• Journal of Practical Engineering Education
• /
• v.15 no.1
• /
• pp.119-126
• /
• 2023

Today, in order to improve fuel efficiency and dynamic behavior of automobiles, an era of light weight and simplification of automobile parts is being formed. In order to simplify and design and manufacture the shape of the product, various components are integrated. For example, in order to commercialize three products into one product, product processing is occurring to a very narrow area. In the case of existing parts, precision die casting or casting production is used for processing convenience, and the multi-piece method requires a lot of processes and reduces the precision and strength of the parts. It is very advantageous to manufacture integrally to simplify the processing air and secure the strength of the parts, but if a deep and narrow pocket part needs to be processed, it cannot be processed with the equipment's own spindle. To solve a problem, research on cutting processing is being actively conducted, and multi-axis composite processing technology not only solves this problem. It has many advantages, such as being able to cut into composite shapes that have been difficult to flexibly cut through various processes with one machine tool so far. However, the reality is that expensive equipment increases manufacturing costs and lacks engineers who can operate the machine. In the five-axis cutting processing machine, when producing products with deep and narrow sections, the cycle time increases in product production due to the indirectness of tools, and many problems occur in processing. Therefore, dedicated machine tools and multi-axis composite machines should be used. Alternatively, an angle spindle may be used as a special tool capable of multi-axis composite machining of five or more axes in a three-axis machining center. Various and continuous studies are needed in areas such as processing vibration absorption, low heat generation and operational stability, excellent dimensional stability, and strength securing by using the angle spindle.

• Journal of Korea Water Resources Association
• /
• v.48 no.1
• /
• pp.57-67
• /
• 2015

One of main benefits of a dual polarization radar is improvement of quantitative rainfall estimation. In this paper, performance of two representative rainfall estimation methods for a dual polarization radar, JPOLE and CSU algorithms, have been compared by using data from a MOLIT S-band dual polarization radar. In addition, this paper presents evaluation of specific differential phase ($K_{dp}$) retrieval algorithm proposed by Lim et al. (2013). Current $K_{dp}$ retrieval methods are based on range filtering technique or regression analysis. However, these methods can result in underestimating peak $K_{dp}$ or negative values in convective regions, and fluctuated $K_{dp}$ in low rain rate regions. To resolve these problems, this study applied the $K_{dp}$ distribution method suggested by Lim et al. (2013) and evaluated by adopting new $K_{dp}$ to JPOLE and CSU algorithms. Data were obtained from the Mt. Biseul radar of MOLIT for two rainfall events in 2012. Results of evaluation showed improvement of the peak $K_{dp}$ and did not show fluctuation and negative $K_{dp}$ values. Also, in heavy rain (daily rainfall > 80 mm), accumulated daily rainfall using new $K_{dp}$ was closer to AWS observation data than that using legacy $K_{dp}$, but in light rain(daily rainfall < 80mm), improvement was insignificant, because $K_{dp}$ is used mostly in case of heavy rain rate of quantitative rainfall estimation algorithm.

• Childhood Kidney Diseases
• /
• v.9 no.1
• /
• pp.38-45
• /
• 2005

Purpose : The purpose of this study was to analyze the therapeutic effect of plasmapheresis in various pediatric diseases. Methods : Therapeutic plasmapheresis was performed by COBE Spectra centrifugation. Nine cases were included in this study. The number an[;. method of plasmapheresis, together with the progress and prognosis of each case were retrospectively reviewed. Results : The patients' ages ranged from 26 mont]Is to 16 years of age, and the mean age was 9.9 years. There were S males and 4 females. The underlying diseases requiring plasmapheresis included 2 cases of hemolytic uremic svndrome(HUS), 1 case of lupus nephritis, 2 cases of rapidly Progressive glomerulonephritis(RPGN), 1 case of focal segmental glomorulosclerosis(FSGS), 1 case of systemic vasculitis after pulmonary hemorrhage, 1 case of acute renal failure associated with pulmonary hemoIThage, and 1 case of acute rejection after renal transplantation. The average number of plasmapheresis performed was 6.2 times with a range of 3 to 13 times. The patients with HUS, lupus nephritis, ANCA positive systemic vasculitis induced by pulmonary hemorrhage and ARF-associated pulmonary hemorrhage showed a good response to therapeutic plasmapheresis, but the patients with RPGN, refractory FSGS, and acute rejection after renal transplantation were not responsive to treatment. The most common side effect was hypocalcemia which was rarely symptomatic. Vital signs were not compromised. Conclusion : Although it is presumptuous to generalize the therapeutic effects of plasma pheresis in different diseases due to the small number of study subjects, this study shows that plasmapheresis may be an effective therapeutic modality in various pediatrics diseases and should be considered as a therapeutic option.

• Transactions of the KSME C: Technology and Education
• /
• v.3 no.4
• /
• pp.241-248
• /
• 2015

Most of the Stirling cryocoolers used for infrared detector cooling in domestic is imported. Because the cooler has a high price, short life and poor durability, demand for the coolers continues steadily. However, the cooler is highly related to defense and space technology, technology transfer or co-development with the countries having experties in cooler design is very limited. The pulse tube cooler to be developed in this study is such that the mechanical piston in low temperature actuating part is replaced by the gas piston and linear compressor is adopted, which results in low vibration, long life and better durability. It is expected that development of the pulse tube cooler will not only improve our technology to the level of advanced countries, but also enhance the skills in designing and manufacturing of the infrared detector.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.1
• /
• pp.91-100
• /
• 2017

The object of this study was to measure the bioactivity and antioxidant activity of seed from Gardenia jasminoides Ellis fructus (GJE). GJE seeds were performed the extraction of them by chloroform:methanol (CM, 2:1, v/v), 70% ethanol and n-butanol. Sequentially, total phenol content, nitrogen oxide scavenging activity, antioxidant activity and lipid peroxidation inhibition activity of the extracts were investigated. Solvent extract bioactivity of increasing concentrations (0.2, 0.4, 0.6 mg/mL) were significantly increased (p<0.05). GJE seed extracts showed lower activity than positive control (ascorbic acid, BHA, trolox). The highest concentration of CM extracts was obtained in the same manner as the results of analysis of the total phenol contents of the GJE seed, and 70% ethanol extract showed the highest activity of reducing power. The water soluble carotenoids crocin and flavonoid were effective. As a result of this experiment. the seeds of GJE showed excellent antioxidant, and lipid peroxidation inhibitory properties.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.2
• /
• pp.400-409
• /
• 2017

The purpose of this study was to measure the antioxidant and physiological activities of seed from Gardenia jasminoides Ellis fructus (GJE) in Namhae Korea. We determined proanthocyanidin. GJE seed were extracted by 70% ethanol, chloroform:methanol, 2:1 volume ratio (CM) and n-butanol of three solvents. To investigate by the solvent extract of flavonoid content and value as a functional food ingredient of GJE seed through various antioxidant activities were performed. Solvent extract antioxidant activity of increasing concentrations (0.2, 0.4, 0.6 mg/mL) were significantly increased (p<0.05). The content of proanthocyanidin in GJE seed was $70.035{\pm}0.772mg$ catechin eqivalents/g dry weight. As a result of bioactivity assay, by a solvent of seed were found that the relationship with the increase of flavonoid content increased bioactivities. The antioxidant activity of the extract from the other except for the n-butanol extract on seed was observed at a high level. The results suggest that Gardenia jasminoides Ellis fructus seed can be used as a natural antioxidant.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.6
• /
• pp.166-172
• /
• 2016

This paper deals with the seismic qualification of the reflective metal insulation for thermal shielding that is installed on the outer surfaces of the main equipment of the primary coolant system of a nuclear power plant. A small-scale model of the reactor pressure vessel, which has equivalent dynamic characteristics, was designed to be tested in domestic seismic testing facilities in the future. In this study, seismic analysis of the small-scale model installed with metal insulation was performed using equivalent static analysis and response spectrum analysis. The required Response Spectrum for main equipment of the primary coolant system of APR-1400 plant were considered to establish the enveloping response spectrum, which was applied to the seismic analysis model. The results from two seismic analysis methods were compared to show the structural adequacy of the metal insulator design against a safe shutdown earthquake. This study will form the basis for the seismic testing to support the seismic qualification of the reflective metal insulator.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2008.11a
• /
• pp.93-98
• /
• 2008

Haeundae Doosan We've The Zenith project is adjacent to Suyoung-bay, now it is in the process of excavation and foundation work. The main use of the tower is residence which height is 300m and 80 floor, the highest residential reinforced concrete building through the Orient. It is comprised of 3 high- rised buildings and 1 low-rised building, the basement is 230m wide and 200m length sized mass structure. The lateral resistance system is acted effectively against the lateral load and satisfactorily against the wind vibration by the 4 direction extension of the center core wall($700{\sim}800mm$ thickness) and reinforced concrete column set around the slab. Flat-plate slab system(250mm thickness) is adjusted for the slab system and it enables effective work process and shortening the working term by minimizing the ceiling height and not needing to install perimeter beam and drop panel. The strength and serviceability of the structure is able to be monitored and estimated constantly through the health monitoring system during the construction and after the construction.

• Resources Recycling
• /
• v.19 no.3
• /
• pp.24-32
• /
• 2010

In the present work, a new separation system with rotating rakes has been developed to separate the film-based plastics from the recyclable materials, and environment assessment is also carried out during operation of the device. Capacity of the device was about 5.3 ton/hr at a rakes rotation speed of 26.0 rpm (the number of rakes in the 1st, 2nd and 3rd trials were 39, 52 and 48, respectively) and a belt conveyor speed of 38.5m/min, which satisfied the initial design capacity (5.0 ton/hr). Recovery ratio and purity of the plastic films were 92.6% and 96.5%, respectively at a rotation speed of 28 rpm. The levels of noise, vibration and particulate emission were below material standard regulatory limits. Plastic refused fuel (RPF) was also prepared with the recovered films. The calorific value and chlorine content of the prepared RPF were 9,740 kcal/kg and 0.18%, respectively which satisfy the first grade quality specification of the Korean RPF standard. As a result of this work, recovery of energy resources from the municipal solid waste is possible by adopting the developed separation device.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.16 no.2
• /
• pp.213-224
• /
• 2014

Recently, tunnelling with TBM is getting popular for the construction of cable tunnel in urban area. Mechanized tunnelling method using shield TBM has various advantages such as minimization of ground settlement and prevention of vibration induced by blasting that should be accompanied by conventional tunnelling. In Korea, earth pressure balance (EPB) type shield TBM has been mainly used. Despite the popularity of EPB shield TBM for cable tunnel construction, study on the mechanical behavior of cable tunnel driven by shield TBM is insufficient. Especially, the effect of backfill grout injection on the behavior of cable tunnel driven by shield TBM is investigated in this study. Tunnelling with shield TBM is simulated using 3D FEM. The distance of backfill grout injection from the end of shield skin varies. Sectional forces such as axial force, shear force and bending moment are monitored. Vertical displacement at the ground surface is measured. Futhermore, the relation between volume loss and the distance of backfill grout injection from the end of skin plate is derived. Based on the stability analysis with the results obtained from the numerical analysis, the most appropriate injection distance can be obtained.