Search results for "TRANSFORMATION"

Finite difference thermal model of a latent heat storage system coupled with a photovoltaic device: Description and experimental validation

2014

Abstract The use of photovoltaic (PV) systems has been showing a significant growth trend but for a more effective development of this technology it is essential to have higher energy conversion performances. Producers of PV often declare an higher efficiency respect to real conditions and this deviation is mainly due to the difference between nominal and real temperature conditions of the PV. To improve the solar cell energy conversion efficiency many authors have proposed a methodology to keep lower the temperature of a PV system: a modified PV system built with a normal PV panel coupled with a Phase Change Material (PCM) heat storage device. In this paper is described a thermal model ana…

Novel test bed for induction heating power supplies

2006

Power supplies used in induction heating industrial applications must be entirely tested after its manufacturing in order to assure its security and reliability by means of a full power running test of several hours of duration. Nowadays this test is done with a dissipative load which implies a large waste of energy. This paper proposes a new high efficiency test system for induction heating generators. It incorporates a regenerative electronic load which allows an extraordinary improvement of the efficiency of this test with an important economical and ecological benefit.

Feasibility issues in static output-feedback controller design with application to structural vibration control

2014

Recent results in output-feedback controller design make possible an efficient computation of static output-feedback controllers by solving a single-step LMI optimization problem. This new design strategy is based on a simple transformation of variables, and it has been applied in the field of vibration control of large structures with positive results. There are, however, some feasibility problems that can compromise the effectiveness and applicability of the new approach. In this paper, we present some relevant properties of the variable transformations that allow devising an effective procedure to deal with these feasibility issues. The proposed procedure is applied in designing a static…

Oxidation of secondary alcohols by duckweed: A biotransformation experiment for undergraduate students

1988

A small scale prototype of a wave energy conversion system for hydrogen production

2015

In this paper a small scale prototype of sea wave energy converter for hydrogen production and storage is presented. Laboratory prototypes of the wave energy converter device and sea water electrolyzer are presented. Experimental results are shown. A cost-effective and efficient power electronics system is designed. Experimental waveforms of the wave energy converter are imported in the power electronics simulation model to simulate the whole system as closely as possible to its effective behavior. Simulation results are shown to test the efficiency of the proposed solution.

Design issues for wind farms grid tied Inverter

2017

In this paper the Authors give indications for the design of a grid tied Voltage Source Inverters (VSI) aimed to optimal use in energy conversion from wind source. In particular, the design of the inverter is more focused on the control system planning, with a particular glance on the grid synchronization problem. After the exposition of general issues concerning renewable energies and associated topics, the case of a grid tied inverter is considered and a methodology of design is sketched starting from the consideration of the DC side and also considering the power device losses, the protection issue against over voltages and over-currents, snubber circuits, heat sinks and, finally the con…

A Hybrid Machine Learning and Knowledge Based Approach to Limit Combinatorial Explosion in Biodegradation Prediction

2016

One of the main tasks in chemical industry regarding the sustainability of a product is the prediction of its environmental fate, i.e., its degradation products and pathways. Current methods for the prediction of biodegradation products and pathways of organic environmental pollutants either do not take into account domain knowledge or do not provide probability estimates. In this chapter, we propose a hybrid knowledge-based and machine learning-based approach to overcome these limitations in the context of the University of Minnesota Pathway Prediction System (UM-PPS). The proposed solution performs relative reasoning in a machine learning framework, and obtains one probability estimate fo…

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…

Experimental Test and Simulations on a Linear Generator-Based Prototype of a Wave Energy Conversion System Designed with a Reliability-Oriented Appro…

2017

In this paper, we propose a reliability-oriented design of a linear generator-based prototype of a wave energy conversion (WEC), useful for the production of hydrogen in a sheltered water area like Mediterranean Sea. The hydrogen production has been confirmed by a lot of experimental testing and simulations. The system design is aimed to enhance the robustness and reliability and is based on an analysis of the main WEC failures reported in literature. The results of this analysis led to some improvements that are applied to a WEC system prototype for hydrogen production and storage. The proposed WEC system includes the electrical linear generator, the power conversion system, and a sea-wate…

Relación entre los estilos de Liderazgo Transformacional y Laissez-faire y el Síndrome de Quemarse por el Trabajo en profesores de educación secundar…

2018

Introducción: los objetivos del estudio fueron los siguientes: (1) analizar la influencia de los estilos de Liderazgo Transformacional (LT) y Laissez-faire (LLF) sobre el Síndrome de Quemarse por el Trabajo (SQT); (2) evaluar la influencia de las dimensiones de LT (Carisma o Influencia idealizada, Inspiración, Estimulación intelectual y Consideración individualizada) sobre las dimensiones de SQT Perfil 1 (Ilusión por el trabajo, Desgaste psíquico e Indolencia).Material y métodos: la muestra estuvo formada por 211 profesores portugueses de educación secundaria (28.9% hombres y 71.1% mujeres). LT (Carisma o Influencia idealizada, Inspiración, Estimulación intelectual y Consideración individua…