• 대한기계학회논문집B
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• 제24권8호
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• pp.1085-1096
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• 2000

An experimental study was performed to examine the heat and mass transfer characteristics of $LiBr-H_2O$ solution flowing over a single horizontal tube with the water vapor absorption. Effects of the flow rate and the temperature of the solution at the top of the tube, the absorber pressure and the drainage pattern were considered. The absorption rate depends highly on the absorber pressure at the low flow rate condition while on the solution inlet temperature at the high flow rate condition. Also, when the flow rate is low, the absorption performance with the sheet flow drainage appeared to be higher than that with the dripping/jet drainage. However, at the high flow rate condition, the case became reversed. The liquid film became wavy with the higher absorption rate. The waves were more probable to form with the lower flow rate and temperature of the solution, and with the higher absorber pressure.

• 복식문화연구
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• 제9권6호
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• pp.855-871
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• 2001

The purposes of this study were to compare the marketing compose elements of Apgujung and Shinchon branch of Hyundai Department Store and to suggest desirable fashion marketing strategies for other Department Stores and retailing stores. The results were as follows: Two kinds of factor were classified form this study; one was Hardware elements such as Trading Area Site, Store Composition, Scale, and Subsidiary facilities etc., another was Software elements like Store Concept, Image, and Merchandising and so on. The followings were suggested from Hardware elements; 1) Trading Area could be classified'local type'and 'spread type'. 2) Each branch was differentiated from store formation of conventional department store which had food department in basement. There were the most powerful women's fashion brand to lead costumers in second basement. 3) In accordance with the position of subsidiary facilities of Hyundai Department Store,'Water Jet Effect'strategy and'Show Effect'strategy could be usefully applied for other Department Stores and retailing stores. 4) The strategy of approaching easily to the target floor which was located in lower floor, could be applied to various retailing stores. The followings were suggested from Software elements; 1) Stores management coping with poles-apart in costumer could be needed to other Department Store and retailing stores. 2) It also could be needed to find and maintain effective ratio between common brand and differentiated brands in the other Department Stores.

• 한국가시화정보학회지
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• 제13권1호
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• pp.49-53
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• 2015

Recently, researches for droplet impact phenomena have been faced a new phase in the direction of studying the effect of complex external conditions (e.g. wettability, temperature, morphology, electric field, etc.) for depth understanding and precise controlling in various applications. Hence, here we investigated the electrified droplet impact phenomena, because there were few quantitative researches for electrified droplet impact when we considering many real applications such as electrospray, electrohydrodynamic (EHD) jet printing. To observe interaction effect of surface charge between substrate and droplet simultaneously, micro-droplets with various Reynolds number (Re) and Weber number (We) were dripped on super-hydrophobic surface with existence and nonexistence of electrical surface charge. It shows three kinds of impact behaviors, fully bouncing, partial bouncing, and splashing with different We. Also, charged droplet bounced higher on electrically charged surface than on non-charged surface. Additionally, transition regions of three impact behaviors were classified quantitatively with water hammer pressure value, which means instant pressure inside droplet at the impact moment.

• 펄프종이기술
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• 제45권4호
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• pp.21-26
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• 2013

The effect of esterified starch as surface sizing agent for inkjet printing paper has been evaluated and compared with oxidized starch. Also the influence of various additives including cationic poly-DADMAC, stearic acrylic copolymer, calcium chloride, and GCC was examined. Results showed that starch ester gave higher ink density than oxidized starch. Addition of poly-DADMAC improved water fastness. In general, low molecular weight poly-DADMAC performed better than high molecular weight one, and it was attributed to the fact that it gave more uniform film forming characteristics in surface sizing. Use of styrene acrylic acid copolymer increased hydrophobicity of the paper surface, but it did not increase the ink density. Use of GCC and calcium chloride had only marginal effect on printing quality.

• 수산해양기술연구
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• 제53권4호
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• pp.327-336
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• 2017

Fishing dredge in Jeollabuk-do began to become widespread in the 1960s and has continued to catch diverse kinds of shellfish in the productive fishing grounds around Dongjin River, Mangyeong River and Geum River estuaries. Since the 1970s, the construction of various large-scale industrial complex and the implementation of Saemangeum reclamation project have resulted in a decrease in main fishing areas and a sharp decline in shellfish production. As a result, dredge fishery has faced many difficulties. Dredge fishery in Jeollabuk-do is carried out with a total of 30 fishing permits as of 2016. Surf clams, hen clams, bladder moon snails, and common orient clams were mainly caught before the construction of Saemangeum dike while comb pen shells, purple whelks and ark shells are mainly caught afterwards. Inside the Saemangeum dike, most fish species have disappeared due to low water level and low salinity, and littleneck clams are caught using a jet pump type of fishing dredge. Outside the dike, the diversity of shellfish species has been reduced; comb pen shells are mainly caught. In this process, a lot of friction occurs due to the use of a reformatted dredge. Therefore, a lot of research needs to be conducted in the near future.

• 한국염색가공학회지
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• 제27권4호
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• pp.309-317
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• 2015

This study is the high contraction processing conditions set by the method of the CPB process. And the ultimate goal of this study is the high contraction of the CPB processing test method that can solve the problems of the high-contraction fabric processing method of the current jet dyeing machine. Non-coating process(CPB process) developed by the expression of a soft touch, light weight, functional and to develop excellent breathable nylon fabric. The nylon fabrics established the optimum processing conditions through the high contraction of the various test conditions, the CPB system.(The benzyl alcohol was used as the main constrictor.) At this time, the warp and weft contraction of nylon fabric was about 20%. And it established the constrictor concentration, the treatment temperature, time of a variety of tests. Also non-coating process(CPB process) can develop soft touch, lightweight, excellent air permeability. As a result, we developed a high contraction nylon fabric having a uniform surface. Manufactured fabric is used for Wind-proof and Down-proof.

• 한국분무공학회지
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• 제12권3호
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• pp.160-165
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• 2007

In this study, the breakup characteristics of mono disperse droplets were studied with various fuels, ethanol, diesel fuel, biodiesel fuel extracted from soybean oil, and pure water. In order to investigate the droplet behavior in air cross-flow conditions, the experimental equipment was composed of a droplet generator with an air nozzle, and a high-magnification photo detecting system. Droplets produced by the droplet generator were injected into the air stream flowing normal to a direction of liquid drop jet. Digital images of the droplet behavior in air flow field were recorded by controlling the air flow rate. From the inspections, droplet breakup mechanism is primarily classified into the two kinds of stage, first breakup stage and second breakup stage. At the first breakup stage, droplet deformation rate seems to be affected by the force induced by the surface tension and the viscosity. On the other hand, at the second breakup stage, droplet is broken up mainly induced by the surface tension, so the breakup transition can be divided by the regular Weber number.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.106-109
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• 2007

The spray plume characteristics of liquid water jet injected into subsonic cross-flow at 42 m/s were experimentally investigated. Nozzle has a 1.0 m diameter and L/D=5. Droplet sizes, velocities, volume flux were measured at each downstream area of the injector exit using phase Doppler particle anemometry. Measuring probe position is moved with 3-way transversing machine. Experimental results indicate that SMD is varied from 75 to $120{\mu}m$ distribution and it is uncertain layer structure. SMD peaks at the top of the spray plume. This phenomenon is related to the momentum exchange between column waves and cross-flow stream. Droplet vector velocities were varied from 11.5 to 33 m/s. A higher-velocity region can be identified in down edge region at Z/D : 40, 70 and 100. Lower-velocity region were observed on bottom position of the spray plume. Volume flux is a criterion to the droplet concentration. All volume flux distribution has a same structure that continuously decreases from the center region to the edge of the plume. Z/D : 20 is spatially less concentrated than in Z/D : 100.

• Ocean Systems Engineering
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• 제1권1호
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• pp.31-57
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• 2011

Impact pressure due to sloshing is of great concern for the ship owners, designers and builders of the LNG carriers regarding the safety of LNG containment system and hull structure. Sloshing of LNG in partially filled tank has been an active area of research with numerous experimental and numerical investigations over the past decade. In order to accurately predict the sloshing impact load, a new numerical method was developed for accurate resolution of violent sloshing flow inside a three-dimensional LNG tank including wave breaking, jet formation, gas entrapping and liquid-gas interaction. The sloshing flow inside a membrane-type LNG tank is simulated numerically using the Finite-Analytic Navier-Stokes (FANS) method. The governing equations for two-phase air and water flows are formulated in curvilinear coordinate system and discretized using the finite-analytic method on a non-staggered grid. Simulations were performed for LNG tank in transverse and longitudinal motions including horizontal, vertical, and rotational motions. The predicted impact pressures were compared with the corresponding experimental data. The validation results clearly illustrate the capability of the present two-phase FANS method for accurate prediction of impact pressure in sloshing LNG tank including violent free surface motion, three-dimensional instability and air trapping effects.

• Corrosion Science and Technology
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• 제7권5호
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• pp.274-282
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• 2008

Ships' hull is typically protected by a combination of protective coating system and electrical cathodic protection system, which has been an economical and effective measure for ship's hull to date. However, ships' rudder and adjacent hull areas are known to be subjected to premature corrosion damages, which require more frequent coating repair than other hull areas. Conventional organic coating system for ship's hull has been known only to remain intact just for 2~3 months on the rudder and adjacent area, especially for the fast-going ships such as container carriers or naval vessels. In this study, special organic/inorganic coating materials, which are commercially available, were tested in terms of cavitation resistance as an alternative to existing rudder & hull protection system. Both standard ultrasonic tester and in-house developed ultra water jet test method were employed as a means to evaluate their performance against cavitation induced damages. Additionally, the overall cost evaluation and workability at actual shipyard were discussed.