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Abstractπ‐Conjugated polyelectrolytes (CPEs) have been studied as interlayers on top of a separate hole transport layer (HTL) to improve the wetting, interfacial defect passivation, and crystal growth of perovskites. However, very few CPE‐based HTLs have been reported without rational molecular design as ideal HTLs for perovskite solar cells (PeSCs). In this study, the authors synthesize a triphenylamine‐based anionic CPE (TPAFS‐TMA) as an HTL for p‐i‐n‐type PeSCs. TPAFS‐TMA has appropriate frontier molecular orbital (FMO) levels similar to those of the commonly used poly(bis(4‐phenyl)‐2,4,6‐trimethylphenylamine) (PTAA) HTL. The ionic and semiconducting TPAFS‐TMA shows high compatibility, high transmittance, appropriate FMO energy levels for hole extraction and electron blocking, as well as defect passivating properties, which are confirmed using various optical and electrical analyses. Thus, the PeSC with the TPAFS‐TMA HTL exhibits the best power conversion efficiency (PCE) of 20.86%, which is better than that of the PTAA‐based device (PCE of 19.97%). In addition, it exhibits negligible device‐to‐device variations in its photovoltaic performance, contrary to the device with PTAA. Finally, a large‐area PeSC (1 cm2) and mini‐module (3 cm2), showing PCEs of 19.46% and 18.41%, respectively, are successfully fabricated. The newly synthesized TPAFS‐TMA may suggest its great potential as an HTL for large‐area PeSCs.

To alleviate the pressure of energy utilization of buildings, more attention was focused on the utilization of GWSHP (groundwater source heat pump) systems. However, there have been many debates on feasibility. This paper is to study the suitability and feasibility of GWSHP systems in different climate zones. A simulation model of a GWSHP system is established based on TRNSYS software in the severe cold climate zones A and B, cold climate zones, hot summer and cold winter climate zones, and the hot summer and warm winter climate zones. Simultaneously, the reliability and energy-saving benefits of GWSHP systems in typical residential buildings situated in different climate zones are deeply analyzed. Results reveal that the operating performance of GWSHP systems is considered as the best in the climate zones that need both heating and cooling loads for residential buildings. In contrast, the energy-saving benefits of the GWSHP system in typical residential buildings are deemed to be higher in the cold climate zones and severe cold climate zones. Overall, compared with the ASHP, the economy of the system is generally better based on economic analysis.

Owing to the growing interest of bioconvection flow of nanomaterials, many investigations on this topic have been performed, especially in this decade. The bioconvection flow of nanofluid includes some novel significance in era of biotechnology and bio-engineering like bio-fuels, microbial enhanced oil recovery, enzymes, pharmaceutical applications, petroleum engineering, etc. The current analysis aims to explore the various thermal properties of Sutterby nanofluid over rotating and stretchable disks with external consequences of variable thermal conductivity, heat absorption/generation consequences, activation energy and thermal radiation. The considered flow problem is changed into dimensionless form with convenient variables. The numerical structure for the obtained non-dimensional equations is numerically accessed with built-in shooting technique. The consequences of various physical parameters are observed for enhancement of velocity, temperature, concentration and motile microorganism. It is noted that both axial and tangential velocity components decrease with Reynolds number and buoyancy ratio parameter. The nanofluid concentration improves with activation energy and concentration Biot number. Moreover, an improved microorganisms profile is noticed with microorganism Biot number and bioconvection Rayleigh number.

In recent years, marine auxiliary diesel engine has been widely used to produce electricity in the large ocean-going ship. One of the main technical challenges for ocean-going ship is to reduce pollutant emissions from marine auxiliary diesel engine and to meet the criteria of disposal on ships pollutants of IMO (International Maritime Organization). Different technical changes have been introduced in marine auxiliary diesel engine to apply clean fuels to reduce pollutant emissions. The ultralow sulfur light fuel will be applied in diesel engine for emission reductions in China. This study is aimed to investigate the impact of fuel (ultralow sulfur light fuel) on the combustion characteristic, NOx and green house gas emissions in a marine auxiliary diesel engine, under the 50%-90% engine speeds and the 25%-100% engine torques. The experimental results show that, in the marine auxiliary diesel engine, the cylinder pressure and peak heat release rate increase slightly with the increase of engine torques, while the ignition advances and combustion duration become longer. With the increases of the engine speed and torque, the fuel consumption decreases significantly, while the temperature of the exhaust manifold increases. The NOx emissions increase significantly with the increases of the engine speed and torque. The NO emission increases with the increases of the engine speed and torque, while the NO2 emission decreases. Meanwhile, the ratio of NO2 and NO is about 1:1 when the diesel engine operated in the low speed and load, while the ratio increases significantly with the increases of engine speed and torque, due to the increase of the cylinder temperature in the diffusive combustion mode. Moreover, the CO2 emission increases with the increases of engine speed and torque by the use of ultralow sulfur light fuel.

COVID-19 pandemic has brought tremendous environmental burden due to huge amount of medical wastes (about 54,000 t/d as of November 22, 2020), including face mask, gloves, clothes, goggles, and sanitizer/disinfectant containers. A proper waste management is urgently required to mitigate the spread of the disease, minimize the environmental impacts, and take their potential advantages for further utilization. This work provides a prospective review on the possible thermochemical treatments for those COVID-19 related medical wastes (CMW), as well as their possible conversion to fuels. The characteristics of each waste are initially analyzed and described, especially their potential as energy source. It is clear that most of CMWs are dominated by plastic polymers. Thermochemical processes, including incineration, torrefaction, pyrolysis, and gasification, are reviewed in terms of applicability for CMW. In addition, the mechanical treatment of CMW into sanitized refuse-derived fuel (SRDF) is also discussed as the preliminary stage before thermochemical conversion. In terms of material flexibility, incineration is practically applicable for all types of CMW, although it has the highest potential to emit the largest amount of CO2 and other harmful gasses. Furthermore, gasification and pyrolysis are considered promising in terms of energy conversion efficiency and environmental impacts. On the other hand, carbonization faces several technical problems following thermal degradation due to insufficient operating temperature.

Abstract Gas crossover is an unavoidable phenomenon in proton exchange membrane fuel cells. Gas crossover leads to heat and water generations without conducting any useful works, hence increasing fuel consumption. Particularly, Gas crossover can result in the degradation and formation of pinholes inside the membrane. Therefore, the gas crossover is a critical factor significantly affecting the durability of a fuel cell and quality of the membrane. Herein, we numerically investigate the effects of gas crossover across the membrane in a proton exchange membrane fuel cell. A two-dimensional, two-phase, steady state model of the gas crossover using the partial differential equation solver FreeFem++, was built to investigate the crossover characteristics of hydrogen and oxygen across the membrane versus changes in operating conditions and various geometric structure of components in the proton exchange membrane fuel cell. Results indicated that higher equivalent weight of Nafion® is required to significantly decrease gas crossover phenomenon while the cell performance was reduced negligibly. In addition, as the increase in the stoichiometric flow ratio and channel length, the gas crossover decreased and the cell performance improved.

Owing to the storage and transportation problems of hydrogen fuel, exploring new methods of the realtime hydrogen production from ammonia becomes attractive. In this paper, non-thermal arc plasma (NTAP) combining with NiO/Al2O3 catalyst is developed to produce hydrogen from ammonia with high efficiency and large scale. The effects of ammonia gas flow rate and discharge power on the gas temperature, electron density, the hydrogen production rate, and energy efficiency were investigated. Experimental results show that the optical emission spectrum of NTAP working with pure ammonia medium was dominated by the atom spectrum of Hα, Hβ, and molecular spectrum of NH component. Under the optimum experimental condition of plasma discharge, the highest energy efficiency of hydrogen production reached 783.4 L/kW·h at NH3 gas flow rate of 30 SLM. When the catalyst was added, and heated by the NTAP simultaneously, the energy efficiency further increased to 1080.0 L/kW·h. Owing to the storage and transportation problems of hydrogen fuel, exploring new methods of the realtime hydrogen production from ammonia becomes attractive. In this paper, non-thermal arc plasma (NTAP) combining with NiO/Al2O3 catalyst is developed to produce hydrogen from ammonia with high efficiency and large scale. The effects of ammonia gas flow rate and discharge power on the gas temperature, electron density, the hydrogen production rate, and energy efficiency were investigated. Experimental results show that the optical emission spectrum of NTAP working with pure ammonia medium was dominated by the atom spectrum of Hα, Hβ, and molecular spectrum of NH component. Under the optimum experimental condition of plasma discharge, the highest energy efficiency of hydrogen production reached 783.4 L/kW·h at NH3 gas flow rate of 30 SLM. When the catalyst was added, and heated by the NTAP simultaneously, the energy efficiency further increased to 1080.0 L/kW·h.

Including solar power geneartion from 2018 to 2019 at a 3kW rooftop pv plant in the university of macau, with a resolation of 30 s, and the public weather report of Macau with a resolution of 1 hour.