China
Africa
Explore chapters and articles related to this topic
Macrophyte-Mediated Oxygen Transfer in Wetlands: Transport Mechanisms and Rates
Published in Gerald A. Moshiri, Constructed Wetlands for Water Quality Improvement, 2020
Thermal transpiration is the movement of gas through a porous partition when there is a gradient in temperature across the partition. Thermal transpiration leads to a pressure gradient across the partition, the pressure being higher on the warmer side. Humidity-induced pressurization is related to pressure differentials induced by differences in water vapor pressure across a porous partition. The result of humidity-induced pressurization is that the total pressure will be higher on the more humid side of the partition. In the case of water lilies, the pressurization is greatest in the youngest leaves. The slightly increased pressures in young leaves are released through the leaf petioles, the buried rhizome, and back to the atmosphere through petioles and leaf blades of older leaves (Figure 3). Pressurized ventilation of the root system is not restricted to water lilies and species with a similar morphology. The aeration of the rhizomes of the common reed (Phragmites australis) is significantly enhanced by a similar convective throughflow mechanism.17,18 Furthermore, recent investigations have shown that internal pressurization and convective throughflow driven by gradients in temperature and water vapor pressure seem to be common attributes of a wide range of wetland plants, including species with cylindrical and linear leaves (e.g., Typha, Schoenoplectus, Eleocharis).19
Cross sections for electron collision with pyridine [C5H5N] molecule
Published in Molecular Physics, 2019
Czesław Szmytkowski, Sylwia Stefanowska, Natalia Tańska, Bożena Żywicka, Elżbieta Ptasińska-Denga, Paweł Możejko
The quantities necessary for TCS derivation are taken directly in the present experiment and therefore cross section values reported in this work are given in absolute units, without any normalisation procedure. L was taken equal the distance (30.5 mm) between entrance and exit apertures of the reaction cell, while the target density value, n, is evaluated from the ideal gas formula corrected for the thermal transpiration effect [33] where means the pressure of the vapour-target in the cell as measured by a capacitance manometer and k denotes the Boltzmann constant; is the temperature of the target cell determined using a thermocouple; K is the temperature at which the manometer head is held.
Performance analysis of a novel thermal transpiration vacuum cooling system
Published in International Journal of Green Energy, 2022
Wenjie Zhang, Wei Lu, Botao Wang
The thermal transpiration-based pump/compressor (an extention of the Knudsen pump/compressor) possesses the feature of no moving parts and can directly be powered by heat. With the deep investigation on the Knudsen pump/compressor (Pham-Van-Diep et al. 1995; Zhang et al. 2019), it is gradually attractive in the field of refrigeration. Muthuvijayan et al. (2017) proposed a Knudsen compressor-based Joule-Thomson Cryocooler for the thermal management of spacecraft, which was further confirmed to be feasible by their experiment. Kugimoto et al. (2018; 2019) proposed a heat pump system using water as the working fluid and Knudsen compressor as the main component and simultaneously established the experimental device and corresponding mathematic model to study the operation characteristics of the proposed system. Lu et al. (2014a) and Lu et al. (2015) and Yang et al. (2015) put forward several types of vapor compression refrigeration systems with features of conventional mechanical compressor replaced with Knudsen compressor in essence. Then, the mathematical model of performance analysis was established to study the operation characteristics of those systems by Yang et al. (2015). Lu et al. (2017a) and Lu et al. (2017b) also constructed a gas refrigeration system with the thermal transpiration effect as working principle. Lu et al. (2014b) and Wang et al. (2018) brought forth two novel types of hybrid vapor compression refrigeration system employing the Knudsen compressor combined with injector or vortex tube, respectively. The system arrangement can be designed flexibly according to different refrigeration requirements, which can not only improve refrigeration efficiency but also use low-grade heat energy. If the hybrid refrigeration system composed of Knudsen compressor and vortex tube was used to cool a control room of 50 m2, the cooling cost of ¥ 11,132.52 could be saved over the whole year according to Wang et al. (2018).