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Tytuł:
An analytical model to predict water retention curves for granular materials using the grain-size distribution curve
Autorzy:
Bouacida, Linda
Feia, Sadok
Denine, Sid Ali
Della, Noureddine
Powiązania:
https://bibliotekanauki.pl/articles/2172891.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sand
mean grain size
mean pore size
density index
model
pore size distribution
water retention curve
Opis:
The present work aims to propose a new analytical model intended to predict the water retention curves for granular materials based on data from tensiometric tests. Different analytical models have been used for the evaluation of soil water retention curves so far. It should be noted that the proposed model considers only one criterion in the selection of soils. This criterion is the physical property of particle distribution curve that can be used to determine the values of D50 and CU. In this study, the pore-access size distribution is investigated considering the effect of the coefficient of uniformity of sandy soils that were prepared with different density indexes (0.5, 0.7, and 0.9). Moreover, the proposed model equation is based on the physical properties of soil. This equation made it possible to describe the water retention curve and to estimate the pore-access size distribution without performing any experimental tests. The findings allowed asserting that the uniformity of the particle size curves corresponds to a good uniformity of the pore-access size distribution. In addition, it was revealed that the suction increased as the density index went up, which matches well with the experimental data. Moreover, it may clearly be noted that the distinctive retention properties of unsaturated soils can be observed on the above-mentioned curves. Further, it was found that the ratio of the grain size over the pore-access size increased as the uniformity coefficient augmented.
Źródło:
Studia Geotechnica et Mechanica; 2022, 44, 4; 354--369
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Derivation of Equations for a Size Distribution of Spherical Particles in Non-Transparent Materials
Autorzy:
Gurgul, Daniel
Burbelko, Andriy
Wiktor, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2056033.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
planimetric analysis
linear analysis
estimation of diameter sizes distribution
probability density function
analiza planimetryczna
analiza liniowa
szacowanie rozkładu wielkości średnic
funkcja gęstości prawdopodobieństwa
Opis:
This paper presents a new proposition on how to derive mathematical formulas that describe an unknown Probability Density Function (PDF3) of the spherical radii (r3) of particles randomly placed in non-transparent materials. We have presented two attempts here, both of which are based on data collected from a random planar cross-section passed through space containing three-dimensional nodules. The first attempt uses a Probability Density Function (PDF2) the form of which is experimentally obtained on the basis of a set containing two-dimensional radii (r2). These radii are produced by an intersection of the space by a random plane. In turn, the second solution also uses an experimentally obtained Probability Density Function (PDF1). But the form of PDF1 has been created on the basis of a set containing chord lengths collected from a cross-section. The most important finding presented in this paper is the conclusion that if the PDF1 has proportional scopes, the PDF3 must have a constant value in these scopes. This fact allows stating that there are no nodules in the sample space that have particular radii belonging to the proportional ranges the PDF1.
Źródło:
Journal of Casting & Materials Engineering; 2021, 5, 4; 53--60
2543-9901
Pojawia się w:
Journal of Casting & Materials Engineering
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:
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:
Estimating the population mean using a continuous sampling design dependent on an auxiliary variable
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/1059051.pdf
Data publikacji:
2020-12-04
Wydawca:
Główny Urząd Statystyczny
Tematy:
continuous sampling design
Horvits-Thompson estimator
inclusion density
sampling scheme
bivariate gamma distribution
ratio estimator
Opis:
Continuous distribution of variables under study and auxiliary variables are considered. The purpose of the paper is to estimate the mean of the variable under study using a sampling design which is dependent on the observation of a continuous auxiliary variable in the whole population. Auxiliary variable values observed in this population allow to estimate the inclusion density function of the sampling design. The variance of the continuous version of the Horvitz-Thompson estimator under the proposed sampling design is compared with the variance of the mean of a simple random sample. The accuracy of the estimation strategies is analysed by means of simulation experiments.
Źródło:
Statistics in Transition new series; 2020, 21, 5; 1-16
1234-7655
Pojawia się w:
Statistics in Transition new series
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:
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:
Gravitational tomography as an inverse problem in the field theory
Tomografia grawitacyjna jako problem odwrotny w teorii pola
Autorzy:
Bednarek, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/1837619.pdf
Data publikacji:
2019
Wydawca:
Łódzkie Towarzystwo Naukowe
Tematy:
gravity
tomography
acceleration
spatial distribution
density
computation
grawitacja
tomografia
przyspieszenie
rozkład przestrzenny
gęstość
obliczanie
Opis:
At the beginning of the article, the simple and inverse problem in field theory is described and the term tomography is explained. There are also examples of the use of gravitational omography and its significance in Earth sciences. The main purpose of the article is to present two practical calculation procedures intended to determine the spatial distribution of density in objects with spherical-symmetrical mass distribution. In the first procedure, the object is divided into concentric spheres of equal thickness. In the second procedure, the object is divided into concentric spheres of equal volume, which provides more precise information about the distribution of density in the outer layers of the object. The density values are obtained by solving a system of linear equations with introduced results of measurements of gravity acceleration performed with a gravimeter outside the object.
Na wstępie artykułu opisano, na czym polega problem prosty i odwrotny w teorii pola oraz wyjaśniono znaczenie terminu tomografia. Podano też przykłady zastosowania tomografii grawitacyjnej i jej znaczenie w naukach o Ziemi. Głównym celem artykułu jest przedstawienie dwóch praktycznych procedur obliczeniowych, przeznaczonych do wyznaczania rozkładu przestrzennego gęstości w obiektach o kulisto-symetrycznym rozkładzie masy. W pierwszej procedurze obiekt jest dzielony na współśrodkowe sfery o równej grubości. W drugiej procedurze następuje podział l obiektu na współśrodkowe sfery o równej objętości, co daje dokładniejszą informację o rozkładzie gęstości w zewnętrznych warstwach obiektu. Wartości gęstości są otrzymywane w wyniku rozwiązania układu równań  liniowych, do którego zostały  wprowadzone wyniki pomiarów przyspieszenia siły ciężkości, wykonane grawimetrem na zewnątrz obiektu.
Źródło:
Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations; 2019, 69, 1; 117-128
1895-7838
2450-9329
Pojawia się w:
Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Injury prediction models for onshore road network development
Autorzy:
Kustra, Wojciech
Żukowska, Joanna
Budzyński, Marcin
Jamroz, Kazimierz
Powiązania:
https://bibliotekanauki.pl/articles/259016.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
road safety
Polish national roads
density of injuries
log logistic and gamma distribution
risk management
Opis:
Integrating different modes of transport (road, rail, air and water) is important for port cities. To accommodate this need, new transport hubs must be built such as airports or sea ports. If ports are to grow, they must be accessible, a feature which is best achieved by building new roads, including fast roads. Poland must develop a network of fast roads that will provide good access to ports. What is equally important is to upgrade the network of national roads to complement fast roads. A key criterion in this case is to ensure that the roads are efficient to minimise time lost for road users and safe. With safety standards and safety management practices varying vastly across the EU, Directive 2008/96/EC of the European Parliament and of the Council was a way to ensure that countries follow procedures for assessing the impact of road projects on road safety and conduct road safety audits, road safety management and road safety inspections. The main goal of the research was to build mathematical models to combine road safety measures, i.e. injury density (DI) and accident density (DA), with road and traffic factors on longer sections, all based on risk analysis. The practical objective is to use these models to develop tools for assessing how new road projects will impact road safety. Because previous research on models to help estimate injuries (I) or injury density (DI) on long sections was scarce, the authors addressed that problem in their work. The idea goes back to how Poland is introducing procedures for assessing the effects of infrastructure on safety and developing a method to estimate accident indicators to support economic analysis for new roads, a solution applied in JASPERS. Another reason for the research was Poland’s insufficient and ineffective pool of road safety management tools in Poland. The paper presents analyses of several models which achieved satisfactory results. They are consistent with the work of other researchers and the outcomes of previous research conducted by the authors. The authors built the models based on a segmentation of national roads into sections from 10 to 50 km, making sure that they feature consistent cross-sections and average daily traffic volumes. Models were built based on the method described by Jamroz (Jamroz, 2011). Using the available road traffic volume data, each section was assigned variables defining geometric and traffic features. Based on studies conducted on road sections, the variables were either averaged over the entire length of the section or calculated as a percentage of the variable occurring over the entire length: related to traffic volume, roadside environment or cross section.
Źródło:
Polish Maritime Research; 2019, 2; 93-103
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Optimal structure of the connections of a flotation machine with three cells
Optymalna struktura połączeń maszyny flotacyjnej z trzema komorami
Autorzy:
Kaula, R.
Kalinowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/216099.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
współczynnik prędkości flotacji
funkcja gęstości
flotowalność ziaren węgla
charakterystyka statyczna
flotownik wielokomorowy
struktura optymalna
flotownik trójkomorowy
flotation velocity coefficient
distribution density function
coal particles flotability
static characteristics
flow flotation machine
optimal structure
three cells flotation machine
Opis:
Flotation enrichment is a complex process due to the influence of many factors on the course of this process. In macroscopic terms, it is assumed that the quantity that takes into account the influence of all important factors on the enrichment process is the flotation velocity coefficient k. In industrial practice the flotation process is followed by heterogeneous material in terms of flotation properties. Therefore, the flotation velocity coefficient k will be characterized by a certain distribution. Thus, the distribution can be described as the function of the density distribution of the particles flotability f(k). Characteristics of this type are used in the design and optimization of flotation technological circuits. The paper presents a three cells flotation machine with a specific structure of connections of individual cells and the methods of selecting their parameters. The proposed circuit of the three cells flotation machine is characterized by a different connection structure and the specific parameters of each cell than the serial (cell-to-cell) flotation machine. The defined structure of connections between the cells and proper selection of their parameters ensures the maximum slope of the “separation characteristics” of the machine for the velocity coefficient k. Conducting the process of mineral enrichment in the proposed system enables the most efficient separation of the useful feed components. [...]
Wzbogacanie flotacyjne jest procesem złożonym ze względu na wpływ wielu czynników na przebieg tego procesu. W ujęciu makroskopowym przyjmuje się, że wielkością która uwzględnia wpływ wszystkich istotnych czynników na proces wzbogacania, jest współczynnik prędkości flotacji k ziaren. W praktyce przemysłowej do procesu flotacji kieruje się materiał niejednorodny pod względem właściwości flotacyjnych. W związku z tym współczynnik prędkości flotacji k będzie się charakteryzował pewnym rozkładem. Nadawę można zatem opisać funkcją gęstości rozkładu flotowalności ziaren f(k). Charakterystyki tego typu stosuje się przy projektowaniu i optymalizacji układów technologicznych flotacji. W artykule przedstawiono maszynę flotacyjną trójkomorową o określonej strukturze połączeń poszczególnych komór i sposobie doboru ich parametrów. Proponowany układ połączeń maszyny flotacyjnej trójkomorowej charakteryzuje się inną od szeregowej strukturą połączeń oraz ściśle określonymi parametrami każdej komory. Zdefiniowany sposób połączeń komór oraz odpowiedni dobór ich parametrów zapewnia maksymalne nachylenie charakterystyki rozdziału maszyny dla współczynnika prędkości k rozdziału. Prowadzenie procesu wzbogacania, w proponowanym układzie, umożliwia najdokładniejszy rozdział składników użytecznych nadawy. [...]
Źródło:
Gospodarka Surowcami Mineralnymi; 2018, 34, 1; 53-68
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
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:
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
Tytuł:
Model symulacyjny gęstościomierza radiometrycznego
Simulation model of a radiometric density meter
Autorzy:
Joostberens, J.
Powiązania:
https://bibliotekanauki.pl/articles/113560.pdf
Data publikacji:
2017
Wydawca:
STE GROUP
Tematy:
gęstościomierz radiometryczny
rozkład Poissona
licznik
cyfrowy filtr dolnoprzepustowy
radiometric density meter
Poisson distribution
counter
low-pass digital filter
Opis:
Gęstościomierze radiometryczne znajdują zastosowanie w układach monitoringu i sterowania różnych procesów technologicznych, w tym również procesów przeróbki węgla kamiennego takich jak: wzbogacanie w cieczy ciężkiej, wzbogacanie w osadzarce, flotacja węgla. Gęstościomierze te działają na zasadzie absorpcji promieniowania gamma. Głowica pomiarowa gęstościomierza składa się ze źródła promieniowania oraz detektora, zwykle w postaci licznika scyntylacyjnego. Sygnał z detektora promieniowania jest ciągiem impulsów, który jest sygnałem stochastycznym o rozkładzie czasowym Poissona. Impulsy te zliczane są często za pomocą licznika impulsów, stanowiącego rodzaj filtru dolnoprzepustowego. Zależność pomiędzy mierzoną średnią wartością gęstości ośrodka, a średnią częstością zliczanych impulsów ma teoretycznie charakter wykładniczy. W artykule przedstawiono model symulacyjny gęstościomierza radiometrycznego. Opisano metodę pomiarową oraz podano równania modelu gęstościomierza. Przedstawiono również przykładowe wyniki badań symulacyjnych w formie graficznej.
Radiometric density meters are widely used in the industry to monitor different technological processes also in coal preparation such as: Heavy-media separation, Jigging, Flotation. Operation of the radiometric density meters is based on the method of gamma radiation absorption. The measuring head of the radiometric density meter consists of a radiation source and a detector usually in the form of a scintillation counter. The output signal from the detector is sequence of pulses which is always a stochastic signal with Poisson distribution. These pulses are often counted by a counter being a kind of a low-pass digital filter. The relation between the measured medium density and the mean intensity of registered pulses is theoretically exponential. In the paper there has been presented a simulation model of the radiometric density meter. There have been described the measurement method and given densitometer model equations. Example simulation results have also been presented in a graphic form.
Źródło:
Systemy Wspomagania w Inżynierii Produkcji; 2017, 6, 2; 126-134
2391-9361
Pojawia się w:
Systemy Wspomagania w Inżynierii Produkcji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena przydatności wybranych funkcji do modelowania rozkładu pierśnic w drzewostanach olszy czarnej (Alnus glutinosa (L.) Gaertn.)
Evaluation of usefulness of selected functions for modeling distribution of breast height diameter in black alder stands (Alnus glutinosa (L.) Gaertn.)
Autorzy:
Orzeł, S.
Pogoda, P.
Ochał, W.
Powiązania:
https://bibliotekanauki.pl/articles/988989.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewostany olszowe
struktura grubosci
olsza czarna
Alnus glutinosa
piersnice drzew
rozklad piersnic
rozklad teoretyczny
aproksymacja
modelowanie
funkcja gestosci prawdopodobienstwa
test Kolmogorowa-Smirnowa
diameter at breast height
diameter distribution
probability density function
kolmogorov−smirnov test
Opis:
We evaluated the usefulness of ten theoretical probability density functions for the approximation of the breast height diameter distributions in managed alder stands growing in the western part of the Sandomierz Basin (southern Poland). The study material consisted of measurement results for 22,530 alders obtained for 844 circular sample plots, established in 163 stands aged 6−89. In the area of particular stands, from 2 to 10 age−dependent circular sample plots sized 0.01−0.10 ha were systematically arranged. We evaluated the following theoretical probability distributions: normal (N), double normal (P−N), Johnson SB (J), Weibull (W), beta (B), Burr (Bu), gamma (G), log−normal (L−N), log−logistic (L−L) and Birnbaum−Saunders (B−S). Additionally the usefulness of the W, B, Bu, G, L−N, L−L and B−S distributions with omitted location parameter was tested. The goodness−of−fit of each probability density function was assessed based on the Kolmogorov−Smirnov statistic, the root mean square error and ranks established on their basis. It was found that DBH distribution of majority stands is characterized by right−sided asymmetry and negative kurtosis. It was showed that the best distribution for the breast height diameter structure approximation of alder stands is the Johnson SB (J) distribution. To describe the frequency of thickness, normal (N) and log−logistic (L−L) distribution should not be used. Elimination of location parameter significantly affects usefulness of probability density functions to modeling empirical distributions of breast height diameter. Gamma and Burr distributions with omitted location parameter gave the best results in description the frequency of breast height diameter. In certain situations, these distributions can also be used to describe the structure of breast height diameter of alder stands.
Źródło:
Sylwan; 2017, 161, 02; 101-113
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 63

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