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Wyszukujesz frazę "size effect" wg kryterium: Temat


Tytuł:
Size effect at testing strength properties of concrete
Autorzy:
Akram, Amanda
Powiązania:
https://bibliotekanauki.pl/articles/1955920.pdf
Data publikacji:
2021
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
concrete
size effect
tensile strength
Opis:
Various strength characteristics of concrete are considered as fracture parameters. The compressive strength of concrete is of paramount importance when designing concrete structures, whereas tensile strength of concrete is the basic property when estimating cracking resistance of a structure and analysing fracture processes in concrete. When testing the compressive strength of concrete, the results are dependent on the shape and dimensions of used specimens. Some findings reported in the literature suggest that size effect exists also when testing such fracture properties of concrete as tensile strength. Unfortunately this problem is much less recognized and described compared to size effect in compressive test results. In this paper, the experimental investigation is presented on how the length of cylindrical specimens influences the tensile splitting strength of concrete obtained by means of the Brazilian method. Additional variable parameters were: type of aggregate (natural gravel and crushed granite) and cement-water ratio (C/W = 1.8 and C/W = 2.6). In conducted laboratory experiments a higher splitting tensile strength of concrete was noted for all specimens with nominal dimensions of 150×150 mm, compared to specimens 150×300 mm in size, regardless of type of aggregate or cement-water ratio.
Źródło:
Budownictwo i Architektura; 2021, 20, 4; 37-45
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Importance of the Size of Local Government in Avoiding the Fiscal Distress - Empirical Evidence on Communes in Poland
Autorzy:
Galiński, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/16729115.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
fiscal distress
local government
size effect
Opis:
Theoretical background: In the literature on finance there are findings which examine reasons for the fiscal distress of units of the public sector, including local governments. However, this distress might be differently defined. Therefore, it determines both the approach to identify this phenomenon and the types of explanatory variables. Nevertheless, in the field of the business sector in the econometric models concerning the financial distress the size of the unit is considered. In this case there are also some possibilities to apply the correct proxy variable. This results from the fact that the size of local government might determine its fiscal capability as well as the level and structure of expenditures, which affect fiscal distress. Purpose of the article: The aim of this paper is to examine the influence of the size of the local government on the probability of the decrease of the exposure to the fiscal distress. Research methods: The author reviewed the literature in the field of the fiscal distress and introduced a multi-criteria decision analysis as well as a logistic regression modelling to examine this. The research procedure also required the use of the linear ordering to construct the dependent variable of the fiscal distress in order to analyse the “size effect” on the fiscal distress. Main findings: Fiscal distress of local governments is a core issue, which should be constantly analysed. It depends on the financial, economic, social and even political aspects. To identify exposure to this distress the TOPSIS method can be used. However, the fiscal distress can be affected by the size of the unit, which influences lots of budgetary categories. Due to the specificity of dependent and independent variables in the econometric models the “size effect” might be represented through the level of the population or the assets. Using the ordinal logistic regression in the research, the authors should consider that this effect can differ between the units with the disparate exposure. So, the partial proportional odds models can be required. Thus, the growth of the size of the unit, measured by the population, increases the odds of reaching very low exposure to fiscal distress. Simultaneously, there are some other important issues which should be included in this type of research.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio H – Oeconomia; 2022, 56, 5; 101-113
0459-9586
2449-8513
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio H – Oeconomia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ubiquitiformal fracture energy
Autorzy:
Ou, Z.-C.
Yang, M.
Li, G.-Y.
Duan, Z.-P.
Huang, F-L.
Powiązania:
https://bibliotekanauki.pl/articles/280189.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
fractal
ubiquitiform
fracture energy
size effect
Opis:
The ubiquitiformal fracture energy is proposed in the paper and its explicit expression is obtained. Moreover, the numerical results for concrete are found to be in good agreement with those for the critical strain energy release rate. The discrepancy between the numerical results of the traditional fracture energy and the critical strain energy release rate can be explained reasonably, which implies that the ubiquitiformal fracture energy should be taken as an available fracture parameter of materials. Finally, it is numerically found for some concrete that there is not size effect for the ubiquitiformal fracture energy.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 3; 1101-1108
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inner Size Effect in Layered Films with Eutectic Interaction of Components
Autorzy:
Dukarov, S.
Petrushenko, S.
Sukhov, V.
Churilov, I.
Samsonik, A.
Skryl, O.
Powiązania:
https://bibliotekanauki.pl/articles/1030004.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
inner size effect
multilayer films
interfacial energy
Opis:
The results of the study of melting of Bi-Sn and Pb-Sn polycrystalline layered film systems with the thickness of 200-400 nm on a substrate with temperature gradient are given. Multilayer (each layer is of 10-20 nm) and bilayer films (layers are of 100-200 nm) of the same total thickness have been investigated. Broadening of the melting range in all films and lowering of melting point in multilayer samples compared to the bilayer ones have been observed. The observed phenomena are discussed within existing thermodynamic concepts in consideration of interfacial energy of contacting layers of components and energy of grain boundaries in polycrystalline films.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1186-1190
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On some problems in determining tensile parameters of concrete model from size effect tests
Autorzy:
Marzec, Ireneusz
Bobiński, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/260481.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
concrete
size effect
fracture energy
elasto-plasticity
XFEM
Opis:
The paper presents results of numerical simulations of size effect phenomenon in concrete specimens. The behaviour of in-plane geometrically similar notched and unnotched beams under three-point bending is investigated. In total 18 beams are analysed. Concrete beams of four different sizes and five different notch to depth ratios are simulated. Two methods are applied to describe cracks. First, an elasto-plastic constitutive law with a Rankine criterion and an associated flow rule is defined. In order to obtain mesh independent results, an integral non-local theory is used as a regularisation method in the softening regime. Alternatively, cracks are described in a discrete way within Extended Finite Element Method (XFEM). Two softening relationships in the softening regime are studied: a bilinear and an exponential curve. Obtained numerical results are compared with experimental outcomes recently reported in literature. Calculated maximum forces (nominal strengths) are quantitatively verified against experimental values, but the force – displacement curves are also examined. It is shown that both approaches give results consistent with experiments. Moreover, both softening curves with different initial fracture energies can produce similar force-displacement curves.
Źródło:
Polish Maritime Research; 2019, 2; 115-125
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of dynamic growth of a micro-scaled void based on strain gradient elasto-plasticity
Autorzy:
Ma, Xinbing
Liu, Jinxing
Wang, Jiadong
Pan, Hao
Powiązania:
https://bibliotekanauki.pl/articles/1839598.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
dynamic void growth
size effect
inertia
thermal softening
Opis:
Void initiation and growth serve as an important mechanism in ductile failures in metals. Particularly, on the micron-level, the extra hardening effect associated with strain gradient is accounted for by adopting strain gradient elasto-plasticity instead of the conventional plasticity. Effects of inertial, strain gradient hardening and thermal softening are formulated analytically for the case where a spherical void expands under external hydrostatic stress. As demonstrated by our results, the inertia effect firstly tends to hinder but then promotes the void growth. The threshold stress required for rapid void growth is lifted due to extra hardening of strain gradient so that the growth of a smaller void is delayed more remarkably. A considerable thermal softening phenomenon is observed here, which is caused by plastic work during the deformation process. The final void growth rate is mainly related to the maximum loading, which is consistent with the prediction based on the classical plastic theory.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 4; 927-941
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of particle size and feed rate on coal cleaning in a dry separator
Autorzy:
Kademli, M.
Gulsoy, O. Y.
Powiązania:
https://bibliotekanauki.pl/articles/110339.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
dry coal cleaning
particle size effect
air separator
Opis:
This research is concerned with the effects of particle size distribution and feed rate of feed on the coal cleaning performance of table type air separator. In tests, the lignite and hard coal samples from Mugla and Zonguldak districts in Turkey were used. The samples were tested in three different size distributions such as –38 + 6 mm, –19 + 6 mm and –9.5 + 6 mm. The effect of particle size was investigated together with the feed rate 2 Mg/(hm2), 1.68 Mg/(hm2) and 1.32 Mg/(hm2) and very important physical parameters of table type air separator such as, riffle height, table slope and table frequency. Results were analyzed by using the Tromp curve for indicating the effects in detail. Consequently, the results revealed that the particle size had remarkable effect on separation efficiency. The separation efficiency was, however, inversely affected as the particle size distribution became finer, and the best results were obtained in particle size distribution was –38 + 25 mm in both sample tested. The Ep value was 0.11 for the hard coal samples while it was 0.13 for the lignite samples.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 204-213
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of pre-tension on torsion of microscale Cu wires: a study via strain gradient theory
Autorzy:
Ma, Xinbing
Liu, Jinxing
Powiązania:
https://bibliotekanauki.pl/articles/280360.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
nonproportional loading
strain gradient plasticity
size effect
cyclic response
Opis:
Nonproportional plastic deformations on the microscale are an emerging topic. A simplified theory of strain gradient elasto-plasticity is developed to study the evolution of yield strength in a copper wire sequentially experiencing tension and torsion. The pre-tension deformation and stress are inherited to the upcoming torsion process, resulting in a nonproportional loading condition. With consideration of the extra hardening effect due to strain gradient, pre-tension weakens the extra hardening effect of the strain gradient and the dependence on the wire radius. Cyclic torsion behavior is also investigated. Anomalous Bauschinger effect and plastic softening are found.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 4; 1055-1065
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue life prediction of aluminium profiles for mechanical engineering
Autorzy:
Tomaszewski, T.
Sempruch, J.
Powiązania:
https://bibliotekanauki.pl/articles/281070.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
aluminium profile
high-cycles fatigue
mini specimen
size effect
Opis:
The study presents a method to determine the σa − N curve (high cycle fatigue) for profiles made of AW-6063 T6 aluminium alloy. Experimental material data for a mini specimen taken directly from the tested item and selected empirical correlations allowing for a size effect have been used. A model yielding the lowest relative error of estimating the fatigue life is presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 497-507
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on optimization method of flotation kinetic model based on molybdenite particle size effect
Autorzy:
Wan, He
An, Yanni
Qu, Juanping
Zhang, Chonghui
Xue, Jiwei
Wang, Sen
Bu, Xianzhong
Powiązania:
https://bibliotekanauki.pl/articles/24085892.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
particle size effect
molybdenite
mathematical model
method of correction
Opis:
Flotation kinetic models can be applied to describe the flotation process and to predict mineral recoveries. However, the size composition of the target minerals in the feed ore fluctuates considerably, resulting in insufficient accuracy with flotation kinetic models. There have been many studies that focus on the investigation of flotation kinetics with different particle sizes, while the optimization methods for flotation kinetic models based on particle size effects have not been reported. In this paper, flotation tests, optical microscope observations, and particle size analysis were used to identify the reasons for the decrease in accuracy of the flotation kinetic model due to changes in the composition of molybdenite particle size. Additionally, an optimization method for the flotation kinetic model was developed based on the particle size effect. The test results show that the accuracy of the flotation kinetic model for fixed particle size minerals is very high, but the predicted results for flotation recoveries of different particle size mineral mixtures have large deviations. The poor accuracy might be due to the autogenous carrier effect caused by the particle size composition fluctuating considerably. The optimization method for the flotation kinetic model is based on the particle size effect. The model can accurately describe the flotation process of molybdenite with different size compositions of molybdenite and predict the flotation recovery of molybdenite.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 2; art. no. 163004
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
2D Lattice Model for Fracture in Brittle Materials
Autorzy:
Kozicki, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/241484.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
beam
brittle material
discrete method
fracture
lattice model
size effect
Opis:
The numerical simulations show the potential of a lattice discrete approach to model fracture during brittle materials in different two-dimensional quasi-static processes of loading behaviour. The 2D calculations were carried out for brittle specimens subject to uniaxial compression, uniaxial extension and shear. The effect of the specimen size on the global stress-strain diagram during uniaxial tension was also investigated. The advantages and disadvantages of the model were outlined.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 2; 137-154
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Physical Properties of Copper Oxide Thin Films Prepared by Electrolysis Method
Autorzy:
Oudah, Mustafa H.
Mazin, H. Hasan
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1065248.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
copper oxide
drop-casting method
electrolysis
quantum size effect
thin films
Opis:
The aim of this paper is to study the properties of copper oxide thin films prepared by electrolysis method and deposited on glass substrates by drop-casting method at different annealing temperatures. Copper oxide colloidal was successfully prepared by electrolysis method. The X-ray diffraction confirms the polycrystalline structure of the films. Atomic force microscopy shows that the increase in the annealing temperature improves the surface morphology, increases the grain size and removes the cracks. The best optical transmittance was for the film annealed at 200 ºC. The bandgap decreases from 3.35 eV to 3.15 eV as a result of increasing the annealing temperature. The wide bandgap that obtained in this study is due to quantum size effect.
Źródło:
World Scientific News; 2019, 135; 59-70
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dependence of creep failure probability on the size of metallic specimens
Autorzy:
Nowak, K.
Powiązania:
https://bibliotekanauki.pl/articles/387437.pdf
Data publikacji:
2013
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
size effect
creep damage
cellular automata
efekt rozmiarowy
zniszczenie przy pełzaniu
pełzanie
Opis:
The occurrence of statistical size effect is considered for damage in creep conditions. The numerical and experimental analysis have been performed. The obtained results are ambiguous. Numerical models confirm the scale effect which can be statistical or deterministic one. But this effect has no experimental verification. It may suggest that the weakest link model cannot be applied in creep conditions. Explanation of this needs further investigations.
Źródło:
Acta Mechanica et Automatica; 2013, 7, 3; 166-169
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The experimental tool for micro-extrusion of metals
Autorzy:
Piwnik, J.
Mogielnicki, K.
Gabrylewski, M.
Baranowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/381943.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microforming
microextrusion
size effect
experimental tool
mikroformowanie
mikrowyciskanie
efekt skali
narzędzie doświadczalne
Opis:
In paper the technological tools requirements, used for micro-extrusion of metals in cold and warm conditions are presented. The constructive principles for the micro-tools are also described. The influence of the size effect in a workpiece and a tool top layers roughness form on extrusion processes in microscale are showed. The tool, designed to an experimental verification of the size effect influence, in a tool roughness form, on the metal rod forward extrusion are presented. This tool is made in the form of two halves, joined together by the pegs and screws. It has bored two dies profiles with the same dimensions, the only difference is a degree of the containers roughness. That solution gives a possibility to specify the influence of the tool roughness degree on the extrusion forces, deformation process and a product quality. Described tool was designed in such a way to manufacture it with using conventional machining equipment.
Źródło:
Archives of Foundry Engineering; 2011, 11, 2 spec.; 195-198
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the size effect of auxetic cellular materials
Autorzy:
Janus-Michalska, M.
Powiązania:
https://bibliotekanauki.pl/articles/265410.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
negative Poissons ratio
auxetic structures
size effect
właściwości sprężyste
próba ścinania
kompresja
Opis:
The objective of this paper is to investigate the effects of scale of an auxetic cellular material sample on the evaluation of elastic properties. Size and boundary effects are studied in detail. This is achieved by conducting computer simulations of the auxetic structure under the typical loading exerted by the compression and simple shearing test performed by means of ABAQUS FEA. The material microstructure is discretized by the plane network of Timoshenko beam elements. The results of the studies give insight to the scale effects. Structures with designed properties can be potentially used for engineering applications.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 3; 749-757
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulations of the Effects of Droplet Size and Concentration on Vapour-Droplet JP-10/Air Detonations
Autorzy:
Liu, L.
Zhang, Q.
Powiązania:
https://bibliotekanauki.pl/articles/358150.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
multiphase detonation
discrete phase model
evaporation and breakup model
droplet size effect
initial concentration effect
Opis:
Two-dimensional simulations were conducted for JP-10 mono-dispersed vapour-droplet detonation in air, based on the detonation mechanism for clouds and validation of the extending critical droplet size limits in previous tests. In the simulations, the discrete phase model combined with the droplet evaporation and droplet breakup models was used. Utilizing a wide range of mono-dispersed droplet sizes and initial droplet concentrations, all cases of JP-10 droplets with a certain amount of pre-vaporized fuel can successfully achieve the deflagration to detonation transition. Detonation velocities at the equivalent concentration with droplet diameters no larger than 50 μm are in good agreement with the theoretical detonation velocities. The effects of droplet size and initial droplet concentration on the detonation behaviour were also investigated. Detonation velocities attained with droplet diameters below 50 μm appear to decrease very slightly with droplet size, but are almost equal to the velocity in gases. When the droplet diameter is above 50 μm, there is a decrease in simulated detonation velocity compared with fine droplets, and no secondary pressure peak was observed. For fuel-rich combustion, detonation velocities decrease rapidly with an increase in initial droplet concentration, and post-wave pressure fluctuation was obviously irregular, caused by the secondary local explosion of the droplets.
Źródło:
Central European Journal of Energetic Materials; 2018, 15, 1; 175-190
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carbon nanotubes with controlled length – preparation, characterization and their cytocompatibility effects
Autorzy:
Cendrowski, K.
Jedrzejczak-Silicka, M.
Powiązania:
https://bibliotekanauki.pl/articles/778531.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Multiwalled carbon nanotubes
cutting carbon nanotubes
size effect
mitochondrial activity
biocompatibility
apoptosis
necrosis
Opis:
Multiwalled carbon nanotubes (MWCNTs) have attracted huge attention due to their multifunctionality. Their unique properties allows for covalent and noncovalent modifi cations. The most simple method for functionalization of carbon nanotubes is their decoration with the oxygen containing moieties which can be further simultaneously functionalized for design of new class carriers for targeting and imaging. Here, we present methodology for chopping nanotubes, characterization of MWCNTs, the effect of size on the biocompatibility in culture of L929 mouse fi broblasts using WST-1, LDH and apoptosis assays. The analysis provides the optimal carbon nanotubes length and concentration which can be used for functionalization in order to minimize the effect of the secondary agglomeration when interacting with cells.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 2; 71-79
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Size Effects in Problems of Footings on Sand within Micro-Polar Hypoplasticity
Autorzy:
Tejchman, J.
Górski, J.
Powiązania:
https://bibliotekanauki.pl/articles/241079.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
footing
micro-polar hypoplasticity
sand
shear localization
size effect
stratified sampling
void ratio
Opis:
Numerical FE investigations of size effects in problems of footings on sand were performed. Micro-polar hypoplastic constitutive model was used to describe a mechanical behaviour of a cohesionless granular material during a monotonic deformation path. The FE analyses were carried out with three different footing widths. In deterministic calculations, a uniform distribution of initial void ratio was used. In statistical calculations, initial void ratios took the form of random spatial fields described by a truncated Gaussian random distribution. In order to reduce the number of stochastic realizations without sacrificing the accuracy of the calculations, a stratified sampling method was applied. The numerical results were compared with corresponding laboratory tests by Tatsuoka et al (1997). The numerical results show that the bearing capacity of footings decreases with increasing specimen size. If the initial void ratio is stochastically distributed, the mean bearing capacity of footings may be larger than the deterministic value. The statistical size effect is smaller than the deterministic one.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2008, 55, 3-4; 95-124
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A shifted Wald decomposition of the numerical size-congruity effect: Support for a late interaction account
Autorzy:
Faulkenberry, Thomas J.
Vick, Adriana D.
Bowman, Kristen A.
Powiązania:
https://bibliotekanauki.pl/articles/2129181.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Size congruity effect
response time modeling
accumulator model
shifted Wald distribution
Opis:
Decisions involving comparisons of Arabic number digits often exhibit an interference between the physical size of the digit and the implied numerical magnitude, a phenomenon called the size-congruity effect. Related research over the past four decades has yielded two competing models of the phenomenon: an early interaction account, where interference between numerical and physical magnitude occurs at an early encoding stage, and a late interaction account, where the interference occurs downstream as response competition during the decision process. In the present study, we asked participants to compare the physical sizes of pairs of Arabic digits. We fit the resulting response time distributions with a shifted Wald model, a single boundary accumulator model, which gave us estimates of information accumulation rate (drift rate), response threshold, and nondecision time. We found that incongruity between physical size and numerical magnitude affected the decision-related estimates of drift rate and response threshold. Further, a Bayesian analysis confirmed a null effect of congruity on nondecision time. These results indicate that the observed interference originates from decision-related processes, lending further support for a late interaction account of the size-congruity effect.
Źródło:
Polish Psychological Bulletin; 2018, 49, 4; 391-397
0079-2993
Pojawia się w:
Polish Psychological Bulletin
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
VOCABULARY GLOSSING: A META-ANALYSIS OF THE RELATIVE EFFECTIVENESS OF DIFFERENT GLOSS TYPES ON L2 VOCABULARY ACQUISITION
Autorzy:
Vahedi, Vahideh Sadat
Ghonsooly, Behzad
Pishghadam, Reza
Powiązania:
https://bibliotekanauki.pl/articles/955891.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej w Lublinie. IATEFL Poland Computer Special Interest Group
Tematy:
hypertext gloss
vocabulary acquisition
meta-analysis
effect size
heterogeneity
Opis:
In recent years there has been a growing interest to incorporate hypertext glosses into L2 reading materials and accordingly, it has provoked researchers to uncover to what extent and under which moderator variables a specific type of gloss yields more effective outcomes than other types of glossing. The present meta-analysis attempts to examine the magnitude of the effect of different gloss types (single vs. multiple glosses) on L2 vocabulary acquisition along with identification of the contextual factors that influence between-study variation through synthetizing 34 primary articles which satisfy the inclusion criteria. The overall effect size is found to be + 0.83 (p<0.05), indicating that multiple glosses (text+visual) has a large, positive effect on learners’ vocabulary acquisition than single mode of glossing (text-only). Moderator analyses further suggest that intensity of the program and L2 proficiency level are potential moderators influencing the heterogeneity between effect sizes, whereas the learning context, sample size and research design do not have such impact.
Źródło:
Teaching English with Technology; 2016, 16, 1; 3-25
1642-1027
Pojawia się w:
Teaching English with Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Country selection strategies for portfolio management
Autorzy:
Zaremba, Adam
Konieczka, Przemysław
Powiązania:
https://bibliotekanauki.pl/articles/950658.pdf
Data publikacji:
2015
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
value effect
size effect
momentum
volatility effect
anomaly of low risk
inter-market effects
cross-section analysis of returns
factor returns
international diversification
asset pricing
Opis:
This study examines 16 country selection strategies based on inter-market value, size, momentum, quality and volatility effects. We investigate a sample of 78 countries for the period 1999-2014. Having considered country-specific dividend tax rates, market liquidity and openness for investment flows we can state that chosen strategy based on earnings to price ratio proves useful for investors. Momentum strategies should be approached with caution, as they appear effective only in small markets and may lead to loses in large markets. Selecting low leveraged and illiquid countries also proves beneficial. The relation between volatility displays different characteristics for open and closed economies.
Źródło:
Financial Sciences. Nauki o Finansach; 2015, 1(22); 101-119
2080-5993
2449-9811
Pojawia się w:
Financial Sciences. Nauki o Finansach
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Size of Source Effect on Accuracy of LWIR Radiation Thermometers
Autorzy:
Cywiak, D.
Cárdenas-García, D.
Rodriguez-Arteaga, H.
Powiązania:
https://bibliotekanauki.pl/articles/221785.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
size of source effect
radiation thermometer
temperature
field of view
Opis:
Determining the size of source effect of a radiation thermometer is not an easy task and manufacturers of these thermometers usually do not indicate the deviation to the measured temperature due to this effect. It is one of the main uncertainty components when measuring with a radiation thermometer and it may lead to erroneous estimation of the actual temperature of the measured target. We present an empiric model to estimate the magnitude of deviation of the measured temperature with a long-wavelength infrared radiation thermometer due to the size of source effect. The deviation is calculated as a function of the field of view of the thermometer and the diameter of the radiating source. For thermometers whose field of view size at 90% power is approximately equal to the diameter of the radiating source, it was found that this effect may lead to deviations of the measured temperature of up to 6% at 200ºC and up to 14% at 500ºC. Calculations of the temperature deviation with the proposed model are performed as a function of temperature and as a function of the first order component of electrical signal.
Źródło:
Metrology and Measurement Systems; 2016, 23, 4; 661-667
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ wielkości kropli na kinetykę zwilżania w układzie SAC305/Ni
The influence of the drop-size effect on the wetting kinetics in SAC305/Ni system
Autorzy:
Turalska, P.
Sobczak, N.
Kudyba, A
Nowak, R.
Homa, M.
Siewiorek, A.
Boroń, Ł.
Klasik, A.
Powiązania:
https://bibliotekanauki.pl/articles/391805.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa
Tematy:
kinetyka zwilżania
kąt zwilżania
lutowanie bezołowiowe
SAC305
nikiel
efekt wymiarowy kropli
wetting kinetics
contact angle
lead-free soldering
nickel
drop-size effect
Opis:
Badania wpływu efektu wymiarowego kropli na kinetykę zwilżania niklu bezołowiowym stopem na bazie cyny przeprowadzono metodą kropli leżącej w próżni w temperaturze 260°C. Do badań użyto komercyjny stop lutowniczy na bazie cyny SAC305 (Ag – 3,0% wag., Cu – 0,5% wag.) oraz wypolerowane podłoże niklowe o czystości 99,8%. Podczas testu zwilżalności stosowano osobne nagrzewanie badanej pary materiałów do temperatury badań, umieszczając próbkę stopu w kroplówce grafitowej nad powierzchnią podłoża niklowego. Po osiągnięciu wymaganej temperatury z kapilary wyciskano kroplę stopu i osadzano ją na podłożu. Po 30 sekundach wyciskano kolejną kroplę i osadzano ją na pierwszą, zwiększając tym samym objętość kropli dwukrotnie. Proces dokraplania powtarzano 9 razy co 30 sekund, osiągając 10-krotną objętość kropli w porównaniu do stanu pierwotnego. Po badaniach zwilżalności schłodzoną parę materiałów kropla/podłoże przecinano prostopadle do badanej powierzchni podłoża i poddano badaniom na ścinanie oraz analizie strukturalnej poprzecznego przekroju próbki metodami mikroskopii optycznej i skaningowej mikroskopii elektronowej w połączeniu z lokalną analizą składu chemicznego. Badania zwilżalności nie wykazały istotnych różnic wartości kąta zwilżania ciekłego stopu SAC305 na podłożu niklowym po wielokrotnym dokraplaniu, albowiem wartości kąta zwilżania każdorazowo mierzone w 30. sekundzie kontaktu z podłożem Ni były dla wszystkich 10 kropel zbliżone i wynosiły θ = 35 ±2°. Stwierdzona wysoka powtarzalność pomiarów θ świadczy zarówno o braku występowania efektu wymiarowego w badanym zakresie objętości kropli SAC305, jak i o chemicznej i fizycznej jednorodności powierzchni podłoża. Uzyskane wyniki wskazują na przydatność metody kropli leżącej do oceny jakości powierzchni, szczególnie przydatnej do badań jakości cienkich warstw i pokryć technologicznych stosowanych w procesach łączenia różnorodnych materiałów.
The studies of the drop-size effect on the wetting kinetics of the nickel substrate by lead-free solder were performed by the sessile drop method in a vacuum at a temperature of 260°C. In this work, Sn-based alloy SAC305 (Ag – 3.0 wt. %, Cu – 0.5 wt. %) and polished nickel substrate (99.8%) were used. During the wettability tests, a separate heating of the couple of materials to a test temperature was performed by placing a sample of SAC305 alloy in a graphite capillary above the nickel substrate. After reaching the test temperature, the SAC305 drop was squeezed from the capillary and deposited on the Ni substrate. After 30 seconds, the second drop was squeezed and deposited on the first one, thereby increasing the volume of the drop twice. The process was repeated 9 times every 30 seconds reaching a 10 times larger drop volume, compared to the first drop. After wettability tests, the solidified drop/substrate couple was cooled, cut and subjected to a shear test and structural analysis by optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy analysis. Wettability studies have not shown a significant difference between the values of the contact angle obtained for each drop produced by subsequent adding of nine drops despite their different size of ten drops produced on the substrate, their contact angle values formed after 30 second contact time were similar showing θ = 35 ±2°. High repeatability of the measured contact angle value θ demonstrates not only physical homogeneity of the substrate surface but it presents a lack of size effect over a range of SAC305 drop volume used in this study. The obtained results demonstrate the suitability of the sessile drop method for surface quality evaluation, particularly for quality tests of thin technological layers or coatings used in joining dissimilar materials.
Źródło:
Prace Instytutu Odlewnictwa; 2015, T. 55, nr 2, 2; 3-17
1899-2439
Pojawia się w:
Prace Instytutu Odlewnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nośność na przebicie krępych płyt żelbetowych – badania i analiza metodą S-T
Punching shear behavior of thick reinforced concrete slabs according to Strut-and-Tie model
Autorzy:
Urban, T.
Krakowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/391037.pdf
Data publikacji:
2014
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
metoda kratownicowa (strut-and-tie)
przebicie osiowe
smukłość ścinania
fundament
efekt skali
Strut-and-tie model
punching shear
shear slenderness
footing
size effect
Opis:
W pracy przedstawiono próbę analizy nośności na przebicie płyt krępych za pomocą metody kratownicowej (strut-and-tie, S-T). Procedura obliczeniowa została porównana z wynikami własnych badań eksperymentalnych. Zakres analizy obejmuje wyłącznie elementy bez zbrojenia poprzecznego obciążone osiowo symetrycznie.
The punching shear behavior of thick reinforced concrete slabs was analyzed in this paper by using strut-and-tie model (S-T). Calculating procedures were compared to our own experimental test results. The analyzed elements were subjected to symmetric loading and without shear reinforcement.
Źródło:
Budownictwo i Architektura; 2014, 13, 3; 183-191
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wybrane wskaźniki wielkości efektu w badaniach psychologicznych
Autorzy:
Prajzner, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/33951763.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
effect size
null hypothesis
statistical analysis
psychological research
wielkość efektu
hipoteza zerowa
analiza statystyczna
badania psychologiczne
Opis:
Odzwierciedlając zmieniającą się praktykę statystyczną w badaniach psychologicznych, w której dominuje testowanie hipotez zerowych z wykorzystaniem decyzji o poziomie istotności wyników, wskazano zalecenia dotyczące raportowania w pracach wielkości efektu. W opracowaniu przedstawiono pojęcie wielkości efektu oraz wskazano miejsce, jakie zajmuje w analizie danych w odniesieniu do istotności wyników. Celem pracy jest opisanie wybranych wskaźników wielkości efektu, a także wskazanie potrzeby zastosowania i poprawnej ich prezentacji i interpretacji w raporcie analiz prac empirycznych z zakresu nauk społecznych. Biorąc pod uwagę ograniczenia podejścia statystycznej analizy danych opartej jedynie na poziomie istotności, w opracowaniu zaprezentowano możliwości umieszczania w analizach danych wskaźnika o większym praktycznym zastosowaniu, jakim jest wielkość efektu. Wykorzystując najbardziej popularne metody analityczne, takie jak testy t Studenta, jednoczynnikowe analizy wariancji w schematach między- i wewnątrzgrupowych, a także analizy testem Wilcoxona, U Manna-Whitneya, H Kruskala-Wallisa, testem Friedmana oraz uwzględniając analizy dla danych jakościowych, zaprezentowano dobrane do planów badawczych wskaźniki wielkości efektu. Ponadto opisano wykorzystanie, sposób obliczania oraz interpretację wybranych wskaźników wielkości efektu, jakimi są wskaźniki: d Cohena, g Hedgesa, delta, rg Glassa, korelacja par dopasowanych rc, eta-kwadrat, omega-kwadrat oraz epsilon-kwadrat, W Kendalla oraz fi, V Cramera czy iloraz szans i ryzyko względne. Prezentację wskaźników wielkości efektu zestawiono z odpowiadającymi im planami badawczymi i rodzajem zebranych danych.
Reflecting the changing statistical practice in psychological research, dominated by null hypothesis testing using a decision about the level of significance of the results, the recommendations are indicated for reporting effect sizes in papers. The study presents the concept of the effect size and indicates its place in data analysis regarding to outcome’s significance. The purpose of the work is to describe selected effect size indicators and to point the need of use and their proper presentation and interpretation in social sciences empirical work data analysis reports. Considering statistical analysis approach limits based on significance level only, the study presents the possibility of including in the data analysis an indicator of a more practical use which is the size of the effect. By using the most popular analysis methods, such as, Student t-test, univariate analyses of variance in between- and within-group schemes as well as Wilcoxon test, Mann-Whitney’s U, Kruskal-Wallis H, Friedman’s test and considering analysis for qualitative data, matched to research plans indicators of the effect size were presented. The paper presents the use, calculation and interpretation of the size effect such as: Cohen’s d, Hedges g, delta, Glass’s rg, matched pairs correlation rc, eta-square, omega-square and epsilon-square, Kendall’s W and fi, Cramer’s V as well as odds ratio and relative risk. The presentation of the effect size indicators was contrasted with the corresponding research plans and the type of data collected.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio J – Paedagogia-Psychologia; 2022, 35, 4; 139-157
0867-2040
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio J – Paedagogia-Psychologia
Dostawca treści:
Biblioteka Nauki
Artykuł

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