A mixed-mode readout Application Specific Integrated Circuit (STIC3) has been developed for high precision timing measurements with Silicon Photomultipliers (SiPM) for medical imaging and particle ...physics applications. The STiC3 is a 64-channel chip, with fully differential analog front-end for cross-talk and electronic noise immunity. The time and charge information from the SiPM signals are encrypted into two time stamps generated by integrated Time to Digital Converter (TDC) modules with 50ps time binning. The TDC data is stored in an internal memory and transferred to a PC via a 160MBit/s serial link using an 8/10 bit encoding. The chip provides an input bias tuning in a range of 0–900mV to compensate the breakdown voltage variation of individual SiPMs. The TDC jitter together with the digital part is around 37ps. A Coincidence Time Resolution (CTR) of 213.6ps FWHM has been obtained with 3.1×3.1×15m2 LYSO:Ce scintillator crystals and Hamamatsu SiPM matrices (S12643-050CN(X)). Characterization measurements with the chip and its integration into the external plate of the EndoTOFPET-US prototype are presented.
The energy resolution of a highly granular 1 m3 analogue scintillator-steel hadronic calorimeter is studied using charged pions with energies from 10 GeV to 80 GeV at the CERN SPS. The energy ...resolution for single hadrons is determined to be approximately 58%/sqrt(E/GeV}. This resolution is improved to approximately 45%/sqrt(E/GeV) with software compensation techniques. These techniques take advantage of the event-by-event information about the substructure of hadronic showers which is provided by the imaging capabilities of the calorimeter. The energy reconstruction is improved either with corrections based on the local energy density or by applying a single correction factor to the event energy sum derived from a global measure of the shower energy density. The application of the compensation algorithms to Geant4 simulations yield resolution improvements comparable to those observed for real data.
•Topology optimization of conjugate heat transfer systems.•Optimal designs obtained by multi-objective topology optimization.•Topology optimization for thermal power maximization & pressure drop ...reduction.
Topology optimization method is developed for a multi-objective function combining pressure drop reduction and thermal power maximization (incompressible flows at low to moderate Reynolds numbers). Innovative optimal designs are obtained, discussed and presented on a Pareto-frontier. The numerical developments (continuous adjoint technique) have been conducted inside an open source CFD platform via the finite volume method. Comparisons have been presented with an optimal design obtained by a Lattice Boltzmann Method from the literature. Finally, this contribution presents and discuss several detailed numerical vitrification steps which are essential to be conducted in topology optimization method when applied with multi-objective functions.
•Experimental thermal measurements of optimal heat sinks.•Experimental heat sinks obtained by topology optimization.•Bi-material distribution in volume-to-point heat evacuation.
For optimal tree-like ...heat conductive structures obtained numerically by topology optimization (TO), few experimental investigations exist in the literature to author’s knowledge. In this context, the present study deals with an experimental investigation of tree-like structures obtained by topology optimization (known also by bi-material volume-to-point problems). For a volume (of lower conductivity material) that is continuously generating heat, TO predicts tree-like structures (of higher conductivity material) to evacuate efficiently the amount of heat being generated. Experimental measurements were carried out on two tree-like structures using infrared thermography in order to test the validity of the developed numerical topology optimization approach. It is found that the experimental thermal measurements are in good agreement with numerical data obtained by TO, which was developed in this work by coupling the method of moving asymptotes (MMA) as optimization algorithm to the solid isotropic material with penalization (SIMP) as a bi-material distribution technique.
Open industrial yards of granular materials can result in a large amount of particles emitted into the atmosphere due to wind erosion, offering risks to the environment and to the human health. It is ...important to estimate these emissions in order to manage dust control techniques and environmental polices requirements. There are several studies on particles emission from stockpiles surfaces, but there are few studies considering the re-emission that can occur from the regions around the stockpiles. Therefore, the present work aims to investigate the influence of the fluid flow complex structures near the ground region surrounding stockpiles and how they can influence the re-emission of particles. Experimental work using the oil-film technique and numerical simulations of the flow over one and two successive stockpiles oriented 30°, 60° and 90° to the incoming flow were performed. The results showed that a stockpile or successive stockpiles oriented 60° must be avoided in industrial sites as they promote high values of re-emitted mass around the piles. On the other hand, piles oriented 90° to the incoming flow showed the lowest re-emission potential for the surroundings. Finally, the gap between successive stockpiles showed insignificant influence on the emission estimates.
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