Engineering Commons^™

Computational Fluid Dynamics Analysis Of Freeze Drying Process And Equipment, Nikhil P. Varma

Open Access Theses

Freeze drying is an important, but expensive, inefficient and time consuming process in the pharmaceutical, chemical and food processing industries. Computational techniques could be a very effective tool in predictive design and analysis of both freeze drying process and equipment. This work is an attempt at using Computational Fluid Dynamics(CFD) and numerical simulations as a tool for freeze drying process and equipment design.

Pressure control is critical in freeze dryers, keeping in view the product stability. In industrial freeze dryers, loss of pressure control can lead to loss of an entire batch. Pressure variation within the chamber could also lead …

Identifying Conditions To Optimize Lactic Acid Production From Food Waste, Raymond M. Redcorn

Open Access Theses

There is an increased demand for lactic acid for the production of biopolymers and to aid nutrient removal in wastewater treatment. Food waste offers a source of soluble sugars to produce lactic acid, which does not increase land demand, but digestion conditions have yet to be optimized when co-digested with primary sludge. Food waste was collected from cafeteria waste bins, homogenized and seeded with primary sludge. A Box Behnken Response surface design was used to optimize lactic acid production based on pH, temperature, loading rate, and retention time. Subsequent experiments verified and refined those conditions to optimize for both yield …

Impact Of Nanostructure On Polymer-Based Nonvolatile Memory Devices, Seung Hyun Sung

Open Access Theses

Memory functionality is essential for many high-end electronic applications (e.g. , smart phones, personal computers). Particularly, organic nonvolatile memory devices based on polymer ferroelectric materials are a promising approach toward the development of low-cost memory due to the ease of processing and flexibility associated with the device. Here, we will focus on a memory device with a two-component active layer and a diode structure. This ferroelectric diode (FeD) has a nanostructured active layer, composed of ferroelectric and semiconducting polymers, and it can provide easy access to high-performance polymer-based memory devices. In order to create these nanostructured active layers, we …

Correlating Molecular Architecture Of A Radical Polymer Based Copolymer With Its Electrical Transport Properties, Holly Chan

Open Access Theses

The design and synthesis of electrically-conductive macromolecules can lead to significant improvements in the performance of polymer-based energy conversion devices (e.g., thermoelectric devices). For these organic electronic devices, conjugated polymers have dominated the area of conductive polymers; however, these materials are usually synthesized using conditions that lead to poorly-defined polymers. Furthermore, in these increasingly-standard polymers, the charge transport ability of the polymer thin films is largely affected by the degree of crystallinity, which is a difficult property to control in a reproducible fashion. Therefore, we seek to explore a new class of amorphous, non-conjugated polymers containing a stable radical …

Identifying, Monitoring, Quantifying And Converting Algae To Bio-Fuels In Bio-Reactors, Alice C. Jernigan

Graduate Theses and Dissertations

Growing algae as a source for bio-fuels has become an area of interest due to concerns about global warming and the reliability and ecology of the production of fossil fuels. Dried algae harvested from a pilot water quality improvement technology at the Rockaway Wastewater Treatment Facility in New York were examined as a source of carbohydrates and lipids for the production of bio-fuels in bio-reactors. The length of storage time, storage conditions, sugar and lipid extraction processes, and fuel production were studied. The results show that if the algae is stored dry (0.015 g/g algae even after a year in …

Mechanistic Study Of The Hydrothermal Reduction Of Palladium On The Tobacco Mosaic Virus, Oluwamayowa Oluwarotimi Adigun

Open Access Theses

Synthesis of nanorods and nanowires is becoming more and more important due to interest in them in a wide range of disciplines. The genetically engineered tobacco mosaic virus (TMV1Cys) provides a template for synthesis of uniform metal nanorods at mild operating conditions and without the use of any expensive technology compared to conventional synthetic methods. The discovery of the hydrothermal synthetic scheme has allowed the production of higher quality nanorods on the TMV template. However, the mechanism for reduction and growth in this process is still not understood. In this paper, the mechanism of synthesis for producing uniform, controllable palladium …

Cztsse Thin Film Solar Cells : Surface Treatments, Chinmay S. Joglekar

Open Access Theses

Chalcopyrite semiconducting materials, specifically CZTS, are a promising alternative to traditional silicon solar cell technology. Because of the high absorption coefficient; films of the order of 1 micrometer thickness are sufficient for the fabrication of solar cells. Liquid based synthesis methods are advantageous because they are easily scalable using the roll to roll manufacturing techniques.

Various treatments are explored in this study to enhance the performance of the selenized CZTS film based solar cells. Thiourea can be used as a sulfur source and can be used to tune band gap of CZTSSe. Bromine etching can be used to manipulate the …

Lab-Scale Fast-Hydropyrolysis And Vapor-Phase Catalytic Hydrodeoxygenation For Producing Liquid Fuel Range Hydrocarbons From Intact Biomass, Vinod Kumar Venkatakrishnan

Open Access Dissertations

Liquid transportation fuels are primarily produced from petroleum-based non-renewable carbon sources. Sustainably available lignocellulosic biomass, as a renewable form of atmospheric carbon, could be utilized to produce hydrocarbon-based fuels with high energy density. One of the process options for this conversion is the H2Bioil process, where biomass is rapidly heated in a hydrogen environment to produce fast-hydropyrolysis vapors that are catalytically upgraded in downstream hydrodeoxygenation (HDO) to produce hydrocarbons. This process has been modeled to have high carbon and energy efficiencies of ~70% and ~75%, respectively.

This dissertation presents the results of a lab-scale experimental proof-of-concept for the H2Bioil process …

Multiscale Modeling Study Of Methanol Oxidation By Ion-Modified Mdh Enzymes, Purnima Kharidehal

Doctoral Dissertations

Enzymes have been considered as molecular electrocatalysts due to their extraordinary characteristics such as their ability to accelerate reactions enormously, to operate under physiological conditions, and to produce fewer by-products during a catalytic reaction. However, enzyme based fuel cells have been reported to have power output and stability limitations, which are restricting the use of this kind of fuel cell to small electronic devices. Methanol dehydrogenase (MDH) is one such enzyme, which oxidizes methanol and other primary alcohols to their corresponding aldehydes. The active site of MDH contains a divalent cation (Ca2+), a co-factor pyrrolo-quinoline quinone (PQQ), several amino acids, …