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Line of sight waypoint guidance for a container ship based on frequency domain identification of Nomoto model of vessel

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Journal of Central South University 2016年第8期23卷 1944-1953页

作者： M.T.Ghorbani instituto superior tecnico Torre Norte-8.17 1049-001 Lisboa Portugal

CIFER software is used to identify steering and roll dynamics of a container ship. In this software, advanced features such as the Chirp-Z transform(CZT) and composite window optimization are applied to the time history of steering and roll dynamics to extract high quality frequency responses. From the extracted frequency responses, two linear transfer functions of Nomoto model are fitted for yaw and roll dynamics of the vessel. Based on the identified Nomoto model, a Pid heading controller and a Kalman filter observer are constructed. The simulation results of heading controller for line of sight(LOS) waypoint guidance show excellent tracking of pilot inputs in the presence of wave induced motions and forces.

关键词： container ship Nomoto model Kalman filter frequency domain identification CIFER software

Analysis of a passive ankle exoskeleton for reduction of metabolic costs during walking

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Defence Technology（防务技术） 2024年第7期37卷 62-68页

作者： Luís Quinto Pedro Pinheiro Sergio B.Goncalves Ivo Roupa Paula Simoes Miguel Tavares da Silva CINAMIL Academia MilitarInstituto Universitario MilitarLisbonPortugal idMEC Instituto Superior TecnicoUniversidade de LisboaLisbonPortugal

Modern conflicts demand substantial physical and psychological exertion,often resulting in fatigue and diminished combat or operational *** exoskeletons have been developed recently to address these challenges,presenting various limitations that affect their operational or everyday *** article evaluates the performance of a dual-purpose passive ankle exoskeleton developed for the reduction of metabolic costs during walking,seeking to identify a force element that could be applied to the target *** on the 6-min walk test,twenty-nine subjects participated in the study using three different force *** results indicate that it is possible to reduce metabolic expenditure while using the developed ***,the comfort and range of motion results verify the exoskeleton's suitability for use in uneven terrain and during extended ***,the choice of the force element should be tailored to each user,and the control system should be adjustable to optimise the exoskeleton's performance.

关键词： Ankle passive exoskeleton Metabolic cost reduction Dual-use exoskeleton Gait Biomechanics

Optimal distribution of active piezoelectric elements for noise attenuation in sandwich panels

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International Journal of Smart and Nano Materials 2020年第4期11卷 400-416页

作者： J.F.A.Madeira A.L.Araujo idMEC Instituto Superior TecnicoUniversidade de LisboaLisboaPortugal ADM ISELInstituto Politecnico de LisboaLisboaPortugal

In this paper,a multiobjective optimization approach for obtaining the optimal distribution of surface-bonded piezoelectric sensors and actua-tors for noise attenuation in sandwich panels is *** noise attenuation is achieved by using negative velocity feedback control with co-located sensors and *** control gains are also optimized in order to obtain the most efficient noise attenuation in a given frequency *** in-house implementation of a viscoelastic soft core sandwich plate finite element,including surface-bonded piezoelectric sensors and actuators with active control capabilities,is used for obtaining the frequency response of the *** sound transmission capability of the panels is evaluated using the radiated sound power,along with the Rayleigh integral approach,which is suitable for lightly coupled structural/acoustic *** Direct MultiSearch(DMS)optimization algorithm is used to minimize the added weight due to the piezoelectric material,minimizing also the number of required controllers and maximizing the noise *** total length of the radiated sound power curve is shown to be an effective measure of noise attenuation in a given frequency ***-off Pareto fronts and the obtained optimal configurations are presented and discussed.

关键词： Sandwich structures piezoelectricity viscoelasticity active damping multiobjective optimization

Mathieu Progressive Waves

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Communications in Theoretical Physics 2011年第10期56卷 733-739页

作者： Andrei B.Utkin INOV-inesc Inovacao Rua Alves Redol 9Lisbon 1000-029Portugal ICEMSInstituto Superior TecnicoTecnical University of LisbonAv.Rovisco Pais 1Lisbon 1049-001Portugal

A new family of exact solutions to the wave equation representing relatively undistorted progressive waves is constructed using separation of variables in the elliptic cylindrical coordinates and one of the Bateman transforms. The general form of this Bateman transform in an orthogonal eurvilinear cylindrical coordinate system is discussed and a specific problem of physical feasibility of the obtained solutions, connected with their dependence on the cyclic coordinate, is addressed. The limiting case of zero eccentricity, in which the elliptic cylindrical coordinates turn into their circular cylindrical counterparts, is shown to correspond to the focused wave modes of the Bessel-Gauss type.

关键词： wave equation Bateman transform progressive wave Mathieu function

Electrochemical properties of AB_5 type hydrogen storage alloy as anode electrocatalyst of PEMFC

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中国有色金属学会会刊：英文版 2005年第2期15卷 361-365页

作者：陈昀王新华陈长聘陈立新 C.A.C.Sequeira Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 ChinaDepartment of Chemical Engineering Instituto Superior Tecnico Lisbon 1049-001 Portugal Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China Department of Chemical Engineering Instituto Superior Tecnico Lisbon 1049-001 Portugal

The electrocatalytic properties of hydrogen storage alloy（HSA） MlNi3.65Co0.85Al0.3Mn0.3 substituting Pt as anode electrocatalyst of PEMFC was investigated. It is found that, after being optimized, the electrocatalytic abilities of the HSA is reasonably good, the current density of the HSA anode membrane and electrode assembly（MEA） reaches 168 mA/cm2 at 0.5 V and 232.4 mA/cm2 at 0.2 V, and its power density reaches the maximum value of 84 mW/cm2. The influence of operating temperature and hydrogen pressure on the electrocatalytic behavior of HSA anode MEA is also discussed. At 60 ℃ under 2.02×105 Pa H2, the HSA anode shows the best electrochemical properties.

关键词：储氢合金镍钴锰合金燃料电池电化学性质

Dynamics of Droplets of Biological Fluids on Smooth Superhydrophobic Surfaces under Electrostatic Actuation

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Journal of Bionic Engineering 2016年第2期13卷 220-234页

作者： Ana Sofia Moita Catarina Laurencia Joana Anastacio Ramos Duarte Miguel Franca Prazeres Antonio Luis Nobre Moreira IN+ - Center for Innovation Technology and Policy Research Instituto Superior Tecnico Universidade de Lisboa Av. Rovisco Pais 1049-001 Lisboa Portugal iBB - Institute for Bioengineering and Biosciences Department of Bioengineering Instituto Superior Tecnico Universidade de Lisboa Av. Rovisco Pais 1049-001 Lisboa Portugal

This study describes the dynamic behaviour of droplets of biological liquids on hydrophobic surfaces under electrostatic actuation, to devise sample handling in lab-on-chip diagnostic tools. Bovine Serum Albumin （BSA） is taken as a representative biomolecule, since it is often used in adsorption studies. Green Fluorescence Protein （GFP） is also considered, given its natural fluorescence. Several effects such as sample concentration and pH are discussed. The results show negligible effects of proteins concentration in electrowetting, although increased concentrations endorse passive adsorption mechanisms, which alter the local wettability of the substrates precluding droplet motion. Bioinspired surfaces promote the largest spreading diameter, which is beneficial for droplet motion. However, surface roughness promotes energy dissipation limiting the receding droplet motion. Hence, the most effective approach is altering the surface chemistry. The coating is applied to a surface with a mean roughness smaller than 20 nm and does not alter significantly the topography, thus leading to the so-called smooth superhydrophobic surface. This coating also reduces passive proteins adsorption, as confirmed by Confocal Microscopy （CM）, which is beneficial for droplet motion. Evaluating absorption spectra of protein solutions evidences an increase in protein concentration ascribed to droplet evaporation as confirmed by theoretical analysis and time resolved infrared visualization.

关键词： bioinspired surfaces biofluids electrostatic actuation hydrophobicity adsorption evaporation

Does the smartest designer design better？ Effect of intelligence quotient on students＇ design skills in architectural design studio

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Frontiers of Architectural Research 2015年第4期4卷 318-329页

作者： Sajjad Nazidizaji Ana Tome Francisco Regateiro CERIS DECivil Instituto Superior Tecnico Universidude de Lisboa Lisboa 1049-001 Portugal

Understanding the cognitive processes of the human mind is necessary to further learn about design thinking processes. Cognitive studies are also significant in the research about design studio. The aim of this study is to examine the effect of designers intelligence quotient （lOJ on their designs. The statistical population in this study consisted of all Deylaman Institute of Higher Education architecture graduate students enrolled in 2011. Sixty of these students were selected via simple random sampling based on the finite population sample size calculation formula. The students＇ IQ was measured using Raven＇s Progressive Matrices. The students＇ scores in Architecture Design Studio （ADS） courses from first grade （ADS-l） to fifth grade （ADS-5） and the mean scores of the design courses were used in determining the students＇ design ability. Inferential statistics, as well as correlation analysis and mean comparison test for independent samples with SPSS, were also employed to analyze the research data. Results indicated that the students＇ IQ ADS-1 to ADS-4 scores, and the mean scores of the students＇ design courses were not significantly correlated. By contrast, the students＇ IQ and ADS-5 scores were significantly correlated. As the complexity of the design problem and designers＇ experience increased, the effect of IQ on design seemingly intensified.

关键词： Architectural designstudio Intelligence quotient(IQ) Design education Human factors Design thinking

Search for desisn intellisence： A field study on the role of emotional intellisence in architectural design studios

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Frontiers of Architectural Research 2014年第4期3卷 413-423页

作者： Sajjad Nazidizaji Ana Tome Francisco Resateiro ICIST DECivil Instituto Superior Tecnico Universidade de Lisboo Avenida Rovisco Pais 1Lisboa 1049-001 Portugal CESUR DECivil Instituto Superior Tecnico Universidade de Lisboa Avenida Rovisco Pais ILisboa 1049-001 Portugal

The design studio is the core of the architecture curriculum. Interpersonat interactions have a key rote during the processes of design and critique. The influence of emotional intelligence （EQ） on interpersonal communication skirts has been widely proven. This study examines the correlation between EQ and architecturat design competence, To achieve this, 78 architecture students were setected via a simple random sampling method and tested using an EO. test questionnaire developed by Bradbury and Greaves （2006）. The scores of five architectural design studio courses （ADS-1, ADS-2, ADS-3, ADS-4, and ADS-5） were used as indicators of the progress in design of the students. Descriptive and inferential statistics methods were both employed to anatyze the research data. The methods inctuded corretation analysis, mean comparison t-test for independent samptes, and single sample t-test. Findings showed no significant relationship between EQ and any of the indicators.

关键词： Emotional intelligence (EQ) Architectural education Design competence Design studio

Effect of pier shape and pier alignment on the equilibrium scour depth at single piers

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International Journal of Sediment Research 2016年第3期31卷 244-250页

作者： Cristina Fael Rui Lana António Cardoso Faculdade de Engenharia Universidade da Beira InteriorEdificio Ⅱ das EngenhariasCalcada Fonte da Lameiro instituto superior de Engenharia/Universidade do Algarve instituto superior tecnico Universidade de Lisboa

The equilibrium scour depth at uniform single bridge piers depends on a large number of variables,including the pier horizontal cross-section shape and its alignment angle towards the flow *** influence of these variables has been studied by only a few researchers,mostly,on the basis of tests that were far from approaching *** experimental study aims at revisiting the influence of piers’ shape and alignment on local scouring for length-width ratios smaller than or equal to 4,by increasing the experimental *** five long-duration laboratory tests were run under steady,clear-water flow,close to the threshold for initiation of sediment *** pier shapes were considered:circular,rectangular square-nosed,rectangular round-nosed,oblong,and zero-spacing(packed) pile-groups;the tested skew-angles were 0°,30°,45°,60°,and 90°.It was concluded that i) the shape factor can be taken as 1.0,for rectangular round-nosed and oblong cross-section piers,and as 1.2,for rectangular squarenosed and packed pile-group cross-section piers,ii) the shape factor does not vary significantly with the duration of tests,this way confirming the robustness of the shape factors reported to date,iii) the effect of shape is present at skewed piers although the associated coefficients remain in the narrow range of1.0-1.2,and iv) for length-width ratios smaller than 4,the shape factor is of the same order of magnitude as the skew angle factor and should not be neglected.

关键词： Scour Pier shape Pier alignment