Update on the Design of a 1:33 Scale Model of a Modified Edinburgh Duck WEC

2008 ◽  
Author(s):  
Jorge Lucas ◽  
Joa˜o Cruz ◽  
Stephen Salter ◽  
Jamie Taylor ◽  
Ian Bryden
Keyword(s):  
Wave Energy ◽  
Control Strategies ◽  
Experimental Tests ◽  
Point Of View ◽  
Electricity Production ◽  
Scale Model ◽  
Random Waves ◽  
Numerical Predictions ◽  
Key Innovation ◽  
The University

A modified version of the Edinburgh Duck wave energy converter has been studied recently at the University of Edinburgh. From the design point of view the key innovation was a modification of the wetted profile. Wave energy is converted into useful work by the same pitching motion as in the original Duck, but by means of a circular cylinder with an off centred axis of rotation. This recent study was focused on a Duck version designed for vapour compression desalination rather than electricity production. An hydrodynamic numerical model (WAMIT) was used to predict first-order hydrodynamics quantities and to select and optimize configurations. The results obtained showed that it was possible, following the appropriate control strategies, to obtain similar energy absorption capabilities as the in the cam shaped original Duck. A 1:33 scale model was built to validate the numerical predictions. This paper extends the already published numerical predictions and experimental results obtained with this model. Experimental tests in random waves and measurements of the mooring forces for different submerged volumes will be reported for the first time.

Wave Energy Hyperbaric Device for Electricity Production

2007 ◽  
Author(s):  
Segen F. Estefen ◽  
Paulo Roberto da Costa ◽  
Eliab Ricarte ◽  
Marcelo M. Pinheiro
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Experimental Results ◽  
Electricity Production ◽  
Scale Model ◽  
Small Scale ◽  
Regular Waves ◽  
Hyperbaric Chamber ◽  
Small Scale Model

Wave energy is a renewable and non-polluting source and its use is being studied in different countries. The paper presents an overview on the harnessing of energy from waves and the activities associated with setting up a plant for extracting energy from waves in Port of Pecem, on the coast of Ceara State, Brazil. The technology employed is based on storing water under pressure in a hyperbaric chamber, from which a controlled jet of water drives a standard turbine. The wave resource at the proposed location is presented in terms of statistics data obtained from previous monitoring. The device components are described and small scale model tested under regular waves representatives of the installation region. Based on the experimental results values of prescribed pressures are identified in order to optimize the power generation.

Comparison of Mooring Loads in Survivability Mode on the Wave Dragon Wave Energy Converter Obtained by a Numerical Model and Experimental Data

2012 ◽  
Author(s):  
Stefano Parmeggiani ◽  
Made Jaya Muliawan ◽  
Zhen Gao ◽  
Torgeir Moan ◽  
Erik Friis-Madsen
Keyword(s):  
Numerical Model ◽  
Wave Energy ◽  
Complex Geometry ◽  
Wave Energy Converter ◽  
Scale Model ◽  
Coupled Analysis ◽  
Small Scale ◽  
Energy Converter ◽  
Numerical Predictions ◽  
Small Scale Model

The Wave Dragon Wave Energy Converter is ready to be up-scaled to commercial size. The design and feasibility analysis of a 1.5 MW pre-commercial unit to be deployed at the DanWEC test center in Hanstholm, Denmark, is currently ongoing. With regard to the mooring system, the design has to be carried out numerically, through coupled analyses of alternative solutions. The present study deals with the preliminary hydrodynamic characterization of Wave Dragon needed in order to calibrate the numerical model to be used for the mooring design. A hydrodynamic analysis of the small scale model in the frequency domain is performed by the software HydroD, which uses WAMIT as core software. The quadratic damping term, accounting for the viscous effect, is determined through an iterative procedure aimed at matching numerical predictions on the mooring tension, derived through time domain coupled analysis, with experimental results derived from tank tests of a small scale model. Due to the complex geometry of the device, a sensitivity analysis is performed to discuss the influence of the mean position on the quality of the numerical predictions. Good correspondence is achieved between the experimental and numerical model. The numerical model is hence considered reliable for future design applications.

scholarly journals Structural design and experimental tests on a model of tensegrity greenhouse prototype

2021 ◽  
Vol 52 (3) ◽  
Author(s):  
Giacomo Scarascia-Mugnozza ◽  
Silvana Fuina ◽  
Sergio Castellano
Keyword(s):  
Structural Steel ◽  
Fem Analysis ◽  
Experimental Tests ◽  
Scale Model ◽  
Average Percentage ◽  
Load Tests ◽  
Principles Of Design ◽  
Steel Weight ◽  
The University ◽  
Reduced Scale

The aim of this paper is the analysis, proposal and application of a structural tensegrity configuration for greenhouses supporting structures suitable for lightweight covering, based on principles of design coherence, material savings and building durability. By means of the FEM software, Sofistik®, a tensegral greenhouse prototype was modelled and designed in accordance with EN 13031-1:2019. In order to calibrate the results of the FEM analysis, experimental load tests and displacement measurements made with a tensegrity reduced scale model on a tensegrity reduced scale model, created at the Department laboratory of the University of Bari, were compared with the results of the calculation analysis. The displacements of the prototype selected nodes were detected by Target tracking Technology in two load configurations and a control transducer was positioned on the central structural node. The comparison among the displacements of the detected nodes with those resulting from the FEM software calculations, for two different load configurations, show average percentage errors of 7.1% and 12.55%. The results of the T test for the different load configuration point out that the two series of values experimentally detected and calculated by the software are not significantly different. Finally, results in terms of the structural steel weight and maximum stress of the tensegral structure were compared with those of commercial structures, both with vaulted roof and duopitched roof, of single span greenhouses having the same covered ground area of the greenhouse prototype. The proposed tensegrity greenhouse prototype showed a 9.6% and 35.2% reduction of the structural steel weight compared to the vaulted roof and to the duo-pitched roof greenhouse respectively.

scholarly journals 2DV RANS-VOF MODELLING OF DEPTHS AND VELOCITIES OF OVERTOPPING WAVES AT OVERWASHED DIKES

2012 ◽  
Vol 1 (33) ◽  
pp. 62 ◽  
Author(s):  
Andrea Natalia Raosa ◽  
Barbara Zanuttigh ◽  
Javier Lopez Lara ◽  
Steven Hughes
Keyword(s):  
Research And Development ◽  
Wave Energy ◽  
Wave Reflection ◽  
Experimental Tests ◽  
Engineer Research ◽  
Reflected Wave ◽  
The University ◽  
Development Center ◽  
The U.S ◽  
Sea Dikes

The purpose of this contribution is the representation of real wave overtopping over sea dikes with the Rans-Vof code (IH-2VOF) developed by the University of Cantabria. More specific objectives are: to identify the real capacity of the IH-2VOF model in the prediction of overflow and to determinate the accuracy of these predictions in order to provide designers with a generally applicable methodology to use the code. The model is validated against experimental tests conducted by Hughes at the U.S. Army Engineer Research and Development Center (ERDC). This analysis shows that the model tends to overestimate wave reflection and better results are obtained by introducing a porous layer around the structure as artificial way to reduce reflected wave energy.

Environmental cell studies of deformation and fracture

1990 ◽  
Vol 48 (4) ◽  
pp. 516-517
Author(s):  
H. K. Birnbaum ◽  
I. M. Robertson
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Damage Threshold ◽  
Chromatic Aberration ◽  
Good Choice ◽  
Point Of View ◽  
Deformation And Fracture ◽  
Environmental Cell ◽  
Gas Molecules ◽  
The University

Studies of the effects of hydrogen environments on the deformation and fracture of fcc, bcc and hep metals and alloys have been carried out in a TEM environmental cell. The initial experiments were performed in the environmental cell of the HVEM facility at Argonne National Laboratory. More recently, a dedicated environmental cell facility has been constructed at the University of Illinois using a JEOL 4000EX and has been used for these studies. In the present paper we will describe the general design features of the JEOL environmental cell and some of the observations we have made on hydrogen effects on deformation and fracture.The JEOL environmental cell is designed to operate at 400 keV and below; in part because of the available accelerating voltage of the microscope and in part because the damage threshold of most materials is below 400 keV. The gas pressure at which chromatic aberration due to electron scattering from the gas molecules becomes excessive does not increase rapidly with with accelerating voltage making 400 keV a good choice from that point of view as well. A series of apertures were placed above and below the cell to control the pressures in various parts of the column.

A Futures Study on the Quality Of Life from the Point Of View of Iranian Youth

2017 ◽  
Vol 14 (2) ◽  
pp. 1
Author(s):  
Sina Saeedy ◽  
Mojtaba Amiri ◽  
Mohammad Mahdi Zolfagharzadeh ◽  
Mohammad Rahim Eyvazi
Keyword(s):  
Quality Of Life ◽  
Life Satisfaction ◽  
Mixed Model ◽  
Satisfaction With Life ◽  
Point Of View ◽  
Human Society ◽  
Futures Studies ◽  
The Social ◽  
The University

Quality of life and satisfaction with life as tightly interconnected concepts have become of much importance in the urbanism era. No doubt, it is one of the most important goals of every human society to enhance a citizen’s quality of life and to increase their satisfaction with life. However, there are many signs which demonstrate the low level of life satisfaction of Iranian citizens especially among the youth. Thus, considering the temporal concept of life satisfaction, this research aims to make a futures study in this field. Therefore, using a mixed model and employing research methods from futures studies, life satisfaction among the students of the University of Tehran were measured and their views on this subject investigated. Both quantitative and qualitative data were analysed together in order to test the hypotheses and to address the research questions on the youth discontentment with quality of life. Findings showed that the level of life satisfaction among students is relatively low and their image of the future is not positive and not optimistic. These views were elicited and discussed in the social, economic, political, environmental and technological perspectives. Keywords:  futures studies, quality of life, satisfaction with life, youth

HIV/AIDS Knowledge and Risk-Taking Behaviours among Youths at a University in Enugu, Nigeria

2018 ◽  
Vol 20 (1) ◽  
Author(s):  
Ada C. Nwaneri ◽  
Okwudili Callistus Ezike ◽  
Agnes N. Anarado ◽  
Ifeoma Ndubisi ◽  
Jane-Lovena Onyia-Pat
Keyword(s):  
Risk Taking ◽  
Control Strategies ◽  
Analysis Of Covariance ◽  
Cross Sectional ◽  
Awareness Campaigns ◽  
South Eastern ◽  
Risky Behaviours ◽  
Aids Knowledge ◽  
The University ◽  
Hiv Aids

 A national sentinel survey of 2006 shows that Enugu State in south-eastern Nigeria is the worst hit by HIV infections. Despite numerous control strategies having been implemented, the state was still reported by another national HIV sentinel survey in 2010 as the worst hit by HIV/AIDS within the zone, and that youths are the most affected. The researchers conducted a cross-sectional descriptive survey to assess the HIV/AIDS knowledge and risk-taking behaviours of youths at a federal university in Enugu, south-eastern Nigeria. They adopted a multistage sampling method to recruit 460 unmarried, consenting students between 15 and 30 years of age, from three faculties of the university. Almost 90 per cent of the university youths had a sound knowledge of key concepts related to HIV/AIDS; despite this, a subset (7.39%) still engaged in risk-taking behaviours. The major risky behaviours identified include having premarital sex, having multiple sexual partners, the sharing of shaving or razor blades, the use of public clippers and tribal marking. Although an analysis of variance demonstrated no significant relationship (t = −0.036) between university youths’ knowledge of HIV/AIDS and their related risk-taking behaviour, risky behaviours were found to be more (13%) among respondents who had insufficient or incorrect knowledge of the disease. An analysis of covariance, however, showed that gender and socio-economic backgrounds were not determinants of the HIV/AIDS risk-taking behaviours of these youths. Therefore, factors such as attitude or culture are areas that should be focused on, and should then, along with educational awareness campaigns, help to reduce the spread and prevalence of the disease.

scholarly journals Impedance Matching-Based Power Flow Analysis for UPQC in Three-Phase Four-Wire Systems

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2702
Author(s):  
Xiaojun Zhao ◽  
Xiuhui Chai ◽  
Xiaoqiang Guo ◽  
Ahmad Waseem ◽  
Xiaohuan Wang ◽  
...  
Keyword(s):  
Power Flow ◽  
Control Strategies ◽  
Impedance Matching ◽  
Flow Analysis ◽  
Point Of View ◽  
Impedance Model ◽  
Power Flow Analysis ◽  
Three Phase ◽  
System Node ◽  
Power Quality Conditioner

Different from the extant power flow analysis methods, this paper discusses the power flows for the unified power quality conditioner (UPQC) in three-phase four-wire systems from the point of view of impedance matching. To this end, combined with the designed control strategies, the establishing method of the UPQC impedance model is presented, and on this basis, the UPQC system can be equivalent to an adjustable impedance model. After that, a concept of impedance matching is introduced into this impedance model to study the operation principle for the UPQC system, i.e., how the system changes its operation states and power flow under the grid voltage variations through discussing the matching relationships among node impedances. In this way, the nodes of the series and parallel converter are matched into two sets of impedances in opposite directions, which mean that one converter operates in rectifier state to draw the energy and the other one operates in inverter state to transmit the energy. Consequently, no matter what grid voltages change, the system node impedances are dynamically matched to ensure that output equivalent impedances are always equal to load impedances, so as to realize impedance and power balances of the UPQC system. Finally, the correctness of the impedance matching-based power flow analysis is validated by the experimental results.

scholarly journals Spirals of Sustainable Academic Motivation, Creativity, and Trust of Higher Education Staff

2021 ◽  
Vol 13 (13) ◽  
pp. 7057
Author(s):  
Martina Blašková ◽  
Dominika Tumová ◽  
Rudolf Blaško ◽  
Justyna Majchrzak-Lepczyk
Keyword(s):  
Higher Education ◽  
Academic Motivation ◽  
Slovak Republic ◽  
Point Of View ◽  
Scientific Management ◽  
Administrative Staff ◽  
Sustainable Systems ◽  
New Concepts ◽  
Future Improvement ◽  
The University

Sustainability has to penetrate more and more into higher education. It should not focus only on traditional elements. It should also enter new, but for future improvement, extremely important areas. Based on this premise, creativity and motivation, when additionally interconnected and supported by trust that is provided and achieved, decide on the progress and sustainability of universities. This connection is gaining importance especially from the point of view of building solid foundations and mechanisms that functionally preserve the potential effects of these elements in the future. For this reason and following the nature, importance, and content of sustainable academic motivation (SAM), the paper introduces two new concepts: sustainable academic creativity (SAC) and sustainable academic trust (SAT). For further original contributions, the paper hypothesizes the existence of mutual—spiral—relations of sustainable academic motivation (SAM), sustainable academic creativity (SAC), and sustainable academic trust (SAT). The empirical section tests the validity of this claim in the universities of two countries: the Slovak Republic and Poland. A survey performed on a sample of n=181 pedagogical, scientific, management, and administrative staff in higher education confirms the existence of these spirals. The results indicate the spiral effect of motivation when connected with creativity and trust and show that it is accented by the crucial principles of sustainability (responsibility, novelty, usefulness, progress, etc.). Therefore, the paper’s conclusion contains the explanations for the potential occurrence of three types of sustainably mutual systems and complexes. These are: (a) individual sustainable systems of SAM, SAC, and SAT; (b) group/sectional sustainable systems of SAM, SAC, and SAT; and (c) the global sustainable complex of SAM, SAC, and SAT in the university.

scholarly journals Experimental Methods for Measuring the Viscous Friction Coefficient in Hydraulic Spool Valves

2021 ◽  
Vol 13 (13) ◽  
pp. 7174
Author(s):  
Massimo Rundo ◽  
Paolo Casoli ◽  
Antonio Lettini
Keyword(s):  
Friction Coefficient ◽  
Viscous Friction ◽  
Experimental Tests ◽  
Experimental Methods ◽  
Displacement Transducer ◽  
A Posteriori ◽  
Displacement Control ◽  
Spool Valves ◽  
The University ◽  
Good Agreement

In hydraulic components, nonlinearities are responsible for critical behaviors that make it difficult to realize a reliable mathematical model for numerical simulation. With particular reference to hydraulic spool valves, the viscous friction coefficient between the sliding and the fixed body is an unknown parameter that is normally set a posteriori in order to obtain a good agreement with the experimental data. In this paper, two different methodologies to characterize experimentally the viscous friction coefficient in a hydraulic component with spool are presented. The two approaches are significantly different and are both based on experimental tests; they were developed in two distinct laboratories in different periods of time and applied to the same flow compensator of a pump displacement control. One of the procedures was carried out at the Fluid Power Research Laboratory of the Politecnico di Torino, while the other approach was developed at the University of Parma. Both the proposed methods reached similar outcomes; moreover, neither method requires the installation of a spool displacement transducer that can significantly affect the results.

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