1,721,126 research outputs found
Efficacy of narrow buffer strips in removing agricultural pollutants in the shallow subsurface water flux from a cultivated field in north-east Italy
No full textCompost utilization as nitrogen source on wheat (Triticum aestivum L.,) and sunflower (Helianthus annuus L.)
No full textUse of compost source for maze (Zea Mays): total biomass, grain yield and N efficiency evaluation.
No full textDe Neve S., Salomez J., Van Den Bosshe A., Haneklaus S., Van Cleemput O., Hofman G. and Schung E. (Eds.
Effects of different composts on soil nitrogen balance and dynamics in a biennial crop succession.
No full textWith the one exception of compost derived from food processing industry residues and municipal waste immediately after the first application, differences in N soil concentrations between compost treatments and control were always low, suggesting that, in general, composts released scarce amounts of nitrogen. In addition, no differences were detected among compost types even though they derived from materials of very different origin.
The rhythm of nitrogen release from compost appears to be of less importance given the weak rate of compost mineralization.
Crop response and N uptake were scarcely affected by compost fertilization, with little difference with respect to the unfertilized treatment. These data are in accordance with the literature, which reports values of available N, in the first year, of less than one fifth of the total N applied with compost. Hence, looking at the short-term, compost does not fulfil the N needs of crops under the pedo-climatic conditions of the experimental environment, so its use as unique source of N for crops is not recommendable. Nevertheless, these indications have to be considered transient, because they are relative to the first years of compost application. Indeed, according to the literature, an increment of both compost mineralization rate and crop recovery efficiency might be expected in the medium-long term. Moreover, the data highlighted the importance of compost in the integration of original N content of soil, with the purpose of maintaining the apparent N balance in equilibrium and avoiding a progressive depletion of the soil N
Effectiveness of different buffer strips in removing runoff pollutants from a cultivated field in North-East Italy
No full textLaser-Driven Neutron Generation with Near-Critical Targets and Application to Materials Characterization
Full text linkLaser-driven neutrons arouse outstanding interest because of their promising uses in several fields, from basic science to materials inspection. Many experiments achieved neutron yields [108 - 1010 n/(sr s)] suitable for applications. These results were obtained by exploiting high-energy (approximately 10-100 J) lasers working at low repetition rates. Instead, adopting advanced target configurations like near-critical double-layer targets (DLTs) and compact, commercial lasers was slightly considered. Here, a theoretical study is performed to address neutron generation with commercial (40-400 TW, 1-15 J) systems and DLTs. We investigate proton acceleration and interaction with various materials to induce (p, n) reactions. DLTs allow achieving 1-2 orders of magnitude larger neutron yields and maximum energies 3 times higher than with single-layer targets. Then, the feasibility of two materials characterization techniques, namely fast neutron activation analysis and pulsed fast neutron resonance radiography, is assessed. The results indicate that they can be performed with commercial lasers and DLTs
Analysis of high-frequency IGBT soft switching buck converter with saturable inductors
No full textIn this paper a high switching frequency buck converter using IGBTs is presented. This was done by using an auxiliary branch made of an IGBT of the same type as the one used for the main switch and saturable inductors. The proposed topology allows both switches to be fully soft switched to keep the efficiency high over a wide load range. Because of its topology the open loop behaviour of the converter can be unstable. A detailed small signal analysis is presented to explain this behaviour and as a basis for the synthesis of a closed loop controller. Experimental measurements on a laboratory prototype demonstrated the accuracy of the small signal analysis and validated the operation of the auxiliary network. The resulting efficiency is around 92% over a 200 to 800W output power range and at a 80kHz switching frequency
Performance of a constructed surface flow wetland in abating nutrients in agricultural drainage waters.
No full textSuperintense Laser-driven Ion Beam Analysis
Full text linkIon beam analysis techniques are among the most powerful tools for advanced materials characterization. Despite their growing relevance in a widening number of fields, most ion beam analysis facilities still rely on the oldest accelerator technologies, with severe limitations in terms of portability and flexibility. In this work we thoroughly address the potential of superintense laser-driven proton sources for this application. We develop a complete analytical and numerical framework suitable to describe laser-driven ion beam analysis, exemplifying the approach for Proton Induced X-ray/Gamma-ray emission, a technique of widespread interest. This allows us to propose a realistic design for a compact, versatile ion beam analysis facility based on this novel concept. These results can pave the way for ground-breaking developments in the field of hadron-based advanced materials characterization
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