• Journal of Energy Engineering
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• v.17 no.1
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• pp.8-14
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• 2008

The effects of calcium type catalysts addition on the thermal decomposition of low density polyethylene (LDPE) and ethylene vinyl acetate (EVA) resin have been studied in a thermal analyze. (TGA, DSC) and a small batch reactor. The calcium type catalysts tested were calcinated dolomite, lime, and calcinated oyster shell. As the results of TGA experiments, pyrolysis starting temperature for LDPE varied in the range of $330{\sim}360^{\circ}C$ according to heating rate, but EVA resin had the 1st pyrolysis temperature range of $300{\sim}400^{\circ}C$ and the 2nd pyrolysis temperature range of $425{\sim}525^{\circ}C$. The calcinated dolomite enhanced the pyrolysis rate in LDPE pyrolysis reaction, while the calcium type catalysts reduced the pyrolysis rate in EVA pyrolysis reaction. In the DSC experiments, addition of calcium type catalysts reduced the melting point, but did not affect to the heat of fusin. Calcinated dolomite reduced 20% of the heat of pyrolysis reaction. In the batch system experiments, the mixing of calcinated dolomite and lime enhanced the yield of fuel oil, but did not affect to the distribution of carbon numbers.

• Journal of Life Science
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• v.26 no.5
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• pp.503-508
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• 2016

Biosensors have been used as first-step monitoring tools to detect on-site samples in a simple and cost-effective manner. Numerous recombinant microbial biosensors have been exploited for monitoring on-site toxic chemicals and biological signals. Herein, a recombinant microbial biosensor was constructed for monitoring cadmium. The cadmium responding cadC regulatory gene and it’s promoter from Staphylococcus aureus was amplified through PCR, fused with the lacZ gene, and transformed into Escherichia coli BL21 (DE3) cells. In the presence of cadmium, the biosensor cells express β-galactosidase showing red color development with chlorophenol red β-galactopyranoside (CPRG) as the enzymatic substrate. The biosensor cells showed the best β-galactosidase activity after 3 hr induction with cadmium at pH 5 and a detection range from 0.01 μM to 10 mM cadmium with a linearity from 0.01 to 0.1 μM cadmium (y = 0.98 x + 0.142, R² = 0.98). Among the heavy metals, cadmium and lead showed good responses, tin and cobalt showed medium responses, and mercury and copper showed no responses. The biosensor cells showed good responses to several waste waters similar to buffer solution, all spiked with cadmium. The biosensor described herein could be applied for on-site cadmium monitoring in a simple and cost-effective manner without sample pretreatments.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.4
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• pp.268-273
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• 2014

Experiments on carbonization were conducted using fish offal generated from fish market for the purpose of resource recycling. Elemental composition of fish offal and effect of carbonation temperature on the overall yield were investigated. Carbon and hydrogen contents of fish offal were 51.1% and 7.6%, respectively in view of elemental composition. Particularly, nitrogen and sulfur contents were as high as 9.8% and 1.0%, respectively. These values suggests that odor problem of fish offal can be serious. Comparing elemental composition of fish offal with other waste materials, it is thought that carbon and hydrogen contents are considerably high. These implies that thermal disposal will be the best option for final disposal method of fish offal. As a results of carbonization experiments on Mackerel, Hairtail, Croaker and mixed sample of Mackerel, Hairtail and Croaker, carbonization patterns were quite similar irrespective of fish species. Carbonization yield was varied significantly depending on carbonization temperature at the carbonization time of 5 minutes and 10 minutes. When the carbonization time was maintained longer than 30 minutes, yield variation depending on time variation at each temperature was insignificant. Thus, it can be concluded that effect of carbonization time on overall yield was minor when the carbonization time was maintained longer than 30 minutes. Primary vaporization in carbonization conducted at the temperature of $400^{\circ}C$ was minor. Thus, difference of yield between temperature of $500^{\circ}C$ and $400^{\circ}C$ was appeared greatly. It can be concluded that yield difference depending on carbonization temperature can be neglected if the carbonizing temperature exceed $600^{\circ}C$ and carbonizing time exceed 10 minutes at the same time.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.4
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• pp.86-94
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• 2015

Torrefaction is a thermochemical process proceeded at the temperature around $250^{\circ}C$ in an inert gas condition. By torrefaction, the hemicellulose portions contained in biomass are broken down to change into the volatile gas which is removed from biomass eventually. The main purpose of biomass torrefaction is to improve the energy density of the biomass to minimize the transport energy consumption, though the flammability can be elevated for transportation. In this study two types of solid biomass fuel, waste wood and rice straw, were torrefied at various temperature range from $200^{\circ}C$ to $300^{\circ}C$ to evaluate the torrefied biomass characteristics. In addition torrefied biomass were tested to evaluate the combustion characteristics using TGA (Thermogravimetric Analysis). After the torrefaction of biomass, the C/H (carbon to hydrogen ratio) and C/O (carbon to oxygen ratio) were measured for aquisition of bio-stability as well as combustion pattern. Generally C/H ratio implies the soot formation during combustion, and the C/O ratio for bio-stability. By torrefaction temperature at $300^{\circ}C$, C/H ratio and C/O ratio were increased by two times for C/H and three times for C/O. The torrefied biomass showed similar TGA pattern to coal compared to pure biomass; that is, less mass decrease at lower temperature range for torrefied biomass than the pure biomass.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.42-45
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• 2008

It has been reported that FRP (fiber reinforced plastic) can be recycled by separating into layers instead of crushing into powder. F-fiber obtained from roving layer separated from FRP, has bigger tensile strength than the bundle of glass fibers of which FRP was made (more than 90%). SEM image of F-fiber shows the presence of some resin. Under the proposition of usage of F-fiber in the concrete material, tensile strength is examined after soaking in a basic solution (NaOH+KOH). The reaction mechanism of strength loss may be considered as an attack of hydroxide ion ($OH^-$) on a chemical bond of Si-O-Si of glass fiber. The simulation graph of the strength loss data implies certain reaction mechanism. While in the early stage kinetically controlled reaction results in a fast drop of tensile strength, after 30 days dispersion rate of hydroxide ion plays a major role in strength loss. This result is similar to the one for the AR glass. An extrapolation of the graph would make an assumption about the lift time of F-fiber possible.

• Journal of Korean Medical classics
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• v.13 no.2 s.17
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• pp.21-21
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• 2000

All living things including human being consist of soul(spirit) and body. Soul is the root of a life and body frames it. I wrote this paper to tell how internal injury due to endogenous etiological factors and affection due to exegenous pathogenic factors, affect the internal organs and the external bodily from. This paper begins with description of the patterns of disharmony of the internal organs. General disorders of each Five-Jang(五藏) an be classified into two types of soul and body. The Liver and the Heart which lead changing to Yang(陽) of vital energy, have close relationship with spiritual symptoms because spirit is related to Yang. The Lung, Kidneys, the Spleen which lead changing to m(陰) of vital energy, mainly connected with physical disorders because body is relatively close to m. The Five-Jang are ruled by the Five-Phases(五行) system and cause troubles with Oche(五體) and the nine body orifice. Otherwise the main function of the Six-Bu(六府) is to receive food, absorb the usuable portions, and transmit and excrete waste. Therefore they can cause such problems as abdominal pain, distention, difficulty in urination, and constipation. The spleen is responsible for sending Grain-Ki)穀氣) 내 that is closely connected with the six-Bu. The Gall bladder takes care of control of giving out spirit. That's why it presents many symptoms related to the spirit that is ruled by the Five-Jang. Patterns of disharmony of external bodily form is influenced by the state of Maridians. Bodily forms get divided into many parts by the function of six-meridians(六經) to which they belong. Six-meridians have their own function related to excretion, related to excretion, retention, and balance(開闔樞). If local bodily froms get affected by pernicious influences, the Meridians to which they are attached will lose harmony and connot fulfil their own functions. Because the meridian symtem unifies all parts of the body, the whole body will be under the influence of the affection although local parts of the bodily forms get affected. Therefore the symptoms of disharmony should be considered in a synthetic view. There are however, also cases which should be focused on the very meridian channels affected. Disorder within a Meridian generates derangement in the pathway make it not to benefit the muscles and skin belong to it. Because the meridians connect the interior organs with the exterior bodily form, they are influenced by each other.

• Journal of Korean Medical classics
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• v.13 no.2 s.17
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• pp.22-42
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• 2000

All living things including human being consist of soul(spirit) and body. Soul is the root of a life and body frames it. I wrote this paper to tell how internal injury due to endogenous etiological factors and affection due to exogenous pathogenic factors, affect the internal organs and the external bodily from. This paper begins with description of the patterns of disharmony of the internal organs. General disorders of each Five-Jang(五藏) an be classified into two types of soul and body. The Liver and the Heart which lead changing to Yang(陽) of vital energy, have close relationship with spiritual symptoms because spirit is related to Yang. The Lung, Kidneys, the Spleen which lead changing to m(陰) of vital energy, mainly connected with physical disorders because body is relatively close to m. The Five-Jang are ruled by the Five-Phases(五行) system and cause troubles with Oche(五體) and the nine body orifice. Otherwise the main function of the Six-Bu(六府) is to receive food, absorb the usable portions, and transmit and excrete waste. Therefore they can cause such problems as abdominal pain, distention, difficulty in urination, and constipation. The spleen is responsible for sending Grain-Ki(穀氣) so that is closely connected with the six-Bu. The Gall bladder takes care of control of giving out spirit. That's why it presents many symptoms related to the spirit that is ruled by the Five-Jang. Patterns of disharmony of external bodily form is influenced by the state of Meridians. Bodily forms get divided into many parts by the function of six-meridians(六經) to which they belong. Six-meridians have their own function related to excretion, related to excretion, retention, and balance(開闔樞). If local bodily forms get affected by pernicious influences, the Meridians to which they are attached will lose harmony and cannot fulfil their own functions. Because the meridian system unifies all parts of the body, the whole body will be under the influence of the affection although local parts of the bodily forms get affected. Therefore the symptoms of disharmony should be considered in a synthetic view. There are however, also cases which should be focused on the very meridian channels affected. Disorder within a Meridian generates derangement in the pathway make it not to benefit the muscles and skin belong to it. Because the meridians connect the interior organs with the exterior bodily form, they are influenced by each other.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1359-1367
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• 2008

We analyzed the physical and chemical properties such as proximate analysis, ultimate analysis, heating values, thermogravimetric analysis, and combustion test for the organic sludges generated from paper and beverage manufacturing industries in the industrial complex. The average water and combustible content of the organic sludges from paper and beverage manufacturing industries were 66.07% and 14.67%, 54.98% and 26.77%, respectively. From the ultimate analysis of the organic sludges, C, H, O, N, and S compositions were 21.75%, 3.42%, 32.70%, 0.63%, and 0.30%, respectively. For beverage manufacturing industries, C, H, O, N, and S compositions were 39.88%, 4.28%, 23.20%. 2.65%, and 0.35%, respectively. According to the results of investigating the lower heating values by Dulong's equation, 1 sludge(T company) was on the range of over 2,000 kcal/kg. This sludge could be directly applied to industries which try to use the energy by direct incineration. From the TGA test, the minimum combustion temperature of A company's sludge was about $700^{\circ}C$ for direct use for energy and that of 3 sludges(C, I, and T company) were at least over $800^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.4019-4023
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• 2014

This study examined the effectiveness of ultrasound on enhancing the dewaterability and volume reduction of bio solids from a waste treatment plant. The test specimen was obtained from a storage tank immediately before the dewatering process at a local treatment plant. The test conditions included the energy levels of ultrasonic waves and treatment time. The tests were undertaken using three types of different treatment processors (7 liter, 1 ton, 7 ton container). The capillary suction time (CST) and the viscosity of sludge, which is one of the influencing factors for dewaterbility, were obtained under various test conditions. The results showed that ultrasound increases the CST of the raw specimens, whereas a significant reduction (20 % of the maximum value) of CST occurred in the sample with ultrasound and flocculent. The decrease in viscosity reached 40 % of the maximum value. A centrifugal test was performed to examine the characteristics of the sludge settlement. The settling rate and time required to reach the final values were both enhanced by the ultrasonic energy. An ultrasonic treatment is potentially useful tool for reducing the amount of released sludge. To examine the possible use of field application, the real scale sonic processor was designed and operated. The results were similar (50 % of the maximum value) to those of laboratory experiments.

• The KIPS Transactions:PartC
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• v.18C no.5
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• pp.303-316
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• 2011

Data aggregation is important in wireless sensor networks. However, it also introduces many security problems, one of which is that a compromised node may inject false data or drop a message during data aggregation. Most existing solutions rely on encryption, which however requires high computation and communication cost. But they can only detect the occurrence of an attack without finding the attacking node. This makes sensor nodes waste their energy in sending false data if attacks occur repeatedly. Even an existing work can identify the location of a false data injection attack but it has a limitation that at most 50% of total sensor nodes can participate in data transmission. Therefore, a novel approach is required such that it can identify an attacker and also increase the number of nodes which participate in data transmission. In this paper, we propose a monitoring-based secure data aggregation protocol to prevent against a compromised aggregator which injects false data or drops a message. The proposed protocol consists of aggregation tree construction and secure data aggregation. In secure data aggregation, we use integration of abnormal data detection with monitoring and a minimal cryptographic technique. The simulation results show the proposed protocol increases the number of participating nodes in data transmission to 95% of the total nodes. The proposed protocol also can identify the location of a compromised node which injects false data or drops a message. A communication overhead for tracing back a location of a compromised node is O(n) where n is the total number of nodes and the cost is the same or better than other existing solutions.