Search

The aerodynamic behavior of the fans array of the direct air-cooled condenser is different from that of a single fan because of the interaction effect between fans and the influence of wind. In this paper, a scale-down fan array experimental platform with measurement of the airflow and ambient wind speed is established to study the fan array partition schemes and cluster effect. The divisional cluster factors are obtained by experiment and generalized by random forest regression. The dynamic models of the condenser backpressure are introduced by the moving-boundary method. To achieve transient performance, a divisional control strategy for the direct air-cooled condenser is realized by MPC-PID cascade control. The simulation result shows that the fan power consumption is reduced by 14.7% compared to the existing control strategy. Furthermore, the wind speed disturbance is quickly suppressed cascade control.

Supercapacitors (SCs) have received worldwide attention as energy devices for wearable smart systems. Biocompatibility and self-charging property of SCs require serious consideration, but the related studies are just in their infancy. Here, a “sweat-chargeable” on-skin SC using biocompatible NaCl electrolyte and freestanding polyaniline/carbon nanotube (PANI/CNT) electrodes is presented. Although the capacitance of the biocompatible SC is about half of that using conventional skin-irritated H2SO4 electrolyte, the potential window extends from 0.8 V to 1.4 V. Thus, a higher energy density can be obtained. The self-charging property is achieved by simply adding a piece of Zn foil on one electrode with silver paste, which provides energy source and maintains a super compact two-electrode configuration of SC. The sweat absorbed from human body could trigger the redox reaction between the added Zn foil and oxygen in air, resulting in the self-charging of the device to 0.652 V in 6 min. To demonstrate its wearability in real applications, a “sweat-chargeable” band is prepared that can spontaneously power a timer or a pedometer when the user is exercising. This work has made a further step in the development of biocompatible and practical wearable energy devices.

Nowadays, multi-functional systems driven by solar energy have been explored to alleviate the crisis of energy and freshwater scarcity. However, it remains a great challenge to integrate multi-functions into one hybrid system with a monolithic material, which can harvest, convert and store solar energy synergistically. Here, we firstly propose a multi-functional carbon nanotube paper, which starts from a material level to solve these problems. The carbon nanotube paper is fabricated by vacuum filtration. It exhibits high efficiency of solar-thermal conversion. Secondly, three types of energy conversion/storage systems (e.g., solar-thermal evaporation system, solar-thermoelectric generation system, and supercapacitor) are constructed based on the carbon nanotube paper, which extend the research to a device level. The solar-thermal evaporation system shows an evaporation rate of 1.28 kg m-2h−1 under simulated sunlight irradiation of 1 kW m−2. The solar-thermoelectric generation system demonstrates a stable electric power generation with an output voltage of 100 mV under light irradiation of 1 kW m−2. The supercapacitors perform the energy storage function with an areal specific capacitance of 19.6 mF cm−2. These devices and systems can be used in freshwater generation (0.84 kg m-2h−1, sunlight irradiation of 1 kW m−2), water purification/desalination (inorganic ions rejection larger than 99.9%) and portable solar charging system (maximum output voltage of 5 V). Finally, a hybrid energy system is innovatively proposed from the system level to simultaneously produce freshwater, generate and store electric power. Through the synergetic coupling of solar conversion and storage technologies, the hybrid energy system can supply sustainable freshwater and electricity for remote areas in daily life, highlighting the superiority of multi-energy (thermal energy, electrical energy, and electrochemical energy) complementary.

The MitraFix valve (MitrAssist Lifesciences, Shanghai, China) consists of a D-shaped nitinol frame and 3 bovine pericardium leaflets ([Figures 1A and 1B][1]). The 30-F transapical delivery system has 2 built-in echogenic markers for height and D-shape orientation, which facilitate implanting the

The number and popularity of smartphone applications is rising dramatically. Users install and use applications depending on their needs and interests. Applications on smartphones convey lots of personal information, providing us a new lens to well profile users. In this paper, we first describe application information for user profiling. Second, we analyze what types of user information can be profiled from smartphone applications. Then, we overview the previous work and summarize the state-of-the-art methods for profiling users from application data. We also describe implications from different perspectives. Finally, the challenges in profiling users from smartphone applications are discussed.