Experimental-Mathematical Modeling of Surface Moisture Removal from Pre-Moistened Seeds

The cause of much damages in buildings, particularly in old buildings, is a direct or indirect consequence of moisture. For diagnosis of moisture in building materials it is necessary to perform remote measurements non-destructively with high selectivity. The method should be able to locate large areas with excessive moisture. For this presentation of the problem we developed the amplitude sensitive modulation thermography. This method utilizes the absorption behaviour of water in the wavelength of 1 .94 zm and a reference wavelength band at 1 .0 rim. To detect only this two wavelength bands without the influence ofleaking radiation, a modulated illumination is used. For a better comparability and an elimination of measuring effects we generate from the reference- and the measuring effect wavelength band a surface moisture image. With a preliminary calibration in laboratory the quantitative detection of surface moisture is achieved. The results of this investigation eliminate the influence of leaking radiation, geometric and surface conditions effects by reducing emission behaviour of the surface. At the moment the measurements present a trend to measure the moisture in different materials without a material characteristic dependence.

The article provides a substantiation of the conceptual model of the production process of special forms of dumplings. It is the first stage in the development of a model of this process as a control object. The purpose of which is to form an objective basis for the development of an effective system for automatic process control. The development of the conceptual model presupposes the specification and description of the properties of control channels and acting disturbances to the level of their mathematical model, which can be implemented in a simulation environment. Problems of identification of the mathematical model of the process of the production of dumplings, i. e. obtaining a mathematical description of processes based on the results of its purposeful experimental research, due to its complexity as a control object.The experimental approach, in this case, gives much more reliable results on the properties of the process. An attempt to obtain such general properties on the basis of experimental data would inevitably lead to the need for very complex and lengthy multifactorial experiments and nontrivial procedures for their processing. But this will leave open the question of the adequacy of the model for those conditions of the process and types of raw materials that were not covered by the experiments. Fundamentally important is the fact that the mathematical model of the process is developed as a model of the control object.Model can be used in two ways. This is due to the fact that in the closed circuits of the SAC, the discrepancy between the models can be considered as a manifestation of uncontrolled coordinate and parametric disturbances. It is in conditions of this kind of disturbances that the SAC must fulfill its functional purpose. The developed mathematical model of the production process of special forms of dumplings will be used by us only in the direction, when it is of great importance not so much quantitative as its qualitative correspondence to the original object.

The underground coal gasification is a continually evolving technology, which converts coal to calorific gas. There are many important parameters in this technology, which are difficult to measure. These parameters include the underground cavity growth, amount gasified coal, and the leakage of input and output gaseous components into the surrounding layers during the coal gasification process. Mathematical modeling of this process is one of the possible alternatives for determining these unknown parameters. In this paper, the structure of the mathematical model of laboratory underground coal gasification process from the material balance aspect is presented. The material balance consists of mass components entering and leaving from the UCG process. The paper shows a material balance in the form of a general mass balance and atomic species balance. The material balance was testing by six UCG laboratory experiments, which were realized in two ex-situ reactors.

Coleoptile surface cuticle of barley is involved in survival and penetration of Blumeria graminis

Abstract. Boreal upland forests are generally considered methane (CH4) sinks due to the predominance of CH4 oxidizing bacteria over the methanogenic archaea. However, boreal upland forests can temporarily act as CH4 sources during wet seasons or years. From a landscape perspective and in annual terms, this source can be significant as weather conditions may cause flooding, which can last a considerable proportion of the active season and because often, the forest coverage within a typical boreal catchment is much higher than that of wetlands. Processes and conditions which change mineral soils from acting as a weak sink to a strong source are not well understood. We measured soil CH4 fluxes from 20 different points from regularly irrigated and control plots during two growing seasons. We also estimated potential CH4 production and oxidation rates in different soil layers and performed a laboratory experiment, where soil microcosms were subjected to different moisture levels and glucose addition simulating the fresh labile carbon (C) source from root exudates. The aim was to find the key controlling factors and conditions for boreal upland soil CH4 production. Probably due to long dry periods in both summers, we did not find occasions of CH4 production following the excess irrigation, with one exception in July 2019 with emission of 18 200 µg CH4 m−2 h−1. Otherwise, the soil was always a CH4 sink (median CH4 uptake rate of 260–290 and 150–170 µg CH4 m−2 h−1, in control and irrigated plots, respectively). The median soil CH4 uptake rates at the irrigated plot were 88 % and 50 % lower than at the control plot in 2018 and 2019, respectively. Potential CH4 production rates were highest in the organic layer (0.2–0.6 nmol CH4 g−1 d−1), but some production was also observed in the leaching layer, whereas in other soil layers, the rates were negligible. Potential CH4 oxidation rates varied mainly within 10–40 nmol CH4 g−1 d−1, except in deep soil and the organic layer in 2019, where potential oxidation rates were almost zero. The laboratory experiment revealed that high soil moisture alone does not turn upland forest soil into a CH4 source. However, a simple C source, e.g., substrates coming from root exudates with high moisture, switched the soil into a CH4 source. Our unique study provides new insights into the processes and controlling factors on CH4 production and oxidation, and the resulting net efflux that should be incorporated in process models describing global CH4 cycling.

This monograph reviews and examines the theoretical background and literature published so far for the mathematical modeling and simulation of the rubber vulcanization process. This work has been organized in the following way. First, an introductory section is given, which provides a brief overview of the topic and the aim and scope of the paper. Then, it goes on to give a comprehensive overview of the historical background up to present state. It is tried here not only to consider rubber vulcanization process, but the curing of other thermoset polymers are examined. The third section presents the mathematical modeling of the curing process and focuses on four key items including heat transfer governing equations, thermal properties of rubbers and their measurements, kinetics of the curing reaction and solution methodology. In this part, the details of the solution methods for the governing equations and also different types of kinetics of curing reactions are studied. The fourth section presents the findings of some research works carried out in this field, which is divided into two subsections as tires and non-tires applications. A brief summary on the presented work and some suggestions for future research are introduced in the fifth section, and finally the bibliography of this review is given.

The paper deals with the problem of mathematical modeling of the process of thermochemical destruction using the theory of graphs. To synthesize a mathematical model, the Markov chain is used. For the formalization of the model a matrix-graph method of coding is used. It is proposed to consider the process of destruction as a random process, under which the state of the system changes, characterized by the proportion of macromolecules in each fraction of the molecular mass distribution. The intensities of transitions from state to state characterize the corresponding rates of destruction processes for each fraction of the molecular weight distribution (MWD). The processes of crosslinking and polymerization in this work have been neglected, and it is accepted that there is a probability of transition from any state with a lower order index (corresponding to fractions with higher molecular weights) to any state with a higher index (corresponding fractions with lower molecular weights). A computational formula is presented for estimating the number of arcs and model parameters from a given number of fractions of the molecular weight distribution of the polymer. An example of coding in a matrix form of a graph model of the process of degradation of polybutadiene in solution for the case of six fractions of the molecular weight distribution is shown. As the simulation environment, the interactive graphical simulation environment of MathWorks Simulink is used. To evaluate the parameters of the mathematical model, experimental studies of the degradation of polybutadiene in solution were carried out. The chromatography of the polybutadiene solution was used as the initial data for the estimation of the MWD polymer. The considered matrix-graph representation of the structure of the mathematical model of the polymer destruction process makes it possible to simplify the compilation of the model and its software implementation in the case of a large number of vertices of the graph describing the process of destruction

A complete mathematical modeling of the technological process of manufacturing vinyl acetate monomer by vapor-phase method has been implemented. The model is partial differential equations of the material and energy balance and catalyst aging. An algorithm for an integrated equation based on the second-order Gregg-Bulirsh-Shter rectangle symbol has been developed. The error in modeling the process is equal (CH3COOCH=CH2) ± 5.4% rel. for the target matter, and (CO2) ± 6.4% rel. for the secondary substance The kinetic coefficients of differential equations, namely the pre-exponential factors and the activation energy have been refined. The obtained data of the modeling of the vapor-phase manufacturing process of vinyl acetate are shown in the form of tables and graphic three-dimensional dependencies of quality indicators on technological parameters.

Fabrication of free-standing nanoparticle-fused nanosheets and their hetero-modification using sacrificial film

A significant proportion of natural gas (NG) is produced in cold climates, where conditions are relevant to the formation of gas hydrates in raw gas stream. Methanol is often used as an effective inhibitor of hydrate formation. Further conditioning of NG includes dehydration, and the most common process of water vapor removal from NG is absorption. Absorption also provides removal of methanol vapors, which allows it reuse. The membrane method of natural gas dehydration is considered as a promising alternative; however, the study of methanol recovery by the membrane method, simultaneously to the dehydration of NG, has not been carried out previously. In addition, data on methanol vapor transfer in gas separation polymer membranes are almost absent in the literature. This paper evaluates the permeability coefficients of methanol vapors for several polymer materials, which are applied to the production of industrial membranes (PPO, PSf, CA). Mathematical modeling of the membrane process of NG dehydration with simultaneous recovery of methanol was performed. The dependencies of membrane area, methanol recovery and energy consumption for methane recycling and recompression on the process parameters are calculated. Obtained data show that the recovery of methanol during membrane dehydration of NG varies in the range 57–95%. The lowest values of membrane area and specific energy consumption were found for PPO based membrane.

In this work, a mathematical model of the laser material processing based upon the heat conduction equation is developed and solved by the finite element method. In this study, the process model is assumed to be in the quasi-steady state and laser beam power distribution to follow Gaussian distribution to get the best simulation of the temperature distribution. The convection effects are included in the two dimensional model. The keyhole concept is used to obtain a better insight into the process. Finite element method is employed to solve the non-dimensionalized governing conduction equation. The effects of the incident laser power, the laser beam diameter, the shielding gas velocity, the beam speed and different type of material are investigated based upon the above model. The laser beam power, laser beam diameter, the moving speed and the type of material are found to have more significant effects in the process. The shielding gas (i.e. the convection) velocity has little influence on the temperature distribution associated with the process. The results from the two-dimensional finite element model are compared with the temperature profiles obtained using a 3-dimensional finite-difference model.In this work, a mathematical model of the laser material processing based upon the heat conduction equation is developed and solved by the finite element method. In this study, the process model is assumed to be in the quasi-steady state and laser beam power distribution to follow Gaussian distribution to get the best simulation of the temperature distribution. The convection effects are included in the two dimensional model. The keyhole concept is used to obtain a better insight into the process. Finite element method is employed to solve the non-dimensionalized governing conduction equation. The effects of the incident laser power, the laser beam diameter, the shielding gas velocity, the beam speed and different type of material are investigated based upon the above model. The laser beam power, laser beam diameter, the moving speed and the type of material are found to have more significant effects in the process. The shielding gas (i.e. the convection) velocity has little influence on the temperature d...

Application of a carbon nanotube (CNT) sheet as a current collector for all-solid-state lithium batteries

Model-to-model: Comparison of mathematical process models of lipase catalysed biodiesel production in a microreactor

<b> </b><b> </b>The decision of contact problems taking into account the wear process of nano- and macro-surfaces of sliding bearings of piston machines has great importance for forecasting their durability. Wear processes of the surfaces create tension change on the contact area. The paper focuses on the mathematical modelling of the wear process of the insert of sliding bearings made of self-lubricating material, taking into account contact deformation using the elements of nanomechanics. The differential equation of a contact condition of this bearing is deduced and solved. A method is developed to define the intensity of the wear of the insert of sliding bearings made of self-lubricating material. There is determined the expression for definition of dimensionless parameters of speed of wear of the surface of the insert of sliding bearing.<SUB> </SUB>The method developed for estimation of intensity of the wear process allows us to operate this process and to find the optimum value of wear of mobile couplings of sliding bearings.

An influence of the ultrasound beam on the process, dissolution of solids in liquid solvents is considered: influence of frequency, intensity, velocity of acoustic vibrations, cavitation and acoustic flows on mass transfer process. Experimental researches show that the intensification of dissolution process of solids in liquid solvents under action of ultrasound is influenced by acoustic flows, microflows and under influence of cavitation bubbles. Development of new efficient equipment for solution requires the development of calculation methods of dissolution processes of solids in liquid solvents under conditions of ultrasonic irradiation. Such methods should take into account the characteristics of ultrasonic generators, irradiation frequency of ultrasonic vibrations, power and intensity of ultrasonic vibrations. Mathematical model of dissolution process of the granule is constructed. It identifies the change of size of the granule over time under influence of the source of ultrasonic irradiation. Mathematical model consists of three differential equations used to calculate depending on the ratio of the granule size and the maximum turbulence scale of acoustic flows and for cavitation. The mathematical model will enable use in conducting numerous studies as a basis of equipment calculation methods for dissolution process of granular material.