scholarly journals Mathematical modeling of agglomerates evolution

2019 ◽  
Author(s):  
V.A. Babuk ◽  
N.L. Budnyi ◽  
A.A. Nizyaev
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Solid Propellant ◽  
Combustion Products ◽  
Chemical Transformations ◽  
One Dimensional ◽  
Oxide Particles ◽  
Burning Propellant ◽  
Physical And Chemical

The model of evolution of the condensed products as a part of a flow of combustion products of solid propellant is developed. The model includes the description of physical and chemical transformations for two basic fractions of the condensed products: agglomerates and smoke oxide particles (SOPs). Model testing is carried out using experimental data about evolution of the condensed products for two compositions in the conditions of a one-dimensional flow. These compositions differ considerably in properties of combustion products at a surface of burning propellant. The results of testing give the grounds to draw a conclusion about high enough quality of modeling.

Kinetics and Mechanism of Ecochemical Processes

2020 ◽  
pp. 109-136
Author(s):  
Sergey Olegovich Travin
Keyword(s):  
Mathematical Modeling ◽  
Numerical Experiment ◽  
Food Chain ◽  
Exponential Growth ◽  
Natural Waters ◽  
Stationary States ◽  
The Cost ◽  
Physical And Chemical ◽  
The Impact

Significant efforts of mankind and huge funds were spent to study the mechanisms of environmental processes. Recent decades have been marked by exponential growth of computer power and the accompanying decrease in the cost of computing. With regard to the mathematical modeling of physical and chemical processes that determine the quality of natural waters, atmosphere, and soil, this has led to the development of an extensive approach based on an increase in the number of components and reactions between them taken into consideration. In this chapter, the authors describe features of ecochemical systems and discuss the moments that complicates their prediction. Using the method of numerical experiment, they investigate the behavior of periodic systems with multiple stationary states. One conclusion is that the actual manifestation cannot be used to determine at what stage the impact occurred and to what stage of the food chain it relates. Another conclusion is that systems involving multiple stationary states are prone to bifurcations and chaotic jumps from one limit cycle to another.

scholarly journals Ultrasound-Assisted Cold Pasteurization in Liquid or SC-CO2

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1457
Author(s):  
Anna Abramova ◽  
Vladimir Abramov ◽  
Vadim Bayazitov ◽  
Roman Nikonov ◽  
Igor Fedulov ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
High Efficiency ◽  
Food Product ◽  
Food Products ◽  
Ultrasonic Field ◽  
Chemical Transformations ◽  
Cold Pasteurization ◽  
A New Technique ◽  
Physical And Chemical

Various types of chemical and physical protocols are used, thermal treatment in particular, to increase the quality of bulk food products (for example, dates or some sort of nuts) and extend shelf life, and combinations of methods are frequently used to achieve the best results. However, the use of these processing methods is not always the best option to preserve the initial taste and appearance of food products. For instance, a product may lose its initial natural appearance and acquire different flavors due to chemical transformations that occur at certain temperatures or when the products are treated with chemicals. Non-thermal treatment methods are called “cold” pasteurization. This is a set of advanced techniques that are based on physical and chemical effects that do not result in the structural food-product transformations caused by heating. We have developed and tested a new technique for efficient food-product processing and cold pasteurization in an ultrasonic field under pressure in an atmosphere of supercritical or subcritical carbon dioxide. A laboratory-scale unit that was designed and built for this purpose has experimentally proven the feasibility of this process and demonstrated high efficiency in suppressing pathogenic flora.

scholarly journals Mathematical modeling in the Urumari micro-watershed using Streeter-Phelps mathematical models and the enhanced Do-Bod model

2020 ◽  
Vol 11 (6) ◽  
pp. 332-345
Author(s):  
Lucinewton Silva de Moura ◽  
Ruy Bessa Lopes ◽  
Joseph Simões Ribeiro ◽  
Graciene Do Socorro Taveira Fernandes ◽  
Rodolfo Maduro Almeida ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Water Quality ◽  
Mathematical Models ◽  
Surface Waters ◽  
Nonlinear Function ◽  
Absolute Deviation ◽  
Recovery Mechanism ◽  
Photosynthesis And Respiration

When a certain load of pollutants is dumped in urban surface waters, the natural hydrological parameters are altered and a consequent dispersion of a contaminant occurs. Water self-purification is a natural recovery mechanism that aims to restore the natural parameters of water quality. In the municipality of Santarém, the Urumari micro-watershed, one of the main urban streams and a tributary of the Amazon river, suffers from increasing degradation. Thus, it is necessary to systematically monitor the water quality of the micro-watershed, through mathematical modeling, in order to identify environmental impairment and propose mitigating tools that facilitate self-purification capacity. The aim of this work was to evaluate the degree of disturbance of the Urumari micro-watershed using Streeter-Phelps mathematical models and the Enhanced DO-BOD model. The software Curve Expert 1.4 was used to adjust the coefficients of the mathematical models, using the Levenberg-Marquardt nonlinear function adjustment method. The complete mathematical model of DO and BOD considered the parcels of punctual deficit, microbial BOD, nitrification, sediment demand, photosynthesis and respiration. Three coefficients of the Streeter-Phelps model and six coefficients of the Enhanced DO-BOD model were adjusted according to the experimental data of dissolved oxygen and water travel time. The mathematical models satisfactorily correlated the experimental data. The values of the correlation coefficient, mean absolute deviations and quadratic deviations are for the Streeter-Phelps model and the Enhanced DO-BOD model, respectively. The Streeter-Phelps model presented the best correlation to the experimental data with the values of R2 equal to 0.83; mean absolute deviation equal to 0.56 and quadratic deviations equal to 4.98.

scholarly journals Prediction of Mathematical Models of the Drying Kinetics and Physicochemical Quality of the Chili Pepper

2018 ◽  
Vol 10 (12) ◽  
pp. 377 ◽  
Author(s):  
Semirames do N. Silva ◽  
Joana D’arc P. de Matos ◽  
Polyana B. da Silva ◽  
Zanelli R. T. Costa ◽  
Josivanda P. Gomes ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mathematical Models ◽  
Heat Exposure ◽  
Chili Pepper ◽  
Coefficient Of Determination ◽  
Chemical Transformations ◽  
Experimental Values ◽  
The One ◽  
Time Required

The present work had as objective to determine the kinetics of drying of the chili pepper, to adjust different mathematical models to the experimental values as a function of the water content and to characterize the same in it’s in natura form and after the drying in the temperatures of 60, 70 and 80 °C. The samples were weighted periodically until reaching the equilibrium. The mathematical models of Wang and Singh, Henderson and Pabis, Newton, Page and Thompson were adjusted to the experimental data. The best adjustment was determined in relation to the highest values of the coefficient of determination (R2) and Mean Square Deviation (MSD). The obtained results showed that the drying of the pepper is influenced by the temperature of the drying air. It is concluded that the model of Henderson and Pabis was the one that best fit to the experimental data. The increase of the drying temperature promoted a reduction in the time required for the peppers to reach the moisture of the hygroscopic balance. The parameters of acidity, lipids and proteins remained close at the different drying temperatures used, however higher when compared to the samples in natura. It can be noticed that ashes and vitamin C have suffered considerable decrease as the temperature increased, as a result of the chemical transformations that occurred in the peppers due to heat exposure and loss of moisture.

SOLID PROPELLANT UTILIZATION BY THE BURNING PROPELLANT-COAL AND PROPELLANT-PEAT MIXTURES

1997 ◽  
Vol 4 (1-6) ◽  
pp. 145-152
Author(s):  
A. V. Ananiev ◽  
A. G. Istratov ◽  
V. I. Kolesnikov ◽  
V. N. Marshakov ◽  
A. I. Kurochkin ◽  
...  
Keyword(s):  
Solid Propellant ◽  
Burning Propellant

Орошение томата F1 Донской в открытом грунте Московской области

2019 ◽  
Author(s):  
D.I. Engalychev ◽  
N.A. Engalycheva ◽  
A.M. Menshikh
Keyword(s):  
Experimental Data ◽  
Agricultural Technology ◽  
Tomato Fruits ◽  
River Floodplain ◽  
Yield And Quality ◽  
Open Ground ◽  
Alluvial Meadow ◽  
Standard Production ◽  
Moscow River

Представлены экспериментальные данные о влиянии капельного орошения на урожайность и качество плодов томата при выращивании культуры в открытом грунте Московской области. На плодородных аллювиальных луговых почвах Москворецкой поймы при соблюдении агротехники без орошения в среднем за три года исследований в полевых условиях получена урожайность томата F1 Донской 31,9 т/га, с орошением 48,5 т/га, в т.ч. стандартной продукции 42,6 т/га.The article presents experimental data on the effect of drip irrigation on the yield and quality of tomato fruits when growing crops in open ground of the Moscow Region. On fertile alluvial meadow soils of the Moscow river floodplain, with the observance of agricultural technology without irrigation, the field yield of tomato hybrid F1 Donskoi on average for three years of research was 31.9 t/ha, with irrigation 48.5 t/ha, incl. standard production 42.6 t/ha.

ABOUT NECESSITY OF MATHEMATICAL MODELING OF THE BUSINESS PROCESS OF COST ESTIMATE CALCULATIONS IN THE CONSTRUCTION OF OIL AND GAS FACILITIES

2017 ◽  
pp. 139-145
Author(s):  
R. I. Hamidullin ◽  
L. B. Senkevich
Keyword(s):  
Mathematical Modeling ◽  
Quality Assessment ◽  
Business Process ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Construction Organizations ◽  
The Cost ◽  
Cost Of Construction

A study of the quality of the development of estimate documentation on the cost of construction at all stages of the implementation of large projects in the oil and gas industry is conducted. The main problems that arise in construction organizations are indicated. The analysis of the choice of the perfect methodology of mathematical modeling of the investigated business process for improving the activity of budget calculations, conducting quality assessment of estimates and criteria for automation of design estimates is performed.

Determination of Traces Heavy Metals from Solid Residues Formed by Combustion of Lignite in Relation to Degree of Accessibility in Soil and Plants

2017 ◽  
Vol 68 (10) ◽  
pp. 2363-2366
Author(s):  
Delia Nica Badea
Keyword(s):  
Heavy Metals ◽  
Power Plant ◽  
Thermal Power ◽  
Reference Value ◽  
Combustion Products ◽  
Toxic Heavy Metals ◽  
Area Of Influence ◽  
Risk Potential

The paper evaluates the presence and content of traces of heavy metals Hg, Pb, Ni, Cd (total forms) from coal and solid combustion products, the degree of transfer and accessibility in the area of influence of a lignite power plant. The content of toxic heavy metals in residues are characterized by RE Meiji [ 1 (Pb and Hg) and REMeij �1 (Ni and Cd) for the filter ash. Pb and Ni content in the soil exceeds normal values, and Pb exceeds and alert value for sensitive soils around the residue deposit (70.20 mg.Kg-1). The degree of accessibility of the metals in plants (TF), reported at the Khan reference value (0.5), indicates a significant bioaccumulation level for the metals: Cd (1.9) and Hg (0.6) inside the deposit; Cd (0.39) at the base of the deposit, Hg (0.8) in the area of the thermal power plant. The trace levels of heavy metals analyzed by GFAAS and CVAAS (Hg), indicates a moderate risk potential for food safety and quality of life in the studied area.

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