About wear and average surface temperature of copper or steel contacts at sliding current collection

2015 ◽  
Author(s):  
V. V. Fadin ◽  
M. I. Aleutdinova ◽  
V. Ye. Rubtsov
Keyword(s):  
Surface Temperature ◽  
Average Surface ◽  
Current Collection ◽  
Average Surface Temperature

An Integrated Model of Global Warming and Policy Making

2011 ◽  
Author(s):  
Zheming Zhang ◽  
Ramesh Agarwal
Keyword(s):  
Global Warming ◽  
Surface Temperature ◽  
Co2 Emissions ◽  
General Circulation ◽  
Co2 Concentration ◽  
Integrated Model ◽  
Co2 Mitigation ◽  
Average Surface ◽  
Global Average ◽  
Average Surface Temperature

This paper describes a simple integrated model of global warming due to anthropogenic CO2 emissions, which can help the policy makers in considering various CO2 mitigation strategies. First, the constant airborne fraction model is generalized to establish relationship between CO2 emissions and CO2 concentration in the atmosphere which is then used to determine the global average surface temperature using the Oglesby and Saltzman’s general circulation model. Using these simple relationships, the forecast for CO2 emissions, CO2 concentration and average global surface temperature is made for years 2030 and 2050 under Business as Usual (BAU) scenario. In order to achieve an acceptable target increase in global average surface temperature, several simple CO2 mitigation approaches, proposed by Socolow and Lam, are included in the integrated model.

On the strongly negative cloud feedback over the satellite period implied by observational SST reconstructions

2021 ◽  
Author(s):  
Stephan Fueglistaler ◽  
Levi Silvers
Keyword(s):  
Surface Temperature ◽  
General Circulation ◽  
Deep Convection ◽  
Historical Period ◽  
Surface Temperature Change ◽  
Average Surface ◽  
Global Average ◽  
Coupled Gcm ◽  
Average Surface Temperature ◽  
Second Mode

<p>Clouds strongly modulate Earth's radiative budget, and uncertainties in numerical model simulations of the global cloud field contribute substantially to uncertainties in future warming. In coupled atmosphere-ocean General Circulation Model (GCM) simulations, the global cloud field and its radiative effect are well correlated with global average surface temperature. However, GCM simulations with prescribed Sea Surface Temperatures (SSTs) from observational SST reconstructions over the historical period show time-varying relationships between the cloud field and average surface temperature (known as the "pattern effect"). We show that CERES/EBAF observational data confirms the presence of a second mode (in addition to mean SST) in particular in low cloud amount (and correspondingly SWCRE) that is consistent with variations in tropical atmospheric stability in ERA-Interim reanalysis data. This second mode in observations is tied to ENSO, and evolves in quadrature to ENSO indexes. It arises from differences in surface temperature change between regions of tropical deep convection and the tropical (or global) average. In contrast to the multidecadal trends over the full historical period, trends in this second mode since the year 2000 are small. The PCMDI/AMIPII SSTs recommended for CMIP6 stand out as having the largest trend over the full historical period. Different SST reconstructions agree on a trend over the satellite period - specifically the 1980s-90s - that is much larger than what coupled GCM simulations show: In forced coupled GCM simulations the regions of deep convection warm order 10% more than the tropical average, whereas over the satellite period the amplification is order +50%  in the AMIP simulations and in estimates using rainfall observations to identify regions of deep convection.</p>

An Analysis of Various Cooling Liquids in a Two-Cylinder Single-Stage Piston Hybrid Power Machine with Fluid Flow Due to Vacuum at Suction Based on Experimental Results

2020 ◽  
pp. 40-49
Author(s):  
V.E. Shcherba ◽  
G.S. Averyanov ◽  
S.A. Korneev ◽  
S.V. Korneev ◽  
A.Y. Ovsyannikov ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Surface Temperature ◽  
Distilled Water ◽  
Average Surface ◽  
Working Chamber ◽  
Hybrid Power ◽  
Average Surface Temperature ◽  
Transmission Oil ◽  
Power Machine ◽  
Hybrid Power Machine

This paper examines the use of various types of cooling liquids in a two-cylinder single-stage piston hybrid power machine with fluid flow due to vacuum at suction. Liquids with various basic thermal properties were used as working fluids: distilled water, antifreeze, and transmission oil. Specific heat capacities and dynamic viscosities of these liquids differed from 2 to 10 times. The experimental studies showed that the greatest cooling effect on the cylinder-piston group was observed when using distilled water, and the least — when using transmission oil. The average surface temperature of the working chamber when cooled with water was minimal in the range of 330–340 K. The average surface temperature of the working chamber when cooled with transmission oil was maximum and ranged from 345 to 355 K, i. e. it was about 15 K higher than when cooled with water. The average surface temperature of the working chamber when cooled with antifreeze occupied an intermediate position between the average temperatures of the working chamber when cooled with water and that with transmission oil and was in the range of 335–345 K, i. e. about 5 K higher than when cooled with water.

scholarly journals Assessing the efficiency of green roof technology: A case study of Masjid Kota Iskandar, Nusajaya, Johor

2018 ◽  
Vol 250 ◽  
pp. 06011
Author(s):  
Muhamad Hanafi Rahmat ◽  
Muhd Hariz Mohkatar ◽  
Izudinshah Abd Wahab ◽  
Nur Nasuha Abd Salam ◽  
Hazri Abdul Aziz ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Surface Temperature ◽  
Engineering Design ◽  
Green Roof ◽  
Infrared Thermometer ◽  
Average Surface ◽  
Minimum Surface ◽  
Average Surface Temperature ◽  
Hot Climate

Green roof is a system that had been identified as a medium that is able to reduce the thermal temperature of a building. It is an efficient way of reducing heat especially for hot climate countries like Malaysia. This study was conducted to assess the ability and the effectiveness of green roof in controlling the temperature of a building and also to make a comparison of its performance with the conventional roof. The study was conducted at the Masjid Kota Iskandar, Nusajaya, Johor. For this case study, Infrared Thermometer and 4 in 1 Meter Kit were used to record the temperature (maximum and minimum) during the day on the surface of the green roof and conventional roof as well as its relative humidity. The experiments were conducted during sunny days from 8.00 am to 6.00 pm at an interval of two hours on two different dates which were 18th March 2017 and 4th April 2017. Few locations for the data to be collected were plotted on the surface of both roofs and the readings of maximum and minimum surface roof temperatures were recorded for comparison. Based on the research that had been carried out, it can be concluded that the usage of green roof was able to reduce the average surface temperature in the range of 3.6°C –11.1°C as compared to the conventional roof. This result had proven that there was a decrease in temperature for the green roof as compared to the conventional roof. It had shown that the usage of the green roof in a building was an efficient way of reducing building temperature and also an effective way to achieve sustainability in architecture and engineering design.

Transient Natural Convection From Vertical Elements

1961 ◽  
Vol 83 (1) ◽  
pp. 61-70 ◽  
Author(s):  
B. Gebhart
Keyword(s):  
Natural Convection ◽  
Prandtl Number ◽  
Surface Temperature ◽  
Extreme Case ◽  
Transient Behavior ◽  
Thermal Capacity ◽  
Average Surface ◽  
Transient Natural Convection ◽  
Average Surface Temperature ◽  
Prandtl Numbers

The transient natural-convection process is analyzed using an integral method of analysis. Differential equations are derived which relate average surface temperature and time for either heating or cooling for vertical elements having arbitrary thermal capacity. The equations are applicable to laminar flow for all fluids. The coefficients are Prandtl number dependent and are estimated for Prandtl numbers in the range 0.01 to 1000. A solution of the equations is presented for the extreme case of a vertical plate of negligible thermal capacity subjected to a step in flux at its surface. Fluids having Prandtl numbers of 0.01, 0.1, 0.72, 1.0, 5, 10, 100, and 1000 are considered. The results, in terms of generalized variables, are practically independent of Prandtl number. Simple one-dimensional transient behavior is followed for approximately 20 per cent of the transient with a subsequent quick approach to the asymptotic value. The results show no substantial overshoot of the average surface temperature. It is doubted that significant temperature overshoot actually occurs for vertical surfaces even for a step in flux.

Evaluation of synchronizer loading parameters and their ability to predict failure

2017 ◽  
Vol 232 (9) ◽  
pp. 1093-1104 ◽  
Author(s):  
Daniel Häggström ◽  
Ulf Sellgren ◽  
Stefan Björklund
Keyword(s):  
Kinetic Energy ◽  
Service Life ◽  
Surface Temperature ◽  
Temperature Increase ◽  
Good Accuracy ◽  
Test Rig ◽  
Average Surface ◽  
Average Surface Temperature ◽  
Focal Surface ◽  
Short Service Life

Molybdenum coated gearbox synchronizers are tested in a μ-comp test rig under varying loading conditions until failure. Four different parameters used to describe the thermomechanical load are evaluated just before failure to compare their ability to predict failure. The parameters evaluated are the synchronized kinetic energy, the synchronization power, and the focal as well as the average surface temperature increase. The focal surface temperature increase as well as the average surface temperature increase is found to predict failure with relatively good accuracy. It is shown that there exists a threshold which divides the synchronizer into either a very long or a very short service life. Additionally, a method to determine the average surface temperature in the gearbox management system is proposed.

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