Optimization And Characterization Of Novel Injection Molding Process For Metal Matrix Syntactic Foams,
2020
Missouri University of Science and Technology
Optimization And Characterization Of Novel Injection Molding Process For Metal Matrix Syntactic Foams, Myranda Spratt, Joseph William Newkirk
Materials Science and Engineering Faculty Research & Creative Works
Metal matrix syntactic foams are particulate composites comprised of hollow or porous particles embedded in a metal matrix. These composites are difficult to manufacture due primarily to the lightweight, relatively fragile filler material. In this work, an injection molding process was developed for metal matrix syntactic foams. First, an aqueous binder was optimized for low-pressure injection molding. A mixture model was used to optimize the composition of the binder to achieve the highest relative density. The model predicted the maximum relative density was at a binder composition (in vol.%) of 7% agar, 4% glycerin, and 89% water. Second, this binder …
Examination Of Early Stage Grey Iron Solidification Through The Development Of Fast-Quench Methodology,
2020
Georgia Southern University
Examination Of Early Stage Grey Iron Solidification Through The Development Of Fast-Quench Methodology, James C. Liggett
Honors College Theses
As grey iron casting accounts for a significant share of the foundry industry, proper understanding of the effects of solidification and growth mechanisms on the mechanical properties of grey iron is crucial. Prior experimentation has been performed examining early stage solidification and growth of the carbon phase of ductile iron, in which rapid quench samples are obtained which detail austenite-graphite interactions during solidification. This prior experimentation is built upon in though this research and applied to examine the early stage growth of flake graphite in grey iron. The purpose of this research is to validate a proposed fast-quench method by …
Effect Of Landfill Leachates On Some Water Quality Indicators Of Selected Surface Water And Groundwater At Ilokun, Ado-Ekiti, Nigeria,
2020
Federal University Oye-Ekiti, Oye-Are Road, Oye-Ekiti 371104, Nigeria
Effect Of Landfill Leachates On Some Water Quality Indicators Of Selected Surface Water And Groundwater At Ilokun, Ado-Ekiti, Nigeria, Olorunwa Omofunmi, Adesola Satimehin, Abraham Oloye, Okwunna Umego
Makara Journal of Technology
This study was conducted to examine the impact of dumpsites on the quality of groundwater and surface water. The water samples and leachates were collected from dumpsites in respective zones. The physicochemical properties of the samples were examined and determined in accordance with the standards of the American Public Health Association. Results indicated that the groundwater and surface water that are close to the dumpsites have an electrical conductivity of 385 and 245 Sd/cm, total dissolved solids of 168 and 128 mg/L, a turbidity of 4.6 and 22 NTU, a total alkalinity of 103 and 50 mg/L, a total hardness …
Microstrip Filters: A Review Of Different Filter Designs Used In Ultrawide Band Technology,
2020
Department of Electronics and Communication Engineering, Sir Padampat Singhania University, Udaipur 313601, India
Microstrip Filters: A Review Of Different Filter Designs Used In Ultrawide Band Technology, Hussain Bohra, Giriraj Prajapati
Makara Journal of Technology
In this study, optimization techniques applied in designing microstrip bandpass ultra-wideband (UWB) filters are presented. Optimization based on various defected ground structure techniques, resonator designs, and type of dielectric materials is discussed. Microstrip bandpass filters implemented at UWB frequency bands used in wireless communication systems have key features to control frequency response in passband and stopband. Optimization techniques are studied to attain optimum performance of bandpass microstrip filters to ensure minimum insertion loss, high selectivity, compactness, sharp transitions at cut-off frequencies, high return loss, and excellent linearity. Extensive study shows that proper selection of fabrication techniques and type of material …
Effect Of Catholyte Concentration On Current Production During Chocolate Industry Wastewater Treatment By A Microbial Fuel Cell,
2020
Research Unit of Clean Technology, Indonesian Institute of Sciences (LIPI), Bandung 40135, Indonesia
Effect Of Catholyte Concentration On Current Production During Chocolate Industry Wastewater Treatment By A Microbial Fuel Cell, Diana Rahayuning Wulan, Suprihanto Notodarmojo
Makara Journal of Technology
Microbial fuel cells (MFCs) use bacteria as a catalyst to oxidize organic and/or inorganic substrates and produce electric currents. Wastewater could function as an electron donor in the anode chamber and, thus, represents a very promising energy source. Catholytes, as electron acceptors, influence power production in MFCs by increasing the availability of electrons. The present research aims to determine the influence of catholyte concentration on current production in an aerobic two-chamber MFC. Aerobic treatment was carried out in the two-chamber MFC operated in an incubator at 37 1 °C with and without aeration in the cathode chamber. Wastewater from …
Evaluation Of Il-17a And Il-17f Gene Expression In Peripheral Blood Mononuclear Cells In Different Clinical Stages Of Chronic Hepatitis B Infection In An Iranian Population,
2020
Faculty of Biological Sciences, Islamic Azad University, Tehran-North Branch, Tehran 1651153311, Iran
Evaluation Of Il-17a And Il-17f Gene Expression In Peripheral Blood Mononuclear Cells In Different Clinical Stages Of Chronic Hepatitis B Infection In An Iranian Population, Tannaz Akbari Kolagar, Seyed Reza Mohebbi, Fatemeh Ashrafi, Shahrzad Shoraka, Hamid Asadzadeh Aghdaei, Mohammad Reza Zali
Makara Journal of Technology
Hepatitis B virus (HBV) infection is one of the main causes of liver damage, which can also lead to chronic hepatitis B (CHB) infection. More than 240 million individuals worldwide are chronic carriers of HBV. Among individuals with CHB who are untreated, approximately 15% – 40% will progress to liver cirrhosis or cancer. The interactions between HBV and host immune response play significant roles in the progression of CHB. CHB can be generally divided into four different clinical phases: immune tolerance (IT), immune clearance, inactive carrier, and Hepatitis B surface antigen (HBsAg)-negative reactivation phase (ENEG). Many studies showed that interleukins …
Redesign Of Product Packaging With Kansei Engineering: Empirical Study On Small-Medium Enterprises In Indonesia,
2020
Department of Industrial Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424, Jawa Barat
Redesign Of Product Packaging With Kansei Engineering: Empirical Study On Small-Medium Enterprises In Indonesia, Amalia Suzianti, A. Aldianto
Makara Journal of Technology
Small-medium enterprises (SMEs) in Indonesia have been proven to be one of the important pillars of the national economy. Unfortunately, some problems hinder their development, and one of the critical problems is the quality of product packaging. The packages of SME products are considered poor, dirty, and unattractive. Packaging problem is one of the factors why consumers are less interested in buying and why SME products always lose in the competition with other products. This study discusses how to employ Kansei engineering to design better SME product packaging with a focus on psychological (affective) aspects. This research concludes that there …
Effect Of Pvdf-Ca Ratio On Electrospun Membrane For Water–Oil Filtration Application,
2020
Nanostructured Renewable Energy Materials Laboratory, Universiti Malaysia Pahang, Pahang 26300, Malaysia
Effect Of Pvdf-Ca Ratio On Electrospun Membrane For Water–Oil Filtration Application, Mohamad Haziq Alias, Izan Izwan Misnon, Rajan Jose
Makara Journal of Technology
Oil spillage and generation of industrial water–oil wastewater mixture ignite a focus on filtration technology. Electrospinning technique provides a versatile route in producing tunable diameter and pores in nanofiber filtration membrane development. In this work, polyvinylidene difluoride (PVDF) and cellulose acetate (CA) electrospun membrane at different concentration ratios were synthesized for water–oil filtration application. The polymeric solutions were characterized using viscometer and conductivity testing, whereas the membranes were analyzed using contact angle, tensile test, scanning electron microscopy (SEM), and filtration testing of oil (dichloromethane). Conductivity test showed a decreased conductivity along with decrement of CA ratio in the polymeric solution. …
Performance-Shaping Factors Of Personnel Performing Evacuation And Escape On Offshore Installations In Tropical,
2020
Centre of Hydrogen Energy, Institute of Future Energy, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
Performance-Shaping Factors Of Personnel Performing Evacuation And Escape On Offshore Installations In Tropical, Norafneeza Norazahar, Nur Azizah Arryanie Morshidi, Arshad Ahmad, Wijayanuddin Mohd Ali
Makara Journal of Technology
Performance-shaping factors (PSFs) are used to address the strengths and weaknesses of workers performing escape and evacuation activities. These PSFs are time, environmental factors as stressors, complexity of activities, experiences and training, interaction between workers and emergency equipment, workers’ physical conditions, and procedures. This paper presents a survey work on fitness for the duty of workers performing basic offshore survival and emergency response training. The training provides credible scenarios of escape and evacuation in case of an emergency of offshore installations in tropical waters. The survey is conducted among participants of the tropical basic offshore safety induction & emergency training …
On The Recovery And Fatigue Life Extension Of Stainless Steel 316 Metals By Means Of Recovery Heat Treatment,
2020
Louisiana State Univ, Dept Mech & Ind Engn, Baton Rouge, LA 70803 USA
On The Recovery And Fatigue Life Extension Of Stainless Steel 316 Metals By Means Of Recovery Heat Treatment, Ali Haghshenas, M. M. Khonsari
Faculty Publications
In this paper, we propose a methodology for enhancing the fatigue life of SS316 by performing intermittent recovery heat-treatment (RHT) in the Argon environment at different temperatures. To this end, fully-reversed fatigue bending tests are conducted on the heat-treated SS316 specimens. Damping values are obtained using the impact excitation technique to assess the damage remaining in the material after each RHT and the corresponding fatigue life. Damping is also used to distinguish the three stages of the fatigue phenomenon and the onset of crack initiation. The results show that by performing intermittent RHTs, the density of dislocation is decreased substantially …
Microstructural Influence On Mechanical Properties Of A Lightweight Ultrahigh Strength Fe-18mn-10al-0.9c-5ni (Wt%) Steel,
2020
Missouri University of Science and Technology
Microstructural Influence On Mechanical Properties Of A Lightweight Ultrahigh Strength Fe-18mn-10al-0.9c-5ni (Wt%) Steel, Michael Piston, Laura Bartlett, Krista R. Limmer, Daniel M. Field
Materials Science and Engineering Faculty Research & Creative Works
This study evaluates the role of thermomechanical processing and heat treatment on the microstructure and mechanical properties of a hot rolled, annealed, and aged Fe-18Mn-10Al-0.9C-5Ni (wt%) steel. The steel exhibited rapid age hardening kinetics when aged in the temperature range of 500-600 ⁰C for up to 50 h, which has been shown in other work to be the result of B2 ordering in the ferrite and K-carbide precipitation within the austenite matrix. The ultimate tensile strength increased from 1120 MPa in the annealed condition to 1230 MPa after 2 h of aging at 570 ⁰C. Charpy V-notch toughness was evaluated …
Peritectic Behavior Detection In The Fe-C-Mn-Al-Si Steel System Using Fiber Optic Temperature Mapping,
2020
Missouri University of Science and Technology
Peritectic Behavior Detection In The Fe-C-Mn-Al-Si Steel System Using Fiber Optic Temperature Mapping, Muhammad Roman, Damilola Balogun, Rex E. Gerald Ii, Laura Bartlett, Jie Huang, Ronald J. O'Malley
Materials Science and Engineering Faculty Research & Creative Works
Peritectic reactions can cause surface defects and breakouts in continuous casting and the peritectic region is often avoided by adjusting the chemical composition of the steel to cast outside of the peritectic sensitivity range. However, the combined effects of C, Mn, Al, and Si on the boundaries that map peritectic region are still disputed for many advanced high strength steel grades. An apparatus for performing controlled solidification experiments is being developed to characterize the effects of chemical composition on the uniformity of shell growth during solidification using a copper chill mold with an embedded fiber-optic temperature sensor that enables high …
A Modified Johnson-Cook Model Incorporating The Effect Of Grain Size On Flow Stress,
2020
Missouri University of Science and Technology
A Modified Johnson-Cook Model Incorporating The Effect Of Grain Size On Flow Stress, S. Ganguly, Mario F. Buchely, K. Chandrashekhara, Semen Naumovich Lekakh, Ronald J. O'Malley
Materials Science and Engineering Faculty Research & Creative Works
The mechanical properties of steel are influenced by grain size, which can change through mechanisms such as nucleation and growth at elevated temperatures. However, the classic Johnson-Cook model that is widely used in hot deformation simulations does not consider the effect of grain size on flow stress. In this study, the Johnson-Cook model was modified to incorporate the effects of austenite grain size on flow stress. A finite element model was employed to characterize the effects of grain size on the flow stress for different steel grades over a range of temperatures (900⁰ to 1300⁰). Simulation results show good agreement …
Interactions Between Dry Vibratable Tundish Linings And Steel Melts,
2020
Missouri University of Science and Technology
Interactions Between Dry Vibratable Tundish Linings And Steel Melts, Tyler M. Richards, Ronald J. O'Malley, Jeffrey D. Smith, Todd P. Sander
Materials Science and Engineering Faculty Research & Creative Works
Interactions between two tundish working linings and molten steel were investigated using industrial samples and laboratory testing. Periclase-based dry vibe linings from two production facilities were sampled and examined after casting: one containing 30 wt.% olivine and one without olivine. Cathodoluminescence imaging, secondary electron microscopy, energydispersive spectroscopy and x-ray diffraction analysis were performed to characterize the interactions. An experiment was developed to replicate the conditions found in a production tundish on the laboratory scale. Results comparing interactions observed in laboratory lining tests and commercial lining samples for the two lining materials are presented and discussed.
Scale Formation On 430 Stainless Steel In A Simulated Slab Combustion Reheat Furnace Atmosphere,
2020
Missouri University of Science and Technology
Scale Formation On 430 Stainless Steel In A Simulated Slab Combustion Reheat Furnace Atmosphere, Richard Osei, Semen Naumovich Lekakh, Ronald J. O'Malley
Materials Science and Engineering Faculty Research & Creative Works
Scale formed during slab reheating can be difficult to remove by high-pressure descaling, having a negative impact hot roll surface quality. A large-capacity thermogravimetric apparatus that replicates the combustion atmosphere and temperature in a slab reheat furnace was used to investigate scale formation on 430 stainless steel. Effects of reheating parameters (temperature, time and atmosphere) on oxidation kinetics were investigated. Oxidized samples were characterized by scanning electron microscopy, Raman spectroscopy and x-ray diffraction to document the microstructure and morphology of scale. Mechanisms for the formation of multi-layered oxide structures that complicate oxidation kinetics and scale removal are discussed.
New Experimental Apparatus To Investigate Hot Tearing Behavior In Steel,
2020
Missouri University of Science and Technology
New Experimental Apparatus To Investigate Hot Tearing Behavior In Steel, Yanru Lu, Laura Bartlett, Ronald J. O'Malley, Semen Naumovich Lekakh, Mario F. Buchely
Materials Science and Engineering Faculty Research & Creative Works
Hot tearing is a complex thermomechanical phenomenon occurring in the semi-solid region. Strain in this region can induce cracking and localized alloying element segregation. An apparatus for investigating hot tearing was developed utilizing a servo-motor controlled cylinder to apply a pre-determined amount of strain to the solidifying shell. A special mold was developed using filling and solidification modeling to ensure that dendrite growth was perpendicular to applied strain. A computer-automated system was utilized to control the strain and strain rate and measure the force and displacement. Solidification experiments utilizing AISI 1020 steel validated the apparatus capabilities and optimized testing parameters.
The Influence Of Ti, Nb And V On The Hot Ductility Of As-Cast Microalloyed Steels,
2020
Missouri University of Science and Technology
The Influence Of Ti, Nb And V On The Hot Ductility Of As-Cast Microalloyed Steels, Madhuri Varadarajan, Laura Bartlett, Ronald J. O'Malley, Semen Naumovich Lekakh
Materials Science and Engineering Faculty Research & Creative Works
Microalloying with Ti, Nb and V, both individually and in combination, is a common method for producing steels with high strength and toughness. However, interaction with other elements and impurities can lead to cracking during continuous casting and rolling. The hot ductility of commercially cast V, Nb and Nb-V-Ti steels has been investigated using two experimental methods: tensile testing utilizing a servo-hydraulic load frame with a resistance furnace and thermomechanical testing using rapid joule heating. The temperature-dependent ductility of these steels is compared for both test methods. Factors that influence the ductility of these steels are discussed.
Processing And Properties Of Medium-Mn Trip Steel To Obtain A Two-Stage Trip Behavior,
2020
Missouri University of Science and Technology
Processing And Properties Of Medium-Mn Trip Steel To Obtain A Two-Stage Trip Behavior, D. M. Field, L. G. Garza-Martinez, D. C. Van Aken
Materials Science and Engineering Faculty Research & Creative Works
Two medium-Mn steels of nominal composition 0.15C-2.0Si-10.5Mn-(0.75, 1.5) Al-0.04Nb-balFe (wt pct) were processed to produce sub-micron grain sizes of 0.65 and 0.80 μm. Mechanical testing was performed in three successive conditions: hot rolled, intercritically annealed, and cold rolled with subsequent intercritical annealing. Intercritical annealing was performed at 923 K for 20 hours. Electron-backscattered diffraction and X-ray diffraction were utilized to characterize the microstructure, consisting of α-ferrite, α-martensite, ε-martensite, and γ-austenite. Microstructural constituents were tracked during tensile deformation, and it was found that both steels exhibited two-stage TRIP with γ-austenite martensitically transforming first to ε-martensite and as strain increased ε-martensite transformed …
Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination,
2020
Teknik Mesin, Sekolah Tinggi Teknologi Ronggolawe, Jawa Tengah 58315, Indonesia
Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination, Agus Dwi Korawan
Makara Journal of Technology
The melting of a phase change material (PCM) in a cavity with a gradient of hot wall inclination was simulated numerically using five models, namely, Model-A, Model-B, Model-C, Model-D, and Model-E with gradients of −2, −4, ∞, 4, and 2, respectively. The PCM was paraffin wax, which was melted using an enthalpy porosity technique with a pressure-based method. Model-A was found to be the best model. For the completion of the melting process, the models were assigned with the liquid fraction of 1. Model-A required the shortest time, followed by Model-B, Model-C, Model-E, and Model-D, respectively. Compared with Model-C, Model-A …
Material Design, Processing, And Engineering Requirements For Magnetic Shape Memory Devices,
2020
Boise State University
Material Design, Processing, And Engineering Requirements For Magnetic Shape Memory Devices, Andrew Armstrong
Boise State University Theses and Dissertations
For magnetic shape memory (MSM) alloys, a magnetic field stimulates a shape change. We use the shape change to build devices such as micro-actuators, sensors, and microfluidic pumps. Currently, (as a novel technology,) devices suffer from some material and magnetic driver shortcomings. Here we address the issues related to operating temperature, repeatability, failure, and magnetic driver development. To increase the operating temperature of the MSM material, we alloyed Fe and Cu to Ni-Mn-Ga. We showed that the element-specific contribution to the valence electron density as parameter systematically determines the effect of each element on the variation of the martensite transformation …
