scholarly journals Development of the Method for Predicting and Calculating the Operation of Sorption Systems for Cleaning the Generator Gas based on Dolomite Use. Part II

2021 ◽  
pp. 31-42
Author(s):  
Mihail Malko ◽  
◽  
Sergey Vasilevich ◽  
Andrei Mitrofanov ◽  
Vadim Mizonov ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Axial Flow ◽  
Thermochemical Conversion ◽  
Local Exchange ◽  
Direct Combustion ◽  
Calculation Step ◽  
Current Characteristics ◽  
The One ◽  
Generator Gas ◽  
Sorption Systems

At present, instead of a direct combustion of solid fuel, its thermochemical conversion is exten-sively used to produce a generator gas. The use of this technology is connected with the need for gas purification. One of the promising and widely spread sorbents for the purification of the generator gas is dolomite, whose particles compose the active component of the bed filters. Forecasting the technological characteristics of the functioning of the bed filters of a various de-sign is an extremely urgent task. The objective of the study is to develop a method for forecast-ing and calculating the operation of sorption systems for purification of the generator gas based on dolomite. It is achieved by constructing and verifying a mathematical model of the function-ing of the bed sorption filter with a radial-axial flow pattern of the generator gas through the do-lomite filling. The Markov chains theory of a mathematical apparatus is used to design the one-dimensional mathematical model of the process with discrete space and time. The main recurrent balance ratio is formed at each calculation step taking into account the current characteristics of the process, which makes the model nonlinear. The significance of the research is that an approach to the problem of increasing the reliability of the description and reliability of forecasting technological processes in a bed filter was proposed based on the construction of mathematical models of these processes, in which the filter is considered as a system with distributed characteristics, and the calculation was based on local exchange potentials between particles and gas.

scholarly journals Spreading of chemical substance after its accidental spillage onto the soil surface under unsaturated conditions and variable porosity

2019 ◽  
pp. 41-44
Author(s):  
Olena Kozhushko ◽  
Petro Martyniuk
Keyword(s):  
Mathematical Model ◽  
Soil Moisture ◽  
Soil Profile ◽  
Moisture Transport ◽  
Soil Surface ◽  
Chemical Substance ◽  
High Concentration ◽  
Solute Transfer ◽  
Variable Porosity ◽  
The One

In this paper we study a mathematical model of soil moisture transport with variable porosity. The problem is set for the case of highly concentrated solute spilled onto soil surface. We investigate the way solute transfer, adsorption of contaminant by soil particles and variable porosity influence infiltration of solute into the soil profile. For that purpose, two models are used: a classical one and the one with consideration of mentioned factors. By comparing the results of both models, we established that high concentration of solute causes moisture transport to transpire more slowly, and the pollutant to remain on the soil surface for longer time. Numerical results indicate that porosity can vary considerably under the conditions of intensive contamination with salts.

Possibility of Evaluating a Depth of Defects as a Hole in a Composite Dielectric Sample by the Parameters of Electric Response to Pulse Mechanical Excitation

2018 ◽  
Vol 781 ◽  
pp. 155-158 ◽  
Author(s):  
Petr Khorsov ◽  
Anatoly Surzhikov ◽  
Vladimir Surzhikov ◽  
Roman Laas
Keyword(s):  
Mathematical Model ◽  
Electromagnetic Response ◽  
Electric Response ◽  
One Dimensional ◽  
Response Parameter ◽  
Dielectric Sample ◽  
Receiver System ◽  
Mechanoelectrical Transformations ◽  
Spurious Component ◽  
The One

The applicability of the method mechanoelectrical transformations (MET) to determine the depth of the macrodefects location in the sample on parameters of the electromagnetic response is evaluated. As the response parameter it was used the phase characteristic of the signal analytical representation.On the one-dimensional mathematical model it was shown the possibility to detect phase response changes when reflected from defect acoustic wave is mixed with the signal spurious component generated by a distributed MET sources. Experimental verification of mathematical model on a sample of concrete was conducted. It has been shown that the sensitivity of the method MET to evaluation of the macrodefect locate depth depends on the wavelength of the excitation pulse and the area of the macrodefect border closest to the emitter-receiver system.

Location of a multinational corporation in a cluster

2016 ◽  
Vol 24 (2) ◽  
pp. 144-167 ◽  
Author(s):  
Dorota Leszczyńska ◽  
Erick Pruchnicki
Keyword(s):  
Mathematical Model ◽  
Knowledge Transfer ◽  
Tacit Knowledge ◽  
Mathematical Expression ◽  
Decision Criterion ◽  
Specific Knowledge ◽  
Content Type ◽  
The One ◽  
Effective Transfer ◽  
The Impact

Purpose A multinational company (MNC) looking to locate within a cluster is mainly interested in gaining access to scarce and highly valuable tacit knowledge. The transfer of such resources first requires sharing a certain degree of architectural and specific knowledge. This paper aims to examine the transfer of systemic technological expertise (specific tacit knowledge) that is incorporated into organisational practices (architectural knowledge). To quantify the level of knowledge transfer involved, the present study defines the architectural distance between the MNC and the cluster. Design/methodology/approach The mathematical expression of acquisition performance is inferred from a conceptual study that formulates hypotheses regarding the impact of these variables on knowledge transfer. The MNC chooses its location in such a way as to maximise this performance. Findings Applying a mathematical model to knowledge transfer between two of the MNC units helps to determine if the locally acquired knowledge could benefit other units of the MNC. Research limitations/implications The present study defines the architectural distance between the MNC and the cluster. This architectural distance is defined by a vector composed of social, organisational, cultural, institutional, technological and geographic distances between the new acquisition and its network of local partners, on the one hand, and the MNC, on the other. Knowledge transfer also depends on the business players’ trust and motivation. Further research through a quantitative study would be useful to improve the links between the proposed mathematical model and the efficiency of an MNC’s location within a cluster. Practical implications The solution to the optimisation problem allows to put forward a simple decision criterion to assist a manager who has to face the problem of an optimal location choice. Originality/value First, this study contributes to a better understanding of how knowledge transfer effects may interact with cluster effects, while explaining a subsidiary’s performance with regard to location. Second, it provides an interpretation of the concept of knowledge embeddedness by showing that the effective transfer of architectural and specific knowledge involves the prior sharing of a certain amount of this knowledge.

Modeling Shrouded Stator Cavity Flows in Axial-Flow Compressors

1999 ◽  
Vol 122 (1) ◽  
pp. 55-61 ◽  
Author(s):  
S. R. Wellborn ◽  
I. Tolchinsky ◽  
T. H. Okiishi
Keyword(s):  
Flow Analysis ◽  
Flow Characteristics ◽  
Axial Flow ◽  
Analysis Tool ◽  
Cavity Flows ◽  
Dimensional Model ◽  
Primary Flow ◽  
One Dimensional ◽  
Stage Matching ◽  
The One

Experiments and computational analyses were completed to understand the nature of shrouded stator cavity flows. From this understanding, a one-dimensional model of the flow through shrouded stator cavities was developed. This model estimates the leakage mass flow, temperature rise, and angular momentum increase through the cavity, given geometry parameters and the flow conditions at the interface between the cavity and primary flow path. This cavity model consists of two components, one that estimates the flow characteristics through the labyrinth seals and the other that predicts the transfer of momentum due to windage. A description of the one-dimensional model is given. The incorporation and use of the one-dimensional model in a multistage compressor primary flow analysis tool is described. The combination of this model and the primary flow solver was used to reliably simulate the significant impact on performance of the increase of hub seal leakage in a twelve-stage axial-flow compressor. Observed higher temperatures of the hub region fluid, different stage matching, and lower overall efficiencies and core flow than expected could be correctly linked to increased hub seal clearance with this new technique. The importance of including these leakage flows in compressor simulations is shown. [S0889-504X(00)00501-8]

scholarly journals A MULTIDIMENSIONAL SUBDIFFUSION MODEL WITH CHEMOTAXIS

2019 ◽  
Vol 11 (2) ◽  
pp. 1
Author(s):  
Bambang Hendriya Guswanto
Keyword(s):  
Mathematical Model ◽  
Probability Measure ◽  
Random Walks ◽  
Unit Ball ◽  
Dimensional Case ◽  
One Dimensional ◽  
The One ◽  
The Mathematical Model

The mathematical model for subdiffusion process with chemotaxis proposed by Langlands and Henry [1] for the one-dimensional case is extended to the multi-dimensional case. The model is derived from random walks process using a probability measure on a n-multidimensional unit ball $S^{n-1}$.

scholarly journals Effect of Rotor Tip Clearance and Configuration on Overall Performance of a 12.77-Centimeter Tip Diameter Axial-Flow Turbine

1979 ◽  
Author(s):  
J. E. Haas ◽  
M. G. Kofskey
Keyword(s):  
Experimental Investigation ◽  
Rotor Blade ◽  
Axial Flow ◽  
Single Stage ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Blade Height ◽  
Overall Performance ◽  
Flow Reaction ◽  
The One

An extensive experimental investigation was made to determine the effect of varying the rotor tip clearance of a 12.77-cm-tip diameter, single-stage, axial-flow reaction turbine. In this investigation, the rotor tip clearance was obtained by use of a recess in the casing above the rotor blades and also by use of a reduced blade height. For the recessed casing configuration, the optimum rotor blade height was found to be the one where the rotor tip diameter was equal to the stator tip diameter. The tip clearance loss associated with this optimum recessed casing configuration was less than that for the reduced blade height configuration.

scholarly journals EVALUATION OF POROUS CONCRETE RESISTANCE TO FREEZING BY DIFFERENT METHODS/AKYTOJO BETONO ATSPARUMO ŠALČIUI, TAIKANT SKIRTINGAS BANDYMŲ METODIKAS, VERTINIMAS

2001 ◽  
Vol 7 (5) ◽  
pp. 397-404
Author(s):  
Romualdas Mačiulaitis ◽  
Dzigita Nagrockienė
Keyword(s):  
Mathematical Model ◽  
Linear Relation ◽  
Frost Resistance ◽  
Specimen Surface ◽  
Freezing And Thawing ◽  
Porous Concrete ◽  
High Service ◽  
Freezing Method ◽  
The Difference ◽  
The One

The article presents results of the comparative investigations into porous concrete specimens resistance to freezing (one-sided and volumetric). It has been determined that there is not any linear relation between the results obtained when calculating both the beginning of specimens disintegration (R=0,2161753) and their disintegration end (R=0,2621269). Besides, the data are very scattered and any other mathematical model did not allow to find a stronger non-linear relation. In addition, the destruction of porous concrete was analysed by measuring the change of relative linear deformations of porous concrete specimens under service resistance to freezing. It has been found that positive linear deformations are characteristic of low service frost resistance porous concrete specimens both during the one-sided freezing and thawing. When these deformations after some cycles reach (1,2–1,7%), the specimen surface disintegrates. Negative linear deformations are characteristic of specimens of high service frost resistance during one-sided freezing and thawing. The specimens of average service frost resistance (successfully resisted 25–30 cycles) can be characterised by the development of positive relative deformations during freezing and thawing. The processes have been investigated in detail taking place in identical specimens when they are investigated under different heat draining methods (one-sided and volumetric). The difference of humidity migration and localisation in respect of the freezing method has been disclosed. Some conclusions have been deduced from the investigation.

scholarly journals Prediction of Al2O3 leaching recovery in the Bayer process using statistical multilinear regresion analysis

2010 ◽  
Vol 46 (2) ◽  
pp. 161-169 ◽  
Author(s):  
I. Djuric ◽  
P. Djordjevic ◽  
I. Mihajlovic ◽  
Dj. Nikolic ◽  
Z. Zivkovic
Keyword(s):  
Mathematical Model ◽  
Bayer Process ◽  
Alumina Production ◽  
Statistical Reliability ◽  
Leaching Process ◽  
Input Parameters ◽  
Statistical Sample ◽  
One Year ◽  
The One ◽  
The Mathematical Model

This paper presents the results of defining the mathematical model which describes the dependence of leaching degree of Al2O3 in bauxite from the most influential input parameters in industrial conditions of conducting the leaching process in the Bayer technology of alumina production. Mathematical model is defined using the stepwise MLRA method, with R2 = 0.764 and significant statistical reliability - VIF<2 and p<0.05, on the one-year statistical sample. Validation of the acquired model was performed using the data from the following year, collected from the process conducted under industrial conditions, rendering the same statistical reliability, with R2 = 0.759.

scholarly journals Aluminum bar cutting optimization for door and window manufacturing

DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 155-162
Author(s):  
Ageu Araujo Machado ◽  
João Carlos Zayatz ◽  
Marcos Meurer Da Silva ◽  
Guilherme Melluzzi Neto ◽  
Gislaine Camila Lapasini Leal ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Real Data ◽  
Raw Material ◽  
Process Efficiency ◽  
Computational Time ◽  
Advantages And Disadvantages ◽  
Key Factor ◽  
Material Procurement ◽  
The One ◽  
The Mathematical Model

This study aims to optimize the one-dimensional cutting process of aluminum bars for the production of aluminum doors. Reducing the use of bars and the amount of material that becomes scrap is a key factor in process efficiency, reducing the need for raw material procurement. The mathematical model used considers the size of the bar, the number and size of cuts, the size of the leftovers that can be used and the size of the leftovers that are considered scrap. Based on real data from a company in the aluminum frame segment, the mathematical model was used to simulate three different scenarios. Three different objective functions were used in the simulations, and the results obtained in each scenario were described in order to indicate the advantages and disadvantages of using each objective function. For the instance sizes studied, the model is able to obtain optimal solutions with little computational time.

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