Search results for "Absorber"

Firefly optimization used to identify hysteresis parameter on rotational MR-damper

2014

In his paper the physical properties and mathematical models of a semi-active magnetorheological (MR) damper is studied. The considered models are the Dahl model and Bouc-Wen model. The parameters for these models are found by using a firefly optimization algorithm that minimizes the difference between experimental and simulated data. The objective of his paper is to compare different mathematical MR-damper models with the experimental data. The simulation results illustrate he effectiveness of he proposed optimization algorithm.

Development of Kesterite (Cu2ZnSnS4) absorber material for solar cell application.

2021

Kesterite-based solar cells still suffer from limited efficiency due to various problems related to the absorber and device interfaces. Absorber defects and non-ideal band alignment at the absorber/buffer hetero-interface, resulting in a cliff-like conduction band offset (CBO), and non-ideal absorber/back contact interfaces are the main factors limiting efficiency.This thesis focuses mainly on the absorber-related problems such as the secondary phases and the band alignment at the absorber-buffer heterojunction as well as the back interface.In the first part, the properties of the absorber layer were studied. Thin layers of Cu2ZnSnS4 (CZTS) were obtained by chemical route. This study reveal…

A new solution for the sea wave exploitation. A linear ironless generator

2019

The exploitation of sea wave represents an important frontier for the energy sustainability in the next future. Despite the proposal of several techniques and solutions, commercial devices are not available. In this context, the Department of Engineering is investigating an innovative solution based on linear energy generators. This machine can be adopted as the main component in a wave energy converter, that is the device for the energy extraction of sea wave. Starting from an existing prototype, the paper examines the replacement of the iron stator with a non-magnetic material, in order to solve several common problems of linear generators, such as the cogging force. Results are reported,…

Renewable energy sources for energy consumption needs of Malta Island in Mediterranean sea

2016

The main purpose of this paper is to analyse the energetic condition of the Maltese islands and its electrical energy production, focusing on the employment of Renewable Energies in order to increase its energy independence. The main renewable source here proposed is wave energy: thanks to its strategic position, Malta will be able to produce electrical energy using an innovative type of Wave Energy Converter (WEC) based on the prototype of linear generator realized by University of Palermo. The use of this new technology will be able to cut down the electrical energy production from traditional power plants and, consequently, the greenhouse gases emissions (GHG). The procedures applied in …

Optimization of Wave Energy Converter: DEIM Point Absorber II

2018

The paper presents a possible solution to optimize a wave energy converter, device able to exploit the wave energy resource. The utilization of this technology shows also positive aspects, thanks to the limited visual and environmental impacts. This system could be also installed in reserved areas, being similar to signal buoys, simplifying the problem of energy supply in small islands. In order to exploit the wave energy potential in the Mediterranean Sea, the department of Energy of Palermo University realized a first prototype of the electrical linear generator, that is the main component of the wave energy converter. This electrical machine can be operated by a two-floating buoys system…

Effect of the anode composition on the performance of reversible chlor-alkali electro-absorption cells

2020

Abstract In this work, the performances of a reversible electrochemical cell for the storage of energy using the chloralkaline process was investigated. The cell operates at room temperature with liquid electrolytes in both compartments. In the electrolyzer mode, the cell transforms a sodium chloride solution into hydrogen and chlorine, which is then disproportionated to form hypochlorous acid and hypochlorite. In fuel cell operation mode, the cell becomes an electro-absorber to oxidize hydrogen at the anode while reducing hypochlorous acid at the cathode. Because of the low solubility of hydrogen, a special mechanical device is used to produce hydrogen microbubbles in the anodic compartmen…

Erratum: “Enhanced acoustic pressure sensors based on coherent perfect absorber-laser effect” [J. Appl. Phys. 129, 104902 (2021)]

2021

Transmission Attenuation Power Ratio Analysis of Flexible Electromagnetic Absorber Sheets Combined with a Metal Layer.

2018

Electromagnetic noise absorber sheets have become a solution for solving complex electromagnetic interference (EMI) problems due to their high magnetic losses. This contribution is focused on characterizing a novel structure that is based on an absorber film with a metal layer attached on its top side. Two different absorber compositions were combined with Al and Cu metal layers in order to study the improvement on the performance of these structures, depending on the complex permeability, absorber film thickness, and type of metal. The transmission attenuation power ratio of the absorber films is analyzed and compared to the performance of absorber and metal structures. The measurement pro…

ZnS Ultrathin interfacial layers for optimizing carrier management in Sb2S3-based photovoltaics

2021

Antimony chalcogenides represent a family of materials of low toxicity and relative abundance, with a high potential for future sustainable solar energy conversion technology. However, solar cells based on antimony chalcogenides present open-circuit voltage losses that limit their efficiencies. These losses are attributed to several recombination mechanisms, with interfacial recombination being considered as one of the dominant processes. In this work, we exploit atomic layer deposition (ALD) to grow a series of ultrathin ZnS interfacial layers at the TiO2/Sb2S3 interface to mitigate interfacial recombination and to increase the carrier lifetime. ALD allows for very accurate control over th…

Systemic analysis of the caulking assembly process

2017

The present paper highlights the importance of a caulking process which is nowadays less studied in comparison with the growing of its usage in the automotive industry. Due to the fact that the caulking operation is used in domains with high importance such as shock absorbers and brake systems there comes the demand of this paper to detail the parameters which characterize the process, viewed as input data and output data, and the requirements asked for the final product. The paper presents the actual measurement methods used for analysis the performance of the caulking assembly. All this parameters leads to an analysis algorithm of performance established for the caulking process which it …