Search results for "Component"
showing 10 items of 1682 documents
Charles LeGeyt Fortescue and the method of symmetrical components
2002
The author gives a brief review of the life and work of Charles LeGeyt Fortescue with particular reference to his 1918 paper on the "Method of Symmetrical Co-Ordinates Applied to the Solution of Polyphase Networks" which grew out of his investigations of problems related to railway electrification, which began in 1913. As a postlude to the author's article, the paper presents Fortescue's own writing on the topic of symmetrical components, which he included in a document he produced on 8 October 1934, titled "High Points in My Career".
Embedding “roadside equipment” in the environmental assessment of transportation system: the case of safety barriers
2014
The work arises from the consideration that the environmental impact of a road cannot be limited to the analysis of its constituent materials, even if correctly analyzed in their life cycle. In fact, a given road not only consists of the pavement and subgrade, but also includes several different components and accessories (e.g., road marking, drainages, safety barriers, etc.) that contribute to set a road infrastructure in operative condition. As a matter of fact, only limited attention has been paid in the scientific literature to roadside components, unlike pavement and traffic flow. In the present work, the environmental burden of one of these components, i.e., the safety barrier has bee…
Use of finite element models for estimating thermal performance of façade-integrated solar thermal collectors
2016
Abstract Research on building-integrated solar thermal collectors is attracting increasingly more interest. Many efforts have been focused at the design level for obtaining specific building-orientated products, but there is a significant lack of standardised methods for evaluating how the efficiency of solar collectors changes when a wall is an integral part of the solar component itself. Generally speaking, experimental tests on integrated components are not easy to realise and are, in any case, expensive in terms of time and money. Physical and numerical methods can be utilised, but at the moment, there is no common approach. The present work addresses a method for the calculation of a b…
RF Breakdown Prediction for Microwave Passive Components in Multi-carrier Operation
2010
This work addresses the multipactor problem for multi-carrier operation inside rectangular waveguide based devices, by means of numerical simulations of the electron trajectories and multiplication inside the structure. Accurate field calculation and taking into account space charge effects are mandatory. For this, a PIC-FDTD method has been employed. As a result, novel software has been implemented offering the possibility of predicting multipactor in multicarrier systems for a wide variety of situations. Simulation results show that multipactor can occur even for short pulse durations if an inter-period charge accumulation is present.
An imprecise Fault Tree Analysis for the estimation of the Rate of OCcurrence Of Failure (ROCOF)
2013
Abstract The paper proposes an imprecise Fault Tree Analysis in order to characterize systems affected by the lack of reliability data. Differently from other research works, the paper introduces a classification of basic events into two categories, namely Initiators and Enablers . Actually, in real industrial systems some events refer to component failures or process parameter deviations from normal operating conditions ( Initiators ), whereas others refer to the functioning of safety barriers to be activated on demand ( Enablers ). As a consequence, the output parameter of interest is not the classical probability of occurrence of the top event, but its Rate of OCcurrence (ROCOF) over a s…
Geometrical analysis of self-compensating suspension systems for railcar engineering
2002
The present analysis addresses several passive tilt systems for railroad cars aiming to compensate for the cart deficiency on curved tracks. To this end, the virtual centre of suspension must be located as close as possible to the longitudinal plane of symmetry of the coach, above the mass centre level for stability reasons. On the one hand, pantograph or Peaucellier's mechanisms may achieve the correct self-compensation. On the other hand, simpler articulated systems yield the desired goal with an excellent approximation. For example, selective algorithms can be applied for designing eight-link mechanisms, to be optimized thereafter by some method of the gradient type, minimizing the mean…
Induction Heating Technology and Its Applications: Past Developments, Current Technology, and Future Challenges
2013
International audience; Induction heating technology is nowadays the heating technology of choice in many industrial, domestic, and medical applications due to its advantages regarding efficiency, fast heating, safety, cleanness, and accurate control. Advances in key technologies, i.e. power electronics, control techniques, and magnetic component design, have allowed the development of highly reliable and cost-effective systems, making this technology readily available and ubiquitous. This papers reviews induction heating technology summarizing the main milestones in its development, and analyzing the current state-of-art of induction heating systems in industrial, domestic and medical appl…
A Multi-Objective Approach to Optimize a Periodic Maintenance Policy
2012
The present paper proposes a multi-objective approach to find out an optimal periodic maintenance policy for a repairable and stochastically deteriorating multi-component system over a finite time horizon. The tackled problem concerns the determination of the system elements to replace at each scheduled and periodical system inspection by ensuring the simultaneous minimization of both the expected total maintenance cost and the expected global system unavailability time. It is assumed that in the case of system elements failure they are instantaneously detected and repaired by means of minimal repair actions in order to rapidly restore the system. A nonlinear integer mathematical programmi…
Scars Collaborative Telediagnosis Platform Using Adaptive Image Flow
2013
International audience; Telemedicine has been developed to allow practitioners to remotely connect with patients and with other medical staff.We propose a new system (hardware and software), named DICODERM (COllaborative DIagnosis of DERMatosis), which makes it possible to monitor the evolution of scars after the excision of a tumorous dermatosis (like melanoma). The hardware part of this system is composed of a new optical innovative probe with which two types of images can be acquired simultaneously: anatomic with a white light image and functional with a fluorescence image (using autofluorescence from the protoporphyrin within the cancer cell). The software part is composed of two compon…
The cost of green roofs disposal in a life cycle perspective: covering the gap.
2012
Abstract This study is aimed at providing a contribution in overcoming the current gap, especially in Life Cycle Costing (LCC) and Benefit – Cost (BCA) analyses, due to the lack concerning the green roof disposal costs. Therefore, we have applied to an actual extensive green roof the LCC methodology suggested by D. G. Woodward (that appears like one of the most formalized and generalizable), but we have extended the analysis to the disposal phase. This will allow a complete and proper application of the LCC methodology in order of achieving an economic accounting of this component through its life cycle. In this way, it is possible to achieve the complete evaluation of the “green roof” perf…