The use of transverse connectors as reinforcement of multi-leaf walls

The need for new retrofitting techniques is the consequence of an increasing interest in the conservation of historic construction. The global behavior of a stone masonry structure is often governed by the level of connection between masonry wall leaves and the overall quality of the masonry material. This paper presents the results of an investigation carried out on site and in the laboratory on multi-leaf stone masonry panels strengthened using stainless steel rod inserted in a grouted fabric sleeve. The aim is to increase the collaboration between weakly connected masonry leaves. Pull-out tests were conducted on site on full-scale stone masonry wall panels, with the aim of studying the force required to pull out a connector under uniaxial tension. Several wall panels were assembled in the laboratory using solid calcareous stones and weak mortar and the effectiveness of the connectors was tested in shear and compression on both virgin and damaged panels. The experimental tests allowed the analysis of the behavior of the multi-leaf panels. Experimental results show that a substantial improvement of the wall panels' mechanical behavior can be achieved by applying transverse connectors

Repairing brickwork panels using titanium rods embedded in the mortar joints

This paper investigates repairing brickwork masonry walls using smooth titanium rods. Firstly, numerical analyses were carried out following a detailed micro-modelling strategy and then an experimental research program was undertaken in the laboratory. Solid clay brick specimens were initially tested, without strengthening, and subsequently re-tested, after repair, using titanium rods. Rods were embedded into the horizontal joints using an epoxy paste or a cement mortar. A double-sided repair was considered. Shear tests were carried out on four brickwork panels, under diagonal loading. The mechanism by which the diagonal shear load was carried was analyzed, varying from the uncracked state, to the final, cracked state, for both control and repaired wall panels. The results demonstrate that it is partially possible to restore the panels’ original in-plane shear capacity by embedding titanium rods into the horizontal bed joints using the epoxy paste. The experimental results were used to evaluate the effectiveness of the titanium repair, and recommendations are made to allow the test data to be used in the design procedure of cracked masonry structures. Unsatisfactory test results were recorded for panels repaired using a cement mortar

On the interplay of computation and memory regulation in multicore real-time systems

The ever-increasing demand for high performance in the time-critical embedded domain has pushed the adoption of powerful yet unpredictable heterogeneous Systems-on-a-Chip. The shared memory subsystem, which is known to be a major source of unpredictability, has been extensively studied, and many mitigation techniques have been proposed. Among them, performance-counter-based regulation techniques have seen widespread adoption. However, the problem of combining performance-based regulation with time-domain isolation has not received enough attention. In this article, we discuss our current work-in-progress on SHCReg (Software Hardware Co-design Regulator). First, we assess the limitations and benefits of combined CPU and memory budgeting. Next, we outline a full-stack hardware/software codesign architecture that aims at improving the interplay between CPU and memory isolation for mixed-criticality tasks running on the same core.National Science FoundationAccepted manuscrip

RobotPerf: An Open-Source, Vendor-Agnostic, Benchmarking Suite for Evaluating Robotics Computing System Performance

We introduce RobotPerf, a vendor-agnostic benchmarking suite designed to evaluate robotics computing performance across a diverse range of hardware platforms using ROS 2 as its common baseline. The suite encompasses ROS 2 packages covering the full robotics pipeline and integrates two distinct benchmarking approaches: black-box testing, which measures performance by eliminating upper layers and replacing them with a test application, and grey-box testing, an application-specific measure that observes internal system states with minimal interference. Our benchmarking framework provides ready-to-use tools and is easily adaptable for the assessment of custom ROS 2 computational graphs. Drawing from the knowledge of leading robot architects and system architecture experts, RobotPerf establishes a standardized approach to robotics benchmarking. As an open-source initiative, RobotPerf remains committed to evolving with community input to advance the future of hardware-accelerated robotics

Commissioning of the PADME experiment with a positron beam

The PADME experiment is designed to search for a hypothetical dark photon A' produced in positron-electron annihilation using a bunched positron beam at the Beam Test Facility of the INFN Laboratori Nazionali di Frascati. The expected sensitivity to the A'-photon mixing parameter ϵ is 10-3, for A' mass ≤ 23.5 MeV/c 2 after collecting ∼1013 positrons-on-target. This paper presents the PADME detector status after commissioning in July 2019. In addition, the software algorithms employed to reconstruct physics objects, such as photons and charged particles, and the calibration procedures adopted are illustrated in detail. The results show that the experimental apparatus reaches the design performance, and is able to identify and measure standard electromagnetic processes, such as positron bremsstrahlung and electron-positron annihilation into two photons

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements