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


Tytuł:
On the Faddeev-Sominsky’s algorithm
Autorzy:
Torres-Silva, H.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1166341.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Adjoint matrix
Characteristic equation
Eigenvalue problem
Faddeev-Sominsky’s method
Inverse matrix
Leverrier-Takeno’s algorithm
Resolvent of a matrix
Opis:
We comment that the Faddeev-Sominsky’s process to obtain an inverse matrix is equivalent to the Cayley-Hamilton-Frobenius theorem plus the Leverrier-Takeno’s method to construct the characteristic polynomial of an arbitrary matrix. Besides, we deduce the Lanczos expression for the resolvent of the corresponding matrix.
Źródło:
World Scientific News; 2018, 106; 238-244
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vector field in the reciprocal space
Autorzy:
Torres-Silva, H.
Barrera-Figueroa, V.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177958.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Reciprocal Space
Spatial Fourier transformation
Transverse and longitudinal δ-function
Opis:
As a preparation for the study of Maxwell equations under a spatial Fourier transform, we analyze properties of the transverse and longitudinal components of an arbitrary vector field in the reciprocal space.
Źródło:
World Scientific News; 2018, 97; 278-284
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Experimental Approach to Vibro-Acoustic Study of Beam-Type Structures
Autorzy:
Torres-Romero, J.
Cardenas, W.
Carbajo, J.
Segovia Eulogio, E. G.
Ramis-Soriano, J.
Powiązania:
https://bibliotekanauki.pl/articles/178014.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
beam
modal shape
modal analysis
MLS
Maximum Length Sequence
bending wave propagation velocity
Opis:
In this paper an alternative procedure to vibro-acoustics study of beam-type structures is presented. With this procedure, it is possible to determine the resonant modes, the bending wave propagation velocity through the study of the radiated acoustic field and their temporal evolution in the frequency range selected. As regards the purely experimental aspect, it is worth noting that the exciter device is an actuator similar to is the one employed in distributed modes loudspeakers; the test signal used is a pseudo random sequence, in particular, an MLS (Maximum Length Sequence), facilitates post processing. The study case was applied to two beam-type structures made of a sandstone material called Bateig. The experimental results of the modal response and the bending propagation velocity are compared with well-established analytical solution: Euler-Bernoulli and Timoshenko models, and numerical models: Finite Element Method – FEM, showing a good agreement.
Źródło:
Archives of Acoustics; 2018, 43, 2; 283-295
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Guitars and Violins Made using Alternative Woods through Mobility Measurements
Autorzy:
Torres, J. A.
Torres-Martínez, R.
Powiązania:
https://bibliotekanauki.pl/articles/176571.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mobility
violin
guitar
luthier
Stradivari
Opis:
The feasibility of substituting the types of wood usually employed in the making of guitars and violins was analyzed, but without comparing the properties of involved materials as it is often reported; in this work, the vibrational behavior of twelve guitars and three violins built with alternative types of woods was compared to data of classical instruments available in the literature. In the guitars here measured, the back plate and ribs were not made from traditional woods; while in the violins, only the top plate was made from an alternative type of wood. The results showed that changing the wood of back plate and ribs does not radically affect the typical mobility of a guitar; however, the expected mobility for a violin was not clearly obtained substituting the wood of the top plate. Thus it seems feasible to substitute the wood of back plate and ribs in guitars without causing dramatic changes in their performance; in contrast, a change of the wood type for top plate in violins seems inadvisable unless the design of the top plate is modified to compensate the differences between the woods.
Źródło:
Archives of Acoustics; 2015, 40, 3; 351-358
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Terahertz Detection of Quantum Cascade Laser Emission by Plasma Waves in Field Effect Transistors
Autorzy:
Teppe, F.
Consejo, C.
Torres, J.
Chenaud, B.
Solignac, P.
Fathololoumi, S.
Wasilewski, Z.
Zholudev, M.
Dyakonova, N.
Coquillat, D.
El Fatimy, A.
Buzatu, P.
Chaubet, C.
Knap, W.
Powiązania:
https://bibliotekanauki.pl/articles/1492959.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.30.Tv
07.57.Kp
52.35.-g
Opis:
We report on the resonant detection of a 3.1 THz radiation produced by a quantum cascade laser using a 250 nm gate length GaAs/AlGaAs field effect transistor at liquid nitrogen temperature. We show that the physical mechanism of the detection is related to the plasma waves excited in the transistor channel. The detection is enhanced by increasing the drain current and driving the transistor into saturation regime. These results clearly show that plasma wave nanometer-size transistors can be used as detectors in all-solid-state terahertz systems where quantum cascade lasers act as sources.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 930-932
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Small-Signal Characterization of FET/HEMT for Terahertz Applications
Autorzy:
Starikov, E.
Shiktorov, P.
Gružinskis, V.
Marinchio, H.
Nouvel, P.
Torres, J.
Palermo, C.
Chusseau, L.
Varani, L.
Ziadé, P.
Powiązania:
https://bibliotekanauki.pl/articles/1505675.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Ht
72.30.+q
Opis:
Calculations of the small-signal response of InGaAs HEMTs by using the hydrodynamic approach coupled with a pseudo-2D Poisson equation are performed. The spectra of small-signal admittance and impedance are found to demonstrate series of the resonant peaks corresponding to excitation of plasma waves. Possibilities and conditions of instability onset and THz signal detection are discussed.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 203-205
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-dimensional Newtons problem of minimal resistance
Autorzy:
Silva, C. J.
Torres, D. F.
Powiązania:
https://bibliotekanauki.pl/articles/969988.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
Newton's problem of minimal resistance
dimension two
calculus of variations
optimal control
Opis:
Newton's problem of minimal resistance is one of the first problems of optimal control: it was proposed, and its solution given, by Isaac Newton in his masterful Principia Mathematica, in 1686. The problem consists of determining, in dimension three, the shape of an axis-symmetric body, with assigned radius and height, which offers minimum resistance when it is moving in a resistant medium. The problem has a very rich history and is well documented in the literature. Of course, at a first glance, one suspects that the two dimensional case should be well known. Nevertheless, we have looked into numerous references and asked at least as many experts on the problem, and we have not been able to identify a single source. Solution was always plausible to everyone who thought about the problem, and writing it down was always thought not to be worthwhile. Here we show that this is not the case: the two-dimensional problem is richer than the classical one, being, in some sense, more interesting. Novelties include: (i) while in the classical three-dimensional problem only the restricted case makes sense (without restriction on the monotonicity of admissible functions the problem does not admit a local minimum), we prove that in dimension two the unrestricted problem is also well-posed when the ratio of height versus radius of base is greater than a given quantity; (ii) while in three dimensions the (restricted) problem has a unique solution, we show that in the restricted two-dimensional problem the minimizer is not always unique - when the height of the body is less or equal than its base radius, there exists infinitely many minimizing functions.
Źródło:
Control and Cybernetics; 2006, 35, 4; 965-975
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New sauropod trackways from the Middle Jurassic of Portugal
Autorzy:
Santos, V F
Moratalla, J.J.
Royo-Torres, R.
Powiązania:
https://bibliotekanauki.pl/articles/22749.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new sauropod
sauropod
paleontology
trackway
Middle Jurassic
Jurassic
Portugal
Dinosauria
Sauropoda
morphotype
Opis:
The Galinha tracksite reveals a sequence of Bajocian–Bathonian limestones belonging to the Serra de Aire Formation (West−Central Portugal) and is one of the few sites in the world where Middle Jurassic sauropod dinosaur tracks can be found. This tracksite is characterised by the presence of long, wide gauge sauropod trackways, the Middle Jurassic age of which suggests these dinosaurs were more widely distributed over time than previously thought. Two trackways contain unique pes and manus prints with morphologies that allow a new sauropod ichnotaxon to be described: Polyonyx gomesi igen. et isp. nov. On the basis of different manus/pes prints and trackway features, the proposal is made to subdivide Sauropodomorpha ichno−morphotypes into five groups: Tetrasauropus−like, Otozoum−like, Breviparopus/Parabrontopodus−like; Brontopodus−like, and Polyonyx−like. Polyonyx gomesi igen. et isp. nov. is thought to represent a nonneosauropod eusauropod, with a well developed manus digit I. The posterior orientation of this digit print suggests they were made by a eusauropod dinosaur with a posteriorly rotated pollex. The manus print morphologies observed in two trackways suggest a stage of manus structure intermediate between the primitive non−tubular sauropod manus and the tubular metacarpal arrangement characteristic of more derived sauropods. The low heteropody (manus:pes area ratio 1:2) of the trackway renders it possible they could have been made by eusauropods such as Turiasaurus riodevensis, which has a similar manus:pes area ratio. The Polyonyx igen. nov. trackway was made by non−neosauropod eusauropod, and suggests that wide gauge sauropod trackways were not exclusively made by Titanosauriformes.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 3; 409-422
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predicting motor oil condition using artificial neural networks and principal component analysis
Prognozowanie stanu oleju silnikowego za pomocą sztucznych sieci neuronowych i analizy składowych głównych
Autorzy:
Rodrigues, Joao
Costa, Ines
Farinha, J. Torres
Mendes, Mateus
Margalho, Luis
Powiązania:
https://bibliotekanauki.pl/articles/1841873.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
condition monitoring
oil analysis
multivariate analysis
predictive maintenance
monitorowanie stanu
analiza oleju
analiza wielowymiarowa
konserwacja predykcyjna
Opis:
The safety and performance of engines such as Diesel, gas or even wind turbines depends on the quality and condition of the lubricant oil. Assessment of engine oil condition is done based on more than twenty variables that have, individually, variations that depend on the engines’ behaviour, type and other factors. The present paper describes a model to automatically classify the oil condition, using Artificial Neural Networks and Principal Component Analysis. The study was done using data obtained from two passenger bus companies in a country of Southern Europe. The results show the importance of each variable monitored for determining the ideal time to change oil. In many cases, it may be possible to enlarge intervals between maintenance interventions, while in other cases the oil passed the ideal change point.
Bezpieczeństwo i wydajność silników takich, jak silniki Diesla czy gazowe, a nawet turbiny wiatrowe, zależą od jakości i stanu oleju smarowego. Stanu oleju silnikowego ocenia się na podstawie ponad dwudziestu zmiennych, z których każda ulega wahaniom w zależności od typu i zachowania silnika oraz innych czynników. W niniejszym artykule opisano model, który pozwala na automatyczną klasyfikację stanu oleju, z wykorzystaniem sztucznych sieci neuronowych i analizy składowych głównych. Badania przeprowadzono na podstawie danych uzyskanych od dwóch przewoźników pasażerskich działających na terenie jednego z krajów położonych na południu Europy. Wyniki pokazują, że każda z monitorowanych zmiennych ma znaczenie dla określenia idealnego czasu na wymianę oleju. Podczas gdy w wielu przypadkach w badanych przedsiębiorstwach możliwe było zwiększenie odstępów czasowych między działaniami konserwacyjnymi, w innych, idealny moment wymiany oleju został przekroczony.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 3; 440-448
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Airborne pollen of Carya, Celtis, Cupressus, Fraxinus and Pinus in the metropolitan area of Monterrey Nuevo Leon, Mexico
Autorzy:
Rocha-Estrada, A
Alvarado-Vazquez, M.A.
Torres-Cepeda, T.E.
Foroughbakhch-Pournavab, R.
Hernandez-Pinero, J.L.
Powiązania:
https://bibliotekanauki.pl/articles/51592.pdf
Data publikacji:
2008
Wydawca:
Instytut Medycyny Wsi
Tematy:
Pinus
pollen grain
Celtis
metropolitan area
airborne pollen
Carya
street
private garden
public park
Mexico
Nuevo Leon
plant
atmosphere
Monterrey
garden
Cupressus
Fraxinus
Źródło:
Annals of Agricultural and Environmental Medicine; 2008, 15, 2
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using visual and force information in robot-robot cooperation to build metallic structures
Autorzy:
Pomares, J.
Gil, P.
Corrales, J. A.
Garcia, G. J.
Puente, S. T.
Torres, F.
Powiązania:
https://bibliotekanauki.pl/articles/384655.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Opis:
In this paper, a cooperative robot-robot approach to construct metallic structures is presented. In order to develop this task, a visual-force control system is proposed. The visual information is composed of an eye-in-hand camera, and a time of flight 3D camera. Both robots are equipped by a force sensor at the end-effector. In order to allow a human cooperate with both robots, an inertial motion capture system and an indoor localization system are em ployed. This multisensorial approach allows the robots to cooperatively construct the metallic structure in a flexible way and sharing the workspace with a human operator.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 3; 96-101
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
THz Emission Induced by an Optical Beating in Nanometer-Length High-Electron-Mobility Transistors
Autorzy:
Nouvel, P.
Torres, J.
Marinchio, H.
Laurent, T.
Palermo, C.
Varani, L.
Teppe, F.
Shiktorov, P.
Starikov, E.
Gruzinskis, V.
Powiązania:
https://bibliotekanauki.pl/articles/1505652.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Nj
72.20.Ht
72.30.+q
Opis:
Experimental results of direct measurement of resonant terahertz emission optically excited in InGaAs HEMT channels are presented. The emission was attributed to two-dimensional plasma waves excited by photogeneration of electron-hole pairs in the HEMT channel at the frequency of the beating of two cw-laser sources. The presence of resonances for the radiation emission in the range of $f_0$ ± 10 GHz (with $f_0$ from 0.3 up to 0.5 THz) detected by a Si-bolometer is found. The intensity of THz emission exhibits a nonlinear growth with increase of the pumping power.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 199-202
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnesium biodegradable implants coated with polylactic acid
Autorzy:
Munoz, M.
Rams, J.
Lopez, A.
Matykina, E.
Torres, B.
Powiązania:
https://bibliotekanauki.pl/articles/284077.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
implants
biodegradation
magnesium alloys
Źródło:
Engineering of Biomaterials; 2017, 20, no. 143 spec. iss.; 28
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solar generation estimation in electric power systems for prospective frequency control studies
Autorzy:
Martínez-García, A. A.
Torres-Breffe, O. E.
Vilaragut-Llanes, M.
Delgado-Fernandez, O.
Szpytko, J.
Salgado-Duarte, Y.
Powiązania:
https://bibliotekanauki.pl/articles/2172499.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
green shipping
solar power
electric power systems
energy storage systems
photovoltaic power generation
cuban electrical system
energy sources
photo voltage solar generation
Opis:
Increasing the presence of non-conventional clean energy sources in Electrical Power Systems (EPS) is a global strategic goal. Particularly, photovoltaic systems are attractive due to their versatility, low maintenance cost, easy installation, noiselessness, etc. However, the integration of photovoltaic systems into EPS increases the necessary regulation actions performed by system generators due to stochastic fluctuations of solar radiation, especially on cloudy days. Even using complex models that consider many variables, solar irradiation and its corresponding photovoltaic power generation are difficult variables to forecast with accuracy in cloudy day scenarios. To address this problem, Energy Storage Systems (BESS) have been proposed as a solution to mitigate the variability of photovoltaic generation, which reduce the need to use traditional spinning reserves and provide auxiliary grid services. The BESS selection required to mitigate photovoltaic generation is directly related to the worst-case daily variability of photovoltaic generation in the short term. This paper proposes a practical estimation of daily perspective photo voltage solar generation curve in Electrical Power Systems.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2022, 16, 2; 211--217
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plasma Oscillations in Nanotransistors: Application to THz Radiations Detection and Generation
Autorzy:
Marinchio, H.
Sabatini, G.
Palermo, C.
Nouvel, P.
Torres, J.
Varani, L.
Shiktorov, P.
Starikov, E.
Gružinskis, V.
Powiązania:
https://bibliotekanauki.pl/articles/1505457.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Nj
72.20.Ht
72.30.+q
Opis:
By means of a numerical hydrodynamic model, we consider the mechanism of collective plasma oscillations in a field-effect transistor channel under different excitations and biasing conditions. First, we consider the case of a device externally-excited by a harmonic optical beating or an electronic excitation under constant current condition at the drain. Both situations exhibit sharp resonances related to the first odd plasma modes illustrating the possibility of using the HEMT as a terahertz photomixer or detector. Then, we demonstrate that the frequencies, amplitudes and quality factors of the resonances can be strongly modified by varying the drain biasing condition from current- to voltage-driven operation.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 103-106
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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