36,296 research outputs found
Hydrogen-methane fuel control systems for turbojet engines
Design, development, and test of a fuel conditioning and control system utilizing liquid methane (natural gas) and liquid hydrogen fuels for operation of a J85 jet engine were performed. The experimental program evaluated the stability and response of an engine fuel control employing liquid pumping of cryogenic fuels, gasification of the fuels at supercritical pressure, and gaseous metering and control. Acceptably stable and responsive control of the engine was demonstrated throughout the sea level power range for liquid gas fuel and up to 88 percent engine speed using liquid hydrogen fuel
Energy Efficient Engine: Control system component performance report
An Energy Efficient Engine (E3) program was established to develop technology for improving the energy efficiency of future commercial transport aircraft engines. As part of this program, General Electric designed and tested a new engine. The design, fabrication, bench and engine testing of the Full Authority Digital Electronic Control (FADEC) system used for controlling the E3 Demonstrator Engine is described. The system design was based on many of the proven concepts and component designs used on the General Electric family of engines. One significant difference is the use of the FADEC in place of hydromechanical computation currently used
Entanglement entropy of multipartite pure states
Consider a system consisting of -dimensional quantum particles and
arbitrary pure state of the whole system. Suppose we simultaneously
perform complete von Neumann measurements on each particle. One can ask: what
is the minimal possible value of the entropy of outcomes joint
probability distribution? We show that coincides with entanglement
entropy for bipartite states. We compute for two sample multipartite
states: the hexacode state () and determinant states (). The
generalization of determinant states to the case is considered.Comment: 7 pages, REVTeX, corrected some typo
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Privatisation Methods and Economic Growth in Transition Economies
In low-income countries privatization, if implemented appropriately, may play an
important role in generating growth. Using data recently available from Central and
Eastern Europe, we therefore investigate the impact of alternative methods of
privatization on economic growth. Our analysis suggests that the use of conventional
privatization methods to match owners with firms can be inefficient in economies
with underdeveloped capital markets, particularly if wealth is poorly correlated with
managerial and entrepreneurial ability. In these circumstances mass privatization,
with firms being given away or sold at a nominal price, may be the appropriate policy
choice
Control means for a gas turbine engine
A means is provided for developing a signal representative of the actual compressor casing temperature, a second signal representative of compressor inlet gas temperature, and a third signal representative of compressor speed. Another means is provided for receiving the gas temperature and compressor speed signals and developing a schedule output signal which is a representative of a reference casing temperature at which a predetermined compressor blade stabilized clearance is provided. A means is also provided for comparing the actual compressor casing temperature signal and the reference casing temperature signal and developing a clearance control system representative of the difference. The clearance control signal is coupled to a control valve which controls a flow of air to the compressor casing to control the clearance between the compressor blades and the compressor casing. The clearance control signal can be modified to accommodate transient characteristics. Other embodiments are disclosed
Magnetoplasmadynamic thrustor research Final report
Radiation-cooled and water-cooled magnetoplasmadynamic thrustors tested in 10 to kW power range with 1000 to 5000 sec specific impuls
Combined inhibitory effect of nisin with EDTA against Listeria monocytogenes in soy-protein edible coating on turkey frankfurters stored at 4°C and 10°C
Several food contamination outbreaks are linked to Listeria monocytogenes. More effective methods are needed to prevent the growth and recontamination of L. monocytogenes on ready-to-eat (RTE) food products. Therefore, the objectives of this study were to evaluate the inhibitory activities of nisin (10,000 IU/mL), EDTA (sodium Ethylenediaminetetraacetic acid: 1.6 mg/mL), and the combination of nisin (10,000 IU/mL) with EDTA 1.6 mg/mL either in brain-heart-infusion (BHI) media at 37°C for 72 h or in soy-protein edible coating on the surface of full-fat commercial turkey frankfurters against the cell populations of approximately 106 colony forming units (CFU/mL) of L. monocytogenes. The surface-inoculated frankfurters were dipped into soy-protein film forming solutions with and without the addition of antimicrobial agents [(nisin (10,000 IU) or EDTA (0.16%) or the combination)] and stored at either 4°C or 10°C. The inhibitory effects of edible coatings were evaluated on a weekly basis for 45 d. The greatest inhibitory activities of 6 log cycle reductions of L. monocytogenes were found when nisin was combined with EDTA and eliminated 6 log cycles of L. monocytogenes in both systems. In the combined nisin (10,000 IU) with EDTA (0.16%) treatment, the L. monocytogenes population was reduced to undetectable levels after 15 h or 7 d incubation in BHI at 37°C or on turkey frankfurters stored at 4°C and 10°C, respectively. This research has demonstrated that the use of an edible film coating containing nisin with EDTA is a promising means of controlling the growth and recontamination of L. monocytogenes on RTE meat products
Detection of Multiparticle Entanglement: Quantifying the Search for Symmetric Extensions
We provide quantitative bounds on the characterisation of multiparticle
separable states by states that have locally symmetric extensions. The bounds
are derived from two-particle bounds and relate to recent studies on quantum
versions of de Finetti's theorem. We discuss algorithmic applications of our
results, in particular a quasipolynomial-time algorithm to decide whether a
multiparticle quantum state is separable or entangled (for constant number of
particles and constant error in the LOCC or Frobenius norm). Our results
provide a theoretical justification for the use of the Search for Symmetric
Extensions as a practical test for multiparticle entanglement.Comment: 5 pages, 1 figur
Hadronic light-by-light scattering contribution to the muon anomalous magnetic moment revisited
We discuss hadronic light-by-light scattering contribution to the muon
anomalous magnetic moment a_\mu^{\rm lbl}, paying particular attention to the
consistent matching between the short- and the long-distance behavior of the
light-by-light scattering amplitude. We argue that the short-distance QCD
imposes strong constraints on this amplitude overlooked in previous analyses.
We find that accounting for these constraints leads to approximately 50 per
cent increase in the central value of a_\mu^{\rm lbl}, compared to existing
estimates. The hadronic light-by-light scattering contribution becomes
a_\mu^{\rm lbl}=136(25) \times 10^{-11}, thereby shifting the Standard Model
prediction closer to the experimental value.Comment: 16 pages, 2 figure
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