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Powertrain ibride da competizione: sicurezza, controllo e automatizzazione
Full text linkL'applicazione di nuove tecnologie, legate alla ricerca di una riduzione dei problemi riguardo l'impatto ambientale, è un tema ricorrente in diversi ambiti tecnici. Nel campo dei veicoli gli studi volti all'aumento dell'efficienza dei sistemi propulsivi rappresentano uno dei settori di maggiore fermento. La costante crescita del parco circolante mondiale rende sempre più necessaria la ricerca di una soluzione in grado di diminuire l'impatto ambientale delle vetture e, conseguentemente, i consumi di derivati del petrolio, le cui riserve vanno via via esaurendosi. Tra le tecnologie più promettenti vi sono sicuramente i veicoli elettrici e ibridi. La diffusione di massa dei primi è legata a problemi economici e infrastrutturali, non sarà infatti possibile costruire veicoli elettrici competitivi finché il prezzo delle batterie non scenderà almeno fino a 500. Una volta raggiunta questa soglia, per la quale gli studi di importanti società di consulenza, quali il Boston Consulting Group e Rolland Berger, danno orizzonti temporali di circa 5-7 anni, sarà poi necessario costruire infrastrutture in grado di garantire la ricarica rapida dei pacchi batteria ad alta capacità. La tecnologia dei sistemi ibridi basati su batterie al litio, rappresenta invece una soluzione attuale, che si avvicina sempre più alla maturità tecnica. I motori elettrici possono raggiungere efficienze nell'ordine del 90% nell'intero range di utilizzo, possono recuperare energia attraverso la funzione di frenata rigenerativa ed essere utilizzati per implementare strategie di power splitting, utili a limitare il consumo di carburante dei motori a combustione interna. Il settore delle competizioni, per tradizione, ha il ruolo di porsi come avanguardia del settore automobilistico nell'utilizzo delle nuove tecnologie e questa tesi rappresenta la sintesi di un percorso di ricerca e sperimentazione nel campo delle motorizzazioni ibride applicate alle competizioni automobilistiche. Come noto, il settore automotive è contraddistinto da una forte multidisciplinarità e questo aspetto risulta enfatizzato nelle applicazioni trattate all'interno di questo documento. Installare una powertrain ibrida a bordo di una vettura da competizione comporta, infatti, competenze nel campo dell'elettronica e del progetto di controlli, competenze di dinamica del veicolo, di progettazione meccanica e di costruzione dei veicoli terrestri. L'applicazione ai prototipi da competizione accentua ulteriormente la necessità di integrare le competenze del gruppo progettuale, che deve forzatamente fare efficienza per raggiungere risultati rilevanti con budget, tempistiche e organico spesso sottodimensionati. La trasversalità degli argomenti trattati rappresenta uno degli aspetti fondanti della meccatronica e, per questo motivo, lo studio di powertrain ibride è stato scelto come argomento di ricerca per lo svolgimento di tre percorsi di dottorato e per la stesura delle relative tesi. I tre documenti trattano tre diversi aspetti dello studio e della progettazione dei sistemi ibridi, il primo è dedicato al dimensionamento meccanico ed elettrico dei sistemi con particolare attenzione al progetto di pacchi batterie ad alte prestazioni, il secondo si concentra sulla modellistica necessaria al progetto di un sistema ibrido, sul lavoro di calibrazione e validazione dei modelli e sulle attività di sperimentazione e sviluppo degli stessi. Questo documento è invece dedicato all'elettronica necessaria alla gestione del sistema e al progetto di un controllo che ne automatizzi il funzionamento e ne garantisca la sicurezza. Al fine di contestualizzare e introdurre i progetti trattati, sono stati redatti dei capitoli comuni ai tre documenti che riassumono i risultati congiunti del lavoro dei tre autori attraverso la descrizione dei sistemi realizzati e dei risultati raggiunti. Per necessità di sintesi si è, infatti, deciso di focalizzare l'attenzione su due applicazioni pratiche, una piccola monoposto per competizioni studentesche di Formula Hybrid, la Sc08h, e una vettura gran Turismo su base Ferrari progettata per concorrere alla 24 ore del Nurburgring, la P4/5 Competizione. Il campo di applicazione descritto pone delle limitazioni alla divulgazione di alcune informazioni come, ad esempio, le caratteristiche di alcuni componenti sperimentali ma, allo stesso tempo, consente l'opportunità di vedere realizzato il risultato del lavoro di ricerca ed il privilegio di validare e verificare le ipotesi e le assunzioni formulate in fase progettuale. Il profondo connotato applicativo del lavoro di ricerca rende molto semplice evidenziarne gli obiettivi: - Indagare e consolidare le migliori pratiche relative alla progettazione di veicoli ibridi; - Realizzazione e validazione della modellistica atta a guidare il dimensionamento di powertrain ibride; - Valutare le effettive prestazioni delle tecnologie oggi disponibili sul mercato. Il contributo scientifico di questo lavoro è trasversale a tutti gli obiettivi appena elencati e può essere riassunto nell'intenzione di creare cultura ingegneristica nel campo della progettazione di sistemi ibridi. Come avviene per molte tecnologie giovani, i riferimenti bibliografici relativi alla progettazione pratica di sistemi propulsivi che accoppino motori a combustione interna e motori elettrici sono, a oggi, molto carenti. I tre lavori di tesi presentati vogliono cercare di sopperire alla carenza appena citata attraverso la descrizione approfondita del processo progettuale seguito per realizzare i due sistemi ibridi. La descrizione approfondita della modellistica utilizzata, delle soluzioni tecniche adottate e il processo di validazione e sviluppo possono costituire un punto di partenza interessante per chi debba approcciarsi allo sviluppo di un sistema ibrido. Al fine di rendere effettivamente utilizzabile e migliorabile la strategia progettuale adottata, è stata riservata molta attenzione a particolari pratico-realizzativi che, anche se non strettamente definibili scientificamente rilevanti, rappresentano un importante bagaglio di competenze necessarie all'utilizzo delle tecnologie ibride. Tralasciando i contenuti del presente capitolo, è possibile elencare brevemente gli argomenti trattati all'interno dei capitoli successivi al fine di rendere chiara e comprensibile la struttura del documento. Il capitolo due descrive le tecnologie utilizzate nel settore delle propulsioni ibride e descrive brevemente le applicazioni nel settore delle competizioni automobilistiche. I capitoli tre e quattro sono dedicati al progetto Sc08h del quale viene dato un approfondito resoconto per lo più orientato alla sicurezza e al controllo. I capitoli cinque e sei parlano del progetto P4/5 Competizione, ne descrivono le caratteristiche e i risultati. È possibile evidenziare una sostanziale continuità tra i capitoli tre, quattro, cinque e sei all'interno dei quali vengono trattati gli stessi argomenti su due progetti diversi e che testimoniano la crescita di competenze nell'arco dei tre anni dedicati alla ricerca nel campo delle trazioni ibrid
A review of quantitative analysis techniques for construction project risk management
No full textConstruction industry is at the forefront of risk: it involves situations where uncertainty is a norm. Based on the volatility built into the very nature of this industry, risk management has been an integral part of construction management. The variety of risks faced in construction industry is enormous and there are correspondingly various techniques available to respond to the critical situations. Quantitative analysis techniques, based on their sophisticated mathematical, statistical and scientific background, promise a detailed and thorough quantification and measurement of risk, which is very important for designing the response. A construction project manager may not be able to plan the response effectively without an exhaustive knowledge of the volume of risk. This paper presents a review of various quantitative risk analysis techniques. It tries to build an overall understanding of various existing quantitative techniques for construction project risk analysis. It initially uses results of a survey to find out the trends of construction industry, globally, in terms of utilization of quantitative risk analysis and relevant techniques. Further, it looks into the details of the techniques from the published material. Finally, it reports some critical findings from the survey and literature review, and their logical and scientific deduction by stressing both, researchers and practitioners, towards the need for simplifying the existing quantitative techniques. It also tries to identify some research gaps. In conclusion, it proposes areas of future research in quantitative techniques for construction project risk management by improving existing techniques or making new one
Construction Risk Taxonomy: An International Convergence of Academic and Industry Perspectives
Full text linkRisk management is a topic heavily researched and important for industry professionals. Both academic and industry perspectives are critical to advancing this field, especially in risk identification and taxonomy. A unique comparison and convergence of these perspectives is developed in order to understand the most relevant risks for projects and to ensure they are addressed in the risk management process. This comparison is created via a content analysis of the relevant literature and a survey to industry professionals. The differences and similarities among risks are analyzed, revealing that both perspectives emphasize financial/economic risks. The literature tends to focus on political; acts of God classified risks, whereas the industry places emphasis on regulatory risks. An elaboration of variations is performed aiming to improve the literature-based taxonomy taking into account the industry perspective to ensure its risk management process responds to these risks and provides a clearer focus towards future research
Dynamic Management of Risk Contingency in Complex Design-Build Projects
Full text linkContingency budgets are commonly used by managers to respond to uncertainty and control the project within the original cost and schedule targets. However, a variety of project participants with conflicting interests creates tensions when it comes to managing the risk contingency escrow account during the project development, and divergences often arise over the need for either retaining the unspent contingencies (for future risk and improved facility) or releasing it as a profit. With the purpose of studying the dynamics and main influences involved in the risk contingency management process of a design-build (DB) project, a system dynamics (SD) contingency management model is proposed to simulate the decision-making scenarios, under different project conditions and behavioral pressures of senior managers and owners. The model suggests that an aggressive proactive risk management practice might be an effective policy for managing the contingency budget in a complex engineering, procurement, and construction (EPC) projec
Risk Analysis in Construction Projects: A Practical Selection Methodology
Full text linkProject Risk Management (PRM) is gaining attention from researchers and practitioners in the form of sophisticated tools and techniques to help construction managers perform risk management. However, the large variety of techniques has made selecting an appropriate solution a complex and risky task in itself. Accordingly, this study proposes a practical framework methodology to assist construction project managers and practitioners in choosing a suitable risk analysis technique based on select project drivers. Additionally, the methodology transforms the traditional triple constraints by broadening the focus from the project to a combination of the project and PM organization. Scale harmonization is achieved by dividing the selected project drivers and risk analysis categories into four levels. The applicability and efficiency of the methodology is demonstrated in two actual construction projects by creating a radar chart and performing their ex-post risk analysis with the help of the developed technique. The study contributes to the existing body of knowledge on PRM as a practical tool that helps project managers select suitable risk analysis techniques under given project characteristic
Risk-Adjusted Contingency Management in Construction Projects
Full text linkSuccessful project management (PM) aims at achieving the triple-constraint (time, cost and quality), respecting the elasticity between the three main drivers. To facilitate this, PM activities are supported by project risk management (PRM) in foresight and earned value management (EVM) in hindsight. Both PRM and EVM, being industry standards, facilitate to plan, and afterwards monitor and control the project cost. However, the two fields do not necessarily interact with each other which, in turn, hinders critical managerial decision making of releasing contingency reserves if demanded by the client since the money can be used as capital for other projects. Also, when inquired at any given point in time (corresponding to partial project completion), the project managers (PMs) find it tricky and challenging to confidently declare the adequacy of existing reserves till the project completion This provides research impetus for potential EVM-PRM integration and managing the contingency adjusted due to risk in the project. There is hardly any literature on this integration, resulting in lack of any viable framework to facilitate critical decision making. With objective to formulate a framework - coupled with necessary tools and techniques - this paper proposes the incorporation of EVM and PRM which aims at not only expanding the body of knowledge in the field of ‘project control'1 but also assist the PMs in securely and successfully steering the project to close out. The research is still in progress and no conclusive details are furnished as ye
A Survey on Usage and Diffusion of Project Risk Management Techniques and Software Tools in the Construction Industry
Full text linkThe area of Project Risk Management (PRM) has been extensively researched, and the utilization of various tools and techniques for managing risk in several industries has been sufficiently reported. Formal and systematic PRM practices have been made available for the construction industry. Based on such body of knowledge, this paper tries to find out the global picture of PRM practices and approaches with the help of a survey to look into the usage of PRM techniques and diffusion of software tools, their level of maturity, and their usefulness in the construction sector. Results show that, despite existing techniques and tools, their usage is limited: software tools are used only by a minority of respondents and their cost is one of the largest hurdles in adoption. Finally, the paper provides some important guidelines for future research regarding quantitative risk analysis techniques and suggestions for PRM software tools development and improvement
Project Risk Management for Sustainable Building Repair & Maintenance in Developing Countries
Full text linkBuilding repair & maintenance (R&M) are inevitable: building omponents deteriorate with time due to aging, constant use - causing wear and tear, possible design and construction defects, and the consequences of environmental agents and vulnerabilities. The situation worsens in developing countries where large number of externalities dictates the R&M decisions: lack of budget, enforcing regulation and building standards to name a few. These and other inherent uncertainties grow to be considerable risks of peculiar nature, which demand an active and customized management. The need to manage risk of R&M projects is paramount: starting from affective identification to seamless analysis, and suitable response planning to meticulous monitoring and control, a custom-structured project risk management (PRM) framework - a combination of specialized tools and techniques - will greatly help by considering how risky these undertakings are, dealing with apparent threats and converting them into opportunities. To this end, this paper, after reviewing the R&M state of affairs in developing countries, proposes a functional PRM framework to manage R&M ris
A Framework Methodology for Selection of Risk Analysis Techniques in Construction Projects
No full textProject Risk Management has been gaining acceptance amongst the practitioners due to an untiring stress on its importance, and the availability of a number of risk analysis techniques for facilitating this task in construction project management. In this arena, the selection of a suitable risk analysis technique is critical to the entire project risk management process and thus critical to the success of a construction project. However, the availability of an appropriate selection methodology, which may help the project managers choose a suitable methodology for their projects, seems missing. In this paper a selection framework methodology is presented, which looks at the realization of a practical tool that may help project managers and construction practitioners in choosing a suitable risk analysis technique that satisfies select project drivers. Also, the presented work extends the traditional time, cost and quality drivers of a project by enhancing the focus to the level of complexity and maturity of the organization. The project drivers are further classified into four scales each, to assist in formulating a well-structured chart. The dimension of project risk analysis technique is classified into qualitative, semi-quantitative, quantitative, and simulation scales, rendering a balanced diagram. Plotting the project drivers on the chart result in acquisition of the category of risk analysis technique, which is appropriate under given variables. The paper further proposes individual classification of existing techniques into the four categories of project risk analysis dimension, which may help practitioners to obtain a specific technique for their construction project by conveniently putting in the variables into the proposed chart. Applicability of the framework methodology is finally presented followed by conclusions and future research direction
Critical review of nano and micro-level building circularity indicators and frameworks
No full textThe circular economy (CE) paradigm can eradicate the problems caused by the traditional linear economic approach adopted by the building industry. But the efforts to implement CE in the building and construction industry are fragmented and lack consensus. If improved, the ability to measure and report on progress can help in effectively transiting to CE. In this regard, wide-ranging building circularity indicators (C-indicators) have been proposed. However, the extant literature highlights that the comprehensive research on existing CE assessment tools in the building industry is still lacking, while policymakers (e.g., European Commission) and standards (e.g., ISO) have emphasized the need for a universally recognized circularity framework for buildings. To help this cause, this review inventories and critically analyzes 35 existing tools through an extended systematic literature review of 51 carefully selected documents from both academic and grey literature. It is found that there is a sharp increase in publications in recent years, with Europe leading the way. Along with the academic community, government agencies and consulting companies have also developed several C-indicators. The content analysis suggests that most indicators are quantitative and can vary in terms of the scale of application, the adopted CE scope and definition, and the underlying key performance indicators (KPIs). The descriptive analysis reveals that most indicators are in the developing stage and substantially stress recycling and reuse, overlooking some important aspects like energy, emission, and water. Innovative technical solutions like the design for adaptability and disassembly are excessively used to measure the circular potential of structures. The existing sustainability and circularity tools are seen as a good starting point for developing new frameworks. This extensive review and critical analysis provide a synthesis and explanation of the developing research theme of building C-indicators and highlight the remaining key challenges. The findings can drive the standardization of a universally accepted framework
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