Influence Of Hydrostatic Pressure Research Articles

Synergy analysis of tribocorrosion behaviour of aluminum alloy under different hydrostatic pressures

Static corrosion, tribocorrosion tests, and potentiostat polarization tests were carried out on aluminum alloy 7075-T6 in 3.5 wt.% NaCl solution. The influence of hydrostatic pressure on the tribocorrosion of the aluminum alloy in 3.5 wt.% NaCl solution was studied, and the synergy relationship between its corrosion and wear was quantitatively analyzed. The results showed that the material loss of the aluminum alloy was not simply a superposition of corrosion and wear. The wear rate of corrosion-accelerated wear increased with the hydrostatic pressure, and when the hydrostatic pressure increased from 0.1 MPa to 30 MPa, the contribution of corrosion-accelerated wear increased by 15.43%. This research will help provide theoretical support for the selection of materials for deep-sea equipment.

The impact of hydrostatic pressure on fractional flow reserve in saphenous vein grafts

Abstract Background Intracoronary physiological measurements can be subject to the influence of hydrostatic pressure. Saphenous vein grafts (SVGs) diverge in origin and trajectory from native coronary arteries, which may increase the susceptibility of fractional flow reserve (FFR) measurements to be impacted by the hydrostatic pressures. The precise impact of SVG anatomy on physiological pressure indices remains unknown at present. Purpose We sought to study the impact of SVG anatomy on FFR. Methods Included were symptomatic patients with prior coronary artery bypass grafting and at least one non-occluded SVG, who underwent coronary computed tomography angiography (CCTA) preceding invasive coronary angiography. SVG course and height excursion were reconstructed based on the CCTA images. Similarly to native coronary arteries, the impact of hydrostatic pressure on FFR was calculated by adding 0.077 mmHg to the distal coronary pressure for every millimeter height difference in a supine position between the SVG ostium and the position of the pressure wire tip. Results In total, 74 patients (mean age 71 ± 7 years; 85% male) with 87 SVGs were included. A total of 76 SVGs underwent interrogation by FFR. The height difference between SVG ostium and pressure wire tip position was largest for single SVGs to the circumflex artery (Cx; - 55.1 ± 17.0 mm), followed by sequential SVGs to the Cx (- 53.1 ± 17.7 mm) and to the right coronary artery (RCA; - 36.7 ± 21.6 mm). Corrected FFR was significantly lower as compared to uncorrected FFR in single SVGs to the Cx (0.85 ± 0.17 vs. 0.90 ± 0.18), and sequential SVGs to the Cx (0.92 ± 0.14 vs. 0.96 ± 0.15) and the RCA (0.82 ± 0.20 vs. 0.85 ± 0.21) (P<0.001 for all). Conclusions Hydrostatic pressure related to the course anatomy of SVGs notably affects FFR values, resulting in an overestimation of FFR in SVGs to the Cx and sequential SVGs to the RCA. In these SVGs, FFR values near the cutoff value should be interpreted cautiously.

The effect of deep-sea pressure during long-term aging on the tribological performance of fabric-reinforced phenolic composites

The influence of hydrostatic pressures up to 30 MPa on the friction and wear behavior of fiber reinforced polymer composites (FRPCs) was investigated together with seawater absorption, interfacial structure and mechanical properties. The results revealed that after aging in the deep-sea environment, the wear rate of the FRPC increased from 1.53 × 10−6 mm3/N∙m to 3.61 × 10−6 mm3/N∙m, and the mechanical strength decreased reversibly. The damage mechanism was assumed to be dominated by the combined effect of crack propagation in the polymer matrix and interfacial debonding at high seawater pressures, characterized by a decreased resin modulus and increased interfacial thickness.

Density Functional Theory Study of Lanthanide Monoxides under High Pressure: Pressure-Induced B1–B2 Transition

Using density functional theory, we study the influence of hydrostatic pressure on the crystal structure of lanthanide monoxides, focusing on the monoxides formed by the fifteen elements of the lanthanide series, from La to Lu. Calculations are performed using two methods for the ambient pressure B1 (NaCl type) structure, the general gradient approximation (GGA) and the local density approximation (LDA). Through a systematic comparison with existent experimental data, we find that the first method agrees better with the experiments. In addition, considering other cubic structures previously reported for lanthanide monoxides, as B2 (CsCl type) and B3 (ZnS type), we explore the possibility of the occurrence of pressure-induced phase transitions. Based on the better accuracy of GGA to describe the B1 phase at ambient conditions, we exclusively use GGA for the high pressure study. We find, for the fifteen studied compounds, that, at ambient pressure, the B1 structure is the one with the lowest enthalpy, being therefore the most thermodynamically stable structure. We also determine that, at elevated pressures, all the studied compounds undergo a structural phase transition to the B2 phase. We finally establish the relationship between pressure and volume of the unit cell, along with the associated isothermal equation of state, determining the bulk modulus.

Influence of deep-sea hydrostatic pressure on the tribocorrosion behavior and mechanism of La2O3–TiB2–Ni coating

To understand the tribocorrosion mechanism of TiB2–Ni coating doped with La2O3 in the deep ocean, the wear and corrosion test of La2O3–TiB2–Ni under various hydrostatic pressures was conducted and discussed in 3.5 wt % NaCl solution. The results indicate that the tribocorrosion mechanism of the La2O3–TiB2–Ni coating transitions from abrasive wear with corrosion under 0.1 MPa to abrasive wear with corrosion and adhesive wear under high hydrostatic pressure. The La2O3–TiB2–Ni coating shows significant enhancements in wear resistance and anti-friction properties compared to the TiB2–Ni coating. As the hydrostatic pressure increases from 0.1 MPa to 30 MPa, the self-corrosion current density experiences an approximate increase of 43.6 μA/cm2.

The influence of hydrostatic pressure on the synthesis of colloidal core-shell quantum dots with the mismatch of lattice parameters

The influence of hydrostatic pressure on the synthesis of colloidal core-shell quantum dots with the mismatch of lattice parameters

The Impurity States in Different Shaped InxGa1-xAs/GaAs Quantum Wells under the Influence of Temperature and Hydrostatic Pressure

The Impurity States in Different Shaped InxGa1-xAs/GaAs Quantum Wells under the Influence of Temperature and Hydrostatic Pressure

Unveiling the influence of high hydrostatic pressure and protein interactions on the color and chemical stability of cyanidin-3-O-glucoside

This study explored how high hydrostatic pressure (HHP) and proteins (i.e., BSA and HSA) influence the color and chemical stability of cyanidin-3-O-glucoside (C3G) at neutral pH. HHP treatments (100–500 MPa, 0–20 min, 25 °C) did not affect C3G content in phosphate buffer (PB) and MOPS buffer. However, significant color loss of C3G occurred in PB due to pressure-induced pH reduction (e.g., from 7 to 4.8 at 500 MPa), which accelerated the hydration of C3G, converting it from colored to colorless species. Consequently, MOPS buffer was employed for subsequent stability experiments to assess the impact of protein and HHP on the thermal, storage, and UV light stability of C3G. Initially, rapid color loss occurred during heating and storage, primarily due to the reversible hydration of C3G until equilibrium with colorless species was reached, followed by slower parallel degradation. HSA increased the fraction of colored species at equilibrium but accelerated thermal degradation, while BSA had minimal effects. UV light irradiation accelerated the degradation of C3G colored species, causing direct degradation without conversion to colorless species, a process further intensified by the presence of proteins. HHP exhibited a negligible effect on C3G stability regardless of protein addition. These findings provide insights into anthocyanin stability under HHP and protein interactions, contributing to the development of future formulation and processing strategies for improved stability and broader applications.

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.

Monitoring And Controlling System Based on Internet of Things (IoT) for Ornamental Chrysanthemum Plants

Monitoring and controlling system based on Internet of Things has been developed for ornamental chrysanthemum plants. User interface of the system is a website application created using PHP programming language and MySQL as Database Management Systems. The IoT system built are the result of literature review of chrysanthemum plants, such as an ideal soil moisture for chrysanthemum plants is in the range of 40% to 60%, the average plant water requirement is 16.05 ml/day, it is also recommended to apply liquid fertilizer with a high N content of 2g per litre of water every week. This knowledge then applied in the IoT system. Research findings indicated that the device could be controlled through the website and was capable of transmitting real-time soil moisture data. This system not only triggers watering when the soil humidity falls below 41%RH and stops it when reaching 60%RH but also incorporates scheduled fertilizer according to predetermined schedules, meeting the anticipated outcomes. Water and fertilizer pumps produced volumetric flow rate that changed as the level of liquid in the storage tank decreases. The lower the height, the smaller the volumetric flow rate produced, this is due to the influence of hydrostatic pressure.

Band gap shifting of halide perovskite KSrCl3 from ultra-violet to visible region under pressure for photovoltaic applications

This research delves into the influence of hydrostatic pressure on the structural, electronic, and optical characteristics of the cubic halide perovskite KSrCl3. The reduction in interatomic distance caused by pressure has a considerable effect on the unit cell volume and lattice constant of this perovskite. As pressure increases, the electronic band gap closes, transferring from the ultraviolet to the visible spectrum. This phenomenon increases the efficiency of optoelectronic devices by simplifying the transition of electrons from the valence band to the conduction band. In addition, the material becomes more appropriate for use in a variety of optoelectronic applications when the band gap changes from indirect to direct at pressures of about 50 GPa. A comprehensive optical analysis suggests that KSrCl3 holds potential applications in surgical tools, integrated circuits, QLED, OLED, solar cells, waveguides, and materials designed for solar heat reduction. The tolerance factor “t" confirms the stability of the KSrCl3 phase across the applied pressure range, and the formation energy values with negative values show the attained thermodynamic stability.

Insight into the mechanism of high hydrostatic pressure effect on inhibitory efficiency of three natural inhibitors on polyphenol oxidase

The development of natural inhibitors of polyphenol oxidase (PPO) is crucial in the prevention of enzymatic browning in fresh foods. However, few studies have focused on the effect of subsequent sterilization on their inhibition efficiency. This study investigated the influence and mechanism of high hydrostatic pressure (HHP) on the inhibition of PPO by epigallocatechin gallate (EGCG), cyanidin-3-O-glucoside (C3G), and ferulic acid. Results showed that under the conditions of 550 MPa/30 min, the activity of EGCG-PPO decreased to 55.92%, C3G-PPO decreased to 81.80%, whereas the activity of FA-PPO remained stable. Spectroscopic experiments displayed that HHP intensified the secondary structure transformation and fluorescence quenching of PPO. Molecular dynamics simulations revealed that at 550 MPa, the surface interaction between PPO with EGCG or C3G increased, potentially leading to a reduction in their activity. In contrast, FA-PPO demonstrated conformational stability. This study can provide a reference for the future industrial application of natural inhibitors.

Hierarchical microstructure induced by hydrostatic pressure in a metastable β-Ti alloy

Hydrostatic pressure is a crucial tool to regulate the structure and properties of materials. However, the influence of hydrostatic pressure on the microstructure of metastable β-Ti alloys remains unclear. In this work, the microstructure and microhardness evolution of a metastable β-type Ti-30Zr-10Nb alloy under hydrostatic pressure (≤10 GPa) were investigated and compared with those under uniaxial pressure (≤1106 MPa). The results revealed that under hydrostatic pressure, Ti-30Zr-10Nb alloy formed a peculiar hierarchical microstructure composed of submicron-scaled α” plates with self-accommodating morphologies, nanoscale ω particles, and microscale shear bands containing nanoscale α” domains. The formation of a hierarchical microstructure effectively coordinates not only the isotropic macroscopic strains but also the local shear stresses under hydrostatic pressure. Compared to uniaxial pressure, the hydrostatic pressure facilitates the β to ω transformation, but hinders the β to α” transformation. The microhardness of the Ti3010 alloy reaches approximately 319 HV at a hydrostatic pressure of 10 GPa, which is 28 % higher than the highest microhardness obtained under uniaxial pressure. The current results highlight the promising potential of hydrostatic pressure in optimizing the mechanical properties of metastable β-Ti alloys.

Tunability of the nonlinear optical absorption in a GaAs/Ga0.7 Al0.3 As spherical quantum dots under external factors

We theoretically studied the linear, third-order nonlinear and total optical absorption coefficient changes of a typical GaAs/Al0.3Ga0.7As quantum dot system under the influence of hydrostatic pressure and temperature. The influence of hydrostatic pressure and temperature on the system is treated within the framework of effective mass. In this method, the relative changes of linear and nonlinear absorption coefficients are obtained by using density matrix method and iterative method. In addition, we also reveal the mechanism of the influence of hydrostatic pressure and temperature on the nonlinear optical properties, which is of great significance for us to better understand the causes. We have shown that hydrostatic pressure and temperature change the effective mass, resulting in significant changes in the linear and nonlinear optical properties of the system. In addition, we also reveal the mechanism of the influence of effective mass on the nonlinear optical properties, which is of great significance for us to better understand the causes.

Review of Underwater Anechoic Coating Technology Under Hydrostatic Pressure

AbstractThe underwater anechoic coating technology, which considers pressure resistance and low-frequency broadband sound absorption, has become a research hotspot in underwater acoustics and has received wide attention to address the increasingly advanced low-frequency sonar detection technology and adapt to the working environment of underwater vehicles in deep submergence. One the one hand, controlling low-frequency sound waves in water is more challenging than in air. On the other hand, in addition to initiating structural deformation, hydrostatic pressure also changes material parameters, both of which have a major effect on the sound absorption performance of the anechoic coating. Therefore, resolving the pressure resistance and acoustic performance of underwater acoustic coatings is difficult. Particularly, a bottleneck problem that must be addressed in this field is the acoustic structure design with low-frequency broadband sound absorption under high hydrostatic pressure. Based on the influence of hydrostatic pressure on underwater anechoic coatings, the research status of underwater acoustic structures under hydrostatic pressure from the aspects of sound absorption mechanisms, analysis methods, and structural designs is reviewed in this paper. Finally, the challenges and research trends encountered by underwater anechoic coating technology under hydrostatic pressure are summarized, providing a reference for the design and research of low-frequency broadband anechoic coating.

Effect of soaking solution and high hydrostatic pressure on in vitro digestibility of β-carotene in gluten free sweet potato noodles

Current work aimed to examine the influence of soaking solution (citric acid, calcium chloride and ascorbic acid) and high hydrostatic pressure (100, 200 and 400 MPa) on gelatinization properties of flour and antioxidant activity alongwith in vitro- digestibility of β-carotene in orange-fleshed sweet potato flour (OSPF) noodles. With the intensity of the HHP application, water absorption capacity increased linearly whereas water swelling capacity decreased in OSPF. Differential scanning calorimetry (DSC) of OSPF indicated a remarkable reduction in peak enthalpy due to gelatinization of starch and denaturation of protein. Hardness and cohesion of OSPF noodles at 400 MPa remarkably decreased whereas springiness increased. Antioxidant capacities of OSPF was gradually increased with the 400 MPa and ascorbic acid-treated OSPF due to the immense contribution of higher contents of TPC. After in vitro digestibility, noodles from OSPF prepared with 400 MPa treated flour exhibited maximum β-carotene retention. Thus, OSPF treated with 400 MPa might be potentially used for the production of noodles with acceptable texture and functional properties.

Pressure dependence of phase transformation, thermal expansion and barocaloric property in a polycrystalline Ni54Mn23Ga23 alloy

An experimental investigation was conducted to understand the influence of hydrostatic pressure on phase transition, thermal expansion and barocaloric property of a polycrystalline Ni54Mn23Ga23 alloy. Two pressure ranges of 0–1.28 GPa and 0–0.74 GPa were selected for thermal expansion and barocaloric property measurements due to the different test limits of instrumentals. The pressure dependence of fourteen parameters was studied systematically. It was found that the sample experiences a martensitic transformation (MT) near room temperature and the response of MT peak temperature (TM) to pressure is about 15.89 K/GPa. The phase transition strain (λtr), transformation width (ΔTtr) relative volume change (|ΔV/V|) and maximum adiabatic temperature change (ΔTad)max increase linearly with pressure and their shifting rates are about 0.071 %/GPa, 7.5 K/GPa, 0.211 %/GPa and 12.2 K/GPa, respectively. Simultaneously, applying hydrostatic pressure can also enhance the barocaloric property of the sample, leading to a large increase in the absolute value of the maximum entropy change (|ΔS|max), the refrigerating capacity (RC) and their reversible values. On cooling, the sensitivities of the reversible RC and its proportion to pressure are around 185.52 J/kg GPa and 16.7 %/GPa, respectively. Finally, the average linear expansion coefficient (αave) of both martensite and austenite phases keeps unchanged while in the MT region it decreases from -99.84×10–6/K to -86.04×10–6/K with increasing pressure from 0 to 1.28 GPa. These findings indicate that applying hydrostatic pressure can effectively adjust the phase transformation, thermal expansion and barocaloric property of Ni-Mn-Ga alloys, which are meaningful for their application in solid-state refrigeration.

High hydrostatic pressure stimulates microbial nitrate reduction in hadal trench sediments under oxic conditions

Hadal trenches are extreme environments situated over 6000 m below sea surface, where enormous hydrostatic pressure affects the biochemical cycling of elements. Recent studies have indicated that hadal trenches may represent a previously overlooked source of fixed nitrogen loss; however, the mechanisms and role of hydrostatic pressure in this process are still being debated. To this end, we investigate the effects of hydrostatic pressure (0.1 to 115 MPa) on the chemical profile, microbial community structure and functions of surface sediments from the Mariana Trench using a Deep Ocean Experimental Simulator supplied with nitrate and oxygen. We observe enhanced denitrification activity at high hydrostatic pressure under oxic conditions, while the anaerobic ammonium oxidation – a previously recognized dominant nitrogen loss pathway – is not detected. Additionally, we further confirm the simultaneous occurrence of nitrate reduction and aerobic respiration using a metatranscriptomic dataset from in situ RNA-fixed sediments in the Mariana Trench. Taken together, our findings demonstrate that hydrostatic pressure can influence microbial contributions to nitrogen cycling and that the hadal trenches are a potential nitrogen loss hotspot. Knowledge of the influence of hydrostatic pressure on anaerobic processes in oxygenated surface sediments can greatly broaden our understanding of element cycling in hadal trenches.

Measurements of the Permeability Coefficient of Waste Coal Ash under Hydrostatic Pressure to Identify the Feasibility of Its Use in Construction

The aim of this research was to measure the filtration properties of waste coal ash under the influence of hydrostatic pressure generated in a three-axial compression apparatus. The scope of work included determining the compactibility parameters, maximum bulk density and optimal moisture content. Permeability tests were performed for a sample with an average grain composition at three compaction indices IS: 0.964, 0.98 and 1.00. The hydrostatic pressure ranging from 0.5 to 1.8 bar corresponded to the layer depths from 2.17 to 7.83 m. Gradually increasing the pressure during the first loading cycle caused irreversible changes in the structure of the sample by local material agglomeration or grain interlocking. The water permeability coefficient was higher in the second loading cycle than in the first cycle. It was shown that waste coal ash cannot be used as a construction material on its own. To obtain constant filtration properties, the waste coal ash material should be doped, or an optimal compactionshould be used (IS = 1.00). The results presented in this study are important for assessing the use of waste coal ash for construction engineering purposes.

Investigation of the effect of high hydrostatic pressure on functional properties of pea protein isolate

The article presents the results of the influence of high hydrostatic pressure (HHP) on some functional properties of pea protein isolate. HHP was combined with different pH conditions to investigate the cumulative effect of HHP-based food processing conditions on the functional properties of pea protein isolate. Pea protein isolate solutions prepared at different pH conditions (5.0, 6.0, and 7.0) were subjected to HHP treatment at 200, 400, and 600 mPa at 18 °C for 5 min. The water resisting capacity (WRC), solubility and emulsifying properties of pea isolate samples were determined. It was found that treatment with NPP increased the VUS of pea protein isolates by 1.5 times. The greatest increase was observed in samples treated with a pressure of 400 mPa, at pH=7. An increase in solubility was found with an increase in pH from 6 to 7 when using a pressure of 400 and 600 mPa, however, for a sample of soybean isolate at pH 7 and a pressure of 200 mPa, on the contrary, a decrease in solubility was recorded. It has been shown that the effect of NPP on the emulsifying properties of pea protein depends on the processing conditions. In some cases, HPP can improve emulsifying properties, providing more stable emulsions. However, increasing exposure to high pressure up to 600 mPa leads to a decrease in emulsifying stability. The optimal parameters for using NPP for pea isolate proteins are a pH in the range of 6-7, and a pressure of 400 mPa.