Search results for " equivalent"
showing 10 items of 172 documents
Rigorous Multimode Equivalent Network Representation of Multilayer Planar Circuits
2018
The objective of this paper is to extend the use of the Multimode Equivalent Network formulation, originally developed to analyze waveguide junctions, to the analysis of planar circuits that include arbitrary rectangular printed, zero thickness metallizations together with internal and external ports in the transverse plane. The theoretical derivations lead to an accurate and computationally efficient tool for the analysis of boxed, multilayer microwave printed circuits. In addition to theory, the tool developed is used here to analyze two practical examples: a dual-bandpass and a 4-pole bandpass boxed microstrip filters. Good agreement with respect to commercial software tools and measurem…
A model for multilayered beams undergoing end loads
2013
A formulation for layered beams undergoing end loads, namely axial, shear and bending actions, is developed and presented in this paper. A layer-wise kinematical model is first derived so that the point-wise balance relationships are fulfilled at the layer level. Successively, by enforcing the interface continuity conditions and taking the traction–free conditions on the top and bottom surfaces of the laminate into account, the layer-wise kinematical quantities are written in terms of generalized kinematical variables representative of the beam displacements field. The beam problem is then formulated in terms of these generalized variables leading to a model that shows the positive characte…
A Theory of Laminated Beams Subjected to Axial, Bending and Shear Load
2013
A theory of laminated beams subjected to axial, bending and shear loads is presented in this paper. The kinematical model employed to describe the laminated beam displacement field is layer-wise in nature. Moreover it is such that the equilibrium equations and the continuity of the stress components at plies interfaces are satisfied. By using the whole set of interface continuity conditions in conjunction with the traction –free conditions on the beam top and bottom surfaces the layer-wise kinematical quantities are written in terms of the mechanical primary variables pertaining to one layer only, which are then expressed in terms of the laminated generalized displacements. The solution for…
Passenger Car Equivalents for Heavy Vehicles at Roundabouts. a Synthesis Review
2019
Passenger Car Equivalents (PCEs in the following) are used to transform a mixed fleet of vehicles into a fleet of equivalent passenger cars and to analyze capacity and level-of-service of roads and intersections. Most roundabouts guidelines propose constant values for PCEs but a single PCE value can result improper under heterogeneous traffic conditions. PCEs should be vary with traffic and road conditions and consequently PCEs applied to undersaturated traffic conditions can overestimate the heavy vehicle effect or be not sensitive to the traffic level or characteristics of heavy vehicles. Compared to other at-grade intersections, the interaction between the operational performances of the…
Estimation of Passenger Car Equivalents for Two-Lane and Turbo Roundabouts Using AIMSUN
2020
The paper addresses issues related to Passenger Car Equivalents (PCEs) at roundabouts. Compared to other road units, the curvilinear elements of roundabout geometric design may impose greater constraints on vehicular trajectories and have a significant effect on the swept envelope of heavy vehicles. Specifically, the aim of the paper is to present the methodological approach which used traffic microsimulation to estimate PCEs. Focus is made on a case study which considered the conversion of a two-lane roundabout into a basic turbo roundabout with comparable size. Empirical capacity functions for both roundabouts were derived as target values to which simulated capacities by lane were compar…
Improving angle stability by switching shunt reactors in mixed overhead cable lines. An Italian 400 kV case study
2019
Stringent environmental constraints make the construction of new transmission overhead lines more and more difficult. Alternatively, today it is possible to use cable lines for high (HV) and extra-high (EHV) voltage systems. The configuration of the so-called mixed lines can create some problems in the operation of the electrical system, both during steady-state and transient conditions. In particular, the system stability is one of the main concerns when analyzing the dynamic response of power systems. In this paper, the study of angular stability of a system containing a mixed line is presented: a specific control logic applied to the shunt reactors of the mixed line is proposed as improv…
Prediction of the out-of-plane response of infilled frames under seismic loads by a new fiber-section macro-model
2016
This chapter suggests that an extension of the capability of the traditional inplane macro-models to capture the simultaneous in-plane and Out-Of-Plane (OOP) response of infills. A new simplified macro-model for the assessment of both in plane and out-of-plane responses of infilled frames was developed and validated. The possibility to simulate the arching action is achieved by using distributed plasticity fiber-section elements, able to directly account for the coupling between axial load and bending moment. The arching action is explicitly introduced by the use of fiber-section beam-column elements, which can model the coupling between axial-load and bending moment. The model presented is…
Encapsulation of Alcohol Dehydrogenase in Mannitol by Spray Drying
2014
The retention of the enzyme activity of alcohol dehydrogenase (ADH) has been studied in various drying processes such as spray drying. The aim of this study is to encapsulate ADH in mannitol, either with or without additive in order to limit the thermal denaturation of the enzyme during the drying process. The retention of ADH activity was investigated at different drying temperatures. When mannitol was used, the encapsulated ADH was found inactive in all the dried powders. This is presumably due to the quick crystallization of mannitol during spray drying that resulted in the impairment of enzyme protection ability in comparison to its amorphous form. Maltodextin (dextrose equivalent = 11)…
Are the Recommended Dietary Allowances for Vitamins Appropriate for Elderly People?
2015
Background: An adequate vitamin intake is essential for a good nutritional status, especially in older women, who are more sensitive to nutritional deficiencies. The American, European and Italian Recommended Dietary Allowances (RDAs) derive mainly from studies on adults, and it is not clear whether they also apply to elderly people. Comparing the RDAs with the actual vitamin intake of a group of healthy older women could help to clarify the real needs of elderly people. Objective: Our aim was to compare the American, European, and Italian RDAs with the actual vitamin intake of a group of healthy older women. Design: This was a cross-sectional study. Participants: The study included 286 hea…
Gradual caldera collapse at Bardarbunga volcano, Iceland, regulated by lateral magma outflow
2016
Large volcanic eruptions on Earth commonly occur with a collapse of the roof of a crustal magma reservoir, forming a caldera. Only a few such collapses occur per century, and the lack of detailed observations has obscured insight into the mechanical interplay between collapse and eruption.We usemultiparameter geophysical and geochemical data to show that the 110-square kilometer and 65-meter-deep collapse of Bárdarbunga caldera in 2014–2015 was initiated through withdrawal of magma, and lateral migration through a 48-kilometers-long dike, from a 12-kilometers deep reservoir. Interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurfac…