Materials Science and Engineering Commons^™

Microwave Synthesis Of Yttrium Oxide Nanostructure Powders, Doped With Ytterbium And Erbium Ions, Eygeniy N. Poddenezhny, Andrei A. Boiko, Olga V. Davydova, Ekaterina E. Trusova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study was to develop microwave synthesis of luminescent yttrium oxide powders doped with ytterbium and erbium ions (Y₂O₃:Yb³⁺_, Er³⁺) in the process of homogeneous precipitation from a reaction mixture of yttrium, ytterbium and erbium chlorides. The characteristics of the obtained powders were studied by X-ray diffraction, scanning and passing electron microscopy, differential thermal analysis, IR spectroscopy and photoluminescence under IR excitation. From luminescence spectra of Y₂O₃:Yb³⁺, Er³⁺ samples obtained by excitation with an IR laser at a wavelength of 975 nm, …

Optical Glass With Increased Refractive Index Based Bao – B2o3 – Sio2 System, Yury G. Pavliukevich, Ludmila F. Pаpko, Ekaterina E. Trusova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research is to develop lead-free optical glass with increased refractive index based on BaO – B₂O₃ – SiO₂ system. A study of technological and physical-chemical properties of glass was conducted. It has been shown that the glass of this system tends to the phase separation of segregation type. The area of glass composition with refractive index of 1.6195 – 1.6650 has been established. The peculiarities of influence of the modifiers – Al₂O₃ and oxides of the RO group – on the technological and optical properties of the glass of …

Tribocorrosion And Metal Release From Austenitic Stainless Steels 304 And 201 In Simulated Cassava Food Contact, Robert Addai, Temitope E. Olowoyo, Thalia E. Standish, Jeffrey Daniel Henderson, Ubong Eduok, Yolanda Hedberg

Chemistry Publications

Cassava is the third most significant calorie source in the tropics. Its processing has changed from traditional methods to stainless steel processing machines. This study investigated the influence of cassava on metal release from two common stainless steels, ASTM 304 and 201, with and without friction, and on tribocorrosion (multianalytically) of 304. Cassava was relatively corrosive and hindered repassivation of the surface oxide of stainless steel, but it also acted as a lubricant against mechanical friction. The combined action of friction and cassava caused a significant increase in iron, chromium, nickel, and manganese release from the stainless steels (30–35- fold …

Pulsing-Induced Healing Of A Surface Crack Of A Nickel-Based Alloy, Liwei Wang, Mingming Quan, Zhen Tan, Ming Liu, Dianlong Wang, Xiao Yang, Ying Liu, Yaning Mao, Zhimin Liang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this work, we demonstrate the feasibility of applying electric pulses to heal surface cracks on nickel-based alloy GH4169 under compressive load. There exists an incubation time for the onset of the healing of a crack, which is associated with local temperature at the crack tip. The crack size decreases with increasing the pulsing time at a constant healing rate prior to complete healing of the crack. Increasing compressive load accelerates the healing process. The electric pulsing leads to the formation of an influential zone surrounding the crack with the finest grain sizes in the healed crack and the coarsest …

Microstructural Evolution In A Precipitate-Hardened (Fe0.3ni0.3mn0.3cr0.1)94ti2al4 Multi-Principal Element Alloy During High-Pressure Torsion, Matthew Luebbe, Jiaqi Duan, Peipei Cao, Zhaoping Lu, Rinat K. Islamgaliev, Ruslan Z. Valiev, Yuzi Liu, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Multi-principal element alloys demonstrate high strength, thermal stability, and irradiation resistance, making them excellent candidate materials for applications in nuclear reactors and other harsh environments. Some studies have examined the use of high-pressure torsion to strengthen MPEAs through grain size reduction and strain hardening. However, no studies have investigated the effect of HPT on secondary phases (precipitates) within an MPEA. Two alloys, (Fe_0.3Ni_0.3Mn_0.3Cr_0.1)₉₄Ti₂Al₄ containing Ni(Ti, Al) B2 phase, and CrFe σ phase, and single-phase Fe_0.3Ni_0.3Mn_0.3Cr_0.1, were fabricated by casting …

Experimental Investigation Of The Self-Healing Potential Of Bacteria For Sustainable Concrete Structures Phase 2, Andrea Calabrese, Pitiporn Asvapathanagul, Nisarg N. Patel, Nanubala Dhruvan, Austin Adams, Michael Hernandez, Douglas S. Lopez-Cruz

Mineta Transportation Institute

Concrete is a critical component of so much of the modern construction industry. This material, well known for its versatility, robustness, longevity, and strength, is well-suited for a wide range of structural applications. Nonetheless, the widespread occurrence of cracks in concrete structures, primarily attributed to its limited tensile strength, shrinkage, and overstain, imposes a considerable economic and environmental challenge when it comes to retrofitting these fissures. This study tackles this problem by harnessing bacteria tolerant to high alkaline conditions to enable Microbially Induced Calcium Carbonate Precipitation (MICP) for the self-repair of concrete. This is achieved through an external application method, …

Poly(Thioether) Thermosets With Gated Photodegradation, Surabhi Jha

Dissertations

Photodegradable polymer networks are attractive due to the precise spatiotemporal control and large-area applicability of light. Chemical linkages that enable these polymer networks to be photo-responsive, also hinder their applicability in ambient light. Photostable and photodegradable networks have recently been reported to overcome this challenge by combining other stimuli with light for degradation. We report the design of a network that responds to a simultaneous, dual stimulus for photodegradation. We design poly(thioether acetal) networks with benzylidene acetal moieties that are known to undergo β-scission in the presence of free thiols. By blocking these free thiols with a thermally labile protecting …

Electrical And Morphological Investigation Of A Fe(Ii) Based Spin Crossover Complex And Its Composite, Rifat Mahbub

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Spin crossover (SCO) complexes have unique properties of switching their spin state upon perturbations like temperature, pressure, light, etc. Along with the spin state, different properties vary like structural, electrical, magnetic, optical properties. This enables these materials to be potentially used in various applications like molecular electronics, memory devices, switching devices, sensors and many more. To incorporate spin crossover materials into devices with efficient performance, the electrical behavior needs to be understood. This dissertation aims to investigate the effect of crystal structure on the electrical properties of iron(II) triazole spin crossover complex and how it can be modified for better …

Understanding And Tuning Magnetism In Layered Ising-Type Antiferromagnet Fepse3 For Potential 2d Magnet, Rabindra Basnet, Taksh Patel, Jian Wang, Dinesh Upreti, Santosh Karki Chhetri, Gokul Acharya, Md Rafique Un Nabi, Joshua Sakon, Jin Hu

Chemistry & Biochemistry Faculty Publications and Presentations

Recent developments in 2D magnetic materials have motivated the search for new van der Waals magnetic materials, especially Ising-type magnets with strong magnetic anisotropy. Fe-based MPX₃ (M = transition metal, X = chalcogen) compounds such as FePS₃ and FePSe₃ both exhibit an Ising-type magnetic order, but FePSe₃ receives much less attention compared to FePS₃. This work focuses on establishing the strategy to engineer magnetic anisotropy and exchange interactions in this less-explored compound. Through chalcogen and metal substitutions, the magnetic anisotropy is found to be immune against S substitution for Se whereas …

Growth And Simulation Of Dielectric-Metal Nanoheterostructured Thin Films By Ballistic Deposition, Shawn Wimer

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This thesis is divided into two related topics: the structural and chemical characterization of dielectric-metal nanoheterostructured thin films grown by glancing angle deposition (GLAD) and the results of the simulated growth of films and structures by GLAD with discrete-space and continuous-space Monte Carlo ballistic simulation.

Individual structures comprising films grown by GLAD were investigated by S/TEM and SEM imaging, electron diffraction, and chemical characterization and mapping by EDX. Different intermolecular interactions within and between different materials, including Si, Ag, Au, and ZrO₂, are linked to differences in the shapes of individual materials in heterostructures, the shape of heterostructures …

Laser 3d Printing Of Diamond-Based Composite Materials For Thermal Management Applications, Nada Kraiem

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

With the trend towards miniaturization of electrical equipment and the constant increase in power density in semiconductor devices, efficient heat management has become a major concern for researchers. Indeed, this technological evolution imposes increasingly strict constraints in terms of thermal dissipation, necessitating innovative solutions to ensure better durability and reliability of components. In this context, the use of composite materials offering high thermal conductivity (TC) and low coefficient of thermal expansion (CTE) compared to pure metals has become essential to address overheating issues in electronic components.

The utilization of advanced materials such as diamond (D), with exceptional TC and hardness …

Advancements In Microscale Tensile Testing: A Novel Device For The High Throughput Analysis Of Two-Photon Polymerized Microfibers In Liquid, Grayson D. Minnick

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Two-photon polymerization (TPP) enables the 3D fabrication of micro- and nanostructures from biocompatible materials with high resolutions, reaching into the realm of hundreds of nanometers. Such capabilities are crucial for advancing applications in fields like mechanobiology. As microscale technologies evolve, the precise characterization of material properties becomes increasingly essential. This is especially true for TPP-printed microstructures serving as scaffolds for 3D cell culture and intended for studying the mechanics of tissues. Despite the importance, traditional micro-scale tensile testing methods typically lack scalability and fail to replicate relevant environmental conditions. This dissertation introduces a new device that is specifically designed to …

Dual Light Emission Of Cssni3-Based Powders Synthesized Via A Mechanochemical Process, Xuan Huang, Xiaobing Tang, Xiyu Wen, Yuebin Charles Lu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Lead toxicity has hindered the wide applications of lead halide perovskites in optoelec- tronics and bioimaging. A significant amount of effort has been made to synthesize lead-free halide perovskites as alternatives to lead halide perovskites. In this work, we demonstrate the feasibility of synthesizing CsSnI3-based powders mechanochemically with dual light emissions under ambi- ent conditions from CsI and SnI2 powders. The formed CsSnI3-based powders are divided into CsSnI3-dominated powders and CsSnI3-contained powders. Under the excitation of ultraviolet light of 365 nm in wavelength, the CsSnI3-dominated powders emit green light with a wavelength centered at 540 nm, and the CsSnI3-contained powders …

Carbon-Based Nanocomposite Membranes For Membrane Distillation: Progress, Problems And Future Prospects, Chhabilal Regmi, Yuwaraj K. Kshetri, S. Ranil Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

The development of an ideal membrane for membrane distillation (MD) is of the utmost importance. Enhancing the efficiency of MD by adding nanoparticles to or onto a membrane’s surface has drawn considerable attention from the scientific community. It is crucial to thoroughly examine state-of-the-art nanomaterials-enabled MD membranes with desirable properties, as they greatly enhance the efficiency and reliability of the MD process. This, in turn, opens up opportunities for achieving a sustainable water–energy–environment nexus. By introducing carbon-based nanomaterials into the membrane’s structure, the membrane gains excellent separation abilities, resistance to various feed waters, and a longer lifespan. Additionally, the use …

Enhancement Of Polytetrafluoroethylene-Polyvinyl Alcohol Nanofibers Triboelectric Effect With Carboxylic Functionalized Multiwalled Carbon Nanotubes Coating, Fernando Viesca

Theses and Dissertations

In this study, we fabricated a TENG using Forcespinning® (FS) Polytetrafluoroethylene microfibers (FS-PTFE-MFs) and Electrospun (ES) Polyvinyl alcohol nanofibers (ES-PVA-NFs). The FS-PTFE-MFs were physically linked with functionalized carboxylic multiwall carbon nanotubes (MWCNTs-COOH) employing water dispersions. MWCNTs-COOH were dispersed using three different surfactants: Sodium Dodecyl Sulfate (SDS), Sodium dodecylbenzenesulfonate (SDBS), and Triton X-100 (TX-100). Coated FS-PTFE-MFs were then characterized using a field emission scanning electron microscope (FESEM) with an energy dispersive X-ray spectroscopy (EDS) attachment and Fourier-transform infrared spectroscopy (FTIR). While no significant difference in performance was observed with different surfactants, electrical results of the TENG recorded a notable enhancement of …

Performance Evaluation Of Asphalt Binder Modified With Recycled Plastics, Abeeb G. Oyelere

Graduate Theses and Dissertations (2019 - present)

The surge in the production of plastic waste has become a pressing global environmental issue. To address this, repurposing plastic waste to modify asphalt binders in asphalt pavement is being explored This study investigates the potential of recycled high-density polyethylene (rHDPE) and recycled polypropylene (rPP) as asphalt binder modifies to improve pavement performance and sustainability while mitigating plastic waste's adverse environmental impacts. Laboratory investigations were conducted to assess the rheological performances as well as the compatibility of rHDPE and rPP-modified asphalt. Additionally, the impact of aging and mixing temperature on rheological performance was investigated. Experimental results indicated that adding these …

Mesostructure Reconstruction Of Prepreg Platelet Molded Composite With Artificial Intelligence, Richard Larson

Mechanical & Aerospace Engineering Theses & Dissertations

Prepreg platelet molded composites (PPMC) are long, discontinuous fiber reinforced polymer materials. PPMC are an important subcategory of composite materials as they are processible into geometrically complex structures and can be produced via high-throughput manufacturing processes, however they have higher stiffness and strength as compared to traditional discontinuous fiber reinforced polymers. However, there is inherent randomness in the structure of PPMCs and as such, PPMC parts frequently require per part testing that is cost prohibitive.

Herein, a method using artificial intelligence is proposed as a more cost-effective method of inspecting PPMC parts. Different artificial intelligence (AI) architectures are explored to …

Alternative Applications Of Composite Materials To Reduce Radar Cross Section, Mark Patterson

Mechanical & Aerospace Engineering Theses & Dissertations

The use of carbon nanoparticles and graphene in composite materials has created a foundational shift in enhancing performance across mechanical, thermal, and electrical properties. Such applications are vital in the aerospace industry. However, there has not been such a focus on the material use for reducing radar cross section (RCS). Historically, RCS is minimized by designing sharp geometric shapes to deflect or dissipate the incoming electromagnetic waves away from the receiving antenna. However, these designs are not always optimized for aerodynamics. The goal of this research is to understand the application of composite materials and specifically carbon nanotubes (CNTs) to …

Process Modeling Of Composites For Automated Fiber Placement, Von Clyde Jamora

Mechanical & Aerospace Engineering Theses & Dissertations

Fiber-reinforced composites are available in various material systems, each requiring specific manufacturing techniques to exploit their unique properties fully. Systems such as woven fabrics and preimpregnated fibers employ distinctive methods to harness these properties effectively. For instance, non-crimp fabrics (NCF) use high-pressure resin transfer molding and prepregs, like IM7-8552, use manufacturing method called automated fiber placement (AFP). However, these manufacturing processes often introduce deposition features that can evolve into defects. Their occurrence and impact on morphology must be predicted using experimentally informed finite element models. The research began with compaction experiments on NCF fabric, leading to the development of a …

An In – Depth Analysis Of Natural Fibers :A Comprehensive Review Of Properties And Performance Characteristics, Abbas Chour, Jamal Khatib

BAU Journal - Science and Technology

The purpose of this research is to investigate the usage of natural fibers in plant-based natural fiber-reinforced cement-based composites for sustainable construction materials. It summarizes research on various fiber kinds, their properties, and their impact on cement-based products, with a focus on renewable possibilities such as flax, jute, ramie, hemp, cotton, sisal, and kenaf. Due to their hydrophilic nature, plant fibers and polymers present compatibility concerns and moisture damage when combined. The paper examines ways for improving durability, such as physical and chemical treatments to improve aging resistance, optimizing binder components, and modifying curing regimens to reduce alkalinity in the …

Optimizing The Expression Of Polyethylene Terephtalate Hydrolase-Encoding Synthetic Gene In Escherichia Coli Arctic Express (De3), Jocelyn Nataniel, Maria Ulfah, Dini Achnafani, Niknik Nurhayati, Gabriela Christy Sabbathini, Sri Rezeki Wulandari, Abinawanto Abinawanto, Is Helianti

Makara Journal of Science

The waste of polyethylene terephthalate (PET) plastic waste in Indonesia is a pressing concern due to its slow degradation and potential environmental damage. One promising solution is to utilize polyethylene terephthalate hydrolase from Ideonella sakaiensis (IsPETase), an enzyme that specifically degrades PET. However, inducing the expression of IsPETase synthetic gene in Escherichia coli BL21 (DE3) has been challenging because much of it remains insoluble. This study aimed to express IsPETase in E. coli Arctic Express (DE3) and optimize the conditions to enhance its production. First, pET22b(+)pelB-IsPETase was inserted into E. coli Arctic Express (DE3). The …

Preparation Of Β-Ni (Oh)2 Nanosheet–Modified Glassy Carbon For Pseudocapacitors, Muhammad Buchari Setia Putra, Aliyah Aliyah, Afiten Rahmin Sanjaya, Respati Kevin Pramadewandaru, Hoeil Chung, Tribidasari Anggraningrum Ivandini

Makara Journal of Science

β-Nickel hydroxide (Ni(OH)₂) nanosheet–modified glassy carbon for pseudocapacitors was successfully prepared. The nanosheets were synthesized via a conventional growth seeding method combined with hydrothermal treatment. Transmission electron microscopy (TEM) characterization indicated the hexagonal structure of the nanosheets of around 15 nm in size, and X-ray diffraction (XRD) pattern confirmed the β-phase lattice crystal. These nanosheets used to modify the glassy carbon surface, increased the electroactive surface area by around 15 times. Furthermore, electrochemical investigation of the modified glassy carbon revealed an excellent performance and a specific capacitance of 628.01 F g⁻¹ at a 1 A g^{−1 …}

Repair And Surface Functionalization Of Fiber Reinforced Polymer Composites By Cold Spray, Ibnaj Anamika Anni

Theses and Dissertations

Fiber-reinforced polymer composites are widely used in industries and applications such as energy, automotive, defense, and aerospace. This study investigates the application of polymer cold spray, an emerging additive manufacturing process, for coating and repair of fiber-reinforced polymer (FRP) composites. The research starts with feasibility studies focused on the cold spray deposition of thermoplastic nylon-6 particles on woven glass fiber-reinforced composites (GFRP). A parametric study determines critical process parameters window, ensuring successful deposition and bonding without compromising the macroscale mechanical behavior. These findings indicate that the cold spray process does not adversely affect the fiber integrity or surface quality of …

Surface Structures And Properties Of High-Voltage Licoo2: Reviews And Prospects, Jian-Jun Fang, Yu-Hao Du, Zi-Jian Li, Wen-Guang Fan, Heng-Yu Ren, Hao-Cong Yi, Qing-He Zhao, Feng Pan

Journal of Electrochemistry

Nowadays, the development of high-voltage LiCoO₂ (lithium cobalt oxide, LCO) cathodes has attracted the widespread attention from both the academic and industry fields. Among the multiple concerns, researches on the surface issues would provide the most effective performance optimization pathway for the synthesis of high-voltage LCO. In this work, the issues of high-voltage LCO, including the phase transitions and crack formation, the oxygen redox related issues and side reactions, as well as the surface structure degradation, have been systematically reviewed. Then, we further clarify the surface modulations, and the interplay between the surface modulation and electrolyte tuning. Finally, we …

In Situ Diffuse Reflectance Spectroelectrochemistry Of Cathode Materials In Lithium-Ion Batteries, Lu-Lu Chen, Hao-Ran Li, Wei-Yi Liu, Wei Wang

Journal of Electrochemistry

Developing in situ spectroelectrochemistry methods, which can provide detailed information about species transformation during electrochemical reactions, is very important for studying electrode reaction mechanisms and improving battery performance. Studying real-time changes in the surface of electrode materials during normal operation can be an effective way to assess and optimize the practical performance of electrode materials, thus, in situ and in operando characterization techniques are particularly important. However, batteries are hard to be studied by in situ characterization measurements due to their hermetically sealed shells, and there is still much room for battery characterizations. In this work, a specially designed battery …

Molybdenum Disulfide And Carbon Nanotubes Composite Electrode For Electrochemical Conversion Of Salinity Gradient Energy, Jia-Jun Li, Wei-Bin Zhang, Xin-Yu Liu, Jing-Lei Yang, Yi Yin, Ze-Qin Yang, Xue-Jing Ma

Journal of Electrochemistry

The ocean accounts for 97% of the total water resources on earth, covering over 70% of the map's surface area. With the continuous consumption of non-renewable energy sources such as fossil fuels and the rapid development of renewable energy, humans are increasingly paying attention to the utilization of ocean resources. Ocean energy includes tidal energy, wave energy, temperature difference energy, and salinity gradient energy. Salinity gradient energy is the energy generated by the interaction of seawater and fresh water, which is the ocean energy existing in the form of chemical energy. This energy is mostly generated in estuaries. The osmotic …

Effect Of Hydrothermal Coupling Aging On Performance Of Rubber Modified Asphalt, Chen Zhenwei, Wu Xuewen, Xiao Xuan, Li Ping, Liu Shende

Journal of China & Foreign Highway

To study the effect of hydrothermal coupling aging on the performance of rubber modified asphalt,this article simulated thermal aging and hydrothermal coupling aging tests and investigated the effect of different aging environments on the high-temperature and low-temperature performance of asphalt from macroscopic and microscopic levels through conventional index tests,dynamic shear rheology tests,and gel chromatography tests,as well as the effect of different aging environments on the interfacial properties through low-temperature adhesion tests of asphalt and aggregates.The results show that the effects of hydrothermal coupling aging on the ductility and softening point of rubber modified asphalt are more significant than those of …

Fatigue Performance Of Qingchuan Rock Modified Asphalt Mixture Under Accelerated Loading Test, Li Zhi, Hao Yan, Yuan Xiaoman, Zhuang Chuanyi

Journal of China & Foreign Highway

To evaluate the fatigue performance of Qingchuan rock modified asphalt mixture,a dynamic wheel-load three-point bending loading fatigue test device based on an accelerated loading test system of 1∶3 scale pavement was designed.The three-point bending repeated loading fatigue test of a composite rutting specimen of double-layer asphalt mixture under tire rolling was carried out.Through the MTS bending fatigue test of a small beam specimen of asphalt mixture,the improvement effects of Qingchuan rock modified asphalt and composite modified asphalt on the fatigue performance of the asphalt mixture were evaluated.The results show that Qingchuan rock modified asphalt can improve the ability of asphalt …

Analytical Method For Deformation And Internal Force Of Suspension Bridge Under Concentrated Live Load, Zhao Haixia, Wang Tao

Journal of China & Foreign Highway

As a flexible structure,the response of suspension bridges under live load has been the focus of research for a long time.This paper presented an analytical calculation method for structural deformation and internal force of suspension bridges under concentrated live load.Based on the known bridge state parameters and live load parameters,the deformation of the main cable,the deformation of the main beam,the relationship between the main cable and the main beam,and the deformation of the bridge tower were analyzed successively.Then,four kinds of governing equations were established,involving the conserved unstrained length of each main cable,the coordinated force and deformation of each suspender,the closed …

Influence Of Crosswind On Traffic Operation Safety Of Long‑Span Bridges, Shen Quanjun, Wang Zijian, Xing Xiaoliang, Zhang Yu, Gao Lixiao, Chen Liang

Journal of China & Foreign Highway

Crosswind has a great influen ce on the operation safety of vehicles on long-span bridges.To explore the relationship between the characteristic parameters of the crosswind and the traffic operation safety of the long-span bridge,the Yellow River Bridge with frequent crosswinds was taken as the experimental section,and the relationship between traffic accidents and the distribution of crosswinds on the bridge was analyzed.A fitting relationship model of traffic operation coordination of the long-span bridge under the action of the crosswind was established.The study shows that the occurrence of crosswinds in each season is highly discrete.The crosswind is the main cause of vehicle …