Thermal energy storage of R1234yf, R1234ze, R134a and R32/MOF-74 nanofluids: a molecular simulation study

Thermal energy storage can be carried out by working fluid adsorbing and desorbing in porous materials. In this paper, the energy storage properties of four refrigerants, R1234yf, R1234ze, R134a and R32, with M-metal organic framework (MOF)-74 (M = Zn, Ni, Mg, Co) nanoparticles are investigated using molecular dynamics simulations and grand canonical Monte Carlo simulations. The results show that M-MOF-74 can adsorb more R32 and R134a than R1234yf and R1234ze, as the molecular structures of R32 and R134a are smaller than those of R1234yf and R1234ze. Mg-MOF-74 owns a higher adsorbability than the other MOFs. The energy storage properties of the studied refrigerants can be enhanced when the sum of thermodynamic energy change of MOF particles and the desorption heat of fluid in MOFs is larger than the enthalpy change of pure organic fluid. The R1234yf/M-MOF-74 (M = Co, Mg, Ni) nanofluid can store more energy than other refrigerants/M-MOF-74 (M = Co, Mg, Ni) nanofluid. The energy storage enhancement ratios of R1234yf, R1234ze and R134a with Mg-MOF-74 nanoparticles are higher than those of other M-MOF-74 (M = Co, Ni, Zn) materials

In-situ cosmogenic ³⁶Cl denudation rates of carbonates in Guizhou karst area

This study quantifies surface denudation of carbonate rocks by the first application of in-situ cosmogenic <sup>36</sup>Cl in China. Concentrations of natural Cl and in-situ cosmogenic <sup>36</sup>Cl in bare carbonates from Guizhou karst areas were measured with isotope dilution by accelerator mass spectrometer. The Cl concentration varied from 16 to 206 ppm. The <sup>36</sup>Cl concentrations were in range of (0.8–2.4)×106 atom g−1, resulting in total denudation rates of 20–50 mm ka−1 that averaged over a 104–105 a timescale. The <sup>36</sup>Cl-denudation rates showed roughly a negative correlation with the local mean temperature. This preliminary observation may suggest the variations of proportions of chemical weathering and physical erosion in denudation process, depending upon local climatic conditions

A literature review of sustainable consumption and production:A comparative analysis in developed and developing economies

Sustainable consumption and production is identified as one of the essential requirements for sustainable development. Due to different economic conditions and socio-cultural factors, sustainable consumption and production requires a diverse focus in developing and developed economies. To date, few efforts have been made to systematically compare the status of sustainable consumption and production and its direction from the perspective of developing and developed economies. This paper provides a literature review of published articles in international scientific journals related to sustainable consumption and production between 1998 and 2018 inclusive. Three carefully designed questions are proposed and answered in this article, forming the basis for conducting a comprehensive comparative analysis of the differences and challenges in sustainable consumption and production practices within developed and developing economies. The findings strongly suggest that countries in Europe hold international leadership in sustainable consumption and production practices. This finding, alongside others, is analyzed and discussed in greater detail in this paper, resulting in the articulation of gaps and future research opportunities in the current body of the literature

Mechanisms for electron transport in atomic-scale one-dimensional wires: soliton and polaron effects

We study one-electron tunneling through atomic-scale one-dimensional wires in the presence of coherent electron-phonon (e-ph) coupling. We use a full quantum model for the e-ph interaction within the wire with open boundary conditions. We illustrate the mechanisms of transport in the context of molecular wires subject to boundary conditions imposing the presence of a soliton defect in the molecule. Competition between polarons and solitons in the coherent transport is examined. The transport mechanisms proposed are generally applicable to other one-dimensional nanoscale systems with strong e-ph coupling.Comment: 7 pages, 4 figures, accepted for publication in Europhys. Let

Elevation Extraction from Spaceborne SAR Tomography Using Multi-Baseline COSMO-SkyMed SAR Data

SAR tomography (TomoSAR) extends SAR interferometry (InSAR) to image a complex 3D scene with multiple scatterers within the same SAR cell. The phase calibration method and the super-resolution reconstruction method play a crucial role in 3D TomoSAR imaging from multi-baseline SAR stacks, and they both influence the accuracy of the 3D SAR tomographic imaging results. This paper presents a systematic processing method for 3D SAR tomography imaging. Moreover, with the newly released TanDEM-X 12 m DEM, this study proposes a new phase calibration method based on SAR InSAR and DEM error estimation with the super-resolution reconstruction compressive sensing (CS) method for 3D TomoSAR imaging using COSMO-SkyMed Spaceborne SAR data. The test, fieldwork, and results validation were executed at Zipingpu Dam, Dujiangyan, Sichuan, China. After processing, the 1 m resolution TomoSAR elevation extraction results were obtained. Against the terrestrial Lidar ‘truth’ data, the elevation results were shown to have an accuracy of 0.25 ± 1.04 m and a RMSE of 1.07 m in the dam area. The results and their subsequent validation demonstrate that the X band data using the CS method are not suitable for forest structure reconstruction, but are fit for purpose for the elevation extraction of manufactured facilities including buildings in the urban area