• Membrane and Water Treatment
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• v.9 no.6
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• pp.435-445
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• 2018

In this work, desalination experiments were performed on vacuum membrane distillation (VMD). Process parameters such as feed flow rate, vacuum degree on permeate side, feed bulk temperature and feed salt concentration were optimized using sensitivity analysis and Taguchi method. The optimum values of process parameters were found to be 2 lpm of feed flow rate, $60^{\circ}C$ of feed bulk temperature, 5.5 kPa of permeate-side pressure and 5000 ppm of salt concentration. The permeate flux at these conditions was obtained as $26.6kg/m^2{\cdot}hr$. The rejection of salt in permeate was found to be 99.7%. The percent contribution of various process parameters using ANOVA results indicated that the most important parameter is feed bulk temperature with its contribution of 95%. The ANOVA results indicate that the percent contribution of permeate pressure gets increased to 5.384% in the range of 2 to 7 kPa as compared to 0.045% in the range of 5.5 to 7 kPa.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.232-239
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• 2001

The present study is an experimental investigation of nucleate boiling heat transfer mechanism in pool boiling from wire heaters immersed in saturated FC-72 coolant and water. The vapor volume flow rate departing from a wire during nucleate boiling was determined by measuring the volume of bubbles, varying $25{\mu}m,\;75{\mu}m,\;and\;390{\mu}m$, from a wire utilizing the consecutive-photo method. The effects of the wire size on heat transfer mechanism during a nucleate boiling were investigated by measuring vapor volume flow rate and the frequency of bubbles departing from a wire immersed in saturated FC-72. One wire diameter of $390{\mu}m$ was selected and tested in saturated water to investigate the fluid effect on the nucleate boiling heat transfer mechanism. Results of the study showed that an increase in nucleate boiling heat transfer coefficients with reductions in wire diameter was related to the decreased latent heat contribution. The latent heat contribution of boiling heat transfer for the water test was found to be higher than that of FC-72. The frequency of departing bubbles was correlated as a function of bubble diameters.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.59-66
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• 2016

Pollution contribution rate that is effect on water quality from land based load in Masan bay was showed quantifiably for coastal water quality management by using ecological model. It was calculated by difference of water quality concentration at each points t hat is calculated by each scenarios that are presence or absence of each sources (16 points). Results show that, rivers of Northern Masan bay contributed in Masan bay COD is 20 %, T-P is 62 % at northern part and COD is 10 %, T-P is 16 % at middle part. As a result, rivers of Northern Masan bay had effect on water quality of northern Masan bay and middle Masan bay. Also, T-P load affects water quality bigger than COD load, because T-P contribution rate bigger than COD contribution rate of northern rivers. Dukdong WTTP that is land pollution source of southern Masan bay contributed in Masan bay COD is 26 %, T-P is 11% at middle part, COD is 17 %, T-P is 7 % at middle part and COD is 10 %, T-P is 1 % at outer part. It affects water quality bigger at southern and middle of Masan bay than outer bay, because residual flow of bottom flows toward inner of Masan bay nearby Dukdong WTTP.

• Journal of Ocean Engineering and Technology
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• v.1 no.2
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• pp.83-92
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• 1987

Inorder ot estimate the running life of turbine rotors, fatigue crack propagation low, da/dN = C(${\DELTA}K)^m$, proposed by paris et al. has been widely applied. In this study, fatigue crack propagation rates for 16 samples of 1% Cr-Mo-V rotor steel were measured and statistical characteristics of m and C values in above equation were reviewed. The results are summarized as follows. 1. C and m follow a log-normal distribution and normal distribution, respectively. And the relation of C and shows a strong negative correlation. 2. Fatigue crack propagation equation can be expressed as da/dN=$4.11{\times}10^{-4}({\Delta}K/153.8)^m$, introducing the ralationship C=$C_oK_o^{-m}$. In this case, contribution of $C_o$ distribution to the distribution of log C shows very small compared to degrees of contribution by m.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.222-227
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• 2016

In this paper, the optimized design for bow structure was investigated by using EDISON software. Considering the mechanism of the bow, non-linear FEM analysis was essential. The factors of the design are height, width, number of holes and taper value. High performance of the internal energy and lowest mass were main issues. The limit of the von-mises stress was yield strength for the material. Material was chosen by considering typical bow material, Aluminum. Using Taguchi method($L_9$), 9 models were selected and contribution rate was calculated for each factors. Following the contribution rate, 3 factors were fixed and optimized model was predicted. After making optimized model for FEM analysis, the value of internal-energy, mass for FEM model were compared with predicted value, calculated the percentage error and figure out the reliability of Taguchi method.

• Bulletin of the Korean Chemical Society
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• v.12 no.1
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• pp.47-51
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• 1991

Spin-lattice relaxation of methyl protons in 2,6-dichlorotoluene and N-methyl phthalimide, each dissolved in CDCl$_3$, has been studied at 34$^{\circ}$C and the contribution from spin-rotation interaction to the relaxation process has been separated from that due to dipole-dipole interactions among methyl protons. The results show that the spin-rotational contributions to the initial rate of relaxation in 2,6-dichlorotoluene and N-methyl phthalimide amount to 18 and 31%, respectively, of the total relaxation rate at 34$^{\circ}$C. The method of separating the spin-rotational contribution from that of dipolar interactions adopted in this paper is based on the well known fact that in an A$_3$ spin system such as methyl protons in liquid phase dipolar relaxation mechanism gives non-exponential decay of the z-component of total magnetization of protons while the random field fluctuation such as spin-rotational mechanism causes exponential decay.

• Journal of Information Science Theory and Practice
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• v.2 no.1
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• pp.22-34
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• 2014

This paper analyzes India's contribution to world tribology research during the period 2001-2012 based on SCOPUS records. India's global publication share, annual output, and its citation impact of Indian contribution, partner countries, leading contributors, leading institutes, and highly cited papers were analyzed. Additionally, a cloud technique is used to map frequently used single words in titles. It is observed that India ranks in the $7^{th}$ position with a global publication share of 3.83% and an annual average growth rate of 25.58% during the period 2001-2012. The citation impact of India's contribution is 6.05 which decreased from 12.74 during 2001-2006 to 4.62 during 2007-2012. 17.4% of India's total research output was published with international collaboration.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.517-533
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• 2018

We utilize the CAMx (Comprehensive Air Quality Model with eXtensions) system and the PSAT (Particulate Source Apportionment Technology) diagnostic tool to determine the $PM_{2.5}$ concentration and to perform its source apportionment in the southeastern region of South Korea. For a year-long simulation, eight local authorities in the region such as Pohang, Daegu, Gyeongju, Ulsan, Busan-Gimhae, Gosung-Changwon, Hadong, and all remaining areas in Gyeongsangnam-do, are selected as source areas based on the emission rates of $NO_x$, $SO_x$, VOC, and primary PM in CAPSS (Clean Air Policy Support System) 2013 emissions inventory. The CAMx-PSAT simulation shows that Pohang has the highest $PM_{2.5}$ self-contribution rate (25%), followed by Hadong (15%) and Busan-Gimhae (14%). With the exception of Pohang, which has intense fugitive dust emissions, other authorities are strongly affected by emissions from their neighboring areas. This may be measured as much as 1 to 2 times higher than that of the self-contribution rate. Based on these estimations, we conclude that the efficiency of emission reduction measures to mitigate $PM_{2.5}$ concentrations in the southeastern region of South Korea can be maximized when the efforts of local or regional emission controls are combined with those from neighboring regions. A comprehensive control policy planning based on the collaboration between neighboring jurisdictional boundaries is required.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.05a
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• pp.276-277
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• 2004

• The Journal of Asian Finance, Economics and Business
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• v.6 no.2
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• pp.75-82
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• 2019

The paper aims to investigate the impacts of long-term savings motives on fostering household participation and contribution to savings mechanisms in rural Vietnam. The paper is organized in five parts: introduction, data description, methodology, empirical results, and conclusion. The quantitative methodology is employed and three simultaneous estimation methods, including instrumental variable model, two-step model, and Heckman model are used to test these impacts as well as the robustness of results. In each model, the paper examines the impacts of independent factors on both household participation and household contribution to savings mechanisms. Two sets of independent variables: long-term savings motives (profit-making investment, accumulation for big expenditure, providing for old age, and cost of educations) and control variables (dependency rate, number of people in household, and household wealth) are in each model. A set of dataset of 2,314 households for analysis is obtained from household survey in rural Vietnam. Robust statistical findings indicate that profit-making investment emerged to be the strongest motive fostering household participation to savings mechanisms while other long-term savings motives have little or no impact on fostering household participation to savings mechanisms. In addition, education investment encourages household contribution to savings mechanisms in rural Vietnam.