scholarly journals Calculation of the temperature distribution in heated switch points

2021 ◽  
Author(s):  
Markus Schladitz ◽  
Robert Adam ◽  
Steffen Großmann
Keyword(s):  
Temperature Distribution ◽  
Winter Season ◽  
Field Tests ◽  
Weather Conditions ◽  
Calculation Model ◽  
Electrical Heating ◽  
Ambient Conditions ◽  
Switch Point ◽  
Set Up ◽  
Snow And Ice

Snow and ice can accumulate between the moveable parts of a switch point during the winter season. As a result he point cannot be switched anymore. In order to prevent failures and delays of trains, switch points are heated. Electrical heating rods shall ensure the melting of snow and ice in the critical areas of a point. Practical experiences have shown that this is not always possible. A calculation model for the heating of a point has to be set up in order to investigate the effectivity of switch point heating systems. Besides that, various ambient factors (such as ambient temperature, wind, precipitation) reduce the heating of the point. However, the extent of impact of the weather conditions on the heating remains to be investigated. Therefore, it is important to study their thermal influence and implement it into the calculation model. The Thermal Network Method (TNM) is suitable in this case. Initially the single main components of a switch point will be set up in separate networks. After a verification with experimental setups, the separate networks can be connected to each other. An experimental setup of an entire model point gives the opportunity to compare calculated and measured heating results without the influence of weather conditions. Finally, the ambient conditions can be implemented into the TNM model by performing field tests. The finished model can give high-resolution temperature information for different heating powers, ambient temperatures, wind velocities, rain and snowfall. According to the practical experience of various railway companies the temperature distribution is calculated for different parameter scenarios and subsequently evaluated regarding its effectivity to prevent failures.

Design and Construction of the World’s First Full-Scale Electrically Conductive Concrete Heated Airport Pavement System at a U.S. Airport

2018 ◽  
Vol 2672 (23) ◽  
pp. 82-94 ◽  
Author(s):  
Hesham Abdualla ◽  
Halil Ceylan ◽  
Sunghwan Kim ◽  
Mani Mina ◽  
Kristen S. Cetin ◽  
...  
Keyword(s):  
Winter Season ◽  
Weather Conditions ◽  
Full Scale ◽  
Sensor Data ◽  
Electrically Conductive ◽  
Sustainable Operations ◽  
Promising Alternative ◽  
Entire Area ◽  
Airport Pavement ◽  
Snow And Ice

Airport agencies spend millions of dollars to remove ice and snow from airport pavement surfaces to achieve accessible, safe, and sustainable operations during the winter. Electrically conductive concrete (ECON) based heated pavement system (HPS) has gained attention as a promising alternative technology for preventing snow and ice accumulation by maintaining pavement surface temperatures above the freezing point. The objective of this study was to demonstrate the world’s first full-scale ECON-based HPS at a U.S. airport. Two ECON slabs were designed and constructed in the General Aviation (GA) apron at the Des Moines International Airport (DSM), Iowa in 2016. Systematic design components were identified, and construction procedures were developed and implemented for ECON-based HPS. Using collected sensor data, the performance of the constructed and remotely-operated ECON slabs was evaluated under real weather conditions at DSM in the 2016–2017 winter season. The results demonstrate that ECON-based HPS have promising deicing and anti-icing capacities, promising to provide uniform heat distribution and prevent snow and ice accumulations on the entire area of application under various winter weather conditions, including extreme cold weather (i.e., arctic blasts).

Computational Analysis to Design Energy Efficient Built Environments

2012 ◽  
Author(s):  
Guy Abou-Nassar ◽  
Zahed Siddique ◽  
Lee Fithian
Keyword(s):  
Natural Ventilation ◽  
Stokes Equations ◽  
Weather Conditions ◽  
Navier Stokes ◽  
Ambient Conditions ◽  
Navier Stokes Equations ◽  
Double Skin ◽  
Set Up ◽  
Shading Devices ◽  
Volume Method

Double skin facades (DSF) provide a means of enhancing the energy saving capabilities of buildings. By being able to respond dynamically to changing ambient conditions using natural ventilation, shading devices, and/or thermal insulation devices or strategies, DSFs are being incorporated into modern architecture and even retrofitted in some older structures to reduce the energy required to balance the load input into the building. Utilizing a general building model and weather conditions and integrating various designs for DSFs, a comparative study can be made to support or oppose the different designs changes being made. The analysis of the set-up will be performed by Fluent, a computational fluid dynamics (CFD) software. Fluent will solve for the Navier-Stokes equations and turbulent flow using the finite volume method. These results show that the energy necessary to power the HVAC system decreases with certain configurations.

Performance Assessment of Cogeneration Systems for Industrial District Applications

2007 ◽  
Author(s):  
Stefano Campanari ◽  
Paolo Chiesa ◽  
Paolo Silva
Keyword(s):  
Economic Analysis ◽  
Gas Turbine ◽  
Energy Savings ◽  
Combustion Engine ◽  
Weather Conditions ◽  
Electrical Heating ◽  
Test Case ◽  
Ambient Conditions ◽  
Fuel Prices ◽  
Cogeneration System

This paper discusses the development and testing of an optimization tool for the energy and economic analysis of cogeneration systems and its application to industrial districts composed by different factories (with electrical, heating and in some cases cooling demand), with time-variable loads and several day-types profiles. The discussion compares three cogeneration systems, respectively based on: (i) a simple cycle gas turbine or (ii) a recuperative cycle gas turbine, both with heat recovery and an absorption chiller, and (iii) an internal combustion engine with electrical chiller units. Test case specifications also include tariff, regulatory and weather conditions, provided that performance of the main components are corrected as a function of load and ambient conditions. The model demonstrates to be really effective in defining the best operating strategy for each cogeneration system; detailed results are presented, in terms of annual energy balances, energy savings compared to separate generation systems (grid losses as well as heat distribution losses are taken into account) and economic analysis. A final parametric analysis is carried out to show the influence on the final results of different assumptions on the combination of fuel prices and electricity tariffs.

Investigating the effect of wearing glasses on the human eyes' temperature distribution in different ambient conditions

2021 ◽  
pp. 102971
Author(s):  
Kavan Zarei ◽  
Mansour Lahonian ◽  
Saman Aminian ◽  
Sasan Saedi ◽  
Mehdi Ashjaee
Keyword(s):  
Temperature Distribution ◽  
Ambient Conditions ◽  
Human Eyes

scholarly journals Prediction of Pest Insect Appearance Using Sensors and Machine Learning

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4846
Author(s):  
Dušan Marković ◽  
Dejan Vujičić ◽  
Snežana Tanasković ◽  
Borislav Đorđević ◽  
Siniša Ranđić ◽  
...  
Keyword(s):  
Machine Learning ◽  
Relative Humidity ◽  
Weather Conditions ◽  
Daily Basis ◽  
Machine Learning Algorithms ◽  
Lower Percentage ◽  
Timely Manner ◽  
Proposed Model ◽  
Set Up ◽  
Accuracy Of Prediction

The appearance of pest insects can lead to a loss in yield if farmers do not respond in a timely manner to suppress their spread. Occurrences and numbers of insects can be monitored through insect traps, which include their permanent touring and checking of their condition. Another more efficient way is to set up sensor devices with a camera at the traps that will photograph the traps and forward the images to the Internet, where the pest insect’s appearance will be predicted by image analysis. Weather conditions, temperature and relative humidity are the parameters that affect the appearance of some pests, such as Helicoverpa armigera. This paper presents a model of machine learning that can predict the appearance of insects during a season on a daily basis, taking into account the air temperature and relative humidity. Several machine learning algorithms for classification were applied and their accuracy for the prediction of insect occurrence was presented (up to 76.5%). Since the data used for testing were given in chronological order according to the days when the measurement was performed, the existing model was expanded to take into account the periods of three and five days. The extended method showed better accuracy of prediction and a lower percentage of false detections. In the case of a period of five days, the accuracy of the affected detections was 86.3%, while the percentage of false detections was 11%. The proposed model of machine learning can help farmers to detect the occurrence of pests and save the time and resources needed to check the fields.

Study on a Numerical Model of “Rainfall-Runoff” Process Combined with Snowmelt

2012 ◽  
Vol 518-523 ◽  
pp. 4273-4277
Author(s):  
Huang Jinbai ◽  
Wang Bin ◽  
Hinokidani Osamu ◽  
Kajikawa Yuki
Keyword(s):  
Numerical Method ◽  
Wave Theory ◽  
Large Error ◽  
Calculation Model ◽  
Surface Flow ◽  
Snow Melt ◽  
Rainfall Runoff ◽  
Surface Water Resources ◽  
Permissible Range ◽  
Set Up

In order to achieve the accurate calculation of “rainfall-runoff” process combined with snowmelt and to provide a useful numerical method for estimating surface water resources in a basin, a runoff numerical calculation model of “rainfall-runoff” process combined with snowmelt was developed for a distributive hydrological model. Numerical method on “Rainfall-runoff” process was set up by applying kinematic wave theory, and calculations on snowmelt were made using energy budget method. Validity of the model was verified through numerical simulation of the observed surface flow. Results of the error analysis indicated that a large error existed between the numerical results and the observed ones without considering snowmelt whereas the error was at the permissible range of criterion (< 3 %) by considering snowmelt. The results showed that the snowmelt calculation should be considered at snow melt area when performing the runoff calculation.

Analysis of the Ventilation Effects on Radon-222 Exhalation in a Dead-End Tunnel

2015 ◽  
Vol 713-715 ◽  
pp. 304-313
Author(s):  
Shu Guang Wang ◽  
Wei Yang ◽  
Qing Chen ◽  
Jian Hua Chen ◽  
Cong Han
Keyword(s):  
High Temperature ◽  
Ambient Temperature ◽  
Natural Ventilation ◽  
Weather Conditions ◽  
Calculation Model ◽  
Radon Exhalation Rate ◽  
Exhalation Rate ◽  
Radon Exhalation ◽  
Exhaust Ventilation ◽  
Dead End

The regularity of radon exhalation rate in the over-broken granite tunnel is susceptible to weather conditions and ventilation styles. Based on the calculation model of radon exhalation in tunnel, some experiments have been carried out to analyze the variations of radon exhalation in cases of natural ventilation, blowing ventilation and exhaust ventilation separately. The results show that there is a linear relation between the radon exhalation and the natural ventilation quantity, and also between the radon exhalation and the ambient temperature; the radon exhalation in the case of exhaust ventilation is 63% higher than that in the blowing case under the condition of the same ventilation quantity and ambient temperature. Therefore, it is suggested that operation in the tunnel in high temperature be avoided in summer, and the blowing ventilation be adopted as an effective way for ventilation.

Environmental Demands Associated With Community Mobility in Older Adults With and Without Mobility Disabilities

2002 ◽  
Vol 82 (7) ◽  
pp. 670-681 ◽  
Author(s):  
Anne Shumway-Cook ◽  
Aftab E Patla ◽  
Anita Stewart ◽  
Luigi Ferrucci ◽  
Marcia A Ciol ◽  
...  
Keyword(s):  
Older Adults ◽  
Weather Conditions ◽  
Grocery Store ◽  
Fisher Exact Test ◽  
Ambient Conditions ◽  
Mobility Disability ◽  
Exact Test ◽  
Mobility Function ◽  
Community Mobility ◽  
Trip Frequency

Abstract Background and Purpose. In this study, the influence of 8 dimensions of the physical environment on mobility in older adults with and without mobility disability was measured. This was done in order to identify environmental factors that contribute to mobility disability. Subjects. Subjects were 36 older adults (≥70 years of age) who were recruited from 2 geographic sites (Seattle, Wash, and Waterloo, Ontario, Canada) and were grouped according to level of mobility function (physically able [ability to walk ½ mile (0.8 km) or climb stairs without assistance], physically disabled). Methods. Subjects were observed and videotaped during 3 trips into the community (trip to grocery store, physician visit, recreational trip). Frequency of encounters with environmental features within each of the 8 dimensions was recorded. Differences in baseline characteristics and environmental encounters were analyzed using an analysis of variance or the Fisher exact test, as appropriate. Results. Mobility disability among older adults was not associated with a uniform decrease in encounters with environmental challenges across all dimensions. Environmental dimensions that differed between subjects who were physically able and those with physical disability included temporal factors, physical load, terrain, and postural transition. Dimensions that were not different included distance, density, ambient conditions (eg, light levels and weather conditions), and attentional demands. Discussion and Conclusion. Understanding the relationship of the environment to mobility is crucial to both prevention and rehabilitation of mobility disability in older adults. Among older adults, certain dimensions of the environment may disable community mobility more than others.

scholarly journals Measurements in Solid Propellant Plumes at Ambient Conditions

2011 ◽  
Author(s):  
Jonathan L. Height ◽  
Burl A. Donaldson ◽  
Walter Gill ◽  
Christian G. Parigger
Keyword(s):  
Temperature Distribution ◽  
Solid Propellant ◽  
Aluminum Particle ◽  
Burning Surface ◽  
Ambient Conditions ◽  
Aluminum Particles ◽  
Open Atmosphere ◽  
Particle Ignition ◽  
Accident Scenarios ◽  
Color Pyrometer

The study of aluminum particle ignition in an open atmosphere propellant burn is of particular interest when considering accident scenarios for rockets carrying high-value payloads. This study investigates the temperature of an open atmosphere Atlas V solid propellant burn as a function of height from the burning surface. Two instruments were used to infer this temperature: a two-color pyrometer and a spectrometer. The spectra were fitted to a model of energy states for aluminum monoxide. The temperature which provided the best match between the model and data was taken as the reaction temperature. Emissions above 30 inches from the surface of the propellant were not sufficiently strong for data reduction, perhaps obscured by the alumina smoke cloud. The temperature distribution in the plume increased slightly with distance from the burning surface, presumably indicating the delay in ignition and heat release from the larger aluminum particles in the propellant. The pyrometer and spectrometer results were found to be in excellent agreement indicating plume temperatures in the range of 2300K to 3000K.

scholarly journals Characterization of interferences to in situ observations of <i>δ</i><sup>13</sup>CH<sub>4</sub> and C<sub>2</sub>H<sub>6</sub> when using a cavity ring-down spectrometer at industrial sites

2017 ◽  
Vol 10 (6) ◽  
pp. 2077-2091 ◽  
Author(s):  
Sabina Assan ◽  
Alexia Baudic ◽  
Ali Guemri ◽  
Philippe Ciais ◽  
Valerie Gros ◽  
...  
Keyword(s):  
Near Infrared ◽  
Field Tests ◽  
Isotopic Signature ◽  
Ambient Conditions ◽  
Industrial Sites ◽  
Source Determination ◽  
Infrared Spectral ◽  
The Subject

Abstract. Due to increased demand for an understanding of CH4 emissions from industrial sites, the subject of cross sensitivities caused by absorption from multiple gases on δ13CH4 and C2H6 measured in the near-infrared spectral domain using CRDS has become increasingly important. Extensive laboratory tests are presented here, which characterize these cross sensitivities and propose corrections for the biases they induce. We found methane isotopic measurements to be subject to interference from elevated C2H6 concentrations resulting in heavier δ13CH4 by +23.5 ‰ per ppm C2H6 ∕ ppm CH4. Measured C2H6 is subject to absorption interference from a number of other trace gases, predominantly H2O (with an average linear sensitivity of 0.9 ppm C2H6 per  % H2O in ambient conditions). Yet, this sensitivity was found to be discontinuous with a strong hysteresis effect and we suggest removing H2O from gas samples prior to analysis. The C2H6 calibration factor was calculated using a GC and measured as 0.5 (confirmed up to 5 ppm C2H6). Field tests at a natural gas compressor station demonstrated that the presence of C2H6 in gas emissions at an average level of 0.3 ppm shifted the isotopic signature by 2.5 ‰, whilst after calibration we find that the average C2H6 : CH4 ratio shifts by +0.06. These results indicate that, when using such a CRDS instrument in conditions of elevated C2H6 for CH4 source determination, it is imperative to account for the biases discussed within this study.

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