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Articles 1261 - 1290 of 16385

Full-Text Articles in Materials Science and Engineering

Industrial Design And Economic Analysis Of Steel Box Girder Bridge With Conventional Span, Cui Bing, Chen Kun Feb 2025

Industrial Design And Economic Analysis Of Steel Box Girder Bridge With Conventional Span, Cui Bing, Chen Kun

Journal of China & Foreign Highway

To improve the industrial construction level of steel bridges,a prefabricated continuous steel box girder bridge was designed in this study,which is suitable for bidirectional four lanes and six lanes with spans ranging from 40 m to 80 m.The overall dimensions and local structures of the steel box girder bridge were determined according to the specifications and engineering experience,and the load-bearing capacity was checked.Modular industrial products were designed by defining the vertical and horizontal modular divisions for the steel box girders,resulting in 21 standardized modular components.Based on the concept of life cycle,an economic analysis of the prefabricated steel box girder bridge …

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Mechanism Of Mud Pumping On Plateau Highway Under Traffic Loads And Its Treatment Strategy, Zhang Junhui, Chen Zhide, Gao Feng, Na Qicai, Ma Pengfei, Xiao Lin Feb 2025

Mechanism Of Mud Pumping On Plateau Highway Under Traffic Loads And Its Treatment Strategy, Zhang Junhui, Chen Zhide, Gao Feng, Na Qicai, Ma Pengfei, Xiao Lin

Journal of China & Foreign Highway

The dynamic hydraulic response and particle migration of subgrade structures under traffic loads are fundamental to reveal the formation and development mechanisms of mud pumping.The driving mechanism of fine particle migration in the mud pumping state was explored by conducting laboratory tests on layered gravel-sandy silt columns under dynamic loads.The results show that the slurry sloshing causes alternating positive and negative pressure gradients within the gravel layer.This oscillating pressure gradient enhances the pore permeability in the underlying sandy silt layer,providing the necessary hydrodynamic conditions for fine particle migration.Fine particle migration increases the slurry turbidity to a stable value.Upon the removal …

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Risk Zoning Of Hazards Along Highways To Xizang Based On Information Model, Liu Weimin, Guo Guanmiao, Cai Qing ’E, Yu Xueyong, Dong Xiaobo, Chen Peicong Feb 2025

Risk Zoning Of Hazards Along Highways To Xizang Based On Information Model, Liu Weimin, Guo Guanmiao, Cai Qing ’E, Yu Xueyong, Dong Xiaobo, Chen Peicong

Journal of China & Foreign Highway

The frequent occurrence of hazards along the highways in the Qinghai ‒ Xizang Plateau seriously affects road traffic and threatens the security of lives and property of the people.Conducting a risk zoning assessment of hazards along the highways to Xizang is crucial to enhancing hazard prevention and mitigation.This paper summarized the regional geological environment and development patterns of hazards along the highways to Xizang and analyzed the overall performance of highway traffic operations.On this basis,the Xinjiang‒Xizang Highway was taken as the research object,and the evaluation factors were selected based on the regional geological environment and the main controlling factors of …

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Influence Of Urease-Induced Calcium Carbonate Precipitation On Frost Heave Characteristics Of Saline Soil, Li Jue, Wen Zili, Liu Zhengnan Feb 2025

Influence Of Urease-Induced Calcium Carbonate Precipitation On Frost Heave Characteristics Of Saline Soil, Li Jue, Wen Zili, Liu Zhengnan

Journal of China & Foreign Highway

This study investigated the impact of the soybean urease-induced calcium carbonate precipitation (SICP ) technique on frost heave characteristics of saline soil,specifically addressing the frost heave in saline soil used as a subgrade.The relationships between compaction degree,moisture content,volume ratio of the reaction liquid,and curing temperature with the frost heave rate of treated soil were explored.The results show that SICP significantly reduces the frost heave rate of soil samples by over 28%,with the most noticeable improvement occurring under conditions of higher compaction degree and lower moisture content.Additionally,the increased volume ratio of reaction liquid enhances reaction efficiency,while lower curing temperatures are crucial …

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Prediction And Evaluation Of Road Service Performance In Cold Regions Based On Uncertainty Quantification Theory, Liu Yuanyuan, Si Junling, Zheng Hao, Ren Daoju, Fan Shaobing, Quan Lei Feb 2025

Prediction And Evaluation Of Road Service Performance In Cold Regions Based On Uncertainty Quantification Theory, Liu Yuanyuan, Si Junling, Zheng Hao, Ren Daoju, Fan Shaobing, Quan Lei

Journal of China & Foreign Highway

In cold regions,road service performance is influenced by various nonlinear dynamic factors under complex hydrothermal environments and freeze-thaw cycles.Traditional empirical and mechanical models exhibit significant limitations in comprehensively considering the impacts of complex environments and conducting quantitative analyses.This study proposed a method to predict and assess the service performance of constructed roads in cold regions.The method integrated deep neural networks with uncertainty quantification theory,addressing the inadequacies of existing models in adapting to complex environments and analyzing multiple influencing factors.By utilizing data from Montana road sections in the LTPP database,the study employed deep neural networks to predict the international roughness index …

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Permanent Deformation Prediction Model Of Subgrade Soil Under Freeze-Thaw Cycles Based On Lstm And Transformer, Zhang Anshun Feb 2025

Permanent Deformation Prediction Model Of Subgrade Soil Under Freeze-Thaw Cycles Based On Lstm And Transformer, Zhang Anshun

Journal of China & Foreign Highway

To accurately predict the permanent deformation of subgrade soil under the coupling effect of freeze-thaw cycles and traffic loads,a hybrid neural network model based on long short-term memory (LSTM ) and Transformer was proposed,building upon the results of dynamic triaxial tests.This model effectively captured the temporal dependencies and complex interactive effects among input variables,thereby significantly enhancing the accuracy and generalization ability of permanent deformation prediction of subgrade soil.The results indicate that higher confining pressure improves the resistance of subgrade soil to deformation,but its permanent deformation behavior is still significantly influenced by the magnitude of cyclic loading and the number of …

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Analysis Of Joint Load Transfer Performanc E Of Prefabricated Steel‑Concrete Hollow Pavement Slab, Zhu Guangshan, Dong Zihao, Yang Ye, Wang Jinshan Feb 2025

Analysis Of Joint Load Transfer Performanc E Of Prefabricated Steel‑Concrete Hollow Pavement Slab, Zhu Guangshan, Dong Zihao, Yang Ye, Wang Jinshan

Journal of China & Foreign Highway

In order to study the joint load transfer capacity of a prefabricated steel-concrete hollow pavement slab,a finite element model was established with ABAQUS to carry out numerical analysis.The variation laws of the maximum deflection value and joint load transfer coefficient of the pavement slab with and without cavitation were compared to analyze the load transfer capacity.The results show that when cavitation occurs in the slab,the load transfer coefficient of the slab decreases with the increase in the cavitation area,but the load transfer coefficient of the slab does not change significantly when the cavitation depth reaches a certain level.When there is …

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A Review Of Performance Of Cement- Stabilized Base Materials Containing Recycled Conc Rete Aggregate, Song Chengzhe, Li Jiaquan, Kong Jingxun, Zhou Changjun, An Xing Feb 2025

A Review Of Performance Of Cement- Stabilized Base Materials Containing Recycled Conc Rete Aggregate, Song Chengzhe, Li Jiaquan, Kong Jingxun, Zhou Changjun, An Xing

Journal of China & Foreign Highway

Semi-rigid base offers excellent performan ce and is widely used as a high-grade highway subgrade in China.Currently,with a large stockpile of waste concrete in the country,using it as aggregate in pavement base materials is of great significance for environmental protection,energy conservation,and emission reduction.In this paper,the basic performance indicators of recycled concrete aggregate (RCA ) and the performance of cement-stabilized base materials containing RCA,including strength,shrinkage,fatigue,and erosion resistance were reviewed.It finds that the basic performance indicators of RCA are lower than those of natural aggregate.Therefore,the proportion of RCA in base materials may be limited to 20% ‒ 50%.The shrinkage and erosion resistance …

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Research Progress Of Modified Asphalt With Graphene Materials, Zhang Zongwei, He Kai Feb 2025

Research Progress Of Modified Asphalt With Graphene Materials, Zhang Zongwei, He Kai

Journal of China & Foreign Highway

To clarify the research status of mo dified asphalt properties with graphene materials,relevant research literature in China and abroad was consulted to compare the effects of various graphene materials and preparation parameters on asphalt.The results show that graphene,nano graphite sheets,and oxidized graphene can improve the microstructure and road performance of asphalt,increase the service life of asphalt,and reduce the maintenance cost of asphalt.Continuously optimizing the preparation parameters of modified asphalt and exploring the mechanism of modified asphalt with new material not only help the promotion and application of new road asphalt technologies but also reduce energy consumption,pollutants,and carbon emissions,providing new ideas …

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Mechanical Performance Of Nuts In Tie Rod Assembly Of Anchorage System Of Suspension Bridge, Liu Zheng, Li Zhao, Qin Guifang, Xie Qinjian, Jiang Yuangen, Zhang Jiyong, Wang Lei, Ma Yafei Feb 2025

Mechanical Performance Of Nuts In Tie Rod Assembly Of Anchorage System Of Suspension Bridge, Liu Zheng, Li Zhao, Qin Guifang, Xie Qinjian, Jiang Yuangen, Zhang Jiyong, Wang Lei, Ma Yafei

Journal of China & Foreign Highway

In order to investigate the stress and fatigue performance of nuts in the tie rod assembly of the anchorage system of a long-span suspension bridge,the finite element software Ansys and Abaqus were used to establish the full bridge model and the local finite element models of the tie rod and the hexagonal nut,respectively.Secondly,the whole process variation law of the synergistic force of the tie rod and the nut under the axial tensile load was revealed.The difference in mechanical performance between slotted nuts and unslotted nuts was compared,and the detailed structural parameters of slotted nuts were optimized.Finally,the static tensile and fatigue …

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Installation Direction Design And Construction Control Of Sliding Bearing Of Continuous Girder Bridge, Guan Changlu, Sun Xiudong, Dong Hao, Wang Xingzhou Feb 2025

Installation Direction Design And Construction Control Of Sliding Bearing Of Continuous Girder Bridge, Guan Changlu, Sun Xiudong, Dong Hao, Wang Xingzhou

Journal of China & Foreign Highway

Continuous girder bridges can improve the structural stress,increase the structural bearing capacity,and promote ride comfort.However,some continuous girder bridges suffer from issues such as bearing dislocation,upper torsion,and damage to seismic arrestors.To identify deficiencies in current design and construction control,an in-depth analysis of these issues was conducted.The findings reveal the main reason is that the bidirectional sliding bearings (nearly half of the total ) fail to provide horizontal force,and the main sliding direction of the unidirectional sliding bearings is inconsistent with the deformation of the bridge superstructure.In this paper,factors including temperature-induced deformation,material shrinkage,elastic compression,creep,and construction process control of the bridge superstructure were …

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Crack Propagation Of Vehicle‑Steel Bridge Deck Slabs Based On Pavement Damage, Tang Sheng, Yin Xinfeng, Zhang Ming, Yan Wanli Feb 2025

Crack Propagation Of Vehicle‑Steel Bridge Deck Slabs Based On Pavement Damage, Tang Sheng, Yin Xinfeng, Zhang Ming, Yan Wanli

Journal of China & Foreign Highway

In order to study the influence of vehicles under different pavement damage conditions on crack propagation of welded toe at the roof of steel bridge deck slabs,finite element models of suspension bridges,fine vehicles,and local steel bridge deck slabs were established,and multiple groups of obstacle heights were set to simulate pavement damage.The explicit dynamic analysis program was used to simulate vehicle-bridge coupling vibration and extract the forces of vehicles on the steel bridge deck slabs at different lanes,speeds,and obstacle heights.The crack propagation life of the welded toe at the roof was obtained by applying them to a local steel bridge deck …

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Calculation Of Socket Depth For Circular Pipe Pier-Bearing Platform Socket Connection, Chen Jingli, Xiao Feng, Wang Zhigang, Wang Zhihai, Xu Yan Feb 2025

Calculation Of Socket Depth For Circular Pipe Pier-Bearing Platform Socket Connection, Chen Jingli, Xiao Feng, Wang Zhigang, Wang Zhihai, Xu Yan

Journal of China & Foreign Highway

The minimum socket depth for circular pipe pier-bearing platform socket connection can be calculated according to Article C.0.3 in the Specifications for Design of Highway Precast Concrete Bridges (JTG/T 3365 -05—2022 ).In order to enable engineering designers to fully understand and correctly apply the calculation formula in this article,this paper first introduced the main technical features of the typical connection scheme,as well as the structural failure principles and objectives formulated in the specification of the typical connection scheme.Then,it briefly introduced the experimental research content and results of the typical connection scheme and explained the key construction measures and their functions …

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Reliability Analysis Of Long‑Span Concrete Box Arch Bridge Under Temperature Effect Combinations, Zheng Junlin, Jiang Youbao, Zheng Xinhao, Lu Naiwei Feb 2025

Reliability Analysis Of Long‑Span Concrete Box Arch Bridge Under Temperature Effect Combinations, Zheng Junlin, Jiang Youbao, Zheng Xinhao, Lu Naiwei

Journal of China & Foreign Highway

The existing design methods for concrete arch bridge structures do not consider the random characteristics of the eccentricity generated by load effects and overlook the influence of stochastic eccentricity on structural reliability.To address this deficiency,a calculation model for eccentricity under temperature effect combinations was derived.The random characteristics of eccentricity for different sections of the main arch of concrete arch bridges and their sectional bearing capacities were analyzed under different load parameter combinations.By utilizing the Monte Carlo method,reliability indices were computed for different sections of the main arch and different load parameter combinations after considering the random characteristics of eccentricity.The results …

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Preparation And Performance Of Emulsified Asphalt With High-Temperature Resistant And Wheel Sticking-Free Effects, Yan Han, Zha Xudong, Kang Xiaogang, Gong Yan, Zhang Zhengji, Zhang Wenshuai Feb 2025

Preparation And Performance Of Emulsified Asphalt With High-Temperature Resistant And Wheel Sticking-Free Effects, Yan Han, Zha Xudong, Kang Xiaogang, Gong Yan, Zhang Zhengji, Zhang Wenshuai

Journal of China & Foreign Highway

To address the problem of wheel sticking at high temperatures in the construction process of existing wheel sticking-free emulsified asphalt of tack coat,this paper adopted the composite modification method of 70# and 15# matrix asphalt and waterborne polyurethane resin (WPR ) to prepare hard asphalt-WPR (HA-WPR )-modified emulsified asphalt in accordance with the high-temperature resistant and wheel sticking-free requirements.Through a series of laboratory tests,the technical performance,wheel sticking-free performance,and interlayer bonding performance of the emulsified asphalt were researched and compared with ordinary wheel sticking-free emulsified asphalt and ordinary emulsified asphalt tack coat oil.The results show that the technical performance of the …

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Model Analysis Of Axial Compressive Mechanical Properties Of Concrete Column Constrained By Textile-Reinforced Engineered Cementitious Composites, Ma Gao, Wang Zhaoyang Feb 2025

Model Analysis Of Axial Compressive Mechanical Properties Of Concrete Column Constrained By Textile-Reinforced Engineered Cementitious Composites, Ma Gao, Wang Zhaoyang

Journal of China & Foreign Highway

In order to avoid the problem of matrix cracking in textile-reinforced concrete (TRC ),a reinforcement method of textile-reinforced engineered cementitious composites (ECC ),namely TRECC composed of textile and high-performance ECC was proposed.However,the research on the axial compressive mechanical properties of TRECC-constrained concrete in China and abroad is still insufficient,and there is a lack of reliable strength and ultimate strain analysis models.A total of 116 axial compression test results of TRC-constrained concrete columns and 125 axial compression test results of TRECC-constrained concrete columns were collected.The confinement mechanisms and failure modes of TRECC and TRC-constrained concrete were compared.Then,the strength models and ultimate …

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Key Techniques For Constructing Flexible Geosynthetic Reinforced Soil Abutments, Yu Xiaoxiao, Xu Chao, Li Haoyu, Zuo Binli Feb 2025

Key Techniques For Constructing Flexible Geosynthetic Reinforced Soil Abutments, Yu Xiaoxiao, Xu Chao, Li Haoyu, Zuo Binli

Journal of China & Foreign Highway

The flexible geosynthetic reinforced soil (GRS ) abutments offer several advantages,including cost saving,reduced bridgehead misalignment,and good seismic performance,showing great potential for application in transportation engineering both in China and abroad.The flexible GRS abutment is essentially composed of a composite structure formed by closely spaced layers of geosynthetic reinforcement material,and the construction quality and load-bearing capacity are crucial to the success of the project.To ensure construction quality and study the construction process of flexible GRS abutments,a construction site monitoring method was adopted.Based on the experience from the construction of a vehicular overpass on the Wuwei ‒ Yuexi Expressway,the quality control measures …

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Research On Mechanical Entry Excavation And Reinforcement Measures For Large Cross-Section Tunnel, Liang Xiao, Li Ke, Guo Hongyan, Hu Xuebing, Yao Chengrui Feb 2025

Research On Mechanical Entry Excavation And Reinforcement Measures For Large Cross-Section Tunnel, Liang Xiao, Li Ke, Guo Hongyan, Hu Xuebing, Yao Chengrui

Journal of China & Foreign Highway

With the innovation of tunnel construction techniques and mechanical equipment,mechanical drilling and blasting for mountain tunnels have gradually developed.However,several challenges exist during the mechanical entry excavation for mountain tunnels,including the significant influence of geological factors,limited equipment adaptability,and constrained working space.This research,based on a specific tunnel project,utilized FLAC3D finite difference software to study the mechanical excavation method and auxiliary reinforcement measures for shallow-buried segments at the large cross-section tunnel portal.A comparative analysis was conducted on the displacement of surrounding rock,the stress of supporting structures,and the variation of plastic zones before and after tunnel face reinforcement for different advances per cycle and …

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Application Research Of Bim Technology In Highway Prefabricated Bridge Scheme Design, Li Jinlong, Wang Xinnan, Liu Dongsheng, Chen Zhongzhi Feb 2025

Application Research Of Bim Technology In Highway Prefabricated Bridge Scheme Design, Li Jinlong, Wang Xinnan, Liu Dongsheng, Chen Zhongzhi

Journal of China & Foreign Highway

At present,the highway bridge scheme requires continuous adjustments and upgrading due to iterative updates of design data and refined investigation of the surrounding environment of the bridge site.This paper upgraded the traditional route design software,developed a GIS-integrated platform,built a three-dimensional environment with design data as the core,and created a bridge scheme model through parametric intelligent design.It also evaluated and optimized the bridge scheme based on the integration of the bridge model and the surrounding environment.The results show that by using BIM technology,the forward design of a bridge scheme based on a three-dimensional environment is realized.This approach automates the scale statistics …

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Determining The Limitations Of Class F Fly Ash Compared To Class G Cement In Hydrocarbon Wells Application, Youssef Helmy Feb 2025

Determining The Limitations Of Class F Fly Ash Compared To Class G Cement In Hydrocarbon Wells Application, Youssef Helmy

Theses and Dissertations

Cement is a material commonly used in multiple applications in different industries. Among the industries that uses cement is the oil and gas industry. API (American Petroleum Institute) Class G cement that is the most incorporated form of cement used in the cementation of oil and gas wells to provide several forms of protection and stabilization for the casings. However, Class G cement is contested in terms of efficiency, costs, and environmental awareness against Class F fly ash geopolymers by researchers. This research aims to explore the potential limitations that fly ash geopolymer might have for its use in the …

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Partial Replacement Of Ordinary Portland Cement In Concrete By Limestone Calcined Clay (Lc2), Merna Abdelaziz Feb 2025

Partial Replacement Of Ordinary Portland Cement In Concrete By Limestone Calcined Clay (Lc2), Merna Abdelaziz

Theses and Dissertations

Limestone calcined clay (LC2) technique is a new approach that could address the environmental problem corelated with the construction industry due to its vital reliance on the ordinary Portland cement in its various applications. LC2 technique involves partial replacement of the OPC in concrete by limestone and calcined kaolinite clay with a ratio of 1:2 respectively. The main advantage of this technique is its high applicability due to its direct application on site. This study investigated the applicability of incorporating the LC2 technique in the construction industry. Three replacement percentages of OPC by LC2 in concrete were explored, which are …

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Viscoelastic Protective Armor Liners And Protective Armor, Fatih Dogan, Cody Thomas, Catherine Johnson Feb 2025

Viscoelastic Protective Armor Liners And Protective Armor, Fatih Dogan, Cody Thomas, Catherine Johnson

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Microstructural, Oxidation, And Mechanical Behavior Of Nbti-Based Refractory Alloys With 5 To 10 Pct Co, Cr, And Ni Additions, Tae Kyong John Kim, Jennifer Carter Feb 2025

Microstructural, Oxidation, And Mechanical Behavior Of Nbti-Based Refractory Alloys With 5 To 10 Pct Co, Cr, And Ni Additions, Tae Kyong John Kim, Jennifer Carter

Faculty Scholarship

NbTi-based refractory alloys with additions of Co, Cr, and Ni represent an interesting medium-entropy alloy system with potential for protective oxide film formation, high strength, and ductility. This study investigates the microstructural evolution, oxidation behavior, and mechanical properties of NbTi-based alloys containing 5 to 10 at. pct Co, Cr, and Ni. CALPHAD predictions suggest that this composition range can be heat treated to obtain a predominantly body-centered cubic matrix phase. Mechanical properties, including microhardness, yield strength, maximum strength, and specific strength are evaluated through isothermal compression tests conducted between room temperature and 800 °C. The oxidation kinetics of these alloys …

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Research Of Horse Oil Based Shampoo For Fine Hair Involving Local Oils And Enzyms Transesterification, Sherzod Y. Rakhmanov, Madina O. Khaydarova, Bonu G. Аrislonboyeva, Nilufar A. Khaydarova, Dilshod P. Rakhimov Feb 2025

Research Of Horse Oil Based Shampoo For Fine Hair Involving Local Oils And Enzyms Transesterification, Sherzod Y. Rakhmanov, Madina O. Khaydarova, Bonu G. Аrislonboyeva, Nilufar A. Khaydarova, Dilshod P. Rakhimov

CHEMISTRY AND CHEMICAL ENGINEERING

Currently, there are many shampoos, balms and various hair masks. Shampoo-tonics have also been introduced into production, providing temporary coloring without damaging the hair structure. In this research work, we set ourselves the task of conducting a study of a shampoo for soft hair that provides durability, granularity and shine to hair by transesterifying horse oil with the enzyme lipase and the surfactant sodium lauryl sulfate. Depending on the type of shampoo, we conducted a scientific study using the following experimental method. To add horse oil to the shampoo formula, we re-esterified mixtures of horse oil and sunflower oil in …

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Effect Of Desorption On Photocatalytic Decomposition Of Methylene Blue Using Materials From Solid Wastes Of Production Of Molybdenum Oxides (Vi) And Titanium Dioxide, Dilshoda R. Tursunova, Shahlo Sh. Daminova, Rafael A. Nusretov, Ayipbergen Shiknazarov, Zuhra Ch. Kadirova Feb 2025

Effect Of Desorption On Photocatalytic Decomposition Of Methylene Blue Using Materials From Solid Wastes Of Production Of Molybdenum Oxides (Vi) And Titanium Dioxide, Dilshoda R. Tursunova, Shahlo Sh. Daminova, Rafael A. Nusretov, Ayipbergen Shiknazarov, Zuhra Ch. Kadirova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work is to obtain and characterize a composite photocatalyst based on the spent catalyst of the Shurtan Mining and Chemical Combine based on titanium dioxide and molybdenum-containing waste of the Almalyk Mining and Metallurgical Combine and to identify factors influencing the process of photocatalytic decomposition of methylene blue in solution under the action of UV light. In this work, we studied the kinetics of photocatalytic decomposition of methylene blue on the surface of materials obtained from technogenic solid waste, which were thermally activated at a temperature of 600 ° C. It was found that desorption plays …

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X-Ray Photoelectron Spectroscopy Investigation Of Surface Changes In Chalcocite And Enargite Minerals Following Oxidation Treatment, Berdakh T. Daniyarov, Miki Hajime, Baxtigul Y. Ruzieva, Shahlo Sh. Daminova Feb 2025

X-Ray Photoelectron Spectroscopy Investigation Of Surface Changes In Chalcocite And Enargite Minerals Following Oxidation Treatment, Berdakh T. Daniyarov, Miki Hajime, Baxtigul Y. Ruzieva, Shahlo Sh. Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

Copper sulfide minerals, such as chalcocite (Cu₂S) and enargite (Cu₃AsS₄), are important sources of copper, which has wide applications in electronics, energy, and other industries. These minerals are traditionally processed using flotation methods, which are one of the most effective ways to extract copper from sulfide ores. However, the success of flotation of copper sulfides, such as chalcocite and enargite, strongly depends on changes in their surface properties, such as hydrophobicity or hydrophilicity, which can be modified by various chemical reagents. To further understand the impact of these chemical reagents on chalcocite and enargite minerals, X-ray photoelectron spectroscopy (XPS) was …

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Synthesis And Study Of Complex Compounds With 1,3,4-Oxadiazole Derivatives Based On Ammonium Vanadate, Mehribon A. Pirimova, Shaxnoza A. Kadirova, Abduhakim A. Ziyayev Feb 2025

Synthesis And Study Of Complex Compounds With 1,3,4-Oxadiazole Derivatives Based On Ammonium Vanadate, Mehribon A. Pirimova, Shaxnoza A. Kadirova, Abduhakim A. Ziyayev

CHEMISTRY AND CHEMICAL ENGINEERING

This research work examines the synthesis, structure and properties of ammonium vanadate complex compounds based on 1,3,4-oxadiazole derivatives. Competing donor centers in coordination, electronic and geometric structures of the ligand molecule were studied based on quantum chemical calculations using the Gaussian09 LanL2DZ software package. Among the ligands, 2-carboxymethylthio-5-phenyl-1,3,4-oxadiazole ligand has been shown to have more competitive donor atoms than other ligands.

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Structural Features And Morphology Of Biodegradable Composites Based On Polylactide And Corn Starch, Eygeniy N. Poddenezhny, Andrei A. Boiko, Ekaterina E. Trusova, Viktor M. Shapovalov Feb 2025

Structural Features And Morphology Of Biodegradable Composites Based On Polylactide And Corn Starch, Eygeniy N. Poddenezhny, Andrei A. Boiko, Ekaterina E. Trusova, Viktor M. Shapovalov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work was to study the morphology and structural features of biodegradable composites based on polylactide, filled with corn starch formed by extrusion method. The characteristics of the obtained materials were investigated by scanning electron microscopy, X-ray diffraction, IR spectroscopy. It was established that the presence of polyethylene glycol PEG–4000 as a plasticizer and surfactant – glycerin monostearate in the initial mixture leads to the formation of a nonporous heterogeneous system, in which starch particles are statistically distributed in the matrix. The starch concentration in the composite varied from 20 to 55 wt. %. When the starch …

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Influence Of Thermal Cycling On The Resistance Of Bismuth Cuprates Synthesized Using Solar Energy, Dilbara Dj. Gulamova, Sirojiddin Z. Mirzaev, Sirojiddin Kh. Bobokulov, Elyor B. Eshonkulov, Grigor I. Mamniashvili Feb 2025

Influence Of Thermal Cycling On The Resistance Of Bismuth Cuprates Synthesized Using Solar Energy, Dilbara Dj. Gulamova, Sirojiddin Z. Mirzaev, Sirojiddin Kh. Bobokulov, Elyor B. Eshonkulov, Grigor I. Mamniashvili

CHEMISTRY AND CHEMICAL ENGINEERING

A bulk superconducting ceramic synthesized using solar technology exhibits a sharp increase in resistance from zero to approximately 160Ω at 250 K. Four thermal cycling tests in the range of 79-360 K revealed a tendency for the temperature transition interval to narrow and a comparatively sharp jump at 290 K, suggesting a superconducting transition. The effect of stress concentration at grain boundaries during four cycles leads to an increase in the superconducting transition temperature due to the cumulative rise in stress and pinning force. The assumption that these effects are caused by superconducting homologous phases is based on the manifestation …

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The Effect Of B2o3 On The Structure And Properties Of The Glasses Of The Na2o–Cao–Mgo–Sio2–P2o5 System, Mihail V. Dyadenko, Ivan A. Levitskiy, Irina I. Kurilo, Alexander S. Glinskii Feb 2025

The Effect Of B2o3 On The Structure And Properties Of The Glasses Of The Na2o–Cao–Mgo–Sio2–P2o5 System, Mihail V. Dyadenko, Ivan A. Levitskiy, Irina I. Kurilo, Alexander S. Glinskii

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this work was to study the effect of boron oxide on the physico-chemical and technological properties of glasses of the Na2O–CaO–MgO–SiO2–P2O5 system. The study of crystallization ability, density, the temperature of the onset of softening, as well as the chemical stability of experimental glasses modified with boron oxide, made it possible to indirectly assess their ability to dissolve in aqueous solutions and show bioactive properties. The article presents the results of the influence of B2O3 on the viscosity of the studied glasses and the value of their …

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