2,475 research outputs found

    Synchronization of extended systems from internal coherence

    Full text link
    A condition for the synchronizability of a pair of PDE systems, coupled through a finite set of variables, is commonly the existence of internal synchronization or internal coherence in each system separately. The condition was previously illustrated in a forced-dissipative system, and is here extended to Hamiltonian systems, using an example from particle physics. Full synchronization is precluded by Liouville's theorem. A form of synchronization weaker than "measure synchronization" is manifest as the positional coincidence of coherent oscillations ("breathers" or "oscillons") in a pair of coupled scalar field models in an expanding universe with a nonlinear potential, and does not occur with a variant of the model that does not exhibit oscillons.Comment: version accepted for publication in PRE (paragraph beginning at the bottom of pg. 5 has been rewritten to suggest unifying principle for synchronizability, applying to both forced-dissipative and Hamiltonian systems; other minor changes

    Tuning phase-stability and short-range order through Al-doping in (CoCrFeMn)100-xAlx high entropy alloys

    Get PDF
    For (CoCrFeMn)100−x_{100-x}Alx_{x} high-entropy alloys, we investigate the phase evolution with increasing Al-content (0 ≤\le x ≤\le 20 at.%). From first-principles theory, the Al-doping drives the alloy structurally from FCC to BCC separated by a narrow two-phase region (FCC+BCC), which is well supported by our experiments. We highlight the effect of Al-doping on the formation enthalpy and electronic structure of (CoCrFeMn)100−x_{100-x}Alx_{x} alloys. As chemical short-range order (SRO) in multicomponent alloys indicates the nascent local order (and entropy changes), as well as expected low-temperature ordering behavior, we use thermodynamic linear-response within density-functional theory to predict SRO and ordering transformation and temperatures inherent in (CoCrFeMn)100−x_{100-x}Alx_{x}. The predictions agree with our present experimental findings, and other reported ones.Comment: 27 pages, 9 figures, 1 tabl

    Telemetry System Modifications and 1968-69 Operation

    Get PDF
    A discussion of telemetering system modifications is given, and discussion is presented of system operations for the 1968-69 snow season. A telemetering error analysis has been made for an operational period in February. A log is presented giving station operation periods, and a general summary of operational costs for the 1968-69 operational year is summarized

    From/To: Duane G. Rost (Chalk\u27s reply filed first)

    Get PDF

    Integrated Measurement of Soil Moisture by Use of Radio Waves

    Get PDF
    An integrated value of soil moisture can be determine dby measuring the attenuation of vertically-polarized surface radio waves taht are propagated over the ground between a transmitting and receiving atenna. Soil moisture values in the root-zone region were measured over longitudinal distances typically ranging from 50 feet to 600 feet with good results. Integrated soil moisture measurements over greater distances are also possible. Received field strength of propaged radio surface waves closely matches theoretical calculations. The measurement is easily made and does not disturb the soil. Dense, green vegetation, such as alfalfa or corn, causes errors in measurement accuracy. Less dense vegetation, such as range land, does not seriously affect measurement accuracy. The described equipment is portable and can be used by an unskilled operator

    Hydrologic Instrumentation and Telemetering

    Get PDF
    The following report discusses the various phases of work carried out by the Utah State University under a cooperative agreement contract with the Soil Conservation Service for the period extending from June 1965 to June1966. The body of the report discusses instrumentation techniques employed for the remote telemetering of total precipitation and water content of snow. Discussion of performance of a new type pressure pillow is also given for measuring the water content of snow. Data taken during system evaluation is presented in the Appendix

    Fourth Down and Ted

    Get PDF
    A review of John J. Miller\u27s The Big Scrum: How Teddy Roosevelt Saved Football
    • …
    corecore