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1.
Understanding the in-situ transformation of ▫$Cu_xO$▫ interlayers to increase the water splitting efficiency in NiO/n-Si photoanodes
Chao Feng, Zhi Liu, Huanxin Ju, Andraž Mavrič, Matjaž Valant, Jie Fu, Beibei Zhang, Yanbo Li, 2024, original scientific article

Abstract: The buried interface tens of nanometers beneath the solid-liquid junction is crucial for photocarrier extraction, influencing the overall efficiency of photoelectrochemical devices. Precise characterization of the interfacial properties is essential for device optimization but remains challenging. Here, we directly probe the in situ transformation of a CuxO interlayer at the NiO/n-Si interface by hard X-ray photoelectron spectroscopy. It is found that Cu(I) in the CuxO interlayer gradually transforms to Cu(II) with air exposure, forming an energetically more favorable interface and improving photoanode’s efficiency. Based on this finding, a reactive e-beam evaporation process is developed for the direct deposition of a CuO interlayer, achieving a half-cell solar-to-hydrogen efficiency of 4.56% for the optimized NiO/CuO/n-Si heterojunction photoanode. Our results highlight the importance of precision characterization of interfacial properties with advanced hard X-ray photoelectron spectroscopy in guiding the design of efficient solar water-splitting devices.
Keywords: photo anode, energy harvesting, nickel oxide, interface
Published in RUNG: 01.08.2024; Views: 1068; Downloads: 10
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2.
Time restrictions in forest operations planning
Boštjan Kepic, 2016, master's thesis

Abstract: This master’s thesis deals with annual harvest operations (AHO) planning with consideration of time restrictions. We developed five models of binary integer linear programming (BILP) that schedule working groups to harvest unit areas (HUAs) according to the lowest cost possible. Total AHO costs include felling and skidding costs, transportation costs, and machine relocation costs. The first model is based on the presumption that harvesting can be planned and executed freely throughout the year. In other four, scheduling was subject to time restrictions in HUAs and differed according to the extent of time restrictions. The second model takes into account time restrictions due to unfavourable natural conditions, the third model due to disturbance-free areas of animal species, the fourth and fifth model concurrently include the impact of time restrictions due to natural conditions and disturbance-free areas. The annual workplace time in Model 2 is reduced by 14.2 %, in Model 3 by 16.9 %, in Model 4 by 29.3 % and in Model 5 by 42.3 %. The model tool used to test all the models was designed in Microsoft Excel. All five models were tested with OpenSolver 2.7.1 software. Increasing the extent of time restrictions in forest operations reduces the utilization of the annual workplace time. In testing the second model, we demonstrated that with proper organisation of an AHO plan the planner can influence the working days fallout. In the other three models, we were able to ensure the implementation of AHO plan by introducing extra working groups. Further, we confirmed that time restrictions affect the scheduling of the working groups and the sequencing of tasks. The increases in total AHO costs were explained as an increase in working groups’ costs due to lower utilization rate, an increase in depreciation costs of machines and costs due to unrealized allowable annual cut and timber sales planned for the current year. We tested each model on two examples.
Keywords: time restrictions, binary integer programming, forestry, annual harvest operations planning, harvesting, scheduling working teams
Published in RUNG: 20.09.2016; Views: 7437; Downloads: 265
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