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Fundamentals
Published in Mike Tooley, Lloyd Dingle, Engineering Science, 2020
These molecular vibrations only cease when the temperature of the substance reaches absolute zero, i.e. −273.15°C. Thermodynamic temperature (in the SI system) is always measured in Kelvin and is known as absolute temperature.
Units and Dimensions
Published in C. Anandharamakrishnan, S. Padma Ishwarya, Essentials and Applications of Food Engineering, 2019
C. Anandharamakrishnan, S. Padma Ishwarya
kelvin (K): It is the unit of thermodynamic temperature and defined as 1/273.16 of the thermodynamic temperature of the triple point of water. Notable is that the thermodynamic temperature of water at its triple point is exactly 273.16 K.
Units and Significant Figures
Published in Patrick F. Dunn, Fundamentals of Sensors for Engineering and Science, 2019
The kelvin (K) is the SI base unit of temperature. The kelvin is based upon the triple point of pure water where pure water coexists in solid, liquid, and vapor states. This occurs at 273.16 K and 0.0060 atmospheres of pressure. Thus, a kelvin is 1/273.16 of the thermodynamic temperature of the triple point of pure water. Absolute zero, at which all molecular motion ceases, is 0 K.
Establishment of nitrous oxide (N2O) dynamics model based on ASM3 model during biological nitrogen removal via nitrification
Published in Environmental Technology, 2022
Ying Lv, Shoubin Zhang, Kang Xie, Guicai Liu, Liping Qiu, Yutian Liu, Yuanyuan Zhang
During the aeration phase, 20 ml of gaseous N2O was collected in an air bag, while 20 ml N2O into reactor were taken away using a syringe in the non-aeration phase. The gaseous N2O was analysed using gas chromatograph (FULI GC9790, China). This experiment uses N2O gas which concentration is 1.2 mg/L as standard gas. The determination of dissolved N2O was carried out by the headspace method [26] and the test apparatus is shown in Figure 3. The dissolved N2O concentration was measured by using the gas chromatograph (FULI GC9790, China). The resulting dissolved N2O concentration in activated sludge was calculated according to Henry’s law and Ideal Gas Law [27]: The [A (aq)] in the formula is the concentration of gas in the liquid phase (mg/L); KH is the Henry coefficient (mg/ (L = Pa)), and KH is constant at a given temperature. At 25℃, the Henry coefficient of N2O is KH = 2.47 × 10−7 mg/(L = Pa). PA is the partial pressure (PA) of N2O gas in the gas phase, which can be calculated through the Ideal Gas Law. In the Ideal Gas Law, P is the pressure of the ideal gas, V is the volume of the ideal gas, n is the amount of gaseous substances, and T is the thermodynamic temperature of the ideal gas. R is the ideal gas constant.
Novel operating band design schemes for high-contrast passive terahertz security screening systems
Published in Journal of Modern Optics, 2021
Zhang Yongfeng, Zhang Shufang, Sun Xiaoling
When and , where is the frequency and is the thermodynamic temperature, the inequality can be satisfied, where is the Boltzmann constant and is the Planck constant. Under these conditions, according to the Rayleigh-Jeans formula for blackbody radiation [23], and can be calculated from Equations (12) and (13), respectively, where is the body temperature, is the environmental temperature and is the speed of light.
Microfriction correction factor to the Stokes–Einstein equation for small molecules determined by NMR diffusion measurements and hydrodynamic modelling
Published in Molecular Physics, 2018
Petr Dvořák, Mária Šoltésová, Jan Lang
Due to the great technical progress in the area of pulsed field gradient NMR (PFG NMR) spectroscopy, it is now possible to measure routinely the translational self-diffusion coefficient of molecules in liquid in the absence of a chemical potential gradient. This has given us a tool for the determination of size or weight of molecules or supramolecular assemblies, which is of primary importance in many fields such as supramolecular chemistry, biochemistry, catalysis, material chemistry, polymer chemistry and physics etc. The translational self-diffusion coefficient is related to the molecular size through the well-known Stokes–Einstein relationship (1) [1,2]: where T is the thermodynamic temperature, η is the viscosity of the liquid and kB is the Boltzmann constant. Microfriction correction factor c is equal to 1 according to the original Stokes derivation [3]. Hydrodynamic radius rH can be viewed as a radius of a hypothetical hard sphere, which has the same diffusion coefficient as the studied particle. A lower limit for rH is the van der Waals radius rvdW. The equality rH = rvdW is valid only in the case of a compact molecule without any cavity inlet [4]. The upper bound of the hydrodynamic radius is given by the crystallographic radius rX-Ray, which can be obtained by dividing the volume of the crystallographic unit cell by the number of contained molecules while assuming a spherical shape for the molecule [4].