989 resultados para echo chambers
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Soitinnus: orkesteri.
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The process of cold storage chambers contributes largely to the quality and longevity of stored products. In recent years, it has been intensified the study of control strategies in order to decrease the temperature change inside the storage chamber and to reduce the electric power consumption. This study has developed a system for data acquisition and process control, in LabVIEW language, to be applied in the cooling system of a refrigerating chamber of 30m³. The use of instrumentation and the application developed fostered the development of scientific experiments, which aimed to study the dynamic behavior of the refrigeration system, compare the performance of control strategies and the heat engine, even due to the controlled temperature, or to the electricity consumption. This system tested the strategies for on-off control, PID and fuzzy. Regarding power consumption, the fuzzy controller showed the best result, saving 10% when compared with other tested strategies.
Portable flow board for storage of fruits and vegetables in mini-chambers with controlled atmosphere
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ABSTRACT A portable flow board system was developed in the present study with the aim to facilitate lab-scale experiments of controlled atmosphere (CA) with fruits and vegetables. This sturdy flow board combines ease fabrication, low cost and gas economy. Its functionality is provided by manifolds and gas mixers. Each gaseous component is supplied by a gas cylinder through a differential valve of adjusted pressure control, generally at 6 kPa, and forced through 13 standardized restrictors coupled to each manifold output. Controlled atmospheres are then formed with one, two or three gases in 13 gas mixers affixed to the flow board base, which are further conducted through flexible tubes to storage mini-chambers that can also be used to study metabolic consumption and production of gaseous components. The restrictors used in the flow gaseous components were manufactured from microhematocrit test-type capillary glass tubes following the hot forming method under continuous air flow. The portable flow board showed to be low cost and simple post-harvest equipment that allows preparing controlled atmospheres in open systems with stable composition and flow, in a manner similar to traditional flow boards with control of gas escape by barostats.
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1912/06/16 (A1,N3).
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1913/02/02 (A2,N36).
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1894/07/22 (A1,N3).
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1912/10/06 (A1,N19).
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1895/09/15 (A2,N23).
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1912/09/01 (A1,N14).
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1912/08/11 (A1,N11).
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1912/09/08 (A1,N15).
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1912/12/08 (A1,N28).
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1912/12/29 (A1,N31).
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1913/07/20 (A3,N8).
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1912/08/18 (A1,N12).
