• Title/Summary/Keyword: mixing length

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A Basic Study on the Development of Backfill Material with Fly Ash and Bottom Ash of Circulating Fluid Bed Combustion (순환유동층보일러의 Fly Ash, Bottom Ash를 활용한 채움재 개발에 관한 기초연구)

  • Cho, Yong-Kwang;Lee, Yong-Mu;Nam, Seong-Young;Kim, Chun-Sik;Seo, Shin-Seok;Jo, Sung-Hyun;Lee, Hyoung-Woo;Ahn, Ji-Whan
    • Journal of the Korea Institute of Building Construction
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    • v.18 no.1
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    • pp.25-31
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    • 2018
  • In this study, the Controlled Low Strength Material (CLSM) was investigated to utilize the bottom ash and fly ash generated in the Circulating Fluidized Bed Combustor (CFBC). It was confirmed that the CFBC fly ash (CFBC-F) and CFBC bottom ash (CFBC-B) had an irregular particle shape through SEM measurement. According to the results of the hazard analysis, it was also confirmed that they were environmentally safe. In the case of mixing with CFBC-F, the unit quantity was increased. Regarding the rate of change of length, shrinkage in the range of -0.05~0.50% occurred in the air dry curing condition and expansion in the range of 0.1~0.6% in the sealed curing condition. Compressive strength was increased in the sealed curing condition compared to the air dry curing condition because there was enough moisture for hydration reaction in the long term. Therefore, the results of this study are likely be used as basic research data of mine filler materials.

An Experimental Study on the Self-Consolidating Concrete with EP Nylon Fiber (EP 나일론섬유를 혼입한 자기충전콘크리트(SCC)에 관한 실험적 연구)

  • Ryou, Jae Suk;Lee, Yong Soo;Jeon, Joong Kyu;Jeon, Chan Ki
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.1
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    • pp.159-168
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    • 2011
  • In this study, we find out the feasibility of self-consolidating concrete with EP nylon fiber. Three kinds of method were used; when length of nylon fiber is differed for the experiment to investigate usability of nylon fiber with enhanced performance by dispersing-agent coating in self-consolidating concrete, when mixing in other organic fibers (polypropylene, cellulose) and in case of Binary Blended and Ternary Blended concrete mixed with different types of mineral admixtures (blast-furnace slag and fly ash). Based on the results of the experiment described above, comparison was made on the basic properties and dynamic characteristics of general fiber reinforced concrete mixed with enhanced performance nylon fiber and SCC mixed with enhanced performance nylon fiber as a Mock-up test prior to the experiment of application to the actual structure. Considering characteristics and durability of the fresh and hardened self-compacting concrete, dynamic characteristics and durability were found to be more outstanding when using nylon fiber for the mineral admixtures used, dynamic characteristics and durability were found to be more outstanding when using blast-furnace slag.

The Properties and Production of Hand-Made Paper Made from Various Plant Fibers (식물섬유 수초지의 제조와 물성에 대한 연구)

  • Lee, Hye-Ja;Lim, Hee-Jung;Bae, Hyun-Young;Mo, Tae-Wha;Yoo, Hye-Ja;Han, Young-Sook
    • Journal of the Korean Society of Clothing and Textiles
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    • v.32 no.9
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    • pp.1366-1375
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    • 2008
  • This studies were carried out in order to develope environmentally-friendly fiber materials and substitute resources of Paper mulberry. Various plant fibers such as New Zealand flax, Indian mallow, Kuzu vine and Yucca were used as raw materials of hand-made papers. We rotted these 4 kinds of plant fibers and removed non-cellulose. After rotting, the pulping rate(%) and the length of fibers in pulps were measured. The physical characteristics of papers made of various plants fiber were investigated and the probabilities of practical use were considered. The results were as follow: The non-cellulose contents of plant fibers were $30{\sim}40%$ and those contents must be lower down to 8% to be able to manufacture the hand made papers. The lignin in pulps were removed almost and the hemicellulose were partially removed to reach up to appropriate level of the pulp rates and fiber lengths. The more hemicellulose removed, the finer fiber thickness were and rapidly the lower Hanji tensile strength were. But the tear strength of these plants of hand-made papers do not decreased so much as tensile strength. So the property of 4 types of plant fibers might be of great advantages to make hand-made papers. Both tensile and tear strengths of Hanji of New Zealand flax, Indian mallow, Kuzu vine and Yucca were higher than Paper mulberry hand-made paper. When 30% of mulberry paper were mixed, the mixing effect showed maximum. Because of the functions of all plant fiber hand-made papers showed better than those of Paper mulberry hand-made paper, 4 types of plant fibers could be substitute Paper mulberry.

Early Hardening Behavior of Natural Hydraulic Lime Paste by Multiple Light Scattering Analysis (Multiple Light Scattering 분석법을 이용한 천연수경성석회의 초기경화 거동)

  • Moon, Ki-Yeon;Cho, Kye-Hong;Cho, Jin-Sang;Hong, Chang-Woo
    • Resources Recycling
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    • v.26 no.1
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    • pp.43-50
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    • 2017
  • In the present study, the multiple light scattering method was used for analysis of early hardening behavior of natural hydraulic lime (NHL) containing inorganic additives. In order to improve the properties of self-manufactured NHL, blast furnace slag and three types of gypsum were mixed with mixing ratio, and a water/solid ratio of fresh NHL paste was fixed 0.6. The fresh pastes in flat-bottomed cylindrical glass tubes were placed in the instrument. The backscattering flux (BS) of light from fresh pastes was then periodically measured at 10 minutes intervals the entire length of the sample (55mm) at $23^{\circ}C$ for 24 hours. The rate of increase of BS, slope of a linear equation to the mean value of BS (%) as a function of hydration time, was increased from 0.02 to 0.38 BS %/hour due to addition of blast furnace slag and gypsum. In the case of addition of hemi-hydrate, BS (%) and rate of increase in BS were highest.

Study on the Change in Physical and Functional Properties of Paper by the Addition of Chitosan (키토산 섬유를 첨가한 종이의 물성 및 기능성의 변화에 관한 연구)

  • Park, Seong-Cheol;Kang, Jin-Ha;Lim, Hyun-A
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.42 no.5
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    • pp.37-46
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    • 2010
  • This study was carried out to develop new application field and obtain the basic data of mixed paper with wood pulp and chitosan fiber for producing functional paper. Two types of wood pulp, such as SwBKP and HwBKP, were mixed with chitosan fiber. Physical and optical properties, water vapor absorption, air permeability, antibacterial activity and ash were measured. And the surface morphology of manufactured paper was observed using SEM. The results are as follows. It was revealed that density, breaking length, burst index, tear index, folding endurance and brightness were reduced but water vapor absorption and air permeability were on the rise in the structural view of SwBKP according to increasing the chitosan fiber ratio. Those HwBKP added chitosan fiber were great not only in the strength but also water vapor absorption and air permeability except for brightness. The water vapor absorption was lower and the air permeability was higher in the HwBKP added various chitosan fiber ratios than those with no chitosan fiber. It is estimated that these properties were related with various mixed rate of chitosan fiber. Particularly, air permeability was strongly dependent on the mixed rate of chitosan fiber. The chitosan fiber has superior antibacterial property, comparing with wood fiber. Adding chitosan fiber to the wood pulp was found to have an excellent antibacterial activity, more than 90%. The ashes were determined within 0.5%. Special bonds between chitosan fiber and wood pulp was observed by SEM and it means that the chitosan fiber were combined equally in the interior of wood pulp. In conclusion, mixing wood pulp with chitosan fiber can not only improves the quality of paper but also extend the usage of paper as a functional paper by using inherent property of chitosan. After all, production of functional paper added chitosan fiber is expected for new valuable industry of paper.

Impact Analysis of Tributaries and Simulation of Water Pollution Accident Scenarios in the Water Source Section of Han River Using 3-D Hydrodynamic Model (3차원 수리모델을 이용한 한강 상수원구간 지류영향 분석 및 수질오염사고 시나리오 모의)

  • Kim, Eunjung;Park, Changmin;Na, Mijeong;Park, Hyeon;Kim, Bogsoon
    • Journal of Korean Society on Water Environment
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    • v.34 no.4
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    • pp.363-374
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    • 2018
  • The Han River serves as an important water resource for the city of Seoul, Korea and in the neighboring metropolitan areas. From the Paldang dam to the Jamsil submerged weir, the 4 water intake stations that are located for the Seoul metropolitan population were under review in this study. Therefore the water quality management in this section is very important to monitor, analyze and review to rule out any safety concerns. In this study, a 3-D hydrodynamic model, EFDC (Environmental Fluid Dynamics Code), was applied to the downstream of the Paldang Dam in the Han River, which is about 23 km in length, to determine issues related to water resource management. The 3-D grid was composed of 2,168 horizontal grids and three vertical layers. In this case, the hydrodynamic model was calibrated and verified with an observed average daily water surface elevation, water temperature and flow rate data for 3 years (2013~2015). The developed EFDC model proved to reproduce the hydrodynamics of the Han River well. The composition ratios of the noted incoming flows at the monitored intake stations for 3 years and their flow patterns in the river were analyzed using the validated model. It was found that the flow of the Wangsuk Stream depended on the Paldnag dam discharge, and it was noted that the composition ratios of the stream at the intake stations changed accordingly. In a word, the Wangsuk Stream moved mainly along the right bank of the Han River under the condition of a normal dam flow. As can be seen, when the dam discharge rate was low, the incidence of lateral mixing was often seen. The scenario analyses were also conducted to predict the transport of conservative pollutants as in the case of a chemical spill accident. Generally speaking, when scenarios were applied, the arrival time and concentration of pollutants at each intake station was thus predicted.

Growth characteristics and productivity of oyster mushroom with the addition of Artemisia annua (개똥쑥 첨가에 따른 느타리의 생육 특성 및 수량성)

  • Lee, Chan-Jung;Lee, Jung-Hoon;Min, Gyeong-Jin;Park, Hye-sung;Lee, Eun-ji
    • Journal of Mushroom
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    • v.18 no.2
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    • pp.174-177
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    • 2020
  • This study sought to determine the optimal mixing ratio of Korean cultivated Artemisia annua for production of functional oyster mushrooms. After 23 days of cultivation, mycelial growth was 12.7 cm in medium supplemented with 5% A. annua and 12.5 cm in control. Mycelial growth progressively slowed with the addition of A. annua, with barely any growth (2.1 cm) in the presence of 70% A. annua. Mycelial density was high density without significant difference between treatments. The pileus diameter was greater in the presence of A. annua than in the control, but the pileus thickness was only slightly higher compared to the control. The stipes thickness was greatest for 15% A. annua, and the length of stipes was longest at 10% A. annua, but was lower than the value of the control. The L value of the fruiting zone was highest 10% firewood, and the L value of freshwater was highest at 5% A. annua. The fruiting body yield was highest to (122 g/850 ml) in medium supplemented with 5% A. annua but markedly decreased at higher levels of A. annua.

Agronomic Effect of High Quality Compost mixed with Brown Seaweed for Environmentally Benign Organic Farming (해초 혼합 기능성 희비의 작물재배 효과)

  • 손상목
    • Korean Journal of Organic Agriculture
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    • v.10 no.2
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    • pp.95-109
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    • 2002
  • This study focussed to find out the agronomic effect of high quality compost mixed with brown seaweed and to determine the optimum mixing rate of seaweed to compost for environmentally benign organic farming. The experiment was conducted in lysimeters at Experimental Farm of Dankook University with Chinese Cabbage(Bulam #1), and the crop growth such length and width of leaf, biomass of Chinese Cabbage were checked, the content of chlorophyll, sugar, vitamin C, nitrate in outer leaf and idler leaf was determined. It was observed that nitrate content was dramatically decreased in the plot of mixture with seaweed, while biomass and content of Vitamin C were increased steeply in the plot of mixture with seaweed. The best result was gained the 0.25% mixture of brown seaweed with compost.

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A Bibliographical Study of Dock(Korean rice cake) (떡류(類)의 문헌적(文獻的) 고찰(考察) -(1670년${\sim}1943$년의 우리말 조리서를 중심으로)-)

  • Mang, Hae-Yull;Lee, Hyo-Gee
    • Journal of the Korean Society of Food Culture
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    • v.3 no.2
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    • pp.153-162
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    • 1988
  • $D{\acute{o}}ck$ (Korean rice cake) is a peculiar food of Korea made of grain. By means of cooking from, it is defined as 'Pulvberzed food of grain' $D{\acute{o}}ck$ was one of the daily food, but development of boild rice had narrowed it's use to the food of festive days and ceremonies. $D{\acute{o}}ck$ is used as a main food of all Kinds of ceremonies from one's birth to death, such as the Three seven day(a baby's twenty-first day of life), one hunderdth day, birthday, wedding, both brithday, funeral and sacrifical rites, vocational ceremonies, such as a sacrifice to spirits and a srevics for a big catch of fish. It is also used as a present and seasonal food. A large variety of $D{\acute{o}}ck$ is available and its recipe is scientific and reasonable. In this treatise, the Kinds of $D{\acute{o}}ck$ and the frequency of them, the material, the recipe, the measuring unit of material, cooking kitchen utensils and the cooking terms are studied from the books published in Korea from 1670 to 1943. 1. $D{\acute{o}}ck$ was classified as Tcbin $D{\acute{o}}ck$(steamed), Chin $D{\acute{o}}ck$(strikn), Chijin $D{\acute{o}}ck$(fried) and Salmun $D{\acute{o}}ck$(boiled), according to its way of cooking. 2. There were 122 Kinds of $D{\acute{o}}ck$, 57 were Tchin $D{\acute{o}}ck$, 35 Chin $D{\acute{o}}ck$, 20 Chijin $D{\acute{o}}ck$, and 10 Salmun $D{\acute{o}}ck$. 3. There were 34 Kinds of measuring units. Of them, 13 for volume, 4 for weight, 9 for quantity, 4 for length and 4 for the rest. 4. There were 55 Kinds of cooking Kitchen utensils but now many of them are not used because of mechanization or automation of tools of living. 5. There were 143 Kinds of cooking terms. Of them 49 for the preparing process, 25 for the mixing process, 27 for well-forming process 10 for process of getting ready to cook, 14 for heating process, 10 for cutting process, 5 for dishin process and 3 for process of soaking in sugar or honey.

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Optimum Condition of the Coir-Based Substrate for Growth of Red Pepper (Capsicum annuum L.) Plug Seedlings (코이어 혼합상토를 이용한 고추 육묘용 최적 상토개발)

  • Lee, Hyun-Haeng;Ha, Sang-Keon;Kim, Kye-Hoon
    • Korean Journal of Soil Science and Fertilizer
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    • v.40 no.5
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    • pp.369-376
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    • 2007
  • This experiment was carried out to investigate optimum conditions of coir-based substrates for the red pepper plug seedlings. Eleven different coir based substrates prepared by mixing of coir, vermiculite, rice hull, perlite, zeolite, mixed at different ratios were tested. The physical and chemical properties of the substrates were analyzed by the CEN (European committee for standardization) method. Fresh and dry weights of shoot and root, leaf area, root length, and T/R ratio (dry shoot weight/dry root weight) were determined at 55 days after sowing. The results showed that the growing media CRZ 8(coir:rice hull: vermiculite=8:1.9:0.1) and CVSZ 6(coir:silver vermiculite: zeolite=6:3.9:0.1) can successfully be used for pepper plug seedlings judging from dry weight and T/R ratio of the plug seedlings. The optimal range of total pore space, water volume, air volume, easily available water content and water buffering capacity of the coir-based growing substrates for pepper plug seedlings were in the range of 92~94%, 52~60%, 32~43%, 18~21%, and 0.9~8%, respectively.