Search results for "format"
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Innovative method to estimate state of charge of the hydride hydrogen tank: application of fuel cell electric vehicles
2021
International audience; Significant attention has been paid to metal hydrides (MH) as an environmentally friendly and safe way to store hydrogen. This technology has considerable potential for the application of embedded hydrogen storage in fuel cell electric vehicles, but its widespread application faces a major problem in terms of estimating the remaining hydrogen amount in the tank. In this work, a new method is proposed for estimating the state of charge (SoC) of the hydrogen hydride tank (HHT) by application of piezoelectric material. The idea is to cover the entire inner wall of the metal-hydride tank with a layer of piezoelectric material. During the process of hydrogen absorption, t…
Considerations Regarding the Industrial Implementation of Incremental Forming Process
2019
Incremental forming is a promising manufacturing process which allow the user to obtain sheet metal parts, in a flexible manner, without the use of a die. However, the industry is still reluctant to apply the process on an industrial scale. Several drawbacks of the process which hinder its industrial implementation are reviewed in the paper. Among them, the low accuracy of the parts and the low productivity of the process are considered. The lack of dedicated technological equipment and specific CAM software tools are also seen as major drawbacks. Moreover, the lack of any analytical tools to predict the plastic behaviour of the processed part and to predict the moment when it loses its int…
Uncovering Technological and Environmental Potentials of Aluminum Alloy Scraps Recycling Through Friction Stir Consolidation
2020
Conventional metal chips recycling processes are energy-intensive with low efficiency and permanent material losses during re-melting. Solid state recycling allows direct recycling of metal scraps into semi-finished products. It is expected that this process category would lower the environmental performance of metals recycling. Friction Stir Consolidation is a new solid-state technique taking advantage of friction heat generation and severe plastic deformation to consolidate chips into billets. In this research, the feasibility of Friction Stir Consolidation as aluminum chips recycling process is analyzed. Specifically, an experimental campaign has been carried out with varying main proces…
Application of linear friction welding for joining ultrafine grained aluminium
2020
Abstract Ultrafine grained (UFG) materials are of great potential in industry due to their enhanced mechanical strength and other promising features, such as ability to superplastic deformation or excellent corrosion resistance. Nevertheless, one of the main limitations lies in their low thermal stability, which leads to excessive grain growth at elevated temperature. It influences mainly further processes performed at high temperature, such as joining. It causes detrimental problems during conventional fusion welding, as significant grain growth is observed and therefore the advantages as a result of small average grain size disappear. Therefore, the idea of applying solid state joining pr…
The Effect of Baffles on Heat Transfer
2019
For a long time technicians and engineers have used geometric changes of objects for the purpose of enhancement of heat transfer. The discovery and use of nanofluids and their unique properties lead to a new revolution on the heat transfer. This paper presents the simulation of Ansis software applied to the flow tube with a constant flux, also studies the effect of baffles and the use of nano particles on heat transfer.
Decorous combinatorial lower bounds for row layout problems
2020
Abstract In this paper we consider the Double-Row Facility Layout Problem (DRFLP). Given a set of departments and pairwise transport weights between them the DRFLP asks for a non-overlapping arrangement of the departments along both sides of a common path such that the weighted sum of the center-to-center distances between the departments is minimized. Despite its broad applicability in factory planning, only small instances can be solved to optimality in reasonable time. Apart from this even deriving good lower bounds using existing integer programming formulations and branch-and-cut methods is a challenging problem. We focus here on deriving combinatorial lower bounds which can be compute…
Mathematical models for a cutting problem in the glass manufacturing industry
2021
Abstract The glass cutting problem proposed for the ROADEF 2018 challenge is a two-dimensional, three-stage guillotine cutting process, with an additional cut to obtain pieces in some specific situations. However, it is not a standard problem because it includes specific constraints. The sheets produced in the glass manufacturing process have defects that make them different and have to be used in order. The pieces to be cut are grouped into subsets and the pieces from each subset must be cut in order. We approach the problem by developing and solving integer linear models. We start with the basic model, which includes the essential features of the problem, as a classical three-stage cuttin…
Forecasting portfolio returns using weighted fuzzy time series methods
2016
We propose using weighted fuzzy time series (FTS) methods to forecast the future performance of returns on portfolios. We model the uncertain parameters of the fuzzy portfolio selection models using a possibilistic interval-valued mean approach, and approximate the uncertain future return on a given portfolio by means of a trapezoidal fuzzy number. Introducing some modifications into the classical models of fuzzy time series, based on weighted operators, enables us to generate trapezoidal numbers as forecasts of the future performance of the portfolio returns. This fuzzy forecast makes it possible to approximate both the expected return and the risk of the investment through the value and a…
Optimal control of discrete-time interval type-2 fuzzy-model-based systems with D-stability constraint and control saturation
2016
This paper investigates the optimal control problem for discrete-time interval type-2 (IT2) fuzzy systems with pole constraints. An IT2 fuzzy controller is characterized by two predefined functions, and the membership functions and the premise rules of the IT2 fuzzy controller can be chosen freely. The pole assignment is considered, which is constrained in a presented disk region. Based on Lyapunov stability theory, sufficient conditions of asymptotic stability with an H ∞ performance are obtained for the discrete-time IT2 fuzzy model based (FMB) system. Based on the criterion, the desired IT2 state-feedback controller is designed to guarantee that the closed-loop system is asymptotically s…
Modeling and control of uncertain nonlinear systems
2018
A survey of the methodologies associated with the modeling and control of uncertain nonlinear systems has been given due importance in this paper. The basic criteria that highlights the work is relied on the various patterns of techniques incorporated for the solutions of fuzzy equations that corresponds to fuzzy controllability subject. The solutions which are generated by these equations are considered to be the controllers. Currently, numerical techniques have come out as superior techniques in order to solve these types of problems. The implementation of neural networks technique is contributed in the complex way of dealing the appropriate coefficients and solutions of the fuzzy systems.