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Articles 7591 - 7620 of 196021

Full-Text Articles in Engineering

An Inexpensive, Open, And Extensible Hardware-In-The-Loop Cubesat Test And Simulation Infrastructure, Andrew Greenberg, Glenn Lebrasseur, Max Eltzroth, Rose Edington, Anna Meneely, Maxwell Millar Aug 2025

An Inexpensive, Open, And Extensible Hardware-In-The-Loop Cubesat Test And Simulation Infrastructure, Andrew Greenberg, Glenn Lebrasseur, Max Eltzroth, Rose Edington, Anna Meneely, Maxwell Millar

Small Satellite Conference

We have developed an inexpensive, open source, and extensible hardware-in-the-loop (HIL) test and simulation system to allow even small CubeSat teams to dramatically improve their testing infrastructure to increase reliability during flight.


7e And Sustainability Analysis Of Photovoltaic Thermal System (Pvt) Incorporating Graphene And Al2o3 Nano-Particles With Paraffin Wax Integrated Fin Arrangements, Md Shahriar Mohtasim, Utpol K. Paul, Md Golam Kibria, Barun K. Das Aug 2025

7e And Sustainability Analysis Of Photovoltaic Thermal System (Pvt) Incorporating Graphene And Al2o3 Nano-Particles With Paraffin Wax Integrated Fin Arrangements, Md Shahriar Mohtasim, Utpol K. Paul, Md Golam Kibria, Barun K. Das

Research outputs 2022 to 2026

The efficiency and electricity production of a solar photovoltaic (PV) system are significantly influenced by the temperature of the PV module. Numerous studies have incorporated nanomaterials into phase change materials (PCM) integrated with PV systems to enhance thermodynamic performance; however, life-cycle aspects and the 7E sustainability indicators remain largely unaddressed. No study has yet explored paraffin wax hybridized with Al2O3 and graphene nanomaterials in specific ratios within a photovoltaic thermal (PVT) and fin system at an optimal fluid flow rate. Three different scenarios have been explored in this study, including a PVT/PCM system with a water-flowing fluid, a PVT/Fin arrangements/hybrid …


Retracted: Mathematical Properties And Simulations Of The Neutrosophic Gompertz-Inverse Burr-X Distribution With Application To Under-Five Mortality, Mustafa Hassan Jumaa, Asmaa S. Qaddoori, Sara A. Khalaf, Nooruldeen A. Noori, Mundher A. Khaleel Aug 2025

Retracted: Mathematical Properties And Simulations Of The Neutrosophic Gompertz-Inverse Burr-X Distribution With Application To Under-Five Mortality, Mustafa Hassan Jumaa, Asmaa S. Qaddoori, Sara A. Khalaf, Nooruldeen A. Noori, Mundher A. Khaleel

Iraqi Journal for Computer Science and Mathematics

Despite significant progress in the development of statistical distributions, there remain clear gaps in modelling complex datasets, such as those involving uncertainty or requiring flexible representations of multidimensional variables. This study introduces a new distribution the Neutrosophic Gompertz-Inverse Burr-X (NGoIB-X) distribution to address these challenges. The model is based on the Neutrosophic Gompertz family (NGo-G), which itself employs the T-X method in its formulation. Characterised by four Neutrosophic parameters and a Neutrosophic random variable, the NGoIB-X distribution offers enhanced flexibility for representing and analysing uncertain data. The theoretical properties of the NGoIB-X distribution are explored, including its Neutrosophic probability density …


A New Lightweight Encryption Method Based On The Dna-Rc4 Substitution For Resource-Constrained Iot Devices, Athraa J. H. Witwit, Ahmed Fanfakh, Ali Kadhum Idrees Aug 2025

A New Lightweight Encryption Method Based On The Dna-Rc4 Substitution For Resource-Constrained Iot Devices, Athraa J. H. Witwit, Ahmed Fanfakh, Ali Kadhum Idrees

Iraqi Journal for Computer Science and Mathematics

Technology's impact on daily life necessitates increased data protection. Cryptographic systems improve security, ensuring confidentiality and legitimacy of Internet of Things systems. However, resource-constrained devices face challenges like memory, battery life, processing power, and small size. In light of this, lightweight cryptography (LWC) provides techniques specifically tailored to the constraints of resource-constrained Internet of Things devices. However, the presence of a fixed S-Box in some LWC algorithms, such as Advanced Encryption Standard, or the absence of one in others, such as Speck and Tiny Encryption Algorithm, renders them more susceptible to attacks. In this paper, we suggest a new lightweight …


Hybrid Organic–Inorganic Corrosion Inhibitors: Bridging Performance And Eco-Safety, Hasan M. Luaibi, Saja S. Al-Tweel Aug 2025

Hybrid Organic–Inorganic Corrosion Inhibitors: Bridging Performance And Eco-Safety, Hasan M. Luaibi, Saja S. Al-Tweel

AUIQ Technical Engineering Science

Corrosion leads to global economic losses exceeding $2.5 trillion annually and accounts for up to 30% of infrastructure failures. Conventional corrosion inhibitors face limitations such as aquatic toxicity (LC50 <100 mg/L), moderate efficiencies (65–82%), and poor long-term durability (<500 hours). This review critically evaluates hybrid organic–inorganic corrosion inhibitors, focusing on their composition, mechanisms, performance metrics, and eco-safety. Hybrid systems comprising organic molecules integrated with inorganic matrices like sol–gel networks, nanocomposites, and layered double hydroxides (LDHs) demonstrate enhanced functionality through barrier effects, self-healing, and controlled release. These materials achieve inhibition efficiencies of 88–98.5%, outperforming conventional systems by 18–35%. Sol–gel coatings protect carbon steel at 92–98% efficiency in 3.5% NaCl, while LDHs sustain 94–97% protection over 1200–1500 hours. Nanocomposites reduce corrosion rates from 0.95 mm/year to 0.002–0.004 mm/year. Electrochemical techniques (EIS, PDP) show increased charge transfer resistance (500–2500 Ω·cm2) and coating resistance up to 108 Ω·cm2. Surface analysis reveals smoother films (Ra = 15–35 nm), higher contact angles (95–125°), and adhesion strengths of 12–18 MPa. Case studies report 90–96% protection in marine settings, 88–94% in acidic media, and over 92% under atmospheric conditions. Durability tests confirm >90% efficiency after 1000 hours, significantly higher than the <60% for conventional coatings. Overall, hybrid inhibitors offer a high-performance, eco-conscious alternative for corrosion control, combining efficiency, environmental safety, and scalability. Their superior metrics and adaptability position them as next-generation solutions for diverse industrial applications.


Demystifying The Discharge Coefficient For Flow Over Thin Weirs And Sills, Joseph E. Pugh, Subhas Karan Venayagamoorthy, Timothy K. Gates Aug 2025

Demystifying The Discharge Coefficient For Flow Over Thin Weirs And Sills, Joseph E. Pugh, Subhas Karan Venayagamoorthy, Timothy K. Gates

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A revised derivation of the discharge coefficient for flows over thin weirs and sills in the limits of wall overflow to a free overfall is given. Using dimensional analysis, we show that the discharge coefficient, (Formula presented), in the classical weir-discharge equation is best understood as a weir Froude number, (Formula presented), which accounts for the combined effects of inertia, contraction and viscous energy losses within the flow field. A comprehensive set of experimental data from historical studies is complimented by new data from the authors, featuring both laboratory flume experiments and three-dimensional numerical simulations of weir flows. Synthesis of …


Scalable And Adaptive Agile Framework For Semiconductor Foundry: Advanced Packaging And Heterogeneous Integration Perspective, Pravin Thorat Aug 2025

Scalable And Adaptive Agile Framework For Semiconductor Foundry: Advanced Packaging And Heterogeneous Integration Perspective, Pravin Thorat

Harrisburg University Dissertations and Theses

This research addressed the critical requirement for a scalable and adaptive agile framework specifically designed for the unique demands of semiconductor foundries specializing in advanced packaging and heterogeneous integration (HI). The semiconductor industry was encountering growing pressure to innovate and respond quickly to rapidly evolving demands, yet traditional manufacturing processes often struggled to adapt. Existing agile frameworks, mainly developed for the software industry, lacked the necessary adaptations to address the complexities of semiconductor manufacturing, including extended lead times, high capital investment, rigorous quality requirements, and the integration of various technologies. This research gap hindered the ability of semiconductor foundries to …


Streamlining The Cleaning And Analysis Of Eye Tracking Data For Cross-Recurrence Analysis, Michael V. Rosalia Aug 2025

Streamlining The Cleaning And Analysis Of Eye Tracking Data For Cross-Recurrence Analysis, Michael V. Rosalia

McNair Summer Research Program

The use of multimodal data to understand and support collaborative learning has grown in popularity recently as it allows researchers to study complex learning tasks from different facets. However, multimodal analysis is often computationally complex and often requires a strong set of technical skills and mathematical understanding to clean and process the data, creating barriers that restrict researchers without advanced programming skills from conducting these analyses. There are existing software packages that can help with this process, but they are often piecemeal requiring the user to understand how to put them together and what best practices may entail. This can …


Wear Of High Entropy Alloys: Understanding Effects Of Cryogenic Temperatures And Surface Nitriding On Wear Behavior, Aubrey Yu Tang Aug 2025

Wear Of High Entropy Alloys: Understanding Effects Of Cryogenic Temperatures And Surface Nitriding On Wear Behavior, Aubrey Yu Tang

Dartmouth College Ph.D Dissertations

Cryogenic tribological applications have become increasingly important with the development and innovation of advanced equipment in aerospace, polar regions, superconductivity, and more. Traditional lubrication methods are not viable under these harsh environments, so metallic materials must be able to maintain excellent mechanical properties and withstand the constant impact and wear alone. High entropy alloys (HEAs) have emerged as potential candidates for these applications because of their wide variety of excellent room temperature properties and apparent improvement of mechanical properties of some HEAs at extremely low temperatures. Despite their promising nature, very limited work has been done on understanding the wear …


Development And Optimization Of Gradient Pore Structured Porous Ceramics: Modeling, Properties, And Potential For Industrial Production In Thermal Insulation Engineering, Gang Qi, Minghui Li, Ruoyu Chen, Haichuan Wang, Haiming Wen, Yi Ding, Xiaoyu Xia, Dixin Yan, Can Chen, Saisai Li Aug 2025

Development And Optimization Of Gradient Pore Structured Porous Ceramics: Modeling, Properties, And Potential For Industrial Production In Thermal Insulation Engineering, Gang Qi, Minghui Li, Ruoyu Chen, Haichuan Wang, Haiming Wen, Yi Ding, Xiaoyu Xia, Dixin Yan, Can Chen, Saisai Li

Materials Science and Engineering Faculty Research & Creative Works

This study prepared gradient pore structure ceramics from silica fume through direct foaming. The rheological behavior of the slurry was improved by varying the solids content. Physical and mathematical models were developed to describe the longitudinal movement of foam in the ceramic slurry and the mechanism of gradient pore formation. These models were used to predict the pore sizes at different heights within the ceramic. Insulation and mechanical properties were enhanced by optimizing the gradient pore structure. The gradient pore structure resulted in significant directional differences in specimen properties. Additionally, suitable sintering-temperatures for gradient pore structure ceramics are discussed. The …


Enhanced Global Oil Spill Dataset From 1967 To 2023 Based On Text-Form Incident Information, Yiming Liu, Zhuoli Yin, Hua Cai Aug 2025

Enhanced Global Oil Spill Dataset From 1967 To 2023 Based On Text-Form Incident Information, Yiming Liu, Zhuoli Yin, Hua Cai

The School of Sustainability Engineering and Environmental Engineering (SEE) Faculty Publications

Knowing how much oil was released into the environment in each incident is critical to studying the environmental, ecological, and economic impacts of oil spills. However, the release amounts (RAs) for numerous oil spill incidents remain unavailable in a structured format for large-scale analysis. The most extensive global oil spill database, managed by NOAA’s Office of Response and Restoration, only documents the worst-case scenario estimations in the machine-readable dataset, while more accurate values are embedded within unstructured incident descriptions and subsequent updates. To enhance the dataset with more accurate RAs, we developed a framework to extract the actual RAs from …


Exploring The Role Of Accessibility In Enhancing User Experience: Trends, Challenges, And Opportunities Across Digital Platforms, Adiba Khan Aug 2025

Exploring The Role Of Accessibility In Enhancing User Experience: Trends, Challenges, And Opportunities Across Digital Platforms, Adiba Khan

Harrisburg University Dissertations and Theses

Accessibility was a fundamental aspect of enhancing user experience (UX) across digital platforms, ensuring equitable access to information and services for a diverse range of users, including individuals with visual, auditory, cognitive, or motor impairments. As digital products became increasingly central to education, commerce, and communication, the need for inclusive design grew. This study explored the intersection of accessibility and UX, with a specific focus on how accessibility-driven design improved usability, user satisfaction, engagement, and the overall quality of digital interactions. Grounded in Agile project management principles, the research examined how early integration of accessibility into the software development lifecycle …


Development Of Numerical Tools And Performance Metrics For Analysis Of Optical Particle Counters, Doug Webb Aug 2025

Development Of Numerical Tools And Performance Metrics For Analysis Of Optical Particle Counters, Doug Webb

Theses and Dissertations

Monitoring air quality is essential for understanding and mitigating the health impacts of airborne particulate matter (PM), which is linked to respiratory and cardiovascular disease. Optical particle counters (OPCs) are widely used for air quality monitoring, yet their precision and accuracy remain uncertain due to inconsistent performance evaluations. In this thesis, performance metrics are developed that can be used to assess the accuracy of OPCs in measuring PM concentrations and size distributions. Computational fluid dynamics (CFD) simulations are employed to analyze the behavior of particle-laden air streams through representative OPC models. The impact of design parameters is quantified using newly …


64th Annual Rocky Mountain Conference On Magnetic Resonance Aug 2025

64th Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 64th annual meeting of the Rocky Mountain Conference on Magnetic Resonance. Held in the Snowbird Resort and Conference Center, Snowbird, Utah, August 3-7, 2025.


Tracing Tremor: From Upper-Limb Neuromusculoskeletal Dynamics To Movement Signatures In Essential Tremor, Landon J. Beutler Aug 2025

Tracing Tremor: From Upper-Limb Neuromusculoskeletal Dynamics To Movement Signatures In Essential Tremor, Landon J. Beutler

Theses and Dissertations

Tremor is a common neurological condition that significantly impairs the quality of life for millions. Despite this prevalence, the underlying mechanisms of its propagation remain poorly understood, and current treatment options often rely on trial-and-error methods. Moreover, the most common type, Essential Tremor (ET), presents a unique challenge due to its heterogeneity--patients exhibit a wide range of symptoms, severities, and responses to treatment. This thesis primarily advances tremor understanding through computational modeling, with a secondary focus on data-driven subtyping of ET via cluster analysis. These parallel paths aim to improve both mechanistic insight and clinical classification. Tremor propagation refers to …


Design Of A Fan-Based Test Stand For Evaluating Multicopter Handling In Turbulent Flow, Salim Roig Aug 2025

Design Of A Fan-Based Test Stand For Evaluating Multicopter Handling In Turbulent Flow, Salim Roig

Doctoral Dissertations and Master's Theses

With the innovation of eVTOL rotorcraft the need to analyze how turbulence-induced disturbances from orthogonal flow affect various rotorcraft configurations outside of simulations have grown significantly. To investigate the behavior of this type of flow and how it interacts with various rotorcraft configurations, a turbulent inducing test stand was designed and constructed. The test stand will have two walls of computer fans arranged in an L-shape frame, creating wind gusts that simulate the non-linear turbulent wind experienced by eVTOL. This also aids the Eagle Flight Research Center (EFRC) in their efforts to better understand how disturbances affect the handling qualities …


Development Of Low-Cost Small-Batch Flibe Filtration, And A Comparison Of Uranium Tetrafluoride And Ionic Oxygen Oxidation In Flibe, Jacob D. Christensen Aug 2025

Development Of Low-Cost Small-Batch Flibe Filtration, And A Comparison Of Uranium Tetrafluoride And Ionic Oxygen Oxidation In Flibe, Jacob D. Christensen

Theses and Dissertations

Low-cost benchtop-scale molten fluoride salt cleaning was investigated in FLiBe (LiF-BeF2), focusing on electrochemical cleaning and filtration. FLiBe filtration was demonstrated using both pressurized and open filtration systems. Copper and 400 Monel meshes were effective and reusable. Wetting appears to be the primary obstacle to FLiBe filtration. Oxygen oxidation behavior in FLiBe was examined using cyclic voltammetry (CV) and cyclic square wave voltammetry (CSWV) techniques. Standard addition height measurement was used to determine electrode surface area. Results support a single-step 2-electron process, matching observations in literature. Pt electrodes may be prone to oxidative side reactions, although more investigation is required. …


Towards Applying Artificial Intelligence To Solve Np-Complete Problems Using Quantum Computing, Andrew Robert Haverly Aug 2025

Towards Applying Artificial Intelligence To Solve Np-Complete Problems Using Quantum Computing, Andrew Robert Haverly

Theses and Dissertations

This dissertation explores the methodology for more thoroughly entangling artificial intelligence and quantum computing. This is explored through a background search of problems solved using Grover’s quantum algorithm, a new quantum protein folding and drug discovery algorithm, using Grover’s algorithm to train quantum artificial neural networks, using quantum artificial neural networks for reinforcement learning, mapping classical assembly instructions to quantum circuits to make quantum programming easier, and using prompt engineering to get a classical artificial intelligence agent to solve an NP-Complete problem using a Grover’s algorithm. This method not only simplifies the creation of algorithms but also opens new avenues …


Genetic Algorithm Optimization To Maximize Sensitivity Of Triboelectric Mems Accelerometers, Yu Tian, Benyamin Davaji, Shahrzad Towfighian Aug 2025

Genetic Algorithm Optimization To Maximize Sensitivity Of Triboelectric Mems Accelerometers, Yu Tian, Benyamin Davaji, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

A genetic algorithm is used to optimize the sensitivity of a triboelectric MEMS accelerometer fabricated using CMOS-compatible processes. The optimization focuses on the structural parameters of an awl-shaped serpentine microspring (ASSM) connected to the proof mass. Constraints are defined by microfabrication standards and the available chip area. Three different constraint problems are considered, and the algo- rithm yields designs with maximized sensitivity in each case. Simulations under various sinusoidal vibration scenarios show that the optimized designs significantly outperform the previous version, achieving a 2.72× improvement at 1000 Hz and up to 20× at 500 Hz.


Effect Of Arm Movement On Lower Body Muscle Contributions To Standing Long Jump Performance, Abigail Douglas Aug 2025

Effect Of Arm Movement On Lower Body Muscle Contributions To Standing Long Jump Performance, Abigail Douglas

Masters Theses

Previous jumping studies have proven that jumping with arm motion enhances performance compared to jumping without arm motion. The purpose of this study was to investigate the effect of arm motion on the muscle contributions of the lower extremities during the standing long jump using muscle-actuated modeling informed by experimental data. Specifically investigating how arm motion enhances performance at the muscle level and how the muscle contributions of the lower extremities differ in jumps with and without arm motion. Three male and three female participants performed three jumps with arms and three jumps without arms. The longest jumps with and …


The Effect Of Wall Temperature And Transpiration On Görtler Vortices In High-Speed Boundary Layers, Asmaa Ahaggach Aug 2025

The Effect Of Wall Temperature And Transpiration On Görtler Vortices In High-Speed Boundary Layers, Asmaa Ahaggach

Theses and Dissertations

Görtler vortices are counterrotating flow structures generated as a result of the imbalance between the wall radial pressure gradients and the centrifugal forces in a boundary layer developing on a curved surface. Their presence leads to secondary instabilities and increases the wall shear stress as they accelerate the transition from laminar to turbulent flow. These secondary instabilities can be mitigated using control techniques aimed at decreasing the energy and the wall shear stress. In this thesis, the combined effect of wall temperature and transpiration on Görtler vortices developing in supersonic and hypersonic boundary layers is investigated. Görtler vortices are excited …


Load Balancing For Stream Processing In Edge Computing, Faiza Akram Aug 2025

Load Balancing For Stream Processing In Edge Computing, Faiza Akram

Theses and Dissertations

Unlike cloud-based systems, where resources are centralized for data processing and located at a distance from the source, leading to an increase in the response time, edge computing emerges as a transformative paradigm that processes the data closer to the sources to meet the application’s service requirements. Since the resources in edge computing are distributed and limited, load balancing is crucial. To ensure the prevention of bottlenecks and failures in resource-constrained environments, load balancing is an important aspect of edge computing as it optimizes resource utilization while maintaining the requirements of low-latency applications, improved fault tolerance, energy efficiency, adaptability, scalability, …


Calibration And Validation Of The Thermal Finite Element Model For Er120s-G Wire Arc Directed Energy Deposition Using Infrared Cameras And Thermocouples, Joshua Mykl Bassett Aug 2025

Calibration And Validation Of The Thermal Finite Element Model For Er120s-G Wire Arc Directed Energy Deposition Using Infrared Cameras And Thermocouples, Joshua Mykl Bassett

Theses and Dissertations

Wire Arc Directed Energy Deposition (WA-DED) is a promising additive manufacturing method for producing large metallic components with high deposition rates and low costs. However, its rapid heat input can lead to residual stress, microstructural changes, and dimensional inaccuracies. Accurate thermal modeling is essential to mitigate these effects. This study presents a thermal calibration of a finite element model (FEM) for ER120S-G using thermocouples and infrared (IR) imaging. Thermal data were gathered from three experiments to complete the calibration of the FEM . Calibration focused on tuning the Goldak heat source parameters, power efficiency, and heat transfer coefficients to minimize …


Transforming Movement Assessment In Physical Therapy Through Subaquatic Data Collection, Kaitlyn Mcdonald Aug 2025

Transforming Movement Assessment In Physical Therapy Through Subaquatic Data Collection, Kaitlyn Mcdonald

Theses and Dissertations

This study explored the interest and perceived barriers to integrating subaquatic diagnostic technologies (SDTs) into hydrotherapy among licensed physical therapists. Seventeen semi-structured interviews were conducted using a mixed-methods design, with 15 interviews included in the final analysis. Quantitative data were analyzed using chi-square tests, while qualitative responses were coded thematically. Results indicated no statistically significant relationships between SDT interest and career stage or hydrotherapy access, though qualitative data highlighted concerns about cost, limited access, and usability. Despite mixed interest in adoption, participants identified several potential benefits of SDTs, including improved treatment tailoring, increased patient buy-in, and enhanced outcome monitoring. Functional …


Thermo-Mechanical Advancements For Very High Strength And Ultra High Performance Concretes, Lana Grayson Brown Sisung Aug 2025

Thermo-Mechanical Advancements For Very High Strength And Ultra High Performance Concretes, Lana Grayson Brown Sisung

Theses and Dissertations

Interest in the use of high-strength concrete (HSC) has increased in recent years with demand for improved concrete performance. HSCs are widely associated with high heat of hydration and elusive behavior when exposed to high temperatures commonly occurring in mass structures. The optimization of HSC mixture proportioning is difficult due to a wide variety of constituents that influence thermal and mechanical properties. Additionally, determining in-place properties of mass concrete placements is elusive, and there are currently minimal to no test methods available that are both predictive and a direct measurement of mechanical properties. The objective of this dissertation is to …


Non-Thermal Dbd Plasma-Induced Co₂ Capture And Conversion To Value Added Chemicals, Chinwendu Theresa Umeojiakor Aug 2025

Non-Thermal Dbd Plasma-Induced Co₂ Capture And Conversion To Value Added Chemicals, Chinwendu Theresa Umeojiakor

Theses and Dissertations

Electrified CO2 conversion via nonthermal dielectric-barrier discharge (DBD) plasma presents a promising pathway for integrating renewable energy into the carbon cycle, addressing the dual challenges of CO2 reduction and sustainable fuel generation. In this research, DBD plasma technology was integrated with a sorbent material and/or catalytic materials for CO2 desorption and conversion. Specifically, with Ni/Al2O3 as the catalyst, we investigated CO2 splitting (CO2 to CO and 0.5O2) and hydrogenation (CO2 and H2 to CO and H2O) under adiabatic and subcooled conditions. We find that CO2 splitting shows higher efficiency than hydrogenation, particularly at relatively lower power inputs. While CO2 hydrogenation …


Transformations Of Uzbekistan Quartz Raw Materials – Quartzites Of The Dzherdanak Deposit And Vein Quartz Of The Nurota Deposit Under Thermal Impact, Umar G. Nomazov, Mastura Kh. Aripova Aug 2025

Transformations Of Uzbekistan Quartz Raw Materials – Quartzites Of The Dzherdanak Deposit And Vein Quartz Of The Nurota Deposit Under Thermal Impact, Umar G. Nomazov, Mastura Kh. Aripova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work is to study the transformations of quartz raw materials as a result of high-temperature exposure. The objects of the study were quartzite from the Dzherdanak deposit in the Surkhandarya region and vein quartz from the Nurota deposit in the Samarkand region. The mineralogical composition of natural raw materials and phase and structural transformations during high-temperature exposure to 1430 ° C were studied using X-ray and differential thermal analysis. Based on the results of physicochemical analysis methods, it was found that vein quartz consists entirely of quartz and, therefore, it can be assumed that impurity elements …


Kinetics Of Adsorption Of Copper And Nickel Ions Using A Rice Husk-Based Sorbent, Aziza A. Maksudova, Shukhrat A. Mutalov, Klara M. Adilova Aug 2025

Kinetics Of Adsorption Of Copper And Nickel Ions Using A Rice Husk-Based Sorbent, Aziza A. Maksudova, Shukhrat A. Mutalov, Klara M. Adilova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study is to investigate the adsorption kinetics of Cu(II) and Ni(II) ions from aqueous solutions using an adsorbent obtained by treating rice husk with a solution of monoethanolamine. The experiments evaluated the influence of contact time on the efficiency of metal ion removal and calculated the adsorption capacity. To analyze the adsorption process kinetics, pseudo-first-order and pseudo-second-order kinetic models were applied. The results demonstrated that the adsorption process follows the pseudo-second-order kinetic model. Thus, monoethanolamine-modified rice husk can be considered an effective, environmentally friendly, and economically viable sorbent for the removal of heavy metal ions from …


Quantum-Chemical Study Of Complex Compounds Of Lanthanides With 2-Aminobenzimidazole Derivatives, Bakhtigul Yu. Ruzieva, Feruza F. Fayzullayeva, Zuhra Ch. Kadirova, Shahlo Sh. Daminova Aug 2025

Quantum-Chemical Study Of Complex Compounds Of Lanthanides With 2-Aminobenzimidazole Derivatives, Bakhtigul Yu. Ruzieva, Feruza F. Fayzullayeva, Zuhra Ch. Kadirova, Shahlo Sh. Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study is to perform quantum-chemical modeling of mixed-ligand complexes of trivalent lanthanoid ions (Ln³⁺) involving primary ligands — 2-amino-1-methylbenzimidazole (MAB) and 2-phenylmethyl-1H-benzimidazole (FAB), as well as additional ligands — diethyldithiocarbamate (DEDTK), benzohydroxamic acid (BGK), and potassium diisopropyldithiophosphate (DiPDTP). Quantum-chemical calculations were carried out using semi-empirical methods within the PM3 and PM6 approaches, implemented in the BIOVIA Materials Studio (Accelrys Studio 2017) software package. The obtained data made it possible to determine the influence of the nature of the mixed ligands on the coordination behavior of lanthanoids and the stability of the corresponding complexes.


Synthesis And Ir Spectroscopic Study Of Complexes Of Selected 3d-Metals With 2-(Phenylmethyl)-1h-Benzimidazole, Gulnoza O. Babayeva, Gulbeka G. Mamatova, Daminbek A. Ziyatov, Lola Sh. Makhmudova, Shahlo Sh. Daminova Aug 2025

Synthesis And Ir Spectroscopic Study Of Complexes Of Selected 3d-Metals With 2-(Phenylmethyl)-1h-Benzimidazole, Gulnoza O. Babayeva, Gulbeka G. Mamatova, Daminbek A. Ziyatov, Lola Sh. Makhmudova, Shahlo Sh. Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study was the synthesis and structural investigation of coordination compounds of selected 3d-metals with 2-(phenylmethyl)-1H-benzimidazole (FAB) using IR spectroscopy. Complexes of copper(II), nickel(II), cobalt(II), and zinc(II) with the general formula [M(FAB)2Cl2], as well as a complex [Co(FAB)2(ac)2], were synthesized. IR spectroscopic analysis revealed that FAB coordinates to metal ions through the nitrogen atom of the benzimidazole ring. Shifts in the ν(C=N), ν(C-N) bands and the appearance of new bands in the 580-430 cm⁻¹ region corresponding to ν(M-N) and ν(M-Cl) confirm the formation of metal complexes. It was established …