The precipitation behaviour during quenching of cast Al-7Si-0.3Mg aluminium alloy was investigated by DSC in the cooling rate range of 0.01 K/s to 3 K/s and by quenching dilatometry for higher rates. Two main precipit...The precipitation behaviour during quenching of cast Al-7Si-0.3Mg aluminium alloy was investigated by DSC in the cooling rate range of 0.01 K/s to 3 K/s and by quenching dilatometry for higher rates. Two main precipitation reactions were observed during cooling, a high temperature reaction starting almost directly with quenching from 540℃ and a low temperature reaction starting at about 400℃. Quenching with 3 K/s already significantly suppresses precipitation during quenching. Hardness after T6 ageing increases with increasing quenching rate, due to the increasing content of supersaturated solid solution. By dilatometry and hardness results the critical cooling rate can be estimated as about 60 K/s. Quenched Al-7Si-0.3Mg microstructures have been investigated by light microscopy. The microstructures consist of an aluminium-silicon eutectic structure, aluminium solid solution dendrites and precipitates inside the aluminium dendrites, depending on quenching rate.展开更多
Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population cont...Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population continues to decrease. Well aware of this situation, businesses and offices are seeking ways to enhance the intellectual productivity of their workers. This paper explores environmental elements of work spaces that might stimulate intellectual activity. Using a CAD （AutoCAD） miniature garden program, subjects were asked to design a project room that is optimized for creative work using a certain number of elements--11 types of walls, 14 types of floors, 4 types of scenery, 3 types of furniture and 3 types of plantings--but the subjects were free to position and arrange these elements any way they want. The subjects were then interviewed using the evaluation grid method. Based on the results, we created an evaluation structure diagram by analyzing key words and phrases emphasized by subjects in the interviews. The overall evaluation structure represents a summary overview of all 30 subjects who participated in the experiment. This approach captures all the key elements of the office environment that might be used to stimulate intellectual activity of employees.展开更多
文摘The precipitation behaviour during quenching of cast Al-7Si-0.3Mg aluminium alloy was investigated by DSC in the cooling rate range of 0.01 K/s to 3 K/s and by quenching dilatometry for higher rates. Two main precipitation reactions were observed during cooling, a high temperature reaction starting almost directly with quenching from 540℃ and a low temperature reaction starting at about 400℃. Quenching with 3 K/s already significantly suppresses precipitation during quenching. Hardness after T6 ageing increases with increasing quenching rate, due to the increasing content of supersaturated solid solution. By dilatometry and hardness results the critical cooling rate can be estimated as about 60 K/s. Quenched Al-7Si-0.3Mg microstructures have been investigated by light microscopy. The microstructures consist of an aluminium-silicon eutectic structure, aluminium solid solution dendrites and precipitates inside the aluminium dendrites, depending on quenching rate.
文摘Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population continues to decrease. Well aware of this situation, businesses and offices are seeking ways to enhance the intellectual productivity of their workers. This paper explores environmental elements of work spaces that might stimulate intellectual activity. Using a CAD （AutoCAD） miniature garden program, subjects were asked to design a project room that is optimized for creative work using a certain number of elements--11 types of walls, 14 types of floors, 4 types of scenery, 3 types of furniture and 3 types of plantings--but the subjects were free to position and arrange these elements any way they want. The subjects were then interviewed using the evaluation grid method. Based on the results, we created an evaluation structure diagram by analyzing key words and phrases emphasized by subjects in the interviews. The overall evaluation structure represents a summary overview of all 30 subjects who participated in the experiment. This approach captures all the key elements of the office environment that might be used to stimulate intellectual activity of employees.
