Metallurgy Commons^™

Probabilistic Fatigue Life Prediction Model For Alloys With Defects: Applied To A206, R. Kapoor, Vittal S. Rao, R. S. Mishra, J. A. Baumann, G. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

A model for the prediction of fatigue life based on the statistical distribution of pores, intermetallic particles and grains is presented here. This has been applied to a cast Al alloy A206 before and after friction stir processing (FSP). the model computes the probability of initiating a small crack based on the probability of finding combinations of defects and grains on the surface. Crack initiation and the propagation life of small cracks due to these defect and grain combinations are computed and summed to obtain the total fatigue life. the defect and grain combinations are ranked according to total fatigue …

Growth Of Oriented Nickel-Manganese-Gallium Single Crystals Via The Bridgman Method, Douglas Leroy Kellis

Boise State University Theses and Dissertations

A Bridgman furnace was designed and built to grow oriented single crystals of nickel-manganese-gallium. The starting alloys were produced from high purity elements. The compositions of the alloys and single crystals were determined with energy dispersive x-ray spectroscopy. Oxygen concentration of the starting elements, the alloys, and single crystal were determined with the LECO combustion method. Starting seeds were produced from single crystal ingots produced at ETH Zurich, Switzerland, and from a single crystal grown from these seeds. Crystallographic orientation of the starting seeds and the single crystals were determined with x-ray diffraction. Mechanical testing was performed on a single …

The Solvent Effectiveness On Extraction Process Of Seaweed Pigment, Warkoyo Warkoyo, Elfi Anis Saati

Makara Journal of Technology

Eucheuma cottonii seaweed is a species of seaweed cultured in Indonesian waters, because its cultivation is relatively easy and inexpensive. It has a wide variety of colors from green to yellow green, gray, red and brown, indicating photosynthetic pigments, such as chlorophyll and carotenoids. An important factor in the effectiveness of pigment extraction is the choice of solvent. The correct type of solvent in the extraction method of specific natural materials is important so that a pigment with optimum quality that is also benefical to the society can be produced. The target of this research is to obtain a high …

Circuit Design For Sensor Detection Signal Conditioner Nitrate Content, Robeth Viktoria Manurung, Aminuddin Debataraja, Hiskia Hiskia

Makara Journal of Technology

Circuit Design for Sensor Detection Signal Conditioner Nitrate Content. Nitrate is one of macro nutrients very important for agriculture. The availability of nitrate in soil is limited because it is very easy to leaching by rain, therefore nitrate could be contaminated ground water by over-process of fertilizer. This process could also produce inefficiency in agriculture if it happened continuesly without pre-analysis of farm field. The answer those problems, it is need to develop the ion sensor system to measure concentrations of nitrat in soil. The system is consist of nitrate ion sensor device, signal conditioning and data acquisition circuit. The …

Production Of Lovastatin And Sulochrin By Aspergillus Terreus Using Solid State Fermentation, Rizna Triana Dewi, Nina Artanti, Hani Mulyani, Puspa Dewi Narrij Lotulung, Minarti Minarti

Makara Journal of Technology

Lovastatin is an anti-cholesterol agent that was produced by Aspergillus terreus using solid state fermentation (SSF). During this fermentation process, sulochrin is also produced as an unwanted co-metabolite. However, our previous result showed that sulochrin had potential as antidiabetes because it is an inhibitor agent of α-glucosidase. In this paper, we reported our observation on lovastatin and sulochrin production pattern in relation with inhibitor α-glucosidase activity during eleven days fermentation of A. terreus koji (SSF) ethyl acetate extract. Koji obtained from solid state fermentation with rice as the substrate and incubated at room temperature, sample is taken daily for eleven …

The Zonation Of Abration Speed Characteristics And Its Handling Technique Of Jalinbar Of North Bengkulu As Vital Band Transportation, Suwarsono Suwarsono, Supiyati Supiyati, Suwardi Suwardi

Makara Journal of Technology

The Zonation of Abration Speed Characteristics and its Handling Technique of Jalinbar of North Bengkulu as Vital Band Transportation. Jalinbar Bengkulu is a vital infrastructure for traffic service, goods, agriculture products, mining, plantation and oils distribution. Abration due to scour of seawater often make these roads jammed and discrupts the peoples economy movement. The aims of this research was to investigate the abration speed of all segment of Jalinbar. The research method was a combination of two methods: A determination of swash energy of sea water using photometer and determination of rocks binding energy using douche method. The result shows …

The Formation Design Of Noise Reducers From Plywood, Foam, Tray, Dan Coconut Fiber For Static Sources, Melati Ferianita Fachrul, Wisnu Eka Yulyanto, Asharani Merya

Makara Journal of Technology

The Formation Design of Noise Reducers from Plywood, Foam, Tray, dan Coconut Fiber for Static Sources. Research was conducted in a semi-anechoic room using a method referring to the ISO 3745. The design used is the Hemisphere in which the source of noise is analogous to engines in an industry. The value reduction in the rate of sound power is obtained by comparing the sound power level before and after control is given. The noise control test materials used consist of layers of plywood, foam, fiber and tray (egg box). The effectiveness of these materials is tested by measuring the …

Natural Gas As Petroleum Fuel Substitution: Analysis Of Supply-Demand Projections, Infrastructures, Investments And End-User Prices, Abdul Qoyum Tjandranegara, Arsegianto Arsegianto, Widodo Wahyu Purwanto

Makara Journal of Technology

The petroleum fuels (PF) subsidy has long burdens the government spending, and discourages less expensive energy usage such as natural gas (NG). Exporting NG and importing the more expensive PF products cause financial losses to Indonesia. The lack of NG infrastructure is the main hurdle in maximizing domestic NG usage and so does the perception of its high investment costs burdening government spending and pushing the NG transportation cost up. This study calculates the required NG infrastructure and its investments for several levels of PF substitutions up to 2030. To balance the NG demands, the supply from each field and …

The Synergy Of Recombinant Xylanolytic Enzyme On Xylan Hydrolysis, One Asmarani, Bambang Prajogo Eko Wardojo, Ni Nyoman Tri Puspaningsih

Makara Journal of Technology

Microbial xylanases or xylanolytic enzyme have received considerable attention over the last years owing to a multitude of possible applications. These enzymes have potential in the biodegradation of lignocellulosic biomass to fuels, chemicals, fruit juice, animal feed and in improving rumen digestion. More recently, the use of xylanases as bleaching agent in the pulp and paper industry has been suggested to replace of some of the chemicals presently used for this purpose. Such applications could have an important positive impact on the environment. The purpose of this research was determining the synergy of 3 recombinant xylanolytic enzymes (β-xylosidase, exo-xylanase and …

Cradle To Gate Simple Life Cycle Assessment Of Biodiesel Production In Indonesi, Akhmad Hidayatno, Teuku Yuri M. Zagloel, Widodo Wahyu Purwanto, Carissa Carissa, Lindi Anggraini

Makara Journal of Technology

The focus of this research is to analyze potential environmental impact in the supply chain of palm oil biodiesel industries. Simple Life Cycle Assessment (LCA) is applied to analyze impacts, produced by the three main units in the supply chain of Palm-Oil-based Biodiesel, which are Palm Plantation, CPO mill, and Biodiesel Plant. We developed LCA calculation model using spreadsheet software, used to assess a number of input scenarios to evaluate the best scenario, in variation of: land quality, land area and the rate of clearing, land clearing technique and type of the original land. The biggest potential environmental impact is …

Characterization Of Surface Active Shell Charcoal Nyamplung Seeds (Calophyllum Inophyllum Linn), Santiyo Wibowo, Wasrin Syafi, Gustan Pari

Makara Journal of Technology

Characterization of Surface Active Shell Charcoal Nyamplung Seeds (Calophyllum inophyllum Linn). Chemical and physical activation of nyamplung shell with 0%, 5%, and 10% H3PO4 for 60 and 120 minutes has been carried out to prepare activated charcoal. The purpose of this experiment was to look into the characteristic of nyamplung shell activated charcoal surface. Nyamplung shell was carbonized into charcoal, then activated by immersion in H3PO4 solution using 0%, 5% and 10%, for 24 hours, and heated in retort at two temperatures (700 and 800 oC) and two duration (60 and 120 minutes). The material were characterized by fourier transform …

An Investigation Into The Resistance/Powering And Seakeeping Characteristics Of River Catamaran And Trimarana, Murdijanto Murdijanto, I Ketut Aria Pria Utama, Andi Jamaluddin

Makara Journal of Technology

The increase of fuel price has caused fleet operational and shipping business to be in danger situation. The fuel consumption of a ship is influenced by ship volume or wetted area which contributes directly to the increase of ship resistance and the size of main engine. In order to find out the appropriate answers, a series of investigation into river transportation using monohull, catamaran and trimaran types of vessel was carried out. The work focused on the estimation of total resistance and powering as well as seakeeping characteristics and carried out experimentally using tank test and numerically using a ship …

Determining The Standard Value Of The Oily Distortion Of Acquisition The Fingerprint Images, Rahmat Syam, Mochamad Hariadi, Mauridhi Hery Purnomo

Makara Journal of Technology

Determining the Standard Value of the Oily Distortion of Acquisition the Fingerprint Images. This research describes a novel procedure for determining the standard value of the oily distortion of acquisition the fingerprint images based on the score of clarity and ridge-valley thickness ratio. The fingerprint image is quantized into blocks size 32 x 32 pixels. Inside each block, an orientation line, which perpendicular to the ridge direction, is computed. The center of the block along the ridge direction, a two-dimension (2-D) vector V1 (slanted square) with the pixel size 32 x 13 pixels can be extracted and transformed to a …

Are Ieee 754 32-Bit And 64-Bit Binary Floating-Point Accurate Enough?, Bernaridho Hutabarat, I Ketut Eddy Purnama, Mochamad Hariadi, Mauridhi Hery Purnomo

Makara Journal of Technology

This paper describes a research toward the accuracy of floating-point values, and effort to reveal the real accuracy. The methods used in this research paper are assignment of values, assignment of value of arithmetic expressions, and output the values using floating-point value format that helps reveal the accuracy. The programming-tool used are Visual C# 9, Visual C++ 9, Java 5, and Visual BASIC 9. These tools run on top of Intel 80 x 86 hardware. The results show that 1*10-x cannot be accurately represented, and the approximate accuracy ranges only from 7 to 16 decimal digits.

Ergonomic Analysis Of Garment Industry Using Posture Evaluation Index (Pei) In Virtual Environment, Erlinda Muslim, Boy Nurtjahyo, Romadhani Ardi

Makara Journal of Technology

Ergonomic Analysis of Garment Industry using Posture Evaluation Index (PEI) in Virtual Environment. This research tried to study, in a virtual environment, the ergonomics of four divisions in garment industry: cutting division, sewing division, button division, and finishing division. Variables that influence the working conditions in each division are different; depend on the real situations that happened. The purpose is to assess the real working conditions based on ergonomics study using Posture Evaluation Index (PEI). PEI integrates the scores of low back analysis (LBA), ovako working posture (OWAS), and rapid upper limb assessment (RULA). Analysis phase was done using digital …

Formation Of Caco3 Particle And Conductivity Of Na2co3 And Cacl2 Solution Under Magnetic Field On Dynamic Fluid System, Nelson Saksono, Setijo Bismo, Roekmijati Widaningroem, Azwar Manaf

Makara Journal of Technology

Hard water causes the CaCO3 scale formation on the pipe walls and heat exchanger equipments in industrial or domestic water processes. A great number of experimental researches on the prevention of the CaCO3 precipitation process by magnetic field have been carried out. In this research, Na2CO3 and CaCl2 solutions was magnetized in the circulated flow condition (dynamic fluid system). The velocity of fluid and the circulation time was modified to examine its influences to the magnetization process. CaCO3 content was measured by titration method of EDTA complexometry. Conductivity test was conducted to find out hydrate ion bonding. The results showed …

Two-Class Classification With Various Characteristics Based On Kernel Principal Component Analysis And Support Vector Machines, Ivanna Kristianti Timotius, Iwan Setyawan, Andreas Ardian Febrianto

Makara Journal of Technology

Two class pattern classification problems appeared in many applications. In some applications, the characteristic of the members in a class is dissimilar. This paper proposed a classification system for this problem. The proposed system was developed based on the combination of kernel principal component analysis (KPCA) and support vector machines (SVMs). This system has been implemented in a two class face recognition problem. The average of the classification rate in this face image classification is 82.5%.

Calcium Wire Ladle Treatment To Improve Cleanliness Of Centrifugal Cast Steel, Edith Yolanda Martinez Silva

Masters Theses

"Centrifugal casting provides the opportunity of combining large centrifugal forces and directional solidification to reduce non-metallic inclusions in the cast steel product. Calcium treatment in the ladle has the potential of reducing and modifying non-metallic inclusions to achieve better machinability and mechanical properties. The objective of this research is to analyze the combined effects of calcium wire ladle treatment and centrifugal casting on the number, size, composition and morphology of non-metallic inclusions in centrifugally cast steel products.

All experiments were completed at an industrial foundry. The experiments involved feeding calcium wire into the ladle after argon oxygen decarburization (AOD) and …

Crack Formation In Investment Casting Ceramic Shells, W. A. Everhart

Masters Theses

"This thesis is a collection of papers that discuss shell cracking in investment casting during pattern removal. The application of rigid polymeric foam for large investment casting patterns with complex geometries can improve the dimensional tolerances and the surface quality of the casting. However, these pattern materials have a tendency to promote crack formation in investment casting shells during pattern removal by firing.

The first two papers discuss the factors affecting shell cracking and methods to prevent it. Experimental methods were combined with finite element modeling to predict stress in the shell. A 3D nonlinear finite element model was developed …

A Study On The Combined Effect Of Forging And Aging In Mg-Y-Re Alloy, S. K. Panigrahi, W. Yuan, R. S. Mishra, R. Delorme, B. Davis, R. A. Howell, K. Cho

Materials Science and Engineering Faculty Research & Creative Works

The combined effect of forging and aging on microstructural evolution and mechanical properties of a Mg-Y-RE alloy was studied in the present work by employing hardness measurements, tensile tests, optical microscopy (OM), scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD) analysis. the -F temper treated bulk Mg-Y-RE alloy samples were subjected to forging for microstructural refinement and subsequent aging to maximize the strength-ductility combination. the forged samples combined with peak aging treatment (60 h at 180 °C) exhibited an excellent combination of high strength (388 MPa) and high ductility (23%). the combined effect of grain refinement, work hardening, …

A Stress-Strain Model For A Two-Phase Ultrafine-Grained Aluminum Alloy, P. S. De, J. Q. Su, R. S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Two-phase ultrafine-grained (UFG) aluminum alloys with different precipitate and low-angle boundary distributions were examined for their monotonic stress-strain behavior. Precipitates in combination with low-angle grain boundaries were found to determine the deformation micro mechanism. It is proposed that thermally activated vacancy movement plays a central role in this regard. the experimental stress-strain curves matched well with the trend predicted by a modified Blum-Zheng model based on vacancy-assisted dislocation annihilation mechanism. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Friction Stir Lap Welded Advanced High Strength Steels: Microstructure And Mechanical Properties, M. Ghosh, K. Kumar, R. S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Friction stir welding was carried out under different heat input and cooling rates to produce lap joints between high strength martensitic steel sheets. the microstructure of the welds was characterized, and microhardness was evaluated. Joint efficiency was determined by lap shear test. Variation in processing conditions governed total heat input, peak temperature and cooling rate during friction stir welding. Weld nugget microstructure depended principally on cooling rate. the slowest cooling rate promoted ferrite-pearlite and the fastest cooling rate resulted in martensite formation in the weld nugget. the weakest region of all the joints was the heat affected zone, which consists …

Alloy Dissolution In Argon Stirred Steel, Darryl S. Webber

Doctoral Dissertations

"Alloying is required for the production of all steel products from small castings to large beams. Addition of large quantities of bulk alloys can result in alloy segregation and inconsistent alloy recovery. The objective of this research was to better understand alloy dissolution in liquid steel especially as it relates to Missouri S&Ts' patented continuous steelmaking process. A 45-kilogram capacity ladle with a single porous plug was used to evaluate the effect of four experimental factors on alloy dissolution: alloy species, alloy size or form, argon flow rate, and furnace tap temperature. Four alloys were tested experimentally including Class I …