Resistive Plate Chambers detectors are extensively used in several domains of Physics. In High Energy Physics, they are typically operated in avalanche mode with a high-performance gas mixture based on Tetrafluoroethane (C2H2F4), a fluorinated high Global Warming Potential greenhouse gas. The RPC EcoGas@GIF++ Collaboration has pursued an intensive R&D activity to search for new gas mixtures with low environmental impact, fulfilling the performance expected for the LHC operations as well as for future and different applications. Here, results obtained with new eco-friendly gas mixtures based on Tetrafluoropropene and carbon dioxide, even under high-irradiation conditions, will be presented. Long-term aging tests carried out at the CERN Gamma Irradiation Facility will be discussed along with their possible limits and future perspectives.
New 1,4-disubstituted pyrazoles featuring benzodioxane as the basic skeleton have been synthesized successfully through a copper-catalyzed cycloaddition reaction of alkynes with 3-arylsydnones, a process that is typically challenging using conventional methods. These newly synthesized compounds have been identified through comprehensive analysis of NMR (1H and 13C). Furthermore, the structures of 5d and 5f were resolved by single crystal X-ray diffraction (SCXRD) analysis. Both compounds crystallize in the monoclinic system in the space group C2/c. The structures were stabilized by C-H & sdot;& sdot;& sdot;O and C-H & sdot;& sdot;& sdot;N hydrogen bonds with C-H & sdot;& sdot;& sdot;pi and pi & sdot;& sdot;& sdot;pi interactions. Hirshfeld surface analysis for crystal packing indicates that the most important contributions are H & ctdot;H (40.3% 5d, 37.8% 5f), O & ctdot;H/H & ctdot;O (18.8% 5d, 21.7% 5f), and C...H/H...C (22.8% 5d, 21.8% 5f) interactions. DFT calculations were carried out for 4a-c and 5a-f using B3LYP/6-31G(d, p) methodology to predict their preferred interaction sites. Natural bond orbital (NBO) analysis was carried out to investigate the intramolecular interactions of all molecules. Through molecular docking studies, strong interactions between 1,4-disubstituted pyrazole featuring benzodioxane and the active sites of both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were observed. They were particularly notable for their affinity with key amino acid residues within the active sites. Such revelations illuminate a promising path forward, suggesting that the 1,4-disubstituted pyrazole featuring benziodioxane holds significant potential for Alzheimer's therapy.
Logicism is the thesis that mathematics can be derived from logic. In both The Principles of Mathematics and Principia Mathematica, Russell sets out to demonstrate that mathematics can be deduced from a small number of “indefinable” concepts and “primitive propositions.” But until now, little attention has been paid to the conception of mathematics induced by this logicist approach: What mathematics were the logicians seeking to reduce? How did they treat the differences between mathematical disciplines (as, for example, the differences between arithmetic, algebra, geometry, etc.)? Did they consider that the demarcations between fields within mathematics had to be derived logically, or did they consider, on the contrary, that this was unnecessary? This chapter addresses this question and shows, by examining the organization of both The Principles and Principia Mathematica, that the ambition of Russellian logicism was not only to deduce the content of mathematics but also to account for its architecture.
Since 2019 a collaboration between researchers from various institutes and experiments (i.e. ATLAS, CMS, ALICE, LHCb/SHiP and the CERN EP-DT group), has been operating several RPCs with diverse electronics, gas gap thicknesses and detector layouts at the CERN Gamma Irradiation Facility (GIF++). The studies aim at assessing the performance of RPCs when filled with new eco-friendly gas mixtures in avalanche mode and in view of evaluating possible ageing effects after long high background irradiation periods, e.g. High-Luminosity LHC phase. This challenging research is also part of a task of the European AidaInnova project. A promising eco-friendly gas identified for RPC operation is the tetrafluoruropropene (C_3H_2F_4, commercially known as HFO-1234ze) that has been studied at the CERN GIF++ in combination with different percentages of CO_2. Between the end of 2021 and 2022 several beam tests have been carried out to establish the performance of RPCs operated with such mixtures before starting the irradiation campaign for the ageing study. Results of these tests for different RPCs layouts and different gas mixtures, under increasing background rates are presented here, together with the preliminary outcome of the detector ageing tests.
