Simultaneous Mass Research Articles

Numerical Investigation of Influence of Extent and Position of a Bypass on the Performance of a Single Unit Liquid Desiccant Based Evaporative Cooler

Air-conditioning of buildings is more energy-consuming with widely used vapour compression refrigeration systems in hot and humid areas. Alternatively, evaporative cooling does not show much effect in sultry regions because of increased humidity despite the minimum energy consumption. Indirect evaporative cooling is a promising alternative to direct evaporative cooling systems, but it suffers from low cooling effectiveness and is unsuitable for highly humid regions. Considering the above facts an alternative liquid desiccant-assisted modified M-cycle cooling system is proposed and examined numerically in the present work. The proposed cooling and dehumidification system is a simple unit incorporating chemical dehumidification and regenerative evaporative cooling in a single unit. A simultaneous heat and mass transfer model is developed for the numerical analysis. The numerical code is written in MATLAB and is validated with results available in the literature. Further, numerical analysis was carried out for the effect of various parameters on the performance of the proposed cooling system. The study shows an improvement of 19.2% in dew point effectiveness by incorporating an intermediate opening in the plate separating the product air and working air channels.

Ensuring the safety of citizens by rescuers/police officers in case of a chemical attack (accident at a chemical enterprise) in the conditions of marital law

The work deals with the urgent problem of ensuring the safety of life of the population in the conditions of martial law, introduced in Ukraine – providing premedical assistance to victims of a chemical attack (as a result of the action of dangerous factors of a man-made accident at a specialized chemical enterprise).
 The potential possibilities of means of defeating the units of the chemical forces of the aggressor state are analyzed, the cases of the use of chemical weapons by the occupiers in relation to both the units of the Armed Forces of Ukraine and the civilian population during the war in Ukraine, as well as the real situations of destroyed chemical plants in many regions of the country, are described and summarized.
 On the basis of the analysis of operational publications in the Internet and scientific works of a great number of scientists, the general algorithm of rescue actions during the evacuation of victims of a chemical attack/accident (workers/residents) was considered, modern approaches in the order of providing premedical aid both at chemical enterprises and at home conditions when people are injured by the most common chemical substances were clarified, recommendations concerning compliance by police officers with established rules of conduct at the scene of the incident are offered.
 The main signs that characterize the beginning of a chemical attack in the conditions of martial law and allow the population to identify it quickly are given: 1) chemical alarm signals; 2) features of air raids or enemy artillery fire; 3) simultaneous mass death of small animals, birds and insects.
 The peculiarities of the effect on the human body of such substances as chlorine, ammonia, hydrogen chloride (hydrochloric acid), nitrogen (nitrogen N), nitric acid, oxide (dioxin) of nitrogen, for each of which characteristic symptoms of damage for the victim are determined, the procedure for providing premedical aid to victims in case of damage by them, as well as under the influence of chemical weapons (sarin, phosgene) has been specified.
 Based on the analysis of special literature and the results of the conducted research, a generalization was made regarding the importance of training the population in effective (and therefore safe) actions in the event of a chemical attack by the military units of the aggressor state (a man-made accident at chemical enterprises), the need to observe the established rules of conduct and safety measures in the case of a missile/artillery attack by the occupiers, regardless of the region or territory of fighting actions in Ukraine

Advanced motion tracking for interactive mass spectrometry imaging (IMSI)

Mass spectrometry imaging (MSI) is a powerful analytical technique for the two-dimensional (2D) localization of chemicals on surfaces. Conventional MSI experiments require to predefine the surface of interest based on photographic or microscopic images. Typically, these boundaries can no longer be changed or adjusted once the experiment has been started. In terms of a more interactive approach we recently developed a pen-like ionization interface which is directly connected to the mass spectrometer. The device allows the user to ionize chemicals by desorption electrospray ionization (DESI) and to freely move the interface over a surface of interest. A mini camera, which is mounted on the tip of the pen, magnifies the desorption area and enables a simple positioning of the pen. The combination of optical data from the camera module and chemical data obtained by mass analysis facilitates a novel type of imaging experiment: interactive mass spectrometry imaging (IMSI). For this application, we present a novel approach for a robust, optical flow-based motion detection. While the live video stream from the camera is used to track the pen's motion across the surface a post-acquisition algorithm correlates the coordinates of the pen trajectory with respective mass spectra obtained from a simultaneous mass spectrometric data acquisition. This algorithm is no longer dependent on a single, manually applied optical marker on the sample surface, which has to be visible on all video frames throughout the analysis. The advanced DESI-IMSI method was successfully tested on inkjet-printed letters as well as mouse brain tissue samples. Validation of the results was done by comparing DESI-IMSI with standard DESI-MSI data.

Sensitivity analysis of a system with two closely spaced modes using structural dynamic modification

The first-order sensitivity equations based upon a Taylor expansion are not accurate in systems with closely space modes. Moreover, a good correlation can exist in terms of mass and stiffness between two models with closely spaced modes, but low values of modal assurance criteria (MAC) can be obtained because mode shapes rotate in the subspace spanned by the closely spaced mode shapes. In this work, the sensitivity of the eigenvalues and eigenvectors of a system with two closely spaced modes is studied, solving analytically the corresponding un-damped eigenvalue problem derived from the structural dynamic modification theory. Three different perturbation cases have been considered: stiffness change ΔK, mass change ΔM, and simultaneous mass and stiffness changes. The accuracy of the equations presented in this paper has been validated by simulations in a 4 DOF system with the first two modes closely spaced. The predictions provided by the analytical equations (local eigenvalue problem) are compared with the results obtained solving the full eigenvalue problem.

Holographic imaging platform for particle discrimination based on simultaneous mass density and refractive index measurements.

Real-time detection, classification and identification of aerosol particles is crucial in various industries and public health areas. In order to circumvent the limitations of existing particle analysis methods for efficient discrimination, we demonstrate a compact digital in-line holographic microscopy platform with an inertial spectrometer for simultaneous measurement of two independent fingerprint parameters at single species level. In particular, by interrogating the particle location and size captured with the platform, particle mass density can be estimated. Furthermore, by employing Monte Carlo fitting to the Lorenz-Mie theory, the refractive index of each particle can also be extracted from the interference patterns. It is demonstrated that the combination of mass density and optical density characterization unambiguously enhances the discriminatory power of the system, especially when dealing with particles that exhibit similar mass densities but distinctive refractive indices or vice versa. This innovative approach represents a significant advancement in particle characterization and composition identification, with potential applications in various industrial, scientific, and research domains. An iOS-based app interface is then customized for wireless controlling of the CMOS imager, image acquisition, reconstruction, and data analysis. The imaging platform proposed in this work has prominent advantages including compactness, accuracy, efficiency, high throughput, and remote sensing capability, which is especially relevant for applications where on-site/remote metrology and identification of particles is required.

Modelling post-frying oil absorption, water loss, and cooling of potato cylinders

A simultaneous heat and mass transfer model based on global coefficients was proposed to describe the oil absorption, water loss, and temperature changes occurring during the post-frying period of potato cylinders. The model was solved in Matlab® and simultaneously fitted to post-frying kinetics from literature, describing the surface and penetrated surface oil contents, as well as the surface and centre temperatures of potato cylinders at six holding temperatures (25, 100, 120, 140, 160, and 180°C). Besides, simple algorithms were developed to evaluate the oil layer thickness and the minimum oil penetration distance, obtained by assuming the potato cylinder was split into a dry zone, where the oil was absorbed, and a moist zone free from oil. The model achieved a good reproduction of fitted responses with average deviations ranging from 1.9 to 11.7% for all post-frying holding temperatures. Estimated distribution coefficients evidenced higher oil absorption at low holding temperatures, increasing from 0.66 kg surface oil/kg absorbed oil at 25°C to 2.60 kg surface oil/kg absorbed oil at 180°C, while no temperature influence on mass transfer coefficient was found under the explored experimental conditions (p > 0.05). The estimated minimum oil penetration distance (thickness of the dry zone region) after the post-frying stage (229 to 506 µm) showed a good agreement with crust thickness values from literature.

Experimental investigation on the thermal and flow performance of a thermodynamically-balanced packed bed humidification system

In this paper, a packed bed humidification system filled with corrugated wire mesh was experimentally investigated to obtain a better humidification performance. To thermodynamically balance the simultaneous heat and mass transfer process, multiple water injection bypasses were fabricated at different packing heights based on the entropy generation minimization method. In addition to the inlet water temperature, the influences of the liquid–gas ratio and injection ratio on the humidification capacity, energy effectiveness, and pressure drop were respectively studied and discussed. The experimental and comparison results demonstrated that the established humidification device was robust and superior. It was summarized that raising the number of injections can significantly elevate the humidification capacity, and synchronously magnify the pressure drop for all the cases, while the effectiveness behaved a reverse trend. Additionally, a higher value of the inlet water temperature could increase the humidification capacity and effectiveness, as well as the pressure drop. And, an elevation amplitude of the humidification capacity emerged as 35.51% for the double water injections with a maximum value of 1.48 × 10−2 kgs−1 once the liquid–gas ratio increased from 1 to 1.36, while the value was 39.13% as the injection ratio raised from 0.33 to 0.7. Furthermore, it was illustrated that increasing the mass flow rate of the liquid will reduce the effectiveness when the heat capacity rate ratio is larger than 1, and the effectiveness can reach 0.97 at Twi = 70 °C. In the process of thermodynamic balancing, the increase in the pressure drop of humid air should receive more attention for the designer and researcher related to the packed bed humidifier.

Role of nanolayer on the dynamics of tri-hybrid nanofluid subject to gyrotactic microorganisms and nanoparticles morphology vis two porous disks

This paper investigates the simultaneous heat and mass transfer phenomena in nanolayers induced by morphology, motile microorganisms, and magnetohydrodynamics (MHD). The study also discusses the crucial role of viscous dissipation resulting from joule heating effects in the flow of ternary hybrid nanofluids, considering both model thermal conductivity and nanolayer thermal conductivity. The influence of various types of nanoparticles on thermal conductivity (TC) and nanolayer thermal conductivity (NTC) is examined, with a focus on the significance of chemical reactions and concentration equations. To solve the nonlinear system of ordinary differential equations, a stable and accurate numerical method is employed. The study provides valuable engineering insights, summarizing key parameters such as skin friction coefficient, Nusselt number, Sherwood number, and motile number. Several nondimensional parameter effects like Re, Pr, β, Pe,α,h,r,γ, and Sc are shown in graphical and tabulation form for both porous disks. The addition of nanolayer thermal conductivity of ternary nanoparticles at a level of 5% enhances the heat transfer rate. When the values of the radius of nanoparticles and nanolayer thickness increase, the flow of tri-hybrid nanofluid's nanolayer thermal conductivity behaves oppositely.

SAT569 Papillary Thyroid Carcinoma With Renal Metastasis Treated With Radioactive Iodine: A Case Report

Abstract Disclosure: A.A. Apa-ap: None. M.B. Sedurante: None. J. Lacuata: None. J. Gacula: None. V. Lee: None. M.L. Hernandez: None. INTRODUCTION. Papillary thyroid cancer (PTC) is one of the most treatable cancers in comparison to undifferentiated thyroid malignancies. It advances slowly, and there is only 1-4 percent of cases of distant metastases. Renal involvement from PTC is very rare with an incidence of 0.47 percent. CASE DESCRIPTION. This paper describes a 34-year-old Filipino female presenting with an 8-year history of hoarseness and a gradually enlarging anterior neck mass. Metastatic workup revealed innumerable bilateral pulmonary nodules bilateral cervical lymphadenopathy, and bilateral renal mass on CT scan. The right pole of the kidney shows a solid heterogeneously enhancing partially-exophytic focus measuring 4.9 x 4.2 x 4.3cm likely a primary renal cell carcinoma versus metastasis. The left renal mass shows a hypodense non-enhancing partially-exophytic focus measuring 3.9 x 3.6 x 3.6cm probably a renal cyst. Clinically, the patient did not show any urinary symptoms and creatine clearance was normal. The patient underwent total thyroidectomy and neck dissection and histopathology revealed PTC. The patient underwent simultaneous ultrasound right renal mass biopsy which revealed few fragments of thyroid tissues with atypia most likely representative of metastasis of PTC. Since the radiographic finding was suggestive of a renal cyst, the left renal mass was not biopsied. Patient refused nephrectomy and underwent 1 cycle of Radioactive Iodine (RAI) Therapy. Post therapy whole body scan showed mildly increased and diffuse tracer uptake activity in bilateral lungs and large avid focus, approximately 5.0 x 4.4 cm, seen in the inferior pole of the right kidney. Surveillance showed increased thyroglobulin. To date, the patient still refused surgery and is contemplating undergoing another cycle of RAI therapy. DISCUSSION. Due to the rarity of the metastatic site, the ideal course of treatment for this illness is unknown. To our knowledge, there are only approximate of 30 case reports on WDTC with renal metastasis in the literature. Presentation: Saturday, June 17, 2023

Volcanism-driven lacustrine redox fluctuations were responsible for the formation of the Jehol Lagerstätte: Evidence from a high-resolution Aptian sedimentary core, Northeast China

While a “volcanic Pompeii” model is well accepted as the cause of mass mortality and exceptional preservation of the Jehol Biota, no consensus has been reached thus far regarding the cause of mass mortality of fossils found in interbedded finely laminated sediments. We propose that volcanically driven, lacustrine redox fluctuations were responsible for the formation of the Jehol Lagerstätte, based on data obtained from a new drill core of Lower Cretaceous sedimentary rocks in the Chaoyang Basin, Northeast China. We found manganese-rich carbonates are interbedded with molybdenum-rich black mudstones and tuffs, and phosphatized fossils in the drill core. The elemental enrichment factors for molybdenum are much higher than for uranium in the black mudstones, suggesting the role of the manganese particulate-shuttle in deposition of this element. The manganese-rich carbonates are formed by the reaction of manganese oxides with organic matter, indicating an oxidized water column. This process accelerates the enrichment of molybdenum under anoxic non-sulfidic conditions. The interbedded manganese carbonates and molybdenum-rich mudstones thus record redox fluctuations in the lacustrine depositional environment. Given the numerous tephra in the black mudstones and soft-sediment deformation structures ostensibly associated with seismicity, we propose that the redox fluctuations were caused by lake eutrophication and turnover driven by volcanism that was ultimately related to the destruction of the North China Craton. These volcanically induced redox fluctuations, along with the toxicity of the volcanic gases, may have caused the simultaneous mass mortality of aquatic, terrestrial, and avian fauna. Micro-X-ray fluorescence, energy dispersive X-ray spectroscopy, and Raman mapping show that the preservation of fossils was mainly due to phosphatization. Fluctuating redox conditions facilitated phosphate enrichment in sediments. Both the oxic and anoxic non-sulfidic conditions were conducive to the preservation of organisms by phosphatization, and oxidation was favorable for phosphate mineralization, both contributing to the exceptional preservation of the Jehol Biota fossils.

Microrotating chemically reactive hybrid nanomaterial in a high porous medium influenced by Cattaneo-Christov double diffusion and non-linear slip

ABSTRACT A simultaneous heat and mass transfer due to microrotating Darcy-Forchheimer flow of hybrid nanofluid over a moving thin needle is investigated. Darcy-Forchheimer medium accommodating hybrid nanofluid flow yields greater heat transfer rate, thereby leading to greater mass transfer rate over thin needle in industrial applications such as blood flow problems, aerodynamics, transportation, coating of wires, lubrication, and geothermal power generation. The thermophoresis and Brownian motion phenomena are introduced to enrich thermal treatment. Heat and mass transfer are accompanied by Cattaneo-Christov heat and mass flux. The hybrid nanofluid is radiative and dissipative in nature. Arrhenius pre-exponential factor law is introduced. Entropy generation analysis is carried out. The 4th order Runge-Kutta method along with shooting technique is devised to get requisite numerical solution of the transformed non-dimensional system of equations. Darcy-Forchheimer effect to simultaneous heat and mass transfer of microrotating hybrid nanofluid flow over thin needle subject to non-linear slip is the novelty of present study which is beyond of previous investigations. Rise in Forchheimer number (strengthening Darcy Forchheimer medium) leads to surface viscous drag decreases by 11.11% for hybrid nanofluid and 10.78% for pure nanofluid indicating the control of momentum transfer, thereby regulating heat transfer rate effectively.

Exploring the simultaneous mass transport of nimesulide and paracetamol adsorption on activated carbon: A PVSDM approach

Pore Volume and Surface Diffusion Model (PVSDM) was advanced to Extended PVSDM for modeling multicomponent adsorption systems. The dynamic adsorption of nimesulide and paracetamol on activated carbon was investigated through single and binary adsorption experiments. Langmuir and Extended Langmuir isotherms were used as local equilibrium functions, respectively. The results reveal that single and binary adsorption were affected by both external mass transport and intraparticle diffusion. The coexistence of nimesulide and paracetamol led to a competitive adsorption phenomenon, wherein nimesulide exhibited a higher affinity for the activated carbon surface, primarily occupying its surface active sites, while paracetamol diffuse into the pore volume to be adsorbed, especially at higher initial pharmaceutical concentrations. These findings emphasize the necessity of employing the robust Extended PVSDM for predicting the complex dynamics of binary adsorption. The findings also provide valuable insights that can significantly contribute to the development of efficient adsorption processes, addressing urgent environmental challenges.

Fluidized bed drying of supported Catalysts: Effect of process parameters

Fluidized bed drying is an important unit operation in the manufacturing of supported catalysts. This unit operation remains a challenging step due to simultaneous heat and mass transfer, making it difficult to predict and scale up. This work focuses on applying a mathematical model to predict drying curves and drying rates in a fluidized bed dryer. The model was compared to experiments in a Glatt GPCG-1 fluidized bed dryer. Experiments were conducted by varying air flow rate, bed loading, inlet air temperature, and initial moisture content using water impregnated supports. Results from the model showed good agreement with experimentaldrying curves. The model predicted the drying time for cases that were not initially fluidized. The modelpredicts drying curves for changes in single process parameters when the experiments started in the same drying period. Lastly, the model prediction was extended to multiple changes in process parameters and showed good agreement.

Deriving physical parameters of unresolved star clusters

Context. This work is the seventh study in a series dedicated to investigating degeneracies of simultaneous age, mass, extinction, and metallicity determinations of partially resolved or unresolved star clusters with Hubble Space Telescope broadband aperture photometry. In the sixth work (hereafter, Paper I), it was demonstrated that the adaptive aperture photometry, performed to avoid the majority of the projected foreground and background stars falling within the apertures, gives more consistent colour indices for star clusters. Aims. In this study, we aim to supplement the homogeneous multi-colour aperture photometry results published in Paper I and provide a complete M 31 Panchromatic Hubble Andromeda Treasury (PHAT) survey star cluster photometry catalogue for further analysis. Methods. Following Paper I, we used a two-aperture approach for photometry. The first aperture is the standard one used to measure total cluster fluxes. The second (smaller) aperture is introduced to avoid the bright foreground and background stars projecting onto the clusters. We selected the radii of smaller apertures to be larger than the half-light radii of the clusters. Results. We present the second part of the star cluster aperture photometry catalogues for a sample of 1477 star clusters from the M 31 PHAT survey not covered in Paper I. Compared to the M 31 PHAT star cluster aperture photometry catalogue published by Johnson et al., adjustments were made to the cluster centre coordinates, aperture sizes, and sky background levels.

Process parameters optimization in machining of monel 400 alloy using abrasive water jet machining

This research examines the optimum machining features for abrasive water jet cutting of Monel 400 alloy. This alloy system faces significant challenges in conventional machining and can be surpassed by using the coolest machining technology, such as AWJM. In this experimental investigation, the water beam jet pressure (AP), the nozzle jet traverse speed (NS), and the abrasive flow rate (AMF) were used to explore the kerf taper angle (Kta) and surface roughness (Ra) response variables. The experimental L-9 layout (Taguchi's/L-9(−|-) standard orthogonal array) was used to run the experiment. The S/N ratios for each experimental run were determined using a mono-output response optimization technique. The input characteristics, such as water beam jet pressure (AP) and abrasive flow rate (AMF), were determined to have the most substantial effects on kerf taper angle (Kta) and surface roughness (Ra). While increased water pressure (AP) caused a narrowed jet, reducing the kerf taper angle (Kta) and surface roughness (Ra). Its simultaneous abrasive mass flow rate (AMF) increase causes constant erosion on the cutting front, resulting in a smooth surface roughness (Ra) and less kerf taper angle (Kta). Confirmation tests were carried out using the optimal input parameter combinations found by the statistical program to establish effective solutions to the machining.

Design of multi-layered gradient catalysts for efficient proton exchange membrane fuel cells

Efficient catalyst layers (CLs) in proton exchange membrane fuel cells (PEMFCs) should possess a highly active surface for electrochemical reaction and an ideal platform for simultaneous mass transfer. Efforts have been devoted to lower the widely used Pt and Nafion loading due to their high cost. However, the increase in gas transport resistance and decrease in transfer ability of protons and electrons result in a degraded fuel cell performance. Therefore, CL design with optimal efficiency is important for high performance and stability of PEMFCs. In this study, we design gradient multi-layered CLs in which the loadings of Pt–C catalyst and Nafion ionomer are set differently for each layer to increase efficiency. For ideal cell performance, the ionomer loading should be higher near the membrane layer and Pt–C loading should be higher near the gas diffusion layer. In addition, we confirm that if the loading difference between layers in the gradient CL becomes excessively large, performance can degrade due to the non-uniform Pt active surface. Thus, we compared 1-layer, 3-layer and 5-layer CLs, and designing more layers to reduce the difference in loading between layers results in higher electrochemical surface area (ECSA) and improved performance.

(Invited) Understanding Oxygen Transport in Polymer Electrolyte Membrane Water Electrolyzers Using X-Ray Computed Tomography

This study aims to understand the fundamental processes that affect catalyst utilization and gas transport through the porous media in polymer electrolyte water electrolyzers (PEWEs) to optimize porous transport layers (PTLs) and flow-fields. We designed a novel operando x-ray computed tomography (CT) cell that can resolve oxygen transport along a 10 cm x 1 cm membrane electrode assembly (MEA) active area. The flow field with two straight channels was designed for this operando cell. X-ray CT with the field of view (FOV) of about 3 mm x 2 mm and resolution of 0.7 um allowed visualizing MEA and flow channels of operando PEWEs. The cell features three observation windows that are transparent to x-rays. These are located near the inlet, in the middle of the flow-channels and at the outlet. In addition, thermocouples are embedded in various locations in the cell to measure temperature profiles of the cell. Oxygen content in the flow-channels was observed for various current densities using 2D radiography technique, with 5 ms time resolution step size. The cell morphology and steady-state oxygen distribution in the PTL were observed using stained water (stained with NaI). The results show significant oxygen enrichment in the channels near the outlet, as well as higher oxygen presence in the PTLs near the outlet. This new cell design can enable simultaneous heat and mass transport measurements along the flow channels. Inlet-outlet variations in oxygen content at scale of 10 cm is of relevant to single cell testing in the laboratory.

A regression-based approach for the explicit modeling of simultaneous heat and mass transfer of air-to-refrigerant microchannel heat exchangers

With the increasing utilization of mathematical models for heat exchanger optimization studies, there lies the demand for robust and accurate yet fast modeling methodologies on the simultaneous heat and mass transfer process. This research conducted an in-depth review of mathematical models for heat exchanger performance prediction. We categorized typical modeling methodologies into lumped models, zone models, and numerical methods. The review of mathematical models revealed the iterative approaches for performance prediction of fully wet conditions are computationally expensive. Also, the assumptions and derivations based on adiabatic fin tips do not allow flexibility with advanced fin designs. In order to address these two issues, this research developed a systematic regression approach under a common range of geometrical and thermal parameters under both wet and dry conditions, single-phase and two-phase refrigerant flow. Such regression analysis provides an explicit calculation procedure for micro-channel heat exchangers' performance prediction. The improved semi-regression models show advances in accuracy and calculation speed within the selected ranges of geometries and working conditions for heat pump applications.

IN SITU ENCAPSULATION OF NICKEL NANOPARTICLES IN POLYSACCHARIDE SHELLS DURING THEIR FABRICATION BY ELECTRICAL EXPLOSION OF WIRE

Nickel nanoparticles are obtained by electrical explosion of wire under the action of a high-voltage discharge followed by condensation in an inert gas medium. When butane is added to the gas medium, a carbon shell is deposited onto the condensing nickel particles. Immediately after the synthesis, liquid-phase modification of nanoparticles is carried out with aqueous solutions of polysaccharides agarose and gellan. As a result, a polymer shell is formed on particles of Ni and nickel particles coated with a carbon shell (Ni@C). The dispersity, crystalline structure, and magnetic properties of Ni and Ni@C nanoparticles are characterized by transmission microscopy, X-ray diffraction analysis, and vibration magnetometry. The total carboncontent on the surface of the nanoparticles is determined by thermal analysis with simultaneous mass spectrometry. It is shown that, under the studied conditions, polysaccharides are deposited onto the nanoparticles in amounts up to 2 wt % to form a shell with a thickness of about 4 nm. When agarose is used as a modifier, the content of the polysaccharide increases with the concentration of the modifying solution. When gellan is used as a modifier, a more complex concentration dependence is observed: an initial increase is followed by a decrease in the amount of deposited polysaccharide. The results are discussed from the viewpoint of the influence of the molecular weight of a polymer on the adsorption process.

Pore Evolution in Cell Walls of Food Tissue during Microwave-Assisted Drying: An In-Depth Investigation.

Microwave (MW) heating is a unique approach that, unlike conduction- and convection-based heating, can provide volumetric heating. Complex microstructural changes in food materials occur because of simultaneous heat and mass transfer during drying, significantly affecting food structure and quality. Food properties, drying methods, and other drying parameters all have an impact on the microstructure of food samples, which in turn affects drying kinetics and food quality. However, no study has been undertaken to investigate the development of nano-micro-pores (NM-pores) on the cell walls and their relationship with the moisture migration mechanism. This study presents a novel investigation of the microstructural changes in food during microwave drying, with a focus on the formation of nano-micro-pores (NM-pores) on cell walls and their impact on moisture transport kinetics. The utilized hot air was maintained at a temperature of 70 °C, whereas microwave (MW) power levels of 100 W, 200 W, 300 W, and 400 W were used in microwave drying. The findings of the study indicate that the development of NM-pores occurs only during intermittent microwave drying (IMCD), while the cell wall of the food samples tends to burn or collapse in continuous microwave drying (CMD) due to the high heat generated. Additionally, no NM-pores were observed in the cell wall during convective drying. During IMCD with microwave power ranging from 100 W to 400 W, a range of pore sizes from 0.1 μm to 8.5 μm were observed. Due to the formation of NM-pores and collapses, MW drying takes around 10-20 times less time than convective drying to remove the same quantity of moisture. The effective moisture diffusivity values were found to be the highest in CMD at 4.70 × 10-07 m2/s and the lowest in CD at 2.43 × 10-09 m2/s. IMCD showed a moderate diffusivity of 2.45 × 10-08 m2/s. This study investigates the formation of NM-pores on cell walls during microwave drying and their impact on moisture transport kinetics and establishes correlations between microstructure modifications and moisture migration pathways.