1,398 research outputs found

    Grown organic matter as a fuel raw material resource

    Get PDF
    An extensive search was made on biomass production from the standpoint of climatic zones, water, nutrients, costs and energy requirements for many species. No exotic species were uncovered that gave hope for a bonanza of biomass production under culture, location, and management markedly different from those of existing agricultural concepts. A simulation analysis of biomass production was carried out for six species using conventional production methods, including their production costs and energy requirements. These estimates were compared with data on food, fiber, and feed production. The alternative possibility of using residues from food, feed, or lumber was evaluated. It was concluded that great doubt must be cast on the feasibility of producing grown organic matter for fuel, in competition with food, feed, or fiber. The feasibility of collecting residues may be nearer, but the competition for the residues for return to the soil or cellulosic production is formidable

    How the asymmetry of internal potential influences the shape of I-V characteristic of nanochannels

    Full text link
    Ion transport in biological and synthetic nanochannels is characterized by such phenomena as ion current fluctuations, rectification, and pumping. Recently, it has been shown that the nanofabricated synthetic pores could be considered as analogous to biological channels with respect to their transport characteristics \cite{Apel, Siwy}. The ion current rectification is analyzed. Ion transport through cylindrical nanopores is described by the Smoluchowski equation. The model is considering the symmetric nanopore with asymmetric charge distribution. In this model, the current rectification in asymmetrically charged nanochannels shows a diode-like shape of I−VI-V characteristic. It is shown that this feature may be induced by the coupling between the degree of asymmetry and the depth of internal electric potential well. The role of concentration gradient is discussed

    On the Accuracy of A.C. Flux Leakage, Eddy Current, EMAT and Ultrasonic Methods of Measuring Surface Connecting Flaws in Seamless Steel Tubing

    Get PDF
    The objective of this study was to perform a comparative experimental evaluation to determine the detection sensitivity, classification (fJaw type) and depth sizing accuracy of A.C. flux leakage, single-frequency eddy current, electromagnetic acoustic transducer (EMAT) generated surface waves, and broadband ultrasonic methods for the measurement of complex surface connecting flaws in hot rolled, seamless, ferritic tubing. Since it was of interest to invest NDE techniques over a wide range of capabilities, tubing having flaw depths far exceeding industry standards was tested and evaluated. Results of the study will be used to provide a benchmark assessment of these NDE methods, from which decisions concerning production test systems can be made

    Use of soil moisture information in yield models

    Get PDF
    There are no author-identified significant results in this report

    Generation of finite wave trains in excitable media

    Full text link
    Spatiotemporal control of excitable media is of paramount importance in the development of new applications, ranging from biology to physics. To this end we identify and describe a qualitative property of excitable media that enables us to generate a sequence of traveling pulses of any desired length, using a one-time initial stimulus. The wave trains are produced by a transient pacemaker generated by a one-time suitably tailored spatially localized finite amplitude stimulus, and belong to a family of fast pulse trains. A second family, of slow pulse trains, is also present. The latter are created through a clumping instability of a traveling wave state (in an excitable regime) and are inaccessible to single localized stimuli of the type we use. The results indicate that the presence of a large multiplicity of stable, accessible, multi-pulse states is a general property of simple models of excitable media.Comment: 6 pages, 6 figure
    • …
    corecore