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Sample records for composite marine propeller

  1. 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

    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. The develo...

  2. Hydro-elastic analysis and optimization of a composite marine propeller

    DEFF Research Database (Denmark)

    Blasques, José Pedro Albergaria Amaral; Berggreen, Christian; Andersen, Poul

    2010-01-01

    The present paper addresses the design and optimization of a flexible composite marine propeller. The aim is to tailor the laminate to control the deformed shape of the blade and consequently the developed thrust. The development of a hydro-elastic model is presented, and the laminate lay-up which...

  3. 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...... criteria and inviscid flow method, but a series of model test is costly and the other two methods have low accuracy. Nowadays, computational fluid dynamics by using a viscous flow solver is common for practical industrial applications in many disciplines. Cavitation models in viscous flow solvers have been...... hydrofoils and conventional/highly-skewed propellers are performed with one of three cavitation models proven in 2D analysis. 3D cases also show accuracy and robustness of numerical method in simulating steady and unsteady sheet cavitation on complicated geometries. Hydrodynamic characteristics of cavitation...

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

    DEFF Research Database (Denmark)

    Kappel, J.; Andersen, Poul

    2002-01-01

    The principle of non-planar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or "winglet" at the wingtip has been developed for aircraft, the application of the non-planar principle to marine propellers, dealt...... with in this paper, has led to the KAPPEL propeller with blades curved towards the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental and practical approach to develop and design marine propellers with non-planar lifting surfaces has resulted in propellers...

  5. Development of a Marine Propeller With Nonplanar Lifting Surfaces

    DEFF Research Database (Denmark)

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

    2005-01-01

    The principle of non-planar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or winglet at the wingtip has been developed for aircraft, the application of the nonplanar principle to marine propellers, dealt...... with in this paper, has led to the KAPPEL propeller with blades curved toward the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental, and practical approach to develop and design marine propellers with nonplanar lifting surfaces has resulted in propellers...

  6. 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

  7. Effect of Propellant Composition to the Temperature Sensitivity of Composite Propellant

    International Nuclear Information System (INIS)

    Aziz, Amir; Mamat, Rizalman; Amin, Makeen; Wan Ali, Wan Khairuddin

    2012-01-01

    The propellant composition is one of several parameter that influencing the temperature sensitivity of composite propellant. In this paper, experimental investigation of temperature sensitivity in burning rate of composite propellant was conducted. Four sets of different propellant compositions had been prepared with the combination of ammonium perchlorate (AP) as an oxidizer, aluminum (Al) as fuel and hydroxy-terminated polybutadiene (HTPB) as fuel and binder. For each mixture, HTPB binder was fixed at 15% and cured with isophorone diisocyanate (IPDI). By varying AP and Al, the effect of oxidizer- fuel mixture ratio (O/F) on the whole propellant can be determined. The propellant strands were manufactured using compression molded method and burnt in a strand burner using wire technique over a range of pressure from 1 atm to 31 atm. The results obtained shows that the temperature sensitivity, a, increases with increasing O/F. Propellant p80 which has O/F ratio of 80/20 gives the highest value of temperature sensitivity which is 1.687. The results shows that the propellant composition has significant effect on the temperature sensitivity of composite propellant

  8. Cavitation noise studies on marine propellers

    Science.gov (United States)

    Sharma, S. D.; Mani, K.; Arakeri, V. H.

    1990-04-01

    Experimental observations are described of cavitation inception and noise from five model propellers, three basic and two modified, tested in the open jet section of the Indian Institute of Science high-speed water tunnel facility. Extensive experiments on the three basic propellers of different design, which included visualization of cavitation and measurements of noise, showed that the dominant type of cavitation was in the form of tip vortex cavitation, accompanied by leading edge suction side sheet cavitation in its close vicinity, and the resultant noise depended on parameters such as the advance coefficient, the cavitation number, and the propeller geometry. Of these, advance coefficient was found to have the maximum influence not only on cavitation noise but also on the inception of cavitation. Noise levels and frequencies of spectra obtained from all the three basic propellers at conditions near inception and different advance coefficient values, when plotted in the normalized form as suggested by Blake, resulted in a universal spectrum which would be useful for predicting cavitation noise at prototype scales when a limited extent of cavitation is expected in the same form as observed on the present models. In an attempt to delay the onset of tip vortex cavitation, the blades of two of the three basic propellers were modified by drilling small holes in the tip and leading edge areas. Studies on the modified propellers showed that the effectiveness of the blade modification was apparently stronger at low advance coefficient values and depended on the blade sectional profile. Measurements of cavitation noise indicated that the modification also improved the acoustic performance of the propellers as it resulted in a complete attenuation of the low-frequency spectral peaks, which were prominent with the basic propellers. In addition to the above studies, which were conducted under uniform flow conditions, one of the basic propellers was tested in the simulated

  9. 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.

  10. Particle swarm optimization: an alternative in marine propeller optimization?

    Science.gov (United States)

    Vesting, F.; Bensow, R. E.

    2018-01-01

    This article deals with improving and evaluating the performance of two evolutionary algorithm approaches for automated engineering design optimization. Here a marine propeller design with constraints on cavitation nuisance is the intended application. For this purpose, the particle swarm optimization (PSO) algorithm is adapted for multi-objective optimization and constraint handling for use in propeller design. Three PSO algorithms are developed and tested for the optimization of four commercial propeller designs for different ship types. The results are evaluated by interrogating the generation medians and the Pareto front development. The same propellers are also optimized utilizing the well established NSGA-II genetic algorithm to provide benchmark results. The authors' PSO algorithms deliver comparable results to NSGA-II, but converge earlier and enhance the solution in terms of constraints violation.

  11. 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.

  12. Evaluation for probabilistic distributions of fatigue life of marine propeller materials by using a Monte Carlo simulation

    International Nuclear Information System (INIS)

    Yoon, Han Yong; Zhang, Jian Wei

    2008-01-01

    Engineering materials have been studied and developed remarkably for a long time. But, few reports about marine propeller materials are presented. Recently, some researchers have studied the material strength of marine propellers. However, studies on parametric sensitivity and probabilistic distribution of fatigue life of propeller materials have not been made yet. In this study, a method to predict the probabilistic distributions of fatigue life of propeller materials is presented, and the influence of several parameters on the life distribution is discussed

  13. 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.

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

    DEFF Research Database (Denmark)

    Shin, Keun Woo; Andersen, Poul

    2015-01-01

    investigated intensively by viscous flow solvers, although RANS CFD is prevalent in marine industry nowadays. In the current work, the cascade effect of a marine propeller is analyzed by CFD simulations on a threedimensional propeller model with varying the number of blades. The influence of trailing......-edge configurations on the cascade effect is also investigated by simulating CFD with varying trailingedge thickness and slope. The reason why the trailingedge is handled rather than other parts of bladegeometry is that it can be modified without altering overall blade thrust significantly, because the loading...

  15. 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...

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

    Science.gov (United States)

    Paik, Kwang-Jun; Park, Hyung-Gil; Seo, Jongsoo

    2013-12-01

    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.

  17. 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.

  18. Effect of gamma radiation on properties of a composite rocket propellant

    International Nuclear Information System (INIS)

    Dedgaonkar, V.G.; Pol, V.G.; Navle, P.B.; Ghorpade, V.G.; Wani, V.S.

    2000-01-01

    Gamma radiation was employed for modifying the properties of a composite rocket propellant prepared in a standard way. It was observed that when the same gamma dose was imparted to hydroxy terminated polybutadiene (HTPB) then converted into propellant, the enhancement in the properties was much larger than the irradiated propellant samples. (author)

  19. A critical pressure based panel method for prediction of unsteady loading of marine propellers under cavitation

    International Nuclear Information System (INIS)

    Liu, P.; Bose, N.; Colbourne, B.

    2002-01-01

    A simple numerical procedure is established and implemented into a time domain panel method to predict hydrodynamic performance of marine propellers with sheet cavitation. This paper describes the numerical formulations and procedures to construct this integration. Predicted hydrodynamic loads were compared with both a previous numerical model and experimental measurements for a propeller in steady flow. The current method gives a substantial improvement in thrust and torque coefficient prediction over a previous numerical method at low cavitation numbers of less than 2.0, where severe cavitation occurs. Predicted pressure coefficient distributions are also presented. (author)

  20. Observations of tip vortex cavitation inception from a model marine propeller

    Science.gov (United States)

    Lodha, R. K.; Arakeri, V. H.

    1984-01-01

    Cavitation inception characteristics of a model marine propeller having three blades, developed area ratio of 0.34 and at three different pitch to diameter ratios of 0.62, 0.83 and 1.0 are reported. The dominant type of cavitation observed at inception was the tip vortex type. The measured magnitude of inception index is found to agree well with a proposed correlation due to Strasberg. Performance calculations of the propeller based on combined vortex and blade element theory are also presented.

  1. Manganese oxalate nanorods as ballistic modifier for composite solid propellants

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Supriya [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India); Chawla, Mohit [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Siril, Prem Felix, E-mail: prem@iitmandi.ac.in [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Singh, Gurdip [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India)

    2014-12-10

    Highlights: • Manganese oxalate nanorods were prepared using mild thermal precipitation and aging. • The nanorods were found to be efficient ballistic modifier for solid propellants. • The nanorods sensitized the thermolysis of ammonium perchlorate. • Controlled thermal decomposition of nanorods yielded manganese oxide nanoparticles. • MnO nanoparticles formed insitu in the condensed phase enhance the burning rates. - Abstract: Rod-shaped nanostructures of manganese oxalate (MnC{sub 2}O{sub 4}) were synthesized via mild thermal precipitation and aging process. Chemical composition of the MnC{sub 2}O{sub 4} nanorods was confirmed using Fourier transform infra-red (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) and selected area electron diffraction (SAED) studies revealed the crystal structure. Field emission scanning electron microscopy (FE-SEM) imaging and high resolution transmission electron microscopy (HR-TEM) were employed to study the structural features of the nanorods. The MnC{sub 2}O{sub 4} nanorods were found to be efficient ballistic modifier for the burning rate enhancement of composite solid propellants (CSPs). Thermal analysis using TGA-DSC showed that MnC{sub 2}O{sub 4} nanorods sensitized the thermal decomposition of ammonium perchlorate (AP) and the CSPs. Controlled thermal decomposition of the MnC{sub 2}O{sub 4} nanorods resulted in the formation of managanese oxide nanoparticles with mesoporosity. A plausible mechanism for the burning rate enhancement using MnC{sub 2}O{sub 4} nanorods was proposed.

  2. Thermal Decomposition Behaviors and Burning Characteristics of AN/Nitramine-Based Composite Propellant

    Science.gov (United States)

    Naya, Tomoki; Kohga, Makoto

    2015-04-01

    Ammonium nitrate (AN) has attracted much attention due to its clean burning nature as an oxidizer. However, an AN-based composite propellant has the disadvantages of low burning rate and poor ignitability. In this study, we added nitramine of cyclotrimethylene trinitramine (RDX) or cyclotetramethylene tetranitramine (HMX) as a high-energy material to AN propellants to overcome these disadvantages. The thermal decomposition and burning rate characteristics of the prepared propellants were examined as the ratio of AN and nitramine was varied. In the thermal decomposition process, AN/RDX propellants showed unique mass loss peaks in the lower temperature range that were not observed for AN or RDX propellants alone. AN and RDX decomposed continuously as an almost single oxidizer in the AN/RDX propellant. In contrast, AN/HMX propellants exhibited thermal decomposition characteristics similar to those of AN and HMX, which decomposed almost separately in the thermal decomposition of the AN/HMX propellant. The ignitability was improved and the burning rate increased by the addition of nitramine for both AN/RDX and AN/HMX propellants. The increased burning rates of AN/RDX propellants were greater than those of AN/HMX. The difference in the thermal decomposition and burning characteristics was caused by the interaction between AN and RDX.

  3. 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

  4. High-Fidelity Microstructural Characterization and Performance Modeling of Aluminized Composite Propellant

    International Nuclear Information System (INIS)

    Kosiba, Graham D.; Wixom, Ryan R.; Oehlschlaeger, Matthew A.

    2017-01-01

    Image processing and stereological techniques were used to characterize the heterogeneity of composite propellant and inform a predictive burn rate model. Composite propellant samples made up of ammonium perchlorate (AP), hydroxyl-terminated polybutadiene (HTPB), and aluminum (Al) were faced with an ion mill and imaged with a scanning electron microscope (SEM) and x-ray tomography (micro-CT). Properties of both the bulk and individual components of the composite propellant were determined from a variety of image processing tools. An algebraic model, based on the improved Beckstead-Derr-Price model developed by Cohen and Strand, was used to predict the steady-state burning of the aluminized composite propellant. In the presented model the presence of aluminum particles within the propellant was introduced. The thermal effects of aluminum particles are accounted for at the solid-gas propellant surface interface and aluminum combustion is considered in the gas phase using a single global reaction. In conclusion, properties derived from image processing were used directly as model inputs, leading to a sample-specific predictive combustion model.

  5. The use of image analysis for the study of interfacial bonding in solid composite propellant

    Directory of Open Access Journals (Sweden)

    JASMINA DOSTANIC

    2007-10-01

    Full Text Available In the framework of this research, the program Image Pro Plus was applied for determining the polymer–oxidizer interactions in HTPB-based composite propellants. In order to improve the interactions, different bonding agents were used, and their efficiency was analyzed. The determination of the quantity, area and radius of non-bonded oxidizer crystals is presented. The position of formed cracks in the specimen and their area has a great influence on the mechanical properties of composite propellant. The preparation of the composite propellant in order to enable the photographing of their structure by means of stereoscopic and metallographic microscopes with the digital camera is also described as well.

  6. Studies on composite solid propellant with tri-modal ammonium perchlorate containing an ultrafine fraction

    Directory of Open Access Journals (Sweden)

    K.V. Suresh Babu

    2017-08-01

    Full Text Available Composite solid propellant is prepared using tri-modal Ammonium perchlorate (AP containing coarse, fine and ultrafine fractions of AP with average particle size (APS 340, 40 and 5 μm respectively, in various compositions and their rheological, mechanical and burn rate characteristics are evaluated. The optimum combination of AP coarse to fine to ultrafine weight fraction was obtained by testing of series of propellant samples by varying the AP fractions at fixed solid loading. The concentration of aluminium was maintained constant throughout the experiments for ballistics requirement. The propellant formulation prepared using AP with coarse to fine to ultrafine ratio of 67:24:9 has lowest viscosity for the propellant paste and highest tensile strength due to dense packing as supported by the literature. A minimum modulus value was also observed at 9 wt. % of ultrafine AP concentration indicates the maximum solids packing density at this ratio of AP fractions. The burn rate is evaluated at different pressures to obtain pressure exponent. Incorporation of ultrafine fraction of AP in propellant increased burn rate without adversely affecting the pressure exponent. Higher solid loading propellants are prepared by increased AP concentration from 67 to 71 wt. % using AP with coarse to fine to ultrafine ratio of 67:24:9. Higher solid content up to 89 wt. % was achieved and hence increased solid motor performance. The unloading viscosity showed a trend with increased AP content and the propellant couldn't able to cast beyond 71 wt. % of AP. Mechanical properties were also studied and from the experiments noticed that % elongation decreased with increased AP content from 67 to 71 wt.%, whereas tensile strength and modulus increased. Burn rate increased with increased AP content and observed that pressure exponent also increased and it is high for the propellant containing with 71 wt.% of AP due to increased oxidiser to fuel ratio. Catalysed

  7. Cu–Co–O nano-catalysts as a burn rate modifier for composite solid propellants

    Directory of Open Access Journals (Sweden)

    D. Chaitanya Kumar Rao

    2016-08-01

    Full Text Available Nano-catalysts containing copper–cobalt oxides (Cu–Co–O have been synthesized by the citric acid (CA complexing method. Copper (II nitrate and Cobalt (II nitrate were employed in different molar ratios as the starting reactants to prepare three types of nano-catalysts. Well crystalline nano-catalysts were produced after a period of 3 hours by the calcination of CA–Cu–Co–O precursors at 550 °C. The phase morphologies and crystal composition of synthesized nano-catalysts were examined using Scanning Electron Microscope (SEM, Energy Dispersive Spectroscopy (EDS and Fourier Transform Infrared Spectroscopy (FTIR methods. The particle size of nano-catalysts was observed in the range of 90 nm–200 nm. The prepared nano-catalysts were used to formulate propellant samples of various compositions which showed high reactivity toward the combustion of HTPB/AP-based composite solid propellants. The catalytic effects on the decomposition of propellant samples were found to be significant at higher temperatures. The combustion characteristics of composite solid propellants were significantly improved by the incorporation of nano-catalysts. Out of the three catalysts studied in the present work, CuCo-I was found to be the better catalyst in regard to thermal decomposition and burning nature of composite solid propellants. The improved performance of composite solid propellant can be attributed to the high crystallinity, low agglomeration and lowering the decomposition temperature of oxidizer by the addition of CuCo-I nano-catalyst.

  8. Friction-stir processing of a high-damping Mn-Cu alloy used for marine propellers

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, S.P.; Edwards, D.P.; Majumdar, A. [Defence Science and Technology Organisation, Melbourne (Australia); Moutsos, S. [Centre for Advanced Materials Technology, Monash Univ. (Australia); Mahoney, M.W. [Rockwell Scientific, Thousand Oaks (United States)

    2003-07-01

    Mn-Cu alloys are used for specialised applications, such as marine propellers, where high noise-damping characteristics are required. These alloys tend to have more severe shrinkage porosity than conventional propeller alloys, and the corrosion resistance (including stress-corrosion and corrosion-fatigue resistance) of the alloys is not as high as desirable. Friction-stir processing (FSP) trials on one such alloy (tradename Sonoston) have shown that near-surface porosity can be eliminated and that the coarse, as-cast microstructure can be significantly refined. The corrosion resistance of processed material is substantially improved provided a heat treatment to relieve residual stress is carried out after FSP. (orig.)

  9. 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.

  10. Numerical investigation of the flow in axial water turbines and marine propellers with scale-resolving simulations

    Science.gov (United States)

    Morgut, Mitja; Jošt, Dragica; Nobile, Enrico; Škerlavaj, Aljaž

    2015-11-01

    The accurate prediction of the performances of axial water turbines and naval propellers is a challenging task, of great practical relevance. In this paper a numerical prediction strategy, based on the combination of a trusted CFD solver and a calibrated mass transfer model, is applied to the turbulent flow in axial turbines and around a model scale naval propeller, under non-cavitating and cavitating conditions. Some selected results for axial water turbines and a marine propeller, and in particular the advantages, in terms of accuracy and fidelity, of ScaleResolving Simulations (SRS), like SAS (Scale Adaptive Simulation) and Zonal-LES (ZLES) compared to standard RANS approaches, are presented. Efficiency prediction for a Kaplan and a bulb turbine was significantly improved by use of the SAS SST model in combination with the ZLES in the draft tube. Size of cavitation cavity and sigma break curve for Kaplan turbine were successfully predicted with SAS model in combination with robust high resolution scheme, while for mass transfer the Zwart model with calibrated constants were used. The results obtained for a marine propeller in non-uniform inflow, under cavitating conditions, compare well with available experimental measurements, and proved that a mass transfer model, previously calibrated for RANS (Reynolds Averaged Navier Stokes), can be successfully applied also within the SRS approaches.

  11. Radiative Ignition of fine-ammonium perchlorate composite propellants

    Energy Technology Data Exchange (ETDEWEB)

    Cain, Jeremy; Brewster, M. Quinn [Department of Mechanical Science and Industrial Engineering, University of Illinois, Urbana, IL 61801 (United States)

    2006-08-15

    Radiative ignition of quasi-homogeneous mixtures of ammonium perchlorate (AP) and hydroxyterminated polybutadiene (HTPB) binder has been investigated experimentally. Solid propellants consisting of fine AP (2 {mu}m) and HTPB binder ({proportional_to}76/24% by mass) were ignited by CO{sub 2} laser radiation. The lower boundary of a go/no-go ignition map (minimum ignition time vs. heat flux) was obtained. Opacity was varied by adding carbon black up to 1% by mass. Ignition times ranged from 0.78 s to 0.076 s for incident fluxes ranging from 60 W/cm{sup 2} to 400 W/cm{sup 2}. It was found that AP and HTPB are sufficiently strongly absorbing of 10.6 {mu}m CO{sub 2} laser radiation (absorption coefficient {approx}250 cm{sup -1}) so that the addition of carbon black in amounts typical of catalysts or opacitymodifying agents (up to 1%) would have only a small influence on radiative ignition times at 10.6 {mu}m. A simple theoretical analysis indicated that the ignition time-flux data are consistent with in-depth absorption effects. Furthermore, this analysis showed that the assumption of surface absorption is not appropriate, even for this relatively opaque system. For broadband visible/near-infrared radiation, such as from burning metal/oxide particle systems, the effects of in-depth absorption would probably be even stronger. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  12. Burning characteristics of ammonium nitrate-based composite propellants supplemented with ammonium dichromate

    Energy Technology Data Exchange (ETDEWEB)

    Kohga, Makoto; Nishino, Saeko [Department of Applied Chemistry, National Defense Academy, Yokosuka, Kanagawa 239-8686 (Japan)

    2009-08-15

    Ammonium nitrate (AN)-based composite propellants have attracted much attention, primarily because of the clean burning nature of AN as an oxidizer. However, such propellants have some disadvantages such as poor ignition and low burning rate. Ammonium dichromate (ADC) is used as a burning catalyst for AN-based propellants; however, the effect of ADC on the burning characteristics has yet to be sufficiently delineated. The burning characteristics of AN/ADC propellants prepared with various contents of AN and ADC have been investigated in this study. The theoretical performance of an AN-based propellant is improved by the addition of ADC. The increase in the burning rate is enhanced and the pressure deflagration limit (PDL) becomes lower with increasing amount of ADC added. The increasing ratio of the burning rate with respect to the amount of ADC is independent of the AN content and the combustion pressure. The optimal amount of ADC for improving the burning characteristics has been determined. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  13. Experimental study on composite solid propellant material burning rate using algorithm MATLAB

    Directory of Open Access Journals (Sweden)

    Thunaipragasam Selvakumaran

    2016-01-01

    Full Text Available In rocketry application, now-a-days instead of monopropellants slowly composite propellants are introduced. Burning rate of a solid state composite propellant depends on many factors like oxidizer-binder ratio, oxidizer particle size and distribution, particle size and its distribution, pressure, temperature, etc. Several researchers had taken the mass varied composite propellant. In that, the ammonium perchlorate mainly varied from 85 to 90%. This paper deals with the oxidizer rich propellant by allowing small variation of fuel cum binder ranging from 2%, 4%, 6%, and 8% by mass. Since the percent of the binder is very less compared to the oxidizer, the mixture remains in a powder form. The powder samples are used to make a pressed pellet. Experiments were conducted in closed window bomb set-up at pressures of 2, 3.5, and 7 MN/m2. The burning rates are calculated from the combustion photography (images taken by a high-speed camera. These images were processed frame by frame in MATLAB, detecting the edges in the images of the frames. The burning rate is obtained as the slope of the linear fit from MATLAB and observed that the burn rate increases with the mass variation of constituents present in solid state composite propellant. The result indicates a remarkable increase in burn rate of 26.66%, 20%, 16.66%, and 3.33% for Mix 1, 2, 3, 4 compared with Mix 5 at 7 MN/m2. The percentage variations in burn rate between Mix 1 and Mix 5 at 2, 3.5, and 7 MN/m2 are 25.833%, 32.322%, and 26.185%, respectively.

  14. Durability of composites in a marine environment

    CERN Document Server

    Rajapakse, Yapa

    2014-01-01

    Composites are widely used in marine applications. There is considerable experience of glass reinforced resins in boats and ships but these are usually not highly loaded. However, for new areas such as offshore and ocean energy there is a need for highly loaded structures to survive harsh conditions for 20 years or more. High performance composites are therefore being proposed. This book provides an overview of the state of the art in predicting the long term durability of composite marine structures. The following points are covered: •       Modelling water diffusion •       Damage induced by water •       Accelerated testing •       Including durability in design •       In-service experience. This is essential reading for all those involved with composites in the marine industry, from initial design and calculation through to manufacture and service exploitation. It also provides information unavailable elsewhere on the mechanisms involved in degradation and how to t...

  15. 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.

  16. 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

  17. The thermal decomposition behavior of ammonium perchlorate and of an ammonium-perchlorate-based composite propellant

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, R.; Minier, L.

    1998-03-24

    The thermal decomposition of ammonium perchlorate (AP) and ammonium-perchlorate-based composite propellants is studied using the simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) technique. The main objective of the present work is to evaluate whether the STMBMS can provide new data on these materials that will have sufficient detail on the reaction mechanisms and associated reaction kinetics to permit creation of a detailed model of the thermal decomposition process. Such a model is a necessary ingredient to engineering models of ignition and slow-cookoff for these AP-based composite propellants. Results show that the decomposition of pure AP is controlled by two processes. One occurs at lower temperatures (240 to 270 C), produces mainly H{sub 2}O, O{sub 2}, Cl{sub 2}, N{sub 2}O and HCl, and is shown to occur in the solid phase within the AP particles. 200{micro} diameter AP particles undergo 25% decomposition in the solid phase, whereas 20{micro} diameter AP particles undergo only 13% decomposition. The second process is dissociative sublimation of AP to NH{sub 3} + HClO{sub 4} followed by the decomposition of, and reaction between, these two products in the gas phase. The dissociative sublimation process occurs over the entire temperature range of AP decomposition, but only becomes dominant at temperatures above those for the solid-phase decomposition. AP-based composite propellants are used extensively in both small tactical rocket motors and large strategic rocket systems.

  18. Differential scanning calorimetric study of HTPB based composite propellants in presence of nano ferric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Prajakta R.; Krishnamurthy, V.N.; Joshi, Satyawati S. [Department of Chemistry, University of Pune, Pune 411007 (India)

    2006-12-15

    A comparative study of the thermal decomposition of ammonium perchlorate (AP)/hydroxy terminated polybutadiene (HTPB) based composite propellants has been carried out in presence and absence of nano iron oxide at different heating rates in a dynamic nitrogen atmosphere using differential scanning calorimetry. The pronounced effect was a lowering of the high temperature decomposition by 49 C. A higher heat release up to 40% was observed in presence of nano ferric oxide (3.5 nm). The kinetic parameters were evaluated using the Kissinger method. The increase of the rate constant in the catalyzed propellant confirmed the enhancement of the catalytic activity of ammonium perchlorate. The scanning electron micrographs of nano Fe{sub 2}O{sub 3} incorporated in HTPB revealed a well-separated characteristic necklace-like structure of {alpha}-Fe{sub 2}O{sub 3} particles at high magnification. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  19. Modeling of robotic fish propelled by an ionic polymer-metal composite caudal fin

    Science.gov (United States)

    Chen, Zheng; Shatara, Stephan; Tan, Xiaobo

    2009-03-01

    In this paper, a model is proposed for a biomimetic robotic fish propelled by an ionic polymer metal composite (IPMC) actuator with a rigid passive fin at the end. The model incorporates both IPMC actuation dynamics and the hydrodynamics, and predicts the steady-state speed of the robot under a periodic actuation voltage. Experimental results have shown that the proposed model can predict the fish motion for different tail dimensions. Since its parameters are expressed in terms of physical properties and geometric dimensions, the model is expected to be instrumental in optimal design of the robotic fish.

  20. Effective Mechanical Property Estimation of Composite Solid Propellants Based on VCFEM

    Directory of Open Access Journals (Sweden)

    Liu-Lei Shen

    2018-01-01

    Full Text Available A solid rocket motor is one of the critical components of solid missiles, and its life and reliability mostly depend on the mechanical behavior of a composite solid propellant (CSP. Effective mechanical properties are critical material constants to analyze the structural integrity of propellant grain. They are estimated by a numerical method that combines the Voronoi cell finite element method (VCFEM and the homogenization method in the present paper. The correctness of this combined method has been validated by comparing with a standard finite element method and conventional theoretical models. The effective modulus and the effective Poisson’s ratio of a CSP varying with volume fraction and component material properties are estimated. The result indicates that the variations of the volume fraction of inclusions and the properties of the matrix have obvious influences on the effective mechanical properties of a CSP. The microscopic numerical analysis method proposed in this paper can also be used to provide references for the design and the analysis of other large volume fraction composite materials.

  1. Development of an Analysis and Design Optimization Framework for Marine Propellers

    Science.gov (United States)

    Tamhane, Ashish C.

    In this thesis, a framework for the analysis and design optimization of ship propellers is developed. This framework can be utilized as an efficient synthesis tool in order to determine the main geometric characteristics of the propeller but also to provide the designer with the capability to optimize the shape of the blade sections based on their specific criteria. A hybrid lifting-line method with lifting-surface corrections to account for the three-dimensional flow effects has been developed. The prediction of the correction factors is achieved using Artificial Neural Networks and Support Vector Regression. This approach results in increased approximation accuracy compared to existing methods and allows for extrapolation of the correction factor values. The effect of viscosity is implemented in the framework via the coupling of the lifting line method with the open-source RANSE solver OpenFOAM for the calculation of lift, drag and pressure distribution on the blade sections using a transition kappa-o SST turbulence model. Case studies of benchmark high-speed propulsors are utilized in order to validate the proposed framework for propeller operation in open-water conditions but also in a ship's wake.

  2. Modeling and simulation of the debonding process of composite solid propellants

    Science.gov (United States)

    Feng, Tao; Xu, Jin-sheng; Han, Long; Chen, Xiong

    2017-07-01

    In order to study the damage evolution law of composite solid propellants, the molecular dynamics particle filled algorithm was used to establish the mesoscopic structure model of HTPB(Hydroxyl-terminated polybutadiene) propellants. The cohesive element method was employed for the adhesion interface between AP(Ammonium perchlorate) particle and HTPB matrix and the bilinear cohesive zone model was used to describe the mechanical response of the interface elements. The inversion analysis method based on Hooke-Jeeves optimization algorithm was employed to identify the parameters of cohesive zone model(CZM) of the particle/binder interface. Then, the optimized parameters were applied to the commercial finite element software ABAQUS to simulate the damage evolution process for AP particle and HTPB matrix, including the initiation, development, gathering and macroscopic crack. Finally, the stress-strain simulation curve was compared with the experiment curves. The result shows that the bilinear cohesive zone model can accurately describe the debonding and fracture process between the AP particles and HTPB matrix under the uniaxial tension loading.

  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. On-Demand Spare Parts for the Marine Industry with Directed Energy Deposition : Propeller Use Case

    NARCIS (Netherlands)

    Ya, Wei; Hamilton, Kelvin; Meboldt, Mirko; Klahn, Christoph

    2017-01-01

    As additive manufacturing (AM) gains greater industrial exposure, there is a drive towards defining practical, high-value processes and products. Defining viable business cases is critical to ensure successful technology adoption. Given the marine industry’s slow uptake of AM, the potential of Wire

  5. Factors controlling the compositional variations among the marine and non-marine black shales from Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Baioumy, Hassan M. [Central Metallurgical R and D Institute, PO Box 87 Helwan, Cairo (Egypt); Ismael, Ismael S. [Faculty of Science, Suez Canal University, Suez (Egypt)

    2010-07-01

    Non-marine (Jurassic) and marine (Cretaceous) black shales from Egypt were subjected to mineralogical and geochemical analyses to examine the controlling factors of their compositional variations. Non-marine black shales are composed of kaolinite and quartz with traces of gypsum, illite, calcite, feldspars, and dolomite, while marine black shales from the Red Sea area are composed of smectite, kaolinite, quartz, calcite, and dolomite with traces of feldspars. Abu Tartur marine black shales are composed of smectite and quartz with traces of feldspars and gypsum. Non-marine black shales show considerably higher Nb, Ta, Hf, and Zr contents and Th/Yb ratios compared to the marine black shales. On the other hand, marine black shales show considerably higher Cr, V, and Zn contents with positive correlations between these elements and organic carbon (C{sub org.}){sub .} Red Sea black shales have higher Ni/Co, V/Cr, and U/Al ratios. Chondrite normalized values of the medium and heavy rare earth elements (MREEs and HREEs, respectively) are higher in the non-marine black shales compared to the marine black shales. Pyrite from non-marine black shales is characterized by high positive {delta}{sup 34}S isotope values (average of + 9.3 permille). Pyrite from Red Sea black shales has low negative {delta}{sup 34}S values (average of -16.7 permille), pyrite from black shales of the lower member of the Duwi Formation has positive {delta}{sup 34}S values (average of 5.8 permille), while pyrite from marine black shales of the middle member has negative {delta}{sup 34}S values (average of -0.83 permille). Source area composition, weathering conditions, depositional environments, and type of organic matter are considered to be the probable controlling factors of these variations. The more felsic constituents in the source area of non-marine black shales is responsible for the relatively high Nb, Ta, Hf, and Zr contents and Th/Yb ratio. Relatively high kaolinite contents and Chemical

  6. Thermal Decomposition Behaviors and Burning Characteristics of AN/RDX-Based Composite Propellants Supplemented with MnO2 and Fe2O3

    Science.gov (United States)

    Kohga, Makoto; Naya, Tomoki

    2015-10-01

    Ammonium nitrate (AN)-based composite propellants have gained popularity because of the clean burning nature of AN as an oxidizer. However, such propellants have several disadvantages such as poor ignition and low burning rate. The burning characteristics of the AN propellant were improved when a portion of this propellant was replaced by an energetic material and the addition of a catalyst. In this study, RDX (1,3,5-trinitroperhydro-1,3,5-triazine) was used as the energetic material, and Fe2O3 and MnO2 were used as catalysts. The burning characteristics of the AN/RDX propellants supplemented with catalysts were investigated, and the effects of the replacement of AN by RDX and the catalyst addition were evaluated.

  7. Nature and composition of interbedded marine basaltic pumice in the

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 126; Issue 2. Nature and composition of interbedded marine basaltic pumice in the ~52–50 Ma Vastan lignite sequence, western India: Implication for Early Eocene MORB volcanism offshore Arabian Sea. Sarajit Sensarma Hukam Singh R S Rana Debajyoti Paul ...

  8. Production defects in marine composite structures

    DEFF Research Database (Denmark)

    Hayman, Brian; Berggreen, Christian; Tsouvalis, Nicholas G.

    2007-01-01

    Composite structures are often used when there is a requirement for low weight. Then a key aspect is to be able to take full advantage of the material and utilise it to its limits. To do this it is important to achieve as low a variability as possible in the manufacture of such structures...

  9. Finite element implementation of a thermo-damage-viscoelastic constitutive model for hydroxyl-terminated polybutadiene composite propellant

    Science.gov (United States)

    Xu, Jinsheng; Han, Long; Zheng, Jian; Chen, Xiong; Zhou, Changsheng

    2017-11-01

    A thermo-damage-viscoelastic model for hydroxyl-terminated polybutadiene (HTPB) composite propellant with consideration for the effect of temperature was implemented in ABAQUS. The damage evolution law of the model has the same form as the crack growth equation for viscoelastic materials, and only a single damage variable S is considered. The HTPB propellant was considered as an isotropic material, and the deviatoric and volumetric strain-stress relations are decoupled and described by the bulk and shear relaxation moduli, respectively. The stress update equations were expressed by the principal stresses σ_{ii}R and the rotation tensor M, the Jacobian matrix in the global coordinate system J_{ijkl} was obtained according to the fourth-order tensor transformation rules. Two models having complex stress states were used to verify the accuracy of the constitutive model. The test results showed good agreement with the strain responses of characteristic points measured by a contactless optical deformation test system, which illustrates that the thermo-damage-viscoelastic model perform well at describing the mechanical properties of an HTPB propellant.

  10. Study on Design of High Efficiency and Light Weight Composite Propeller Blade for a Regional Turboprop Aircraft

    Science.gov (United States)

    Kong, Changduk; Lee, Kyungsun

    2013-03-01

    In this study, aerodynamic and structural design of the composite propeller blade for a regional turboprop aircraft is performed. The thin and wide chord propeller blade of high speed turboprop aircraft should have proper strength and stiffness to carry various kinds of loads such as high aerodynamic bending and twisting moments and centrifugal forces. Therefore the skin-spar-foam sandwich structure using high strength and stiffness carbon/epoxy composite materials is used to improve the lightness. A specific design procedure is proposed in this work as follows; firstly the aerodynamic configuration design, which is acceptable for the design requirements, is carried out using the in-house code developed by authors, secondly the structure design loads are determined through the aerodynamic load case analysis, thirdly the spar flange and the skin are preliminarily sized by consideration of major bending moments and shear forces using both the netting rule and the rule of mixture, and finally, the stress analysis is performed to confirm the structural safety and stability using finite element analysis commercial code, MSC. NASTRAN/PATRAN. Furthermore the additional analysis is performed to confirm the structural safety due to bird strike impact on the blade during flight operation using a commercial code, ANSYS. To realize the proposed propeller design, the prototype blades are manufactured by the following procedure; the carbon/epoxy composite fabric prepregs are laid up for skin and spar on a mold using the hand lay-up method and consolidated with a proper temperature and vacuum in the oven. To finalize the structural design, the full-scale static structural test is performed under the simulated aerodynamic loads using 3 point loading method. From the experimental results, it is found that the designed blade has a good structural integrity, and the measured results agree well with the analytical results as well.

  11. Marine sources influence fog bioaerosol composition in Namibia and Maine

    Science.gov (United States)

    Evans, S. E.; Dueker, E.; Logan, J. R. V.; Weathers, K. C.

    2017-12-01

    Organic aerosol particles act as condensation nuclei for fogs and clouds (CCN) and are main determinants of fog evolution, chemical processing, and overall aerosol-fog-cloud interactions. Recent work has confirmed the presence of marine bioaerosols, but little is known about their sources, transport, taxonomic diversity or viability. The few studies that have characterized bioaerosols in fog have been limited to culture-based approaches that capture only a fraction of microbial diversity. We characterized fungal and bacterial communities in the fog in two iconic fog systems, the Coast of Maine (USA) and the Namib Desert (Namibia). The biology of fog in both systems was diverse and distinct, by geography, from dry aerosols, and from local sources. The local environment had a dominant influence on fog in both the Namib and Maine; in particular, the biology of fog in Maine, which was collected near the coast, was more similar to microbial communities from the ocean surface. In both systems, differences between pre- and post-fog aerosol communities suggest that fog events can significantly alter microbial aerosol diversity and composition. This insight into the microbial composition of fog indicates that its origin and frequency has the potential to influence the number and diversity of microorganisms that settle in a given environment, and the composition of microbial aerosol communities in ambient or clear conditions. Here we suggest that fog microbes can possess specific traits that enhance nucleation, altering the transport and deposition of marine- and soil-derived organic matter in terrestrial systems.

  12. Investigation of the interfacial bonding in composite propellants. 1,3,5-Trisubstituted isocyanurates as universal bonding agents

    Directory of Open Access Journals (Sweden)

    GORDANA S. USCUMLIC

    2006-05-01

    Full Text Available A series of 1,3,5-trisubstituted isocyanurates (substituents: CH2CH2OH, CH2CH=CH2 and CH2CH2COOH was synthesized according to a modified literature procedure. Experimental investigations included modification of the synthetic procedure in terms of the starting materials, solvents, temperature, isolation techniques, as well as purification and identification of the products. All the synthesized isocyanurates were identified by their melting point and FTIR, 1H NMR and UV spectroscopic data. Fourier transform infrared spectrophotometry was also used to study the interaction between ammonium perchlorate, hydroxyl terminated poly(butadiene, carboxyl terminated poly(butadiene, poly(butadiene-co-acrylonitrile, poly(propylene ether, cyclotrimethylenetrinitramine and the compounds synthesized in this work, which can serve as bonding agents. The results show that tris(2-hydroxyethylisocyanurate is a universal bonding agent for the ammonium perchlorate/carboxyl terminated poly(butadiene/cyclotrimethylenetrinitramine composite propellant system.

  13. A glimpse into the future composition of marine phytoplankton communities

    Directory of Open Access Journals (Sweden)

    Esteban eAcevedo-Trejos

    2014-07-01

    Full Text Available It is expected that climate change will have significant impacts on ecosystems. Most model projections agree that the ocean will experience stronger stratification and less nutrient supply from deep waters. These changes will likely affect marine phytoplankton communities and will thus impact on the higher trophic levels of the oceanic food web. The potential consequences of future climate change on marine microbial communities can be investigated and predicted only with the help of mathematical models. Here we present the application of a model that describes aggregate properties of marine phytoplankton communities and captures the effects of a changing environment on their composition and adaptive capacity. Specifically, the model describes the phytoplankton community in terms of total biomass, mean cell size, and functional diversity. The model is applied to two contrasting regions of the Atlantic Ocean (tropical and temperate and is tested under two emission scenarios: SRES A2 or ``business as usual'' and SRES B1 or ``local utopia''. We find that all three macroecological properties will decline during the next century in both regions, although this effect will be more pronounced in the temperate region. Being consistent with previous model predictions, our results show that a simple trait-based modelling framework represents a valuable tool for investigating how phytoplankton communities may reorganize under a changing climate.

  14. Development of an injectable chitosan/marine collagen composite gel

    International Nuclear Information System (INIS)

    Wang Wei; Itoh, Soichiro; Aizawa, Tomoyasu; Demura, Makoto; Okawa, Atsushi; Sakai, Katsuyoshi; Ohkuma, Tsuneo

    2010-01-01

    A chitosan/marine-originated collagen composite has been developed. This composite gel was characterized and its biocompatibility, as well as an inflammatory reaction, was observed. The chitosan gel including N-3-carboxypropanoil-6-O-(carboxymethyl) chitosan of 3 mol%, 6-O-(carboxymethyl) chitosan of 62 mol% and 6-O-(carboxymethyl) chitin of 35 mol% was prepared and compounded with the salmon atelocollagen (SA) gel at different mixture ratios. The composite gels were injected subcutaneously in to the back of rats. The specimens were harvested for a histological survey as well as a tumor necrosis factor-alpha (TNF-α) assay by ELISA. The inflammatory cell infiltration and release of TNF-α were successively controlled low with the ratio of SA to chitosan at 10:90 or 20:80. The SA gel first, within 2 weeks, and then chitosan in the composite gel were slowly absorbed after implantation, followed by soft tissue formation. It is expected that this composite gel will be available as a carrier for tissue filler and drug delivery systems.

  15. Effects of magnesium-based hydrogen storage materials on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant.

    Science.gov (United States)

    Liu, Leili; Li, Jie; Zhang, Lingyao; Tian, Siyu

    2018-01-15

    MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 were prepared, and their structure and hydrogen storage properties were determined through X-ray photoelectron spectroscopy and thermal analyzer. The effects of MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant were subsequently studied. Results indicated that MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 can decrease the thermal decomposition peak temperature and increase the total released heat of decomposition. These compounds can improve the effect of thermal decomposition of the propellant. The burning rates of the propellant increased using Mg-based hydrogen storage materials as promoter. The burning rates of the propellant also increased using MgH 2 instead of Al in the propellant, but its explosive heat was not enlarged. Nonetheless, the combustion heat of MgH 2 was higher than that of Al. A possible mechanism was thus proposed. Copyright © 2017. Published by Elsevier B.V.

  16. Marine litter in the Nordic Seas: Distribution composition and abundance.

    Science.gov (United States)

    Buhl-Mortensen, Lene; Buhl-Mortensen, Pål

    2017-12-15

    Litter has been found in all marine environments and is accumulating in seabirds and mammals in the Nordic Seas. These ecosystems are under pressure from climatic change and fisheries while the human population is small. The marine landscapes in the area range from shallow fishing banks to deep-sea canyons. We present density, distribution and composition of litter from the first large-scale mapping of sea bed litter in arctic and subarctic waters. Litter was registered from 1778 video transects, of which 27% contained litter. The background density of litter in the Barents Sea and Norwegian Sea is 202 and 279 items/km 2 respectively, and highest densities were found close to coast and in canyons. Most of the litter originated from the fishing industry and plastic was the second most common litter. Background levels were comparable to European records and areas with most littering had higher densities than in Europe. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Paleolatitudinal Gradients in Marine Phytoplankton Composition and Cell Size

    Science.gov (United States)

    Henderiks, J.; Bordiga, M.; Bartol, M.; Šupraha, L.

    2014-12-01

    Coccolithophores, a prominent group of marine calcifying unicellular algae, are widely studied in context of current and past climate change. We know that marine phytoplankton are sensitive to climatic changes, but the complex interplay of several processes such as warming, changes in nutrient content, and ocean acidification, makes future scenarios difficult to predict. Some taxa may be more susceptible to environmental perturbations than others, as evidenced by significantly different species-specific sensitivities observed in laboratory experiments. However, short-term plastic responses may not translate into longer-term climatic adaptation, nor should we readily extrapolate the behavior of single strains in the laboratory to natural, multi-species assemblages and their interactions in the ocean. The extensive fossil record of coccolithophores (in the form of coccoliths) reveals high morphological and taxonomic diversity and allows reconstructing the cell size of individual taxonomic groups. In a suite of deep-sea drilling sites from the Atlantic Ocean, we document distinct latitudinal gradients in phytoplankton composition and cell size across major climate transitions of the late Eocene - earliest Oligocene, and the middle - late Miocene. With these data we test hypotheses of species migration, phenotypic evolution, as well as the rates of species extinction and speciation in relation to concurrent paleoenvironmental changes during the Cenozoic.

  18. Effect of Fe{sub 2}O{sub 3} in Fe{sub 2}O{sub 3}/AP composite particles on thermal decomposition of AP and on burning rate of the composite propellant

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhenye [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing, 210094 (China); Nanjing University of Technology, Nanjing (China); Li, Fengsheng; Bai, Huaping [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing, 210094 (China)

    2006-12-15

    A technique of composite processing of Fe{sub 2}O{sub 3} and ammonium perchlorate (AP) was employed in making the propellant. The effects of composite processing of Fe{sub 2}O{sub 3} on catalytic activity, on the thermal decomposition of AP, and on the burning rate of the composite propellant were investigated in this paper. Fe{sub 2}O{sub 3}/AP composite particles were prepared by a novel solvent-nonsolvent method. The results show that AP is successfully coated on the surface of Fe{sub 2}O{sub 3}. Composite processing of Fe{sub 2}O{sub 3} and AP can improve the catalytic activity of Fe{sub 2}O{sub 3}. Fe{sub 2}O{sub 3} exhibits better catalytic effect with increasing Fe{sub 2}O{sub 3} content. The larger interface between Fe{sub 2}O{sub 3} and AP and lower density of composite propellant (with the added Fe{sub 2}O{sub 3}/AP composite particles) are responsible for the enhancement of the catalytic activity of Fe{sub 2}O{sub 3}. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  19. The screw propeller

    Science.gov (United States)

    Larrabee, E. E.

    1980-07-01

    Marine and air screw propellers are considered in terms of theoretical hydrodynamics as developed by Joukowsky, Prandtl, and Betz. Attention is given to the flow around wings of finite span where spanwise flow exists and where lift and the bound vorticity must all go smoothly to zero at the wing tips. The concept of a trailing vortex sheet made up of infinitesimal line vortexes roughly aligned with the direction of flight is discussed in this regard. Also considered is induced velocity, which tends to convect the sheet downward at every stage in the roll-up process, the vortex theory of propellers and the Betz-Prandtl circulation distribution. The performance of the Gossamer Albatross and of a pedal-driven biplane called the Chrysalis are also discussed.

  20. 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.

  1. V isotope composition in modern marine hydrothermal sediments

    Science.gov (United States)

    Wu, F.; Owens, J. D.; Nielsen, S.; German, C. R.; Rachel, M.

    2017-12-01

    Vanadium is multivalence transition metal with two isotopes (51V and 50V). Recent work has shown that large V isotope variations occur with oxygen variations in modern sediments (Wu et al., 2016 and 2017 Goldschmidt Abstracts), providing its potential as a promising proxy for determining low oxygen conditions. However, the development of V isotopes as a proxy to probe past redox conditions requires a comprehensive understanding of the modern oceanic isotopic mass balance. Therein, the scavenging of V from the hydrous iron oxides in hydrothermal fluid has been shown to be an important removal process from seawater (Rudnicki and Elderfield, 1993 GCA) but remains unquantified. In this study, we analyzed V isotopic compositions of metalliferous sediments around the active TAG hydrothermal mound from the mid-Atlantic Ridge (26° degrees North) and the Eastern Pacific Zonal Transect (GEOTRACES EPZT cruise GP16). The TAG sediments deposited as Fe oxyhydroxides from plume fall-out, and have δ51V values between -0.3 to 0‰. The good correlation between Fe and V for these metalliferous sediments indicate that the accumulation of V in these samples is directly related to the deposition of Fe oxyhydroxides, which also control their V isotope signature. The EPZT samples cover 8,000 km in the South Pacific Ocean with sedimentary areas that underlie the Peru upwelling region and the well-oxygenated deep South Pacific Ocean influenced by hydtorthermal plume material from southern East Pacific Rise (EPR). The sediments collected at the east of the EPR have δ51V values between -1.2 to -0.7‰, similar to previous δ51V of oxic sediments. In contrast, the sediments from the west of the EPR have δ51V values (-0.4 to 0‰) similar to hydrothermal sediments from the mid-Atlantic Ridge, indicating the long transportation (more than 4,000 km, Fitzsimmons et al., 2017 NG) of Fe and Mn from hydrothermal plume and their incorporation into sediments have a major impact on the cycle of V

  2. TRIGLYCERIDE COMPOSITION OF SIXTEEN STRAINS OF MARINE DIATOM

    Directory of Open Access Journals (Sweden)

    Lily M.G. Panggabean

    2013-07-01

    Full Text Available Trigliceride or triacylglicerol (TAG composition in crude oil of sixteen strain of marine diatom has been detected by spectra analyses on an Electrospray - Ion Trap – Mass Spectrometry (ESI-IT-MS HCT Bruker-Daltonic GmbH instrument with AgNO3 used as coordination ionization agent. Biomass samples of each microalga strain were taken from early and late stationary cultures in f/2 enriched seawater and algal oils were extracted according to Bligh and Dyer. Results from spectra analysis showed that P-Pt-P (C16:0-C16:1-C16:0 were distinguished in TAG from diatom strains Chaetoceros sp.1, Chaetoceros sp.2, Thalasiossira sp.1, Thalasiossira sp.2, Thalasiossira sp.3, Navicula sp. 1, Navicula sp. 2, Navicula sp. 3, Navicula sp. 4, Nitzschia sp. 2 and Amphora sp. In contrast, TAGs in Melosira sp. included P-P-P (C16:0-C16:0-C16:0 and P-P-O (C16:0-C16:0-C18:1 were identified. TAGs from Chaetoceros sp. were the most varies among samples, i.e. P-Pt-P (C16:0-C16:1-C16:0, A-P-M (C20:4-C16:0-C14:0, P-Pt-Lt (C16:0-C16:1-C18:3, P-Pt-A (C16:0-C16:1-C20:4, D-P-P (C22:6-C16:0-C16:0, A-Ln-P (C20:4-C18:2-C16:0. Various TAGs were also detected in Nitzschia sp.2, i.e. P-Pt-M (C16:0-C16:1-C14:0, P-Pt-P (C16:0-C16:1-C16:0, P-Pt-S (C16:0-C16:1-C18:0, P-Pt-A (C16:0-C16:1-C20:4. TAGs composition in Skeletonema strains that similar to those in Nitzschia sp.1 has longer carbon, i.e. P-P-O (C16:0-C16:0-C18:1, P-O-O (C16:0-C18:1-C18:1 and O-O-O (C18:1-C18:1-C18:1. TAGs with longer carbon chain and more double bond including highly unsaturated fatty acid C20:4 were increased with culture age in diatoms Chaetoceros sp.1, Chaetoceros sp.2, Thalasiossira sp.2, Navicula sp.1 and Nitzschia sp. 2.Keywords: diatom, TAG, ESI-IT-MS, f/2, early and late stationary

  3. Influence of fishing activity over the marine debris composition close to coastal jetty.

    Science.gov (United States)

    Farias, Eduardo G G; Preichardt, Paulo R; Dantas, David V

    2018-04-23

    Worldwide, the marine debris emissions have been provoking impacts in ecosystems, generating massive mortality of different species with commercial interest. In South America, we have a lack of studies to verify the marine debris composition in transitional environments such as adjacent regions of coastal jetties. These are hydraulic engineering constructions used to maintain the navigation channel access between the sea-estuarine interface and are also used by teleost fishes, crustaceans, and mollusks like artificial shelters (reefs), being excellent fishing grounds. Therefore, the present study was devoted to qualitatively evaluate the composition of marine debris in an internal jetty portion of a Laguna Estuarine System (LES) located in South America (Brazil). Six hundred freediving were conducted to collect marine debris in the study region. The in situ campaigns were performed in 2016 during all spring season (sand substrata) in four distinct zones with 26,400 m 2 each one covering almost all adjacent jetty extension, to evaluate possible spatial changes in the marine debris composition. All material obtained was identified, measured, weighed, and ordered in eight groups, with six groups being related to the fishing activity and two groups related to the tourism/community in the study region. So, it was possible to observe possible relations between the marine debris distribution to artisanal and recreational local fishing. After 600 freediving sampling efforts, 2142 marine debris items were obtained, totaling close to 100 kg of solid waste removed from the inner portion of the coastal jetty. Notably, 1752 units (50 kg) of fishing leads were collected being this item the main marine debris residue found in the four sampled areas, corresponding to nearly 50% of the total weight of the collected waste. Ninety-eight percent of marine debris were derived from the local fishing activities, and just 2% were derived from tourism/community. Considering the total

  4. Supercritical Fluid Processing of Propellant Polymers

    Science.gov (United States)

    1991-01-01

    of insoluble material present in the polymeric neopentyl glycol azelate (NPGA) binder. Laub (2) summarizes (from Refs 3 & 4) the various polymeric...binders used in composite propellant formulations for DOD missile systems. e.g., these include: polyneopentyl glycol azelate (NPGA) in HAWK. hydroxy...systems. Composite smokeless propellants containing polyethylene glycol (PEG), polyethylene glycol adepate (PEGA) and polycaprolactone are currently under

  5. Lipid Composition Of Two Marine Fishes – Scomber scombrus And ...

    African Journals Online (AJOL)

    Lipids from two species of marine fish – Scomber scombrus and Trachurus trachurus were investigated. Fish oil from Trachurus trachurus had higher oil yield than that of Scomber scombrus. The lipids contain high levels of triacylglycerol 228 – 250 mg%, cholesterol 160 – 235 mg%, and phospholipids 2.2 – 2.4 mg%.

  6. Advanced composites for aerospace, marine, and land applications

    CERN Document Server

    Srivatsan, T; Peretti, Michael

    2016-01-01

    The papers in this volume cover a broad spectrum of topics that represent the truly diverse nature of the field of composite materials. This collection presents research and findings relevant to the latest advances in composites materials, specifically their use in aerospace, maritime, and even land applications. The editors have made every effort to bring together authors who put forth recent advances in their research while concurrently both elaborating on and thereby enhancing our prevailing understanding of the salient aspects related to the science, engineering, and far-reaching technological applications of composite materials.

  7. Perfluoroalkyl acid contamination and polyunsaturated fatty acid composition of French freshwater and marine fishes.

    Science.gov (United States)

    Yamada, Ami; Bemrah, Nawel; Veyrand, Bruno; Pollono, Charles; Merlo, Mathilde; Desvignes, Virginie; Sirot, Véronique; Oseredczuk, Marine; Marchand, Philippe; Cariou, Ronan; Antignac, Jean-Phillippe; Le Bizec, Bruno; Leblanc, Jean-Charles

    2014-07-30

    In this study, French marine and freshwater fish perfluoroalkyl acid (PFAA) contamination are presented along with their fatty acid (FA) composition to provide further elements for a risk/benefit balance of fish consumption to be assessed. The 29 most consumed marine fish species were collected in four metropolitan French coastal areas in 2004 to constitute composite samples. Geographical differences in terms of consumed species and contamination level were taken into account. Three hundred and eighty-seven composite samples corresponding to 16 freshwater fish species collected between 2008 and 2010 in the six major French rivers or their tributaries were selected among the French national agency for water and aquatic environments freshwater fish sample library. The raw edible parts were analyzed for FA composition and PFAA contamination. Results show that freshwater fishes are more contaminated by PFAAs than marine fishes and do not share the same contamination profile. Freshwater fish contamination is mostly driven by perfluorooctane sulfonate (PFOS) (75%), whereas marine fish contamination is split between perfluorooctanoic acid (PFOA) (24%), PFOS (20%), perfluorohexanoic acid (PFHxA) (15%), perfluoropentanoic acid (PFHpA) (11%), and perfluorobutanoic acid (PFBA) (11%). Common carp, pike-perch, European perch, thicklip grey mullet, and common roach presented the most unfavorable balance profile due to their high level of PFAAs and low level of n-3 long-chain polyunsaturated fatty acids (LC-PUFAs). These data could be used, if needed, in an updated opinion on fish consumption that takes into account PFAA contamination.

  8. Sponge species composition, abundance, and cover in marine lakes and coastal mangroves in Berau, Indonesia

    NARCIS (Netherlands)

    Becking, L.E.; Cleary, D.F.R.; Voogd, de N.J.

    2013-01-01

    We compared the species composition, abundance, and cover of sponges in 2 marine lakes (Kakaban Lake and Haji Buang Lake) and adjacent coastal mangroves on the islands of Kakaban and Maratua in the Berau region of Indonesia. We recorded a total of 115 sponge species, 33 of which were restricted to

  9. 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...... simulations for a propeller with a hull model have showed acceptable agreement with a model test result in the thrust and torque (Larsson et al. 2010). In the current work, a measured hull wake is applied to the simulation instead of modelling a hull, because the hull geometry is mostly not available...... for propeller designers and the computational effort can be reduced by excluding the hull. The CFD simulation of a propeller flow with a hull wake is verified in order to use CFD as a propeller design tool. A Kappel propeller, which is an innovative tip-modified propeller, is handled. Kappel propellers...

  10. Resource limitation and the biochemical composition of marine phytoplankton

    NARCIS (Netherlands)

    Grosse, J.

    2016-01-01

    The aim of the work presented in this thesis was to determine the effects of nutrient availability on the biomolecule composition and synthesis in North Sea phytoplankton. Nutrient availability in coastal seas has changed substantially over the past decades due to anthropogenic activities. Riverine

  11. Development of hydrazinium nitroformate based solid propellants

    NARCIS (Netherlands)

    Schöyer, H.F.R.; Schnorhk, A.J.; Korting, P.A.O.G.; Lit, P.J. van; Mul, J.M.; Gadiot, G.; Meulenbrugge, J.J.

    1995-01-01

    The development of new high-performance propellant combinations requires the establishment of safety and handling characteristics and thermodynamic decomposition and explosive properties. This paper addresses the early development phases of a new composite solid propellant based on HNF as oxidizer

  12. Seasonal trends in abundance and composition of marine debris in selected public beaches in Peninsular Malaysia

    Science.gov (United States)

    Mobilik, Julyus-Melvin; Ling, Teck-Yee; Husain, Mohd-Lokman Bin; Hassan, Ruhana

    2015-09-01

    The abundance and composition of marine debris were investigated at Saujana (in the state of Negeri Sembilan) and Batu Rakit (in the state of Terengganu) beaches during surveys conducted in December 2012 (northeast monsoon), May 2013 (intermediate monsoon) and July 2013 (southwest monsoon). A total of 4,682 items of debris weighing 231.4 kg were collected and sorted. Batu Rakit received substantially greater quantities of debris (815±717 items/km or 40.4±13.0 kg/km) compared to Saujana (745±444 items/km or 36.7±18.0 kg/km). Total debris item was more abundant during the southwest monsoon (SWM) (1,122±737 items/km) compared to the northeast monsoon (NEM) (825±593 items/ km) and the intermediate monsoon (IM) (394±4 items/km) seasons. Plastic category (88%) was the most numerous items collected and object items contributed 44.18% includes packaging, plastic fragments, cups, plastic shopping bags, plastic food wrapper, clear plastic bottles from the total debris items collected. Object items associated with common source (47%) were the highest debris accumulated, followed by terrestrial (30%) and marine (23%) sources. The high percentage of common and terrestrial sources during SWM season requires immediate action by marine environment stakeholders to develop and introduce strategies to reduce if not totally eliminates the marine debris in the marine environment. Awareness should be continued and focused on beach users and vessels' crew to alert them on the alarming accumulation rate of marine debris and its pathways into the marine environment.

  13. Influence of dispersing additives and blend composition on stability of marine high-viscosity fuels

    Directory of Open Access Journals (Sweden)

    Т. Н. Митусова

    2017-12-01

    Full Text Available The article offers a definition of the stability of marine high-viscosity fuel from the point of view of the colloid-chemical concept of oil dispersed systems. The necessity and importance of the inclusion in the current regulatory requirements of this quality parameter of high-viscosity marine fuel is indicated. The objects of the research are high-viscosity marine fuels, the basic components of which are heavy oil residues: fuel oil that is the atmospheric residue of oil refining and viscosity breaking residue that is the product of light thermal cracking of fuel oil. As a thinning agent or distillate component, a light gas oil was taken from the catalytic cracking unit. The stability of the obtained samples was determined through the xylene equivalent index, which characterizes the stability of marine high-viscosity fuel to lamination during storage, transportation and operation processes. To improve performance, the resulting base compositions of high-viscosity marine fuels were modified by introducing small concentrations (0.05 % by weight of stabilizing additives based on oxyethylated amines of domestic origin and alkyl naphthalenes of foreign origin.

  14. Development of improved lacv-30 propeller blade coatings for protection against sand and rain erosion and marine environment corrosion. Final report 4 Jan 1982-4 Mar 1983

    Energy Technology Data Exchange (ETDEWEB)

    Malone, G.A.

    1983-05-10

    An investigation was conducted of candidate systems offering potential erosion and corrosion protection when applied as coatings to Aluminum 7075 alloy propeller blades used to propel air cushioned vehicles operating in severe environments. This work focused on (1) special hard anodized and (2) hard nickel electroplated coatings as candidate protective systems with sand/rain erosion testing to evaluate their merits. Attributes of the coating systems developed and studied included: For (1) Ways and means to produce and control deposit hardness for optimum erosion resistance, methods of bonding to blades for high integrity adhesion, and inclusion of sacrificial corrosion protection electroplates in the coating systems (zinc and zinc-nickel alloy). For (2) Incorporation of dry film lubricant systems on sealed hardcoats of various anodic coating thicknesses to enhance erosion performance. Study results indicated that anodized coatings did not provide suitable erosion protection to Aluminum 7075 in sand/rain environments, even with dry film lubricant supplemental films. Electroplated hard nickel coatings, Vickers hardnesses in the range of 380 to 440, appeared better for combined sand/rain erosion resistance based on comparisons with prior work. Dilute phosphoric anodizing the aluminum substrates led to excellent bonds and improved corrosion resistance when subsequently plated with ductile nickel from a low pH bath, followed by hard nickel electroplate.

  15. Geochemical and geological constraints on the composition of marine sediment pore fluid: Possible link to gas hydrate deposits

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumdar, A.; Joao, H.M.; Peketi, A.; Dewangan, P.; Kocherla, M.; Joshi, R.K.; Ramprasad, T.

    Pore water sulfate consumption in marine sediments is controlled by microbially driven sulfate reduction via organo-clastic and methane oxidation processes. In this work, we present sediment pore fluid compositions of 10 long sediment cores and high...

  16. Biogeochemical interactions control a temporal succession in the elemental composition of marine communities

    KAUST Repository

    Martiny, Adam C.; Talarmin, Agathe Anne Gaelle; Mouginot, Cé line; Lee, Jeanette A.; Huang, Jeremy S.; Gellene, Alyssa G.; Caron, David A.

    2015-01-01

    Recent studies have revealed clear regional differences in the particulate organic matter composition and stoichiometry of plankton communities. In contrast, less is known about potential mechanisms and patterns of temporal changes in the elemental composition of marine systems. Here, we monitored weekly changes in environmental conditions, phytoplankton abundances, and particulate organic carbon, nitrogen, and phosphorus concentrations over a 3-yr period. We found that variation in the particulate organic matter (POM) concentrations and ratios were related to seasonal oscillations of environmental conditions and phytoplankton abundances. Periods with low temperature, high nutrient concentrations and a dominance of large phytoplankton corresponded to low C : N : P and vice-versa for warmer periods during the summer and fall. In addition to seasonal changes, we observed a multiyear increase in POM C : P and N : P that might be associated with the Pacific Decadal Oscillation. Finally, there was substantial short-term variability in all factors but similar linkages between environmental variability and elemental composition as observed on seasonal and interannual time-scales. Using a feed-forward neural network, we could explain a large part of the variation in POM concentrations and ratios based on changes in environmental conditions and phytoplankton abundances. The apparent links across all time-scales between changes in physics, chemistry, phytoplankton, and POM concentrations and ratios suggest we have identified key controls of the elemental composition of marine communities in this region.

  17. Properties Variation of Carbon Fiber Reinforced Composite for Marine Current Turbine in Seawater

    Directory of Open Access Journals (Sweden)

    Li Jing

    2016-01-01

    Full Text Available Turbine blade which are generally made of composite is a core device among components of tidal current power generator that converts the flow of tidal current into a turning force. Recent years, damages of composite turbine blades have been reported due to reasons like seawater degradation, lake of strength, manufacture etc. In this paper, water absorption, tensile, bending, longitudinal transverse shearing properties of carbon fiber reinforced plastic (CRP composite which would be applied to fabricate the marine current turbine blade has been investigated. Furthermore, the variations of properties with seawater immersion period were studied. The results indicated that the water absorption increased almost linearly at the beginning of immersion and then became stable. Tensile strength of specimen tended to decrease firstly and then recovered slightly. However, the longitudinal transverse shearing strength showed reverse variation trend comparing to tensile strength. And the bending property of specimens was depressed significantly. The properties variations in seawater shall be referenced to design and fabrication of composite marine current turbine blade.

  18. Biogeochemical interactions control a temporal succession in the elemental composition of marine communities

    KAUST Repository

    Martiny, Adam C.

    2015-11-23

    Recent studies have revealed clear regional differences in the particulate organic matter composition and stoichiometry of plankton communities. In contrast, less is known about potential mechanisms and patterns of temporal changes in the elemental composition of marine systems. Here, we monitored weekly changes in environmental conditions, phytoplankton abundances, and particulate organic carbon, nitrogen, and phosphorus concentrations over a 3-yr period. We found that variation in the particulate organic matter (POM) concentrations and ratios were related to seasonal oscillations of environmental conditions and phytoplankton abundances. Periods with low temperature, high nutrient concentrations and a dominance of large phytoplankton corresponded to low C : N : P and vice-versa for warmer periods during the summer and fall. In addition to seasonal changes, we observed a multiyear increase in POM C : P and N : P that might be associated with the Pacific Decadal Oscillation. Finally, there was substantial short-term variability in all factors but similar linkages between environmental variability and elemental composition as observed on seasonal and interannual time-scales. Using a feed-forward neural network, we could explain a large part of the variation in POM concentrations and ratios based on changes in environmental conditions and phytoplankton abundances. The apparent links across all time-scales between changes in physics, chemistry, phytoplankton, and POM concentrations and ratios suggest we have identified key controls of the elemental composition of marine communities in this region.

  19. 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....

  20. Mandibular gnathobases of marine planktonic copepods – feeding tools with complex micro- and nanoscale composite architectures

    Directory of Open Access Journals (Sweden)

    Jan Michels

    2015-03-01

    Full Text Available Copepods are dominant members of the marine zooplankton. Their diets often comprise large proportions of diatom taxa whose silicified frustules are mechanically stable and offer protection against grazers. Despite of this protection, many copepod species are able to efficiently break even the most stable frustule types. This ability requires specific feeding tools with mechanically adapted architectures, compositions and properties. When ingesting food, the copepods use the gnathobases of their mandibles to grab and, if necessary, crush and mince the food items. The morphology of these gnathobases is related to the diets of the copepods. Gnathobases of copepod species that mainly feed on phytoplankton feature compact and stable tooth-like structures, so-called teeth. In several copepod species these gnathobase teeth have been found to contain silica. Recent studies revealed that the siliceous teeth are complex microscale composites with silica-containing cap-like structures located on chitinous exoskeleton sockets that are connected with rubber-like bearings formed by structures with high proportions of the soft and elastic protein resilin. In addition, the silica-containing cap-like structures exhibit a nanoscale composite architecture. They contain some amorphous silica and large proportions of the crystalline silica type α-cristobalite and are pervaded by a fine chitinous fibre network that very likely serves as a scaffold during the silicification process. All these intricate composite structures are assumed to be the result of a coevolution between the copepod gnathobases and diatom frustules in an evolutionary arms race. The composites very likely increase both the performance of the siliceous teeth and their resistance to mechanical damage, and it is conceivable that their development has favoured the copepods’ dominance of the marine zooplankton observed today.

  1. Sources and composition of submicron organic mass in marine aerosol particles

    Science.gov (United States)

    Frossard, Amanda A.; Russell, Lynn M.; Burrows, Susannah M.; Elliott, Scott M.; Bates, Timothy S.; Quinn, Patricia K.

    2014-11-01

    The sources and composition of atmospheric marine aerosol particles (aMA) have been investigated with a range of physical and chemical measurements from open-ocean research cruises. This study uses the characteristic functional group composition (from Fourier transform infrared spectroscopy) of aMA from five ocean regions to show the following: (i) The organic functional group composition of aMA that can be identified as mainly atmospheric primary marine (ocean derived) aerosol particles (aPMA) is 65 ± 12% hydroxyl, 21 ± 9% alkane, 6 ± 6% amine, and 7 ± 8% carboxylic acid functional groups. Contributions from photochemical reactions add carboxylic acid groups (15%-25%), shipping effluent in seawater and ship emissions add additional alkane groups (up to 70%), and coastal or continental emissions mix in alkane and carboxylic acid groups. (ii) The organic composition of aPMA is nearly identical to model-generated primary marine aerosol particles from bubbled seawater (gPMA, which has 55 ± 14% hydroxyl, 32 ± 14% alkane, and 13 ± 3% amine functional groups), indicating that its overall functional group composition is the direct consequence of the organic constituents of the seawater source. (iii) While the seawater organic functional group composition was nearly invariant across all three ocean regions studied and the ratio of organic carbon to sodium (OC/Na+) in the gPMA remained nearly constant over a broad range of chlorophyll a concentrations, the gPMA alkane group fraction appeared to increase with chlorophyll a concentrations (r = 0.66). gPMA from productive seawater had a larger fraction of alkane functional groups (42 ± 9%) compared to gPMA from nonproductive seawater (22 ± 10%), perhaps due to the presence of surfactants in productive seawater that stabilize the bubble film and lead to preferential drainage of the more soluble (lower alkane group fraction) organic components. gPMA has a hydroxyl group absorption peak location characteristic of

  2. Contrasting Cloud Composition Between Coupled and Decoupled Marine Boundary Layer Clouds

    Science.gov (United States)

    WANG, Z.; Mora, M.; Dadashazar, H.; MacDonald, A.; Crosbie, E.; Bates, K. H.; Coggon, M. M.; Craven, J. S.; Xian, P.; Campbell, J. R.; AzadiAghdam, M.; Woods, R. K.; Jonsson, H.; Flagan, R. C.; Seinfeld, J.; Sorooshian, A.

    2016-12-01

    Marine stratocumulus clouds often become decoupled from the vertical layer immediately above the ocean surface. This study contrasts cloud chemical composition between coupled and decoupled marine stratocumulus clouds. Cloud water and droplet residual particle composition were measured in clouds off the California coast during three airborne experiments in July-August of separate years (E-PEACE 2011, NiCE 2013, BOAS 2015). Decoupled clouds exhibited significantly lower overall mass concentrations in both cloud water and droplet residual particles, consistent with reduced cloud droplet number concentration and sub-cloud aerosol (Dp > 100 nm) number concentration, owing to detachment from surface sources. Non-refractory sub-micrometer aerosol measurements show that coupled clouds exhibit higher sulfate mass fractions in droplet residual particles, owing to more abundant precursor emissions from the ocean and ships. Consequently, decoupled clouds exhibited higher mass fractions of organics, nitrate, and ammonium in droplet residual particles, owing to effects of long-range transport from more distant sources. Total cloud water mass concentration in coupled clouds was dominated by sodium and chloride, and their mass fractions and concentrations exceeded those in decoupled clouds. Conversely, with the exception of sea salt constituents (e.g., Cl, Na, Mg, K), cloud water mass fractions of all species examined were higher in decoupled clouds relative to coupled clouds. These results suggest that an important variable is the extent to which clouds are coupled to the surface layer when interpreting microphysical data relevant to clouds and aerosol particles.

  3. [Fatty acid composition of edible marine fish in Zhoushan, Zhejiang province].

    Science.gov (United States)

    Gao, Yi-xiong; Yue, Bing; Yu, Xin-wei; He, Jia-lu; Shang, Xiao-hong; Li, Xiao-wei; Wu, Yong-ning

    2013-06-01

    To analyze the main fatty acids in edible marine fish from Zhoushan, Zhejiang province. From September to October 2011, a total of 186 edible marine fish (31 species,6 individual fishes/species) were collected in local markets. Total lipids of edible part were extracted by Folch's method and fatty acids were separated and quantified by gas chromatographic after the homogenization of edible part. The differences of composition of n-6 polyunsaturated fatty acid (n-6 PUFA), n-3 polyunsaturated fatty acid (n-3 PUFA),saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) among fishes were analyzed. Among the 31 fishes, total lipids were highest in Auxis thazard ((13.2 ± 1.2)g/100 g edible part) and lowest in Thamnaconus modestus ((0.6 ± 0.1)g/100 g edible part). Total n-6 PUFA were highest in Mugil cephalus ((875.7 ± 506.4)mg/100 g edible part) and lowest in Seriola quinqueradiata((2.1 ± 1.9)mg/100 g edible part). Total n-3 PUFA were highest in Auxis thazard ((2623.8 ± 426.1)mg/100 g edible part) and lowest in Scoliodon sorrakowah ((82.0 ± 13.9)mg/100 g edible part). SFA were highest in Trachinotus ovatus((3014.9 ± 379.0)mg/100 g edible part) and lowest in Seriola quinqueradiata ((89.7 ± 5.8)mg/100 g edible part). MUFA were highest in Coilia nasus ((3335.7 ± 383.5)mg/100 g edible part) and lowest in Thamnaconus modestus ((32.1 ± 16.9)mg/100 g edible part). There were significant differences of composition of total lipids and of fatty acids among 31 edible marine fish species from Zhoushan.

  4. Biosorption of copper by marine algae Gelidium and algal composite material in a packed bed column.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Loureiro, José M; Boaventura, Rui A R

    2008-09-01

    Marine algae Gelidium and algal composite material were investigated for the continuous removal of Cu(II) from aqueous solution in a packed bed column. The biosorption behaviour was studied during one sorption-desorption cycle of Cu(II) in the flow through column fed with 50 and 25 mg l(-1) of Cu(II) in aqueous solution, at pH 5.3, leading to a maximum uptake capacity of approximately 13 and 3 mg g(-1), respectively, for algae Gelidium and composite material. The breakthrough time decreases as the inlet copper concentration increases, for the same flow rate. The pH of the effluent decreases over the breakthrough time of copper ions, which indicates that ion exchange is one of the mechanisms involved in the biosorption process. Temperature has little influence on the metal uptake capacity and the increase of the ionic strength reduces the sorption capacity, decreasing the breakthrough time. Desorption using 0.1M HNO(3) solution was 100% effective. After two consecutive sorption-desorption cycles no changes in the uptake capacity of the composite material were observed. A mass transfer model including film and intraparticle resistances, and the equilibrium relationship, for adsorption and desorption, was successfully applied for the simulation of the biosorption column performance.

  5. Study of the carbon and oxygen isotopic compositions in marine shells of Salvador-Bahia, Brazil

    International Nuclear Information System (INIS)

    Freitas, J.C.B. de.

    1977-01-01

    The carbon and oxygen isotopic composition of 68 samples of marine shells from the region of Salvador was determined. These samples are from points on the open coast and in the interior of the Todos os Santos Bay and they are composed in part by recent specimens and in part by old specimens taken from Quaternary sediments. The results for δ 18 O are in the range of -2,83per mille to + 1,21per mille (PDB) and for δ 13 C in the range of -3,10per mille to +2,63per mille (PDB). The reults for the recent shells from the interior of the Todos os Santos Bay show variations in the δ 13 C values associated to the dominance of organic matter in some regions. For the old samoles, gathered in te variations in the δ 13 C values was associated to the existence in points of that region of deposits of fluvio-lagunar sediments, originated during the last marine transgression. It was identified, for a few species with the same age and location, the effect of biological fractionations. Nevertheless, the observed dominant factor on the isotopic differentiation was the environmental fractionation. (Author) [pt

  6. Retrospective analysis of diversity and species composition of marine macroalgae of Hainan Island (China)

    Science.gov (United States)

    Titlyanov, Eduard A.; Titlyanova, Tamara V.; Xia, Bangmei; Bartsch, Inka

    2016-09-01

    Retrospective analysis of diversity and species composition of marine macroalgae of Hainan Island in the period 1933-1992 is presented in this paper. There are two extensive sample collection periods of benthic macroalgae: the early collection (EC) covers a period between the early 1930s and the 1980s before considerable urbanization and reef degradation took place and a late collection (LC) was performed in 1990/1992 during a phase of rapid urbanization. Analysis of data also including an earlier published inventory of green algae covering the same collection sites (Titlyanov et al. 2011a) revealed that the marine flora of the island comprises 426 taxa in total, with 59% red algae, 18% brown algae and 23% green algae. In total 59 species of red algae, 11 species of brown algae and 37 species of green algae sampled during the LC are new records for Hainan Island. Considerable floristic changes between EC and LC became evident. In the LC there were significantly more filamentous, tubular or fine blade-like, and often epiphytic, green and red algae with a high surface-to-volume ratio. Additionally a reduction of green, brown and red algal species with larger fleshy or foliose thalli and a low surface-to-volume ratio was observed. It is assumed that the changes reflect the degradation of the coral reef ecosystem around Hainan, which was damaged by human activities especially in the 1950s-1970s.

  7. The nutritional nexus: linking niche, habitat variability and prey composition in a generalist marine predator.

    Science.gov (United States)

    Machovsky-Capuska, Gabriel E; Miller, Mark G R; Silva, Fabiola R O; Amiot, Christophe; Stockin, Karen A; Senior, Alistair M; Schuckard, Rob; Melville, David; Raubenheimer, David

    2018-06-05

    1.Our understanding of the niche concept will remain limited while the quantity and range of different food types eaten remains a dominant proxy for niche breadth, as this does not account for the broad ecological context that governs diet. Linking nutrition, physiology and behaviour are critical to predict the extent to which a species adjusts its nutritional niche breadth at the levels of prey ("prey composition niche", defined as the range of prey compositions eaten), and diet ("realized nutritional niche" is the range of diets composed through feeding on the prey). 2.Here we studied adult-chick rearing Australasian gannets (Morus serrator) to propose an integrative approach using sea surface temperature anomalies (SSTa), geographic location and bathymetry over different years, to explore their relationship with the nutritional composition of prey and diets (i.e., prey composition and nutritional niche breadth), habitat use and foraging behavior. 3.We found that gannets feed on prey that varied widely in their nutritional composition (have a broad prey composition niche), and composed diets from these prey that likewise varied in composition (have a broad realized nutritional niche), suggesting generalism at two levels of macronutrient selection. 4.Across seasons, we established "nutritional landscapes" (hereafter nutriscapes), linking the nutritional content of prey (wet mass protein to-lipid ratio -P:L-) to the most likely geographic area of capture and bathymetry. Nutriscapes varied in their P:L from 6.06 to 15.28, over time, space and bathymetry (0 to 150 m). 5.During warm water events (strong positive SSTa), gannets expanded their foraging habitat, increased their foraging trip duration and consumed prey and diets with low macronutrient content (wet mass proportions of P and L). They were also constrained to the smallest prey composition and realized nutritional niche breadths. 6.Our findings are consistent with previous suggestions that dietary generalism

  8. Seasonal variation in the composition and concentration of butyltin compounds in marine fish of Taiwan

    International Nuclear Information System (INIS)

    Dong, C.D.; Chen, C.W.; Liu, L.L.

    2004-01-01

    For the first time, strong evidence is presented to demonstrate that the accumulations of butyltin compounds (BTs) exhibit seasonal variations with respect to their compositions and concentrations in marine fishes. Measurements were made on the benthic ponyfish Leiogenathus splendens and lizardfish Trachinocephalus myops inhabiting the west coast of Taiwan. In the whole body samples of the ponyfish, BT concentrations ranged from 236 to 2501 ng/g wet wt, with those in winter considerably higher than in the other seasons (p summer > spring (p<0.05). Meanwhile, TBT (41%) was predominant in spring, whereas DBT (50 and 68%) was most heavily concentrated in summer and autumn (p<0.001). Seasonally mediated physiological changes, such as dilution due to growth and metabolic compensation, may play important roles in forming different BT accumulation patterns among seasons and organisms

  9. Elemental composition by EDXRF of marine sponges from the Berlengas portuguese natural park - western portuguese coast

    International Nuclear Information System (INIS)

    Araujo, Maria Fatima; Conceicao, Ana; Barbosa, Teresa

    2001-01-01

    Marine sponges are sedentary and unselective filter-feeding metazoans, which are nowadays represented by more than six thousand species with the Demospongiae being the most representative, inhabiting all aquatic environments. Due to their way of feeding, by filtering large amounts of water, these benthic organisms are particularly exposed to pollutants. Previous studies have demonstrated their aptitude in being used as environmental monitors. Besides, some authors have evidenced a selective bio-accumulation capability for some transition elements (e.g. Ni, Zn) which is dependent on the species. The present work aims at the investigation of marine sponges collected at the Berlengas Islands located at Western Portuguese Coastal area. These islands constitute a National Park with controlled access and low signal of anthropogenic influences, being a nearly ideal habitat to evaluate a possible selective bio-accumulation. Thirty-five sponges collected in August 1998, at the Berlengas National Park were classified and analysed by Energy-Dispersive X-Ray Fluorescence Spectrometry (EDXRF). The major, minor and some trace elements: Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, I and Pb were determined. Besides, sediment samples were also taken from the area to assess some lithological influence on the sponge composition. Due to the high percentage of elements that do not emit characteristic X-ray lines, absorption corrections for quantitative calculations were carried out taking into account the ratio between the inelastic and elastic scattered incident radiation of compounds and standard reference materials, from a silver secondary target. A lithological influence on the sponge major elemental composition is demonstrated. The absence of any trace metal contamination was confirmed and a clear selective bio-accumulation in some trace elements, such as Ni, Zn and As was detected

  10. Community composition, structure, and interrelationships in the marine intertidal Endocladia muricata – Balanus glandula association in Monterey Bay, California

    NARCIS (Netherlands)

    Glynn, Peter W.

    1965-01-01

    Studies of the community composition, structure and species interrelationships of the Endocladia-Balanus association were carried out on the rocky shores at the Hopkins Marine Station, Pacific Grove, California, over the period 1959—1961. The organisms making up this biotic association form a

  11. Factors that control the stable carbon isotopic composition of methane produced in an anoxic marine sediment

    Science.gov (United States)

    Alperin, M. J.; Blair, Neal E.; Albert, D. B.; Hoehler, T. M.; Martens, C. S.

    1993-01-01

    The carbon isotopic composition of methane produced in anoxic marine sediment is controlled by four factors: (1) the pathway of methane formation, (2) the isotopic composition of the methanogenic precursors, (3) the isotope fractionation factors for methane production, and (4) the isotope fractionation associated with methane oxidation. The importance of each factor was evaluated by monitoring stable carbon isotope ratios in methane produced by a sediment microcosm. Methane did not accumulate during the initial 42-day period when sediment contained sulfate, indicating little methane production from 'noncompetitive' substrates. Following sulfate depletion, methane accumulation proceeded in three distinct phases. First, CO2 reduction was the dominant methanogenic pathway and the isotopic composition of the methane produced ranged from -80 to -94 per thousand. The acetate concentration increased during this phase, suggesting that acetoclastic methanogenic bacteria were unable to keep pace with acetate production. Second, acetate fermentation became the dominant methanogenic pathway as bacteria responded to elevated acetate concentrations. The methane produced during this phase was progressively enriched in C-13, reaching a maximum delta(C-13) value of -42 per thousand. Third, the acetate pool experienced a precipitous decline from greater than 5 mM to less than 20 micro-M and methane production was again dominated by CO2 reduction. The delta(C-13) of methane produced during this final phase ranged from -46 to -58 per thousand. Methane oxidation concurrent with methane production was detected throughout the period of methane accumulation, at rates equivalent to 1 to 8 percent of the gross methane production rate. Thus methane oxidation was too slow to have significantly modified the isotopic signature of methane. A comparison of microcosm and field data suggests that similar microbial interactions may control seasonal variability in the isotopic composition of methane

  12. Inter-Batch Variation and the Effect of Casting Vacuum on Ballistic and Mechanical Properties of a High Performing Cast Composite Rocket Propellant

    Science.gov (United States)

    2014-12-01

    X 5 mm with a bandsaw. Longitudinal faces were coated (inhibited) with an epoxy resin and burned in a Crawford-type low pressure strand burner. The...batch (P0190) is the highest. For strain at maximum stress and strain at break the trend is reversed with the highest values for P0188 and lowest...Appendix A: Propellant Strand Burn Results Table A1: Low pressure strand burn results for P0188, full vacuum coated with epoxy R180/H180

  13. Biofouling community composition across a range of environmental conditions and geographical locations suitable for floating marine renewable energy generation.

    Science.gov (United States)

    Macleod, Adrian K; Stanley, Michele S; Day, John G; Cook, Elizabeth J

    2016-01-01

    Knowledge of biofouling typical of marine structures is essential for engineers to define appropriate loading criteria in addition to informing other stakeholders about the ecological implications of creating novel artificial environments. There is a lack of information regarding biofouling community composition (including weight and density characteristics) on floating structures associated with future marine renewable energy generation technologies. A network of navigation buoys were identified across a range of geographical areas, environmental conditions (tidal flow speed, temperature and salinity), and deployment durations suitable for future developments. Despite the perceived importance of environmental and temporal factors, geographical location explained the greatest proportion of the observed variation in community composition, emphasising the importance of considering geography when assessing the impact of biofouling on device functioning and associated ecology. The principal taxa associated with variation in biofouling community composition were mussels (Mytilus edulis), which were also important when determining loading criteria.

  14. Hydrodynamics of Ship Propellers

    DEFF Research Database (Denmark)

    Breslin, John P.; Andersen, Poul

    This book deals with flows over propellers operating behind ships, and the hydrodynamic forces and moments which the propeller generates on the shaft and on the ship hull.The first part of the text is devoted to fundamentals of the flow about hydrofoil sections (with and without cavitation...... 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...

  15. Lead isotopic composition of paleozoic and late proterozoic marine carbonate rocks in the vicinity of Yucca Mountains, Nevada

    International Nuclear Information System (INIS)

    Zartman, R.E.; Kwak, L.M.

    1993-01-01

    Paleozoic and Late Proterozoic marine carbonate rocks (limestones, dolomites, and their metamorphic equivalents) cropping out in the vicinity of Yucca Mountain contain lead with an isotopic composition strongly suggesting them to be a major source of the lead observed at Trench 14 in the carbonate phase of carbonate-silica veins and nearby surficial calcrete deposits. Six whole-rock samples of marine carbonate rocks yield 206 Pb/ 204 Pb = 19.21-29.06, 207 Pb/ 204 Pb = 15.74-16.01, and 208 Pb/ 204 Pb = 37.90-39.25, and leachate and residue fractions of the rocks reveal additional isotopic heterogeneity within individual samples. Two samples of eolian dust also have isotopic compositions lying along a 'carbonate' to 'silicate' mixing trend that appears to arise entirely from pedeogenic processes. The tendency for the marine carbonate rocks to evolve highly uranogenic, but not thorogenic, lead results in a distinctive isotopic composition that serves as a tracer in eolian dust and secondary carbonate minerals derived from the marine carbonate rocks

  16. 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...

  17. Solid propellant impact tests

    International Nuclear Information System (INIS)

    Snow, E.C.

    1976-03-01

    Future space missions, as in the past, call for the continued use of radioisotopes as heat sources for thermoelectric power generators. In an effort to minimize the risk of radioactive contamination of the environment, a complete safety analysis of each such system is necessary. As a part of these analyses, the effects on such a system of a solid propellant fire environment resulting from a catastrophic launch pad abort must be considered. Several impact tests were conducted in which either a simulant MHW-FSA or a steel ball was dropped on the cold, unignited or the hot, burning surface of a block of UTP-3001 solid propellant. The rebound velocities were measured for both surface conditions of the propellant. The resulting coefficient of restitution, determined as the ratio of the components of the impact and rebound velocities perpendicular to the impact surface of the propellant, were not very dependent on whether the surface was cold or hot at the time of impact

  18. 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...

  19. Disposal of Liquid Propellants

    Science.gov (United States)

    1990-03-13

    propellant includes an oxi- dizer (hydroxylammoniuin nitrate), a fuel (triethanolammonium nitrate), and water . In an- ticipation of widespread (both...are also included. 20. DISTRIBUTION/ AVAILABILIT ’." OF ABMTRACT 21 ABSTRACT SECURITY CLASSIF.CATICIN IUNCLASSIFIEDIUNLIMITED 0 SAME AS RPT. 0 OTIC...trieth- anolammoiur nitrate), anG water . In anticipation of widespread (both conti- nental U.S. and abroac) use of the propellant, USATHAMA began a

  20. Impact of Anthracene Exposure on Bacterial Community Composition and Function in an Egyptian Marine Environment

    International Nuclear Information System (INIS)

    Zakaria, A.E.M.; Lappin-Scott, H.

    2013-01-01

    The application of bioremediation technology for pollution treatment requires more knowledge about how do microbial communities respond to pollutant exposure. The main goals of this study are to investigate the behavior of natural bacterial microflora of Suez Gulf (SGM) in response to exposure to different concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) for different periods. In this study, anthracene, as a model of (PAHs) was added in different concentrations, (30,150 and 500 ppm) to fertilized Suez Gulf water in shaking microcosms to examine the possible shifts in bacterial community composition and function. Changes in bacterial community composition was followed up after different periods of exposure (0, 6, 12, and 18) days to the above mentioned concentrations of anthracene by profiling the amplified product of 16S rDNA via denaturing gradient gel electrophoresis (DGGE) of SGM in treated microcosm separately. DGGE profiles revealed remarkable changes in diversity due to exposure concentration and duration to anthracene. A diverse relationship between anthracene concentration and bacterial diversity was detected. On the other hand, changes in community function were determined by testing the biodegradation capabilities of the consortia after different exposures separately in microcosms containing 50 ppm of anthracene for 14 days. The remaining anthracene was extracted and monitored by high performance liquid chromatography (HPLC) and DGGE profiles of amplified 16S rDNA extracted from parallel biodegradation microcosms were examined to indicate the effects of pre-exposure to different concentrations for different periods to PAHs on the bacterial community compositions. The results confirm that the long term effects of pre exposure to high concentrations of PAH on the bacterial community composition, suggesting that that some organisms can be used as a bio marker indicating the exposures of the marine environment to high concentrations of PAHs. HPLC

  1. Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna.

    Directory of Open Access Journals (Sweden)

    Sabine Rech

    Full Text Available Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas and the Australian barnacle (Austrominius modestus. The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a

  2. Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna

    Science.gov (United States)

    Borrell Pichs, Yaisel J.; García-Vazquez, Eva

    2018-01-01

    Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports) and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas) and the Australian barnacle (Austrominius modestus). The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a much more diverse

  3. Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna.

    Science.gov (United States)

    Rech, Sabine; Borrell Pichs, Yaisel J; García-Vazquez, Eva

    2018-01-01

    Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports) and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas) and the Australian barnacle (Austrominius modestus). The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a much more diverse

  4. Differences in composition of shallow-water marine benthic communities associated with two ophiolitic rock substrata

    Science.gov (United States)

    Bavestrello, Giorgio; Bo, Marzia; Betti, Federico; Canessa, Martina; Gaggero, Laura; Rindi, Fabio; Cattaneo-Vietti, Riccardo

    2018-01-01

    On marine rocky shores, several physical, chemical and biological processes operate to maintain the benthic assemblages' heterogeneity, but among the abiotic factors, the composition and texture of the rocky substrata have been only sporadically considered. However, biomineralogical studies have demonstrated an unsuspected ability of the benthic organisms to interact at different levels with rocky substrata. Therefore, the mineralogy of the substratum can affect the structure of benthic communities. To evaluate this hypothesis, the macrobenthic assemblages developed on two different ophiolitic rocks (serpentinites and metagabbros) in contact at a restricted stretch of the western Ligurian Riviera (western Mediterranean Sea), with identical environmental and climatic conditions, were analysed. Samplings were carried out at four bathymetric levels (+1m, 0m, -1m, and -3m respect to the mean sea level) and the analysis of the data evidenced differences in terms of species distribution and percent coverage. Algal communities growing on metagabbros were poorer in species richness and showed a much simpler structure when compared to the assemblages occurring on the serpentinites. The most widely distributed animal organism, the barnacle Chthamalus stellatus, was dominant on serpentinites, and virtually absent on metagabbros. Our results suggest a complex pattern of interactions between lithology and benthic organisms operating through processes of inhibition/facilitation related to the mineral properties of the substratum.

  5. Effect of frying, grilling, and steaming on amino acid composition of marine fishes.

    Science.gov (United States)

    Erkan, Nuray; Özden, Özkan; Selçuk, Arif

    2010-12-01

    Amino acid and proximate compositions were determined in six raw and cooked marine fish species that are commonly consumed in Turkey. The changes in amino acid and proximate content were found to be significant for all cooking methods in all fish species. Cooking did, in general, significantly increase the contents of essential, semiessential, and other amino acids compared with raw fish species. Grilled Atlantic bonito, anchovy, and bluefish and fried mullet and hake appeared to be more valuable fish dishes for obtaining the officially recommended appropriate daily intake of essential amino acids for humans. Moisture, fat, ash, and carbohydrate contents of raw fish ranged between 48.01% and 83.05%, 0.87% and 30.48%, 1.10% and 1.61%, and 0.09% and 8.70%, respectively. All fresh fish investigated were high in protein: 11.20-17.14 g/100 g. Wide variations in protein content (18.11-25.65 g/100 g) between species and methods of cooking were observed. Fried fish had intermediate fat values, whereas grilled and steamed fishes had a comparatively low value.

  6. Origin of particulate organic carbon in the marine atmosphere as indicated by it stable carbon isotopic composition

    International Nuclear Information System (INIS)

    Chesselet, R.; Fontugne, M.; Buat-Menard, P.; Ezat, U.; Lambert, C.E.

    1981-01-01

    Organic carbon concentration and isotopic composition were determined in samples of atmospheric particulate matter collected in 1979 at remote marine locations (Enewetak atoll, Sargasso Sea) during the SEAREX (Sea-Air Exchange) program field experiments. Atmospheric Particulate Organic Carbon (POC) concentrations were found to be in the range of 0.3 to 1.2 mg. m -3 , in agreement with previous literature data. The major mass of POC was found on the smallest particles (r 13 C/ 12 C of the small particles is close to the one expected (d 13 C = 26 +- 2 0 //sub infinity/) for atmospheric POC of continental origin. For all the samples analysed so far, it appears that more than 80% of atmospheric POC over remote marine areas is of continental origin. This can be explained either by long-range transport of small sized continental organic aserosols or by the production of POC in the marine atmosphere from a vapor phase organic carbon pool of continental origin. The POC in the large size fraction of marine aerosols ( 13 C = -21 +- 2 0 / 00 ) for POC associated with sea-salt droplets transported to the marine atmosphere

  7. Organic molecular composition of marine aerosols over the Arctic Ocean in summer: contributions of primary emission and secondary aerosol formation

    OpenAIRE

    P. Q. Fu; K. Kawamura; J. Chen; B. Charrière; R. Sempéré

    2013-01-01

    Organic molecular composition of marine aerosol samples collected during the MALINA cruise in the Arctic Ocean was investigated by gas chromatography/mass spectrometry. More than 110 individual organic compounds were determined in the samples and were grouped into different compound classes based on the functionality and sources. The concentrations of total quantified organics ranged from 7.3 to 185 ng m−3 (mean 47.6 ng m−3), accounting ...

  8. Heat transfer in heterogeneous propellant combustion systems

    International Nuclear Information System (INIS)

    Brewster, M.Q.

    1992-01-01

    This paper reports that heat transfer plays an important role in several critical areas of heterogeneous, solid-propellant combustion systems. These areas include heat feedback to the propellant surface, heat transfer between burning aluminum droplets and their surroundings, heat transfer to internal insulation systems, and heat transfer to aft-end equipment. Gas conduction dominates heat feedback to the propellant surface in conventional ammonium perchlorate (AP) composite propellants, although particle radiative feedback also plays a significant role in combustion of metalized propellants. Particle radiation plays a dominant role in heat transfer to internal insulation, compared with that of convection. However, conduction by impingement of burning aluminum particles, which has not been extensively studied, may also be significant. Radiative heat loss plays an important role in determining the burning rate of molten aluminum particles due to a highly luminous, oxide particle-laden, detached flame envelope. Radiation by aluminum oxide smoke particles also plays a dominant role in heat transfer from the exhaust plume to aft-end equipment. Uncertainties in aluminum oxide particle-size distribution and optical properties still make it difficult to predict radiative plume heat transfer accurately from first principles

  9. The composition of nucleation and Aitken modes particles during coastal nucleation events: evidence for marine secondary organic contribution

    Directory of Open Access Journals (Sweden)

    P. Vaattovaara

    2006-01-01

    Full Text Available Newly-formed nanometer-sized particles have been observed at coastal and marine environments world wide. Organic species have so far not been detected in those newly-formed nucleation mode particles. In this study, we applied the ultrafine organic tandem differential mobility analyzer method to study the possible existence of an organic fraction in recently formed coastal nucleation mode particles (d<20 nm at the Mace Head research station. Furthermore, effects of those nucleation events on potential cloud condensation nuclei were studied. The coastal events were typical for the Mace Head region and they occurred at low tide conditions during efficient solar radiation and enhanced biological activity in spring 2002. Additionally, a pulse height analyzer ultrafine condensation particle counter technique was used to study the composition of newly-formed particles formed in low tide conditions during a lower biological activity in October 2002. The overall results of the ultrafine organic tandem differential mobility analyzer and the pulse height analyzer ultrafine condensation particle counter measurements indicate that those coastally/marinely formed nucleation mode particles include a remarkable fraction of secondary organic products, beside iodine oxides, which are likely to be responsible for the nucleation. During clean marine air mass conditions, the origin of those secondary organic oxidation compounds can be related to marine coast and open ocean biota and thus a major fraction of the organics may originate from biosynthetic production of alkenes such as isoprene and their oxidation driven by iodine radicals, hydroxyl radicals, acid catalysis, and ozone during efficient solar radiation. During modified marine conditions, also anthropogenic secondary organic compounds may contribute to the nucleation mode organic mass, in addition to biogenic secondary organic compounds. Thus, the ultrafine organic tandem differential mobility analyzer

  10. Chemical composition and surfactant characteristics of marine foams investigated by means of UV-vis, FTIR and FTNIR spectroscopy.

    Science.gov (United States)

    Mecozzi, Mauro; Pietroletti, Marco

    2016-11-01

    In this study, we collected the ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) and Fourier transform near-infrared (FTNIR) spectra of marine foams from different sites and foams produced by marine living organisms (i.e. algae and molluscs) to retrieve information about their molecular and structural composition. UV-vis spectra gave information concerning the lipid and pigment contents of foams. FTIR spectroscopy gave a more detailed qualitative information regarding carbohydrates, lipids and proteins in addition with information about the mineral contents of foams. FTNIR spectra confirmed the presence of carbohydrates, lipids and proteins in foams. Then, due to the higher content of structural information of FTIR spectroscopy with respect to FTNIR and UV-vis, we join the FTIR spectra of marine foams to those of humic substance from marine sediments and to the spectra of foams obtained by living organisms. We submitted this resulting FTIR spectral dataset to statistical multivariate methods to investigate specific aspects of foams such as structural similarity among foams and in addition, contributions from the organic matter of living organisms. Cluster analysis (CA) evidenced several cases (i.e. clusters) of marine foams having high structural similarity with foams from vegetal and animal samples and with humic substance extracted from sediments. These results suggested that all the living organisms of the marine environment can give contributions to the chemical composition of foams. Moreover, as CA also evidenced cases of structural differences within foam samples, we applied two-dimensional correlation analysis (2DCORR) to the FTIR spectra of marine foams to investigate the molecular characteristics which caused these structural differences. Asynchronous spectra of two-dimensional correlation analysis showed that the structural heterogeneity among foam samples depended reasonably on the presence and on the qualitative difference of

  11. Propellers in Saturn's rings

    Science.gov (United States)

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

    2013-12-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We show evidence that B ring seems to harbor two distinct populations of propellers: "big" propellers covering tens of degrees in azimuth situated in the densest part of B ring, and "small" propellers in less dense inner B ring that are similar in size and shape to known A ring propellers. The population of "big" propellers is exemplified with a single object which is observed for 5 years of Cassini data. The object is seen as a very elongated bright stripe (40 degrees wide) in unlit Cassini images, and dark stripe in lit geometries. In total we report observing the feature in images at 18 different epochs between 2005 and 2010. In UVIS occultations we observe this feature as an optical depth depletion in 14 out of 93 occultation cuts at corrotating longitudes compatible with imaging data. Combining the available Cassini data we infer that the object is a partial gap located at r=112,921km embedded in the high optical depth region of the B ring. The gap moves at Kepler speed appropriate for its radial location. Radial offsets of the gap locations in UVIS occultations are consistent with an asymmetric propeller shape. The asymmetry of the observed shape is most likely a consequence of the strong surface mass density gradient, as the feature is located at an edge between

  12. Composition and predicted functional ecology of mussel - associated bacteria in Indonesian marine lakes

    NARCIS (Netherlands)

    Cleary, D.F.R.; Becking, L.E.; Polonia, A.; Freitas, R.M.; Gomes, N.

    2015-01-01

    In the present study, we sampled bacterial communities associated with mussels inhabiting two distinct coastal marine ecosystems in Kalimantan, Indonesia, namely, marine lakes and coastal mangroves. We used 16S rRNA gene pyrosequencing and predicted metagenomic analysis to compare microbial

  13. Technology of foamed propellants

    Energy Technology Data Exchange (ETDEWEB)

    Boehnlein-Mauss, Jutta; Kroeber, Hartmut [Fraunhofer Institut fuer Chemische Technologie ICT, Pfinztal (Germany)

    2009-06-15

    Foamed propellants are based on crystalline explosives bonded in energetic reaction polymers. Due to their porous structures they are distinguished by high burning rates. Energy content and material characteristics can be varied by using different energetic fillers, energetic polymers and porous structures. Foamed charges can be produced easily by the reaction injection moulding process. For the manufacturing of foamed propellants a semi-continuous remote controlled production plant in pilot scale was set up and a modified reaction injection moulding process was applied. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  14. Seasonal variation in the composition and concentration of butyltin compounds in marine fish of Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Dong, C.D.; Chen, C.W.; Liu, L.L

    2004-10-01

    For the first time, strong evidence is presented to demonstrate that the accumulations of butyltin compounds (BTs) exhibit seasonal variations with respect to their compositions and concentrations in marine fishes. Measurements were made on the benthic ponyfish Leiogenathus splendens and lizardfish Trachinocephalus myops inhabiting the west coast of Taiwan. In the whole body samples of the ponyfish, BT concentrations ranged from 236 to 2501 ng/g wet wt, with those in winter considerably higher than in the other seasons (p<0.05). In a similar vein, proportions of mono- (MBT), di- (DBT) and tributyltin (TBT) differed significantly (p<0.001) depending upon the season, with TBT (75 and 50%) dominant in winter and spring and DBT (37 and 57%) and MBT (42 and 24%) dominant in summer and autumn, respectively. In the lizardfish, the concentrations of BTs were one to two orders of magnitude higher in the liver than in the muscle, i.e. 3058-11,473 vs. 36-159 ng/g wet wt, respectively. Concentrations of MBT, DBT and TBT in the muscle ranged, respectively, from 5 to 14, 8 to 35 and 23 to 110 ng/g wet wt, with the major compound being TBT (57-69%) in all seasons. However, in the liver, DBT concentrations, ranging from 992 to 7797 ng/g wet wt, differed seasonally with a descending order of autumn > summer > spring (p<0.05). Meanwhile, TBT (41%) was predominant in spring, whereas DBT (50 and 68%) was most heavily concentrated in summer and autumn (p<0.001). Seasonally mediated physiological changes, such as dilution due to growth and metabolic compensation, may play important roles in forming different BT accumulation patterns among seasons and organisms.

  15. Exposure to Crude Oil and Chemical Dispersant May Impact Marine Microbial Biofilm Composition and Steel Corrosion

    Directory of Open Access Journals (Sweden)

    Jennifer L. Salerno

    2018-06-01

    Full Text Available The release of hydrocarbons and chemical dispersant in marine environments may disrupt benthic ecosystems, including artificial reefs, formed by historic steel shipwrecks, and their associated organisms. Experiments were performed to determine the impacts of crude oil, dispersed crude oil, and dispersant on the community structure and function of microorganisms in seawater (SW and biofilms formed on carbon steel, a common ship hull construction material. Steel corrosion was also monitored to illustrate how oil spills may impact preservation of steel shipwrecks. Microcosms were filled with seawater (SW and incubated at 4°C. Carbon steel disks (CSDs were placed in each tank, and tanks were amended with crude oil and/or dispersant or no treatment. SW and CSD biofilms were sampled biweekly for genetic analysis using Illumina sequencing of 16S ribosomal RNA gene amplicons. Predicted and sequenced bacterial metagenomes were analyzed to examine impacts of oil and dispersant on metabolic function. Gammaproteobacteria, Alphaproteobacteria, and Flavobacteriia dominated SW and biofilms. Bacterial community structure differed significantly between treatments for SW and biofilms. OTUs affiliated with known (Pseudomonas and potential (Marinomonas hydrocarbon-degraders were roughly twice as abundant in biofilms treated with oil and dispersed oil, and steel corrosion of CSDs in these treatments was higher compared to control and dispersant treatments. OTUs affiliated with the Rhodobacteraceae family (biofilm formers and potential oil degraders were less abundant in the dispersant treatment compared to other treatments in biofilm and SW samples, but OTUs affiliated with the Pseudoalteromonas genus (biofilm formers and proposed hydrocarbon degraders were more abundant in dispersant-treated biofilms. Overall, functional gene analyses revealed a decrease in genes (predicted using PICRUSt and observed in sequenced metagenomes associated with hydrocarbon degradation

  16. 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.

  17. Propeller TAP flap

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  18. New Propellants and Cryofuels

    Science.gov (United States)

    Palasezski, Bryan; Sullivan, Neil S.; Hamida, Jaha; Kokshenev, V.

    2006-01-01

    The proposed research will investigate the stability and cryogenic properties of solid propellants that are critical to NASA s goal of realizing practical propellant designs for future spacecraft. We will determine the stability and thermal properties of a solid hydrogen-liquid helium stabilizer in a laboratory environment in order to design a practical propellant. In particular, we will explore methods of embedding atomic species and metallic nano-particulates in hydrogen matrices suspended in liquid helium. We will also measure the characteristic lifetimes and diffusion of atomic species in these candidate cryofuels. The most promising large-scale advance in rocket propulsion is the use of atomic propellants; most notably atomic hydrogen stabilized in cryogenic environments, and metallized-gelled liquid hydrogen (MGH) or densified gelled hydrogen (DGH). The new propellants offer very significant improvements over classic liquid oxygen/hydrogen fuels because of two factors: (1) the high energy-release, and (ii) the density increase per unit energy release. These two changes can lead to significant reduced mission costs and increased payload to orbit weight ratios. An achievable 5 to 10 percent improvement in specific impulse for the atomic propellants or MGH fuels can result in a doubling or tripling of system payloads. The high-energy atomic propellants must be stored in a stabilizing medium such as solid hydrogen to inhibit or delay their recombination into molecules. The goal of the proposed research is to determine the stability and thermal properties of the solid hydrogen-liquid helium stabilizer. Magnetic resonance techniques will be used to measure the thermal lifetimes and the diffusive motions of atomic species stored in solid hydrogen grains. The properties of metallic nano-particulates embedded in hydrogen matrices will also be studied and analyzed. Dynamic polarization techniques will be developed to enhance signal/noise ratios in order to be able to

  19. Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

    Science.gov (United States)

    Kim, Sang-Young; Shim, Chun Sik; Sturtevant, Caleb; Kim, Dave (Dae-Wook); Song, Ha Cheol

    2014-09-01

    Glass Fiber Reinforced Plastic (GFRP) structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties

  20. Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

    Directory of Open Access Journals (Sweden)

    Kim Sang-Young

    2014-09-01

    Full Text Available Glass Fiber Reinforced Plastic (GFRP structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties

  1. Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

    Directory of Open Access Journals (Sweden)

    Sang-Young Kim

    2014-09-01

    Full Text Available Glass Fiber Reinforced Plastic (GFRP structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties.

  2. Composition and potential origin of marine debris stranded in the Western Indian Ocean on remote Alphonse Island, Seychelles

    International Nuclear Information System (INIS)

    Duhec, Aurélie V.; Jeanne, Richard F.; Maximenko, Nikolai; Hafner, Jan

    2015-01-01

    The abundance, composition, and potential sources of marine debris were investigated on remote Alphonse Island, during the austral winter 2013. A total of 4743 items, weighing 142 kg, were removed from 1 km of windward beach, facing the prevailing southeasterly trade winds. Our study demonstrates the prevalence of plastic debris as a world-wide marine contaminant. Characteristics of the debris suggest it originated primarily from land-based sources. To determine their potential geographic sources we used the Surface Current from Diagnostic model of near-surface ocean currents, forced by satellite sea level and wind data. While preliminary evidence indicated the Southeast Asia to be the main source of the flotsam, the model highlighted Somalia as another potential primary source. Our study concludes that most of the collected debris entered the sea as a result of inadequate waste management and demonstrates how anthropogenic waste can negatively impact even the most remote environments

  3. Variations in stomach contents and biochemical composition of tissues in some marine fishes

    Digital Repository Service at National Institute of Oceanography (India)

    Jacob, P.G.; Rajagopal, M.D.

    Relationship between calorific values and protein, fat and carbohydrate of the stomach contents (food) and body tissues of marine fishes, Sardinella longiceps, Valenciennes, Rastrelliger kanagurta (Cuvier), Otolithus ruber (Schneider) and Lactarius...

  4. Biogeographic Characterization of Benthic Composition within the Flower Garden Banks National Marine Sanctuary (2006 - 2007)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The overarching goal of this collaboration was to provide the Flower Garden Banks National Marine Sanctuary (FGBNMS) staff with information on biogeographic patterns...

  5. Composite cement mortars based on marine sediments and oyster shell powder

    Directory of Open Access Journals (Sweden)

    Ez-zaki, H.

    2016-03-01

    Full Text Available Additions of dredged marine sediments and oyster shell powder (OS as cement substitute materials in mortars are examined by several techniques. The sediments have high water and chloride contents and calcite, quartz, illite and kaolinite as principal minerals. The OS powders are entirely composed of calcium carbonate and traces of other impurities. Four mixtures of treated sediments and OS powders at 650 °C and 850 °C are added to Portland cement at 8%, 16% and 33% by weight. The hydration of composite pastes is followed by calorimetric tests, the porosity accessible to water, the bulk density, the permeability to gas, the compressive strength and the accelerated carbonation resistance are measured. In general, the increase of addition amounts reduced the performance of mortars. However, a reduction of gas permeability was observed when the addition was up to 33%. Around 16% of addition, the compressive strength and carbonation resistance were improved.En este trabajo se ha valorado la sustitución de cemento en morteros por sedimentos marinos dragados y polvo de concha de ostra (OS. Los sedimentos tienen altos contenidos de agua, cloruros, calcita, cuarzo, illita y caolinita como minerales principales. Los polvos OS están compuestos de carbonato cálcico y trazas de otras impurezas. Se añadieron a un cemento Portland, cuatro mezclas de los sedimentos y polvos de OS tratados a 650 °C y 850 °C en proporciones del 8%, 16% y 33% en peso. La hidratación de pastas se estudió a través de calorimetría. Se estudió además la porosidad accesible al agua, densidad aparente, permeabilidad al gas, resistencia a compresión y carbonatación acelerada. En general, un aumento en la adición produjo una reducción del rendimiento de los morteros. Se observó, sin embargo, una reducción de la permeabilidad a los gases con porcentajes de adición de hasta el 33%. Con valores del 16% de sustitución, mejoraron las resistencias mecánicas y la

  6. Population variance in prey, diets and their macronutrient composition in an endangered marine predator, the Franciscana dolphin

    Science.gov (United States)

    Denuncio, Pablo; Paso Viola, Maria N.; Machovsky-Capuska, Gabriel E.; Raubenheimer, David; Blasina, Gabriela; Machado, Rodrigo; Polizzi, Paula; Gerpe, Marcela; Cappozzo, Humberto L.; Rodriguez, Diego H.

    2017-11-01

    Disentangling the intricacies governing dietary breadth in wild predators is important for understanding their role in structuring ecological communities and provides critical information for the management and conservation of ecologically threatened species. Here we combined dietary analysis, nutritional composition analysis of prey, literature data and nutritional geometry (right-angled mixture triangle models -RMT-) to examine the diet of the most threatened small cetacean in the western South Atlantic Ocean, the Franciscana dolphin (Pontoporia blainvillei). We applied a recently developed extension of niche theory based on the RMT to help understand the dietary strategies of this species. Our results showed that across their range the Franciscanas consumed prey with variable protein-to-lipid energy ratios (LMM, p < 0.001). In an intensive study of one area, FMA IV, we found that dolphins sub-populations, which recent genetic evidence suggest should be differentiated into three management units, have diets with different protein energy and water mass compositions, but similar protein-to-lipid energy ratios. Furthermore, dolphins from the three areas mixed different combinations of prey in their diets to achieve the observed macronutrient ratios. These results suggest that the different habitats that each sub-population occupies (estuarine, north marine area and south marine) might be associated with different prey composition niches, but similar realized nutritional niches. Future priorities are to better comprehend possible geographical and long-term seasonal effects on prey consumption and dietary breadth of the different Franciscana populations to identify potential impacts (environmental and human-related), enhance the current management strategies to protect this endangered marine predator.

  7. Chemical and isotopic composition of marine organic matter as indicators of its origin

    International Nuclear Information System (INIS)

    Malej, A.

    1989-07-01

    The present study was carried out to evaluate the relative importance of marine and terrestrial sources of Particulate Organic Matter (POM) in the Northern Adriatic Sea. Samples of POM were obtained from the water column at 14 stations using Niskin bottles at 4 depths and sediment traps (placed near the sea floor). Additional samples were obtained of likely source organic matter: sewage, river POM, phytoplankton bloom material, zooplankton, jelly-fish and bethic macrophytes. All samples were analyzed for total carbon and nitrogen and the delta C-13/C-12 ratio (by mass spectrometry). Marine and terrestrial sources of POM were clearly distinguished by their isotopic ratios. A linear model was set up to evaluate the relative importance of these sources at each sampling station. Except in the immediate vicinity of river sources, the marine component appears to dominate. 7 refs, 5 figs, 1 tab

  8. Marine Microbial Gene Abundance and Community Composition in Response to Ocean Acidification and Elevated Temperature in Two Contrasting Coastal Marine Sediments

    Directory of Open Access Journals (Sweden)

    Ashleigh R. Currie

    2017-08-01

    Full Text Available Marine ecosystems are exposed to a range of human-induced climate stressors, in particular changing carbonate chemistry and elevated sea surface temperatures as a consequence of climate change. More research effort is needed to reduce uncertainties about the effects of global-scale warming and acidification for benthic microbial communities, which drive sedimentary biogeochemical cycles. In this research, mesocosm experiments were set up using muddy and sandy coastal sediments to investigate the independent and interactive effects of elevated carbon dioxide concentrations (750 ppm CO2 and elevated temperature (ambient +4°C on the abundance of taxonomic and functional microbial genes. Specific quantitative PCR primers were used to target archaeal, bacterial, and cyanobacterial/chloroplast 16S rRNA in both sediment types. Nitrogen cycling genes archaeal and bacterial ammonia monooxygenase (amoA and bacterial nitrite reductase (nirS were specifically targeted to identify changes in microbial gene abundance and potential impacts on nitrogen cycling. In muddy sediment, microbial gene abundance, including amoA and nirS genes, increased under elevated temperature and reduced under elevated CO2 after 28 days, accompanied by shifts in community composition. In contrast, the combined stressor treatment showed a non-additive effect with lower microbial gene abundance throughout the experiment. The response of microbial communities in the sandy sediment was less pronounced, with the most noticeable response seen in the archaeal gene abundances in response to environmental stressors over time. 16S rRNA genes (amoA and nirS were lower in abundance in the combined stressor treatments in sandy sediments. Our results indicated that marine benthic microorganisms, especially in muddy sediments, are susceptible to changes in ocean carbonate chemistry and seawater temperature, which ultimately may have an impact upon key benthic biogeochemical cycles.

  9. Organic molecular composition of marine aerosols over the Arctic Ocean in summer: contributions of primary emission and secondary aerosol formation

    Directory of Open Access Journals (Sweden)

    P. Q. Fu

    2013-02-01

    Full Text Available Organic molecular composition of marine aerosol samples collected during the MALINA cruise in the Arctic Ocean was investigated by gas chromatography/mass spectrometry. More than 110 individual organic compounds were determined in the samples and were grouped into different compound classes based on the functionality and sources. The concentrations of total quantified organics ranged from 7.3 to 185 ng m−3 (mean 47.6 ng m−3, accounting for 1.8–11.0% (4.8% of organic carbon in the marine aerosols. Primary saccharides were found to be dominant organic compound class, followed by secondary organic aerosol (SOA tracers formed from the oxidation of biogenic volatile organic compounds (VOCs such as isoprene, α-pinene and β-caryophyllene. Mannitol, the specific tracer for airborne fungal spores, was detected as the most abundant organic species in the samples with a concentration range of 0.052–53.3 ng m−3 (9.2 ng m−3, followed by glucose, arabitol, and the isoprene oxidation products of 2-methyltetrols. Biomass burning tracers such as levoglucosan are evident in all samples with trace levels. On the basis of the tracer-based method for the estimation of fungal-spore OC and biogenic secondary organic carbon (SOC, we estimate that an average of 10.7% (up to 26.2% of the OC in the marine aerosols was due to the contribution of fungal spores, followed by the contribution of isoprene SOC (mean 3.8% and α-pinene SOC (2.9%. In contrast, only 0.19% of the OC was due to the photooxidation of β-caryophyllene. This study indicates that primary organic aerosols from biogenic emissions, both from long-range transport of mid-latitude aerosols and from sea-to-air emission of marine organics, as well as secondary organic aerosols formed from the photooxidation of biogenic VOCs are important factors controlling the organic chemical composition of marine aerosols in the Arctic Ocean.

  10. Nitrogen and carbon isotopic composition of bone collagen from marine and terrestrial animals

    International Nuclear Information System (INIS)

    Schoeninger, M.J.; DeNiro, M.J.

    1984-01-01

    The stable nitrogen and carbon isotope ratios of bone collagen prepared from more than 100 animals representing 66 species of birds, fish, and mammals are presented. The delta 15 N values of bone collagen from animals that fed exclusively in the marine environment are, on average, 9 per mille more positive than those from animals that fed exclusively in the terrestrial environment: ranges for the two groups overlap by less than 1 per mille. Bone collagen delta 15 N values also serve to separate marine fish from the small number of freshwater fish we analyzed. The bone collagen delta 15 N values of birds and fish that spent part of their life cycles feeding in the marine environment and part in the freshwater environment are intermediate between those of animals that fed exclusively in one or the other system. Further, animals that fed at successive trophic levels in the marine and terrestrial environment are separated, on average, by a 3 per mille difference in the delta 15 N values of their bone collagen. Results are given and discussed. (author)

  11. Chemical composition of marine macrophytes and their surrounding water and sediments, from Minicoy, Lakshadweep

    Digital Repository Service at National Institute of Oceanography (India)

    Jagtap, T.G.; Untawale, A.G.

    Among the marine algae studied, Herposiphonia spp showed highest concentration of nitrogen (6.55%). In seagrasses, Cymodocea rotundata was rich in nitrogen (6.19%) and organic carbon (30.8%). In general seagrasses were rich in the major elements...

  12. Small transport aircraft technology propeller study

    Science.gov (United States)

    Black, B. M.; Magliozzi, B.; Rohrbach, C.

    1983-01-01

    A study to define potential benefits of advanced technology propeller for 1985-1990 STAT commuter airplanes was completed. Two baselines, a Convair, 30 passenger, 0.47 Mach number airplane and a Lockheed, 50 passenger, 0.70 Mach number airplane, were selected from NASA-Ames sponsored airframe contracts. Parametric performance, noise level, weight and cost trends for propellers with varying number of blades, activity factor, camber and diameter incorporating blade sweep, tip proplets, advanced composite materials, advanced airfoils, advanced prevision synchrophasing and counter-rotation are presented. The resulting DOC, fuel burned, empty weight and acquisition cost benefits are presented for resizings of the two baseline airplanes. Six-bladed propeller having advanced composite blades, advanced airfoils, tip proplets and advanced prevision synchrophasers provided the maximum DOC improvements for both airplanes. DOC and fuel burned were reduced by 8.3% and 17.0% respectively for the Convair airplane and by 24.9% and 41.2% respectively for the Lockheed airplane. The larger reductions arose from a baseline definition with very heavy fuselage acoustic treatment. An alternate baseline, with a cabin noise 13dB in excess of the objective, was also studied.

  13.  Marine derived dinoflagellates in Antarctic saline lakes: Community composition and annual dynamics

    DEFF Research Database (Denmark)

    Rengefors, K.; Layborn-Parry, L.; Logares, R.

    2008-01-01

    polar dinoflagellate community, and not freshwater species. Polarella glacialis Montresor, Procaccini et Stoecker, a bipolar marine species, was for the first time described in a lake habitat and was an important phototrophic component in the higher salinity lakes. In the brackish lakes, we found a new...... sibling species to the brackish-water species Scrippsiella hangoei (J. Schiller) J. Larsen, previously observed only in the Baltic Sea....

  14. Biochemical composition of the marine conditioning film: Implications for bacterial adhesion

    Digital Repository Service at National Institute of Oceanography (India)

    Jain, A.; Bhosle, N

    1980; Fletcher and Marshall 1982; Abbott et al. 1983; Frolund et al. 1996; Azeredo and Oliveira 2000; Gubner and Beech 2000). Carbohydrates account for *10 to 50% of dissolved organic carbon in marine waters (Pakulski and Benner 1994; Amon and Benner... in bacterial adhesion to surfaces. Conversely, bacterial adhesion to a protein-rich conditioning film was inhibited (Fletcher 1980; Fletcher and Marshall 1982; Abbott et al. 1983; Husmark and Ronner 1993). It appears that the proteins of the conditioning film...

  15. Macromolecular composition of terrestrial and marine organic matter in sediments across the East Siberian Arctic Shelf

    Science.gov (United States)

    Sparkes, Robert B.; Doğrul Selver, Ayça; Gustafsson, Örjan; Semiletov, Igor P.; Haghipour, Negar; Wacker, Lukas; Eglinton, Timothy I.; Talbot, Helen M.; van Dongen, Bart E.

    2016-10-01

    Mobilisation of terrestrial organic carbon (terrOC) from permafrost environments in eastern Siberia has the potential to deliver significant amounts of carbon to the Arctic Ocean, via both fluvial and coastal erosion. Eroded terrOC can be degraded during offshore transport or deposited across the wide East Siberian Arctic Shelf (ESAS). Most studies of terrOC on the ESAS have concentrated on solvent-extractable organic matter, but this represents only a small proportion of the total terrOC load. In this study we have used pyrolysis-gas chromatography-mass spectrometry (py-GCMS) to study all major groups of macromolecular components of the terrOC; this is the first time that this technique has been applied to the ESAS. This has shown that there is a strong offshore trend from terrestrial phenols, aromatics and cyclopentenones to marine pyridines. There is good agreement between proportion phenols measured using py-GCMS and independent quantification of lignin phenol concentrations (r2 = 0.67, p radiocarbon data for bulk OC (14COC) which, when coupled with previous measurements, allows us to produce the most comprehensive 14COC map of the ESAS to date. Combining the 14COC and py-GCMS data suggests that the aromatics group of compounds is likely sourced from old, aged terrOC, in contrast to the phenols group, which is likely sourced from modern woody material. We propose that an index of the relative proportions of phenols and pyridines can be used as a novel terrestrial vs. marine proxy measurement for macromolecular organic matter. Principal component analysis found that various terrestrial vs. marine proxies show different patterns across the ESAS, and it shows that multiple river-ocean transects of surface sediments transition from river-dominated to coastal-erosion-dominated to marine-dominated signatures.

  16. Effect of marine by-product meals on hen egg production parameters, yolk lipid composition and sensory quality.

    Science.gov (United States)

    Toyes-Vargas, E; Ortega-Pérez, R; Espinoza-Villavicencio, J L; Arellano-Pérez, M; Civera, R; Palacios, E

    2018-04-01

    The effect of including 5% marine by-product meals in feeds of laying hens on egg production, composition and sensory characteristics was tested. Marine by-product meals were prepared using two methods: (i) cooking (100°C/10 min) followed by drying (60°C/24 hr) or (ii) grinding followed by drying. The raw materials used for meal production were scallop or squid viscera, shrimp heads or whole mackerel. A total of 108 laying hens were allocated to nine diet treatments; one control diet (corn and soya bean based) and eight experimental diets, containing 95% of the control feed and 5% of the experimental meal for three weeks. Daily intake was higher in hens fed the dried mackerel and cooked shrimp meals. All the experimental treatments showed significantly higher concentration of n-3 HUFA in yolk reserves and phospholipids compared to the control (0.12-0.13 g per 100 g), especially those with scallop or squid prepared by both methods (0.53-0.95 g per 100 g). Scallop, squid and shrimp meal inclusion in the feed produced eggs with more astaxanthin (0.22 mg per 100 g) while this carotenoid was absent in the control and mackerel treatments. Visual evaluation of raw yolk colour increased with the inclusion of marine by-product meals with higher values in hens fed shrimp heads (13), followed by scallop viscera (11), squid viscera (9), and with similar values for mackerel and control (4). The taste, aroma, texture and colour of cooked eggs from different treatments were not statically different when evaluated by a panel of 60 untrained people. These results suggest that meals from marine by-products are a better alternative for improving egg yolk composition by increasing n-3 HUFA when compared to fishmeal as they also increase astaxanthin and yolk pigmentation without affecting egg sensory characteristics. © 2017 Blackwell Verlag GmbH.

  17. Strength of Screw Propellers

    Science.gov (United States)

    1975-07-07

    ship because of increese of propeller efficiency and saving on the high cost of difficult to obtain materials (bronze, brass, stainless steel). The...indAjate that. x :axmuin stresses in the blade cross section are the cor-,prc-.,; ivFe norm-al strcs3es at point G. The maximom tensile stres-ses cis a...and stern part of the ship. Because of purely technical difficulties and also because of the relatively high cost of preparations for such tests, only

  18. Macromolecular composition of terrestrial and marine organic matter in sediments across the East Siberian Arctic Shelf

    Directory of Open Access Journals (Sweden)

    R. B. Sparkes

    2016-10-01

    Full Text Available Mobilisation of terrestrial organic carbon (terrOC from permafrost environments in eastern Siberia has the potential to deliver significant amounts of carbon to the Arctic Ocean, via both fluvial and coastal erosion. Eroded terrOC can be degraded during offshore transport or deposited across the wide East Siberian Arctic Shelf (ESAS. Most studies of terrOC on the ESAS have concentrated on solvent-extractable organic matter, but this represents only a small proportion of the total terrOC load. In this study we have used pyrolysis–gas chromatography–mass spectrometry (py-GCMS to study all major groups of macromolecular components of the terrOC; this is the first time that this technique has been applied to the ESAS. This has shown that there is a strong offshore trend from terrestrial phenols, aromatics and cyclopentenones to marine pyridines. There is good agreement between proportion phenols measured using py-GCMS and independent quantification of lignin phenol concentrations (r2 = 0.67, p < 0.01, n = 24. Furfurals, thought to represent carbohydrates, show no offshore trend and are likely found in both marine and terrestrial organic matter. We have also collected new radiocarbon data for bulk OC (14COC which, when coupled with previous measurements, allows us to produce the most comprehensive 14COC map of the ESAS to date. Combining the 14COC and py-GCMS data suggests that the aromatics group of compounds is likely sourced from old, aged terrOC, in contrast to the phenols group, which is likely sourced from modern woody material. We propose that an index of the relative proportions of phenols and pyridines can be used as a novel terrestrial vs. marine proxy measurement for macromolecular organic matter. Principal component analysis found that various terrestrial vs. marine proxies show different patterns across the ESAS, and it shows that multiple river–ocean transects of surface sediments transition from river-dominated to

  19. Graphite coated with manganese oxide/multiwall carbon nanotubes composites as anodes in marine benthic microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yubin, E-mail: ffyybb@ouc.edu.cn; Yu, Jian; Zhang, Yelong; Meng, Yao

    2014-10-30

    Highlights: • MnO{sub 2}/MWCNTs composites anode exhibits faster reaction kinetics. • The surfaces of MnO{sub 2}/MWCNTs composites anode exhibits better wettability. • A BMFC using the modified anode have excellent power output. - Abstract: Improving anode performance is of great significance to scale up benthic microbial fuel cells (BMFCs) for its marine application to drive oceanography instruments. In this study, manganese oxide (MnO{sub 2})/multiwall carbon nanotubes (MWCNTs) composites are prepared to be as novel anodes in the BMFCs via a direct redox reaction between permanganate ions (MnO{sub 4}{sup −}) and MWCNTs. The results indicate that the MnO{sub 2}/MWCNTs anode has a better wettability, greater kinetic activity and higher power density than that of the plain graphite (PG) anode. It is noted that the MnO{sub 2} (50% weight percent)/MWCNTs anode shows the highest electrochemical performance among them and will be a promising material for improving bioelectricity production of the BMFCs. Finally, a synergistic mechanism of electron transfer shuttle of Mn ions and their redox reactions in the interface between modified anode and bacteria biofilm are proposed to explain its excellent electrochemical performance.

  20. Preparation of ZnO/SnO2 Composite Nanometer Photocatalyst and Photocatalytic Treatment of Marine Diesel Pollution

    Science.gov (United States)

    Zhang, J.; Yu, X. C.; Nie, Z. W.; Guo, M. C.; Liu, J. H.; Wang, L. P.

    2017-12-01

    The ZnO/SnO2 composite nanophotocatalyst studied in this paper was prepared by a chemical precipitation method, which were characterized by XRD and SEM. The results show that the prepared samples were rutile SnO2 particles and the average grain size is 8.41 nm. In this paper, the factors for the degradation efficiency of marine diesel oil degraded by ZnO/SnO2 composite nanophotocatalyst are the catalysts’ doping ratio, the initial concentration of oil, the pH value of seawater, the dosage of catalyst and the dosage of hydrogen peroxide. The results show that the ZnO/SnO2 composite nanophotocatalyst can effectively degrade seawater diesel oil under UV light. When the doping ratio of ZnO and SnO2 is 0.35, the reaction time is 2.5 hours, the pH value of seawater with oil is 7, The concentration of diesel oil is 0.1g/L, the dosage of catalyst is 0.3g/L and the dosage of hydrogen peroxide is 0.1 g/L, the highest degradation rate is 91.54%.

  1. Comparison of lipid content and Fatty Acid composition in the edible meat of wild and cultured freshwater and marine fish and shrimps from china.

    Science.gov (United States)

    Li, Guipu; Sinclair, Andrew J; Li, Duo

    2011-03-09

    The lipid content and fatty acid composition in the edible meat of twenty-nine species of wild and cultured freshwater and marine fish and shrimps were investigated. Both the lipid content and fatty acid composition of the species were specified due to their unique food habits and trophic levels. Most of the marine fish demonstrated higher lipid content than the freshwater fish, whereas shrimps had the lowest lipid content. All the marine fish and shrimps had much higher total n-3 PUFA than n-6 PUFA, while most of the freshwater fish and shrimps demonstrated much lower total n-3 PUFA than n-6 PUFA. This may be the biggest difference in fatty acid composition between marine and freshwater species. The cultured freshwater fish demonstrated higher percentages of total PUFA, total n-3 PUFA, and EPA + DHA than the wild freshwater fish. Two freshwater fish, including bighead carp and silver carp, are comparable to the marine fish as sources of n-3 PUFA.

  2. Composition and potential origin of marine debris stranded in the Western Indian Ocean on remote Alphonse Island, Seychelles.

    Science.gov (United States)

    Duhec, Aurélie V; Jeanne, Richard F; Maximenko, Nikolai; Hafner, Jan

    2015-07-15

    The abundance, composition, and potential sources of marine debris were investigated on remote Alphonse Island, during the austral winter 2013. A total of 4743 items, weighing 142 kg, were removed from 1 km of windward beach, facing the prevailing southeasterly trade winds. Our study demonstrates the prevalence of plastic debris as a world-wide marine contaminant. Characteristics of the debris suggest it originated primarily from land-based sources. To determine their potential geographic sources we used the Surface Current from Diagnostic model of near-surface ocean currents, forced by satellite sea level and wind data. While preliminary evidence indicated the Southeast Asia to be the main source of the flotsam, the model highlighted Somalia as another potential primary source. Our study concludes that most of the collected debris entered the sea as a result of inadequate waste management and demonstrates how anthropogenic waste can negatively impact even the most remote environments. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Improved enrichment culture technique for methane-oxidizing bacteria from marine ecosystems: the effect of adhesion material and gas composition.

    Science.gov (United States)

    Vekeman, Bram; Dumolin, Charles; De Vos, Paul; Heylen, Kim

    2017-02-01

    Cultivation of microbial representatives of specific functional guilds from environmental samples depends largely on the suitability of the applied growth conditions. Especially the cultivation of marine methanotrophs has received little attention, resulting in only a limited number of ex situ cultures available. In this study we investigated the effect of adhesion material and headspace composition on the methane oxidation activity in methanotrophic enrichments obtained from marine sediment. Addition of sterilized natural sediment or alternatively the addition of acid-washed silicon dioxide significantly increased methane oxidation. This positive effect was attributed to bacterial adhesion on the particles via extracellular compounds, with a minimum amount of particles required for effect. As a result, the particles were immobilized, thus creating a stratified environment in which a limited diffusive gas gradients could build up and various microniches were formed. Such diffusive gas gradient might necessitate high headspace concentrations of CH 4 and CO 2 for sufficient concentrations to reach the methane-oxidizing bacteria in the enrichment culture technique. Therefore, high concentrations of methane and carbon dioxide, in addition to the addition of adhesion material, were tested and indeed further stimulated methane oxidation. Use of adhesion material in combination with high concentrations of methane and carbon dioxide might thus facilitate the cultivation and subsequent enrichment of environmentally important members of this functional guild. The exact mechanism of the observed positive effects on methane oxidation and the differential effect on methanotrophic diversity still needs to be explored.

  4. A database of marine phytoplankton abundance, biomass and species composition in Australian waters

    Science.gov (United States)

    Davies, Claire H.; Coughlan, Alex; Hallegraeff, Gustaaf; Ajani, Penelope; Armbrecht, Linda; Atkins, Natalia; Bonham, Prudence; Brett, Steve; Brinkman, Richard; Burford, Michele; Clementson, Lesley; Coad, Peter; Coman, Frank; Davies, Diana; Dela-Cruz, Jocelyn; Devlin, Michelle; Edgar, Steven; Eriksen, Ruth; Furnas, Miles; Hassler, Christel; Hill, David; Holmes, Michael; Ingleton, Tim; Jameson, Ian; Leterme, Sophie C.; Lønborg, Christian; McLaughlin, James; McEnnulty, Felicity; McKinnon, A. David; Miller, Margaret; Murray, Shauna; Nayar, Sasi; Patten, Renee; Pritchard, Tim; Proctor, Roger; Purcell-Meyerink, Diane; Raes, Eric; Rissik, David; Ruszczyk, Jason; Slotwinski, Anita; Swadling, Kerrie M.; Tattersall, Katherine; Thompson, Peter; Thomson, Paul; Tonks, Mark; Trull, Thomas W.; Uribe-Palomino, Julian; Waite, Anya M.; Yauwenas, Rouna; Zammit, Anthony; Richardson, Anthony J.

    2016-06-01

    There have been many individual phytoplankton datasets collected across Australia since the mid 1900s, but most are unavailable to the research community. We have searched archives, contacted researchers, and scanned the primary and grey literature to collate 3,621,847 records of marine phytoplankton species from Australian waters from 1844 to the present. Many of these are small datasets collected for local questions, but combined they provide over 170 years of data on phytoplankton communities in Australian waters. Units and taxonomy have been standardised, obviously erroneous data removed, and all metadata included. We have lodged this dataset with the Australian Ocean Data Network (http://portal.aodn.org.au/) allowing public access. The Australian Phytoplankton Database will be invaluable for global change studies, as it allows analysis of ecological indicators of climate change and eutrophication (e.g., changes in distribution; diatom:dinoflagellate ratios). In addition, the standardised conversion of abundance records to biomass provides modellers with quantifiable data to initialise and validate ecosystem models of lower marine trophic levels.

  5. The stable isotope composition of nitrogen and carbon and elemental contents in modern and fossil seabird guano from Northern Chile - Marine sources and diagenetic effects.

    Directory of Open Access Journals (Sweden)

    Friedrich Lucassen

    Full Text Available Seabird excrements (guano have been preserved in the arid climate of Northern Chile since at least the Pliocene. The deposits of marine organic material in coastal areas potentially open a window into the present and past composition of the coastal ocean and its food web. We use the stable isotope composition of nitrogen and carbon as well as element contents to compare the principal prey of the birds, the Peruvian anchovy, with the composition of modern guano. We also investigate the impact of diagenetic changes on the isotopic composition and elemental contents of the pure ornithogenic sediments, starting with modern stratified deposits and extending to fossil guano. Where possible, 14C systematics is used for age information. The nitrogen and carbon isotopic composition of the marine prey (Peruvian anchovy of the birds is complex as it shows strong systematic variations with latitude. The detailed study of a modern profile that represents a few years of guano deposition up to present reveals systematic changes in nitrogen and carbon isotopic composition towards heavier values that increase with age, i.e. depth. Only the uppermost, youngest layers of modern guano show compositional affinity to the prey of the birds. In the profile, the simultaneous loss of nitrogen and carbon occurs by degassing, and non-volatile elements like phosphorous and calcium are passively enriched in the residual guano. Fossil guano deposits are very low in nitrogen and low in carbon contents, and show very heavy nitrogen isotopic compositions. One result of the study is that the use of guano for tracing nitrogen and carbon isotopic and elemental composition in the marine food web of the birds is restricted to fresh material. Despite systematic changes during diagenesis, there is little promise to retrieve reliable values of marine nitrogen and carbon signatures from older guano. However, the changes in isotopic composition from primary marine nitrogen isotopic

  6. Aerosol concentrations and composition in the North Pacific marine boundary layer

    Science.gov (United States)

    Choi, Yongjoo; Rhee, Tae Siek; Collett, Jeffrey L.; Park, Taehyun; Park, Seung-Myung; Seo, Beom-Keun; Park, Gyutae; Park, Keyhong; Lee, Taehyoung

    2017-12-01

    Ship-borne measurements of inorganic and organic aerosols, including methanesulfonic acid (MSA), were conducted over the Northern Pacific using a High Resolution Time of Flight Aerosol Mass Spectrometer (AMS). This study, conducted aboard the Korean ice breaker R/V Araon, was part of the SHIP-borne Pole-to-Pole Observations (SHIPPO) project. Based on air mass source region, the cruise track could be divided into five sections. Overall, the South Asia and Northern Japan ship transects showed higher aerosol concentrations due to continental pollution and biomass burning sources, respectively. In all five regions, the average mass concentrations of sulfate and organic aerosols (OA) were much higher than concentrations of nitrate and ammonium. Positive matrix factorization (PMF) analysis distinguished two organic aerosol factors as hydrocarbon-like and oxidized OA (HOA and OOA). HOA peaked in South Asia under the influence of anthropogenic pollution source areas, such as China and Korea, and generally decreased with increasing latitude across the full study region. OOA concentrations peaked in Northern Japan near the Tsugaru Strait and appear to reflect fine particle contributions from biomass burning. The mean HOA concentration in the clean marine area (Aleutian Island to Siberia) was 0.06 μg/m3 and comprised approximately 8% of the OA mass fraction. The highest MSA concentrations peaked in the Aleutian Islands at nearly 15 μg/m3, suggesting influence from higher dimethyl sulfide (DMS) emissions resulting from biological nutrient uptake during summer. The MSA/sulfate ratio, an indicator of the relative fine particle contributions of DMS and anthropogenic sources, revealed a sharp gradient as the ship approached the clean marine areas where the dominance of DMS increased. The patterns in OOA, HOA, and MSA concentrations found in this study provide a better understanding of the characteristics of inorganic and organic aerosols in the Northern Pacific Ocean.

  7. Novel Sustainable Composites Based on Poly(hydroxybutyrate-co-hydroxyvalerate and Seagrass Beach-CAST Fibers: Performance and Degradability in Marine Environments

    Directory of Open Access Journals (Sweden)

    Maurizia Seggiani

    2018-05-01

    Full Text Available In order to produce sustainable, bio-based and highly biodegradable materials, composites based on poly(hydroxybutyrate-co-hydroxyvalerate (PHBV and fibers of Posidonia oceanica (PO, a dominant Mediterranean seagrass, were produced by simple melt mixing and characterized in terms of thermal stability, morphology and rheological/mechanical properties. In view of their potential application in marine environments, degradation of the developed composites was evaluated under simulated and real marine environmental conditions for 1 year. Using 10 wt % of acetyl tributyl citrate (ATBC as a plasticizer, smooth processing was achieved for up to 30 wt % of PO fibers, despite the reduction of the melt fluidity observed with increasing fiber loading. The tensile modulus slightly increased (from 2 to 2.4 GPa while the tensile strength and the elongation decreased (from 23.6 to 21.5 MPa and from 3.2 to 1.9%, respectively by increasing the PO fiber content from 0 to 30 wt %. Interestingly, the impact resistance of the composites increased with the increasing of the PO content: the Charpy’s impact energy increased from 3.6 (without fiber to 4.4 kJ/m2 for the composite with 30 wt %. The results of the aerobic biodegradation under simulated marine conditions showed that the presence of PO fibers favored the physical disintegration of the composite increasing the biodegradation rate of the polymeric matrix: after 216 days, the composite with 20 wt % PO fibers showed a biodegradability of about 30% compared to 20% of the composite without fibers. Under real marine conditions, the specimens containing PO fibers showed higher weight losses and deterioration of tensile properties compared to those without fibers. Presumably, biodegradation occurred after colonization of the specimen, and the specimens with 20 wt % PO fibers showed well-developed biofilm consisting of bacteria and fungi on the surface after only 3 months of incubation in marine sediments, unlike the

  8. Novel Sustainable Composites Based on Poly(hydroxybutyrate-co-hydroxyvalerate) and Seagrass Beach-CAST Fibers: Performance and Degradability in Marine Environments

    Science.gov (United States)

    Mallegni, Norma; Stefanelli, Eleonora; Rossi, Alessia

    2018-01-01

    In order to produce sustainable, bio-based and highly biodegradable materials, composites based on poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and fibers of Posidonia oceanica (PO), a dominant Mediterranean seagrass, were produced by simple melt mixing and characterized in terms of thermal stability, morphology and rheological/mechanical properties. In view of their potential application in marine environments, degradation of the developed composites was evaluated under simulated and real marine environmental conditions for 1 year. Using 10 wt % of acetyl tributyl citrate (ATBC) as a plasticizer, smooth processing was achieved for up to 30 wt % of PO fibers, despite the reduction of the melt fluidity observed with increasing fiber loading. The tensile modulus slightly increased (from 2 to 2.4 GPa) while the tensile strength and the elongation decreased (from 23.6 to 21.5 MPa and from 3.2 to 1.9%, respectively) by increasing the PO fiber content from 0 to 30 wt %. Interestingly, the impact resistance of the composites increased with the increasing of the PO content: the Charpy’s impact energy increased from 3.6 (without fiber) to 4.4 kJ/m2 for the composite with 30 wt %. The results of the aerobic biodegradation under simulated marine conditions showed that the presence of PO fibers favored the physical disintegration of the composite increasing the biodegradation rate of the polymeric matrix: after 216 days, the composite with 20 wt % PO fibers showed a biodegradability of about 30% compared to 20% of the composite without fibers. Under real marine conditions, the specimens containing PO fibers showed higher weight losses and deterioration of tensile properties compared to those without fibers. Presumably, biodegradation occurred after colonization of the specimen, and the specimens with 20 wt % PO fibers showed well-developed biofilm consisting of bacteria and fungi on the surface after only 3 months of incubation in marine sediments, unlike the no

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

    DEFF Research Database (Denmark)

    Regener, Pelle Bo

    In order to predict the required propulsion power for a ship reliably and accurately, it is not sufficient to only evaluate the resistance of the hull and the propeller performance in open water alone. Interaction effects between hull and propeller can even be a decisive factor in ship powering...... prediction and design optimization. The hull-propeller interaction coefficients of effective wake fraction, thrust deduction factor, and relative rotative efficiency are traditionally determined by model tests. Self-propulsion model tests consistently show an increase in effective wake fractions when using...... velocities. This offers an opportunity for additional insight into hull-propeller interaction and the propeller’s actual operating condition behind the ship, as the actual (effective) inflow is computed. Self-propulsion simulations at model and full scale were carried out for a bulk carrier, once...

  10. Energy expenditure, nutritional status, body composition and physical fitness of Royal Marines during a 6-month operational deployment in Afghanistan.

    Science.gov (United States)

    Fallowfield, Joanne L; Delves, Simon K; Hill, Neil E; Cobley, Rosalyn; Brown, Pieter; Lanham-New, Susan A; Frost, Gary; Brett, Stephen J; Murphy, Kevin G; Montain, Scott J; Nicholson, Christopher; Stacey, Michael; Ardley, Christian; Shaw, Anneliese; Bentley, Conor; Wilson, Duncan R; Allsopp, Adrian J

    2014-09-14

    Understanding the nutritional demands on serving military personnel is critical to inform training schedules and dietary provision. Troops deployed to Afghanistan face austere living and working environments. Observations from the military and those reported in the British and US media indicated possible physical degradation of personnel deployed to Afghanistan. Therefore, the present study aimed to investigate the changes in body composition and nutritional status of military personnel deployed to Afghanistan and how these were related to physical fitness. In a cohort of British Royal Marines (n 249) deployed to Afghanistan for 6 months, body size and body composition were estimated from body mass, height, girth and skinfold measurements. Energy intake (EI) was estimated from food diaries and energy expenditure measured using the doubly labelled water method in a representative subgroup. Strength and aerobic fitness were assessed. The mean body mass of volunteers decreased over the first half of the deployment ( - 4·6 (sd 3·7) %), predominately reflecting fat loss. Body mass partially recovered (mean +2·2 (sd 2·9) %) between the mid- and post-deployment periods (Penergy expenditure (mean 15 167 (sd 1883) kJ) measured in a subgroup of volunteers. However, despite the body mass loss, aerobic fitness and strength were well maintained. Nutritional provision for British military personnel in Afghanistan appeared sufficient to maintain physical capability and micronutrient status, but providing appropriate nutrition in harsh operational environments must remain a priority.

  11. Size distribution and ionic composition of marine summer aerosol at the continental Antarctic site Kohnen

    Science.gov (United States)

    Weller, Rolf; Legrand, Michel; Preunkert, Susanne

    2018-02-01

    We measured aerosol size distributions and conducted bulk and size-segregated aerosol sampling during two summer campaigns in January 2015 and January 2016 at the continental Antarctic station Kohnen (Dronning Maud Land). Physical and chemical aerosol properties differ conspicuously during the episodic impact of a distinctive low-pressure system in 2015 (LPS15) compared to the prevailing clear sky conditions. The approximately 3-day LPS15 located in the eastern Weddell Sea was associated with the following: marine boundary layer air mass intrusion; enhanced condensation particle concentrations (1400 ± 700 cm-3 compared to 250 ± 120 cm-3 under clear sky conditions; mean ± SD); the occurrence of a new particle formation event exhibiting a continuous growth of particle diameters (Dp) from 12 to 43 nm over 44 h (growth rate 0.6 nm h-1); peaking methane sulfonate (MS-), non-sea-salt sulfate (nss-SO42-), and Na+ concentrations (190 ng m-3 MS-, 137 ng m-3 nss-SO42-, and 53 ng m-3 Na+ compared to 24 ± 15, 107 ± 20, and 4.1 ± 2.2 ng m-3, respectively, during clear sky conditions); and finally an increased MS- / nss-SO42- mass ratio βMS of 0.4 up to 2.3 (0.21 ± 0.1 under clear sky conditions) comparable to typical values found at coastal Antarctic sites. Throughout the observation period a larger part of MS- could be found in super-micron aerosol compared to nss-SO42-, i.e., (10 ± 2) % by mass compared to (3.2 ± 2) %, respectively. On the whole, under clear sky conditions aged aerosol characterized by usually mono-modal size distributions around Dp = 60 nm was observed. Although our observations indicate that the sporadic impacts of coastal cyclones were associated with enhanced marine aerosol entry, aerosol deposition on-site during austral summer should be largely dominated by typical steady clear sky conditions.

  12. Composition, nutritional aspects and effect on serum parameters of marine algae Ulva rigida.

    Science.gov (United States)

    Taboada, Cristina; Millán, Rosendo; Míguez, Isabel

    2010-02-01

    Algae are commonly consumed in Asia and have also gained popularity in Europe. However, data on the bioavailability of their components are limited. The present study was designed to determine the composition of Ulva rigida and the effects of inclusion of 10% of the algae in a standard diet for 4 weeks on nutritive value and serum parameters in order to consider the usefulness of Ulva as a dietary supplement. Ulva rigida is rich in protein, carbohydrates, fibre, vitamins and minerals and has a low lipid content. Analysis of the amino acid composition revealed good-quality protein. The algae were well accepted by experimental animals and did not significantly change nutritional parameters but reduced LDL cholesterol. Ulva rigida is an excellent source of nutrients and could improve a balanced diet. Further studies are required to research the potential of the seaweed as a natural source of bioactive compounds.

  13. Predation rates, timing, and predator composition for Scoters (Melanitta spp.) in marine habitats

    Science.gov (United States)

    Anderson, Eric J.; Esler, Daniel N.; Sean, Boyd W.; Evenson, Joseph; Nysewander, David R.; Ward, David H.; Dickson, Rian D.; Uher-Koch, Brian D.; Vanstratt, C.S.; Hupp, Jerry

    2012-01-01

    Studies of declining populations of sea ducks have focused mainly on bottom-up processes with little emphasis on the role of predation. We identified 11 potential predators of White-winged Scoters (Melanitta fusca (L., 1758)) and Surf Scoters (Melanitta perspicillata (L., 1758)) in North American marine habitats. However, of 596 Scoters marked with VHF transmitters along the Pacific coast, mortalities were recovered in association with just two identifiable categories of predators: in southeast Alaska recoveries occurred mainly near mustelid feeding areas, while those in southern British Columbia and Washington occurred mainly near feeding areas of Bald Eagles (Haliaeetus leucocephalus (L., 1766)). Determining whether marked Scoters had been depredated versus scavenged was often not possible, but mortalities occurred more frequently during winter than during wing molt (13.1% versus 0.7% of both species combined, excluding Scoters that died within a postrelease adjustment period). In two sites heavily used by Scoters, diurnal observations revealed no predation attempts and low rates of predator disturbances that altered Scoter behavior (≤ 0.22/h). These and other results suggest that predation by Bald Eagles occurs mainly at sites and times where densities of Scoters are low, while most predation by mustelids probably occurs when Scoters are energetically compromised.

  14. Chemical composition of marine sediments in the Pacific Ocean from Sinaloa to Jalisco, Mexico

    International Nuclear Information System (INIS)

    Martinez, T.; Lartigue, J.; Ramos, A.; Navarrete, M.; Mulller, G.

    2014-01-01

    Marine sediments from Mexico's West coast in the Pacific Ocean from Sinaloa to Jalisco were analyzed by energy-dispersive X-ray fluorescence technique. Ten sediment samples were collected in May, 2010 between 55.5 and 1264 m water depth with a Reinneck type box nucleate sampler. Sediments were dried and fractioned by granulometry. Their physical and chemical properties were determined in laboratory by standard methods, pH, and conductivity. Concentration and distribution of K, Ca, Ti Mn, Fe, Cu, Zn, Ga, Pb, Br and Sr were analyzed. In order to determine the status of the elements, enrichment factors were calculated. Total, organic carbon and CaCO 3 were also determined. Scanning electron microscopy and X-ray diffraction show predominant groups of compounds. As quality-control method, Certified Reference Material was both processed and analyzed at even conditions. Enrichment factors for K, Ca, Ti, Mn Fe, Cu, Zn, Ga, Ni, and Sr show they are conservative elements having concentrations in the range of unpolluted sites giving a base data line for the sampling zone In spite of moderately enrichment factors -1 ) and enrichment factor show the influence of anthropogenic sources with values between lowest effect level and a third part of 250 μg g -1 value, which is considered to have severe effect levels for aquatic life. (author)

  15. Size-differentiated composition of inorganic atmospheric aerosols of both marine and polluted continental origin

    Science.gov (United States)

    Harrison, Roy M.; Pio, Casimiro A.

    Atmospheric aerosols were sampled with a high volume impactor/diffusion battery system and the collected fractions analysed for their major water-soluble inorganic constituents. Sulphate, nitrate and chloride showed bimodal distributions; sulphate and nitrate were mainly associated with NH 4+, having approximately log-normal distributions with modes at 1.0 μm. In unpolluted maritime air, chlorides appeared as salts of sodium and magnesium with average modes at c. 5 μm, whilst in polluted air masses significant concentrations of ammonium chloride sub-μm aerosols were detected. Sodium nitrate and sodium sulphate aerosols having average modes of c. 3.5 μm were observed in mixed maritime/polluted air masses. The dimensions of these particles indicate formation from absorption of H 2SO 4 and HNO 3 at the surface of marine NaCl particles. The concentration of H + was very low, but the possibility of its neutralization by atmospheric ammonia during sampling was ruled out by parallel air sampling using an 'ammonia denuder'.

  16. Diagnostics of Gun Barrel Propellants

    National Research Council Canada - National Science Library

    Lederman, S

    1983-01-01

    A preliminary investigation of the applicability of the spontaneous Raman diagnostic technique to the determination of the temperature of the propellant gases in the vicinity of the muzzle of a 2Omm...

  17. 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...

  18. 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,

  19. 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.

  20. Isotopic compositions of potassium and calcium in magnetic spherulesfrom marine sediments

    International Nuclear Information System (INIS)

    Shimarura, T.; Yanagita, S.; Yamakoshi, K.; Nogami, K.; Arai, O.; Tazawa, Y.; Kobayashi, K.

    1979-01-01

    Isotopic compositions of potassium and calcium in individual magnetic spherules were determined. No significant anomaly was observed for potassium within twice the statistical error (2sigma), although for calcium isotopes enrichment of 46 Ca, 44 Ca and 42 Ca were observed in one spherule. The relative excess of 46 Ca, 44 Ca and 42 Ca in the spherule agrees with the relative yield of spallogenic calcium isotopes observed in iron meteorites. This fact indicates that the enrichment in the calcium isotopes was caused by cosmic ray irradiation of the spherule in outer space. (Auth.)

  1. Optimization of direct solvent lipid extraction kinetics on marine trebouxiophycean alga by central composite design – Bioenergy perspective

    International Nuclear Information System (INIS)

    Mathimani, Thangavel; Uma, Lakshmanan; Prabaharan, Dharmar

    2017-01-01

    Highlights: • Direct solvent extraction is an appropriate pretreatment for marine C. vulgaris. • 2:1 chloroform/methanol, 1:5 DCW/solvent, 65 °C and 120 min time are optimal variables. • Favorable R"2, Prob > F, F value and desirability ratio for all models was observed. • Precision and compatibility of the optimized process suit well with Picochlorum sp. • Fuel properties of biodiesel comply ASTM, EN and ISO standards. - Abstract: This present work compares various pretreatment techniques, single/binary solvent system, biomass drying methods and biomass particle sizes to ascertain effective lipid extraction process for marine trebouxiophycean microalga Chlorella vulgaris BDUG 91771. Of the tested methods, homogenization or direct solvent extraction (DSE) pretreatment, chloroform/methanol binary solvent system, and ≤600 µm particle size extracted maximum lipid of 22.1% irrespective of different biomass drying methods. Further, considering low energy consumption and industrial feasibility, optimization of DSE process kinetics was performed by central composite design. According to central composite design, high lipid recovery was attained with 2:1 chloroform/methanol ratio, 1:5 dry cell weight/solvent ratio, 65 °C temperature, 120 min reaction time, and it was highly validated by regression analysis, coefficient determination, F-value, coefficient variation, desirability ratio of the models. It is noteworthy that, the optimized DSE process was compatible with another trebouxiophycean alga Picochlorum sp. BDUG 91281 through biological and technical replicates. In a bioenergy outlook, fuel properties of C. vulgaris BDUG 91771 biodiesel such as degree of unsaturation (69.03), long chain saturation factor (2.49), cold filter plugging point (−9.75 °C), cloud point (8.1 °C), pour point (0.66 °C), saponification value (248.2 mg KOH/g), acid value (0.51 mg KOH/g), ash content (0.019%), insoluble impurities (0.022 g/kg) and viscosity (4.1 cSt) comply ASTM

  2. Dissolved organic matter composition drives the marine production of brominated very short-lived substances.

    Science.gov (United States)

    Liu, Yina; Thornton, Daniel C O; Bianchi, Thomas S; Arnold, William A; Shields, Michael R; Chen, Jie; Yvon-Lewis, Shari A

    2015-03-17

    Brominated very short-lived substances (BrVSLS), such as bromoform, are important trace gases for stratospheric ozone chemistry. These naturally derived trace gases are formed via bromoperoxidase-mediated halogenation of dissolved organic matter (DOM) in seawater. Information on DOM type in relation to the observed BrVSLS concentrations in seawater, however, is scarce. We examined the sensitivity of BrVSLS production in relation to the presence of specific DOM moieties. A total of 28 model DOM compounds in artificial seawater were treated with vanadium bromoperoxidase (V-BrPO). Our results show a clear dependence of BrVSLS production on DOM type. In general, molecules that comprise a large fraction of the bulk DOM pool did not noticeably affect BrVSLS production. Only specific cell metabolites and humic acid appeared to significantly enhance BrVSLS production. Amino acids and lignin phenols suppressed enzyme-mediated BrVSLS production and may instead have formed halogenated nonvolatile molecules. Dibromomethane production was not observed in any experiments, suggesting it is not produced by the same pathway as the other BrVSLS. Our results suggest that regional differences in DOM composition may explain the observed BrVSLS concentration variability in the global ocean. Ultimately, BrVSLS production and concentrations are likely affected by DOM composition, reactivity, and cycling in the ocean.

  3. A trait-based approach to understanding marine communities composition, assembly and diversity

    DEFF Research Database (Denmark)

    Pécuchet, Lauréne

    are characterised by their taxonomic diversity, such as their species richness or the evenness in their abundances. However, there is growing evidence that it is not the taxonomic identity of the species per se that control its presence and abundance in a given environment but its characteristics. Species traits......, we studied the diversity and the processes influencing the composition of demersal fish communities in the Baltic Sea. While species richness was sharply decreasing from the saline Kattegat to the brackish Gdansk Bay, trait richness tended to decrease at a lower rate. We found that the species co...... acting on the species. The strategies’ prevalence exhibited strong geographical patterns which could be explained by spatial variability in annual sea surface temperature, temperature seasonality, depth and fishing intensity. Due to their tight coupling to the environment, notably temperature and fishing...

  4. Marine litter in the upper São Vicente submarine canyon (SW Portugal): Abundance, distribution, composition and fauna interactions.

    Science.gov (United States)

    Oliveira, Frederico; Monteiro, Pedro; Bentes, Luis; Henriques, Nuno Sales; Aguilar, Ricardo; Gonçalves, Jorge M S

    2015-08-15

    Marine litter has become a worldwide environmental problem, tainting all ocean habitats. The abundance, distribution and composition of litter and its interactions with fauna were evaluated in the upper S. Vicente canyon using video images from 3 remote operated vehicle exploratory dives. Litter was present in all dives and the abundance was as high as 3.31 items100m(-1). Mean abundance of litter over rock bottom was higher than on soft substrate. Mean litter abundance was slightly higher than reported for other canyons on the Portuguese margin, but lower in comparison to more urbanized coastal areas of the world. Lost fishing gear was the prevalent type of litter, indicating that the majority of litter originates from maritime sources, mainly fishing activity. Physical contact with sessile fauna and entanglement of specimens were the major impacts of lost fishing gear. Based on the importance of this region for the local fishermen, litter abundance is expected to increase. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Silicon isotope fractionation by marine sponges and the reconstruction of the silicon isotope composition of ancient deep water

    Science.gov (United States)

    de La Rocha, Christina L.

    2003-05-01

    The silicon isotope composition (δ30Si) of biogenic opal provides a view of the silica cycle at times in the past. Reconstructions require the knowledge of silicon isotope fractionation during opal biomineralization. The δ30Si of specimens of hexactinellid sponges and demosponges growing in the modern ocean ranged from -1.2‰ to -3.7‰ (n = 6), corresponding to the production of opal that has a δ30Si value 3.8‰ ± 0.8‰ more negative than seawater silicic acid and a fractionation factor (α) of 0.9964. This is three times the fractionation observed during opal formation by marine diatoms and terrestrial plants and is the largest fractionation of silicon isotopes observed for any natural process on Earth. The δ30Si values of sponge spicules across the Eocene-Oligocene boundary at Ocean Drilling Program Site 689 on Maud Rise range from -1.1‰ to -3.0‰, overlapping the range observed for sponges growing in modern seawater.

  6. [Fatty acids composition of the marine snails Phyllonotus pomum and Chicoreus brevifrons (Muricidae)].

    Science.gov (United States)

    D'Armas, Haydelba; Yáñez, Dayanis; Reyes, Dilia; Salazar, Gabriel

    2010-06-01

    Muricid species of P. pomum and C. brevifrons are of economic importance in the Caribbean. This study includes a comparative evaluation of fatty acid content in the total lipid composition of Phyllonotus pomum and Chicoreus brevifrons. Snail samples were collected during the rainy, dry and transition seasons, in Punta Arena, Sucre (Venezuela). Total lipids were extracted and the specific fatty acid contents were analyzed by gas chromatography. Lipid concentrations varied between 0.87 and 1.85%, with minimum and maximum values corresponding to C. brevifrons collected during rainy and dry seasons, respectively. In the case of total lipids, a high concentration of unsaturated fatty acids (57.21-70.05%) was observed followed by saturated fatty acids (20.33-31.94%), during all seasons. The polyunsaturated occurred in higher proportion among the unsaturated fatty acids, except for P. pomum which showed higher proportion of monounsaturated fatty acids (38.95%) during the transition season. The prevailing fatty acids were: C14:0, C16:0, C18:0, C20:1, C22:1 omega-11, C22:1 omega-9, C18:3 omega-3, C20:5 omega-3 and C22:6 omega-3, among which docosahexaenoic acid was the predominant polyunsaturated fatty acid, showing values between 4.62 and 33.11%. The presence of high concentrations of polyunsaturated fatty acids found in P. Pomum and C. brevifrons allow their recommendation for human consumption with appropriate resource utilization.

  7. Yields, photosynthetic efficiencies, and proximate chemical composition of dense cultures of marine microalgae. A subcontract report

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, W.H.; Seibert, D.L.R.; Alden, M.; Eldridge, P.; Neori, A.

    1983-07-01

    The yields, photosynthetic efficiencies, and proximate composition of several microalgae were compared in dense cultures grown at light intensities up to 70% sunlight. Yields ranged from 3.4 to 21.7 g dry weight/m/sup 2/ day. The highest yield was obtained with Phaeodactylum; the lowest in Botryococcus cultures. The same species had the highest and lowest efficiencies of utilization of photosynthetically active radiation. In nitrogen-sufficient cells of all but one species, most of the dry weight consisted of protein. Lipid content of all species was 20 to 29%, and carbohydrate content 11 to 23%. Lipid content increased somewhat in N-deficient Phaeodactylum and Isochrysis cells, but decreased in deficient Monallanthus cells. Because the overall dry weight yield was reduced by deficiency, lipid yields did not increase. However, since the carbohydrate content increased to about 65% in N-deficient Dunaliella and Tetraselmis cells, the carbohydrate yield increased. In Phaeodactylum the optimum light intensity was about 40% of full sunlight. Most experimets with this alga included a CUSO/sub 4/ filter to decrease infrared irradiance. When this filter was removed, the yield increased because more red light in the photosynthetically active spectral range was included. These results should prove useful to workers attempting to maximize yields and efficiencies, but additional studies are needed. 69 references, 27 figures, 18 tables.

  8. A novel kind of solid rocket propellant

    Energy Technology Data Exchange (ETDEWEB)

    Lo, R.E. [Berlin University of Technology (Germany). Rocket Technology at the Aerospace Institute (ILR)

    1998-09-01

    Cryogenic Solid Propellants (CSPs) combine the simplicity of conventional solid propulsion with the high performance of liquid propulsion. By introducing materials that require cooling for remaining solid, CSPs offer an almost unlimited choice of propellant constituents that mights be selected with respect to specific impulse, density or environmental protection. The prize to be paid for these advantages is the necessity of constant cooling and the requirement of special design features that provide combustion control by moving from deflagration to hybrid like boundary layer combustion. This is achieved by building the solid propellant grains out of macroscopic elements rather than using the quasi homogeneous mixture of conventional composites. The elements may be coated, providing protection and support. Different elements may be designed for individual tasks and serve as modules for ignition, sustained combustion, gas generation, combustion efficiency enhancement, etc. Modular dissected grains offer many new ways of interaction inside the combustion chamber and new degrees of freedom for the designer of such `multiple internal hybrid grains`. At a preliminary level, a study finished in Germany 1997 demonstrated large payload gains when the US space Shuttle and the ARIANE 5 boosters were replaced by CSP-boosters. A very preliminary cost analysis resulted in development costs in the usual magnitude (but not in higher ones). Costs of operation were identified as crucial, but not established. Some experimental work in Germany is scheduled to begin in 1998, almost all details in this article (and many more that were not mentioned - most prominent cost analyses of CSP development and operations) wait for deeper analysis and verification. Actually, a whole new world new of world of chemical propulsion awaits exploration. The topic can be looked up and discussed at the web site of the Advanced Propulsion Workshop of the International Academy of Astronautics. The author

  9. Propeller Flaps: A Literature Review.

    Science.gov (United States)

    Sisti, Andrea; D'Aniello, Carlo; Fortezza, Leonardo; Tassinari, Juri; Cuomo, Roberto; Grimaldi, Luca; Nisi, Giuseppe

    2016-01-01

    Since their introduction in 1991, propeller flaps are increasingly used as a surgical approach to loss of substance. The aim of this study was to evaluate the indications and to verify the outcomes and the complication rates using this reconstructing technique through a literature review. A search on PubMed was performed using "propeller flap", "fasciocutaneous flap", "local flap" or "pedicled flap" as key words. We selected clinical studies using propeller flaps as a reconstructing technique. We found 119 studies from 1991 to 2015. Overall, 1,315 propeller flaps were reported in 1,242 patients. Most frequent indications included loss of substance following tumor excision, repair of trauma-induced injuries, burn scar contractures, pressure sores and chronic infections. Complications were observed in 281/1242 patients (22.6%) occurring more frequently in the lower limbs (31.8%). Partial flap necrosis and venous congestion were the most frequent complications. The complications' rate was significantly higher in infants (70 years old) but there was not a significant difference between the sexes. Trend of complication rate has not improved during the last years. Propeller flaps showed a great success rate with low morbidity, quick recovery, good aesthetic outcomes and reduced cost. The quality and volume of the transferred soft tissue, the scar orientation and the possibility of direct donor site closure should be considered in order to avoid complications. Indications for propeller flaps are small- or medium-sized defects located in a well-vascularized area with healthy surrounding tissues. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  10. Laser-propelled ram accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sasoh, A. [Tohoku Univ., Sendai (Japan). Inst. of Fluid Science

    2000-11-01

    The concept of 'laser-propelled ram accelerator (L-RAMAC)' is proposed. Theoretically it is capable of achieving a higher launch speed than that by a chemical ram accelerator because a higher specific energy can be input to the propellant gas. The laser beam is supplied through the muzzle, focused as an annulus behind the base of the projectile. The performance of L-RAMAC is analized based on generalized Rankine-Hugoniot relations, suggesting that a superorbital muzzle speed is achievable out of this device. (orig.)

  11. 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...

  12. 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.

  13. Seawater Immersion of GEM II Propellant

    National Research Council Canada - National Science Library

    Merrill, Calude

    1999-01-01

    ... (% AP lost/week aged in seawater) and intercepts that depend on sample size. Friction and impact data on dried aged propellant samples showed no increased burning hazard compared with propellant not exposed to water...

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

    DEFF Research Database (Denmark)

    Shin, K. W.; Andersen, Poul

    2015-01-01

    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...

  15. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris.

    Science.gov (United States)

    Oberbeckmann, Sonja; Osborn, A Mark; Duhaime, Melissa B

    2016-01-01

    Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5-6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae-all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the PET

  16. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris

    Science.gov (United States)

    Osborn, A. Mark

    2016-01-01

    Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5–6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae—all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the

  17. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris.

    Directory of Open Access Journals (Sweden)

    Sonja Oberbeckmann

    Full Text Available Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate (PET drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5-6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae-all known to degrade complex carbon substrates and diatoms (e.g. Coscinodiscophytina, Bacillariophytina. The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact

  18. Combustion characteristics of SMX and SMX based propellants

    Science.gov (United States)

    Reese, David A.

    This work investigates the combustion of the new solid nitrate ester 2,3-hydroxymethyl-2,3-dinitro-1,4-butanediol tetranitrate (SMX, C6H 8N6O16). SMX was synthesized for the first time in 2008. It has a melting point of 85 °C and oxygen balance of 0% to CO 2, allowing it to be used as an energetic additive or oxidizer in solid propellants. In addition to its neat combustion characteristics, this work also explores the use of SMX as a potential replacement for nitroglycerin (NG) in double base gun propellants and as a replacement for ammonium perchlorate in composite rocket propellants. The physical properties, sensitivity characteristics, and combustion behaviors of neat SMX were investigated. Its combustion is stable at pressures of up to at least 27.5 MPa (n = 0.81). The observed flame structure is nearly identical to that of other double base propellant ingredients, with a primary flame attached at the surface, a thick isothermal dark zone, and a luminous secondary flame wherein final recombination reactions occur. As a result, the burning rate and primary flame structure can be modeled using existing one-dimensional steady state techniques. A zero gas-phase activation energy approximation results in a good fit between modeled and observed behavior. Additionally, SMX was considered as a replacement for nitroglycerin in a double base propellant. Thermochemical calculations indicate improved performance when compared with the common double base propellant JA2 at SMX loadings above 40 wt-%. Also, since SMX is a room temperature solid, migration may be avoided. Like other nitrate esters, SMX is susceptible to decomposition over long-term storage due to the presence of excess acid in the crystals; the addition of stabilizers (e.g., derivatives of urea) during synthesis should be sufficient to prevent this. the addition of Both unplasticized and plasticized propellants were formulated. Thermal analysis of unplasticized propellant showed a distinct melt

  19. Seasonal variation in marine C:N:P stoichiometry: can the composition of seston explain stable Redfield ratios?

    Directory of Open Access Journals (Sweden)

    H. Frigstad

    2011-10-01

    Full Text Available Seston is suspended particulate organic matter, comprising a mixture of autotrophic, heterotrophic and detrital material. Despite variable proportions of these components, marine seston often exhibits relatively small deviations from the Redfield ratio (C:N:P = 106:16:1. Two time-series from the Norwegian shelf in Skagerrak are used to identify drivers of the seasonal variation in seston elemental ratios. An ordination identified water mass characteristics and bloom dynamics as the most important drivers for determining C:N, while changes in nutrient concentrations and biomass were most important for the C:P and N:P relationships. There is no standardized method for determining the functional composition of seston and the fractions of POC, PON and PP associated with phytoplankton, therefore any such information has to be obtained by indirect means. In this study, a generalized linear model was used to differentiate between the live autotrophic and non-autotrophic sestonic fractions, and for both stations the non-autotrophic fractions dominated with respective annual means of 76 and 55%. This regression model approach builds on assumptions (e.g. constant POC:Chl-a ratio and the robustness of the estimates were explored with a bootstrap analysis. In addition the autotrophic percentage calculated from the statistical model was compared with estimated phytoplankton carbon, and the two independent estimates of autotrophic percentage were comparable with similar seasonal cycles. The estimated C:nutrient ratios of live autotrophs were, in general, lower than Redfield, while the non-autotrophic C:nutrient ratios were higher than the live autotrophic ratios and above, or close to, the Redfield ratio. This is due to preferential remineralization of nutrients, and the P content mainly governed the difference between the sestonic fractions. Despite the seasonal variability in seston composition and the generally low contribution of autotrophic

  20. Changes in abundance and composition of anthropogenic marine debris on the continental slope off the Pacific coast of northern Japan, after the March 2011 Tohoku earthquake

    International Nuclear Information System (INIS)

    Goto, Tomoaki; Shibata, Haruka

    2015-01-01

    Highlights: • Benthic marine debris on continental slope off northeastern Japan quantified. • Low density of sea-base sourced debris dominant until 2011 Tohoku earthquake. • Increase in marine debris after the earthquake indicated by post-2011 tsunami survey. • Much increase in land-base sourced debris mainly due to 2011 tsunami. • Additional sources of land-based debris during post-tsunami survey implied. - Abstract: Abundance and composition of anthropogenic marine debris were assessed on the basis of six bottom trawl surveys conducted on the continental slope off Iwate Prefecture, Pacific coast of northern Japan, in 2003, 2004 and 2011, and the temporal changes due to the Tohoku earthquake and tsunami in March 2011 evaluated. In 2003 and 2004, 54–94 items km −2 of marine debris, dominated by sea-base sourced items mainly comprising fishing gear and related items from adjacent fishing grounds on the continental shelf, were quantified. In the post-earthquake period, the density increased drastically to 233–332 items km −2 , due to an increase in land-base sourced items generated by the tsunami. However, a major increase in abundance after the disaster, compared to the total amount of tsunami debris swept into the sea, was not found. Additional sources of land-based debris from the adjacent continental shelf are suggested in the present waters

  1. 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...

  2. Plasma ignition of LOVA propellants

    NARCIS (Netherlands)

    Driel, C.A. van; Boluijt, A.G.; Schilt, A.

    2010-01-01

    Ignition experiments were performed using a gun simulator which is equipped with a burst disk. This equipment facilitates the application of propellant loading densities which are comparable to those applied in regular ammunitions. For this study the gun simulator was equipped with a plasma jet

  3. 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.

  4. Compositional Similarities and Differences between Transparent Exopolymer Particles (TEP) from two Marine Bacteria and two Marine Algae: Significance to Surface Biofouling

    KAUST Repository

    Li, Sheng

    2015-06-12

    Transparent-exopolymer-particles (TEP) have been recently identified as a significant contributor to surface biofouling, such as on reverse osmosis (RO) membranes. TEP research has mainly focused on algal TEP/TEP precursors while limited investigations have been conducted on those released by bacteria. In this study, TEP/TEP precursors derived from both algae and bacteria were isolated and then characterized to investigate their similarities and/or differences using various advanced analytical techniques, thus providing a better understanding of their potential effect on biofouling. Bacterial TEP/TEP precursors were isolated from two species of marine bacteria (Pseudidiomarina homiensis and Pseudoalteromonas atlantica) while algal TEP/TEP precursors were isolated from two marine algae species (Alexandrium tamarense and Chaetoceros affinis). Results indicated that both isolated bacterial and algal TEP/TEP precursors were associated with protein-like materials, and most TEP precursors were high-molecular-weight biopolymers. Furthermore all investigated algal and bacterial TEP/TEP precursors showed a lectin-like property, which can enable them to act as a chemical conditioning layer and to agglutinate bacteria. This property may enhance surface biofouling. However, both proton nuclear magnetic resonance (NMR) spectra and the nitrogen/carbon (N/C) ratios suggested that the algal TEP/TEP precursors contained much less protein content than the bacterial TEP/TEP precursors. This difference may influence their initial deposition and further development of surface biofouling.

  5. Studies of marine macroalgae: saline desert water cultivation and effects of environmental stress on proximate composition. Final subcontract report. [Gracilaria tikvahiae; Ulva lactuca

    Energy Technology Data Exchange (ETDEWEB)

    Ryther, J.H.; DeBusk, T.A.; Peterson, J.E.

    1985-11-01

    The results presented in this report address the growth potential of marine macroalgae cultivated in desert saline waters, and the effects of certain environmental stresses (e.g., nitrogen, salinity, and temperature) on the proximate composition of several marine macroalgae. Two major desert saline water types were assayed for their ability to support the growth of Gracilaria, Ulva, and Caulerpa. Both water types supported short term growth, but long term growth was not supported. Carbohydrate levels in Gracilaria were increased by cultivation under conditions of high salinity, low temperature, and low nitrogen and phosphorous availability. Data suggests that it may be possible to maximize production of useful proximate constituents by cultivating the algae under optimum conditions for growth, and then holding the resulting biomass under the environmental conditions which favor tissue accumulation of the desired storage products. 16 refs., 21 figs., 19 tabs.

  6. Mind the gut : Genomic insights to population divergence and gut microbial composition of two marine keystone species

    NARCIS (Netherlands)

    Fietz, Katharina; Rye Hintze, Christian Olaf; Skovrind, Mikkel; Kjærgaard Nielsen, Tue; Limborg, Morten T; Krag, Marcus A; Palsbøll, Per J; Hestbjerg Hansen, Lars; Rask Møller, Peter; Gilbert, M Thomas P

    2018-01-01

    BACKGROUND: Deciphering the mechanisms governing population genetic divergence and local adaptation across heterogeneous environments is a central theme in marine ecology and conservation. While population divergence and ecological adaptive potential are classically viewed at the genetic level, it

  7. Influence of marine aerosols and aerotechnogenic load on chemical composition of rainwaters on small islands (ludas) of the White Sea

    Science.gov (United States)

    Gorbacheva, Tamara; Mazukhina, Svetlana; Isaeva, Ludmila; Shumilov, Oleg

    2013-04-01

    In June 2001 intensive monitoring plots were established on the island part of Kandalaksha Bay of the White Sea (the island Tonnaya Luda; 67o06'60"N; 32o24'12"E) with the installation of stationary rainwater collectors. The purpose was studying the chemical composition of rain waters in the zone of cumulative influence of marine aerosols and aerotechnogenic load. Water sampling was carried out monthly during the vegetative season of 2001 and 2002. pH of rain water was determined by potentiometric method without preliminary filtration. The samples were passed through the paper filter with the pore diameter of 1-2.5 microns, the analysis of filtrate carried out by methods of atomic emission spectrometry (K, Na) and atomic absorption spectrometry (Ca, Mg, Zn, Mn, Cu, Ni, Al, Fe), total P and P of phosphates, Si and NH4+ - by photocolorimetry, total carbon - by bichromate method, NO3-, SO42-, Cl--by ion exchange chromatography method. Balance method was chosen as a research basis to determine the interrelation of rain water organic matter and dynamics of its redistribution under the influence of natural and technogenic factors. The difference between the cations sum (including NH4+and H+) and mineral acids anions sum (SO42-, Cl-, NO3-) was identified as organic acids anions concentration (μeq l-1). The level of Na, Cl-, K, Ca, Mg, SO42-, Sr in rainwaters on the island and the remote areas is indicative of the possible influence of marine aerosols on the island part of the White Sea. The increase of Al, Cu, Ni, Cd, Co concentrations in rainwaters up to one order against the background values points to the cumulative influence of the emissions of industrial enterprises located in the region. The relative stability of pH values of rain waters during all seasons indicates to the buffer action of weak organic acids anions. The correlation analysis of ionic structure in normal concentrations has allowed us to estimate the distribution of the cationic part from the

  8. 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.

  9. Paleomagnetic direction and paleointensity variations during the Matuyama-Brunhes polarity transition from a marine succession in the Chiba composite section of the Boso Peninsula, central Japan

    Science.gov (United States)

    Okada, Makoto; Suganuma, Yusuke; Haneda, Yuki; Kazaoka, Osamu

    2017-03-01

    The youngest geomagnetic polarity reversal, the Matuyama-Brunhes (M-B) boundary, provides an important plane of data for sediments, ice cores, and lavas. The geomagnetic field intensity and directional changes that occurred during the reversal also provide important information for understanding the dynamics of the Earth's outer core, which generates the magnetic field. However, the reversal process is relatively rapid in terms of the geological timescale; therefore, adequate temporal resolution of the geomagnetic field record is essential for addressing these topics. Here, we report a new high-resolution paleomagnetic record from a continuous marine succession in the Chiba composite section of the Kokumoto Formation of the Kazusa Group, Japan, that reveals detailed behaviors of the virtual geomagnetic poles (VGPs) and relative paleointensity changes during the M-B polarity transition. The resultant relative paleointensity and VGP records show a significant paleointensity minimum near the M-B boundary, which is accompanied by a clear "polarity switch." A newly obtained high-resolution oxygen isotope chronology for the Chiba composite section indicates that the M-B boundary is located in the middle of marine isotope stage (MIS) 19 and yields an age of 771.7 ka for the boundary. This age is consistent with those based on the latest astronomically tuned marine and ice core records and with the recalculated age of 770.9 ± 7.3 ka deduced from the U-Pb zircon age of the Byk-E tephra. To the best of our knowledge, our new paleomagnetic data represent one of the most detailed records on this geomagnetic field reversal that has thus far been obtained from marine sediments and will therefore be key for understanding the dynamics of the geomagnetic dynamo and for calibrating the geological timescale.[Figure not available: see fulltext.

  10. Changes in microbial composition and the prevalence of foodborne pathogens in crab marinated in soy sauce produced by six manufacturing plants.

    Science.gov (United States)

    Kim, Sun Ae; Choi, Eun Sook; Kim, Nam Hee; Kim, Hye Won; Lee, Na Young; Cho, Tae Jin; Jo, Jun Il; Kim, Soon Han; Lee, Soon Ho; Ha, Sang Do; Rhee, Min Suk

    2017-04-01

    The present study examined the changes in microbiological composition during the production process of crab marinated in soy sauce, potential microbial hazards, potential contamination routes and effective critical control points. Crab and soy sauce samples were obtained from six different manufacturing plants at different stages, and their microbiological content was comprehensively assessed by quantitative and qualitative analyses. The results revealed the following: (1) the final products contained 4.0 log colony-forming units (CFU) g -1 aerobic plate counts (APCs) and 1.1 log CFU g -1 coliforms, which may have been introduced from the raw materials (the level of APCs in raw crab and soy sauce mixed with other ingredients was 3.8 log CFU g -1 and 4.0 log CFU mL -1 respectively); (2) marination of crab in soy sauce may allow cross-contamination by coliforms; (3) only Bacillus cereus and Staphylococcus aureus were qualitatively detected in samples at different stages of manufacture (detection rate of 28 and 5.6% respectively), and these bacteria may impact the microbiological quality and safety of crab marinated in soy sauce; and (4) bacterial counts were either maintained or increased during the manufacturing process (suggesting that no particular step can be targeted to reduce bacterial counts). Proper management of raw materials and the marination process are effective critical control points, and alternative interventions may be needed to control bacterial quantity. The results provide important basic information about the production of crab marinated in soy sauce and may facilitate effective implementation of sanitary management practices in related industries and research fields. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  11. Fatigue degradation and failure of rotating composite structures - Materials characterisation and underlying mechanisms

    DEFF Research Database (Denmark)

    Gamstedt, Kristofer; Andersen, Svend Ib Smidt

    2001-01-01

    The present review concerns rotating composite structures, in which fatigue degradation is of key concern for in-service failure. Such applications are for instance rotor blades in wind turbines, helicopter rotor blades, flywheels for energy storage,marine and aeronautical propellers, and rolls...... for paper machines. The purpose is to identify areas where impending efforts should be made to make better use of composite materials in these applications. In order to obtain better design methodologies,which would allow more reliable and slender structures, improved test methods are necessary. Furthermore...

  12. Experimental research on air propellers

    Science.gov (United States)

    Durand, William F

    1918-01-01

    The purposes of the experimental investigation on the performance of air propellers described in this report are as follows: (1) the development of a series of design factors and coefficients drawn from model forms distributed with some regularity over the field of air-propeller design and intended to furnish a basis of check with similar work done in other aerodynamic laboratories, and as a point of departure for the further study of special or individual types and forms; (2) the establishment of a series of experimental values derived from models and intended for later use as a basis for comparison with similar results drawn from certain selected full-sized forms and tested in free flight.

  13. Chemical Composition of the Graphitic Black Carbon Fraction in Riverine and Marine Sediments at Submicron Scales using Carbon X-ray Spectromicroscopy

    International Nuclear Information System (INIS)

    Haberstroh, P.; Brandes, J.; Gelinas, Y.; Dickens, A.; Wirick, S.; Cody, G.

    2006-01-01

    The chemical composition of the graphitic black carbon (GBC) fraction of marine organic matter was explored in several marine and freshwater sedimentary environments along the west coast of North America and the Pacific Ocean. Analysis by carbon x-ray absorption near edge structure (C-XANES) spectroscopy and scanning transmission x-ray microscopy (STXM) show the GBC-fraction of Stillaguamish River surface sediments to be dominated by more highly-ordered and impure forms of graphite, together forming about 80% of the GBC, with a smaller percent of an aliphatic carbon component. Eel River Margin surface sediments had very little highly-ordered graphite, and were instead dominated by amorphous carbon and to a lesser extent, impure graphite. However, the GBC of surface sediments from the Washington State Slope and the Mexico Margin were composed almost solely of amorphous carbon. Pre-anthropogenic, highly-oxidized deep-sea sediments from the open Equatorial Pacific Ocean contained over half their GBC in different forms of graphite as well as highly-aliphatic carbon, low aromatic/highly-acidic aliphatic carbon, low aromatic/highly aliphatic carbon, and amorphous forms of carbon. Our results clearly show the impact of graphite and amorphous C phases in the BC fraction in modern riverine sediments and nearby marine shelf deposits. The pre-anthropogenic Equatorial Pacific GBC fraction is remarkable in the existence of highly-ordered graphite

  14. A Study of Interaction of Laser Light with Small Drops of XM46 Propellant and Related Liquids

    National Research Council Canada - National Science Library

    Juvan, Kim

    1999-01-01

    Stimulated Raman spectroscopy (SRS) has been explored as a possible diagnostic tool to determine if observable changes in composition occur in the liquid gun propellants containing hydroxyl ammonium nitrate (HAN...

  15. Chemical composition of aerosol, sea fog, and rainwater in the marine boundary layer of the northwestern North Pacific and its marginal seas

    Science.gov (United States)

    Sasakawa, Motoki; Uematsu, Mitsuo

    2002-12-01

    Samples of aerosol, sea fog, and rainwater were collected during a research cruise in the northwestern North Pacific, the Sea of Okhotsk, and the Sea of Japan in the summer of 1998. High concentrations of NO3-, nss-SO42- and NH4+ in aerosol over the Sea of Japan suggest that anthropogenic substances were transported to this region. Although the Sea of Okhotsk was covered with a clean marine air mass, the concentration of nss-SO42- was comparatively high in the aerosol samples. This nss-SO42- is probably of marine biogenic origin. The pH values of fogwater samples were measured to be fogwater collected over the Sea of Japan were higher than those in the other regions, suggesting that the sea fog scavenged anthropogenic substances. The concentration of nss-SO42- in fogwater over the Sea of Okhotsk was equivalent to that over the Sea of Japan, probably because nss-SO42- and SO2 of marine biogenic origin were scavenged by the sea fog over the Sea of Okhotsk. The pH values of rainwater samples ranged from 6.1 to 7.2 during the cruise, and acidification of the rain was not significant. The concentrations of nss-Ca2+ in the rainwater were higher than those of the fogwater. This suggests that the rain-scavenged continental CaCO3 may have existed above the lower marine boundary layer, where sea fog appeared. Comparisons of the composition of aerosol and fogwater indicated that coarse particles, such as sea salts predominantly act as condensation nuclei of sea fog droplets rather than fine particles such as (NH4)2SO4.

  16. Persistent organic pollutants in marine fish from Yongxing Island, South China Sea: levels, composition profiles and human dietary exposure assessment.

    Science.gov (United States)

    Sun, Yu-Xin; Hao, Qing; Xu, Xiang-Rong; Luo, Xiao-Jun; Wang, Shuai-Long; Zhang, Zai-Wang; Mai, Bi-Xian

    2014-03-01

    Little data is available on the bioaccumulation of persistent organic pollutants (POPs) in marine organisms from South China Sea (SCS). Five marine fish species were collected from Yongxing Island, SCS to investigate the presence of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs). PBDEs, PCBs, and DDTs concentrations ranged from 2.0-117, 6.3-199, and 9.7-5831 ng g(-1) lw, respectively. In general, contaminants measured in this study were at the lower end of the global range. Concentrations of PBDEs and PCBs were significantly correlated in fish samples, implying that PBDEs are as prevalent as PCBs in Yongxing Island. Among the five fish species studied, yellow striped goatfish had the highest concentrations of PBDEs, PCBs, and DDTs, probably attributed to its different living and feeding habits. The contaminant distribution pattern indicated that agrochemical source is more important than industrial source in Yongxing Island, SCS. The average estimated daily intakes of PBDEs, PCBs, and DDTs via fish consumption by local residents in the coastal areas of South China ranged from 1.42-5.91, 3.20-13.3, and 8.08-33.6 ng d(-1), which were lower than those in previous studies, suggesting that consumption of marine fish in Yongxing Island, SCS, might not subject local residents to significant health risk as far as POPs are concerned. This is the first study to report the occurrence of POPs in marine biota from SCS. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Rocket propellants with reduced smoke and high burning rates

    Energy Technology Data Exchange (ETDEWEB)

    Menke, K.; Eisele, S. [Fraunhofer-Institut fuer Chemische Technologie (ICT), Pfinztal-Berghausen (Germany)

    1997-07-01

    Rocket propellants with reduced smoke and high burning rates recommend themselves for use in a rocket motor for high accelerating tactical missiles. They serve for an improved camouflage on the battle field and may enable guidance control due to the higher transmission of their rocket plume compared to traditional aluminized composite propellants. In this contribution the material based ranges of performance and properties of three non aluminized rocket propellants will be introduced and compared to each other. The selected formulations based on AP/HTPB; AP/PU/TMETN and AP/HMX/GAP/TMETN have roughly the same specific impulse of I{sub SP}=2430 Ns/kg at 70:1 expansion ratio. The burning rates in the pressure range from 10-18 MPa vary from to 26-33 mm/s for the AP/HTPB propellant, 52-68 mm/s for the formulation based on AP/PU/TMETN and 28-39 mm/s for the propellant based on AP/HMX/GAP. With 58% and 20% AP-contents the propellants with nitrate ester plasticizers create a much smaller secondary signature than the AP/HTPB representative containing 85% AP. Their disadvantage, however, is the connection of high performance to a high level of energetic plasticizer. For this reason, the very fast burning propellant based on AP/PU/TMETN is endowed with a low elastic modulus and is limited to a grain configuration which isn`t exposed too much to the fast and turbulent airstream. The mechanical properties of the AP/HMX/GAP-propellant are as good or better as those of the AP/HTPB propellant. The first one exhibits the same performance and burn rates as the composite representative but produces only one fifth of HCl exhaust. For this reason it is recommended for missile applications, which must have high accelerating power together with a significantly reduced plume signature and smoke production. (orig.) [Deutsch] Rauchreduzierte Festtreibstoffe mit hohen Abbrandgeschwindigkeiten bieten sich fuer den Antrieb hochbeschleunigender taktischer Flugkoerper an, da sie gegenueber

  18. A theoretical and experimental investigation of propeller performance methodologies

    Science.gov (United States)

    Korkan, K. D.; Gregorek, G. M.; Mikkelson, D. C.

    1980-01-01

    This paper briefly covers aspects related to propeller performance by means of a review of propeller methodologies; presentation of wind tunnel propeller performance data taken in the NASA Lewis Research Center 10 x 10 wind tunnel; discussion of the predominent limitations of existing propeller performance methodologies; and a brief review of airfoil developments appropriate for propeller applications.

  19. The influence of the choice of propeller design tool on propeller performance

    OpenAIRE

    Skåland, Edvard Knutsen

    2016-01-01

    In this master thesis different propeller design and analysis methods are presented and compared in terms of the accuracy and computational efficiency of their theory. These methods include lifting line, vortex lattice lifting surface and panel methods. A propeller design program based on lifting line theory was developed by the author. This program has been used together with the propeller design programs OpenProp and AKPD to make six propeller designs. The designs are based o...

  20. 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...

  1. 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...

  2. Injection dynamics of gelled propellants

    Science.gov (United States)

    Yoon, Changjin

    Gel propellants have been recognized as attractive candidates for future propulsion systems due to the reduced tendency to spill and the energy advantages over solid propellants. One of strong benefits emphasized in gel propellant applications is a throttling capability, but the accurate flow control is more complicated and difficult than with conventional Newtonian propellants because of the unique rheological behaviors of gels. This study is a computational effort directed to enhance understanding of the injector internal flow characteristics for gel propellants under rocket injection conditions. In simulations, the emphasized rheology is a shear-thinning which represents a viscosity decrease with increasing a shear rate. It is described by a generalized Newtonian fluid constitutive equation and Carreau-Yasuda model. Using this rheological model, two injection schemes are considered in the present study: axially-fed and cross-fed injection for single-element and multi-element impinging injectors, respectively. An axisymmetric model is developed to describe the axially-fed injector flows and fully three-dimensional model is utilized to simulate cross-fed injector flows. Under axially-fed injection conditions investigated, three distinct modes, an unsteady, steady, and hydraulic flip mode, are observed and mapped in terms of Reynolds number and orifice design. In an unsteady mode, quasi-periodic oscillations occur near the inlet lip leading mass pulsations and viscosity fluctuations at the orifice exit. This dynamic behavior is characterized using a time-averaged discharge coefficient, oscillation magnitude and frequency by a parametric study with respect to an orifice design, Reynolds number and rheology. As a result, orifice exit flows for gel propellants appear to be significantly influenced by a viscous damping and flow resistance due to a shear thinning behavior and these are observed in each factors considered. Under conditions driven by a manifold crossflow

  3. A dataset on the species composition of amphipods (Crustacea) in a Mexican marine national park: Alacranes Reef, Yucatan

    OpenAIRE

    Paz,Carlos; Simões,Nuno; Pech,Daniel

    2018-01-01

    Abstract Background Alacranes Reef was declared as a National Marine Park in 1994. Since then, many efforts have been made to inventory its biodiversity. However, groups such as amphipods have been underestimated or not considered when benthic invertebrates were inventoried. Here we present a dataset that contributes to the knowledge of benthic amphipods ( Crustacea , Peracarida ) from the inner lagoon habitats from the Alacranes Reef National Park, the largest coral reef ecosystem in the Gul...

  4. Determination of multi-element composition of Vietnamese marine sediment and tuna fish by k0-standardized neutron activation analysis

    International Nuclear Information System (INIS)

    Manh-Dung Ho; Quang-Thien Tran; Van-Doanh Ho; Thi-Sy Nguyen

    2016-01-01

    The k 0 -standardized neutron activation analysis (k 0 -NAA) has been applied for determination of multiple elements (25 elements: Al, As, Ba, Br, Ca, Cl, Co, Cr, Cs, Cu, Eu, Fe, Hg, K, La, Mg, Na, Rb, Sc, Se, Sm, Th, Ti, V and Zn) in marine sediment and tuna fish. About 50 marine sediment and 9 tuna fish samples were collected in two coastal areas of Vietnam. The health risk index (HRI) values of As and Br were higher than 1.0 for the tuna fish. Also, HRI value of Hg was 8.92 × 10 -1 indicating a relatively high potential health risk, whiles Co and Mn with HRIs = 1.56 × 10 -4 and 8.56 × 10 -4 , respectively, have the lowest potential health risks. Average enrichment factors using Al as a reference element (EF Al ) were higher than 1.5 for Eu, La, Zn, Th, Cs and As in which the highest EF Al value for As was higher than 10. This study showed that the HRI value of As in the tuna fish correlated positively with the EF Al value for the element in the marine sediment. (author)

  5. 78 FR 4038 - Critical Parts for Airplane Propellers

    Science.gov (United States)

    2013-01-18

    ... manufacturers are not required to provide information concerning propeller critical part design, manufacture, or... engineering, manufacturing, and service management processes should provide clear information for propeller... manufacture critical parts for airplane propellers update their manuals to record engineering, manufacture...

  6. 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,

  7. Composites

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1983-01-01

    This chapter discusses the roles of composite laminates and aggregates in cryogenic technology. Filamentary-reinforced composites are emphasized because they are the most widely used composite materials. Topics considered include composite systems and terminology, design and fabrication, composite failure, high-pressure reinforced plastic laminates, low-pressure reinforced plastics, reinforced metals, selectively reinforced structures, the effect of cryogenic temperatures, woven-fabric and random-mat composites, uniaxial fiber-reinforced composites, composite joints in cryogenic structures, joining techniques at room temperature, radiation effects, testing laminates at cryogenic temperatures, static and cyclic tensile testing, static and cyclic compression testing, interlaminar shear testing, secondary property tests, and concrete aggregates. It is suggested that cryogenic composite technology would benefit from the development of a fracture mechanics model for predicting the fitness-for-purpose of polymer-matrix composite structures

  8. Tests on thirteen navy type model propellers

    Science.gov (United States)

    Durand, W F

    1927-01-01

    The tests on these model propellers were undertaken for the purpose of determining the performance coefficients and characteristics for certain selected series of propellers of form and type as commonly used in recent navy designs. The first series includes seven propellers of pitch ratio varying by 0.10 to 1.10, the area, form of blade, thickness, etc., representing an arbitrary standard propeller which had shown good results. The second series covers changes in thickness of blade section, other things equal, and the third series, changes in blade area, other things equal. These models are all of 36-inch diameter. Propellers A to G form the series on pitch ratio, C, N. I. J the series on thickness of section, and K, M, C, L the series on area. (author)

  9. Small-Scale Shock Testing of Propellants and Ingredients

    National Research Council Canada - National Science Library

    Dawley, S

    2004-01-01

    .... The use of small-scale gap testing to evaluate the shock sensitivity of individual propellant ingredients and propellant formulations is a valuable method for experimentally establishing shock...

  10. 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...

  11. 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...

  12. Deflagration of thermite - ammonium nitrate based propellant mixture

    Science.gov (United States)

    Duraes, Luisa; Morgado, Joel; Portugal, Antonio; Campos, Jose

    2001-06-01

    Reaction between iron oxide (Fe2O3) and aluminum (Al) is the reference of the classic thermite compositions. The efficency of the reaction, for a given initial composition of Fe2O3 and Al, is evaluated by the final temperature and by the mass ratio of Al2O3 /AlO in products of combustion (in condensed phase). In order to increase pressure in products of thermite reaction, the original composition is mixed, with an original twin screw extruder, with a propellant binder composed of ammonium and sodium nitrates, initialy solved in formamide (CH3NO) and mixed with a polyurethane solution. The products of combustion and pyrolysis of this binder, reacting with thermite products, generates high pressure and high temperature conditions. These experimental conditions are also predicted using THOR code. The study presents DSC and TGA results of components and mixtures, and correlates them to the ignition phenomena and reaction properties. The regression rate of combustion and final attained temperature and pressure, in a closed confinement, as a function of composition of thermite components/propellant binder, are presented and discussed. They show the influence of gaseous combustion and pyrolysis products of binder in final reaction.

  13. A Ffowcs Williams and Hawkings formulation for hydroacoustic analysis of propeller sheet cavitation

    Science.gov (United States)

    Testa, C.; Ianniello, S.; Salvatore, F.

    2018-01-01

    A novel hydroacoustic formulation for the prediction of tonal noise emitted by marine propellers in presence of unsteady sheet cavitation, is presented. The approach is based on the standard Ffowcs Williams and Hawkings equation and the use of transpiration (velocity and acceleration) terms, accounting for the time evolution of the vapour cavity attached on the blade surface. Drawbacks and potentialities of the method are tested on a marine propeller operating in a nonhomogeneous onset flow, by exploiting the hydrodynamic data from a potential-based panel method equipped with a sheet cavitation model and comparing the noise predictions with those carried out by an alternative numerical approach, documented in literature. It is shown that the proposed formulation yields a one-to-one correlation between emitted noise and sheet cavitation dynamics, carrying out accurate predictions in terms of noise magnitude and directivity.

  14. From Krill to Whale: an overview of marine fatty acids and lipid compositions

    Directory of Open Access Journals (Sweden)

    Linder Michel

    2010-07-01

    Full Text Available In this study, fatty acid compositions of phyto-zooplankton (calanoid copepod species, krill… to fish species (mackerel, sardine anchovy, salmon, shark are presented. Marine oils are essentially used for their high long-chain polyunsaturated fatty acids (LC-PUFA, namely eicosapentaenoic (EPA and docosahexaenoic (DHA for their good health impact. Due to health benefits of the omega-3, weekly fish consumption is today recommended by many authorities (FDA, AFSSA…. Capture fisheries and aquaculture supplied the world with about 110 million tonnes of food fish in 2006 (FAO 2009, providing an apparent per capita supply of 16.7 kg. It is well established that the lipid composition of fish muscle is influenced by the diet and also depends on the effects of environmental factors (temperature, oxygen concentration in sea water and endogenous medium (physiological state and individual variability. In general, cultured fish have been reported to have a softer texture than wild fish, which has been related to the differences in muscle structure, proximate composition and nutritional value. New applications of typical compounds (wax esters, squalene … or lipid classes (glycerophospholipids, ether glycerolipids, sphingophospholipids … as cosmetics, functional foods and dietary supplements will become very important in the near future with nano-structured drug carriers in pharmaceutical and biomedical areas.

  15. The impact of temperature change on the activity and community composition of sulfate-reducing bacteria in arctic versus temperate marine sediments

    DEFF Research Database (Denmark)

    Robador, Alberto; Brüchert, Volker; Jørgensen, Bo Barker

    2009-01-01

    Arctic regions may be particularly sensitive to climate warming and, consequently, rates of carbon mineralization in warming marine sediment may also be affected. Using long-term (24 months) incubation experiments at 0°C, 10°C and 20°C, the temperature response of metabolic activity and community...... composition of sulfate-reducing bacteria were studied in the permanently cold sediment of north-western Svalbard (Arctic Ocean) and compared with a temperate habitat with seasonally varying temperature (German Bight, North Sea). Short-term 35S-sulfate tracer incubations in a temperature-gradient block...... (between -3.5°C and +40°C) were used to assess variations in sulfate reduction rates during the course of the experiment. Warming of arctic sediment resulted in a gradual increase of the temperature optima (Topt) for sulfate reduction suggesting a positive selection of psychrotolerant/mesophilic sulfate...

  16. A research on polyether glycol replaced APCP rocket propellant

    Science.gov (United States)

    Lou, Tianyou; Bao, Chun Jia; Wang, Yiyang

    2017-08-01

    Ammonium perchlorate composite propellant (APCP) is a modern solid rocket propellant used in rocket vehicles. It differs from many traditional solid rocket propellants by the nature of how it is processed. APCP is cast into shape, as opposed to powder pressing it with black powder. This provides manufacturing regularity and repeatability, which are necessary requirements for use in the aerospace industry. For traditional APCP, ingredients normally used are ammonium peroxide, aluminum, Hydroxyl-terminated polybutadiene(HTPB), curing agency and other additives, the greatest disadvantage is that the fuel is too expensive. According to the price we collected in our country, a single kilogram of this fuel will cost 200 Yuan, which is about 35 dollars, for a fan who may use tons of the fuel in a single year, it definitely is a great deal of money. For this reason, we invented a new kind of APCP fuel. Changing adhesive agency from cross-linked htpb to cross linked polyether glycol gives a similar specific thrust, density and mechanical property while costs a lower price.

  17. 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

  18. 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.

  19. 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.

  20. Development of Static Balance Measurement and Correction Compound Platform for Single Blade of Controllable Pitch Propeller

    Science.gov (United States)

    Chao, Zhang; Shijie, Su; Yilin, Yang; Guofu, Wang; Chao, Wang

    2017-11-01

    Aiming at the static balance of the controllable pitch propeller (CPP), a high efficiency static balance method based on the double-layer structure of the measuring table and gantry robot is adopted to realize the integration of torque measurement and corrected polish for controllable pitch propeller blade. The control system was developed by Microsoft Visual Studio 2015, and a composite platform prototype was developed. Through this prototype, conduct an experiment on the complete process of torque measurement and corrected polish based on a 300kg class controllable pitch propeller blade. The results show that the composite platform can correct the static balance of blade with a correct, efficient and labor-saving operation, and can replace the traditional method on static balance of the blade.

  1. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2011-01-01

    Strategies are open compositions to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them in full...

  2. Composition

    DEFF Research Database (Denmark)

    2014-01-01

    Memory Pieces are open compositions to be realised solo by an improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them...

  3. 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....

  4. Noise from Two-Blade Propellers

    Science.gov (United States)

    Stowell, E Z; Deming, A F

    1936-01-01

    The two-blade propeller, one of the most powerful sources of sound known, has been studied with the view of obtaining fundamental information concerning the noise emission. In order to eliminate engine noise, the propeller was mounted on an electric motor. A microphone was used to pick up the sound whose characteristics were studied electrically. The distribution of noise throughout the frequency range, as well as the spatial distribution about the propeller, was studied. The results are given in the form of polar diagrams. An appendix of common acoustical terms is included.

  5. Experimental Research on Air Propellers III

    Science.gov (United States)

    Durand, W F; Lesley, E P

    1920-01-01

    Report presents the results of wind tunnel tests of propellers that examined the influence of the following characteristics: (1) nominal pitch ratio 1.3 combined with a certain number of the more common or standard forms and proportions; (2) driving face slightly rounded or convex; (3) change in the location of the maximum thickness ordinate of the blade section; (4) pushing forward the leading edge of the blade, thus giving a rounded convex surface on the leading side of the driving face. (5) a series of values for the constant "angle of attack" in forming propellers with radially increasing pitch. In accordance with these purposes tests were carried out on 28 propellers.

  6. 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.

  7. Thallium isotope composition of the upper continental crust and rivers - An investigation of the continental sources of dissolved marine thallium

    Science.gov (United States)

    Nielsen, S.G.; Rehkamper, M.; Porcelli, D.; Andersson, P.; Halliday, A.N.; Swarzenski, P.W.; Latkoczy, C.; Gunther, D.

    2005-01-01

    The thallium (Tl) concentrations and isotope compositions of various river and estuarine waters, suspended riverine particulates and loess have been determined. These data are used to evaluate whether weathering reactions are associated with significant Tl isotope fractionation and to estimate the average Tl isotope composition of the upper continental crust as well as the mean Tl concentration and isotope composition of river water. Such parameters provide key constraints on the dissolved Tl fluxes to the oceans from rivers and mineral aerosols. The Tl isotope data for loess and suspended riverine detritus are relatively uniform with a mean of ??205Tl = -2.0 ?? 0.3 (??205Tl represents the deviation of the 205Tl/203Tl isotope ratio of a sample from NIST SRM 997 Tl in parts per 104). For waters from four major and eight smaller rivers, the majority were found to have Tl concentrations between 1 and 7 ng/kg. Most have Tl isotope compositions very similar (within ??1.5 ??205Tl) to that deduced for the upper continental crust, which indicates that no significant Tl isotope fractionation occurs during weathering. Based on these results, it is estimated that rivers have a mean natural Tl concentration and isotope composition of 6 ?? 4 ng/kg and ??205Tl = -2.5 ?? 1.0, respectively. In the Amazon estuary, both additions and losses of Tl were observed, and these correlate with variations in Fe and Mn contents. The changes in Tl concentrations have much lower amplitudes, however, and are not associated with significant Tl isotope effects. In the Kalix estuary, the Tl concentrations and isotope compositions can be explained by two-component mixing between river water and a high-salinity end member that is enriched in Tl relative to seawater. These results indicate that Tl can display variable behavior in estuarine systems but large additions and losses of Tl were not observed in the present study. Copyright ?? 2005 Elsevier Ltd.

  8. Growth, Fatty Acid, and Lipid Composition of Marine Microalgae Skeletonema costatum Available in Bangladesh Coast: Consideration as Biodiesel Feedstock

    Directory of Open Access Journals (Sweden)

    Tania Sharmin

    2016-01-01

    Full Text Available Among the various potential sources of renewable energy, biofuels are of most interest. Marine microalgae are the most promising oil sources for making biofuels, which can grow very rapidly and convert solar energy to chemical energy via CO2 fixation. The fatty acid profile of almost all the microalgal oil is suitable for the synthesis of biofuel. In this research, fatty acid and lipid contents of Bangladeshi strains of marine microalgae Skeletonema costatum were performed. For this, the crude oil was extracted by Soxhlet extraction method, using three most common solvent systems, pure hexane and mixture of CHCl3 : MeOH (2 : 1 and hexane : EtOH (3 : 1 one by one. Highest oil recovery (15.37% came from CHCl3 : MeOH (2 : 1 solvent system from dry biomass whereas the lowest (2.49% came from n-hexane from wet biomass. The qualitative analysis of the extracted oil by GC/MS analysis revealed that it contained significant amount of myristic acid (C14:0, palmitic acid (C16:0, stearic acid (C18:0, and palmitoleic acid (C16:1. It also indicated presence of hexadecatrienoic acid, benzenedicarboxylic acid, oleic acid, arachidonic acid, eicosapentaenoic acid (EPA, 9-Octadecenoic acid methyl ester (C19H36O2, and so forth. The obtained fatty acid profile indicates high potentiality of S. costatum species to be used as promising biofuel feedstock a little improvisation and substantially it can replace diesel in near future.

  9. Atmospheric PAHs, NPAHs, and OPAHs at an urban, mountainous, and marine sites in Northern China: Molecular composition, sources, and ageing

    Science.gov (United States)

    Zhang, Junmei; Yang, Lingxiao; Mellouki, Abdelwahid; Chen, Jianmin; Chen, Xiangfeng; Gao, Ying; Jiang, Pan; Li, Yanyan; Yu, Hao; Wang, Wenxing

    2018-01-01

    18 gaseous and particulate polycyclic aromatic hydrocarbons (PAHs), 16 nitro-derivative (NPAHs), and 7 oxy-derivative (OPAHs) were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) at three locations in Northern China, an urban site (Jinan), a marine site (Tuoji island), and a mountain site (Mt. Tai). The combined gas and particulate concentrations of 18 PAHs, 16 NPAHs, and 7 OPAHs were highest at the urban site (305.91, 2.80, and 9.05 ng/m3, respectively) and lowest at the mountain location (37.83, 0.27, and 1.59 ng/m3, respectively). A noticeable increase in the high molecular weight PAHs was observed during polluted conditions compared to clean conditions. Diagnostic ratios clearly demonstrated that coal/biomass combustion was the major PAH source in Northern China. The particulate PAHs were the most aged at the mountain site due to long-distance atmospheric transport. The formation rate of NPAHs was most efficient at the mountain location and during heavily polluted days at the urban and marine sites. In addition, the main formation pathway for NPAHs was through the OH initiated secondary reaction. NO3 radicals most significantly contributed to the NPAHs formation at night, during clear weather, and at the mountain site. The logKp value was lowest at the urban site for most individual compounds and highest at the mountain site. Higher logKp was found for NPAHs and OPAHs compared with their corresponding parent PAHs. The linear regression of logKp vs logPL0 at the three sites suggested that the gas-particle partitioning of PAHs might be in non-equilibrium.

  10. Green energy from marine algae: biogas production and composition from the anaerobic digestion of Irish seaweed species.

    Science.gov (United States)

    Vanegas, C H; Bartlett, J

    2013-01-01

    Marine algae have emerged as an alternative feedstock for the production of a number of renewable fuels, including biogas. In addition to energy potential, other characteristics make them attractive as an energy source, including their ability to absorb carbon dioxide (CO2), higher productivity rates than land-based crops and the lack of water use or land competition. For Ireland, biofuels from marine algae can play an important role by reducing imports of fossil fuels as well as providing the necessary energy in rural communities. In this study, five potential seaweed species common in Irish waters, Saccorhiza polyschides, Ulva sp., Laminaria digitata, Fucus serratus and Saccharina latissima, were co-digested individually with bovine slurry. Batch reactors of 120ml and 1000ml were set up and incubated at 35 degrees C to investigate their suitability for production of biogas. Digesters fed with S. latissima produced the maximum methane yield (335 ml g volatile solids(-1) (g(VS)(-1) followed by S. polyschides with 255 ml g(VS)(-1). L. digitata produced 246ml g(VS)(-1) and the lowest yields were from the green seaweed Ulva sp. 191ml g(VS)(-1). The methane and CO2 percentages ranged between 50-72% and 10-45%, respectively. The results demonstrated that the seaweed species investigated are good feedstocks candidates for the production of biogas and methane as a source of energy. Their use on a large-scale process will require further investigation to increase yields and reduce production costs.

  11. Analysis of Aerodynamic Load of LSU-03 (LAPAN Surveillance UAV-03) Propeller

    Science.gov (United States)

    Rahmadi Nuranto, Awang; Jamaludin Fitroh, Ahmad; Syamsudin, Hendri

    2018-04-01

    The existing propeller of the LSU-03 aircraft is made of wood. To improve structural strength and obtain better mechanical properties, the propeller will be redesigned usingcomposite materials. It is necessary to simulate and analyze the design load. This research paper explainsthe simulation and analysis of aerodynamic load prior to structural design phase of composite propeller. Aerodynamic load calculations are performed using both the Blade Element Theory(BET) and the Computational Fluid Dynamic (CFD)simulation. The result of both methods show a close agreement, the different thrust forces is only 1.2 and 4.1% for two type mesh. Thus the distribution of aerodynamic loads along the surface of the propeller blades of the 3-D CFD simulation results are considered valid and ready to design the composite structure. TheCFD results is directly imported to the structure model using the Direct Import CFD / One-Way Fluid Structure Interaction (FSI) method. Design load of propeller is chosen at the flight condition at speed of 20 km/h at 7000 rpm.

  12. The chromium isotopic composition of an Early to Middle Ordovician marine carbonate platform, eastern Precordillera, San Juan, Argentina

    DEFF Research Database (Denmark)

    D'Arcy, Joan Mary; Frei, Robert; Gilleaudeau, Geoffrey Jon

    A broad suite of redox proxy data suggest that despite ocean and atmosphere oxygenation in the late Neoproterozoic, euxinic conditions persisted in the global deep oceans until the at least Ordovician [1,2,3]. Major changes in the sulphur isotopic composition of carbonate associated sulphate and ...

  13. 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...

  14. 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.

  15. 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...

  16. The PROPEL Electrodynamic Tether Demonstration Mission

    Science.gov (United States)

    Bilen, Sven G.; Johnson, C. Les; Wiegmann, Bruce M.; Alexander, Leslie; Gilchrist, Brian E.; Hoyt, Robert P.; Elder, Craig H.; Fuhrhop, Keith P.; Scadera, Michael

    2012-01-01

    The PROPEL ("Propulsion using Electrodynamics") mission will demonstrate the operation of an electrodynamic tether propulsion system in low Earth orbit and advance its technology readiness level for multiple applications. The PROPEL mission has two primary objectives: first, to demonstrate the capability of electrodynamic tether technology to provide robust and safe, near-propellantless propulsion for orbit-raising, de-orbit, plane change, and station keeping, as well as to perform orbital power harvesting and formation flight; and, second, to fully characterize and validate the performance of an integrated electrodynamic tether propulsion system, qualifying it for infusion into future multiple satellite platforms and missions with minimal modification. This paper provides an overview of the PROPEL system and design reference missions; mission goals and required measurements; and ongoing PROPEL mission design efforts.

  17. 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...

  18. Nuclear thermal rockets using indigenous Martian propellants

    International Nuclear Information System (INIS)

    Zubrin, R.M.

    1989-01-01

    This paper considers a novel concept for a Martian descent and ascent vehicle, called NIMF (for nuclear rocket using indigenous Martian fuel), the propulsion for which will be provided by a nuclear thermal reactor which will heat an indigenous Martian propellant gas to form a high-thrust rocket exhaust. The performance of each of the candidate Martian propellants, which include CO2, H2O, CH4, N2, CO, and Ar, is assessed, and the methods of propellant acquisition are examined. Attention is also given to the issues of chemical compatibility between candidate propellants and reactor fuel and cladding materials, and the potential of winged Mars supersonic aircraft driven by this type of engine. It is shown that, by utilizing the nuclear landing craft in combination with a hydrogen-fueled nuclear thermal interplanetary vehicle and a heavy lift booster, it is possible to achieve a manned Mars mission in one launch. 6 refs

  19. Propeller performance analysis using lifting line theory

    OpenAIRE

    Flood, Kevin M.

    2009-01-01

    CIVINS (Civilian Institutions) Thesis document Approved for public release ; distribution is unlimited Propellers are typically optimized to provide the maximum thrust for the minimum torque at a specific number of revolutions per minute (RPM) at a particular ship speed. This process allows ships to efficiently travel at their design speed. However, it is useful to know how the propeller performs during off-design conditions. This is especially true for naval warships whose missions req...

  20. Propellant selection for ramjets with solid fuel

    Energy Technology Data Exchange (ETDEWEB)

    Schmucker, R H; Lips, H

    1976-03-11

    Ramjet propulsion using solid propellant for post-boost acceleration of missiles exhibits several favorable properties, brought about by heterogeneous combustion. A simplified theory for calculating the performance of possible propellants is presented, and they are classified with respect to maximum fuel-specific impulse. The optimal choice of fuel, from a system standpoint, must consider volume constraints, and defines the requirements for motor geometry.

  1. Seasonal variations in the nitrogen isotope composition of Okinotori coral in the tropical western Pacific: A new proxy for marine nitrate dynamics

    Science.gov (United States)

    Yamazaki, Atsuko; Watanabe, Tsuyoshi; Ogawa, Nanako O.; Ohkouchi, Naohiko; Shirai, Kotaro; Toratani, Mitsuhiro; Uematsu, Mitsuo

    2011-12-01

    To demonstrate the utility of coral skeletons as a recorder of nitrate dynamics in the surface ocean, we collected coral skeletons of Porites lobata and determined their nitrogen isotope composition (δ15Ncoral) from 2002 to 2006. Skeletons were collected at Okinotori Island in southwestern Japan, far from any sources of terrestrial nitrogen. Nitrogen isotope compositions along the growth direction were determined at 800 μm intervals (˜1 month resolution) and compared against the skeletal carbon isotope composition (δ13Ccoral-carb), barium/calcium ratio (Ba/Ca), and Chlorophyll-a concentration (Chl-a). From 2002 to 2004, ratios of the δ15Ncoral varied between +0.8 and +8.3‰ with inverse variation to SST (r = -0.53). Ba/Ca ratios and Chl-a concentrations were also observed to be high during seasons with low SST. These results suggested that the vertical mixing that occurs during periods of low SST carries nutrients from deeper water (δ15NDIN; +5˜+6‰) to the sea surface. In 2005 onward, δ15Ncoral and Ba/Ca ratios also had positive peaks even in high SST during periods of transient upwelling caused by frequent large typhoons (maximum wind speed 30 m/s). In addition, low δ15Ncoral (+0.8˜+2.0‰) four months after the last typhoon implied nitrogen fixation because of the lack of typhoon upwelling through the four years record of δ15Ncoral. Variations in the δ13Ccoral-carb and δ15Ncoral were synchronized, suggesting that nitrate concentration could control zooxanthellae photosynthesis. Our results suggested that δ15Ncoral holds promise as a proxy for reconstructing the transport dynamics of marine nitrate and thus also a tool for estimating nitrate origins in the tropical and subtropical oceans.

  2. HMX based enhanced energy LOVA gun propellant

    Energy Technology Data Exchange (ETDEWEB)

    Sanghavi, R.R. [High Energy Materials Research Laboratory, Pune 411021 (India)]. E-mail: sanghavirr@yahoo.co.uk; Kamale, P.J. [High Energy Materials Research Laboratory, Pune 411021 (India); Shaikh, M.A.R. [High Energy Materials Research Laboratory, Pune 411021 (India); Shelar, S.D. [High Energy Materials Research Laboratory, Pune 411021 (India); Kumar, K. Sunil [High Energy Materials Research Laboratory, Pune 411021 (India); Singh, Amarjit [High Energy Materials Research Laboratory, Pune 411021 (India)

    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 deg. 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 {mu}m HMX. Since no work has been reported in open literature regarding replacement of RDX by HMX, the present studies were carried out.

  3. Propeller installation effects on turboprop aircraft acoustics

    Science.gov (United States)

    Chirico, Giulia; Barakos, George N.; Bown, Nicholas

    2018-06-01

    Propeller installation options for a twin-engined turboprop aircraft are evaluated at cruise conditions, aiming to identify the quieter configuration. Computational fluid dynamics is used to investigate the near-field acoustics and transfer functions are employed to estimate the interior cabin noise. Co-rotating and counter-rotating installation options are compared. The effect of propeller synchrophasing is also considered. The employed method captures the complexity of the acoustic field generated by the interactions of the propeller sound fields among each other and with the airframe, showing also the importance of simulating the whole problem to predict the actual noise on a flying aircraft. Marked differences among the various layouts are observed. The counter-rotating top-in option appears the best in terms of acoustics, the top-out propeller rotation leading to louder noise because of inflow conditions and the occurrence of constructive acoustic interferences. Synchrophasing is shown to be beneficial for co-rotating propellers, specially regarding the interior noise, because of favorable effects in the interaction between the propeller direct sound field and the noise due to the airframe. An angle closer to the maximum relative blade shift was found to be the best choice, yielding, however, higher sound levels than those provided by the counter-rotating top-in layout.

  4. A dataset on the species composition of amphipods (Crustacea) in a Mexican marine national park: Alacranes Reef, Yucatan.

    Science.gov (United States)

    Paz-Ríos, Carlos E; Simões, Nuno; Pech, Daniel

    2018-01-01

    Alacranes Reef was declared as a National Marine Park in 1994. Since then, many efforts have been made to inventory its biodiversity. However, groups such as amphipods have been underestimated or not considered when benthic invertebrates were inventoried. Here we present a dataset that contributes to the knowledge of benthic amphipods (Crustacea, Peracarida) from the inner lagoon habitats from the Alacranes Reef National Park, the largest coral reef ecosystem in the Gulf of Mexico. The dataset contains information on records collected from 2009 to 2011. Data are available through Global Biodiversity Information Facility (GBIF). A total of 110 amphipod species distributed in 93 nominal species and 17 generic species, belonging to 71 genera, 33 families and three suborders are presented here. This information represents the first online dataset of amphipods from the Alacranes Reef National Park. The biological material is currently deposited in the crustacean collection from the regional unit of the National Autonomous University of Mexico located at Sisal, Yucatan, Mexico (UAS-Sisal). The biological material includes 588 data records with a total abundance of 6,551 organisms. The species inventory represents, until now, the richest fauna of benthic amphipods registered from any discrete coral reef ecosystem in Mexico.

  5. [Composition of marine sediment samples in the Costa Rica intertidal zones using X-Ray fluorescence analysis].

    Science.gov (United States)

    Salazar, Alfonso; Lizano, Omar G; Alfaro, Eric J

    2004-12-01

    Using an energy dispersive X-Ray fluorescence analysis, simultaneous evaluation of K, Ca, Ti, Cr, Mn, Ge, Ni, Cu, Zn, Br, Rb, Sr and Pb in 74 marine sediment samples from the Costa Rica intertidal zones was conducted. Samples were collected between June 1999 and December 2001, from Caribbean and Pacific beaches of Costa Rica. Calcium and iron showed the highest abundances and are indicators of the natural origin of the sediments. Calcium is associated with biogenic processes such as coral reefs near the sampling sites and iron indicates a terrigenous origin. In general, the beaches of the Caribbean and North Pacific regions showed the greatest concentration of calcium. This is indicative of the abundant reef structures near these beaches. The beaches of the Central and South Pacific show the greatest iron concentrations, indicating an important lithosphere contribution and/or little contribution of calcium carbonate due to the poor development of coralline structures near the sampling sites. Finally, the analyses did not show evidence of elements associated with anthropogenic pollution. Only a northern section of Puerto Viejo beach showed high concentrations of lead, zinc and titanium, perhaps associated with hydrothermal sources.

  6. Influence of culture conditions and medium composition on the production of antibacterial compounds by marine Serratia sp. WPRA3.

    Science.gov (United States)

    Jafarzade, Mahtab; Yahya, Nur Ain; Shayesteh, Fatemeh; Usup, Gires; Ahmad, Asmat

    2013-06-01

    This study was undertaken to investigate the influence of culture conditions and medium components on production of antibacterial compounds by Serratia sp. WPRA3 (JX020764) which was isolated from marine water of Port Dickson, Malaysia. Biochemical, morphological, and molecular characteristics suggested that the isolate is a new candidate of the Serratia sp. The isolate showed strong antimicrobial activity against fungi, Gram-negative and Gram-positive bacteria. This bacterium exhibited optimum antibacterial compounds production at 28°C, pH 7 and 200 rev/min aeration during 72 h of incubation period. Highest antibacterial activity was obtained when sodium chloride (2%), yeast extract (0.5%), and glucose concentration (0.75%) were used as salt, nitrogen, and carbon sources respectively. Different active fractions were obtained by Thin-Layer Chromatography (TLC) and Flash Column Chromatography (FCC) from ethyl acetate crude extracts namely OCE and RCE in different culture conditions, OCE (pH 5, 200 rev/min) and RCE (pH 7/without aeration). In conclusion, the results suggested different culture conditions have a significant impact on the types of secondary metabolites produced by the bacterium.

  7. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2014-01-01

    Cue Rondo is an open composition to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound/video files will in some cases only provide a few minutes' sample, or the visuals will not appear at all....... Please DOWNLOAD them to see/hear them in full length! This work is licensed under a Creative Commons "by-nc" License. You may for non-commercial purposes use and distribute it, performance instructions as well as specially designated recordings, as long as the author is mentioned. Please see http...

  8. Characteristics of a non-volatile liquid propellant in liquid-fed ablative pulsed plasma thrusters

    Science.gov (United States)

    Ling, William Yeong Liang; Schönherr, Tony; Koizumi, Hiroyuki

    2017-02-01

    In the past several decades, the use of electric propulsion in spacecraft has experienced tremendous growth. With the increasing adoption of small satellites in the kilogram range, suitable propulsion systems will be necessary in the near future. Pulsed plasma thrusters (PPTs) were the first form of electric propulsion to be deployed in orbit, and are highly suitable for small satellites due to their inherent simplicity. However, their lifetime is limited by disadvantages such as carbon deposition leading to thruster failure, and complicated feeding systems required due to the conventional use of solid propellants (usually polytetrafluoroethylene (PTFE)). A promising alternative to solid propellants has recently emerged in the form of non-volatile liquids that are stable in vacuum. This study presents a broad comparison of the non-volatile liquid perfluoropolyether (PFPE) and solid PTFE as propellants on a PPT with a common design base. We show that liquid PFPE can be successfully used as a propellant, and exhibits similar plasma discharge properties to conventional solid PTFE, but with a mass bit that is an order of magnitude higher for an identical ablation area. We also demonstrate that the liquid PFPE propellant has exceptional resistance to carbon deposition, completely negating one of the major causes of thruster failure, while solid PTFE exhibited considerable carbon build-up. Energy dispersive X-ray spectroscopy was used to examine the elemental compositions of the surface deposition on the electrodes and the ablation area of the propellant (or PFPE encapsulator). The results show that based on its physical characteristics and behavior, non-volatile liquid PFPE is an extremely promising propellant for use in PPTs, with an extensive scope available for future research and development.

  9. 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

  10. Kinematic matrix theory and universalities in self-propellers and active swimmers.

    Science.gov (United States)

    Nourhani, Amir; Lammert, Paul E; Borhan, Ali; Crespi, Vincent H

    2014-06-01

    We describe an efficient and parsimonious matrix-based theory for studying the ensemble behavior of self-propellers and active swimmers, such as nanomotors or motile bacteria, that are typically studied by differential-equation-based Langevin or Fokker-Planck formalisms. The kinematic effects for elementary processes of motion are incorporated into a matrix, called the "kinematrix," from which we immediately obtain correlators and the mean and variance of angular and position variables (and thus effective diffusivity) by simple matrix algebra. The kinematrix formalism enables us recast the behaviors of a diverse range of self-propellers into a unified form, revealing universalities in their ensemble behavior in terms of new emergent time scales. Active fluctuations and hydrodynamic interactions can be expressed as an additive composition of separate self-propellers.

  11. 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.

  12. Composite Phymatoderma from Neogene deep-marine deposits in Japan: Implications for Phanerozoic benthic interactions between burrows and the trace-makers of Chondrites and Phycosiphon

    Directory of Open Access Journals (Sweden)

    Kentaro Izumi

    2015-12-01

    Full Text Available Among composite trace fossils, one of the most common structures throughout the Phanerozoic are structures (e.g., dwelling trace, feeding trace reworked by Chondrites and/or Phycosiphon. However, differences in the nature of the reworking behaviors of these two ichnogenera remain unknown. Thus, in this study, composite Phymatoderma specimens from the Neogene deep-marine Shiramazu Formation in Japan, particularly those reworked by Chondrites and Phycosiphon, were analyzed to reveal the specific conditions that might control the activities of these trace-makers. Phymatoderma reworked by Phycosiphon is significantly larger than non-reworked Phymatoderma, whereas Phymatoderma reworked by Chondrites shows no significant difference in burrow diameter compared with non-reworked Phymatoderma. The recognized size selectivity (i.e., preference for larger burrows by the Phycosiphon trace-maker can be explained by considering the different feeding strategies of these two ichnogenera; namely deposit-feeding Phycosiphon-makers, which must have processed a significant mass of sediment to obtain sufficient organic matter, whereas chemosymbiotic Chondrites-producers did not require a lot of sediment to obtain nutrients. In order to test these interpretations, a dataset of Phanerozoic trace fossils reworked by Chondrites/Phycosiphon were compiled. Consequently, the Phycosiphon-producers’ preference toward relatively larger burrows was recognized, quantitatively supporting the results of this study. The compilation also indicates that the burrow size might have become one of the important limiting factors for the Phycosiphon-producers that tried to rework the sediments within previous subsurface burrows, at least for 80 million years.

  13. Influence of different propellant systems on ablation of EPDM insulators in overload state

    Science.gov (United States)

    Guan, Yiwen; Li, Jiang; Liu, Yang; Xu, Tuanwei

    2018-04-01

    This study examines the propellants used in full-scale solid rocket motors (SRM) and investigates how insulator ablation is affected by two propellant formulations (A and B) during flight overload conditions. An experimental study, theoretical analysis, and numerical simulations were performed to discover the intrinsic causes of insulator ablation rates from the perspective of lab-scaled ground-firing tests, the decoupling of thermochemical ablation, and particle erosion. In addition, the difference in propellant composition, and the insulator charring layer microstructure were analyzed. Results reveal that the degree of insulator ablation is positively correlated with the propellant burn rate, particle velocity, and aggregate concentrations during the condensed phase. A lower ratio of energetic additive material in the AP oxidizer of the propellant is promising for the reduction in particle size and increase in the burn rate and pressure index. However, the overall higher velocity of a two-phase flow causes severe erosion of the insulation material. While the higher ratio of energetic additive to the AP oxidizer imparts a smaller ablation rate to the insulator (under lab-scale test conditions), the slag deposition problem in the combustion chamber may cause catastrophic consequences for future large full-scale SRM flight experiments.

  14. Research on the combustion properties of propellants with low content of nano metal powders

    Energy Technology Data Exchange (ETDEWEB)

    Zhi, Jiang; Shu-Fen, Li [Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Feng-Qi, Zhao; Zi-Ru, Liu; Cui-Mei, Yin; Yang, Luo; Shang-Wen, Li [Xi' an Modern Chemistry Research Inst., Xi' an 710065 (China)

    2006-04-15

    A comparison of various experimental results for combustionrelated properties evaluation, including burning rates, deflagration heat, flame structures and thermal decomposition properties, of AP/RDX/Al/HTPB composite propellants containing nano metal powders is presented. The thermal behavior of n-Al (nano grain size aluminum) and g-Al (general grain size aluminum i.e., 10 {mu}m) heated in air was also investigated by thermogravimetry. The burning rates results indicate that the usage of bimodal aluminum distribution with the ratio around 4: 1 of n-Al to g-Al or the addition of 2% nano nickel powders (n-Ni) will improve the burning behavior of the propellant, while the usage of grading aluminum powders with the ratio 1: 1 of n-Al to g-Al will impair the combustion of the propellant. Results show that n-Al and n-Ni both have a lower heating capacity, lower ignition threshold and shorter combustion time than g-Al. In addition n-Al is inclined to burn in single particle form. And the thermal analysis results show that n-Ni can catalyze the thermal decomposition of AP in the propellant. The results also confirm the high reactivity of n-Al, which will lead to a lower reaction temperature and rather higher degree of reaction ratio as compared with g-Al in air. All these factors will influence the combustion of propellants. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  15. 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.

  16. 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.

  17. Heterogeneous propellant internal ballistics: criticism and regeneration

    Science.gov (United States)

    Glick, R. L.

    2011-10-01

    Although heterogeneous propellant and its innately nondeterministic, chemically discrete morphology dominates applications, ballisticcharacterization deterministic time-mean burning rate and acoustic admittance measures' absence of explicit, nondeterministic information requires homogeneous propellant with a smooth, uniformly regressing burning surface: inadequate boundary conditions for heterogeneous propellant grained applications. The past age overcame this dichotomy with one-dimensional (1D) models and empirical knowledge from numerous, adequately supported motor developments and supplementary experiments. However, current cost and risk constraints inhibit this approach. Moreover, its fundamental science approach is more sensitive to incomplete boundary condition information (garbage-in still equals garbage-out) and more is expected. This work critiques this situation and sketches a path forward based on enhanced ballistic and motor characterizations in the workplace and approximate model and apparatus developments mentored by CSAR DNS capabilities (or equivalent).

  18. Marine ecology

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Studies on marine ecology included marine pollution; distribution patterns of Pu and Am in the marine waters, sediments, and organisms of Bikini Atoll and the influence of physical, chemical, and biological factors on their movements through marine biogeochemical systems; transfer and dispersion of organic pollutants from an oil refinery through coastal waters; transfer of particulate pollutants, including sediments dispersed during construction of offshore power plants; and raft culture of the mangrove oysters

  19. Design Method for Contra-Rotating Propellers for High-Speed Crafts: Revising the Original Lerbs Theory in a Modern Perspective

    Directory of Open Access Journals (Sweden)

    Stefano Brizzolara

    2012-01-01

    Full Text Available The main theoretical and numerical aspects of a design method for optimum contrar-rotating (CR propellers for fast marine crafts are presented. We propose a reformulated version of a well-known design theory for contra-rotating propellers, by taking advantage of a new fully numerical algorithm for the calculation of the mutually induced velocities and introducing new features such as numerical lifting surface corrections, use of an integrated modern cavitation/strength criteria, a modified method to consider different numbers of blades among the two propellers, and to allow for an unloading function in the search for the optimal circulation distribution. The paper first introduces the main theoretical principles of the new methods and then discusses the influence of the main design parameters on an emblematic example of application in the case of counter rotating propellers for a pod propulsor designed for fast planing crafts (35 knots and above.

  20. Chemical compositions of the marine algae Gracilaria salicornia (Rhodophyta) and Ulva lactuca (Chlorophyta) as a potential food source.

    Science.gov (United States)

    Tabarsa, Mehdi; Rezaei, Masoud; Ramezanpour, Zohreh; Waaland, Joseph Robert

    2012-09-01

    The nutritional compositions of two edible red (Gracilaria salicornia) and green (Ulva lactuca) seaweeds were determined to evaluate their possible uses as potential food ingredients. In general, these species contained limited amounts of lipids ranging between 0.99 and 2.00 g 100 g(-1) dry weight) and considerably high amount of minerals, especially in G. salicornia (38.91 g 100 g(-1) d.w.). The crude protein values varied between 9.58 and 10.69 g 100 g(-1) d.w. Amounts for total amino acids were 889.78 ± 22.64 mg g(-1) protein d.w. in G. salicornia and 543.3 ± 15.14 mg g(-1) protein d.w. in U. lactuca. The most abundant fatty acids were C12:0, C16:0, C20:4 ω6 and C22:5 ω3, in addition to C18:1 in G. salicornia. Both seaweed species were balanced sources of ω3 and ω6 fatty acids with a ratio of ω6/ω3 that varied between 1.2 and 1.17. Between the seaweeds investigated, high levels of K (2414.02-11 380.06 mg 100 g(-1) d.w.) were observed and the amounts of Ca, Na and Fe were higher than those reported for land plants. Thus, G. salicornia and U. lactuca may be utilised as value-added products for human nutrition purposes. Copyright © 2012 Society of Chemical Industry.

  1. Marine pollution

    International Nuclear Information System (INIS)

    Albaiges, J.

    1989-01-01

    This book covers the following topics: Transport of marine pollutants; Transformation of pollutants in the marine environment; Biological effects of marine pollutants; Sources and transport of oil pollutants in the Persian Gulf; Trace metals and hydrocarbons in Syrian coastal waters; and Techniques for analysis of trace pollutants

  2. Proximate composition of marine invertebrates from tropical coastal waters, with emphasis on the relationship between nitrogen and protein contents

    Directory of Open Access Journals (Sweden)

    Graciela S Diniz

    2014-05-01

    Full Text Available The chemical profiles of Desmapsamma anchorata, Hymeniacidon heliophila (Porifera, Bunodosoma caissarum, Renilla muelleri (Cnidaria, Aplysia brasiliana, Eledone massyae, Isognomon bicolor (Mollusca, Echinaster brasiliensis, Echinometra lucunter, Holothuria grisea, Lytechinus variegatus (Echinodermata, and Phallusia nigra (Chordata were determined. Hydrosoluble protein was the most abundant class of substances for all species, except for the ascidian Phallusia nigra, in which the carbohydrate content was higher. The percentages of hydrosoluble protein (dry weight, dw varied widely among the invertebrates, ranging from 5.88% (R. muelleri to 47.6% (Eledone massyae of the dw .The carbohydrate content fluctuated from 1.3% (R. muelleri to 18.4% (Aplysia brasiliana of the dw. For most of the species, lipid was the second most abundant class of substances, varying from 2.8% (R. muelleri to 25.3% (Echinaster brasiliensis of the dw. Wide variations were also found for the invertebrates nitrogen content, with the lowest value recorded in the cnidarian R. muelleri (2.02% of the dw and the highest in the molluscan E. massyae (12.7% of the dw. The phosphorus content of the dw varyed from 0.24% (R. muelleri to 1.16% (E. massyae. The amino acid composition varied largely among the species, but for most of the species glycine, arginine, glutamic acid, and aspartic acid were the most abundant amino acids, with histidine and tyrosine among the less abundant amino acids. The actual content of total protein in the samples was calculated by the sum of amino acid residues, establishing dw values that fluctuated from 11.1% (R. muelleri to 66.7% (E. massyae. The proteinaceous nitrogen content was high in all species, with an average value of 97.3% of the total nitrogen. From data of total amino acid residues and total nitrogen, specific nitrogen-to-protein conversion factors were calculated for each species. The nitrogen-to-protein conversion factors ranged from 5.10 to

  3. Process for the leaching of AP from propellant

    Science.gov (United States)

    Shaw, G. C.; Mcintosh, M. J. (Inventor)

    1980-01-01

    A method for the recovery of ammonium perchlorate from waste solid rocket propellant is described wherein shredded particles of the propellant are leached with an aqueous leach solution containing a low concentration of surface active agent while stirring the suspension.

  4. Neural Network Predictions of the 4-Quadrant Wageningen Propeller Series

    National Research Council Canada - National Science Library

    Roddy, Robert F; Hess, David E; Faller, Will

    2006-01-01

    .... This report describes the development of feedforward neural network (FFNN) predictions of four-quadrant thrust and torque behavior for the Wageningen B-Screw Series of propellers and for two Wageningen ducted propeller series...

  5. 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...

  6. 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....

  7. Marine genomics

    DEFF Research Database (Denmark)

    Oliveira Ribeiro, Ângela Maria; Foote, Andrew David; Kupczok, Anne

    2017-01-01

    Marine ecosystems occupy 71% of the surface of our planet, yet we know little about their diversity. Although the inventory of species is continually increasing, as registered by the Census of Marine Life program, only about 10% of the estimated two million marine species are known. This lag......-throughput sequencing approaches have been helping to improve our knowledge of marine biodiversity, from the rich microbial biota that forms the base of the tree of life to a wealth of plant and animal species. In this review, we present an overview of the applications of genomics to the study of marine life, from...

  8. Ionic liquid propellants: future fuels for space propulsion.

    Science.gov (United States)

    Zhang, Qinghua; Shreeve, Jean'ne M

    2013-11-11

    Use of green propellants is a trend for future space propulsion. Hypergolic ionic liquid propellants, which are environmentally-benign while exhibiting energetic performances comparable to hydrazine, have shown great potential to meet the requirements of developing nontoxic high-performance propellant formulations for space propulsion applications. This Concept article presents a review of recent advances in the field of ionic liquid propellants. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The Effect of Propellant Optical Properties on Composite Solid Propellant Combustion

    Science.gov (United States)

    1991-01-01

    10.0 [cal/gJ CpAP . = 1.3 [J/(g K)1 LhrMp =433. [cal/g] CpfTBp = 1.3 [J/(g K)] Using the experimental burning rates, the surface temperatures of the AP...Photo- Flash Lamps." Journatl of the Optical Society of North America, Vol. 37, No. 8. pp. 652-659, 1947. 17. Parry, D.L.. Ph.D. Thesis, The University of...the light emitters in photoflash lamps. In 1947, Brockman 4 made spectroscopic measurements of the light emitted by flash lamps filled with aluminum

  10. Refinement of Propellant Strand Burning Method to Suit Aluminised Composite Rocket Propellant

    Science.gov (United States)

    2014-12-01

    Garry Hale and Raoul A. Pietrobon Weapons and Combat Systems Division Defence Science and Technology Organisation DSTO-TN-1396... Organisation PO Box 1500 Edinburgh South Australia 5111 Australia Telephone: 1300 362 362 Fax: (08) 7389 6567 © Commonwealth of Australia 2015 AR...with a soft brush (dedusting) and the strands were inhibited with paint diluted by water. The paint was a Super Flat acrylic, deep tint base (Line 500

  11. Changing of ballistic parameters from aged gun propellants

    NARCIS (Netherlands)

    Klerk, W.P.C. de; Driel, C.A. van

    2003-01-01

    The various properties of an SB and a DB gun propellant were investigated before and after artificial ageing. It was found that the decrease of nitrocellulose (NC) molecular weight, due to ageing of gun propellants, leads to a decrease of the mechanical integrity of the propellant grains. The effect

  12. Burning properties and mechanical integrity of aged gun propellants

    NARCIS (Netherlands)

    Driel, C.A. van; Klerk, W.P.C. de

    2017-01-01

    Conventional gun propellants exhibit the phenomenon of nitrocellulose (NC) decomposition. Besides an effect on thermal stability of propellants, decomposition of NC has an effect on the mechanical integrity of the propellant grains. Enhanced grain fracture may lead to unacceptable changes of the

  13. 14 CFR 25.907 - Propeller vibration and fatigue.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller vibration and fatigue. 25.907... vibration and fatigue. This section does not apply to fixed-pitch wood propellers of conventional design. (a... propeller to show that failure due to fatigue will be avoided throughout the operational life of the...

  14. 14 CFR 23.907 - Propeller vibration and fatigue.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller vibration and fatigue. 23.907... General § 23.907 Propeller vibration and fatigue. This section does not apply to fixed-pitch wood... evaluation of the propeller to show that failure due to fatigue will be avoided throughout the operational...

  15. Design Procedure of 4-Bladed Propeller

    African Journals Online (AJOL)

    PROF. O. E. OSUAGWU

    2013-09-01

    Sep 1, 2013 ... West African Journal of Industrial and Academic Research Vol.8 No.1 September 2013 ..... Number of blades. 5. Taylor's wake friction (w). The speed of ship (Vs), the number of propeller revolution (n), the blade number (Z) and the blade area ratio.... .... moment of inertia of a blade, the approximate.

  16. Spray and Combustion of Gelled Hypergolic Propellants

    Science.gov (United States)

    2014-10-20

    moisture absorption on the fumed silica surface correlates directly to the ambient humidity , and can reach 12% by weight at an atmospheric humidity of...propellant interface, the liquid at the interface can be heated to the homogeneous vapor nucleation temperature rather than the boiling point. At this

  17. 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

  18. 75 FR 12148 - Airworthiness Directives; Ontic Engineering and Manufacturing, Inc. Propeller Governors, Part...

    Science.gov (United States)

    2010-03-15

    ... propeller pitch by regulating oil pressure to the propeller pitch change mechanism. Changes in governor oil..., the propeller governor cannot control oil pressure to the propeller pitch control mechanism. This... proposing this AD to prevent loss of propeller pitch control, damage to the propeller governor, and internal...

  19. Effect of the Dispersibility of Nano-CuO Catalyst on Heat Releasing of AP/HTPB Propellant

    International Nuclear Information System (INIS)

    Yang, Y.; Yu, X.; Wang, J.; Wang, Y.

    2011-01-01

    Kneading time is adjusted to change the dispersibility of nano-CuO in AP/HTPB (Ammonia Perchlorate/Hydroxyl-Terminated Polybutadiene) composite propellants. Nano-CuO/AP is prepared to serve as the other dispersing method of nano-CuO, named pre dispersing procedure. Several kinds of heat releasing, thermal decomposition by DSC, combustion heat in oxygen environment, and explosion heat in nitrogen environment, are characterized to learn the effect of dispersibility of nano-CuO catalyst on heat releasing of propellants. With pre-dispersing procedures, thermal decomposition temperature of nano-CuO/AP and its propellant are about 25 degree C and 8.6 degree C lower than that of AP simple mixed with nano-CuO and its propellant, respectively. Comparing propellant with simple mixed nano-CuO kneading 3 hours, combustion heat and explosion heat of propellant with nano-CuO/AP increase about 1.4% and 1.7%, respectively. However, because of the breaking of nano-CuO/AP structure during kneading procedure, combustion heat and explosion heat of all the samples are decreased with the increase of kneading time after 3 hours.

  20. Space Transportation Infrastructure Supported By Propellant Depots

    Science.gov (United States)

    Smitherman, David; Woodcock, Gordon

    2012-01-01

    A space transportation infrastructure is described that utilizes propellant depot servicing platforms to support all foreseeable missions in the Earth-Moon vicinity and deep space out to Mars. The infrastructure utilizes current expendable launch vehicle (ELV) systems 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 Low-Earth-Orbit (LEO) Depot and an Earth-Moon Lagrange Point 1 (L1) Depot to support a 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. New vehicle design concepts are presented that can be launched on current 5 meter diameter ELV systems. These new reusable vehicle concepts include a Crew Transfer Vehicle (CTV) for crew transportation between the LEO Depot, L1 Depot and missions beyond L1; a new reusable lunar lander for crew transportation between the L1 Depot and the lunar surface; and Mars orbital Depot are based on International Space Station (ISS) heritage hardware. Data provided includes the number of launches required for each mission utilizing current ELV systems (Delta IV Heavy or equivalent) and the approximate vehicle masses and propellant requirements. Also included is a discussion on affordability with ideas on technologies that could reduce the number of launches required and thoughts on how this infrastructure include competitive bidding for ELV flights and propellant services, developments of new reusable in-space vehicles and development of a multiuse infrastructure that can support many government and commercial missions simultaneously.

  1. Propellant Slosh Force and Mass Measurement

    Directory of Open Access Journals (Sweden)

    Andrew Hunt

    2018-01-01

    Full Text Available We have used electrical capacitance tomography (ECT to instrument a demonstration tank containing kerosene and have successfully demonstrated that ECT can, in real time, (i measure propellant mass to better than 1% of total in a range of gravity fields, (ii image propellant distribution, and (iii accurately track propellant centre of mass (CoM. We have shown that the ability to track CoM enables the determination of slosh forces, and we argue that this will result in disruptive changes in a propellant tank design and use in a spacecraft. Ground testing together with real-time slosh force data will allow an improved tank design to minimize and mitigate slosh forces, while at the same time keeping the tank mass to a minimum. Fully instrumented Smart Tanks will be able to provide force vector inputs to a spacecraft inertial navigation system; this in turn will (i eliminate or reduce navigational errors, (ii reduce wait time for uncertain slosh settling, since actual slosh forces will be known, and (iii simplify slosh control hardware, hence reducing overall mass. ECT may be well suited to space borne liquid measurement applications. Measurements are independent of and unaffected by orientation or levels of g. The electronics and sensor arrays can be low in mass, and critically, the technique does not dissipate heat into the propellant, which makes it intrinsically safe and suitable for cryogenic liquids. Because of the limitations of operating in earth-bound gravity, it has not been possible to check the exact numerical accuracy of the slosh force acting on the vessel. We are therefore in the process of undertaking a further project to (i build a prototype integrated “Smart Tank for Space”, (ii undertake slosh tests in zero or microgravity, (iii develop the system for commercial ground testing, and (iv qualify ECT for use in space.

  2. Marine biology

    International Nuclear Information System (INIS)

    Thurman, H.V.; Webber, H.H.

    1984-01-01

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index

  3. Investigation on utilization of liquid propellant in ballistic range experiments

    Energy Technology Data Exchange (ETDEWEB)

    Saso, Akihiro; Oba, Shinji; Takayama, Kazuyoshi [Tohoku University, Sendai (Japan)

    1999-10-31

    Experiments were conducted in a ballistic range using a HAN (hydroxylammonium nitrate)-based liquid monopropellant, LP1846. In a 25-mm-bore single-stage gun, using bulk-loaded propellant of 10 to 35 g, a muzzle speed up to 1.0 km/s was obtained. Time variations of propellant chamber pressures and in-tube projectile velocity profiles were measured. The liquid propellant combustion was initiated accompanying a delay time which was created due to the pyrolysis of the propellant. In order to obtain reliable ballistic range performance, the method of propellant loading was revealed to be critical. Since the burning rate of the liquid propellant is relatively low, the peak acceleration and the muzzle speed strongly depend on the rupture pressure of a diaphragm that was inserted between the launch tube and the propellant chamber. (author)

  4. Chemical composition - Sustainable aquafeeds for marine finfish: Effects of vegetable oil replacement feeds containing novel microalgal and fungal oils on growth performance of juvenile sablefish

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The concomitant replacement of fish meal and fish oil in carnivorous marine fish feeds by more sustainable terrestrial alternatives is problematic due to the limited...

  5. Assessment of species composition, diversity, and biomass in marine habitats and subhabitats around offshore islets in the main Hawaiian islands, April 2 - September 20, 2007 (NCEI Accession 0042684)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The marine algae, invertebrate and fish communities were surveyed at ten islet or offshore island sites in the Main Hawaiian Islands in the vicinity of Lanai, (Puu...

  6. Lipid composition - Sustainable aquafeeds for marine finfish: Effects of vegetable oil replacement feeds containing novel microalgal and fungal oils on growth performance of juvenile sablefish

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The concomitant replacement of fish meal and fish oil in carnivorous marine fish feeds by more sustainable terrestrial alternatives is problematic due to the limited...

  7. Composite Cryotank Technologies and Demonstration (CCTD)

    Data.gov (United States)

    National Aeronautics and Space Administration — Advance the technologies for composite cryogenic propellant tanks at diameters suitable for future heavy lift vehicles and other in-space applications with a goal of...

  8. 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.)

  9. Mathematical model of marine diesel engine simulator for a new methodology of self propulsion tests

    Energy Technology Data Exchange (ETDEWEB)

    Izzuddin, Nur; Sunarsih,; Priyanto, Agoes [Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)

    2015-05-15

    As a vessel operates in the open seas, a marine diesel engine simulator whose engine rotation is controlled to transmit through propeller shaft is a new methodology for the self propulsion tests to track the fuel saving in a real time. Considering the circumstance, this paper presents the real time of marine diesel engine simulator system to track the real performance of a ship through a computer-simulated model. A mathematical model of marine diesel engine and the propeller are used in the simulation to estimate fuel rate, engine rotating speed, thrust and torque of the propeller thus achieve the target vessel’s speed. The input and output are a real time control system of fuel saving rate and propeller rotating speed representing the marine diesel engine characteristics. The self-propulsion tests in calm waters were conducted using a vessel model to validate the marine diesel engine simulator. The simulator then was used to evaluate the fuel saving by employing a new mathematical model of turbochargers for the marine diesel engine simulator. The control system developed will be beneficial for users as to analyze different condition of vessel’s speed to obtain better characteristics and hence optimize the fuel saving rate.

  10. Laser Initiated Ignition of Liquid Propellant

    Science.gov (United States)

    1991-01-31

    containers held in a water bath of constant temperature 70*C. A larger vessel containing approximately 2ml of propellant was also heated in each experiment and...controller. A stirrer and forced water circulation ensured that all samples were kept at the same temperature. The water wai first heated to the final 5... electrolysed samples. 3 .. .. ....... ......................... volume of 10 ....... . 5 ....... I • . ... .. . .... .. ...... .. . . .. . . ... . .61.8 2 22i

  11. 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.

  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. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high ... or by any means without permission in writing from the copyright holder. ..... Journal of Chemical Engineering Research and Design 82 ... Indian Ocean Marine Science Association Technical.

  14. Marine Biomedicine

    Science.gov (United States)

    Bang, Frederik B.

    1977-01-01

    Describes early scientific research involving marine invertebrate pathologic processes that may have led to new insights into human disease. Discussed are inquiries of Metchnikoff, Loeb, and Cantacuzene (immunolgic responses in sea stars, horseshoe crabs, and marine worms, respectively). Describes current research stemming from these early…

  15. Marine Biology

    Science.gov (United States)

    Dewees, Christopher M.; Hooper, Jon K.

    1976-01-01

    A variety of informational material for a course in marine biology or oceanology at the secondary level is presented. Among the topics discussed are: food webs and pyramids, planktonic blooms, marine life, plankton nets, food chains, phytoplankton, zooplankton, larval plankton and filter feeders. (BT)

  16. Chemistry of marine sediments

    International Nuclear Information System (INIS)

    Yen, T.F.

    1977-01-01

    Some topics considered are as follows: characterization of sediments in the vicinity of offshore petroleum production; thermal alteration experiments on organic matter in recent marine sediments as a model for petroleum genesis; composition of polluted bottom sediments in Great Lakes harbors; distribution of heavy metals in sediment fractions; recent deposition of lead off the coast of southern California; release of trace constituents from sediments resuspended during dredging operations; and migration of chemical constituents in sediment-seawater interfaces

  17. Development of HAN-based Liquid Propellant Thruster

    Science.gov (United States)

    Hisatsune, K.; Izumi, J.; Tsutaya, H.; Furukawa, K.

    2004-10-01

    Many of propellants that are applied to the conventional spacecraft propulsion system are toxic propellants. Because of its toxicity, considering the environmental pollution or safety on handling, it will be necessary to apply the "green" propellant to the spacecraft propulsion system. The purpose of this study is to apply HAN based liquid propellant (LP1846) to mono propellant thruster. Compared to the hydrazine that is used in conventional mono propellant thruster, HAN based propellant is not only lower toxic but also can obtain higher specific impulse. Moreover, HAN based propellant can be decomposed by the catalyst. It means there are the possibility of applying to the mono propellant thruster that can leads to the high reliability of the propulsion system.[1],[2] However, there are two technical subjects, to apply HAN based propellant to the mono propellant thruster. One is the high combustion temperature. The catalyst will be damaged under high temperature condition. The other is the low catalytic activity. It is the serious problem on application of HAN based propellant to the mono propellant thruster that is used for attitude control of spacecraft. To improve the catalytic activity of HAN based propellant, it is necessary to screen the best catalyst for HAN based propellant. The adsorption analysis is conducted by Monte Carlo Simulation to screen the catalyst metal for HAN and TEAN. The result of analysis shows the Iridium is the best catalyst metal for HAN and TEAN. Iridium is the catalyst metal that is used at conventional mono propellant thruster catalyst Shell405. Then, to confirm the result of analysis, the reaction test about catalyst is conducted. The result of this test is the same as the result of adsorption analysis. That means the adsorption analysis is effective in screening the catalyst metal. At the evaluating test, the various types of carrier of catalyst are also compared to Shell 405 to improve catalytic activity. The test result shows the

  18. Marine litter in an EBSA (Ecologically or Biologically Significant Area) of the central Mediterranean Sea: Abundance, composition, impact on benthic species and basis for monitoring entanglement.

    Science.gov (United States)

    Consoli, Pierpaolo; Andaloro, Franco; Altobelli, Chiara; Battaglia, Pietro; Campagnuolo, Silvana; Canese, Simonepietro; Castriota, Luca; Cillari, Tiziana; Falautano, Manuela; Pedà, Cristina; Perzia, Patrizia; Sinopoli, Mauro; Vivona, Pietro; Scotti, Gianfranco; Esposito, Valentina; Galgani, Francois; Romeo, Teresa

    2018-05-01

    Marine litter is commonly observed everywhere in the ocean. In this study, we analyzed 17 km of video footage, collected by a Remotely Operated Vehicle (ROV) at depths ranging between 20 and 220 m, during 19 transects performed on the rocky banks of the Straits of Sicily. Recently, the Contracting Parties of the Convention on Biological Diversity (CBD) recognized this site as an Ecologically or Biologically Significant Area (EBSA). The research aim was to quantify the abundance of marine litter and its impact on benthic fauna. Litter density ranged from 0 items/100 m 2 to 14.02 items/100 m 2 with a mean (±standard error) of 2.13 (±0.84) items/100 m 2 . The observed average density was higher (5.2 items/100 m 2 ) at depths >100 m than at shallower depths (fishing lines contributed to 98.07% of the overall litter density, then representing the dominant source of marine debris. Litter interactions with fauna were frequently observed, with 30% of litter causing "entanglement/coverage" and 15% causing damage to sessile fauna. A total of 16 species showed interaction (entanglement/coverage or damage) with litter items and 12 of these are species of conservation concern according to international directives and agreements (CITES, Berne Convention, Habitat Directive, SPA/BD Protocol, IUCN Red List); we also observed 7 priority habitats of the SPA/BD Protocol. This research will support the implementation of monitoring "Harm" as recommended by the UN Environment/MAP Regional Plan on Marine Litter Management in the Mediterranean, and the Marine Strategy Framework Directive (MSFD). The institution of a SPAMI in the investigated area could represent a good management action for the protection of this hotspot of biodiversity and to achieve a Good Environmental Status (GES) for the marine environment by 2020, under the MSFD. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Numerical Analysis of Ice Impacts on Azimuth Propeller

    Science.gov (United States)

    2013-09-01

    uniformity as one solid object, though the built-on process is recognized as well. The number of blades for this propeller varies to control cavitation ...Figure 7). The CRP allows the hydrodynamic advantage of regaining lost rotational energy from the first propeller, which is the conventional...it speeds flow through and accelerates it past the propellers. Decelerating duct slows the flow and allows for greatly reduced cavitation and

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

    Science.gov (United States)

    2016-06-01

    2013 - 06/01/2016 A Portable Burn Pan for the Disposal of Excess Propellants Michael Walsh USA CRREL USA CRREL 72 Lyme Road Hanover, NH 03755...Army Alaska XRF X-Ray Florescence vii ACKNOWLEDGEMENTS Project ER-201323, A Portable Burn Pan for the Disposal of Gun Propellants, was a very...contamination problem while allowing troops to train as they fight, we have developed a portable training device for burning excess gun propellants. 1.1

  1. 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

  2. Electric Propellant Solid Rocket Motor Thruster Results Enabling Small Satellites

    OpenAIRE

    Koehler, Frederick; Langhenry, Mark; Summers, Matt; Villarreal, James; Villarreal, Thomas

    2017-01-01

    Raytheon Missile Systems has developed and tested true on/off/restart solid propellant thrusters which are controlled only by electrical current. This new patented class of energetic rocket propellant is safe, controllable and simple. The range of applications for this game changing technology includes attitude control systems and a safe alternative to higher impulse space satellite thrusters. Described herein are descriptions and performance data for several small electric propellant solid r...

  3. OPTIMIZATION OF POTASSIUM NITRATE BASED SOLID PROPELLANT GRAINS FORMULATION USING RESPONSE SURFACE METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Oladipupo Olaosebikan Ogunleye

    2015-08-01

    Full Text Available This study was designed to evaluate the effect of propellant formulation and geometry on the solid propellant grains internal ballistic performance using core, bates, rod and tubular and end-burn geometries. Response Surface Methodology (RSM was used to analyze and optimize the effect of sucrose, potassium nitrate and carbon on the chamber pressure, temperature, thrust and specific impulse of the solid propellant grains through Central Composite Design (CCD of the experiment. An increase in potassium nitrate increased the specific impulse while an increase in sucrose and carbon decreased specific impulse. The coefficient of determination (R2 for models of chamber pressure, temperature, thrust and specific impulse in terms of composition and geometry were 0.9737, 0.9984, 0.9745 and 0.9589, respectively. The optimum specific impulse of 127.89 s, pressure (462201 Pa, temperature (1618.3 K and thrust (834.83 N were obtained using 0.584 kg of sucrose, 1.364 kg of potassium nitrate and 0.052 kg of carbon as well as bate geometry. There was no significant difference between the calculated and experimented ballistic properties at p < 0.05. The bate grain geometry is more efficient for minimizing the oscillatory pressure in the combustion chamber.

  4. Marine Science

    African Journals Online (AJOL)

    between humans and the coastal and marine environment. ... The journal has a new and more modern layout, published online only, and the editorial .... the population structure of Platorchestia fayetta sp. nov. and their interaction with the.

  5. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the ... tidal height and amplitude can influence light penetra- ...... to environmental parameters in cage culture area of Sepanggar Bay, Malaysia.

  6. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ... consist of special issues on major events or important thematic issues. ... of sources, including plant and animal by- products.

  7. Marine biotoxins

    National Research Council Canada - National Science Library

    2004-01-01

    ... (ciguatera fish poisoning). It discusses in detail the causative toxins produced by marine organisms, chemical structures and analytical methods, habitat and occurrence of the toxin-producing organisms, case studies and existing regulations...

  8. Marine Science

    African Journals Online (AJOL)

    pod diversity and distribution are important especially since studies on marine biodiversity are scarce .... Method II –. Zamoum &. Furla (2012) protocol. Method III. – Geist et al (2008) protocol ..... Public Library Of Science One 8: 51273.

  9. Marine pollution

    International Nuclear Information System (INIS)

    Clark, R.B.

    1992-01-01

    The effects of petroleum, waste materials, halogenated hydrocarbons, radioactivity and heat on the marine ecosystem, the fishing industry and human health are discussed using the example of the North Sea. (orig.) [de

  10. Marine Science

    African Journals Online (AJOL)

    No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form ... to optimize nucleic acid extraction protocols from marine gastropods, present an ...... Greenfield., Gomez E, Harvell CD, Sale PF, Edwards.

  11. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high ..... circulation patterns include the nutrient-rich Somali ...... matical Structures in Computer Science 24: e240311.

  12. Marine insects

    National Research Council Canada - National Science Library

    Cheng, Lanna

    1976-01-01

    .... Not only are true insects, such as the Collembola and insect parasites of marine birds and mammals, considered, but also other kinds of intertidal air-breathing arthropods, notably spiders, scorpions...

  13. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue .... shell growth is adversely affected. ... local stressors in action, such as ocean acidification ..... that the distribution of many intertidal sessile animals.

  14. Solid propellant processing factor in rocket motor design

    Science.gov (United States)

    1971-01-01

    The ways are described by which propellant processing is affected by choices made in designing rocket engines. Tradeoff studies, design proof or scaleup studies, and special design features are presented that are required to obtain high product quality, and optimum processing costs. Processing is considered to include the operational steps involved with the lining and preparation of the motor case for the grain; the procurement of propellant raw materials; and propellant mixing, casting or extrusion, curing, machining, and finishing. The design criteria, recommended practices, and propellant formulations are included.

  15. 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...

  16. Aluminum agglomeration involving the second mergence of agglomerates on the solid propellants burning surface: Experiments and modeling

    Science.gov (United States)

    Ao, Wen; Liu, Xin; Rezaiguia, Hichem; Liu, Huan; Wang, Zhixin; Liu, Peijin

    2017-07-01

    The agglomeration of aluminum particles usually occurs on the burning surface of aluminized composite propellants. It leads to low propellant combustion efficiency and high two-phase flow losses. To reach a thorough understanding of aluminum agglomeration behaviors, agglomeration processes, and particles size distribution of Al/AP/RDX/GAP propellants were studied by using a cinephotomicrography experimental technique, under 5 MPa. Accumulation, aggregation, and agglomeration phenomena of aluminum particles have been inspected, as well as the flame asymmetry of burning agglomerates. Results reveals that the dependency of the mean and the maximum agglomeration diameter to the burning rate and the virgin aluminum size have the same trend. A second-time mergence of multiple agglomerates on the burning surface is unveiled. Two typical modes of second mergence are concluded, based upon vertical and level movement of agglomerates, respectively. The latter mode is found to be dominant and sometimes a combination of the two modes may occur. A new model of aluminum agglomeration on the burning surface of composite propellants is derived to predict the particulates size distribution with a low computational amount. The basic idea is inspired from the well-known pocket models. The pocket size of the region formed by adjacent AP particles is obtained through scanning electron microscopy of the propellant cross-section coupled to an image processing method. The second mergence mechanism, as well as the effect of the burning rate on the agglomeration processes, are included in the present model. The mergence of two agglomerates is prescribed to occur only if their separation distance is less than a critical value. The agglomerates size distribution resulting from this original model match reasonably with the experimental data. Moreover, the present model gives superior results for mean agglomeration diameter compared to common empirical and pocket models. The average prediction

  17. Iridium-catalyst-based autonomous bubble-propelled graphene micromotors with ultralow catalyst loading.

    Science.gov (United States)

    Wang, Hong; Sofer, Zdeněk; Eng, Alex Yong Sheng; Pumera, Martin

    2014-11-10

    A novel concept of an iridium-based bubble-propelled Janus-particle-type graphene micromotor with very high surface area and with very low catalyst loading is described. The low loading of Ir catalyst (0.54 at %) allows for fast motion of graphene microparticles with high surface area of 316.2 m(2)  g(-1). The micromotor was prepared with a simple and scalable method by thermal exfoliation of iridium-doped graphite oxide precursor composite in hydrogen atmosphere. Oxygen bubbles generated from the decomposition of hydrogen peroxide at the iridium catalytic sites provide robust propulsion thrust for the graphene micromotor. The high surface area and low iridium catalyst loading of the bubble-propelled graphene motors offer great possibilities for dramatically enhanced cargo delivery. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 75 FR 62333 - Airworthiness Directives; Hamilton Sundstrand Propellers Model 247F Propellers

    Science.gov (United States)

    2010-10-08

    ...., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory... that the 247F propeller blades, P/N 817370-1, S/Ns FR2449 to FR2958 inclusive, FR20010710 to FR20010722 inclusive, and FR20010723RT to FR20020127RT inclusive, manufactured since January 1999, might also have...

  19. 76 FR 25534 - Airworthiness Directives; Hamilton Sundstrand Propellers Model 247F Propellers

    Science.gov (United States)

    2011-05-05

    ... 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the... through FR2279 inclusive, FR 2398, FR2449 to FR2958 inclusive, FR20010710 to FR20010722 inclusive, and FR20010723RT to FR20020127RT inclusive, installed. Propeller blades reworked to Hamilton Sundstrand Service...

  20. 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.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...

  2. PHM Enabled Autonomous Propellant Loading Operations

    Science.gov (United States)

    Walker, Mark; Figueroa, Fernando

    2017-01-01

    The utility of Prognostics and Health Management (PHM) software capability applied to Autonomous Operations (AO) remains an active research area within aerospace applications. The ability to gain insight into which assets and subsystems are functioning properly, along with the derivation of confident predictions concerning future ability, reliability, and availability, are important enablers for making sound mission planning decisions. When coupled with software that fully supports mission planning and execution, an integrated solution can be developed that leverages state assessment and estimation for the purposes of delivering autonomous operations. The authors have been applying this integrated, model-based approach to the autonomous loading of cryogenic spacecraft propellants at Kennedy Space Center.

  3. High Power Flex-Propellant Arcjet Performance

    Science.gov (United States)

    Litchford, Ron J.

    2011-01-01

    A MW-class electrothermal arcjet based on a water-cooled, wall-stabilized, constricted arc discharge configuration was subjected to extensive performance testing using hydrogen and simulated ammonia propellants with the deliberate aim of advancing technology readiness level for potential space propulsion applications. The breadboard design incorporates alternating conductor/insulator wafers to form a discharge barrel enclosure with a 2.5-cm internal bore diameter and an overall length of approximately 1 meter. Swirling propellant flow is introduced into the barrel, and a DC arc discharge mode is established between a backplate tungsten cathode button and a downstream ringanode/ spin-coil assembly. The arc-heated propellant then enters a short mixing plenum and is accelerated through a converging-diverging graphite nozzle. This innovative design configuration differs substantially from conventional arcjet thrusters, in which the throat functions as constrictor and the expansion nozzle serves as the anode, and permits the attainment of an equilibrium sonic throat (EST) condition. During the test program, applied electrical input power was varied between 0.5-1 MW with hydrogen and simulated ammonia flow rates in the range of 4-12 g/s and 15-35 g/s, respectively. The ranges of investigated specific input energy therefore fell between 50-250 MJ/kg for hydrogen and 10-60 MJ/kg for ammonia. In both cases, observed arc efficiencies were between 40-60 percent as determined via a simple heat balance method based on electrical input power and coolant water calorimeter measurements. These experimental results were found to be in excellent agreement with theoretical chemical equilibrium predictions, thereby validating the EST assumption and enabling the utilization of standard TDK nozzle expansion analyses to reliably infer baseline thruster performance characteristics. Inferred specific impulse performance accounting for recombination kinetics during the expansion process

  4. 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...

  5. 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.

  6. Nuclear thermal rockets using indigenous extraterrestrial propellants

    International Nuclear Information System (INIS)

    Zubrin, R.M.

    1990-01-01

    A preliminary examination of a concept for a Mars and outer solar system exploratory vehicle is presented. Propulsion is provided by utilizing a nuclear thermal reactor to heat a propellant volatile indigenous to the destination world to form a high thrust rocket exhaust. Candidate propellants, whose performance, materials compatibility, and ease of acquisition are examined and include carbon dioxide, water, methane, nitrogen, carbon monoxide, and argon. Ballistics and winged supersonic configurations are discussed. It is shown that the use of this method of propulsion potentially offers high payoff to a manned Mars mission. This is accomplished by sharply reducing the initial mission mass required in low earth orbit, and by providing Mars explorers with greatly enhanced mobility in traveling about the planet through the use of a vehicle that can refuel itself each time it lands. Thus, the nuclear landing craft is utilized in combination with a hydrogen-fueled nuclear-thermal interplanetary launch. By utilizing such a system in the outer solar system, a low level aerial reconnaissance of Titan combined with a multiple sample return from nearly every satellite of Saturn can be accomplished in a single launch of a Titan 4 or the Space Transportation System (STS). Similarly a multiple sample return from Callisto, Ganymede, and Europa can also be accomplished in one launch of a Titan 4 or the STS

  7. Composition and structure of managed pine stands compared to reference longleaf pine sites on Marine Corps Base Camp Lejeune, North Carolina

    Science.gov (United States)

    Joan L. Walker; Andrea M. Silletti; Susan Cohen

    2010-01-01

    We sampled the ground layer of 28 pine plantations to compare with ecological reference sites at Marine Corps Base, Camp Lejeune (MCBCL), NC. Plantations were ≥ 18 years old and had been burned within the previous year. Pines had been hand-planted on beds or fl at-planted, and the plantations were burned every 3 to 4 years after age 7. Data from 39 reference sites were...

  8. Collecting marine litter during regular fish surveys

    NARCIS (Netherlands)

    Sluis, van der M.T.; Hal, van R.

    2014-01-01

    This report presents the results of the marine litter monitoring on the IBTS survey of 2014 and the BTS survey of 2013. Since 2013 marine litter is collected during the International Bottom Trawl Survey (IBTS) and Dutch Beam Trawl Survey (BTS) following a protocol developed by ICES. The composition

  9. 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...

  10. 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

  11. 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...

  12. Propellant and Purge System Contamination "2007: A Summer of Fun"

    Science.gov (United States)

    Galloway, Randy

    2010-01-01

    This slide presentation reviews the propellant and purge system contamination that occurred during the summer of 2007 at Stennis Space Center. During this period Multiple propellant/pressurant system contamination events prompted a thorough investigation, the results of which are reviewed.

  13. 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 ...

  14. Fatty acid composition and bacterial community changes in the rumen fluid of lactating sheep fed sunflower oil plus incremental levels of marine algae.

    Science.gov (United States)

    Toral, P G; Belenguer, A; Shingfield, K J; Hervás, G; Toivonen, V; Frutos, P

    2012-02-01

    Supplementation of ruminant diets with plant oils and marine lipids is an effective strategy for lowering saturated fatty acid (FA) content and increasing the concentration of cis-9,trans-11 conjugated linoleic acid and long-chain n-3 FA in ruminant milk. However, changes in populations of ruminal microorganisms associated with altered biohydrogenation of dietary unsaturated FA are not well characterized. Twenty-five lactating Assaf ewes were allocated at random to 1 of 5 treatments composed of dehydrated alfalfa hay and concentrates containing no additional lipid (control), or supplemented with 25 g of sunflower oil and 0 (SO), 8 (SOMA(1)), 16 (SOMA(2)), or 24 (SOMA(3)) g of marine algae/kg of diet dry matter. On d 28 on diet, samples of rumen fluid were collected for lipid analysis and microbial DNA extraction. Appearance and identification of biohydrogenation intermediates was determined based on complementary gas chromatography and Ag+-HPLC analysis of FA methyl esters. Total bacteria and the Butyrivibrio group were studied in microbial DNA by terminal RFLP analysis, and real-time PCR was used to quantify the known Butyrivibrio bacteria that produce trans-11 18:1 or 18:0. Dietary supplements of sunflower oil alone or in combination with marine algae altered the FA profile of rumen fluid, which was associated with changes in populations of specific bacteria. Inclusion of marine algae in diets containing sunflower oil resulted in the accumulation of trans 18:1 and 10-O-18:0 and a marked decrease in 18:0 concentrations in rumen fluid. At the highest levels of supplementation (SOMA(2) and SOMA(3)), marine algae also promoted a shift in ruminal biohydrogenation pathways toward the formation of trans-10 18:1 at the expense of trans-11 18:1. Changes in the concentration of biohydrogenation intermediates were not accompanied by significant variations in the abundance of known cultivated ruminal bacteria capable of hydrogenating unsaturated FA. However, certain

  15. Development of strand burner for solid propellant burning rate studies

    International Nuclear Information System (INIS)

    Aziz, A; Mamat, R; Ali, W K Wan

    2013-01-01

    It is well-known that a strand burner is an apparatus that provides burning rate measurements of a solid propellant at an elevated pressure in order to obtain the burning characteristics of a propellant. This paper describes the facilities developed by author that was used in his studies. The burning rate characteristics of solid propellant have be evaluated over five different chamber pressures ranging from 1 atm to 31 atm using a strand burner. The strand burner has a mounting stand that allows the propellant strand to be mounted vertically. The strand was ignited electrically using hot wire, and the burning time was recorded by electronic timer. Wire technique was used to measure the burning rate. Preliminary results from these techniques are presented. This study shows that the strand burner can be used on propellant strands to obtain accurate low pressure burning rate data

  16. 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.

  17. 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...

  18. Otters, Marine

    Science.gov (United States)

    Estes, James A.; Bodkin, James L.; Ben-David, M.; Perrin, William F.; Würsing, Bernd; Thewissen, J.G.M.

    2009-01-01

    The otters (Mustelidae; Lutrinae) provide an exceptional perspective into the evolution of marine living by mammals. Most extant marine mammals (e.g. the cetaceans, pinnipeds, and sirenians) have been so highly modified by long periods of selection for life in the sea that they bear little resemblance to their terrestrial ancestors. Marine otters, in contrast, are more recent expatriates from freshwater habitats and some species still live in both environments. Contrasts among species within the otters, and among the otters, terrestrial mammals, and the more highly adapted pinnipeds and cetaceans provide powerful insights into mammalian adaptations to life in the sea (Estes, 1989). Among the marine mammals, sea otters (Enhydra lutris, Fig. 1) provide the clearest understanding of consumer-induced effects on ecosystem function. This is due in part to opportunities provided by history and in part to the relative ease with which shallow coastal systems where sea otters live can be observed and studied. Although more difficult to study than sea otters, other otter species reveal the connectivity among the marine, freshwater, and terrestrial systems. These three qualities of the otters – their comparative biology, their role as predators, and their role as agents of ecosystem connectivity – are what make them interesting to marine mammalogy.The following account provides a broad overview of the comparative biology and ecology of the otters, with particular emphasis on those species or populations that live in the sea. Sea otters are features prominently, in part because they live exclusively in the sea whereas other otters have obligate associations with freshwater and terrestrial environments (Kenyon, 1969; Riedman and Estes, 1990).

  19. Marine Battlefields

    DEFF Research Database (Denmark)

    Harðardóttir, Sara

    as they are an important food source for various marine animals. For both phytoand zooplankton predation is a major cause of mortality, and strategies for protection or avoidance are important for survival. Diatoms of the genera Nitzschia and Pseudo-nitzschia are known to produce a neuro-toxin, domoic acid (DA). Despite......Phytoplankton species are photosynthetic organisms found in most aquatic habitats. In the ocean, phytoplankton are tremendously important because they produce the energy that forms the base of the marine food web. Zooplankton feed on phytoplankton and mediate the energy to higher trophic levels...

  20. 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

  1. 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.

  2. Experimental research on air propellers V

    Science.gov (United States)

    Durand, W F; Lesley, E P

    1923-01-01

    In previous reports on experimental research on air propellers, by W. F. Durand and E. P. Lesley, as contained in the National Advisory Committee for Aeronautics reports nos. 14, 30, and 64, the investigations were made progressively and each without reference to results given in preceding reports and covering only information relating to forms perhaps adjacent in geometrical form and proportion. This report is a review of the entire series of results of the preceding reports with a view of examining through graphical and other appropriate means the nature of the history of the characteristics of operation as related to the systematic variations in characteristics of forms, etc., through the series of such characteristics.

  3. 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.

  4. Marine Science

    African Journals Online (AJOL)

    Science. The journal has a new and more modern layout, published online only, and the editorial. Board was increased to include more disciplines pertaining to marine sciences. While important chal- lenges still lie ahead, we are steadily advancing our standard to increase visibility and dissemination throughout the global ...

  5. Marine Mammals.

    Science.gov (United States)

    Meith, Nikki

    Marine mammals have not only fascinated and inspired human beings for thousands of years, but they also support a big business by providing flesh for sea-borne factories, sustaining Arctic lifestyles and traditions, and attracting tourists to ocean aquaria. While they are being harpooned, bludgeoned, shot, netted, and trained to jump through…

  6. Marine Science

    African Journals Online (AJOL)

    Mauritius Marine Conservation Society through their. Abstract. While no populations of seals are resident in the tropical Indian Ocean, vagrant animals are occasionally sighted in the region. Here we detail two new sightings of pinnipeds in the Mascarene Islands (Mauritius, Reunion and Rodri- gues) since 1996 and review ...

  7. Marine Science

    African Journals Online (AJOL)

    J O U R N A L O F. Marine Science. Coral reefs of Mauritius in a changing global climate ..... in confined aquifers, and a lesser influence in uncon- fined systems. On the ... massive cloud cover during the critical months, some. 70% bleaching ...

  8. Marine Science

    African Journals Online (AJOL)

    Copy Editor Timothy Andrew. Published ... 2007; Zhou et al., 2009) and they play an important role in the ... At both sites, zonal variation in TMPB was evident with significantly higher C-biomass closer to ... ton is considered to be an essential parameter in eco- systems ...... logical significance of toxic marine dinoflagellates.

  9. Marine Science

    African Journals Online (AJOL)

    sustainable coastal development in the region, as well as contributing to the ... between humans and the coastal and marine environment. ... exploitation for timber, fuel wood, aquaculture, urban. Abstract. Given the high dependence of coastal communities on natural resources, mangrove conservation is a challenge in.

  10. Marine Science

    African Journals Online (AJOL)

    No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means ... USA/Norway ... The last couple of years have been a time of change for the Western Indian Ocean Journal of Marine.

  11. Marine Science

    African Journals Online (AJOL)

    Chief Editor José Paula | Faculty of Sciences of University of Lisbon, Portugal. Copy Editor Timothy Andrew. Published biannually. Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high quality research generated in the Western Indian Ocean (WIO) ...

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Design study of technology requirements for high performance single-propeller-driven business airplanes

    Science.gov (United States)

    Kohlman, D. L.; Hammer, J.

    1985-01-01

    Developments in aerodyamic, structural and propulsion technologies which influence the potential for significant improvements in performance and fuel efficiency of general aviation business airplanes are discussed. The advancements include such technolgies as natural laminar flow, composite materials, and advanced intermittent combustion engines. The design goal for this parameter design study is a range of 1300 nm at 300 knots true airspeed with a payload of 1200lbs at 35,000 ft cruise altitude. The individual and synergistic effects of various advanced technologies on the optimization of this class of high performance, single engine, propeller driven business airplanes are identified.

  17. Catalytic micromotor generating self-propelled regular motion through random fluctuation

    Science.gov (United States)

    Yamamoto, Daigo; Mukai, Atsushi; Okita, Naoaki; Yoshikawa, Kenichi; Shioi, Akihisa

    2013-07-01

    Most of the current studies on nano/microscale motors to generate regular motion have adapted the strategy to fabricate a composite with different materials. In this paper, we report that a simple object solely made of platinum generates regular motion driven by a catalytic chemical reaction with hydrogen peroxide. Depending on the morphological symmetry of the catalytic particles, a rich variety of random and regular motions are observed. The experimental trend is well reproduced by a simple theoretical model by taking into account of the anisotropic viscous effect on the self-propelled active Brownian fluctuation.

  18. Proximate composition, mineral content and fatty acid profile of two marine fishes from Cameroonian coast: Pseudotolithus typus (Bleeker, 1863 and Pseudotolithus elongatus (Bowdich, 1825

    Directory of Open Access Journals (Sweden)

    J.M. Njinkoue

    2016-10-01

    Full Text Available Background: Knowledge of chemical composition of fish from Cameroon is poor. The genera Pseudotolithus are nutritionally and economically important in Cameroon. Thus the knowledge on their chemical composition could help in functional food elaboration. Purpose: In this study, Proximate composition, fatty acid profiles and mineral composition were determined in two fish species, Pseudotolithus typus and Pseudotolithus elongatus from Cameroonian coasts. Basic procedure: AOAC standard method was used. Fatty acids were identified by GC/MS as N-acylpyrolidides. Mineral compositions were determined by atomic absorption spectrophotometry for Ca, Na, K, Mg, Fe, Zn, Cu, Mn, and by UV spectrophotometry for phosphorus (P. Main finding: Results indicated that chemical composition was not similar in the two fish species. Results also showed that water is the main constituent in the edible parts and in the bones with 76.17% to 78.24% and 51.21% to 55.28% respectively. Pseudotolithus typus and Pseudotolithus elongatus were good sources of proteins with 16.17% and 13.4% respectively. All the fish analyzed for fat were lean with fat contents less than 0.5%. These species of fish were poor in ω6PUFA and were rich in ω3PUFA with about one third of total fatty acids. The main ω3 fatty acids were eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA. The most abundant main elements were the potassium in the edible parts (1.39% and calcium in the bones (18.26%. The most abundant trace elements were Zn and Fe in the edible parts and in the bones. Principal conclusion: The Na/K ratio values and ω3 fatty acids contents suggest that consumption of these two fish species could be recommended to prevent cardiovascular diseases. Keywords: Proximal composition, Mineral content, Fatty acid profiles, Pseudotolithus typus, Pseudotolithus elongates

  19. Prevention of Dealloying in Manganese Aluminium Bronze Propeller: Part II

    Directory of Open Access Journals (Sweden)

    Napachat Tareelap

    2014-03-01

    Full Text Available Due to the failure of manganese aluminium bronze (MAB propeller caused by dealloying corrosion as described in Part I [1], this work aims to study the prevention of dealloying corrosion using aluminium and zinc sacrificial anodes. The results indicated that both of the sacrificial anodes could prevent the propeller from dealloying. Moreover, the dealloying in seawater was less than that found in brackish water. It was possible that hydroxide ions, from cathodic reaction, reacted with calcium in seawater to form calcium carbonate film protecting the propeller from corrosion.

  20. 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.

  1. Analysis of Engine Propeller Matching of DC Motor as a Main Propulsion

    Directory of Open Access Journals (Sweden)

    Eddy Setyo Koenhardono

    2017-12-01

    Full Text Available The development of ship always searches through the most benefits system for reducing costs of propulsion system without increase pollution. Diesel propulsion system or also known as conventional propulsion system is efficient but requires high operating costs and increase high level of marine pollution. Electrical propulsion system is using electric motors as the prime mover of the propeller. There are 2 types of electric motors that will be used for research of electric propulsion system, there are; DC motors and three-phases induction motor. As the use of DC motor as a prime mover for this electrical propulsion system, this study determines the characteristic between voltage terminal with torque and also field current with torque. It results that torque produced by the DC motor is in the same magnitude with the speed (RPM. The higher the speed have shaped the value of the torque. The input and terminal voltages adjusts all variables and results. In this study, different field voltage creates different pattern of motor envelope. Its manner to propeller curve occurs total different results. With field voltage of 50 V, the ranges of motor envelope immoveable in the point of 150% of present speed and 160%. While field voltage of 60 V serves larger ranges of motor envelope which possible to reach further than 50 V curve.

  2. Using the scanning electron microscope and energy dispersive x-ray spectrometer to do mineral identification and compositional point counting on unconsolidated marine sediments

    International Nuclear Information System (INIS)

    Robson, S.H.

    1982-01-01

    This paper describes a rapid and accurate method of point-counting sands and silt-size in unconsolidated open-ocean sediments. As traditional techniques for this operation cannot be employed on the fine-grained material which frequently forms the bulk of deep sea marine sediments, an alternative method has been sought. The method described makes use of equipment known as QUANTEX-RAY comprising a computerised data acquisition and reduction system designed for use in X-ray energy spectrometry and used in conjunction with a scanning electron microscope (SEM). Grains that cannot be identified by their visual morphology in the scanning electron microscope are analysed by X-ray spectrometry. Spectra are acquired in 200 seconds or less and processed by a sequence of software routines under semi-automatic control producing a listing of oxide concentrations as the final result. Each user must customize the control programme and operating conditions to suit his requirements

  3. Neoproterozoic marine carbonates and their paleoceanographic significance

    Science.gov (United States)

    Hood, Ashleigh van Smeerdijk; Wallace, Malcolm William

    2018-01-01

    The primary mineralogy of marine carbonate precipitates has been a crucial factor in constraining the major element composition of ancient oceans. Secular changes in Phanerozoic marine chemistry, including Mg/Ca, have been well-documented using the original carbonate mineralogy of ooids, marine cements and biominerals. However, the history of Precambrian seawater chemistry is not as well constrained, partially due to the prevalence of dolomitisation in the Precambrian geological record. The Neoproterozoic ( 1000 Ma to 541 Ma) record of primary carbonate mineralogy is documented here using a combination of literature data and new analysis of marine carbonate precipitates from the Otavi Fold Belt, Namibia, the Death Valley succession, USA and the Adelaide Fold Belt, Australia. These data suggest that the last 460 million years of the Proterozoic were dominated by aragonite and high-Mg calcite precipitation in shallow marine settings. In contrast, low-Mg calcite has only been recognised in a small number of formations. In addition to aragonite and calcite precipitation, marine dolomite precipitation was widespread in Neoproterozoic oceans, including mimetic (syn-sedimentary) dolomitisation and primary dolomite marine cementation. The combination of marine aragonite, high Mg-calcite and dolomite precipitation during the Neoproterozoic suggests extremely high seawater Mg/Ca conditions relative to Phanerozoic oceans. Marine dolomite precipitation may also be linked to widespread marine anoxia during this time.

  4. Ignition and combustion characteristics of metallized propellants

    Science.gov (United States)

    Turns, Stephen R.; Mueller, D. C.

    1993-01-01

    Experimental and analytical investigations focusing on secondary atomization and ignition characteristics of aluminum/liquid hydrocarbon slurry propellants were conducted. Experimental efforts included the application of a laser-based, two-color, forward-scatter technique to simultaneously measure free-flying slurry droplet diameters and velocities for droplet diameters in the range of 10-200 microns. A multi-diffusion flame burner was used to create a high-temperature environment into which a dilute stream of slurry droplets could be introduced. Narrowband measurements of radiant emission were used to determine if ignition of the aluminum in the slurry droplet had occurred. Models of slurry droplet shell formation were applied to aluminum/liquid hydrocarbon propellants and used to ascertain the effects of solids loading and ultimate particle size on the minimum droplet diameter that will permit secondary atomization. For a 60 weight-percent Al slurry, the limiting critical diameter was predicted to be 34.7 microns which is somewhat greater than the 20-25 micron limiting diameters determined in the experiments. A previously developed model of aluminum ignition in a slurry droplet was applied to the present experiments and found to predict ignition times in reasonable agreement with experimental measurements. A model was also developed that predicts the mechanical stress in the droplet shell and a parametric study was conducted. A one-dimensional model of a slurry-fueled rocket combustion chamber was developed. This model includes the processes of liquid hydrocarbon burnout, secondary atomization, aluminum ignition, and aluminum combustion. Also included is a model for radiant heat transfer from the hot aluminum oxide particles to the chamber walls. Exercising this model shows that only a modest amount of secondary atomization is required to reduce residence times for aluminum burnout, and thereby maintain relatively short chamber lengths. The model also predicts

  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. 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,...

  7. 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...

  8. 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...

  9. 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

  10. 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.

  11. 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...

  12. 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...

  13. AN AIRPLANE WITH UNCONVENTIONALLY PLACED PROPELLER POWER UNIT

    Directory of Open Access Journals (Sweden)

    Jan Červinka

    2017-02-01

    Full Text Available The significance of the influence of operating propellers on the aircraft aerodynamic characteristics is well-known. Wind tunnel testing of an airplane model with operating propellers is a complex task regarding the required similarity of the full-scale and the model case. Matching sufficient similarity in axial and rotational velocities in the propeller slipstream is the primordial condition for the global aerodynamic similarity of the windtunnel testing. An example of the model power units with related devices is presented. Examples of the wind tunnel testing results illustrate the extent of the propeller influence on aerodynamic characteristics of an aircraft of unconventional configuration with power units positioned at the fuselage afterbody.

  14. 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.

  15. 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...

  16. Lifetime prediction of EC, DPA, akardite II and MNA stabilized triple base propellants, comparison of heat generation rate and stabilizer consumption

    NARCIS (Netherlands)

    Boers, M.N.; Klerk, W.P.C. de

    2005-01-01

    A lifetime prediction study is carried out on four triple base propellant compositions by artificial ageing. The ageing effects are studied with High Performance Liquid Chromatography (HPLC) and Heat Flow Calorimetry (HFC) in order to find the most effective stabilizer and to evaluate the advantages

  17. Lifetime prediction of EC, DPA, Akardite II and MNA stabilized triple base propellants, comparison of heat generation rate and stabilizer consumption

    Energy Technology Data Exchange (ETDEWEB)

    Boers, Marco N.; Klerk, Willem (Wim) P.C. de [TNO Defence, Security and Safety, P. O. Box 45, 2280 AA Rijswijk ZH (Netherlands)

    2005-10-01

    A lifetime prediction study is carried out on four triple base propellant compositions by artificial ageing. The ageing effects are studied with High Performance Liquid Chromatography (HPLC) and Heat Flow Calorimetry (HFC) in order to find the most effective stabilizer and to evaluate the advantages and disadvantages of both methods. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

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

    Science.gov (United States)

    2015-06-26

    each one. The GUI contains input boxes for all of the necessary data in order to run QMIL, QPROP, NAFNoise, and to produce Visual Basic ( VBA ) code... VBA macros that will automatically place reference planes for each airfoil section and insert the splined airfoils to their respective reference...Figure 24. Solid propeller exa mple. Figure 25. Hub and spoke propeller design. Figure 26. Alumninum hub design. accessed on May 12, 2015. DC, August

  19. 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.

  20. Cryogenic Propellant Storage and Transfer Engineering Development Unit Hydrogen Tank

    Science.gov (United States)

    Werkheiser, Arthur

    2015-01-01

    The Cryogenic Propellant Storage and Transfer (CPST) project has been a long-running program in the Space Technology Mission Directorate to enhance the knowledge and technology related to handling cryogenic propellants, specifically liquid hydrogen. This particular effort, the CPST engineering development unit (EDU), was a proof of manufacturability effort in support of a flight article. The EDU was built to find and overcome issues related to manufacturability and collect data to anchor the thermal models for use on the flight design.

  1. Integral performance optimum design for multistage solid propellant rocket motors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hongtao (Shaanxi Power Machinery Institute (China))

    1989-04-01

    A mathematical model for integral performance optimization of multistage solid propellant rocket motors is presented. A calculation on a three-stage, volume-fixed, solid propellant rocket motor is used as an example. It is shown that the velocity at burnout of intermediate-range or long-range ballistic missile calculated using this model is four percent greater than that using the usual empirical method.

  2. 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...

  3. Study on Combustion Characteristics and Propelling Projectile Motion Process of Bulk-Loaded Liquid Propellant

    Science.gov (United States)

    Xue, Xiaochun; Yu, Yonggang; Mang, Shanshan

    2017-07-01

    Data are presented showing that the problem of gas-liquid interaction instability is an important subject in the combustion and the propellant projectile motion process of a bulk-loaded liquid propellant gun (BLPG). The instabilities themselves arise from the sources, including fluid motion, to form a combustion gas cavity called Taylor cavity, fluid turbulence and breakup caused by liquid motion relative to the combustion chamber walls, and liquid surface breakup arising from a velocity mismatch on the gas-liquid interface. Typically, small disturbances that arise early in the BLPG combustion interior ballistic cycle can become amplified in the absence of burn rate limiting characteristics. Herein, significant attention has been given to developing and emphasizing the need for better combustion repeatability in the BLPG. Based on this goal, the concept of using different geometries of the combustion chamber is introduced and the concept of using a stepped-wall structure on the combustion chamber itself as a useful means of exerting boundary control on the combustion evolution to thus restrain the combustion instability has been verified experimentally in this work. Moreover, based on this background, the numerical simulation is devoted to a special combustion issue under transient high-pressure and high-temperature conditions, namely, studying the combustion mechanism in a stepped-wall combustion chamber with full monopropellant on one end that is stationary and the other end can move at high speed. The numerical results also show that the burning surface of the liquid propellant can be defined geometrically and combustion is well behaved as ignition and combustion progressivity are in a suitable range during each stage in this combustion chamber with a stepped-wall structure.

  4. How propeller suction is the dominant factor for ship accidents at shallow water conditions

    Science.gov (United States)

    Acar, Dursun; Alpar, Bedri; Ozeren, Sinan

    2017-04-01

    The laminar flow comes to the fore with the disappearance of the several other directions in the internal displacements in the water current. Due to the dominant speed direction during the straightforward motion of the ship, the underwater hull is associated with the continuous flow of laminar currents. The open marine environment acts as a compressible liquid medium because of the presence of many variables about water volume overflow boundaries where the ship is associated. Layers of water rising over the sea surface due to ship's body and the propeller's water push provides loss of liquid lifting force for the ship. These situations change the well-known sea-floor morphology and reliable depth limits, and lead to probable accidents. If the ship block coefficient for the front side is 0.7 or higher, the "squat" will be more on the bow, because the associated factor "displacement volume" causes to the low-pressure environment due to large and rapid turbulence. Thus, the bow sinks further, which faced with liquid's weaker lift force. The vessels Gerardus Mercator, Queen Elizabeth and Costa Concordia had accidents because of unified reasons of squat, fast water mass displacement by hull push and propeller suction interaction. In the case of water mass displacement from the bow side away, that accident occurred in 2005 by the vessel Gerardus Mercator with excessive longitudinal trim angularity in the shallow water. The vessel Costa Concordia (2012), voluminous water displaced from the rear left side was an important factor because of the sharp manoeuvre of that the captain made before the accident. Observations before the accident indicate that full-speed sharp turn provided listed position for the ship from left (port side) in the direction of travel before colliding and then strike a rock on the sloping side of the seabed. The reason why the ship drifted to the left depends mainly the water discharge occurred at the left side of the hull during left-hand rudder

  5. Low-Cost Propellant Launch to LEO from a Tethered Balloon - 'Propulsion Depots' Not 'Propellant Depots'

    Science.gov (United States)

    Wilcox, Brian H.; Schneider, Evan G.; Vaughan, David A.; Hall, Jeffrey L.; Yu, Chi Yau

    2011-01-01

    As we have previously reported, it may be possible to launch payloads into low-Earth orbit (LEO) at a per-kilogram cost that is one to two orders of magnitude lower than current launch systems, using only a relatively small capital investment (comparable to a single large present-day launch). An attractive payload would be large quantities of high-performance chemical rocket propellant (e.g. Liquid Oxygen/Liquid Hydrogen (LO2/LH2)) that would greatly facilitate, if not enable, extensive exploration of the moon, Mars, and beyond.

  6. 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.

  7. 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.

  8. 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)

  9. 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.

  10. Studies of pellet acceleration with arc discharge heated propellants

    International Nuclear Information System (INIS)

    Schuresko, D.D.

    1986-01-01

    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 up to 2 kA at arc voltages ranging from 100-400 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 2-3 fold prompt increase in P/sub breech/ and a delayed increase in P/sub muzzle/; the pellets exit the gun from 0.5-1.0 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

  11. 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

  12. A Simple Method for High-Lift Propeller Conceptual Design

    Science.gov (United States)

    Patterson, Michael; Borer, Nick; German, Brian

    2016-01-01

    In this paper, we present a simple method for designing propellers that are placed upstream of the leading edge of a wing in order to augment lift. Because the primary purpose of these "high-lift propellers" is to increase lift rather than produce thrust, these props are best viewed as a form of high-lift device; consequently, they should be designed differently than traditional propellers. We present a theory that describes how these props can be designed to provide a relatively uniform axial velocity increase, which is hypothesized to be advantageous for lift augmentation based on a literature survey. Computational modeling indicates that such propellers can generate the same average induced axial velocity while consuming less power and producing less thrust than conventional propeller designs. For an example problem based on specifications for NASA's Scalable Convergent Electric Propulsion Technology and Operations Research (SCEPTOR) flight demonstrator, a propeller designed with the new method requires approximately 15% less power and produces approximately 11% less thrust than one designed for minimum induced loss. Higher-order modeling and/or wind tunnel testing are needed to verify the predicted performance.

  13. Phylogenomics of Rhodobacteraceae reveals evolutionary adaptation to marine and non-marine habitats.

    Science.gov (United States)

    Simon, Meinhard; Scheuner, Carmen; Meier-Kolthoff, Jan P; Brinkhoff, Thorsten; Wagner-Döbler, Irene; Ulbrich, Marcus; Klenk, Hans-Peter; Schomburg, Dietmar; Petersen, Jörn; Göker, Markus

    2017-06-01

    Marine Rhodobacteraceae (Alphaproteobacteria) are key players of biogeochemical cycling, comprise up to 30% of bacterial communities in pelagic environments and are often mutualists of eukaryotes. As 'Roseobacter clade', these 'roseobacters' are assumed to be monophyletic, but non-marine Rhodobacteraceae have not yet been included in phylogenomic analyses. Therefore, we analysed 106 genome sequences, particularly emphasizing gene sampling and its effect on phylogenetic stability, and investigated relationships between marine versus non-marine habitat, evolutionary origin and genomic adaptations. Our analyses, providing no unequivocal evidence for the monophyly of roseobacters, indicate several shifts between marine and non-marine habitats that occurred independently and were accompanied by characteristic changes in genomic content of orthologs, enzymes and metabolic pathways. Non-marine Rhodobacteraceae gained high-affinity transporters to cope with much lower sulphate concentrations and lost genes related to the reduced sodium chloride and organohalogen concentrations in their habitats. Marine Rhodobacteraceae gained genes required for fucoidan desulphonation and synthesis of the plant hormone indole 3-acetic acid and the compatible solutes ectoin and carnitin. However, neither plasmid composition, even though typical for the family, nor the degree of oligotrophy shows a systematic difference between marine and non-marine Rhodobacteraceae. We suggest the operational term 'Roseobacter group' for the marine Rhodobacteraceae strains.

  14. Multimode marine engine room simulation system based on field bus technology

    Science.gov (United States)

    Zheng, Huayao; Deng, Linlin; Guo, Yi

    2003-09-01

    Developing multi mode MER (Marine Engine Room) Labs is the main work in Marine Simulation Center, which is the key lab of Communication Ministry of China. It includes FPP (Fixed Pitch Propeller) and CPP (Controllable Pitch Propeller) mode MER simulation systems, integrated electrical propulsion mode MER simulation system, physical mode MER lab, etc. FPP mode simulation system, which was oriented to large container ship, had been completed since 1999, and got second level of Shanghai Municipal Science and Technical Progress award. This paper mainly introduces the recent development and achievements of Marine Simulation Center. Based on the Lon Works field bus, the structure characteristics and control strategies of completely distributed intelligent control network are discussed. The experiment mode of multi-nodes field bus detection and control system is described. Besides, intelligent fault diagnosis technology about some mechatronics integration control systems explored is also involved.

  15. Active Marine Station Metadata

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Active Marine Station Metadata is a daily metadata report for active marine bouy and C-MAN (Coastal Marine Automated Network) platforms from the National Data...

  16. Marine Science

    African Journals Online (AJOL)

    The local communities' eco- nomic activities involve fishing, seaweed farming and ..... and body composition of Nile tilapia (Oreochromis niloticus) fingerlings. ... King JM, Brown CA (2006) River Health Assessment. IUCN Water and Nature ...

  17. Where and What Is Pristine Marine Aerosol?

    Science.gov (United States)

    Russell, L. M.; Frossard, A. A.; Long, M. S.; Burrows, S. M.; Elliott, S.; Bates, T. S.; Quinn, P.

    2014-12-01

    The sources and composition of atmospheric marine aerosol particles have been measured by functional group composition (from Fourier transform infrared spectroscopy) to identify the organic composition of the pristine primary marine (ocean-derived) particles as 65% hydroxyl, 21% alkane, 6% amine, and 7% carboxylic acid functional groups [Frossard et al., 2014a,b]. Pristine but non-primary components from photochemical reactions (likely from biogenic marine vapor emissions) add carboxylic acid groups. Non-pristine contributions include shipping effluent in seawater and ship emissions, which add additional alkane groups (up to 70%), and coastal or continental emissions mix in alkane and carboxylic acid groups. The pristine primary marine (ocean-derived) organic aerosol composition is nearly identical to model generated primary marine aerosol particles from bubbled seawater, indicating that its overall functional group composition is the direct consequence of the organic constituents of the seawater source. While the seawater organic functional group composition was nearly invariant across all three ocean regions studied and the ratio of organic carbon to sodium (OC/Na+) in the generated primary marine aerosol particles remained nearly constant over a broad range of chlorophyll-a concentrations, the generated primary marine aerosol particle alkane group fraction increased with chlorophyll-a concentrations. In addition, the generated primary marine aerosol particles have a hydroxyl group absorption peak location characteristic of monosaccharides and disaccharides, where the seawater hydroxyl group peak location is closer to that of polysaccharides. References Cited Frossard, Amanda A., Lynn M. Russell, Paola Massoli, Timothy S. Bates, and Patricia K. Quinn, "Side-by-Side Comparison of Four Techniques Explains the Apparent Differences in the Organic Composition of Generated and Ambient Marine Aerosol Particles," Aerosol Science and Technology - Aerosol Research Letter

  18. Experimental and theoretical studies on stability of new stabilizers for N-methyl-P-nitroaniline derivative in CMDB propellants

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Qiufan [Xi’an Modern Chemistry Research Institute, Xi’an 710065 (China); Fan, Xuezhong, E-mail: xuezhongfan@126.com [Xi’an Modern Chemistry Research Institute, Xi’an 710065 (China); Li, Jizhen [Xi’an Modern Chemistry Research Institute, Xi’an 710065 (China); Key Laboratory of Applied Surface and Colloid Chemistry, MOE/School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062 (China); Bi, Fuqiang; Fu, Xiaolong; Zhai, Lianjie [Xi’an Modern Chemistry Research Institute, Xi’an 710065 (China)

    2017-04-05

    Highlights: • Five new stabilizers have been designed and synthesized. • The influence of the carbon chain length on the stability of propellants was studied. • Effects of temperature on the reactions of stabilizers and nitrogen oxides were explained. • The new stabilizer n-BNA was one of the most promising stabilizers. - Abstract: Although N-methyl-P-nitroaniline (MNA) was a quite effective stabilizer in composite modified double base (CMDB) propellants, it undergoes crystallization easily from nitroglycerin (NG) during storage. In order to improve its solubility in nitroglycerin (NG) and the stability in propellants, several new stabilizers including N-ethyl-p-nitroaniline (ENA), N-n-propyl-p-nitroaniline (n-PNA), N-i-propyl-p-nitroaniline (i-PNA), N-n-butyl-p-nitroaniline (n-BNA) and N-t-butyl-p-nitroaniline (t-BNA) were designed and synthesized to replace MNA by increasing the carbon chain length. The interaction between NG and different stabilizers was simulation by Materials Studio 5.5 and the stability and the high temperature stability performance of those new stabilizers in propellants were calculated by Gaussian 09. It was found that both the solubility of new stabilizers in NG and the stability and the high temperature stability performance of those in propellants were improved when the carbon chain length of substitution groups on nitrogen atom was increased. Thus, the n-BNA was a most potential stabilizer. Then all properties of the stabilizers were studied experimentally, which was agreement well with the theoretical analysis.

  19. Marine Sciences

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    PNL research in the marine sciences is focused on establishing a basic understanding of the mechanisms of stress and tolerance in marine organisms exposed to contaminants. Several environmental stressors had been investigated in earlier energy-related research. In a landmark study, for example, PNL had established that the severity of fish disease caused by the common infectious agent, Flexobacter columnaris, was seriously aggravated by thermal enhancement and certain ecological factors. Subsequent studies demonstrated that the primary immune response in fish, challenged by columnaris, could be permanently suppressed by comparatively low tritium exposures. The research has suggested that a potential exists for a significant biological impact when an aquatic stressor is added to an ambient background of other stressors, which may include heat, heavy metal ions, radiation or infectious microorganisms. More recently, PNL investigators have shown that in response to heavy metal contaminants, animals synthesize specific proteins (metallothioneins), which bind and sequester metals in the animals, thus decreasing metal mobility and effects. Companion studies with host-specific intracellular pathogens are being used to investigate the effects of heavy metals on the synthesis of immune proteins, which mitigate disease processes. The results of these studies aid in predicting the ecological effects of energy-related contaminants on valued fin and shellfish species

  20. 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.

  1. Design and Fabrication of a 200N Thrust Rocket Motor Based on NH4ClO4+Al+HTPB as Solid Propellant

    Science.gov (United States)

    Wahid, Mastura Ab; Ali, Wan Khairuddin Wan

    2010-06-01

    The development of rocket motor using potassium nitrate, carbon and sulphur mixture has successfully been developed by researchers and students from UTM and recently a new combination for solid propellant is being created. The new solid propellant will combine a composition of Ammonium perchlorate, NH4ClO4 with aluminium, Al and Hydroxyl Terminated Polybutadiene, HTPB as the binder. It is the aim of this research to design and fabricate a new rocket motor that will produce a thrust of 200N by using this new solid propellant. A static test is done to obtain the thrust produced by the rocket motor and analyses by observation and also calculation will be done. The experiment for the rocket motor is successful but the thrust did not achieve its required thrust.

  2. 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.

  3. Fillet proximate composition, lipid quality, yields, and organoleptic quality of Mediterranean-farmed marine fish: A review with emphasis on new species.

    Science.gov (United States)

    Grigorakis, Kriton

    2017-09-22

    Species diversification in Mediterranean mariculture involves various important fish that contribute to the diet of many human populations. These include meagres (Sciaenidae), flatfishes, mullets, and various sparids. Their quality aspects (yields, fillet proximate composition, and lipid quality) are discussed in this review. Their filleting yield is mostly 40-45%. The viscerosomatic index ranges from 1.5% to 14%, depending on species. Low muscle fat contents of flatfishes and meagres differentiate them from the rest of the farmed species. Farmed fish contain high n-3 polyunsaturates fatty acids (PUFA; 12.3-36.3% vs. 5.48-37.2% in the wild) and have higher muscle fat and n-6 PUFA contents (mainly 18:2 n-6) than their wild counterparts. The aquaculture management, diet, and season can affect fillet composition and fatty acids, while season (i.e. food availability and maturation) largely affects lipid quality in wild fish. Data on the sensory quality of Mediterranean-farmed species are mainly limited to whether specific management differentiates the sensory quality; thus, further development of tools for sensory analysis is required. Observations on the quality features in farmed Mediterranean fish indicate that species diversification can also provide product diversification based on different commercial weights and fillet quality specifications.

  4. Modeling comprehensive chemical composition of weathered oil following a marine spill to predict ozone and potential secondary aerosol formation and constrain transport pathways

    Science.gov (United States)

    Drozd, Greg T.; Worton, David R.; Aeppli, Christoph; Reddy, Christopher M.; Zhang, Haofei; Variano, Evan; Goldstein, Allen H.

    2015-11-01

    Releases of hydrocarbons from oil spills have large environmental impacts in both the ocean and atmosphere. Oil evaporation is not simply a mechanism of mass loss from the ocean, as it also causes production of atmospheric pollutants. Monitoring atmospheric emissions from oil spills must include a broad range of volatile organic compounds (VOC), including intermediate-volatile and semivolatile compounds (IVOC, SVOC), which cause secondary organic aerosol (SOA) and ozone production. The Deepwater Horizon (DWH) disaster in the northern Gulf of Mexico during Spring/Summer of 2010 presented a unique opportunity to observe SOA production due to an oil spill. To better understand these observations, we conducted measurements and modeled oil evaporation utilizing unprecedented comprehensive composition measurements, achieved by gas chromatography with vacuum ultraviolet time of flight mass spectrometry (GC-VUV-HR-ToFMS). All hydrocarbons with 10-30 carbons were classified by degree of branching, number of cyclic rings, aromaticity, and molecular weight; these hydrocarbons comprise ˜70% of total oil mass. Such detailed and comprehensive characterization of DWH oil allowed bottom-up estimates of oil evaporation kinetics. We developed an evaporative model, using solely our composition measurements and thermodynamic data, that is in excellent agreement with published mass evaporation rates and our wind-tunnel measurements. Using this model, we determine surface slick samples are composed of oil with a distribution of evaporative ages and identify and characterize probable subsurface transport of oil.

  5. Marine oils: Complex, confusing, confounded?

    Directory of Open Access Journals (Sweden)

    Benjamin B. Albert

    2016-09-01

    Full Text Available Marine oils gained prominence following the report that Greenland Inuits who consumed a high-fat diet rich in long-chain n-3 polyunsaturated fatty acids (PUFAs also had low rates of cardiovascular disease. Marine n-3 PUFAs have since become a billion dollar industry, which will continue to grow based on current trends. However, recent systematic reviews question the health benefits of marine oil supplements, particularly in the prevention of cardiovascular disease. Marine oils constitute an extremely complex dietary intervention for a number of reasons: i the many chemical compounds they contain; ii the many biological processes affected by n-3 PUFAs; iii their tendency to deteriorate and form potentially toxic primary and secondary oxidation products; and iv inaccuracy in the labelling of consumer products. These complexities may confound the clinical literature, limiting the ability to make substantive conclusions for some key health outcomes. Thus, there is a pressing need for clinical trials using marine oils whose composition has been independently verified and demonstrated to be minimally oxidised. Without such data, it is premature to conclude that n-3 PUFA rich supplements are ineffective.

  6. Isotopic composition of daily precipitation along the southern foothills of the Himalayas: impact of marine and continental sources of atmospheric moisture

    Directory of Open Access Journals (Sweden)

    G. Jeelani

    2018-06-01

    Full Text Available The flow of the Himalayan rivers, a key source of fresh water for more than a billion people primarily depends upon the strength, behaviour and duration of the Indian summer monsoon (ISM and the western disturbances (WD, two contrasting circulation regimes of the regional atmosphere. An analysis of the 2H and 18O isotope composition of daily precipitation collected along the southern foothills of the Himalayas, combined with extensive backward trajectory modelling, was used to gain deeper insight into the mechanisms controlling the isotopic composition of precipitation and the origin of atmospheric moisture and precipitation during ISM and WD periods. Daily precipitation samples were collected during the period from September 2008 to December 2011 at six stations, extending from Srinagar in the west (Kashmir state to Dibrugarh in the east (Assam state. In total, 548 daily precipitation samples were collected and analysed for their stable isotope composition. It is suggested that the gradual reduction in the 2H and 18O content of precipitation in the study region, progressing from δ18O values close to zero down to ca. −10 ‰ in the course of ISM evolution, stems from regional, large-scale recycling of moisture-driven monsoonal circulation. Superimposed on this general trend are short-term fluctuations of the isotopic composition of rainfall, which might have stem from local effects such as enhanced convective activity and the associated higher degree of rainout of moist air masses (local amount effect, the partial evaporation of raindrops, or the impact of isotopically heavy moisture generated in evapotranspiration processes taking place in the vicinity of rainfall sampling sites. Seasonal footprint maps constructed for three stations representing the western, central and eastern portions of the Himalayan region indicate that the influence of monsoonal circulation reaches the western edges of the Himalayan region. While the characteristic

  7. Food enrichment with marine phospholipid emulsions

    DEFF Research Database (Denmark)

    Lu, Henna Fung Sieng; Nielsen, Nina Skall; Baron, Caroline P.

    marine PL emulsions with and without addition of fish oil. The oxidative stability of marine PL emulsions was significantly influenced by the chemical composition of marine PL used for emulsions preparation. For instance, emulsions with good oxidative stability could be obtained when using raw materials...... with high purity, low fish oil content and high PL, cholesterol and α-tocopherol content. In addition, non-enzymatic browning reactions may also affect the oxidative stability of the marine PL emulsion. These reactions included Strecker degradation and pyrrolization, and their occurrence were due......Many studies have shown that marine phospholipids (PL) provide more advantages than fish oil. They seem to have better bioavailability, better resistance towards oxidation and higher content of eicosapentaenoic acids and docosahexaenoic acids than fish oil, which essentially contains triglycerides...

  8. Producing propellants from water in lunar soil using solar lasers

    Science.gov (United States)

    de Morais Mendonca Teles, Antonio

    The exploration of the Solar System is directly related to the efficiency of engines designed to explore it, and consequently, to the propulsion techniques, materials and propellants for those engines. With the present day propulsion techniques it is necessary great quantities of propellants to impulse a manned spacecraft to Mars and beyond in the Solar System, which makes these operations financially very expensive because of the costs involved in launching it from planet Earth, due to its high gravity field strength. To solve this problem, it is needed a planetary place with smaller gravity field strength, near to the Earth and with great quantities of substances at the surface necessary for the in-situ production of propellants for spacecrafts. The only place available is Earth's natural satellite the Moon. So, here in this paper, I propose the creation of a Lunar Propellant Manufacturer. It is a robot-spacecraft which can be launched from Earth using an Energia Rocket, and to land on the Moon in an area (principally near to the north pole where it was discovered water molecules ice recently) with great quantities of oxygen and hydrogen (propellants) in the silicate soil, previously observed and mapped by spacecrafts in lunar orbit, for the extraction of those molecules from the soil and the in-situ production of the necessary propellants. The Lunar Propellant Manufacturer (LPM) spacecraft consists of: 1) a landing system with four legs (extendable) and rovers -when the spacecraft touches down, the legs retract in order that two apparatuses, analogue to tractor's wheeled belts parallel sided and below the spacecraft, can touch firmly the ground -it will be necessary for the displacement of the spacecraft to new areas with richer propellants content, when the early place has already exhausted in propellants; 2) a digging machine -a long, resistant extendable arm with an excavator hand, in the outer part of the spacecraft -it will extend itself to the ground

  9. Numerical Prediction of Magnetic Cryogenic Propellant Storage in Reduced Gravity

    Science.gov (United States)

    Marchetta, J. G.; Hochstein, J. I.

    2002-01-01

    Numerical Prediction of Magnetic Cryogenic Propellant Storage in Reduced strong evidence that a magnetic positioning system may be a feasible alternative technology for use in the management of cryogenic propellants onboard spacecraft. The results of these preliminary studies have indicated that further investigation of the physical processes and potential reliability of such a system is required. The utility of magnetic fields as an alternative method in cryogenic propellant management is dependent on its reliability and flexibility. Simulations and experiments have previously yielded evidence in support of the magnetic positive positioning (MPP) process to predictably reorient LOX for a variety of initial conditions. Presently, though, insufficient evidence has been established to support the use of magnetic fields with respect to the long-term storage of cryogenic propellants. Current modes of propellant storage have met with a moderate level of success and are well suited for short duration missions using monopropellants. However, the storage of cryogenic propellants warrants additional consideration for long-term missions. For example, propellant loss during storage is due to vaporization by incident solar radiation and the vaporized ullage must be vented to prevent excessive pressurization of the tank. Ideally, positioning the fluid in the center of the tank away from the tank wall will reduce vaporization by minimizing heat transfer through the tank wall to the liquid. A second issue involves the capability of sustaining a stable fluid configuration at tank center under varying g-levels or perturbations propellant storage. Results presented herein include comparisons illustrating the influence of gravity, fluid volume, and the magnetic field on a paramagnetic fluid, LOX. The magnetic Bond number is utilized as predictive correlating parameter for investigating these processes. A dimensionless relationship between the Bom and Bo was sought with the goal of

  10. Plane boundary effects on characteristics of propeller jets

    Science.gov (United States)

    Wei, Maoxing; Chiew, Yee-Meng; Hsieh, Shih-Chun

    2017-10-01

    The flow properties of a propeller jet in the presence of a plane bed boundary were investigated using the particle image velocimetry technique. Three clearance heights, Z b = 2 D p, D p, and 0.5 D p, where D p = propeller diameter, were used to examine boundary effects on the development of the jet. In each case, the mean flow properties and turbulence characteristics were measured in a larger field of view than those used in past studies. Both the streamwise and transverse flow fields were measured to obtain the three-dimensional characteristics of the propeller jet. Similar to a confined offset jet, the propeller jet also exhibits a wall attachment behavior when it is placed near a plane boundary. As a result, in contrast to its unconfined counterpart, the confined propeller jet features three regions, namely the free jet, impingement and wall jet regions. The study shows that the extent of each region varies under different clearance heights. The development of the mean flow and turbulence characteristics associated with varying clearance heights are compared to illustrate boundary effects in these regions. In the impingement region, the measured transverse flow fields provide new insights on the lateral motions induced by the impingement of the swirling jet. In the wall jet region, observations reveal that the jet behaves like a typical three-dimensional wall jet and its axial velocity profiles show good agreement with the classical wall jet similarity function.

  11. Reconstruction of pressure sores with perforator-based propeller flaps.

    Science.gov (United States)

    Jakubietz, Rafael G; Jakubietz, Danni F; Zahn, Robert; Schmidt, Karsten; Meffert, Rainer H; Jakubietz, Michael G

    2011-03-01

    Perforator flaps have been successfully used for reconstruction of pressure sores. Although V-Y advancement flaps approximate debrided wound edges, perforator-based propeller flaps allow rotation of healthy tissue into the defect. Perforator-based propeller flaps were planned in 13 patients. Seven pressure sores were over the sacrum, five over the ischial tuberosity, and one on the tip of the scapula. Three patients were paraplegic, six were bedridden, and five were ambulatory. In three patients, no perforators were found. In 10 patients, propeller flaps were transferred. In two patients, total flap necrosis occurred, which was reconstructed with local advancement flaps. In two cases, a wound dehiscence occurred and had to be revised. One hematoma required evacuation. No further complications were noted. No recurrence at the flap site occurred. Local perforator flaps allow closure of pressure sores without harvesting muscle. The propeller version has the added benefit of transferring tissue from a distant site, avoiding reapproximation of original wound edges. Twisting of the pedicle may cause torsion and venous obstruction. This can be avoided by dissecting a pedicle of at least 3 cm. Propeller flaps are a safe option for soft tissue reconstruction of pressure sores. © Thieme Medical Publishers.

  12. 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.

  13. Advanced technologies available for future solid propellant grains

    Energy Technology Data Exchange (ETDEWEB)

    Thepenier, J. [SNPE Propulsion, St Medard en Jalles (France); Fonblanc, G. [SNPE Propulsion, Vert le Petit (France). Centre de Recherche de Bouchet

    2001-06-01

    Significant advances have been made during the last decade in several fields of solid propulsion: the advances have enabled new savings in the motor development phase and in recurring costs, because they help limit the number of prototypes and tests. The purpose of the paper is to describe the improvements achieved by SNPE in solid grain technologies, making these technologies available for new developments in more efficient and reliable future SRMs: new energetic molecules, new solid propellants, new processes for grain manufacturing, quick response grain design tools associated with advanced models for grain performance predictions. Using its expertise in chemical synthesis, SNPE develops new molecules to fit new energetic material requirements. Tests based on new propellant formulations have produced good results in the propellant performance/safety behavior ratio. New processes have been developed simultaneously to reduce the manufacturing costs of the new propellants. In addition, the grain design has been optimized by using the latest generation of predictive theoretical tools supported by a large data bank of experimental parameters resulting from over 30 years' experience in solid propulsion: computer-aided method for the preliminary grain design; advanced models for SRM operating and performance predictions. All these technologies are available for industrial applications in future developments of solid propellant grains. (author)

  14. Recent Advances and Applications in Cryogenic Propellant Densification Technology

    Science.gov (United States)

    Tomsik, Thomas M.

    2000-01-01

    This purpose of this paper is to review several historical cryogenic test programs that were conducted at the NASA Glenn Research Center (GRC), Cleveland, Ohio over the past fifty years. More recently these technology programs were intended to study new and improved denser forms of liquid hydrogen (LH2) and liquid oxygen (LO2) cryogenic rocket fuels. Of particular interest are subcooled cryogenic propellants. This is due to the fact that they have a significantly higher density (eg. triple-point hydrogen, slush etc.), a lower vapor pressure and improved cooling capacity over the normal boiling point cryogen. This paper, which is intended to be a historical technology overview, will trace the past and recent development and testing of small and large-scale propellant densification production systems. Densifier units in the current GRC fuels program, were designed and are capable of processing subcooled LH2 and L02 propellant at the X33 Reusable Launch Vehicle (RLV) scale. One final objective of this technical briefing is to discuss some of the potential benefits and application which propellant densification technology may offer the industrial cryogenics production and end-user community. Density enhancements to cryogenic propellants (LH2, LO2, CH4) in rocket propulsion and aerospace application have provided the opportunity to either increase performance of existing launch vehicles or to reduce the overall size, mass and cost of a new vehicle system.

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

    OpenAIRE

    Agoes Santoso; Irfan Syarif Arief; Anggara Tio Kurniawan

    2017-01-01

    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 disc...

  16. 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...

  17. Marine Science

    African Journals Online (AJOL)

    (1992), they are the most abundant meiobenthic group, have a ubiquitous distribution and high diversity. .... munity composition and diversity to that of the natu- ral mangrove stand? ...... turing meiofauna of a tropical estuarine beach: Field experiment. ... littoral Meiobenthos in relation to phytoplankton sedimentation in the ...

  18. Flow measurement around a model ship with propeller and rudder

    Energy Technology Data Exchange (ETDEWEB)

    Van, S H; Yoon, H S; Lee, Y Y; Park, I R [Korea Research Institute of Ships and Ocean Engineering, KORDI, Marine Transportation Systems Laboratory, Daejeon (Korea); Kim, W J [Mokpo National University, Department of Naval Architecture and Marine Engineering, Jeonnam (Korea)

    2006-04-15

    For the design of hull forms with better resistance and propulsive performance, it is essential to understand flow characteristics, such as wave and wake development, around a ship. Experimental data detailing the local flow characteristics are invaluable for the validation of the physical and numerical modeling of computational fluid dynamics (CFD) codes, which are recently gaining attention as efficient tools for hull form evaluation. This paper describes velocity and wave profiles measured in the towing tank for the KRISO 138,000 m{sup 3} LNG carrier model with propeller and rudder. The effects of propeller and rudder on the wake and wave profiles in the stern region are clearly identified. The results contained in this paper can provide an opportunity to explore integrated flow phenomena around a model ship in the self-propelled condition, and can be added to the International Towing Tank Conference benchmark data for CFD validation as the previous KCS and KVLCC cases. (orig.)

  19. Flow measurement around a model ship with propeller and rudder

    Science.gov (United States)

    van, S. H.; Kim, W. J.; Yoon, H. S.; Lee, Y. Y.; Park, I. R.

    2006-04-01

    For the design of hull forms with better resistance and propulsive performance, it is essential to understand flow characteristics, such as wave and wake development, around a ship. Experimental data detailing the local flow characteristics are invaluable for the validation of the physical and numerical modeling of computational fluid dynamics (CFD) codes, which are recently gaining attention as efficient tools for hull form evaluation. This paper describes velocity and wave profiles measured in the towing tank for the KRISO 138,000 m3 LNG carrier model with propeller and rudder. The effects of propeller and rudder on the wake and wave profiles in the stern region are clearly identified. The results contained in this paper can provide an opportunity to explore integrated flow phenomena around a model ship in the self-propelled condition, and can be added to the International Towing Tank Conference benchmark data for CFD validation as the previous KCS and KVLCC cases.

  20. A stochastic pocket model for aluminum agglomeration in solid propellants

    Energy Technology Data Exchange (ETDEWEB)

    Gallier, Stany [SNPE Materiaux Energetiques, Vert le Petit (France)

    2009-04-15

    A new model is derived to estimate the size and fraction of aluminum agglomerates at the surface of a burning propellant. The basic idea relies on well-known pocket models in which aluminum is supposed to aggregate and melt within pocket volumes imposed by largest oxidizer particles. The proposed model essentially relaxes simple assumptions of previous pocket models on propellant structure by accounting for an actual microstructure obtained by packing. The use of statistical tools from stochastic geometry enables to determine a statistical pocket size volume and hence agglomerate diameter and agglomeration fraction. Application to several AP/Al propellants gives encouraging results that are shown to be superior to former pocket models. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  1. 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.

  2. Bifurcations of propellant burning rate at oscillatory pressure

    Energy Technology Data Exchange (ETDEWEB)

    Novozhilov, Boris V. [N. N. Semenov Institute of Chemical Physics, Russian Academy of Science, 4 Kosygina St., Moscow 119991 (Russian Federation)

    2006-06-15

    A new phenomenon, the disparity between pressure and propellant burning rate frequencies, has revealed in numerical studies of propellant burning rate response to oscillatory pressure. As is clear from the linear approximation, under small pressure amplitudes, h, pressure and propellant burning rate oscillations occur with equal period T (T-solution). In the paper, however, it is shown that at a certain critical value of the parameter h the system in hand undergoes a bifurcation so that the T-solution converts to oscillations with period 2T (2T-solution). When the bifurcation parameter h increases, the subsequent behavior of the system becomes complicated. It is obtained a sequence of period doubling to 4T-solution and 8T-solution. Beyond a certain value of the bifurcation parameter h an apparently fully chaotic solution is found. These effects undoubtedly should be taken into account in studies of oscillatory processes in combustion chambers. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  3. 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.

  4. The Effect of Slipstream Obstructions on Air Propellers

    Science.gov (United States)

    Lesley, E P; Woods, B M

    1924-01-01

    The screw propeller on airplanes is usually placed near other objects, and hence its performance may be modified by them. Results of tests on propellers free from slip stream obstructions, both fore and aft, are therefore subject to correction, for the effect of such obstructions and the purpose of the investigation was to determine the effect upon the thrust and torque coefficients and efficiency, for previously tested air propellers, of obstructions placed in the slip stream, it being realized that such previous tests had been conducted under somewhat ideal conditions that are impracticable of realization in flight. Simple geometrical forms were used for the initial investigation. Such forms offered the advantage of easy, exact reproduction at another time or in other laboratories, and it was believed that the effects of obstructions usually encountered might be deduced or surmise from those chosen.

  5. Towards a renewal of the propeller in aeronautics

    Science.gov (United States)

    Berger, D.; Jacquet, P.

    1985-01-01

    The reasons for reconsidering the propeller for aircraft propulsion, the areas of application, and necessary developments are considered. Rising fuel costs and an increasing theoretical and experimental data base for turboprop engines have demonstrated that significant cost savings can be realized by the use of propellers. Propellers are well-suited to powering aircraft traveling at speeds up to Mach 0.65. Work is progressing on the development of a 150 seat aircraft which has a cruise speed of Mach 0.8, powered by a turboprop attached to an engine of 15,000 shp. Aeroelasticity analyses ae necessary in order to characterize the behavior of thin profile propfan blades, particularly to predict the oscillations through the entire functional range. High-power reducers must be developed, and the level of cabin noise must be controlled to less than 90 dB. Commercial applications are predicted for turboprops in specific instances.

  6. Concept and performance study of turbocharged solid propellant ramjet

    Science.gov (United States)

    Li, Jiang; Liu, Kai; Liu, Yang; Liu, Shichang

    2018-06-01

    This study proposes a turbocharged solid propellant ramjet (TSPR) propulsion system that integrates a turbocharged system consisting of a solid propellant (SP) air turbo rocket (ATR) and the fuel-rich gas generator of a solid propellant ramjet (SPR). First, a suitable propellant scheme was determined for the TSPR. A solid hydrocarbon propellant is used to generate gas for driving the turbine, and a boron-based fuel-rich propellant is used to provide fuel-rich gas to the afterburner. An appropriate TSPR structure was also determined. The TSPR's thermodynamic cycle was analysed to prove its theoretical feasibility. The results showed that the TSPR's specific cycle power was larger than those of SP-ATR and SPR and thermal efficiency was slightly less than that of SP-ATR. Overall, TSPR showed optimal performance in a wide flight envelope. The specific impulses and specific thrusts of TSPR, SP-ATR, and SPR in the flight envelope were calculated and compared. TSPR's flight envelope roughly overlapped that of SP-ATR, its specific impulse was larger than that of SP-ATR, and its specific thrust was larger than those of SP-ATR and SPR. Attempts to improve the TSPR off-design performance prompted our proposal of a control plan for off-design codes in which both the turbocharger corrected speed and combustor excess gas coefficient are kept constant. An off-design performance model was established by analysing the TSPR working process. We concluded that TSPR with a constant corrected speed had wider flight envelope, higher thrust, and higher specific impulse than TSPR with a constant physical speed determined by calculating the performance of off-design TSPR codes under different control plans. The results of this study can provide a reference for further studies on TSPRs.

  7. An investigation on thermal decomposition of DNTF-CMDB propellants

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Wei; Wang, Jiangning; Ren, Xiaoning; Zhang, Laying; Zhou, Yanshui [Xi' an Modern Chemistry Research Institute, Xi' an 710065 (China)

    2007-12-15

    The thermal decomposition of DNTF-CMDB propellants was investigated by pressure differential scanning calorimetry (PDSC) and thermogravimetry (TG). The results show that there is only one decomposition peak on DSC curves, because the decomposition peak of DNTF cannot be separated from that of the NC/NG binder. The decomposition of DNTF can be obviously accelerated by the decomposition products of the NC/NG binder. The kinetic parameters of thermal decompositions for four DNTF-CMDB propellants at 6 MPa were obtained by the Kissinger method. It is found that the reaction rate decreases with increasing content of DNTF. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  8. 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

  9. Low cost manned Mars mission based on indigenous propellant production

    Science.gov (United States)

    Bruckner, A. P.; Cinnamon, M.; Hamling, S.; Mahn, K.; Phillips, J.; Westmark, V.

    1993-01-01

    The paper describes a low-cost approach to the manned exploration of Mars (which involves an unmanned mission followed two years later by a manned mission) based on near-term technologies and in situ propellant production. Particular attention is given to the basic mission architecture and its major components, including the orbital analysis, the unmanned segment, the Earth Return Vehicle, the aerobrake design, life sciences, guidance, communications, power, propellant production, the surface rovers, and Mars science. Also discussed are the cost per mission over an assumed 8-yr initiative.

  10. Proof-of-concept automation of propellant processing

    Science.gov (United States)

    Ramohalli, Kumar; Schallhorn, P. A.

    1989-01-01

    For space-based propellant production, automation of the process is needed. Currently, all phases of terrestrial production have some form of human interaction. A mixer was acquired to help perform the tasks of automation. A heating system to be used with the mixer was designed, built, and installed. Tests performed on the heating system verify design criteria. An IBM PS/2 personal computer was acquired for the future automation work. It is hoped that some the mixing process itself will be automated. This is a concept demonstration task; proving that propellant production can be automated reliably.

  11. 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.

  12. Cryogenic propellant management: Integration of design, performance and operational requirements

    Science.gov (United States)

    Worlund, A. L.; Jamieson, J. R., Jr.; Cole, T. W.; Lak, T. I.

    1985-01-01

    The integration of the design features of the Shuttle elements into a cryogenic propellant management system is described. The implementation and verification of the design/operational changes resulting from design deficiencies and/or element incompatibilities encountered subsequent to the critical design reviews are emphasized. Major topics include: subsystem designs to provide liquid oxygen (LO2) tank pressure stabilization, LO2 facility vent for ice prevention, liquid hydrogen (LH2) feedline high point bleed, pogo suppression on the Space Shuttle Main Engine (SSME), LO2 low level cutoff, Orbiter/engine propellant dump, and LO2 main feedline helium injection for geyser prevention.

  13. The effect of growth phase on the lipid class, fatty acid and sterol composition in the marine dinoflagellate, Gymnodinium sp. in batch culture.

    Science.gov (United States)

    Mansour, Maged P; Volkman, John K; Blackburn, Susan I

    2003-05-01

    We have studied the effects of growth phase on the lipid composition in batch cultures of Gymnodinium sp. CS-380/3 over 43 days of culturing. The lipid content increased two fold, from late logarithmic (day 6) to linear growth phase (day 22) then decreased at stationary phase (day 43) while the lipid yield (mg l(-1)) increased 30-fold from day 6 to 30 mg l(-1) at day 43. Changes in fatty acid content mirrored those observed for the total lipid, while the sterol content continued to increase with culture age through to stationary phase. The largest changes occurred in the lipid classes, especially the polar lipids and triacylglycerols (oil). The proportion of triacylglycerols increased from 8% (of total lipids) at day 6 to 30% at day 43, with a concomitant decrease in the polar lipid fraction. The proportions of 16:0 and DHA [22:6(n-3)] increased while those of 18:5(n-3) and EPA [20:5(n-3)] decreased with increasing culture age. The proportion of the major sterol, dinosterol, decreased from 41% (day 6) to 29% (day 43), while the major dinostanol epimer (23R,24R) increased from 33% (day 6) to 38% (day 22). Despite small changes in the proportion of the main sterols, the same sterols were present at all stages of growth, indicating their value as a chemotaxonomic tool for distinguishing between strains within the same genus. Growth phase could be a useful variable for optimising the oil and DHA content with potential for aquaculture feeds and a source of DHA-rich oils for nutraceuticals.

  14. Is Ammonification Rate in Marine Sediment Related to Plankton Composition and Abundance? A Time-series Study in Villefranche Bay (NW Mediterranean)

    Science.gov (United States)

    Fernex, François E.; Braconnot, Jean-Claude; Dallot, Serge; Boisson, Michel

    1996-09-01

    Observations were made near Cap Ferrat (Station B, about 80 m in water depth) France, in the water column and in the sediment, in order to evaluate to what extent variations in the ammonia and nitrate concentrations of the sediments are related to plankton population abundance and composition. Nitrate, nitrite, ammonia and chlorophyll awere measured several times during 1987 to 1989, at two depths (1 and 40 m). Copepods and salps in the upper 75 m of the water column were counted several times a week from 1987 to 1990. Ammonia and nitrate concentrations and ammonification rate were determined in the underlying sediments. During Spring 1987, phytoplankton biomass showed a maximum at the end of March; copepod populations increased regularly till the end of April, and salps increased from this time to the end of May. These populations were not so well developed during Spring 1988 and 1989. During the blooms, salp were mainly represented by Thalia democratica. The biomass of phytoplankton and zooplankton was low in summer. The sequence suggests that the copepod decline was related to reduced food levels after the phytoplankton decline. Salp population growth was not at the expense of phytoplankton and it can be assumed that the salp fed on other material. In 1987 and 1988, maximum organic nitrogen concentration in the bottom sediment and maximum ammonification rate directly followed the salp spring bloom. In 1987, the highest ammonification rate measured in the surficial sediment (0-2 cm) reached 0·05 μ M cm 3day -1(in June). In 1990, the rate exceeded 0·1 μM cm -3 day -1during an important salp bloom. Therefore, it seems that the sinking of salp fecal pellets plays an important part in the transfer of organic matter to the bottom, and microbial activity in the surficial sediment leads to mineralization of a great part of the organic nitrogen quickly after its deposition.

  15. Altitude Testing of Large Liquid Propellant Engines

    Science.gov (United States)

    Maynard, Bryon T.; Raines, Nickey G.

    2010-01-01

    The National Aeronautics and Space Administration entered a new age on January 14, 2004 with President Bush s announcement of the creation the Vision for Space Exploration that will take mankind back to the Moon and on beyond to Mars. In January, 2006, after two years of hard, dedicated labor, engineers within NASA and its contractor workforce decided that the J2X rocket, based on the heritage of the Apollo J2 engine, would be the new engine for the NASA Constellation Ares upper stage vehicle. This engine and vehicle combination would provide assured access to the International Space Station to replace that role played by the Space Shuttle and additionally, would serve as the Earth Departure Stage, to push the Crew Excursion Vehicle out of Earth Orbit and head it on a path for rendezvous with the Moon. Test as you fly, fly as you test was chosen to be the guiding philosophy and a pre-requisite for the engine design, development, test and evaluation program. An exhaustive survey of national test facility assets proved the required capability to test the J2X engine at high altitude for long durations did not exist so therefore, a high altitude/near space environment testing capability would have to be developed. After several agency concepts the A3 High Altitude Testing Facility proposal was selected by the J2X engine program on March 2, 2007 and later confirmed by a broad panel of NASA senior leadership in May 2007. This facility is to be built at NASA s John C. Stennis Space Center located near Gulfport, Mississippi. 30 plus years of Space Shuttle Main Engine development and flight certification testing makes Stennis uniquely suited to support the Vision For Space Exploration Return to the Moon. Propellant handling infrastructure, engine assembly facilities, a trained and dedicated workforce and a broad and varied technical support base will all ensure that the A3 facility will be built on time to support the schedule needs of the J2X engine and the ultimate flight

  16. Four-quadrant propeller modeling: A low-order harmonic approximation

    Digital Repository Service at National Institute of Oceanography (India)

    Haeusler, A.J; Saccon, A.; Hauser, J; Pascoal, A.M.; Aguiar, A.P.

    . We explore the connection between the propeller thrust, torque, and efficiency curves and the lift and drag curves of the propeller blades. The model originates from a well-known four-quadrant model, based on a sinusoidal approximation...

  17. Neural Network Predictions of the 4-Quadrant Wageningen Propeller Series (CD-ROM)

    National Research Council Canada - National Science Library

    Roddy, Robert F; Hess, David E; Faller, Will

    2006-01-01

    .... This report describes the development of feedforward neural network (FFNN) predictions of four-quadrant thrust and torque behavior for the Wageningen B-Screw Series of propellers and for two Wageningen ducted propeller series...

  18. ISO 15859 Propellant and Fluid Specifications: A Review and Comparison with Military and NASA Specifications

    Science.gov (United States)

    Greene, Ben; McClure, Mark B.; Baker, David L.

    2006-01-01

    This work presents an overview of the International Organization for Standardization (ISO) 15859 International Standard for Space Systems Fluid Characteristics, Sampling and Test Methods Parts 1 through 13 issued in June 2004. These standards establish requirements for fluid characteristics, sampling, and test methods for 13 fluids of concern to the propellant community and propellant characterization laboratories: oxygen, hydrogen, nitrogen, helium, nitrogen tetroxide, monomethylhydrazine, hydrazine, kerosene, argon, water, ammonia, carbon dioxide, and breathing air. A comparison of the fluid characteristics, sampling, and test methods required by the ISO standards to the current military and NASA specifications, which are in use at NASA facilities and elsewhere, is presented. Many ISO standards composition limits and other content agree with those found in the applicable parts of NASA SE-S-0073, NASA SSP 30573, military performance standards and details, and Compressed Gas Association (CGA) commodity specifications. The status of a current project managed at NASA Johnson Space Center White Sands Test Facility (WSTF) to rewrite these documents is discussed.

  19. Optimization of focused ultrasonic extraction of propellant components determined by gas chromatography/mass spectrometry.

    Science.gov (United States)

    Fryš, Ondřej; Česla, Petr; Bajerová, Petra; Adam, Martin; Ventura, Karel

    2012-09-15

    A method for focused ultrasonic extraction of nitroglycerin, triphenyl amine and acetyl tributyl citrate presented in double-base propellant samples following by the gas chromatography/mass spectrometry analysis was developed. A face-centered central composite design of the experiments and response surface modeling was used for optimization of the time, amplitude and sample amount. The dichloromethane was used as the extractant solvent. The optimal extraction conditions with respect to the maximum yield of the lowest abundant compound triphenyl amine were found at the 20 min extraction time, 35% amplitude of ultrasonic waves and 2.5 g of the propellant sample. The results obtained under optimal conditions were compared with the results achieved with validated Soxhlet extraction method, which is typically used for isolation and pre-concentration of compounds from the samples of explosives. The extraction yields for acetyl tributyl citrate using both extraction methods were comparable; however, the yield of ultrasonic extraction of nitroglycerin and triphenyl amine was lower than using Soxhlet extraction. The possible sources of different extraction yields are estimated and discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Numerically-based ducted propeller design using vortex lattice lifting line theory

    OpenAIRE

    Stubblefield, John M.

    2008-01-01

    CIVINS (Civilian Institutions) Thesis document This thesis used vortex lattice lifting line theory to model an axisymmetrical-ducted propeller with no gap between the duct and the propeller. The theory required to model the duct and its interaction with the propeller were discussed and implemented in Open-source Propeller Design and Analysis Program (OpenProp). Two routines for determining the optimum circulation distribution were considered, and a method based on calculus of variation...

  1. Propeller efficiency at full scale : measurement system and mathematical model design

    NARCIS (Netherlands)

    Muntean, T.V.

    2012-01-01

    What is propeller efficiency at full scale? This question is asked equally by ship operators and by propeller and propulsion system manufacturers. The question reflects the need to measure propeller efficiency at full physical scale and during regular operation of the vessel. The question has a

  2. 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

  3. 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,

  4. Green propellant propulsion concepts for space transportation and technology development needs

    NARCIS (Netherlands)

    Haeseler, D.; Bombelli, V.; Vuillermoz, P.; Lo, R.; Maree, A.G.M.; Caramelli, F.

    2004-01-01

    A study has been performed under contract from ESA/ESTEC identifying the development needs in Europe in the field of new green propellant utilization. Criteria for green propellants are defined and discussed. Promising propellants are identified together with their rating w.r.t. those criteria, in

  5. 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

  6. 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

  7. 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

  8. MEMS-Based Solid Propellant Rocket Array Thruster

    Science.gov (United States)

    Tanaka, Shuji; Hosokawa, Ryuichiro; Tokudome, Shin-Ichiro; Hori, Keiichi; Saito, Hirobumi; Watanabe, Masashi; Esashi, Masayoshi

    The prototype of a solid propellant rocket array thruster for simple attitude control of a 10 kg class micro-spacecraft was completed and tested. The prototype has 10×10 φ0.8 mm solid propellant micro-rockets arrayed at a pitch of 1.2 mm on a 20×22 mm substrate. To realize such a dense array of micro-rockets, each ignition heater is powered from the backside of the thruster through an electrical feedthrough which passes along a propellant cylinder wall. Boron/potassium nitrate propellant (NAB) is used with/without lead rhodanide/potassium chlorate/nitrocellulose ignition aid (RK). Impulse thrust was measured by a pendulum method in air. Ignition required electric power of at least 3 4 W with RK and 4 6 W without RK. Measured impulse thrusts were from 2×10-5 Ns to 3×10-4 Ns after the calculation of compensation for air dumping.

  9. Weight savings in aerospace vehicles through propellant scavenging

    Science.gov (United States)

    Schneider, Steven J.; Reed, Brian D.

    1988-01-01

    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. Modeling and Fault Simulation of Propellant Filling System

    International Nuclear Information System (INIS)

    Jiang Yunchun; Liu Weidong; Hou Xiaobo

    2012-01-01

    Propellant filling system is one of the key ground plants in launching site of rocket that use liquid propellant. There is an urgent demand for ensuring and improving its reliability and safety, and there is no doubt that Failure Mode Effect Analysis (FMEA) is a good approach to meet it. Driven by the request to get more fault information for FMEA, and because of the high expense of propellant filling, in this paper, the working process of the propellant filling system in fault condition was studied by simulating based on AMESim. Firstly, based on analyzing its structure and function, the filling system was modular decomposed, and the mathematic models of every module were given, based on which the whole filling system was modeled in AMESim. Secondly, a general method of fault injecting into dynamic system was proposed, and as an example, two typical faults - leakage and blockage - were injected into the model of filling system, based on which one can get two fault models in AMESim. After that, fault simulation was processed and the dynamic characteristics of several key parameters were analyzed under fault conditions. The results show that the model can simulate effectively the two faults, and can be used to provide guidance for the filling system maintain and amelioration.

  11. Guidelines Manual: Post Accident Procedures for Chemicals and Propellants.

    Science.gov (United States)

    1983-01-01

    verification cloud. On the other hand, the risks of materials on-scene. Also, a diaper - associated with evacuation of the sive IR instrument and portable...of direction, cloud cover and solar the 28 chemicals and propellants in this radiation level; study. The Chemical Hazard Slide Rule Is relatively easy

  12. 30 CFR 56.4230 - Self-propelled equipment.

    Science.gov (United States)

    2010-07-01

    ....4230 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Fire Prevention and Control Firefighting Equipment § 56.4230 Self-propelled equipment. (a)(1) Whenever a fire or its effects...

  13. 30 CFR 57.4230 - Surface self-propelled equipment.

    Science.gov (United States)

    2010-07-01

    ... Section 57.4230 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire... fire or its effects could impede escape from self-propelled equipment, a fire extinguisher shall be on...

  14. 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

  15. 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.

  16. Self-propelled pulse X-ray apparatus Sirena-1

    International Nuclear Information System (INIS)

    Danil'chenko, N.T.; Ershov, L.S.; Il'chenko, A.V.; Krasil'nikov, S.B.; Kristalinskij, A.L.; Lozovoj, L.N.; Markov, S.N.; Morgovskij, L.Ya.

    1984-01-01

    The structure and specifications of a self-propelled pulse X-ray apparatus ''Sirena-1'' for testing oilt and gas pipelines welded joints are described. The apparatus is designed on the base of pulse X-ray apparatus MIRA. Apparatus control is realized by means of the 137 Cs source or manual control desk. The apparatus ensures perfect control sensitivity

  17. Composite materials design and applications

    CERN Document Server

    Gay, Daniel; Tsai, Stephen W

    2002-01-01

    PART ONE. PRINCIPLES OF CONSTRUCTIONCOMPOSITE MATERIALS, INTEREST AND PROPERTIESWhat is Composite Material Fibers and MatrixWhat can be Made Using Composite Materials?Typical Examples of Interest on the Use of Composite MaterialsExamples on Replacing Conventional Solutions with CompositesPrincipal Physical PropertiesFABRICATION PROCESSESMolding ProcessesOther Forming ProcessesPractical Hints in the Manufacturing ProcessesPLY PROPERTIESIsotropy and AnisotropyCharacteristics of the Reinforcement-Matrix MixtureUnidirectional PlyWoven FabricsMats and Reinforced MatricesMultidimensional FabricsMetal Matrix CompositesTestsSANDWICH STRUCTURES:What is a Sandwich Structure?Simplified FlexureA Few Special AspectsFabrication and Design ProblemsNondestructive Quality ControlCONCEPTION AND DESIGNDesign of a Composite PieceThe LaminateFailure of LaminatesSizing of LaminatesJOINING AND ASSEMBLYRiveting and BoltingBondingInsertsCOMPOSITE MATERIALS AND AEROSPACE CONSTRUCTIONAircraftHelicoptersPropeller Blades for AirplanesTur...

  18. Influence of material anisotropy on the hydroelastic response of composite plates in water

    Science.gov (United States)

    Akcabay, Deniz Tolga; Young, Yin Lu

    2018-03-01

    Flexible lightweight plate-like lifting surfaces in external flows have a diverse range of use from propelling and controlling marine and aerospace vehicles to converting wind and ocean energy to electrical energy. Design and analysis of such structures are complex for underwater applications where the water density is much higher than air. The hydrodynamic loads, which vary with the inflow speed, can significantly alter the dynamic response and stability. This paper focuses on the hydroelastic response of composite plates in water. The results show that the dynamics and stability of the structure can be significantly modified by taking advantage of the material anisotropic; on the contrary, careless composite material designs may lead to unwanted dynamic instability failures. The resonance frequencies, divergence speeds, and fluid loss coefficients change with material anisotropy and hydrodynamic loads. The resonance frequencies are much lower in water than in air. The critical divergence speed increases, if the principal fiber direction is oriented towards the inflow. Hydrodynamic damping is shown to be much higher than the material damping, and tend to increase with flow speed and to decrease with increasing modal frequency. The paper derives Response Amplitude Operators (RAOs) for sample composite plates in water and use them to predict the motion response when subject to stochastic flow excitations. We show how material anisotropy can be used to passively tailor the plate vibration response spectrum to limit or enhance flow-induced vibrations of the plate depending on the desired applications.

  19. Advanced composites: Design and application. Proceedings of the meeting of the Mechanical Failures Prevention Group

    Science.gov (United States)

    Shives, T. R.; Willard, W. A.

    1979-01-01

    The design and application of advanced composites is discussed with emphasis on aerospace, aircraft, automotive, marine, and industrial applications. Failure modes in advanced composites are also discussed.

  20. Marine animal stings or bites

    Science.gov (United States)

    Stings - marine animals; Bites - marine animals ... Things you can do to prevent a marine animal sting or bite include: Swim near a lifeguard. Observe posted signs that may warn of danger from jellyfish or other hazardous marine life. ...

  1. Mariners Weather Log

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Mariners Weather Log (MWL) is a publication containing articles, news and information about marine weather events and phenomena, worldwide environmental impact...

  2. MarineCadastre.gov

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MarineCadastre.gov is a marine information system that provides authoritative ocean data, offshore planning tools, and technical support to the offshore renewable...

  3. Marine Jurisdiction Boundaries

    Data.gov (United States)

    Department of Homeland Security — The NOAA Coastal Services Center's Marine Jurisdiction dataset was created to assist in marine spatial planning and offshore alternative energy sitting. This is a...

  4. Tsunamis and marine life

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, D.V.S.; Ingole, B.S.; Tang, D.; Satyanarayan, B.; Zhao, H.

    The 26 December 2004 tsunami in the Indian Ocean exerted far reaching temporal and spatial impacts on marine biota. Our synthesis was based on satellite data acquired by the Laboratory for Tropical Marine Environmental Dynamics (LED) of the South...

  5. Supermarket Marine Biology.

    Science.gov (United States)

    Colby, Jennifer A.; And Others

    1995-01-01

    Describes a survey used to determine the availability of intact marine vertebrates and live invertebrates in supermarkets. Results shows that local supermarkets frequently provide a variety of intact marine organisms suitable for demonstrations, experiments, or dissections. (ZWH)

  6. Seashore marine table quiz

    OpenAIRE

    Institute, Marine

    2013-01-01

    Develop an increasing awareness of plants and animals that live in local marine environments including the seashore, seas and oceans of Ireland. After learning all about the seashore and other marine related lessons, this quiz can be used to evaluate the student’s knowledge of the marine related living things and natural environments. The table quiz can be used as a guide, highlighting facts about the marine environment and some of the animals that live there.

  7. Carotenoids in Marine Animals

    OpenAIRE

    Maoka, Takashi

    2011-01-01

    Marine animals contain various carotenoids that show structural diversity. These marine animals accumulate carotenoids from foods such as algae and other animals and modify them through metabolic reactions. Many of the carotenoids present in marine animals are metabolites of β-carotene, fucoxanthin, peridinin, diatoxanthin, alloxanthin, and astaxanthin, etc. Carotenoids found in these animals provide the food chain as well as metabolic pathways. In the present review, I will describe marine a...

  8. Weak Compliance Undermines the Success of No-Take Zones in a Large Government-Controlled Marine Protected Area

    KAUST Repository

    Campbell, Stuart J.; Hoey, Andrew; Maynard, Jeffrey; Kartawijaya, Tasrif; Cinner, Joshua; Graham, Nicholas A. J.; Baird, Andrew H.

    2012-01-01

    The effectiveness of marine protected areas depends largely on whether people comply with the rules. We quantified temporal changes in benthic composition, reef fish biomass, and fishing effort among marine park zones (including no-take areas

  9. 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...... 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...... 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...

  10. 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.

  11. 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.

  12. 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.

  13. Study of the pitting effects during the pre-ignition plasma–propellant interaction process

    International Nuclear Information System (INIS)

    Hang, Yuhua; Li, Xingwen; Wu, Jian; Jia, Shenli; Zhao, Weiyu; Murphy, Anthony B

    2016-01-01

    The propellant ignition mechanism has become a central issue in the electrothermal chemical (ETC) launch technology, and the pre-ignition plasma–propellant interactions are critical in determining the ignition characteristics. In this work, both an open-air ablation test and an interrupted burning test are conducted for three different propellants. A fused silica window, which is transparent in all relevant wavelengths, is utilized to investigate the role of the plasma radiation. Surface pitting of the propellants after interaction with the plasma is analyzed using a scanning electron microscope (SEM). The effect of pits on the plasma ignition is then studied and a possible formation mechanism of pits is proposed. The input heat flux and the surface temperature of the propellants are obtained by solving a pre-ignition plasma–propellant interaction model. The results shed light on the pre-ignition plasma ignition mechanisms and will assist in the development of propellants for an ETC launcher. (paper)

  14. Marine Education Knowledge Inventory.

    Science.gov (United States)

    Hounshell, Paul B.; Hampton, Carolyn

    This 35-item, multiple-choice Marine Education Knowledge Inventory was developed for use in upper elementary/middle schools to measure a student's knowledge of marine science. Content of test items is drawn from oceanography, ecology, earth science, navigation, and the biological sciences (focusing on marine animals). Steps in the construction of…

  15. Marine polar steroids

    International Nuclear Information System (INIS)

    Stonik, Valentin A

    2001-01-01

    Structures, taxonomic distribution and biological activities of polar steroids isolated from various marine organisms over the last 8-10 years are considered. The peculiarities of steroid biogenesis in the marine biota and their possible biological functions are discussed. Syntheses of some highly active marine polar steroids are described. The bibliography includes 254 references.

  16. A Nordic approach to impact assessment of accidents with nuclear-propelled vessels

    International Nuclear Information System (INIS)

    Reistad, O.; Hustveit, S.; Palsson, S.E.; Hoe, S.; Lahtinen, J.

    2012-11-01

    The MareNuc project has identified the parameters in a graded approach to impact assessment for marine nuclear reactors. The graded approach is founded on the following elements: 1) More detailed understanding of previous accidents in nuclear-propelled vessels (initiating events, accident developments, release fractions), including release mechanisms (radionuclide retention in vessel construction); 2) Bench-marking of release scenarios using modelling tools applied in the Nordic countries, in addition to demonstration of generally accessible and free software developed by the IAEA; 3) Other systematic approaches to safety assessments of vessel port calls, and to the design and maintenance of emergency preparedness systems; More specifically, increased emphasis compared to earlier analysis after the Kursk accident is given to the engineered vessel barriers. Relevant standards from impact assessments for commercial nuclear power plants have been identified, such as from the NUREG series. The Nordic approaches to safety evaluation, impact assessments and emergency preparedness organisation was also reported as part of the project. The Canadian approach for international port calls was carefully reported and assessed as part of the project, and commended for its broad and comprehensive approach to reactor and vessel design for the nationalities involved, to the design and maintenance of emergency preparedness systems, and the well-structured and broad cooperation between civilian and military institutions. This approach goes beyond the current approach in the Nordic countries, also in the case of Norway, which experience regular port calls from allied nuclear navies. The overall result is a broader understanding in the Nordic countries for the importance of the various parameters for impact assessment of releases from marine reactors, and to the design and maintenance of an emergency preparedness organisation without detailed knowledge of the installation in question

  17. A Nordic approach to impact assessment of accidents with nuclear-propelled vessels

    Energy Technology Data Exchange (ETDEWEB)

    Reistad, O. [Institute for Energy Technology, Kjeller (Norway); Hustveit, S. [Norwegian Radiation Protection Authority, Oesteraes (Norway); Palsson, S.E. [Icelandic Radiation Safety Authority, Reykjavik (Iceland); Hoe, S. [Danish Emergency Management Agency, Birkeroed (Denmark); Lahtinen, J. [STUK, Helsinki (Finland)

    2012-11-15

    The MareNuc project has identified the parameters in a graded approach to impact assessment for marine nuclear reactors. The graded approach is founded on the following elements: 1) More detailed understanding of previous accidents in nuclear-propelled vessels (initiating events, accident developments, release fractions), including release mechanisms (radionuclide retention in vessel construction); 2) Bench-marking of release scenarios using modelling tools applied in the Nordic countries, in addition to demonstration of generally accessible and free software developed by the IAEA; 3) Other systematic approaches to safety assessments of vessel port calls, and to the design and maintenance of emergency preparedness systems; More specifically, increased emphasis compared to earlier analysis after the Kursk accident is given to the engineered vessel barriers. Relevant standards from impact assessments for commercial nuclear power plants have been identified, such as from the NUREG series. The Nordic approaches to safety evaluation, impact assessments and emergency preparedness organisation was also reported as part of the project. The Canadian approach for international port calls was carefully reported and assessed as part of the project, and commended for its broad and comprehensive approach to reactor and vessel design for the nationalities involved, to the design and maintenance of emergency preparedness systems, and the well-structured and broad cooperation between civilian and military institutions. This approach goes beyond the current approach in the Nordic countries, also in the case of Norway, which experience regular port calls from allied nuclear navies. The overall result is a broader understanding in the Nordic countries for the importance of the various parameters for impact assessment of releases from marine reactors, and to the design and maintenance of an emergency preparedness organisation without detailed knowledge of the installation in question

  18. Marine nitrogen cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    ) such as the Marine nitrogen cycle The marine nitrogen cycle. ‘X’ and ‘Y’ are intra-cellular intermediates that do not accumulate in water column. (Source: Codispoti et al., 2001) Page 1 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www... and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 85-105, 2001. Page 2 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www.eoearth.org/article/Marine_nitrogen_cycle square6 Gruber, N.: The dynamics...

  19. Carotenoids in Marine Animals

    Science.gov (United States)

    Maoka, Takashi

    2011-01-01

    Marine animals contain various carotenoids that show structural diversity. These marine animals accumulate carotenoids from foods such as algae and other animals and modify them through metabolic reactions. Many of the carotenoids present in marine animals are metabolites of β-carotene, fucoxanthin, peridinin, diatoxanthin, alloxanthin, and astaxanthin, etc. Carotenoids found in these animals provide the food chain as well as metabolic pathways. In the present review, I will describe marine animal carotenoids from natural product chemistry, metabolism, food chain, and chemosystematic viewpoints, and also describe new structural carotenoids isolated from marine animals over the last decade. PMID:21566799

  20. Monitoring the magnitude of marine vessel infestation by non-indigenous ascidians in the Mediterranean.

    Science.gov (United States)

    Gewing, Mey-Tal; Shenkar, Noa

    2017-08-15

    Invasive ascidians (Chordata, Tunicata) are dominant nuisance organisms. The current study investigated the role of marine vessels in their dispersal and introduction. An examination of 45 dry-docked marine vessels, comprising recreational, commercial, and military craft, in five Israeli shipyards along the Mediterranean coast, revealed non-indigenous ascidians (NIA) on every second vessel investigated. Military vessels featured the highest ascidian abundance and richness, potentially related to their maintenance routine. Niche areas on the vessels such as sea chests and the propeller exhibited the highest occurrence of ascidians. Overall, these findings provide strong evidence that marine vessels play an acute role in NIA introduction and dispersal, with military vessels and niche areas on all the vessels being more susceptible to serving as vectors. A discovery of a new introduced species during the surveys suggests that the monitoring of marine vessels can serve as an effective tool for the early detection of NIA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. 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.

  2. Nano and micro architectures for self-propelled motors

    International Nuclear Information System (INIS)

    Parmar, Jemish; Ma, Xing; Katuri, Jaideep; Simmchen, Juliane; Stanton, Morgan M; Trichet-Paredes, Carolina; Soler, Lluís; Sanchez, Samuel

    2015-01-01

    Self-propelled micromotors are emerging as important tools that help us understand the fundamentals of motion at the microscale and the nanoscale. Development of the motors for various biomedical and environmental applications is being pursued. Multiple fabrication methods can be used to construct the geometries of different sizes of motors. Here, we present an overview of appropriate methods of fabrication according to both size and shape requirements and the concept of guiding the catalytic motors within the confines of wall. Micromotors have also been incorporated with biological systems for a new type of fabrication method for bioinspired hybrid motors using three-dimensional (3D) printing technology. The 3D printed hybrid and bioinspired motors can be propelled by using ultrasound or live cells, offering a more biocompatible approach when compared to traditional catalytic motors. (focus issue paper)

  3. Homogenization Issues in the Combustion of Heterogeneous Solid Propellants

    Science.gov (United States)

    Chen, M.; Buckmaster, J.; Jackson, T. L.; Massa, L.

    2002-01-01

    We examine random packs of discs or spheres, models for ammonium-perchlorate-in-binder propellants, and discuss their average properties. An analytical strategy is described for calculating the mean or effective heat conduction coefficient in terms of the heat conduction coefficients of the individual components, and the results are verified by comparison with those of direct numerical simulations (dns) for both 2-D (disc) and 3-D (sphere) packs across which a temperature difference is applied. Similarly, when the surface regression speed of each component is related to the surface temperature via a simple Arrhenius law, an analytical strategy is developed for calculating an effective Arrhenius law for the combination, and these results are verified using dns in which a uniform heat flux is applied to the pack surface, causing it to regress. These results are needed for homogenization strategies necessary for fully integrated 2-D or 3-D simulations of heterogeneous propellant combustion.

  4. Vertical-axis turbine/propeller for ship propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Barkla, H.M.

    1984-01-01

    There are so many variables in the design and operating conditions of a vertical-axis turbine/propeller for the propulsion of a ship by wind that a preliminary study is offered, based on two simplified models. Study of a linear motion of blades in air and water shows optimum conditions for blade-speed and blade-incidence. Analysis of the second, cyclical model is simplified by the assumption of constant angles of incidence. While the logical superiority of the vertical-axis system, with its low transmission loss, may not alone give it the advantage over all other systems in upwind and downwind sailing, there are indications that in the beam wind it is in a class of its own; the Voith-Schneider-Type propeller then produces a thrust with a major component to windward, so that the combined unit leaves little or no athwartships force.

  5. Self-regulation in self-propelled nematic fluids.

    Science.gov (United States)

    Baskaran, A; Marchetti, M C

    2012-09-01

    We consider the hydrodynamic theory of an active fluid of self-propelled particles with nematic aligning interactions. This class of materials has polar symmetry at the microscopic level, but forms macrostates of nematic symmetry. We highlight three key features of the dynamics. First, as in polar active fluids, the control parameter for the order-disorder transition, namely the density, is dynamically convected by the order parameter via active currents. The resulting dynamical self-regulation of the order parameter is a generic property of active fluids and destabilizes the uniform nematic state near the mean-field transition. Secondly, curvature-driven currents render the system unstable deep in the nematic state, as found previously. Finally, and unique to self-propelled nematics, nematic order induces local polar order that in turn leads to the growth of density fluctuations. We propose this as a possible mechanism for the smectic order of polar clusters seen in numerical simulations.

  6. Propellant Feed System for Swirl-Coaxial Injection

    Science.gov (United States)

    Reynolds, David Christopher (Inventor)

    2015-01-01

    A propellant feed system for swirl-coaxial injection of a liquid propellant includes a reservoir having a bottom plate and at least one tube originating in the bottom plate and extending therefrom. The tube has rectangular slits defined in and distributed tangentially and evenly about a portion of the tube that is disposed in the bottom plate. Drain holes are provided in the bottom plate and tunnels are defined in the bottom plate. Each tunnel fluidly couples one of the drain holes to a corresponding one of the rectangular slits. Each tunnel includes (i) a bend of at least 90.degree., and (ii) a straight portion leading to its corresponding rectangular slit wherein the straight portion is at least five times as long as a hydraulic diameter of the corresponding rectangular slit.

  7. 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

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

    Science.gov (United States)

    2016-11-01

    Measuring ener- getic contaminant deposition rates on snow. Water Air Soil Pollut (2012) 223:3689–3699. [25] Rasemann, W (2000) Industrial waste...the system off the ground, providing both clearance from most combustible materials or snow that may lie beneath it while partially containing the...ergetic compounds in the propellant charges. This mass was measured outside the pan, as the most important component of the residues is what is

  9. Propeller rotation noise due to torque and thrust

    Science.gov (United States)

    Deming, Arthur F

    1940-01-01

    Sound pressure of the first four harmonics of rotation from a full-scale two-blade propeller were measured and are compared with values calculated from theory. The comparison is made (1) for the space distribution with constant tip speed and (2) for fixed space angles with variable tip speed. A relation for rotation noise from an element of radius developed by Gutin is given showing the effect of number of blades on the rotation noise.

  10. Driving dynamic colloidal assembly using eccentric self-propelled colloids

    OpenAIRE

    Ma, Zhan; Lei, Qun-li; Ni, Ran

    2017-01-01

    Designing protocols to dynamically direct the self-assembly of colloidal particles has become an important direction in soft matter physics because of the promising applications in fabrication of dynamic responsive functional materials. Here using computer simulations, we found that in the mixture of passive colloids and eccentric self-propelled active particles, when the eccentricity and self-propulsion of active particles are high enough, the eccentric active particles can push passive coll...

  11. 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 ...

  12. Low-Cost Propellant Launch From a Tethered Balloon

    Science.gov (United States)

    Wilcox, Brian

    2006-01-01

    A document presents a concept for relatively inexpensive delivery of propellant to a large fuel depot in low orbit around the Earth, for use in rockets destined for higher orbits, the Moon, and for remote planets. The propellant is expected to be at least 85 percent of the mass needed in low Earth orbit to support the NASA Exploration Vision. The concept calls for the use of many small ( 10 ton) spin-stabilized, multistage, solid-fuel rockets to each deliver 250 kg of propellant. Each rocket would be winched up to a balloon tethered above most of the atmospheric mass (optimal altitude 26 2 km). There, the rocket would be aimed slightly above the horizon, spun, dropped, and fired at a time chosen so that the rocket would arrive in orbit near the depot. Small thrusters on the payload (powered, for example, by boil-off gases from cryogenic propellants that make up the payload) would precess the spinning rocket, using data from a low-cost inertial sensor to correct for small aerodynamic and solid rocket nozzle misalignment torques on the spinning rocket; would manage the angle of attack and the final orbit insertion burn; and would be fired on command from the depot in response to observations of the trajectory of the payload so as to make small corrections to bring the payload into a rendezvous orbit and despin it for capture by the depot. The system is low-cost because the small rockets can be mass-produced using the same techniques as those to produce automobiles and low-cost munitions, and one or more can be launched from a U.S. territory on the equator (Baker or Jarvis Islands in the mid-Pacific) to the fuel depot on each orbit (every 90 minutes, e.g., any multiple of 6,000 per year).

  13. An Experimental and Theoretical Study on Cavitating Propellers.

    Science.gov (United States)

    1982-10-01

    34 And Identfyp eV &to" nMeeJ cascade flow theoretical supercavitating flow performance prediction method partially cavitating flow supercavitating ...the present work was to develop an analytical tool for predicting the off-design performance of supercavitating propellers over a wide range of...operating conditions. Due to the complex nature of the flow phenomena, a lifting line theory sirply combined with the two-dimensional supercavitating

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

    Science.gov (United States)

    2007-10-01

    and ellipsoids, and the packing of pellets relevant to igniter modeling. Other topics are the instabilities of smolder waves, premixed flame...instabilities in narrow tubes, and flames supported by a spinning porous plug burner . Much of this work has been reported in the high-quality archival...perchlorate in fuel binder, the combustion of model propellant packs of ellipses and ellipsoids, and the packing of pellets relevant to igniter modeling

  15. Marine Robot Autonomy

    CERN Document Server

    2013-01-01

    Autonomy for Marine Robots provides a timely and insightful overview of intelligent autonomy in marine robots. A brief history of this emerging field is provided, along with a discussion of the challenges unique to the underwater environment and their impact on the level of intelligent autonomy required.  Topics covered at length examine advanced frameworks, path-planning, fault tolerance, machine learning, and cooperation as relevant to marine robots that need intelligent autonomy.  This book also: Discusses and offers solutions for the unique challenges presented by more complex missions and the dynamic underwater environment when operating autonomous marine robots Includes case studies that demonstrate intelligent autonomy in marine robots to perform underwater simultaneous localization and mapping  Autonomy for Marine Robots is an ideal book for researchers and engineers interested in the field of marine robots.      

  16. 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.

  17. Advanced Solar-propelled Cargo Spacecraft for Mars Missions

    Science.gov (United States)

    Auziasdeturenne, Jacqueline; Beall, Mark; Burianek, Joseph; Cinniger, Anna; Dunmire, Barbrina; Haberman, Eric; Iwamoto, James; Johnson, Stephen; Mccracken, Shawn; Miller, Melanie

    1989-01-01

    Three concepts for an unmanned, solar powered, cargo spacecraft for Mars support missions were investigated. These spacecraft are designed to carry a 50,000 kg payload from a low Earth orbit to a low Mars orbit. Each design uses a distinctly different propulsion system: A Solar Radiation Absorption (SRA) system, a Solar-Pumped Laser (SPL) system and a solar powered magnetoplasmadynamic (MPD) arc system. The SRA directly converts solar energy to thermal energy in the propellant through a novel process. In the SPL system, a pair of solar-pumped, multi-megawatt, CO2 lasers in sunsynchronous Earth orbit converts solar energy to laser energy. The MPD system used indium phosphide solar cells to convert sunlight to electricity, which powers the propulsion system. Various orbital transfer options are examined for these concepts. In the SRA system, the mother ship transfers the payload into a very high Earth orbit and a small auxiliary propulsion system boosts the payload into a Hohmann transfer to Mars. The SPL spacecraft and the SPL powered spacecraft return to Earth for subsequent missions. The MPD propelled spacecraft, however, remains at Mars as an orbiting space station. A patched conic approximation was used to determine a heliocentric interplanetary transfer orbit for the MPD propelled spacecraft. All three solar-powered spacecraft use an aerobrake procedure to place the payload into a low Mars parking orbit. The payload delivery times range from 160 days to 873 days (2.39 years).

  18. Formulation and properties of ADN/GAP propellants

    Energy Technology Data Exchange (ETDEWEB)

    Menke, Klaus; Heintz, Thomas; Schweikert, Wenka; Keicher, Thomas; Krause, Horst [Fraunhofer-Institut fuer Chemische Technologie ICT, Pfinztal (Germany)

    2009-06-15

    In this contribution two ways are described, how it is possible to achieve perfectly cured and processible propellants with prilled ADN, low amounts of HMX 5{mu}m mps and a binder system based on GAP diole and GAP triole oligomers with and without TMETN as a nitrate ester plasticizer. It was shown how it will be possible to suppress the strongly gas forming reaction between ADN and reactive isocyanates by a mixture of stabilizers. In this way it was possible to create minimum smoke ADN/HMX/GAP/TMETN propellants cured with the triisocyanate N100. In the second part an unconventional binder system based on the 1.3 dipolar cycloaddition reaction of azido groups with acetylene compounds forming 1,2,3-triazole heterocyclic rings has been applied for ADN/GAP and AP/GAP propellants. Together with small parts of HMX formulations with ADN/HMX/GAP and the corresponding AP/HMX/GAP exhibit high thermodynamic performance, are easily processible, and cure successfully at 60 C. Their basic properties consisting of burning behavior and mechanical properties, at ambient temperature, chemical stability, and sensitivity have been investigated and are compared to each other. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  19. Self-Propelled Micromotors for Cleaning Polluted Water

    Science.gov (United States)

    2013-01-01

    We describe the use of catalytically self-propelled microjets (dubbed micromotors) for degrading organic pollutants in water via the Fenton oxidation process. The tubular micromotors are composed of rolled-up functional nanomembranes consisting of Fe/Pt bilayers. The micromotors contain double functionality within their architecture, i.e., the inner Pt for the self-propulsion and the outer Fe for the in situ generation of ferrous ions boosting the remediation of contaminated water.The degradation of organic pollutants takes place in the presence of hydrogen peroxide, which acts as a reagent for the Fenton reaction and as main fuel to propel the micromotors. Factors influencing the efficiency of the Fenton oxidation process, including thickness of the Fe layer, pH, and concentration of hydrogen peroxide, are investigated. The ability of these catalytically self-propelled micromotors to improve intermixing in liquids results in the removal of organic pollutants ca. 12 times faster than when the Fenton oxidation process is carried out without catalytically active micromotors. The enhanced reaction–diffusion provided by micromotors has been theoretically modeled. The synergy between the internal and external functionalities of the micromotors, without the need of further functionalization, results into an enhanced degradation of nonbiodegradable and dangerous organic pollutants at small-scale environments and holds considerable promise for the remediation of contaminated water. PMID:24180623

  20. Working-cycle processes in solid-propellant rocket engines (Handbook). Rabochie protsessy v raketnykh dvigateliakh tverdogo topliva /Spravochnik/

    Energy Technology Data Exchange (ETDEWEB)

    Shishkov, A.A.; Panin, S.D.; Rumiantsev, B.V.

    1989-01-01

    Physical and mathematical models of processes taking place in solid-propellant rocket engines and gas generators are presented in a systematic manner. The discussion covers the main types of solid propellants, the general design and principal components of solid-propellant rocket engines, the combustion of a solid-propellant charge, thermodynamic calculation of combustion and outflow processes, and analysis of gasdynamic processes in solid-propellant rocket engines. 40 refs.