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Air pollution modelling
Published in Abhishek Tiwary, Ian Williams, Air Pollution, 2018
The adiabatic lapse rates describe the temperature changes expected in a parcel of air when it is displaced vertically. This is not usually the same as the vertical temperature profile of the air, as would be measured, for example, by recording the temperature transmitted by a sounding balloon as it rose through the atmosphere. This environmental lapse rate (ELR) is the vertical variation, or profile, of air temperature with height that exists at any particular time and place. It may be equal to the adiabatic lapse rate over at least part of the height range of interest (up to, say, 1 km for pollutant dispersion), but it may be substantially different. The local balance between the two lapse rates gives an insight into the concept known as atmospheric stability, which in essence is a measure of the atmosphere’s tendency to encourage or deter vertical movement of air, that is, exchange processes – stable air tends to resist vertical air movement, and vice versa.
Physical Foundation of Interior Ballistics
Published in Donald E. Carlucci, Sidney S. Jacobson, Ballistics, 2018
Donald E. Carlucci, Sidney S. Jacobson
One important parameter in determining the amount of energy transferred to the projectile is the temperature of the product gases. As you can see from our example, an increase in the temperature of the product gases will result in a decrease in the projectile velocity because Hp goes up. Typically, we can assume the product gases exit at a temperature between 0.6T0 and 0.7T0, where T0 is the adiabatic flame temperature of the product gases [7]. The adiabatic flame temperature of a gas is the temperature that is achieved if the gases burn to completion in the absence of any heat transfer or work being performed [1]. The calculation of the adiabatic flame temperature is relatively straightforward but requires iteration. This is beyond the scope of this chapter, but the reader is referred to the references at the end of this chapter for a complete description of the procedure. In addition, there are several commercially available codes (including some that come with the purchase of textbooks now, for instance, the book by Cengel and Boles [13]). To achieve our objectives, the temperature of the reaction products will always be given.
A Physical and Chemical Equilibrium
Published in Danny D. Reible, Fundamentals of Environmental Engineering, 2017
The approach employed in Example 4.6 can be used to estimate the adiabatic flame temperature of a combustion reaction. An adiabatic process is one in which no heat is added or removed from the system. The adiabatic flame temperature is thus the temperature that results if all of the heat generated by the combustion is absorbed by the combustion product gases. For a hydrocarbon fuel, the primary products are carbon dioxide and water vapor, [f air is employed as the source of oxygen, nitrogen is an unavoidable diluent of the products. Since the heat generated by the reaction does not change whether air or pure oxygen is used as the oxygen source, the use of air results in a reduced adiabatic flame temperature. Excess oxygen or air also is often used to ensure good combustion without the formation of such things as soot, which are products of incomplete combustion (PICs). The extra oxygen and/or air also serves to dilute the product gases and lowers their adiabatic flame temperature.
Design and Optimization of 4-Bit Array Multiplier with Adiabatic Logic Using 65 nm CMOS Technologies
Published in IETE Journal of Research, 2023
Divya Sharma, Amrita Rai, Sunita Debbarma, Om Prakash, Mukesh Kumar Ojha, Vijay Nath
In the field of DSP (Digital Signal Processing), the multiplier is used as most circuit for any computational architecture like CPU, arithmetic logical computation, and filter implementation. Power dissipation is a very important factor for this. To avoid power dissipation, various techniques are there in which adiabatic one of them. The term adiabatic refers to the thermodynamic process that exchanges no heat with the environment. In adiabatic logic, we did not give a constant supply VDD instead of a constant supply we give a pulse power supply to conserve the energy. In CMOS logic, as we use constant supply voltage then power is dissipated in discharging phase through the pull-down network but in adiabatic logic, as we used pulse power supply then in discharging phase the stored energy is feedback to its supply, so energy dissipation is reduced. Reducing the power subthreshold operation has become a promising option because of scaling down the applied voltage below the subthreshold voltage.
Creep life prediction for a nickel-based single crystal turbine blade
Published in Mechanics of Advanced Materials and Structures, 2022
Zhen Li, Zhixun Wen, Haiqing Pei, Xiaowei Yue, Pu Wang, Changsheng Ai, Zhufeng Yue
As is known to all, the isentropic process is also called the reversible adiabatic process. The adiabatic process is a thermal process in which the gas does not exchange heat with the external environment. When the process is proceeding very fast, the working fluid are too late to exchange heat with the external environment or the exchange of heat is very little. It can be approximately regarded as an adiabatic process. The compression process of the gas in the compressor of the turbine engine and the expansion process in the turbine as well as the exhaust nozzle can be regarded as an adiabatic process. The inlet boundary condition is a pressure inlet. The gas inlet angle, total pressure distortion intensity, and total temperature are shown in Figure 8. Among them, the definition of total pressure distortion intensity is shown in equation (10).
Short-Term Assessment of Radiological Impact and Potential Risk to Workers and Public from Argonaut Nuclear Reactor Accidental Release
Published in Nuclear Technology, 2021
Paula C. Souza, André S. Aguiar, Adino Heimlich, Celso M. F. Lapa, Fernando Lamego
The atmosphere stability is related to the change of temperature with height, called lapse rate, which is related to turbulence induced by thermal gradient. If a parcel of dry air moves adiabatically, its temperature will decrease by 0.98°C for each 100-m rise (i.e., ΔT = −0.98°C‧100 m−1). If the lapse rate is smaller than the dry adiabatic lapse rate, the shifted parcel will become warmer than its outskirts and will keep rising vertically, causing atmospheric unstable conditions (ΔT ≤ −1.5°C‧100 m−1). Otherwise, if it is greater than the dry adiabatic lapse rate, the parcel will become cooler than its environment and come down to its starting position, leading to atmospheric stability (ΔT > −0.5°C‧100 m−1). The atmosphere is neutral (−1.5°C < ΔT ≤ −0.5°C‧100 m−1) when the lapse rate is equal to the dry adiabatic lapse rate.6