Extreme Pressure Conditions Research Articles

Possible alternatives to critical elements in coatings for extreme applications

Surface functionalisation and protection have been used since a long time for improving specific properties of materials such as lubrication, water repellence, brightness, and for increasing durability of objects and tools. Among the different kinds of surface treatments used to achieve the required properties, the use of coatings is fundamental to guarantee substrate durability in harsh environments. Extreme working conditions of temperature, pressure, irradiation, wear and corrosion occur in several applications, thus very often requiring bulk material protection by means of coatings. In this study, three main classes of coatings used in extreme conditions are considered: i) hard and superhard coatings for application in machining tools, ii) coatings for high temperatures (thermal barrier coatings), and iii) coatings against corrosion. The presence of critical elements in such coatings (Cr, Y, W, Co, etc.) is analysed and the possibility to use CRMs-free substitutes is reviewed. The role of multilayers and nanocomposites in tailoring coating performances is also discussed for thermal barrier and superhard coatings.

Fabrication of microelectrodes on diamond anvil for the resistance measurement in high pressure experiment

Diamond anvil cell techniques are now well established as a powerful and wide useful method to measure the properties of materials in the very high pressure experiment. However, the measurement of material resistance at the high pressure in the experiment is a big challenge because the electrodes are difficult to be made on the diamond anvil with small top area of the 0.3 mm diameter and have good contact with the sample under the extreme high pressure conditions. In this paper, a new method is used to fabricate the microelectrodes on the diamond anvil surface for the high pressure experiment. Firstly, a special Nickel shadow mask with the electrode patterns, which is made by micro-fabrication technology, is installed and fixed onto the diamond anvil surface with the glue by aligning the electrodes of the shadow mask with the center of the diamond anvil under the microscope. Then, the metal film is deposited onto the anvil with nickel shadow mask by magnetron sputtering. Finally, the microelectrodes having the same patterns with the hollowed structures of the shadow mask can be made with the sputtering material to adhere on the diamond anvil surface after the removal of the shadow mask off the anvil. This new method is simpler, easier to be operated, and less pollution produced to the diamond anvil cell than the traditional method.

Modelling the radiolysis of RSG-GAS primary cooling water

Water chemistry control for light water coolant reactor required a reliable understanding of radiolysis effect in mitigating corrosion and degradation of reactor structure material. It is known that oxidator products can promote the corrosion, cracking and hydrogen pickup both in the core and in the associated piping components of the reactor. The objective of this work is to provide the radiolysis model of RSG GAS cooling water and further more to predict the oxidator concentration which can lead to corrosion of reactor material. Direct observations or measurements of the chemistry in and around the high-flux core region of a nuclear reactor are difficult due to the extreme conditions of high temperature, pressure, and mixed radiation fields. For this reason, chemical models and computer simulations of the radiolysis of water under these conditions are an important route of investigation. FACSIMILE were used to calculate the concentration of O2 formed at relatively long-time by the pure water γ and neutron irradiation (pH=7) at temperature between 25 and 50 °C. This simulation method is based on a complex chemical reaction kinetic. In this present work, 300 MeV-proton were used to mimic γ-rays radiolysis and 2 MeV fast neutrons. Concentration of O2 were calculated at 10−6 - 106 s time scale.

Beach to Bench to Bedside: Marine Invertebrate Biochemical Adaptations and Their Applications in Biotechnology and Biomedicine.

The ocean covers more than 70% of the surface of the planet and harbors very diverse ecosystems ranging from tropical coral reefs to the deepest ocean trenches, with some of the most extreme conditions of pressure, temperature, and light. Organisms living in these environments have been subjected to strong selective pressures through millions of years of evolution, resulting in a plethora of remarkable adaptations that serve a variety of vital functions. Some of these adaptations, including venomous secretions and light-emitting compounds or ink, represent biochemical innovations in which marine invertebrates have developed novel and unique bioactive compounds with enormous potential for basic and applied research. Marine biotechnology, defined as the application of science and technology to marine organisms for the production of knowledge, goods, and services, can harness the enormous possibilities of these unique bioactive compounds acting as a bridge between biological knowledge and applications. This chapter highlights some of the most exceptional biochemical adaptions found specifically in marine invertebrates and describes the biotechnological and biomedical applications derived from them to improve the quality of human life.

Effect of hydrothermal carbonization on dewatering performance of dyeing sludge.

The effects of hydrothermal carbonization (hydrothermal carbonization temperature, hydrothermal carbonization time, pH) on the dehydration performance of dyeing sludge were studied. The specific resistance, viscosity and floccular morphology of sludge before and after hydrothermal carbonization were analyzed. The physical and chemical properties of the liquid were also determined. The results showed that the dehydration performance of sludge was optimum, when the reaction temperature was 180 °C, the reaction time 4 h and the pH was 5.0. Here the specific resistance to filtration and viscosity were 93.69% and 96.78% lower, respectively, than the control group. When the sludge was hydrothermally carbonized, the sludge flocs were broken due to extreme conditions of high temperature and high pressure, which formed a porous mesh structure with better water permeability. The cohesion of the sludge colloidal structure was reduced, the capillary suction time was reduced by 88.89%, and the sludge dewatering performance was improved. This study shows the feasibility of the use of hydrothermal carbonization in sludge reduction.

Consequence Analysis of LPG Storage Tank

Consequence modeling refers to the calculation or estimation of numerical values (or graphical representation) that describes the credible physical outcomes of loss of containment scenarios involving f1ammable explosive and toxic materials with respect to their impact on people, assets or safety functions. The need to risk assessment and consequence modelling of process plant and hazardous storage facilities has become exceedingly critical due to the trend towards larger and more complex units that process toxic, flammable and otherwise hazardous chemicals under extreme temperature and pressure conditions. Moreover, the proximity of many such units to densely populated areas may magnify the potential damage. There are several types of explosion including deflagration, detonation, dust explosion, vapor cloud explosion and boiling liquid expanding vapour explosion (BLEVE). PHAST RISK analyses complex consequences from accident scenarios, taking account of local population, land usage and weather conditions, to quantify the risk associated with the release of hazardous materials. In this project consequence analysis of LPG sphere is performed by PHAST 6.5.

A laser heating facility for energy-dispersive X-ray absorption spectroscopy.

A double-sided laser heating setup for diamond anvil cells installed on the ID24 beamline of the ESRF is presented here. The setup geometry is specially adopted for the needs of energy-dispersive X-ray absorption spectroscopic (XAS) studies of materials under extreme pressure and temperature conditions. We illustrate the performance of the facility with a study on metallic nickel at 60 GPa. The XAS data provide the temperature of the melting onset and quantitative information on the structural parameters of the first coordination shell in the hot solid up to melting.

Research on the Effect of Applying the Sacrifice Layer Technique on the Chemical Composition of the Welded Deposits

All vessel-type products operating under extreme conditions of temperature, pressure and corrosive environments, such as those in the power, chemical and petrochemical industries, are subjected to intense chemical / structural degradation processes that may lead to cracks. These may propagate in time, causing the product to fail, generating significant economic and material consequences, leading in some cases even to the loss of human lives. The paper presents some effects of the sacrifice layer repairing technique used to restore the geometrical shape by welding of the area from where the flaw material was removed, on the chemical composition.

MECHANICAL PROPERTIES OF PALM KERNEL OIL-COPPER OXIDE NANOLUBRICANT

Since the last decade, vegetable oil has received tremendous attention as an alternative lubricant because of worsening state of environmental health and finite resources of mineral oil. However, the use of vegetable oil is restricted due to the poor low temperature fluidity and thermal-oxidative stability. These drawbacks can be enhanced by adding additive into the solution of vegetable oil. Thus, objective of this research is to investigate the influence of adding nanoparticle additive on tribological performance of palm kernel oil. The type of nanoparticle used throughout this study is copper oxide, which serves as anti-wear additive. Palm kernel oil (PKO), palm kernel oil-copper oxide nanoparticle (PKO-CuO), mineral oil (SAE-40), synthetic oil (SAE15W-50) are used as lubricant. Tribological properties if the used lubricants are evaluated using fourball tribotester under standard load and extreme pressure tests. Experimental results showed that the presence of nanoparticles in natural palm kernel oil improved tribological performances of friction and wear. The friction coefficient and wear scar diameter are reduced by approximately 5.0% and 3.5% respectively. The highest enhancement in friction coefficient value of ~20% was obtained under extreme pressure condition. Addition of nanoparticle also is found to improve load carrying capacity of PKO by 15%.

The rheology of drilling fluids from a non-equilibrium thermodynamics perspective

The rheological behavior of drillings fluids is usually described by the Casson or the Herschel- Bulkley models. Despite the overwhelming data highlighting the significance of their use in numerous fields, they fail to produce normal stresses, whose importance in drilling operations has only recently attracted attention. We herein introduce a continuum model for predicting the rheological behavior of drilling fluids with plate-like suspensions, based on the Hamiltonian formulation of transport phenomena for fluids with a complex microstructure. The model describes drilling fluids at a mesoscopic level by using two fields: a vectorial (the momentum density) and a tensorial one (the particle's orientation tensor). A thorough comparison against experimental data demonstrates the unique capability of the new model to accurately describe the rheological behavior of these systems, for both shear viscosity and normal stresses. Future work, aiming to improve the predictive capacity of the model at higher volume fractions and for considering the extreme temperature and pressure conditions frequently encountered in borehole operations, are also discussed.

Applications of nanocomposite hydrogels for biomedical engineering and environmental protection

Nanocomposite hydrogels are polymeric networks that possess a unique property of hydration. The presence of alcohols, carboxylic acids and amides as hydrophilic moieties in structure of nanocomposite hydrogels enhances their stiffness and water-absorbing capacity. Addition of cross-linker in the synthesis of hydrogels increases their stability under extreme conditions of temperature, pH and pressure. Natural polymer-based nanocomposite hydrogels are biodegradable, highly hydrophilic and possess good mechanical strength. Gelatin, chitin, cellulose, pectin, carrageenan, starch and alginate are natural polymers commonly used to fabricate nanocomposite hydrogels. Nanocomposite hydrogels have special characteristics such as high swelling rate, selectivity and stimuli-sensitive nature. Here we review nanocomposite hydrogels for environmental protection and biomedical engineering. Applications in biomedical engineering include drug delivery agents, wound dressing, tissue engineering and antibacterials. Applications in environmental protection include ion exchangers, adsorption, photocatalysis and soil conditioning. Many nanocomposite hydrogels show excellent adsorption selectivity for heavy metal ions: Cu2+ up to 30.35 mg/g, Pb2+ up to 35.94 mg/g, and Zn2+ and Fe3+ up to 94.34 mg/g. Xanthan gum-based nanocomposite hydrogel has removed 96% dye from industrial effluent as reported. In addition, most of the nanocomposite hydrogels showed better adsorption capacity for pollutants in the pH range from 5 to 7. The nanocomposite hydrogels could also be regenerated and successfully utilized for several times. Nanocomposite hydrogels are therefore good bio-absorbent materials for environmental detoxification.

Effect of cutting fluids on corrosion properties and turning surface quality of Fe-based superalloy

As the steam turbine rotor works in extreme conditions of high temperature, pressure, speed, and load, better material performance and machined surface quality are highly demanded. Fe-based superal...

Novel boron channel-based structure of boron carbide at high pressures

Boron carbide (B4C) is one of the hardest materials known to date. The extreme hardness of B4C arises from architecturally efficient B12 or B11C icosahedrons and strong inter-icosahedral B–C bonding. As an excellent material for use in ballistic armor, the mechanic limit of B4C and possible phase transitions under extreme stress conditions are of great interest. Here we systematically explored the post-icosahedral solid structures of B4C under high pressure, using an unbiased structure search method. A new structure composed of extended framework of B and zigzag chains of C is predicted to be stable above 96 GPa. The new structure was predicted to have a high Vickers hardness of 55 GPa and simultaneously to retain a metallic ground state. The exceptional mechanical properties found in this structure are attributed to strong sp3 covalent network formed under extreme pressure conditions. The predicted structure represents a new type of superhard boron carbides that form under high pressure without the presence of boron icosahedrons, which encourages experimental exploration in this direction.

Joint AIRAPT-25th and EHPRG-53rd International Conference on High Pressure Science and Technology

The AIRAPT arose as a scientific forum for discussions aiming to promote contacts and cooperation between scientists and organizations of different countries, to collect and disseminate of information, having the advancement of science and technology in the field of high pressure as main objective.Nowadays the field has experienced an astonishing growth in an open multidisciplinary environment that rather contributed to the creation of different interdisciplinary teams of excellence, being able to face the important challenges posed by high-pressure research. Great achievements have been possible towards higher pressures, nowadays making possible experiments in the TPa range in our laboratories, the improvement and adaptation of different characterization techniques of matter under extreme conditions of pressure and temperature or the development of efficient ab initio methods with capabilities to explain and eventually predict new physical phenomena and materials design. All decisively contributed to the advance of science and understanding of nature, with high pressure as common leitmotiv.On the 50th Anniversary of the AIRAPT, this talk will is intended to commemorate the enthusiastic and encouraging work of high-pressure pioneers and to motivate young scientists to join us and continue the challenge of exploring compressed matter as a way to unveil new phenomena and materials and a better understanding of our world.

Temperature dependence of the extreme-pressure behavior of CuO and TiO2 nanoparticle additives in metal-forming polymeric lubricants

PurposeThe purpose of this work is to investigate the effect of temperature on the extreme-pressure (EP) properties of CuO and TiO2 nanoparticle-filled polymeric lubricants for metal-forming processes.Design/methodology/approachThis paper studies the effect of nanoparticle additives of CuO and TiO2 on the load-carrying capacity of a metal-forming polymer lubricant used for deep-drawing at varying temperatures. EP measurements are performed with a four-ball tribotester according to the ITeE-PIB Polish method for testing lubricants under scuffing conditions. Tests are run at 25, 40, 60 and 75°C to further decrease the lubricant film thickness and determine the effect on the load-carrying capacity and the tribological mechanisms of nanoparticles. The tribological mechanisms of nanoparticles is studied using energy dispersive spectrometry (EDS).FindingsResults indicate that nanoparticle additives increase the load-carrying capacity of the polymeric lubricant at all concentrations up to 60°C attributed to a mending effect and a reduction in the area of contact of moving surfaces; at 75°C, the improvement is lowered due to nanoparticle re-agglomeration. The best results are found with TiO2 nanoparticles due to their smaller size compared to CuO.Practical implicationsNanoparticles of CuO and TiO2 are potential EP additives for metal-forming lubricants, providing protection to working components and extending tool life.Originality/valueThese results show the effectiveness and the tribological mechanisms of nanoparticle additives under EP conditions and increasing temperatures found in metal-forming processes.

A new proxy application for compressible multiphase turbulent flows

CMT-nek is a simulation code for performing high fidelity, predictive simulations of particle laden explosively dispersed turbulent flows under conditions of extreme pressure and temperature. CMT has many applications including lithotripsy, dust explosions in coal mines, and explosive detonation. The physical processes underlying these applications are complex and cover a very wide range of spatial and temporal scales.The underlying workflow of this application requires a very rich set of computation on multiple types of data structures and data access patterns. Additionally, the simulation of such codes require high spatial and temporal resolution resulting in large memory footprint and enormous computing power that is only available on extant petascale and exascale supercomputers. The workflow and the underlying patterns are representative of other scientific applications and hence have the potential to serve as an important benchmark for next generation supercomputers.In this paper,11A preliminary version of this work will appear in Proceedings of HiPC 2016, “CMT-bone: A Proxy Application for Compressible Multiphase Turbulent Flows”, by Tania Banerjee, Jason Hackl, Mrugesh Shringarpure, Tanzima Islam, S. Balachandar, Thomas Jackson and Sanjay Ranka. we describe CMT-bone that serves as a proxy-app for CMT-nek. Proxy applications provide a simplified framework for computational scientists and system designers to investigate new node architectures, programming approaches, algorithmic design choices and optimization techniques. CMT-bone retains the workflow of CMT-nek and encapsulates key data structures, computational and communication patterns of CMT-nek. It reduces the number of variables used and corresponding compute and communication operations performed at each step of the work.Validation of CMT-bone with the CMT-nek using the veritas tool developed at LLNL shows that CMT-nek is a good proxy. Such a validation is important as it shows that important computational characteristics of CMT-nek are embedded in CMT-bone and any experimental performance analysis of the latter will be representative of the former.

Studies of the Core Conditions of the Earth and Super-Earths Using Intense Ion Beams at FAIR

Abstract Using detailed numerical simulations, we present the design of an experiment that will generate samples of iron under extreme conditions of density and pressure believed to exist in the interior of the Earth and interior of extrasolar Earth-like planets. In the proposed experiment design, an intense uranium beam is used to implode a multilayered cylindrical target that consists of a thin Fe cylinder enclosed in a thick massive W shell. Such intense uranium beams will be available at the heavy-ion synchrotron, SIS100, at the Facility for Antiprotons and Ion Research (FAIR), at Darmstadt, which is under construction and will become operational in the next few years. It is expected that the beam intensity will increase gradually over a couple of years to its maximum design value. Therefore, in our studies, we have considered a wide range of beam parameters, from the initial beam intensity (“Day One”) to the maximum specified value. It is also worth noting that two different focal spot geometries have been used. In one case, a circular focal spot with a Gaussian transverse intensity distribution is considered, whereas in the other case, an annular focal spot is used. With these two beam geometries, one can access different parts of the Fe phase diagram. For example, heating the sample with a circular focal spot generates a hot liquid state, while an annular focal spot can produce a highly compressed liquid or a highly compressed solid phase depending on the beam intensity.

Optical Emission in Hexagonal SiGe Nanowires

Recent advances in the synthetic growth of nanowires have given access to crystal phases that in bulk are only observed under extreme pressure conditions. Here, we use first-principles methods based on density functional theory and many-body perturbation theory to show that a suitable mixing of hexagonal Si and hexagonal Ge yields a direct bandgap with an optically permitted transition. Comparison of the calculated radiative lifetimes with typical values of nonradiative recombination mechanisms indicates that optical emission will be the dominant recombination mechanism. These findings pave the way to the development of silicon-based optoelectronic devices, thus far hindered by the poor light emission efficiency of cubic Si.

Roald Hoffmann

Roald Hoffmann

Studies of the mechanical and extreme hydrothermal properties of periodic mesoporous silica and aluminosilica materials

In order to assess the suitability of mesoporous materials for applications in energy harvesting/storage processes occurring under extreme conditions, their mechanical, thermal and hydrothermal properties need to be fully investigated. In this study, the bulk mechanical and extreme hydrothermal properties of periodic mesoporous SBA-15 type silica and SBA-15 type aluminosilica (Al-SBA-15) were investigated using in situ small angle x-ray scattering (SAXS). In situ SAXS measurements were made on dry mesoporous SBA-15 silica and Al-SBA-15 aluminosilica samples as a function of pressure (at room temperature) to ∼ 12 GPa and on the same mesoporous materials under extreme hydrothermal conditions (to 255 °C and ∼114 MPa) using the diamond anvil cell (DAC). The analyses of the high-pressure SAXS data indicate that the mesoporous Al-SBA-15 aluminosilica has substantially greater bulk mechanical stability (isothermal bulk modulus κ = 34.7(4.5) GPa) than the mesoporous SBA-15 silica (κ = 12.0(3.0) GPa). Our molecular dynamics (MD) simulations are able to accurately model the bulk mechanical stability properties of mesoporous SBA-15 silica but underestimate the same properties of Al-SBA-15 aluminosilica. Analysis of the in situ SAXS data measured under extreme hydrothermal conditions indicates swelling of the pore walls due to water incorporation that is more significant in mesoporous Al-SBA-15 aluminosilica (∼2x) than in SBA-15 silica. In addition, the Al-SBA-15 aluminosilica clearly exhibits superior hydrothermal stability compared to SBA-15 silica under the extreme experimental temperature and pressure conditions.