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Tytuł:
Research on hybrid topology of single-switch ICPT for battery charging
Autorzy:
Zhang, Guangzong
Wang, Chunfang
Zheng, Jianfen
Li, Houji
Powiązania:
https://bibliotekanauki.pl/articles/949898.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
constant current
constant voltage
higher harmonics
ICPT
single-switch
inverter
Opis:
In order to realize constant current and constant voltage charging for batteries by inductively coupled power transfer (ICPT) technology, a single-switch CL/LCL circuit is designed. The single-switch CL/LCL circuit is composed of a CL/LCL compensation network and single-switch inverter. The proposed circuit is compared with the traditional constant current and constant voltage circuit in the structure. The operating process of the single-switch CL/LCL circuit and the principle to realize a zero-voltage switch (ZVS) are analysed in detail in this paper. The voltage gain and current gain of the circuit are calculated, which demonstrates that the circuit is able to suppress higher harmonics strongly. By using Fourier decomposition, the voltage on the primary-side compensation capacitor can be obtained. After constructing the equivalent mutual inductance model of the circuit, the formulas and parameters are deduced and calculated. Finally, an experiment platform is built to verify the proposed circuit can realize constant current and constant voltage.
Źródło:
Archives of Electrical Engineering; 2020, 69, 4; 841-855
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Balancing vectors and convex bodies
Autorzy:
Banaszczyk, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/1292627.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
balancing vectors
Steinitz constant
Opis:
Let U, V be two symmetric convex bodies in $ℝ^n$ and |U|, |V| their n-dimensional volumes. It is proved that there exist vectors $u_1,...,u_n ∈ U$ such that, for each choice of signs $ε_1,...,ε_n = ± 1$, one has $ε_1 u_1 + ... + ε_n u_n ∉ rV$ where $r = (2πe^2)^{-1/2} n^{1/2}(|U|/|V|)^{1/n}$. Hence it is deduced that if a metrizable locally convex space is not nuclear, then it contains a null sequence $(u_n)$ such that the series $∑_{n = 1}^∞ ε_n u_{π(n)}$ is divergent for any choice of signs $ε_n = ± 1$ and any permutation π of indices.
Źródło:
Studia Mathematica; 1993, 106, 1; 93-100
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of frequency-controlled induction motor at higher than rated frequencies and a constant stator voltage
Autorzy:
Firago, B.
Powiązania:
https://bibliotekanauki.pl/articles/1813847.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
induction motor
frequency control
constant load torque
constant load power
rating power
Opis:
A technique for calculation of characteristics of an induction motor operating under conditions: the constant load torque or constant load power at frequencies higher than rated ones and the rated stator voltage is presented. For the mode of constant load power the analytical solution of frequency-controlled induction motor electric drive transients is obtained.
Źródło:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały; 2013, 69, 33; 30--43
1733-0718
Pojawia się w:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertical Fall of a Body Under Free Motion
Autorzy:
Pluta, Z.
Hryniewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/411583.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
material body
kinetics
free fall
Path/way length
velocity
acceleration
Inertia acceleration
Gravitation acceleration
time constant
Way constant
Gravitation number constant
Opis:
The paper aims at the kinetics of a body under free fall, especially free body motion, the motion occurring in the Earth environs space, that is in the range of the gravity action. A new adequate theory of such a motion, opening new not known kinetic magnitudes, has been elaborated. This theory has its source, which is the dependence of the way length on time. That is the way characteristics created in this work. The worked out theory has been verified by experiment, referred to two different realities. One of them was the body motion in the air environment of the Earth environs space, with the second one occurring in a determined machining space-time. The adequate earth acceleration/gravity has been calculated taking advantage of the theory elaborated; and its value, as indicated, is equal 3.85 mźs-2. Two kinds of accelerations have been separated: inertial and gravitational. The relations occurring between their values on the neighbouring potential fields, unstable, and stable, have been discovered. That discovery indicates on the existence of quantum nature of gravitation.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 4; 56-72
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The eigenvalue problem with conductivity boundary conditions
Autorzy:
Bucur, D.
Durus, I.
Oudet, E.
Powiązania:
https://bibliotekanauki.pl/articles/970293.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
eigenvalues
isoperimetric
constant boundary conditions
Opis:
In this paper we study isoperimetric inequalities for the eigenvalues of the Laplace operator with constant and locally constant boundary conditions. Existence and stability results are presented in the of the gamma and weak gamma convergencies, together with identification of optimal sets by analytical and numerical methods.
Źródło:
Control and Cybernetics; 2008, 37, 4; 811-829
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric studies of nano structured BaTi1-xSnxO3 solid solutions
Autorzy:
Bitra, H. Ch. R.
Prasad, B. B. V. S. V.
Powiązania:
https://bibliotekanauki.pl/articles/412300.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
BTSx
XRD
SEM
dielectric constant
Opis:
BaTi1-xSnxO3 (BTSx) ceramics had been prepared by temperature sintering technique. Initially, the samples were calcined at a temperature at 900 °C for 2 hours, after that ball milling was done and then the samples were sintered at a temperature of 1150 °C for 3 hours. X-ray diffractometry, Scanning Electron Microscopy, Energy Dispersive Spectroscopy and Dielectric measurements were carried out and structural, micro structural and elemental analyses were discussed in brief.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 13, 2; 191-201
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Packing in Orlicz sequence spaces
Autorzy:
Rao, M. M.
Ren, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1218867.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
packing constant
quantitative index
interpolation
Opis:
We show how one can, in a unified way, calculate the Kottman and the packing constants of the Orlicz sequence space defined by an N-function, equipped with either the gauge or Orlicz norms. The values of these constants for a class of reflexive Orlicz sequence spaces are found, using a quantitative index of N-functions and some interpolation theorems. The exposition is essentially selfcontained.
Źródło:
Studia Mathematica; 1997, 126, 3; 235-251
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Możliwość zastosowania odczynnika Fentona w procesach usuwania formaldehydu ze ścieków pochodzących z przemysłu drzewnego
Application of Fenton reagent in the process of formaldehyde removal from the timber industry wastewater
Autorzy:
Dębowski, M.
Zieliński, M.
Dudek, M.
Grala, A.
Powiązania:
https://bibliotekanauki.pl/articles/1819294.pdf
Data publikacji:
2012
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
degradation
Fenton's reagent
constant magnetic field
Opis:
The aim of this study was to determine the possibility of degradation of formaldehyde in the effluents from the timber industry with Fenton's reagent. Effluent from the timber industry are characterized by a high concentration of organic compounds and formaldehyde as an obstacle to the purification of wastewater using microorganisms and therefore an alternative to biological methods is the use of solutions based on chemical methods. In recent years, considerable attention is given to testing and implementation of the so-called advanced oxidation methods (Advanced Oxidation Processes - AOPs). A common feature of these systems is that they allow the generation of highly reactive hydroxyl radicals OH center dot with 2,8 V oxidation potential, which react with almost all organic compounds. Fast-paced distribution of impurities, versatility and high efficiency make advanced oxidation methods are now increasingly considered as a promising alternative compared to conventional methods, techniques, wastewater and sludge treatment Wastewater used in the study came from the wood of an industrial plant where the business is the manufacture of chipboard. The study was conducted in three phases with different type of chemical reactants introduced into the technological system. In the first stage reactor was dosed only iron ions Fe3+, H2O2 in the second stage, while the third part of an experiment to test the Fenton reagent treatment was introduced Fe3+ /H2O2. Each stage is divided into five variants. The criterion for division of the variants was the dose of chemical reagents. The study confirmed the applicability of advanced oxidation technologies based on Fenton's reagent in the process of degradation of formaldehyde. It was found that the efficiency of removal of contaminants from wastewater was directly connected with the dose of chemical reagents introduced into the technological system. It was also noted that increasing the dose above the Fenton reagent Fe3+ 0,3 g /l and 3,0 g H2O2/l does not significantly affect the final results of the purification process. The highest results were obtained in the technology used in doses of 0,3 g Fe 3+/l and 3,0 g H2O2 /l to 0,6 g Fe3+/l and 6,0 g H2O2/l. Limiting values of COD in the experimental variants was approximately 70,0% while the concentration of formaldehyde close to 60,0%. If dispensing the water only Fe3+ ions obtained the highest efficiency and reduce the COD concentration of formaldehyde was 28,3% sequentially and 14,5%. The final concentrations of the analyzed indicators of pollution, if only H2O2 dosing were similar to their concentrations in raw wastewater.
Źródło:
Rocznik Ochrona Środowiska; 2012, Tom 14; 587-596
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability Design of Complex Systems by Minimizing the Lifetime Variance
Autorzy:
Łobos, E.
Momot, M.
Powiązania:
https://bibliotekanauki.pl/articles/908509.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
matematyka
reliability
constant failure rate
redundancy
Opis:
The problem considered in this paper is the minimization of the lifetime variance of a complex system subject to its expected life and economic constraints. The example of a bridge network, in which all elements have constant failure rates, illustrates the problem. A numerical algorithm for solving this optimization problem by using exact formulae for system lifetime moments is included. Using this algorithm, we can obtain results better than the solutions known from earlier papers.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 4; 553-557
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of dynamic properties of flat plate and heat pipe solar collectors
Autorzy:
Obstawski, P.
Bakoń, T.
Tulej, M.
Powiązania:
https://bibliotekanauki.pl/articles/114238.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
solar collector
step response
time constant
Opis:
The paper presents an analysis of dynamic properties of two flat plate solar collectors differing in the design of coil and vacuum tube liquid-vapour (heat-pipe) collector. The collector identification experiment was carried out under field conditions based on the methodology described in PN-EN ISO 9806: 2014-2 standard. The results of the field experiment were compared with those obtained under laboratory conditions.
Źródło:
Measurement Automation Monitoring; 2016, 62, 3; 105-108
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interaction of anthracene and its oxidative derivatives with human serum albumin
Autorzy:
Skupińska, Katarzyna
Zylm, Monika
Misiewicz, Irena
Kasprzycka-Guttman, Teresa
Powiązania:
https://bibliotekanauki.pl/articles/1041275.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
albumin
affinity constant
polycyclic aromatic hydrocarbons
Opis:
Binding affinities of ten polycyclic aromatic hydrocarbons to albumin were determined: anthracene, its eight oxy-derivatives: anthraquinone, 9-anthracenemethanol, 9-anthraldehyde, 9-anthracenecarboxylic acid, 1,4-dihydroxyanthraquinone, 1,5-dihydroxyanthraquinone, 1,8-dihydroxyanthraquinone, 2,6-dihydroxyanthraquinone and benzo[a]pyrene. The quenching of albumin fluorescence was used to measure the PAH - protein interaction. The theoretical curve of calculated fluorescence was fitted to experimental data after necessary corrections regarding PAHs fluorescence and inner filter effect. From the numerical fitting the final association constants were calculated. Anthracene and anthraquinone failed to quench the albumin fluorescence. 9-anthracenecarboxylic acid showed the highest, while 9-anthracenemethanol the weakest albumin binding affinity. The affinity constants determined for 9-anthraldehyde and benzo[a]pyrene were of the same magnitude and indicated low-affinity binding to albumin. The constants obtained for the four dihydroxyanthraquinones were higher, but dissimilar, which suggests that the position of the functional group in anthracene molecule influences the binding constant. Moreover, this study suggests that the type of substituent plays a significant role in PAH-albumin complex formation. The carboxylic group increases the binding affinity of the anthracene molecule the most rather than the presence of both carbonyl and hydroxyl groups. The lowest affinity constants were obtained for aldehyde, methyl and carbonyl substituents.
Źródło:
Acta Biochimica Polonica; 2006, 53, 1; 101-112
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The exact values of nonsquare constants for a class of Orlicz spaces
Autorzy:
Wang, J.
Powiązania:
https://bibliotekanauki.pl/articles/255189.pdf
Data publikacji:
2005
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
nonsquare constant
Orlicz space
PhiDelta-condition
Opis:
We extend the MDelta-condition from [10] and introduce the PhiDelta-condition at zero. Next we discuss nonsquare constant in Orlicz spaces generated by an N-function Phi(u) which satisfy PhiDelta-condition. We obtain exact value of nonsquare constant in this class of Orlicz spaces equipped with the Luxemburg norm.
Źródło:
Opuscula Mathematica; 2005, 25, 2; 325-332
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examining the impact of positive and negative constant learning on the evolution rate
Autorzy:
Gajer, M.
Powiązania:
https://bibliotekanauki.pl/articles/1943200.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska
Tematy:
evolutionary systems
learning process
constant learning
Opis:
The paper discusses the influence of learning on evolutionary processes. In biological sciences it is a well-known fact that the rate of evolution can be effected by learning and the same phenomena can also be observed in artificial evolutionary systems, however, their nature is still not sufficiently well understood. In the paper the influence of constant learning on the rate of evolution is examined. The constant learning is a kind of learning during which the genotype of the individual being taught is moved toward the global optimum over a constant value. If the fitness function is monotonic, it can be concluded from the mathematical theory that such kind of learning should decelerate evolution. However, this fact is highly counterintuitive and for this reason it should be proved by numerical experiments. In the article the results of numerical simulations are presented. They prove that evolution is indeed decelerated by learning in case of the sigmoid fitness function. Moreover, two cases of constant learning were examined in the paper. These are the positive and negative constant learning. It was demonstrated that in the case of the negative constant learning the evolution was decelerated to a larger extent than in the case of the positive constant learning. The obtained results can help explain certain phenomena concerning the impact of learning on the evolution both in natural and artificial evolutionary systems.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2009, 13, 4; 355-362
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficiency evaluation of Luffa cylindrica and Mucuna sloanei seeds in dye removal: A news approach
Autorzy:
Nnaji, P. C.
Okoye, C. C.
Umeuzuegbu, J. U.
Powiązania:
https://bibliotekanauki.pl/articles/1031647.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Luffa cylindrica
Mucuna sloanei
coag-flocculation rate constant
critical coag-flocculation rate constant
dye-based wastewater
Opis:
The use of Luffa cylindrica (LC) and Mucuna sloanei (MS) seeds as coagulants in the removal of dye by coag-flocculation was evaluated using a new approach. The approach uses the coag-flocculation rate constant K11, calculated using experimental data obtained while using LC and MS as coagulants in coag-flocculation process as a valid indicator to determine the optimum condition. The research also applied criterion for critical coag-flocculation rate constant Kc to satisfy World Health Organization’s minimum allowable level of suspended substance for wastewater discharge. In the criterion K11 ≥ Kc indicates better performance. The results indicated that K11 of 0.00214 L/mg·min for LC and 0.00208 L/mg·min for MS surpassed 0.00016 L/mg·min Kc value. This was observed for LC and MS at pH 2, but 1400 mg/L and 1200 mg/L, respectively. From the above, in accordance with the WHO guideline, the dosage of both coagulants meets the requirement. The solution pH could not meet the standard. Nonetheless, MS satisfied the requirement at pH 6, for dosage and pH. These results correspond to what was obtained experimentally. Therefore, in coag-flocculation kinetic modeling, this novel approach can be considered to track the efficiency of these sensitive factors in water treatment plants to meet the effluent quality requirements.
Źródło:
World Scientific News; 2020, 146; 184-201
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-dimensional real symmetric spaces with maximal projection constant
Autorzy:
Chalmers, Bruce
Lewicki, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1208018.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
absolute projection constant
minimal projection
symmetric spaces
Opis:
Let V be a two-dimensional real symmetric space with unit ball having 8n extreme points. Let λ(V) denote the absolute projection constant of V. We show that $λ(V) ≤ λ(V_n)$ where $V_n$ is the space whose ball is a regular 8n-polygon. Also we reprove a result of [1] and [5] which states that $4/π = λ(l₂^{(2)}) ≥ λ(V)$ for any two-dimensional real symmetric space V.
Źródło:
Annales Polonici Mathematici; 2000, 73, 2; 119-134
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Constant-sign solutions for a nonlinear Neumann problem involving the discrete p-Laplacian
Autorzy:
Candito, P.
D'Agui, G.
Powiązania:
https://bibliotekanauki.pl/articles/255253.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
constant-sign solution
difference equations
Neumann problem
Opis:
In this paper, we investigate the existence of constant-sign solutions for a nonlinear Neumann boundary value problem involving the discrete p-Laplacian. Our approach is based on an abstract local minimum theorem and truncation techniques.
Źródło:
Opuscula Mathematica; 2014, 34, 4; 683-690
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Best constant approximants in Orlicz-Lorentz spaces
Autorzy:
Levis, F. E.
Cuenya, H. H.
Priori, A. N.
Powiązania:
https://bibliotekanauki.pl/articles/746619.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
best constant approximants
Orlicz-Lorentz spaces
monotonicity
Opis:
The best constant approximant operator is extended from an Orlicz-Lorentz space \(\Lambda_{w,\varphi}\) to the space \(\Lambda_{w,\varphi'}\), where \(\varphi'\) is the derivative of \(\varphi\). Monotonicity property of its extension is established.
Źródło:
Commentationes Mathematicae; 2008, 48, 1
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative FE-studies of interface behavior of granular Cosserat materials under constant pressure and constant volume conditions
Autorzy:
Ebrahimian, B.
Alsaleh, M. I.
Kahbasi, A.
Powiązania:
https://bibliotekanauki.pl/articles/38629565.pdf
Data publikacji:
2021
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
interface shearing
wall roughness
constant pressure
constant volume
dilatancy constraint
Cosserat FE model
discrete element method (DEM)
Opis:
This article shows the outcomes of a systematic series of finite element (FE) calculations relevant to the shear behavior of a particulate-continuum interface system under different normal boundary conditions. In this respect, shearing of a thin and long granular Cosserat layer in the vicinity of a rigid moving wall with varied surface roughness values is analyzed under constant normal pressure and constant volume conditions. The material behavior is defined with a special elasto-plastic Cosserat model, taking into account micro-rotation, micro-curvature, couple stress, and mean particle size. The interaction between the layer of boundary particles and the surface roughness of the adjoining bottom wall is modeled by the rotation resistance of particles along the wall surface. Herein, the coupled effects of normal confining constraints imposed on the layer and the surface roughness of the bottom wall, are considered on the response of granular material under shearing. The influences of pressure level and initial void ratio are explored as well. Numerical results demonstrate that the dilatancy constraint prescribed to the interface plane in the normal direction, and the wall roughness have visible influences on the interface shear resistance as well as the deformation field formed within the layer. After large shearing, the width of the localized zone along the wall does not necessarily depend on the normal confining constraint and the applied pressure level. However, the localized zone characteristics and the interface shear response are mainly affected by the initial void ratio of the material. In addition to FE analyses, DEM-based simulations are also performed to investigate the micro-mechanical response of granular medium adjacent to a wall under shearing. FE predictions are qualitatively compared with DEM results, and reasonable agreement is observed.
Źródło:
Archives of Mechanics; 2021, 73, 5-6; 421-470
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shifted Chebyshev-Lanczos polynomials
Autorzy:
Caltenco, J. H.
López-Bonilla, J.
Peña-Rivero, R.
Powiązania:
https://bibliotekanauki.pl/articles/1177824.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Feigenbaum constant
Modified Lanczos polynomials
Pascal triangle
Opis:
We show an algorithm for to express in terms of the modified Chebyshev-Lanczos polynomials , which is important to reduce the degree of a polynomial in the interval [0, 1]. Besides, with the use of into logistic map we obtain a simple geometric interpretation of the Feigenbaum´s universal constant.
Źródło:
World Scientific News; 2018, 99; 222-226
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Die profile optimization for forging constant velocity joint casings
Optymalizacja profili matryc do kucia obudowy przegubów homokinetycznych
Autorzy:
Gronostajski, Z.
Hawryluk, M.
Kaszuba, M.
Niechajowicz, A.
Polak, S.
Walczak, S.
Jabłoński, D.
Powiązania:
https://bibliotekanauki.pl/articles/351288.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kucie
optymalizacja
forging
constant velocity joint
optimization
Opis:
This paper presents the results of a search for an optimal shape of the die for forging CVJ (constant velocity joint) casings. The aim of the optimization was to increase tool life by reducing the pressures acting on the die. Therefore the minimization of the forging force was adopted as the optimization criterion. In order to verify the optimization results, the graphs of the calculated forging forces were compared with the real forging force registered by a dedicated measuring & archiving system. Then new dies with the optimal shape obtained from the numerical modelling were made and used in the industrial forging process. It was found that the maximum forging force values for the optimized dies were by about 10-15% lower than the ones for the dies with the original shape, which indicates an increase in die durability.
W pracy przedstawiono wyniki poszukiwania optymalnego kształtu matrycy dla procesu kucia obudowy przegubu homokinetycznego. Optymalizację przeprowadzono pod kątem zwiększenia trwałości narzędzi poprzez zmniejszenie obciążeń na narzędziach. Jako kryterium optymalizacyjne przyjęto minimalizację siły kucia, której wartość zależy między innymi od kształtu matrycy. Następnie wykonano nowe matryce z optymalnym kształtem uzyskanym z modelowania numerycznego i zrealizowano przemysłowy proces kucia dla zoptymalizowanych kształtów. Przeprowadzone badania wykazały, że maksymalne wartości sił kucia w drugiej operacji dla nowych narzędzi są mniejsze o około 10-15% w porównaniu do sił uzyskiwanych dla wcześniejszych kształtów matryc, co z kolei wskazuje na zwiększenie ich trwałości.
Źródło:
Archives of Metallurgy and Materials; 2011, 56, 2; 551-558
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Microstructure and Magnetoelectric Properties of Multiferroic Composites
Autorzy:
Bartkowska, J. A.
Bochenek, D.
Niemiec, P.
Powiązania:
https://bibliotekanauki.pl/articles/355756.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
composites
dielectric constant
magnetoelectric coupling coefficient
multiferroics
Opis:
Multiferroic composites are very promising materials because of their applicability because the magnetoelectric effect occurs in them. The subject of the study were two multiferroic ceramic composites: leaded obtained from powder of the composition PbFe0.5 Nb0.5 O3 and ferrite powder of the composition Ni0.64 Zn0.36 Fe2 O4 and unleaded which was obtained from the powder of the composition BaFe0.5 Nb0.52 O3 and the same ferrite powder Ni0.64 Zn0.36 Fe2 O4. For the both multiferroic materials the following studies were conducted: SEM, BSE, EDS, XRD and the temperature dependence of dielectric constant ε(T). Using the previously developed method of calculating the magnetoelectric coupling factor (g), based on dielectric measurements, the magnitude of the magnetoelectric effect in the multiferroic composites was determined.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 853-858
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Subgraph densities in hypergraphs
Autorzy:
Peng, Yuejian
Powiązania:
https://bibliotekanauki.pl/articles/743780.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Erdös jumping constant conjecture
Lagrangian
optimal vector
Opis:
Let r ≥ 2 be an integer. A real number α ∈ [0,1) is a jump for r if for any ε > 0 and any integer m ≥ r, any r-uniform graph with n > n₀(ε,m) vertices and density at least α+ε contains a subgraph with m vertices and density at least α+c, where c = c(α) > 0 does not depend on ε and m. A result of Erdös, Stone and Simonovits implies that every α ∈ [0,1) is a jump for r = 2. Erdös asked whether the same is true for r ≥ 3. Frankl and Rödl gave a negative answer by showing an infinite sequence of non-jumps for every r ≥ 3. However, there are still a lot of open questions on determining whether or not a number is a jump for r ≥ 3. In this paper, we first find an infinite sequence of non-jumps for r = 4, then extend one of them to every r ≥ 4. Our approach is based on the techniques developed by Frankl and Rödl.
Źródło:
Discussiones Mathematicae Graph Theory; 2007, 27, 2; 281-297
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reachability of standard and fractional continuous-time systems with constant inputs
Autorzy:
Rogowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/230075.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
constant input
reachability
fractional system
positive system
Opis:
The reachability of standard and fractional-order continuous-time systems with constant inputs is addressed. Positive and non-positive continuous-time linear systems are considered. Necessary and sufficient conditions for the existence of such constant inputs that steers the system from zero initial conditions to the given final state in desired time are derived and proved. As an example of such systems the electrical circuits with DC voltage sources are presented
Źródło:
Archives of Control Sciences; 2016, 26, 2; 147-159
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of activity coefficient and equilibrium constant models on the speciation of aqueous solutions of H2SO4–MgSO4–Al2(SO4)3 at 235 and 250 °C
Autorzy:
Dickson, Okechukwu Vincent
Deleau, Thomas
Coquelet, Christophe
Espitalier, Fabienne
Lombart, Julien
Tardy, Antoine
Powiązania:
https://bibliotekanauki.pl/articles/24085644.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
activity coefficient
equilibrium constant
hydrometallurgy
speciation
thermodynamics
Opis:
Supersaturation occurs in many industrial applications promoting reactive crystallisation between the reactants to form solutes. These solutes accumulate during precipitation, leading to the formation of scales on the inner walls of the reactor and particularly around the stirrer, causing modifications in the hydrodynamics. This encrustation is responsible for process shutdowns in continuous crystallisation processes. Supersaturation control is essential for industrial processes aimed at controlling or inhibiting the formation of these solids. Knowledge of mineral solubility and chemical speciation is required to account for the composition of the complexes in the system in their various solid or aqueous forms. This speciation is obtained by considering the thermodynamic equilibrium constants of the dissociation/complexation reactions involved in the system, the pressure, and the activity coefficients of the chemical species in their molecular or electrolyte form. From these thermodynamic quantities and the state of the system, we can predict the direction of the reaction. This study highlights the risk of the lack of experimental information on equilibrium constants at high temperatures and moderate pressures. Our goal is to evaluate the accuracy of existing models classically used to predict the equilibrium constant in such very hard conditions encountered in hydrometallurgical processes. Furthermore, we demonstrate the influences of equilibrium constants estimation and activity coefficient models on the speciation of H2SO4–Al2(SO4)3–MgSO4 systems, forming hydronium alunite and kieserite in the laterite liquor of hydrometallurgical processes.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 5; art. no. 167497
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-adiabatic universe and the redshift
Autorzy:
Gupta, Rajendra P.
Powiązania:
https://bibliotekanauki.pl/articles/1163142.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Cosmic microwave background radiation
Cosmological constant
Cosmology theory
Distance scale
Distances and redshifts
Galaxies
General relativity
Hubble constant
Supernovae
Opis:
We have relaxed the constraint of adiabatic universe used in most cosmological models and shown that the new approach provides a better fit to the supernovae Ia redshift data with a single parameter, the Hubble constant, than the standard ΛCDM model with two parameters, the Hubble constant and the cosmological constant. The new approach, developed within the confines of the cosmological principle, yields the Hubble constant value 69.01 (±0.53) km s-1 Mpc-1. The cosmological constant may thus be considered as a manifestation of a non-adiabatic universe that is treated as an adiabatic universe.
Źródło:
World Scientific News; 2018, 110; 210-218
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 348

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