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The application of the ammonia-water absorption refrigeration systems is limited by the absorption effect of the absorber. Installing atomizer at the absorber can significantly enlarge the liquid-vapor contact area. In this paper, we develop a mathematical model of system energy consumption coupled to absorption process, in which the effect of the atomizer on the mass and heat transfer is taken into account. The effect of the droplet parameters on the absorption effect and the energy efficiency of the system are discussed separately for the parallel and series installing strategies. Although the size reduction can improve the absorption effect, the increment of ammonia absorbed rate changes insignificantly with a smaller diameter of droplets. For each droplet diameter, a larger atomization ratio for the series model implies better absorption, but there is an optimal atomization ratio for the parallel model to reach the maximum ammonia absorbed rate, and the relationship between the droplets diameter and atomization ratio is also introduced. Meanwhile, the primary energy efficiency is used as an evaluation metric, then the droplets parameters in parallel and series modes are optimized by taking into account the energy input of the atomizer. The optimal parameter combination of parallel model is droplets diameter of 12.4 μm and atomization ratio of 0.823. At this time, the atomizer power is 0.51 W, and the system PEE is increased by 35.99 %. Whereas, the optimal atomizer power is a function of the droplet size in the series mode. As the droplets diameter of 0–100 μm, the optimal atomizer power decreased and the maximum value of the PEE increased with the droplet diameter. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a heavy metal toxicant as a common pollutant derived from many agricultural and industrial sources. The absorption of Cd takes place primarily through Cd-contaminated food and water and, to a significant extent, via inhalation of Cd-contaminated air and cigarette smoking. Epidemiological data suggest that occupational or environmental exposure to Cd increases the health risk for osteoporosis and spontaneous fracture such as itai-itai disease. However, the direct effects and underlying mechanism(s) of Cd exposure on bone damage are largely unknown. We used primary bone marrow-derived mesenchymal stromal cells (BMMSCs) and found that Cd significantly induced BMMSC cellular senescence through over-activation of NF-κB signaling pathway. Increased cell senescence was determined by production of senescence-associated secretory phenotype (SASP), cell cycle arrest and upregulation of p21/p53/p16INK4a protein expression. Additionally, Cd impaired osteogenic differentiation and increased adipogenesis of BMMSCs, and significantly induced cellular senescence-associated defects such as mitochondrial dysfunction and DNA damage. Sprague-Dawley (SD) rats were chronically exposed to Cd to verify that Cd significantly increased adipocyte number, and decreased mineralization tissues of bone marrow in vivo. Interestingly, we observed that Cd exposure remarkably retarded bone repair and regeneration after operation of skull defect. Notably, pretreatment of melatonin is able to partially prevent Cd-induced some senescence-associated defects of BMMSCs including mitochondrial dysfunction and DNA damage. Although Cd activated mammalian target of rapamycin (mTOR) pathway, rapamycin only partially ameliorated Cd-induced cell apoptosis rather than cellular senescence phenotypes of BMMSCs. In addition, a selective NF-κB inhibitor moderately alleviated Cd-caused the senescence-related defects of the BMMSCs. The study shed light on the action and mechanism of Cd on osteoporosis and bone ageing, and may provide a novel option to ameliorate the harmful effects of Cd exposure. [Display omitted] • Cadmium (Cd) exhibited an acute toxicity to primary bone marrow-derived mesenchymal stromal cells (BMMSCs). • Cd induced BMMSC senescence, activation of NF-κB pathway, and mitochondrial dysfunction. • Cd exposure induced osteoporosis and adipogenesis linking to bone ageing in vivo. • Cd impaired bone repair and regeneration in a cranial bone damaging model. • Melatonin and NF-κB inhibitor can partially prevent Cd-induced BMMSC senescence-related defects. [ABSTRACT FROM AUTHOR]

• Theoretical calculation of Mobility spectrum in DG-SOI MOSFETs. • NEGF-Poisson solver with scattering to calculate mobility. • Conductivity and mobility calculation using Kubo-Greenwood formalism. • Identifying main subband components in the Silicon contributing to the mobility. Modern electronic devices consist of several semiconductor layers where each layer exhibits unique carrier transport properties that can be represented by a unique mobility characteristic. To date, the mobility spectrum analysis technique is the main approach that has been developed and applied to the analysis of conductivity mechanisms of multi-carrier semiconductor structures and devices. Currently, there are no theoretical calculations of the mobility distribution in semiconductor structures or devices and specifically in MOSFET devices. In this article, we present a theoretical study of the electron mobility distribution in planar fully-depleted silicon-on-insulator (FD-SOI) transistors employing quantum mechanical modelling. The simulation results indicate that electronic transport in the 10 nm thick Si channel layer at room-temperature is due to two distinct and well-defined electron species for channel length varying from 50 nm to 200 nm. The two electron mobility distributions provide clear evidence of sub-band modulated transport in 10-nm thick Si planar FD-SOI MOSFETs that are associated with primed and non-primed valleys of silicon. The potential of the top gate electrode has been modulated, and thus only the top channel inversion-layer electron population transport parameters have been investigated employing self-consistent non-equilibrium Green's function (NEGF)–Poisson numerical calculations. The numerical framework presented can be used to interpret experimental results obtained by magnetic-field dependent geometrical magnetoresistance measurements and mobility spectrum analysis, and provides greater insight into electron mobility distributions in nanostructured FET devices. [ABSTRACT FROM AUTHOR]