This work has been developed among the researches of a PhD thesis in Civil and Environmental engineering and architecture of the University of Udine in cooperation with the GECO Laboratory of the University of Florenc...
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This work has been developed among the researches of a PhD thesis in Civil and Environmental engineering and architecture of the University of Udine in cooperation with the GECO Laboratory of the University of Florence. It focuses on the interaction between Geomatics and Structural Analysis, both applied to cultural heritage, and expressly to artefacts and structures in stone materials, like the case study of this paper, the marble statue called "San Giovannino Martelli" (Saint John the Baptist) conserved in Florence. At the beginning, some interesting examples of surveying and structural analyses on statues are reported, in order to remind the complementary tasks and requirements of geomatics and structural analysis. Current laser scanning systems can accurately survey the geometry of a statue or any cultural heritage artefact, essential to understand their structural behaviour and resilience capability. Afterwards, following the few Italian regulations in this field, the possible risks of museum goods are described: Topics of this part are more familiar for structural engineers as object classification, seismic reactions, damage mechanisms, possible movements (adherent, slipping and oscillation), dynamic domains, anyway necessary steps to evaluate the risk and so to define eventual interventions. The artistic description of the statue, its debated attribution to Donatello or/and to Desiderio da Settignano and its history is later recalled, remembering that the surveying has been done for the idea to 3D print a replica and to place it in the original place. Having used a close range laser scanner, the obtained 3D model has an impressive geometrical Level of Detail (LoD), whose geometric features are explained in the paper, underlying that such extremely detailed mesh is directly given as output from the laser scanner software. The model simplifications by four decimation are therefore explained and also changes to geometry, like shifts on centre of the mass or bary
This paper demonstrates laterally vibrating lithium niobate (LN) microelectromechanical (MEMS) resonators operating at 500 MHz with an electromechanical coupling coefficient (k t 2 ) around 30% - the highest ever atta...
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ISBN:
(纸本)9781509050796
This paper demonstrates laterally vibrating lithium niobate (LN) microelectromechanical (MEMS) resonators operating at 500 MHz with an electromechanical coupling coefficient (k t 2 ) around 30% - the highest ever attained for this class of resonators. This accomplishment is made possible by the use of direct bonding of bulk X-cut LN wafers to high resistivity silicon and a resonator electrode layout that permits harnessing the full capabilities of the film.
The improvement of energy efficiency and the use of environmentally friendly working fluids are key elements of current European policies. Supermarkets are intensive energy consumers and approximately the 40% of their...
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The improvement of energy efficiency and the use of environmentally friendly working fluids are key elements of current European policies. Supermarkets are intensive energy consumers and approximately the 40% of their annual energy consumption is for refrigeration. Direct emissions of greenhouse gases associated with the use of high Global Warming Potential (GWP) refrigerants, and the indirect impact on the environment related to high electrical energy consumption, make shopping malls not sustainable buildings. This paper analyses the energy saving potential of integrated supermarket air conditioning and refrigeration systems using a Water Loop Heat Pump system (WLHP). A basic CO 2 booster commercial refrigeration system, applied to cold rooms and display cabinets, is considered. Heat recovery from the refrigeration circuit is performed in the heating season, while in the cooling season a dry cooler on the water loop allows heat rejection to outdoors. The building and all systems are modelled in the Trnsys environment taking into account the hourly weather data, the simulated daily profiles of the cooling and heating load demand and the request from refrigerated food storage equipment. Such a model allows a thorough understanding of the potential for energy savings with heat recovery solutions.
The problem of personnel and interventions scheduling faced by a container ship maintenance service provider (MSPC), commonly the manufacturer of a main ship subsystem such as engines, is analysed. Clients can make a ...
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The problem of personnel and interventions scheduling faced by a container ship maintenance service provider (MSPC), commonly the manufacturer of a main ship subsystem such as engines, is analysed. Clients can make a request for a maintenance service of a containership at a given harbour with a given number of days in advance to the desired date, as established in the service contract. The MSPC is allowed to delay the intervention to any future stop of the route within a specified time window depending on its urgency, as set in the contract. The MSPC technicians can be divided into different categories of skills and further distinguished as belonging to the MSPC main company, to the MSP network of subsidiaries, or hired on demand, with different availability constraints, personnel costs, and transport costs in relation to harbour proximity. Delays on planned arrival dates to harbours as well as changes in the duration of stay are common due to bad meteorological conditions, congestions at harbours, or other issues arisen during sailing or previous stops, so a rolling planning horizon should be adopted to face such a dynamic environment. A Constraint Programming optimisation model hybridized with Large Neighborhood Search is proposed in order to address the problem and its performance compared to actual plans from a world-wide known MSPC. The model has been developed to perform also as a decision making tool; a factorial design of experiment is adopted in order to analyse the impact of a change in some contractual features, such as the minimum time allowed to clients for requiring a service, or the maximum delay allowed to the MSPC to satisfy a service request. How granting clients more flexibility while preserving efficacy and efficiency of the service can so be investigated.
This paper presents a novel technique to perform the topological pre-processing needed in formulations based on an electric vector potential and a magnetic scalar potential when the eddy current problem being solved i...
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ISBN:
(纸本)9781509010332
This paper presents a novel technique to perform the topological pre-processing needed in formulations based on an electric vector potential and a magnetic scalar potential when the eddy current problem being solved is subject to periodic boundary conditions (PBC). In this case, in fact, all the techniques to produce the generators for the first cohomology group introduced in literature cannot be used. The novel technique is very fast and it is used to model cables for power delivery.
In the sheet metal industry, single machines or more complex production systems are integrated with a software needed to control them. While it is clear both for the company and the client that the machine is a produc...
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In the sheet metal industry, single machines or more complex production systems are integrated with a software needed to control them. While it is clear both for the company and the client that the machine is a product offered with the related services, the software deserves more attention. In the company where our team has been involved in an action research program, the software is conceived as a product with its related services, but this concept has not been properly transmitted to clients, who don’t recognize it and pretend software services for free. In this industry, machinery is linked to its software and both are enhanced by the related services, so the final product-service bundle should be made by four components. In order to better clarify this concept and illustrate the solutions our research team has identified to promote a complete PSS offer, the four-leg chair metaphor is proposed. The proper value of the whole PSS offer can be transmitted by an effective communication process, supporting sales people with instruments such as predefined packets for software services. Organisational changes should be adopted such as job enlargement for software technicians and cross-training with salespeople. By the former, software technicians, who are frontline employees in direct contact with customers during the training phase, can be transformed into internal entrepreneurs by proper incentives. Since they lack marketing education and sometimes trust of salespeople, cross-training is proposed as an effective way to keep in touch software technicians with salespeople with mutual learning.
In the control of Interior Permanent Magnet Synchronous Machines (IPMSMs), Maximum Torque Per Ampere (MTPA) based on motor parameters is a common approach to achieve high efficiency and torque density. Parametric unce...
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ISBN:
(纸本)9781509007387
In the control of Interior Permanent Magnet Synchronous Machines (IPMSMs), Maximum Torque Per Ampere (MTPA) based on motor parameters is a common approach to achieve high efficiency and torque density. Parametric uncertainty (e.g. due to identification errors, magnetic saturation or temperature variation) results in undesired deviation from the optimal operating trajectory. To solve this problem, MTPA tracking methods have been proposed, which exploit signal injection to search the minimum current point for a certain load torque, in a closed-loop fashion. For one of these methods, [13], stability of the non-linear dynamics was analyzed, and an upper bound for the convergence time was found, but no explicit method was proposed for the design of the tracking regulator. In this paper this last topic is addressed. By introducing some approximations, the linearized system is calculated and a loop transfer function obtained, which is invariant with the operating point. Thus, by means of a very simple design rule (i.e. suitable for auto-tuning), the MTPA tracking regulator gains can be designed in order to obtain the desired bandwidth. The method has been studied analytically and in simulation, also considering the influence of noise and parametric uncertainties. Finally the technique has been implemented on the hardware of a commercial industrial drive, proving the effectiveness of the proposal.
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