Characteristics Of Temperature Change Research Articles

Environment Analysis with Temperature Change in Jarud in Recent 59 Years

By means of the linear trend analysis and accumulated variance analysis, the climate change characteristics of temperature from 1953 to 2011 in Jarud Banner were analyzed. The results showed that temperature of annual and seasonal in Jarud has risen in recent 59 years; especially in spring. The decadal variation of annual mean temperature went down greatly since1950s, and began to increase since in the late 1980s, while it showed most obvious trend since 21stcentury. The cold phase was from 1953 to 1986 and warm phase from 1987 to 2011.

Adaptation of the modified pulse method for determination of thermal diffusivity of solids in the vicinity of the second-order phase transition points

Abstract The paper presents the adaptation of the modified pulse method for investigating temperature characteristics of thermal diffusivity in the vicinity of the second-order phase transition points. The principle of the adaptation consists in the modified in relation to the original method, development of the characteristics of temperature changes between boundary surfaces of a flat-parallel specimen after the laser shot onto its front surface. The application of this adaptation was illustrated with investigation into thermal diffusivity of nickel (99.9% wt) in the temperature range of 20-380◦C. In all cases the measurement error was less than 3%, and the averaging interval for the measured values of thermal diffusivity was not greater than 1.2 K.

자동차 워셔액 가열시스템의 온도 변화 특성에 관한 연구

본 논문은 추운 겨울 자동차 앞면 유리에 생기는 성에를 제거하는 워셔액 가열시스템의 가열과 분사에 따른 온도변화 특성에 관한 연구이다. 지금까지 다른 연구에서는 워셔액 가열시스템에 대한 온도 변화 특성을 간단한 수학적 모델링을 통하여 분석하였으나 본 연구에서는 워셔액 가열시스템의 보다 더 최적화된 제어시스템 설계를 위해 워셔액 가열시스템의 시간에 따른 열유동 특성 변화를 전산유체해석(CFD)을 통해 파악하기로 한다. 이를 위해서 워셔액 가열시스템의 주요 부분인 히터와 워셔액에 대한 비정상상태 해석을 수행하고 워셔액 전체의 온도 변화 특성을 분석하였다. 이를 토대로 워셔액의 가열시간과 분사시 온도 특성을 파악하여 워셔액 가열시스템의 최적설계의 기본자료로 활용하도록 하였다. The present paper has been accomplished to elucidate the characteristics of temperature change in a car washer heater system for removal of frost formed at the surface of a car. The previous studies had used a simplified mathematical modeling to analyse the temperature change characteristics for a car washer heater system. In the present study, an unsteady computational fluid flow and heat transfer analysis for a washer heater system has been done by using computational fluid dynamic analysis method. From the present CFD analysis, the time dependent temperature change in a car washer heater system has been analysed and derived the heating time and ejection temperature of the washer liquid to establish the optimal design basis for a washer heater system.

The Effect of Temperature Condition on Material Deformation and Die Wear

The characteristics of temperature change on die and billet are very complex during the deformation process because of the interaction between them and some unstable external factors. In this paper, the numerical simulation model for the crank shaft die forging was established by means of the rigid-plastic FEM method. The model was validated by optical non-contact 3D measurement—ATOS. Based on available research results, this paper explored the effect of temperature conditions on material deformation and die wear. Three parameters, press velocity and initial temperature of billet and die, were chosen to illustrate the effects. From the experimental results, the effect of process parameters on deformation ability of the material is simple, while the effect on die wear is relatively complicated. The press velocity plays an important role on die wear when the initial temperature of the billet has larger influence on material deformation. A conclusion can be drawn that when the initial temperature of the billet is 1100 °C, the initial temperature of the die is 250 °C, and the velocity is kept in the range of 200-300 mm/s, the optimum solution for deformation ability of the material and die wear can be obtained. It is possible for the conclusion to be extended further for the control of temperature condition to optimize die life and material deformation.

三峡库区近百年来气温变化特征The Variation Characteristics of Temperature in the Three Georges Reservoir Area During the Past Nearly 100 Years

利用1924—2011年重庆和宜昌站气温资料，分析了三峡库区近百年来气温变化特征，结果表明：从线性趋势、年代变化、突变和周期分析表明近88年重庆和宜昌气温的变化特征是比较一致的，两段显著偏暖的时期分别是20世纪20年代中期至40年代和20世纪90年代中期至今。用重庆和宜昌站的平均来代表三峡库区，库区气温阶段变化与重庆、宜昌站基本一致，20世纪90年代中后期至今出现的显著增温现象迟于我国1986年前后开始的普遍增温。库区各季节气温变化存在差异，四个季节最近一次增暖主要集中在20世纪90年代中期或中后期。近88年来三峡库区年平均气温发生两次突变，1947年左右突变为降温趋势；1996年左右突变为增暖趋势。三峡库区年平均气温2～4 a周期变化最为显著，4 a左右的周期1980年代后期开始显著。1920年代到1980年代存在的16～20 a的年代际周期，但能量较年际周期弱。近88年三峡库区与全球气温变化存在较大差异，最近一次显著增暖时间比较，三峡库区比全球滞后约10年。 By using the Three Gorges reservoir area’s temperature data of the Chongqing and Yichang station(from 1924 to 2011), the variation characteristics of temperature in the Three Georges Reservoir Area during the past 88 years are analyzed .The results demonstrate : the linear trend, decadal variation, sudden change and the cycle analysis shows that the temperature changing characteristics of Chongqing station and Yichang is highly the same in the last 88 years, the two significantly warmer periods are the mid-1920s to the 1940s and the mid-1990s to the present. The Three Gorges reservoir area can be represented by the average values of Chongqing and Yichang, the temperature change in phases of the reservoir area is basically the same with Chongqing, Yichang. The significant warming phenomenon appeared since the late 1990s is later than the China average warming stared at the year around 1986. The seasonal temperature changes have some differences, the latest warming of the four seasons mainly concentrated in periods of the mid-1990s and later 1990s. There are two sudden changes of the Three Gorges reservoir area’s temperature during the recent 88 years: one is a cooling trend around the year 1947, one is a warming trend around 1996. The 2 – 4 a cycle changes of the Three Gorges reservoir area’s average temperature is the most significant, the 4a cycle changes are becoming very significant since the later 1980s.There is a 16 – 20 a decadal period between the 1920s and the 1980s, but its energy is weaker than the annual period. The Three Gorges reservoir area’s temperature changes are different with the global temperature changes greatly during the past 88 years, comparing the latest significant warming time, the former is about 10 years behind the later.

터널 화재 시 열감지기 작동 온도의 비교에 관한 실험적 연구

건설 기술 발전과 국토의 효율적인 활용으로 인하여 건설되고 있는 터널은 지하 공간과 같은 폐쇄 공간의 특성으로 화재 시발생하는 연기와 열은 인명 및 물적 피해에 영향을 주는 매우 큰 위험요소이다. 본 연구에서는 광케이블을 이용하여 온도 변화를 측정하는 화재 감지 시스템을 설치하여 감지기가 동작한 온도 변화 값 및 시간과 실 화재 실험과 동일한 조건으로 화재 시뮬레이션을 수행하여 온도센서의 온도 변화 값 및 시간을 비교, 분석하였다. 실험 결과 화재실험과 화재 시뮬레이션의 온도변화는 점화 후 1분 이내에 화재를 감지하여 신호를 경보하는 것으로 나타났으며, 화재 감지기와 시뮬레이션 온도 센서의 온도변화 특성은 터널 내부의 기류 속도와 밀접한 관계를 가지는 것으로 나타났다. 또한 터널 화재는 연기의 방향에 의해 피난과 소방대 진입에 영향을 미치므로 화재 지점과 화재 방향을 파악할 수 있어야 한다. Due to the rapid development of construction technology with effective land utilization in this nation, many tunnels were and are being built across the country. However, the smoke and the heat generated from tunnel fire are the most important critical factors which may results in both massive personal injury and property damage, especially, due to the closed surrounding of the tunnel. Considering this particular nature of the tunnels, this study aims to install a fire detection system using an optic fiber cable to measure the temperature changes, compare, and analyze the resulted values with the times of temperature changes of the sensor by performing fire simulations under the same condition as a real fire test. From the results, it has been found that the temperature sensor detects a fire occurrence and generates an alarm within one minute after ignition for both a real fire test and a fire simulation alike, and also that the characteristics of temperature changes of the sensor has close relations with the speeds of the currents inside the tunnel. In addition, considering the tunnel fires can affect the evacuation efficiency and the fire extinguishing activities of the fire brigade inside the tunnel, the temperature sensor must be able to search and find the locations and directions of the fires correctly.

Thermal Gradient Formed by Large Pore Layer on the Sea Bottom and Estimation of Diffusivity Coefficient

The specific objective of this research is to investigate the characteristics of temperature changes between sea water and the covered material on the sea bottom, aiming to delineate the formation of thermal gradient due to the construction of large pore layer on the sea bottom. Field observations of water quality were conducted consecutively, and the formation of thermal gradient and the diffusivity coefficient were investigated based on the observation data. It is understood that the diffusivity coefficient in the large pore layer is smaller than that in the bottom sediment, resulting in the formation of a strong stratification. The large pore layer plays a major role in suppressing the increase in temperature of the bottom sediment.

Study on the regional characteristics of the temperature changes in China based on complex network

To analyze the regional characteristics of temperature changes in China, by using the daily mean temperature series from 1961 to 2002 of 435 weather stations in China, we set up the temperature fluctuant networks, calculate the topology statistics of every station, and present the special distribution graph of all stations. We find that the degrees of RRD, RDD, DRR, DDR, DrR are extraordinarily high, and the occurrence probability of temperature fluctuation represented by these 5 nodes is greater, which is helpful for forecasting the trend of temperature changes. Then,from the distribution graph of the degrees of these 5 nodes in all the 435 stations, we define them by the symbols as countrywide model, hypo-countrywide model, eastern model, blend model, and western with southern model. The coefficient between the degree distribution in every station and the national average degree distribution has a regional characteristics, which provide us with the feasibility for analyzing the regional characteristics in theory. From the regional characteristics of the national distribution of the average clustering coefficient, we define three kinds of significant regions of temperature changes in China: strong complex regions, weak complex regions and middle complex regions.

Regional characteristics of temperature changes in China during the past 58 years and its probable correlation with abrupt temperature change

Based on recent studies of nonlinear science, we reconstruct dynamics of National Centre of Environment Prediction （NCEP） daily temperature series from 1948 to 2005 of grids located in China with the time-delay method and then analyse the dynamics structure by using dynamical correlation factor exponent Q.Eight significant temperature change regions are obtained. The characteristics of temperature changes and frequencies of extreme temperature in these regions are discussed, and the probable correlations between temperature changes and frequencies of extreme temperature are studied. Results indicate that, 1） the temperature and frequencies of extreme high temperature in ZhunGe’Er and North China both increased during the past 58 years, while frequencies of extreme low temperature in South China decreased. Furthermore, north oscillation, south oscillation, North Pacific oscillation and El Nio-south oscillation have distinct influence on temperature changes in North China, North-East China, west of West-South China and east of West-South China, while El Nio has distinct influence on South China and South East China. 2） The reason for warming during the past 58 years might be the increase of frequencies of extreme high temperature and the decrease of frequencies of extreme low temperature. 3） The abrupt change of extreme high/low temperature in the 1970s is 3—4 years later than that of abrupt temperature change. That is to say, the process of abrupt temperature change might be the inter-grade of extreme temperature from one stationary period to another stationary one.

Temperature change characteristics and its influence by urbanization in the Yangtze River Delta

With global climate change and rapid regional urbanization,temperature and eco-environment changed significantly in the Yangtze River Delta.Based on regional meteorological data from basic/reference climatological surface stations and population data,annual and seasonal temperature change characteristics,the difference of temperature change in big cities,middle cities and small towns,and the urbanization warming and its relative contribution to the total amounts of temperature change was analyzed covering the periods from 1959 to 2005 and from 1981 to 2005.The result indicates that in the past 47 years and 25 years,annual mean temperature,annual mean maximum and minimum temperature increased significantly,with the highest warming rate in winter and spring,and the lowest warming rate in summer.For all types of stations,the annual and seasonal mean temperature,mean maximum and minimum temperature generally increased in the two periods of time.The warming rate in big cities was significantly higher than that in middle cities and small towns,and urbanization warming was almost in annual and seasonal temperature in big cities.The warming rate of urbanization and its relative contribution to the total amounts of temperature change was highest in mean minimum temperature,and lowest in mean maximum temperature.From 1959 to 2005,the warming rate in small towns was close to that in middle cities,and the influence of urbanization on the temperature in middle cities was small,but from 1981 to 2005,the warming rate in middle cities was higher than that in small towns,and the warming rate of urbanization for middle cities was significant.In the Yangtze River Delta,the changing trend and warming rate of temperature,the warming rate of urbanization and its relative contribution to the total amounts of temperature change were basically consistent with that in other places.Causes for the differences between our result and those found by other researchers are likely to be related to regional extent,the criteria for defining urban and contrasting stations,the different influence of urbanization on the contrasting stations,station network density,analytical methods,time periods,and etc.

Numerical Simulation of Wire-Rod Hot Continuous Rolling Process with Multi-Field Coupling

High speed wire-rod rolling is a typical large deformation process which includes geometry, material and boundary condition non-linearity, thus it belongs to a highly nonlinear problem. The finite element models of the billet and the rollers in the intermediate rolling region had been established based on actual sizes by using 3-D thermo-mechanical coupling FEM and advanced contact analysis technology. The deformation field, stress, strain, temperature field and rolling force of the billet were calculated and analyzed in the rolling passes precisely. The distribution and change characteristics of temperature had been discussed especially. The results of the simulation are reliable and precise, which are useful for practical manufacture and the optimization of process-parameters.

Characteristics of temperature changes and distributions in a flat-roof sloping greenhouse under ventilation

Characteristics of temperature changes and distributions in a flat-roof sloping greenhouse under ventilation

NUMERICAL SIMULATION HEAT TRANSFER IN THE SLAB TUNDISH

The article presents the results of computer simulations of heat transfer in a slab tundish. The tundish was equipped with a dam with two holes. The authors employed the CFD (Computational Fluid Dynamics) numerical modelling technique to demonstrate the effect of change of steel temperature flow to tundish on the distribution of temperature field. The computer simulations were performed for non-steady conditions. As a result of computations, time characteristics of temperature change and fields of temperature for slab tundish were obtained. Results of simulation were examined through industrial experiment.

Study on ground temperature change and characteristic response of engineering geology of permafrost along Qinghai-Tibet Railway

Along with the global warming in the recent scores of years, comparatively big changes have taken place in the weather and other environmental conditions of the permafrost area in the Qinghai-Tibet Plateau, and very big changes have also occurred in the engineering geological conditions of the permafrost area. Based on a large volume of field survey data, this paper discusses the regularities of horizontal and vertical distribution of permafrost, with its focus of analysis on the temperature change characteristics of the soil in different frozen-soil zones, as well as presents simulation analysis and research for the engineering geologic characteristic response changes that would occur in the future when the temperature of the frozen soil in different zones rises by 1 and 2.6degreesC respectively, which will have a tremendous impact on the stability of constructional work.

Neutronic Design of Pulse Operation Simulating Device for In-pile Functional Test of Fusion Blanket by MCNP

The pulse operation of a fusion reactor can be simulated in a fission reactor by controlling the neutron flux entering a test section by using a rotating “hollow cylinder with window” made of hafnium. The rotating cylinder is installed between the test section and the fixed outer neutron absorber cylinder and is also made of hafnium with an opening in the direction to the core center. For gathering engineering data for the tritium breeding blanket such as characteristics of temperature change, tritium release and recovery, etc., it is desirable that the ratio of minimum to maximum thermal neutron fluxes is greater than 1:10. Design calculations were performed for the test assembly which considered local neutronic effects and the mechanical constraints of the device. From the results of these calculations, the ratio of minimum to maximum thermal neutron flux under irradiation would be about 1:10 using a pulse operation simulating device which has a thickness of 6.5 mm and a 150° window angle for the rotating hollow cylinder and 5.0 mm in thickness of fixed neutron absorber.