Thermal Process Research Articles

Digital Twin Methodology in Food Processing: Basic Concepts and Applications.

The goal of this article is to present a concise review about digital twin (DT) methodology and its application in food processing. We aim to identify the building blocks, current state and bottlenecks, and to discuss future developments of this approach. DT methodology appears as a powerful approach for digital transformation of food production, via integration of modelling and simulation tools, sensors, actuators and communication platforms. This methodology allows developing virtual environments for real-time monitoring and controlling of processes, as well as providing actionable metrics for decision-making, which are not possible to obtain by physical sensors. So far, main applications were focused on refrigerated transport and storage of fresh produces, and thermal processes like cooking and drying. DT methodology can provide useful solutions to food industry towards productivity and sustainability, but requires of multidisciplinary efforts. Wide and effective implementation of this approach will largely depend on developing high-fidelity digital models with real-time simulation capability.

Magnetization mechanisms for non-destructive evaluation of low-carbon steels subject to early-stage low-temperature thermal oxidation

In this work, an investigation is done to identify the magnetic non-destructive testing techniques and their related magnetization mechanisms and, eventually, the associated indicators that present the most distinguishable response to changes in steel properties due to the onset and evolution of starting corrosion by thermal oxidation at low temperatures. This is found by measuring magnetic responses of Magnetic Hysteresis Cycle (MHC), Magnetic Barkhausen Noise (MBN), and Magnetic Incremental Permeability (MIP) at the early stage of corrosion. Herein, the magnetization mechanism identified by the Domain Wall Bulging (DWB) effect and represented by the indicator Δ|Z|MIP from the MIP response is ranked the most sensitive indicator by Pearson’s linear correlation coefficient (LCC). It is immediately followed by the Domain Wall’s Irreversible Motions (DWIM) represented by the MBN coercivity indicator. Both mechanisms are associated with the structure and kinetic of the magnetic domains, respectively, under low and medium magnetic excitations. The low-temperature thermal oxidation process set out the constructive effect of the oxide layer in the strain relief effect on the overall magnetic response of the corroded specimen. Discussions and conclusions are provided, as well as perspectives regarding the applicability of magnetic non-destructive testing techniques.

Standardized lab-scale production of the recombinant fusion protein HUG for the nanoscale analysis of bilirubin

The recombinant bifunctional protein HELP-UnaG (HUG) is a fusion product of the Human Elastin-like Polypeptide (HELP) with the bilirubin-binding fluorescent protein UnaG. HUG is used for the fluorometric detection of bilirubin in serum and a variety of biological fluids and extracts. Here we describe a detailed method for the standardized production and purification of HUG from E. coli extracts on a laboratory scale. This method takes advantage of the HELP-specific thermoreactive behavior that enables the separation of HUG from complex E. coli extracts by repeated precipitation/re-dissolution steps at near physiological temperature.•The method is based on the inverse thermal transition process.•The “green” method is affordable for basic laboratories and can be easily transferred to new users.

A molten salt energy storage integrated with combined heat and power system: scheme design and performance analysis

To investigate the flexibility and economic characteristics of a molten salt-combined heat and power (CHP) integrated system under different heat sources, this paper proposes a design scheme for a molten salt-CHP system based on flue gas heat storage, comparing it with main steam heat storage and reheated steam heat source schemes. First, a molten salt heat release sub-loop is designed, where the steam heated by the molten salt can either compensate for heating demands or enter the low-pressure turbine for work, meeting the flexible operation requirements of the unit. Secondly, in response to fluctuations in temperature and pressure parameters of the main steam and reheated steam in the flue gas heat storage scheme, a water-spray desuperheating device is arranged. Finally, a simulation experiment based on a 350 MW CHP was conducted, and the results show that the flue gas molten salt heat storage technology significantly reduces energy loss on the boiler side. Underrated load, compared to the main steam and reheated steam heat storage schemes, the flue gas heat storage scheme has the highest boiler exergy efficiency and total energy utilization efficiency, at 55.8% and 59.1% respectively. During the thermal storage process, the coal consumption index of the flue gas heat storage scheme decreases with increasing load, while conversely, during the heat release process, it increases with the load. The peak-shaving capacity increases with the load, reaching 78.4 MWh under the 75% THA condition. In the steam extraction heating scenario, coupling with the molten salt subsystem can expand the safe heating operation range of the original unit, increasing the maximum peak shaving range by 13.9%, and increasing the maximum heating capacity by 65.4%.

Camel milk whey powder formulated using thermal (spray-drying process) and non-thermal (ultrasonication) processing methods: Effect on physicochemical, technological, and functional properties

Whey protein concentrates (WPCs) are gaining importance as a functional ingredient due to their high technological and functional properties. In this study, Camel milk whey (CW) separated from skimmed camel milk, then either spray-dried (SD) at 170, 185 and 200 °C, or treated by ultrasonication (US) (20 kHz (for 5, 10 and 15 min followed by freeze-drying to obtain camel milk whey powder (CWP). The structural analysis of CWP was carried out by Fourier-Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) which showed no significant difference in the functional groups profile of US samples compared to control and SD samples. US samples showed some degree of crystallinity that was comparable to the control samples, while SD samples exhibited very low degree of crystallinity. The surface morphology, particle size, and surface charge of CWP were evaluated using scanning electron microscopy (SEM) and Zetasizer. The lowest particle size of 215.1 nm with surface charge of −21.6 mv was observed in SD-185 WPC. Moreover, SD samples revealed whiter color compared to the US-treated samples which were having lower L* values (P < 0.05). US-15 sample exhibited high protein solubility (100 %), whereas the SD-200 sample showed reduced solubility (92.7 %). Improvement in the emulsifying activity of CWP samples was observed after SD and US, with highest emulsifying activity index (EAI) values of 143.75 m2/g and 143.11 m2/g were reported for SD-185 and US-15 CWP samples, respectively. To conclude, SD and US were found to improve the physico-chemical, technological, and functional properties of CWP, and thus can be utilized as a promising strategy to preserve and enhance techno-functional properties of CWP

Research on the oxidation process of micro-boron below the melting point temperature

The ignition and combustion characteristics of boron and the energy release rate of boron-based fuel are closely related to the surface oxide layer of boron. To understand the oxidation process of boron below its melting point, the slow oxidation process of boron under different temperature and humidity storage conditions and the fast oxidation process under high-temperature conditions were investigated. The results indicate that the surface oxide layer mainly comprises boron (B), boron suboxides (BxOy), and boron trioxide (B2O3). When the degree of oxidation is low, BxOy and B are the main components. After deep oxidation, BxOy almost disappeared. The thickness and composition of the surface oxide layer vary with changes in environmental temperature, humidity, and aging time. The effect of temperature increase on the growth rate of the oxide layer thickness is significantly greater than that of moisture. With the prolongation of boron aging treatment time, the onset, end, and maximum weight gain rate temperatures of the boron thermal oxidation process all slightly decrease. As the ambient temperature increases, the formation of the oxide layer transitions from a unidirectional diffusion mechanism of oxygen into the interior of boron particles to a bidirectional diffusion mechanism of molten oxide and oxygen.

Investigation of the microstructural characteristics of laser-cladded Ti6Al4V titanium alloy and its corrosion behavior in simulated body fluid

Laser cladding technology has a wide range of potential industrial applications in the surface strengthening, repair and reuse of orthopedic implants. By employing this technique to conduct same-material surface restoration and enhancement on titanium alloys, it demonstrates significant developmental potential. However, the microstructure of laser additively manufactured titanium alloy differs significantly from that of traditional titanium alloys, which affects its corrosion resistance in human body fluids. To compare the corrosion resistance differences between the cladding layer and the substrate, this study investigates the microstructure of multi-pass laser cladding Ti6Al4V (TC4) titanium alloy and analyzes the corrosion morphology and corrosion products of the cladding layer in simulated body fluids (SBF). By comparing the electrochemical corrosion behavior of laser cladding with that of traditionally manufactured TC4, this research reveals the differences in corrosion resistance between the two titanium alloys. The research demonstrates that the microstructure of cladding primarily consists of prior-β grains and continuous grain boundary α phase, along with a complex basketweave structure composed of fine acicular α phase and lamellar α phase. Additionally, due to the complex thermal cycling process, the acicular α' colonies within the prior-β grains. These features enhance the cladding layer’s resistance to plastic deformation and increase microhardness, though with some uneven distribution. Interestingly, the TC4 cladding layer forms a porous passivation layer after corrosion, primarily composed of a TiO2 passivation film and deposits of hydroxyapatite and other phosphates. Due to the lower β-phase content, finer grains with higher energy states, and a greater proportion of high-angle grain boundaries (HAGBs) in the cladding layer, it exhibits higher electrochemical activity. As a result of these microstructural differences, the corrosion resistance of the TC4 cladding layer in SBF is inferior to that of TC4 manufactured using traditional techniques.

Advancing solar wastewater treatment: A photocatalytic process via green ZnO/g-C3N4 coatings and concentrated sunlight – Comprehensive insights into ciprofloxacin antibiotic inactivation

In this study, a sustainable method employing concentrated sunlight to achieve environmental remediation of wastewater, contaminated by Ciprofloxacin antibiotic (CIP), is thoroughly investigated. A green ZnO/g-C3N4 nanocomposite (NC) is used as a photocatalyst coating on glass to investigate the inactivation of CIP in water, in a flow-reactor configuration at small-prototype scale (10 liters/h, catalyst area 187.5 cm2). ZnO/g-C3N4 NC coatings were obtained by an in-situ thermal condensation process coupled with a green synthesis protocol and deposited on glass, via a simple drop casting method. Morphological and structural analyses of synthesized composites were performed with Fourier-Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX) and X-ray diffraction (XRD) techniques, while optical properties were studied with Diffuse Reflectance Spectroscopy (DRS). The degradation of CIP was first tested at a lab scale under simulated sunlight and then studied under sunlight in a parabolic trough concentrator (PTC). Suitable degradation of CIP (100%) was observed at 210 min via High-Performance Liquid Chromatography (HPLC) and the by-products were determined by Liquid Chromatography-Mass Spectroscopy (LC–MS). Microbiological tests revealed the absence of antibacterial activity in CIP water treated with ZnO/g-C3N4 NC photocatalyst against Staphylococcus aureus, Pseudomonas aeruginosa, and Priestia megaterium. Our results directly demonstrate the effective inactivation of CIP with a process designed for sustainability both in terms of energy input (solar) and scalability of materials. Also, the small-prototype scale of this investigation provides insights into the challenges arising from the perspective scale-up to an industrial application, aimed at antibiotics inactivation in wastewater and thus helping to prevent the spread of antimicrobial resistance (AMR).

Enhanced Remediation of Textile Dyes via Nonmetal-Modified Layered Graphitic Carbon Nitride: Influence of Various Oxygen Precursors

Layered two-dimensional (2D) graphitic carbon nitride (gCN)) doped with nonmetals has been extensively utilized as a photo-electrocatalyst. Herein, gCN doped with Oxygen was synthesized through a thermal polymerization process. The effect of various oxygen forerunners, namely citric acid (CA), oxalic acid (OX), and lactic acid (LA) on the photocatalytic ability of the gCN was analyzed. The proposed O-doped gCN samples basic characteristics were characterized by different analytical analyses. Indeed, the O-gCN has formed a sheet-like nature with a nanometre range, so often called a nanosheet. Superior photocatalytic performance was measured when the gCN was prepared by the CA as the O-precursor; 95% malachite green (MG) removal was attained within a short treatment time of 40min by adding a 20mg photocatalyst. The influences of different parameters of catalyst concentration, different precursors, and initial pH of MG degradation were also studied. The generation of active radicals played a major part in the degradation of the MG dye solution. These findings offer fundamental insight into utilizing the O-gCN for the remediation of textile effluents in water resources. The preparation of enormous metal-free catalysts via non-metal doping toward the environmental clean-up.

Study of substrate dependent Microstructural properties of sputtered Mo/CZTS heterojunctions using X Ray Diffraction

Thin films of CZTS (Cu2ZnSnS4) were deposited using radiofrequency sputtering (RF) at varying sputtering powers on soda lime glass coated with molybdenum (Mo). Direct current (DC) sputtering was used to deposit Mo thin films at various sputtering powers. Rapid thermal processing (RTP) was employed to anneal the thin films that had been deposited at temperatures of 300, 400, and 500°C. X ray diffraction (XRD) technique was used to probe thin films structurally. The microstructural characteristics, such as crystallite size and microstrain, were calculated. These properties, particularly crystallite size and microstrain, are critical in future applications as an absorber layer in a thin film solar cell. A comprehensive comparative study has been carried out using Scherrer method, Williamson-Hall method, Halder-Wagner method, Size-Strain plot method, and Wagner-Aqua method. Crystallite size and microstrain obtained in this work shows strong dependence on preferential orientation of DC sputtered Mo base layer. Crystallite size, microstrain measured shows similar trends. Microstrain obtained exhibits systematic relationship with variation in deposition parameters of DC sputtered Mo thin films and RF sputtered CZTS thin films. This dependency of CZTS microstructural features on base layer Mo growth conditions can be used in the future to apply CZTS as a solar cell absorber layer.

Assessing human exposure to organic contaminants in fish: A modeling approach integrating chemical bioconcentration and food thermal processing

Assessing human exposure to organic contaminants in fish: A modeling approach integrating chemical bioconcentration and food thermal processing

Improving gel properties of silver carp (Hypophthalmichthys molitrix) myosin with flavonols: Unveiling the advantages of isorhamnetin

This study explores the impact of flavonols (kaempferol, quercetin, kaempferitrin, and isorhamnetin) on the gel properties of myosin derived from silver carp (Hypophthalmichthys molitrix). Before employing a two-stage heating process, myosin samples are pretreated with flavonols, which enhance the structural stability of myosin and aid in the dispersion of myosin molecules. These pretreatments prepare the samples for subsequent thermal processing, where flavonols facilitate myosin unfolding and enhance intermolecular aggregation, thereby improving gel strength. This process also transforms free water within the gel to bound water, significantly increasing the water-holding capacity. Both macroscopic and microscopic rheological analyses suggest that flavonols, particularly isorhamnetin, notably enhance the elasticity and viscosity of myosin during the gelation process. Further, microstructural examinations employing techniques such as small-angle X-ray scattering and micro-computed tomography demonstrate that samples treated with flavonols develop denser and more uniform gel networks. Analytical studies reveal that flavonols, especially methylated derivatives like isorhamnetin, effectively promote gelation through strengthening hydrophobic interactions, disulfide bonds, and ionic interactions among myosin molecules. This research underscores the potential of flavonols as natural additives to enhance the quality and functional properties of surimi products, thereby elevating the processing standards of aquatic products.

Simulation and non-similar analysis of magnetized SWCNT-MWCNT hybrid nanofluid flow in porous media using Darcy-Forchheimer-Brinkman model

The field of hybrid nanofluid transport through porous media holds immense promise for optimizing thermal processing and various thermodynamic applications. This study investigates the flow dynamics of a hybrid nanofluid, comprising water and a synergistic combination of single-walled and multi-walled carbon nanotubes (SWCNT-MWCNT), as it traverses a vertically stretched porous surface. The mathematical modeling of this flow scenario considers the influential factors of magnetohydrodynamics (MHD), viscous dissipation, heat sources, and ohmic heating. The Darcy-Forchheimer-Brinkman model is employed to capture the transport of fluid through the porous medium. Through the application of Local Non-Similarity (LNS) technique, the governing equations are converted into a dimensionless system and solved numerically using the robust bvp4c function in MATLAB. Interestingly, higher values of heat source parameter leads to a rising trend in the temperature profile, highlighting the intricate interplay between the thermal and fluid dynamic aspects of the system. This work provides valuable insights into the tailored design of hybrid nanofluids and porous media configurations to harness their enhanced thermal transport capabilities, with potential applications in diverse fields such as energy storage systems, heat exchangers, and thermal management devices. The findings contribute to the broader understanding of hybrid nanofluid transport in porous media and pave the way for the development of innovative thermal management solutions in a wide range of industrial and technological domains.

Optimizing the Use of Flexible Retort Pouches for Production of Ready to Eat Cobia (Rachycentron canadum) Fish Chunks in Curry Medium

Cobia fish chunks in curry medium, a famous North Eastern Indian dish, was developed using Cobia (Rachycentron canadum) fish chunks prepared in a traditional culinary style. The present study was aimed to optimize F0 values for Cobia fish chunks in curry medium using flexible retortable pouches. The product underwent thermal processing at two distinct lethality levels and heat penetration rates, demonstrating equivalent cooling and heating lag effects. The fh values were 15 and 18.5 minutes for the product processed at F0 values of 9.29 and 8.42 minutes, respectively. The total process times were 39.79 and 38.80 minutes, respectively, for the F0 values of 8.42 and 9.29 minutes. Cook values for the processed product were 86.60 minutes for the F0 value of 8.42 minutes and 92.57 minutes for the F0 value of 9.29 minutes. Based on sensory characteristics, the product processed at an F0 value of 8.42 minutes was rated better over a storage period of 90 days.

A multi-faceted view of the X-ray spectral variability in Seyfert galaxy Ark 120

Abstract Utilizing a range of techniques including multi-band light curves, softness ratio analysis, structure functions, rms spectra, cross-correlation functions, and ratios of spectra from different intervals, we present a comprehensive study of the complex X-ray spectral variability in Seyfert 1 galaxy Ark 120, through re-analyzing its six XMM-Newton observations taken between 2003 and 2014. We find a clear ``softer-when-brighter" trend in the 2--10 keV power-law component over long timescales, with this trend being timescale dependent, as it is much weaker on shorter timescales, similar to that previously detected in NGC 4051. Notably, a rare ``harder-when-brighter" trend is observed during one exposure, indicating dynamic changes in the spectral variability behavior of the power-law component. This exceptional exposure, with the spectral variability indeed marked by a power-law pivoting at an unusually low energy of $\sim$ 2 keV, suggests intricate variations in the thermal Comptonization processes within the corona. Furthermore, when the data below 2 keV are included, we identify that the soft excess component adds significant complexity to the spectral variability, such as evidenced by a transition from ``harder-when-brighter” to ``softer-when-brighter” during another single exposure.Such extra complexity arises because the variability of the soft excess sometimes follows and sometimes does not follow the changes in the power-law component.Our findings underscore the necessity of applying multiple analytic techniques to fully capture the multifaceted spectral variability of AGNs.

An Analysis of Dynamic Recrystallization During the Reduction Pretreatment Process Using a Multiscale Model

In this study, a multiscale model is developed through secondary development (UMAT and UEXTERNALDB) in Abaqus with the objective of simulating the thermal deformation process with dynamic recrystallization behavior. The model couples the finite element method (FEM) with the multiphase field model (MPFM), thereby establishing bidirectional coupling between macroscopic mechanical behavior and microstructural evolution. A comparison between the single-element hot compression simulation and experimental results demonstrates that the model accurately simulates both the macroscopic mechanical behavior and microstructural evolution during the thermal deformation process, thereby exhibiting high precision. Simulations of the reduction pretreatment (RP) process under different reduction amounts and billet surface temperatures demonstrate that increasing the reduction amount and billet surface temperature significantly enhances both plastic deformation and the volume fraction of dynamic recrystallization in the billet core. This results in the closure of core voids and the refinement of the core microstructure, thereby providing valuable guidance for the development of optimal reduction pretreatment (RP) processes.

Thermal Oxidation Degradation Characteristics and Kinetic Analysis of Waste Shell Powders for Efficient Utilization and Environmental Protection

ABSTRACT The thermal oxidation degradation and kinetic behavior of four waste shell powders: Hyriopsis cumingii, abalone, scallop, and clam were investigated. The thermal oxidation degradation process was elucidated using thermogravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and the Coats-Redfern method. This process typically occurs in four stages, with the decomposition of CaCO₃ (Stage III) being pivotal. Notably, clam and scallop powders exhibited the highest CaO yields of approximately 55.1% and 55.0%, respectively. Although abalone powder had a lower yield of 50.2%, it demonstrated the lowest activation energy of 118.08 kJ/mol in Stage III, suggesting potential energy and cost savings during CaO conversion. High-temperature calcination altered the chemical composition and microstructure of the shell powders, resulting in rough and porous CaO surfaces conducive to heavy metal ion and pollutant adsorption. The research provides a theoretical framework and experimental validation for the sustainable utilization of calcined shell powders, fostering efficient shell resource management and environmental protection.

Activated Phenyl Ester Vitrimers.

Aromatic esters are amongst the oldest known chemical motifs that allow for thermal (re)processing of thermosetting polymers. Moreover, phenyl esters are generally known as activated esters that do not require a catalyst to undergo acyl transfer reactions. Even though dynamic aromatic esters find applications in commercialized thermoset formulations, all-aromatic esters have found limited use so far in the design of covalent adaptable networks (CAN) as a result of their high glass transition temperature (Tg)and specific curing process. Here, a strategy to include partly aromatic esters as dynamic cross-links inside low Tg (-40°C) thermosetting formulations, using aliphatic esters derived from para-hydroxybenzoic acid, which serves as a highly activated phenol or as a reactive "phenylogous anhydride" is reported. A small molecule study shows that the activated phenyl ester bonds can readily exchange with free phenol moieties at 200°C under catalyst-free conditions, while the addition of a catalyst allows for a faster exchange. Robust and hydrophobic polymer networks are conveniently prepared via rapid thiol-ene UV-curing of unsaturated phenol esters. The obtained networks show high thermal stability (350°C), fast processability, good water resistance, and low creep up to 120°C, thus showing good promise as a platform for CAN.

Water desalination using atmospheric pressure plasma combined with thermal treatment

AbstractHerein, a novel method is presented for enhancing the thermal desalination process of saline water and seawater using atmospheric pressure plasma (APP). The effect of APP treatment combined with thermal heating (APP-TH) on the energy consumption, conductivity, and pH of seawater and saline water is investigated. Utilizing scanning electron microscopy and X-ray diffractometry, the evolution of the morphology, structure, and chemical composition of precipitated crystals is characterized. The APP-TH method reduces the energy consumption for desalination by 40.5% for saline water and by 52.82% for seawater when compared to the TH-only method. The pH value remains approximately unchanged, decreasing slightly for the saline water from 7.1 for untreated saline water to 7.05 after APP-TH treatment. However, after APP-TH treatment, the pH value of the seawater increased slightly, from 7 to 7.8. The total dissolved salts decreased after APP-TH treatment, lowering the conductivity of the saline water from 65,000 µS/cm to 160 µS/cm and the conductivity of the seawater from 58,200 µS/cm to 243 µS/cm. Moreover, the size of precipitated crystals from saline water is 31.47 nm after APP-TH treatment, compared to 55.59 nm after TH-only treatment. They also dropped from 41 nm to 39.5 nm for seawater. Compared with traditional approaches, this research proposes an optimistic solution to address global potable water scarcity issues.

Innovative Strategies for Thermal Energy Optimization and Renewable Energy Integration in Net-Zero-Energy Buildings: A Comprehensive Review

The thermal performance and energy efficiency of buildings are critical factors in achieving sustainable energy systems as energy needs for heating and cooling are expected to represent more than 50% of global final energy consumption. This study analyzes conventional renewable energy systems for heating and cooling in buildings, focusing on strategies for developing net-zero-energy buildings. This review covers the integration of renewable energy, the use of intelligent energy management systems, and the optimization of thermal processes. It also compares various systems based on their advantages and limitations and analyzes emerging trends in the thermal management of buildings in different climate zones. The synthesis of recent literature highlights practical recommendations for achieving high thermal performance in buildings, including the importance of selecting appropriate energy systems based on local climatic conditions, optimizing system efficiency, and taking advantage of new materials and advanced technologies. This review aims to contribute to promoting sustainable construction practices with the integration of renewable energy sources and improving the energy efficiency of buildings.