Temperature Change Trend Research Articles

Geospatial Modeling for Investigating Spatial Pattern and Change Trend of Temperature and Rainfall

Bangladesh has been experiencing increased temperature and change in precipitation regime, which might adversely affect the important ecosystems in the country differentially. The river flows and groundwater recharge over space and time are determined by changes in temperature, evaporation and crucially precipitation. These again have a spatio-temporal dimension. This geospatial modeling research aimed at investigating spatial patterns and changing trends of temperature and rainfall within the geographical boundary of Bangladesh. This would facilitate better understanding the change pattern and their probable impacts on the ecosystem. The southeastern region, which is one of the most important forest ecosystem zones in the country, is experiencing early onset and withdrawal of rain but increasing trends in total rainfall except in the Monsoon season. This means that the region is experiencing a lower number of rainy days. However, total rainfall has not changed significantly. The differential between maximum and minimum showed an increasing trend. This changing pattern in average max and min temperature along with precipitation might cause a situation in which the species that are growing now may shift to suitable habitats elsewhere in the future. Consequently, the biodiversity, watersheds and fisheries, productivity of land, agriculture and food security in the region will be affected by these observed changes in climate.

Comparative Analysis of Air Temperature Change Trends among Different Ecosystems in Recent Decades in Northeast China

Global warming is a major environmental problem in recent social development of human being.And to best understanding variant aspect of the temperature risen in different ecosystems is also a foundation for serving the local ecology and environmental assessment and economic planning in regional scale.Then,this paper employed Rank Correlation Methods(Mann-Kendall test)to analyze temperature change trends comparatively among different ecosystems(Agricultural ecosystem/Forest ecosystem/Dry grassland ecosystem/Meadow steppe ecosystem)based on annual mean temperature data from1961 to 2012 in the Northeast of China.Among them,the forest ecosystem reflects the features of mountain area;Dry grassland ecosystem reflects characteristics of the plateau in the Eurasian steppe eastern;Meadow steppe ecosystem reflects transition zone characteristics between the forest and steppe;Agricultural ecosystem reflects the characteristics of the northern of the Northeast plain.Effect of zonal latitude basic excluded,the temperature change is one of the important indexes of main ecosystem environment change in Northeast china in recent decades.Results showed that the change of annual highest temperature was the most significant;the second was annual mean temperature;the last was annual minimum temperature.It had a very good consistency in the temperature change trend among different ecosystems,while change trend of the 3 index was different in the same one.Annual mean temperature of meadow steppe ecosystem was the most significant;Rate of rise was the largest(0.44/10a)and abrupt point was the earliest.Annual highest temperature of agricultural ecosystem has been on the rise,especially the tendency was more significant in the 1990 s,and abrupt point was the earliest.

The use of Digital Image Correlation to correct the thermoelastic curves in static tests

Many studies have been carried out with the aid of thermal scanners for the analysis of the thermoelastic effect on materials. In particular, for tensile stresses, the gradient is negative and the thermal variations are proportional to the stress applied in the purely elastic phase. Thermoelastic analysis of materials from the static tests have shown that it is possible to detect information on the dynamic (fatigue) behavior.One of the main problems that occur in following the local thermal behavior in a static test is that of dimensional correction and tracking of the measuring point (spot). These do not allow to follow the same investigated area, that progressively undergoes a displacement as load increases.The purpose of this work, based on previous experiences, is to implement an algorithm and to define a procedure that allows the tracking of the area thermally investigated that, as the load increasing, inevitably undergoes a displacement. The radiometric spots on the specimen, selected at the beginning of test, are progressively updated by following thermographic frames. The displacement information derived from the Digital Image Correlation (D.I.C.), simultaneously was applied on the same specimens. This procedure can better define the trend of temperature changes during the static tensile test and can be used to measure the stress concentration factors in notched specimens.

The Influence Study of Ultrasonic honing parameters to workpiece surface temperature

Ultrasonic vibration honing(UVH), a machine technology, has a lot of advantages. Lower grinding temperature is a significant character and is beneficial for both processing and workpiece surface. But the high temperature caused by big honing pressure becomes the main factor to produce workpiece heat damage in grinding zone. In various honing parameter combinations, the showing effect is different. Based on the thermodynamics classical theory, established the heat transfer equation for grinding zone, simplified the model and obtained the two-dimenssion temperature field expression for workpiece, then simulated the temperature changing trend in a variety of conditions. It is shown that themain temp is in a range of 700K to 1200K. In addition, the variation is huge for every parameter. The study provides a theoretical basis for deeply seeking reasonable machining parameter and obtaining better workpiece quality.

Proyección de cambios en la temperatura superficial del mar del Golfo de California y efectos sobre la abundancia y distribución de especies arrecifales

The Gulf of California is important because of its high biodiversity and because it is a key area for artisanal fisheries in Mexico. There are current concerns regarding threats to the Gulf, such as global warming, that have caused major changes in marine communities. Consequently, the aim of this study was to estimate the possible impact of increasing ocean temperature on key species. Potential effects of such increase on reef species are thus estimated in this paper. In order to prepare this estimate, sea surface temperature (SST) was obtained from the NOAA database, and a temperature change trend model was constructed. Biological data was obtained from visual censuses of six regions within the Gulf between 2005 and 2007. A stepwise linear model was used to forecast potential changes in species abundance and distribution. It is estimated that by 2050 average temperature will increase 0.63°C, causing abundance of species of economic value to significantly decrease south of 25° N. Finally, the response of the 20 most abundant fish species in the Gulf was modeled to estimate changes at community structure level. The simulation shows an imbalance in the function and structure of assemblages. Clearly, increasing sea temperature will bring an imbalance in the composition and the ecological function of the reef systems gradually changing the relative abundances of species. Therefore, the implementation of effective monitoring programs of communities would be an essential tool to detect future effects of global warming.

반열풍식 커피 로스터기의 로스팅 과정 자동화 구현을 위한 실험적 연구

An experimental study on the automation of the coffee roasting process was conducted. For this study, a temperature sensor, controllers, and motors were added to a manually operated coffee roaster. The temperature, time, and exhausting damper control were selected as the control parameters. The thermocouple measurements were severely influenced by the thermocouple size and location of the roaster. As a result, the standard thermocouple size and location of the roaster were experimentally set to show a similar trend of temperature change by using a previously installed thermometer. A standard roasting process was chosen through repeated roasting experiments and the advice of a roasting expert. The automation of the roasting process was successfully executed using temperature criteria, such as the bean input and first and second crack occurrence, and by controlling the exhausting damper opening time. The control parameters and roaster skills can be used for similar types of roasters for process automation.

Core Temperature Evaluation in Different Body Parts in Patients Undergoing Laparoscope Surgery under Total Intravenous Anesthesia*

Purpose The trend of body temperature change during laparoscopic surgery and the most adequate site for monitoring temperature measurements have not been investigated thoroughly. In this study body temperature change during laparoscopic surgery was measured and measurements of the tympanic, esophageal, and nasopharyngeal core temperatures in surgical patients with total intravenous anesthesia were compared. Methods From February to October 2013, 28 laparoscopic surgical patients were recruited from a tertiary hospital in Seoul. The patients' core temperature was measured 12 times at ten minute intervals from ten minutes after the beginning of endotracheal intubation. Results Repeated measure of core temperatures indicated a significant difference according to body part (p=.033), time of measure (p<.001) and the reciprocal interaction between body part and time of measure (p<.027). The core temperatures were highest at tympany location, lowest at nasopharynx. The amount of temperature change was least for the esophagus (36.10~36.33℃), followed by nasopharynx and tympany. Conclusion The esophageal core temperature showed the highest stability followed by nasopharyngeal and tympanic temperature. Therefore, close observations are required between 10~20minutes after the beginning of the operation. 주요어: 심부체온, 복강경 ìˆ˜ìˆ , ì „ì •ë§¥ ì „ì‹ ë§ˆì·¨ Key words: Core temperature, Laparoscope surgery, Total Intravenous Anesthesia

A comparison of general circulation models and their application to temperature change assessments in a high-latitude agricultural area in northeastern China

The two main focuses of this study are a comparison of the general circulation models (GCMs) from Phase 5 of the Coupled Model Inter-Comparison Project (CMIP5) and an assessment of the surface air temperature under multiple climate scenarios in a high middle latitude area of China. In the past 55 years temperatures in this area have shown an obvious upward trend (a rise of 1.50 °C), and another important change during this time period was a significant alteration in tillage practices that occurred in 1986. Using methods and tools such as average deviation, the Taylor figure and the space techniques rating (SS), time sequence related coefficient, and the M2 index, a comprehensive spatial–temporal assessment was performed based on the CMIP5 models. The simulations provided by the models had certain common features, but there were also significant differences. The three best models (CanCM4, INMCM4, and IPSL-CM5A-MR) have a common characteristic: the institutions where they were developed are located at latitudes that are similar to or higher than the latitude of the study area. Future climate changes were analyzed by simulating a representative concentration pathway 4.5/8.5 (RCP4.5/RCP8.5) of emission scenarios with a multi-model ensemble. The temperatures under the RCP4.5 and RCP8.5 scenarios have a certain upward trend, with increases of 2.24 and 5.44 °C, respectively. From a spatial perspective, the distributions of the temperature change trend showed a southwest to northeast step increase under both scenarios, but the warming trend in the area of each lattice point under the RCP4.5 scenario is much lower than that of the RCP8.5 scenario. There are no obvious changes in the spatial distribution of the accumulated intensity and frequency of the regional air temperature in the three periods (2016–2035, 2036–2065, and 2066–2095) under the two scenarios.

Temperature Change in the Largest Industrial City, Korea

This study analyzed a change trend of ambient temperature over the last sixty years in the largest industrial city in Korea, Ulsan. Linear warming rates in Ulsan over the last 25 (1985 to 2009), 40 (1970 to 2009), and 60 (1950 to 2009) years were 0.0507, 0.0416, and 0.0277°C/yr, respectively. The annual average temperature (AAT) and the annual average of the daily lowest temperature (AADLT) in Ulsan increased 1.3 and 2.9°C, respectively, over the last fifty years (1960 to 2009). The increasing slopes of the AAT and AADLT over the fifty years in Ulsan were higher or much higher than those in neighboring cities and on a global scale. In the comparison analysis of daily average temperature over the most recent ten years, the highest (15.9°C) was observed in the industrial area followed by the downtown, coastal, suburban, and rural areas with 14.6, 14.5, 14.0, and 12.8°C, respectively. The number of cold days less than 5.0°C decreased, while the number of hot days higher than 20.0°C increased. The decreasing slopes in the cold days in lower latitude cities were steeper than those in higher latitude cities in Korea.

近50a武威市地气温差变化趋势及影响因子分析

近50a武威市地气温差变化趋势及影响因子分析

Trend analysis by Mann-Kendall test for precipitation and temperature for thirteen districts of Uttarakhand

The present study is mainly concerned with the changing trends of rainfall and temperature of all the thirteen districts of the state Uttarakhand. The state lies on the southern slope of the Himalayan range and the climate and vegetation vary greatly with elevation, from the glaciers at the highest elevations to subtropical forests at lower elevations. In the present study, we have tried to analyze the most important climatic variables precipitation and temperature, for analyzing the trend in the area. For this, daily rainfall data of 41 years from 1971 to 2011 and minimum and maximum temperature data of 37 years from 1971 to 2007 has been processed in the study to find out the monthly variability of rainfall and temperature for which Mann-Kendall (MK) Test has been used together with the Sen’s Slope Estimator for the determination of trend and slope magnitude. Monthly precipitation and temperature trend has been identified here to achieve the objective which has been shown by 41and 37 years of data. There are increasing trends of precipitation and temperature in some months and decreasing trends in some other months for all the thirteen districts of Uttarakhand obtained from these statistical tests suggesting overall insignificant changes in the area.

Thermal conditions in Bydgoszcz Region in growing seasons of 2011–2050 in view of expected climate change/ Warunki termiczne w rejonie Bydgoszczy w okresie wegetacyjnym w latach 2011–2050 w świetle przewidywanej zmiany klimatu

Abstract The paper presents an analyse of the scenario of expected changes in monthly mean air temperature of months in the growing season (April-September) and growing seasons of 2011-2050 in Bydgoszcz Region. Prediction of thermal conditions is made using regional climate model RM5.1 with boundary values taken from global model ARPEGE. When compared with the reference period 1971-2000, an increase of mean air temperature should be expected in most months and growing seasons of the years 2011-2050. The biggest positive change in the mean monthly temperature is predicted for July (1.5°C) and August (1.2°C). In 2011-2050 significant increase trends of air temperature change can be expected in April, June and August. According to the thermal classification proposed by Lorenc, normal, slightly warm and slightly cool months and growing periods will dominate. The frequency of normal and slightly cool growing periods will decrease and the frequency of slightly warm growing periods will increase.

Study on Curing Temperature of Dry-Type Air-Core Reactor Based on Fiber Bragg Grating

干式空心电抗器的固化温升作为其生产流程中最关键环节之一，其环境温度的变化直接影响到干抗的匝间绝缘。本文结合厂家多年固化温升的经验，设计了一套基于Bragg光纤光栅的在线监测系统，该系统可对干式空心电抗器包封层的温度和应变进行在线测量。通过对干抗的现场固化温升实验的在线测量，得出了各包封层的温度和应变变化趋势。该研究成果将为变电站的干式空心电抗器实时监测提供重要的理论依据和设备支持。Curing temperature rise of dry-type air-core reactor is one of the most key links in the production process. The environment temperature changes directly affect the turn-to-turn insulation of dry resistance. In this paper, combining the manufacturers’ many years of experience of curing tem-perature rise, it designs a set of on-line monitoring system based on fiber Bragg grating. This sys-tem can do on-line measurement of dry-type air-core reactor temperature and strain of the coating layer. Through the online measurement of the curing temperature experiments of dry resistance, change trends of temperature and strain in each coating layer can be concluded. The results of the study will provide important theoretical basis and equipment support for the real-time monitoring of dry-type air-core reactor in transformer substation.

Characteristics of climate change in southwest China karst region and their potential environmental impacts

Global warming, due to the enhanced greenhouse effect, is likely to have significant effect on the hydrological cycle, which would result in more evaporation, more precipitation, and uneven distribution of precipitation around the globe. Some parts of the world may see significant reduction in precipitation, or major alterations in the timing of wet and dry seasons, and increases in both floods and droughts. In China, a warming trend has been observed across the mainland region during the past 50 years, with an increasing temperature of about 0.2–0.3 °C/10 year in northern and less than 0.1 °C/10 year in southern China. To understand the characteristics of climate change, this study has conducted statistical analysis on climate parameters from 12 representative meteorological stations in southwest China karst region. The non-parametric Mann–Kendall rank statistic method and the Pettitt–Mann–Whitney change point statistics were used, respectively, for the change trend and change point analyses of daily temperature and precipitation at each station. The 5-year moving averages of 11 climate parameters showed a clear increase in the maximum and minimum annual average temperature in southwest China, however, no consistent increase for precipitation. In addition to temperature and precipitation, changes in the atmospheric pressure, wind speed, and cloud cover were also observed from this study. Changes in climate characteristics will or have altered the hydrologic cycle in the region, which would induce more frequent drought and flood, redistribution of water resources, rocky desertification, and carbon balance, and will ultimately have great impacts on the social, economic, and environmental life in the region.

Prediction of Ship Main Engine Exhaust Gas Temperature Using AR Model

In order to forecast the malfunctional state of main power plant on ships through predicting the trend of unsteadily changed thermal performance parameters in main power plant system, this paper established AR model for thermal performance parameters using time series analysis method, by which to predict the change trend analysis of thermal performance parameters, and comparing the predicted values and the measured values. The actual application case of predicting a main engine’s exhaust temperature has been validated by using of the AR model, and results showed that: AR model can accurately predict the change trend of smoke temperature, and the prediction precision is higher, the average relative error was 0.25%.

Mathematical modeling and analysis of thermodynamic processes in a twin-rotor piston engine

In order to study the major performance indicators of the twin-rotor piston engine (TRPE), Matlab/simulink was used to simulate the mathematical models of its thermodynamic processes. With consideration of the characteristics of the working processes in the TRPE, corresponding differential equations were established and then simplified by period features of the TRPE. Finally, the major boundary conditions were figured out. The changing trends of mass, pressure and temperature of working fuel in the working chamber during a complete engine cycle were presented. The simulation results are consistent with the trends of an actual working cycle in the TRPE, which indicates that the method of simulation is feasible. As the pressure in the working chamber is calculated, all the performance parameters of the TRPE can be obtained. The major performance indicators, such as the indicated mean effective pressure, power to weight ratio and the volume power, are also acquired. Compared with three different types of conventional engines, the TRPE has a bigger utilization ratio of cylinder volume, a higher power to weight ratio and a more compact structure. This indicates that TRPE is superior to conventional engines.

Measuring Near‐Surface Soil Thermal Properties with the Heat‐Pulse Method: Correction of Ambient Temperature and Soil–Air Interface Effects

Large temperature gradients and proximity to the soil–air interface affect the measurement accuracy of thermal properties with the heat‐pulse probe (HPP). The objective of this study is to improve the HPP methodology for measuring soil heat capacity (C) and thermal conductivity (λ) in the surface soil layer by reducing the effects of ambient temperature variation and the soil–air interface. Thermal properties of eight soil layers (0–6, 2–6, 6–12, 12–18, 18–24, 24–30, 30–36, and 36–42 mm) were measured with the HPP in a loamy sand soil in two experiments with varying moisture conditions. Results were compared with values estimated with the de Vries models. Temperature drift caused by natural warming and cooling was removed from the observed trend of ambient temperature change with time. The influence of the soil–air interface was taken into account with a new solution using pulsed infinite line source theory with adiabatic boundary conditions. When ambient temperature change was considered, the HPP were capable of providing reasonable thermal property results at soil depths greater than 6 mm. For the 0‐ to 6‐mm depth layer, the HPP signals were affected simultaneously by ambient temperature drift and the soil‐air interface, and mixed scenarios were produced. Around midday, the HPP temperature by time curves were distorted so seriously that the effect of ambient temperature drift could not be removed. At other times, large errors were observed in the estimated C and λ data, even when ambient temperature drift was removed. When the effect of the soil–air interface was accounted for, however, C and λ measurement accuracies in the 0‐ to 6‐mm layer were improved significantly. The RMSE of C was reduced from 0.43 MJ m−3 °C−1 to 0.29 MJ m−3 °C−1 in Exp. 1, and from 0.52 MJ m−3 °C−1 to 0.34 MJ m−3 °C−1 in Exp. 2. Significant error reduction was also observed in λ measurements. Thus, to obtain accurate field measurements of shallow soil thermal properties, the ambient temperature drift and the impact of the soil–air interface must be properly taken into account.

Experimental study on spray combustion characteristics of gasoline–diesel blended fuel in a controllable active thermo-atmosphere

The lift-off flame of gasoline/diesel blend fuel spray in controllable active thermo-atmosphere (CATA) was captured by a high speed camera to investigate the auto-ignition characteristics of blend fuel, meanwhile a database for further simulation work was provided. The experimental results showed that the influence of co-flow temperature on spray lift-off flame has two opposite trends: Under higher co-flow temperature, the flame lift-off height increases with the increase of blended ratio of diesel, and the ignition delay gets longer; when the co-flow temperature is lower, the increment of diesel ratio in blend fuel leads to decrement in lift-off height, and the auto-ignition delay becomes shorter. According to the results, the equilibrium temperature “Te” was defined to represent the co-flow temperature, where diesel and gasoline ignited spontaneously, and under the test conditions of this paper, it is around 1117K. The exact value of equilibrium temperature of diesel and gasoline fuel under the conditions of an internal combustion engine (ICE) still needs to be verified by further experimental studies, but the change rules and trend of the equilibrium temperature that proposed in this paper should be applicable to real engines.

Based on Wireless Sensor Technology for Substation Equipment Temperature Monitoring System

in view of the substation equipment temperature measuring work, the existence of low accuracy of temperature measurement, data real-time performance, large work volume on manual operation, the temperature of the wireless sensor monitoring technique, the 2.4 GHZ wireless network technology, build a wireless temperature monitoring system, substation equipment temperature and the temperature rise of accurate, reliable and real-time on-line monitoring. Real-time monitoring data, intuitive display are in tabular and graphical form. Have the equipment temperature measurement data, temperature change trend analysis, data query and management, over temperature alarm to remind, etc. Real-time temperature data can be convenient access to the substation set control center, to ensure safe and reliable operation of the transformer substation, for substation monitoring and maintenance of equipment operation to provide data support, effectively prevent substation equipment oxidation, burning and other accidents.

Elevation-dependent relationships between climate change and grassland vegetation variation across the Qinghai-Xizang Plateau

As one of the most sensitive regions to climate change, the Qinghai-Xizang Plateau has been widely investigated as one unity for impacts of climate change on alpine grassland. However, previous findings might be confounded by distinct climate sensitivities at different elevations and different regional climates between Qinghai Province and Xizang Province, which lie at the two sides of Tanggula Mountains. In this study, we explored change trends of grassland vegetation, temperature and precipitation in growing season from 1982 to 2011, and elevation-dependent effects of climate change on grassland vegetation in the two provinces separately. The plateau grassland greenness gained improvement under climate warming and wetting during the past 30 years, especially in Qinghai Province. Temperature increased significantly with a warming magnitude of more than 1.5 degrees C over the plateau grassland. The interannual change of precipitation showed contrary trends between the two provinces. The main climate factor driving the grassland vegetation variation varied between the two provinces, with temperature being the main factor in Qinghai Province and precipitation being the main factor in Xizang Province. In particular, a more significant correlation between climate change and grassland vegetation variation was found at higher elevations, which reveals higher climate sensitivity in higher elevation areas of the plateau.