Destructive Reaction Research Articles

Inelastic H + H3+ collision rates and their impact on the determination of the excitation temperature of H3+

Context. In diffuse interstellar clouds, the excitation temperature derived from the lowest levels of H3+ is systematically lower than that derived from H2. The differences may be attributed to the lack of state-specific formation and destruction rates of H3+, which are needed to thermalize the two species. Aims. In this work, we aim to investigate the possible influence of rotational excitation collisions of H3+ with atomic hydrogen on its excitation temperature. Methods. We used a time-independent close-coupling method to calculate the state-to-state rate coefficients, incorporating a very accurate and full-dimensional potential energy surface recently developed for H4+. We take a symmetric top approach to describe a frozen H3+ as an equilateral triangle. Results. We derive rotational excitation collision rate coefficients of H3+ with atomic hydrogen in a temperature range corresponding to diffuse interstellar conditions up to (J, K, ±) = (7, 6, +) and (J, K, ±) = (6, 4, +) for its ortho and para forms. This allows us to obtain a consistent set of collisional excitation rate coefficients and to improve on a previous study that included speculations regarding these contributions. Conclusions. The new state-specific inelastic H3+ + H rate coefficients yield differences of up to 20% in the excitation temperature, and their impact increases with decreasing molecular fraction. We also confirm the impact of chemical state-to-state destruction reactions on the excitation balance of H3+, and that reactive H + H3+ collisions are also needed to account for possible further ortho to para transitions.

Studying The Role Of Cartilago Oligomer Matrix Protein (Comp) In Joint Structure Changes In Osteoarthritis

To study the role of cartilage oligomeric matrix protein in structural changes in joints in patients with osteoarthritis (OA). Material and methods: We observed 50 patients diagnosed with osteoarthritis aged 54.5±4.4 years, of whom 43.8% had radiographic stage 0, 40% had stage I, and 16.2% had stage II. Patients in the main group received treatment aimed at reducing the amount of cartilage oligomeric matrix protein, while patients in the control group received traditional treatment. Results: In addition to clinical improvement and a decrease in the intensity of pain in the knee joint, patients in the main group also had lower levels of SOMP, CRP, and ESR in the blood serum compared to patients in the control group. Conclusions: The treatment method aimed at the dynamics of COMP differs from the traditional one in that it is aimed at suppressing the reactions of cartilage destruction in OA

Control-Oriented Modeling of a Solid Oxide Fuel Cell Affected by Redox Cycling Using a Novel Deep Learning Approach

Abstract A solid oxide fuel cell (SOFC) is a multiphysics system that involves heat transfer, mass transport, and electrochemical reactions to produce electrical power. Reduction and re-oxidation (Redox) cycling is a destructive reaction that can occur during SOFC operation. Redox induces various degradation mechanisms, such as electrode delamination, nickel agglomeration, and microstructural changes, which should be mitigated. The interplay of these mechanisms makes a post-Redox SOFC a nonlinear, time-varying, nonstationary dynamic system. Physics-based modeling of these complexities often leads to computationally expensive equations that are not suitable for the control and diagnostics of SOFCs. Here, a data-driven approach based on dilated convolutions and a self-attention mechanism is introduced to effectively capture the dynamics underlying SOFCs affected by Redox. Controlled Redox cycles are designed to collect appropriate experimental data for developing deep learning models, which are lacking in the current literature. The performance of the proposed model is validated on diverse unseen data sets gathered from different fuel cells and benchmarked against state-of-the-art models, in terms of prediction accuracy and computation complexity. The results indicate 31% accuracy improvement and 27% computation speed enhancement compared to the benchmarks.

H-atom-assisted formation of key radical intermediates in interstellar sugar synthesis

Context. Despite the identification of the smallest sugar molecule, glycolaldehyde (GA), in the interstellar medium (ISM), its mechanism of formation in the ISM is still not fully understood. A more profound understanding of the interstellar chemistry of GA and related molecules could provide insights into whether larger sugar molecules can also form and survive under such conditions. Aims. The primary objectives of this research are to delve into the sugar formation mechanism in the ISM, especially in dark molecular clouds; unravel intricate details of H-atom-mediated reactions involving glyoxal (GO), GA, and ethylene glycol (EG); and identify intermediates playing potential roles in the formation of larger sugars or serving as intermediates in the destruction reaction paths of sugar molecules. Methods. The study utilizes the para-H2 matrix isolation method with infrared (IR) spectroscopic detection and quantum chemical computations to investigate H-atom reactions of GO, GA, and EG at a low temperature. Results. Several radical products were spectroscopically identified that might be key active species in the interstellar formation of larger sugar molecules.

THERMAL TRANSFORMATIONS OF MALTENES AND OILS FROM HEAVY METHANE BASE CRUDES

The paper considers changes of composition of oils and maltenes during thermal cracking process. The oils and maltenes (mixture Oils+Resins) were isolated from crudes from two oil fields: Zyuzeevskoye (Republic of Tatarstan) and Zuunbayanskoye (Mongolia). Both crudes relate to methane type, but differ by content of saturated, aromatic hydrocarbons, resins, asphaltenes and sulfur. Cracking of oils and (O+R) mixtures was carried out at 450 °С for 120 min in isothermal mode. Data on the mass balance of process, composition of gaseous and liquid cracking products were obtained. It was shown the С1-С5 hydrocarbons are predominate in the composition of gaseous cracking products of oils and (O+R) mixtures. Independent of cracking object their content changes in a series: C1 > C2 > C3 > С4-С5. The dynamics of group hydrocarbon composition changes in thermolysates was studied. It was shown the thermal transformations of hydrocarbons steer in the direction of destruction reactions during cracking of oils with high content of saturated hydrocarbons, as it indicated by gaseous products yield. Condensation reactions are dominated during cracking of oils, in composition of which aromatic hydrocarbons are prevail. It was shown the addition of resins into the complex multicomponent mixture of hydrocarbons leads to directivity change of cracking free radical reaction behavior. Differences in structural-group characteristics of average resins molecules reflect not only on the yield of solid and gaseous cracking products of (O+R) mixture, but also affect on the directivity of hydrocarbons thermal transformations. Moreover it is impossible to exclude the effect of differences in the content of saturated and aromatic hydrocarbons in the composition of oils on the components thermal transformations during cracking process of (O+R) mixtures. For citation: Voronetskaya N.G., Pevneva G.S. Thermal transformations of maltenes and oils from heavy methane base crudes. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 59-67. DOI: 10.6060/ivkkt.20246708.4t.

Investigations on the shock wave induced by collapse of a toroidal bubble.

When bubbles collapse near a wall, they typically experience an asymmetric deformation. This collapse leads to the creation of a jet that strikes the bubble interface, causing the formation of a toroidal bubble and the subsequent release of a water-hammer shock. In this study, we present a systematic analysis of the collapse of a toroidal bubble in an open field or adjacent to a flat wall using high-fidelity numerical simulation. To maintain the sharpness of the interface, we employ the interface compression technique and the boundary variation diminishing approach within the two-phase model. Our findings demonstrate that shock waves emitted from the toroidal bubble consistently propagate toward the central axis of the torus, resulting in significant pressure shocks along the axis, similar to the water-hammer shock formed during the collapse of a spherical bubble. In contrast, weak pressure waves are generated in the transverse directions, leading to relatively weaker pressure peaks. Furthermore, the wall-pressure peak induced by the toroidal bubble is approximately three times higher than that induced by the spherical bubble. Based on the directional characteristics of pressure wave propagation from collapsing toroidal bubbles, toroidal-shaped pressure vessels can be designed as buoyancy materials for deep submersibles. This design enables the focused release of energy in a specific direction, effectively minimizing the destructive chain reaction caused by the implosion.

Study of ozone destruction reaction on surfaces

Study of ozone destruction reaction on surfaces

Thermal Degradation Kinetic Study of Expanded Perlite‐Modified Butadiene Rubber Composites

AbstractMineral–rubber composites based on phosphorylated butadiene rubber (PhBR), including pure expanded perlite (EP) and modified phosphorylated expanded perlite (PhEP) as fillers, are developed. The process involves forming PhBR and its composites—EP/PhBR and PhEP/PhBR—through the oxidative chlorophosphorylation (OxCh) reaction. An in‐depth comparative analysis is conducted on the thermal destruction of the PhBR matrix and the EP/PhBR, and PhEP/PhBR composites. The thermogravimetric (TG)/differential thermogravimetry (DTG) analyses reveal three stages of thermal degradation for the PhBR matrix and both composites, highlighting the notable effects of EP and PhEP in the second and third stages of the degradation process. In comparison, the PhEP/PhBR composite exhibits reduced weight loss, the highest integral procedural decomposition temperature (IPDT) value, and a lower Tmax on the DTG curve, compared with the EP/PhBR composite and the PhBR matrix. The mechanism of the thermal destruction reaction and the kinetic parameters Ea and A are calculated using the model‐fitting Coats–Redfern method.

Polarization structure of optical vortices in inclined Laguerre–Gaussian beams passed through a uniaxial crystal

The work shows that in linearly polarized Laguerre–Gaussian beams passing through an anisotropic medium at an angle to the optical axis of the crystal, the distribution of optical vortices is devoid of axial symmetry. It is shown that the trajectories of movement of polarization singularities in the plane of the Laguerre–Gauss beam are different for different cases of input linear polarization at angles γ=±45∘ and there is an exchange of optical vortices, provided that the sign of the topological charge is preserved. It is shown that when the axis of an anisotropic medium is tilted, the movement of optical vortices occurs, accompanied by topological reactions of creation, destruction, or displacement of optical vortices to the periphery of the beam. It is characteristic that at angles of inclination by linear polarization γ=+45∘, topological reactions of creation and annihilation occur, and at angles γ=−45∘, topological reactions of displacement of optical vortices to the periphery of the beam occur.

Математическое моделирование пиролиза резиновых отходов в горизонтальном цилиндрическом реакторе

Recycling of cushioned rubber products is an important environmental and technical-economic issue. Among the various methods of processing such waste, one of the most effective is the pyrolysis process, since it allows us to obtain fuel and energy, and provides the possibility of secondary use of carbon black and metal. Mathematical modeling of this process is necessary to solve problems of optimization and automated control. Thus, the purpose of this study is to simulate the pyrolysis process in a horizontal cylindrical batch reactor, which is currently becoming increasingly widespread. To mathematically describe the process, a model with distributed parameters is used in the form of a two-dimensional thermal conductivity equation and a system of equations of chemical kinetics of polymer thermal destruction reactions. The problem is solved numerically using the finite element method. As a result of the numerical solution of the equations of the mathematical model, non-stationary distributions of temperature and degree of conversion over the cross section of the reactor with non-uniform filling have been obtained. The authors have studied the kinetics of the reaction of polymer thermal destruction in reactors of different diameters. The results obtained can be used to predict the kinetics of material destruction under given reactor heating conditions, which can be useful when we design reactors and automate pyrolysis process control.

Salvia miltiorrhiza Bge. processed with porcine cardiac blood inhibited GLRX5-mediated ferroptosis alleviating cerebral ischemia-reperfusion injury

BackgroundCerebral ischemia-reperfusion injury (CIRI) is a destructive adverse reaction of ischemic stroke, leading to high disability and mortality rates. Salvia miltiorrhiza Bge. (Danshen, DS) processed with porcine cardiac blood (PCB-DS), a characteristic processed product, has promising anti-ischemic effects. However, the underlying mechanism of PCB-DS against CIRI remains unclear. PurposeFerroptosis is demonstrated to be involved in CIRI. The aim of this study was to explore the molecular mechanism underlying PCB-DS inhibited GLRX5-mediated ferroptosis alleviating CIRI, which was different from DS. MethodsQuality evaluation of PCB-DS and DS was conducted by UPLC. Pharmacological activities of PCB-DS and DS against CIRI were compared using neurobehavioral scores, infarct volume, proinflammatory factors, and pathological examinations. Proteomics was employed to explore the potential specific mechanism of PCB-DS against CIRI, which was different from DS. Based on the differential protein GLRX5, ferroptosis-related iron, GSH, MDA, SOD, ROS, liperfluo, and mitochondrial morphology were analyzed. Then, the proteins of GLRX5-mediated iron-starvation response and SLC7A11/GPX4 were analyzed. Finally, OGD/R-induced SH-SY5Y cells upon GLRX5 silencing were constructed to demonstrate that PCB-DS improved CIRI by GLRX5-mediated ferroptosis. ResultsPCB-DS better alleviated CIRI through decreasing neurological score, reducing the infarct volume, and suppressing the release of inflammatory cytokines than DS. Proteomics suggested that PCB-DS may ameliorate CIRI by inhibiting GLRX5-mediated ferroptosis, which was different from DS. PCB-DS reversed the abnormal mitochondrial morphology, iron, GSH, MDA, SOD, ROS, and liperfluo to inhibit ferroptosis in vitro and in vivo. PCB-DS directly activated GLRX5 suppressing the iron-starvation response and downregulated the SLC7A11/GPX4 signaling pathway to inhibit ferroptosis. Finally, silencing GLRX5 activated the iron-starvation response in SH-SY5Y cells and PCB-DS unimproved OGD/R injury upon GLRX5 silencing. ConclusionDifferent from DS, PCB-DS suppressed ferroptosis to alleviate CIRI through inhibiting GLRX5-mediated iron-starvation response. These findings give a comprehensive understanding of the molecular mechanism underlying the effect of PCB-DS against CIRI and provide evidence to assess the product in clinical studies.

Squeezing MHD Flow of Sodium Alginate-Based Casson Hybrid Nanofluid with Soret and Dufour Effects

Ultrahigh-performance cooling is one of the essential requirements in the industrial technology. Hence, the new heat transfer fluid, hybrid nanofluid is introduced to increase the thermal conductivity of fluid and investigated with various physical parameters. The unsteady magnetohydrodynamics (MHD) flow of Casson hybrid nanofluid through two surfaces in a permeable medium with chemical reaction are explored. The hybrid nanoparticles of Alumina and Copper is dispersed in the base fluid of sodium alginate . The discretize equations are solved using similarity transformation and Keller-box methods. The comparison of the current results with the published results for validation is conducted and discovered in proper agreement. The impacts of squeeze, magnetic, porous media, chemical reaction, heat sink/source, and Soret and Dufour on behaviour and physical quantities of flow are discussed. The graphical results show the squeeze of two surfaces accelerates the fluid velocity near the upper plate region. Further, the velocity slowing down when and increases, and it elevates as and rises in the middle of channel. The increment of heat transfer rate and temperature of fluid is shown for increasing Ec, y and Du, and the opposite behaviour is discovered with raise in. The fluid concentration decreases and the mass transfer rate enhances for rising Sr. The concentration enhance and rate of mass transfer reduce with the constructive chemical reaction, whereas contrary effects is shown for destructive chemical reaction.

Radiation Absorption and Chemical Reaction Effects on MHD Flow Through Porous Medium Past an Exponentially Accelerated Inclined Plate with Variable Temperature

The present paper investigates an unsteady MHD free convection flow heat and mass transfer past an exponentially accelerated inclined plate embedded in a saturated porous medium with uniform permeability, variable temperature and concentration has been studies. The effect of angle of inclination on the flow phenomena in the presence of heat source or sink and destructive reaction. The governing partial differential equations are solved by using regular perturbation technique. The present study has an immediate application in understanding the drag experienced at the heated or cooled and inclined surfaces in a seepage flow.

In-situ texturing hollow carbon host anchored with Fe single atoms accelerating solid-phase redox for Li-Se batteries

Se-based cathodes have caught tremendous attention owing to their comparable volumetric capacity and better electronic conductivity to S cathodes. However, its low utilization ratio and sluggish redox kinetics due to the high reaction barrier of solid-phase transformation from Se to Li2Se limit its practical application. Herein, an in-situ texturing hollow carbon host by gas–solid interface reaction anchored with Fe single-atomic catalyst is designed and prepared for advanced Li-Se batteries. This Se host presents high pore volume of 1.49 cm3 g−1, Fe single atom content of 1.53 wt%, and its specific structure protects single-atomic catalyst from the destructive reaction environment, thus balancing catalytic activity and durability. After Se loading by reduction of H2SeO3, this homogenous Se-based cathode delivers a superior rate capacity of 431.3 mA h g−1 at 4C, and great discharge capacity of 301.8 mA h g−1 after 1000 cycles at 10C, with high Li-ion diffusion coefficient and capacitance-contributed ratio. The distribution of relaxation times analysis verifies solid-phase transformation mechanism of this cathode and density functional theory calculations confirm the adsorption and bidirectionally catalysis effect of Fe single-atomic catalyst. This work provides a new strategy to prepare high-efficient Se cathode associated with non-noble metal single atoms for high-performance Li-Se batteries.

Viscous dissipation and Joule heating effects of Carreau nanofluid axisymmetric flow past unsteady radially stretching porous disk

In this piece of communication, a theoretical investigation of two dimensional boundary layer flow of Magnetohydrodynamics (MHD) Carreau nanofluid axisymmetric flow past unsteady radially stretching porous disk is made. The investigation includes the effects of viscous dissipation, Joule heating, thermal radiation, suction/injection, Darcy–Forchheimer porosity model and binary chemical reaction with activation energy, etc. To examine the impacts of the aforementioned effects, the conservation laws are formulated with strongly nonlinear partial differential equations (PDEs), which are then transformed into a system of initial value problems (IVPs) using appropriate similarity transformations and techniques. The 5th order Runge–Kutta with the shooting technique is used to find numerical solutions aided by Python programming with built in program “fsolve”. The method is validated with other published articles under common assumptions and it agrees nicely. The impacts of the pertinent parameters on velocity, temperature, concentration, skin friction coefficient and the rates of mass and heat transfers with in the flow regime are displayed using graphs and tables. The main outcomes include the motivation of local Nusselt and Sherwood numbers for shear thickening (n=1.5) than shear thinning (n=0.5) cases of the Carreau nanofluid. The momentum boundary layer of the Carreau nanofluid gets thinner with an increase in Forchheimer number, unsteady and suction parameters. A dual nature is observed for concentration of the Carreau nanofluid with a rise in Eckert number, i.e increasing in concentration around the wall and decreasing far away from the wall. The rise in destructive and constructive chemical reaction parameters disperse and accumulate the concentration of the system, respectively.

Kinetics study of total organic carbon destruction during supercritical water gasification of glucose

AbstractThe kinetics of total organic carbon (TOC) destruction during supercritical water gasification (SCWG) of glucose were studied at 400–500°C and 25 MPa in a 600 mL batch reactor. Both TOC and water concentrations are critical for the conversion of TOC in supercritical water, especially at longer residence times. Initially, it was assumed that the TOC destruction reaction followed first‐order kinetics ignoring the water concentration. However, experimental results showed that the feed‐to‐water ratio had a significant effect on TOC decomposition. Considering the water concentration in the reaction, the reaction orders of TOC (2.35) and water (1.45) were calculated using nonlinear regression analysis (the Runge‐Kutta method). The estimated pre‐exponential factor (k’) and activation energy (E) were calculated to be 8.1 ± 2/min and 90.37 ± 9.38 kJ/mol respectively.

A spatiotemporal “bulk erosion” mode in selective laser melted magnesium alloys and the resulting adverse cell & tissue responses

Selective laser melting (SLM) has attracted great attention in the fabrication of magnesium-based biodegradable implants. However, current SLMed magnesium alloys are generally suffered from rapid corrosion, which is deadly detrimental to their use. Herein, we thoroughly revealed why they are so vulnerable to corrosion through a typical SLMed AZ91D material model. An abnormally spatiotemporal “bulk erosion” mechanism was found, not the well-known “surface corrosion” mode of traditionally plastic-deformed alloys. The unique microstructure derived from SLM possesses high chemical reactivity, which is favorable for interactional attacks of fast fluid penetration, severe local corrosion and intensive micro-galvanic corrosion. Thus, it brings two orders of magnitude in corrosion rates compared with its plastic-deformed counterparts. In vitro, such fast-corrosion induced apparent cytotoxicity, cell damage, and further apoptosis to rat and mouse derived mesenchymal stem cells. In vivo, the material disintegrates into small pieces in a short period, and results in unexpected bone destruction and long-lasting foreign body reactions in Sprague Dawley rats. Close attention should be paid to this issue before SLMed Mg-based implants being applied in patients.

Protective effects of ectoine on articular chondrocytes and cartilage in rats for treating osteoarthritis.

Osteoarthritis (OA) is a chronic degenerative disease that primarily includes articular cartilage destruction and inflammatory reactions, and effective treatments for this disease are still lacking. The present study aimed to explore the protective effects of ectoine, a compatible solute found in nature, on chondrocytes in rats and its possible application in OA treatment. In the in vitro studies, the morphology of the chondrocytes after trypsin digestion for 2 min and the viability of the chondrocytes at 50°C were observed after ectoine treatment. The reactive oxygen species (ROS) levels in chondrocytes pretreated with ectoine and post-stimulated with H2O2 were detected using an ROS assay. Chondrocytes were pretreated with ectoine before IL-1β stimulation. RT‒qPCR was used to measure the mRNA levels of cyclooxygenase-2 (COX-2), metallomatrix proteinase-3, -9 (MMP-3, -9), and collagen type II alpha 1 (Col2A1). In addition, immunofluorescence was used to assess the expression of type II collagen. The in vivo effect of ectoine was evaluated in a rat OA model induced by the modified Hulth method. The findings revealed that ectoine significantly increased the trypsin tolerance of chondrocytes, maintained the viability of the chondrocytes at 50°C, and improved their resistance to oxidation. Compared with IL-1β treatment alone, ectoine pretreatment significantly reduced COX-2, MMP-3, and MMP-9 expression and maintained type II collagen synthesis in chondrocytes. In vivo, the cartilage of ectoine-treated rats exhibited less degeneration and lower Osteoarthritis Research Society International (OARSI) scores. The results of this study suggest that ectoine exerts protective effects on chondrocytes and cartilage and can, therefore, be used as a potential therapeutic agent in the treatment of OA.

Can astronomical observations be used to constrain crucial chemical reactions? The methoxy case. SOLIS XVIII

ABSTRACT To understand the origin of interstellar molecules we rely on astrochemical models, the gas-phase networks of which contain ≥7000 reactions. However, just a tiny fraction of them have parameters derived in laboratory experiments. Theoretical quantum mechanical (QM) calculations can also provide this information. Unfortunately, sometimes theoretical predictions and experimental values disagree, as is the case for the paradigmatic reaction CH3OH + OH → CH3O + H2O. Both laboratory experiments and QM calculations found an unexpected increase in the rate coefficients with decreasing temperature. However, experimental and theoretical estimates of the rate coefficients diverge by up to two orders of magnitude at the low temperatures of interest in interstellar chemistry. This work aims to test whether astronomical observations can help untangle this confusing situation. To this end, we first carried out new QM calculations to derive the rate coefficients of the major destruction reaction of the methoxy radical, CH3O + H, and then we compared astronomical observations from the IRAM/NOEMA Large Programme SOLIS with astrochemical model predictions. Our new rate coefficient for the CH3O + H reaction is 5–10 times larger than that in the astrochemical data base KIDA in the 10–100 K range. When including the new methoxy destruction rate coefficients, the comparison between observations and model predictions favours the rate coefficients of the CH3OH + OH reaction from QM calculations. We conclude that QM calculations are an important alternative to laboratory experiments when it comes to the harsh conditions of interstellar objects and that astronomical observations can be used to constraint the rate coefficients of relevant reactions.

Huge osteoma in the frontoparietal bone caused by trauma from 18 years ago: a case report

BackgroundOsteomas are asymptomatic, benign tumors and are diagnosed accidentally by radiological investigations conducted for other reasons. In some cases, they may cause aesthetic or functional symptoms by affecting nearby organs. The cause of osteoma is still dialectical. Many theories suggest that inflammation, trauma, or congenital causes are behind its formation. In our case, the patient presented with a symptomatic and huge osteoma in the frontoparietal bone caused by trauma from 18 years ago.Case presentationA 24-year-old Syrian woman came to our hospital complaining of headaches, syncope episodes, blurred vision, and tumor formation in the frontoparietal region. The medical and surgical histories of the patient revealed appendectomy and head trauma when she was 6 years old in a traffic accident. Radiological investigations showed thickness in the space between the two bone plates in the left frontoparietal region, which reached the orbital roof without cortical destruction or periosteum reaction; the tumor size was 5 cm × 5 cm. A surgical excision was indicated. Under general anesthesia, the surgery was done for the tumor excision. The histopathology examination emphasized the diagnosis of osteoma. The follow-up for 7 months was uneventful.ConclusionThis paper highlights the importance of focusing on the medical history of patients with osteoma in an attempt to explain the reasons for its occurrence. It stresses the need to put osteoma within the differential diagnoses of skull tumors.