[en] Highlights: • A novel multi-tank TES for solar-power air conditioning was proposed. • An optimized control strategy of multi-tank TES was proposed. • The number of tanks had little effect on duration time of IHIWT in multi-tank TES. • Longer duration time of IHIWT was obtained after optimized control strategy was adopted. - Abstract: The volume of hot storage tank in sensible thermal energy storage (STES), integrated with solar-powered air conditioning to mitigate the misalignment between supply and demand, is too big which results in great thermal inertia. In this paper, a novel multi-tank thermal energy storage (TES) system for solar-power air conditioning, with the advantages of quick temperature rising and outstanding ability to fit variable weather, was proposed to mitigate the contradictions between demand and supply. In order to investigate effect of the number of tanks (NT) on system response time (SRT), total energy grade of water in tanks and temperature variations in charging and discharging periods, a series of experiments of TESs with different number of tanks (total volume of tanks is constant) were conducted under the same solar radiation conditions. Results show that the energy grade of water in tanks is improved through dividing thermal energy storage system into several tanks with different priorities of charging and discharging, and SRT decreases by 6.95 h in four-tank TES, compared with one-tank TES. Furthermore, the duration time of ideal heating inlet water temperature (IHIWT) in entire operational period increases slowly with the number of tanks, because NT has opposite effects on duration time of IHIWT in charging and discharging periods. An optimized control strategy that tanks stored heat successively in charging period and released heat simultaneously in discharging period was proposed. It is notable that the duration time of IHIWT in four-tank TES increases 2.59 h, about 26.67%, after the optimized control strategy is adopted. Therefore, the optimized TES makes the single-effect absorption chiller run at a high COP over a long time without strong variations of COP, compared with other TESs.

[en] Highlights: • An air compression expansion cycle for plating wastewater treatment is proposed. • The required pressure ratio is 3.89 to improve air temperature from 45 °C to 120 °C. • The inlet air temperature of tower can achieve 159.6 °C when pressure ratio is 5.5. • The greatest inlet air humidity of tower is 6.37 g·kg⁻¹ when pressure ratio is 2. • The system efficiency ratio can achieve 7.13 kg·kWh⁻¹. Using traditional thermal evaporation to treat electroplating wastewater still consumes a lot of energy and it is impossible to completely separate salt and water. In order to separate salt and water with a high efficiency, a novel system combining air compression expansion cycle and spray drying tower is proposed for electroplating wastewater treatment. It is a good attempt to use the air compression expansion cycle as a component to provide service of heat and humidity treatment for the tower, and the feasibility of this combination is explored. In the paper, effects of compressor inlet parameters and pressure ratio on system performance are investigated, and the required pressure ratio is analyzed with different tower inlet temperatures. Meanwhile, the system efficiency ratio is compared with other systems. It is revealed that adjusting air compression expansion cycle to match spray drying tower is beneficial for the operation of the tower. The inlet air temperature of tower can realize to 159.6 °C, and its humidity is less than 6.37 g·kg⁻¹. What’s more, increasing of inlet air humidity in compressor is proved advantageous for promoting system performance, and selecting appropriate inlet air temperature and pressure ratio of compressor can meet the demand of the spray drying tower and result in the improvement of system performance. Moreover, as the temperature difference between inlet of compressor and tower is increased, the pressure ratio required of system is increased. In addition, the system efficiency ratio can achieve 7.13 kg·kWh⁻¹, and it is energy-efficient comparing with other systems.

[en] Cylindrical bismuth nanopillars with diameters between 130 and 1100 nm were fabricated by electron beam lithography and electroplating. The microstructure of the electrodeposited bismuth was established to be polycrystalline with a wide distribution of grains from ∼0.1 to 1 μm in size. A clear transition in the mechanism governing the plastic deformation of bismuth nanopillars is observed as the nanopillar size becomes comparable with the average grain size of 280 nm. In larger nanopillar specimens, where the average grain size is much smaller than the nanopillar diameter, deformation is dominated by grain boundary-mediated mechanisms. When the bismuth nanopillar diameter approaches the average grain size the deformation behavior transitions to a mechanism dominated by dislocation dynamics. This transition is identified by post-compression scanning electron microscopy, strain rate sensitivity, and average flow stresses.

[en] Highlights: ► Pd, Co, and Rh nano-pillars with diameter of ∼130 nm were fabricated by using novel electron beam lithography and electroplating techniques. ► Uniaxial compression load and displacement responses of the nanopillars were characterized. ► Pd nano-pillars have the highest fracture toughness followed by Co and Rh pillars. ► Tangent moduli of the three materials were extracted from the experimental results. - Abstract: Novel fabrication techniques were developed to manufacture polycrystalline palladium, cobalt, and rhodium nanopillars with diameters of approximately 130 nm. These nanostructures have length-to-radius ratios in the range of 4 and 20. Using uniaxial nano-compression techniques, the buckling behaviors of the produced nanopillars were characterized and critical buckling loads were extracted. The tangent moduli, which were extracted from plots of critical buckling load as a function of effective specimen cross-sectional area, of palladium, cobalt, and rhodium nanopillars are 90 ± 6 GPa, 175 ± 9 GPa, and 375 ± 23 GPa, respectively. As expected, these calculated values are slightly smaller than the bulk polycrystalline elastic moduli for all three materials. Post compression scanning electron microscope images revealed ductile behavior for palladium nanostructures, while cobalt and rhodium specimens failed by fracture.

[en] Highlights: → A novel fabrication method was developed for single-crystalline tin nanopillars. → BCT tin nanopillar strain-rate sensitivity is similar to bulk tin. → BCT tin nanostructures exhibit a strength size effect similar to FCC metals. → Synchrotron XRD results showed no accumulation of dislocations in deformed pillars. → This is believed to be the 1st report on the tin nanopillar mechanical properties. - Abstract: Vertically aligned, cylindrical tin nanopillars have been fabricated via an electron beam lithography and electroplating method. Characterization by a non-destructive synchrotron X-ray microdiffraction (μSXRD) technique revealed that the tin nanostructures are body-centered tetragonal and are likely single-crystalline, or consist of a few large grains. The mechanical properties of tin nanopillars with average diameters of 920 nm, 560 nm, and 350 nm were studied by uniaxial compression in a nanoindenter outfitted with a flat punch diamond tip. The results of compression tests reveal strain rate sensitivity for nanoscale tin deformation, which matches closely to the previously reported bulk tin values. However, unlike bulk, tin nanopillars exhibit size-dependent flow stresses where smaller diameter specimens exhibit greater attained strengths. The observed size-dependence matches closely to that previously reported for single-crystalline face centered cubic metals at the nanoscale. μSXRD data was used to compare the dislocation density between as-fabricated and deformed tin nanopillars. Results of this comparison suggest that there is no measurable accumulation of dislocations within deformed tin nanopillars.

[en] Sub-micron-scale columnar cadmium structures were tested in uniaxial compression. Transmission electron microscopy and electron diffraction analysis indicated that the cadmium pillars are virtually single crystalline. Compression results revealed that the mechanical strength of small-scale cadmium is strain rate sensitive and size dependent. Specimens with diameters near 0.5 and 1.1 μm are slightly stronger than bulk. However, as the cadmium structure size reduces to near 0.1 μm, the mechanical strengths exceed ∼1 GPa, approaching the theoretical strength of cadmium.

[en] The mechanical properties exhibited by sub-micron scale columnar structures of cobalt, fabricated by electron beam lithography and electroplating techniques, were investigated through uniaxial compression. Transmission electron microscopy analyses show these specimens possess a microstructure with sub-micron grains which are elongated and aligned near to the pillar loading axis. In addition, small nanocrystalline cobalt crystals are also present within the columnar structure. These specimens display exceptional mechanical strength comparable with both bulk polycrystalline and nanocrystalline cobalt deposited by electroplating. Size-dependent softening with shrinking sample dimensions is also observed in this work. Additionally, the strength of these sub-micron structures appears to be strain rate sensitive and comparable with bulk nanocrystalline cobalt specimens.