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2022

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Articles 181 - 210 of 335

Full-Text Articles in Engineering Science and Materials

From 2d Images To 3d Virtual Reality: A Digital Application In Cultural Heritage, Garrett Ronny Hucks Apr 2022

From 2d Images To 3d Virtual Reality: A Digital Application In Cultural Heritage, Garrett Ronny Hucks

Undergraduate Research Competition

The digital documentation and preservation of historic and cultural sites are urgent needs for local governments due to concerns regarding structural damage and deterioration over the long term. With new technologies like augmented reality (AR), virtual reality (VR), and mixed reality (MxR), enabling 3D, immersive, virtual experiences become feasible. In this poster presentation, we outline a novel methodology that allows site owners to capture, digitally preserve, and then view these historic sites in the virtual environment. To this end, 2D photographs of a historic site are first taken and then generated into a 3D point cloud in Agisoft. Thereafter, we …

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Method Of Embedded Imperfections For The Direct Simulation Of Deformation Instabilities In Film-Substrate Structures, Siavash Nikravesh Kazeroni Apr 2022

Method Of Embedded Imperfections For The Direct Simulation Of Deformation Instabilities In Film-Substrate Structures, Siavash Nikravesh Kazeroni

Mechanical Engineering ETDs

In this dissertation, a novel finite-element methodology called “embedded imperfections” is proposed and employed for computationally simulating various types of deformation instabilities observed in film-substrate structures subjected to mechanical loading. The approach involves the incorporation of elements having distinctive material properties within the film-substrate interface. One can interpret this practice as a deliberate distribution of material defects within the numerical model. It has been shown that embedded imperfections not only can trigger the onset of instability, but also can lead to “direct” simulation of deformation instability problems in that primary and subsequent instability modes can all be captured in a …

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Machine Learning Assisted Discovery Of Shape Memory Polymers And Their Thermomechanical Modeling, Cheng Yan Apr 2022

Machine Learning Assisted Discovery Of Shape Memory Polymers And Their Thermomechanical Modeling, Cheng Yan

LSU Doctoral Dissertations

As a new class of smart materials, shape memory polymer (SMP) is gaining great attention in both academia and industry. One challenge is that the chemical space is huge, while the human intelligence is limited, so that discovery of new SMPs becomes more and more difficult. In this dissertation, by adopting a series of machine learning (ML) methods, two frameworks are established for discovering new thermoset shape memory polymers (TSMPs). Specifically, one of them is performed by a combination of four methods, i.e., the most recently proposed linear notation BigSMILES, supplementing existing dataset by reasonable approximation, a mixed dimension (1D …

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Investigating The Possibility Of Using Smelted Water-Cooled Copper Slag Regolith As A Terrestrial Based Lunar Regolith Simulant, Scott A. Morley Apr 2022

Investigating The Possibility Of Using Smelted Water-Cooled Copper Slag Regolith As A Terrestrial Based Lunar Regolith Simulant, Scott A. Morley

Graduate Theses & Non-Theses

There is a need for a stable, efficient, and cost-effective option of a terrestrial lunar regolith simulant that can be easily made and at a lower cost to the consumer. A lunar regolith is the layer of unconsolidated rocky material covering bedrock that is on planets. All simulants fabricated for the moon, are based off three types of lunar regolith areas. The first is the lunar highlands which are the high areas of the moon, these areas are anthracitic. The second is lunar mare which is the meteoroid bombarded areas of the moon that look like dark grey areas from …

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Treatment Of Mine Tailings Through Two Methods Of Calcite Precipitation: (I) Using Natural Mineral Trona, (Ii) Microbially Induced Calcite Precipitation Via Denitrification, Nathaniel Small Apr 2022

Treatment Of Mine Tailings Through Two Methods Of Calcite Precipitation: (I) Using Natural Mineral Trona, (Ii) Microbially Induced Calcite Precipitation Via Denitrification, Nathaniel Small

Graduate Theses & Non-Theses

Mine tailings not only pose environmental risks such as dust emission and acid mine drainage but also present geotechnical risks in cases of tailings dam failures which could lead to loss of human life and severe damages to infrastructure. In-situ cementation of tailings has the potential to reduce the risks associated with such failures as well as the related environmental problems. Over the years, different methods of chemically and microbially induced cementation of tailings have been examined many of which have shown promising results on a laboratory scale and some even on a ϐield scale. In this paper, a new …

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Me-Em Enewsbrief, March 2022, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Apr 2022

Me-Em Enewsbrief, March 2022, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

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Ultra-Broadband And Polarization-Insensitive Metasurface Absorber With Behavior Prediction Using Machine Learning, Shobhit K. Patel, Juveriya Parmar, Vijay Katkar, Fahad Ahmed Al-Zahrani, Kawsar Ahmed Mar 2022

Ultra-Broadband And Polarization-Insensitive Metasurface Absorber With Behavior Prediction Using Machine Learning, Shobhit K. Patel, Juveriya Parmar, Vijay Katkar, Fahad Ahmed Al-Zahrani, Kawsar Ahmed

Department of Mechanical and Materials Engineering: Faculty Publications

The solar spectrum energy absorption is very important for designing any solar absorber. The need for absorbing visible, infrared, and ultraviolet regions is increasing as most of the absorbers absorb visible regions. We propose a metasurface solar absorber based on Ge2Sb2Te5 (GST) substrate which increases the absorption in visible, infrared and ultraviolet regions. GST is a phase-changing material having two different phases amorphous (aGST) and crystalline (cGST). The absorber is also analyzed using machine learning algorithm to predict the absorption values for different wavelengths. The solar absorber is showing an ultra-broadband response covering a 0.2–1.5 …

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Method Of Making Hinged Self-Referencing Fabry–Pérot Cavity Sensors, Jeremiah C. Williams, Hengky Chandrahalim Mar 2022

Method Of Making Hinged Self-Referencing Fabry–Pérot Cavity Sensors, Jeremiah C. Williams, Hengky Chandrahalim

AFIT Patents

A method is provided for fabricating a passive optical sensor on a tip of an optical fiber. The method includes perpendicularly cleaving a tip of an optical fiber and mounting the tip of the optical fiber in a specimen holder of a photosensitive polymer three-dimensional micromachining machine. The method includes forming a three-dimensional microscopic optical structure within the photosensitive polymer that comprises a two cavity Fabry-Perot Interferometer (FPI) having a hinged optical layer that is pivotally coupled to a suspended structure. The method includes removing an uncured portion of the photosensitive polymer using a solvent. The method includes depositing a …

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In Situ Characterization Of Electrode Structure And Catalytic Processes In The Electrocatalytic Oxygen Reduction Reaction, Ya-Chen Feng, Xiang Wang, Yu-Qi Wang, Hui-Juan Yan, Dong Wang Mar 2022

In Situ Characterization Of Electrode Structure And Catalytic Processes In The Electrocatalytic Oxygen Reduction Reaction, Ya-Chen Feng, Xiang Wang, Yu-Qi Wang, Hui-Juan Yan, Dong Wang

Journal of Electrochemistry

As an electrochemical energy conversion system, fuel cell has the advantages of high energy conversion efficiency and high cleanliness. Oxygen reduction reaction (ORR), as an important cathode reaction in fuel cells, has received extensive attention. At present, the electrocatalysts are still one of the key materials restricting the further commercialization of fuel cells. The fundamental understanding on the catalytic mechanism of ORR is conducive to the development of electrocatalysts with the enhanced activity and high selectivity. This review aims to summarize the in situ characterization techniques used to study ORR. From this perspective, we first briefly introduce the advantages of …

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In-Situ/Operando57Fe Mössbauer Spectroscopic Technique And Its Applications In Nife-Based Electrocatalysts For Oxygen Evolution Reaction, Jafar Hussain Shah, Qi-Xian Xie, Zhi-Chong Kuang, Ri-Le Ge, Wen-Hui Zhou, Duo-Rong Liu, Alexandre I. Rykov, Xu-Ning Li, Jing-Shan Luo, Jun-Hu Wang Mar 2022

In-Situ/Operando57Fe Mössbauer Spectroscopic Technique And Its Applications In Nife-Based Electrocatalysts For Oxygen Evolution Reaction, Jafar Hussain Shah, Qi-Xian Xie, Zhi-Chong Kuang, Ri-Le Ge, Wen-Hui Zhou, Duo-Rong Liu, Alexandre I. Rykov, Xu-Ning Li, Jing-Shan Luo, Jun-Hu Wang

Journal of Electrochemistry

The development of highly efficient and cost-effective electrocatalysts for the sluggish oxygen evolution reaction (OER) remains a significant barrier to establish effective utilization of renewable energy storage systems and water splitting to produce clean fuel. The current status of the research in developing OER catalysts shows that NiFe-based oxygen evolution catalysts (OECs) have been proven as excellent and remarkable candidates for this purpose. But it is critically important to understand the factors that influence their activity and underlying mechanism for the development of state-of-the-art OER catalysts. Therefore, the development of in-situ/operando characterizations is urgently required to detect key intermediates along …

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An Additive Incorporated Non-Nucleophilic Electrolyte For Stable Magnesium Ion Batteries, Mao-Ling Xie, Jun Wang, Chen-Ji Hu, Lei Zheng, Hua-Bin Kong, Yan-Bin Shen, Hong-Wei Chen, Li-Wei Chen Mar 2022

An Additive Incorporated Non-Nucleophilic Electrolyte For Stable Magnesium Ion Batteries, Mao-Ling Xie, Jun Wang, Chen-Ji Hu, Lei Zheng, Hua-Bin Kong, Yan-Bin Shen, Hong-Wei Chen, Li-Wei Chen

Journal of Electrochemistry

Non-nucleophilic electrolytes are promising next-generation highly stable electrolytes for magnesium-ion batteries (MIBs). However, a passivation layer on Mg metal anode usually blocks Mg2+ diffusion, leading to poor reaction kinetics and low Coulombic efficiency of the Mg plating/stripping in these electrolytes. Here we explore the utilization of phenyl disulfide (PDF) as a film-forming additive for non-nucleophilic electrolytes to regulate the interfacial chemistry on Mg metal anode. Phenyl-thiolate generated from the PDF additive was found to suppress the unfavorable surface blocking layer, resulted in a high Coulombic efficiency of up to 99.5% for the Mg plating/stripping process as well as a …

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Synchrotron X-Rays Characterizations Of Metal-Air Batteries, Ya-Jie Song, Xue Sun, Li-Ping Ren, Lei Zhao, Fan-Peng Kong, Jia-Jun Wang Mar 2022

Synchrotron X-Rays Characterizations Of Metal-Air Batteries, Ya-Jie Song, Xue Sun, Li-Ping Ren, Lei Zhao, Fan-Peng Kong, Jia-Jun Wang

Journal of Electrochemistry

The rapid development of electric vehicles urgently requires high-energy-density batteries. Recently, metal-air batteries have attracted much attention in industry and academia for their ultra-high theoretical energy densities. However, the practical application of metal-air batteries is severely impeded by multiple drawbacks, including severe side reactions, low energy efficiency, and limited cycle life. Understanding the reaction mechanism of the cell and further developing effective strategies are beneficial for the practical application of metal-air batteries. In the past decade, advanced characterization techniques have accelerated the development of metal-air batteries. In particular, synchrotron radiation-based characterization techniques have been widely applied to the mechanistic study …

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Closed-Loop Control Of Meltpool Temperature In Directed Energy Deposition, Ziyad M. Smoqi, Ben Bevans, Aniruddha Gaikwad, James Craig, Alan Abul-Haj, Brent Roeder, Bill Macy, Jeffrey E. Shield, Prahalada K. Rao Mar 2022

Closed-Loop Control Of Meltpool Temperature In Directed Energy Deposition, Ziyad M. Smoqi, Ben Bevans, Aniruddha Gaikwad, James Craig, Alan Abul-Haj, Brent Roeder, Bill Macy, Jeffrey E. Shield, Prahalada K. Rao

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this work is to mitigate flaw formation in powder and laser-based directed energy deposition (DED) additive manufacturing process through close-loop control of the meltpool temperature. In this work, the meltpool temperature was controlled by modulating the laser power based on feedback signals from a coaxial two-wavelength imaging pyrometer. The utility of closed-loop control in DED is demonstrated in the context of practically inspired trapezoid-shaped stainlesssteel parts (SS 316L). We demonstrate that parts built under closed-loop control have reduced variation in porosity and uniform microstructure compared to parts built under open-loop conditions. For example, post-process characterization showed that …

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Design And Testing Of A Composite Compressor Rotor, Mauro Noel V. De Leon Mar 2022

Design And Testing Of A Composite Compressor Rotor, Mauro Noel V. De Leon

Theses and Dissertations

Additive manufacturing (AM) and molding are manufacturing methods known for building representations or replicas of conceptualized engine components, but was considered impractical for manufacturing operating engine components. More recent technology has rendered composite materials (combining high-temperature polymers and fiber reinforcement) capable of withstanding the temperature and structural requirements to compete with conventional turbomachinery metals. This study explores the application of several high-temperature polymers (ULTEM 9085, Onyx-Carbon fiber, and Epoxy-Carbon fiber) and their survivability in the operating conditions of a P400 Engine compressor. The tests conducted for this study determined their viability as compressor materials. This study required conducting tensile specimen …

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Thermal Relaxation Of Shot Peen Induced Residual Stresses In A Nickel-Base Superalloy, Bryce E. Van Velson Mar 2022

Thermal Relaxation Of Shot Peen Induced Residual Stresses In A Nickel-Base Superalloy, Bryce E. Van Velson

Theses and Dissertations

Shot peening induces compressive residual stresses in components that positively influence fatigue life. Thermal and mechanical loading causes those residual stresses to relax. The hole drilling method and xray diffraction is used to measure the thermal relaxation of residual stresses in the nickel-base superalloy ME3.

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A Study On The Early Stages Of Degradation Of Multi-Component Alloy Surfaces In Extreme Environments Using The Multi-Cell Monte Carlo Method, Tyler D. Dolezal Mar 2022

A Study On The Early Stages Of Degradation Of Multi-Component Alloy Surfaces In Extreme Environments Using The Multi-Cell Monte Carlo Method, Tyler D. Dolezal

Theses and Dissertations

A computational toolset is presented and used in two examples that examined the interactions between structural materials and their extreme environments. A multi-cell Monte Carlo algorithm was developed to generate thermodynamically realistic solid-state alloy systems. These structures served as the foundation upon which surface slab models were generated. The tedious procedure of generating surface slab models from bulk structures was automated. The tools were used to study the high temperature surface corrosion resistance of a high-entropy alloy, Al10Nb15Ta5Ti30Zr40, and a nickel-based alloy, Ni70Nb10W20, under …

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Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz Mar 2022

Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz

Faculty Publications

Structural optimization is a methodology used to generate novel structures within a design space by finding a maximum or minimum point within a set of constraints. Topology optimization, as a subset of structural optimization, is often used as a means for light-weighting a structure while maintaining mechanical performance. This article presents the mathematical basis for topology optimization, focused primarily on the Bi-directional Evolutionary Structural Optimization (BESO) and Solid Isotropic Material with Penalization (SIMP) methodologies, then applying the SIMP methodology to a case study of additively manufactured lattice cells. Three lattice designs were used: the Diamond, I-WP, and Primitive cells. These …

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Facet Dependent Oxygen Evolution Activity Of Spinel Cobalt Oxides, Li-Hua Zhang, Hong-Yuan Chuai, Hai Liu, Qun Fan, Si-Yu Kuang, Sheng Zhang, Xin-Bin Ma Feb 2022

Facet Dependent Oxygen Evolution Activity Of Spinel Cobalt Oxides, Li-Hua Zhang, Hong-Yuan Chuai, Hai Liu, Qun Fan, Si-Yu Kuang, Sheng Zhang, Xin-Bin Ma

Journal of Electrochemistry

Water splitting is a promising technology to produce clean hydrogen if powered by renewable energies, where oxygen evolution is the rate determining step at an anode. Here we adjust the different crystal planes of the cobalt oxides catalyst to expose more effective active sites through a hydrothermal process, so as to improve the reaction activity for oxygen evolution. The samples were well characterized by TEM, SEM and XRD. Among the three synthetic crystal planes (100), (111) and (110) of spinel cobalt oxides, the (100) crystal plane has the highest intrinsic activity. Combining in-situ infrared and DFT calculations, we …

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Structural Degradation Of Ni-Rich Layered Oxide Cathode For Li-Ion Batteries, Jia-Yi Wang, Sheng-Nan Guo, Xin Wang, Lin Gu, Dong Su Feb 2022

Structural Degradation Of Ni-Rich Layered Oxide Cathode For Li-Ion Batteries, Jia-Yi Wang, Sheng-Nan Guo, Xin Wang, Lin Gu, Dong Su

Journal of Electrochemistry

Nickel(Ni)-rich layered oxide has been regarded as one of the most important cathode materials for the lithium-ion batteries because of its low cost and high energy density. However, the concerns in safety and durability of this compound are still challenging for its further development. On this account, the in-depth understanding in the structural factors determining its capacity attenuation is essential. In this review, we summarize the recent advances on the degradation mechanisms of Ni-rich layered oxide cathode. Progresses in the structure evolution of Ni-rich oxide are carefully combed in terms of inner evolution, surface evolution, and the property under thermal …

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Recent Advances In Structural Regulation On Non-Precious Metal Catalysts For Oxygen Reduction Reaction In Alkaline Electrolytes, Xue Wang, Li Zhang, Chang-Peng Liu, Jun-Jie Ge, Jian-Bing Zhu, Wei Xing Feb 2022

Recent Advances In Structural Regulation On Non-Precious Metal Catalysts For Oxygen Reduction Reaction In Alkaline Electrolytes, Xue Wang, Li Zhang, Chang-Peng Liu, Jun-Jie Ge, Jian-Bing Zhu, Wei Xing

Journal of Electrochemistry

Oxygen reduction reaction (ORR) in alkaline electrolytes is an important electrochemical process for metal-air batteries and anion exchange membrane fuel cells (AEMFCs). However, the sluggish kinetics spurs intensive research on searching robust electrocatalysts. Non-precious metal catalysts (NPMCs) that can circumvent the cost and scarcity issues associated with platinum (Pt)-based materials have been pursued and the challenges lie in the performance improvement to rival Pt-based benchmarks. As the composition and structure of the NPMCs have a significant impact on the catalytic performance, precise regulation on the catalyst structure holds great promise to bridge the activity gap between NPMCs and Pt-based benchmarks. …

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Selective Co2 Reduction To Formate On Heterostructured Sn/Sno2 Nanoparticles Promoted By Carbon Layer Networks, Xue Teng, Yanli Niu, Shuaiqi Gong, Xuan Liu, Zuofeng Chen Feb 2022

Selective Co2 Reduction To Formate On Heterostructured Sn/Sno2 Nanoparticles Promoted By Carbon Layer Networks, Xue Teng, Yanli Niu, Shuaiqi Gong, Xuan Liu, Zuofeng Chen

Journal of Electrochemistry

Tin (Sn)-based materials have emerged as promising electrocatalysts for selective reduction of CO2 to formate, but their overall performances are still limited by electrode structures which govern the accessibility to active sites, the electron transfer kinetics, and the catalytic stability. In this study, the heterostructured Sn/SnO2 nanoparticles dispersed by N-doped carbon layer networks (Sn/SnO2@NC) were synthesized by a melt-recrystallization method taking the low melting point of Sn (m.p. 232oC). The N-doped carbon layer networks derived from polydopamine could attract more electrons on the electrocatalyst, serve as conductive agents and protect the ultrafine nanoparticles from …

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Mass Loading Optimization For Ethylene Glycol Oxidation At Different Potential Regions, Sheng-Nan Sun, Zhi-Chuan Xu Feb 2022

Mass Loading Optimization For Ethylene Glycol Oxidation At Different Potential Regions, Sheng-Nan Sun, Zhi-Chuan Xu

Journal of Electrochemistry

Designing and fabricating the electrocatalysts is attracting more and more attention in recent years due to a global interest in developing techniques for electrochemical energy conversion and storage, as well as elelectro-synthesis of valuable chemicals. The activity is one of the key performance parameters for electrocatalysts, while the observed activity can be affected by mass loading of electrocatalysts. Here, we take cobalt oxide (Co3O4)/graphite paper electrode (Co3O4/GPE) as a model electrode to demon-strate how the mass loading of Co3O4 catalyst influences ethylene glycol (EG) oxidation in alkaline (KOH) by …

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Recent Advances In Electrochemical Kinetics Simulations And Their Applications In Pt-Based Fuel Cells, Ji-Li Li, Ye-Fei Li, Zhi-Pan Liu Feb 2022

Recent Advances In Electrochemical Kinetics Simulations And Their Applications In Pt-Based Fuel Cells, Ji-Li Li, Ye-Fei Li, Zhi-Pan Liu

Journal of Electrochemistry

Theoretical simulations of electrocatalysis are vital for understanding the mechanism of the electrochemical process at the atomic level. It can help to reveal the in-situ structures of electrode surfaces and establish the microscopic mechanism of electrocatalysis, thereby solving the problems such as electrode oxidation and corrosion. However, there are still many problems in the theoretical electrochemical simulations, including the solvation effects, the electric double layer, and the structural transformation of electrodes. Here we review recent advances of theoretical methods in electrochemical modeling, in particular, the double reference approach, the periodic continuum solvation model based on the modified Poisson-Boltzmann …

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Magnetic Resonance In Metal-Ion Batteries: From Nmr (Nuclear Magnetic Resonance) To Epr (Electron Paramagnetic Resonance), Bing-Wen Hu, Chao Li, Fu-Shan Geng, Ming Shen Feb 2022

Magnetic Resonance In Metal-Ion Batteries: From Nmr (Nuclear Magnetic Resonance) To Epr (Electron Paramagnetic Resonance), Bing-Wen Hu, Chao Li, Fu-Shan Geng, Ming Shen

Journal of Electrochemistry

Metal-ion batteries have changed our quotidian lives. The research on the electrode materials for metal-ion battery is the key to improve the performance of the battery. Therefore, understanding the structure-performance relationship of the electrode materials can help to improve the energy density and power density of the materials. Magnetic resonance, including nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR), has been continuously improved during the past three decades, and has gradually become one of the important technologies to study the structure-performance relationship of electrode materials. This paper summarizes the progress of magnetic resonance research from our group on several …

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Resilient Modulus Of Siliciclastic Unbound Granular Materials Under Repeated Wheel Loading, Siya Rimoyi Feb 2022

Resilient Modulus Of Siliciclastic Unbound Granular Materials Under Repeated Wheel Loading, Siya Rimoyi

Tanzania Journal of Engineering and Technology (TJET)

The Resilient Modulus (Mr) is a fundamental material property input in modern Mechanistic-Empirical (M-E) pavements structural design. Empirical pavement design methods have been in use over a long period during which large databases of four- days-soaked California Bearing Ratio (CBR) values at or near the Maximum Dry Density have been generated in the strength assessments for Unbound Granular Materials (UGMs). In the adoption of the M-E design approach researchers have so far attempted with various degrees of success to develop models to derive resilient modulus from the conventional CBR-based databases. This study provides an extensive laboratory experimental study to investigate …

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Development Of Intensity-Duration-Frequency (Idf) Models For Manually Operated Rain Gauge Catchment: A Case Study Of Port Harcourt Metropolis Using 50 Years Rainfall Data, Francis Ogbozige Feb 2022

Development Of Intensity-Duration-Frequency (Idf) Models For Manually Operated Rain Gauge Catchment: A Case Study Of Port Harcourt Metropolis Using 50 Years Rainfall Data, Francis Ogbozige

Tanzania Journal of Engineering and Technology (TJET)

Hydraulic structures such as surface drainages and culverts are usually constructed in urban areas with the intention of draining runoff into nearby streams and rivers in order to avoid flooding. However, most of these structures frequently fail to serve the intended use due to the occurrence of high intensity rainfall accompanied with long duration, which produce runoff discharge higher than their designed capacities. This is common in many developing countries as drainages and culverts are most times constructed without considering hydrological analysis of the catchment. Hence, this research considered Port Harcourt city as a case study by utilizing 50 years …

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Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu Feb 2022

Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu

Tanzania Journal of Engineering and Technology (TJET)

Gesture recognition is broadly utilized within the field of sensing. There are basically three gesture recognition methods based on computer vision, depth sensor and motion sensor. Motion sensor-based gesture recognition has few input data, fast speed, and direct access to three- dimensional information of the hand. The advantages of traditional motion sensor-based gesture recognition have gradually become a current research hotspot. The essence of traditional motion sensor-based gesture recognition is a pattern recognition problem, and its accuracy depends heavily on the feature dataset extracted from prior experience. Unlike traditional pattern recognition methods, deep learning can be used to a large …

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Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John Feb 2022

Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John

Tanzania Journal of Engineering and Technology (TJET)

In portfolio optimization, the fundamental goal of an investor is to optimally allocate investments between different assets. Mean-variance optimization methods make unrealistic assumptions to solve the problem of optimal allocation. On the other hand, when realistic constraints like holding size and cardinality are introduced it leads to optimal asset allocation which differ from the mean variance optimization. The resulting optimization problem become quite complex as it exhibits multiple local extrema and discontinuities. Heuristic algorithms work well for the complex problem. Therefore, a heuristic algorithm is developed which is based on hill climbing complete (HC-C). It is utilized to solve the …

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Assessment Of Quality Of Fresh Concrete Delivered At Varying Temperatures, Maroua Saidi, Kazem Jadidi, Moses Karakouzian Feb 2022

Assessment Of Quality Of Fresh Concrete Delivered At Varying Temperatures, Maroua Saidi, Kazem Jadidi, Moses Karakouzian

Civil and Environmental Engineering and Construction Faculty Research

Concrete is increasingly utilized in the construction field in Southern Nevada. This area has an arid and hot summer and freezing cold winter conditions. These extreme conditions affect the properties of fresh concrete, which can cause cracking. Hot weather conditions may adversely affect both fresh and hardened concrete properties. Even though practices can minimize the detrimental effects, good quality control of fresh concrete, from mixing to finishing, is crucial under hot weather conditions. The objective of the present study is to evaluate the seasonal consistency of concrete quality, considering strength and slump properties. Another objective of this research is to …

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Efficacy Of Softener For Enhancing Fatigue And Low-Temperature Performance Of Asphalt Binders With High Rap, Sumon Roy Feb 2022

Efficacy Of Softener For Enhancing Fatigue And Low-Temperature Performance Of Asphalt Binders With High Rap, Sumon Roy

Student Theses and Dissertations

The use of a higher percentage of reclaimed asphalt pavement (RAP) in asphalt concrete can lead to developing premature failure of asphalt pavements due to fatigue and/or low-temperature cracking. The incorporation of softening agents in asphalt binders can resolve these problems and enhance pavement durability. This study aims to evaluate the effectiveness of waste-based softening agents for enhancing the properties of asphalt mixes with high RAP contents. Waste cooking oil (WCO), and engine bottom oil (EBO) along with a commercial rejuvenator were investigated in this study. Three types of Performance Grade (PG) binders, each collected from two different sources, used …

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