Engineering Commons^™

Two-Photon 3-Dimensional Photoelectrochemical Etching Of Single Crystal Silicon Carbide, Peter Robert Nyholm

Theses and Dissertations

This thesis presents the first use of a novel direct-write, non-line-of-sight, two-photon photoelectrochemical etching technique for etching of single crystal silicon carbide substrates. The use of this technique has resulted in structuring of 3-dimensional structures in high quality single crystal silicon carbide wafers. The 3-dimensional structures demonstrated cannot be formed by any single or combination of traditional silicon carbide machining techniques. This thesis outlines the development of the optical, electrical, and diagnostic components required to achieve two-photon photoelectrochemical etching in silicon carbide. The diagnostic sub-assemblies --a single pixel confocal detector assembly and an in-situ optical microscope assembly-- and their design …

Second-Harmonic Generation Of Structured Light By Transition-Metal Dichalcogenide Metasurfaces, Ling Ling Meng, Xiaoyan Y.Z. Xiong, Tian Xia, Qin S. Liu, Li (Lijun) Jun Jiang, Wei E.I. Sha, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

Structured light characterized by spatially inhomogeneous optical fields found rich applications in optical communication, sensing, microscopy, manipulation, and quantum information. While generation of structured light has been extensively studied in linear optics, the nonlinear optical process, particularly in two-dimensional (2D) materials, is an emerging alternative for generating structured light at shorter wavelengths. In this work, we theoretically demonstrate that radially and azimuthally polarized beams and vortex beams carrying orbital angular momentum could be generated at second-harmonic frequencies by using 2D material-based metasurfaces comprising the same transition-metal dichalcogenide meta-atoms. Manipulation of translations and orientations of anisotropically nonlinear meta-atoms exhibiting a threefold …

Research And Simulation Of Dc Microgrid Three-Phase Ac-Dc Converter Control Strategy Based On Double Loop, Boning Wu, Zhiqiang Gao, Xuesong Zhou, Youjie Ma, Chenglong Wang

Electrical and Computer Engineering Faculty Publications

The new voltage and current double loop control strategy is proposed to solve the DC microgrid bus voltage fluctuation caused by loads fluctuation, parameters perturbation and unbalanced three-phase power supply. Firstly, the dq axis mathematical model of three-phase AC-DC bidirectional converter in DC microgrid is analyzed and established, and then the controllers are designed according to the dq axis mathematical model. The outer loop is a voltage loop based on variable gain linear extended state observer (VGLESO) and sliding mode theory. VGLESO can not only effectively overcome the problem of peak output of traditional high-gain LESO in the initial stage …

College Of Engineering News, Georgia Southern University

College of Engineering & Computing: News & Publications (2010-2023)

• Five Students Win GA Utility Contractors Assoc., Inc. Scholarships

Global Aeolian Dust Variations And Trends: A Revisit Of Dust Event And Visibility Observations From Surface Weather Stations, Xin Xi

Michigan Tech Publications, Part 1

This study revisits the use of horizontal visibility and manually reported present weather (ww) records from the NOAA Integrated Surface Database (ISD) for characterizing the aeolian dust variability and recent trends over the globe and three largest source regions (North Africa, Middle East, and East Asia). Due to its qualitative nature, ww is combined with visibility to derive a new variable, VI, which has higher correlations with the dust emission and burden from satellite observations and global aerosol reanalyses than does the dust event frequency (FR) derived from ww only. Both FR and VI capture …

A Bibliometric Analysis Of Face Anti Spoofing, Swapnil Ramesh Shinde, Shraddha Phansalkar, Sudeep D. Thepade

Library Philosophy and Practice (e-journal)

Face Recognition Systems are used widely in all areas as a medium of authentication, the ease of implementation and accuracy provides it with a broader scope. The face recognition systems are vulnerable to some extent and are attacked by performing different types of attacks using a variety of techniques. The term used to describe the measures taken to prevent these types of attacks is known as face anti spoofing. Research has been carried on since decades to design systems that are robust against these attacks. The focus of the work in this paper is to explore the area of face …

Physical And Chemical Characteristics Of Supramolecular Complexes Of Glycirrizinic Acid With Phytohormones, Djuraev Tulqin, Esanov Rakhmatillo, Gafurov Makhmudjon, Kushiev Khabibjon

CHEMISTRY AND CHEMICAL ENGINEERING

The process of formation of supramolecular complexes of glycyrrhizinic acid with some phytohormones (indolylacetic acid, indolylbutyric acid, α-naphthyl acetic acid and kinetin) were studied with the aim of creation the plant growth stimulator. The complexes structure was studied using IR and UV spectroscopy methods. The prepared compounds described by some physicochemical parameters. The stability constants and stoichiometric composition of complexes were determined in an aqueous solution at pH of 7,2 using UV spectrometry method. In result, all complexes have composition as 1:1 ratio, except the kinetin complex which has 2:1 ratio. The stability constants were equal: KGA:IAA=1,86±1×104; KGA:IBA=2,51±1×103; KGA:NAA =2,70±1×103 …

Study Of The Process For The Removal Of Dyeing Matters Of The Plant Occimum Basilicum L. Lamiaceae, Usmonjonova Khulkar, Atkhamova Saida, Dodaev Kuchkor

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work is dedicated isolation of anthocyanins by ethanol from herbal plant of Occimum basilicum L. Lamiaceae basis. The were studied influencing of temperature, concentration of ethanol to isolation of anthocyanins. There were passed investigations on studying influence level of heating and hydromodule system of rav material-solvent to maximal isolating of anthocyanins. The colors define by fotokolorometrical method at wave length 400-600 nm. There are shown at 540 nm maximal peak of anthocyanins and it is geven as a grapfical diagram. From the obtained depends on content of alcohol in aquatic solution from outlet of colors is …

The Research Of Conditions For The Formation Of Phenol Formaldehyde Resins Modified With Hydroxyl Containg Polyether Polyol, Magrupov Farkhad, Umarov Sherali, Tohirov Murodjon, Radjabova Zukhra

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study was to study the conditions of copolycondensation of phenol alcohol with hydroxyl-containing polyether polyol in the presence of maleic anhydride chain extender in order to obtain modified thermoset phenolic-formaldehyde oligomers. Investigation of the dependence of the content of free phenol, formaldehyde and methylol groups on time during the synthesis of the modified phenol-formaldehyde resin with the ratios hydroxyl-containing polyether polyol:phenol alcohol 1:60 mol/mol and 1:100 mol/mol. It was revealed that maleic anhydride, present in the reaction medium as a copolycondensation catalyst, also participates in copolycondensation reactions as a chain extender. Moreover, as the molar fraction …

Vinylation By 3,6-Dimetyloctin-4-Diol-3,6 Acetylene, Yusupova Lola, Abdukarimova Saida, Rajabov Rustambek, Khalimova Oygul

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research work elaboration of technology of obtaine of acetylene diols and their vinyl ethers. Reaction of formation mono di vinyl ethers as a result vinyl 3,6-dimetyloktin-4-diol-3,6 by acetylene, and also influence of solvents, the catalyst and its quantity, duration of reaction, temperatures is investigated. Are defined speed of reaction. Recommended vinyl 3,6-dimetyloktin-4-diol-3,6 acetylene in the presence of highly basic systems at atmospheric pressure.

Synthesis And Research Of New Heterometal Complexes Cо(Ii), Ni(Ii), Cu(Ii) And Mn(Ii) Based On V(V) And 5-(4-Pyridyl)-1,3,4-Oxadiazole-2(3h)-Thione Lubricants, Pirimova Mehribon, Kadirova Shakhnoza, Rakhmonоva Dilnoza, Ziyayev Abduhakim

CHEMISTRY AND CHEMICAL ENGINEERING

The oxadiazole derivatives complex compounds with metals are biologically active substances. The aim of the study was to study the interaction of the chlorides of Co (II), Ni (II), Cu (II) and Mn (II) with 5-(4-pyridyl)-1,3,4-oxadiazole-2(3H)–thione, ammonium vanadate. Competitive coordination of donor centers, electronic and geometric structures of the ligand molecule were studied on the basis of the quantum-chemical software package Gaussian09 LanL2DZ. It was shown that 5-(4-pyridyl)-1,3,4-oxadiazole-2(3H)-thione ligand is partially coordinated through a localized nitrogen or sulfur atoms at formation of the complex. А procedure was developed for the synthesis of new mixed-metal complexes. The composition and structure of …

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 …

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 …

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.

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 …

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 …

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.

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 …

Study Of Recombinant Protein Fractions From The Bombyx Mori And Pichia Pastoris Using "Native Page" Method, Abdurhakhmanov Jaloliddin, Sasmakov Sobirdjan, Khasanov Shuhrat, Ashirov Оybek

CHEMISTRY AND CHEMICAL ENGINEERING

We have studied the recombinant protein fractions of ̴ 24-34 kDa obtained from Bombyx mori - silkworm larvae and yeast Pichia pastoris. Fractions, containing the recombinant proteins by gel-electrophoresis using the “Native PAGE” method, which allows for differentiation of proteins according to their natural (surface) charge and conformational properties were studied. The results showed that the recombinant protein fraction from Bombyx mori (̴ 34 kDa) consisted of four components and fraction from Pichia pastoris (̴ 24 kDa) consisted one component. The most optimal conditions for the “Native PAGE”- the main gel: Tris HCl (pH-8.8) 244 mM, Bis-Acrylamide 10%, TEMED 0.08%, …

Pressure-Compensated Temperature Control In Rectification Column, Norkobilov Adham, Turakulov Zafar, Kamolov Azizbek, Talipov Hojiakbar

CHEMISTRY AND CHEMICAL ENGINEERING

The focus of this work is to study the control of a rectification column (RC) for separating n-butane (nC4) and n-pentane (nC5) mixtures. Two control structures based on conventional temperature control (TC) and pressure-compensated control (PTC) structures are studied and compared using Aspentech software. The control performance of TC and PTC are investigated in terms of the control of component purities in both distillate and bottoms streams, under various disturbances in feed and pressure conditions. Due to pressure compensation, PTC is superior to TC in terms of purity and impurity control under disturbances in feed and pressure conditions. Accordingly, simulation …

Research Of Kinetic Characteristics Of The Process Of Decomposition Of Zinc Concentrate With Hydrochloric Acid, Rosilov Mansur, Deng Tianlong, Usmanov Ilham, Samadiy Murodjon

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study was the theoretical justification of the kinetic characteristics of the process of producing zinc chloride from zinc concentrate of the Khandiza deposit. For this, the effect of temperature and duration of the process of autoclave zinc extraction in a 28% hydrochloric acid solution was studied at a ratio of Zn: HCI = 1:1.1. Variable parameters were the temperature of 70, 80 and 90 °C and the duration of the leaching process of 6, 8 and 10 hours. The optimal parameters for the production of zinc chloride were determined.

The Study Of The Component Composition Of The Reaction Mixture Containing Formaldehyde Reaction Products, Hurramov Lochinbek, Alimukhamedova Nozima, Adilov Ravshan, Alimukhamedov Muzafar

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to study the effect of the conditions of the reaction of monoethanolamine (Meol) with formaldehyde (FD) on the composition of the reaction mixture. Interaction of monoethanolamine with formaldehyde leads to the formation of N,N’,N”-tris(β-oxyethyl) hexahydro-S-triazine or N,N-bisoxazolidine. The type of final product was determined by the conditions of the reaction and the molar ratio of aminoalcohol:formaldehyde. The chromatogram of the vacuum-distilled final product obtained at the molar ratio of monoethanolamine:formaldehyde=1:1 shows on an individual compound with a retention time of 4.173 s. With increase in the molar ratio of monoethanolamine:formaldehyde=1: 2, the final product …

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 …

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).

Modification Of Lithium Lubricants, Azimova Shodiyakhon, Arslanov Sharafutdin, Aripdjanov Oybek, Azimov Dilmurod

CHEMISTRY AND CHEMICAL ENGINEERING

The aim is to study the effect of the presence of free alkalis and acids on the properties of the complex lithium greases and the choice of the optimal dispersion medium, which provides the required physicochemical characteristics of the developed grease. The dispersed phase of lithium greases studied in the polyalphaolefin oils media. It was found that the use of a mixture of polyalphaolefin oil-4 and polyalphaolefin oil-40 as a percentage of 23/77 with a total content of 83.0% provides a relatively low effective viscosity of the lubricant at low temperatures and a relatively high tensile strength at high temperature.

Effective Oil Extraction From Bombyx Mori Silkworm Pupae And Its Structural Characteristics, Avazova Oynavod, Yugai Sveta, Rashidova Sayora

CHEMISTRY AND CHEMICAL ENGINEERING

The conditions for the effective isolation of oil from the silkworm Bombyx mori pupae, based on the extraction of extracted oil with organic reagents, have been studied. The quantitative content of oil was determined in the samples. It is revealed that the oils extracted using gasoline have a high fat-wax composition compared with ethyl alcohol and hexane. When dried pupae processed with gasoline, it is possible to extract up to 16% of fatty substances as much as possible. Physical-chemical characteristics of the oil from silkworm pupae are characterized by high quality indicators. In particular, the presence of unsaturated fatty acids …

Composition Of Liquid Paraffins For Flotation Enrichment Of Potassium Chloride, Vaqqosov Sobir, Xolmuratov Shamsitdin, Buxarov Shuhrat, Kodirov Orifjon

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this work is to determine the source of liquid paraffins from secondary products of the local chemical industry, compare the performance properties and use the resulting products as apolar co-reagents in silvinite flotation. The experiments were conducted with secondary used hexane and pyrocondensation. To improve the efficiency of flotation, the dependences of the order of reagent’s supply into the process and the time of action were studied. Experiments have shown that when adding tetradecane and pentadecane in an amount of 2.5 to 7.5% to hexane liquid paraffins, it is possible to reduce the tail of KCl to …

Influence Of Technological Parameters On The Chemical Composition Of Calcium Polyphosphates From Phosphorites Central Kyzylkum, Ulugberdieva Ziyada, Khujamberdiev Sherzod, Mirzakulov Kholtura, Usmanov Ilkham

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research was to study the effect of temperature, the ratio of P2O5EPA:P2O5PRM and the duration of calcination on the content of various forms of P2O5 in calcium polyphosphate. The effect of calcination temperature from 150 to 300 °C, the ratio of P2O5EPA:P2O5FRM from 2,15 to 4,50 and the duration of the process from 20 to 120 minutes on the changes in various forms of P2O5 were studied. It was shown that with increasing temperature to 200-250 °C the content of the total (ortho + poly) assimilable form of Р2О5 increases and then decreases, passing through a …

Bases Of Development Of Technologies Of Synthesis Of Oxide Materials In Big Solar Furnace (Parkent), Gulamova Dilbara, Baxronov Khayot, Bobokhulov Sirojiddin, Eshonkulov Elyor

CHEMISTRY AND CHEMICAL ENGINEERING

The advantages of synthesis of complex oxide compounds by solar energy, the possibility of obtaining highly textured nano materials are shown. The development of heliomaterial science, aimed at the synthesis of new materials, is inextricably linked with the use of effective optical energy systems. On the example of obtaining superconducting materials of nominal composition Bi1.7Pb0.3Sr2Ca(n-1)CunOy (n = 3-20), optimization of the parameters of the optical-energy system of the Big Solar Furnace (Parkent) is shown. The ideology of developing heliotechnology for the synthesis of inorganic materials in a solar furnace is presented. The properties of a superconducting material of nominal Bi1.7Pb0.3Sr2Ca(n1)CunOy …

Synchronverter-Based Control Of Multi-Port Autonomous Reconfigurable Solar Plants (Mars), Phani R.V. Marthi, Suman Debnath, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Control of integrated photovoltaic (PV) plants with energy storage systems (ESSs) has become an important research and development topic in recent times. In this context, a Multi-port Autonomous Reconfigurable Solar (MARS) plant that integrates PV and ESS to alternating current transmission grid and high-voltage direct current (HVdc) link is studied in this paper. With penetration of power electronic based resources in the grid, the grid's capability to recover from frequency or voltage disturbances are reduced. Therefore, one of the vital objectives of any new grid integrated power electronic resource is to provide advanced control functions like voltage and frequency support …