scholarly journals Mathematical Model of the Deaeration of Finely Dispersed Solid Media in a Spherical Matrix of a Roller-Type Apparatus

2021 ◽  
Vol 9 ◽  
Author(s):  
Anna Kapranova ◽  
Mikhail Tarshis ◽  
Natalya Badaeva ◽  
Irina Sheronina
Keyword(s):  
Solid Particle ◽  
Plane Deformation ◽  
Heterogeneous Systems ◽  
Conveyor Belt ◽  
Initial Time ◽  
Time Interval ◽  
Deformation Model ◽  
Spherical Granule ◽  
Interphase Interaction ◽  
Dispersed Material

The additional operation of deaeration (compaction) of powders affects the quality of many products of chemical industries, the conditions for their delivery. Otherwise, energy consumption increases significantly. The aim of this work is the modeling of the deaeration of solid finely dispersed media in a gap with perforated hemispherical shapes on the surfaces of the shaft and conveyor belt within the framework of the mechanics of heterogeneous systems. A plane-deformation model is described, neglecting the forces of interphase interaction and taking into account the compressibility of a solid-particle-gas mixture without elastoplastic deformations. The model assumes consideration of the movement of (1) the components of the solid skeleton together with the carrying phase as a whole; (2) gas in an isothermal state through the pores of a finely dispersed material. This work is devoted to the study of part (a), i.e., behavior of the solid particle-gas system as a whole. The efficiency of the seal-deaerator is estimated using the obtained analytical dependencies for the main strength and speed indicators. The change in the degree of compaction of a spherical granule made of kaolin with given strength characteristics is investigated. It is shown that for the initial time interval up to 3.7⨯10−2 s, the growth of the porosity value relative to the horizontal coordinate along the conveyor belt is exponential and increases by a factor of 1.1. After eight such time intervals, the porosity values stabilize along the indicated coordinate with an increase of more than 1.4 times from the initial value.

scholarly journals Hydrodynamic Model of Transport System

2020 ◽  
Keyword(s):  
Hydrodynamic Model ◽  
Transition Period ◽  
Initial Conditions ◽  
Flow Line ◽  
Conveyor Belt ◽  
Deformation Model ◽  
Longitudinal Vibrations ◽  
Production Flow ◽  
Dynamic Stresses ◽  
Transportation Route

A hydrodynamic model of production systems with a flow method of organizing production is considered. The basic macro-parameters of the state of the production flow line and the relationship between them are determined. The choice of a lot of moment approximation for modelling the production line is justified. It is shown that the conveyor-type flow line is a complex dynamic system with distributed parameters. The boundary value problem is formulated for the longitudinal vibrations of the conveyor belt when the material moves along the transportation route. It is assumed that there is no sliding of material along the conveyor belt, and the deformation that occurs in the conveyor belt is proportional to the applied force (Hooke's elastic deformation model). The significant effect of the uneven distribution of the material along the transportation route on the propagation velocity of dynamic stresses in the conveyor belt is shown. When constructing the boundary and initial conditions, the recommendations of DIN 22101: 2002-08 were used. The mechanism of the occurrence of longitudinal vibrations of the conveyor belt when the material moves along the transportation route is investigated. The main parameters of the model that cause dynamic stresses are determined. It is shown that dynamic stresses are formed as a result of a superposition of stresses in the direct and reflected waves. Analytical expressions are written that make it possible to calculate the magnitude of dynamic stresses in a conveyor belt and determine the conditions for the occurrence of destruction of the conveyor belt. The characteristic phases of the initial movement of the material along the technological route are considered. The process of the emergence of dynamic stresses with the constant and variable acceleration of the conveyor belt is investigated. The dynamics of stress distribution along the transportation route is presented. It is shown that the value of dynamic stresses can exceed the maximum permissible value, which leads to the destruction of the conveyor belt or structural elements. The transition period is estimated, which is required to ensure a trouble-free mode of transport operation during acceleration or braking of the conveyor belt. The use of dimensionless parameters allows us to formulate criteria for the similarity of conveyor systems.

scholarly journals Initial Condition Sensitivity and Predictability of a Severe Extratropical Cyclone Using a Moist Adjoint

2014 ◽  
Vol 142 (1) ◽  
pp. 320-342 ◽  
Author(s):  
James D. Doyle ◽  
Clark Amerault ◽  
Carolyn A. Reynolds ◽  
P. Alex Reinecke
Keyword(s):  
Nonlinear Models ◽  
Conveyor Belt ◽  
Extratropical Cyclone ◽  
Temperature Fields ◽  
Initial Time ◽  
Mean Flow ◽  
Wind Fields ◽  
Moisture Sensitivity ◽  
Low Level ◽  
The Mean

Abstract The sensitivity and predictability of a rapidly developing extratropical cyclone, Xynthia, that had a severe impact on Europe is explored using a high-resolution moist adjoint modeling system. The adjoint diagnostics indicate that the intensity of severe winds associated with the front just prior to landfall was particularly sensitive to perturbations in the moisture and temperature fields and to a lesser degree the wind fields. The sensitivity maxima are found in the low- and midlevels, oriented in a sloped region along the warm front, and maximized within the warm conveyor belt. The moisture sensitivity indicates that only a relatively small filament of moisture within an atmospheric river present at the initial time was critically important for the development of Xynthia. Adjoint-based optimal perturbations introduced into the tangent linear and nonlinear models exhibit rapid growth over 36 h, while initial perturbations of the opposite sign show substantial weakening of the low-level jet and a marked reduction in the spatial extent of the strong low-level winds. The sensitivity fields exhibit an upshear tilt along the sloping warm conveyor belt and front, and the perturbations extract energy from the mean flow as they are untilted by the shear, consistent with the PV unshielding mechanism. The results of this study underscore the need for accurate moisture observations and data assimilation systems that can adequately assimilate these observations in order to reduce the forecast uncertainties for these severe extratropical cyclones. However, given the nature of the sensitivities and the potential for rapid perturbation and error growth, the intrinsic predictability of severe cyclones such as Xynthia is likely limited.

Lattice Green’s Functions in Nonlinear Analysis of Defects

2006 ◽  
Vol 74 (4) ◽  
pp. 686-690 ◽  
Author(s):  
S. Haq ◽  
A. B. Movchan ◽  
G. J. Rodin
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Green's Functions ◽  
Model Problem ◽  
Green’S Functions ◽  
Plane Deformation ◽  
Deformation Model ◽  
Linear Region ◽  
Nonlinear Zone ◽  
Element Method

A method for analyzing problems involving defects in lattices is presented. Special attention is paid to problems in which the lattice containing the defect is infinite, and the response in a finite zone adjacent to the defect is nonlinear. It is shown that lattice Green’s functions allow one to reduce such problems to algebraic problems whose size is comparable to that of the nonlinear zone. The proposed method is similar to a hybrid finite-boundary element method in which the interior nonlinear region is treated with a finite element method and the exterior linear region is treated with a boundary element method. Method details are explained using an anti-plane deformation model problem involving a cylindrical vacancy.

scholarly journals PREDIKSI PELUANG KEMATIAN DAN KELAHIRAN MURNI PENDUDUK KABUPATEN MERAUKE MENGGUNAKAN METODE BIRTH AND DEATH PROCESS

2021 ◽  
Vol 15 (1) ◽  
pp. 095-102
Author(s):  
Minuk Riyana ◽  
Marius Agustinus Welliken K.
Keyword(s):  
Population Data ◽  
The Elderly ◽  
Death Process ◽  
Initial Time ◽  
Time Interval ◽  
Birth And Death Process ◽  
Female Sex ◽  
A Value ◽  
Calculation Results ◽  
Process Method

This study aims to estimate the probability of birth and death purely based on gender and population data of Merauke City. The chance of birth and death will be used to estimate the life table of the elderly in a population of the City of Merauke. The method used in this research is the birth and process method. The Birth and death process method which is a Poisson distribution is used to predict the chances of birth and death at time t. If the birth and death process fulfills the linearity requirements, then the processes are called the Yule-Furry process. This research discusses the stochastic process of pure birth-death with two sexes in the Yule-Furry Process. From the data on the population of Merauke district which is divided based on the sex of men and women using the pure birth and death model, the calculation results show that the probability value at the time interval 0 ≤ t <1 hour, at the initial time t = 0, the chance of individual birth at female sex is stationary at a value of 0.1762, while the chance of individual death for female sex is stationary at a value of 0.00154. The odds of birth and death in male individuals are stationary at a value of 0.305034 and 0, 059487.

scholarly journals Microbial assessment of beef in selected areas of Mymensingh district in Bangladesh

2018 ◽  
Vol 46 (4) ◽  
pp. 244-248 ◽  
Author(s):  
S Afrin ◽  
MM Hossain ◽  
M Khan ◽  
MD Hossain
Keyword(s):  
Microbial Contamination ◽  
Total Coliform ◽  
Viable Count ◽  
Initial Time ◽  
Time Interval ◽  
Microbial Count ◽  
Standard Protocol ◽  
Microbial Counts ◽  
Beef Meat ◽  
Total Yeast

This study was conducted to evaluate microbial load of beef meat during handling and selling in market. Total 12 samples were collected from K.R market, Sheshmore market, Kewatkhali bazaar and Mymensingh Sadar market. These samples were subjected to determine Total Viable Count (TVC), Total Coliform Count (TCC) and Total Yeast and Mould Count (TYMC) by using standard protocol at 0 hr, 2hrs and 5hrs time intarvel. The microbial counts of beef at different markets were high but there were no significant differences (p>0.05) among the markets. In every cases with the increased of time interval all types of microbial count increased significantly (p<o.o1) than the initial time. Microbial contamination of beef occurs as plant workers and machinery repeatedly touch contaminated surfaces and the carcass. Thoughtful design of operating procedures, especially for flaying and evisceration, can greatly reduce this problem. Frequent washing and sanitizing of hands, tools, and machinery is required in order to remove bacteria before they reach the exposed surface of the carcass.Bang. J. Anim. Sci. 2017. 46 (4): 244-248

A two-point Markov chain boundary-value problem

1993 ◽  
Vol 25 (3) ◽  
pp. 607-630 ◽  
Author(s):  
D. J. Daley ◽  
L. D. Servi
Keyword(s):  
Markov Chain ◽  
Boundary Value Problem ◽  
Boundary Value ◽  
Sample Path ◽  
Maximum Likelihood Estimates ◽  
Initial Time ◽  
Time Interval ◽  
Birth Process ◽  
Waiting Room ◽  
Time Point

The two-point Markov chain boundary-value problem discussed in this paper is a finite-time version of the quasi-stationary behaviour of Markov chains. Specifically, for a Markov chain {Xt:t = 0, 1, ·· ·}, given the time interval (0, n), the interest is in describing the chain at some intermediate time point r conditional on knowing both the behaviour of the chain at the initial time point 0 and that over the interval (0, n) it has avoided some subset B of the state space. The paper considers both ‘real time' estimates for r = n (i.e. the chain has avoided B since 0), and a posteriori estimates for r < n with at least partial knowledge of the behaviour of Xn. Algorithms to evaluate the distribution of Xr can be as small as O(n3) (and, for practical purposes, even O(n2 log n)). The estimates may be stochastically ordered, and the process (and hence, the estimates) may be spatially homogeneous in a certain sense. Maximum likelihood estimates of the sample path are furnished, but by example we note that these ML paths may differ markedly from the path consisting of the expected or average states. The scope for two-point boundary-value problems to have solutions in a Markovian setting is noted.Several examples are given, together with a discussion and examples of the analogous problem in continuous time. These examples include the basic M/G/k queue and variants that include a finite waiting room, reneging, balking, and Bernoulli feedback, a pure birth process and the Yule process. The queueing examples include Larson's (1990) ‘queue inference engine'.

scholarly journals Monotone-Iterative Method for the Initial Value Problem with Initial Time Difference for Differential Equations with “Maxima”

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
S. Hristova ◽  
A. Golev
Keyword(s):  
Differential Equations ◽  
Initial Value Problem ◽  
Upper And Lower Solutions ◽  
Successive Approximations ◽  
Initial Time ◽  
Time Interval ◽  
Monotone Iterative Method ◽  
Initial Value ◽  
Monotone Iterative ◽  
The Given

The object of investigation of the paper is a special type of functional differential equations containing the maximum value of the unknown function over a past time interval. An improved algorithm of the monotone-iterative technique is suggested to nonlinear differential equations with “maxima.” The case when upper and lower solutions of the given problem are known at different initial time is studied. Additionally, all initial value problems for successive approximations have both initial time and initial functions different. It allows us to construct sequences of successive approximations as well as sequences of initial functions, which are convergent to the solution and to the initial function of the given initial value problem, respectively. The suggested algorithm is realized as a computer program, and it is applied to several examples, illustrating the advantages of the suggested scheme.

scholarly journals Ornithonyssus sylviarum (Acari: Macronyssidae) parasitism among poultry farm workers in Minas Gerais state, Brazil

2020 ◽  
Vol 50 (7) ◽  
Author(s):  
Cristina Mara Teixeira ◽  
Tiago Mendonça de Oliveira ◽  
Amanda Soriano-Araújo ◽  
Leandro do Carmo Rezende ◽  
Paulo Roberto de Oliveira ◽  
...  
Keyword(s):  
Laying Hens ◽  
Control Strategies ◽  
Skin Lesions ◽  
Conveyor Belt ◽  
Minas Gerais ◽  
Egg Laying ◽  
Farm Workers ◽  
Time Interval ◽  
Ornithonyssus Sylviarum ◽  
Epidemiological Characteristics

ABSTRACT: Ornithonyssus sylviarum is a hematophagous mite present in wild, domestic, and synanthropic birds. However, this mite can affect several vertebrate hosts, including humans, leading to dermatitis, pruritus, allergic reactions, and papular skin lesions. This study evaluated the epidemiological characteristics of O. sylviarum attacks on poultry workers, including data on laying hens, infrastructure and management of hen houses, and reports of attacks by hematophagous mites. In addition, a case of mite attack on a farm worker on a laying farm in the Midwest region in Minas Gerais is presented. It was found that 60.7% farm workers reported attacks by hematophagous mites. Correspondence analysis showed an association between reports of mite attacks in humans with (1) presence of O. sylviarum in the hen house, (2) manual removal of manure by employees, and (3) history of acaricide use. The specimens collected from the location were confirmatively identified as O. sylviarum. O. sylviarum attacks ave not been reported when manure was removed in a shorter time interval and did not use acaricide in the sheds when the removal was done by manure conveyor belt. Parasitism by O. sylviarum should be considered a relevant occupational hazard affecting employees working in direct contact with commercial egg-laying hens in Minas Gerais. We emphasized the need to monitor hen infestations by this mite to improve the development of mite control strategies.

scholarly journals A New Class of “Growth Functions” with Polynomial Variable Transfer Generated by Real Reaction Networks

2020 ◽  
Vol 20 (6) ◽  
pp. 74-81
Author(s):  
Nikolay Kyurkchiev
Keyword(s):  
Growth Models ◽  
Reaction Network ◽  
Initial Time ◽  
Reaction Networks ◽  
Time Interval ◽  
Adequate Model ◽  
Specific Data ◽  
Numerical Examples ◽  
New Class ◽  
Growth Functions

AbstractIn [4, 5], two classes of growth models with “exponentially variable transfer” and “correcting amendments of Bateman-Gompertz-Makeham-type” based on a specific extended reaction network have been studied [1]. In this article we will look at the new scheme with “polynomial variable transfer”. The consideration of such a dynamic model in the present article is dictated by our passionate desire to offer an adequate model with which to well approximate specific data in the field of computer viruses propagation, characterized by rapid growth in the initial time interval. Some numerical examples, using CAS Mathematica illustrating our results are given.

Parameter Identification of Lorenz System with Incomplete Information: Case of One Known and Two Unknown Functions

2021 ◽  
Vol 55 ◽  
pp. 103-121
Author(s):  
Michael Y. Shatalov ◽  
Samuel A. Surulere ◽  
Lilies M. Phadime ◽  
Thomson T. Mthombeni
Keyword(s):  
Parameter Identification ◽  
Lorenz System ◽  
Initial Time ◽  
Accurate Estimation ◽  
Lorenz Attractor ◽  
Time Interval ◽  
Problem Solution ◽  
Unknown Parameters ◽  
Random Components ◽  
Discrete Values

In the present paper, which is the continuation of the previous one, the problem of parameter identification of the Lorenz system is solved in assumption that only one of three functions is known at discrete time instants on finite time initial time interval. Two other functions are assumed to be unknown. The regular methods of guess values determination of the unknown parameters are developed. They are based on the Lagrange multiplier and auxiliary parameters approaches. A novel method of initial value problem solution is proposed in which the abovementioned guess values are used for more accurate estimation of the system parameters. It is demonstrated that the proposed IVP method simultaneously solves three different tasks: the problem of function interpolation from its discrete values on the initial time interval; the problem of unknown functions reconstruction on the same time interval, and the problem of extrapolation of all functions on limited time interval. It is also shown that the proposed method reconstructs the Lorenz attractor from limited data volume and data including random components.

Sign in / Sign up

Export Citation Format

Share Document