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Mupangwa, Walter, Lovemore Chipindu, Bongani Ncube, Siyabusa Mkuhlani, Nascimento Nhantumbo, Esther Masvaya, Amos Ngwira, Mokhele Moeletsi, Isaiah Nyagumbo et Feyera Liben. « Temporal Changes in Minimum and Maximum Temperatures at Selected Locations of Southern Africa ». Climate 11, no 4 (6 avril 2023) : 84. http://dx.doi.org/10.3390/cli11040084.
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Agriculture is threatened by ever increasing temperatures and this trend is predicted to continue for the near and distant future. The negative impact of rising temperatures on agri-food systems is also compounded by the erratic and highly variable rainfall in most parts of southern Africa. Minimum and maximum temperatures’ variability and trend analysis were undertaken using daily time series data derived from 23 meteorological stations spread across Malawi, Mozambique, South Africa and Zimbabwe. The modified Mann–Kendall and Theil–Sen slope models were used to assess temperature trends and their magnitudes. Temperature varied with location and minimum temperature was more variable than maximum temperature. Semi-arid regions had higher variation in minimum temperature compared to humid and coastal environments. The results showed an upward trend in minimum (0.01–0.83 °C over a 33–38 year period) and maximum (0.01–0.09 °C over a 38–57 year period) temperatures at 9 and15 locations, respectively. A downward trend in minimum temperature (0.03–0.20 °C over 38–41 years) occurred in South Africa at two locations and Dedza (Malawi), while a non-significant decline in maximum temperature (0.01 °C over 54 years) occurred at one location in coastal dry sub-humid Mozambique. The results confirm the increase in temperature over 33–79 years, and highlight the importance of including temperature when designing climate change adaption and mitigation strategies in southern Africa and similar environments.
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Lekea, Angella, et Wynand J. vdM Steyn. « Performance of Pavement Temperature Prediction Models ». Applied Sciences 13, no 7 (24 mars 2023) : 4164. http://dx.doi.org/10.3390/app13074164.
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Appropriate asphalt binder selection is dependent on the correct determination of maximum and minimum pavement temperatures. Temperature prediction models have been developed to determine pavement design temperatures. Accordingly, accurate temperature prediction is necessary to ensure the correct design of climate-resilient pavements and for suitable pavement overlay design. Research has shown that the complexity of the model, input variables, geographical location among others affect the accuracy of temperature prediction models. Calibration has also proved to improve the accuracy of the predicted temperature. In this paper, the performance of three pavement temperature prediction models with a sample of materials, including asphalt, was examined. Furthermore, the effect of calibration on model accuracy was evaluated. Temperature data sourced from Pretoria were used to calibrate and test the models. The performance of both the calibrated and uncalibrated models in a different geographical location was also assessed. Asphalt temperature data from two locations in Ghana were used. The determination coefficient (R2), Variance Accounted For (VAF), Maximum Relative Error (MRE) and Root Mean Square Error (RMSE) statistical methods were used in the analysis. It was observed that the models performed better at predicting maximum temperature, while minimum temperature predictions were highly variable. The performance of the models varied for the maximum temperature prediction depending on the material. Calibration improved the accuracy of the models, but test data relevant to each location ought to be used for calibration to be effective. There is also a need for the models to be tested with data sourced from other continents.
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Amelia, Afritha, Bakti Viyata Sundawa, Roslina et Rahimah Abdul Rahman. « Implementation of Environmental Parameter Control System in Green House to Increase Vegetable Production ». International Journal of Research in Vocational Studies (IJRVOCAS) 4, no 4 (31 janvier 2025) : 01–06. https://doi.org/10.53893/ijrvocas.v4i4.308.
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The use of green houses in plant cultivation is one way to approach optimal conditions for plant growth. Green houses are generally useful for protecting plants from extreme air temperatures. This requires further study of the smart features that will be built to support the concept of greenhouse agriculture. The development of automation technology is expected to help the monitoring system of parameters that affect the production of vegetable crops such as air temperature, and air humidity. These parameters will be monitored remotely using the Internet of Things (IoT) method. Based on the measurement results from the location at POLMED campus. For Medan Selayang the maximum temperature is 26.4oC and humidity is 68.8%. For the location in Medan Johor the maximum temperature is 25.4oC and humidity is 68.1%. For Medan Baru location, the maximum temperature is 25.1oC and humidity is 68.3%. For Medan Helvetia location, the maximum temperature was 24.7oC and humidity was 69%. Based on the test results, the temperature and humidity parameters can be monitored remotely by 106.4 km via the internet.
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TSIALTAS, J. T., et N. MASLARIS. « The effect of temperature, water input and length of growing season on sugar beet yield in five locations in Greece ». Journal of Agricultural Science 152, no 2 (7 janvier 2013) : 177–87. http://dx.doi.org/10.1017/s0021859612000998.
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SUMMARYFrom 1999 to 2006, 36 field experiments were conducted in five sugar beet growing areas in Greece (Larissa, Plati, Serres, Xanthi and Orestiada) to monitor yield. Locations differed significantly regarding thermal variables during the growing season with Xanthi having the most favourable thermal conditions (Tmax, average daily maximum temperature;Tmean, average daily mean temperature; GDD, growing degree days) for sugar beet growth. From early June to the end of the harvesting campaign, successive harvests were conducted. Over the years, fresh root weight and sugar yield at the last harvest of the season (FRWLH, SYLH) did not differ significantly among locations. Also, there were no significant differences among locations regarding GDD for maximum FRW and SY (GDDMFRW, GDDMSY), with the means over location estimated at 2639·9 and 2792·5 °C, respectively. Days after seeding (DAS) necessary for maximum yield (DASMFRW, DASMSY, respectively) differed among locations, with the longest period (DASMFRW206·4 days, DASMSY: 204·5 days) occurring in the northernmost location (Orestiada). Means for DASMFRWand DASMSYat the five locations were estimated at 190·4 and 188·9·days, respectively. Excluding Xanthi and combining the remaining locations, FRWLHand SYLHwere negatively correlated with the average temperatures (Tmean,TmaxandTmin, daily minimum temperature) over the growing season. The opposite was evident for Xanthi where sugar beet was grown under sub-optimal temperatures. The optimum meanTmaxof the five locations was estimated at 25·5 and 25·1 °C for FRWLHand SYLH, respectively. Elongation of the growing season, by means of early sowing, would increase yield by decreasing average temperatures (Tmean,Tmax) over the growing season in locations with the highest recorded temperatures (Larissa, Plati, Serres and Orestiada). In Xanthi, the projected temperature increase, as a result of climate change, is expected to have a positive effect on yields.
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Weinberg, Michael C. « On the location of the maximum homogeneous crystal nucleation temperature ». Journal of Non-Crystalline Solids 83, no 1-2 (juin 1986) : 98–113. http://dx.doi.org/10.1016/0022-3093(86)90060-8.
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Hermansson, Åke. « Simulation Model for Calculating Pavement Temperatures Including Maximum Temperature ». Transportation Research Record : Journal of the Transportation Research Board 1699, no 1 (janvier 2000) : 134–41. http://dx.doi.org/10.3141/1699-19.
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A simulation model has been developed to calculate the temperatures of asphalt concrete during summer. Input data to the simulation model are hourly values for solar radiation, air temperature, and wind velocity. Longwave radiation incident to and outgoing from the pavement surface is calculated from the air and pavement surface temperatures, respectively. The portion of the incident shortwave radiation absorbed by the pavement surface is calculated from the albedo of the surface. By means of a finite difference approximation of the heat transfer equation, the temperatures are calculated under the surface. Apart from radiation and heat transfer, convection losses from the pavement surface are also calculated depending on wind velocity, air temperature, and surface temperature. The formulas used for the calculation of radiation and the simulation model as a whole are validated by comparison with measurements, showing good agreement. A method for the calculation of direct solar radiation from a clear sky, at an arbitrary location and time, is used to create input data to the simulation model in order to calculate maximum pavement temperatures. The formulas used with Superpave to calculate maximum pavement temperatures are based on the assumption that there is an equilibrium when a maximum temperature is reached. Such an equilibrium assumption can be strongly questioned, and its consequences are discussed.
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DeGaetano, Arthur T., Keith L. Eggleston et Warren W. Knapp. « A Method to Estimate Missing Daily Maximum and Minimum Temperature Observations ». Journal of Applied Meteorology 34, no 2 (1 février 1995) : 371–80. http://dx.doi.org/10.1175/1520-0450-34.2.371.
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Abstract A method to estimate missing daily maximum and minimum temperatures is presented. Temperature estimates are based on departures from daily temperature normals at the three closest stations with similar observation times. Although applied to Cooperative Observer Network stations in the northeastern United States, the approach can be used with any network of stations possessing an adequate station density and period of record. Generally, 75% of the estimates for both daily maximum and minimum temperature are within 1.7°C of the observed value. Median absolute differences between estimated and observed minimum temperatures, however, tend to be greater than those associated with maximum temperatures. For minimum temperatures, median absolute differences are approximately 1.0°C, whereas for maximum temperatures these differences are near 0.5°C. The accuracy of the estimates is independent of observation time, geographic location, and observed temperature but is influenced somewhat by station density.
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Rattigan, K., et SJ Hill. « Relationship between temperature and flowering in almond : effect of location ». Australian Journal of Experimental Agriculture 27, no 6 (1987) : 905. http://dx.doi.org/10.1071/ea9870905.
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A model for the prediction of flowering date in almond requires estimates of the chilling and heat sum requirements. We estimated hourly temperatures from daily minimum and maximum temperatures. A continuous function relating hourly temperature to rate of chilling was used to calculate daily chill unit accumulations. Heat sums were measured as growing-degree-hours: the linear accumulation of hourly temperatures above a threshold temperature. Our model was tested with estimates derived from data obtained at 1 French and 2 Australian locations. The results indicate that estimates derived from data at a single location can be successfully used for other locations with different climates. The accuracy of flowering date prediction generally improves as the number of locations and years of data on which it is based increase. The predictions for the cultivars Mission and Nonpareil were within 5 days of the observed dates in 73 and 88% respectively of the locations-years examined. We concluded that the chilling requirement in almond is (mean � s.e.) 284 � 33 chill units and 3 groups of cultivars can be identified with respect to heat sum requirement in the ranges 5300-6300; 6800-7700 and 8200-8900 degree hours above 4.5�C.
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Guo, Hanwen, Zhengyuan Yang, Peiyao Zhang, Yunji Gao et Yuchun Zhang. « Experimental Investigation on Fire Smoke Temperature under Forced Ventilation Conditions in a Bifurcated Tunnel with Fires Situated in a Branch Tunnel ». Fire 6, no 12 (17 décembre 2023) : 473. http://dx.doi.org/10.3390/fire6120473.
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In this work, a number of experiments were conducted in a reduced scale bifurcation tunnel with a ratio of 1:10 to explore the influence of the position of longitudinal fires (placed in branch tunnel) on smoke temperature profile under forced ventilation. Three heat release rates, six ventilation velocities, and three fire locations were considered. The main findings are summarized below, as follows: The temperature of smoke downstream of the main tunnel decreases with the rate of ventilation and longitudinal fire location. In contrast, the smoke temperature downstream of the fire source inside the branch tunnel drops with the ventilation velocity; the maximum temperature of the flame under the ceiling of the tunnel rises with longitudinal fire location. The dimensionless longitudinal smoke temperatures downstream of the main tunnel decrease exponentially with longitudinal distance, and the same observation is found in the branch tunnel. The attenuation coefficient k in the main tunnel increases with longitudinal ventilation velocity according to a power law but does not change significantly with longitudinal fire locations. However, the exponential coefficient k′ in the branch tunnel decreases linearly with ventilation velocity, whereas it increases with longitudinal fire location inside the branch tunnel. Lastly, modified models are established for estimating the longitudinal profile of temperatures downstream of the main tunnel and branch tunnel, where the influence of the rate of ventilation and location of the fire are taken into account.
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Nasher, NM Refat, et MN Uddin. « Maximum and Minimum Temperature Trends Variation over Northern and Southern Part of Bangladesh ». Journal of Environmental Science and Natural Resources 6, no 2 (11 février 2015) : 83–88. http://dx.doi.org/10.3329/jesnr.v6i2.22101.
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Temperature is one of the pivotal climatic variables in our world climate literature. In the present study monthly, seasonal and yearly highest maximum and lowest minimum temperatures of two cities were analyzed. Mann-Kendall test and Sens Slope Estimator were used to determine the trend and slope magnitude. Chittagong, as the coastal city and Rajshahi, as Barind track were selected as a study area due to its respective geographical location. Such types of data of 52 years for Chittagong as well as 48 years for Rajshahi were collected from Bangladesh Meteorological Department (BMD). Monthly highest maximum and lowest minimum temperature data from 1950-2002 for Chittagong and 1964-2012 for Rajshahi were used for analysis. In Rajshahi, significant rising trends were found in highest maximum post-monsoon temperature, lowest minimum monsoon temperature and highest maximum temperature from July to October, June and August for lowest minimum temperature. Falling trends were found in annual highest maximum and lowest minimum temperatures, pre-monsoon highest maximum temperature, lowest minimum winter temperature and January lowest minimum temperature. For Chittagong, significant increasing trends found in post-monsoon highest maximum temperature, June to December highest maximum temperature except July and December lowest minimum temperature. No significant decreasing trend was found in Chittagong.DOI: http://dx.doi.org/10.3329/jesnr.v6i2.22101 J. Environ. Sci. & Natural Resources, 6(2): 83-88 2013
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Lemaire, J. F., et K. Stegen. « Improved Determination of the Location of the Temperature Maximum in the Corona ». Solar Physics 291, no 12 (21 octobre 2016) : 3659–83. http://dx.doi.org/10.1007/s11207-016-1001-3.
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Dimri, A. P., et U. C. Mohanty. « Location-specific prediction of maximum and minimum temperature over the western Himalayas ». Meteorological Applications 14, no 1 (2007) : 79–93. http://dx.doi.org/10.1002/met.8.
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Serrano-Notivoli, Roberto, Santiago Beguería et Martín de Luis. « STEAD : a high-resolution daily gridded temperature dataset for Spain ». Earth System Science Data 11, no 3 (7 août 2019) : 1171–88. http://dx.doi.org/10.5194/essd-11-1171-2019.
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Abstract. Using 5520 observatories covering the whole territory of Spain (about 1 station per 90 km2 considering the whole period), a daily gridded maximum and minimum temperature was built covering a period from 1901 to 2014 in peninsular Spain and 1971 to 2014 in the Balearic and Canary Islands. A comprehensive quality control was applied to the original data, and the gaps were filled on each day and location independently. Using the filled data series, a grid of 5 km × 5 km spatial resolution was created by estimating daily temperatures and their corresponding uncertainties at each grid point. Four daily temperature indices were calculated to describe the spatial distribution of absolute maximum and minimum temperature, number of frost days and number of summer days in Spain. The southern plateau showed the maximum values of maximum absolute temperature and summer days, while the minimum absolute temperature and frost days reached their maximums at the northern plateau. The use of all the available information, the complete quality control and the high spatial resolution of the grid allowed for an accurate estimate of temperature that represents a precise spatial and temporal distribution of daily temperatures in Spain. The STEAD dataset is publicly available at https://doi.org/10.20350/digitalCSIC/8622 and can be cited as Serrano-Notivoli et al. (2019).
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Auld, Graeme, Gabriele C. Hegerl et Ioannis Papastathopoulos. « Changes in the distribution of annual maximum temperatures in Europe ». Advances in Statistical Climatology, Meteorology and Oceanography 9, no 1 (24 mai 2023) : 45–66. http://dx.doi.org/10.5194/ascmo-9-45-2023.
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Abstract. In this study we detect and quantify changes in the distribution of the annual maximum daily maximum temperature (TXx) in a large observation-based gridded data set of European daily temperature during the years 1950–2018. Several statistical models are considered, each of which analyses TXx using a generalized extreme-value (GEV) distribution with the GEV parameters varying smoothly over space. In contrast to several previous studies which fit independent GEV models at the grid-box level, our models pull information from neighbouring grid boxes for more efficient parameter estimation. The GEV location and scale parameters are allowed to vary in time using the log of atmospheric CO2 as a covariate. Changes are detected most strongly in the GEV location parameter, with the TXx distributions generally shifting towards hotter temperatures. Averaged across our spatial domain, the 100-year return level of TXx based on the 2018 climate is approximately 2 ∘C (95 % confidence interval of [2.03,2.12] ∘C) hotter than that based on the 1950 climate. Moreover, averaged across our spatial domain, the 100-year return level of TXx based on the 1950 climate corresponds approximately to a 6-year return level in the 2018 climate.
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Njok, Armstrong O., Effiong A. Archibong et Gertrude A. Fischer. « Diurnal Analysis of the Performance of Photovoltaic Systems under the Guinea Savannah Atmosphere in Ogoja, Cross Rivers State, Nigeria ». Physical Science International Journal 27, no 1 (15 janvier 2023) : 1–15. http://dx.doi.org/10.9734/psij/2023/v27i1767.
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A thorough experimental investigation was carried out to diurnally analyze the performance of photovoltaic systems deployed for domestic purposes under the guinea savannah atmosphere in Ogoja, Cross River State, Nigeria. In this study, the time of day to expect maximum efficiency from the photovoltaic (PV) module is shown, and the time of day that the panel temperature will exceed it maximum operating cell temperature is also shown. Instruments employed in the process include a digital solar power meter, digital hygrometer, digital infrared gun thermometer and a digital high precision photovoltaic panel maximum power point tracker (MPPT) to track and determine the maximum power, voltage and current produced by the photovoltaic module. The result shows that the highest level of efficiency was attained at 14:30 which reveals that the climatic condition which occurs at 14:30 is the most favorable for PV systems deployed for domestic purposes at the location. The study shows that 42% and 400C is the best relative humidity and PV temperature level for optimum PV efficiency at this location. In addition, the temperature of the study location appears encouraging as on average, the panel temperature will rarely exceed the maximum operating cell temperature for months besides January and march in which a cooling mechanism to regulate the panel temperature may be needed to avoid a massive loss in efficiency. An altitude of 85m above sea level makes the location relatively favorable for receiving intense solar radiation. With 90% efficiency assured, the location can be seen as suitable for generating electricity via PV technology and installing solar farms for commercial purposes.
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Cheng, Yung-Yun, Shang-Lien Lo, Chia-Chun Ho, Jen-Yang Lin et Shaw Yu. « Field Testing of Porous Pavement Performance on Runoff and Temperature Control in Taipei City ». Water 11, no 12 (13 décembre 2019) : 2635. http://dx.doi.org/10.3390/w11122635.
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The Taipei University of Technology, under contract from the Taipei City Government, completed a study on porous asphalt (PA) and permeable interlocking concrete brick (PICB) pavement performance with respect to stormwater runoff reduction and surface temperature mitigation. Additionally, the variation of infiltration rates against time of these pavements was monitored. The results show the following: (a) Runoff peak reduction ranged from 16% for large, intense storms to 55% for small, long-duration storms. Rainfall volume reduction ranged from 16% to 77% with an average of 37.6%; (b) Infiltration rate: for PICB, it decreased by 25% to 50% over a 15-month monitoring period, but the rate at one location increased significantly after cleaning; for PA, the rate remained high at one location, but decreased by 70%–80% after 10 months at two other locations, due mainly to clogging problems; (c) Surface temperature: during storm events, porous concrete bricks had on average lower temperatures compared to regular concrete with a maximum difference of 6.6 °C; for porous asphalt the maximum drop was 3.9 °C. During dry days, both PA and PICB showed a tendency of faster temperature increase as the air temperature rose, but also faster temperature decreases as the air cooled when compared to regular pavements. On very hot days, much lower surface temperatures were observed for porous pavements (for PA: 17.0 °C and for PICB: 14.3 °C) than those for regular pavements. The results suggest that large-scale applications of porous pavements could help mitigate urban heat island impacts.
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Dupuis, Debbie J. « A Model for Nighttime Minimum Temperatures ». Journal of Climate 27, no 19 (24 septembre 2014) : 7207–29. http://dx.doi.org/10.1175/jcli-d-14-00101.1.
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Abstract The southwestern United States has experienced some of the most important increases in nighttime minimum temperatures over the last 60 yr, and climate models are projecting more of the same to the end of the century. As climate, geography, and population density vary considerably over the area, very diverse extreme temperature levels and dynamics are observed. It is shown how nighttime minimum temperatures over the 1950–2009 period exhibit more complex dynamics than daytime maximum temperatures. The author studies nighttime minimum temperature series from 12 locations and presents one model capable of capturing all the features of the data at each location. The time series preprocessing model normalizes seasonal shocks by daily and yearly volatility components before modeling the residual volatility as an exponential generalized autoregressive conditional heteroskedasticity [EGARCH(1, 1)] process with seasonal autoregressive structure to account for the presence of nonlinear and seasonal linear dependence, respectively, in the residual series. An exceedance over high thresholds approach is then used to model the tail of the distribution of scaled residuals from the preprocessing model. The resulting marginal distribution of nighttime minimum temperature at each location is then examined to see how it has changed in mean, scale, and shape, respectively, over the 60-yr period. Changes at the 12 locations vary considerably: many locations have seen considerable change in some or all of the three parameters, while two locations have experienced little or no change.
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A. Kawi, Assmaa, Sana J.Yaseen et Rana L. « Finite Element Prediction of Temperature Rise Distribution in Turning Process of AISI 1045 Carbon Steel ». University of Thi-Qar Journal for Engineering Sciences 2, no 2 (1 juin 2011) : 52–69. http://dx.doi.org/10.31663/utjes.v2i2.194.
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In this paper the code DEFORM-3D V6.1 was used to perform a finite element analysis simulating the turning process of AISI 1045 carbon steel. A series of thermal simulations have been performed, the value and location of maximum temperature have been determined. The comparison of the simulations with earlier works gave promising trend for the presented work with a maximum percentage of error 3.23%. The results of this work show that the maximum temperature exists in the vicinity of the cutting edge. i.e. in the tool-chip contact and then starts cooling immediately when the tool crosses this region. Besides the maximum temperature in the tool-chip interface increases as the cutting time increases until the process reaches the steady-state condition where the temperature is alternating around the mean temperature. Finally the behavior of temperature differs in value and distribution for the same location and time (same boundary conditions) in the cutting direction with the change in depth of cut where the maximum temperature occurs at maximum depth of cut.
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Li, Jing, Shankar Mahalingam et David R. Weise. « Experimental investigation of fire propagation in single live shrubs ». International Journal of Wildland Fire 26, no 1 (2017) : 58. http://dx.doi.org/10.1071/wf16042.
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This work focuses broadly on individual, live shrubs and, more specifically, it examines bulk density in chaparral and its combined effects with wind and ignition location on the resulting fire behaviour. Empirical functions to predict bulk density as a function of height for 4-year-old chaparral were developed for two typical species of shrub fuels in southern California, USA, namely chamise (Adenostoma fasciculatum Hook & Arn.) and manzanita (Arctostaphylos spp. Adans.). Fuel beds of chamise foliage and small-diameter branches were burned in an open-topped wind tunnel. Three levels of bulk density, two ignition locations and two wind speeds were examined, focusing on overall fire behaviour. Mean maximum mass loss rate, elapsed time at which maximum mass loss rate occurred, flame height, flame angle, peak gas temperature and its peak change rate were measured. The mean maximum mass loss rate was not significantly affected by wind speed, ignition location, bulk density or moisture content. Both wind speed and ignition location significantly affected the time that maximum mass loss rate occurred. Only wind speed affected flame height and flame angle. The peak gas temperature within the shrub burning area was found to be mostly affected by the bulk density.
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Bono, Matthew, et Jun Ni. « The location of the maximum temperature on the cutting edges of a drill ». International Journal of Machine Tools and Manufacture 46, no 7-8 (juin 2006) : 901–7. http://dx.doi.org/10.1016/j.ijmachtools.2005.04.020.
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Oulmi, Kafia, Bariza Zitouni, Hocine Ben Moussa, Hafsia Abdenebi et G. M. Andreadis. « Total polarization effect on the location of maximum temperature value in planar SOFC ». International Journal of Hydrogen Energy 36, no 6 (mars 2011) : 4236–43. http://dx.doi.org/10.1016/j.ijhydene.2010.07.107.
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Wu, Guoxiong, Bian He, Yimin Liu, Qing Bao et Rongcai Ren. « Location and variation of the summertime upper-troposphere temperature maximum over South Asia ». Climate Dynamics 45, no 9-10 (3 mars 2015) : 2757–74. http://dx.doi.org/10.1007/s00382-015-2506-4.
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Shareef, Abbas Sahi. « Investigating the Effect of Cooling Air Passage on the Temperature Distribution in Turbine Blades ». Journal of Wasit for Science and Medicine 4, no 2 (8 novembre 2022) : 92–114. http://dx.doi.org/10.31185/jwsm.151.
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This paper was carried out to study the effect of the velocity ratio of cooling air on the temperature distribution in the turbine blade passage0The experimental and computation method gives a clear picture of the penetration area and the temperature distribution in the passage. All the calibration of the instrument and the laws of the five hole probe may be notes in the section test rig. Several cases have been studied in this research by using three-velocity ratio (VR=0.5, 1and 2), and three different locations (99% ,90% and 75%) from the end wall with the jets angle θ= 450.the hole diameter (d= 0.1 cm). The procedure solves the governing equation numerically by using the finite volume method semi implicit method for pressure-linked equation. Therefore the present results show an accepted agreement if compared with experimental work. The maximum temperature occurred of VR=0.5 and the jet location (99%) from the end wall .Therefore the temperatures are fluctuated at the core, and decreased gradually from the jet core to outside. The temperatures are increase with decrease the velocity ratio at the same the jut location from the axial chored.
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Kumar, Ravind, Mark Stephens et Tony Weir. « Temperature trends in Fiji : a clear signal of climate change ». South Pacific Journal of Natural and Applied Sciences 31, no 1 (2013) : 27. http://dx.doi.org/10.1071/sp13002.
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This paper analyses trends in temperature in Fiji, using data from more stations (10) and longer periods (52-78 years) than previous studies. All the stations analysed show a statistically significant trend in both maximum and minimum temperature, with increases ranging from 0.08 to 0.23°C per decade. More recent temperatures show a higher rate of increase, particularly in maximum temperature (0.18 to 0.69°C per decade from 1989 to 2008). This clear signal of climate change is consistent with that found in previous studies of temperatures in Fiji and other Pacific Islands. Trends in extreme values show an even stronger signal of climate change than that for mean temperatures. Our preliminary analysis of daily maxima at 6 stations indicates that for 4 of them (Suva, Labasa, Vunisea and Rotuma) there has been a tripling in the number of days per year with temperature >32°C between 1970 and 2008. The correlations between annual mean maximum (minimum) temperature and year are mostly strong: for about half the stations the correlation coefficient exceeds 60% over 50+ years. Trends do not vary systematically with location of station. At all 7 stations for which both trends are available there is no statistically significant difference between the trends in maximum and minimum temperatures.
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Basir, Hamed, Ayat Gharehghani, Abolfazl Ahmadi, Seyed Mostafa Agha Mirsalim et Marc A. Rosen. « Experimental and numerical investigation on the heat transfer of an automotive engine’s turbocharger ». Proceedings of the Institution of Mechanical Engineers, Part D : Journal of Automobile Engineering 235, no 8 (17 janvier 2021) : 2124–35. http://dx.doi.org/10.1177/0954407020987829.
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Measuring the temperature distribution in a complex and important engine part, such as a turbocharger, is essential for improving engine performance and efficiency. Heat transfer from the turbine to the compressor can strongly influence the turbocharger performance. One of the main measurement methods involves the installation of multiple K-type sensors. However, the location as well as the maximum and minimum temperatures of the turbocharger and the subsequent critical points may not be obtained by using sensors. In the current study, thermocouples, as well as an infra-red camera, are used to study the temperature distribution of the turbocharger housing in a spark ignition engine. A new method is introduced to determine the thermal radiation coefficient of the turbocharger housing by using a laboratory furnace and an infra-red camera. Together with experiments, the finite element method is used to find the temperature distribution in the turbocharger for all thicknesses. Comparing the temperature distribution obtained from simulation with experimental data, an acceptable level of agreement is observed. The location and temperature of the hottest area in experimental and numerical investigations are close to the waste gate. Temperatures using the finite element method for bearings exhibit maximum and minimum errors of 4.9% and 2.3%, respectively, indicating reasonable accuracy for the simulation.
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Shibib, Khalid, Mohammed Minshid et Nebras Alattar. « Thermal and stress analysis in Nd : YAG laser rod with different double end pumping methods ». Thermal Science 15, suppl. 2 (2011) : 399–407. http://dx.doi.org/10.2298/tsci101201004s.
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In this work, the finite element analysis has been used to predict the temperature distribution in Nd: YAG laser rod; double end-pumped by two methods Gaussian or top hat beam. The rod is cooled by water passing through annular, which surrounds the active media. The temperature distribution has been used to predict numerically, the nodal displacements, strain and stress based on the principle of virtual work. The main task is to determine the temperature distribution in Nd: YAG laser rod, the subsequent value and location of maximum tensile hoop stress associated with the two types of the double end pumping for different absorption power. Some conclusions are obtained; as the radius pumping ratio increases the location of maximum hoop stress will move toward the periphery and vice-versa. Small reduction is observed in the location of maximum hoop stress when pumping method change from the top-hat beam to Gaussian beam, especially at low radius pumping ratio and high absorption power. Top hat beam end pumping will cause more intense tension hoop stress at the facets of the rod than that of Gaussian beam even the later may produce high center temperature. This work may be important for designer while choosing the type of pumping, maximum produced tensile hoop stress and its location, especially when hoop stress is ultimate.
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BHOWMIK, S. K. ROY, SANKAR NATH, A. K. MITRA et H. R. HATWAR. « Application of Neural Network Technique to improve the location specific forecast of temperature over Delhi from MM5 model ». MAUSAM 60, no 1 (27 novembre 2021) : 11–24. http://dx.doi.org/10.54302/mausam.v60i1.958.
Texte intégralRésumé :
India Meteorological Department (IMD) has been using direct model output (2 meters height temperature) of MM5 model as numerical guidance for forecasting maximum and minimum temperature of Delhi in short range time scale (up to 72 hours). Performance statistics of the direct model outputs of the model for maximum and minimum temperature show that forecast skill of the model is reasonably good, particularly for the minimum temperature. For further improving the model forecast, Neural Network (NN) as well as regression techniques are applied so that the systematic errors of the direct model output of the model for maximum and minimum temperature could be reduced. The study shows that both Neural Network approach and regression technique are capable to improve the forecast skill of maximum and minimum temperature. Daily modified forecasts are found persistently closer to the observations when the method is tested with the independent sample. The methods are found to be promising for operational application.
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Al-Saadi, Luma M., et Sundus H. Jaber. « Relationship of Surface Temperature and Average Relative Humidity for Selected Governorates of Iraq ( Baghdad, Al-Mosul and Al-Muthna ) ». IOP Conference Series : Earth and Environmental Science 1223, no 1 (1 août 2023) : 012016. http://dx.doi.org/10.1088/1755-1315/1223/1/012016.
Texte intégralRésumé :
Abstract study and analysis the trends of the paths of the climatic elements (maximum and minimum temperatures and relative humidity) received great attention and evaluated their statistical importance in terms of assessing climate changes. In this research, data were taken for the maximum and minimum temperature and relative humidity for several different governorates in terms of location, namely (Baghdad, al-Al-Mosul and Al-Muthna), and the Sigma plot program was used to extract the different forms of the relationship between the maximum and minimum temperature and the average relative humidity for each month of the selected years in this study. The time series of temperature and relative humidity showed that the relationship between them is an inverse relationship, as well as the fluctuations that occur in the values of temperature and relative humidity between high and low in different months of the year, but clearly appeared in the spring and autumn seasons, and the reason for this is that these two seasons have transitional characteristics weather, especially temperature. Also, through the values of the correlation coefficient that was extracted for all months, and its results were mostly negative, which are mentioned in the attached tables, which indicate the inverse relationship between of them the two elements mentioned above. through the data and forms that have been reached and the observation of the difference in values between the governorates, starting from Mosul with low temperatures and high relative humidity, and down to Baghdad and then Al-Muthna, which begins with an increase in temperatures and a decrease in relative humidity, and this explains the importance of the geographical location of each governorate and the extent of its impact on the values of temperatures. Temperature, relative humidity and other climatic elements.
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Mendez, Patricio F. « Calculation of thermal features in welding and additive manufacturing ». IOP Conference Series : Materials Science and Engineering 1281, no 1 (1 mai 2023) : 012021. http://dx.doi.org/10.1088/1757-899x/1281/1/012021.
Texte intégralRésumé :
Abstract This paper summarizes multiple engineering expressions that enable the prediction of thermal magnitudes of interest associated with moving heat sources. The expressions use only fundamental parameters available before performing any experiments, and their calculation is algebraic, without the need for numerical methods. All expressions are based on the fundamental governing equations of heat transfer in the solid. The magnitudes predicted include maximum width and its location, maximum penetration, thickness of HAZ, maximum temperature and its location, leading and trailing edge of an isotherm, heating and cooling rate, aspect ratio of an isotherm, melting efficiency, cooling time from 800°C to 500°C, solidification time, and maximum distribution of a heat source to reach a target temperature. Parameters involved include heat source power and speed, thermal conductivity and diffusivity of the substrate material, temperature of interest and preheat or interpass temperature. Temperature-dependent properties are accounted for by the use of effective properties. The expressions proposed can be extended into sophisticated geometries for welding and specific additive manufacturing cases.
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LALAROY, SUKUMAR, SANJIB BANDYOPADHYAY et SWETA DAS. « Prediction of maximum or minimum air temperature in a coastal location in West Bengal ». MAUSAM 64, no 4 (20 décembre 2021) : 671–80. http://dx.doi.org/10.54302/mausam.v64i4.750.
Texte intégralRésumé :
bl 'kks/k i= dk mÌs'; Hkkjrh; rVh; LFkku vFkkZr~ if'peh caxky ds vyhiqj ¼dksydkrk½ esa izsf{kr HkweaMyh; lkSj fofdj.k dh enn ls gjxzhCl fofdj.k QkWewZyk ls rkjh[kokj la'kksf/kr KRS irk djuk gS ftlls fd vkxs ;fn U;wure rkieku ¼Tmin½ Kkr gks rks vf/kdre rkieku ¼Tmax½ dk iwokZuqeku nsus esa vFkok blds foijhr] mi;ksx fd;k tk ldsA HkweaMyh; lkSj fofdj.k ds chp lglaca/k dh x.kuk rkjh[kokj fd, x, /kwi ds ?kaVkokj vk¡dM+ksa ds vkSlr ds mi;ksx ftlesa vkaXLVªkse izsLdkWV QkewZyk ls izkIr fu;rkad as = 0-25 vkSj bs = 0-5 gS] ls dh xbZZ gSA blesa izsf{kr fd, x, HkweaMyh; lkSj fofdj.k vkadM+ksa dk v/;;u fd;k x;k gSA ;g fuf'pr :i ls dgk tkrk gS fd vkaxLVªkse izsldkWV QkewZyk HkweaMyh; lkSj fofdj.k dk lVhd vkdyu djrk gS vkSj ;g lgh ik;k tkrk gSA bl 'kks/k i= esa gjxzhCl fofdj.k QkewZyk ¼ftles KRS = 0-19 fy;k x;k gS½ ls rkjh[kokj izkIr fd, x, vf/kdre rkiekuksa rFkk U;wure rkiekuksa ds vkSlr ¼vkadM+s Hkkjr ekSle foKku foHkkx ds vyhiqj] dksydkrk ftyk & 24 ijxuk ds dk;kZy; ls izkIr½ dk mi;ksx djds HkweaMyh; lkSj fofdj.k ds chp lglaca/k dh x.kuk dh xbZ gS vkSj bldk v/;;u izsf{kr HkweaMyh; lkSj fofdj.k ds lkFk Hkh fd;k x;k gSA rkjh[kokj la'kksf/kr KRS dh x.kuk gjxzhCl fofdj.k QkewZyk ls dh xbZA blesa HkweaMyh; lkSj fofdj.k ds izsf{kr vkadM+ksa] rkjh[kokj vf/kdre rkiekuksa vkSj U;wure rkiekuksa ds vkSlr mi;ksx esa fy, x, gSaA bls fdlh LVs'ku ds vf/kdre rkiekuksa vkSj U;wure rkieku vkadMksa ds rkjh[kokj KRS ds mi;ksx ds }kjk vkl ikl ds {ks=ksa ds ok"iksRltZu ds fy, HkweaMyh; lkSj fofdj.k dk vkdyu djus ds fy, Hkh mi;ksx esa yk;k tk ldrk gSA
The objective of this study is to find the date wise corrected KRS from the Hargreaves Radiation formula with the help of observed global solar radiation for the Indian coastal location namely Alipore (Kolkata) in West Bengal so that subsequently it can be used for predicting maximum temperature Tmax if minimum temperature Tmin is known or vice-versa. The correlation between the global solar radiation calculated by using date wise average sunshine hour data with constants as = 0.25 and bs = 0.5, from Angstrom Prescott formula with the observed global solar radiation data was studied. The assertion that the Angstrom Prescott formula gives nearly accurate estimation of global solar radiation has been found to be correct. Correlation between the global solar radiation calculated by using date wise average of Tmax and Tmin (sourced from IMD located at Alipore, Kolkata, District - South 24 parganas) from Hargreaves Radiation formula (taking KRS = 0.19 ) with the observed global solar radiation data was also studied. Date wise corrected KRS by Hargreaves Radiation formula was computed using the observed data of global solar radiation, date wise average of maximum temperature Tmax and minimum temperature Tmin. The date wise corrected KRS can be used for better prediction of Tmax and Tmin. Also it can be used for estimation of global solar radiation for reference evapo-transpiration of the neighbourhood areas by utilizing the date wise KRS with the Tmax and Tmin of the station.
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Cong, Wei, Long Shi, Zhicheng Shi, Min Peng, Hui Yang, Shaogang Zhang et Xudong Cheng. « Effect of train fire location on maximum smoke temperature beneath the subway tunnel ceiling ». Tunnelling and Underground Space Technology 97 (mars 2020) : 103282. http://dx.doi.org/10.1016/j.tust.2020.103282.
Texte intégral
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Kumara PGA, Lakshman, Tonette Laude, Jose Hernandez, Pearl Sanchez, Moises Dorado, Jose Nestor Garcia, Gerardo Gauna et Pompe Sta Cruz. « Climatic Factors Affecting Maize Grain Yield in Different Growing Areas of the Philippines ». Philippine Agricultural Scientist 104, no 4 (1 décembre 2021) : 351–62. https://doi.org/10.62550/hf26100021.
Texte intégralRésumé :
Seasonal climate variation is one of the problems faced by Filipino maize farmers, due to varying climatic elements such as solar radiation, rainfall, relative humidity, and air temperature. This study determined the seasonal productivity of selected maize varieties in the major growing areas in the Philippines, and identified the yield-limiting climatic factors specific to location and growing season. Grain yield, covering two wet and dry seasons (2016-2018) from seven field trials (representing 3 climatic types) of the National Corn Testing (NCT) were used in the study. Climatic data (2016-2018) were gathered from the PAGASA weather station nearest to the trial site. Significant variation in the monthly solar radiation, rainfall, relative humidity, and the mean temperature (309.1-786.6 MJ m-2, 19.9-667.5 mm, 64.3-91.4%, 18.8-35.8°C, respectively) were observed across seven locations. Relative humidity significantly varied by season. Mean temperatures below 30°C and mean relative humidity of more than 80% were observed across locations. Grain yield variations due to season (3394.8-9985.1 kg ha-1), location (1382.4-11931.4 kg ha-1), and climate type (3052.1-8650.9 kg ha-1) were highly significant. Grain yield was significantly affected by cumulative solar radiation specific to variety and season. Solar radiation use efficiency (SRUE) during wet season was highly variable, and consistently higher SRUE was observed during dry season. Grain yield of the three varieties were correlated with growing degree days (GDD) during wet and dry seasons (r = 0.28, 0.29, and 0.33). The grain yield of 30B80 was more affected by cumulative solar radiation (r = 0.46), while USM Var10 (r = 0.33) was more associated with GDD. Solar radiation and minimum temperature positively affect the grain yield of variety 30B80, while maximum temperature and relative humidity had negative effect. Solar radiation was the major yield-limiting factor for variety 30B80, whereas maximum temperature and solar radiation increased the grain yield of IPB Var11. The major yield-limiting factor for IPB Var11 was relative humidity. Grain yield of USM Var10 increased with solar radiation, while relative humidity and maximum temperature had negative effect. Location was the maize yield-limiting factor, whereas relative humidity affected the grain yield of USM Var10 dominantly. Significant seasonal climate variation can be observed in the major maize growing areas resulting in different seasonal productivity, while solar radiation and relative humidity are the major yield-limiting climatic factors. Moreover, the hybrid variety, 30B80, can be recommended for dry season in Batac, Tupi, and Baybay; wet season in Ubay; and both wet and dry season in Maramag, Kabacan, and Ilagan as a high-yielding maize variety.
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Anderson, David, Andrew Warkentin et Robert Bauer. « EFFECT OF FACE COOLING ON WORKPIECE TEMPERATURES USING 2D AND 3D FINITE ELEMENT ANALYSIS OF CREEP-FEED GRINDING ». Transactions of the Canadian Society for Mechanical Engineering 32, no 3-4 (septembre 2008) : 439–52. http://dx.doi.org/10.1139/tcsme-2008-0029.
Texte intégralRésumé :
This work uses validated 2D and 3D finite element models of the creep-feed grinding operation to study the effects of face cooling on the workpiece temperatures. The results show that as the intensity of the face cooling is increased the maximum contact temperature decreases and the location of the maximum contact temperature shifts away from the finished workpiece material and towards the uncut workpiece surface. The finite element models are also used to study the maximum temperatures along the workpiece during a complete grinding pass. The temperature profiles show that there are four important temperature features on the workpiece, which are the cut-in, steady-state, temperature spike, and cut-out zones. Cut-in occurs when the grinding wheel initially engages the workpiece, steady-state occurs in the middle of the workpiece, the temperature spike occurs at the beginning of cut-out, and cut-out occurs as the grinding wheel disengages from the workpiece. Finally, the results show that face cooling need only be applied to the area immediately adjacent to the contact zone to be effective and that there is very little benefit to applying coolant to the entire front and back workpiece faces.
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Swanson, David K., Barbara Lacelle et Charles Tarnocai. « Temperature and the boreal-subarctic maximum in soil organic carbon ». Géographie physique et Quaternaire 54, no 2 (2 octobre 2002) : 157–67. http://dx.doi.org/10.7202/004874ar.
Texte intégralRésumé :
AbstractOn the plains of central North America and western Siberia, soil carbon storage and cover by organic soils are highest in the region with mean annual soil temperatures near 0° C, and generally decrease to the north and south. The location of this large soil carbon sink in the boreal and subarctic is probably due in part to the low heat availability in the soil as compared to the air in these regions. The thermal advantage of the air environment gives green plants a metabolic advantage over decomposers in the soil, which favors soil carbon accumulation. The thermal advantage of the air environment relative to the soil is greatest where mean annual soil temperatures are near or a few degrees below the lower limit of biological activity for cold-adapted soil organisms and plants, i.e. near 0° C.
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Sinha, Amartya, et Aditya Kumar Jha. « Variation in coefficient of permeability of soil with the variation of temperature at prominent locations in India throughout a year ». Journal of Engineering Research and Application 01, no 02 (2022) : 01–11. http://dx.doi.org/10.55953/jera.2022.2101.
Texte intégralRésumé :
Permeability is a significant property of soil. The coefficient of permeability influences the seepage of water through soil. This coefficient of permeability further depends on the viscosity of water, average particle size, and void ratio of the soil present at the location. Variation of these factors results in the variation of the coefficient of permeability which results in the seepage of water through the earthen structures like earthen dams. In hydraulic structures, seepage of water is one of the major cause for piping failure. This study aims to numerically establish the trend of variation of the coefficient of permeability with the variation of viscosity of water which is caused due to changes in temperature at various prominent locations in India. The locations selected are Delhi, Mumbai, Chennai, Kolkata, Jaipur, and Srinagar. These locations are selected to cover each type of geographical condition, climatic condition (mild and extreme), temperature range, and soil type. The ratio between maximum value of coefficient of permeablity to the minimum value of the same was calculated for each location. It was observed that among the chosen locations, Jaipur showed the maximum variation of permeability while Chennai had the minimum variation. The comparison established may provide an additional source of data for the efficient design of hydraulic structures to be constructed near the selected locations.
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V. M. SANDEEP, V. U. M. RAO, B. BAPUJI RAO, V. P. PRAMOD, P. SANTHIBHUSHAN CHOWDARY, P. VIJAYA KUMAR, G. BHARATHI, N.R. PATEL et P.MUKESH. « Impact of climate change on sorghum productivity in India and its adaptation strategies ». Journal of Agrometeorology 20, no 2 (1 juin 2018) : 89–96. http://dx.doi.org/10.54386/jam.v20i2.517.
Texte intégralRésumé :
Future climate change projections for India indicate distinct rise in temperature and increased variability in rainfall. This study aims to assess the impact of climate change on sorghum productivity in India in future climatic periods (2025, 2050 and 2075) using DSSAT-sorghum and suggest adaptation strategies to negate the negative impact of climate change on sorghum productivity in the future climates. Three CMIP-5 climate models (GFDL-ESM2M, MIROC5 and NorESM1-M) generated weather data for three future periods were used at various locations for kharif (Akola, Dharwad, Surat and Udaipur) and rabi (Bijapur, Dharwad, Rahuri and Solapur) seasons to simulate sorghum yields. Projected changes in day-night temperatures and rainfall during kharif and rabi growing seasons at these locations are diverse both in direction and magnitude. Increasing trend in rainfall is observed during both crop seasons towards the end of 21st century. Sorghum crop is likely to experience warmer temperature in the second half of the century and rise in minimum temperature is more explicit than maximum temperature at all the locations. Location specific management options can be adopted to mitigate the negative impacts of the change in climate in future projected scenarios, as they are found beneficial.
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Chen, Jian, Jianzhong Li et Li Yuan. « Effects of Inlet Pressure on Ignition of Spray Combustion ». International Journal of Aerospace Engineering 2018 (2018) : 1–13. http://dx.doi.org/10.1155/2018/3847264.
Texte intégralRésumé :
To evaluate the effects of inlet pressure on the ignition process of spray combustion, the images of the ignition process were recorded and the outlet temperatures were measured under inlet pressure of 0.04–0.16 MPa. The initial flame formation and flame propagation and the effects of the inlet pressure on the initial flame formation were observed. A variation of outlet temperature, flame propagation, initial time of outlet temperature rise, time of maximum temperature rise, and temperature rise rate was investigated. With increasing inlet pressure, the time of initial flame formation and time of maximum area growth rate of flame decrease and the centroid location move radially. The radial distances of the initial flame centroid gradually increased by about 13%, 5%, 6%, 12%, 57%, and 24%. The trace of flame centroid is determined from the distribution of fuel and is related to the initial SMD of the atomizer. The maximum temperature rise and temperature rise rate are determined by the rate of flame chemical reaction, rate of large drop evaporation, and fuel/air ratio. With increasing inlet pressure, the maximum temperature rise increased by 50%, 58%, 12%, 11%, and −9%, respectively. Meanwhile, the rate of the temperature rise increased by about 47%, 54%, 11%, 11%, and −7%, respectively.
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Mohsen Jweeg, Emad Qasem Hussein, Farhan Lafta Rashid et Ali Basem. « Investigation of Two-Way Fluid-Structure Interaction of Blood Flow at Different Temperature using CFD ». Journal of Advanced Research in Applied Sciences and Engineering Technology 36, no 2 (30 décembre 2023) : 120–30. http://dx.doi.org/10.37934/araset.36.2.120130.
Texte intégralRésumé :
At this work, fluid-structure interaction was used to biomechanical challenges relating to blood flow in artery bifurcation to investigate potential solutions. The purpose of this study was to evaluate the influence that artery geometry has under constant flow, pulsatile flow, and varied blood temperatures. In this study, the flow of blood through the artery was simulated using a non-Newtonian fluid model, and the finite element technique was utilized to analyse the data. For the purpose of analysing the differences between pulsatile flow and steady flow, a user-defined function, or UDF, was developed as part of the suggested input velocity model. In order to accurately estimate the pressure distribution, velocity flow, wall shear stress, and wall deformation, a simulation called ANSYS 17.2 is used to model the fluid-structure interaction that occurs when blood flow is superimposed on an arterial wall. According to the findings, the pressure amplitude steadily increases in the artery zone for high temperatures, demonstrating that the projected pressure is 15% greater than it was when the temperature was low. This is in contrast to the low temperature, for which the predicted pressure was 15% lower. In addition, the area close to the apex has the highest levels of shear stress, which then drop down precipitously farther along the wall until they reach an almost constant level. In general, the location of maximum total deformation is shown at peak systole for the artery when the temperature is high. This is the location where the pressure is high, particularly at the artery bifurcation, and where there is a maximum wall deformation of 0.447 mm. In addition, this is the location where the maximum total deformation occurs. These findings are of great use in the design of arterial bifurcation as well as the assessment of recurrent mechanical loads, both of which contribute to the prediction of life.
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Kweon, Ohsang, Heungyoul Kim et Hyun Kang. « Investigating the Impact of Opening Size on Fire Spread Across Vertical Exterior Surfaces ». Journal of the Korean Society of Hazard Mitigation 23, no 4 (31 août 2023) : 71–77. http://dx.doi.org/10.9798/kosham.2023.23.4.71.
Texte intégralRésumé :
This study examined the risk of vertical fire spread on exterior walls subjected to flame ejection by measuring temperature and heat flux during real-scale fire experiments. The fire experiment was conducted in a mock-up measuring 2.4(L) × 3.6(W) × 2.4(H) m. Wood cribs were used as the combustible material, and heptane as the initial ignition source. The mock-up featured two singular openings of different dimensions, 2.2(L) × 2.0(H) m (#1) and 2.2(L) × 1.0(H) m (#2), on its front side. Temperature and heat flux variations were measured at the upper part (0.0 m) and on the exterior upper wall (0.5 and 1.0 m) of the mock-up. The maximum heat flux was 15.0 kW/m<sup>2</sup> at location #1 and 42.4 kW/m<sup>2</sup> at location #2. The maximum temperature was 291.0 ℃ at location #1 and 626.4 ℃ at location #2. This study examined the burning rate of the compartment and the impact of the opening size on the radiant heat and temperature of the exterior walls.
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Zhang, Yu Xiang, Cong Fu Fang, Guo Qin Huang, Yi Qing Yu et Xi Peng Xu. « Analysis of Temperatures in Sawing of Granite Based on Parabolic Heat Distribution ». Key Engineering Materials 589-590 (octobre 2013) : 184–87. http://dx.doi.org/10.4028/www.scientific.net/kem.589-590.184.
Texte intégralRésumé :
A temperature model was advanced based on a parabolic heat flux distribution in sawing contact zone in the present paper. It is found that the maximum temperature for parabolic distribution is more higher than that for triangular distribution in the sawing contact zone, and the location point of the maximum temperature for parabolic distribution in the sawing contact zone is much nearer the entrance than that for triangular distribution.
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Perry, Katharine B., et Todd C. Wehner. « A Heat Unit Accumulation Method for Predicting Cucumber Harvest Date ». HortTechnology 6, no 1 (janvier 1996) : 27–30. http://dx.doi.org/10.21273/horttech.6.1.27.
Texte intégralRésumé :
The use of a previously developed model for predicting harvest date in cucumber production systems is described. In previous research we developed a new method using daily maximum temperatures in heat units to predict cucumber harvest dates. This method sums, from planting to harvest, the daily maximum minus a base temperature of 60F (15.5 C), but if the maximum is >90F (32C) it is replaced by 90F minus the difference between the maximum and 90F. This method was more accurate than counting days to harvest in predicting cucumber harvest in North Carolina, even when harvest was predicted using 5 years of experience for a particular location and planting date.
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O. Akpootu, Davidson, Bello I. Tijjani et Usman M. Gana. « New temperature dependent models for estimating global solar radiation across the midland climatic zone of Nigeria ». International Journal of Physical Research 7, no 2 (22 juillet 2019) : 70. http://dx.doi.org/10.14419/ijpr.v7i2.29214.
Texte intégralRésumé :
Authentic information of the availability of global solar radiation is significant to agro/hydro meteorologists, atmospheric Physicists and solar energy engineers for the purpose of local and international marketing, designs and manufacturing of solar equipment. In this study, five new proposed temperature dependent models were evaluated using measured monthly average daily global solar radiation, maximum and minimum temperature meteorological data during the period of thirty one years (1980-2010). The new models were compared with three existing temperature dependent models (Chen et al., Hargreaves and Samani and Garcia) using seven different statistical validation indicators of coefficient of determination (R2), Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE), t – test, Nash – Sutcliffe Equation (NSE) and Index of Agreement (IA) to ascertain the suitability of global solar radiation estimation in five different locations (Zaria, Bauchi, Jos, Minna and Yola) situated in the Midland climatic zone of Nigeria. In each location, the result shows that a new empirical regression model was found more accurate when compared to the existing models and are therefore recommended for estimating global solar radiation in the location and regions with similar climatic information where only temperature data are available. The evaluated existing Hargreaves and Samani and Garcia temperature based models for Jos were compared to those available in literature and was found more suitable for estimating global solar radiation for the location. The comparison between the measured and estimated temperature dependent models depicts slight overestimation and underestimation in some months with good fitting in the studied locations. However, the recommended models give the best fitting.
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Teasdale, John R., et Aref A. Abdul-Baki. « Soil Temperature and Tomato Root Growth Under Black Polyethylene and Hairy Vetch Mulches ». HortScience 30, no 4 (juillet 1995) : 850B—850. http://dx.doi.org/10.21273/hortsci.30.4.850b.
Texte intégralRésumé :
Temperature and root length at selected locations within a raised bed under black polyethylene (BP), hairy vetch (Vicia villosa Roth) residue (HV), or bare soil (BS) were measured and correlated with tomato (Lycopersicon esculentum Mill.) growth. Early in the season, before the tomato leaf canopy closed, soil temperature was influenced more by vertical depth in the bed than by horizontal location across the bed. Maximum soil temperatures under BP averaged 5.7 and 3.4C greater than those under HV at 5- and 15-cm depths, respectively. More hours at temperatures >20C during the first 4 weeks probably accounted for greater early root and shoot growth and greater early yield of tomatoes grown in BP rater than in HV or BS. After canopy closure, soil temperatures under tomato foliage were reduced compared to those on the outer edge of the beds. Most tomato roots were in areas of the bed covered by the tomato canopy where temperatures in all treatments remained in the optimum 20 to 30C range almost continuously. Soil temperature, therefore, did not explain why total yield was higher in the HV than the BP or BS treatments.
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Guo, Z., D. L. Rhode et F. M. Davis. « Computed Eccentricity Effects on Turbine Rim Seals at Engine Conditions With a Mainstream ». Journal of Turbomachinery 118, no 1 (1 janvier 1996) : 143–52. http://dx.doi.org/10.1115/1.2836595.
Texte intégralRésumé :
A previously verified axisymmetric Navier–Stokes computer code was extended for three-dimensional computation of eccentric rim seals of almost any configuration. All compressibility and thermal/momentum interaction effects are completely included, and the temperature, pressure, and Reynolds number of the mainstream, coolant stream, and turbine wheel are fixed at actual engine conditions. Regardless of the seal eccentricity, both ingress and egress are found between θ = −30 and 100 deg, which encompasses the location of maximum radial clearance at θ = 0 deg. All other θ locations within the rim seal show only egress, as does the concentric base case for all circumferential locations. Further, the maximum ingress occurs near θ = 30 deg for all eccentricities. This is found to produce a blade root/retainer temperature rise from the concentric case of 390 percent at 50 percent eccentricity and a 77 percent rise at 7.5 percent eccentricity. In addition, the nature of an increased eccentricity causing a decreased seal effectiveness is examined, along with the corresponding increase of cavity-averaged temperature.
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Mitsui, Junichi, Yukio Hori et Masato Tanaka. « An Experimental Investigation on the Temperature Distribution in Circular Journal Bearings ». Journal of Tribology 108, no 4 (1 octobre 1986) : 621–26. http://dx.doi.org/10.1115/1.3261285.
Texte intégralRésumé :
The temperature distributions in full circular bearings were measured in a test rig. The effects of journal speed, lubricant viscosity, and clearance ratio on the maximum bearing temperature and its location were discussed. The results were compared with the theoretical analysis by the present authors and good agreement was obtained over the wide range of operating conditions. The maximum bearing temperature is found to increase considerably with the increase of speed or lubricant viscosity and also with the decrease of clearance ratio. Its angular position is found to vary with speed and clearance ratio. These phenomena can be explained by the characteristics of maximum film temperature in the oil film.
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Baek, B. J., B. F. Armaly et T. S. Chen. « Measurements in Buoyancy-Assisting Separated Flow Behind a Vertical Backward-Facing Step ». Journal of Heat Transfer 115, no 2 (1 mai 1993) : 403–8. http://dx.doi.org/10.1115/1.2910692.
Texte intégralRésumé :
Measurements of velocity and temperature distributions in buoyancy-assisting laminar mixed convection boundary-layer flow over a vertical, two-dimensional backward-facing step are reported. The leading surface upstream of the step and the step itself were adiabatic, and the surface downstream of the step was heated and maintained at a uniform temperature. A laser-Doppler velocimeter and a cold-wire anemometer were utilized to measure simultaneously the velocity and the temperature distributions in the recirculation and the reattached region downstream of the step. Flow visualization was used to study the flow and to measure the reattachment length for different free-stream velocities (0.37 m/s ≤ u0 ≤ 0.72 m/s), wall temperature differences (10°C ≤ ΔT ≤ 30°C), and step heights (0.38 cm ≤ s ≤ 1 cm). Results show that for a given step height the reattachment length decreases as the buoyancy force parameter, Grs/Res2, increases. The Nusselt number at the heated wall downstream of the step increases and the location of its maximum value moves closer to the step as the buoyancy force parameter increases. For the present experimental range, it is found that the location of the maximum Nusselt number occurs downstream of the reattachment point and the distance between the reattachment point and the location of the maximum Nusselt number increases as the buoyancy force parameter increases. Predicted behavior agrees favorably with the measured results.
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KUMAR, VISHNU, SUDHEER KUMAR, S. P. SINGH, S. S. VAISH, DEEPSHIKHA DEEPSHIKHA, J. B. KHAN, A. S. KHARUB et G. P. SINGH. « Identification of resistant genotypes and representative environments for spot blotch (Biploris sorokiniana) in barley (Hordeum vulgare) ». Indian Journal of Agricultural Sciences 90, no 5 (4 septembre 2020) : 909–13. http://dx.doi.org/10.56093/ijas.v90i5.104358.
Texte intégralRésumé :
A set of 31 barley genotypes was evaluated at four locations, viz. Kanpur, Pantnagar, Varanasi and Faizabad for two years (2016 and 2017) against spot blotch [Biploris sorokiniana (Sacc.) Shoem.] resistance. The combined analysis of variance revealed significant influence of year (5.64%) and location (18.08%) effects with significant genotypic effects (29.05%). Location-wise, the highest susceptibility was observed at Varanasi (51.61%) followed by Kanpur (19.35%) whereas, the moderately susceptible reactions were obtained at Faizabad (67.74 %) and Kanpur (61.29%) locations. In heritability adjusted GGE biplot analysis, the ratio of (G+G × E)/(E+G+G × E) was estimated as 71.77 % and substantiated usefulness of generated biplots to elucidate resistant and stable genotypes with location discrimination. In AMMI analysis, the initial two principal components (PCs) cumulatively explained 90.7 % of total variation with individual scores of 51.8 % and 38.9 %, respectively. The triangular image of the initial three PCs depicted scattered pattern for disease reaction and varied response for the locations. The weather parameters, viz. maximum temperature, minimum temperature and sunshine hr/day showed strong correlations 0.87**, 0.83** and 0.64* with spot blotch severity. The genotypes, DWRB 180, PL 891 and DWRB 190 were found promising and suggested to be used in future resistance breeding and spot blotch genetic studies. The locations Varanasi and Faizabad were found type 2 discriminative and representative environments for spot blotch.
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Kruel, Izabele B., Monica C. Meschiatti, Gabriel C. Blain et Ana M. H. de Ávila. « Climate trends in the municipality of Pelotas, state of Rio Grande do Sul, Brazil ». Engenharia Agrícola 35, no 4 (août 2015) : 769–77. http://dx.doi.org/10.1590/1809-4430-eng.agric.v35n4p769-777/2015.
Texte intégralRésumé :
ABSTRACT Changes in the frequency of occurrence of extreme weather events have been pointed out as a likely impact of global warming. In this context, this study aimed to detect climate change in series of extreme minimum and maximum air temperature of Pelotas, State of Rio Grande do Sul, (1896 - 2011) and its influence on the probability of occurrence of these variables. We used the general extreme value distribution (GEV) in its stationary and non-stationary forms. In the latter case, GEV parameters are variable over time. On the basis of goodness-of-fit tests and of the maximum likelihood method, the GEV model in which the location parameter increases over time presents the best fit of the daily minimum air temperature series. Such result describes a significant increase in the mean values of this variable, which indicates a potential reduction in the frequency of frosts. The daily maximum air temperature series is also described by a non-stationary model, whose location parameter decreases over time, and the scale parameter related to sample variance rises between the beginning and end of the series. This result indicates a drop in the mean of daily maximum air temperature values and increased dispersion of the sample data.
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Hurter, F., et O. Maier. « Tropospheric profiles of wet refractivity and humidity from the combination of remote sensing data sets and measurements on the ground ». Atmospheric Measurement Techniques 6, no 11 (14 novembre 2013) : 3083–98. http://dx.doi.org/10.5194/amt-6-3083-2013.
Texte intégralRésumé :
Abstract. We reconstruct atmospheric wet refractivity profiles for the western part of Switzerland with a least-squares collocation approach from data sets of (a) zenith path delays that are a byproduct of the GPS (global positioning system) processing, (b) ground meteorological measurements, (c) wet refractivity profiles from radio occultations whose tangent points lie within the study area, and (d) radiosonde measurements. Wet refractivity is a parameter partly describing the propagation of electromagnetic waves and depends on the atmospheric parameters temperature and water vapour pressure. In addition, we have measurements of a lower V-band microwave radiometer at Payerne. It delivers temperature profiles at high temporal resolution, especially in the range from ground to 3000 m a.g.l., though vertical information content decreases with height. The temperature profiles together with the collocated wet refractivity profiles provide near-continuous dew point temperature or relative humidity profiles at Payerne for the study period from 2009 to 2011. In the validation of the humidity profiles, we adopt a two-step procedure. We first investigate the reconstruction quality of the wet refractivity profiles at the location of Payerne by comparing them to wet refractivity profiles computed from radiosonde profiles available for that location. We also assess the individual contributions of the data sets to the reconstruction quality and demonstrate a clear benefit from the data combination. Secondly, the accuracy of the conversion from wet refractivity to dew point temperature and relative humidity profiles with the radiometer temperature profiles is examined, comparing them also to radiosonde profiles. For the least-squares collocation solution combining GPS and ground meteorological measurements, we achieve the following error figures with respect to the radiosonde reference: maximum median offset of relative refractivity error is −16% and quartiles are 5% to 40% for the lower troposphere. We further added 189 radio occultations that met our requirements. They mostly improved the accuracy in the upper troposphere. Maximum median offsets have decreased from 120% relative error to 44% at 8 km height. Dew point temperature profiles after the conversion with radiometer temperatures compare to radiosonde profiles as to: absolute dew point temperature errors in the lower troposphere have a maximum median offset of −2 K and maximum quartiles of 4.5 K. For relative humidity, we get a maximum mean offset of 7.3%, with standard deviations of 12–20%. The methodology presented allows us to reconstruct humidity profiles at any location where temperature profiles, but no atmospheric humidity measurements other than from GPS are available. Additional data sets of wet refractivity are shown to be easily integrated into the framework and strongly aid the reconstruction. Since the used data sets are all operational and available in near-realtime, we envisage the methodology of this paper to be a tool for nowcasting of clouds and rain and to understand processes in the boundary layer and at its top.
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Salman, Ahmed M., Ibrahim A. Ibrahim, Hamada M. Gad et Tharwat M. Farag. « Effects of Air Temperature on Combustion Characteristics of LPG Diffusion Flame ». Materials Science Forum 1008 (août 2020) : 128–38. http://dx.doi.org/10.4028/www.scientific.net/msf.1008.128.
Texte intégralRésumé :
In the present study, the combustion characteristics of LPG gaseous fuel diffusion flame at elevated air temperatures were experimentally investigated. An experimental test rig was manufactured to examine a wide range of operating conditions. The investigated parameters are the air temperatures of 300, 350, 400, 450, and 500 K with constant percentage of nitrogen addition in combustion air stream of 5 % to give low oxygen concentration of 18.3 % by mass at constant air swirl number, air to fuel mass ratio, and thermal load of 1.5, 30, and 23 kW, respectively. The gaseous combustion characteristics were represented as axial and radial temperatures distributions, temperatures gradient, visible flame length and species concentrations. The results indicated that as the air temperature increased, the chemical reaction rate increased and flame volume decreased, the combustion time reduced leading to a reduction in flame length. The NO concentration reaches its maximum values near the location of the maximum centerline axial temperature. Increasing the combustion air temperature by 200 K, the NO consequently O2 concentrations are increased by about % 355 and 20 % respectively, while CO2 and CO concentrations are decreased by about % 21 and 99 % respectively, at the combustor end.