ABSTRACT We present the in situ neutron diffraction data of a water and silica mixture at high pressure and temperature. We show initially the formation of ice VI at 1.5 GPa at 290 K in the presence of crystalline SiO 2 , upon heating we observe its melting at ∼400 K. Upon further warming to 1200 K, we observe melting of the crystalline silica. Upon cooling to 290 K and recovery to ambient pressure

ABSTRACT Melting of orthorhombic boron silicide B6Si has been studied at pressures up to 8 GPa using in situ electrical resistivity measurements and quenching. It has been found that in the 2.6–7.7 GPa range B6Si melts congruently, and the melting curve exhibits negative slope of −31(2) K/GPa that points to a higher density of the melt as compared to the solid phase. At very high temperatures B6Si

ABSTRACT Among the non-thermal food technologies, high pressure processing (HPP) is currently the most widespread intervention in the juice industry. The study herein was conducted to challenge a wide range of pressure (401–599 MPa) and dwell time (87–313 s) in orange juice processing. The parameters were combined and targeted a minimum of 5-log cycle reductions in a cocktail for the pathogens of reference

ABSTRACT 3.65 Å-phase (or hydroxide-perovskite), MgSi(OH)6, is a representative of dense hydrous magnesium silicates (DHMS) with maximum water content (up to ∼35 wt.% H2O) and thus is of interest as one of the largest repositories of water among all the known hydrous phases. Sample of 3.65 Å-phase, grown in DIA-type multianvil apparatus, was studied by Raman spectroscopy under pressure up to ∼7 GPa

ABSTRACT Characterization of a new pressure medium Daphne Oil 7575 using a set of three manganin coils, a superconducting temperature of lead and the response of two perpendicular strain-gages down to low temperatures is presented. A complementary study of Daphne Oil 7474 and Daphne Oil 7373 employing identical methods is included as well. Temperature dependence of the solidification point of Daphne

By means of comparing molar volumes at reference ambient conditions (298 K, 1.105 Pa) of 160 pressure-driven polymorphic transitions in chalcogenides, germanates, silicates, simple molecular compounds, elemental non-metals and a few metals it is shown that for reconstructive transitions between 0.1 and 150 GPa, mean volume contraction ranges around 11% for about 85% of all examined materials. The mean

At the 26th AIRAPT conference in 2017, a task group was formed to work on an International Practical Pressure Scale (IPPS). This report summarizes the activities of the task group toward an IPPS ruby gauge. We have selected three different approaches to establishing the relation between pressure (P) and ruby R1-line shift (Δλ) with three groups of optimal reference materials for applying these approaches

ABSTRACT To understand the practical effects of pressure-transmitting media (PTM) on neutron diffraction using Paris–Edinburgh presses, diffraction patterns of MgO were collected to approximately 20 GPa using PTMs of Pb, AgCl, 4:1 methanol–ethanol (ME) mixture with and without heating, N2, and Ar. Hydrostaticity in the sample chamber estimated from the MgO 220 peak width improves in the order of Pb

We tested boron-doped diamond (BDD) synthesized by chemical vapor deposition (CVD) as a heating element in a multi-anvil apparatus. We succeeded in manufacturing BDD into a tubular shape by laser cutting and electric discharging machining. The BDD tube shaped by the electric discharging machining was contaminated by discharging electrode materials (Mo and W), which affected the heating performance

High temperature is of paramount importance in high pressure science. One of the leading tools in this respect is the resistively heated diamond anvil cell (DAC), where the heat is provided by small heaters, positioned close to the diamond/gasket/sample region (internally heated DAC, IHDAC) or by wrapping the DAC body into bigger heaters (externally heated DAC, EHDAC). Although IHDACs can reach sample

The phase transitions and equation of state measurements were carried out on rare earth metal Holmium (Ho) to 282 GPa using toroidal diamond anvils thereby doubling the pressure range to which it has been studied previously. The first set of experiment employed standard beveled diamond anvils utilizing copper as an x-ray pressure standard to 217 GPa. The second set of experiment employed toroidal diamond

The compressibility and effect of pressure on the vibrations of merrillite, Ca9NaMg(PO4)7, were studied by using diamond anvil cell at room temperature combined with in-situ synchrotron X-ray diffraction and Raman spectroscopy up to about 18 and 15 GPa, respectively. The pressure-volume data was fitted by a third-order Birch–Murnaghan equation of state to determine the isothermal bulk modulus as K0

High pressure processing (HPP) and sous vide may increase the shelf-life of high value seafood products without the use of additives. This study investigated the effects of 150MPa or 350MPa for 10min on microbial, sensory, and physicochemical qualities of raw and subsequently sous vide cooked (65°C) lobster tails during 28 days of refrigerated storage. Raw lobster pressurized at 350MPa or sous vide

Elastic stiffness constants, C ijs, of single crystal of NaCl B1 phase have been determined at pressure up to 20 GPa using inelastic x-ray scattering to measure elastic wave velocities and x-ray diffraction to measure densities in the same experimental setup. The Voigt-Reuss-Hill average velocities calculated from the present Cijs are in good agreement with previous ultrasonic measurements of polycrystalline

ABSTRACT A new method for stirring under high pressure conditions has been developed and tested. The key component is a Teflon cell assembly equipped with magnetic stirring function, which is capable to operate across a wide pressure range, up to at least 2 GPa, in a large volume press. The setup enables adjustable stirrer rotation rate and detection of stirring in a sample, e.g. to observe liquid–solid

The quasi-hydrostatic compression of cesium chloride and cesium bromide has been measured with X-ray diffraction up to 141 GPa at 300 K. A cubic to orthorhombic P m 3 ¯ m → P m m a transition, with a ≥10% distortion of lattice parameters, is evidenced in CsBr around 60 GPa. A smaller distortion (∼1.5%) appears in CsCl at the same pressure, followed by a likely transition to a lower symmetry phase which

Quantitative single crystal neutron-diffraction in diamond anvil cells has so far been limited by the neutron flux available at the various neutron sources. As a result, highly precise measurements of the exact position of light elements have not been possible preventing, for example, structural studies of hydrogen and hydrogen bonds under pressure. Here we report experiments carried out on SNAP at

We report experimental determination of compressibility and thermoelasticity for CrN based on in situ high pressure/high temperature synchrotron x-ray diffraction measurements. The pressure-induced cubic-to-orthorhombic phase transition is observed at ∼ 5 GPa in high-quality CrN samples synthesized using a high pressure reaction route. Equation of state, bulk modulus and axial compressibility of this

A systematic study of orthorhombic phase formation at ambient conditions beyond a critical concentration of dopant Tantalum (Ta) in HfO 2 is reported. The effect on the path of structural evolution due to Ta doping in HfO 2 was also investigated. Studies on Ta-doped HfO 2 samples and their path of structural evolution under compression have significant implications for materials undergoing β-decay

Thermal conductivities of planetary materials under extreme conditions are important input parameters for modeling planetary dynamics such as accretion, geodynamo and magnetic field evolution, plate tectonics, volcanism-related processes etc. However, direct experimental measurements of thermal conductivity at extreme conditions remain challenging and controversial. Here we propose a new technique

The crystal structures, lattice dynamics, mechanical, electronic properties, and electron–phonon coupling of Th3N4 under environmental conditions and high pressures have been studied by merging first-principles calculations and particle-swarm optimization algorithm. Four structures are identified for Th3N4, including the R3¯m, I4¯3d, R3¯, and C2/m phases, in which the I4¯3d, R3¯, and C2/m phases are

The pressure stability of the first hydration shell of Y 3+ ions in aqueous solution has been investigated by means of extended x-ray absorption fine-structure spectroscopy at the yttrium K-edge for hydrostatic pressures up to 4.5 kbar and concentrations between 1 M and 2.5 M. We find approximately 8.4 water molecules surrounding the yttrium cation at a mean distance of 2.370 Å at ambient conditions

A new high pressure cell for neutron diffraction experiments using nano-polycrystalline anvils is presented. The cell design, off-line pressure generation tests and a gas-loading procedure for this cell are described. The performance is illustrated by powder neutron diffraction patterns of ice VII to ∼82 GPa. We also demonstrate the feasibility of single crystal neutron diffraction experiments of Fe3O4

A new opposed type double-stage large volume cell has been developed to compress large volume samples to more than 100 GPa (Mbar) pressure. A pair of second-stage diamond anvils is introduced into the first-stage Paris–Edinburgh press. The double-stage large volume cell allows the generation of ultrahigh pressures using a large culet diameter of the second-stage diamond anvils (diameters of 0.5–1.2 mm)

Here we report a novel route for synthesizing nano-polycrystalline diamond (NPD) using stearic acid (C18H36O2) as a starting material under high pressure and high temperature. The obtained NPD shows a transparent dark-yellowish color similar to the standard NPD synthesized from graphite and consists of extremely fine diamond grains (∼10 nm). The temperature required for the present synthesis of pure

Current anvil designs and problems associated with various efforts to generate static high pressures beyond the limit of conventional diamond anvil cells (DACs) (∼400 GPa) are reviewed. Pressures of up to 1 TPa have been reported by one research group using the double-stage DAC (ds-DAC) technique, but no other research group has successfully reproduced this high pressure result. Some research groups

Deep-ultraviolet continuous-wave photoluminescence spectroscopy is performed for nano-polycrystalline diamond (NPD) synthesized by a high pressure high-temperature technique. NPD exhibits clear deep-ultraviolet emissions, which originate from intrinsic excitonic transitions assisted by a momentum-conserving phonon with a photon. Surprisingly, the peak emission energy is about 30 meV higher than that

We present the element-selective local structure analysis of ferromagnetic Fe 65Ni 35 Invar alloy and Fe 72Pt 28 alloy under high pressures as a recent application of nano-polycrystalline diamond (NPD) to extended X-ray absorption fine structure (EXAFS). The Invar effect is a phenomenon where thermal expansion becomes nearly zero in a wide range of temperatures. Fe 72Pt 28 is an alloy exhibiting negative

We present the first application of double-stage diamond anvil cells (ds-DACs) to X-ray absorption spectroscopy (XAS) of Rhenium (Re) metal. By using highly stable and sub-micron sized X-ray beam, XAS spectra were successfully observed at the L2,3-edges from the sample encapsulated in the small space between the second-stage anvils. The pressure generation exceeding 300 GPa was evaluated by the pressure-induced

We investigated the optical properties (absorption, luminescence and Raman spectra) of nanopolycrystalline diamond (NPD) aiming at exploring its capabilities as a pressure sensor and as a pressure-cell anvil for combined X-ray/neutron and optical studies. Notably, we analysed the Raman peak shift and broadening with pressure using a Moissanite Anvil Cell (MAC). The results are compared with those obtained

Nano-polycrystalline diamond (NPD) with various grain sizes has been synthesized from glassy carbon at pressures 15–25 GPa and temperatures 1700–2300°C using multianvil apparatus. The minimum temperature for the synthesis of pure NPD, below which a small amount of compressed graphite was formed, significantly increased with pressure from ∼1700°C at 15 GPa to ∼1900°C at 25 GPa. The NPD having grain

A high-pressure cell for in-situ single-crystal neutron diffraction was developed. The cell uses nano-polycrystalline diamond anvils in a tubular load frame made of bulk metallic glass which is highly transparent to neutrons and does not produce Bragg reflections. Diffraction peaks from a sample can be measured from almost any direction and the simple geometry of the cell allows accurate attenuation

High pressure energy-dispersive X-ray absorption spectroscopy is a valuable structural technique, especially, when combined with a nano-polycrystalline diamond anvil cell. Here we present recent results obtained using the dispersive setup of the ODE beamline at SOLEIL synchrotron. The effect of pressure and temperature on the X-ray induced photoreduction is discussed on the example of nanocrystalline

Nano-polycrystalline diamonds (NPDs) have become fundamental tools for cutting-edge X-ray absorption spectroscopy (XAS) studies at high P/T conditions that opened up new research directions by overcoming previous limitations. Indeed, NPDs yield a continuous and weak X-ray background signal which enables the collection of high-quality XAS data of materials compressed in diamond anvil cells. This is

In this work, we use extended X-ray absorption fine structure (EXAFS) data collected using nano-polycrystalline diamond anvil cell to study the atomic arrangement in Zr–Cu metallic glass in high pressure (HP) conditions. To reveal the microscopic details of stress accommodation mechanism, we performed molecular dynamics (MD) simulations of the HP atomic arrangement. By comparing the experimental and

The use of nanopolycrystalline diamond has allowed a systematic study on deformation of polycrystalline diamond composites (PCDCs). Bulk PCDCs samples containing either Co or SiC as a binding agent were deformed under high pressure and temperature to strains up to 18% at strain rates ∼10−5 s−1. All samples exhibit strong work hardening. The strength of PCDCs depends on the amount and type of binding

Data-driven exploration for pressure-induced superconductors was performed based on the high-throughput first-principles screening of electronic band structures. In the screening conditions, we focused on the characteristics including a narrow band gap, flat band feature, and possibility of metallization under high pressure. The 27 promising compounds were screened out from the database of Atomwork

Both micro-paired and conical support type double-stage diamond anvil cells (ds-DAC) were tested using a newly synthesized ultra-fine nano-polycrystalline diamond (NPD). Well-focused X-ray sub-micron beam and the conically supported 2nd stage anvils (micro-anvils) with 10 μm culet enable us to obtain good quality X-ray diffraction peaks from the sample at around 400 GPa. The relationship between confining

Generation of high pressure is a key to the investigation of the interior of the Earth. The Kawai-type multianvil apparatus (KMA) has been widely used in the fields of Earth science and material science. In conventional KMA, tungsten carbide (WC) has been used as the second stage anvil material. However, attainable pressure is limited to ∼70 GPa even if newly developed WC is used. Recently, on the

(2020). A brief history of nano-polycrystalline diamond. High Pressure Research: Vol. 40, Nano-Polycrystalline Diamond: Synthesis and applications, pp. 1-2.

Obtaining both high hardness and toughness is a challenge in B4C-nano-adhesive composites. Solving the inhomogeneous distribution of nano-adhesives in B4C and forming the chemical bonding at grain boundary is an effective method. Here, we reported that the uniform distribution of titanium diboride (TiB2)-reinforced B4C composites synthesized by high-pressure and high temperature (HPHT). It is found

TiC-MgO composite was developed as a heating element for X-ray study in the multi-anvil high pressure apparatus. We synthesized TiC-MgO blocks (50–70 wt.% of TiC) by compression in a cold isostatic press followed by baking in a gas flow furnace. Heaters of tubular shape were manufactured from the synthesized blocks either by lathe or numerically controlled milling machine. The so-produced heating elements

An isentropic equation of state (Isen-Eos) in a high-density polyethylene (HDPE) consists of four variables of PS, VS, TS and entropy S where the VS, PS and TS are variables satisfying the isentropic condition that S is constant. The typical values of isentropic derivatives at constant S = 21.35 [J/molK] and T = 313.15 [K] are αS = −1.66 × 10−3 [K−1] and γS = 13.8 [10−3 GPa] where αS and γS are isentropic

Based on the first-principles calculations within the density functional theory and crystal structure prediction algorithms iron phosphide phases stable under pressure of the Earth’s core and temperatures up to 4000 K were determined. A new low-temperature modification FeP-P21/c stable above ∼75 GPa was predicted. Fe2P with the allabogdanite structure has been established to be stable in the low-temperature

This study was to investigate the piezotolerance and diversity indices of microflora of Indian white prawn (Fenneropenaeus indicus) after high pressure (HP)-treatment. Indian white prawns subjected to HP-treatments and its effect was studied up to species level and compared with unpressurized samples. The bacterium was identified by using bacterial identification schemes, biochemical tests and API

The pressure effect on the electromotive force (EMF) of a Pt13Rh–Pt (type R) thermocouple was examined to determine the temperature measurement accuracy of solid pressure medium apparatuses in high-pressure experiments. Single-wire EMFs were measured up to pressure of 13 GPa and temperature of 1173 K with a Kawai-type multi-anvil apparatus for Pt13Rh and Pt based on the single-wire method. The pressure

The numerical shock velocity–particle velocity data were obtained by the use of the conservative laws and data were fitted to the linear and quadratic relation with respect to the particle velocity in various temperatures. An equation was derived for the second parameter of the general Hugoniot relation that could be obtained at every initial temperature loading by the use of the existing equation

We present a simple and effective approach to improve X-ray data collected under extreme conditions of pressure and temperature. The X-ray data of the sample and the amorphous, liquid, or crystalline pressure transmitting media (PTM) which surround the sample are collected separately at each pressure and temperature, allowing a satisfactory background subtraction. Using this method, we are able to

Electrical and thermal transport properties of iron are of great importance for understanding the thermal evolution and dynamics of the Earth’s core, of which iron is a major component. However, the reported values of iron’s conductivity at core conditions are still highly controversial. In this study, we employed an internally resistive heated diamond anvil cell (IHDAC) technique that reduces temperature

Almost completely dense (>99%) TiC composites toughened by TiSi2-SiC agglomerates were fabricated by high pressure in-situ reaction sintering of TiC and Si at a lower temperature of 1150°C. In the agglomerates of TiSi2 and SiC interlocking structures, the size of TiSi2 particles is controlled on the nanometer and submicron scales. The precursors used in the preparation were TiC and Si. The addition

A high pressure low-temperature neutron diffraction study has been carried out on rare earth metal Dysprosium (Dy) to 10.8 GPa and 8 K in a large-volume diamond anvil cell using a spallation neutron source. Dy crystallizes in an ambient pressure hexagonal close packed phase and forms an incommensurate helical antiferromagnetic phase, marked by the appearance of superlattice magnetic peaks below 176

Living species inhabiting ocean deeps must adapt to high hydrostatic pressure. This adaptation, which must enable functioning under conditions of promoted protein hydration, is especially important for proteins such as cytochromes P450 that exhibit functionally important hydration-dehydration dynamics. Here we study the interactions of substrates with cytochrome P450-SS9, a putative fatty acid hydroxylase

The in-situ observation of pressure inside a sample chamber was made by exploiting the piezoelectric effect in manganin wire. This was done by considering temperatures of room temperature (±1°C), 600°C (±3°C), and 900°C (±3°C), pressure range of 0–2.4 GPa (±0.1 GPa), and the inferring a relationship between the relative resistance of manganin wire and the pressure inside the sample chamber for the

The molar volumes of tetracyanoethylene (1), maleic anhydride (2), N-phenylmaleimide (3), anthracene (4), trans, trans-1,4-diphenyl-1,3-butadiene (5), and their Diels–Alder reaction adducts (6 -9) in the solid state (Vcr) and in solutions (VS) were determined. The reaction volume due to the reorganization of the bonds (Δr-n VW) is nearly the same as in solid state (Δr-n Vcr) and both values are only

We present experimental results on melting and subsolidus phase relations in the Ni–Ni2P system at 6 GPa and 900–1600°C. The system has four stable phosphides: Ni3P nickelphosphide, Ni8P3/Ni5P2, Ni12P5 and Ni2P transjordanite. The Ni12P5 phase becomes unstable at 900°C and decomposes into Ni5P2 and Ni2P. The eutectic Ni–Ni3P locates at 950°C and 20 mol% P. Ni3P melts incongruently at 1075°C to Ni5P2

Ensuring hydrostatic conditions in high pressure experiments is of utmost importance for obtaining reproducible and comparable dataset. Here, we investigate the degree of hydrostaticity of four pressure-transmitting media (PTM), three alkali halides and polyethylene, commonly used in infrared (IR) spectroscopy using multiple rubies as pressure sensors within a diamond anvil cell (DAC) pressure cavity

We analyzed the compression process of the centrally caved Bridgman-anvil cell by a simplified mechanics model and proposed that the pressure limitation for a given configuration is governed by the compressibility and compression ratios (V0/V) of the gasket and sample. Then we replaced the middle part of the sample that is prone to undergo plastic deformation with a diamond plate, which will obviously

Beetroot juice is a source of polyphenols and betalains. Betalains serve both as colourants and bioactive compounds, and are known to be sensitive to temperature. Conventional thermal treatments can significantly affect the visual appearance and the nutritional quality of beetroot juice and, in consequence, the ultimate consumer acceptance. Our aim is therefore to evaluate the effects of an alternative

Phase relations in the CaCO3–CaSiO3 system have been studied at 6 GPa and 1300–1750°C. At 1300°C, the subsolidus assemblage comprises of aragonite and walstromite. The eutectic was established at 1400°C and 57 mol% CaSiO3. Just below its melting temperature at 1660°C, the CaCO3 solid quenches to calcite, while, at ≤1600°C, it quenches to aragonite. At 1700°C, a walstromite + larnite + liquid assemblage

High-entropy alloys (HEAs) attract growing interest due to their remarkable properties. However, our knowledge of the mechanism of phase stability of HEAs is still very limited. Herein, CoCrFeNixAl1-x (x = 0.5 and 0.75) were compressed to high pressures to investigate the lattice distortion effect on their phase stability. It was discovered that both bcc CoCrFeNi0.5Al0.5 and fcc CoCrFeNi0.75Al0.25