scholarly journals Determination of drying behaviour in industrial type convectional dryer and mathematical modelling

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 1935-1950 ◽  
Author(s):  
Ahmet Akan ◽  
Derya Ozkan
Keyword(s):  
Experimental Study ◽  
Mathematical Modelling ◽  
Diffusion Model ◽  
Diffusion Coefficients ◽  
Experimental Studies ◽  
Activation Energies ◽  
Second Law ◽  
Hot Air ◽  
Drying Behaviour

In this study, the performance of a stenter (ram machine) that enables the drying of textile products with hot air is theoretically modelled with a diffusion model derived from Fick?s second law. The experimental study was conducted in a 10 chamber stenter with three different drying temperatures (110-130-150?C) and three different fabric speeds (10-20-30 m per minute.) by using a fabric consisting of 95% cotton + 5% lycra. The drying behaviour of the dryer was determined by utilizing the data obtained from the studies. With the help of the utilized model, the values of diffusion coefficients and activation energies were obtained, the conformity of data between the model and the experimental studies were compared by using regres

scholarly journals Migration of mineral oil in elastomers

2021 ◽  
Author(s):  
Tobias Förster ◽  
Artur Blivernitz
Keyword(s):  
Diffusion Coefficients ◽  
Mineral Oil ◽  
Activation Energies ◽  
Concentration Profiles ◽  
Small Reservoir ◽  
Experimental Procedure ◽  
Mineral Oils ◽  
The Absolute ◽  
Suitable Measure

AbstractThis work describes a newly introduced experimental procedure to quantify the diffusion progress of mineral oils locally resolved in NBR. Diffusion of reference oils IRM 901, IRM 902 and IRM 903 in NBR with various acrylonitrile contents was investigated. Classical sorption experiments were performed as a basic characterization and compared to the newly introduced method. Here, elastomer specimens are only being dipped with the bottom in a relatively small reservoir of mineral oil. This provides a determination of locally resolved concentration profiles of mineral oils, and the calculation of diffusion coefficients. These diffusion coefficients follow the same trends like those determined via sorption experiments. Despite differences in the absolute numbers, activation energies of diffusion can be applied as a suitable measure for the compatibility of elastomers and fluids.

Werkstoffaufbau und diffusiver Stofftransport aufgezeigt an ausgewählten Beispielen / Material structure and diffusive mass transport as pointed out by means of selected examples

2000 ◽  
Vol 6 (4) ◽  
pp. 429-450
Author(s):  
R. Kriegel ◽  
A. Buchwald ◽  
Ch. Kaps
Keyword(s):  
Mass Transport ◽  
Diffusion Coefficients ◽  
Transport Mechanism ◽  
Diffusion Models ◽  
Second Law ◽  
Material Structure ◽  
Ion Diffusion ◽  
Oxygen Ion ◽  
Oxygen Ion Diffusion

Abstract The diffusive mass transport in materials is above all determined by the material structure. The experimental determination of diffusion coefficients is based on diffusion models, which results from special mathematical solutions of Fick's second law and its corresponding boundary conditions. The general usefulness of these diffusion models will be described using some examples, e. g. the diffusion of deteriorating salts in masonry materials, the oxygen ion diffusion in mixed conducting ceramics and the cation exchange in single crystals. The measurement of the diffusion coefficients results in a better comprehension of the transport mechanism as well as of the "morphology" of the transport medium, which allows to optimize the conditions of the mass transport and the material structure and composition, respectively.

scholarly journals The Influence of the Shape of Granite on the Heat Storage Process in a Rock Bed

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5662 ◽  
Author(s):  
Magdalena Nemś ◽  
Artur Nemś ◽  
Kamila Gębarowska
Keyword(s):  
Spherical Geometry ◽  
Experimental Tests ◽  
Second Law ◽  
Storage Process ◽  
Advantages And Disadvantages ◽  
Hot Air ◽  
Local Material ◽  
Rock Bed ◽  
Short Time

Granite is one of those materials that due to its thermal parameters is used as a filling for storage beds, including high-temperature ones. The article analyzes local material that was extracted in Strzegom, Poland. The purpose of the paper is the assessment of storage material with regard to its cooperation with a heat source that is available for a short time, e.g., a solar installation. Three different shapes of granite material were tested: rock, cube and sphere. Each shape has its advantages and disadvantages, which are associated with economic and strength aspects. The article presents experimental tests of the material, which were conducted in order to determine the efficiency of the charging process. The results show that rock-shaped granite filling elements are characterized with the best parameters during the charging process, and that they obtained the highest first- and second-law efficiency in the entire tested range of inlet air temperature and flow rate. The efficiency of the cube-shaped granite was lower than the sphere-shaped granite. This means that the efficiency does not directly depend on the coefficient of sphericity of the elements that fill the storage bed. The determination of the second law efficiency showed that the highest use of energy supplied with hot air occurs after 1 h of charging the accumulator in the case of all the analyzed geometries. At the end of the paper, the influence of the obtained results on the process of modelling the charging of a storage bed filled with elements of non-spherical geometry is also discussed.

Chronoamperometric Determination of Diffusion Coefficients for Borohydride Anions in Sodium Hydroxide Solutions

2008 ◽  
Vol 273-276 ◽  
pp. 583-589 ◽  
Author(s):  
Diogo M.F. Santos ◽  
César A.C. Sequeira
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Borohydride ◽  
Diffusion Coefficients ◽  
Activation Energies ◽  
Disc Electrode ◽  
Estimated Parameters ◽  
Borohydride Oxidation

Chronoamperometry is carried out with a Au disc electrode in alkaline sodium borohydride solutions of varying concentrations and temperatures. By selecting conditions for which the borohydride oxidation is controlled by diffusion, it was possible to deduce diffusion coefficients and activation energies for borohydride concentrations ranging from 0.03 M to 0.12 M, and temperatures ranging from 25 to 65 °C. The estimated parameters were compared with other values reported in the open literature.

Diffusion calculations for the 80-K-to-110-K Bi(Pb)SrCaCuO superconducting phase transformation

1999 ◽  
Vol 14 (11) ◽  
pp. 4143-4147 ◽  
Author(s):  
Wen Zhu ◽  
Chu Kun Kuo ◽  
Patrick S. Nicholson
Keyword(s):  
Phase Transformation ◽  
Diffusion Model ◽  
Chemical Transformation ◽  
Diffusion Coefficients ◽  
Activation Energies ◽  
Superconducting Phase ◽  
Cation Diffusion ◽  
High Activation ◽  
Phase Diffusion ◽  
Diffusion Rates

A diffusion model is proposed to fit the measured chemical-transformation rates of the Bi(Pb)CaCuSrO 80-K phase to 110-K phase. Diffusion coefficients and activation energies in PO2 = 0.08 and 0.21 atm are reported. The low diffusion rates and high activation energies suggest cation diffusion controls the transformation.

Research of Operational Properties of Household Fabrics for Production of Protective Masks

2021 ◽  
Vol 1038 ◽  
pp. 221-232
Author(s):  
Serhii Cheberiachko ◽  
Ivan Knysh ◽  
Dmytro Pustovoi ◽  
Olena Sharovatova
Keyword(s):  
Experimental Study ◽  
Protective Action ◽  
Experimental Studies ◽  
Breathing Resistance ◽  
Paraffin Oil ◽  
Two Samples ◽  
Physiological Impact ◽  
The Relationship ◽  
Penetration Coefficient

Experimental studies have been conducted to determine the operational properties of fabrics used for the manufacture of protective masks. For the experimental study, 22 different fabrics were used, which are available in everyday life. Determination of the operational properties was carried out according to three indicators: the penetration coefficient of the test aerosol, paraffin oil (filtering property), breathing resistance (ergonomic property), resistance to dusting (protective action period) in accordance with the requirements of DSTU EN 149-2017 standard. According to the results of the experimental study to determine the operational properties of fabrics: breathing resistance, penetration coefficient and resistance to dust, it was found that out of the twenty-two samples tested, only eight can be used for the manufacture of protective masks, since their characteristics are able to provide a sufficient level of protection from minimal physiological impact on human (wool, two-thread cloth, velor, tricotin, jersey, frieze and satin). Theoretical calculation of the operational properties of protective masks, which can be made of these fabrics, based on experimental data allowed to make their compliance with the first class of protection according to the requirements of DSTU EN 149-2017. The scientific novelty is to clarify the relationship between the operational properties of fabrics and the operational properties of protective masks.

scholarly journals EXPERIMENTAL DETERMINATION OF THE LEVEL OF INCIPIENT TURBULENCE IN THE WORKING PART OF THE T-1 WIND TUNNEL OF IVAN KOZHEDUB KHARKIV NATIONAL AIR FORCE UNIVERSITY

2021 ◽  
Vol 5 (2) ◽  
pp. 98-102
Author(s):  
Віталій Бездєльний ◽  
Сергій Шевченко ◽  
Ілля Грідасов
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Wind Tunnel ◽  
Experimental Determination ◽  
Air Force ◽  
Normal Condition ◽  
Aerodynamic Drag ◽  
Experimental Studies ◽  
The Subject

The subject of the article is to determine the level of incipient turbulence in the wind tunnel T-1 which is based on the method of measuring the pressure drop. The purpose is to experimentally determine the level of incipient turbulence in the working part of wind tunnel T-1 of Ivan Kozhedub Kharkiv National Air Force University in preparation for aerodynamic testing of aircraft models. Research methods: the method of pressure drop on the surface of the sphere by drainage. The following results of experimental determination of the level of incipient turbulence in the wind tunnel T-1 were obtained. It is established that the wind tunnel T-1 has a level of incipient turbulence 0,5…0,9 %, which corresponds to the normal condition for further experimental studies. Conclusions. According to the results of studies of the incipient turbulence in the wind tunnel T-1 by the method of pressure drop, the main dependences are obtained, and the incipient turbulence of the flow for the wooden sphere x = 0,9 %, and for the metal sphere x = 0,5 %, is determined. Determining the pressure distribution and aerodynamic drag does not involve measures to balance the aerodynamic scales and their certification, which determines the necessary role in the obtained reliable results of the experimental study, and this favors the drainage method.

scholarly journals Determination of working parameters of measure to ensure metrological research tribological characteristics of plain bearings

2017 ◽  
Vol 6 (2) ◽  
pp. 123-129
Author(s):  
Серебрянский ◽  
Aleksey Serebryanskiy
Keyword(s):  
Experimental Study ◽  
Experimental Studies ◽  
Design Parameters ◽  
Laboratory Equipment ◽  
The Real ◽  
Metrological Research ◽  
Real Size ◽  
Working Parameters ◽  
Conditions Of Work

The characteristics of plain bearings used in the industry are given in the article. The directions that increase their ser-vice life are defined. The need for experimental studies of bearing is justified, and laboratory equipment is offered. Experimental study of bearings is necessary to verify calculations and to determine the effect of changing some design parameters on their work as well. It is usually difficult or even impossible to experience the bearing in the real size and under conditions identical to real conditions of work.

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