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Wyszukujesz frazę "Fernandes, J." wg kryterium: Autor


Wyświetlanie 1-14 z 14
Tytuł:
A comparative study on transformer and inductor based LC tanks for VCOs
Autorzy:
Duarte, R.
Fernandes, J. R.
Powiązania:
https://bibliotekanauki.pl/articles/397839.pdf
Data publikacji:
2010
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
RF (częstotliwość radioelektryczna)
VCO (generator sterowany napięciowo)
RF (radio frequency)
VCO ( voltage controlled oscillators)
PLL
Opis:
This paper presents a detailed comparative study of two different approaches to implement the resonator found in radio frequency (RF) voltage controlled oscillators (VCOs). An inductor LC tank VCO and a transformer LC tank VCO are compared in terms of phase noise, power consumption, tuning range and circuit area. Conclusions about the use of each approach depending on the design goals are presented.
Źródło:
International Journal of Microelectronics and Computer Science; 2010, 1, 1; 37-41
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigating biomechanical function of toes through external manipulation integrating analysis
Autorzy:
Mei, Q.
Fernandes, J.
Hume, P.
Gu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/306943.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
palec nogi
uchwyt
przyczepność
uszkodzenia
toes
grip
windlass mechanism
metatarsal injury
Opis:
Purpose: This study was aimed to investigate the function of toes while running through comparing bound toes by external-manipulation with natural separate toes by evaluating kinematics and plantar pressure analysis. Methods: Seven habitually barefoot male runners participated in the running test under toes binding and non-binding conditions, and Vicon and Novel insole plantar pressure measurement were conducted synchronously to collect kinematics and foot loading. Results: Ankle kinematics showed larger non-significant range of motion in the frontal plane while running with toes non-binding.The medial forefoot had a smaller force time integral, and with hallux had a larger force time integral than those of running with toes binding, with significance level p < 0.05. Conclusions: While no significance existed between bound and non-bound toes in kinematics, the medial forefoot had a smaller foot impulse and the hallux had a larger foot impulse for those with non-binding feet. This suggests that other functions such as the active gripping action of toes might be important for the efficiency of the foot windlass mechanism (the plantar fascia support), which would be beneficial for running performance improvement and foot injury prevention.
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 1; 97-102
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
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:
Thermal assisted switching magnetic tunnel junctions as FPGA memory elements
Autorzy:
Silva, V.
Fernandes, J. R.
Oliveira, L. B.
Neto, H. C.
Ferreira, R.
Freitas, S.
Freitas, P. P.
Powiązania:
https://bibliotekanauki.pl/articles/397855.pdf
Data publikacji:
2010
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
MRAM (oporność magnetyczna pamięci o dostępie swobodnym)
MTJ (magnetyczny tunel połączeń)
pisanie projektów (programów)
FIMS (pole indukowane magnetycznym przełącznikiem)
MRAM (magnetoresistive random access memory)
MTJ (magnetic tunnel junction)
writing schemes
FIMS (field induced magnetic switching)
TAS (thermal assisted switching)
STT
Opis:
This paper presents our research and development work on new circuits and topologies based on Magnetic RAM for use as configuration memory elements of reconfigurable arrays. MRAM provides non volatility with cell areas and with access speeds comparable to those of SRAM and with lower process complexity than FLASH memories. The new memory cells take advantage of the Thermal Assisted Switching (TAS) writing technique to solve the drawbacks of the more common Field Induced Magnetic Switching writing technique. The CMOS circuit structures to implement the main components for reading and writing the MTJ cells have been developed, characterized and evaluated. A scaled down prototype of a coarse grain reconfigurable array that employs the TAS-MRAM elements as configuration memory has been designed and electrically simulated pre- and post- layout. The results obtained for all the circuit elements, namely the storage cells and the current generators, indicate that the new configuration memory cells can provide a very promising technological solution for run-time reconfigurable hardware devices. The prototype has been manufactured using a standard process 0.35μm 4-Metal CMOS process technology and should be under test in the foreseeable future.
Źródło:
International Journal of Microelectronics and Computer Science; 2010, 1, 1; 31-36
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Representativeness of Offensive Scenarios to Evaluate Perceptual-Cognitive Skills of Water Polo Players
Autorzy:
Casanova, Filipe
Pereira, Ricardo
Canossa, Sofia
Padilha, Maickel
Bagatin, Rafael
Teoldo, Israel
González-Víllora, Sixto
Fernandes, Ricardo J.
Tavares, Fernando
Powiązania:
https://bibliotekanauki.pl/articles/1030822.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
Attacking Game Scenarios
Water Polo
decision-making
reliability
Opis:
The aim of this study was to trial several attacking offensive sequences as representative for further use in research on the perceptual-cognitive skills of water polo players. Elite water polo coaches were presented with separate test film sequences encompassing 80 structured water polo offensive plays. Each clip was approximately 6 s–7 s long with an inter-clip interval of 5 s–10 s, where a red dot was displayed on-screen at the start of the clip to indicate the area of first appearance of the ball. The order of presentation of the video clips was counterbalanced and randomly determined. The criteria were scored on a 5-point Likert-type scale. From the 80 clips presented, only 56 showed high agreement (W = 1; p < 0.05) and internal consistence reliability between the expert observers (α = 0.980; p < 0.05). Furthermore, a very high reproducibility (Z = 0; p = 1) was obtained between viewing sessions. The results obtained determine that 56 offensive scenarios were representative of the water polo game and as such may be useful in evaluating the perceptual-cognitive skills of the players.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2020, 29, 1; 11-19
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integrated Dynamometric, Kinematic And Electromyographic Characterisation Of A Swimming Track Start Block Phase – A Pilot Study
Autorzy:
Vitor, Manuel
de Jesus, Karla
Mourão, Luís
Tribuzi, Sara
Gonçalves, Pedro
Marques, Mariana
Roesler, Hélio
Vaz, Mário
Vilas-Boas, João Paulo
Fernandes, Ricardo J.
Powiązania:
https://bibliotekanauki.pl/articles/1054777.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
biomechanics
dynamometry
kinematics
electromyography
swimming
Opis:
This study presents a complete biomechanical analysis of the block phase of a swimming modified track start. Kinetic, kinematic and electromyography (EMG) data were collected. The forces produced by the swimmer on the block, the EMG of eight muscles and the kinematics of the centre of mass (CM) were recorded. A national-level swimmer performed three repetitions of a track start in a dynamometric starting block. Temporal instants ‘reaction time’, ‘hands take-off’, ‘rear foot take-off’ and ‘front foot take-off’ were identified. Results show the peak forces (Fmax) produced by the most dynamic limb in each sub-phase delimited by mentioned instants (right hand take-off: Fmaxvertical = 103 N; rear foot take-off: Fmaxantero-posterior = 524 N; front foot take-off: Fmaxvertical = 634 N). The CM revealed a descendent vertical trajectory along the block phase. Mean resultant speed at front foot take-off was 4.092m/s. The muscles with highest values of integral EMG (iEMG) were the tibialis anterior during hands take-off, Biceps Femoris and Gluteus Maximus during rear foot take-off, respectively 41.17%, 52.96% and 36.37% of the maximum isometric voluntary contraction (%MIVC). The study demonstrates an effective characterisation of the block phase in swimming starts with potential to evaluate the swimmers performance in the track start, using different back plate positioning.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2016, 15, 3; 5-14
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, characterization and catalytic properties of SAPO-11 molecular sieve synthesized in hydrothermal media using di-isopropylamine as template
Autorzy:
Chellappa, T.
Costa, M. J. F.
Nascimento, W. A.
Ferreira De Lima, L.
Bassan, I. A.
Tavares, M.
Fernandes, V. J.
Menezes, A.
Guilherme Meira, L.
Telesforo Nóbrega De Medeiros, J.
Maribondo Do Nascimento, R.
Powiązania:
https://bibliotekanauki.pl/articles/200372.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microporous materials
SAPO-11
characterization
catalytic activity
molecular sieves
Opis:
A microporous SAPO-11 Molecular sieve was successfully synthesized by the hydrothermal method, using a single agent, as an organic template: di-isopropylamine (DIPA). The obtained solid was calcined at 550C for three hours, after which the flow of nitrogen was exchanged for that of synthetic air and submitted for another ten hours of calcination, so as to remove the single agent: di-isopropylamine, which after the removal of the template could be observed by the high crystallization of the sample. Furthermore, the molecular sieve was characterized by XRD, SEM, TG-DTG and N2 adsorption desorption (BET analysis). The obtained catalyst proved to have a high potential catalytic activity and selectivity, through the obtained characterization results, exhibiting good hydrothermal stability. The catalytic performance of SAPO-11 was tested by the deactivation/regenerability of the coked sample, furthered by cracking of n-hexane reaction and high olefins selectivity was obtained.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 3; 481-488
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Solution of a Finite Element Approximation of a Linear Obstacle Plate Problem
Autorzy:
Fernandes, L. M.
Figueiredo, I. N.
Judice, J. J.
Powiązania:
https://bibliotekanauki.pl/articles/907894.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
matematyka
variational inequality
complementarity problem
contact problem
Opis:
In this paper the solution of a finite element approximation of a linear obstacle plate problem is investigated. A simple version of an interior point method and a block pivoting algorithm have been proposed for the solution of this problem. Special purpose implementations of these procedures are included and have been used in the solution of a set of test problems. The results of these experiences indicate that these procedures are quite efficient to deal with these instances and compare favourably with the path-following PATH and the active-set MINOS codes of the commercial GAMS collection
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 1; 27-40
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water-based poly(urethane-urea) dispersions —meeting the European Union legislation
Dyspersje wodne poli(uretanowo-mocznikowe) w świetle wymagań prawodawstwa Unii Europejskiej
Autorzy:
Fernandes, I. P.
Costa, M. R.
Ferreira, M. J.
Barreiro, M. F.
Powiązania:
https://bibliotekanauki.pl/articles/947121.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
poly(urethane-urea)
water-based dispersion
European Union legislation
N-methyl-pyrrolidone free products
poli(uretano-mocznik)
dyspersja wodna
prawodawstwo Unii Europejskiej
produkty wolne od N-metylo-pirolidonu
Opis:
This article discusses the synthesis methods of water-based poly(urethane-urea) dispersions (PUD), which over the past few decades have developed a solid reputation for high performance applications, particularly in the field of adhesives and coatings. PUDs are mostly environmentally compatible products since they do not contain or contain only low amounts of volatile organic compounds (VOC). This is an important feature in view of the present environmental policies, where governments and internal agencies are placing emphasis on developing sustainable processes, improving work conditions and reducing emissions of toxic and polluting substances into the atmosphere. In this context, this paper will discuss the main approaches applied to PUD synthesis in order to meet severe environmental restrictions resulting from the EU legislation.
Omówiono metody syntezy dyspersji wodnych poli(uretanowo-mocznikowych) (PUD), które znajdują coraz szersze zastosowanie, szczególnie w produkcji klejów i powłok. PUD są na ogół produktami bezpiecznymi dla środowiska, ze względu na brak lub małą zawartość lotnych związków organicznych (VOC), co jest ważne w świetle obecnej polityki ochrony środowiska. Przedstawione w pracy metody syntezy PUD uwzględniają wymagania wynikające z prawodawstwa Unii Europejskiej w zakresie spełniania surowych ograniczeń środowiskowych.
Źródło:
Polimery; 2015, 60, 9; 536-540
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wykorzystanie etapowej budowy z przeciążeniem do wzmocnienia podłoża organicznego nasypu drogi ekspresowej
Use of staged construction with preloading for improvement of organic subsoil under expressway embankment
Autorzy:
Lechowicz, Z.
Garbulewski, K.
Bakowski, J.
Wdowska, M.
Wrzesinski, G.
Fernandes, I.R.
Powiązania:
https://bibliotekanauki.pl/articles/40959.pdf
Data publikacji:
2018
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
budownictwo drogowe
drogi ekspresowe
nasypy drogowe
podloza organiczne
wzmacnianie podloza
budowa etapowa z przeciazeniem
drenaz pionowy
geowlokniny
road construction
expressway
road embankment
organic subsoil
subsoil improvement
staged construction
vertical drainage
nonwoven geotextile fabric
Źródło:
Acta Scientiarum Polonorum. Architectura; 2018, 17, 2
1644-0633
Pojawia się w:
Acta Scientiarum Polonorum. Architectura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of biomechanics of skull structures damages caused by dynamic loads
Autorzy:
Ptak, M.
Ratajczak, M.
Kwiatkowski, A.
Sawicki, M.
Wilhelm, J.
Fernandes, F. A. O.
Druszcz, A.
Powiązania:
https://bibliotekanauki.pl/articles/306216.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
czaszka
urazy
biomechanika
FEM
skull fracture
biomechanics
cranial sutures
vulnerable road user
finite element method
Opis:
The aim of the study was to examine the influence of cranial sutures on the crack behaviour of a human skull after the impact. The authors focused on the assessment of skull breaking nature, based on a real-world vehicle-to-bicyclist accident. In the state of the art, there is still no consensus about sutures mechanical properties. Currently, most of the numerical head models do not have distinguished cranial sutures. Methods: The authors compared different elastic properties for cranial sutures and their influence on the nature of the skull fracture. The mathematical and numerical modelling have been applied to mimic the nature of the skull fracture. The LS-DYNA explicit code with material models featuring the erosion of finite elements was used. The models of the skull with different cranial sutures properties were impacted against a validated front-end of a vehicle. Results: Various fracture patterns were obtained for different material properties of the sutures and the results were compared to a model without the cranial sutures. Based on the results, a graph was plotted to indicate differences in sutures energy absorption capabilities. The numerical results were supported by the mathematical modelling. The developed diagram may enable better understanding of the complex mechanical phenomena on the suture interface. Conclusions: Biomechanical evidence was provided for the important role of the sutures in numerical models as well as their significant influence on the biomechanics of skull fractures caused by dynamic loads.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 4; 143-150
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of ISTTOK runaway - electrons energies by means of a Cherenkov - type probe with modified AlN radiators
Autorzy:
Jakubowski, L.
Plyusnin, V. V.
Sadowski, M. J.
Zebrowski, J.
Malinowski, K.
Rabiński, M.
Fernandes, H.
Silva, C.
Duarte, P.
Jakubowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/147516.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ISTTOK
runaway electrons
Cherenkov detector
AlN radiators
Opis:
Measurements of fast electrons, as performed during recent few years in small tokamaks, demonstrated that detectors based on the Cherenkov effect are very useful tools for such studies. The modernized measuring heads, which were equipped with miniature aluminum-nitride (AlN) radiators, enabled to determine locations and instants of the fast electrons emission and to estimate their energy. A comparison of four measuring channels showed that in ISTTOK the most important role was played by electrons of energy less than 90 keV.
Źródło:
Nukleonika; 2012, 57, 2; 177-181
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new plesiosaur from the Lower Jurassic of Portugal and the early radiation of Plesiosauroidea
Autorzy:
Puertolas-Pascual, E.
Marx, M.
Mateus, O.
Saleiro, O.
Fernandes, A.E.
Marinheiro, J.O.
Tomas, C.
Mateus, S.
Powiązania:
https://bibliotekanauki.pl/articles/2082325.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Plesiosauria
radiation
Sinemurian
Jurassic
Iberian Peninsula
Europe
Opis:
A new plesiosaur partial skeleton, comprising most of the trunk and including axial, limb, and girdle bones, was collected in the lower Sinemurian (Coimbra Formation) of Praia da Concha, near São Pedro de Moel in central west Portugal. The specimen represents a new genus and species, Plesiopharos moelensis gen. et sp. nov. Phylogenetic analysis places this taxon at the base of Plesiosauroidea. Its position is based on this exclusive combination of characters: presence of a straight preaxial margin of the radius; transverse processes of mid-dorsal vertebrae horizontally oriented; ilium with sub-circular cross section of the shaft and subequal anteroposterior expansion of the dorsal blade; straight proximal end of the humerus; and ventral surface of the humerus with an anteroposteriorly long shallow groove between the epipodial facets. In addition, the new taxon has the following autapomorphies: iliac blade with less expanded, rounded and convex anterior flank; highly developed ischial facet of the ilium; apex of the neural spine of the first pectoral vertebra inclined posterodorsally with a small rounded tip. This taxon represents the most complete and the oldest plesiosaur species in the Iberian Peninsula. It is also the most complete, best preserved, and oldest marine vertebrate in the region and testifies to the incursion of marine reptiles in the newly formed proto-Atlantic sea, prior to the Atlantic Ocean floor spreading in the Early Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2021, 66, 2; 369-388
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation and analysis of an isolated full-bridge DC/DC boost converter operating with a modified perturb and observe maximum power point tracking algorithm
Autorzy:
Matias, C. A.
Medeiros, G. P.
Moraes, P. H. F.
Fernandes, B. de A.
Alves, A. J.
Calixto, W. P.
Furriel, G. P.
Powiązania:
https://bibliotekanauki.pl/articles/136247.pdf
Data publikacji:
2017
Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Tematy:
energy efficiency
geometric Brownian motion
Monte Carlo simulation
Opis:
The purpose of the present study is to simulate and analyze an isolated full-bridge DC/DC boost converter, for photovoltaic panels, running a modified perturb and observe maximum power point tracking method. The zero voltage switching technique was used in order to minimize the losses of the converter for a wide range of solar operation. The efficiency of the power transfer is higher than 90% for large solar operating points. The panel enhancement due to the maximum power point tracking algorithm is 5.06%.
Źródło:
Transactions on Environment and Electrical Engineering; 2017, 2, 2; 45-50
2450-5730
Pojawia się w:
Transactions on Environment and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-14 z 14

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