5,917 research outputs found
Investigations of lubricant rheology as applied to elastohydrodynamic lubrication
The pressure viscometer was modified to permit the measurement of viscosity at elevated pressures and shear stresses up to 5 x 10 to the 6th power N/sq m (720 psi). This shear stress is within a factor of three of the shear stress occurring in a sliding ehd point contact such as occurs in the ehd simulator. Viscosity data were taken on five lubricant samples, and it was found that viscous heating effects on the viscosity were predominant and not non-Newtonian behavior at the high shear stresses. The development of the infrared temperature measuring technique for the ehd simulator was completed, and temperature data for a set of operating conditions and one lubricant are reported. The numerical analysis of the behavior of nonlinear lubricants in the lubrication of rollers is reported
Linear-Time Zero-Knowledge Proofs for Arithmetic Circuit Satisfiability
We give computationally efficient zero-knowledge proofs of knowledge for arithmetic circuit satisfiability over a large field. For a circuit with N addition and multiplication gates, the prover only uses O(N)O(N) multiplications and the verifier only uses O(N)O(N) additions in the field. If the commitments we use are statistically binding, our zero-knowledge proofs have unconditional soundness, while if the commitments are statistically hiding we get computational soundness. Our zero-knowledge proofs also have sub-linear communication if the commitment scheme is compact.
Our construction proceeds in three steps. First, we give a zero-knowledge proof for arithmetic circuit satisfiability in an ideal linear commitment model where the prover may commit to secret vectors of field elements, and the verifier can receive certified linear combinations of those vectors. Second, we show that the ideal linear commitment proof can be instantiated using error-correcting codes and non-interactive commitments. Finally, by choosing efficient instantiations of the primitives we obtain linear-time zero-knowledge proofs
All-optical phase-regenerative multicasting of 40 Gbit/s DPSK signal in a degenerate phase sensitive amplifier
We demonstrate all-optical 1-to-5 differential phase-shift keyed (DPSK) wavelength multicasting at 40 Gbit/s using a degenerate four-wave mixing (FWM) based phase sensitive amplifier (PSA). Phase regenerative properties are reported with a sensitivity improvement of more that 10 dB
Saturation effects in degenerate phase sensitive fiber optic parametric amplifiers
We experimentally study saturation effects in degenerate phase sensitive amplifiers, revealing and explaining a gain regime suitable for all-optical signal processing functions such as phase regeneration
Identical temperature dependence of the time scales of several linear-response functions of two glass-forming liquids
The frequency-dependent dielectric constant, shear and adiabatic bulk moduli,
longitudinal thermal expansion coefficient, and longitudinal specific heat have
been measured for two van der Waals glass-forming liquids,
tetramethyl-tetraphenyl-trisiloxane (DC704) and 5-polyphenyl-4-ether. Within
the experimental uncertainties the loss-peak frequencies of the measured
response functions have identical temperature dependence over a range of
temperatures, for which the Maxwell relaxation time varies more than nine
orders of magnitude. The time scales are ordered from fastest to slowest as
follows: Shear modulus, adiabatic bulk modulus, dielectric constant,
longitudinal thermal expansion coefficient, longitudinal specific heat. The
ordering is discussed in light of the recent conjecture that van der Waals
liquids are strongly correlating, i.e., approximate single-parameter liquids.Comment: 8 pages, 6 figures, Substantially revised versio
All-optical phase and amplitude regeneration properties of a 40 Gbit/s DPSK black-box phase sensitive amplifier
We experimentally study the pure amplitude and phase regeneration capabilities of a blackbox degenerate four wave mixing (FWM) based bit-rate-flexible phase sensitive amplifier (PSA) for a 40 Gbit/s differential phase-shift keyed (DPSK) signal
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