• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.321-322
• /
• 2008

• Journal of Power System Engineering
• /
• v.19 no.1
• /
• pp.83-89
• /
• 2015

A ball strainer screen module, which is used for a condenser tube cleaning system, is a critical mechanical component for maintaining condenser cleanliness. Despite of this importance, not many research have been focused on this module because of its relatively low usage. Employing CFD, this study examines the implication of fluid velocity change and blockage ratio on the ball strainer screen velocity and the static pressure distribution. Through this study, the impact of blockage in the space between ball strainer screen modules is verified. Also, it is found that the ranges of non-dimensional velocity distribution and static pressure distribution decrease as blockage ratio becomes smaller.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.9
• /
• pp.71-78
• /
• 2013

In this paper, the golf club head hit the golf ball moves at a constant velocity, then move in the same direction at a constant velocity of the golf club head, the velocity of the golf ball was hitting and flying the golf ball is calculated. If velocity is different before you hit the golf ball, each of the velocity of the golf ball is calculated. The purpose of this paper is to make it easy to find out the velocity of a club's head, the mass of a golf ball, the velocity or the direction of a golf ball after impact in playing golf. The results of the experiment are represented in tables and figures. And we also propose the comparison analysis between our research and other traditional ones, the implications, and futhur studies in the future. The results of this study, unlike other studies, it was can be seen that measurements of several factors superior to the measurement of the velocity of the golf ball.

• Journal of the Mineralogical Society of Korea
• /
• v.21 no.2
• /
• pp.129-138
• /
• 2008

The characteristics of beneficiating kaolin mineral by liberation (selective grinding) and air classification have been investigated, comparing the grinding rates of ball mill and impact mill. The ore was ground using a ball mill and a impact mill to evaluate the grindability of the two grinding methods based on the constant production amount of fine particles in size less than 325 mesh. Then, the fine product was further separated into two fractions using an air-classifier and each fraction was chemically analyzed to compare the beneficiation efficiency of the two grinding methods. The chemical grade of kaolin mineral decreased as increasing the grinding rate of both the mills. particularly in the case of ball mill because of overgrinding impurities such as quartz and feldspar. In the case of the ball milling, the fine fraction less than 325 mesh was air-classified at a cutting point of $43\;{\mu}m$. The production rate of the air-classified concentrate was found to be 66.2 wt%, removing 5.3% of $Fe_2O_3$ and 34.6% of CaO. Under the same conditions mentioned above with the impact mill, the production rate of the air-classified concentrate was 64.4 wt%, removing 34.2% of $Fe_2O_3$, 67.6% of CaO and 25.0% of $TiO_2$. Therefore, our results indicate that impact mill is superior to ball mill in terms of impurity removal.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.9
• /
• pp.1615-1626
• /
• 1992

In this study, vibrations and resulting acoustic radiations from an elastic beam impacted by a steel ball were studied theoretically and experimentally. First the transverse vibrations of free-free elastic beams are analysed with modal analysis technique. The impact forces are modeled with the Hertz's theory and the contanct duration is compared with the measured values. Also the calculated beam vibrations are verified with the experimental results. Then the acoustic radiations due to the beam vibration are studied numberically and experimentally. The acousticpressure is calculated assuming the beam has an elliptical cross-section. The predicted acoustic pressure is compared with the measured value. It was found that both the predicted beamvibrations using the Hertz's theory and the estimated acoustic pressure under the assumption of an elliptical cross- section are in very good agreements with the measured values.

• KIEAE Journal
• /
• v.14 no.1
• /
• pp.39-48
• /
• 2014

In the previous test, the verification of the standard floor impact source was carried out comparing the physical characteristics with living impact sources. The result was appeared the validation of the standard impact source was very low because of differences of physical characteristics. This study aims to evaluate annoyance and loudness of standard impact source which is used for the measurement of floor impact sound, and to compare the annoyance and loudness of living impact sources which are produced in real life. The impact sources considered are tapping machine, tire and impact ball as standard sources, and nine real sources which were chosen from the existing researches. The result showed differences of annoyance and loudness between standard impact sources and living impact sources, which means the standard impact sources may rate the performance of floor system inappropriately. In the future, the rating method should be examined how the standard impact sources are similar with real sources in the point of rating the performance of floor system.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.174-179
• /
• 2001

In order to investigate the fracture behaviors(perforation modes) and resistance to perforation during ballistic impact of aluminum alloy plate, ballistic tests were conducted. Depth of penetration experiments with 5.56mm-diameter ball projectile launched into 25mm-thickness Al 5052-H34 targets were conducted. A powder gun launched the 3.55g projectiles at striking velocities between 0.6 and 1.0 km/s. radiography of the damaged targets showed different penetration modes as striking velocities increased. Resistance to perforation is determined by the protection ballistic limit($V_{50}$), a statistical velocity with 50% probability for complete perforation. Fracture behaviors and ballistic tolerance, described by perforation modes, are respectfully observed at and above ballistic limit velocities, as a result of $V_{50}$ test and Projectile Through Plates (PTP) test methods. PTP tests were conducted with $0^{\circ}$ obliquity at room temperature using 5.56mm ball projectile. $V_{50}$ tests with $0^{\circ}$ obliquity at room temperature were conducted with projectiles that were able to achieve near or complete perforation during PTP tests. The effect of various impact velocity are studied with depth of penetration.

• Korean Journal of Applied Biomechanics
• /
• v.15 no.1
• /
• pp.1-18
• /
• 2005

The purpose of this study was to evaluate performance characteristics. in the success of team attack during volleyball competition. For this, real game was analyzed using S-VHS video camera for three dimensional cinematography. The contents of this research were receive to set time, set to spike time, setter moving distance, ball position during set and attacker's relative ball position during jump and spike, and open area at spike. Among the various kinematical factors considered in this study, the ball height relative spiker and open area were found to be related to offensive performance. This finding implies that although their direct impact were not significant the other factors could have indirect impact on offensive performance by increasing open area. Thus, receiver, setter, assistant attacker, and main attacker should practice for successful performance in each stage. Lastly, it is necessary to develop kinematic variables to evaluate performance characteristics of players. Further study may consider the best defense position against the attack of the opponent player.

• Fire Science and Engineering
• /
• v.24 no.5
• /
• pp.102-106
• /
• 2010

This paper studied the measurement about the gunpowder residue quantity by using a handgun and we carried out an experiment ignition characteristics of the gunpowder residue for the investigation fire cause into the indoor shooting range in Busan. The measurement of the gunpowder residue quantity is spouted by using a 0.38 inch gun and 9 mm gun. We were carried out evaluation experiments such as impact sensitivity test, static electricity sensitivity test, friction sensitivity test and measuring a flash point for the ignition characteristics about the gunpowder residue. From experiment results, the impact sensitivity and friction sensitivity of the gunpowder residue in comparison with ball powder are highly sensitive and the gunpowder residue ignites at a relatively low temperature.

• Geomechanics and Engineering
• /
• v.32 no.5
• /
• pp.463-474
• /
• 2023

Materials produced with the help of new technology are used in the design of materials used in all science and engineering departments today. A sports engineering and sports equipment department is one of these departments. The use of nanotechnology in sports equipment is one of the most popular uses of this technology today. Nanomaterials have been used in sports equipment for many years, and reputable companies have benefited. Athletes' equipment allows them to display their skills to the fullest extent. It has always been a dream of professional athletes and their coaches to have unique equipment. As a result, engineers have spent all their time and effort solving this problem. Science and engineering can do various things to meet the needs of all sports levels, including specific and detailed designs, the use of appropriate materials, and standardization tests on equipment. However, these aspects must remain aligned with the latest technologies as they develop, just as with other sciences. These technologies, especially nanotechnology, are essential to sports equipment and devices developed today by sports engineers. This article examines the balls that use nanotechnology and can also improve the athlete's performance by using this technology in a specific structure. Using nanotechnology to make nanocomposite poly-hope balls, which makes them lighter and more acceptable, reduces the impact on the ball and increases its movement speed.