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Today's society is currently developing lithium-ion batteries to eventually replace the use of fossil fuels. High entropy oxides is a new type of material to use as an anode in the lithium-ion battery. These high entropy oxides may consist of a few different transition metals including lithium and oxygen. In this report was (MgCoNiZn)1-xLixO synthesized with a method called Pechini with a molar fraction of x=0.35. This study compares the results from a reference study that has shown the potential of the electrochemical characteristics of (MgCoNiZn)1-xLixO for application as anode in a lithium-ion battery.  The synthesis starts with a heating step to remove all the organics in the composition. The powder consists of several structures and, therefore goes through a calcination step to dissolve all of the intermediate phases into the rock-salt structure. The structure of the powder had a lattice constant of 4,138Å. The powder was made into a slurry containing Carbon black, PVDF and NMP to later get coated by a Dr. Blade. After drying the coating the cell was then assembled with lithium as metal cathode and 1M LiPF6 in 1:1 EC/DMC as electrolyte. After the cell was assembled it, went through electrochemical properties test using a potentiostat and the cell being inside a in a climate chamber at 25°C.  7 cycles were done to plot a cyclic voltammetry graph as well as a discharge-charge test was performed. The cyclic voltammetry and discharge-charge test was run with a voltage range of 0,053 V. The discharge-charge test was run at a current density of 100 mA/g and a constant current of 42,68 mA. / Dagens samhälle genomgår en stor utveckling av litium-jon batterier för att kunna ersätta användningen av fossila bränslen. Höga entropi oxider är ny typ av material som används som anod material för litiumjonbatterier. Dessa höga entropi oxider kan bestå av en rad olika övergångsmetaller inklusive litium och syre i sammansättningen. I den här rapporten var (MgCoNiZn)1-xLixO syntetiserad med en metod som heter Pechini med ett molbråk på x=0,35. En studie har visat potentialen i dem elektrokemiska beetenden av (MgCoNiZn)1-xLixO till applicering som en anode i ett litiumjon batteri.  Syntetiseringen började med ett uppvärmningsteg för att bränna bort alla organiska föreningar. Resulterade pulvret bestod av olika strukturer, och till ett kalcinerings steg för att lösa upp mellanfaserna till NaCL-struktur. Strukturen på pulvret hade en gitter constant på 4,138 Å. Pulvret gjordes till en slurry som innehåller amorft kol, PVDF och NMP för att sedan belägga elektroden med en Dr.Blade. Efter beläggningen har fått torka monterades cellen med litium som katod och 1M LiPF6 in 1:1 EC/DMC som elektrolyt. Tester utfördes på cellen med hjälp av en potentiostat medans cellen var förvaren i en klimatkammare i 25°C.  7 stycken cykler kördes för att plotta en cyklisk voltametri graf samt en urladdning-laddning prov utfördes. Cykliska voltametrin och urladdning-laddnings prov utfördes med ett spänningsintervall på 0,05-3,0V. Urladdning-laddnings provet hade en strömtäthet på 100 mA/g och en konstant ström på 42,68 mA.

It was found that the measurements captured by confocal microscopy and scanning electron microscopy had a statistically significant difference for bovine tissue. There was not a statistically significant for porcine and poultry tissue. The intent of the study is to perform a comparative study to examine efficacy of two distinct technologies for a singular purpose: tissue surface roughness characterization. The two technologies compared are a confocal reflectance microscope and a scanning electron microscope. The comparison was made by comparing two surface roughness parameters [Ra and Rq] within ImageJ. The study examined three different animal species [porcine, bovine, and poultry] to highlight if different tissues presented alternative conclusions for the efficiency of either technology. Additional analysis was produced comparing two cutting methods [Kleen Kut versus conventional], as well as six different poultry processing technique combinations.

Frozen, thawed and osmotically-dehydrated highbush (HB) (Vaccinium corymbosum) and rabbiteye (RB) (V. virgatum) blueberries were analyzed under a scanning electron microscope (SEM) to observe microstructural differences in their skin. Rabbiteye blueberries of both frozen, thawed and osmotically-dehydrated treatments, had thicker skins than highbush blueberries. Rabbiteye blueberries, collected from local farms, packed and blast frozen (PBF), had thinner skins than individually quick-frozen (IQF) blueberries. Washing berries prior to freezing had no effect on skin thickness. Sensory analysis of samples determined there were no differences (p > 0.05) between PBF and IQF methods and species with respect to skin intactness, grittiness, sweetness, and blueberry flavor. IQF berries obtained from one farm had tougher skin (p ≤ 0.05) than other berries regardless of treatment. RB were rated lower in juiciness and higher in grittiness than HB berries whereas LH berries were rated lower in shriveling and higher in skin intactness.

For reducing the CO2 footprint in many industrial fields, the goal is to produce lighter components. The aluminium-silicon (Al-Si) cast alloys are promising candidates to fulfill these goals with a high weight-to-strength ratio, good corrosion properties, excellent castability, and recyclable material. However, the variations within these components need to be understood to produce high-performance components for critical applications. The main reason for the rejection in these applications is defects and microstructural features that reduce the mechanical properties. The addition of copper (Cu) is one way of increasing the mechanical properties in Al-Si alloys and is commonly used in the automotive industry. Casting defects harm the mechanical properties, and these defects can be reduced by improving the melt quality, the correct design of the component, and the gating system. The study aims to investigate the static mechanical properties and the crack initiation and propagation under cyclic loading in an Al-7Si-Mg cast alloy with state-of-the-art experiments. The main focuses were on the effect of the HIP process and the role of Cu addition. In-situ cyclic testing using a scanning electron microscope coupled with electron back-scattered diffraction, digital image correlation, focused ion beam (FIB) slicing, and computed tomography scanning was used to evaluate the complex interaction between the crack path and the microstructural features. The amount of Cu retained in the α-Al matrix in as-cast and heat-treated conditions significantly influenced the static mechanical properties by increasing yield strength and ultimate tensile strength with a decrease in elongation. The three-nearest-neighbor distance of eutectic Si and Cu-rich particles and crack tortuosity were new tools to describe the crack propagation in the alloys, showing that a reduced distance between the Cu-rich phases is detrimental for the mechanical properties. Three dimensional tomography using a FIB revealed that the alloy with 3.2 wt.% Cu had a significantly increased quantity of cracked Si particles and intermetallic phases ahead of the crack tip than the Cu-free alloy. The effect of Cu and HIP process in this work shows the complex interaction between the microstructural features and the mechanical properties, and this needs to be considered to produce high-performance components. / Ett sätt att nå målen med minskade koldioxidutsläpp inom industrin är att producera lättare komponenter. Aluminium-kisel (Al-Si) gjutna legeringar är därför ett bra alternativ då dessa legeringar har ett bra förhållande mellan hållfasthet och vikt, goda korrosionsegenskaper, utmärkt gjutbarhet och är ett återvinningsbart material. En av de största utmaningarna för att producera högpresterande komponenter för kritiska applikationer är variationerna i egenskaper inom dessa komponenter. Orsaken till att inte gjutna Al-Si legeringar andvänds i dessa applikationer är förståelsen av defekter och mikrostruktuella faser påverkar de mekaniska egenskaperna negativt. Koppar (Cu) tillsätts i Al-Si legeringar för att öka de mekaniska egenskaperna vilket ofta nyttjas inom bilindustrin. Hot isostatic pressing (HIP) prosessen är en annan möjlighet att förbättra de mekaniska egenskaperna genom att reducera porositeter i materialet. Studien syftar till att undersöka de mekaniska egenskaperna och sprickinitiering och spricktillväxt i en gjuten legering av Al-7Si-Mg med utmattningstestning i svepelektronmikroskop (SEM) i kombination med electron backscatter diffraction, digital image correlation och focused ion beam (FIB). Mängden Cu i Al-Si legeringen påverkade de statiska mekaniska egenskaperna genom att öka sträckgränsen och brottgränsen. Tillsats av Cu upp till 1.5 vikt.% påverkar inte spricktillväxten märkbart. Däremot förändras beteendet markant vid tillsatser av Cu på mer än 3.0 vikt.% som resulterade i en markant reducering i duktilitet. I det värmebehandlade materialet påverkades de mekaniska egenskaperna av Al-matrisen och mängden intermetalliska faser. Avståndet mellan Cu faserna och Si faserna används för att beskriva spricktillväxten i Al-Si legeringarna. Detta tillsammans med tredimensionell tomografi visade att legeringen med 3.2 vikt.% Cu hade en ökad mängd sprickor i området framför den avancerande sprickan, vilket inte den Cu fria legeringen visade. Al-Si legeringen som utsattes för HIP-processen och värmebehandlingen visade att materialets mikrostruktur i gjutet tillstånd påverkade resultatet. HIP processen slöt porositerena i alla undersökta prover och förbättrade de mekaniska egenskaperna. Dessa resultat kommer kunna användas för att konstruera mer högpresterande komponenter.

This dissertation demonstrates the first of its kind distributed magnetic field sensor based on a fiber optic distributed acoustic sensing (DAS) scheme. Ferromagnetic nickel and Metglas® were dispersed internally within a fiber optic preform and then drawn on an in-house fiber optic draw tower to lengths in the kilometers. Due to the close proximity of the ferromagnetic metals and fiber optic core, the magnetostrictive strain response of the ferromagnetic materials when exposed to a magnetic field would perturbate within the fiber cladding and transfer that strain, internally, to the fiber optic core. Strain resulting from the magnetostrictive effect allows the DAS based sensor to accurately translate strain into readable magnetic field data. Due to the high sensitivity seen in this sensor design, multiparameter sources, acoustic and magnetic fields, were tested and validated and a three dimensional magnetic-field vector sensor was proposed. Numerical analysis of the novel sensor design was first implemented using COMSOL Multiphysics, where inputs such as magnetostrictive element shape, size, distance, and number were first investigated. Upon optimizing system constraints, the sensor design was further modified such that single mode operation was consistent across multiple fiber draws while retaining high strain transfer from the ferromagnetic elements to the fiber optic core. Ferromagnetic material selection was evaluated as a function of the saturation magnetostriction constants and a total of 4 modules were used to fully characterize the complex physics involved in this sensor design. All fabrication and testing were performed in-house using a full scale 3-story fiber draw tower and custom environmental testing stations to imitate naturally occurring events such as magnetic or acoustic point sources. A unique stacking method was used to embed ferromagnetic nickel and Metglas® into a fiber optic preform which when combined with a custom fiber draw process resulted in consistent multi-material fibers drawn to lengths of 1-km. In-house testing facilities included different types of electromagnetic generators, in addition to a soil test bed, and an outdoor test bed which allowed 100 meters of fiber to be tested simultaneously. All tested sensors demonstrated high strain transfer capabilities on the order of 0.01-10 μϵ depending on the materials used, ferromagnetic rod number, and core to metal spacing. Due to the sensitivity of the system the difference between AC and DC was distinct, and directional magnetostriction was studied. Transverse and longitudinal magnetic wave propagation was controlled through a solenoid and rectangular Helmholtz coil, both built in-house. A three-dimensional magnetic field vector sensor was proposed due to the success of the magnetic field sensor, and a design was proposed and initially tested to validate direction as a function of field strength and distance. To summarize, this dissertation explores the first fully distributed magnetic field sensor using DAS based techniques and one of the first multi-material fiber draw processes which can produce consistent single mode fiber up to 1-km. Due to extensive FEA modeling, multiple iterations of the magnetic sensor were fully characterized and an equation describing the relationship between sensor design and strain transfer has been created and validated experimentally. Multi-parameter tests including acoustic and magnetic fields were implemented and an algorithm was developed to separate the mixed signals. Finally, a test was performed to demonstrate the feasibility of sensing magnetic fields directionally. Cumulative results demonstrate a high-quality sensor alternative to current designs which may surpass other magnetic sensors due to innate multi-parameter capabilities, in addition to the inexpensive production cost and extremely long operating lengths. / Doctor of Philosophy / This dissertation demonstrates the first of its kind distributed magnetic field sensor based on a fiber optic distributed acoustic sensing (DAS) scheme. Ferromagnetic nickel and Metglas® were dispersed internally within a fiber optic preform and then drawn on an in-house fiber optic draw tower to lengths in the kilometers. Due to the close proximity of the ferromagnetic metals and fiber optic core, the magnetostrictive strain response of the ferromagnetic materials when exposed to a magnetic field would perturbate within the fiber cladding and transfer that strain, internally, to the fiber optic core. Strain resulting from the magnetostrictive effect allows the DAS based sensor to accurately translate strain into readable magnetic field data. Due to the high sensitivity seen in this sensor design, multiparameter sources, acoustic and magnetic fields, were tested and validated and a three dimensional magnetic-field vector sensor was proposed. Numerical evaluation of the sensing structure was perused before experimental testing using COMSOL Multiphysics. Experimental and numerical evaluations were compared and showed a high degree of certainty which allowed expedited design modifications. Sensor characterization included scanning electron microscopy, and electron diffraction spectroscopy, which provided insight into material composition and fiber polishing quality. Due to the high-quality results attained in the combined acoustic and magnetic field tests, a final design was proposed to gather magnetic field data as a vector, showing both magnitude and direction. The 3D magnetic field vector sensor was partially validated based on a test which compared intensity with distance and a design and methodology was proposed to fully test and characterize this design. To summarize, a novel magnetic field sensor, capable of multi-parameter sensing, was proposed and tested experimentally and numerically resulting in a robust and highly sensitive design. The work presented here provides some of the first insights into multi-material fiber fabrication, an equation which provides an estimated relationship between magnetostrictive strain transfer onto a fiber optic core and the perceived DAS based sensor results, as well as a first of its kind multi-parameter distributed acoustic and magnetic field sensor.

One conventional method for studying dislocations uses the Transmission Electron Microscope (TEM), a complex and expensive piece of equipment which requires extensive specimen preparation in order to thin the specimens to electron transparent thickness. Newer High Resolution Electron Backscatter Diffraction (HREBSD) methods of determining geometrically necessary dislocation content via cross-correlation promise to be able to produce estimates of the dislocation density of the sample over a larger area with considerably less preparation time and using a much more accessible instrument. However, the accuracy of the new EBSD technique needs more experimental verification, including consideration of possible changes in the specimen dislocation density due to the different preparation methods. By comparing EBSD and TEM dislocation measurements of Electron Transparent platinum specimens prepared using the Focused Ion Beam (FIB), along with EBSD dislocations measurements of specimens prepared by both FIB and mechanical polishing techniques, this paper seeks to verify the accuracy of the new method and identify any changes in the specimens’ apparent dislocation density caused by the different preparation processes.

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<p>This thesis explores the ablation and texturing of synthetic single crystal diamond under ultrashort laser pulse irradiation in rough vacuum ambient conditions. Experiments were performed with a 1 kHz repetition rate titanium sapphire laser system producing pulses at 800 nm central wavelength and 150 fs pulse duration. First, the production of ordered periodic nanostructures (ripples) on the diamond surface was characterized and the periodicity of these structures was analyzed against irradiation parameters. Ripples were usually found to fall into one of two categories: one with a spatial period near the irradiation wavelength and one with a spatial period near λ/2n, where λ is the central laser wavelength in air and n is the refractive index of diamond at λ. The spatial periods were plotted against irradiation conditions including the peak fluence, number of incident pulses, and the angle of incidence. Unique outcomes arising out of complex irradiation conditions were also explored. Second, the ablation thresholds for single pulse up to 1000 pulse irradiation were determined using the <em>D</em>² method at both the fundamental central wavelength (800 nm) and the second harmonic (400 nm). The single 800 nm pulse ablation threshold for synthetic single crystal diamond was determined to be 2.3 J/cm² with an incubation coefficient of 0.54. The single 400 nm pulse ablation threshold was determined to be 1.5 J/cm² with an incubation coefficient of 0.73.</p> / Master of Applied Science (MASc)