Search results for "CONSTRUCTION"
showing 10 items of 2670 documents
Head, chest and femur injury in teenage pedestrian–SUV crash; mass influence on the speeds
2018
This work studies the teenage pedestrian–sport utility vehicle (SUV) crash; injury to the vital parts of the body, such as the head and chest, and to the femur is evaluated. More advanced injury criteria are applied, as provided in the rules. The multibody technique is applied by making use of SimWise software and of the teenager anthropomorphic model, the use of which is now consolidated. Head injury criterion (HIC) is used for the head, thoracic trauma index (TTI) criterion for the thorax in the case of side impact and 3 ms criterion in the case of frontal impact, while the force criterion is used for the femur. Both the TTI and femur load evaluation require non-substantial modifications…
Pedicled Flaps for Anterior Chest Wall Reconstruction
2020
Pedicled local or regional flaps are the main reconstructive tool for chest wall defects. Muscle or musculocutaneous flaps are most commonly used, with the latissimus dorsi and the pectoralis major being the workhorse flaps. However, perforator flaps have recently affirmed even for reconstruction of complex defects. A thorough knowledge of the vascular anatomy of the thorax and of the patient’s medical history is essential for selecting the best reconstructive option. The defect location, size, and depth as well as previous surgeries in the same area are the main issues affecting the reconstructive choices.
Experimental Investigation of the Shear Response of Precast Steel-Concrete Trussed Beams
2017
The results of an experimental campaign of three-point bending tests on precast composite beams, named hybrid steel-trussed concrete beams (HSTCBs), are provided. HSTCBs are typically constituted by a precast steel truss embedded in a block of concrete cast in place. Two series of specimens were manufactured, designed such that shear failure would occur, and tested under positive and negative bending moment. The experimental results obtained showed that fragile shear failure occurred in almost all cases, evidencing the crisis of the compressed concrete strut involved in the collapse mechanism. Yielding of the steel members provided ductility to the system, especially in those cases in which…
Stressing Sequence for Hanger Replacement of Tied-Arch Bridges with Rigid Bars
2022
The construction of bridges with suspenders, such as cable-stayed or tied-arch bridges, needs deep study of the prestressing forces to be applied to stays or hangers in all stages, depending on the construction technique adopted. In these cases, the main issue is the determination of the initial forces and optimization of the prestressing system in terms of stressing values and sequence. When the bridge is already built and suspenders have to be replaced for maintenance, a different problem has to be faced by the engineer, because the sequence of replacements and the values of the axial stresses depend very much on the service conditions of the bridge and on its historical evolution from co…
Tomographic diagnostics of high-frequency electrodeless lamps in argon–mercury mixtures
2006
Tomographic reconstruction of spatial profiles of the mercury atom density in the excited state 7 3S1 in high-frequency electrodeless lamps (HFELs) has been performed. The measurements of the Hg 546.1 nm line emission intensity have been made for the HFELs in argon–mercury mixture depending on the operation regime with different cold spot temperatures in the range 31–98 °C. The maximum entropy-based algorithm was applied for the reconstruction of local emission coefficients from the integrated intensities. The emission coefficients are directly related to the local values of the mercury atom density in the excited state 7 3S1, the upper state of the 546.1 nm transition. Such an investigatio…
Intrusion of nonwetting liquid in paper
2007
The saturation curve of a sample of paper board was measured with mercury-intrusion porosimetry, and the three-dimensional structure of its pore space was determined by x-ray tomographic imaging. Ab initio numerical simulation of intrusion on the tomographic reconstruction, based on the lattice-Boltzmann method, was in excellent agreement with the measured saturation curve. A numerical invasion-percolation simulation in the same tomographic reconstruction showed good agreement with the lattice-Boltzmann simulation. The access function of the sample, determined from the saturation curve and the pore-throat distribution determined from the tomographic reconstruction, indicated that the ink-bo…
Discrete Tomography Reconstruction Through a New Memetic Algorithm
2008
Discrete tomography is a particular case of computerized tomography that deals with the reconstruction of objects made of just one homogeneous material, where it is sometimes possible to reduce the number of projections to no more than four. Most methods for standard computerized tomography cannot be applied in the former case and ad hoc techniques must be developed to handle so few projections.
Blind Radio Tomography
2018
From the attenuation measurements collected by a network of spatially distributed sensors, radio tomography constructs spatial loss fields (SLFs) that quantify absorption of radiofrequency waves at each location. These SLFs can be used for interference prediction in (possibly cognitive) wireless communication networks, for environmental monitoring or intrusion detection in surveillance applications, for through-the-wall imaging, for survivor localization after earthquakes or fires, etc. The cornerstone of radio tomography is to model attenuation as the bidimensional integral of the SLF of interest scaled by a weight function. Unfortunately, existing approaches (i) rely on heuristic assumpti…
Applications and development of acoustic and microwave atomic force microscopy for high resolution tomography analysis
2016
The atomic force microscope (AFM) is a powerful tool for the characterization of organic and inorganic materials of interest in physics, biology and metallurgy. However, conventional scanning probe microscopy techniques are limited to the probing surface properties, while the subsurface analysis remains difficult beyond nanoindentation methods. Thus, the present thesis is focused on two novel complementary scanning probe techniques for high-resolution volumetric investigation that were develop to tackle this persisting challenge in nanometrology.The first technique considered, called Mode Synthesizing Atomic Force Microscopy (MSAFM), has been exploited in collaboration with Dr. Laurene Teta…
A Lightweight Network Discovery Algorithm for Resource-constrained IoT Devices
2019
Although quite simple, existing protocols for the IoT suffer from the inflexibility of centralized infrastructures and require several configuration stages. The implementation of these protocols is often prohibitive on resource-constrained devices. In this work, we propose a distributed lightweight implementation of network discovery for simple IoT devices. Our approach is based on the exchange of symbolic executable code among nodes. Based on this abstraction, we propose an algorithm that makes even IoT resource-constrained nodes able to construct the network topology graph incrementally and without any a priori information about device positioning and presence. The minimal set of executab…