681 research outputs found

    Automatic and frequency-programmable systems for feeding TMR: state of the art and available technologies

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    La tecnica di razionamento TMR (Total Mixed Ration) per bovine da latte si \ue8 molto diffusa grazie ai vantaggi offerti. La meccanizzazione si basa su carri miscelatori azionati da operatore. Alcuni limiti sono associabili alla bassa frequenza di distribuzione (1-2 volte/giorno). La recente diffusione di sistemi automatici per la preparazioone e distribuzione di TMR consente di introdurre inedite possibilit\ue0 di gestione dell'alimentazione. Circa 15 costruttori operanti su diversi concetti progettuali sono stati individuati. Tra le principali innovazioni vi \ue8 la possibilit\ue0 di variare la frequenza di distribuzione, modulare la razione, controllare gli orari di distribuzione, stimolare l'attivit\ue0 delle bovine, gestire l'ingestione di sostanza secca. Il lavoro presenta una panoramica sullo stato dell'arte della tecnologia e propone una classificazione dei robot per TMR

    Refurbishment of damaged tools using the combination of GTAW and laser beam welding

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    This paper presents the use of two welding processes for the refurbishment of damaged industrial tools. In the first part the problem is presented followed by the comparison of GTAW and laser welding in terms of repair welding of damaged tools. The macrosections of the welds show the difference between both welding processes in repairing of damaged tools. At the conclusion the main findings are presented. In many cases it is useful to use both welding processes in order to achieve better weld quality and to make welding more economical. The order of the technology used depends on the tool material, the use of the tool and the tool damage

    Refurbishment of damaged tools using the combination of GTAW and laser beam welding

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    This paper presents the use of two welding processes for the refurbishment of damaged industrial tools. In the first part the problem is presented followed by the comparison of GTAW and laser welding in terms of repair welding of damaged tools. The macrosections of the welds show the difference between both welding processes in repairing of damaged tools. At the conclusion the main findings are presented. In many cases it is useful to use both welding processes in order to achieve better weld quality and to make welding more economical. The order of the technology used depends on the tool material, the use of the tool and the tool damage

    Spatial periodic and homogeneous transverse stress loading on ITER TF Nb3Sn bronze and internal tin strand

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    The transport properties of the superconducting Nb3Sn layers in the strands strongly depend on the strain state. Knowledge of the influence of axial strain, periodic bending and contact stress on the critical current (Ic) of the used Nb3Sn strands is inevitable to gain sufficient confidence in an economic design and stable operation of ITER CICCs. In the past years we have measured the Ic and n-value of various ITER Nb3Sn strands with different layout in the TARSIS facility, when subjected to spatial periodic contact stress at a temperature of 4.2 K and in a magnet field of 12 T. Recently we have made the setup suitable for application of homogeneous load along the length of the wire (125 mm) in order to evaluate possible differences related to spatial stress and possible current distribution. We present an overview of the results obtained so far on an ITER TF bronze and internal tin strand.Comment: to be published in IEEE Trans Appl Supercon

    Information Flow through a Chaotic Channel: Prediction and Postdiction at Finite Resolution

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    We reconsider the persistence of information under the dynamics of the logistic map in order to discuss communication through a nonlinear channel where the sender can set the initial state of the system with finite resolution, and the recipient measures it with the same accuracy. We separate out the contributions of global phase space shrinkage and local phase space contraction and expansion to the uncertainty in predicting and postdicting the state of the system. Thus, we determine how the amplification parameter, the time lag, and the resolution influence the possibility for communication. A novel representation for real numbers is introduced that allows for a visualization of the flow of information between scales.Comment: 14 pages, 13 figure

    Proper ferroelastic phase transitions in thin epitaxial films with symmetry-conserving and symmetry-breaking misfit strains

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    We study how the ferroelastic domain structure sets in in an epitaxial film of a material with second order proper ferroelastic transition. The domain structures considered are similar to either a1/a2/a1/a2a_{1}/a_{2}/a_{1}/a_{2} or c/a/c/ac/a/c/a structures in perovskite ferroelectrics. If the "extrinsic" misfit strain, not associated with the transition, does not break the symmetry of the high-temperature phase, the phase transition in the film occurs at somewhat lower temperature compared to the bulk. The loss of stability then occurs with respect to a sinusoidal strain wave, which evolves into the domain structure with practically the same geometry and approximately the same period. In the presence of the symmetry-breaking component of the misfit strain ("extrinsic" misfit) the character of the phase transition is qualitatively different. In this case it is a {\em topological} transition between single-domain and multi-domain states, which starts from a low density of the domain walls.Comment: 7 pages, 2 figures, REVTeX 3.

    Geometry-dependent electrostatics near contact lines

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    Long-ranged electrostatic interactions in electrolytes modify their contact angles on charged substrates in a scale and geometry dependent manner. For angles measured at scales smaller than the typical Debye screening length, the wetting geometry near the contact line must be explicitly considered. Using variational and asymptotic methods, we derive new transcendental equations for the contact angle that depend on the electrostatic potential only at the three phase contact line. Analytic expressions are found in certain limits and compared with predictions for contact angles measured with lower resolution. An estimate for electrostatic contributions to {\it line} tension is also given.Comment: 3 .eps figures, 5p

    Land Suitability Evaluation of Abandoned Tin-mining Areas for Agricultural Development in Bangka Island, Indonesia

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    Kepulauan Bangka Belitung, Indonesia is one of the tin mineral-producer in the world. Agricultural crops could be a wise option for the reclamation since abandoned tin-mining lands have a high potency to be used as agricultural lands. This study was aimed to evaluate of the land/soil characteristics of abandoned tin-mining areas and to establish land suitability of the land area for agriculture used to formulate appropriate land development measures and amelioration strategies for utilization of mined areas for crop production. The land evaluation was conducted by comparing the land characteristics in every type of abandoned tin-mining areas with its crop requirements. The current suitability showed that in general food crops, vegetable crops, fruit crops, and industrial crops were consider as not suitable (N). Spice and medicinal crops [pepper (Piper nigrum L.) and citronella (Andropogoh nardus L. Rendle)] were consider as not suitable (N), while the Jatropha (Jatropha curcas L.) and Kemiri Sunan (Aleurites moluccana L. Willd) crops were considered as marginally suitable (S3) in abandoned tin-mining areas. The forest crops and forage crops were considered as marginally suitable (S3). The water availability, soil texture, and low soil fertility were considered as the limiting factors of all crops to get optimum production. For agricultural development, the soil physical and chemical properties of abandoned tin-mining land must be improved through integrated farming

    Alpha-foetoprotein and carcinoembryonic antigen in germ cell neoplasms.

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    Serum alpha-foetoprotein (AFP) and serum carcinoembryonic antigen (CEA) levels were measured, serially whenever possible, in 70 patients attending the Institute of Radiotherapy, Rotterdam, on account of testicular (65) or ovarian (4) germ cell tumours or, in one case, an endodermal sinus (yolk sac) tumour in the mediastinum. In 15 patients the disease was active; in the others it was in remission. Patients with active disease had raised serum AFP levels which correlated well with disease activity; no patient without evidence of active disease had raised serum AFP levels. None of the patients with active disease was found to have raised serum CEA levels. There was no correlation between serum AFP and CEA levels in patients with germ cell neoplasms, but good correlation between serum AFP levels and disease activity. Serum CEA levels did not correlate with disease activity, and serial determinations would therefore not be useful in monitoring progress in this group of diseases
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