scholarly journals Optimization of the process of mixing liquid-phase heterogeneous products by mathematical modeling

2020 ◽  
Vol 82 (1) ◽  
pp. 47-52
Author(s):  
A. B. Emelyanov ◽  
M. V. Kopylov ◽  
D. A. Kazartsev ◽  
M. K. Abrahamyan ◽  
M. V. Nechaev
Keyword(s):  
Software Package ◽  
Desirability Function ◽  
Mixing Time ◽  
Experimental Studies ◽  
Experimental Setup ◽  
Mixing Process ◽  
Optimal Conditions ◽  
Microsoft Excel ◽  
The Matrix ◽  
Mixer Shaft

The main objective of the experimental study of all processes is the analysis, study and generalization of all available results. In accordance with the idea of a step search, the experiment was carried out in several stages. The number of stages and actions at each of them depended on the results of the previous stage and the ultimate goal of research. The ultimate goal of the study is to determine the optimal conditions for the process of mixing the liquid aggregates to obtain a homogeneous structure. Studies of the mixing process were carried out on an experimental setup created at the department. To process experimental studies, the STATISTICA 12 software package was used. To obtain the regression equation, the matrix data were processed using the Microsoft Excel 2010 software package. To optimize the process, the output parameters were converted to a dimensionless scale of desirability d. It was established that the desirability function D, which characterizes the adequacy of the obtained values, has an extremum in experiment 12 and is 0.733666. Based on the obtained data, the following parameters should be considered optimal when mixing liquid aggregates: the peripheral speed of the mixer shaft is within 4 m/s, while the mixing time is 8 s and the refrigerant concentration is 20%.

scholarly journals Influence of the addition sequence of PVA-fibers and water on mixing and rheological behavior of mortars

2016 ◽  
Vol 9 (2) ◽  
pp. 226-243 ◽  
Author(s):  
M. S. de França ◽  
F. A. Cardoso ◽  
R. G. Pileggi
Keyword(s):  
Rheological Behavior ◽  
Mechanical Performance ◽  
Mixing Time ◽  
Mix Design ◽  
Mixing Process ◽  
Water Addition ◽  
Test Parameters ◽  
The Matrix ◽  
Mixing Sequences ◽  
The Moment

ABSTRACT The mixing process of fiber-containing cementitious suspensions is a crucial factor to obtaining a good dispersion of fibers and guarantee adequate mechanical performance of the hardened products. The addition of fibers into the suspension causes reduction of the fluidity of the system due to factors inherent to the fibers, the matrix and their interaction. During mixing, these interactions make dispersion and homogenization processes more difficult due to the formation of fibers - particles agglomerates. Conventional techniques to assess workability of mortars are inadequate to evaluate the rheological behavior of fiber-reinforced systems, in which parameters like viscosity and yield stress are not completely taken into account. Therefore, this work employs rotational rheometry to evaluate the influence of fiber and water addition sequences on mixing and rheological behavior of mortars containing Polyvinyl Alcohol (PVA) fibers. Constant test parameters were: mixing time of 317s; impeller velocity 126.5 rpm; water flow 128g/s. A constant mix design was used with a water content of 16%wt, and a 0.2%vol of fibers were added to the reference composition. Four mixing sequences were studied: S1 and S2 are based on the addition of fibers at different stages of the mixing process; while in S3 and S4 not only the fibers are added at different stages, but also the water addition is performed in two steps (25% first and 75% latter).Results showed that it is possible to optimize the mixing step of fiber-containing systems by changing the moment of fiber addition into the mixture. The introduction of fibers after mixing the dry mortar with water, when it already had achieved its fluidity point, demanded a lower mixing effort and produced a more flowable material.

scholarly journals Effect of design and kinematic parameters on energy requirement in inclined screw mixer

2019 ◽  
Vol 18 (4) ◽  
pp. 408-413
Author(s):  
V. F. Khlystunov ◽  
S. V. Braginets ◽  
A. S. Alferov ◽  
M. V. Chernutskiy
Keyword(s):  
Mixing Time ◽  
Experimental Studies ◽  
Filling Ratio ◽  
Design Parameters ◽  
Shaft Speed ◽  
Optimization Criteria ◽  
Screw Mixer ◽  
Mixing Chamber ◽  
Mixer Shaft ◽  
Chamber Angle

Introduction. Rational parameters and modes of an inclined batch screw mixer are validated to achieve the lowest energyintensive feed mixing under observance of the zootechnical requirements for the feed quality on uneven mixing. The establishment of functional dependences between parameters and modes enables to design power-efficient equipment for the on-farm feed production.Materials and Methods.Experimental studies of the feed mixing were implemented on an inclined screw batch feed mixer. The experimental design included variation of four independent factors: mixer shaft speed, filling ratio of the mixing chamber, mixing time, and mixing chamber angle. Mixing irregularity and energy intensity of the process were taken as optimization criteria characterizing the mixing efficiency.Research Results.The optimization criteria versus the variability level factor, which are two-dimensional sections of the second-order response surfaces, are plotted. The rational values at mixing irregularity of less than 5% were as follows: mixer shaft speed was 27.5-36.5 min-1 , filling ratio of the mixing chamber was 0.43–0.51, mixing time was 3.0–4.2 min, mixing chamber angle was 22°–25°. At such parameter values, the mixing irregularity will be minimal, and it will be 4.10– 4.18%, and the process intensity is from 2.08 to 2.16 kW • h/t.Discussion and Conclusions.The dependences obtained as a result of the experimental studies allowed establishing the domain of rational design parameters and modes of an inclined batch screw mixer. The results obtained can be used in further studies under the development of initial requirements for the creation of new technical means with a gravitation effect of intensive mixing.

Computational studies of the mitochondrial carrier family SLC25. Present status and future perspectives

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Andrea Pasquadibisceglie ◽  
Fabio Polticelli
Keyword(s):  
Transport Mechanism ◽  
Experimental Studies ◽  
Intermembrane Space ◽  
Mitochondrial Carrier ◽  
Mitochondrial Homeostasis ◽  
The Matrix ◽  
Mitochondrial Carrier Family ◽  
Mitochondrial Intermembrane Space ◽  
Computational Analyses

Abstract The members of the mitochondrial carrier family, also known as solute carrier family 25 (SLC25), are transmembrane proteins involved in the translocation of a plethora of small molecules between the mitochondrial intermembrane space and the matrix. These transporters are characterized by three homologous domains structure and a transport mechanism that involves the transition between different conformations. Mutations in regions critical for these transporters’ function often cause several diseases, given the crucial role of these proteins in the mitochondrial homeostasis. Experimental studies can be problematic in the case of membrane proteins, in particular concerning the characterization of the structure–function relationships. For this reason, computational methods are often applied in order to develop new hypotheses or to support/explain experimental evidence. Here the computational analyses carried out on the SLC25 members are reviewed, describing the main techniques used and the outcome in terms of improved knowledge of the transport mechanism. Potential future applications on this protein family of more recent and advanced in silico methods are also suggested.

The Engineering Characteristics of Snow Skis—Part 1: Static Bending and Torsional Characteristics

1975 ◽  
Vol 97 (1) ◽  
pp. 131-137 ◽  
Author(s):  
A. Deak ◽  
J. Jorgensen ◽  
J. Vagners
Keyword(s):  
Experimental Studies ◽  
Beam Theory ◽  
Experimental Techniques ◽  
Experimental Setup ◽  
New Materials ◽  
Engineering Characteristics ◽  
Analytical Results ◽  
Geometric Arrangements

This paper presents the results of analytical and experimental studies of static bending and torsional characteristics of snow skis. The purpose of the work is to develop analytical and experimental techniques that would be useful to the ski designer who must continually explore the applicability of new materials and geometric arrangements to snow ski construction. A brief review of composite shallow beam theory is presented in a form directly applicable to ski analysis. The experimental setup to verify the analytical results is described.

scholarly journals Theoretical and experimental studies of a gas stamping device with a piston pressure multiplier

2019 ◽  
Vol 18 (1) ◽  
pp. 163-173
Author(s):  
A. Yu. Botashev ◽  
R. A. Bayramukov
Keyword(s):  
Theoretical Analysis ◽  
Experimental Studies ◽  
Fuel Mixture ◽  
Small Scale ◽  
Scale Production ◽  
Pressure Treatment ◽  
Energy Of Combustion ◽  
Stamping Process ◽  
Pressure Multiplier ◽  
The Matrix

In many industries, the share of small-scale production plants is significant. In these conditions, compared with traditional methods of pressure treatment, pulse pressure treatment methods, one of the varieties of which is gas stamping, are more efficient. However, the known devices of gas stamping provide mainly stamping of thin-walled parts. To expand the technological capabilities of gas stamping, the authors developed a gas stamping device with a piston pressure multiplier, in which heating and deformation of the stamping workpiece is carried out using the energy of combustion of fuel mixtures in the combustion chamber, in the working cylinder and in the cavity of the matrix. This article is devoted to the study of the workflow of this device. Theoretical analysis of the workflow was carried out, and, as a result, a pattern was determined for the variation of the pressure that performs the stamping process in the working cylinder. In particular, it was found that at the final stage of the stamping process, due to the energy of combustion of the fuel mixture, the pressure in the working cylinder increases 1.5...2 times, which allows a significant increase in the thickness of the parts to be stamped. An experimental gas stamping device with a piston pressure multiplier was developed, and experimental studies were carried out. The studies confirmed the main results of the theoretical analysis: the discrepancy between the theoretical and experimental values of the degree of pressure multiplication in the working cylinder does not exceed 11%.

scholarly journals OXIDATIVE DIMERIZATION OF METHANE TO C2 HYDROCARBONS

2021 ◽  
Vol 447 (3) ◽  
pp. 18-24
Author(s):  
D.B. Augaliev ◽  
M.K. Erkibaeva ◽  
A.O. Aidarova ◽  
S.А. Tungatarova ◽  
T.S. Baizhumanova
Keyword(s):  
Natural Gas ◽  
Raw Materials ◽  
Continuous Production ◽  
Experimental Studies ◽  
Optimal Conditions ◽  
Alternative Source ◽  
Oil Reserves ◽  
Oxidative Conversion Of Methane ◽  
C2 Hydrocarbons ◽  
Shs Method

The world's oil reserves are decreasing every day due to the continuous production and processing of the most modern technologies. Scientists all over the world are looking for various raw materials and methods to use the vast resources of natural gas as a substitute for petrochemicals. In this regard, great attention is drawn to natural gas as an alternative source of raw materials for petrochemical industries. The purpose of this work is to study the reaction of methane dehydrogenation on new 20%La-10%Ce20%Mg-50% glycine catalysts prepared by the SHS method to identify the optimal conditions for their preparation, concentration and ratio of metals, the influence of contact time and process temperature on the direction and mechanism of the reaction. The results of the study of 20% La-10% Ce-20% Mg-50% glycine catalyst prepared by the SHS method in the process of oxidative dehydrogenation of methane into C2 hydrocarbons are presented. On the basis of experimental studies, it was found that the composition of the catalyst exhibits high activity in the above reaction under the found optimal conditions. Thus, the influence of reaction temperature on the developed composition of catalysts for oxidative conversion of methane has been determined that the optimum temperature for the selective formation of ethane and ethylene is T=700o С. It was found that for selective oxidation of a mixture of CH4: O2 : Ar in C2 hydrocarbons the optimal conditions are: T=700o С, CH4:O2=2,5:1, 5000 h-1.

Micromechanical Analysis of Nonlinear Response of Unidirectional Composites: A Fundamental Approach

2001 ◽  
Author(s):  
Virendra R. Jadhav ◽  
Srinivasan Sridharan
Keyword(s):  
Mechanical Model ◽  
Nonlinear Response ◽  
Experimental Studies ◽  
Matrix Cracking ◽  
Type Model ◽  
Unidirectional Composites ◽  
The Matrix ◽  
Experimental Response ◽  
Square Cells ◽  
Experimental Comparisons

Abstract Micromechanical models with different representative volume elements have been developed to study their ability to predict nonlinear response of unidirectional composites. A simple, square cells type micro-mechanical model similar to those widely used by other researchers is compared with a more advanced 3-phase finite element based micro-mechanical model. The models utilize the “bulk” properties of the matrix without attempting to “tune” the model to fit with experimental response of laminae. This is a more fundamental approach and constitutes a departure from current practice. The models account for shear softening, matrix cracking and the presence of residual stresses. A smeared cracking approach was used to characterize the micro-cracking in matrix. Experimental studies were performed on laminae, laminates and cylinders made from carbon epoxy composites. Experimental comparisons show that the more accurate micro-mechanical model with proper partial cracking options provides good bounds on experimental response with consistent accuracy. A square cells type model however is not consistent in its predictions, thus raising questions about its applicability in any general micro-mechanics based analysis.

JUSTIFICATION OF HYDROCYCLONE DESIGN FOR WASTE WATER PURIFICATION

2021 ◽  
Author(s):  
Владимир Александрович Савчук ◽  
Сергей Ильдусович Валеев
Keyword(s):  
Waste Water ◽  
Water Purification ◽  
Experimental Studies ◽  
Optimal Conditions ◽  
Pressure Fields ◽  
Light Impurities

Проведены экспериментальные исследования полей скоростей и давлений в цилиндрическом гидроциклоне для разделения эмульсий с малым содержанием легких примесей (не более 1%). Полученные данные позволяют сделать вывод, что в цилиндрическом гидроциклоне по сравнению с цилиндроконическим гидроциклоном обеспечиваются оптимальные условия для сепарации жидких частиц. Experimental studies of velocity and pressure fields in a cylindrical hydrocyclone for the separation of emulsions with a low content of light impurities (no more than 1%) have been carried out. The data obtained allow us to conclude that in a cylindrical hydrocyclone, in comparison with a cylindrical-conical hydrocyclone, optimal conditions are provided for the separation of liquid particles.

scholarly journals Experimental investigation of a gel fuel combustion process initiated by a hot particle

2018 ◽  
Vol 209 ◽  
pp. 00025
Author(s):  
Aleksandr Nigay ◽  
Dmitriy Glushkov
Keyword(s):  
High Speed ◽  
Initial Temperature ◽  
Combustion Process ◽  
Experimental Studies ◽  
Chemical Processes ◽  
Metal Particles ◽  
Experimental Setup ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Physical And Chemical

Experimental studies were performed for crude oil-based fuel samples. The initial temperature of the samples varied down to 120 K. Ignition was performed by single metal particles of various shapes and temperatures, which reached 1350 K. A specially developed experimental setup allowed recording of the proceeding processes at a high speed. As a result, the characteristics of physical and chemical processes were analysed. Conditions necessary for stable ignition and ignition delay times were determined depending on various conditions.

scholarly journals Hydrodynamics and Mass Transfer Analysis in BioFlow® Bioreactor Systems

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1311 ◽  
Author(s):  
Marian Kordas ◽  
Maciej Konopacki ◽  
Bartłomiej Grygorcewicz ◽  
Adrian Augustyniak ◽  
Daniel Musik ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Mixing Time ◽  
Mass Transfer Rate ◽  
Mass Transfer Process ◽  
Mixing Process ◽  
Stirred Tanks ◽  
Mixing Energy ◽  
Biotechnological Processes ◽  
Liquid Transfer ◽  
Mathematical Relationships

Biotechnological processes involving the presence of microorganisms are realized by using various types of stirred tanks or laboratory-scale dual-impeller commercial bioreactor. Hydrodynamics and mass transfer rate are crucial parameters describing the functionality and efficiency of bioreactors. Both parameters strictly depend on mixing applied during bioprocesses conducted in bioreactors. Establishing optimum hydrodynamics conditions for the realized process with microorganisms maximizes the yield of desired products. Therefore, our main objective was to analyze and define the main operational hydrodynamic parameters (including flow field, power consumption, mixing time, and mixing energy) and mass transfer process (in this case, gas–liquid transfer) of two different commercial bioreactors (BioFlo® 115 and BioFlo® 415). The obtained results are allowed using mathematical relationships to describe the analyzed processes that can be used to predict the mixing process and mass transfer ratio in BioFlo® bioreactors. The proposed correlations may be applied for the design of a scaled-up or scaled-down bioreactors.

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