• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.18 no.7
• /
• pp.596-602
• /
• 2006

Ice adhesion and blockage problems have been issued in continuous ice slurry making process. So we composed continuous ice slurry making device using a commercial small plate heat exchanger (PHX), and investigated character of ice formation. An experiment of ice formation was peformed with an aqueous solution of ethylene glycol 7 mass%. In the experiment, the effect of the pressurization on ice slurry formation during the cooling process was investigated. The pressurization test for the aqueous solution was performed by setting valves at the PHX inlet and outlet. At the results, the time of continuous ice formation increased as the pressure of the plate heat exchanger increased for cooling temperature of $-5^{\circ}C$. Also continuous ice formation at the cooling temperature of $-7^{\circ}C$ showed a possibility. It was found that the pressurization may contribute to suppress the dissolution of supercooled aqueous solution in the PHX.

• International conference on construction engineering and project management
• /
• 2007.03a
• /
• pp.279-288
• /
• 2007

Attempts to achieve a higher productivity have led studies to focus on process improvement. Information has been found as an essential element for process improvement. This research has introduced and focused on two types of information, namely: related jobsite information along the process and feedback information. Related jobsite information along the process which needs to be processed and delivered in a timely manner, accurate, and real time is required to streamline the decision making process. Whereas feedback information about process' current practices which have to be captured and stored is a useful for continuous improvement in identifying the problem origin and determining corrective action. In the current practices, although these two types of information are essential for process improvement, construction process has faced barriers in obtaining that information. Therefore, this research will propose a new information system to overcome the aforementioned barriers. The new information system consists of RFID as an automatic identification and data collection device integrated with database to support construction processes. The new system attempts to provide related jobsite information along the process and feedback information to support decision making process and continuous process improvement respectively. A case study of prefabrication installation process in housing projects has been selected to be implemented in conceptual model of RFID application in construction industry. Conceptual model will be presented in this paper as an initial stage of this ongoing research. Expected outcomes of the new system and future works will be discussed briefly.

• Korean Institute of Interior Design Journal
• /
• v.23 no.5
• /
• pp.76-85
• /
• 2014

When conscious and unconscious exploring information of space-visitors which is contained in the information acquired in the process of seeing any space is analyzed, it can be found what those visitors pick up as factors in the space for its selection as visual information in order to put it into action. This study, with the object of the space reproduced in three dimensions from the cafe which was visited for conversation, has analyzed the process of acquiring space-information by sex to find out the features of scanning path, findings of which are the followings. First, the rate of scanning type of males was "Combination (50.5%)- Circulation (31.0%) and that of females "Horizontal (32.5%) - Combination (32.1%)", which shows that there was a big difference by sex in the scanning path which took place in the process of observing any space. Second, when the features of continuous observation frequency by sex is looked into, the trends of increased "horizontal" scanning and decreased "Combination" scanning of both showed the same as the frequency of continuous observations increased, while in case of "Circulation" scanning, that of females was found to decrease but that of males showed the aspect of confusion. Third, the 'Combination' scanning of males was found strong at the short observation time with three times of continuous observation frequency defined as "Attention Concentration" while the distinct feature was seen that the scanning type was dispersed to "combination-circulation" as the frequency of continuous observation increased. Females start the information acquirement with "combination-circulation" but in the process of visual appreciation they showed a strong "Horizontal" These scanning features can be defined as those by sex for acquiring space information and therefore are very significant because they are fundamental studies which will enable any customized space-design by sex.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.10
• /
• pp.1254-1264
• /
• 1999

A three-dimensional coupled turbulent fluid flow and solidification process were analyzed in a continuous casting process of a steel slab with Electromagnetic Brake(EMBR). A revised low-Reynolds number $k-{\varepsilon}$ turbulence model was used to consider the turbulent effects. The enthalpy-porosity relation was employed to suppress the velocity within a mushy region. The electromagnetic field was described by Maxwell equations. Tile application of EMBR to the mold region results in the decrease of the transfer of superheat to the narrow face, the increase of temperature in free surface region and most liquid of submold region, and the higher temperature gradient near the solidifying shell. The increasing magnetic flux density effects mainly to the surface temperature of the solidifying shell of narrow face, hardly to the one of wide face. It is seen that in the presence of EMBR a thicker solidifying shell is obtained at the narrow face of the slab.

• Journal of Ocean Engineering and Technology
• /
• v.16 no.1
• /
• pp.64-70
• /
• 2002

This paper shows the results of the development of a small size of digital type continuous and intermittent welding auto-carriage based on microprocessor (Intel 80196KC) for welding process with long welding line. The developed welding auto-carriage loads welding torch and tracks welding line. It is an automaton largely used for welding process with a lot of long welding lines such as shipbuilding and structure. Most traditional auto-carriages have been developed based on analog circuit for open loop control. So this analog circuit welding auto-carriage cannon control welding speed. Specially welding auto-carriage for intermittent welding condition is so complicated and has the low precision of control performance in welding distance and non-welding distance. The auto-carriage developed in this paper has the following characteristics: It has not only functions of traditional carriage but also functions such as pseudo-welding process of big iron structures, intermittent welding in order to limit heat for welding thin plates, crater treatment of the final step of welding, acceleration at the initial step of welding and deceleration in the final step of welding. The main control board of auto-carriage, power supply system and DC motor drive wee developed and manufactured. The welding speed and the welding distance of the developed auto-carriage are controlled accurately by feedback control using photo-sensor. Hardware and software robust against the heat and noise produced on the welding process are developed.

• Korean Journal of Metals and Materials
• /
• v.46 no.7
• /
• pp.403-411
• /
• 2008

Zr-based amorphous alloy matrix composites reinforced with tantalum continuous fibers were fabricated by liquid pressing process, and their microstructures and mechanical properties were investigated. About 60 vol.% of tantalum fibers were homogeneously distributed inside the amorphous matrix, which contained a small amount of polygonal crystalline particles. The ductility of the tantalum-continuous-fiber-reinforced composite under tensile or compressive loading was dramatically improved over that of the monolithic amorphous alloy, while maintaining high strength. The consequential observation of the tensile deformation and fracture behavior of the composite showed the formation of multiple shear bands and multiple necking, crack deflection in the amorphous matrix, and obstruction of crack propagation by ductile fibers, thereby resulting in very high tensile elongation of 7.2%. These findings suggested that the liquid pressing process was useful for the development of amorphous matrix composites with improved ductility.

• 한국생물공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.243-245
• /
• 2003

The continuous fermentation process for exe-biopolymer production with Cordyceps militaris has been developed in this research. With the change of dilution rate, biopolymer production has been changed and the maximal biopolymer production has been achieved when the dilution rate was 0.0225/hr. The maximum mycelium concentration and biopolymer concentration were 8 g/L and 4.2 g/L, respectively.

• Journal of Korean Society on Water Environment
• /
• v.23 no.5
• /
• pp.577-580
• /
• 2007

The influence of flow rate has been investigated on the treatment efficiency of continuous cycling electrolytic process employing artificial and actual photographic wastewater which containing silver ion. For artificial wastewater, the treatment efficiency of process was found to rise ca. three times when the flow rate of wastewater was increased from 3 mL/min to 15 mL/min. The process efficiency was doubled under the same condition regarding actual wastewater. The effect of flow rate on the treatment efficiency was observed to be altered according to the metal ionic form and solution composition. The coefficient of mass transfer was estimated using model equation, which verified that the raised treatment efficiency at higher flow rate was due to the increased mobility of ionic species.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.616-619
• /
• 1996

This paper presents the configuration methodology of Distributed Control System(DCS)s for process plant and their performance evaluation. Performance evaluation is specified both in terms of operational and installation aspects of system. In order to evaluate performance criteria of operational aspect, a simulation method is proposed. Modeling of system components including process computer, database, process controllers and LANs, etc, is implemented for simulation. Based on these characteristics, different system configurations are evaluated and compared through results about evaluation criteria in order to select the best DCS for particular process. The results, in abbreviated form, of the performance evaluation of DCS controlling a CAL(Continuous Annealing Line) plant of iron process are presented.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.13 no.3
• /
• pp.237-244
• /
• 2013

A continuous, explicit drain-current equation for short-channel double-gate (DG) MOSFETs has been derived based on the explicit surface potential equation. The model is physically derived from Poisson's equation in each region of operation and adopted in the unified regional approach. The proposed model has been verified with numerical solutions, physically scalable with channel length and gate/oxide materials as well as oxide/channel thicknesses.