scholarly journals Sag and Tension of 275 kV Transmission Line using Catenary

2019 ◽  
Vol 2 (3) ◽  
pp. 15-20
Author(s):  
Dicky Novriandi ◽  
Azriyenni Azhari Zakri ◽  
Edy Ervianto
Keyword(s):  
Tensile Stress ◽  
Ambient Temperature ◽  
Transmission Line ◽  
Minimum Temperature ◽  
Maximum Tensile Stress ◽  
Maximum Temperature ◽  
Maximum Current ◽  
Current Minimum ◽  
Conducting Wire ◽  
Tension Analysis

This research will develop a catenary method to determine the sag and tension analysis on the 275 kV transmission line conductors. The catenary method is dependent on the equation of the weight of the conductor, the maximum tensile stress of the conducting wire, the length of the span, and the maximum sag of the conductor. The method will be used in determining the value of sag and tension with the design of the model using software AutoCAD. The results of research for the same tower sag height of 6.86 m, with a tension of 4610.83 kg and a conductor length of 401.06 m, while sag for the tower is not the same height of 8.14 m, with a tension of 4612.84 kg, and changes in conductor length 401.06 m. The increase in current causes the sag value to increase, when the minimum current sag value is 6.9828 m, and the maximum current sag value increases to 8.44 m. While the tension will decrease along so that temperature is increased the current minimum pressure of 4531.27kg, and at the time of maximum tension of 3749.728kg. Sag and tension are also affected by ambient temperature when the minimum temperature is 20 ℃ sags are 6.8621 m and when the maximum temperature is 40 ℃ sag increases to 7.793492 m. Tension will decrease with each increase in temperature when the minimum temperature is 20 ℃ tension 4610.538 kg when the maximum temperature is 40 ℃ the tension is reduced to 4062.345 kg.

scholarly journals Vulnérabilité Future Des Systèmes De Productions Agricoles Face Aux Changements Climatiques Dans Le 4ème PDA : Cas Des Communes De Djidja Et De Djougou

2021 ◽  
Vol 25 (1) ◽  
pp. 445
Author(s):  
AWO Sourou Malikiyou ◽  
ALE Agbachi Georges ◽  
YABI Ibouraïma
Keyword(s):  
Climate Change ◽  
Minimum Temperature ◽  
Agricultural Production ◽  
Production Systems ◽  
Methodological Approach ◽  
Maximum Temperature ◽  
A Value ◽  
Current Minimum ◽  
Maximum Temperatures ◽  
Changements Climatiques

La variabilité climatique dans les communes de Djidja et de Djougou engendre des conséquences aussi bien sur les niveaux de productivités, de production que sur les revenus des exploitants agricoles. L’objectif de cette recherche est d’étudier la vulnérabilité future des systèmes de productions agricoles face aux changements climatiques dans les Communes de Djidja et de Djougou.L’approche méthodologique utilisée comprend la collecte des données, leur traitement et l’analyse des résultats. Les enquêtes ont été faites dans les villages choisis sur la base de critères bien définis (la taille de la population agricole et son implication dans la production agricole). La méthode de D. Schwartz (1995, p. 94) a permis de constituer l’échantillon de 377 producteurs. Enfin, une projection climatique sur la période 2019-2050/2075 est faite au moyen du logiciel climatique « Climate explorer ».Il ressort des résultats de l’étude que, dans la commune de Djougou, la variation au niveau de la température minimale actuelle (RCP8.5) est comprise entre -1,62°C en 1992 et 2,29°C en 2075. La température maximale quant à elle varie entre -1,40°C en 1994 à 2,18°C en 2075. C’est à partir de 2071 que l’augmentation de la température minimale va dépasser les 2°C et si rien n’est fait cette hausse va s’accroître et devenir permanente. De même, dans la commune de Djidja, la température minimale la plus élevée est observée en 2075 avec des variations de 1 à 2°C pour les RCP4.5 et RCP8.5. Au niveau de la température maximale, l’année la moins chaude est 1992 (-1,33mm/jour) pour RCP8.5 et 1991 (-1,02mm/jour) pour RCP4.5. La même évolution s’observe au niveau des températures maximales. L’année 1992 reste la plus déficitaire avec une chute de -1,60°C et l’année la plus excédentaire sera l’année 2075 avec une hausse de 2,18 mm par jour, sur la période 1992-2080. La corrélation est observée en 2042 avec une valeur de 0,322 mm par jour. L’examen des résultats révèle que les valeurs des paramètres climatiques à savoir précipitations et évaporation sont à la hausse sur la période 1980-2080 dans la commune de Djidja. Suivant la trajectoire actuelle, RCP8.5, les années les plus arrosées sont 2037, 2070 et 2073 avec respectivement des variations égales à 0,17mm et 0,27mm de pluie par jour. Face à ces difficultés, les populations agricoles adoptent des mesures pour contrer les contraintes climatiques.ABSTRACTClimatic variability in the communes of Djidja and Djougou has consequences both on the levels of productivity and production and on the income of farmers. The objective of this research is to study the vulnerability of agricultural production systems to climate change in the Communes of Djidja and Djougou.The methodological approach used includes data collection, processing and analysis of the results. The surveys were carried out in the villages chosen on the basis of well-defined criteria (the size of the agricultural population and its involvement in agricultural production). The method of D. Schwartz (1995, p. 94) made it possible to constitute the sample of 377 producers. Finally, a climate projection over the period 2019-2050 / 2075 is made using the climate software "Climate explorer".The results of the study show that, in the municipality of Djougou, the variation in the current minimum temperature (RCP8.5) is between -1.62 ° C in 1992 and 2.29 ° C in 2075. The maximum temperature varies between -1.40 ° C in 1994 to 2.18 ° C in 2075. It is from 2071 that the increase in the minimum temperature will exceed 2 ° C and if nothing is In fact, this increase will increase and become permanent. Similarly, in the municipality of Djidja, the highest minimum temperature is observed in 2075 withvariations of 1 to 2 ° C for RCP4.5 and RCP8.5. At maximum temperature, the coolest year is 1992 (-1.33mm / day) for RCP8.5 and 1991 (-1.02mm / day) for RCP4.5. The same development can be observed at the level of maximum temperatures. The year 1992 remains the most in deficit with a fall of -1.60 ° C and the year the most in surplus will be the year 2075 with an increase of 2.18mm per day, over the period 1992-2080. The correlation is observed in 2042 with a value of 0.322 mm per day. Examination of the results reveals that the values of climatic parameters, namely precipitation and evaporation, are on the rise over the period 1980-2080 in the municipality of Djidja. Following the current trajectory, RCP8.5, the wettest years are 2037, 2070 and 2073 with respectively variations equal to 0.17mm and 0.27mm of rain per day. Faced with these difficulties, agricultural populations are adopting measures to counter climatic constraints. Keywords: Djidja, Djougou, vulnerability, production system, agriculture, climate change.

scholarly journals Research on Mechanical Performance of CRTS III Plate-Type Ballastless Track Structure under Temperature Load Based on Probability Statistics

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhiwu Yu ◽  
Ying Xie ◽  
Xiuquan Tian
Keyword(s):  
Tensile Stress ◽  
Mechanical Performance ◽  
Extreme Values ◽  
Maximum Tensile Stress ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Track Structure ◽  
Ballastless Track ◽  
Temperature Load

CRTS III (China Railway Track System III) slab ballastless track structure is one of the high-speed railway ballastless track structures which has Chinese independent intellectual property rights. The mechanical performance of CRTS III slab ballastless track structure under temperature load has not been clear yet. Therefore, through temperature field model and temperature load values selected by statistics analysis based on long-term meteorological data, the mechanical performance of ballastless track structure is studied under two typical working conditions with different safety probability. It is found that the daily extreme values of monthly axial uniform temperature and the daily maximum temperature gradient obey certain statistical laws. In addition, the maximum tensile stress of the self-compacting concrete layer is located in the middle and edge of the slab bottom and the side of the slab. The maximum tensile stress of the base plate is located at the edge of the surface of the layer and the inner edge of the limiting groove. The interface normal tensile stress is located at the end and corner of the interface. Furthermore, maximum stress increases with the increase of safety probability.

On-Line Monitoring of Charge Unit by Using Fiber Bragg Grating Temperature Sensors

2012 ◽  
Vol 503-504 ◽  
pp. 1672-1678
Author(s):  
Zhao Yang ◽  
Xiao Ping Xu ◽  
Chuan Li ◽  
Yan Chen ◽  
Jiang Chun Xu ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Fiber Bragg Grating ◽  
Minimum Temperature ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Bragg Grating ◽  
Temperature Changes ◽  
Temperature Range ◽  
On Line

The charge unit supply power when the power is cut off. It has been the necessary components in every type of substations to ensure the continuous operations of electric relays, automatic devices and circuit breakers. By using contacting electrical insulating Fiber Bragg Grating temperature sensor, the monitored equipment can be measured and controlled under the safe temperature. The temperatures of three fans and environment have been surveyed since June 6, 2010, in the charge unit of Yanjin substation’s main control room. The real-time monitoring of 24-hours indicates that the temperature changes in the range of 1°C. At the long-term of 479 days, the average daily minimum temperature range of three fans is 12.48°C, and the maximum range is 23.07°C. The maximum temperature is 39.14°C on April 30, 2011, and the minimum temperature is 23.98°C on January 10, 2011. The daily average of ambient temperature range is 12.04 °C, the maximum temperature is 38.38 °C on July 16, 2010, and the minimum temperature is 26.34 °C on January 9, 2011. The maximum difference between the temperature of fan and the ambient temperature is 7.60 °C on October 23, 2010. According to the relevant standards and monitoring results, the maximum threshold of fan temperature is defined to 85°C, and the threshold of temperature rise is 20°C.

scholarly journals Spatiotemporal Evolution of Fractional Vegetation Cover and Its Response to Climate Change Based on MODIS Data in the Subtropical Region of China

2021 ◽  
Vol 13 (5) ◽  
pp. 913
Author(s):  
Hua Liu ◽  
Xuejian Li ◽  
Fangjie Mao ◽  
Meng Zhang ◽  
Di’en Zhu ◽  
...  
Keyword(s):  
Vegetation Cover ◽  
Minimum Temperature ◽  
Maximum Temperature ◽  
Distribution Area ◽  
Spatiotemporal Pattern ◽  
Climate Factors ◽  
Important Indicator ◽  
Fractional Vegetation Cover ◽  
Annual Minimum Temperature ◽  
Total Study Area

The subtropical vegetation plays an important role in maintaining the structure and function of global ecosystems, and its contribution to the global carbon balance are receiving increasing attention. The fractional vegetation cover (FVC) as an important indicator for monitoring environment change, is widely used to analyze the spatiotemporal pattern of regional and even global vegetation. China is an important distribution area of subtropical vegetation. Therefore, we first used the dimidiate pixel model to extract the subtropical FVC of China during 2001–2018 based on MODIS land surface reflectance data, and then used the linear regression analysis and the variation coefficient to explore its spatiotemporal variations characteristics. Finally, the partial correlation analysis and the partial derivative model were used to analyze the influences and contributions of climate factors on FVC, respectively. The results showed that (1) the subtropical FVC had obvious spatiotemporal heterogeneity; the FVC high-coverage and medium-coverage zones were concentratedly and their combined area accounted for more than 70% of the total study area. (2) The interannual variation in the average subtropical FVC from 2001 to 2018 showed a significant growth trend. (3) In 76.28% of the study area, the regional FVC showed an increasing trend, and the remaining regional FVC showed a decreasing trend. However, the overall fluctuations in the FVC (increasing or decreasing) in the region were relatively stable. (4) The influences of climate factors to the FVC exhibited obvious spatial differences. More than half of all pixels exhibited the influence of the average annual minimum temperature and the annual precipitation had positive on FVC, while the average annual maximum temperature had negative on FVC. (5) The contributions of climate changes to FVC had obvious heterogeneity, and the average annual minimum temperature was the main contribution factor affecting the dynamic variations of FVC.

scholarly journals Strong controls of daily minimum temperature on the autumn photosynthetic phenology of subtropical vegetation in China

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Peixin Ren ◽  
Zelin Liu ◽  
Xiaolu Zhou ◽  
Changhui Peng ◽  
Jingfeng Xiao ◽  
...  
Keyword(s):  
Climate Change ◽  
Minimum Temperature ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Time Lag ◽  
Evergreen Forest ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Study Region ◽  
Cumulative Precipitation

Abstract Background Vegetation phenology research has largely focused on temperate deciduous forests, thus limiting our understanding of the response of evergreen vegetation to climate change in tropical and subtropical regions. Results Using satellite solar-induced chlorophyll fluorescence (SIF) and MODIS enhanced vegetation index (EVI) data, we applied two methods to evaluate temporal and spatial patterns of the end of the growing season (EGS) in subtropical vegetation in China, and analyze the dependence of EGS on preseason maximum and minimum temperatures as well as cumulative precipitation. Our results indicated that the averaged EGS derived from the SIF and EVI based on the two methods (dynamic threshold method and derivative method) was later than that derived from gross primary productivity (GPP) based on the eddy covariance technique, and the time-lag for EGSsif and EGSevi was approximately 2 weeks and 4 weeks, respectively. We found that EGS was positively correlated with preseason minimum temperature and cumulative precipitation (accounting for more than 73% and 62% of the study areas, respectively), but negatively correlated with preseason maximum temperature (accounting for more than 59% of the study areas). In addition, EGS was more sensitive to the changes in the preseason minimum temperature than to other climatic factors, and an increase in the preseason minimum temperature significantly delayed the EGS in evergreen forests, shrub and grassland. Conclusions Our results indicated that the SIF outperformed traditional vegetation indices in capturing the autumn photosynthetic phenology of evergreen forest in the subtropical region of China. We found that minimum temperature plays a significant role in determining autumn photosynthetic phenology in the study region. These findings contribute to improving our understanding of the response of the EGS to climate change in subtropical vegetation of China, and provide a new perspective for accurately evaluating the role played by evergreen vegetation in the regional carbon budget.

scholarly journals The effect of average temperature on suicide rates in five urban California counties, 1999–⁠2019: an ecological time series analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sierra Cheng ◽  
Rebecca Plouffe ◽  
Stephanie M. Nanos ◽  
Mavra Qamar ◽  
David N. Fisman ◽  
...  
Keyword(s):  
Public Health ◽  
Suicide Rate ◽  
Minimum Temperature ◽  
The United States ◽  
Additive Models ◽  
Maximum Temperature ◽  
Mortality Data ◽  
Average Temperature ◽  
Suicide Rates ◽  
Average Maximum

Abstract Background Suicide is among the top 10 leading causes of premature morality in the United States and its rates continue to increase. Thus, its prevention has become a salient public health responsibility. Risk factors of suicide transcend the individual and societal level as risk can increase based on climatic variables. The purpose of the present study is to evaluate the association between average temperature and suicide rates in the five most populous counties in California using mortality data from 1999 to 2019. Methods Monthly counts of death by suicide for the five counties of interest were obtained from CDC WONDER. Monthly average, maximum, and minimum temperature were obtained from nCLIMDIV for the same time period. We modelled the association of each temperature variable with suicide rate using negative binomial generalized additive models accounting for the county-specific annual trend and monthly seasonality. Results There were over 38,000 deaths by suicide in California’s five most populous counties between 1999 and 2019. An increase in average temperature of 1 °C corresponded to a 0.82% increase in suicide rate (IRR = 1.0082 per °C; 95% CI = 1.0025–1.0140). Estimated coefficients for maximum temperature (IRR = 1.0069 per °C; 95% CI = 1.0021–1.0117) and minimum temperature (IRR = 1.0088 per °C; 95% CI = 1.0023–1.0153) were similar. Conclusion This study adds to a growing body of evidence supporting a causal effect of elevated temperature on suicide. Further investigation into environmental causes of suicide, as well as the biological and societal contexts mediating these relationships, is critical for the development and implementation of new public health interventions to reduce the incidence of suicide, particularly in the face increasing temperatures due to climate change.

scholarly journals Effects of Cropland Expansion on Temperature Extremes in Western India from 1982 to 2015

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 489
Author(s):  
Jinxiu Liu ◽  
Weihao Shen ◽  
Yaqian He
Keyword(s):  
Land Use ◽  
Heat Flux ◽  
Land Cover ◽  
Minimum Temperature ◽  
Negative Impact ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum ◽  
Temperature Extremes ◽  
Western India

India has experienced extensive land cover and land use change (LCLUC). However, there is still limited empirical research regarding the impact of LCLUC on climate extremes in India. Here, we applied statistical methods to assess how cropland expansion has influenced temperature extremes in India from 1982 to 2015 using a new land cover and land use dataset and ECMWF Reanalysis V5 (ERA5) climate data. Our results show that during the last 34 years, croplands in western India increased by ~33.7 percentage points. This cropland expansion shows a significantly negative impact on the maxima of daily maximum temperature (TXx), while its impacts on the maxima of daily minimum temperature and the minima of daily maximum and minimum temperature are limited. It is estimated that if cropland expansion had not taken place in western India over the 1982 to 2015 period, TXx would likely have increased by 0.74 (±0.64) °C. The negative impact of croplands on reducing the TXx extreme is likely due to evaporative cooling from intensified evapotranspiration associated with croplands, resulting in increased latent heat flux and decreased sensible heat flux. This study underscores the important influences of cropland expansion on temperature extremes and can be applicable to other geographic regions experiencing LCLUC.

Observations on 287 thunder-storms made at highfield house, near Nottingham, during the last nine years

1851 ◽  
Vol 5 ◽  
pp. 957-957
Keyword(s):  
Minimum Temperature ◽  
Maximum Temperature ◽  
Tabular Form ◽  
The Hours ◽  
The Mean ◽  
Atmospheric Phenomena ◽  
Rotatory Motion

The thunder-storms referred to in this communication are recorded in a tabular form., arranged according to their dates. In this table are given the date; the hour of the commencement of the storm; the mean height of the barometer to tenths of an inch; whether it is rising, stationary, or falling; the direction of the wind before the storm, during its continuance, and after its cessation; the maximum temperature on the day of the storm and on the day after; the minimum temperature on the night before and on the night after; and general remarks on the storms. This table is followed by remarks on particular storms recorded in it. In conclusion the author gives the results of his observations with reference to the number of storms in each year; the number in each month, with the hours at which they mostly occur in particular months; the number that have occurred with a rising, stationary, or falling barometer; the number in respect to the direction of the wind and of the current in which the storms moved; the number of storms that have occurred at the various heights of the maximum, and also of the minimum thermometer; the number in which the peculiar breeze that suddenly springs up on the commencement of thunder-storms has been well marked; the change in the direction of some of these storms, and indications of rotatory motion; and finally, the different atmospheric phenomena which have accompanied these storms.

Design and Fabrication of a Magnetocaloric Microcooler

2005 ◽  
Author(s):  
Sangchae Kim ◽  
Bharath Bethala ◽  
Simone Ghirlanda ◽  
Senthil N. Sambandam ◽  
Shekhar Bhansali
Keyword(s):  
Magnetic Field ◽  
Ambient Temperature ◽  
Temperature Change ◽  
Entropy Change ◽  
Temperature Sensors ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Alternative Technology ◽  
Temperature Conditions ◽  
Si Wafer

Magnetocaloric refrigeration is increasingly being explored as an alternative technology for cooling. This paper presents the design and fabrication of a micromachined magnetocaloric cooler. The cooler consists of fluidic microchannels (in a Si wafer), diffused temperature sensors, and a Gd5(Si2Ge2) magnetocaloric refrigeration element. A magnetic field of 1.5 T is applied using an electromagnet to change the entropy of the magnetocaloric element for different ambient temperature conditions ranging from 258 K to 280 K, and the results are discussed. The tests show a maximum temperature change of 7 K on the magnetocaloric element at 258 K. The experimental results co-relate well with the entropy change of the material.

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