Rail Temperature Approximation and Heat Slow Order Best Practices

The railroad industry uses slow orders, sometimes referred to as speed restrictions, in areas where an elevated rail temperature is expected in order to minimize the risk and consequence of derailment caused by track buckling due to excessive rail temperature. Traditionally, rail temperature has been approximated by adding a constant offset, most often 30°F, to a peak ambient air temperature. When this approximated maximum rail temperature exceeds a given risk threshold, slow orders are usually issued for a predefined period of the day. This “one size fits all” approach, however, is not effective and suitable in all situations. On very warm days, the difference between rail temperature and ambient air temperature can exceed railroad-employed offsets and remain elevated for extended periods of time. A given temperature offset may be well suited for certain regions and track buckling risk-related rail temperature thresholds but less accurate for others. Almost 160,000 hours of rail temperature measurements collected in 2012 across the eastern United States by two Class I railroads and predicted ambient air temperatures based on the National Weather Service’s National Centers for Environmental Prediction (NCEP) data were analyzed using detection theory in order to establish optimal values of offsets between air and rail temperatures as well as times when slow orders should be in place based on geographical location and the track buckling risk rail temperature threshold. This paper presents the results of the analysis and describes an improved procedure to manage heat-related slow orders based on ambient air temperatures.

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EFFECTS OF LOW FLUCTUATING TEMPERATURES ON FARM ANIMALS: I. INFLUENCE OF AMBIENT AIR TEMPERATURE ON THE RESPIRATION RATE, HEART RATE, AND RECTAL TEMPERATURE OF LACTATING HOLSTEIN-FRIESIAN COWS

Canadian Journal of Animal Science ◽

10.4141/cjas58-002 ◽

1958 ◽

Vol 38 (1) ◽

pp. 10-22 ◽

Cited By ~ 9

Author(s):

M. A. MacDonald ◽

J. M. Bell

Keyword(s):

Heart Rate ◽

Respiration Rate ◽

Air Temperature ◽

Rectal Temperature ◽

Ambient Air ◽

Farm Animals ◽

Measurement Unit ◽

Ambient Air Temperature ◽

Air Temperatures ◽

Holstein Friesian

This report presents data on the effect of low fluctuating ambient air temperatures on the rectal temperature, heart rate, and respiration rate in lactating Holstein-Friesian cows.Daily minimum ambient air temperature (DMAAT) inside the uninsulated University of Saskatchewan loose-housing shed ranged from −5° F. to 38° F. As ambient temperature decreased, rectal temperature and heart rate increased, while respiration rate decreased. Levels of significance were 10, 9, and 1 per cent for regressions of rectal temperature, heart rate, and respiration rate, respectively, on DMAAT. Levels of significance were 7, 10, and 1 per cent for regressions of rectal temperature, heart rate, and respiration rate, respectively, on degree hours per day (d-h/day). Degree hours per day is a measurement unit developed by the authors and is based on time and difference in degrees from 50° F.Change in rectal temperature and heart rate were not significantly (P = >.05) correlated with either change in d-h/day or change in DMAAT. Change in respiration rate was significantly (P = <.02) and negatively correlated with change in d-h/day and significantly (P = <.06) and positively correlated with change in DMAAT.Heart rate, rectal temperature, and respiration rate were not significantly correlated with each other. However, change in respiration rate was positively correlated with change in rectal temperature (P = <.03).While the influence of low temperatures resulted in small changes in these physiological characteristics compared to those experienced elsewhere in high temperature zones, it cannot be concluded that lactating cows were entirely free of thermal stress at temperatures as low as 0° F.

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Season and ambient air temperature influence the distribution of mites (Proctophyllodes stylifer) across the wings of blue tits (Parus caeruleus)

Canadian Journal of Zoology ◽

10.1139/z00-068 ◽

2000 ◽

Vol 78 (8) ◽

pp. 1397-1407 ◽

Cited By ~ 9

Author(s):

P R Wiles ◽

J Cameron ◽

J M Behnke ◽

I R Hartley ◽

F S Gilbert ◽

...

Keyword(s):

Air Temperature ◽

Meteorological Data ◽

Ambient Air ◽

Parus Caeruleus ◽

Wing Feather ◽

Ambient Air Temperature ◽

Air Temperatures ◽

West Midlands ◽

Study Sites ◽

Blue Tits

Changes in the distribution of the wing-feather mite Proctophyllodes stylifer (Buckholz 1869) on the flight feathers of blue tits (Parus caeruleus) were studied throughout the seasons and in relation to ambient air temperature at three combinations of study sites (Lancashire, West Midlands, and South Midlands). We tested the hypotheses that the distribution of mites is influenced in part by season and ambient air temperature. In the winter months mites clustered predominantly on the tertiary feathers, whereas in late spring, summer, and autumn, mite-infestation scores were higher on the proximal primary and secondary feathers. Three approaches were employed to determine whether this seasonal redistribution of mites arose as a response to changes in microclimate, probably ambient air temperature, rather than to season per se. Firstly, meteorological data for the Lancashire study sites, and our own monitoring of the precise air temperature at the time of handling and inspection at the West Midlands study sites, enabled us to establish a link between distribution pattern and ambient temperature. Secondly, limited observations on the distribution of mites on birds recaptured when ambient air temperatures differed by 5°C or more between first and second nettings, one temperature being below 10°C and the other above, supported the idea that the change in distribution was associated with air temperature. Finally, the results of a small experiment in which heavily infested birds caught on a day when air temperatures ranged from 9 to 11°C were taken indoors and temporarily subjected to a higher ambient air temperature (20 min) prior to re-inspection and release also confirmed that mite movement was associated with the temperature of their environment. We conclude that the seasonal changes in distribution were driven by microclimatic changes, in part by temperature.

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RELATIONSHIP BETWEEN STREAM WATER TEMPERATURE AND AMBIENT AIR TEMPERATURE

Hydrology Research ◽

10.2166/nh.1972.0004 ◽

1972 ◽

Vol 3 (2) ◽

pp. 65-71 ◽

Cited By ~ 65

Author(s):

DANIEL A. CLUIS

Keyword(s):

Water Temperature ◽

Air Temperature ◽

Heat Budget ◽

Stream Water ◽

Ambient Air ◽

Ambient Air Temperature ◽

Air Temperatures ◽

Stochastic Fluctuations ◽

Alternative Approach ◽

Cyclic Variations

The water temperature of streams and rivers is required for various practical purposes and is frequently obtained by calculating the heat budget. This method is tedious and yields rather inaccurate values of the water temperature. This paper presents an alternative approach using cheap and simple means to measure air temperatures, which are believed to be a major factor controlling the water temperature. It is demonstrated that a useful separation can be made between the seasonal cyclic variations and the daily stochastic fluctuations of these temperatures.

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Photosynthesis of Sago Palm (Metroxylon sagu Rottb.) Seedling at Different Air Temperatures

10.20944/preprints201711.0121.v1 ◽

2017 ◽

Author(s):

Aidil Azhar ◽

Daigo Makihara ◽

Hitoshi Naito ◽

Hiroshi Ehara

Keyword(s):

Chlorophyll Content ◽

Air Temperature ◽

Photosynthetic Activity ◽

Leaf Gas Exchange ◽

Ambient Air ◽

Photosynthetic Parameters ◽

Sago Palm ◽

Ambient Air Temperature ◽

Air Temperatures ◽

Metroxylon Sagu

Photosynthetic activities of the sago palm (Metroxylon sagu Rottb.) were studied to find out its sensitivity to changes in ambient air temperature. The minimum ambient air temperature designed for the experiment was 25–29⁰C, while the higher end was 29–33⁰C. Several photosynthetic parameters were studied to support our analysis in sago photosynthetic activity, including diurnal leaf gas exchange, assimilation rate vs. CO2 concentration, leaf greenness, leaf chlorophyll content, and photosynthetic rate vs. irradiance. We found that sago palm photosynthetic activity tends to be more sensitive to minimum than to maximum ambient air temperature. The plants exposed to higher air temperatures had dark green leaf color associated with higher rates of diurnal photosynthesis, chlorophyll content, and rubisco limited photosynthetic activity. They also exhibited higher trend in optimum irradiance absorption level. Consequently, maximum light energy dissipation occurred at higher temperatures.

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THERMAL PERFORMANCE EVALUATION OF GREEN LIVING WALLS IN COMPOSITE CLIMATE

International Journal of Students Research in Technology & Management ◽

10.18510/ijsrtm.2020.842 ◽

2020 ◽

Vol 8 (4) ◽

pp. 8-16

Author(s):

Shruti Sharad Nagdeve ◽

Shweta Manchanda ◽

Anil Dewan

Keyword(s):

Relative Humidity ◽

Air Temperature ◽

Ambient Air ◽

Significant Drop ◽

Heat Gain ◽

Ambient Air Temperature ◽

High Solar Radiation ◽

The Difference ◽

Save Energy ◽

The Impact

Purpose of the study: Due to high solar radiation and extreme heat gain in composite climates, the envelope or the façade of the building becomes an essential part to modulate the heat transfer and temperature in the indoor environment. A passive sustainable approach to tackle heat gain is by adopting green living facades as the exterior skin. The objective of this research is to identify the potential of green living walls in modulating temperature and relative humidity in the composite climate of India. Methodology: This research is based on data collection in the form of a Case Study. The paper evaluates the difference of variation in temperature and relative humidity of two façade samples of the same building, one with a “green living facade” and one without it. Main Findings: The research aimed to justify that a green living facade may act as a passive strategy for composite climates. The result demonstrated that there is a significant temperature reduction between the ambient air temperature and indoor room temperature. The result also showed a notable change between ambient air temperature and the gap between the green living façade and the surface of the wall. Implications: Significant drop in indoor ambient temperature in composite climate may save energy for cooling or heating demands. Application of this study: This is a pilot study in order to carry out the main study for a similar application in order to categorize this as a passive sustainable façade strategy. Novelty/Originality of this study: The study is one of its kind attempt to investigate the impact of vertical green walls on thermal comfort in the composite climate of India.

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Treatment of a Municipal Leachate Under Multi-Variable Conditions

Water Quality Research Journal ◽

10.2166/wqrj.1982.011 ◽

1982 ◽

Vol 17 (1) ◽

pp. 135-148

Author(s):

P.T. Wong ◽

D.S. Mavinic

Keyword(s):

Air Temperature ◽

Nutrient Loading ◽

Ambient Air ◽

Removal Rates ◽

Ambient Air Temperature

Abstract The treatability of a municipal leachate (BOD5 = 8090 mg/L) was investigated, by aerobic biostabilization, at a nutrient loading of BOD5:N:P of 100:3.2:1.1. The first stage effluents were subsequently polished by lime-magnesium coagulation. The ranges of ambient air temperature and sludge age studied were 5° to 25°C and 5 to 20 days, respectively. In the biostabilization phase, a BOD5:N:P loading of 100:3.2:1.1 was found to be “adequate” for treatment. Organic and metal removals in the first stage units were excellent. Under all conditions investigated, except for the two units close to washout conditions (5-day sludge age units at 5° and 10°C), BOD5 and COD removals of at least 99.4 and 96.4 percent, respectively, were achieved. Similarly, removal rates for most of the metals monitored were greater than 90 percent. In general, the removal of residual contaminants was not enhanced significantly by the addition of magnesium in the lime-magnesium polishing step.

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Ambient Air Temperature Assisted Crystallization for Inorganic CsPbI2Br Perovskite Solar Cells

Molecules ◽

10.3390/molecules26113398 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3398

Author(s):

Yi Long ◽

Kun Liu ◽

Yongli Zhang ◽

Wenzhe Li

Keyword(s):

Solar Cells ◽

Air Temperature ◽

High Performance ◽

Defect Density ◽

Perovskite Solar Cells ◽

Ambient Air ◽

Dark Phase ◽

High Quality ◽

Ambient Air Temperature ◽

Air Atmosphere

Inorganic cesium lead halide perovskites, as alternative light absorbers for organic–inorganic hybrid perovskite solar cells, have attracted more and more attention due to their superb thermal stability for photovoltaic applications. However, the humid air instability of CsPbI2Br perovskite solar cells (PSCs) hinders their further development. The optoelectronic properties of CsPbI2Br films are closely related to the quality of films, so preparing high-quality perovskite films is crucial for fabricating high-performance PSCs. For the first time, we demonstrate that the regulation of ambient temperature of the dry air in the glovebox is able to control the growth of CsPbI2Br crystals and further optimize the morphology of CsPbI2Br film. Through controlling the ambient air temperature assisted crystallization, high-quality CsPbI2Br films are obtained, with advantages such as larger crystalline grains, negligible crystal boundaries, absence of pinholes, lower defect density, and faster carrier mobility. Accordingly, the PSCs based on as-prepared CsPbI2Br film achieve a power conversion efficiency of 15.5% (the maximum stabilized power output of 15.02%). Moreover, the optimized CsPbI2Br films show excellent robustness against moisture and oxygen and maintain the photovoltaic dark phase after 3 h aging in an air atmosphere at room temperature and 35% relative humidity (R.H.). In comparison, the pristine films are completely converted to the yellow phase in 1.5 h.

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Evaluation of the influence of ambient air temperature and air velocity on mortar cement durability using a forced convection solar dryer

International Journal of Building Pathology and Adaptation ◽

10.1108/ijbpa-08-2020-0069 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Younes Bahammou ◽

Mounir Kouhila ◽

Haytem Moussaoui ◽

Hamza Lamsyehe ◽

Zakaria Tagnamas ◽

...

Keyword(s):

Environmental Factors ◽

Forced Convection ◽

Air Temperature ◽

Building Materials ◽

Ambient Air ◽

Physical Significance ◽

Drying Process ◽

Air Velocity ◽

Content Type ◽

Ambient Air Temperature

PurposeThis work aims to study the hydrothermal behavior of mortar cement toward certain environmental factors (ambient air temperature and air velocity) based on its drying kinetics data. The objective is to provide a better understanding and controlling the stability of mortar structures, which integrate the sorption phenomenon, drying process, air pressure and intrinsic characteristics. This leads to predict the comportment of mortar structures in relation with main environmental factors and minimize the risk of cracking mortar structures at an early age.Design/methodology/approachThermokinetic study was carried out in natural and forced convection solar drying at three temperatures 20, 30 and 40°C and three air velocities (1, 3 and 5 m.s-1). The empirical and semiempirical models tested successfully describe the drying kinetics of mortar. These models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures.FindingsThe models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures. The average activation energy obtained expressed the temperature effect on the mortar diffusivity. The drying constant and the diffusion coefficient can be used to predict the influence of these environmental factors on the drying behavior of various building materials and therefore on their durability.Originality/valueEvaluation of the effect of several environmental factors and intrinsic characteristics of mortar structures on their durability.

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Direct Calculation of Thermodynamic Wet-Bulb Temperature as a Function of Pressure and Elevation

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-12-00191.1 ◽

2013 ◽

Vol 30 (8) ◽

pp. 1757-1765 ◽

Cited By ~ 10

Author(s):

Sayed-Hossein Sadeghi ◽

Troy R. Peters ◽

Douglas R. Cobos ◽

Henry W. Loescher ◽

Colin S. Campbell

Keyword(s):

Air Temperature ◽

Mean Absolute Error ◽

Direct Calculation ◽

Ambient Air ◽

Absolute Error ◽

Mean Square ◽

Air Temperatures ◽

Order Polynomial ◽

The Mean ◽

Very High

Abstract A simple analytical method was developed for directly calculating the thermodynamic wet-bulb temperature from air temperature and the vapor pressure (or relative humidity) at elevations up to 4500 m above MSL was developed. This methodology was based on the fact that the wet-bulb temperature can be closely approximated by a second-order polynomial in both the positive and negative ranges in ambient air temperature. The method in this study builds upon this understanding and provides results for the negative range of air temperatures (−17° to 0°C), so that the maximum observed error in this area is equal to or smaller than −0.17°C. For temperatures ≥0°C, wet-bulb temperature accuracy was ±0.65°C, and larger errors corresponded to very high temperatures (Ta ≥ 39°C) and/or very high or low relative humidities (5% < RH < 10% or RH > 98%). The mean absolute error and the root-mean-square error were 0.15° and 0.2°C, respectively.

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