Characteristics of Ultrasensitive Hexagonal-Cored Photonic Crystal Fiber for Hazardous Chemical Sensing

A highly sensitive non-complex cored photonic crystal fiber sensor for hazardous chemical sensing with water, ethanol, and benzene analytes has been proposed and is numerically analyzed using a full-vector finite element method. The proposed fiber consists of a hexagonal core hole and two cladding air hole rings, operating in the lower operating wavelength of 0.8 to 2.6 µm. It has been shown that the structure has high relative sensitivity of 94.47% for water, 96.32% for ethanol and 99.63% for benzene, and low confinement losses of 7.31 × 10−9 dB/m for water, 3.70 × 10−10 dB/m ethanol and 1.76 × 10−13 dB/m benzene. It also displays a high power fraction and almost flattened chromatic dispersion. The results demonstrate the applicability of the proposed fiber design for chemical sensing applications.

On the problem of cognition of mineralogy and geochemistry of the landscape of mining territories

A methodology for studying the forms of finding chemical elements in the landscape of mining territories is given. The necessity of mineralogical and geochemical integration of methods is shown, the influence of the forms of occurrence of chemical elements in the landscape on the extent of their absorption by biota, in particular, the coefficient of biological absorption. The dependence of the forecast of the state of mining geosystems on the forms of presence of potentially hazardous chemical elements in them is determined.

A Complementary Silicon Quantum Dot-Enzyme Platform for Selective Detection of Nitroaromatics Compounds

To address the issue of poor selectivity in nanotechnology-driven, portable nitroaromatics sensors, we have coupled a ratiometric photoluminescence sensor based on silicon quantum dots and fluorescent proteins with a colorimetric enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds – specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4-dinitrotoluene and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors which can accurately identify hazardous chemical species.

A Complementary Silicon Quantum Dot-Enzyme Platform for Selective Detection of Nitroaromatics Compounds

To address the issue of poor selectivity in nanotechnology-driven, portable nitroaromatics sensors, we have coupled a ratiometric fluorescence sensor based on silicon quantum dots and fluorescent proteins with a colorimetric, enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds – specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4- dinitrotoluene and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors which can accurately identify hazardous chemical species.

Biological Synthesis of Metallic Nanoparticles from Different Plant Species

Green chemistry for the synthesis of different nanoparticles (NPs) from metal has become a new and promising field of research in nanotechnology in recent years. The inspire applications of metal oxide NPs have attracted the interest of researchers around the world. Various physical, chemical and biological methods in material science are being adapted to synthesize different types of NPs. Green synthesis has gained widespread attention as a sustainable, reliable, and eco-friendly protocol for biologically synthesizing a wide range of metallic NPs. Green synthesis has been proposed to reduce the use of hazardous compounds and as a state of a harsh reaction in the production of metallic NPs. Plants extract used for biosynthesis of NPs such as silver (Ag), cerium dioxide (C2O2), copper oxide (CuO), Gold (Au), titanium dioxide (TiO2), and zinc oxide (ZnO). This review article gives an overview of the plant-mediated biosynthesis of NPs that are eco-friendly and have less hazardous chemical effects.

Comparative Study of the Hazardous Chemical Transportation Accident Analyses Using the CREAM Model and the 24Model

Compared with other types of transportation, hazardous chemical transportation is more dangerous and more likely to cause accidents, such as combustion and explosion. To better study the advantages of different accident analysis models and realize the sustainable development of the accident analysis, this paper compares the 24Model and the cognitive reliability and error analysis method in their analyses of causes of hazardous chemical transportation accidents. Regarding their analyses of the causes of hazardous chemical transportation accidents, the causal factors of hazardous chemical transportation accidents are obtained. Then the analysis results of the two models are compared on three aspects: the object of accident influence, the module of accident analysis, and the number of accident causes. Gray correlation analysis and regression analysis are used to quantitatively compare and verify the focus of the two models on the cause of the accident. The results show that the 24Model emphasizes the safety culture of the enterprise, the cognitive reliability and error analysis method emphasizes the technology of the enterprise, and the two accident analysis models provide different emphases on preventing accidents to better achieve the goal of sustainable development.

Changes in Risk in Medium Business Plating and Paint Manufacturing Plants following the Revision of the Korean Chemical Accident Prevention System

Chemical accidents can occur anywhere. The need for chemical management in Korea was realized following the 2012 Gumi hydrofluoric acid accident in 2012. The Chemicals Control Act was enacted in 2015. This system evaluates the risks (high, medium, low) and consequent safety management at all plants that handle hazardous chemical substances. However, the system was criticized as excessive when most plants were designated high-risk without considering their size. Thus, laboratories and hospitals handling very small quantities were subject to regulation. Accordingly, in 2021 Korea revised the system to include off-site consequence analyses and a Korean-style risk analysis. Plants handling very small quantities, such as laboratories and hospitals, were exempt from regulation. In this study, changes in risk were examined for four medium-sized plating and paint manufacturing plants. Under the previous system, all four factories were judged as high-risk groups. In particular, the paint manufacturing plant A, which has an underground storage tank, received a medium risk like the plating plant C, although the possibility of a chemical accident was lower than that of other plants. However, in the changed system, all plants were changed to the low-risk group. In the Korean-style risk analysis, it is possible to see at a glance what is lacking in the plants, such as cooperation between local residents and local governments and the construction of safety facilities according to the type of accident scenario. The revised system is a reasonable regulation for medium business plants.

DEVELOPMENT AND JUSTIFICATION OF THE STRUCTURE OF ASSEMBLIES OF PYROLYSIS INSTALLATION FOR UTILIZATION OF MEDICAL WASTE

When developing a pyrolysis plant for the disposal of medical waste, the evaluation criteria were ergonomics, operational reliability, simplicity and manufacturability of its manufacture, as well as maintainability. In certain operating conditions, given the high degree of epidemiological danger, ensuring the minimum degree of operator contact with the most medical waste is an urgent task. Therefore, the most effective solution in the development of a simple and operationally reliable pyrolysis plant for waste disposal, provided the use of a special robotic loading device and a furnace design for incinerating medical waste. The application of the above developments made it possible to efficiently for the environment, in an automated mode, dispose of medical waste with a minimum degree of operator contact with the most medical waste, as well as with minimal economic and technological disposal costs. The creation of a simpler, highly reliable and safe pyrolysis plant for the disposal of medical waste with a low cost of their manufacture, increased maintainability and a high environmental safety degree necessitates special design and theoretical calculations. Plants for the disposal of medical waste are distinguished by a special nature of work, which is the excessive creation of high temperatures, for the complete neutralization (oxidation) of hazardous chemical compounds contained in medical waste. Therefore, when developing the pyrolysis plant itself for the disposal of medical waste, one should take into account the temperature difference at the inlet and outlet of the furnace itself for incinerating medical waste. In the process of developing and justifying the design of the units of the new installation for the disposal of medical waste, the following tasks were solved: - development of a schematic diagram of the units of the facility for the disposal of medical waste, reflects the relationship between the operating and operational parameters of the facility itself; - design calculations for the units of the facility for the disposal of medical waste; - theoretical studies of the influence of the operating and operational parameters of the installation for the disposal of medical waste in the technological process of disposal of medical waste.