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Wyszukujesz frazę "Martins, M." wg kryterium: Wszystkie pola


Tytuł:
Numerical evaluation of sound attenuation provided by periodic structures
Autorzy:
Martins, M.
Godinho, L.
Picado-Santos, L.
Powiązania:
https://bibliotekanauki.pl/articles/176630.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
traffic noise
sonic crystals
numerical method
Opis:
The use of periodic structures as noise abatement devices has already been the object of considerable research seeking to understand its efficiency and see to what extent they can provide a functional solu- tion in mitigating noise from different sources. The specific case of sonic crystals consisting of different materials has received special attention in studying the influence of different variables on its acoustic performance. The present work seeks to contribute to a better understanding of the behavior of these structures by implementing an approach based on the numerical method of fundamental solutions (MFS) to model the acoustic behavior of two-dimensional sonic crystals. The MFS formulation proposed here is used to evaluate the performance of crystals composed of circular elements, studying the effect of varying dimen- sions and spacing of the crystal elements as well as their acoustic absorption in the sound attenuation provided by the global structure, in what concerns typical traffic noise sources, and establishing some broad indications for the use of those structures.
Źródło:
Archives of Acoustics; 2013, 38, 4; 503-516
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An energy harvesting circuit for self-powered sensors
Autorzy:
Fernandes, J. R.
Martins, M.
Piedade, M.
Goncalves, H.
Powiązania:
https://bibliotekanauki.pl/articles/398011.pdf
Data publikacji:
2011
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
prostownik dwupołówkowy
odzyskiwanie energii
power-harvesting
full-wave rectifier
Opis:
In this work we present a prototype circuit to harvest energy from radio waves or through magnetic coupling based on a stack of full-wave rectifiers with transistors working on sub-threshold region. This circuit will use as an input a field-to-voltage converter capable of outputting a 200mV waveform and is able to self-start without any other energy sources. The circuit presented here is a proof of concept energy-harvesting circuit powering a low frequency ring oscillator which acts as the load. The circuit is designed, simulated and tested in a standard CMOS process, AMS CMOS 0.35 μm.
Źródło:
International Journal of Microelectronics and Computer Science; 2011, 2, 1; 1-5
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Traffic splitting in MPLS networks - a hierarchical multicriteria approach
Autorzy:
Craveirinha, J. M. F.
Cli'maco, J. C. N.
Pascoal, M. M. B.
Martins, L. M. R. A.
Powiązania:
https://bibliotekanauki.pl/articles/308582.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
multicriterial optimization
multicriteria shortest paths
routing telecommunication networks
Internet/MPLS
Opis:
In this paper we address a new hierarchical multicriteria routing model associated with a two-path traffic splitting routing method in MPLS networks whereby the bandwidth required by a given node-to-node traffic flow is divided by two disjoint paths. The model has two levels of objective functions and several constraints. An algorithmic approach is presented for calculating non-dominated solutions and selecting good compromise solutions to this problem. Also a number of computational experiments are presented.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 4; 3-10
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boundaries, Martins Axiom, and (P)-properties in dual Banach spaces
Autorzy:
Granero, Antonio S.
Hernández, Juan M.
Powiązania:
https://bibliotekanauki.pl/articles/745016.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Boundaries, Martin's Axiom, equality \(Seq(X^{**})=X^{**}\), super-(P) property
Opis:
Let \(X\) be a~Banach space and \(\mathcal{S} \mathit{eq}(X^{**})\) (resp., \(X_{\aleph_0}\)) the subset of elements \(\psi\in X^{**}\) such that there exists a~sequence \((x_n)_{n\geq 1}\subset X\) such that \(x_n\to \psi\) in the \(w^*\)-topology of \(X^{**}\) (resp., there exists a~separable subspace \(Y\subset X\) such that \(\psi\in \smash{{\overline{Y}^{w^*}}}\)). Then: (i) if \(\operatorname{Dens}(X)\geq \aleph _1\), the property \(X^{**}=X_{\aleph _0}\) (resp., \(X^{**}=\mathcal{S}\mathit{eq}(X^{**})\)) is \(\aleph _1\)-determined, i.e., \(X\)~has this property iff \(Y\) has, for every subspace \(Y\subset X\) with \(\operatorname{Dens}(Y)=\aleph _1\); (ii) if \(X^{**}=X _{\aleph _0}\), \( (B(X^{**}),w^*)\) has countable tightness; (iii) under the Martin's axiom \(\mathit{MA} (\omega _1)\) we have \(X^{**}=\mathcal{S}\mathit{eq}(X^{**})\) iff \((B(X^*),w^*)\) has countable tightness and \(\\overline {\text {co}}(B)=\overline {\text {co}} ^{w^*}(K)\) for every subspace \(Y\subset X\), every \(w^*\)-compact subset \(K\) of \(Y^*\), and every boundary \(B\subset K\).
Źródło:
Commentationes Mathematicae; 2016, 56, 1
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antioxidant enzymes activity affects Burkholderia sp. Ni tolerance
Autorzy:
Dourado-Ribeiro, M.
Franco, M.
Martins, P.
Peters, L.
Azevedo, R.
Powiązania:
https://bibliotekanauki.pl/articles/79826.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
antioxidative enzyme
nickel
water contamination
soil contamination
oxidative stress
reactive oxygen species
Burkholderia
bioremediation
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A multi-model approach to Saint-Venant equations: A stability study by LMIs
Autorzy:
Dos Santos Martins, V.
Rodrigues, M.
Diagne, M.
Powiązania:
https://bibliotekanauki.pl/articles/330130.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
równanie Saint-Venanta
system nieskończenie wymiarowy
stabilność wykładnicza
Saint-Venant equation
multi-model
LMIs
infinite dimensional system
exponential stability
strongly continuous semigroup
internal model boundary control
Opis:
This paper deals with the stability study of the nonlinear Saint-Venant Partial Differential Equation (PDE). The proposed approach is based on the multi-model concept which takes into account some Linear Time Invariant (LTI) models defined around a set of operating points. This method allows describing the dynamics of this nonlinear system in an infinite dimensional space over a wide operating range. A stability analysis of the nonlinear Saint-Venant PDE is proposed both by using Linear Matrix Inequalities (LMIs) and an Internal Model Boundary Control (IMBC) structure. The method is applied both in simulations and real experiments through a microchannel, illustrating thus the theoretical results developed in the paper.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 3; 539-550
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparative study on the performance of radiation detectors from the HgI2 crystals grown by different techniques
Autorzy:
Martins, J. F. T.
Costa, F. E.
dos Santos, R. A.
de Mesquita, C. H.
Hamada, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/146916.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
crystal growth
iodide mercury crystal
physical vapor transport (PVT)
radiation detector
semiconductor crystal
Opis:
In this work, the establishment of a technology for HgI2 purification and crystal growth is described, aiming at a future application of this crystal as a room temperature radiation semiconductor detector. Two methods of crystal growth were studied in the development of this work: (1) physical vapor transport (PVT) and (2) saturated solution from dimethylsulphoxide (DMSO) complexes. In order to evaluate the crystals obtained using each of these methods, systematic measurements were carried out for determining the stoichiometry, structure, orientation, surface morphology and impurity of the crystal. The influence of these physicochemical properties of the crystals developed was evaluated in terms of their performance as a radiation detector. The best response to radiation was found for the crystals grown by the PVT technique. Significant improvement in the performance of HgI2 radiation detector was found, purifying the crystal by means of two successive growths by the PVT technique.
Źródło:
Nukleonika; 2012, 57, 4; 555-562
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of an adaptive fuzzy variable structure compensator for the nonholonomic mobile robot in trajectory tracking task
Autorzy:
Begnini, M.
Bertol, W.
Martins, N. A.
Powiązania:
https://bibliotekanauki.pl/articles/971054.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
nonholonomic mobile robot
trajectory tracking
variable structure control
uncertainties and disturbances
fuzzy compensator
Lyapunov theory
Opis:
A robust adaptive kinematic control strategy, based on the methodology of variable structure control is considered in this paper. Because the dynamics of mobile robots is subject to uncertainties and disturbances, a fuzzy compensator is adopted to estimate them. In order to minimize the tracking errors and to attenuate the chattering phenomenon, an adaptation law for the fuzzy compensator is obtained by Lyapunov stability theory so as to asymptotically stabilize the control system as well as guarantee the convergence of the tracking errors. In terms of comparison with the boundary layer variable structure controller, simulations and experiments verify the feasibility and effectiveness of the proposed kinematic control strategy for the nonholonomic mobile robots under the incidence of uncertainties and disturbances.
Źródło:
Control and Cybernetics; 2018, 47, 3; 239-275
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scanning-Gate Microscopy of Semiconductor Nanostructures: An Overview
Autorzy:
Martins, F.
Hackens, B.
Sellier, H.
Liu, P.
Pala, M. G.
Baltazar, S.
Desplanque, L.
Wallart, X.
Bayot, V.
Huant, S.
Powiązania:
https://bibliotekanauki.pl/articles/2047914.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.23.Ad
03.65.Yz
85.35.Ds
Opis:
This paper presents an overview of scanning-gate microscopy applied to the imaging of electron transport through buried semiconductor nanostructures. After a brief description of the technique and of its possible artifacts, we give a summary of some of its most instructive achievements found in the literature and we present an updated review of our own research. It focuses on the imaging of GaInAs-based quantum rings both in the low magnetic field Aharonov-Bohm regime and in the high-field quantum Hall regime. In all of the given examples, we emphasize how a local-probe approach is able to shed new, or complementary, light on transport phenomena which are usually studied by means of macroscopic conductance measurements.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 569-575
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tailings reprocessing from Cabeco do Piao dam in Central Portugal: a kinetic approach of experimental data
Autorzy:
Figueiredo, J.
Vila, M. C.
Matos, K.
Martins, D.
Futuro, A.
de Lurdes Dinis, M.
Góis, J.
Leite, A.
Fiúza, A.
Powiązania:
https://bibliotekanauki.pl/articles/92190.pdf
Data publikacji:
2018
Wydawca:
Główny Instytut Górnictwa
Tematy:
tailings
multi-criteria optimization
reprocessing
zinc
tungsten
odpadki
optymalizacja wielokryterialna
utylizacja
cynk
wolfram
Opis:
The mining waste and tailing dam are object of discussion due to the accidents that occur due to a lack of control or due to interest in the remaining minerals present in these materials. Most of the old tailings dams have high contents of heavy metals which could represent potential risks to the environment or be an alternative source of some critical raw materials. The case study of the Cabeco do Piao dam in Central Portugal involved tailings from a processing plant that belonged to the Panasqueira Mine Complex, which has been in operation for over 120 years. Waste rock and mining tailings were deposited in the area until 1995, and they represent an environmental liability for the local population due to their high content of toxic metals. Tailings reprocessing can be considered as a solution that minimizes social and environmental impacts, recovers some essential minerals, such as Zn, W, and Cu which can help to offset investments made. The project design involves several stages of metal concentration, determined by experiments, as well as a model of the process. The overall model will take into account technological constraints, social-economic conditions and environmental impacts. A preliminary result of an optimization study of the kinetic approach is presented in this piece of work.
Źródło:
Journal of Sustainable Mining; 2018, 17, 3; 139-144
2300-1364
2300-3960
Pojawia się w:
Journal of Sustainable Mining
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study of Hough technique in surgery of otosclerosis, using the finite element method
Autorzy:
Gentil, F.
Parente, M.
Martins, P.
Santos, C.
Almeida, E.
Ferreira, A.
Natali, R.
Powiązania:
https://bibliotekanauki.pl/articles/307201.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
metoda elementów skończonych
otoskleroza
wycięcie strzemiączka
strzemiączko
finite element method
otosclerosis
stapedectomy
stapedotomy
stapes
Opis:
Purpose: Otosclerosis is a metabolic bone disease of the otic capsule that can cause the stapes fixation, resulting in conductive hearing loss or, in a profound sensorineural deafness threshold. Surgery is one of the possible treatments for the otosclerosis. To repair small focus of otosclerosis in the anterior crus of the stapes, in 1960, Hough suggested the implementation of a technique in which part of the anterior crus is fractured and the stapes turned. As a result, the posterior crus of the stapes is the only connection with the inner ear. In this work, the outcome of Hough’s surgical technique was simulated. Methods: Based on computerized images, a finite element model of middle ear ossicles and tympanic membrane was created, as well as a model where the stapes has changed. The discretization of the tridimensional solid model was made using the ABAQUS software. The mechanical properties used were taken from the literature and adequate boundary conditions were applied. Results: The results obtained with the Hough technique simulation were compared with a representative model of the normal ear, taking into account the displacements obtained on the central part of the stapes footplate and the maximum principal stress in the stapes crus. Conclusions: The results obtained are closer to the normal ear model, therefore Hough technique stands out as a good option to correct small focus of otosclerosis.
Źródło:
Acta of Bioengineering and Biomechanics; 2015, 17, 4; 149-153
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial Distribution and Diversity of Marine Zooplankton Adjacent to the St. Martins Island, Bangladesh
Autorzy:
Alam, Md. Jobaer
Kamal, A. S. M. Maksud
Ahmed, Md. Kawser
Khondker, Moniruzzaman
Fayyaz, Rafid
Powiązania:
https://bibliotekanauki.pl/articles/2202173.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
zooplankton
spatial distribution
abundance
richness
diversity
Bay of Bengal
St. Martin's Island
coastal water
Opis:
Bangladesh, a country that lies on the north shores of the Bay of Bengal, has been blessed with a plethora of natural resources. St. Martin’s Island, the only coral-bearing island in Bangladesh, is undoubtedly regarded as one of the most prized possessions. It is rich in biodiversity, but truly scientific information on it is lacking. In the present investigation, 14 stations adjacent to St. Martin’s Island within the Bay of Bengal were sampled for determining the composition, spatial distribution, species richness, and diversity of pelagic zooplankton. Samples were collected in the pre-monsoon hot season. From the community of zooplankton, 34 species were reported. Most of the species belonged to copepods. Besides, Polychaeta and Cirripedia were also present in the community. The most significant species belonged to Oithona, Canthocalanus, Balanus, Euterpina, and Microsetella. Total zooplankton standing crop varied from 45,000–125,000 ind/m3 and the highest number of species (8) were observed at station 7. Strong variability in the distribution of species was observed in the studied stations. The number of genera collected at each station varied from 4–8. Data on species richness (Df) varied from 1.30–3.04 and that of the Shannon-Wiener Index (H) from 1.33–1.93. The species composition of zooplankton and the species richness and the diversity index of the population was comparable to the other studies carried out in the Central and Western Bay of Bengal.
Źródło:
Journal of Ecological Engineering; 2022, 23, 10; 154--163
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementation of a pull system – a case study of a polymeric production system for the automotive industry
Autorzy:
Martins, Bruna
Silva, Cláudia
Silva, Diogo
Machado, Laura
Brás, Miguel
Oliveira, Rui
Carvalho, Tiago
Silva, Vera
Lima, Rui M.
Powiązania:
https://bibliotekanauki.pl/articles/2037393.pdf
Data publikacji:
2021
Wydawca:
STE GROUP
Tematy:
Kanban
Leveling
pull production
SMED
Supermarket
Opis:
This work, developed as a case study, propose, describe, and evaluates an implementation of a pull system in a SME company producing polymeric components for the automotive industry. The production system of the company was based on the push paradigm, which creates high stock levels and high lead times. The main purpose was to develop a pull production system controlled by Kanbans in the painting line. To achieve this goal, this case study demonstrates the application of relevant lean tools, such as, VSM, SMED, Kanban System, Supermarkets and Leveling. Through the SMED’s application, it was possible to reduce the setup times in 38% and make annual earnings of approximately 83000€. The application of a Kanban System, Leveling and Supermarket enabled the WIP’s reduction between injection and painting in 56% and, also, between painting and expedition in 45%. Also, the lead time decreased and the value-added time increased. Thus, this is an exemplary case study for the implementation of a pull system and can be used both by practitioners and researchers interested in this theme.
Źródło:
Management Systems in Production Engineering; 2021, 4 (29); 253-259
2299-0461
Pojawia się w:
Management Systems in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time domain reflectometry as a tool for the estimation of quality in foods
Autorzy:
Kent, M.
Knochel, R.
Daschner, F.
Schimmer, O.
Oehlenschlager, J.
Mierke-Klemeyer, S.
Barr, U.K.
Floberg, P.
Tejada, M.
Huidobro, A.
Nunes, L.
Batista, I.
Martins, A.
Powiązania:
https://bibliotekanauki.pl/articles/24653.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
fish product
fish
microwave
food
fish fillet
time domain reflectometry
quality
storage condition
Źródło:
International Agrophysics; 2004, 18, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Substrate Temperature Influenced Structural and Electrical Behaviour of~RF Magnetron Sputtered $Ag_2Cu_2O_3$ Films
Autorzy:
Sreedhar, A.
Hari Prasad Reddy, M.
Uthanna, S.
Martins, R.
Elangovan, E.
Pierson, J.
Powiązania:
https://bibliotekanauki.pl/articles/1492600.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.15.Mb
78.20.Ci
74.25.Gz
Opis:
$Ag_2Cu_2O_3$ films were deposited on glass and silicon substrates by RF magnetron sputtering of metallic equimolar $(Ag_{50}Cu_{50})$ alloy target in $Ar-O_{2}$ mixture at different substrate temperature $(T_{s})$ ranging between 303 and 523 K. The effect of $T_{s}$ on the core level binding energies, structural and electrical properties of the films was systematically studied. The films deposited at room temperature were amorphous. The films deposited at 373 K were polycrystalline and the crystallinity was increased when the $T_{s}$ was increased to 423 K. The films deposited at 423 K and subsequently annealed at 498 K exhibits single phase $Ag_2Cu_2O_3$. In the case of films deposited at higher $T_{s}$ of 523 K, $Ag_2O$ was decomposed into Ag. The electrical resistivity of the films deposited at 303 K was $1.2 \times 10^{-5}$ Ω cm, whereas the films formed at 423 K and subsequently annealed at 498 K showed electrical resistivity of $2.2 \times 10^{-3}$ Ω cm due to improvement in the crystallinity of single phase $Ag_2Cu_2O_3$.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-037-A-039
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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