Monte Carlo simulation of a LSC based on stacked layers of fiber arrays with core-coating different absorbing properties.

In this work, a Monte Carlo ray-tracing model for the simulation and optimization of a fiber Luminescent Solar Concentrator (LSC) based on stacked layers of fiber arrays is developed and validated. The fiber LSC efficiency improvements are compared against a conventional planar LSC. We developed a new model to analyze the performance of different configurations of bulk-doped fibers and fibers constituted by a doped coating and a passive core. These configurations are analyzed also varying fiber packing geometry diameters, and length. Due to the exceptionally low absorption coefficient of the silica fibers (αwg ≈ 10-4 cm-1), concentration factors of up to 1.9 are predicted when dimensions are scaled over 1 m2, which improve more than twice the maximum concentration factor ever reported. These results serve as a preliminary theoretical study for the future development of a new LSC design based on flexible silica micro-fibers coated with Si-QDs doped poly(lauryl methacrylate) (PLMA) layers.

Does complexity relate to compensation? A comparison of relative value units in initial versus recurrent inguinal hernia repair.

PURPOSE: Work relative value units (wRVUs) can be used as a compensation model based on the effort required for providing a service and helps to determine adequate compensation for physicians. Thus, more complex surgical procedures that require greater technical skills and time should yield greater compensation. There are limited data comparing wRVUs and operative times within common general surgery procedures such as inguinal hernia repair. This study aims to compare mean operative times and wRVUs per minute between primary and recurrent inguinal hernia repairs, the latter being considered as a more difficult procedure to perform. METHODS: A retrospective analysis of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was performed to identify all patients undergoing primary inguinal hernia repair and recurrent inguinal hernia repair by general surgeons over a 6-year period (2012-2017). Calculation and comparison of mean operative times, wRVUs, and wRVU per minute were performed. RESULTS: A total of 134,391 patients were included in the analysis. 121,235 underwent primary inguinal repair and 13,156 patients underwent repair of recurrent inguinal hernia. Patients were distributed within open/reducible, open/incarcerated and laparoscopy groups. Mean operative time and RVUs were greater for recurrent inguinal procedures (p < 0.0001). Consistently, RVU per minute was also found to be higher for recurrent procedures within the different groups analyzed. CONCLUSION: Appropriately, general surgeons are reimbursed at a higher rate per minute in recurrent cases, regardless of the technique used.