Identifying and evaluating parallel design activities using the design structure matrix

This paper describes an approach based upon the Design Structure Matrix (DSM) for identifying, evaluating and optimising one aspect of CE: activity parallelism. Concurrent Engineering (CE) has placed emphasis on the management of the product development process and one of its major benefits is the reduction in lead-time and product cost [1]. One approach that CE promotes for the reduction of lead-time is the simultaneous enactment of activities otherwise known as Simultaneous Engineering. Whilst activity parallelism may contribute to the reduction in lead-time and product cost, the effect of iteration is also recognised as a contributing factor on lead-time, and hence was also combined within the investigation. The paper describes how parallel activities may be identified within the DSM, before detailing how a process may be evaluated with respect to parallelism and iteration using the DSM. An optimisation algorithm is then utilised to establish a near-optimal sequence for the activities with respect to parallelism and iteration. DSM-based processes from previously published research are used to describe the development of the approach

Kinds and Essences: Rescuing the New Biological Essentialism

Màster en Filosofia Analítica (APhil), Facultat Filosofía, Universitat de Barcelona, Curs: 2021-2022, Director/Tutor: Esa Díaz-LeónAfter the rise of Darwin’s theory of evolution it seemed that the much-feared ghost of traditional essentialism had disappeared from biology. However, developments of the last century in analytic metaphysics (Kripke, Putnam, Wiggins) appear to have resurrected the Aristotelian monster in various forms. The aim of this paper is to investigate the revival of the essentialist doctrine as applied to biological species, namely the thesis that organisms belong to a particular natural kind in virtue of possessing certain essential properties, and examine to what extent these new biological essentialisms are sustainable. For this purpose, I intend to analyze these proposals in both their forms, relational essentialism (Okasha, LaPorte) and intrinsic essentialism (Devitt), and confront them with their main anti-essentialist criticisms. The answer, I advance, is that natural kind essentialism as applied to biological taxa is, not only tenable, but theoretically adequate. Yet not in its typical variants. I contend that understood as HPC kinds (Boyd, Wilson), organisms possess clusters of co-occurring properties that are caused by various mechanisms which in turn determine the shared similarities that define membership to species. Such an approach encompasses both the intrinsic and relational mechanisms that make species members be what they are. However, this theory faces criticisms regarding circularity and the problem of polymorphism (Ereshefsky & Matthen). I suggest that reinterpreting the HPC theory as informationally-connected property clusters (Martínez) solves the objection posing an improved version of the HPC theory and providing what I believe is a theoretically adequate and explanatorily robust version of biological essentialism

Implementing Management Systems and Demand Driven MRP concepts: A Project Based Learning experience in Industrial Organization Engineering

[EN] This research work presents an experience of the Faculty of Engineering of Mondragon Unibertsitatea using Project Based Learning (PBL) with the students of 4th semester of Bachelor's Degree in Industrial Organization Engineering (IOE). The PBL delved into the concepts developed in the subjects of Management Systems and Production Logistics. The project was contextualized in a company that produced parts for the automotive sector. Teams of students implemented a management system that enabled the efficient management of materials and the production process using tools such as Demand Driven MRP (DDRMP). As a result, they had to solve the proposed problem, develop a simulation and choose the proposal that best met the needs of the company. In order to assess PBL performance a survey was carried out. The results confirmed that the experience was positive since the achieved knowledge provided a meaningful learning experience for the students, while facilitating the development of both technical and transversal competences. http://ocs.editorial.upv.es/index.php/HEAD/HEAD18Kortabarria, A.; Elizburu, A. (2018). Implementing Management Systems and Demand Driven MRP concepts: A Project Based Learning experience in Industrial Organization Engineering. Editorial Universitat Politècnica de València. 543-550. https://doi.org/10.4995/HEAD18.2018.8033OCS54355

New Modulation Technique to Mitigate Common Mode Voltage Effects in Star-Connected Five-Phase AC Drives

Star-connected multiphase AC drives are being considered for electromovility applications such as electromechanical actuators (EMA), where high power density and fault tolerance is demanded. As for three-phase systems, common-mode voltage (CMV) is an issue for multiphase drives. CMV leads to shaft voltages between rotor and stator windings, generating bearing currents which accelerate bearing degradation and produce high electromagnetic interferences (EMI). CMV effects can be mitigated by using appropriate modulation techniques. Thus, this work proposes a new Hybrid PWM algorithm that effectively reduces CMV in five-phase AC electric drives, improving their reliability. All the mathematical background required to understand the proposal, i.e., vector transformations, vector sequences and calculation of analytical expressions for duty cycle determination are detailed. Additionally, practical details that simplify the implementation of the proposal in an FPGA are also included. This technique, HAZSL5M5-PWM, extends the linear range of the AZSL5M5-PWM modulation, providing a full linear range. Simulation results obtained in an accurate multiphase EMA model are provided, showing the validity of the proposed modulation approach.This work has been supported in part by the Government of the Basque Country within the fund for research groups of the Basque University system IT978-16 and in part by the Government of the Basque Country within the research program ELKARTEK as the project ENSOL (KK-2018/00040)

Multi revolution finite element model to predict machining induced residual stresses in Inconel 718

Inconel 718 is commonly used in structural critical components of aircraft engines due to its mechanical thermal properties at high temperatures, which makes it to be considered as a difficult to machine material. In these critical parts, such as disk turbines, surface integrity should be assured in order to ensure the expected fatigue life. In order to determine the influence of feed and depth of cut in residual stresses a finite element facing model has been developed. This model takes into account the complex thermo mechanical phenomena that take place during chip formation process as well as the effect of cyclic loading phenomena due to the successive revolutions. Firstly, full stress, strain and temperature fields are obtained with a Deform 3D v10.2 nose turning model. Those fields are introduced in a multi revolution Abaqus/Standard v6.12 machining model. Finally the residual stresses of the model are extracted as an approach of Hole Drilling measurement technique. The results are in good agreement with empirical measurements