Parameter Identification of the Fractional-Order Mathematical Model for Convective Mass Transfer in a Porous Medium.

Fractional calculus is an essential tool in studying new phenomena in hydromechanics and heat and mass transfer, particularly anomalous hydromechanical advection-dispersion considering the fractal nature of the porous medium. They are valuable in solving the urgent problem of convective mass transfer in a porous medium (e.g., membranes, filters, nozzles, convective coolers, vibrational prillers, and so on). Its solution allows for improving chemical engineering and technology workflows, refining process models for obtaining porous granular materials, realizing the convective cooling of granular and grain materials, and ensuring the corresponding apparatuses' environmental safety. The article aims to develop a reliable convective mass transfer model for a porous medium and proposes a practical approach for its parameter identification. As a result, a general scientific and methodological approach to parameter identification of the fractional convective mass transfer model in a porous medium was proposed based on available experimental data. It mainly used Riemann-Liouville fractional time and coordinate derivatives. The comprehensive application of the Laplace obtained the corresponding general solution transform with respect to time and a coordinate, the Mittag-Leffler function, and specialized functions. Different partial solutions in various application case studies proved this solution. Moreover, the algorithm for practically implementing the developed approach was proposed to evaluate parameters for the considered model by evaluation data. It was reduced to the two-parameter model and justified by the available experimental data.

Monitoring of Measuring Devices Using a Programmable Logic Controller and a Dedicated Desktop Application.

An appropriate control and measurement system is one of the elements that allows for the safe and effective operation of a technological installation. Such a system may have a diverse structure that corresponds to the expectations and needs of its user. The devices of various manufacturers, including PLC (programmable logic controllers), can be used as a source of measurement data. This enables flexible measurement-control installations, which are adapted to the technological installations, to be built. This paper presents a system, which was created by the authors, for monitoring the temperature, pressure and flow rate of fluids. It uses the operational and IT properties of the PLC and is adapted to an existing installation on the test stand for multiphase spraying processes. In addition, as a part of the research, an application written in Python language, which allows collected data to be displayed, stored and exported, was implemented.

Analysis of Statistically Predicted Rate Constants for Pyrolysis of High-Density Plastic Using R Software.

The surge in plastic waste production has forced researchers to work on practically feasible recovery processes. Pyrolysis is a promising and intriguing option for the recycling of plastic waste. Developing a model that simulates the pyrolysis of high-density polyethylene (HDPE) as the most common polymer is important in determining the impact of operational parameters on system behavior. The type and amount of primary products of pyrolysis, such as oil, gas, and waxes, can be predicted statistically using a multiple linear regression model (MLRM) in R software. To the best of our knowledge, the statistical estimation of kinetic rate constants for pyrolysis of high-density plastic through MLRM analysis using R software has never been reported in the literature. In this study, the temperature-dependent rate constants were fixed experimentally at 420 °C. The rate constants with differences of 0.02, 0.03, and 0.04 from empirically set values were analyzed for pyrolysis of HDPE using MLRM in R software. The added variable plots, scatter plots, and 3D plots demonstrated a good correlation between the dependent and predictor variables. The possible changes in the final products were also analyzed by applying a second-order differential equation solver (SODES) in MATLAB version R2020a. The outcomes of experimentally fixed-rate constants revealed an oil yield of 73% to 74%. The oil yield increased to 78% with a difference of 0.03 from the experimentally fixed rate constants, but light wax, heavy wax, and carbon black decreased. The increased oil and gas yield with reduced byproducts verifies the high significance of the conducted statistical analysis. The statistically predicted kinetic rate constants can be used to enhance the oil yield at an industrial scale.

A review of flocculants as an efficient method for increasing the efficiency of municipal sludge dewatering: Mechanisms, performances, influencing factors and perspectives.

Mechanical sludge dewatering is one of the stages of the municipal wastewater treatment process, which allows the amount of generated sludge and the cost of its transport and management to be reduced. Achieving a high degree of dewatering is possible thanks to the use of flocculation technology. The article presents issues related to the theory of flocculation, sewage sludge, and its dewatering. The main mechanisms of flocculation, the kinetics of the process, the division of flocculants, and flocculation in dual systems are discussed. The influence of particular parameters on the efficiency of flocculation and the dewatering of sewage sludge was analyed. The assessed parameters are: pH, the presence of salt, the mixing process, the structure and ionicity of chains, and the dose. The results of experimental studies on the dewatering of various types of sludge were compared. The literature review included in the paper helps to better understand the process of flocculation and sludge dewatering, and presents the progress to date and the possible directions for further development in this field.

Spray curtains as devices for surface spraying during the SARS-CoV-2 pandemic.

Counteracting the spread of the SARS-CoV-2 virus is a current and important problem. A crucial issue in this area is the disinfection of various surfaces, as well as the air itself. For this purpose, devices such as foggers, which have different designs, are used. The appropriate size of droplets and their distribution determines the effectiveness of disinfectants. The paper presents droplet size distributions and characteristic mean droplet diameters, which are obtained with the use of a conical pressure-swirl atomizer. For the purpose of the analysis, the laser diffraction method was used. The influence of gas pressure and the distance from the atomizer's orifice on the spray angle and the distance between the nozzles on the spray curtain was also demonstrated.

Flow Rate Control by Means of Flow Meter and PLC Controller.

This paper presents a design of a flow meter based on a programmable logic controller (PLC). The new construction of a flow meter controlled by PLC increases the possibilities for the control and automation of fluid flow. Additionally, the didactic potential of the use of simple automation in the form of a programmable logic controller was considered. A device enabling the measurement of fluid flow rate based on a PLC controller was designed, constructed, and tested. The choice of device was the Gems Sensors FT-210 series turbine flow sensor, which is characterized by low purchase and maintenance costs. The properties and the chemical resistance of polyamide-12, the material the sensor is made of, make it possible to test the flow of various types of fluids. As part of the work, an algorithm and a program controlling the device was developed based on the APB Soft software, enabling the accurate reading of the number of impulses sent by the turbine flow sensor. The results of the designed flow meter were compared with the results obtained for the Krohne VA-40 high accuracy rotameter.

Evaluation of the Possibility of Using 1.4462 and 1.4501 Steel as a Construction Material for Apparatus Operating at an Increased Temperature and with Corrosive Factors.

The objective of this study was to determine the requirements for steels used as construction materials for chemical apparatus operating at an elevated temperature and to correlate them with the properties of the tested steels. The experimental part examined the influence of the annealing process on the structure and properties of X2CrNiMoN22-5-3 (1.4462) and X2CrNiMoCuWN25-7-4 (1.4501) steel. Heat treatment was carried out on the tested samples at a temperature of 600 °C and 800 °C. Changes were observed after the indicated time intervals of 250 and 500 h. In order to determine the differences between the initial state and after individual annealing stages, metallographic specimens were performed, the structure was analyzed using an optical microscope and the micro-hardness was measured using the Vickers method. Potentiostatic tests of the samples were carried out to assess the influence of thermal process parameters on the electrochemical properties of the passive layer. An increase in the hardness of the samples was observed with increasing temperature and annealing time, the disappearance of magnetic properties for both samples after annealing at the temperature of 800 °C, as well as a significant deterioration in corrosion resistance in the case of treatment at a higher temperature.

The analysis of pneumatic atomization of Newtonian and non-Newtonian fluids for different medical nebulizers.

OBJECTIVE: The article contains results of the experimental studies on atomization process of inhaled drugs and aqueous solutions of glycerol with aqueous solutions of glycerol polyacrylamide (Rokrysol WF1) in pneumatic nebulizers. In experiments, the different concentration of aqueous solutions of glycerol polyacrylamide have been tested. In addition, the effect of nebulizer design on atomization process has been determined. The one of the main elements of medical pneumatic nebulizer is nebulizer cup. SIGNIFICANCE: The experiment with this scope is new and is very important from the point of view of aerosol therapy. METHODS: The results have been obtained by the use of the digital microphotography technique. In order to determine a physicochemical properties of tested liquids, a rheological measurements and measurements of the surface tension were carried out. RESULTS: The differences between characteristics of aerosol for the liquids have been observed. The analysis of the droplets size distributions shows that the different diameters of droplets for Newtonian and non-Newtonian fluids have been formed during atomization in pneumatic nebulizers equipped with different nebulizer cups. The effect of the mouthpiece location on the droplets diameters has been shown. CONCLUSIONS: Precise design of nebulizer and nebulizer cups, and also physicochemical properties of atomized liquids are of high importance in order to the effectiveness of drug delivery to patient's respiratory tracts.

The modified swirl sedimentation tanks for water purification.

This paper discusses design, evaluation, and application for the use of swirl/vortex technologies as liquid purification system. A study was performed using modified swirl sedimentation tanks. The vortex separators (OW, OWK, OWR and OWKR) have been studied under laboratory conditions at liquid flow rate from 2.8⋅10-5 to 5.1⋅10-4 [m3/s]. The pressure drop and the efficiency of purification of liquid stream were analyzed. The suspended particles of different diameters were successfully removed from liquid with the application of swirl chambers of proposed constructions. It was found that damming of liquid in the tank increases alongside liquid stream at the inlet and depends on the tank construction. The efficiency of the sedimentation tanks increases alongside the diameters of solid particles and decrease in the liquid flow rate. The best construction proved to be the OWR sedimentation tank due to smallest liquid damming, even at high flow rates, and the highest efficiency of the purification liquid stream for solid particles of the smallest diameter. The proposed solution is an alternative to the classical constructions of sedimentation tanks.