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Articles 5461 - 5490 of 16712

Full-Text Articles in Engineering

Anisotropic Cuinse2 Nanocrystals: Synthesis, Optical Properties And Their Effect On Photoelectric Response Of Dye-Sensitized Solar Cell, Ahmed Mysara, M Mohsen Abdelaziz, A N. Emam, A S. Mansour, A A. F. Zikry, M .B Mohamed, Y H. Elbashar Nov 2020

Anisotropic Cuinse2 Nanocrystals: Synthesis, Optical Properties And Their Effect On Photoelectric Response Of Dye-Sensitized Solar Cell, Ahmed Mysara, M Mohsen Abdelaziz, A N. Emam, A S. Mansour, A A. F. Zikry, M .B Mohamed, Y H. Elbashar

Nanotechnology Research Centre

CuInSe2 I-III-VI2 ternary is a semiconductor considered very good efficient solar energy conversion material. An organometallic pyrolysis method is used to prepare monodisperse CuInSe2 nanoparticles using a mixture of oleylamine, and trioctylphosphine, as capping materials. The particle shape changes to dot, rods or flowers occur via varying the reaction temperatures (160, 200, 220±C) respectively. The obtained particles have been characterized to determine the shape and size of CuInSe2 nanoparticles using HR-TEM and XRD. The optical and electronic properties of these particles have been investigated and discussed in detail. Then the different shapes of CuInSe …

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Basis Set Truncation Further Clarifies Vibrational Coherence Spectra, Daniel B. Turner, Paul C. Arpin Nov 2020

Basis Set Truncation Further Clarifies Vibrational Coherence Spectra, Daniel B. Turner, Paul C. Arpin

Materials Science and Engineering Faculty Publications and Presentations

Coherent vibrational oscillations in femtosecond transient-absorption spectra have been interpreted since the 1990s using a model based on Gaussian wavepacket dynamics. The oscillations are often studied using probe-wavelength dependent plots of the oscillation amplitude and phase that are known as vibrational coherence spectra. Here we show that restricting the basis of the wavepacket to a small number of eigenstates clarifies several features in vibrational coherence spectra. Improving the understanding of vibrational coherence signatures will help distinguish them from signatures of electronic coherence that arise from measurements of strongly coupled excitonic states in molecular aggregates and light-harvesting proteins.

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High-Performance Flexible Bismuth Telluride Thin Film From Solution Processed Colloidal Nanoplates, Madhusudan Kongara, Tony Varghese, Karthik Chinnathambi, Jesse Schimpf, Josh Eixenberger, Paul H. Davis, Yaqiao Wu, David Estrada Nov 2020

High-Performance Flexible Bismuth Telluride Thin Film From Solution Processed Colloidal Nanoplates, Madhusudan Kongara, Tony Varghese, Karthik Chinnathambi, Jesse Schimpf, Josh Eixenberger, Paul H. Davis, Yaqiao Wu, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

Thermoelectric generators are an environmentally friendly and reliable solid‐state energy conversion technology. Flexible and low‐cost thermoelectric generators are especially suited to power flexible electronics and sensors using body heat or other ambient heat sources. Bismuth telluride (Bi2Te3) based thermoelectric materials exhibit their best performance near room temperature making them an ideal candidate to power wearable electronics and sensors using body heat. In this report, Bi2Te3 thin films are deposited on a flexible polyimide substrate using low‐cost and scalable manufacturing methods. The synthesized Bi2Te3 nanocrystals have a thickness of 35 ± …

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Facile Synthesis Of Nitrogen-Doped Graphene-Like Active Carbon Materials For High Performance Lithium-Sulfur Battery, Quan-Hua Meng, Wen-Wen Deng, Chang-Ming Li Oct 2020

Facile Synthesis Of Nitrogen-Doped Graphene-Like Active Carbon Materials For High Performance Lithium-Sulfur Battery, Quan-Hua Meng, Wen-Wen Deng, Chang-Ming Li

Journal of Electrochemistry

Lithium-sulphur (Li-S) battery is regarded as a promising energy storage device because of its high theoretical capacity. However, the low S utilization and short cycling life limit the commercial applications. In this work, nitrogen-doped graphene-like carbon (NGC) materials were synthesized by simply pyrolyzing and carbonizing the mixture of melamine (C3H6N6) and L-cysteine (C3H7NO2S). The graphene-like structure in NGC effectively buffered the volume change of S during the discharge/charge process and improved the cycling stability. Meanwhile, nitrogen-containing functional groups in NGC facilitated the transportation of ions and suppressed the …

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Electrochemical Engineering Of Carbon Nanodots, Lei Bao, Dai-Wen Pang Oct 2020

Electrochemical Engineering Of Carbon Nanodots, Lei Bao, Dai-Wen Pang

Journal of Electrochemistry

Aqueous batteries have been considered to be a competitive candidate for large-scale energy storage. However, most of aqueous batteries adopt inorganic electrode materials with metallic elements, which are based on the reversible insertion of metal ions, making their application being highly hindered by limited cycle life, environmental issue, high cost and low reserves. On the other hand, organic electrode materials offer the advantages of abundant reserves, tunable structures, renewability and environmental benignity. Furthermore, the wide internal space enables these organics to flexibly store various charge carriers. Organics have been investigated as the alternative to inorganic electrode materials. Herein, we review …

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Porous-Electrode Theory Of Lithium Ion Battery: Old Paradigm And New Challenge, Xiao-Xiao Wang, Zi-Rui Zhou, Qiang Shan, Zeng-Ming Zhang, Jun Huang, Yu-Wen Liu, Sheng-Li Chen Oct 2020

Porous-Electrode Theory Of Lithium Ion Battery: Old Paradigm And New Challenge, Xiao-Xiao Wang, Zi-Rui Zhou, Qiang Shan, Zeng-Ming Zhang, Jun Huang, Yu-Wen Liu, Sheng-Li Chen

Journal of Electrochemistry

A critical review on the porous electrode theory developed by Newman and his colleagues is presented. We propose several ideas for further development of this theory by analyzing its limitations. The classical Newman theory does not consider ion steric effect in describing ion transport in electrolyte solutions, which can be amended by a newly developed ion-vacancy coupled charge transfer model for ion transport in concentrated solutions. Ion transport in solid particles of active materials is essentially an ion-electron coupled transport process, and its rationality is verified by comparing the calculated and experimental diffusion coefficients of Li + ion in intercalation …

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Progress And Prospects On Multifunctional Coating Separators For Lithium-Sulfur Battery, Zhuang-Zhuang Wei, Nan-Xiang Zhang, Feng Wu, Ren-Jie Chen Oct 2020

Progress And Prospects On Multifunctional Coating Separators For Lithium-Sulfur Battery, Zhuang-Zhuang Wei, Nan-Xiang Zhang, Feng Wu, Ren-Jie Chen

Journal of Electrochemistry

The development of advanced energy storage systems is crucial to meet the growing demand for electric vehicles, portable devices and renewable energy storage. Lithium-sulfur (Li-S) batteries, with their advantages of high specific energy, low cost of raw materials and environmental friendliness, are hotspots in the research field of new high performance batteries. However, there are still many problems which hinder the practical applications of lithium-sulfur batteries, such as the shuttle effect of soluble polysulfide intermediates, the growth of lithium dendrites, and the thermal stability and safety of lithium-sulfur batteries during use. The design of multifunctional coating separator is one of …

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Licoo2 As Sulfur Host To Enhance Cathode Volumetric Capacity For Lithium-Sulfur Battery, Lu Wang, Xue-Ping Gao Oct 2020

Licoo2 As Sulfur Host To Enhance Cathode Volumetric Capacity For Lithium-Sulfur Battery, Lu Wang, Xue-Ping Gao

Journal of Electrochemistry

Lithium-sulfur battery is one of the most promising secondary battery systems due to its super high theoretical gravimetric and volumetric energy densities (2600 Wh·kg-1 and 2800 Wh·L-1, respectively). However, the practical volumetric capacity of sulfur cathode is still unsatisfied due to the overuse of low-density host materials, such as carbon nanomaterials. Herein, commercial LiCoO2 with the high tap density of 2.94 g·cm-3 was used as the host material to build high density sulfur-based composite and compact electrode for increasing the volumetric capacity. Obviously, the tap density of the as-prepared S/LiCoO2 composite was 1.90 g·cm …

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Research Progress Of Key Components In Lithium-Sulfur Batteries, Jia-Jia Chen, Quan-Feng Dong Oct 2020

Research Progress Of Key Components In Lithium-Sulfur Batteries, Jia-Jia Chen, Quan-Feng Dong

Journal of Electrochemistry

Due to the much higher theoretical specific capacity and energy density than the ones of traditional lithium ion battery, Li-S batteries have long been at the pinnacle in the realms of high-energy Li-metal batteries. However, the complicated electrochemical reactions on the sulfur cathode and Li anode, induced by the thermodynamic and kinetic behaviors of lithium polysulfides, are the intrinsic bottleneck to realize the full potential of Li-S batteries for practical application. In this review, we firstly discuss the roles, and thermodynamic and kinetic behaviors of polysulfides in the charging and discharging processes of Li-S batteries. Then, the functional design and …

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A Model For The Anodic Carbonization Of Alkaline Polymer Electrolyte Fuel Cells, Qi-Hao Li, Ying-Ming Wang, Hua-Long Ma, Li Xiao, Gong-Wei Wang, Jun-Tao Lu, Lin Zhuang Oct 2020

A Model For The Anodic Carbonization Of Alkaline Polymer Electrolyte Fuel Cells, Qi-Hao Li, Ying-Ming Wang, Hua-Long Ma, Li Xiao, Gong-Wei Wang, Jun-Tao Lu, Lin Zhuang

Journal of Electrochemistry

The alkaline polymer electrolyte fuel cell (APEFC) has made appreciable progress in recent years but is still suffering performance loss during discharge with air as the oxidant. Several theories have been suggested to interpret the loss. However, efforts are still needed to reach a clear quantitative understanding. Based on the major experimental findings in combination with thermodynamics and kinetics of the reactions involved in the anode, this paper presents a model featuring layered carbonization in the anode and relevant grouped equations. The simulation results generated from the latter are compared with experiments, and possible principles to suppress the performance loss …

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Research Progress Of Sulfur Cathode Catalytic Conversions For Lithium-Sulfur Batteries, Qin-Jun Shao, Jian Chen Oct 2020

Research Progress Of Sulfur Cathode Catalytic Conversions For Lithium-Sulfur Batteries, Qin-Jun Shao, Jian Chen

Journal of Electrochemistry

The electrochemical reduction of sulfur (S) takes place through multistep reactions when S is used as a cathode material. The complete discharge of S to form final product lithium sulfide (Li2S) is a two-electron reaction. The formation of low-order lithium polysulfides (LiPS) needs to overcome certain energy barriers. And the reduction of Li2S2 to Li2S is the rate-limited step. The reaction kinetic of sulfur cathode is the critical key to determine the electrochemical performance of Li-S batteries, such as specific energy, specific power and low temperature performance, etc. Accelerating the rate-limited step kinetics …

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Liquid Metal Electrodes For Electrochemical Energy Storage Technologies, Hao-Miao Li, Hao Zhou, Kang-Li Wang, Kai Jiang Oct 2020

Liquid Metal Electrodes For Electrochemical Energy Storage Technologies, Hao-Miao Li, Hao Zhou, Kang-Li Wang, Kai Jiang

Journal of Electrochemistry

Electrochemical energy storage technologies (ESTs) with low cost, long lifespan and high safety are of great importance for efficient integration of renewable energy into the grid. Liquid metal electrodes (LMEs) possessing the merits of high electronic conductivity, easy manufacture and amorphous structure is of great application value in the field of energy storage batteries. During charge-discharge processing, the LMEs could avoid the issues of structural deformation and dendrite growth in solid metal electrodes, which could effectively extend the cycle life of the LME based batteries. Moreover, LME based batteries are easy to be scaled up and less expensive, which are …

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Porous Electrodes In Electrochemical Energy Storage Systems, Wei-Xiao Ji, Gong-Wei Wang, Qiang Wang, Li-Jun Bai, De-Yang Qu Oct 2020

Porous Electrodes In Electrochemical Energy Storage Systems, Wei-Xiao Ji, Gong-Wei Wang, Qiang Wang, Li-Jun Bai, De-Yang Qu

Journal of Electrochemistry

Professor C.S. Cha was among the pioneers who have introduced modern electrochemistry to China. Under his leadership, the electrochemical research group in Wuhan University became one of the global powerhouses in fundamental and applied electrochemical researches. During the past many decades, Professor Cha and his colleagues in the university have educated and trained many students who have become part of the backbone of electrochemistry worldwide. In this review, we demonstrate the solid foundation laid by Professor Cha and his colleagues in Wuhan University, and the advancements made in the area of porous electrodes by the authors. All the authors in …

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Highly Efficient Co2 Utilization Via Molten Salt Co2 Capture And Electrochemical Transformation Technology, Bo-Wen Deng, Hua-Yi Yin, Di-Hua Wang Oct 2020

Highly Efficient Co2 Utilization Via Molten Salt Co2 Capture And Electrochemical Transformation Technology, Bo-Wen Deng, Hua-Yi Yin, Di-Hua Wang

Journal of Electrochemistry

The molten electrolytes exhibit high CO2 absorption capacities, wide electrochemical windows and excellent reaction kinetics, which are promising electrolyte candidates for efficient capture and electrochemical conversion of high-flux CO2 driven by renewable and clean electricity sources. This short review introduces the recent advancements of CO2 electroreduction achieved by the authors using molten salt CO2 capture and electrochemical transformation (MSCC-ET) technology, involving CO2 absorption kinetics, cathodic kinetics, controllable synthesis of carbon products with unique nanostructures, development of inert oxygen evolution anodes and CO2 conversion efficiency as well as energy efficiency. The challenges and prospects are …

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Temporally Multiplexed Ladar Polarimeter, Christian Keyser, Richard Kenneth Martin Oct 2020

Temporally Multiplexed Ladar Polarimeter, Christian Keyser, Richard Kenneth Martin

AFIT Patents

In a polarimeter, a polarization modulator changes a polarization phase of an output optical pulse with a modulation function that varies in time over the duration of the optical pulse. A static polarization state analyzer, which includes a one or more static polarization component analyzers and detectors, receives the modulated optical pulse after interaction with a target medium and provides time varying intensities of the polarization components of the received pulse. A signal processing module determines a polarization property of the target medium, such as a Mueller matrix, dependent upon time varied intensities over the duration of the received optical …

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In Vitro Study Of Biodegradation Of Glass And Glass Crystals Of The R2o-Ro-Caf2-P2o5-Al2o3-Sio2 System, Aripova Mastura, Mkrtchyan Ripsime Oct 2020

In Vitro Study Of Biodegradation Of Glass And Glass Crystals Of The R2o-Ro-Caf2-P2o5-Al2o3-Sio2 System, Aripova Mastura, Mkrtchyan Ripsime

CHEMISTRY AND CHEMICAL ENGINEERING

For bioactive glasses and glass crystals, biodegradation is the most important parameter. The biodegradation process was studied for glasses and glass crystals synthesized in the R2O-RO-CaF2-P2O5-Al2O3-SiO2 system. Degradation analysis of samples was carried out on a Hitachi 902 biochemical analyzer in 0.9% NaCl, 3.8% sodium citrate solution and human serum. . The kinetics of leaching in various environments, the influence of the components of glasses and glass crystals on their biodegradation have been determined. The composition of glass that is most susceptible to degradation has been determined. IR spectroscopic analysis of glasses and crystallized glasses in vitro showed that all …

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Configuration And Competitive Reactivity Of Ligands In Mixed Ligand Complexes Of Dialkylditiophosphates And Aminobenbenzimidazole (Part 2. Zn, Fe, Ni), Esbergenova Botakoz, Daminova Shakhlo, Kadirova Zuhra, Sharipov Khasan Oct 2020

Configuration And Competitive Reactivity Of Ligands In Mixed Ligand Complexes Of Dialkylditiophosphates And Aminobenbenzimidazole (Part 2. Zn, Fe, Ni), Esbergenova Botakoz, Daminova Shakhlo, Kadirova Zuhra, Sharipov Khasan

CHEMISTRY AND CHEMICAL ENGINEERING

With the aim of determination of electronic and geometrical structures of mixed-ligand complexes, theoretical modeling of the structures of coordination compounds of transition metals with dialkyldithiophosphate chelating ligands with aminobenzimidazoles carried out using quantum chemical methods. Using BIOVIA Materials Accelrys Studio 2017 software packages, the geometry, electron density distribution, and frontier orbitals calculated for the mixed ligand complexes Zn(II), Cu(II), Ni(II), Fe(III), which is necessary for understanding the electronic structure of coordination compounds with chelating ligands.

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Fully Inkjet-Printed Multilayered Graphene-Based Flexible Electrodes For Repeatable Electrochemical Response, Twinkle Pandhi, Kiyo Fujimoto, Pete Barnes, Jasmine Cox, Hui Xiong, Paul H. Davis, Harish Subbaraman, David Estrada Oct 2020

Fully Inkjet-Printed Multilayered Graphene-Based Flexible Electrodes For Repeatable Electrochemical Response, Twinkle Pandhi, Kiyo Fujimoto, Pete Barnes, Jasmine Cox, Hui Xiong, Paul H. Davis, Harish Subbaraman, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

Graphene has proven to be useful in biosensing applications. However, one of the main hurdles with printed graphene-based electrodes is achieving repeatable electrochemical performance from one printed electrode to another. We have developed a consistent fabrication process to control the sheet resistance of inkjet-printed graphene electrodes, thereby accomplishing repeatable electrochemical performance. Herein, we investigated the electrochemical properties of multilayered graphene (MLG) electrodes fully inkjet-printed (IJP) on flexible Kapton substrates. The electrodes were fabricated by inkjet printing three materials – (1) a conductive silver ink for electrical contact, (2) an insulating dielectric ink, and (3) MLG ink as the sensing material. …

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Far Infrared Radiation Property Of Elbaite/Alumina Composite Materials, Qi Lu, Bowen Li, Huan Zhang Oct 2020

Far Infrared Radiation Property Of Elbaite/Alumina Composite Materials, Qi Lu, Bowen Li, Huan Zhang

Michigan Tech Publications, Part 1

Far infrared materials have been prepared by precipitation method using natural elbaite powder as raw materials, which belongs to tourmaline group. The chemical formula of elbaite is Na(Al, Li)3Al6B3Si6O27(O, OH, F)4. X-ray powder diffraction (XRD) shows that elbaite and alumina in composite material has good crystal form. In addition, XRD results indicate the formation of alumina crystallites show that alumina powder exists as nano-meter particles on the surface of elbaite powder. It can be calculated the particles diameter of Al2O3 is 47.86nm. The maximum infrared radiation rate of tourmaline/alumina composite materials is 0.89 when the ratio of alumina in elbaite …

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Comparative Study Of Silk-Based Magnetic Materials: Effect Of Magnetic Particle Types On The Protein Structure And Biomaterial Properties, Ye Xue, Samuel Lofland, Xiao Hu Oct 2020

Comparative Study Of Silk-Based Magnetic Materials: Effect Of Magnetic Particle Types On The Protein Structure And Biomaterial Properties, Ye Xue, Samuel Lofland, Xiao Hu

College of Science & Mathematics Departmental Research

This study investigates combining the good biocompatibility and flexibility of silk protein with three types of widely used magnetic nanoparticles to comparatively explore their structures, properties and potential applications in the sustainability and biomaterial fields. The secondary structure of silk protein was quantitatively studied by infrared spectroscopy. It was found that magnetite (Fe3O4) and barium hexaferrite (BaFe12O19) can prohibit β-sheet crystal due to strong coordination bonding between Fe3+ ions and carboxylate ions on silk fibroin chains where cobalt particles showed minimal effect. This was confirmed by thermal analysis, where a high temperature degradation peak was found above 640 °C in …

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Mechanochemical Conversion Kinetics Of Red To Black Phosphorus And Scaling Parameters For High Volume Synthesis, Samuel V. Pedersen, Florent Muramutsa, Joshua D. Wood, Chad Husko, David Estrada, Brian J. Jaques Oct 2020

Mechanochemical Conversion Kinetics Of Red To Black Phosphorus And Scaling Parameters For High Volume Synthesis, Samuel V. Pedersen, Florent Muramutsa, Joshua D. Wood, Chad Husko, David Estrada, Brian J. Jaques

Materials Science and Engineering Faculty Publications and Presentations

Adopting black phosphorus (BP) as a material in electronic and optoelectronic device manufacturing requires the development and understanding of a large-scale synthesis technique. To that end, high-energy planetary ball milling is demonstrated as a scalable synthesis route, and the mechanisms and conversion kinetics of the BP phase transformation are investigated. During the milling process, media collisions rapidly compress amorphous red phosphorus (RP) into crystalline, orthorhombic BP flakes, resulting in a conversion yield of ≈90% for ≈5 g of bulk BP powder. Milling conversion kinetics, monitored via ex situ x-ray diffraction, manifest a sigmoidal behavior best described by the Avrami rate …

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Research Of The Process Of Deformation Of Extractional Phosphoric Acid From Phosphorites Of Central Kyzylkum, Khodjamkulov Sakhomiddin, Mirzakulov Kholtura, Melikulova Gavkhar, Usmanov Ilkham Oct 2020

Research Of The Process Of Deformation Of Extractional Phosphoric Acid From Phosphorites Of Central Kyzylkum, Khodjamkulov Sakhomiddin, Mirzakulov Kholtura, Melikulova Gavkhar, Usmanov Ilkham

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this research was to determine the optimal technological parameters for the purification of extraction phosphoric acid based on phosphorites of Central Kyzylkum from fluorine by precipitation with sodium salts. The influence of the norm of sodium silicate and the total norm of sodium carbonate and sodium metasilicate salts on the chemical composition and degree of precipitation of sodium silicofluoride was research. It is shown that the optimal norm of sodium metasilicate is the stoichiometric norm for binding fluorine present in the extraction phosphoric acid to silicofluoride and the total norm of sodium salts is 120-140%, the temperature …

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Modeling Of Craft Oil- Water Emulsion Under Laboratory Conditions, Arslanov Sharafutdin, Dengaev Aleksey, Getalov Andrey, Sarigin Boris Oct 2020

Modeling Of Craft Oil- Water Emulsion Under Laboratory Conditions, Arslanov Sharafutdin, Dengaev Aleksey, Getalov Andrey, Sarigin Boris

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this research is to study the possibilities of modeling oil-water emulsion in the laboratory. The study of the ratio of components and conditions of dispersion (formation) of oil-water emulsions on their stability at different settling temperatures using a laboratory model can optimize the separation of oil-water emulsions in field conditions. The possibility of modeling commercial oil and water emulsions in laboratory conditions is investigated, the average diameters of water globules in simulated oil and water emulsions at different times of their formation are determined, and the obtained average globule diameters are compared with the average diameter of …

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The Possibilities Of Using Loess Clay Of Kattabog Deposit In The Production Of Ceramic Products, Ruzibaev Bahrom, Saloxidinova Salima Oct 2020

The Possibilities Of Using Loess Clay Of Kattabog Deposit In The Production Of Ceramic Products, Ruzibaev Bahrom, Saloxidinova Salima

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research was to determine the properties of loess clay in Kattabog deposit (Uzbekistan) to identify possible areas of use. Modern methods of physicochemical analysis are used: spectroscopic, x-ray phase, electron microscopic methods of analysis. The research results showed that the main phases of clay are hydromica, quartz, kaolinite, calcite and orthoclase. Based on the research, it can be stated that the clay of Kattabog deposit has good physical and technical properties and mineralogical composition, which is a valuable raw material for the production of various ceramics, bricks, tiles, majolica and other products.

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Influence Of The Aluminum Oxide Additive On The Phase Composition Of Mullit-Forming Aluminosilicate Minerals, Mkrtchyan Ripsime, Aripova Mastura Oct 2020

Influence Of The Aluminum Oxide Additive On The Phase Composition Of Mullit-Forming Aluminosilicate Minerals, Mkrtchyan Ripsime, Aripova Mastura

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research is to determine the effect of alumina on the phase composition of shale of the Jerdanak deposit and the quartz-pyrophyllite rock of the Baynaksay deposit during high-temperature firing. X-ray phase analysis determined changes in the phase composition of rocks with additives from 5 to 20% aluminum oxide as a result of firing at 1300 and 1400 °C. A comparative analysis revealed the absence of cristobalite formation, a decrease in the quartz content, and an increase in the amount of mullite for shale samples. No positive effect of alumina additives on the phase composition of quartz-pyrophyllite …

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Coordination Compounds Of Copper, Cobalt And Nickel Formates With Formamide And Carbamide, Jumaniyazova Mukaddas, Azizov Tohir Oct 2020

Coordination Compounds Of Copper, Cobalt And Nickel Formates With Formamide And Carbamide, Jumaniyazova Mukaddas, Azizov Tohir

CHEMISTRY AND CHEMICAL ENGINEERING

The synthesis of mixed ligand coordination compounds of copper, cobalt and nickel formates with formamide and urea in an aqueous solution was carried out. The metal content in the complexes was determined by complexometric titration. Using IR spectroscopy, it was proved that the coordination of formamide and urea with the complexing atom is carried out through the oxygen atom of the carbonyl group. The absorption spectrum of coordinated water is also present in the IR spectrum. The nature of the change in the frequency of stretching vibrations of the –OH group in the composition of water indicates its location in …

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Configuration And Competitive Reactivity Of Ligands In Mixed Ligand Complexes Of Dialkylditiophosphates And Aminobenbenzimidazole (Part I: Au, Pt, Ag), Esbergenova Botakoz, Daminova Shakhlo, Kadirova Zuhra, Sharipov Khasan Oct 2020

Configuration And Competitive Reactivity Of Ligands In Mixed Ligand Complexes Of Dialkylditiophosphates And Aminobenbenzimidazole (Part I: Au, Pt, Ag), Esbergenova Botakoz, Daminova Shakhlo, Kadirova Zuhra, Sharipov Khasan

CHEMISTRY AND CHEMICAL ENGINEERING

With the aim of determination of electronic and geometrical structures of mixed-ligand complexes, theoretical modeling of the structures of coordination compounds of transition metals with dialkyldithiophosphate chelating ligands with aminobenzimidazoles carried out using quantum chemical methods. Using BIOVIA Materials Accelrys Studio 2017 software packages, the geometry, electron density distribution, and frontier orbitals calculated for the mixed ligand complexes of Au(III), Pt(II), Ag(I), Cu(II), Ni(II), Fe(III), which are necessary for understanding the electronic structure of coordination compounds with chelating ligands.

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Educational Cluster - Foundation Of The National Economy And Regional Innovation System, Usmonov Botir, Kushiev Khabibjon Oct 2020

Educational Cluster - Foundation Of The National Economy And Regional Innovation System, Usmonov Botir, Kushiev Khabibjon

CHEMISTRY AND CHEMICAL ENGINEERING

The paper analyzes the available resources for the creation of a cluster approach to the integration of education, science and industry in order to create a mechanism to bring the development of the economy to the level of modern requirements. The article describes the collaboration of science, education and industry through the clustering process. Ways to introduce clustering in the national innovation system are described. At the same time, the role of the integration of education, science and industry with the elements of the National Innovation System is analyzed. In conclusion, the role of the education cluster in the regional …

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Obtaining Microcrystalline Cellulose From Melon Crops And Studying Its Structure, Umarova Vasila, Mardonov Asror, Khamdamova Dilnoza, Akmalova Guzal Oct 2020

Obtaining Microcrystalline Cellulose From Melon Crops And Studying Its Structure, Umarova Vasila, Mardonov Asror, Khamdamova Dilnoza, Akmalova Guzal

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study was to obtain microcrystalline cellulose from gourds. Cellulose was isolated from the stems of watermelon and pumpkin by acid and alkaline heat treatment. Microcrystalline cellulose was obtained from cellulose by hydrolysis. Cellulose was hydrolyzed in a mixture of sulfuric acid and hydrogen peroxide. The optical parameters of the microcrystalline cellulose sample, ash content, bulk density, water swelling, and moisture sorption were determined. The structural features of the obtained microcrystalline cellulose were studied by IR spectroscopy. The functional groups present under various conditions for the production of microcrystalline cellulose were determined. The influence of the duration …

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Radiopaque Activity Of Iodine Containing Methylene-Bis-Carbamate, Baltabaev Ubaydulla, Djuraev Abdukahhor, Abduvakilov Jahongir, Abdullaeva Matluba Oct 2020

Radiopaque Activity Of Iodine Containing Methylene-Bis-Carbamate, Baltabaev Ubaydulla, Djuraev Abdukahhor, Abduvakilov Jahongir, Abdullaeva Matluba

CHEMISTRY AND CHEMICAL ENGINEERING

Considering that many derivatives of bis carbamates have different biological activity, it was intuitive to produce a targeted synthesis of new derivatives of bis carbamates by the interaction of hexamethylene diisocyanate with 3,5-diode-4-hydroxybenzoic acid and 2,4,6-triiodophenol (1: 2 mol, respectively) in freshly distilled dry pyridine at 95-110 оC for 6 hours, the corresponding derivatives were obtained - methylene bis carbamates. Experimental studies have been conducted to identify the acute toxicity and radiopaque properties of the synthesized new N, -hexamethylene bis (2,6-diode-4-carboxyphenylcarbamate).

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