Search Results (136)

The advancement of non-thermal disinfection technologies represents a critical pathway for ensuring food safety, meeting environmental sustainability requirements, and meeting consumer preferences for clean-label products. This study systematically evaluated the combined preservation effect of ultrasonic-assisted slightly acidic electrolyzed water (US+SAEW) on mirror carp fillets during refrigeration. Results demonstrated that US+SAEW exhibited superior antimicrobial efficacy compared to individual US or SAEW, achieving reductions of 0.73, 0.74, and 0.79 log CFU/g in total viable counts (TVC), Aeromonas bacteria, and lactic acid bacteria counts compared to the control, respectively. Furthermore, the combined intervention significantly suppressed microbial proliferation throughout the refrigeration period while simultaneously delaying protein and lipid degradation/oxidation induced by spoilage bacteria, thereby inhibiting the formation of alkaline nitrogenous compounds. Consequently, lower levels of pH, total volatile basic nitrogen (TVB-N), protein carbonyl, and thiobarbituric acid reactive substances (TBARS) were observed in US+SAEW compared to the other treatments. Multimodal characterization through low-field nuclear magnetic resonance (LF-NMR), texture, and color analysis confirmed that US+SAEW effectively preserved quality characteristics, extending the shelf life of mirror carp fillets by four days. This study provides a novel non-thermal preservation strategy that combines microbial safety maintenance with quality retention, offering particular advantages for thermolabile food. Full article

This study systematically investigates the impact of Cu²⁺ doping on the structural, magnetic, and magnetocaloric properties of Cu_xCo_1−xCr₂O₄ nanoparticles synthesized via a solution combustion method. Cu incorporation up to x = 20% induces a progressive structural transformation from a cubic spinel to a trigonal corundum phase, as confirmed by X-ray diffraction and Raman spectroscopy. The doping process also leads to increased particle size, improved crystallinity, and reduced agglomeration. Magnetic measurements reveal a transition from hard to soft ferrimagnetic behavior with increasing Cu content, accompanied by a notable rise in the Curie temperature from 97.7 K (x = 0) to 140.2 K (x = 20%). The magnetocaloric effect (MCE) is significantly enhanced at higher doping levels, with the 20% Cu-doped sample exhibiting a maximum magnetic entropy change (−ΔS_M) of 2.015 J/kg-K and a relative cooling power (RCP) of 58.87 J/kg under a 60 kOe field. Arrott plot analysis confirms that the magnetic phase transitions remain second-order in nature across all compositions. These results demonstrate that Cu doping is an effective strategy for tuning the magnetostructural response of CoCr₂O₄ nanoparticles, making them promising candidates for low-temperature magnetic refrigeration applications. Full article

In food processing, non-destructive and non-invasive characterization is a powerful tool for monitoring processes and controlling quality. Cheeses consist of a large variety of products whose nutritional and sensory properties depend on the source materials, cheesemaking procedures, and biochemical transformations occurring during maturation and storage. In this study, proton magnetic resonance relaxation time correlation maps (2D ¹H-NMR T₁–T₂) are used to investigate the effect of the ripening degree on Pecorino cheese and evaluate its evolution during storage in a refrigerator under vacuum-packaging conditions. NMR relaxometry has allowed for non-invasive monitoring of packaged Pecorino cheese slices, and the results were compared with those obtained with the two widely used techniques, i.e., Differential Scanning Calorimetry (DSC) and Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR). The analysis of variance and simultaneous component analysis (ASCA), separately applied to 2D ¹H-NMR T₁–T₂ correlation maps, DSC, and ATR-FTIR data, suggests that the results obtained with the NMR approach are consistent with those obtained using the two benchmark techniques. In addition, it can distinguish cheeses stored for different durations (storage time) irrespective of their original moisture content (ripening degree), and vice versa, without opening the vacuum-package, which could compromise the integrity of the samples. Full article

Rice-field eel (Monopterus albus) slices, an important aquatic product in Southeast Asia, are prone to spoilage and deterioration during cold chain storage. In this study, the effects of a composite preservative (ε-polylysine, Vitamin C (Vc), epigallocatechin gallate (EGCG), and phloretin) on the muscle quality (color, texture, water holding capacity (WHC)) of rice-field eel slices during refrigeration storage at 4 °C for up to 7 days was investigated, and the underlying mechanism was elucidated by the integrated microbiome and metabolomics, in addition to Elisa and Low-Field Nuclear Magnetic Resonance (LF-NMR). After 7 days of storage, the WHC, shear force, and a* decreased by 11.39%, 34.37%, and 49.20% in treated samples, and by 19.18%, 38.38%, and 54.87% in control samples, respectively. The addition of the composite preservative significantly increased Hexokinase, Pyruvate kinase, and Creatine kinase, while it decreased the total viable count (TVC), total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substance (TBARS), and Lactic acid. Preservative treatment maintained the moisture content of the eel slices during storage and prevented bright red oxymyoglobin from transforming into brown metmyoglobin. Microbiota composition (especially Pseudomonas) and metabolic pathways (including amino acid and its metabolites, nucleotide and its metabolite, and organic acid and its derivatives, etc.) were obviously altered by the preservative treatment. Pseudomonas, tryptophan-aspartic acid (Trp-Asp), D-Glucose 6-phosphate, Succinic Acid, Biliverdin 1, 5-Diaminopentane, and Tyramine, etc., are potential biomarkers for the quality changes of eel slices during refrigeration. These findings provide an in-depth understanding of the improvement of the eel slice quality during refrigeration storage by the composite preservative. Full article

This study systematically investigates the magnetic ordering and magnetocaloric properties of a series of polycrystalline compounds, Gd_1-xDy_xScO₃ (x = 0, 0.1, 0.2 and 1). X-ray powder diffraction (XRD) analysis confirms that all samples exhibit an orthorhombic perovskite structure with a space group of Pbnm. The zero-field cooling and field cooling magnetization curves demonstrate a transition from antiferromagnetic to paramagnetic phases, with Néel temperatures of about 3 K for GdScO₃ and 4 K for DyScO₃. The doping of Dy³⁺ weakened long-range antiferromagnetic order and enhanced short-range magnetic disorder in GdScO₃, leading to vanished antiferromagnetic transition between 2 and 100 K for the sample of x = 0.2. Using the Arrott–Noakes equation, we constructed Arrott plots to analyze the system’s critical behavior. Both the compounds with x = 0.1 and x = 0.2 conform to the 3D-Heisenberg model. These results indicate the weakened long-range antiferromagnetic order induced by Dy³⁺ doping. Significant maximal magnetic entropy change (−Δ$S_{\mathrm{M}}^{\mathrm{M}\mathrm{a}\mathrm{x}}$) of 36.03 J/kg K at 3 K for the sample Gd_0.9Dy_0.1ScO₃ is achieved as the magnetic field changes from 0 to 50 kOe, which is higher than that of GdScO₃ (−Δ$S_{\mathrm{M}}^{\mathrm{M}\mathrm{a}\mathrm{x}}$ = 34.32 J/kg K) and DyScO₃ (−Δ$S_{\mathrm{M}}^{\mathrm{M}\mathrm{a}\mathrm{x}}$ = 15.63 J/kg K). The considerable magnetocaloric effects (MCEs) suggest that these compounds can be used in the development of low-temperature magnetic refrigeration materials. Full article

Fins are extended surfaces designed to increase heat dissipation from hot sources to their surroundings. Heat transfer is improved by utilising fins of different geometrical shapes. Fins are extensively used in automobile parts, solar panels, electrical equipment, computer CPUs, refrigeration systems, and superheaters. Motivated by these applications, this study investigates the incorporation of magnetic fields and porosity into a convective–radiative triangular fin to enhance heat transfer performance. The shooting technique is applied to study thermal profile and efficiency of the fin. It is found that the magnetic number (Hartmann number), porosity, convective, and radiative parameters reduce the thermal profile, while the Peclet number and ambient temperature increase it. Moreover, the efficiency increases with an increase in the magnetic number, porosity, convective, and radiative parameters, whereas it declines with an increase in the Peclet number and ambient temperature. Increasing the magnetic number from $0.1$ to $0.7$ leads to a $4\%$ reduction in the temperature profile. Similarly, raising the porosity parameter within the same range results in an approximate $3\%$ decrease in the thermal profile. An increase in the convective parameter from $0.1$ to $0.7$ causes about an $8\%$ decline in the thermal profile, while an elevation in the radiative parameter within the same range reduces it by approximately $2\%$. In contrast, enhancing the Peclet number from $0.1$ to $0.7$ increases the thermal profile by nearly $2\%$, and a rise in the ambient temperature within this range leads to an approximate $4\%$ enhancement in the thermal profile. Magnetised triangular fins are observed to have higher thermal transfer ability and efficiency than non-magnetised triangular fins. It is found that the incorporation of a magnetic field into a triangular fin, in conjunction with the porosity, improves the performance and efficiency of the triangular fin. Full article

We studied the influence of annealing on the magnetic properties and microstructure of ultrathin (metallic nucleus diameter ≈ 5 μm, total diameter ≈ 19 μm) Heusler-type NiMnGa glass-coated microwires prepared using the Taylor–Ulitovsky method. The as-prepared NiMnGa microwires exhibit unexpectedly strong magnetic anisotropy, characterized by a coercivity exceeding 3 kOe at room temperature. Furthermore, their Curie temperature (T_c) lies above room temperature. Additionally, a spontaneous exchange bias of approximately 120 Oe is observed in the as-prepared sample at 100 K. Annealing the microwires leads to a decrease in coercivity, spontaneous exchange bias, and T_c values. Notably, the annealing process shifts the T_c of the samples closer to room temperature, making them more suitable for magnetic solid-state refrigeration applications. Moreover, the hysteresis observed in the temperature dependence of magnetization for the samples annealed for 1 h and 2 h, along with the magnetic softening observed at around 260 K, is attributed to a first-order phase transformation. The observed changes are discussed in the context of internal stress relaxation after annealing, the nanocrystalline structure of both the as-prepared and annealed samples, the recrystallization process, and the magnetic ordering of phases identified in the as-prepared sample and those appearing during recrystallization. The glass coating on microwires offers benefits like better flexibility and resistance to damage and corrosion. However, it is important to recognize that this coating can substantially alter the microwires’ magnetic characteristics. Consequently, precise control over the annealing process is vital to obtain the specific martensitic transformation needed. Full article

This study explores the structural, magnetic, and magnetocaloric properties of ${\mathrm{Ce}}_2$(Fe, Co${)}_{17}$ (x = 0, 0.5, 0.6, and 0.7) compounds synthesized via arc melting under high temperatures exceeding 2300 K. The as-cast ingots are subsequently sealed and subjected to a heat treatment at 1323 K to improve homogeneity and crystallinity. Detailed analyses using X-ray diffraction and magnetometry reveal that cobalt substitution significantly impacts the structural and magnetic behavior, enabling precise tuning of the magnetic transition temperature and magnetic order. The substitution induces an anisotropic increase in cell parameters and shifts the magnetocaloric effect (MCE) from low temperatures (200 K for x = 0) to near room temperature (285 K for x = 0.7), enhancing the operating temperature range. The magnetocaloric effect is studied across different magnetic transitions: a metamagnetic and ferro-antiferromagnetic transition followed by a paramagnetic state in one sample, and a direct ferro-paramagnetic transition in another. The compounds exhibit a second-order magnetic phase transition, ensuring a reversible MCE, with a relative cooling power (RCP) that is approximately 85% of that of pure Gd. Moreover, the use of cerium, the most cost-effective rare-earth element (5 $/kg), combined with its low atomic concentration (10%) in these intermetallics, enhances the sustainability and affordability of these materials. These findings underline the potential of iron-rich Ce-based compounds for next-generation refrigeration and energy-harvesting applications. Full article

The development of magnetic refrigerants with both low-field responsiveness and a large magnetic entropy change in the sub-Kelvin temperature range remains a critical challenge for advancing cryogenic technologies. This study focuses on the monoclinic compound Gd₇(BO₃)(PO₄)₂O₆, in which high-density Gd³⁺ ions form magnetic frustrated structures within the bc-plane and stack along the a-axis direction. The combination of a high magnetic ion density and frustrated magnetic configuration enables the coexistence of a low magnetic transition temperature and excellent magnetocaloric effects. Magnetic susceptibility measurements reveal an antiferromagnetic-to-paramagnetic phase transition below 2 K. The maximum magnetic entropy change reaches 35.2 J kg⁻¹ K⁻¹ under a varying magnetic field of 0–7 T. This study highlights the potential of frustrated magnetic interactions in monoclinic lattices with a high Gd³⁺ content for achieving superior cryogenic magnetocaloric performance. Full article

Permanent Magnet Linear Oscillating Motors (PMLOMs) are popular in micro-positioning systems, biomedical devices, and refrigeration compressors due to their simple structure, high efficiency, rapid response, and quiet operation. This paper proposes a method for the analysis and optimization of electromechanical systems that employs a moving magnet linear oscillating motor. A simplified magnetic circuit method model was built to derive an electromagnetic thrust formula, and the initial design parameters of the motor and the thrust at the equilibrium position were calculated. Subsequently, a finite element model was developed, and a multi-objective optimization method was applied to refine the key dimensions of the motor to enhance its thrust characteristics. Furthermore, an analysis of the resonant characteristics of the electromechanical coupled system was conducted to identify the optimal operating frequency for the optimization scheme. Finally, the experimental validation of the optimized design was performed on a prototype, with the measured data showing a general correlation with the trends observed in the simulation analysis results. The effectiveness of this system analysis method was validated through experimental data. The results demonstrate that the thrust at the initial position is linearly correlated with both the outer arc radius of the permanent magnet and its mechanical pole arc coefficient. Additionally, the axial length of the outer stator, the axial spacing between the two outer stators, and the axial length of the magnets serve as key influencing parameters for the thrust characteristics within the effective stroke range. Furthermore, when the motor operates at its mechanical resonance frequency, it can attain the maximum efficiency. Full article

In the design of a rotary-type magnetic refrigerator, a high field of a coaxial magnet is desired. Typically, a high-field design can be achieved with a small duty cycle, which might not be optimized from the viewpoint of the thermal hydraulics of a magnetic refrigerator. In this work, a numerical simulation analysis of a graded coaxial magnet designed using a COMSOL program for a rotary-type active magnetic refrigeration (AMR) system was performed. The magnet structures are based on neodymium–iron–boron permanent magnets with thin gadolinium (Gd) and gadolinium-terbium alloy (Gd-Tb) plates as AMR materials. For a rotary-type magnetic cooling system, from the thermal–hydraulic point of view, the best duty cycle of a coaxial magnet should be 50% if the magnetic field can be kept constant during the period of duty cycles. However, the simulation calculation shows a serious reduction in the magnetic field strength at higher duty cycles, resulting in lower magnetic cooling efficiency. After considering the thermos-hydraulic part, the optimized duty cycle is around 30% in the case of a temperature span of 8 K between the hot and cold ends on a rotary-type magnetic cooling system. By applying graded Gd-Tb alloy along the flow direction, the performance of magnetic refrigeration improves significantly. Compared to a pure Gd AMR system, it is demonstrated that more than three times the increase in the cooling capacity can be achieved. Full article

Cryogenic magnetic refrigerants based on the magnetocaloric effect (MCE) hold significant potential as substitutes for the expensive and scarce He-3. Gd(III)-based complexes are considered excellent candidates for low-temperature magnetic refrigerants. We have synthesized a series of Ln(III)-based metal-organic framework (MOF) Ln-3D (Ln = Gd/Dy) by the slow release of oxalates in situ from organic ligands (disodium edetate dehydrate (EDTA-2Na) and thiodiglycolic acid). Structural analysis shows that the Ln-3D is a neutral 3D framework with one-dimensional channels connected by [Ln(H₂O)₃]³⁺ as nodes and C₂O₄²⁻ as linkers. Magnetic measurements show that Gd-3D exhibits very weak antiferromagnetic interactions with a maximum −ΔS_m value of 36.6 J kg⁻¹ K⁻¹ (−ΔS_v = 74.47 mJ cm⁻³ K⁻¹) at 2 K and 7 T. The −ΔS_m value is 28.4 J kg⁻¹ K⁻¹ at 2 K and 3 T, which is much larger than that of commercial Gd₃Ga₅O₁₂ (GGG), indicating its potential as a low-temperature magnetic refrigerant. Full article

The combined effects of pulsed light and a rotating magnetic field on the quality of raw pork loin stored under refrigerated conditions were studied. Muscles from the same carcass were divided into six distinct portions. Three portions were designated as untreated control samples, while the other three underwent experimental procedures involving exposure to pulsed light and a rotating magnetic field. Comprehensive laboratory analyses were conducted at specific intervals during the storage period to evaluate changes and assess the impact of storage duration on the samples. The results demonstrated that the combined use of a magnetic field and pulsed light significantly extended the shelf life of raw pork. A significant (p < 0.05) reduction in total microbial count was observed in treated samples compared to the control group throughout all storage periods. The treatment also improved all sensory attributes and reduced purge loss during refrigerated storage. Additionally, the applied treatment significantly (p < 0.05) lowered the hardness and rigidity on day 10, as well as the chewiness of the pork loin on days 1 and 10 of storage. The novelty and innovation of this study lie in the application of a rotating magnetic field combined with a pulsed light beam to enhance the properties of raw pork. This approach resulted in a synergistic effect, notably decelerating the deterioration of meat quality, extending its shelf life, and reducing energy consumption during processing. These outcomes hold significant potential for environmental, economic, and social benefits. Full article

A novel amorphous Fe₈₈Pr₆Ce₄B₂ ribbon with better magnetocaloric properties near 285 K is reported in the present work. The Fe₈₈Pr₆Ce₄B₂ ribbon exhibits a typical second-order ferromagnetic–paramagnetic transition near its Curie temperature (T_c, ~284 K), with a maximum magnetic entropy change (−ΔS_m^peak) of ~4.15 J/(kg × K) under 5 T and a maximum adiabatic temperature rise (ΔT_ad) of ~2.57 K under 5 T, both of which are almost the largest amongst the iron-based metallic glasses with T_c = 285 ± 10 K. The high −ΔS_m^peak enables several amorphous hybrids with table-like −ΔS_m–T curves to be synthesized by appropriately proportioning the Fe₈₈Pr₆Ce₄B₂ ribbon and other amorphous ribbons with different T_c. The larger average −ΔS_m and effective refrigeration capacity, as well as the appropriate temperature range, make the two amorphous hybrids potential candidates for use as refrigerants in household magnetic air conditioners. Full article

During storage and transportation, meat is susceptible to the effects of microorganisms, endogenous enzymes, and oxygen, leading to issues such as moisture loss, spoilage, and deterioration. Superchilling, as a preservation method that combines the benefits of refrigeration and freezing, can effectively slow the growth and reproduction of microorganisms, control protein and lipid oxidation, reduce water loss, and maintain the quality and sensory properties of meat. This paper reviews the current application status of superchilling technology in meat preservation, focusing on the mechanisms of ice crystal formation, water retention, tenderness preservation, protein and fat oxidation control, and microbial growth inhibition under superchilling conditions. Additionally, it summarizes the research progress on the combined application of superchilling with emerging technologies such as electric fields, magnetic fields, and electron beams in meat preservation and explores its potential and future prospects for improving meat quality. The aim is to provide scientific evidence and technical support for the application of superchilling technology in enhancing meat quality. Full article