In vitro study of 3D PLGA/n-HAp/β-TCP composite scaffolds with etched oxygen plasma surface modification in bone tissue engineering

NASA Astrophysics Data System (ADS)

Roh, Hee-Sang; Jung, Sang-Chul; Kook, Min-Suk; Kim, Byung-Hoon

2016-12-01

Three-dimensional (3D) scaffolds have many advantageous properties for bone tissue engineering application, due to its controllable properties such as pore size, structural shape and interconnectivity. In this study, effects on oxygen plasma surface modification and adding of nano-hydroxyapatite (n-HAp) and β-tricalcium phosphate (β-TCP) on the 3D PLGA/n-HAp/β-TCP scaffolds for improving preosteoblast cell (MC3T3-E1) adhesion, proliferation and differentiation were investigated. The 3D PLGA/n-HAp/β-TCP scaffolds were fabricated by 3D Bio-Extruder equipment. The 3D scaffolds were prepared with 0°/90° architecture and pore size of approximately 300 μm. In addition 3D scaffolds surface were etched by oxygen plasma to enhance the hydrophilic property and surface roughness. After oxygen plasma treatment, the surface chemistry and morphology were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. And also hydrophilic property was measured by contact angle. The MC3T3-E1 cell proliferation and differentiation were investigated by MTT assay and ALP activity. In present work, the 3D PLGA/HAp/beta-TCP composite scaffold with suitable structure for the growth of osteoblast cells was successfully fabricated by 3D rapid prototyping technique. The surface hydrophilicity and roughness of 3D scaffold increased by oxygen plasma treatment had a positive effect on cell adhesion, proliferation, and differentiation. Furthermore, the differentiation of MC3T3-E1 cell was significantly enhanced by adding of n-HAp and β-TCP on 3D PLGA scaffold. As a result, combination of bioceramics and oxygen plasma treatment showed a synergistic effect on biocompatibility of 3D scaffolds. This result confirms that this technique was useful tool for improving the biocompatibility in bone tissue engineering application.

Particle based plasma simulation for an ion engine discharge chamber

NASA Astrophysics Data System (ADS)

Mahalingam, Sudhakar

Design of the next generation of ion engines can benefit from detailed computer simulations of the plasma in the discharge chamber. In this work a complete particle based approach has been taken to model the discharge chamber plasma. This is the first time that simplifying continuum assumptions on the particle motion have not been made in a discharge chamber model. Because of the long mean free paths of the particles in the discharge chamber continuum models are questionable. The PIC-MCC model developed in this work tracks following particles: neutrals, singly charged ions, doubly charged ions, secondary electrons, and primary electrons. The trajectories of these particles are determined using the Newton-Lorentz's equation of motion including the effects of magnetic and electric fields. Particle collisions are determined using an MCC statistical technique. A large number of collision processes and particle wall interactions are included in the model. The magnetic fields produced by the permanent magnets are determined using Maxwell's equations. The electric fields are determined using an approximate input electric field coupled with a dynamic determination of the electric fields caused by the charged particles. In this work inclusion of the dynamic electric field calculation is made possible by using an inflated plasma permittivity value in the Poisson solver. This allows dynamic electric field calculation with minimal computational requirements in terms of both computer memory and run time. In addition, a number of other numerical procedures such as parallel processing have been implemented to shorten the computational time. The primary results are those modeling the discharge chamber of NASA's NSTAR ion engine at its full operating power. Convergence of numerical results such as total number of particles inside the discharge chamber, average energy of the plasma particles, discharge current, beam current and beam efficiency are obtained. Steady state results for

Lightweight Portable Plasma Medical Device - Plasma Engineering Research Laboratory

DTIC Science & Technology

2014-10-01

34Optical study of radicals (OH, O, H, N) in a needle- plate negative pulsed streamer corona discharge ," Plasma Chemistry and Plasma Processing, vol. 26...pulsed corona discharge ," European Physical Journal D, vol. 38, pp. 515-522, Jun 2006. [35] W. Wang, S. Wang, F. Liu, W. Zheng, and D. Wang, "Optical...study of OH radical in a wire-plate pulsed corona discharge ," Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 63, pp. 477

Combining platelet-rich plasma and tissue-engineered skin in the treatment of large skin wound.

PubMed

Han, Tong; Wang, Hao; Zhang, Ya Qin

2012-03-01

The objective of the study was to observe the effects of tissue-engineered skin in combination with platelet-rich plasma (PRP) and other preparations on the repair of large skin wound on nude mice.We first prepared PRP from venous blood by density-gradient centrifugation. Large skin wounds were created surgically on the dorsal part of nude mice. The wounds were then treated with either artificial skin, tissue-engineered skin, tissue-engineered skin combined with basic fibroblast growth factor, tissue-engineered skin combined with epidermal growth factor, or tissue-engineered skin combined with PRP. Tissue specimens were collected at different time intervals after surgery. Hematoxylin-eosin and periodic acid-Schiff staining and immunohistochemistry were performed to assess the rate of wound healing.Macroscopic observations, hematoxylin-eosin/periodic acid-Schiff staining, and immunohistochemistry revealed that the wounds treated with tissue-engineered skin in combination with PRP showed the most satisfactory wound recovery, among the 5 groups.

Supersonic plasma beams with controlled speed generated by the alternative low power hybrid ion engine (ALPHIE) for space propulsion

NASA Astrophysics Data System (ADS)

Conde, L.; Domenech-Garret, J. L.; Donoso, J. M.; Damba, J.; Tierno, S. P.; Alamillo-Gamboa, E.; Castillo, M. A.

2017-12-01

The characteristics of supersonic ion beams from the alternative low power hybrid ion engine (ALPHIE) are discussed. This simple concept of a DC powered plasma accelerator that only needs one electron source for both neutral gas ionization and ion beam neutralization is also examined. The plasma production and space charge neutralization processes are thus coupled in this plasma thruster that has a total DC power consumption of below 450 W, and uses xenon or argon gas as a propellant. The operation parameters of the plasma engine are studied in the laboratory in connection with the ion energy distribution function obtained with a retarding-field energy analyzer. The ALPHIE plasma beam expansion produces a mesothermal plasma flow with two-peaked ion energy distribution functions composed of low and high speed ion groups. The characteristic drift velocities of the fast ion groups, in the range 36.6-43.5 Km/s, are controlled by the acceleration voltage. These supersonic speeds are higher than the typical ion sound velocities of the low energy ion group produced by the expansion of the plasma jet. The temperatures of the slow ion population lead to ion Debye lengths longer than the electron Debye lengths. Furthermore, the electron impact ionization can coexist with collisional ionization by fast ions downstream the grids. Finally, the performance characteristics and comparisons with other plasma accelerator schemes are also discussed.

Laboratory and Space Plasma Studies

NASA Astrophysics Data System (ADS)

Hyman, Ellis

1996-08-01

The work performed by Science Applications International Corporation (SAIC), encompasses a wide range of topics in experimental, computational, and analytical laboratory and space plasma physics. The accomplishments described in this report have been in support of the programs of the Laser Plasma Branch (Code 6730) and other segments of the Plasma Physics Division at the Naval Research Laboratory (NRL) and cover the period 27 September 1993 to August 1, 1996. SAIC's efforts have been supported by sub-contracts or consulting agreements with Pulse Sciences, Inc., Clark Richardson, and Biskup Consulting Engineers, Pharos Technical Enterprises, Plex Corporation, Cornell University, Stevens Institute of Technology, the University of Connecticut, Plasma Materials and Technologies, Inc., and GaSonics International, Inc. In the following discussions section we will describe each of the topics investigated and the results obtained. Much of the research work has resulted in journal publications and NRL Memorandum Reports in which the investigation is described in detail. These reports are included as Appendices to this Final Report.

DBD Plasma Actuators for Flow Control in Air Vehicles and Jet Engines - Simulation of Flight Conditions in Test Chambers by Density Matching

NASA Technical Reports Server (NTRS)

Ashpis, David E.; Thurman, Douglas R.

2011-01-01

Dielectric Barrier Discharge (DBD) Plasma actuators for active flow control in aircraft and jet engines need to be tested in the laboratory to characterize their performance at flight operating conditions. DBD plasma actuators generate a wall-jet electronically by creating weakly ionized plasma, therefore their performance is affected by gas discharge properties, which, in turn, depend on the pressure and temperature at the actuator placement location. Characterization of actuators is initially performed in a laboratory chamber without external flow. The pressure and temperature at the actuator flight operation conditions need to be simultaneously set in the chamber. A simplified approach is desired. It is assumed that the plasma discharge depends only on the gas density, while other temperature effects are assumed to be negligible. Therefore, tests can be performed at room temperature with chamber pressure set to yield the same density as in operating flight conditions. The needed chamber pressures are shown for altitude flight of an air vehicle and for jet engines at sea-level takeoff and altitude cruise conditions. Atmospheric flight conditions are calculated from standard atmosphere with and without shock waves. The engine data was obtained from four generic engine models; 300-, 150-, and 50-passenger (PAX) aircraft engines, and a military jet-fighter engine. The static and total pressure, temperature, and density distributions along the engine were calculated for sea-level takeoff and for altitude cruise conditions. The corresponding chamber pressures needed to test the actuators were calculated. The results show that, to simulate engine component flows at in-flight conditions, plasma actuator should be tested over a wide range of pressures. For the four model engines the range is from 12.4 to 0.03 atm, depending on the placement of the actuator in the engine. For example, if a DBD plasma actuator is to be placed at the compressor exit of a 300 PAX engine, it

Perspective of laser-induced plasma ignition of hydrocarbon fuel in Scramjet engine

NASA Astrophysics Data System (ADS)

Yang, Leichao; Li, Xiaohui; Liang, Jianhan; Yu, Xin; Li, Xipeng

2016-01-01

Laser-induced plasma ignition of an ethylene fuelled cavity was successfully conducted in a model scramjet engine combustor. The ethylene was injected 10mm upstream of cavity flameholder from 3 orifices 60 degree inclined relative to freestream direction. The 1064nm laser beam, from a Q-switched Nd:YAG laser source running at 3Hz and 200mJ per pulse, was focused into cavity for ignition. High speed photography was used to capture the transient ignition process. The laser-induced gas breakdown, flame kernel generation and propagation were all recorded and ensuing stable supersonic combustion was established in cavity. The flame kernel is found rotating anti-clockwise and gradually moves upwards as the entrainment of circulation flow in cavity. The flame is then stretched from leading edge to trailing edge to fully fill the entire cavity. Eventually, a stable combustion is achieved roughly 900μs after the laser pulse. The results show promising potentials for practical application. The perspective of laser-induced plasma ignition of hydrocarbon fuel in scramjet engine is outlined.

The CPS Plasma Award at the Intel Science and Engineering Fair

NASA Astrophysics Data System (ADS)

Berry, Lee

2012-10-01

For the past eight years, the Coalition for Plasma Science (CPS) has presented an award for a plasma project at the Intel International Science and Engineering Fair (ISEF). We reported on the first five years of this award at the 2009 DPP Symposium. Pulsed neutron-producing experiments are a recurring topic, with the efforts now turning to applications. The most recent award at the Pittsburgh ISEF this past May was given for analysis of data from Brookhaven's Relativistic Heavy Ion Collider. The effort had the goal of understanding the fluid properties of the quark-gluon plasma. All of the CPS award-winning projects so far have been based on experiments, with four awards going to women students and four to men. In 2009 we noted that the number and quality of projects was improving. Since then, as we we predicted (hoped for), that trend has continued. The CPS looks forward to continuing its work with students who are excited about the possibilities of plasma. You too can share this excitement by judging at the 2013 fair in Phoenix on May 12-17. Information may be obtained by emailing cps@plasmacoalition.org.

Experimental investigations of a uranium plasma pertinent to a self-sustaining plasma source

NASA Technical Reports Server (NTRS)

Schneider, R. T.

1971-01-01

The research is pertinent to the realization of a self-sustained fissioning plasma for applications such as nuclear propulsion, closed cycle MHD power generation using a plasma core reactor, and heat engines such as the nuclear piston engine, as well as the direct conversion of fission energy into optical radiation (nuclear pumped lasers). Diagnostic measurement methods and experimental devices simulating plasma core reactor conditions are discussed. Studies on the following topics are considered: (1) ballistic piston compressor (U-235); (2) high pressure uranium plasma (natural uranium); (3) sliding spark discharge (natural uranium); (4) fission fragment interaction (He-3 and U-235); and (5) nuclear pumped lasers (He-3 and U-235).

The Plasma Archipelago: Plasma Physics in the 1960s

NASA Astrophysics Data System (ADS)

Weisel, Gary J.

2017-09-01

With the foundation of the Division of Plasma Physics of the American Physical Society in April 1959, plasma physics was presented as the general study of ionized gases. This paper investigates the degree to which plasma physics, during its first decade, established a community of interrelated specialties, one that brought together work in gaseous electronics, astrophysics, controlled thermonuclear fusion, space science, and aerospace engineering. It finds that, in some regards, the plasma community was indeed greater than the sum of its parts and that its larger identity was sometimes glimpsed in inter-specialty work and studies of fundamental plasma behaviors. Nevertheless, the plasma specialties usually worked separately for two inter-related reasons: prejudices about what constituted "basic physics," both in the general physics community and within the plasma community itself; and a compartmentalized funding structure, in which each funding agency served different missions.

Spectroscopic Studies of Laser Produced Plasma Metasurfaces

NASA Astrophysics Data System (ADS)

Colon Quinones, Roberto; Underwood, Thomas; Cappelli, Mark

2016-10-01

In this presentation, we describe the spatial and temporal plasma characteristics of the dense plasma kernels that are used to construct a laser produced plasma metasurface (PM) that is intended to serve as a tunable THz reflector. The PM is an n x n array of plasmas generated by focusing the light from a 2 J/p Q-switched Nd:YAG laser through a multi-lens array (MLA) and into a gas of varying pressure. A gated CCD camera coupled to a high-resolution spectrometer is used to obtain chord-averaged H α broadening data for the cross section of a single plasma element at the lens focal point. The data is then Abel inverted to derive the radial plasma density distribution. Measurements are repeated for a range of pressures, laser energies, and lens f-number, with a time resolution of 100 ns and a gate width of 20 ns. Results are presented for the variation of plasma density and size over these different conditions. Work supported by the Air Force Office of Scientific Research (AFOSR). R. Colon Quinones and T. Underwood acknowledge the support of the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

Effect of plasma spraying modes on material properties of internal combustion engine cylinder liners

NASA Astrophysics Data System (ADS)

Timokhova, O. M.; Burmistrova, O. N.; Sirina, E. A.; Timokhov, R. S.

2018-03-01

The paper analyses different methods of remanufacturing worn-out machine parts in order to get the best performance characteristics. One of the most promising of them is a plasma spraying method. The mathematical models presented in the paper are intended to anticipate the results of plasma spraying, its effect on the properties of the material of internal combustion engine cylinder liners under repair. The experimental data and research results have been computer processed with Statistica 10.0 software package. The pare correlation coefficient values (R) and F-statistic criterion are given to confirm the statistical properties and adequacy of obtained regression equations.

Characterization of the human plasma phosphoproteome using linear ion trap mass spectrometry and multiple search engines.

PubMed

Carrascal, Montserrat; Gay, Marina; Ovelleiro, David; Casas, Vanessa; Gelpí, Emilio; Abian, Joaquin

2010-02-05

Major plasma protein families play different roles in blood physiology and hemostasis and in immunodefense. Other proteins in plasma can be involved in signaling as chemical messengers or constitute biological markers of the status of distant tissues. In this respect, the plasma phosphoproteome holds potentially relevant information on the mechanisms modulating these processes through the regulation of protein activity. In this work we describe for the first time a collection of phosphopeptides identified in human plasma using immunoaffinity separation of the seven major serum protein families from other plasma proteins, SCX fractionation, and TiO(2) purification prior to LC-MS/MS analysis. One-hundred and twenty-seven phosphosites in 138 phosphopeptides mapping 70 phosphoproteins were identified with FDR < 1%. A high-confidence collection of phosphosites was obtained using a combined search with the OMSSA, SEQUEST, and Phenyx search engines.

Automated Plasma Spray (APS) process feasibility study: Plasma spray process development and evaluation

NASA Technical Reports Server (NTRS)

Fetheroff, C. W.; Derkacs, T.; Matay, I. M.

1979-01-01

An automated plasma spray (APS) process was developed to apply two layer (NiCrAlY and ZrO2-12Y2O3) thermal-barrier coatings to aircraft gas turbine engine blade airfoils. The APS process hardware consists of four subsystems: a mechanical blade positioner incorporating two interlaced six-degree-of-freedom assemblies; a noncoherent optical metrology subsystem; a microprocessor-based adaptive system controller; and commercial plasma spray equipment. Over fifty JT9D first stage turbine blades specimens were coated with the APS process in preliminary checkout and evaluation studies. The best of the preliminary specimens achieved an overall coating thickness uniformity of + or - 53 micrometers, much better than is achievable manually. Factors limiting this performance were identified and process modifications were initiated accordingly. Comparative evaluations of coating thickness uniformity for manually sprayed and APS coated specimens were initiated. One of the preliminary evaluation specimens was subjected to a torch test and metallographic evaluation.

Non-thermal plasma for exhaust gases treatment

NASA Astrophysics Data System (ADS)

Alva R., Elvia; Pacheco P., Marquidia; Gómez B., Fernando; Pacheco P., Joel; Colín C., Arturo; Sánchez-Mendieta, Víctor; Valdivia B., Ricardo; Santana D., Alfredo; Huertas C., José; Frías P., Hilda

2015-09-01

This article describes a study on a non-thermal plasma device to treat exhaust gases in an internal combustion engine. Several tests using a plasma device to treat exhaust gases are conducted on a Honda GX200-196 cm3 engine at different rotational speeds. A plasma reactor could be efficient in degrading nitrogen oxides and particulate matter. Monoxide and carbon dioxide treatment is minimal. However, achieving 1%-3% degradation may be interesting to reduce the emission of greenhouse gases.

A novel gate and drain engineered charge plasma tunnel field-effect transistor for low sub-threshold swing and ambipolar nature

NASA Astrophysics Data System (ADS)

Yadav, Dharmendra Singh; Raad, Bhagwan Ram; Sharma, Dheeraj

2016-12-01

In this paper, we focus on the improvement of figures of merit for charge plasma based tunnel field-effect transistor (TFET) in terms of ON-state current, threshold voltage, sub-threshold swing, ambipolar nature, and gate to drain capacitance which provides better channel controlling of the device with improved high frequency response at ultra-low supply voltages. Regarding this, we simultaneously employ work function engineering on the drain and gate electrode of the charge plasma TFET. The use of gate work function engineering modulates the barrier on the source/channel interface leads to improvement in the ON-state current, threshold voltage, and sub-threshold swing. Apart from this, for the first time use of work function engineering on the drain electrode increases the tunneling barrier for the flow of holes on the drain/channel interface, it results into suppression of ambipolar behavior. The lowering of gate to drain capacitance therefore enhanced high frequency parameters. Whereas, the presence of dual work functionality at the gate electrode and over the drain region improves the overall performance of the charge plasma based TFET.

Opportunities for Utilizing the International Space Station for Studies of F2- Region Plasma Science and High Voltage Solar Array Interactions with the Plasma Environment

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Coffey, Victoria; Wright, Kenneth; Craven, Paul; Koontz, Steven

2010-01-01

The near circular, 51.6deg inclination orbit of the International Space Station (ISS) is maintained within an altitude range of approximately 300 km to 400 km providing an ideal platform for conducting in-situ studies of space weather effects on the mid and low-latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) is a suite of instruments installed on the ISS in August 2006 which includes a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep Langmuir Probe (WLP), and a Narrow-sweep Langmuir Probe (NLP). The primary purpose for deploying the FPMU is to characterize ambient plasma temperatures and densities in which the ISS operates and to obtain measurements of the ISS potential relative to the space plasma environment for use in characterizing and mitigating spacecraft charging hazards to the vehicle and crew. In addition to the engineering goals, data from the FPMU instrument package is available for collaborative multi-satellite and ground based instrument studies of the F-region ionosphere during both quiet and disturbed periods. Finally, the FPMU measurements supported by ISS engineering telemetry data provides a unique opportunity to investigate interactions of the ISS high voltage (160 volt) solar array system with the plasma environment. This presentation will provide examples of FPMU measurements along the ISS orbit including night-time equatorial plasma density depletions sampled near the peak electron density in the F2-region ionosphere, charging phenomenon due to interaction of the ISS solar arrays with the plasma environment, and modification of ISS charging due to visiting vehicles demonstrating the capabilities of the FPMU probes for monitoring mid and low latitude plasma processes as well as vehicle interactions with the plasma environment.

An investigation of the treatment of particulate matter from gasoline engine exhaust using non-thermal plasma.

PubMed

Ye, Dan; Gao, Dengshan; Yu, Gang; Shen, Xianglin; Gu, Fan

2005-12-09

A plasma reactor with catalysts was used to treat exhaust gas from a gasoline engine in order to decrease particulate matter (PM) emissions. The effect of non-thermal plasma (NTP) of the dielectric discharges on the removal of PM from the exhaust gas was investigated experimentally. The removal efficiency of PM was based on the concentration difference in PM for particle diameters ranging from 0.3 to 5.0 microm as measured by a particle counter. Several factors affecting PM conversion, including the density of plasma energy, reaction temperature, flow rate of exhaust gas, were investigated in the experiment. The results indicate that PM removal efficiency ranged approximately from 25 to 57% and increased with increasing energy input in the reactor, reaction temperature and residence time of the exhaust gas in the reactor. Enhanced removal of the PM was achieved by filling the discharge gap of the reactor with Cu-ZSM-5 catalyst pellets. In addition, the removal of unburned hydrocarbons was studied. Finally, available approaches for PM conversion were analyzed involving the interactions between discharge and catalytic reactions.

Lightweight Portable Plasma Medical Device - Plasma Engineering Research Laboratory

DTIC Science & Technology

2015-12-01

Wang, W. Zheng, and Y. N. Wang, "Optical study of radicals (OH, O, H, N) in a needle-plate negative pulsed streamer corona discharge ," Plasma...needle- plate bi-directional pulsed corona discharge ," European Physical Journal D, vol. 38, pp. 515-522, Jun 2006. 155 [35] W. Wang, S. Wang...F. Liu, W. Zheng, and D. Wang, "Optical study of OH radical in a wire-plate pulsed corona discharge ," Spectrochimica Acta Part A: Molecular and

Pulsed Plasma Processing of Diesel Engine Exhaust Final Report CRADA No. TC-0336-92-1-C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merritt, Bernard T.; Broering, Louis

The goal was to develop an exhaust-gas treatment process for the reduction of NO x and hydrocarbon from diesel engines. The project began believing that direct chemical reduction on NO x was possible through the use of non-thermal plasmas. The original CRADA began in 1993 and was scheduled to finish in 1996. It had as its goals three metrics: 1) remove two grams/brake-horse-power-hour of NOx, 2) have no more than five percent energy penalty, and 3) cost no more than ten percent of the engine cost. These goals were all aimed at heavy-duty diesel trucks. This CRADA had its Defensemore » Program funding eliminated by DOE prior to completion in 1995. Prior to loss of funding from DOE, LLNL discovered that due to the large oxygen content in diesel exhaust, direct chemical reduction was not possible. In understanding why, a breakthrough was achieved that combined the use of a non-thermal plasma and a catalyst. This process was named Plasma Assisted Catalytic Reduction (P ACR). Because of this breakthrough, the CRADA became a funds-in only CRADA, once DOE DP funding ended. As a result, the funding decreased from about 1M dollars per year to about $400k per year. Subsequently, progress slowed as well. The CRADA was amended several times to reflect the funds-in nature. At each amendment, the deliverables were modified; the goals remained the same but the focus changed from heavy-duty to lightduty to SUVs. The diesel-engine NO x problem is similar to the furnace and boiler NO x emission problem with the added constraint that ammonia-like additives are impractical for a mobile source. Lean-burning gasoline engines are an additional area of application because the standard three-way catalyst is rendered ineffective by the presence of oxygen. In the P ACR process an electrical discharge is used to create a non-thermal plasma that contains oxidative radicals O and OH. These oxidative radicals convert NO to NO 2. Selective catalytic reduction using a readily available catalyst

Control of magnetohydrodynamic stability by phase space engineering of energetic ions in tokamak plasmas.

PubMed

Graves, J P; Chapman, I T; Coda, S; Lennholm, M; Albergante, M; Jucker, M

2012-01-10

Virtually collisionless magnetic mirror-trapped energetic ion populations often partially stabilize internally driven magnetohydrodynamic disturbances in the magnetosphere and in toroidal laboratory plasma devices such as the tokamak. This results in less frequent but dangerously enlarged plasma reorganization. Unique to the toroidal magnetic configuration are confined 'circulating' energetic particles that are not mirror trapped. Here we show that a newly discovered effect from hybrid kinetic-magnetohydrodynamic theory has been exploited in sophisticated phase space engineering techniques for controlling stability in the tokamak. These theoretical predictions have been confirmed, and the technique successfully applied in the Joint European Torus. Manipulation of auxiliary ion heating systems can create an asymmetry in the distribution of energetic circulating ions in the velocity orientated along magnetic field lines. We show the first experiments in which large sawtooth collapses have been controlled by this technique, and neoclassical tearing modes avoided, in high-performance reactor-relevant plasmas.

[Fundamentals of plasma chemistry and its application to drug engineering].

PubMed

Kuzuya, M

1996-04-01

In this review, our novel research works in both low temperature plasma chemistry and solid state plasma chemistry were described. As for low temperature plasma, the ESR study on plasma-induced radicals of several selected conventional polymers was shown including the detailed analyses of the radical structure and the mechanism by which the radicals were formed on typical degradable methacrylic polymers and cross-linkable polystyrene. One of the pharmaceutical applications of the plasma processing for drug delivery system (DDS) was also described, which includes the preparations of double-compressed tablet consisting of drugs as a core material and various types of polymers as a wall material followed by plasma-irradiation on such a tablet. As for solid state plasma, the detailed reaction mechanism of solid state mechanochemical polymerization was shown including the solid state single electron transfer and the special feature of the resulting polymers. The structural criteria for polymerizable monomer derived from the quantum chemical considerations were also established. Based on the above findings, we synthesized various polymeric prodrugs by mechanochemical polymerization and studied the nature of hydrolyses (drug release).

Study of Plasma Liner Driven Magnetized Target Fusion Via Advanced Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samulyak, Roman V.; Brookhaven National Lab.; Parks, Paul

The feasibility of the plasma liner driven Magnetized Target Fusion (MTF) via terascale numerical simulations will be assessed. In the MTF concept, a plasma liner, formed by merging of a number (60 or more) of radial, highly supersonic plasma jets, implodes on the target in the form of two compact plasma toroids, and compresses it to conditions of the fusion ignition. By avoiding major difficulties associated with both the traditional laser driven inertial confinement fusion and solid liner driven MTF, the plasma liner driven MTF potentially provides a low-cost and fast R&D path towards the demonstration of practical fusion energy.more » High fidelity numerical simulations of full nonlinear models associated with the plasma liner MTF using state-of-art numerical algorithms and terascale computing are necessary in order to resolve uncertainties and provide guidance for future experiments. At Stony Brook University, we have developed unique computational capabilities that ideally suite the MTF problem. The FronTier code, developed in collaboration with BNL and LANL under DOE funding including SciDAC for the simulation of 3D multi-material hydro and MHD flows, has beenbenchmarked and used for fundamental and engineering problems in energy science applications. We have performed 3D simulations of converging supersonic plasma jets, their merger and the formation of the plasma liner, and a study of the corresponding oblique shock problem. We have studied the implosion of the plasma liner on the magnetized plasma target by resolving Rayleigh-Taylor instabilities in 2D and 3D and other relevant physics and estimate thermodynamic conditions of the target at the moment of maximum compression and the hydrodynamic efficiency of the method.« less

Plasma-wall interaction studies within the EUROfusion consortium: progress on plasma-facing components development and qualification

NASA Astrophysics Data System (ADS)

Brezinsek, S.; Coenen, J. W.; Schwarz-Selinger, T.; Schmid, K.; Kirschner, A.; Hakola, A.; Tabares, F. L.; van der Meiden, H. J.; Mayoral, M.-L.; Reinhart, M.; Tsitrone, E.; Ahlgren, T.; Aints, M.; Airila, M.; Almaviva, S.; Alves, E.; Angot, T.; Anita, V.; Arredondo Parra, R.; Aumayr, F.; Balden, M.; Bauer, J.; Ben Yaala, M.; Berger, B. M.; Bisson, R.; Björkas, C.; Bogdanovic Radovic, I.; Borodin, D.; Bucalossi, J.; Butikova, J.; Butoi, B.; Čadež, I.; Caniello, R.; Caneve, L.; Cartry, G.; Catarino, N.; Čekada, M.; Ciraolo, G.; Ciupinski, L.; Colao, F.; Corre, Y.; Costin, C.; Craciunescu, T.; Cremona, A.; De Angeli, M.; de Castro, A.; Dejarnac, R.; Dellasega, D.; Dinca, P.; Dittmar, T.; Dobrea, C.; Hansen, P.; Drenik, A.; Eich, T.; Elgeti, S.; Falie, D.; Fedorczak, N.; Ferro, Y.; Fornal, T.; Fortuna-Zalesna, E.; Gao, L.; Gasior, P.; Gherendi, M.; Ghezzi, F.; Gosar, Ž.; Greuner, H.; Grigore, E.; Grisolia, C.; Groth, M.; Gruca, M.; Grzonka, J.; Gunn, J. P.; Hassouni, K.; Heinola, K.; Höschen, T.; Huber, S.; Jacob, W.; Jepu, I.; Jiang, X.; Jogi, I.; Kaiser, A.; Karhunen, J.; Kelemen, M.; Köppen, M.; Koslowski, H. R.; Kreter, A.; Kubkowska, M.; Laan, M.; Laguardia, L.; Lahtinen, A.; Lasa, A.; Lazic, V.; Lemahieu, N.; Likonen, J.; Linke, J.; Litnovsky, A.; Linsmeier, Ch.; Loewenhoff, T.; Lungu, C.; Lungu, M.; Maddaluno, G.; Maier, H.; Makkonen, T.; Manhard, A.; Marandet, Y.; Markelj, S.; Marot, L.; Martin, C.; Martin-Rojo, A. B.; Martynova, Y.; Mateus, R.; Matveev, D.; Mayer, M.; Meisl, G.; Mellet, N.; Michau, A.; Miettunen, J.; Möller, S.; Morgan, T. W.; Mougenot, J.; Mozetič, M.; Nemanič, V.; Neu, R.; Nordlund, K.; Oberkofler, M.; Oyarzabal, E.; Panjan, M.; Pardanaud, C.; Paris, P.; Passoni, M.; Pegourie, B.; Pelicon, P.; Petersson, P.; Piip, K.; Pintsuk, G.; Pompilian, G. O.; Popa, G.; Porosnicu, C.; Primc, G.; Probst, M.; Räisänen, J.; Rasinski, M.; Ratynskaia, S.; Reiser, D.; Ricci, D.; Richou, M.; Riesch, J.; Riva, G.; Rosinski, M.; Roubin, P.; Rubel, M.; Ruset, C.; Safi, E.; Sergienko, G.; Siketic, Z.; Sima, A.; Spilker, B.; Stadlmayr, R.; Steudel, I.; Ström, P.; Tadic, T.; Tafalla, D.; Tale, I.; Terentyev, D.; Terra, A.; Tiron, V.; Tiseanu, I.; Tolias, P.; Tskhakaya, D.; Uccello, A.; Unterberg, B.; Uytdenhoven, I.; Vassallo, E.; Vavpetič, P.; Veis, P.; Velicu, I. L.; Vernimmen, J. W. M.; Voitkans, A.; von Toussaint, U.; Weckmann, A.; Wirtz, M.; Založnik, A.; Zaplotnik, R.; PFC contributors, WP

2017-11-01

The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma-material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W

Quiet engine program flight engine design study

NASA Technical Reports Server (NTRS)

Klapproth, J. F.; Neitzel, R. E.; Seeley, C. T.

1974-01-01

The results are presented of a preliminary flight engine design study based on the Quiet Engine Program high-bypass, low-noise turbofan engines. Engine configurations, weight, noise characteristics, and performance over a range of flight conditions typical of a subsonic transport aircraft were considered. High and low tip speed engines in various acoustically treated nacelle configurations were included.

Plasma Processing with a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP)

NASA Astrophysics Data System (ADS)

Reece Roth, J.

2000-10-01

The vast majority of all industrial plasma processing is conducted with glow discharges at pressures below 10 torr. This has limited applications to high value workpieces as a result of the large capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharges would play a much larger industrial role if they could be operated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) has been developed at the University of Tennessee Plasma Sciences Laboratory. The OAUGDP is non-thermal RF plasma with the time-resolved characteristics of a classical low pressure DC normal glow discharge. An interdisciplinary team was formed to conduct exploratory investigations of the physics and applications of the OAUGDP. This team includes collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC) and the Departments of Electrical and Computer Engineering, Microbiology, Food Science and Technology, and Mechanical and Aerospace Engineering and Engineering Science. Exploratory tests were conducted on a variety of potential plasma processing and other applications. These include the use of OAUGDP to sterilize medical and dental equipment and air filters; diesel soot removal; plasma aerodynamic effects; electrohydrodynamic (EDH) flow control of the neutral working gas; increasing the surface energy of materials; increasing the wettability and wickability of fabrics; and plasma deposition and directional etching. A general overview of these topics will be presented.

Rotorcraft convertible engine study

NASA Technical Reports Server (NTRS)

Gill, J. C.; Earle, R. V.; Mar, H. M.

1982-01-01

The objective of the Rotorcraft Convertible Engine Study was to define future research and technology effort required for commercial development by 1988 of convertible fan/shaft gas turbine engines for unconventional rotorcraft transports. Two rotorcraft and their respective missions were defined: a Fold Tilt Rotor aircraft and an Advancing Blade Concept (ABC) rotorcraft. Sensitivity studies were conducted with these rotorcraft to determine parametrically the influence of propulsion characteristics on aircraft size, mission fuel requirements, and direct operating costs (DOC). The two rotorcraft were flown with conventional propulsion systems (separate lift/cruise engines) and with convertible propulsion systems to determine the benefits to be derived from convertible engines. Trade-off studies were conducted to determine the optimum engine cycle and staging arrangement for a convertible engine. Advanced technology options applicable to convertible engines were studied. Research and technology programs were identified which would ensure technology readiness for commercial development of convertible engines by 1988.

Orbit transfer rocket engine technology program: Advanced engine study

NASA Technical Reports Server (NTRS)

Erickson, C. M.

1992-01-01

In Task D.6 of the Advanced Engine Study, three primary subtasks were accomplished: (1) design of parametric data; (2) engine requirement variation studies; and (3) vehicle study/engine study coordination. Parametric data were generated for vacuum thrusts ranging from 7500 lbf to 50,000 lbf, nozzle expansion ratios from 600 to 1200, and engine mixture ratios from 5:1 to 7:1. Failure Modes and Effects Analysis (FMEA) was used as a departure point for these parametric analyses. These data are intended to assist in definition and trade studies. In the Engine Requirements Variation Studies, the individual effects of increasing the throttling ratio from 10:1 to 20:1 and requiring the engine to operate at a maximum mixture ratio of 12:1 were determined. Off design engine balances were generated at these extreme conditions and individual component operating requirements analyzed in detail. Potential problems were identified and possible solutions generated. In the Vehicle Study/Engine Study coordination subtask, vehicle contractor support was provided as needed, addressing a variety of issues uncovered during vehicle trade studies. This support was primarily provided during Technical Interchange Meetings (TIM) in which Space Exploration Initiative (SEI) studies were addressed.

Development of super-clean diesel engine and combustor using nonthermal plasma hybrid aftertreatment

NASA Astrophysics Data System (ADS)

Okubo, Masaaki

2015-10-01

One of important and successful environmental applications of atmospheric-pressure corona discharge or plasma is electrostatic precipitator (ESP), which have been widely used for coal- or oil-fired boilers in electric power plants and particulate matter control emitted from industries such as glass melting furnace system, etc. In the ESPs, steady high voltage is usually applied to a pair of electrodes (at least, one of these has sharp edge). Unsteady pulsed high voltage is often applied for the collection of high-resistivity particulate matter (PM) to avoid reverse corona phenomena which reduce the collection efficiency of the ESPs. It was found that unsteady high voltage can treat hazardous gaseous components (NOx, SOx, hydrocarbon, and CO, etc.) in the exhaust gas, and researches were shifted from PM removal to hazardous gases aftertreatment with unsteady corona discharge induced plasmas. In the paper, recent results on diesel engine and industrial boiler emission controls are mainly reviewed among these our research topics.

Plasma-assisted interface engineering of boron nitride nanostructure films.

PubMed

Pakdel, Amir; Bando, Yoshio; Golberg, Dmitri

2014-10-28

Today many aspects of science and technology are progressing into the nanoscale realm where surfaces and interfaces are intrinsically important in determining properties and performances of materials and devices. One familiar phenomenon in which interfacial interactions play a major role is the wetting of solids. In this work we use a facile one-step plasma method to control the wettability of boron nitride (BN) nanostructure films via covalent chemical functionalization, while their surface morphology remains intact. By tailoring the concentration of grafted hydroxyl groups, superhydrophilic, hydrophilic, and hydrophobic patterns are created on the initially superhydrophobic BN nanosheet and nanotube films. Moreover, by introducing a gradient of the functional groups, directional liquid spreading toward increasing [OH] content is achieved on the films. The resulting insights are meant to illustrate great potentials of this method to tailor wettability of ceramic films, control liquid flow patterns for engineering applications such as microfluidics and biosensing, and improve the interfacial contact and adhesion in nanocomposite materials.

A numerical study of neutral-plasma interaction in magnetically confined plasmas

NASA Astrophysics Data System (ADS)

Taheri, S.; Shumlak, U.; King, J. R.

2017-10-01

Interactions between plasma and neutral species can have a large effect on the dynamic behavior of magnetically confined plasma devices, such as the edge region of tokamaks and the plasma formation of Z-pinches. The presence of neutrals can affect the stability of the pinch and change the dynamics of the pinch collapse, and they can lead to deposition of high energy particles on the first wall. However, plasma-neutral interactions can also have beneficial effects such as quenching the disruptions in tokamaks. In this research a reacting plasma-neutral model, which combines a magnetohydrodynamic (MHD) plasma model with a gas dynamic neutral fluid model, is used to study the interaction between plasma and neutral gas. Incorporating this model into NIMROD allows the study of electron-impact ionization, radiative recombination, and resonant charge-exchange in plasma-neutral systems. An accelerated plasma moving through a neutral gas background is modeled in both a parallel plate and a coaxial electrode configuration to explore the effect of neutral gas in pinch-like devices. This work is supported by a Grant from US DOE.

Plasma Processes for Semiconductor Fabrication

NASA Astrophysics Data System (ADS)

Hitchon, W. N. G.

1999-01-01

Plasma processing is a central technique in the fabrication of semiconductor devices. This self-contained book provides an up-to-date description of plasma etching and deposition in semiconductor fabrication. It presents the basic physics and chemistry of these processes, and shows how they can be accurately modeled. The author begins with an overview of plasma reactors and discusses the various models for understanding plasma processes. He then covers plasma chemistry, addressing the effects of different chemicals on the features being etched. Having presented the relevant background material, he then describes in detail the modeling of complex plasma systems, with reference to experimental results. The book closes with a useful glossary of technical terms. No prior knowledge of plasma physics is assumed in the book. It contains many homework exercises and serves as an ideal introduction to plasma processing and technology for graduate students of electrical engineering and materials science. It will also be a useful reference for practicing engineers in the semiconductor industry.

Incorporating Platelet-Rich Plasma into Electrospun Scaffolds for Tissue Engineering Applications

PubMed Central

Wolfe, Patricia S.; Ericksen, Jeffery J.; Simpson, David G.; Bowlin, Gary L.

2011-01-01

Platelet-rich plasma (PRP) therapy has seen a recent spike in clinical interest due to the potential that the highly concentrated platelet solutions hold for stimulating tissue repair and regeneration. The aim of this study was to incorporate PRP into a number of electrospun materials to determine how growth factors are eluted from the structures, and what effect the presence of these factors has on enhancing electrospun scaffold bioactivity. PRP underwent a freeze-thaw-freeze process to lyse platelets, followed by lyophilization to create a powdered preparation rich in growth factors (PRGF), which was subsequently added to the electrospinning process. Release of protein from scaffolds over time was quantified, along with the quantification of human macrophage and adipose-derived stem cell (ADSC) chemotaxis and proliferation. Protein assays demonstrated a sustained release of protein from PRGF-containing scaffolds at up to 35 days in culture. Scaffold bioactivity was enhanced as ADSCs demonstrated increased proliferation in the presence of PRGF, whereas macrophages demonstrated increased chemotaxis to PRGF. In conclusion, the work performed in this study demonstrated that the incorporation of PRGF into electrospun structures has a significant positive influence on the bioactivity of the scaffolds, and may prove beneficial in a number of tissue engineering applications. PMID:21679135

Ultra-efficient Engine Diameter Study

NASA Technical Reports Server (NTRS)

Daggett, David L.; Brown, Stephen T.; Kawai, Ron T.

2003-01-01

Engine fan diameter and Bypass Ratio (BPR) optimization studies have been conducted since the beginning of the turbofan age with the recognition that reducing the engine core jet velocity and increasing fan mass flow rate generally increases propulsive efficiency. However, performance tradeoffs limit the amount of fan flow achievable without reducing airplane efficiency. This study identifies the optimum engine fan diameter and BPR, given the advanced Ultra-Efficient Engine Technology (UEET) powerplant efficiencies, for use on an advanced subsonic airframe. Engine diameter studies have historically focused on specific engine size options, and were limited by existing technology and transportation infrastructure (e.g., ability to fit bare engines through aircraft doors and into cargo holds). This study is unique in defining the optimum fan diameter and drivers for future 2015 (UEET) powerplants while not limiting engine fan diameter by external constraints. This report follows on to a study identifying the system integration issues of UEET engines. This Engine Diameter study was managed by Boeing Phantom Works, Seattle, Washington through the NASA Glenn Revolutionary Aero Space Engine Research (RASER) contract under task order 10. Boeing Phantom Works, Huntington Beach, completed the engine/airplane sizing optimization, while the Boeing Commercial Airplane group (BCA) provided design oversight. A separate subcontract to support the overall project was issued to Tuskegee University.

Electrostatic Plasma Accelerator (EPA)

NASA Technical Reports Server (NTRS)

Brophy, John R.; Aston, Graeme

1989-01-01

The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass. The goal of the present program is to demonstrate feasibility of the EPA thruster concept through experimental and theoretical investigations of the EPA acceleration mechanism and discharge chamber performance. Experimental investigations will include operating the test bed ion (TBI) engine as an EPA thruster and parametrically varying the thruster geometry and operating conditions to quantify the electrostatic plasma acceleration effect. The theoretical investigations will include the development of a discharge chamber model which describes the relationships between the engine size, plasma properties, and overall performance. For the EPA thruster to be a viable propulsion concept, overall thruster efficiencies approaching 30% with specific impulses approaching 1000 s must be achieved.

Development of TPF-1 plasma focus for education

NASA Astrophysics Data System (ADS)

Picha, R.; Promping, J.; Channuie, J.; Poolyarat, N.; Sangaroon, S.; Traikool, T.

2017-09-01

The plasma focus is a device that uses high voltage and electromagnetic force to induce plasma generation and acceleration, in order to cause nuclear reactions. Radiation of various types (X-ray, gamma ray, electrons, ions, neutrons) can be generated using this method during the pinch phase, thus making the plasma focus able to serve as a radiation source. Material testing, modification, and identification are among the current applications of the plasma focus. Other than being an alternative option to isotopic sources, the plasma focus, which requires multidisciplinary team of personnel to design, operate, and troubleshoot, can also serve as an excellent learning device for physics and engineering students in the fields including, but not limited to, plasma physics, nuclear physics, electronics engineering, and mechanical engineering. This work describes the parameters and current status of Thai Plasma Focus 1 (TPF-1) and the characteristics of the plasma being produced in the machine using a Rogowski coil.

Platelet-rich plasma combined with agarose as a bioactive scaffold to enhance cartilage repair: an in vitro study.

PubMed

Yin, Zhaowei; Yang, Xiaofei; Jiang, Yiqiu; Xing, Linzi; Xu, Yang; Lu, Yiming; Ding, Peng; Ma, Junxin; Xu, Yan; Gui, Jianchao

2014-03-01

The purpose of this study was to determine whether the platelet-rich plasma-agarose gel scaffold could be a bioactive scaffold capable of growth factors release for cartilage repair. Porcine chondrocytes were seeded in agarose gel and platelet-rich plasma-agarose gel. During the 28-days culture, microstructure of hydrogels and morphologies of chondrocytes seeded in the hydrogels were observed using scanning electron microscope; viability of chondrocytes in gels was examined by live/dead assay; qualitative and quantitative analysis of glycosaminoglycan, collagen and DNA were assessed by histological, immunohistochemical staining and biochemical assay; gene expression was measured by real-time polymerase chain reaction. In vitro cartilage ring models were used to evaluate the integration of the scaffolds, and the integration strength was analyzed by mechanical push-out tests. Scanning electron microscope revealed both scaffolds had highly uniform porous structure. Live/dead scaffolds showed 100% cells alive in both groups. After 28-days culture, glycosaminoglycan, collagen, DNA content and chondrocyte-related genes expression in platelet-rich plasma-agarose gel were significantly higher than pure agarose gel. Integration strength in platelet-rich plasma-agarose gel was also higher compared to pure agarose gel. Platelet-rich plasma showed a positive effect on chondrocytes proliferation, differentiation and integration between native cartilage and engineered tissue when combined with agarose gel. Our findings suggest that platelet-rich plasma-agarose gel scaffold is a promising bioactive scaffold for future cartilage tissue engineering and future clinical works.

Near Discharge Cathode Assembly Plasma Potential Measurements in a 30-cm NSTAR Type Ion Engine During Beam Extraction

NASA Technical Reports Server (NTRS)

Herman, Daniel A.; Gallimore, Alec D.

2006-01-01

Floating emissive probe plasma potential data are presented over a two-dimensional array of locations in the near Discharge Cathode Assembly (DCA) region of a 30-cm diameter ring-cusp ion thruster. Discharge plasma data are presented with beam extraction at throttling conditions comparable to the NASA TH Levels 8, 12, and 15. The operating conditions of the Extended Life Test (ELT) of the Deep Space One (DS1) flight spare ion engine, where anomalous discharge keeper erosion occurred, were TH 8 and TH 12 consequently they are of specific interest in investigating discharge keeper erosion phenomena. The data do not validate the presence of a potential hill plasma structure downstream of the DCA, which has been proposed as a possible erosion mechanism. The data are comparable in magnitude to data taken by other researchers in ring-cusp electron-bombardment ion thrusters. The plasma potential structures are insensitive to thruster throttling level with a minimum as low as 14 V measured at the DCA exit plane and increasing gradually in the axial direction. A sharp increase in plasma potential to the bulk discharge value of 26 to 28 volts, roughly 10 mm radially from DCA centerline, was observed. Plasma potential measurements indicate a low-potential plume structure that is roughly 20 mm in diameter emanating from the discharge cathode that may be attributed to a free-standing plasma double layer.

Effect of indirect non-thermal plasma on particle size distribution and composition of diesel engine particles

NASA Astrophysics Data System (ADS)

Linbo, GU; Yixi, CAI; Yunxi, SHI; Jing, WANG; Xiaoyu, PU; Jing, TIAN; Runlin, FAN

2017-11-01

To explore the effect of the gas source flow rate on the actual diesel exhaust particulate matter (PM), a test bench for diesel engine exhaust purification was constructed, using indirect non-thermal plasma technology. The effects of different gas source flow rates on the quantity concentration, composition, and apparent activation energy of PM were investigated, using an engine exhaust particle sizer and a thermo-gravimetric analyzer. The results show that when the gas source flow rate was large, not only the maximum peak quantity concentrations of particles had a large drop, but also the peak quantity concentrations shifted to smaller particle sizes from 100 nm to 80 nm. When the gas source flow rate was 10 L min-1, the total quantity concentration greatly decreased where the removal rate of particles was 79.2%, and the variation of the different mode particle proportion was obvious. Non-thermal plasma (NTP) improved the oxidation ability of volatile matter as well as that of solid carbon. However, the NTP gas source rate had little effects on oxidation activity of volatile matter, while it strongly influenced the oxidation activity of solid carbon. Considering the quantity concentration and oxidation activity of particles, a gas source flow rate of 10 L min-1 was more appropriate for the purification of particles.

Spectroscopic Study of a Pulsed High-Energy Plasma Deflagration Accelerator

NASA Astrophysics Data System (ADS)

Loebner, Keith; Underwood, Thomas; Mouratidis, Theodore; Cappelli, Mark

2015-11-01

Observations of broadened Balmer lines emitted by a highly-ionized transient plasma jet are presented. A gated CCD camera coupled to a high-resolution spectrometer is used to obtain chord-averaged broadening data for a complete cross section of the plasma jet, and the data is Abel inverted to derive the radial plasma density distribution. This measurement is performed over narrow gate widths and at multiple axial positions to provide high spatial and temporal resolution. A streak camera coupled to a spectrometer is used to obtain continuous-time broadening data over the entire duration of the discharge event (10-50 microseconds). Analyses of discharge characteristics and comparisons with previous work are discussed. This work is supported by the U.S. Department of Energy Stewardship Science Academic Program, as well as the National Defense Science Engineering Graduate Fellowship.

Recent advances in plasma modeling for space applications

NASA Astrophysics Data System (ADS)

Srinivasan, Bhuvana; Scales, Wayne; Cagas, Petr; Glesner, Colin

2017-02-01

This paper presents a brief overview of the application of advanced plasma modeling techniques to several space science and engineering problems currently of significant interest. Recent advances in both kinetic and fluid modeling provide the ability to study a wide variety of problems that may be important to space plasmas including spacecraft-environment interactions, plasma-material interactions for propulsion systems such as Hall thrusters, ionospheric plasma instabilities, plasma separation from magnetic nozzles, active space experiments, and a host of additional problems. Some of the key findings are summarized here.

A DOE/Fusion Energy Sciences Research/Education Program at PVAMU Study of Rotamak Plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Tian-Sen; Saganti, Premkumar

capabilities. Apart from scientific staff members, several students (more than ten undergraduate students and two graduate students from several engineering and science disciplines) were supported and worked on the equipment and experiments during the award period. We also anticipate that these opportunities with current expansions may result in a graduate program in plasma science and propulsion engineering disciplines. *Corresponding Author – Dr. Saganti, Regents Professor and Professor of Physics – pbsaganti@pvamu.edu« less

Comparative study on nitridation and oxidation plasma interface treatment for AlGaN/GaN MIS-HEMTs with AlN gate dielectric

NASA Astrophysics Data System (ADS)

Zhu, Jie-Jie; Ma, Xiao-Hua; Hou, Bin; Chen, Li-Xiang; Zhu, Qing; Hao, Yue

2017-02-01

This paper demonstrated the comparative study on interface engineering of AlN/AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) by using plasma interface pre-treatment in various ambient gases. The 15 nm AlN gate dielectric grown by plasma-enhanced atomic layer deposition significantly suppressed the gate leakage current by about two orders of magnitude and increased the peak field-effect mobility by more than 50%. NH3/N2 nitridation plasma treatment (NPT) was used to remove the 3 nm poor-quality interfacial oxide layer and N2O/N2 oxidation plasma treatment (OPT) to improve the quality of interfacial layer, both resulting in improved dielectric/barrier interface quality, positive threshold voltage (V th) shift larger than 0.9 V, and negligible dispersion. In comparison, however, NPT led to further decrease in interface charges by 3.38 × 1012 cm-2 and an extra positive V th shift of 1.3 V. Analysis with fat field-effect transistors showed that NPT resulted in better sub-threshold characteristics and transconductance linearity for MIS-HEMTs compared with OPT. The comparative study suggested that direct removing the poor interfacial oxide layer by nitridation plasma was superior to improving the quality of interfacial layer by oxidation plasma for the interface engineering of GaN-based MIS-HEMTs.

Tripropellant Engine Study

NASA Technical Reports Server (NTRS)

Wheeler, D. B.

1977-01-01

The feasibility of modifying the space shuttle main engine (SSME) for dual mode operation was investigated. Various high power cycle engine configurations derived from the SSME were configurations that will allow sequential burning of LOX/hydrocarbon and LOX/hydrogen were studied in order to identify concepts that make maximum use of SSME hardware and best satisfy the dual mode booster engine system application. Engine cycles were formulated for LOX/RP-1, LOX/CH4, and LOX/C3H8 propellants. Flow rates and operating cycles were established and the adaptability of the major components of the SSME was evaluated.

Magnetohydrodynamic simulation study of plasma jets and plasma-surface contact in coaxial plasma accelerators

DOE PAGES

Subramaniam, Vivek; Raja, Laxminarayan L.

2017-06-13

Recent experiments by Loebner et al. [IEEE Trans. Plasma Sci. 44, 1534 (2016)] studied the effect of a hypervelocity jet emanating from a coaxial plasma accelerator incident on target surfaces in an effort to mimic the transient loading created during edge localized mode disruption events in fusion plasmas. In this study, we present a magnetohydrodynamic (MHD) numerical model to simulate plasma jet formation and plasma-surface contact in this coaxial plasma accelerator experiment. The MHD system of equations is spatially discretized using a cell-centered finite volume formulation. The temporal discretization is performed using a fully implicit backward Euler scheme and themore » resultant stiff system of nonlinear equations is solved using the Newton method. The numerical model is employed to obtain some key insights into the physical processes responsible for the generation of extreme stagnation conditions on the target surfaces. Simulations of the plume (without the target plate) are performed to isolate and study phenomena such as the magnetic pinch effect that is responsible for launching pressure pulses into the jet free stream. The simulations also yield insights into the incipient conditions responsible for producing the pinch, such as the formation of conductive channels. The jet-target impact studies indicate the existence of two distinct stages involved in the plasma-surface interaction. A fast transient stage characterized by a thin normal shock transitions into a pseudo-steady stage that exhibits an extended oblique shock structure. A quadratic scaling of the pinch and stagnation conditions with the total current discharged between the electrodes is in qualitative agreement with the results obtained in the experiments. Finally, this also illustrates the dominant contribution of the magnetic pressure term in determining the magnitude of the quantities of interest.« less

Magnetohydrodynamic simulation study of plasma jets and plasma-surface contact in coaxial plasma accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subramaniam, Vivek; Raja, Laxminarayan L.

Recent experiments by Loebner et al. [IEEE Trans. Plasma Sci. 44, 1534 (2016)] studied the effect of a hypervelocity jet emanating from a coaxial plasma accelerator incident on target surfaces in an effort to mimic the transient loading created during edge localized mode disruption events in fusion plasmas. In this study, we present a magnetohydrodynamic (MHD) numerical model to simulate plasma jet formation and plasma-surface contact in this coaxial plasma accelerator experiment. The MHD system of equations is spatially discretized using a cell-centered finite volume formulation. The temporal discretization is performed using a fully implicit backward Euler scheme and themore » resultant stiff system of nonlinear equations is solved using the Newton method. The numerical model is employed to obtain some key insights into the physical processes responsible for the generation of extreme stagnation conditions on the target surfaces. Simulations of the plume (without the target plate) are performed to isolate and study phenomena such as the magnetic pinch effect that is responsible for launching pressure pulses into the jet free stream. The simulations also yield insights into the incipient conditions responsible for producing the pinch, such as the formation of conductive channels. The jet-target impact studies indicate the existence of two distinct stages involved in the plasma-surface interaction. A fast transient stage characterized by a thin normal shock transitions into a pseudo-steady stage that exhibits an extended oblique shock structure. A quadratic scaling of the pinch and stagnation conditions with the total current discharged between the electrodes is in qualitative agreement with the results obtained in the experiments. Finally, this also illustrates the dominant contribution of the magnetic pressure term in determining the magnitude of the quantities of interest.« less

Plasma Physics at the National Science Foundation

NASA Astrophysics Data System (ADS)

Lukin, Vyacheslav

2017-10-01

The Town Meeting on Plasma Physics at the National Science Foundation will provide an opportunity for Q&A about the variety of NSF programs and solicitations relevant to a broad cross-section of the academic plasma science community, from graduating college seniors to senior leaders in the field, and from plasma astrophysics to basic physics to plasma engineering communities. We will discuss recent NSF-hosted events, research awards, and multi-agency partnerships aimed at enabling the progress of science in plasma science and engineering. Future outlook for plasma physics and broader plasma science support at NSF, with an emphasis on how you can help NSF to help the community, will be speculated upon within the uncertainty of the federal budgeting process.

Physics and engineering studies on the MITICA accelerator: comparison among possible design solutions

NASA Astrophysics Data System (ADS)

Agostinetti, P.; Antoni, V.; Cavenago, M.; Chitarin, G.; Pilan, N.; Marcuzzi, D.; Serianni, G.; Veltri, P.

2011-09-01

Consorzio RFX in Padova is currently using a comprehensive set of numerical and analytical codes, for the physics and engineering design of the SPIDER (Source for Production of Ion of Deuterium Extracted from RF plasma) and MITICA (Megavolt ITER Injector Concept Advancement) experiments, planned to be built at Consorzio RFX. This paper presents a set of studies on different possible geometries for the MITICA accelerator, with the objective to compare different design concepts and choose the most suitable one (or ones) to be further developed and possibly adopted in the experiment. Different design solutions have been discussed and compared, taking into account their advantages and drawbacks by both the physics and engineering points of view.

The influence of low-energy helium plasma on bubble formation in micro-engineered tungsten

NASA Astrophysics Data System (ADS)

Gao, Edward; Nadvornick, Warren; Doerner, Russ; Ghoniem, Nasr M.

2018-04-01

Four different types of micro-engineered tungsten surfaces were exposed to low energy helium plasma, with a planar surface as control. These samples include two surfaces covered with uniform W-coated rhenium micro-pillars; one with cylindrical pillars 1 μm in diameter and 25 μm in height, and one with dendritic conical pillars 4-10 μm in diameter and 20 μm in height. Additionally, two samples with reticulated open-cell foam geometry, one at 45 pores per inch (PPI), and the other at 80 PPI were fabricated with Chemical Vapor Deposition (CVD). The samples were exposed to helium plasma at 30-100 eV ion energy, 823-1123 K temperature, and 5 × 1025 - 2 × 1026 m-2 ion fluence. It is shown that the formation of nanometer-scale tendrils (fuzz) on micro-engineered W surfaces is greatly reduced as compared to planar surfaces. This is attributed to more significant ion backscattering and the increased effective surface area that intercept incident ions in micro-engineered W. A 20% decrease in the average ion incident angle on pillar type surfaces leads to ∼30% decrease in bubble size, down to 30 nm in diameter. W fuzz was found to be absent from pillar sides due to high ion backscattering rates from pillar sides. In foam samples, 28% higher PPI is observed to have 24.7%-36.7% taller fuzz, and 17.0%-25.0% larger subsurface bubbles. These are found to be an order of magnitude smaller than those found in planar surfaces of similar environment. The helium bubble density was found to increase with ion energy in pillars, roughly from 8.2% to 48.4%, and to increase with increasing PPI, from 36.4% to 116.2%, and with bubble concentrations up to 9.1 × 1021 m-3. Geometric shadowing effects in or near surface ligaments are observed in all foam samples, with near absence of helium bubbles or fuzz in deeper layers of the foam.

Automated Plasma Spray (APS) process feasibility study

NASA Technical Reports Server (NTRS)

Fetheroff, C. W.; Derkacs, T.; Matay, I. M.

1981-01-01

An automated plasma spray (APS) process was developed to apply two layer (NiCrAlY and ZrO2-12Y2O3) thermal barrier coatings to aircraft and stationary gas turbine engine blade airfoils. The APS process hardware consists of four subsystems: a mechanical positioning subsystem incorporating two interlaced six degree of freedom assemblies (one for coating deposition and one for coating thickness monitoring); a noncoherent optical metrology subsystem (for in process gaging of the coating thickness buildup at specified points on the specimen); a microprocessor based adaptive system controller (to achieve the desired overall thickness profile on the specimen); and commerical plasma spray equipment. Over fifty JT9D first stage aircraft turbine blade specimens, ten W501B utility turbine blade specimens and dozens of cylindrical specimens were coated with the APS process in preliminary checkout and evaluation studies. The best of the preliminary turbine blade specimens achieved an overall coating thickness uniformity of 53 micrometers (2.1 mils), much better than is achievable manually. Comparative evaluations of coating thickness uniformity for manually sprayed and APS coated specimens were performed. One of the preliminary turbine blade evaluation specimens was subjected to a torch test and metallographic evaluation. Some cylindrical specimens coated with the APS process survived up to 2000 cycles in subsequent burner rig testing.

Study of plasma parameters in a pulsed plasma accelerator using triple Langmuir probe

NASA Astrophysics Data System (ADS)

Borthakur, S.; Talukdar, N.; Neog, N. K.; Borthakur, T. K.

2018-01-01

A Triple Langmuir Probe (TLP) has been used to study plasma parameters of a transient plasma produced in a newly developed Pulsed Plasma Accelerator system. In this experiment, a TLP with a capacitor based current mode biasing circuit was used that instantaneously gives voltage traces in an oscilloscope which are directly proportional to the plasma electron temperature and density. The electron temperature (Te) and plasma density (ne) of the plasma are measured with the help of this probe and found to be 24.13 eV and 3.34 × 1021/m3 at the maximum energy (-15 kV) of the system, respectively. An attempt was also made to analyse the time-dependent fluctuations in plasma parameters detected by the highly sensitive triple probe. In addition to this, the variation of these parameters under different discharge voltages was studied. The information obtained from these parameters is the initial diagnostics of a new device which is to be dedicated to study the impact of high heat flux plasma stream upon material surfaces inside an ITER like tokamak.

Magnetohydrodynamic simulation study of plasma jets and plasma-surface contact in coaxial plasma accelerators

NASA Astrophysics Data System (ADS)

Subramaniam, Vivek; Raja, Laxminarayan L.

2017-06-01

Recent experiments by Loebner et al. [IEEE Trans. Plasma Sci. 44, 1534 (2016)] studied the effect of a hypervelocity jet emanating from a coaxial plasma accelerator incident on target surfaces in an effort to mimic the transient loading created during edge localized mode disruption events in fusion plasmas. In this paper, we present a magnetohydrodynamic (MHD) numerical model to simulate plasma jet formation and plasma-surface contact in this coaxial plasma accelerator experiment. The MHD system of equations is spatially discretized using a cell-centered finite volume formulation. The temporal discretization is performed using a fully implicit backward Euler scheme and the resultant stiff system of nonlinear equations is solved using the Newton method. The numerical model is employed to obtain some key insights into the physical processes responsible for the generation of extreme stagnation conditions on the target surfaces. Simulations of the plume (without the target plate) are performed to isolate and study phenomena such as the magnetic pinch effect that is responsible for launching pressure pulses into the jet free stream. The simulations also yield insights into the incipient conditions responsible for producing the pinch, such as the formation of conductive channels. The jet-target impact studies indicate the existence of two distinct stages involved in the plasma-surface interaction. A fast transient stage characterized by a thin normal shock transitions into a pseudo-steady stage that exhibits an extended oblique shock structure. A quadratic scaling of the pinch and stagnation conditions with the total current discharged between the electrodes is in qualitative agreement with the results obtained in the experiments. This also illustrates the dominant contribution of the magnetic pressure term in determining the magnitude of the quantities of interest.

Study of array plasma antenna parameters

NASA Astrophysics Data System (ADS)

Kumar, Rajneesh; Kumar, Prince

2018-04-01

This paper is aimed to investigate the array plasma antenna parameters to help the optimization of an array plasma antenna. Single plasma antenna is transformed into array plasma antenna by changing the operating parameters. The re-configurability arises in the form of striations, due to transverse bifurcation of plasma column by changing the operating parameters. Each striation can be treated as an antenna element and system performs like an array plasma antenna. In order to achieve the goal of this paper, three different configurations of array plasma antenna (namely Array 1, Array 2 and Array 3) are simulated. The observations are made on variation in antenna parameters like resonance frequency, radiation pattern, directivity and gain with variation in length and number of antenna elements for each array plasma antenna. Moreover experiments are also performed and results are compared with simulation. Further array plasma antenna parameters are also compared with monopole plasma antenna parameters. The study of present paper invoke the array plasma antenna can be applied for steering and controlling the strength of Wi-Fi signals as per requirement.

RF Antenna Design for a Helicon Plasma Source

NASA Astrophysics Data System (ADS)

Godden, Katarina; Stassel, Brendan; Warta, Daniel; Yep, Isaac; Hicks, Nathaniel; Munk, Jens

2017-10-01

A helicon plasma source is under development for the new Plasma Science and Engineering Laboratory at the University of Alaska Anchorage. The helicon source is of a type comprising Pyrex and stainless steel cylindrical sections, joined to an ultrahigh vacuum chamber. A radio frequency (RF) helical antenna surrounds the Pyrex chamber, as well as DC solenoidal magnetic field coils. This presentation focuses on the design of the RF helical antenna and RF matching network, such that helicon wave power is coupled to argon plasma with minimal reflected power to the RF amplifier. The amplifier output is selectable between 2-30 MHz, with forward c.w. power up to 1.5 kW. Details and computer simulation of the antenna geometry, materials, and power matching will be presented, as well as the matching network of RF transmission line, tuning capacitors, and cooling system. An initial computational study of power coupling to the plasma will also be described. Supported by U.S. NSF/DOE Partnership in Basic Plasma Science and Engineering Grant PHY-1619615, by the Alaska Space Grant Program, and by UAA Innovate 2017.

Theoretical Studies of Nonlinear Phenomena in Plasmas.

DTIC Science & Technology

1984-02-14

AD-Ai38 762 THEORETICAL STUDIES OF NONLINEAR PHENOMENA IN PLASMAS i/i, (U) MARYLAND UNIV COLLEUE FHRK LAB FOR PLASMA AND FUSION ENERGY STUDIES H H...Tnvestiga-tor: H. Chen 4 j DTIC $ELECTE ~ ~.UNIVERSITY OF MARYLAND * S 4ABORATORY FOR PLASMA AND FUSION ENERGY STUDIES " ’ ..COLLEGE PARK, MARYLAND 4k

Plasma chemistry study of PLAD processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin Shu; Brumfield, Kyle; Liu, Lequn Jennifer

2012-11-06

Plasma doping (PLAD) shows very different impurity profiles compared to the conventional beam-line-based ion implantations due to its non-mass separation property and plasma environment. There is no simulation for PLAD process so far due to a lack of a dopant profile model. Several factors determine impurity profiles of PLAD process. The most significant factors are: plasma chemistry and deposition/etching characteristics of multi-ion species plasmas. In this paper, we present plasma chemistry and deposition/etching characteristics of PLAD processes versus co-gas dilutions. Four dopant plasmas including B{sub 2}H{sub 6}, BF{sub 3}, AsH{sub 3}, and PH{sub 3}, and two non-dopant plasmas including CH{submore » 4} and GeH{sub 4} are studied and demonstrated.« less

The study of helicon plasma source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao Tingting; Shang Yong; Graduate University of Chinese Academy of Sciences, Beijing 100049

2010-02-15

Helicon plasma source is known as efficient generator of uniform and high density plasma. A helicon plasma source was developed for investigation of plasma neutralization and plasma lens in the Institute of Modern Physics in China. In this paper, the characteristics of helicon plasma have been studied by using Langmuir four-probe and a high argon plasma density up to 3.9x10{sup 13} cm{sup -3} have been achieved with the Nagoya type III antenna at the conditions of the magnetic intensity of 200 G, working gas pressure of 2.8x10{sup -3} Pa, and rf power of 1200 W with a frequency of 27.12more » MHz. In the experiment, the important phenomena have been found: for a given magnetic induction intensity, the plasma density became greater with the increase in rf power and tended to saturation, and the helicon mode appeared at the rf power between 200 and 400 W.« less

The study of helicon plasma source.

PubMed

Miao, Ting-Ting; Zhao, Hong-Wei; Liu, Zhan-Wen; Shang, Yong; Sun, Liang-Ting; Zhang, Xue-Zhen; Zhao, Huan-Yu

2010-02-01

Helicon plasma source is known as efficient generator of uniform and high density plasma. A helicon plasma source was developed for investigation of plasma neutralization and plasma lens in the Institute of Modern Physics in China. In this paper, the characteristics of helicon plasma have been studied by using Langmuir four-probe and a high argon plasma density up to 3.9x10(13) cm(-3) have been achieved with the Nagoya type III antenna at the conditions of the magnetic intensity of 200 G, working gas pressure of 2.8x10(-3) Pa, and rf power of 1200 W with a frequency of 27.12 MHz. In the experiment, the important phenomena have been found: for a given magnetic induction intensity, the plasma density became greater with the increase in rf power and tended to saturation, and the helicon mode appeared at the rf power between 200 and 400 W.

Low-thrust chemical rocket engine study

NASA Technical Reports Server (NTRS)

Mellish, J. A.

1981-01-01

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

Orbit transfer rocket engine technology program. Phase 2: Advanced engine study

NASA Technical Reports Server (NTRS)

Erickson, C.; Martinez, A.; Hines, B.

1987-01-01

In Phase 2 of the Advanced Engine Study, the Failure Modes and Effects Analysis (FMEA) maintenance-driven engine design, preliminary maintenance plan, and concept for space operable disconnects generated in Phase 1 were further developed. Based on the results of the vehicle contractors Orbit Transfer Vehicle (OTV) Concept Definition and System Analysis Phase A studies, minor revisions to the engine design were made. Additional refinements in the engine design were identified through further engine concept studies. These included an updated engine balance incorporating experimental heat transfer data from the Enhanced Heat Load Thrust Chamber Study and a Rao optimum nozzle contour. The preliminary maintenance plan of Phase 1 was further developed through additional studies. These included a compilation of critical component lives and life limiters and a review of the Space Shuttle Main Engine (SSME) operations and maintenance manual in order to begin outlining the overall maintenance procedures for the Orbit Transfer Vehicle Engine and identifying technology requirements for streamlining space-based operations. Phase 2 efforts also provided further definition to the advanced fluid coupling devices including the selection and preliminary design of a preferred concept and a preliminary test plan for its further development.

ECRH Studies on Tokamak Plasmas.

DTIC Science & Technology

1980-10-10

r.I*cru.Dtrtibution uUnliited 300 Unicorn Pork Drive Woburn, Massachusetts 04801 ECRH STUDIES ON TOKAMAK PLASMAS JAYCOR Project No. 6183 Final Report...up techniques now in use or being suggested, include growing the plasma from a small minor radius or applying a negative voltage spike immediately

Engine Lubricant

NASA Technical Reports Server (NTRS)

1993-01-01

PS 212, a plasma-sprayed coating developed by NASA, is used to coat valves in a new rotorcam engine. The coating eliminates the need for a liquid lubricant in the rotorcam, which has no crankshaft, flywheel, distributor or water pump. Developed by Murray United Development Corporation, it is a rotary engine only 10 inches long with four cylinders radiating outward from a central axle. Company officials say the engine will be lighter, more compact and cheaper to manufacture than current engines and will feature cleaner exhaust emissions. A licensing arrangement with a manufacturer is under negotiation. Primary applications are for automobiles, but the engine may also be used in light aircraft.

Studies on plasma profiles and its effect on dust charging in hydrogen plasma

NASA Astrophysics Data System (ADS)

Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhay, M.

2010-02-01

Plasma profiles and its influence on dust charging are studied in hydrogen plasma. The plasma is produced in a high vacuum device by a hot cathode discharge method and is confined by a cusped magnetic field cage. A cylindrical Espion advanced Langmuir probe having 0.15 mm diameter and 10.0 mm length is used to study the plasma parameters for various discharge conditions. Optimum operational discharge parameters in terms of charging of the dust grains are studied. The charge on the surface of the dust particle is calculated from the capacitance model and the current by the dust grains is measured by the combination of a Faraday cup and an electrometer. Unlike our previous experiments in which dust grains were produced in-situ, here a dust dropper is used to drop the dust particles into the plasma.

FOREWORD: 23rd National Symposium on Plasma Science & Technology (PLASMA-2008)

NASA Astrophysics Data System (ADS)

Das, A. K.

2010-01-01

The Twentieth Century has been a defining period for Plasma Science and Technology. The state of ionized matter, so named by Irving Langmuir in the early part of twentieth century, has now evolved in to a multidisciplinary area with scientists and engineers from various specializations working together to exploit the unique properties of the plasma medium. There have been great improvements in the basic understanding of plasmas as a many body system bound by complex collective Coulomb interactions of charges, atoms, molecules, free radicals and photons. Simultaneously, many advanced plasma based technologies are increasingly being implemented for industrial and societal use. The emergence of the multination collaborative project International Thermonuclear Experimental Reactor (ITER) project has provided the much needed boost to the researchers working on thermonuclear fusion plasmas. In addition, the other plasma applications like MHD converters, hydrogen generation, advanced materials (synthesis, processing and surface modification), environment (waste beneficiation, air and water pollution management), nanotechnology (synthesis, deposition and etching), light production, heating etc are actively being pursued in governmental and industrial sectors. For India, plasma science and technology has traditionally remained an important area of research. It was nearly a century earlier that the Saha ionization relation pioneered the way to interpret experimental data from a vast range of near equilibrium plasmas. Today, Indian research contributions and technology demonstration capabilities encompass thermonuclear fusion devices, nonlinear plasma phenomena, plasma accelerators, beam plasma interactions, dusty and nonneutral plasmas, industrial plasmas and plasma processing of materials, nano synthesis and structuring, astrophysical and space plasmas etc. India's participation in the ITER programme is now reflected in increased interest in the research and development

Gas-filled capillaries for plasma-based accelerators

NASA Astrophysics Data System (ADS)

Filippi, F.; Anania, M. P.; Brentegani, E.; Biagioni, A.; Cianchi, A.; Chiadroni, E.; Ferrario, M.; Pompili, R.; Romeo, S.; Zigler, A.

2017-07-01

Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented.

Protein Engineering: Case Studies of Commercialized Engineered Products

ERIC Educational Resources Information Center

Walsh, Gary

2007-01-01

Programs in biochemistry invariably encompass the principles of protein engineering. Students often display increased understanding and enthusiasm when theoretical concepts are underpinned by practical example. Herein are presented five case studies, each focusing upon a commercial protein product engineered to enhance its application-relevant…

Two-dimensional studies of relativistic electron beam plasma instabilities in an inhomogeneous plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shukla, Chandrasekhar; Das, Amita, E-mail: amita@ipr.res.in; Patel, Kartik

Relativistic electron beam propagation in plasma is fraught with several micro instabilities like two stream, filamentation, etc., in plasma. This results in severe limitation of the electron transport through a plasma medium. Recently, however, there has been an experimental demonstration of improved transport of Mega Ampere of electron currents (generated by the interaction of intense laser with solid target) in a carbon nanotube structured solid target [G. Chatterjee et al., Phys. Rev. Lett. 108, 235005 (2012)]. This then suggests that the inhomogeneous plasma (created by the ionization of carbon nanotube structured target) helps in containing the growth of the beammore » plasma instabilities. This manuscript addresses this issue with the help of a detailed analytical study and 2-D Particle-In-Cell simulations. The study conclusively demonstrates that the growth rate of the dominant instability in the 2-D geometry decreases when the plasma density is chosen to be inhomogeneous, provided the scale length 1/k{sub s} of the inhomogeneous plasma is less than the typical plasma skin depth (c/ω{sub 0}) scale. At such small scale lengths channelization of currents is also observed in simulation.« less

The study of data collection method for the plasma properties collection and evaluation system from web

NASA Astrophysics Data System (ADS)

Park, Jun-Hyoung; Song, Mi-Young; Plasma Fundamental Technology Research Team

2015-09-01

Plasma databases are necessarily required to compute the plasma parameters and high reliable databases are closely related with accuracy enhancement of simulations. Therefore, a major concern of plasma properties collection and evaluation system is to create a sustainable and useful research environment for plasma data. The system has a commitment to provide not only numerical data but also bibliographic data (including DOI information). Originally, our collection data methods were done by manual data search. In some cases, it took a long time to find data. We will be find data more automatically and quickly than legacy methods by crawling or search engine such as Lucene.

Plasma Torch for Plasma Ignition and Combustion of Coal

NASA Astrophysics Data System (ADS)

Ustimenko, Alexandr; Messerle, Vladimir

2015-09-01

Plasma-fuel systems (PFS) have been developed to improve coal combustion efficiency. PFS is a pulverized coal burner equipped with arc plasma torch producing high temperature air stream of 4000 - 6000 K. Plasma activation of coal at the PFS increases the coal reactivity and provides more effective ignition and ecologically friendly incineration of low-rank coal. The main and crucial element of PFS is plasma torch. Simplicity and reliability of the industrial arc plasma torches using cylindrical copper cathode and air as plasma forming gas predestined their application at heat and power engineering for plasma aided coal combustion. Life time of these plasma torches electrodes is critical and usually limited to 200 hours. Considered in this report direct current arc plasma torch has the cathode life significantly exceeded 1000 hours. To ensure the electrodes long life the process of hydrocarbon gas dissociation in the electric arc discharge is used. In accordance to this method atoms and ions of carbon from near-electrode plasma deposit on the active surface of the electrodes and form electrode carbon condensate which operates as ``actual'' electrode. Complex physicochemical investigation showed that deposit consists of nanocarbon material.

Experimental studies of collisional plasma shocks and plasma interpenetration via merging supersonic plasma jets

NASA Astrophysics Data System (ADS)

Hsu, S. C.; Moser, A. L.; Merritt, E. C.; Adams, C. S.

2015-11-01

Over the past 4 years on the Plasma Liner Experiment (PLX) at LANL, we have studied obliquely and head-on-merging supersonic plasma jets of an argon/impurity or hydrogen/impurity mixture. The jets are formed/launched by pulsed-power-driven railguns. In successive experimental campaigns, we characterized the (a) evolution of plasma parameters of a single plasma jet as it propagated up to ~ 1 m away from the railgun nozzle, (b) density profiles and 2D morphology of the stagnation layer and oblique shocks that formed between obliquely merging jets, and (c) collisionless interpenetration transitioning to collisional stagnation between head-on-merging jets. Key plasma diagnostics included a fast-framing CCD camera, an 8-chord visible interferometer, a survey spectrometer, and a photodiode array. This talk summarizes the primary results mentioned above, and highlights analyses of inferred post-shock temperatures based on observations of density gradients that we attribute to shock-layer thickness. We also briefly describe more recent PLX experiments on Rayleigh-Taylor-instability evolution with magnetic and viscous effects, and potential future collisionless shock experiments enabled by low-impurity, higher-velocity plasma jets formed by contoured-gap coaxial guns. Supported by DOE Fusion Energy Sciences and LANL LDRD.

Orbital transfer rocket engine technology: Advanced engine study

NASA Technical Reports Server (NTRS)

Hayden, Warren R.

1992-01-01

An advanced LOX/LH2 engine study for the use of NASA and vehicle prime contractors in developing concepts for manned missions to the Moon, Mars, and Phobos is documented. Parametric design data was obtained at five engine thrusts from 7.5K lbf to 50K lbf. Also, a separate task evaluated engine throttling over a 20:1 range and operation at a mixture ratio of 12 plus or minus 1 versus the 6 plus or minus 1 nominal. Cost data was also generated for DDT&E, first unit production, and factors in other life cycle costs. The major limitation of the study was lack of contact with vehicle prime contractors to resolve the issues in vehicle/engine interfaces. The baseline Aerojet dual propellant expander cycle was shown capable of meeting all performance requirements with an expected long operational life due to the high thermal margins. The basic engine design readily accommodated the 20:1 throttling requirement and operation up to a mixture ratio of 10 without change. By using platinum for baffled injector construction the increased thermal margin allowed operation up to mixture ratio 13. An initial engine modeling with an Aerojet transient simulation code (named MLETS) indicates stable engine operation with the baseline control system. A throttle ratio of 4 to 5 seconds from 10 percent to 100 percent thrust is also predicted. Performance predictions are 483.1 sec at 7.5K lbf, 487.3 sec at 20K lbf, and 485.2 sec at 50K lbf with a mixture ratio of 6 and an area ratio of 1200. Engine envelopes varied from 120 in. length/53 in. exit diameter at 7.5K lbf to 305 in. length/136 in. exit diameter at 50 K lbf. Packaging will be an important consideration. Continued work is recommended to include more vehicle prime contractor/engine contractor joint assessment of the interface issues.

Ceramic automotive Stirling engine study

NASA Technical Reports Server (NTRS)

Musikant, S.; Chiu, W.; Darooka, D.; Mullings, D. M.; Johnson, C. A.

1985-01-01

A conceptual design study for a Ceramic Automotive Stirling Engine (CASE) is performed. Year 1990 structural ceramic technology is assumed. Structural and performance analyses of the conceptual design are performed as well as a manufacturing and cost analysis. The general conclusions from this study are that such an engine would be 10-26% more efficient over its performance map than the current metal Automotive Stirling Reference Engine (ASRE). Cost of such a ceramic engine is likely to be somewhat higher than that of the ASRE but engine cost is very sensitive to the ultimate cost of the high purity, ceramic powder raw materials required to fabricate high performance parts. When the design study is projected to the year 2000 technology, substantinal net efficiency improvements, on the order of 25 to 46% over the ASRE, are computed.

Submillimeter Spectroscopic Study of Semiconductor Processing Plasmas

NASA Astrophysics Data System (ADS)

Helal, Yaser H.

Plasmas used for manufacturing processes of semiconductor devices are complex and challenging to characterize. The development and improvement of plasma processes and models rely on feedback from experimental measurements. Current diagnostic methods are not capable of measuring absolute densities of plasma species with high resolution without altering the plasma, or without input from other measurements. At pressures below 100 mTorr, spectroscopic measurements of rotational transitions in the submillimeter/terahertz (SMM) spectral region are narrow enough in relation to the sparsity of spectral lines that absolute specificity of measurement is possible. The frequency resolution of SMM sources is such that spectral absorption features can be fully resolved. Processing plasmas are a similar pressure and temperature to the environment used to study astrophysical species in the SMM spectral region. Many of the molecular neutrals, radicals, and ions present in processing plasmas have been studied in the laboratory and their absorption spectra have been cataloged or are in the literature for the purpose of astrophysical study. Recent developments in SMM devices have made its technology commercially available for applications outside of specialized laboratories. The methods developed over several decades in the SMM spectral region for these laboratory studies are directly applicable for diagnostic measurements in the semiconductor manufacturing industry. In this work, a continuous wave, intensity calibrated SMM absorption spectrometer was developed as a remote sensor of gas and plasma species. A major advantage of intensity calibrated rotational absorption spectroscopy is its ability to determine absolute concentrations and temperatures of plasma species from first principles without altering the plasma environment. An important part of this work was the design of the optical components which couple 500 - 750 GHz radiation through a commercial inductively coupled plasma

Engine monitoring display study

NASA Technical Reports Server (NTRS)

Hornsby, Mary E.

1992-01-01

The current study is part of a larger NASA effort to develop displays for an engine-monitoring system to enable the crew to monitor engine parameter trends more effectively. The objective was to evaluate the operational utility of adding three types of information to the basic Boeing Engine Indicating and Crew Alerting System (EICAS) display formats: alphanumeric alerting messages for engine parameters whose values exceed caution or warning limits; alphanumeric messages to monitor engine parameters that deviate from expected values; and a graphic depiction of the range of expected values for current conditions. Ten training and line pilots each flew 15 simulated flight scenarios with five variants of the basic EICAS format; these variants included different combinations of the added information. The pilots detected engine problems more quickly when engine alerting messages were included in the display; adding a graphic depiction of the range of expected values did not affect detection speed. The pilots rated both types of alphanumeric messages (alert and monitor parameter) as more useful and easier to interpret than the graphic depiction. Integrating engine parameter messages into the EICAS alerting system appears to be both useful and preferred.

Impact of an Engineering Case Study in a High School Pre-Engineering Course

ERIC Educational Resources Information Center

Rutz, Eugene; Shafer, Michelle

2011-01-01

Students at an all-girls high school who were enrolled in an introduction to engineering course were presented an engineering case study to determine if the case study affected their attitudes toward engineering and their abilities to solve engineering problems. A case study on power plants was implemented during a unit on electrical engineering.…

Study of supersonic plasma technology jets

NASA Astrophysics Data System (ADS)

Selezneva, Svetlana; Gravelle, Denis; Boulos, Maher; van de Sanden, Richard; Schram, Dc

2001-10-01

Recently some new techniques using remote thermal plasma for thin film deposition and plasma chemistry processes were developed. These techniques include PECVD of diamonds, diamond-like and polymer films; a-C:H and a-Si:H films. The latter are of especial interest because of their applications for solar cell production industry. In remote plasma deposition, thermal plasma is formed by means of one of traditional plasma sources. The chamber pressure is reduced with the help of continuous pumping. In that way the flow is accelerated up to the supersonic speed. The plasma expansion is controlled using a specific torch nozzle design. To optimize the deposition process detailed knowledge about the gas dynamic structure of the jet and chemical kinetics mechanisms is required. In the paper, we show how the flow pattern and the character of the deviations from local thermodynamic equilibrium differs in plasmas generated by different plasma sources, such as induction plasma torch, traditional direct current arc and cascaded arc. We study the effects of the chamber pressure, nozzle design and carrier gas on the resulting plasma properties. The analysis is performed by means of numerical modeling using commercially available FLUENT program with incorporated user-defined subroutines for two-temperature model. The results of continuum mechanics approach are compared with that of the kinetic Monte Carlo method and with the experimental data.

Design and Construction of Field Reversed Configuration Plasma Chamber for Plasma Material Interaction Studies

NASA Astrophysics Data System (ADS)

Smith, DuWayne L.

A Field Reversed Configuration (FRC) plasma source was designed and constructed to conduct high energy plasma-materials interaction studies. The purpose of these studies is the development of advanced materials for use in plasma based electric propulsion systems and nuclear fusion containment vessels. Outlined within this thesis is the basic concept of FRC plasmoid creation, an overview of the device design and integration of various diagnostics systems for plasma conditions and characterization, discussion on the variety of material defects resulting from the plasma exposure with methods and tools designed for characterization. Using a Michelson interferometer it was determined that the FRC plasma densities are on the order of ~1021 m-3. A novel dynamic pressure probe was created to measure ion velocities averaging 300 km/s. Compensating flux loop arrays were used to measure magnetic field strength and verify the existence of the FRC plasmoid and when used in combination with density measurements it was determined that the average ion temperatures are ~130 eV. X-ray Photoelectron Spectroscopy (XPS) was employed as a means of characterizing the size and shape of the plasma jet in the sample exposure positions. SEM results from preliminary studies reveal significant morphological changes on plasma facing material surfaces, and use of XRD to elucidate fuel gas-ion implantation strain rates correlated to plasma exposure energies.

Advanced engine study program

NASA Technical Reports Server (NTRS)

Masters, A. I.; Galler, D. E.; Denman, T. F.; Shied, R. A.; Black, J. R.; Fierstein, A. R.; Clark, G. L.; Branstrom, B. R.

1993-01-01

A design and analysis study was conducted to provide advanced engine descriptions and parametric data for space transfer vehicles. The study was based on an advanced oxygen/hydrogen engine in the 7,500 to 50,000 lbf thrust range. Emphasis was placed on defining requirements for high-performance engines capable of achieving reliable and versatile operation in a space environment. Four variations on the expander cycle were compared, and the advantages and disadvantages of each were assessed. Parametric weight, envelope, and performance data were generated over a range of 7,500 to 50,000 lb thrust and a wide range of chamber pressure and nozzle expansion ratio.

Review: engineering particles using the aerosol-through-plasma method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, Jonathan; Luhrs, Claudia C; Richard, Monique

2009-01-01

For decades, plasma processing of materials on the nanoscale has been an underlying enabling technology for many 'planar' technologies, particularly virtually every aspect of modern electronics from integrated-circuit fabrication with nanoscale elements to the newest generation of photovoltaics. However, it is only recent developments that suggest that plasma processing can be used to make 'particulate' structures of value in fields, including catalysis, drug delivery, imaging, higher energy density batteries, and other forms of energy storage. In this paper, the development of the science and technology of one class of plasma production of particulates, namely, aerosol-through-plasma (A-T-P), is reviewed. Various plasmamore » systems, particularly RF and microwave, have been used to create nanoparticles of metals and ceramics, as well as supported metal catalysts. Gradually, the complexity of the nanoparticles, and concomitantly their potential value, has increased. First, unique two-layer particles were generated. These were postprocessed to create unique three-layer nanoscale particles. Also, the technique has been successfully employed to make other high-value materials, including carbon nanotubes, unsupported graphene, and spherical boron nitride. Some interesting plasma science has also emerged from efforts to characterize and map aerosol-containing plasmas. For example, it is clear that even a very low concentration of particles dramatically changes plasma characteristics. Some have also argued that the local-thermodynamic-equilibrium approach is inappropriate to these systems. Instead, it has been suggested that charged- and neutral-species models must be independently developed and allowed to 'interact' only in generation terms.« less

Engineering Considerations for the Self-Energizing Magnetoplasmadynamic (MPD)-Type Fusion Plasma Thruster

DTIC Science & Technology

1992-02-01

Feasibility studies Of dense plasma focus (DPF) device as a fusion propulsion thruster have been performed. Both conventional and spin-polarized D...uncertainties remain in the validity of scaling laws on capacitor mass at high current beyond 1 MA. Fusion Propulsion, Dense Plasma Focus , Magnetoplasmadynamic Thruster, Advanced Fuel, D-3He Fusion, Spin-Polarized Fusion.

Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

NASA Astrophysics Data System (ADS)

Hansen, Stephanie

2017-10-01

The burning core of an inertial confinement fusion (ICF) plasma at stagnation is surrounded by a shell of warm, dense matter whose properties are difficult both to model (due to a complex interplay of thermal, degeneracy, and strong coupling effects) and to diagnose (due to low emissivity and high opacity). We demonstrate a promising technique to study the warm dense shells of ICF plasmas based on the fluorescence emission of dopants or impurities in the shell material. This emission, which is driven by x-rays produced in the hot core, exhibits signature changes in response to compression and heating. High-resolution measurements of absorption and fluorescence features can refine our understanding of the electronic structure of material under high compression, improve our models of density-driven phenomena such as ionization potential depression and plasma polarization shifts, and help diagnose shell density, temperature, mass distribution, and residual motion in ICF plasmas at stagnation. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525. This work was supported by the U.S. Department of Energy, Office of Science Early Career Research Program, Office of Fusion Energy Sciences under FWP-14-017426.

Spin-dependent excitation of plasma modes in non-neutral ion plasmas

NASA Astrophysics Data System (ADS)

Sawyer, Brian C.; Britton, Joe W.; Bollinger, John J.

2011-10-01

We report on a new technique for exciting and sensitively detecting plasma modes in small, cold non-neutral ion plasmas. The technique uses an optical dipole force generated from laser beams to excite plasma modes. By making the force spin- dependent (i.e. depend on the internal state of the atomic ion) very small mode excitations (<100 nm) can be detected through spin-motion entanglement. Even when the optical dipole force is homogeneous throughout the plasma, short wavelength modes on the order of the interparticle spacing can in principle be excited and detected through the spin dependence of the force. We use this technique to study the drumhead modes of single plane triangular arrays of a few hundred Be+ ions. Spin-dependent mode excitation is interesting in this system because it provides a means of engineering an Ising interaction on a 2-D triangular lattice. For the case of an anti-ferromagnetic interaction, this system exhibits spin frustration on a scale that is at present computationally intractable. Work supported by the DARPA OLE program and NIST.

Inverse mirror plasma experimental device (IMPED) - a magnetized linear plasma device for wave studies

NASA Astrophysics Data System (ADS)

Bose, Sayak; Chattopadhyay, P. K.; Ghosh, J.; Sengupta, S.; Saxena, Y. C.; Pal, R.

2015-04-01

In a quasineutral plasma, electrons undergo collective oscillations, known as plasma oscillations, when perturbed locally. The oscillations propagate due to finite temperature effects. However, the wave can lose the phase coherence between constituting oscillators in an inhomogeneous plasma (phase mixing) because of the dependence of plasma oscillation frequency on plasma density. The longitudinal electric field associated with the wave may be used to accelerate electrons to high energies by exciting large amplitude wave. However when the maximum amplitude of the wave is reached that plasma can sustain, the wave breaks. The phenomena of wave breaking and phase mixing have applications in plasma heating and particle acceleration. For detailed experimental investigation of these phenomena a new device, inverse mirror plasma experimental device (IMPED), has been designed and fabricated. The detailed considerations taken before designing the device, so that different aspects of these phenomena can be studied in a controlled manner, are described. Specifications of different components of the IMPED machine and their flexibility aspects in upgrading, if necessary, are discussed. Initial results meeting the prerequisite condition of the plasma for such study, such as a quiescent, collisionless and uniform plasma, are presented. The machine produces δnnoise/n <= 1%, Luniform ~ 120 cm at argon filling pressure of ~10-4 mbar and axial magnetic field of B = 1090 G.

Assessment of the toxic potential of engineered metal oxide nanomaterials using an acellular model: citrated rat blood plasma.

PubMed

Gormley, Patrick Thomas; Callaghan, Neal Ingraham; MacCormack, Tyson James; Dieni, Christopher Anthony

2016-10-01

Citrated Sprague-Dawley rat blood plasma was used as a biologically relevant exposure medium to assess the acellular toxic potential of two metal oxide engineered nanomaterials (ENMs), zinc oxide (nZnO), and cerium oxide (nCeO 2 ). Plasma was incubated at 37 °C for up to 48 h with ENM concentrations ranging between 0 and 200 mg/L. The degree of ENM-induced oxidation was assessed by assaying for reactive oxygen species (ROS) levels using dichlorofluorescein (DCF), pH, ferric reducing ability of plasma (FRAP), lipase activity, malondialdehyde (MDA), and protein carbonyls (PC). Whereas previous in vitro studies showed linear-positive correlations between ENM concentration and oxidative damage, our results suggested that low concentrations were generally pro-oxidant and higher concentrations appeared antioxidant or protective, as indicated by DCF fluorescence trends. nZnO and nCeO 2 also affected pH in a manner dependent on concentration and elemental composition; higher nZnO concentrations maintained a more alkaline pH, while nCeO 2 tended to decrease pH. No other biomarkers of oxidative damage (FRAP, MDA, PC, lipase activity) showed changes at any ENM concentration or time-point tested. Differential dissolution of the two ENMs was also observed, where as much as ∼31.3% of nZnO was instantaneously dissolved to Zn 2+  and only negligible nCeO 2 was degraded. The results suggest that the direct oxidative potential of nZnO and nCeO 2 in citrated rat blood plasma is low, and that a physiological or immune response is needed to generate appreciable damage biomarkers. The data also highlight the need for careful consideration when selecting a model for assessing ENM toxicity.

Feasibility Study for a Plasma Dynamo Facility to Investigate Fundamental Processes in Plasma Astrophysics. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forest, Cary B.

The scientific equipment purchased on this grant was used on the Plasma Dynamo Prototype Experiment as part of Professor Forest's feasibility study for determining if it would be worthwhile to propose building a larger plasma physics experiment to investigate various fundamental processes in plasma astrophysics. The initial research on the Plasma Dynamo Prototype Experiment was successful so Professor Forest and Professor Ellen Zweibel at UW-Madison submitted an NSF Major Research Instrumentation proposal titled "ARRA MRI: Development of a Plasma Dynamo Facility for Experimental Investigations of Fundamental Processes in Plasma Astrophysics." They received funding for this project and the Plasma Dynamomore » Facility also known as the "Madison Plasma Dynamo Experiment" was constructed. This experiment achieved its first plasma in the fall of 2012 and U.S. Dept. of Energy Grant No. DE-SC0008709 "Experimental Studies of Plasma Dynamos," now supports the research.« less

Status of Plasma Electron Hose Instability Studies in FACET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adli, Erik; /U. Oslo; England, Robert Joel

In the FACET plasma-wakefield acceleration experiment a dense 23 GeV electron beam will interact with lithium and cesium plasmas, leading to plasma ion-channel formation. The interaction between the electron beam and the plasma sheath-electrons may lead to a fast growing electron hose instability. By using optics dispersion knobs to induce a controlled z-x tilt along the beam entering the plasma, we investigate the transverse behavior of the beam in the plasma as function of the tilt. We seek to quantify limits on the instability in order to further explore potential limitations on future plasma wakefield accelerators due to the electronmore » hose instability. The FACET plasma-wakefield experiment at SLAC will study beam driven plasma wakefield acceleration. A dense 23 GeV electron beam will interact with lithium or cesium plasma, leading to plasma ion-channel formation. The interaction between the electron beam and the plasma sheath-electrons drives the electron hose instability, as first studied by Whittum. While Ref. [2] indicates the possibility of a large instability growth rate for typical beam and plasma parameters, other studies including have shown that several physical effects may mitigate the hosing growth rate substantially. So far there has been no quantitative benchmarking of experimentally observed hosing in previous experiments. At FACET we aim to perform such benchmarking by for example inducing a controlled z-x tilt along the beamentering the plasma, and observing the transverse behavior of the beam in the plasma as function. The long-term objective of these studies is to quantify potential limitations on future plasma wakefield accelerators due to the electron hose instability.« less

A study of single and binary ion plasma expansion into laboratory-generated plasma wakes

NASA Technical Reports Server (NTRS)

Wright, Kenneth Herbert, Jr.

1988-01-01

Plasma expansion into the wake of a large rectangular plate immersed in a collisionless, supersonic plasma was investigated in laboratory experiments. The experimental conditions address both single ion and binary ion plasma flows for the case of a body whose size is large in comparison with the Debye length, when the potential difference between the body and the plasma is relatively small. A new plasma source was developed to generate equi-velocity, binary ion plasma flows, which allows access to new parameter space that have previously been unavailable for laboratory studies. Specifically, the new parameters are the ionic mass ratio and the ionic component density ratio. In a series of experiments, a krypton-neon plasma is employed where the ambient density ratio of neon to krypton is varied more than an order of magnitude. The expansion in both the single ion and binary ion plasma cases is limited to early times, i.e., a few ion plasma periods, by the combination of plasma density, plasma drift speed, and vacuum chamber size, which prevented detailed comparison with self-similar theory.

A Segmented Ion-Propulsion Engine

NASA Technical Reports Server (NTRS)

Brophy, John R.

1992-01-01

New design approach for high-power (100-kW class or greater) ion engines conceptually divides single engine into combination of smaller discharge chambers integrated to operate as single large engine. Analogous to multicylinder automobile engine, benefits include reduction in required accelerator system span-to-gap ratio for large-area engines, reduction in required hollow-cathode emission current, mitigation of plasma-uniformity problem, increased tolerance to accelerator system faults, and reduction in vacuum-system pumping speed.

A new linear plasma device for various edge plasma studies at SWIP

NASA Astrophysics Data System (ADS)

Xu, Min; Zheng, Pengfei; Tynan, George; Che, Tong; Wang, Zhanhui; Guo, Dong; Wei, Ran

2017-10-01

To facilitate the plasma-material interactions (PMI) studies, Southwestern Institute of Physics (SWIP) has constructed a linear plasma device. It is comprised of a source chamber (Φ 0.4 m), a target chamber (Φ 0.9 m), 15 magnets with different sizes, and power supplies with the total power of a few hundred kilowatts, etc. A maximum magnetic field of 0.3 Tesla along the axial direction can be produced. The current of each of the 15 magnets can be independently controlled. More than 60 ports are available for diagnostics, with the sizes vary from Φ 50 mm to Φ 150 mm. Rectangular ports of 190 mm × 270 mm are also available. 12 ports looking at the sample holder are specially designed for ion beam injection, of which the axes are 25 to the chamber axis. The device is equipped with a LaB6 hot cathode plasma source, which is able to generate steady-state H/D/He plasmas with a diameter of Φ 100 mm, density of 1x1019 /m3 , and a particle flux of 1022 1023 n/m2 .s. The electron temperature is usually a few eV. Further, a Helicon RF plasma source is also planned for plasma transport studies. Int'l Sci & Tech Cooperation Program of China (No. 2015DFA61760).

Variable Specific Impulse Magnetoplasma Rocket Engine

NASA Technical Reports Server (NTRS)

Chang-Diaz, Franklin R. (Inventor)

2002-01-01

An engine is disclosed, including a controllable output plasma generator, a controllable heater for selectably raising a temperature of the plasma connected to an outlet of the plasma generator, and a nozzle connected to an outlet of the heater, through which heated plasma is discharged to provide thrust. In one embodiment, the source of plasma is a helicon generator. In one embodiment, the heater is an ion cyclotron resonator. In one embodiment, the nozzle is a radially diverging magnetic field disposed on a discharge side of the heater so that helically travelling particles in the beater exit the heater at high axial velocity. A particular embodiment includes control circuits for selectably directing a portion of radio frequency power from an RF generator to the helicon generator and to the cyclotron resonator so that the thrust output and the specific impulse of the engine can be selectively controlled. A method of propelling a vehicle is also disclosed. The method includes generating a plasma, heating said plasma, and discharging the heated plasma through a nozzle. In one embodiment, the nozzle is a diverging magnetic field. In this embodiment, the heating is performed by applying a radio frequency electro magnetic field to the plasma at the ion cyclotron frequency in an axially polarized DC magnetic field.

Stem cell responses to plasma surface modified electrospun polyurethane scaffolds.

PubMed

Zandén, Carl; Hellström Erkenstam, Nina; Padel, Thomas; Wittgenstein, Julia; Liu, Johan; Kuhn, H Georg

2014-07-01

The topographical effects from functional materials on stem cell behavior are currently of interest in tissue engineering and regenerative medicine. Here we investigate the influence of argon, oxygen, and hydrogen plasma surface modification of electrospun polyurethane fibers on human embryonic stem cell (hESC) and rat postnatal neural stem cell (NSC) responses. The plasma gases were found to induce three combinations of fiber surface functionalities and roughness textures. On randomly oriented fibers, plasma treatments lead to substantially increased hESC attachment and proliferation as compared to native fibers. Argon plasma was found to induce the most optimal combination of surface functionality and roughness for cell expansion. Contact guided migration of cells and alignment of cell processes were observed on aligned fibers. Neuronal differentiation around 5% was found for all samples and was not significantly affected by the induced variations of surface functional group distribution or individual fiber topography. In this study the influence of argon, oxygen, and hydrogen plasma surface modification of electrospun polyurethane fibers on human embryonic stem cell and rat postnatal neural stem cell (NSC) responses is studied with the goal of clarifying the potential effects of functional materials on stem cell behavior, a topic of substantial interest in tissue engineering and regenerative medicine. Copyright © 2014 Elsevier Inc. All rights reserved.

DOE-HEP Final Report for 2013-2016: Studies of plasma wakefields for high repetition-rate plasma collider, and Theoretical study of laser-plasma proton and ion acceleration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katsouleas, Thomas C.; Sahai, Aakash A.

2016-08-08

There were two goals for this funded project: 1. Studies of plasma wakefields for high repetition-rate plasma collider, and 2. Theoretical study of laser-plasma proton and ion acceleration. For goal 1, an analytical model was developed to determine the ion-motion resulting from the interaction of non-linear “blow-out” wakefields excited by beam-plasma and laser-plasma interactions. This is key to understanding the state of the plasma at timescales of 1 picosecond to a few 10s of picoseconds behind the driver-energy pulse. More information can be found in the document. For goal 2, we analytically and computationally analyzed the longitudinal instabilities of themore » laser-plasma interactions at the critical layer. Specifically, the process of “Doppler-shifted Ponderomotive bunching” is significant to eliminate the very high-energy spread and understand the importance of chirping the laser pulse frequency. We intend to publish the results of the mixing process in 2-D. We intend to publish Chirp-induced transparency. More information can be found in the document.« less

Development of Electrothermal Pulsed Plasma Thrusters for Osaka-Institute-of-Technology Electric-Rocket-Engine onboard Small Space Ship

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishii, Yushuke; Yamamoto, Tsuyoshi; Yamada, Minetsugu

2008-12-31

The Project of Osaka-Institute-of-Technology Electric-Rocket-Engine onboard Small Space Ship (PROITERES) was started at Osaka Institute of Technology. In PROITERES, a 10-kg small satellite with electrothermal pulsed plasma thrusters (PPTs), named JOSHO, will be launched in 2010. The main mission is powered flight of small satellite by electric thruster itself. Electrothermal PPTs were studied with both experiments and numerical simulations. An electrothermal PPT with a side-fed propellant feeding mechanism achieved a total impulse of 3.6 Ns with a repetitive 10000-shot operation. An unsteady numerical simulation showed the existence of considerable amount of ablation delaying to the discharge. However, it was alsomore » shown that this phenomenon should not be regarded as the 'late time ablation' for electrothermal PPTs.« less

Comprehensive Study of Plasma-Wall Sheath Transport Phenomena

DTIC Science & Technology

2012-09-10

environment, a Langmuir probe and a Retarding Potential Analyzer (RPA). The Langmuir probe could be considered the seminal plasma diagnostic, and a large...plasma-sheath interface. Electric field is normalized by Te/LD (LD is the Debye length) and velocity is normalized by the Bohm speed. Figure 14...studying the interaction of the near-wall plasma sheath with a magnetic field , and modeled the plasma sheath of the GT thick-sheath (~10mm) plasma

Vacuum application of thermal barrier plasma coatings

NASA Technical Reports Server (NTRS)

Holmes, R. R.; Mckechnie, T. N.

1988-01-01

Coatings are presently applied to Space Shuttle Main Engine (SSME) turbine blades for protection against the harsh environment realized in the engine during lift off-to-orbit. High performance nickel, chromium, aluminum, and yttrium (NiCrAlY) alloy coatings, which are applied by atmospheric plasma spraying, crack and spall off because of the severe thermal shock experienced during start-up and shut-down of the engine. Ceramic coatings of yttria stabilized zirconia (ZrO2-Y2O3) were applied initially as a thermal barrier over coating to the NiCrAlY but were removed because of even greater spalling. Utilizing a vacuum plasma spraying process, bond coatings of NiCrAlY were applied in a low pressure atmosphere of argon/helium, producing significantly improved coating-to-blade bonding. The improved coatings showed no spalling after 40 MSFC burner rig thermal shock cycles, cycling between 1700 and -423 F. The current atmospheric plasma NiCrAlY coatings spalled during 25 test cycles. Subsequently, a process was developed for applying a durable thermal barrier coating of ZrO2-Y2O3 to the turbine blades of first stage high-pressure fuel turbopumps utilizing the vacuum plasma process. The improved thermal barrier coating has successfully passed 40 burner rig thermal shock cycles without spalling. Hot firing in an SSME turbine engine is scheduled for the blades. Tooling was installed in preparation for vacuum plasma spray coating other SSME hardware, e.g., the titanium main fuel valve housing (MFVH) and the fuel turbopump nozzle/stator.

Topography preserved microwave plasma etching for top-down layer engineering in MoS2 and other van der Waals materials.

PubMed

Varghese, Abin; Sharma, Chithra H; Thalakulam, Madhu

2017-03-17

A generic and universal layer engineering strategy for van der Waals (vW) materials, scalable and compatible with the current semiconductor technology, is of paramount importance in realizing all-two-dimensional logic circuits and to move beyond the silicon scaling limit. In this letter, we demonstrate a scalable and highly controllable microwave plasma based layer engineering strategy for MoS 2 and other vW materials. Using this technique we etch MoS 2 flakes layer-by-layer starting from an arbitrary thickness and area down to the mono- or the few-layer limit. From Raman spectroscopy, atomic force microscopy, photoluminescence spectroscopy, scanning electron microscopy and transmission electron microscopy, we confirm that the structural and morphological properties of the material have not been compromised. The process preserves the pre-etch layer topography and yields a smooth and pristine-like surface. We explore the electrical properties utilising a field effect transistor geometry and find that the mobility values of our samples are comparable to those of the pristine ones. The layer removal does not involve any reactive gasses or chemical reactions and relies on breaking the weak inter-layer vW interaction making it a generic technique for a wide spectrum of layered materials and heterostructures. We demonstrate the wide applicability of the technique by extending it to other systems such as graphene, h-BN and WSe 2 . In addition, using microwave plasma in combination with standard lithography, we illustrate a lateral patterning scheme making this process a potential candidate for large scale device fabrication in addition to layer engineering.

Small Engine Component Technology (SECT) study

NASA Technical Reports Server (NTRS)

Larkin, T. R.

1986-01-01

The objective of this study is to identify high payoff technologies for year 2000 small gas turbine engines, and to provide a technology plan to guide research and technology efforts toward revolutionizing the small gas turbine technology base. The goal is to define the required technology to provide a 30 percent reduction in mission fuel burned, to reduce direct operating costs by at least 10 percent, and to provide increased reliability and durability of the gas turbine propulsion system. The baseline established to evaluate the year 2000 technology base was an 8-passenger commercial tilt-rotor aircraft powered by a current technology gas turbine engine. Three basic engine cycles were studied: the simple cycle engine, a waste heat recovery cycle, and a wave rotor engine cycle. For the simple cycle engine, two general arrangements were considered: the traditional concentric spool arrangement and a nonconcentric spool arrangement. Both a regenerative and a recuperative cycle were studied for the waste heat recovery cycle.

Town Meeting on Plasma Physics at the National Science Foundation

NASA Astrophysics Data System (ADS)

2015-11-01

We invite you to the Town Meeting on the role of the National Science Foundation (NSF) in supporting basic and applied research in Plasma Physics in the U.S. The overarching goal of NSF is to promote the progress of science and to enable training of the next generation of scientists and engineers at US colleges and universities. In this context, the role of the NSF Physics Division in leading the nearly 20 year old NSF/DOE Partnership in Basic Plasma Science and Engineering serves as an example of the long history of NSF support for basic plasma physics research. Yet, the NSF interest in maintaining a healthy university research base in plasma sciences extends across the Foundation. A total of five NSF Divisions are participating in the most recent Partnership solicitation, and a host of other multi-disciplinary and core programs provide opportunities for scientists to perform research on applications of plasma physics to Space & Solar Physics, Astrophysics, Accelerator Science, Material Science, Plasma Medicine, and many sub-disciplines within Engineering. This Town Meeting will provide a chance to discuss the full range of relevant NSF funding opportunities, and to begin a conversation on the present and future role of NSF in stewarding basic plasma science and engineering research at US colleges and universities. We would like to particularly encourage early career scientists and graduate students to participate in this Town Meeting, though everyone is invited to join what we hope to be a lively discussion.

Understanding the Accretion Engine in Pre-main Sequence Stars

NASA Astrophysics Data System (ADS)

Gómez de Castro, Ana I.

2009-05-01

Planetary systems are angular momentum reservoirs generated during star formation as a result of the joint action of gravity and angular momentum conservation. The accretion process drives to the generation of powerful engines able to drive the optical jets and the molecular outflows. A fraction of the engine energy is released into heating the circumstellar plasma to temperatures between 3000 K to 10 MK depending on the plasma location and density. There are very important unsolved problems concerning the nature of the engine, its evolution and its impact in the chemical evolution of the disk. Of special relevance is the understanding of the shear layer between the stellar photosphere and the disk; this layer controls a significant fraction of the magnetic field building up and the subsequent dissipative processes ought to be studied in the UV.

Small Engine Component Technology (SECT) study

NASA Technical Reports Server (NTRS)

Singh, B.

1986-01-01

Small advanced (450 to 850 pounds thrust, 2002 to 3781 N) gas turbine engines were studied for a subsonic strategic cruise missile application, using projected year 2000 technology. An aircraft, mission characteristics, and baseline (state-of-the-art) engine were defined to evaluate technology benefits. Engine performance and configuration analyses were performed for two and three spool turbofan and propfan engine concepts. Mission and Life Cycle Cost (LCC) analyses were performed in which the candidate engines were compared to the baseline engines over a prescribed mission. The advanced technology engines reduced system LCC up to 41 percent relative to the baseline engine. Critical aerodynamic, materials, and mechanical systems turbine engine technologies were identified and program plans were defined for each identified critical technology.

Case Study: Developing Graduate Engineers at Kentz Engineers & Constructors

ERIC Educational Resources Information Center

O'Donnell, Hugh; Karallis, Takis; Sandelands, Eric; Cassin, James; O'Neill, Donal

2008-01-01

Purpose: The aim of this paper is to outline the approach and process in place within Kentz Engineers & Constructors to develop graduate engineers on an international basis. Design/methodology/approach: The approach adopted is that of a case study which describes activities and processes within the organization and the rationale behind them,…

Articular cartilage tissue engineering with plasma-rich in growth factors and stem cells with nano scaffolds

NASA Astrophysics Data System (ADS)

Montaser, Laila M.; Abbassy, Hadeer A.; Fawzy, Sherin M.

2016-09-01

The ability to heal soft tissue injuries and regenerate cartilage is the Holy Grail of musculoskeletal medicine. Articular cartilage repair and regeneration is considered to be largely intractable due to the poor regenerative properties of this tissue. Due to their low self-repair ability, cartilage defects that result from joint injury, aging, or osteoarthritis, are the most often irreversible and are a major cause of joint pain and chronic disability. However, current methods do not perfectly restore hyaline cartilage and may lead to the apparition of fibro- or continue hypertrophic cartilage. The lack of efficient modalities of treatment has prompted research into tissue engineering combining stem cells, scaffold materials and environmental factors. The field of articular cartilage tissue engineering, which aims to repair, regenerate, and/or improve injured or diseased cartilage functionality, has evoked intense interest and holds great potential for improving cartilage therapy. Plasma-rich in growth factors (PRGF) and/or stem cells may be effective for tissue repair as well as cartilage regenerative processes. There is a great promise to advance current cartilage therapies toward achieving a consistently successful approach for addressing cartilage afflictions. Tissue engineering may be the best way to reach this objective via the use of stem cells, novel biologically inspired scaffolds and, emerging nanotechnology. In this paper, current and emergent approach in the field of cartilage tissue engineering is presented for specific application. In the next years, the development of new strategies using stem cells, in scaffolds, with supplementation of culture medium could improve the quality of new formed cartilage.

Tripropellant engine study

NASA Technical Reports Server (NTRS)

Wheeler, D. B.

1978-01-01

Engine performance data, combustion gas thermodynamic properties, and turbine gas parameters were determined for various high power cycle engine configurations derived from the space shuttle main engine that will allow sequential burning of LOX/hydrocarbon and LOX/hydrogen fuels. Both stage combustion and gas generator pump power cycles were considered. Engine concepts were formulated for LOX/RP-1, LOX/CH4, and LOX/C3H8 propellants. Flowrates and operating conditions were established for this initial set of engine systems, and the adaptability of the major components of shuttle main engine was investigated.

Mechanism of plasma-assisted ignition for H2 and C1-C5 hydrocarbons

NASA Astrophysics Data System (ADS)

Starikovskiy, Andrey; Aleksandrov, Nikolay

2016-09-01

Nonequilibrium plasma demonstrates ability to control ultra-lean, ultra-fast, low-temperature flames and appears to be an extremely promising technology for a wide range of applications, including aviation GTEs, piston engines, ramjets, scramjets and detonation initiation for pulsed detonation engines. To use nonequilibrium plasma for ignition and combustion in real energetic systems, one must understand the mechanisms of plasma-assisted ignition and combustion and be able to numerically simulate the discharge and combustion processes under various conditions. A new, validated mechanism for high-temperature hydrocarbon plasma assisted combustion was built and allows to qualitatively describe plasma-assisted combustion close and above the self-ignition threshold. The principal mechanisms of plasma-assisted ignition and combustion have been established and validated for a wide range of plasma and gas parameters. These results provide a basis for improving various energy-conversion combustion systems, from automobile to aircraft engines, using nonequilibrium plasma methods.

Plasma Effects

NASA Technical Reports Server (NTRS)

Armstrong, J. W.

1983-01-01

Radio communication with space probes requires sending signals through the Earth's ionosphere and usually the solar wind. During planetary flybys, the signal may also pass through the ionosphere of another planet. These ionized media can perturb the radio signal in a variety of ways. Examples of these perturbations are variations in the electrical length between the spacecraft and the ground station, Faraday rotation of linearly polarized signals, amplitude and phase scintillations, and spectral and angular broadening. These plasma effects can have undesirable influences on telemetry performance and thus need to be understood from a communications engineering viewpoint. The plasma effects are, however, useful from a scientific viewpoint, since the effects on the communications link can often be inverted to estimate the physical conditions in the plasma.

Study of Cryogenic Complex Plasma

DTIC Science & Technology

2008-10-27

nitrogen or liquid helium) and dust particles are introduced in the plasma. In YD-2, a cryogenic plasma is produced in the vapor of liquid helium above the...cryogenic liquid ( liquid nitrogen or liquid helium) and dust particles are introduced in the plasma. In YD-2, a cryogenic plasma is produced in the vapor...cryogenic liquid ( liquid nitrogen or liquid helium) in the Dewar bottle produces a stable plasma. We have been successful in producing a plasma (1

First experimental studies of ion flow in 3 ion species plasmas at the presheath-sheath transition

NASA Astrophysics Data System (ADS)

Severn, Greg

2016-09-01

The Bohm sheath criterion is studied with laser-induced fluorescence (LIF) in three ion species plasmas using two tunable diode lasers. KrI or HeI is added to a low pressure unmagnetized dc hot filament discharge in a mixture of argon and xenon gas confined by surface multi-dipole magnetic fields. The argon and xenon ion velocity distribution functions are measured at the sheath-presheath boundary near a negatively biased boundary plate. The potential structures of the plasma sheath and presheath are measured by an emissive probe. Results are compared with previous experiments with Ar-Xe plasmas, where the two ion species were observed to reach the sheath edge at nearly the same speed. This speed was the ion sound speed of the system, which is consistent with the generalized Bohm criterion. In such two ion species plasmas instability enhanced collisional friction (IEF) was demonstrated to exist which accounted for the observed results. When three ion species are present, it is demonstrated under most circumstances the ions do not fall out of the plasma at their individual Bohm velocities. It is also shown that under most circumstances the ions do not fall out of the plasma at the system sound speed. Results are consistent with the presence of instabilities. Author gratefully acknowledges collaborators Dr. Noah Hershkowtiz, Dr. Chi-Shung Yip, Dept. of Engineering Physics, Univ. Wisconsin-Madison, and Dr. Scott Baalrud, Dept. Physics, Univ. Iowa. Thanks to US DOE, grant DE-SC00014226.

Study of small turbofan engines applicable to single-engine light airplanes

NASA Technical Reports Server (NTRS)

Merrill, G. L.

1976-01-01

The design, efficiency and cost factors are investigated for application of turbofan propulsion engines to single engine, general aviation light airplanes. A companion study of a hypothetical engine family of a thrust range suitable to such aircraft and having a high degree of commonality of design features and parts is presented. Future turbofan powered light airplanes can have a lower fuel consumption, lower weight, reduced airframe maintenance requirements and improved engine overhaul periods as compared to current piston engined powered airplanes. Achievement of compliance with noise and chemical emission regulations is expected without impairing performance, operating cost or safety.

Orbit Transfer Rocket Engine Technology Program, Advanced Engine Study Task D.6

DTIC Science & Technology

1992-02-28

l!J~iliiJl 1. Report No. 2. Government Accession No. 3 . Recipient’s Catalog No. NASA 187215 4. Title and Subtitle 5. Report Date ORBIT TRANSFER ROCKET...Engine Study, three primary subtasks were accomplished: 1) Design and Parametric Data, 2) Engine Requirement Variation Studies, and 3 ) Vehicle Study...Mixture Ratio Parametrics 18 3 . Thrust Parametrics Off-Design Mixture Ratio Scans 22 4. Expansion Area Ratio Parametrics 24 5. OTV 20 klbf Engine Off

The upgraded Large Plasma Device, a machine for studying frontier basic plasma physics.

PubMed

Gekelman, W; Pribyl, P; Lucky, Z; Drandell, M; Leneman, D; Maggs, J; Vincena, S; Van Compernolle, B; Tripathi, S K P; Morales, G; Carter, T A; Wang, Y; DeHaas, T

2016-02-01

In 1991 a manuscript describing an instrument for studying magnetized plasmas was published in this journal. The Large Plasma Device (LAPD) was upgraded in 2001 and has become a national user facility for the study of basic plasma physics. The upgrade as well as diagnostics introduced since then has significantly changed the capabilities of the device. All references to the machine still quote the original RSI paper, which at this time is not appropriate. In this work, the properties of the updated LAPD are presented. The strategy of the machine construction, the available diagnostics, the parameters available for experiments, as well as illustrations of several experiments are presented here.

Definition study for variable cycle engine testbed engine and associated test program

NASA Technical Reports Server (NTRS)

Vdoviak, J. W.

1978-01-01

The product/study double bypass variable cycle engine (VCE) was updated to incorporate recent improvements. The effect of these improvements on mission range and noise levels was determined. This engine design was then compared with current existing high-technology core engines in order to define a subscale testbed configuration that simulated many of the critical technology features of the product/study VCE. Detailed preliminary program plans were then developed for the design, fabrication, and static test of the selected testbed engine configuration. These plans included estimated costs and schedules for the detail design, fabrication and test of the testbed engine and the definition of a test program, test plan, schedule, instrumentation, and test stand requirements.

Low-thrust chemical rocket engine study

NASA Technical Reports Server (NTRS)

Shoji, J. M.

1981-01-01

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

Plasma Chemistry of Vibrationally Nonequilibrium Molecules

DTIC Science & Technology

1993-11-01

WL-TR-93-2116 PLASMA CHEMISTRY OF VIBRATIONALLY NONEQUILIBRIUM MOLECULES AD-A279 630--, J. WILLIAM RICH DEPARTMENT OF MECHANICAL ENGINEERING D THE...1AT9E L. REPORT TYPE AND DATES COVERED ONLY Man"_November 1993 Final 09 July 1990_- 08 July 1993 4 MITL AND SUBTITLE S. FUNDNG NUMERS & Plasma Chemistry of...k14. SUBIECT TERMS 15. NUMBER OF PAGES Molecular Energy Transfer; Plasma Chemistry ; Ionization; 4% Vibrational Relaxation; Nitric Oxide; Carbon

Spectroscopy Study of Ar + CO2 Plasmas in ASTRAL.

NASA Astrophysics Data System (ADS)

Munoz, Jorge; Boivin, Robert; Kamar, Ola; Loch, Stuart; Ballance, Connor

2006-10-01

A spectroscopy study of the ASTRAL (Auburn Steady sTate Research fAciLity) helicon plasma source running Ar + CO2 gas mix is presented. ASTRAL produces Ar plasmas: ne = 10^10 to 10^13 cm-3, Te = 2 to 10 eV and Ti = 0.03 to 0.5 eV. A series of 7 large coils produce an axial magnetic field up to 1.3 kGauss. A fractional helix antenna is used to introduce rf power up to 2 kWatt. A spectrometer which features a 0.33 m Criss-Cross monochromator and a CCD camera is used for this study. Very different plasmas are produced following the relative importance of CO2 in the gas mixture. At low CO2 concentration, the plasmas are similar to those obtained with pure Ar with weak CO2, CO2^+, CO and CO^+ bands. The usual blue plasma core associated with intense Ar II transitions is observed with however a significant white glow coming from the outer plasma regions. At higher CO2 concentration, the plasma becomes essentially molecular and can be described as an intense white plasma column. Molecular dissociative processes associated with the production of strong C and O atomic lines are observed under specific plasma conditions. The atomic spectral lines are compared with ADAS modeling results. This study indicates the possible advantages of using a helicon source to control the CO2 plasma chemistry for industrial applications.

Helical plasma thruster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beklemishev, A. D., E-mail: bekl@bk.ru

2015-10-15

A new scheme of plasma thruster is proposed. It is based on axial acceleration of rotating magnetized plasmas in magnetic field with helical corrugation. The idea is that the propellant ionization zone can be placed into the local magnetic well, so that initially the ions are trapped. The E × B rotation is provided by an applied radial electric field that makes the setup similar to a magnetron discharge. Then, from the rotating plasma viewpoint, the magnetic wells of the helically corrugated field look like axially moving mirror traps. Specific shaping of the corrugation can allow continuous acceleration of trapped plasma ionsmore » along the magnetic field by diamagnetic forces. The accelerated propellant is expelled through the expanding field of magnetic nozzle. By features of the acceleration principle, the helical plasma thruster may operate at high energy densities but requires a rather high axial magnetic field, which places it in the same class as the VASIMR{sup ®} rocket engine.« less

Plasma Sources for Medical Applications - A Comparison of Spot Like Plasmas and Large Area Plasmas

NASA Astrophysics Data System (ADS)

Weltmann, Klaus-Dieter

2015-09-01

Plasma applications in life science are currently emerging worldwide. Whereas today's commercially available plasma surgical technologies such as argon plasma coagulation (APC) or ablation are mainly based on lethal plasma effects on living systems, the newly emerging therapeutic applications will be based on selective, at least partially non-lethal, possibly stimulating plasma effects on living cells and tissue. Promising results could be obtained by different research groups worldwide revealing a huge potential for the application of low temperature atmospheric pressure plasma in fields such as tissue engineering, healing of chronic wounds, treatment of skin diseases, tumor treatment based on specific induction of apoptotic processes, inhibition of biofilm formation and direct action on biofilms or treatment of dental diseases. The development of suitable and reliable plasma sources for the different therapies requires an in-depth knowledge of their physics, chemistry and parameters. Therefore much basic research still needs to be conducted to minimize risk and to provide a scientific fundament for new plasma-based medical therapies. It is essential to perform a comprehensive assessment of physical and biological experiments to clarify minimum standards for plasma sources for applications in life science and for comparison of different sources. One result is the DIN-SPEC 91315, which is now open for further improvements. This contribution intends to give an overview on the status of commercial cold plasma sources as well as cold plasma sources still under development for medical use. It will discuss needs, prospects and approaches for the characterization of plasmas from different points of view. Regarding the manageability in everyday medical life, atmospheric pressure plasma jets (APPJ) and dielectric barrier discharges (DBD) are of special interest. A comprehensive risk-benefit assessment including the state of the art of commercial sources for medical use

Numerical studies of wall–plasma interactions and ionization phenomena in an ablative pulsed plasma thruster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Lei; School of Astronautics, Beihang University, Beijing 100191; Zeng, Guangshang

2016-07-15

Wall–plasma interactions excited by ablation controlled arcs are very critical physical processes in pulsed plasma thrusters (PPTs). Their effects on the ionization processes of ablated vapor into discharge plasma directly determine PPT performances. To reveal the physics governing the ionization phenomena in PPT discharge, a modified model taking into account the pyrolysis effect of heated polytetrafluoroethylene propellant on the wall–plasma interactions was developed. The feasibility of the modified model was analyzed by creating a one-dimensional simulation of a rectangular ablative PPT. The wall–plasma interaction results based on this modified model were found to be more realistic than for the unmodifiedmore » model; this reflects the dynamic changes of the inflow parameters during discharge in our model. Furthermore, the temporal and spatial variations of the different plasma species in the discharge chamber were numerically studied. The numerical studies showed that polytetrafluoroethylene plasma was mainly composed of monovalent ions; carbon and fluorine ions were concentrated in the upstream and downstream discharge chamber, respectively. The results based on this modified model were in good agreement with the experimental formation times of the various plasma species. A large number of short-lived and highly ionized carbon and fluorine species (divalent and trivalent ions) were created during initial discharge. These highly ionized species reached their peak density earlier than the singly ionized species.« less

General Aviation Turbine Engine (GATE) study

NASA Technical Reports Server (NTRS)

Baerst, C. F.; Furst, D. G.

1979-01-01

The feasibility of turbine engines for the smaller general aviation aircraft was investigated and a technology program for developing the necessary technology was identified. Major results included the definition of the 1988 general aviation market, the identification of turboprop and turboshaft engines that meet the requirements of the aircraft studies, a benefit analysis showing the superiority of gas turbine engines for portions of the market studied, and detailed plans for the development of the necessary technology.

Computational study of nonlinear plasma waves. [plasma simulation model applied to electrostatic waves in collisionless plasma

NASA Technical Reports Server (NTRS)

Matsuda, Y.

1974-01-01

A low-noise plasma simulation model is developed and applied to a series of linear and nonlinear problems associated with electrostatic wave propagation in a one-dimensional, collisionless, Maxwellian plasma, in the absence of magnetic field. It is demonstrated that use of the hybrid simulation model allows economical studies to be carried out in both the linear and nonlinear regimes with better quantitative results, for comparable computing time, than can be obtained by conventional particle simulation models, or direct solution of the Vlasov equation. The characteristics of the hybrid simulation model itself are first investigated, and it is shown to be capable of verifying the theoretical linear dispersion relation at wave energy levels as low as .000001 of the plasma thermal energy. Having established the validity of the hybrid simulation model, it is then used to study the nonlinear dynamics of monochromatic wave, sideband instability due to trapped particles, and satellite growth.

The Basic Plasma Science Facility: a platform for studying plasma processes relevant to space and astrophysical settings

NASA Astrophysics Data System (ADS)

Carter, T. A.

2017-10-01

The Basic Plasma Science Facility at UCLA is a national user facility for studies of fundamental processes in magnetized plasmas. The centerpiece is the Large Plasma Device, a 20 m, magnetized linear plasma device. Two hot cathode plasma sources are available. A Barium Oxide coated cathode produces plasmas with n 1012 cm-3, Te 5 eV, Ti < 1 eV with magnetic field from 400G-2kG. This low- β plasma has been used to study fundamental processes, including: dispersion and damping of kinetic and inertial Alfvén waves, flux ropes and magnetic reconnection, three-wave interactions and parametric instabilities of Alfvén waves, turbulence and transport, and interactions of energetic ions and electrons with plasma waves. A new Lanthanum Hexaboride (LaB6) cathode is now available which produces significantly higher densities and temperatures: n < 5 ×1013 cm-3, Te 12 eV, Ti 6 eV. This higher pressure plasma source enabled the observation of laser-driven collisionless magnetized shocks and, with lowered magnetic field, provides magnetized plasmas with β approaching or possibly exceeding unity. This opens up opportunities for investigating processes relevant to the solar wind and astrophysical plasmas. BaPSF is jointly supported by US DOE and NSF.

Studies on Charge Variation and Waves in Dusty Plasmas

NASA Astrophysics Data System (ADS)

Kausik, Siddhartha Sankar

Plasma and dust grains are both ubiquitous ingredients of the universe. The interplay between them has opened up a new and fascinating research domain, that of dusty plasmas, which contain macroscopic particles of solid matter besides the usual plasma constituents. The research in dusty plasmas received a major boost in the early eighties with Voyager spacecraft observation on the formation of Saturn rings. Dusty plasmas are defined as partially or fully-ionized gases that contain micron-sized particles of electrically charged solid material, either dielectric or conducting. The physics of dusty plasmas has recently been studied intensively because of its importance for a number of applications in space and laboratory plasmas. This thesis presents the experimental studies on charge variation and waves in dusty plasmas. The experimental observations are carried out in two different experimental devices. Three different sets of experiments are carried out in two different experimental devices. Three different sets of experiments are carried out to study the dust charge variation in a filament discharge argon plasma. The dust grains used in these experiments are grains of silver. In another get of experiment, dust acoustic waves are studied in a de glow discharge argon plasma. Alumina dust grains are sprinkled in this experiment. The diagnostic tools used in these experiments are Langmuir probe and Faraday cup. The instruments used in these experiments are electrometer, He-Ne laser and charge coupled device (CCD) camera. Langmuir probe is used to measure plasma parameters, while Faraday cup and electrometer are used to measure very low current (~pA) carried by a collimated dust beam. He-Ne laser illuminates the dust grains and CCD camera is used to capture the images of dust acoustic waves. Silver dust grains are produced in the dust chamber by gas-evaporation technique. Due to differential pressure maintained between the dust and plasma chambers, the dust grains move

System Study for Axial Vane Engine Technology

NASA Technical Reports Server (NTRS)

Badley, Patrick R.; Smith, Michael R.; Gould, Cedric O.

2008-01-01

The purpose of this engine feasibility study was to determine the benefits that can be achieved by incorporating positive displacement axial vane compression and expansion stages into high bypass turbofan engines. These positive-displacement stages would replace some or all of the conventional compressor and turbine stages in the turbine engine, but not the fan. The study considered combustion occurring internal to an axial vane component (i.e., Diesel engine replacing the standard turbine engine combustor, burner, and turbine); and external continuous flow combustion with an axial vane compressor and an axial vane turbine replacing conventional compressor and turbine systems.

Tripropellant engine study

NASA Technical Reports Server (NTRS)

Wheeler, D. B.

1977-01-01

Work conducted was devoted to three main tasks. Thermochemical equilibrium performance data were assembled to establish the expected performance calculations of the mode 1 engine propellant combinations and thermodynamic and transport data for the products of combustion. Turbine drive gas characteristics were also established. Thrust chamber and nozzle cooling studies were devoted to the evaluation of H2, C3H8, CH4, and RP-1 as coolants in the existing SSME cooling circuit geometry. It was found that all these candidate coolants are feasible without limiting the desired operating conditions with the exception of RP-1, which would limit the maximum P(c) to 2000 psia. RP-1 could be used, however, to cool the nozzle only without imposing the chamber pressure limit. A total of 15 candidate engine system cycles were selected and a preliminary engine system balance was conducted for 12 of these systems to establish component operating flowrates, pressures and temperatures. It was found that the staged combustion cycles employing fuel rich LOX/hydrocarbon turbine drive gases are power limited.

Coating Bores of Light Metal Engine Blocks with a Nanocomposite Material using the Plasma Transferred Wire Arc Thermal Spray Process

NASA Astrophysics Data System (ADS)

Bobzin, K.; Ernst, F.; Zwick, J.; Schlaefer, T.; Cook, D.; Nassenstein, K.; Schwenk, A.; Schreiber, F.; Wenz, T.; Flores, G.; Hahn, M.

2008-09-01

Engine blocks of modern passenger car engines are generally made of light metal alloys, mostly hypoeutectic AlSi-alloys. Due to their low hardness, these alloys do not meet the tribological requirements of the system cylinder running surface—piston rings—lubricating oil. In order to provide a suitable cylinder running surface, nowadays cylinder liners made of gray cast iron are pressed in or cast into the engine block. A newer approach is to apply thermal spray coatings onto the cylinder bore walls. Due to the geometric conditions, the coatings are applied with specifically designed internal diameter thermal spray systems. With these processes a broad variety of feedstock can be applied, whereas mostly low-alloyed carbon steel feedstock is being used for this application. In the context of this work, an iron-based wire feedstock has been developed, which leads to a nanocrystalline coating. The application of this material was carried out with the Plasma Transferred Wire Arc system. AlMgSi0.5 liners were used as substrates. The coating microstructure and the properties of the coatings were analyzed.

Design and Construction of a Dense Plasma Focus Device

DTIC Science & Technology

1976-10-01

This paper deals with the design of a dense plasma focus device as an engineering project. Essentially this approach can be summarized as follows...First, an introduction dealing with a general discussion of plasma devices focusing on the role of a dense plasma focus device as a useful tool in...future research; second, an explanation of the operation of the dense plasma focus ; third, a general design discussion of the dense plasma focus device

Study of T53 engine vibration

NASA Technical Reports Server (NTRS)

Walter, T. J.

1978-01-01

Vibration characteristics for overhauled T53 engines, including rejection rate, principal sources of vibration, and normal procedures taken by the overhaul center to reduce engine vibration are summarized. Analytical and experimental data were compared to determine the engine's dynamic response to unbalance forces with results showing that the engine operates through bending critical speeds. Present rigid rotor balancing techniques are incapable of compensating for the flexible rotor unbalance. A comparison of typical test cell and aircraft vibration levels disclosed significant differences in the engine's dynamic response. A probable spline shift phenomenon was uncovered and investigated. Action items to control costs and reduce vibration levels were identified from analytical and experimental studies.

Space plasma branch at NRL

NASA Astrophysics Data System (ADS)

The Naval Research Laboratory (Washington, D.C.) formed the Space Plasma Branch within its Plasma Physics Division on July 1. Vithal Patel, former Program Director of Magnetospheric Physics, National Science Foundation, also joined NRL on the same date as Associate Superintendent of the Plasma Physics Division. Barret Ripin is head of the newly organized branch. The Space Plasma branch will do basic and applied space plasma research using a multidisciplinary approach. It consolidates traditional rocket and satellite space experiments, space plasma theory and computation, with laboratory space-related experiments. About 40 research scientists, postdoctoral fellows, engineers, and technicians are divided among its five sections. The Theory and Computation sections are led by Joseph Huba and Joel Fedder, the Space Experiments section is led by Paul Rodriguez, and the Pharos Laser Facility and Laser Experiments sections are headed by Charles Manka and Jacob Grun.

Study of Plasma Flows Generated in Plasma Focus Discharge in Different Regimes of Working Gas Filling

NASA Astrophysics Data System (ADS)

Voitenko, D. A.; Ananyev, S. S.; Astapenko, G. I.; Basilaia, A. D.; Markolia, A. I.; Mitrofanov, K. N.; Myalton, V. V.; Timoshenko, A. P.; Kharrasov, A. M.; Krauz, V. I.

2017-12-01

Results are presented from experimental studies of the plasma flows generated in the KPF-4 Phoenix Mather-type plasma focus device (Sukhum Physical Technical Institute). In order to study how the formation and dynamics of the plasma flow depend on the initial distribution of the working gas, a system of pulsed gas puffing into the discharge volume was developed. The system allows one to create profiled gas distributions, including those with a reduced gas density in the region of plasma flow propagation. Results of measurements of the magnetic field, flow profile, and flow deceleration dynamics at different initial distributions of the gas pressure are presented.

Plasma-assisted catalytic storage reduction system

DOEpatents

Penetrante, Bernardino M.; Vogtlin, George E.; Merritt, Bernard T.; Brusasco, Raymond M.

2000-01-01

A two-stage method for NO.sub.x reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO.sub.x gases in an oxygen-rich exhaust and is intended to convert NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. The second stage employs a lean NO.sub.x trap to convert such NO.sub.2 to environmentally benign gases that include N.sub.2, CO.sub.2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage with a plasma, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, such as propene. A flow of such hydrocarbons (C.sub.x H.sub.y) is input from usually a second pipe into at least a portion of the first chamber. The NO.sub.2 from the plasma treatment proceeds to a storage reduction catalyst (lean NO.sub.x trap) that converts NO.sub.2 to N.sub.2, CO.sub.2, and H.sub.2 O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the lean-NO.sub.x trap catalyst. The method allows for enhanced NO.sub.x reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.

Plasma-assisted catalytic storage reduction system

DOEpatents

Penetrante, Bernardino M.; Vogtlin, George E.; Merritt, Bernard T.; Brusasco, Raymond M.

2002-01-01

A two-stage method for NO.sub.x reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO.sub.x gases in an oxygen-rich exhaust and is intended to convert NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. The second stage employs a lean NO.sub.x trap to convert such NO.sub.2 to environmentally benign gases that include N.sub.2, CO.sub.2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage with a plasma, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, such as propene. A flow of such hydrocarbons (C.sub.x H.sub.y) is input from usually a second pipe into at least a portion of the first chamber. The NO.sub.2 from the plasma treatment proceeds to a storage reduction catalyst (lean NO.sub.x trap) that converts NO.sub.2 to N.sub.2, CO.sub.2, and H.sub.2 O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the lean-NO.sub.x trap catalyst. The method allows for enhanced NO.sub.x reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.

Tripropellant engine study

NASA Technical Reports Server (NTRS)

Wheeler, D. B.; Kirby, F. M.

1978-01-01

The potential for converting the space shuttle main engine (SSME) to a dual-fuel, dual-mode engine using LOX/hydrocarbon propellants in mode 1 and LOX/H2 in mode 2 was examined. Various engine system concepts were formulated that included staged combustion and gas generator turbine power cycles, and LOX/RP-1, LOX/CH4, and LOX/C3H8 mode 1 propellants. Both oxidizer and fuel regenerative cooling were considered. All of the SSME major components were examined to determine their adaptability to the candidate dual-fuel engines.

[Experimental study on spectra of compressed air microwave plasma].

PubMed

Liu, Yong-Xi; Zhang, Gui-Xin; Wang, Qiang; Hou, Ling-Yun

2013-03-01

Using a microwave plasma generator, compressed air microwave plasma was excited under 1 - 5 atm pressures. Under different pressures and different incident microwave power, the emission spectra of compressed air microwave plasma were studied with a spectra measuring system. The results show that continuum is significant at atmospheric pressure and the characteristic will be weakened as the pressure increases. The band spectra intensity will be reduced with the falling of the incident microwave power and the band spectra were still significant. The experimental results are valuable to studying the characteristics of compressed air microwave plasma and the generating conditions of NO active groups.

Clustered engine study

NASA Technical Reports Server (NTRS)

Shepard, Kyle; Sager, Paul; Kusunoki, Sid; Porter, John; Campion, AL; Mouritzan, Gunnar; Glunt, George; Vegter, George; Koontz, Rob

1993-01-01

Several topics are presented in viewgraph form which together encompass the preliminary assessment of nuclear thermal rocket engine clustering. The study objectives, schedule, flow, and groundrules are covered. This is followed by the NASA groundrules mission and our interpretation of the associated operational scenario. The NASA reference vehicle is illustrated, then the four propulsion system options are examined. Each propulsion system's preliminary design, fluid systems, operating characteristics, thrust structure, dimensions, and mass properties are detailed as well as the associated key propulsion system/vehicle interfaces. A brief series of systems analysis is also covered including: thrust vector control requirements, engine out possibilities, propulsion system failure modes, surviving system requirements, and technology requirements. An assessment of vehicle/propulsion system impacts due to the lessons learned are presented.

Laboratory study of collisionless coupling between explosive debris plasma and magnetized ambient plasma

NASA Astrophysics Data System (ADS)

Bondarenko, A. S.; Schaeffer, D. B.; Everson, E. T.; Clark, S. E.; Lee, B. R.; Constantin, C. G.; Vincena, S.; Van Compernolle, B.; Tripathi, S. K. P.; Winske, D.; Niemann, C.

2017-08-01

The explosive expansion of a localized plasma cloud into a relatively tenuous, magnetized, ambient plasma characterizes a variety of astrophysical and space phenomena. In these rarified environments, collisionless electromagnetic processes rather than Coulomb collisions typically mediate the transfer of momentum and energy from the expanding "debris" plasma to the surrounding ambient plasma. In an effort to better understand the detailed physics of collisionless coupling mechanisms, compliment in situ measurements of space phenomena, and provide validation of previous computational and theoretical work, the present research jointly utilizes the Large Plasma Device and the Raptor laser facility at the University of California, Los Angeles to study the super-Alfvénic, quasi-perpendicular expansion of laser-produced carbon (C) and hydrogen (H) debris plasma through preformed, magnetized helium (He) ambient plasma via a variety of diagnostics, including emission spectroscopy, wavelength-filtered imaging, and a magnetic flux probe. Doppler shifts detected in a He1+ ion spectral line indicate that the ambient ions initially accelerate transverse to both the debris plasma flow and the background magnetic field. A qualitative analysis in the framework of a "hybrid" plasma model (kinetic ions and inertia-less fluid electrons) demonstrates that the ambient ion trajectories are consistent with the large-scale laminar electric field expected to develop due to the expanding debris. In particular, the transverse ambient ion motion provides direct evidence of Larmor coupling, a collisionless momentum exchange mechanism that has received extensive theoretical and numerical investigation. In order to quantitatively evaluate the observed Doppler shifts, a custom simulation utilizing a detailed model of the laser-produced debris plasma evolution calculates the laminar electric field and computes the initial response of a distribution of ambient test ions. A synthetic Doppler

Stirling engine application study

NASA Technical Reports Server (NTRS)

Teagan, W. P.; Cunningham, D.

1983-01-01

A range of potential applications for Stirling engines in the power range from 0.5 to 5000 hp is surveyed. Over one hundred such engine applications are grouped into a small number of classes (10), with the application in each class having a high degree of commonality in technical performance and cost requirements. A review of conventional engines (usually spark ignition or Diesel) was then undertaken to determine the degree to which commercial engine practice now serves the needs of the application classes and to detemine the nature of the competition faced by a new engine system. In each application class the Stirling engine was compared to the conventional engines, assuming that objectives of ongoing Stirling engine development programs are met. This ranking process indicated that Stirling engines showed potential for use in all application classes except very light duty applications (lawn mowers, etc.). However, this potential is contingent on demonstrating much greater operating life and reliability than has been demonstrated to date by developmental Stirling engine systems. This implies that future program initiatives in developing Stirling engine systems should give more emphasis to life and reliability issues than has been the case in ongoing programs.

Advanced oxygen-hydrocarbon rocket engine study

NASA Technical Reports Server (NTRS)

Obrien, C. J.; Ewen, R. L.

1981-01-01

This study identifies and evaluates promising LO2/HC rocket engine cycles, produces a consistent and reliable data base for vehicle optimization and design studies, demonstrates the significance of propulsion system improvements, and selects the critical technology areas necessary to realize an improved surface to orbit transportation system. Parametric LO2/HC engine data were generated over a range of thrust levels from 890 to 6672 kN (200K to 1.5M 1bF) and chamber pressures from 6890 to 34500 kN (1000 to 5000 psia). Engine coolants included RP-1, refined RP-1, LCH4, LC3H8, LO2, and LH2. LO2/RP-1 G.G. cycles were found to be not acceptable for advanced engines. The highest performing LO2/RP-1 staged combustion engine cycle utilizes LO2 as the coolant and incorporates an oxidizer rich preburner. The highest performing cycle for LO2/LCH4 and LO2/LC3H8 utilizes fuel cooling and incorporates both fuel and oxidizer rich preburners. LO2/HC engine cycles permitting the use of a third fluid LH2 coolant and an LH2 rich gas generator provide higher performance at significantly lower pump discharge pressures. The LO2/HC dual throat engine, because of its high altitude performance, delivers the highest payload for the vehicle configuration that was investigated.

Study on the Characteristics of Plasma Profiles in Improved Confinement Plasmas in HT-7 Superconducting Tokamak

NASA Astrophysics Data System (ADS)

Zhang, Shouyin; Gao, Xiang; Li, Jiangang; Wan, Baonian; Kuang, Guangli; Mao, Jianshan; Zhang, Xiaodong; Xie, Jikang; Wan, Yuanxi; Team HT-7

2000-10-01

In HT-7 superconducting tokamak of circular limiter configuration (R0=122cm, a=30cm, Bt:1 ~2.2T), plasma profiles were modified and controlled by means of gas puffing, supersonic molecule injection, pellet injection, ICRF and IBW heating as well as LHW heating and current drive; improved plasma confinements were achieved either by application of one of the above measures or by the combination of them, study of the effects of the characteristics of plasma profiles on plasma confinements were performed. The results show that in most of the improved confinement plasmas in HT-7, there are very steep and strong peeking electron temperature profiles in core plasma, and/or large decrease of local temperature in radius of 0.5 ~0.7a which makes temperature gradient steeper when improvements begin, as temperature profile evolves back to previous normal shape the improvements end. Electron density profile and soft X-ray profiles were studied as well. This research was supported under Natural Science Foundation of China contract No.19905010.

Engine system assessment study using Martian propellants

NASA Technical Reports Server (NTRS)

Pelaccio, Dennis; Jacobs, Mark; Scheil, Christine; Collins, John

1992-01-01

A top-level feasibility study was conducted that identified and characterized promising chemical propulsion system designs which use two or more of the following propellant combinations: LOX/H2, LOX/CH4, and LOX/CO. The engine systems examined emphasized the usage of common subsystem/component hardware where possible. In support of this study, numerous mission scenarios were characterized that used various combinations of Earth, lunar, and Mars propellants to establish engine system requirements to assess the promising engine system design concept examined, and to determine overall exploration leverage of such systems compared to state-of-the-art cryogenic (LOX/H2) propulsion systems. Initially in the study, critical propulsion system technologies were assessed. Candidate expander and gas generator cycle LOX/H2/CO, LOX/H2/CH4, and LOX/CO/CH4 engine system designs were parametrically evaluated. From this evaluation baseline, tripropellant Mars Transfer Vehicle (MTV) LOX cooled and bipropellant Lunar Excursion Vehicle (LEV) and Mars Excursion Vehicle (MEV) engine systems were identified. Representative tankage designs for a MTV were also investigated. Re-evaluation of the missions using the baseline engine design showed that in general the slightly lower performance, smaller, lower weight gas generator cycle-based engines required less overall mission Mars and in situ propellant production (ISPP) infrastructure support compared to the larger, heavier, higher performing expander cycle engine systems.

An Experimental Study of a Pulsed Electromagnetic Plasma Accelerator

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Eskridge, Richard; Lee, Mike; Smith, James; Martin, Adam; Markusic, Tom E.; Cassibry, Jason T.; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

Experiments are being performed on the NASA Marshall Space Flight Center (MSFC) pulsed electromagnetic plasma accelerator (PEPA-0). Data produced from the experiments provide an opportunity to further understand the plasma dynamics in these thrusters via detailed computational modeling. The detailed and accurate understanding of the plasma dynamics in these devices holds the key towards extending their capabilities in a number of applications, including their applications as high power (greater than 1 MW) thrusters, and their use for producing high-velocity, uniform plasma jets for experimental purposes. For this study, the 2-D MHD modeling code, MACH2, is used to provide detailed interpretation of the experimental data. At the same time, a 0-D physics model of the plasma initial phase is developed to guide our 2-D modeling studies.

Test bed ion engine development

NASA Technical Reports Server (NTRS)

Aston, G.; Deininger, W. D.

1984-01-01

A test bed ion (TBI) engine was developed to serve as a tool in exploring the limits of electrostatic ion thruster performance. A description of three key ion engine components, the decoupled extraction and amplified current (DE-AC) accelerator system, field enhanced refractory metal (FERM) hollow cathode and divergent line cusp (DLC) discharge chamber, whose designs and operating philosophies differ markedly from conventional thruster technology is given. Significant program achievements were: (1) high current density DE-AC accelerator system operation at low electric field stress with indicated feasibility of a 60 mA/sq cm argon ion beam; (2) reliable FERM cathode start up times of 1 to 2 secs. and demonstrated 35 ampere emission levels; (3) DLC discharge chamber plasma potentials negative of anode potential; and (4) identification of an efficient high plasma density engine operating mode. Using the performance projections of this program and reasonable estimates of other parameter values, a 1.0 Newton thrust ion engine is identified as a realizable technology goal. Calculations show that such an engine, comparable in beam area to a J series 30 cm thruster, could, operating on Xe or Hg, have thruster efficiencies as high as 0.76 and 0.78 respectively, with a 100 eV/ion discharge loss.

Small Engine Component Technology (SECT) studies

NASA Technical Reports Server (NTRS)

Meyer, P. K.; Harbour, L.

1986-01-01

A study was conducted to identify component technology requirements for small, expendable gas turbine engines that would result in substantial improvements in performance and cost by the year 2000. A subsonic, 2600 nautical mile (4815 km) strategic cruise missile mission was selected for study. A baseline (state-of-the-art) engine and missile configuration were defined to evaluate the advanced technology engines. Two advanced technology engines were configured and evaluated using advanced component efficiencies and ceramic composite materials; a 22:1 overall pressure ratio, 3.85 bypass ratio twin-spool turbofan; and an 8:1 overall pressure, 3.66 bypass ratio, single-spool recuperated turbofan with 0.85 recuperator effectiveness. Results of mission analysis indicated a reduction in fuel burn of 38 and 47 percent compared to the baseline engine when using the advanced turbofan and recuperated turbofan, respectively. While use of either advanced engine resulted in approximately a 25 percent reduction in missile size, the unit life cycle (LCC) cost reduction of 56 percent for the advanced turbofan relative to the baseline engine gave it a decisive advantage over the recuperated turbofan with 47 percent LCC reduction. An additional range improvement of 10 percent results when using a 56 percent loaded carbon slurry fuel with either engine. These results can be realized only if significant progress is attained in the fields of solid lubricated bearings, small aerodynamic component performance, composite ceramic materials and integration of slurry fuels. A technology plan outlining prospective programs in these fields is presented.

Studies on Freight Train Engineer Performance

DOT National Transportation Integrated Search

1976-12-01

As a part of the International Government-Industry Program on Track Train Dynamics, the performance of engineers in freight train handling was studied by recording and analyzing train operations and engineer responses under field conditions. Data col...

Sterilization by pure oxygen plasma and by oxygen-hydrogen peroxide plasma: an efficacy study.

PubMed

Boscariol, M R; Moreira, A J; Mansano, R D; Kikuchi, I S; Pinto, T J A

2008-04-02

Plasma is an innovative sterilization method characterized by a low toxicity to operators and patients, and also by its operation at temperatures close to room temperatures. The use of different parameters for this method of sterilization and the corresponding results were analyzed in this study. A low-pressure inductive discharge was used to study the plasma sterilization processes. Oxygen and a mixture of oxygen and hydrogen peroxide were used as plasma source gases. The efficacy of the processes using different combinations of parameters such as plasma-generation method, type of gas, pressure, gas flow rate, temperature, power, and exposure time was evaluated. Two phases were developed for the processes, one using pure oxygen and the other a mixture of gases. Bacillus subtilis var. niger ATCC 9372 (Bacillus atrophaeus) spores inoculated on glass coverslips were used as biological indicators to evaluate the efficacy of the processes. All cycles were carried out in triplicate for different sublethal exposure times to calculate the D value by the enumeration method. The pour-plate technique was used to quantify the spores. D values of between 8 and 3 min were obtained. Best results were achieved at high power levels (350 and 400 W) using pure oxygen, showing that plasma sterilization is a promising alternative to other sterilization methods.

Physics of spinning gases and plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geyko, Vasily I.

Initially motivated by the problem of compression of spinning plasma in Z-pinch devices and related applications, the thesis explores a number of interesting smaller-scale problems related to physics of gas and plasma rotation. In particular, thermodynamics of ideal spinning gas is studied. It is found that rotation modifies the heat capacity of the gas and reduces the gas compressibility. It is also proposed that, by performing a series of measurement of external parameters of a spinning gas, one can infer the distribution of masses of gas constituents. It is also proposed how to use the rotation-dependent heat capacity for improvingmore » the thermodynamic efficiency of internal combustion engines. To that end, two possible engine embodiments are proposed and explored in detail. In addition, a transient piezothermal effect is discovered numerically and is given a theoretical explanation. The effect consists of the formation of a radial temperature gradient driven by gas heating or compression along the rotation axis. By elaborating on this idea, a theoretical explanation is proposed also for the operation of so-called vortex tubes, which so far have been lacking rigorous theory. Finally, adiabatic compression of spinning plasmas and ionized gases are considered, and the effect of the electrostatic interactions on the compressibility and heat capacity is predicted.« less

An airline study of advanced technology requirements for advanced high speed commercial transport engines. 1: Engine design study assessment

NASA Technical Reports Server (NTRS)

Sallee, G. P.

1973-01-01

The advanced technology requirements for an advanced high speed commercial tranport engine are presented. The results of the phase 1 study effort cover the following areas: (1) statement of an airline's major objectives for future transport engines, (2) airline's method of evaluating engine proposals, (3) description of an optimum engine for a long range subsonic commercial transport including installation and critical design features, (4) discussion of engine performance problems and experience with performance degradation, (5) trends in engine and pod prices with increasing technology and objectives for the future, (6) discussion of the research objectives for composites, reversers, advanced components, engine control systems, and devices to reduce the impact of engine stall, and (7) discussion of the airline objectives for noise and pollution reduction.

Math, Science, and Engineering Integration in a High School Engineering Course: A Qualitative Study

ERIC Educational Resources Information Center

Valtorta, Clara G.; Berland, Leema K.

2015-01-01

Engineering in K-12 classrooms has been receiving expanding emphasis in the United States. The integration of science, mathematics, and engineering is a benefit and goal of K-12 engineering; however, current empirical research on the efficacy of K-12 science, mathematics, and engineering integration is limited. This study adds to this growing…

Gasdynamic Mirror (GDM) Fusion Propulsion Engine Experiment

NASA Technical Reports Server (NTRS)

1999-01-01

The Gasdynamic Mirror, or GDM, is an example of a magnetic mirror-based fusion propulsion system. Its design is primarily consisting of a long slender solenoid surrounding a vacuum chamber that contains plasma. The bulk of the fusion plasma is confined by magnetic field generated by a series of toroidal-shaped magnets in the center section of the device. the purpose of the GDM Fusion Propulsion Experiment is to confirm the feasibility of the concept and to demonstrate many of the operational characteristics of a full-size plasma can be confined within the desired physical configuration and still reman stable. This image shows an engineer from Propulsion Research Technologies Division at Marshall Space Flight Center inspecting solenoid magnets-A, an integrate part of the Gasdynamic Mirror Fusion Propulsion Engine Experiment.

The physics of pulsed streamer discharge in high pressure air and applications to engine techonologies

NASA Astrophysics Data System (ADS)

Lin, Yung-Hsu

The goal of this dissertation is to study high pressure streamers in air and apply it to diesel engine technologies. Nanosecond scale pulsed high voltage discharges in air/fuel mixtures can generate radicals which in turn have been shown to improve combustion efficiency in gasoline fueled internal combustion engines. We are exploring the possibility to extend such transient plasma generation and expected radical species generation to the range of pressures encountered in compression-ignition (diesel) engines having compression ratios of ˜20:1, thereby improving lean burning efficiency and extending the range of lean combustion. At the beginning of this dissertation, research into streamer discharges is reviewed. Then, we conducted experiments of streamer propagation at high pressures, calculated the streamer velocity based on both optical and electrical measurements, and the similarity law was checked by analyzing the streamer velocity as a function of the reduced electric field, E/P. Our results showed that the similarity law is invalid, and an empirical scaling factor, E/√P, is obtained and verified by dimensional analysis. The equation derived from the dimensional analysis will be beneficial to proper electrode and pulse generator design for transient plasma assisted internal engine experiments. Along with the high pressure study, we applied such technique on diesel engine to improve the fuel efficiency and exhaust treatment. We observed a small effect of transient plasma on peak pressure, which implied that transient plasma has the capability to improve the fuel consumption. In addition, the NO can be reduced effectively by the same technique and the energy cost is 30 eV per NO molecule.

The Feasibility of Applying AC Driven Low-Temperature Plasma for Multi-Cycle Detonation Initiation

NASA Astrophysics Data System (ADS)

Zheng, Dianfeng

2016-11-01

Ignition is a key system in pulse detonation engines (PDE). As advanced ignition methods, nanosecond pulse discharge low-temperature plasma ignition is used in some combustion systems, and continuous alternating current (AC) driven low-temperature plasma using dielectric barrier discharge (DBD) is used for the combustion assistant. However, continuous AC driven plasmas cannot be used for ignition in pulse detonation engines. In this paper, experimental and numerical studies of pneumatic valve PDE using an AC driven low-temperature plasma igniter were described. The pneumatic valve was jointly designed with the low-temperature plasma igniter, and the numerical simulation of the cold-state flow field in the pneumatic valve showed that a complex flow in the discharge area, along with low speed, was beneficial for successful ignition. In the experiments ethylene was used as the fuel and air as oxidizing agent, ignition by an AC driven low-temperature plasma achieved multi-cycle intermittent detonation combustion on a PDE, the working frequency of the PDE reached 15 Hz and the peak pressure of the detonation wave was approximately 2.0 MPa. The experimental verifications of the feasibility in PDE ignition expanded the application field of AC driven low-temperature plasma. supported by National Natural Science Foundation of China (No. 51176001)

Bactericidal effects of plasma-modified surface chemistry of silicon nanograss

NASA Astrophysics Data System (ADS)

Ostrikov, Kola; Macgregor-Ramiasa, Melanie; Cavallaro, Alex; (Ken Ostrikov, Kostya; Vasilev, Krasimir

2016-08-01

The surface chemistry and topography of biomaterials regulate the adhesion and growth of microorganisms in ways that are still poorly understood. Silicon nanograss structures prepared via inductively coupled plasma etching were coated with plasma deposited nanometer-thin polymeric films to produce substrates with controlled topography and defined surface chemistry. The influence of surface properties on Staphylococcus aureus proliferation is demonstrated and explained in terms of nanograss substrate wetting behaviour. With the combination of the nanograss topography; hydrophilic plasma polymer coatings enhanced antimicrobial activity while hydrophobic coatings reduced it. This study advances the understanding of the effects of surface wettability on the bactericidal properties of reactive nano-engineered surfaces.

Increased coagulation and fibrinolytic potential of solvent-detergent plasma: a comparative study between Omniplasma and fresh frozen plasma.

PubMed

van Beers, J J B C; van Egmond, L T; Wetzels, R J H; Verhezen, P W M; Beckers, E A M; van Oerle, R; Spronk, H M H; Straat, R J M H E; Henskens, Y M C

2016-07-01

In this study, differences in levels of proteins involved in coagulation and fibrinolysis were compared between fresh frozen (quarantine plasma) and Omniplasma. Furthermore, thawing conditions and plasma stability after thawing were studied. 10 Omniplasma and 10 quarantine plasma units were used to study different procoagulation, anticoagulation and fibrinolytic parameters. Analysis took place at different time-points during plasma storage at 2-6°C. At baseline, significant reduced levels of factor V, free protein S, α2-antiplasmin and tPA-induced ROTEM lysis time were observed in Omniplasma as compared to quarantine plasma. Moreover, thrombin generation, IXa-AT complex levels and factor XIa were significantly increased in Omniplasma. The majority of the parameters studied remained stable in Omniplasma 48 h after thawing, with the exception of factor VIII (decrease) and IXa-AT (increase). Our results suggest an increased coagulation potential, presumingly as a result of contact activation during the production process and also, an increased fibrinolytic potential in Omniplasma. The stability of Omniplasma, based upon the different parameters studied, is comparable to Q-plasma. A maximum post-thawing time of 48 hfor Omniplasma can be suggested. © 2016 International Society of Blood Transfusion.

Space Transportation Booster Engine (STBE) configuration study

NASA Technical Reports Server (NTRS)

1986-01-01

The overall objective of this Space Transportation Booster Engine (STBE) study is to identify candidate engine configurations which enhance vehicle performance and provide operational flexibility at low cost. The specific objectives are as follows: (1) to identify and evaluate candidate LOX/HC engine configurations for the Advanced Space Transportation System for an early 1995 IOC and a late 2000 IOC; (2) to select one optimum engine for each time period; 3) to prepare a conceptual design for each configuration; (4) to develop a technology plan for the 2000 IOC engine; and, (5) to prepare preliminary programmatic planning and analysis for the 1995 IOC engine.

Orbit Transfer Vehicle (OTV) engine phase A study

NASA Technical Reports Server (NTRS)

Mellish, J. A.

1978-01-01

Requirements for the orbit transfer vehicle engine were examined. Engine performance/weight sensitivities, the effect of a service life of 300 start/shutdown cycles between overalls on the maximum engine operating pressure, and the sensitivity of the engine design point (i.e., thrust chamber pressure and nozzle area ratio) to the performance requirements specified are among the factors studied. Preliminary engine systems analyses were conducted on the stage combustion, expander, and gas generator engine cycles. Hydrogen and oxygen pump discharge pressure requirements are shown for various engine cycles. Performance of the engine cycles is compared.

Vacuum plasma coatings for turbine blades

NASA Technical Reports Server (NTRS)

Holmes, R. R.

1985-01-01

Turbine blades, vacuum plasma spray coated with NiCrAlY, CoCrAlY or NiCrAlY/Cr2O3, were evaluated and rated superior to standard space shuttle main engine (SSME) coated blades. Ratings were based primarily on 25 thermal cycles in the MSFC Burner Rig Tester, cycling between 1700 F (gaseous H2) and -423 F (liquid H2). These tests showed no spalling on blades with improved vacuum plasma coatings, while standard blades spalled. Thermal barrier coatings of ZrO2, while superior to standard coatings, lacked the overall performance desired. Fatigue and tensile specimens, machined from MAR-M-246(Hf) test bars identical to the blades were vacuum plasma spray coated, diffusion bond treated, and tested to qualify the vacuum plasma spray process for flight hardware testing and application. While NiCrAlY/Cr2O3 offers significant improvement over standard coatings in durability and thermal protection, studies continue with an objective to develop coatings offering even greater improvements.

Study of small turbofan engines applicable to single-engine light airplanes. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merrill, G.L.

1976-09-01

The design, efficiency and cost factors are investigated for application of turbofan propulsion engines to single engine, general aviation light airplanes. A companion study of a hypothetical engine family of a thrust range suitable to such aircraft and having a high degree of commonality of design features and parts is presented. Future turbofan powered light airplanes can have a lower fuel consumption, lower weight, reduced airframe maintenance requirements and improved engine overhaul periods as compared to current piston engined powered airplanes. Achievement of compliance with noise and chemical emission regulations is expected without impairing performance, operating cost or safety.

Diagnostic study of multiple double layer formation in expanding RF plasma

NASA Astrophysics Data System (ADS)

Chakraborty, Shamik; Paul, Manash Kumar; Roy, Jitendra Nath; Nath, Aparna

2018-03-01

Intensely luminous double layers develop and then expand in size in a visibly glowing RF discharge produced using a plasma source consisting of a semi-transparent cylindrical mesh with a central electrode, in a linear plasma chamber. Although RF discharge is known to be independent of device geometry in the absence of magnetic field, the initiation of RF discharge using such a plasma source results in electron drift and further expansion of the plasma in the vessel. The dynamics of complex plasma structures are studied through electric probe diagnostics in the expanding RF plasma. The measurements made to study the parametric dependence of evolution of double layer structures are analyzed and presented here. The plasma parameter measurements suggest that the complex potential structures initially form with low potential difference between the layers and then gradually expand producing burst oscillations. The present study provides interesting information about the stability of plasma sheath and charge particle dynamics in it that are important to understand the underlying basic sheath physics along with applications in plasma acceleration and propulsion.

Studies of the Plasma Triggering Mechanism of Inverse Pinch Switch

DTIC Science & Technology

1993-11-10

plasma - focus driven plasma-puff was also discussed in comparison with the hypocycloidal pinch plasma-puff triggering. The main discharge of inverse pinch switch with plasma - focus driven plasma-puff trigger is found to be more azimuthally uniform than that with hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr. A comparative study of the INPIStron and a spark gap also reveals that the INPIStron with a low impedance Z = 9 ohms can transfer a high voltage pulse with a superior pulse-shape fidelity over that with

International, prospective haemovigilance study on methylene blue-treated plasma.

PubMed

Noens, L; Vilariño, Ma D; Megalou, A; Qureshi, H

2017-05-01

Methylene blue is a phenothiazine dye, which in combination with visible light has virucidal and bactericidal properties, disrupting the replication of a broad range of enveloped viruses and some non-enveloped viruses. The study objective was to collect data on adverse reactions occurring with methylene blue plasma administered in a routine clinical practice environment and document their characteristics and severity. This was an open label, multicentre, non-controlled, non-randomized, non-interventional study. Patients who receive a methylene blue plasma transfusion were observed for any signs and symptoms (adverse reactions) within 24 h safter the start of the transfusion, in different hospitals for a study duration of at least 1 year. A total of 19 315 methylene blue plasma units were transfused. There were eight patients with adverse reactions recorded during the study, one of them serious. Two had more than one reaction (two and four, respectively). Three patients had previous transfusions with methylene blue plasma only. Methylene blue plasma has a very acceptable safety profile with a rate of serious adverse reactions of 0·5/10 000 units. © 2017 International Society of Blood Transfusion.

Study of positive and negative plasma catalytic oxidation of ethylene.

PubMed

Van Wesenbeeck, K; Hauchecorne, B; Lenaerts, S

2017-06-01

The effect of introducing a photocatalytically active coating inside a plasma unit is investigated. This technique combines the advantages of high product selectivity from catalysis and the fast start-up from plasma technology. In this study, a preselected TiO 2 coating is applied on the collector electrode of a DC corona discharge unit as non-thermal plasma reactor, in order to study the oxidation of ethylene. For both positive and negative polarities an enhanced mineralization is observed while the formation of by-products drastically decreases. The plasma catalytic unit gave the best results when using negative polarity at a voltage of 15 kV. This shows the potential of plasma catalysis as indoor air purification technology.

Engineer Examines Cluster of Ion Engines in the Electric Propulsion Laboratory

NASA Image and Video Library

1963-01-21

New staff member Paul Margosian inspects a cluster of ion engines in the Electric Propulsion Laboratory’s 25-foot diameter vacuum tank at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Lewis researchers had been studying different methods of electric rocket propulsion since the mid-1950s. Harold Kaufman created the first successful engine, the electron bombardment ion engine, in the early 1960s. These engines used electric power to create and accelerate small particles of propellant material to high exhaust velocities. Electric engines have a very small thrust, and but can operate for long periods of time. The ion engines are often clustered together to provide higher levels of thrust. The Electric Propulsion Laboratory contained two large vacuum tanks capable of simulating the space environment. The tanks were designed especially for testing ion and plasma thrusters and spacecraft. The larger 25-foot diameter tank was intended for testing electric thrusters with condensable propellants. The tank’s test compartment, seen here, was 10 feet in diameter. Margosian joined Lewis in late 1962 during a major NASA hiring phase. The Agency reorganized in 1961 and began expanding its ranks through a massive recruiting effort. Lewis personnel increased from approximately 2,700 in 1961 to over 4,800 in 1966. Margosian, who worked with Bill Kerslake in the Electromagnetic Propulsion Division’s Propulsion Systems Section, wrote eight technical reports on mercury and electron bombardment thrusters, thermoelectrostatic generators, and a high voltage insulator.

Emission characteristics of kerosene-air spray combustion with plasma assistance

NASA Astrophysics Data System (ADS)

Liu, Xingjian; He, Liming; Zeng, Hao; Jin, Tao; Chen, Yi; Zhang, Yihan; Liu, Pengfei

2015-09-01

A plasma assisted combustion system for combustion of kerosene-air mixtures was developed to study emission levels of O2, CO2, CO, and NOx. The emission measurement was conducted by Testo 350-Pro Flue Gas Analyzer. The effect of duty ratio, feedstock gas flow rate and applied voltage on emission performance has been analyzed. The results show that O2 and CO emissions reduce with an increase of applied voltage, while CO2 and NOx emissions increase. Besides, when duty ratio or feedstock gas flow rate decreases, the same emission results would appear. The emission spectrum of the air plasma of plasma assisted combustion actuator was also registered to analyze the kinetic enhancement effect of plasma, and the generation of ozone was believed to be the main factor that plasma makes a difference in our experiment. These results are valuable for the future optimization of kerosene-fueled aircraft engine when using plasma assisted combustion devices to exert emission control.

Advanced stratified charge rotary aircraft engine design study

NASA Technical Reports Server (NTRS)

Badgley, P.; Berkowitz, M.; Jones, C.; Myers, D.; Norwood, E.; Pratt, W. B.; Ellis, D. R.; Huggins, G.; Mueller, A.; Hembrey, J. H.

1982-01-01

A technology base of new developments which offered potential benefits to a general aviation engine was compiled and ranked. Using design approaches selected from the ranked list, conceptual design studies were performed of an advanced and a highly advanced engine sized to provide 186/250 shaft Kw/HP under cruise conditions at 7620/25,000 m/ft altitude. These are turbocharged, direct-injected stratified charge engines intended for commercial introduction in the early 1990's. The engine descriptive data includes tables, curves, and drawings depicting configuration, performance, weights and sizes, heat rejection, ignition and fuel injection system descriptions, maintenance requirements, and scaling data for varying power. An engine-airframe integration study of the resulting engines in advanced airframes was performed on a comparative basis with current production type engines. The results show airplane performance, costs, noise & installation factors. The rotary-engined airplanes display substantial improvements over the baseline, including 30 to 35% lower fuel usage.

Multiprobe characterization of plasma flows for space propulsion

NASA Astrophysics Data System (ADS)

Damba, Julius; Argente, P.; Maldonado, P. E.; Cervone, A.; Domenech-Garret, J. L.; Conde, L.

2018-02-01

Plasma engines for space propulsion generate plasma jets (also denominated plasma plumes) having supersonic ion groups with typical speeds in the order of tens of kilometers per second, which lies between electron and ion thermal speeds. Studies of the stationary plasma expansion process using a four-grid retarding field energy analyzer (RFEA), an emissive probe (EP) and a Langmuir probe (LP), all mounted on a three dimensionally (3D) displaced multiprobe structure are discussed. Specifically, the determination of plasma beam properties from the RFEA current-voltage (IV) characteristic curves is presented. The experimental results show the ion energy spectra to be essentially unchanged over 300 mm along the plasma-jet expansion axis of symmetry. The measured ion velocity distribution function (IVDF) results from the superposition of different ion groups and has two dominant populations: A low-energy group constituted of ions from the background plasma is produced by the interaction of the plasma jet with the walls of the vacuum chamber. The fast-ion population is composed of ions from the plasma beam moving at supersonic speeds with respect to the low-energy ions. The decreasing spatial profiles of the plasma-jet current density are compared with those of the low-energy ion group, which are not uniform along the axis of symmetry because of the small contributions from other ion populations with intermediate speeds.

Enhancing Systems Engineering Education Through Case Study Writing

NASA Technical Reports Server (NTRS)

Stevens, Jennifer Stenger

2016-01-01

Developing and refining methods for teaching systems engineering is part of Systems Engineering grand challenges and agenda for research in the SE research community. Retention of systems engineering knowledge is a growing concern in the United States as the baby boom generation continues to retire and the faster pace of technology development does not allow for younger generations to gain experiential knowledge through years of practice. Government agencies, including the National Aeronautics and Space Administration (NASA), develop their own curricula and SE leadership development programs to "grow their own" systems engineers. Marshall Space Flight Center (MSFC) conducts its own Center-focused Marshall Systems Engineering Leadership Development Program (MSELDP), a competitive program consisting of coursework, a guest lecture series, and a rotational assignment into an unfamiliar organization engaged in systems engineering. Independently, MSFC developed two courses to address knowledge retention and sharing concerns: Real World Marshall Mission Success course and its Case Study Writers Workshop and Writers Experience. Teaching case study writing and leading students through a hands-on experience at writing a case study on an SE topic can enhance SE training and has the potential to accelerate the transfer of experiential knowledge. This paper is an overview of the pilot experiences with teaching case study writing, its application in case study-based learning, and identifies potential areas of research and application for case study writing in systems engineering education.

Oregon Pre-Engineering Learning Outcomes Study: Final Report

ERIC Educational Resources Information Center

Conley, David T.; Langan, Holly; Veach, Darya; Farkas, Virginia

2007-01-01

The Oregon Pre-engineering Learning Outcomes Project was conducted by the Educational Policy Improvement Center (EPIC) with grant funding from the Engineering and Technology Industry Council (ETIC). The study sought to improve student preparation and success in pre-engineering programs through the development of the Oregon Pre-engineering Learning…

Plasma–wall interaction studies within the EUROfusion consortium: progress on plasma-facing components development and qualification

DOE PAGES

Brezinsek, S.; Coenen, J. W.; Schwarz-Selinger, T.; ...

2017-06-14

The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, andmore » by modelling codes that simulate edge-plasma conditions and the plasma–material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in

Plasma–wall interaction studies within the EUROfusion consortium: progress on plasma-facing components development and qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brezinsek, S.; Coenen, J. W.; Schwarz-Selinger, T.

The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, andmore » by modelling codes that simulate edge-plasma conditions and the plasma–material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in

Jet Engines as High-Capacity Vacuum Pumps

NASA Technical Reports Server (NTRS)

Wojciechowski, C. J.

1983-01-01

Large diffuser operations envelope and long run times possible. Jet engine driven ejector/diffuser system combines two turbojet engines and variable-area-ratio ejector in two stages. Applications in such industrial proesses as handling corrosive fumes, evaporation of milk and fruit juices, petroleum distillation, and dehydration of blood plasma and penicillin.

Nanocarbon materials fabricated using plasmas

NASA Astrophysics Data System (ADS)

Hatakeyama, Rikizo

2017-12-01

Since the discovery of fullerenes more than three decades ago, new kinds of nanoscale materials of carbon allotropes called "nanocarbons" have so far been discovered or synthesized at successive intervals as cases such as carbon nanotubes, carbon nanohorns, graphene, carbon nanowalls, and a carbon nanobelt, while nanodiamonds were actually discovered before then. Their attractively excellent mechanical, physical, and chemical properties have driven researchers to continuously create one of the hottest frontiers in materials science and technology. While plasma states have often been involved in their discovery, on the other hand, plasma-based approaches to this exciting field originally hold promising and enormous potentials for advancing and expanding industrial/biomedical applications of nanocarbons of great diversity. This article provides an extensive overview on plasma-fabricated nanocarbon materials, where the term "fabrication" is defined as synthesis, functionalization, and assembly of devices to cover a wide range of issues associated with the step-by-step plasma processes. Specific attention has been paid to the comparative examination between plasma-based and non-plasma methods for fabricating the nanocarobons with an emphasis on the advantages of plasma processing, such as low-temperature/large-scale fabrication and diversity-carrying structure controllability. The review ends with current challenges and prospects including a ripple effect of the nanocarbon studies on the development of related novel nanomaterials such as transition metal dichalcogenides. It contains not only the latest progress in the field for cutting-edge scientists and engineers, but also the introductory guidance to non-specialists such as lower-class graduate students.

Plasma contactor development for Space Station

NASA Technical Reports Server (NTRS)

Patterson, Michael J.; Hamley, John A.; Sarmiento, Charles J.; Manzella, David H.; Sarver-Verhey, Timothy; Soulas, George C.; Nelson, Amy

1993-01-01

Plasma contactors have been baselined for the Space Station (SS) to control the electrical potentials of surfaces to eliminate/mitigate damaging interactions with the space environment. The system represents a dual-use technology which is a direct outgrowth of the NASA electric propulsion program and, in particular, the technology development effort on ion thrustor systems. The plasma contactor subsystems include the plasma contactor unit, a power electronics unit, and an expellant management unit. Under this pre-flight development program these will all be brought to breadboard or engineering model status. Development efforts for the plasma contactor include optimizing the design and configuration of the contactor, validating its required lifetime, and characterizing the contactor plume and electromagnetic interference. The plasma contactor unit design selected for the SS is an enclosed keeper, xenon hollow cathode plasma source. This paper discusses the test results and development status of the plasma contactor unit subsystem for the SS.

Plasma contactor development for Space Station

NASA Astrophysics Data System (ADS)

Patterson, Michael J.; Hamley, John A.; Sarmiento, Charles J.; Manzella, David H.; Sarver-Verhey, Timothy; Soulas, George C.; Nelson, Amy

1993-12-01

Plasma contactors have been baselined for the Space Station (SS) to control the electrical potentials of surfaces to eliminate/mitigate damaging interactions with the space environment. The system represents a dual-use technology which is a direct outgrowth of the NASA electric propulsion program and, in particular, the technology development effort on ion thrustor systems. The plasma contactor subsystems include the plasma contactor unit, a power electronics unit, and an expellant management unit. Under this pre-flight development program these will all be brought to breadboard or engineering model status. Development efforts for the plasma contactor include optimizing the design and configuration of the contactor, validating its required lifetime, and characterizing the contactor plume and electromagnetic interference. The plasma contactor unit design selected for the SS is an enclosed keeper, xenon hollow cathode plasma source. This paper discusses the test results and development status of the plasma contactor unit subsystem for the SS.

Plasma Physics Applied (New Book)

NASA Astrophysics Data System (ADS)

Grabbe, Crockett

2007-03-01

0.5cm Plasma physics applications are one of the most rapidly growing fields in engineering & applied science today. The last decade alone has seen the rapid emergence of new applications such as dusty plasmas in the semiconductor and microchip industries, and plasma TVs. In addition, this last decade saw the achievement of the 50-year Lawson breakeven condition for fusion. With new discoveries in space plasma physics and applications to spacecraft for worldwide communication and space weather, as well as new applications being discovered, this diversity is always expanding. The new book Plasma Physics Applied reviews developments in several of these areas. Chapter 1 reviews the content and its authors, and is followed by a more comprehensive review of plasma physics applications in general in Chapter 2. Plasma applications in combustion and environmental uses are presented in Chapter 3. Lightning effects in planetary magnetospheres and potential application are described in Chapter 4. The area of dusty plasmas in both industrial and space plasmas and their applications are reviewed in Chapter 5. The particular area of Coulomb clusters in dusty plasmas is presented in Chapter 6. The variety of approaches to plasma confinement in magnetic devices for fusion are laid out in Chapter 7. Finally, an overview of plasma accelerator developments and their applications are presented in Chapter 8.

Fundamental Studies of Transient, Atmospheric-Pressure, Small-Scale Plasmas

DTIC Science & Technology

2017-01-23

e.g. plasma brush) were explored for surface decontamination against pathogenic bacteria and biofilms , as well as for treatment of cervical cancer , in...pressure plasma jets and jet arrays (e.g. plasma brush) were explored for surface decontamination against pathogenic bacteria and biofilms , as well as...for treatment of cervical cancer , in vitro. 4) Other studies involving portable nanosecond pulsed power generation based gas switches or

A plasma lens for a linear collider final focus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norem, J.; Cline, D.B.; Cole, B.

High density relativistic beams propagating in a plasma are affected by fields induced by plasma motion. We consider the possible use of a plasma cell very close to the interaction point of a linear collider where the self-pinch induced in the relativistic beams can be used to increase the luminosity of colliding beams. We describe the benefits of this self-pinch, as well as some engineering details on the production of the required plasma. 18 refs., 5 figs., 1 tab.

Studies of particle wake potentials in plasmas

NASA Astrophysics Data System (ADS)

Ellis, Ian N.; Graziani, Frank R.; Glosli, James N.; Strozzi, David J.; Surh, Michael P.; Richards, David F.; Decyk, Viktor K.; Mori, Warren B.

2011-09-01

A detailed understanding of electron stopping and scattering in plasmas with variable values for the number of particles within a Debye sphere is still not at hand. Presently, there is some disagreement in the literature concerning the proper description of these processes. Theoretical models assume electrostatic (Coulomb force) interactions between particles and neglect magnetic effects. Developing and validating proper descriptions requires studying the processes using first-principle plasma simulations. We are using the particle-particle particle-mesh (PPPM) code ddcMD and the particle-in-cell (PIC) code BEPS to perform these simulations. As a starting point in our study, we examine the wake of a particle passing through a plasma in 3D electrostatic simulations performed with ddcMD and BEPS. In this paper, we compare the wakes observed in these simulations with each other and predictions from collisionless kinetic theory. The relevance of the work to Fast Ignition is discussed.

Advanced automotive diesel engine system study

NASA Technical Reports Server (NTRS)

1983-01-01

A conceptual study of an advanced automotive diesel engine is discussed. The engine concept selected for vehicle installation was a supercharged 1.4 liter, 4 cylinder spark assisted diesel of 14:1 compression ratio. A compounding unit consisting of a Lysholm compressor and expander is connected to the engine crankshaft by a belt drive. The inlet air charge is heated by the expander exhaust gas via a heat exchanger. Four levels of technology achievement on the selected engine concept were evaluated, from state-of-the-art to the ideal case. This resulted in the fuel economy increasing from 53.2 mpg to 81.7 mpg, and the 0-60 mph time decreasing from 17.6 seconds to 10.9 seconds.

Screening studies of advanced control concepts for airbreathing engines

NASA Technical Reports Server (NTRS)

Ouzts, Peter J.; Lorenzo, Carl F.; Merrill, Walter C.

1993-01-01

The application of advanced control concepts to airbreathing engines may yield significant improvements in aircraft/engine performance and operability. Accordingly, the NASA Lewis Research Center has conducted screening studies of advanced control concepts for airbreathing engines to determine their potential impact on turbine engine performance and operability. The purpose of the studies was to identify concepts which offered high potential yet may incur high research and development risk. A target suite of proposed concepts was formulated by NASA and industry. These concepts were evaluated in a two phase study to quantify each concept's impact on desired engine characteristics. To aid in the evaluation, three target aircraft/engine combinations were considered: a military high performance fighter mission, a high speed civil transport mission, and a civil tiltrotor mission. Each of the advanced control concepts considered in the study were defined and described. The concept's potential impact on engine performance was determined. Relevant figures of merit on which to evaluate the concepts were also determined. Finally, the concepts were ranked with respect to the target aircraft/engine missions.

Studies of Plasma-Sprayed Alumina

NASA Astrophysics Data System (ADS)

Ilavsky, Jan

1994-05-01

Phase transformations and porosity of the plasma sprayed alumina deposits were examined. The dependence of the phase transformations on deposit chemistry was established. Porosity changes during heat treatment were studied and a model for the porosity is proposed. A novel technique in the field of plasma sprayed deposits--small-angle neutron scattering (SANS)--was successfully applied. Deposits were manufactured using the water-stabilized plasma spray system, PAL160, with an input of 160 kW. Phase transformations of the plasma sprayed alumina deposits were studied using XRD and DTA. The deposits were manufactured from 99.9% alumina, alumina-chromia (1.5% Cr_2O_3), gray alumina (3.7% TiO_2) and alumina -titania (17% TiO_2). The addition of chromia increases the temperature of the alpha phase formation by about 40^circ C and the addition of TiO_2 reduces this temperature by about 150^circ C for gray alumina and by about 175^ circC for alumina-titania. The amount of metastable theta phase was found to depend on the chemistry of the feedstock. Porosities of the deposits, made from alumina and gray alumina, were studied using mercury intrusion porosimetry, weighing method (Archimedean porosimetry), image analysis and SANS. Samples were studied in the as -sprayed condition and after heat treatment for 2 hours at 1300^circC and 1500 ^circC. Porosity depends on the deposit chemistry and on the heat treatment and varies from 5% to about 11%. Different porosity measurement techniques yield different results. Surface areas of 1.5 to 7.5 times 10^4 cm^2 /cm^3 (times 10^6 m^{ -1}) were measured using SANS and depend on heat treatment and on the deposit chemistry. The phase transformations can be associated with an increase in pore surface area and decrease in surface area at 1500 ^circC can be associated with sintering. The effective pore radius, R_{ rm eff}, as measured by SANS is a measure of the pore sizes in the 0.08 to 10 μm size range. The R_{rm eff} depends on deposit

Patients' quality of life after stopping plasma exchange: a pilot study.

PubMed

Dahlan, Randah; McCormick, Brendan B; Alkhattabi, Maan; Gallo, Kerri; Clark, William F; Rock, Gail

2014-10-01

Plasma exchange is being widely used to treat various serious medical conditions. There has been very little follow-up data to describe the quality of life (QOL) of plasma exchange-recipients after active plasma exchange has stopped. To assess the QOL of plasma exchange recipients after stopping plasma exchange. A pilot study, based on responses to a postal questionnaire and clinical data obtained from the patients' charts, was carried out. The scores were computed from questionnaire responses and analyzed. The response rate was 59% with 58 patients completing a questionnaire three months after their final plasma exchange therapy. We identified significant heterogeneity in the quality of life of plasma exchange recipients after stopping plasma exchange therapy. This could be driven by different patient co-morbidities. We recommend that during follow up visits, a multi-disciplinary approach including consultation with a social worker might be considered for patients who may continue to have some limitations in their psychosocial activities post-discontinuation of plasma exchange. The high response rate to the questionnaire indicates that PLEX patients are interested in being involved in QOL studies, which suggests potential support for a prospective study of QOL with pre and post questionnaires and more detailed tracking of baseline co-morbidities. Copyright © 2014 Elsevier Ltd. All rights reserved.

Intelligent Life-Extending Controls for Aircraft Engines Studied

NASA Technical Reports Server (NTRS)

Guo, Ten-Huei

2005-01-01

Current aircraft engine controllers are designed and operated to provide desired performance and stability margins. Except for the hard limits for extreme conditions, engine controllers do not usually take engine component life into consideration during the controller design and operation. The end result is that aircraft pilots regularly operate engines under unnecessarily harsh conditions to strive for optimum performance. The NASA Glenn Research Center and its industrial and academic partners have been working together toward an intelligent control concept that will include engine life as part of the controller design criteria. This research includes the study of the relationship between control action and engine component life as well as the design of an intelligent control algorithm to provide proper tradeoffs between performance and engine life. This approach is expected to maintain operating safety while minimizing overall operating costs. In this study, the thermomechanical fatigue (TMF) of a critical component was selected to demonstrate how an intelligent engine control algorithm can significantly extend engine life with only a very small sacrifice in performance. An intelligent engine control scheme based on modifying the high-pressure spool speed (NH) was proposed to reduce TMF damage from ground idle to takeoff. The NH acceleration schedule was optimized to minimize the TMF damage for a given rise-time constraint, which represents the performance requirement. The intelligent engine control scheme was used to simulate a commercial short-haul aircraft engine.

Synthetic Plasma Liquid Based Electronic Circuits Realization-A Novel Concept.

PubMed

Pandya, Killol V; Kosta, ShivPrasad

2016-09-01

Biomedical research is contributing significant role in the field of biomedical engineering and applied science. It brings research and innovations to a different level. This study investigated artificial human blood -synthetic plasma liquid as conductive medium. Keeping in mind the conductivity of synthetic plasma, astable multivibrator as well as differential amplifier circuit were demonstrated. The circuits were given normal input voltages at regular temperature and ideal conditions. The result shows desired response which supports the novel concept. For both the circuits, phase shift of 180° achieved by analysing biological electronic circuits.

Studies of the air plasma spraying of zirconia powder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varacalle, D.J. Jr.; Wilson, G.C.; Crawmer, D.E.

As part of an investigation of the dynamics that occur in the air plasma spray process, an experimental and analytical study has been accomplished for the deposition of yttria-stabilized zirconia powder using argon-hydrogen and argon-helium working gases. Numerical models of the plasma dynamics and the related plasma-particle interaction are presented. The analytical studies were conducted to determine the parameter space for the empirical studies. Experiments were then conducted using a Box statistical design-of-experiment approach. A substantial range of plasma processing conditions and their effect on the resultant coating is presented. The coatings were characterized by hardness tests and optical metallographymore » (i.e., image analysis). Coating qualities are discussed with respect to hardness, porosity, surface roughness, deposition efficiency, and microstructure. Attributes of the coatings are correlated with the changes in operating parameters. An optimized coating design predicted by the SDE analysis and verified by the calculations is also presented.« less

A study of airplane engine tests

NASA Technical Reports Server (NTRS)

Gage, Victor R

1920-01-01

This report is a study of the results obtained from a large number of test of an Hispano-Suiza airplane engine in the altitude laboratory of the Bureau of Standards. It was originally undertaken to determine the heat distribution in such an engine, but many other factors are also considered as bearing on this matter.

Studies of Plasma Instabilities using Unstructured Discontinuous Galerkin Method with the Two-Fluid Plasma Model

NASA Astrophysics Data System (ADS)

Song, Yang; Srinivasan, Bhuvana

2017-10-01

The discontinuous Galerkin (DG) method has the advantage of resolving shocks and sharp gradients that occur in neutral fluids and plasmas. An unstructured DG code has been developed in this work to study plasma instabilities using the two-fluid plasma model. Unstructured meshes are known to produce small and randomized grid errors compared to traditional structured meshes. Computational tests for Rayleigh-Taylor instabilities in radially-converging flows are performed using the MHD model. Choice of grid geometry is not obvious for simulations of instabilities in these circular configurations. Comparisons of the effects for different grids are made. A 2D magnetic nozzle simulation using the two-fluid plasma model is also performed. A vacuum boundary condition technique is applied to accurately solve the Riemann problem on the edge of the plume.

Raman spectroscopic study of plasma-treated salmon DNA

NASA Astrophysics Data System (ADS)

Joon Lee, Geon; Kwon, Young-Wan; Hee Kim, Yong; Ha Choi, Eun

2013-01-01

In this research, we studied the effect of plasma treatment on the optical/structural properties of the deoxyribonucleic acid (DNA) extracted from salmon sperm. DNA-cetyltrimethylammonium (CTMA) films were obtained by complexation of DNA with CTMA. Circular dichroism (CD) and Raman spectra indicated that DNA retained its double helical structure in the solid film. The Raman spectra exhibited several vibration modes corresponding to the nuclear bases and the deoxyribose-phosphate backbones of the DNA, as well as the alkylchains of CTMA. Dielectric-barrier-discharge (DBD) plasma treatment induced structural modification and damage to the DNA, as observed by changes in the ultraviolet-visible absorption, CD, and Raman spectra. The optical emission spectra of the DBD plasma confirmed that DNA modification was induced by plasma ions such as reactive oxygen species and reactive nitrogen species.

Orbital Transfer Vehicle (OTV) engine study. Phase A: Extension

NASA Technical Reports Server (NTRS)

Sobin, A. J.

1980-01-01

The current Phase A-Extension of the OTV engine study program aims to provide additional expander and staged combustion cycle data that will lead to design definition of the OTV engine. The proposed program effort seeks to optimize the expander cycle engine concept (consistent with identified OTV engine requirements), investigate the feasibility of kitting the staged combustion cycle engine to provide extended thrust operation, and conduct in-depth analysis of development risk, crew safety, and reliability for both cycles. Additional tasks address the costing of a 10/K thrust expander cycle engine and support of OTV systems study contractors.

Developing Tomorrows Engineers: A Case Study in Instrument Engineering

ERIC Educational Resources Information Center

McDonnell, Liam; O'Neill, Donal

2009-01-01

Purpose: The purpose of this case study is to outline the challenges facing industry and educational institutions in educating and training instrument engineers against a backdrop of declining interest by secondary school students in mathematics and physics. This case study cites the experience and strategies of the Kentz Group and Cork Institute…

Autologous human plasma in stem cell culture and cryopreservation in the creation of a tissue-engineered vascular graft.

PubMed

Zhang, Ping; Policha, Aleksandra; Tulenko, Thomas; DiMuzio, Paul

2016-03-01

Previous work demonstrated the effectiveness of autologous adipose-derived stem cells (ASCs) as endothelial cell (EC) substitutes in vascular tissue engineering. We further this work toward clinical translation by evaluating ASC function after (1) replacement of fetal bovine serum (FBS) with autologous human plasma (HP) in culture and (2) cryopreservation. Human ASCs and plasma, isolated from periumbilical fat and peripheral blood, respectively, were collected from the same donors. ASCs were differentiated in endothelial growth medium supplemented with FBS (2%) vs HP (2%). Proliferation was measured by growth curves and MTT assay. Endothelial differentiation was measured by quantitative polymerase chain reaction, assessment of acetylated low-density lipoprotein uptake, and cord formation after plating on Matrigel (BD Biosciences, San Jose, Calif). Similar studies were conducted before and after cryopreservation of ASCs and included assessment of cell retention on the luminal surface of a vascular graft. ASCs expanded in HP-supplemented medium showed (1) similar proliferation to FBS-cultured ASCs, (2) consistent differentiation toward an EC lineage (increases in CD31, von Willebrand factor, and CD144 message; acetylated low-density lipoprotein uptake; and cord formation on Matrigel), and (3) retention on the luminal surface after seeding and subsequent flow conditioning. Cryopreservation did not significantly alter ASC viability, proliferation, acquisition of endothelial characteristics, or retention after seeding onto a vascular graft. This study suggests that (1) replacement of FBS with autologous HP--a step necessary for the translation of this technology into human use--does not significantly impair proliferation or endothelial differentiation of ASCs used as EC substitutes and (2) ASCs are tolerant to cryopreservation in terms of maintaining EC characteristics and retention on a vascular graft. Copyright © 2016 Society for Vascular Surgery. Published by

Platelet-Rich Plasma in Bone Regeneration: Engineering the Delivery for Improved Clinical Efficacy

PubMed Central

Rodriguez, Isaac A.; Growney Kalaf, Emily A.; Bowlin, Gary L.; Sell, Scott A.

2014-01-01

Human bone is a tissue with a fairly remarkable inherent capacity for regeneration; however, this regenerative capacity has its limitations, and defects larger than a critical size lack the ability to spontaneously heal. As such, the development and clinical translation of effective bone regeneration modalities are paramount. One regenerative medicine approach that is beginning to gain momentum in the clinical setting is the use of platelet-rich plasma (PRP). PRP therapy is essentially a method for concentrating platelets and their intrinsic growth factors to stimulate and accelerate a healing response. While PRP has shown some efficacy in both in vitro and in vivo scenarios, to date its use and delivery have not been optimized for bone regeneration. Issues remain with the effective delivery of the platelet-derived growth factors to a localized site of injury, the activation and temporal release of the growth factors, and the rate of growth factor clearance. This review will briefly describe the physiological principles behind PRP use and then discuss how engineering its method of delivery may ultimately impact its ability to successfully translate to widespread clinical use. PMID:25050347

Photon Physics and Plasma Research, Photonics Applications and Web Engineering, Wilga, May 2012

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.

2012-05-01

This paper is the third part (out of five) of the research survey of WILGA Symposium work, May 2012 Edition, concerned with Photon Physics and Plasma Research. It presents a digest of chosen technical work results shown by young researchers from different technical universities from this country during the Jubilee XXXth SPIE-IEEE Wilga 2012, May Edition, symposium on Photonics and Web Engineering. Topical tracks of the symposium embraced, among others, nanomaterials and nanotechnologies for photonics, sensory and nonlinear optical fibers, object oriented design of hardware, photonic metrology, optoelectronics and photonics applications, photonics-electronics co-design, optoelectronic and electronic systems for astronomy and high energy physics experiments, JET tokamak and pi-of-the sky experiments development. The symposium is an annual summary in the development of numerable Ph.D. theses carried out in this country in the area of advanced electronic and photonic systems. It is also a great occasion for SPIE, IEEE, OSA and PSP students to meet together in a large group spanning the whole country with guests from this part of Europe. A digest of Wilga references is presented [1-270].

Non-thermal plasma technology for the development of antimicrobial surfaces: a review

NASA Astrophysics Data System (ADS)

Nikiforov, Anton; Deng, Xiaolong; Xiong, Qing; Cvelbar, U.; DeGeyter, N.; Morent, R.; Leys, Christophe

2016-05-01

Antimicrobial coatings are in high demand in many fields including the biomaterials and healthcare sectors. Within recent progress in nanoscience and engineering at the nanoscale, preparation of nanocomposite films containing metal nanoparticles (such as silver nanoparticles, copper nanoparticles, zinc oxide nanoparticles) is becoming an important step in manufacturing biomaterials with high antimicrobial activity. Controlled release of antibiotic agents and eliminating free nanoparticles are of equal importance for engineering antimicrobial nanocomposite materials. Compared to traditional chemical ‘wet’ methods, plasma deposition and plasma polymerization are promising approaches for the fabrication of nanocomposite films with the advantages of gas phase dry processes, effective use of chemicals and applicability to various substrates. In this article, we present a short overview of state-of-the-art engineering of antimicrobial materials based on the use of non-thermal plasmas at low and atmospheric pressure.

Exoskeletal Engine Concept: Feasibility Studies for Medium and Small Thrust Engines

NASA Technical Reports Server (NTRS)

Halliwell, Ian

2001-01-01

The exoskeletal engine concept is one in which the shafts and disks are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Omission of the shafts and disks leads to an open channel at the engine centerline. This has immense potential for reduced jet noise and for the accomodation of an alternative form of thruster for use in a combined cycle. The use of ceramic composite materials has the potential for significantly reduced weight as well as higher working temperatures without cooling air. The exoskeletal configuration is also a natural stepping-stone to complete counter-rotating turbomachinery. Ultimately this will lead to reductions in weight, length, parts count and improved efficiency. The feasibility studies are in three parts. Part I-Systems and Component Requirements addressed the mechanical aspects of components from a functionality perspective. This effort laid the groundwork for preliminary design studies. Although important, it is not felt to be particularly original, and has therefore not been included in the current overview. Part 2-Preliminary Design Studies turned to some of the cycle and performance issues inherent in an exoskeletal configuration and some initial attempts at preliminary design of turbomachinery were described. Twin-spoon and single-spool 25.800-lbf-thrust turbofans were used as reference vehicles in a mid-size commercial subsonic category in addition to a single-spool 5,000-lbf-thrust turbofan that represented a general aviation application. The exoskeletal engine, with its open centerline, has tremendous potential for noise suppression and some preliminary analysis was done which began to quantify the benefits. Part 3-Additional Preliminary Design Studies revisited the design of single-spool 25,800-lbf-thrust turbofan configurations, but in addition to the original FPR = 1.6 and BPR = 5.1 reference engine, two additional configurations used FPR = 2.4 and BPR = 3.0 and FPR = 3.2 and BPR

Exoskeletal Engine Concept: Feasibility Studies for Medium and Small Thrust Engines

NASA Technical Reports Server (NTRS)

Halliwell, Ian

2001-01-01

The exoskeletal engine concept is one in which the shafts and disks are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Omission of the shafts and disks leads to an open channel at the engine centerline. This has immense potential for reduced jet noise and for the accommodation of an alternative form of thruster for use in a combined cycle. The use of ceramic composite materials has the potential for significantly reduced weight as well as higher working temperatures without cooling air. The exoskeletal configuration is also a natural stepping-stone to complete counter-rotating turbomachinery. Ultimately this will lead to reductions in weight, length, parts count and improved efficiency. The feasibility studies are in three parts. Part 1: Systems and Component Requirements addressed the mechanical aspects of components from a functionality perspective. This effort laid the groundwork for preliminary design studies. Although important, it is not felt to be particularly original, and has therefore not been included in the current overview. Part 2: Preliminary Design Studies turned to some of the cycle and performance issues inherent in an exoskeletal configuration and some initial attempts at preliminary design of turbomachinery were described. Twin-spoon and single-spool 25,800-lbf-thrust turbofans were used as reference vehicles in a mid-size commercial subsonic category in addition to a single-spool 5,000-lbf-thrust turbofan that represented a general aviation application. The exoskeletal engine, with its open centerline, has tremendous potential for noise suppression and some preliminary analysis was done which began to quantify the benefits. Part 3: Additional Preliminary Design Studies revisited the design of single-spool 25,800-lbf-thrust turbofan configurations, but in addition to the original FPR = 1.6 and BPR = 5.1 reference engine. two additional configurations used FPR = 2.4 and BPR = 3.0 and FPR = 3.2 and

Guest investigator program study: Physics of equatorial plasma bubbles

NASA Technical Reports Server (NTRS)

Tsunoda, Roland T.

1994-01-01

Plasma bubbles are large-scale (10 to 100 km) depletions in plasma density found in the night-time equatorial ionosphere. Their formation has been found to entail the upward transport of plasma over hundreds of kilometers in altitude, suggesting that bubbles play significant roles in the physics of many of the diverse and unique features found in the low-latitude ionosphere. In the simplest scenario, plasma bubbles appear first as perturbations in the bottomside F layer, which is linearly unstable to the gravitationally driven Rayleigh-Taylor instability. Once initiated, bubbles develop upward through the peak of the F layer into its topside (sometimes to altitudes in excess of 1000 km), a behavior predicted by the nonlinear form of the same instability. While good general agreement has been found between theory and observations, little is known about the detailed physics associated with plasma bubbles. Our research activity centered around two topics: the shape of plasma bubbles and associated electric fields, and the day-to-day variability in the occurrence of plasma bubbles. The first topic was pursued because of a divergence in view regarding the nonlinear physics associated with plasma bubble development. While the development of perturbations in isodensity contours in the bottomside F layer into plasma bubbles is well accepted, some believed bubbles to be cylinder-like closed regions of depleted plasma density that floated upward leaving a turbulent wake behind them (e.g., Woodman and LaHoz, 1976; Ott, 1978; Kelley and Ott, 1978). Our results, summarized in a paper submitted to the Journal of Geophysical Research, consisted of incoherent scatter radar measurements that showed unambiguously that the depleted region is wedgelike and not cylinderlike, and a case study and modeling of SM-D electric field instrument (EFI) measurements that showed that the absence of electric-field perturbations outside the plasma-depleted region is a distinct signature of wedge

Advanced general aviation comparative engine/airframe integration study

NASA Technical Reports Server (NTRS)

Huggins, G. L.; Ellis, D. R.

1981-01-01

The NASA Advanced Aviation Comparative Engine/Airframe Integration Study was initiated to help determine which of four promising concepts for new general aviation engines for the 1990's should be considered for further research funding. The engine concepts included rotary, diesel, spark ignition, and turboprop powerplants; a conventional state-of-the-art piston engine was used as a baseline for the comparison. Computer simulations of the performance of single and twin engine pressurized aircraft designs were used to determine how the various characteristics of each engine interacted in the design process. Comparisons were made of how each engine performed relative to the others when integrated into an airframe and required to fly a transportation mission.

Microwave-Assisted Ignition for Improved Internal Combustion Engine Efficiency

NASA Astrophysics Data System (ADS)

DeFilippo, Anthony Cesar

The ever-present need for reducing greenhouse gas emissions associated with transportation motivates this investigation of a novel ignition technology for internal combustion engine applications. Advanced engines can achieve higher efficiencies and reduced emissions by operating in regimes with diluted fuel-air mixtures and higher compression ratios, but the range of stable engine operation is constrained by combustion initiation and flame propagation when dilution levels are high. An advanced ignition technology that reliably extends the operating range of internal combustion engines will aid practical implementation of the next generation of high-efficiency engines. This dissertation contributes to next-generation ignition technology advancement by experimentally analyzing a prototype technology as well as developing a numerical model for the chemical processes governing microwave-assisted ignition. The microwave-assisted spark plug under development by Imagineering, Inc. of Japan has previously been shown to expand the stable operating range of gasoline-fueled engines through plasma-assisted combustion, but the factors limiting its operation were not well characterized. The present experimental study has two main goals. The first goal is to investigate the capability of the microwave-assisted spark plug towards expanding the stable operating range of wet-ethanol-fueled engines. The stability range is investigated by examining the coefficient of variation of indicated mean effective pressure as a metric for instability, and indicated specific ethanol consumption as a metric for efficiency. The second goal is to examine the factors affecting the extent to which microwaves enhance ignition processes. The factors impacting microwave enhancement of ignition processes are individually examined, using flame development behavior as a key metric in determining microwave effectiveness. Further development of practical combustion applications implementing microwave

A phenomenographic study of students' experiences with transition from pre-college engineering programs to first-year engineering

NASA Astrophysics Data System (ADS)

Salzman, Noah

Recent national dialogues on the importance of preparing more students for careers in Science, Technology, Engineering, and Mathematics has driven the development of formal and informal learning opportunities for children and adolescents to explore engineering. Despite the growth of these programs, relatively little research exists on how participation in these programs affects students who choose to pursue further study in engineering. The present study addressed this gap through an exploration of the different ways that First-Year Engineering students experience the transition from pre-college engineering to undergraduate engineering studies. Given the focus of this research on students' experiences, phenomenography was chosen to explore the phenomenon of transition from pre-college to first-year engineering at a large, public Midwestern university. This facilitated understanding the range of variation in the ways that students experienced this transition. Twenty-two students with different amounts of participation in a variety of different engineering programs were selected to be interviewed using a purposeful maximum variation sampling strategy. The interviews were guided by a semi-structured interview protocol that encouraged the participants to reflect on their pre-college engineering experiences, their experiences in First-Year Engineering, and the transition between the two domains. The interviews were analyzed using phenomenographic methods to develop an outcome space consisting of five qualitatively different but related ways of experiencing the transition from pre-college to First-Year Engineering. These categories of description included Foreclosure, Frustration, Tedium, Connection, and Engaging Others. With the exception of the first category which was characterized by a lack of passion and commitment to engineering, the remaining four categories formed a hierarchical relationship representing increasing integration in First-Year Engineering. The

Simulation Study on Neoclassical Poloidal Viscosity in Helical Plasmas

NASA Astrophysics Data System (ADS)

Satake, Shinsuke

2012-10-01

In helical plasma confinement devices such as LHD, CHS and TU-Heliac, biasing experiments have been carried out to study the relationships among the ExB rotation, neoclassical poloidal viscosity (NPV), JxB torque of biasing current, and plasma confinement properties. In earlier studies using simple analytic formulae, it has been suggested that the transition phenomena of plasma transport found in the biasing experiments is attributed to nonlinear dependence of NPV on poloidal Mach number of the ExB rotation speed, or Mp. To study the NPV dependence on Mp in LHD biasing plasmas more in detail, we have applied FORTEC-3D drift-kinetic Monte-Carlo simulation code which can evaluate NPV precisely in realistic 3-D magnetic configurations. This is the first application of the massive neoclassical transport simulation to study the dependence of NPV on the magnetic configuration and rotation speed. In LHD plasmas, neoclassical transport properties such as radial particle transport and viscosity can be controlled by shifting the magnetic axis position. Our simulation study revealed that the NPV is drastically reduced if magnetic axis moves from 3.75m to 3.53m. As the biasing voltage, or Mp increases, it is found that the local maximum of NPV appears when |Mp|˜1, at which the transition of plasma transport properties is expected to happen. The transition Mp value is much smaller than that is predicted from simple analytic estimations. Comparing with the data from LHD biasing experiments, we confirmed that Mp near the electrode is about unity when a transition occurs, and also found that the peak NPV value at |Mp|˜1 agrees with the magnitude of JxB torque at the transition point. This suggests that our simulation successfully explains the nonlinear dependence of NPV and can give a quantitative evaluation of NPV in realistic LHD biasing experiment.

Artemis: Results of the engineering feasibility study

NASA Technical Reports Server (NTRS)

1991-01-01

Information is given in viewgraph form for the Engineering Feasibility Study of the Artemis Project, a plan to establish a permanent base on the Moon. Topics covered include the Common Lunar Lander (CLL), lunar lander engineering study results, lunar lander trajectory analysis, lunar lander conceptual design and mass properties, the lunar lander communication subsystem design, and product assurance.

Stratified charge rotary engine combustion studies

NASA Astrophysics Data System (ADS)

Shock, H.; Hamady, F.; Somerton, C.; Stuecken, T.; Chouinard, E.; Rachal, T.; Kosterman, J.; Lambeth, M.; Olbrich, C.

1989-07-01

Analytical and experimental studies of the combustion process in a stratified charge rotary engine (SCRE) continue to be the subject of active research in recent years. Specifically to meet the demand for more sophisticated products, a detailed understanding of the engine system of interest is warranted. With this in mind the objective of this work is to develop an understanding of the controlling factors that affect the SCRE combustion process so that an efficient power dense rotary engine can be designed. The influence of the induction-exhaust systems and the rotor geometry are believed to have a significant effect on combustion chamber flow characteristics. In this report, emphasis is centered on Laser Doppler Velocimetry (LDV) measurements and on qualitative flow visualizations in the combustion chamber of the motored rotary engine assembly. This will provide a basic understanding of the flow process in the RCE and serve as a data base for verification of numerical simulations. Understanding fuel injection provisions is also important to the successful operation of the stratified charge rotary engine. Toward this end, flow visualizations depicting the development of high speed, high pressure fuel jets are described. Friction is an important consideration in an engine from the standpoint of lost work, durability and reliability. MSU Engine Research Laboratory efforts in accessing the frictional losses associated with the rotary engine are described. This includes work which describes losses in bearing, seal and auxillary components. Finally, a computer controlled mapping system under development is described. This system can be used to map shapes such as combustion chamber, intake manifolds or turbine blades accurately.

Stratified charge rotary engine combustion studies

NASA Technical Reports Server (NTRS)

Shock, H.; Hamady, F.; Somerton, C.; Stuecken, T.; Chouinard, E.; Rachal, T.; Kosterman, J.; Lambeth, M.; Olbrich, C.

1989-01-01

Analytical and experimental studies of the combustion process in a stratified charge rotary engine (SCRE) continue to be the subject of active research in recent years. Specifically to meet the demand for more sophisticated products, a detailed understanding of the engine system of interest is warranted. With this in mind the objective of this work is to develop an understanding of the controlling factors that affect the SCRE combustion process so that an efficient power dense rotary engine can be designed. The influence of the induction-exhaust systems and the rotor geometry are believed to have a significant effect on combustion chamber flow characteristics. In this report, emphasis is centered on Laser Doppler Velocimetry (LDV) measurements and on qualitative flow visualizations in the combustion chamber of the motored rotary engine assembly. This will provide a basic understanding of the flow process in the RCE and serve as a data base for verification of numerical simulations. Understanding fuel injection provisions is also important to the successful operation of the stratified charge rotary engine. Toward this end, flow visualizations depicting the development of high speed, high pressure fuel jets are described. Friction is an important consideration in an engine from the standpoint of lost work, durability and reliability. MSU Engine Research Laboratory efforts in accessing the frictional losses associated with the rotary engine are described. This includes work which describes losses in bearing, seal and auxillary components. Finally, a computer controlled mapping system under development is described. This system can be used to map shapes such as combustion chamber, intake manifolds or turbine blades accurately.

Engineering study of the rotary-vee engine concept

NASA Technical Reports Server (NTRS)

Willis, Edward A.; Bartrand, Timothy A.; Beard, John E.

1989-01-01

The applicable thermodynamic cycle and performance considerations when the rotary-vee mechanism is used as an internal combustion (I.C.) heat engine are reviewed. Included is a simplified kinematic analysis and studies of the effects of design parameters on the critical pressures, torques and parasitic losses. A discussion of the principal findings is presented.

Orbit transfer vehicle engine study. Volume 2: Technical report

NASA Technical Reports Server (NTRS)

1980-01-01

The orbit transfer vehicle (OTV) engine study provided parametric performance, engine programmatic, and cost data on the complete propulsive spectrum that is available for a variety of high energy, space maneuvering missions. Candidate OTV engines from the near term RL 10 (and its derivatives) to advanced high performance expander and staged combustion cycle engines were examined. The RL 10/RL 10 derivative performance, cost and schedule data were updated and provisions defined which would be necessary to accommodate extended low thrust operation. Parametric performance, weight, envelope, and cost data were generated for advanced expander and staged combustion OTV engine concepts. A prepoint design study was conducted to optimize thrust chamber geometry and cooling, engine cycle variations, and controls for an advanced expander engine. Operation at low thrust was defined for the advanced expander engine and the feasibility and design impact of kitting was investigated. An analysis of crew safety and mission reliability was conducted for both the staged combustion and advanced expander OTV engine candidates.

Low voltage operation of plasma focus.

PubMed

Shukla, Rohit; Sharma, S K; Banerjee, P; Das, R; Deb, P; Prabahar, T; Das, B K; Adhikary, B; Shyam, A

2010-08-01

Plasma foci of compact sizes and operating with low energies (from tens of joules to few hundred joules) have found application in recent years and have attracted plasma-physics scientists and engineers for research in this direction. We are presenting a low energy and miniature plasma focus which operates from a capacitor bank of 8.4 muF capacity, charged at 4.2-4.3 kV and delivering approximately 52 kA peak current at approximately 60 nH calculated circuit inductance. The total circuit inductance includes the plasma focus inductance. The reported plasma focus operates at the lowest voltage among all reported plasma foci so far. Moreover the cost of capacitor bank used for plasma focus is nearly 20 U.S. dollars making it very cheap. At low voltage operation of plasma focus, the initial breakdown mechanism becomes important for operation of plasma focus. The quartz glass tube is used as insulator and breakdown initiation is done on its surface. The total energy of the plasma focus is approximately 75 J. The plasma focus system is made compact and the switching of capacitor bank energy is done by manual operating switch. The focus is operated with hydrogen and deuterium filled at 1-2 mbar.

The Madison plasma dynamo experiment: A facility for studying laboratory plasma astrophysics

NASA Astrophysics Data System (ADS)

Cooper, C. M.; Wallace, J.; Brookhart, M.; Clark, M.; Collins, C.; Ding, W. X.; Flanagan, K.; Khalzov, I.; Li, Y.; Milhone, J.; Nornberg, M.; Nonn, P.; Weisberg, D.; Whyte, D. G.; Zweibel, E.; Forest, C. B.

2014-01-01

The Madison plasma dynamo experiment (MPDX) is a novel, versatile, basic plasma research device designed to investigate flow driven magnetohydrodynamic instabilities and other high-β phenomena with astrophysically relevant parameters. A 3 m diameter vacuum vessel is lined with 36 rings of alternately oriented 4000 G samarium cobalt magnets, which create an axisymmetric multicusp that contains ˜14 m3 of nearly magnetic field free plasma that is well confined and highly ionized (>50%). At present, 8 lanthanum hexaboride (LaB6) cathodes and 10 molybdenum anodes are inserted into the vessel and biased up to 500 V, drawing 40 A each cathode, ionizing a low pressure Ar or He fill gas and heating it. Up to 100 kW of electron cyclotron heating power is planned for additional electron heating. The LaB6 cathodes are positioned in the magnetized edge to drive toroidal rotation through J × B torques that propagate into the unmagnetized core plasma. Dynamo studies on MPDX require a high magnetic Reynolds number Rm > 1000, and an adjustable fluid Reynolds number 10 < Re < 1000, in the regime where the kinetic energy of the flow exceeds the magnetic energy (MA2=(v/vA)2>1). Initial results from MPDX are presented along with a 0-dimensional power and particle balance model to predict the viscosity and resistivity to achieve dynamo action.

Advanced Vacuum Plasma Spray (VPS) for a Robust, Longlife and Safe Space Shuttle Main Engine (SSME)

NASA Technical Reports Server (NTRS)

Holmes, Richard R.; Elam, Sandra K.; McKechnie, Timothy N.; Power, Christopher A.

2010-01-01

In 1984, the Vacuum Plasma Spray Lab was built at NASA/Marshall Space Flight Center for applying durable, protective coatings to turbine blades for the space shuttle main engine (SSME) high pressure fuel turbopump. Existing turbine blades were cracking and breaking off after five hot fire tests while VPS coated turbine blades showed no wear or cracking after 40 hot fire tests. Following that, a major manufacturing problem of copper coatings peeling off the SSME Titanium Main Fuel Valve Housing was corrected with a tenacious VPS copper coating. A patented VPS process utilizing Functional Gradient Material (FGM) application was developed to build ceramic lined metallic cartridges for space furnace experiments, safely containing gallium arsenide at 1260 degrees centigrade. The VPS/FGM process was then translated to build robust, long life, liquid rocket combustion chambers for the space shuttle main engine. A 5K (5,000 Lb. thrust) thruster with the VPS/FGM protective coating experienced 220 hot firing tests in pristine condition with no wear compared to the SSME which showed blanching (surface pulverization) and cooling channel cracks in less than 30 of the same hot firing tests. After 35 of the hot firing tests, the injector face plates disintegrated. The VPS/FGM process was then applied to spraying protective thermal barrier coatings on the face plates which showed 50% cooler operating temperature, with no wear after 50 hot fire tests. Cooling channels were closed out in two weeks, compared to one year for the SSME. Working up the TRL (Technology Readiness Level) to establish the VPS/FGM process as viable technology, a 40K thruster was built and is currently being tested. Proposed is to build a J-2X size liquid rocket engine as the final step in establishing the VPS/FGM process TRL for space flight.

First Breakthrough for Future Air-Breathing Magneto-Plasma Propulsion Systems

NASA Astrophysics Data System (ADS)

Göksel, B.; Mashek, I. Ch

2017-04-01

A new breakthrough in jet propulsion technology since the invention of the jet engine is achieved. The first critical tests for future air-breathing magneto-plasma propulsion systems have been successfully completed. In this regard, it is also the first time that a pinching dense plasma focus discharge could be ignited at one atmosphere and driven in pulse mode using very fast, nanosecond electrostatic excitations to induce self-organized plasma channels for ignition of the propulsive main discharge. Depending on the capacitor voltage (200-600 V) the energy input at one atmosphere varies from 52-320 J/pulse corresponding to impulse bits from 1.2-8.0 mNs. Such a new pulsed plasma propulsion system driven with one thousand pulses per second would already have thrust-to-area ratios (50-150 kN/m²) of modern jet engines. An array of thrusters could enable future aircrafts and airships to start from ground and reach altitudes up to 50km and beyond. The needed high power could be provided by future compact plasma fusion reactors already in development by aerospace companies. The magneto-plasma compressor itself was originally developed by Russian scientists as plasma fusion device and was later miniaturized for supersonic flow control applications. So the first breakthrough is based on a spin-off plasma fusion technology.

A tandem mirror plasma source for hybrid plume plasma studies

NASA Technical Reports Server (NTRS)

Yang, T. F.; Chang, F. R.; Miller, R. H.; Wenzel, K. W.; Krueger, W. A.

1985-01-01

A tandem mirror device to be considered as a hot plasma source for the hybrid plume rocket concept is discussed. The hot plamsa from this device is injected into an exhaust duct, which will interact with an annular hypersonic layer of neutral gas. The device can be used to study the dynamics of the hybrid plume, and to verify the numerical predictions obtained with computer codes. The basic system design is also geared towards low weight and compactness, and high power density at the exhaust. The basic structure of the device consists of four major subsystems: (1) an electric power supply; (2) a low temperature, high density plasma gun, such as a stream gun, an MPD source or gas cell; (3) a power booster in the form of a tandem mirror machine; and (4) an exhaust nozzle arrangement. The configuration of the tandem mirror section is shown.

Plasma and Plasma Protein Product Transfusion: A Canadian Blood Services Centre for Innovation Symposium.

PubMed

Zeller, Michelle P; Al-Habsi, Khalid S; Golder, Mia; Walsh, Geraldine M; Sheffield, William P

2015-07-01

worlds of transfusable plasma, plasma protein products, and recombinant and engineered replacements. Copyright © 2015 Elsevier Inc. All rights reserved.

Back-diffusion plasma generator for ionosphere study

NASA Astrophysics Data System (ADS)

Fang, H. K.; Oyama, K.-I.; Chen, A. B.

2017-11-01

To produce ionospheric plasma environments at ground level is essential to get information not only for the development of CubeSat-class spacecraft but also for the design of ionospheric plasma instruments and to confirm their performance. In this paper, we describe the principle of plasma generation and characteristics of the back-diffusion plasma source, which can produce in-lab plasma similar to the Earth’s ionosphere, E and F regions, conditions of electron and ion temperature and density. The ion and electron energy distributions of the plasma generated by a back-diffusion source are measured by means of a cleaned Langmuir probe and gridded particle energy analyzers. The ion motion in front of the source is investigated by a hard-sphere collision model in SIMION software and the simulation results are comparable with the findings of our experiment. Furthermore, plasma densities and ion temperatures at different positions in front of the source are also demonstrated. The back-diffusion source has been accommodated for ionospheric plasma productions in several Asian institutes. The plasma characteristics of the source shown in this paper will benefit space research groups in the development of space plasma instruments.

Plasma Centrifuge Heat Engine - a Route to Non-thermal p- 11 B Fusion

NASA Astrophysics Data System (ADS)

Barnes, D. C.

2007-06-01

An invention [US Patent and Trademark Office App. Nos. 60/596567 (2005) and 60/766791 (2006)] combines centrifugal and dipole confinement, with recent oscillating plasma theory. The plasma undergoes compression/expansion (C/E), parallel to B by centrifugal force and perpendicular to B by B variation, providing a thermal cycle which recovers most (>95%) of heating as mechanical energy. This gives a "Q-amplifier" for beam-target systems. Centrifugally confined Boron plasma undergoes C/E by slow, cross-B interchange activity. Parallel and perpendicular C/E are matched by the rotation profile which arises naturally. Hot plasma is heated and cold plasma is cooled. Beam-target fusion reactions occur in the hot plasma region and expansion returns most of the heat energy as rotation energy. Rotation energy, in turn, produces waves which drive protons to an energy near the fusion peak cross section. A possible machine, including the arrangement of magnets and HV, is described.

Stability study: Transparent conducting oxides in chemically reactive plasmas

NASA Astrophysics Data System (ADS)

Manjunatha, Krishna Nama; Paul, Shashi

2017-12-01

Effect of plasma treatment on transparent conductive oxides (TCOs) including indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO) and aluminium-doped zinc oxide (AZO) are discussed. Stability of electrical and optical properties of TCOs, when exposed to plasma species generated from gases such as hydrogen and silane, are studied extensively. ITO and FTO thin films are unstable and reduce to their counterparts such as Indium and Tin when subjected to plasma. On the other hand, AZO is not only stable but also shows superior electrical and optical properties. The stability of AZO makes it suitable for electronic applications, such as solar cells and transistors that are fabricated under plasma environment. TCOs exposed to plasma with different fabrication parameters are used in the fabrication of silicon nanowire solar cells. The performance of solar cells, which is mired by the plasma, fabricated on ITO and FTO is discussed with respect to plasma exposure parameters while showing the advantages of using chemically stable AZO as an ideal TCO for solar cells. Additionally, in-situ diagnostic tool (optical emission spectroscopy) is used to monitor the deposition process and damage caused to TCOs.

Study of ion-irradiated tungsten in deuterium plasma

NASA Astrophysics Data System (ADS)

Khripunov, B. I.; Gureev, V. M.; Koidan, V. S.; Kornienko, S. N.; Latushkin, S. T.; Petrov, V. B.; Ryazanov, A. I.; Semenov, E. V.; Stolyarova, V. G.; Danelyan, L. S.; Kulikauskas, V. S.; Zatekin, V. V.; Unezhev, V. N.

2013-07-01

Experimental study aimed at investigation of neutron induced damage influence on fusion reactor plasma facing materials is reported. Displacement damage was produced in tungsten by high-energy helium and carbon ions at 3-10 MeV. The reached level of displacement damage ranged from several dpa to 600 dpa. The properties of the irradiated tungsten were studied in steady-state deuterium plasma on the LENTA linear divertor simulator. Plasma exposures were made at 250 eV of ion energy to fluence 1021-1022 ion/сm2. Erosion dynamics of the damaged layer and deuterium retention were observed. Surface microstructure modifications and important damage of the 5 μm layer shown. Deuterium retention in helium-damaged tungsten (ERD) showed its complex behavior (increase or decrease) depending on implanted helium quantity and the structure of the surface layer.

Engineering study on the rotary-vee engine concept

NASA Technical Reports Server (NTRS)

Willis, Edward A.; Bartland, Timothy A.; Beard, John E.

1989-01-01

This paper provides a review of the applicable thermodynamic cycle and performance considerations when the rotary-vee mechanism is used as an internal combustion (IC) heat engine. Included is a simplified kinematic analysis and studies of the effects of design parameters on the critical pressures, torques and parasitic losses. A discussion of the principal findings is presented.

Spectroscopic studies of microwave plasmas containing hexamethyldisiloxane

NASA Astrophysics Data System (ADS)

Nave, A. S. C.; Mitschker, F.; Awakowicz, P.; Röpcke, J.

2016-10-01

Low-pressure microwave discharges containing hexamethyldisiloxane (HMDSO) with admixtures of oxygen and nitrogen, used for the deposition of silicon containing films, have been studied spectroscopically. Optical emission spectroscopy (OES) in the visible spectral range has been combined with infrared laser absorption spectroscopy (IRLAS). The experiments were carried out in order to analyze the dependence of plasma chemical phenomena on power and gas mixture at relatively low pressures, up to 50 Pa, and power values, up to 2 kW. The evolution of the concentration of the methyl radical, CH3, and of seven stable molecules, HMDSO, CH4, C2H2, C2H4, C2H6, CO and CO2, was monitored in the plasma processes by in situ IRLAS using tunable lead salt diode lasers (TDL) and external-cavity quantum cascade lasers (EC-QCL) as radiation sources. To achieve reliable values for the gas temperature inside and outside the plasma bulk as well as for the temperature in the plasma hot and colder zones, which are of great importance for calculation of species concentrations, three different methods based on emission and absorption spectroscopy data of N2, CH3 and CO have been used. In this approach line profile analysis has been combined with spectral simulation methods. The concentrations of the various species, which were found to be in the range between 1011 to 1015 cm-3, are in the focus of interest. The influence of the discharge parameters power, pressure and gas mixture on the molecular concentrations has been studied. To achieve further insight into general plasma chemical aspects the dissociation of the HMDSO precursor gas including its fragmentation and conversion to the reaction products was analyzed in detail.

Engineering Students' Views of Corporate Social Responsibility: A Case Study from Petroleum Engineering.

PubMed

Smith, Jessica M; McClelland, Carrie J; Smith, Nicole M

2017-12-01

The mining and energy industries present unique challenges to engineers, who must navigate sometimes competing responsibilities and codes of conduct, such as personal senses of right and wrong, professional ethics codes, and their employers' corporate social responsibility (CSR) policies. Corporate social responsibility (CSR) is the current dominant framework used by industry to conceptualize firms' responsibilities to their stakeholders, yet has it plays a relatively minor role in engineering ethics education. In this article, we report on an interdisciplinary pedagogical intervention in a petroleum engineering seminar that sought to better prepare engineering undergraduate students to critically appraise the strengths and limitations of CSR as an approach to reconciling the interests of industry and communities. We find that as a result of the curricular interventions, engineering students were able to expand their knowledge of the social, rather than simply environmental and economic dimensions of CSR. They remained hesitant, however, in identifying the links between those social aspects of CSR and their actual engineering work. The study suggests that CSR may be a fruitful arena from which to illustrate the profoundly sociotechnical dimensions of the engineering challenges relevant to students' future careers.

PIC Simulations of Hypersonic Plasma Instabilities

NASA Astrophysics Data System (ADS)

Niehoff, D.; Ashour-Abdalla, M.; Niemann, C.; Decyk, V.; Schriver, D.; Clark, E.

2013-12-01

The plasma sheaths formed around hypersonic aircraft (Mach number, M > 10) are relatively unexplored and of interest today to both further the development of new technologies and solve long-standing engineering problems. Both laboratory experiments and analytical/numerical modeling are required to advance the understanding of these systems; it is advantageous to perform these tasks in tandem. There has already been some work done to study these plasmas by experiments that create a rapidly expanding plasma through ablation of a target with a laser. In combination with a preformed magnetic field, this configuration leads to a magnetic "bubble" formed behind the front as particles travel at about Mach 30 away from the target. Furthermore, the experiment was able to show the generation of fast electrons which could be due to instabilities on electron scales. To explore this, future experiments will have more accurate diagnostics capable of observing time- and length-scales below typical ion scales, but simulations are a useful tool to explore these plasma conditions theoretically. Particle in Cell (PIC) simulations are necessary when phenomena are expected to be observed at these scales, and also have the advantage of being fully kinetic with no fluid approximations. However, if the scales of the problem are not significantly below the ion scales, then the initialization of the PIC simulation must be very carefully engineered to avoid unnecessary computation and to select the minimum window where structures of interest can be studied. One method of doing this is to seed the simulation with either experiment or ion-scale simulation results. Previous experiments suggest that a useful configuration for studying hypersonic plasma configurations is a ring of particles rapidly expanding transverse to an external magnetic field, which has been simulated on the ion scale with an ion-hybrid code. This suggests that the PIC simulation should have an equivalent configuration

A review of studies on ion thruster beam and charge-exchange plasmas

NASA Technical Reports Server (NTRS)

Carruth, M. R., Jr.

1982-01-01

Various experimental and analytical studies of the primary beam and charge-exchange plasmas of ion thrusters are reviewed. The history of plasma beam research is recounted, emphasizing experiments on beam neutralization, expansion of the beam, and determination of beam parameters such as electron temperature, plasma density, and plasma potential. The development of modern electron bombardment ion thrusters is treated, detailing experimental results. Studies on charge-exchange plasma are discussed, showing results such as the relationship between neutralizer emission current and plasma beam potential, ion energies as a function of neutralizer bias, charge-exchange ion current collected by an axially moving Faraday cup-RPA for 8-cm and 30-cm ion thrusters, beam density and potential data from a 15-cm ion thruster, and charge-exchange ion flow around a 30-cm thruster. A 20-cm thruster electrical configuration is depicted and facility effects are discussed. Finally, plasma modeling is covered in detail for plasma beam and charge-exchange plasma.

Advanced rotary engine studies

NASA Technical Reports Server (NTRS)

Jones, C.

1980-01-01

A review of rotary engine developments relevant to a stratified charge rotary aircraft engine is presented. Advantages in module size and weight, fuel efficiency, reliability, and multi-fuel capability are discussed along with developments in turbocharging, increased mean effective pressure, improved apex seal/trochoid wear surfacing materials, and high strength and temperature aluminum casting alloys. A carbureted prototype aircraft engine is also described.

Study of advanced rotary combustion engines for commuter aircraft

NASA Technical Reports Server (NTRS)

Berkowitz, M.; Jones, C.; Myers, D.

1983-01-01

Performance, weight, size, and maintenance data for advanced rotary aircraft engines suitable for comparative commuter aircraft system evaluation studies of alternate engine candidates are provided. These are turbocharged, turbocompounded, direct injected, stratified charge rotary engines. Hypothetical engines were defined (an RC4-74 at 895 kW and an RC6-87 at 1490 kW) based on the technologies and design approaches used in the highly advanced engine of a study of advanced general aviation rotary engines. The data covers the size range of shaft power from 597 kW (800 hp) to 1865 kW (2500 hp) and is in the form of drawings, tables, curves and written text. These include data on internal geometry and configuration, installation information, turbocharging and turbocompounding arrangements, design features and technologies, engine cooling, fuels, scaling for weight size BSFC and heat rejection for varying horsepower, engine operating and performance data, and TBO and maintenance requirements. The basic combustion system was developed and demonstrated; however the projected power densities and performance efficiencies require increases in engine internal pressures, thermal loading, and rotative speed.

Continuing Engineering Studies Series; Monograph No. 3.

ERIC Educational Resources Information Center

American Society for Engineering Education, Washington, DC.

Interest in continuing engineering studies has been growing within the American Society for Engineering Education as well as among educational institutions, industrial organizations, professional association, and governmental agencies. Feeling a national need for uniformity, in 1968 the National Planning Conference authorized a National Task Force…

Plasma jet ignition device

DOEpatents

McIlwain, Michael E.; Grant, Jonathan F.; Golenko, Zsolt; Wittstein, Alan D.

1985-01-15

An ignition device of the plasma jet type is disclosed. The device has a cylindrical cavity formed in insulating material with an electrode at one end. The other end of the cylindrical cavity is closed by a metal plate with a small orifice in the center which plate serves as a second electrode. An arc jumping between the first electrode and the orifice plate causes the formation of a highly-ionized plasma in the cavity which is ejected through the orifice into the engine cylinder area to ignite the main fuel mixture. Two improvements are disclosed to enhance the operation of the device and the length of the plasma plume. One improvement is a metal hydride ring which is inserted in the cavity next to the first electrode. During operation, the high temperature in the cavity and the highly excited nature of the plasma breaks down the metal hydride, liberating hydrogen which acts as an additional fuel to help plasma formation. A second improvement consists of a cavity insert containing a plurality of spaced, metal rings. The rings act as secondary spark gap electrodes reducing the voltage needed to maintain the initial arc in the cavity.

UHB Engine Fan Broadband Noise Reduction Study

NASA Technical Reports Server (NTRS)

Gliebe, Philip R.; Ho, Patrick Y.; Mani, Ramani

1995-01-01

A study has been completed to quantify the contribution of fan broadband noise to advanced high bypass turbofan engine system noise levels. The result suggests that reducing fan broadband noise can produce 3 to 4 EPNdB in engine system noise reduction, once the fan tones are eliminated. Further, in conjunction with the elimination of fan tones and an increase in bypass ratio, a potential reduction of 7 to 10 EPNdB in system noise can be achieved. In addition, an initial assessment of engine broadband noise source mechanisms has been made, concluding that the dominant source of fan broadband noise is the interaction of incident inlet boundary layer turbulence with the fan rotor. This source has two contributors, i.e., unsteady life dipole response and steady loading quadrupole response. The quadrupole contribution was found to be the most important component, suggesting that broadband noise reduction can be achieved by the reduction of steady loading field-turbulence field quadrupole interaction. Finally, for a controlled experimental quantification and verification, the study recommends that further broadband noise tests be done on a simulated engine rig, such as the GE Aircraft Engine Universal Propulsion Simulator, rather than testing on an engine statically in an outdoor arena The rig should be capable of generating forward and aft propagating fan noise, and it needs to be tested in a large freejet or a wind tunnel.

UHB engine fan broadband noise reduction study

NASA Astrophysics Data System (ADS)

Gliebe, Philip R.; Ho, Patrick Y.; Mani, Ramani

1995-06-01

A study has been completed to quantify the contribution of fan broadband noise to advanced high bypass turbofan engine system noise levels. The result suggests that reducing fan broadband noise can produce 3 to 4 EPNdB in engine system noise reduction, once the fan tones are eliminated. Further, in conjunction with the elimination of fan tones and an increase in bypass ratio, a potential reduction of 7 to 10 EPNdB in system noise can be achieved. In addition, an initial assessment of engine broadband noise source mechanisms has been made, concluding that the dominant source of fan broadband noise is the interaction of incident inlet boundary layer turbulence with the fan rotor. This source has two contributors, i.e., unsteady life dipole response and steady loading quadrupole response. The quadrupole contribution was found to be the most important component, suggesting that broadband noise reduction can be achieved by the reduction of steady loading field-turbulence field quadrupole interaction. Finally, for a controlled experimental quantification and verification, the study recommends that further broadband noise tests be done on a simulated engine rig, such as the GE Aircraft Engine Universal Propulsion Simulator, rather than testing on an engine statically in an outdoor arena The rig should be capable of generating forward and aft propagating fan noise, and it needs to be tested in a large freejet or a wind tunnel.

Feasibility study for convertible engine torque converter

NASA Technical Reports Server (NTRS)

1985-01-01

The feasibility study has shown that a dump/fill type torque converter has excellent potential for the convertible fan/shaft engine. The torque converter space requirement permits internal housing within the normal flow path of a turbofan engine at acceptable engine weight. The unit permits operating the engine in the turboshaft mode by decoupling the fan. To convert to turbofan mode, the torque converter overdrive capability bring the fan speed up to the power turbine speed to permit engagement of a mechanical lockup device when the shaft speed are synchronized. The conversion to turbofan mode can be made without drop of power turbine speed in less than 10 sec. Total thrust delivered to the aircraft by the proprotor, fan, and engine during tansient can be controlled to prevent loss of air speed or altitude. Heat rejection to the oil is low, and additional oil cooling capacity is not required. The turbofan engine aerodynamic design is basically uncompromised by convertibility and allows proper fan design for quiet and efficient cruise operation. Although the results of the feasibility study are exceedingly encouraging, it must be noted that they are based on extrapolation of limited existing data on torque converters. A component test program with three trial torque converter designs and concurrent computer modeling for fluid flow, stress, and dynamics, updated with test results from each unit, is recommended.

Studying astrophysical particle acceleration with laser-driven plasmas

NASA Astrophysics Data System (ADS)

Fiuza, Frederico

2016-10-01

The acceleration of non-thermal particles in plasmas is critical for our understanding of explosive astrophysical phenomena, from solar flares to gamma ray bursts. Particle acceleration is thought to be mediated by collisionless shocks and magnetic reconnection. The microphysics underlying these processes and their ability to efficiently convert flow and magnetic energy into non-thermal particles, however, is not yet fully understood. By performing for the first time ab initio 3D particle-in-cell simulations of the interaction of both magnetized and unmagnetized laser-driven plasmas, it is now possible to identify the optimal parameters for the study of particle acceleration in the laboratory relevant to astrophysical scenarios. It is predicted for the Omega and NIF laser conditions that significant non-thermal acceleration can occur during magnetic reconnection of laser-driven magnetized plasmas. Electrons are accelerated by the electric field near the X-points and trapped in contracting magnetic islands. This leads to a power-law tail extending to nearly a hundred times the thermal energy of the plasma and that contains a large fraction of the magnetic energy. The study of unmagnetized interpenetrating plasmas also reveals the possibility of forming collisionless shocks mediated by the Weibel instability on NIF. Under such conditions, both electrons and ions can be energized by scattering out of the Weibel-mediated turbulence. This also leads to power-law spectra that can be detected experimentally. The resulting experimental requirements to probe the microphysics of plasma particle acceleration will be discussed, paving the way for the first experiments of these important processes in the laboratory. As a result of these simulations and theoretical analysis, there are new experiments being planned on the Omega, NIF, and LCLS laser facilities to test these theoretical predictions. This work was supported by the SLAC LDRD program and DOE Office of Science, Fusion

Energy efficient engine preliminary design and integration study

NASA Technical Reports Server (NTRS)

Gray, D. E.

1978-01-01

The technology and configurational requirements of an all new 1990's energy efficient turbofan engine having a twin spool arrangement with a directly coupled fan and low-pressure turbine, a mixed exhaust nacelle, and a high 38.6:1 overall pressure ratio were studied. Major advanced technology design features required to provide the overall benefits were a high pressure ratio compression system, a thermally actuated advanced clearance control system, lightweight shroudless fan blades, a low maintenance cost one-stage high pressure turbine, a short efficient mixer and structurally integrated engine and nacelle. A conceptual design analysis was followed by integration and performance analyses of geared and direct-drive fan engines with separate or mixed exhaust nacelles to refine previously designed engine cycles. Preliminary design and more detailed engine-aircraft integration analysis were then conducted on the more promising configurations. Engine and aircraft sizing, fuel burned, and airframe noise studies on projected 1990's domestic and international aircraft produced sufficient definition of configurational and advanced technology requirements to allow immediate initiation of component technology development.

Application of Plasma Technology in the Life Sciences

NASA Astrophysics Data System (ADS)

Short, Robert

2002-10-01

This paper explores the versatility of plasma polymerization in the fabrication of surfaces for use in the Life Sciences and Tissue Engineering, highlighting three successful applications of plasma polymerized surfaces. 1. Plasma polymerized acrylic acid surfaces have been used as substrates for the culture and delivery of keratinocytes (skin cells) to chronic wounds. In proof of concept studies weekly delivery of keratinocytes have promoted healing in previously non-healing wounds. These include diabetic foot ulcers and wounds where skin grafts would normally be considered, but were contra-indicated. 2. Surface chemical patterning on the micrometer scale- length, by use of pre-fabricated masks, has been used to control the spatial binding of proteins and cells. This technology makes possible a significant reduction in size of biological assays, reducing the amount of material (e.g. antibody) or cells required. 3. Surface chemical potential gradients, from a few tens of micrometers to a few centrimeters, have been fabricated by "plasma writing", a technique currently being developed in Sheffield. These gradients are being developed to separate mixtures of biomolecules or cells.

Small Engine Technology (SET) - Task 4, Regional Turboprop/Turbofan Engine Advanced Combustor Study

NASA Technical Reports Server (NTRS)

Reynolds, Robert; Srinivasan, Ram; Myers, Geoffrey; Cardenas, Manuel; Penko, Paul F. (Technical Monitor)

2003-01-01

Under the SET Program Task 4 - Regional Turboprop/Turbofan Engine Advanced Combustor Study, a total of ten low-emissions combustion system concepts were evaluated analytically for three different gas turbine engine geometries and three different levels of oxides of nitrogen (NOx) reduction technology, using an existing AlliedSignal three-dimensional (3-D) Computational Fluid Dynamics (CFD) code to predict Landing and Takeoff (LTO) engine cycle emission values. A list of potential Barrier Technologies to the successful implementation of these low-NOx combustor designs was created and assessed. A trade study was performed that ranked each of the ten study configurations on the basis of a number of manufacturing and durability factors, in addition to emissions levels. The results of the trade study identified three basic NOx-emissions reduction concepts that could be incorporated in proposed follow-on combustor technology development programs aimed at demonstrating low-NOx combustor hardware. These concepts are: high-flow swirlers and primary orifices, fuel-preparation cans, and double-dome swirlers.

High temperature solar photon engines. [heat engines for terrestrial and space-based solar power plants

NASA Technical Reports Server (NTRS)

Hertzberg, A.; Decher, R.; Mattick, A. T.; Lau, C. V.

1978-01-01

High temperature heat engines designed to make maximum use of the thermodynamic potential of concentrated solar radiation are described. Plasmas between 2000 K and 4000 K can be achieved by volumetric absorption of radiation in alkali metal vapors, leading to thermal efficiencies up to 75% for terrestrial solar power plants and up to 50% for space power plants. Two machines capable of expanding hot plasmas using practical technology are discussed. A binary Rankine cycle uses fluid mechanical energy transfer in a device known as the 'Comprex' or 'energy exchanger.' The second machine utilizes magnetohydrodynamics in a Brayton cycle for space applications. Absorption of solar energy and plasma radiation losses are investigated for a solar superheater using potassium vapor.

Buffalo plasma fibronectin: a physico-chemical study.

PubMed

Ahmed, N; Chandra, R; Raj, H G

2001-12-01

Plasma fibronectin (FN) of buffalo (Babulis babulis) was purified to apparent homogeneity, using gelatin-Sepharose and heparin-Sepharose affinity columns. It was found to have two subunits of molecular mass 246 kDa and 228 kDa, on SDS-gel. Its immunological cross-reactivity with anti-human plasma FN was confirmed by Western blotting. The amino acid composition was found to be similar to that of human and bovine plasma FNs. Buffalo plasma FN contained 2.23% neutral hexoses and 1.18% sialic acids. No titrable sulfhydryl group could be detected in the absence of denaturant. Reaction with DTNB indicated 3.4 sulfhydryl groups in the molecule, whereas BDC-OH titration gave a value of 3.8 -SH groups in buffalo plasma FN. Stoke's radius, intrinsic viscosity, diffusion coefficient and frictional ratio indicated that buffalo plasma FN did not have a compact globular conformation at physiological pH and ionic strength. Molecular dimensions (average length, 120 nm; molar mass to length ratio, 3950 nm(-1) and mean diameter, 2.4 nm) as revealed by rotary shadowing electron microscopy further supported the extended conformation of buffalo plasma FN. These results show that buffalo plasma FN has similar properties as that of human plasma FN.

Proceedings of the 1998 diesel engine emissions reduction workshop [DEER

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This workshop was held July 6--9, 1998 in Castine, Maine. The purpose of this workshop was to provide a multidisciplinary forum for exchange of state-of-the-art information on reduction of diesel engine emissions. Attention was focused on the following: agency/organization concerns on engine emissions; diesel engine issues and challenges; health risks from diesel engines emissions; fuels and lubrication technologies; non-thermal plasma and urea after-treatment technologies; and diesel engine technologies for emission reduction 1 and 2.

Numerical Study of Suspension Plasma Spraying

NASA Astrophysics Data System (ADS)

Farrokhpanah, Amirsaman; Coyle, Thomas W.; Mostaghimi, Javad

2017-01-01

A numerical study of suspension plasma spraying is presented in the current work. The liquid suspension jet is replaced with a train of droplets containing the suspension particles injected into the plasma flow. Atomization, evaporation, and melting of different components are considered for droplets and particles as they travel toward the substrate. Effect of different parameters on particle conditions during flight and upon impact on the substrate is investigated. Initially, influence of the torch operating conditions such as inlet flow rate and power is studied. Additionally, effect of injector parameters like injection location, flow rate, and angle is examined. The model used in the current study takes high-temperature gradients and non-continuum effects into account. Moreover, the important effect of change in physical properties of suspension droplets as a result of evaporation is included in the model. These mainly include variations in heat transfer properties and viscosity. Utilizing this improved model, several test cases have been considered to better evaluate the effect of different parameters on the quality of particles during flight and upon impact on the substrate.

Study of Plasma Flow Modes in Imploding Nested Arrays

NASA Astrophysics Data System (ADS)

Mitrofanov, K. N.; Aleksandrov, V. V.; Gritsuk, A. N.; Branitsky, A. V.; Frolov, I. N.; Grabovski, E. V.; Sasorov, P. V.; Ol'khovskaya, O. G.; Zaitsev, V. I.

2018-02-01

Results from experimental studies of implosion of nested wire and fiber arrays at currents of up to 4 MA at the Angara-5-1 facility are presented. Depending on the ratio between the radii of the inner and outer arrays, different modes of the plasma flow in the space between the inner and outer arrays were implemented: the sub-Alfvénic ( V r < V A ) and super-Alfvénic ( V r > V A ) modes and a mode with the formation of the transition shock wave (SW) region between the cascades. By varying the material of the outer array (tungsten wires or kapron fibers), it is shown that the plasma flow mode between the inner and outer arrays depends on the ratio between the plasma production rates ṁ in / ṁ out in the inner and outer arrays. The obtained experimental results are compared with the results of one-dimensional MHD simulation of the plasma flow between the arrays. Stable implosion of the inner array plasma was observed in experiments with combined nested arrays consisting of a fiber outer array and a tungsten inner array. The growth rates of magnetic Rayleigh-Taylor (MRT) instability in the inner array plasma at different numbers of fibers in the outer array and different ratios between the radii of the inner and outer arrays are compared. Suppression of MRT instability during the implosion of the inner array plasma results in the formation of a stable compact Z-pinch and generation of a soft X-ray pulse. A possible scenario of interaction between the plasmas of the inner and outer arrays is offered. The stability of the inner array plasma in the stage of final compression depends on the character of interaction of plasma jets from the outer array with the magnetic field of the inner array.

Orbit transfer vehicle engine study, phase A extension. Volume 2A: Study results

NASA Technical Reports Server (NTRS)

1980-01-01

Engine trade studies and systems analyses leading to a baseline engine selection for advanced expander cycle engine are discussed with emphasis on: (1) performance optimization of advanced expander cycle engines in the 10 to 20K pound thrust range; (2) selection of a recommended advanced expander engine configuration based on maximized performance and minimized mission risk, and definition of the components for this configuration; (3) characterization of the low thrust adaptation requirements and performance for the staged combustion engine; (4) generation of a suggested safety and reliability approach for OTV engines independent of engine cycle; (5) definition of program risk relationships between expander and staged combustion cycle engines; and (6) development of schedules and costs for the DDT&E, production, and operation phases of the 10K pound thrust expander engine program.

A Case Study of Engineering Ethics

NASA Astrophysics Data System (ADS)

Shimizu, Kazuo

In Engineering Ethics Class at Shizuoka University, the Code of Ethics and Cases for Electrical Engineers by IEEJ Ethics committee is used to promote for high education effect to correspond large number of students (140students). In this paper, a case study in the class, and survey results for ethics value of students are presented. In addition, some comments for role playing act on the case of virtual experiences by students are described.

Solar-Powered Electric Propulsion Systems: Engineering and Applications

NASA Technical Reports Server (NTRS)

Stearns, J. W.; Kerrisk, D. J.

1966-01-01

Lightweight, multikilowatt solar power arrays in conjunction with electric propulsion offer potential improvements to space exploration, extending the usefulness of existing launch vehicles to higher-energy missions. Characteristics of solar-powered electric propulsion missions are outlined, and preliminary performance estimates are shown. Spacecraft system engineering is discussed with respect to parametric trade-offs in power and propulsion system design. Relationships between mission performance and propulsion system performance are illustrated. The present state of the art of electric propulsion systems is reviewed and related to the mission requirements identified earlier. The propulsion system design and test requirements for a mission spacecraft are identified and discussed. Although only ion engine systems are currently available, certain plasma propulsion systems offer some advantages in over-all system design. These are identified, and goals are set for plasma-thrustor systems to make them competitive with ion-engine systems for mission applications.

Transport Studies in Alcator C-Mod ITB Plasmas

NASA Astrophysics Data System (ADS)

Fiore, C. L.; Bonoli, P. T.; Ernst, D.; Greenwald, M. J.; Ince-Cushman, A.; Lin, L.; Marmar, E. S.; Porkolab, M.; Rice, J. E.; Wukitch, S.; Rowan, W.; Bespamyatnov, I.; Phillips, P.

2008-11-01

Internal transport barriers occur in C-Mod plasmas that have off-axis ICRF heating and also in Ohmic H-mode plasmas. These ITBs are marked by highly peaked density and pressure profiles, as they rely on a reduction of particle and thermal flux in the barrier region which allows the neoclassical pinch to peak the central density without reducing the central temperature. Enhancement of several core diagnostics has resulted in increased understanding of C-Mod ITBs. Ion temperature profile measurements have been obtained using an innovative design for x-ray crystal spectrometry and clearly show a barrier forming in the ion temperature profile. The phase contrast imaging (PCI) provides limited localization of the ITB related fluctuations that increase in strength as the central density increases. Simulation of triggering conditions, integrated simulations with fluctuation measurements, parametric studies, and transport implications of fully ionized boron impurity profiles in the plasma are under study. A summary of these results will be presented.

S-Duct Engine Inlet Flow Control Using SDBD Plasma Streamwise Vortex Generators

NASA Astrophysics Data System (ADS)

Kelley, Christopher; He, Chuan; Corke, Thomas

2009-11-01

The results of a numerical simulation and experiment characterizing the performance of plasma streamwise vortex generators in controlling separation and secondary flow within a serpentine, diffusing duct are presented. A no flow control case is first run to check agreement of location of separation, development of secondary flow, and total pressure recovery between the experiment and numerical results. Upon validation, passive vane-type vortex generators and plasma streamwise vortex generators are implemented to increase total pressure recovery and reduce flow distortion at the aerodynamic interface plane: the exit of the S-duct. Total pressure recovery is found experimentally with a pitot probe rake assembly at the aerodynamic interface plane. Stagnation pressure distortion descriptors are also presented to show the performance increase with plasma streamwise vortex generators in comparison to the baseline no flow control case. These performance parameters show that streamwise plasma vortex generators are an effective alternative to vane-type vortex generators in total pressure recovery and total pressure distortion reduction in S-duct inlets.

Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

NASA Astrophysics Data System (ADS)

Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

2006-09-01

An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22cm diameter and 30cm length, purifies an airflow rate of 5000lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application.

Evaluation of mechanism of cold atmospheric pressure plasma assisted polymerization of acrylic acid on low density polyethylene (LDPE) film surfaces: Influence of various gaseous plasma pretreatment

NASA Astrophysics Data System (ADS)

Ramkumar, M. C.; Pandiyaraj, K. Navaneetha; Arun Kumar, A.; Padmanabhan, P. V. A.; Uday Kumar, S.; Gopinath, P.; Bendavid, A.; Cools, P.; De Geyter, N.; Morent, R.; Deshmukh, R. R.

2018-05-01

Owing to its exceptional physiochemical properties, low density poly ethylene (LDPE) has wide range of tissue engineering applications. Conversely, its inadequate surface properties make LDPE an ineffectual candidate for cell compatible applications. Consequently, plasma-assisted polymerization with a selected precursor is a good choice for enhancing its biocompatibility. The present investigation studies the efficiency of plasma polymerization of acrylic acid (AAC) on various gaseous plasma pretreated LDPE films by cold atmospheric pressure plasma, to enhance its cytocompatibility. The change in chemical composition and surface topography of various gaseous plasma pretreated and acrylic deposited LDPE films has been assessed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The changes in hydrophilic nature of surface modified LDPE films were studied by contact angle (CA) analysis. Cytocompatibility of the AAC/LDPE films was also studied in vitro, using RIN-5F cells. The results acquired by the XPS and AFM analysis clearly proved that cold atmospheric pressure (CAP) plasma assisted polymerization of AAC enhances various surface properties including carboxylic acid functional group density and increased surface roughness on various gaseous plasma treated AAC/LDPE film surfaces. Moreover, contact angle analysis clearly showed that the plasma polymerized samples were hydrophilic in nature. In vitro cytocompatibility analysis undoubtedly validates that the AAC polymerized various plasma pretreated LDPE films surfaces stimulate cell distribution and proliferation compared to pristine LDPE films. Similarly, cytotoxicity analysis indicates that the AAC deposited various gaseous plasma pretreated LDPE film can be considered as non-toxic as well as stimulating cell viability significantly. The cytocompatible properties of AAC polymerized Ar + O2 plasma pretreated LDPE films were found to be more pronounced compared to the other plasma pretreated

A Huygens immersed-finite-element particle-in-cell method for modeling plasma-surface interactions with moving interface

NASA Astrophysics Data System (ADS)

Cao, Huijun; Cao, Yong; Chu, Yuchuan; He, Xiaoming; Lin, Tao

2018-06-01

Surface evolution is an unavoidable issue in engineering plasma applications. In this article an iterative method for modeling plasma-surface interactions with moving interface is proposed and validated. In this method, the plasma dynamics is simulated by an immersed finite element particle-in-cell (IFE-PIC) method, and the surface evolution is modeled by the Huygens wavelet method which is coupled with the iteration of the IFE-PIC method. Numerical experiments, including prototypical engineering applications, such as the erosion of Hall thruster channel wall, are presented to demonstrate features of this Huygens IFE-PIC method for simulating the dynamic plasma-surface interactions.

Shuttle wave experiments. [space plasma investigations: design and instrumentation

NASA Technical Reports Server (NTRS)

Calvert, W.

1976-01-01

Wave experiments on shuttle are needed to verify dispersion relations, to study nonlinear and exotic phenomena, to support other plasma experiments, and to test engineering designs. Techniques based on coherent detection and bistatic geometry are described. New instrumentation required to provide modules for a variety of missions and to incorporate advanced signal processing and control techniques is discussed. An experiment for Z to 0 coupling is included.

Laser-pulse compression using magnetized plasmas

DOE PAGES

Shi, Yuan; Qin, Hong; Fisch, Nathaniel J.

2017-02-28

Proposals to reach the next generation of laser intensities through Raman or Brillouin backscattering have centered on optical frequencies. Higher frequencies are beyond the range of such methods mainly due to the wave damping that accompanies the higher-density plasmas necessary for compressing higher frequency lasers. However, we find that an external magnetic field transverse to the direction of laser propagation can reduce the required plasma density. Using parametric interactions in magnetized plasmas to mediate pulse compression, both reduces the wave damping and alleviates instabilities, thereby enabling higher frequency or lower intensity pumps to produce pulses at higher intensities and longermore » durations. Finally, in addition to these theoretical advantages, our method in which strong uniform magnetic fields lessen the need for high-density uniform plasmas also lessens key engineering challenges or at least exchanges them for different challenges.« less

Foundations of low-temperature plasma physics—an introduction

NASA Astrophysics Data System (ADS)

von Keudell, A.; Schulz-von der Gathen, V.

2017-11-01

The use of plasmas as a reactive mixture of ions, electrons and neutrals is at the core of numerous technologies in industry, enabling applications in microelectronics, automotives, packaging, environment and medicine. Recently, even the use of plasmas in medical applications has made great progress. The dominant character of a plasma is often its non equilibrium nature with different temperatures for the individual species in a plasma, the ions, electrons and neutrals. This opens up a multitude of reaction pathways which are inaccessible to conventional methods in chemistry, for example. The understanding of plasmas requires expertise in plasma physics, plasma chemistry and in electrical engineering. This first paper in a series of foundation papers on low temperature plasma science is intended to provide the very basics of plasmas as a common starting point for the more in-depth discussion of particular plasma generation methods, plasma modeling and diagnostics in the other foundation papers. In this first paper of the series, the common terminology, definitions and main concepts are introduced. The covered aspects start with the basic definitions and include further plasma equilibria, particle collisions and transport, sheaths and discharge breakdowns.

Modified RS2101 rocket engine study program

NASA Technical Reports Server (NTRS)

1971-01-01

The purpose of the program is to perform design studies and analyses to determine the effects of incorporating a 60:1 expansion area ratio nozzle extension, extended firing time, and modified operating conditions and environments on the MM'71 rocket engine assembly. An injector-to-thrust chamber seal study was conducted to define potential solutions for leakage past this joint. The results and recommendations evolving from the engine thermal analyses, the injector-to-thrust chamber seal studies, and the nozzle extension joint stress analyses are presented.

Chemical reaction and dust formation studies in laboratory hydrocarbon plasmas.

NASA Astrophysics Data System (ADS)

Hippler, Rainer; Majumdar, Abhijit; Thejaswini, H. C.

Plasma chemical reaction studies with relevance to, e.g., Titan's atmosphere have been per-formed in various laboratory plasmas [1,2]. Chemical reactions in a dielectric barrier discharge at medium pressure of 250-300 mbar have been studied in CH4 /N2 and CH4 /Ar gas mixtures by means of mass spectrometry. The main reaction scheme is production of H2 by fragmenta-tion of CH4 , but also production of larger hydrocarbons like Cn Hm with n up to 10 including formation of different functional CN groups is observed. [1] A. Majumdar and R. Hippler, Development of dielectric barrier discharge plasma processing apparatus for mass spectrometry and thin film deposition, Rev. Sci. Instrum. 78, 075103 (2007) [2] H.T. Do, G. Thieme, M. Frühlich, H. Kersten, and R. Hippler, Ion Molecule and Dust Particle Formation in Ar/CH4 , Ar/C2 H2 and Ar/C3 H6 Radio-frequency Plasmas, Contrib. Plasma Phys. 45, No. 5-6, 378-384 (2005)

Space transportation booster engine configuration study. Volume 1: Executive Summary

NASA Technical Reports Server (NTRS)

1989-01-01

The objective of the Space Transportation Booster Engine (STBE) Configuration Study is to contribute to the Advanced Launch System (ALS) development effort by providing highly reliable, low cost booster engine concepts for both expendable and reusable rocket engines. The objectives of the Space Transportation Booster Engine (STBE) Configuration Study were to identify engine configurations which enhance vehicle performance and provide operational flexibility at low cost, and to explore innovative approaches to the follow-on full-scale development (FSD) phase for the STBE.

Overview of thermal barrier coatings in diesel engines

NASA Technical Reports Server (NTRS)

Yonushonis, T. M.

1995-01-01

An understanding of delamination mechanisms in thermal barrier coatings has been developed for diesel applications through nondestructive evaluation, structural analysis modeling and engine evaluation of various thermal barrier coatings. This knowledge has resulted in improved thermal barrier coatings which survive abusive cyclic fatigue tests in high output diesel engines. Significant efforts are still required to improve the plasma spray processing capability and the economics for complex geometry diesel engine components. Data obtained from advanced diesel engines on the effect of thermal barrier coatings on engine fuel economy and emission has not been encouraging. Although the underlying metal component temperatures have been reduced through the use of thermal barrier coating, engine efficiency and emission trends have not been promising.

Measurements of Ion and Neutral Fluctuation Changes with Pressure in a Large-Scale Helicon Plasma

NASA Astrophysics Data System (ADS)

Dwyer, R. H.; Fisher, D. M.; Kelly, R. F.; Hatch, M. W.; Gilmore, M.

2017-10-01

Neutral particle dynamics may play an important role both in laboratory plasmas and in the edge of magnetic fusion devices. However, studies of neutral dynamics in these plasmas have been limited to date. Here we report on a basic study of ion and neutral fluctuations as a function of background neutral gas pressure. These experiments have been conducted in helicon discharges in the HelCat (Helicon-Cathode) dual-source plasma device at the University of New Mexico. The goal is to measure changes in ion and neutral density fluctuations with pressure and to gain an improved understanding of plasma-neutral interactions. Langmuir probe, Ar-I LIF, and high-speed imaging measurements of the fluctuations will be presented. Supported by U.S. National Science Foundation Award 1500423 and The University of New Mexico School of Engineering.

The Madison plasma dynamo experiment: A facility for studying laboratory plasma astrophysics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, C. M.; Brookhart, M.; Collins, C.

2014-01-15

The Madison plasma dynamo experiment (MPDX) is a novel, versatile, basic plasma research device designed to investigate flow driven magnetohydrodynamic instabilities and other high-β phenomena with astrophysically relevant parameters. A 3 m diameter vacuum vessel is lined with 36 rings of alternately oriented 4000 G samarium cobalt magnets, which create an axisymmetric multicusp that contains ∼14 m{sup 3} of nearly magnetic field free plasma that is well confined and highly ionized (>50%). At present, 8 lanthanum hexaboride (LaB{sub 6}) cathodes and 10 molybdenum anodes are inserted into the vessel and biased up to 500 V, drawing 40 A each cathode, ionizing a low pressuremore » Ar or He fill gas and heating it. Up to 100 kW of electron cyclotron heating power is planned for additional electron heating. The LaB{sub 6} cathodes are positioned in the magnetized edge to drive toroidal rotation through J × B torques that propagate into the unmagnetized core plasma. Dynamo studies on MPDX require a high magnetic Reynolds number Rm > 1000, and an adjustable fluid Reynolds number 10 < Re < 1000, in the regime where the kinetic energy of the flow exceeds the magnetic energy (M{sub A}{sup 2}=(v/v{sub A}){sup 2}>1). Initial results from MPDX are presented along with a 0-dimensional power and particle balance model to predict the viscosity and resistivity to achieve dynamo action.« less

46 CFR 166.10 - Course of study for engineering students.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Course of study for engineering students. 166.10 Section... AND APPROVAL OF NAUTICAL SCHOOL SHIPS § 166.10 Course of study for engineering students. The course of study for engineering students shall include (a) all the instruction necessary to fully equip the...

46 CFR 166.10 - Course of study for engineering students.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Course of study for engineering students. 166.10 Section... AND APPROVAL OF NAUTICAL SCHOOL SHIPS § 166.10 Course of study for engineering students. The course of study for engineering students shall include (a) all the instruction necessary to fully equip the...

46 CFR 166.10 - Course of study for engineering students.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Course of study for engineering students. 166.10 Section... AND APPROVAL OF NAUTICAL SCHOOL SHIPS § 166.10 Course of study for engineering students. The course of study for engineering students shall include (a) all the instruction necessary to fully equip the...

46 CFR 166.10 - Course of study for engineering students.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Course of study for engineering students. 166.10 Section... AND APPROVAL OF NAUTICAL SCHOOL SHIPS § 166.10 Course of study for engineering students. The course of study for engineering students shall include (a) all the instruction necessary to fully equip the...

46 CFR 166.10 - Course of study for engineering students.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Course of study for engineering students. 166.10 Section... AND APPROVAL OF NAUTICAL SCHOOL SHIPS § 166.10 Course of study for engineering students. The course of study for engineering students shall include (a) all the instruction necessary to fully equip the...

Platelet-rich plasma to improve the bio-functionality of biomaterials.

PubMed

Anitua, Eduardo; Tejero, Ricardo; Alkhraisat, Mohammad H; Orive, Gorka

2013-04-01

Growth factors and cytokines are active players in controlling the different stages of wound healing and tissue regeneration. Recent trends in personalized regenerative medicine involve using patient's own platelet-rich plasma for stimulating wound healing and tissue regeneration. This technology provides a complex cocktail of growth factors and even a fibrin scaffold with multiple biologic effects. In the last few years, an increasing number of studies provide evidence of the potential of combining platelet-rich plasma with different biomaterials in order to improve their properties, including handling, administration, bioactivity, and level of osseointegration, among others. In this review, we discuss the use of platelet-rich plasma as an alternative, easy, cost-effective, and controllable strategy for the release of high concentrations of many endogenous growth factors. Additionally, we provide an overview of the current progress and future directions of research combining different types of biomaterials with platelet-rich plasma in tissue engineering and regenerative medicine.

Study of Pulsed vs. RF Plasma Properties for Surface Processing Applications

NASA Astrophysics Data System (ADS)

Tang, Ricky; Hopkins, Matthew; Barnat, Edward; Miller, Paul

2015-09-01

The ability to manipulate the plasma parameters (density, E/N) was previously demonstrated using a double-pulsed column discharge. Experiments extending this to large-surface plasmas of interest to the plasma processing community were conducted. Differences between an audio-frequency pulsed plasma and a radio-frequency (rf) discharge, both prevalent in plasma processing applications, were studied. Optical emission spectroscopy shows higher-intensity emission in the UV/visible range for the pulsed plasma comparing to the rf plasma at comparable powers. Data suggest that the electron energy is higher for the pulsed plasma leading to higher ionization, resulting in increased ion density and ion flux. Diode laser absorption measurements of the concentration of the 1S5 metastable and 1S4 resonance states of argon (correlated with the plasma E/N) provide comparisons between the excitation/ionization states of the two plasmas. Preliminary modeling efforts suggest that the low-frequency polarity switch causes a much more abrupt potential variation to support interesting transport phenomena, generating a ``wave'' of higher temperature electrons leading to more ionization, as well as ``sheath capture'' of a higher density bolus of ions that are then accelerated during polarity switch.

Laser-Induced Plasma Chemistry of the Explosive RDX with Various Metals

DTIC Science & Technology

2011-07-18

U.S. Army Research, Development and Engineering Command Laser-induced plasma chemistry of the explosive RDX with various metals Jennifer L...2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Laser-induced plasma chemistry of the explosive RDX with...followed by laser-induced plasma chemistry Time-resolved emission spectra Laser Parameters Laser pulse energy dependence Single vs. double pulse

Numerical band structure calculations of plasma metamaterials

NASA Astrophysics Data System (ADS)

Pederson, Dylan; Kourtzanidis, Konstantinos; Raja, Laxminarayan

2015-09-01

Metamaterials (MM) are materials engineered to display negative macroscopic permittivity and permeability. These materials allow for designed control over electromagnetic energy flow, especially at frequencies where natural materials do not interact. Plasmas have recently found application in MM as a negative permittivity component. The permittivity of a plasma depends on its electron density, which can be controlled by an applied field. This means that plasmas can be used in MM to actively control the transmission or reflection of incident waves. This work focuses on a plasma MM geometry in which microplasmas are generated in perforations in a metal plate. We characterizethis material by its band structure, which describes its interaction with incident waves. The plasma-EM interactions are obtained by coupling Maxwell's equations to a simplified plasma momentum equation. A plasma density profile is prescribed, and its effect on the band structure is investigated. The band structure calculations are typically done for static structures, whereas our current density responds to the incident waves. The resulting band structures are compared with experimental results.

Women in Engineering Education. Studies in Engineering Education 12.

ERIC Educational Resources Information Center

Michel, Jean

Engineering in higher education has the lowest proportion of women students when compared with other fields of study. This book discusses the issues and problems that face the training and promotion of women at the university level. Part one discusses the background and trends of female participation in different regions and disciplines of higher…

Runaway electrons and mitigation studies in MST tokamak plasmas

NASA Astrophysics Data System (ADS)

Goetz, J. A.; Chapman, B. E.; Almagri, A. F.; Cornille, B. S.; Dubois, A.; McCollam, K. J.; Munaretto, S.; Sovinec, C. R.

2016-10-01

Studies of runaway electrons generated in low-density MST tokamak plasmas are being undertaken. The plasmas have Bt <= 0.14 T, Ip <= 50 kA, q (a) = 2.2 , and an electron density and temperature of about 5 ×1017m-3 and 150 eV. Runaway electrons are detected via x-ray bremsstrahlung emission. The density and electric field thresholds for production and suppression have been previously explored with variations in gas puffing for density control. Runaway electrons are now being probed with resonant magnetic perturbations (RMP's). An m = 3 RMP strongly suppresses the runaway electrons and initial NIMROD modeling shows that this may be due to degradation of flux surfaces. The RMP is produced by a poloidal array of 32 saddle coils at the narrow vertical insulated cut in MST's thick conducting shell, with each RMP having a single m but a broad n spectrum. While a sufficiently strong m = 3 RMP suppresses the runaway electrons, an RMP with m = 1 and comparable amplitude has little effect. The impact of the RMP's on the magnetic topology of these plasmas is being studied with the nonlinear MHD code NIMROD. With an m = 3 RMP, stochasticity is introduced in the outer third of the plasma but no such flux surface degradation is observed with an m = 1 RMP. NIMROD also predicts regularly occurring MHD activity similar to that observed in the experiment. These studies have also been done in q (a) = 2.7 plasmas and analysis and modeling is ongoing. This work supported by USDoE.

Studies on the transmission of sub-THz waves in magnetized inhomogeneous plasma sheath

NASA Astrophysics Data System (ADS)

Yuan, Kai; Shen, Linfang; Yao, Ming; Deng, Xiaohua; Chen, Zhou; Hong, Lujun

2018-01-01

There have been many studies on the sub-terahertz (sub-THz) wave transmission in reentry plasma sheaths. However, only some of them have paid attention to the transmission of sub-THz waves in magnetized plasma sheaths. In this paper, the transmission of sub-THz waves in both unmagnetized and magnetized reentry plasma sheaths was investigated. The impacts of temporal evolution of the plasma sheath on the wave transmission were studied. The transmission of "atmospheric window" frequencies in a magnetized plasma sheath was discussed in detail. According to the study, the power transmission rates (Tp) for the left hand circular (LHC) and the right hand circular modes in the magnetized plasma sheath are obviously higher and lower than those in the unmagnetized plasma sheath, respectively. The Tp of LHC mode increases with both wave frequency and external magnetic field strength. Also, the Tp of LHC mode in both magnetized and unmagnetized plasma sheaths varies with time due to the temporal evolution of the plasma sheath. Moreover, the performance of sub-THz waves in magnetized plasma sheath hints at a new approach to the "blackout" problem. The new approach, which is in the capability of modern technology, is to utilize the communication system operating at 140 GHz with an onboard magnet installed near the antenna.

Plasma characterization studies for materials processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pfender, E.; Heberlein, J.

New applications for plasma processing of materials require a more detailed understanding of the fundamental processes occurring in the processing reactors. We have developed reactors offering specific advantages for materials processing, and we are using modeling and diagnostic techniques for the characterization of these reactors. The emphasis is in part set by the interest shown by industry pursuing specific plasma processing applications. In this paper we report on the modeling of radio frequency plasma reactors for use in materials synthesis, and on the characterization of the high rate diamond deposition process using liquid precursors. In the radio frequency plasma torchmore » model, the influence of specific design changes such as the location of the excitation coil on the enthalpy flow distribution is investigated for oxygen and air as plasma gases. The diamond deposition with liquid precursors has identified the efficient mass transport in form of liquid droplets into the boundary layer as responsible for high growth, and the chemical properties of the liquid for the film morphology.« less

A multicenter study of plasma use in the United States

PubMed Central

Triulzi, Darrell; Gottschall, Jerome; Murphy, Edward; Wu, Yanyun; Ness, Paul; Kor, Daryl; Roubinian, Nareg; Fleischmann, Debra; Chowdhury, Dhuly; Brambilla, Donald

2016-01-01

Background Detailed information regarding plasma use in the United States is needed to identify opportunities for practice improvement and design of clinical trials of plasma therapy. Study Design and Methods Ten US hospitals collected detailed medical information from the electronic health records for 1 year (2010-2011) for all adult patients transfused with plasma. Results A total of 72,167 units of plasma were transfused in 19,596 doses to 9269 patients. The median dose of plasma was 2 units (interquartile range, 2-4; range 1-72); 15% of doses were 1 unit, and 45% were 2 units. When adjusted by patient body weight (kg), the median dose was 7.3 mL/kg (interquartile range, 5.5-12.0). The median pretransfusion international normalized ratio (INR) was 1.9 (25%-75% interquartile range, 1.6-2.6). A total of 22.5% of plasma transfusions were given to patients with an INR of less than 1.6 and 48.5% for an INR of 2.0 or more. The median posttransfusion INR was 1.6 (interquartile range, 1.4-2.0). Only 42% of plasma transfusions resulted in a posttransfusion INR of less than 1.6. Correction of INR increased as the plasma dose increased from 1 to 4 units (p < 0.001). There was no difference in the INR response to different types of plasma. The most common issue locations were general ward (38%) and intensive care unit (ICU; 42%). Conclusion This large database describing plasma utilization in the United States provides evidence for both inadequate dosing and unnecessary transfusion. Measures to improve plasma transfusion practice and clinical trials should be directed at patients on medical and surgical wards and in the ICU where plasma is most commonly used. PMID:25522888

Transport studies in high-performance field reversed configuration plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, S., E-mail: sgupta@trialphaenergy.com; Barnes, D. C.; Dettrick, S. A.

2016-05-15

A significant improvement of field reversed configuration (FRC) lifetime and plasma confinement times in the C-2 plasma, called High Performance FRC regime, has been observed with neutral beam injection (NBI), improved edge stability, and better wall conditioning [Binderbauer et al., Phys. Plasmas 22, 056110 (2015)]. A Quasi-1D (Q1D) fluid transport code has been developed and employed to carry out transport analysis of such C-2 plasma conditions. The Q1D code is coupled to a Monte-Carlo code to incorporate the effect of fast ions, due to NBI, on the background FRC plasma. Numerically, the Q1D transport behavior with enhanced transport coefficients (butmore » with otherwise classical parametric dependencies) such as 5 times classical resistive diffusion, classical thermal ion conductivity, 20 times classical electron thermal conductivity, and classical fast ion behavior fit with the experimentally measured time evolution of the excluded flux radius, line-integrated density, and electron/ion temperature. The numerical study shows near sustainment of poloidal flux for nearly 1 ms in the presence of NBI.« less

Study of ND3-enhanced MAR processes in D2-N2 plasmas to induce plasma detachment

NASA Astrophysics Data System (ADS)

Abe, Shota; Chakraborty Thakur, Saikat; Doerner, Russ; Tynan, George

2017-10-01

The Molecular Assisted Recombination (MAR) process is thought to be a main channel of volumetric recombination to induce the plasma detachment operation. Authors have focused on a new plasma recombination process supported by ammonia molecules, which will be formed by impurity seeding of N2 for controlling divertor plasma temperature and heat loads in ITER. This ammonia-enhanced MAR process would occur throughout two steps. In this study, the first step of the new MAR process is investigated in low density plasmas (Ne 1016 m-3, Te 4 eV) fueled by D2 and N2. Ion and neutral densities are measured by a calibrated Electrostatic Quadrupole Plasma (EQP) analyzer, combination of an ion energy analyzer and mass spectrometer. The EQP shows formation of ND3 during discharges. Ion densities calculated by a rate equation model are compared with experimental results. We find that the model can reproduce the observed ion densities in the plasma. The model calculation shows that the dominant neutralization channel of Dx+(x =1-3) ions in the volume is the formation of NDy+(y =3 or 4) throughout charge/D+ exchange reactions with ND3. Furthermore, high density plasmas (Ne 1016 m-3) have been achieved to investigate electron-impact dissociative recombination processes of formed NDy+,which is the second step of this MAR process.

Evolution of streamer groups in nonthermal plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okubo, M., E-mail: mokubo@me.osakafu-u.ac.jp

2015-12-15

Nonthermal plasmas (NTPs) induced by atmospheric nanosecond pulsed corona discharge have been studied for controlling pollution from combustors, such as boilers, incinerators, and diesel engines. In high-speed short-width high-voltage pulsed corona discharge-induced plasmas, primary streamer evolution is followed by secondary streamer evolution. Though this phenomenon is known experimentally, the details of the structures of the streamers and their evolution mechanisms have not been fully clarified. In this letter, we perform quasi two-dimensional numerical analysis of nonequilibrium NTP induced by a nanosecond positive pulsed corona discharge. The continuum fluid equations for two-temperature nonequilibrium NTP are used as governing equations. In thismore » study, 197 gas phase reactions for 25 chemical species and 21 surface reactions on the inner glass wall surface are considered in an air plasma under atmospheric pressure. The simulated behavior of the streamer groups agrees with experimental observations. Soon after the voltage increases on the reactor, primary streamers are formed, which may transit the complete gap, disappearing near the peak voltage. Next, second streamers appear, disappearing at the end of the applied voltage pulse. The streamer wavelength and the distance between the streamers in the axial direction are determined. Moreover, ozone generation is shown to be more significant in the secondary streamer. This simulation will allow better predictions for nanosecond positive pulsed plasma systems.« less

Evolution of streamer groups in nonthermal plasma

NASA Astrophysics Data System (ADS)

Okubo, M.

2015-12-01

Nonthermal plasmas (NTPs) induced by atmospheric nanosecond pulsed corona discharge have been studied for controlling pollution from combustors, such as boilers, incinerators, and diesel engines. In high-speed short-width high-voltage pulsed corona discharge-induced plasmas, primary streamer evolution is followed by secondary streamer evolution. Though this phenomenon is known experimentally, the details of the structures of the streamers and their evolution mechanisms have not been fully clarified. In this letter, we perform quasi two-dimensional numerical analysis of nonequilibrium NTP induced by a nanosecond positive pulsed corona discharge. The continuum fluid equations for two-temperature nonequilibrium NTP are used as governing equations. In this study, 197 gas phase reactions for 25 chemical species and 21 surface reactions on the inner glass wall surface are considered in an air plasma under atmospheric pressure. The simulated behavior of the streamer groups agrees with experimental observations. Soon after the voltage increases on the reactor, primary streamers are formed, which may transit the complete gap, disappearing near the peak voltage. Next, second streamers appear, disappearing at the end of the applied voltage pulse. The streamer wavelength and the distance between the streamers in the axial direction are determined. Moreover, ozone generation is shown to be more significant in the secondary streamer. This simulation will allow better predictions for nanosecond positive pulsed plasma systems.

Study on dynamics of the influence exerted by plasma on gas flow field in non-thermal atmospheric pressure plasma jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qaisrani, M. Hasnain; Xian, Yubin, E-mail: yubin.xian@hotmail.com; Li, Congyun

2016-06-15

In this paper, first, steady state of the plasma jet at different operating conditions is investigated through Schlieren photography with and without applying shielding gas. Second, the dynamic process for the plasma impacting on the gas flow field is studied. When the discharge is ignited, reduction in laminar flow occurs. However, when the gas flow rate is too low or too high, this phenomenon is not obvious. What is more, both frequency and voltage have significant impact on the effect of plasma on the gas flow, but the former is more significant. Shielding gas provides a curtain for plasma tomore » propagate further. High speed camera along with Schlieren photography is utilized to study the impact of plasma on the gas flow when plasma is switched on and off. The transition of the gas flow from laminar to turbulent or vice versa happens right after the turbulent front. It is concluded that appearance and propagation of turbulence front is responsible for the transition of the flow state.« less

Potential Industrial Applications of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) Operating in Ambient Air

NASA Astrophysics Data System (ADS)

Reece Roth, J.

2004-11-01

The majority of industrial plasma processing with glow discharges has been conducted at pressures below 10 torr. This tends to limit applications to high value workpieces as a result of the high capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharge plasmas would play a much larger industrial role if they could be generated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP), developed at the University of Tennessee's Plasma Sciences Laboratory, is a non-thermal RF plasma operating on displacement currents with the time-resolved characteristics of a classical low pressure DC normal glow discharge. As a glow discharge, the OAUGDP operates with maximum electrical efficiency at the Stoletow point, where the energy input per ion-electron pair is a minimum [1, 2]. Several interdisciplinary teams have investigated potential applications of the OAUGDP. These teams included collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC), and the Departments of Electrical and Computer Engineering, Microbiology, and Food Science and Technology, as well as the NASA Langley Research Center. The potential applications of the OAUGDP have all been at one atmosphere and room temperature, using air as the working gas. These applications include sterilizing medical and dental equipment; sterilizable air filters to deal with the "sick building syndrome"; removal of soot from Diesel engine exhaust; subsonic plasma aerodynamic effects, including flow re-attachment to airfoils and boundary layer modification; electrohydrodynamic (EDH) flow control of working gases; increasing the surface energy of materials; improving the adhesion of paints and electroplated layers: improving the wettability and wickability of fabrics; stripping of photoresist; and plasma deposition and directional etching of potential microelectronic relevance. [1] J. R. Roth, Industrial Plasma Engineering

Immunochemical Studies of Plasma Kallikrein

PubMed Central

Bagdasarian, Andranik; Lahiri, Biswajit; Talamo, Richard C.; Wong, Pat; Colman, Robert W.

1974-01-01

A monospecific antibody against human plasma kallikrein has been prepared in rabbits with kallikrein further purified to remove gamma globulins. The antisera produced contained antikallikrein and also anti-IgG, in spite of only 8% contamination of kallikrein preparation with IgG. The latter antibody was removed by adsorption of antisera with either Fletcher factor-deficient plasma or with purified IgG. Both kallikrein and prekallikrein (in plasma) cross-react with the antibody with no apparent difference between the precipitation arcs developed during immunoelectrophoresis and no significant difference in reactivity when quantified by radial immunodiffusion. Kallikrein antibody partially inhibits the esterolytic and fully inhibits the proteolytic activity of kallikrein. In addition, the antibody inhibits the activation of prekallikrein, as measured by esterase or kinin release. The magnitude of the inhibition is related to the molecular weight of the activator used. Thus, for the four activators tested, the greatest inhibition is observed with kaolin and factor XIIA, while large activator and the low molecular weight prekallikrein activators are less inhibited. With the kallikrein antibody, the incubation of kallikrein with either plasma or partially purified C1 esterase inactivator results in a new precipitin arc, as detected by immunoelectrophoresis. This finding provides physical evidence for the interaction of the enzyme and inhibitor. No new arc could be demonstrated between kallikrein and α2-macroglobulin, or α1-antitrypsin, although the concentration of free kallikrein antigen decreases after interaction with the former inhibitor. By radial immunodiffusion, plasma from healthy individuals contained 103±13 μg/ml prekallikrein antigen. Although in mild liver disease, functional and immunologic kallikrein are proportionally depressed, the levels of prekallikrein antigen in plasma samples from patients with severe liver disease remains 40% of normal, while

Interdisciplinary Research Topics in Urban Engineering. (A Summary of the Report by the Urban Engineering Study Committee)

ERIC Educational Resources Information Center

Eng Educ, 1969

1969-01-01

Proposes preparation of urban engineers through interdisciplinary systems engineering research in order that technology may be applied to urban problems such as transportation, environment, and housing. Summary of report by the Urban Engineering Study Committee. Complete report available at

Plasma physics of extreme astrophysical environments.

PubMed

Uzdensky, Dmitri A; Rightley, Shane

2014-03-01

Among the incredibly diverse variety of astrophysical objects, there are some that are characterized by very extreme physical conditions not encountered anywhere else in the Universe. Of special interest are ultra-magnetized systems that possess magnetic fields exceeding the critical quantum field of about 44 TG. There are basically only two classes of such objects: magnetars, whose magnetic activity is manifested, e.g., via their very short but intense gamma-ray flares, and central engines of supernovae (SNe) and gamma-ray bursts (GRBs)--the most powerful explosions in the modern Universe. Figuring out how these complex systems work necessarily requires understanding various plasma processes, both small-scale kinetic and large-scale magnetohydrodynamic (MHD), that govern their behavior. However, the presence of an ultra-strong magnetic field modifies the underlying basic physics to such a great extent that relying on conventional, classical plasma physics is often not justified. Instead, plasma-physical problems relevant to these extreme astrophysical environments call for constructing relativistic quantum plasma (RQP) physics based on quantum electrodynamics (QED). In this review, after briefly describing the astrophysical systems of interest and identifying some of the key plasma-physical problems important to them, we survey the recent progress in the development of such a theory. We first discuss the ways in which the presence of a super-critical field modifies the properties of vacuum and matter and then outline the basic theoretical framework for describing both non-relativistic and RQPs. We then turn to some specific astrophysical applications of relativistic QED plasma physics relevant to magnetar magnetospheres and to central engines of core-collapse SNe and long GRBs. Specifically, we discuss the propagation of light through a magnetar magnetosphere; large-scale MHD processes driving magnetar activity and responsible for jet launching and propagation in

Studies of Fission Fragment Rocket Engine Propelled Spacecraft

NASA Technical Reports Server (NTRS)

Werka, Robert O.; Clark, Rodney; Sheldon, Rob; Percy, Thomas K.

2014-01-01

The NASA Office of Chief Technologist has funded from FY11 through FY14 successive studies of the physics, design, and spacecraft integration of a Fission Fragment Rocket Engine (FFRE) that directly converts the momentum of fission fragments continuously into spacecraft momentum at a theoretical specific impulse above one million seconds. While others have promised future propulsion advances if only you have the patience, the FFRE requires no waiting, no advances in physics and no advances in manufacturing processes. Such an engine unequivocally can create a new era of space exploration that can change spacecraft operation. The NIAC (NASA Institute for Advanced Concepts) Program Phase 1 study of FY11 first investigated how the revolutionary FFRE technology could be integrated into an advanced spacecraft. The FFRE combines existent technologies of low density fissioning dust trapped electrostatically and high field strength superconducting magnets for beam management. By organizing the nuclear core material to permit sufficient mean free path for escape of the fission fragments and by collimating the beam, this study showed the FFRE could convert nuclear power to thrust directly and efficiently at a delivered specific impulse of 527,000 seconds. The FY13 study showed that, without increasing the reactor power, adding a neutral gas to the fission fragment beam significantly increased the FFRE thrust through in a manner analogous to a jet engine afterburner. This frictional interaction of gas and beam resulted in an engine that continuously produced 1000 pound force of thrust at a delivered impulse of 32,000 seconds, thereby reducing the currently studied DRM 5 round trip mission to Mars from 3 years to 260 days. By decreasing the gas addition, this same engine can be tailored for much lower thrust at much higher impulse to match missions to more distant destinations. These studies created host spacecraft concepts configured for manned round trip journeys. While the

Study of Plasma Chemistry and Plasma Processing.

DTIC Science & Technology

1983-01-01

m, 20% 0,0-oxybisfpropionitrile] on Chrom W column in these reactions comes from their pertinence to prebiotic was used for cyanogen and gaseous...xerography, prebiotic chemistry, and chemistry in the ionosphere. L -5- Euipment for RF Reactions Virtually all of the work on organic plasmas has used RF

A Historical Systems Study of Liquid Rocket Engine Throttling Capabilities

NASA Technical Reports Server (NTRS)

Betts, Erin M.; Frederick, Robert A., Jr.

2010-01-01

This is a comprehensive systems study to examine and evaluate throttling capabilities of liquid rocket engines. The focus of this study is on engine components, and how the interactions of these components are considered for throttling applications. First, an assessment of space mission requirements is performed to determine what applications require engine throttling. A background on liquid rocket engine throttling is provided, along with the basic equations that are used to predict performance. Three engines are discussed that have successfully demonstrated throttling. Next, the engine system is broken down into components to discuss special considerations that need to be made for engine throttling. This study focuses on liquid rocket engines that have demonstrated operational capability on American space launch vehicles, starting with the Apollo vehicle engines and ending with current technology demonstrations. Both deep throttling and shallow throttling engines are discussed. Boost and sustainer engines have demonstrated throttling from 17% to 100% thrust, while upper stage and lunar lander engines have demonstrated throttling in excess of 10% to 100% thrust. The key difficulty in throttling liquid rocket engines is maintaining an adequate pressure drop across the injector, which is necessary to provide propellant atomization and mixing. For the combustion chamber, cooling can be an issue at low thrust levels. For turbomachinery, the primary considerations are to avoid cavitation, stall, surge, and to consider bearing leakage flows, rotordynamics, and structural dynamics. For valves, it is necessary to design valves and actuators that can achieve accurate flow control at all thrust levels. It is also important to assess the amount of nozzle flow separation that can be tolerated at low thrust levels for ground testing.

A source to deliver mesoscopic particles for laser plasma studies

NASA Astrophysics Data System (ADS)

Gopal, R.; Kumar, R.; Anand, M.; Kulkarni, A.; Singh, D. P.; Krishnan, S. R.; Sharma, V.; Krishnamurthy, M.

2017-02-01

Intense ultrashort laser produced plasmas are a source for high brightness, short burst of X-rays, electrons, and high energy ions. Laser energy absorption and its disbursement strongly depend on the laser parameters and also on the initial size and shape of the target. The ability to change the shape, size, and material composition of the matter that absorbs light is of paramount importance not only from a fundamental physics point of view but also for potentially developing laser plasma sources tailored for specific applications. The idea of preparing mesoscopic particles of desired size/shape and suspending them in vacuum for laser plasma acceleration is a sparsely explored domain. In the following report we outline the development of a delivery mechanism of microparticles into an effusive jet in vacuum for laser plasma studies. We characterise the device in terms of particle density, particle size distribution, and duration of operation under conditions suitable for laser plasma studies. We also present the first results of x-ray emission from micro crystals of boric acid that extends to 100 keV even under relatively mild intensities of 1016 W/cm2.

Plasma reforming and partial oxidation of hydrocarbon fuel vapor to produce synthesis gas and/or hydrogen gas

DOEpatents

Kong, Peter C.; Detering, Brent A.

2003-08-19

Methods and systems for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

Automobile Engine Control Parameters Study : Volume 1. Summary and Status of Domestic Engine Control Practice

DOT National Transportation Integrated Search

1977-02-01

This report contains the results of a study to evaluate automobile engine control parameters and their effects on vehicle fuel economy and emissions. Volume I presents detailed technical information on the engine control practices used by selected do...

Kinetic Studies of Nonequilibrium Plasma-Assisted Combustion

DTIC Science & Technology

2010-02-25

resolved air plasma temperatures inferred from both N2 second positive emission spectroscopy and CARS, along with plasma chemistry model predictions...nanosecond discharge in air and in ethylene-air (O=0.1 and 0=1.0) at P=40 torr with the plasma chemistry model prediction. Figure 5 compares the CARS...1 1 .(1 j. a-IH ) 1 ’ 1 ’ 1 ’ 5 10 15 Time, msec 1 20 1 25 Figure 6: Plasma chemistry model predictions for O

Near Real Time Tools for ISS Plasma Science and Engineering Applications

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Willis, Emily M.; Parker, Linda Neergaard; Shim, Ja Soon; Kuznetsova, Maria M.; Pulkkinen, Antti, A.

2013-01-01

The International Space Station (ISS) program utilizes a plasma environment forecast for estimating electrical charging hazards for crews during extravehicular activity (EVA). The process uses ionospheric electron density (Ne) and temperature (Te) measurements from the ISS Floating Potential Measurement Unit (FPMU) instrument suite with the assumption that the plasma conditions will remain constant for one to fourteen days with a low probability for a space weather event which would significantly change the environment before an EVA. FPMU data is typically not available during EVA's, therefore, the most recent FPMU data available for characterizing the state of the ionosphere during EVA is typically a day or two before the start of an EVA or after the EVA has been completed. Three near real time space weather tools under development for ISS applications are described here including: (a) Ne from ground based ionosonde measurements of foF2 (b) Ne from near real time satellite radio occultation measurements of electron density profiles (c) Ne, Te from a physics based ionosphere model These applications are used to characterize the ISS space plasma environment during EVA periods when FPMU data is not available, monitor for large changes in ionosphere density that could render the ionosphere forecast and plasma hazard assessment invalid, and validate the "persistence of conditions" forecast assumption. In addition, the tools are useful for providing space environment input to science payloads on ISS and anomaly investigations during periods the FPMU is not operating.

Advanced oxygen-hydrocarbon rocket engine study

NASA Technical Reports Server (NTRS)

Obrien, C. J.; Salkeld, R.

1980-01-01

The advantages and disadvantages, system performance and operating limits, engine parametric data, and technology requirements for candidate high pressure LO2/Hydrocarbon engine systems are summarized. These summaries of parametric analysis and design provide a consistent engine system data base. Power balance data were generated for the eleven engine cycles. Engine cycle rating parameters were established and the desired condition and the effect of the parameter on the engine and/or vehicle are described.

Study of Inactivation Factors in Low Temperature Surface-wave Plasma Sterilization

NASA Astrophysics Data System (ADS)

Singh, Mrityunjai Kumar; Xu, Lei; Ogino, Akihisa; Nagatsu, Masaaki

In this study we investigated the low temperature surface-wave plasma sterilization of directly and indirectly exposed Geobacillus stearothermophilus spores with a large-volume microwave plasma device. The air-simulated gas mixture was used to produce the plasma. The water vapor addition to the gas mixture improved the sterilization efficiency significantly. The effect of ultraviolet photons produced along with plasma to inactivate the spores was studied using a separate chamber, which was evacuated to less than one mTorr and was observed that spores were sterilized within 60 min. The scanning electron microscopy images revealed no significant changes in the actual size of the spores with that of untreated spores despite the survival curve shown that the spores were inactivated.

EDITORIAL: Plasma jets and plasma bullets Plasma jets and plasma bullets

NASA Astrophysics Data System (ADS)

Kong, M. G.; Ganguly, B. N.; Hicks, R. F.

2012-06-01

technological solution in the early to late 1990s of confining atmospheric plasmas in a small volume of plasma generation (i.e. with a small volume-to-surface ratio) and then extending it towards a downstream sample [7]-[9]. These are among the first low-temperature atmospheric plasmas aimed particularly at the exploitation of their ability to invoke the active and rich reactive chemistry close to ambient temperature. The main applications of these early devices are precision surface modification of low-temperature dielectric materials, for example thin film deposition and etching [7]-[9]. Variations of the early plasma jets include atmospheric plasma sheet jets [10] for the treatment of largely planar objects (e.g. polymeric sheets) as well as large arrays of many plasma jets for the treatment of complex-structured objects (e.g. surgical tools and open human wounds) [11]. As a material processing technology, the sub-100oC atmospheric-pressure plasma jet has benefited over the years from many innovations. Whilst a detailed account and analysis of these is clearly outside the scope of this Editorial, it is worth stating that there are different avenues with which to maintain a moderate electron density at the plasma core so as to keep the gas temperature at the sample point below a ceiling level. Most of the early studies employed excitation at radio frequencies above 10 MHz, at which electrons are largely confined in the plasma generation region, and this limits the current flow to and gas heating in the plume region of the plasma jet. Other techniques of current limitation have since been shown to be effective, including the use of dielectric barriers across a very large frequency range of 1 kHz--50 MHz, sub-microsecond pulses sustained at kHz frequencies, pulse-modulated radio frequencies and dual-frequency excitation [12]-[15]. These and other techniques have considerably advanced the atmospheric-pressure plasma jet technology. The period of some 15 years since the above

Studies of Particle Wake Potentials in Plasmas

NASA Astrophysics Data System (ADS)

Ellis, Ian; Graziani, Frank; Glosli, James; Strozzi, David; Surh, Michael; Richards, David; Decyk, Viktor; Mori, Warren

2011-10-01

Fast Ignition studies require a detailed understanding of electron scattering, stopping, and energy deposition in plasmas with variable values for the number of particles within a Debye sphere. Presently there is disagreement in the literature concerning the proper description of these processes. Developing and validating proper descriptions requires studying the processes using first-principle electrostatic simulations and possibly including magnetic fields. We are using the particle-particle particle-mesh (PPPM) code ddcMD and the particle-in-cell (PIC) code BEPS to perform these simulations. As a starting point in our study, we examine the wake of a particle passing through a plasma in 3D electrostatic simulations performed with ddcMD and with BEPS using various cell sizes. In this poster, we compare the wakes we observe in these simulations with each other and predictions from Vlasov theory. Prepared by LLNL under Contract DE-AC52-07NA27344 and by UCLA under Grant DE-FG52-09NA29552.

Study of Globus-M Tokamak Poloidal System and Plasma Position Control

NASA Astrophysics Data System (ADS)

Dokuka, V. N.; Korenev, P. S.; Mitrishkin, Yu. V.; Pavlova, E. A.; Patrov, M. I.; Khayrutdinov, R. R.

2017-12-01

In order to provide efficient performance of tokamaks with vertically elongated plasma position, control systems for limited and diverted plasma configuration are required. The accuracy, stability, speed of response, and reliability of plasma position control as well as plasma shape and current control depend on the performance of the control system. Therefore, the problem of the development of such systems is an important and actual task in modern tokamaks. In this study, the measured signals from the magnetic loops and Rogowski coils are used to reconstruct the plasma equilibrium, for which linear models in small deviations are constructed. We apply methods of the H∞-optimization theory to the synthesize control system for vertical and horizontal position of plasma capable to working with structural uncertainty of the models of the plant. These systems are applied to the plasma-physical DINA code which is configured for the tokamak Globus-M plasma. The testing of the developed systems applied to the DINA code with Heaviside step functions have revealed the complex dynamics of plasma magnetic configurations. Being close to the bifurcation point in the parameter space of unstable plasma has made it possible to detect an abrupt change in the X-point position from the top to the bottom and vice versa. Development of the methods for reconstruction of plasma magnetic configurations and experience in designing plasma control systems with feedback for tokamaks provided an opportunity to synthesize new digital controllers for plasma vertical and horizontal position stabilization. It also allowed us to test the synthesized digital controllers in the closed loop of the control system with the DINA code as a nonlinear model of plasma.

Method of fabricating a rocket engine combustion chamber

NASA Technical Reports Server (NTRS)

Holmes, Richard R. (Inventor); Mckechnie, Timothy N. (Inventor); Power, Christopher A. (Inventor); Daniel, Ronald L., Jr. (Inventor); Saxelby, Robert M. (Inventor)

1993-01-01

A process for making a combustion chamber for a rocket engine wherein a copper alloy in particle form is injected into a stream of heated carrier gas in plasma form which is then projected onto the inner surface of a hollow metal jacket having the configuration of a rocket engine combustion chamber is described. The particles are in the plasma stream for a sufficient length of time to heat the particles to a temperature such that the particles will flatten and adhere to previously deposited particles but will not spatter or vaporize. After a layer is formed, cooling channels are cut in the layer, then the channels are filled with a temporary filler and another layer of particles is deposited.

The Diagnostics of the External Plasma for the Plasma Rocket

NASA Technical Reports Server (NTRS)

Karr, Gerald R.

1997-01-01

Three regions of plasma temperature/energy are being investigated to understand fully the behavior of the plasma created by the propulsion device and the operation of the RPA. Each type of plasma has a RPA associated with it; i.e. a thermal RPA, a collimated RPA, and a high temperature RPA. Through the process of developing the thermal and collimated RPAs, the proper knowledge and experience has been gained to not only design a high temperature RPA for the plasma rocket, but to understand its operation, results, and uncertainty. After completing a literature search for, reading published papers on, and discussing the operation of the RPA with electric propulsion researchers, I applied the knowledge gained to the development of a RPA for thermal plasma. A design of a thermal RPA was made which compensates for a large Debye length and low ionized plasma. From this design a thermal RPA was constructed. It consists of an outer stainless steel casing, a phenolic insulator (outgases slightly), and stainless steel mesh for the voltage screens. From the experience and knowledge gained in the development of the thermal RPA, a RPA for collimated plasma was developed. A collimated RPA has been designed and constructed. It compensate for a smaller Debye length and much higher ionization than that existing in the thermal plasma. It is 17% of the size of the thermal RPA. A stainless steel casing shields the detector from impinging electrons and ions. An insulating material, epoxy resin, was utilized which has a negligible outgassing. This material can be molded in styrofoam and machined quite nicely. It is capable of withstanding moderately high temperatures. Attached to this resin insulator are inconel screens attached by silver plated copper wire to a voltage supply. All the work on the RPAs and thermal ion source, I performed in the University of Alabama in Huntsville's (UAH) engineering machine shop.

Experimental investigation on laser-induced plasma ignition of hydrocarbon fuel in scramjet engine at takeover flight conditions

NASA Astrophysics Data System (ADS)

Li, Xipeng; Liu, Weidong; Pan, Yu; Yang, Leichao; An, Bin

2017-09-01

Laser-induced plasma ignition of an ethylene fuelled cavity is successfully conducted in a model scramjet engine combustor with dual cavities. The simulated flight condition corresponds to takeover flight Mach 4, with isolator entrance Mach number of 2.1, the total pressure of 0.65 MPa and stagnation temperature of 947 K. Ethylene is injected 35 mm upstream of cavity flameholder from four orifices with 2-mm-diameter. The 1064 nm laser beam, from a Q-switched Nd:YAG laser source running at 10 Hz and 940 mJ per pulse, is focused into cavity for ignition. High speed photography is used to capture the transient ignition process. The laser-induced gas breakdown, flame kernel generation and propagation are all recorded and ensuing stable supersonic combustion is established in cavity. The highly ionized plasma zone is almost round at starting, and then the surface of the flame kernel is wrinkled severely in 150 μs after the laser pulse due to the strong turbulence flow in cavity. The flame kernel is found rotating anti-clockwise and gradually moves upstream as the entrainment of circulation flow in cavity. The flame is stabilized at the corner of the cavity for about 200 μs, and then spreads from leading edge to trailing edge via the under part of shear layer to fully fill the entire cavity. The corner recirculation zone of cavity is of great importance for flame spreading. Eventually, a cavity shear-layer stabilized combustion is established in the supersonic flow roughly 2.9 ms after the laser pulse. Both the temporal evolution of normalized chemiluminescence intensity and normalized flame area show that the entire ignition process can be divided into four stages, which are referred as turbulent dissipation stage, combustion enhancement stage, reverting stage and combustion stabilization stage. The results show promising potentials of laser induced plasma for ignition in real scramjets.

Application of Laser Plasma Sources of Soft X-rays and Extreme Ultraviolet (EUV) in Imaging, Processing Materials and Photoionization Studies

NASA Astrophysics Data System (ADS)

Fiedorowicz, H.; Bartnik, A.; Wachulak, P. W.; Jarocki, R.; Kostecki, J.; Szczurek, M.; Ahad, I. U.; Fok, T.; Szczurek, A.; Wȩgrzyński, Ł.

In the paper we present new applications of laser plasma sources of soft X-rays and extreme ultraviolet (EUV) in various areas of plasma physics, nanotechnology and biomedical engineering. The sources are based on a gas puff target irradiated with nanosecond laser pulses from commercial Nd: YAG lasers, generating pulses with time duration from 1 to 10 ns and energies from 0.5 to 10 J at a 10 Hz repetition rate. The targets are produced with the use of a double valve system equipped with a special nozzle to form a double-stream gas puff target which allows for high conversion efficiency of laser energy into soft X-rays and EUV without degradation of the nozzle. The sources are equipped with various optical systems to collect soft X-ray and EUV radiation and form the radiation beam. New applications of these sources in imaging, including EUV tomography and soft X-ray microscopy, processing of materials and photoionization studies are presented.

Advanced Technology Spark-Ignition Aircraft Piston Engine Design Study

NASA Technical Reports Server (NTRS)

Stuckas, K. J.

1980-01-01

The advanced technology, spark ignition, aircraft piston engine design study was conducted to determine the improvements that could be made by taking advantage of technology that could reasonably be expected to be made available for an engine intended for production by January 1, 1990. Two engines were proposed to account for levels of technology considered to be moderate risk and high risk. The moderate risk technology engine is a homogeneous charge engine operating on avgas and offers a 40% improvement in transportation efficiency over present designs. The high risk technology engine, with a stratified charge combustion system using kerosene-based jet fuel, projects a 65% improvement in transportation efficiency. Technology enablement program plans are proposed herein to set a timetable for the successful integration of each item of required advanced technology into the engine design.

Behavior of an indigenously fabricated transferred arc plasma furnace for smelting studies

NASA Astrophysics Data System (ADS)

A, K. MANDAL; R, K. DISHWAR; O, P. SINHA

2018-03-01

The utilization of industrial solid waste for metal recovery requires high-temperature tools due to the presence of silica and alumina, which is reducible at high temperature. In a plasma arc furnace, transferred arc plasma furnace (TAP) can meet all requirements, but the disadvantage of this technology is the high cost. For performing experiments in the laboratory, the TAP was fabricated indigenously in a laboratory based on the different inputs provided in the literature for the furnace design and fabrication. The observed parameters such as arc length, energy consumption, graphite electrode consumption, noise level as well as lining erosion were characterized for this fabricated furnace. The nitrogen plasma increased by around 200 K (200 °C) melt temperature and noise levels decreased by ∼10 dB compared to a normal arc. Hydrogen plasma offered 100 K (100 °C) higher melt temperature with ∼5 dB higher sound level than nitrogen plasma. Nitrogen plasma arc melting showed lower electrode and energy consumption than normal arc melting, whereas hydrogen plasma showed lower energy consumption and higher electrode consumption in comparison to nitrogen plasma. The higher plasma arc temperature resulted in a shorter meltdown time than normal arc with smoother arcing. Hydrogen plasma permitted more heats, reduced meltdown time, and lower energy consumption, but with increased graphite consumption and crucible wear. The present study showed that the fabricated arc plasma is better than the normal arc furnace with respect to temperature generation, energy consumption, and environmental friendliness. Therefore, it could be used effectively for smelting-reduction studies.

Study of Volumetrically Heated Ultra-High Energy Density Plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocca, Jorge J.

2016-10-27

Heating dense matter to millions of degrees is important for applications, but requires complex and expensive methods. The major goal of the project was to demonstrate using a compact laser the creation of a new ultra-high energy density plasma regime characterized by simultaneous extremely high temperature and high density, and to study it combining experimental measurements and advanced simulations. We have demonstrated that trapping of intense femtosecond laser pulses deep within ordered nanowire arrays can heat near solid density matter into a new ultra hot plasma regime. Extreme electron densities, and temperatures of several tens of million degrees were achievedmore » using laser pulses of only 0.5 J energy from a compact laser. Our x-ray spectra and simulations showed that extremely highly ionized plasma volumes several micrometers in depth are generated by irradiation of gold and Nickel nanowire arrays with femtosecond laser pulses of relativistic intensities. We obtained extraordinarily high degrees of ionization (e.g. we peeled 52 electrons from gold atoms, and up to 26 electrons from nickel atoms). In the process we generated Gigabar pressures only exceeded in the central hot spot of highly compressed thermonuclear fusion plasmas.. The plasma created after the dissolved wires expand, collide, and thermalize, is computed to have a thermal energy density of 0.3 GJ cm -3 and a pressure of 1-2 Gigabar. These are pressures only exceeded in highly compressed thermonuclear fusion plasmas. Scaling these results to higher laser intensities promises to create plasmas with temperatures and pressures exceeding those in the center of the sun.« less

Vacuum plasma spray coating

NASA Technical Reports Server (NTRS)

Holmes, Richard R.; Mckechnie, Timothy N.

1989-01-01

Currently, protective plasma spray coatings are applied to space shuttle main engine turbine blades of high-performance nickel alloys by an air plasma spray process. Originally, a ceramic coating of yttria-stabilized zirconia (ZrO2.12Y2O3) was applied for thermal protection, but was removed because of severe spalling. In vacuum plasma spray coating, plasma coatings of nickel-chromium-aluminum-yttrium (NiCrAlY) are applied in a reduced atmosphere of argon/helium. These enhanced coatings showed no spalling after 40 MSFC burner rig thermal shock cycles between 927 C (1700 F) and -253 C (-423 F), while current coatings spalled during 5 to 25 test cycles. Subsequently, a process was developed for applying a durable thermal barrier coating of ZrO2.8Y2O3 to the turbine blades of first-stage high-pressure fuel turbopumps utilizing the enhanced NiCrAlY bond-coating process. NiCrAlY bond coating is applied first, with ZrO2.8Y2O3 added sequentially in increasing amounts until a thermal barrier coating is obtained. The enchanced thermal barrier coating has successfully passed 40 burner rig thermal shock cycles.

Space transportation booster engine configuration study. Addendum: Design definition document

NASA Technical Reports Server (NTRS)

1989-01-01

Gas generator engine characteristics and results of engine configuration refinements are discussed. Updated component mechanical design, performance, and manufacturing information is provided. The results are also provided of ocean recovery studies and various engine integration tasks. The details are provided of the maintenance plan for the Space Transportation Booster Engine.

Engine Power Turbine and Propulsion Pod Arrangement Study

NASA Technical Reports Server (NTRS)

Robuck, Mark; Zhang, Yiyi

2014-01-01

A study has been conducted for NASA Glenn Research Center under contract NNC10BA05B, Task NNC11TA80T to identify beneficial arrangements of the turboshaft engine, transmissions and related systems within the propulsion pod nacelle of NASA's Large Civil Tilt-Rotor 2nd iteration (LCTR2) vehicle. Propulsion pod layouts were used to investigate potential advantages, disadvantages, as well as constraints of various arrangements assuming front or aft shafted engines. Results from previous NASA LCTR2 propulsion system studies and tasks performed by Boeing under NASA contracts are used as the basis for this study. This configuration consists of two Fixed Geometry Variable Speed Power Turbine Engines and related drive and rotor systems (per nacelle) arranged in tilting nacelles near the wing tip. Entry-into-service (EIS) 2035 technology is assumed for both the engine and drive systems. The variable speed rotor system changes from 100 percent speed for hover to 54 percent speed for cruise by the means of a two speed gearbox concept developed under previous NASA contracts. Propulsion and drive system configurations that resulted in minimum vehicle gross weight were identified in previous work and used here. Results reported in this study illustrate that a forward shafted engine has a slight weight benefit over an aft shafted engine for the LCTR2 vehicle. Although the aft shafted engines provide a more controlled and centered CG (between hover and cruise), the length of the long rotor shaft and complicated engine exhaust arrangement outweighed the potential benefits. A Multi-Disciplinary Analysis and Optimization (MDAO) approach for transmission sizing was also explored for this study. This tool offers quick analysis of gear loads, bearing lives, efficiencies, etc., through use of commercially available RomaxDESIGNER software. The goal was to create quick methods to explore various concept models. The output results from RomaxDESIGNER have been successfully linked to Boeing

Additive Manufacture of Plasma Diagnostic Components Final Report Phase II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woodruff, Simon; Romero-Talamas, Carlos; You, Setthivoine

There is now a well-established set of plasma diagnostics (see e.g. [3]), but these remain some of the mostexpensive assemblies in fusion systems since for every system they have to be custom built, and time fordiagnostic development can pace the project. Additive manufacturing (AM) has the potential to decreaseproduction cost and significantly lower design time of fusion diagnostic subsystems, which would realizesignificant cost reduction for standard diagnostics. In some cases, these basic components can be additivelymanufactured for less than 1/100th costs of conventional manufacturing.In our DOE Phase II SBIR, we examined the impact that AM can have on plasma diagnosticmore » cost bytaking 15 separate diagnostics through an engineering design using Conventional Manufacturing (CM) tech-niques, then optimizing the design to exploit the benefits of AM. The impact of AM techniques on cost isfound to be in several areas. First, the cost of materials falls because AM parts can be manufactured withlittle to no waste, and engineered to use less material than CM. Next, the cost of fabrication falls for AMparts relative to CM since the fabrication time can be computed exactly, and often no post-processing isrequired for the part to be functional. We find that AM techniques are well suited for plasma diagnosticssince typical diagnostic complexity comes at no additional cost. Cooling channels, for example, can be builtin to plasma-facing components at no extra cost. Fabrication costs associated with assembly are lower forAM parts because many components can be combined and printed as monoliths, thereby mitigating the needfor alignment or calibration. Finally, the cost of engineering is impacted by exploiting AM design tools thatallow standard components to be customized through web-interfaces. Furthermore, we find that conceptdesign costs can be impacted by scripting interfaces for online engineering design tools.« less

Studies of dynamic processes related to active experiments in space plasmas

NASA Technical Reports Server (NTRS)

Banks, Peter M.; Neubert, Torsten

1992-01-01

This is the final report for grant NAGw-2055, 'Studies of Dynamic Processes Related to Active Experiments in Space Plasmas', covering research performed at the University of Michigan. The grant was awarded to study: (1) theoretical and data analysis of data from the CHARGE-2 rocket experiment (1keV; 1-46 mA electron beam ejections) and the Spacelab-2 shuttle experiment (1keV; 100 mA); (2) studies of the interaction of an electron beam, emitted from an ionospheric platform, with the ambient neutral atmosphere and plasma by means of a newly developed computer simulation model, relating model predictions with CHARGE-2 observations of return currents observed during electron beam emissions; and (3) development of a self-consistent model for the charge distribution on a moving conducting tether in a magnetized plasma and for the potential structure in the plasma surrounding the tether. Our main results include: (1) the computer code developed for the interaction of electrons beams with the neutral atmosphere and plasma is able to model observed return fluxes to the CHARGE-2 sounding rocket payload; and (2) a 3-D electromagnetic and relativistic particle simulation code was developed.

Studies of a plasma with a hot dense core in LAPD

NASA Astrophysics Data System (ADS)

van Compernolle, Bart; Gekelman, Walter; Pribyl, Patrick; Cooper, Chris

2009-11-01

Recently, considerable effort in the LArge Plasma Device at UCLA (LAPD) has gone into the study of large cathodes which would enable higher discharge currents and higher densities. The new cathode is made out of Lanthanum HexaBoride (LaB6). LaB6 has a low work function and has higher emissivity than Barium oxide coated cathodes. The operating temperature of LaB6 cathodes lies above 1600 degrees Celsius. Tests of this cathode in the Enormous Toroidal Plasma Device (ETPD) showed that densities in excess of 2 10^13 cm-3 and electron temperatures of 12 eV are feasible. Small LaB6 cathodes (3mm - 2cm) have been used before in LAPD in several experiments on heat transport and on magnetized flux ropes. The cathode presented in this paper has a 8 cm diameter, and can be positioned at different radial locations. The cathode will be pulsed into the standard background plasma (ne= 2 10^12 cm-3, .25 <=Te<=6 eV, dia = 60 cm, L = 18 m) creating a plasma with a hot dense core. We present the characterization of the core plasma at different conditions. Studies of the heat transport and density spreading at the interface between the core plasma and background plasma will be done by use of a variety of probes (Langmuir, magnetic, Mach, emissive) as well as fast photography.

Study of plasma adrenomedullin level in normal pregnancy and preclampsia.

PubMed

Senna, Azza Abo; Zedan, Magda; el-Salam, Gamal E Abd; el-Mashad, Ashraf I

2008-02-06

The aim of this study was to evaluate whether maternal circulating adrenomedullin (AM) values in patients with preeclampsia are different from those in normotensive pregnant women at different gestational ages. In a prospective clinical study, 90 women aged 17 to 40 years old, were divided into 4 main groups: group I (45 women): Normotensive pregnant women at first trimester (15 women), second trimester (15 women), and third trimester (15 women) of pregnancies. Group II (15 women): Pregnant women with preeclampsia at 25 to 38 weeks of gestation. Group III (15 women): Normotensive healthy nonpregnant women. Group IV (15 women): Hypertensive nonpregnant women. The plasma AM concentration was measured in all women by using enzyme immunoassay kits. Plasma AM levels in pregnant women with normal blood pressure at different gestational ages (first, second, and third trimesters) were statistically significantly higher than those detected in nonpregnant normotensive women and significantly increased with increasing gestational age (P < .001). Moreover, there was significant positive correlation between plasma AM levels and increasing gestational age (r = 0.915, P < .001). Preeclamptic patients had the highest mean plasma AM levels compared with all other groups, which is statistically significant (P < .001) and there was a significant positive correlation between plasma AM levels and systolic blood pressure, diastolic blood pressure, severity of preeclampsia, and proteinuria in pregnant patients with preeclampsia. Maternal plasma AM concentration increases throughout pregnancy and increases as gestational age progresses. AM production starts very early in gestation, suggesting that it may have an important role in human reproduction, from implantation to delivery. Maternal plasma AM level in preeclampsia appears to be higher than that in normal pregnancy.

Preliminary investigation on the use of low current pulsed power Z-pinch plasma devices for the study of early stage plasma instabilities

NASA Astrophysics Data System (ADS)

Kaselouris, E.; Dimitriou, V.; Fitilis, I.; Skoulakis, A.; Koundourakis, G.; Clark, E. L.; Chatzakis, J.; Bakarezos, Μ; Nikolos, I. K.; Papadogiannis, N. A.; Tatarakis, M.

2018-01-01

This article addresses key features for the implementation of low current pulsed power plasma devices for the study of matter dynamics from the solid to the plasma phase. The renewed interest in such low current plasma devices lies in the need to investigate methods for the mitigation of prompt seeding mechanisms for the generation of plasma instabilities. The low current when driven into thick wires (skin effect mode) allows for the simultaneous existence of all phases of matter from solid to plasma. Such studies are important for the concept of inertial confinement fusion where the mitigation of the instability seeding mechanisms arising from the very early moments within the target’s heating is of crucial importance. Similarly, in the magnetized liner inertial fusion concept it is an open question as to how much surface non-uniformity correlates with the magneto-Rayleigh-Taylor instability, which develops during the implosion. This study presents experimental and simulation results, which demonstrate that the use of low current pulsed power devices in conjunction with appropriate diagnostics can be important for studying seeding mechanisms for the imminent generation of plasma instabilities in future research.

Plasma Studies in the SPECTOR Experiment as Target Development for MTF

NASA Astrophysics Data System (ADS)

Ivanov, Russ; Young, William; the Fusion Team, General

2016-10-01

General Fusion (GF) is developing a Magnetized Target Fusion (MTF) concept in which magnetized plasmas are adiabatically compressed to fusion conditions by the collapse of a liquid metal vortex. To study and optimize the plasma compression process, GF has a field test program in which subscale plasma targets are rapidly compressed with a moving flux conserver. GF has done many field tests to date on plasmas with sufficient thermal confinement but with a compression geometry that is not nearly self-similar. GF has a new design for our subscale plasma injectors called SPECTOR (for SPhErical Compact TORoid) capable of generating and compressing plasmas with a more spherical form factor. SPECTOR forms spherical tokamak plasmas by coaxial helicity injection into a flux conserver (a = 9 cm, R = 19 cm) with a pre-existing toroidal field created by 0.5 MA current in an axial shaft. The toroidal plasma current of 100 - 300 kA resistively decays over a time period of 1.5 msec. SPECTOR1 has an extensive set of plasma diagnostics including Thomson scattering and polarimetry. MHD stability and lifetime of the plasma was explored in different magnetic configurations with a variable safety factor q(Ψ) . Relatively hot (Te >= 350 eV) and dense ( 1020 m-3) plasmas have achieved energy confinement times τE >= 100 μsec and are now ready for field compression tests. russ.ivanov@generalfusion.com.

The experiences of women engineers who have completed one to five years of professional engineering employment: A phenomenological study

NASA Astrophysics Data System (ADS)

White, Susan M.

Women engineers remain underrepresented in employment in engineering fields in the United States. Feminist theory views this gender disparity beyond equity in numbers for women engineers and looks at structural issues of women's access, opportunities, and quality of experience in the workplace. Research on women's success and persistence in engineering education is diverse; however, there are few studies that focus on the early years of women's careers in engineering and less using a phenomenological research design. Experiences of women engineers who have completed one to five years of professional engineering employment are presented using a phenomenological research design. Research questions explored the individual and composite experiences for the co-researchers of the study as well as challenges and advantages of the phenomenon of having completed one to five years of professional engineering employment. Themes that emanated from the data were a feeling that engineering is a positive profession, liking math and science from an early age, having experiences of attending math and science camps or learning and practicing engineering interests with their fathers for some co-researchers. Other themes included a feeling of being different as a woman in the engineering workplace, taking advantage of opportunities for training, education, and advancement to further their careers, and the role of informal and formal mentoring in developing workplace networks and engineering expertise. Co-researchers negotiated issues of management quality and support, experiences of gender discrimination in the workplace, and having to make decisions balancing their careers and family responsibilities. Finally, the women engineers for this research study expressed intentions to persist in their careers while pursuing expertise and experience in their individual engineering fields.

Charged Particle Environment Definition for NGST: L2 Plasma Environment Statistics

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Blackwell, William C.; Neergaard, Linda F.; Evans, Steven W.; Hardage, Donna M.; Owens, Jerry K.

2000-01-01

The plasma environment encountered by the Next Generation Space Telescope satellite in a halo orbit about L2 can include the Earth's magnetotail and magnetosheath in addition to the solar wind depending on the orbital radius chosen for the mission. Analysis of plasma environment impacts on the satellite requires knowledge of the average and extreme plasma characteristics to assess the magnitude of spacecraft charging and materials degradation expected for the mission lifetime. This report describes the analysis of plasma data from instruments onboard the IMP 8 and Geotail spacecraft used to produce the plasma database for the LRAD engineering-level phenomenology code developed to provide the NGST L2 environment definition.

Improvement in plasma illumination properties of ultrananocrystalline diamond films by grain boundary engineering

NASA Astrophysics Data System (ADS)

Sankaran, K. J.; Srinivasu, K.; Chen, H. C.; Dong, C. L.; Leou, K. C.; Lee, C. Y.; Tai, N. H.; Lin, I. N.

2013-08-01

Microstructural evolution of ultrananocrystalline diamond (UNCD) films as a function of substrate temperature (TS) and/or by introducing H2 in Ar/CH4 plasma is investigated. Variation of the sp2 and sp3 carbon content is analyzed using UV-Raman and near-edge X-ray absorption fine structure spectra. Morphological and microstructural studies confirm that films deposited using Ar/CH4 plasma at low TS consist of a random distribution of spherically shaped ultra-nano diamond grains with distinct sp2-bonded grain boundaries, which are attributed to the adherence of CH radicals to the nano-sized diamond clusters. By increasing TS, adhering efficiency of CH radicals to the diamond lattice drops and trans-polyacetylene (t-PA) encapsulating the nano-sized diamond grains break, whereas the addition of 1.5% H2 in Ar/CH4 plasma at low TS induces atomic hydrogen that preferentially etches out the t-PA attached to ultra-nano diamond grains. Both cases make the sp3-diamond phase less passivated. This leads to C2 radicals attaching to the diamond lattice promoting elongated clustered grains along with a complicated defect structure. Such a grain growth model is highly correlated to explain the technologically important functional property, namely, plasma illumination (PI) of UNCD films. Superior PI properties, viz. low threshold field of 0.21 V/μm with a high PI current density of 4.10 mA/cm2 (at an applied field of 0.25 V/μm) and high γ-coefficient (0.2604) are observed for the UNCD films possessing ultra-nano grains with a large fraction of grain boundary phases. The grain boundary component consists of a large amount of sp2-carbon phases that possibly form interconnected paths for facilitating the transport of electrons and the electron field emission process that markedly enhance PI properties.

Plasma Reforming And Partial Oxidation Of Hydrocarbon Fuel Vapor To Produce Synthesis Gas And/Or Hydrogen Gas

DOEpatents

Kong, Peter C.; Detering, Brent A.

2004-10-19

Methods and systems are disclosed for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

Plasma under control: Advanced solutions and perspectives for plasma flux management in material treatment and nanosynthesis

NASA Astrophysics Data System (ADS)

Baranov, O.; Bazaka, K.; Kersten, H.; Keidar, M.; Cvelbar, U.; Xu, S.; Levchenko, I.

2017-12-01

Given the vast number of strategies used to control the behavior of laboratory and industrially relevant plasmas for material processing and other state-of-the-art applications, a potential user may find themselves overwhelmed with the diversity of physical configurations used to generate and control plasmas. Apparently, a need for clearly defined, physics-based classification of the presently available spectrum of plasma technologies is pressing, and the critically summary of the individual advantages, unique benefits, and challenges against key application criteria is a vital prerequisite for the further progress. To facilitate selection of the technological solutions that provide the best match to the needs of the end user, this work systematically explores plasma setups, focusing on the most significant family of the processes—control of plasma fluxes—which determine the distribution and delivery of mass and energy to the surfaces of materials being processed and synthesized. A novel classification based on the incorporation of substrates into plasma-generating circuitry is also proposed and illustrated by its application to a wide variety of plasma reactors, where the effect of substrate incorporation on the plasma fluxes is emphasized. With the key process and material parameters, such as growth and modification rates, phase transitions, crystallinity, density of lattice defects, and others being linked to plasma and energy fluxes, this review offers direction to physicists, engineers, and materials scientists engaged in the design and development of instrumentation for plasma processing and diagnostics, where the selection of the correct tools is critical for the advancement of emerging and high-performance applications.

A 150 and 300 kW lightweight diesel aircraft engine design study

NASA Technical Reports Server (NTRS)

Brouwers, A. P.

1980-01-01

The diesel engine was reinvestigated as an aircraft powerplant through design study conducted to arrive at engine configurations and applicable advanced technologies. Two engines are discussed, a 300 kW six-cylinder engine for twin engine general aviation aircraft and a 150 kW four-cylinder engine for single engine aircraft. Descriptions of each engine include concept drawings, a performance analysis, stress and weight data, and a cost study. This information was used to develop two airplane concepts, a six-place twin and a four-place single engine aircraft. The aircraft study consists of installation drawings, computer generated performance data, aircraft operating costs, and drawings of the resulting airplanes. The performance data show a vast improvement over current gasoline-powered aircraft.

Study on plasma sheath and plasma transport properties in the azimuthator

NASA Astrophysics Data System (ADS)

Zhenyu, WANG; Binhao, JIANG; N, A. STROKIN; A, N. STUPIN

2018-04-01

A physical model of transport in an azimuthator channel with the sheath effect resulting from the interaction between the plasma and insulation wall is established in this paper. Particle in cell simulation is carried out by the model and results show that, besides the transport due to classical and Bohm diffusions, the sheath effect can significantly influences the transport in the channel. As a result, the ion density is larger than the electron density at the exit of azimuthator, and the non-neutral plasma jet is divergent, which is unfavorable for mass separation. Then, in order to improve performance of the azimuthator, a cathode is designed to emit electrons. Experiment results have demonstrated that the auxiliary cathode can obviously compensate the space charge in the plasma.

Numerical and experimental study on a pulsed-dc plasma jet

NASA Astrophysics Data System (ADS)

Liu, X. Y.; Pei, X. K.; Lu, X. P.; Liu, D. W.

2014-06-01

A numerical and experimental study of plasma jet propagation in a low-temperature, atmospheric-pressure, helium jet in ambient air is presented. A self-consistent, multi-species, two-dimensional axially symmetric plasma model with detailed finite-rate chemistry of helium-air mixture composition is used to provide insights into the propagation of the plasma jet. The obtained simulation results suggest that the sheath forms near the dielectric tube inner surface and shields the plasma channel from the tube surface. The strong electric field at the edge of the dielectric field enhances the ionization in the air mixing layer; therefore, the streamer head becomes ring-shaped when the streamer runs out of the tube. The avalanche-to-streamer transition is the main mechanism of streamer advancement. Penning ionization dominates the ionization reactions and increases the electrical conductivity of the plasma channel. The simulation results are supported by experimental observations under similar discharge conditions.

Security Quality Requirements Engineering (SQUARE): Case Study Phase III

DTIC Science & Technology

2006-05-01

Security Quality Requirements Engineering (SQUARE): Case Study Phase III Lydia Chung Frank Hung Eric Hough Don Ojoko-Adams Advisor...Engineering (SQUARE): Case Study Phase III CMU/SEI-2006-SR-003 Lydia Chung Frank Hung Eric Hough Don Ojoko-Adams Advisor Nancy R. Mead...1 1.1 The SQUARE Process ............................................................................... 1 1.2 Case Study Clients

Computational studies of an intake manifold for restricted engine application

NASA Astrophysics Data System (ADS)

Prasetyo, Bagus Dwi; Ubaidillah, Maharani, Elliza Tri; Setyohandoko, Gabriel; Idris, Muhammad Idzdihar

2018-02-01

The Formula Society of Automotive Engineer (FSAE) student competition is an international contest for a vehicle that entirely designed and built by students from various universities. The engine design in the Formula SAE competition has to comply a tight regulation. Concerning the engine intake line, an air restrictor of circular cross-section less than 20 mm must be fitted between the throttle valve and the engine inlet. The throat is aimed to limit the engine air flow rate as it strongly influences the volumetric efficiency and then the maximum power. This article focuses on the design of the engine intake system of the Bengawan FSAE team vehicle to optimize the engine power output and its stability. The performance of engine intake system is studied through computational fluid dynamics (CFD). The objective of CFD is to know the pressure, velocity, and airflow of the air intake manifold for the best performance of the engine. The three-dimensional drawing of the intake manifold was made, and CFD simulation was conducted using ANSYS FLUENT. Two models were studied. The result shows that the different design produces a different value of the velocity of airflow and the kind of flow type.

Study of an advanced General Aviation Turbine Engine (GATE)

NASA Technical Reports Server (NTRS)

Gill, J. C.; Short, F. R.; Staton, D. V.; Zolezzi, B. A.; Curry, C. E.; Orelup, M. J.; Vaught, J. M.; Humphrey, J. M.

1979-01-01

The best technology program for a small, economically viable gas turbine engine applicable to the general aviation helicopter and aircraft market for 1985-1990 was studied. Turboshaft and turboprop engines in the 112 to 746 kW (150 to 1000 hp) range and turbofan engines up to 6672 N (1500 lbf) thrust were considered. A good market for new turbine engines was predicted for 1988 providing aircraft are designed to capitalize on the advantages of the turbine engine. Parametric engine families were defined in terms of design and off-design performance, mass, and cost. These were evaluated in aircraft design missions selected to represent important market segments for fixed and rotary-wing applications. Payoff parameters influenced by engine cycle and configuration changes were aircraft gross mass, acquisition cost, total cost of ownership, and cash flow. Significant advantage over a current technology, small gas turbine engines was found especially in cost of ownership and fuel economy for airframes incorporating an air-cooled high-pressure ratio engine. A power class of 373 kW (500 hp) was recommended as the next frontier for technology advance where large improvements in fuel economy and engine mass appear possible through component research and development.

An experimental study of phase transitions in a complex plasma

NASA Astrophysics Data System (ADS)

Smith, Bernard Albert Thomas, II

In semiconductor manufacturing, contamination due to particulates significantly decreases the yield and quality of device fabrication, therefore increasing the cost of production. Dust particle clouds can be found in almost all plasma processing environments including both plasma etching devices and in plasma deposition processes. Dust particles suspended within such plasmas will acquire an electric charge from collisions with free electrons in the plasma. If the ratio of inter-particle potential energy to the average kinetic energy is sufficient, the particles will form either a "liquid" structure with short range ordering or a crystalline structure with long range ordering. Otherwise, the dust particle system will remain in a gaseous state. Many experiments have been conducted over the past decade on such complex plasmas to discover the character of the systems formed, but more work is needed to fully understand these structures. This paper describes the processes involved in setting up the CASPER GEC RF Reference Cell and the modifications necessary to examine complex plasmas. Research conducted to characterize the system is outlined to demonstrate that the CASPER Cell behaves as other GEC Cells. In addition, further research performed shows the behavior of the complex plasma system in the CASPER Cell is similar to complex plasmas studied by other groups in this field. Along the way analysis routines developed specifically for this system are described. New research involving polydisperse dust distributions is carried out in the system once the initial characterization is finished. Next, a system to externally vary the DC bias in the CASPER Cell is developed and characterized. Finally, new research conducted to specifically examine how the complex plasma system reacts to a variable DC bias is reported. Specifically, the response of the interparticle spacing to various system parameters (including the external DC bias) is examined. Also, a previously unreported

Fluid design studies of integrated modular engine system

NASA Technical Reports Server (NTRS)

Frankenfield, Bruce; Carek, Jerry

1993-01-01

A study was performed to develop a fluid system design and show the feasibility of constructing an integrated modular engine (IME) configuration, using an expander cycle engine. The primary design goal of the IME configuration was to improve the propulsion system reliability. The IME fluid system was designed as a single fault tolerant system, while minimizing the required fluid components. This study addresses the design of the high pressure manifolds, turbopumps and thrust chambers for the IME configuration. A physical layout drawing was made, which located each of the fluid system components, manifolds and thrust chambers. Finally, a comparison was made between the fluid system designs of an IME system and a non-network (clustered) engine system.

Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

NASA Astrophysics Data System (ADS)

Hamann, S.; Börner, K.; Burlacov, I.; Spies, H.-J.; Strämke, M.; Strämke, S.; Röpcke, J.

2015-12-01

A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

Study on Ferroelectric Thick Film Insulator Sleeve On Plasma Focus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sylvester, Gustavo; Silva, Patricio; Moreno, Jose

The effect of ferroelectric lead germanate Pb5Ge3O11 (PGO) thick film in the alumina insulator sleeve of the 400 Joule Mather-type plasma focus device, PF-400J is studied. The breakdown phase along the insulator is fundamental for the formation of a homogeneous and symmetric current sheath, that is essential for a good plasma pinching, high neutron yield and X-ray emissions. For over several hundreds of electrical discharges, the films show good mechanical and electric performance. From the beginning the operating system is highly reproducible, shot to shot, with a clear definition of the plasma pinch on the axis of discharge. The grademore » of influence of the electron emission from the ferroelectric is experimentally studied.« less

NASA Software Engineering Benchmarking Study

NASA Technical Reports Server (NTRS)

Rarick, Heather L.; Godfrey, Sara H.; Kelly, John C.; Crumbley, Robert T.; Wifl, Joel M.

2013-01-01

To identify best practices for the improvement of software engineering on projects, NASA's Offices of Chief Engineer (OCE) and Safety and Mission Assurance (OSMA) formed a team led by Heather Rarick and Sally Godfrey to conduct this benchmarking study. The primary goals of the study are to identify best practices that: Improve the management and technical development of software intensive systems; Have a track record of successful deployment by aerospace industries, universities [including research and development (R&D) laboratories], and defense services, as well as NASA's own component Centers; and Identify candidate solutions for NASA's software issues. Beginning in the late fall of 2010, focus topics were chosen and interview questions were developed, based on the NASA top software challenges. Between February 2011 and November 2011, the Benchmark Team interviewed a total of 18 organizations, consisting of five NASA Centers, five industry organizations, four defense services organizations, and four university or university R and D laboratory organizations. A software assurance representative also participated in each of the interviews to focus on assurance and software safety best practices. Interviewees provided a wealth of information on each topic area that included: software policy, software acquisition, software assurance, testing, training, maintaining rigor in small projects, metrics, and use of the Capability Maturity Model Integration (CMMI) framework, as well as a number of special topics that came up in the discussions. NASA's software engineering practices compared favorably with the external organizations in most benchmark areas, but in every topic, there were ways in which NASA could improve its practices. Compared to defense services organizations and some of the industry organizations, one of NASA's notable weaknesses involved communication with contractors regarding its policies and requirements for acquired software. One of NASA's strengths

Genetic studies of plasma analytes identify novel potential biomarkers for several complex traits

PubMed Central

Deming, Yuetiva; Xia, Jian; Cai, Yefei; Lord, Jenny; Del-Aguila, Jorge L.; Fernandez, Maria Victoria; Carrell, David; Black, Kathleen; Budde, John; Ma, ShengMei; Saef, Benjamin; Howells, Bill; Bertelsen, Sarah; Bailey, Matthew; Ridge, Perry G.; Hefti, Franz; Fillit, Howard; Zimmerman, Earl A.; Celmins, Dzintra; Brown, Alice D.; Carrillo, Maria; Fleisher, Adam; Reeder, Stephanie; Trncic, Nadira; Burke, Anna; Tariot, Pierre; Reiman, Eric M.; Chen, Kewei; Sabbagh, Marwan N.; Beiden, Christine M.; Jacobson, Sandra A.; Sirrel, Sherye A.; Doody, Rachelle S.; Villanueva-Meyer, Javier; Chowdhury, Munir; Rountree, Susan; Dang, Mimi; Kowall, Neil; Killiany, Ronald; Budson, Andrew E.; Norbash, Alexander; Johnson, Patricia Lynn; Green, Robert C.; Marshall, Gad; Johnson, Keith A.; Sperling, Reisa A.; Snyder, Peter; Salloway, Stephen; Malloy, Paul; Correia, Stephen; Bernick, Charles; Munic, Donna; Stern, Yaakov; Honig, Lawrence S.; Bell, Karen L.; Relkin, Norman; Chaing, Gloria; Ravdin, Lisa; Paul, Steven; Flashman, Laura A.; Seltzer, Marc; Hynes, Mary L.; Santulli, Robert B.; Bates, Vernice; Capote, Horacio; Rainka, Michelle; Friedl, Karl; Murali Doraiswamy, P.; Petrella, Jeffrey R.; Borges-Neto, Salvador; James, Olga; Wong, Terence; Coleman, Edward; Schwartz, Adam; Cellar, Janet S.; Levey, Allan L.; Lah, James J.; Behan, Kelly; Scott Turner, Raymond; Johnson, Kathleen; Reynolds, Brigid; Pearlson, Godfrey D.; Blank, Karen; Anderson, Karen; Obisesan, Thomas O.; Wolday, Saba; Allard, Joanne; Lerner, Alan; Ogrocki, Paula; Tatsuoka, Curtis; Fatica, Parianne; Farlow, Martin R.; Saykin, Andrew J.; Foroud, Tatiana M.; Shen, Li; Faber, Kelly; Kim, Sungeun; Nho, Kwangsik; Marie Hake, Ann; Matthews, Brandy R.; Brosch, Jared R.; Herring, Scott; Hunt, Cynthia; Albert, Marilyn; Onyike, Chiadi; D’Agostino, Daniel; Kielb, Stephanie; Graff-Radford, Neill R; Parfitt, Francine; Kendall, Tracy; Johnson, Heather; Petersen, Ronald; Jack, Clifford R.; Bernstein, Matthew; Borowski, Bret; Gunter, Jeff; Senjem, Matt; Vemuri, Prashanthi; Jones, David; Kantarci, Kejal; Ward, Chad; Mason, Sara S.; Albers, Colleen S.; Knopman, David; Johnson, Kris; Chertkow, Howard; Hosein, Chris; Mintzer, Jacob; Spicer, Kenneth; Bachman, David; Grossman, Hillel; Mitsis, Effie; Pomara, Nunzio; Hernando, Raymundo; Sarrael, Antero; Potter, William; Buckholtz, Neil; Hsiao, John; Kittur, Smita; Galvin, James E.; Cerbone, Brittany; Michel, Christina A.; Pogorelec, Dana M.; Rusinek, Henry; de Leon, Mony J; Glodzik, Lidia; De Santi, Susan; Johnson, Nancy; Chuang-Kuo; Kerwin, Diana; Bonakdarpour, Borna; Weintraub, Sandra; Grafman, Jordan; Lipowski, Kristine; Mesulam, Marek-Marsel; Scharre, Douglas W.; Kataki, Maria; Adeli, Anahita; Kaye, Jeffrey; Quinn, Joseph; Silbert, Lisa; Lind, Betty; Carter, Raina; Dolen, Sara; Borrie, Michael; Lee, T-Y; Bartha, Rob; Martinez, Walter; Villena, Teresa; Sadowsky, Carl; Khachaturian, Zaven; Ott, Brian R.; Querfurth, Henry; Tremont, Geoffrey; Frank, Richard; Fleischman, Debra; Arfanakis, Konstantinos; Shah, Raj C.; deToledo-Morrell, Leyla; Sorensen, Greg; Finger, Elizabeth; Pasternack, Stephen; Rachinsky, Irina; Drost, Dick; Rogers, John; Kertesz, Andrew; Furst, Ansgar J.; Chad, Stevan; Yesavage, Jerome; Taylor, Joy L.; Lane, Barton; Rosen, Allyson; Tinklenberg, Jared; Black, Sandra; Stefanovic, Bojana; Caldwell, Curtis; Robin Hsiung, Ging-Yuek; Mudge, Benita; Assaly, Michele; Fox, Nick; Schultz, Susan K.; Boles Ponto, Laura L.; Shim, Hyungsub; Ekstam Smith, Karen; Burns, Jeffrey M.; Swerdlow, Russell H.; Brooks, William M.; Marson, Daniel; Griffith, Randall; Clark, David; Geldmacher, David; Brockington, John; Roberson, Erik; Natelson Love, Marissa; DeCarli, Charles; Carmichael, Owen; Olichney, John; Maillard, Pauline; Fletcher, Evan; Nguyen, Dana; Preda, Andrian; Potkin, Steven; Mulnard, Ruth A.; Thai, Gaby; McAdams-Ortiz, Catherine; Landau, Susan; Jagust, William; Apostolova, Liana; Tingus, Kathleen; Woo, Ellen; Silverman, Daniel H.S.; Lu, Po H.; Bartzokis, George; Thompson, Paul; Donohue, Michael; Thomas, Ronald G.; Walter, Sarah; Gessert, Devon; Brewer, James; Vanderswag, Helen; Sather, Tamie; Jiminez, Gus; Balasubramanian, Archana B.; Mason, Jennifer; Sim, Iris; Aisen, Paul; Davis, Melissa; Morrison, Rosemary; Harvey, Danielle; Thal, Lean; Beckett, Laurel; Neylan, Thomas; Finley, Shannon; Weiner, Michael W.; Hayes, Jacqueline; Rosen, Howard J.; Miller, Bruce L.; Perry, David; Massoglia, Dino; Brawman-Mentzer, Olga; Schuff, Norbert; Smith, Charles D.; Hardy, Peter; Sinha, Partha; Oates, Elizabeth; Conrad, Gary; Koeppe, Robert A.; Lord, Joanne L.; Heidebrink, Judith L.; Arnold, Steven E.; Karlawish, Jason H.; Wolk, David; Clark, Christopher M.; Trojanowki, John Q.; Shaw, Leslie M.; Lee, Virginia; Korecka, Magdalena; Figurski, Michal; Toga, Arthur W.; Crawford, Karen; Neu, Scott; Schneider, Lon S.; Pawluczyk, Sonia; Beccera, Mauricio; Teodoro, Liberty; Spann, Bryan M.; Womack, Kyle; Mathews, Dana; Quiceno, Mary; Foster, Norm; Montine, Tom; Fruehling, J. Jay; Harding, Sandra; Johnson, Sterling; Asthana, Sanjay; Carlsson, Cynthia M.; Petrie, Eric C.; Peskind, Elaine; Li, Gail; Porsteinsson, Anton P.; Goldstein, Bonnie S.; Martin, Kim; Makino, Kelly M.; Ismail, M. Saleem; Brand, Connie; Smith, Amanda; Ashok Raj, Balebail; Fargher, Kristin; Kuller, Lew; Mathis, Chet; Ann Oakley, Mary; Lopez, Oscar L.; Simpson, Donna M.; Sink, Kaycee M.; Gordineer, Leslie; Williamson, Jeff D.; Garg, Pradeep; Watkins, Franklin; Cairns, Nigel J.; Raichle, Marc; Morris, John C.; Householder, Erin; Taylor-Reinwald, Lisa; Holtzman, David; Ances, Beau; Carroll, Maria; Creech, Mary L.; Franklin, Erin; Mintun, Mark A.; Schneider, Stacy; Oliver, Angela; Duara, Ranjan; Varon, Daniel; Greig, Maria T.; Roberts, Peggy; Varma, Pradeep; MacAvoy, Martha G.; Carson, Richard E.; van Dyck, Christopher H.; Davies, Peter; Holtzman, David; Morris, John C.; Bales, Kelly; Pickering, Eve H.; Lee, Jin-Moo; Heitsch, Laura; Kauwe, John; Goate, Alison; Piccio, Laura; Cruchaga, Carlos

2016-01-01

Genome-wide association studies of 146 plasma protein levels in 818 individuals revealed 56 genome-wide significant associations (28 novel) with 47 analytes. Loci associated with plasma levels of 39 proteins tested have been previously associated with various complex traits such as heart disease, inflammatory bowel disease, Type 2 diabetes, and multiple sclerosis. These data suggest that these plasma protein levels may constitute informative endophenotypes for these complex traits. We found three potential pleiotropic genes: ABO for plasma SELE and ACE levels, FUT2 for CA19-9 and CEA plasma levels, and APOE for ApoE and CRP levels. We also found multiple independent signals in loci associated with plasma levels of ApoH, CA19-9, FetuinA, IL6r, and LPa. Our study highlights the power of biological traits for genetic studies to identify genetic variants influencing clinically relevant traits, potential pleiotropic effects, and complex disease associations in the same locus.

Researching primary engineering education: UK perspectives, an exploratory study

NASA Astrophysics Data System (ADS)

Clark, Robin; Andrews, Jane

2010-10-01

This paper draws attention to the findings of an exploratory study that critically identified and analysed relevant perceptions of elementary level engineering education within the UK. Utilising an approach based upon grounded theory methodology, 30 participants including teachers, representatives of government bodies and non-profit providers of primary level engineering initiatives were interviewed. Three main concepts were identified during the analysis of findings, each relevant to primary engineering education. These were pedagogic issues, exposure to engineering within the curriculum and children's interest. The paper concludes that the opportunity to make a real difference to children's education by stimulating their engineering imagination suggests this subject area is of particular value.

An experimental study of icing control using DBD plasma actuator

NASA Astrophysics Data System (ADS)

Cai, Jinsheng; Tian, Yongqiang; Meng, Xuanshi; Han, Xuzhao; Zhang, Duo; Hu, Haiyang

2017-08-01

Ice accretion on aircraft or wind turbine has been widely recognized as a big safety threat in the past decades. This study aims to develop a new approach for icing control using an AC-DBD plasma actuator. The experiments of icing control (i.e., anti-/de-icing) on a cylinder model were conducted in an icing wind tunnel with controlled wind speed (i.e., 15 m/s) and temperature (i.e., -10°C). A digital camera was used to record the dynamic processes of plasma anti-icing and de-icing whilst an infrared imaging system was utilized to map the surface temperature variations during the anti-/de-icing processes. It was found that the AC-DBD plasma actuator is very effective in both anti-icing and de-icing operations. While no ice formation was observed when the plasma actuator served as an anti-icing device, a complete removal of the ice layer with a thickness of 5 mm was achieved by activating the plasma actuator for ˜150 s. Such information demonstrated the feasibility of plasma anti-/de-icing, which could potentially provide more effective and safer icing mitigation strategies.

Structures, performance, benefit, cost study. [gas turbine engines

NASA Technical Reports Server (NTRS)

Feder, E.

1981-01-01

Aircraft engine structures were studied to identify the advanced structural technologies that would provide the most benefits to future aircraft operations. A series of studies identified engine systems with the greatest potential for improvements. Based on these studies, six advanced generic structural concepts were selected and conceptually designed. The benefits of each concept were quantitatively assessed in terms of thrust specific fuel consumption, weight, cost, maintenance cost, fuel burned and direct operating cost plus interest. The probability of success of each concept was also determined. The concepts were ranked and the three most promising were selected for further study which consisted of identifying and comprehensively outlining the advanced technologies required to develop these concepts for aircraft engine application. Analytic, fabrication, and test technology developments are required. The technology programs outlined emphasize the need to provide basic, fundamental understanding of technology to obtain the benefit goals.

Fabrication of ceramic substrate-reinforced and free forms by mandrel plasma spraying metal-ceramic composites

NASA Technical Reports Server (NTRS)

Quentmeyer, R. J.; Mcdonald, G.; Hendricks, R. C.

1985-01-01

Components fabricated of, or coated with, ceramics have lower parasitic cooling requirements. Techniques are discussed for fabricating thin-shell ceramic components and ceramic coatings for applications in rocket or jet engine environments. Thin ceramic shells with complex geometric forms involving convolutions and reentrant surfaces were fabricated by mandrel removal. Mandrel removal was combined with electroplating or plasma spraying and isostatic pressing to form a metal support for the ceramic. Rocket engine thrust chambers coated with 0.08 mm (3 mil) of ZrO2-8Y2O3 had no failures and a tenfold increase in engine life. Some measured mechanical properties of the plasma-sprayed ceramic are presented.

Tissue-Engineering for the Study of Cardiac Biomechanics

PubMed Central

Ma, Stephen P.; Vunjak-Novakovic, Gordana

2016-01-01

The notion that both adaptive and maladaptive cardiac remodeling occurs in response to mechanical loading has informed recent progress in cardiac tissue engineering. Today, human cardiac tissues engineered in vitro offer complementary knowledge to that currently provided by animal models, with profound implications to personalized medicine. We review here recent advances in the understanding of the roles of mechanical signals in normal and pathological cardiac function, and their application in clinical translation of tissue engineering strategies to regenerative medicine and in vitro study of disease. PMID:26720588

Study of Plasma Adrenomedullin Level In Normal Pregnancy and Preclampsia

PubMed Central

Senna, Azza Abo; Zedan, Magda; Abd El Salam, Gamal E.; El Mashad, Ashraf I.

2008-01-01

Aim The aim of this study was to evaluate whether maternal circulating adrenomedullin (AM) values in patients with preeclampsia are different from those in normotensive pregnant women at different gestational ages. Subjects and Methods In a prospective clinical study, 90 women aged 17 to 40 years old, were divided into 4 main groups: group I (45 women): Normotensive pregnant women at first trimester (15 women), second trimester (15 women), and third trimester (15 women) of pregnancies. Group II (15 women): Pregnant women with preeclampsia at 25 to 38 weeks of gestation. Group III (15 women): Normotensive healthy nonpregnant women. Group IV (15 women): Hypertensive nonpregnant women. The plasma AM concentration was measured in all women by using enzyme immunoassay kits. Results Plasma AM levels in pregnant women with normal blood pressure at different gestational ages (first, second, and third trimesters) were statistically significantly higher than those detected in nonpregnant normotensive women and significantly increased with increasing gestational age (P < .001). Moreover, there was significant positive correlation between plasma AM levels and increasing gestational age (r = 0.915, P < .001). Preeclamptic patients had the highest mean plasma AM levels compared with all other groups, which is statistically significant (P < .001) and there was a significant positive correlation between plasma AM levels and systolic blood pressure, diastolic blood pressure, severity of preeclampsia, and proteinuria in pregnant patients with preeclampsia. Conclusion Maternal plasma AM concentration increases throughout pregnancy and increases as gestational age progresses. AM production starts very early in gestation, suggesting that it may have an important role in human reproduction, from implantation to delivery. Maternal plasma AM level in preeclampsia appears to be higher than that in normal pregnancy. PMID:18382699

Citation Analysis: A Case Study of Korean Scientists and Engineers in Electrical and Electronics Engineering.

ERIC Educational Resources Information Center

Rieh, Hae-young

1993-01-01

Describes a study that investigated the citation patterns of publications by scientists and engineers in electrical and electronics engineering in Korea. Citation behavior of personnel in government, universities, and industry is compared; and citation patterns from articles in Korean and non-Korean publications are contrasted. (Contains 27…

Computational study of sheath structure in oxygen containing plasmas at medium pressures

NASA Astrophysics Data System (ADS)

Hrach, Rudolf; Novak, Stanislav; Ibehej, Tomas; Hrachova, Vera

2016-09-01

Plasma mixtures containing active species are used in many plasma-assisted material treatment technologies. The analysis of such systems is rather difficult, as both physical and chemical processes affect plasma properties. A combination of experimental and computational approaches is the best suited, especially at higher pressures and/or in chemically active plasmas. The first part of our study of argon-oxygen mixtures was based on experimental results obtained in the positive column of DC glow discharge. The plasma was analysed by the macroscopic kinetic approach which is based on the set of chemical reactions in the discharge. The result of this model is a time evolution of the number densities of each species. In the second part of contribution the detailed analysis of processes taking place during the interaction of oxygen containing plasma with immersed substrates was performed, the results of the first model being the input parameters. The used method was the particle simulation technique applied to multicomponent plasma. The sheath structure and fluxes of charged particles to substrates were analysed in the dependence on plasma pressure, plasma composition and surface geometry.

Near Real Time Tools for ISS Plasma Science and Engineering Applications

NASA Astrophysics Data System (ADS)

Minow, J. I.; Willis, E. M.; Parker, L. N.; Shim, J.; Kuznetsova, M. M.; Pulkkinen, A. A.

2013-12-01

The International Space Station (ISS) program utilizes a plasma environment forecast for estimating electrical charging hazards for crews during extravehicular activity (EVA). The process uses ionospheric electron density and temperature measurements from the ISS Floating Potential Measurement Unit (FPMU) instrument suite with the assumption that the plasma conditions will remain constant for one to fourteen days with a low probability for a space weather event which would significantly change the environment before an EVA. FPMU data is typically not available during EVA's, therefore, the most recent FPMU data available for characterizing the state of the ionosphere during EVA is typically a day or two before the start of an EVA or after the EVA has been completed. In addition to EVA support, information on ionospheric plasma densities is often needed for support of ISS science payloads and anomaly investigations during periods when the FPMU is not operating. This presentation describes the application of space weather tools developed by MSFC using data from near real time satellite radio occultation and ground based ionosonde measurements of ionospheric electron density and a first principle ionosphere model providing electron density and temperature run in a real time mode by GSFC. These applications are used to characterize the space environment during EVA periods when FPMU data is not available, monitor for large charges in ionosphere density that could render the ionosphere forecast and plasma hazard assessment invalid, and validate the assumption of 'persistence of conditions' used in deriving the hazard forecast. In addition, the tools are used to provide space environment input to science payloads on ISS and anomaly investigations during periods the FPMU is not operating.

Basic Study on Engine with Scroll Compressor and Expander

NASA Astrophysics Data System (ADS)

Morishita, Etsuo; Kitora, Yoshihisa; Nishida, Mitsuhiro

Scroll compressors are becoming popular in air conditioning and refrigeration. This is primarily due to their higher efficiency and low noise/vibration characteristics. The scroll principle can be applied also to the steam expander and the Brayton cycle engine,as shown in the past literature. The Otto cycle spark-ignition engine with a scroll compressor and expander is studied in this report. The principle and basic structure of the scroll engine are explained,and the engine characteristic are calculated based on the idealized cycles and processes. A prototype model has been proposed and constructed. The rotary type engine has always had a problem with sealing. The scroll engine might overcome this shortcoming with its much lower rubbing speed compared to its previous counterparts,and is therefore worth investigating.

Initial Efforts in Characterizing Radiation and Plasma Effects on Space Assets: Bridging the Space Environment, Engineering and User Community

NASA Astrophysics Data System (ADS)

Zheng, Y.; Ganushkina, N. Y.; Guild, T. B.; Jiggens, P.; Jun, I.; Mazur, J. E.; Meier, M. M.; Minow, J. I.; Pitchford, D. A.; O'Brien, T. P., III; Shprits, Y.; Tobiska, W. K.; Xapsos, M.; Rastaetter, L.; Jordanova, V. K.; Kellerman, A. C.; Fok, M. C. H.

2017-12-01

The Community Coordinated Modeling Center (CCMC) has been leading the community-wide model validation projects for many years. Such effort has been broadened and extended via the newly-launched International Forum for Space Weather Modeling Capabilities Assessment (https://ccmc.gsfc.nasa.gov/assessment/), Its objective is to track space weather models' progress and performance over time, which is critically needed in space weather operations. The Radiation and Plasma Effects Working Team is working on one of the many focused evaluation topics and deals with five different subtopics: Surface Charging from 10s eV to 40 keV electrons, Internal Charging due to energetic electrons from hundreds keV to several MeVs. Single Event Effects from solar energetic particles (SEPs) and galactic cosmic rays (GCRs) (several MeV to TeVs), Total Dose due to accumulation of doses from electrons (>100 KeV) and protons (> 1 MeV) in a broad energy range, and Radiation Effects from SEPs and GCRs at aviation altitudes. A unique aspect of the Radiation and Plasma Effects focus area is that it bridges the space environments, engineering and user community. This presentation will summarize the working team's progress in metrics discussion/definition and the CCMC web interface/tools to facilitate the validation efforts. As an example, tools in the areas of surface charging/internal charging will be demoed.

Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study. Volume 3: Engine data summary

NASA Technical Reports Server (NTRS)

1981-01-01

The engine operating characteristics were examined. Inlet pressure effects, tank pressurization effects, steady-state specific impulse, and the steady-state cycle were studied. The propellant flow schematic and operating sequence are presented. Engine hardware drawings are included.

Life-Extending Control for Aircraft Engines Studied

NASA Technical Reports Server (NTRS)

Guo, Te-Huei

2002-01-01

Current aircraft engine controllers are designed and operated to provide both performance and stability margins. However, the standard method of operation results in significant wear and tear on the engine and negatively affects the on-wing life--the time between cycles when the engine must be physically removed from the aircraft for maintenance. The NASA Glenn Research Center and its industrial and academic partners have been working together toward a new control concept that will include engine life usage as part of the control function. The resulting controller will be able to significantly extend the engine's on-wing life with little or no impact on engine performance and operability. The new controller design will utilize damage models to estimate and mitigate the rate and overall accumulation of damage to critical engine parts. The control methods will also provide a means to assess tradeoffs between performance and structural durability on the basis of mission requirements and remaining engine life. Two life-extending control methodologies were studied to reduce the overall life-cycle cost of aircraft engines. The first methodology is to modify the baseline control logic to reduce the thermomechanical fatigue (TMF) damage of cooled stators during acceleration. To accomplish this, an innovative algorithm limits the low-speed rotor acceleration command when the engine has reached a threshold close to the requested thrust. This algorithm allows a significant reduction in TMF damage with only a very small increase in the rise time to reach the commanded rotor speed. The second methodology is to reduce stress rupture/creep damage to turbine blades and uncooled stators by incorporating an engine damage model into the flight mission. Overall operation cost is reduced by an optimization among the flight time, fuel consumption, and component damages. Recent efforts have focused on applying life-extending control technology to an existing commercial turbine engine

Study of Complex Plasmas with Magnetic Dipoles

DTIC Science & Technology

2017-10-10

variety of collective behavior manifested in a plasma, especially oscillations or waves characterized by high frequency accompanied by the motion of...behavior manifested in a plasma, especially oscillations or waves characterized by high frequency accompanied by the motion of electrons and/or ions...particles characterized by extremely low frequency modes and the collection of plasma particles characterized by high frequency modes. The interaction of

Diesel NO{sub x} reduction by plasma-regenerated absorbent beds

DOEpatents

Wallman, P.H.; Vogtlin, G.E.

1998-02-10

Reduction of NO{sub x} from diesel engine exhaust by use of plasma-regenerated absorbent beds is described. This involves a process for the reduction of NO{sub x} and particulates from diesel engines by first absorbing NO{sub x} onto a solid absorbent bed that simultaneously acts as a physical trap for the particulate matter, and second regenerating said solid absorbent by pulsed plasma decomposition of absorbed NO{sub x} followed by air oxidation of trapped particulate matter. The absorbent bed may utilize all metal oxides, but the capacity and the kinetics of absorption and desorption vary between different materials, and thus the composition of the absorbent bed is preferably a material which enables the combination of NO{sub x} absorption capability with catalytic activity for oxidation of hydrocarbons. Thus, naturally occurring or synthetically prepared materials may be utilized, particularly those having NO{sub x} absorption properties up to temperatures around 400 C which is in the area of diesel engine exhaust temperatures. 1 fig.

Diesel NO.sub.x reduction by plasma-regenerated absorbend beds

DOEpatents

Wallman, P. Henrik; Vogtlin, George E.

1998-01-01

Reduction of NO.sub.x from diesel engine exhaust by use of plasma-regenerated absorbent beds. This involves a process for the reduction of NO.sub.x and particulates from diesel engines by first absorbing NO.sub.x onto a solid absorbent bed that simultaneously acts as a physical trap for the particulate matter, and second regenerating said solid absorbent by pulsed plasma decomposition of absorbed NO.sub.x followed by air oxidation of trapped particulate matter. The absorbent bed may utilize all metal oxides, but the capacity and the kinetics of absorption and desorption vary between different materials, and thus the composition of the absorbent bed is preferably a material which enables the combination of NO.sub.x absorption capability with catalytic activity for oxidation of hydrocarbons. Thus, naturally occurring or synthetically prepared materials may be utilized, particularly those having NO.sub.x absorption properties up to temperatures around 400.degree. C. which is in the area of diesel engine exhaust temperatures.

A Sensitivity Study of Commercial Aircraft Engine Response for Emergency Situations

NASA Technical Reports Server (NTRS)

Csank, Jeffrey T.; May, Ryan D.; Litt, Jonathan S.; Guo, Ten-Huei

2011-01-01

This paper contains the details of a sensitivity study in which the variation in a commercial aircraft engine's outputs is observed for perturbations in its operating condition inputs or control parameters. This study seeks to determine the extent to which various controller limits can be modified to improve engine performance, while capturing the increased risk that results from the changes. In an emergency, the engine may be required to produce additional thrust, respond faster, or both, to improve the survivability of the aircraft. The objective of this paper is to propose changes to the engine controller and determine the costs and benefits of the additional capabilities produced by the engine. This study indicates that the aircraft engine is capable of producing additional thrust, but at the cost of an increased risk of an engine failure due to higher turbine temperatures and rotor speeds. The engine can also respond more quickly to transient commands, but this action reduces the remaining stall margin to possibly dangerous levels. To improve transient response in landing scenarios, a control mode known as High Speed Idle is proposed that increases the responsiveness of the engine and conserves stall margin

Studies on pressure-gain combustion engines

NASA Astrophysics Data System (ADS)

Matsutomi, Yu

Various aspects of the pressure-gain combustion engine are investigated analytically and experimentally in the current study. A lumped parameter model is developed to characterize the operation of a valveless pulse detonation engine. The model identified the function of flame quenching process through gas dynamic process. By adjusting fuel manifold pressure and geometries, the duration of the air buffer can be effectively varied. The parametric study with the lumped parameter model has shown that engine frequency of up to approximately 15 Hz is attainable. However, requirements for upstream air pressure increases significantly with higher engine frequency. The higher pressure requirement indicates pressure loss in the system and lower overall engine performance. The loss of performance due to the pressure loss is a critical issue for the integrated pressure-gain combustors. Two types of transitional methods are examined using entropy-based models. An accumulator based transition has obvious loss due to sudden area expansion, but it can be minimized by utilizing the gas dynamics in the combustion tube. An ejector type transition has potential to achieve performance beyond the limit specified by a single flow path Humphrey cycle. The performance of an ejector was discussed in terms of apparent entropy and mixed flow entropy. Through an ideal ejector, the apparent part of entropy increases due to the reduction in flow unsteadiness, but entropy of the mixed flow remains constant. The method is applied to a CFD simulation with a simple manifold for qualitative evaluation. The operation of the wave rotor constant volume combustion rig is experimentally examined. The rig has shown versatility of operation for wide range of conditions. Large pressure rise in the rotor channel and in a section of the exhaust duct are observed even with relatively large leakage gaps on the rotor. The simplified analysis indicated that inconsistent combustion is likely due to insufficient

Modular assembly of synthetic proteins that span the plasma membrane in mammalian cells.

PubMed

Qudrat, Anam; Truong, Kevin

2016-12-09

To achieve synthetic control over how a cell responds to other cells or the extracellular environment, it is important to reliably engineer proteins that can traffic and span the plasma membrane. Using a modular approach to assemble proteins, we identified the minimum necessary components required to engineer such membrane-spanning proteins with predictable orientation in mammalian cells. While a transmembrane domain (TM) fused to the N-terminus of a protein is sufficient to traffic it to the endoplasmic reticulum (ER), an additional signal peptidase cleavage site downstream of this TM enhanced sorting out of the ER. Next, a second TM in the synthetic protein helped anchor and accumulate the membrane-spanning protein on the plasma membrane. The orientation of the components of the synthetic protein were determined through measuring intracellular Ca 2+ signaling using the R-GECO biosensor and through measuring extracellular quenching of yellow fluorescent protein variants by saturating acidic and salt conditions. This work forms the basis of engineering novel proteins that span the plasma membrane to potentially control intracellular responses to extracellular conditions.

Study of unconventional aircraft engines designed for low energy consumption

NASA Technical Reports Server (NTRS)

Neitzel, R. E.; Hirschkron, R.; Johnston, R. P.

1976-01-01

A study of unconventional engine cycle concepts, which may offer significantly lower energy consumption than conventional subsonic transport turbofans, is described herein. A number of unconventional engine concepts were identified and parametrically studied to determine their relative fuel-saving potential. Based on results from these studies, regenerative, geared, and variable-boost turbofans, and combinations thereof, were selected along with advanced turboprop cycles for further evaluation and refinement. Preliminary aerodynamic and mechanical designs of these unconventional engine configurations were conducted and mission performance was compared to a conventional, direct-drive turofan reference engine. Consideration is given to the unconventional concepts, and their state of readiness for application. Areas of needed technology advancement are identified.

The deposition of thin titanium-nitrogen coatings on the surface of PCL-based scaffolds for vascular tissue engineering

NASA Astrophysics Data System (ADS)

Kudryavtseva, Valeriya; Stankevich, Ksenia; Kibler, Elina; Golovkin, Alexey; Mishanin, Alexander; Bolbasov, Evgeny; Choynzonov, Evgeny; Tverdokhlebov, Sergei

2018-04-01

Biodegradable polymer scaffolds for tissue engineering is a promising technology for therapies of patients suffering from the loss of tissue or its function including cardiac tissues. However, limitations such as hydrophobicity of polymers prevent cell attachment, cell conductivity, and endothelialization. Plasma modification of polymers allows producing materials for an impressive range of applications due to their unique properties. Here, we demonstrate the possibility of bioresorbable electrospun polycaprolacton (PCL) scaffold surface modification by reactive magnetron sputtering of the titanium target in a nitrogen atmosphere. The influence of the plasma treatment time on the structure and properties of electrospun PCL scaffolds was studied. We show that the plasma treatment does not change the physico-mechanical properties of electrospun PCL scaffolds, leads to an increase in PCL scaffold biocompatibility, and, simultaneously, increases their hydrophilicity. In conclusion, this modification method opens a route to producing scaffolds with enhanced biocompatibility for tissue engineered vascular grafts.

Hybrid vehicle system studies and optimized hydrogen engine design

NASA Astrophysics Data System (ADS)

Smith, J. R.; Aceves, S.

1995-04-01

We have done system studies of series hydrogen hybrid automobiles that approach the PNGV design goal of 34 km/liter (80 mpg), for 384 km (240 mi) and 608 km (380 mi) ranges. Our results indicate that such a vehicle appears feasible using an optimized hydrogen engine. We have evaluated the impact of various on-board storage options on fuel economy. Experiments in an available engine at the Sandia CRF demonstrated NO(x) emissions of 10 to 20 ppM at an equivalence ratio of 0.4, rising to about 500 ppm at 0.5 equivalence ratio using neat hydrogen. Hybrid simulation studies indicate that exhaust NO(x) concentrations must be less than 180 ppM to meet the 0.2 g/mile ULEV or Federal Tier II emissions regulations. LLNL has designed and fabricated a first generation optimized hydrogen engine head for use on an existing Onan engine. This head features 15:1 compression ratio, dual ignition, water cooling, two valves and open quiescent combustion chamber to minimize heat transfer losses. Initial testing shows promise of achieving an indicated efficiency of nearly 50% and emissions of less than 100 ppM NO(x). Hydrocarbons and CO are to be measured, but are expected to be very low since their only source is engine lubricating oil. A successful friction reduction program on the Onan engine should result in a brake thermal efficiency of about 42% compared to today's gasoline engines of 32%. Based on system studies requirements, the next generation engine will be about 2 liter displacement and is projected to achieve 46% brake thermal efficiency with outputs of 15 kW for cruise and 40 kW for hill climb.

A comparative study: Effect of plasma on V2O5 nanostructured thin films

NASA Astrophysics Data System (ADS)

Singh, Megha; Kumar, Prabhat; Sharma, Rabindar K.; Reddy, G. B.

2016-05-01

Vanadium pentoxide nanostructured thin films (NSTs) have been studied to analyze the effect of plasma on nanostructures grown and morphology of films deposited using sublimation process. Nanostructured thin films were deposited on glass substrates, one in presence of oxygen plasma and other in oxygen environment (absence of plasma). Films were characterized using XRD, Raman spectroscopy, SEM and HRTEM. XRD studies revealed α-V2O5 films (orthorhombic phase) with good crystallinity. However, film deposited in presence of plasma have higher peak intensities as compared to those deposited in absence of plasma. Raman studies also support these finding following same trends of considerable increase in intensity in case of film deposited in presence of plasma. SEM micrographs makes the difference more visible, as film deposited in plasma have well defined plate like structures whereas other film have not-clearly-defined petal-like structures. HRTEM results show orthorhombic phase with 0.39 nm interplanar spacing, as reported by XRD. Results are hereby in good agreement with each other.

Simulation Study of Structure and Properties of Plasma Liners for the PLX- α Project

NASA Astrophysics Data System (ADS)

Samulyak, Roman; Shih, Wen; Hsu, Scott; PLX-Alpha Team

2017-10-01

Detailed numerical studies of the propagation and merger of high-Mach-number plasma jets and the formation and implosion of plasma liners have been performed using the FronTier code in support of the Plasma Liner Experiment-ALPHA (PLX- α) project. Physics models include radiation, physical diffusion, plasma-EOS models, and an anisotropic diffusion model that mimics deviations from fully collisional hydrodynamics in outer layers of plasma jets. Detailed structure and non-uniformity of plasma liners of due to primary and secondary shock waves have been studies as well as averaged quantities of ram pressure and Mach number. Synthetic data from simulations have been compared with available experimental data from a multi-chord interferometer and survey and high-resolution spectrometers. Numerical studies of the sensitivity of liner properties to experimental errors in the initial masses of jets and the synchronization of plasma gun valves have also been performed. Supported by the ARPA-E ALPHA program.

X-ray free-electron laser studies of dense plasmas

NASA Astrophysics Data System (ADS)

Vinko, Sam M.

2015-10-01

> The high peak brightness of X-ray free-electron lasers (FELs), coupled with X-ray optics enabling the focusing of pulses down to sub-micron spot sizes, provides an attractive route to generating high energy-density systems on femtosecond time scales, via the isochoric heating of solid samples. Once created, the fundamental properties of these plasmas can be studied with unprecedented accuracy and control, providing essential experimental data needed to test and benchmark commonly used theoretical models and assumptions in the study of matter in extreme conditions, as well as to develop new predictive capabilities. Current advances in isochoric heating and spectroscopic plasma studies on X-ray FELs are reviewed and future research directions and opportunities discussed.

QSAT: The Satellite for Polar Plasma Observation

NASA Astrophysics Data System (ADS)

Tsuruda, Yoshihiro; Fujimoto, Akiko; Kurahara, Naomi; Hanada, Toshiya; Yumoto, Kiyohumi; Cho, Mengu

2009-04-01

This paper introduces QSAT, the satellite for polar plasma observation. The QSAT project began in 2006 as an initiative by graduate students of Kyushu University, and has the potential to contribute greatly to IHY (International Heliophysical Year) by showing to the world the beauty, importance, and relevance of space science. The primary objectives of the QSAT mission are (1) to investigate plasma physics in the Earth’s aurora zone in order to better understand spacecraft charging, and (2) to conduct a comparison of the field-aligned current observed in orbit with ground-based observations. The QSAT project can provide education and research opportunities for students in an activity combining space sciences and satellite engineering. The QSAT satellite is designed to be launched in a piggyback fashion with the Japanese launch vehicle H-IIA. The spacecraft bus is being developed at the Department of Aeronautics and Astronautics of Kyushu University with collaboration of Fukuoka Institute of Technology. Regarding the payload instruments, the Space Environment Research Center of Kyushu University is developing the magnetometers, whereas the Laboratory of Spacecraft Environment Interaction Engineering of Kyushu Institute of Technology is developing the plasma probes. We aim to be ready for launch in 2009 or later.

Maritime patrol aircraft engine study, General Electric Derivative Engines. Volume III. Appendix B: performance data, TF 34/T7 study AL turboprop. Final report October 1978-April 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirschkron, R.; Davis, R.H.; Warren, R.E.

1979-04-30

This study developed data on General Electric common core derivative engines for use in Maritime Patrol Aircraft (MPA) concept formulation studies. The study included the screening of potential General Electric turbofan and turboprop/turboshaft engines and the preparation of technical and planning information on three of the most promising engine candidates. Screening of General Electric derivative candidates was performed utilizing an analytical MPA model using synthesized mission profiles to rank the candidates in terms of fuel consumption, weight, cost and complexity. The three turboprop engines selected for further study were as follows: TF34 growth derivative version with boost and new LPTmore » (TF34/T7 Study A1), F404 derivative with booster stages and new LPT (F404/T1 Study A1), and GE27 scaled and boosted study engine (GE27/T3 Study A1). Volume I summarizes the screening analysis and contains technical, planning, installation, cost and development data for the three selected turboprop engines. Volumes II, III and IV of this report contain the detailed performance data estimates for the GE27/T3 Study A1, TF34/T7 Study A1 and F404/T1 Study A1 turboprop engines, respectively.« less

Study of Bird Ingestions into Small Inlet Area Aircraft Turbine Engines

DTIC Science & Technology

1990-12-01

engines (ALF502, TFE731 , TPE331, and JTI5D) included in the study. This includes 24 months of operations for the first three engines and 12 months of...through the National Teclical Bird Ingestion- TFE731 Information Service, Springfield, 4 Tuibine Engine,’ TPt331 Virginia 22161 Turbofan Engine...ALF502 Engine 7 2.2 Operations, TFE731 Engine 8 2.3 Operations, TPE331 Engine 9 3.1 Distribution of Bird Weights 13 3.2 Aircraft Ingestions by Month

Feedback control of plasma instabilities with charged particle beams and study of plasma turbulence

NASA Technical Reports Server (NTRS)

Tham, Philip Kin-Wah

1994-01-01

. A plasma instability is usually observed in its saturated state and appears as a single feature in the frequency spectrum with a single azimuthal and parallel wavenumbers. The physics of the non-zero spectral width was investigated in detail because the finite spectral width can cause "turbulent" transport. One aspect of the "turbulence" was investigated by obtaining the scaling of the linear growth rate of the instabilities with the fluctuation levels. The linear growth rates were measured with the established gated feedback technique. The research showed that the ExB instability evolves into a quasi-coherent state when the fluctuation level is high. The coherent aspects were studied with a bispectral analysis. Moreover, the single spectral feature was discovered to be actually composed of a few radial harmonics. The radial harmonics play a role in the nonlinear saturation of the instability via three-wave coupling.

Dusty Plasmas on the Lunar Surface

NASA Astrophysics Data System (ADS)

Horanyi, M.; Andersson, L.; Colwell, J.; Ergun, R.; Gruen, E.; McClintock, B.; Peterson, W. K.; Robertson, S.; Sternovsky, Z.; Wang, X.

2006-12-01

The electrostatic levitation and transport of lunar dust remains one of the most interesting and controversial science issues from the Apollo era. This issue is also of great engineering importance in designing human habitats and protecting optical and mechanical devices. As function of time and location, the lunar surface is exposed to solar wind plasma, UV radiation, and/or the plasma environment of our magnetosphere. Dust grains on the lunar surface collect an electrostatic charge; alter the large-scale surface charge density distribution, ?and subsequently develop an interface region to the background plasma and radiation. There are several in situ and remote sensing observations that indicate that dusty plasma processes are likely to be responsible for the mobilization and transport of lunar soil. These processes are relevant to: a) understanding the lunar surface environment; b) develop dust mitigation strategies; c) to understand the basic physical processes involved in the birth and collapse of dust loaded plasma sheaths. This talk will focus on the dusty plasma processes on the lunar surface. We will review the existing body of observations, and will also consider future opportunities for the combination of in situ and remote sensing observations. Our goals are to characterize: a) the temporal variation of the spatial and size distributions of the levitated/transported dust; and b) the surface plasma environment

Theoretical and experimental studies of space-related plasma wave propagation and resonance phenomena

NASA Technical Reports Server (NTRS)

Crawford, F. W.

1975-01-01

A ten year summary was given of university research on the nature and characteristics of space related plasma resonance phenomena, whistler propagation in laboratory plasmas, and theoretical and experimental studies of plasma wave propagation. Data are also given on long delayed echoes, low frequency instabilities, ionospheric heating, and backscatter, and pulse propagation. A list is included of all conference papers, publications, and reports resulting from the study.

A study of female students enrollment in engineering technology stem programs

NASA Astrophysics Data System (ADS)

Habib, Ihab S.

The problem studied in this research project was the enrollment of female STEM Engineering Technology students and the impact of professional mentoring and financial incentives on their enrollment, retention, and completion of engineering curriculum. Several tasks were presented in researchers' professional position; to recruit more students to the program, especially female as a minority in the Engineering Technology Department, make appropriate changes to the curriculum, and make improvements in mentoring students to improve rates of enrollment, retention, and completion of the program. A survey was created to study the effects of Science Engineering Technology and Mathematics for Engineering Technology (STEM ENGT) students' perceptions, mentorship, and scholarships availability, enrollment, retention, and program completion by enrolled student gender. Other studies have discovered that more scholarship and faculty mentorship support provided for female students resulted in improved diversity within engineering curricula student bodies (Sorcinelli, 2007).

Advanced General Aviation Turbine Engine (GATE) study

NASA Technical Reports Server (NTRS)

Smith, R.; Benstein, E. H.

1979-01-01

The small engine technology requirements suitable for general aviation service in the 1987 to 1988 time frame were defined. The market analysis showed potential United States engines sales of 31,500 per year providing that the turbine engine sales price approaches current reciprocating engine prices. An optimum engine design was prepared for four categories of fixed wing aircraft and for rotary wing applications. A common core approach was derived from the optimum engines that maximizes engine commonality over the power spectrum with a projected price competitive with reciprocating piston engines. The advanced technology features reduced engine cost, approximately 50 percent compared with current technology.

Basic Studies on High Pressure Air Plasmas

DTIC Science & Technology

2006-08-30

which must be added a 1.5 month salary to A. Bugayev for assistance in laser and optic techniques. 2 Part II Technical report Plasma-induced phase shift...two-wavelength heterodyne interferometry applied to atmospheric pressure air plasma 11.1 .A. Plasma-induced phase shift - Electron density...a driver, since the error on the frequency leads to an error on the phase shift. (c) Optical elements Mirrors Protected mirrors must be used to stand

Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamann, S., E-mail: hamann@inp-greifswald.de; Röpcke, J.; Börner, K.

2015-12-15

A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steelmore » samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH{sub 4}, C{sub 2}H{sub 2}, HCN, and NH{sub 3}). With the help of OES, the rotational temperature of the screen plasma could be determined.« less

Plasma Cell Cheilitis: A Clinicopathological and Immunohistochemical Study of 13 Cases

PubMed Central

Lee, Jin Yong; Kim, Kwang Ho; Hahm, Ji Eun; Ha, Jae Won; Kwon, Won Joo; Kim, Chul Woo

2017-01-01

Background Plasma cell cheilitis is an unusual benign plasma cell proliferative disease of an unknown etiology that typically presents on the lip. Objective The aim of this study was to investigate the clinicopathological characteristics of 13 cases of plasma cell cheilitis. Methods The present study investigated the clinical manifestations, treatment modalities, and outcome of 13 patients diagnosed with plasma cell cheilitis from 2011 to 2016 at Kangdong Sacred Heart Hospital and Hallym University Sacred Heart Hospital. Biopsy specimens of the all cases were evaluated using conventional hematoxylin and eosin staining with kappa and lambda immunoglobulin light chain immunohistochemistry. Results The age of the patients ranged from 39 to 86 years (mean, 64.7 years), with male predominance. Histopathologically, 61.5% and 38.5% of patients showed band-like and pan dermal plasmacytic infiltrates, respectively. Eosinophilic infiltration was noted in 69.2% of patients. All cases showed both kappa and lambda immunoglobulin light chain reactivities, and kappa predominance was confirmed in 9 patients (69.2%). A majority of the patients was treated with local therapy, such as intralesional steroid injection with topical tacrolimus. Among the 13 patients, plasma cell cheilitis completely resolved, partially resolved, and recurred in 3 (23.1%), 5 (38.5%), and 5 patients (38.5%), respectively. Conclusion Plasma cell cheilitis presented as erosive edematous circumscribed patches or plaques affecting mainly the lower lip of elderly male patients. The majority of histopathology cases showed characteristic plasma cell aggregation on the upper dermis that was immunopositive for immunoglobulin light chain, with kappa predominance. PMID:28966508

Oxygen Plasma Treatment on 3D-Printed Chitosan/Gelatin/Hydroxyapatite Scaffolds for Bone Tissue Engineering.

PubMed

Lee, Chang-Min; Yang, Seong-Won; Jung, Sang-Chul; Kim, Byung-Hoon

2017-04-01

The 3D hydroxyapatite/gelatin/chitosan composite scaffolds were fabricated by 3D printing technique. The scaffolds were treated by oxygen plasma to improve the bioactivity and its surface characterization and in vitro cell culture were investigated. The scaffolds exhibited the good porosity and interconnectivity of pores. After oxygen plasma etching, roughness and wettability on the scaffolds surface are increased. Plasma treated scaffolds showed higher proliferation than that of untreated scaffolds. Oxygen plasma treatment could be used as potential tool to enhance the biocompatibility on the 3D composite scaffolds.

Understanding women's choices to enroll in engineering: A case study

NASA Astrophysics Data System (ADS)

Young, Eileen

The underrepresentation of women in science, technology, engineering and mathematics (STEM) college programs is a troublesome local, national and global phenomenon. The topic of this doctoral thesis specifically focused on the underrepresentation of women in the field of engineering and more specifically on the factors that women may perceive as chiefly motivating them to choose engineering as a college major. By not choosing to major in engineering, women forego intellectual opportunities and the financial rewards that engineering careers can provide. Their absence means that the field of engineering also suffers from the lack of contributions from a diverse workforce. Women who graduated from a specific community college's engineering program in the United States were the focus of this qualitative study. Grounded in achievement motivation theory, and in particular expectancy-value theory of academic and career choice, this research was guided by two questions: How do women perceive their academic self-efficacies and expectations for success as influencing their decisions to enroll in engineering? How do women perceive their subjective task values as influencing their decisions to enroll in engineering? This single, holistic case study with one main unit of analysis incorporated a written questionnaire, individual interviews and a focus group meeting as the three instruments used to collect data. The qualitative data, cyclically coded, shed light on the complex mechanisms of academic and career choice.

TEBPP: Theoretical and Experimental study of Beam-Plasma-Physics

NASA Technical Reports Server (NTRS)

Anderson, H. R.; Bernstein, W.; Linson, L. M.; Papadopoulos, K.; Kellogg, P. J.; Szuszczewicz, E. P.; Hallinan, T. J.; Leinbach, H.

1980-01-01

The interaction of an electron beam (0 to 10 keV, 0 to 1.5 Amp) with the plasma and neutral atmospheres at 200 to 400 km altitude is studied with emphasis on applications to near Earth and cosmical plasmas. The interaction occurs in four space time regions: (1) near electron gun, beam coming into equilibrium with medium; (2) equilibrium propagation in ionosphere; (3) ahead of beam pulse, temporal and spatial precursors; (4) behind a beam pulse. While region 2 is of the greatest interest, it is essential to study Region 1 because it determines the characteristics of the beam as it enters 2 through 4.

Sensitivity of RF-driven Plasma Filaments to Trace Gases

NASA Astrophysics Data System (ADS)

Burin, M. J.; Czarnocki, C. J.; Czarnocki, K.; Zweben, S. J.; Zwicker, A.

2011-10-01

Filamentary structures have been observed in many types of plasma discharges in both natural (e.g. lightning) and industrial systems (e.g. dielectric barrier discharges). Recent progress has been made in characterizing these structures, though various aspects of their essential physics remain unclear. A common example of this phenomenon can be found within a toy plasma globe (or plasma ball), wherein a primarily neon gas mixture near atmospheric pressure clearly and aesthetically displays filamentation. Recent work has provided the first characterization of these plasma globe filaments [Campanell et al., Physics of Plasmas 2010], where it was noticed that discharges of pure gases tend not to produce filaments. We have extended this initial work to investigate in greater detail the dependence of trace gases on filamentation within a primarily Neon discharge. Our preliminary results using a custom globe apparatus will be presented, along with some discussion of voltage dependencies. Newly supported by the NSF/DOE Partnership in Basic Plasma Science and Engineering.

Effects of Shocks on Emission from Central Engines of Active Galactic Nuclei. I

NASA Technical Reports Server (NTRS)

Sivron, R.; Caditz, D.; Tsuruta, S.

1996-01-01

In this paper we show that perturbations of the accretion flow within the central engines of some active galactic nuclei (AGNS) are likely to form shock waves in the accreting plasma. Such shocks, which may be either collisional or collisionless, can contribute to the observed high-energy temporal and spectral variability. Our rationale is the following: Observations show that the continuum emission probably originates in an optically thin, hot plasma in the AGN central engine. The flux and spectrum from this hot plasma varies significantly over light crossing timescales. Several authors have suggested that macroscopic perturbations contained within this plasma are the sources of this variability. In order to produce the observed emission the perturbations must be radiatively coupled with the optically thin hot matter and must also move with high velocities. We suggest that shocks, which can be very effective in randomizing the bulk motion of the perturbations, are responsible for this coupling. Shocks should form in the central engine, because the temperatures and magnetic fields are probably reduced below their virial values by radiative dissipation. Perturbations moving at Keplerian speeds, or strong non-linear excitations, result in supersonic and super-Alfvenic velocities leading to shock waves within the hot plasma. We show that even a perturbation smaller than the emitting region can form a shock that significantly modifies the continuum emission in an AGN, and that the spectral and temporal variability from such a shock generally resembles those of radio-quiet AGNS. As an example, the shock inducing perturbation in our model is a small main-sequence star, the capturing and eventual accretion of which are known to be a plausible process. We argue that shocks in the central engine may also provide a natural triggering mechanism for the "cold" component of Guilbert & Rees two-phase medium and an efficient mecha- nism for angular momentum transfer. Current and

Inter-conversion of Work and Heat With Plasma Electric Fields

NASA Astrophysics Data System (ADS)

Avinash, K.

2010-11-01

Thermodynamics of a model system where a group of cold charged particles locally confined in a volume VP within a warm plasma of temperature T and fixed volume V (VP<plasma. Finally, the direct conversion of plasma heat into mechanical work is demonstrated via a Striling like engine cycle involving ES isothermal compression of plasma electric fields.

Study and development of acoustic treatment for jet engine tailpipes

NASA Technical Reports Server (NTRS)

Nelson, M. D.; Linscheid, L. L.; Dinwiddie, B. A., III; Hall, O. J., Jr.

1971-01-01

A study and development program was accomplished to attenuate turbine noise generated in the JT3D turbofan engine. Analytical studies were used to design an acoustic liner for the tailpipe. Engine ground tests defined the tailpipe environmental factors and laboratory tests were used to support the analytical studies. Furnace-brazed, stainless steel, perforated sheet acoustic liners were designed, fabricated, installed, and ground tested in the tailpipe of a JT3D engine. Test results showed the turbine tones were suppressed below the level of the jet exhaust for most far field polar angles.

Numerical study of the inductive plasma coupling to ramp up the plasma density for the Linac4 H- ion source

NASA Astrophysics Data System (ADS)

Ohta, M.; Mattei, S.; Yasumoto, M.; Hatayama, A.; Lettry, J.

2014-02-01

In the Linac4 H- ion source, the plasma is generated by an RF antenna operated at 2 MHz. In order to investigate the conditions necessary for ramping up the plasma density of the Linac4 H- ion source in the low plasma density, a numerical study has been performed for a wide range of parameter space of RF coil current and initial pressure from H2 gas injection. We have employed an Electromagnetic Particle in Cell model, in which the collision processes have been calculated by a Monte Carlo method. The results have shown that the range of initial gas pressure from 2 to 3 Pa is suitable for ramping up plasma density via inductive coupling.

TOPICAL REVIEW: Plasma assisted ignition and combustion

NASA Astrophysics Data System (ADS)

Starikovskaia, S. M.

2006-08-01

In recent decades particular interest in applications of nonequilibrium plasma for the problems of plasma-assisted ignition and plasma-assisted combustion has been observed. A great amount of experimental data has been accumulated during this period which provided the grounds for using low temperature plasma of nonequilibrium gas discharges for a number of applications at conditions of high speed flows and also at conditions similar to automotive engines. The paper is aimed at reviewing the data obtained and discusses their treatment. Basic possibilities of low temperature plasma to ignite gas mixtures are evaluated and historical references highlighting pioneering works in the area are presented. The first part of the review discusses plasmas applied to plasma-assisted ignition and combustion. The paper pays special attention to experimental and theoretical analysis of some plasma parameters, such as reduced electric field, electron density and energy branching for different gas discharges. Streamers, pulsed nanosecond discharges, dielectric barrier discharges, radio frequency discharges and atmospheric pressure glow discharges are considered. The second part depicts applications of discharges to reduce the ignition delay time of combustible mixtures, to ignite transonic and supersonic flows, to intensify ignition and to sustain combustion of lean mixtures. The results obtained by different authors are cited, and ways of numerical modelling are discussed. Finally, the paper draws some conclusions on the main achievements and prospects of future investigations in the field.

Layer-controllable graphene by plasma thinning and post-annealing

NASA Astrophysics Data System (ADS)

Zhang, Lufang; Feng, Shaopeng; Xiao, Shaoqing; Shen, Gang; Zhang, Xiumei; Nan, Haiyan; Gu, Xiaofeng; Ostrikov, Kostya (Ken)

2018-05-01

The electronic structure of graphene depends crucially on its layer number and therefore engineering the number of graphene's atomic stacking layers is of great importance for the preparation of graphene-based devices. In this paper, we demonstrated a relatively less invasive, high-throughput and uniform large-area plasma thinning of graphene based on direct bombardment effect of fast-moving ionic hydrogen or argon species. Any desired number of graphene layers including trilayer, bilayer and monolayer can be obtained. Structural changes of graphene layers are studied by optical microscopy, Raman spectroscopy and atomic force microscopy. Post annealing is adopted to self-heal the lattice defects induced by the ion bombardment effect. This plasma etching technique is efficient and compatible with semiconductor manufacturing processes, and may find important applications for graphene-based device fabrication.

7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 11 2014-01-01 2014-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of the...

7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 11 2012-01-01 2012-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of the...

7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 11 2010-01-01 2010-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of the...

7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 11 2013-01-01 2013-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of the...

7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.