Engineering Commons^™

Alkynylation Of Benzaldehyde And Its R-Substituted Derivatives Based On Lithium Phenylacetylenide, Sanat B. Samatov, Odiljon E. Ziyadullayev, Abduvakhab Ikramov

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this research work is for the first time the synthesis of the corresponding acetylene alcohols based on the alkynylation reaction of isolated benzaldehyde and its R-substituted derivatives in the BuLi/TGF system. The study proposed the reaction stages for the synthesis of acetylene alcohols in the selected BuLi/TGF system, the influence of factors influencing the process, including temperature, reaction duration and nature selected solvents. The structure of the synthesized acetylene alcohols was confirmed by modern methods of physicochemical analysis (¹H NMR, ¹³C NMR). In addition, the effect of substituents in benzaldehyde and its R-substituted derivatives …

Numerical Calculation Of The Flame Spreading Over A Methane Hydrate Surface, Otabek Nigmatov, Oksana Ismailova

CHEMISTRY AND CHEMICAL ENGINEERING

The Methane Hydrate is expected as an energy source and is being as a medium distance transport means of natural gas alternative of LNG (Liquefied Natural Gas). During the natural gas transportation, fire accidents are concerned. In the present study, the flame spreading over a methane hydrate surface has been studied numerically as a function of hydrate surface temperature, T_s. When T_s = 173 K (-100℃), lower than the dissociation temperature (T_d = 183 K (-90℃)), the flame spreading speed is around 6.5 mm/s, while the flame spreading speed at T_s = 193 K (-80℃), …

Dft Study Of Quantum Chemical Parameters Of 4-Amino-2-Mercaptobenzimidazole And Their Tautomeric Forms, Dilnoza Rahmonova, Alisher Eshimbetov, Lobar Gapurova, Zuhra Ch. Kadirova, Shakhnoza Kadirova

CHEMISTRY AND CHEMICAL ENGINEERING

Coordination competing donor centers, electronic and geometric structures of the 4-amino-2-mercaptobenzimidazole ligand molecule were studied using quantum chemical calculation by the DFT / 6-31G method (d, p). It was shown that during the formation of the metal complex, the ligand is coordinated through the localized nitrogen atom of the imidazole ring. In this study, the total energies (Etot) of 4-amino-2-mercaptobenzimidazole (1) and its tautomeric forms (2 and 3) were calculated. And also, the energies of boundary molecular orbitals, the energy gap between boundary MOs (ΔE) and the distribution of the total charge on atoms and boundary orbitals were determined. In …

The Effect Of Hydrogen Peroxide And Potassium Amylxanthate On The Surface Properties Of Chalcocite And Enargite, Berdakh T. Daniyarov, Hajime Miki, Daminbek A. Ziyatov, Shahlo Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

The effect on the surface properties and floatability of chalcocite and enargite after oxidative treatment with hydrogen peroxide (H₂O₂) in the presence and absence of potassium amylxanthate (PAX) as a collector was studied. In this research, flotation tests were carried out on mixed and individual minerals. Oxidative treatment with hydrogen peroxide had a negative effect on the floatability of chalcocite and enargite. PAX adsorption analysis shows that enargite adsorbs PAX faster than chalcocite. Moreover, Fourier transform infrared spectroscopy analysis shows that PAX was adsorbed in the form of copper amylxanthate on chalcocite and enargite surfaces. In …

Influence Of The Amount Of Monoethanolamine On The Physicochemical Properties Of Aminolysis Products, Soxibjon A. Egamberdiyev, Muzaffar G. Alimukhamedov, Juraev Asror, Ravshan Adilov

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this paper is to investigate the process of aminolysis of secondary polyethylene terephthalate with monoethanolamine at low ratio. The effect of the amount of monoethanolamine on the physical and chemical properties of the aminolysis product of secondary polyethylene terephthalate was studied. With an increase of 1-4 moles of monoethanolamine obtained for synthesis (without the presence of a catalyst), it was observed that the number of amines in the aminolysis product increased from 324 to 503 mgKON/g, and the number of hydroxyls increased from 298 to 491 mgKON/g. The structure of the resulting bis(2-hydroxyethylene)terephthalamide was studied using IR …

Study Of The Structure Of Glass Ionomer Cements Developed Based On Glass System Sio2-Al2o3-Cao-Zno-P2o5-Caf2, Tatyana O. Nam, Mastura X. Aripova, Ripsime V. Mkrtchyan

CHEMISTRY AND CHEMICAL ENGINEERING

The goal was to study the structure of glass ionomer cements (GIC) developed on the basis of glasses of the SiO₂-Al₂O₃-CaO-ZnO-P₂O5-CaF₂ system. Glass powders with sizes less than 50 μm were sealed with a 40% solution of polyacrylic acid and after 72 hours, electron microscopic examination was carried out on a JSM-IT200 scanning microscope (JEOL, Japan). All samples demonstrate a cellular structure consisting of glass particles surrounded by glass elements that have entered into an acid-ion interaction with polyacrylic acid in a polymer matrix. GIC-4 and GIC-6 show the most …

Impact Of Sulfurization On Sputtered Bivo4 Thin Films, Shukur P. Gofurov, Dilbar T. Bozorova, Zuhra Ch, Kadirova, Oksana Ismailova

CHEMISTRY AND CHEMICAL ENGINEERING

The sulfurization method has been used to decrease the band gap of the BiVO₄ structure, reduce the recombination of electrons and holes, and increase the photoelectrochemical performance of this material. It has been observed that incorporation of sulfur into stoichiometric and V_rich BiVO₄ is variously affected changing of properties of the structure. Sulfurization can modify V_rich BiVO₄ structure rather than stoichiometric BiVO₄.

Development Of Clinker And Portland Cement Composition Based On Surkhondaryo Raw Materials, Salohiddin Ramazanov, Abdumalik Nabiyev, Mastura Aripova

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this research work is to develop clinker and Portland cement compositions based on Surkhandarya raw materials for the planned construction of a cement plant, as well as to study their physical and chemical properties. The compositions of clinkers, including limestone, clay from the Yolgizbulok deposit and slag from the Almalyk mining and metallurgical plant, were studied. The optimal clinker composition was selected, on the basis of which Portland cement was obtained. The optimal amount of gypsum addition was determined to achieve a cement stone strength of 43,5 MPa. The developed clinker composition will provide the planned enterprise …

Antibacterial Cerium-Containing Glazes For Ceramic Tiles, Ivan Levitskiy, Mastura Aripova, Mihail Dyadenko, Dar’Ya Kucherova, Artem Golub

CHEMISTRY AND CHEMICAL ENGINEERING

The results of research on the production of semi-fritted cerium-containing glazes used for ceramic tiles are presented.

A multicomponent raw material mixture based on dolomite, cerium dioxide CeO₂, aluminosilicate multicalcium frit and permanent components including feldspar, alumina and clay components (kaolin and refractory clay) is used to produce glazes.

The characteristics of the obtained coatings were studied: appearance, technological and physico-chemical properties, including antibacterial properties in relation to the strains of Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538. The influence of temperature parameters on the formation of glaze coatings, as well as their structure and phase …

Hydrological Model Of The Diyala River Watershed In Iraq Using Soil Water Assessment Tool, Ahmed Sagban Khudier, Ahmed Naseh Ahmed Hamdan

Al-Bahir

The motivation of the present study is to study and address the limitations imposed on hydrological models and the spatial and temporal distribution of streamflow in the Watershed Diyala River (WDR) from January 1996 to April 2023, which has an area of 25652 km2, which is considered an important source of water for central and southern Iraq, to enable decision-makers to make a future management plan for streamflow. To achieve this motivation, the SWAT model was used and fed by input data such as a Digital elevation model with a 30 m resolution, a soil map, the land use and …

Surface Treatments' Effects On The Capacitor's Dielectric Performance Under Electro-Thermal Stresses, Haider. M. Umran, Feipeng Wang

Karbala International Journal of Modern Science

Biaxial-oriented polypropylene (BOPP) films are characterized by unfavorable aging behavior because of their poor susceptibility to high temperatures, humidity, and high electric fields. This makes them unqualified to withstand harsh operating conditions, such as in capacitor applications. This study investigates the impact of annealing BOPP samples at 100 °C for five hours after fluorination at different times (15, 30, and 60 minutes) on their electrical and mechanical performance under electro-thermal stresses. Scanning electron microscope (SEM) images confirm that there is an increase in surface roughness and the formation of a dense layer of fluorine-containing groups monotonically with fluorination time. So, …

Electrochemical Syntheses Of Aryl-Substituted Benzothiophenes And Phenanthrenes Using Benzenediazonium Salts As The Aryl Radical Precursors, Li-Yuan Lan, Yang-Ye Jiang, Raymond Daniel Little, Cheng-Chu Zeng

Journal of Electrochemistry

Aryl-substituted benzothiophene and phenanthrene are important structural units in medicinal chemistry and materials science. Although extensive effort has been devoted to prepare these compounds and a variety of approaches have been developed to construct the 2-substituted benzothiophene core structure, environmental-friendly and efficient synthetic means are still desired. Based on our previous electrochemical Minisci-type arylation reaction with aryl diazonium salt as the aryl precursor, as well as the work from König’s group, herein, we described the use of paired electrolysis to achieve 2-aryl benzothiophenes and 9-aryl phenanthrenes employing benzenediazonium salts as the aryl radical precursors. Initially, 2-methylthiobenzendiazonium salt 1a and 4-methylbenzene …

Electrochemical Advanced Treatment Of Desulfurization Wastewater From Coal-Fired Power Plants, Ju-Cai Wei, Juan Yi, Xu Wu

Journal of Electrochemistry

Zero-emission of desulfurization wastewater is one of the main demands for coal-fired power plants. As typical high salinity wastewater, it is hard to purify the desulfurization wastewater from coal-fired power plants through traditional physicochemical treatment or biochemical treatment, e.g., COD and Cl^–. A high concentration of Cl^– ion in desulfurization wastewater restricts wastewater reuse and zero-emission. Electrochemical technology is an attractive method for high salinity wastewater zero-emission, which provides a versatile, efficient, cost-effective, easily automatable, and clean industrial process. For advanced treatment of effluent after triple box process treatment in power plants, this paper reports an electrochemical …

Electrocatalytic Cyclopropanation Of Active Methylene Compounds, Liang-Hua Jie, Hai-Chao Xu

Journal of Electrochemistry

The development of novel strategies to access cyclopropanes has become increasingly important due to the vital role of these three-membered ring structures in synthetic intermediates, natural products, and pharmaceuticals. Herein, we present an electrocatalytic method for the synthesis of cyclopropanes through intermolecular dehydrogenative annulation of active methylene compounds and arylalkenes. This electrochemical process requires no chemical oxidants, allowing for a speedy access to various functionalized cyclopropanes from inexpensive and readily available materials.

Response Mechanism Characteristics Of Mining-Induced Fault Activation, Sun Wenbin, Hao Jianbang, Dai Xianzheng, Kong Lingjun

Coal Geology & Exploration

In the process of coal mining, mining-induced stress perturbation is a key factor leading to fault activation, which is a primary challenge faced by safe coal mining. Fault activation is prone to induce geological disasters such as rock bursts and floor water inrushes of coal mines. Furthermore, it poses a serious threat to mining safety. Using the Flac^3D software for numerical simulations and similar material simulation experiments, this study established a model for faults’ stress-displacement responses under coal mining to analyze the mechanisms behind the evolution of fault structure zones in the process of coal mining. Key findings are …

Laws Of Changes In The Energy Of Gas Hydrate-Bearing Coals Under Different Confining Pressures And Saturations, Zhu Wei, Gao Xia, Zhang Baoyong, Wu Qiang

Coal Geology & Exploration

Gas hydration for the solidification of coal seams susceptible to outbursts is a novel technology used to prevent coal and gas outbursts by reducing gas pressure and enhancing coal strength. However, an unclear understanding of the failure characteristics and the energy dissipation law of gas hydrate-bearing coals under different confining pressures and saturations leads to the lack of a theoretical basis for the prevention of dynamic disasters such as field coal and gas outbursts in deep mines. Based on the deviatoric stress-strain curves obtained using triaxial compression tests, this study calculated and analyzed the laws of changes in energy of …

Preliminarily Exploring The Theories And Technologies For Coalbed Methane Production Using Horizontal Wells: Comparison Of Conditions For Coalbed Methane And Shale Gas Exploitation, Wang Hongyan, Duan Yaoyao, Liu Honglin, Zhao Qun, Chen Shangbin, Lu Haibing, Shi Zhensheng, Sun Qinping, Chen Zhenhong, Zhou Shangwen, Yang Mingwei, Wang Cong

Coal Geology & Exploration

Through 30 years of unremitting explorations, coalbed methane (CBM) wells in China have gradually transitioned from vertical to horizontal wells. However, the lack of basic theories on CBM production using horizontal wells is the main challenge to current CBM development. Compared to shales, coal seams exhibit heterogeneity and a minor presence of foliations and brittle minerals, hindering the formation of volumetric fracture networks. Nevertheless, the roofs and floors of coal seams have high sealing capacities and mechanical strength, creating excellent conditions for hydraulic fracturing. Some fractures in coals are filled with calcite, rendering acidification conducive to the improvement of reservoir …

Accumulation Characteristics And Exploration Prospects Of Deep Coalbed Methane In The Longtan Formation Of The Nanchuan Block On The Southeastern Margin Of The Sichuan Basin, Guo Tao, Jin Xiaobo, Wu Didi, Xie Fei, Liu Jinxian

Coal Geology & Exploration

Vertical well Y2 in the Nanchuan bloc on the southeastern margin of the Sichuan Basin has yielded daily production of natural flowing gas of 13000 m³, signifying a strategic breakthrough in deep coalbed methane (CBM) exploration on the margin. This study aims to systematically reveal the enrichment and high-yield patterns of CBM in the Nanchuan block. Using data on the regional geology, tests, assays, and production, this study investigated the accumulation characteristic and conducted exploration potential evaluation for deep CBM in the Nanchuan block from the perspective of the quality, pore and fissure characteristics, gas content, and fracability …

Fracture Propagation Mechanism In Directional Perforation And Hydraulic Fracturing Of Coal Seam Horizontal Wells, Pang Tao, Jiang Zaibing, Hui Jiangtao, Jia Bingyi

Coal Geology & Exploration

Horizontal well perforation and fracturing in complex coal-bearing strata are key to increasing coal seam permeability and enhancing gas extraction efficiency, with the formation structure and perforation location determining fracture propagation. Considering the characteristics of formation structure and perforation locations, a fracturing geological model is established. Based on the finite element method, a numerical model is constructed to study the effects of perforation location, formation conditions, and the difference between vertical stress and horizontal stress on fracture perforation. Engineering verification is conducted, and construction suggestions are proposed. Key findings are as follows: There are three scenarios for the perforation locations: …

An Intelligent Water Source Discrimination Method For Water Inrushes From Coal Seam Roofs In The Inner Mongolia-Shaanxi Border Region, Wang Hao, Sun Junqing, Zeng Yifan, Shang Hongbo, Wang Tiantian, Qiao Wei

Coal Geology & Exploration

Water hazard on the coal seam proof induced by high-intensity coal mining are increasingly prominent in the Inner Mongolia-Shaanxi border region. The effective, accurate water-source discrimination of the water inrushes is the key to water hazard prevention. This study investigated three typical mines in the Inner Mongolia-Shaanxi border region. To this end, principal component analysis (PCA) was employed to extract principal components from 80 groups of groundwater samples. Then, with inorganic indicators K⁺+Na⁺, Ca²⁺, Mg²⁺, Cl⁻, SO₄ ²⁻, HCO₃ ⁻ and TDS and organic indicators UV_{254 …}

Experimental Study Of The Thermal Cracking Mechanism Of Limestones During Burning, Zhang Weiqiang, Cao Zhicheng, Zhou Qizhong, Wang Zuoquan, Wu Yun

Coal Geology & Exploration

Spontaneous combustion of coal seams will cause different degrees of structural damage to surrounding rocks at different high temperatures, significantly altering their physical and mechanical properties and engineering geological effects. To delve into the structural evolution patterns of rocks during burning, this study investigated the limestones from the floor of a coal mine in Xuzhou. It conducted thermal cracking experiments under different temperatures, exploring the thermal cracking patterns of rocks on multiple scales. Furthermore, this study revealed the genetic mechanism of thermal cracking by combining numerical simulations and microstructure tests. Key findings are as follows: (1) The thermal cracking temperature …

Exploring The Detection Performance Of Different Array Configurations For Multi-Electrode Resistivity Method Tomography Using A 2.5d Finite Element Method, Zhao Rongchun, Lyu Yuzeng, Zhang Zhi, Wei Liuye, Pan Hongxu

Coal Geology & Exploration

Multi-electrode resistivity method is equipped with various electrode array configurations. Due to their different electrode arrangements, various electrode array configurations tend to exhibit significantly varying detection effects under different survey environments. Hence, to achieve satisfactory detection effects using high-resolution electrical resistivity tomography, it is necessary to explore the strategy for choosing appropriate array configurations targeting different objects in practical work. Given the high applicability of the method, its forward and inversion calculations remain a critical task. Based on the differential equations to be satisfied by the point source potential in a three-dimensional structure, this study derived the variational problem to …

Three-Dimensional Forward Modeling Using The Transient Electromagnetic Method Under Complex Terrains And The Analysis Of Terrain Effects, Qu Shaobo, Zhu Jiao, Jiang Zhihai, Li Maofei, He Zhilong

Coal Geology & Exploration

The ground-based transient electromagnetic method (TEM), with unique advantages, has been extensively applied for hydrogeological exploration in coal mines. However, in field exploration, complex terrains tend to cause variations in geometric shapes of transmitting sources and deviations in signals received, reducing exploration accuracy. Hence, by integrating theoretical analysis and numerical simulations with the analysis of actual terrain data, this study systematically investigated the response characteristics of electrical- and magnetic-source TEM fields under complex terrains. Using the vector finite-element electromagnetic forward modeling technique based on second-order backward Euler discretization, this study delved into the laws of influence of peak and valley …

Research On Path Planning Methods For Underground Roadheader Robots, Zhang Xuhui, Zheng Xili, Yang Wenjuan, Li Yuyang, Ma Bing, Dong Zheng, Chen Xin

Coal Geology & Exploration

In order to solve the problems of difficulty and low efficiency in the movement of robotic roadheaders under conditions of non-full-section roadways in coal mines, the characteristics of unstructured environments in coal mines and the motion characteristics of robotic roadheaders were analyzed, and a path planning method for robotic roadheaders based on deep reinforcement learning was proposed. The tunnel environment was constructed in real time using depth cameras, a virtual model for detecting roadheader-tunnel collisions was established, collision detection was performed in a virtual environment using the hierarchical bounding box method, and an obstacle avoidance strategy under the restrictions of …

Edge Detection Of Low Illumination Image In Cutting Unit Of Shearer, Jia Pengtao, Jin Luwei, Wang Bin, Guo Fengjing, Li Na

Coal Geology & Exploration

In this paper, a fractional differentiation-based edge detection algorithm named Lif is proposed to address the edge detection problems of missing edge and fuzzy details in the cutting unit of shearers working in low-light underground environments. First, the initial fractional mask operator was built using a larger detection template according to the Grünwald-Letnikov definition of the fractional derivative. Then, the weight coefficients at various positions of the mask operator were determined according to the theory of Pascal’s triangle, and the mask operator was extended to four different directions. Finally, the mask operator was convolved with the image, and the local …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Exploring Dynamic Parameters And Tooth Structure Of Self-Propelled Borehole Repairing Drill Bits, Liu Yong, Li Yang, Wei Jianping, Yuan Yongwang, Dai Shuo, Li Linyu

Coal Geology & Exploration

Self-propelled borehole repairing drill bits provide an effective technique for repairing long boreholes that have failed. In order to further improve the borehole repair speed and gas drainage efficiency, based on the theory of jet recoil, the relationship between the jet recoil force and nozzle parameters was analyzed, and a theoretical model was established for rotational mechanics of self-propelled borehole repairing drill bits. Subsequently, the coal-breaking processes of drill bits with different tooth structures were simulated using LS-DYNA, the failure modes in coal mass broken by cutting teeth and the rules of variation in the volume of coal broken by …

Prediction Of Mine Water Inflow Along Mining Faces Using The Ssa-Cg-Attention Multifactor Model, Ding Yingying, Yin Shangxian, Lian Huiqing, Liu Wei, Li Qixing, Qi Rongrong, Bu Changsen, Xia Xiangxue, Li Shuqian

Coal Geology & Exploration

Predicting mine water inflow plays an important role in ensuring mine safety, optimizing resource allocation, and improving work efficiency. This study aims to improve the accuracy and stability of the predicted mine water inflow. Given their strong correlations with water inflow, borehole water level and microseismic energy were chosen as multifactor characteristic variables. Using these variables, this study developed the SSA-CG-Attention multifactor prediction model for mine water inflow along mining faces. The new model extracted effective nonlinear local features of data utilizing a new network structure, which was formed by integrating a convolutional neural network (CNN) based on the time …

Intelligent Identification Method For Overburden Three Zones Of A Goaf, Li Jianwen, Zhao Wen, Wu Zhenkun, Xu Xiaobing, Wang Qingtao, Duan Longchen

Coal Geology & Exploration

In this paper, an intelligent identification method was proposed to ascertain overlying strata failure types and fracture development in the overlying strata of a goaf, and identify three zones (sagging zone, fractured zone and caving zone) quickly and accurately. This method is expected to be a basis in later development of goaf treatment plans. A coal mine goaf in Shandong Province was introduced for case study, where the Bayesian Online Changepoint Detection (BOCD) algorithm was employed to analyze the changes and response characteristics of the drilling fluid loss and drilling rate over the drilling process at the boundaries of three …

Mechanism And Application Of Cross-Interface Fracturing For Permeability Enhancement Through The Roof Blasting Of Tectonic Coal Seams, Gao Kui, Wang Youwei, Qiao Guodong, Tian Yu, Fu Shigui

Coal Geology & Exploration

Deep coal mining is challenging due to deteriorating geological conditions. After undergoing multiphase tectonic movements, primary coals have evolved into soft tectonic coal seams with low permeability and high gas content, complicating drilling in coal seams. In this case, the blasting-induced fractures are not well-developed and are prone to be re-compacted. So far, no fundamental breakthrough has been achieved in the key technology of fracturing for permeability enhancement technology through the roof blasting of tectonic coal seams. Given this, this study established test models for similar simulation tests and numerical analysis on the roof blasting of coal seams. By monitoring …