Metallurgy Commons^™

Multi-Project Scheduling Cost Optimization In A Machine Manufacturer Engineer-To-Order, Farizal Farizal, Amar Rachman, Tifani Tandean, Sumarsono Sudarto, Katsuhiko Takahashi

Makara Journal of Technology

This paper discusses the utilization of mixed integer linear programming (MILP) model to optimize cost for multiproject scheduling in a machine maker company. The objective is to minimize total project’s penalty cost and labor cost. The model formulated shows how to achieve the objective i.e. whether to use outsourcing or overtime to finish all projects. The model of multi-project scheduling was solved by Branch & Bound algorithm coded in Lingo 14.0 software. The case study shows that if a company wants to minimize lateness, it should use overtime instead of outsourcing, which minimize total lateness of projects by 144 days …

Analysis Of Arm Movement Prediction By Using The Electroencephalography Signal, Reza Darmakusuma, Ary Setijadi Prihatmanto, Adi Indrayanto, Tati Latifah Mengko, Lidwina Ayu Andarini, Achmad Furqon Idrus

Makara Journal of Technology

Various technological approaches have been developed in order to help those people who are unfortunate enough to be afflicted with different types of paralysis which limit them in performing their daily life activities independently. One of the proposed technologies is the Brain-Computer Interface (BCI). The BCI system uses electroencephalography (EEG) which is generated by the subject’s mental activity as input, and converts it into commands. Some previous experiments have shown the capability of the BCI system to predict the movement intention before the actual movement is onset. Thus research has predicted the movement by discriminating between data in the “rest” …

Texture Analysis Using The Neutron Diffraction Method On The Non Standardized Austenitic Steel Process By Machining,Annealing, And Rolling, Tri Hardi Priyanto, Parikin Parikin, Meijuan Li

Makara Journal of Technology

Austenitic steel is one type of stainless steel which is widely used in the industry. Many studies on austenitic stainless steel have been performed to determine the physical properties using various types of equipment and methods. In this study, the neutron diffraction method is used to characterize the materials which have been made from minerals extracted from the mines in Indonesia. The materials consist of a granular ferro-scrap, nickel, ferro-chrome, ferro-manganese, and ferro-silicon added with a little titanium. Characterization of the materials was carried out in three processes, namely: machining, annealing, and rolling. Experimental results obtained from the machining process …

A Comparison Of American, Norwegian, And Russian Standards In Calculating The Wall Thickness Of Submarine Gas Pipeline, Cindy Dianita, Tatyana Vladimirovna Dmitrieva

Makara Journal of Technology

One of the key issues in the pipeline design is wall thickness calculation. This paper highlights a comparison of wall thickness calculation methods of submarine gas pipeline based on Norwegian Standard (DNV-OS-F101), Indonesian Standard SNI 3474 which refers to American Standard (ASME B31.8), and Russian Standard (VN39-1.9-005-98). A calculation of wall thickness for a submarine gas pipeline in Indonesia (pressure 12 MPa, external diameter 668 mm) gives the results of 18.2 mm (VN39-1.9-005-98), 16 mm (ASME B31.8), and 13.5 mm (DNV-OS-F101).The design formula of hoop stress due to internal pressure is interpreted in different ways for every standard. Only Norwegian …

Maneuverability Of Ships With Small Draught In Steady Wind, Daeng Paroka, Andi Haris Muhammad, Syamsul Asri

Makara Journal of Technology

Wind force and moment may force a ship to drastically decrease its speed and use a large drift angle as well as a large rudder angle in order to maintain its course. Ships with a small draught might have more risk in maneuvering to its point of view compared with a ship with a larger draught. This paper discusses maneuverability of a ship with a small draught in steady wind. The effect of wind on ship speed, drift angle, and rudder angle are investigated in a steady state condition. Five different ratios of wind velocity to ship speed from 1.0 …

Cyclic Behavior Of A Hybrid Light Gauge And Hss Mezzanine Structural System, Michael John Kren

Master's Theses (2009 -)

Cold-formed steel is emerging as an alternative material in the building industry to hot-rolled steel for smaller buildings and indoor structures also called mezzanines. Cyclic testing of a full-scale mezzanine structures composed of cold-formed structural channel beams connected to hollow structural steel (HSS) columns cap plates using wedge expansion anchors at the base plate to generate rotation restraint, is performed in this research. The characteristics of the structure will be explained by displaying full experimental results of structural testing. Unfortunately, limited experimental data outlining the behavior of these structures is available and design criteria is very limited. Thus, there is …

Conversion Casting: Adapter Hub, Joseph M. Coup

All Undergraduate Projects

The concept of conversion casting makes manufacturing major components much more efficient with regards to time and cost. The conversion cast of the adapter hub used in the Victair Mistifier is a major component that requires 8 hours to machine. The existing hub starts from steel stock and then that block of steel is placed into a CNC machine and coded in to create the adapter hub. The manufacturing method changes to a casting for the adapter hub will create a replicated part that requires 1.5 hours of post machining. The intricate design makes a conversion to casting more effective …

Structure And Corrosion Behavior Of Sputter Deposited Ce-Al-O Coating On Al 2024-T3 Alloy Substrates, Yuanyuan Liu, Jiamu Huang, James B. Claypool, Matthew J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

Deposition of Ce-Al-O coatings on Al 2024-T3 alloy substrates was conducted by magnetron co-sputtering of CeO₂ and Al targets. The incorporation of Al into the CeO₂ film resulted in an amorphous or nanocrystalline structure with binding energy states different from Al, Al₂O₃, and CeO₂. Electrochemical measurements indicated that the amorphous or nanocrystalline Ce-Al-O coating increased the corrosion resistance of bare Al 2024-T3 substrates by more than three orders of magnitude and exhibited a very different cathodic and anodic protective mechanism compared to Al and CeO₂ coated and as-polished Al 2024-T3 samples. …

Cryogenic Processing Of Al 7050-T7451 Alloy For Improved Surface Integrity, Bo Huang

Theses and Dissertations--Mechanical and Aerospace Engineering

Al 7050-T7451 alloy with good combinations of strength, stress corrosion cracking resistance and toughness, is used broadly in the aerospace/aviation industry for fatigue-critical airframe structural components. However, it is also considered as a highly anisotropic alloy as the crack growth behavior along the short transverse direction is very different from the one in the long transverse direction, due to the inhomogeneous microstructure with the elongated grains distributed in the work material used in the sheet/plate applications. Further processes on these materials are needed to improve its mechanical and material properties and broaden its applications.

The material with ultra-fine or nano …

Thermomechanical Processing Of Aluminum Micro-Alloyed With Sc, Zr, Ti, B, And C, Cameron Mcnamara

Dissertations, Master's Theses and Master's Reports

Critical exploration of the minimalistic high strength low alloy aluminum (HSLA-Al) paradigm is necessary for the continued development of advanced aluminum alloys. In this study, scandium (Sc) and zirconium (Zr) are examined as the main precipitation strengthening additions, while magnesium (Mg) is added to probe the synergistic effects of solution and precipitation hardening, as well as the grain refinement during solidification afforded by a moderate growth restriction factor. Further, pathways of recrystallization are explored in several potential HSLA-Al systems sans Sc. Aluminum-titanium-boron (Al-Ti-B) and aluminum-titanium-carbon (Al-Ti-C) grain refining master alloys are added to a series of Al-Zr alloys to examine …

A Study On Non-Metallic Inclusions In Foundry Steel Process, Marc Leonard Harris

Masters Theses

"The effects of sample area and automated SEM/EDS feature analysis parameters (step size, magnification and threshold) on nonmetallic inclusion characterization results has been investigated and optimized. A post-processing program was developed to automatically determine average inclusion chemistry, total element concentrations within inclusions, and for generating joint ternary diagrams with size visualization for representing nonmetallic inclusion populations. Using these tools the evolution of nonmetallic inclusions was examined for 4320 steel at a participating industrial steel foundry. The steel was sampled throughout electric arc furnace melting through ladle refining to the final casting where an in-mold sampling procedure was developed to procure …

Nd2fe14b: (Nd1-X Dyx)2 Fe14b Core-Shell Structure Formation By Hot Press Liquid Phase Sintering, Li Chen

Dissertations, Master's Theses and Master's Reports

The purpose of this project is to produce Nd rich core-Dy rich shell grain structure in liquid phase sintered alloys by consolidating Dy rich powder mixed with powder. The technical barrier to producing the core-shell microstructure is that the Dy composition variations will homogenize during the consolidation process. This dissertation is based on the hypothesis that compositional homogenization of the core-shell structure can be minimized if consolidation occurs under applied pressure (hot press liquid phase sintering). The hypothesis is tested by comparing the homogenization of the Dy composition to the degree of consolidation with and without applied pressure. It is …

Investigation Of The Resistance To Demagnetization In Bulk Rare-Earth Magnets Comprised Of Crystallographically-Aligned, Single-Domain Crystallites With Modified Intergranular Phase, Jie Li

Dissertations, Master's Theses and Master's Reports

The research presented in this dissertation investigates whether an increased coercivity of Neodymium-Iron-Boron (Nd2Fe14B) based bulk magnets at elevated temperature (160°C), which is now only obtainable by substituting ~7wt% dysprosium (Dy) for a portion of neodymium (Nd), can be achieved through specific microstructural modifications with decreased Dy concentrations. The approach is to reduce the size of individual crystallographically-aligned grains in the magnet so that each grain can only support a single magnetic domain and to simultaneously dilute the Nd-Fe inter-granular phase present in conventional magnets with a non-Fe-containing, Nd-rich phase (Nd-Cu alloy) in an attempt to partially magnetically isolate the …

The Effect Of Solidification Rate And Solutionizing Quench Rate On The Mechanical Properties And Hardening Response Of Aluminum Alloys: A Quantitative Comparison, Rafael Gil-Figueroa

Dissertations, Master's Theses and Master's Reports

A comparative study of five aluminum alloys was performed to characterize the effect of solidification rate and quench rate on casting microstructure and properties. The alloys were cast in the geometry for Jominy End Quench (JEQ) testing, so as to take advantage of the JEQ test’s ability to give data on multiple quench rates in a single sample and illustrate the quench sensitivity of an alloy. While the Jominy End Quench test has been used in aluminum alloys, the effects of solidification rates have not been assessed in depth. The work done by other studies has either focused on a …

Oxidation Resistance Of Nanocrystalline 316l Stainless Steel Processed By High Pressure Torsion, Kevin J. Meisner

Williams Honors College, Honors Research Projects

High Pressure Torsion (HPT) is a materials processing method used to refine the grain size of metallic materials through the application of simultaneous axial and torsional strain. HPT is reported to result in nanocrystalline structure, which the current scientific literature suggests may improve the high temperature oxidation resistance by enhancing diffusion of solutes, particularly Cr, to the surface to form a protective external oxide scale. If oxidation resistance is improved, this possibly allows the use of 316L in oxidizing environments where more expensive alloys are typically used. However, the influence of grain refinement to nanoscale on various properties have been …

Investigation And Modeling Of Al3(Sc, Zr) Precipitation Strengthening In The Presence Of Enhanced Supersaturation And Within Al-Cu Binary Alloys, Kyle Deane

Dissertations, Master's Theses and Master's Reports

Diffuse Al-Sc and Al-Zr alloys have been demonstrated in literature to be relatively coarsening resistant at higher temperatures when compared with commonly used precipitation strengthening alloys (e.g. 2000 series, 6000 series). However, because of a limited strengthening due to the low solubility of scandium and zirconium in aluminum, and owing to the scarcity and therefore sizeable price tag attached to scandium, little research has been done in the way of optimizing these alloys for commercial applications.

With this in mind, this dissertation describes research which aims to tackle several important areas of Al-Sc-Zr research that have been yet unresolved. In …

Processing Of Al-12si-Tnm Composites By Selective Laser Melting And Evaluation Of Compressive And Wear Properties, Konda Prashanth, Sergio Scudino, Anil Chaubey, Lukas Löber, Pei Wang, Hooyar Attar, Frank Schimansky, Florian Pyczak, Jürgen Eckert

Research outputs 2014 to 2021

Al-12Si (80 vol%)-Ti52.4Al42.2Nb4.4Mo0.9B0.06 (at.%) (TNM) composites were successfully produced by the selective laser melting (SLM). Detailed structural and microstructural analysis shows the formation of the Al6MoTi intermetallic phase due to the reaction of the TNM reinforcement with the Al-12Si matrix during SLM. Compression tests reveal that the composites exhibit significantly improved properties (∼140 and ∼160 MPa higher yield and ultimate compressive strengths, respectively) compared with the Al-12Si matrix. However, the samples break at ∼6% total strain under compression, thus showing a reduced plasticity of the composites. Sliding wear tests were carried out for both the Al-12Si matrix and the Al-12Si-TNM …

Evolution Of Non-Metallic Inclusions In Foundry Steel Casting Processes, Marc Harris, Von Richards, Ronald J. O'Malley, Semen Naumovich Lekakh

Materials Science and Engineering Faculty Research & Creative Works

The evolution of nonmetallic inclusions was examined for 4320 steel at an industrial steel foundry. The steel was followed from electric arc furnace melting through ladle refining to final casting. Timed sampling was performed at all stages of the process. Samples were analyzed using an automated SEM/EDS system. The overall evolution of oxide inclusions in terms of nucleation, growth, and flotation during liquid processing was studied using area fraction and average diameter. Chemical composition evolution was observed using a joint ternary plotting tool developed under this program. It was found that the use of zirconium as an addition for nitrogen/oxygen …

Improving Renewable Energy Transition Acceptance: A Simulation Gaming Approach On A Multi Actor Setting In The Netherlands, Aziiz Sutrisno, Jac A. M. Vennix, Noor Syaifudin

Makara Journal of Technology

The Netherlands have tried very hard to increase their renewable energy sources (RES) shares to fulfill the European Union target in 2050. However, RES performance did not show the expected result as the performance declined in 2009 producing even wider gap compare to the target. The Dutch government’s tried to incorporate all interested stakeholders by forming the Dutch energy transition task force. Nevertheless, the task force’s result is also not showing a desirable trend. Key reasons behind the Dutch low RES performance are the lack of shared understanding and positive attitude toward RES development among interested actors. This research uses …

Dual-Band Singly-Fed Proximity-Coupled Tip-Truncated Triangular Patch Array For Land Vehicle Mobile System, Basari Basari, Josaphat Tetuko Sri Sumantyo

Makara Journal of Technology

This paper proposes a dual-band left-handed circularly polarized triangular-patch array that is developed for land vehicle mobile system aimed at mobile satellite communications. The array consists of six tip-truncated triangular patches, which the first three patches are used for reception and the second three patches are used for transmission purpose. Each of three-patches has a beam pattern that can be switched in three different 120°-coverage beam in azimuth-cut plane at a minimum targeted gain at a desired elevation angle. The targeted minimum gain of the array is 5 dBic, in order for data communications with a large geostationary satellite can …