• Journal of the Korean Society of Clothing and Textiles
• /
• v.16 no.4 s.44
• /
• pp.485-493
• /
• 1992

Three kinds of tight skirts, slim type, straight type, and semi-tight type were investigated to obtain necessary information about the size of the back slit. Fourteen college students put on these experimental clothes and walked on the flat floor, going up and down the stairs. The dimensions of the back slit were measured by width and length. The stride length was taken from the record of footprints of walking. The correlation between the body measurement, stride length and the size of the back slit was studied. As a result of this experiment, the findings are as follows: 1. The size of the back slits differed from each skirt type at the level of p<0.001. In the case of walking on the floor, the average dimension of the back slit was 14.0 cm long 5.0 cm wide for the slim type,9.5 cm long 2.8 cm wide for the straight type and 2.1 cm long 0.5 cm wide for the semi-tight type. 2. In the case of walking on the stairways, the average dimension of the back slit was 16.0 cm long 5.8 cm wide for the slim type, 12.4 cm long 3.9 cm wide for the straight type and 3.1 cm long 1.1 cm wide for the semi-tight type. 3. The correlation between the height (stature, waist height, knee height) and the size of back slit was 0.3 to 0.6. The correlation between the girth (waist, hip) and the size of back slit was 0.3 to -0.5. 4. The correlation between the stride length and the size of back slit was 0.76 for the slim skirt, 0.56 for the straight skirt, 0.28 for the semitight skirt.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1996.06c
• /
• pp.977-986
• /
• 1996

The uncertainty of rains at the onset of wet season (WS) and the drought risk involved hinder growing more than one rainfed lwoland rice crop per year. Establishing transplanted rice well into the WS leaves insufficient moisture in the soil for subsequent crop. Rice establishment early in the season gives the farmer better opportunities to grow a crop after rice. An experiment was conducted startign in 1993 to evaluate dry seeding of rice through slit soil seeding. It is done utilizing the vertical metering slit seeder for conserving soil moisture coming from the first rains in the early WS to sustain germination and establishment of the seeding at least until the succeeding rains under therainfed lowland (RL) environment. The treatment consisted of slit-seeding the PSBRc 14 into the tilled and nontilled plots at 100kg/ha and at depths of <10 mm (shallow seeding) and 60-70m (deep seeding). The control treatment was broadcast seeded on tilled soil and harrow to cover the seeds The superior crop establishment observed in 1995 WS experiment on nontilled, slit-seeded plots confirmed the results observed in 1993 WS and 1994 WS experiments. Emergence in deep seeding was not significantly different from shallow seeding in nontilled plots giving an average yield of 2.1 t/ha in all slit-seeded plots. This offers an advantage of reduced energy in put in nontilled shallow seeding. However, heavy weed infestation has to be addressed at the early stage of rice in nontilled soil to get the full advantage from slit seeding. The consistently better crop establishment observed in slit seeding over that of broadcast seeding in the WS of 1993, 1994 and 1995 also demonstrates that the slit seeding technology can be adopted with confidence in the rainfed lowland field condition to reduce the risks involved in broadcast seeding.

• Steel and Composite Structures
• /
• v.32 no.1
• /
• pp.79-90
• /
• 2019

This study introduces new connections that connect the beam to the column with slit dampers. Plastic deformations and damages concentrate on slit dampers. The slit dampers prevent plastic damages of column, beam, welds and panel zone and act as fuses. The slit dampers were prepared with IPE profiles that had some holes in the webs. In this paper, two experimental specimens were made. In first specimen (SDC1), just one slit damper connected the beam to the column and one IPE profile with no holes connected the bottom flange of the beam to the column. The second specimen (SDC2) had two similar dampers which connected the top and bottom flange of the beam to the column. Cyclic loading was applied on Specimens. The cyclic displacements conditions continued until 0.06 radian rotation of connection. The experimental observations showed that the bending moment of specimen SDC2 increased until 0.04 story drift. In specimen SDC1, the bending moment decreases after 0.03 story drift. Test results indicate the high performance of the proposed connection. Based on the results, the specimen with two slit damper (SDC2) has higher seismic performance and dissipates more energy in loading process than specimen SDC1. Theoretical formulas were extended for the proposed connections. Numerical studies have been done by ABAQUS software. The theoretical and numerical results had good agreements with the experimental data. Based on the experimental and numerical investigations, the high ductility of connection is obtained from plastic damages of slit dampers. The most flexural moment of specimen SDC1 occurred at 3% story drift and this value was 1.4 times the plastic moment of the beam section. This parameter for SDC2 was 1.73 times the plastic moment of the beam section and occurred at 4% story drift. The dissipated energy ratio of SDC2 to SDC1 is equal to 1.51.

• Journal of Korean Society of Water and Wastewater
• /
• v.32 no.6
• /
• pp.479-485
• /
• 2018

Large amounts of oily wastewater discharged from various industrial operations (petroleum refining, machinery industries and chemical industries) cause serious pollution in the aquatic environment. Although dissolved air flotation (DAF) separating oil pollutants using microbubbles represents current practice, bubble size cannot be selectively controlled, and lots of power is required to generate microbubbles. Therefore, to investigate performance of the DAF process, this study examined the distribution of different sizes of microbubbles resulting from changes in physical shear force via modifying shapes of a slit-nozzle without an additional power supply. Three types of slit-nozzles (different angle, shape and length of the slit-nozzle) were used to analyze the distribution of bubble size. At a slit angle of $60^{\circ}$, shear force was 4.29 times higher than a conventional slit, and particle size distribution (PSD) in the range between 2 and $20{\mu}m$ more than doubled. Treatment efficiency of synthetic oily wastewater through the coagulation-DAF process achieved 90% removal of COD by injecting $FeCl_3$ and PACl of 250 mg/L and 100 mg/L, respectively, and the same performance resulted using $FeCl_3$ of 200 mg/L and PACl of 80 mg/L employing a slit-nozzle angle of $60^{\circ}$. This study shows that a coagulation-DAF process using a modified slit-nozzle can improve the pre-treatment of oily wastewater.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.5
• /
• pp.1202-1207
• /
• 1993

An optical method of slit beam scanning topography is presented for the 3-dimensional profile measurement of free-formed surfaces. A slit beam of laser is projected in a scanning mode and its illuminated trajectory on the object is captured by using a CCD camera. The 3-dimensional coordinates of the trajectory is then computed by using the given geometry between the slit beam and the camera, so that the whole surface profile of the object can be obtained in a successive manner. Detailed optical principles are described with special emphasis to lateral are discussed to demonstrate the measuring performances of the slit beam scanning topography proposed in this study.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.3
• /
• pp.670-679
• /
• 1995

This paper presents the 3-D profile measurement system of live human faces, which was developed specially for 'KUMDORI sculptor robot' of the '93 Taejon Exposition. '93 Taejon EXPO. The basic principle for measurement adopts the slit beam projection which is a method of measuring 3-D surface profiles using geometric optics between the slit beam and the CCD camera. Since the slit beam projection consumes long measuring time, it is unfit to measure the 3-D profiles of living objects as human. Therefore, the projection type slit beam method which consumes short measuring time is newly suggested. And an algorithm to reconstruct the 3-D profile from the deformed images using finite approximated calibration is suggested and practically implemented. The projection type slit beam method was applied to spectators in a period of '93 Taejon EXPO. The measurement results show that the technique is suitable for 3-D face profile measurement on a living body.

• Design & Manufacturing
• /
• v.10 no.2
• /
• pp.6-11
• /
• 2016

Designed patterns of slit are introduced to the uni-directional (UD) prepreg in order to enhance the formability of the carbon/epoxy composites without wrinkling and laddering. Three different types of the slit alignment along the thickness direction are applied to analyse the deformation behavior during the compression moulding process of laminates. Degrees of the slit open and the mechanical strength are evaluated based on the level of the compaction pressure in the course of forming process. Results have shown that the mechanical strength of laminates having slits could attain at least 80% of the conventional ones without slits. However, further studies are required to identify the direct relevance of the slit alignment in laminate to the mechanical properties.

• Steel and Composite Structures
• /
• v.51 no.1
• /
• pp.93-101
• /
• 2024

This paper presents an experimental and analytical study on a steel slit damper designed as an energy dissipative device for earthquake protection of structures considering soil-structure interaction. The steel slit damper is made of a steel plate with a number of slits cut out of it. The slit damper has an advantage as a seismic energy dissipation device in that the stiffness and the yield force of the damper can be easily controlled by changing the number and size of the vertical strips. Cyclic loading tests of the slit damper are carried out to verify its energy dissipation capability, and an analytical model is developed validated based on the test results. The seismic performance of a case study building is then assessed using nonlinear dynamic analysis with and without soil-structure interaction. The soil-structure system turns out to show larger seismic responses and thus seismic retrofit is required to satisfy a predefined performance limit state. The developed slit dampers are employed as a seismic energy dissipation device for retrofitting the case study structure taking into account the soil-structure interaction. The seismic performance evaluation of the model structure shows that the device works stably and dissipates significant amount of seismic energy during earthquake excitations, and is effective in lowering the seismic response of structures standing on soft soil.

• 한국방재학회:학술대회논문집
• /
• 2007.02a
• /
• pp.159-162
• /
• 2007

The numerical efforts are presented for investigation of irregular waves passing a slit cassion and a warock block breakwater. In the numerical model, the Reynolds equations are solved by a finite difference method and $k-\varepsilon$ model is employed for the turbulence analysis. To track the free surface displacement, the volume of fluid method(VOF) is employed. Numerical predictions of reflection and transmission coefficients are compared with those of the warock block breakwater with the slit caisson. Energy dissipation and seawater exchange rates of the slit caisson are better than those of the warock block breakwater.

• Journal of the Semiconductor & Display Technology
• /
• v.3 no.3
• /
• pp.37-40
• /
• 2004

This study presents numerical solutions of three-dimensional laminar flow-field formed by photo resist flow in a slit-coater model. We discuss on the governing equations, laminar viscosities and the computational model applied in our numerical calculation and some results. We prove that the structure of tapered-cavity aid to make uniform pressure-field and boundary effect is an important problem to improve coating uniformity. In view of uniformity improvement, it is necessary to study for the structure of cavity and flow path.