• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2281-2284
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• 2014

Polystyrene beads (PS beads) with narrow size distribution were synthesized, and their diameter was controlled from 1.2 to $5{\mu}m$ by varying the injection rate of a styrene solution containing initiator and the concentration of reactant, such as initiator and capping material. The diameter of the PS beads increased with increasing in the injection rates and the initiator concentration or decreasing the capping material concentration. Then, we used the PS beads as building block, and organized them into a hexagonally close-packed monolayer on substrate with template-assisted manual assembly. We showed perfect hexagonally close-packed organization of the PS beads with various sizes in large-scale area. And we demonstrated the superiority of the dry manual assembly over the wet self-assembly in terms of simplicity, speed, perfect ordering, and large scale.

• Structural Engineering and Mechanics
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• v.54 no.5
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• pp.999-1016
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• 2015

In this paper, we introduce a new method for assembly of shipbuilding blocks at sea and present its feasibility focusing on structural safety. The core concept of this method is to assemble ship building blocks by use of bolting, gluing and welding techniques at sea without dock facilities. Due to its independence of dock facilities, shipyard construction capability could be increased considerably by the proposed method. To show the structural safety of this method, a bulk carrier and an oil tanker were employed, and we investigated the structural behavior of those ships to which the new block assembly method was applied. The ship hull models attached with connective parts are analyzed in detail through finite element analyses, and the cargo capacity of the bulk carrier is briefly discussed as well. The results of these studies show the potential for applying this new block assembly method to practical shipbuilding.

• Journal of KIBIM
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• v.12 no.1
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• pp.10-22
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• 2022

Prefabricated bridges require strict management of tolerance during fabrication and assembly. In this paper, digital engineering models for prefabricated bridge components such as deck, girder, pier, abutment are suggested to support information delivery through the life-cycle of the bridge. Rule-based modeling is used to define geometry of the members considering variable dimensions due to fabrication and assembly error. DfMA(design for manufacturing and assembly) provides the rules for ease of fabrication and assembly. The digital engineering model consists of geometry, constraints and corresponding parameters for each phase. Alignment and control points are defined to manage tolerances of the prefabricated bridge during fabrication and assembly. Quality control by digital measurement of dimensions was also considered in the model definition. A pilot bridge was defined virtually to validate the suggested digital engineering models. The digital engineering models for DfMA showed excellent potential to realize prefabricated bridges.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.31-37
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• 2011

Construction automation is yet to be improved since construction site still faces a lot of high risks and difficulties. This research focuses on applying robotic beam assembly system in place of construction workers. This system consists of CF (Construction Factory) structure to provide adequate working environment to robot automation. The CF structure not only gives automation environment for a robot but also houses the equipments to protect from outside effects. The robotic beam assembly system also consists of robotic bolting system and robot transport mechanism. It utilizes various tools to insert and join the bolts and nuts. Visual servoing helps precise robot motion by sensing bolt hole and tail of the bolt. ITA system helps non skilled workers to easily perform the assembly work with the robot system. The robot transport mechanism includes sliding rail and cross-wired lift. It carries the robot to a desired position for assembly work.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.130-132
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• 2004

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.73-80
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• 2009

This paper describes a sensor-based remote monitoring technique for ship block assembly and implementation of a prototype system. Instead of manual processing or optical measuring devices, the proposed approach attaches some distance-measuring sensor nodes to ship blocks. Remote monitoring of the assembly status makes it possible to minimize marginal errors during ship block assembly process, and helps efficient ship building.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1585-1589
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• 2007

The HANARO, a 30 MW multi-purpose research reactor in Korea, will be equipped with a neutron guide system, in order to transport cold neutrons from the neutron source to the neutron scattering instruments in the neutron guide hall near the reactor building. The neutron guide system of HANARO consists of the in-pile plug assembly with in-pile guides, the primary shutter with in-shutter guides, the neutron guides in the guide shielding room with dedicated secondary shutters, and the neutron guides connected to the instruments in the neutron guide hall. The functions of the in-pile plug assembly are to shield the reactor environment from a nuclear radiation and to support the neutron guides and maintain them precisely oriented. The primary shutter is a mechanical device to be installed just after the in-pile plug assembly, which stops neutron flux on demand. This paper describes the mechanical design of the in-pile plug assembly and the primary shutter for the neutron guide system at HANARO. The design of the guide shielding assembly for the primary shutter and the neutron guides is also presented.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.648-663
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• 2012

With recent attempts to improve quality and productivity, the prefabrication manufacturing system has been occupying an increasing share of the construction area. To minimize site work, material is more frequently being produced and partially assembled at a plant, and then installed at a site. For this reason, the production process is being divided and the materials are being delivered to the site after passing through multiple plants. With these changes in the production process, the materials delivery plan is becoming an important management point. In particular, as road transportation using trucks has a 71 percent share of the domestic transportation market, selecting the proper transportation path is important when delivering materials and equipment to a site. But the management system at the project design phase to calculate the delivery cost by considering the production process of the pre-fab material and the $CO_2$ emission at the material delivery phase is currently lacking. This study suggests a process design model for assembly production of the pre-fab material and transportation logistics based on carbon emission. The suggested model can be helpful to optimize the location of the intermediate plant. It is expected to be utilized as a basic model at the project plan and design phase when subcontractors make decisions on items such as materials procurement, selecting the production method, and choosing the location of the assembly plant.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.267.1-267.1
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• 2013

In modern science and technology, the organization of building blocks, such as spherical particles and zeolite, is important to form a nanostructure. So, it is essential to develop methods for organizing them into large scale for many precise applications. Up to now, reflux and stirring is widely used method for organization of colloidal particles. However, because this method is hard to organize building block with high coverage and uniform orientation, it is necessary to research another method. In this work, we synthesized spherical silica particles using St$\"{o}$ber method and organized them on the glass which is coated with 3-chloropropyltrimethoxysilane (CP-TMS) and polyethyleneimine (PEI) using Sonication method. Although spherical silica particles are difficult to attach on the glass due to their small attachment site, we improved this problem by coating PEI. We introduced two mode of reaction promotion, sonication (SO) and sonication with stacking between the bare glass (SS), and investigated degree of coverage (DOC) and degree of close packing (DCP).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.6-7
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• 2020

The government of South Korea enacted Earthquake Recovery Plan Act in 2008. In order to meet the requirement of this law, the important buildings, such as schools, public offices and so on, are in the process of seismic retrofit. This paper introduces the experimental data about a non-retrofitted concrete column and retrofitted column with a bolt assembly type CFT(concrete-filled steel tube).