• Title/Summary/Keyword: temperature falling

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A Study of Fundamental Characteristics for $Mg_2SiO_4$ : Tb Phosphor ($Mg_2SiO_4$ : Tb 소자의 기본 특성에 관한 연구)

  • Park, Myeong-Hwan;Park, Chong-Sam;Kwon, Duk-Moon;Lee, Joon-Il
    • Journal of radiological science and technology
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    • v.19 no.2
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    • pp.79-83
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    • 1996
  • The thermoluminescence(TL) response in changing annealing condition, triboluminescence, and darkroom temperature for $Mg_2SiO_4$:Tb phosphor are examined. The experimental results are summerized as follows : 1. The uniformity of TL intensity is better In the disinfected $Mg_2SiO_4$ : Tb than in contaminated one. 2. The triboluminescence of $Mg_2SiO_4$ : Tb is almost not detected even if numbers of $Mg_2SiO_4$ : Tb falling are increased. 3. The fading effect of $Mg_2SiO_4$ : Tb is scarcely affected by freezing room. The followings are resulted from the study. The disinfected $Mg_2SiO_4$ : Tb phosphor should be used in the dose measurement and the immediate reading for $Mg_2SiO_4$ : Tb after exposure is better. And if the reading is not immediately taken, a law darkroom temperature for $Mg_2SiO_4$ : Tb storage is recommended.

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Litter Production and Decomposition in the Pinus rigida Plantation in Mt. Kwan-ak (관악산에 식재된 리기다소나무림에서의 낙엽의 생산과 분해)

  • Kim, Jae-Geun;Chang, Nam-Kee
    • The Korean Journal of Ecology
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    • v.12 no.1
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    • pp.9-20
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    • 1989
  • Annual production and decomposition of litter were studied in piuns rigida platation in Mt. Kwan-ak. The peak time of litter production was October-November. The litterfalll at that time was 54% of annual litter production. But the peak time of litterfall of reproductive parts was Junejuly. The peak times of litter production in Alnus hirsuta plantation were June-July, and November. It is thought that difference of seasonal distribution of letterfall between two forest types were assigned to litter falling factors such as temperature and insects. Total amount of letter loss increased according to time. Particulary, the peak time of loss rate was July-August. It was shown that the protein and phosphorus were accumulated in the letter for an experimental period. The amount of crude protein increased to 150% of initial amount. The amount of potassium was increased by August and then decreased rapidly. The contents of crude fat, holocellulose, lignin, and Na were decreased slowly. The loss of holocellulose was the largiest among them. Calcium was in steady state. It was thought that this variation pattern was assigned to leaching of soluble parts by high temperature, rainfall and growth rate of microorganisms.

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A Study of the Characteristics Times of Polymer Solutions Using the PIV System (PIV 시스템을 이용한 폴리머 용액의 특성시간에 관한 실험적 연구)

  • Lee, Jae-Su;Jeon, Chan-Yeal;Park, Jong-Ho
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1552-1557
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    • 2004
  • Characteristics diffusion time of viscoelastic fluids are determined experimental results of terminal velocity by using the falling ball viscometer. The characteristics diffusion time of viscoelastic fluids are determined with help of the sphere device which is installed to return the dropped sphere from the bottom of the test cylinder without disturbing the working fluids. Terminal velocity of th sphere the reason why experimental of characteristics diffusion time that it is have an effect on the time interval of the measuring. Viscous of the fluid the temperature changed in order to have an effect on temperature and terminal velocity of the ball it becomes larger the possibility of knowing. A result of visualization for flow phenomena of around the sphere uses the PIV and the density of the polymer solution which it appears 2000wppm is to a case which is the right and left becomes symmetry to be it will be able to confirm and according to the time interval, to observed velocity vector of same at first drop the sphere.

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Estimation of Effective Moisture Diffusivity of Rapeseed (Brassica napus L.) (유채 종자의 수본확산계수에 관한 연구)

  • Duc, Le Ahn;Hong, Sang-Jin;Han, Jae-Woong;Keum, Dong-Hyuk
    • Journal of Biosystems Engineering
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    • v.33 no.5
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    • pp.296-302
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    • 2008
  • The effective moisture diffusivity and its dependence on drying temperature during drying of rapeseed were experimentally investigated. The data were recorded from thin layer drying experiments at nine different combinations of drying air temperatures of 40, 50, and $60^{\circ}C$ and the relative humidities of 30, 45, and 60%. The moisture diffusion equation was analyzed using stepwise multiple regression analysis. Effective moisture diffusivities were calculated based on the moisture diffusion equation for a spherical shape using Fick's second law. The effective diffusivities during the drying of rapeseed were $l.72{\times}10^{-11}$, $2.41{\times}10^{-11}$ and $3.31{\times}10^{-11}\;m^2{\cdot}s^{-1}$ at 40, 50 and $60^{\circ}C$, respectively. The activation energy for moisture diffusion during drying was $28.47\;kJ{\cdot}mol^{-1}$. The dependence of moisture diffusivity on temperature was described by an Arrhenius-type equation. Drying occurred in the falling rate period and the internal moisture diffusion phenomenon is the governing physical mechanism of the moisture movement in the particles.

A Study on the Obstacle Avoidance of a Robot Manipulator by Using the Neural Optimization Network (신경최적화 회로를 이용한 로봇의 장애물 회피에 관한 연구)

  • 조용재;정낙영;한창수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.2
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    • pp.267-276
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    • 1993
  • This paper discusses the neural network application in the study on the obstacle avoidance of robot manipulator during the trajectory planning. The collision problem of two robot manipulators which are simultaneously moving in the same workspace is investigated. Instead of the traditional modeling method, this paper processing based on the calculation of joint angle in the cartesian coordinate with constrained condition shows the possibility of real time control. The problem of the falling into the local minima is cleared by the adaptive weight factor control using the temperature adding method. Computer simulations are shown for the verification.

A Study on Air-Conditioning System for Excavator using Forced Exhaust (강제배기를 이용한 굴삭기 공기조화 시스템에 관한 연구)

  • Hwang, J.H.;Jeong, C.S.;Ko, J.H.;Yang, S.Y.
    • Journal of Drive and Control
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    • v.10 no.2
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    • pp.23-29
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    • 2013
  • The excavator is used in a variety of construction environments. There are many kinds of risk like falling rocks or harmful dust. The excavator cabin protects the operator not only from these harmful environments but also provides a comfortable working environment. By the way, the excavator cabin consumes a lot of energy for cabin air conditioner. For this reason, the research is required to reduce energy consumption. This study suggests the air conditioning system for excavator using forced exhaust. First, the forced exhaust system simulated by AMESim tool and surveyed the applicability. Using AMESim simulation, it was investigated the effect of cabin inside temperature by intake flow rate and intake air temperature. The experiment executed using the 1.5 ton excavator and field tested according to the intake flow rate. Finally, verified the applicability on the air conditioning system for excavator using forced exhaust.

An Experimental Study on the Cooling Tower of Plume Prevention and Performance Improvements (냉각탑 백연방지의 성능 향상에 관한 실험적 연구)

  • JEONG, SOON YOUNG;LEE, BYEONG CHEON;KIM, SUNG
    • Journal of Hydrogen and New Energy
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    • v.30 no.6
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    • pp.578-584
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    • 2019
  • The occurrence of white plume in the cooling tower is phenomenon that the steam in the air through the cooling tower fan is condensed again by the cold ambient air to become saturated moist air. Accordingly, this can cause many problems like spoiling landscape around the cooling tower, odor of ambient air, falling accident by frozenness in the winter, and traffic accident, etc. This study was to install the heat exchanger in the inside of the cooling tower in order to prevent the white plume phenomenon in the cooling tower without affecting the performance of cooling tower. In addition, this study was to discharge the part of cooling water into the atmosphere through the recirculation of heat exchanger after creating dry air by heating the saturated moist air to the dew point temperature. At that time, this study was to conduct the experimental study in order to secure the optimal design data to prevent the white plume in the cooling tower because it checked the dry·moist temperature and relative humidity in the inside·outside of cooling tower on the moist air, and evaluated the performance of the heat exchanger.

Changes of Physical and Sensory Quality in Home-delivered meals for elderly as affected by Packaging methods and Storage conditions 3 (노인을 위한 가정배달급식의 포장방법 및 저장조건에 따른 물성ㆍ관능적 품질 변화 3)

  • 김혜영;류시현
    • Korean journal of food and cookery science
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    • v.19 no.3
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    • pp.374-389
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    • 2003
  • The Purpose of this study was to propose the most effective packaging method and storage conditions to apply to home-delivered meals for the elderly Changes in the physical and sensory qualities of pan fried oak mushroom and meat, soy sauce glazed hair tail and roasted dodok, in wrap packaging, top sealing and vacuum packaging were evaluated during storage at 25, 4 and -18$^{\circ}C$, for 5 days. The speed of falling-off in the foods qualities, under chilled and frozen storage conditions did not differ much as the 5 day storage period was too short for a proper assessment. The sensory characteristics of taste and texture were better evaluated in the chilled than in the frozen storage. The most effective packaging method at all the storage temperatures was the vacuum packaging, which assured the safety of the foods by the removal of oxygen. The lightness, springiness and hardness were significantly influenced by the storage temperature, period and packaging method, while the sensory characters were affected by storage temperature and the period. In conclusion, the quality of the vacuum packed pan fried oak mushroom and meat and soy sauce glazed hair tail, in frozen storage, were still fresh after the five days of the experiment. The shelf-life of those foods with wrap packaging, in chilled storage, were suggested to be three days. The quality of the roasted dodok, with vacuum packaging in chilled storage, was preserved for five days.

Design and Implementation of Prototype Model for Infant Care system using Smart Phone (스마트폰을 이용한 Infant Care 시스템의 프로트 타입모델 설계 및 구현)

  • Choi, Sung-Jai
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.22 no.4
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    • pp.103-109
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    • 2022
  • This significance of the infant care system has emerged due to sudden infant death during sleeping. This paper presented a design and implementation of a prototype model, which is a infant care device controlled by a smartphone using Bluetooth technology. Prototype Device Model consists of MCU(microcontroller unit), Accelerometer Sensor, Temperature Measuring Sensor, Sound Measuring Sensor, Bluetooth Module, and Camera Module. The proposed application transfers the information to the parent's smartphone and computers, such as infant's falling, crying, and fever detection. A test verified the availability of a prototype infant care system model using Bluetooth Low Energy with operating the low power driving.

Study on Rheological Properties of Wheat Flour Mixed with Buckwheat Powder (메밀가루를 첨가한 냉동쿠키의 유변학적 특성)

  • Lee, Hyun-Ja;Kim, Min-A;Lee, Hyun-Joo
    • Journal of the East Asian Society of Dietary Life
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    • v.21 no.1
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    • pp.53-59
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    • 2011
  • The purpose of this study was to investigate the properties of frozen cookies containing buckwheat flour. Buckwheat flour was added to cake flour bases at concentrations of 3%, 6%, and 9%. Falling numbers, RVA (rapid visco analyzer) increased with the addition of buckwheat flour, whereas initial pasting temperature decreased. The set back value, which is a prediction of retrogradation, did not show any significant difference. The alveographic P values of the treatment were lower than that of the Control. In the farinogram test, water absorption increased upon the addition of buckwheat flour, whereas stability and farinogram quality number decreased. In conclusion, the addition of 6% buckwheat flour is recommended to obtain the optimal volume of frozen cookies.