Engineering Commons^™

Effect Of Activated Carbon On The Performance Of A Solar Thermal Adsorptive Refrigerator (Star) Using Activated Carbon-Ethanol, Joshua Romo

Honors Theses

The Solar Thermal Adsorptive Refrigerator (STAR) project at the University of Dayton seeks to bridge sustainability and the need for reliable refrigeration in developing communities. Cost-effective construction, operation, and maintenance as well as the use of a sustainable adsorption pair, activated carbon-ethanol, give STAR great potential in the realm of humanitarian engineering. This project explores the effect of using two activated carbon brands, 8x16 and CocoPlus, on the cyclic performance of the STAR system. Although both brands have similar specifications given by the manufacturer, one (8x16) inhibited successful performance while the other (CocoPlus) enabled it. This project highlights both the …

Wavelet Transform On Digital Rainbow Hologram Based On Spectral Compression For Quality Enhancement In 3d Display Media, Ucuk Darusalam, Panca Dewi Pamungkasari

Makara Journal of Technology

A digital rainbow hologram (DRH) is a potential next-generation three-dimensional display media for the development of modern and smart electronics devices. It is one of the methods that can support the characteristic whereby a realistic display media occupies the space that the real object would have occupied. Since a rainbow hologram records a large amount of spatial or temporal frequency component from the object that represents the rainbow spectrum, a large amount of information needs to be decoded digitally. In this paper, to reconstruct a DRH, we propose a novel method based on the modulation of red, green, and blue …

Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu

Mechanical & Aerospace Engineering Theses & Dissertations

The off-axis compressive behavior of ice-templated ceramic was analyzed using experimental results and micro-mechanical model simulation. Ice-templated ceramics is a versatile processing technique used to manufacture anisotropic ceramic foam by exploiting the anisotropic growth characteristics and lamellar morphology. The ice-templating process results in processing-structure-property relationships determined by the microstructure. The processed alumina samples which were later manufactured by water jet machine from the freeze casting were tested under quasi-static off-axis loading conditions and were used to determine the mechanical properties of the material. Digital image correlation (DIC) was used to measure the strain response of ice-templated ceramic under off-axis loading. …

Effect Of Alkali On The Efficiency And Reliability Of Cu(In,Ga)Se2 Solar Cells, Shankar Karki

Physics Theses & Dissertations

The incorporation of alkali metal has contributed tremendously in a bid to realize greater than 20% efficient Cu(In,Ga)Se₂(CIGS) solar cells. Achieving high efficiency is one key parameter for the success of a photovoltaic technology but so is its long-term stability. In this thesis, the relationship between the performance of alkali treated Cu(In,Ga)Se₂ solar cells and their physicochemical, electronic and structural properties are explored through a comparative study between standard devices and alkali (K, Rb) treated devices. The alkali treated devices tend to have a lower concentration of E_v+0.98 eV trap, higher majority carrier concentration and …

Data Fusion Method Based On Adaptive Kalman Filtering, Bernadus Herdi Sirenden

Makara Journal of Technology

This paper discusses data fusion methods to combine the data from a rotary encoder and ultrasonic sensor. Both sensors are used in a micro-flow calibration system developed by the Research Center of Metrology LIPI. The methods studied are hierarchical data fusion and Kalman filtering. Three types of Kalman filters (KFs) are compared: the conventional Kalman filter and two adaptive Kalman filters. Moreover, a method to combine the uncertainty results from KF in hierarchical data fusion is proposed. The aim of this study is to find appropriate methods of data fusion that can be implemented in micro-flow calibration systems. Data from …

Geometric Effects Of Open Hollow Hydroxyapatite Microspheres Influence Bone Repair And Regeneration In Sprague Dawley Rats, Youqu Shen, M. N. Rahaman, Yongxian Liu, Yue-Wern Huang

Materials Science and Engineering Faculty Research & Creative Works

Effective regeneration of bone defects caused by trauma or chronic diseases is a significant clinical challenge. Bone deficiency is overcome using treatments that rely on bone regeneration and augmentation. While various treatments have been investigated with encouraging results, complete and predictable bone reconstruction is often difficult [1]. Synthetic bone grafts have advantages such as consistent quality, safety, and good tissue tolerance. They usually function as inert or osteoconductive implants. Encouraging results from synthetic grafts have been reported. For instance, hollow hydroxyapatite (HA) microspheres showed the ability to facilitate bone repair in rats with non-healing calvarial defects [2,3]. However, new bone …

Characterization Of Mgal₂O₄ Sintered Ceramics, Nina Obradovic, William Fahrenholtz, Suzana Filipovic, Cole Corlett, Pavle Dordevic, Jelena Rogan, Predrag J. Vulic, Vladimir Buljak, Vladimir Pavlovic

Materials Science and Engineering Faculty Research & Creative Works

Single phase MgAl₂O₄ was made from a one-to-one molar ratio of MgO and Al₂O₃ powders mixed using ball-milling. Mixtures of MgO and Al₂O₃ were subsequently treated in planetary ball mill for 30, 60, 90 and 120 minutes in air. The aim of this study was to examine phase composition, microstructure, and densification behavior of sintered specimens. After sintering in dilatometer at 1500 °C, the powder was converted to single phase MgAl₂O₄. The results show that mechanical activation improved the densification behavior of MgAl₂O₄ sintered …

A Dual Nanostructured Approach To Sers Amenable To Large-Scale Production, Kory Brian Castro

Chemistry & Biochemistry Theses & Dissertations

A SERS device was made using a dual-nanostructured surface comprised of silver nanoparticle and silver nanowires. The ability of each nanostructure to produce a uniform surface was characterized and the surface-enhanced Raman scattering (SERS) response of the resulting surfaces were examined using the reporter molecule 4-aminothiolphenol (ATP) and a 638 nm excitation laser.

A synthetic method was developed to produce silver nanowires with lengths of ~20 μm and diameters of ~100 nm with a narrow size distribution. The method utilized a simple, one-pot synthesis that is amenable to large-scale production. A selective precipitation method was used to the isolate the …

Sorption-Based Energy Storage Systems: A Review, Kyaw Thu, Nasruddin Nasruddin, Sourav Mitra, Bidyut Baran Saha

Makara Journal of Technology

Mismatched timing between the supply and demand of energy calls for reliable storage systems. Energy storage systems have become further significant with the widespread implementation of renewable energy. These systems can mitigate problems that are often associated with renewable energy sources such as supply unreliability while meeting the de-mand during peak hours. Energy can be stored in various forms, yet storage systems can be generally grouped based on their output forms, namely (i) electricity and (ii) heat or thermal energy. Electrical energy is the most convenient and effective form since it can power almost all modern devices. However, the electricity …

Nano-Scale Rare Earth Distribution In Fly Ash Derived From The Combustion Of The Fire Clay Coal, Kentucky, James C. Hower, Dali Qian, Nicolas J. Briot, Eduardo Santillan-Jimenez, Madison M. Hood, Ross K. Taggart, Heileen Hsu-Kim

Center for Applied Energy Research Faculty and Staff Publications

Fly ash from the combustion of eastern Kentucky Fire Clay coal in a southeastern United States pulverized-coal power plant was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). TEM combined with elemental analysis via energy dispersive X-ray spectroscopy (EDS) showed that rare earth elements (REE; specifically, La, Ce, Nd, Pr, and Sm) were distributed within glassy particles. In certain cases, the REE were accompanied by phosphorous, suggesting a monazite or similar mineral form. However, the electron diffraction patterns of apparent phosphate minerals were not definitive, and P-lean regions of the glass consisted …

The Effect Of Defects And Surface Modification On Biomolecular Assembly And Transport, Haneen Martinez

Nanoscience and Microsystems ETDs

Nanoscale transport using the kinesin-microtubule (MT) biomolecular system has been successfully used in a wide range of nanotechnological applications including self-assembly, nanofluidic transport, and biosensing. Most of these applications use the ‘gliding motility geometry’, in which surface-adhered kinesin motors attach and propel MT filaments across the surface, a process driven by ATP hydrolysis. It has been demonstrated that active assembly facilitated by these biomolecular motors results in complex, non-equilibrium nanostructures currently unattainable through conventional self-assembly methods. In particular, MTs functionalized with biotin assemble into rings and spools upon introduction of streptavidin and/or streptavidin-coated nanoparticles. Upon closer examination of these structures …

Limit Equilibrium Method-Based Shear Strength Prediction For Corroded Reinforced Concrete Beam With Inclined Bars, Yafei Ma, Baoyong Lu, Zhongzhao Guo, Lei Wang, Hailong Chen, Jianren Zhang

Mechanical Engineering Faculty Publications

Shear strength is a widely investigated parameter for reinforced concrete structures. The corrosion of reinforcement results in shear strength reduction. Corrosion has become one of the main deterioration factors in reinforced concrete beam. This paper proposes a shear strength model for beams with inclined bars based on a limit equilibrium method. The proposed model can be applied to both corroded and uncorroded reinforced concrete beams. Besides the tensile strength of longitudinal steel bars, the shear capacity provided by the concrete on the top of the diagonal crack, the tensile force of the shear steel at the diagonal crack, the degradation …

Could 79 People Solarize The U.S. Electric Grid?, Joshua M. Pearce, Emily Prehoda

Department of Materials Science and Engineering Publications

Although wealth inequality has many established negatives, this study investigates a potential positive, unprecedented wealth concentration makes it possible for solutions to large and seemingly intractable problems to be deployed by convincing a relatively small number of individuals to invest. In order to probe this potential outcome of inequality, this study quantifies the number of people necessary to radically reduce the greenhouse gas emissions responsible for global climate destabilization from the U.S. electric grid, which is one of the largest sources of emissions. Specifically, this study determined that 1544 GW of solar photovoltaic (PV) technology must be deployed to eliminate …

5th Ic4n Book Of Abstracts, Efstathios Meletis, Nikolaos Kanellopoulos, Constantin Politis, Wolfram Schommers

International Conference from Nanoparticles and Nanomaterials to Nanodevices and Nanosystems - Archive

IC4N is a highly interdisciplinary conference focusing on all aspects of nanoscience and nanotechnology addressing global problems in energy, environment and human health. As in previous editions of this highly popular conference series, the overarching goal is to combine a high quality of scientific dialogue with a relaxing environment. This is a unique opportunity for both senior and junior researchers to meet, interact, and stimulate collaborations on a global scale. A number of Plenary, Keynote and invited lectures are planned by renowned scientists from all over the world, making IC4N an international nano forum of the highest quality.

Proceedings published …

Biodegradable Composite Scaffold For Repairing Defects In Load-Bearing Bones, D. E. Day, Ali Mohammadkhah

Materials Science and Engineering Faculty Research & Creative Works

A tissue scaffold for repair and regeneration of bone hard tissue or muscle, skin, or organ soft tissue, including load-bearing bone tissue, the scaffold comprising a core of biocompatible, biodegradable inorganic glass fibers; and a biocompatible, biodegradable, flexible polymer film surrounding the core and adhered to the core.

Concentration Flow Cells For Efficient Salinity Energy Recovery With Carbonized Peat Moss And Molybdenum Disulfide Electrodes, Haihui Zhu

LSU Master's Theses

The globally extractable salinity gradient (SG) energy from the mixing of seawater and river water is estimated to be 3% of worldwide electricity consumption. Here we applied carbonized peat moss (CPM) electrodes and molybdenum disulfide (MoS₂) electrodes to a concentration flow cell that is capable of harvesting SG energy based on the electrode (pseudo-)capacitance together with the Donnan potential. The CPM electrodes were made from the visually inexhaustible peat moss by a facile pyrolysis process. With two identical CPM electrodes and a cation-exchange membrane, the cell produced a peak power density of 5.33 W m^-2 and an …

Displacement Damage Effects In Gesn Light Emitting Diodes, Kevin K. Choe

Theses and Dissertations

Potential future use on Earth-orbiting satellites calls for investigation into the suitability of GeSn based photonic devices in high energy proton environments. The electroluminescence (EL) intensity of Ge1-xSnx (x = 0, 0.02, 0.069, and 0.094) light emitting diodes was measured before and after irradiation by 2 MeV protons at relatively high fluence levels. The results showed that GeSn devices with higher Sn content were up to 10 times more resistant against proton displacement damage than the pure Ge (x = 0) devices. As Sn concentration increased, the band gap decreased, and V-P hole trap energy level moved further from the …

Improved Fabrication For Micromirror Arrays, Enoc Flores

Theses and Dissertations

Micromirror devices which consisted of one SU-8 2050 layer, two different exposures, and a series of metal depositions were constructed and evaluated. By varying the exposure, a micromirror structure was fabricated with different thicknesses, a ratio of 1.083 µm/(mJ/cm²) was found. The initial design consisted of four layers. The pillar was made of one SU-8 layer, and the top portion had three layers in the following order: gold, SU-8, and gold. This design could not be released and did not have characteristics of a flat and conformal reflective surface. Several variations of the initial design were explored and …

Characterization Of Metal Contacts On Hydrothermally Synthesized Uranium Dioxide For Novel Semiconductor Applications, Tory E. Robinson

Theses and Dissertations

This research is focused on determining which metals or combinations of metals form effective electrical contacts on hydrothermally synthesized UO2 substrates to allow for additional work in characterization of the material as well as the feasibility of its use in semiconductor devices such as solid-state neutron detectors. A methodology was established for selection of candidate metals. Target mixtures composed of Au, Ag, Pt, and Mg were chosen along with several single-metals. Thin metal films were deposited onto tungsten probe tips and hydrothermally synthesized UO2 samples to allow for analysis of mechanical and deposited contact to the substrates through I-V measurements.

3-D Multifunctional Sensors Fabricated On Fiber Tips Using A Two-Photon Polymerization Process, Jonathan W. Smith

Theses and Dissertations

This thesis conducts research involving designing, fabricating, and testing optical fiber tip refractive index sensors. The fabrication process used for these sensors is a two-photon polymerization process utilizing a photo sensitive polymer. Unlike planar lithography, this fabrication process allows the creation of arbitrary shapes with a great degree of freedom. Three different fiber tip sensors were fabricated and tested. The first is a flat surfaced single cavity Fabry-Pérot interferometer (FPI) device, the second is a flat surfaced double cavity FPI device, and the final is a confocal surfaced double cavity FPI device. These sensors are tested for thermal radiation and …

Conducting Polymer Based Gel Electrolytes For Ph Sensitivity, Aditya Jagannath Kashyap

USF Tampa Graduate Theses and Dissertations

The evaluation of concentration of ions and molecules with the help of biosensors have been regarded as an emerging technology. Bio and chemical sensors have a variety of applications in the field of medicine, military, environmental and food industries alike. With an estimated investment growth of over 4.31% in the development of pH sensors in the next five year, the objective of a developing a robust measurement system is all the more required. The scope of this research is to evaluate the ability of conducting polymer-based gel electrolytes for pH sensitivity, as a function of the transistor characteristics using an …

Bridge Deck Delamination Segmentation Based On Aerial Thermography Through Regularized Grayscale Morphological Reconstruction And Gradient Statistics, Chongsheng Cheng, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Environmental and surface texture-induced temperature variation across the bridge deck is a major source of errors in delamination detection through thermography. This type of external noise poises a significant challenge for conventional quantitative methods such as global thresholding and k-means clustering. An iterative top-down approach is proposed for delamination segmentation based on grayscale morphological reconstruction. A weight-decay function was used to regularize the reconstruction for regional maxima extraction. The mean and coefficient of variation of temperature gradient estimated from delamination boundaries were used for discrimination. The proposed approach was tested on a lab experiment and an in-service bridge deck. The …

Creep Of Nextel 720/Alumina Ceramic Matrix Composite With Diamond-Drilled Effusion Holes At 1200°C In Air And In Steam, Megan L. Harkins

Theses and Dissertations

A recent study evaluated tensile stress-strain and tensile creep behavior of an oxide-oxide composite (Nextel™720/alumina) with laser-drilled effusion holes at 1200°C. It was determined that the presence of laser-drilled holes degraded the mechanical properties and performance of the CMC as a result of damage caused to the composite microstructure by the laser drilling process. Based on these results, the present effort sought to assess the effects of diamond-drilled holes on the mechanical behavior of this CMC. Tensile properties of the N720/A composite at 1200°C in laboratory air were unaffected by the presence of an array of 17 diamond-drilled effusion holes. …

Ballistic Evaluation Of Carbon Nanotube Sheet Material In Multifunctional Applications, Casey M. Keilbarth

Theses and Dissertations

Significant development of carbon nanotubes has occurred since they were first studied in the 1990's. Attempts to capture the phenomenal molecular properties in practical applications are gaining ground as new methods of producing CNTs have been developed. This thesis sought to determine if the addition of commercially produced CNT sheets to thin carbon fiber panels improved the ballistic properties of the panel. The difference between 0 and 4 CNT sheets was studied. The hypothesis was that inte- grating CNT sheets into the laminate would increase the projectile energy absorbed by the panel and reduce the damage to the panel incurred …

Scaling Film Cooling Adiabatic Effectiveness With Mass Transfer And Thermal Experimental Techniques, Luke J. Mcnamara

Theses and Dissertations

With increasing engine temperatures, it is becoming more important to design effective film cooling schemes. Low temperature, large scale tests are often implemented in the design process to reduce cost and complexity. A nondimensional adiabatic effectiveness can be used as an indication of the performance of a film cooling scheme. However, the coolant flow rate must be properly scaled between the low temperature tests and engine temperatures to accurately predict film cooling effectiveness. This process is complicated by gas property variation with temperature. Tests are commonly conducted using thermal measurement techniques with infrared thermography (IR), but the use of pressure …

Evaluation Of Guar Gum As A Novel Adsorbent, Philicia Geiser

Theses and Dissertations

Guar gum (GG) is a promising product increasingly used in a variety of industries. It is nontoxic, inexpensive, and biodegradable. This research evaluated novel approaches using GG as an adsorbent for aromatic organic water contaminants. The application of GG demonstrated some effectiveness against all contaminants tested. Two brands of GG were tested using 5 different GG treatment strategies. Various experiments demonstrated nearly complete removal of Allura Red dye, Brilliant Blue dye, Erythrosine B dye, Methylene Blue dye, Tartrazine dye, and 2,4-dinitrotoluene; additionally, 78% adsorption was observed for Fast Green dye. GG typically removed less than 10% of toluene, which rapidly …

Analysis And Design Of Modular Overhead Protection System Utilizing Readily Available Materials, Zachary J. Spranger

Theses and Dissertations

This research investigated passive overhead protective measures for existing facilities in an urban environment that are vulnerable to enemy munitions fire. A new modular structural system was designed utilizing commercially available construction material consisting of structural tubing, scaffolding clamps, base plates, and simple roofing components. Structural analysis software was used to model nine modular structures to understand the relationship between the load bearing capacity of the structural members and overall dimensions of the system. Environmental variables for the models were set to the Parwan Province in Afghanistan; this region presents worst-case scenarios both for environmental factors and threat of enemy …

Direct Numerical Simulation Of Roughness Induced Hypersonic Boundary Layer Transition On A 7° Half-Angle Cone, Tara E. Crouch

Theses and Dissertations

Direct numerical simulation (DNS) computational fluid dynamic (CFD) calculations were performed on a 30° slice of 7° half-angle cones with increasing nose radii bluntness at Mach 10 while simulating a distributed roughness pattern on the cone surface. These DNS computations were designed to determine if the non-modal transition behavior observed in testing performed at the Arnold Engineering Development Center (AEDC) Hypervelocity Wind Tunnel 9 was induced via distributed surface roughness. When boundary layer transition is dominated by second mode instabilities, an increase in nose radius delays the transition location downstream. However, blunt nose experiments indicated that as the nose radius …

Interlaminar Shear Performance Of High Temperature Composites, Tyler A. Wallis

Theses and Dissertations

Interlaminar shear properties of a high temperature polymer matrix composite (HTPMC) and a ceramic matrix composite (CMC) were evaluated at elevated tempera- ture. Two variants of the HTPMC were studied. Both consisted of a high-temperature polyimide (AFR-PE-4) matrix reinforced with Astroquartz-III pre-impregnated glass fabric woven in an eight-harness-satin weave. The first HTPMC variant also contained stainless steel foil at the midplane, while the second HTPMC variant did not. The interlaminar shear strength (ILSS) of both variants of the HTPMC was evaluated at 204°C in laboratory air. The addition of the stainless steel foil resulted in significant loss of ILSS for …

Application Of Computational Tools To Spaghetti-Based Truss Bridge Design, Jin Xu, Jiliang Li, Nuri Zeytinoglu, Jinyuan Zhai

ASEE IL-IN Section Conference

Application of Computational Tools to Spaghetti-Based Truss Design

Statics and Strength of Materials are two foundational courses for Mechanical/Civil Engineering. In order to assist students in better understanding and applying concepts to a meaningful design task, SolidWorks and theoretical calculation were used for a spaghetti-bridge design contest with the constraints of given maximum weight and allowable support-material weight. As the first step of this iterative designing process, both extrude feature and structural member were introduced to model planar bridge trusses. Then SolidWorks’ Statics module was used to run FEA analysis of the structural performance in efforts to optimize the …