Materials Science and Engineering Commons^™

Fishing Catch And Catch Rate Assesment Of Mini Trawl, Trapnet And Setnet Fisheries, Muhammad Firdaus

Makara Journal of Technology

Fishing Catch and Catch Rate Assesment of Mini Trawl, Trapnet and Setnet Fisheries. This paper is aimed at assessing fishing catch and catch rate of the dragged gear on shrimp, trapnet, and setnet fisheries in Tarakan. The catch and effort data (number and species) and the fishing time of captured units were used in this qualitative analysis of fishing catch and catch rate to describe catch composition and catch rate from three catch fishery units in Tarakan. The result of the research shows that in the catching operation the dragged gear on shrimp has two main catch targets, which are …

Light-Activation Influence On The Thermal Analysis Of A Resin-Modified Glass-Ionomer, Raksha Srinivas

Master's Theses (2009 -)

The acid-base and light polymerization reactions in resin modified glass ionomers (RMGI) have been shown to compete and possibly inhibit one another during early RMGI development. Earlier beginning times of light polymerization initiation may limit the acid-base reaction and if time allowed for the acid-base components to react is increased, the extent of light cure reaction may be lesser. The thermal behavior of a commercially available RMGI was investigated in relation to a light initiation regimen using a differential scanning calorimeter (DSC). The relationship between delay in light initiation or no light initiation and the resultant set matrix of the …

Electric Field Computation Of Wet Insulating Surfaces, Bhargavi Sarang

Electrical & Computer Engineering Theses & Dissertations

High voltage outdoor insulators form the backbone of modem power systems and therefore play a pivotal role in reliable supply of power. The presence of water droplets/films due to rain, fog, etc. enhances the electric field intensity and leads to electrical breakdown subsequently affecting the longevity of the insulator. The magnitude of surface E-fields necessary for initiation of electrical breakdown is a function of water repellent characteristic of an insulator called hydrophobicity. Thus, knowledge of field distribution around water droplets/films at various hydrophobic levels is significant in designing a better insulating material.

The current research analyzed electric field distributions on …

Ontology-Based Automatic Classification For News Articles In Indonesian Language, Prajna Wira Basnur, Dana Indra Sensuse

Makara Journal of Technology

Ontology-Based Automatic Classification for News Articles in Indonesian Language. Searching specific information will be difficult if relying only on query. Choosing less specific queries will result in a lot of irrelevant information fetched by the system. One of the most successful ways to overcome this problem is to perform document classification based on the topic. There are many methods that can be used to conduct such a classification, such as using statistical and machine learning approaches. However, those document classification methods require training the data or learning the documents. In this study, the authors attempted to classify documents using a …

Particle Filter With Binary Gaussian Weighting And Support Vector Machine For Human Pose Interpretation, Indah Agustien, Muhammad Rahmat Widyanto, Sukmawati Nur Endah, Tarzan Basaruddin

Makara Journal of Technology

This paper proposes human pose interpretation using particle filter (PF) with Binary Gaussian Weighting and support vector machine (SVM). In the proposed system, particle filter is used to track a human object, then this human object is skeletonized using thinning algorithm and classified using SVM. The classification is to identify human pose, whether it is normal or abnormal behavior. Here particle filter is modified through weight calculation using Gaussian distribution to reduce the computational time. The modified particle filter consists of four main phases. First, particles are generated to predict target’s location. Second, the weight of certain particles is calculated …

Maintenance Activity Planning By Reability Centered Maintenance Ii Method, Rachmad Hidayat, Nachnul Ansori, Ali Imron

Makara Journal of Technology

Maintenance Activity Planning by Reability Centered Maintenance II Method. This research discusses maintenance activity planning using the RCM II method to evaluate failure function risk on compresor screw. The calculation of maintenance time is performed by considering maintenance and repair costs. The risk evaluation result with RPN shows that the critical component that needs to get the main priority in applying maintenance on compresor screw is function disorder on timeworn piston and on the broken outgoing air sponge’s filter that receives RPN 45. The optimum maintenance time calculation is applied on components that undergo scheduled restoration and scheduled discard task …

Software Design Of Mobile Antenna For Auto Satellite Tracking Using Modem Correction And Elevation Azimuth Method, Djamhari Sirat, Muhamad Asvial, Arman Djohan Diponegoro, Himawan Sidharta

Makara Journal of Technology

Software Design of Mobile Antenna for Auto Satellite Tracking Using Modem Correction and Elevation Azimuth Method. Pointing accuracy is important in satellite communication. Because the satellite’s distance to the surface of the earth's satellite is so huge, 1 degree of pointing error will make the antenna unable to send data to satellites. To overcome this, the auto-tracking satellite controller is made. This system uses a microcontroller as the controller, with the GPS as the location indicator of the antenna, a digital compass as the beginning of antenna pointing direction, a rotary encoder as azimuth and elevation censor, and a modem …

Petroleum Degradation In Soil By Thermophilic Bacteria With Biopile Reactor, Astri Nugroho, Edison Effendi, Yulius Karonta

Makara Journal of Technology

Crude oil degradation has been carried out using biopile reactor in total petroleum hydrocarbon (TPH) concentration of 5%, 10% and 15%. The thermophilic microorganisms used from isolation result and identification are Aeromonas salmonicida, Bacillus pantothenticus, and Stenotrophomonas maltophilia. The biodegradation of biopile reactor is done by various concentrations of TPH, total plate count (TPC), and volatile suspended solid (VSS) per day for 30 days. The biodegradation of kinetic parameter calculated consists of μ, μm, Y, Yt, Yobs, Kd, Ks from TPH concentration decision, and TPC and VSS in every microorganism with t (observation time) of 0 hour to 168 hours. …

Ergonomic Analysis Of Ui’S Bicyclesusing Posture Evaluation Index (Pei) Method In Virtual Environment, Erlinda Muslim, Boy Nurtjahyo, Zulkarnain Zulkarnain, Liza Afrinotha

Makara Journal of Technology

Ergonomic Analysis of UI’s Bicycles Using Posture Evaluation Index (PEI) Method in Virtual Environment. This research was conducted to study the ergonomic aspect of University of Indonesia’s bicycles in virtual environment. Software Jack 6.0 was used to analyze it. PEI was used as an approach that integrated the results of three methods: lower back analysis (LBA), ovako working posture analysis (OWAS), and rapid upper limb assessment (RULA). The research objective is to evaluate the existing design of University of Indonesia’s bicycles and to determine the most ergonomic redesign which concerns handlebar height and saddle height modification. The result showed that …

Morphological Evolution Of Single-Crystal Ultrathin Solid Films, Mikhail Khenner

Mathematics Faculty Publications

An introduction to mathematical modeling of ultrathin solid films and the role of such modeling in nanotechnologies: Educational presentation for senior physics majors

Morphological Evolution Of Single-Crystal Ultrathin Solid Films, Mikhail Khenner

Mathematics Faculty Publications

An introduction to mathematical modeling of ultrathin solid films and the role of such modeling in nanotechnologies: Educational/Research presentation for senior physics majors

Slip Boundary Conditions For The Moving Contact Line In Molecular Dynamics And Continuum Simulations, Nikolai V. Priezjev, Anoosheh Niavarani

Mechanical and Materials Engineering Faculty Publications

The problem of the moving contact line between two immiscible fluids on a smooth surface is revisited using molecular dynamics (MD) and continuum simulations. In MD simulations a finite slip is allowed by choosing incommensurate wall-fluid densities and weak wall-fluid interaction energies. The shear stresses and velocity fields are extracted carefully in the bulk fluid region as well as near the moving contact line. In agreement with previous studies, we found slowly decaying partial slip region away from the contact line. In steady-state shear flows we extract the friction coefficient along the liquid-solid interface, the local slip length, and the …

Rubidium Recycling In A High Intensity Short Duration Pulsed Alkali Laser, Wooddy S. Miller

Theses and Dissertations

Laser induced fluorescence was used to study how pump pulse duration and alkali recycle time effects maximum power output in a Diode Pumped Alkali Laser (DPAL) system. A high intensity short pulsed pump source was used to excited rubidium atoms inside a DPAL-type laser. The maximum output power of the laser showed a strong dependence upon the temporal width of the pump pulse in addition to the input pump intensity. A linear relationship was observed between the maximum output power and the pulse width due to the effective lifetime of the excited state, defined as the time it takes for …

Optical And Electrical Characterization Of Bulk Grown Indium-Gallium-Arsenide Alloys, Austin C. Bergstrom

Theses and Dissertations

Advances in crystal growth techniques have allowed increased quality in growth of bulk ternary In_xGa_1-xAs. Here, the optical and electrical properties of samples grown through the vertical Bridgman (or multi-component zone melting growth) method have been investigated through photoluminescence spectroscopy and Hall effect measurements. Indium mole fractions varied from 0.75 for 1. Hall effect measurements at temperatures ranging from 10 to 300 K revealed moderate n-type doping with carrier concentrations ranging from 1.5 to 9.6×10¹⁶ cm^-3 at 10 to 15 K. Carriers from deep donor levels became appreciable between 50 and 100 K. Hall …

Afm-Patterned 2-D Thin-Film Photonic Crystal Analyzed By Complete Angle Scatter, Nicholas C. Herr

Theses and Dissertations

The purpose of this research was to use an atomic force microscope (AFM) to generate a 2-D square array of sub-wavelength surface features from a single material over a region large enough to permit optical characterization. This work is an extension of previous AFIT nano-patterning work and is in response to the small subunit sizes demanded for the production of optical metamaterials and photonic crystals. A diamond nano-indentation AFM probe was used to produce a 325-μm by 200-μm array of indentations in a 120-nm thick polystyrene film deposited on silicon. Indentation spacing of 400 nm produced well-defined surface features with …

Hard Collisions In Rubidium Using Sub-Doppler Spectroscopy, Douglas E. Thornton

Theses and Dissertations

To better understand the laser kinetics of an alkali gain medium, hard collisions, or velocity-changing collisions, has been studied and a velocity-changing collisional rate has been calculated. Previous works have studied these collisions, but no rate has been calculated. Using the precise tool of sub-Doppler spectroscopy, atomic hard collisions can be observed. The collected spectra are fitted with two different line shapes to demonstrate the accuracy of this method. From the fits, the number of hard collisions can be extracted. The time scale of the hard collisions in rubidium is interpolated by varying the chopping frequency of the pump beam, …

Characterization And Measurement Of Passive And Active Metamaterial Devices, Christopher A. Lundell

Theses and Dissertations

This document addresses two major obstacles facing metamaterial development: uncertainty in the characterization of electromagnetic field behavior in metamaterial structures and the relatively small operational bandwidth of metamaterial structures. To address the first obstacle, a new method to characterize electromagnetic field behavior in a metamaterial is presented. This new method is a bistatic radar cross section (RCS) measurement technique. RCS measurements are well-suited to measuring bulk metamaterial samples because they show frequency dependence of scattering angles and offer common postprocessing techniques that can be useful for visualizing results. To address the second obstacle, this document characterizes the effectiveness of an …

Gerber Project For Lockheed Martin, Andrew Callahan, Sean Lawyer

Industrial Technology and Packaging

Lockheed Martin, the world’s premier aerial combat vehicle manufacturer was pressed to find an eco-friendly way to package their impregnated epoxy. In the current system, the epoxy would be cut on the Gerber table to a pre-determined length and then sandwiched inside of two corrugated fiberboard sheets for storage inside of a freezer. The current process was not only labor intensive, but the corrugated fiberboard had to be disregarded after one use. In conjunction with the Cal Poly San Luis Obispo Packaging program and Melmat Incorporated, we were able to find a corrugated plastic substrate to replace the currently non-reusable …

Effects Of Crystallographic Orientation On The Early Stages Of Oxidation In Nickel And Chromium, Louis P. Bonfrisco, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Surface orientation plays an important role in the oxidation behavior of single crystals where studies have found the relative oxidation rates for surfaces with different orientations. However, most materials are polycrystalline and contain myriad orientations that contribute to the overall oxidation process. Here we determine the effects of orientation on the early stages of oxidation behavior as a function of surface orientation for polycrystalline nickel (face-centered cubic) and chromium (body-centered cubic). After high temperature oxidation, the oxide topography is characterized using optical profilometry and the underlying microstructure is characterized with electron backscatter diffraction (EBSD). By correlating results from EBSD and …

Peak Stir Zone Temperatures During Friction Stir Processing, Sprinivasan Swaminathan, Keiichiro Oh-Ishi, Alexander P. Zhilyaev, Christian B. Fuller, Blair London, Murray W. Mahoney, Terry R. Mcnelly

Materials Engineering

The stir zone (SZ) temperature cycle was measured during the friction stir processing (FSP) of NiAl bronze plates. The FSP was conducted using a tool design with a smooth concave shoulder and a 12.7-mm step-spiral pin. Temperature sensing was accomplished using sheathed thermocouples embedded in the tool path within the plates, while simultaneous optical pyrometry measurements of surface temperatures were also obtained. Peak SZ temperatures were 990 ⁰Cto 1015 ⁰C (0.90 to 0.97 TMelt) and were not affected by preheating to 400⁰C, although the dwell time above 900 ⁰C was increased by the preheating. Thermocouple data suggested little variation in …

Functionally Graded Materials By Laser Metal Deposition (Preprint), Syamala R. Pulugurtha, Joseph William Newkirk, Frank W. Liou, Hsin-Nan Chou

Materials Science and Engineering Faculty Research & Creative Works

Fabrication of functionally graded materials (FGMs) by laser metal deposition (LMD) has the potential to offer solutions to key engineering problems over the traditional metalworking techniques. But the issues that need to be addressed while building FGMs are intermixing in the layers and cracking due to the residual stresses. This paper is to present the study of the effect of process parameters (laser power and travel speed) on the degree of dilution between the substrate (or, previous layer) and powder material for few metallurgical systems.

The Strength Of Silicate Glasses: What Do We Know, What Do We Need To Know?, Charles R. Kurkjian, Prabhat K. Gupta, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

In the last few years, there has been increased interest in methods to improve the practical strength of inorganic glasses. during this same time period, new theoretical and experimental techniques have appeared. in this paper, we discuss this interest and indicate how and where these new techniques may help us to achieve our objective to increase the practical strength of glass. Our ability to measure the intrinsic inert strength of glass fibers as well as the development of stresses around indentations and scratches now allows us to attack these two important issues experimentally. Likewise, major advances have been made in …

Self-Activating Safety Mechanisms For Li-Ion Batteries, Xin-Ping Ai, Yu-Liang Cao, Han-Xi Yang

Journal of Electrochemistry

The safety concerns of LIBs are considered to be a main obstacle to their high rate or large capacity applications in electric vehicles.This paper describes briefly our research works on the development of self-activating safety mechanisms for LIBs,including redox shuttle,potential-sensitive separator,temperature-sensitive electrode,and fire-retardent electrolyte.The problems and future in this research area are also discussed.

Preparation And Characterization Of Sulfur/Mesoprous Carbon Composite Cathodes, Wen-Hua Zhang, Yao Chen, Xin-Ping Ai, Yu-Liang Cao

Journal of Electrochemistry

A sulfur/mesoporous carbon composite was prepared by thermally treating a mixture of sublimed sulfur and mesoporous carbon. The microstructure of the mesoporous carbon was characterized by BET analysis and X-ray diffraction(XRD). The electrochemical performance of the S/C composite as cathode materials was evaluated by the galvanostatic method. The results confirmed that the mesoporous carbon could not only greatly enhance the electrochemical activity of sulfur electrode, but also effectively confine the diffusion of dissolved polysulfides in organic electrolyte. As a result,the S/C composites showed high capacity, good cycle performance and excellent rate capability. The specific capacity of the S/C composite was …

Effects Of Different Carbon Sources On Performance Of Li3V2(Po4)3/C Composite Cathode Materials, Kai-Yuan Liu, Jian-Shu Huang, Li Yang

Journal of Electrochemistry

The monoclinic Li₃V₂(PO₄)₃ cathode materials were prepared by carbothermal reduction method,with methyl cellulose, chitosan(crab shells) or glucose anhydrous as carbon sources, respectively.The crystal structures, morphologies and the electrochemical performances were characterized by XRD, SEM and electrochemical measurement. The XRD patterns show that the samples obtained at 800 ℃ for 6 h have a pure monoclinic structure,which indicates that the carbon exists in amorphous phase. Electrochemical measurements show that the difference of carbon sources has a significant influence on the electrochemical properties of the materials. The Li₃V₂(PO₄)_{3 …}

Performance Of Sulfur-Super Conductive Carbon Black Composite In Electrolyte Mixed With Room Temperature Ionic Liquid, Bo Zhang, Si-Ting Chen, Xue-Ping Gao

Journal of Electrochemistry

The sulfur-super conductive carbon black composite was prepared as cathode material of lithium/sulfur battery.The composite was characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),and electrochemical impedance spectroscopy(EIS).The sulfur composite shows a high discharge capacity and a good cycle performance in electrolyte mixed with 50% of room temperature ionic liquid.In particular,the discharge capacity of the composite was stabilized at 483.6 mAh/g after 50 cycles.

Electrochemical Properties Of Ni(Oh)2 Doped By Nio, Fei-Biao Chen, Bo-Rong Wu, Wei-Feng An, Zhao-Jun Yang, Feng Wu, Shi Chen

Journal of Electrochemistry

The Ni(OH)₂ cathode material of MH/Ni was doped by NiO,which behaves as a capacitor and can improve the charge-discharge rate capacity of Ni(OH)₂.The electrochemical properties of Ni(OH)₂ was characterized by charge-discharge curves and cyclic voltammetry.The results showed that the material had the best discharge property when doped by 5% NiO,and the discharge specific capacity could reach 310.1 mAh/g at 0.2 C rate and remianed 79.5% at 3 C rate.The difference oxidation and reduction potentials between the of the battery was 164 mV when the Ni(OH)₂ was doped by 5% NiO,which showed a good cyclic property.

Investigation Of Ceo2 As Cathode Electrocatalyst For Direct Borohydride Fuel Cell, Xue-Min Ni, Ya-Dong Wang, Mu Pan

Journal of Electrochemistry

The performance of CeO₂ as oxygen reduction electrocatalyst in direct borohydride fuel cell was investigated.The experimental results indicate that CeO₂ shows significant electrocatalytic performance for oxygen reduction and exhibits no observed promotion effect on hydrolysis or electro-oxidation of BH₄^-.The power density of experimental one-compartment fuel cell with CeO₂ as cathode electrocatalyst can reach a 67.8 mW·cm^-2 at room temperature.

Preparation And Electrochemical Behavior Of Li4Ti5O12 Nanosheets As Anode Material For Lithium Ion Battery, Yi-Fei Wang, Yu-Feng Tang, Zheng Qiu, Li Yang

Journal of Electrochemistry

Spinel lithium titanate(Li₄Ti₅O₁₂) nanosheets with a size range of 200 ～400 nm were synthesized by hydrothermal process from the amorphous hydrous titanium oxide precursors.The as-prepared products were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The electrochemical behaviors of Li₄Ti₅O₁₂ electrode in conventional organic electrolyte and ionic liquid electrolyte were investigated by using cyclic voltammetry,galvanostatic charge-discharge and AC impedance techniques.The experimental results indicate that the as-prepared nanostructured Li₄Ti₅O₁₂,evaluated as anode material,exhibited good reversibility and cycle performance.It is expected to be a …

Synthesis Of High-Performance Lini1/3Co1/3Mn1/3O2 Cathode Materials Via Azeotropic Distillation Method, Sheng-An Xia, Li-Xia Yuan, Ze Yang, Zhao-Hui Wang, Yun-Hui Huang, Shuang Li, Wu-Xing Zhang, Ya-Bin Meng, Wei-Gong Zheng

Journal of Electrochemistry

Layered LiNi_1/3Co_1/3Mn_1/3O₂ is one of the most promising alternative materials for LiCoO₂ in lithium ion batteries due to its low cost,large capacity and excellent cyclability.In this paper,LiNi_1/3Co_1/3Mn_1/3O₂ was synthesized via azeotropic distillation method with isobutyl alcohol as an azeotropic agent.The structure and surface morphology were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM),respectively.The as-prepared LiNi_1/3Co_1/3Mn_1/3O₂ shows a layered α-NaFeO₂ structure;the particles are small and uniformly distributed.As compared with the sample prepared by traditional method,the present cathode material …