Noises in each construction field cause residents in the neighborhood to make complaints due to their high sound pressure level and repetitive, shocking sound. While South Korea regulates construction noises on the basis of legal criteria to minimize the damage from the noises, the regulation only involves a weighted sound level (dB(A)), which is loudness, like other types of noises. It is therefore necessary to make typology of construction noise sources and evaluation vocabularies with the objective of making criteria for regulating construction noises suitable for the South Korean situation. While research based on a survey has been conducted to make typology of construction noise sources and evaluation vocabularies, there have been lots of difficulties in using it to make criteria for regulation because no consideration was given to psychological responses of people. On the basis of the findings from literature review, this study aimed to make typology of construction noise sources and vocabularies through a psycho-acoustic experiment and analyze the psychological characteristics and meanings of construction noises more accurately. The respondents’ psychological responses to construction noise sources were grouped into three factors ‘normal, shocking, and fluctuating noises’ and into ― ― six factors ‘annoying,’ ‘loud,’ ‘confusing,’ ‘noisy,’ ‘alarming,’ and ‘boisterous’ in terms of evaluation ― ― vocabularies. Since the factor with the biggest eigenvalue drawn from the respondents’ psychological responses is most important, the most important influential factor in evaluating construction noises was ‘normal noises’ for construction noise sources and ‘annoyance’ for evaluation vocabularies. This typology is expected to be useful to make and revise criteria for regulating construction noises.
The object of this paper is to estimation of noise reduction effect of road noise by operating condition due to tire noise regulation. A prepare the countermeasure of the noise reduction according to collect tire/road noise data under various influencing factors by using the tire test method. To accomplish the object : A automotive is used as a test platform to test tire/road noise by changing different types of tires and using the On-Board Sound Intensity test system. The influence of inflation pressure, road, load, speed and pattern type on tire/road noise is compared and analyzed. At the same time, the mechanism of tire/road noise is analyzed, which provides an experimental basis for tire noise reduction.
Oxide-dispersion-strengthened (ODS) alloy has been developed to increase the mechanical strength of metallic materials; such an improvement can be realized by distributing fine oxide particles within the material matrix. In this study, the ODS layer was formed in the surface region of Zr-based alloy tubes by laser beam treatment. Two kinds of Zr-based alloys with different alloying elements and microstructures were used: KNF-M (recrystallized) and HANA-6 (partial recrystallized). To form the ODS layer, Y2O3-coated tubes were scanned by a laser beam, which induced penetration of Y2O3 particles into the substrates. The thickness of the ODS layer varied from 20 to 55 μm depending on the laser beam conditions. A heat affected zone developed below the ODS layer; its thickness was larger in the KNF-M alloy than in the HANA-6 alloy. The ring tensile strengths of the KNF-M and HANA-6 alloy samples increased more than two times and 20–50%, respectively. This procedure was effective to increase the strength while maintaining the ductility in the case of the HANA-6 alloy samples; however, an abrupt brittle facture was observed in the KNF-M alloy samples. It is considered that the initial microstructure of the materials affects the formation of ODS and the mechanical behavior.
The flow characteristics around the vertical wall with the flap were visualized in the water channel using PIV. And the effect of flap angle change was investigated to see how quickly the spreading can be prevented and confined if oil spill occurs at sea. As a result, the fluid in the front of the vertical wall flows constantly, Nearing a boundary layer on the vertical wall, and a flow separation phenomenon occurs. Thereafter, flow loss or depth loss to the bottom of the vertical wall was confirmed. Also, it was observed that irregular reverse circulation flow occurred due to flap angle change and pressure gradient at the back of vertical wall. In this study, it was analyzed that it is most effective at 20 degrees angle. In the future, it is necessary to confine the flow characteristics of PIV and CFD by assuming that there is a double vertical wall in which oil having a lower specific gravity than water is trapped in the oil fence.
Copper electroplating and electrode patterning using a screen printer are applied instead of lithography for heterostructure with intrinsic thin layer(HIT) silicon solar cells. Samples are patterned on an indium tin oxide(ITO) layer using polymer resist printing. After polymer resist patterning, a Ni seed layer is deposited by sputtering. A Cu electrode is electroplated in a Cu bath consisting of Cu2SO4 and H2SO4 at a current density of 10 mA/cm2. Copper electroplating electrodes using a screen printer are successfully implemented to a line width of about 80 μm. The contact resistance of the copper electrode is 0.89 mΩ·cm2, measured using the transmission line method(TLM), and the sheet resistance of the copper electrode and ITO are 1 Ω/□ and 40 Ω/□, respectively. In this paper, a screen printer is used to form a solar cell electrode pattern, and a copper electrode is formed by electroplating instead of using a silver electrode to fabricate an efficient solar cell electrode at low cost.
The aim of this study was to select compounds for the standardization of fermented Kalopanax pictus Nakai (KP-F), to develop the analysis method using HPLC-PDA and to perform method validation. KP-F is a fermented powder developed to improve the original physiological activities and create a new functionality. Eleutheroside E, Acanthoside B, and Syringaresinol were selected as the standard compounds and developed our own method for simultaneous analysis. The analyte was isolated using C18 column with a gradient elution of 0.05 M phosphoric acid in water and methanol as the mobile phase at a flow rate of 1 mL/min and detected at 210 nm. As a result, all standard compounds showed good linearity with an R2 (coefficient of correlation) of 1.000 and for the limit of detection range of 0.710~0.831 μg/mL, and the limit of quantification as 2.150~2.520 μg/mL. The precision was RSD (%) of less than 4.80%, while the accuracy was 4.70%>RSD (%) for the range 102.44~110.48%. In conclusion, the developed analysis method is suitable for the detection of Eleutheroside E, Acanthoside B, and Syringaresinol in KP-F.