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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 57 for “"COF"”.
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Novel covalent organic framework (COF) thin-film composite nanofiltration membrane for effective removal of organic compounds from petroleum produced water
… layer made with a covalent organic framework (COF) developed in the early phases of this study was used to investigate its rejection capability for organic model compounds present in treated produced water. Permeation experiments with the COF membrane resulted in 60-70% rejection for three …
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A Polynomial Chaos Approach for Stochastic Modeling of Dynamic Wheel-Rail Friction
… estimation of the coefficient of friction (CoF) is essential to accurately modeling railroad dynamics, reducing maintenance costs, and increasing safety factors in rail operations. The assumption of a constant CoF is popularly used in simulation studies for ease of implementation, however …
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Pilot Perception of Cockpit Organizational Framework’s Impact on Flight Safety and Subordinate Pilot Behavior
… of the impact cockpit organizational framework (COF) has on both flight safety and subordinate pilot behavior. Six research questions asked if the COF used in determining pilot positional assignments is perceived as having an impact on flight safety and subordinate pilot behavior. It was …
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Design and dynamic simulation of mobile manipulators incorporating tribological analysis of 16MnCr5 and EN19 steels.
… to determine the coefficient of friction (COF) for two contact geometries - sliding cylinder and sliding pin, selected as approximations of manipulator joint contact. Oil lubricant was used to generate reference COF characteristics against which COF of grease-lubricated contacts were …
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Modeling Nanofiltration Separation Mechanisms in Covalent Organic Framework Membranes
… this work, we apply covalent organic frameworks (COFs) as model NF membrane materials to demonstrate control over partitioning and transport mechanisms. We experimentally isolate and quantify steric and non-steric contributions to solute partitioning and transport in NF via application of the …
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Design, Synthesis, Characterization, and Evaluation of Boronate Ester-Linked Porous Materials: Covalent Organic Frameworks and Polymers of Intrinsic Microporosity
… series of alkylated covalent organic frameworks (COFs), insight into the influence of alkylation in the hexagonal COF pores on the hydrolytic stability of the B-O linkages led to development of a family of hybrid COFs (HCOFs). These HCOFs were made by incorporating a gradual ladder of alkylation …
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Study of Porous Materials Incorporating Boronate Esters
<p> COF-18Å is one type of Covalent Organic Framework (COF) that incorporates self-assembling covalent bonded boronate esters as secondary building units to form a porous material. COF-18Å has the ability to store gases, high surface areas, good thermal stability, but is susceptible to hydrolysis. …
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Using Radar and Seismic Methods for the Determination of Ice Column Properties and Basal Conditions at Jakobshavn Isbræ and the NEEM Drill Site
… of preferred crystal orientation fabrics (COF) within the ice column can have a strong influence on the flow behavior of an ice sheet or glacier. Typically, COF information comes from ice cores. Observations of anisotropic seismic wave propagation and backscatter variation as a function of …
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Scalable Synthesis and Separation Performance of Covalent Organic Framework and Contorted Polyamide Membranes
… polymerization. Covalent organic framework (COF) based TFC membranes are a new class of membrane materials ideal for NF applications, and specifically organic solvent nanofiltration (OSN), because of their crystalline, highly porous structures and chemical and thermal stability. Contorted …
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Scalable Synthesis and Separation Performance of Covalent Organic Framework and Contorted Polyamide Membranes
… polymerization. Covalent organic framework (COF) based TFC membranes are a new class of membrane materials ideal for NF applications, and specifically organic solvent nanofiltration (OSN), because of their crystalline, highly porous structures and chemical and thermal stability. Contorted …
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Development and physicochemical characterization of thin-film composite nanofiltration membranes with covalent organic framework active layers
… In contrast, covalent organic frameworks (COFs) are an emerging class of materials that offer exceptional opportunities to overcome these challenges. COFs are constructed from modular building blocks to form crystalline, permanently porous materials. Employing two-dimensional (2D) COF …
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Fundamental Understanding of Palladium-Based Catalysts: From Pyrene-Based COFs to Size-Controlled Bimetallic Nanostructures
… chemical behavior. Covalent organic frameworks (COFs), a class of porous and crystalline materials composed of light elements (H, B, C, N, and O), are attractive supports for SACs due to their designable periodic structures and stable covalent bonding. These frameworks offer uniform and tunable …
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THE EFFECT OF MAGNESIUM CARBONATE (CHALK) ON GEOMETRIC ENTROPY, FORCE AND EMG DURING ROCK CLIMBING
… between the hands and the surface of the rock (COF<sub>H</sub>). The purpose of this study was to assess whether or not chalk affects geometric entropy (GE) or muscular activity during rock climbing. Participants were asked to complete a predesigned movement sequence with and without the use of …
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ADVANCED POROUS MATERIALS IN MIXED MATRIX MEMBRANES FOR CARBON DIOXIDE CAPTURE
… nanosheets, MOF@covalent organic framework (COF) hybrid nanoparticles, three dimensional COF nanoparticles, have been explored as potential fillers in MMMs to further enhance the separation performance of pure polymeric membranes. These works will shed lights on the design and preparation of …
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Design of Tribologically Enhanced Polymeric Materials for Biomedical Applications
… is characterized by the coefficient of friction (COF). Friction is one of the primary subjects of interest in tribology, the science of the friction and wear of articulating surfaces.</p> <p>A number of fascinating tribological systems can be found in nature. One example which has drawn a …
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Clustering based causal topic mining
… clustering based algorithms - cCTM-CF and cCTM-CoF to generate causal topics. We evaluate these algorithms both qualitatively, and quantitatively by comparing their coherence and correlation scores to that of the baseline generative causal topic model - gCTM. We found that cCTM-CoF performs 35% …
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Ceramic composites with solid lubricants processed by pulsed electric current sintering
… nanosized grain structure of the matrix. The CoF of the hard matrix was reduced by 20 – 24 % at 25 °C and by 60 – 65 % at 400 °C. Improvement in friction properties of Al2O3 matrix was limited at 25 °C when modified by Mo. At 400 °C, the CoF of the composite, when compared to alumina, was …
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Molecularly thin rheological and contact interfaces
… HfBN exhibited lower coefficient of friction (COF) compared to the multilayer HfB2/HfBN. The amorphous as-deposited films were subjected to annealing at 700 oC in order to study their mechanical properties in the post-treatment conditions. In comparison to as-deposited films the annealed films …
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Surface Engineering and Characterization of Laser Deposited Metallic Biomaterials
… wear with higher coefficient of friction (COF). Using 440C stainless steel balls drastically improved the COF of as deposited TNZT+2B and seemed to eliminate the effect of “three body abrasive wear,” and also exhibited superior wear resistance than Ti-6Al-4V.
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A Collapsing Result Using the Axiom of Determinancy and the Theory of Possible Cofinalities
… that J<λ+(a) (the ideal of sets which force cof Π α < λ) is generated from J<λ+(a) by adding a singleton. Combining these results with a polarized partition relation on ω1
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