Engineering Commons^™

Conducted Emi Mitigation In Power Converters Using Active Emi Filters, Balaji Narayanasamy

Graduate Theses and Dissertations

Wide bandgap devices enable high power density power converters. Despite the advantages of increased switching frequency, the passive components are still a major bottleneck towards enabling high power density. Among the passive components in the converter, the passive EMI filters are unavoidable to ensure compliance with conducted EMI standards. Active EMI filters help reduce the volume of the passive components and have been around for three decades now. Firstly, this work presents a summary of all the different active EMI filters based on the type of noise-sensing, noise-processing, the type of active circuits used and the type of control methods. …

Towards High Efficiency And High Power Density Converter: System Level Design, Modulation, And Active Emi Filters, Hongwu Peng

Graduate Theses and Dissertations

Power converter exposes strong challenges to its efficiency, power density and reliability. For the grid-connected inverter application, three-level (3-L) T-type neutral-point-clamped (TNPC) inverters has higher efficiency and lower total harmonic distortion (THD) compared to two-level inverter. Hybrid switch concept combines the benefit of both silicon carbide (SiC) MOSFET and Si IGBT. By applying hybrid switch structure in 3-L T-type inverter, the total power density of 3-L TNPC inverter will be higher while the cost will be lower than that of all-SiC 3-L T-type inverter. The hybrid switch based 3-L TNPC inverter also imposes challenge to its modulation and control, a …

Development Of A Reference Design For A Cyber-Physical System, Nicholas Paul Blair

Graduate Theses and Dissertations

The purpose of this thesis is to develop a reference design to assist in the selection of security practices in power electronics design. A prototype will be developed from this reference design for evaluation. This evaluation will include a brief cost/benefit analysis to gauge the efficacy of implementing each layer of security throughout the power electronics design process. This thesis will also describe the obstacles and effectiveness of integrating a Trusted Platform Module (TPM) into a cyber-hardened grid-connected device. The TPM device is a secured crypto processor that assists in generating, storing, and restricting the use of cryptographic keys. The …

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 …

The Impact Of Composition And Morphology On Ionic Conductivity Of Silk/Cellulose Bio-Composites Fabricated From Ionic Liquid And Varying Percentages Of Coagulation Agents., Bailey Blessing, Cory Trout, Abneris Morales, Karleena Rybacki, Stacy A Love, Guillaume Lamoureux, Sean M O'Malley, Xiao Hu, David Salas-De La Cruz

College of Science & Mathematics Departmental Research

Blended biocomposites created from the electrostatic and hydrophobic interactions between polysaccharides and structural proteins exhibit useful and unique properties. However, engineering these biopolymers into applicable forms is challenging due to the coupling of the material’s physicochemical properties to its morphology, and the undertaking that comes with controlling this. In this particular study, numerous properties of the Bombyx mori silk and microcrystalline cellulose biocomposites blended using ionic liquid and regenerated with various coagulation agents were investigated. Specifically, the relationship between the composition of polysaccharide-protein bio-electrolyte membranes and the resulting morphology and ionic conductivity is explored using numerous characterization techniques, including scanning …

Final Report - Bridge Resilience Assessment With Inspire Data, Iris Tien, Yijian Zhang

Project RR-1

This project proposed a methodology to assess the impact of corrosion on the performance of bridges. The combined analytical and numerical modeling of shear-critical and lap-spliced columns is detailed, and outcomes are verified with previous experimental test data. The impact of corrosion on risk is assessed through conducting fragility analyses. Results quantify the increase in failure probabilities of these structures, measured by increasing probabilities of exceeding defined damage states, with increasing levels of corrosion. Corrosion is found to have a larger impact on increasing probabilities of exceeding more severe damage states. Twenty percent mass loss of reinforcement increases the probability …

Long-Term Durability Of Solar Photovoltaic Modules, Chibuisi Chinasaokwu Okorieimoh, Brian Norton

Conference papers

Solar photovoltaic (PV) panels experience long-term performance degradation resulting in lower like-per-like efficiencies and performance ratios when compared with their initial performance. Manufacturers of solar photovoltaic modules usually guarantee the life span for more than 20 years. It is therefore necessary to track and mitigate degradation of PV modules over this period to satisfy such guarantees and beyond this period to identify maintenance and repair requirements. Degradation of solar PV modules makes them less efficient, less reliable and, ultimately, inoperative. This paper reviews relevant literature to discuss:

• Causes of efficiency reductions in photovoltaic cells

• Ways to achieve long-term durability of …

Relational Joins On Gpus For In-Memory Database Query Processing, Ran Rui

USF Tampa Graduate Theses and Dissertations

Relational join processing is one of the core functionalities in database management systems. Implementing join algorithms on parallel platforms, especially modern GPUs, has gain a lot of momentum in the past decade. This dissertation addresses the following issues on GPU join algorithms. First, we present empirical evaluations of a state-of-the-art work on GPU-based join processing. Since 2008, the compute capabilities of GPUs have increased following a pace faster than that of the multi-core CPUs. We run a comprehensive set of experiments to study how join operations can benefit from such rapid expansion of GPU capabilities. We also present improved GPU …

Moving Targets: Addressing Concept Drift In Supervised Models For Hacker Communication Detection, Susan Mckeever, Brian Keegan, Andrei Quieroz

Conference papers

Abstract—In this paper, we are investigating the presence of concept drift in machine learning models for detection of hacker communications posted in social media and hacker forums. The supervised models in this experiment are analysed in terms of performance over time by different sources of data (Surface web and Deep web). Additionally, to simulate real-world situations, these models are evaluated using time-stamped messages from our datasets, posted over time on social media platforms. We have found that models applied to hacker forums (deep web) presents an accuracy deterioration in less than a 1-year period, whereas models applied to Twitter (surface …

Synthesis And Characterization Of Novel Silicone Hydrogel Biomaterials With Advanced Properties For Ocular Drug Delivery, Liana D. Wuchte

Theses and Dissertations

There is a need for next generation silicone hydrogel biomaterials with greater compositional flexibility and tailorable material properties for advanced manufacturing and new applications for ocular drug delivery. Poly(DMS-R11-co-TRIS-co-DMA-co-PEG200DMA-co-DEAEM-co-DADMAC) silicone hydrogel contact lenses were synthesized with macromolecular memory and showed 7-day in vitro release of latanoprost acid via a microfluidic platform with controlled release and improved drug payload capacity compared to control lenses. Six newly synthesized silicone macromers were then incorporated into contact lens formulations for the first time to produce a novel, improved platform. Various silicone macromer structures showed significantly improved solubility with TRIS and DMA with components ranging …

Mining The Borderlands: Industry, Capital, And The Emergence Of Engineers In The Southwest Territories, 1855-1910. Grossman, Sarah E.M. University Of Nevada Press, 2018, James Altman

Executive Vice President & Provost Faculty Research

In Mining the Borderlands: Industry, Capital, and the Emergence of Engineers in the Southwest Territories, 1855‐1910, distinguished scholar Sarah E.M. Grossman examines the early history of commercial mining along the US‐Mexico border. She brings to the task her extensive knowledge of the region, and a forensic detective's thirst for the truth. Her mission is to understand precisely how much, and in what specific ways, various commercial mining ventures in the desert Southwest contributed not only to the economic development of the region, but also to improvements in mining techniques, engineering methods, equipment, efficiency, working conditions, mining education, and most importantly, …

Influence Of Deposition Temperature On Properties Of Multilayered Gallium Doped Zinc Oxide Films Prepared By Dc Magnetron Sputtering Technique, Elisante Maloda, Anayesu Malisa

Tanzania Journal of Science

Multilayered transparent conducting films based on ZnO: Ga were deposited onto glass substrate by DC magnetron sputtering technique. The films were prepared from alloy (Zn: Ga) and ceramic (ZnO: Ga) targets with gallium composition of 3 at% and 4 at%, respectively. Crystal structure and phase analysis were measured using X-ray diffractometer (XRD). The XRD structural analysis results indicated that all multilayered films were polycrystalline with (002) orientation slightly shifted of diffracting angles due to gallium dopant concentrations as increase in the deposition temperatures. The films were hexagonal wurtzite structure, having preferred growth orientation in c-axis perpendicular to the substrate surface. …

Modeling And Control Of Solar Pv With Battery Energy Storage For Rural Electrification, Irene Masenge

Tanzania Journal of Engineering and Technology (TJET)

In rural areas where electric power grid network is rarely available, power generation from renewable energy resource such as solar photovoltaic (PV) is mostly accomplished in standalone mode. The standalone solar PV system requires energy storage device to achieve reliable power supply to the end users. This paper presents modelling and coordination control of solar PV with battery energy storage system (BESS) for rural-electrification applications. The proposed control is accomplished via a bidirectional buck-boost converter with the objective of maintaining voltage at the DC bus constant. Simulation results based-on MATLAB/Simulink platform confirms good performance of the proposed system

Performance Analysis Of Renewable Energy Resources In Rural Areas: A Case Study Of Solar Energy, Jackson Justo

Tanzania Journal of Engineering and Technology (TJET)

This paper presents an overview of the recent development trends of solar photovoltaic (PV) systems and the performance in the Tanzanian context. The two types of solar power generation that are considered in this paper are: i) solar PV systems and ii) concentrated solar power (CSP). The two are compared in terms of cost of energy and energy storage mechanism. Moreover, the effect of ambient temperature on the solar PV module is analyzed. In addition, a detailed analysis on using solar axis tracking to increase the power generation is also presented. The extent to which the cell surface temperature and …

Comminution Characteristics Of Lithium Bearing Mica Ores From Different Devices, Alphonce Wikedzi

Tanzania Journal of Engineering and Technology (TJET)

This paper highlights on the comminution and to the lesser extent liberation properties of two greisen-type lithium bearing-mica ores (L1, L2) subjected to different breakage devices; cone crusher (CC), roller crusher (RC), rotor beater mill (RBM) and a screen mill (SM). The particle size distributions (PSD) of the products from each device were evaluated to search for an appropriate PSD model using Gates-Gaudin-Schuhmann (GGS) and Rosin-Rammler (RR) functions. To determine an appropriate function, coefficients of determination (R2) were used as a criterion. Due to budget constraint, only products from rotor beater mill (RBM) were examined for mineral liberation by an …

Estimating Flood Magnitudes Of Ungauged Urban Msimbazi River Catchment In Dar Es Salaam, Tanzania, Patrick Valimba Dr

Tanzania Journal of Engineering and Technology (TJET)

More often daily climate data have been used in hydrological models to estimate flood flows in small data scarce urban and rural catchments where flow peaking and recession are quick within short periods of few hours. This study assesses magnitudes of error of using daily climate data to simulate flood flow hydrographs of a small urban river catchment, Msimbazi River. Spot discharge measurements were available for Apr-May 2014 and Mar May 2015 periods.10-minutes climate records were available at one station, daily temperatures at two stations while daily rainfall records at several stations within the catchment. Visual analysis characterise rainfall events …

Spatial And Temporal Variation Of Rainfall And Streamflow In The Kikuletwa Catchment Of Upper Pangani Basin, Tanzania, Upendo Msovu

Tanzania Journal of Engineering and Technology (TJET)

Streamflow and rainfall records from 1980 to 2015 as a (common period for the analyzed stations) were used to analyze the variations of rainfall and streamflow in the Kikuletwa catchment. Also, the analysis of the longest time series available at each station up to 2015 (referred to as the whole series in this study) was conducted to relate past rainfall and streamflow changes, at the tributaries of Kikuletwa River located above the Rundugai natural springs as recommended from previous studies. Various methods such as simple statistics of the mean, standard deviation, coefficient of variance, and graphs were used to analyze …

Blind Image Quality Assessment For Face Pose Problem, Cerine Tafran, Mohamad El-Abed, Ziad Osman, Islam Elkabani

BAU Journal - Science and Technology

No-Reference image quality assessment for face images is of high interest since it can be required for biometric systems such as biometric passport applications to increase system performance. This can be achieved by controlling the quality of biometric sample images during enrollment. This paper proposes a novel no-reference image quality assessment method that extracts several image features and uses data mining techniques for detecting the pose variation problem in facial images. Using subsets from three public 2D face databases PUT, ENSIB, and AR, the experimental results recorded a promising accuracy of 97.06% when using the RandomForest Classifier, which outperforms other …

Studies Of Smba2cu3o7-Δ / Znfe2o4 Superconducting Composites, Hadi Basma, Waleed Abdeen, Ayman El-Tahan, El-Maghraby El-Maghraby, Ahmed Khalaf

BAU Journal - Science and Technology

SmBa2Cu3O7-δ /(ZnFe2O4)x superconducting composites with 0.00 ≤ x ≤ 0.20 wt% were prepared by the usual solid-state reaction method. The prepared samples were investigated using X-ray powder diffraction (XRD) at room temperature and electron paramagnetic resonance (EPR) measurements in the temperature range (100-295 K). It is found that EPR spectra are dominated by an anisotropic Cu2+ EPR pattern. Moreover, the EPR spectral intensity increases as the temperature decrease from room temperature down to 100 K. The number of spins (N) participating in EPR resonance, the activation energy (Ea), the paramagnetic susceptibility (c) and the effective magnetic moment (µeff) are calculated …