Materials Science and Engineering Commons^™

Low Molecular Weight Glucosamine/L-Lactide Copolymers As Potential Carriers For The Development Of A Sustained Rifampicin Release System: Mycobacterium Smegmatis As A Tuberculosis Model, Jorge Ragusa

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Tuberculosis, a highly contagious disease, ranks as the second leading cause of death from an infectious disease, and remains a major global health problem. In 2013, 9 million new cases were diagnosed and 1.5 million people died worldwide from tuberculosis. This dissertation aims at developing a new, ultrafine particle-based efficient antibiotic delivery system for the treatment of tuberculosis. The carrier material to make the rifampicin (RIF)-loaded particles is a low molecular weight star-shaped polymer produced from glucosamine (molecular core building unit) and L-lactide (GluN-LLA). Stable particles with a very high 50% drug loading capacity were made via electrohydrodynamic atomization. Prolonged …

Microstructure And Magnetic Behavior Studies Of Processing-Controlled And Composition-Modified Fe–Ni And Mn–Al Alloys, Yunlong Geng

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

L1₀-type (Space group P4/mmm) magnetic compounds, including FeNi and MnAl, possess promising technical magnetic properties of both high magnetization and large magnetocrystalline anisotropy energy, and thus offer potential in replacing rare earth permanent magnets in some applications.

In equiatomic Fe-Ni, the disorder-order transformation from fcc structure to the L1₀ structure is a diffusional transformation, but is inhibited by the low ordering temperature. The transformation could be enhanced through the creation of vacancies. Thus, mechanical alloying was employed to generate more open-volume defects. A decrease in grain size and concomitant increase in grain boundary area resulted from …

The Development Of A Laminated Copolyester Electric Guitar, Addison S. Karnes

Electronic Theses and Dissertations

This thesis is an investigation of the fabrication and assembly methodologies employed in the development of a proof-of-principle prototype electric guitar composed of laminated copolyester. The objective of the project was to develop the processes and procedures to create an optimized physical and visual bond between layers to minimize vibratory dissipation, thus maximizing sustain. A high speed CNC router, abrasive waterjet, laser engraver-cutter, as well as various manual fabrication and assembly methods were investigated in the construction of the guitar prototypes. The lamination processes explored include low-temperature, heat-assisted pressure bonding, solvent and chemical welding, and contact adhesives. The project concluded …

Fabrication Of 3d Ultrafine Fibrous Protein Structures Via Freeze-Drying, Yiling Huang

Department of Textiles, Merchandising and Fashion Design: Dissertations, Theses, and Student Research

In this thesis, ultrafine fibrous 3D matrices were fabricated using three different proteins (soy protein, wool keratin, and chicken feather keratin) via freeze-drying. Protein matrices are preferable for tissue engineering compared to matrices made from synthetic material because of their similarity to native extracellular matrices. Due to their cell-binding motifs, natural proteins are also recognized as more biocompatible compared. Freeze-drying, which is a simple method used to produce 3D sponge matrices, was employed in this study to fabricate 3D fibrous matrices in a controlled manner. The inner structures of the 3D matrices fabricated ranged from film to fibers, and the …

Field-Limited Migration Of Li-Ions In Li-Ion Battery, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

The migration of Li-ions in lithium-ion battery cannot be simply described by Fick's second law; the interactions among ionic migration, field, and stress need to be taken into account when analyzing the migration of Li-ions. Using the theory of thermal activation process, the flux for ionic migration under concurrent action of electric field and mechanical stress is found to be a nonlinear function of the gradient of electric potential and the gradient of stress. Electric field can either accelerate or retard the growth of the lithiation layer, depending on polarity of the field.

Development Of A High Precision Quantum Dot Synthesis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Flow Cell, William Henry Lafferty

Master's Theses

Quantum dots show great potential for use as spectral converters in solar cells, lighting applications, and biological imaging. These applications require precise control of quantum dot size to maximize performance. The quality, size, and fluorescence of quantum dots depend on parameters that are difficult to control using traditional batch synthesis processes. An alternative, high precision process was developed for the synthesis of cadmium-selenide quantum dots using a microfluidic reactor and fluorescence flow cell. The process required creating separate cadmium and selenium precursors that were then mixed in a nitrogen environment at 17°C. Using an NE-300^® syringe pump, the solution …

Interaction Of Bn-Zro2-Sic Ceramics With Inclusions In Si-Killed Steel, Abhishek Kumar, Vivek Thapliyal, Jeffrey D. Smith

Materials Science and Engineering Faculty Research & Creative Works

Boron nitride (BN)-based ceramics are often used as containment refractory in thin-strip steel production. The interaction of this material (BN-ZrO₂-SiC: -MYCROSINT® SO43) was studied using a steel-inclusion system in a laboratory setup. Isothermal interaction tests were performed to evaluate the interaction of inclusions with this refractory. It was determined that corrosion of the BN refractory occurs through a dissolution mechanism and it was more severe in contact with steel compared to slag. A thermodynamic model was developed using FactSage to study the change in liquid steel/slag composition with refractory interaction. Thermodynamic predictions were in agreement with the experimental …

Biphilic Nanoporous Surfaces Enabled Exceptional Drag Reduction And Capillary Evaporation Enhancement, Xianming Dai, Fanghao Yang, Ronggui Yang, Xinyu Huang, William A. Rigdon, Xiaodong Li, Chen Li

Faculty Publications

Simultaneously achieving drag reduction and capillary evaporation enhancement is highly desired but challenging because of the trade-off between two distinct hydrophobic and hydrophilic wettabilities. Here, we report a strategy to synthesize nanoscale biphilic surfaces to endow exceptional drag reduction through creating a unique slip boundary condition and fast capillary wetting by inducing nanoscopic hydrophilic areas. The biphilic nanoporous surfaces are synthesized by decorating hydrophilic functional groups on hydrophobic pristine multiwalled carbon nanotubes. We demonstrate that the carbon nanotube-enabled biphilic nanoporous surfaces lead to a 63.1% reduction of the friction coefficient, a 61.7% wetting speed improvement, and up to 158.6% enhancement …

Modeling Of Thermal And Mechanical Behavior Of Zrb₂-Sic Ceramic After High Temperature Oxidation, Jun Wei, Lokeswarappa R. Dharani, K. Chandrashekhara, Greg Hilmas, William Fahrenholtz

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Growth And Properties Of Carbon Microcoils And Nanocoils, Muneaki Hikita, Robyn Bradford, Khalid Lafdi

Chemical and Materials Engineering Faculty Publications

Various types of coiled carbon filaments have been synthesized using chemical vapor deposition and other methods. These carbon filaments exhibit unique electrical and mechanical properties due to their versatile shapes and structures. To form coiled shapes, different types of catalyst compositions and reactive gases have been explored. Generally, coiled carbon filaments are classified by coil diameter and shape (e.g., microcoil and nanocoil). In this review, coiled carbon filaments are classified into three growth mechanism categories:

(1) bidirectional double helical growth;

(2) bidirectional twisted growth; and

(3) tip single helical or twisted growth.

Next, their synthesis methods and hypothetical growth mechanisms …

Slow Release Of Ions From Internalized Silver Nanoparticles Modifies The Epidermal Growth Factor Signaling Response, Kristen K. Comfort, Elizabeth I. Maurer, Saber M. Hussain

Chemical and Materials Engineering Faculty Publications

Due to their distinctive physiochemical properties, including a robust antibacterial activity and plasmonic capability, hundreds of consumer and medical products contain colloidal silver nanoparticles (AgNPs). However, even at sub-toxic dosages, AgNPs are able to disrupt cell functionality, through a yet unknown mechanism. Moreover, internalized AgNPs have the potential to prolong this disruption, even after the removal of excess particles. In the present study, we evaluated the impact, mechanism of action, and continual effects of 50 nm AgNP exposure on epidermal growth factor (EGF) signal transduction within a human keratinocyte (HaCaT) cell line. After AgNP expose, EGF signaling was initially obstructed …

Material | Adventure, Diana Wagner

Masters Theses

With the generous support of the RISD Grad Studies|Grant I traveled to London, England to deepen my thesis research of material libraries. This opportunity allowed me to visit the resources that inspired my enthusiasm for materials and to challenge the questions I posed in my thesis research, How we, artists and designers, learn from materials in the context of the library? The sources explored within this book highlight a growing community of academic and research based material collections in London, along with some exceptional exhibitions of materials and process in the context of the museum and archive.

The Stochastic Dynamics Of Tethered Microcantilevers In A Viscous Fluid, Brian A. Robbins, Milad Radiom, William A. Ducker, John Y. Walz, Mark R. Paul

Chemical and Materials Engineering Faculty Publications

We explore and quantify the coupled dynamics of a pair of micron scale cantilevers immersed in a viscous fluid that are also directly tethered to one another at their tips by a spring force. The spring force, for example, could represent the molecular stiffness or elasticity of a biomolecule or material tethered between the cantilevers. We use deterministic numerical simulations with the fluctuation-dissipation theorem to compute the stochastic dynamics of the cantilever pair for the conditions of experiment when driven only by Brownian motion. We validate our approach by comparing directly with experimental measurements in the absence of the tether …

Electrochemical And Spectroscopic Studies Of Ethanol Oxidation On Nano-Cubic Pt Modified By Tin Adatoms, Lu Rao, Bin-Wei Zhang, Yan-Yan Li, Yan-Xia Jiang, Shi-Gang Sun

Journal of Electrochemistry

The nano-cubic Pt modified by tin (Sn) was synthesized and used to investigate the role of this adatom played in the ethanol oxidation. The onset potential of ethanol oxidation was significantly shifted negatively which can be forward about 300 mV when the coverage of Sn (θSn)was 0.9. The electrtochemical in situ FTIR result demonstrated that the amount of CO₂ increased first, and then decreased with θSn increased, and reached the maximun when θSn was 0.38. Furthermore, the formation of acetic acid could be observed at very low potential (-0.05 V) after modifying Sn adatom, and the amount of acetic …

Preparation Of Pt/Dna-Mwcnts/Gc Electrode And Its Electrocatalytic Activity Toward H2O2 Reduction, Li-Li Fan, Li-Na Wu, Zhi-Yu Qu, Dan-Feng Liu, Jun-Ming Zhang, Si-Ming Fan, You-Jun Fan

Journal of Electrochemistry

The DNA-multi-walled carbon nanotubes (MWCNTs)/glassy carbon (GC) electrode was prepared by modifying the DNA functionalized MWCNTs composite on a GC electrode. A novel non-enzymatic H₂O₂ sensing electrode was fabricated by electrodepositing Pt nanoparticles on the DNA-MWCNTs/GC electrode. The modified electrodes were characterized by scanning electron microscope (SEM). The response properties of the sensing electrode to H₂O₂ were investigated by cyclic voltammetry and chronoamperometry. The results indicated that the sensing electrode exhibited a good linear relationship between response current and H₂O₂ concentration in the range of 0.04 ~ 18.07 mmol·L^-1 with …

Boosting Electrocatalytic Activity Of Nitrogen-Doped Graphene/Carbon Nanotube Composite For Oxygen Reduction Reaction, Yu Zhang, Jin-Song Hu, Wen-Jie Jiang, Lin Guo, Zi-Dong Wei, Li-Jun Wan

Journal of Electrochemistry

Developing low-cost catalysts with high electrocatalytic activity for oxygen reduction reaction (ORR) has recently attracted much attention because the sluggish ORR currently limits the performance and commercialization of fuel cells and metal-air batteries as well. Nitrogen doped carbon materials have been considered as a promising candidate for the replacement of high-cost and scarce Pt-based catalysts although their electrocatalytic activity still needs to be much improved. In this work, an improved nitrogen-doped graphene/carbon nanotubes composite (N-rGO/CNT) was developed as an efficient ORR electrocatalyst. It was found that the ORR activity of N-rGO/CNT composite could be significantly enhanced by introducing iron in …

Electrochemical Deposition Of Copt Alloy Thin Film And Its Abnormal Infrared Effects, Qing-Song Chen, Guo-Cong Guo, Shi-Gang Sun

Journal of Electrochemistry

Nanostructured CoPt alloy thin film was deposited on glassy carbon substrate (denoted as CoPt/GC) under cyclic voltammetric conditions. SEM studies demonstrated that the CoPt/GC was composed of nonuniform nanoparticles with an average size of 139 nm. The composition of the CoPt/GC was analyzed by energy dispersive X-ray spectroscopy (EDS), which depicts a Co:Pt ratio of ca. 3:5. In situ FTIR spectroscopy employing CO adsorption as a probe reaction revealed that the CoPt/GC exhibits abnormal infrared effects (AIREs). The unique anomalous IR features of CO adsorbed (CO_ad) on CoPt/GC consist in the complete inversion of the CO_ad IR …

Recent Progress In Heteroatoms Doped Carbon Materials As A Catalyst For Oxygen Reduction Reaction, Wei Ding, Xue Zhang, Li Li, Zi-Dong Wei

Journal of Electrochemistry

Developing catalytic materials for oxygen reduction reactions (ORR) with high performance and low cost has been one of the major challenges for large-scale applications of fuel cells. In this review, we summarize the recent progress in the heteroatoms doped carbon materials as a catalyst for the catalysis of ORR, with an emphasis on the universal origin of their catalytic mechanisms. The future prospects of the metal-free catalyst were to find precisely controlled doping methods, to explore the role of heteroatoms in the catalysis, and to generate more active catalysts with suitable nanostructure.

Fabrication Of Pattern Of Graphene Oxide And Au Nanoparticles By Microcontanct Printing Technique, Wen-Hui Pang, Xiao-Jian Xiao, Meng-Wei Ye, Kai-Chao Deng, Jing Tang

Journal of Electrochemistry

Graphene oxide (GO) was prepared by modified Hummers method. Using the GO solution as "ink", Au nanoparticles (AuNPs) and GO were transferred to the surface of ITO substrate modified with (3-aminopropyl) triethoxysilane (APTES/ITO) in a sequence. The transferred AuNPs and GO could form a uniform and dense composite pattern which was characterized by FE-SEM and AFM. Moreover, using the APTES/ITO substrate surface potential as zero, the sequences of the surface potential were APTES>GO>Au.

Fabrication And Characterization Of The Ni-Scsz Composite Anodes With A Cu-Lscm-Ceo2 Catalyst Layer In The Thin Film Sofc, Yao Lv, Bo Huang, Xi-Zhi Gu, Chun-Yi Hou, Yi-Xing Hu, Xiao-Yin Wang, Xin-Jian Zhu

Journal of Electrochemistry

Solid oxide fuel cell (SOFC) directly operating on hydrocarbon without external reforming has the potential of greatly speeding up the application of SOFCs for transportation. In this paper, a three-layer structure anode was fabricated by tape casting and screen printing method. The addition of Cu-LSCM-CeO₂ to the supported anode surface presented better performance running on H₂ and ethanol. The maximum power densities were 511 and 390 mW?cm^-2, respectively, running on H₂ and ethanol at 750 °C. No significant degradation was observed on the anode. Consequently, the Cu-LSCM-CeO₂ catalyst layer on the surface of the …

Influence Of Pt:Ru Ratio In Nanotubes Array Structures On The Electrocatalytic Activity Of Methanol Oxidation, Jin-Hua Yuan, Feng-Bin Wang, Xing-Hua Xia

Journal of Electrochemistry

Bimetallic PtRu nanotubes array electrodes (NTAEs) with varied Pt to Ru atomic ratios have been prepared by electrochemical codeposition in 3-aminopropyltri-methoxysilane modified porous anodic alumina (PAA) membranes. The structure and morphology of the catalysts were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Electrochemical results showed that the NTAEs with varied atomic ratios could be achieved by controlling the precursor concentration for deposition. The prepared nanoarrays composed of Pt or PtRu alloy promoted the mass-normalized activity toward the sluggish electrooxidation reaction of methanol due to the increased catalytic activity and real surface area, as well as the …

Electrochemistry Of Glucose Oxidase Modified On Porin-Phospholipid Biomimic Membrane, Kun-Qi Wang, Zuo-Ming Zhang, Wei Xing, Chang-Peng Liu, Xing Zhou

Journal of Electrochemistry

Biomimic membrane with nano-channels, which is made up of porin MspA and 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) is constructed on glassy carbon substrate, and glucose oxidase (GOD) is modified on it. The direct electrochemical reaction and electrocatalytic behavior to oxygen and glucose of GOD on the GOD/MspA-DMPC/GC electreode are expounded by the cyclic voltammetric method. The study shows that GOD immobilized on porin MspA and DMPC biomimic membrane displays direct and surface-controlled electrochemical reaction nearby formal potential (E0′) of the flavoprotein active centre (FAD/FADH), and the electrochemical reaction contains two electrons and two protons exchange in 0.1 mmol·L^-1 phosphate buffer solution (PBS) …

Effect Of Imidazole Ionic Liquids On The Electro-Oxidation Of P-Methoxy Toluene, Qiong Chen, Ying-Hong Zhu, Ying Zhu, Yan-Fang Li, Chun-An Ma

Journal of Electrochemistry

The interactions between four Imidazole ionic liquids (EMIMBF₄, BMIMBF₄, BMIMHSO₄, BMIMAc) and p-methoxy toluene were investigated by ultraviolet spectroscopy. The red shifts of absorption peak were obviously observed, and the fine structures of the spectroscopy were disappeared on the long wave district. p-MT producing stable excited state was benefit from the interaction with solvent molecules. The electro-oxidation behavious of p-MT were studied in the four ILs on platinum electrode by cyclic voltammetry (CV) and chronoamperometry (CP), and the diffusion coefficients (D) and activation energies (ED) were calculated. The results indicated that the electro-oxidation process …

Review Of Carbon Materials Energy Storage Mechanism In Lead-Carbon Battery, Le-Ying Wang, Hao Zhang, Chen Hu, Shu-Kai Zhang, Hai-Lei Zhao, Gao-Ping Cao, Wen-Feng Zhang, Yu-Sheng Yang, Xiao-Kang Lai

Journal of Electrochemistry

The traditional lead-acid batteries are mainly used for automobile and various internal combustion engine starting, wireless communication base stations and renewable energy storage; however, their negative plates are easily sulfated under partial-state-of-charge duty, then their charging capacity and cycle life are greatly reduced. Lead-carbon battery is a new type of lead-acid battery, in which a carbon material with high specific surface area and conductivity is added into a negative plate, and has excellent rate discharge performance and higher PSoC cycle life. Lead-carbon battery has a good application prospect in energy storage and hybrid electric vehicle, so these years the study …

Determination Of Folic Acid By Composite Film Electrode Modified With Poly-Alizarin Red And Multi-Walled Carbon Nanotubes, Xue-Ping Du, Tong-Fang Lou, Ying Dong, Jian-Ying Qu

Journal of Electrochemistry

The novel modified electrode was fabricated by electropolymerizing alizarin red onto the surface of multi-walled carbon nanotubes on glassy carbon electrode surface, which exhibited good electrocatalytic activity for folic acid. The experimental results showed that the reduction peak current of folic acid at -0.63 V was linear to its concentration over the range of 1.25×10^-6 ~ 4.00×10^-5 mol·L^-1 in the optimized experimental conditions (R = 0.9985). Test for recovery was carried out by standard addition method, and the recovery ratios were in the range of 92.0% ~ 102.0%. The modified electrode was prepared simply with excellent stability, …

Preparation And Electrochemical Behavior Of Pbo/Gn/Ac, Yun-Fang Gao, Yan-Ping Wang, Qiu-Shi Yao, Fu-Hua Wang, Dong-Lei Ren, Xin Xu

Journal of Electrochemistry

The lead oxide/graphene/activated carbon (PbO/GN/AC) composite materials were prepared by impregnating commercial activated carbon and graphene in saturated lead nitrate solution followed by calcination. The structures and morphologies of the composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that PbO crystals (about 200 nm) were dispersed uniformly on the surface of activated carbon and graphene. Electrochemical data indicate that the composite exhibited good electrochemical performances. The PbO/GN/AC composite possessed the higher over-potential of hydrogen evolution and the high specific capacitance of 312.6 F·g^-1, while the internal resistance …

Electro-Catalytic Properties Of Β-Pbo2/Sb-Sno2/Ti Electrode On Phenol Oxidation, Peng Li, Yue-Min Zhao, Li-Zhang Wang, Yan-Le Zhang, Zhao-Qing Lu

Journal of Electrochemistry

The combination technology of brush pyrolysis and electroplating was employed in the preparation of β-PbO₂/Sb-SnO₂/Ti electrode. X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) results showed that the Sb-SnO₂ as an interlayer would restrain the formation of lead fluoride and the crystallization degree on the electrode surface could be as high as 100%. The grain size was calculated by Scherrer formula to be 25.2 nm and the agglomeration of lead dioxide was effectively eliminated. The potential span of diffusion control phase, oxygen evolution potential, Tafel slope for the β-PbO₂/Sb-SnO₂/Ti electrode during …

On The Origin Of The Errors Of IK As Estimated From K-L Equation In Rotating Disk Electrode System, Wei Chen, Ling-Wen Liao, Zheng-Da He, Yan-Xia Chen

Journal of Electrochemistry

Rotating disk electrode system is mainly used to study the kinetics of reactions whose reactants have very low solubility in the electrolyte. For an irreversible reaction, Koutecky-Levich equation (K-L Eq.) is frequently used to deduce the kinetic current i_k). Since K-L Eq. is derived based on the assumption that a system should conform the steady-state diffusion conditions, the data recoded from the actual system which deviates from such a condition, great error may be induced for the i_k estimated. In this work, polarization curves for oxygen reduction reaction at polycrystalline Pt electrode recorded in solutions with various …

Effect Of Plasticizer On Oxygen Permeability Of Cast Polylactic Acid (Pla) Films Determined Using Dynamic Accumulation Method, Kurniawan Yuniarto, Bruce A. Welt, Aris Purwanto, Hadi Karia Purwadaria, Ayman Abdellatief, Titi C. Sunarti, Setyo Purwanto

Journal of Applied Packaging Research

Polylactic acid (PLA) is becoming an increasingly important biopolymer for packaging applications. PLA brittleness limits its applicability. This study evaluated PLA properties with increasing amounts of added polyethylene glycol (PEG) plasticizer. Oxygen transmission rate (OTR) of cast films was determined using the newly available Dynamic Accumulation (DA) method. Arrhenius temperature sensitivity of OTR and polymer Permeability was also determined. Permeability of neat PLA is 4.848 ml mm (STP)/m² s kPa; hence, 4.84 ml mm (STP)/m² s kPa, 4.07 ml mm (STP)/m² s kPa and 5.42 ml mm (STP)/m² s kPa by adding PEG 1 %, 5% …

Polycrystalline Iii-Nitrides, Michael J. Callahan, Buguo Wang, John S. Bailey

AFIT Patents

This invention provides a process for producing high-purity dense polycrystalline III-nitride slabs. A vessel which contains a group III-metal such as gallium or an alloy of group III-metals of shallow depth is placed in a reactor. The group III-metal or alloy is heated until a molten state is reached after which a halide-containing source mixed with a carrier gas and a nitrogen-containing source is flowed through the reactor vessel. An initial porous crust of III-nitride forms on the surface of the molten III-metal or alloy which reacts with the nitrogen-containing source and the halide-containing source. The flow rate of the …