• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.609-616
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• 2011

In the study, we analyzed the collision characteristics of a so-called arch-type submarine cable protector by considering the changes in drop heights of a stock anchor and material models for concrete and steel reinforcing bars. We considered plastic kinematics model and Johnson-Holmquist Concrete model for the concrete and linear elastic model and plastic kinematics model for the reinforcing bars. The drop heights of 2-ton stock anchor were selected as 3, 5, and 8.83m, respectively. ANSYS, a finite element analysis program, was used for the collision analysis. To save computational time, we converted those drop heights into initial velocities by the principle of energy conservation. From the sensitivity of the material models on the drop height changes, it is shown that the collision response of the reinforcing bars is sensitive firstly on the steel models and secondly on the concrete models, while the collision response of the concrete is sensitive only on the concrete models.

• Food Science of Animal Resources
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• v.38 no.4
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• pp.749-758
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• 2018

The objective of this study was to provide preliminary data for food industry by investigating the distribution of microorganisms in raw materials and sausage examining the effect of heating temperature on sausage quality. Total microbes in sausage ranged 2.21-3.11 Log CFU/g. Bacillus pumilus, B. licheniformis, Staphylococcus saprophyticus, and Enterococcus faecalis were detected on sausage. Total microbes in raw materials was 1.59-7.16 Log CFU/g. Different types of microorganisms were found depending on raw materials, with B. pumilus and B. subtilis were being detected in both raw materials and sausage. Total microbes in sausage after heating was in the range of 1.10-2.22 Log CFU/g, showing the trend of decrease in total microbe with increasing heating temperature, although the decrease was not significant. With increasing heating temperature, pH and hardness were also increased. The yield of sausage manufactured at $85^{\circ}C$ was 95.42% while that manufactured at $65^{\circ}C$ was 96.67%. Therefore, decreasing heating temperature during sausage production might increase yield and save energy without microbiological effect.

• KSBB Journal
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• v.16 no.5
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• pp.523-525
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• 2001

Curdlan is one biopolymer composed of ${\beta}$1,3-glucan and dissolved in a alkali solution but formed salt under neutral or acid condition. It was produced by Agrobactrium species and the separation process is necessary to make pure curdlan from the culture broth. The pH swing separation method was as feasible separation process using solubility changes with the pH difference. however, this method requires a lot of acid and alkali solution also produces a lot of waste. Therefore, an efficient process which could save energy and minimize toxic waste was developed. A density gradient separation process was developed in this research. High density sucrose solution was used as a separation agent. Curdlan was separated from the culture broth when the density of the sucrose solution was 1.15 g/L. Since the curdlan was produced on the surface of cell wall. the pre-treatment of culture broth was necessary. Curdlan recovery yield was increased up to 83% with the homogenization of the culture broth and further increased up to 87% with the treatment of alkai-acid solution.

• Journal of Korean Society on Water Environment
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• v.28 no.1
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• pp.129-136
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• 2012

In this century, scientists realized that carbon dioxide gas in the atmosphere cause a greenhouse effect which affects the planet's temperature. Therefore lots of attempts have carried out to decrease the discharge of carbon dioxide gas in the field. The dissolved carbon dioxide flotation (DCF) process was developed as an alternative of DAF process to decrease the discharge and reuse of carbon dioxide as well as to save energy consumption. To investigate the particle separation characteristics and the flotation efficiency of carbon dioxide, SCC model was employed in the DCF process which has been applied extensively for the evaluation and simulation in the DAF process. The simulation results by the SCC model revealed the predicted curve of flotation efficiency became decreased gradually over the optimal pressure range of saturator about 1.6 atm in accordance with the experiment results of the DCF pilot plant and the size distribution and the bubble volume concentration of $CO_{2}$ bubbles depending on the operation pressure of saturator. The findings through the simulation results led to the conclusion that there was no significant difference between $CO_{2}$ bubbles and air bubbles, affecting on the practical flotation efficiency, in terms of the initial collision and attachment efficiency.

• Korean Journal of Poultry Science
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• v.16 no.4
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• pp.233-238
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• 1989

This experiment was carried out to establish effective egg storage technology by studying the physico-chemical properties of albumen and yolk during the cold storage. The results obtained were summarized as follows：1. Egg Yolk was gelated and whipping quality and whipping stability of albumen was decreased by the freezing storage. 2. NaCl was the best anti-freezer to prevent the gelation of egg yolk among various anti-freezer (NaCl, glucose, sucrose, amides). 3. Viscosity of egg yolk and albumen was increased and color was changed but changes of colorin albumen was slight during the storage at $-5^{\circ}C$ and $-20^{\circ}C$. 4. To store the 5% NaC1 added egg yolk -at $-5^{\circ}C$ was the best way to prevent the gelation of egg yolk and save the energy. 5. Emulsion capacity of egg yolk was decreased by the cold storage with the addition of NaCl.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1455-1463
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• 2017

Global economy has recorded low growth, low consumption, high unemployment rate, high risk, short boom and long recession. As a result, maritime economy declines and the reduction of maintenance costs is inevitable. Thus, Studies such as green ship, eco ship, and smart ship are being actively conducted to save energy of ship. Power management system that use batteries in green ship is an important research area. In this paper, we analyze the heavy load control of a power management system of a general ship using only a generator, and study a heavy load control algorithm for a battery connected power management system. To study this, a structure of battery connected power management system is proposed and a battery connected power simulator was constructed based on the proposed system. Through the simulator, the operation of the battery according to the heavy load control is defined and confirmed in the battery connected power management system.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.4
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• pp.82-91
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• 1997

In this paper, a design method of the boiler-turbine control system in the coal fired power plant is proposed. We need to control electric output and drum pressure and water level in drum to guarantee stable operation and save energy for generating electricity and decrease air pollution in the boiler-turbine system. This boiler-turbine control system is composed of reference model part and model following part. The multivariable boiler-turbine system is separated into 3 SISO(Single Input Single Output) systems applying the concept of relative gain matrix. Each 3 reference models for separated boiler-turbine system are composed of 1st order nominal plant and hysteresis integral control system and they make good dy¬namic response with no overshoot and fast rising time. Each fuzzy controller to follow as close as possible to the response of each reference model is designed. The robustness and the good tracking property can be achieved using 5150 fuzzy controllers when there are modeling errors, disturbances and parameter pertur¬bations. The effectiveness of the proposed design method is verified through simulations.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.1 no.2
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• pp.49-56
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• 1987

To save energy consumption, it is proposed to operate a discharge lamp with high frequency power. When designing a high frequency operating circuit containing a discharge lamp, the character of a lamp may be needed. And there are various methods to get and models for this. In this study, to present the volt-ampere character of a fluorescent lamp which gives a good saving effect, the nonlinear resistance model is suggested. And the validity of the model is verified by applying the model for the circuits with inductor ballast and capacifor ballast. This model, in contrast with the others, can be easily obtainable. And for comparison, the model using a modified Francis equation is examined. The method used in this study can be basically applied to the other discharge lamps. As a result, 1) Approximated 3rd order polynomial of nonlinear resistance model gives a good simulation result. 2) When operating in high frequency, the model using a modified Francis equation with constant coefficients can't be applied.

• Resources Recycling
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• v.17 no.2
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• pp.16-29
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• 2008

According to the statistical data of the Ministry of Environment, 47million tons of construction waste were generated, and 96.7% of them was recycled in 2005. However, the recycled products seem to be remained under low quality. Because mixed demolition and construction waste, so called DC Waste, including concrete, brick, plaster, lumber, plastics building materials, paper and some dirt and stone, is very variable and difficult to estimate its exact composition, it is regarded as having little or no value to the construction industry. 'The Research group on recycling of construction waste' was started by the Housing & Urban Research Institute(KNHC), which is sponsored as a large scale national project by the Ministry of Construction and Transportation. This research group intends to establish recycling system through planing, processing, developing practical technology, and eventually contribute to save natural resource and to vitalize the industry. In this paper an overview of DC waste management and recycling technology is given in some detail. Particularly, "recycling law of construction waste" and recent research trends on recycling of construction waste are discussed.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.25-36
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• 2018

Drip irrigation system is a low energy cost method which can efficiently save and supply water by dropping water slowly on the crop's root zone during crop growth. In the drip irrigation system, disk filters take an important role to physically remove impurity (inorganic and suspended organic) particles present in agricultural water which can cause emitter clogging. For the purpose, both top-and-bottom surfaces of the disk are grooved in micron size flowing from outside to inside. However, many congested flow paths in disk filter media incur higher head loss of inflow water resulting in relatively decreasing velocities depending on operation time than sand and mesh filters. Therefore, it is important to optimize the structure of disk filter in micro irrigation system. The head loss of disk filter media takes also charge of more than 60 % of total head loss in whole disk filter. This study is to find the appropriate cross-sectional shape of the disk groove to minimize the head loss by executing the experiment. The experiment used three disk filters that have similar filter body but have a half-elliptic and two kinds of triangular cross sections. The experimental results showed that the disk filter with half-elliptic cross sections of disk grooves have less head loss than the disk filter with regular triangular one.