Ion backflow studies with a triple-GEM stack with increasing hole pitch

Gas Electron Multipliers have undergone a very consistent development since their invention in 1997. Their production procedures have been tuned in such a way that nowadays it is possible to produce foils with areas of the order of the square meter that can operate at a reasonable gain, uniform over large areas and with a good stability in what concerns electrical discharges. For the third run of LHC, they will be included in the CMS and ALICE experiments after significant upgrades of the detectors, confirming that these structures are suitable for very large experiments. In the special case of Time Projection Chambers, the ion backflow and the energy resolution are sensitive issues that must be addressed and the GEM has shown to be able to deal with both of them. In this work, a stack of three GEMs with different pitches has been studied as a possible future approach for ion-backflow suppression to be used in TPCs and other detection concepts. With this approach, an ion backflow of 1 % with an energy resolution of 12 % at 5.9 keV has been achieved with the detector operating in an Ar/CO2 (90/10) mixture at a gain of ~ 2000.Comment: 15 pages, 11 figure

STUDY OF THE INFLUENCE OF THE DIAMETER OF MODIFIED TOOLS WITH INTERNAL COOLING CHANNELS UNDER DIFFERENT THERMAL FLOWS

In this work, the effect on heat generation at the chip-machine tool interface was studied by varying the diameter of internal grooves of a tool for the turning process. This tool is modified with internal channels that circulate water as a coolant through a closed system. As an output parameter, the maximum cutting temperature at the chip-tool interface was studied. The input parameters were the thermal flux present at the chip-tool interface and the diameter of the internal channels present in the cutting tool. All the analysis of variation of the internal channels of the tools and also of the thermal flow exerted on the chip-tool interface were carried out using the finite element method by the Ansys® Workbench 19.2 software. The main one was that the variation in the diameter of the tool's internal grooves does not expressly impact the machining specifications

Dressing approach to the nonvanishing boundary value problem for the AKNS hierarchy

We propose an approach to the nonvanishing boundary value problem for integrable hierarchies based on the dressing method. Then we apply the method to the AKNS hierarchy. The solutions are found by introducing appropriate vertex operators that takes into account the boundary conditions.Comment: Published version Proc. Quantum Theory and Symmetries 7 (QTS7)(Prague, Czech Republic, 2011

Editorial: Women in biofilms vol. II

Editorial on the Research Topic Women in biofilms vol. II(undefined)info:eu-repo/semantics/publishedVersio

EVALUATION OF MECHANICAL RESISTANCE BY THE FINITE ELEMENTS METHOD OF A MACHINING TOOL WITH INTERNAL COOLING CHANNELS

In this work, the strength of machining hardware for the modified turning process with internal channels that circulates water as a coolant through a closed system was studied. As output parameters, the mechanical strength at the cutting edge and in the grooves was studied. In addition, input parameters were considered different force and thermal flow conditions generated in the tool's cutting edge. All analyzes performed: Influence of temperature on tool stress, comparison of the maximum stresses in the tool channels with the cutting edge, and the influence of coolant stress in the internal channels were performed using the finite element method by the Ansys® Workbench software 19.2. The main conclusions were that the parameter that most influences the tension exerted on the tools is the force and that, according to the force exerted, the tool will not resist the tension efforts.   

Entanglement entropy and entanglement witnesses in models of strongly interacting low-dimensional fermions

We calculate the entanglement entropy of strongly correlated low-dimensional fermions in metallic, superfluid and antiferromagnetic insulating phases. The entanglement entropy reflects the degrees of freedom available in each phase for storing and processing information, but is found not to be a state function in the thermodynamic sense. The role of critical points, smooth crossovers and Hilbert space restrictions in shaping the dependence of the entanglement entropy on the system parameters is illustrated for metallic, insulating and superfluid systems. The dependence of the spin susceptibility on entanglement in antiferromagnetic insulators is obtained quantitatively. The opening of spin gaps in antiferromagnetic insulators is associated with enhanced entanglement near quantum critical points.Comment: 5 pages, 5 figures, accepted by PR