Collective excitations in 2D hard-disc fluid.

Collective dynamics of a two-dimensional (2D) hard-disc fluid was studied by molecular dynamics simulations in the range of packing fractions that covers states up to the freezing. Some striking features concerning collective excitations in this system were observed. In particular, the short-wavelength shear waves while being absent at low packing fractions were observed in the range of high packing fractions, just before the freezing transition in a 2D hard-disc fluid. In contrast, the so-called "positive sound dispersion" typically observed in dense Lennard-Jones-like fluids, was not detected for the 2D hard-disc fluid. The ratio of specific heats in the 2D hard-disc fluid shows a monotonic increase with density approaching the freezing, resembling in this way the similar behavior in the vicinity of the Widom line in the case of supercritical fluids.

Storage of Elmwood kiwifruit in controlled atmosphere and ethylene management / Armazenamento de kiwi cv. Elmwood em atmosfera controlada e manejo do etileno

The aim of this work was to evaluate Elmwood kiwifruit conservation under different controlled atmosphere (CA) conditions, with or without ethylene absorption and inhibition of ethylene action by 1-MCP. The treatments were: [1] cold storage (CS), [2] CA with 1.5 kPa O2 and 5.0 kPa CO2 plus ethylene scrubbing , [3] CA with 2.0 kPa O2 and 5.0 kPa CO2 plus ethylene scrubbing [4] CA with 2.0 kPa O2 and 5.0 kPa CO2 without ethylene scrubbing and [5] CA with 2.0 kPa O2 and 7.0 kPa CO2 plus ethylene scrubbing. Fruits from all treatments were stored for fi ve months at -0.5ºC, with and without 1.0 ppm of 1-metylcyclopropene (1-MCP). 1-MCP application, on this study, provided an uneven ripening in fruits stored in CA, with more pronounced softening of the pulp in relation to the core. The three CA conditions showed a similar effect on the kiwifruit conservation and the ethylene scrubbing delayed ripening of the fruits during storage and shelf life.

O objetivo deste trabalho foi avaliar a conservação de kiwi Elmwood em função das condições de atmosfera controlada (AC), absorção de etileno e aplicação de 1-MCP. Os tratamentos foram: [1] armazenamento refrigerado (AR), [2] AC com 1,5 kPa O2 e 5,0 kPa CO2 com absorção de etileno, [3] AC com 2,0 kPa O2 e 5,0 kPa CO2 com absorção de etileno [4] AC com 2,0 kPa O2 e 5,0 kPa CO2 , [5] AC com 2,0 kPa O2 e 7,0 kPa CO2 com absorção de etileno. Os frutos de todos os tratamentos permaneceram armazenados durante cinco meses na temperatura de -0,5ºC, com e sem aplicação de 1,0 ppm de 1-metilciclopropeno (1-MCP). A aplicação de 1-MCP, neste trabalho, proporcionou um amadurecimento desuniforme nos frutos armazenados em AC, com o amolecimento mais pronunciado da polpa em relação à columela. As três condições de AC apresentaram um efeito semelhante na conservação do kiwi e a absorção de etileno retardou o amadurecimento durante o armazenamento e na vida de prateleira.

Storage of Elmwood kiwifruit in controlled atmosphere and ethylene management / Armazenamento de kiwi cv. Elmwood em atmosfera controlada e manejo do etileno

The aim of this work was to evaluate Elmwood kiwifruit conservation under different controlled atmosphere (CA) conditions, with or without ethylene absorption and inhibition of ethylene action by 1-MCP. The treatments were: [1] cold storage (CS), [2] CA with 1.5 kPa O2 and 5.0 kPa CO2 plus ethylene scrubbing , [3] CA with 2.0 kPa O2 and 5.0 kPa CO2 plus ethylene scrubbing [4] CA with 2.0 kPa O2 and 5.0 kPa CO2 without ethylene scrubbing and [5] CA with 2.0 kPa O2 and 7.0 kPa CO2 plus ethylene scrubbing. Fruits from all treatments were stored for fi ve months at -0.5ºC, with and without 1.0 ppm of 1-metylcyclopropene (1-MCP). 1-MCP application, on this study, provided an uneven ripening in fruits stored in CA, with more pronounced softening of the pulp in relation to the core. The three CA conditions showed a similar effect on the kiwifruit conservation and the ethylene scrubbing delayed ripening of the fruits during storage and shelf life.

O objetivo deste trabalho foi avaliar a conservação de kiwi Elmwood em função das condições de atmosfera controlada (AC), absorção de etileno e aplicação de 1-MCP. Os tratamentos foram: [1] armazenamento refrigerado (AR), [2] AC com 1,5 kPa O2 e 5,0 kPa CO2 com absorção de etileno, [3] AC com 2,0 kPa O2 e 5,0 kPa CO2 com absorção de etileno [4] AC com 2,0 kPa O2 e 5,0 kPa CO2 , [5] AC com 2,0 kPa O2 e 7,0 kPa CO2 com absorção de etileno. Os frutos de todos os tratamentos permaneceram armazenados durante cinco meses na temperatura de -0,5ºC, com e sem aplicação de 1,0 ppm de 1-metilciclopropeno (1-MCP). A aplicação de 1-MCP, neste trabalho, proporcionou um amadurecimento desuniforme nos frutos armazenados em AC, com o amolecimento mais pronunciado da polpa em relação à columela. As três condições de AC apresentaram um efeito semelhante na conservação do kiwi e a absorção de etileno retardou o amadurecimento durante o armazenamento e na vida de prateleira.