scholarly journals Numerische Simulation von Temperaturgradienten und thermisch induzierten Eigenspannungen in Natursteinplatten infolge von Sonneneinstrahlung / Simulation of Temperature Gradients and Stresses in Natural Stone Plates under Solar Radiation

1998 ◽  
Vol 4 (1) ◽  
pp. 53-72 ◽  
Author(s):  
H. Sadouki ◽  
F. H. Wittmann
Keyword(s):  
Solar Radiation ◽  
Thermal Loading ◽  
Swelling Pressure ◽  
Natural Stone ◽  
Maximum Temperature ◽  
Selective Absorption ◽  
Chemical Attack ◽  
Physical Attack ◽  
Thermal Dilatation ◽  
Micro Organisms

Abstract The interaction between micro-organisms and natural stone surfaces has been studied in great detail in the past. The destructive mechanisms of micro-organisms can be roughly subdivided into (a) chemical attack and (b) physical attack. Microorganisms may physically destroy the structure of stones by creating an inter-granular swelling pressure. Recently, it has been shown experimentally that black spots formed by yeast-like fungi lead to a local temperature increase by selective absorption of solar radiation. The maximum temperature observed for clean marble surfaces remained below the maximum temperature observed on inoculated surfaces. As a consequence, thermal dilatation of inoculated marble was shown to be more important. Destruction of the heated stone occurs predominantly if there exists a thermal gradient. In this paper, temperature distribution in clean and stained marble plates have been simulated numerically. Thermal eigenstresses have been determined. It is shown that tensile stresses of up to 5 N/mm2 can be expected. This may cause damage in weak zones of the surface. A sudden driving rain leads to much higher stresses. Cyclic thermal loading may eventually destroy the surface by fatigue.

Ecological Niche Modeling Predicting the Potential Distribution of African Horse Sickness Virus from 2020 - 2060

2021 ◽  
Author(s):  
Ayalew Assefa ◽  
Abebe Tibebu ◽  
Amare Bihon ◽  
Alemu Dagnachew ◽  
Yimer Muktar
Keyword(s):  
Solar Radiation ◽  
Ecological Niche ◽  
Annual Precipitation ◽  
Maximum Temperature ◽  
Mean Annual Precipitation ◽  
African Horse Sickness ◽  
Diurnal Range ◽  
Annual Minimum Temperature ◽  
Precipitation Seasonality ◽  
Vector Borne

Abstract African horse sickness is a vector-borne, non-contagious and highly infectious disease of equines caused by African Horse Sickness viruses (AHSv) that mainly affect horses. The occurrence of the disease causes huge economic impacts because of its fatality rate is high, trade ban and disease control costs. In planning of vectors and vector borne diseases, the application of Ecological niche models (ENM) used an enormous contribution in exactly delineating the suitable habitats of the vector. We developed an ENM with the objective of delineating the global suitability of AHSv outbreaks retrospective based on data records from 2005–2019. The model was developed in R software program using Biomod2 package with an Ensemble modeling technique. Predictive environmental variables like mean diurnal range, mean precipitation of driest month(mm), precipitation seasonality (cv), mean annual maximum temperature (oc), mean annual minimum temperature (oc) mean precipitation of warmest quarter(mm), mean precipitation of coldest quarter (mm) mean annual precipitation (mm), solar radiation (kj /day), elevation/altitude (m), wind speed (m/s) were used to develop the model. From these variables, solar radiation, mean maximum temperature, average annual precipitation, altitude and precipitation seasonality contributed 36.83%, 17.1%, 14.34%, 7.61%, and 6.4%, respectively. The model depicted the sub-Sahara African continent as the most suitable area for the virus. Mainly Senegal, Burkina Faso, Niger, Nigeria, Ethiopia, Sudan, Somalia, South Africa, Zimbabwe, Madagascar and Malawi are African countries identified as highly suitable countries for the virus. Besides, OIE-listed disease-free countries like India, Australia, Brazil, Paraguay and Bolivia have been found suitable for the virusThis model can be used as an epidemiological tool in planning control and surveillance of diseases nationally or internationally.

scholarly journals A study of improving thermal environment of external louver through establishment of test bed

2018 ◽  
Vol 7 (3.3) ◽  
pp. 373
Author(s):  
Sun Pil Kwon ◽  
Jae Jun Jung ◽  
Byoung Jo Jung
Keyword(s):  
Statistical Analysis ◽  
Solar Radiation ◽  
Thermal Effect ◽  
Thermal Load ◽  
Thermal Environment ◽  
Direct Solar Radiation ◽  
Maximum Temperature ◽  
Test Bed ◽  
Solar Insolation ◽  
Maximum Temperature Difference

Background/Objectives: To improve a thermal load by increasing internal thermal effect of a building from direct solar radiation through an increase of glass windows.Methods/Statistical analysis: Through the establishment of test beds of the same size, the data of temperature, humidity, solar insolation and PMV of each test bed with or without external louver are acquired to analyze thermal environmental with the simulation.Findings: For the analysis of thermal environment, the amount of energy consumption has been analyzed through the simulation and the data of temperature, humidity, solar insolation and PMV have been acquired for the analysis. With the simulation, about 20% energy saving has been confirmed and the daily averages of temperature and humidity between 8AM to 7PM have been calculated to calculate the maximum temperature difference to be 9.4℃. The solar insolation between 9AM and 7PM was 300W/m2 or below.Improvements/Applications: The improvement of thermal effect with an external louver has been confirmed. It may be applied to the louver system to improve building thermal environment, awning to control direct solar radiation, blind to improve uniformity of illumination intensity toward building during daytime, external blind and ceiling louver system. 

scholarly journals Assessment of Heat Stress and Cloudiness Probabilities in Post-Flowering of Wheat and Canola in The Southern Cone of South America

2021 ◽  
Author(s):  
Gonzalo Martín Rivelli ◽  
María Elena Fernández Long ◽  
Leonor Gabriela Abeledo ◽  
Daniel Calderini ◽  
Daniel Julio Miralles ◽  
...  
Keyword(s):  
Heat Stress ◽  
Solar Radiation ◽  
South America ◽  
Southern Cone ◽  
Maximum Temperature ◽  
Curvilinear Relationship ◽  
Climate Scenarios ◽  
Incident Solar Radiation ◽  
Probability Of Occurrence ◽  
Combined Stresses

Abstract Episodes of heat stress constrain crop production and will be aggravated in the near future according to short and medium-term climate scenarios. Global increase in cloudiness has also been observed, decreasing the incident solar radiation. This work was aimed to quantify the probability of occurrence of heat stress and cloudiness, alone or combined, during the typical post-flowering period of wheat and canola in the Southern Cone of South America. Extended climate series (last 3-5 decades with daily register) of 33 conventional weather stations from Argentina, Brazil, Chile and Uruguay (23ºS to 40ºS) were analysed considering the period from September to December. Two different daily events of heat stress were determined: i) maximum daily temperature above 30ºC (T>30ºC), and ii) 5ºC above the historical average maximum temperature of that day (T+5ºC). A cloudiness event was defined in our work as incident solar radiation 50% lower than the historical average radiation of that day (R50%). The T>30ºC event increased its probability of occurrence throughout the post-flowering phase, from September to December. By contrast, the risk of T+5ºC event decreased slightly, just like for R50%, and the higher the latitude, the lower the probability of R50%. The T>30ºC plus R50% combined stresses reached greater cumulated probabilities during post-flowering, compared to T+5ºC plus R50%, being 42% vs. 15% in northernmost locations, 26% vs. 19% in central (between 31ºS to 35ºS), and 28% vs. 1% in southernmost locations, respectively. A curvilinear relationship emerged between the monthly probability of combined stresses and the number of days with stress per month. In summary, T>30ºC was the most frequent thermal stress during post-flowering in wheat and canola. Both combined stresses had a noticeable risk of occurrence, but T>30ºC plus R50% was the highest. Evidence of the recent past and current occurrence of heat stress individually, and its combination with cloudiness events during post-flowering of temperate crops, serves as a baseline for future climate scenarios in main cropped areas in the Southern Cone of South America.

scholarly journals Research On Solar Energy Collector With Cell Polycarbonate Absorber

2015 ◽  
Vol 1 ◽  
pp. 213
Author(s):  
Henriks Putāns ◽  
Viktorija Zagorska ◽  
Imants Ziemelis ◽  
Zanis Jesko
Keyword(s):  
Experimental Investigation ◽  
Solar Radiation ◽  
Air Temperature ◽  
Heat Carrier ◽  
Heat Insulation ◽  
Ambient Air ◽  
Maximum Temperature ◽  
Experimental Examination ◽  
Ambient Air Temperature ◽  
Flat Plate Solar Collector

A flat plate solar collector with cell polycarbonate absorber and transparent cover has been made and its experimental investigation carried out. The collector consists of a wooden box, into which, a layer of heat insulation with a mirror film and 4 mm thick cell polycarbonate sheet, as the absorber, are placed. The coherence between collector’s efficiency, heat carrier and ambient air temperature, as well as intensity of the solar radiation and heat power in the experimental investigation has been obtained. During the experimental examination the maximum temperature of the heat carrier reached 80˚C at the intensity of solar radiation about 0.8 kW/m2 and ambient air temperature around 32˚C. The efficiency of the collector reached 33-60%, depending on the intensity of solar radiation and surrounding air temperature.

Thermal loading of concrete bridges

1984 ◽  
Vol 11 (3) ◽  
pp. 423-429 ◽  
Author(s):  
Malcolm J. S. Hirst
Keyword(s):  
Solar Radiation ◽  
Engineering Design ◽  
Computer Model ◽  
Parametric Study ◽  
Structural Engineering ◽  
Thermal Loading ◽  
Design Method ◽  
Field Measurements ◽  
Concrete Bridges ◽  
Frequency Distributions

This paper presents the results of a parametric study into the thermal loading of concrete bridges by solar radiation. All results were obtained using a computer model calibrated from field measurements. The model computes the loading parameters from the bridge characteristics and the standard daily records of the weather bureau. The design method given uses an effective thickness concept to find the effects of a wearing course on the temperature profile of the underlying bridge. Thermal loading depends on climate and is extremely variable. Histograms are presented, which show the frequency distributions of the loading parameters for sample bridges at three Australian sites covering a range of climatic regimes from tropical to temperate. Key words: bridges, concrete, loads, temperature, solar radiation, structural engineering, design chart.

scholarly journals Design of Transparent Metasurfaces Based on Asymmetric Nanostructures for Directional and Selective Absorption

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3751
Author(s):  
Dong Wu ◽  
Yang Meng ◽  
Chang Liu
Keyword(s):  
Solar Radiation ◽  
Energy Saving ◽  
Noble Metals ◽  
Near Infrared ◽  
Low Cost ◽  
Infrared Light ◽  
Manufacturing Cost ◽  
Selective Absorption ◽  
Metal Insulator Metal ◽  
Peak Value

Maximizing the solar heat gain through windows in winter and minimizing the solar radiation entering the room in summer are of great significance for the energy saving of buildings. Here, we present a new idea for transparent metasurfaces, based on asymmetric metal/insulator/metal (MIM) nanostructures, which can be switched back and forth between absorbing and reflecting solar radiation by reversing the sample orientation. Owing to the fundamental mode of a low-quality-factor resonance, a selective near-infrared absorption is obtained with an absorption peak value of 90% upon front illumination. The average solar absorption (45%) is about 10% higher than that (35%) of reported transparent absorbers. The near-infrared light is also strongly and selectively reflected upon back illumination and a reflection peak value above 70% is observed. Meanwhile, the average visible transmission of the metasurface is above 60%, which is about 1.6 times that (36%) of previous transparent metasurface absorbers. In addition, Cu material can replace the noble metals in this work, which will greatly reduce the manufacturing cost. Owing to the attractive properties of directional and selective absorption, passive operation mode, and low cost of the materials, the metasurfaces have promising prospects in building energy saving or other solar applications where surface transparency is desirable.

Performance of Dosage of Ceramic Chopped Fibers in Aluminous Cement-Based Composites after Exposure to High Temperatures

2016 ◽  
Vol 722 ◽  
pp. 38-43 ◽  
Author(s):  
Marcel Jogl
Keyword(s):  
Maximum Temperature ◽  
High Temperature Application ◽  
Temperature Resistance ◽  
Chemical Attack ◽  
Humid Environment ◽  
The Matrix ◽  
Temperature Application ◽  
Aluminous Cement ◽  
Different Levels ◽  
Excellent Chemical

The results of an experimental investigation of the influence of chopped alumina-silica bulk fibers on residual mechanical properties of lightweight cement-based composites for high temperature application are obtained. The matrix of studied specimens is based on aluminous cement, because of its sufficient temperature resistance over 1000 °C. Thermal ceramic bulk fiber offer a maximum temperature range of between 1200° to 1500 °C. They also provide excellent chemical stability and resistance to chemical attack. If wet by oil or water, thermal and physical properties will be fully restored after drying. The benefits of using ceramic bulk fibers were evaluated by the results of physical and mechanical testing; compressive strength, flexural strength and bulk density were determined on the different levels of temperature loading. The prismatic specimens, having dimensions of 40×40×160 mm3, are cured 28 days in humid environment and after that time dried and subjected to temperatures of 600 °C and 1000 °C for 3 hours. The experimental composites differed in doses of fibers, which are 0.0 %, 0.5 % and 2.0 % by volume.

scholarly journals Study of Affecting Factors of Meteorological Parameters on Solar Radiation in Kathmandu Valley

The Batuk ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 72-80
Author(s):  
Prakash M. Shrestha ◽  
Khem N. Poudyal ◽  
Narayan P. Chapagain ◽  
Indra B. Karki
Keyword(s):  
Solar Radiation ◽  
Meteorological Parameters ◽  
Weather Conditions ◽  
Global Solar Radiation ◽  
Solar Irradiation ◽  
Maximum Temperature ◽  
Affecting Factors ◽  
Air Mass ◽  
High Level ◽  
Relative Sunshine

Solar radiation data are great significance for solar energy systems. This study aimed to estimate monthly and seasonal average daily global solar radiation on a horizontal surface in Kathmandu (27.7oN, 85.5oE, 1350 masl), Nepal, by using CMP6 pyranometer in 2012. The influence of the global solar irradiation from different physical as well as meteorological parameters was analyzed. Besides this, the research highlighted that there is high level of fluctuation of the measured value of global solar irradiance due to local weather conditions. As a result of this measurement, the maximum, minimum monthly and yearly mean solar radiation values were (21.32 ± 4.14) MJ/m2/day in May,(10.93 ± 2.03) MJ/m2/day in January and (16.68 ± 4.60)MJ/m2/day found respectively. Annual average of clearness index, maximum temperature, minimum temperature, relative sunshine hour, air mass are 0.51 ± 0.12, (26.23 ± 4.96)oC, (12.38 ± 6.83)oC, 0.57 ± 0.165 and 1.54 ± 0.42 respectively. There is positive correlation of maximum temperature and negative correlation of air mass with global solar radiation.

scholarly journals Future climate uncertainty and spatial variability over Tamilnadu State, India

2015 ◽  
Vol 17 (1) ◽  
pp. 175-185
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Minimum Temperature ◽  
Climate Models ◽  
Regional Climate ◽  
Future Climate ◽  
Maximum Temperature ◽  
Projection Data ◽  
Climate Uncertainty

<div> <p>The present study analyses future climate uncertainty for the 21st century over Tamilnadu state for six weather parameters: solar radiation, maximum temperature, minimum temperature, relative humidity, wind speed and rainfall. The climate projection data was dynamically downscaled using high resolution regional climate models, PRECIS and RegCM4 at 0.22&deg;x0.22&deg; resolution. PRECIS RCM was driven by HadCM3Q ensembles (HQ0, HQ1, HQ3, HQ16) lateral boundary conditions (LBCs) and RegCM4 driven by ECHAM5 LBCs for 130 years (1971-2100). The deviations in weather variables between 2091-2100 decade and the base years (1971-2000) were calculated for all grids of Tamilnadu for ascertaining the uncertainty. These deviations indicated that all model members projected no appreciable difference in relative humidity, wind speed and solar radiation. The temperature (maximum and minimum) however showed a definite increasing trend with 1.8 to 4.0&deg;C and 2.0 to 4.8&deg;C, respectively. The model members for rainfall exhibited a high uncertainty as they projected high negative and positive deviations (-379 to 854 mm). The spatial representation of maximum and minimum temperature indicated a definite rhythm of increment from coastal area to inland. However, variability in projected rainfall was noticed.</p> </div> <p>&nbsp;</p>

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