We present the results of our performance studies of the upgraded Cherenkov time-of-flight (ToF) detector for the AFP (ATLAS Forward Proton) project. The latest version consists of solid L-shaped fused silica bars, new customized ALD-coated micro-channel plate photomultipliers (MCP-PMTs) miniPlanacon XPM85112-S-R2D2 with an extended lifetime which operate at low gains (order of 103), and an updated construction. The improvements were aimed to increase the efficiency, the lifetime as well as the radiation hardness of the detector which has been designed to operate in high radiation areas (above 400 kGy/year). The detector was finally tested at the CERN-SPS test-beam facility (120 GeV π+ particles) in August 2021 prior to its installation at the Large Hadron Collider (LHC) at CERN. Measurements proved the detector kept its inner timing resolution of 20 ps despite the rather low gain of its photodetector and reduced optical throughput caused by inevitable changes in the detector geometry.
Stereooptics method have been successfully used in biomechanical studies of dental models. The aim of this study was to investigate, on the basis of functional deformities, the distribution of occlusal loads on the casts of a partially-edentulous mandible without and with dedicated copings. Precise measurement of strain and displacement of partially-edentulous mandibular control and experimental casts were provided by the digital image correlation method and ARAMIS software. Simulated loads ranged from 0 to 1000 N. Displacements and deformations of abutment teeth within the control cast of a partially-edentulous mandible were 0.48% for incisor without coping, 10.29% for canine without coping, and 6.64% for premolar without coping, and within the experimental cast of a partially-edentulous mandible they were 0.29% for incisor with coping, 7.007% for canine with coping, and 4.98% for premolar with coping. Wilcoxon matched pairs signed ranks sum test was not statistically significant for the majority of the examined parameters, except for the differences between deformations of teeth and copings under pressure p ≤ 0.05. When loading the abutment teeth, the distribution of strain through the remaining tooth substance is specific and various. Abutment teeth covered by protective copings are more resistant to loads.
This paper presents a part of development of a non-standard method for
testing of cylindrical test specimens for measurement of fracture properties
of pipeline materials. This method for testing of cylindrical structures
working under pressure is based on determining of fracture mechanics
parameters on SENT (Single Edge Notched Tension) specimens and new PRNT
(Pipe Ring Notched Tension) specimens. In this work, both types of specimens
required for this testing were manufactured from polyamide PA12 by using SLS
(selective laser sintering) additive manufacturing method. Testing of the
specimens is performed on the universal device for testing of mechanical
properties of materials Shimadzu, AGS-X 100 kN. The tensile testing is
accompanied by GOM Aramis 2M system, used for digital image correlation. By
using these two systems, test results are obtained for ring-shaped and SENT
specimens, including forces, displacements and fracture mechanics parameters
CMOD (Crack Mouth Opening Displacement) and CTOD-?5 (Crack Tip Opening
Displacement obtained by ?5 technique), as well as crack growth.
Repeatability of this process, along with valid result consistency,
represent the basis for further development of the new method, including the
determining of energy-based fracture mechanics parameters: J integral and
stress intensity factor.
Martial arts and fight sports are mostly based on exchanging the punches and kicks that often result with injuries of face, skull bones, and neck vertebrae. One of possibilities to reduce number of injuries in athletes who deal with martial arts is development of new materials and improvement of designs for helmets used in sport fights. In order to experimentally analyze impact forces and simulate conditions during different fight punches mechanical installment was made. Aramis system is used to measure the displacement fields and the distribution of deformations which occur on the neck over the entire analyzed area based on the correlation of digital images. On this manner better understanding of behavior of both materials and structures during the action of the impact forces and loading is obtained. This information can further be used in researches related to the development of helmets used in martial arts which would influence reduction of values of neck deformations in athletes.
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