• Journal of Ocean Engineering and Technology
• /
• v.16 no.1
• /
• pp.41-45
• /
• 2002

This paper is concerned with the erection and ultimate load test of dome shaped space structures by post-tensioning. It is a fast and economical method for constructing such a dome by post-tensioning of the cable in bottom chords. This structure consists of uniform pyramids in a flat layouts on the ground, and then the structure is shaped and erected into its final curved space structure. Ultimate load test was performed for dome shaped space structures. The feasibility of the proposed erection method and the reliability of the established geometric model were confirmed with numerical analysis and experimental investigation on a small scale steel model. As a results we can find the most reasonable modeling technique for the prediction of shape formation in practices and we can know the characteristic of the behaviour in ultimate load test for practical design purposes.

• Journal of architectural history
• /
• v.31 no.1
• /
• pp.51-60
• /
• 2022

In the 16~17th centuries, the construction of T-shaped pavilion in Gyeongsangbuk-do was centered on the families of the Goseong-Lee clan and Andong-Kwon clan, who had a lot of exchanges with each other near Andong. It can be presumed that the complex structure of the T-shaped pavilion was intended to represent the technology, economic power, and social influence of the clan. After the 18th century, construction areas spread and construction subjects were diversified, but the number of new constructions decreased. It can be seen that T-shaped pavilion was erected and used for public purposes rather than personal reasons in terms of layout or flat scale. The roof of the T-shaped pavilion is very diverse depending on the wooden structure, the height of the roof and the configuration of the apex. The T-shaped pavilion, which combines two parts, has been developed in a way that strengthens not only the appearance but also the structural bonding force. The bonding strength is strengthened through the process of "roof aligning", "roof bonding", "structure connection", and "structure integration", which shows a similar tendency to the age of actual cases.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.23 no.1
• /
• pp.52-55
• /
• 2012

Background and Objectives : Based on histological findings, intracordal cysts are divided in two subtypes : retention cysts and epidermoid cysts. They are typically located in the superficial layer of the lamina propria and appeared as opaque ovoid buldging masses underlying the epithelium. They are characterized by unilateral diminished mucosal wave on stroboscopy. In this article, we report some cases of patients with an oval shaped-yellowish flat cyst. Materials and Method : At the clinic of the department of otorhinolaryngology in Gangnam Severance Hospital, with 3 female complained of hoarseness as subjects, using the stroboscopy we checked preoperative and postoperative vocal cord and operative findings. Surgery was performed under general anesthesia by the senior authors. All patients noted subjectively that their performing voice was improved. Results : During surgery, an oval shaped-yellowish flat cystic lesion was distinguished from normal epithelium. On palpation of this area with microforceps and cottons, the yellowish discharge was noted to move out from the opening of the cyst. In one case, the cyst was ruptured but remove the capsule completely. In other cases, sulcus was noted at the oppsite site. Conclusion : Because of the opening, the cyst was not easy to dissect and remove completely. After the debris was move out, fibrosis around the opening and invaginated epithelium extending into the deeper layers to the fold. The cyst was must removed carefully and completely for improvement of voice quality before evolving into a sulcus vocalis.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.33 no.6
• /
• pp.391-399
• /
• 2020

In this study, the behaviors of a suction cap shaped as an arch were analyzed using finite element models. The fundamental structural behaviors of both flat- and arch-type caps were compared, and the advantages of the arch-shaped cap were explained. Moreover, the effects of geometric parameters and stiffener arrangements on the stress and deformation of the arch-shaped caps were investigated by comparisons of the changes in the behaviors of the caps. Additionally, the effects of boundary condition at the edge of the cap were analyzed to study the interactions between the cap and cofferdam walls; these results were used to derive the fundamental structural design of stiffened arch caps. Unlike flat caps, the results showed that ring stiffeners could improve the structural behaviors of arch caps remarkably, while the contributions of the radial stiffeners to the structural behaviors of the caps are dependent on constraints at the edges of the caps.

• Wind and Structures
• /
• v.19 no.2
• /
• pp.113-144
• /
• 2014

Separation bubble and conical vortices on a large-span flat roof were observed in this study through the use of flow visualization. The results indicated that separation bubble occurred when the flow was normal to the leading edge of the flat roof. Conical vortices that occur under the cornering flow were observed near the leading edge, and their appearance was influenced by the wind angle. When the wind changed from along the diagonal to deviating from the diagonal of the roof, the conical vortex close to the approaching flow changed from circular to be more oblong shaped. Based on the measured velocities in the conical vortices by flow visualization, a proposed two-dimensional vortex model was improved and validated by simplifying the velocity profile between the vortex and the potential flow region. Through measured velocities and parameters of vortices, the intensities of conical vortices and separation bubble on a large-span flat roof under different wind directions were provided. The quasi-steady theory was corrected by including the effect of vortices. With this improved two-dimensional vortex model and the corrected quasi-steady theory, the mean and peak suction beneath the cores of the conical vortices and separation bubble can be predicted, and these were verified by measured pressures on a larger-scale model of the flat roof.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.48 no.3
• /
• pp.417-432
• /
• 2024

This study aimed to enhance the comfort of health masks by conducting in-depth interviews, online surveys, and wearing tests on commercial health masks. The findings are summarized below. In-depth interviews revealed that the most comfortable mask styles were ranked as follows: Beak-1 (B-1) & Beak-2 (B-2) style > Flat style > 3-Horizontal foldable (3H) style. Men generally preferred flat style masks, while women favored beak-shaped masks. The internet survey results showed that 77.8% of surveyed brands offered a variety of mask styles, with 3H and B-2 masks being the most common. Different brands provided masks with different filtration levels, ranging from KF-AD to KF94. Size consistency also varied among brands, with flat masks having relatively consistent dimensions and B-2 masks showing significant size differences. Wearing tests indicated that 3H and B-1 masks were highly satisfying for categories like "itchiness," "unpleasant odor," and "mask slipping." Conversely, flat masks scored the highest satisfaction in classifications such as "stiff," "heavy," "thick," "hot while wearing it," "moisture accumulation," "breathing discomfort," "short ear straps," and "itchiness". Overall, the flat style, B-1, and B-2 yielded higher satisfaction levels, while 4-Horizontal foldable (4H) and 3H garnered lower satisfaction scores on wearing tests.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.220-224
• /
• 2005

The technology trend of Flat Panel Display (FPD) equipments have been demanded that there are compact and multi-function. Therefore, nano/micro scale patterned on polymeric materials of Back Light Unit (BLU) in Liquid Crystal Display (LCD) that has been investigated. This paper describes a series of Horizontal Type Micro Tensile Tester that were carried out to investigate the load strain distance performance of typical polymeric material sheets. The polymeric materials film that micro size shaped specimens for tensile test are used by Cold-Isostatic-Press (CIP). Test equipment is Horizontal type Micro Tensile Tester that is presented to measure the micro scale mechanical property of thin film for FPD. This paper presents which easy testing tools measure for micro patterned on polyethylene (PET) specimens.

• Advances in concrete construction
• /
• v.5 no.2
• /
• pp.173-182
• /
• 2017

This paper is aimed at determining the shear and impact strength of waste plastic fibre reinforced concrete. M30 grade of concrete is prepared with waste plastic door fibres cut into 5 mm width and aspect ratios of 30, 50, 70, 90 and 110. Fibres are used in a volume fraction of 0 to 1.5% with an increment of 0.25%. L shaped specimens are cast for shear strength tests and flat plates of size $250{\times}250{\times}30mm$ are used for impact tests. "Drop ball method" is used for checking the impact strength. Shear strength is checked with L shaped specimens under UTM with a special attachment. It was found that up to 1.25% of waste plastic fibres can be effectively used for better strength of concrete both in shear and impact. Shear and impact strength were found to be increasing up to a volume fraction of fibres of 1.25%.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2000.10a
• /
• pp.204-209
• /
• 2000

This paper suggests that post-tensioned and dome-shaped space truss formed by post-tersionong is easy to fabricate in construction process. In particular, a laboratory model is used to show how a flat space truss system can be transformed into a dome-shaped space truss by means of post-tensioning. There are some diserpancy in vertical displacement of the dxperiment and theoretical analysis for space truss. Nonlinear analysis is used to predict the final shape shape of the space truss, the experiments tndicates that this construction method can offer economy over traditional methods. In addition, the analysis indicates that when all the sxisting mechanisms are controlled, the nonlinear finite element method is more reliable way to predict the shape of the dome-shaped space truss than the linear analysis.

• Journal of Korean Society of Steel Construction
• /
• v.15 no.4 s.65
• /
• pp.403-412
• /
• 2003

The composite metal deck plate system has been widely used for office structures. Recently, however, the flat deck plate has been developed to apply the composite slab system to residential structures. Reduction in construction cost and time can be expected by using expanded metal instead of wire mesh as crack control reinforcements. This study proposed a composite slab system composed of a new-shaped steel deck plate and expanded metal. Twelve specimens were tested to evaluate the structural performance of the new composite slab system. The test results were summarized mainly in terms of maximum load carrying capacity and failure behaviors of each specimen.