Search results for "work in process"
showing 10 items of 28 documents
Measurements and Observations in the XXI century (MOXXI) : innovation and multi-disciplinarity to sense the hydrological cycle
2018
ISI Document Delivery No.: FV7JXTimes Cited: 4Cited Reference Count: 249Tauro, Flavia Selker, John van de Giesen, Nick Abrate, Tommaso Uijlenhoet, Remko Porfiri, Maurizio Manfreda, Salvatore Caylor, Kelly Moramarco, Tommaso Benveniste, Jerome Ciraolo, Giuseppe Estes, Lyndon Domeneghetti, Alessio Perks, Matthew T. Corbari, Chiara Rabiei, Ehsan Ravazzani, Giovanni Bogena, Heye Harfouche, Antoine Brocca, Luca Maltese, Antonino Wickert, Andy Tarpanelli, Angelica Good, Stephen Alcala, Jose Manuel Lopez Petroselli, Andrea Cudennec, Christophe Blume, Theresa Hut, Rolf Grimaldi, SalvatoreTaylor & francis ltdAbingdon; To promote the advancement of novel observation techniques that may lead to new so…
Effective Linear Friction Welding Machine Redesign through Process Analysis
2014
Linear friction welding is a solid-state joining process developed for non-axisymmetric components in which the joining of the specimens is obtained through reciprocating motion and pressure. In the process, the friction forces work due to the high frequency oscillation and the pressure between the specimens is converted in thermal energy. In order to design an effective machine, relevant issues derive from the high frequency and the large inertial forces involved in the process. In this study, the authors describe the redesign of a preexisting prototypal machine for LFW processes. A machine redesign is needed when welding high resistant materials, i.e. steels or titanium alloys, with high …
Distributed intelligent control of exceptions in reconfigurable manufacturing systems
2003
In order to react to the continuous and unpredictable changes in product demand, in product variety, and in process technologies, reconfigurable manufacturing systems allow quick adjustment of production capacity and functionality by rearranging or changing their modular components. In this kind of system, operation management issues, such as exception handling policies, become more complex since correct reconfiguration strategies have to be selected. This paper explores the potential of the reconfigurability feature to be a basis for the development of new strategies to handle out-of-the-ordinary events in the production process; in particular, maintaining production flow when machine brea…
Thermal analysis and new insights to support decision making in retrofit and relaxation of heat exchanger networks
2011
International audience; Pinch analysis offers a rational framework for identifying energy saving targets and designing efficient heat recovery networks, especially in process industry. Several scientists have contributed to improve and automate the original pinch method over the last decades, increasing its capability to deal with a number of specific issues; the expertise of the analyst, however, remains determinant in achieving optimal results. In this paper a procedure for retrofit of existing networks is proposed, based on an integrate use of several techniques (either existing or innovative). The diagnosis of the existing network and of a "Minimum Energy Requirement" configuration emer…
Mechatronic Concept for Airflow Tests Laboratory Equipment
2015
The paper presents application of the mechatronic concept for laboratory test to support a research activity. Laboratory test is taken into account as set of processes for which some number of environmental parameters must be controlled. This paper describes the laboratory stand for investigations of airflow phenomena, where modern data acquisition system is applied to control pressure, temperature and velocity of the air stream. To acquire and process a large number of data, the idea of virtual instruments is introduced to control system. Modern, high-level graphical language was used and the author’s program was developed. The presented solution of the laboratory stand allows increasing t…
Local capacity H<inf>∞</inf> control for production networks of autonomous work systems with time-varying delays
2009
This paper considers the problem of local capacity H ∞ control for a class of production networks of autonomous work systems with time-varying delays in the capacity changes. The system under consideration is modelled in a discrete-time singular form. Attention is focused on the design of a controller gain for the local capacity adjustments which maintains the work in progress (WIP) in each work system in the vicinity of planned levels and guarantees the asymptotic stability of the system and reduces the effect of the disturbance input on the controlled output to a prescribed level. In terms of a matrix inequality, a sufficient condition for the solvability of this problem is presented usin…
Tool replacement with adaptive control in a non-stationary non-periodic stochastic process
1991
Abstract The problem of optimum tool replacement is studied in the case in which tool performance is characterized by progressive decay over time following stochastic laws. A control system is assumed which detects, continuously or at fixed intervals, the service state of the tool. Assuming that the service state of the tool affects the marginal cost of production, the latter is used in order to minimize the unit production cost for an unlimited production horizon. The replacement policy proposed is able to update itself in process by means of an iterative procedure which converges to a conditioned optimum. The effectiveness of such a policy is demonstrated analytically, and illustrative ex…
A double genetic algorithm for the MRCPSP/max
2011
This paper presents a heuristic solution procedure for a very general resource-constrained project scheduling problem. Here, multiple execution modes are available for the individual activities of the project. In addition, minimum as well as maximum time lags between different activities may be given. The objective is to determine a mode and a start time for each activity such that the temporal and resource constraints are met and the project duration is minimised. Project scheduling problems of this type occur e.g. in process industries. The heuristic is a two-phased genetic algorithm with different representation, fitness, crossover operator, etc., in each of them. One of the contribution…
Stability Analysis of Large Scale Networks of Autonomous Work Systems with Delays
2011
This paper considers the problem of stability analysis for a class of production networks of autonomous work systems with delays in the capacity changes. The system under consideration does not share information between work systems and the work systems adjust capacity with the objective of maintaining a desired amount of local work in progress (WIP). Attention is focused to derive explicit sufficient delay-dependent stability conditions for the network using properties of matrix norm. Finally, numerical results are provided to demonstrate the proposed approach.