Research of hydrodynamics of gas flow filtration through a stationary layer of crushed cotton stalks (wild cotton)

The object of this research is the hydrodynamics of the stationary layer of crushed cotton stalks. One of the most problematic areas is the influence of the physical and mechanical characteristics of the stationary layer of crushed cotton stalks on the hydrodynamics of filtration drying. In the course of research, methods of physical and mathematical modeling are used. Sieve analysis is used to determine the granulometric composition of the polydisperse mixture of crushed cotton stalks. The granulometric composition of the crushed stalks of cotton is determined and the graphical dependence of the percentage of each fraction is presented. The hydrodynamics of gas flow filtration through a stationary layer of crushed cotton stalks are experimentally investigated, and a graphical dependence of pressure losses on the fictitious rate of gas flow filtration is presented. It is found that pressure losses in the stationary layer of crushed cotton stalks are parabolic, which indicates the influence of both inertial and viscous components on pressure losses. The unknown coefficients of the modified Ergun equation are determined on the basis of experimental data. The correlation dependence between the experimental and theoretically calculated values is presented and it is shown that the maximum relative error is 9.6 %, which is quite acceptable for practical calculations. The results of experimental studies are also presented in the form of a graphical dependence of the Euler number on the Reynolds number. Based on the generalization of the experimental data, the calculated dependences are obtained in the form of dimensionless complexes, which describe the hydrodynamics of the gas flow filtration through a stationary layer of crushed cotton stalks. This makes it possible to predict the energy costs for creating a differential pressure, with an accuracy sufficient for practical calculations. The ratio of the experimental values of pressure losses to the theoretically calculated ones, depending on the Reynolds number, is graphically presented. It is shown that the maximum relative error does not exceed 8 %. The proposed generalizations of experimental data will make it possible to determine the energy consumption for creating a pressure drop at the design stage of the drying equipment, as well as to calculate the optimal process parameters and predict its economic feasibility.

Determination of qualitative characteristics of soybean and rapeseed oil by infrared spectroscopy

The article presents results of the study of soybean and rapeseed vegetable oils’ qualitative composition dependence on the degree of raw materials grinding obtained by extraction in a stationary layer in a Soxhlet apparatus using methylene chloride as a solvent. A number of experiments were performed to determine the optical properties of oil by infrared spectroscopy. The absorption spectra for different oil samples are present in the article. The obtained results were compared with previous refractometric and UV-Vis spectroscopy studies.

Hydro-catalytic isomerization of light gasoline fraction of Zhanazhol field’s oil

The purpose of the present work is to show that light straight-run gasoline fraction can be used as feedstock for hydro-catalytic isomerization process, and the isomerized product can serve as a component for obtaining pure ecological commercial gasoline brand Euro-4 and Euro-5. Transformation of n-alkanes of Zhanazhol oil’s light gasoline fraction with boiling temperature 180°C was studied. Isomerization was carried out in a flow unit with a stationary layer of modified sample of industrial aluminum-platinum catalyst at 200-300°C and 2.0-4.0 MPa, with volume feed rate of 1.0-3.0 h-1 and circulation ratio of hydrogen containing gas circulation 1000-1500 m3/m3 of catalyst feed. Light gasoline fraction are subjected to a number of chemical transformations: n-paraffins isomerization, five-membered and six-membered cycloalkanes dehydroisomerization and hydrocracking. n-Alkanes are isomerized in iso-alkanes, naphthenic hydrocarbons are first subjected to hydrocracking with opening the cycle and forming n-alkanes, which are then isomerized into iso-alkanes. Thus, the reaction products contain isopentane, 2,3-dimethylbutane with octane number 92 and 104 correspondingly, and other iso-paraffinic hydrocarbons that lead to raise of gasoline octane number. By study of individual hydrocarbon composition of feedstock and isomerizate it is possible to establish some regularities hydrocarbons in the process of hydro-catalytic isomerization of light gasoline fraction.

MECHANISM OF FILTRATION DRYING OF ORGANIC MATERIALS OF FIBROUS STRUCTURE AND RESULTS OF RESEARCH OF EXTERNAL HEAT EXCHANGE

One of the high-intensity methods for removing both free and bound moisture is filtration drying. This is due to the fact that during filtration drying, the heat agent is filtered through the porous structure of the wet material, which is placed on the perforated partition in the direction "wet material–perforated partition". The velocity of the heat agent in the pores and channels of a stationary layer of wet material determines the thickness of the boundary layer (hydrodynamic, thermal, and diffusion) and, accordingly, the values of the heat and mass transfer coefficients. In addition, the surface of heat and mass transfer is the total surface of the pores and channels through which the heat agent is filtered. The filtration rate of the heat agent is determined based on technical and economic considerations, given that its increase affects the growth of pressure loss. Moreover, the actual speed of the heat agent relative to the layer elements is much higher than in the case of drying by any other methods (in a fluidized bed, during drying in pneumatic transport dryers, etc.). Large heat and mass transfer surfaces and the speed of the heat agent in the pores and channels of the stationary layer of wet material provide high heat and mass transfer coefficients and, accordingly, the intensity of filtration drying. This article presents the results of the study of external heat exchange between the heat agent and dry particles of organic materials of fibrous structure, in particular raw cotton and its stems, and the mechanism of filtration drying.

Supporting Multiple Smart-City Applications based on MUSANet, a Common IoMT Middleware

The MUSANet system is a three-tier middleware for smart cities implemented using InterSCity, ContextNet, and Mobile-Hub. In order to decentralize processing from the cloud, the system includes stationary layer processing in the fog and collection of mobile data in the edge. In this article, we explore the flexibility and decoupling offered by MUSANet. We present two different applications for smart cities and discuss how they can be implemented in MUSANet, showing that, using the basic infrastructure, we can build new applications without interfering in existing ones due to the low coupling between the entities that make up the tiers of MUSANet. A third application illustrates how the distribution of data processing among MUSANet layers can help reduce the network load, preserving energy.

Modelling of a hybrid culture system with a stationary layer of liquid perfluorochemical applied as oxygen carrier

A mathematical model of a hybrid culture system supported with a stationary layer of liquid perfluorochemical (PFC) as a source of O2 for cells which grow in the aqueous phase of culture medium has been developed and discussed. The two-substrate Monod kinetics without inhibition effects, i.e. the Tsao-Hanson equation, has been assumed to characterise the biomass growth. The Damköhler number which relates the growth rate to the mass transfer effects has been used to appraise the regime (i.e. diffusion-limited or kinetics) of the whole process. The proposed model predicted accurately previously published data on the submerged batch cultures of Nicotiana tabacum BY-2 heterotrophic cells performed in a culture system supported with a stationary layer of hydrophobic perfluorodecalin as a liquid O2 carrier. Estimated values of the parameters of the model showed that the process proceeded in the kinetics regime and the growth kinetics, not the effects of the mass transfer between aqueous phase and liquid PFC, had essential influence on the growth of biomass.

The effects of surface tension on the initial development of a free surface adjacent to an accelerated plate

When a vertical rigid plate is uniformly accelerated horizontally from rest into an initially stationary layer of inviscid incompressible fluid, the free surface will undergo a deformation in the locality of the contact point. This deformation of the free surface will, in the early stages, cause a jet to rise up the plate. An understanding of the local structure of the free surface in the early stages of motion is vital in many situations, and has been developed in detail by King & Needham (J. Fluid Mech., vol. 268, 1994, pp. 89–101). In this work we consider the effects of introducing weak surface tension, characterized by the inverse Weber number $\mathscr{W}$, into the problem considered by King & Needham. Our approach is based upon matched asymptotic expansions as $\mathscr{W}\rightarrow 0$. It is found that four asymptotic regions are needed to describe the problem. The three largest regions have analytical solutions, whilst a numerical method based on finite differences is used to solve the time-dependent harmonic boundary value problem in the last region. Our results identify the local structure of the jet near the vicinity of the contact point, and we highlight a number of key features, including the height of this jet as well as its thickness and strength. We also present some preliminary experimental results that capture the spatial structure near the contact point, and we then show promising comparisons with the theoretical results obtained within this paper.