• Title/Summary/Keyword: 일반기계

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Texture Characteristics of Soybean-Curds Prepared with Different Coagulants and Compositions of Soybean-Curd Whey (응고제를 달리하여 제조한 두부의 텍스쳐 특성과 두부순물의 성분)

  • 이선미;황인경
    • Korean journal of food and cookery science
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    • v.13 no.1
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    • pp.78-85
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    • 1997
  • To determine the optimum coagulants concentrations for preparing soybean-curds, the transmittance of soybean-curd whey using spectrophotometer has been measured. The textural properties of soybean-curds were examined by texture analyzer and sensory evaluations. The general components, oligosaccharides and amino acids in soybean-curd wheys were analyzed. Protein patterns of soybean-curd wheys comparing with soyflour and soymilk were investigated. By texture analyzer, hardness, cohesiveness, springiness, and gumminess of Cacl$_2$ soybean-curd, MgCl$_2$ soybean-curd were higher than those of CaSO$_4$ soybean-curd and GDL soybean-curd. In the sensory evaluations, CaSO$_4$ soybean-curds and GDL soybean-curds were smoother and moister than others. Glutamic acid and aspartic acid were the first two abundant amino acids in three kinds of soybean-curd wheys, but arginine was the most abundant amino acid in GDL soybean-curd whey. Total sugar content of soybean-curd wheys were about 12-13 g/l, and the main sugars among 5 kinds of sugars were sucrose and raffinose. Electrophoresis using SDS-PAGE showed that glycinin and P-conglycinin, the main proteins of soybean appeared in soy flour and soymilk, and only low molecular weight subunits appeared in soybean-curd wheys.

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Reaction Force Analysis on the Journal Bearing of Shafting System with Contra-Rotating Propeller (상반회전 프로펠러 축계 저널 베어링 반력해석)

  • Shin, Sang-Hoon;Lee, Seung-Min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.10
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    • pp.270-276
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    • 2019
  • According to the International Maritime Organization (IMO) 2020 Regulation, ships operating outside designated emission control areas (ECA) have to use low-sulfur oil with a sulfur content of 0.5% or less by January 2020. To minimize the consumption of high-priced low-sulfur oil, it is urgent to introduce efficient energy-saving devices (ESD), and contra-rotating propeller (CRP) systems are well known to be the most effective one. The shafting system that drives a CRP is composed of an inner shaft and an outer one and has a mutually influential system that is much more complex and heavier than a general shafting system. An initial design was carried out to install a CRP system for the first time in Korea. The purpose of this study is to verify whether the journal bearing meets the classification's design criteria through a bearing reaction force analysis for the classification's approval of the initial design. It is ideal for the thrust of the propeller to act on the center of the shaft, but thrust eccentricity occurs due to the uneven wake caused by the stern shape. Load conditions were applied while considering thrust eccentricity to perform the shaft analysis, and the results were compared with the classification's criteria.

Development of FCEV accident scenario and analysis study on dangerous distance in road tunnel (도로터널에서 수소차 사고시나리오 개발 및 위험거리에 대한 분석 연구)

  • Lee, Hu-Yeong;Ryu, Ji-Oh
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.6
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    • pp.659-677
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    • 2022
  • Hydrogen is emerging as a next-generation energy source and development and supply of FCEV (hydrogen fuel cell electric vehicle) is expected to occur rapidly. Accordingly, measures to respond to hydrogen car accidents are required and researches on the safety of hydrogen cars are being actively conducted. In this study, In this study, we developed a hydrogen car accident scenarios suitable for domestic conditions for the safety evaluation of hydrogen car in road tunnels through analysis of existing experiments and research data and analyzed and presented the hazard distance according to the accident results of the hydrogen car accident scenarios. The accident results according to the hydrogen car accident scenario were classified into minor accidents, general fires, jet flames and explosions. The probability of occurrence of each accident results are predicted to be 93.06%, 1.83%, 2.25%, and 2.31%. In the case of applying the hydrogen tank specifications of FCEV developed in Korea, the hazard distance for explosion pressure (based on 16.5 kPa) is about 17.6 m, about 6 m for jet fire, up to 35 m for fireball in road tunnel with a standard cross section (72 m2).

A Numerical Study on Smoke Behavior of Fishing Vessel Engine Room (어선 기관실의 연기 거동에 관한 수치해석 연구)

  • JANG, Ho-Sung;JI, Sang-Won
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.5
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    • pp.683-690
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    • 2021
  • The ventilation system of the engine room of a ship is generally installed to supply the combustion air necessary for the internal combustion engine and to remove the heat source generated in the engine room, and it must satisfy the international standard (ISO 8861) for the design conditions and calculation standards for the ventilation of the ship engine room. The response delay of the ventilation system including the fire detector is affected by the airflow formed inside the area and the location of the fire detector. In this study, to improve the initial fire detection response speed of a fire detector installed on a fishing vessel and to maintain the sensitivity of the installed detector, the smoke behavior was simulated using the air flow field inside the engine room, the amount of combustion air in the internal combustion engine, and the internal pressure of the engine room as variables. Analysis of the simulation results showed that reducing the flow rate in the air flow field and increasing the vortex by reducing the internal pressure of the engine room and installing a smoke curtain would accelerate the rise of the ceiling of the smoke component and improve the smoke detector response speed and ventilation system.

Beyond Humanism - The End of Modern Humanity and the New Transformations of Human Being (휴머니즘의 경계를 넘어서 - 근대 인간학의 종언과 인간의 새로운 변형 -)

  • Choi, Jin-Seok
    • Cross-Cultural Studies
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    • v.41
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    • pp.381-413
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    • 2015
  • This article aims to trace a historical trajectory of "Humanism" as a Modern scientific concept in the light of Michel Foucault's genealogy. Generally, we believe that Humanism is a natural and eternal idea for mankind, because no one doubts that he or she is not included in the category of a "Human Being." On the contrary, according to French philosopher Foucault, the Idea of Humanism, or anthropocentrism, appeared only in the Modern Age, from the 16th century downward. Before the Renaissance, human beings did not occupy the most important status in Nature, and only existed as natural beings. As soon as mankind was liberated from the superstitious of fear and religious dogma, the concept of "Human Being" is supplied with new meanings and values. The famous maxim, such as, "Man is the lord of creation" constitutes modern human science as an inviolable category of modernity. However, Foucault tried to illuminate the hidden sides of humanism, and gave us the strict warning on the end of the human beings, which turned out to be an object of Modern knowledge. If there would be no reason to maintain a knowledge system of Modernity, in other words, Modernity as knowledge would lose its validity and we could give up Humanism as a heavy burden. Moreover, it is very clear that we are confronted with the critical moments of radical skepticism on the meaning and value for Humanity. That means that we need to think about the new transformations of Human Beings, which will probably appear in the forms of "Non-Humans," "Machines (Deleuze & Guattari)," or "Post-Humans" etc. At the present time, we cannot know if it will be positive, or negative for mankind. We should look back at the history of Humanism from a genealogical perspective, which is why we have to investigate the conceptual trajectory of Humanism in this moment.

Numerical Study on the Characteristics of Fluid Flow and Pressure Fluctuation around Human Knuckle in Hydrogymnastics (수중 운동 시 손관절 부위의 유동 및 압력변동 특성에 대한 해석적 연구)

  • Choi, Ji-Hyun;Park, Sung-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.390-395
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    • 2019
  • Hydrogymnastics so that sufficient exercise effect can be obtained using the resistance of water has a positive effect on patients who have to receive arthritis or rehabilitation treatment. However, the studies on the effect are insufficient, and the main cause of their effects has not been unclear yet. In this study, in order to identify the main cause of the effects of Hydrogymnastics, conducted Unsteady fluid flow simulation under the same conditions as the actual environment. The analysis model based on real hands, and the pressure fluctuation applied to the knuckle was analyzed by the computational fluid method. During the underwater movement of the hands, Various sizes of vortices were generated between fingers due to skin surface velocity and flow resistance. Pressure of about -500 Pa to +500 Pa is applied by the vortex flow. Also It was confirmed that the positive pressure and the negative pressure were continuously repeated up to maximum + 2000 Pa at the minimum of -2000 Pa at the portion where the direction was changed. Pressure fluctuations with a frequency of 20 Hz to 70 Hz were added continuously for each knuckle. These continuous pressure fluctuations provide a direct massage effect on the knuckles, an It is judged that the blood circulation at the relevant part is positively affected.

A Study on the the Follow-up Analysis and the Characteristics of Exhaust Gas by Standard Mode of Chassis Dynamometer of Gasoline (가솔린 차량의 차대동력계 표준모드 별 추종성 분석 및 배출가스 특성에 관한 연구)

  • Seo, Dong Choon;Park, Sung-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.9
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    • pp.29-34
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    • 2019
  • In this study, a gasoline test vehicle was evaluated for drive quality in emissions and fuel economy tests. The measurement results were compared with the manufacturer's suggested values to evaluate whether the tolerance ranges (fuel efficiency -5%, greenhouse gas +5%) were exceeded. We carried out tests with test subjects based on the SAE J2951 evaluation method. The test vehicle was a 2L gasoline vehicle. The drive following performance was found to increase under deliberate driving conditions and decreased in smooth driving conditions. As a result of the analysis of the drive following performance, the closer the value is to 1, the more accurate the driving is. (-) indicates harsh conditions, and (+) indicates gentle conditions. The basic data on the driver following between testers was obtained by analysis of the tests. The fuel efficiency correlation with the drive following performance within the target speed range of the fuel consumption mode. In the future, these measurement results can serve as key data for securing an exhaust gas database and fuel efficiency system for each measurement mode.

Analysis of Flow Velocity Change in Blade Installed Shroud System for Tidal Current Generation (블레이드가 설치된 조류발전용 쉬라우드 시스템 내 유속 변화 분석)

  • Lee, Uk Jae;Han, Seok Jong;Jeong, Shin Taek;Lee, Sang Ho
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.31 no.1
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    • pp.9-16
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    • 2019
  • Flow velocity changes in the shroud system for tidal current power generation due to experimental flow velocities and blade geometry changes were analyzed by hydraulic experiment and numerical simulation. Through the hydraulic experiment, flow velocities at inlet of shroud system and RPM according to blade geometry were measured, and numerical simulation was used to analyze flow velocity changes in shroud. When the experimental flow velocity was increased by about 28% and the shape of the airfoil was applied, the measured flow velocity at the shroud inlet tended to increase by up to about 56%. On the other hand, when airfoil-shaped blades were installed, the flow velocity at the inlet tended to increase by up to 14% compared to conventional blades, and RPM was also the highest at the same conditions. The hydraulic experiment and numerical simulation results showed an error of about 13%, and the trends of the flow velocity changes in each result are similar. Numerical simulation of the flow velocity changes in the shroud showed that the flow velocity tended to increase 1.7 times at the front of the blade compared to the inlet. The results of the flow velocity change analysis in the shroud system obtained from this study will provide the basic data necessary for the development of efficient shroud system for tidal current power generation.

Mechanical and Optical Characteristics of Transparent Stretchable Hybrid Substrate using PDMS and Ecoflex Material (PDMS-Ecoflex 하이브리드 소재를 이용한 투명 신축성 기판의 기계적 및 광학적 특성)

  • Lee, Won Jae;Park, So-Yeon;Nam, Hyun Jin;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
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    • v.25 no.4
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    • pp.129-135
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    • 2018
  • In the stretchable electronic devices, the stretchable substrate is a very essential material which determines the stretchability, performances and durability of the stretchable electronic devices. In particular, the current stretchable materials have hysteresis making difficult to used as sensors and other electronic devices. In this study, we developed a PDMS-Ecoflex hybrid stretchable substrate mixed with PDMS and Ecoflex material in order to increase stretchability and improve hysteresis characteristics. Mechanical behavior of the hybrid substrate was evaluated using a tensile test, and optical transmittance of the hybrid substrate was also measured. As the content of Ecoflex increases, the PDMS-Ecoflex hybrid substrate becomes more flexible, and the elastic modulus decreases. In addition, the PDMS substrate failed a tensile strain of 270%, while the PDMS-Ecoflex hybrid substrate did not fail even at 500% strain indicating excellent stretchability. In the repeated tensile test, the hybrid substrate with 2:1 mixing ratio of PDMS and Ecoflex showed hysteresis. On the other hand, in the case of the hybrid substrate with the mixing ratio of 1:1, hysteresis did not occur at a strain of 50% and 100%. Hence, we developed a stretchable substrate with over 150% stretchability and no hysteresis characteristics. The optical transmittance of the Ecoflex substrate was 68.6%, whereas the transmittances of the hybrid substrate with mixing ratio of 2:1 and 1:1 were 78.6% and 75.4%, respectively. These results indicate that the PDMS-Ecoflex hybrid substrate is a potential candidate for a transparent stretchable substrate.

Sleep Deprivation Attack Detection Based on Clustering in Wireless Sensor Network (무선 센서 네트워크에서 클러스터링 기반 Sleep Deprivation Attack 탐지 모델)

  • Kim, Suk-young;Moon, Jong-sub
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.31 no.1
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    • pp.83-97
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    • 2021
  • Wireless sensors that make up the Wireless Sensor Network generally have extremely limited power and resources. The wireless sensor enters the sleep state at a certain interval to conserve power. The Sleep deflation attack is a deadly attack that consumes power by preventing wireless sensors from entering the sleep state, but there is no clear countermeasure. Thus, in this paper, using clustering-based binary search tree structure, the Sleep deprivation attack detection model is proposed. The model proposed in this paper utilizes one of the characteristics of both attack sensor nodes and normal sensor nodes which were classified using machine learning. The characteristics used for detection were determined using Long Short-Term Memory, Decision Tree, Support Vector Machine, and K-Nearest Neighbor. Thresholds for judging attack sensor nodes were then learned by applying the SVM. The determined features were used in the proposed algorithm to calculate the values for attack detection, and the threshold for determining the calculated values was derived by applying SVM.Through experiments, the detection model proposed showed a detection rate of 94% when 35% of the total sensor nodes were attack sensor nodes and improvement of up to 26% in power retention.