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Altronegest influences growth, reproductive, and carcass traits in male swineKluber, Edward Frank. January 1986 (has links)
Call number: LD2668 .T4 1986 K58 / Master of Science / Animal Sciences and Industry
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Interferometric Synthetic Aperture Sonar Signal Processing for Autonomous Underwater Vehicles Operating Shallow WaterGiardina, Patricia E 15 December 2012 (has links)
The goal of the research was to develop best practices for image signal processing method for InSAS systems for bathymetric height determination. Improvements over existing techniques comes from the fusion of Chirp-Scaling a phase preserving beamforming techniques to form a SAS image, an interferometric Vernier method to unwrap the phase; and confirming the direction of arrival with the MUltiple SIgnal Channel (MUSIC) estimation technique. The fusion of Chirp-Scaling, Vernier, and MUSIC lead to the stability in the bathymetric height measurement, and improvements in resolution. This method is computationally faster, and used less memory then existing techniques.
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Ferromagnetic Resonance Studies of Coupled Magnetic SystemsAdams, Daniel J. 13 May 2016 (has links)
The high-frequency properties of coupled magnetic systems have been investigated using vector network analyzer ferromagnetic resonance (VNA-FMR) spectroscopy. SAF structures consist of two ferromagnetic layers separated by a non-magnetic spacer, coupled through the indirect exchange interaction. The ferromagnetic layers of our samples were composed of FeCoB separated by a layer of Ru. The thickness of Ru was varied in the range of 8 to 18 Å among the samples studied. Antiferromagnetic coupling can be quickly identified by the major hysteresis loop (MHL).
A new way of displaying FMR data for these trilayer samples is presented which completely preserves the anisotropy effects while fully characterizing the angular dependence of FMR. The advantage of our representation is that the high-frequency data can be easily compared to the static switching behavior at any angle obtained through susceptibility measurements.
Ferromagnetic resonance; Coupled; Synthetic antiferromagnet; Magnetization switching
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On the estimation of physical roughness of sea ice in the Canadian Arctic archipelago using synthetic aperture radarCafarella, Silvie 29 August 2019 (has links)
Sea ice surface roughness is a geophysical property which can be defined and quantified on a variety scales, and consequently affects processes across various scales. The sea ice surface roughness influences various mass, gas, and energy fluxes across the ocean-sea ice-atmosphere interface. Utilizing synthetic aperture radar (SAR) data to understand and map sea ice roughness is an active area of research. This thesis provides new techniques for the estimation of sea ice surface roughness in the Canadian Arctic Archipelago using synthetic aperture radar (SAR). Estimating and isolating sea ice surface properties from SAR imagery is complicated as there are a number of sea ice and sensor properties that influence the backscattered energy. There is increased difficulty in the melting season due to the presence of melt ponds on the surface, which can often inhibit interactions from the sensor to the sea ice surface as shorter microwaves cannot penetrate through the melt water. An object-based image analysis is here used to quantitatively link the winter first-year sea ice surface roughness to C-band RADARSAT-2 and L-band ALOS-2 PALSAR-2 SAR backscatter measured at two periods: winter (pre-melt) and advanced melt. Since the sea ice in our study area, the Canadian Arctic Archipelago, is landfast, the same ice can be imaged using SAR after the surface roughness measurements are established. Strong correlations between winter measured surface roughness, and C- and L-band SAR backscatter acquired during both the winter and advanced melt periods are observed. Results for winter indicate: (1) C-band HH-polarization backscatter is correlated with roughness (r=0.86) at a shallow incidence angle; and (2) L-band HH- and VV-polarization backscatter is correlated with roughness (r=0.82) at a moderate incidence angle. Results for advanced melt indicate: (1) C-band HV/HH polarization ratio is correlated with roughness (r=-0.83) at shallow incidence angle; (2) C-band HH-polarization backscatter is correlated with roughness (r=0.84) at shallow incidence angle for deformed first-year ice only; and (3) L-band HH-polarization backscatter is correlated with roughness (r=0.79) at moderate incidence angle. Retrieval models for surface roughness are developed and applied to the imagery to demonstrate the utility of SAR for mapping roughness, also as a proxy for deformation state, with a best case RMSE of 5 mm in the winter, and 8 mm during the advanced melt. / Graduate
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Investigation of electronic properties of high purity synthetic single crystal type IIa diamond for electronic applicationsCosta, A.M.O.D. da 19 June 2008 (has links)
Abstract
A range of di®erent high-quality single crystal diamonds synthesized under high
pressure and high temperature (HPHT) conditions have been studied in view of their
potential as candidates for specialized electronic devices with emphasis on particle
detectors. The studies incorporated a long range of spectroscopic and electronic
characterization techniques.
Special attention was given to electronic properties and device performance re-
lated to the electrical contacts applied, the type and the concentration of impur-
ities and the crystallographic defects present. The electronic response of a dia-
mond detector as far as impurities are concerned is predominantly determined
by the single substitutional nitrogen (SSN) and boron acceptors. Di®erent tech-
niques were used to assess the role of such impurities in the diamond crystals stud-
ied, as well as to study the dynamics due to the interaction of such impurities
with each other (compensation). Hence, the electron spin resonance (ESR) and the
current-deep level transient spectroscopy (I-DLTS) techniques were used in this re-
spect to extract the information concerning activation energies, nitrogen-boron dy-
namics, and the nitrogen and boron concentrations.
ii
iii
It was found that the SSN content was below 1013 cm¡3 with this result giving the
approximate concentration of boron acceptors, being the same value as of that of
the SSN, or slightly above. Maximum activation energies of boron acceptors were
extracted from three di®erent regions in the bulk of the diamond. The values were
approximately 0.311 eV § 0.0027 eV in the center region, 0.308 eV § 0.007 eV in
the intermediate region and 0.29 eV § 0.007 eV at the edge region, respectively.
The maximum activation energy when boron is fully compensated is about 0.37 eV.
Properties of ohmic and Schottky contacts as a function of concentration of SSN and
boron acceptors were investigated using Current-Voltage characteristic and photo-
current measurements. Di®erent surface treatment conditions and di®erent types of
diamonds (IIa, IIb and Ib) were used.
Electronic properties as a function of contacts were assessed for high purity synthetic
type IIa diamond detector, incorporating a time of °ight (TOF) UV laser set-up.
The maximum hole collection distance at room temperature was found to be 91.00
cm, the maximum transient time for holes was about 1.00 ms and the e±ciency was
approximately 41%, with contacts made of Ti/Pt/Au-Ru. When Ru-Ru contacts
are applied, the maximum hole mobility and the velocity were extracted at room
temperature to be about 17963.44 cm2V¡1s¡1 and 5.02 £107 cms¡1, respectively,
and the e±ciency of the device is about 30%. The maximum applied external
electric ¯elds with Ru-Ru contacts were increased to about 1.32 times that at low
temperature and to about 1.84 times that at room temperature.
iv
Large signals generated by ®-particles from 228Th were obtained without using amp-
li¯cation. However, a full analysis of the pulse was not possible due to the narrow
bandwidth of the electronic probes used.
In a detector made of type Ib diamond, with SSN concentrations of about 50 ppm,
it was found that regions in the bulk exhibiting better charge collection properties
contained small concentrations of uncompensated boron impurity. On the other
hand, the di®erence in the concentrations of SSN between the two type Ib diamonds,
with about 50 ppm and about 200 ppm of SSN concentrations, respectively, resulted
in approximately 70 ps di®erence in the transit time between two detectors made of
these diamonds.
Keywords:
Synthetic diamond, detector, HPHT, type Ib, type IIa, single substitutional ni-
trogen, SSN, ESR, ARP, I-DLTS, metallization, uncompensated boron impurity,
crystallographic defects, rise and decay times, charge carrier life time, charge carrier
mobility, carrier mean free path , charge collection distance, carrier Schubweg.
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Investigation of nanoscale reinforcement into textile polymersUnknown Date (has links)
A dual inclusion strategy for textile polymers has been investigated to increase elastic energy storage capacity of fibers used in high velocity impact applications. Commercial fibers such as Spectra and Dyneema are made from ultra high molecular weight polyethylene (UHMWPE). Dynamic elastic energy of these fibers is still low therefore limiting their wholesale application without a secondary metallic or ceramic component. The idea in this investigation is to develop methodologies so that the elastic energy of polyethylene based fibers can be increased by several folds. This would allow manufacturing of an all-fabric system for high impact applications. The dual inclusion consists of a polymer phase and a nanoscale inorganic phase to polyethylene. The polymer phase was nylon-6 and the inorganic phase was carbon nanotubes (CNTs). Nylon-6 was blended as a minor phase into UHMWPE and was chosen because of its large fracture strain - almost one order higher than that of UHMWPE. On the other hand, CNTs with their very high strength, modulus, and aspect ratio, contributed to sharing of load and sliding of polymer interfaces as they aligned during extrusion and strain hardening processes. A solution spinning process was developed to produce UHMWPE filaments reinforced with CNTs and nylon-6. The procedure involved dispersing of CNTs into paraffin oil through sonication followed by dissolving polymers into paraffin-CNT solution using a homogenizer. The admixture was fed into a single screw extruder for melt mixing and extrusion through an orifice. The extrudate was rinsed via a hexane bath, stabilized through a heater, and then drawn into a filament winder with controlled stretching. In the next step, the as produced filaments were strain-hardened through repeated loading unloading cycles under tension. / Neat and reinforced filaments were characterized through DSC (Differential Scanning Calorimetry), XRD (X-ray Diffraction), Raman Spectroscopy, SEM (Scanning Electron Microscope), and mechanical tests. Phenomenal improvement in properties was found; modulus, strength, fracture strain, and elastic energy increased by 219%, 100%, 107% and 88%, respectively before strain hardening. Once strain hardened the strength, modulus and elastic energy increased by almost one order of magnitude. Source of these improvements were traced to increase in crystallinity and rate of crystallization, formation of microdroplets as a minor phase, sliding between minor and major phases, coating of nanotubes with polymer and alignment of nanotubes. / by Mujibur Rahman Khan. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
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Élargissement du spectre de résistance aux potyvirus : utilisation de la plante modèle Arabidopsis thaliana / Enlargement of plants resistance spectrum to RNA viruses using the Arabidopsis thaliana plant modelBastet, Anna 22 November 2018 (has links)
Pour lutter contre les maladies virales chez les plantes cultivées, il est important de développer des résistances génétiques. Dans ce contexte, les facteurs d’initiation de la traduction eIF4E jouent un rôle majeur dans la mise en place de résistance aux potyvirus, un groupe de virus à ARN nuisible pour les cultures. Fréquemment, des allèles naturels de résistances ont été sélectionnés dans les espèces à intérêt agronomique. Cependant, nombreuses sont les espèces ne possédant pas de résistance naturelle. Pour remédier à ce problème, j’étudie lors de ma thèse le pathosystème Arabidopsis thaliana-potyvirus afin d’élaborer de nouvelles sources de résistances, en vue d’étendre leur application aux plantes cultivables. Pour ceci, je crée artificiellement par mutagénèse dirigée des allèles de résistances dont je teste dans la plante la fonctionnalité ainsi que l’efficacité vis-à-vis de la résistance. En combinant ces allèles de résistance synthétiques avec d’autres résistances liées aux facteurs eIF4E, je vise à élargir le spectre de résistance aux potyvirus ainsi qu’à augmenter la durabilité de ces résistances. Cette étude permettra de prouver la faisabilité de ce système pour obtenir des plantes à large spectre de résistance avant de pouvoir ainsi l’appliquer aux plantes à intérêt agronomique. / The development of genetic resistance is important to avoid viral infections in cultivated crops. In this context, translation initiation factors eIF4E have a major role in resistance to potyviruses, a family of viruses damageable to crops. Although natural resistance alleles are often used in crops breeding, there are still species devoided of such natural resistance, making it impossible to develop genetic resistance. Using the Arabidopsis thaliana-potyviruses pathosystem, I aim at developing new sources of resistances as a proof of concept before considering their application to crop species. For this, I am developing artificial resistance alleles created by directed mutagenesis before testing them for both their functionality and their resistance efficiency in plants. By combining these synthetic resistance alleles with others eIF4E factors-mediated resistance, my aim is to enlarge resistance spectrum to potyviruses as well as to increase the resistance durability. This study will make proof of the feasibility of this system to obtain large spectrum resistance plants with the perspective of extending it to cultivated plants.
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The Synthesis of Functionalized Cycloparaphenylenes as Novel Biocompatible Fluorescent Probes and Organic MaterialsWhite, Brittany 30 April 2019 (has links)
Conjugated macrocycles have emerged as novel structural motifs that modulate the electronic properties of organic molecules because of their strained and contorted structures. Cycloparaphenylenes, known as nanohoops, are a particularly attractive scaffold for the design of new types of carbon nanomaterials because of their size-selective synthesis, radially oriented π-systems and tunable electronic properties. The development of modular syntheses of nanohoops over the past decade should enable the preparation of substituted derivatives that can be tuned for applications in biology and materials science.
Chapter I provides a brief overview of conjugated macrocycles recently reported in the literature with a discussion of the structural effects that are responsible for the remarkable properties of this class of molecules. Chapter II highlights a scalable and mild synthetic approach developed in our lab to prepare nanohoop conjugated macrocycles and expands the generality of this methodology with the formal synthesis of natural product Acerogenin E. Chapter III describes the synthesis of cycloparaphenylenes with versatile functional handles and uncovers the reactivity of the strain nanohoop backbone under reaction conditions that promote the formation of radical cations. Chapter IV takes advantage of the functional groups described in chapter III to develop the first example of nanohoops as a new class of biocompatible fluorophores. Chapter V details a novel synthetic approach that enables the incorporation of the linear acene pentacene into the nanohoop backbone and reports our findings on the impact that the macrocyclic structure has on the properties of this organic semiconductor. In summary, the findings discussed in this dissertation provide synthetic strategies for the selective functionalization of nanohoops and highlight this class of molecules as a novel scaffold for the design of new types of carbon nanomaterials.
This dissertation includes previously published and unpublished co-authored material.
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Synthetic Fiber Reinforced Concrete in Marine Environments and Indirect Tension TestUnknown Date (has links)
An experiment was conducted to evaluate the durability, toughness, and strength
of Synthetic Fiber Reinforced Concrete after being immersed in five separate
environments for one year at FAU SeaTech. The specimens were molded and reinforced
with two-inch Polypropylene/Polyethylene Fibers in a concrete aggregate matrix and
were cut into identical sizes. Some of these environments had accelerated parameters
meant to increase degradation to simulate longevity and imitate harsh environments or
seawater conditions. The environments consisted of: a high humidity locker (ideal
conditions), submerged in the Intracoastal Waterway (FAU barge), seawater immersion,
a wet and dry seawater immersion simulating a splash/tidal zone, and another in low pH
seawater. The latter three were in an elevated temperature room (87-95°F) which
produced more degradative properties. The specimens were monitored and the
environments were controlled. The specimens were then evaluated using the IDT test
method using force to initiate first-cracking and post-cracking behaviors. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
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Using Synthetic Biology to Create a Safe and Stable Ebola Surrogate for Effective Development of Detection and Therapy PlatformsUnknown Date (has links)
Ebolavirus is responsible for a deadly hemorrhagic fever that has claimed thousands of
lives in Africa and could become a global health threat. Because of the danger of
infection, novel Ebola research is restricted to BSL-4 laboratories; this slows progress
due to both the cost and expertise required to operate these laboratories. The development
of a safe surrogate would speed research and reduce risk to researchers.
Two highly conserved Ebola gene segments—from the glycoprotein and
nucleoprotein genes—were designed with modifications preventing expression while
maintaining sequence integrity, spliced into high copy number plasmids, cloned into
E.coli, and tested for stability, safety, and potential research applications. The surrogates
were stable over 2-3 months, had a negligible mutation rate (<0.165% over the
experiment), and were detectable in human blood down to 5.8E3-1.17E4 surrogates/mL.
These protocols could be used to safely simulate other pathogens and promote infectious
disease treatment and detection research. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
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