Leakage Of Substances Research Articles

ASSESSMENT OF DANGER FACTORS IN CASE OF ACCIDENTS OF RAILWAY TANKS WITH LIQUEFIED HYDROCARBON GASES

Introduction. Human security is the most important aspect of the functioning of society. Accidents during the transportation of liquefied hydrocarbon gases are one of the most dangerous events on rail transport. A significant part of the known accidents in the case of transportation of liquefied gas refers to flashes and explosions, which are the most dangerous in terms of safety of personnel, the population adjacent to the accident site and the environment. Railway accidents are often the result of the derailment. One of the causes of failure can be technical defects, often associated with improper maintenance. Also, errors of the railway control staff (human factor) or technical problems of the signal system can lead to train collisions.Aim. The purpose of the work is to assess the dangerous factors of accidents during the transportation of liquefied gas by rail.Results. Liquefied hydrocarbon gases are substances that require special precautions during transportation. The scale of traffic is the basis for the emergence of a relatively high level of risk of emergencies. During an emergency depressurization of the tank, an explosion of the gas mixture is most likely to occur if there is an instantaneous ignition as well as flare burning with non-instantaneous inflammation of liquefied propane. Accidents on railways with subsequent leakage of substances from the tank in rare cases occur in the horizontal position of the tank, more often there is a derailment, overturning of several tanks from the railway tracks, while the emergency tank is located at an angle to the horizon. It was calculated the volume and mass of liquid propane that will leak when the tank is tilted. Calculations of the intensity of warm radiation and thermal doses at a distance of placement of people in case of ignition of contents of the tank both in horizontal and in inclined position are carried out.Conclusions. Based on the calculation of the intensity of thermal radiation (thermal doses) in case of fire of the tank contents both in a horizontal and inclined position. We established that people on the platform and in the settlement will be in the zone of dangerous fire and can get burns of various degrees.

Antibacterial activity and mechanism of phillyrin against selected four foodborne pathogens

The antibacterial activity of phillyrin on Escherichia coli ATCC8739 (E. coli ATCC8739), Bacillus subtilis BS08, Staphylococcus aureus ATCC6538 (S. aureus ATCC6538) and Salmonella ATCC14028 was determined by filter paper method. The minimum inhibitory concentration (MIC) of the four tested bacteria was investigated by plate coating method to evaluate antibacterial ability. The antibacterial mechanism was further investigated by measuring growth curve, electric conductivity, nucleic acid content, Na+/K+-ATPase activity and polyacrylamide gel electrophoresis (SDS-PAGE). The results indicated that phillyrin had antibacterial effects and the MICs against Escherichia coli ATCC8739, Bacillus subtilis BS08, Staphylococcus aureus ATCC6538 and Salmonella ATCC14028 were 2.15, 3.16, 3.02 and 3.40 μg/mL respectively, and the antibacterial effect on Escherichia coli ATCC 8739 was more significant (p< 0.05) than that on other bacteria. Scanning electron microscopy (SEM) indicated that phillyrin destroyed the morphology of the cells and the cells ruptured. The leakage of intracellular substances led to an increase in nucleic acid content and an increase in electric conductivity in the bacterial suspension; SDS-PAGE analysis indicated that phillyrin could inhibit protein synthesis; in addition, phillyrin could reduce Na+/K+-ATPase activity. Therefore, phillyrin had obvious antibacterial ability and inhibited the expression of bacterial proteins by destroying the cell membrane structure, resulting in the death of the cells.

Quantitative proteomic analysis provides insight into the survival mechanism of Salmonella typhimurium under high-intensity ultrasound treatment

The survival mechanism of Salmonella treated with high-intensity ultrasound (HIU) should be explored to further enhance the bactericidal efficacy of HIU. In this study, culturable Salmonella was reduced by applying HIU. Electron microscope imaging revealed that HIU caused the disintegration of cell structure and leakage of intracellular substances. For the Salmonella after the HIU treatment, key enzymes of the tricarboxylic acid [TCA] cycle were significantly downregulated, which led to a reduced ATP content (45.25%–75.00%), although ATPase activity was augmented by 33.82%–60.64% in the Salmonella. Accordingly, surviving Salmonella could have tolerated the stress of HIU by upregulating their environmental sensing (two-component system), chemotaxis (bacterial chemotaxis), substance uptake (ABC transporter), and ATP production (oxidative phosphorylation). Therefore, synergistically blocking the ATP production, signal transduction, or substance intake of Salmonella offer promising potential strategies to improve the bactericidal effect of HIU in industrial food processing.

Evaluation of the Inhibitory Effects of Wuyiencin, a Secondary Metabolite of Streptomyces albulus CK-15, Against Sclerotinia sclerotiorum InVitro.

Sclerotinia sclerotiorum (Lib.) de Bary, a destructive fungal pathogen with an extensive host range, causes various diseases with the potential to cause huge economic losses to crops worldwide. Streptomyces species produce secondary metabolites with variable structures and biological activities that offer possible control methods for crop diseases. Herein, we evaluated the inhibitory effects of wuyiencin, a secondary metabolite of Streptomyces albulus CK-15, against S. sclerotiorum. The results showed that wuyiencin markedly inhibited mycelial growth and germination and the formation of sclerotia. It also increased cell membrane permeability, resulting in leakage of intracellular substances in pathogen mycelia. Wuyiencin markedly decreased oxalic acid content and the activities of polygalacturonase and pectin methyl-galacturonic enzymes. Moreover, it downregulated Nox1, ITL, pph1, Caf1, and sca1, all genes related to growth and infection. Lesions were smaller and less pronounced on soybean (Glycine max [L.] Merr.) leaves pretreated with wuyiencin invitro, and the inhibition rate reached 78.36%. The results suggest that wuyiencin holds promise for the management of diseases caused by S. sclerotiorum, and the findings provide clues on the mechanism of action.

A Novel Antibacterial Component and the Mechanisms of an Amaranthus tricolor Leaf Ethyl Acetate Extract against Acidovorax avenae subsp. citrulli.

The aim of the present investigation was to determine the active ingredients in Amaranthus tricolor L. leaves and develop a biological pesticide. Organic solvent extraction, column chromatography, liquid chromatography, ODS-C18 reverse elution, Sephadex LH-20 gel filtration, H spectrum, and C spectrum were used to isolate the pure product for an assessment of the agricultural activity and bacteriostatic mechanisms. The results showed that the activity of the crude extract following carbon powder filtration was 1.63-fold that of the non-filtered extract. Further isolation was performed to obtain two pure products, namely, hydroxybenzoic acid (HBA) and benzo[b]furan-2-carboxaldehyde (BFC), and their molecular formulas and molecular weights were C7H6O3 and 138.12, and C9H6O2 and 146.12, respectively. Our study is the first to determine that HBA has bacteriostatic activity (MIC 125 μg/mL) and is also the first to isolate BFC from A. tricolor. The ultrastructure observation results showed that HBA caused the bacteria to become shriveled, distorted, and deformed, as well as exhibit uneven surfaces. After HBA treatment, 70 differentially expressed metabolites were detected in the bacteria, of which 9 were downregulated and 61 were upregulated. The differentially expressed metabolites were mainly strigolactones, organic acids and derivatives, fatty acids, benzene and substituted benzene derivatives, amino acids and associated metabolites, and alcohols and amines. Among all of the downregulated differentially expressed metabolites, MEDP1280 was the most critical, as it participates in many physiological and biochemical processes. The enrichment analysis showed that the differentially expressed metabolites mainly participate in tyrosine metabolism, biosynthesis of amino acids, cysteine and methionine metabolism, and arginine and proline metabolism. Additionally, HBA was found to disrupt cell membrane permeability and integrity, causing the leakage of substances and apoptosis. The physiological and biochemical test results showed that HBA could increase the pyruvate levels in bacteria but could decrease the activities of respiratory enzymes (malate dehydrogenase (MDH) and NADH oxidase) and antioxidant enzymes (superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX)). Inverse molecular docking was used to study the binding between HBA and respiratory and antioxidant enzymes. The results showed that HBA could bind to MDH, NADH oxidase, SOD, and GSH-PX, suggesting that these enzymes may be the effector targets of HBA. Conclusion: The optimal active ingredient in A. tricolor that can inhibit Acidovorax avenae subsp. citrulli was identified as HBA. HBA mainly disrupts the cell membrane, damages the metabolic system, and inhibits respiration and antioxidant enzyme activity to control bacterial growth. These results provide a reference for the further development of biological pesticides.

Investigation of parameters of leakage of toxic and explosive substances and gases under the action of high pressure from tanks of the special purpose during

Tanks for the storage of oil products and toxic substances in warehouses are the main ones. They can be in the form of separate tanks or a group of tanks. The most widespread are vertical steel tanks with a stationary roof that a placed in open areas. The tanks heat up, and the intensity of evaporation of the oil product increases in case of fire. If there is a permanent roof, the pressure in the tank will increase. If the capacity of the breathing valves is less than the intensity of evaporation then there is a risk of explosion. Explosions in the tank often lead to the separation of the bottom, and the side cylindrical surface and the roof fly away instantly, spilling oil on neighboring tanks and the territory of the tank’s park. Then the combustion area increases intensively. The destruction of the integrity of the tank, due to the separation of the bottom, contributes to temperature and power stresses, the value of which increases with increasing temperature of their heating and increasing pressure, respectively. The values of temperature stresses are added to the power stresses caused by pressure, and when the critical value is reached, destruction occurs.&#x0D; In the article by the method of mathematical modeling using the laws of thermodynamics and mechanics of liquids and gases, analytical dependences for research of parameters of leakage of toxic substances and gases at action of high pressure from capacities at their storage are received. Saint-Venant’s principle was used to model the gas flow rate process. The dependence of the duration of gas leakage from special purpose tanks at the change of the area of the emergency hole and the pressure drop is obtained. The obtained results allow determining the velocity and mass flow rate of the gas depending on the area of the hole, the time flow, and the difference of pressure. Therefore, the task of research the emergency situations of engineering cylindrical tanks under the influence of temperature and pressure, which leads to the spillage of toxic substances and gassiness is actual. The researches results are presented graphically.

Antibacterial and Antibiofilm Effect of Ultrasound and Mild Heat Against a Multidrug-Resistant Klebsiella pneumoniae Stain Isolated from Meat of Yellow-Feathered Chicken.

Klebsiella pneumoniae is an important foodborne pathogen with high biofilm-forming ability, which is continuously detected in food products in recent years. The antibacterial and antibiofilm activities and mechanism of ultrasonication in combination with heat treatment against K. pneumoniae were studied. K. pneumoniae planktonic and biofilm cells were treated with ultrasound (US), mild heat treatment (HT50, HT60, and HT70), and combinations of US and mild heat treatment (UH50, UH60, and UH70) for 5, 10, 20, 30, and 60 min. Results showed that the combination of US and mild heat treatment was more effective in inactivating K. pneumoniae planktonic and biofilm cells than the single treatment by counting viable bacteria. In addition, confocal laser scanning microscopy, scanning electron microscopy, and analysis of leakage of intracellular substances have revealed that the combination treatment effectively damaged the integrity of bacterial cell membrane and increased cell permeability, which led to the quick release of adenosine triphosphate (ATP) and macromolecular substances of nucleic acids and proteins. Moreover, the activities of respiratory chain dehydrogenase in planktonic and biofilm cells significantly decreased after UH treatment. The results indicated that ultrasonication and mild heat treatment had a synergistic effect on the inactivation of K. pneumoniae planktonic and biofilm cells by damaging the cell membrane and inhibiting intercellular cell respiration.

The Bactericidal Efficacy and the Mechanism of Action of Slightly Acidic Electrolyzed Water on Listeria monocytogenes' Survival.

In the present work, the bactericidal efficacy and mechanism of slightly acidic electrolyzed water (SAEW) on L. monocytogenes were evaluated. The results showed that the strains of L. monocytogenes were killed completely within 30 s by SAEW whose available chlorine concentration (ACC) was higher than 12 mg/L, and it was confirmed that ACC is the main factor affecting the disinfection efficacy of SAEW. Moreover, our results demonstrated that SAEW could destroy the cell membrane of L. monocytogenes, which was observed by SEM and FT-IR, thus resulting in the leakage of intracellular substances including electrolyte, protein and nucleic acid, and DNA damage. On the other hand, the results found that SAEW could disrupt the intracellular ROS balance of L. monocytogenes by inhibiting the antioxidant enzyme activity, thus promoting the death of L. monocytogenes. In conclusion, the bactericidal mechanism of SAEW on L. monocytogenes was explained from two aspects including the damage of the cell membrane and the breaking of ROS balance.

Heptanal inhibits the growth of Aspergillus flavus through disturbance of plasma membrane integrity, mitochondrial function and antioxidant enzyme activity

Fungal contamination poses a threat to agriculture, food production and human health, and a safe and effective method to limit fungal contamination is still needed. In this study, the inhibitory potency of heptanal, a natural volatile chemical, against Aspergillus flavus growth was evaluated, and its mechanism of action was explored. The minimum inhibitory concentrations (MICs) of heptanal vapor fumigation and liquid contact culture were 0.085 and 0.8 μL/mL, respectively. A total of 79 significant differentially abundant metabolites, including 37 upregulated and 42 downregulated ones, were identified in A. flavus mycelia after exposure to 0.8 μL/mL heptanal for 6 h. Metabolomics analysis revealed that heptanal had destructive effects on plasma integrity and mitochondrial function in mycelia. Biochemical analysis confirmed that heptanal caused intracellular substance leakage and resulted in reduced intracellular ATP content, reactive oxygen species (ROS) accumulation, and lower mitochondrial dehydrogenase and ATPase activities. Evaluation of the control efficacy of heptanal fumigation on wheat grain under simulated storage conditions revealed that 225.0 μL/L heptanal vapor could inhibit A. flavus growth under 19% moisture. These results provide insights into the antifungal mechanism of heptanal against A. flavus growth as a promising bio-preservative.

Characterization of Thermal-Runaway Particles from Lithium Nickel Manganese Cobalt Oxide Batteries and Their Biotoxicity Analysis

Thermal runaway is one of the main causes of lithium-ion battery failure or even explosion, accompanied by the leakage of toxic substances into the environment. In the present work, a severe therma...

Inactivation kinetics and cell envelope damages of foodborne pathogens Listeria monocytogenes and Salmonella Enteritidis treated with cold plasma

In recent years, more attention has been paid to the application of cold plasma (CP) in eliminating foodborne pathogenic bacteria. This work investigated CP effects on inactivation kinetics and cell envelopes of Listeria monocytogenes (L. monocytogenes) and Salmonella Enteritidis (S. Enteritidis). Bacterial suspensions were treated with dielectric barrier discharge atmospheric CP at 75 kV for different treatment time. Three regression models were tested for estimating inactivation kinetics. Reactive species generated in plasma, the appearance and integrity of bacterial cells, the activity and secondary structure of enzymes in the cell envelope, and molecular docking, were measured for evaluating the envelope damages. Results indicated that Log-linear model was suitable for L. monocytogenes and the Weibull model was suitable for S. Enteritidis. S. Enteritidis was more sensitive to short-lived reactive species (such as OH radicals) in plasma than L. monocytogenes, and the cell envelope of S. Enteritidis was more severely damaged (the increased membrane permeability and leakage of intracellular substances) after plasma treatment. Interestingly, compared with S. Enteritidis, the decrease in the activity of enzymes existing in the cell envelope of L. monocytogenes did not contribute significantly to the death of bacteria. Molecular docking further suggested that the decrease in the enzyme activity might be due to the modification of the enzyme, by the interaction between reactive species in plasma (H2O2) and amino acid residues of the enzyme through the hydrogen bond.

Inactivation of fungal spores in water with peracetic acid: Efficiency and mechanism

In recent years, peracetic acid (PAA) has been widely used in sewage disinfection due to its strongly sterilizing capacity and less toxic by-products production. However, there was no studies on the inactivation kinetics and mechanism of fungal spores in water by PAA as well as their regrowth. The inactivation efficiency and mechanism of Aspergillus niger and Aspergillus flavus by PAA was illustrated in this study. The results showed that the inactivation of fungal spores fitted to the delayed Chick–Watson model well. The inactivation rate constants were 0.038 and 0.033 L mg−1 min−1, respectively. The effects of pH value and humic acid concentration on the inactivation efficiency were negative and the effect of temperature was positive, while the effect of HCO3− and Cl− on the disinfection of fungal spores could be negligible. The results of flow cytometric measurements, morphological observation and the leakage of intracellular substances indicated that the inactivation of fungi by PAA was attributed to the penetration of cell membranes rather than the damage of cell membranes. PAA was found to be effective for the inactivation of fungal spores, but was less effective than several traditional disinfectants (Cl2, ClO2) under the same condition. Furthermore, the regrowth of fungal spores after disinfection with PAA was also evaluated. The regrowth of fungal spores that after 1–3 log inactivated in the R2A medium within 5 days was observed, but the regrowth of completely inactivated fungal spores in R2A and in trace element solution was negligible. This study provides the valuable information for the application of PAA in the control of fungal pollution.

Emission source tracing based on bionic algorithm mobile sensors with artificial olfactory system

AbstractThe leakage of hazardous chemicals and toxic volatile substances in the atmosphere may cause serious consequences such as explosion and poisoning. To identify the unknown leakage locations and gas compositions, a mobile robot system to trace the leak source in the outdoor was investigated. First, two bionic searching algorithms, Zigzag and Silkworm algorithms, were tested with outdoor experiments for locating the leak source. The results showed that the locating errors of these two algorithms were within 0.5 m in 10 by 20 m search space, but the failing ratio of Zigzag and Silkworm algorithm was still high (about 40–50%). Therefore, an improved tracing algorithm combining the Silkworm and Zigzag algorithm, called as zigzag–Silkworm algorithm, was proposed. Compared with Silkworm and Zigzag algorithms, zigzag–Silkworm algorithm had a higher success ratio of 80% in outdoor source tracing tests, and the searching efficiency was enhanced, the efficiency parameter L: L0 has improved from 2.58 for Silkworm and 2.66 for Zigzag to 2.17 for zigzag–Silkworm. Then, in order to identify the composition of the leaked gases during the source tracing, an artificial olfaction system (AOS) based on the gas sensor array and support vector machine was set on the mobile robot. The test results in the source tracing experiments with ammonia and ethanol emissions indicated that the recognition accuracy of emission gases reached to 99% with AOS equipped on the robot. Therefore, the mobile robot system equipped with the zigzag–Silkworm algorithm and the AOS is feasible to trace the leakage source and identify the emission composition in the outdoor leakage event with good performance in efficiency and accuracy although some underlying problems still need to be addressed in future work.

Removal of Micropollutants by Ozone-Based Processes

Micropollutants and emerging substances pose a serious problem to environmental sustainability and remediation, due to their widespread use and applications in everyday life. This group of chemicals is diverse but with common toxic and harmful properties. Their concentration in the environment is often very low; however, due to their recalcitrant nature, they are persistent in air, water, and soil. From an engineering point of view, the challenge is not straightforward. It is difficult to remove these contaminants from complex mixtures of substances by conventional methods used in wastewater and drinking water treatment. Ozonation and ozone-based AOPs are accepted processes of degradation of resistant substances or at least enhancement of their biodegradability. The aim of this review paper is to present research trends aimed at solving problems in the research and application of ozone-based processes in the removal of micropollutants from wastewater, thus preventing leakage of harmful substances into surface water, soil, and groundwater and facilitating the reuse of wastewater. Priority substances, micropollutants and emerging pollutants, as well as processes and technologies for their transformation and elimination, are briefly specified. Results obtained by the authors in solving research projects that were aimed at eliminating selected micropollutants by ozonation and ozone-based AOPs are also presented. This review focuses on selected alkylphenols, petroleum substances, and organochlorine pesticides.

Моделювання просторово часової оцінки територіального ризику при аваріях під час транспортування залізницею небезпечного вантажу

Моделювання просторово часової оцінки територіального ризику при аваріях під час транспортування залізницею небезпечного вантажу

Risk analysis of gas leakage in gas pressure reduction station and its consequences: A case study for Zahedan

Industrial accidents have increased the importance of dealing with the risks of toxic exposure, fire and explosion. Despite the measures taken in the chemical industry to prevent accidents, the accidents occur often due to human error or process faults during repairs. Although several studies have been conducted on the accidents in the process industry, no research has modeled the risks caused by the leakage of toxic substances in the gas pressure reduction station. The consequences of gas leak and fire in Zahedan's gas pressure reduction station were investigated in Iran. This research aims to determine the safe range of the station and observe the safety measures required for the gas pressure reduction station in Zahedan. For modelling gas leak and fire, the ALOHA software was used to display the threat zone. In this research, with respect to the environmental data, the desired scenario was modeled. The results, based on two scenarios of gas leak and fire in both hot and cold seasons, indicate that the gas leak scenario in hot seasons and the fire scenario in cold seasons influence a larger region.

Environmental impact of emerging contaminants from battery waste: A mini review

The widespread consumption of electronic devices has made spent batteries an ongoing economic and ecological concern with a compound annual growth rate of up to 8% during 2018, and expected to reach between 18% and 30% to 2030. There is a lack of regulations for the proper storage and management of waste streams that enables their accumulation in open settings and the leakage of hazardous substances into the environment on landfill settings. In addition, recent trends in battery manufacture dictate the use of emerging materials like ionic liquids for electrolytes and nanostructures for cathodes to enhance their energetic properties and lifespan. The full impact of novel battery compounds on the environment is still uncertain and could cause further hindrances in recycling and containment efforts. Currently, only a handful of countries are able to recycle mass-produced lithium batteries, accounting for only 5% of the total waste of the total more than 345,000 tons in 2018. This mini review aims to integrate currently reported and emerging contaminants present on batteries, their potential environmental impact, and current strategies for their detection as evidence for policy and regulation.

Inhibition mechanism and antibacterial activity of natural antibacterial agent citral on bamboo mould and its anti-mildew effect on bamboo.

Bamboo, a natural material, has been widely used in the fields of decoration, architecture and furniture. However, bamboo is easy to mildew and lose its use value. In this paper, the inhibition mechanism and antibacterial activity of a natural antibacterial agent citral on bamboo mould and its anti-mildew effect on bamboo were studied. The results showed that citral could change the shape of mycelium, destroy the integrity of mycelium structure, cell wall and cell membrane structure, thereby causing leakage of nucleic acids, proteins and other substances in the cell, as well as destroy the pH balance of the inside and outside of the cell, to inhibit or kill mould. When the concentration of citral is 100 mg ml−1, the antibacterial rates of citral against Penicillium citrinum (PC), Trichoderma viride (TV), Aspergillus niger (AN) and a hybrid fungi group comprising PC, TV and AN (Hun) were more than 100%. However, compared with the direct effect of citral on mould, the antibacterial property of bamboo treated with citral was significantly reduced, the mildew proof effect can be achieved only if the concentration of citral to treat bamboo is increased to more than twice the concentration of citral directly acting on mould.

A Study on Development of Damage Impact Distance Calculation Formula for Accident Response and Prevention in case of Leakage of Substances Prepared for Evacuation of Residents in Chungju

A Study on Development of Damage Impact Distance Calculation Formula for Accident Response and Prevention in case of Leakage of Substances Prepared for Evacuation of Residents in Chungju

Blue light promotes bactericidal action of plasma-activated water against Staphylococcus aureus on stainless steel surfaces

The effects of blue light on the promotion of the bactericidal action of plasma-activated water (PAW) against Staphylococcus aureus by inducing the photolysis of staphyloxanthin (STX) were examined. A light-emitting diode (466 nm) and atmospheric-pressure plasma were applied. The degradation of STX pigments extracted through pure methanol was facilitated by increased dosage of blue light (30, 60, 90, and 150 J/cm2). After combined treatment with blue light (150 J/cm2) and PAW (10 min), the surviving population of S. aureus in liquid decreased by 2.70 log CFU/mL, which was about 40 times greater than that of single PAW treatment. Blue light (150 J/cm2) treatment induced leakage of intracellular substances, indicating potential damage to the cell membrane, which was also confirmed as an increase in the SYTOX™ green fluorescence signal. The synergistic bactericidal effect of blue light and PAW was also observed for S. aureus attached to the surface of stainless steel.