Open Source 3d Printers: An Appropriate Technology For Building Low Cost Optics Labs For The Developing Communities,
2017
Michigan Technological University
Open Source 3d Printers: An Appropriate Technology For Building Low Cost Optics Labs For The Developing Communities, Jephias Gwamuri, Joshua M. Pearce
Department of Materials Science and Engineering Publications
The recent introduction of RepRap (self-replicating rapid prototyper) 3-D printers and the resultant open source technological improvements have resulted in affordable 3-D printing, enabling low-cost distributed manufacturing for individuals. This development and others such as the rise of open source-appropriate technology (OSAT) and solar powered 3-D printing are moving 3-D printing from an industry based technology to one that could be used in the developing world for sustainable development. In this paper, we explore some specific technological improvements and how distributed manufacturing with open-source 3-D printing can be used to provide open-source 3-D printable optics components for developing world communities …
Photodynamic Therapy: Agents And Mechanisms,
2017
Washington University in St. Louis
Photodynamic Therapy: Agents And Mechanisms, Rebecca Claire Gilson
McKelvey School of Engineering Graduate Student Theses & Dissertations
Despite enormous efforts, cancer remains a leading cause of morbidity and mortality world-wide. The main challenges currently facing cancer therapy include lack of adequate tumor targeting, failure to treat hypoxic tumor cells, and induction therapy resistant tumors. A solution to these limitations can be found in photodynamic therapy (PDT) which combines light and light activatable compounds, photosensitizers (PSs), to produce cytotoxic reactive oxygen species (ROS) to damage tumor tissue. This creates a spatiotemporal therapeutic effect, where cell damage only occurs at the intersection of the PS and light. PDT can treat tumors through unique mechanisms which reduce induction of tumor …
Hollow And Porous Plasmonic Nanostructures For Highly Efficient Chemical And Biological Sensing,
2017
Washington University in St. Louis
Hollow And Porous Plasmonic Nanostructures For Highly Efficient Chemical And Biological Sensing, Keng-Ku Liu
McKelvey School of Engineering Graduate Student Theses & Dissertations
Localized surface plasmon resonance (LSPR) involves the collective and coherent oscillation of dielectrically confined conduction electrons. The LSPR wavelength of noble metal nanoparticles (such as gold, silver and copper), which falls into the visible and near infrared range of the electromagnetic spectrum, is sensitive to the composition, size, shape, dielectric properties of the surrounding medium, and proximity to other nanostructures (plasmon coupling). Based on the sensitivity of the surface plasmon resonance to the changes in the dielectric properties of the surrounding medium and the enhancement of the electromagnetic (EM) field in proximity of metal nanostructures, two important classes of plasmonic …
Amorphous Boron Nanorod As An Anode Material For Lithium-Ion Batteries At Room Temperature,
2017
Boise State University
Amorphous Boron Nanorod As An Anode Material For Lithium-Ion Batteries At Room Temperature, Changjian Deng, Miu Lun Lau, Riley Parrish, Kassiopeia A. Smith, Hui Xiong
Materials Science and Engineering Faculty Publications and Presentations
We report an amorphous boron nanorod anode material for lithium-ion batteries prepared through smelting non-toxic boron oxide in liquid lithium. Boron in theory can provide capacity as high as 3099 mAh g-1 by alloying with Li to form B4Li5. However, experimental studies of boron anode were rarely reported for room temperature lithium-ion batteries. Among the reported studies the electrochemical activity and cycling performance of bulk crystalline boron anode material are poor at room temperature. In this work, we utilized amorphous nanostructured one-dimensional (1D) boron material aiming at improving the electrochemical reactivity between boron and lithium ions …
General Design Procedures For Airport-Based Solar Photovoltaic Systems,
2017
Michigan Technological University
General Design Procedures For Airport-Based Solar Photovoltaic Systems, Anurag Anurag, Jiemin Zhang, Jephias Gwamuri, Joshua M. Pearce
Department of Materials Science and Engineering Publications
A source of large surface areas for solar photovoltaic (PV) farms that has been largely overlooked in the 13,000 United States of America (U.S.) airports. This paper hopes to enable PV deployments in most airports by providing an approach to overcome the three primary challenges identified by the Federal Aviation Administration (FAA): (1) reflectivity and glare; (2) radar interference; and (3) physical penetration of airspace. First, these challenges and precautions that must be adhered to for safe PV projects deployment at airports are reviewed and summarized. Since one of the core concerns for PV and airport symbiosis is solar panel …
Analysis Of Variable Insensitive Friction Stir Welding Parameters,
2017
University of New Orleans
Analysis Of Variable Insensitive Friction Stir Welding Parameters, Robert L. Marrero Jr
LSU New Orleans Theses and Dissertations
Friction Stir Welding (FSW) was used to perform a Design of Experiment (DOE) to determine the welding parameters effects on yielding consistent mechanical properties across the length of the weld. The travel speed was varied across set forge force and RPM conditions, to find a dataset that will yield consistent mechanical properties independent of the travel speed. Six different welds were completed on two different aluminum panels, the advancing side being Aluminum alloy 2195-T8 at a thickness of .350”, with the retreating side being Aluminum alloy 2219-T851 with a gauge thickness of .360”. A Left-hand Right-hand self-reacting pin tool was …
Investigation Of Build Strategies For A Hybrid Manufacturing Process Progress On Ti-6al-4v,
2017
Missouri University of Science and Technology
Investigation Of Build Strategies For A Hybrid Manufacturing Process Progress On Ti-6al-4v, Lei Yan, Leon Hill, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The various processing parameters of a hybrid manufacturing process, including deposition and machining, is being investigated with a Design of Experiment (DoE). The intent was to explore the effect of different build strategies on the final part’s Vickers hardness, tensile test, fatigue life, and microstructure. From this experiment, the processing parameters can be linked to various mechanical properties. This will lead to the ability to create a combination of deposition and machining parameters, which will result in improved mechanical properties.
Fabricating Zirconia Parts With Organic Support Material By The Ceramic On-Demand Extrusion Process,
2017
Missouri University of Science and Technology
Fabricating Zirconia Parts With Organic Support Material By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Andrew Scherff, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. This paper presents a further development of this process and focuses on fabricating 3 mol% yttria-stabilized zirconia (3YSZ) components that cannot be fabricated without using support structures. The 3YSZ paste is deposited through the main nozzle, and a polycaprolactone (PCL) pellet feedstock is melted and deposited through an auxiliary nozzle to build support structures. After a green part is printed and dried, the support structures are removed by heating the part to ~70 ⁰C to melt the PCL. The part is then …
Building Zr-Based Metallic Glass Part On Ti-6al-4v Substrate By Laser-Foil-Printing Additive Manufacturing,
2017
Missouri University of Science and Technology
Building Zr-Based Metallic Glass Part On Ti-6al-4v Substrate By Laser-Foil-Printing Additive Manufacturing, Yingqi Li, Yiyu Shen, Ming-Chuan Leu, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Through using Zr intermediate layers, Zr52.5Ti5Al10Ni14.6Cu17.9 metallic glass (MG) parts are successfully built on Ti-6Al-4V substrates by laser-foil-printing (LFP) additive manufacturing technology in which MG foils are laser welded layer-by-layer onto the substrate. The printed MG part is free of porosity, cracking and crystallization; additionally, its glass transition temperature, crystallization temperature, micro-hardness, and tensile strength are very similar to the original MG material. The Zr intermediate layers are aimed at preventing direct interaction between the first layer of MG foil and the Ti substrate; otherwise, the welded MG foils would peel …
Bonding Of 304l Stainless Steel To Cast Iron By Selective Laser Melting,
2017
Missouri University of Science and Technology
Bonding Of 304l Stainless Steel To Cast Iron By Selective Laser Melting, Baily Thomas, Austin T. Sutton, Ming-Chuan Leu, Nikhil Doiphode
Mechanical and Aerospace Engineering Faculty Research & Creative Works
While cast iron is widely used in industry, a major limitation is the weldability of a dissimilar material onto cast iron due to hot cracking as a result of lack of ductility from graphite flakes. Consequently, a significant amount of preheat is often employed to reduce the cooling rate in the fusion zone, which, however, may lead to distortion of the welded parts. A potential remedy could be the Selective Laser Melting (SLM) process, where only small melt pools are created and thus the overall energy input is reduced. The present paper describes an investigation of the SLM process to …
A Two-Dimensional Simulation Of Grain Structure Growth Within Substrate And Fusion Zone During Direct Metal Deposition,
2017
Missouri University of Science and Technology
A Two-Dimensional Simulation Of Grain Structure Growth Within Substrate And Fusion Zone During Direct Metal Deposition, Jingwei Zhang, Wei Li, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper, a predictive model based on a cellular automaton (CA)-finite element (FE) method has been developed to simulate thermal history and microstructure evolution during metal solidification for a laser-based additive manufacturing process. The macroscopic FE calculation that is validated by thermocouple experiment is designed to update the temperature field and a high cooling rate. A cellular automata-finite element (CAFE) method is developed to describe grain growth in the fusion zone. In the mesoscopic CA model, heterogeneous nucleation sites, grain growth orientation and rate, epitaxial growth, remelting of preexisting grains, metal addition, grain competitive growth, and columnar to equiaxed …
Influence Of Adsorbed And Nonadsorbed Polymer Additives On The Viscosity Of Magnesium Oxide Suspensions,
2017
Purdue University
Influence Of Adsorbed And Nonadsorbed Polymer Additives On The Viscosity Of Magnesium Oxide Suspensions, Lisa R. Murray, Jason E Bice, Emily G. Soltys, Christopher Perge, Sebastien Manneville, Kendra Erk
School of Materials Engineering Faculty Publications
Adsorbed polymer additives have been employed to reduce water content and improve cement workability through lowering viscosity, but the influence of over-dosage and the presence of nonadsorbed chains have yet to be fully understood. Model magnesium oxide (MgO) suspensions were used to investigate the potential processing effect of “free” chain concentration on cementitious mixtures. The rheological impact of the free chains was measured through incorporation of nonadsorbing poly(ethylene glycol) (PEG) to suspensions stabilized with an adsorbed comb-polymer superplasticizer. Analyses of the rheological data, that showed viscosity-increases and viscosity-reduction due to free PEG concentrations revealed a transition from depletion flocculation to …
Mechanical Properties Of 304l Parts Made By Laser-Foil-Printing Technology,
2017
Missouri University of Science and Technology
Mechanical Properties Of 304l Parts Made By Laser-Foil-Printing Technology, Chia-Hung Hung, Yiyu Shen, Ming-Chuan Leu, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Laser-Foil-Printing (LFP) is a novel laminated object manufacturing process for metal additive manufacturing. It fabricates three-dimensional metal parts by using a dual-laser system to weld and cut metal foils layer by layer. A main advantage of LFP is the higher cooling rate compared to powder-based laser additive manufacturing processes due to the thermal conductivity difference between foil and powder. This study focuses on the mechanical properties of 304L stainless steel parts built by the LFP process. The experimental results indicate that the yield strength and ultimate tensile strength of LFP fabricated 304L SS parts are higher by 9% and 8% …
Design And Fabrication Of Functionally Graded Material From Ti To Γ-Tial By Laser Metal Deposition,
2017
Missouri University of Science and Technology
Design And Fabrication Of Functionally Graded Material From Ti To Γ-Tial By Laser Metal Deposition, Xueyang Chen, Lei Yan, Joseph William Newkirk, Frank W. Liou
Materials Science and Engineering Faculty Research & Creative Works
Functionally graded material (FGM) is one kind of advanced material characterized by a gradual change in properties as the position varies. The spatial variation of compositional and microstructure over volume is aimed to control corresponding functional properties. In this research, when 100% γ-TiAl was directly deposited on pure Ti substrate, cracks were formed within the γ-TiAl layer. Then a six-layer crack-free functionally graded material of Ti/TiAl was designed and fabricated by laser metal deposition (LMD) method, with composition changing from pure Ti on one side to 100% γ-TiAl on the other side. The fabricated FGM was characterized for material properties …
Effects Of Area Fraction And Part Spacing On Degradation Of 304l Stainless Steel Powder In Selective Laser Melting,
2017
Missouri University of Science and Technology
Effects Of Area Fraction And Part Spacing On Degradation Of 304l Stainless Steel Powder In Selective Laser Melting, Cairlin S. Kriewall, Austin T. Sutton, Sreekar Karnati, Joseph William Newkirk, Ming-Chuan Leu
Materials Science and Engineering Faculty Research & Creative Works
In selective laser melting (SLM) systems, a large portion of powder remains unconsolidated and therefore recycling powder could make SLM more economical. Currently, a lack of literature exists specifically targeted at studying the reusability of powder. Furthermore, the definition of powder reusability is complex since powder degradation depends on many factors. The goal of the current research is to investigate the effects of area fraction and part spacing on the degradation of 304L powder in SLM. An experimental study was conducted where various area fractions and part distances were chosen and powder characterization techniques for determination of particle size distributions, …
Studying Chromium And Nickel Equivalency To Identify Viable Additive Manufacturing Stainless Steel Chemistries,
2017
Missouri University of Science and Technology
Studying Chromium And Nickel Equivalency To Identify Viable Additive Manufacturing Stainless Steel Chemistries, Zachary T. Hilton, Joseph William Newkirk, Ronald J. O'Malley
Materials Science and Engineering Faculty Research & Creative Works
Chromium and nickel equivalency modeling has long been used in welding to determine the weldability of steel chemistries. A study was conducted to determine the applicability of Cr-Ni modeling to the additive manufacturing process. Many AM methods involve rapid solidification of small melt pools, similar to welding. Chemistries with varying Cr/Ni ratios were selected for use in a selective laser melting process and modeled using known models. Initial results indicate that the standard "safe welding zone" may not directly apply to additive manufacturing. The capability to build with chemistries outside the weldability “safe zone” could result in improved and varied …
Aluminum Matrix Syntactic Foam Fabricated With Additive Manufacturing,
2017
Missouri University of Science and Technology
Aluminum Matrix Syntactic Foam Fabricated With Additive Manufacturing, M. Spratt, Joseph William Newkirk, K. Chandrashekhara
Materials Science and Engineering Faculty Research & Creative Works
Syntactic foams are lightweight structural composites with hollow reinforcing particles embedded in a soft matrix. These materials have applications in transportation, packaging, and armor due to properties such as relatively high specific stiffness, acoustic dampening, and impact absorption. Aluminum matrices are the most widely studied of metal matrix syntactic foams, but there is little to no research in regards to processing the foams with additive manufacturing. It is theorized that the fast cooling rates and limited kinetic energy input of additive could reduce two issues commonly associated with processing syntactic foams: microsphere flotation in the melt and microsphere fracture during …
Characterization Of Heat-Affected Powder Generated During Selective Laser Melting Of 304l Stainless Steel Powder,
2017
Missouri University of Science and Technology
Characterization Of Heat-Affected Powder Generated During Selective Laser Melting Of 304l Stainless Steel Powder, Austin T. Sutton, Caitlin S. Kriewall, Ming-Chuan Leu, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The selective laser melting (SLM) process is an Additive Manufacturing (AM) technique that uses a laser to fuse successive layers of powder into near fully dense components. Due to the large energy input from the laser during processing, vaporization and instabilities in the melt pool occur causing the formation of condensate and laser spatter, collectively known as heat-affected powder. Since heat-affected powder settles into the powder bed, the properties of the unconsolidated powder may be altered compromising its reusability. In this study, characterization of 304L heat-affected powder was performed through particle size distribution measurements, x-ray diffraction, metallography, energy-dispersive spectroscopy mapping, …
Influence Of Gage Length On Miniature Tensile Characterization Of Powder Bed Fabricated 304l Stainless Steel,
2017
Missouri University of Science and Technology
Influence Of Gage Length On Miniature Tensile Characterization Of Powder Bed Fabricated 304l Stainless Steel, Sreekar Karnati, Jack L. Hoerchler, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Miniature tensile specimens with varying aspect ratios were fabricated from 304L stainless steel (SS) made using powder bed additive manufacturing (AM) process. The tensile characteristics measured from these specimens were analyzed to assess the impact of gage length. The study found no impact upon varying gage length on yield and ultimate strength measurements. However, a significant impact was observed on strain measurements. This data was also used to perform Weibull statistics to estimate the stochastic performance of the material. Fractography was performed to visually identify the types of flaws. A comparative study with specimens fabricated from cold rolled annealed 304 …
Fabricating Zirconia Components With Organic Support Material By The Ceramic On-Demand Extrusion Process,
2017
Missouri University of Science and Technology
Fabricating Zirconia Components With Organic Support Material By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Andrew Scherff, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. This paper presents a further development of this process and focuses on fabricating 3 mol% yttria-stabilized zirconia (3YSZ) components that cannot be fabricated without using support structures. The 3YSZ paste is deposited through the main nozzle, and a polycaprolactone (PCL) pellet feedstock is melted and deposited through an auxiliary nozzle to build support structures. After a green part is printed and dried, the support structures are removed by heating the part to ~70°C to melt the PCL. The part is then sintered …
