Investigating a promising iron-doped graphene sensor for SO2 gas: DFT calculations and QTAIM analysis

Examination of a promising iron-doped graphene (FG) sensor for the sulfur oxide (SO2) toxic gas was done in this work at the molecular and atomic scales of density functional theory (DFT). The models were stabilized by performing optimization calculations and their electronic features were evaluated. Two models were obtained by relaxing each of the O or S atoms towards the Fe-doped region of surface. Energy values indicated higher strength for formation of the O@FG model in comparison with the S@FG model. The evaluated quantities and qualities of electronic molecular orbitals indicated the effects of occurrence of adsorption processes on the electronic conductivity property of FG as a required feature of a sensor material. As a consequence, the idea of proposing the investigated FG as a promising sensor of the hazardous SO2 gas was affirmed in this work based on the obtained structural and electronic features.

Analysis of Composite Scrubber with Built-In Silencer for Marine Engines

The International Maritime Organization (IMO) is strengthening regulations on reducing sulfur oxide emissions, and the demand for reducing exhaust noise affecting the environment of ships is also increasing. Various technologies have been developed to satisfy these needs. In this paper, a composite scrubber for ships that can simultaneously reduce sulfur oxide and noise was proposed, and the flow characteristics and noise characteristics were analyzed. For the silencer, vane type and resonate type were applied. In the case of the vane type, the effects of the direction, size, and location of the vane were analyzed, and in the case of the resonate type, the effects of the hole location and the number of holes were analyzed. The result shows that the length increase of the vane increased the average transmission loss and had a great effect, especially in the low frequency region. The transmission loss increased when the vane was installed outside, and the noise reduction effect was excellent when the vane was in the reverse direction. In the resonate type, increasing the number of holes is advantageous for noise reduction. The condition for maximally reducing noise in the range not exceeding 840 Pa, which is 70% of the allowable back pressure, is a vane length of 225 mm in the outer vane reverse type. The pressure drop under this condition was 777 Pa, and the average transmission losses in the low frequency region and the entire frequency region were 43.5 and 54.5 dB, respectively.

RESEARCH OF THE POSSIBILITY OF REDUCING THE CIRCULATION OF SULFUR OXIDE IN THE PRODUCTION OF WHITE CEMENT

The article discusses the possibility of reducing the circulation of sulfur oxide in the production of white cement by introducing alkaline potassium oxides K2O and sodium Na2O. A decrease in the circulation of sulfur oxide SO3 is achieved by increasing its yield in the clinker by transferring SO3 from a more sublimated compound of calcium sulfate CaSO4 to less sublimated potassium sulfates K2SO4 and sodium Na2SO4. Potassium and sodium oxides are introduced in the composition of carbonates and feldspar. The amount of introduced alkali oxides is controlled by the molar ratio A/S between sulfur oxide SO3 and alkaline oxides K2O and Na2O. It is shown that with the same molar ratio between sulfur oxide and alkaline oxides, the amount of SO3 removed with clinker depends on the ratio between potassium and sodium oxides. The higher the sodium oxide content, the more sulfur oxide comes out with the clinker and less remains to circulate in the kiln. The sublimation of sulfur oxide decreases from 70.5% - without the introduction of alkaline oxides, to 38,5 % at the maximum A/S ratio with the addition of potassium and sodium oxides in a ratio of 80:20 %. When potassium and sodium oxides are added in a ratio of 20:80%, the sublimation of sulfur oxide is reduced to 7,7 % at the same A/S ratio.

Research for the Optimal Flux-Cored Arc Welding Process of 9% Nickel Steel Using Multi Object Optimization with Solidification Crack Susceptibility

The environment of the global shipbuilding market is changing rapidly. Recently, the International Maritime Organization (IMO) has tightened regulations on sulfur oxide content standards for marine fuels and tightened sulfur oxide emission standards for the entire coastal region of China to consider the environment globally and use LNG as a fuel. There is a tendency for the number of vessels to operate to increase significantly. To use cryogenic LNG fuel, various pieces of equipment, such as storage tanks or valves, are required, and equipment using steel, which has excellent impact toughness in cryogenic environments, is required. Four steel types are specified in the IGG Code, and 9% Ni steel is mostly used for LNG fuel equipment. However, to secure safety at cryogenic temperatures, a systematic study investigating the causes of quality deterioration occurring in the 9% Ni steel welding process is required and a discrimination function capable of quality evaluation is urgent. Therefore, this study proposes a plan where the uniform quality of 9% Nickel steel is secured by reviewing the tendency of the solidification crack susceptibility among the quality problems of cryogenic steel to establish the criteria for quality deterioration and to develop a system capable of quality discrimination and defect avoidance.

Bottle Aging and Storage of Wines: A Review

Wine is perhaps the most ancient and popular alcoholic beverage worldwide. Winemaking practices involve careful vineyard management alongside controlled alcoholic fermentation and potential aging of the wine in barrels. Afterwards, the wine is placed in bottles and stored or distributed in retail. Yet, it is considered that wine achieves its optimum properties after a certain storage time in the bottle. The main outcome of bottle storage is a decrease of astringency and bitterness, improvement of aroma and a lighter and more stable color. This is due to a series of complex chemical changes of its components revolving around the minimized and controlled passage of oxygen into the bottle. For this matter, antioxidants like sulfur oxide are added to avoid excessive oxidation and consequent degradation of the wine. In the same sense, bottles must be closed with appropriate stoppers and stored in adequate, stable conditions, as the wine may develop unappealing color, aromas and flavors otherwise. In this review, features of bottle aging, relevance of stoppers, involved chemical reactions and storage conditions affecting wine quality will be addressed.

Air Pollutants and Greenhouse Gas Emissions Co-control Evaluation in the People’s Republic of China

Local air pollutants (LAPs), such as carbon monoxide, hydrocarbon, sulfur oxide, nitrogen oxide, ozone, and particulate matter, as well as greenhouse gas (GHG) emissions from the transport sector are rapidly increasing in the People’s Republic of China. Various measures to control LAPs have been implemented in the country, along with the adoption of strategies to mitigate GHG emissions. The connection between LAP and GHG emission control and reduction offers an opportunity to address both problems simultaneously. This paper presents a methodology that measures the benefits of co-control evaluation on mitigating LAP and GHG emissions. It highlights the methodology’s potential to help maximize measures and strategies that have significant co-control effects.

INVESTIGATION OF THE POSSIBILITY OF REDUCING THE CIRCULATION OF VOLATILE COMPOUNDS IN A ROTARY KILN OF A DRY PRODUCTION METHOD

The article considers a method of reducing the circulation of volatile compounds – sulfur, potassium, sodium compounds that can accumulate in the clinker burning system, circulate and lead to the formation of growths and deposits in the calciner, preheater and the loading part of the rotary kiln. The number of circulating compounds in the rotary kiln can be reduced by decreasing their degree of sublimation by converting them to less volatile compounds and removing these compounds from the firing system together with the clinker. In this case, it is necessary to provide a certain molar ratio between alkaline compounds and sulfur oxide, which depends on which compound will leave the burning system together with clinker. The introduction of potassium carbonate reduces the sublimation of sulfur oxide by 16 %, and sodium carbonate-by 45 %, due to the transfer of carbonates to less sublimable sulfates. The change of cement properties – setting time and strength, under the influence of compounds coming out with the clinker is shown. The start of setting of the cement paste is reduced by 41 %, the end of setting by 26 % with an increase in the ratio between alkaline compounds and sulfur oxide. The strength of cement in the initial period of hardening increases, and at the age of 28 days – decreases.

Development of the unit for testing the methods of remote computerized monitoring of environmental changes in the “IKI-Monitoring” center for collective use

The impact of hazardous waste on people and the environment from agricultural, industrial, military and mining activities form one of the most significant global environmental challenges. These wastes often include heavy metals, acid precipitates (sulfur oxide solutions), hydrocarbons, and other organic chemicals. Creation of the tools of the VEGA-Science service (http://sci-vega.ru/) to control the state of vegetation for the monitoring the impact of technogenic waste and dumps sources (TWDS) on the environment is the main objective of this work. To achieve this goal, proposals for the modernization and development of the VEGA-Science services have been defined to provide the organization and analysis of long-term variability of the vegetation cover caused by the influence of TWDS.