Engineering Commons^™

Cephalometric Analysis Using Magnetic Resonance Imaging, Wade A. Williams

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The purpose of this study was to determine if T1-weighted 3D magnetic resonance images performed at 3.0 Tesla could be used to conduct routine orthodontic cephalometric analysis.

Methods: Three cranial imaging methods were compared using sixteen non-growing subjects (10 male and 6 female) who were not claustrophobic, did not have any metallic restorations on the distal of first molars, had no medical implants and the female subjects were not pregnant. Sagittal cranial images were produced by three methods: (1) a digital lateral cephalometric (LC) radiograph (Orthophos XG Plus, Sirona^TM, Bensheim, Germany), (2) a 12-inch FOV cone beam …

Deep Sea Underwater Robotic Exploration In The Ice-Covered Arctic Ocean With Auvs, Clayton Kunz, Chris Murphy, Richard Camilli, Hanumant Singh, John Bailey, Ryan M. Eustice, Chris Roman, Michael Jakuba, Claire Willis, Taichi Sato, Ko-Ichi Nakamura, Robert A. Sohn

Graduate School of Oceanography Faculty Publications

The Arctic seafloor remains one of the last unexplored areas on Earth. Exploration of this unique environment using standard remotely operated oceanographic tools has been obstructed by the dense Arctic ice cover. In the summer of 2007 the Arctic Gakkel Vents Expedition (AGAVE) was conducted with the express intention of understanding aspects of the marine biology, chemistry and geology associated with hydrothermal venting on the section of the mid-ocean ridge known as the Gakkel Ridge. Unlike previous research expeditions to the Arctic the focus was on high resolution imaging and sampling of the deep seafloor. To accomplish our goals we …

Generating Robust Schedules Subject To Resource And Duration Uncertainties, Na Fu, Hoong Chuin Lau, Fei Xiao

Research Collection School Of Computing and Information Systems

We consider the Resource-Constrained Project Scheduling Problem with minimal and maximal time lags under resource and duration uncertainties. To manage resource uncertainties, we build upon the work of Lambrechts et al 2007 and develop a method to analyze the effect of resource breakdowns on activity durations. We then extend the robust local search framework of Lau et al 2007 with additional considerations on the impact of unexpected resource breakdowns to the project makespan, so that partial order schedules (POS) can absorb both resource and duration uncertainties. Experiments show that our proposed model is capable of addressing the uncertainty of resources, …

A Heuristic Method For Job-Shop Scheduling With An Infinite Wait Buffer: From One-Machine To Multi-Machine Problems, Z. J. Zhao, J. Kim, M. Luo, Hoong Chuin Lau, S. S. Ge

Research Collection School Of Computing and Information Systems

Through empirical comparison of classical job shop problems (JSP) with multi-machine consideration, we find that the objective to minimize the sum of weighted tardiness has a better wait property compared with the objective to minimize the makespan. Further, we test the proposed Iterative Minimization Micro-model (IMM) heuristic method with the mixed integer programming (MIP) solution by CPLEX. For multi-machine problems, the IMM heuristic method is faster and achieves a better solution. Finally, for a large problem instance with 409 jobs and 30 types of machines, IMM-heuristic method is compared with ProModel and we find that the heuristic method is slightly …

Some Rather Mechanical Reflections On Symmetry: In Art, Science, Engineering, Mathematics, Etc., Jim Mcgovern

Articles

This Inaugural Lecture consists of some of my rather mechanical, being an engineer, reflections on symmetry in diverse areas such as art, science, engineering, mathematics, etc. I explain what symmetry is to me, giving examples with lots of images and mentioning or at least barely referencing art, science, architecture, engineering, heritage, cosmology, bicycles, flight, invention, ingenuity, history, wallpaper, mathematics, typography, structures, regular shapes, coordinate systems, spacetime, thermodynamics and suchlike.

Optimal Energy-Delay Routing Protocol With Trust Levels For Wireless Ad Hoc Networks, Eyad Taqieddin, Ann K. Miller, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the Trust Level Routing (TLR) pro- tocol, an extension of the optimized energy-delay rout- ing (OEDR) protocol, focusing on the integrity, reliability and survivability of the wireless network. TLR is similar to OEDR in that they both are link state routing proto- cols that run in a proactive mode and adopt the concept of multi-point relay (MPR) nodes. However, TLR aims at incorporating trust levels into routing by frequently changing the MPR nodes as well as authenticating the source node and contents of control packets. TLR calcu- lates the link costs based on a composite metric (delay …

A Better Nondimensionalization Scheme For Slender Laminar Flows: The Laplacian Operator Scaling Method, Mark M. Weislogel, Yongkang Chen, D. Bolleddula

Mechanical and Materials Engineering Faculty Publications and Presentations

A scaling of the two-dimensional Laplacian operator is demonstrated for certain solutions (at least) to Poisson’s equation. It succeeds by treating the operator as a single geometric scale entity. The belated and rather subtle method provides an efficient assessment of the geometrical dependence of the problem and is preferred when practicable to the hydraulic diameter or term-by-term scaling for slender fully developed laminar flows. The improved accuracy further reduces the reliance of problems on widely varying numerical data or cumbersome theoretical forms and improves the prospects of exact or approximate theoretical analysis. Simple example problems are briefly described that demonstrate …

Electrocatalytic Performance Of Carbon Supported Au-Ir Catalyst As Cathodic Catalyst In Direct Formic Acid Fuel Cell, Wei Chen, Ya-Wen Tang, Tain-Hong Lu

Journal of Electrochemistry

In this paper,it is reported for the first time that the electrocatalytic activities of the carbon supported Au(Au/C),carbon supported Ir(Ir/C) and the carbon supported Au-Ir(Au-Ir/C) catalysts prepared in the aqueous solution with tetrahydrofuran(THF) for the oxidation of formic acid and for the oxygen reduction were compared.It was found that all three catalysts showed no electrocatalytic activity for the oxidation of formic acid,but the electrocatalytic activity of the Au-Ir/C catalyst for oxygen reduction was much better than those of Au/C and Ir/C.Thus,the Au-Ir/C catalyst is suitable to be used as the cathodic catalyst in Direct formic acid fuel cell(DFAFC).

An Hap/Nanosilver Coating Prepared By Electrochemical Deposition And Its Antibacterial Characterization, Zhi-Wang Geng, Hui Wang, Chang-Jian Lin

Journal of Electrochemistry

The silver nanoparticles were prepared by sodium citrate reduction of AgNO₃.The nanoparticles were electrophoretic deposited on titanium, followed by the electrolytic deposition of hydroxyapatite(HAp). It is revealed, by the high-resolution transmission electron microscopy(HRTEM), that the diameters of nanosilver particles ranged from 5nm to 20nm. The XPS and XRD indicated the coating consisting of silver and HAp. According to the SEM images and antibacterial test, it is demonstrated that when the concentrations of the electrophoretic solution became higher more silver particles were depostited, and the antibacterial property improved. However, the particles aggregated on titanium greatly when the concentration exceeded …

Hydrolysis Of Sodium Borohydride By Ru-Ni Foam Catalyst, Jie Cheng, Feng Ye, Tong-Tao Wang, Jing-Jing Li, Yong-Liang Wang, Xin-Dong Wang

Journal of Electrochemistry

This paper presented a method of hydrogen generation from sodium borohydride solution for fuel cells.The Ru-Ni foam catalyst which was prepared by chemical plating showed strong activity and stability.The pretreatment of Ni foam before chemical plating was very important for the catalyst's strong activity and stability.This easy-to-prepared catalyst exhibited a good activity after being used several times.The effects of NaBH₄ concentration,temperature and used times on the hydrogen generation rate were investigated.The results showed that the rate was remarkablely increased with the temperature rising and the rate increased more than ten times when the temperature of reaction rised from 15 …

Preparation And Supercapacitive Properties Of Co(Oh)2/Nay Composite, Chi Ma, Ling-Bin Kong, Yong-Chun Luo, Long Kang

Journal of Electrochemistry

The Co(OH)₂/NaY composite was prepared by chemical precipitation method and then tested as an active electrode material for an electrochemical supercapacitor.The results indicated that the composite displayed superior capacitive performance.The maximum specific capacitance of Co(OH)₂ was 632.5 F/g.The structure and electrochemical properties of the composite were also discussed.

Corrosion Inhibition Of Self-Assembled Films On Iron By Electrochemical Impedance Spectroscopy, Yuan-Yuan Feng, Shen-Hao Chen, Juan-Juan Zhou, Wen-Juan Guo

Journal of Electrochemistry

The self-assembled films of tetradecylamine were formed on iron surface, and the inhibition ability of which for iron corrosion in 0.5 mol/L H₂SO₄ solutions was studied by electrochemical impedance spectroscopy technique. Results indicated that longer immersion time would result in stronger inhibition ability of the films. The maximal inhibition efficiency(IE) of the tetradecylamine films was 68.7%. When the tetradecylamine films were modified by dodecylthiol, the mixed films became denser and more stable, thus the inhibition ability increased remarkably. The η of the mixed films increased to 78.2%.

Preliminary Study Of Single Flow Zinc-Nickel Battery, Li Zhang, Jie Cheng, Yu-Sheng Yang, Yue-Hua Wen, Xin-Dong Wang, Zi-Li Xie

Journal of Electrochemistry

The micromorphology of zinc electrodeposited at different currents in the flowing electrolyte was studied.It has been shown that the structure of the zinc became compacted with the increase of the charge current density and no zinc dendrite was presenct.A cell with 2Ah capacity was assembled and the charge-discharge test was performed.The results showed that the average charge voltage was 1.84V and the average discharge voltage was 1.65V.The high efficiencies can be achieved with an average coulombic efficiency of 97% and energy efficiency of 86% over 1000 cycles.

Electrochemical Reductive Behaviors Of 3,4,5,6-Tetrachloro-2-Trichloromethylpyridine At Ag Electrode, Chun-An Ma, Yi-Jiao Hu, Ying-Hua Xu

Journal of Electrochemistry

The electrochemical reductive behavior of 3,4,5,6-tetrachloro-2-trichloropyridine(heptachloropyridine) on silver electrode in the mixture of acetonitrile and water solutions containing TBAP was investigated by cyclic voltammetry.The influences of scan rate,concentration and temperature on the electrochemical behavior were discussed.It was shown that the reduction of heptachloropyridine on the silver electrode was a diffusion-controlled irreversible process.The diffusion coefficient of heptachloropyridine in the acetonitrile solution was 3.0×10^-5 cm²/s.The mechanism of the dechloration of 3,4,5,6-tetrachloro-2-trichloropyridine was also discussed.

Direct Electrochemistry Of Hemoglobin On The Electrode Modified With Ddab And Swcnt, Wen-Jing Hou, Lin Zhou, Xia-Qin Wu, Hong-Xia Zhang, Wen Xie, Liu Yang, Zhong-Qing Lu

Journal of Electrochemistry

Hemoglobin(Hb) was immobilized onto the surface of glassy carbon electrode with the single-wall carbon nanotubes and surfactant didodecyldimethylamonium bromide(DDAB) modified previously and its electrochemical behaviors have been investigated by cyclic voltammetry.A pair of well-defined redox peaks has been obtained.Cyclic voltammetry and electrochemical impedance spectroscopy(EIS) were also used to study on the effect of different concentration of SWCNT in DDAB.The result shows that the 1 mg/mL is the best choice.The dependence of E₀' on solution pH with the slope of 39 mV/pH,indicated that redox of the Hb is a one electron reaction with two protons transfer.The results also showed …

The Effect Of Ru: Sn On Properties Of Ru-Ir-Sn Oxide Anode Coatings, Lei Ji, Jun-Tao Wang, Wen-Bin Liu, Li-Kun Xu, Gui-Lin Xue

Journal of Electrochemistry

The anode coatings of Ru-Ir-Sn oxide with different Ru/Sn ratios were prepared by sol-gel method.The influences of Ru/Sn ratio on properties of anode coatings were studied by scanning electron microscope(SEM),energy dispersive X-ray detector(EDX),X-ray diffraction(XRD).The potential of chlorine evolution,current efficiency,accelerated life,cyclic vohammetry and electrochemical impedance spectroscopy(EIS) tests were carried out.The results showed that there was an obvious effect of Ru/Sn ratio on the morphology of the coatings.The cyclic voltammogram,double layer capacitances and accelerated life of anode coatings had a tendency to fall down firstly then increased as the Ru% increased,the current effency and potential of chlorine evolution had a tendency to …

Design And Fabrication Of The High Efficient Platinum-Nanoporous Gold Catalysts, Zhao-Na Liu, Jin-Tao Zhang, Fang Tian, Peng-Peng Liu, Hou-Yi Ma, Yi Ding

Journal of Electrochemistry

The nanoporous gold(NPG) electrodes with uniform pore sizes and ligaments were prepared by using a simple dealloying method.The as-prepared NPG showed high catalytic activity towards the oxidation of formic acid and formaldehyde.After tiny amount of platinum was deposited onto the NPG substrate,not only the structure stability of NPG was greatly improved,but also the Pt-Au bimetallic catalysts displayed the better catalytic activity and the stronger poison resistance towards the electrooxidation of small organic molecules than the bulk platinum due to synergistic effect between Au and Pt compositions.

Study On Electrocatalytic Oxidation Of Salbutamol At Carbon Nanotubes Modified Electrode, Ying-Liang Wei, Lu-Ping Zhang, Chen Shao, Hui Feng, Xian-Li Li

Journal of Electrochemistry

The multi-wall carbon nanotubes(MWNT) were dispersed successfully into water in the presence of dihexadecyl hydrogen phosphate(DHP) and a stable well-distributed suspension.A was formed sensor based on the multi-carbon nanotubes film coated glassy carbon electrode was developed.The electrochemical response of salbutamol was studied by square wave voltammetry.The oxidation peak potential of salbutamol at the modified electrode was observed at 0.604 V,which shifted about 40 mV negatively.The peak current increased 4.5 folds,in contrast to that at a bare electrode.Under optimal measurement conditions,there was a good linear relationship between the peak current(Ipa) and salbutamol concentration(C) in the range from 8.3 × 1 0 …

Formation Of Copper Microcrystals On Porous Silicon Films, Lan-Li Chen, Fu-Fang Zhou, Bao-Gai Zhai, Yuan-Ming Huang

Journal of Electrochemistry

Microcrystals of metallic copper were electrochemically deposited onto the surface of porous silicon films in the aqueous electrolyte of copper(II) chloride.The microstructures of electrochemically deposited copper microcrystals on the porous silicon films were characterized by using scanning electron microscopy.The results have demonstrated that both center-hollowed and center-solid equilateral triangles in the sizes of several micrometers can be formed on the smooth bed of copper microcrystals.As the deposition duration increased from 0 to 28 hours,the fractal dimensions of the porous silicon was decreased from 2.608 to 2.252,suggesting that the electrochemical deposition can smooth the rough surface of porous silicon films.Compared to …

A Study Of Pd-Ir On Nickel Foam Cathode For Aluminum-Hydrogen Peroxide Semi-Fuel Cells, Ding-Wang Zhu, Dan-Dan Chen, Bi-Jin Li, Gui-Ling Wang, Dian-Xue Cao

Journal of Electrochemistry

The Pd-Ir/Ni electrodes were prepared by electrodeposition of Pd and Ir on the porous nickel foam surface.The structure,composition and state of the Pd-Ir catalyst were analyzed using SEM and XPS.The catalytic performance of Pd-Ir/Ni for H₂O₂ electroveduction at different concentrations of H₂O₂ were investigated.A limiting current density of 318 mA/cm² was obtained with 0.4 mol/L H₂O₂.The aluminum-hydrogen peroxide semi-fuel cells using different aluminum alloys as anode and Pd-Ir/Ni as cathode were assembled and tested.It was found that the fuel cell with aluminum-manganese alloy anode demonstrated a maximum power density …

Electrocatalytic Oxidation Of Salicylic Acid At Novel Gold Nanoparticle-Modified Glassy Carbon Electrode, Yan-Ping Cui, Chang-Zhu Yang, Jian Huang, Wen-Hong Pu, Jing-Dong Zhang

Journal of Electrochemistry

A gold nano-particles modified glassy carbon electrode(GNP/GCE) was prepared by the"seed-mediated gold nano-particles growth method".Field emission scanning electron microscopy,ultraviolet-visible(UV-vis) spectroscopy analysis and electroalaylsis were employed to study the morphology and electrochemical performances.The resulting electrode showed excellent electro-catalytic activity toward the oxidation of salicylic acid and the response sensitivity was 1.8 fold than that obtained on GCE.Good linear relationship was obtained between response current and salicylic acid concentration in the range of 5.0 × 10^-7 ~8.0 × 10^-5 mol/L,which could be used in the detection of trace salicylic acid.

Direct Electrochemistry Of Hemoglobin Immobilized On The Electrode Modified With Ionic Liquid And Kgm, Liu Yang, Xia-Qin Wu, Wen-Jing Hou, Lin-Fei Gu, Rong Wang, Xiao-Ming Guo, Zong-Rang Zhang

Journal of Electrochemistry

Hemoglobin(Hb) has been immobilized on a glassy carbon electrode(GCE) surface with konjac glucomannan(KGM) and room temperature ionic liquid(RTIL).And which electrochemical behaviors have been investigated by cyclic voltammetry.The results shown that the entrapped Hemoglobin undergoes fast direct electron transfer reactions with formal potential of-0.38V(vs.SCE) and the E0' is linearly dependent on solution pH with a slope value of 51 mV/pH,due to the electron transfer of HbFe³⁺/HbFe²⁺ redox couple companied with a proton transfer.The electrocatalytic reduction of oxygen was also explored at the Hb-KGM/RTIL/Nafion/ GC electrode.

Performance Of Magnetic Field Coupled With Electrochemical Process For Preparing Polyaluminum Chloride, Ke-Wu Pi, Wen-Qi Gong, Zheng-Qing Huang

Journal of Electrochemistry

Polyaluminum chloride(PAC) was prepared by electrochemical process coupled with magnetic field paralleling to the gravitation direction.The electrolyte of 0.1 M AlCl3 solution was used,with the iron plates as cathode and aluminum sheets as anode.PAC of 0.6 M total aluminum(AlT),83.2% Alb to AlT and basicity(Ba)=2.4 was synthesized when magnetic flux density was 0.4T,the distance of electrodes was 15 mm,the voltage of electrolysis cell was 2.4 V and current density was 300 A/m2.Under above experimental conditions,the voltage efficiency,energy efficiency and electrodes surface area to reduction cells of electrochemical reactor were 85.2%,81.5% and 140.1m2/m3,respectively.The polarization curves determined by constant-current method showed that the …

Study Of Triethyl Phosphate Self-Assembled Films On Iron For Corrosion Inhibition, Wen-Juan Guo, Shen-Hao Chen, Wei He, Xue-Hui Pang, Yuan-Yuan Feng

Journal of Electrochemistry

The self-assembled film of triethyl phosphate(TEP) formed on the iron surface was found to protect iron from corrosion in 0.5 mol·L^-1 H₂SO₄ efficiently. The inhibition effects were investigated using the electrochemical impedance spectroscopy(EIS).EIS demonstrated that the charge-transfer resistance of the electrode covered with TEP film was greater than that of the naked iron electrodes and the inhibition efficiency of TEP film increased quickly in the initial period and then increased slowly. Quantum chemical calculations provide information about the process of adsorption of molecules on the metal surface at the molecular level.

Electrochemical Synthesis, Characterization And Fluorescence Property Of Nano Na2Sif6, Guo-Xu Qin, Xin-Jun Wan, Xi-Mei Yuan, Dao-Bao Chu

Journal of Electrochemistry

The nano TiO₂ film was prepared by sol-gel process and characterized with X-ray diffraction(XRD) and scanning electron microscope(SEM).It was found that the average size of pore diameter was about 80 nm for the nano TiO₂ film.The Nano Na₂SiF₆ was synthesized by electrochemical deposition on the nanoporous film electrode and characterized with XRD and transmission electron microscope(TEM).The result showed that the average size of nanoparticle was 20 nm for the nano Na₂SiF₆.The fluorescence property of nano Na₂SiF₆ was also studied briefly.The result indicated that the nano Na₂SiF …

Electricity Generation In Microbial Fuel Cells Catalyzed By Mixed Culture And Pure Culture, Chen-Dong Shuang, En-Ren Zhang, Guo-Wang Diao, Fang-Fang Fan, Jie Yuan

Journal of Electrochemistry

Microbial fuel cells(MFCs) were constructed by inoculating fresh sedimentary microorganisms.Effect of phenol on performance of MFCs was investigated.The results showed that the generation of electrical current was induced by bacteria attached on the surface of the anode.Presence of phenol reduced the rate of glucose consumption and extended the duration of electricity generation with the same addition of glucose.In addition,the electricity generation by a single strain(belonging to pseudomonas species) separated from the sedimentary MFC was also investigated.The experimental results indicated that the presence of metabolic intermediates which exhibited electrochemical activity was necessary for the electricity production.Analysis of GC-MS showed that the …

Spatially Resolved Optical Absorption Spectrometry And Single Crystal Diffraction On Metamict Materials, Alison Savage, Oliver Tschauner, Sergey Tkachev

Undergraduate Research Opportunities Program (UROP)

A major goal in developing storage medium for radioactive waste is the identification of chemically suitable and durable material for storage in repositories (Lumpkin 2006). Radiation damage induces enhanced chemical diffusion and structural breakdown of the host materials, which can lead to contamination of the surrounding environment. During this project four different naturally occurring materials which are common carriers of thorium and uranium were examined : gadolinite, perrierite, allanite, and pyrochlore of which the first three are silicates and pyrochlore being an oxide. Their spectra and absorptions bands were examined to identify prominent features due to radiation damage. The goal …

Computational Studies Of H2, O2, And Co Adsorption On Pt And Pt-Ru Catalyst Clusters For Hydrogen Fuel Cell Applications, Huy Mai, T.J. Dhilip Kumar, P. Tarakeshwar, Naduvalath Balakrishnan

Undergraduate Research Opportunities Program (UROP)

Previous computational studies of hydrogen fuel cell catalysis primarily focus on single adsorbate and therefore do not reflect the realistic situation. Here we investigated the effect of multiple hydrogen, oxygen, and carbon monoxide adsorption on bimetallic nanoclusters as allowed by computational resources. The criteria of which we studied were adsorption energies, electron densities, electrostatic charges, and HOMO-LUMO energy gaps with respect to each structure. We found that Pt-Ru clusters have better performance than pure Pt clusters early in the adsorption course, and pure Pt clusters are more consistent than Pt-Ru clusters in a sequence of adsorbate introduction.

Raman Studies Of 1,3,5,7 Cyclooctatetraene At High Pressure, Martin Galley, Ed Romano, Sergey Tkachev, Michael Pravica

Undergraduate Research Opportunities Program (UROP)

We performed Raman spectroscopic studies of 1,3,5,7-cyclooctatetraene at elevated pressures up to 10 GPa with the aim of examining possible planarization of the molecule and further studying two prior-discovered phases of the solid with pressure. The Raman excitation source was a Krypton-ion laser operating at 674.1 nm (give wavelength).

1,3,5,7 Cyclooctatetraene has an octagonal formation however it is not aromatic or anti-aromatic (not a subject to the 4n+2 Huckel’s rule) [1]. As a result, its adopts a somewhat reactive tub shape. Upon the addition or removal of one to two electrons under ambient conditions, the molecule planarizes and becomes aromatic …

Structural Studies Of Crsi2 At High Pressures And Temperatures, Weldu Gabrimicael, Ravhi S. Kumar, Andrew Cornelius

Undergraduate Research Opportunities Program (UROP)

It is of extreme importance to develop new potential energy sources to reduce dependence on fossil fuels. As a result of this, the study of thermoelectric materials, capable of changing heat into electrical energy, has become a field of great interest regarding fundamental properties. To help better understand these materials, facilities for the measurement of relevant properties at high pressure have been developed, but lack the ability to characterize the materials at high temperature and pressure. Therefore, this project has the goal of developing a heater arrangement to be used in conjunction with the high pressure capabilities already developed to …