• Steel and Composite Structures
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• v.34 no.5
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• pp.681-698
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• 2020

The paper addresses contribution to the modeling and optimization of major machinability parameters (cutting force, surface roughness, and tool wear) in finish dry hard turning (FDHT) for machinability evaluation of hardened AISI grade die steel D₃ with PVD-TiN coated (Al₂O₃-TiCN) mixed ceramic tool insert. The turning trials are performed based on Taguchi's L₁₈ orthogonal array design of experiments for the development of regression model as well as adequate model prediction by considering tool approach angle, nose radius, cutting speed, feed rate, and depth of cut as major machining parameters. The models or correlations are developed by employing multiple regression analysis (MRA). In addition, statistical technique (response surface methodology) followed by computational approaches (genetic algorithm and particle swarm optimization) have been employed for multiple response optimization. Thereafter, the effectiveness of proposed three (RSM, GA, PSO) optimization techniques are evaluated by confirmation test and subsequently the best optimization results have been used for estimation of energy consumption which includes savings of carbon footprint towards green machining and for tool life estimation followed by cost analysis to justify the economic feasibility of PVD-TiN coated Al₂O₃+TiCN mixed ceramic tool in FDHT operation. Finally, estimation of energy savings, economic analysis, and sustainability assessment are performed by employing carbon footprint analysis, Gilbert approach, and Pugh matrix, respectively. Novelty aspects, the present work: (i) contributes to practical industrial application of finish hard turning for the shaft and die makers to select the optimum cutting conditions in a range of hardness of 45-60 HRC, (ii) demonstrates the replacement of expensive, time-consuming conventional cylindrical grinding process and proposes the alternative of costlier CBN tool by utilizing ceramic tool in hard turning processes considering technological, economical and ecological aspects, which are helpful and efficient from industrial point of view, (iii) provides environment friendliness, cleaner production for machining of hardened steels, (iv) helps to improve the desirable machinability characteristics, and (v) serves as a knowledge for the development of a common language for sustainable manufacturing in both research field and industrial practice.

• Journal of the Korean Applied Science and Technology
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• v.2 no.1
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• pp.45-55
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• 1985

The present study was designed to investigate the effects of dietary fiber sources and levels on serum lipids in rats fed a hypercholesterol diet containing 0.5% cholesterol. Male Sprague-Dawley rats weighing 52.7 ${\pm}$ 7.27g were devided into sevel groups by completely randomized block design and fed various dietary fibers which were prepared from Rice bran, Siraegi (The dried green parts of a radish) and Bracken Fern at a level of 5% and 10% respectively. The results obtained in this study are summarized as follows: 1. Body weight gains were not significantly different among the groups and food intake was significantly higher in rats fed a diet of Siraegi 10% than those fed the control diet. 2. Fecal wet weights were significantly increased in all experimental groups. 3. Levels of serum total cholesterol in all experimental groups were significantly lower than that of the control group except the level in the R 10(Rice bran 10%) group. 4. Free Cholesterol levels in the serum were increased in all experimental groups, especially the levels in the R 10 (Rice bran 10%) and S 10 (Siraegi 10%) groups were significantly higher than that of the control group. 5. Ester Cholesterol levels in the serum were significantly lower in rats fed the experimental diets than those fed the control diet. 6. There was a tendency of higher serum HDL-Cholesterol levels in R5 (Rice bran 5%), R10 (Rice bran 10%) and B5(Bracken 5%) groups compared to the control group however no significant differences were found between the control group and all the experimental groups except in the case of the S5 (Siraegi 5%) group. 7. LDL, VLDL-Cholesterol levels in the serum sere significantly reduced in the S5 (Siraegi 5%), B5 (Bracken 5%) and B10 (Bracken 10%) groups. 8. The HDL-C./Total-C. Ratio was increased in all experimental group especially the Ratios in the S5 and B5 groups were significantly higher than that of the control group.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.5
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• pp.68-77
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• 2013

Change in the Global Climate causes flood, drought, heavy snow, and rainfall patterns in the Korean Peninsula. A variety of alternatives related to climate change are considered. The foreign researchers are interested in Low Impact Development(LID); the utilization of water resources and eco friendly development, over 10 years ago. The research and development of related technology has been advanced to apply LID techniques in order to develop several projects in the country. However, sharing of technology or system that can be used easily in the private sector is insufficient. The performance of the elements of LID Technology has not been fully agreed. LID elements of this technology are easy to apply to Apartment complex. The elements are classified technology. The infiltration of elements performs the functions of apartment complex landscaping space technology applied to the target. The water cycle simulation(SWMM 5.0) and technology the implementation of the effectiveness is also verified. For this purpose, three different places in apartment complex to target by SWMM5.0 U.S. EPA conducted utilizing simulated rainfall and applying LID techniques before and after the simulated water cycle (infiltration, surface evaporation, and surface runoff) were conducted. The importance of green space in the LID techniques of quantitative and qualitative storm water control as well as the role of Apartment Housing is to promote Amenity. Remember that the physical limitations of apartment complex and smooth water circulation system for the application of LID integrated management techniques should be applied. To this end, landscapes, architecture, civil engineering, environmental experts for technical consilience between the Low Impact Development efforts are required.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.795-806
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• 2016

This study was conducted to improve the continuous techniques for international competitiveness of ginseng industry to Korea-China FTA negotiation and conclusion, and provide the basic information for ginseng industry development of Korea. It was carried out the visiting of the northeastern three provinces (Jilin, Liaoling and Heilongjang) in China for 3-year from 2014 to 2016 and observed the farmers' fields of ginseng cultivation with soil environmental status. The types of ginseng cultivation could be observed in small scales of 0.5~3.0 ha, in middle scales of 4.0~10.0 ha and in large scales of 30~700 ha with the kinds of imhasam, Chinese ginseng, Korean ginseng and western ginseng. Also ginseng was cultivated in newly reclaimed land of forest in two types of direct seeding and transplanting of ginseng seedlings. The field beds of ginseng growing were covered with vinyl films in arch design of 100~130 cm height and vinyl was painted in spraying with blue, green and yellow colours for shading. It was investigated in status of the physico-chemical properties of soils. The physical information on the field soils were silt loam, loam and sandy loam in soil textures, and some plain in low slope, some alluvial fan or local valley in forest of land topography. Soil pH ranged within 5.0~5.2, soil EC was $0.93{\sim}3.78dS\;m^{-1}$, organic matter was $37{\sim}35g\;kg^{-1}$, nitrate nitrogen $63{\sim}490mg\;kg^{-1}$, available $P_2O_5$ $55{\sim}163mg\;kg^{-1}$, and in exchangeable cations, K was 0.30~0.98, Ca was 6.5~14.0, Mg was $1.1{\sim}5.3cmol_c\;kg^{-1}$ in ranges. Farmers used the fertilizer for ginseng cultivation in 10~11 t of compost, $200{\sim}400kg\;ha^{-1}$ of complex fertilizer and $750kg\;ha^{-1}$ of oil cakes. The northeastern three provinces of China can use the newly lands with large areas of ginseng cultivation in soil sickness by continuous cropping. and the soil basic fertility is batter than that of Korean in standard guide of ginseng cultivation soil.

• Food Science and Preservation
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• v.18 no.2
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• pp.178-183
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• 2011

The consumer awareness concerning coffee beverages has increased in Korea. The objective of this study was to optimize the roasting conditions of coffee bean for consumer's attribute. The optimal roasting conditions for Colombian coffee beans were analyzed by using a central composite design with a quadratic polynomial model by response surface methodology (RSM). The experimental conditions for coffee bean roasting were $194.82^{\circ}C{\sim}250.00^{\circ}C$ and 7.93~22.07 minutes. The responses of sensory attributes. physicochemical and physical properties were analyzed with RSM. The width. length and height of green beans increased when the beans were roasted. The higher degree of roasting gave the higher pH and solid contents but the lower total acidity and total phenolic compounds. In sensory tests, the roasting temperature and time had a significant effect on the flavor score. The optimum roasting condition of Colombian coffee bean predicted for maximizing the length, width, solid contents, total phenolic compounds and flavor score were 20 minutes at $225^{\circ}C$ by RSM.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.780-787
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• 2019

As a carbon-free, green growth alternative, internal and external interest in hydrogen energy and technology is growing. Hydrogen was added to co-axial methane, methane-propane, and methane-propane-ethane diffusion flames, which are the main ingredients of LNG, to evaluate its effect on flame formation and combustion products. The variation in combustion products produced by adding hydrogen gradually to diffusion pyrolysis at room temperature and normal pressure conditions was observed experimentally by using a gas analyzer, and the shape of diffusion pyrolysis was observed step by step using a digital camera. The experimental results showed that the production volume of nitrogen oxides tended to increase and became close to linear as hydrogen was added to the diffusion pyrotechnic. This is because the relatively high temperature of heat insulation and fast combustion speed of hydrogen facilitated the production of thermal NOx. On the other hand, CO2 production tended to decrease as hydrogen was added to reduce the overall carbon ratio contained in the mixed diffusion flame of methane, methane-propane, and methane-ethane-propane. This means that the mixed fuel use of LNG-hydrogen in ships may potentially reduce emissions of CO2, a greenhouse gas.

• Journal of Forest and Environmental Science
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• v.23 no.1
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• pp.21-28
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• 2007

In my study, I analysed and criticised the change of applied works based on a design drawing of a private forest road in Chungchengnam province from 1990 to 2003. The aim of this study is to obtain the fundamental resources for establishment the green forest road which is environment friendly. Working expenses of forest road was gradually increased by a business year. In particular, the working expenses dramatically increased in 1999-2000. In change rate of cost of construction by works, earth work rate of the cost of constructions was declined: from 25.4% in 1990-1999, to 18.5% in 2000-2003. However, the total cost of the construction of slope protection work and structural work increased. Nevertheless the rate of the cost of constructions are not increased where as the earth work rate of the cost of constructions were reduced. The rate of the price construction materials and the cost of construction was the main causes which was led by the extension of the standard requirement of applied work and the increase of the materials of applied work. In other word, materials of structural work and slope protection work increased. If the increase of the cost of construction has seem through the increase of contractual materials and extension of the standard requirement would led to weak competitiveness of forest road. Therefore, diverse method of constructions need to apply and a new method should be developed.

• Korean Journal of Construction Engineering and Management
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• v.10 no.1
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• pp.156-166
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• 2009

Residential land development projects are tending upwards recently. However, an indiscreet residential land development has tended to damage environment by destroying existing green lands and trees of target lands and generating many cut slopes with transformation of its topography. There are Prior Environmental Review(PER) for district designation and Environmental Impact Assessment(EIA) before approval on development plans. PER is implemented after developing a residential land development plan and EIA is implemented after completing a detail design. As the result, many of residential land development projects are passive to reduce potential environmental problems on the designated sites. Object of this study is to construct an evaluation system on alternatives in the early step of site designation for implementing residential land development projects with environment-friendly and sustainable way. For this, alternative evaluation model is constructed by using Fuzzy Inference and Analytic Hierarchy Process(AHP) method based on Environmental Evaluation Factors of residential land development project, which are proposed in the precedent research. If a decision maker evaluates environment damage by ten-point method, the point is transformed Environmental Performance(EP) by Fuzzy Inference, and then, applying weight that is already calculated by AHP method, Total Environmental Performance(TEP) is calculated. After all, an alternative with the highest TEP is selected as the best one. Using this evaluation system, more than two alternatives of residential land development project site, which can hold location appropriateness in the early under undecided land use plan, can be evaluated quantitatively. As environmental damages, which can be generated by implementing a residential land development project, can be detected in the early step, environmental damages can be removed or reduced at the source.

• Journal of the Korean Electrochemical Society
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• v.15 no.4
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• pp.216-221
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• 2012

Electrochemical reduction of carbon dioxide has been widely studied by many scientists and researchers. Recently, the production of formic acid, which is expensive but highly useful liquid material, is receiving a great attention. However, difficulties in the electrochemical reduction process and analyzing methods impede the researches. Therefore, it is important to design an adequate system, develop the reduction process and establish the analyzing methods for carbon dioxide reduction to formic acid. In this study, the production of formic acid through electrochemical reduction of carbon dioxide was performed and concentration of the product has been analyzed. Large scale batch cell with proton exchange membrane was used in the experiment. The electrochemical experiment has been performed using a series of metal catalysts. Linear sweep voltammetry (LSV) and chronoamperometry were performed for carbon dioxide reduction and electrochemical analysis using silver chloride and platinum electrode as a reference electrode and counter electrode, respectively. The concentration of formic acid generated from the reduction was monitored using high performance liquid chromatography (HPLC). The results validate the appropriateness and effectiveness of the designed system and analyzing tool.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.91-105
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• 2016

Carbon Nanotube Field-Effect Transistors (CNTFETs) have been studied as candidates for post Si CMOS owing to the better electrostatic control and high mobility. To enhance the immunity against short - channel effects (SCEs), the novel channel and gate engineered architectures have been proposed to improve CNTFETs performance. This work presents a comprehensive study of the influence of channel and gate engineering on the CNTFET switching, high frequency and circuit level performance of carbon nanotube field-effect transistors (CNTFETs). At device level, the effects of channel and gate engineering on the switching and high frequency characteristics for CNTFET have been theoretically investigated by using a quantum kinetic model. This model is based on two-dimensional non-equilibrium Green's functions (NEGF) solved self - consistently with Poisson's equations. It is revealed that hetero - material - gate and lightly doped drain and source CNTFET (HMG - LDDS - CNTFET) structure can significantly reduce leakage current, enhance control ability of the gate on channel, improve the switching speed, and is more suitable for use in low power, high frequency circuits. At circuit level, using the HSPICE with look - up table(LUT) based Verilog - A models, the impact of the channel and gate engineering on basic digital circuits (inverter, static random access memory cell) have been investigated systematically. The performance parameters of circuits have been calculated and the optimum metal gate workfunction combinations of ${\Phi}_{M1}/{\Phi}_{M2}$ have been concluded in terms of power consumption, average delay, stability, energy consumption and power - delay product (PDP). In addition, we discuss and compare the CNTFET-based circuit designs of various logic gates, including ternary and binary logic. Simulation results indicate that LDDS - HMG - CNTFET circuits with ternary logic gate design have significantly better performance in comparison with other structures.