• Title/Summary/Keyword: improvement of durability

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An Empirical Study on Air Force Mechanic Parka to Improve the Functionality (공군 정비파카의 기능성 개선을 위한 실태조사)

  • Lee, Sung-Ji;Nam, Yun-Ja;Choi, Hee-Eun;Cho, Young-Lim
    • Fashion & Textile Research Journal
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    • v.13 no.5
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    • pp.759-768
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    • 2011
  • This study is designed to understand current wearing conditions of air force mechanic parkas and evaluate their functionality by examining the wearing conditions and wearers' subjective assessment. By doing so, it also intends to identify issues that require improvements; and to provide basic data for future development of air force mechanic parkas. A survey was conducted as a study methodology, and the collected 1,628 questionnaires were analyzed. Findings of this study are as follows. 1. In the usability assessment, it was found that visibility of body sides was needed to be enhanced since reflective tapes were attached only to the front and back of the body; pockets were too big, but not convenient to keep mechanic tools; the design of hiding hood was not suitable for water-proof clothing; and a new design of size-controllable hood was called for since the hood blocked eye sight. With respect to the fabric, dissatisfaction was identified with durability, cold-proof and fire-proof features. 2. In the mobility assessment, respondents showed low satisfaction with collar heights and neck girths. Mobility score was over moderate level on average, except the parka length that obstructs wearers' movement, and neck and collar size. 3. In the wearability assessment, respondents presented moderate satisfaction with pleasantness, weight, pressure and dampness. However, insulation was found unsatisfactory. Based on the result, this study proposed improvement plans on design, pattern and fabric; and is expected to serve as basic data for developing more effective and functional air force mechanic parkas.

An Experimental Study on the Properties of Concrete with Regional Fine Aggregate Properties and Modulation of Fine Aggregate Ratio (지역별 잔골재특성 및 잔골재율 조정에 의한 콘크리트 특성에 관한 실험적 연구)

  • Yoo, Seung-Yeup;Lee, Sang-Rae;Lee, Bum-Suck;Song, Yong-Soon;Kang, Suck-Hwa
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.465-468
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    • 2008
  • This study investigated the best condition when mixed sand with a river and crushed sand was used though the experiment for the properties of the concrete corresponding to the control of fine aggregate ratio to apply the mixed sand and properties of the fine aggregate at the ready-mixed concrete factory on Yeongnam and Honam. The physical properties of Yeongnam and Honam is satisfied with KS F 2526 and KS F 2527 except fineness modulus and passing amount of 8mm sieve. And, the mixed sand above two types which were incongruent to use individually was being used at each factory, and it was managed in accordance with KS. The flowabillity of the mixture proportion of concrete which was estimated by method of unit volume weight according to the fine aggregate ratio at each factory on Yeongnam and Honam was higher than existing mixture proportion. It was analyzed that the residual water due to decline of the surface area caused by reducing fine aggregate ratio was increased relatively. Accordingly, it was considered that the effect on the economic mixture proportion and improvement of durability might be possible.

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A Study on Cognition Analysis for Effective Management of Suspended Construction Building (공사 중단 건축물의 효율적 관리를 위한 인식 분석 연구)

  • Suhr, Myong-Suk
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.2
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    • pp.131-137
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    • 2019
  • The purpose of this study is to investigate the perception of buildings suspended from construction and to analyze the problems that are inherent and effective in the management of public officials and residents in the area where construction is suspended. There are 63 buildings in the Gangwon area, 16% of which are occupied by the whole area. 31% of the apartment houses are occupied the most, and 10 years or more is suspended. 241 of them accounted for 62%. In order to efficiently manage buildings that are suspended from construction, protection measures should be taken to ensure safety and prevent crime through periodic and continuous management of facility grade management that conforms to the special act on safety and maintenance of facilities. Effective support for budget and personnel is required for efficient management of construction suspended.

The development of fuel processor for compact fuel cell cogeneration system (소형 열병합 연료전지 연계형 연료처리시스템 개발)

  • Cha, Jung-Eun;Jun, Hee-Kwon;Park, Jung-Joo;Ko, Youn-Taek;Hwang, Jung-Tae;Chang, Won-Chol;Kim, Jin-Young;Kim, Tae-Won;Kim, In-Ki;Jeong, Young-Sik;Kal, Han-Joo;Yung, Wang-Rai;Jung, Woon-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.323-327
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    • 2009
  • To extract hydrogen for stack, fuels such as LPG and LNG were reformed in the fuel processor, which is comprised of desulfurizer, reformer, shift converter, CO remover and steam generator. All elements of fuel processor are integrated in a single package. Highly active catalysts (desulfurizing adsorbent, reforming catalyst, CO shift catalyst, CO removal catalyst) and the various burners were developed and evaluated in this study. The performance of the developed catalysts and the commercial ones was similar. 1 kW, 5 kW class fuel processor systems using the developed catalyst and burner showed efficiency of 75 %(LHV, for LNG). The start-up time of the 1 kW class fuel processor was less than 50 minutes and its volume including insulation was about 30 l. The start-up time of 3 kW and 5 kW class fuel processors with the volume of 90 l and 150 l, respectively, was about 60 minutes. In the case of LPG fuel, efficiency, volume and start-up time of 1kW class fuel processor showed 73 %(LHV), < 60 l and < 60 min, respectively. Advanced fuel processor showed more highly efficiency and shorter start-up time due to the improvement of heat exchanger and operating method. 1 kW and 3 kW class fuel processors have been evaluated for reliability and durability including with on/off test of developed catalysts and burner.

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Improvement and Evaluation of Seismic Performance of Flat Plate Slab-Column Joint Using High Ductile Fiber-Reinforced Mortar (고인성섬유 복합모르타르를 활용한 플랫 플레이트 슬래브-기둥 접합부의 내진성능 평가 및 개선)

  • Ha, Gee-Joo;Yi, Dong-Ryul
    • Journal of the Korea Concrete Institute
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    • v.24 no.3
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    • pp.341-349
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    • 2012
  • Recently, as structures in Korea and other countries become much taller, larger, and more specialized, concrete used for constructions of these structures is required to have high performance characteristics. Especially, seismic performance of concrete must be improved to resist cyclic loading from earthquakes. Consequently, this study was performed to focus on developing optimal mixtures of high ductile fiber reinforced mortar with high ductility and durability, which have good serviceability, stability and reliability performances. Eventually, this material is expected to improve seismic performance of concrete structures such as load carrying capacity, ductility capacity, and energy dissipation capacity when applied to critical regions of flat plate slab-column joint. Ultimately, this research is intended to develop a material for basic designs and practical constructions of reinforced concrete structures. Test results showed that the maximum load carrying capacity, the ductility capacity, and the energy dissipation capacity of the test specimens titled RCFPP series were increased by 15%~34%, by 33%~37%, and by 2.14 times, respectively, compared to those of the standard specimen titled SRCFP.

Study on the Technological Levels for the Industries Manufacturing the Machinery and Equipment for Livestock Production Facilities (축산시설의 기계 및 설비 산업의 기술 수준 분석 연구)

  • 장동일;장홍희
    • Journal of Animal Environmental Science
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    • v.2 no.1
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    • pp.13-25
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    • 1996
  • This study was conducted to analyze the technological levels of the domestic industries manufacturing the machinery and equipment for livestock production facilities and to lay out a scheme for upgrading the technical improvement. The results of this study are as follows : 1 . According to the study results, the technological levels of the domestic industries for livestock production facilities lag far behind those of the advanced countries in this field. 2. It was found that the ratio engaged in the areas of R&D was 10.7% and lower than that engaged in the other areas and the ratio of junior college graduated engineers engaged in the areas of research and design was 44.4%. Therefore, the amounts of investment for the areas of R&D and design should be increased. 3. In the design area, it was found from the study that the most weakness technologies which should be developed in near future were the universal harvester and the mechanical designing. Therefore, the multipurpose universal harvester suitable to the domestic farmland conditions should be developed and strength, hardness, and durability of materials in the mechanical designing should be improved.

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Evaluating the Durability of Concrete Combined with Ground Granulated Blast Furnace Slag using Electrolysis Alkaline Aqueous as Mixing Water (전기분해 알칼리수를 배합수로 사용한 고로슬래그 미분말 혼입 콘크리트의 내구성)

  • Jeong, Su-Mi;Kim, Ju-Sung;Park, Sun-Gyu
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.4
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    • pp.349-358
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    • 2023
  • This research aimed to enhance the initial strength of concrete that is mixed with ground granulated blast furnace slag, as well as to fortify its resistance to carbonation and chloride ion permeation. To achieve this, alkaline aqueous, produced through the electrolysis of potassium carbonate, was employed as the mixing water in the preparation of concrete. To substantiate the increment in initial strength, compressive strength measurements of the concrete were executed. Additionally, an accelerated carbonation test and a chloride ion permeation resistance test were undertaken. The results confirmed that the initial strength of the concrete, which utilized electrolysis alkaline aqueous as mixing water, exhibited an improvement in comparison to concrete mixed with conventional water. It was also verified that both carbonation resistance and chloride ion permeation resistance showed enhancements.

An Aging Measurement Scheme for Flash Memory Using LDPC Decoding Information

  • Kang, Taegeun;Yi, Hyunbean
    • Journal of the Korea Society of Computer and Information
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    • v.25 no.1
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    • pp.29-36
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    • 2020
  • Wear-leveling techniques and Error Correction Codes (ECCs) are essential for the improvement of the reliability and durability of flash memories. Low-Density Parity-Check (LDPC) codes have higher error correction capabilities than conventional ECCs and have been applied to various flash memory-based storage devices. Conventional wear-leveling schemes using only the number of Program/Erase (P/E) cycles are not enough to reflect the actual aging differences of flash memory components. This paper introduces an actual aging measurement scheme for flash memory wear-leveling using LDPC decoding information. Our analysis, using error-rates obtained from an flash memory module, shows that LDPC decoding information can represent the aging degree of each block. We also show the effectiveness of the wear-leveling based on the proposed scheme through wear-leveling simulation experiments.

A Study on the Durability Improvement of Movable Bracket Structures (가동 브라킷 구조물의 내구 성능 향상 방안 연구)

  • Park, Yong-Suk;Seo, Jeong-Beom
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.3
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    • pp.1117-1121
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    • 2011
  • The movable bracket structure, which is an apparatus for supplying electric power to a running electric locomotive, is applied by a repeated load during the passage of the electric locomotive. Such a repeated load becomes an excitation source that causes screws constituting the movable bracket structure to be loosened. This study was conducted on the causes and countermeasures of the bolt loosening caused by the repeated vibration using a computer simulation. As the result, a simulation model was constructed to enable the dynamic analysis of the movable bracket structure. It could be found that the principal excitation frequency range for the bolt loosening of the movable bracket structure was less than 200 Hz. In addition, the bolts are prevented from being loosened by increasing stiffness of H beams. The vibration mode of a lower band bracket is found to be triggered in a frequency range between 300 and 600 Hz. And the increase in stiffness of the lower band bracket exhibits the effect to avoid the bolt loosening at a frequency range of 200 Hz or more.

Effect of Consolidation using Artificial Porous Material for Stone Cultural Property (인공 다공질체를 이용한 석조문화재 강화제의 처리효과)

  • Lee, Jae-Man;Lee, Myeong-Seong;Kim, Jae-Hwan;Lee, Mi-Hye
    • Journal of Conservation Science
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    • v.26 no.3
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    • pp.325-334
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    • 2010
  • In order to clarify the effect of consolidant, the artificial porous material with low intensity was manufactured using granite powder and Portland cement. We have prepared four kinds of alkoxysilane system consolidants, a acrylic resin and a epoxy resin and investigated about characteristics before and after consolidation. As a result of the research, Silres BS OH 100 was effective for density and surface hardness. SS-101 with hydrophobicity and Site SX-RO with hydrophilicity had the good durability over salts weathering. On the other hand, Syton HT-50 and Paraloid B72 were easily destructed by salt weathering because they were concentrated on surface area by the low penetration depth. Araldite 2020 was the most effective consolidant for improvement of physical properties.