Modeling of silicon nanocrystals based down-shifter for enhanced silicon solar cell performance

A transfer matrix model of a luminescent down-shifter (LDS) layer, consisting of silicon nanocrystals (Si-NCs) embedded in a silicon oxide matrix, on a silicon solar cells is presented. To enhance the efficiency of the silicon solar cell, we propose using a SiO2/Si-NCs double layer stack, as an anti-reflection-coating (ARC) and as a LDS material. The optical characteristics of this stack have been simulated and optimized as a front surface coating. The cell performances have been simulated by means of a two-dimensional device simulator and compared with the performances of a reference silicon solar cell. We found a 6% relative enhancement of the energy conversion efficiency with respect to the reference cell. We demonstrate that this enhancement results from the lower reflectance and from the down-shifter effect of the Si-NCs activated coating stack

Getting to Death: Race and the Paths of Capital Cases after \u3cem\u3eFurman\u3c/em\u3e

Decades of research on the administration of the death penalty have recognized the persistent arbitrariness in its implementation and the racial inequality in the selection of defendants and cases for capital punishment. This Article provides new insights into the combined effects of these two constitutional challenges. We show how these features of post-Furman capital punishment operate at each stage of adjudication, from charging death-eligible cases to plea negotiations to the selection of eligible cases for execution and ultimately to the execution itself, and how their effects combine to sustain the constitutional violations first identified 50 years ago in Furman. Analyzing a dataset of 2,328 first-degree murder convictions in Georgia from 1995–2004 that produced 1,317 death eligible cases, we show that two features of these cases combine to produce a small group of persons facing execution: victim race and gender, and a set of case-specific features that are often correlated with race. We also show that these features explain which cases progress from the initial stages of charging to a death sentence, and which are removed from death eligibility at each stage through plea negotiations. Consistent with decades of death penalty research, we also show the special focus of prosecution on cases where Black defendants murder white victims. The evidence in the Georgia records suggests a regime marred less by overbreadth in its statute than capriciousness and randomness in the decision to seek death and to seek it in a racially disparate manner. These two dimensions of capital case adjudication combine to sustain the twin failures that produce the fatal lottery that is the death penalty

Mass spectrometry application on the detection of Sildenafil in aqueous phases

Sildenafil, the active ingredient of Viagra (Figure n.1), is a drug helpful in solving erectile dysfunction problems and recently entered the list of emerging contaminants. The use of these pharmaceuticals is increasingly widespread among perfectly healthy young people (20 or 30 years old) who make them a dangerous abuse for "recreational" purposes together with ecstasy: the result is a synergistic amplification of their final effects, such as the feeling of euphoria, confusion, disorientation, hallucinations, tremors or, in severe cases, irregular heartbeat and even coma. According to the 2018 annual report prepared by the Italian Medicines Agency (AIFA), this compounds’ consumption had increased over time from 2.9 DDD (Defined Daily Dose assumed per 1000 inhabitants in the referred year) in 2014 to 3.6 DDD in 2018. Unfortunately, it is impossible to detect the actual quantity used from the population (young and patients) because the internet network is becoming a way of purchasing to avoid medical prescriptions. Indeed, some researchers [1] report that illicit trading with pharmaceuticals products from the Internet is not wholly conscious of the risks for health concerning the quality of these products, such as the possible presence of toxic impurities [2]. The increase in demand is powering the illegal trade via the web, and, consequently, the risk of using an ineffective/harmful to health drug is very high [3,4]. The human body does not fully utilize these drugs. An unknown quantity, probably transformed, is excreted with urine and faeces. The high consumption of this substance, globally accomplished by legal and illegal ways, and the fact that Wastewater treatment plants (WWTP) cannot remove all types of contaminants that enter the sewer legitimates thinking that they can pose a severe threat to ecosystems and human health [5]. The unambiguous analytical determination of the active parent drug and the identification of its transformation products are therefore indispensable to try understanding if the quantity found of this drug in wastewater and surface water is linked to actual medical use and to verify whether tertiary purification treatments of wastewater are effective in the removal. In this work, the identification and quantification of this pharmaceutical product in water and synthetic wastewater were performed by LC-ESI-LTQ/MS and confirmed by CID-MSn. Thanks to high mass precision and MS/MS capability, determination and structural interpretation of sildenafil and its transformation products were achieved

SiPM and front-end electronics development for Cherenkov light detection

The Italian Institute of Nuclear Physics (INFN) is involved in the development of a demonstrator for a SiPM-based camera for the Cherenkov Telescope Array (CTA) experiment, with a pixel size of 6$\times$6 mm$^2$. The camera houses about two thousands electronics channels and is both light and compact. In this framework, a R&D program for the development of SiPMs suitable for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different photosensors have been produced at Fondazione Bruno Kessler (FBK), with different micro-cell dimensions and fill factors, in different geometrical arrangements. At the same time, INFN is developing front-end electronics based on the waveform sampling technique optimized for the new NUV SiPM. Measurements on 1$\times$1 mm$^2$, 3$\times$3 mm$^2$, and 6$\times$6 mm$^2$ NUV SiPMs coupled to the front-end electronics are presentedComment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589