Engineering Commons^™

Optical Properties Of Gallium-Doped Zinc Oxide-A Low-Loss Plasmonic Material: First-Principles Theory And Experiment, Jongbum Kim, Gururaj V. Naik, Alexander V. Gavrilenko, Krishnaveni Dondapati, Vladimir I. Gavrilenko, S. M. Prokes, O. J. Glembocki, V. M. Shalaev, Alexandra Boltasseva

Birck and NCN Publications

Searching for better materials for plasmonic and metamaterial applications is an inverse design problem where theoretical studies are necessary. Using basic models of impurity doping in semiconductors, transparent conducting oxides (TCOs) are identified as low-loss plasmonic materials in the near-infrared wavelength range. A more sophisticated theoretical study would help not only to improve the properties of TCOs but also to design further lower-loss materials. In this study, optical functions of one such TCO, gallium-doped zinc oxide (GZO), are studied both experimentally and by first-principles density-functional calculations. Pulsed-laser-deposited GZO films are studied by the x-ray diffraction and generalized spectroscopic ellipsometry. Theoretical …

Thermolysis And Kinetics Of Scrap Tyre And Bagasse For Energy Utilization, Petro Ndalila

Tanzania Journal of Engineering and Technology (TJET)

The increase of energy demand has brought concern to find alternative fuel that will at least sustain the requirement. Bagasse and scrap tyre are waste generated in our industrial activities, which can be used in energy production to subsidize the demand. This paper, aim to study the decomposition behaviour and kinetics of biomass (bagasse) and scrap tyre as preliminary stage of fuel sample analysis to be considered for energy production in gasification/combustion or pyrolysis facilities. The behaviour demonstrated with thermogravimetric analyzer (TGA), shows that all samples have high volatile amount release, 84.21% for bagasse and 85.08% for scrap tyre, which …

Optimising The Performance Of Roundabouts In Dar Es Salaam City, David Mfinanga

Tanzania Journal of Engineering and Technology (TJET)

Intersections are one of the major bottlenecks that aggravate congestion in road networks; effective control of which is an important strategy in improving traffic flow. While developing countries have found it hard to adopt sophisticated means of intersection control, they have also not optimised the performance of roundabouts. This paper reviews the performance of roundabouts, which have become increasingly popular in recent years, as simple and low cost forms of intersection control. The performance of three major roundabouts in Dar es Salaam has been analysed and results show that roundabouts can accommodate high traffic volumes without causing excessive delays. The …

Analysis Of Factors Affecting Technological Innovativeness In Engineering Enterprises In Tanzania, Emanuel Mjema

Tanzania Journal of Engineering and Technology (TJET)

This paper discusses the technological innovativeness in engineering enterprises in Tanzania and analyses the factors affecting the innovativeness. It starts by analyzing various concepts regarding innovation, then analyzed from documentary review factors affecting innovativeness and then analyzed the innovativeness in Tanzanian enterprises. From the documentary review it was learnt that the following key factors influence technological innovativeness: Existence of innovation management; Existence of market to absorb the products of innovation; Existence of partnership between the universities and the firms; Existence of positive culture and politics towards innovation; The government playing its role to influence innovation; Existence of the right knowledge; …

The Marine Electronic Highway And Routeing Scheme Along The West Coast Of India And Sri Lanka : Feasibility Study : "Aiming Towards A Sustainable Maritime Transportation System", Sellakkannu I. Abul Kalam Azad

World Maritime University Dissertations

No abstract provided.

Analysis Of Onshore Wind - Solar Pv - Battery Bank Power Generation System Development For Toamasina Port, Hary Lys Jean Louis Soloniainanirinanandrianina

World Maritime University Dissertations

No abstract provided.

Cost And Benefit Analysis Of Shore Side Electricity In The Port Of Tanjung Perak, Indonesia, Oscar Yogi Yustiano

World Maritime University Dissertations

No abstract provided.

Using Software-Based Decision Procedures To Control Instruction-Level Execution, William B. Kimball

AFIT Patents

An apparatus, method and program product are provided for securing a computer system. A digital signature of an application is checked, which is loaded into a memory of the computer system configured to contain memory pages. In response to finding a valid digital signature, memory pages containing instructions of the application are set as executable and memory pages other than those containing instructions of the application are set as non-executable. Instructions in executable memory pages are executed. Instructions in non-executable memory pages are prevented from being executed. A page fault is generated in response to an attempt to execute an …

Numerical Modeling Of Infrared Thermography Techniques Via Ansys, Hayder Abdulnabi Thajeel

Masters Theses

"Several inspection techniques have been developed over years. Recently, infrared thermography (IRT) technology has become a widely accepted as a nondestructive inspection (NDI) technique for different fields and various applications as well. Infrared thermography stands as one of the most an attractive and a successful NDI technique that has ability to detect the object's surface/subsurface defects remotely based on observing and measuring the surface's emitted infrared heat radiation by using an infrared camera. The finite element modeling FEM ANSYS was successfully used for the modelling of several IRT techniques; such as Pulsed Thermography (PT) and Lock-in Thermography (LT) that can …

Enhanced Optical Bistability With Film-Coupled Plasmonic Nanocubes, Christos Argyropoulos, Cristian Ciraci, David R. Smith

Department of Electrical and Computer Engineering: Faculty Publications

Colloidally synthesized nanocubes strongly coupled to conducting films hold great promise for enhancing different nonlinear optical processes. They exhibit a robust and sensitive scattering response that can be easily controlled by their geometrical and material parameters. Strong local field enhancement is generated at the gap regions between the nanocubes and the metallic film. We show that strong optical bistability and all-optical switching behavior can be obtained by loading these nanogaps with Kerr nonlinear materials. Relatively low input intensities are required to obtain these nonlinear effects. The proposed design can lead to efficient, low-power, and ultrafast all-optical memories and scattering nanoswitches.

Analysis Of Power Efficiency Of A Direct-Driven Locally Fabricated Permanent Magnet Ac Generator For Small-Scale Wind Power Applications In Tanzania, Mussa Iddi Mgwatu Dr.

Tanzania Journal of Engineering and Technology (TJET)

The use of direct-driven permanent magnet alternating current (AC) generators offers the opportunity to reduced costs and increased system efficiency. This type of generator could be the best alternative for rural population whom are not connected to the national grid. To improve the design and efficiency of locally fabricated generators, it is imperative to characterize both their mechanical and electrical parameters. This paper presents the analysis of power efficiency of the synchronous permanent AC generator locally fabricated in Tanzania. In this case, load resistance and rotational speed are characterized using designed experiment. The output current and voltage of the generator …

A Cost/Benefit Evaluation Of Incentives Paid For Asphalt Concrete Hot Mix (Achm) Properties, Christopher T. Mckenney

Theses and Dissertations

The purpose of this study was establishing if projects receiving incentive payments for Asphalt Concrete Hot Mix (ACHM) properties were providing a better quality and longer pavement life cycle. Reviewing governmental agencies' and states' Department of Transportation (DOT) standards, through literary review, indicated other possible guidelines and recommendations. Results were formulated by employing a specific methodology, allowing for data validation through an ordered series of groupings and project pairings. Arkansas Highway and Transportation Department (AHTD) databases furnished essential pavement data to accomplish this task. Derived from methodology, data analysis supported the comparison analysis of selected construction projects. Documented conclusions validated …

Localized Corrosion Behavior Of Sensitized 304 Stainless Steel By Scanning Reference Electrode Technique, Chen-Qing Ye, Rong-Gang Hu, Rui-Qing Hou, Xiao-Ping Wang, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Based on a home-built setup of scanning reference electrode technique, and combined with conventional electrochemical measurements, the localized corrosion behavior of sensitized 304 stainless steel (304ss) had been investigated in this work. The results showed that, the non-sensitized 304ss or 304ss sensitized at 550 oC was susceptible to pitting; while 304ss sensitized at 650 oC or 750 oC suffered severe intergranular corrosion in 10% FeCl3 solution.

Application Of Synchrotron Radiation Based Electrochemical In-Situ Techniques To Study Of Electrode Materials For Lithium-Ion Batteries, Zheng-Liang Gong, Wei Zhang, Dong-Ping Lv, Xiao-Gang Hao, Wen Wen, Zheng Jiang, Yong Yang

Journal of Electrochemistry

Due to its merits of high brightness and high intensity, high level of polarization and wide tunability in energy, etc., synchrotron radiation technique provides an unique platform for analysis of the relationship among composition–structure–performance of materials for lithium ion batteries, especially for in-situ, real time dynamic investigation of the electrochemical reaction mechanism, aging process and failure mechanism during charge-discharge cycling. In this paper, we review the latest developments in application of synchrotron based electrochemical in-situ experimental methods to studies of lithium ion batteries. The paper mainly focuses on the application of electrochemical in-siu XRD and XAFS techniques to the investigations …

Controllable Synthesis Of Dispersed Spherical Fe3O4 Nanoparticles As Lithium-Inserted Materials, Hong-Li Zou, Wei-Shan Li

Journal of Electrochemistry

Dispersed spherical Fe₃O₄ nanoparticles were synthesized by a hydrothermal method. The influences of odecyl trimethyl ammonium bromide (DTAB) concentration on the morphology and particle size of the as-prepared Fe₃O₄ were studied. Electrochemical performance of the as-prepared sample as anode materials of lithium ion battery was investigated. It is found that the as-prepared sample exhibits superior rate performance and cycle performance. The nano-sized materials provide structural stability and favor the transfer of lithium ions.

Study On Hydrogen Bubble Template Fabrication Of Porous Biomaterials Coatings By Electrochemically Induced Deposition, Hui Wang, Chang-Jian Lin, Ren Hu, Ke-Qin Zhang, Hong-Ping Duan, Xiang Dong

Journal of Electrochemistry

So far, the pore architecture in biomaterials plays a critical role on the cell response and integration between the biomaterials and implanted environment. In this study, porous calcium phosphate (CaP) coatings and CaP/protein composite coatings have been successfully constructed on titanium substrate by using an electrochemically induced deposition technique. The shape, size and pliability of CaP crystals are controlled by electrolyte concentration, temperature, current density, time and protein additive in preparing process. In addition, the formation mechanism of the porous structure is discussed based on the “hydrogen bubble template” model. It demonstrates that the growth velocity of CaP crystals should …

An Investigation On The Solid Electrolyte Interphase Of Silicon Anode For Li-Ion Batteries Through Force Curve Method, Jie-Yun Zheng, Hao Zheng, Rui Wang, Hong Li, Li-Quan Chen

Journal of Electrochemistry

Non-aqueous electrolyte has been widely used in commercial Li-ion batteries. Optimized choices are proceeding among the various types of salts and solvents in an effort to achieve higher performance of electrolyte. However, the electrolyte will be reduced in low potential and the reductive product will be deposited on the surface of anode to form a passivating layer, solid electrolyte interphase (SEI). Herein an atomic force microscopy (AFM) based method was introduced to study the structure and mechanical property of SEI on silicon thin film anode during the first cycle. Silicon has been known as the most potential candidate anode for …

Preparation And Electrochemical Properties Of Flake-Like Liv3O8 By Soft Template Assisted Sol-Gel Method As Anode Material For Aqueous Li-Ion Battery, Shuai Tan, Dan Sun, Hai-Yan Wang, Tian-Li Hou, Zhong-Xing Xiao, You-Gen Tang

Journal of Electrochemistry

Composite electrode of CuF₂/MoO₃/C was fabricated through high energy mechanical milling. The properties of CuF₂/MoO₃/C were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (TEM), galvanostatic charge-discharge measurements, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the grain sizes of CuF₂ and MoO₃ after milling were 200 ~ 300 nm, and the initial discharge capacity of CuF₂/MoO₃/C was 647 mAh·g^-1 at room temperature and at a current density of 10 mAh·g^-1. However, the …

Synthesis And Electrochemical Performance Of Nano Licopo4 By Polyol Method, Fei Wang, Yang Jun

Journal of Electrochemistry

High potential LiCoPO₄ cathode material was synthesized by polyol method. Carbon layer of ca. 3 nm thick was coated on the LiCoPO₄ surfaces by chemical vapor deposition from methylbenzene. Crystalline structure, morphology and electrochemical performance of the sample were studied by XRD, SEM, TEM, CV and galvanostatic charge/discharge curve. The synthesized material via polyol method showed a pure phase of LiCoPO₄. The LiCoPO₄/C electrode delivered a high discharge capacity of 132 mAh·g^-1 and maintained 78% of the initial capacity after 50 cycles at 0.1C rate. The two-step extraction/insertion behavior of Li⁺ in …

Electrochemical Na-Storage Materials And Their Applications For Na-Ion Batteries, Jiang-Feng Qian, Xue-Ping Gao, Han-Xi Yang

Journal of Electrochemistry

Oncoming large scale electric energy storage (EES) requires battery systems not only to have sufficient storage capacity but also to be cost-effective and environmentally friendly. Li-ion batteries for widespread EES applications may be limited due to the constraint of global lithium resource. From the considerations of available resources and environmental impact, Na-ion batteries have potential advantages as next generation secondary batteries and an alternative to Li-ion batteries. However, in the present state of the art, the Na-storage cathodes reported so far are still deficient both in energy density and power capability, while the carbon and alloy anodes for Na-ion batteries …

Cmk-3/Sulfur Composite (CXSY) And Room-Temperature Na/S Battery, Qing Zhao, Yu-Xiang Hu, Kai Zhang, Li-Jiang Wang, Zhan-Liang Tao, Jun Chen

Journal of Electrochemistry

A series of ordered mesoporous carbon (CMK-3)/sulfur composite (C_xS_y) with different sulfur contents were synthesized via a melt-diffusion method. XRD, Raman, BET, SEM, and TEM techniques were used to characterize the structure and morphology of the as-prepared composite. The electrochemical performance of CMK-3/sulfur composite as the electrode of Na/S battery was tested at room temperature. Cyclic voltammograms show that one obvious reduction peak was located at about 1.61V, which is corresponding to the formation of Na₂S_x (x=2~5), while two oxidation peaks were displayed at about 1.82V and 1.95V, which are belonging to the …

Preparation Of The Particle Size Controllable Lifepo4/C And Its Electrochemical Profile Characterization, Ming-E Wang, Jing-Yuan Liu, Meng-Yan Hou, Yong-Yao Xia

Journal of Electrochemistry

We adopted an effective route to prepare the particle size controllable core-shell structure carbon-coated LiFePO₄ from different sized FePO₄ precursors, varying from 80 nm, 200 nm and 1 μm by an in situ polymerization method integrated with a surface modification technology. The discharge capacities of the three sized LiFePO₄/C are, respectively, 162 mAh·g^-1, 142 mAh·g^-1 and 92 mAh·g^-1 at 0.1C rate. The nano-sized LiFePO₄-a/C (80 nm) delivers a discharge capacity as large as 100 mAh·g^-1 even at 30C, while the macroscopic LiFePO₄-c/C (1 μm) exhibits a much …

Surface Composition Structure And Electrochemical Performance Of Aluminum Doped Lifepo4, Huai-Fang Shang, Wei-Feng Huang, Wang-Sheng Hu, Ding-Guo Xia, Zi-Yu Wu

Journal of Electrochemistry

Despite there are many successful reports about the preparation of electrode materials with surface coating for lithium ion batteries, the study in surface self-coating of cathode materials using segregation of doping elements and their electrochemical properties is still very rare. The LiFePO₄ particles with rich-Al on the surface were synthesized by one step solvothermal route. TEM results demonstrated that the surface of the obtained LiFePO₄ particles was well-covered by the amorphous coating. The soft X-ray absorption spectroscopy (XAS) and Auger electron spectroscopy (AES) component analyses revealed that the amorphous coating was composed of LiFe_1-xAl_xPO …

Preparation And Electrochemical Properties Of Amorphous Znsno3/C By Hydrothermally Carbonization Method, Guo-Qing Fang, Rui-Xue Zhang, Wei-Wei Liu, Bing-Bo Xia, Hong-Dan Sun, Hai-Bo Wang, Jing-Jing Wu, Shinko Kaneko, De-Cheng Li

Journal of Electrochemistry

The amorphous ZnSnO₃@C composite was synthesized via a simple glucose hydrothermal and subsequent carbonization approach. The structure, morphology and electrochemical property of the composite were characterized by XRD, TEM and electrochemical measurements. Compared to bare ZnSnO₃, the ZnSnO₃/C composite exhibited markedly enhanced lithium storage property and cycle performance, delivering a reversible capacity of 659 mAh·g^-1 after 100 cycles at a current density of 100 mA·g^-1.

Synthesis And Electrochemical Property Of Li2Fesio4/C Cathode Material By Solid State Method, Jiao-Li Sun, Zhi-Jiao Chen, Yi-Xiao Li, Hu Cheng

Journal of Electrochemistry

Li₂FeSiO₄/C cathode material was synthesized using Li₂SiO₃ and FeC₂O₄ as raw materials by solid state method. The structure and morphology of the material were characterized by XRD and SEM. The electrochemical properties of the material were studied by constant-current cyclic testing. The results show that Li₂FeSiO₄/C has a good electrochemical performance. The first discharge capacity of Li₂FeSiO₄/C cathode material at 30oC reached 167 mAh∙g^-1 when cycled at 10 mA∙g^-1 between 1.5 and 4.8 V.

Aqueous Solution-Evaporation Route Synthesis And Phase Structural Research Of The Li-Rich Cathode Li1.23Ni0.09Co0.12Mn0.56O2 By In-Situ Xrd, Chong-Heng Shen, Shou-Yu Shen, Zhou Lin, Xiao-Mei Zheng, Hang Su, Ling Huang, Jun-Tao Li, Shi-Gang Sun

Journal of Electrochemistry

The Li-rich Li_1.23Ni_0.09Co_0.12Mn_0.56O₂ material was synthesized via aqueous solution-evaporation route. The structure and morphology of the material were characterized by means of XRD and SEM. The results indicated that the single particle of the product was polygonal with the size of 330 nm and the structure was layered solid solution with a certain amount of Li₂MnO₃. Electrochemical tests showed that the first discharge capacity of the Li-rich layered material was 250.8 mAh·g^-1 at 0.1C, the capacity retention was 86.5% after 40 cycles. Through in-situ XRD study …

Mems Cantilever Sensor For Thz Photoacoustic Chemical Sensing And Spectroscopy, Nathan E. Glauvitz

Theses and Dissertations

Sensitive Microelectromechanical System (MEMS) cantilever designs were modeled, fabricated, and tested to measure the photoacoustic (PA) response of gasses to terahertz (THz) radiation. Surface and bulk micromachining technologies were employed to create the extremely sensitive devices that could detect very small changes in pressure. Fabricated devices were then tested in a custom made THz PA vacuum test chamber where the cantilever deflections caused by the photoacoustic effect were measured with a laser interferometer and iris beam clipped methods. The sensitive cantilever designs achieved a normalized noise equivalent absorption coefficient of 2.83x10^-10 cm^-1 W Hz^-1/2 using a 25 …

Systems Metabolic Engineering Of Microbial Cell Factories For The Synthesis Of Value-Added Chemicals, Arul Mozhy Varman

All Theses and Dissertations (ETDs)

Microbial cell factories offer us an excellent opportunity for the conversion of many different cheaply available raw materials into valuable chemicals. Systems metabolic engineering aims at developing rational strategies for the engineering of microbial hosts by providing global level information of a cell. This dissertation focuses on metabolic engineering, bioprocess modeling and pathway analysis, to develop robust microbial cell factories for the synthesis of value-added chemicals. The following research tasks were completed in this regard.

First, statistical models were developed for the prediction of product yields in engineered microbial cell factories - Saccharomyces cerevisiae and Escherichia coli: Chapter 2). A …

3d Conductive Nanocomposite Scaffold For Bone Tissue Engineering, Aref Shahini, Mostafa Yazdimamaghani, Kenneth J. Walker, Margaret A. Eastman, Hamed Hatami-Marbini, Brenda J. Smith, John L. Ricci, Sundar V. Madihally, Daryoosh Vashaee, Lobat Tayebi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Bone healing can be significantly expedited by applying electrical stimuli in the injured region. Therefore, a three-dimensional (3D) ceramic conductive tissue engineering scaffold for large bone defects that can locally deliver the electrical stimuli is highly desired. In the present study, 3D conductive scaffolds were prepared by employing a biocompatible conductive polymer, ie, poly(3,4-ethylenedioxythiophene) poly (4-styrene sulfonate) (PEDOT:PSS), in the optimized nanocomposite of gelatin and bioactive glass. For in vitro analysis, adult human mesenchymal stem cells were seeded in the scaffolds. Material characterizations using hydrogen-1 nuclear magnetic resonance, in vitro degradation, as well as thermal and mechanical analysis showed that …

Microfluidic Generated Egf-Gradients Induce Chemokinesis Of Transplantable Retinal Progenitor Cells Via The Jak/Stat And Pi3kinase Signaling Pathways., Uchenna J. Unachukwu, Moira Sauane, Maribel Vazquez, Stephen Redenti

Publications and Research

A growing number of studies are evaluating retinal progenitor cell (RPC) transplantation as an approach to repair retinal degeneration and restore visual function. To advance cell-replacement strategies for a practical retinal therapy, it is important to define the molecular and biochemical mechanisms guiding RPC motility. We have analyzed RPC expression of the epidermal growth factor receptor (EGFR) and evaluated whether exposure to epidermal growth factor (EGF) can coordinate motogenic activity in vitro. Using Boyden chamber analysis as an initial high-throughput screen, we determined that RPC motility was optimally stimulated by EGF concentrations in the range of 20-400 ng/ml, with decreased …