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- Lignin oxidation (2)
- Paper coatings (2)
- Sulfate pulping process (2)
- Thin films (2)
- Wood-pulp chemistry (2)
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- AHFID Project (1)
- Adhesive performance (1)
- Adsorption equilibrium measurement (1)
- Analog-to-Digital Converters (ADCs) (1)
- Anisotropy (1)
- Arsenic in drinking water (1)
- Arsenic transformation (1)
- Auxin (1)
- Bandwidth (1)
- Building Protection (1)
- CGWAVE model (1)
- Calibration (1)
- Carbon-carbon composites (1)
- Channel fading (1)
- Chemical vapor deposition (1)
- Chitosan flakes (1)
- Coastal surface water wave models (1)
- Commercial food crops (1)
- Communication links (1)
- Composite materials testing (1)
- Composite technology (1)
- Compression testing (1)
- Dynamic response (1)
- E-glasdvinyl ester composite specimens (1)
- Elasticity (1)
Articles 1 - 26 of 26
Full-Text Articles in Engineering
Mechanisms Of Print Gloss Development With Controlled Coating Structure, Sung Jai Jeon
Mechanisms Of Print Gloss Development With Controlled Coating Structure, Sung Jai Jeon
Electronic Theses and Dissertations
Paper gloss and print gloss have long been the subject of research because of their strong influence on end-use performance such as image clarity, contrast, and resolution. This work focuses on the significance of the structural factors of porous coatings on print gloss development in a systematic way to elucidate the governing mechanisms. The coating roughness, porosity, and pore size were the three experimental variables. Generation of well defined model coating structures was a challenge and required the appropriate combinations of pigment, binder, and calendering conditions. Calendering techniques with rough substrates (polyester films) were found to produce various rough surfaces …
Platinum/Silica Thin Films By Chemical Vapor Deposition, Tyler Philip Martin
Platinum/Silica Thin Films By Chemical Vapor Deposition, Tyler Philip Martin
Electronic Theses and Dissertations
Composite thin films consisting of platinum and silica (SiO)2 have been fabricated by chemical vapor deposition (CVD). These films were studied for possible future use in enhancing the selectivity of sensors for the chemical warfare agent sarin. Chemical vapor deposition is a thin film growth technique in which precursor molecules are carried into a reactor and decomposed, often at high temperature, to produce a thin solid film. A new cold wall CVD reactor was built for this work. The platinum precursor used in this work was platinum acetylacetonate [Pt(acac)2] and the silica precursor was tetraethoxysilane (TEOS). It …
Application Of Raman Techniques For Paper Coatings, Shivashanker Bitla
Application Of Raman Techniques For Paper Coatings, Shivashanker Bitla
Electronic Theses and Dissertations
Paper coatings are mixtures of pigments, binders and other additives used to improve the optical and printing properties of paper. During application, particle migration may occur resulting in a non-uniform distribution of pigments and binders. This may influence product quality. Raman spectroscopy is a potential tool to characterize coatings in terms of pigment/binder and pigment/pigment distribution. However, there is little work reported on this topic. Various coatings were applied to model substrates, dried and analyzed with Raman spectroscopy. CaC03 pigment and Styrene Butadiene latex binders are easy to detect and monitor in paper coatings when kaolin clays are not …
Development And Application Of The Zero Length Column (Zlc) Technique For Measuring Adsorption Equilibria, Federico Brandani
Development And Application Of The Zero Length Column (Zlc) Technique For Measuring Adsorption Equilibria, Federico Brandani
Electronic Theses and Dissertations
This thesis reports the results of an experimental study aimed at developing the "zero length column" (ZLC) method as a useful technique for measuring adsorption equilibria. In a ZLC experiment a small sample of adsorbent is pre-equilibrated with the sorbate, at a known partial pressure, in a He carrier. Information concerning the sorption kinetics and equilibria can be obtained fkom the desorption curve when the flow is switched to a pure He purge under carefully controlled conditions. This technique has been widely used to measure intraparticle diffusivities but, when operated at sufficiently low flow rate, it provides a simple and …
Pulp Pretreatments For Improved Selectivity And Extended Oxygen Delignification, Zheng Dang
Pulp Pretreatments For Improved Selectivity And Extended Oxygen Delignification, Zheng Dang
Electronic Theses and Dissertations
Oxygen delignification has developed steadily since it was introduced commercially in 1970 in South Africa and virtually all new fiber lines incorporate an oxygen delignification system following the digester prior to the bleach plant. Currently, the degradation of cellulose and consequently the loss of pulp strength limit the drop in kappa number that can be obtained using an oxygen process. Pulp selectivity, given by the selectivity coefficient (α), relates the reduction in the molecular weight of cellulose to the reduction in the ligin content of the pulp when measured by the kappa number. An evaluation of selectivity of deligification data …
Stabilization Of Rutile-Related Thin Film On Tio2 Substrates, Youngnam Cho
Stabilization Of Rutile-Related Thin Film On Tio2 Substrates, Youngnam Cho
Electronic Theses and Dissertations
Conducting metal oxide thin films are of broad interest because they have a wide variety of magnetic and electronic properties. Materials exist that range from superconducting to insulating, are ferromagnetic and are ferroelectric. These properties make thin conducting oxide films attractive for many industrial applications. A class of metal oxides exists that adapt the rutile crystal structure; the structure of the mineral rutile, TiO2. These metal oxides have the general formula MO2 where M is a metal cation of valence +4. Metal oxides crystallizing in the rutile structure also display a wide variety of physical properties. The …
Effect Of Kraft Pulping On Oxygen Delignification, Haixuan Zou
Effect Of Kraft Pulping On Oxygen Delignification, Haixuan Zou
Electronic Theses and Dissertations
The objective of the study reported here was to investigate experimentally the effect of the major Kraft pulping variables on the response of brownstock pulps to medium consistency oxygen delignification. Kraft pulping was performed on mixed Northeastern hardwood chips in a laboratory rocking digester. Kraft pulps of kappa number 16 and 20 mL KMnO4 were produced by pulping under a variety of conditions. The effective alkali (EA) charged to the digester was varied over the range of 12 to 21% while the sodium sulfide content of the pulping liquor was varied between 0 to 30% sulfidity. Cooking temperatures of …
Multiband Analog-To-Digital Conversion, Scott Saucier
Multiband Analog-To-Digital Conversion, Scott Saucier
Electronic Theses and Dissertations
The current trend in the world of digital communications is the design of versatile devices that may operate using several different communication standards in order to increase the number of locations for which a particular device may be used. The signal is quantized early on in the reciever path by Analog-to-Digital Converters (ADCs), which allows the rest of the signal processing to be done by low complexity, low power digital circuits. For this reason, it is advantageous to create an architecture that can quantize different bandwidths at different frequencies to suit several different communication protocols. This thesis outlines the design …
Evaluation Of Dynamic Properties Of A Carbon-Carbon Composite At Elevated Temperatures., Sean Patrick Bunker
Evaluation Of Dynamic Properties Of A Carbon-Carbon Composite At Elevated Temperatures., Sean Patrick Bunker
Electronic Theses and Dissertations
Methods for in-situ monitoring of high temperature composite materials are important in a number of technological applications. In this work a method is developed that makes use of solid cylindrical waveguides to monitor the change of elastic properties and the oxidation reaction of carbon-carbon composites with change in temperature. The apparatus is designed to allow ultrasonic measurements to be performed in a controlled atmosphere at temperatures up to llOO°C. Signal processing required to obtain quantitative information is considered for the experimental apparatus described.
Dynamic Response Of A Mobile Offshore Base Hydroelastic Test Model, Vijay Venkataraman
Dynamic Response Of A Mobile Offshore Base Hydroelastic Test Model, Vijay Venkataraman
Electronic Theses and Dissertations
The objective of the work presented in this thesis deals with the study of dynamic response of a Mobile Offshore Base (MOB) hydroelastic test model. The MOB is a very large floating structure consisting of multiple self-propelled, semi-submersible modules. Physical scale model testing of a notional MOB concept has been conducted and the experimental results have been provided for one, two and four module configurations. This thesis focuses on utilizing the experimental data to understand the dynamic response of the MOB hydroelastic scale module. The analysis of the data is conducted using popular linear and nonlinear data processing techniques. The …
Error Compensation In Pipeline And Converters, Kannan Sockalingam
Error Compensation In Pipeline And Converters, Kannan Sockalingam
Electronic Theses and Dissertations
This thesis provides an improved calibration and compensation scheme for pipeline Analog-to-Digital Converters (ADCs). This new scheme utilizes the intermediate stage outputs in a pipeline to characterize error mechanisms in the architecture. The goal of this compensation scheme is to increase the dynamic range of the ADC. The pipeline architecture is described in general, and tailored to the 1.5 bitslstage topology. Dominant error mechanisms are defined and characterized for an arbitrary stage in the pipeline. These error mechanisms are modeled with basis functions. The traditional calibration scheme is modified and used to iteratively calculate the error characteristics. The information from …
Localization Of Expansin Expression During Adventitious And Lateral Rooting In Response To Auxin In Loblolly Pine, Fuyu Xu
Electronic Theses and Dissertations
Loblolly Pine is the most important and widely cultivated timber species in the southern United States. Due to its fast growth, it is extensively planted for lumber and pulpwood. Vegetative propagation will enhance gains from genetic improvement of tree species. Rooted-cutting is at present the most reliable non-somatic embryogenesis method for cloning specific genotypes. However, an abrupt decline of adventitious rooting capacity has hindered the application of vegetative propagation in loblolly pine. Unraveling the rooting mechanism may facilitate a way to overcome this barrier. Regulation of lateral and adventitious root formation by auxin has been demonstrated through the application of …
Prototype Micro Sensors For The Detection Of Pesticide Residues On Blueberries, Guang Chen
Prototype Micro Sensors For The Detection Of Pesticide Residues On Blueberries, Guang Chen
Electronic Theses and Dissertations
The widespread use of pesticides on commercial food crops can result in short and long term health problems for both f m workers and consumers as well as serious impacts on the environment. Consequently, there is an increasing need to develop low cost portable detection systems that can be used to screen for pesticide residues on food products. Since phosmet (C1 IH12N04PS2) is one of the most commonly used organophosphorous pesticides within the state of Maine, it is selected as the target pesticide to detect in this thesis. Two sensing techniques were investigated. One is the quartz crystal microbalance (QCM), …
Mechanical Testing Of Epoxy Adhesives For Naval Applications, Michael James Boone
Mechanical Testing Of Epoxy Adhesives For Naval Applications, Michael James Boone
Electronic Theses and Dissertations
With advances in composite technology and an understanding of composite application, requirements to develop new design approaches exist. With composite structures today, a basic understanding that both material architecture and joining process, affect the strength of the structure. These design requirements force old techniques of joining, such as bolting and riveting to be re-evaluated. Advantages of adhesives over mechanical means of fastening include higher stiffnesses, more uniform load distribution, parts consolidation, no holes drilled in adherends (with resulting stress concentrations), and, generally, less labor. Adhesives have proven to be a good solution for joining when composites are utilized, but this …
Optimal Recovery Of Elastic Properties For Anisotropic Materials Through Ultrasonic Measurements, Miao Sun
Optimal Recovery Of Elastic Properties For Anisotropic Materials Through Ultrasonic Measurements, Miao Sun
Electronic Theses and Dissertations
Full knowledge of material elastic properties is required to facilitate design in many applications. The existence of misorientation between the geometric axes of the part and the material symmetry axes has in particularly created challenged in design of composite structure. In this thesis the potential for optimal identification of material symmetries for a general anisotropic material through a water immersion technique is explored. The concept is extensible to any class of symmetry groups and does not assume a-priori knowledge of the material. Initial experimental results for determining the elastic constants as well as locating the symmetry planes are presented. Many …
Behavior And Design Of Frp-Reinforced Longitudinal Glulam Deck Bridges, Melanie Marie Bragdon
Behavior And Design Of Frp-Reinforced Longitudinal Glulam Deck Bridges, Melanie Marie Bragdon
Electronic Theses and Dissertations
In 1977, the Weyerhaeuser Company developed a system for short-span timber bridges. The girder-free system consisted of longitudinal, vertically-laminated glulam panels joined by below-deck Transverse Stiffener Beams (TSB). This project addresses two potential areas of improvement in the construction and design of these bridges: a reinforced deck panel and an improved method for TSB design. This project has two objectives: (1) To evaluate the behavior and advantages of longitudinal glulam deck panels reinforced with Fiber-Reinforced Polymers (FRP) and (2) To evaluate existing AASHTO empirical TSB design criteria. The tension-reinforced deck panels can alleviate reliance on high grade wood laminations and …
Development And Structural Testing Of Frp Reinforced Osb Panels For Disaster Resistant Construction, Eric Dana Cassidy
Development And Structural Testing Of Frp Reinforced Osb Panels For Disaster Resistant Construction, Eric Dana Cassidy
Electronic Theses and Dissertations
The resistance of conventionally constructed wood-framed structures to extreme events such as earthquakes and hurricanes depends in large part on the strength and energy absorption characteristics of the shear walls. These shear walls are often sheathed with oriented strand board (OSB) panels, and their performance is primarily a function of the nailed sheathing-to-framing connections at the panel edges. A new sheathing panel called Advanced OSB (AOSB) has been developed at the University of Maine's Advanced Engineered Wood Composites Center. The AOSB panel integrates glass fiberreinforced polymer (GFRP) reinforcing into regions of the OSB panel that have been observed to fail …
Isolation And Characterization Of A Microorganism From Groundwater That Reduces Arsenate, Kevin A. Mccaffery
Isolation And Characterization Of A Microorganism From Groundwater That Reduces Arsenate, Kevin A. Mccaffery
Electronic Theses and Dissertations
This is an investigation into the microbially mediated processes involved in the transformation of arsenic. With the recent change in the Federal Maximum Contaminant Level for arsenic in drinking water, an increasing amount of resources are being devoted to understanding the mechanisms involved in the movement of arsenic. Arsenic in drinking water typically comes from natural sources, but the triggers that result in increased release of arsenic from parent material are poorly understood. Knowledge of these processes is necessary in order to make sound engineering decisions regarding drinking water management practices. Recent years have brought forth the idea that bacteria …
Stress Analysis Of Tapered Sandwich Panels With Isotropic Or Laminated Composite Facings, Huyue Zhao
Stress Analysis Of Tapered Sandwich Panels With Isotropic Or Laminated Composite Facings, Huyue Zhao
Electronic Theses and Dissertations
Structural sandwich construction is used in many air and space vehicles, cargo containers, boats and ships. Connection of the sandwich construction component to a framework or substructure is a critical issue in the detail design for sandwich construction. The tapered connection where the facings are drawn together at the support is one of the most efficient types of connections in composite sandwich construction. We present a tapered sandwich theory that is simple to use, yet accurately predicts the stresses and deflection of both symmetric and non-symmetric tapered sections. In this investigation we assume that the facings are relatively thin and …
High Temperature Compression Testing Of An Advanced Carbon-Carbon Composite In An Oxidizing Atmosphere, Joshua C. Walls
High Temperature Compression Testing Of An Advanced Carbon-Carbon Composite In An Oxidizing Atmosphere, Joshua C. Walls
Electronic Theses and Dissertations
Compression testing of an advanced, three-dimensional weave, carbon-carbon composite was performed from room temperature to 2192°F (1200°C) in an oxidizing environment. The material tested is primarily used for missile nose cones and rocket nozzles. A test system and test method was developed for performing high temperature compression testing and techniques were developed for machining the material to minimize fiber damage and maintain accurate tolerances. Test specimens were cut from a block of the test material in the three principal fiber orientations, and off-axis tests were cut at 45" orientations to each principal fiber direction. The specimens were tested by direct …
Synthesis And Characterization Of Thiol-Grafted Chitosan Beads For Mercury Removal, John D. Merrifield
Synthesis And Characterization Of Thiol-Grafted Chitosan Beads For Mercury Removal, John D. Merrifield
Electronic Theses and Dissertations
This study describes the synthesis and characterization of thiol-grafted chitosan beads for use as mercury (Hg) adsorbents. Chitosan flakes were manipulated into beads using a phase inversion technique, then crosslinked to improve porosity and chemical stability. Cysteine was grafted onto the beads in order to improve the adsorption affinity of Hg to the beads. The beads possessed an average diameter of 3.2 mm, porosity of 0.9, specific surface are of -100 m21g, average pore size of -120 Angstroms, and specific gravity of 2. The beads exhibited a high adsorption capacity for Hg: 2,2.5,3.5 and 8 mmoVg dry at pH values …
Fatigue Life Of Pultruded And Hand Lay-Up Gfrp Exposed To Different Environmental Conditions., Mohammed Asif Iqbal
Fatigue Life Of Pultruded And Hand Lay-Up Gfrp Exposed To Different Environmental Conditions., Mohammed Asif Iqbal
Electronic Theses and Dissertations
The use of unidirectional Glass Fiber Reinforced Polymer (GFRP) composites to reinforce glulam beams in tension has been proven by researchers at University of Maine and others to improve both allowable strength and ductility. The addition of 3% E-glass FRP has been shown to increase the allowable flexural strength by as much as 100%. These promising findings can be used in practice only if the GFRP will maintain a major proportion of its strengthfstiffness mechanical properties over the life of the structure. This study focuses on the fatigue life of two types of E-glasslphenolic GFRP (hand lay-up and pultruded) with …
Los Angeles-Long Beach Harbor Pier 400 Harbor Resonance Study Using Numerical Model, Cgwave, Dongcheng Li
Los Angeles-Long Beach Harbor Pier 400 Harbor Resonance Study Using Numerical Model, Cgwave, Dongcheng Li
Electronic Theses and Dissertations
Ports and harbors can be used for commercial, recreational and military purpose. Compared to other kinds of transportation (railroad, airplane, highways), waterborne commerce has two significant advantages: low cost and high capacity. Many nations use waterborne commerce as a major source of transport. Several major U.S. portsharbors currently have renovation plans in response to the future expansion of ocean-borne world commerce, and coastal engineering projects generally require a detailed knowledge of the wave field in the project areas. Physical and numerical model studies are often conducted concurrently for these projects to evaluate technical feasibility and to optimize design alternatives. A …
Numerical Model Of The Transient Effects Of A Heat Of Fusion Reservoir Interacting With Two-Phase Flow, Anne-Marie Bechard Thibodeau
Numerical Model Of The Transient Effects Of A Heat Of Fusion Reservoir Interacting With Two-Phase Flow, Anne-Marie Bechard Thibodeau
Electronic Theses and Dissertations
The object of this thesis is to develop a numerical model that simulates the transient behavior of a coaxial, thermal energy storage system consisting of a phase changing material ( P O interacting with a two-phase fluid. The purpose of this model would be to have a useful design tool that could be applied when sizing and building iceon- coil, cooling systems (ice-banks). The numerical model is an explicit finite volume approximation applied to the enthalpy method. It solves a two-dimensional, axisymrnetric, heat conduction problem with conjugate forced convection at its inner boundary. Natural convection is neglected in the PCM. …
Repair Of Wood Piles With Fiber Reinforced Composites, Antonis Petrou Michael
Repair Of Wood Piles With Fiber Reinforced Composites, Antonis Petrou Michael
Electronic Theses and Dissertations
Piles made of treated wood have been traditionally used for the construction of piers and other waterfront structures. The main concern related to wood piles is deterioration due to marine borers, which limits the lifespan and requires frequent repair and replacement. Furthermore, since the use of preservative treatments for wood piles has been reduced due to environmental concerns, there is a current need for efficient methods for wood pile protection. Marine borer activity in Maine coastal waters was assessed through a survey directed to harbor masters correlated with historic data. In order to illustrate the type and extent of wood …
Implementation Of An Underwater Digital Acoustic Telemetry Reciever, Raymond A. Mcavoy
Implementation Of An Underwater Digital Acoustic Telemetry Reciever, Raymond A. Mcavoy
Electronic Theses and Dissertations
This thesis presents the design and software implementation of an underwater acoustic modem receiver. Communication links in underwater environments face several undesired effects. These include multipath signal reflections, intersymbol interference, and channel fading. This receiver design uses a combination of time and spatial diversity inputs combined with an adaptive feedback equalizer to counteract those effects. The design is based on three modules. A front-end module demodulates and Doppler-compensates the incoming data. A channel combiner module receives data from one or more front ends for spatial diversity and combines repeated transmissions for time diversity. The data from each input channel is …