Materials Science and Engineering Commons^™

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 …

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 …

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 …

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 …

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 …

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 …

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 …}

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 …

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 …

Ultrasound Based Dynamic Reference Reflection Technique For Simultaneous Specific Gravity And Temperature Estimation, Jose Paul

USF Tampa Graduate Theses and Dissertations

This work is driven by the need for a noninvasive density estimation device for pipeline infrastructure due to the increased risk of volatility in the high energy density fuels that are available in the market. Ultrasound based techniques have proved to be a viable alternative to traditional u tube resonance or nuclear techniques due to their robustness and safety offering. The major update that this work intends to make to the existing technology is development of a system wherein the transducer or the electronic components remain isolated from the flow field.As a result, this work dives headfirst into the fundamentals …

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 …

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 …

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 …

Pollution Characteristics Of Heavy Metals In Solid Waste Subgrade Filling Materials, Du Qianhui, Fu Wei, Zhang Junhui, Tang Qiang, Gu Fan

Journal of China & Foreign Highway

Using solid waste in the road engineering field for subgrade filling is an important approach for building green and low-carbon emission roads.However,most solid waste contains heavy metal pollutants to varying degrees,and heavy metals will be released under complex environments including rainfall infiltration and groundwater immersion,thereby causing pollution to the surrounding soil and groundwater if not handled properly.This paper reviewed the current status of research on four aspects,including the comprehensive use of solid waste materials in subgrade engineering,the leaching and migration behaviors of heavy metals in solid waste,and the prevention and control treatment of heavy metals in solid waste.It is found …

Experimental Study On Influence Of Adsorbed Bound Water On Strength And Permeability Characteristics Of High Liquid Limit Soil, Fu Ceyuan, Zhou Shijie

Journal of China & Foreign Highway

In order to reveal the influence of adsorbed bound water on the strength and permeability characteristics of high liquid limit soil,the initial adsorbed bound water content of the high liquid limit soil specimens from Hunan and Hainan was controlled by different concentrations of sodium chloride solution,and thermogravimetric analysis method was used to determine the content.The direct shear test,unconfined compressive strength test,and permeability test were carried out.The results show that the adsorbed bound water content decreases with the increase in salt solution concentration,while the strong bound water content is basically unchanged.The adsorbed bound water has a high viscosity,low activity,and certain solid-like …

Analysis Of Asphalt Pavement Structure Based On Master Curve Parameters Of Dynamic Modulus Of Asphalt Mixture, Liu Zhaohui, Yang Xin, Huang You, Liu Li

Journal of China & Foreign Highway

In order to study the effect of the change in the master curve parameters of the dynamic modulus of asphalt mixture and the interaction on the structural response of asphalt pavement,a three-dimensional model of the asphalt pavement structure was established using the finite element method,and the structural calculations of asphalt pavement with semi-rigid base and flexible base were carried out.The master curve parameters of the dynamic modulus δ,α,β,and γ were taken as the influencing factors,and the maximum tensile strain at the bottom of the asphalt layer and the vertical compressive strain at the top of the subgrade were set as …

Mechanism Of Water‑Damaged Landslides Of Embankments And Comparison Of Reinforcement Measures, Hu Minghua, Zhang Baiyong, Xu Kui

Journal of China & Foreign Highway

Water damage to embankments serious ly affects the normal operation of highways,so it is extremely important to ensure the stability of the embankment.In addition,it is necessary to analyze the mechanism and study the safety control measures for water-damaged landslides of the embankment.A highway subgrade embankment was studied,and the causes and formation mechanism of the landslide were qualitatively analyzed based on the on-site deformation monitoring and stability calculation.Then,the stability coefficients of different reinforcement schemes were calculated.An appropriate reinforcement scheme was recommended by considering the project cost,construction technology,and construction period.The results indicate that uneven settlement of the embankment stratum is the fundamental …

Effect Of Cellulose Fiber On Humidity Control And Properties Of Cement Mortar, Liang Jinguo, Ma Baofu

Journal of China & Foreign Highway

To explore the effect of flax cell ulose fiber on the humidity and basic properties of cement mortar,this paper adopted flax cellulose fibers with different lengths (0.5 and 5 mm ) and mixing amounts (mass fraction of 0.5%,1%,1.5%,and 2% of cement ).Tests were conducted on rheological properties,mechanical properties,autogenous shrinkage properties,and internal relative humidity development of cement mortar.Setting time,compressive strength,shrinkage rate,and relative humidity were used to evaluate the performance improvement effect of cellulose fiber on cement mortar.The results show that the absorbance rate of flax fiber per unit mass of 0.5 mm is 3.45 times its weight,while the absorbance rate of …

Micro Mechanical Analysis And Experiment On Fatigue Damage Of Rubber Powder Asphalt Mixture Of Expressway, Li Nanpeng, Wang Guoqing, Wang Zhibin, Zhang Xia3, Si Chundi

Journal of China & Foreign Highway

To explore the fatigue damage mechanism and micro-mechanical behavior of the pavement of rubber powder asphalt mixture (ARHM- 20) of expressway influenced by heavy vehicles,a three-dimensional microstructural model of the mixture was built based on the discrete element method,and research on the damage mechanism from aggregate motion to macroscopic permanent deformation were conducted.The Burger's constitutive model was used to characterize the viscoelastic properties of asphalt mortar.The macro mechanical parameters of Burger ’s model at different temperatures were obtained through asphalt creep tests,and the micro modeling parameters were obtained based on the macro and micro conversion formulas.The irregular coarse aggregate was …

Meso-Mechanical Properties Of Bearing Ratio Of Waste Lime‑Fly Ash Macadam And Soil Mixture Based On Discrete Element, Zhang Xiaofei, Chen Yuru, Zhang Song, Gao Lei, Tian Angran, Tang Qiang

Journal of China & Foreign Highway

In the process of applying construction waste to subgrade,the bearing capacity of the material has an important impact on the service performance of roads.In order to evaluate the meso-mechanical properties of construction waste used as subgrade filler,the bearing ratio test of waste lime-fly ash macadam and soil mixture with different stone contents was carried out by using discrete element software.The strength formation mechanism was revealed by using the discrete element method.The results show that the bearing ratio of the mixture increases with the increase in the stone content and reaches the maximum value when the stone content is 80%.In the …