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2023

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Articles 61 - 90 of 910

Full-Text Articles in Materials Science and Engineering

Synergistic Strategies In Sinter-Based Material Extrusion (Mex) 3d Printing Of Copper: Process Development, Product Design, Predictive Maps And Models., Kameswara Pavan Kumar Ajjarapu Dec 2023

Synergistic Strategies In Sinter-Based Material Extrusion (Mex) 3d Printing Of Copper: Process Development, Product Design, Predictive Maps And Models., Kameswara Pavan Kumar Ajjarapu

Electronic Theses and Dissertations

3D printing pure copper with high electrical conductivity and exceptional density has long been challenging. While laser-based additive manufacturing technologies suffered due to copper's highly reflective nature towards laser beams, parts printed via binder-assisted technologies failed to reach over 90% IACS (International Annealed Copper Standard), electrical conductivity. Although promising techniques such as binder jetting, filament, and pellet-based 3D printing that can print copper exist, they however still face difficulties in achieving both high sintered densities and electrical conductivity values. This is due to a lack of comprehensive understanding of property evolution from green to sintered states and the strategies that …


Additive Manufacturing Of Microelectronic Devices For Extreme Environments, Nicholas Mckibben Dec 2023

Additive Manufacturing Of Microelectronic Devices For Extreme Environments, Nicholas Mckibben

Boise State University Theses and Dissertations

This work encompasses a comprehensive exploration of advanced manufacturing techniques for fabricating microelectronic devices compatible with extreme environments. The research integrates the fields of chemistry, nanomaterials, and additive manufacturing to achieve remarkable progress in sensor development, with a particular emphasis on aerosol jet printing (AJP), surface acoustic wave (SAW) devices, patterned graphene growth, and surface functionalization. The investigation begins with the AJP process development of a commercial silver nanoparticle ink, culminating in the fabrication of a piezoelectric SAW transducer that was prototyped as a high-temperature thermometer, showing excellent linearity when validated to 200°C. Next, the investigation continued with the development …


Novel Sensors And Measurement Techniques For Thermal Properties In Extreme Environments, Katelyn Wada Dec 2023

Novel Sensors And Measurement Techniques For Thermal Properties In Extreme Environments, Katelyn Wada

Boise State University Theses and Dissertations

Advancements in thermal properties analysis is crucial for improvement of existing and next generation reactors, space exploration, and environmental safety. Extreme environments pose a great hurdle for instrumentation to measure real time thermal properties due to the extreme temperatures, high radiation, and variable electromagnetic environments. Nevertheless, measurement systems are tremendously important for the design, P.E.rformance, and safety considerations of nuclear fuels, space crafts, and deep sea/deep earth drilling. Thermal properties may change significantly in these environments creating challenging problems for temperature and thermal conductivity measurement systems. A recent focus has surrounded improvements in such systems for accurate determination of temperature …


Engineered Biomass-Derived Carbon Adsorbents For Targeted Contaminant Remediation From Aqueous Environments, Suraj Venkat Pochampally Dec 2023

Engineered Biomass-Derived Carbon Adsorbents For Targeted Contaminant Remediation From Aqueous Environments, Suraj Venkat Pochampally

UNLV Theses, Dissertations, Professional Papers, and Capstones

Porous carbon adsorbents like biochar (BC) are produced from waste biomasses like wood chips, animal litter, nut shells, dried grass, etc. to be used in a multitude of applications like gas capture, soil amendment, water treatment, electrode materials, etc. In water treatment, carbon-based adsorbents have been mainly used to physically or chemically adsorb contaminants depending on the adsorption mechanism. However, BCs in their raw state do not have the capability of absorbing high amounts of contaminants and need to be activated/ modified for the pore network to broaden and adsorb the contaminants with better efficiency.

The scope of this dissertation …


Sustainable Diamond-Like Carbon Fabricated Gravure Cylinders For Printing Fine Lines Of Electrodes And Graphic Structures, Chandramohan Seetharamiah Srinivasaraju Dec 2023

Sustainable Diamond-Like Carbon Fabricated Gravure Cylinders For Printing Fine Lines Of Electrodes And Graphic Structures, Chandramohan Seetharamiah Srinivasaraju

Dissertations

The main objective of this work is to evaluate the potential of Diamond-Like Carbon (DLC) as an alternative to chrome for use on gravure cylinders. DLC coatings consist of carbon atoms, arranged into a diamond-like structure that closely resembles that of natural diamond. In contrast to chrome, DLC is environmentally friendly. The focus of the study is to determine the viability of DLC as a substitute material for chrome to be used on gravure cylinders by determining key material properties and evaluating printing performance.

In the first research paper, four DLC variants (Standard DLC, A-DLC, S-DLC, and Organic Silica) and …


3d Printed Microdialysis-Based Microsampling Probes, Patrick Pysz Dec 2023

3d Printed Microdialysis-Based Microsampling Probes, Patrick Pysz

Graduate Theses and Dissertations

This work will show the development of a fully 3D printed device platform in which a complex microsampling probe geometry is fabricated in a simple two-step process. This process includes the combination of 2-photon polymerization (2PP) and masked-stereolithography (MSLA). The cutting edge neurotechnology needed to monitor brain internal communication and will require multiple sensing modalities including temperature, pressure, electrophysiological, and optogenetics. Microsampling is an integrally important function for any future biosensing device platform as it allows for chemical delivery and unparalleled specificity through offline analysis of collection samples. Stereolithography (SLA) 3D printing has emerged as a powerful fabrication method capable …


An Icfd Fluid Model Used In A Mash Tl-6 Vehicle Model, Md Zunayed Habib Dec 2023

An Icfd Fluid Model Used In A Mash Tl-6 Vehicle Model, Md Zunayed Habib

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The objective of this thesis was to develop an ICFD finite element model of a partially filled deformable container suitable for impact scenarios. This model will be later incorporated into the existing TL-6 vehicle model, which is a tractor-tank trailer vehicle model. Previous finite element fluid models for the TL-6 vehicle used an elastic fluid model, which could not predict the fluid behavior correctly.

A study was conducted on the ICFD modeling and an improved ICFD model has been developed using the LS-DYNA, a finite element analysis software. Different properties and parameters of the fluid and the container were adopted …


Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise Dec 2023

Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …


Experimental Analysis Of Nonlinear Wave Propagation In Bistable Mechanical Metamaterials With A Defect, Samuel R. Harre Dec 2023

Experimental Analysis Of Nonlinear Wave Propagation In Bistable Mechanical Metamaterials With A Defect, Samuel R. Harre

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Mechanical metamaterials built up of compliant units can support the propagation of linear and nonlinear waves. A popular architecture consists of a one-dimensional chain of bistable elements connected by linear springs. This type of chain can support nonlinear transition waves that switch each element from one stable state to the other as they propagate along the chain. One way to manipulate the propagation of such waves is via introduction of a local inhomogeneity, i.e., a defect in the otherwise periodic chain. Recent analytical and numerical work has shown that based on its initial velocity, a transition wave may be reflected, …


Study On Effect Of 3d Printing Parameters On Surface Roughness And Tensile Strength Using Analysis Of Variance, Faqih Fadillah, Heru Suryanto, Suprayitno Suprayitno Nov 2023

Study On Effect Of 3d Printing Parameters On Surface Roughness And Tensile Strength Using Analysis Of Variance, Faqih Fadillah, Heru Suryanto, Suprayitno Suprayitno

Journal of Mechanical Engineering Science and Technology (JMEST)

Fused deposition modeling of 3D printing is the process of making workpieces or parts by adding filaments to each layer. Some indicators of a high-quality product of 3D printing are the precisions dimensions, the surface roughness, and tensile strength. This research aims to find the parameters most affecting surface roughness and tensile strength. The research design used an experimental method with input parameters: (1) print speed (15-35 mm/s), (2) print temperature (200-210C), (3) layer height (0.1 – 0.3 mm), (4) infill line directions (0-90), and dependent variables were surface roughness and tensile strength. The data distribution used the L9 orthogonal …


Mechanical Characterization Of Naoh-Treated Agel Fiber-Cotton Composites, I Gusti Ngurah Nitya Santhiarsa, I Gusti Bagus Wijaya Kusuma, I Gede Artha Negara Nov 2023

Mechanical Characterization Of Naoh-Treated Agel Fiber-Cotton Composites, I Gusti Ngurah Nitya Santhiarsa, I Gusti Bagus Wijaya Kusuma, I Gede Artha Negara

Journal of Mechanical Engineering Science and Technology (JMEST)

Composites comprising two or more distinct materials are fabricated to enhance the mechanical properties of the constituent materials. A common approach for generating composites is vacuum infusion. This technique enables the infusion of two materials utilizing a vacuum. In the field of composite science, textile composites have emerged as an important new development. Agel rope, derived from twisting agel fibers, exhibits inferior bending strength and elongation compared to ropes fabricated from synthetic fibers. Moreover, agel rope is susceptible to bacterial decay. This study aims to characterize the mechanical properties of textile composites comprising woven agel rope subjected to NaOH treatment. …


Heat Conduction In Cylindrical Coordinates With Time-Varying Conduction Coefficients: A Practical Engineering Approach, Lulut Alfaris, Ruben Cornelius Siagian, Aldi Cahya Muhammad, Ukta Indra Nyuswantoro, Budiman Nasution Nov 2023

Heat Conduction In Cylindrical Coordinates With Time-Varying Conduction Coefficients: A Practical Engineering Approach, Lulut Alfaris, Ruben Cornelius Siagian, Aldi Cahya Muhammad, Ukta Indra Nyuswantoro, Budiman Nasution

Journal of Mechanical Engineering Science and Technology (JMEST)

This research aims to develop a mathematical method for expressing the Laplace operator in cylindrical coordinates and applying it to solve heat conduction equations in various scenarios. The method commences by transforming Cartesian coordinates into cylindrical coordinates and identifying the necessary substitutions. The result is the expression of the Laplace operator in cylindrical coordinates, which is subsequently employed to address heat conduction equations within cylindrical coordinates. Various cases encompassing different initial and boundary conditions, as well as variations in the conduction coefficient over time, are meticulously considered. In each instance, precise mathematical solutions are determined and subjected to thorough analysis. …


Numerical Study On Resistance Of Stepped Planing Hull, Fajri Ashfi Rayhan, Andika Masrul, Arya Khairullah Akbar, Bima Anugerah Putra Nov 2023

Numerical Study On Resistance Of Stepped Planing Hull, Fajri Ashfi Rayhan, Andika Masrul, Arya Khairullah Akbar, Bima Anugerah Putra

Journal of Mechanical Engineering Science and Technology (JMEST)

A stepped planing hull, also known as a step hull, is a hull modification that reduces the wetted surface area. Although this type of hull has proven effective in several ships, it is still rarely used. The step hull possesses numerous advantages that make it ideal for activities involving small and fast boats. However, regrettably, its full potential remains untapped at present. The purpose of this study was to identify the effect of variations in the angle of the step hull on resistance or drag. The study utilized the CFD method, and three hull configuration models were used at each …


Analyzing Transition Metallic Catalytic Converter Impact On Four-Stroke Motorcycle Fuel Consumption, Sudirman Rizki Ariyanto, Ata Syifa’ Nugraha, Wahyu Robby Cahyadi, Yelma Dianastiti, Muhammad Yandi Pratama Nov 2023

Analyzing Transition Metallic Catalytic Converter Impact On Four-Stroke Motorcycle Fuel Consumption, Sudirman Rizki Ariyanto, Ata Syifa’ Nugraha, Wahyu Robby Cahyadi, Yelma Dianastiti, Muhammad Yandi Pratama

Journal of Mechanical Engineering Science and Technology (JMEST)

Increased exhaust emissions from motor vehicles have become a major concern in efforts to reduce air pollution. One developed solution is the use of transition metallic catalytic converter (TMCC) technology in vehicle exhaust systems. This study aims to compare the fuel consumption efficiency of three types of exhaust systems, namely standard exhaust without a catalyst (STD WC), the standard exhaust with Original Equipment Manufacturer catalyst (STD OEM), and an exhaust system equipped with a Copper-Coated Chrome Metallic Catalytic Converter (TMCC CuCr). The data analysis method employed a quantitative approach by collecting fuel consumption data at each rpm and analyzing the …


Effect Of The Homogenization Process On Titanium Oxide-Reinforced Nanocellulose Composite Membranes, Taufiq Mahsuli, Aisyah Larasati, Aminnudin Aminnudin, Jibril Maulana Nov 2023

Effect Of The Homogenization Process On Titanium Oxide-Reinforced Nanocellulose Composite Membranes, Taufiq Mahsuli, Aisyah Larasati, Aminnudin Aminnudin, Jibril Maulana

Journal of Mechanical Engineering Science and Technology (JMEST)

Indonesian pineapple production can reach 200 tons per day; however, pineapples generate a significant amount of waste. Pineapple peel waste can be used to make membranes. Composite membranes containing TiO2 have dense properties, low porosity, and increase the mechanical strength of the cellulose sheet. This research uses various ultrasonic homogenizers to homogenize the distribution of nanocellulose and TiO2 (50% and 100% power with 30, 60, and 90 minutes). The casting method is used to shape the membrane. The SEM test shows that the higher the power used and the longer the sonication time, the less agglomeration of about 1.63%/ cm2 …


Effect Of Heating Temperature, Holding Time And Stabilization Temperature On The Al-Foam Properties, Dewi Puspitasari, Poppy Puspitasari, Mazli Mustapha, Turnad Lenggo Ginta Nov 2023

Effect Of Heating Temperature, Holding Time And Stabilization Temperature On The Al-Foam Properties, Dewi Puspitasari, Poppy Puspitasari, Mazli Mustapha, Turnad Lenggo Ginta

Journal of Mechanical Engineering Science and Technology (JMEST)

The interest in metallic foam is increasing since their cellular structures have a unique combination of properties such as high stiffness, low density, lightweight, high specific strength, and thermal insulation. Commonly, the performance of metallic foam can be improved by the heat treatment process. However, the previous heat treatment methods still present the brittle crack path and the research on heat treatments of the metal foam properties is very limited. In this study, individual parameters in stress relieving treatment that contribute to Al-Foam properties were investigated. The stress-relieving process of the samples was performed using a vacuum furnace. The composition …


Vertical Shaft Kinetic Turbine Performance Using A Cup-Shape Blade, Kennie A. Lempoy, Nita C. V. Monintja, Arwanto M. A. Lakat Nov 2023

Vertical Shaft Kinetic Turbine Performance Using A Cup-Shape Blade, Kennie A. Lempoy, Nita C. V. Monintja, Arwanto M. A. Lakat

Journal of Mechanical Engineering Science and Technology (JMEST)

The abundant availability of alternative energy sources forms the fundamental foundation for rural energy development. In particular, renewable energy sources are indispensable in rural areas due to their ecofriendly nature and widespread accessibility, which helps preserve the environment by avoiding pollution. Indonesia, a country blessed with vast water resources, especially its rivers, holds enormous potential for harnessing kinetic energy derived from fast-flowing river waters. Effective utilization of this kinetic energy has the potential to address energy shortages in the country. In this context, there is a pressing need to enhance the efficiency of kinetic turbines designed to function as electricity …


Photocatalytic Scheme With External Magnetic Field On Coffee Waste In Hydrogen Production, Abid Fahreza Alphanoda, Eko Prasetyo, Wisnu Broto Nov 2023

Photocatalytic Scheme With External Magnetic Field On Coffee Waste In Hydrogen Production, Abid Fahreza Alphanoda, Eko Prasetyo, Wisnu Broto

Journal of Mechanical Engineering Science and Technology (JMEST)

Photocatalytic is considered a deadlock-breaking technology for renewable energy and lowering environmental pollutants. Photocatalytic efficiency efforts are improved by activating the photocatalyst to introduce an external magnetic field. This review highlights recent breakthroughs by comparing original coffee waste, activation of coffee waste with the addition of catalysts, and manipulation of spin electrons by applying external magnets. Characterization was done with FTIR to look at chemical bonds, UV-Vis with Tauc's Relation approach to measure bandgap, and material morphology using SEM EDX. The increase in photocatalyst activation aligns with the decrease in bandgap value. The rate of decline in bandgap is in …


Artificial Neural Network-Based Modeling Of Performance Spark Ignition Engine Fuelled With Bioethanol And Gasoline, Susi Marianingsih, Farhanna Mar’I, Hendry Y. Nanlohy Nov 2023

Artificial Neural Network-Based Modeling Of Performance Spark Ignition Engine Fuelled With Bioethanol And Gasoline, Susi Marianingsih, Farhanna Mar’I, Hendry Y. Nanlohy

Journal of Mechanical Engineering Science and Technology (JMEST)

Machine learning technology can distinguish the relationship between engine characteristics and performances. Therefore, the goal of the present work is to predict the performance parameters of a singlecylinder 4-stroke gasoline engine at different ignition timings using a blended mixture of gasoline and bioethanol by an artificial neural network (ANN). Experimental data for training and testing in the proposed ANN was obtained at a dynamic speed and full load condition. An ANN model was developed based on standard Back-Propagation algorithm for the spark ignition engine. Multi-layer perception network (MLP) was used for non-linear mapping between the input and output parameters. An …


The Effect Of Adding Aluminium On The Performance Of Zno Nrs/Pani In Their Application As Photoelectrochemical Water Splitting, Eprilia Trikusuma Sari, Nandang Mufti, Anissa Chairani Alfin Nadhira, Hari Wisodo, Markus Diantoro Nov 2023

The Effect Of Adding Aluminium On The Performance Of Zno Nrs/Pani In Their Application As Photoelectrochemical Water Splitting, Eprilia Trikusuma Sari, Nandang Mufti, Anissa Chairani Alfin Nadhira, Hari Wisodo, Markus Diantoro

Journal of Mechanical Engineering Science and Technology (JMEST)

Photoelectrochemical (PEC) is a new renewable energy technology that converts H2O into hydrogen and oxygen gas with the help of sunlight. A photoelectrochemical cell device consists of three main components, one of which is the photoanode. One of the materials that can be used as a photoanode is ZnO which has good electrical properties and is non-toxic. Nanorods-structured ZnO has the advantage of being able to increase light absorption due to its high surface area. However, the resulting performance is still quite low. So it is necessary to make modifications to the photoanode, one of which is by adding aluminium …


Lif-Sn Composite Modification Layer To Modify Garnet/Lithium Metal Interface, Wu Yang, Xue-Fan Zheng, Yu-Qi Wu, Zheng-Liang Gong Nov 2023

Lif-Sn Composite Modification Layer To Modify Garnet/Lithium Metal Interface, Wu Yang, Xue-Fan Zheng, Yu-Qi Wu, Zheng-Liang Gong

Journal of Electrochemistry

The growing demands for electric vehicles and consumer electronics; as well as the expanding renewable energy storage market; have promoted extensive research on energy storage technologies with low costhigh energy density and safety. Lithium (Li) metal and solid-state electrolytes are considered as important components for next-generation batteries because of their great potential for improvements in energy density and safety performance. Inorganic garnet-type solid electrolytes with high Li-ion conductivity (about 10-3 S·cm-1) and high shear modulus (55 GPa) are considered to be ideal solid-state electrolytes; however; the issue of Li dendrite growth still obstructs their practical application. Herein; …


Constructing Carbon-Encapsulated Nifev-Based Electrocatalysts By Alkoxide-Based Self-Template Method For Oxygen Evolution Reaction, En-Hui Ma, Xu-Po Liu, Tao Shen, De-Li Wang Nov 2023

Constructing Carbon-Encapsulated Nifev-Based Electrocatalysts By Alkoxide-Based Self-Template Method For Oxygen Evolution Reaction, En-Hui Ma, Xu-Po Liu, Tao Shen, De-Li Wang

Journal of Electrochemistry

The development of green and sustainable water-splitting hydrogen production technology is beneficial to reducing the over-reliance on fossil fuels and realizing the strategic goal of "carbon neutral". As one of the half reactions for water splitting, oxygen evolution reaction has suffered the problems of sluggish four-electron transfer process and relatively slow reaction kinetics. Therefore, exploring efficient and stable catalysts for oxygen evolution reaction is of critical importance for water-splitting technology. Metal alkoxides are a series of compounds formed by the coordination function of metal ions with alcohol molecules. Metal alkoxides possess the double advantages of organic materials and inorganic materials, …


Preparation And Lithium Storage Properties Of Carbon Confined Li3Vo4 Nano Materials, Jia-Qi Fan, Huan-Qiao Song, Jia-Ying An, Amantai A-Yi-Da-Na, Mo Chen Nov 2023

Preparation And Lithium Storage Properties Of Carbon Confined Li3Vo4 Nano Materials, Jia-Qi Fan, Huan-Qiao Song, Jia-Ying An, Amantai A-Yi-Da-Na, Mo Chen

Journal of Electrochemistry

Li3VO4, as a promising anode material for lithium ion batteries, has been widely studied because of its low and safe voltage, and large capacity. However, its poor electronic conductivity impedes the practical application of Li3VO4 particularly at high rates. In this paper, carbon confined Li3VO4 nano materials (Li3VO4/C) were synthesized by hydrothermal and solid-phase method, and for comparison, the Li3VO4 (N) nano materials without carbon confinement and Li3VO4 (B) materials were also synthesized by pure solid-phase method. The composition, structure, …


Peg-Water Electrolyte For High-Performance Zinc Iodine Dual-Ion Batteries, Xiao-Feng Qu, Yu-Ting Tang, Xin-Cheng He, Jia-Sheng Zhou, Zi-Heng Tang, Wen-Hua Feng, Jun Liu Nov 2023

Peg-Water Electrolyte For High-Performance Zinc Iodine Dual-Ion Batteries, Xiao-Feng Qu, Yu-Ting Tang, Xin-Cheng He, Jia-Sheng Zhou, Zi-Heng Tang, Wen-Hua Feng, Jun Liu

Journal of Electrochemistry

Thanks to abundant resource and rapid redox reaction kinetics, iodine is regarded as promising positive materials inthe batteries. However, the shuttling effect due to the high solubility of iodine in the electrolyte makes the performance of battery poor. In this paper, polyethylene glycol (PEG400) and potassium iodide were added into zinc-ion aqueous electrolyte. PEG400 could complex with iodine to reduce the dissolution of iodine, therefore alleviating the formation of soluble triiodide (I3) from iodine and iodide ions. Furthermore, this electrolyte was used in the battery with double carbon cloths as the current collectors, double separators and zinc …


Study On Performance And Dynamic Response Of Composite Stress Absorber Layer, Yang Sanqiang, Li Pengfei, Liu Lu, Cao Zilong Nov 2023

Study On Performance And Dynamic Response Of Composite Stress Absorber Layer, Yang Sanqiang, Li Pengfei, Liu Lu, Cao Zilong

Journal of China & Foreign Highway

In order to compare the performance difference among the composite stress absorption layer, SBS stress absorption layer, and glass grille stress absorption layer, the dynamic response law of the composite stress absorption layer was explored. In this paper, based on the composite stress absorption layer composed of glass grille + rubber-modified asphalt gravel sealing layer, the UTM-25 test system was employed to carry out inter-layer shear, inter-layer tension, low temperature bending, and four-point fatigue test. By laying test sections and sensors, strain information of the stress absorption layer under different conditions was collected. It was found that the bonding force …


The Effects Of Engineering Summer Camps On Middle And High School Students’ Engineering Interest And Identity Formation: A Multi-Methods Study, Timothy Robinson, Adam Kirn, Jenny Amos, Indira Chatterjee Nov 2023

The Effects Of Engineering Summer Camps On Middle And High School Students’ Engineering Interest And Identity Formation: A Multi-Methods Study, Timothy Robinson, Adam Kirn, Jenny Amos, Indira Chatterjee

Journal of Pre-College Engineering Education Research (J-PEER)

This multi-methods study explores changes in engineering interest and identity of middle and high school students (n = 79) attending introductory-level engineering summer camps at a large western land grant university. Middle school is a critical time when student interest, identity, and subsequently career choice begin to emerge and hence it is important that at this age students are given accurate information about engineering majors in college and future career opportunities in engineering. Data were collected over a period of two years in six summer camps. Three separate populations of middle and high school students participated in the summer …


Pursuing Excitonic Energy Transfer With Programmable Dna-Based Optical Breadboards, Divita Mathur, Sebastián A. Díaz, Niko Hildebrandt, Ryan D. Pensack, Bernard Yurke, Austin Biaggne, Lan Li, Joseph S. Melinger, Mario G. Ancona, William B. Knowlton, Igor L. Medintz Nov 2023

Pursuing Excitonic Energy Transfer With Programmable Dna-Based Optical Breadboards, Divita Mathur, Sebastián A. Díaz, Niko Hildebrandt, Ryan D. Pensack, Bernard Yurke, Austin Biaggne, Lan Li, Joseph S. Melinger, Mario G. Ancona, William B. Knowlton, Igor L. Medintz

Materials Science and Engineering Faculty Publications and Presentations

DNA nanotechnology has now enabled the self-assembly of almost any prescribed 3-dimensional nanoscale structure in large numbers and with high fidelity. These structures are also amenable to site-specific modification with a variety of small molecules ranging from drugs to reporter dyes. Beyond obvious application in biotechnology, such DNA structures are being pursued as programmable nanoscale optical breadboards where multiple different/identical fluorophores can be positioned with sub-nanometer resolution in a manner designed to allow them to engage in multistep excitonic energy-transfer (ET) via Förster resonance energy transfer (FRET) or other related processes. Not only is the ability to create such complex …


Atomistic-Informed And Machine Learning-Assisted Crystal Plasticity Modeling For Materials Interface, Ibrahim Altarabsheh Nov 2023

Atomistic-Informed And Machine Learning-Assisted Crystal Plasticity Modeling For Materials Interface, Ibrahim Altarabsheh

Doctoral Dissertations

This dissertation presents a comprehensive study that addresses two critical challenges in the field of computational materials science and engineering from nano- to mesoscale. First, to overcome the well-acknowledged length scale limitation associated with atomistic simulations, a novel two-step approach is introduced for a probabilistic prediction of stress-strain curves in terms of material volume. The method combines Molecular Dynamics (MD) simulations and a multioutput Gaussian process (MOGP) with Bayesian analysis to model stress-strain behavior and predict stress and strain values. The model effectively captures the intricate three-stage curve shape exhibited in stress-strain plots, discerning key points such as yielding, hardening, …


Carrier Dynamics In Green Iii-Nitride Leds Using Small-Signal Electroluminescence, Xuefeng Li Nov 2023

Carrier Dynamics In Green Iii-Nitride Leds Using Small-Signal Electroluminescence, Xuefeng Li

Optical Science and Engineering ETDs

Solid-state lighting has achieved significant success over the past two decades, but the low quantum efficiency of green LEDs (i.e., the “green gap”) remains a barrier to full red-green-blue (RGB) displays in numerous applications. Combating efficiency reduction in longer-wavelength LEDs requires understanding the relative roles of intrinsic effects (e.g., wave-function overlap, carrier-current density relationship, phase-space filling (PSF)) vs. extrinsic effects (e.g., material degradation due to increased defect density, compositional inhomogeneities, etc.). A systematic study of the carrier dynamics in InGaN/GaN LEDs is very important for understanding the origin of the green gap and for providing solutions to improve the efficiency …


Modeling Hydration Kinetics Of Sustainable Cementitious Binders Using An Advanced Nucleation And Growth Approach, Taihao Han, Jie Huang, Gaurav Sant, Narayanan Neithalath, Ashutosh Goel, Aditya Kumar Nov 2023

Modeling Hydration Kinetics Of Sustainable Cementitious Binders Using An Advanced Nucleation And Growth Approach, Taihao Han, Jie Huang, Gaurav Sant, Narayanan Neithalath, Ashutosh Goel, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

Supplementary cementitious materials (SCMs) are utilized to partially substitute Portland cement (PC) in binders, reducing carbon-footprint and maintaining excellent performance. Nonetheless, predicting the hydration kinetics of [PC + SCM] binders is challenging for current analytical models due to the extensive diversity of chemical compositions and molecular structures present in both SCMs and PC. This study develops an advanced phase boundary nucleation and growth (pBNG) model to yield a priori predictions of hydration kinetics—i.e., time-resolved exothermic heat release profiles—of [PC + SCM] binders. The advanced pBNG model integrates artificial intelligence as an add-on, enabling it to accurately simulate hydration kinetics for …