• Journal of Korean Society of Steel Construction
• /
• v.26 no.3
• /
• pp.191-204
• /
• 2014

In this paper a systematic numerical analysis is performed to obtain the bending moment resisting capacity of a top and seat angle connection, which is a type of partially restrained connection, for a CFT composite frame subjected to cyclic loading. This partially restrained composite CFT connections are fabricated using high strength steel connection bar. The three-dimensional nonlinear finite element models are constructed to investigate the rotational stiffness, bending moment capacity, and failure modes. A wide scope of additional structural behaviors explain the different influences of the top and seat angle connection's parameters, such as the different thickness of connection angles and the gage distances of the high strength steel bar. The moment-rotation angle relationships obtained from the finite element analysis are compared with those from Richard's theoretical equation.

• Journal of the Korean Vacuum Society
• /
• v.22 no.5
• /
• pp.231-237
• /
• 2013

New method of volume measurement for reference weights of a pressure balance using a gas pycnometer is proposed. The result of volume measurement of proposed method shows the uncertainties of approximately 0.2% at the level of confidence of 95% for reference weights in the ranges of 1 kg, 2 kg, and 5 kg. This measuring system consists of a sample chamber, an expansion chamber, a precision pressure gage, a precison thermometer, a vacuum pump, and helium as a medium gas. The measurement principle of this proposed method is based on Boyle's law. This method will contribute a reliability of the volume measurements of reference weights for a pressure balance to the national measurement standard.

• The Journal of the Society of Korean Medicine Diagnostics
• /
• v.10 no.1
• /
• pp.78-97
• /
• 2006

Background: There was seldom study about method that estimate expertness of pulse diagnosis in 8 Constitution Medicine in spite of the diagnostician importance in 8 Constitution Medicine Objectives: This study is to evaluate diagnostician's consistency and accuracy about pulse diagnosis in 8 Constitution Medicine using Cage R&R study. Methods: The subjects were comprised of 28 volunteers. Among theme, 3 diagnosticians and 10 participants were chosen through questionnaire. Diagnosticians diagnosed participant's Constitution by pulse diagnosis in 8 Constitution Medicine with hiding their eyes by eyepatch. MINITAB statistical software(ver. 13.20) was used for statistical analysis: Attribute Cage R&R study was used to verify the results. Results: 1. In the measurements of consistency, diagnostician b(agreement=80%, Value of k=0.8276)was very good, diagnostician a(agreement=70%, Value of k=0.7465) was good, and diagnostician c(agreement=50%, Value of k=0.5365) was moderate. 2. In the measurements of accuracy, diagnostician b(agreement =70%, Value of t=0.6812) was good, diagnostician a(agreement=60%. Value of t=0.6414) was good, and diagno-stician c(agreement=0%, Value of k=-0.1000) was poor. 3. In cofidence of diagnosis, diagnostician c was 75%, diagnostician a was 70%, and diagnostician b was 64%. Conclusion: The results suggest that diagnostician's consistency and accuracy about pulse diagnosis in 8 Constitution Medicine can be evaluated by Cage R&R study. further study is needed for estimation method of pulse diagnosis in 8 Constitution Medicine.

• Journal of the Korean Society for Precision Engineering
• /
• v.9 no.1
• /
• pp.106-117
• /
• 1992

In this study, the propagation behaviour and the closure phenomena of physically small surface cracks were investigated by the techinque of the Kikukawa-unloading elastic compliance method using a back face strain gage. The surface cracks initiated and propagated from notched specimens under constant amplitude bending load. The crack shape (aspect ratio) with approximately semi-circular at the early stage was changed to semi-elliptical as the cracks grew larger. The crack depth (a) could be expressed uniquenly by the crack length (c). The dependence of the crack propagation rate on the stress ratio R was strongly related in the lower ${\Delta}K$ range. The deceleration of the surface crack propagation rate was prominent in lower R during the crack length was small. When the propagation rate was rearranged with the effective stress intensity factor range ${\Delta}$K_{eff} the dependence of the crack propagation rate on the stress ratio R was found to be diminshed. These were caused by the crack closure phenomena that was most prominent at the lower propagation rate. The mechanism of crack closure phenomena was dominated by the plasticity-induced mechanism.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.27 no.2
• /
• pp.173-182
• /
• 2007

Cracks in concrete structures should be measured to periodically assess potential problems in durability and serviceability. Conventional crack measurement systems depend on visual inspections and manual measurements of the crack features such as width, length, and direction using microscope and crack gage. However, conventional methods take long time as well as manpower, and lack quantitative objectivity resulted by inspectors. In this study, an evaluation technique for concrete surface cracks is developed using image processing and artificial neural network. Developed technique consists of three major parts: (1) crack detection (2) crack analysis and (3) pattern recognition. To examine validity of the technique developed in this study, crack analyzing tests were performed on the images obtained from various types of concrete surface cracks. The test results revealed that the system is highly effective in automatically analyzing concrete surface cracks in terms of features and patterns of cracks.

• Journal of Korean Society of Steel Construction
• /
• v.25 no.5
• /
• pp.543-553
• /
• 2013

As the deep deck plate has the shape of open cross section, It can cause structural problems such as bending torsions due to instability of the section. There are a number of fasteners types which are frequently used on light gage steel diaphragms such as bolts, rivets, welds, and screws. In this study, the structural capacity of the self drilling screw connection between the deep deck and the reinforced cap plate was evaluated by experimental variables such as the arrangement method, numbers of screw, pitch of screw, and head plate thickness.

• Journal of Korean Society of Steel Construction
• /
• v.29 no.6
• /
• pp.423-434
• /
• 2017

In this paper a systematic numerical analysis is performed to obtain the hysteresis behavior of partially restrained top and seat angle connections subjected to cyclic loading. This connection includes superelastic shape memory alloy (SMA) angles and rods in order to secure the recentering capacities as well as proper energy dissipation effects of a CFT composite frame. The three-dimensional nonlinear finite element models are constructed to investigate the rotational stiffness, bending moment capacity and failure modes. A wide scope of additional structural behaviors explain the different influences of the connection's parameters, such as the various thickness of connection angles and the gage distance of steel and SMA rods.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.16 no.3
• /
• pp.178-189
• /
• 2004

For designing a reliable harbor, a methodology for estimating design waves of 97.5% operable harbor condition is suggested using long-term wave data. For a practical application of the methodology, a marine police harbor was selected as a site. Wave data used were collected from February 1993 to December 2003 at Jodo wave gage station in front of Pusan harbor. Joint distributions of significant wave height and significant wave period for specified wave directions were obtained and used to feed as input waves for parabolic mild-slope wave model. Results showed that input waves with significant wave height of 1.75 m, significant wave period off sec and wave direction E yield design waves height of 1.06 m at the site of interests, which is a 97.5% operable harbor condition. Wind waves generated inside harbor showed to be no effect on the design wave condition. Swells propagated from deep water into harbor are shown to be dominant effects on the design waves of operable harbor condition.

• Applied Biological Chemistry
• /
• v.36 no.2
• /
• pp.86-92
• /
• 1993

Myrosinase from radish was purified by DEAE Bio-Gel, Con-A, and Superose-6 column. The purified myrosinase(II) possessed 2 subunits, and their molecular as determined by SDS-polyacrylamide gel electrophoresis were 53 and 39 KD, respectively. The specific activity of purified enzyme was 37,500 units/mg. The enzyme was purified approximately 44-fold compared to the crude enzyme. Optimum pH of the myrosinase was $6.5{\sim}7.0$ in phosphate and Tris-HCl buffer solutions. Optimum temperature of the enzyme was $37{\sim}38^{\circ}C$. The enzyme was stable at pH 7.0, and less than $30^{\circ}C$. Cu or Hg ion significantly inhibited the enzyme activity, but ascorbic acid enhanced, resulting in a maximum activity by 1 mM ascorbic acid. Among the ascorbic acid analogues, dehydroascorbic acid did not affect, whereas others showed a little effect, but less than ascorbic acid itself. Individual 2-mercaptoethanol and dithiothreitol (reducing agents) did not enhance the enzyme activity. but 2-mercaptoethanol effect was enhanced when mixed with ascorbic acid.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.60 no.6
• /
• pp.111-119
• /
• 2018

The air-void is known to be one of the influencing factors for estimating long-term performance of asphalt concrete. Most of all, confirming air void or density of pavement layer is important for quality control of field compaction level of asphalt concrete pavement. In this study, a non-nuclear type non-destructive density gage (NDDG) was used to estimate compacted air-voids of asphalt pavement as a non-destructive test method. Asphalt concrete slab specimens were prepared using 6 types of asphalt mixes in laboratory (lab) for lab NDDG test. Four different base structure materials were used to find out if there were any differences due to the type of base structure materials. The actual air-voids and NDDG air-voids were measured from 6 asphalt concrete slabs. Four sections of field asphalt pavements were tested using the NDDG, and actual air voids were also measured from field cores taken from the site where the NDDG air-void was measured. From lab and field experimental tests, it was found that the air-voids obtained by NDDG were not the same as the actual air-voids measured from the asphalt concrete specimen. However, it was possible to estimate air voids based on the relationship obtained from regression analysis between actual and NDDG air voids. The predicted air-voids based on the NDDG air-voids obtained from 50mm depth were found to be reliable levels with $R^2{\fallingdotseq}0.9$. Therefore, it was concluded that the air-voids obtained from NDDG could be used to estimate actual air-voids in the field asphalt pavement with a relatively high coefficient of determination.