scholarly journals Experimental Study of Temperature Effect on Human Skin: Discussion of Methodology

2013 ◽  
Vol 10 ◽  
pp. 71-76 ◽  
Author(s):  
Ahmad Rasdan Ismail ◽  
Abu Bakar Rosli ◽  
Norfadzilah Jusoh
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Experimental Studies ◽  
Controlled Environment ◽  
Cooling Conditions ◽  
Air Temperatures ◽  
Local Supply ◽  
Thermoregulatory System ◽  
Environment Chamber ◽  
Basic Features

This paper present the discussion of methods used in experimental studies of thermal comfort that only focus on the effect skin temperature of human. The study was conducted human subject tests in a controlled environment chamber for cooling conditions. This study was measure in the test climate chamber at Universiti Malaysia Pahang. Three broad methodology categories are compared which are experiments in which subjects have control of air temperature, relative humidity or neither. The local supply air temperatures were at 19, 25 and 32 °C while relative humidity was at 40, 55 and 70%. Together with a previously proposed diagram of basic features of the human thermoregulatory system may be used to specify limits for air temperature and relative humidity in the indoor environment.

Effect of air temperature on the abomasal and small intestinal digestion of a milk substitute diet given to young calves

1989 ◽  
Vol 48 (1) ◽  
pp. 67-74 ◽  
Author(s):  
M. S. Cockram ◽  
T. G. Rowan
Keyword(s):  
Proteolytic Activity ◽  
Air Temperature ◽  
Controlled Environment ◽  
Apparent Digestibility ◽  
Air Temperatures ◽  
Intestinal Digestion ◽  
Milk Substitute ◽  
Small Intestinal ◽  
Environment Chamber

ABSTRACTTwelve Friesian calves were each fitted with an abomasal cannula. The calves were placed in a controlled environment chamber and given a milk substitute diet in buckets at 12-h intervals. The calves were exposed to air temperatures of 25°C from 4 to 10 days of age, 5°C from 11 to 14 days of age, and 25°C at 15 days of age. At 9, 10, 11, 14 and 15 days of age, the abomasal contents of the calves were sampled at 2-h intervals and the temperature and pH of the abomasal contents were recorded at 40-min intervals for a period of 12 h. The rectal and abomasal temperatures of the calves were lower at 11 days of age than at 10 days of age, and were greater at 15 days of age than at 14 days of age (P < 0·05).In a similar experiment four Friesian calves were each fitted with an ileal re-entrant cannula. The calves were exposed to air temperatures of 25°C from 5 to 19 days of age, 5°C from 20 to 26 days of age, and 25CC at 27 days of age. At 18, 19, 20, 26 and 27 days of age the ileal contents of the calves were collected and sampled for a period of 12 h.No significant effects of the air temperatures of 25° and 5°C on the abomasal digestion (acidity and proteolytic activity of the abomasal contents) and ileal apparent digestibility of the diet were found.

scholarly journals Quantifying the Independent Influences of Land Cover and Humidity on Microscale Urban Air Temperature Variation in Hot Summer: Methods of Path Analysis and Genetic SVR

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1377
Author(s):  
Weifang Shi ◽  
Nan Wang ◽  
Aixuan Xin ◽  
Linglan Liu ◽  
Jiaqi Hou ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Land Cover ◽  
Path Analysis ◽  
Temperature Variation ◽  
Direct Effect ◽  
Air Temperature ◽  
Urban Areas ◽  
Support Vector ◽  
Urban Air ◽  
Air Temperatures

Mitigating high air temperatures and heat waves is vital for decreasing air pollution and protecting public health. To improve understanding of microscale urban air temperature variation, this paper performed measurements of air temperature and relative humidity in a field of Wuhan City in the afternoon of hot summer days, and used path analysis and genetic support vector regression (SVR) to quantify the independent influences of land cover and humidity on air temperature variation. The path analysis shows that most effect of the land cover is mediated through relative humidity difference, more than four times as much as the direct effect, and that the direct effect of relative humidity difference is nearly six times that of land cover, even larger than the total effect of the land cover. The SVR simulation illustrates that land cover and relative humidity independently contribute 16.3% and 83.7%, on average, to the rise of the air temperature over the land without vegetation in the study site. An alternative strategy of increasing the humidity artificially is proposed to reduce high air temperatures in urban areas. The study would provide scientific support for the regulation of the microclimate and the mitigation of the high air temperature in urban areas.

INFLUENCE OF TEMPERATURE AND HUMIDITY ON THE EMERGENCE BEHAVIOUR OF ANAX JUNIUS (ODONATA: AESHNIDAE)

1973 ◽  
Vol 105 (7) ◽  
pp. 975-984 ◽  
Author(s):  
Robert Trottier
Keyword(s):  
Relative Humidity ◽  
Water Temperature ◽  
Air Temperature ◽  
Water Surface ◽  
Average Speed ◽  
Anax Junius ◽  
Air Temperatures ◽  
Stage 4 ◽  
Temperature And Humidity ◽  
Three Stages

AbstractEmergence from the water of Anax junius Drury normally occurred after sunset. The onset was affected independently by water temperature and air temperature; low water temperature and high air temperature delayed the onset of emergence. In the field, the net vrtical distance travelled above the water, before ecdysis, was positively correlated with air temperature. In the laboratory, the vertical distance travelled above the water was greatest when air and water temperatures were approximately the same. The average speed of climbing to the first resting position above the water surface was faster at high than low water temperature, but the average speed of climbing from there to the final position, where ecdysis occurred, was reduced due to the effects of air temperature and humidity. Air temperatures below 12.6 °C were found to retard ecdysis and larvae returned to the water and emerged early the following day making the final process of emergence and ecdysis diurnal instead of nocturnal. The duration of ecdysis was shorter at high than low air temperatures and only the first three stages, as arbitrarily defined, were longer at low than high relative humidity; stage 4, shortened with low relative humidity. This study shows that A. Junius, emerging from the water is affected at first by the temperature experienced when submerged, but it becomes gradually and cumulatively affected by air temperature and humidity while climbing to the ecdysial position and moulting.

scholarly journals WATER-CONTAINING ABILITY OF COTTON LEAVES UNDER DIFFERENT TEMPERATURE CONDITIONS

2019 ◽  
pp. 164-166
Author(s):  
Alisher Muradullaevich Muradullaev
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Water Holding Capacity ◽  
Relative Resistance ◽  
Cotton Variety ◽  
Temperature Conditions ◽  
Control Option ◽  
Air Temperatures ◽  
Water Holding

This article presents the results of studies on the change of the water-holding ability in leaves of some varieties and lines of cotton under the influence of various high air temperatures (I control option from +24.6 to + 35.4 °C; II option - from +36.4 to +45, 1 °C; III option - from +39.5 to + 48.4 °C). At a high air temperature of + 48.4 °C, the water-holding capacity of the leaves in varieties Surkhan-14, Istiklol-14, Bukhara-102 was 26.2; 24.6; 26.4%, which indicates the relative resistance of these varieties to high air temperatures. KEYWORDS: cotton, variety, line, high air temperature, relative humidity, water holding ability.

scholarly journals Variation of Frost Roughness on a Flat Plate Under Forced Convection

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Tongxin Zhang ◽  
Dennis L. O’Neal ◽  
Stephen T. McClain
Keyword(s):  
Relative Humidity ◽  
Surface Temperature ◽  
Air Temperature ◽  
Environmental Conditions ◽  
Mean Square ◽  
Empirical Correlations ◽  
Testing Conditions ◽  
Air Temperatures ◽  
Photogrammetric Method ◽  
Grain Roughness

Abstract Experiments were conducted on a cold flat aluminum plate to characterize the variation of frost roughness over both time and location on the surfaces. The testing conditions included air temperatures from 8 to 16 °C, wall temperatures from −20 to −10 °C, relative humidities from 60 to 80%, and air velocities from 0.5 to 2.5 m/s. Each test lasted 2 h. A 3D photogrammetric method was employed to measure the variation in frost root-mean-square height and skewness by location and time. These data were used to develop the equivalent sand-grain roughness for the frost at different locations and time. The experimental results showed that frost roughness varied by location and changed with time. For the environmental conditions in this study, relative humidity and air temperature were the most important factors determining changes in the peak frost roughness. For example, at an air temperature of 12 °C and a surface temperature of −15 °C, the frost roughness peaked at about 40 min for a relative humidity of 80% and 90 min for a relative humidity of 60%. Empirical correlations were provided to describe the relationships between the environmental conditions and the appearance of the peak frost roughness.

scholarly journals Using Leaf Temperature to Improve Simulation of Heat and Drought Stresses in a Biophysical Model

Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Ruchika S. Perera ◽  
Brendan R. Cullen ◽  
Richard J. Eckard
Keyword(s):  
Heat Stress ◽  
Air Temperature ◽  
Energy Budget ◽  
Perennial Ryegrass ◽  
Measured Data ◽  
Leaf Temperature ◽  
Biophysical Model ◽  
Controlled Environment ◽  
Air Temperatures ◽  
Environment Experiment

Despite evidence that leaf temperatures can differ by several degrees from the air, crop simulation models are generally parameterised with air temperatures. Leaf energy budget is a process-based approach that can be used to link climate and physiological processes of plants, but this approach has rarely been used in crop modelling studies. In this study, a controlled environment experiment was used to validate the use of the leaf energy budget approach to calculate leaf temperature for perennial pasture species, and a modelling approach was developed utilising leaf temperature instead of air temperature to achieve a better representation of heat stress impacts on pasture growth in a biophysical model. The controlled environment experiment assessed the impact of two combined seven-day heat (control = 25/15 °C, day/night, moderate = 30/20 °C, day/night, and severe = 35/25 °C, day/night) and drought stresses (with seven-day recovery period between stress periods) on perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.) and chicory (Cichorium intybus L.). The leaf temperature of each species was modelled by using leaf energy budget equation and validated with measured data. All species showed limited homeothermy with the slope of 0.88 (P < 0.05) suggesting that pasture plants can buffer temperature variations in their growing environment. The DairyMod biophysical model was used to simulate photosynthesis during each treatment, using both air and leaf temperatures, and the patterns were compared with measured data using a response ratio (effect size compared to the well-watered control). The effect size of moderate heat and well-watered treatment was very similar to the measured values (~0.65) when simulated using T leaf, while T air overestimated the consecutive heat stress impacts (0.4 and 0). These results were used to test the heat stress recovery function (Tsum) of perennial ryegrass in DairyMod, finding that recovery after heat stress was well reproduced when parameterized with T sum = 20, while T sum = 50 simulated a long lag phase. Long term pasture growth rate simulations under irrigated conditions in south eastern Australia using leaf temperatures predicted 6–34% and 14–126% higher pasture growth rates, respectively at Ellinbank and Dookie, during late spring and summer months compared to the simulations using air temperatures. This study demonstrated that the simulation of consecutive heat and/or drought stress impacts on pasture production, using DairyMod, can be improved by using leaf temperatures instead of air temperature.

scholarly journals Wet-Bulb Temperature from Relative Humidity and Air Temperature

2011 ◽  
Vol 50 (11) ◽  
pp. 2267-2269 ◽  
Author(s):  
Roland Stull
Keyword(s):  
Gene Expression ◽  
Relative Humidity ◽  
Sea Level ◽  
Air Temperature ◽  
Mean Absolute Error ◽  
Gene Expression Programming ◽  
Absolute Error ◽  
Sea Level Pressure ◽  
Air Temperatures ◽  
Low Humidity

AbstractAn equation is presented for wet-bulb temperature as a function of air temperature and relative humidity at standard sea level pressure. It was found as an empirical fit using gene-expression programming. This equation is valid for relative humidities between 5% and 99% and for air temperatures between −20° and 50°C, except for situations having both low humidity and cold temperature. Over the valid range, errors in wet-bulb temperature range from −1° to +0.65°C, with mean absolute error of less than 0.3°C.

Modeling of Basil Leaves Drying by GA–ANN

2013 ◽  
Vol 9 (4) ◽  
pp. 393-401 ◽  
Author(s):  
Amin Taheri-Garavand ◽  
Shahin Rafiee ◽  
Alireza Keyhani ◽  
Payam Javadikia
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Relative Humidity ◽  
Moisture Content ◽  
Air Temperature ◽  
High Accuracy ◽  
Air Velocity ◽  
Feed Forward Neural Network ◽  
Air Temperatures ◽  
Hidden Layer

AbstractIn this research, the experiment is done by a dryer. It could provide any desired drying air temperature between 20 and 120°C and air relative humidity between 5 and 95% and air velocity between 0.1 and 5.0 m/s with high accuracy, and the drying experiment was conducted at five air temperatures of 40, 50, 60, 70 and 80°C and at three relative humidity 20, 40 and 60% and air velocity of 1.5, 2 and 2.5 m/s to dry Basil leaves. Then with developed Program in MATLAB software and by Genetic Algorithm could find the best Feed-Forward Neural Network (FFNN) structure to model the moisture content of dried Basil in each condition; anyway the result of best network by GA had only one hidden layer with 11 neurons. This network could predict moisture content of dried basil leaves with correlation coefficient of 0.99.

scholarly journals Reducing misclassified precipitation phase in conceptual models using cloud base heights and relative humidity to adjust air temperature thresholds

2021 ◽  
Author(s):  
Lic James M. Feiccabrino
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Conceptual Models ◽  
Phase Changes ◽  
Cloud Base ◽  
Temperature Threshold ◽  
Air Temperatures ◽  
Low Cloud ◽  
Precipitation Phase ◽  
Cloud Base Height

Abstract In cold region, conceptual models assigned precipitation phase, liquid (rain) or solid (snow), cause vastly different atmospheric, hydrological, and ecological responses, along with significant differences in evaporation, runoff, and infiltration fates for measured precipitation mass. A set air temperature threshold (ATT) applied to the over 30% annual precipitation events occurring with surface air temperatures between −3 and 5 °C resulted in 11.0 and 9.8% misclassified precipitation in Norway and Sweden, respectively. Surface air temperatures do not account for atmospheric properties causing precipitation phase changes as snow falls toward the ground. However, cloud base height and relative humidity (RH) measured from the surface can adjust ATT for expected hydrometeor-atmosphere interactions. Applying calibrated cloud base height ATTs or a linear RH function for Norway (Sweden) reduced to 4.3% (2.8%) and 14.6% (8.9%) misclassified precipitation, respectively. Cloud base height ATTs had lower miss-rates with low cloud bases, 100 m in Norway and 300 m in Sweden. Combining the RH method with cloud base ATT in low cloud conditions resulted in 16.1 and 10.8% reduction in misclassified precipitation in Norway and Sweden, respectively. Therefore, the conceptual model output should improve through the addition of available surface data without coupling to an atmospheric model.

scholarly journals EXPERIMENTAL RESEARCH OF FIRES IN GRASSY ECOSYSTEMS

Fire Safety ◽  
2020 ◽  
Vol 35 ◽  
pp. 35-40
Author(s):  
A. Kuzyk ◽  
V. Tovaryanskyi ◽  
K. Drach
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Fire Hazard ◽  
Experimental Studies ◽  
Steppe Zone ◽  
Fire Spread ◽  
Forest Steppe ◽  
Spread Rate ◽  
Natural Ecosystems

Formulation of the problem. The fire hazard of grass ecosystems depends on many factors that determine the proper condition of the combustible material and support the burning process. The most important indicators of danger are the condition and humidity of grass. The main external factors of influence on the occurrence and spread of fires in natural ecosystems are: air temperature and air relative humidity, precipitation, wind speed. The urgent task is to determine the rate of spread of fires in grassy ecosystems. The purpose of this work is to establish the features of occurrence and spread out of grass fires in the forest-steppe conditions   of Ukraine on the basis of fire hazard analysis and experimental studies. Research methods. The studies were conducted in the forest-steppe zone in the Vinnytsia region on November 1-3, 2019. The plots with 10 m in length and 3 m in width were chosen, taking into account the wind direction along the plot. During the studies, the wind speed was in a range of 0 to 10 meters per second, the air temperature varied from 7 to 14 Celsium degrees during the day and from -3 to 12 Celsium degrees at night. The air humidity varied from 52 to 69 per cent during the day and from 72 to 84 per cent at night. The humidity of the grass was 20-22 per cent in the daytime, and 27-30 per cent at night. The fire load on the sites was 4-5 t/ha. The main results of the study. Combustion mostly did not happen since 19 p.m. till 10 a.m. because the grass cover during the night increased the moisture content due to the relative humidity increasing and drop of temperature. After 10 a.m. in clear conditions and in the presence of wind, the humidity of the grasses decreased, which facilitated their ignition and spread of fire. However, in the absence of wind, ignition did not happen. The fire spreading rate depended on wind speed and grass height. For grasses 40 cm high the fire spread rate was from 2.5 m/min (wind speed 1-2 m/s) to 3.5 m/min (wind speed 6-8 m/s). For grasses 60 cm high the fire spread rate was from 3.1 m/min (wind speed 1-2 m/s) to 12.5 m/min (wind speed 6-8 m/s). Conclusions. The rate of fire spread in grassу ecosystems depend on temperature and relative humidity, wind speed, grass humidity, height and spatial location. At night, the high humidity of grasses, caused by high relative humidity and low air temperature, hinders ignition and burning, but the fire may occur in the presence of wind in the presence of several sources of ignition with sufficient energy.

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