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Tytuł:
Analytical forms of deuteron wave function and density distribution
Autorzy:
Zhaba, V. I.
Powiązania:
https://bibliotekanauki.pl/articles/1177883.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
analytic form
approximation
density distribution
deuteron
transition density
wave function
Opis:
Values of density distribution and transition density are calculated using the obtained coefficients of four deuteron wave function for analytical forms in coordinate representation for Argonne v18 potential. Calculations of these values can serve for an assessment of a correctness and accuracy of choice of an analytical form at concrete approximation of radial deuteron wave function. Also these calculations help to evaluate information on such characteristics of a deuteron as a charge form factor, tensor polarization and momentum distribution.
Źródło:
World Scientific News; 2018, 98; 206-213
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Modified Penetration Model for Copper-Tungsten Shaped Charge Jets with Non-uniform Density Distribution
Autorzy:
Elshenawy, T.
Elbeih, A.
Li, Q. M.
Powiązania:
https://bibliotekanauki.pl/articles/358894.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
shaped charge
jet penetration
virtual origin
non-uniform density distribution
Opis:
The penetration of a shaped charge jet with non-uniform density distribution was studied. The virtual origin model, which assumes a constant jet density, was modified to include the situation where the jet density deficit/reduction of an un-sintered copper-tungsten powder jet causes a non-uniform jet density distribution. A relation between the relative density ratio and the normalised jet velocity is proposed, based on which an analytical solution of the modified virtual origin model is obtained. The validity of the modified virtual origin model was demonstrated by its largely improved prediction in comparison with experimental and numerical results. It showed that the density reduction term reduces the penetration depth by 16.58% for an un-sintered copper-tungsten powder jet.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 4; 927-943
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dry beneficiation and cleaning of chinese high-ash coarse coal utilizing a dense-medium gas-solid fluidized bed separator
Autorzy:
He, J.
Tan, M.
Zhu, R.
Luo, Z.
Powiązania:
https://bibliotekanauki.pl/articles/110808.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal cleaning
dense-medium fluidized bed
density distribution
segregation
separation performance
Opis:
Dry dense-medium fluidized bed separation provides a new alternative approach for coal beneficiation and cleaning. An indicator of segregation degree Sash was proposed to evaluate the stratified performance of coal samples by bed density. Fluidization stability of the bed was greatly enhanced by mixing a certain amount (21.53%) of fine magnetite powder (< 0.15 mm) into the fluidized media, which indicated a uniform density distribution as well as slight fluctuations in bed. It was found that the favorable density-segregation performance of 3–13 mm coarse coal occurred with a static bed height of 80 mm and a superficial gas velocity of 11.84 cm/s. The optimal segregation degree values of 0.67, 0.74 and 0.76 were obtained for 3–6, 6–10 and 10–13 mm coal samples, respectively. Low-ash clean coal with yields of 50.79, 56.83 and 61.24% were effectively acquired by the dry separation for various coal size fractions, respectively. Probable error values of 0.07, 0.055 and 0.05 g/cm3 were achieved, indicating good separation performance.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 2; 662-675
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coronal Electron Density Distribution Estimated from Meter Type II Radio Bursts and Coronal Mass Ejections
Autorzy:
Yusof, N. S.
Hamidi, Z. S.
Norsham, N. A.
Jafni, A. I.
Kahlid, N. M.
Hamdan, M. N.
Kamaruddin, Farahana
Tahar, Muhammad Redzuan
Monstein, C.
Shariff, N. N. M.
Powiązania:
https://bibliotekanauki.pl/articles/1192681.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
coronal mass ejection
Type II radio burst
electron density distribution
e-CALLISTO
Opis:
In this paper, we investigate the characteristic coronal mass ejection and Type II radio burst, we calculated the drift rate of Type II Radio burst and determined the electron density distribution from a Coronal Mass Ejections. The data were taken from website e-CALLISTO, Space Weather, SolarHam and also from the Langkawi National Observatory, National Space Agency, Langkawi Kedah, Malaysia. All the data collected on 15th March 2015, 4th November 2015 and 16th December 2015. On 16 March 2015, the events were associated with slower C9 solar flare and CME. For this week, the events were causing radio blackouts on Earth. On 4 November 2015, the events were associated with M1.9 solar flare, CME and Solar burst Type II. The value of the solar wind was 570.4 km/Sec and value for radio sun was 124 sfu. For drift rate, we calculated the value for sites in Sri Lanka (ACCIMT-SRI), Ooty, India (OOTY), Indonesia (INDONESIA) and Kasi, South Korea (KASI) at between 0324 to 0328 UTC. In South Korea was highest drift rate, which is 1.397 MHz/s. Also, at HB9SCT, Switzerland (HB9SCT), Humain, Belgium (Humain), Daro, Germany (Daro-VHF) and TCD in Birr, Ireland (BIR), we calculated the drift rate of solar burst Type II between 1200 until 1203 UTC. In Belgium had the highest value of the drift rate to compare at other sites. Harmonic pattern was also appeared for all these sites. On 16th December 2015, this event associated with C6.6 solar flare and CME. These events give an impact on the earth geomagnetic field which is formed of aurora because of the combination of both events that trigger geomagnetic storming.
Źródło:
World Scientific News; 2016, 46; 19-35
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of coal mineral matter liberation efficiency index
Ocena stopnia uwolnienia frakcji mineralnej węgla
Autorzy:
Surowiak, A.
Powiązania:
https://bibliotekanauki.pl/articles/319165.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
liberation efficiency
hard coal
particle size distribution
particle density distribution
stopień uwolnienia
węgiel kamienny
skład ziarnowy
skład densymetryczny
Opis:
The main tool allowing to forecast effects of gravitational beneficiation of hard coals is density analysis. The obtained results of such analysis should show real minerals liberation level in connection with their physical properties. In purpose of calculating mineral phase liberation from hard coal the size and density analysis was performed for raw hard coal which was feed directed to mineral processing. For each obtained size-density fraction its yield and ash contents were determined. The Hall’s separation curve was used in the paper to evaluate liberation efficiency of mineral phase from hard coal. The advantage of this curve is the fact that it is possible to describe it mathematically by means of hyperbolic equation. It was stated that if particle size is lower the liberation level of mineral substance grows.
Podstawowym narzędziem pozwalającym prognozować efekty wzbogacania grawitacyjnego węgli kamiennych jest analiza densymetryczna. W związku z tym otrzymane wyniki takiej analizy powinny odzwierciedlać rzeczywisty stopień uwolnienia minerałów w powiązaniu z ich właściwości fizycznymi. W celu wyliczenia uwolnienia fazy mineralnej z węgla kamiennego wykonano analizę granulometryczną i densymetryczną surowego węgla kamiennego – nadawy kierowanej do przeróbki mechanicznej. W otrzymanych klaso-frakcjach wyliczono wychody oraz oznaczono zawartość popiołu. W artykule wykorzystano krzywą separacji Halla do oceny stopnia uwolnienia frakcji mineralnej z węgla kamiennego. Zaletą krzywej separacji Halla jest to, że można ją opisać w sposób matematyczny przy pomocy równania hiperboli. Stwierdzono, że ze wraz z zmniejszaniem się wielkości ziaren wzrasta stopień uwolnienia substancji mineralnej.
Źródło:
Inżynieria Mineralna; 2013, R. 14, nr 2, 2; 153-158
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for the determination of spatial electron density distribution in great Plasma-Focus devices
Autorzy:
Kasperczuk, A.
Paduch, M.
Pisarczyk, T.
Tomaszewski, K.
Powiązania:
https://bibliotekanauki.pl/articles/147148.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
bremsstrahlung radiation
electron density distribution
frame optical camera
plasma-focus device
plasma radiation intensity
shadowgraphy
Opis:
Determination of the electron density of plasma generated in a great plasma-focus device by means of interferometry is very difficult or sometimes impossible. In order to determine spatial electron density distributions of plasma in a PF-1000 device, a special method was prepared, with the use of plasma images obtained by means of both an optical frame camera and shadowgraphy. Analysis of plasma radiation in the very narrow Äë = 60 Ĺ optical range allowed us to determine the relation between intensity of the plasma radiation and the electron density. It was also shown that the influence of electron temperature on plasma radiation is not large. The presented method allowed us to obtain spatial electron density distributions of plasma (in relative units) in the PF-1000 device. By means of this method a number of important information about the plasma-focus phenomenon was obtained.
Źródło:
Nukleonika; 2002, 47, 1; 23-26
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Xe and Kr bonding abilities in the single crystal oxygen vacancies of the uranium based fuel
Autorzy:
Dąbrowski, L.
Szuta, M.
Powiązania:
https://bibliotekanauki.pl/articles/147880.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
noble gases
chemical bond
UO2 single crystal
valence electron density distribution
atomic force constants
bond energy
crystal lattice
Opis:
The valence electron density distribution of krypton and xenon located in the oxygen vacancy and in its nearest neighbourhood was performed by application of the method “ab initio”. The results are presented on the graphs. The bonding energies of krypton and xenon in the uranium dioxide crystal lattice were calculated. It was found also that krypton and xenon cause a local increase of UO1.75Xe0.25 and UO1.75Kr0.25 unit cell and cause its deformation what is presented in tables. The force constants of krypton and xenon were also assigned what gives evidence about the strong bond of krypton and xenon with the UO1.75Xe0.25 and UO1.75Kr0.25 single crystal lattice. Obtained results are compared with the analogical studies of He atom incorporation into UO2 single crystal lattice.
Źródło:
Nukleonika; 2012, 57, 1; 95-100
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Binary Classification of Heart Failures Using k-NN with Various Distance Metrics
Autorzy:
Udovychenko, Y.
Popov, A.
Chaikovsky, I.
Powiązania:
https://bibliotekanauki.pl/articles/226330.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
magnetocardiography
current density imaging
current density distribution map
k-NN classification
negative Tpeak
heart failure diagnostics
Mahalanobis distance
Cityblock distance
Eucleadian distance
Chebyshev distance
Opis:
Magnetocardiography is a sensitive technique of measuring low magnetic fields generated by heart functioning, which is used for diagnostics of large number of cardiovascular diseases. In this paper, k-nearest neighbor (k-NN) technique is used for binary classification of myocardium current density distribution maps (CDDM) from patients with negative T-peak, male and female patients with microvessels (diffuse) abnormalities and sportsmen, which are compared with normal control subjects. Number of neighbors for k-NN classifier was selected to obtain highest classification characteristics. Specificity, accuracy, precision and sensitivity of classification as functions of number of neighbors in k-NN are obtained for classification with several distance measures: Mahalanobis, Cityblock, Eucleadian and Chebyshev. Increase of the accuracy of classification for all groups up to 10% was obtained using Cityblock distance metric in binary k-NN classifier with 19 - 27 neighbors, comparing to other metrics. Obtained results are acceptable for further patient’s state evaluation.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 4; 339-344
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania rozkładu gęstości elektronowej w kryształach, czyli jak zobaczyć szczegóły struktury elektronowej cząsteczek
Electron density distribution in crystals or how to see the details of the electronic structure of molecules
Autorzy:
Kubicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/171566.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
rozkład gęstości elektronowej
model multipolowy
oddziaływania międzycząsteczkowe
pochodne 4-nitroimidazolu
electron density distribution
multipolar model
intermolecular interactions
4-nitroimidazole derivatives
Opis:
X-ray structural analysis might be regarded as a method of visualizing molecules as they appear in the crystals. The model, which is conventionally and universally used in this method, the Independent Atom Model (IAM) assumes that the electron density distribution, which scatters the X-rays is built of the spherically-symmetrical, neutral atoms. This model is responsible for the unprecedented success of X-ray structural analysis, which reflects in about one million crystal structures (i.e. the sets coordinates of the atoms constituting the molecules) deposited in the various databanks (cf. Fig. 1), and in the speed and accuracy which the method has reached. In principle, in few hours one can get the complete information about the crystal structure. But this success is accompanied by negligence of the scientific virtue hidden beyond the IAM. In fact, it was known from the very beginning of the X-ray diffraction studies by von Laue and Braggs, that some fine details of the electron density distribution should be available. The technological advance (four-circle diffractometers, powerful X-ray sources, fast computers etc.) caused that in 1960’s the time was ripe for the development of the experimental studies of details of electron density distribution in the crystals, beyond the IAM. The early experiments by Coppens and co-workers proved that this information – about the electron density transferred to the covalent bonds, lone pairs, even intermolecular interactions – can actually be obtained and analyzed (Fig. 2). The need for the model which could be used in the least-squares procedure led to the formulation of so-called pseudoatom models, including the most popular till now, Hansen-Coppens model (eq. 2) in which the aspherical part is described in terms of real spherical harmonics. In this paper, the basics of the electron density studies is described in some detail, including the step-by-step description of a typical procedure from the experiment to the final steps of refinement. An example of the analysis of the high-resolution structure of 1,2-dimethyl-4-nitro-5-morpholine-imidazole hydrate is used to show an application of this method in studying the intermolecular interactions, including weak C-H···O and C-H···N hydrogen bonds. It is shown that the multipolar model is able to deliver more informations than the promolecular model with spherically symmetrical electron distributions.
Źródło:
Wiadomości Chemiczne; 2014, 68, 5-6; 403-427
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Symulacyjna analiza losowych błędów estymacji czasu opóźnienia przy zastosowaniu metody korelacyjnej i fazowej
Simulation analysis of random errors of time delay estimation by cross-correlation and phase methods
Autorzy:
Hanus, R.
Petryka, L.
Zych, M.
Powiązania:
https://bibliotekanauki.pl/articles/157098.pdf
Data publikacji:
2008
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
estymacja czasu opóźnienia
funkcja korelacji wzajemnej
faza wzajemnej gęstości widmowej mocy
błędy statystyczne
time delay estimation
cross-correlation analysis
phase of power density distribution
statistical errors
Opis:
W artykule przedstawiono wyniki analizy porównawczej losowych błędów estymacji czasu opóźnienia otrzymanego z funkcji korelacji wzajemnej i fazy wzajemnej gęstości widmowej mocy. Przeprowadzone symulacje wykazały, że dla małych wartości stosunku sygnał/szum (SNR) mniejsze wartości błędów uzyskuje się dla metody korelacyjnej. Metoda fazowa jest natomiast bardziej efektywna dla dużych wartości SNR, a jej zaletą jest możliwość wyznaczenia opóźnienia dla wybranych harmonicznych.
The paper presents results of the comparative analysis of random errors of the time delay estimation (TDE) by means of the cross-correlation analysis and the phase of power density distribution. The simulations performed show that for the low level of signal-to-noise-ratio (SNR) the statistical errors of TDE obtained from the cross-correlation analysis are smaller than those from the phase method. However, the latter one is more efficient for higher SNR than the cross- correlation and can be applied to any selected harmonics.
Źródło:
Pomiary Automatyka Kontrola; 2008, R. 54, nr 12, 12; 860-862
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetics of the continuous reaction crystallization of barium sulphate in BaCl2 - (NH4)2SO4 - NaCl - H2O system - neural network model
Autorzy:
Piotrowski, K.
Koralewska, J.
Wierzbowska, B.
Matynia, A.
Powiązania:
https://bibliotekanauki.pl/articles/778848.pdf
Data publikacji:
2009
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
siarczan baru
jony sodu
sole pohartownicze
hartowanie stali
chlorek baru
kinetyka krystalizacji
barium sulphate
sodium ions
used quenching salts
steel hardening
barium chloride
reaction crystallization kinetics
population density distribution
chemical neutralization
solid waste utilization
neural network model
Opis:
One of the main toxic components of post quenching salts formed in large quantities during steel hardening processes is BaCl2. This dangerous ingredient can be chemically neutralized after dissolution in water by means of reaction crystallization with solid ammonium sulphate (NH4)2SO4. The resulting size distribution of the ecologically harmless crystalline product - BaSO4 - is an important criteria deciding about its further applicability. Presence of a second component of binary quenching salt mixture (BaCl2-NaCl) in water solution, NaCl, influences the reaction-crystallization process kinetics affecting the resulting product properties. The experimental 39 input-output data vectors containing the information about the continuous reaction crystallization in BaCl2 - (NH4)2SO4 - NaCl - H2O system ([BaCl2]RM = 10-24 mass %, [NaCl]RM = 0-12 mass %, T = 305-348 K and τ = 900-9000 s) created the database for the neural network training and validation. The applicability of diversified network configurations, neuron types and training strategies were verified. An optimal network structure was used for the process modeling.
Źródło:
Polish Journal of Chemical Technology; 2009, 11, 4; 13-19
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proofs of the normalization of the function of the thickness classes one-dimensional distributions normal
Dowody unormowania funkcji gęstości klasy jednowymiarowych rozkładów normalnych
Autorzy:
Wagner, Wiesław
Parys, Dariusz
Stępień, Lechosław
Powiązania:
https://bibliotekanauki.pl/articles/906301.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
normal distribution
normalization of density function
Opis:
Jednowymiarowy dwuparametrowy rozkład normalny należy do podstawowych rozkładów prawdopodobieństwa w statystyce. W ostatnich latach powstało wiele jego uogólnionych wersji, uwzględniających parametry asymetrii i kurtozy. Tworzą one klasę rozkładów normalnych «-parametrowych, odpowiednio z parametrami: m = 1 położenia (przesunięcia), m = 2 - położenia i zmienności (skali), m = 3 - położenia, zmienności i skośności oraz m = 4 - położenia, zmienności, skośności i spłaszczenia. W pracy podajemy 7 wybranych jednowymiarowych rozkładów prawdopodobieństwa z klasy rozkładów normalnych. Dla nich wymieniono funkcje gęstości oraz przedstawiono dowody unormowania pokazując, iż całka po obszarze określoności tych funkcji jest równa jeden.
One-dimensional two parameters the normal distribution assorts basic probability distributions in the statistics, in last years into being many generalized versions, taking into account parameters of the asymmetry and the kurtosis. They there create the class of normal distributions «-parameter, properly with parameters, m = 1 - positions (shifts), m — 2 — positions and variations (scale), m = 3 - positions, variations and skewness and m = 4 - positions, variations, skewnesses and kurtosis. On the job we give 7 chosen one-dimensional probability distributions from the class of normal distributions. For them one mentioned functions of the thickness and one averred normalizations to show, that the integral after area of the determinates of these functions is equal one.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2009, 228
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surrogate synthesis of excitation systems for frame tangential eddy current probes
Autorzy:
Halchenko, Volodymir Yakovych
Trembovetska, Ruslana Volodymyrivna
Tychkov, Volodymir Volodymyrovych
Powiązania:
https://bibliotekanauki.pl/articles/1955174.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
additive neural network regression
eddy current probe
stochastic optimization algorithm
surrogate optimization
uniform eddy current density distribution
velocity effect
addytywna regresja sieci neuronowej
sonda prądów wirowych
algorytm optymalizacji stochastycznej
optymalizacja zastępcza
równomierny rozkład gęstości prądów wirowych
efekt prędkości
Opis:
Existing scientific studies devoted to the design of eddy-current probes with a priori given configuration of the electromagnetic excitation field, which provide a uniform eddy current density distribution, consider a wide class of such, but are limited to the case when the probe is stationary relative to the testing object. Therefore, the actual problem is the synthesis of moving tangential eddy current probes with a frame excitation system that provides a uniform eddy current density distribution in the testing object, the solution of which is proposed in this study. A mathematical method for nonlinear surrogate synthesis of excitation systems for frame moving tangential surface eddy current probes, which implements a uniform eddy current density distribution of the testing zone object, is proposed. A metamodel of the volumetric structure of the excitation system of the frame tangential eddy current probe, applied in the process of surrogate optimal parametric synthesis, has been created. The examples of nonlinear synthesis of excitation systems using modern metaheuristic stochastic algorithms for finding the global extremum are considered. The numerical results of the obtained solutions of the problems are presented. The efficiency of the synthesized structures of excitation systems in comparison with classical analogs is shown on the graphs of the eddy current density distribution on the object surface in the testing zone.
Źródło:
Archives of Electrical Engineering; 2021, 70, 4; 743-757
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On normal numbers mod $2$
Autorzy:
Ahn, Youngho
Choe, Geon
Powiązania:
https://bibliotekanauki.pl/articles/1396059.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
coboundary
metric density
normal number
uniform distribution
Opis:
It is proved that a real-valued function $f(x)=\exp(\pi i \chi_I(x))$, where I is an interval contained in [0,1), is not of the form $f(x)=\overline{q(2x)}q(x)$ with |q(x)|=1 a.e. if I has dyadic endpoints. A relation of this result to the uniform distribution mod 2 is also shown.
Źródło:
Colloquium Mathematicum; 1998, 76, 2; 161-170
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the distribution and density of measurement points in terms of terrain modelling
Autorzy:
Gradka, R.
Powiązania:
https://bibliotekanauki.pl/articles/100653.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie
Tematy:
DTM
distribution
density
GRID
ordinary kriging
dystrybucja
gęstość
Opis:
For the implementation of direct measurements, proper understanding of the existing relationships and spatial variability, and at later stages, for obtaining reliable results of geostatistical analysis, adequate planning network measurement and correct placement of, and/or the evaluation of the number of measurement points in the measurement network are not the only necessary conditions. Another key prerequisite is choosing the right model for creating a DTM, which depends on the shape of the terrain. Correct spatial sampling should provide much information on the spatial distribution of the studied variable in an area, at minimal cost and with minimal effort. Faithful reproduction of the land surface that reflects any of the characteristics of the environment is not possible through DTM, due to a number of restrictions, manifesting themselves in the form and size of the data set; due to time and economic constraints; and also because the full complexity of the terrain’s surface cannot be measured or expressed. The present work undertakes to analyse the density and distribution of measuring points on four areas that have specific characteristics in common, yet they remain different in terms of surfaces, height differences, as well as their complexity. After selecting the research areas, these were designed and laid out in a grid with the shape of rectangles that were similar in structure to the GRID model. The data were analysed using geostatistical interpolation by ordinary kriging, in order to conduct a proper analysis of the distribution and density of the measuring points, to calculate the surface properties of a particular point, and in order to attempt to reduce the workload and cost factor.
Źródło:
Geomatics, Landmanagement and Landscape; 2017, 3; 35-45
2300-1496
Pojawia się w:
Geomatics, Landmanagement and Landscape
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soil physical properties affected by biochar addition at different plant phaenological phases. Part II
Autorzy:
Mako, A.
Barna, G.
Horel, A.
Powiązania:
https://bibliotekanauki.pl/articles/2082863.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
biochar
aggregate size distribution
hydraulic
conductivity
bulk density
Opis:
A great emphasis has been placed on biochar addition to soils to improve its physical, chemical, and biological properties in recent times in order to achieve improved crop growth and yields. The present study explored to soil physical changes through different plant growth stages caused by biochar addition to silt loam soil in a pot-experiment. Our research focused on changes in soil bulk density, aggregate size distribution, and saturated hydraulic conductivity. The soils were amended with different amounts of biochars (control with 0, BC0.5 with 0.5%, BC2.5 with 2.5%, and BC5.0 with 5.0% biochar, by weight). Capsicum annuum L. were planted at a two-four leaf stage. Soil samples were taken at 6, 10 and 12 weeks after planting. The biochar amendment resulted in a significant decrease in soil bulk density values. Soil saturated hydraulic conductivity values ranged between 5.5 and 7.9 times higher for all treatments compared to the controls.
Źródło:
International Agrophysics; 2020, 34, 1; 1-7
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The variability of spatial distribution and density of fish in the Klimkówka dam reservoir
Autorzy:
Świerzowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/332221.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
Klimkówka Dam Reservoir
spatial distribution
density of fish
Opis:
The Klimkówka Dam Reservoir is situated on the Ropa River in southern Poland. The surface area of the reservoir is about 306 ha and its capacity is 43.5 hm3. Acoustic surveys were conducted both in the daytime and at night using a SIMRAD EY-500 split beam 120kHz echo sounder. Maps of the spatial distribution and density of fish were drawn up, and the fish species structure, size, number and biomass were estimated based on acoustic surveys and supervised net catches. The highest fish density at night occurred in the river tributary zones (836 fish/ha). In this area at night fish density was twice as high as in the central region of the reservoir. The density figure for the whole reservoir was 638 fish/ha and was 1.4 limes higher than that in the Solina Reservoir and from ten- to twenty-fold lower than in several other studied lakes. Fish catches performed with pelagic trawIs and net sets revealed the presence of nine fish species. Lake and river trout species which had been introduced to the reservoir were not noted. The fish biomass was estimated to be 11.5 tons, or 44.4 kg/ha, and was from three to 14 times lower in comparison to the estimated figure in several other lakes.
Źródło:
Hydroacoustics; 2003, 6; 69-78
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution of gas molecules by their temperatures
Autorzy:
Golovkin, Boris Georgievich
Powiązania:
https://bibliotekanauki.pl/articles/1030475.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Clapeyron equation
Maxwell distribution
distribution of molecules by temperatures
gas density
gas pressure
Opis:
A formula is derived for the distribution of gas molecules over their temperatures depending on the total temperature of the gas. Formulas are proposed for the distribution of velocities and kinetic energies of gas molecules depending on the pressure and density of the gas. It is shown that these formulas are equivalent to the formulas of the corresponding Maxwell distributions, which depend only on temperature. A formula is derived for the distribution of the mean free paths of gas molecules depending only on the gas density. An example of calculating the distribution of gas molecules by their temperatures is given.
Źródło:
World Scientific News; 2020, 144; 89-102
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterising root density of peach trees in a semi-arid Chernozem to increase plant density
Autorzy:
Paltineanu, C.
Septar, L.
Gavat, C.
Chitu, E.
Oprita, A.
Moale, C.
Calciu, I.
Vizitiu, O.
Lamureanu, G.
Powiązania:
https://bibliotekanauki.pl/articles/24890.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
root density
peach tree
black earth
plant density
root distribution
soil property
trench method
Źródło:
International Agrophysics; 2016, 30, 1
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shifted up cosine function as unconventional model of probability distribution
Autorzy:
Warsza, Z. L.
Korczynski, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/384539.pdf
Data publikacji:
2010
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
probability density function PDF
cosines approximation of normal distribution
Opis:
The shifted up one period of cosine function with field under it normalized to 1 is proposed to be use as the un conventional model of probability density function (PDF). It could also approximate Normal probability distribution in the range š 2.5 standard deviation with accuracy of about š0.02, which is fully acceptable in the evaluation of measurement uncertainty. In this paper the properties of the above cosine based PDF are considered. The possibility of its applications in the routine data assessment and in virtual instruments with automatic uncertainty calcula tions is recommended.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2010, 4, 1; 49-55
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution and relative density of trees species in Kainji Lake National Park, Nigeria
Autorzy:
Akande, O. A.
Ahmad, Y. A.
Shuaib, A. B.
Jeje, C. A.
Powiązania:
https://bibliotekanauki.pl/articles/1077871.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Distribution
Kainji Lake National Park
relative density
species
trees
Opis:
The importance of trees in the environment cannot be overemphasized. This present study, therefore, deals with the distribution and relative density of trees species in Kainji Lake National Park. Data were collected using plot sampling techniques. Therein, a 50 by 50 m2 plot was randomly laid. Within each sample plot, data on all trees ≥ 10 cm in diameter at breast height were enumerated. The data were analyzed using descriptive statistics. The result shows that different types of plants species were enumerated in the selected plots. This included six families of trees: Fabiaceae, Caesalpiniaceae, Rubiaceae, Maliaceae, Annonaceae and Mimosaceae. The percentage score of tree species in the four plots reveals that Afzelia africana recorded the highest with a total number of 60 species, followed by Detarium macrocarpium with 47 species, while Anogeissus leiocarpus and Azadirachta indica recorded 31 and 17 species, respectively. Gardenia aqualla was the least species recorded. The density and relative density of Afzelia africana recorded the highest, with 1.2ha and 26.9%, followed by Detarium microcarpiuum with 0.94ha and 21.1%, respectively, while Gardenia aqualla was the least with 0.02 ha and 0.4%. In terms of mean height, Daniela oliveri recorded the highest, with 28.1m, followed by Afzelia africana with 21.8%, while Azadirachta indica was the least with 5.8%. The mean DBH of Entada africana and Anogeissus leiocarpus recorded was 28.7cm and 28.1cm, while Prosopis africana and Accacia gournmaensis recorded 14.0 and 13.4, respectively, which were the least. The Types of wild animal species that are associated with the tree species includes Baboon, Kob, Grim duiker, Francolin, Patas monkey etc. Relative abundance of the animal species shows that Papio anubis recorded the highest with 40.5 individuals, while Erythrocebus patas recorded the least with 2.5 individuals.
Źródło:
World News of Natural Sciences; 2019, 22; 52-61
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical downscaling of probability density function of daily precipitation on the Polish coast
Autorzy:
Wójcik, R.
Pilarski, M.
Miętus, M.
Powiązania:
https://bibliotekanauki.pl/articles/108542.pdf
Data publikacji:
2014
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
statistical downscaling
canonical correlation
precipitation totals
probability density function
gamma distribution
Opis:
The aim of this study was to recognize the possibility of downscaling probability density function (PDF) of daily precipitation by means of canonical correlation analysis (CCA). Sea level pressure (SLP) over Europe and the North Atlantic was used as a predictor. A skilful statistical model could be used to generate projections of future changes of precipitation PDF driven by GCM (General Circulation Model) simulations. Daily precipitation totals from 8 stations located on the Polish coast of the Baltic Sea covering the period 1961-2010 were used to estimate the gamma distribution parameters, and only wet days (i.e. ≥0.1mm) were taken in the analysis. The results of the Kolmogorov-Smirnov test and comparison of empirical and theoretical (gamma-distributed) quantiles proved that gamma distribution gives a reliable description of daily precipitation totals. The validation of CCA models applied to gamma parameters revealed that the reliable reconstruction of precipitation PDF is possible only for average long-term conditions. In the case of individual months/seasons the agreement between empirical and reconstructed quantiles is poor. This study shows the potential of modelling of precipitation PDF, however efforts should be made to improve model performance by establishing more reliable links between regional forcing and the variability of the gamma parameters.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2014, 2, 1; 27-36
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimating normal density and normal distribution function: is Kolmogorovs estimator admissible?
Autorzy:
Rukhin, Andrew
Powiązania:
https://bibliotekanauki.pl/articles/1340688.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
point estimation
normal density
Bayes estimator
quadratic loss
admissibility
normal distribution function
Opis:
The statistical estimation problem of the normal distribution function and of the density at a point is considered. The traditional unbiased estimators are shown to have Bayes nature and admissibility of related generalized Bayes procedures is proved. Also inadmissibility of the unbiased density estimator is demonstrated.
Źródło:
Applicationes Mathematicae; 1993-1995, 22, 1; 103-115
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Verification of flotation kinetics model for triangular distribution of density function of flotability of coal particles
Weryfikacja modelu kinetyki flotacji dla trójkątnego rozkładu funkcji gęstości flotowalności ziaren węgla
Autorzy:
Kalinowski, K.
Kaula, R.
Powiązania:
https://bibliotekanauki.pl/articles/218720.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
modele kinetyki flotacji
współczynnik prędkości flotacji
funkcja gęstości rozkładu frakcji
flotowniki przemysłowe
models of the flotation kinetics
coefficient of flotation velocity
distribution density function of the fraction
industrial flotation machine
Opis:
Parameters of flotation kinetics model with a gamma and a triangular distribution have been determined based on the batch coal flotation experiments. Analyses were carried out at different values of the intensity of aeration air. The results of example analyses are presented in tables and graphs form. It follows from the carried out study on the mathematical models of flotability coefficient distribution of particles of examined coal samples that the triangular distribution model is statistical equivalent to the gamma flotability distribution. The assumption of the triangular distribution enables determination of the density function of distribution of fraction in the industrial flotation machines. Knowledge of this function will allow better evaluation of the phenomena occurring in the process of enrichment. It may be one of the basic information used in the supervisory control system.
Na podstawie badań eksperymentalnych flotacji cyklicznej węgla wyznaczono parametry modelu kinetyki flotacji z rozkładem gamma i trójkątnym. Analizy przeprowadzono przy różnych wartościach natężenia powietrza do aeracji. Wyniki przykładowych analiz przedstawiono tabelarycznie i w postaci wykresów. Z przeprowadzonych badań nad modelami matematycznymi rozkładu współczynnika flotowalności ziaren badanych próbek węgla wynika, że model o rozkładzie trójkątnym statystyczne jest równoważny rozkładowi flotowalności gamma. Przyjęcie rozkładu trójkątnego umożliwi wyznaczenie funkcji gęstości rozkładu frakcji we flotownikach przemysłowych. Znajomość tej funkcji pozwoli na lepszą ocenę zjawisk zachodzących w procesie wzbogacania. Może stanowić jedną z podstawowych informacji wykorzystywanych w nadrzędnym systemie sterowania.
Źródło:
Archives of Mining Sciences; 2013, 58, 4; 1279-1287
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropic charged stars with quadratic equation state
Autorzy:
Malaver, Manuel
Powiązania:
https://bibliotekanauki.pl/articles/1178297.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Anisotropic charged matter distribution; compact stellar objects; energy density; quadratic equation of state
Opis:
In this paper, we present a new model of static spherically symmetric relativistic compact stellar objects with anisotropic charged matter distribution and quadratic equation of state together with a prescribed form for the gravitational potential Z used by Bhar and Murad (2016). A graphical analysis of the physical properties indicate indicates that the new model well behaved and not admit singularities in the matter and the charge density.
Źródło:
World Scientific News; 2017, 86, 3; 333-344
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
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