• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.5
• /
• pp.709-716
• /
• 2016

Recently, the operating conditions of the various mechanical structures have become more severe and the running time has become longer as the development of plant equipment increases with the introduction of high technology. Thus, the reliability of the system and its accessories is becoming a problem. Normally, synthetic natural gas (SNG) plants use 1.25Cr-0.5Mo or 2.25Cr-1Mo heat resistant steel according to the operating conditions. In this study, a lab-scale reactor was set up using 1.25Cr-0.5Mo steel, in order to carry out corrosion tests for producing synthetic natural gas. The corrosive characteristics were investigated under 1st-methanator operating conditions and fundamental data about the durability and reliability were obtained by using the experimental test. The analysis of results obtained on the durability of the reactor under emission and injection compositions showed that the hydrogen embrittlement caused by hydrogen and the oxidation corrosion caused by H2O had the most effect on the durability of 1.25Cr-0.5Mo steel in the SNG reactor. However, the hydrogen embrittlement and oxidation corrosion occurred simultaneously under emission conditions, so that the corrosion of the material increased suddenly after a long operating time. Besides, the corrosion of the 1.25Cr-0.5Mo steel under the injection composition was faster than that under the emission composition.

• Journal of Biosystems Engineering
• /
• v.37 no.4
• /
• pp.233-244
• /
• 2012

Purpose: The kinetic evaluation was performed for swine manure (SM) degradation and biogas generation. Methods: The SM was anaerobically digested using batch digesters at feed to inoculum ratio (F/I) of 1.0 under mesophilic conditions ($36.5^{\circ}C$). The specific gas yield was expressed in terms of gram total chemical oxygen demand (mL/g TCOD added) and gram volatile solids added (mL/g VS added) and their effectiveness was discussed. The biogas and methane production were predicted using first order kinetic model and the modified Gompertz model. The critical hydraulic retention time for biomass washout was determined using Chen and Hashimoto model. Results: The biogas and methane yield from SM was 346 and 274 mL/ TCOD added, respectively after 100 days of digestion. The average methane content in the biogas produced from SM was 79% and $H_2S$ concentration was in the range of 3000-4108 ppm. It took around 32-47 days for 80-90% of biogas recovery and the TCOD removal from SM was calculated to be 85%. When the specific biogas and methane yield from SM (with very high TVFA concentration) was expressed in terms of oven dried volatile solids (VS) basis, the gas yield was found to be over estimated. The difference in the measured and predicted gas yield was in the range of 1.2-1.5% when using first order kinetic model and 0.1% when using modified Gompertz model. The effective time for biogas production ($T_{Ef}$) from SM was calculated to be in the range of 30-45 days and the critical hydraulic retention time ($HRT_{Critical}$) for biomass wash out was found to be 9.5 days. Conclusions: The modified Gompertz model could be better in predicting biogas and methane production from SM. The HRT greater than 10 days is recommended for continuous digesters using SM as feedstock.

• Journal of Korean Society on Water Environment
• /
• v.26 no.2
• /
• pp.289-296
• /
• 2010

The purpose of this study is to evaluate various pre-treatment methods and proprieties of water quality for wastewater reuse using reverse osmosis (RO) processes. Secondary effluents were sampled from wastewater treatment plants and lab scale pre-treatments and RO filtration test were conducted systematically. Specifically, different types of pre-treatments, such as coagulation, microfiltration and ultrafiltration, were employed to evaluate the removal efficiency of particle and organic matters which may affect the membrane fouling rate. RO process was later added to eliminate trace amounts of remaining organic matters and salt from the raw water for wastewater reclamation. The permeate through the RO process satisfied water quality regulations for industrial water uses. The experimental results showed that the initial fouling tendency differed not only by the feed water properties but also by the membrane characteristics. Membrane fouling was greater for the membranes with large surface roughness, regardless of the hydrophobicity and zeta potentials. Thus both careful consideration of pre-treatment options and proper selection of RO membrane are of paramount importance for an efficient operation of wastewater treatment.

• Korean Journal of Acupuncture
• /
• v.29 no.4
• /
• pp.623-633
• /
• 2012

Objectives : Fatigue is a common and distressing symptom that is a concern for cancer patients. It has a decisive effect on quality of life. The purpose of this study was to examine the feasibility of clinical trial to evaluate of efficacy and safety of acupuncture on cancer related fatigue of lung cancer patients. Methods : Total lung cancer 9 patients complained of fatigue were treated by acupuncture twice a week for four weeks(8 times in total). Evaluation of the severity of fatigue was measured by FSS(Fatigue Severity Score). In visit 1, 10, we checked FSS. For check safety of acupuncture treatment, we did blood test. Results : After 4 weeks of acupuncture treatment, the FSS was significantly decreased from $4.92{\pm}1.06$ to $3.74{\pm}1.37$(p=0.008). And the level of hemoglobin was significantly increased from 10.87 g/dl to 12.01 g/dl(p=0.014). No other lab measures indicated any significant differences between before and after acupuncture treatment. Conclusions : This study suggests that acupuncture treatment will be beneficial for lung cancer patients to improve the fatigue severity. And acupuncture treatment is safe method for lung cancer patients. A large-scale study to confirm efficacy and safety of acupuncture is needed.

• Journal of Soil and Groundwater Environment
• /
• v.17 no.6
• /
• pp.102-111
• /
• 2012

Fine suspended solids generated effluence from treatment process of mine drainage could destroy environment as the aesthetic landscapes, and depreciate water quality. Therefore, the purpose of this research is focused on process development applied the actual field for controlling fine suspended solids and heavy metals, and so lab-scale test was performed for inducement of basic data. The mine drainage used in this research was sampled in H mine located Jeongseon-gun, Gangwon-do. Concentration of suspended solid, arsenic, iron and manganese was exceeded the standard of contaminant limitation for the clean water, and particle size of suspended solid was less than 10 m as fine particle. Although hydraulic retention time of mine drainage for effective settling was required more than 6 hours, hydraulic retention time would be increased in winter season when the settling efficiency could be reduced because of viscosity decreasing. Moreover, installed inclination plate helped to increase settling efficiency of suspended solid about 48 %. Filtering media that was the most effective removal of suspended solids and heavy metal was decided granular activated carbon of 1~2 mm was the optimal size.

• Environmental Engineering Research
• /
• v.15 no.3
• /
• pp.141-147
• /
• 2010

The objective of this study was to assess the biofouling characteristics of the Bacillus biofilm formed on reverse osmosis (RO) membranes. For the study, a sporogenic Bacillus sp. was isolated from the seawater intake to a RO process, with two distinct sets of experiments performed to grow the Bacillus biofilm on the RO membrane using a lab-scale crossflow membrane test unit. Two operational feds were used, 9 L sterile-filtered seawater and 109 Bacillus cells, with flow rates of 1 L/min, and a constant 800 psi-pressure and pH 7.6. From the results, the membrane with more fouling, in which the observed permeate flux decreased to 33% of its initial value, showed about 10 and 100 times greater extracellular polymeric substances and spoOA genes expressions, respectively, than the those of the less fouled membrane (flux declined to 20% of its initial value). Interestingly; however, the number of culturable Bacillus sp. in the more fouled membrane was about 10 times less than that of the less fouled membrane. This indicated that while the number of Bacillus had less relevance with respect to the extent of biofouling, the activation of the genes of interest, which is initiative of biofilm development, had a more positive effect on biofouling than the mass of an individual Bacillus bacterium.

• Smart Structures and Systems
• /
• v.20 no.3
• /
• pp.385-396
• /
• 2017

The recent advancements in sensing technologies allow us to record measurements from target structures at multiple locations and with relatively high spatial resolution. Such measurements can be used to develop data-driven methodologies for condition assessment, control, and health monitoring of target structures. One of the state-of-the-art technologies, Fiber Optic Strain Sensors (FOSS), is developed at NASA Armstrong Flight Research Center, and is based on Fiber Bragg Grating (FBG) sensors. These strain sensors are accurate, lightweight, and can provide almost continuous strain-field measurements along the length of the fiber. The strain measurements can then be used for real-time shape-sensing and operational load-estimation of complex structural systems. While several works have demonstrated the successful implementation of FOSS on large-scale real-life aerospace structures (i.e., airplane wings), there is paucity of studies in the literature that have investigated the potential of extending the application of FOSS into civil structures (e.g., tall buildings, bridges, etc.). This work assesses the feasibility of using FOSS to predict operational loads (e.g., wind loads) on chain-like structures. A thorough investigation is performed using analytical, computational, and experimental models of a 4-story steel building test specimen, developed at the University of Southern California. This study provides guidelines on the implementation of the FOSS technology on building-like structures, addresses the associated technical challenges, and suggests potential modifications to a load-estimation algorithm, to achieve a robust methodology for predicting operational loads using strain-field measurements.

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.5
• /
• pp.526-535
• /
• 2016

Recently, fine dust in atmosphere have been considerably issued as a harmful element for human. Nitrogen oxide ($NO_x$) exhausted from diesel engines and power plants has been disclosed as a main source of secondary production of fine dust. In order to prevent exhausting these nitrogenous compounds into atmosphere, a treatment system with selective catalytic reduction (SCR) catalyst with ammonia as a reductant has been used in various industries. Urea solution has been widely studied to supply ammonia into a SCR catalytic reactor, safely. However, the conversion of urea solution to ammonia has several challenges, especially on a slow conversion velocity. In the present study, a fast urea conversion system including a plasma burner was suggested and designed to evaluate the performances of urea conversion and initial operation time. A designed lab-scale facility has a plasma burner, urea nozzle, mixer, and SCR catalyst which is for hydrolysis of isocyane. Flow rate of methane that is a fuel of the plasma burner was varied to control temperatures in the urea conversion facility. From experimental results, it is found that urea can be converted into ammonia using high temperature condition of above $400^{\circ}C$. In the designed test facility, it is found that ammonia can be produced within 1 min from urea injection and the result shows prospect commercialization of proposed technology in the SCR facilities.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.3
• /
• pp.249-254
• /
• 2017

The paper presents a new short-term dynamic displacement estimation method based on an acceleration and a geophone sensor. The proposed method combines acceleration and velocity measurements through a real time data fusion algorithm based on Kalman filter. The proposed method can estimate the displacement of a structure without displacement sensors, which is typically difficult to be applied to earthquake or fire sites due to their requirement of a fixed rigid support. The proposed method double-integrates the acceleration measurement recursively, and corrects an accumulated integration error based on the velocity measurement, The performance of the proposed method was verified by a lab-scale test, in which displacement estimated by the proposed method are compared to a reference displacement measured by laser doppler vibrometer (LDV).

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.3
• /
• pp.199-204
• /
• 2006

The purpose of this work was to evaluate the development of the anammox process by the use of granular sludge selected from a digestion reactor as a potential seed source in a lab-scale UASB (upflow anaerobic sludge blanket) reactor system. The reactor was operated for approximately 11 months and was fed by synthetic wastewater. After 200 days of feeding with $NH_4^+\;and\;NO_2^-$ as the main substrates, the biomass showed steady signs of ammonium consumption, resulting in over 60% of ammonium nitrogen removal. This report aims to present the results and to more closely examine what occurs after the onset of anammox activity, while the previous work described the start-up experiment and the presence of anammox bacteria in the enriched community using the fluorescence in situ hybridization (FISH) technique. By the last month of operation, the consumed $NO_2^--N/NH_4^+-N$ ratio in the UASB reactor was close to 1.32, the stoichiometric ratio of the anammox reaction. The obtained results from the influent-shutdown test suggested that nitrite concentration would be one key parameter that promotes the anammox reaction during the start-up enrichment of anammox bacteria from granular sludge. During the study period, the sludge color gradually changed from black to red-brownish.