Use In Extreme Conditions Research Articles

Mono- and di-rhamnolipids mixtures from Pseudomonas aeruginosa for use in extreme conditions of pre- and post-salt oil reservoirs compared with synthetic surfactants

Rhamnolipids are multipurpose molecules known as natural glycolipid biosurfactants that are often biosynthesized by Pseudomonas aeruginosa strains. They are readily biodegradable, have less impact on the environment and are less toxic than conventional surfactants. They can be applied in ex situ microbial enhanced oil recovery. However, there is still a lack of knowledge concerning the drastic environmental conditions of post and pre-salt reservoirs. In this study, different mixtures with different proportions of homologs of rhamnolipids from two genetically modified strains (GMOs) of P. aeruginosa and a non-GMO strain compared to commercial surfactants (Arquad C-50 and/or Ultrasperse II®) regarding their efficiency under high pressure, temperature and salinity conditions. Wettability reversal and interfacial tension tests were performed together with central composite rotational designs. Both genetically modified P. aeruginosa strains produced mainly di-rhamnolipids, whereas the non-GMO strain produced approximately 50 % mono- and 50 % di-rhamnolipids. Rhamnolipids and Arquad C-50 reversed 100 % of the wettability under pre-salt and post-salt conditions, whereas Ultrasperse II® achieved 73.3 % and 34.2 % (100 ppm) wettability, respectively. Interfacial tension presented the lowest values for rhamnolipids, with values of 0.4 mN/m and 0.5 mN/m, whereas Ultrasperse II® presented values of 2.6 and 2.5 mN/m, respectively under post-salt and pre-salt conditions at the +1 level of the tested variables. All rhamnolipid congeners tested here were more effective under post and pre-salt reservoirs conditions than commercial surfactants, thus expanding their potential for use not only in environmental bioremediation but also in oil industry processes.

Repair and Reuse of Spent Lithium Battery Electrode Materials

With the popularity of new energy vehicles and various electronic devices, the use of lithium-ion batteries (LIBs) has shown explosive growth, which has resulted in a large number of spent LIBs. Spent LIBs contain a large amount of metal resources, and improper disposal will not only cause waste of resources, but also have potential environmental risks. The existing commercial recycling methods are mainly pyrometallurgy and hydrometallurgy recycling methods, both of which require re-extraction from the electrode material after destroying them to the atomic level for the preparation of new electrode materials, which is a long process with high cost, and involves the application of extreme conditions such as high temperature and strong acid, with inferior economic and environmental benefits. It is a major challenge in the field of battery recycling to develop innovative and clean recycling methods, to simplify the recycling process and to develop ways to reuse the recovered products. In view of the challenge of existing recycling methods, the reporters proposed the idea of direct recycling of electrode materials at the molecular scale, and designed innovative recycling methods such as direct repair of degraded lithium cobalt oxides with deep eutectic solvent (DES), repair of Ni-Mn-Co ternary (NCM) cathode with high failure degree by low temperature molten salt, and thermal regeneration of degraded lithium iron phosphate (LFP) with multifunctional solvent; and closed-loop design of the direct recycling process. In addition, we propose a high-value utilization path for the conversion of degraded electrode materials to high-performance electrode materials and nano-catalysts. It greatly simplifies the recycling process, avoids the use of extreme conditions, and provides a new technical system and theoretical guidance for battery recycling research and industry.

Volatile and thermally stable tungsten organometallic complexes (RCp)W(CO)2(η3-2-tert-butylallyl) as potential thin film deposition precursor

Two organometallic tungsten complexes (RCp)W(CO)2(η3-2-tert-butylallyl) (R = methyl or ethyl, Cp = cyclopentadienyl) as precursors capable of growing tungsten-containing thin films, are constructed bearing heteroleptic ligand system. The syntheses adopt a rationally designed approach excluding the use of extreme conditions and involving facile purification procedures. The two complexes are authenticated by nuclear magnetic resonance (NMR) and elemental analysis, as well as Fourier transform-infrared (FT-IR) spectroscopy. Thermal property evaluations, including thermogravimetric and vapor pressure tests, reveal favorable thermal stability and volatility which are essential for a typical ALD process. It is noteworthy that both precursors possess relatively low-melting point and specifically, the one bearing ethyl-Cp group is in liquid phase at room temperature. Such design concept of heteroleptic ligand system and substructure tuning pave the way to develop liquid precursors which are imperative demand in microelectronic industry.

Simultaneously significant transparency enhancement and efficient temperature feedback achieved in AlON ceramic through luminescent rare earth doping

Activator-doped aluminum oxynitride (γ-AlON) could provide an extremely versatile transparent ceramic with photothermal feedback, opening the door to many new applications and devices for use in extreme conditions. However, existing AlON transparent ceramics have failed to achieve temperature-responsive luminescence. To address this, a simple-to-implement luminescent rare-earth doping strategy for fabricating AlON transparent ceramic with efficient temperature feedback is proposed and demonstrated. Luminescent Pr2O3 serves as the illustrative example. Benefiting from the liquid phase formed by Pr2O3 and the thermal coupling between the 3P1 and 3P0 levels of Pr3+, AlON ceramics doped with Pr2O3 exhibit significantly elevated transparency and temperature-responsive luminescence. More importantly, the AlON:Pr ceramic can serve as photothermal feedback windows, which presents attractive performance. This paradigm fills an important gap in the AlON transparent ceramics for temperature feedback windows, and will inspire the controllable design of luminescent rare-earth doped AlON ceramics for use in harsh conditions.

Prospects of using functional training in the process of physical training of cadets

The professional activity of military personnel is always associated with high risk, which includes both psychological aspects and physical aspects. Work experience confirms that the quality of mastering combat techniques for use in extreme conditions depends on the level of development of mental preparedness and endurance. Including elements of functional training in physical training can significantly contribute to the development of endurance, strength, coordination, and psychological stability. Endurance as a physical quality is characterized by the ability to perform tasks for a long time. Modern conditions in which military personnel perform their tasks, despite the presence of the latest military equipment and vehicles, require them to have a high level of development of this quality in order to carry out foot crossings, overcome areas of terrain with various artificial and natural obstacles. In the course of functional training, strength endurance is developed, which allows you to perform physical tasks for a long period of time. This can be especially useful in military service or other situations where it is necessary to maintain a high level of physical activity for a long time.
 The basic idea of functional training is to use exercises that activate many muscle groups at the same time and imitate movement patterns that can be encountered in everyday life or during sports activities.
 Functional training also improves cardiovascular endurance by increasing the efficiency of the cardiovascular system and the body's ability to work at an elevated heart rate. Such training may include elements of exercises with weights, a functional simulator, aerobics and other forms of physical activity aimed at comprehensive development. This method of training can be useful for improving general physical fitness, particularly in the context of military-professional activities, as it promotes the development of functional strength endurance and adaptive readiness for various physical challenges.

High-pH mobile phase in reversed-phase liquid chromatography-tandem mass spectrometry to improve the separation efficiency of aminoglycoside isomers.

In chromatography, the use of extreme conditions can often lead to unique separation selectivity. In this study, a highly basic mobile phase (pH > 11), which is not typically employed for reversed-phase liquid chromatography (RPLC), was utilized in RPLC-tandem mass spectrometry (MS/MS) to achieve effective separation between electrically neutral bases of aminoglycosides (AGs). A mixture of AGs was simultaneously analyzed using 500mmol L-1 ammonia aqueous solution (pH 11.8) as the mobile phase. A total of 11 AGs, including 2 stereoisomers of neomycin (B and C) and 5 structurally similar components of gentamicin (C1, C1a, C2, C2a, and C2b), were completely separated for the first time. The high separation performance for AGs was mainly due to two factors: First, slight differences in hydrophobicity among the AGs were significantly enhanced at a high pH by the complete acid dissociation of amines. Second, the high pH of the mobile phase minimized any electrostatic interactions between the AGs and residual silanol groups in the stationary phase, resulting in extremely sharp peaks for the AGs. The sensitivity of spectinomycin decreased by more than 20% when using the highly basic mobile phase (pH 11.8) due to its degradation, therefore, a mixture of 10 AGs was analyzed with 250mmol L-1 ammonia aqueous solution (pH 11.5) with less degradation as the optimum condition. The developed analytical method could be used to determine the concentrations of trace AGs in milk with high accuracy and precision. Thus, RPLC-MS/MS using a high-pH mobile phase has great potential for the efficient separation of basic compounds containing amino sugars such as AGs.

The effect of the introduction of single-walled carbon nanotubes on the electrical and mechanical characteristics of the ethylene tetrafluoroethylene

The possibility of obtaining antistatic and conductive composites based on an ethylene tetrafluoroethylene by introducing TUBALL single-wall carbon nanotubes deagglomerated in polyethylene wax has been established. The obtained antistatic composite (0.3–0.4 mass % of TUBALL nanotubes) has a set of mechanical characteristics sufficiently high for practical use as a structural material. This composite can be used in the development of products designed for use in extreme conditions in contact with chemically aggressive and flammable substances.

THE METHOD OF MULTI-CRITERIA ANALYSIS FOR DETERMINING THE FLOOD-HAZARDOUS AREA AND THE DEVELOPMENT OF PROTECTIVE STRUCTURES

Abstract. The city of Ust-Kamenogorsk, East Kazakhstan region, annually has a high risk of flooding and flooding of territories caused by spring snowmelt. These extreme phenomena are one of the most dangerous natural disasters, as they cause enormous socio-economic damage to the coastal settlements of the city. In the flood zone, agricultural and residential facilities, as well as engineering and technical infrastructure facilities are indicated. In some years, the funds allocated by the local buzhet to restore the damage caused by the disaster are not enough. One of the most effective means of stopping the consequences of such natural phenomena is an early warning system. Forecasting and modeling of hydrological phenomena can be provided using new IT technologies, some of which are Geoinformation technologies (GIS technologies) based on the cartographic method.In addition to modern advanced data processing methods in the GIS environment, the article presents a water collection design for emergency protection by calculating the main influencing factors of flooding and determining specific scales of flood levels in river valleys near settlements, determining the area of reservoirs collected at a risk control point at specific flood sites, as well as analyzing the detected ers material. The prospects for the use of GIS technologies as a means of forecasting and modeling floods caused by annual floods during the spring snowmelt period are also outlined, an analysis of the real situation is carried out, and a simple design of the shore for use in extreme conditions during periods of flooding is given.

Prediction of narrow HT-SMA thermal hysteresis behaviour using explainable machine learning

The ability to tailor narrow high-temperature thermal hysteresis behaviour in Ti-Ni-based high-transformation temperature shape memory alloys (HT-SMAs) is crucial for the development of the next-generation actuators intended for use in extreme conditions. Equally, the need and the development of tools to accurately predict shape memory alloys (SMA) transformation temperatures also becomes emergent. As such, the purpose of this study is to curate a small dataset from the experimental peer-reviewed literature and develop a practical data-driven machine learning (ML) based model to predict narrow hysteresis in HT-SMA transformations. This study compiles a small dataset based on experimental data and develops at least twelve candidate models using common machine learning and artificial neural network algorithms. Our results show that the XGBoost-based model exhibits the best performance in predicting the narrow thermal hysteresis behaviour in Ti-Ni-based HT-SMAs (i.e., the highest R2 = 0.893 and the lowest RMSE = 5.4). Further, using preselected case studies, the study demonstrates the utility of the relative feature importance, the accumulated local effects (ALE), and the SHapley Additive exPlanations (SHAP) model-agnostic techniques to interpret predicted outcomes and establish a more transparent relationship between the input materials composition descriptors and the predictions. These analyses demonstrate that the explainable ML approach offers practitioners a more transparent design tool, not only to predict the narrow hysteresis behaviour in HT-SMA transformations, but also a deeper understanding of how the input materials composition descriptors can contribute to its magnitude and/or directionality of the narrowing hysteresis.

Core-Shell Structured Carbon@Al2O3 Membrane with Enhanced Acid Resistance for Acid Solution Treatment.

Ceramic membrane has an important application prospect in industrial acid solution treatment. Enhancement of the acid resistance is the key strategy to optimize the membrane treatment effect. This work reports a core-shell structured membrane fabricated on alumina ceramic substrates via a one-step in situ hydrothermal method. The acid resistance of the modified membrane was significantly improved due to the protection provided by a chemically stable carbon layer. After modification, the masses lost by the membrane in the hydrochloric acid solution and the acetic acid solution were sharply reduced by 90.91% and 76.92%, respectively. Kinetic models and isotherm models of adsorption were employed to describe acid adsorption occurring during the membrane process and indicated that the modified membrane exhibited pseudo-second-order kinetics and Langmuir model adsorption. Compared to the pristine membrane, the faster adsorption speed and the lower adsorption capacity were exhibited by the modified membrane, which further had a good performance with treating various kinds of acid solutions. Moreover, the modified membrane could be recycled without obvious flux decay. This modification method provides a facile and efficient strategy for the fabrication of acid-resistant membranes for use in extreme conditions.

On the frontiers of coupled extreme environments

Coupled extreme environments pose among the highest demands on materials, stressing the limits of temperature, pressure, electric and magnetic fields, atomic displacement rates, and chemical potentials that can be simultaneously sustained. This issue highlights exciting new materials science methods that will enable rapid progress in what has traditionally been the most difficult materials arena. New opportunities in artificial intelligence, multi-physics simulations capabilities, the use of extreme conditions to synthesize novel materials, and our ability to interrogate materials under relevant conditions provide new avenues to understand and design new materials. Graphical abstract

Gradient ZrO2 nanocrystals strengthening electrospun SiC fibers

Ceramic ultrafine fibers (UFs) with flexibility and high strength have attracted considerable interest for use in extreme conditions. Herein, silicon carbide (SiC) UFs strengthening by gradient ZrO2 nanocrystals (NCs) were prepared by electrospinning, vacuum-maturating, and pyrolysis. Gradient NCs structure formed during vacuum-maturation can be classified as surface dense ZrO2 NCs, linear ZrO2 nanoclusters, and core homogeneous ZrO2 NCs. Notably, the obtained gradient ZrO2 NCs/SiC (g-ZS) UF exhibits 2.6 times higher strength and 1.8 times higher strain than SiC UF, which results in a high toughness (41.32 MJ m−3). The design strategy and fabrication method of such high strength with functional gradient NCs structure holds great promise for highly reliable micro/nanodevices and other ceramic ultrafine fibers.

Research on Hovercraft – Fatigue Cracks in the Engine Frame

Abstract Rescue patrol hovercrafts must meet the basic condition – high reliability of use in extreme conditions. The introduction to the work shows damage to the propulsion system and the fan tunnel structure resulting from a fatigue fracture of the attachment wound to the propulsion unit hull. In this paper, the author describes some ways of improving the engine frame structure. In the first phase of the exploitation crack testing of the hovercraft frame, the probable causes of damage were determined. The necessary output data for analysis of the load course were obtained from the operating documentation. The approximate number of variable load cycles acting on the frame truss rod was determined. Using the comparative testing methods, the service life of the frame was estimated. Probable resonance frequencies of the vibrating bars in the truss were determined. Vibration tests of the power transmission assemblies were carried out, which allowed to determine the amplitudes and frequencies of free vibrations. Finally, a modification of the frame shifting the resonant frequency range was proposed. In conclusions, changes to the design and a schedule of inspections were proposed. The newly designed engine frame should have an extended service life.

QUALITY ASSESSMENT OF FUR VELOUR

The paper offers a quantitative assessment of the quality of fur velour made of raw sheepskin and nutria skins obtained by the developed technologies. For this purpose, hydrophobized fur velour made of semi-fine-wool sheep skins and nutria skins with low-quality bristle hair has been used. The tanned semi-finished product of sheepskin and male nutria after moisture removal has been processed with a grinding skin of 4-5 grit. Fur velour is obtained from raw materials of inhomogeneous structure in different topographic areas, low density, but with satisfactory physical and mechanical properties of leather fabric, which in its quality meets standards requirements. The hydrophobization process is carried out with a composition based on α-alkenes С20–24 and maleic anhydride with an average molecular weight of 38‧103. According to the purpose of the research, a comprehensive assessment of the quality level of hydrophobized fur velour has been performed. A number of tasks have been implemented. Individual indicators of fur velour have been selected and ranked by experts. Their significance has been determined. The range of dimensional indicators of fur velour quality has been pointed out according to the scale of desirability. Desirability functions of velour quality significant indicators and complex quality index (CQI) of hydrophobized fur velour have been developed. The results of CQI development of sheepskin and nutria skins hydrophobized fur velour have been analyzed. CQI of hydrophobized fur velor and nutria skins, which includes 10 significant experimentally determined indicators has been calculated. According to the CQI, the hydrophobized velour material significantly outperforms fur velour obtained by standard technologies, especially after its sprinkling. Hydrophobized velour of sheepskin and nutria is characterized by a higher thermal resistance of 1.17 and 1.15 times, respectively, in comparison with control samples. The obtained materials can be effectively used to manufacture clothing items suitable for use in extreme conditions under rain and snow.

Flexible porous SiZrOC ultrafine fibers for high-temperature thermal insulation

Ceramic fibers with combined properties of high flexibility, thermal stability and thermal insulation performance are attractive for use in extreme conditions. In this work, the porous SiZrOC ultrafine fiber (PSUF) composed of SiO2, ZrO2, SiOxCy and free carbon phases was firstly prepared by electrospinning technique. The resulting PSUF exhibited integrated properties of high flexibility and high-temperature stability. More importantly, comparing with solid SiZrOC fiber, the fancy porous structure made the thermal conductivity of PSUF decreased 16.6% to 0.141 W m−1·K−1 at 1000 °C. The successful fabrication of such flexible PSUF may provide a new approach to design high performance thermal insulators for high-temperature thermal insulation.

Self-powered soft robot in the Mariana Trench.

The deep sea remains the largest unknown territory on Earth because it is so difficult to explore1-4. Owing to the extremely high pressure in the deep sea, rigid vessels5-7 and pressure-compensation systems8-10 are typically required to protect mechatronic systems. However, deep-sea creatures that lack bulky or heavy pressure-tolerant systems can thrive at extreme depths11-17. Here, inspired by the structure of a deep-sea snailfish15, we develop an untethered soft robot for deep-sea exploration, with onboard power, control and actuation protected from pressure by integrating electronics in a silicone matrix. This self-powered robot eliminates the requirement for any rigid vessel. To reduce shear stress at the interfaces between electronic components, we decentralize the electronics by increasing the distance between components or separating them from the printed circuit board. Careful design of the dielectric elastomer material used for the robot's flapping fins allowed the robot to be actuated successfully in a field test in the Mariana Trench down to a depth of 10,900metres and to swim freely in the South China Sea at a depth of 3,224metres. We validate the pressure resilience of the electronic components and soft actuators through systematic experiments and theoretical analyses. Our work highlights the potential of designing soft, lightweight devices for use in extreme conditions.

Anomalous concentration dependence of the thermal conductivity of refractory sintered binary nano-composites TiN-ALN and ZrC-ZrB2

An abnormal concentration dependence of the thermal conductivity of nanocomposites Titanium Nitride-Aluminum Nitride and zirconium carbide-zirconium diboride has been experimentally established from the volume fraction of components. An explanation of the nature of the anomalous dependence and a technique for an approximate estimation of the dependence of the thermal conductivity of a nanocomposite on the volume fraction of components are proposed. Oxygen-free refractory compounds - covalent and metal-like active investigated in the development of new ceramic materials used for achieving higher physical and mechanical characteristics as well as for use in extreme conditions in mechanical engineering, nuclear engineering, aviation, special equipment. The development of technology is constantly stimulates the creation of new materials, which must manifest a complex of properties rarely show by one substance, such decisions cannot find the formation of composite (hetero) materials. In the case of eutectic systems with diffusive non-interacting refractory components, used for the synthesis of composite ceramic materials in a highly thermodynamic state, the possibility of co-building a new group of ceramics with interphase boundary (of eutectics “coarse conglomerate”) with anomalous concentration dependences of the physical and mechanical characteristics of composite materials (flexural strength and modulus of elasticity, super plasticity – elongation more than 500%, tensile, strength and fracture toughness) and thermal properties (thermal conductivity and thermal diffusivity) [1-3].

Alkaline extraction and carboxymethylation of xylans from corn fiber

In the corn crop industry, of all the biomass produced, about 80% are residues. The so-called corn fibers, one of the most important residues of the corn processing industry, represent about 9% of the corn kernel weight, being a low value material that could, potentially, be used for making higher added value products. This work aimed to extract the hemicelluloses present in the corn fiber via alkaline extraction, with their subsequent functionalization for production of carboxymethyl xylans in mild conditions. The corn fibers were characterized for their contents of carbohydrates, lignin, extractives, total uronic acids, acetyl groups, and ash. Their arabinoxylans were extracted by 2–18% (w/v) sodium hydroxide at room temperature, for 5 h at 10% consistency, precipitated with ethanol, washed and then vacuum dried. The resulting extract was characterized by FT-IR, viscosity, arabinoxylan content and purity. It was demonstrated that CCE treatment provides a high purity and little degraded xylan, but the extraction yields are relatively low, in the range of 4.0–23.9% wt/wt depending upon extraction conditions. The use of corn fiber arabinoxylans to obtain hemicellulosic derivatives through chemical modification reactions was also evaluated. The arabinoxylans were derivatized by carboxymethylation with sodium monochloroacetate in a 2-propanol alkaline medium using different proportions of alcohol and alkali. The product carboxymethyl xylan was characterized by degree of substitution, FT-IR, DSC, and yield, and showed high degree of substitution, yield and enthalpy of fusion. This work proved the feasibility of producing hemicellulosic derivatives from corn fibers, which excludes the use of extreme conditions of solvents and temperature.

Development of phytocosmeceuticals protective products with promoting adaptation to ultraviolet radiation and induction of melanogenesis

Introduction. Ultraviolet radiation is necessary for a person to function normally, but prolonged exposure to sunlight, including ultraviolet radiation of spectrum C, leads to cancer of the skin. Purpose: the development of phytocosmeceutical agents on a natural basis, reducing the period of adaptation of the human body to ultraviolet radiation, and the search for primary test cultures for testing the developed protective agents. Materials and methods. In the work, the natural mechanism for restoring the vital activity of microorganisms under the short-term exposure to ultraviolet radiation of spectrum C is studied. The possibility of reducing the period of adaptation of the human body to ultraviolet radiation of spectrum C through the use of a protective phytocosmeceutical agent developed by the author is studied. The possibility of using yeast cells as a primary test culture for testing new phytocosmeceutical protective agents has been tested for the first time. Results. The study identified the requirements for protective equipment of the human body against ultraviolet radiation of spectrum C for use in extreme conditions where there are significant violations of the ozone layer. To protect against excessive insolation, a phytocosmeceutical based on ingredients of plant origin was developed, aimed at inducing melanogenesis. The results show that it is acceptable to use Saccharomyces cerevisiae Meyen ex E.C. Hansen as the primary test culture for testing UV-C protective agents. Findings. A natural phytocosmeceutical protective product has been developed that reduces the period of adaptation of the human body to ultraviolet radiation due to the induction of melanogenesis. A convenient object was found that can be used as a primary test culture when testing protective agents against ultraviolet radiation of spectrum C.

Alloying of Fe-Al-Si Alloys by Nickel and Titanium

This paper focuses on one part of the otherwise very complex research of intermetallic compounds based on Fe-Al-Si at the UCT Prague. These materials seem to be suitable candidates for use in extreme conditions (high temperatures, oxidation and sulfidation environment, ...), especially in the aerospace and automotive industries. The aim of this work was to describe the influence of alloying elements - Ni and Ti on phase composition, microstructure, mechanical and oxidative properties, in two specific systems - FeAl35Si5 and FeAl20Si20 (in weight %).