Supersonic fan blading

Radially extending rotor blades are disposed on a hub to form a supersonic propulsion fan for a turbofan engine. The peripheral spacing of the blades is such as to avoid forming a channel or passageway between adjacent blades. Each has a flat trailing surface extending from the leading edge at least as far to the rear as to cause any pressure waves which might originate on the blade surface to strike the leading surface of the following blade rather than propagate upstream of the blade row. The flat trailing surface of each blade makes an angle with the axis of rotation such that the blade is parallel to a gas inflow into the blades

On the Uniqueness of Quantum Equilibrium in Bohmian Mechanics

In Bohmian mechanics the distribution $|\psi|^2$ is regarded as the equilibrium distribution. We consider its uniqueness, finding that it is the unique equivariant distribution that is also a local functional of the wave function $\psi$.Comment: 15 pages, no figures, LaTe

VTOL and VSTOL handling qualities specifications, an overview of the current status

The highlights of a comparative analysis between the current helicopter and VSTOL specifications and four representative rotary wing aircraft are presented. Longitudinal, lateral, and directional control power and dynamic stability characteristics were analyzed for hovering conditions. Forward flight static and dynamic stability were analyzed for the longitudinal and lateral-directional axes. Results of the analyses in terms of the applicability/utility of the MIL-H-8501A criteria are presented for each of the above areas. The review of the MIL-H-8301A criteria against those in MIL-F-83300 and AGARD 577 indicate many areas in which MIL-H-8501A does not give adequate design guidance

Optical gyroscope system

Light beams pass in opposite directions through a single mode fiber optic wave guide that extends in a circle or coil in an optical gyroscope system which measures the rotation rate of the coil by measuring the relative phase shifts of the beams by interferometric techniques. Beam splitting and phase shifting of the light are facilitated by utilizing brief pulses of light and by using light-controlling devices which are operated for a brief time only when the light pulse passes in one direction through the device but not at a different time when the pulse is passing in the opposite direction through the device. High accuracy in rotation measurement is achieved at both very slow and very fast rotation rates, by alternately operating the system so that at zero rotation the interfering waves are alternately 90 out of phase and in phase. Linear polarization of the light beams is maintained by coiling the full length of the optic fiber in a single plane

Magnetohydrodynamic turbulence in the solar wind

Recent work in describing the solar wind as an MHD turbulent fluid has shown that the magnetic fluctuations are adequately described as time stationary and to some extent as spatially homogeneous. Spectra of the three rugged invariants of incompressible MHD are the principal quantities used to characterize the velocity and magnetic field fluctuations. Unresolved issues concerning the existence of actively developing turbulence are discussed

Disease-associated mutations in KCNE potassium channel subunits (MiRPs) reveal promiscuous disruption of multiple currents and conservation of mechanism.

KCNE genes encode single transmembrane-domain subunits, the MinK-related peptides (MiRPs), which assemble with pore-forming alpha subunits to establish the attributes of potassium channels in vivo. To investigate whether MinK, MiRP1, and MiRP2 operate similarly with their known native alpha subunit partners (KCNQ1, HERG, and Kv3.4, respectively) two conserved residues associated with human disease and influential in channel function were evaluated. As MiRPs assemble with a variety of alpha subunits in experimental cells and may do so in vivo, each peptide was also assessed with the other two alpha subunits. Inherited mutation of aspartate to asparagine (D --> N) to yield D76N-MinK is linked to cardiac arrhythmia and deafness; the analogs D82N-MiRP1 and D90N-MiRP2 were studied. Mutation of arginine to histidine (R --> H) to yield R83H-MiRP2 is associated with periodic paralysis; the analogs K69H-MinK and K75H-MiRP1 were also studied. Macroscopic and single-channel currents showed that D --> N mutations suppressed a subset of functions whereas R/K --> H changes altered the activity of MinK, MiRP1, and MiRP2 with all three alpha subunits. The findings indicate that the KCNE peptides interact similarly with different alpha subunits and suggest a hypothesis: that clinical manifestations of inherited KCNE point mutations result from disruption of multiple native currents via promiscuous interactions

Quasars as very-accurate clock synchronizers

Quasars can be employed to synchronize global data communications, geophysical measurements, and atomic clocks. It is potentially two to three orders of magnitude better than presently-used Moon-bounce system. Comparisons between quasar and clock pulses are used to develop correction or synchronization factors for station clocks

Formal Relationships: Introduction and Orientation

In 2009, Demographic Research will be publishing short reports on mathematical relationships in formal demography in a new Special Collection called "Formal Relationships". This first publication outlines the goals and procedures for publications in the collection. The guest editors of the collection are Joshua R. Goldstein and James W. Vaupel.

Acoustic properties of a supersonic fan

Acoustic properties of supersonic fan with short blade spa

Crosslinking and gelation between linear polymers: DNA-antibody complexes in systemic lupus erythematosus

In the autoimmune disease systemic lupus erythematosus the DNA molecules of an individual are attacked by its own antibodies. As these antibodies are bivalent they can crosslink different DNA molecules which can lead to the formation of DNA-antibody complexes and gels. Statistical properties of these complexes are derived and evaluated analytically in the limit of very long DNA molecules, as well as the concentrations at which a gel is being formed. The authors also present various numerical results for DNA molecules of intermediate lengths. This work can also be considered as a theory of the crosslinking and gelation of linear polymer