Search results for "Structural engineering"
showing 10 items of 1998 documents
Simulation investigations of the position of Fatigue Fracture Plane in materials with biaxial loads
1989
In the paper three methods of determination of the expected fatigue fracture plane position under random triaxial stress state have been presented. They are: weight function method, variance method and damage cumulation method. The weight function method for biaxial cyclic loadings has been analysed with digital simulation. The fatigue fracture plane position has been determined with mean values of the direction cosines of principal stress axes. Averaging has been done at angle values with use of weights. Eleven various weights have been presented and their usability has been analysed on the basis of experimental results obtained by Rotvel, and Nishihara-Kawamoto. The weights with good agre…
Spatial and temporal distribution of SARS-CoV-2 diversity circulating in wastewater
2022
Wastewater-based epidemiology (WBE) has proven to be an effective tool for epidemiological surveillance of SARS-CoV-2 during the current COVID-19 pandemic. Furthermore, combining WBE together with high-throughput sequencing techniques can be useful for the analysis of SARS-CoV-2 viral diversity present in a given sample. The present study focuses on the genomic analysis of SARS-CoV-2 in 76 sewage samples collected during the three epidemiological waves that occurred in Spain from 14 wastewater treatment plants distributed throughout the country. The results obtained demonstrate that the metagenomic analysis of SARS-CoV-2 in wastewater allows the detection of mutations that define the B.1.1.…
Vehicle routing problems with drones equipped with multi-package payload compartments
2022
The vehicle routing problem with drones (VRP-D) consists of designing combined truck-drone routes and schedules to serve a set of customers with specific requests and time constraints. In this paper, VRP-D is extended to include a fleet of drones equipped with multi-package payload compartments to serve more customers on a single trip. Moreover, a drone can return to a truck, different from the one from which it started, to swap its depleted battery and/or to pick up more packages. This problem, denoted as VRP-D equipped with multi-package payload compartments (VRP-D-MC), aims to maximize total profit. In this work, an adaptive multi-start simulated annealing (AMS-SA) metaheuristic algorith…
Using very high resolution (VHR) imagery within a GEOBIA framework for gully mapping: an application to the Calhoun Critical Zone Observatory
2019
AbstractGully erosion is a form of accelerated erosion that may affect soil productivity, restrict land use, and lead to an increase of risk to infrastructure. An accurate mapping of these landforms can be difficult because of the presence of dense canopy and/or the wide spatial extent of some gullies. Even where possible, mapping of gullies through conventional field surveying can be an intensive and expensive activity. The recent widespread availability of very high resolution (VHR) imagery has led to a remarkable growth in the availability of terrain information, thus providing a basis for the development of new methodologies for analyzing Earth's surfaces. This work aims to develop a ge…
SARS-CoV-2 RNA in wastewater anticipated COVID-19 occurrence in a low prevalence area
2020
Preprint disponible en http://hdl.handle.net/10261/209125
An equivalent single-layer model for magnetoelectroelastic multilayered plate dynamics
2012
Abstract An equivalent single-layer model for the dynamic analysis of magnetoelectroelastic laminated plates is presented. The electric and magnetic fields are assumed to be quasi-static and the first-order shear deformation theory is used. The formulation of the model provides for a preliminary fulfillment of the electro-magnetic governing equations, which allows to determine the electric and magnetic potential as functions of the mechanical variables. Then, by using this result, the equations of motion are written leading to the problem governing equations. They involve the same terms of the elastic dynamic problem weighted by effective stiffness coefficients, which take the magneto-elect…
Semiactive vibration control of offshore wind turbine towers with tuned liquid column dampers using H<inf>&#x221E;</inf> output feedb…
2010
This short paper addresses the problem of vibration in wind turbine towers. These structures are subject to winds and waves causing undesirable vibrations that affect the structure integrity and system performance. In order to mitigate the vibrations of the tower, a controllable tuned liquid column damper is placed on its top. We propose the use of H ∞ control techniques to formulate a control law. Furthermore, the controller uses output feedback to avoid the dependence on the knowledge of the states of the system. Simulation results illustrate the design procedure proposed in this paper.
Monitoring and Diagnosis of Failures in Squirrel-Cage Induction Motors Due to Cracked or Broken Bars
2011
In this paper three diagnostic procedures, based on on the vibration, current and instantaneous power monitoring for the detection and monitoring of incipient faults as cracks or bar breaks on squirrel cage motors are briefly reminded. The experimental investigations, carried out at the SDESLab (Sustainable Development Energy Savings Laboratory) of the University of Palermo in order to underline merits and drawbacks of the methods applied to the same die cast squirrel cage induction motor, are presented. The results of the investigations confirmed the effectiveness of the diagnostic procedures here considered.
Work-Related Stress from Whole-Body Vibration
1986
During the last 10 years, many field experiments have been carried out in various places of work. Vibration has been measured in buildings, in vehicles, and on ships. These data are currently being compiled (Dupuis and Hartung 1982) to be fed into the vibration data bank at the BIA.
Three dimensional numerical simulation of wind driven flows in closed channels and basins
2008
In the paper, a fully 3D finite-volume numerical model is developed and employed for the prediction of wind-induced flows in a regular channel and in a square basin with a complex bathymetry. Numerical results are compared with laboratory experiments.Numerical tests are then performed to investigate whether simplifying assumptions about the pressure distribution and the turbulente stresses representation can be employed in the simulation of wind-driven flows. The hydrostatic pressure assumption, resulting in the use of “quasi-3D” models, proved to be reasonably acceptable in order to obtain the vertical profile of the streamwise velocity component away from the boundaries. The quasi-3D mode…