scholarly journals Thermal Stress in Concrete Slab of the Airfield Pavement

2020 ◽  
Vol 50 (1) ◽  
pp. 259-268 ◽  
Author(s):  
Małgorzata Linek ◽  
Piotr Nita
Keyword(s):  
Thermal Stress ◽  
Air Temperature ◽  
Concrete Slab ◽  
Annual Basis ◽  
Construction Design ◽  
Linear Dimensions ◽  
Individual Structure ◽  
The Subject ◽  
Geometric Solutions ◽  
Daily Changes

AbstractStress occurring in concrete pavement slab changes on daily and annual basis. Daily changes of air temperature in between environments depend on the following: latitude where the structure is located and season. Change of air temperature causes the variable thermal stress of a slab and consequently change of its linear dimensions (slab extension or shortening. “Thermal balance of pavement” prepared for individual structure solutions, should be the basis for construction design and geometric solutions concerning air field structure. This publication refers only to natural changes of temperature conditions of the environment. Other phenomena occurring on concrete airfield pavement under the influence of imposed thermal loads will be the subject of another publication in this regard.

scholarly journals Analysis of temperature gradient in concrete pavement

2018 ◽  
Vol 67 (4) ◽  
pp. 59-70
Author(s):  
Grzegorz Rogojsz
Keyword(s):  
Thermal Stress ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Air Temperature ◽  
Experimental Research ◽  
Analytical Methods ◽  
Concrete Slab ◽  
Climatic Conditions ◽  
Concrete Pavement

The paper presents the results of experimental research that is the continuation of the research conducted as a part of a Ph.D. dissertation. The experimental research consisted in measuring the temperature at various depths inside a concrete slab, including its surface, and measuring the air temperature. The temperature distribution was measured on a concrete slab with dimensions similar to real road slab dimensions. The aim of the research was to determine the temperature gradient in the concrete slab in Polish climatic conditions and to verify the available analytical methods. Keywords: temperature gradient, concrete pavement, thermal stress in concrete pavement.

A field survey of thermal stress in New Guinea villagers

1974 ◽  
Vol 268 (893) ◽  
pp. 393-400 ◽  
Keyword(s):  
Thermal Stress ◽  
Wind Speed ◽  
Air Temperature ◽  
New Guinea ◽  
Radiant Heat ◽  
Mean Radiant Temperature ◽  
Air Temperatures ◽  
Fluid Deficit ◽  
The Subject ◽  
Radiant Temperature

A survey to assess the thermal stress experienced by New Guinea villagers during everyday life was conducted on about 30 adults of each sex at each of two places - the villages of Kaul, on Karkar Island, and Lufa in the highlands. An observer accompanied each subject throughout the day, continuously recording his activity, his adjustments of clothing, and the time he spent in sunshine and in shade. Every 20 min, measurements of air temperature, humidity, and wind speed, and the mean radiant temperature in sunshine and shade, were made near the subject. Air temperature in the villagers’ houses was continuously recorded by thermograph. A preliminary analysis of the results indicates that people at Lufa were exposed to lower air temperature, humidity, and wind speed, but greater radiant heat, than those at Kaul. The average thermal stress, as calculated by the method of Belding & Hatch, was only slightly less at Lufa than at Kaul. At Kaul the air temperature indoors was much the same as that outdoors, but at Lufa it was 2 °C higher than outdoors. Air temperature and mean radiant temperature at Kaul were considerably higher in houses built of galvanized iron than in those of traditional bush materials. Men working in a copra drier were intermittently exposed to air temperatures over 71 °C, and to globe-thermometer temperatures as high as 110 °C. Kaul people engaged in their normal pursuits were found to lose an average of 2196 g of sweat in 7.5 h and to replace about half of it by drinking, thus incurring a fluid deficit of 1172 g, equivalent to 2.1 % of body mass.

XX.—On a See-Saw of Barometric Pressure, Temperature, and Wind Velocity between the Weddell Sea and the Ross Sea

1915 ◽  
Vol 35 ◽  
pp. 203-216
Author(s):  
R. C. Mossman
Keyword(s):  
South America ◽  
Wind Velocity ◽  
Air Temperature ◽  
Ross Sea ◽  
Barometric Pressure ◽  
Meteorological Conditions ◽  
Weddell Sea ◽  
The Other ◽  
The Subject ◽  
The One

In the course of a large inquiry on the inter-relations between the meteorological conditions in Antarctica and the Southern Ocean, on the one hand, and those prevailing in the southern continents, more especially South America, on the other, there has come to light an interesting see-saw between the barometric pressure, air temperature, and wind velocity in the Weddell and the Boss Seas. The above inquiry, which I hope to lay before this Society shortly, refers to the eight-year period 1902–09; and since the present paper deals with the years 1902, 1903, 1911, and 1912, I have thought it better to make it the subject of a separate communication. The positions of these stations and others where observations have been made are shown on the accompanying map, for which I am indebted to Dr H. R. Mill. The figures within the rings give the number of years covered by the records at the various places.

scholarly journals On the seasonal variation of atmospheric temperature in the British Isles and its relation to wind-direction, with a note on the effect of sea temperature on the seasonal variation of air temperature

1902 ◽  
Vol 69 (451-458) ◽  
pp. 61-85 ◽  
Keyword(s):  
Seasonal Variation ◽  
Air Temperature ◽  
Wind Direction ◽  
Atmospheric Temperature ◽  
British Isles ◽  
Sea Temperature ◽  
The Subject

The following paper is mainly concerned with the analysis of the seasonal variation of temperature of the British Islands into a series of simple harmonic curves. The variation of temperature is so irregular that the use of this method of analysis for the investigation of the subject may seem to he arbitrary and inappropriate, and a few words of introduction are accordingly necessary to indicate the circumstances under which this mode of dealing with the subject showed itself to be specially adapted for the purpose.

scholarly journals Factors affecting warmth comfort and stuffiness in domestic rooms

1947 ◽  
Vol 45 (4) ◽  
pp. 434-442
Author(s):  
K. W. Yarnold
Keyword(s):  
Air Temperature ◽  
Large Scale ◽  
Wave Length ◽  
Field Work ◽  
The Body ◽  
Equivalent Temperature ◽  
Factors Affecting ◽  
Two Factors ◽  
Striking Change ◽  
The Subject

One object of the investigation was to determine the ideal contributions to warmth comfort in small ‘domestic’ rooms of air heating and radiation. It was soon found that in rooms heated by fires, subjects usually complained of cold backs when the equivalent temperature was in the region of 60–65° F., the accepted standard for buildings heated by convection, and preferred equivalent temperatures above 70° F.Since large-scale trials, using many observers, were clearly necessary, the reliability of 5 min. test periods was studied; these short periods were proved reliable so long as the subject had previously been in a comfortable room for an hour or so.It was found necessary, in rooms heated by fires, to treat separately the side of the subject facing the fire and remote from it. The cooler side must be exposed to an equivalent temperature not much less than 65° F., while radiation falling on the warm side is to be regarded as a very desirable, but nonessential, bonus. These conclusions were confirmed by field work in the subjects' own homes.The eupatheoscope and globe thermometer were modified to enable conditions acting on the two sides of the body to be assessed separately.The extent to which radiation acting on the front of the body could compensate for a cold back to produce what was called ‘minimum comfort’ was also studied. It was shown that down to back equivalent temperatures of about 56° F. an increase of 2° in front equivalent temperature will compensate for a fall of 1° in back equivalent temperature, but below 56° F. compensation fails.The physical basis of sensations of stuffiness and freshness were also investigated. Throughout these experiments care was taken to ensure that the subjects were neither too hot nor too cold. In these conditions, only two factors appear to be important. First, the air temperature should be as low as possible. To obtain warmth comfort with a low air temperature some high temperature source of radiation is generally necessary. The peak wave-length of the radiation emitted by the fire is also of great importance, a striking change in the personal sensations occurring, for example, as the wave-length increases from 2 to 3μ. In general, those wavelengths which are absorbed in the outer layers of the skin cause sensations of stuffiness, and those which are not give rise to feelings of freshness. Peaks at 3, 4·1 and 4·7 μ should therefore be avoided in the design of gas and electric fires.

scholarly journals An evaluation of the impact of aerosol particles on weather forecasts from a biomass burning aerosol event over the Midwestern United States: observational-based analysis of surface temperature

2016 ◽  
Vol 16 (10) ◽  
pp. 6475-6494 ◽  
Author(s):  
Jianglong Zhang ◽  
Jeffrey S. Reid ◽  
Matthew Christensen ◽  
Angela Benedetti
Keyword(s):  
United States ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Cooling Efficiency ◽  
Surface Cooling ◽  
Near Surface ◽  
Smoke Aerosol ◽  
Weather Forecasts ◽  
Air Temperatures ◽  
Daily Changes

Abstract. A major continental-scale biomass burning smoke event from 28–30 June 2015, spanning central Canada through the eastern seaboard of the United States, resulted in unforecasted drops in daytime high surface temperatures on the order of 2–5  °C in the upper Midwest. This event, with strong smoke gradients and largely cloud-free conditions, provides a natural laboratory to study how aerosol radiative effects may influence numerical weather prediction (NWP) forecast outcomes. Here, we describe the nature of this smoke event and evaluate the differences in observed near-surface air temperatures between Bismarck (clear) and Grand Forks (overcast smoke), to evaluate to what degree solar radiation forcing from a smoke plume introduces daytime surface cooling, and how this affects model bias in forecasts and analyses. For this event, mid-visible (550 nm) smoke aerosol optical thickness (AOT, τ) reached values above 5. A direct surface cooling efficiency of −1.5 °C per unit AOT (at 550 nm, τ550) was found. A further analysis of European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP), United Kingdom Meteorological Office (UKMO) near-surface air temperature forecasts for up to 54 h as a function of Moderate Resolution Imaging Spectroradiometer (MODIS) Dark Target AOT data across more than 400 surface stations, also indicated the presence of the daytime aerosol direct cooling effect, but suggested a smaller aerosol direct surface cooling efficiency with magnitude on the order of −0.25 to −1.0 °C per unit τ550. In addition, using observations from the surface stations, uncertainties in near-surface air temperatures from ECMWF, NCEP, and UKMO model runs are estimated. This study further suggests that significant daily changes in τ550 above 1, at which the smoke-aerosol-induced direct surface cooling effect could be comparable in magnitude with model uncertainties, are rare events on a global scale. Thus, incorporating a more realistic smoke aerosol field into numerical models is currently less likely to significantly improve the accuracy of near-surface air temperature forecasts. However, regions such as eastern China, eastern Russia, India, and portions of the Saharan and Taklamakan deserts, where significant daily changes in AOTs are more frequent, are likely to benefit from including an accurate aerosol analysis into numerical weather forecasts.

Temperature Gradient of Concrete Pavement Slab Overlaid with Asphalt Surface Course

2000 ◽  
Vol 1730 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Tatsuo Nishizawa ◽  
Shigeru Shimeno ◽  
Akinori Komatsubara ◽  
Masashi Koyanagawa
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Stress ◽  
Temperature Gradient ◽  
Numerical Simulations ◽  
Structural Design ◽  
Concrete Slab ◽  
Concrete Pavement ◽  
Reduction Effect ◽  
The Relationship

In the structural design of composite pavement with a concrete pavement slab overlaid with an asphalt surface course, it is very important to estimate the temperature gradient in the concrete slab. An asphalt surface course reduces the temperature gradient in an underlaid concrete slab, resulting in the reduction of thermal stress of the concrete slab. This effect was investigated by temperature measurement in model pavements and by thermal conductivity analysis. Thermal properties were estimated by a backanalysis by using measured temperatures over 1 year. From the numerical simulations varying the thickness of asphalt surface and concrete slab, the relationship between the reduction effect and the asphalt thickness was derived as a function of the thickness of asphalt surface course, which can be used in the structural design of the composite pavement.

scholarly journals Long-term changes of weather stimuli based on the example of the southern part of Warsaw – Ursynów

2019 ◽  
Vol 28 (1) ◽  
pp. 25-34
Author(s):  
Katarzyna Rozbicka ◽  
Martyna Zawistowska
Keyword(s):  
Thermal Stress ◽  
Air Temperature ◽  
Significant Trend ◽  
Weather Station ◽  
Average Daily Temperature ◽  
Average Maximum ◽  
Long Term Changes ◽  
Frequency Changes ◽  
Thermal Stimuli

The aim of the work is to evaluate thermal sensations based on the average daily temperature of air and to determine thermal stimuli, using interdependent variability of air temperature (average, maximum and minimum). The data from the weather station Ursynów – SGGW was used for the analysis in the period 1961–2016. The analysis showed that with the highest frequency (74%) there are thermal sensations “saving” (“slightly cold”, “cool”, “warm”). In the case of thermal stimuli with the greatest frequency, changes from day to day were described as “neutral”, not exceeding 2°C . Based on the analysis of the long-term period trend of the number of days in the year, it can be stated an increase in the number of days with the thermal stress “very warm”, which is results from a positive statistically significant trend and also a decrease in number of days with thermal stimuli “sharp”.

scholarly journals Entropy Generation Analysis of Human Thermal Stress Responses

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Satish C. Boregowda ◽  
Robert E. Choate ◽  
Rodney Handy
Keyword(s):  
Thermal Stress ◽  
Relative Humidity ◽  
Air Temperature ◽  
Entropy Generation ◽  
Stress Responses ◽  
Military Medicine ◽  
Thermal Response ◽  
Response Data ◽  
Physiological Reaction ◽  
Human Thermal Model

The present study involves application of an open system entropy generation formulation to analyze human thermal stress responses. The time-series human thermal stress response data are obtained by conducting a simulation using a validated finite-element human thermal model (FEHTM). These simulated human thermal response data are used as an input to the entropy generation expression to obtain human entropy generation (HEG) values. The effects of variables such as air temperature, relative humidity, physical activity, and clothing on entropy generation are examined. A design of experiment (DOE) approach is utilized to study the interaction effects of air temperature and relative humidity on entropy generation. The study establishes the importance and utility of entropy generation as a holistic measure of human thermal physiological reaction to external and internal changes. This novel study has great potential for use in military medicine, rehabilitation, sports, and related applications.

RANCANG BANGUN FUEL PUMP PRESSURE TESTER PADA MOTOR INJEKSI

2019 ◽  
Vol 3 (1) ◽  
pp. 13-21
Author(s):  
Hamid Nasrullah ◽  
Ragil Saputra
Keyword(s):  
Literature Review ◽  
Subject Matter ◽  
Qualitative Method ◽  
Planning Process ◽  
Pressure Measurements ◽  
Fuel Pump ◽  
Construction Design ◽  
The Subject ◽  
Engine Failure ◽  
Pump Pressure

Pressurized fuel is fuel that is pumped by a fuel pump (fuel pump) from the fuel tank to the injector. Fuel pressure that is too low will greatly affect the performance of the engine and the risk of engine failure. Fuel pressure measurement aims to determine the performance of the fuel pump (fuel pump) is still able to work well or not.                     The method used is a qualitative method. The construction design starts from the planning process which includes making the concept of design, observation and processing of data so that it is found that the design is capable of reading fuel pressure from the fuel pump and is easy to use. To strengthen the results of the study, it is complemented by a literature review that has close relevance to the subject matter.                 Based on the results of testing that has been achieved from the entire process of making and testing the design of fuel pump pressure tester on injection motors, it can be concluded that the functional test in the last process shows that the tool can work well and is able to provide information on fuel pressure measurements from the fuel pump.

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