• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.77-84
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• 2021

To control hot spot in a plug flow reactor (PFR) is important for the yield and purity of products and safety. In this paper, coolant temperature is set as a state variable, and radial distributions of heat and mass are considered to model the PFR more realistic than without considering radial distributions. The model consists of three state variables, reactant concentration, reactant temperature, and the coolant temperature. The flow rate of the isothermal coolant is a manipulated variable. This paper shows that the controller considering the radial distributions of heat and mass is more effective than the controller without them. Assuming that u3,0 is 0.7, the suggested control equation was robust when St is bigger than 1.3, and Ac/A is smaller than 2.0. Under this condition, the hot spot temperature changed within the relative error of one percent when the temperature of input altered within the range of five percent.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.9
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• pp.27-34
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• 2018

The purpose of this study is to demonstrate and analyze the function of a Smart Plug before and after it is applied on the electrical appliances by controlling standby power usage. The research measures and analyzes the amount of electrical energy used while activating the Smart Plug with two types of appliances in a university facilities. The smart plugs were applied into a Group 1 appliances (Multi-function device, computer, laptop, Air con) which completely hinder the standby power, and a Group 2 appliances (Refrigerator, cold and hot water dispenser) which does not completely hinder the standby powers due to the characteristics of the function. First, the total standby power saving of all electrical appliances (Group 1 and Group 2) using the Smart plug was measured as 4.59%. Second, the energy saving of the Group 1 products was analyzed as 26.43%. Third, the standby power saving of the air conditioners from mid October to early December was measured as 31.06%, during the seasons when air conditioning was not actively in use. The research indicates that all specified appliances did have better energy efficiency with the Smart plug regardless of the amount of energy usage.

• Korean Journal of Organic Agriculture
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• v.14 no.1
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• pp.85-95
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• 2006

The investigation of the effect of the deep sea water in different concentration (0%, 10%, 20%, 30%, 40%) on the inhibition of growth, fresh weight, dry weight of the tomato, hot pepper, cucumber plug seedlings were conducted. As the concentration of the deep sea water was higher, the greater inhibition was noticed. The height were decreased at the rate of 8%, 25%, 32% in tomato, 9%, 26%, 27% in hot pepper, and 21%, 50%, 58% in cucumber plug seedlings as compare to local check. The fresh weights were decreased highly, as the concentration of the deep sea water increased. Tomato seedlings showed the decrease rate of 12%, 23%, 33% at above the ground part of plants, and 2%, 30%, 52% at under the ground parts. Likewise, Hot pepper seedlings showed the decrease rate of 1.1%, 5.7%, 15.4% at above the ground part of plants, and 22.1%, 25%, 47.1%, respectively at under the ground parts. The fresh weight of cucumber was decreased at the rate of 8.1%, 36%, 51% in the above the ground, and 6.2%, 11%, 65% at the under the ground parts. In tomato, hot pepper, and cucumber seedlings, the dry weight was decreased as the concentration of deep sea water was increased. Thirty percent of deep sea water treatment reduced the dry weight of the seedlings as half of the control seedlings. One of the important factors of the seedling quality is compactness. Compactness was highest at 20% deep sea water in all the three crop seedlings.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.145-148
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• 1999

The ability to rapidly create and deploy new and novel services in response to market demands will be the key factor in determining the success of the future service provider. This goal may be approached from different directions. One of them is an open interface making the functionalities of a network element programmable and usable by outside entities. In this paper, we describe several aspects of this new, hot technical area and introduce related standard activities. In addition, we present a new switching system called MSMP (Multi-Service Multi-Plug-In), which is based on the open programmable interface concept, and describe its architecture and main functionalities of its components.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.11a
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• pp.63-70
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• 2002

The purpose of the present study is to propose a new way of manufacturing curved metal tubes with arbitrary sections and way of eliminating the conventional bending defects such as thinning and thickening, in the wall of tube, distortion of the section, and wrinkling and folding on the surface by the extrusion bending process that can extrude and weld together one or more billets inside dies cavity, and can bend them during extrusion due to the gradient of extrusion velocities controlled by the eccentricity of the cavity sections between the entrance and the exit of the eccentric conical extrusion bending dies and conical plug, or by the relative size of the holes of multi-hole container, or by the relative moving velocity of multi-punches.

• Journal of Mechanical Science and Technology
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• v.14 no.8
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• pp.891-899
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• 2000

The flame speed may be decomposed into the burning speed and the flame transport speed. The flame transport speed is affected considerably by the flow direction, variation rate of flow direction, and flow speed in the combustion chamber. Especially, the flow direction and the variation rate of flow direction at the spark plug location during the ignition period have an important effect on the ignition process and the early flame propagation process. We measured the flow direction component and the variation rate of flow direction with a hot wire probe at the spark plug location. It was shown that the representative flow direction of ignition period is the right-vertical direction of crank shaft and it was used to investigate the variation rate of flow direction.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2423-2430
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• 1994

Several factors of the efficient combustion process are shape of combustion chamber, position of spark plug, turbulence flow and so on. the shape of combustion chamber and position of spark plug are constrained to geometrically, and then it could not make a change the shape easily. But the turlence flow in combustion chamber have a great influence on combustion phenomena, and which is much easier to control relatively. And since characteristics of turbulence flow would be very important to the stability of combustion and performances, This study is also essential to future engine-low emission and lean burn engine. This paper shows that the visualization of the turbulence flow of single cylinder engine by using 2way, $45^{\circ}$ inclined and 2 channel hot wire probe through the park plug hole. We also study the characteristics of turbulence flow by means of ensemble averaged mean velocity, turvulence intensity and integral length scale.

• Journal of Bio-Environment Control
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• v.12 no.4
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• pp.252-258
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• 2003

This experiment was performed to investigate the effect of UV-B (4 kJ${\cdot}m^{-2}{\cdot}d^{-1}$) irradiation and growth inhibitor (50 mg${\cdot}L^{-1}$ diniconazole, 500 mg${\cdot}L^{-1}$) treatment on the overgrowth retardation and the growth and yield afterplanting in plug-grown cucumber, tomato, and hot pepper sedlings. Stem length of UV-B-irradiated and iniconazole-treated seedlings was shortened by 38 and 35%^ in cucumber, 37 and 41% in tomato, and 23 and 23% in hot pepper, respectively, compared with non-treated seedlings. While retarding effect ofhexaconazole waslower that that of UV-B or diniconazle. Leaf area and dry weight alson decreased but ldaf thickness increased in UV-B irradiated or growth-inhibitor-treated seedlings. Even thouth the plant height and leaf area of UV-B-irradiated seedlings ant seedling stage were shorter and smaller that those ofnon-treatedd seedlings, they were recovered to the similar level to the growth of non-treated seedlings 20to 30days after trasplantin. The diconazole-and hexaconazole-treated seedlings were delayed recovery to their normal growth, Fruit yiedl of UV-V-irradiated hot pepper and tomato slightly increased but UV-B irradiated cucumer had similar yield to growth-inhibitor-treated one. It suggested that the use of UV-B irradiation could become a reliable tool of overgrowth retardation of plug-grown vegetable seedlings in greenhouse.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.369-376
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• 2006

This research was conducted to evaluate the effect of root medium formulations on growth and nutrient uptake of hot pepper 'Knockgwang' in 72-cell plug trays. To achieve this, the nine root media were formulated by adjusting blending rate of perlite (PL) to coir (CO), peatmoss (PM) or coir+peatmoss (5:5, v/v, COPM). Then, the growth characteristics and tissue nutrient contents were determined at 35 and 70 days after sowing. The elevated blending rate of PL to CO increased fresh and dry weight of hot pepper at 35 days after sowing. The treatments of 20% in blending rate of PL to PM or that of 0% to COPM produced the highest fresh and dry weight among perlite treatments of PM or COPM. The results of crop growth at 70 days after sowing also showed similar trends to those of 35 days after sowing. The elevated blending rate of PL to CO or PM decreased tissue $P_2O_5$ and K contents and increased Ca and Mg contents at 35 days after sowing, With the equal blending rate of perlite, the plant tissue grown in CO had higher K contents and lower N, Ca and Mg contents than those in PM and COPM. The elevated blending rate of perlite in three organic matter also decreased tissue $P_2O_5$ and K contents at 70 days after sowing, but Ca and Mg contents were the highest in the treatment of 20% PL in CO, 40% PL in PM and 40% PL in COPM among perlite treatments in each organic matter.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.4
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• pp.127-131
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• 2010

Stainless steel sheets are widely used as the structural material for the railroad cars and the commercial vehicles. These kinds of structures used stainless steel sheets are commonly fabricated by using the gas welding. For fatigue design of gas welded joints such as fillet and plug type joint, it is necessary to obtain design information on stress distribution at the weldment as well as fatigue strength of gas welded joints. And also, the influence of the geometrical parameters of gas welded joints on stress distribution and fatigue strength must be evaluated. Thus, in this paper, ${\Delta}P-N_f$ curves were obtained by fatigue tests. Using these results, ${\Delta}P-N_f$ curves were rearranged in the. ${\Delta}{\sigma}-N_f$ relation with the hot spot stresses at the gas welded joints.