Explosive Events Research Articles

Self-Propulsion by Directed Explosive Emulsification.

An active droplet system, programmed to repeatedly move autonomously at a specific velocity in a well-defined direction, is demonstrated. Coulombic energy is stored in oversaturated interfacial assemblies of charged nanoparticle-surfactants by an applied DC electric field and can be released on demand. Spontaneous emulsification is suppressed by an increase in the stiffness of the oversaturated assemblies. Rapidly removing the field releases the stored energy in an explosive event that propels the droplet, where thousands of charged microdroplets are ballistically ejected from the surface of the parent droplet. The ejection is made directional by a symmetry breaking of the interfacial assembly, and the combined interaction force of the microdroplet plume on one side of the droplet propels the droplet distances tens of times its size, making the droplet active. The propulsion is autonomous, repeatable, and agnostic to the chemical composition of the nanoparticles. The symmetry-breaking in the nanoparticle assembly controls the microdroplet velocity and direction of propulsion. This mechanism of droplet propulsion will advance soft micro-robotics, establishes a new type of active matter, and introduces new vehicles for compartmentalized delivery.

Dynamic Response Characteristics of Composite Concrete Structures Subjected to Reactive Jet Impact

Composite concrete structures, commonly found in urban infrastructures, such as highways and runways, are pivotal research object in the protection field. To study the dynamic response of composite concrete structures subjected to reactive jet penetration coupled with an explosive effect, a full-scale damage experiment of composite structures under the action of 150 mm caliber shaped charges was performed, to derive the dynamic damage modes of different concrete thicknesses under the combined kinetic and chemical energy damage effects. The results indicated that under aluminum jet penetration, concrete layers exhibited minor funnel craters and penetration holes. However, concrete layers displayed a variety of damage modes, including central penetration holes, funnel craters, bulges, and radial/circumferential cracks when subjected to the PTFE/Al jet. The area of the funnel crater expanded as the thickness of the concrete increased, while the height of the bulge and the number of radial cracks decreased. The diameter of penetration holes increased by 76.9% and the area of funnel crater increased by 578% in comparison to Al jet penetration damage. A modified-RHT concrete model that reflected concrete tensile failure was established, utilizing AUTODYN. Segmented numerical simulations of damage behavior were performed using the FEM-SPH algorithm and a restart approach combined with reactive jet characteristics. The spatial distribution characteristic of the reactive jet and the relationship between kinetic penetration and explosion-enhanced damage were obtained by the simulation, which showed good concordance with the experimental results. This study provides important reference data and a theoretical basis for the design of composite concrete structures to resist penetration and explosion.

DESTRUCTION OF ROCKS BY EXPLOSION DURING OIL TRANSPORTATION

When oil and gas wells are ready for operation, when drilling is carried out at the bottom of the well to establish contact with the formation, it is considered that the degree of crushing of the rocks is proportional to the speed of application of the load. As a result of the stresses created by them, the degree of fragmentation is higher. In the article, it is proposed to take into account the quality of crushing of the necessary rock by using some empirical coefficients in the calculation formulas. The dynamics of the rock dispersion process is studied on the basis of the hydrodynamic hypothesis. Here, the solution of the system of differential equations is given based on the fundamental laws of conservation of mass, energy and momentum. Based on the strength properties of mountain rocks, broken lines are found in the continuum of the whole environment, which determines the final effect of rock crushing. However, the accepted assumptions about the incompressibility of the rock and the transfer of the explosive impulse to the immediate environment significantly reduce the practical value of the results. It should be noted that in the immediate area directly adjacent to the load, the mountain rock is under uneven volume compression. In this case, the largest tangential stresses occur mainly in planes oriented at an angle of 450 to the radial direction. Thanks to this, a system of spiral sliding lines breaks the rock into small blocks. Outside this zone, a system of radial cracks is formed as a result of the expansion of the massif. When the pressure in the gas cavity decreases and the mass moves back in the direction of the load, tangential cracks appear. The combination of the volume compression zone and the reach zone constitutes the controlled crushing area. When the compression wave reaches the bare surface, it becomes a stress wave. As this wave travels from the surface to the load, it forms a system of jump cracks. The high explosive effect of explosive gases with sufficient explosion energy causes the release of such shattered rock. Obviously, this concept is very important for the development of the theory of explosive disintegration of mountain rocks. Because there is no unequivocal relationship between the nature of the dissolution of the rock and the acoustic hardness. One of the first to clearly describe the mechanism of shock wave formation and its transformation into a more explosive and seismic wave when detonation reaches the boundary of the charge cavity. In rocks, shock waves are formed during the entire time of expansion of the gas cavity. It explains in detail the mechanism of cracking phenomena by considering the cracks as a source of multiple reflections of the stress wave. Keywords: rock strength, constant material, scale effect, rocks, destruction probability, fractured, robustness theory, microcrack, mineral, experience constant, density of defects, displacement, compression.

The Paleoecological Environment during the Ediacaran–Cambrian Transition in Central Guizhou Province, China: Evidence from Zn Isotopes

During the Ediacaran–Cambrian transition, a series of stratal continuous and well-preserved siliceous rock and phosphorite assemblages developed in Qingzhen, Guizhou Province, China, facilitating research on the biological evolution, marine chemistry, and palaeoecological environment of this period. Therefore, we investigated the paleontology, trace and rare earth elements, total organic carbon, total sulfur content, and Zn isotopes of the phosphorus-bearing rock series in the Taozichong Formation of the Cambrian period in Qingzhen. Geochemical analysis reveals that the sedimentary rocks in this area were formed in the oxygen-rich seawater environment and were not affected by high-temperature hydrothermal activity. The upwelling ocean current provided abundant rare earth elements and other nutrient elements, as well as conditions for the prosperity of biota in Qingzhen. In addition, the δ66Zn value (−0.21‰–0.41‰ range and 0.17‰ mean) in the Qingzhen phosphorous rock series was much lower than that in seawater, indicating a strong level of biological productivity. The variation trend of δ13C, δ18O, and δ66Zn exhibited four stages and three obvious drift events. The results suggest that climate change during this period led to the intermittent flourishing and extinction of organisms, which triggered the negative drift of δ13C and δ18O in the ocean, resulting in a coordinated response of δ66Zn. The unique ecological environment of the Taozichong Formation in Qingzhen also provides favorable conditions for the population continuation of Ediacaran-type benthic soft-bodied metazoon dominated by discoid fossils, Shaanxilithes, worm fossils, and sponge fossils in the Cambrian strata, as well as participation in the global biological explosion events. The study area provides new insights for rebuilding the global Ediacaran–Cambrian ecosystem during the transition period.

Effects of steam explosion on raspberry leaf structure and the release of water-soluble nutrients and phenolics

Raspberry leaves were subjected to steam explosion at 0.5 and 1.0 MPa for 60–120 s, aiming to disrupt their physical and chemical structure and, consequently, promote the release of phenolic compounds into the leaf aqueous infusion. Under optimal condition of 1.0 MPa for 60 s, steam explosion led to a notable 23 % increase in total phenolic content, a 29 % elevation in ABTS radical scavenging capacity, and a 13 % rise in DPPH radical scavenging capacity of the aqueous infusion. Utilizing UHPLC-Q-TOF-MS/MS and UHPLC-QE-MS/MS techniques, respectively, a total of 39 phenolic compounds were identified from raspberry leaves, and the changes in the contents of the most important 11 species were analyzed following steam explosion. Through correlation analysis and considering the content of each phenolic compound, it was inferred that the heightened antioxidant capacity of the aqueous infusion primarily stemmed from a substantial increase in the release of ellagic acid after steam explosion.

Quantitative risk estimation of CNG station by using fuzzy bayesian networks and consequence modeling

As one of the potential explosions and inflammation, compressed natural gas (CNG) stations in urban areas cause irreparable losses and casualties. Estimating risk assessment in gas stress based on coherent uses can reduce accidents in urban areas. The purpose of the present study was to estimate a small risk estimation at one of the CNG multipurpose stations, LPG, using combined models of the Fuzzy Bayesian Network, Bow-tie Diagram, and consequence modeling. This study was conducted based on the basic and 25 intermediate events. This study formed a seven-person safety team to identify the primary events and build the Bow-tie diagram. Then, because of the lack of a proper database, fuzzy theory was used to determine the probability of significant events. Bayesian networks were drawn based on the Bow-tie model using GeNLe software. Finally, the main events of the two Bow-tie, Bayesian network modeling, and risk estimation were performed with the help of PHAST/SAFETI (V8.22). The geographical information system software was used to zone the explosion effects. The Risk assessment result showed that the social risks and the Bayesian network model are more than Bow-tie, and the Bow-tie diagram is unacceptable. Therefore, using incompatible land uses in the vicinity of the CNG stations gives rise to the effects of accident scenarios in particular residential and administrative land uses, which decision-makers and city managers should consider. Based on the findings of this study, the obtained results can be utilized to implement effective control measures. These measures encompass devising a response plan tailored to address specific emergency conditions and conducting comprehensive training programs for the individuals and residents residing within the study area.

Black holes and foliation-dependent physics

In theories where physics depends on a global foliation of space-time, a black hole’s horizon is surrounded by an “eternity skin”: a pile-up of spacelike leaves that in the far-out region cover all times from the start of collapse to future eternity. Any future foliation-dependent change in the laws of physics would be enacted in this region and affect the last stages of collapse toward black hole formation. We show how in some cases the black hole never forms but, rather, bounces into an explosive event. There is also a nonlocal transfer of energy between the asymptotic Universe and the formed black hole precursor, so that the back hole (if formed) or the exploding star (otherwise) will have a different mass from what was initially thrown in. These last matters are generic to nonlocal theories and can be traced to the breakdown of the local Hamiltonian constraint. Published by the American Physical Society 2024

Complex facies architecture of unusual pyroclastic density current deposits at the Rincón de la Vieja Volcano, Costa Rica

Pyroclastic Density Currents (PDCs) constitute a complex, multiphase, and multiscale volcanic process generated in a wide spectrum of eruptive scenarios and being among the most deadly and destructive volcanic hazards. Over the north flank of the Rincón de la Vieja Volcano, Costa Rica, previous works identified PDC deposits related to the plinian Río Blanco eruption, which is the largest Holocene explosive event recorded at this volcano. However, so far, there have been no in-depth studies aimed at understanding the eruptive style, and dynamics of the parental PDCs. This work presents, for the first time, a detailed facies analysis and architecture reconstruction (plus a geochemical characterization and novel C14 age determinations) of these outstanding deposits. The presence of cauliflower bombs, juvenile mega-blocks, scorias, and pumices, coupled with the scarcity of accidental and/or accessory lithics, is interpreted here as evidence of an unusual eruptive style. We propose that the Río Blanco eruption was a single complex eruption consisting of two successive phases, each involving the drainage of distinct magma batches. The PDCs were related to the sudden spill out of a lava-pool (Arenal-type PDC), during the collapse of an ultraproximal pyroclastic cone that was built in an initial plinian phase. The collapse of this ultraproximal cone produced a leading-edge pumice-rich PDC, which increased its mobility through fragmentation-induced fluidization. This leading edge PDC was followed by successive high concentrated, mafic, modified granular flow pulses derived from the lava-pool spill out. These modified granular flows were highly channelized in proximal zones, but when they reached the main break in slope, the basal underflow froze en masse while its upper, more diluted part started to decouple and move in a more unconfined manner. After the decoupling, the material feeding towards the basal zone of the surviving current produced a new underflow by rapid suspension sedimentation (“surge-derived pyroclastic flows”). Finally, our results indicate that the generation of Arenal-type PDCs is an underestimated scenario that should be considered in future short-term hazard and risk assessments at the Rincón de la Vieja Volcano, as well as in many other stratovolcanoes worldwide.

Explosive blast loading effect on transient mechanical responses of aircraft panels with curvilinear fibers: 3D elasticity approach

In the present paper, for the first time, the dynamic loading effect on transient bending and stress distributions of aircraft nanocomposite sandwich panels including curvilinear fibers are presented and explained. Face sheets of the panel contain curvilinear fibers with an orientation angle varies linearly with respect to the horizontal coordinate. The core layer is made of polymer matrix reinforced by graphene platelets (GPLs) with uniform and random orientation distribution. 3-D elasticity theory is used to formulate the transient problem of the panel. The model of the panel is so general to include different time-dependent loads, especially explosive ones. A three-dimensional layerwise-differential quadrature method (LW-DQM) together with a non-uniform rational B-spline-based multi-step time integration scheme is employed to investigate the transient responses of the sandwich panel with variable stiffness composite laminated face sheets (VSCL-FS) and graphene platelets reinforced porous core (GPLR-PC) under dynamic loading. The convergence behavior of the method is examined numerically and to assure its accuracy, the results in the limit cases are compared with those available in the literature. Finally, through the parametric studies, the effects of core porosity distribution and amounts, GPLs weight fraction and boundary conditions on the transient responses of the sandwich panel with VSCL-FS and GPLR-PC subjected to explosive blast loading are investigated. The results show that the addition of GPLs to the core layer decreases the transverse displacement but increases the peak values of the stress components. Also, the core porosity increases the transverse displacement and the stress components. However, it has not significant effect on the period of oscillation of the field variables under explosive blast loading. On the other hand, the curvature of the fibers does not considerable effect on the plate response and on the period of oscillation of the field variables under explosive blast loading

Hydrogen safety effect calculation (dispersion and thermal radiation effects) for determination of siting and safe distance

AbstractThe main aim of this study was to evaluate the potential effect of dispersion, thermal radiation, and explosion from a poly‐bed pressure swing adsorption (PSA) unit with its surrounding facility to determine its safety distance. Thus, the Shell FRED (fire, release, explosion, and dispersion) consequence modeling was used to predict the impact of a release scenario and assist in designing, developing, and maintaining safe operation. This study was intended to calculate dispersion contours to 50% lower flammable limit (LFL) and 100% LFL, thermal impacts of radiation flux levels of 4, 5, 12.5, and 37.5 kW/m2 at a distance, and including explosive effects of 0.1, 0.2, and 0.35 bar to the chosen target. Based on the findings, it was found that, to avoid exposure to heat radiation of 12.5 kW/m2 from the PSA unit, equipment should be located at a minimum distance of 20.84 m. Meanwhile, process modules and buildings must be located at a minimum distance of 13.8 m. The explosive nature of hydrogen makes on‐site handling and storage more challenging than fossil fuels. The findings of this study will have important implications for the future handling and storage of hydrogen as a potential fuel.

Comparative analysis of blast load transfer and structural damage in multi-cabin structures during air and underwater explosions

This study presents comprehensive experimental and numerical findings regarding the impact of the fluid medium on blast load transfer and structural damage mechanisms in multi-cabin structures subjected to air and underwater explosions. The experiments demonstrated that the structure primarily underwent a comprehensive dynamic response during an air explosion. In contrast, underwater explosions induced severe localized damage, with fluid properties significantly influencing the shockwave intensity. The observed plastic deformation, shear tearing of the structure, and shock wave characteristics in the experiment were successfully predicted through numerical simulations. Additionally, the numerical simulation unveiled distinct mechanisms of pressure changes in the cabin, attributing air and underwater explosions to transmitted pressure waves and compression shocks of the outer plate, respectively. The high-intensity shock waves generated by underwater explosions and bubble loads sequentially impacted the structure, resulting in more pronounced structural damage compared to the weaker shock wave effect of an air explosion. This study provides valuable insights for comprehending and predicting the response of multi-cabin structures in diverse explosion scenarios.

Exploiting PlanetScope Imagery for Volcanic Deposits Mapping

During explosive eruptions, tephra fallout represents one of the main volcanic hazards and can be extremely dangerous for air traffic, infrastructures, and human health. Here, we present a new technique aimed at identifying the area covered by tephra after an explosive event, based on processing PlanetScope imagery. We estimate the mean reflectance values of the visible (RGB) and near infrared (NIR) bands, analyzing pre- and post-eruptive data in specific areas and introducing a new index, which we call the ‘Tephra Fallout Index (TFI)’. We use the Google Earth Engine computing platform and define a threshold for the TFI of different eruptive events to distinguish the areas affected by the tephra fallout and quantify the surface coverage density. We apply our technique to the eruptive events occurring in 2021 at Mt. Etna (Italy), which mainly involved the eastern flank of the volcano, sometimes two or three times within a day, making field surveys difficult. Whenever possible, we compare our results with field data and find an optimal match. This work could have important implications for the identification and quantification of short-term volcanic hazard assessments in near real-time during a volcanic eruption, but also for the mapping of other hazardous events worldwide.

DNA quality and quantity in adipose tissue: a comparison of the effects of bomb explosion

BACKGROUND Adipose tissue is often overlooked in DNA testing due to misconceptions about its DNA content. However, its shock-absorbing qualities may be useful for high-pressure scenarios like bomb blasts. This study aimed to evaluate DNA quality and quantity in adipose tissue affected by blasts compared to that in unaffected tissue.
 METHODS 10 adipose tissue samples were taken from regions near and far from the blast, representing the blast-exposed and non-blast-exposed groups. The adipose tissue was stored at a low temperature for 5 days, after which an organic extraction method was applied. The purity of the DNA extract was assessed using a NanoDrop spectrophotometer, and its integrity was evaluated using 0.8% concentration gel electrophoresis at 60 V for 90 min. DNA typing was conducted using the GlobalFiler™ kit, and DNA quantity was determined with the Quantifiler™ Trio DNA Quantification kit.
 RESULTS Of 20 DNA extracts from adipose tissue, all samples demonstrated purity, integrity, and complete typing results. Adequate integrity was found in 90% of samples in both groups. A 50% incidence of allele shifting was observed at the D7S820 locus within the blast-exposed group.
 CONCLUSIONS DNA from blast-exposed adipose tissue exhibited no significant quality or quantity differences from non-blast-exposed tissue. This suggested adipose tissue’s potential as an alternative DNA source in a bomb explosion.

Experimental study on protection of prestressed concrete box girder under vehicle explosion of bridge deck

AbstractThis paper presents a study on the explosion protection of prestressed concrete box girder, which is a commonly used in concrete bridges. The explosion protection tests of four prestressed box beams were designed with 1:5 scale. In order to evaluate the explosion performance of different protective layers, steel plate, ultra‐high‐performance concrete (UHPC) layer, and composite protective layer were used to protect the box girder. The experimental results revealed that under the effect of deck explosion, local penetrating failure occurred in the top plate of the box girder, which exhibited characteristics of punching failure. The web and bottom plate of the box girder as a whole exhibited bending characteristic. Compared with the unprotected box girder, the damage of the top plate of the protected box girder was less severe, whereas the damage of the bottom plate was greater. In working conditions 2–4, the UHPC protective box girder suffered less damage to the top plate, whereas the other protective box girders suffered more. The explosion dynamic responses of the box girder were compared, and the influences of different protective layers on the explosion dynamic response of box girder were studied. Based on the box girder damage, the protective efficiency of each protective layer under near‐explosion was studied. Based on the explosion tests, three‐dimensional numerical analysis model of box girder explosion was established. The accuracy of the numerical simulations of the box girder explosion were verified by comparing with the experimental failure data. Through the numerical results, the explosive energy dissipation capacity of different protective materials was compared and analyzed. Finally, based on the dynamic response of the box girder under different working conditions, the sensitivity of the protective layer to the dynamic responses of the box girder were studied. The analysis showed that the UHPC layer was sensitive to the change of prestress and explosion damage area of the box girder but had little influence on the rebars stress and the overall response of the box girder.

A study on the damage characteristics of glass under the combined effects of explosion and high temperature: An analysis using peridynamics

Statistics from explosion incidents indicate that the primary cause of casualties in such events is often flying glass fragments, frequently accompanied by fires. This study investigates the damage mechanisms of glass under the combined effects of explosions and high temperatures, examining its dynamic response to blast loads. We simulate the dynamic response of glass under blast impact at both ambient and high temperatures using the peridynamics (PD) algorithm. The results show that the glass edges experience the highest stress, leading to the initial formation of cracks in these areas under various conditions. Additionally, increased stress causes more pulverization of fragments at the edge. Comparative analysis of the crack initiation process under different conditions reveals significant behavioral differences in glass with varying load-resistance capabilities when exposed to impact loads. At high temperatures, crack development is predominantly influenced by the impact load, diminishing the effect of stress transfer on the expansion of glass cracks. The findings of this research provide theoretical insights into the destructive mechanisms of glass under the combined influence of explosions and high temperatures, contributing to the design of blast-resistant glass.

Geochronology and geochemistry of the Gréixer rhyolitic caldera complex: Implications on Permo-Carboniferous magmatism (South-Central Pyrenees, NE Spain)

The Gréixer Rhyolitic Complex is one of the most important manifestations of the post-Variscan Permo-Carboniferous volcanism of the Catalan Pyrenees. This volcanic complex is represented by a > 800 m thick, > 12 km wide, intra-caldera succession, mostly composed of strongly-welded, lava-like rheomorphic rhyolitic pyroclastic rocks. Previous studies have attributed a Lower Permian age to this caldera complex and interpreted it as having resulted from the gravitational collapse of a central volcanic edifice after a large-volume explosive event, mostly represented by widespread extra-caldera pyroclastic deposits (the Castellar de n'Hug Ignimbritic Member), which was radially emplaced from the caldera structure. However, new stratigraphic, structural, geochemical, and geochronological data reveal that this co-genetic relationship between the inferred intra- and extra-caldera deposits does not exist. On the contrary, each of these two successions of pyroclastic deposits resulted from a different volcanic event, which had occurred within a time span of 15 Ma. Moreover, the geochemical signature of these volcanic rocks shows a different magma source for each case, with a clear crustal origin for the Gréixer Rhyolitic Complex and a mixed mantle-crustal origin for the Castellar de n'Hug Ignimbrite Member. The apparent stratigraphic correlation between both successions is the result of the Alpine tectonics, which put together different late and post-Variscan Permo-Carboniferous rocks that had originated in different areas and at different times.

Geological evidence of extensive N-fixation by volcanic lightning during very large explosive eruptions

Most of the nitrogen (N) accessible for life is trapped in dinitrogen (N2), the most stable atmospheric molecule. In order to be metabolized by living organisms, N2 has to be converted into biologically assimilable forms, so-called fixed N. Nowadays, nearly all the N-fixation is achieved through biological and anthropogenic processes. However, in early prebiotic environments of the Earth, N-fixation must have occurred via natural abiotic processes. One of the most invoked processes is electrical discharges, including from thunderstorms and lightning associated with volcanic eruptions. Despite the frequent occurrence of volcanic lightning during explosive eruptions and convincing laboratory experimentation, no evidence of substantial N-fixation has been found in any geological archive. Here, we report on the discovery of a significant amount of nitrate in volcanic deposits from Neogene caldera-forming eruptions, which are well correlated with the concentrations of species directly emitted by volcanoes (sulfur, chlorine). The multi-isotopic composition (δ18O, Δ17O) of the nitrates reveals that they originate from the atmospheric oxidation of nitrogen oxides formed by volcanic lightning. According to these first geological volcanic nitrate archive, we estimate that, on average, about 60 Tg of N can be fixed during a large explosive event. Our findings hint at a unique role potentially played by subaerial explosive eruptions in supplying essential ingredients for the emergence of life on Earth.

Community Relations Pt. Pertamina Pasca Meledaknya Depo Pertamina Plumpang

This research aims to analyze the dynamics of the relationship between the community and PT. Pertamina following the explosion at the Pertamina Plumpang Depot. The study employs a qualitative approach, collecting data through observation, media monitoring, and company documents. The results indicate that the explosion event has significantly impacted the relationship between PT. Pertamina and the surrounding community. Concerns, uncertainty, and a sense of insecurity among the public have posed various challenges in maintaining a harmonious relationship. Despite PT. Pertamina's efforts to improve its image and address the negative impacts, there remains an expansion of perceptual gaps between the company and the community. The implications of these findings can serve as a foundation for PT. Pertamina and relevant stakeholders in designing more effective communication strategies to strengthen post-incident community relations.

Mid-Miocene silicic explosive volcanism of the Tokaj Mts., eastern-central Europe: Eruption chronology, geochemical fingerprints and petrogenesis

The Tokaj Mts. volcanism occurred in a thinning continental lithosphere regime at the final stage of the subduction process. Using high-precision zircon U-Pb dating, four major explosive eruption events were distinguished. Among them the 13.1 Ma Sátoraljaújhely and the 12.0 Ma Szerencs eruptions could have yielded large amount of volcanic material (possibly > 100 km3) and they were associated with caldera collapse as shown by the several hundred-metre-thick pyroclastic deposits and the long (>100 km) runout pyroclastic flow in case of the 13.1 Ma eruption. The 12.3 Ma Hegyköz and the 11.6 Ma Vizsoly eruptions were relatively smaller. The volcanic products can be readily distinguished by zircon and glass trace elements and trace element ratios, which can be used for fingerprinting and to correlate with distal deposits. The Rb, Ba, Sr content and strong negative Eu-anomaly of the glasses reflect extreme crystal fractionation, particularly for the Szerencs rhyolitic magma. The silicic volcanic products of the Tokaj Mts. show compositional similarities with the so-called ‘dry–reduced–hot’ rhyolite type consistent with an origin in an extensional environment, where the primary magmas were formed by near-adiabatic decompression melting in the mantle with subordinate fluid flux. In contrast, some of the older Bükkalja rhyolitic magmas evolved via more hydrous evolutionary paths, where amphibole played a role in the control of the trace element budget. The significant increase of zircon ε Hf values from −8.8 to + 0.2 in the rhyolitic pyroclastic rocks of Tokaj Mts. with time implies that mantle-derived magmas became more dominant. This can be explained by the specific tectonic setting, i.e. the final stage of subduction when the descending subducted slab became almost vertical, which exerted a pull in the upper lithosphere leading to thinning and accelerated subsidence as well as asthenospheric mantle flow just before the slab detachment.

Numerical simulation of pressure vessel explosions using metallic and composite materials: A comparative study

In light of the growing interest in hydrogen as an eco-friendly fuel source, ensuring the safe transportation of hydrogen is becoming increasingly vital for future mobility solutions. This research delves into the structural responses of various pressure vessel designs when exposed to explosive events, simulating hydrogen releases through finite element analysis. The study employs a TNT equivalent model to represent the energy liberated during a pressurized gas explosion. The objective is to compare the performance of metallic pressure vessels with two composite variants: one based on Quasi-Isotropic composites and the other utilizing the Double-Double fabrication technique. The analysis centers on stress and deformation within each model. The findings reveal that steel and Quasi-Isotropic models exhibited maximum stresses close to 5000 MPa, showcasing variations in stress distribution. In contrast, the Double-Double composite experienced higher stress levels, nearing 8000 MPa. In terms of deformation, steel exhibited the smallest displacement, followed by Quasi-Isotropic and Double-Double, with respective values of approximately 8 mm, 6 mm, and 4 mm.