Search results for "Liability"
showing 10 items of 1754 documents
Improving Maintenance Activities of Machine Tools
2013
The paper follows the current trends in the field of maintenance, proposing approaches that fit in the concept of Total Productive Maintenance (TPM). First it is presented a new proposal for tracking in-service machine tools. This is based on the identification of three operating states: good running condition, state of repair and stationary state. During the stationary state there are differentiated two distinct types of stops: natural stays and unproductive stays (those who often produce considerable losses). Based on the information contained in the records made for tracking the operation of machine tools there are proposed formulas for calculating some operational indicators and practic…
Control of solid-state fault current limiter for DG-integrated distribution systems
2017
Fault current limier (FCL) is a device that limits the system current under fault conditions without disconnecting the system and affecting the power system protection components such as circuit breakers. Many types of FCLs have been proposed to limit the magnitude of the fault current. Solid-state fault current limiters (SSFCLs) can limit the peak value of the fault current by applying several methods, such as controlling the system impedance or controlling the voltage that appears across the fault. In this paper, a new control scheme for the SSFCL circuit is presented. The control method is based on controlling the duty cycle of solid state switches to control the rms value of the system …
The Taguchi Method and Conditions for its Implementation in High Performance Athletic Training
2014
Abstract The purpose of this research is to present the main features of the Taguchi method, a method used today mainly in the optimization of industrial processes and products. It allows identification of process parameters that may contribute to system optimization; in our case, it allows the selection of the most effective means of training aimed at optimizing processes. After having determined the relevant characteristics in athlete training, we developed a model based on the Taguchi method, adapting the characteristics of that training for implementation in high performance athletic training. We also checked the optimum conditions for the implementation of management techniques and for…
Current and Voltage Behaviour During a Fault in a HV/MV System: Methods and Measurements
2015
When a single line to ground fault happens on the MV side of a HV/MV system, only a small portion of the fault current is injected into the ground by the ground-grid of the faulty substation. In fact the fault current is distributed between grounding electrodes and MV cables sheaths. In systems with isolated neutral or with resonant earthing this may be sufficient to provide safety from electric shock. Experimental measurements were performed on a real MV distribution network: a real single line to ground fault was made and fault currents were measured in the faulty substation and in four neighbouring substations. In this paper the problem of fault current distribution is introduced, the te…
A General Mathematical Model for non-Redundant Fault-Tolerant Inverters
2011
Industrial systems able to release trusted services is an integrated concept that resumes the attributes of availability, reliability, safety, integrity, and maintainability. In power electronics this can be aimed via the introduction of fault tolerant architectures. While In the past technical literature the mathematical modeling problem for non-redundant converters was fronted studying separately the cases of fault leg by leg, in this paper a general model able to include the three possible cases of leg faults with a unique set of equation is introduced and discussed. The same model allows to evaluate the DC Link transient and steady state evolution and also allows to develop with much ea…
A Technique for Power Supply Harmonic Impedance Estimation Using a Controlled Voltage Disturbance
2002
A method for power system impedance estimation is presented. The method employs a power converter to inject a voltage transient onto the supply system. As the technique employs controlled power electronic devices it may be used as a stand alone piece of a portable measurement equipment, or it may be embedded into the functions of an active shunt filter for improved harmonic control. The impedance is estimated through correlation of the measured voltage and current transients. Simulations and experimental results demonstrate the measurement technique is highly accurate and effective.
Flexible power converters for the fault tolerant operation of Micro-Grids
2010
The progressive penetration level of Distributed Generation (DG) is destined to cause deep changes in the existing distribution networks no longer considered as passive terminations of the whole electrical system. A possible solution is the realization of small networks, namely the Micro-Grids, reproducing in themselves the structure of the main production and distribution of the electrical energy system. In order to gain an adequate reliability level of the microgrids the individuation and the management of the faults with the goal of maintaining the micro-grid operation (fault tolerant operation) is quite important. In the present paper flexible power converters and a companion control al…
In sewer processes: mathematical model development and sensitivity analysis.
2009
Until now the majority of sewer networks in Italy have been built and managed considering small as well as local wastewater treatment plants (WWTPs). However, pushed by Italian and EU regulations, centralised and large WWTPs are becoming more common in Italy. One major technical aspect caused by the changing from local to centralised WWTPs is the development of significant in-sewer processes. These processes are also emphasized by the building of long interceptor sewers characterized by high hydraulic retention times and absence of tributary sewers. In this paper a model derived from the well known WATS model (Wastewater Aerobic/anaerobic Transformation in Sewers) has been set up and applie…
Stop there’s water on the road! Identifying key beliefs guiding people’s willingness to drive through flooded waterways
2016
Floods are among the most widespread of natural disasters and exposure to floodwaters increases drowning risk. A leading cause of flood related drowning deaths is driving through flooded waterways. Drawing on the Theory of Planned Behaviour, a two-phased research program was conducted. Phase 1 (N = 25; Mage = 32.38, SD = 11.46) identified common beliefs about driving through a flooded waterway. Phase 2 (N = 174; Mage = 27.43, SD = 10.76) adopted a cross-sectional design to examine the belief predictors of drivers' willingness to drive through a flooded waterway. Given differences in consequences due to the depth of water, scenarios of low (road covered in 20 cm of water) and high (road cove…
Psychometric Properties Of A Questionnaire Measuring The Antecedents Of Entrepreneurship Education Intention
2017
A limit of the questionnaires measuring Entrepreneurial Intention (EI) is the lack of a multidimensional vision of its antecedents. The definition of a multidimensional model of the main drivers affecting the intentions of aspiring entrepreneurs in building a start-up seems a fundamental milestone to overcome this pitfall. This paper aims to explore the internal consistency reliability of a new multidimensional questionnaire measuring the antecedents of EI and Entrepreneurial Education Intention (EEI). The tool consists in a self-administered online questionnaire that has been built in accordance with the Theory of Planned Behavior in entrepreneurship research. It includes 54 items adapted …