scholarly journals Modeling the surface stored thermal energy in asphalt concrete pavements

2016 ◽  
Vol 20 (suppl. 2) ◽  
pp. 603-610
Author(s):  
Bojan Matic ◽  
Hasan Salem ◽  
Vlastimir Radonjanin ◽  
Nebojsa Radovic ◽  
Sinisa Sremac
Keyword(s):  
Neural Networks ◽  
Regression Analysis ◽  
Wind Speed ◽  
Solar Radiation ◽  
Air Temperature ◽  
Asphalt Concrete ◽  
Concrete Pavements ◽  
New Models ◽  
Pavement Temperature ◽  
The Republic

Regression analysis is used to develop models for minimal daily pavement surface temperature, using minimal daily air temperature, day of the year, wind speed and solar radiation as predictors, based on data from Awbari, Lybia,. Results were compared with existing SHRP and LTPP models. This paper also presents the models to predict surface pavement temperature depending on the days of the year using neural networks. Four annual periods are defined and new models are formulated for each period. Models using neural networks are formed on the basis of data gathered on the territory of the Republic of Serbia and are valid for that territory.

Experimental and Theoretical Investigation of Performance of a Solar Chimney Model, Part I: Experimental Investigation

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Essaied M Shuia ◽  
Bashir H Arebi ◽  
Ibrahim A abuashe
Keyword(s):  
Experimental Data ◽  
Wind Speed ◽  
Solar Radiation ◽  
Air Temperature ◽  
Solar Collector ◽  
Experimental Results ◽  
Internal Diameter ◽  
Solar Chimney ◽  
Air Velocity ◽  
Collector Temperature

This paper presents the experimental data that was collected from small pilot solar chimney. The experimental data together with ambient conditions are used to evaluate the performance and study the behavior of the solar chimney; this data will be used for comparison with theoretical models in another paper [part II). The solar chimney prototype was designed and constructed at the Subrata Faculty of Engineering-Libya. The data were collected over several days of June 2011. The solar chimney system contains two main components; the solar collector and the solar chimney. The solar collector root‘ has a circular area of126 m3, the solar chimney is a PVC tube with internal diameter of 0.2 m and the total height of chimney is 9.3 m. The measurements include the intensity of solar radiation inside/outside the collector, temperature and velocity of air at the entrance of the chimney, temperature and speed of wind outside the collector, temperature of the ground inside collector al1d temperature measurements of air at speci?c points at different levels throughout the collector. Solar irradiance was found to affect the chimney temperature and subsequently affects chimney air velocity. The experimental results showed that temperature differences of (30 - 45°C) were recorded between the ambient temperature and that of air inside the chimney in the middle of the day, where the highest air temperature of 73.4°C was recorded at the entrance of the solar chimney. The maximum air velocity of 3.6 m/s was recorded inside the solar chimney at noon on 9 June. Wind speed outside the collector had a small effect on the speed of the air inside the chimney and tends to change slightly, hence, can neglect influence of wind speed on the performance of the system. Also the experimental results indicate that such type of system can trap a suf?cient amount of solar radiation, which elevates the air temperature to a suf?cient value able to generate enough air ?ow to operate a wind turbine to produce electricity; this means the solar chimney system for electricity production can work in the north-western part of Libya in the summer time at least.

scholarly journals A Study on Characteristics and Comparison of Evaporation Estimation Methods in Bandung

2021 ◽  
Vol 53 (2) ◽  
pp. 182-199
Author(s):  
Rusmawan Suwarman ◽  
Novitasari Novitasari ◽  
I Dewa Gede Agung Junnaedhi
Keyword(s):  
Regression Analysis ◽  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Estimation Methods ◽  
Observation Data ◽  
Weather Factor ◽  
Better Than

This study aims to understand the characteristic of evaporation and to evaluate the evaporation estimation methods to be employed in Bandung by using observation data at three different land cover characteristics sites, namely, densely vegetated area (Baleendah), densely built-up area (Ujung Berung), and mix of buildings and vegetation area (ITB). Observation data used are hourly evaporation, vapour pressure deficit, temperature, relative humidity, wind speed, and radiation. The analysis was done mostly by using statistical methods such as regression analysis and error comparison. The result shows the dominant weather factor affecting the evaporation in ITB and Ujung Berung is vapour pressure deficit, and in Baleendah is solar radiation. The methods of evaporation estimations used in this study are Trabert, Schendel, Turc, and CIMIS-Penman methods. The result shows that the original constant values of those methods are significantly correlated. However, the Schendel is found the most overestimated, and the second is Turc. The best estimated evaporation in Baleendah, ITB, and Ujung Berung is calculated using CIMIS-Penman with one hour lag of radiation, Trabert, and Calibrated Schendel, respectively. The improvement of constant value was applied to Schendel and the result is better than the original constants.

scholarly journals THERMAL CONDITIONS OF ROAD PAVEMENTS AND THEIR INFLUENCE ON MOTOR TRAFFIC

Transport ◽  
2003 ◽  
Vol 18 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Alfredas Laurinavičius ◽  
Donatas Ďygas
Keyword(s):  
Asphalt Concrete ◽  
Thermal Conditions ◽  
Climatic Conditions ◽  
Concrete Pavement ◽  
Concrete Pavements ◽  
Road Asphalt ◽  
Concrete Mixtures ◽  
Research Findings ◽  
The Republic ◽  
Asphalt Concrete Pavement

The article presents the analysis of climatic conditions in the Republic of Lithuania and describes their influence on road asphalt concrete pavement. Dependence of the main properties of asphalt concrete mixtures on tempera~re is described with the help of carried out experiments. Research findings show that the probability of plastic defomations (rutting and corrugation) in asphalt concrete pavement is higher when the pavement temperature IS 20-40 C. Ptactical application of the presented conclusions and recommendations will enable to reduce the occurrence of undesirable deformations in asphalt concrete pavements and to improve traffic conditions on the roads.

scholarly journals Investigation on the Temperature Distribution of Asphalt Overlay on the Existing Cement Concrete Pavement in Hot-Humid Climate in Southern China

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zuzhong Li ◽  
Yayun Zhang ◽  
Chunguang Fa ◽  
Xiaoming Zou ◽  
Haiwei Xie ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Prediction Model ◽  
Air Temperature ◽  
Concrete Pavement ◽  
Humid Climate ◽  
Temperature Prediction ◽  
Asphalt Overlay ◽  
Hot Humid Climate

Temperature is known to be one of the most important factors affecting the design and performance of asphalt concrete pavement. The distresses of asphalt overlay are closely related to its temperature, particularly in Guangxi, a hot-humid-climate region in China. This research is to analyze the impact of meteorological factors on temperature at 2 cm depth in asphalt overlay by ReliefF algorithm and also obtain the temperature prediction model using MATLAB. Two test sites were installed to monitor the temperatures at different pavement depths from 2014 to 2016; meanwhile, the meteorological data (including air temperature, solar radiation, wind speed, and relative humidity) were collected from the two meteorological stations. It has been found that the temperature at 2 cm depth experiences greater temperature variation, and the maximum and minimum temperatures of asphalt overlay, respectively, occur at 2 cm depth and on the surface. Besides, the results of ReliefF algorithm have also shown that the temperature at 2 cm depth is affected significantly by solar radiation, air temperature, wind speed, and the relative humidity. Based on these analyses, the prediction model of maximum temperature at 2 cm depth is developed using statistical regression. Moreover, the data collected in 2017 are used to validate the accuracy of the model. Compared with the existing models, the developed model was confirmed to be more effective for temperature prediction in hot-humid region. In addition, the analysis of rutting depth and overlay deformation for the two test sections with different materials is done, and the results have shown that reasonable structure and materials of asphalt overlay are vital to promote the high-temperature antideforming capability of pavement.

scholarly journals Ocena bioklimatycznych warunków rekreacji i turystyki w strefie polskiego Wybrzeża Bałtyku na podstawie wskaźnika UTCI = Assessment of bioclimatic conditions for recreation and tourism in the Polish Baltic coastal zone using the UTCI index

2019 ◽  
Vol 91 (2) ◽  
pp. 113-126 ◽  
Author(s):  
Czesław Koźmiński ◽  
Bożena Michalska
Keyword(s):  
Heat Stress ◽  
Wind Speed ◽  
Solar Radiation ◽  
Cold Stress ◽  
Air Temperature ◽  
Human Organism ◽  
Heat Loading ◽  
Extreme Cold ◽  
Bioclimatic Conditions ◽  
Recreation And Tourism

The quality of a given bioclimate is much affected by the atmospheric environment (taken to include solar radiation, air temperature and humidity, atmospheric pressure, wind speed and levels of atmospheric pollution), as well as by geographical factors relating to topography and cover, the drainage system and land use (Owczarek 2009, Czarnecka, Nidzgorska-Lencewicz 2010, Koźmiński, Michalska 2011, Owczarek 2012). Tourists staying in a coastal area must contend with considerable variability of weather from one day to another, or even hour by hour, in the cold half-year in particular. Changes of weather have a profound effect on the human organism, inter alia giving rise to migraines, sleep disturbances and hypersensitivity. The work described here sought to assess temporal (inter alia seasonal) and spatial variability to heat loading of the human organism characterising the Polish Baltic coastal zone, as well as the temperature of water by beaches. It was to achieve this kind of assessments of bioclimate and its impact on the human organism that the index known as the UTCI (Universal Thermal Climate Index) was devised, taking in air temperature, wind speed, air humidity and absorbed solar radiation (expressed as mean radiant temperature) (Błażejczyk & Kunert, 2011). This index represents objective changes in physiological parameters of the human organism occurring thanks to differing environmental conditions as determined in relation to a 10-point scale for heat loading of the human organism (°C) that translate into descriptive terms ranging from extreme heat stress to extreme cold stress. UTCI values referred to here were calculated using BioKlima 2.6 software - http://www.igipz.pan.pl/Bioklima-zgik.html. Six zones for the heat loading of the human organism found to be present along the Polish coast during the four seasons of the year were designated by summing the frequency of occurrence of days with a particularly stimulating effect, be this severe or very severe heat stress or severe, very severe or extreme cold stress. The UTCI-based analysis sustained conclusions as follows: - The Polish Baltic coast is found to be characterised by marked day-to-day variability in the heat loading of the human organism, particularly in the November-late May period, with the result being a significant “nuisance” represented for tourists. - Along the western part of the coast and in the area of the Bay of Puck, conditions thermoneutral for the human organism were found to dominate (accounting for more than 60% of the days in a month) over the whole period from May through to mid-October. In the case of the northern part of the coast from Darłowo to Łeba the same was found to be true of the period extending from June through to the middle ten-day period of September, creating conditions favourable for outdoor recreation. - The duration of the bathing season with mean monthly water temperatures ≥18°C is of approximately 45 days along the coast from Darłowo to Łeba, 46-50 days in the central part of the coast, 46-60 days in the area of the Bay of Gdańsk and 61-70 in the area of the Bay of Pomerania. In most years under analysis, there was no identification of a bathing season with mean monthly water temperature ≥18°C in the Kołobrzeg and Władysławowo areas. - The bioclimatic conditions most favourable for recreation and tourism were identified for the area of the Bay of Pomerania, followed by the Bay of Gdańsk. Less-favourable conditions characterise the central part of the coast, while the least favourable circumstances extend through the northern area from Darłowo to Łeba, in which the bioclimate’s stimulatory effect is strongest.- The high spatial variability characterising heat loading of the human organism that it proved possible to identify for the Polish coast offers the possibility of particular regions and seasons being selected for recreation, in relation to tourists’ health status and specific requirements.

scholarly journals Efectos de las condiciones ambientales sobre el comportamiento ingestivo en bovinos de carne en un sistema intensivo en el Valle del Sinú

2013 ◽  
Vol 13 (2) ◽  
pp. 207 ◽  
Author(s):  
Emiro Suárez P. ◽  
Sony Reza G. ◽  
Eliecer Díaz A. ◽  
Fredy García C. ◽  
Iván Pastrana V. ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Beef Cattle ◽  
Air Temperature ◽  
Ingestive Behavior ◽  
Average Weight ◽  
Zebu Cattle ◽  
Panicum Maximum ◽  
Atmospheric Variables

<p>Incrementos en la temperatura ambiental y la humedad relativa, unidas al efecto de la radiación solar, ocasionan pérdidas en el bienestar animal, afectando la conducta ingestiva y la productividad animal. Por ello el objetivo de este estudio fue analizar las relaciones entre las variables atmosféricas, como temperatura del aire, humedad relativa, velocidad del viento y radiación solar, con los tiempos de pastoreo y de rumia de bovinos cebú comercial. La investigación se llevó a cabo durante 96 días, entre julio-octubre de 2010, en el C.I. Turipaná de Corpoica (Cereté, Colombia). Bovinos machos enteros (27), con peso promedio 314 ± 29 kg, pastorearon en un área de 18 hectáreas, establecidas en <em>Panicum maximum </em>cv. Mombasa, <em>Cynodonnlem fluensis </em>y <em>Brachiaria </em>híbrido cv. Mulato II, sin disponibilidad de sombra. Se realizaron ocho evaluaciones durante 8 días dentro del periodo experimental de las variables atmosféricas e ingestivas y las anotaciones se hicieron en un lapso de 12 horas continuas (6:00 AM a 6:00 PM). Los resultados resaltan que al aumentar la temperatura del aire, humedad relativa y la radiación solar, disminuyó el tiempo de pastoreo y aumentó el tiempo de rumia, mientras que al aumentar la velocidad del viento se incrementó el tiempo de pastoreo y disminuyó el tiempo de rumia. Los resultados obtenidos indicaron que la temperatura del aire, humedad relativa, radiación solar y velocidad del viento, presentaron una influencia directa sobre el comportamiento ingestivo de los bovinos de carne manejados en sistemas intensivos (sin sombra) en el Valle del Sinú. </p><p> </p><p><strong>Effects of environmental conditions on feeding behavior in beef cattle in an intensive system in the Sinú Valley </strong></p><p>Increases in temperature and relative humidity together with the solar radiation effect are detrimental to animal welfare, affecting their behavior when it comes to feeding and digestive behavior, which affects their productivity. Therefore, the goal of this research was to analyze the link between atmospheric variables, air temperature, relative humidity, wind speed and solar radiation to the time of grazing and rumination of commercial Zebu cattle. The research took place from July to October 2010, at the Turipaná Center, Corpoica (Cereté, Colombia). Male intact bovines (27), with an average weight of 314 ± 29 kg, grazed in an area of 18 hectares, established with <em>Panicum maximum </em>cv. Mombasa, <em>Cynodonnlem fluensis </em>and <em>Brachiaria </em>hybrid cv. Mulato II, without shade availability. Eight evaluations were conducted for 8 days in the experimental period for atmospheric variables and ingestion. Notes were taken in 12 hour time frames (6:00 AM a 6:00 PM). The outcome showed that as the air temperature, relative humidity and solar radiation increased, the grazing time decreased and rumination time lasted longer. However, when wind speed increased, grazing time increased as well and rumination took less time. The results showed that the air temperature, relative humidity, solar radiation and wind speed had a direct influence on the ingestive behavior of beef cattle managed in intensive systems (shadeless) in Valle del Sinú. </p>

scholarly journals Estimating Solar Radiation Intensity from Other Meteorological Data

1969 ◽  
Vol 54 ◽  
pp. 377-389
Author(s):  
Modesto Capiel
Keyword(s):  
Regression Analysis ◽  
Solar Radiation ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Air Temperature ◽  
Meteorological Data ◽  
Solar Radiation Intensity ◽  
Period Data ◽  
The Mean ◽  
Analysis Equation

Estimates of solar radiation (Ri) by 15-day periods were calculated from other available meteorological data by multiple regression analysis of Eo = f(Ri, u, Ta) ed), and then solving for Ri from the most significant equation of the model given above. Only solar radiation wind speed (u) and air temperature (Ta) were found to correlate significantly with Eo. The solution in terms of Ri (equation /4/) then was used to obtain estimates of solar radiation for 1- to 5-day periods. The mean ratio of estimated Ri to measured Ri approached unity (0.95), while the coefficient of variation was 8.9 percent, as compared to 5.1 percent for the original 15-day period data. It was found when these were compared to measured values that neglect of air temperature reduced precision of the estimates. Equation /4/ (the indirect solution) next was evaluated on the basis of foreign data, representing extreme meteorological conditions as those in Bet Dagan, Israel and Cristobal, Panamá. This equation also was compared at the same time to a direct solution of Ri by multiple regression analysis (equation /6/), a solution which directly minimizes the deviations about Ri. Statistical data are presented which compare the precision of the estimates by either equation (/4/ and /6/).

scholarly journals Estimation of the Influence of Meteorological Factors on the Potential Evapotranspiration of Yanhe River Basin

2021 ◽  
Author(s):  
yu luo ◽  
Peng Gao ◽  
Xingmin Mu ◽  
dexun Qiu
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
River Basin ◽  
Air Temperature ◽  
Meteorological Factors ◽  
Sensitivity Coefficient ◽  
Downward Trend ◽  
Upward Trend ◽  
Temporal And Spatial

Potential evapotranspiration (ET) is an important expenditure item in the hydrological cycle. Quantitative estimation of the influence of meteorological factors on ET can provide a scientific basis for the study of the impact mechanism of climate change on the hydrological cycle. In this paper, the Penman-Monteith method was used to calculate ET. The Mann-Kendall statistical test and the Inverse Distance Weighting method were used to analyze the temporal and spatial characteristics of the sensitivity coefficient of ET to meteorological factors and contribution rate of meteorological factors to ET. And the reasons for the change of ET were quantitatively explored in combination with the change trend of meteorological factors. The results showed that the average ET in the Yanhe River Basin from 1978 to 2017 was 935.92mm. Except for Ganquan Station, ET showed an upward trend. Generally, the sensitivity coefficient of air temperature (0.08), wind speed (0.19) and solar radiation (0.42) was positive and the sensitivity coefficient of relative humidity (-0.41) was negative. But there were significant temporal and spatial differences. The upward trend of air temperature and solar radiation contributed 1.09% and 0.55% to ET. Respectively, the downward trend of wind speed contributed -0.63% And the downward trend of relative humidity contributed to -0.85% of ET. Therefore, the decrease of relative humidity did not cause the increase of ET in Yanhe River basin. The dominant factor of the upward trend of ET was air temperature. But the dominant factors of ET had significant temporal and spatial differences. The downward trend of wind speed at Ganquan Station contributed -9.16% to ET, which indicated the dominant factor of “evaporation paradox” in Ganquan area was wind speed. Generally, the increase of ET was related to air temperature, wind speed and solar radiation. And the decrease of ET was related to relative humidity.

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