• Transactions of Materials Processing
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• v.22 no.2
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• pp.67-73
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• 2013

The deformation characteristics and microstructure changes in a round copper pipe under biaxial compression was studied using a horizontal compression die. The change of material properties, punch load and deformation behavior were monitored using various compressive deformation rates in the range of 0.5mm/min.~450mm/min. The strains, either tensile or compressive, were estimated from Vickers microhardness test results. The punch load and deformation characteristics of the round copper pipes were found to change greatly at a deformation rate of about 200mm/min. The punch load decreased with increasing compressive deformation rate. The results of numerical simulations agreed well with what was expected from the final microstructure and the hardness profile estimated from the final deformation strains.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.246-249
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• 2006

This paper presents experimental studies on investigating the seismic retrofit performance of reinforced concrete rectangular columns with poor lap-splice details using GFRP wrapping. Six columns have been tested. The GFRP retrofitted columns with same 7.5 mm thickness have two section shapes, i.e., rectangular and elliptical sections. The GFRP height was changed from 450 mm to 900 mm. The performance of GFRP retrofitted columns which have different shapes and height are verified.

• The Journal of Sustainable Design and Educational Environment Research
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• v.10 no.2
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• pp.1-7
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• 2011

An experimental study to evaluate structural capacity of an embedded plate connected with prestressed concrete beam was performed. Embedded steel plates and prestressed concrete beam were connected with stud-bolts at the ends of concrete beam specimens. About 1,000 kN concentrated load was applied at 450mm away from the end of beam specimen. A 3,000 kN capacity static Oil-jack was used to direct concentrated load. The maximum strain of stud-bolt recorded $90{\times}10^{-6}$(mm/mm) and wide width cracks were not founded. Any falling failures of concrete and large deformations were not founded either between steel plate and prestressed concrete specimen. As a result, construction performance can be improved using this embedded steel plate connection system apply to large space educational facilities.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.271-274
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• 2005

In this research, 13 RC slabs connected by hinged joints were tested. the new slab was connected to the existing slab by hinge joint injecting dowel bars between two slabs. Main parameters of the slabs were the spacing of the dowel bars (150mm, 300mm, and 450mm) and the locations of the longitudinal reinforcement of the old slab. The test results indicated that the joint strength of the RC test slabs having various types of dowel bars was about twice that calculated by the ACI 318-02 code. The locations of the longitudinal reinforcement of the old slab slightly increased the strength of the slabs connected by hinged joints.

• Journal of IKEEE
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• v.25 no.3
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• pp.445-450
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• 2021

Bio-impedance measurement is a measurement device that can be used to obtain biometric information and diagnose skin diseases using convenience, low cost, and low cost devices. In this study, the bio-impedance was measured using a direct dry gold electrode and a simulation study through animal bio modeling to obtain biometric information in a biometric form. Impedance was measured by inserting electrodes into subcutaneous areas of animal tissue and applying frequencies of 100 uA, 1-100 kHz using a two-electrode method. As a result of the measurement, the resistance of the electrodes is measured high at 5 mm electrodes compared to 7.5 mm and 10 mm electrodes based on 5 mm electrodes. Based on the 5 mm electrode, an average difference of 1.49% was found for the 7.5 mm electrode in the total frequency range, and the impedance difference was confirmed to be 2.624% for the 10 mm electrode. In the future, the research results are expected to be valuable in designing and manufacturing electrodes for bio-inserted electrocardiogram sensors.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.25-32
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• 2001

A microwave vacuum (MW/V) dryer was developed for drying short roundwoods, from which woodcraft souvenirs in Korean market are mostly made, and which were hardly dried without defects in a conventional kiln. It consisted of three 1.5 kW magnetrons of 2,450 MHz, a vacuum pump, a load cell of 100 kg and a cavity of $580{\times}580{\times}1,360\;mm^3$. A computer program was developed to switch on or off the magnetrons according to drying schedules, those were based on microwave injection time or the average of wood temperatures. To evaluate the new MW/V dryer the roundwood specimens of rigida pine, poplar and birch were dried. Their log diameters and lengths ranged from 125 to 25 em and from 25 to 50 cm, respectively. In spite of the presence of minor drying defects, the MW/V drying is found to be an effective method for drying short roundwoods. Wooden turneries made of red alder and ash logs were also MW/V dried from green to 4%MC without any degradation. The rates of the MW/V drying were examined for three different lengths of poplar logs.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.591-597
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• 2023

Pakistan depends heavily on imports for its fuel requirements. In this experiment, catalytic pyrolysis of a blend of feedstock's consisting of date seed, wheat straw, and corn cob was conducted in a fixed bed reactor to produce oil that can be used as an alternative fuel. The main focus was to emphasize the outcome of important variables on the produced oil. The effects of operating conditions on the yield of bio-oil were studied by changing temperature (350-500 ℃), heating rate (10, 15, 20 ℃/min), and particle size (1, 2, 3 mm). Moreover, ZnO was used as a catalyst in the process. First, the thermal degradation of the feedstock was investigated by TGA and DTG analysis at 10 ℃/min of different particle sizes of 1, 2, and 3mm from a temperature range of 0 to 1000 ℃. The optimum temperature was found to be 450 ℃ for maximum degradation, and the oil yield was indicated to be around 37%. It was deduced from the experiment that the maximum production of bio-oil was 32.21% at a temperature of 450 ℃, a particle size of 1mm, and a heating rate of 15 ℃/min. When using the catalyst under the same operating conditions, the bio-oil production increased to 41.05%. The heating value of the produced oil was 22 MJ/kg compared to low-quality biodiesel oil, which could be used as a fuel.

• Journal of Korean Society of Steel Construction
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• v.13 no.4
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• pp.381-393
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• 2001

The current traffic situation in Korea can be described as rapid change in traffic volume and diversity in vehicle size from compact cars to large trucks. W-beam barrier most widely used in Korea was found not to satisfy the stiffness requirement for the Koran impact condition of 14 ton-60Km/h-15deg. and it was too stiff for small vehicles impacting with more realistic speed to satisfy the safety of vehicle occupants. To develop a guardrail system satisfying the two contradicting goals, a thrie-beam guardrail system, which had the beam thickness of 3.2mm and rubber cushions, was conceived. Even though the height of the thrie-beam(450mm) is increased by 100mm as compared to that of W-beam (350mm), there was only 2% increase in the weight of the thrie-beam. The new thrie-beam barrier system could contain more wide range of vehicle bumper heights, and showed better performance in the viewpoint of stiffness and energy absorbing capability than the W-beam system. The impact performance was evaluated from a crash test. The developed thrie-beam guardrail system satisfied all applicable criteria for NCHRP 350 test designation 3-10.

• The Korean Journal of Mycology
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• v.31 no.1
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• pp.1-7
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• 2003

One hundred fifty one specimens of Beauveria spp. from 19 different locations were collected from September 1 to August 31, 2002. Most of the isolates were identified as Beauveria. bassiana. Cordyceps staphylinidaecola collected from Mt. Obong in Chunchon City covered the host with mycelia which were produced 1 to 4 stromata along with asexual spores. The size of bright yellow ununiform stromata were about 45 mm and the head about $17mm{\times}4mm$. Perithecia completely immersed were $530{\sim}550{\times}290{\sim}300{\mu}m$ in size and mainly scattered on the head. Ascospore produced in asci in the size of $400{\sim}450{\times}4{\sim}5{\mu}m$ developed thread-like secondary spores, which were directly separated into secondary conidial spores. Conidia produced at apical portion of synnemata were $2.6{\sim}3.4{\times}1.2{\sim}1.9{\mu}m$ in size. High density of mycelium was observed at $25^{\circ}C$ ranged from pH 6.5 to 8.5 after 11 days of inoculation. It took 15 to 18 days after inoculation to fully grow on the medium mixed brown rice with pupa. Mycelium developed stromata on the medium 30 days after completion of mycelial growth, where perithecia were produced in 40 days.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.123-128
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• 1997

In-situ bearing metal temperature and shaft vibration are measured for an unload type and a preload type, m=0.87, of vertical guide bearing for hydraulic pump-turbines. Guide bearing is a tiltingpad type journal bearing consisting of eight pads whose diameter is 1,450 mm. Rotational speed is 450 rpm. Both the bearing metal temperature and the shaft vibration are very high in the unload type but are slight in the preload type, comparatively. The bearing metal temperature is decreased due to the increase of cooling effect by the increase of preload and the shaft vibration is decreased due to the increase of bearing stiffness. It is concluded that the preload effect of a guide bearing for hydraulic pump-turbines has a large influence on the bearing metal temperature and the shaft vibration.