Chemical Engineering Commons^™

Conformationally Superarmed S-Ethyl Glycosyl Donors As Effective Building Blocks For Chemoselective Oligosaccharide Synthesis In One Pot, Mithila Bandara, Jagodige Yasomanee, Nigam Rath, Christian Pedersen, Mikael Bols, Alexei Demchenko

Chemistry & Biochemistry Faculty Works

A new series of superarmed glycosyl donors has been investigated. It was demonstrated that the S-ethyl leaving group allows for high reactivity, which is much higher than that of equally equipped S-phenyl glycosyl donors that were previously investigated by our groups. The superarmed S-ethyl glycosyl donors equipped with a 2-O-benzoyl group gave complete β-stereoselectivity. Utility of the new glycosyl donors has been demonstrated in a one-pot one-addition oligosaccharide synthesis with all of the reaction components present from the beginning.

Determination Of Aqueous Surfactant Solution Surface Tensions With A Surface Tensiometer, Remelisa Esteves, Birce Dikici Ph.D, Matthew Lehman, Qayyum Mazumder, Nonso Onukwuba

Beyond: Undergraduate Research Journal

Surfactant solutions are applicable to engineering systems for cooling equipment for electronics. Surfactants can be added to water to improve heat transfer. An application of using aqueous surfactant solutions can be through microchannel heat sink. Although it is ideal to redesign these systems to reduce heat, it is a costly method. Surfactant solutions at optimal solution concentration can be able to transfer heat quickly and effectively with minimum expense. The surface tension of surfactant solutions is an important parameter for boiling heat transfer and must be taken into consideration. The purpose of this research is to measure surface tension of …

Determination Of Surfactant Solution Viscosities With A Rotational Viscometer, Remelisa Esteves, Nonso Onukwuba, Birce Dikici Ph.D

Beyond: Undergraduate Research Journal

Aqueous surfactant solutions are used in engineering systems for improving boiling heat transfer. The purpose of this research is to determine the viscosities of surfactant solutions and to investigate the effect of composition on viscosity. The results obtained can possibly be used as reference for further study in the effects of surfactant solution viscosities on nucleate boiling. A rotational viscometer was used to determine the viscosities of three surfactant solutions – SLS, EH-14, and SA-9 – of various compositions at room temperature. It was discovered that the viscosities of SLS, EH-14, and SA-9 had a nearly consistent pattern as their …

Development Of Metal Matrix Composite Gridlines For Space Photovoltaics, Omar K. Abudayyeh

Chemical and Biological Engineering ETDs

Space vehicles today are primarily powered by multi-junction photovoltaic cells due to their high efficiency and high radiation hardness in the space environment. While multi-junction solar cells provide high efficiency, microcracks develop in the crystalline semiconductor due to a variety of reasons, including: growth defects, film stress due to lattice constant mismatch, and external mechanical stresses introduced during shipping, installation, and operation. These microcracks have the tendency to propagate through the different layers of the semiconductor reaching the metal gridlines of the cell, resulting in electrically isolated areas from the busbar region, ultimately lowering the power output of the cell …

Photocatalytic Reduction Of Co2 With Tunable Bandgap And Bandedge Materials, Thuhuong T. Ngo

USF Tampa Graduate Theses and Dissertations

Solar energy is a sustainable resource which has substantial potential to meet the increasing demand for renewable energy. Though there has been some success in harvesting solar energy for electricity production, converting solar energy to chemical energy as fuels is still a challenge due to low efficiency.

Since the discovery of TiO₂ photocatalysts for splitting water (4) and reducing CO₂ (5) to form useful chemical feedstock such as H₂, CO and CH₄, much research has been done to increase the efficiency of photocatalysts. However, the current conversion efficiency of photocatalysts remains low (~5%) (6, …

Fabrication Of High Performing Pemfc Catalyst-Coated Membranes With A Low Cost Air-Assisted Cylindrical Liquid Jets Spraying System, Xiong Peng, Travis Omasta, William Rigdon, William E. Mustain

Faculty Publications

In this work, a low cost air-assisted cylindrical liquid jets spraying (ACLJS) system was developed to prepare high-performance catalyst-coated membranes (CCMs) for proton exchange membrane fuel cells (PEMFCs). The catalyst ink was flowed from a cylindrical orifice and was atomized by an air stream fed from a coaxial slit and sprayed directly onto the membrane, which was suctioned to a heated aluminum vacuum plate. The CCM pore architecture including size, distribution and volume can be controlled using various flow parameters, and the impact of spraying conditions on electrode structure and PEMFC performance was investigated. CCMs fabricated in the fiber-type break-up …

Electrochemical Fabrication Of Energetic Thin Films, Jonathan J. Coleman

Chemical and Biological Engineering ETDs

Current thermal battery heat sources suffer from slow reaction propagation rates and require extreme care when handling to protect from inadvertent ignition sources. Nanostructured intermetallic heat sources are strong candidates for improved heat sources as they have high enthalpy of reaction, are highly conductive before and after firing and are completely gasless reactions. Current fabrication methods of these heat sources rely on a PVD multistep layering process that is time and capital intensive, and cost prohibiting to their use. The composition and nanostructuring these films require can be provided with electrochemical codeposition, where the two components (aluminum and nickel) are …

Dielectric Characterization Of Mylar And The Effects Of Doping Processes, Cami B. Belcher

Chemical and Biological Engineering ETDs

Mylar® polymer is a bi-axially oriented polyethylene terephthalate (PET) polymer film used widely as a dielectric, specifically in capacitors. The dielectric characteristics of Mylar have been well studied and documented over the years; however, many of the mechanisms responsible for dielectric breakdown and failure are not understood for modified versions of the material. Previous studies on Mylar confirm that factors such as temperature, humidity, and voltage ramp rates can also have a significant effect on the dielectric properties and measurement of the dielectric properties. This study seeks to determine how dielectric properties, including permittivity, dielectric loss, and breakdown strength, are …

Peridynamic Modeling Of Ruptures In Biomembranes, Michael Taylor, Irep Gözen, Samir Patel, Aldo Jesorka, Katia Bertoldi

Mechanical Engineering

We simulate the formation of spontaneous ruptures in supported phospholipid double bilayer membranes, using peridynamic modeling. Experiments performed on spreading double bilayers typically show two distinct kinds of ruptures, floral and fractal, which form spontaneously in the distal (upper) bilayer at late stages of double bilayer formation on high energy substrates. It is, however, currently unresolved which factors govern the occurrence of either rupture type. Variations in the distance between the two bilayers, and the occurrence of interconnections (“pinning sites”) are suspected of contributing to the process. Our new simulations indicate that the pinned regions which form, presumably due to …

Evaluation Of Ultrasound Assisted Potassium Permanganate Pre-Treatment Of Spent Coffee Waste, Rajeev Ravindran, Swarna Jaiswal, Nissreen Abu-Ghannam, Amit Jaiswal

Articles

In the present study, novel pre-treatment for spent coffee waste (SCW) has been proposed which utilises the superior oxidising capacity of alkaline KMnO₄ assisted by ultra-sonication. The pre-treatment was conducted for different exposure times (10, 20, 30 and 40 min) using different concentrations of KMnO₄ (1,2, 3, 4, 5% w/v) at room temperature with solid/liquid ratio of 1:10. Pretreating SCW with 4% KMnO₄ and exposing it to ultrasound for 20 min resulted in 98% cellulose recovery and a maximum lignin removal of 46%. 1.7fold increase in reducing sugar yield was obtained after enzymatic hydrolysis of KMnO_{4 …}

Inhibition Of Microbial Biofuel Production In Drought-Stressed Switchgrass Hydrolysate, Rebecca Garlock Ong, Alan Higbee, Scott Bottoms, Quinn Dickinson, Dan Xie, Scott A. Smith, Jose Serate, Edward Pohlman, Arthur Daniel Jones, Joshua J. Coon, Trey S. Kato, Gregg R. Sanford, Dustin Eilert, Dustin G. Oates, Jeff S. Piotrowski, Donn M. Bates, David Cavalier, Yaoping Zhang

Department of Chemical Engineering Publications

Background:

Interannual variability in precipitation, particularly drought, can affect lignocellulosic crop biomass yields and composition, and is expected to increase biofuel yield variability. However, the effect of precipitation on downstream fermentation processes has never been directly characterized. In order to investigate the impact of inter-annual climate variability on biofuel production, corn stover and switchgrass were collected during 3 years with significantly different precipitation profiles, representing a major drought year (2012) and 2 years with average precipitation for the entire season (2010 and 2013). All feedstocks were AFEX (ammonia fiber expansion)-pretreated, enzymatically hydrolyzed, and the hydrolysates separately fermented using xylose-utilizing strains …

Mechanistic Investigation Toward A Microkinetic Model For Decarboxylation Of Gamma Valerolactone Over Silica Alumina, Christian Suhngwa Jungong

Theses - ALL

γ-valerolactone (GVL) ring opening- and decarboxylation rates were measured over amorphous silica alumina (SiO2/Al2O3) catalyst in the gas phase, using a down configuration fixed bed reactor, operating under anhydrous and differential conditions. By varying temperature, space time and GVL partial pressure, measured rates were leveraged to determine kinetic parameters (apparent activation barriers and pre-exponential factors) for the ring opening and decarboxylation step, as well as thermodynamic parameters (enthalpy- and entropy of reaction) for the ring opening step. The experimentally measured parameters were applied for the development of a microkinetic model that quantitatively describes the overall kinetics involved in the decarboxylation …

Mechanistic Investigation Toward A Microkinetic Model For Decarboxylation Of Gamma Valerolactone Over Silica Alumina, Christian Suhngwa Jungong

Theses - ALL

γ-valerolactone (GVL) ring opening- and decarboxylation rates were measured over amorphous silica alumina (SiO2/Al2O3) catalyst in the gas phase, using a down configuration fixed bed reactor, operating under anhydrous and differential conditions. By varying temperature, space time and GVL partial pressure, measured rates were leveraged to determine kinetic parameters (apparent activation barriers and pre-exponential factors) for the ring opening and decarboxylation step, as well as thermodynamic parameters (enthalpy- and entropy of reaction) for the ring opening step. The experimentally measured parameters were applied for the development of a microkinetic model that quantitatively describes the overall kinetics involved in the decarboxylation …

Evaluation Of Stochastic Particle Dispersion Modeling In Turbulent Round Jets, Guangyuan Sun, John C. Hewson, David O. Lignell

Faculty Publications

ODT (one-dimensional turbulence) simulations of particle-carrier gas interactions are performed in the jet flow configuration. Particles with different diameters are injected onto the centerline of a turbulent air jet. The particles are passive and do not impact the fluid phase. Their radial dispersion and axial velocities are obtained as functions of axial position. The time and length scales of the jet are varied through control of the jet exit velocity and nozzle diameter. Dispersion data at long times of flight for the nozzle diameter (7 mm), particle diameters (60 and 90 µm), and Reynolds numbers (10, 000–30, 000) are …

Biomarker Detection At Risk Forecasting Level Using Metal-Enhanced Fluorescence Combined With Surface Acoustic Wave, Jun Liu

USF Tampa Graduate Theses and Dissertations

In this paper, metal-enhanced fluorescence (MEF) technique is used to lower the detection limit of carcinoembryonic antigen (CEA) which is able to be utilized in forecasting the risk of having certain kinds of cancers, especially colon and rectal cancer. By incubating silver nanocubes (Ag NCs) on the surface of the chips, the detection limit goes down to below 1ng/mL of CEA. Also, when combining MEF with surface acoustic wave (SAW) devices, the incubation time between antigen and antibody will decrease significantly with the fluorescence signal keeping similar or higher level.

Preparation Of Nano-Size Ceramic Membrane From Industrial Waste, Shereen K. Amin, Mai H. Roushdy, Chakinaz Aly El-Sherbiny, Heba Mohamed Abdallah, Magdi F. Abadir

Chemical Engineering

Industrial ceramic wastes are becoming an increasing problem worldwide. Recently, this problem has attracted social concern due to the growing amounts of waste despite the measures and precautions that have been taken worldwide aiming at managing such wastes. One promising solution that has been recently researched consists incorporating such wastes in ceramic bodies which besides minimizing the waste load often improve the quality of the ceramic body. Roller kilns used in the production of ceramic tiles are routinely ground to remove traces of contamination. The fine ground powder is usually discarded as a useless waste. In the present paper, the …

Experimental Investigation Of Co2 Transport Through Combined Membrane Absorber And Regenerator, Nima Mohammadrasool Atbaei

Chemical and Petroleum Engineering Theses

Greenhouse gases such as carbon dioxide have been known to contribute significantly to global warming, which in turn has resulted in serious global environmental problems. Carbon dioxide is the main gaseous contaminant in the atmosphere, representing about 80% of greenhouse gases. It is reported that industry and power plants using fossil fuels such as coal-combustion power generators produce half of the CO₂ emissions. These emissions create the need for low energy-consumption, and efficient technologies for the capture and removal of CO₂ from gas mixtures produced by industrial sources.

Conventional gas absorption processes for the removal of CO_{2 …}

The Study Of Dynamical Electrochemical Impedance Spectroscopy For Oxygen Reduction Reaction On Pt/C Catalyst, Kun-Ming Shi, Jian-Wei Guo, Jia Wang

Journal of Electrochemistry

With joint techniques of rotating disc electrode(RDE) and electrochemical impedance spectroscopy(EIS), and further establishment on equivalent circuit model, this paper studied oxygen reduction reaction(ORR) on commercial Pt/C catalyst in acid medium. Our results found that the dynamical interface on Pt/C consists of two independent processes: 1) the PtO reduction from Pt surface, 2) the new PtO formation from ORR, thus providing key clues for catalyst stability and activity. This also implied that the dynamical interface facilitates reconstruction for porous electrode, and matches with mass transfer. One important issue is discovered that at high overpotential, the high reaction rate for ORR …

Continuous Synthesis And Condition Exploration Of Precursor Ni1/3Co1/3Mn1/3(Oh)2 Ternary Cathode Material, Zhi-Jun Jiang, Ya-Li Zhang, Qian Wang, Hui Zhang

Journal of Electrochemistry

Commercial LiNi_1/3Co_1/3Mn_1/3(OH)₂ ternary material is generally prepared by a combination of co-precipitation and solid state reaction method. The particle size distribution and morphology of Ni_1/3Co_1/3Mn_1/3(OH)₂ precursor have a great impact on the electrochemical performance of LiNi_1/3Co_1/3Mn_1/3O₂. In this work, the precursor Ni_1/3Co_1/3Mn_1/3(OH)₂ ternary cathode material was prepared by co-precipitation method with MnSO₄, NiSO₄, and CoSO₄ as raw materials, NaOH as a precipitating agent and NH_{3 …}

Template-Assisted Hydrothermal Synthesis Of Nio@Co3O4 Hollow Spheres With Hierarchical Porous Surfaces For Supercapacitor Applications, Wen Zhou, Xue-Feng Lu, Ming-Mei Wu, Gao-Ren Li

Journal of Electrochemistry

Hollow structures have shown great potentials in a variety of important applications, such as energy conversion and storage. In order to further enhance the performance, the rational design of hollow structures with higher complexity in terms of composition and structure is highly desirable and still remains a great challenge. In this work, an efficient strategy was established for the fabrication of novel NiO@Co₃O₄ hollow spheres (HSs) with hierarchical porous surfaces by silica spheres template-assisted hydrothermal synthesis. The as-fabricated NiO@Co₃O₄ HSs showed high specific surface area of 219.68 m²·g^-1, and significant …