Metallurgy Commons^™

Shaft Torsional Vibration Response Of Vertical Axis Ocean Current Turbine Model Due To Torque Excitation, Adi Wirawan Husodo, I Ketut Aria Pria Utama, I Made Ariana

Makara Journal of Technology

Shaft Torsional Vibration Response of Vertical Axis Ocean Current Turbine Model Due to Torque Excitation. The current research aimed to study the torsional vibration response of Vertical Axis Ocean Current Turbine due to randomly torque excitation pattern, owing to the variety of ocean current velocity. The turbine model is composed of 3 aluminum blades of NACA 0018 connected to steel shaft. Turbine dimensions are 10 cm of chord, 1.8 cm of chamber and 100 cm of span. The variation of ocean current velocity is 0.5 m/s, 1.0 m/s, 1.5 m/s, 2.0 m/s, 2.5 m/s and 3.0 m/s. The Model has …

Characterization Of Inconel 718: Using The Gleeble And Varestraint Testing Methods To Determine The Weldability Of Inconel 718, Nathaniel Oscar Knock

Master's Theses

Nickel based superalloys were developed to withstand the severe thermal and mechanical environment associated with rocket propulsion systems and jet engines. In many alloy systems the strength of a component rapidly deteriorates as the operating temperature increases. Nickel based superalloys, however, retain strength over a range of temperatures which includes the operating range for many propulsion systems. This improved performance is accomplished by a combination of solid-solution strengthening, precipitation strengthening and grain-boundary strengthening. Furthermore, super-alloy systems are designed for ease of fabrication, to include machining, welding and heat treating. Inconel 718 was developed to overcome problems with post-weld cracking that …

Analysis Of Microstructural Evolution During Friction Stir Welding Of Ultrahigh-Strength Steel, M. Ghosh, K. Kumar, R. S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Friction stirs lap-welded advanced high-strength M190 steel exhibited formation of lath martensite at weld nuggets, a ferrite layer at faying surfaces and a ferrite-pearlite microstructure at the bottom of the stir zone. the phase transformation was governed by severe plastic deformation in the austenitic region followed by cooling. the strain rate and peak temperature played key roles in controlling the prior-austenitic grain size and were correlated to the Zener-Hollomon parameter. an empirical relationship has been obtained for dynamically recrystallized austenite grains. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effect Of Friction Stir Processing On Microstructure And Tensile Properties Of An Investment Cast Al-7si-0.6mg Alloy, Saumyadeep Jana, Rajiv S. Mishra, John A. Baumann, Glenn J. Grant

Materials Science and Engineering Faculty Research & Creative Works

Friction stir processing (FSP) is emerging as a promising tool for microstructural modification. the current study assesses the effects of FSP on the microstructure and mechanical properties of an investment cast Al-7Si-Mg alloy. FSP eliminates porosity and significantly refines eutectic Si particles. the extent of particle refinement varied with changes in processing conditions. a high tool rotation rate and a low-to-intermediate tool traverse speed generated a higher volume fraction of finer particles. Tensile ductility changed significantly as a result of FSP, whereas ultimate tensile strength improved only marginally. Yield strength was similar in both cast and FSP samples under various …

The Effects Of Applied Strain And Heat Treatment On The Properties Of Niti Wire During Shape Setting, Frank Zapoticla

Master's Theses

NiTi components are commonly subjected to thermo-mechanical heat treatments during production and fabrication. This study investigates the effects of applied strain of 0-10% and heat treatments of 300-600ºC for times of 2-30 minutes during shape-setting of Ti–50.8 at% Ni wire with a nominal diameter of 0.495 mm and an initial transition temperature, Af, of 12ºC. Strain was applied prior to heat treatments by coiling NiTi wire, essentially producing coiled springs, around different diameter steel mandrels to obtain different strain levels. The samples of NiTi wire under applied strain were heat treated in a salt bath, followed by a rapid quench. …

Structural And Magnetic Properties Of Neodymium–Iron–Boron Clusters, Jeremy J. Anderson

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Using inert gas condensation techniques the properties of sputtered neodymium-iron-born clusters were investigated. A D.C. magnetron sputtering source created vaporous Nd-Fe-B which was then condensed into clusters and deposited onto silicon substrates. A composite target of Nd-Fe-B discs on an iron plate and a composite target of Nd-(Fe-Co)-B were utilized to create clusters. The clusters were coated with a carbon layer through R.F. sputtering to prevent oxidation.

Samples were investigated in the TEM and showed a size distribution with an average particle diameter of 8.11 nm. The clusters, upon deposition, were amorphous as indicated by diffuse diffraction patterns obtained through …

The Effects Of Carbon, Boron And Vanadium On The Microstructural Evolution And Hardness Of Steel-Based Hardfacing Alloys, Kyle Rafa

Materials Engineering

Current hardfacing alloys provide insufficient wear resistance due to either cracking or significant material wear. To increase wear resistance of steel-based hardfacing alloys, the effects of composition on microstructure and hardness were investigated in a progression of alloys. Initially, seven new alloys were prepared varying the carbon-boron ratio with the total constant at 3 wt%. Small arc-melt cast circular ingots were produced roughly 1 x 0.5 inches. Metallography provided insufficient phase magnification, thus a SEM equipped with EDS was used, allowing for microstructure and phase composition analysis. Four distinct carbide phases were found and image analysis software allowed for carbide …

Characterization Of Aluminum-Boron Carbide Particulate Metal Matrix Composites, Eric Blank

Materials Engineering

The analysis of die-cast 380 aluminum-boron carbide particulate metal matrix composites (MMC) was performed in order to see if the samples had the required tensile strength of 300 MPa. 10wt% B4C die-cast samples were produced and tested. Half were heat treated to the T6 condition and the others were left as cast. Using ASTM standard B 557M it was found that the average tensile strength for the as-cast samples was 130 MPa and the heat treated samples had a tensile strength of 93 MPa. These values were both lower than expected. The heat treated samples were not expected to have …

Effects Of A Solution Anneal Quench Delay On The Heat Treatment Response Of Aluminum 2219-T6, Daniel James Filomeo

Materials Engineering

The ageing response for aluminum 2219-T6 was investigated to determine the effects a quench delay (QD) could have on tensile properties. Before testing commenced, furnace surveys were conducted to ensure they could meet the required temperature stability of + 10˚F (+6˚C). MIL-H-6088 specified a maximum quench delay of 15 seconds for parts thicker than 2.29 mm (0.090 in). An investigation was conducted on how different quench delay times changed the ageing response of T6 heat treated for Al 2219. Heat treatments were performed according to the ASM Handbook. Preliminary tests were performed on 1-1.5 in. cube blocks of Al 2219 …

Mechanical Behavior Of Alloy 230 At Temperatures Relevant To Ngnp Program, Sudin Chatterjee

UNLV Theses, Dissertations, Professional Papers, and Capstones

Identification and selection of suitable structural materials for heat exchanger application within the purview of the next generation nuclear plant (NGNP) program constitute a major challenge. This challenge stems from the lack of many desired metallurgical and mechanical properties of conventional metallic materials and alloys for applications at temperatures approaching 950 oC. Nickel (Ni)-base Alloy 230 has been highly recommended as a suitable structural material for such application due to its excellent resistance to high-temperature plastic deformation and superior corrosion resistance in many hostile environments. Systematic studies on tensile, fracture toughness, creep, stress-rupture and creep-fatigue behavior of this alloy have …

Investigation Of Creep Threshold Stresses Using In Situ Tem Straining Experiment In An Al-5y2o3-10sic Composite, S. P. Deshmukh, Rajiv S. Mishra, I. M. Robertson

Materials Science and Engineering Faculty Research & Creative Works

Creep behavior of metal matrix composites is similar to dispersion strengthen alloys and characterized by the presence of a threshold stress below which the creep rate is negligible. This threshold stress is attributed, at least in dispersion-strengthened alloys, to dislocation particle interactions in which the detachment of the dislocations from the particle is the rate-limiting step. Creep experiments were performed on an Al-5Y₂O₃-10SiC composite in the temperature range of 473 and 573 K and the nature of the dislocation-particle interaction was determined by performing in situ straining experiments at elevated temperature in a transmission electron microscope. …

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 …

A Simple Technique For Surface Area Determination Through Supercritical Co2 Adsorption, Mahmud Sudibandriyo

Makara Journal of Technology

The measurement of specific surface area of porous materials has long been important in physical sciences and is currently growing in importance in applied and environmental science. Numerous systems have been developed for surface area measurement by gas adsorption. Commercial systems are available which can measure a wide range of absolute surface area with relative ease. However, their cost is often prohibitive. In this study, an inexpensive apparatus for surface area measurement has been set up to be used for measuring supercritical adsorption of CO2. The Ono-Kondo Lattice model was used to represent the adsorption isotherm and to determine the …

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 …

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 …

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, …