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PADC is well known as a highly sensitive solid-state nuclear track detector. A proposal is for a radiation education method that utilizes these characteristics. A significant issue in the proposed educational method using PADC is the time-consuming etching process. This study attempted to reduce etching time by using a homemade PADC. The experimental results have revealed that the homemade PADC achieves faster etch pit enlargement compared to BARYOTRAK (commercial PADC). An attempt was made to enlarge etch pit diameters rapidly by irradiating UV at a wavelength of 253.7 nm and etching with NaOHaq/ethanol solution. The results revealed that UV irradiation at a wavelength of 253.7 nm, after etching, resulted in etch pit diameters several times larger than those obtained in conventional methods within the same etching time. Therefore, UV irradiation and short-time etching with NaOHaq/ethanol solution proved to be effective. This study also investigated the effects of fading on the PADC during its storage period after UV irradiation. The experimental results confirmed that the etch pit diameters shrank by approximately 30% after 2 months of storage. However, considering the enlargement effect of the etch pit diameters due to UV irradiation, it can be concluded that UV irradiation is practical for radiation education experiments.

During the armed conflict in Colombia, homemade improvised antipersonnel landmines were used to neutralize the adversary. Many active artifacts remain buried, causing damage to biodiversity by exploding. The extensive literature describes the effects and injuries caused to humans by conventional landmines. However, there is considerably less information on the behavior and effects of homemade antipersonnel landmines on fauna and good field investigation practices. Our objectives were to describe the characteristics of a controlled explosion of a homemade antipersonnel landmine (using ammonium nitrate as an explosive substance), to compare the effectiveness of some evidence search patterns used in forensic investigation, and to determine the effects on a piece of an animal carcass. The explosion generated a shock wave and an exothermic reaction, generating physical effects on the ground and surrounding structures near the point of explosion. The amputation of the foot in direct contact with the device during the explosion and multiple fractures were the main effects on the animal carcass. Finally, it was determined that finding evidence was more effective in a smaller search area. Many factors can influence the results, which must be weighed when interpreting the results, as discussed in this manuscript.

With the ever-increasing threat of improvised explosive devices (IEDs) and homemade explosives (HME) both domestically and abroad, detection of explosives and explosive related materials is an area of urgent importance for preventing terrorist activities around the globe. Canines are a common biological detector used in explosive detection due to their enhanced olfactory abilities, high mobility, efficient standoff sampling, and optimal identification of vapor sources. While other sensors based on different principles have emerged, an important concept for the rapid field detection of explosives is understanding key volatile organic compounds (VOCs) associated with these materials. Explosive detection technology needs to be on par with a large number of threats including an array of explosive materials as well as novel chemicals used in the manufacture of IEDs. Within this much needed area of research for law enforcement and homeland security applications, several studies have sought to understand the explosive odor profile from a range of materials. This review aims to provide a foundational overview of these studies to provide a summary of instrumental analysis to date on the various types of explosive odor profiles evaluated focusing on the experimental approaches and laboratory techniques utilized in the chemical characterization of explosive vapors and mixtures. By expanding upon these concepts, a greater understanding of the explosive vapor signature can be achieved, providing for enhanced chemical and biological sensing of explosive threats as well as expanding upon existing laboratory-based models for continued sensor development. [Display omitted] •Detection of explosives and their related materials is an area of urgent importance.•Understanding of volatile organic compounds (VOCs) is key to rapid field detection of explosives.•Enhanced olfactory abilities and high mobility makes canines an excellent tool in biological detection of explosives.•Explosive detection technology must stay up to date with current and expanding threats.•Experimental techniques provide understanding of explosive vapor odor signatures for enhanced sensor development.

Transmission of SARS-CoV-2 - the causative agent of COVID-19 - can be prevented through nonpharmaceutical interventions such as observing proper hand hygiene using alcohol-based hand rubs/sanitisers (ABHRs) as recommended by the WHO and local health authorities. However, this recommendation has led to high demand for ABHRs and proliferation of sub-standard products, which do not contain the recommended amount of alcohol. Fifty products of different origins and formulations obtained off-the-shelf and in public places in and around Pretoria (South Africa) were analysed for their alcohol content using gas chromatography. Ethanol was the most common alcohol used in the products, followed by isopropanol. Only 21 (42%) of the products analysed contained at least 70% alcohol; of these only 14 (28%) met the WHO recommended 80±5% alcohol content to have a virucidal effect on SARS-CoV-2. Of the 41 commercial off-the-shelf products analysed, 27 (66%) contained less than 70% alcohol in comparison to 13% of homemade products. Only 18% of gel products contained 70% alcohol, compared with 47% for liquid-based products. Most of the products did not contain the appropriate or correct declaration as recommended by the South African National Standards (SANS 289 and 490). The proliferation of substandard ABHRs is of great public health concern and calls for stricter regulations and enforcement in order to protect consumers, their rights and well-being during and post the COVID-19 pandemic period. However, in the interim, formulation of ABHRs using the WHO guidelines should be mandatory, as such formulations, when made correctly, do have the required virucidal effect against SARS-CoV-2.Significance: • Commercial, off-the-shelf and public hand sanitisers were analysed to determine whether they contained enough alcohol to be efficacious virucides as recommended by the WHO. • The majority of the products analysed were substandard, did not contain the recommended amount of alcohols and were not labelled correctly according to local and international standards. • Homemade products conformed to a greater degree to the WHO standards for alcohol-based hand sanitisers. It is evident from these results that there is a need to monitor the manufacture of off-theshelf products to ensure compliance and to assure consumers that products offer the required protection against SARS-CoV-2.

Synthesised N-substituted heterocyclic derivatives have ubiquitous applications in fine chemicals, pharmaceuticals, organic electronic materials, and agrochemicals. Numerous reports of photocatalytic C–N coupling in aid of a 5 W visible light source are documented in the literature which facilitates the cost reducibility, reusability, and promising methods for reaction. In this present work, we have designed and synthesised a benzimidazole-based sulphonic acid functionalized porphyrin photocatalyst (BSAFPPc) and confirmed by analytical techniques such as FT-NMR, FT-IR, and SEM/EDX. The BSAFPPc demonstrated an optical energy gap of 1.12 eV by using DRS. Further, the acidic potential was scrutinized by the Hammett acidity function which is H 0  = 0.99. The BSAFPPc was used for the C–N coupling of morpholine, and inactivated aryl halides comprising electron-donating (–NH 2, –OMe, –CH 3 ) and withdrawing groups (–CHO, –NO 2 ). This photocatalytic reaction produced an excellent practical yield from 60 to 90%. Further, the scope was extended to benzimidazole, pyrrole, indole and 1,2,4-triazole. The reaction has been experimented in an in-house homemade reactor system in a presence of a 5 W visible light source in an additive-free environment at ambient conditions. The photocatalyst was durable up to six photocatalytic cycles. The photocatalyst maintained its heterogenous nature which was asserted by the leaching test. Graphical Abstract

Understanding the properties of explosives is the basis for investigating and analyzing explosion cases. To date, due to the strict legal control of standard explosives and initiators, homemade pyrotechnics composed of oxidizers and fuels have become popular explosive sources of improvised explosive devices (IEDs) threatening greatly social stability and personal safety. The reactivity of pyrotechnics strongly depends on their intrinsic characteristics and operating conditions, which determine the efficiencies of heat and mass transfer between the reaction zone and the unreacted zone. Herein, the tests of thermodynamics, pressurization characteristics, and combustion propagation behaviors are conducted to explore the effects of oxidizer species, particle size, and loading density on the reactivity of homemade binary aluminum-based pyrotechnics. The results show that the pyrotechnics with potassium chlorate (KClO 3 ) have the strongest reactivity with the highest pressurization rate (d p /d t ) and the shortest combustion duration. Compared with their counterparts based on aluminum microparticles(mAl), pyrotechnics consisting of Al nanoparticles (nAl) possess superior reactivity as expected, which results from the relatively short heat and mass transfer distances. The nAl-based pyrotechnics have a low reaction exothermic peak temperature, great heat release, great aluminothermic reaction completeness, and high produced peak pressure with several orders of magnitude higher pressurization rate. Increasing the loading density of the pyrotechnics over a certain value can change the dominant mode of heat transfer from convective to conduction, sharply decreasing the pressurization characteristics and combustion front propagation velocities ( v p ). The results of theoretical calculations using the NASA-CEA codes show that loading density can alter the reaction process of the pyrotechnics, leading to a decrease in the predicted pressure per unit mass for Al/KNO 3 or Al/AP, and an increase for Al/KClO 3 . For nAl/potassium nitrate (KNO 3 ), the density is between 1.0 and 1.25 g cm −3 , across which d p /d t decreases by one order of magnitude from 0.148 to 0.014 MPa ms −1 . In addition, v p decreases by three orders of magnitude from 0.040 to 0.078 m s −1 . Distinct pressurization behaviors of nAl/AP are observed at a density of 1.5 g cm −3 , while the variation in nAl/KClO 3 reactivity fluctuates. These results are beneficial for the damage assessment of scenes caused by an explosion and for inversely calculating charge parameters.

As an important part of a factory’s automated production line, industrial robots can perform a variety of tasks by integrating external sensors. Among these tasks, grasping scattered workpieces on the industrial assembly line has always been a prominent and difficult point in robot manipulation research. By using RGB-D (color and depth) information, we propose an efficient and practical solution that fuses the approaches of semantic segmentation and point cloud registration to perform object recognition and pose estimation. Different from objects in an indoor environment, the characteristics of the workpiece are relatively simple; thus, we create and label an RGB image dataset from a variety of industrial scenarios and train the modified FCN (Fully Convolutional Network) on a homemade dataset to infer the semantic segmentation results of the input images. Then, we determine the point cloud of the workpieces by incorporating the depth information to estimate the real-time pose of the workpieces. To evaluate the accuracy of the solution, we propose a novel pose error evaluation method based on the robot vision system. This method does not rely on expensive measuring equipment and can also obtain accurate evaluation results. In an industrial scenario, our solution has a rotation error less than two degrees and a translation error < 10 mm.

Metal-containing compounds form a large and rapidly expanding group of high-energy materials. Many compounds in this class attract the attention of non-professionals, who may attempt the illegal production of explosives. Several of these substances have been commercially available and pose significant danger if used by terrorists or for criminal purposes. Others are experimental compounds, kinds of curiosities, often created by pyrotechnics enthusiasts, which can present serious risks to both the creators and their immediate surroundings. The internet hosts a vast amount of information, including recipes and discussions on forums, private websites, social media, and more. This paper aims to review the variety of metal-containing explosives and discuss their appeal and potential accessibility to unauthorized individuals.

Online social networks have become an everyday aspect of many people’s lives. Users spend more and more time on these platforms and, through their interactions on social media platforms, they create active and passive digital footprints. These data have a strong potential in many research areas; indeed, understanding people’s communication on social media is essential for understanding their attitudes, experiences, behaviors and values. Researchers have found that the use of social networking sites impacts eating behavior; thus, analyzing social network data is important for understanding the meaning behind expressions used in the context of healthy food. This study performed a communication analysis of data from the social network Twitter, which included 666,178 messages posted by 168,134 individual users. These data comprised all tweets that used the #healthyfood hashtag between 2019 and 2020 on Twitter. The results revealed that users most commonly associate healthy food with a healthy lifestyle, diet, and fitness. Foods associated with this hashtag were vegan, homemade, and organic. Given that people change their behavior according to other people’s behavior on social networks, these data could be used to identify current and future associations with current and future perceptions of healthy food characteristics.

Since the blueprints of the Liberator were published and successfully tested, countless new designs for said 3D-printed firearms and 3D-printed firearm components have been created and made publicly available. These new 3D-printed firearms, which are praised by their designers as ever more reliable, can be found on the Internet with little effort. Press reports have shown that various models of 3D-printed firearms have already been confiscated by law enforcement services around the world. So far, forensic studies have addressed this set of problems relatively little, whereby for the most part only the Liberator has been examined in detail and three other designs were only included a few times. The rapid pace of this development poses new challenges for forensic investigations and unveils new spheres of investigation regarding 3D-printed firearms. This research initiative aims to determine whether the results from previous studies on Liberators, are also reproducible and observable when using other models of 3D-printed firearms. In this respect six fully 3D-printed firearms – PM422 Songbird, PM522 Washbear, TREVOR, TESSA, Marvel Revolver and Grizzly – were produced on a material extrusion type Prusa i3 MK3S using PLA as the material. Test firings of these 3D-printed firearms have shown that they are indeed functional, but that, depending on the model, they suffer different levels of damage when fired. However, they were all rendered inoperative after one discharge and could not be used for further discharges unless the broken pieces were replaced. As in other studies, the firing process and the resulting ruptures on the 3D-printed firearm, projected polymer parts and fragments of different sizes and in different quantities into the immediate environment. The parts could be physically matched, allowing the reconstruction and identification of the 3D-printed firearms. Elements of ammunition also showed traces of melted polymer on the surface and cartridge cases bore tears or swellings. •Six fully 3D-printed (F3DP) firearms were produced on material extrusion printers.•These firearms were functional, but unreliable and inoperative after one discharge.•Typical traces of a 3D-printed firearm were generated after their discharge.•Damage suffered after a discharge affects the genesis of traces and their number.•Amount of polymer fragments found in the surroundings depended on the F3DP firearm.