The ribs of the injection molded article are a necessary shape in order to maintain the rigidity without increasing the material cost. The ribs on the outside of the molded article in the form of a housing are located on the side of the cavity inside in the mold. This paper proposes slotting by machining side-ribs. The slotting was performed through CNC control along the edge profile of the rib width. The machining time and the roughness of the machined surface were compared to verify the machining efficiency and the practicality of the machining method as a side-rib machining method.

In recent European telecommunication base transceiver stations(BTS), a membrane laminated air filter is reported to replace a heat exchanger in order to cool internal digital units of BTS. The concept of using the air filter is for the direct ambient cooling (DAC) of BTS without heat loss generally found in the heat exchanger type BTS. In the present study, a performance evaluation experiment was conducted to investigate the pressure drop characteristics with dust loading and the particle collection efficiency of the air filter for the DAC of BTS. Finally, the long term operation lifetime of the air filter for BTS was suggested with a given fan rotation speed.

Activated carbon fiber (ACF) filters are widely used to remove volatile organic compounds (VOCs) in air cleaning devices. The performance of ACF filters could be enhanced combining adsorption process with photodegradation process. In this study, to investigate this enhancement effect, a duct-type reactor was made and TiO2 was i㎜obilized on a co㎜ercialized ACF filter. Benzene, toluene, and m-xylene (BTX) were chosen as target compounds. Removal experiments for BTX were done under different air velocity and upstream concentration conditions. The range of inlet concentration was 200～1,400 ppb and the air velocities were 0.4, 0.7 and 1.0 m/s. Adsorption by an ACF filter alone showed high removal efficiency of BTX, depending on the BTX species, the upstream concentration, and the air velocity. The combination of TiO2 and ACF filter significantly increased removal of benzene which was less removed than other pollutants by an ACF filter alone. It was found that the combination effect was small in removal test of toluene and m-xylene. Removal efficiency in the tested experimental conditions was decreased in order of toluene > m-xylene > benzene.

In order to develop combination air filters for air conditioners, 2 types of charging section were constructed. One was the wire-plate type and the other was the scroll type. Each charging section was combined with the same electrostatic polypropylene (PP) media. NaCl aerosol particles with geometric mean diameter of 0.05∼0.16㎛, geometric standard deviation of 1.6∼1.9 and total number concentration of 1,700∼24,000 particles/㎤ were used to determine collection efficiencies of the combination air filters for air conditioners with respect to particle size. It was shown that the scroll type combination air filter has greater collection efficiencies and lower pressure drops than the wire-plate type one does.