Recent Issues and Configuration Factors in Perovskite-Silicon Tandem Solar Cells towards Large Scaling Production

The unprecedented development of perovskite-silicon (PSC-Si) tandem solar cells in the last five years has been hindered by several challenges towards industrialization, which require further research. The combination of the low cost of perovskite and legacy silicon solar cells serve as primary drivers for PSC-Si tandem solar cell improvement. For the perovskite top-cell, the utmost concern reported in the literature is perovskite instability. Hence, proposed physical loss mechanisms for intrinsic and extrinsic instability as triggering mechanisms for hysteresis, ion segregation, and trap states, along with the latest proposed mitigation strategies in terms of stability engineering, are discussed. The silicon bottom cell, being a mature technology, is currently facing bottleneck challenges to achieve power conversion efficiencies (PCE) greater than 26.7%, which requires more understanding in the context of light management and passivation technologies. Finally, for large-scale industrialization of the PSC-Si tandem solar cell, the promising silicon wafer thinning, and large-scale film deposition technologies could cause a shift and align with a more affordable and flexible roll-to-roll PSC-Si technology. Therefore, this review aims to provide deliberate guidance on critical fundamental issues and configuration factors in current PSC-Si tandem technologies towards large-scale industrialization. to meet the 2031 PSC-Si Tandem road maps market target.

John R. Connon of Elora, Ontario and his 360-degree panoramic camera

John R. Connon (1862-1931) was a photographer and inventor who lived in Elora, Ontario, Canada during a time of remarkable innovations in the medium of photography. In 1886, Connon began to develop one of the earliest cameras to be capable of a full 360-degree photographic panorama using a single exposure. His early dedication to the use of flexible roll film, introduced by the Eastman Dry Plate and Film Company in 1885, allowed Connon to invent a camera that was ahead of its time. Through an agreement with C. P. Stirn, of C. P. Stirn's Patent Photographic Concealed Vest Cameras, Connon's design was transformed into the Wonder panoramic camera, further inspiring a succession of full-circle panoramic cameras including the Kodak Cirkut cameras. This thesis explores the history of Connon and his invention while acknowledging the history of this little-known Canadian inventor’s important contribution to the history of photographic technology.

John R. Connon of Elora, Ontario and his 360-degree panoramic camera

John R. Connon (1862-1931) was a photographer and inventor who lived in Elora, Ontario, Canada during a time of remarkable innovations in the medium of photography. In 1886, Connon began to develop one of the earliest cameras to be capable of a full 360-degree photographic panorama using a single exposure. His early dedication to the use of flexible roll film, introduced by the Eastman Dry Plate and Film Company in 1885, allowed Connon to invent a camera that was ahead of its time. Through an agreement with C. P. Stirn, of C. P. Stirn's Patent Photographic Concealed Vest Cameras, Connon's design was transformed into the Wonder panoramic camera, further inspiring a succession of full-circle panoramic cameras including the Kodak Cirkut cameras. This thesis explores the history of Connon and his invention while acknowledging the history of this little-known Canadian inventor’s important contribution to the history of photographic technology.

Anisotropic Analysis of Springback in FRF Process With Variable Cross Section Using Hill and Barlat Criteria

The Flexible Roll Forming (FRF) process with the ability to produce parts with variable width and depth was formed to be used in industries such as automotive, construction, and similar industries. One of the disadvantages of this process is the spring-back defect, which prevents the desired profile from being achieved. In this paper, experimental and numerical analysis of the spring-back phenomenon using Hill, Barlat, and Von Mises yield criteria. Also, the effect of bending angle, material, and sheet thickness parameters on this defect was investigated. The process for the three types of 1050 aluminum, low carbon steel, and 430 stainless steel was simulated using the VUMAT subroutine of Abaqus software. In these simulations, for each material, three thicknesses of 0.4, 0.7 and 1 mm with bending angles of 25 and 45 degrees were considered. Experimental experiments were performed using the FRF machine. Validation of numerical simulation results was performed by comparing experimental results. The results showed that the Barlat criterion has a more accurate prediction of spring-back than the other two criteria. The results also showed that the spring-back ratio of sheets with a thickness of 0.4 mm compared to 1 mm for low carbon, aluminum, and stainless steel are 1.5, 2.5, and 3.2, respectively.

Application of Support Vector Regression and Genetic Algorithm to Reduce Web Warping in Flexible Roll-Forming Process

In a flexible roll-forming process, a metal blank is incrementally deformed into the desired shape with a variable cross-sectional profile by passing the blank through a series of forming rolls. Because of the combined effects of process and material parameters on the quality of the roll-formed product, the approaches used to optimize the roll-forming process have been largely based on experience and trial-and-error methods. Web warping is one of the major shape defects encountered in flexible roll forming. In this study, an optimization method was developed using support vector regression (SVR) and a genetic algorithm (GA) to reduce web warping in flexible roll forming. An SVR model was developed to predict the web-warping height, and a response surface method was used to investigate the effect of the process parameters. In the development of these predictive models, three process parameters—the forming-roll speed condition, leveling-roll height, and bend angle—were considered as the model inputs, and the web-warping height was used as the response variable. The GA used the web-warping height and the cost of the roll-forming system as the fitness function to optimize the process parameters of the flexible roll-forming process. When the flexible roll-forming process was carried out using the optimized process parameters, the obtained experimental results indicated a reduction in web warping. Hence, the feasibility of the proposed optimization method was confirmed.