Accidental Explosions, Beirut ANFO Blast, Ghana Truck Explosion, Global Terrorism Index 2021-22, and Blast Mitigation: A Review

Explosions are continually occurring without ceasing in many parts of the world endangering human lives and seriously affecting the health of infrastructures and facilities. Industry accidental mishaps that occurred recently, like those in Ghana (2022; 17 deaths), Russia (2021; 18 deaths), Beirut (2020; 220 deaths; $8bn economic loss), and Tientsin (2015, 173 deaths;$6.86bn economic loss), indicate the severity of the industrial devastation one could gauge that explosions may cause. Very recently, another industrial blast occurred at a rocket and explosive factory in the capital city of Turkey leading to the collapse of a nearby building and causing 5 deaths and serious injuries to over 50 civilians, is an eye-opener. This article offers a condensed examination of subjects related to explosions, including accidental detonations, the Beirut ANFO explosion, and the Ghana truck explosion. The report findings from the global terrorism index 2021-22 are analyzed and discussed. Additionally, strategies for both active and passive measures to mitigate the impact of explosions on infrastructure and facilities are emphasized. To ensure safety and durability against damage, the structure needs to possess resilience in the face of explosions. Therefore, it is crucial to analyze how the structure responds to extreme loading in order to enhance the design philosophy. Currently, there is still a lack of understanding regarding the mechanism of blast and how it affects masonry structures. Consequently, further research is required to delve deeper into this subject

Effect of Impactor's Taper Angle on the Response of a Square Slab to a Falling Mass

Reinforced concrete (RC) slabs during their service life experience falling mass impacts which are significantly different from quasi-static loading on account of short-term load transference and higher strain rate. Slab being a thin flexural member is prone to short-term dynamic loadings susceptible to irreparable damage or even collapse. Considerable research has been done with round impacting mass, however, the impacting mass needs not necessarily be round and may have a different geometry such as a rolling boulder or fragmented rock mass. To simulate the practical impacting geometries of the falling mass, eight different variations of the geometries varying from flat of 300mm diameter followed by 40mm flat with tapering from 90° to 0° in increments of 15° keeping the material characteristics and drop height of the falling mass constant across all the eight cases, have been considered herein to investigate the influence of impactor’s taper angle on the anti-impact response of the validated square slab in Abaqus Explicit package program. A comparison of several response parameters including displacement, damage, stress distribution, and plastic dissipation energy has been done with the validated model, and the geometries of the impactor causing the maximum and minimum damages are identified. A key finding from this study is that all considered impacting geometries lead to bond failure in the lower layer of the re-bars, however, the impactors having the geometry with taper angles below 45° possess the capacity to induce bond failure in the re-bars of the upper layer too, beyond the impacted region

Widely Employed Constitutive Material Models in Abaqus FEA Software Suite for Simulations of Structures and Their Materials: A Brief Review

The structural response of masonry/concrete structures depends upon the load-carrying mechanism and subsequently deformations produced by loads carried. In masonry/concrete structures, identification of the stress/strain imposing stress conditions and strain hardening/softening makes the structural response more complicated. Elastic damage models or elastic-plastic constitutive laws are inadequate to simulate masonry/concrete response under high strain-rate loadings. Further, irreversible or plastic strain cannot be realized using the elastic damage model. Several constitutive damage models are available in the literature. In this article, a concise explanation of the functioning of different material models in the Abaqus software package has been provided. These models include concrete damage plasticity for concrete and masonry, traction separation constitutive laws for brick-mortar interface, Hashin's criteria for CFRP, Johnson-Cook plasticity for steel, and crushable foam plasticity hardening for metallic foams. Researchers frequently utilize these models for numerical simulations and modeling of infrastructural elements and their respective materials when subjected to various structural loads. Besides, this paper presents a discourse on problem-solving methods and a comparison between explicit and implicit analysis. The research provides valuable input to researchers and practitioners in the field of structural engineering for an in-depth understanding of the functioning of Abaqus' pre-existing material models

In vitro evaluation of electroporated gold nanoparticles and extremely-low frequency electromagnetic field anticancer activity against Hep-2 laryngeal cancer cells

Introduction. The extremely-low frequency electromagnetic field (ELFEMF) has been proposed for use in cancer therapy since it was found that magnetic waves interfere with many biological processes. Gold nanoparticles (Au-NPs) have been widely used for drug delivery during cancer in vitro studies due to their low cytotoxity and high biocompatibility. The electroporation of cancer cells in a presence of Au-NPs (EP Au-NPs) can induce cell apoptosis, alterations of cell cycle profile and morphological changes. The impact of ELFEMF and EP Au-NPs on morphology, cell cycle and activation of apoptosis-associated genes on Hep-2 laryngeal cancer cell line has not been studied yet. Materials and methods. ELFEMF on Hep-2 cells were carried out using four different conditions: 25/50 mT at 15/30 min, while Au-NPs were used as direct contact (DC) or with electroporation (EP, 10 pulses at 200V, equal time intervals of 4 sec). MTT assay was used to check the toxicity of DC Au-NPs. Expression of CASP3, P53, BAX and BCL2 genes was quantified using qPCR. Cell cycle was analyzed by flow cytometry. Hematoxylin and eosin (HE) staining was used to observe cell morphology. Results. Calculated IC50 of DC Au-NPs 24.36 μM (4.79 μg/ml) and such concentration was used for further DC and EP AuNPs experiments. The up-regulation of pro-apoptotic genes (CASP3, P53, BAX) and decreased expression of BCL2, respectively, was observed for all analyzed conditions with the highest differences for EP AuNPs and ELFEMF 50 mT/30 min in comparison to control cells. The highest content of cells arrested in G2/M phase was observed in ELFEMF-treated cells for 30 min both at 25 or 50 mT, while the cells treated with EP AuNPs or ELFEMF 50 mT/15 min showed highest ratios of apoptotic cells. HE staining of electroporated cells and cells exposed to ELFEMF’s low and higher frequencies for different times showed nuclear pleomorphic cells. Numerous apoptotic bodies were observed in the irregular cell membrane of neoplastic and necrotic cells with mixed euchromatin and heterochromatin. Conclusions. Our observations indicate that treatment of Hep-2 laryngeal cancer cells with ELFEMF for 30 min at 25–50 mT and EP Au-NPs can cause cell damage inducing apoptosis and cell cycle arrest

ICZM and WTP of stakeholders for beach conservation: Policymaking suggestions from an Italian case study

In accordance with integrated coastal zone management (ICZM), private stakeholders could be asked to pay for the benefits from beach conservation projects. Since a private contribution is measured by the amount of other goods a person is willing to give up for beach quality, it can be solicited in monetary terms or, when possible, in other forms, such as specific works. In this paper, by analysing the results of two surveys in Italy concerning stakeholders' perceptions of ICZM and their willingness to pay for these benefits, suggestions for beach management are provided to policymakers. One survey focuses on beach visitors who are asked to pay in monetary terms, while the other focuses on sunbathing establishment managers, who are asked to pay not only in monetary terms but also through beach works. The results show that the majority of these stakeholders are fully or partially aware of what ICZM is, and are unwilling to pay. However, regression analysis of those willing to pay suggests that promoting an information and education campaign about ICZM may be important if stakeholders' probability of paying is to be increased

Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

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