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Rehan Younas

Publications and source records attributed to Rehan Younas.

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Predicting and Accelerating Nanomaterials Synthesis Using Machine Learning Featurization

Materials synthesis optimization is constrained by serial feedback processes that rely on manual tools and intuition across multiple siloed modes of characterization. We automate and generalize feature extraction of reflection high-energy electron diffraction (RHEED) data with machine learning to establish quantitatively predictive relationships in small sets (\~10) of expert-labeled data, saving significant time on subsequently grown samples. These predictive relationships are evaluated in a representative material system (\ce{W_{1-x}V_xSe2} on c-plane sapphire (0001)) with two aims: 1) predicting grain alignment of the deposited film using pre-growth substrate data, and 2) estimating vanadium dopant concentration using in-situ RHEED as a proxy for ex-situ methods (e.g. x-ray photoelectron spectroscopy). Both tasks are accomplished using the same materials-agnostic features, avoiding specific system retraining and leading to a potential 80\% time saving over a 100-sample synthesis campaign. These predictions provide guidance to avoid doomed trials, reduce follow-on characterization, and improve control resolution for materials synthesis.

cond-mat.mtrl-sci

Module Technology for Agrivoltaics: Vertical Bifacial vs. Tilted Monofacial Farms

Agrivoltaics is an innovative approach in which solar photovoltaic (PV) energy generation is collocated with agricultural production to enable food-energy-water synergies and landscape ecological conservation. This dual-use requirement leads to unique co-optimization challenges (e.g. shading, soiling, spacing) that make module technology and farm topology choices distinctly different from traditional solar farms. Here we compare the performance of the traditional optimally-titled North/South (N/S) faced monofacial farms with a potential alternative based on vertical East/West (E/W)-faced bifacial farms. Remarkably, the vertical farm produces essentially the same energy output and photosynthetically active radiation (PAR) compared to traditional farms as long as the PV array density is reduced to half or lower relative to that for the standard ground-mounted PV farms. Our results explain the relative merits of the traditional mono facial vs. vertical bifacial farms as a function of array density, acceptable PAR-deficit, and energy production. The combined PAR/Energy yields for the vertical bifacial farm may not always be superior, it could still be an attractive choice for agrivoltaics due to its distinct advantages such as minimum land coverage, least hindrance to the farm machinery and rainfall, inherent resilience to PV soiling, easier cleaning and cost advantages due to potentially reduced elevation.

physics.app-ph