832 research outputs found

    Stochastic thermodynamics of hidden pumps

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    We show that a reversible pumping mechanism operating between two states of a kinetic network can give rise to Poisson transitions between these two states. An external observer, for whom the pumping mechanism is not accessible, will observe a Markov chain satisfying local detailed balance with an emerging effective force induced by the hidden pump. Due to the reversibility of the pump, the actual entropy production turns out to be lower than the coarse grained entropy production estimated from the flows and affinities of the resulting Markov chain. Moreover, in presence of a large time scale separation between the fast pumping dynamics and the slow network dynamics, a finite current with zero dissipation may be produced. We make use of these general results to build a synthetase-like kinetic scheme able to reversibly produce high free energy molecules at a finite rate and a rotatory motor achieving 100\% efficiency at finite speed.Comment: 8 pages, 3 figures, v1: First version, v2: Major changes, new applications and new results (pumping can always be performed reversibly), v3 version accepted in Phys. Rev.

    Uncertainty, economic cycles and economic crises according to the continuism approach of Keynesian thought

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    Interpretando el pensamiento económico keynesiano según un planteamiento continuista entre el Tratado de la Moneda y la Teoría General, este artículo repasa el pensamiento postkeynesiano y estudia la influencia ejercida por los cambios en las economías occidentales a partir de los años de mil novecientos ochenta - como fueron los de la desregulación del mercado de trabajo, de la desregulación del mercado financiero y del fenómeno de las concentraciones empresariales –mediante proceso recesivo de la economía que llega a la crisis actual.This article revisits the post-Keynesian thought considering Keynes to have a continuism approach, that it to say, assuming that there is no break between A Treatise on Money and The General Theory. It studies the influence on economics of the changes which have taken place in Western economies from the 1980’s - the deregulation of the labor market, the deregulation of financial markets and the business concentration phenomenon – within the recessive process of the economy persisting in the current crisis

    The SPES project: a second generation ISOL facility

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    Abstract SPES is an INFN project to develop a Radioactive Ion Beam facility as an intermediate step toward EURISOL, the next generation European ISOL facility. The facility will be installed at the Laboratori Nazionali di Legnaro where the superconductive linac ALPI will reaccelerate the exotic beams at energies larger than 10 AMeV. Neutron-rich radioactive beams will be produced by proton-induced Uranium fission at an expected in-target fission rate of 1013 fissions per second. As proton driver, a 70 MeV cyclotron with a total current of 0.750 mA shared on two exit ports will be installed. The key feature of SPES is to provide high intensity and high-quality beams of neutron-rich nuclei to perform forefront research in nuclear physics as well as to develop and interdisciplinary research center based on the cyclotron proton beam. Neutron production at a rate of 1014 n/s is expected using the proton beam on thick target. The status of the project and the layout of the neutron facility will be presented. Two facilities can be operated at the same time, with a capability of 5000 h per year each. The ISOL facility will use 0.2 mA to reach the goal of 1013 fissions per second and more than 0.5 mA will be available for applied physics applications, mainly neutron beam and medical isotopes production

    Internal radiation dose assessment of radiopharmaceuticals prepared with cyclotron-produced 99m Tc

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    Technetium-99m (99m Tc) is the radioisotope most widely used in diagnostic nuclear medicine. It is readily available from 99 Mo/99m Tc generators as the \u3b2- decay product of the 99 Mo (T\ubd =66 h) parent nuclide. This latter is obtained as a fission product in nuclear reactors by neutron-induced reactions on highly enriched uranium. Alternative production routes, such as direct reactions using proton beams on specific target materials [100 Mo(p,2n)99m Tc], have the potential to be both reliable and relatively cost-effective. However, results showed that the 99m Tc extracted from proton-bombarded 100 Mo-enriched targets contains small quantities of several Tc radioisotopes (93m Tc, 93 Tc, 94 Tc, 94m Tc, 95 Tc, 95m Tc 96 Tc and 97m Tc). The aim of this work was to estimate the dose increase (DI) due to the contribution of Tc radioisotopes generated as impurities, after the intravenous injection of four radiopharmaceuticals prepared with cyclotron-produced 99m Tc (CP-99m Tc) using 99.05% 100 Mo-enriched metallic targets

    Thermalization induced by quantum scattering

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    We use quantum scattering theory to study a fixed quantum system Y subject to collisions with massive particles X described by wave-packets. We derive the scattering map for system Y and show that the induced evolution crucially depends on the width of the incident wave-packets compared to the level spacing in Y . If Y is non-degenerate, sequential collisions with narrow wave-packets cause Y to decohere. Moreover, an ensemble of narrow packets produced by thermal effusion causes Y to thermalize. On the other hand, broad wave-packets can act as a source of coherences for Y , even in the case of an ensemble of incident wave-packets given by the effusion distribution, preventing thermalization. We illustrate our findings on several simple examples and discuss the consequences of our results in realistic experimental situations

    Thermalization and dephasing in collisional reservoirs

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    We introduce a wide class of quantum maps that arise in collisional reservoirs and are able to thermalize a system if they operate in conjunction with an additional dephasing mechanism. These maps describe the effect of collisions and induce transitions between populations that obey detailed balance, but also create coherences that prevent the system from thermalizing. We combine these maps with a unitary evolution acting during random Poissonian times between collisions and causing dephasing. We find that, at a low collision rate, the nontrivial combination of these two effects causes thermalization in the system. This scenario is suitable for modeling collisional reservoirs at equilibrium. We justify this claim by identifying the conditions for such maps to arise within a scattering theory approach and provide a thorough characterization of the resulting thermalization process.Comment: 5 pages, 3 figure

    Zn-biofortification enhanced nitrogen metabolism and photorespiration process in green leafy vegetable Lactuca sativa L

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    Abstract BACKGROUND: Excessive rates of nitrogen (N) fertilizers may result in elevated concentrations of nitrate (NO3 −) in plants. Considering thatmany programs of biofortification with trace elements are being performed, it has become important to study how the application of these elements affects plant physiology and, particularly, N utilization in leaf crops. The main objective of the present study was to determine whether the NO3 − accumulation and the nitrogen use efficiency was affected by the application of different doses of Zn in Lactuca sativa plants. RESULTS: Zn doses in the range 80–100 mol L−1 produced an increase in Zn concentration provoking a decrease of NO3 − concentration and increase of the nitrate reductase, glutamine synthetase and aspartate aminotransferase activities, as well as the photorespiration processes. As result, we observed an increase in reduced N, total N concentration and N utilization efficiency. Consequently, at a dose of 80 mol L−1 of Zn, the amino acid concentration increased significantly. CONCLUSION: Adequate Zn fertilization is an important critical player in lettuce, especially at a dose of 80 mol L−1 of Zn, because it could result in an increase in the Zn concentration, a reduction of NO3 − levels and an increase the concentration of essential amino acids, with all of them having beneficial properties for the human diet

    Designing optimal discrete-feedback thermodynamic engines

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    Feedback can be utilized to convert information into useful work, making it an effective tool for increasing the performance of thermodynamic engines. Using feedback reversibility as a guiding principle, we devise a method for designing optimal feedback protocols for thermodynamic engines that extract all the information gained during feedback as work. Our method is based on the observation that in a feedback-reversible process the measurement and the time-reversal of the ensuing protocol both prepare the system in the same probabilistic state. We illustrate the utility of our method with two examples of the multi-particle Szilard engine.Comment: 15 pages, 5 figures, submitted to New J. Phy

    Tannin-modified soybean protein concentrate for wood adhesive

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    [EN] Soybean protein concentrate (SPC) modified with condensed mimosa tannin (CT) were employed as eco-friendly and formaldehyde-free adhesives for glued-wood joints. Eucalyptus grandis wood boards free of knots and cracks were used as substrate. Thermogravimetric analysis (TGA) showed that tannin provided higher thermal stability to the adhesive, which allowed expanding the temperature range for hot pressing. Apparent viscosity and dynamic angle contact were measured to evaluate the influence of tannin content on rheological behaviour and the wettability process. A classic shear-thinning behaviour was observed for all adhesives. Apparent viscosity and equilibrium contact angle reached a maximum value for low CT content. This effect was attributed to the existence of associative interactions between CT and SPC. Bonding quality parameters (wood failure percentage and shear strength) of the glued-wood joints were measured according to EN 302-1:2004 standard. 1 % CT w/w on SPC adhesive showed the best performance for dry conditions. These adhesives were suitable for glued-wood joints for indoor environments.This work was supported by the Agencia Nacional de promoción Científica y Tecnológica (ANPCyT) under Grant PICT 2016 0445; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Mar del Plata (UNMdP). A special thanks to Mr. Cesar Bovino (Aserradero Ubajay) for providing the wood.Esposito, L.; Ciannamea, EM.; Solaberrieta, I.; Piter, JC.; Ruseckaite, RA.; Stefani, PM. (2022). Tannin-modified soybean protein concentrate for wood adhesive. Journal of Applied Research in Technology & Engineering. 3(1):1-7. https://doi.org/10.4995/jarte.2022.15962OJS1731Aydin, I., & Colakoglu, G. (2007). 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Journal of the American Oil Chemists' Society, 89(9), 1733-1741. https://doi.org/10.1007/s11746-012-2058-2Ciannamea E M, Marin D C, Ruseckaite R A and Stefani P M (2017) Particleboard based on rice husk: effect of binder content and processing conditions J. Renew. Mater 5 19-22. https://doi.org/10.7569/JRM.2017.634125Chalapud, M. C.; Herdt, M.; Nicolao, E. S.; Ruseckaite, R. A.; Ciannamea, E. M.; Stefani, P. M. (2020). Biobased particleboards based on rice husk and soy proteins: Effect of the impregnation with tung oil on the physical and mechanical behavior. Constr Build Mater. 230: 116996. https://doi.org/10.1016/j.conbuildmat.2019.116996Damodaran, S.; Zhu, D. (2016) A formaldehyde-free water-resistant soy flour-based adhesive for plywood. J. Am. Oil. Chem. Soc. 93, 1311-1318. https://doi.org/10.1007/s11746-016-2866-xde Freitas, V., & Mateus, N. (2012). Protein/polyphenol interactions: past and present contributions. Mechanisms of astringency perception. Current Organic Chemistry, 16(6), 724-746. https://doi.org/10.2174/138527212799958002FAO (2019) http://www.fao.org/faostat/es/#data/QCGhahri, S., Pizzi, A., Mohebby, B., Mirshokraie, A., & Mansouri, H. R. (2017). Soy-based, tannin-modified plywood adhesives. The Journal of Adhesion, 94(3), 218-237. https://doi.org/10.1080/00218464.2016.1258310Ghahri, S., Pizzi, A., Mohebby, B., Mirshoktaie, A., Mansouri, H. R. (2018). Improving water resistance of soy-based adhesive by vegetable tannin. Journal of Polymers and the Environment, 26(5), 1881-1890. https://doi.org/10.1007/s10924-017-1090-6Ghahri, S.; Chen, X.; Pizzi,A.; Hajihassani, R.; Papadopoulos (2021) A.N. Natural Tannins as New Cross-Linking Materials for Soy-Based Adhesives. Polymers, 13, 595. https://doi.org/10.3390/polym13040595Hagenimana, A.; Ding X.; Gu W.Y. (2007), Steady state flow behaviors of extruded blend of rice flour and soy protein concentrate, Food Chemistry, 101, 241 - 247. https://doi.org/10.1016/j.foodchem.2006.01.043Hojilla-Evangelista, M. P. (2010). Adhesion properties of plywood glue containing soybean meal as an extender. Journal of the American Oil Chemists' Society, 87(9), 1047-1052. https://doi.org/10.1007/s11746-010-1586-xHunt, C. G.; Frihart, C. R.; Dunky, M.; Rohumaa, A. (2018). Understanding wood bonds-going beyond what meets the eye: a critical review. Reviews of Adhesion and Adhesives, 6(4), 369-440. https://doi.org/10.7569/RAA.2018.097312Jang, Y., Li, K. (2015). An All-Natural Adhesive for Bonding Wood. Journal of the American Oil Chemists' Society, 92(3), 431-438. https://doi.org/10.1007/s11746-015-2610-yKhosravi, S., Nordqvist, P., Khabbaz, F., Öhman, C., Bjurhager, I., & Johansson, M. (2015). Wetting and film formation of wheat gluten dispersions applied to wood substrates as particle board adhesives. 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    Upgrade of the HIVIPP Deposition Apparatus for Nuclear Physics Thin Targets Manufacturing

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    The High Energy Vibrational Powder Plating (HIVIPP) technique allows for the preparation of targets starting from refractory metal powders with negligible material losses during the process, thus preserving the expensive isotope-enriched materials. An upgraded HIVIPP apparatus was developed at the Legnaro National Laboratory of the National Institute of Nuclear Physics (INFN-LNL), and it is reported in this work. Particular attention was paid to the design of the sample holder, the automation of the power supply, and the control of the process, all with the aim of obtaining a versatile and reliable apparatus. Several tests have been carried out and the related results are reported proving the flexibility of the apparatus and the process reproducibility. The main result is a 'ready to use' technology at INFN-LNL for the preparation of isotopically enriched refractory metal targets that cannot be manufactured using standard techniques
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