Engineering Commons^™

Complex Of 3-Amino-1,2,4-Triazole And Na2Wo4 As An Inhibitor For Brass Corrosion, Qun-Jie Xu, Chun-Xiang Li, Yu-Hong Ni, Guo-Ding Zhou

Journal of Electrochemistry

AC impedance and polarization methods were used to study the inhibition effect of ATA and the complex of ATA and Na₂WO₄ for brass corrosion in 3% NaCl solution.The results indicated that ATA had inhibition effect for brass corrosion.ATA showed the best inhibition effect for brass corrosion at the ATA concentration of 7.5 mg·L^-1,and the inhibition efficiency was 87.46%.At the ATA concentration of 7.5 mg·L^-1 and at the Na₂WO₄ concentration of 0.15 mg·L^-1,the complex showed optimum inhibition effect for brass corrosion,and also showed synergistic effect and the inhibition efficiency reached …

The Effective Slip Length And Vortex Formation In Laminar Flow Over A Rough Surface, Anoosheh Niavarani, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The flow of viscous incompressible fluid over a periodically corrugated surface is investigated numerically by solving the Navier–Stokes equation with the local slip and no-slip boundary conditions. We consider the effective slip length which is defined with respect to the level of the mean height of the surface roughness. With increasing corrugation amplitude the effective no-slip boundary plane is shifted toward the bulk of the fluid, which implies a negative effective slip length. The analysis of the wall shear stress indicates that a flow circulation is developed in the grooves of the rough surface provided that the local boundary condition …

Modulated Nanopores Using Pulse Anodization On Thin Aluminum, Mahesh Babu Gunukula

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nanoporous anodic aluminum oxide has traditionally been made in one of two ways: "Mild Anodization (MA)" or "Hard Anodization (HA)". The former method produces self-ordered pore structures but it is slow and only works for a narrow range of processing conditions; the latter method, which is widely used in the aluminum industry, is faster but it produces films with disordered pore structures. Here we report a novel approach termed "pulse anodization" that combines the advantages of the MA and HA processes. By designing the pulse sequences it is possible to control both the composition and pore structure of the anodic …

Design And Fabrication Of A Small Prototype Airframe Structure, Kimberly Lynn Clark

UNLV Theses, Dissertations, Professional Papers, and Capstones

This project called for a first-generation prototype aircraft with hovering capabilities that was lightweight. The focus of this study was to design a small low-cost prototype composite airframe that meets specified requirements, analyze structures using finite element analysis and mechanical testing, and construct a prototype using proven composite manufacturing techniques. One fuselage, one wing, and several engine nacelles were designed and fabricated. Several design and fabrication methods and materials were analyzed, with focus given to the nacelles, and recommendations were provided for the manufacture of the first generation airframe based on time, weight, and cost.

Droplet Assisted Self-Assembly Of Semiconductor Nanostructures, Kimberly Annosha Sablon

Graduate Theses and Dissertations

There is increasing interest in quantum dot (QD) structures for a plethora of applications, including optoelectronic devices, quantum computing and energy harvesting. While strain driven surface diffusion via stranski-krastanow (SK) method has been commonly used to fabricate these structures, a more recent technique, droplet epitaxy (DE) does not require mismatch strain and is therefore much more flexible in the combination of materials utilized for the formation of QDs.

As reported in this work, a hybrid approach that combines DE and SK techniques for realizing lateral ordering of QDs was explored. First, the droplet formation of various materials was discussed and …

Freeze-Spray Deposition Of Layered Alumina/Zirconia Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Freeze-spray deposition (FSD) method is described for rapid fabrication of layered composites with controlled layer thickness and uniform microstructure. The graded alumina/zirconia composites are fabricated by FSD of ceramic slurries followed by freeze drying. Aqueous slurries with glycerol addition are sprayed on a cooled substrate using an automated 3D gantry system. Processing parameters such as viscosity of the ceramic slurries, composition and thickness of deposited layers as well as sintering conditions are investigated to optimize the fabrication process. Microstructural analysis of the fabricated composites revealed uniform and crack-free transitional layers indicating a strong interfacial bonding between the layers.

Gossamer Albatross, Steve Elliott

ERAU Prescott Aviation History Program

Steve Elliott was active in the hobby of hang gliding, and was invited to join the Gossamer Albatross team in 1979. He assisted in its development and testing, and was there in a Zodiac raft when it became the first human powered aircraft to cross the English Channel and win the £100,000 Kremer Prize.

Computational Study Of Pristine And Titanium-Doped Sodium Alanates For Hydrogen Storage Applications, Gopi Krishna Phani Dathar

Doctoral Dissertations

The emphasis of this research is to study and elucidate the underlying mechanisms of reversible hydrogen storage in pristine and Ti-doped sodium aluminum hydrides using molecular modeling techniques. An early breakthrough in using complex metal hydrides as hydrogen storage materials is from the research on sodium alanates by Bogdanovic et al., in 1997 reporting reversible hydrogen storage is possible at moderate temperatures and pressures in transition metal doped sodium alanates. Anton reported titanium salts as the best catalysts compared to all other transition metal salts from his further research on transition metal doped sodium alanates. However, a few questions remained …

Characterizing Twin Structure And Magnetic Domain Structure Of Ni-Mn-Ga Through Atomic Force, Matthew Reinhold

McNair Scholars Research Journal

Ni-Mn-Ga is a ferromagnetic shape memory alloy that deforms by twin boundary motion. The magneto-mechanical properties depend strongly on the twin microstructure. A thermomechanical treatment was applied to a Ni-Mn-Ga single crystal with coexisting 10M and 14M martensite structures to create twin boundaries and align the short crystallographic c direction preferentially perpendicular to the surface. The resulting twin structure was characterized using atomic force microscopy (AFM) to obtain the surface relief caused by twinning. Magnetic force microscopy (MFM) was used to find the direction of easy magnetization (which coincides with the crystallographic c direction) of each twin. Among 18 possible …

Neutron Structural Studies On The Superconducting (Nd₁₋ₓcax)(Ba₁.₆La₀.₄)Cu₃Oz System, Amish G. Joshi, R. G. Kulkarni, William B. Yelon, Ram Prasad, M. R. Gonal

Physics Faculty Research & Creative Works

We have investigated the influence of Ca ion substitution on the structural and superconducting properties of (Nd1−xCax)(Ba1.6La0.4)Cu3Oz system. Magnetization, x-ray diffraction, and neutron diffraction studies have been carried out on a series of compounds with x=0.0-0.6. The superconducting transition temperature Tc, determined from magnetization measurements, increases with increasing Ca2+ substitution. Neutron diffraction studies reveal that these compounds crystallize in a tetragonal structure (space group P4/mmm). A detailed analysis of the neutron diffraction data reveals that Ca and La ions are intermixed at the nominal Ba and Nd sites. While a major fraction of Ca ions occupy the usual Nd site, …

Gravity Effects On Capillary Flows In Sharp Corners, Enrique Ramé, Mark M. Weislogel

Mechanical and Materials Engineering Faculty Publications and Presentations

We analyze the effect of gravity on capillary flows in sharp corners. We consider gravity perpendicular and parallel to the channel axis. We analyze both steady and unsteady flows. In the steady analysis the main result is a closed form expression for the flow rate as a function of the two gravity components. Good agreement with steady experiments is offered as support of the model. The unsteady analysis is restricted to “small” values of the two gravity parameters and is accomplished using a similarity formulation. The similarity coefficients of the gravity corrections are fully determined by the coefficients of the …

Improved Predictive Power Control Of Cdma System In Rayleigh Fading Channel, Adit Kurniawan, Iskandar Iskandar, Sayid Machdar

Makara Journal of Technology

In this paper an improved prediction-based power control is proposed for code division multiple access (CDMA) systems in Rayleigh fading channel environments. One of the most serious problems which degrades the performance of power control algorithm is the effect of feedback delay. To overcome the effect of feedback delay, power control needs to employ prediction algorithm which utilises the correlation property of the past channel samples measurements to predict the future sample values. In CDMA power control, however, the correlation property of channel measurements is destroyed because the transmit power is continuously updated for each power control interval. The prediction …

On The Performance Of Svd-Dwt Based Digital Video Watermarking Technique With Semi-Blind Detector, Tarzan Basaruddin, Della Maulidiya

Makara Journal of Technology

On the Performance of SVD-DWT Based Digital Video Watermarking Technique with Semi-Blind Detector. This paper presents a watermarking technique for digital video. The proposed scheme is developed based on the work of Ganic and Chan which took the virtue of SVD and DWT. While the previous works of Chan has the blind detector property, our attempt is to develop a scheme with semi-blind detector, by using the merit of the DWT-SDV technique proposed by Ganic which was originally applied to still image. Overall, our experimental results show that our proposed scheme has a very good imperceptibility and is reasonably robust …

Lipid Production From Microalgae As A Promising Candidate For Biodiesel Production, Arief Widjaja

Makara Journal of Technology

Recently, several strains of microalgae have been studied as they contain high lipid content capable to be converted to biodiesel. Fresh water microalgae Chlorella vulgaris studied in this research was one of the proof as it contained high triacyl glyceride which made it a potential candidate for biodiesel production. Factors responsible for good growing of microalgae such as CO2 and nitrogen concentration were investigated. It was found that total lipid content was increased after exposing to media with not enough nitrogen concentration. However, under this nitrogen depletion media, the growth rate was very slow leading to lower lipid productivity. The …

Finite Element Model Of A Tennis Racket, Sayali Shashikant Kapatkar

Mechanical & Aerospace Engineering Theses & Dissertations

An explicit finite-element (FE) model of a tennis racket and string was produced in NASTRAN/PATRAN. MSC/NASTRAN is a general-purpose FEA program capable of solving a wide variety of engineering problems such as linear static analysis, static analysis with geometric and material with nonlinearities, transient analysis with geometric and material nonlinearities. A finite element racket model was used to study the engineering characteristics that affect the "sweet spot" of a te1mis racket. A similar model was simulated by creating a tennis racket, a tennis ball and a string-bed, and it was validated against MADYMO (Mathematical Dynamic Model) data.

The MADYMO validation …

Environmental Remediation Full-Scale Implementation: Back To Simple Microbial Massive Culture Approaches, Agung Dhamar Syakti, Mohamad Yani

Makara Journal of Technology

Using bioaugmentation and biostimulation approach for contaminated soil bioremediation were investigated and implemented on field scale. We combine those approaches by culturing massively the petrophilic indigenous microorganisms from chronically contaminated soil enriched by mixed manure. Through these methods, bioremediation performance revealed promising results in removing the petroleum hydrocarbons comparatively using metabolite by product such as biosurfactant, specific enzymes and other extra-cellular product which are considered as a difficult task and will impact on cost increase.

Preparation Of Radioactive Gold Nanoparticle By Neutron Activation, Rohadi Awaludin

Makara Journal of Technology

Preparation of Radioactive Gold Nanoparticle by Neutron Activation. It was reported that gold nanoparticle could be used for cancer therapy using thermal effect. It is possible to kill cancer cells using radiation of radioisotope. Study on preparation of radioactive gold by neutron activation at central irradiation position (CIP) of G.A. Siwabessy reactor with neutron flux 1.26 x 1014 neutron s-1cm-2 has been carried out. It was revealed that a radioisotop of gold (198Au) was produced by neutron activation from natural gold. Calculation results showed that 198Au with radioactivity of 0.366 Bq, 2.93 Bq, 9.90 Bq and 23.4 Bq was produced …

Implementation Of Web Cam As Motion Detector With Directshow Interfacing, Yonatan Santoso, Iwan Setiyawan, Victor N. Papilaya

Makara Journal of Technology

Implementation of Web Cam as Motion Detector with DirectShow Interfacing. One of many ways to take control a web cam is by using DirectShow which is integrated in DirectX. DirectShow acts like an API therefore it is easier to use. Afterwards, web cam will be implemented to detect object’s motion as well as camera surveillance. The method is by comparing a reference image with other image which is taken lately. If there are differences between those image it means motion has been detected.

Thermal Stability Of Clay's Galleries In Polypropylene - Clay (Montmorillonite) Nanocomposites Using Polypropylene-Gmaleic Anhydride As Compatibilizer, Sotya Astutiningsih, Pandu Lanang Kinasih, Arief Cahyo Wibowo

Makara Journal of Technology

Thermal Stability of Clay's Galleries in Polypropylene - Clay (montmorillonite) Nanocomposites using Polypropylene-g- Maleic Anhydride as Compatibilizer. Superior properties of food packaging can be achieved using nanocomposite technology. However, fabrication of this materials are complex and expensive. Long term objectives of this research is the synthesis of low cost polypropylene clay nanocomposites (PPCN) via a short-cut method known as ‘cascade engineering’. Cascade engineering principle in PPCN fabrication is performed by using compatibilizer (to enable the mixing of PP and clay) masterbatch, and PPCN in one pot process using melt mixer. This paper present the experimental results using small-angle x-ray diffraction …

Induction And Conduction Electromagnetic Waves Caused By Lightning Strike On The Low Voltage Network, Reynaldo Zoro

Makara Journal of Technology

Induction and Conduction Electromagnetic Waves Caused by Lightning Strike on the Low Voltage Network. Direct and indirect lightning strikes can disturb and induce low voltage overheadlines and it can produced overvoltage due to traveling waves along the lines. This overvoltage can damage the equipments connected to it. It was recorded that there were already a lot of damages of electronic equipments and arrestesr located inside the building of Lightning Measurement Station at Mnt. Tangkuban Perahu. Most of the overvoltage which was developed on the low voltage lines were coming from indirect lightning strike nearby due to the fact that most …

Muara Bekasi – Muara Tawar Offshore Transmission Pipeline Routing And Economic Analysis., Asep Handaya Saputra, Ardiansyah Ardiansyah

Makara Journal of Technology

Muara Bekasi – Muara Tawar Offshore Transmission Pipeline Routing and Economic Analysis. Power plant Muara Tawar will substitute the need of oil fuel to gas as form of economizing and energy conservation. The nearest supply point to fulfill natural gas needed on Muara Bekasi. So that Power Plant Company needed to develop gas pipeline infrastructure to joining the point.The purpose of this study is to create a system of gas transmission pipeline from gas supply point at Muara Bekasi to Power Plant Muara Tawar trough to offshore area. Design of gas transmission pipeline is started with technical data collection and …

Shielding Effectiveness Of Superalloy, Aluminum, And Mumetal Shielding Tapes, Cindy Suit Cheung

Master's Theses

Using MIL-HDBK-419A, MATLAB and Nomographs, Shielding Effectiveness for the Magnetic Field, Electric Field, and Plane Wave were calculated over a frequency range from 10 Hz to 1 GHz. The three shielding tapes used included superalloy, aluminum, and mumetal. Calculations for Shielding Effectiveness involve the computation of Absorption Loss, Reflection Loss, and Re-Reflection Correction Factor. From the outcome of the calculations, it was suitable to conclude that all three metals fulfill the 40 dB Shielding Effectiveness requirements for SGEMP fields for frequencies greater or equal to 1 MHz. Accordingly, all three shielding tapes provide at least 40 dB of shielding to …

Multiscale Modeling Of Impact On Heterogeneous Viscoelastic Solids With Evolving Microcracks, Flavio V. Souza

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Multiscale computational techniques play a major role in solving problems related to viscoelastic composite materials due to the complexities inherent to these materials. In the present work, a numerical procedure for multiscale modeling of impact on heterogeneous viscoelastic solids containing evolving microcracks is proposed in which the (global scale) homogenized viscoelastic incremental constitutive equations have the same form as the local scale viscoelastic incremental constitutive equations, but the homogenized tangent constitutive tensor and the homogenized incremental history dependent stress tensor depend on the amount of damage accumulated at the local scale. Furthermore, the developed technique allows the computation of the …

Carbon Nanotube Membranes For Use In The Transdermal Treatment Of Nicotine Addiction And Opioid Withdrawal Symptoms, Caroline L. Strasinger, Nicole N. Scheff, Ji Wu, Bruce J. Hinds, Audra L. Stinchcomb

Pharmaceutical Sciences Faculty Publications

Transdermal systems are attractive methods of drug administration specifically when treating patients for drug addiction. Current systems however are deficient in therapies that allow variable flux values of drug, such as nicotine for smoking cessation or complex dosing regimens using clonidine when treating opioid withdrawal symptoms. Through the use of functionalized carbon nanotube (CNT) membranes, drug delivery to the skin can be controlled by applying a small electrical bias to create a programmable drug delivery system. Clearly, a transdermal patch system that can be tailored to an individual's needs will increase patient compliance as well as provide much more efficient …

Synthesis Of Magnetic Porous Hollow Silica Nanotubes For Drug Delivery, H. Ma, J. Tarr, M. A. Decoster, J. Mcnamara, D. Caruntu, J. F. Chen, Charles J. O'Connor, Weilie Zhou

Chemistry Faculty Publications

In this paper, we report a synthesis of magnetic porous hollow silica nanotubes (MPHSNTs) using sol-gel method. The MPHSNTs were fabricated by coating Fe(3)O(4) nanoparticles and silica on surfactant hexadecyltrimethylammonium bromide (CTAB) modified CaCO(3) nanoneedles surface under alkaline condition. CaCO(3) nanoneedles and surfactant CTAB are introduced as nanotemplates to form the hollow and porous structures, respectively. After removing CTAB by calcination and etching CaCO(3) nanoneedles away in diluted acetic acid, magnetic porous hollow silica nanotubes with Fe(3)O(4) nanoparticles embedded in the silica shell were achieved. The products were characterized by scanning electron microscopy, transmission electron microscopy, and N(2) adsorption-desorption isotherms. …

Effects Of Contact Load On The Fretting Fatigue Behavior Of In-100 At Elevated Temperature, Alfred G. Traylor Ii

Theses and Dissertations

This thesis studied the effects of contact load of 8006 N on the fretting fatigue behavior of IN-100 at an elevated temperature of 600°C. First, S-N curves were created for a range of applied axial stresses at an identical stress ratio of 0.03 at 8006 N. A condition of partial slip condition necessary to fretting fatigue was verified by generating hysteresis loops, plotting shear force against axial stress. The half-contact width and the crack initiation location were determined for all of the fretting specimens using optical and scanning electron microscopes. The contact widths were consistent with expected analytical values and …

Effects Of Environment On Creep Behavior Of Nextel720/Alumina-Mullite Ceramic Composite With ±45º Fiber Orientation At 1200ºc, Muzaffer Ozer

Theses and Dissertations

The present effort will investigate the off-axis creep behavior of the Nexte720/Alumina-Mullite CMC, a material system which relies on a porous alumina/mullite matrix for damage tolerance as compared to the pure alumina matrix in earlier studies. This research evaluated the creep behavior of N720/AM with a ± 45° fiber orientation at 1200°C in: laboratory air, steam, and argon environments. Creep-rupture tests at the creep stress levels of: 32, 30, 26, and 20 MPa were conducted in each environment. Additionally 35 MPa stress level examined in air and 13 MPa stress level examined both in air and steam. The N720/AM with …

Investigation Of Electrical And Optical Properties Of Bulk Iii-V Ternary Semiconductors, Travis C. Gomez

Theses and Dissertations

Bulk grown III-V ternary semiconductors of In_0.08Ga_0.92Sb and In_0.15Ga_0.85As were investigated through Hall-effect and photoluminescence measurements to determine carrier concentration, mobility, sheet resistivity, and luminescence spectrum. In the past, epitaxial layers of ternary compounds have been grown on binary compound substrates, and thus very limited lattice matched ternary alloys were available. Recently, bulk grown ternary substrates have been developed, and it has presented a renewed interest in using these substrates to grow high quality ternary compounds for use in many next generation optoelectronic devices. The results of photoluminescence (PL) study for the …

Wave Optics Simulation Of Optically Augmented Retroreflections For Monostatic/Bistatic Detection, John J. Tatar Iii

Theses and Dissertations

Optical devices interrogated with a laser in the appropriate band can exhibit strong, deterministic reflections of the incident beam. This characteristic could be exploited for optical target detection and identification. The distribution of reflected power is strongly dependent on the geometry of the interrogation scenario, atmospheric conditions, and the cross section of the target optical device. Previous work on laser interrogation systems in this area has focused on analytic models or testing. To the best of my knowledge, I am presenting for the first time an approach to predict reflected power for a variety of interrogation configurations, targets, and propagation …

Non-Destructive Evaluation Of Aerospace Composites, Jeremy D. Johnson

Theses and Dissertations

Five methods of non-destructive material evaluation (NDE) were used to inspect various forms of damage commonly found in aerospace fiberglass composites: voids, edge and sub-surface delaminations, surface burning, and cracking. The images produced by X-ray, X-ray Computed Tomography, terahertz (THz) imaging, ultrasound, and flash IR thermography were analyzed for the detection of defects. Test results and analysis of each NDE method's capabilities provide a comparison study of conventional techniques versus the emerging technology of THz imaging for the non-destructive evaluation of aerospace composite materials. A comparison guide to the five methods' damage detection effectiveness for fiberglass composites is provided by …