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Multi-scale mechanical characterization of highly swollen photo-activated collagen hydrogelsTronci, G., Grant, Colin A., Thompson, N.H., Russell, S.J., Wood, David J. 11 1900 (has links)
Yes / Biological hydrogels have been increasingly sought after as wound dressings or scaffolds for regenerative medicine, owing to their inherent biofunctionality in biological environments. Especially in moist wound healing, the ideal material should absorb large amounts of wound exudate while remaining mechanically competent in situ. Despite their large hydration, however, current biological hydrogels still leave much to be desired in terms of mechanical properties in physiological conditions. To address this challenge, a multi-scale approach is presented for the synthetic design of cyto-compatible collagen hydrogels with tunable mechanical properties (from the nano- up to the macro-scale), uniquely high swelling ratios and retained (more than 70%) triple helical features. Type I collagen was covalently functionalized with three different monomers, i.e. 4-vinylbenzyl chloride, glycidyl methacrylate and methacrylic anhydride, respectively. Backbone rigidity, hydrogen-bonding capability and degree of functionalization (F: 16 ± 12–91 ± 7 mol%) of introduced moieties governed the structure–property relationships in resulting collagen networks, so that the swelling ratio (SR: 707 ± 51–1996 ± 182 wt%), bulk compressive modulus (Ec: 30 ± 7–168 ± 40 kPa) and atomic force microscopy elastic modulus (EAFM: 16 ± 2–387 ± 66 kPa) were readily adjusted. Because of their remarkably high swelling and mechanical properties, these tunable collagen hydrogels may be further exploited for the design of advanced dressings for chronic wound care.
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On the Characterization of Library CellsSulistyo, Jos Budi 01 September 2000 (has links)
In this work, a simplified method for performing characterization of a standard cell is presented. The method presented here is based on Synopsys models of cell delay and power dissipation, in particular the linear delay model. This model is chosen as it allows rapid characterization with a modest number of simulations, while still achieving acceptable accuracy. Additionally, a guideline for developing standard cell libraries for use with Synopsys synthesis and simulation tools and Cadence Placement-and-Routing tools is presented. A cell layout library, built in accordance with the presented guidelines, was laid out, and a test chip, namely a dual 4-bit counter, was built using the library to demonstrate the suitability of the method. / Master of Science
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Dielectric Characterization: A 3D EM Simulation ApproachSewall, Lyle Matthew 18 December 2006 (has links)
A new approach is presented that relies upon 3D electromagnetic simulation results to characterize the complex permittivity of homogeneous dielectric materials. By modeling the test fixture and obtaining a set of simulated S-parameters through an iterative solution process, the dielectric constant and loss tangent can be found. With further development, the 3D simulation results may be used to replace the need for complex theoretical analysis of the measurement geometry.
The method is applied to an X-band rectangular waveguide setup, for which the theoretical S-parameters can be readily calculated. A Teflon sample, for which the dielectric properties are well-known, is used for all measurements and calculations. After presenting a detailed derivation to obtain the theoretical S-parameters, the Teflon sample is measured and compared to the theoretical results, from which the comparison shows great promise. An inverse solution algorithm is used to solve for the material properties from the experimental S-parameters.
Low-frequency measurement of the Teflon sheet was performed by using a dielectric capacitor test fixture. The results show the effect of an air gap between the electrode and sample, producing serious errors. / Master of Science
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Technology for Designing the Steering Subsystem Component of an Autonomous VehicleBrown, William Shaler 15 October 2007 (has links)
Autonomous vehicles offer means to complete unsafe military operations without endangering the lives of soldiers. Such solutions have fueled many efforts towards designing autonomous, or unmanned, systems. Military and academic research efforts alike continue to focus on developing these systems. While many different autonomous vehicles have been introduced, however, such complex systems have limited drive-by-wire operability. The complete process to up-fit a vehicle to fully autonomous operation involves the design, up-fit, testing and verification of many different subsystems. The objective of this thesis is to design and model an autonomous steering system requiring little modifications to an existing steering system. It is desirable to still operate the vehicle manually as well as preserve the vehicle's visual appearance. Up-fit and implementation of the designed steering system and verification of its functionality has been documented as well. Utilization of the supplied controller and software has enabled the testing and characterization of the system. The proposed design offers a solution to a wide variety of wheeled vehicles steered via the traditional and common steering wheel method. In addition, modifications have been made to an existing simulation of an unmanned vehicle in a military testbed environment (Fort Benning). The simulation accounts for the control methodology as it has been designed and tested with, which offers the ability to analyze the dynamics of the unmanned system. / Master of Science
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Plot and Characterization in the First and Second Series of Galdos' Episodios NacionalesMason, Harrell 06 1900 (has links)
This thesis, then, has evolved out of the need for such study and will deal specifically with the novels of the first two series of the Episodios Nacionales. It will be an attempt to present a preliminary survey of the most important characters, both major and minor, to present a composite picture of the story and plots within the two series of novels, and to indicate the relation of the influences pointed out in the preceding pages.
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Characterization in Valle-Inclan's NovelsHardin, Robert Joseph 01 1900 (has links)
This thesis covers a biography and principal influence of Valle-Inclan, the Sonata novels, Carlist war novels, the Comedias Barbaras, and Flor de Santidad and Tirano Baderas.
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In Vitro Electrochemical Evaluation of Bioelectronic ArraysSingh, Sukhpreet 12 1900 (has links)
In this paper, I sought to identify and develop a protocol on electrode arrays as a result of rapid aging by applying rapid current over time. We, however, apply a different approach by using phosphate buffer solution (PBS) to mimic the conditions of the body. Here we have established an in vitro protocol for accelerated aging, a process that involves testing in extreme conditions such as oxygen, heat, sunlight, humidity, and vibration aimed at speeding the normal aging process of items; on commercially available shape memory polymer electrode arrays from Qualia over a period of 30 days in PBS. Two electrode arrays were placed in 37°C and 2 were placed in 57°C. Open lead electrochemical impedance spectroscopy (EIS) was conducted on the electrode arrays. Overall, the results showed there were differences in average impedance during this accelerated aging protocol. At 37°C we see that the average impedance values increased as the electrodes were aged at 1kHz from an average of 4.15E6 to 9.14E6 Ohms. At 57°C electrode arrays 4 and 5 showed strong P values well above 0.05, but average impedance increased drastically from 3.27E6 to 9.97E6 and P value of 0.04 from measurement day 24 to day 30. This indicated to us that the electrode could be experiencing some delamination. In addition, this could be because the Qualia nerve cuffs tested were "B" grade, so changes in impedance could be due to the integrity of the device. This would tell us that these electrode arrays would not be capable to withstand long – term recording for up to 240 days. As a result, rejecting the hypothesis that this protocol would show no change in impedance levels for a simulated aging period of 240 days. Although this protocol was not in a perfect setting and the quality of the electrodes were not up to standard, this gave us insight into the electrochemical properties of SMP electrodes which will be useful when we bio-fabricate our own electrodes to study gastrointestinal (GI) disorders.
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Synthesis, characterization, and reactivity of niobium perfluoropinacolate complexesDel Rosario, Cathlene Nicole Balacanao 10 February 2025 (has links)
2024 / Six new niobium complexes supported by bidentate dianionic perfluoropinacolate, ({OC(CF3)2}2)2-, denoted as pinF, have been synthesized and fully characterized: [Nb(NMe2)(NHMe2)(pinF)2] (1), (Me2NH2)[Nb(pinF)3] (2), {K(THF)3}[Nb(pinF)3] (3), {K(THF)3}2[Nb2(μ2-O)2(pinF)4] (4), {K(18C6)(THF)2}2[Nb2(μ2-O)2(pinF)4] (5), and {K(MeCN)7/3}3[Nb2(μ2-O)2(pinF)4] (6). Complex 1 exhibits fluxionality of monodentate and bidentate ligands; various methods of recrystallization repeatedly provided solid-state evidence of a cis isomer (1-cis), while VT 1H and 19F and 2D 19F NMR provided solution-state evidence of a trans isomer (1-trans). The twist angles of 2 and 3 range from 28.87° to 32.17°, classifying the complexes as an intermediate between trigonal prismatic and octahedral geometry. The 18-crown-6 encapsulation of K+ countercations of 5 elongate the Nb–O bond distances compared to those of 4; the K+ countercations of 4 exhibit multiple K⋯F and K⋯O interactions with the four chelating pinF ligands. Each of the soluble, {Nb5+(pinF)} complexes exhibit solution-state 93Nb NMR resonance features that support previous 93Nb NMR measurements made with static/MAS methods.
The heteroleptic complex 1 was found to selectively dehydrate 2° and 3° alcohols to alkenes, historically observed by analogous insoluble niobium pentoxide (Nb2O5) and niobic acid (Nb2O5⋅nH2O). The dehydration of 1-phenylethanol to styrene under mild conditions exhibited no evidence for polymerization to styrene. Both 2° and 3° alcohol dehydration studies gave no evidence of condensation products. The transformation of 1 during dehydration was proposed from 1H, 19F, and 93Nb NMR spectroscopy.
Cyclic voltammetry was used to determine the electrochemical reduction and oxidation potential of Nb5+/4+ in the all-O-donor environments of 2, 3, 4, and 5. Despite observing E½ = -1.303 V of 2 and E½ = -1.263 V of 3 (both in MeCN), the Nb5+ center could not be reduced in the tris-pinF complex. One-electron reduction of the {Nb2(μ2-O)2(pinF)4} dimer formed the mixed-valent complex {K(MeCN)7/3}3[Nb2(μ2-O)2(pinF)4], which was the first crystal structure of Nb in all-O-donor environment: (1) in a formal oxidation state lower than 5+ and (2) in a coordination number lower than eight. The solid-state SCXRD and in silico DFT data point to 6 as a Robin-Day Class II dimer, and additional experiments with the dimer in solution for UV-Vis and Evans method suggest electronic communication between the two Nb centers.
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Understanding the Origins of Bioadhesion in Marine OrganismsAndres M Tibabuzo Perdomo (6948671) 16 August 2019 (has links)
<p>Curiosity is a powerful tool, and combined with the ability to observe the natural world, grants humankind an unique opportunity, the opportunity to wonder why. Why do things exist?, why do they do the things they do?, why is this even possible?</p>
<p>Research in our lab is focused on the basic understanding and potential application of biological materials, in particular, biological adhesives produced by marine organisms such as oysters. Oysters produce a cement-like material that is able to withstand the dynamic conditions found in coastal environments. The focus of this dissertation is to lay the basis of the characterization of new biological materials by observing and analyzing its physical properties, to measure the performance of the material in natural conditions and finally to identify the basic components that give the material the properties that we observe. The end goal of this project is to understand the properties of this material so we are able to develop a synthetic system that is able to imitate, as close as possible, what we find in nature. These results, and more importantly, the new questions that emerge from this research, provide a first look at the adhesive system of oysters leading the way to new discoveries in the future.</p>
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Méthodologies statistiques pour le recueil et l’analyse de données de caractérisation de grands ensembles de stimuli - Application à la caractérisation sensorielle de produits & à la caractérisation de gestes culinaires / Statistical methodologies for the collection and analysis of data characterizing large sets of stimuli – Application to the sensory characterization of products & to the characterization of culinary techniquesBrard, Margot 21 January 2019 (has links)
Dans le secteur agroalimentaire, la caractérisation des gestes culinaires est considérée de plus en plus comme un levier d’innovation. En observant et en analysant la manière avec laquelle leurs produits sont appréhendés en cuisine par les usagers (consommateurs ou professionnels), les industriels peuvent en effet déceler des pistes d’amélioration ou des idées de nouveaux produits.Dans ce travail de recherche, nous proposons de nouvelles méthodes dédiées à la caractérisation des gestes culinaires. Leur caractère innovant repose sur le fait qu’elles relèvent d’une approche quantitative, et non d’une approche qualitative comme cela est usuellement le cas. Elles s’inspirent en partie de deux méthodes de caractérisation utilisées en analyse sensorielle : le tri libre et la Q-méthodologie binaireNous voyons comment des développements méthodologiques apportés à ces dernières permettent de caractériser des grands ensembles de stimuli. Ces développements sont liés à la fois à la procédure de recueil des données et à la procédure d’analyse statistique des données.En particulier, nous proposons plusieurs procédures statistiques permettant d’aborder des problématiques variées : l’analyse d’un ensemble de partitions contenant des données manquantes, la classification non supervisée de profils d’évaluations binaires basée sur la notion d’accord inter-évaluateurs, etc.Nous voyons ensuite que les deux méthodes de caractérisation quantitatives ‘améliorées’ sont applicables à des gestes culinaires / In the agri-food sector, the characterization of culinary techniques - through their observation and analysis - is increasingly seen as a lever for innovation. By analyzing how their products are used in the kitchen by the users (consumers or professionals), the manufacturers can detect improvement tracks or ideas for new products.In this research, we propose new methods dedicated to the characterization of culinary techniques. Their innovative nature is based on the fact that they are based on a quantitative approach, and not on a qualitative approach as is usually the case. They partially draw their inspiration in two methods of characterization used in sensory analysis: the free sorting and the binary Q-methodologyWe see how methodological developments brought to the latter make it possible to characterize large sets of stimuli. These developments are both related to the procedure of data collection and to the procedure of statistical analysis of the data. In particular, we propose several statistical procedures to address various issues: the statistical analysis of a set of partitions containing missing data, the unsupervised agreement-based clustering of a set of profiles of binary evaluations, etc.Then, we see that these two 'improved' quantitative methods of characterization can be successfully applicable to culinary techniques.
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