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Articles 7681 - 7710 of 16793
Full-Text Articles in Materials Science and Engineering
Streamlining Alloy Design And Thermo-Mechanical Processing Parameters For High Strength Line Pipe Steels And Hot Rolled Microalloyed Steels: Process - Structure - Property Paradigm, Venkata Vignesh Natarajan
Streamlining Alloy Design And Thermo-Mechanical Processing Parameters For High Strength Line Pipe Steels And Hot Rolled Microalloyed Steels: Process - Structure - Property Paradigm, Venkata Vignesh Natarajan
Open Access Theses & Dissertations
The process parameters related to thermo-mechanical controlled processing (TMCP) of steels play a vital role in affecting the ultimate mechanical properties. We illustrate here the impact of coiling temperature, the impact of finish cooling temperature on interrupted cooling and compare with continuous cooling, and the impact of carbon and niobium on the microstructure and precipitation behavior and corresponding changes in mechanical properties, in an ultrahigh strength titanium-niobium microalloyed steel. The microstructural advancement was contemplated via transmission electron microscopy and electron backscattered diffraction (EBSD). The goal was to underscore the impact of coiling temperature on the nature and distribution of microstructural …
Heterogeneous Integration Of Metallic, Semiconducting And Dielectric Two-Dimensional Layered Material Inks For Electronics And Sensing Device Platforms, Jay Amrish Desai
Heterogeneous Integration Of Metallic, Semiconducting And Dielectric Two-Dimensional Layered Material Inks For Electronics And Sensing Device Platforms, Jay Amrish Desai
Open Access Theses & Dissertations
In monolayers of two-dimensional (2-D) layered materials, the motion of electrons is confined to a 2-D plane yielding a "zero" effective thickness with regard to the electrons. These monolayers are commonly obtained by exfoliating membranes from the bulk crystal to overcome the weak interplanar Van der Waals bonding using the so-called top-down approach. The bottom-up approach is another avenue to realize these materials, where atoms and molecules coalesce together into increasingly larger assemblies for the realization of the bulk three-dimensional (3-D) crystal. The unique properties of many of these 2-D materials make them highly sought out candidates for advancing conventional …
Effects Of Air And Other Gases In The Stabilization Process Of The Superprotonic Phase Of Cesium Dihydrogen Phosphate Within A Hermetically Sealed Chamber, Israel Martinez
Open Access Theses & Dissertations
The solid acid CsH2PO4 (CDP), exhibits a sudden increase in its proton conductivity as it’s heated above a certain temperature (around T~235oC), which makes it a very attractive candidate to be used as an electrolyte in intermediate temperature fuel cells. Unfortunately, at these temperatures the sample is not stable, as starts to dehydrate; which causes a dramatic drop in the proton conductivity over a short period of time (less than one hour). In order to inhibit, or at least delay, the dehydration process, the solid acid it’s put under a saturated water vapor atmosphere. Another method to stabilize the highly …
Magnetic And Catalytic Properties Of Transition Metal Doped Mos2 Nanocrystals, Luis Martinez
Magnetic And Catalytic Properties Of Transition Metal Doped Mos2 Nanocrystals, Luis Martinez
Open Access Theses & Dissertations
Magnetism and catalytic activity of nanoscale layered two-dimensional (2D) transition metal dichalcogenides (TMDs) have gained an increasing research interest in the recent past. To broaden the current knowledge and understanding on this subject, in this work, together with my collaborators, I study the magnetic and electrocatalytic properties of hydrothermally grown pristine and transition metal doped (10% of Co, Ni, Fe and Mn) 2H-MoS2 nanosheets/nanocrystals (NCs), with the particle size of 25-30 nm. A broad range of experimental measurements such as x-ray diffraction, transmission electron microscopy, x-ray photo absorption spectroscopy, Raman spectroscopy, magnetic, catalytic and electron spin resonance have been employed …
Solvent And Concentration Effects Governing The Hierarchical Organization Of Asphaltenes: A Small-Angle X-Ray Scattering Study, Hasan Rejoanur Rahman
Solvent And Concentration Effects Governing The Hierarchical Organization Of Asphaltenes: A Small-Angle X-Ray Scattering Study, Hasan Rejoanur Rahman
Open Access Theses & Dissertations
Asphaltenes are a group of planar molecules found in crude oil and are prone to aggregation which often causes blockage of pipes along the oil production stream resulting a huge economic downside. In an effort to understand the hierarchical organization of asphaltene in different solvents and concentrations, the solution structure of various asphaltene solutions were studied using small-angle x-ray scattering (SAXS). Solvents were chosen based on miscibility maps. Such maps are generated on the critical value of the solubility parameter difference between asphaltenes or asphaltene components, and a range of solvents. The critical factors that affect asphaltene and asphaltene component …
Tribological Characterization Of Ti-Based Alloys For Biomedical Applications In Simulated Body Fluid, Edgar Reyes
Tribological Characterization Of Ti-Based Alloys For Biomedical Applications In Simulated Body Fluid, Edgar Reyes
Open Access Theses & Dissertations
Tribology is a terminology introduced in the 1960's and it is a study that relates to the investigation of the damage of materials. Titanium, as a material used for a wide range of application, it has been brought to the attention of researchers some characteristics such as its much lower density if compared to steel, its capability as an alloying agent with an amount of metals to enhance physical and mechanical properties, to name just a few characteristics. This paper will discuss the performance on tribology behavior in two different Titanium alloys. These Titanium alloys are Ti-6Al-4V (Ti64), and Ti-24Nb-4Zr-8Sn …
Tungsten Doping Induced Superior Mechanical Properties Of Hafnium Oxide For Energy Applications, Ann Marie Uribe
Tungsten Doping Induced Superior Mechanical Properties Of Hafnium Oxide For Energy Applications, Ann Marie Uribe
Open Access Theses & Dissertations
Hafnium oxide, or hafnia, is a high temperature refractory material with good electrical, chemical, optical, and thermodynamic properties. The effects of dopants have been widely studied, especially after the discovery of ferroelectricity induced in hafnia thin films. While attractive and used in the opto-electronic, memory devices, and semiconductor industries, there is a lack in the literature on enhancing the mechanical properties of hafnium oxide, specifically through doping it with tungsten, another material of interest particularly for future high temperature device applications. Thus, this work aimed to grow hafnia thin films doped with varying amounts of tungsten. The samples were grown …
Evaluation Of Large Area Additively Manufactured Fiber Reinforced Acrylonitrile Butadiene Styrene (Abs), Kevin Schnittker
Evaluation Of Large Area Additively Manufactured Fiber Reinforced Acrylonitrile Butadiene Styrene (Abs), Kevin Schnittker
Open Access Theses & Dissertations
To enable the advancement of large-scale additive manufacturing processes, it is necessary to establish and standardize methodologies to characterize the mechanical properties of printed test coupons. Due to the large size of the print beads, conventional test standards are inadequate. The focus of this study was to determine the feasibility of using Digital image correlation (DIC) technology as a key enabler for robust data collection of strain measurements of large 3D printed parts. To incorporate the DIC measurements, a novel method was developed to prepare large 20 wt.% glass filled ABS test coupons for adequate contrast. Through this technique, Poisson's …
Modeling Crevice Corrosion Of Nickel Alloy 625 In Seawater, Linsey Grzeschik
Modeling Crevice Corrosion Of Nickel Alloy 625 In Seawater, Linsey Grzeschik
Williams Honors College, Honors Research Projects
In this work, COMSOL Multiphysics was used to model crevice corrosion of Nickel Alloy 625 in seawater. Initial model parameters included a bulk solution of 0.6M (Cl-) ASTM D1141-98 artificial seawater, a crevice length of 12.7mm, and applied current of 0.44VSHE. A crevice gap of 7μm and 10μm were compared using a 3.0m polarization curve of the simulated critical crevice solution for Alloy 625. A constant crevice gap of 10μm was used to compare varying polarization curves of 3.0m, 3.5m, and deaerated seawater. The model found a variation in free chloride concentration from the bulk to …
Design Of Shape-Conforming Nosecone For Optimal Fluid Flow From Transonic To Supersonic Range, Anna Tombazzi
Design Of Shape-Conforming Nosecone For Optimal Fluid Flow From Transonic To Supersonic Range, Anna Tombazzi
Williams Honors College, Honors Research Projects
Modern flight vehicles, such as rockets, missiles, and airplanes, experience a force caused by forebody wave drag during the flight. This drag force is induced when the frontal point of each vehicle breaks the pressure wave during flight. Efforts to reduce this wave drag force to improve flight efficiency include modifying the nosecone profile of the flight vehicles to lower the drag force.
This project revolved around creating a design to make the transformation of nosecone shapes from a ¾ Parabolic profile to a ½ Power Series profile possible, mid-flight. Using a novel nosecone assembly, shape memory alloys (SMAs) and …
Structural, Transport, And Topological Properties Induced At Complex-Oxide Hetero-Interfaces, Justin K. Thompson
Structural, Transport, And Topological Properties Induced At Complex-Oxide Hetero-Interfaces, Justin K. Thompson
Theses and Dissertations--Physics and Astronomy
Complex-oxides have seen an enormous amount of attention in the realm of Condensed Matter Physics and Materials Science/Engineering over the last several decades. Their ability to host a wide variety of novel physical properties has even caused them to be exploited commercially as dielectric, metallic and magnetic materials. Indeed, since the discovery of high temperature superconductivity in the “Cuprates” in the late 1980’s there has been an explosion of activity involving complex-oxides. Further, as the experimental techniques and equipment for fabricating thin films and heterostructures of these materials has improved over the last several decades, the search for new and …
Hydrophobicity Of Low Temperature Vibrating Surfaces, Christian Fergusson
Hydrophobicity Of Low Temperature Vibrating Surfaces, Christian Fergusson
Theses and Dissertations
This study proposes a method to enhance the anti-icing capabilities of superhydrophobic surfaces by utilizing vibration to further reduce contact time of an impacting droplet in addition to keeping the droplet in the Cassie-Baxter regime, where surface adhesion is lower than the opposing Wenzel regime. We tested this with two methods: by investigating the effects of vibration normal to the plane of a superhydrophobic surface being impacted by water droplets in a room temperature environment, with the surface horizontal in a room temperature environment and tiled in a subzero degree environment. The amplitude and frequency of the vibration were varied …
Liquid Interaction With Non-Wettable Surfaces Structured With Macroscopic Ridges, Mehran Abolghasemibizaki
Liquid Interaction With Non-Wettable Surfaces Structured With Macroscopic Ridges, Mehran Abolghasemibizaki
Theses and Dissertations
Self-cleaning, anti-corrosion, anti-icing, dropwise-condensation, and drag-reduction are some applications in which superhydrophobic surfaces are implemented. To date, all the studies associated with superhydrophobic surfaces have been dedicated to understanding the liquid interaction with surfaces that are macroscopically smooth. The current study investigates the solid-liquid interaction of such surfaces which are fully decorated with macroscopic ridges (ribbed surfaces). In particular, the drop motion and impact on our newly designed non-wettable ribbed surface have been investigated in this work. Our experimental investigations have shown that liquid drops move faster on the ribbed surfaces due to lower friction induced by such a surface …
Consuming Digital Debris In The Plasticene, Stephen R. Parks
Consuming Digital Debris In The Plasticene, Stephen R. Parks
Theses and Dissertations
Claims of customization and control by socio-technical industries are altering the role of consumer and producer. These narratives are often misleading attempts to engage consumers with new forms of technology. By addressing capitalist intent, material, and the reproduction limits of 3-D printed objects’, I observe the aspirational promise of becoming a producer of my own belongings through new networks of production. I am interested in gaining a better understanding of the data consumed that perpetuates hyper-consumptive tendencies for new technological apparatuses. My role as a designer focuses on the resolution of not only the surface of the object through 3-D …
Influence Of Atmospheric Clearness On Pdlc Switchable Glazing Transmission, Aritra Ghosh, Brian Norton, Tapas K. Mallick
Influence Of Atmospheric Clearness On Pdlc Switchable Glazing Transmission, Aritra Ghosh, Brian Norton, Tapas K. Mallick
Articles
Electrically activated switchable polymer dispersed liquid crystal (PDLC) is suitable for adaptive windows. A particular type requires 20V to become 71% transparent while in the absence of power it is 27% transparent. Glazing transmission changes with light incident angle. As the clearness of a sky changes the fraction changes alter of direct insolation (that has an azimuthally changing incident) and diffuse insolation (that has a largely constant incident). Thus, the effective overall incident angle determining the glazing transmittance also changes. In this work for the first time, the variation of PDLC glazing transmission with clearness index has been investigated.
Effect Of Thickness On The Structure And Corrosion Performance Of Sputtered Ce-Al-O Coatings On Al 2024-T3 Alloy Substrates, Yuanyuan Liu, Jiamu Huang, Lilu Qin, James B. Claypool, Matthew J. O'Keefe, Yiming Jiang
Effect Of Thickness On The Structure And Corrosion Performance Of Sputtered Ce-Al-O Coatings On Al 2024-T3 Alloy Substrates, Yuanyuan Liu, Jiamu Huang, Lilu Qin, James B. Claypool, Matthew J. O'Keefe, Yiming Jiang
Materials Science and Engineering Faculty Research & Creative Works
Ce-Al-O coatings with thicknesses between ca. 136 nm and 1094 nm were deposited on Al 2024-T3 alloy substrates using magnetron co-sputtering of independent Al and CeO2 targets. The Ce-Al-O coatings with thicknesses from ca. 136 nm to 490 nm were compact, dense, and did not have distinct X-ray diffraction peaks. The ca. 1094 nm thick Ce-Al-O coating exhibited a columnar-textured outer layer ∼700 nm thick and a dense, ∼390 nm thick inner layer. X-ray photoelectron spectroscopy analysis revealed that the Ce-Al-O coatings contained Ce (III) species, and that the Al/Ce atomic ratio decreased with increasing coating thickness. Electrochemical corrosion data …
An Energy-Based Approach To Assess And Predict Erosive Airfoil Defouling, Arthur Rudek, Thomas-Alexander Zitzmann, Geral Russ, Barry Duignan
An Energy-Based Approach To Assess And Predict Erosive Airfoil Defouling, Arthur Rudek, Thomas-Alexander Zitzmann, Geral Russ, Barry Duignan
Articles
A dynamic indentation experiment is presented for assessment of the adhesive behavior of a range of coatings in erosive defouling of commercial aircraft engines using CO2 dry-ice. A series of experiments is presented in which particles made from a reference material (polyoxymethylene – POM) and from CO2 dry-ice are made to impact compressor airfoils under a range of impact angle and velocity conditions. The airfoils investigated are coated with an indicator material (PTFE), which is typically used to visualise the defouling effect in large scale compressor defouling experiments. In addition, fouled compressor airfoils taken from service and coated with a …
Sand Distribution Effect On Three Dimensional Printed Sand Properties, Kip Woods
Sand Distribution Effect On Three Dimensional Printed Sand Properties, Kip Woods
Dissertations and Theses @ UNI
The purpose of this study was to assess the performance characteristics of commercially available round grain silica sand for the use in three-dimensional sand printers. Two different average diameters were selected to examine the effects of screen distribution on printing performance; these diameters were 57-grain fineness number (GFN) and 70 GFN. These sands were a high purity round grain silica and had low trace contaminates, to reduce any possible influence from contaminates.
The resin system utilized in this investigation was a commercially available Furan resin system. Two test specimens were used in this study the American Foundry Society (AFS) tensile …
A Simple Model For Elastic-Plastic Contact Of Granular Geomaterials, Jian Wang, Qimin Li, Changwei Yang, Yidan Huang, Caizhi Zhou
A Simple Model For Elastic-Plastic Contact Of Granular Geomaterials, Jian Wang, Qimin Li, Changwei Yang, Yidan Huang, Caizhi Zhou
Materials Science and Engineering Faculty Research & Creative Works
We propose a simple elastic-plastic contact model by considering the interaction of two spheres in the normal direction, for use in discrete element method (DEM) simulations of geomaterials. This model has been developed by using the finite element method (FEM) and nonlinear fitting methods, in the form of power-law relation of the dimensionless normal force and displacement. Only four parameters are needed for each loading-unloading contact process between two spheres, which are relevant to material properties evaluated by FEM simulations. Within the given range of material properties, those four parameters can be quickly accessed by interpolating the data appended or …
Femtosecond Laser-Matter Interactions In Ternary Zinc Phosphate Glasses, J. Hernandez-Rueda, N. W. Troy, P. Freudenberger, Richard K. Brow, D. M. Krol
Femtosecond Laser-Matter Interactions In Ternary Zinc Phosphate Glasses, J. Hernandez-Rueda, N. W. Troy, P. Freudenberger, Richard K. Brow, D. M. Krol
Materials Science and Engineering Faculty Research & Creative Works
We investigate the interaction of ultrashort laser pulses with ternary zinc phosphate glasses. We explore the viability of ten different glass compositions with different levels of alumina to inscribe optical waveguides via the fs-laser direct writing technique, finding that only samples with [O]/[P] ratios of 3.25 are suitable candidates. We also test a zinc magnesium phosphate glass to fabricate waveguide Bragg gratings in order to generate filters and mirrors with specific spectral properties. Confocal Raman spectroscopy inspection shows that laser-damaged material exhibits a relative intensity decrease and a subtle blue-shift on the 1209 cm-1 Raman peak, which implies a relative …
A Scientific Approach To Understanding The Head Trauma Endured By A Mixed Martial Arts Fighter, John William Michael Sorbello
A Scientific Approach To Understanding The Head Trauma Endured By A Mixed Martial Arts Fighter, John William Michael Sorbello
Mechanical & Aerospace Engineering Theses & Dissertations
The purpose of this research is to gain some insight on the type of head trauma an athlete may encounter during mixed martial arts (MMA) competition. These athletes endure continuous blows to the head throughout their training and fighting career. The knowledge obtained from this research may assist MMA athletes and trainers in assessing the way they train, how they compete and, more importantly, how long they choose to compete in their amateur or professional MMA career.
The analysis is performed by first creating a three-dimensional solid model of the human head based on geometric coordinates originally obtained from a …
Saw Assisted Domain Wall Motion In Co/Pt Multilayers, Westin Edrington, Uday Singh, Maya Abo Dominguez, James Rehwaldt Alexander, Rabindra Nepal, Shireen Adenwalla
Saw Assisted Domain Wall Motion In Co/Pt Multilayers, Westin Edrington, Uday Singh, Maya Abo Dominguez, James Rehwaldt Alexander, Rabindra Nepal, Shireen Adenwalla
Shireen Adenwalla Papers
The motion of domain walls in thin ferromagnetic films is of both fundamental and technological interest. In particular, the ability to use drivers other than magnetic fields to control the positions of domain walls could be exciting for memory applications. Here, we show that high frequency dynamic strain produced by surface acoustic waves is an efficient driver of magnetic domain walls in ferromagnetic films with perpendicular anisotropy. A standing surface acoustic wave of resonant frequency 96.6MHz increases the domain wall velocities in thin films of [Co/Pt]n by an order of magnitude compared to magnetic fields alone. This effect is highly …
An Injectable Thermosensitive Biodegradable Hydrogel Embedded With Snap Containing Plla Microparticles For Sustained Nitric Oxide (No) Delivery For Wound Healing, Nikhil Mittal
Dissertations, Master's Theses and Master's Reports
After injury, wound healing is a complex sequential cascade of events essential for the proper recovery of the wound without the scar formation. Nitric oxide (NO) is a small, endogenous free-radical gas with antimicrobial, vasodilating and growth factor stimulating properties. NO has wide biomedical application especially in wound healing however, its usability is hindered due its administration problem as it is highly unstable.
In this work, poly (l-lactic acid) microparticles encapsulated with NO donor S-nitroso-N-acetyl-D-penicillamine (SNAP) were prepared using water-in-oil-water double emulsion solvent evaporation method for controlled delivery for NO at the specific site. The NO release from SNAP-PLLA microparticles …
The Microstructural Annealing Response Of Cold Gas Dynamically Sprayed Al 6061, Clayton Andrew Cushway
The Microstructural Annealing Response Of Cold Gas Dynamically Sprayed Al 6061, Clayton Andrew Cushway
UNF Graduate Theses and Dissertations
The Cold-Gas Dynamic-Spray process also known as Cold Spray (CS) has been researched for three decades. The CS process is a solid-state deposition technique via supersonic velocity of powder particles at a temperature significantly below the melting point of the spray material. This thesis presents background on the overall CS process parameters, and additional information on the microstructural and mechanical properties of typical Cold Sprayed materials.This Thesis primarily presents a study on the microstructural annealing response of CS Al 6061. It should be noted that for this study, the term “annealing” is used in the sense of the classical metallurgical …
ผลของการเติมยิปซั่มและดินขาวต่อเฟสและสมบัติของผลิตภัณฑ์แคลเซียมซิลิเกตไฮเดรตภายใต้สภาวะไฮโดรเทอร์มัล, อัณศยา เอกสาธิต
ผลของการเติมยิปซั่มและดินขาวต่อเฟสและสมบัติของผลิตภัณฑ์แคลเซียมซิลิเกตไฮเดรตภายใต้สภาวะไฮโดรเทอร์มัล, อัณศยา เอกสาธิต
Chulalongkorn University Theses and Dissertations (Chula ETD)
สารประกอบแคลเซียมซิลิเกตไฮเดรตเป็นองค์ประกอบสำคัญที่ส่งผลต่อสมบัติของผลิตภัณฑ์วัสดุก่อสร้างต่างๆ เนื่องจากเป็นเฟสหลักที่ทำหน้าที่เชื่อมประสานเฟสต่างๆในวัสดุก่อสร้างทำให้เกิดความแข็งแรงขึ้น ในงานวิจัยนี้ทำการศึกษาผลของการเติมดินขาวและยิปซั่มต่อเฟสของแคลเซียมซิลิเกตไฮเดรตที่เกิดขึ้นและสมบัติของผลิตภัณฑ์ที่เตรียมได้ภายใต้สภาวะไฮโดรเทอร์มัลที่อุณหภูมิ 180 องศาเซลเซียส จากการทดลองพบว่าเมื่อเพิ่มอัตราส่วน Ca/Si ชิ้นงานที่เตรียมได้จะเกิดเฟสโทเบอร์โมไรท์และแคลเซียมซิลิเกตไฮเดรตเจลในปริมาณสูงขึ้น ส่งผลทำให้ ความต้านแรงดัดของชิ้นงานเพิ่มขึ้น การเติมยิปซั่มจะเร่งให้เกิดเฟสโทเบอร์โมไรท์และแคลเซียมซิลิเกตไฮเดรตเจล ซึ่งจะส่งผลทำให้ความต้านแรงดัดสูงขึ้น แต่เมื่อเติมยิปซั่มที่อัตราส่วน S/(Si+S) มากกว่า 0.025 จะส่งผลทำให้เกิดเฟสแอนไฮไดรต์เพิ่มมากขึ้น ซึ่งจะทำให้ความต้านแรงดัดมีค่าลดลง ในขณะที่การเติมดินขาวจะช่วยส่งเสริมการเกิดเฟส โทเบอร์โมไรท์แต่จะยับยั้งการทำปฏิกิริยาระหว่างแคลเซียมไฮดรอกไซด์กับควอตซ์ทำให้เกิด แคลเซียมซิลิเกตไฮเดรตเจลลดลง ส่งผลให้ความต้านแรงดัดจึงมีค่าลดลง เมื่อเติมดินขาวร่วมกับยิปซั่มพบว่า สมบัติของชิ้นงานที่เตรียมได้จะขึ้นกับชนิดของสารตัวเติมที่ควบคุมปฏิกิริยา โดยยิปซั่มจะควบคุมการเกิดปฏิกิริยาเมื่อเติมดินขาวในปริมาณน้อย การเติมยิปซั่มในปริมาณที่สูงขึ้นจะทำให้เฟสแคลเซียมซิลิเกตไฮเดรตเจลและโทเบอร์โมไรท์มีปริมาณที่สูงขึ้น แต่เมื่อชิ้นงานนั้นมีการเติมดินขาวในปริมาณที่สูง ดินขาวจะเริ่มควบคุมการเกิดปฏิกิริยาร่วมกับยิปซั่มส่งผลให้เกิดเฟสโทเบอร์โมไรท์ได้ดีขึ้นแต่จะยับยั้งการเกิดเฟสแคลเซียมซิลิเกตไฮเดรตเจล โดยในกรณีที่เตรียมชิ้นงานที่อัตราส่วน Ca/(Si+S+Al) ต่ำ จะทำให้ปฏิกิริยาระหว่างสารตั้งต้นเกิดได้อย่างสมบูรณ์ไม่พบพอร์ตแลนไดต์หลงเหลือในระบบ ส่งผลให้ชิ้นงานมีความต้านแรงดัดสูง ในขณะที่ชิ้นงานที่เตรียมด้วยอัตราส่วน Ca/(Si+S+Al) สูง จะมี พอร์ตแลนไดต์หลงเหลือในชิ้นงานในปริมาณสูง ส่งผลทำให้ค่าความต้านแรงดัดมีค่าต่ำ
Development And Evaluation Of Post-Production Oxygenation Techniques For The Augmentation Of Biochar, Matthew David Huff
Development And Evaluation Of Post-Production Oxygenation Techniques For The Augmentation Of Biochar, Matthew David Huff
Chemistry & Biochemistry Theses & Dissertations
Biochar is the carbon rich solid by-product of biomass pyrolysis. Interest in biochar can be broken down to several main categories: use as a carbon sequestration agent, use as a medium for the removal via adsorption of unwanted materials in wastewater, and as a soil amendment for the increase of cation exchange capacity (CEC). In order to generate a biochar which is stable enough for carbon sequestration, higher temperature pyrolysis must be used in order to ensure a lower O:C ratio in order to increase the half-life of biochar in soil. This dissertation addresses the evaluation of biochars made from …
Characterization And Tailoring Of Powder Used In Additive Manufacturing And Plasma Spheroidization, Caitlin S. Kriewall
Characterization And Tailoring Of Powder Used In Additive Manufacturing And Plasma Spheroidization, Caitlin S. Kriewall
Masters Theses
"There are many processes that use metal powder as the starting material for the production of parts. With the growth of these manufacturing techniques, more critical part applications are being considered. In order to fully understand the process and create consistent parts, powder properties need to be well understood. Selective laser melting (SLM) is a powder bed-based additive manufacturing process. During processing, heat-affected powders are generated and can deposit within the build area. The current work investigated the characterization of heat-affected 304L stainless steel powder using techniques such as scanning electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy to detect …
Mitigation Of Environmental Hazards Of Sulfide Mineral Flotation With An Insight Into Froth Stability And Flotation Performance, Muhammad Badar Hayat
Mitigation Of Environmental Hazards Of Sulfide Mineral Flotation With An Insight Into Froth Stability And Flotation Performance, Muhammad Badar Hayat
Doctoral Dissertations
"Today's major challenges facing the flotation of sulfide minerals involve constant variability in the ore composition; environmental concerns; water scarcity and inefficient plant performance. The present work addresses these challenges faced by the flotation process of complex sulfide ore of Mississippi Valley type with an insight into the froth stability and the flotation performance. The first project in this study was aimed at finding the optimum conditions for the bulk flotation of galena (PbS) and chalcopyrite (CuFeS₂) through Response Surface Methodology (RSM). In the second project, an attempt was made to replace toxic sodium cyanide (NaCN) with the biodegradable chitosan …
Turbulence, Entrainment And Low-Order Description Of A Transitional Variable-Density Jet, Bianca Viggiano, Tamara S. Dib, N. Ali, L. G. Mastin, Raúl Bayoán Cal, S. A. Solovitz
Turbulence, Entrainment And Low-Order Description Of A Transitional Variable-Density Jet, Bianca Viggiano, Tamara S. Dib, N. Ali, L. G. Mastin, Raúl Bayoán Cal, S. A. Solovitz
Mechanical and Materials Engineering Faculty Publications and Presentations
Geophysical flows occur over a large range of scales, with Reynolds numbers and Richardson numbers varying over several orders of magnitude. For this study, jets of different densities were ejected vertically into a large ambient region, considering conditions relevant to some geophysical phenomena. Using particle image velocimetry, the velocity fields were measured for three different gases exhausting into air – specifically helium, air and argon. Measurements focused on both the jet core and the entrained ambient. Experiments considered relatively low Reynolds numbers from approximately 1500 to 10 000 with Richardson numbers near 0.001 in magnitude. These included a variety of …
Implementation Of Magnesium Alloy Az91d On Wire And Arc Additive Manufacturing, David Adrian Martinez Holguin
Implementation Of Magnesium Alloy Az91d On Wire And Arc Additive Manufacturing, David Adrian Martinez Holguin
Open Access Theses & Dissertations
As progress on Additive Manufacturing (AM) techniques focusing on ceramics and polymers evolve, metals continue to be a challenging material to manipulate when fabricating products. Current methods, such as Selective Laser Sintering (SLS) and Electron Beam Melting (EBM) face many intrinsic limitations due to the nature of their processes. Material selection, elevated cost and low deposition rates are some of the barriers to consider when one of these methods is to be used for the fabrication of engineering products. The research here presented demonstrates the use of a Wire and Arc Additive Manufacturing (WAAM) system for the creation of metallic …