• 설비공학논문집
• /
• 제28권12호
• /
• pp.477-482
• /
• 2016

Airtight containers have been widely used in many industries and household. They need a packing for sealing between the inside and outside. Previous packing materials have some drawbacks like stench, stickiness, and difficulty of applying to automated manufacturing systems. So, a new packing material which is harmless and suitable for automation is needed. This study performed a hot plate welding process of thermoplastic elastomer (TPE) as the packing material. The hot plate welding process included a phase change process of solidification and melting. The porosity-enthalpy method was adopted in order to simulate phase change problems. The TPE showed non-Newtonian fluid characteristics during the melting process. Since properties of SEBS are not well-defined, we established TPE properties by observing the melting behavior of TPE. In order to find an optimized condition, a parametric study including packing thickness, shapes, hot plate temperature, and thermal resistance, was conducted.

• 한국대기환경학회지
• /
• 제17권1호
• /
• pp.51-56
• /
• 2001

This study was carried out to interpret mathematically hydraulic behaviour in packing tower which packed 50 mm plastic Hiflow-ring with a dimension of 300 mm wide and 1,400 mm high. In view of energy saving, the recent packing. 50 mm plastic Higlow-ring was superior to conventional packings because of low pressure drop in high loads. As relative error between numerically predicted and experimentally obtained values was less then 6% in the loading and flooding point, it found that therir results appeared to be adequate. Comparison of hose two values in both dry and wet packing conditions. relative errors amount to 3.96 and 5.6%, respectively. In order to evaluate the operating characteristics of packing, the type, size, and material for packings must be estimated in various system and loads. This study is able to calculated pressure drop, hold-up, gas and liquid loads using mathematical interpretation. For these calculation, the specific constants of each packings must be calculated first all. The method of mathematical interpretation in this study turned out to be superior to the existing methods because of reduced errors at loading and flooding point.

• 한국환경과학회지
• /
• 제12권7호
• /
• pp.791-799
• /
• 2003

This study was carried out to get more operational characteristics of the sequencing batch biofilm reactors with media volume/reactor volume ratio of 15 %, 25 % and 35 %. Experiments were conducted to find the effects of the media packing ratio on organic matters and nutrients removal. Three laboratory scale reactors were fed with synthetic wastewater. During studies, the operation mode was fixed. The organic removal efficiency didn't show large difference among three reactor of different packing media ratios. However, from the study results, the optimum packing media ratios for biological nutrient removal was shown as 25%. The denitrifying PAOs could take up and store phosphate using nitrate as electron acceptor.

• 산업경영시스템학회지
• /
• 제34권1호
• /
• pp.97-102
• /
• 2011

This study was performed to design and develop an ergonomic equipment for strawberry sorting and packing in agricultural working environments. Potential risk of work related musculo-skeletal disorders associated with farm workers performing strawberry sorting and packing was analyzed through interviews, field surveys, work measurement, and working posture evaluation. For the evaluation of working posture, we used REBA, OWAS, and RULA assessment methods to identify multi-factorial risk factors. Based on the result of comprehensive assessment, a new concept of multi-level rotating table for strawberry sorting and packing was proposed to modify awkward working postures and improve the effectiveness of the farm work. Finally, the characteristics and effectiveness of new equipment was discussed in terms of improvements in productivity, safety, and subjective ratings of farm workers. The results of analysis showed that working conditions improved significantly.

• 설비공학논문집
• /
• 제14권10호
• /
• pp.775-780
• /
• 2002

An experimental study on the characteristics of several kinds of packing materials was carried out in order to get the optimum design data for the packed-type rectification system of an NH$_3$/$H_2O$ GAX absorption heat pump. Several suitable packing materials were examined and the bulk of steel wire was shown as the most effective packing material in rectifier. The optimum volumetric ratio of packed steel wire in rectifier was obtained as around 36%. The performance results can be adapted in rectifier design of absorption heat pump.

• Bulletin of the Korean Chemical Society
• /
• 제33권4호
• /
• pp.1135-1140
• /
• 2012

An electrochromatographic microchip with carboxyl-group-derivatized mono-disperse silica packing was prepared from the corresponding colloidal silica solution by utilizing capillary action and self-assembly behavior. The silica beads in water were primed by the capillary action toward the ends of cross-patterned microchannel on a cyclic olefinic copolymer (COC) substrate. Slow evaporation of water at the front of packing promoted the self-assembled packing of the beads. After thermally binding a cover plate on the chip substrate, reservoirs for sample solutions were fabricated at the ends of the microchannel. The packing at the entrances of the microchannel was silver coated to fix utilizing an electroless silver-plating technique to prevent the erosion of the packed structure caused by the sudden switching of a high voltage DC power source. The electrochromatographic behavior of the microchip was explored and compared to that of the microchip with bare silica packing in basic borate buffer. Electrophoretic migration of Rhodamine B was dominant in the microchip with the carboxyl-derivatized silica packing that resulted in a migration approximated twice as fast, while the reversible adsorption was dominant in the bare silica-packed microchip. Not only the faster migration rates of the negatively charged FITC-derivatives of amino acids but also the different migration due to the charge interaction at the packing surface were observed. The electrochromatographic characteristics were studied in detail and compared with those of the bare silica packed microchip in terms of the packing material, the separation potential, pH of the running buffer, and also the separation channel length.

• 한국세라믹학회지
• /
• 제32권4호
• /
• pp.462-470
• /
• 1995

The characteristics of spray-dried granules are important for dry pressing operation since they have great influences on die-filling, compaction ratio, and resulting green microstructure. An attempt was made to control granule morphology and the packing structure of fine Si3N4 particles in granules by adjusting suspension property. Mercury porosimetry was used to characterize the pore structures of both granules and green compacts. Finally, the effects of particle packing structure in granules and green microstructure on sintering behavior were investigated.

• 설비공학논문집
• /
• 제18권7호
• /
• pp.571-577
• /
• 2006

The characteristics of ice packing factor (IPF) at the ice slurry system using one line type are compared with the system using two lines type. The installation space for one transporting line is saved at the one line system. For the one line type, the ice packing factor is reduced along the downstream, but for the two lines type, the ice packing factor is fixed. For the one line system, mass flow rate in the main line is fixed along the down-stream, but for two lines system, the mass flow rate in the main line is reduced along the downstream. For one line system, along the down stream after IPF=0, the temperature at the main steam is increased, and the extracted mass flow is increased. The initial IPF, at which the IPF is not arrived at zero upto the final node, is proposed for the B area.

• 한국환경과학회지
• /
• 제21권3호
• /
• pp.305-312
• /
• 2012

This work is to study the variations of adsorption characteristics of binary vapor according to packing system of double-layer bed by fixed bed experiment. Breakthrough curves of single and binary vapor composed of acetone and benzene on single-layer and double-layer adsorption bed composed of activated carbon (AC) and silica-aluminar (SA) were compared. Adsorptions of binary vapor on double-layer bed were influenced by the differences of surface area between adsorbents as well as the polarity difference between adsorbent and adsorbate. The roll-up phenomenon of acetone vapor was happened by replacement with competing adsorption between acetone vapor and benzene vapor on AC bed, but it was not happened on SA bed because acetone vapor and benzene vapor had less difference in affinity with SA bed. The breakthrough times of acetone vapor and benzene vapor on AC/SA double-layer bed were three times and 1.4 times larger respectively than on SA/AC double-layer bed, the differences of breakthrough times were relatively larger than the equilibrium adsorption capacities according to packing system of double-layer bed.

• 한국재난정보학회 논문집
• /
• 제7권1호
• /
• pp.12-20
• /
• 2011

본 연구는 군중집회 및 군중눌림 현상의 문헌조사 및 분석에 근거하여 군중집회 및 군중집회에서의 인명피해의 특성을 알아보고자 수행되었다. 대규모 군중집회 시 인명 피해의 특성은 참가자 수와 군중 밀도가 군중집회 종류와 특성에 따라 다른 영향을 미치고 있었다. 군중 집회에 영향을 주는 변수와 그 원인들은 상황에 따라 다양한 정 혹은 부의 영향을 미치고 있었으며 그 변수들은 날씨, 참가자 수, 행사 기간, 실외와 실내, 착석과 이동, 행사 유형, 군중 감정상태, 술 혹은 약물, 군중 밀도, 관련 시설, 참가자 연령 등이었다. 이 중 군중 눌림현상은 실험적으로도 연구가 가능하였고, 사고가 유발되는 물리적 기전으로 보아 군중 압력과 군중 밀도 및 압력의 지속 시간에 영향을 받았으나 사망에 이르는 구체적인 압력 수치를 도출하려면 인간 신체와 관련된 여러 외부적 영향으로 인하여 추가적 연구가 더 필요하다.