This study investigated the effect of the grinding media of a ball mill under various conditions on the raw material of copper powder during the milling process with a simulation of the discrete element method. Using the simulation of the three-dimensional motion of the grinding media in the stirred ball mill, we researched the grinding mechanism to calculate the force, kinetic energy, and medium velocity of the grinding media. The grinding behavior of the copper powder was investigated by scanning electron microscopy. We found that the particle size increased with an increasing rotation speed and milling time, and the particle morphology of the copper powder became more of a plate type. Nevertheless, the particle morphology slightly depended on the different grinding media of the ball mill. Moreover, the simulation results showed that rotation speed and ball size increased with the force and energy.

Particle morphology change and different experimental condition analysis during composite fabrication process by traditional ball milling with discrete element method (DEM) simulation were investigated. A simulation of the three dimensional motion of balls in a traditional ball mill for research on the grinding mechanism was carried out by DEM simulation. We studied the motion of the balls, the ball behavior energy and velocity; the forces acting on the balls were calculated using traditional ball milling as simulated by DEM. The effect of the operational variables such as the rotational speed, ball material and size on the flow velocity, collision force and total impact energy were analyzed. The results showed that increased rotation speed with interaction impact energy between balls and balls, balls and pots and walls and balls. The rotation speed increases with an increase of the impact energy. Experiments were conducted to quantify the grinding performance under the same conditions. Furthermore, the results showed that ball motion affects the particle morphology, which changed from irregular type to plate type with increasing rotation speed. The evolution was also found to depend on the impact energy increase of the grinding media. These findings are useful to understand and optimize the particle motion and grinding behavior of traditional ball mills.

미구엘 시카트(M. sicart)는 불쾌한 게임 디자인이 디자이너와 플레이어간의 상호작용을 발생시키며 이 를 통해 게임이 예술의 영역에서 해석될 수 있음을 시사 하였다. 본 논문에서는 이 불쾌한 게임디자인을 고프먼의 프레임 이론에 바탕하여 재해석한다. 보편적인 게임학이 추구하는 ‘사용자 중심’적 게임 디자인 은 게임의 플레임에 몰입하여 사용자 경험과 게임의 프레임에 일치감을 더하는 긍정적 다운키잉(Positive Down-keying)을 추구한다고 볼 수 있다. 반면에 불쾌한 게임 디자인은 게임의 프레임에 대한 플레이어의 관점에 ‘혼란함’을 주어 게임에 대한 반성적 관점을 가질 수 있도록 해준다. 예술의 영역에서 게임을 해 석하기 위한 방편에서 불쾌한 게임 디자인을 정의했던 시카트 이론은 불쾌한 게임 디자인과 전형적인 게 임 디자인을 나눠서 보지만 플레임 분석을 통한 불쾌한 게임 디자인은 게임 플레이에 대한 플레이어의 반성적 시각을 환기시키는 장치 혹은 테크닉으로 기존의 게임디자인과 관계할 수 있음을 알려주고 있다.