Computational fluid dynamic analysis of corona virus patients breathing in an airplane

Effective ventilation systems are essential to control the transmission of airborne aerosol particles, such as the SARS-CoV-2 virus in aircraft cabins, which is a significant concern for people commuting by airplane. Validated computational fluid dynamic models are frequently and effectively used to investigate air distribution and pollutant transport. In this study, the effectiveness of different ventilation systems with varying outlet vent locations were computationally compared to determine the best ventilation system for minimizing the risk of airborne transmission. The cabin air conditioning system was optimized to determine how design variables (air inlet temperature, outlet valve width and location, and mass flow rate) affect output parameters, including particle residence time, age of air, and thermal comfort conditions. Inlet mass flow rate was observed to be an influential variable impacting all output parameters, especially on age of air, where it was the most influential. In contrast, the least effective variable was width of the outlet valve, which only affected the particle residence time. Also, Predicted Mean Vote and Predicted Percentage Dissatisfied indices were the most affected by air inlet temperature, which had an inverse relation, while the outlet valve location had the greatest effect on particle residence time. © 2023 Author(s).

Mass transfer effects on mucus fluid in the presence of chemical reaction

The mucus fluid vehicle is impacted by the synthetic response that changes the physical science of liquid due to the thickness of the bodily fluid. Additionally, various issues in the respiratory system might happen because of bodily fluid adequacy. A central point of transportation of immunizations to forestall COVID-19 is the concentration level expected during movement, stockpiling, and dispersion. The current review stated that mucus fluid transportation is restrained through magnetic force originating due to heat variation. Permeable channel over respiratory disease and chemicals due to mass reaction–diffusion variation. The bodily fluid development is surveyed by the force, energy, and diffusion condition influence of body powers because of attractive field, source of heat cause of thermal conduction, resistance due to disease chemical reaction cause of concentration profile. The nonlinear arrangement of incomplete differential conditions is addressed by the Laplace transform technique, and MATLAB programming outcomes are initiated for momentum, temperature, and diffusion fields and inferred that the bodily fluid stream decelerates due to magnetic force. The skin friction, Nusselt number, Sherwood number, and the microorganism's thickness are assessed and explained exhaustively. Furthermore, microorganisms are occupied in different elements to survey the mucus fluid mechanism. © 2022

A comprehensive review on the application of ultrasound for the preservation of fruits and vegetables

Ultrasound technology is a green and environment-friendly technology that rarely causes thermal damage to food products. In this review, we present an overview of the application of ultrasound technology for the dehydration of food products, including pre-treatments such as ultrasound, osmotic dehydration, and ultrasound-assisted osmotic dehydration. Dehydration promotes the preservation of food products and increases the shelf life of the food products by reducing water activity. In addition, the ultrasound-assisted drying of food products is highlighted. The influence of ultrasound and ultrasound-assisted osmotic dehydration parameters on drying kinetics and food quality is also discussed. The application of pre-treatments enhances the mass transfer rate, increases the drying rate and drying efficiency, reduces drying time, and helps to retain food properties such as texture and nutrition value. Generally, ultrasound and osmotic dehydration application decreases water activity, increases rehydration ability, improves product color, and reduces nutrient losses. To conclude, we have discussed the use of ultrasound applications for improving the quality and safety of produce before and after the drying process.

Determination of the Morphological Characteristics of Eight Types of Protective Face Masks and Respirators

Respiratory infections have arisen as a public health concern. The regulation of COVID-19 is based on knowledge of its transmission mechanism. Masks and respirators act as a physical barrier against respiratory droplets that enter through the nose and mouth, as well as droplets spat by sick persons. Textile masks (including 'do-it-yourself'), surgical (medical) masks and respirators are the three basic types of personal protection devices, covering the human face. The purpose of our work is to give a study on the morphological features of masks and respirators, which are widely accessible in Bulgarian shops and pharmacies, revealing their structure and differences between them. The results will be further used for the assessment of heat and mass transfer abilities of the masks/respirators, which are largely preconditioned by the masks' morphology. © 2022 IEEE.

The experimental study of dehumidification and regeneration processes in a fin and tube liquid desiccant system

Significant focus has been placed on improving Indoor Air Quality (IAQ) due to the emergence of the large-scale severe acute respiratory syndrome (SARS) virus epidemic in the air conditioning system of buildings. There is also a need for an adequate air ventilation system that balances energy needs with air quality. This led to the discovery of liquid desiccants which have the ability to enhance air quality and lower primary energy usage as an alternative to the standard air dehumidification technology. Therefore, this study was conducted to investigate the dehumidi-fication and regeneration processes in a Fin and tube liquid desiccant system. This involved flowing air horizontally while the ionic liquid flowed through the cooling or heating coil verti-cally downward to create a cross-flow fin and tube configuration. In the testing process, we ob-tained measurements of relative humidity and dry bulb temperature inlet and outlet from ducting by varying the input parameters. Moreover, the differential humidity ratio of the inlet and output process for the dehumidification and regeneration was observed to be essential for the dehu-midifier performance indices. The experimental result showed that the system absorbed a hu-midity ratio of 5.5 g/kg during the dehumidification process and released 10.7 g/kg during regeneration.

HEATQUIZ: AN OPEN-ACCESS FRAMEWORK FOR HEAT TRANSFER EDUCATION WITH GAME-BASED LEARNING ELEMENTS

Since 2017, HeatQuiz is developed as a tool for students in the subject of Heat and Mass Transfer to train their skills and strengthen their knowledge. The topics span from view factors to temperature distributions up to dimensionless numbers. With more that 800 questions, HeatQuiz provides a large variety of questions in it's database. Due to the COVID-19 pandemic and the obligation for social distancing HeatQuiz has evolved from a mobile teaching application with customized subject-specific question types to a tool that combines game-based elements with structured access to an open heat transfer lecture. Combining micro-lectures for the flipped-classroom concept and hundreds of quiz questions in a well structured learning environment is one of the main strengths. This article describes the learning path concept and how it is embedded in HeatQuiz. Secondly, a new question type will be introduced that is especially designed to practise the skill of developing energy balances based on a sketch of the control volume, defining all relevant fluxes, and finally defining the required boundary conditions. © 2022 Begell House Inc.. All rights reserved.

Polymer Membranes for Enthalpy Exchangers

A membrane-based enthalpy exchanger is a device used for heat and humidity recovery in ventilated buildings. The energy-saving potential of such a device is dependent on the parameters responsible for heat and moisture recovery. The trend is toward composite membranes, which are custom produced, and their parameters can be adjusted for a given application;therefore, the diffusion and sorption characteristics of such membranes are unknown. In order to obtain the values of the water vapor diffusivity of three investigated handmade membranes, a serial resistance model using a Field and Laboratory Emission Cell (FLEC) is proposed. Experiments were conducted to identify the resistance in each step of the moisture transfer process to extract the moisture diffusivity in the membranes. The calculated moisture diffusivities in the membranes were 8.99 × 10−12 (m2/s) for the membranes from cellulose acetate, 1.9 × 10−10 (m2/s) for the microporous PE/PUR membranes, and 1.53 × 10−11 (m2/s) for the PET/PUR microfibrous membranes. The obtained membrane diffusivities were then used in the proposed effectiveness-NTU-based model of an exchanger with a cross-flow arrangement to predict performance under various operating conditions. The results show that the highest latent effectiveness was found for the exchanger core made from the PE/PUR membrane and the lowest was for the one with the PE/PUR membrane core.

Mass Transfer Effects on the Mucus Fluid with Pulsatile Flow Influence of the Electromagnetic Field

The influence of pulsatile flow on the oscillatory motion of an incompressible conducting boundary layer mucus fluid flowing through porous media in a channel with elastic walls is inves-tigated. The oscillatory flow is treated as a cyclical time-dependent flux. The Laplace transform method using the Womersley number is used to solve non-linear equations controlling the motion through porous media under the influence of an electromagnetic field. The theoretical pulsatile flow of two liquid phase concurrent fluid streams, one kinematic and the other viscoelastic, is investi-gated in this study. To extend the model for various physiological fluids, we postulate that the vis-coelastic fluid has several distinct periods. We also apply our analytical findings to mucus and air-flow in the airways, identifying the wavelength that increases dynamic mucus permeability. The microorganism’s thickness, velocity, energy, molecular diffusion, skin friction, Nusselt number, Sherwood number, and Hartmann number are evaluated. Discussion is also supplied in various sections to investigate the mucosal flow process. © 2022 by the authors. Li-censee MDPI, Basel, Switzerland.

Mass transfer effects on mucus fluid in the presence of chemical reaction

The mucus fluid vehicle is impacted by the synthetic response that changes the physical science of liquid due to the thickness of the bodily fluid. Additionally, various issues in the respiratory system might happen because of bodily fluid adequacy. A central point of transportation of immunizations to forestall COVID-19 is the concentration level expected during movement, stockpiling, and dispersion. The current review stated that mucus fluid transportation is restrained through magnetic force originating due to heat variation. Permeable channel over respiratory disease and chemicals due to mass reaction–diffusion variation. The bodily fluid development is surveyed by the force, energy, and diffusion condition influence of body powers because of attractive field, source of heat cause of thermal conduction, resistance due to disease chemical reaction cause of concentration profile. The nonlinear arrangement of incomplete differential conditions is addressed by the Laplace transform technique, and MATLAB programming outcomes are initiated for momentum, temperature, and diffusion fields and inferred that the bodily fluid stream decelerates due to magnetic force. The skin friction, Nusselt number, Sherwood number, and the microorganism’s thickness are assessed and explained exhaustively. Furthermore, microorganisms are occupied in different elements to survey the mucus fluid mechanism.

Generalized Laplace-Type Transform Method for Solving Multilayer Diffusion Problems

Multilayer diffusion problems have found significant importance that they arise in many medical, environmental, and industrial applications of heat and mass transfer. In this article, we study the solvability of a one-dimensional nonhomogeneous multilayer diffusion problem. A new generalized Laplace-type integral transform is used, namely, the Mρ,m-transform. First, we reduce the nonhomogeneous multilayer diffusion problem into a sequence of one-layer diffusion problems including time-varying given functions, followed by solving a general nonhomogeneous one-layer diffusion problem via the Mρ,m-transform. Hence, by means of general interface conditions, a renewal equations’ system is determined. Finally, the Mρ,m-transform and its analytic inverse are used to obtain an explicit solution to the renewal equations’ system. Our results are of general attractiveness and comprise a number of previous works as special cases.

Generalized Mittag-Leffler Kernel Form Solutions of Free Convection Heat and Mass Transfer Flow of Maxwell Fluid with Newtonian Heating: Prabhakar Fractional Derivative Approach

In this article, the effects of Newtonian heating along with wall slip condition on temperature is critically examined on unsteady magnetohydrodynamic (MHD) flows of Prabhakar-like non integer Maxwell fluid near an infinitely vertical plate under constant concentration. For the sake of generalized memory effects, a new mathematical fractional model is formulated based on a newly introduced Prabhakar fractional operator with generalized Fourier’s law and Fick’s law. This fractional model has been solved analytically and exact solutions for dimensionless velocity, concentration, and energy equations are calculated in terms of Mittag-Leffler functions by employing the Laplace transformation method. Physical impacts of different parameters such as α, Pr, β, Sc, Gr, γ, and Gm are studied and demonstrated graphically by Mathcad software. Furthermore, to validate our current results, some limiting models such as classical Maxwell model, classical Newtonian model, and fractional Newtonian model are recovered from Prabhakar fractional Maxwell fluid. Moreover, we compare the results between Maxwell and Newtonian fluids for both fractional and classical cases with and without slip conditions, showing that the movement of the Maxwell fluid is faster than viscous fluid. Additionally, it is visualized that both classical Maxwell and viscous fluid have relatively higher velocity as compared to fractional Maxwell and viscous fluid.

Studies on the CO2 Capture by Coal Fly Ash Zeolites: Process Design and Simulation

At present, mitigating carbon emissions from energy production and industrial processes is more relevant than ever to limit climate change. The widespread implementation of carbon capture technologies requires the development of cost-effective and selective adsorbents with high CO2 capture capacity and low thermal recovery. Coal fly ash has been extensively studied as a raw material for the synthesis of low-cost zeolite-like adsorbents for CO2 capture. Laboratory tests for CO2 adsorption onto coal fly ash zeolites (CFAZ) reveal promising results, but detailed computational studies are required to clarify the applicability of these materials as CO2 adsorbents on a pilot and industrial scale. The present study provides results for the validation of a simulation model for the design of adsorption columns for CO2 capture on CFAZ based on the experimental equilibrium and dynamic adsorption on a laboratory scale. The simulations were performed using ProSim DAC dynamic adsorption software to study mass transfer and energy balance in the thermal swing adsorption mode and in the most widely operated adsorption unit configuration.

A Numerical Analysis of the Cooling Performance of a Hybrid Personal Cooling System (HPCS): Effects of Ambient Temperature and Relative Humidity.

Hybrid personal cooling systems (HPCS) incorporated with ventilation fans and phase change materials (PCMs) have shown its superior capability for mitigating workers' heat strain while performing heavy labor work in hot environments. In a previous study, the effects of thermal resistance of insulation pads, and latent heat and melting temperature of PCMs on the HPCS's thermal performance have been investigated. In addition to the aforementioned factors, environmental conditions, i.e., ambient temperature and relative humidity, also significantly affect the thermal performance of the HPCS. In this paper, a numerical parametric study was performed to investigate the effects of the environmental temperature and relative humidity (RH) on the thermal management of the HPCS. Five levels of air temperature under RH = 50% (i.e., 32, 34, 36, 38 and 40 °C) and four levels of environmental RH at two ambient temperatures of 36 and 40 °C were selected (i.e., RH = 30, 50, 70 and 90%) for the numerical analysis. Results show that high environmental temperatures could accelerate the PCM melting process and thereby weaken the cooling performance of HPCS. In the moderately hot environment (36 °C), HPCS presented good cooling performance with the maximum core temperature at around 37.5 °C during excise when the ambient RH ≤ 70%, whereas good cooling performance could be only seen under RH ≤ 50% in the extremely hot environment (40 °C). Thus, it may be concluded that the maximum environmental RH under which the HPCS exhibiting good cooling performance decreases with an increase in the environmental temperature.