Search results for "bridge"
showing 10 items of 355 documents
The land bridge between Europe and Sicily over the past 40 kyrs: Timing of emersion and implications for the migration of Homo sapiens
2012
The submerged Sill in the Messina Strait, which is located at a depth of -81 m m.s.l., represents the only possibile connection between Calabria and Sicily during the last lowstand, when the sea level was at about -126 m m.s.l. This multidisciplinary research aim at documenting times and modes the bridge between Calabria and Sicily was emerged, during the last 40 ka BP. The analysis carried out on morphobathymetric, lithological and relative sea level change (both isostatic and tectonic) data allow to hypothesize the continental bridge emerged at least between 21.5 ka and 20 ka cal BP. Moreover, considering erosion processes due to very strong marine currents, it could be emerged for a long…
Assessment and strengthening of reinforced concrete bridges with half-joint deterioration
2022
Existing Niagara-type concrete cantilever bridges, which in Italy are called Gerber bridges, suffer from degradation due to reinforcement corrosion and a consequent reduced load-bearing capacity. The assessment of these structures is therefore an important part of the procedures for analyzing the state of existing bridges and any interventions required for their retrofitting. In particular, safety against failure of the half-joint must be evaluated with respect to the behavior of the entire bridge and its state of conservation, determining what the conditions are that lead to failure, in terms of loads, state of stress, and possibly cracking state. This evaluation has to be carried out cons…
Crystal structure of tricarbonyl(μ-diphenylphosphido-κ2P:P)(methyldiphenylsilyl-κSi)bis(triphenylphosphane-κP)iron(II)platinum(0)(Fe—Pt)
2015
The title compound belongs to the large family of heterodinuclear phosphide-bridged complexes. The Fe—Pt bond is of 2.7738 (4) Å and there is an unprecedented arrangement of the silyl ligand in a trans-position with respect to the metal–metal vector in the family of phosphide-bridged iron–platinum heterobimetallics.
The Measurement of Large Strains Using Electrical Resistance Strain Gages
2011
It is well known that in the range of large strains, the electrical resistance strain gages have a nonlinear behavior, that is the variation of electrical resistance is a nonlinear function of the strain applied to the strain gage, which means that the gage factor K is not constant. Also, the Wheatstone bridge has a nonlinear behavior at large strains. Usually the two nonlinearities have opposite effects, therefore the overall nonlinearity decreases. This article presents an overview of the behavior of strain gages subject to large strains and of the corrections to account for nonlinearities of both the strain gage and the Wheatstone bridge.
On the use of unmanned aerial systems for environmental monitoring
2018
[EN] Environmental monitoring plays a central role in diagnosing climate and management impacts on natural and agricultural systems; enhancing the understanding of hydrological processes; optimizing the allocation and distribution of water resources; and assessing, forecasting, and even preventing natural disasters. Nowadays, most monitoring and data collection systems are based upon a combination of ground-based measurements, manned airborne sensors, and satellite observations. These data are utilized in describing both small-and large-scale processes, but have spatiotemporal constraints inherent to each respective collection system. Bridging the unique spatial and temporal divides that li…
Design and Realization of a Bidirectional Full Bridge Converter with Improved Modulation Strategies
2020
In this paper a Full-Bridge Converter (FBC) for bidirectional power transfer is presented. The proposed FBC is an isolated DC-DC bidirectional converter, connected to a double voltage source&mdash
Intentions of early retirement and continuing to work among middle-aged and older employees
2009
The purpose of this study is to investigate personal, health, work, and work-related psychological factors in association with employee intentions of early retirement and continuing to work after retirement in the form of bridge employment. In addition, the study aims to further our understanding of what motivates older employees by investigating age-related differences in employee reward preferences. The study draws upon several theoretical perspectives, including continuity theory, the life course perspective, theories on motivation, and the meaning of work for older employees. Survey data from three individual research projects are used in this study - age management studies consisting o…
Investigation about selective harmonic elimination in unbalanced multilevel inverters
2022
In this paper 5 and 7 levels cascaded H-bridges inverters are considered, feeding by unequal dc voltage sources. The effect of these unbalancing operation is examined concerning harmonic analysis and total harmonic distortion of the output voltages. The system of equations, obtained by the expansion in the Fourier series of phase output voltage, is solved by applying a method of graphic solution that allows obtaining the switching angles able to eliminate the lower order harmonics.
Efectos de la vibración sobre la actividad del rectus abdominis y sobre la transmisión de aceleraciones durante la realización de un puente frontal. …
2012
Durante las dos ultimas decadas se ha incrementado notablemente la utilizacion de la vibracion como medio complementario de ejercicio fisico. La literatura cientifica muestra distintos efectos positivos, aunque la mayor parte de ensayos se han centrado en el analisis del ejercicio de squat. El objetivo del presente estudio fue analizar la actividad muscular del rectus abdominis y la transmision de la vibracion en el cuerpo humano durante la realizacion de un puente frontal sobre una plataforma vibratoria oscilante vibrando a diferentes frecuencias (5, 16, 20 Hz) y a una amplitud constante (3 mm). Las aceleraciones maximas en la cabeza (ejes X, Y, Z) y la actividad electromiografica media de…
Optimizing artificial neural networks for the evaluation of asphalt pavement structural performance
2019
Artificial Neural Networks represent useful tools for several engineering issues. Although they were adopted in several pavement-engineering problems for performance evaluation, their application on pavement structural performance evaluation appears to be remarkable. It is conceivable that defining a proper Artificial Neural Network for estimating structural performance in asphalt pavements from measurements performed through quick and economic surveys produces significant savings for road agencies and improves maintenance planning. However, the architecture of such an Artificial Neural Network must be optimised, to improve the final accuracy and provide a reliable technique for enriching d…