Showing papers in "High Pressure Research in 2023"
TL;DR: In this article , the authors used synchrotron radiation X-ray diffraction to study the equation of state of vanadium nitride in a diamond anvil cell at room temperature.
Abstract: ABSTRACT In this study, synchrotron radiation X-ray diffraction is used to study the equation of state of vanadium nitride in a diamond anvil cell at room temperature. Experimental results reveal the high stability of the cubic structure up to 76 GPa pressure. In addition, the bulk modulus of vanadium nitride derived from XRD data is K 0 = 328.4(2.8) GPa with K 0′ = 5.86(0.14). Finally, the high pressure compression behavior is investigated to 80 GPa using density functional theory of first-principle calculations, and the obtained bulk elastic modulus is 316 GPa. Vanadium nitride is not magnetic in the whole pressure range and is metallic. Highlights • We have investigated the equation of state of VN under high pressure with silicone oil as the pressure transmitting medium to 76 GPa. • It was found that the face-centred cubic structure of VN maintains the maximum pressure of 76 GPa. • We have carried out first-principles calculations and obtained the equation of state, band structure, and electronic density of state of VN to 80 GPa.
TL;DR: In this article , the salting and slight drying combination has synergistic impacts on alleviation of fish quality changes after pressurization, e.g. muscle semi-transparency, lower lightness, and stronger water-holding capacity.
Abstract: ABSTRACT High pressure can induce significant sensory quality changes in fish. Considering the important role of raw attributes in ready-to-eat aquatic products, our study thus focused on combination treatments prior to pressurization, to maintain grass carp quality. Fish fillets with or without salting and/or slight drying were pressurized under 0.1, 300, 400, and 500 MPa for 10 min. Microbiological, sensorial, and chemical analyses were performed to assess fish quality. The salting and slight drying combination have synergistic impacts on alleviation of fish quality changes after pressurization, e.g. muscle semi-transparency, lower lightness, and stronger water-holding capacity. This could be associated with enhanced fibrous interconnection and protein structure (less decrease of α-helix contents, less amino acid residue exposures). By contrast, fillets without pretreatments, or after single salting or drying process, had unfavorable quality alterations after pressurization. Therefore, appropriate means for developing novel ready-to-eat products can be carried out by targeting pressure-sensitive aquatic foods.
TL;DR: In this article , the authors report the development of a collection of computer programs for sound speed measurements using the ultrasound pulse-echo technique, compatible with stepped multi-frequency, as well as broadband-pulse, couplant-corrected methods.
Abstract: ABSTRACT Sound speed and elastic constants measurements in solids and liquids are commonly performed using the ultrasound pulse-echo technique. Recent advances have expanded the use of this technique at numerous high pressure synchrotron beamlines and offline laboratories. However, the increased experimental throughput has revealed many limitations in existing software for handling the rapid measurement and the subsequent data-reduction. We report the development of a collection of computer programs for sound speed measurements using the ultrasound pulse-echo technique, compatible with stepped multi-frequency, as well as broadband-pulse, couplant-corrected methods. The programs provide a highly interactive graphical interface, enable efficient measurement, exploration and near real-time analysis of the ultrasound data, and contain features useful for working with samples under high pressure and/or high temperature. The included analysis programs can alleviate the time required for data reduction from hours to less than a minute, allowing users to make timely and informed decisions regarding the appropriate experimental parameters.
TL;DR: In this article , an in situ Raman study of Na4Ca(CO3)3 carbonate up to 11 GPa was performed to reveal stability of its structure at mantle pressures.
Abstract: Na-Ca double carbonates were found as the inclusions in ‘superdeep’ Juina diamonds and as the products of high pressure experiments and thus are regarded as the potential host of CO2 in the deep mantle. Recently, Na-rich carbonate (21.0% wt. of Na2O vs. 13.6% wt. of CaO) was reported as the product of experiment with carbonated eclogite treated at 21 GPa and 1200°C. Na/Ca ratio of this carbonate corresponds to Na4Ca(CO3)3 phase with cubic symmetry synthesized at 6 GPa. The stability of Na4Ca(CO3)3 at higher pressures has not been investigated yet. Herein, we report an in situ Raman study of Na4Ca(CO3)3 carbonate up to 11 GPa in order to reveal stability of its structure at mantle pressures. Obtained results strongly imply for reversible phase transition near 8 GPa associated with decrease of symmetry. The observed phase transition questions the stability of cubic Na4Ca(CO3)3 under conditions of mantle transition zone.
TL;DR: In this article , a combination of vacuum heat sealing (VS) and/or high hydrostatic pressure treatment (HHP) was used to impregnate carrots with pigment solution by using electrical impedance spectroscopy and texture analysis.
Abstract: ABSTRACT Carrot was impregnated with pigment solution by vacuum heat sealing (VS) and/or high hydrostatic pressure treatment (HHP; 100–600 MPa, 25°C, 5 min). Impregnation efficacy was evaluated as impregnation ratio (%) by image analysis, while damages of cell membrane and texture were quantified by electrical impedance spectroscopy and texture analysis, respectively. Combinations of VS and HHP exclusively achieved 100% impregnation. Meanwhile, the damages were comparable between the samples after VS and VS + 100 MPa treatment and aggravated by elevated levels of HHP. As for the texture, breaking stress (hardness) decreased after VS and VS + HHP (100–600 MPa) comparably. Meanwhile, breaking strain (deformability) significantly increased after VS + HHP (200–600 MPa), indicating further damage of strain texture as compared with that after VS and VS + 100 MPa treatments. It was indicated that impregnation of carrot was fully achieved by a combination of VS and 100 MPa treatment, while minimizing the cell membrane and texture damages. Difference in the impregnation efficacy between carrot and apple was discussed based on their image data.
TL;DR: In this paper , the equation of state and optical properties of liquid nitrogen (LN2) were analyzed using a two-stage light-gas gun at pressure up to 29 GPa.
Abstract: ABSTRACT
We report the equation of state and optical properties of shock-compressed liquid nitrogen (LN2) by using a two-stage light-gas gun at pressure up to 29 GPa. Laser velocimetry measurements were used to investigate the transparency and refractive index of shocked LN2 as a function of density. As the density increased with increasing pressure and temperature (13–25 GPa), the refractive index increased up to 27% of pre-shot index of LN2. Evidently, such extreme conditions had no major influence on molecules, and no such dissociation was observed up to 25 GPa. The polarizability slightly decreased and thus supported the existence of intact diatomic molecular nitrogen. At 29 GPa, shocked LN2 dissociated, showing that it probably changed to a highly reflecting fluid. Altogether, these experiments showed how the density affects the refractive index without any change in chemical bonding and allocates the condition at which the temperature-driven dissociation takes place.
TL;DR: In this article , the authors investigated catechin retention potency via high hydrostatic pressure (HHP) and thermal treatment, and found that HHP showed a smiling curve relationship with catechins, with the highest levels found at 200 and 800 MPa.
Abstract: ABSTRACT Green tea catechins can improve human health, and their retention during processing is a concern. High hydrostatic pressure (HHP) blanching is a nonthermal processing that can increase both nutrients and flavor in tea. Thermal blanching retains catechins but decreases nutrients and flavor. We investigated catechin retention potency via HHP and thermal treatment. Fresh green tea leaves were pressurized at 100–800 MPa and/or heated for 10 min at 40°C–70°C and then stored for 24 hours. Tea catechin content was drastically reduced after storage without HHP, which yielded a 1.5–8.0-fold increase. HHP showed a smiling curve relationship with catechin retention, with the highest levels found at 200 and 800 MPa. Synergistic effects of HHP on thermal processing were found at 40°C–50°C but not at 60°C–80°C. Processing at 200 MPa combined with 50°C yielded 88% catechin retention. Our results suggest this combination as an optimal strategy for retaining tea catechins, nutrients, and flavor.
TL;DR: hpMCA as mentioned in this paper is a Python-based graphical program for energy-dispersive X-ray diffraction (EDXD) data collection and analysis that streamlines the experimental process for the beamline users.
Abstract: Energy-dispersive X-ray diffraction (EDXD) at synchrotron beamlines is commonly used for the study of material properties under high pressure and/or high temperature. Experimenters typically rely on the availability of robust data collection and analysis at a beamline, but this has become increasingly difficult, especially with the introduction of multi-element detectors that generate complex, multi-dimensional data sets. These data sets have energy resolution, and they can also be resolved in relation to sample position, diffraction angle, or different external stimuli. We report a new Python-based graphical program, hpMCA, for EDXD data collection and analysis that streamlines the experimental process for the beamline users. The program features a user-friendly interface, capability for online viewing and analyzing data from multi-element energy-dispersive detectors, and includes features useful for working with samples under high pressure and/or high temperature, such as crystal phase identification, real-time unit cell lattice refinement, and pressure determination based on an equation of state.
TL;DR: In this paper , a 3D Finite Element Analysis model was developed to describe the temperature distribution inside a novel neutron transparent high-pressure sample assembly, which was used to evaluate the sample assembly's temperature gradients and optimise its geometry and components.
Abstract: A 3D Finite Element Analysis model was developed to describe the temperature distribution inside a novel neutron transparent high-pressure sample assembly. The validity of the model was established by conducting experimental validation. The Finite Element Analysis model was utilised to evaluate the sample assembly’s temperature gradients and optimise its geometry and components. The results indicate that the discrepancy between the temperature recorded in the laboratory using thermocouples and the temperature calculated by the Finite Element Analysis model was only 4% under the assumption that the thermocouple was positioned in the middle of the sample assembly. The models further demonstrate that the Finite Element Analysis approach is a valuable tool for optimising the sample assembly by considering the impact of different materials and variations in the shape of its components.
TL;DR: In this paper , a predictive model based on the Box-Behnken design was developed to determine the effect of high hydrostatic pressure (HHP), temperature, and cycles (each holding time of 10 min) on the inactivation of Aspergillus niger spores and in the droplet size of a model emulsion.
Abstract: ABSTRACT A predictive model based on the Box–Behnken design was developed to determine the effect of high hydrostatic pressure (HHP), temperature, and cycles (each holding time of 10 min) on the inactivation of Aspergillus niger spores and in the droplet size of a model emulsion. The obtained model presented goodness of fit to the data with a high correlation coefficient (R2 = 0.91) and adjusted correlation coefficient value ( 0.88), with no significant lack-of-fit test (p = 0.6031). The canonical analysis provides the conditions (37.29 °C, 263.33 MPa, and, 1.88 cycles) to reduce 5.0 Log10 CFU/mL of A. nigger. Under such conditions, emulsions exhibited a monomodal distribution of droplet size. However, as temperature and pressure increased, both the PDI, D3,2, and D4,3 values increased (p ≤ 0.05). In conclusion, the proposed model has the potential to predict the reduction of A. niger spores by HHP without causing emulsion destabilization.
TL;DR: In this paper , the authors measured the thermal diffusivity and conductivity of platinum and MgO periclase at high pressures (P) and high temperatures (T) by combining the pulsed light heating thermoreflectance technique with a laser-heated diamond anvil cell.
Abstract: ABSTRACT We have measured the thermal diffusivity and conductivity of platinum and MgO periclase at high pressures (P) and high temperatures (T) by combining the pulsed light heating thermoreflectance technique with a laser-heated diamond anvil cell. The obtained thermal conductivity of platinum shows positive pressure and temperature dependences, reaching about 210 W/m/K at the highest P–T condition of 125 GPa and 1850 K. The thermal conductivity of periclase was determined up to 140 GPa and 1950 K, corresponding to the Earth's lowermost mantle, where the conductivity was about 90 W/m/K. Our measurements allow us to test models for the combined P–T dependence of the thermal conductivity of both metals and insulating materials up to Mbar pressures and thousands of kelvins.
TL;DR: In this article , the use of commercial high-power light emitting diodes (LEDs) as a light source for fluorescence pressure measurements was discussed, and it was shown that a relatively broad light emitting spectra of single color LEDs do not prevent producing narrow fluorescence lines at least for two widely used pressure indicator materials, namely ruby (Cr$^{3+}$:Al$_2$O$_3$) and strontium tetraborate (Sm$^{2+}/$:SrB$_4$ O$_7$).
Abstract: We discuss the use of commercial high-power light emitting diodes (LEDs) as a light source for fluorescence pressure measurements. A relatively broad light emitting spectra of single color LEDs (in comparison with lasers) do not prevent producing narrow fluorescence lines at least for two widely used pressure indicator materials, namely ruby (Cr$^{3+}$:Al$_2$O$_3$) and strontium tetraborate (Sm$^{2+}$:SrB$_4$O$_7$). Strongest responses of both pressure indicators were detected for the green color LEDs with the average wavelength $\lambda_{\rm av}\sim 530$ nm. LEDs might be easily implemented for producing fiber coupled, as well as the parallel light sources. LEDs were found to be efficient to replace laser sources in piston-cylinder cell and diamond anvil cell fluorescence pressure measurement setups.
TL;DR: In this article , the authors describe the thermal equation of state (EoS) model used by Dioptas and show how existing thermal EoS should be reparameterised so as to be used correctly in DioptAs.
Abstract: ABSTRACT Dioptas is a widely used software package for integrating and analysing 2-dimensional diffraction images. To help interpret the integrated diffraction profiles it produces, Dioptas users can input files that parameterise a material's thermal equation of state (EoS), enabling the positions of the Bragg peaks from that material to be calculated as a function of pressure and temperature. However, care is needed to ensure that these input files correctly describe the thermal EoS of interest. Here we describe the thermal EoS model used by Dioptas and show how existing thermal EoS should be reparameterised so as to be used correctly in Dioptas. Input EoS files suitable for use with Dioptas are provided for the following commonly-used pressure calibrants and pressure transmitting media: Al, Au, Cu, Mo, Nb, Pt, Ta, hcp-Fe, MgO, NaCl-B1, NaCl-B2, KCl-B2, and Ne.
TL;DR: In this paper , a non-magnetic uniaxial pressure cell has been designed for magnetic measurements in SQUID magnetometer, where a sample can be compressed by force up to 3 1/kN in direction perpendicular to external magnetic field.
Abstract: ABSTRACT A versatile type of non-magnetic uniaxial pressure cell has been designed for magnetic measurements in SQUID magnetometer. An advanced technology of machining of miniature parts of the cell was used to make new type of an internal squeezer module, where a sample can be compressed by force up to 3 kN in direction perpendicular to external magnetic field. A correct operation of the cell was tested by study of magnetic behaviour of the Heusler off-stoichiometric Ni2MnSn alloy under uniaxial compression. An unexpected significant difference between reversible effects of uniaxial compression on magnetization of the austenite and martensite phases of the alloy is discussed. The uniaxial compression effects are compared with the effects of hydrostatic pressure on a coupling between magnetization and structural transformation of the alloy.