• Title/Summary/Keyword: Self Production

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Self-assembly of Fine Particles Applied to the Production of Antireflective Surfaces

  • Kobayashi, Hayato;Moronuki, Nobuyuki;Kaneko, Arata
    • International Journal of Precision Engineering and Manufacturing
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    • v.9 no.1
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    • pp.25-29
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    • 2008
  • We introduce a new fabrication process for antireflective structured surfaces. A 4-inch silicon wafer was dipped in a suspension of 300-nm-diameter silica particles dispersed in a toluene solution. When the wafer was drawn out of the suspension, a hexagonally packed monolayer structure of particles self-assembled on almost the complete wafer surface. Due to the simple process, this could be applied to micro- and nano-patterning. The self-assembled silica particles worked as a mask for the subsequent reactive ion etching. An array of nanometer-sized pits could be fabricated since the regions that correspond to the small gaps between particles were selectively etched off. As etching progressed, the pits became deeper and combined with neighboring pits due to side-etching to produce an array of cone-like structures. We investigated the effect of etching conditions on antireflection properties, and the optimum shape was a nano-cone with height and spacing of 500 nm and 300 nm, respectively. This nano-structured surface was prepared on a $30\;{\times}\;10-mm$ area. The reflectivity of the surface was reduced 97% for wavelengths in the range 400-700 nm.

Autonomous Guided Vehicle Control Using SOC Genetic Algorithm (적응적 유전자 알고리즘을 이용한 무인운송차의 제어)

  • Jang, Bong-Seok;Bae, Sang-Hyun;Jung, Heon
    • Journal of Internet Computing and Services
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    • v.2 no.2
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    • pp.105-116
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    • 2001
  • According to increase of the factory-automation's(FA) in the field of production, the autonomous guided vehicle's(AGV) role is also increased, The study about an active and effective controller which can flexibly prepare for the changeable circumstance is in progressed. For this study. the research about ac1ion base system to evolve by itself is also being actively considered In this paper. we composed an ac1ive and effective AGV fuzzy controller to be able to do self-organization, For composing it. we tuned suboptimally membership function using genetic algorithm(GA) and improved the control efficiency by the self-correction and generating the control rules. self-organizing controlled(SOC) fuzzy controller proposed in this paper is capable of Self-organizing by using the characteristics of fuzzy controller and genetic algorithm. It intuitionally controls AGV and easily adapts to the circumstance.

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Autonomous Guided Vehicle Control Using GA-Fuzzy System (GA-Fuzzy 시스템을 이용한 무인 운송차의 제어)

  • 나영남;손영수;오창윤;이강현;배상현
    • The Transactions of the Korean Institute of Power Electronics
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    • v.2 no.4
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    • pp.45-55
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    • 1997
  • According to the increase of factory-automation in the field of production, the importance of autonomous guided vehicle's(AGV) role is also increased. The study about an active and effective controller which can flexibly prepare for the changeable circumstance is in progressed. For this study, the research about action base system to evolve by itself is also being actively considered. In this paper, we composed an active and effective AGV fuzzy controller to be able to do self-organization. For composing it, we tuned suboptimally membership function using genetic algorithm(GA) and improved the control efficiency by the self-correction and generating the control rules. Self-organizing controlled(S0C) fuzzy controller proposed in the paper is capable of self-organizing by using the characteristics of fuzzy controller and genetic algorithm. It intuitionally controls AGV and easily adapts to the circumstance.

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A case study of problem-based learning (PBL) in classes (PBL을 활용한 <드레이핑> 교과 수업사례 및 학습효과 연구)

  • Kang, Yeo Sun
    • The Research Journal of the Costume Culture
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    • v.29 no.3
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    • pp.346-360
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    • 2021
  • Universities have recently introduced problem-based learning (PBL) to various subjects to enhance problem-solving skills (including self-directed learning and small-group learning) required in industry. The PBL module was applied to the personal production process in a draping class. A study was based on a questionnaire after conducting two PBL modules with a group of students. Each PBL module included 'design analysis', 'presentation of flat sketch and draping plan', 'discussion of the plan', 'evaluation of the draping result and correcting the problem', and 'final evaluation of the completed project'. Results showed that satisfaction with the PBL method and its activities was higher than satisfaction with existing teaching methods. In particular, among the various components, the 'design analysis' and 'the presentation step of flat sketch and draping plan' stages were more helpful to students compared to small-group discussion. Moreover, the effects of PBL were observed through student reflection essays, in which students suggested that PBL was very effective in enhancing problem-solving through self-directed and small-group learning. Despite the overall satisfaction with PBL, students expressed some minor difficulties associated with awkwardness with a novel learning method, lack of diverse perspectives among each group, and poor communication skills. Therefore, the study shows that PBL is highly likely to be useful to students when they are solving pattern drafting problems and making samples through self-directed learning and small-group learning.

Effect of Acid Leaching Conditions on the Properties of Cr Powder Produced by Self-propagating High-temperature Synthesis (자전연소합성법을 이용한 Cr 분말 제조시 산세조건에 따른 물성평가)

  • YongKwan Lee;YeongWoo Cho;ShinYoung Choi;SungGue Heo;Ju Won;KyoungTae Park;MiHye Lee;JaeJin Sim
    • Journal of Powder Materials
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    • v.30 no.3
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    • pp.233-241
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    • 2023
  • In this study, we evaluated the effects of acid leaching on the properties of Cr powder synthesized using self-propagating high-temperature synthesis (SHS). Cr powder was synthesized from a mixture of Cr2O3 and magnesium (Mg) powders using the SHS Process, and the byproducts after the reaction were removed using acid leaching. The properties of the recovered Cr powder were analyzed via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), particle size analysis (PSA), and oxygen content analysis. The results show that perfect selective leaching of Cr is challenging because of various factors such as incomplete reaction, reaction kinetics, the presence of impurities, and incompatibility between the acid and metal mixture. Therefore, this study provides essential information on the properties under acidic conditions during the production of high-quality Cr powder using a self-propagating high-temperature synthesis method.

Effects of surface materials of self-draining beds on cattle behavior in a temperate climate

  • Liu, Ping;Guo, Lulu;Zhang, Fulan;Li, Lin;Mao, Huaming;Gu, Zhaobing
    • Asian-Australasian Journal of Animal Sciences
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    • v.33 no.11
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    • pp.1866-1872
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    • 2020
  • Objective: The objective of the present experiment was to construct self-draining beds to keep surface bedding materials clean and dry for beef cattle comfort in a temperate climate. Methods: In Experiment 1, a self-draining bed was covered with sand at depths of 10 cm (S-10a), 15 cm (S-15), and 20 cm (S-20) respectively. In Experiment 2, self-draining beds of different sizes were covered with 10 cm of sand (S-10b) and wood shavings (WS) at depths of 15 cm and 20 cm (WS-15 and WS-20). Fifteen cattle were engaged to evaluate the comfort of self-draining beds covered with different bedding materials. Results: No cattle lay in the feed alley and cattle spent more time lying on S-10a than S-15 or S-20 in Experiment 1 (p<0.01). No difference in lying time was detected between S-15 and S-20 (p>0.05). In Experiment 2, no cattle selected the feed alley as the lying area. Cattle preferred WS-15 as the lying area and time spent lying on WS-20 was slightly higher than on S-10b (p<0.05). Feces weight was higher in the feed alley than in the different bedding areas in both Experiments 1 and 2 (p<0.01). Conclusion: Sand-bedding depth at 10 cm and WSs at 15 cm above the self-draining bed can provide for the lying comfort of beef cattle. Design of a special feed alley to hold most of the feces to keep bedding materials clean and dry is desirable for organic beef cattle in a loose barn.

Estimation of Carbon Emissions and Energy Self-Sufficiency in Sewage Treatment plant's Improvement by using Life Cycle Management Tool (LCM 기법을 이용한 하수처리장 개선에 따른 탄소배출량 및 에너지 자립율 평가)

  • Moon, Jin-Young;Park, Ji-Hyoung;Hwang, Yong-Woo;Park, Kwang-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.2
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    • pp.223-232
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    • 2013
  • In this study, carbon emissions and energy consumption were evaluated to establish a design strategy which has low energy consumption and carbon emission production, by using life cycle energy (LCE) and life cycle $CO_2(LCCO_2)$ calculation methods in life cycle management(LCM) tools. After improvement design projects, the energy consumption and $CO_2$ emission were calculated and compared in three sewage treatment plants (STPs), which are A STP, B STP, and C STP. The reduction of carbon emissions was 28,020.1 ton $CO_{2-}e/yr$, 37,399.6 ton $CO_{2-}e/yr$ and 8,788.3 ton $CO_{2-}e/yr$, respectively. Production of energy was 792 TOE/yr, 1,235 TOE/yr and 1,023 TOE/yr, respectively. As a result, the estimation of energy and energy self-sufficiency was 5.1 %, 14.5 % and 23.5 %, respectively. The result of this study shows the LCM can be contributed to establish strategy for energy and carbon emission reduction in sewage treatment plants.

Categorization of Competencies and Description of Job Informations for Dietitians in Employee Foodservice by Wdorker-oriented Job Analysis Methodology (직영 및 위탁 사업체 급식소 영양사에 대한 작업자 지향적 직무분석(제 2 보) : 요인분석에 의한 직무수행 특성 영역 및 직무정보 기술)

  • 차진아;양일선;유태용
    • Korean Journal of Community Nutrition
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    • v.2 no.4
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    • pp.605-615
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    • 1997
  • The job characteristics and competencies of 285 dietitians in employee foodservices were investigated by worker-oriented job analysis methodology. The purposes of this study were to : a) determine the knowledge, abilities, skills and other characteristics(KASO) needed for dietitians in two types of employee foodservice groups(self-operated vs. contracted), b) categorize KASO items by factor analysis and c) provide job information and job descriptions for dietitians in employee foodservices. The job analysis questionnaire was consisted of questions concerning the 134 KASO items. The questionnaire was mailed to 250 dietitians who are members of The Korean Dietetic Association Practice Group in self-operated foodservices(group A) and 250 dietitians who are employed in contracted foodservice companies(group B). Completed questionnaires were received from 285 dietitians(121 in self-operated, 164 in contracted) ; with response rate of 57%. Statistical data analysis was completed using the SPSS/win and the SAS/win packages. The results of this study can be summarized as follows. 1) Through factor analysis, the 134 KASO items were regrouped into 6 categories :‘primary dietetic tasks concerning menu management and administrative work regarding merchants’, ‘primary dietetic tasks concerning procurement and purchasing of food and supplies and meal production and service control’, ‘primary dietetic tasks concerning facility, sanitation and safety control’, ‘secondary dietetic tasks concerning nutrition education and research’, ‘secondary dietetic tasks concerning foodservice operation management’and‘human attributes’. 2) Analysis of the total scores(average scores of degree of frequency, importance and entry requirements of KASO items within 6 categories), group A showed high priorities placed on‘human attributes’, ‘procurement and purchasing of food and supplies and meal production and service control’, ‘menu management and administrative work regarding merchants’, ‘whereas group B showed high priorities placed on’‘human attributes’, ‘foodservice operation management’. (Korean J Community Nutrition 2(4) : 605-615, 1997)

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Experimental evaluation of the performance of self-compacting concrete contains nano clay and nano egg shell

  • Hilal, Nahla N.;Hadzima-Nyarko, Marijana
    • Advances in concrete construction
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    • v.13 no.5
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    • pp.349-360
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    • 2022
  • The rising prices of landfills and the lack of cement production are motivating researchers to be more interested in using wastes to produce concrete mixtures materials. The use of waste materials such as eggshell and matakoline waste not only reduces landfill costs and space, but also reduces the cost of cement production for the concrete mixture. However, recycling waste materials has become critical in order to effectively manage environmental sustainability. The purpose of this paper is to investigate the appropriate properties of self-compacting concrete (SCC) by incorporating waste materials such as crushed ceramics as coarse aggregate and nano egg shell (NES) and nanoclay (NC) as cement replacements. Fresh properties of SCC, such as segregation, flow time and diameter, V-funnel, H2/H1 ratio, and fresh unit weight of concrete mixtures, as well as hardened properties, such as 7, 14, and 28 days compressive strength and 28 and 90 days flexural strength, were measured for this purpose. The presence of NC in the SCC mixture enhanced the compressive strength of the concrete when 5% of NES was added or in the case without the addition of NES compared to the control mixture. The flexural strength enhanced with the incorporation of NC in the SCC increased the flexural strength of the concrete compared to the control mixture, but the incorporation of 5% of NES decreased the flexural strength compared to the mixtures with NC. These results prove the possibility of using crushed ceramics as the coarse aggregate, and NES and NC as substitutes for 5, 7, and 10% of the cement in SCC, because the properties of such SCC in hardened and fresh states are satisfactory.

Growth characteristics of halophytes and forage crops under salt concentrations

  • Jeong, Jae-Hyeok;Hwang, Woon-Ha;An, Sung-Hyun;Jeong, Han-Yong;Lee, Hyeon-Seok;Baek, Jung-Sun;Choi, Kyung-Jin;Lee, Geon-Hwi;Chung, Nam-Jin;Yun, Song Joong
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.355-355
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    • 2017
  • South Korea is largely dependent on imports of forage crops. In order to raise the self-sufficiency rate of forage crops, it is necessary to cultivate forage crops in 135,100 ha reclaimed land of South Korea. This study was conducted to investigate the growth of halophytes and forage crops in order to search for stable plants on reclaimed land. The plants were cultured in Hoagland solution and grown at 0%, 0.5%, 1.0% and 2.0% of salt concentrations. Plants with good growth at 0.5% of salt concentration were halophytes such as Suaeda asparagoides and Salsola komarovii. Salicornia herbacea and Suaeda maritima showed good growth at 2.0% salinity, and Suaeda maritima showed stable growth at all of salt concentrations. In conclusion, Suaeda asparagoides showed the best growth at 0.5% of salt concentration and was considered the most biomass at reclaimed land in Korea with less than 0.5% of salt concentration.

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