Application Of Hydrostatic Pressure Research Articles

Pressure-induced structural stability, metallization and optoelectronic properties of transition metal chalcogenide BaTiS3

The pressure effects on the structural stability, metallization and optoelectronic properties of transition metal chalcogenide BaTiS3 are investigated by performing ab-initio calculations. Our calculations show that BaTiS3 has a hexagonal structure at ambient pressure, which matches well with the available experimental values. As pressure increases, a transition from hexagonal to orthorhombic phase occurs at around 10.8 GPa. The band structure and density of states of hexagonal BaTiS3 have been calculated and analysed. Moreover, the effect of pressure on the optical properties has been studied in terms of dielectric function as well as absorption coefficient, reflectivity and extinction coefficient. The application of hydrostatic pressure has shifted the maximum absorption toward the visible range, revealing that hexagonal BaTiS3 can be used for high pressure optoelectronic applications.

Structural Transition Analysis of Bilayer Black Phosphorus under High Pressure via Ultralow-Frequency Raman Spectroscopy.

The unique anisotropic electron-photon and electron-phonon interactions of black phosphorus (BP) set it apart from other isotropic 2D materials. These anisotropic properties can be adjusted by varying the stacking thickness and sequence as well as by applying external pressure and strain. In contrast to multilayer or bulk BP, the effects of pressure on bilayer BP are still not fully elucidated. This study presents experimental evidence that explores the high-pressure response (0-20 GPa) of bilayer BP within the extreme low Raman shift region (5-150 cm-1), aiming at verifying structural phase transitions and stacking sequence variations. Notably, phase transitions were observed at ∼7 GPa for the orthorhombic to rhombohedral transition and at ∼14-16 GPa for a further transition to a simple cubic structure. The effects of pressure on bilayer BP with three distinct stacking sequences (AA, AB, and AC) were analyzed using angular-resolved polarized Raman spectroscopy (ARPR). The recovery of all characteristic Raman modes after the application of pressure substantiates the reversibility of the structural phase transitions in bilayer BP across all three stacking sequences. However, significant alterations in the stacking sequences were observed before and after the application of hydrostatic pressure. Specifically, AA and AC stacking sequences showed a tendency to relax into an optimized interlayer AB stacking structure upon the release of pressure from 20 to 0 GPa. This observed change in the stacking sequences of bilayer BP under pressure is detected for the first time in this work. The pressure-induced modifications in the stacking sequences, and consequently in the anisotropic properties of bilayer BP, highlight its potential as a promising material for pressure- (or strain-) sensitive optoelectronic nanodevices. Additionally, this study offers novel insights into the analysis of anisotropic interlayer interactions in other van der Waals-stacked 2D materials.

Changes in the microbiota and colour of pork meat batter during refrigerated storage in relation to the application of High Hydrostatic Pressure

The aim of this work was to study the effect of High Hydrostatic Pressures (HHP) on microbial degradation pattern and colour stability of pork meat batters used to produce fresh sausages. Besides treatments at 300 or 600 MPa for 5 min, pH (5.8 vs 5.4) and nitrite addition (100 vs. 0 mg/kg) were considered as variables. A not treated control was also monitored. The different samples were stored at 4°C and periodically analysed for their microbiota and colour. At the end of shelf life (TMC > 6.5 log CFU/g) a metagenomic analysis was also carried out to better clarify the effect of the treatments on microbial spoilage patterns. The results showed that the treatment at 300 MPa slightly affected initial cell load, but slowdown growth kinetics, especially at low pH, while 600 MPa strongly reduced microbial spoilage. The application of HHP was able to prolong shelf life of meat batters, from about two weeks (control) to 40 and 80 days in the case of treatments at 300 and 600 MPa, respectively. Metagenomic analysis revealed different degradation patterns in relation to tested variables: untreated samples showed the prevalence of Brochothrix spp., while the application of HHP determined the presence also of Carnobacterium, Bacillus, and Staphylococcus, depending on the treatment and the meat batter pH. Concerning colour, differences were mainly observed in redness (a*) and were due to the presence of nitrite. These findings suggest that HHP can be a feasible strategy to stabilize fresh sausages, although further studies are needed to assess their safety.

A DFT study of the effect of hydrostatic pressure on the structure and electronic properties of sarcosine crystal

ContextWe perform density functional theory calculations to study the dependence of the structural and electronic properties of the amino acid sarcosine crystal structure on hydrostatic pressure application. The results are analyzed and compared with the available experimental data. Our findings indicate that the crystal structure and properties of sarcosine calculated using the Grimme dispersion-corrected PBE functional (PBE-D3) best agree with the available experimental results under hydrostatic pressure of up to 3.7 GPa. Critical structural rearrangements, such as unit cell compression, head-to-tail compression, and molecular rotations, are investigated and elucidated in the context of experimental findings. Band gap energy tuning and density of state shifts indicative of band dispersion are presented concerning the structural changes arising from the elevated pressure. The calculated properties indicate that sarcosine holds great promise for application in electronic devices that involve pressure-induced structural changes.MethodsThree widely used generalized gradient approximation functionals—PBE, PBEsol, and revPBE—are employed with Grimme’s D3 dispersion correction. The non-local van der Waals density functional vdW-DF is also evaluated. The calculations are performed using the projector-augmented wave method in the Quantum Espresso software suite. The geometry optimization results are visualized using VMD. The Multiwfn and NCIPlot programs are used for wavefunction and intermolecular interaction analyses.

Insights into pressure-driven depolarization in PLZST-based antiferroelectric ceramics

Materials showing field-driven antiferroelectric to ferroelectric transformation are interesting for the design of pyroelectric, high strain actuator and high-power dielectric energy storage and discharge devices. The stability of the antiferroelectric and ferroelectric states at room temperature can be chemically tuned by La and Ti co-modification of the antiferroelectric system Pb(Zr1-ySny)O3. Here, we have chosen a composition Pb0.982La0.012(Zr0.60Sn0.30Ti0.10)O3 (PLZST) at the threshold of the antiferroelectric-ferroelectric instability at room temperature and investigated the effect of electric field, temperature and pressure on the stability of the structural-polar states. We show that electric poling transforms irreversibly the antiferroelectric state into a ferroelectric state. Application of hydrostatic pressure ∼100 MPa on the field-stabilized ferroelectric phase, however, restores the antiferroelectric state and depolarizes the system.

Effects of hydrostatic pressure, osmotic pressure, and confinement on extracellular matrix associated responses in the nucleus pulposus cells ex vivo

Spinal movement in both upright and recumbent positions generates changes in physicochemical stresses including hydrostatic pressure (HP), deviatoric stress, and confinement within the intradiscal compartment. The nucleus pulposus (NP) of the intervertebral disc is composed of highly negatively charged extracellular matrix (ECM), which increases osmotic pressure (OP) and generates tissue swelling. In pursuing regenerative therapies for intervertebral disc degeneration, the effects of HP on the cellular responses of NP cells and the ECM environment remain incompletely understood. We hypothesized that anabolic turnover of ECM in NP tissue is maintained under HP and confinement. We first clarified the effects of the relationships among HP, OP, and confinement on swelling NP explants isolated from bovine caudal intervertebral discs over 12 hours. We found that the application of confinement and constant HP significantly inhibits the free swelling of NP (p < 0.01) and helps retain the sulfated glycosaminoglycan. Since confinement and HP inhibited swelling, we incubated confined NPs under HP in high-osmolality medium mimicking ECM-associated OP for 7 days and demonstrated the effects of HP on metabolic turnover of ECM molecules in NP cells. The aggrecan core protein gene was significantly upregulated under confinement and constant HP compared to confinement and no HP (p < 0.01). We also found that confinement and constant HP helped to significantly retain smaller cell area (p < 0.01) and significantly prevent the severing of actin filaments compared to no confinement and HP (p < 0.01). Thus, we suggest that NP's metabolic turnover and cellular responses are regulated by the configuration of intracellular actin and fibrillar ECMs under HP.

Analysis of Depth and Liquid Density Factor at Hydrostatic Pressure Assisted by PhET Simulation

The study has been conducted to analyze the depth factor of liquids and the density factor of liquids assisted by PhET simulation. This research is quantitative descriptive research with data presented descriptively, tables, and graphs. The data is obtained through a simulation of hydrostatic pressure in a PhET simulation. The results show that the relationship between the density of the liquid and the depth of the liquid to the pressure of the liquid is directly proportional. If the density of the liquid and the depth of the liquid are greater, the pressure will also be greater. The application of hydrostatic pressure is seen in the design of submarines which need to take into account the amount of hydrostatic pressure in the sea.

Pressure-induced extreme anisotropic behavior of thermoelectric properties in crystalline β-CuSCN

Applying hydrostatic pressure has emerged as a promising strategy for regulating the properties of thermoelectric materials, particularly in the case of β-CuSCN, which has garnered attention due to its ultra-low thermal conductivity and potential applications in thermoelectric devices. Herein, we investigate the intrinsic mechanism governing the electron-thermal transport properties of β-CuSCN under hydrostatic pressure. It was found that ZT decreased by 30 % along the in-plane direction while increasing by 24 % along the out-of-plane direction following the application of hydrostatic pressure, respectively. Our results reveal that the competitive relationship between pressure-driven effects on phonon dynamics and electronic structure influences the thermoelectric properties of β-CuSCN. For the transport mechanism, the compression alters phonon dispersion by enhancing atomic interactions, which leads to an increase in lattice thermal conductivity. On the other hand, despite strong coupling between electrical transport parameters, a net increase in power factor is achieved through pressure-induced bandgap narrowing. As a result, the thermoelectric properties demonstrate contrary variation tendency along the in-plane and out-of-plane directions. Our research deepens our understanding of transport behavior under extreme pressure conditions and provides valuable insights into the fundamental relationship between structural deformation and thermoelectric performance.

Strains in sprayed concrete tunnel linings at Heathrow Terminal 4 and back-calculation of stress

This paper describes the installation and interpretation of strain gauges embedded in the sprayed concrete lining of the concourse tunnel at Heathrow Terminal 4 station, with readings taken over nearly 20 years. The rate of flow method was used to back-calculate stresses from the measured strains, which were then compared to stresses obtained from pressure cells at the same locations. The interpretation of the pressure cell data is described in Jones &amp; Clayton (2021) and the pressure cell results were presented in Jones et al. (2023). The resulting 20-year history of stress and strain gives precious insights into the short- and long-term behaviour of a sprayed concrete lining. An increase of compressive strain up to 3 years followed by a slight decrease over the subsequent 15-16 years has been revealed. It is hypothesised that this is due to radial groundwater flow through the primary lining followed by the gradual application of hydrostatic water pressure to the waterproof membrane and secondary lining. The sprayed concrete primary lining was not designed for permanent loads but nevertheless appears to be supporting all of the effective stress, whereas the secondary lining is not supporting any ground loads but may be loaded by groundwater pressure.

Effects of Thermally-Assisted and High-Pressure Processing on Background Microbiota and the Listeria monocytogenes Load of a Minimally Processed Commodity.

The current study investigated the impact of treatments with elevated hydrostatic pressure (500 MPa) for inactivation of Listeria monocytogenes on smoked rainbow trout (Oncorhynchus mykiss) at high and low inoculation levels. The temperature values of the trials were set at 4.4 and 60.0 °C, adjusted with a circulating water bath connected to a stainless steel jacket surrounding the pressure processing chamber. Before pressure processing, the counts (selective counts of PALCAM, mean ± SD) of L. monocytogenes were 6.45 ± 0.1 log CFU/g and were reduced (p < 0.05) to 3.72 ± 0.3, and <1.48 ± 0.8 log CFU/g after 10 min of treatment at 4.4 and 60.0 °C, respectively. Treatments of low inoculation level samples were similarly efficacious and resulted in a reduction (p < 0.05) of the pathogen to 1.62 ± 0.3 and <0.82 ± 0.0 log CFU/g for treatments at 4.4 and 60.0 °C, respectively. At 4.4 °C, linear D-value and non-linear kmax1 were 8.68 and 0.50, and 5.81 and 2.41 for high-inoculation and low-inoculation samples, respectively. Application of hydrostatic pressure at 500 MPa at cold and elevated temperatures was efficacious for up to 5.03 log CFU/g reduction of L. monocytogenes, illustrating the potential for further adaptation of this technology.

Calculation of the mobility-lifetime product of charge carriers in cubic CsPbX3 (X = Cl, Br, I) perovskites under pressure

In recent years, there has been a growing interest in using inorganic halide perovskites for designing gamma-ray and X-ray detectors. To select the appropriate perovskite for detector design, it is important to consider the mobility-lifetimes (μτ) product of the charge carriers. A high value of the μτ product increases charge collection and simplifies detector construction. It is worth noting that the application of hydrostatic pressure can cause changes in the crystal structure, which affect the physical properties and value of the μτ product. This paper focuses on investigating the μτ product of charge carriers in the cubic phase of CsPbX3 (X = Cl, Br, I) perovskites under different hydrostatic pressures. Calculations are performed using a method based on the deformation potential theory. The results show that with increasing pressure, CsPbI3 perovskite shows a huge increase in the μτ product. Specifically, under pressure up to 6 GPa, the μτ product for electrons and holes increases by a factor of 233.8 and 1764.7, respectively, with respect to zero pressure. Additionally, calculations of their optical properties have revealed that these materials can be used in UV light detectors and photovoltaic devices.

A theoretical analysis of the effect of hydrostatic pressure on cerium oxide for renewable energy applications

The characteristics of cubic cerium oxide (CeO2) have been investigated using density functional theory (DFT) using the PBE-GGA exchange–correlation functional. This study mainly focused on the structural, elastic, and optoelectronic properties of the CeO2 under the application of external hydrostatic pressure. It is observed that lattice constants and volume tend to decrease with increasing pressure. Based on the observed trends in lattice constants variations, CeO2 exhibits compressibility at high-pressure conditions, although it remains structurally unchanged throughout the pressure range of 0 to 100 GPa. Applying pressure within the range of 0 to 100 GPa reveals a distinct characteristic associated with the emergence of electronic bandgap opening. The material displays an indirect energy bandgap, with its magnitude increasing from 2.659 eV to 4.055 eV under rising pressure. To deeply understand the impact of external pressure on the optical behaviour of CeO2, extensive investigation has been conducted on several optical parameters such as the dielectric function, refractive index, optical reflectivity, absorption coefficient, optical conductivity, and loss function throughout the energy range up to 50 eV. However, there is a tendency for optical parameters to show sharpening peaks that shift somewhat towards higher energies. Furthermore, we have also tested the impact of bandgap modulation induced in CeO2 by proposing a CsSnBr3-based solar cell with the One-Dimensional Solar Cell Capacitance Simulator software. Based on our findings, the use of cubic cerium oxide may find its potential to enhance the performance of optoelectronic and renewable energy devices.

Application of High Hydrostatic Pressures and Refrigerated Storage on the Content of Resistant Starch in Selected Legume Seeds

Application of High Hydrostatic Pressures and Refrigerated Storage on the Content of Resistant Starch in Selected Legume Seeds

(Invited) Exploring and Manipulating Luminescence Centers in Lead Halide Perovskites through Hydrostatic Pressure

The application of hydrostatic pressure to materials induces changes in lattice constants, vibrational spectra, and electron-phonon interactions, thereby altering the optoelectronic properties of semiconductors. Consequently, hydrostatic pressure has become a widely utilized tool for investigating and enhancing the optical properties of organic/inorganic halide perovskites and their nanostructures. In this presentation, I will discuss the impact of hydrostatic pressure on two distinct types of luminescence centers in perovskite materials. The first type of luminescence centers originates from excitons within perovskite nanocrystals. I will discuss how hydrostatic pressure serves as a valuable tool for elucidating the origin of luminescence in low-dimensional perovskites, including 2D CsPb2Br5, 0D Cs4PbBr6, and 2D Ruddlesden-Popper Hybrid Perovskite Crystals. The second type of luminescence centers exhibit broadband optical emission from self-trapped excitons in low-dimensional perovskites. I will present our findings on the observation of strong exciton-phonon coupling and demonstrate how hydrostatic pressure can be employed to modulate electron-phonon coupling, offering a means to finely tune the broad emission spectrum.

Investigation of the electronic properties of a topological semimetal LaAuPb under uniaxial strain and hydrostatic pressure: A DFT approach

In this study, we utilized first-principles calculations to investigate the structural, electronic, mechanical, and vibrational properties of the topological semimetal LaAuPb. Our research delves into how uniaxial strain and hydrostatic pressure influence the electronic band structure of LaAuPb. We discovered that LaAuPb exhibits ductile behavior and maintains dynamic stability under various conditions. Upon introducing compressive strains of −6%, we observed a significant separation of degenerate states at the gamma point, which consequently led to the formation of a band gap. Similarly, the application of hydrostatic pressure at 16 GPa also resulted in the creation of a band gap by altering the electronic band structure. These findings suggest that both compressive strain and hydrostatic pressure can be effective in modulating the electronic properties of LaAuPb, potentially making it useful for applications requiring tunable electronic behavior. Conversely, when subject to tensile strain, no band gap formation was observed. Instead, there was a notable gradual overlap between the valence and conduction bands, indicating that tensile strain does not induce the same electronic separations as compressive strain or hydrostatic pressure. This asymmetrical response to different types of strain underscores the complex nature of LaAuPb's electronic properties and provides valuable insights for its potential use in electronic and mechanical applications. Overall, our findings contribute to the understanding of how external mechanical forces can be harnessed to control the electronic properties of topological semimetals like LaAuPb.

Pressure-induced structural, electronic, optical, and mechanical properties of lead-free GaGeX3 (X = Cl, Br and, I) perovskites: First-principles calculation

Researchers are now focusing on inorganic halide-based cubic metal perovskites that are not toxic as they strive to commercialize optoelectronic products and solar cells derived from perovskites. This study explores the properties of new lead-free compounds, specifically GaGeX3 (where X = Cl, Br, and I), by executing first-principles Density Functional Theory (DFT) to analyze their optical, electronic, mechanical, and structural characteristics under pressure. Assessing the reliability of all compounds is done meticulously by applying the criteria of Born stability and calculating the formation energy. As discovered through elastic investigations, these materials showed anisotropic behavior, flexibility, and excellent elastic stability. The electronic band structures, calculated using both HSE06 and GGA-PBE functionals at 0 GPa, reveal fascinating behavior. However, computed band structures with non-zero pressures using GGA-PBE. Here, the conduction band moved to the lower energy when the halide Cl was changed with Br or I. In addition, the application of hydrostatic pressure can lead to tunable band gap properties in all compounds such as from 0.779 eV to 0 eV for GaGeCl3, from 0.462 eV to 0 eV for GaGeBr3 and from 0.330 eV to 0 eV for GaGeI3, resulting transformation from semiconductor to metallic. Understanding the origins of bandgap changes can be illuminated by examining the partial and total density of states (PDOS & TDOS). When subjected to pressure, all the studied compounds showed an impactful increase in absorption coefficients and displayed exceptional optical conductivity in both the visible and UV zones. Yet, GaGeCl3 is a more effective UV absorber because it absorbs light more strongly in the UV area. Moreover, GaGeI3 stands out among the compounds examined due to its impressive visible absorption and optical conductivity, which remain consistent under varying pressure conditions. Besides, GaGeI3 exhibits higher reflectivity when subjected to pressure making them suitable for UV shielding applications. At last, these metal cubic halide perovskites without lead present promising opportunities for advancing optoelectronic technologies. With their tunable properties and favorable optical characteristics, these materials are highly sought after for their potential in solar cells, multi-junctional solar cells, and different optoelectronic functions.

The Influence of High Hydrostatic Pressure on Selected Quality Features of Cold-Storage Pork Semimembranosus Muscle.

The primary objective of this investigation was to assess the influence of high hydrostatic pressure (HHP) and the duration of cold storage on the physicochemical, technological, and sensory attributes as well as the nutritional composition and shelf life of meat. The experimental framework involved utilizing samples derived from the semimembranosus muscle of pork. Each muscle obtained from the same carcass was segmented into six distinct parts, with three designated as control specimens (K) and the remaining subjected to vacuum packaging and subsequent exposure to high hydrostatic pressure (200 MPa at 20 °C for 30 min). Comprehensive laboratory analyses of the meat were conducted at 1, 7, and 10 days post slaughter. The meat was cold-stored at +3 ± 0.5 °C. The findings of the study elucidated that the application of high hydrostatic pressure exhibited a favorable impact on the extension of the raw meat's shelf life. The tests showed a significant (p < 0.05) decrease in the total number of microorganisms compared to the control sample after 7 (K: 4.09 × 105, HHP: 2.88 × 105 CFU/g) and 10 (K: 7.40 × 105, HHP: 2.42 × 105 CFU/g) days of cold storage. It was also found that using HHP increased the pH value after 1 (K: 5.54, HHP: 5.77) and 7 (K: 5.60, HHP: 5.87) days of storage.

Experimental study on coupled caloric effect driven by dual fields in metamagnetic alloy ErCo2

This study presents an experimental investigation of the coupled caloric effect driven by dual-fields in metamagnetic alloy ErCo2 with strong magneto-structural coupling. Magnetic measurements were conducted under different pressures, revealing that the application of hydrostatic pressure stabilizes a small volume of paramagnetism (PM) phase, resulting in a shift of the phase transition temperature towards the low-temperature region. This shift is opposite to the temperature associated with the magnetic field-driven phase transition. As pressure increases, the metamagnetic transition in ErCo2 is suppressed, and the hysteresis disappears. However, the produced cross-coupling caloric effect compensates the decrease in entropy change caused by the disappearance of the metamagnetic transition. As a result, a reversible giant magnetocaloric effect of 46.2 J/(kg·K) without hysteresis is achieved at a pressure of 0.910 GPa. Moreover, we propose that the temperature span of ErCo2 can be significantly widened by optimizing the thermodynamic pathway of the magnetic and pressure fields, overcoming the defect of a narrow temperature range.

Investigation of high-pressure effect on the physical properties of FrNBr3 (N[dbnd]Ca, Sr) non-toxic halide perovskites

Utilizing ab-initio modeling, this study analyzes the possibility of replacing Lead with Francium halide perovskite for use in potential photovoltaic or optoelectronic device applications. Density functional theory is employed to estimate the structural, electronic, bonding, optical, anisotropic elastic, and mechanical characteristics of FrNBr3 (NCa, Sr) at various hydrostatic stresses scaling from 0 to 80 GPa. The calculation of the tolerance factor validates the structural stability. At 0 GPa pressure, the computed lattice constants for FrCaBr3 and FrSrBr3 are 5.78 Å (5.38 Å) and 6.03 Å (5.62 Å), respectively, using GGA (HSE03) approximation potential. FrNBr3 (NCa, Sr) perovskites show increased band gap values using the HSE03 method. Notably, these HSE03-derived values align with the trends observed in the GGA-PBE scheme, under both normal and hydrostatic pressure conditions. As pressure increases, both the lattice constant and unit cell volume decrease significantly. The estimated direct band gaps demonstrate the semiconducting nature of the compounds under ambient pressure. However, when pressure increases, the band gap narrows, increasing conductivity, and makes it as one of the great contenders of microelectronics as well as tandem photovoltaics due to its shift from ultraviolet to visible light energy region. Applying pressure enhances the optical properties, showcasing its utility in various semiconductor applications within the visible ranges and overcoming its limited usage in the ultraviolet domain. In the same vein, the application of hydrostatic pressure significantly impacts mechanical properties without compromising stability. The ductile and anisotropy character become more pronounced when pressure is exerted.

Pressure control of magnetic order and excitations in the pyrochlore antiferromagnet MgCr2O4

MgCr2O4 is one of the best-known realizations of the pyrochlore-lattice Heisenberg antiferromagnet. The strong antiferromagnetic exchange interactions are perturbed by small further-neighbor exchanges such that this compound may in principle realize a spiral spin liquid (SSL) phase in the zero-temperature limit. However, a spin Jahn-Teller transition below TN≈13 K yields a complicated long-range magnetic order with multiple coexisting propagation vectors. We present neutron scattering and thermomagnetic measurements of MgCr2O4 samples under applied hydrostatic pressure up to P=1.7 GPa demonstrating the existence of multiple close-lying nearly degenerate magnetic ground states. We show that the application of hydrostatic pressure increases the ordering temperature by around 0.8 K per GPa and increases the bandwidth of the magnetic excitations by around 0.5 meV per GPa. We also evidence a strong tendency for the preferential occupation of a subset of magnetic domains under pressure. In particular, we show that the k=(0,0,1) magnetic phase, which is almost negligible at ambient pressure, dramatically increases in spectral weight under pressure. This modifies the spectrum of magnetic excitations, which we interpret unambiguously as spin waves from multiple magnetic domains. Moreover, we report that the application of pressure reveals a feature in the magnetic susceptibility above the magnetostructural transition. We interpret this as the onset of a short-range ordered phase associated with k=(0,0,1), previously not observed in magnetometry measurements. Published by the American Physical Society 2024