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Full-Text Articles in Engineering

Investigation Of Oxygen Reduction Reaction In Carbon-Based Electrocatalysts, Andrew Mason Oct 2019

Investigation Of Oxygen Reduction Reaction In Carbon-Based Electrocatalysts, Andrew Mason

Honors Theses, University of Nebraska-Lincoln

In the modern era, some global challenges are energy storage conversion. To find sustainable solutions to this problem, researchers have turned to renewable energy resources. An example of promising energy generation devices is fuel cell. Fuel cells are electrochemical systems that convert the chemical energy of the fuel to electrochemical potential that can be used as direct current (dc) generators. Although these technologies are very attractive, they are known to be expensive due to high cost of catalysts and concerns regarding their energy densities. Fuel cells composed of two electrodes, namely cathode and anode and electrolyte separating the oxidizing agents ...


Fabrication Of Polyvinylidene Fluoride Hollow Fiber Membranes For Membrane Distillation, Abdullah Al Balushi Aug 2019

Fabrication Of Polyvinylidene Fluoride Hollow Fiber Membranes For Membrane Distillation, Abdullah Al Balushi

Chemical & Biomolecular Engineering Theses, Dissertations, & Student Research

Desalination technologies can help humanity tap into the most abundant source of water on earth, seawater; however, desalination is an energy-demanding process. Most of the desalination plants worldwide use conventional energy resources; therefore, desalination leaves a large carbon footprint. Solar energy is an available source of energy that can be harvested and integrated into desalination systems.

Membrane distillation (MD) is an emerging purification technology that many offers many advantages over traditional desalination systems. For starters, it can utilize low-grade thermal energy to drive the separation, therefore, it can be suitably integrated into the solar-thermal energy scheme. Additionally, MD can be ...


Modeling The Interplay Between Photosynthesis, Co2 Fixation, And The Quinone Pool In A Purple Non-Sulfur Bacterium, Adil Alsiyabi Jul 2019

Modeling The Interplay Between Photosynthesis, Co2 Fixation, And The Quinone Pool In A Purple Non-Sulfur Bacterium, Adil Alsiyabi

Chemical & Biomolecular Engineering Theses, Dissertations, & Student Research

Rhodopseudomonas palustris CGA009 is a purple non-sulfur bacterium (PNSB) that can fix CO2 and nitrogen or break down organic compounds for its carbon and nitrogen requirements. Light, inorganic, and organic compounds can all be used for its source of energy. Excess electrons produced during its metabolic processes can be exploited to produce hydrogen gas or biodegradable polyesters (polyhydroxybutyrate). A genome-scale metabolic model of the bacterium was reconstructed to study the interactions between photosynthesis, carbon dioxide fixation, and the redox state of the quinone pool. A comparison of model-predicted flux values with published in vivo MFA fluxes resulted in predicted ...


Fibrinogen, Factor Xiii And Fibronectin: A Biophysical And Kinetic Characterization Of Their Interactions, Frank Fabian Jun 2019

Fibrinogen, Factor Xiii And Fibronectin: A Biophysical And Kinetic Characterization Of Their Interactions, Frank Fabian

Chemical & Biomolecular Engineering Theses, Dissertations, & Student Research

The development of recombinant-based liquid fibrin tissue sealants having enhanced hemostatic and wound healing properties will involve understanding as yet not well characterized interactions between fibrinogen, fibrin (Fbn) factor XIII, thrombin and fibronectin. We study these phenomena in the context of comparing plasma derived fibrinogen to recombinant fibrinogen (rFI) produced in the milk of transgenic cows. An abundance of purified γγ and γγ’ FI subspecies enables detailed study of γγ or γγ’ biomonomer and their respective Fbn biopolymer formation as having different substrate behaviors of activated plasma derived factor XIII (pFXIIIa2b2). High pressure size exclusion (HPSEC) and ...


Biomethane Production From Distillery Wastewater, Zachary Christman Jun 2019

Biomethane Production From Distillery Wastewater, Zachary Christman

Theses, Dissertations, and Student Research in Agronomy and Horticulture

Distillery wastewater treatment is a great ecological problem, for example, India produces 2.7 billion liters of alcohol that results in 40 billion liters of wastewater. However, this material can be seen as a resource since 11 million cubic meters of biogas at 60% methane could be produced in addition to cleaning the water. The distillery has two options of what to do with the biogas. The first is to use the biogas to fuel the distillery making the production plant more energy efficient and removing some of the need to buy natural gas. The other is to upgrade the ...


Improving The Distribution And Use Of Biogas By Conversion To Methanol, Zachary Christman Mar 2019

Improving The Distribution And Use Of Biogas By Conversion To Methanol, Zachary Christman

Theses, Dissertations, and Student Research in Agronomy and Horticulture

In this technology review, the process of turning an average biogas into methanol will be presented. The purpose is to find a better method of transporting the energy contained within biogas so that it may be used in industry as a value added product. The first step is removal of hydrogen sulfide, a corrosive chemical that can breakdown mechanical parts. The second step is carbon capture and conversion of the biogas into hydrogen. The final step is the hydrogenation of carbon dioxide into methanol using a copper catalyst and an alcohol co-catalyst.


Comparative Kinetic Modeling Of Growth And Molecular Hydrogen Overproduction By Engineered Strains Of Thermotoga Maritima , Raghuveer Singh, Rahul Tevatia, Derrick White, Yasar Demirel, Paul H. Blum Jan 2019

Comparative Kinetic Modeling Of Growth And Molecular Hydrogen Overproduction By Engineered Strains Of Thermotoga Maritima , Raghuveer Singh, Rahul Tevatia, Derrick White, Yasar Demirel, Paul H. Blum

Chemical and Biomolecular Engineering -- All Faculty Papers

Thermotoga maritima is an anaerobic hyperthermophilic bacterium known for its high amounts of hydrogen (H2) production. In the current study, the kinetic modeling was applied on the engineered strains of T. maritima that surpassed the natural H2 production limit. The study generated a kinetic model explaining H2 overproduction and predicted a continuous fermentation system. A Leudking-Piret equation-based model predicted that H2 production by Tma200 (0.217 mol-H2 g–1-biomass) and Tma100 (0.147 mol-H2 g–1-biomass) were higher than wild type (0.096 mol-H2 g–1 -biomass) with reduced rates of ...


Extraction Of Astaxanthin From Engineered Camelina Sativa Seed Using Ethanol-Modified Supercritical Carbon Dioxide, Liyang Xie, Edgar B. Cahoon, Yue Zhang, Ozan Ciftci Jan 2019

Extraction Of Astaxanthin From Engineered Camelina Sativa Seed Using Ethanol-Modified Supercritical Carbon Dioxide, Liyang Xie, Edgar B. Cahoon, Yue Zhang, Ozan Ciftci

Faculty Publications in Food Science and Technology

Natural astaxanthin, a high-value carotenoid that is currently extracted mainly from marine organisms, was extracted from engineered camelina seed using ethanol-modified supercritical carbon dioxide (SC-CO2) for the first time, and compared with hexane and accelerated solvent extraction using hexane and ethanol. Response surface methodology (RSM) based on central composite rotatable design was employed to investigate the effect of pressure (30–45 MPa), temperature (40–60 °C), and ethanol concentration (10–35%, w/w). RSM-optimized conditions (41.6 MPa, 36.6 °C and 42.0% ethanol concentration) predicted the astaxanthin concentration as 437 μg/g oil, whereas the actual concentration ...