• Fire Science and Engineering
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• v.27 no.6
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• pp.1-7
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• 2013

In this study, the effects of various disk shapes of hydrant on the pressure drop are experimentally and numerically analyzed. The test methods for measuring pressure drop of hydrant are comply with standard of Underwriters Laboratory (UL). The hydrant as used in this study has one inlet, diameter 150 mm, and three outlet, 114.3 mm diameter for one outlet and 63.5 mm diameter for the others. The pressure of the hydrant are measured in the range 760 L/min~2,270 L/min for 63.5 mm outlet and 3,030 L/min~6,060 L/min for 114.3 mm outlet. Also, the numerical results of pressure drop are compared with the experiments to verify the accuracy and to analyze the of various valve shape of hydrant on the pressure drop. The engineering parameters, flow coefficients, are reduced from 181.57 to 136.35 ($L/min/kPa^{0.5}$) with inclined angle of disk from $0^{\circ}$ to $45^{\circ}$. These results are able to practical use for design hydrant to minimize pressure drop.

• The Korean Journal of Malacology
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• v.29 no.3
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• pp.207-216
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• 2013

Changes in density of manila clam, Ruditapes philippinarum to environment, catch and recruitment were studied in a few stations (Seonjae, Seongam, Hwangdo and Padori) in the West coast area of Korea from January, 2007 to December, 2009. Water temperature, salinity, dissolved oxygen and pH in the study stations were 0.8 to $31.2^{\circ}C$, 22.1 to 33.7 psu, 5.0 to 12.0 mg/L and 7.39 to 8.99, respectively. The concentrations of dissolved inorganic nitrogen, phosphate and silicate were 0.016 to 1.281 mg/L, 0.004 to 0.093 mg/L and 0.016 to 1.617 mg/L, respectively. Chlorophyll-a ranged from 0.2 to 12.1 ${\mu}g/L$, respectively. Substrata were mainly composed of muddy sand and very poorly sorted in Padori, muddy sand and well sorted in Seonjae and Hwangdo, gravelly muddy sand and poorly sorted in Seongam. Density was high in Seonjae and Seongam, but low in Hwangdo and Padori. In clam culture station, in which spat was naturally produced without sowing seedlings, the living density was decreased by increasing of death and a catch of shellfish, and recruitment was changed. Also, Density affected condition factor and shape of clam. Condition factor was the highest in Hwangdo, in which temperature in the winter and chlorophyll-a were high, and was the lowest in Padori. In the shape of clam, the shape in Seongam was a elongated form, but in Padori was a stunted form.

• Journal of Sensor Science and Technology
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• v.6 no.6
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• pp.500-507
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• 1997

For fine control of operating temperature of shape memory alloy, we investigated the effect of thermal teratment of shape memory alloy with the impurity kind. The martensitic transformation temperature in a Cu-17.25Zn-15Al and Cu-17.25Zn-15Al-1Ag/Fe was measured using electrical resistivity as a function of quenching temperature. Order-disorder phase transition temperatures in parent phase were measured and kind of transition were distinguised by DSC(differential scanning calorimeter) with heating rate variation. And structual changes were studied with XRD. For the Cu-17.25Zn-15Al shape memory alloy, the order-disorder phase transition temperature, $T_{B2}$ and $T_{L21}$ was 809K and 610K and for the Cu-17.25Zn-15Al-1Ag and Cu-17.25Zn-15Al-1Fe specimen $T_{B2}$ and $T_{L21}$ was 794K and 610K, and 803K and 613K, respectively. In all the specimens, quenching from near $T_{B2}$ leads to an increase in martensitic temperature, whereas quenching from near $T_{L21}$ leads to an decrease in martensitic temperature.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.1
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• pp.1-11
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• 2003

Fragmentation is the main performance bottleneck of large, multi-user multicomputer system. This paper presents an L-Shaped Submesh Allocation(LSSA) strategy, which lifts the restriction on the rectangular shape formed by allocated processors in order to address the problem of fragmentation. LSSA can manipulate the shape of the required submesh to fit into the fragmented mesh system. Thus, LSSA accommodates incoming jobs faster than other strategies and results in the reduction of job response time. Extensive simulations show that LSSA performs more efficiently than other strategies in terms of the external fragmentation, the job response time and the system utilization.

• Korean Journal of Agricultural Science
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• v.31 no.1
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• pp.26-34
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• 2004

In this study, motion characteristics and power requirement of rotary tilling according to shape of conventional rotary blade were measured. This study was performed to establish factors which needed to develop energy saving rotary blade. Starting point of edged curve of imported rotary blade was faster than that of domestic rotary blade after measuring and analyzing edged curve of rotary blade. So domestic rotary blade tills much soil than imported rotary blade. In analyzing motion of rotary blade, Rotary blade of A, D type was begun to contact at part 3. Analyzing back surface of rotary blade which contact to soil at critical $\lambda$ results in contacting at e-f part. In measuring power requirement of rotary blade, specific torque and specific work of rotary blade are $160{\sim}170kgf{\cdot}m/m^2$, $3,700kgf{\cdot}m/m^3$. It shows power requirement of rotary blade according to shape of rotary blade are very different.

• Journal of electromagnetic engineering and science
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• v.14 no.2
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• pp.74-78
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• 2014

This paper presents a modified TEM horn that improves radiation characteristics at a low frequency region. The proposed antenna consists of an asymmetric TEM (ATEM) horn and a loop structure with an elliptical shape. The bandwidth and gain at low frequency region can be enhanced by using the ATEM horn configuration and adding a loop structure with an elliptical shape to the ATEM horn. The bandwidth of the proposed antenna is from 2.14 to over 20 GHz, whereas that of the conventional TEM horn is from 2.7 to over 20 GHz, where the dimensions of both antennas are the same except for the thickness of the loop structure. The physical and electrical dimensions of the proposed antenna are $60mm{\times}62.5mm{\times}64mm$ ($width{\times}height{\times}length$) and $0.428{\lambda}_L{\times}0.445{\lambda}_L{\times}0.456{\lambda}_L$, where ${\lambda}_L$ corresponds to the lowest frequency of the bandwidth. The realized gain of the proposed antenna is improved by 0.802 dB on average at the low frequency region (2 to 8 GHz), where the maximum gain increase is 2.932 dB when compared to a conventional TEM horn.

• Journal of Ginseng Research
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• v.8 no.2
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• pp.178-183
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• 1984

This study was conducted to know the influence of plant age and cultural conditions such as plant population density and light intensity under the shading on the leaf shape of panax ginseng. The result obtained were as follows; 1) Leaf length(L)/maximum width(W) was no difference with different age of over 3-over 3year old plant, but that of 1 or 2-yearold was smaller than those of over 3-year old. The values of L/W showed in the order of 2 or 4,3, 1 or 5 leaflet. 2) Ratios of leaflet area to leaf area were 32.0% in leaflet 3, from 209.% to 27.9% in leaflet 2 or 4, and from 6.5% to 7.1% in leaflet 1 or 5. 3) The coefficients of variability for L/W and ratio of leaflet area to leaf area of leaflet 3 were smallest among leaflets. 4) There were significant differences between largest and smallest leaflet 3, leaf areas and ratio of leaflet 3 area to leaf area in same plant. 5) LW and ratio of leaflet 3 area to leaf area were not affected by plant population density. 6) It showed a tendency that the L/W was increased with increasing the light transmittance rate (LTR). The ratio of leaflet 3 area to leaf area of ginseng grown under 20% LTR was not different comparing to that of plant grown under 5% LTR, but it was significantly increased in plant grown at 100% LTR.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.3
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• pp.3-8
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• 2008

In this paper, an planar antenna which has omnidirectional radiation pattern in H-plane and low profile is proposed. By adding inductance elements of an ENG shell structure, a capacitance element of an electrically small antenna is easily achieved with impedance matching. An ENG shell structure is consist of a inductive loading structure which has symmetrical four stepped L-shape slots. The simulated result shows, the impedance bandwidth of the proposed antenna is 150MHz (2.5 ~ 2.65GHz). The simulated maximum radiation gain of proposed antenna is 1.12 dBi at center frequency 2.56GHz. Omnidirectional radiation pattern is achieved. The proposed antenna will be applied to wireless lan access point system.

• Journal of the Korea Society of Computer and Information
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• v.23 no.1
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• pp.91-102
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• 2018

The purpose of this study is to develop an excellent bodice prototype that is adapted to the body shape of middle-aged women using 3D measurement data. In the evaluation of appearance, S pattern 4.00, B pattern 2.80, E pattern 2.40, L pattern 1.40 were shown in order, and the best fit of S pattern was evaluated as excellent. As a result of looking at the color distribution chart to find out the amount, E pattern and S pattern were not space in the front bust, armhole, and the back waist line. The B pattern and the L pattern were marked in blue because of insufficiency space in the back neck. As a result of evaluation the amount of air gap in the clothing, the air gap of the bust was 0.12, which is the largest pattern of B. Next, the L pattern appears as a tight circle with smallest air gap in the order of the S pattern 0.096, the E pattern 0.08, and the L pattern 0.003. The S pattern was evaluated to be the most appropriate for the body shape of middle-aged women. But the waist and back were slightly tight. Middle-aged women have larger shoulder-related items and larger waist circumference. Therefore, when you set the perimeter item, you should add 1-2cm of space amount and give extra space to the circumference area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1191-1198
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• 2015

In this paper, we develop simplified finite element (FE) models for butt-, lap- and T-welded joints by performing numerical and experimental experiments. Three-point bending tests of butt- and lap-welded specimens are performed to obtain the stiffness of the specimens and the strains at points near the welding beads. Similarly the stiffness and strains of T-welded specimen are measured by applying a point load at the end of the specimen. To develop simplified FE models, we consider the shape parameters of width, thickness and the angle of weld elements in the numerical simulations. The shape parameters of the simplified FE models are determined by building linear regression models for the experimental data sets.