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Articles 4801 - 4830 of 16388

Full-Text Articles in Materials Science and Engineering

Material Analysis Of 3d Welded 5356 Aluminum Alloy, Ryan Fouts Jan 2021

Material Analysis Of 3d Welded 5356 Aluminum Alloy, Ryan Fouts

Electronic Theses and Dissertations

Metal 3D printing has been reserved for aerospace and high-end automotive industries because of its cost. A gas metal arc welder (GMAW) on a rugged 3D printer frame could make metal additive manufacturing an option for more industries and consumers. 3D welded aluminum has not been examined in depth as an option for additive manufacturing (AM). Extensive tests are necessary to determine the correct settings to use a metal inert gas (MIG) welder for AM. Porosity within the welded material must be evaluated to better understand the additive process. The material properties of 3D welded aluminum will be tested and …


Monitoring Of Overhead Polymer Core Composite Conductors Under Excessive Mechanical Loads Using Fiber Bragg Grating Sensors, Daniel H. Waters Jan 2021

Monitoring Of Overhead Polymer Core Composite Conductors Under Excessive Mechanical Loads Using Fiber Bragg Grating Sensors, Daniel H. Waters

Electronic Theses and Dissertations

This combined experimental and numerical study addresses mechanical effects associated with static and dynamic loading of novel High Temperature Low Sag (HTLS) transmission line polymer core composite conductors. The developed methodology was successfully applied to ACCC® to explain the complex failure mechanisms associated with combined bending and tension loading. Furthermore, the use of Fiber Bragg Grating (FBG) sensors was investigated for the first time to monitor the ACCC® design during installation and in-service.

Transverse low-velocity impacts to the ACCC® conductor having either free or constrained end conditions and large axial tensile loads were performed. It was identified that the most …


Hydraulic Balsa Wood Rising Bridge, Kaitlyn Greenfield Jan 2021

Hydraulic Balsa Wood Rising Bridge, Kaitlyn Greenfield

All Undergraduate Projects

What is the solution to allowing tall vessels to navigate past a vehicle bridge that is less than 10 [ft] above the water? To answer this question, a balsa wood bridge was designed, constructed, and tested. The bridge needed to articulate by mechanical means, allow for travel through the bridge, and be able to withstand ample force while the main structure only being constructed of balsa wood and glue. The project was analyzed in sections. These sections include: the bridge structure and its members, the hydraulic lift, and the pins needed for the bridge and hydraulic lift to operate. The …


Molecular To Macroscopic Understanding Of Chloroaluminate Anion Intercalation In Rechargeable Aluminum-Graphite Batteries, Jeffrey Xu Jan 2021

Molecular To Macroscopic Understanding Of Chloroaluminate Anion Intercalation In Rechargeable Aluminum-Graphite Batteries, Jeffrey Xu

Dissertations and Theses

Today’s global energy challenges pose an urgent need to electrify transportation and better store intermittent renewable energy sources (e.g., solar and wind energy). For such large-scale battery applications, aluminum batteries are a promising “beyond lithium-ion” technology due to the high volumetric capacity, earth abundance, low-cost, and inherent safety of aluminum metal. However, there are very few compatible positive electrode materials that exhibit high energy density and cycling stability, in part due to the challenges of electrochemically intercalating highly charged Al3+ cations. Recently, graphite has been demonstrated as a promising positive electrode material in non-aqueous rechargeable aluminum batteries, which store …


Development Of Light Actuated Chemical Delivery Platform On A 2-D Array Of Micropore Structure, Hojjat Rostami Azmand, Hojjat Rostami Azmand Jan 2021

Development Of Light Actuated Chemical Delivery Platform On A 2-D Array Of Micropore Structure, Hojjat Rostami Azmand, Hojjat Rostami Azmand

Dissertations and Theses

Localized chemical delivery plays an essential role in the fundamental information transfers within biological systems. Thus, the ability to mimic the natural chemical signal modulation would provide significant contributions to understand the functional signaling pathway of biological cells and develop new prosthetic devices for neurological disorders. In this paper, we demonstrate a light-controlled hydrogel platform that can be used for localized chemical delivery in a high spatial resolution. By utilizing the photothermal behavior of graphene-hydrogel composites confined within micron-sized fluidic channels, patterned light illumination creates the parallel and independent actuation of chemical release in a group of fluidic ports. The …


Atomic-Scale Simulation Of Dissipation And Adhesion During Interactions Between Mineral Surfaces, Baochi Doan Jan 2021

Atomic-Scale Simulation Of Dissipation And Adhesion During Interactions Between Mineral Surfaces, Baochi Doan

Electronic Theses and Dissertations, 2020-2023

Adhesion and dissipation during surface interactions are important phenomena with wide applications in materials science, including cold-spray technology for additive manufacturing and stiction in MEMS (Mircro ElectroMechanical Systems). In planet formation theories, energy dissipation in collisions between mineral grains is important to the formation of dust-grain aggregates and planetesimals. Early contact mechanics theories such as Hertz and Johnson-Kendall-Roberts have laid theoretical foundations for understanding these phenomena. Recently, there are breakthroughs in using non-equilibrium thermodynamics methods to elucidate dissipation. For example, the Green-Kubo method can calculate transport coefficients based on the Fluctuation-Dissipation theorem, and Jarzynski equality can be used to determine …


Processing Of 3d Porous Biomaterial Scaffolds To Enhance The In Vitro Breast Cancer Tumor Microenvironment, Zi Wang Jan 2021

Processing Of 3d Porous Biomaterial Scaffolds To Enhance The In Vitro Breast Cancer Tumor Microenvironment, Zi Wang

Electronic Theses and Dissertations, 2020-2023

Tumors contain heterogeneous cell populations within the tumor microenvironment (TME). TME supports tumor progression and development via the function of multiple cell types and cell-extracellular matrix (ECM) interactions. 3D porous biomaterial scaffolds can be a type of in vitro tumor models to mimic TME ECM. Current tumor models lack structural complexity replicating tumor ECM, tunable mechanical properties, and have limited mass exchange between cells and their microenvironment. In this work, we firstly developed scaffolds with a hierarchical pore structure via the Freeze-FRESH(FF) fabrication technique that combines 3D printing and freeze-casting. Later, we studied the effect of varying processing parameters and …


Microstructural Development Of Inconel 625 Nickel-Based Superalloy As Function Of Laser Powder Bed Fusion Parameters, Sofia Nucci Jan 2021

Microstructural Development Of Inconel 625 Nickel-Based Superalloy As Function Of Laser Powder Bed Fusion Parameters, Sofia Nucci

Electronic Theses and Dissertations, 2020-2023

Additive manufacturing (AM) allows fabrication of complex components with features that are impractical or impossible to achieve through conventional methods. Selective laser melting (SLM) powder bed fusion AM technology was selected for this study on Inconel 625, a widely utilized high-temperature alloy that is hard to machine. The present work investigates impact of laser power and scanning speed variations on the resulting characteristics of fabricated IN625 samples. Gas atomized metallic alloy powders were acquired and analyzed through laser diffraction to verify acceptable size distribution. Cubic samples were built with a range of laser scan speeds in 200 mm/s intervals for …


Lightning Strike Response Of Composite Structures: A Review, Akhileshwar Pandey, Ashutosh Kumar Upadhyay, Karunesh Kumar Shukla Jan 2021

Lightning Strike Response Of Composite Structures: A Review, Akhileshwar Pandey, Ashutosh Kumar Upadhyay, Karunesh Kumar Shukla

Journal of Metals, Materials and Minerals

Wind turbines and aircraft are generally made of less conductive carbon/glass composites. Significant damages may occur to these materials if they are struck by high energy lightning strikes. Damage and structural response of composites is essentially a multiphysics domain, involving thermal, electrical, magnetic and structural analysis. In this article, the fundamental physics of lightning, multiphysics analysis, numerical implementation and experimental studies about composite materials are reviewed. The relevant international standards and possible characterization methods of lightning strike damage are also reproduced in this article. In addition to this, the current and prospective technologies, to protect composite from lightning strikes are …


Wear Behavior Of Aluminium 6061 Alloy Reinforced With Coated/Uncoated Multiwalled Carbon Nanotube And Graphene, Vijee Kumar, Kempaiah Ujjaini Nagegowda, Satish Babu Boppana, Ramesh Sengottuvelu, Palanikumar Kayaroganam Jan 2021

Wear Behavior Of Aluminium 6061 Alloy Reinforced With Coated/Uncoated Multiwalled Carbon Nanotube And Graphene, Vijee Kumar, Kempaiah Ujjaini Nagegowda, Satish Babu Boppana, Ramesh Sengottuvelu, Palanikumar Kayaroganam

Journal of Metals, Materials and Minerals

The current study deals with the fabrication and investigation of wear characteristics of Aluminium 6061(Al6061) hybrid metal matrix composites (MMCs) processed through powder metallurgy technique. Al6061 hybrid MMCs involving fixed 2 wt% of coated/uncoated multiwalled carbon nanotubes (MWCNTs) and varying weight percentages of graphene were fabricated through ball milling procedure. To enhance the scattering of MWCNTs in the matrix, MWCNTs were coated by means of copper through electroless deposition method. Dry sliding wear conduct of Al6061 MMCs was investigated using a pin-on-disc wear testing machine. It was found that at lower load, composites exhibited lower wear resistance than base alloy …


Improvement On Cost-Performance Ratio Of Fiberglass/Carbon Fiber Hybrid Composite, Nathawat Poopakdee, Warut Thammawichai Jan 2021

Improvement On Cost-Performance Ratio Of Fiberglass/Carbon Fiber Hybrid Composite, Nathawat Poopakdee, Warut Thammawichai

Journal of Metals, Materials and Minerals

Fiberglass composite (FG) is widely used as a metal substitute in general applications due to its corrosion and chemical resistance, relatively high strength, and low cost. Still, the FG is deficient in performance and relatively heavy for airframes. Carbon fiber composite (CF) is utilized instead as it has greater performance and lower weight. However, the CF is brittle and expensive. Thus, in this work, we combine FG and CF into two types of hybrid composites to achieve a cost-effective solution with greater or comparable mechanical properties to those of CF. The first one uses FG as core and CF as …


Efficiency Of Tri-N-Octylamine For The Liquid-Liquid Extraction Of Co (Ii) From Acidic Chloride Medium, Aishwarya Mishra, Nilam Swain, Sanghamitra Pradhan, Sujata Mishra Jan 2021

Efficiency Of Tri-N-Octylamine For The Liquid-Liquid Extraction Of Co (Ii) From Acidic Chloride Medium, Aishwarya Mishra, Nilam Swain, Sanghamitra Pradhan, Sujata Mishra

Journal of Metals, Materials and Minerals

Cobalt criticality is increasing as a function of time and this concern has impelled researchers to ascertain efficient recovery schemes of cobalt. In this paper, an extraction strategy for cobalt utilizing tri-n-octyl amine (TOA) in kerosene from acidic chloride media has been developed. The extraction percentage was found to be 76.7 using 1.5M TOA. The extracted species has been formulated as (R3NH) CoCl3 based on the findings of slope analysis. Influence of various salting out agents like NH4Cl, KCl, and NaCl on the percentage extraction has been analysed and KCl emerged as beneficial for extraction. The estimated values of enthalpy …


Gas Pressure And Coating Distance For Nanohydroxyapatite Deposition On Stainless Steel 316l Using Flame Spray Technique, Angga Saputra, Utami Dyah Syafitri, Toto Sudiro, Gerald Ensang Timuda, Yessie Widya Sari Jan 2021

Gas Pressure And Coating Distance For Nanohydroxyapatite Deposition On Stainless Steel 316l Using Flame Spray Technique, Angga Saputra, Utami Dyah Syafitri, Toto Sudiro, Gerald Ensang Timuda, Yessie Widya Sari

Journal of Metals, Materials and Minerals

 Metal implant coating engineering is needed to improve the surface biocompatibility properties of metals.  For this, coating metal surfaces with bioactive and biocompatible biomaterials will be an option. Having high biocompatibility as well as similarity in chemical properties, nanohydroxyapatite may be a candidate as biomaterials for coating the metal implant. The key to the success of metal implant plating is the formation of pores which increase the bioactivity and biocompatibility properties of the implant. In this study, nanohydroxyapatite was used to be coated on stainless steel type 316L (SS316L). To ensure that the coating works properly on the surface, an …


Microstructure And Properties Of Zirconia-Alumina Composites Fabricated Via Powder Injection Molding, Nalattaporn Saelee, Nutthita Chuankrerkkul, Panitarn Wanakamol Jan 2021

Microstructure And Properties Of Zirconia-Alumina Composites Fabricated Via Powder Injection Molding, Nalattaporn Saelee, Nutthita Chuankrerkkul, Panitarn Wanakamol

Journal of Metals, Materials and Minerals

This study aimed to fabricate zirconia-alumina composites via powder injection molding and investigated the effects of alumina addition on microstructure as well as physical properties of the composites. Zirconia-alumina composites were prepared using polyethylene glycol (PEG) and polyvinyl butyral (PVB) as binders.  The powder loading was fixed at 38 vol%, and PEG: PVB binder weight ratio was fixed at 80:20.  Alumina content within ceramic component was varied at 0, 10, 20, 30, 40 and 50 vol% to observe the effect of alumina on the composite structures and properties. The injection molding was done at 190℃ followed by water debinding of …


Analysis Of The Impact Factors From The Friction Stir Welding Process For Dissimilar Butt Joints Between Semi-Solid Cast Aluminum 356 And Aisi 1018 Carbon Steel, Worapong Boonchouytan, Jaknarin Chatthong, Rommador Burapa Jan 2021

Analysis Of The Impact Factors From The Friction Stir Welding Process For Dissimilar Butt Joints Between Semi-Solid Cast Aluminum 356 And Aisi 1018 Carbon Steel, Worapong Boonchouytan, Jaknarin Chatthong, Rommador Burapa

Journal of Metals, Materials and Minerals

This research aimed to study the impacts of three different rotation speeds of 710, 1000, and 1400 rpm and three welding speeds of 40, 56, and 80 mm·min-1, on dissimilar butt joints between semi-solid aluminum 356 and AISI 1018 carbon steel. Welding tools were made from tungsten carbide material, and the offset was 0 mm. It was found that an increase in the rotation speed and welding speed caused accumulated heat, which led to the appropriate changes in the metallurgical structure. The rotation speed and welding speed factors had the impact on the greater blending of the two metals at …


Eco-Friendly Lake Pigment From Sappanwood: Adsorption Study And Its Application As Natural Colorant For Natural Rubber Toy Balloon, Jitnapa Sirirak, Ployphat Suppharatthanya, Kedsarin Chantha, Sutinee Girdthep, Supanee Chayabutra Jan 2021

Eco-Friendly Lake Pigment From Sappanwood: Adsorption Study And Its Application As Natural Colorant For Natural Rubber Toy Balloon, Jitnapa Sirirak, Ployphat Suppharatthanya, Kedsarin Chantha, Sutinee Girdthep, Supanee Chayabutra

Journal of Metals, Materials and Minerals

Due to the awareness of the impact of synthetic dye on human health and the environment, natural dye and lake pigment have attracted considerable attention from researcher. Herein, pink−red lake pigment from sappanwood was prepared using adsorption approach. The effects of initial pH, pH and concentration of brazilein solution, dosage of aluminium hydroxide, and adsorption time on adsorption were also explored. Results showed that the maximum adsorption capacity of 30 mg g-1 was achieved when 0.25%w/v of aluminium hydroxide and 100 mg L-1 of brazilein solution were applied. The adsorption kinetics and adsorption isotherm fitted the pseudo second order model …


Sustainable Valorization Of Sugarcane Leaves For Succinic Acid And Biochar Production, Nuttaporn Chokesawatanakit, Pasakorn Jutakridsada, Khanita Kamwilaisak Jan 2021

Sustainable Valorization Of Sugarcane Leaves For Succinic Acid And Biochar Production, Nuttaporn Chokesawatanakit, Pasakorn Jutakridsada, Khanita Kamwilaisak

Journal of Metals, Materials and Minerals

The leaves of sugarcane (Saccharum officinarum) are agricultural waste that is burnt before harvesting. This project aims to find an alternative way to increase the value of sugarcane leaves and decrease air pollution by using the leaves as raw material to produce succinic acid and biochar. Reducing sugars were extracted from the leaves by H2SO4 hydrolysis. The sugars were then fermented by Yarrowia lipolytica TBRC 4417 to produce succinic acid. The solid residue was used as the raw material for biochar production by pyrolysis. The effects of pyrolysis temperature (350, 400, and 450℃) and nitrogen gas flow rate (5, 10, …


Laser Powder Bed Fusion Of Ti6al4v-Xcu: Process Parameters, Thywill Ccphas Dzogbewu Jan 2021

Laser Powder Bed Fusion Of Ti6al4v-Xcu: Process Parameters, Thywill Ccphas Dzogbewu

Journal of Metals, Materials and Minerals

The original intent of coating biomedical and surgical devices surface with antibacterial agents is to prevent infections. However, the difference in the material properties between the biomedical devices and the coating materials causes the coating material to spall from the biomedical devices. To address the situation, the current research focused on investigating the possibility of using laser powder bed fusion process a subset of additive manufacturing technology to in situ alloy 1 at% Cu with Ti6Al4V. In situ alloying 1 at% Cu with Ti6Al4V would lead to the production of medical and surgical devices with inbuilt antibacterial property. To determine …


Effects Of Annealing Treatment On Microstructure And Hardness In The 28 Wt% Cr Cast Iron With Mo/W Addition, Kittikhun Ruangchai, Ruangdaj Tongsri, John Thomas Harry Pearce, Torranin Chairuangsri, Amporn Wiengmoon Jan 2021

Effects Of Annealing Treatment On Microstructure And Hardness In The 28 Wt% Cr Cast Iron With Mo/W Addition, Kittikhun Ruangchai, Ruangdaj Tongsri, John Thomas Harry Pearce, Torranin Chairuangsri, Amporn Wiengmoon

Journal of Metals, Materials and Minerals

In this study, the effects of annealing on the hardness and microstructure of 28 wt% Cr-2.6 wt% C iron with 1.4 wt% Mo/1 wt% W addition have been investigated. The as-cast samples were heated to 800℃ and held for 4 h followed by slow cooled with a cooling rate of 20℃h-1 to 500℃. Microstructures were characterized by X-ray diffractometry, optical microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Vickers macro-hardness and micro-hardness were measured. It was found that the as-cast microstructure in the hypoeutectic 28 wt% Cr iron without Mo or W addition consisted of primary austenite dendrite, eutectic M7C3 …


Mechanical Properties And Ionic Conductivity Of Biodegradable Materials In Solid Polymer Electrolyte, Fatin Arhana Awang, Mohd Faiz Hassan, Khadijah Hilmun Kamarudin Jan 2021

Mechanical Properties And Ionic Conductivity Of Biodegradable Materials In Solid Polymer Electrolyte, Fatin Arhana Awang, Mohd Faiz Hassan, Khadijah Hilmun Kamarudin

Journal of Metals, Materials and Minerals

No abstract provided.


Development Of Chemically Grafted Multiwall Carbon Nanotube Onto Cellulose Fiber Sheet And Polyurethane Based Resin Composite For An Active Paper, Siripassorn Sukhkhawuttigit, Sarute Ummartyotin, Yingyot Infahsaeng Jan 2021

Development Of Chemically Grafted Multiwall Carbon Nanotube Onto Cellulose Fiber Sheet And Polyurethane Based Resin Composite For An Active Paper, Siripassorn Sukhkhawuttigit, Sarute Ummartyotin, Yingyot Infahsaeng

Journal of Metals, Materials and Minerals

Cellulose fibers (CFs) and carbon nanotubes (CNTs) were successfully developed on polyurethane substrate as a flexible composite paper. With small amount of CNTs, the composite was prepared by a suction filtration method. The existence of CNT additive in cellulose matrix was investigated based on the correlation of mechanical properties, thermal stability, and electrical properties. Although the highly transparent cellulose sheets impregnated with polyurethane were successfully fabricated, the low transmittance was obtained as the increasing of CNT additive. However, the dielectric properties of composite were enhanced with an addition of CNTs in the composite paper. The electrical conductivity was increased from …


Influence Of Cooling Conditions On Microstructure And Mechanical Property Of Sn-0.3ag-0.7cu Lead-Free Solder, Prajak Jattakul, Tavee Madsa, Piyawan Sunasuan, Niwat Mookam Jan 2021

Influence Of Cooling Conditions On Microstructure And Mechanical Property Of Sn-0.3ag-0.7cu Lead-Free Solder, Prajak Jattakul, Tavee Madsa, Piyawan Sunasuan, Niwat Mookam

Journal of Metals, Materials and Minerals

This research has investigated the influence of cooling conditions on the microstructure and mechanical properties i.e., tensile strength and microhardness of Sn-0.3Ag-0.7Cu lead-free solder. In the experiments, casting was performed at 300℃ with comparison between copper and stainless steel molds under slow and fast cooled conditions. X-ray diffractometer confirmed the presence of Cu6Sn5 and Ag3Sn phases in the solder matrix. Lead-free solder solidified under slow cooled conditions exhibited -Sn matrix with larger grain growth as compared to the fast cooled solder. The eutectic area of intermetallic compound (IMC) was found to increase with cooling rate. The tensile strength of slow …


Automated Control System For The Remote-Controlled Torch Positioner, Christopher Ferguson, Anna Abate, Kyle Cramer, Alex Sabitsch, Jacob Stefanko Jan 2021

Automated Control System For The Remote-Controlled Torch Positioner, Christopher Ferguson, Anna Abate, Kyle Cramer, Alex Sabitsch, Jacob Stefanko

Williams Honors College, Honors Research Projects

The goal of this project is to design and implement a controls system for Dr. Morscher’s burner rig. The rig serves to simulate jet turbine conditions and test how materials, specifically ceramic matrix composites, react under high temperatures and stresses. Currently, the location of the torch relies solely on manual adjustments and has no automated control system. The improved design will automatically adjust the torch position based on the desired temperature of the sample being tested, therefore maintaining a steady environment for the sample. The current method of manual adjustments for regulating temperature is a crude solution that does not …


Phase Formation And Thermal Conductivity Of Zirconium Carbide, Yue Zhou Jan 2021

Phase Formation And Thermal Conductivity Of Zirconium Carbide, Yue Zhou

Doctoral Dissertations

“This research focused on the synthesis and phase formation of zirconium carbide with different carbon contents, and lattice thermal conductivity of zirconium carbide with different carbon vacancy, hafnium, and oxygen contents.

Nominally pure phase ZrCx was synthesized by solid-state reaction of zirconium hydride (ZrHs) and carbon black at a temperature as low as 1300°C. The powder synthesized at 1300C was carbon deficient ZrCx . Carbon stoichiometry of the as- synthesized powders increased as the synthesis temperature increased. As the synthesis temperature increase, the oxygen content of ZrCx decreased due to the increasing C site occupancy. Low stoichiometry …


Harrisburg University’S Face Shield Response For Health Care Workers, Matthew A. Walters Jan 2021

Harrisburg University’S Face Shield Response For Health Care Workers, Matthew A. Walters

Experiential Learning Projects

This project was inducted into the Harrisburg University Digital Common's with a submittal event. The recording for this event can be accessed here: Harrisburg University’s Face Shield Response for Health Care Workers Submittal Event Recording

The pandemic has most definitely been a significant factor in how people operate throughout the past few years. The pandemic was first introduced at the end of 2019 and is still a current issue at the end of 2021. Close to the beginning of the pandemic, health care workers had found themselves with a shortage of protective gear to fight against the virus while working …


The Development Of A Holistic Quality Score Using In-Situ Monitoring Of Laser Powder Bed Fusion, Ryan Daigneault Jan 2021

The Development Of A Holistic Quality Score Using In-Situ Monitoring Of Laser Powder Bed Fusion, Ryan Daigneault

College of Graduate Studies: Theses & Dissertations

Additive manufacturing processes allow for a great degree of flexibility in terms of part production. The process is autonomous once the part has started printing in that the operator generally does not need to intervene until the part is finished. One issue that this introduces, however, is an inability to determine part quality during the printing process. Once a part has started printing, the operator must either wait until the part is finished or regularly check on the part during the print to determine the part quality. Using data gathered from multiple sensors, a quality score can be used to …


Detection Of Subsurface, Nanometer-Scale Crystallographic Defects By Nonlinear Light Scattering And Localization, Farbod Shafiei, Tommaso Orzali, Alexey Vert, Mohammad-Ali Miri, Pui Yee Hung, Man Hoi Wong, Andrea Alù, Gennadi Bersuker, Michael C. Downer Jan 2021

Detection Of Subsurface, Nanometer-Scale Crystallographic Defects By Nonlinear Light Scattering And Localization, Farbod Shafiei, Tommaso Orzali, Alexey Vert, Mohammad-Ali Miri, Pui Yee Hung, Man Hoi Wong, Andrea Alù, Gennadi Bersuker, Michael C. Downer

Publications and Research

Heteroepitaxial crystalline films underlie many electronic and optical technologies but are prone to forming defects at their heterointerfaces. Atomic-scale defects such as threading dislocations that propagate into a film impede the flow of charge carriers and light degrading electrical/optical performance of devices. Diagnosis of subsurface defects traditionally requires time-consuming invasive techniques such as cross-sectional transmission electron microscopy. Using III–V films grown on Si, noninvasive, bench-top diagnosis of subsurface defects have been demonstrated by optical second-harmonic scanning probe microscope. A high-contrast pattern is observed of subwavelength “hot spots” caused by scattering and localization of fundamental light by defect scattering sites. Size …


Actin Cytoskeleton Dynamics And Organization Modulated By Macromolecular Crowding, Cation Interaction, And Nanomaterials, Jinho Park Jan 2021

Actin Cytoskeleton Dynamics And Organization Modulated By Macromolecular Crowding, Cation Interaction, And Nanomaterials, Jinho Park

Electronic Theses and Dissertations, 2020-2023

The assembly of actin, the essential cytoskeleton protein, into filaments and bundles/networks is important in various cellular processes including cell movement and morphogenesis. Actin bundle formation occurs in crowded intracellular environments with the aid of actin-crosslinking proteins. The role of actin-crosslinking proteins such as fascin and a-actinin in bundle formation has been investigated, however, how intracellular environments affect actin crosslinker-induced bundle formation is unknown. In the first two parts of this dissertation, we explore the effects of macromolecular crowding and cation interactions on the organization and mechanics of actin crosslinker-induced bundles. To determine how changing environmental conditions modulate actin bundling, …


Mechanical Properties Of Nanomodified Hybrid Gfrp Composite Materials, Micah Rop Kimutai Jan 2021

Mechanical Properties Of Nanomodified Hybrid Gfrp Composite Materials, Micah Rop Kimutai

College of Graduate Studies: Theses & Dissertations

The mechanical behavior of the nanomodified hybrid epoxy matrix was investigated in glass fiber reinforced plastics (GFRP). In this study, five nanocomposites enriched with as received halloysite, nanomer I.28E, HNT-APTES, and the hybrid combinations of the two HNTs with the nanomer I.28E were successfully fabricated. To evaluate the effects and morphological characteristics of the individual fillers and the hybrid configurations on the epoxy resin matrix, TGA, DSC, and DMA were analyzed. To understand the effect of the five configurations on the neat GFRP laminate, mode I interlaminar fracture toughness, tensile, and vibration properties were investigated. Electron microscopy testing techniques were …


Modeling And Optimization Of Process Parameters In Face Milling Of Ti6al4v Alloy Using Taguchi And Grey Relational Analysis, Al Mazedur Rahman, S M Abdur Rob, Anil K. Srivastava Jan 2021

Modeling And Optimization Of Process Parameters In Face Milling Of Ti6al4v Alloy Using Taguchi And Grey Relational Analysis, Al Mazedur Rahman, S M Abdur Rob, Anil K. Srivastava

Manufacturing & Industrial Engineering Faculty Publications

Titanium alloys are extensively used in aerospace, missiles, rockets, naval ships, automotive, medical devices, and even the consumer electronics industry where a high strength to density ratio, lightweight, high corrosion resistance, and resistance to high temperatures are important. The machining of these alloys has always been challenging for manufacturers. This article investigates the combined effect of radial depth, cutting speed and feed rate on cutting forces, tool life, and surface roughness during face milling of Ti6Al4V alloy. This study focuses on the significance of radial depth of cut on cutting force, tool life and surface roughness compared to that of …