Materials Science and Engineering Commons^™

Isothermal Aging Of Al-Ni-Sc Alloy Containing Al3ni Microfibers And Al3sc Nanoprecipitates, C Suwanpreecha, J P. Toinin, P Pandee, D C. Dunand, C Limmaneevichitr

Journal of Metals, Materials and Minerals

Binary Al-Sc alloys have excellent strength at room and elevated temperature up to 300°C due to coherent of Al3Sc nanoprecipitates. Binary Al-Ni alloys are an alternative alloy for high-temperature applications owing to high-thermal stability of Al3Ni microfibers. In this study, the hardness evolution at 300°C for up to 672 h for eutectic ternary Al-6Ni-0.4Sc (wt%) was studied and compared with binary Al-0.4Sc and Al-6Ni alloys. The Al-6Ni alloy maintains a constant hardness after aging at 300°C up to 672 h. Both Al-0.4Sc and Al-6Ni-0.4Sc alloys show strong precipitation strengthening response, with peak hardness reached after about 3 h aging, due …

Evaluating The Grinding Process Of Granites Using The Physico-Mechanical And Mineralogical Properties, S Kahraman, M Ucurum, E Yogurtcuoglu, M Fener

Journal of Metals, Materials and Minerals

Granitic rocks are sometimes ground for different purposes. Predicting the mean particle size (d50) is useful for planning and cost estimation of purposes. In order to investigate the possibility of predicting the d50 of ground rock from the physico-mechanical rock properties, six different granites were tested in the laboratory. First, the d50 values were correlated with the corresponding physico-mechanical properties. The simple regression analysis showed that there were no good correlations between the d50 and the physico-mechanical properties. Then, the multiple regression analysis was carried out and strong prediction equations were developed. It was also shown that the dominant parameter …

Optical And Luminescence Investigation Of Er3+ Doped In Na2o-Al2o3-P2o5 Glasses For Photonics Material Application, N Chanthima, N Kiwsakunkran, J Kaewkhao, N Sangwaranatee

Journal of Metals, Materials and Minerals

Optical and photoluminescence properties of Er3+ doped Na2O-Al2O3-P2O5 (NAPEr) glasses were prepared by conventional melt quenching technique at 1200°C. The absorption spectra have 11 peaks corresponded to 4I15/2 ground state to various excited energy levels. The absorption band at 1537 nm shows highest intensity in near-infrared (NIR) region. Also, it can be observed that the intensity of absorption bands increased on increase in concentrations of Er2O3. The Judd-Ofelt (JO) parameters (Ωλ, λ = 2, 4, and 6) are calculated using the absorption bands of the Er2O3 doped glass compositions. McCumber theory has been applied to determine the emission cross-sections (σe) …

Multifunctional Lightweight Aggregate Containing Phase Change Material And Water For Damage Mitigation Of Concrete, Wenyu Liao, Aditya Kumar, Kamal Khayat, Hongyan Ma

Materials Science and Engineering Faculty Research & Creative Works

This paper presents an innovative concept of multifunctional lightweight aggregate, which is produced by loading phase change material (PCM) into the interior of lightweight sand (LWS) and sealing the surface pores using water. The PCM loaded in the LWS functionalizes it as a temperature management agent in concrete, and the water in surface pores enables internal curing. It has been found that the particle shape and pore structure of crushed expanded shale LWS makes it an ideal carrier for PCM, loading sufficient PCM and maintaining better (compared to natural sand) mechanical interlocking. When coupled with the internal curing effect, the …

Nanothermomechanical Logic Gates For Thermal Computing, Ahmed Hamed

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

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications require the development of alternative computing technologies. Thermal computing, data processing based on heat instead of electricity, is proposed as a practical alternative and opens a new scientific area at the interface between thermal and computational sciences.

We successfully developed thermal AND, OR and NOT logic gates, achieved through the coupling between near-field thermal radiation and MEMS thermal actuation. In the process, we developed two novel non-linear thermal …

Magnetic Properties Of Nd–Fe–B Permanent Magnets Under Thermal Experimentation, Géraldine Houis

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

Neodymium-Iron-Boron (Nd-Fe-B) magnets were developed in the 1980s, and since then, they have appeared as a common component in many fields. From the industry to consumers or defense applications, from turbines, computers, cellphones to most audio systems, Nd-Fe-B magnets are present everywhere. But when Nd-Fe-B magnets are applied to the motors of electric vehicles and wind-turbine generators, their temperature rises, therefore Nd-Fe-B-Dy magnets are used. However, while the use of these magnets is common at low temperatures, their properties decrease dramatically with the increase of temperature. In this paper, the Nd-Fe-B-based samples used were prepared by using arc melting, melt …

Studies Of Initial Growth Of Gan On Inn, Alaa Alnami

Graduate Theses and Dissertations

III-nitride materials have recently attracted much attention for applications in both the microelectronics and optoelectronics. For optoelectronic devices, III-nitride materials with tunable energy band gaps can be used as the active region of devices to enhance the absorption or emission. A such material is indium nitride (InN), which along with gallium nitride (GaN) and aluminum nitride (AlN) embody the very real promise of forming the basis of a broad spectrum, a high efficiency solar cell. One of the remaining complications in incorporating InN into a solar cell design is the effects of the high temperature growth of the GaN crystal …

Study Of Amorphous Boron Carbide And Hydrogenated Boron Carbide Materials Using Molecular Dynamics And Hybrid Reverse Monte Carlo, Rajan Khadka

Graduate Theses/Dissertations

We present a computational study of amorphous boron carbide (a-B_xC) models using Molecular Dynamics (MD) studied with Stillinger-Weber (SW) and ReaxFF potential. The atomic structure factor (S(Q)), radial distribution function (RDF) and bond lengths comparison with other experimental and ab initio models shows that a random arrangement of icosahedra (B₁₂, B₁₁C) interconnected by chains (CCC, CBC) are present in a-B_xC. Afterward, Hybrid Reverse Monte Carlo (HRMC) technique is used to recreate a-B_xC structures. The existing SW potential parameters of Boron are optimized for the α-rhombohedral (Icosahedral B_{12 …}

Deep Donors And Acceptors In Β-Ga2O3 Crystals: Determination Of The Fe2+/3+ Level By A Noncontact Method, Christopher A. Lenyk, Timothy D. Gustafson, Larry E. Halliburton, Nancy C. Giles

Faculty Publications

Electron paramagnetic resonance (EPR), infrared absorption, and thermoluminescence (TL) are used to determine the Fe^2+/3+ level in Fe-doped β-Ga₂O₃ crystals. With these noncontact spectroscopy methods, a value of 0.84 ± 0.05 eV below the conduction band is obtained for this level. Our results clearly establish that the E2 level observed in deep level transient spectroscopy (DLTS) experiments is due to the thermal release of electrons from Fe²⁺ ions. The crystals used in this investigation were grown by the Czochralski method and contained large concentrations of Fe acceptors and Ir donors, and trace amounts of Cr …

Graphene/Polypropylene Nanocomposites, Carmen Karam Abuoudah

Theses

Graphene has been regarded as a multifunctional nanofiller for manufacturing polymer nanocomposites. A small amount of graphene nanosheets is expected to significantly improve the properties of base polymers. The property enhancement, however, is a function of the degree of exfoliation and dispersion of graphene as well as its compatibility with the polymer. The non-polar nature of polyolefins such as polyethylene (PE) and polypropylene (PP) restricts the homogeneous dispersion of graphene, leading to significant agglomeration of the nanosheets and thus, limiting the expected property improvements in polyolefins. Currently, more efforts are focused on finding strategies to improve graphene dispersion in polyolefins. …

The Flame Characteristics Of Diesel Fuel Blend With Kepuh (Sterculia Foetida) Biodiesel, Dani Hari Tunggal Prasetiyo, Nasrul Ilminnafik, Salahuddin Junus

Journal of Mechanical Engineering Science and Technology (JMEST)

Kepuh biodiesel fuel (sterculia foetida) is an alternative fuel that can be used to replace fossil fuel. Diesel fuel is performed to determine the laminar burning velocity and high flame by adding biodiesel kepuh volume of 10%, 20%, 30%. The purpose of this study was to study the effect of biodiesel and the effect of bunsen burners on the laminar burning velocity and flame height. Bunsen burner is made of copper and stainless steel. Testing of flame characteristics was carried out by heating the mixture of fuel and air at a temperature of 200°C. The purpose of heating the air …

Critical Solid Fraction Point Analysis: Case Study On Cement Mill Machine Diaphragm, Mochamad Achyarsyah, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

During the solidification process, metal liquids turn into solid geometry units including the riser and gating system. The disruption in the liquid flow often causes shrinkage in the object. Critical Solid Fraction Point is a critical point where the continuous liquid supply turned solid and unable to pour to some sections. Simulation software can predict the critical solid fraction time of an object and the liquid supply behavior. The simulation helps the designer in the casting design. The application of low steel alloys in the cement industry, e.g., the Diaphragm, needs development to minimize the shrinkage. This research aimed to …

Characteristic Analysis Of Horizontal Axis Wind Turbine Using Airfoil Naca 4712, Bili Darnanto Susilo, Gaguk Jatisukamto, Nurkoyim Kustanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Wind energy has been developed and used as a source of electrical energy by converting wind energy into electrical energy using a generator. There are some wind turbine parameters that important for wind turbines design and model, includes the size of the rotor radius, airfoil selection, chord length, and pitch angle. The study aims to characterize the performance of a horizontal axis wind turbine using computational methods. The methods used a design and simulation of NACA 4412 and NACA 4712 airfoil using QBlade software using wind conditions in the region of Pancer, Jember. Results show that the maximum Cl value …

The Effect Of Chlorophyll Concentration From Papaya Leaves On The Performance Of Dye-Sensitized Solar Cell, Dede Rizali, Heru Suryanto, Sukarni Sukarni

Journal of Mechanical Engineering Science and Technology (JMEST)

Dye-Sensitized Solar Cell (DSSC) is the third generation solar cell that has sandwich structure consisted of organic dye material and other components such as titanium dioxide (TiO2) semiconductor, electrolyte, and substrates (counter electrode and working electrode). The dye in the device was made from green plant chlorophyll such as papaya. This research aimed to find the influence of dye concentration from papaya leaves chlorophyll on the performance of DSCC. The discussion covered the output power (Pout), Fill Factor (FF), and efficiency (ɳ). The method in this research was explorative experimental with independent variables such as direct and indirect sunlight. The …

Synthesis And Applications Of Hematite Α-Fe2o3 : A Review, Muhamad Muhajir, Poppy Puspitasari, Jeefferie Abdul Razak

Journal of Mechanical Engineering Science and Technology (JMEST)

This article reviewed the hematite α-Fe2O3. It focuses on its material properties, nanostructures, synthesis techniques, and its numerous applications. Researchers prepared the hematite nanostructure using the synthesis methods such as hydrothermal, and, further, enhanced it by improving the techniques to accommodate the best performance for specific applications and to explore new applications of hematite in humidity sensing.

Failure Analysis On Titen Proto-Xx Car Chassis, Gaguk Jatisukamto, Rika Dwi Hidayatul Qoryah, Santoso Mulyadi

Journal of Mechanical Engineering Science and Technology (JMEST)

The car chassis as a skeleton supports all loads and is the most important component. Car chassis requirements must be rigid, twisting resistant, vibration resistant and resistant to fatigue. This study aims to find the cause of the failure of the Titen Proto-XX car chassis connection. The research methodology was conducted by testing the composition of materials and structural analysis using Ansys Workbench Release 15.0 software. The conclusion of the research is that the skeletal structure material uses Aluminum AA series 1XXX with Al content greater than 99.5%, the welding ability is low, causing a failure in the welded joint. …

Towards Completely Automated Glycan Synthesis, Matteo Panza

Dissertations

Carbohydrates are ubiquitous both in nature as biologically active compounds and in medicine as pharmaceuticals. Although there has been continued interest in the synthesis of carbohydrates, chemical methods require specialized knowledge and hence remain cumbersome. The need for development of rapid, efficient and operationally simple procedures has come to the fore. This dissertation focuses on the development of a fully automated platform that will enable both experts and non-specialists to perform the synthesis of glycans. Existing automated methods for the synthesis of oligosaccharides are highly sophisticated, operationally complex, and require significant user know-how. By contrast, high performance liquid chromatography (HPLC) …

Additively Manufactured Continuous Carbon Fiber Thermoplastic Composites For High-Performance Applications, Nekoda Van De Werken

Mechanical Engineering ETDs

The goal of this dissertation is to provide a foundation for the advancement of additive manufacturing (AM) toward production of high-performance carbon fiber reinforced polymer matrix composites (CFRPs). AM can provide valuable advantages over conventional composite manufacturing techniques, including the control over fiber orientation, capability of manufacturing complex geometries, out-of-autoclave processing, elimination of the need for composite tooling, and the ability to perform lights-out manufacturing. Currently, however, a suite of challenges related to modelling, design, manufacturing defects, and general limitations in the current understanding of the processing-structure-property relationships exist in AM of composites. To this end, this dissertation investigates novel …

Molecular Dynamics Simulations Of Interaction Of Dna Nucleotides And Lignin Oligomers With Small Molecules And Interfaces, Xinjie Tong

LSU Doctoral Dissertations

Molecular dynamics (MD) simulations of interaction of DNA nucleotides with self-assembled monolayers (SAMs) provide valuable information that is critical to the development of a new DNA sequencing technique. We investigated the interactions and transport characteristics of mononucleotides moving through nanoslits with SAMs-covered surfaces. Our simulations focused on nanoslits in which the walls were composed of three different types of SAMs: methylformyl terminated, methyl terminated, and phenoxy terminated. The results demonstrated that the phenoxy terminated surfaces have the shortest required nanoslits length for nucleotides separation.

Using MD simulations, we also investigated the interaction of mono-lignin and oligo-lignols with lipid bilayers and …

The Application Of Gray-Scale Level-Set Method In Segmentation Of Concrete Deck Delamination Using Infrared Images, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Conventional nondestructive delamination detection of concrete pavements through thermography is often based on temperature contrasts between delaminated and sound areas. Non-uniform backgrounds caused by the environmental conditions are often challenging for contrast-based methods to robustly differentiate the delaminated areas from the sound areas. Instead of focusing on the temperature contrast, this study proposes a temperature gradient-based level set method (LSM) to detect boundaries for delamination segmentations. A modified edge indicator function is developed to represent the normalized temperature gradient of a thermal image. The experimental study was conducted to evaluate its applicability and stability for boundary detection in terms of …