"MADE IN ITALY" AND "MADE IN CHINA". EMPIRICAL ANALYSIS AND INDUSTRIAL POLICY IMPLICATIONS

quality, sectoral specialisation, international trade, price differentials

A General Mathematical Formulation for the Determination of Differential Leakage Factors in Electrical Machines with Symmetrical and Asymmetrical Full or Dead-Coil Multiphase Windings

This paper presents a simple and general mathematical formulation for the determination of the differential leakage factor for both symmetrical and asymmetrical full and dead-coil windings of electrical machines. The method can be applied to all multiphase windings and considers Görges polygons in conjunction with masses geometry in order to find an easy and affordable way to compute the differential leakage factor, avoiding the adoption of traditional methods that refer to the Ossanna's infinite series, which has to be obviously truncated under the bound of a predetermined accuracy. Moreover, the method described in this paper allows the easy determination of both the minimum and maximum values of the differential leakage factor, as well as its average value and the time trend. The proposed method, which does not require infinite series, is validated by means of several examples in order to practically demonstrate the effectiveness and the easiness of application of this procedure

Does industry resilience matter for postshock industrial policy? A focus on tourism-related industries

Selective industrial policies have been increasingly used by governments to achieve desired normative goals. However, they have been revealed to be complex and vulnerable interventions, demanding robust tools able to justify choices and mitigate potential ‘government failures’. In light of the emerging challenges and potential disruptions that might threaten our economies and societies, we contend that postshock industry resilience can be a valuable analytical framework to understand how different sectors react to unforeseen shocks. Accordingly, we present a methodology that measures postshock industry resilience and apply it to the Italian case in the aftermath of the 2008 shock. Particular attention is devoted to tourism-related industries. Main findings show that the industries reacted heterogeneously to the 2008 shock. For tourism-related industries, the results suggest following an ad hoc approach to the analysis of each tourism-focused industry to avoid generalizations that might lead to incorrect policy interpretations

Rotor bar pre-fault detection in the squirrel cage induction motors

The paper deals with a diagnosis technique to detect and monitor incipient faults in the rotor bars of squirrel gage induction motors. The failure mode analysis is performed monitoring the motor axial vibrations. To accomplish the task, the authors present a mathematical model that allows relating the occurrence and the severity of the faults to the presence and the magnitude of some frequency components of the axial vibration spectrum. To validate the proposed approach, the results obtained by applying the mathematical model are compared with the ones obtained by experimental tests done on both healthy and faulty motors

A Novel, Simple and Flexible Fault-Tolerant Control Algorithm for Multiphase Electrical Machine Operation Under Open Circuit Faults

This paper presents a novel and simple procedure for the determination of a Fault-Tolerant Algorithm (namely FTA) for the adequate working operation of an electric machine equipped with a general m-phase winding under possible open circuits occurring in some of its phases. The FTA is firstly theoretically derived from the analysis of the magnetic field distribution in polyphase systems, then simulated through finite-element analysis and finally implemented via software for real-time validation. The effectiveness of the proposed procedure is confirmed through experimental tests on a laboratory setup. Key contributions include the flexibility of the algorithm, which can be applied to any m-phase electric machine with various winding configurations. Both the obtained FEA and experimental results demonstrate that the proposed control algorithm can be easily used and applied in electric drives supplied by m-phase motors under fault conditions without significantly affecting the magnetic performance of the whole system and ensuring the continuity of operation even in the presence of faults

Voltage source inverters: an easy approach for fast fault detection

Peer Reviewe

Sensorless variable speed single-phase induction motor drive system based on direct rotor flux orientation

The single-phase induction motor (SPIM) is one of the electrical machines more used in the World, and can be found in several fractional and sub-fractional horsepower applications in houses, offices, shoppings, farms, and industries. The introduction of more sophisticated applications has required the use of variable speed drives for SPIM, where the adoption of sensorless techniques is the more reasonable option for speed control due to the low cost of this electrical machine. A proposal for sensorless variable speed SPIM drive based on direct rotor field orientation techniques is presented in this paper. None transformation is used in order to eliminate the asymmetry of the stator windings of the SPIM. The rotor speed is estimated from an flux observer, which is based on two independent linear feedback control systems. The speed and flux estimatives are used in two control loop based on PID regulators, which determine the voltages to be applied to the SPIM windings by a three-legs VSI inverter. Using computer simulations, two situations are considered in order to demonstrate the satisfactory performance of the proposed sensorless speed control for SPIM drives: variations on rotor speed reference and the application of mechanical load

Cogging torque comparison of Interior Permanent Magnet Synchronous Generators with different stator windings

This paper presents the comparison between the cogging torques produced by four IPMSGs (Interior Permanent Magnet Synchronous Generators) with different stator winding configurations. More in detail, an IPMSG model, which is derived from a commercial geometry, is analyzed through means of a FEM (Finite Element Method) approach. Then, three more structures are determined and analyzed by adequately changing the number of stator slots of the basic IPMSG stator structure and by maintaining the same rotor configuration. From the obtained simulation results, the cogging torque components for each structure are determined and compared. From this comparison, it can be stated that the use of dissymmetric windings does not affect significantly the generated cogging torque

Simulating excited states in metal organic frameworks: from light-absorption to photochemical CO₂ reduction

Metal-organic frameworks (MOFs) have a wide range of optoelectronic and photochemical applications, many of which are directly dependent on their excited states. Computational modelling of excited state processes could aid the rational design of effective catalysts, but simulating MOFs in their excited state is challenging. This is due to the inherent molecule/crystal duality of MOFs, their large and diverse unit cells, and the unfavourable scalability of quantum chemical methods. However, periodic and cluster models have been developed and applied to characterise the excited states of MOFs and their properties, such as charge transfer, luminescence, and photocatalytic mechanisms. Additionally, embedding techniques provide a means of explicitly incorporating the crystal environment in such models. Although many high-quality reviews have assessed computational modelling in MOFs, most have focused on the study of ground-state electronic properties. In this perspective, we focus on the computational methods available to describe the excited states of MOFs from the molecular, periodic, and embedding perspectives. To illustrate the performance of cluster and periodic models, we compare the results obtained using both approaches at different levels of theory for an exemplary MOF. We also analyse examples from modelling relevant photochemical and photophysical including charge transfer, exciton effects, chemosensing, host-guest mechanisms, thermally activated delayed fluorescence and room temperature phosphorescence. Additionally, we show how such methods can be applied to predict MOF-based photocatalytic CO2 reduction to value-added chemicals. We emphasise the advantages and limitations of current methodologies, as well as the potential for utilising databases and machine learning models in this context