Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Engineering Science and Materials

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1141 - 1170 of 5701

Full-Text Articles in Engineering

Laser Powder Bed Fusion Process, Structure, And Properties: Holistic Approach To Establishing Metallurgical Quality, Hunter Taylor Dec 2022

Laser Powder Bed Fusion Process, Structure, And Properties: Holistic Approach To Establishing Metallurgical Quality, Hunter Taylor

Open Access Theses & Dissertations

The advent of metal additive manufacturing (AM) was posed as a disruption to casting, forging, machining, and forming with the notion "complexity is free". However, since invention in the late 1990's the marketed potential has not been realized. Metal based AM is best viewed from the process-structure-properties-performance (PSPP) paradigm taught in material science and engineering, which links the process history to the part performance. Understanding the complex and localized process control made available by AM creates a significant challenge in defining the materials structure, properties, and performance. The lack of holistic understating of inputs and corresponding results has been identified …

Go to article

Using Ultrasonication For The Improvement Of Grade And Recovery In Molybdenum Sulfide Flotation, Wayne Alexander Campbell Dec 2022

Using Ultrasonication For The Improvement Of Grade And Recovery In Molybdenum Sulfide Flotation, Wayne Alexander Campbell

Open Access Theses & Dissertations

Experimentation was performed on molybdenite slurry by using ultrasonication to elucidate the effects of ultrasonic-induced bubble cavitation on the grade, recovery, and gangue reduction during small-scale flotation tests and was followed by a topographical analysis of quartz particles using SEM. Ultrasonic waves at 20-80 kHz that propagate through a liquid medium cause microbubbles to form, grow, and implode. The cavitation bubble's implosion causes brief extreme local conditions where temperatures can reach 5,000 K and pressures of 1,000 bar. The resulting microjets create mechanical and chemical changes to the system and were directed at improving flotation dynamics in these experiments. Through …

Go to article

An Application Of Optimized Bistable Laminates As A Low Velocity, Low Impact Mechanical Deterrent, Graham Lancaster Dec 2022

An Application Of Optimized Bistable Laminates As A Low Velocity, Low Impact Mechanical Deterrent, Graham Lancaster

All Theses

This research considers the problem of using bistable laminates as a mechanical deterrent to the impending impact of a particle. The structure will be controlled through an algorithm that will utilize piezoelectric devices to activate them in unison with the bistable laminate to successfully deter. A novel experimental setup will be constructed to ensure that the bistable laminate stays fixed when acting as a mechanical deterrent. Piezoelectricity is the main driving force of the bistable laminate to morph and this study will use a Macro Fiber Composite (MFC) actuator that contains piezoelectric ceramic rods in a patch to transfer electrical …

Go to article

High Throughput And Highly Controllable Methods For In Vitro Intracellular Delivery, Justin Brooks, Grayson Minnick, Prithvijit Mukherjee, Arian Jaberi, Lingqian Chang, Horacio D. Espinosa, Ruiguo Yang Dec 2022

High Throughput And Highly Controllable Methods For In Vitro Intracellular Delivery, Justin Brooks, Grayson Minnick, Prithvijit Mukherjee, Arian Jaberi, Lingqian Chang, Horacio D. Espinosa, Ruiguo Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In vitro and ex vivo intracellular delivery methods hold the key for releasing the full potential of tissue engineering, drug development, and many other applications. In recent years, there has been significant progress in the design and implementation of intracellular delivery systems capable of delivery at the same scale as viral transfection and bulk electroporation but offering fewer adverse outcomes. This review strives to examine a variety of methods for in vitro and ex vivo intracellular delivery such as flow-through microfluidics, engineered substrates, and automated probe-based systems from the perspective of throughput and control. Special attention is paid to a …

Go to article

Hierarchical Structure And Material Integration For Electrocatalytic Co2 Reduction, Hamed Mehrabi Dec 2022

Hierarchical Structure And Material Integration For Electrocatalytic Co2 Reduction, Hamed Mehrabi

Graduate Theses and Dissertations

CO2 released by the combustion of fossil fuels is driving significant changes to the earth’sclimate. The natural cycle for removing CO2 from the atmosphere, namely photosynthesis, cannot keep up with the rate at which it is being added. Developing engineering approaches to remove CO2 from the atmosphere is becoming essential to reduce these effects. Removal leads to further issues of carbon sequestration and favorable CO2 reuse strategies, including the electrochemical transformation of recovered CO2 to useful products such as fuels and materials. Copper is an important electrocatalyst for the CO2 reduction reaction (CO2RR) because of its unique capability for producing …

Go to article

Towards The Electronic Response Of Carbon-Based Van Der Waals Heterostructures In A Diamond Anvil Cell, George Thomas Foskaris Dec 2022

Towards The Electronic Response Of Carbon-Based Van Der Waals Heterostructures In A Diamond Anvil Cell, George Thomas Foskaris

UNLV Theses, Dissertations, Professional Papers, and Capstones

The nanoscale regime of materials has been at the forefront of research and interest in condensed matter physics for many years. In a merger of the fields of two-dimensional (2D) materials and high pressure physics, we present an investigation of the electronic response of carbon-based, van der Waals (vdW) heterostructures in a diamond anvil cell (DAC). Combining these fields presents us with the ability to study the characteristics of such systems both optically, and through electrical transport. Properties such as conductance, band structure, and layer number are considered. The samples in this study are assembled using exfoliation and stacking techniques …

Go to article

Dynamic Perimeter Movement Using Uavs And Robotic Systems, Nayeli Barrett, John Lawson, Billy Kihei Nov 2022

Dynamic Perimeter Movement Using Uavs And Robotic Systems, Nayeli Barrett, John Lawson, Billy Kihei

Symposium of Student Scholars

For this study, we propose a Dynamic Perimeter Movement system that has a user-operated UAV to identify GPS coordinate points using land markers such as April Tags. These markers would be used to identify the perimeter of a road work zone. Once the work zone is determined, autonomous robotic traffic cones would disperse to position themselves around the perimeter determined by coordinate points. As the work zone progresses the UAV would periodically update the perimeter to reposition robotic traffic cones. These traffic cones will operate using a Pure Pursuit system as a means to navigate.

Go to article

Backpack Effects On Two-Dimensional Gait Spatiotemporal And Kinematic Parameters, Nardo Rizaldy, Alvin Alvin, Wirawan Lingga, Ethan B.W. Goeij, F. Ferryanto Nov 2022

Backpack Effects On Two-Dimensional Gait Spatiotemporal And Kinematic Parameters, Nardo Rizaldy, Alvin Alvin, Wirawan Lingga, Ethan B.W. Goeij, F. Ferryanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Loads could affect the body gait in various ways. Backpacks, sling bags, suitcases, and even trolleys could hugely affect human gait without us realizing it. The effects of these loads have been scientifically researched in biomechanics and sports science for the past few years. For instance, the comparison of walking with and without a backpack could easily reveal significant differences in body segments, which could be utilized for therapy and medicine development. The aim of this research is to determine the differences of the spatiotemporal kinematic parameters between a conventional human gait and a backpackloaded gait. Some parameters to be …

Go to article

Investigate The Potential Renewable Energy Of Microalgae Spirulina Sp Using Proximate Analyzer, Sem-Edx, And Thermogravimetry, Yahya Zakaria, Sukarni Sukarni, Poppy Puspitasari, Nandang Mufti, Samsudin Anis, Anwar Johari Nov 2022

Investigate The Potential Renewable Energy Of Microalgae Spirulina Sp Using Proximate Analyzer, Sem-Edx, And Thermogravimetry, Yahya Zakaria, Sukarni Sukarni, Poppy Puspitasari, Nandang Mufti, Samsudin Anis, Anwar Johari

Journal of Mechanical Engineering Science and Technology (JMEST)

Microalgae Spirulina sp which has been cultivated by the Brackishwater Aquaculture Development Center, Situbondo Indonesia were tested for their potential energy performance using proximate analyzer, SEMEDX, and thermogravimetry. The proximate analyzer showed volatile matter (VM), fixed carbon (FC), moisture, ash content (AC), total sulfur of microalgae Spirulina sp 68.15, 12.57, 11.22, 8.06, and 0.67 (wt%, ar), respectively, and the gross calorific value (GCV) is 4971 kcal/kg (dry basis). SEM-EDX test showed the morphology and chemical content of Spirulina sp. The content of microalgae Spirulina sp is dominated by carbon (C) and oxygen (O), then followed by chlorine (Cl), sodium (Na), …

Go to article

The Effect Of Nozzle Temperature, Infill Geometry, Layer Height And Fan Speed On Roughness Surface In Petg Filament, Doohan Taqdissillah, Aris Zainul Mutaqqin, Mahros Darsin, Dedi Dwilaksana, Nasrul Ilminnafik Nov 2022

The Effect Of Nozzle Temperature, Infill Geometry, Layer Height And Fan Speed On Roughness Surface In Petg Filament, Doohan Taqdissillah, Aris Zainul Mutaqqin, Mahros Darsin, Dedi Dwilaksana, Nasrul Ilminnafik

Journal of Mechanical Engineering Science and Technology (JMEST)

3D printing is a process of making three-dimensional solid objects from a digital file process created by laying down successive layers of material until the object is created. Many filaments can be used in 3D printing, one of which is PETG (PolyEthylene Terephthalate Glycol). PETG is a modification of PET (PolyEthylene Terephthalate) with added glycol at a molecular level to offer different chemical properties that provide significant chemical resistance, durability, and excellent formability for manufacturing. This study aims to find the most optimal parameter of surface roughness of PETG with different parameters of nozzle temperature, infill geometry, layer height and …

Go to article

Study On Predictive Maintenance Of V-Belt In Milling Machines Using Machine Learning, Reza Aulia Rahman, Mohammad Faishol Erikyatna, Achmad Fauzan Hery Soegiharto Nov 2022

Study On Predictive Maintenance Of V-Belt In Milling Machines Using Machine Learning, Reza Aulia Rahman, Mohammad Faishol Erikyatna, Achmad Fauzan Hery Soegiharto

Journal of Mechanical Engineering Science and Technology (JMEST)

Towards industry 4.0, monitoring the degradation of machine tools’ components becomes a key feature so that smooth productivity is achieved. To preserve the functionality and performance of the machine tools, proper maintenance activities must be planned and carried out. V-belt is important component in machine tools that transmits power from the electric motor spindle in order to machine to work and cut desired material properly. The purpose of this research is to develop a predictive maintenance system for v-belt milling machine Krisbow 31N2F using machine learning. The machine learning algorithm models using multiple and simple linear regression algorithm was developed …

Go to article

True Stress-Strain Behavior Of Al-Based Cast Automotive Alloy Under Different Ageing Conditions And The Effect Of Trace Zr, Mashiur Rahman Shoummo, Akib Abdullah Khan, Mohammad Salim Kaiser Nov 2022

True Stress-Strain Behavior Of Al-Based Cast Automotive Alloy Under Different Ageing Conditions And The Effect Of Trace Zr, Mashiur Rahman Shoummo, Akib Abdullah Khan, Mohammad Salim Kaiser

Journal of Mechanical Engineering Science and Technology (JMEST)

A thorough investigation has been carried out on the Al-12Si-1Mg-1Cu-1Ni automotive alloy considering different properties, specially mechanical properties associated with true stress and true strain with Zr addition of trace amount. A commercially available piston is melted to produce the alloy, and trace amount of Zr is added to make another. The base alloy along with the Zr added alloy had been applied to homogenization, solution treatment, quenching, and ageing in order to get the age-hardening response. The alloys have been heat-treated at 25 ºC, 200 ºC, and 300 ºC, respectively, for four hours for attaining the under, peak and …

Go to article

Effect Of Graphene Addition On Bacterial Cellulose-Based Nanocomposite, Jibril Maulana, Heru Suryanto, Aminnudin Aminnudin Nov 2022

Effect Of Graphene Addition On Bacterial Cellulose-Based Nanocomposite, Jibril Maulana, Heru Suryanto, Aminnudin Aminnudin

Journal of Mechanical Engineering Science and Technology (JMEST)

Bacterial cellulose (BC) is a widespread, low-cost biopolymer that has generally been produced from plants and biomass waste. A method for improving the range of applications for bacterial cellulose is adding graphene material. It has an outstanding feature that can increase the performance of nanocomposite materials. The research aims to observe the effect of graphene on the surface morphology, crystallinity, chemical bonding, and tensile strength of BC/CuO nanocomposite. For this study's synthesis, BC was synthesized by fermenting pineapple peel extract for 10 to 14 days. The produced BC was crushed, homogenized with a nano homogenizer machine, and filtered. Filtered BC, …

Go to article

Efects Of Non‑Newtonian Viscosity On Arterial And Venous Fow And Transport, Sabrina Lynch, Nitesh Nama, C Alberto Figueroa Nov 2022

Efects Of Non‑Newtonian Viscosity On Arterial And Venous Fow And Transport, Sabrina Lynch, Nitesh Nama, C Alberto Figueroa

Department of Mechanical and Materials Engineering: Faculty Publications

It is well known that blood exhibits non-Newtonian viscosity, but it is generally modeled as a Newtonian fluid. However, in situations of low shear rate, the validity of the Newtonian assumption is questionable. In this study, we investigated differences between Newtonian and non-Newtonian hemodynamic metrics such as velocity, vorticity, and wall shear stress. In addition, we investigated cardiovascular transport using two different approaches, Eulerian mass transport and Lagrangian particle tracking. Non-Newtonian solutions revealed important differences in both hemodynamic and transport metrics relative to the Newtonian model. Most notably for the hemodynamic metrics, in-plane velocity and vorticity were consistently larger in …

Go to article

Efficient Interface Enabled By Nano-Hydroxyapatite@Porous Carbon For Lithium-Sulfur Batteries, Jia-Yu Wang, Xue-Feng Tong, Qi-Fan Peng, Yue-Peng Guan, Wei-Kun Wang, An-Bang Wang, Nai-Qiang Liu, Ya-Qin Huang Nov 2022

Efficient Interface Enabled By Nano-Hydroxyapatite@Porous Carbon For Lithium-Sulfur Batteries, Jia-Yu Wang, Xue-Feng Tong, Qi-Fan Peng, Yue-Peng Guan, Wei-Kun Wang, An-Bang Wang, Nai-Qiang Liu, Ya-Qin Huang

Journal of Electrochemistry

The dissolution and “shuttle effect” of lithium polysulfides (LiPSs) hinder the application of lithium-sulfur (Li-S) batteries. To solve those problems, inspired by natural materials, a nano-hydroxyapatite@porous carbon derived from chicken cartilage (nano-HA@CCPC) was fabricated by employing a simple pre-carbonization and carbonization method, and applied in Li-S batteries. The nano-HA@CCPC would provide a reactive interface that allows efficient LiPSs reduction. With a strong affinity for LiPSs and an excellent electronic conductive path for converting LiPSs, the shuttle effect of LiPSs was confined and the redox kinetics of LiPSs was substantially enhanced. Li-S batteries employing nano-HA@CCPC-modified separators exhibited long cycle life and …

Go to article

Which Factor Dominates Battery Performance: Metal Ion Solvation Structure-Derived Interfacial Behavior Or Solid Electrolyte Interphase Layer?, Hao-Ran Cheng, Zheng Ma, Ying-Jun Guo, Chun-Sheng Sun, Qian Li, Jun Ming Nov 2022

Which Factor Dominates Battery Performance: Metal Ion Solvation Structure-Derived Interfacial Behavior Or Solid Electrolyte Interphase Layer?, Hao-Ran Cheng, Zheng Ma, Ying-Jun Guo, Chun-Sheng Sun, Qian Li, Jun Ming

Journal of Electrochemistry

Solid-electrolyte interphase (SEI) layer formed on the electrode by electrolyte decomposition has been considered to be one of the most important factors affecting the battery performance. We discover that the metal ion solvation structure can also influence the performance, particularly, it can elucidate many phenomena that the SEI cannot. In this review, we summarize the importance of the metal ion solvation structure and the derived metal ion de-solvation behaviors, by which we can build an interfacial model to show the relationship between the interfacial behavior and electrode performance, and then apply to different electrode and battery systems. We emphasize the …

Go to article

Advances And Atomistic Insights Of Electrolytes For Lithium-Ion Batteries And Beyond, Tingzheng Hou, Xiang Chen, Lu Jiang, Cheng Tang Nov 2022

Advances And Atomistic Insights Of Electrolytes For Lithium-Ion Batteries And Beyond, Tingzheng Hou, Xiang Chen, Lu Jiang, Cheng Tang

Journal of Electrochemistry

Electrolytes and the associated electrode-electrolyte interfaces are crucial for the development and application of high-capacity energy storage systems. Specifically, a variety of electrolyte properties, ranging from mechanical (compressibility, viscosity), thermal (heat conductivity and capacity), to chemical (solubility, activity, reactivity), transport, and electrochemical (interfacial and interphasial), are correlated to the performance of the resultant full energy storage device. In order to facilitate the operation of novel electrode materials, extensive experimental efforts have been devoted to improving these electrolyte properties by tuning the physical design and/or chemical composition. Meanwhile, the recent development of theoretical modeling methods is providing atomistic understandings of the …

Go to article

Review On Oxygen-Free Vanadium-Based Cathodes For Aqueous Zinc-Ion Batteries, Xiao-Ru Yun, Yu-Fang Chen, Pei-Tao Xiao, Chun-Man Zheng Nov 2022

Review On Oxygen-Free Vanadium-Based Cathodes For Aqueous Zinc-Ion Batteries, Xiao-Ru Yun, Yu-Fang Chen, Pei-Tao Xiao, Chun-Man Zheng

Journal of Electrochemistry

Aqueous zinc-ion batteries (AZIBs) are considered as one of the most promising next-generation electrochemical energy storage systems owing to their high-power density, environmental benign, intrinsic safety, and the low cost of the abundant zinc resources. However, their further development is still plagued by the inferior electrochemical performance of cathode materials. Though extensive research has been conducted to investigate various cathode materials (including manganese oxides, vanadium oxides, Prussian blues analogy, and organic materials), design of high-performance cathodes with satisfying capacity and long-term cycling stability still faces great challenges. Oxygen-free vanadium-based compounds, owing to their better conductivity, larger interlayer spacing, lower ion …

Go to article

Insight Into The Effects Of Cation Disorder And Surface Chemical Residues On The Initial Coulombic Efficiency Of Layered Oxide Cathode, Jin-Li Liu, Han-Feng Wu, Zhi-Bei Liu, Ying-Qiang Wu, Li Wang, Feng-Li Bei, Xiang-Ming He Nov 2022

Insight Into The Effects Of Cation Disorder And Surface Chemical Residues On The Initial Coulombic Efficiency Of Layered Oxide Cathode, Jin-Li Liu, Han-Feng Wu, Zhi-Bei Liu, Ying-Qiang Wu, Li Wang, Feng-Li Bei, Xiang-Ming He

Journal of Electrochemistry

Lithium layered oxide LiNi0.6Co0.2Mn0.2O2 (NCM622) is one of the most promising cathode materials in high-energy lithium-ion batteries for electric vehicles. However, one drawback for NCM622 is that its initial coulombic efficiency (ICE) is only about 87%, which is at least 6% lower than that of LiCoO2 or LiFePO4. In this work, we investigated the effects of surface chemical residues (e.g., LiOH and Li2CO3) and Li/Ni cation disorder resulted during the sintering on the ICE. We found that the ICE of the as-prepared samples could be boosted …

Go to article

Enhanced Electron Correlation And Significantly Suppressed Thermal Conductivity In Dirac Nodal-Line Metal Nanowires By Chemical Doping, Amanda L. Coughlin, Zhiliang Pan, Jeonghoon Hong, Tongxie Zhang, Xun Zhan, Wenqian Wu, Dongyue Xie, Tian Tong, Thomas Ruch, Jean J. Heremans, Jiming Bao, Herbert A. Fertig, Jian Wang, Jeongwoo Kim, Hanyu Zhu, Deyu Li, Shixiong Zhang Nov 2022

Enhanced Electron Correlation And Significantly Suppressed Thermal Conductivity In Dirac Nodal-Line Metal Nanowires By Chemical Doping, Amanda L. Coughlin, Zhiliang Pan, Jeonghoon Hong, Tongxie Zhang, Xun Zhan, Wenqian Wu, Dongyue Xie, Tian Tong, Thomas Ruch, Jean J. Heremans, Jiming Bao, Herbert A. Fertig, Jian Wang, Jeongwoo Kim, Hanyu Zhu, Deyu Li, Shixiong Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

Enhancing electron correlation in a weakly interacting topological system has great potential to promote correlated topological states of matter with extraordinary quantum properties. Here, the enhancement of electron correlation in a prototypical topological metal, namely iridium dioxide (IrO2), via doping with 3d transition metal vanadium is demonstrated. Single-crystalline vanadium-doped IrO2 nanowires are synthesized through chemical vapor deposition where the nanowire yield and morphology are improved by creating rough surfaces on substrates. Vanadium doping leads to a dramatic decrease in Raman intensity without notable peak broadening, signifying the enhancement of electron correlation. The enhanced electron correlation is further …

Go to article

Exosomes Derived From Differentiated Human Admsc With The Schwann Cell Phenotype Modulate Peripheral Nerve-Related Cellular Functions, Bo Liu, Yunfan Kong, Wen Shi, Mitchell Kuss, Ke Liao, Guoku Hu, Peng Xiao, Jagadesan Sankarasubramanian, Chittibabu Guda, Xinglong Wang, Yuguo Lei, Bin Duan Nov 2022

Exosomes Derived From Differentiated Human Admsc With The Schwann Cell Phenotype Modulate Peripheral Nerve-Related Cellular Functions, Bo Liu, Yunfan Kong, Wen Shi, Mitchell Kuss, Ke Liao, Guoku Hu, Peng Xiao, Jagadesan Sankarasubramanian, Chittibabu Guda, Xinglong Wang, Yuguo Lei, Bin Duan

Department of Mechanical and Materials Engineering: Faculty Publications

Peripheral nerve regeneration remains a significant clinical challenge due to the unsatisfactory functional recovery and public health burden. Exosomes, especially those derived from mesenchymal stem cells (MSCs), are promising as potential cell-free therapeutics and gene therapy vehicles for promoting neural regeneration. In this study, we reported the differentiation of human adipose derived MSCs (hADMSCs) towards the Schwann cell (SC) phenotype (hADMSC-SCs) and then isolated exosomes from hADMSCs with and without differentiation (i.e., dExo vs uExo). We assessed and compared the effects of uExo and dExo on antioxidative, angiogenic, antiinflammatory, and axon growth promoting properties by using various peripheral nerve-related cells. …

Go to article

Designing And Cnc Machine Valve Sub-Plates And Quick Mounts For Hydraulic Power Training Systems, Connor Maxam Nov 2022

Designing And Cnc Machine Valve Sub-Plates And Quick Mounts For Hydraulic Power Training Systems, Connor Maxam

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Business and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Connor Maxam on November 22, 2022.

Go to article

Phase Space Analysis Of Nonlinear Wave Propagation In A Bistable Mechanical Metamaterial With A Defect, Mohammed A. Mohammed, Piyush Grover Nov 2022

Phase Space Analysis Of Nonlinear Wave Propagation In A Bistable Mechanical Metamaterial With A Defect, Mohammed A. Mohammed, Piyush Grover

Department of Mechanical and Materials Engineering: Faculty Publications

We study the dynamics of solitary waves traveling in a one-dimensional chain of bistable elements in the presence of a local inhomogeneity (“defect”). Numerical simulations reveal that depending upon its initial speed, an incoming solitary wave can get transmitted, captured, or reflected upon interaction with the defect. The dynamics are dominated by energy exchange between the wave and a breather mode localized at the defect. We derive a reduced-order two degree of freedom Hamiltonian model for wave-breather interaction and analyze it using dynamical systems techniques. Lobe dynamics analysis reveals the fine structure of phase space that leads to the complicated …

Go to article

Feedforward Control Of Thermal History In Laser Powder Bed Fusion: Toward Physics-Based Optimization Of Processing Parameters, Alex Riensche, Benjamin D. Bevans, Ziyad M. Smoqi, Reza Yavari, Ajay Krishnan, Josie Gilligan, Nicholas Piercy, Kevin D. Cole, Prahalada K. Rao Nov 2022

Feedforward Control Of Thermal History In Laser Powder Bed Fusion: Toward Physics-Based Optimization Of Processing Parameters, Alex Riensche, Benjamin D. Bevans, Ziyad M. Smoqi, Reza Yavari, Ajay Krishnan, Josie Gilligan, Nicholas Piercy, Kevin D. Cole, Prahalada K. Rao

Department of Mechanical and Materials Engineering: Faculty Publications

We developed and applied a model-driven feedforward control approach to mitigate thermal-induced flaw formation in laser powder bed fusion (LPBF) additive manufacturing process. The key idea was to avert heat buildup in a LPBF part before it is printed by adapting process parameters layer-by-layer based on insights from a physics-based thermal simulation model. The motivation being to replace cumbersome empirical build-and-test parameter optimization with a physics-guided strategy. The approach consisted of three steps: prediction, analysis, and correction. First, the temperature distribution of a part was predicted rapidly using a graph theory-based computational thermal model. Second, the model-derived thermal trends were …

Go to article

Adiabatic Shear Banding In Nickel And Nickel-Based Superalloys: A Review, Russell A. Rowe, Paul G. Allison, Anthony N. Palazotto, Keivan Davami Nov 2022

Adiabatic Shear Banding In Nickel And Nickel-Based Superalloys: A Review, Russell A. Rowe, Paul G. Allison, Anthony N. Palazotto, Keivan Davami

Faculty Publications

This review paper discusses the formation and propagation of adiabatic shear bands in nickel-based superalloys. The formation of adiabatic shear bands (ASBs) is a unique dynamic phenomenon that typically precedes catastrophic, unpredicted failure in many metals under impact or ballistic loading. ASBs are thin regions that undergo substantial plastic shear strain and material softening due to the thermo-mechanical instability induced by the competitive work hardening and thermal softening processes. Dynamic recrystallization of the material’s microstructure in the shear region can occur and encourages shear localization and the formation of ASBs. Phase transformations are also often seen in ASBs of ferrous …

Go to article

The Design And Manufacturing Of An Environmental Chamber To Test Microelectronic Devices, William Graber, Aniket Roy Chowdhury Nov 2022

The Design And Manufacturing Of An Environmental Chamber To Test Microelectronic Devices, William Graber, Aniket Roy Chowdhury

The Journal of Purdue Undergraduate Research

No abstract provided.

Go to article

A Method Of Assessing Peripheral Stent Abrasiveness Under Cyclic Deformations Experienced During Limb Movement, Courtney Keiser, Kaspars Maleckis, Pauline Struczewska, Majid Jadidi, Jason N. Mactaggart, Alexey Kamenskiy Nov 2022

A Method Of Assessing Peripheral Stent Abrasiveness Under Cyclic Deformations Experienced During Limb Movement, Courtney Keiser, Kaspars Maleckis, Pauline Struczewska, Majid Jadidi, Jason N. Mactaggart, Alexey Kamenskiy

Department of Mechanical and Materials Engineering: Faculty Publications

Poor outcomes of peripheral arterial disease stenting are often attributed to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our goals were to develop a method of assessing the abrasiveness of peripheral nitinol stents and apply it to several commercial devices. Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera stents were deployed inside electrospun nanofibrillar tubes with femoropopliteal artery-mimicking mechanical properties and subjected to cyclic axial compression …

Go to article

Multi-Robot Symbolic Task And Motion Planning Leveraging Human Trust Models: Theory And Applications, Huanfei Zheng Nov 2022

Multi-Robot Symbolic Task And Motion Planning Leveraging Human Trust Models: Theory And Applications, Huanfei Zheng

All Dissertations

Multi-robot systems (MRS) can accomplish more complex tasks with two or more robots and have produced a broad set of applications. The presence of a human operator in an MRS can guarantee the safety of the task performing, but the human operators can be subject to heavier stress and cognitive workload in collaboration with the MRS than the single robot. It is significant for the MRS to have the provable correct task and motion planning solution for a complex task. That can reduce the human workload during supervising the task and improve the reliability of human-MRS collaboration. This dissertation relies …

Go to article

Revealing The Pulse-Induced Electroplasticity By Decoupling Electron Wind Force, Xing Li, Qi Zhu, Youran Hong, He Zheng, Jian Wang, Jiangwei Wang, Ze Zhang Oct 2022

Revealing The Pulse-Induced Electroplasticity By Decoupling Electron Wind Force, Xing Li, Qi Zhu, Youran Hong, He Zheng, Jian Wang, Jiangwei Wang, Ze Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

Micro/nano electromechanical systems and nanodevices often suffer from degradation under electrical pulse. However, the origin of pulse-induced degradation remains an open question. Herein, we investigate the defect dynamics in Au nanocrystals under pulse conditions. By decoupling the electron wind force via a properly-designed in situ TEM electropulsing experiment, we reveal a non-directional migration of Σ3{112} incoherent twin boundary upon electropulsing, in contrast to the expected directional migration under electron wind force. Quantitative analyses demonstrate that such exceptional incoherent twin boundary migration is governed by the electron-dislocation interaction that enhances the atom vibration at dislocation cores, rather than driven by the …

Go to article

Electrochemical Syntheses Of Nanomaterials And Small Molecules For Electrolytic Hydrogen Production, Jia-Qi Wei, Xiao-Dong Chen, Shu-Zhou Li Oct 2022

Electrochemical Syntheses Of Nanomaterials And Small Molecules For Electrolytic Hydrogen Production, Jia-Qi Wei, Xiao-Dong Chen, Shu-Zhou Li

Journal of Electrochemistry

Hydrogen is a clean, efficient, renewable energy resource and the most promising alternative to fossil fuels for future carbon-neutral energy supply. Therefore, sustainable hydrogen production is highly attractive and urgently demanded, especially via water electrolysis that has clean, abundant precursors and zero emission. However, current water electrolysis is hindered by the sluggish kinetics and low cost/energy efficiency of both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this regard, electrochemical synthesis offers prospects to raise the efficiency and benefit of water electrolysis by fabricating advanced electrocatalysts and providing more efficient/value-adding co-electrolysis alternatives. It is an eco-friendly and facile …

Go to article

First Prev Next Last