• 제목/요약/키워드: Temperature dependent development

검색결과 312건 처리시간 0.023초

Free vibration investigation of functionally graded plates with temperature-dependent properties resting on a viscoelastic foundation

  • Abdeldjebbar Tounsi;Adda Hadj Mostefa;Amina Attia;Abdelmoumen Anis Bousahla;Fouad Bourada;Abdelouahed Tounsi;Mohammed A. Al-Osta
    • Structural Engineering and Mechanics
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    • 제86권1호
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    • pp.1-16
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    • 2023
  • The free vibration of temperature-dependent functionally graded plates (FGPs) resting on a viscoelastic foundation is investigated in this paper using a newly developed simple first-order shear deformation theory (FSDT). Unlike other first order shear deformation (FSDT) theories, the proposed model contains only four variables' unknowns in which the transverse shear stress and strain follow a parabolic distribution along the plates' thickness, and they vanish at the top and bottom surfaces of the plate by considering a new shape function. For this reason, the present theory requires no shear correction factor. Linear steady-state thermal loads and power-law material properties are supposed to be graded across the plate's thickness. Uniform, linear, non-linear, and sinusoidal thermal rises are applied at the two surfaces for simply supported FGP. Hamilton's principle and Navier's approach are utilized to develop motion equations and analytical solutions. The developed theory shows progress in predicting the frequencies of temperature-dependent FGP. Numerical research is conducted to explain the effect of the power law index, temperature fields, and damping coefficient on the dynamic behavior of temperature-dependent FGPs. It can be concluded that the equation and transformation of the proposed model are as simple as the FSDT.

먹노린재(Scotinophara lurida)의 발생생태와 온도의존 발육모형 (Developmental Ecology and Temperature-dependent Development Model of Scotinophara lurida (Heteroptera: Pentatomidae))

  • 최덕수;김효정;오상아;이진희;조아해;마경철
    • 한국유기농업학회지
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    • 제28권2호
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    • pp.251-261
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    • 2020
  • 친환경 벼 재배지역 위주로 피해가 점차 확대되는 먹노린재(Scotinophara lurida) 방제기술 개발을 위하여 발생생태 및 온도의존 발육모형을 산출하였다. 2019년도 먹노린재 월동 후 생존율 조사결과 총 224마리 중 167마리가 생존하여 생존율은 72.8%였다. 먹노린재 월동성충은 논에 6월 중하순부터 발생하고, 7월 상순에 산란하고, 8월 중하순에 1세대 성충이 발생한다. 온도의존 발육모형을 구하기 위하여 18, 21, 24, 27, 30℃ 14L:10D 조건의 항온기에서 온도별, 발육단계별 발육기간을 조사하였다. 18, 21, 24, 27, 30℃의 온도조건에서 알에서 성충이 될 때까지의 기간은 각각 119.8, 73.1, 53.5, 39.4, 82.0일로 27℃에서 가장 발육이 잘 되었다. Excell 프로그램을 이용하여 온도와 발육속도와의 관계를 2차 다항식으로 분석하여 회귀곡선을 얻었고 이를 근거로 발육단계별 발육영점온도와 유효적산온도를 산출하였다. 알에서 5령 약충까지 먹노린재 발육영점온도는 17.9℃, 유효적산온도는 380.2DD였다.

Temperature-dependent Index of Mitotic Interval (τ0) for Chromosome Manipulation in Korean Rose Bitterling Rhodeus uyekii

  • Kim, Bong-Seok;Lim, Sang-Gu;Gil, Hyun-Woo;Park, In-Seok
    • Fisheries and Aquatic Sciences
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    • 제14권4호
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    • pp.429-433
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    • 2011
  • Eggs of Korean rose bitterling Rhodeus uyekii were collected and fertilized to observe temperature-related cleavage rates and mitotic intervals (${\tau}_0$). As the water temperature was increased, the slope of first cleavage frequency with elapsed time after fertilization increased, and approximately 30% of fertilized eggs reached first cleavage frequency at every 15 min. At higher temperatures, eggs developed faster and underwent further identical developmental processes. There were strong, negative correlations between ${\tau}_0$ and water temperatures at all temperatures studied (Y = -1.225X + 70.05, $r^2=0.988$, where Y is ${\tau}_0$ and X is temperature).

콩줄기명나방(Ostrinia scapulalis) (나비목: 포충나방과)의 발육과 산란에 미치는 온도의 영향 (Effects of Temperature on the Development and Reproduction of Ostrinia scapulalis (Lepidoptera: Crambidae))

  • 안정준;김은영;서보윤;정진교
    • 한국응용곤충학회지
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    • 제61권4호
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    • pp.577-590
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    • 2022
  • 콩줄기명나방은 콩과작물 특히 팥을 가해하는 해충으로 알려져 있다. 본 연구는 온도가 콩줄기명나방의 발육단계별 발육기간, 성충의 수명과 산란특성에 미치는 영향을 파악하고자 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 36℃ 항온조건에서 조사하였다. 알과 유충은 7, 10, 13℃를 제외한 항온조건에서 다음 생애단계로 성공적으로 발육하였다. 알, 유충, 번데기의 발육기간은 온도가 상승할수록 짧아지는 경향을 보였다. 콩줄기명나방 발육단계별 발육 최저, 최고 한계는 LRF와 SSI모델을 이용하여 계산하였고 발육영점온도와 유효적산온일도는 선형회귀분석을 이용하였다. 1령 유충 부화부터 성충출현까지의 발육영점온도와 유효적산온일도는 13.5℃와 384.5DD로 추정되었다. SSI모델을 이용한 부화부터 성충출현까지 발육 최저 및 최고온도는 19.4℃과 39.8℃였고 이들간의 차이 즉 발육적정온도범위는 20.4℃였다. 성충은 16℃와 34℃ 범위에서 부화하는 알을 생산하였고, 25℃에서 최대 약 416마리의 자손을 낳았다. 노화율, 나이별 생존율, 나이별 누적산란율, 온도의존 산란수에 관련된 성충모델들이 작성되었다. 본 연구에서 제시한 온도발육모형과 산란모형은 야외에서 콩줄기명나방의 개체군동태를 이해하고 콩과작물의 종합적인 해충군관리체계를 마련하는데 기초기반자료로 활용될 것으로 기대된다.

잔물땡땡이의 온도발육모형과 생물계절 (Temperature-dependent development models and phenology of Hydrochara affinis)

  • 윤성수;김명현;어진우;송영주
    • 환경생물
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    • 제38권2호
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    • pp.222-230
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    • 2020
  • 논 생태계 서식 생물을 장기적으로 모니터링하여 기후변화의 영향을 평가하기 위한 기초 연구로 잔물땡땡이의 발육단계별 온도발육모형을 선정하고 생태적 매개변수(유효적산온도, 발육한계온도, 발육최적온도, 발육최고온도)를 추정하였다. 선정된 온도발육모형을 이용하여 위도별 4 지역(철원, 당진, 부안, 해남)에서 발생하는 잔물땡땡이의 세대 수를 각 지역의 일 평균기온을 사용하여 예측하였다. 실험온도 구간(18~30℃)에서는 모든 성장단계에서, 발육속도가 온도에 따라 선형적으로 증가하였고 모형 사이의 적합성은 유의한 차이가 없었다. 하지만 발육최적온도와 달리 발육한계온도는 모형별로 상당한 차이를 보였다. 잔물땡땡이는 고위도인 철원에서 3.6 세대가 발생하지만 다른 지역에서는 4.3 세대가 발생하는 것으로 예측되었다. 본 연구의 결과는 기후변화에 따른 생물계절 변동 및 논 생태계 생물다양성 보전 연구의 기초자료로 활용될 것으로 보인다.

DEVELOPMENT OF GREEN'S FUNCTION APPROACH CONSIDERING TEMPERATURE-DEPENDENT MATERIAL PROPERTIES AND ITS APPLICATION

  • Ko, Han-Ok;Jhung, Myung Jo;Choi, Jae-Boong
    • Nuclear Engineering and Technology
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    • 제46권1호
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    • pp.101-108
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    • 2014
  • About 40% of reactors in the world are being operated beyond design life or are approaching the end of their life cycle. During long-term operation, various degradation mechanisms occur. Fatigue caused by alternating operational stresses in terms of temperature or pressure change is an important damage mechanism in continued operation of nuclear power plants. To monitor the fatigue damage of components, Fatigue Monitoring System (FMS) has been installed. Most FMSs have used Green's Function Approach (GFA) to calculate the thermal stresses rapidly. However, if temperature-dependent material properties are used in a detailed FEM, there is a maximum peak stress discrepancy between a conventional GFA and a detailed FEM because constant material properties are used in a conventional method. Therefore, if a conventional method is used in the fatigue evaluation, thermal stresses for various operating cycles may be calculated incorrectly and it may lead to an unreliable estimation. So, in this paper, the modified GFA which can consider temperature-dependent material properties is proposed by using an artificial neural network and weight factor. To verify the proposed method, thermal stresses by the new method are compared with those by FEM. Finally, pros and cons of the new method as well as technical findings from the assessment are discussed.

온도 변화율을 이용한 자이로 바이어스 히스테리시스 오차 보상 기법 (Compensation Method of Gyro Bias Hysteresis Error using the Rate of Temperature)

  • 유해성;김천중;성창기;이인섭;박상은;박흥원
    • 한국군사과학기술학회지
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    • 제18권2호
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    • pp.109-114
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    • 2015
  • A method to compensate a bias hysteresis error of the ring laser gyro using the rate of temperature is proposed in this paper. Until now, we generally have measured and compensated the error of gyro and accelerometer using the temperature. However, we utilize the measured values of the temperature dependent error elements on the temperature rate in navigation system level. We show through experiments that the proposed method can improve the navigation performance and be very effective.

성숙도가 폴리에스터 폴리머 콘크리트의 강도발현에 미치는 영향 (Effect of Maturity on Strength Development of Polyester Polymer Concrete)

  • 연규석;김광우;김관호;이윤수
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1994년도 가을 학술발표회 논문집
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    • pp.223-228
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    • 1994
  • The strength development of polymer concrete using an unsaturated polyester polymer varies depending on many factors. However, the strength development is mostly dependent upon the age and curing temperature if the mixture ratios are the same. This study conducted to experimentally describe the relationship between the strength development and maturity which is defined as a function of $\Sigma$(time $\times$ temperature). The research result may be applied to predict the compressive, tensile and splitting strengths of the polymer concrete by computing the maturinty of the concrete.

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Effect of temperature on the development of the Common Grass Yellow, Eurema hecabe

  • Kim, Seonghyun;Park, Haechul;Park, Ingyun
    • International Journal of Industrial Entomology and Biomaterials
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    • 제31권2호
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    • pp.35-39
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    • 2015
  • The developmental responses of insects to temperature are important considerations in gaining a better understanding of their ecology and life histories. Temperature-dependent phenology models permit examination of the effects of temperature on the geographical distributions, population dynamics, and management of insects. Measurements of insect developmental and survival responses to temperature pose practical challenges that depend on the chosen modality, variability among individuals, and high mortality rates near the lower and upper threshold temperatures. Different temperature levels can significantly affect larval development of Eurema hecabe. The development of E. hecabe reared on leaves of Lespedeza cuneata was investigated at three temperature regimes (20, 25, and 30℃), a relative humidity of 60%, and a light:dark photoperiod of 14:10 h. The developmental time from larva to adult was 34.3, 20.6, and 17.9 d at temperatures of 20, 25, and 30℃, respectively. Pupal rate was 47.6%, 47.6%, and 61.9% at temperatures of 20, 25, and 30℃, respectively. The developmental threshold temperature estimated from larva to pupae was 8.1℃ with 381.7 degree-days. There is an increasing need for a standardized manual for rearing this butterfly species based on adequate knowledge of its ecology.

NUMERICAL INVESTIGATION OF THE SPREADING AND HEAT TRANSFER CHARACTERISTICS OF EX-VESSEL CORE MELT

  • Ye, In-Soo;Kim, Jeongeun Alice;Ryu, Changkook;Ha, Kwang Soon;Kim, Hwan Yeol;Song, Jinho
    • Nuclear Engineering and Technology
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    • 제45권1호
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    • pp.21-28
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    • 2013
  • The flow and heat transfer characteristics of the ex-vessel core melt (corium) were investigated using a commercial CFD code along with the experimental data on the spreading of corium available in the literature (VULCANO VE-U7 test). In the numerical simulation of the unsteady two-phase flow, the volume-of-fluid model was applied for the spreading and interfacial surface formation of corium with the surrounding air. The effects of the key parameters were evaluated for the corium spreading, including the radiation, decay heat, temperature-dependent viscosity and initial temperature of corium. The results showed a reasonable trend of corium progression influenced by the changes in the radiation, decay heat, temperature-dependent viscosity and initial temperature of corium. The modeling of the viscosity appropriate for corium and the radiative heat transfer was critical, since the front progression and temperature profiles were strongly dependent on the models. Further development is required for the code to consider the formation of crust on the surfaces of corium and the interaction with the substrate.