• Title/Summary/Keyword: Heating speed

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Effects of Extrusion Process Parameters on Puffing of Extruded Pellets (압출성형 공정변수가 압출성형 펠릿의 팽화에 미치는 영향)

  • Kim, Jae-Hyun;Ryu, Gi-Hyung
    • Korean Journal of Food Science and Technology
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    • v.33 no.1
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    • pp.55-59
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    • 2001
  • Pressure-puffing system or extruder has been used to puff rice kernel or rice flour. Most of the study on rice puffing were the effect of process conditions such as moisture content and heating temperature on physical and chemical characteristics of popped rice. The study on mechanism and development of instant puffed rice like popcorn has been limited. Extruded waxy rice pellets were puffed in a microwave oven after drying and conditioning. Extruded pellets were formed with extrusion conditions of $20{\sim}27%$ moisture content, 2.76 MPa $CO_2$ gas injection pressure and 200 rpm screw speed. Under these conditions, puffed waxy rice pellets in microwave oven had low density and soft texture. Density and texture of puffed waxy rice pellet could be optimized by control of moisture content, $CO_2$ gas injection pressure and screw speed that affect significantly when puffing extruded waxy rice pellet.

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Analysis on Thermal Structural Characteristics of Thermal Protection System Panel for a High-speed Vehicle (초고속 비행체 열방어 시스템 패널의 열구조 특성 분석)

  • Lee, Heesoo;Kim, Yongha;Park, Jungsun;Goo, Namseo;Kim, Jaeyoung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.942-944
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    • 2017
  • High-speed vehicles are subjected to complex loads, such as acoustic pressure from the engine at launch and aerodynamic heating and aerodynamic pressure during flight. A thermal protection system panel is required to protect internal systems such as the fuel tank of the vehicle from the external environment. This study defines analytical models for heat transfer and thermal structure characteristics of the thermal protection system panel. Furthermore, the study performed parameters analysis to achieve the thermal structural integrity and to make it lighter.

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Study Case on the Bag Cultivation of Pleurotus ostreatus Using Fermenter (발효기를 이용한 느타리버섯 봉지재배 경영사례)

  • Chang, Hyun-You;Suh, Gyu-Sun;Lee, Soo-In
    • Journal of Practical Agriculture & Fisheries Research
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    • v.10 no.1
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    • pp.169-181
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    • 2008
  • The purpose of this study was to produce Pleurotus ostreatus using fermenter with bag cultivation. These results are as follows. 1. While mushroom composts were being fermented in a fermenter, the physical property of the fermented composts was getting better when there isn't any screw or revolving flies in the fermenter and the strength of pressing the composts was getting less. 2. The composts were fermented well as slaked lime of 1% density added to the composts. 3. According to the result of examining our fermenting ways, composts were in the best condition after being fermented for 48 hours since the temperature in a fermenter has come to 60℃, which could be reached by heating the fermenter by 40℃ after putting compost materials and water into it. 4. The good condition of fermenting could be maintained by controlling the speed of revolving flies, therefore the speed be down when the temperature is above 60℃ and up bellow 60℃. 5. Since the composts had been added with 1.5~2% of cottonseed meal or rice bran, the fermented composts were in good condition and also the quantity and quality of the mushroom produced on the fermented composts were satisfied. 6. There were needed 7 hours of labour for 3days from the first day of putting composts into a fermenter for fermenting 3.5M/T(10,000~12,000bags of 750~800g per bag) of composts to the third day of finishing the fermenting work, and also the cost was 112,066₩(130$) including 52,066₩(60$) of electric charge and fuel expense.

Study on Shift characteristic of Small reducer using Eccentric arm (편심캠을 이용한 소형감속기의 변속특성에 관한 연구)

  • Youm, Kwang-Wook;Ham, Seong-Hun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.609-614
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    • 2017
  • In this study, a new type of eccentric cam was used for the development of a small size reducer with a two-shift reduction ratio while maintaining the same volume as the existing one-shift speed reducer. Therefore, a two-shift speed reducer was designed using the concept of a continuously variable transmission applied to automobiles. The cam was designed to have an eccentric shape with a $180^{\circ}$ phase difference to act as a tensioner to minimize slip by squeezing the V-belt connected to the deceleration pulley and the acceleration pulley, respectively. The cam was designed to have a diameter of 35mm and an outer diameter of 18mm so that the outer portion of the v-belt could contact the cam perfectly. A pulley with a diameter of 50.8mm was installed on the low speed pulley input shaft for deceleration and a pulley with a diameter of 76.2mm was provided on the output shaft. In the high-speed pulley for acceleration, a pulley with a diameter of 76.2mm is provided on the input shaft, and a pulley with a diameter of 50.8mm is provided on the output shaft. Based on the design details, the power transmission efficiency test and the heating characteristics of the transmission were tested to verify the feasibility. In addition, through validation, the suitability of the reducer was demonstrated.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

Physicochemical Properties of High Yielding Non-waxy Rice Flours Extruded with Different Moisture Contents (다른 수분함량으로 압출성형한 다수확 멥쌀가루의 이화학적 특성)

  • Jeong, So-Hee;Kang, Wie-Soo;Shin, Mal-Shick
    • Korean journal of food and cookery science
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    • v.27 no.6
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    • pp.745-754
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    • 2011
  • To improve the textural properties of gluten free rice flour based products, the physicochemical and pasting properties of extruded non-waxy rice flours using extruder were investigated. The high yielding Tongil type rice variety, Hanarum was used. Hanarum rice flour was prepared by dry milling from soaked and dried rice grain. The operation conditions of twin screw extruder were 250 rpm of screw speed, $160^{\circ}C$ of barrel temperature, and 24, 27, and 30% of moisture content. Hanarum extruded rice flour (HERF) were lower in crude lipid and ash contents, but higher in crude protein than Hanarum rice flour (HRF). The color values of HERF showed significantly different (p<0.05) with different moisture contents. Water binding capacities, apparent amylose contents, and damaged starch of HERF were higher than those of HRF. Moisture contents affected water binding capacities of HERF. Solubility increased with increasing heating temperature and solubilities of HERF differed significantly (p<0.05). X-ray crystallinity was changed after extrusion cooking and that of HERF showed sharp peaks at $2{\theta}=18-20^{\circ}$. The pasting viscosities of HERF kept lower values (~ 10 RVU) constantly.

A Study On the Friction Torque and Temperature Distribution of Magnetic Fluid Seals (자성유체시일의 마찰토크와 온도분포 해석에 관한 연구)

  • Kim, Chung-Kyun;Kim, Han-Goo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.1
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    • pp.53-61
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    • 1997
  • The performance characteristics of magnetic fluid seals are studied numerically as a function of working gap, pole width, angle of pole sharpening, and shaft speed. The temperature distribution of a magnetic fluid seal with multiple tooth is investigated as a function of the contact fraction of magnetic fluids at the periphery of pole tooth using a finite element method. The most significant design parameter of a magnetic fluid seal is the working gap between the pole pieces and the rotating shaft. The result shows that with increasing the working gap, the friction torque decreases radically. The practical working gap for the pole pieces with triangular tooth zone profile is 0.2-0.4mm. The FEM results indicate that the optimal filling of a magnetic fluid between the pole pieces and the shaft is very important due to the accumulations of nonuniform friction heating within the pole pieces, which may interfere the magnetic circuit flow.

Quality Assessment of Performance in the University Foodservice by Students Living in Incheon (인천지역 대학생에 의한 대학급식소의 급식서비스에 대한 품질 평가)

  • 노정옥;우경자;한복진
    • Journal of the East Asian Society of Dietary Life
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    • v.14 no.3
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    • pp.294-301
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    • 2004
  • This study was conducted to investigate the quality assessment of performance of the university foodservice. Self administered questionnaires were collected from 305 students living in Incheon. Statistical data analysis was completed using a SPSS v. 10.0 program. The results were summarized as follows: 61.4% of male students and 48.1% of female students responded to have lunch regularly. Only 23.4% of male students and 14.1% of female students used the university foodservice daily. Reasons for the irregularity of lunch were responded as “lecture”, “eating when I want” and “appointment with friends”, etc. The quantity, temperature, nutritional value, appearance, hygiene, taste and freshness of foods and price of menus were evaluated as appropriate but using seasonal foods, number of side-dishes, etc. as unsatisfactory. Service speed, cloth hygiene, neatness and kindness of employee were evaluated as appropriate. For the facilities of foodservice, counter location, menu board and lighting facilities were evaluated as appropriate but heating facilities, disposition of tables and chairs of dining hall were as unsatisfactory. Sanitation of floors and walls of dining hall, restroom and utensils, etc. was evaluated as low.

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A Numerical Study on the Characteristics of Flow Field, Temperature and Concentration Distribution According to Changing the Shape of Separation Plate of Kitchen Hood System (주방용 후드시스템의 분리판 형상 변화에 따른 유동장, 온도 및 농도특성에 관한 수치적 연구)

  • Lee, Kwang-Sub;Lee, Chang-Hee;Lim, Kyoung-Bin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.2 s.245
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    • pp.177-185
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    • 2006
  • This study aims deriving analysis the flow characteristic of kitchen hood system with using 3-D numerical analysis method and improving the system to expel pollutes more efficiently. To understand the flow characteristics of four models, this study only focuses on velocity field, temperature field, and concentration field varying with followings whether separation plate is set or not and the shapes of separation plates. The quantity of air, speed of exhaust fan and temperature and concentration of heating source are concerned as constant values. The three models having different shapes have one exhaust port and the model which has the vent at the closest position to where pollutes are generated is discovered to be the most efficient model. Compare to the initial model (having no separation plate), it was $1.4-1.9\%$ more efficient at temperature distribution and $9.4-11.9\%$ more at $CO_2$ concentration distribution.

Design of a Neuro Observer for Reduction of Estimate Error (추정오차 저감을 위한 뉴로 관측기 설계)

  • Yoon, Kwang-Ho;Kim, Sang-Hoon;Ban, Gi-Jong;Choi, Sung-Dae;Park, Jin-Su;Kim, Lark-Kyo;Nam, Moon-Hyon
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.693-695
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    • 2004
  • Among modem control method, the observer is being used widely because it has the advantage of the guarantee of reliability on financial problem, over heating, and physical shock. However, an existing state observer and a sliding observer have such problems that an experimenter needs to know dynamics and parameters of the system. And also, the high gain observer has such a problem that it has transient state at the beginning of the observation. In this paper, the neuro observer is proposed to improve these problems. The proposed observer complement a problem that occur from increase of gain of High-gain observer in proportion to the square number of observable state variables. And also, the proposed observer can tune the gain obtained by differentiating observational error at transient state automatically by using the backpropagation training method to stabilize the observational speed. To prove a performance of the proposed observer, it is simulated that the comparison between the state estimate performance of the proposed observer and that of sliding, high gain observer is made by using a sinusoidal input to the observer which consists of four layers in stable 2nd order system.

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