Influence Of Hydrostatic Pressure Research Articles

Low‐pressure plasticization of PEBAX 2533 membrane by carbon dioxide

AbstractPEBAX 2533 membrane is used to investigate plasticization by carbon dioxide (CO2) at low pressure. To reduce complex interaction caused by hydrostatic pressure and competitive sorption, a new experimental technique named the “Rest test” is presented. In the Rest test, the membrane is exposed to permeation of CO2 at 4 bar for 30 min and then put to rest for up to 12 h with residual CO2 after ventilation. When the membrane rests more than 9 h with residual CO2 after the permeation, the permeability increases by, at least, 50%. Permeation of CO2 is the prerequisite condition of permeability increase during the rest. Permeability increase in the Rest test is improved by permeate side purge and prolonged rest period. Fugacity and sorption of leftover CO2 during the rest are the main factors inducing the permeability increase, whereas the permeability increase is suppressed by higher feed pressure and longer CO2 permeation time, indicating the influence of hydrostatic pressure. The Rest test cannot increase the permeability of glassier PEBAX 1657. The findings and relevant factors suggest that low‐pressure plasticization during the rest is a potential source of the permeability increase.

The Influence of Static Pressure on Bubble Size and Contact Angle of Quartz: Mimicking What May Happen Inside a Hypothetical Flotation Column

This paper addresses the influence of hydrostatic pressure (Phyd) on bubble diameter (db) and contact angle (θ) of quartz in pure water versus collector solution (Flotigam® EDA, γLG = 57 mN/m) at 20 °C. The pressure range (0–300 kPa) applied against the bubbles’ walls mimics what may happen along the vertical axis of a hypothetical flotation column (HFC) that processes iron ore slurry via cationic reverse flotation of quartz. From the column’s bottom (Phyd≈ 300 kPa) to its top (Phyd≈ 0 kPa), a continuous relief of Phyd occurs steadily. Results indicate that a decrease of Phyd promotes a decrease of θ from 47° to 16° in pure water and from 61° to 42° in the presence of collector. Likewise, db increases approximately 60% from the column’s bottom to its top and, consequently promoting an increase in bubble ascending velocity (vb). Values of vb and db were used to assess the bubble Eötvos number (Eo) and the Weber number (We) aiming at characterizing bubble hydrodynamics. It was found that inertial forces dominate surface forces (We > 1) as db> 1.86 mm. This dominance constitutes a preliminary indication of a greater likelihood of coarse particles (diameter > 100 μm) detaching from bubbles. This situation is typically found in the upper parts of the HFC addressed in this paper.

Third Harmonic Generation in Al0.3Ga0.7As/GaAs Quantum Dots: the Influence of the Structure Parameter, Static Electric, and Magnetic Field

Herein, the nonlinear third harmonic generation (THG) distribution of Al0.3Ga0.7 As/GaAs quantum dots is studied under the combined influence of hydrostatic pressure and structural parameters, considering the presence of an electrostatic field and magnetic field. Hydrostatic pressure is introduced into the system as an environmental condition in the form of effective mass. When the hydrostatic pressure changes within a certain range, the peak shift and resonance peak of the THG coefficient change significantly, reflecting its application effect elegantly. Interestingly, the effects of these application modes on nonlinear optical properties have different effects, whether it is hydrostatic pressure, structural parameters, or electromagnetic fields.

Discussion on the zero-calibration and the zero line in the measurement of central venous pressure and invasive arterial blood pressure

To figure out the timing of zeroing and the location of the zero line in the central venous pressure (CVP) monitoring and invasive arterial blood pressure (IBP) monitoring, and to provide scientific and accurate data for patients management. The liquid vessel models were used to simulate the pressure measurement process of the continuous pressure monitoring system. Based on the theory of fluid mechanics and the knowledge of blood pressure physiology and cardiovascular anatomy, the composition and influencing factors of the pressure in the fluid-filled catheter system during the zeroing and placing the transducer in the zero line of CVP and IBP, were analyzed. The pressure in the liquid-filled catheter system was composed of atmospheric pressure, the pressure of pumping bag, the gravity of the water column (the vertical distance between the liquid level of Murphy's dropper and pressure transducer, ΔH), and the resistance of tube wall. This pressure value is set as a pressure of 0 mmHg (1 mmHg ≈ 0.133 kPa). In the process of pressure measurement, when the pressure transducer was placed at a horizontal position of 10 cm below the highest liquid level of the vessel, the pressure measured at different catheter tip positions was all 10 cmH2O (1 cmH2O ≈ 0.098 kPa); When the pressure transducer was placed at the horizontal position of the highest liquid level of the vessel, the measured pressure is 0 mmHg. Zeroing should repeatedly be performed only when one or more conditions (atmospheric pressure, pressure of pumping bag, gravity of ΔH water column and resistance of tube wall) are changed. In the measurement process, the pressure transducer should be placed at the zero line position at any time to eliminate the influence of hydrostatic pressure and to ensure the objective and accurate value.

Influence of high hydrostatic pressure on protein clustering: Implications for processing and macroscopic crystallization.

High pressure (HP) is used in various industrial applications to sterilize a product stream or to confer desired properties. HP is also present during freezing processes, yet relatively little is known about its effects on protein phases. Protein clustering has been well-documented as a precursor to liquid-liquid phase separation (LLPS) and macroscopic crystallization. Several globular proteins have been previously shown to salt-out in the presence of ammonium sulfate, with clustering observed when approaching a first aggregation boundary, phase separation beyond a second aggregation boundary, and gel bead nucleation between them. Nanocrystalline structures have been observed within the salted-out macroscopic gels, suggesting clusters below the first aggregation boundary are precursors to macroscopic crystals. The present work examines the influence of pressures up to 400 MPa on salt-induced clustering in ovalbumin solutions on either side of the first aggregation boundary. Small-angle x-ray scattering (SAXS) on aged solutions approaching the boundary reveals the presence of protein clusters, and a computational deconvolution into fractional oligomer population contributions to scattering was used to assess salt-induced clustering with similar characteristics on either side of the first aggregation boundary. Surprisingly, HP-SAXS on fresh samples reveals a sharp shift in pressure effects on clustering across the boundary. The discrepancy in pressure response suggests a fundamental difference in the clustering mechanism across the first aggregation boundary, and that clusters in this region are early nucleated gels rather than crystal precursors. The current results are of interest to protein processing and LLPS, providing insights into competing mechanisms of protein aggregation and suggesting pressure-dictated clustering as a potential tool for controlling macroscopic phase behavior.

High hydrostatic pressure influence on the properties and tendency to agglomeration of ZrO2 grains of the Al2O3 – YSZ composite ceramics system

The results of studying the influence of high hydrostatic pressure (HHP) on the structure formation and properties of composite ceramics of the Al2O3-ZrO2 + 3mol% Y2O3 (YSZ) system, based on the metastable Al2O3 phase, are presented in this work. The phase composition of the powders, the structure, physical and mechanical properties of the Al2O3 - YSZ ceramics were studied taking into account the YSZ concentration and the pressing pressure. We have found that various crystallization processes occur during the sintering of ceramics and two types of structure are realized: aggregate-hardened and disperse-hardened, depending on the HHP value. It is shown that the processing of compacts under HHP conditions at 600–700 MPa prevents the formation of agglomerates of YSZ grains in the intergranular space of Al2O3, and the maximum values of physical and mechanical characteristics are achieved at concentrations of 10 and 15% YSZ and HHP values of 700 MPa.

Finite Element Implementation of the Exponential Drucker–Prager Plasticity Model for Adhesive Joints

This paper deals with the numerical implementation of the exponential Drucker-Parger plasticity model in the commercial finite element software, ABAQUS, via user subroutine UMAT for adhesive joint simulations. The influence of hydrostatic pressure on adhesive strength was investigated by a modified Arcan fixture designed particularly to induce a different state of hydrostatic pressure within an adhesive layer. The developed user subroutine UMAT, which utilizes an associated plastic flow during a plastic deformation, can provide a good agreement between the simulations and the experimental data. Better numerical stability at highly positive hydrostatic pressure loads for a very high order of exponential function can also be achieved compared to when a non-associated flow is used.

ВЛИЯНИЕ ГИДРОСТАТИЧЕСКОГО ДАВЛЕНИЯ НА ИЗМЕНЕНИЕ СТЕПЕНИ МИНЕРАЛИЗАЦИИ ПОДЗЕМНЫХ ВОД

The article discusses a study on the identification of physical phenomena of desalination and squeezing of underground mineralized waters under the influence of hydrostatic and osmotic pressure? As well as the appearance of a hydroosmotic barrier between less and highly mineralized waters as a result of reaching an equilibrium state between hydrostatic and osmotic pressure.

A new trigonometric shear deformation theory for free vibration of graphene reinforced metal–matrix nanocomposite plate submerged in fluid medium

A novel trigonometric shear deformation plate theory (TSDPT) is proposed for the vibrational characteristics of the functionally graded graphene-reinforced metal matrix nanocomposite (FG-GRMMNC) plate immersed in the fluid medium. Combining trigonometric and inverse trigonometric functions, a new shape function is presented to determine the distribution of the transverse shear strains and stresses without using any transverse shear correction factors. Using a combination of the Halpin–Tsai micromechanical model and the rule of mixtures, the properties of three distributions of GRMMNC are investigated. Aluminum serves as the matrix material, and graphene nanoplatelets are utilized as the reinforcing material. Due to the ideal and incompressible fluid medium, the influence of hydrostatic pressures and free surface waves on structures is disregarded. The governing equations are derived using the Hamilton’s principle, taking into account the influences of three plate–fluid interaction models. The Galerkin’s method is then utilized to determine the natural frequencies of the FG-GRMMNC plate with simply supported boundary conditions. To confirm the validity of the proposed theory, the obtained outcomes are compared with those found in the published works. On the vibrational characteristics of the nanocomposite plate, influences of material properties, distribution patterns, geometrical parameters, and fluid environments are also investigated in depth.

Influence of High Hydrostatic Pressure and Pulsed Electric Field Treatment on Moisture Absorption of Wheat Grains

AbstractThe effect of high pressure (0.1–600 MPa) and pulsed electric field (E = 3 and 6 kV cm−1) pretreatments on the moisture absorption properties of non‐hulled wheat grains were investigated. Microwave sensor was used as a non‐invasive technique for determination of the moisture content. The results demonstrated that high pressure soaking (>100 MPa) of wheat grains significantly increased the water uptake. High pressure soaking (600 MPa) decreased the water uptake due to the starch gelatinization and as a result appearance of structural changes. Compared to control samples, PEF‐pretreated samples showed a sharp increase of water absorption at the initial process with a further reduction of equilibrium water content. Peleg's water absorption model was adapted to the measured data of non‐hulled wheat grains. Results showed a good prediction of Peleg's equation in all experiments, which gave the possibility for estimation of initial water absorption rate and equilibrium moisture content.

Influence of hydrostatic pressure on the corrosion and discharging behavior of Al-Zn-In-Mg-Ti alloy

The corrosion and discharging behavior of Al-Zn-In-Mg-Ti alloy were studied at a series pressures ranged from 0.1 MPa to 13.0 MPa using weigh loss experiments, electrochemical techniques, and imaging measurements et al. Results reveal that the self-corrosion and self-discharging process of Al-Zn-In-Mg-Ti alloy live through the same three stages, which are all accelerated by hydrostatic pressure. The discharging performance of Al-Zn-In-Mg-Ti drops with increasing pressure, which is caused by the acceleration of cathodic process and severer intergranular corrosion. The corresponding cathodic protection design based on Al-Zn-In-Mg-Ti sacrificial anode with the changing pressure has been set up, which follows exponential function.

Three-Parameter Twin τ2 Strength Theory for Brittle Materials under Multiaxial Stress State and Its Application

The strength failure of brittle materials under complex stress is an important problem. Herein, we propose a novel three-parameter twin τ2 strength theory considering the influence of hydrostatic pressure and normal stress on the principal shear-stress surface, derive a mathematical expression for the strength theory, and compare the theoretical predictions under several stress states with existing experimental data. The results show that different ultimate stress ratios, α and β, correspond to different strength theories for brittle materials. The principal stress σ1 increases gradually with an increase in σ2 (=σ3) under the stress state σ1 > σ2 = σ3; σ1 (=σ2) increases gradually with an increase in σ3 under the stress state σ1 = σ2 > σ3. Furthermore, the biaxial compressive strength is considerably higher than the uniaxial compressive strength under the biaxial compressive stress for σ1 > 0, σ2 > 0, and σ3 = 0. When σ3 is fixed and σ2 is relatively small under the stress states of σ1 > 0, σ2 > 0, and σ3 > 0, the maximum principal stress σ1 increases with the increasing σ2. When σ2 is relatively large and as σ1 gradually decreases with the increasing σ2, the effect law of intermediate principal stress σ2 is obtained.

Influence of High Hydrostatic Pressure (HHP) on the Ordered Structure and on the Functional, Morphological, and Thermal Properties of Japonica Rice Starch

AbstractHigh Hydrostatic Pressure (HHP) offers a new way of gelatinizing starch, preserving its sensory characteristics such as color and flavor, minimizing thermal damage, in addition to being a technique aims at the production of food thickeners. The aim of the study is to evaluate the influence of HHP on the ordered structure and on the functional, morphological, and thermal properties of japonica rice starch (JRS). JRS is dispersed in 20% water and then HHP is applied at pressures of 200, 400, and 600 MPa min−1, where structural, functional, morphological, and thermal parameters are evaluated after the non‐thermal modification. Cracks are found on the surface, with an increase in the average diameter in relation to the pressure applied to the starch, as well as a loss of crystallinity and molecular order, mainly for 600MPa min−1. The modified starch shows a greater affinity for water and oil than the native starch (NJS), and for milk absorption, it is found that the binding capacity to whole milk is higher. HHP is an efficient, low‐cost method and which aims to reduce the use of toxic reagents to the environment.

Bioaccessibility of Betalains in Beetroot (Beta vulgaris L.) Juice under Different High-Pressure Techniques.

The influence of high hydrostatic pressure (HHP) and supercritical carbon dioxide (SCCD) on the bioaccessibility of betalains in beetroot (Beta vulgaris L.) juice was investigated. Freshly squeezed juice (FJ) was treated at a mild temperature of 45 °C for 10 min (T45), pasteurization at 85 °C for 10 min (T85), HHP at 200, 400, and 500 MPa at 20 °C for 5 min (HHP200, HHP400, HHP500) and SCCD at 10, 30 and 60 MPa at 45 °C for 10 min (SCCD10, SCCD30, SCCD60). The juice was subjected to an in vitro digestion system equipped with dialysis. The content of betalains was measured with the aid of a High-Performance Liquid Chromatography (HPLC), the antioxidant capacity (AC) (ABTS•+, DPPH•) was analyzed during each digestion step, and the bioaccessibility of betacyanins and betaxanthins was assessed. The SCCD at 30 and 60 MPa significantly increased pigments’ bioaccessibility compared with other samples. The 30 MPa proved particularly advantageous, as it increased the bioaccessibility of the total betacyanins and the betaxanthins by 58% and 64%, respectively, compared to the T85 samples. Additionally, higher bioaccessibility of betacyanins was noted in HHP200 and HHP400, by 35% and 32%, respectively, compared to FJ, T45, and T85 samples. AC measured by ABTS•+ and DPPH• assays were not unequivocal. However, both assays showed significantly higher AC in SCCD60 compared to T85 (21% and 31%, respectively). This research contributed to the extended use of the HHP and/or SCCD to design food with higher health-promoting potentials.

Calculating the time within which the emulsion explosive sensitized by gas microbubbles preserves the susceptibility to the initiating pulse

Introduction. The paper considers the behaviour of the sensitizer, gas microbubbles (GMB). The matters of emulsion explosives (EE) reliable detonation in the course of blasting are addressed. Research objective. To improve the reliability of blasting operations that apply EE, the research aims to develop the procedure calculating the time within which a borehole descending charge of EE, sensitized by GMB preserves the ability to initiate. Methods of research are based on analytical research describing GMB deformation under the impact of hydrostatic pressure of the charge column as well as further motion of GMB in the pseudoplastic liquid. Results. It is known that with the sensitization of EE, GMB, with a decrease in total porosity below a certain critical value, EE lose the ability to initiate. In descending blast wells, under the influence of excessive hydrostatic pressure of the charge column, the size of the GMB decreases and the overall porosity of the EE decreases due to the compression of these microbubbles, which negatively affects the detonation capabilities of the EE. In this case, as shown in the article, after the formation of the borehole charge, an additional, slowly progressive decrease in the porosity of the EE occurs due to the ascent of the GMB. This contributes, after a certain period of time, to the loss of the ability to detonation decomposition by the downhole charge of the EE, which must be taken into account when the charge is in an explosive well for a long time. An analytical solution has been obtained that makes it possible to estimate the time of preservation by a borehole descending charge of EE, sensitized by GMB, the ability to initiate. The solution takes into account the heterogeneity of the GMB in size and the power of the intermediate detonator used to initiate the EE charge. Conclusions. The regularities obtained in the article make it possible to increase the reliability of blasting operations using EE, sensitized GMB.

Impact of temperature and pressure on phase separation in the basal plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals

Here, we study the impact of high hydrostatic pressure (up to 11 kbar) on the conductivity in the basal ab plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals. Conversely to YBa2Cu3O7–δ single crystals, it was found that high pressure leads to phase separation in the basal plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals. The mechanisms of the influence of praseodymium and high hydrostatic pressure on the two-step resistive transition to the superconducting state are discussed.

Influence of temperature and hydrostatic pressure on the nonlinear optical properties in a GaAs/GaAlAs Kratzer-Fues confined quantum well

The investigation of the comprehensive influence of temperature and hydrostatic pressure on the nonlinear optical absorption coefficients(OACs), optical rectification(OR), second harmonic generation(SHG) and third harmonic generation(THG) in a Kratzer-Fues confined quantum well(QW) is carried out by means of the effective-mass approximation and density matrix formalism. The findings indicate that the nonlinear optical properties(OACs, OR, SHG, THG) are significantly different in response to temperature and hydrostatic pressure. Simultaneously, we find that the effects of temperature and hydrostatic pressure on the nonlinear OACs, OR, SHG and THG in this system are more pronounced. So the magnitude and the red and blue shift in the position of the OACs, OR, SHG and THG can be adjusted by changing the strength of the temperature and hydrostatic pressure, thus promoting the development of the optical modulators and miscellaneous device applications based on the nonlinear properties. • The OACs, OR, SHG and THG in Kratzer-Fues QW are studied. • We obtain the energy eigenvalues and eigenfunctions via the fine difference method. • The effect of P and T on these important optical quantity are also studied. • Nanostructures possess considerably different behaviors under P and T.

Influence of high hydrostatic pressure ( HHP ) pretreatment on plum ( Prunus salicina ) drying: Drying approach, physical, and morpho‐structural properties of the powder and total phenolic compounds

Influence of high hydrostatic pressure ( <scp>HHP</scp> ) pretreatment on plum ( <i>Prunus salicina</i> ) drying: Drying approach, physical, and morpho‐structural properties of the powder and total phenolic compounds

Effect of hydrostatic pressure on the thermodynamic and kinetic behavior of metal electrode reactions

Based on the thermodynamic and dynamic theory of physical chemistry, focusing on the problem that hydrostatic pressure affects metal corrosion reaction in deep-sea environment, this paper analyzes the influence of hydrostatic pressure on partial molar volumes and activities of metals and components in deep-sea environment, deduces the relationship between hydrostatic pressure and equilibrium potential and exchange current density of different electrode reactions, and establishes a metal corrosion model under hydrostatic pressure. The results show that under the condition of ignoring the temperature change, hydrostatic pressure can change the partial molar volume and activity of metal and environmental components, and then affect the equilibrium potential and exchange current density of each electrode reaction in the corrosion process. With the increase of hydrostatic pressure, the equilibrium potential of anodic dissolution reaction of Fe, Al and Zn decreases, and the exchange current density decreases. Furthermore, it increases the equilibrium potential and decreases the exchange current density of cathodic reduction of dissolved oxygen, while it decreases equilibrium potential and increases the exchange current density of cathode hydrogen evolution reaction. Correspondingly, the corrosion potential and corrosion current density of different corrosion cells also change under the effect of hydrostatic pressure. In addition, hydrostatic pressure will amplify the activity difference of different phases in metal, which will correspondingly lead to the increase of the difference of electrode reaction equilibrium potential and exchange current density of different phases in metal, and then affect the micro galvanic corrosion between different phases.

Trapping Hydrogen Atoms in Vacancies of Li2TiO3 Crystal: A First-Principles Study.

The hydrogen atom capacity in the vacancies of the Li2TiO3 crystal is systematically studied by the first-principles method to evaluate its tritium release performance as a solid breeder material in nuclear fusion reactors. The adsorption process of adding hydrogen atoms one by one in the vacancy are investigated to find the possible adsorption sites of the hydrogen atoms in the vacancy. The charge transfer and density of states analysis are performed to reveal the form of a hydrogen–hydrogen dimer in the vacancy. Also, the trapping energy and formation energy are defined and calculated to determine the hydrogen atom capacity of the system. According to the simulations, the Ti vacancies have the strongest hydrogen atom capacity followed by Li vacancies, and O vacancies are the weakest. The influence of hydrostatic pressure on the hydrogen atom capacity is also investigated. Our results reveal the hydrogen capacity of vacancies in the Li2TiO3 crystal from the atomic scale, which also provide a theoretical guide to the related tritium release experiments.