• Journal of Practical Engineering Education
• /
• v.7 no.2
• /
• pp.119-123
• /
• 2015

ABS material is easy to process, impact resistance and heat resistance is strong. ABS material is often used as a substitute for the interior and exterior metal material for an automobile. As the demand of ABS increases, fabricating education using ABS has also been increasing its importance. As part of its education, ABS material is used in the mold fabricating part of the regional and national skills competition. At this time, the force of the vise for fixing the ABS material in the processing using the ABS material can affect the final shape after machining. However, it has not been an accurate description of the notes and instructions of working in education. Therefore, in this study, we study the impact the force of vise affect structural shape in the fabricating education using ABS material and during fabricating education of ABS material, trying to present the notes of the appropriate it.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.6
• /
• pp.537-543
• /
• 2020

The window cleaning works are manpower-dependent and are performed in an unstable posture at high altitude, so that there is a risk of falling. Therefore, there is an urgent need to improve the safety of workers. In this study, a conceptual design was proposed for the cleaning of exterior windows of a building, and the economic feasibility of the proposed conceptual model was analyzed. The proposed model is designed to avoid protrusions such as window frames, and to be able to respond even if the shapes of the upper and lower parts are different. As a result of analyzing the economic feasibility of the designed conceptual model, the benefit cost ratio was 4.48, which was significantly higher than 1. Therefore, the economic feasibility of the proposed window cleaning device is expected to be sufficient. The results analyzed in this paper will be used in the development and marketing of the window cleaning device.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.26 no.6
• /
• pp.821-832
• /
• 2002

The purpose of this study was to develop grading method of the basic brassiere patterns therewith, provide for 12 size's brassiere patterns and prove fitness of their's and shape. The collected data were statistically processed using the SAS 6.12 for Means, Standard Deviation, etc. The results of this study can be summarized as follows; 1. The basic sizes adopted at the first design stage (see fig.1-2) were 75AA, 75A and 75B each of which was designed as upper foundation basic pattern in reference to the cup size. At the second stage, each of the upper body foundation basic pattern was used to design lower cup, upper up, front panel and wing in their order(see fig.3-6). At the third stage, the other sizes were graded in reference to the three brassiere patterns (75AA, 75A and 75B) to produce 12 brassiere sizes(see Tab. 7-8). In order to develop the basic patterns of adult women's brassieres, 33 women were selected per 11 size combination(3 women per size combination), and then, their brassiere fitting was teated. As a result, the fronts of the basic patterns were found to have such problems as undone front center, poor levelling of upper cup's bottom line or lower cup's top line, poor shape of upper cup's outside top line and shoulder strip position. On the other hand, on the rear side of the basic patterns, the central part of the wing was slightly lifted, while the wing width and straps'interval did not befit the ful1-cup brassiere. The result of this first brassiere fitting test showed that the functionality and aesthetics of the basic pattern brassieres were more or less satisfactory, and thus, the problems were addressed for the second teat. In the second test, the aesthetics, breast-shaping effect and functionality of the basic pattern brassieres were much improved. 2. We were to present the final brassiere sizing system to extend the interior length of breast and the exterior length of breast on the basis of fitting test. Thereby, 75B$.$80A$.$80B$.$85A$.$85B's the interior lengths of breast were enlarged to 0.7cm, the rest size was enlarged to 0.5cm and the exterior length of breast was enlarged to 0.5cm regardless of sizes. 3. The upper foundation basic patterns of 75AA and 75B were presented and and the basic brassiere pattern and grading pattern were presented through to.

• Journal of the Korea Institute of Building Construction
• /
• v.16 no.1
• /
• pp.9-15
• /
• 2016

The part of a building with the biggest energy loss is the exterior and many studies are actively conducted to reduce the energy loss on that part. However, most studies consider the window frames and insulation materials, but many studies do not discuss the concrete that takes more than 70% of the exterior. In order to minimize the energy loss of buildings, it is necessary to enhance the concrete's insulation performance and studies need to be conducted on this. Therefore, this study used a micro foam cell admixture, calcined diatomite powder, and lightweight aggregates as a part of a study to develop a type of concrete with improved insulation performance that has twice higher thermal conductivity compared to concrete. It particularly secured the porosity inside concrete to lower thermal conductivity. As a result of the experiment, the slump and air capacity showed fair results, but all mixtures containing micro foaming agent showed 14.3~35.1% lower mass per unit of volume compared to regular concrete. Compressive strength decreased slightly due to the materials used to improve the insulating performance, but it all satisfied this study's target strength(24MPa). Thermal conductivity was up to twice higher than that of regular concrete.

• Korean Journal of Construction Engineering and Management
• /
• v.10 no.6
• /
• pp.3-12
• /
• 2009

In order to effectively distribute the resources, it is very critical to understand the status or progress of construction site quickly and accurately. Augmented Reality (AR) can provide this situation with information which is convenient and intuitive. Conventional implementation of AR in outdoor or construction site condition requires additional sensors or markers to track the position and direction of camera. This research is aimed to develop the technologies which can be utilized in gathering the information of constructing or constructed buildings and structures. The AR technique that does not require additional devices except for the camera was implemented to simplify the system and improve utility in inaccessible area. In order to do so, the position of camera's perspective center and direction of camera was estimated using exterior orientation techniques. And 3D drawing model of building was projected and overlapped using this information. The result shows that by using this technique, the virtual drawing image was registered on real image with few pixels of error. The technique and procedure introduced in this paper simplifies the hardware organization of AR system that makes it easier for the AR technology to be utilized with ease in construction site. Moreover, this technique will help the AR to be utilized even in inaccessible areas. In addition to this, it is expected that combining this technique and 4D CAD technology can provide the project manager with more intuitive and comprehensive information that simplifies the monitoring work of construction progress and planning.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.2
• /
• pp.267-272
• /
• 2021

In this study, the output results of 3D printed exterior materials for application to buildings of various shapes are output tests using test specimens, in which 3D printing concrete is cast in a mold and accelerating agents are used to ensure stackability. The unit weight and strength characteristics of the body were analyzed. Compared to the unit weight of concrete placed in the mold, the unit weight of 3D printing concrete using accelerating agents tends to decrease by approximately 3.5% to 5.0%, and the compressive strength is the compressive strength of the concrete placed in the mold. In comparison, the compression strength of the output by 3D printing tended to decrease by approximately 36% to 46%. In the flexural strength, the compressive strength of the output through 3D printing decreased by approximately 36% to 46% compared to the compressive strength of concrete placed in the mold. The impact on the strength characteristics of 3D printed concrete using accelerating agents tended to decrease by approximately 2.0 to 5.8%. Therefore, 3D printing output accelerating agents can be used.

• Journal of Korea Water Resources Association
• /
• v.56 no.7
• /
• pp.461-470
• /
• 2023

The purpose of this research is to derive the optimal temperature, location, and heating control system for a tipping bucket rain gauge heating system used for observing snowfall during winter. We conducted indoor and outdoor experiments by manufacturing a tipping bucket rain gauge that can be variably controlled for heating at the funnel, exterior, and interior, and indoor and outdoor. The indoor experiments involved using a temperature and humidity chamber to compare the performance and derive the appropriate temperature of the precipitation gauge heating system. Subsequently, the outdoor experiments were carried out at the Cloud Physics Observation Center located in Daeguallyeong, heavy snowfall region, to validate the findings. The analysis result was derived that the heating temperature of the funnel should be set at the 10 to 30℃, while the internal heating temperature should be 70℃. Furthermore, the optimal locations for the heating devices, which aim to minimize measurement delay, were identified as the exterior of the rain gauge, the rim of the funnel, and the vertical surface of the funnel. Our result shows that used as the basis for the operating conditions of precipitation gauge heating systems for solid precipitation measurement in winter.

• Journal of the Microelectronics and Packaging Society
• /
• v.22 no.3
• /
• pp.51-56
• /
• 2015

It has been used various pad finish materials to enhance the reliability of solder joint and recently Electroless Ni Electroless Pd Immersion Gold (the following : ENEPIG) pad has been used more than others. This study is about reliability according to being used in commercial Electrolytic Ni pad and ENEPIG pad, and was observed behavior of various Cu contents. After reflow, the inter-metallic compound (IMC) between solder and pad is composed of $Cu_6Sn_5$ (Ni substituted) by using EDS, and in case of ENEPIG, between IMC and Ni layer was observed the dark layer ($Ni_3P$ layer). Additional, it could be controlled the thickness of dark layer according to Cu contents. Investigated the different fracture mode between electrolytic Ni and ENEPIG pad after drop shock test, in case of soft Ni, accelerated stress propagated along the interface between $1^{st}$ IMC and $2^{nd}$ IMC, and in case of ENEPIG pad, accelerated stress propagated along the weaken surface such as dark layer. The unstable interface exists through IMC, pad material and solder bulk by the lattice mismatch, so that the thermal and physical stress due to the continuous exterior impact is transferred to the IMC interface. Therefore, it is strongly requested to control solder morphology, IMC shape and thickness to improve the solder reliability.

• Journal of Korean Society of Steel Construction
• /
• v.26 no.4
• /
• pp.299-309
• /
• 2014

HSA800 is a new high strength steel (HSS) plate for building structures developed by POSCO and RIST in 2011. It has upper and lower bounds for yield ($F_y$) and tensile ($F_u$) strength as of 650-770MPa and 800-950MPa, respectively, with yield ratio ($F_y/F_u$) limit as of 0.85 which make steel quality more reliable and enhance the seismic resistance of structures. As made by TMCP, it has a good weldability without increasing carbon percentage. The objective of this study is to provide alternative design of mega-structural members of the Lotte World Tower (555m, 123 story), a first super-tall building in Korea, using HSS considering structural safety, constructability, and cost-effectiveness. Steel outrigger trusses, belt-trusses and steel exterior columns were selected and analyzed to evaluate the structural performance between original and alternative designs using HSS. The results show that HSS can be applied to the members which do not affect lateral stiffness of a building and, in this study, approximately 1100tons of steel were saved. It implies that HSS can save overall construction costs - manufacturing, delivery, and erection costs - by reducing mega structural member size. HSA800 was very first applied to the Lotte World Tower based on the results of this study.

• Journal of the Korean Institute of Gas
• /
• v.24 no.4
• /
• pp.18-24
• /
• 2020

The purpose of this study is to validate thermal hinderance effects, i.e., feasibilities, of fire-proof structure for LPG tank exposed to fire from adjacent burning building. The panel materials suggested for the fire-proof structure are (1) 10 mm-thick wood, (2) wood with fireproof coating, (3) 75 mm-thick Expanded Polystyrene, (4) 75 mm-thick glass wool filled sandwich panel, and (5) 75 mm-thick autoclaved lightweight concrete. The square planar fire source of 1 ㎡, a matrix of nozzles releasing 120-140 g/s of LPG, is used to heat up the wall and the tank beyond, mimicking heat transfer from burning exterior wall finishes. The feasibility is tested by inspecting structural integrity after test, and then by examining temperatures at both sides of panels and tank's front surface as well as heat fluxes. As a result, it can be concluded that, among the suggested sample materials, fire-proof wall with ALC panel only showed the feasibility for explosion prevention with the proven evidences of structural integrity and least increase in temperature of tank.