Chemical Explosions Research Articles

Complex surface topographic changes from explosive experiments at the Dry Alluvium Geology site, southern Nevada, United States

Understanding the surface topographic change that results from underground explosions is important for global security. Current techniques to relate the surface change to underground explosion characteristics usually involve assuming the earth has homogenous properties, leading to highly variable interpretations. Here we use an unoccupied aerial platform and a digital single lens reflex camera along with 200+ ground control points surveyed with a real-time kinematic global navigation satellite system to measure the surface topographic change resulting from two underground explosions at the Dry Alluvium Geology site in Yucca Flat, Nevada National Security Site, southern Nevada, United States. We find areas of 5–7 cm of subsidence that are not directly above the explosion source but rather 200–300 m away. For experiment DAG2, this zone is located south and west of the explosion, while for DAG4, there is a zone of subsidence located northeast of the explosion. In addition, late-time measurements show as much as 5 cm of horizontal change without measurable associated vertical change in the weeks following DAG4 but not DAG2. These indicate that the deformation resulting from underground chemical explosions can be very complex and bear little to no resemblance to predictions using half-space models. It is likely the tectonic environment plays a significant role in controlling the surface change, but the details are not fully understood.

Evaluation of the EarthSHAB Stratospheric Solar Hot Air Balloon Flight Prediction Model Using Balloon Trajectory Data

Abstract The heliotrope is a solar balloon design which is constructed out of painter’s plastic, and the exterior is coated in charcoal powder. Darkening the plastic gives the balloon a high solar absorptance, which allows it to ascend into the lower stratosphere and float for hours at a time. The balloons have previously been used to lift scientific instruments into the stratosphere to study chemical explosions, earthquakes, and stratospheric aerosols. They have also been proposed as a platform for planetary exploration. Flight predictions are crucial to preflight planning to reduce safety risks and meet flight objectives. However, there exists a wide range of possible flight paths due to varying environmental conditions and solar balloon configurations. EarthSHAB is one such software that was designed to support flight planning using the weather forecasts and balloon properties to predict the flight path of a solar balloon. We compare EarthSHAB-simulated flight paths to a set of observed flight paths for the 3.5-m diameter heliotrope design called the “Cloudskimmer.” Using the criteria that the modeled paths must fall within 5% of the observations to be considered successful, we found that EarthSHAB successfully predicted the Cloudskimmer ascent rate and average float altitude 10% and 90% of the time, respectively. We also found that the average difference in the observed and predicted landing locations was 97 km and landing times were 54 ± 38 min. Significant deviations between the observed and predicted ascent rates and excursions at float were found to be associated with heavy payloads and convective cloud development, respectively. Significance Statement Solar balloons are used to lift scientific instruments into the lower stratosphere for hours at a time to study chemical explosions, earthquakes, stratospheric aerosols, and more. The flight paths of solar balloons can be difficult to predict due to variability in their design and surrounding environment. We evaluate the accuracy of EarthSHAB, a software that predicts the altitude profile and horizontal trajectory of a solar balloon using inputs such as the weather, balloon size, and balloon mass. Our results suggest that for the balloon design used in this study, EarthSHAB is best suited for modeling the behavior of balloons with lightweight payloads that do not fly within or directly above clouds.

Micro-Electrochemical Sensor Array for Detection of Serotonin

Chemical and biological threats pose a significant risk to national security, whether arising from natural outbreaks, accidental releases, warfare, or terrorism. Consequently, there's an urgent demand for innovative technologies capable of real-time screening, detection, and forensic analysis, especially concerning chemical warfare agents, explosives, and nuclear monitoring in field operations. Advancements in biosensing have revolutionized the detection of contaminants using diverse techniques. One notable breakthrough involves synthetic biology, which has led to the creation of biosensor devices capable of monitoring chemical and physical contaminants. These devices can conveniently display detected contaminants as visual signals, such as fluorescence and bioluminescence. However, due to lack of the advances in bio-electronics interfaces, these sensors are not ubiquitous for chemical and biological sensing electronic systems.In this context, we present the development of a Bio engineered microfabricated electrochemical sensor to detect serotonin by producing hydrogen peroxide (H2O2). The study entails COMSOL simulations aimed at understanding the electrochemical behavior of the electrode for detection of H2O2 by identifying relevant physics, determining the necessary parameters for the simulation concerning the solution and materials, and conducting experiments to validate the electrochemical signal, particularly the charge transfer density. Three distinct electrode geometries are explored in this experiment: the unpatterned electrode, the interdigitated electrode, and the ring array electrode. The performance of the ring electrode is experimentally evaluated for its ability to detect H2O2 levels ranging from 0 to 250 parts per million (ppm).

Explosion resistance of self-balancing hyperboloid multilayered sandwich panels with hybrid cores

This study introduces an innovative protective structure featuring a hyperbolic multilayered sandwich design with hybrid cores. The structure integrates orthogrid and fold-cores, which can be supplemented with polyethylene foams to enhance energy absorption. Experimental evaluations, including chemical explosions and simulated nuclear blasts, were conducted on these self-balancing hyperboloid folded-core sandwich panels (SHFSPs). The results indicate that the SHFSPs successfully resisted the impact of 0.7386 m/kg1/3 and a simulated nuclear explosion with a peak pressure of 0.75 MPa, showing no signs of damage. Additionally, after filled with foam, the SHFSPs endured a chemical explosion of 0.5894 m/kg1/3 and a simulated nuclear blast with a peak pressure of 0.80 MPa, remaining undamaged. This study underscores the SHFSPs' potential as a robust blast-resistant solution, suitable for a variety of engineering applications.

Analysis of the Causes and Configuration Paths of Explosion Accidents in Chemical Companies Based on the REASON Model

Explosion accidents, representing one of the most severe accident types within the chemical industry, pose substantial threats to personnel safety, economic losses, and environmental pollution, among other consequences. This paper constructs a research framework based on the REASON theory, utilizing accident investigation reports of 30 typical chemical enterprise explosion accidents in China from 2013–2022 as research samples. The fsQCA method is employed to deeply explore the influencing factors and causal configuration pathways of chemical explosion accidents from a configurational perspective. The study findings indicate that the occurrence of explosions in chemical enterprises is the result of the coupled effects of multiple factors, with five complex accident causation configurations, which can be summarized into the following three categories: organizational management deficiencies, supervision deficiencies, and behavior–risk linkages. Organizational management and safety supervision have a direct and significant impact on the occurrence of explosions in chemical enterprises and are key factors in the accidents. The research conclusions contribute to a rational understanding of the complex causes of explosions in chemical enterprises and provide practical guidance for the prevention and control of such accidents.

Theoretical Perspective on the Sensing Mechanism of a Pyrazinium‐Based Fluorescent Probe Towards 2,4,6‐Trinitrophenol

ABSTRACTRapid detection of chemical explosives plays a critical role in national security and public safety. An in‐depth study of the sensing mechanism is particularly urgent for the development of highly efficient, sensitive, and selective chemical sensors for the precise detection of chemical explosives. Density functional theory (DFT) and time‐dependent DFT approaches were used in this work to examine the sensing mechanism of a novel fluorescent probe 1‐benzyl‐3,5‐di (thiophen‐2‐yl)pyrazin‐1‐ium bromide (BTPyz) for the detection of 2,4,6‐trinitrophenol (TNP). A comprehensive theoretical exploration was carried out, and a different interaction mode between the probe and TNP from that in the original experiment was proposed. The π–π stacking was established to be the recognition interaction between BTPyz and TNP anion, and the active site was determined from the three potential sizes according to the Gibbs free energy analysis results. The rationality of the reaction mode and the π–π stacking product between the BTPyz and TNP (BTN) was further confirmed by the fluorescence properties (absorption and emission spectra). According to the findings of frontier molecular orbitals (FMOs), photoinduced electron transfer (PET) is the intrinsic mechanism through which TNP quenches the probe's fluorescence.

Visualization of integrated failure consequences of hazardous chemical leakage and explosion

Dangerous chemicals are widely present in various aspects of people's lives, but they often pose risks of leakage and explosion during transportation and storage, resulting in severe casualties and property damage. Firstly, this paper proposes a visualization method applicable to comprehensive failure consequences of hazardous chemical storage tanks. This method considers the toxic hazard range of chemical leaks and the blast overpressure injury range of leak clouds and visualizes the comprehensive failure consequences. Secondly, FLACS is employed to simulate a major leakage and explosion accident at Jinyu Petrochemical Co., Ltd. in Linyi City. The simulation reproduces the leakage and explosion processes and verifies the reliability of the simulation results. Finally, the proposed method is used to visualize the comprehensive failure consequences of this accident, providing comprehensive visual results. The method presented in this paper can serve as a theoretical reference for predicting the development of accidents and clarifying their consequences.

Beirut 2020 explosion and health system response: An alarm for the dangerous consequences of Natech incidents in industrial cities.

The blast on August 4, 2020, which destroyed main parts of the Port of Beirut, was one of the largest chemical explosions in history. This incident is considered one of the events of the Natural Hazards Triggering Technological Accidents (Natech) group, which is accompanied by explosion, fire, and leakage of gaseous toxic materials.

Combustion-explosion suppression and environmental protection of typical sulfur-containing hazardous chemicals.

Sulfur, as a crucial chemical raw, poses increased combustion-explosion risks when mixed with other hazardous substances due to its dual nature as both an oxidant and a reducing agent. Additionally, sulfur-induced combustion and explosions can result in environmental pollution. Combustion-explosion suppression technology plays a crucial role in industrial production by effectively preventing hazardous chemical explosion incidents. This research investigates the combustion-explosion suppression of black powder, a common hazardous chemical containing sulfur, by utilizing two solid-based blast suppressants, NH4H2PO4 and NaHCO3. On this basis, examining changes in the oxidation states of sulfur and explaining the mechanisms of combustion-explosion suppression through the examination of combustion-explosion products. Additionally, numerical calculations are employed to analyze the evolution patterns of gaseous and solid-phase products throughout the entire combustion-explosion process. Research indicates that NaHCO3 exhibits a more effective combustion-explosion suppression effect on black powder compared to NH4H2PO4, which attributed to the valence state transformation of sulfur and the reduction of carbon oxidation. Furthermore, with the enhancement of combustion-explosion suppression effect, K2S, which a pollutes the environment, is gradually transform converted into potassium fertilizer K2SO4, which benefits plants. These results offer new insights into the research of combustion-explosion suppression of sulfur-containing substances and environmental protection strategies.

Efficient integrated production of bioethanol and lignin from oil palm empty fruit bunch biomass using chemical steam explosion method

Efficient integrated production of bioethanol and lignin from oil palm empty fruit bunch biomass using chemical steam explosion method

Modeling the fire scenario in the diesel storage tank of the Iran’s specialized hospital using PHAST software

Background and Objective: Diesel storage tanks play a crucial role in hospitals and are constantly at risk of chemical release, explosion, and fire. The purpose of this study was to examine the consequences of a diesel tank leak in one of the Iran’s specialized hospitals. Materials and methods: This study utilized an applied research approach with scenario modeling using PHAST software version 8.4. A discharge rate of 1000 L/min was employed for the fixed-duration release scenario. The necessary information for the software, including tank and meteorological data, was collected. The mortality rate and danger radius were calculated and analyzed for two tank volumes of 23600 and 12000 m3 in conditions of Sabzevar region in winter and 1.5 F of the software. Results: According to the tank type and substance release into the environment, the software showed a pool fire. The most hazardous scenario was determined to be leakage from the 23600 m3 tank in Sabzevar's weather conditions (26 0C, wind speed 15 m/s in winter). The maximum and minimum radiation heat from the fire were calculated at 44.7 and 94.2 meters, respectively. The mortality rates for exposure levels of 37.5 kw/m2, 12.5 kw/m2, and 4 kw/m2 were found to be 98.7%, 6.5%, and approximately zero, respectively. Conclusion: Fire safety in hospitals is a critical issue that requires a thorough examination of the factors that can lead to ignition and explosion.

The Korean infrasound catalogue (1999–2022)

SUMMARY The Korean infrasound catalogue (KIC) covers 1999–2022 and characterizes a rich variety of source types as well as document the effects of the time-varying atmosphere on event detection and location across the Korean Peninsula. The KIC is produced using data from six South Korean infrasound arrays that are cooperatively operated by Southern Methodist University and Korea Institute of Geoscience and Mineral Resources. Signal detection relies on an Adaptive F-Detector that estimates arrival time and backazimuth, which draws a distinction between detection and parameter estimation. Detections and associated parameters are input into a Bayesian Infrasonic Source Location procedure. The resulting KIC contains 38 455 infrasound events and documents repeated events from several locations. The catalogue includes many anthropogenic sources such as an industrial chemical explosion, explosions at limestone open-pit mines and quarries, North Korean underground nuclear explosions and other atmospheric or underwater events of unknown origin. Most events in the KIC occur during working hours and days, suggesting a dominance of human-related signals. The expansion of infrasound arrays over the years in South Korea and the inclusion of data from the International Monitoring System infrasound stations in Russia and Japan increase the number of infrasound events and improve location accuracy because of the increase in azimuthal station coverage. A review of selected events and associated signals at multiple arrays provides a location quality assessment. We quantify infrasound events that have accompanying seismic arrivals (seismoacoustic events) to support the source type assessment. Ray tracing using the Ground-to-Space (G2S) atmospheric model generally predicts observed arrivals when strong stratospheric winds exist, although the predicted arrival times have significant discrepancies. In some cases, local atmospheric data better captures small-scale variations in the wind velocity of the shallow atmosphere and can improve arrival time predictions that are not well matched by the G2S model. The analysis of selected events also illustrates the importance of topographic effects on tropospheric infrasound propagation at local distances. The KIC is the first infrasound catalogue compiled in this region, and it can serve as a valuable data set in developing more robust infrasound source localization and characterization methods.

Investigation of hydrogen/air co-flow jet flame propagation mechanism in supersonic crossflow

The design of fuel injection schemes is crucial for improving the combustion performance of high-Mach number scramjet. To clarify the feasibility of the coaxial jet injection scheme, high fidelity Large Eddy Simulation of the supersonic coaxial jet flame is conducted. The simulations are in good agreement with the experimental results in terms of time-averaged velocity, temperature, and species distribution. Auto-ignition phenomenon and the characteristics of partially premixed flame are well captured. The introduction of co-flow air increases the vorticity magnitude close to the injection port and downstream near-wall region, which results in a 400 K rise in the time-averaged temperature on the downstream near-wall region and a 4% increase in the proportion of premixed combustion near the injection port. Moreover, the instantaneous distribution of hydroxy radical indicates that the spanwise width of the windward reaction shear layer is reduced utilizing the coaxial jet scheme. Chemical kinetic analysis is applied to reveal the propagation mechanism of partially premixed flames. Thermal explosion is the chemical explosion mode for all coaxial jet flame front, which are dominated by a high-temperature reaction path. The low-temperature reaction path mainly exists in the transverse jet injection port, downstream near-wall region of the single transverse jet and co-flow lifted flame base. These significant findings provide valuable insights for the potential engineering application of the coaxial jet injection scheme to a high Mach number scramjet.

Shallow Soil Response to a Buried Chemical Explosion With Geophones and Distributed Acoustic Sensing

Shallow Soil Response to a Buried Chemical Explosion With Geophones and Distributed Acoustic Sensing

A macro-scale constitutive model of low-density cellular concrete for blast simulation

Cellular concrete is a building material with highly porous structure in the matrix. Due to its excellent thermal and sound insulation performance, low-density cellular concrete (≤600 kg/m3) is often used in the construction of non-structural elements in residential and industrial buildings. During service, low-density cellular concrete elements may be subjected to blast loads induced by chemical or gas explosions. Therefore, a material model that can accurately describe the mechanical behavior of low-density cellular concrete is essential to investigate the damage and dynamic response of cellular concrete elements subjected to blast loading. Previous study indicated that low-density cellular concrete exhibits a cap-shaped compressive meridian. However, the commonly used brittle material models adopt the basis of a monotonical increase in the deviatoric strength with increasing hydrostatic pressure, which is contradictory to the experimental observations of low-density cellular concrete. Therefore, this study aims at developing a material model for predicting the dynamic response of low-density cellular concrete elements subjected to blast loads. Firstly, a series of laboratory tests were conducted to study the mechanical properties of low-density cellular concrete. The quasi-static, triaxial and dynamic properties, including the damage evolution modes, the compressive meridian, the hydrostatic pressure-volumetric strain relationship, and the strain rate effects were identified. Secondly, a plastic-damage material model of low-density cellular concrete was proposed and the material parameters were calibrated by the laboratory test results. To verify the feasibility of the model, single element simulations were carried out and results indicated that the model can accurately describe the complex behavior of low-density cellular concrete. Thirdly, numerical simulations were conducted to validate the proposed model by comparing predictions with blast test results from the literature. The numerical model accurately predicted the displacement responses and failure processes of low-density cellular concrete elements, with a maximum difference of 21 mm for maximum displacement and only 2 mm for residual displacement. The results demonstrate the high accuracy of the developed model in predicting the dynamic response and damage of low-density cellular concrete elements under various blast loading scenarios.

Development of In-Needle SPME Devices for Microextraction Applied to the Quantification of Pesticides in Agricultural Water.

The chemical industry explosion in the 20th century has led to increased environmental pollution, affecting fauna, flora, and waterways. These substances alter water's taste, color, and smell, making it unfit for consumption or toxic. Agricultural water networks face threats from pollution before and after treatment. Some chemical contaminants, like pesticides, are embedded in natural biogeochemical cycles. In this study, we developed a simple and low-cost procedure for the fabrication of needles coated with polydimethylsiloxane (PDMS) as an efficient sorbent for the microextraction of organic pollutant traces from water. The prepared needles were used as an alternative for commercial solid-phase micro-extraction (SPME) devices in analytical chemistry. The PDMS polymeric phase was characterized by Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry (TGA), and scanning electron microscopy (SEM). The PDMS-coated needles were used for extraction of thirteen pesticides by direct-immersion solid-phase microextraction (DI-SPME) from contaminated waters, followed by determination with gas chromatography-mass spectrometry (GC-MS). The developed analytical method showed limits of detection (LODs) between 0.3 and 2.5 ng mL-1 and RSDs in the range of 0.8-12.2%. The homemade needles were applied for the extraction of pesticides in surface and ground aqueous samples collected from an agricultural area. Several target pesticides were identified and quantified in the investigated water samples.

The FIRE-IN project: Tsunami-risk related practitioner challenges and 3rd cycle overall results

This article summarizes the methodology for the identification of practitioners’ challenges, in the context of the H2020 funded project FIRE-IN (Fire and Rescue Innovation Network) activities. The project consisted of five thematic areas or “Thematic Working Groups”, as they are called, i.e., Search and Rescue Emergency Response, Structure Fires, Landscape Fires Crisis Mitigation, Natural Hazard Mitigation and Chemical Biological Radiological Nuclear and Explosives, and three iterations, each one including the identification of capability challenges, the screening for solutions, that can potentially address these challenges, and the request for ideas regarding future innovations that will complement already existing ones and will assist in covering capability gaps. This article focuses on the natural hazard mitigation working group and tsunamis in the Mediterranean region as a case study for the 3rd and last iteration of the project. The scenario of a tsunami occurrence in the Mediterranean is the basis for the FIRE-IN 3rd cycle workshop, as an indicative example of a high impact – low probability event, which aims to identify practitioners’ Future Common Capability Challenges in Europe. The current status of the tsunami hazard in Europe, national and international tsunami risk mitigation measures and procedures and operational experience from recent events are also discussed. Focus is provided on the natural hazard mitigation and tsunami related practitioners’ challenges, while results from the FIRE-IN request for ideas process and the interaction between practitioners, researchers and industry are also discussed. The aim is to present practitioners’ current and future capability challenges , one of the main outcomes of the FIRE-IN project, and to provide further guidelines to stakeholders of disaster management towards a safer Europe, mainly, through preparedness and adaptation for stronger and resilient societies.

Airblast observations and near-field modeling of the large surface explosion coupling experiment

Seismoacoustic wave generation for two consecutive surface chemical explosions of the same yield (approximately 1 ton TNT-equivalent) was studied during the Large Surface Explosion Coupling Experiment (LSECE) conducted at Yucca Flat on the Nevada National Security Site (NNSS) site in alluvium geology. We have performed numerical simulations for both chemical explosions to investigate how the non-central source initiation, site topography and soil mechanical properties affect the evolution of the explosion (fireball and cloud), its crater, and variations in the generated blast waves. The results can be used to improve the understanding of surface explosions and their effects and how those effects can be used to infer source information such as explosive yield and emplacement. We find that the non-central detonation of the explosive cube results in non-axisymmetric blast overpressures which persist through the strong and weak shock regimes, in this case out to 200 m and more. The pattern of the secondary shock (i.e., shock created due to slowing explosive products within the expanding fireball) is also affected and its arrival relative to the main shock and may be indicative of explosive type due to its dependence on the explosive products ratio of heats. Small reflections are visible within the overpressure signal that are most probably due to small artifacts in blast path. Importantly, the fireball growth, cavity generation, and cloud formation also depart from spherical and ideal approximations due to ground interactions and material dependence, which shows the importance of realistic geomaterial models for accurate prediction. The asymmetry in peak overpressure is diminished for the second chemical explosion, which was placed in the crater of the first. Numerical modeling shows that the explosive jetting created by the non-central detonation is reduced upon interaction with the crater walls and this has the effect of making the blast generation more axisymmetric.

Seismic Characterization of Subsurface Structures at Rock Valley, Nevada

ABSTRACT The Source Physics Experiment (SPE) aims at improving explosion monitoring techniques by investigating source characteristics of chemical explosions in geologic formations. One of the critical tasks in Rock Valley Direct Comparison (RV/DC), SPE phase III, is to prepare for the main experiment by characterizing the subsurface structures at the test site. Based on the seismic data acquired during an accelerated-weight-drop (AWD) seismic survey at Rock Valley, we first pick the P-wave first-arrival travel times and derive a P-wave velocity model using the adjoint-state first-arrival travel-time tomography. We then apply reverse-time migration to the processed seismic data and obtain high-resolution images of the subsurface structures along the two main survey lines. Our migration results show several reflectors corresponding to major geologic formation boundaries. We employ a multitask machine learning model to enhance the reverse-time migration images and identify faults from these images. We find that our automatically picked faults correlate well with the locations of known faults in the region in addition to many geologically undetected faults. Our subsurface characterization results refine our understanding of the geology in this region and provide valuable velocity and structural information for RV/DC geologic model building and fault identification.

Spatially Dependent Seismic Wavefield Scattering from an Underground Chemical Explosion: Analysis of the Source Physics Experiment Dry Alluvium Geology Large-N Array

ABSTRACT Explosion sources have been observed to generate significant shear-wave energy despite their isotropic nature. To investigate this phenomenon, we conduct an analysis of the seismic data collected as part of the Source Physics Experiment (SPE): Dry Alluvium Geology (DAG) and investigate the generation of shear-wave energy via scattering. The data were produced by three underground chemical explosions and consist of three-component seismograms, which were recorded by the DAG Large-N array. Synthetic tests suggest that for the DAG experiments, small-scale stochastic heterogeneities, defined as features with correlation lengths of 10–100s of meters, are more effective than large-scale geologic structure (scales >1–10 km) at reproducing the scattering of explosion generated wavefields observed at DAG. We analyze the seismic data for spatially variable ratios between transversely and radially polarized seismic energy, and then estimate the mean free path of P and S waves. All analyses are conducted within a frequency band of 5–50 Hz. The ratio of transversely to radially polarized energy is the highest in the east and west portion of the Large-N array. In addition, the magnitude of the estimated S-wave mean free path is shorter in the eastern portion of the Large-N array. This variation indicates that the eastern area of the DAG array is where more scattering is occurring, suggesting azimuthal dependence of P-to-P and P-to-S scattering. This azimuthal dependence of P-to-S scattering can have implications for explosion discrimination based on spectral ratios of seismic wave types, because the general assumption is that explosions do not generate shear-wave energy. Synthetic tests modeling only larger-scale geologic structure had lower transversely polarized energy (only four stations showing a transversely to radially polarized energy ratio greater than 1) and fewer stations (<10) displaying shorter (<300 m) mean free paths than what was observed in the DAG data results.