials and provided very strong interdisciplinary interactions and discussions by participants and presenters.

  19. Effect of Propeller Angle Relative to Flow on Aerodynamic Characteristics

    Science.gov (United States)

    Schueller, Joseph; Hubner, Paul

    2017-11-01

    As the interest in small unmanned air systems (UASs) for delivery and surveillance grows, new hybrid designs are being studied to take advantage of both quadcopters and fixed-wing aircraft. The tiltrotor design is able to combine the vertical take-off, hover, and landing of a multi-rotor copter with the efficiency of forward flight of a conventional airplane. However, literature documenting aerodynamic performance of the rotor as it rotates between the forward-flight and hover positions, especially in this low Reynolds number range, is limited. This data is critical for validating computational models and developing safe transition corridors. The objective of this research was to design, build and test a rotor thrust stand capable of rotating between the forward-flight and hover configurations suitable for senior design studies at low Reynolds number research. The poster covers the design of the rotating mechanism, the range and resolution of the load cell, and the thrust, torque and efficiency results for a conventional UAS motor and propeller for various advance ratios and thrust-line orientations. NSF Grant: EEC 1659710.

  20. Modeling the Behavior of Self-Propelled Microcapsules

    Science.gov (United States)

    Bhattacharya, Amitabh; Berk Usta, O.; Balazs, Anna C.

    2009-03-01

    Biological cells can perform complex tasks by signaling and moving autonomously in their environment. We study a system of self-propelled microcapsules, first proposed by Usta et al (2008), that mimics this process. It consists of a signaling and target microcapsule placed close to an adhesive substrate and immersed in fluid. The signaling microcapsule encases nanoparticles, which, when released, modifies the adhesive strength of the substrate. The adhesion gradients in the substrate, along with hydrodynamic interactions among the capsules, gives rise to a sustained motion of the microcapsules. In this work, we perform simulations (based on lattice Boltzmann method for the fluid and random walk simulation for nanoparticles) of several signal-target configurations, consisting of two or more rigid capsules. In particular, we examine a configuration consisting of a single signaling capsule pushing multiple target capsules in a single file. For a constant release rate of nanoparticles, the velocity of the train of capsules asymptotes to a constant value at large times. Using a low-order analytical model for this system, we show that there is a simple relationship between this asymptotic velocity and the parameters in the system (e.g. number of capsules, release rate of nanoparticles, viscosity of fluid, adhesive strength of substrate etc.).

  1. Stress analysis of rotating propellers subject to forced excitations

    Science.gov (United States)

    Akgun, Ulas

    Turbine blades experience vibrations due to the flow disturbances. These vibrations are the leading cause for fatigue failure in turbine blades. This thesis presents the finite element analysis methods to estimate the maximum vibrational stresses of rotating structures under forced excitation. The presentation included starts with the derived equations of motion for vibration of rotating beams using energy methods under the Euler Bernoulli beam assumptions. The nonlinear large displacement formulation captures the centrifugal stiffening and gyroscopic effects. The weak form of the equations and their finite element discretization are shown. The methods implemented were used for normal modes analyses and forced vibration analyses of rotating beam structures. The prediction of peak stresses under simultaneous multi-mode excitation show that the maximum vibrational stresses estimated using the linear superposition of the stresses can greatly overestimate the stresses if the phase information due to damping (physical and gyroscopic effects) are neglected. The last section of this thesis also presents the results of a practical study that involves finite element analysis and redesign of a composite propeller.

  2. Inverse Leidenfrost effect: self-propelling drops on a bath

    Science.gov (United States)

    Gauthier, Anais; van der Meer, Devaraj; Lohse, Detlef; Physics of Fluids Team

    2017-11-01

    When deposited on very hot solid, volatile drops can levitate over a cushion of vapor, in the so-called Leidenfrost state. This phenomenon can also be observed on a hot bath and similarly to the solid case, drops are very mobile due to the absence of contact with the substrate that sustains them. We discuss here a situation of ``inverse Leidenfrost effect'' where room-temperature drops levitate on a liquid nitrogen pool - the vapor is generated here by the bath sustaining the relatively hot drop. We show that the drop's movement is not random: the liquid goes across the bath in straight lines, a pattern only disrupted by elastic bouncing on the edges. In addition, the drops are initially self-propelled; first at rest, they accelerate for a few seconds and reach velocities of the order of a few cm/s, before slowing down. We investigate experimentally the parameters that affect their successive acceleration and deceleration, such as the size and nature of the drops and we discuss the origin of this pattern.

  3. The assessment of lethal propeller strike injuries in sea mammals.

    Science.gov (United States)

    Byard, Roger W; Winskog, Calle; Machado, Aaron; Boardman, Wayne

    2012-04-01

    Assessment of injuries in marine mammals may be required to help authorities determine whether human activity was involved. Three cases of marine animal deaths involving propeller blade strikes are reported to demonstrate characteristic features of such cases and diagnostic difficulties that may occur. Case 1: A juvenile New Zealand fur seal (Arctocephalus forsteri) suffered two parallel linear incised wounds of the flank and died following small intestinal herniation. Case 2: An Indo-Pacific bottlenose dolphin neonate (Tursiops aduncus) died from a deeply incised wound of the left side of the head with shattering of the skull and laceration of the underlying brain.Case 3: An adult female Indo-Pacific bottlenose dolphin (T. aduncus) died from two parallel chop wounds to the torso with opening of the thoracic and abdominal cavities with fractures of the ribs and vertebrae. Given that some animals may recover, and that the carcasses of those that are killed may simply not be found or reported, it is impossible to provide an estimate of the incidence of this type of injury amongst wild sea mammals. In cases that do come to forensic attention accurate evaluation of the type of injury may potentially have great medicolegal significance. Post-mortem putrefaction and post-mortem feeding by other sea animals may complicate assessments. Copyright © 2012 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  4. Non-linear analysis of solid propellant burning rate behavior

    Energy Technology Data Exchange (ETDEWEB)

    Junye Wang [Zhejiang Univ. of Technology, College of Mechanical and Electrical Engineering, Hanzhou (China)

    2000-07-01

    The parametric analysis of the thermal wave model of the non-steady combustion of solid propellants is carried out under a sudden compression. First, to observe non-linear effects, solutions are obtained using a computer under prescribed pressure variations. Then, the effects of rearranging the spatial mesh, additional points, and the time step on numerical solutions are evaluated. Finally, the behaviour of the thermal wave combustion model is examined under large heat releases (H) and a dynamic factor ({beta}). The numerical predictions show that (1) the effect of a dynamic factor ({beta}), related to the magnitude of dp/dt, on the peak burning rate increases as the value of beta increases. However, unsteady burning rate 'runaway' does not appear and will return asymptotically to ap{sup n}, when {beta}{>=}10.0. The burning rate 'runaway' is a numerical difficulty, not a solution to the models. (2) At constant beta and m, the amplitude of the burning rate increases with increasing H. However, the increase in the burning rate amplitude is stepwise, and there is no apparent intrinsic instability limit. A damped oscillation of burning rate occurs when the value of H is less. However, when H>1.0, the state of an intrinsically unstable model is composed of repeated, amplitude spikes, i.e. an undamped oscillation occurs. (3) The effect of the time step on the peak burning rate increases as H increases. (Author)

  5. Investigations of surface treatment of propellant grains using labelled substances

    International Nuclear Information System (INIS)

    Meier, H.; Boesche, D.; Zeitler, G.; Zimmerhackl, E.; Hecker, W.; Tschirwitz, U.

    1979-01-01

    First, a report on the current state of research and knowledge about the deterring process characterized by a diffusion of deterrents into nitrocellulose propellant grains is given. Furthermore, it is shown that the migration of phlegmatizers into nitrocellulose grains can be identified by applying the radiotracer technique: when deterrents (di-n-butylphthalate (DBP), di-n-octylphthalate (DOP)) are labelled with carbon-14, the distribution of these compounds in nitrocellulose grains can be measured by means of profile sectioning technique in conjunction with beta scintillation metering. These measurements yield values for diffusions coefficients D (10 -10 - 10 -8 [cm 2 sec -1 ]), activation energies Q (16,1 - 5,3 [kcal/mol]) and frequency factors Do (10 2 - 10 -5 [cm 2 sec -1 ]). Moreover, by taking into account the concentration dependence of diffusion coefficients general equations have been derived for describing the migration behaviour of deterrents among various conditions of deterring processes (e.g., temperature, time and concentration). Therefore, it is possible to classify deterrent systems in terms of their trend to migrate (DBP/C 2 H 5 OH > DBP/C 3 H 7 OH > DOP/C 2 H 5 OH > DOP/C 3 H 7 OH) and to calculate the depth of penetration into a nitrocellulose sphere. In addition, the concentration profile of phlegmatizers in the grain can be approximately predicted. Furthermore, in the light of the available data also a model of the migration mechanism which assumes a moving boundary is discussed. (orig.) [de

  6. Fuel-cell-propelled submarine-tanker-system study

    International Nuclear Information System (INIS)

    Court, K.E.; Kumm, W.H.; O'Callaghan, J.E.

    1982-06-01

    This report provides a systems analysis of a commercial Arctic Ocean submarine tanker system to carry fossil energy to markets. The submarine is to be propelled by a modular Phosphoric Acid Fuel Cell system. The power level is 20 Megawatts. The DOE developed electric utility type fuel cell will be fueled with methanol. Oxidant will be provided from a liquid oxygen tank carried onboard. The twin screw submarine tanker design is sized at 165,000 deadweight tons and the study includes costs and an economic analysis of the transport system of 6 ships. The route will be under the polar icecap from a loading terminal located off Prudhoe Bay, Alaska to a transshipment facility postulated to be in a Norwegian fjord. The system throughput of the gas-fed methanol cargo will be 450,000 barrels per day. The total delivered cost of the methanol including well head purchase price of natural gas, methanol production, and shipping would be $25/bbl from Alaska to the US East Coast. Of this, the shipping cost is $6.80/bbl. All costs in 1981 dollars

  7. New analytical techniques to facilitate preformulation screening in propellant systems.

    Science.gov (United States)

    Mogalian, Erik; Kuehl, Philip J; Myrdal, Paul B

    2007-08-01

    The objective of these studies was to investigate the applicability of an online direct inject HPLC method for the preformulation screening of pharmaceutical agents in pressurized metered dose inhalers (MDIs). The technique was initially utilized for the solubility determination of solid solutes. This study explores the extension of the online direct inject method for the evaluation of drug stability in propellant systems as well as for the analysis of MDI vials crimped with metered valves. Through-life content analysis confirmed that a single vial may be repeatedly sampled, thus facilitating the stability evaluation of a single unit over time. The method was successfully used for evaluating the stability of a model drug, as a function of several different formulation configurations, with minimal sample numbers. Additionally, studies determined that after modifications were made to the injection coupler, the technique was also feasible for use with 50 and 100 microL metered valves, however further modifications are necessary for 25 microL valves.

  8. Fuel-cell-propelled submarine-tanker-system study

    Energy Technology Data Exchange (ETDEWEB)

    Court, K E; Kumm, W H; O' Callaghan, J E

    1982-06-01

    This report provides a systems analysis of a commercial Arctic Ocean submarine tanker system to carry fossil energy to markets. The submarine is to be propelled by a modular Phosphoric Acid Fuel Cell system. The power level is 20 Megawatts. The DOE developed electric utility type fuel cell will be fueled with methanol. Oxidant will be provided from a liquid oxygen tank carried onboard. The twin screw submarine tanker design is sized at 165,000 deadweight tons and the study includes costs and an economic analysis of the transport system of 6 ships. The route will be under the polar icecap from a loading terminal located off Prudhoe Bay, Alaska to a transshipment facility postulated to be in a Norwegian fjord. The system throughput of the gas-fed methanol cargo will be 450,000 barrels per day. The total delivered cost of the methanol including well head purchase price of natural gas, methanol production, and shipping would be $25/bbl from Alaska to the US East Coast. Of this, the shipping cost is $6.80/bbl. All costs in 1981 dollars.

  9. Development Activities on an Advanced Propellant Flow Control Unit

    Science.gov (United States)

    Noci, G.; Siciliano, P.; Fallerini, L.; Kutufa, N.; Rivetti, A.; Galassi, C.; Bruschi, P.; Piotto, M.

    2004-10-01

    A new generation of propellant control equipment for electric propulsion systems is needed in order to improve performance and operating ranges, symplify h/w configuration, reduce mass and dimensions, eliminate mass flow ripple, reduce time response. In this frame, the development of key components, their assembly and experimental investigation/ validation is on-going at Alenia Spazio-Laben/Business Unit Proel Tecnologie ( Proel in the following ) in the frame of an ESA GSTP program. The new components shall support different EP technologies, future EP multi-tasking capability and wide operating ranges. This paper reports about the development effort, its achievements and perspectives. 1. ABBREVIATIONS AND ACRONYMS BOL Beginning of Life CMBR Ceramic multilayer bender ring CTA Constant Temperature Anemometry. DUT Device under test EOL End of Life EP Electric Propulsion GEO Geosyncrhonous Earth Orbit GFCU Gas Flow Control Unit GIT Gridded ion thruster HET Hall Effect Thrusters LEO Low Earth Orbit LPC Low pressure capillary MEOP Maximum Expected Operating Pressure MFS Mass Flow rate Sensor NSSK North-South Station Keeping Pred Reduced pressure Ptank Tank pressure RMT Radiofrequency Magnetic Thruster RMTA Radiofrequency Magnetic Thruster Assembly ROOV Regulation and On-Off Valve SoW Statement of Work SPT Stationary Plasma Thruster.

  10. Coolant Design System for Liquid Propellant Aerospike Engines

    Science.gov (United States)

    McConnell, Miranda; Branam, Richard

    2015-11-01

    Liquid propellant rocket engines burn at incredibly high temperatures making it difficult to design an effective coolant system. These particular engines prove to be extremely useful by powering the rocket with a variable thrust that is ideal for space travel. When combined with aerospike engine nozzles, which provide maximum thrust efficiency, this class of rockets offers a promising future for rocketry. In order to troubleshoot the problems that high combustion chamber temperatures pose, this research took a computational approach to heat analysis. Chambers milled into the combustion chamber walls, lined by a copper cover, were tested for their efficiency in cooling the hot copper wall. Various aspect ratios and coolants were explored for the maximum wall temperature by developing our own MATLAB code. The code uses a nodal temperature analysis with conduction and convection equations and assumes no internal heat generation. This heat transfer research will show oxygen is a better coolant than water, and higher aspect ratios are less efficient at cooling. This project funded by NSF REU Grant 1358991.

  11. Synthesis and characterization of energetic thermoplastic elastomers for propellant formulations

    Directory of Open Access Journals (Sweden)

    Aparecida M. Kawamoto

    2009-01-01

    Full Text Available Synthesis and characterization of energetic ABA-type thermoplastic elastomers for propellant formulations has been carried out. Following the working plan elaborated, the synthesis and characterization of Poly 3- bromomethyl-3-methyl oxetane (PolyBrMMO, Poly 3- azidomethyl-3-methyl oxetane (PolyAMMO, Poly 3,3-bis-azidomethyl oxetane (PolyBAMO and Copolymer PolyBAMO/AMMO (by TDI end capping has been successfully performed. The thermoplastic elastomers (TPEs were synthesized using the chain elongation process PolyAMMO, GAP and PolyBAMO by diisocyanates. In this method 2.4-toluene diisocyanate (TDI is used to link block A (hard and mono- functional to B (soft and di-functional. For the hard A-block we used PolyBAMO and for the soft B-block we used PolyAMMO or GAP.This is a joint project set up, some years ago, between the Chemistry Division of the Institute of Aeronautics and Space (IAE - subordinated to the Brazilian Ministry of Defense - and the Fraunhofer Institut Chemische Technologie (ICT, in Germany. The products were characterized by different techniques as IR- and (1H,13CNMR spectroscopies, elemental and thermal analyses. New methodologies based on FT-IR analysis have been developed as an alternative for the determination of the molecular weight and CHNO content of the energetic polymers.

  12. Capturing self-propelled particles in a moving microwedge.

    Science.gov (United States)

    Kaiser, A; Popowa, K; Wensink, H H; Löwen, H

    2013-08-01

    Catching fish with a fishing net is typically done either by dragging a fishing net through quiescent water or by placing a stationary basket trap into a stream. We transfer these general concepts to micron-sized self-motile particles moving in a solvent at low Reynolds number and study their collective trapping behavior by means of computer simulations of a two-dimensional system of self-propelled rods. A chevron-shaped obstacle is dragged through the active suspension with a constant speed v and acts as a trapping "net." Three trapping states can be identified corresponding to no trapping, partial trapping, and complete trapping and their relative stability is studied as a function of the apex angle of the wedge, the swimmer density, and the drag speed v. When the net is dragged along the inner wedge, complete trapping is facilitated and a partially trapped state changes into a complete trapping state if the drag speed exceeds a certain value. Reversing the drag direction leads to a reentrant transition from no trapping to complete trapping and then back to no trapping upon increasing the drag speed along the outer wedge contour. The transition to complete trapping is marked by a templated self-assembly of rods forming polar smectic structures anchored onto the inner contour of the wedge. Our predictions can be verified in experiments of artificial or microbial swimmers confined in microfluidic trapping devices.

  13. Performance Analysis of NACA2420 as Wind Turbine Propeller Blade

    Directory of Open Access Journals (Sweden)

    Sulaeman Mustafa

    2017-03-01

    Full Text Available Wind is one of the popular renewable energy sources which is abundantly available either in land or at sea. The wind energy can be converted into electrical energy using wind turbines or wind energy conversion systems. However, the exploration and utilization of wind energy potential in Indonesia is not optimal yet. Therefore, in the present study, the performance of a NACA2420 airfoil as wind turbine blade is evaluated. The main objective of the present research is to determine the optimum angle of the propeller blade that can deliver the most optimum performance. In order to achieve the objectives, the wind turbine blade model was tested using a wind tunnel at wind speeds varying from 2 to 9 m/s. From this research, it is demonstrated that the tunnel has helped to increase the wind speed. The maximum wind speed was generated from the tunnel when the fan distance was 1.1 m. In addition, the experiment was also carried out by varying the pitch angles to be 00, 50, 80, 150, and 300. From the test measurements, it was found that the pitch angle of 50 produces the most optimal power which was at 221.039 watts with 0.401 of power coefficient.

  14. Design, Development and Validation of the Eurostar 3000 Large Propellant Tank

    Science.gov (United States)

    Autric, J.-M.; Catherall, D.; Figues, C.; Brockhoff, T.; Lafranconi, R.

    2004-10-01

    EADS Astrium has undertaken the design and development of an enlarged propellant tank for its high modular Eurostar 3000 telecom satellites platform. The design and development activities included fracture, stress and functional analysis, the manufacturing of development models for the propellant management device, the qualification of new manufacturing processes and the optimization of the design with respect to the main requirements. The successful design and development-testing phase has allowed starting the manufacturing of the qualification model.

  15. A thermovisco-hyperelastic constitutive model of HTPB propellant with damage at intermediate strain rates

    Science.gov (United States)

    Wang, Zhejun; Qiang, Hongfu; Wang, Tiejun; Wang, Guang; Hou, Xiao

    2017-08-01

    The uniaxial compressive tests at different temperatures (223-298 K) and strain rates ( 0.40-63 s^{-1}) are reported to study the properties of hydroxyl-terminated polybutadiene (HTPB) propellant at intermediate strain rates, using a new INSTRON testing machine. The experimental results indicate that the compressive properties (mechanical properties and damage) of HTPB propellant are remarkably affected by temperature and strain rate and display significant nonlinear material behaviors at large strains under all the test conditions. Continuously decreasing temperature and increasing strain rate, the characteristics of stress-strain curves and damage for HTPB propellant are more complex and are significantly different from that at room temperature or at lower strain rates. A new constitutive model was developed to describe the compressive behaviors of HTPB propellant at room temperature and intermediate strain rates by simply coupling the effect of strain rate into the conventional hyperelastic model. Based on the compressive behaviors of HTPB propellant and the nonlinear viscoelastic constitutive theories, a new thermovisco-hyperelastic constitutive model with damage was proposed to predict the stress responses of the propellant at low temperatures and intermediate strain rates. In this new model, the damage is related to the viscoelastic properties of the propellant. Meanwhile, the effect of temperature on the hyperelastic properties, viscoelastic properties and damage are all considered by the macroscopical method. The constitutive parameters in the proposed constitutive models were identified by the genetic algorithm (GA)-based optimization method. By comparing the predicted and experimental results, it can be found that the developed constitutive models can correctly describe the uniaxial compressive behaviors of HTPB propellant at intermediate strain rates and different temperatures.

  16. Current status of free radicals and electronically excited metastable species as high energy propellants

    Science.gov (United States)

    Rosen, G.

    1973-01-01

    A survey is presented of free radicals and electronically excited metastable species as high energy propellants for rocket engines. Nascent or atomic forms of diatomic gases are considered free radicals as well as the highly reactive diatomic triatomic molecules that posess unpaired electrons. Manufacturing and storage problems are described, and a review of current experimental work related to the manufacture of atomic hydrogen propellants is presented.

  17. Theory of intrachamber processes and design of solid-propellant rocket engines

    Science.gov (United States)

    Erokhin, Boris T.

    The theory of processes taking place inside the combustion chamber of solid-propellant rocket engines is presented, and methods of optimizing the design of such engines are discussed. In particular, attention is given to the selection of the solid propellant charge and igniters, volume density of the charge, structural and heat insulation materials, and thrust vector control devices. Examples of calculations of the nonstationary and quasi-stationary operating regimes and energy and mass characteristics are presented.

  18. Evaluation of Resuspension from Propeller Wash in Pearl Harbor and San Diego Bay

    Science.gov (United States)

    2014-07-01

    direction of the flow generated by the propeller. The body of the camera housing was parallel to the sea bottom, taking images of the laser “sheet...intensity histogram (RGB channel) for each image was adjusted in Adobe Photoshop ® to maximize contrast without distortion. The jpeg images were then...NOTES The original document contains color images . 14. ABSTRACT Propeller wash induces disturbances to the bottom sediment in Department of

  19. Feasibility study into a computational approach for marine propeller noise and cavitation modelling

    OpenAIRE

    Lidtke, Artur Konrad; Humphrey, Victor; Turnock, Stephen

    2015-01-01

    There is increased interest in the ability to predict the noise associated with commercial ship propellers. Key components of the computational analysis process are considered for two test cases and the future direction in resolving the associated challenges is presented. Firstly, the Potsdam Propeller Test Case is used to compute tonal blade passage noise using the Ffowcs Williams–Hawkings acoustic analogy. Cavitation extents predicted using the Sauer and Schnerr mass transfer model agree we...

  20. Parenting and Digital Media.

    Science.gov (United States)

    Coyne, Sarah M; Radesky, Jenny; Collier, Kevin M; Gentile, Douglas A; Linder, Jennifer Ruh; Nathanson, Amy I; Rasmussen, Eric E; Reich, Stephanie M; Rogers, Jean

    2017-11-01

    Understanding the family dynamic surrounding media use is crucial to our understanding of media effects, policy development, and the targeting of individuals and families for interventions to benefit child health and development. The Families, Parenting, and Media Workgroup reviewed the relevant research from the past few decades. We find that child characteristics, the parent-child relationship, parental mediation practices, and parents' own use of media all can influence children's media use, their attitudes regarding media, and the effects of media on children. However, gaps remain. First, more research is needed on best practices of parental mediation for both traditional and new media. Ideally, this research will involve large-scale, longitudinal studies that manage children from infancy to adulthood. Second, we need to better understand the relationship between parent media use and child media use and specifically how media may interfere with or strengthen parent-child relationships. Finally, longitudinal research on how developmental processes and individual child characteristics influence the intersection between media and family life is needed. The majority of children's media use takes place within a wider family dynamic. An understanding of this dynamic is crucial to understanding child media use as a whole. Copyright © 2017 by the American Academy of Pediatrics.

  1. On the combustion mechanisms of ZrH2 in double-base propellant.

    Science.gov (United States)

    Yang, Yanjing; Zhao, Fengqi; Yuan, Zhifeng; Wang, Ying; An, Ting; Chen, Xueli; Xuan, Chunlei; Zhang, Jiankan

    2017-12-13

    Metal hydrides are regarded as a series of promising hydrogen-supplying fuel for solid rocket propellants. Their effects on the energetic and combustion performances of propellants are closely related to their reaction mechanisms. Here we report a first attempt to determine the reaction mechanism of ZrH 2 , a high-density metal hydride, in the combustion of a double-base propellant to evaluate its potential as a fuel. ZrH 2 is determined to possess good resistance to oxidation by nitrocellulose and nitroglycerine. Thus its combustion starts with dehydrogenation to generate H 2 and metallic Zr. Subsequently, the newly formed Zr and H 2 participate in the combustion and, especially, Zr melts and then combusts on the burning surface which favors the heat feedback to the propellant. This phenomenon is completely different from the combustion behavior of the traditional fuel Al, where the Al particles are ejected off the burning surface of the propellant to get into the luminous flame zone to burn. The findings in this work validate the potential of ZrH 2 as a hydrogen-supplying fuel for double-base propellants.

  2. The steady performance prediction of propeller-rudder-bulb system based on potential iterative method

    International Nuclear Information System (INIS)

    Liu, Y B; Su, Y M; Ju, L; Huang, S L

    2012-01-01

    A new numerical method was developed for predicting the steady hydrodynamic performance of propeller-rudder-bulb system. In the calculation, the rudder and bulb was taken into account as a whole, the potential based surface panel method was applied both to propeller and rudder-bulb system. The interaction between propeller and rudder-bulb was taken into account by velocity potential iteration in which the influence of propeller rotation was considered by the average influence coefficient. In the influence coefficient computation, the singular value should be found and deleted. Numerical results showed that the method presented is effective for predicting the steady hydrodynamic performance of propeller-rudder system and propeller-rudder-bulb system. Comparing with the induced velocity iterative method, the method presented can save programming and calculation time. Changing dimensions, the principal parameter—bulb size that affect energy-saving effect was studied, the results show that the bulb on rudder have a optimal size at the design advance coefficient.

  3. Influence of Asymmetry and Driving Forces on the Propulsion of Bubble-Propelled Catalytic Micromotors

    Directory of Open Access Journals (Sweden)

    Masayuki Hayakawa

    2016-12-01

    Full Text Available Bubble-propelled catalytic micromotors have recently been attracting much attention. A bubble-propulsion mechanism has the advantage of producing a stronger force and higher speed than other mechanisms for catalytic micromotors, but the nature of the fluctuated bubble generation process affects the motions of the micromotors, making it difficult to control their motions. Thus, understanding of the influence of fluctuating bubble propulsion on the motions of catalytic micromotors is important in exploiting the advantages of bubble-propelled micromotors. Here, we report experimental demonstrations of the bubble-propelled motions of propeller-shaped micromotors and numerical analyses of the influence of fluctuating bubble propulsion on the motions of propeller-shaped micromotors. We found that motions such as trochoid-like motion and circular motion emerged depending on the magnitude or symmetricity of fluctuations in the bubble-propulsion process. We hope that those results will help in the construction and application of sophisticated bubble-propelled micromotors in the future.

  4. Development of a miniature solid propellant rocket motor for use in plume simulation studies

    Science.gov (United States)

    Baran, W. J.

    1974-01-01

    A miniature solid propellant rocket motor has been developed to be used in a program to determine those parameters which must be duplicated in a cold gas flow to produce aerodynamic effects on an experimental model similar to those produced by hot, particle-laden exhaust plumes. Phenomena encountered during the testing of the miniature solid propellant motors included erosive propellant burning caused by high flow velocities parallel to the propellant surface, regressive propellant burning as a result of exposed propellant edges, the deposition of aluminum oxide on the nozzle surfaces sufficient to cause aerodynamic nozzle throat geometry changes, and thermal erosion of the nozzle throat at high chamber pressures. A series of tests was conducted to establish the stability of the rocket chamber pressure and the repeatibility of test conditions. Data are presented which define the tests selected to represent the final test matrix. Qualitative observations are also presented concerning the phenomena experienced based on the results of a large number or rocket tests not directly applicable to the final test matrix.

  5. Collective behavior of penetrable self-propelled rods in two dimensions

    Science.gov (United States)

    Abkenar, Masoud; Marx, Kristian; Auth, Thorsten; Gompper, Gerhard

    2013-12-01

    Collective behavior of self-propelled particles is observed on a microscale for swimmers such as sperm and bacteria as well as for protein filaments in motility assays. The properties of such systems depend both on their dimensionality and the interactions between their particles. We introduce a model for self-propelled rods in two dimensions that interact via a separation-shifted Lennard-Jones potential. Due to the finite potential barrier, the rods are able to cross. This model allows us to efficiently simulate systems of self-propelled rods that effectively move in two dimensions but can occasionally escape to the third dimension in order to pass each other. Our quasi-two-dimensional self-propelled particles describe a class of active systems that encompasses microswimmers close to a wall and filaments propelled on a substrate. Using Monte Carlo simulations, we first determine the isotropic-nematic transition for passive rods. Using Brownian dynamics simulations, we characterize cluster formation of self-propelled rods as a function of propulsion strength, noise, and energy barrier. Contrary to rods with an infinite potential barrier, an increase of the propulsion strength does not only favor alignment but also effectively decreases the potential barrier that prevents crossing of rods. We thus find a clustering window with a maximum cluster size at medium propulsion strengths.

  6. Formulation development and characterization of cellulose acetate nitrate based propellants for improved insensitive munitions properties

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2014-06-01

    Full Text Available Cellulose acetate nitrate (CAN was used as an insensitive energetic binder to improve the insensitive munitions (IM properties of gun propellants to replace the M1 propellant used in 105 mm artillery charges. CAN contains the energetic nitro groups found in nitrocellulose (NC, but also acetyl functionalities, which lowered the polymer's sensitivity to heat and shock, and therefore improved its IM properties relative to NC. The formulation, development and small-scale characterization testing of several CAN-based propellants were done. The formulations, using insensitive energetic solid fillers and high-nitrogen modifiers in place of nitramine were completed. The small scale characterization testing, such as closed bomb testing, small scale sensitivity, thermal stability, and chemical compatibility were done. The mechanical response of the propellants under high-rate uni-axial compression at, hot, cold, and ambient temperatures were also completed. Critical diameter testing, hot fragment conductive ignition (HFCI tests were done to evaluate the propellants' responses to thermal and shock stimuli. Utilizing the propellant chemical composition, theoretical predictions of erosivity were completed. All the small scale test results were utilized to down-select the promising CAN based formulations for large scale demonstration testing such as the ballistic performance and fragment impact testing in the 105 mm M67 artillery charge configurations. The test results completed in the small and large scale testing are discussed.

  7. IMPACT OF SOME GEOMETRICAL ASPECTS ON THE TANDEM CO-ROTATING PROPELLER HYDRODYNAMIC CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Boucetta Djahida

    2017-01-01

    Full Text Available In the present paper, a numerical simulation based on Kω-SST turbulence model has been carried out to determine the tandem propeller hydrodynamic characteristics in non-cavitating viscous flow by using the commercial code Fluent. As the first step, the numerical approach has been applied to the case of single propeller and the comparison with experiment results was in a good agreement. Next, the effects of axial and angular displacement as well as the diameter ratio between the tandem propellers have been investigated. This part of the study reveals that the tandem with idem propeller diameters is strongly recommended to assure more advantages. Furthermore, the tandem geometry corresponding to the axial displacement equal to 0.6D seems to be the best configuration and the open water performances remain almost unchanged with the variation of angular displacement. On the other hand, details of the mutual interaction between tandem propellers were also given by showing pressure contours, streamlines and thrust coefficient. Globally, this study illustrates the advantages of replacing single propellers by tandem solution.

  8. Fuels and Space Propellants for Reusable Launch Vehicles: A Small Business Innovation Research Topic and Its Commercial Vision

    Science.gov (United States)

    Palaszewski, Bryan A.

    1997-01-01

    Under its Small Business Innovation Research (SBIR) program (and with NASA Headquarters support), the NASA Lewis Research Center has initiated a topic entitled "Fuels and Space Propellants for Reusable Launch Vehicles." The aim of this project would be to assist in demonstrating and then commercializing new rocket propellants that are safer and more environmentally sound and that make space operations easier. Soon it will be possible to commercialize many new propellants and their related component technologies because of the large investments being made throughout the Government in rocket propellants and the technologies for using them. This article discusses the commercial vision for these fuels and propellants, the potential for these propellants to reduce space access costs, the options for commercial development, and the benefits to nonaerospace industries. This SBIR topic is designed to foster the development of propellants that provide improved safety, less environmental impact, higher density, higher I(sub sp), and simpler vehicle operations. In the development of aeronautics and space technology, there have been limits to vehicle performance imposed by traditionally used propellants and fuels. Increases in performance are possible with either increased propellant specific impulse, increased density, or both. Flight system safety will also be increased by the use of denser, more viscous propellants and fuels.

  9. Mass Media: The Invisible Environment.

    Science.gov (United States)

    Glessing, Robert J.; White, William P.

    This anthology for students of media consists of essays and articles grouped under four topics: media forms, media content, media environments, and "the last word." Media forms deals with the nature of these kinds of media: electronic, print, film, music, and comics, graffiti, and clothing. Media content contains articles on the news, advertising,…

  10. Media Pluralism and Diversity

    DEFF Research Database (Denmark)

    In the western world, a diverse and pluralistic media landscape is deemed essential for democracy. But how universal is media pluralism as a concept underpinning media policies? To what extent do normative approaches, regulatory dimensions and monitoring systems differ throughout the world...... challenges for media pluralism policies in the light of a fast changing media environment. The book is unique in that it confronts insights from all parts of the world and from a broad range of disciplines including law, economics, media studies, and sociology....

  11. Social Media Reputation

    DEFF Research Database (Denmark)

    Etter, Michael Andreas; Ravasi, Davide; Colleoni, Elanor

    Social media enable millions of users to create and disseminate narratives about organizations that increase their public exposure and shape public perceptions. In this paper, we draw on the sociology of news production and research on computer-mediated communication to discuss how different...... motivational drivers and contextual conditions associated with the formation of narratives in traditional news media and social media influence their content, diffusion, and impact significantly. Our analysis suggests that current theories of media reputation may provide an incomplete representation...... of the phenomenon, and highlight theoretically relevant differences and interrelationships between reputational dynamics involving news media and social media....

  12. Social Media Reputation

    DEFF Research Database (Denmark)

    Etter, Michael Andreas; Ravasi, Davide; Colleoni, Elanor

    motivational drivers and contextual conditions associated with the formation of narratives in traditional news media and social media influence their content, diffusion, and impact significantly. Our analysis suggests that current theories of media reputation may provide an incomplete representation......Social media enable millions of users to create and disseminate narratives about organizations that increase their public exposure and shape public perceptions. In this paper, we draw on the sociology of news production and research on computer-mediated communication to discuss how different...... of the phenomenon, and highlight theoretically relevant differences and interrelationships between reputational dynamics involving news media and social media....

  13. AMAMM - All Media Are Mixed Media

    DEFF Research Database (Denmark)

    All Media Are Mixed Media Alle medier er blandingsmedier. Alle kunstarter er kompositte. Alle sanser er sammensatte. Alle medialiteter er miksede og mangfoldige. Alle er AMAMM. Denne påstand står centralt i ord-, billed- og medie-teoretikeren W.J.T. Mitchells forfatterskab. I hosstående bog tager...

  14. Learning Media Programme

    NARCIS (Netherlands)

    Westera, Wim

    2009-01-01

    Westera, W. (2009). Learning Media Programme. Introductory presentation of Learning Media Programme for visitors of Kavala University of Technology, Kavala, Greece and National Institute of Multimedia Education, Chiba, Japan. March, 2, 2009, Heerlen, The Netherlands.

  15. Development of contrast media

    International Nuclear Information System (INIS)

    Krause, W.

    1993-01-01

    Description of all contrast media (ionic and nonionic monomers, ionic and nonionic dimers) was presented. Chemotoxicity, osmolality and viscosity of some contrast agents were analyzed. The main adverse reactions to ionic and nonionic contrast media were described

  16. Media and Crime

    DEFF Research Database (Denmark)

    Agger, Gunhild; Waade, Anne Marit

    2011-01-01

    Recent developments in the relationship between media and crime are analyzed, taking both fiction and journalism in account......Recent developments in the relationship between media and crime are analyzed, taking both fiction and journalism in account...

  17. MODERN MEDIA EDUCATION MODELS

    Directory of Open Access Journals (Sweden)

    Alexander Fedorov

    2011-03-01

    Full Text Available The author supposed that media education models can be divided into the following groups:- educational-information models (the study of the theory, history, language of media culture, etc., based on the cultural, aesthetic, semiotic, socio-cultural theories of media education;- educational-ethical models (the study of moral, religions, philosophical problems relying on the ethic, religious, ideological, ecological, protectionist theories of media education;- pragmatic models (practical media technology training, based on the uses and gratifications and ‘practical’ theories of media education;- aesthetical models (aimed above all at the development of the artistic taste and enriching the skills of analysis of the best media culture examples. Relies on the aesthetical (art and cultural studies theory; - socio-cultural models (socio-cultural development of a creative personality as to the perception, imagination, visual memory, interpretation analysis, autonomic critical thinking, relying on the cultural studies, semiotic, ethic models of media education.

  18. Trends in media use.

    Science.gov (United States)

    Roberts, Donald F; Foehr, Ulla G

    2008-01-01

    American youth are awash in media. They have television sets in their bedrooms, personal computers in their family rooms, and digital music players and cell phones in their backpacks. They spend more time with media than any single activity other than sleeping, with the average American eight- to eighteen-year-old reporting more than six hours of daily media use. The growing phenomenon of "media multitasking"--using several media concurrently--multiplies that figure to eight and a half hours of media exposure daily. Donald Roberts and Ulla Foehr examine how both media use and media exposure vary with demographic factors such as age, race and ethnicity, and household socioeconomic status, and with psychosocial variables such as academic performance and personal adjustment. They note that media exposure begins early, increases until children begin school, drops off briefly, then climbs again to peak at almost eight hours daily among eleven- and twelve-year-olds. Television and video exposure is particularly high among African American youth. Media exposure is negatively related to indicators of socioeconomic status, but that relationship may be diminishing. Media exposure is positively related to risk-taking behaviors and is negatively related to personal adjustment and school performance. Roberts and Foehr also review evidence pointing to the existence of a digital divide--variations in access to personal computers and allied technologies by socioeconomic status and by race and ethnicity. The authors also examine how the recent emergence of digital media such as personal computers, video game consoles, and portable music players, as well as the media multitasking phenomenon they facilitate, has increased young people's exposure to media messages while leaving media use time largely unchanged. Newer media, they point out, are not displacing older media but are being used in concert with them. The authors note which young people are more or less likely to use several

  19. Advertising on social media

    OpenAIRE

    Sumit Goyal

    2013-01-01

    This communication reports the latest trends of advertising on social media. Social media advertising means to gain traffic or attention of online users through social media sites. Today, when a user thinks about buying something, he first comes to the internet, searches for that product, compares its price with other competing brands and takes a decision, which one to buy. In this write-up, author has discussed many aspects concerning advertising through social media, viz., what is social me...

  20. Asian Media Productions

    DEFF Research Database (Denmark)

    This work consists of 12 essays on different aspects of Asian media by Japanese, European, and American scholars, many of whom have themselves been involved in the production of media forms. Working in the fields of anthropology, media and cultural studies, and on the basis of hands-on research......, they have written a book on the social practices and cultural attitudes of people producing, reading, watching and listening to different kinds of media in Japan, China, Taiwan, Indonesia, Vietnam, Singapore and India....

  1. Oriented Fiber Filter Media

    OpenAIRE

    R. Bharadwaj; A. Patel, S. Chokdeepanich, Ph.D.; G.G. Chase, Ph.D.

    2008-01-01

    Coalescing filters are widely used throughout industry and improved performance will reduce droplet emissions and operating costs. Experimental observations show orientation of micro fibers in filter media effect the permeability and the separation efficiency of the filter media. In this work two methods are used to align the fibers to alter the filter structure. The results show that axially aligned fiber media improve quality factor on the order of 20% and cutting media on an angle from a t...

  2. School Media Specialist Certification.

    Science.gov (United States)

    Bender, David R.

    The American Association of School Librarians (AASL) supports the development by media specialists of the competencies and skills they need, whether derived from training in general and professional education, or from media specialization. The "Certification Model for Professional School Media Personnel," developed and designed by an…

  3. Asian Media Productions

    DEFF Research Database (Denmark)

    This work consists of 12 essays on different aspects of Asian media by Japanese, European, and American scholars, many of whom have themselves been involved in the production of media forms. Working in the fields of anthropology, media and cultural studies, and on the basis of hands-on research...

  4. Sizing Up Social Media

    Science.gov (United States)

    Pearson, Jerold

    2010-01-01

    Most people are aware of the increasing importance of social media to institutional advancement, and many colleges and universities have started investing resources in these media. The next step is to measure the impact of social media on the institution and evaluate the success of one's efforts. Every advancement leader should understand how…

  5. Planning Instructional Media

    Science.gov (United States)

    Clark, Richard E.

    1972-01-01

    Reviews the developments in communications and educational psychology that have influenced present educational media strategies and shows how recent breakthroughs in learning theory and media research offer a new direction in the design and use of instructional media. (Author/JM)

  6. Media in Corporate Training.

    Science.gov (United States)

    Vaughan, Ted W.

    1981-01-01

    Reports the results of a survey on the design, development, production, and utilization of media in business training programs. In-house production is described, as well as the types of media most used by corporations, problems with outside vendors, and future directions of media development. (BK)

  7. Youth Media and Agency

    Science.gov (United States)

    Hauge, Chelsey

    2014-01-01

    This article addresses how capacity is conceived of and understood in youth media/civic education programming, and how beliefs about agency, development, relationality and youth manifests in the discourses, programmes, and practices of organizations operating youth media programmes. Through attention to a youth media and development programme in…

  8. Media, Minds, and Masses.

    Science.gov (United States)

    Baggot, James; Vino, Faith

    This booklet describes the language arts course "Media, Minds, and Masses," written for the Dade County, Fla., public schools. Topics for the course include the workings of contemporary radio, television, newspapers, magazines, and movies; the present status and power of media; the history and development of media; and the influences of…

  9. Managing Media Workers

    NARCIS (Netherlands)

    Deuze, M.; Lowe, G.F.; Brown, C.

    2015-01-01

    People are more involved with media than ever but news about media as an industry is less than optimistic. The number of people across the creative industries who are losing jobs illustrates all too well. Media managers seem at a loss in developing survival strategies, and specifically in organizing

  10. Social Media Empowerment (I)

    NARCIS (Netherlands)

    A. Cox

    2011-01-01

    full text via link. Social media stellen mensen, merken en bedrijven in staat om zichzelf te versterken. Soms wordt optimaal gebruik gemaakt van Social Media Empowerment, maar soms ook wat minder. Effectief inzetten van social media. Regel 1: Start met context en motivatie

  11. Youth media lifestyles

    NARCIS (Netherlands)

    van Kruistum, Claudia; Leseman, Paul Pm; de Haan, Mariëtte

    2014-01-01

    In this article, the concept of "media lifestyles" is adopted in order to develop a comprehensive approach toward youth engagement in communication media. We explore how 503 Dutch eighth grade students with full access to new technology combine a broad range of media by focusing on their engagement

  12. Konvergensi Media Periklanan dalam Konstelasi Perkembangan Teknologi Media

    Directory of Open Access Journals (Sweden)

    Widodo Agus Setianto

    2008-11-01

    Full Text Available The recent development of information technology and commuitication with the presence of new media has affected human behaviors and habit especially in media consumption patterns. Efforts should be made by the conventional mass media, as advertising media, to be in line with the new media development. This article argues that the form of advertising media in the new media environment will be convergence media advertising.

  13. Calculation for Primary Combustion Characteristics of Boron-Based Fuel-Rich Propellant Based on BP Neural Network

    OpenAIRE

    Wan'e, Wu; Zuoming, Zhu

    2012-01-01

    A practical scheme for selecting characterization parameters of boron-based fuel-rich propellant formulation was put forward; a calculation model for primary combustion characteristics of boron-based fuel-rich propellant based on backpropagation neural network was established, validated, and then was used to predict primary combustion characteristics of boron-based fuel-rich propellant. The results show that the calculation error of burning rate is less than ± 7 . 3 %; in the formulation rang...

  14. Noise of a model high speed counterrotation propeller at simulated takeoff/approach conditions (F7/A7)

    Science.gov (United States)

    Woodward, Richard P.

    1987-01-01

    A high speed advanced counterrotation propeller, was tested in the NASA-Lewis 9 x 15 foot Anechoic Wind Tunnel at simulated takeoff/approach conditions of 0.2 Mach number. Acoustic measurements were taken with fixed floor microphones, an axially translating microphone probe, and with a polar microphone probe which was fixed to the propeller nacelle and could take both sideline and circumferential acoustic surveys. Aerodynamic measurements were also made to establish the propeller operating conditions. The propeller was run over a range of blade setting angles from 36.4/36.5 to 41.1/39.4 deg, tip speeds from 165 to 259 m/sec, rotor spacings from 1.56 to 3.63 based on forward rotor tip chord to aerodynamic separation, and angles of attack to + or - 16 deg. First order rotor alone tones showed highest directivity levels near the propeller plane, while interaction tone showed high levels throughout sideline directivity, especially toward the propeller rotation axis. Interaction tone levels were sensitive to propeller row spacing while rotor alone tones showed little spacing effect. There is a decreased noise level associated with higher propeller blade numbers for the same overall propeller thrust.

  15. Numerical analysis of the effect of plasma flow control on enhancing the aerodynamic characteristics of stratospheric screw propeller

    International Nuclear Information System (INIS)

    Cheng Yufeng; Nie Wansheng

    2012-01-01

    Based on the body force aerodynamic actuation mechanism of dielectric barrier discharge (DBD) plasma, the effect of plasma flow control on enhancing the aerodynamic characteristics of ten blade elements equably along the stratospheric screw propeller blade was numerical studied. Then the effect of plasma flow control enhancing the aerodynamic characteristics of stratospheric screw propeller was compared that by the blade element theory method. The results show that the flow separate phenomena will easily happen in the root region and top end region of screw propeller, and the blade elements in the root region of screw propeller may work on the negative attack angle condition. DBD plasma flow control can entirely restrain the faintish flow separate phenomena in middle region of screw propeller. Although DBD plasma flow control can not entirely restrain the badly flow separate phenomena in top end region of screw propeller, it also can enhance the aerodynamic characteristics of blade elements in these regions in same degree. But effect of DBD plasma flow control on enhancing the aerodynamic characteristics of the blade elements working on the negative attack angle condition is ineffectively. It can be concluded that DBD plasma flow control can enhance the aerodynamic characteristics of stratospheric screw propeller, the thrust of the whole propeller and the propeller efficiency in the case of plasma on will increases by a factor of 28.27% and 12.3% respectively compared with that in the case of plasma off studied. (authors)

  16. Numerical Analysis of the Unsteady Propeller Performance in the Ship Wake Modified By Different Wake Improvement Devices

    Directory of Open Access Journals (Sweden)

    Bugalski Tomasz

    2014-10-01

    Full Text Available The paper presents the summary of results of the numerical analysis of the unsteady propeller performance in the non-uniform ship wake modified by the different wake improvement devices. This analysis is performed using the lifting surface program DUNCAN for unsteady propeller analysis. Te object of the analysis is a 7000 ton chemical tanker, for which four different types of the wake improvement devices have been designed: two vortex generators, a pre-swirl stator, and a boundary layer alignment device. These produced five different cases of the ship wake structure: the original hull and hull equipped alternatively with four wake improvement devices. Two different propellers were analyzed in these five wake fields, one being the original reference propeller P0 and the other - a specially designed, optimized propeller P3. Te analyzed parameters were the pictures of unsteady cavitation on propeller blades, harmonics of pressure pulses generated by the cavitating propellers in the selected points and the fluctuating bearing forces on the propeller shaft. Some of the calculated cavitation phenomena were confronted with the experimental. Te objective of the calculations was to demonstrate the differences in the calculated unsteady propeller performance resulting from the application of different wake improvement devices. Te analysis and discussion of the results, together with the appropriate conclusions, are included in the paper.

  17. The Media Mixer

    DEFF Research Database (Denmark)

    Vestergaard, Vitus; Mortensen, Christian Hviid

    works; works that are based on already existing works. This cultural practice thrives throughout the Internet, most notably on web2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here...... domains is bridged, and it is our intention that the users learn about media through a creative process where the border between creating, playing and learning is blurred. There are many challenges in evolving a museum based on analogue print media to an interactive and participatory site but we suggest...

  18. Notes for media reinvention

    Directory of Open Access Journals (Sweden)

    Jesús Miguel Flores-Vivar

    2009-10-01

    Full Text Available Journalism and media are going through a change of era. This change is reflected in the transformation of journalism and media-lived and that another major in 1980 that became known as mediamorphosis, by this, professionals have to learn new roles. The impact of information technology and Internet has changed the way how you present the news and, most importantly, transform the business model that has characterized media companies. This article analyzes the current situation provides some strategic guidelines to be followed by some media-and-do and studied some of the new profiles arebeginning to emerge as a result of the reinvention of journalism and the media.

  19. Compressive mechanical properties of HTPB propellant at low temperatures and high strain rates

    Directory of Open Access Journals (Sweden)

    Xiangdong Chen

    Full Text Available To study the compressive mechanical properties of the hydroxyl-terminated polybutadiene (HTPB propellant at high strain rates (700–1900/s and low temperatures (−50 °C to 25 °C, we conducted a dynamic mechanical experiment using cylindrical specimens on a split Hopkinson pressure bar (SHPB. In addition, scanning electron microscopy was employed to observe the compressive fracture surfaces. The experimental results indicate the effectiveness of the proposed SHPB testing for the HTPB propellant. The effects of the strain rate and low temperature remarkably influenced the variations in stress. The lower temperatures and higher the strain rate generated an obvious increase in the modulus and compressive strength. Even at −50 °C and 1900/s, the propellant still maintained its viscoelastic characteristics. On the basis of the time–temperature equivalence principle, we obtained the master curves of the mechanical parameters. The propellant mainly exhibited transgranular fracture damage, increased porosity, and matrix tearing after impact. Keywords: HTPB propellant, Dynamic mechanical properties, Low temperatures, High strain rates

  20. An SEM and EDS study of the microstructure of nitrate ester plasticized polyether propellants

    Directory of Open Access Journals (Sweden)

    YONG LIU

    2010-03-01

    Full Text Available To probe the microstructures of nitrate ester plasticized polyether (NEPE composite propellants and observe the morphology of each constitute in the propellant, the microstructure and elemental constitutes of NEPE propellants were investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. The ammonium perchlorate (AP grains had a scraggy surface and were difficult to disperse uniformly. The compatibility between the AP grains and the polymer binder was poor, especially for large grains. The size distribution range of the AP and octogen (HMX grains in propellants varied from several to several hundreds μm for the former while for the latter from several to several tens μm. Contrasting images before and after dissolution the propellant in trichloromethane showed that the degree of crosslinking of the polymer binder was low since non-crosslinked binder on the surface areas was easily removed by the solvent, and that the plasticizer was near the HMX grains and contributed more O to the element analysis of HMX.

  1. Vent System Analysis for the Cryogenic Propellant Storage Transfer Ground Test Article

    Science.gov (United States)

    Hedayat, A

    2013-01-01

    To test and validate key capabilities and technologies required for future exploration elements such as large cryogenic propulsion stages and propellant depots, NASA is leading the efforts to develop and design the Cryogenic Propellant Storage and Transfer (CPST) Cryogenic Fluid Management (CFM) payload. The primary objectives of CPST payload are to demonstrate: 1) in-space storage of cryogenic propellants for long duration applications; and 2) in-space transfer of cryogenic propellants. The Ground Test Article (GTA) is a technology development version of the CPST payload. The GTA consists of flight-sized and flight-like storage and transfer tanks, liquid acquisition devices, transfer, and pressurization systems with all of the CPST functionality. The GTA is designed to perform integrated passive and active thermal storage and transfer performance testing with liquid hydrogen (LH2) in a vacuum environment. The GTA storage tank is designed to store liquid hydrogen and the transfer tank is designed to be 5% of the storage tank volume. The LH2 transfer subsystem is designed to transfer propellant from one tank to the other utilizing pressure or a pump. The LH2 vent subsystem is designed to prevent over-pressurization of the storage and transfer tanks. An in-house general-purpose computer program was utilized to model and simulate the vent subsystem operation. The modeling, analysis, and the results will be presented in the final paper.

  2. Exploring the Dynamics of Propeller Loops in Human Telomeric DNA Quadruplexes Using Atomistic Simulations

    Science.gov (United States)

    2017-01-01

    We have carried out a series of extended unbiased molecular dynamics (MD) simulations (up to 10 μs long, ∼162 μs in total) complemented by replica-exchange with the collective variable tempering (RECT) approach for several human telomeric DNA G-quadruplex (GQ) topologies with TTA propeller loops. We used different AMBER DNA force-field variants and also processed simulations by Markov State Model (MSM) analysis. The slow conformational transitions in the propeller loops took place on a scale of a few μs, emphasizing the need for long simulations in studies of GQ dynamics. The propeller loops sampled similar ensembles for all GQ topologies and for all force-field dihedral-potential variants. The outcomes of standard and RECT simulations were consistent and captured similar spectrum of loop conformations. However, the most common crystallographic loop conformation was very unstable with all force-field versions. Although the loss of canonical γ-trans state of the first propeller loop nucleotide could be related to the indispensable bsc0 α/γ dihedral potential, even supporting this particular dihedral by a bias was insufficient to populate the experimentally dominant loop conformation. In conclusion, while our simulations were capable of providing a reasonable albeit not converged sampling of the TTA propeller loop conformational space, the force-field description still remained far from satisfactory. PMID:28475322

  3. Dynamic strain measurements of marine propellers under non-uniform inflow

    Science.gov (United States)

    Tian, Jin; Croaker, Paul; Zhang, Zhiyi; Hua, Hongxing

    2016-09-01

    An experimental investigation was conducted to determine the dynamic strain characteristics of marine propellers under non-uniform inflow. Two 7-bladed highly skewed model propellers of identical geometries, but different elastic characteristics were tested at various rotational speeds and free stream velocities in the water tunnel. Two kinds of wire mesh wake screens located 400mm upstream of the propeller plane were used to generate four-cycle and six-cycle inflows. A laser doppler velocimetry (LDV) system located 100mm downstream of the wake screen plane was used to measure the axial velocity distributions produced by the wake screens. Strain gauges were bonded onto the propeller blades in different positions. A customized underwater data acquisition system which can record data off-line was used to record the dynamic strain. The results show that the frequency properties of the blade dynamic strain are determined by the harmonics of the inflow and that the stiffness of the propeller has an essential effect on the dynamic strain amplitudes.

  4. Numerical prediction analysis of propeller bearing force for full-scale hull–propeller–rudder system

    Directory of Open Access Journals (Sweden)

    Chao Wang

    2016-11-01

    Full Text Available The hybrid grid was adopted and numerical prediction analysis of propeller unsteady bearing force considering free surface was performed for mode and full-scale KCS hull–propeller–rudder system by employing RANS method and VOF model. In order to obtain the propeller velocity under self-propulsion point, firstly, the numerical simulation for self-propulsion test of full-scale ship is carried out. The results show that the scale effect of velocity at self-propulsion point and wake fraction is obvious. Then, the transient two-phase flow calculations are performed for model and full-scale KCS hull–propeller–rudder systems. According to the monitoring data, it is found that the propeller unsteady bearing force is fluctuating periodically over time and full-scale propeller's time-average value is smaller than model-scale's. The frequency spectrum curves are also provided after fast Fourier transform. By analyzing the frequency spectrum data, it is easy to summarize that each component of the propeller bearing force have the same fluctuation frequency and the peak in BFP is maximum. What's more, each component of full-scale bearing force's fluctuation value is bigger than model-scale's except the bending moment coefficient about the Y-axis.

  5. Risk assessment during operating self-propelled lifting jib cranes in conditions of insufficient information

    Directory of Open Access Journals (Sweden)

    Lagerev A.V.

    2017-06-01

    Full Text Available Presents the results of statistical analyses identified by the expert diagnostics of defects of the self-propelled lifting jib cranes, spent a normative term of exploitation. The greatest number of defects associated with the destruction and dete-rioration of structural elements, the occurrence of fatigue cracks and a violation of the conditions of operation of the equipment. The greatest number of defects occurs in the hydraulic system of cranes, the rope-block system, and rarely in steel structures. To conduct risk analysis of self-propelled jib cranes in case of insufficient information, proposed the method of expert estimations. It allows to assess the impact of potential defects on self-propelled jib cranes on the value of the economic damage of the crane and moving cargo and the value of the traumatic exposure on men. The proposed list of possible defects self-propelled lifting jib cranes and a checklist of questions about the degree of influence of these defects. Proposed calculated dependences to the approximate calculation of the magnitude of technical risk in the opera-tion of self-propelled jib cranes. The results of statistical analysis of expert estimations for each possible defect and per-formed their ranking in terms of impact on the magnitude of the economic damage of the crane and moving loads, the value of the traumatic exposure. Was calculated the value of technical risk for the surveyed taps.

  6. Small Propeller and Rotor Testing Capabilities of the NASA Langley Low Speed Aeroacoustic Wind Tunnel

    Science.gov (United States)

    Zawodny, Nikolas S.; Haskin, Henry H.

    2017-01-01

    The Low Speed Aeroacoustic Wind Tunnel (LSAWT) at NASA Langley Research Center has recently undergone a configuration change. This change incorporates an inlet nozzle extension meant to serve the dual purposes of achieving lower free-stream velocities as well as a larger core flow region. The LSAWT, part of the NASA Langley Jet Noise Laboratory, had historically been utilized to simulate realistic forward flight conditions of commercial and military aircraft engines in an anechoic environment. The facility was modified starting in 2016 in order to expand its capabilities for the aerodynamic and acoustic testing of small propeller and unmanned aircraft system (UAS) rotor configurations. This paper describes the modifications made to the facility, its current aerodynamic and acoustic capabilities, the propeller and UAS rotor-vehicle configurations to be tested, and some preliminary predictions and experimental data for isolated propeller and UAS rotor con figurations, respectively. Isolated propeller simulations have been performed spanning a range of advance ratios to identify the theoretical propeller operational limits of the LSAWT. Performance and acoustic measurements of an isolated UAS rotor in hover conditions are found to compare favorably with previously measured data in an anechoic chamber and blade element-based acoustic predictions.

  7. Project Minerva: A low cost manned Mars mission based on indigenous propellant production

    Science.gov (United States)

    Beder, David; Bryan, Richard; Bui, Tuyen; Caviezel, Kelly; Cinnamon, Mark; Daggert, Todd; Folkers, Mike; Fornia, Mark; Hanks, Natasha; Hamilton, Steve

    1992-06-01

    Project Minerva is a low-cost manned Mars mission designed to deliver a crew of four to the Martian surface using only two sets of two launches from the Kennedy Space Center. Key concepts which make this mission realizable are the use of near-term technologies and in-situ propellant production, following the scenario originally proposed by R. Zubrin. The first set of launches delivers two unmanned payloads into low Earth orbit (LEO): the first payload consists of an Earth Return Vehicle (ERV), a propellant production plant, and a set of robotic vehicles; the second payload consists of the trans-Mars injection (TMI) upper stage. In LEO, the two payloads are docked and the configuration is injected into a Mars transfer orbit. The landing on Mars is performed with the aid of multiple aerobraking maneuvers. On the Martian surface, the propellant production plant uses a Sabatier/electrolysis type process to combine nine tons of hydrogen with carbon dioxide from the Martian atmosphere to produce over a hundred tons of liquid oxygen and liquid methane, which are later used as the propellants for the rover expeditions and the manned return journey of the ERV. The systems necessary for the flights to and from Mars, as well as those needed for the stay on Mars, are discussed. These systems include the transfer vehicle design, life support, guidance and communications, rovers and telepresence, power generation, and propellant manufacturing. Also included are the orbital mechanics, the scientific goals, and the estimated mission costs.

  8. Numerical Simulations Of Hydrodynamic Open-Water Characteristics Of A Ship Propeller

    Directory of Open Access Journals (Sweden)

    Felicjancik Judyta

    2016-12-01

    Full Text Available The paper presents the results of numerical simulations of ship propeller operation bearing the name of Propeller Open Water (POW Tests. The object of tests was a sample ship propeller (PPTC1, the geometrical and kinematic data of which are available, along with the results of model tests, on the official page of the research centre involved in the measurements. The research aimed at verifying the correctness of results of numerical simulations performed in the model and real scale. The results of numerical analyses performed in the model scale were confronted with those measured in the experiment. Then, making use of dimensionless coefficients which characterise propeller’s operation, the recorded model data were extrapolated to real conditions and compared with corresponding results of simulations. Both the numerical simulations and the experimental research were performed for the same propeller load states. The reported research is in line with other activities which aim at developing advanced numerical methods to support the process of ship propeller designing.

  9. Design of a new VTOL UAV by combining cycloidal blades and FanWing propellers

    Science.gov (United States)

    Li, Daizong

    Though the propelling principles of Cycloidal Blades and FanWing propellers are totally different, their structures are similar. Therefore, it is possible to develop an aircraft which combines both types of the propulsion modes of Cyclogyro and FanWing aircrafts. For this kind of aircraft, Cycloidal Blades Mode provides capabilities of Vertical Take-Off and Landing, Instantly Alterable Vector Thrusting, and Low Noise. The FanWing Mode provides capabilities of High Efficiency, Energy-Saving, and Cannot-Stall Low-Speed Cruising. Besides, because both of these propellers are observably better than conventional screw propeller in terms of efficiency, so this type of VTOL UAV could fly with Long Endurance. Furthermore, the usage of flying-wing takes advantage of high structure utilization and high aerodynamic efficiency, eliminates the interference of fuselage and tail, and overcomes flying wing's shortcomings of pitching direction instability and difficulty of control. A new magnetic suspension track-type cycloidal propulsion system is also presented in the paper to solve problems of heavy structure, high mechanical resistance, and low reliability in the traditional cycloidal propellers. The further purpose of this design is to trying to make long-endurance VTOL aircraft and Practical Flying Cars possible in reality, and to bring a new era to the aviation industry.

  10. Comprehension of digital media

    International Nuclear Information System (INIS)

    Kim, Ju Hwan

    2008-11-01

    This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

  11. Radiographic contrast media

    International Nuclear Information System (INIS)

    Golman, K.; Holtz, E.; Almen, T.

    1987-01-01

    Contrast media are used in diagnostic radiology to enhance the X-ray attenuation between a body structure of interest and the surrounding tissue. A detail becomes perceptible on a roentgenogram only when its contrast exceeds a minimum value in relation to the background. Small areas of interest must have higher contrast than the background. The contrast effect depends on concentration of the contrast media with the body. A high contrast media concentration difference thus gives rise to more morphological details in the radiographs. Contrast media can be divided into negative contrast media such as air and gas which attenuate X-rays less than the body tissues, and positive contrast materials which attenuate X-rays more than the body tissues. The positive contrast media all contain either iodine (atomic number 53) or barium (atomic number 56) and can be divided into water-insoluble and water-soluble contrast media

  12. Comprehension of digital media

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Hwan

    2008-11-15

    This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

  13. Media:Time card stack

    NARCIS (Netherlands)

    Annemarie Wennekers; Jos de Haan; Frank Huysmans

    2016-01-01

    Original title: Media:Tijd in kaart The Dutch spend a daily average of 8 hours 33 minutes using media. Men and people aged over 50 spend most time using media, at an average of 9 hours per day. Older media users prefer traditional media and devices over new media and modern devices. Young and

  14. Understanding Social Media Logic

    Directory of Open Access Journals (Sweden)

    José van Dijck

    2013-08-01

    Full Text Available Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media logic—the norms, strategies, mechanisms, and economies—underpin­ning its dynamics. This logic will be considered in light of what has been identified as mass me­dia logic, which has helped spread the media's powerful discourse outside its institutional boundaries. Theorizing social media logic, we identify four grounding principles—programmabil­ity, popularity, connectivity, and datafication—and argue that these principles become increas­ingly entangled with mass media logic. The logic of social media, rooted in these grounding principles and strategies, is gradually invading all areas of public life. Besides print news and broadcasting, it also affects law and order, social activism, politics, and so forth. Therefore, its sustaining logic and widespread dissemination deserve to be scrutinized in detail in order to better understand its impact in various domains. Concentrating on the tactics and strategies at work in social media logic, we reassess the constellation of power relationships in which social practices unfold, raising questions such as: How does social media logic modify or enhance ex­isting mass media logic? And how is this new media logic exported beyond the boundaries of (social or mass media proper? The underlying principles, tactics, and strategies may be relat­ively simple to identify, but it is much harder to map the complex connections between plat­forms that distribute this logic: users that employ them, technologies that

  15. Hydro-Elastic Tailoring and Optimization of a Composite Marine Propeller

    DEFF Research Database (Denmark)

    Blasques, José Pedro Albergaria Amaral; Berggreen, Christian; Andersen, Poul

    2008-01-01

    direct search filter algorithm, is used together with DACE, a surface fitting algorithm, to determine the optimal laminate lay-up and blade pitch angle. The optimal configurations which reduce the fuel consumption for the combination of two load cases are found. The strength requirements......The following paper deals with the design and optimization of a flexible composite marine propeller. The blade shape is obtained from an existing high skew metal propeller. The aim is to tailor the laminate to control the elastic couplings and therefore the deformed shape of the blade...... are then analyzed using the Tsai-Wu failure criteria. The results show that it is possible to design a flexible composite marine propeller that will enable a reduction of the fuel consumption while withstanding the imposed loads....

  16. Experimental aeroacoustic study of a landing gear in the unsteady flow induced by a propeller

    Science.gov (United States)

    Chekiri, Rafik

    An aeroacoustic study of a two-strut, two-wheel, nacelle-mounted landing gear was conducted to investigate the effects of an upstream propeller on the radiated noise. The development of a 1:10.8 scale model based on a Bombardier Q400 aircraft, consisting of a propeller, motor, nacelle, and landing gear assembly is discussed. Comparisons are made between cases with and without an actuated upstream propeller. Far-field microphone measurements out of the airstream are presented to characterize the acoustic effects of each model component. The main strut and wheels of the model were equipped with surface-mounted microphones to measure unsteady pressures. It is shown that the noise signature of the landing gear cannot be observed over the tunnel background noise in the far-field. Unsteady surface pressures on the main strut show dominant peaks related to vortex shedding from the drag strut for both steady and unsteady upstream conditions.

  17. Propellant Mass Fraction Calculation Methodology for Launch Vehicles and Application to Ares Vehicles

    Science.gov (United States)

    Holt, James B.; Monk, Timothy S.

    2009-01-01

    Propellant Mass Fraction (pmf) calculation methods vary throughout the aerospace industry. While typically used as a means of comparison between candidate launch vehicle designs, the actual pmf calculation method varies slightly from one entity to another. It is the purpose of this paper to present various methods used to calculate the pmf of launch vehicles. This includes fundamental methods of pmf calculation that consider only the total propellant mass and the dry mass of the vehicle; more involved methods that consider the residuals, reserves and any other unusable propellant remaining in the vehicle; and calculations excluding large mass quantities such as the installed engine mass. Finally, a historical comparison is made between launch vehicles on the basis of the differing calculation methodologies, while the unique mission and design requirements of the Ares V Earth Departure Stage (EDS) are examined in terms of impact to pmf.

  18. Prediction and analysis of 3D hydrofoil and propeller under potential flow using panel method

    Directory of Open Access Journals (Sweden)

    Chen Chen-Wei

    2016-01-01

    Full Text Available Potential flow over an airfoil plays an important historical role in the theory of airfoil. The governing equation for potential flow is Laplace’s equation. One of Green’s identities can be used to write a solution to Laplace’s equation as a boundary integral. Using distributions of singularity solutions and determining their strength via the boundary conditions is the essence of panel method. This paper introduces a quick prediction method of three-dimensional hydrofoil and propeller performance based on panel method. The surface of hydrofoil and propeller is divided into numbers of quadrilateral panels. Combined sources with doublets singularities will be distributed on the corners of panels. Calculated blade pressure distributions of hydrofoil and propeller agree well with experimental data. Several sample calculations have been included using panel method.

  19. Ratchet composite thin film for low-temperature self-propelled Leidenfrost droplet.

    Science.gov (United States)

    Feng, Ruotao; Zhao, Wenjie; Wu, Xuedong; Xue, Qunji

    2012-02-01

    The droplet control, especially for the self-propelled Leidenfrost droplet, has attracted many researchers' attention in applied and fundamental fields. In this paper, the ratchet thin film was fabricated by magnetron sputtering and hybrid ion beams deposition. The micro- and nanoscale structure of the film was characterized by field emission scanning electron microscope. This study reports an interesting phenomenon that the self-propelled Leidenfrost water droplet was initiated at low temperature. The Leidenfrost point of droplets was controlled by the surface wettability and parameters of the asymmetric ratchet substrate. This novel self-propelled interfacial material and preparation technology can be expanded to the manufacture process and constructed a temperature-dependent tubule for microfluidic systems. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. A COMPUTATIONAL HYDRODYNAMIC ANALYSIS OF DUISBURG TEST CASE WITH FREE SURFACE AND PROPELLER

    Directory of Open Access Journals (Sweden)

    Omer Kemal Kinaci

    2016-01-01

    Full Text Available This paper discusses the effects of the free surface and the propeller on a benchmark Post-Panamax Ship, Duisburg Test Case (DTC. The experimental results are already available in the literature. The computational study carried out in this work is verified first with the experiments and then used to explain some of the physical aspects associated with viscous ship flows. There are two interesting outcomes of this work. The first one is, the existence of the propeller contributes to the pressure resistance of the ship by increasing the wave elevations along the hull and the fluid domain substantially. The second outcome is; by changing the pressure distribution along the hull and the propeller, the free surface increases the efficiency of the propulsion system. These specific outcomes are thoroughly discussed in the paper with CFD generated results and physical explanations.