• KSBB Journal
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• v.23 no.6
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• pp.504-508
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• 2008

The objectives of this study were to develope the economical process for bioethanol production from domestic triticale and investigate optimal fermentation conditions such as temperature, time, and enzyme concentration used to pre-treatment process. Triticale mash, containing 148 g of total sugar per 1 L of mash, was fermented with Saccharomyces cerevisiae CHY1011 at $33^{\circ}C$. Fermentation of mash supplemented with enzyme was completed within 48-60 hours, and the ethanol yield was 410.9 L/tonne of dry base. On the other hand, fermentation of mash without enzyme addition was completed within 36-48 hours, but the ethanol yield was 342.2 L/tonne of dry base. For optimal bioethanol production from triticale, viscosity reduction enzyme was added in the pre-treatment process, and the fermentation rate of triticale was 92.0-94.2%. In addition, the results showed that bioethanol production of triticale by low-temperature pre-treatment would provide higher ethanol production efficiency and lower operating costs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.82-88
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• 2008

This paper describes the influence of the bridge formed between electrodes by electrolyte for tracking process. Electrolytes is made by IEC(International Electrotechnical Commission) 60589, NaCl added to deionized water as each 1, 3, 5[wt%]. The used test equipment is made according to KS(Korean Industrial Standard) C IEC 00112. It is investigated voltage, current, value of resistance and thermal image when bridge formed between electrodes on tracking process. As a result, as conductivity of electrolyte gets bigger as Joule's heat on bridge also gets bigger. But It is not over electrolyte's boiling point due to evaporation heat of electrolyte. However as conductivity of electrolyte gets bigger as the necessary time of dry band gets shorter. So dry band is existed more long time between ahead of droplet to next droplet and discharge chance at dry band gets much. Therefore tracking process gets faster.

• Journal of Radiation Industry
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• v.18 no.1
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• pp.43-52
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• 2024

Currently, there are no interim storage facilities and permanent disposal facilities in Korea, so all spent nuclear fuels are temporarily stored. However, the temporary storage facility is approaching saturation, and as a measure to this, the 2nd Basic Plan for the Management of High-Level Radioactive Waste presented an operation plan for dry interim storage facilities and dry temporary storage facilities on the NPP on-site. The dry storage can be operated in various ways, and to select the optimal dry storage method, the reduction of exposure for workers must be considered. Accordingly, it is necessary to develop a worker exposure scenario according to the dry storage method and evaluate and compare the radiological impact for each method. The purpose of this study is to develop an exposure scenario for workers transporting spent nuclear fuel by dry storage method. To this end, first, the operation procedure of the foreign commercial spent nuclear fuel dry storage system was analyzed based on the Final Safety Analysis Report (FSAR). 1) the concrete overpack-based system, 2) the metal overpack-based system, and 3) the vertical storage module-based system were selected for analysis. Factors were assumed that could affect the type of work (working distance, working hours, number of workers, etc.) during transportation work. Finally, the work type of the processes involved in transporting spent nuclear fuel by dry storage method was set, and an exposure scenario was developed accordingly. The concrete overpack method, the metal overpack method, and the vertical storage module method were classified into a total of 31, 9, and 23 processes, respectively. The work distance, work time, and number of workers for each process were set. The product of working hours and number of workers (Man-hour) was set high in the order of concrete overpack method, vertical storage module method, and metal overpack method, and short-range work (10 cm) was most often applied to the concrete overpack method. The results of this study are expected to be used as basic data for performing radiological comparisons of transport workers by dry storage method of spent nuclear fuel.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6D
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• pp.615-622
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• 2012

The aim of shotcrete is to increase the bearing capacity and to protect the excavated surface from erosion by preventing falling of rock mass. Shotcreting method is divided into two types as dry process and wet process. Since 1997, wet process method has been used more frequently than dry process method in field works. The failure to bond, so called rebound, occurs in many case during shotcrete works. The excess amount of rebound has a significant effect on the total construction cost. For example, material and craft-man cost increases, the shooting time delays due to deceleration of work execution stage, work efficiency of craft-man decreases and additional cost to remove the muck generates. In this study, therefore, the experimental analysis of rebound amount and strength was conducted by analyzing the actual construction data for wet process type of shotcreting method upon accelerator contents. Also, the effective and rational method was suggested, which can be actually implemented in the Korea construction sites.

• Textile Coloration and Finishing
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• v.20 no.3
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• pp.18-24
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• 2008

The purpose of this study is to develop the dyeing method with dry leaves of indigo plant. Coloring matter was extracted from dry leaves of indigo plant with hot sodium hydroxide solution. The extract was reduced with sodium dithionite, and it was used for dyeing cotton fabrics under various conditions. UV-visible absorption spectra of extract, reduction rate of extracts by reducing agent, and the surface color of dyed cotton, lightfastness were examined. For the initial 20 minutes, the absorbance of indigo solution rapidly decreased. However, several hours later, the decreasing rate retarded. By repeating the dyeing process, the shade looked deeper and deeper. At $30-40^{\circ}C$, the value of K/S reached the highest point. The concentration of indigo solution in dye bath seemed to playa critical role for the reaction of the reducing agent. It was observed that the surface color of cotton fabrics was getting bluish and its degree of value and chroma seemed slightly decreased as the K/S value was increasing. The lightfastness was clearly enhanced by increasing the K/S value.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.5
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• pp.583-594
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• 2003

Ozone is an important atmospheric pollutant that is occurred in tropospheric chemical process and it also affects the human health and plants. For a correct application of abatement strategies for ozone, it is necessary to understand the factors that control atmospheric ozone removal by dry deposition processes. The present study investigates the numerical simulation of the dry deposition velocity (V$^{d}$ ) obtained from PNU/DEM (Pusan National University Deposition Model). PNU/DEM includes seasonal categories, meteorological factors, surface properties and land-use types and proposes for an accurate numerical computation. And, this study examines the ability of the PNU/DEM to compute V$_{d}$ of ozone over water surfaces and evaluates PNU/DEM by comparing its estimated V$_{d}$ to past observed V$_{d}$ over water. The parametrization was found to yield V$_{d}$ values generally in good agreement with the observations for the deciduous forest and the coniferous forest. Ozone is removed slowly at wet surface or water due to its low water solubility. Therefore V$_{d}$ values over water were lower than Vd values over the other surfaces. Comparison of PNU/DEM simulated V d values to observations of ozone V$_{d}$ that have been reported in the literature implies that PNU/DEM produces realistic results.

• Journal of the Korean Society of Combustion
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• v.13 no.4
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• pp.47-53
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• 2008

The reaction mechanism of methane dry reforming has been investigated using an arc-jet reactor. The effects of input power, $CO_2/CH_4$ and added $O_2$ were investigated by product analysis, including CO, $H_2$, $C_{2}H_{Y}$ and $C_{3}H_{Y}$ as well as $CH_4$ and $CO_2$. In the process, input electrical power activated the reactions between $CH_4$ and $CO_2$ significantly. The increased feed ratio of the $CO_2$ to $CH_4$ in the dry reforming does not affect to the $CH_4$ conversion. but we could observe increase in CO selectivity together with decreasing $H_2$ generation. Added oxygen can also increase not only CO selectivity but also $CH_4$ conversion. However, hydrogen selectivity was decreased significantly due to a increased $H_{2}O$ formation.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.78-83
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• 2010

On the paved track, the ballast is used as aggregate for the filling layer using the pre-packed concrete technique. The most important condition of aggregate is adhesive strength with mortar. To satisfy this condition, surface of aggregate should be cleaned by water or others. In a paved-track method to be introduced domestically, an environment-friendly dry-washing technology which will replace the water-washing method has been developed. A dry-washing method was designed to blast the crushed weight material with a diameter of 0.3~0.5mm at high pressure to peel the surface of the aggregate. The study was intended to enhance the washing efficiency of dry-blasting technology and to that end, the tests including blasting material, content of fine aggregate depending on time elapsed, content of chloride, LA abrasion rate and compressive strength were conducted to recommend the efficient washing material and the process.

• Structural Engineering and Mechanics
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• v.65 no.2
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• pp.203-211
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• 2018

This paper introduces the development process of NCC(New Concrete Cutting) system and analyzes first verification test. Based on the first verification test results, some problems of NCC system have been newly modified. We carry out the second verification test. We tried to verify cutting performance and dust control efficiency of NCC system through the cutting test of concrete bridge piers. In particular, this verification test strives to solve the problem of concrete dust, which is the biggest problem of dry cutting method. The remaining dust problems in cutting section tried to solve through this verification test. This verification test of the NCC system shows that the dust problem of dry cutting method is closely controlled and solved. In conclusion, the proposed NCC method is superior to the dry cutting method in all aspects, including cutting performance, dust vacuum efficiency and cooling effect. The proposed NCC system is believed to be able to provide eco-friendly cutting technology to various industries, such as the removal of the SOC structures and the dismantling of nuclear plants, which have recently become a hot issue in the field of concrete cutting.

• Geomechanics and Engineering
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• v.16 no.3
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• pp.321-329
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• 2018

Classic braced walls use struts and wales to minimize ground movements induced by deep excavation. However, the installation of struts and wales is a time-consuming process and confines the work space. To secure a work space around the retaining structure, an anchoring system works in conjunction with a braced wall. However, anchoring cannot perform well when the shear strength of soil is low. In such a case, innovative retaining systems are required in excavation. This study proposes an innovative earth-retaining wall that uses in situ soil confined in dual sheet piles as a structural component. A numerical study was conducted to evaluate the stability of the proposed structure in cohesionless dry soil and establish a design chart. The displacement and factor of safety of the structural member were monitored and evaluated. According to the results, an increase in the clearance distance increases the depth of safe excavation. For a conservative design to secure the stability of the earth-retaining structure in cohesionless dry soil, the clearance distance should exceed 2 m, and the embedded depth should exceed 40% of the wall height. The results suggest that the proposed method can be used for 14 m of excavation without any internal support structure. The design chart can be used for the preliminary design of an earth-retaining structure using in situ soil with dual steel sheet piles in cohesionless dry soil.