Engineering Commons^™

Advances In Cellulose Nanomaterial-Based Foams For Environmental Applications, Md Musfiqur Rahman

Electronic Theses and Dissertations

The use of metal-oxide nanoparticles adsorbents is limited to fixed-bed columns in industrial-scale water treatment applications. This limitation is commonly attributed to the tendency of nanoparticles to aggregate, the use of non-sustainable and inefficient polymeric resins as supporting materials, or a lack of adsorption capacity. Foams and aerogels derived from cellulose nanomaterials have unique characteristics, such as high porosity and low density, which enables their use in a variety of environmental applications, including water treatment. However, the overall use of cellulose nanomaterial-based foams in various environmental sectors is limited due to the high cost of production associated with time- and …

The Development Of An Advanced Biorefinery To Produce Cellulosic Sugars And Bionanomaterials, Carlaile Fernanda De Oliveira Nogueira

Electronic Theses and Dissertations

Market trends show growing interest in cellulose nanomaterials due to their low environmental impact. However, current nanocellulose isolation technologies face technoeconomic and life cycle limitations. Previous research has shown that enzymatic treatments effectively reduce the energy input for mechanical nanocellulose isolation. Simultaneously, there is potential to improve the viability of cellulosic ethanol facilities by coproducing nanocelluloses as high-value product obtained from agricultural feedstock. Here, our goal was to study the mass balance of enzymatic-mechanical processes that coproduces cellulosic sugars and nanocelluloses, evaluating the technical feasibility of converting lignified and non-lignified materials.

First, we have determined a feasible 50:50 mass ratio …

Estimation Of Wood Pulp Fiber Species Composition From Microscopy Images Using Computer Vision, Tyler Seekins

Electronic Theses and Dissertations

Pulp mills and papermakers require careful control of input raw materials. The paper pulp composition, consisting of blends of different wood fiber types, affects multiple final product properties in interacting ways and impacts process operating conditions. Manual estimation of composition by classification and counting using microscopy is time consuming, repetitive, error-prone, and fibers are not always identifiable. Using a dataset of 359,840 fibers from 12,690 images of either hardwood or softwood fibers from 423 microscopy slides with data partitioned into 60% training, 20% validation, and 20% testing splits by slide, and a sequence of principal components analysis, Gaussian mixture, image …

Measuring Of Thermal Conductivity And Heat Capacity Of Different Papers And Heat-Sealing Process Of Papers With A Polymer Layer, Amenah Khalaf

Electronic Theses and Dissertations

Packaging is an important and safe way to protect our food and other things through transportation, but the use of plastic based packaging is causing issues with plastic pollution. To replace plastic packaging with a paper-based option that has a barrier coating, good heat sealing will be needed to be a drop-in replacement. While much as been studied on the heat sealing of polymer layers, little has been reported around the heat sealing of paper that has a polymeric barrier coating.

Experiments were conducted to characterize the thermal conductivity and heat capacity of paper as a function of press pressure …

Use Of Photo Isomers To Enhance The Removal Of Lignin From Woody Biomass Hydrolysate, Dipesh J. Karki

Electronic Theses and Dissertations

In this investigation we propose a novel method to enable precipitation of desired solutes using photo-isomers in the extraction solvent. This photo-switchable solvent would enable dissolution or precipitation of desired components using alternating UV or visible light to modify the solubility of the compounds of interest. Three photo-isomers namely native azobenzene, diethoxy azobenzene and diethylamino azobenzene were studied in three different organic solvents: medium chain length alcohol, ethanol and acetone. It was found that among the different combinations of solvent and photo-isomer, acetone and the 4,4’-diethoxy azobenzene solution was most efficient at precipitating dissolved lignin in response to UV light …

Efficient Sintering Of Lunar Soil Using Concentrated Sunlight, Diprajit Biswas

Electronic Theses and Dissertations

Construction material is one crucial need for long-term habitation on the moon. When concentrated for high heat flux, solar radiation can heat lunar soil or regolith until it sinters at temperatures above 900°C. The solid, sintered soil simulant can be used as construction material. This work explores the conditions leading to effective lunar soil sintering for both direct and indirect irradiated sintering. Lunar soil simulants were sintered using concentrated light from a xenon-arc lamp with varying heat flux intensity. During direct sintering of LHS-1, a sintering range of 860°C-1140°C corresponding to a peak heat flux of 105-120 kW/m2 was identified …

The Influence Of Pre Coating Layers On Barrier Coatings, Kritee Pokharel

Electronic Theses and Dissertations

Layers of cellulose nanofibrils (CNF) on paper have been demonstrated to be an effective barrier against oxygen and grease and have been shown to improve the barrier performance of dispersion-based barrier coatings. The potential to produce paper grades that have good oxygen, grease, and moisture barrier properties is clear, but a good understanding of the synergies between CNF, other coating layers, and water-borne barrier coatings (WBBC) is not clear. Different coat weights of a WBBC were applied to papers that have a range of different qualities and amounts of the CNF layer on them. The same WBBC was also applied …

Solid Acid Catalyzed Dehydration Reactions Of Biomass-Derived Alcohols, Mackenzie Todd

Electronic Theses and Dissertations

Concerns around climate change and the use of fossil resources contributing to increasing carbon dioxide concentrations in the atmosphere has motivated transitions to use biomass resources for the production of specialty chemicals and fuels, in hopes of creating a more cyclical use of carbon. The work presented here focuses on two different aspects of catalytic upgrading of biomass-derived platform molecules using heterogeneous acid catalysts. First, we use an interdisciplinary and iterative approach to process development for producing a diesel fuel additive from pyrolysis oils of woody biomass. We use fuel property calculations to define measures of success in chemical upgrading …

The Influence Of Heat And Mass Transfer On The Setting Rate Of Adhesives Between Porous Substrates, Mubarak Mohammed Khlewee

Electronic Theses and Dissertations

The dynamic penetration of fluid into a porous media where other changes are occurring such as temperature or concentration is of interest to a number of situations. However, little experimental and theoretical analysis of this situation is found in the literature where most of the previously published works have studied the penetration with constant physical properties, where there is no change of the fluid as it enters the pores. This situation is important in the setting of adhesives in porous medium such as in the setting of hot melt and water-based adhesives in the production of paper based packaging. The …

Investigation Of Pulsed Electrolysis For Hypochlorous Acid Production, Khoa V. Kieu

Electronic Theses and Dissertations

Because of the Covid-19 pandemic along with the delay in the worldwide supply chain, there were disinfectant shortages that lasted for weeks around the world. Therefore, on-site production is a promising solution to satisfy the increasing demand. As more and more people are shifting toward safer and more environmentally friendly products, we are interested in investigating the electrolysis of sodium chloride (NaCl) solution to produce hypochlorous acid (HOCl). Electrolysis is inexpensive as it requires only sodium chloride and electricity, and it does not have any negative impact on the environment. Moreover, electrolysis can be coupled with renewable energy to utilize …

Disinfection Applications Of On-Site Hypochlorous Acid Production, Deborah Ngabanyi Sebagisha

Electronic Theses and Dissertations

Hypochlorous acid (HOCl) is a weak acid, but strong oxidizing agent produced naturally in the human body to fight viruses and bacteria. Hypochlorous acid can be produced by electrolysis of sodium chloride and water enabling local production of disinfectant, where it is needed. Hypochlorous acid has many applications including in wound care, skin care, and disinfection of health and dental clinics. In this work, two hypochlorous acid applications were explored that could utilize local production by electrolysis. These applications were wastewater treatment and sanitization of dental operating rooms.

An electrochemical reactor and process were designed, constructed, and tested for hypochlorous …

S8e10: How Can Nature-Inspired Engineering Improve Human Health?, Ron Lisnet, Caitlin Howell

The Maine Question

Antibiotic resistance has become a growing problem in the treatment of bacterial infections. In addition to minimizing or negating the effects of existing medicine, these antibiotic-resistant bacteria, or “superbugs,” are mutating faster than the development of new remedies.

Caitlin Howell, University of Maine associate professor of biomedical engineering, is working on new tools that take notes from nature to combat antibiotic-resistant bacteria. Similar to the way in which the human body keeps balance with its own bacterial populations, Howell’s devices use nontoxic, non-invasive surface-based technology to trap bacteria and prevent them from spreading.

In this episode of “The Maine Question” …