Materials Science and Engineering Commons^™

Surface And Interface Characterization Of Solution-Processed Metal Oxides And Pedot:Pss Using Photoelectron Spectroscopy, Lynette M. Kogler

UNLV Theses, Dissertations, Professional Papers, and Capstones

Solution-processed materials are appealing for use in printable electronics as a means to lower production costs, but precise control of the process is crucial for achieving the desired properties in the final materials and their interfaces. Electronic interface properties depend on both the involved materials and their fabrication processes, impacting the development and commercialization of these materials. Analyzing the chemical and electronic structure of these materials, particularly at the surfaces and interfaces, is important not only for insuring that the materials have the desired properties, but also for understanding the effects of the fabrication process and how to modify properties …

Design, Analysis, And Application Of A Cellular Material/Structure Model For Metal Based Additive Manufacturing Process., Shanshan Zhang

Electronic Theses and Dissertations

Powder bed fusion additive manufacturing (PBF-AM) has been broadly utilized to fabricate lightweight cellular structures, which have promising potentials in many engineering applications such as biomedical prosthesis, aerospace, and architectural structures due to their high performance-to-weight ratios and unique property tailorabilities. To date, there is still a lack of adequate understanding of how the cellular materials are influenced by both the geometry designs and process parameters, which significantly hinders the effective design of cellular structures fabricated by PBF-AM for critical applications. This study aims to demonstrate a cellular structure design methodology that integrates geometrical design and process-material property designs. Utilizing …

Material Properties Design Using Simulations And Experiments For Powder Injection Molding Of Lead Zirconate Titanate (Pzt)., Bhushan Pramod Bandiwadekar

Electronic Theses and Dissertations

Powder injection molding (PIM) process simulations can be performed to minimize the number of injection molding experiments by estimating material properties necessary for PIM simulations. In current work, lead zirconate titanate (PZT) powder-polymer binder feedstock was compounded for 45 vol. % and 52 vol. % solids loading. PIM experiments on designed micro-pillar array geometry were performed using 52 vol. % PZT. Using PIM experiments results as basis, PIM simulations were performed on designed micro-pillar array geometries to understand the effectiveness of PIM simulations with the use of estimated feedstock properties in predicting molding behavior that have micro-features. Additionally, PIM simulations …

A Study Of Manganese And Cobalt Incorporated Nickel Oxide Based Core-Shell Magnetic Nanoparticles, Samiul Hasan

Graduate Theses/Dissertations

The synthesis along with the structural and magnetic properties of manganese (Mn) and cobalt (Co) -incorporated nickel oxide (NiO) inverted core-shell nanoparticles (CSNs) were investigated. The primary objective of this study was to determine the effect of substitution of nickel (Ni) by transition metal ions (Mn²⁺/Co²⁺) in affecting the magnetic properties of the resultant CSNs. The core of the CSNs is comprised of NiO and the shell constitutes a Ni_x(Mn/Co)_1-xO phase. The synthesis of the CSNs was accomplished in two steps: first, NiO nanoparticles were synthesized using a thermal decomposition method. In …

Structural And Elastic Properties Of Degenerate Sno Monolayers At Finite Temperature, Afsana Sharmin

Graduate Theses and Dissertations

Chalcogen-based layered superconductors with a litharge structure such as FeS and FeSe mono-layers undergo structural and superconducting phase transitions that are tunable by doping. Representing another material platform with a litharge structure but without valence d-electrons, SnO monolayers also display a structural ground state with a degenerate rectangular unit cell at zero temperature and a charge-tunable energy barrier that leads to a thermally-controllable structural phase change. Doped SnO monolayers with rectangular degenerate unit cells give rise to two-dimensional multiferroicity. Their two-dimensional elastic energy landscape adopts a basic analytic expression that is employed to discuss this structural transition. The results contained …

Modeling And Simulation Of Iii-Nitride-Based Solar Cells Using Nextnano®, Malak Refaei

Graduate Theses and Dissertations

Nextnano³ software is a well-known package for simulating semiconductor band-structures at the nanoscale and predicting the general electronic structure. In this work, it is further demonstrated as a viable tool for the simulation of III-nitride solar cells. In order to prove this feasibility, the generally accepted solar cell simulation package, PC1D, was chosen for comparison. To critique the results from both PC1D and Nextnano3, the fundamental drift-diffusion equations were used to calculate the performance of a simple p-n homojunction solar cell device analytically. Silicon was picked as the material for this comparison between the outputs of the two simulators as …

Generalized Ellipsometry On Complex Nanostructures And Low-Symmetry Materials, Alyssa Mock

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, complex anisotropic materials are investigated and characterized by generalized ellipsometry. In recent years, anisotropic materials have gained considerable interest for novel applications in electronic and optoelectronic devices, mostly due to unique properties that originate from reduced crystal symmetry. Examples include white solid-state lighting devices which have become ubiquitous just recently, and the emergence of high-power, high-voltage electronic transistors and switches in all-electric vehicles. The incorporation of single crystalline material with low crystal symmetry into novel device structures requires reconsideration of existing optical characterization approaches. Here, the generalized ellipsometry concept is extended to include applications for materials with …

Studies On Stable Crack Growth, Mohammed Juma Humaid Al-Ghafri

Theses

The goal of this work is to experimentally investigate the stable crack growth (SCG) fracture behavior of AISI 4340 alloy steel. A series of mode I and mixed mode SCG fracture tests were carried out on 8 mm thick compact tension (CT) specimens subjected to quasistatic loading. The wire cutting technique was used to introduce a pre-notch/ pre-crack of 0.05 mm root radius to the specimen. Five different loading angles Ψ between the loading axis and the crack surface were employed; 90° (mode I), 75°, 65°, 60° and 50°. Five different ratios of original crack length to specimen width a …

Effects Of The Internal Magnetic Field On The Magneto-Mechanical Properties Of Magnetic Shape Memory Alloys, Anthony Hobza

Boise State University Theses and Dissertations

Shape memory alloys are a class of functional material which recover from large strains without permanent deformation. The strain is accommodated by the displacement of twin boundaries in the martensite phase. The shape memory alloy Ni-Mn-Ga is also ferromagnetic. Ni-Mn-Ga preferentially magnetizes along a certain crystallographic axis. This direction of easy magnetization changes across twin boundaries, such that the directions in neighboring twin domains are nearly perpendicular.

The interaction of magnetic moments and interfaces including the crystal surface and twin boundary interfaces has a large role in the magnetization process of the material. The goal of this study is to …

Thermodynamics And Kinetics Of Dna Origami Cross-Tile Array Formation, Brett Michael Ward

Boise State University Theses and Dissertations

As the cost to continue scaling photolithography to pattern smaller semiconducting devices increases exponentially, new materials and fabrication approaches are being sought to extend and enhance current capabilities. DNA nanostructures have been identified as a promising material for patterning nanoscale devices, and several studies have demonstrated the ability to program DNA nanostructures to self-assemble into large scale arrays. These DNA arrays can be designed to create the patterns necessary for fabricating semiconductor device features. However, these structures are far from ideal and contain a number of defects that limit the adoption of this approach for manufacturing. In order to create …

Development Of A Ferrite-Based Electromagnetic Wave Detector, Muhammad Hanis Bin Zakariah, Poppy Puspitasari, Nur Azliza Ahmad

Journal of Mechanical Engineering Science and Technology (JMEST)

Direct detection of hydrocarbon by an active source using electromagnetic (EM) wave termed Sea Bed Logging (SBL) has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges including sensitivity and lapsed time. Our initial response to this issue is to develop a ferrite-based EM wave detector for Sea Bed Logging (SBL). Ferrite bar and copper rings in various diameters were used as detector 1 (D1). For Detector 2 (D2), toroid added with copper wires in different lengths at the centre of it were used. The first experiment is to determine the inductance and resistance …

Formula Of Moulding Sand, Bentonite And Portland Cement To Improve The Quality Of Al-Si Cast Alloy, Andoko Andoko, Poppy Puspitasari, Avita Ayu Permanasari, Didin Zakaria Lubis

Journal of Mechanical Engineering Science and Technology (JMEST)

A binder is any material used to strengthen the bonding of moulding sand grains. The primary function of the binder is to hold the moulding sand and other materialstogether to produce high-quality casts. In this study, there were four binder compositions being tested, i.e. 5% bentonite + 5% Portland cement, 4% bentonite + 6% Portland cement, 6% bentonite + 4% Portland cement, and 7% bentonite + 3% Portland cement. Each specimen was measured for its compressive strength, shear strength, tensile strength and permeability. The highest compressive strength was obtained fromthe specimen composed of 6% bentonite+ 4% Portland cement. The highest …

Blanking Clearance And Punch Velocity Effects On The Sheared Edge Characteristic In Micro-Blanking Of Commercially Pure Copper Sheet, Didin Zakariya Lubis, Ichsan Ristiawan

Journal of Mechanical Engineering Science and Technology (JMEST)

This study aims to identify the influences between clearance and punch velocity on the part edge quality of blanked parts. Experiments have been conducted using material copper, punch-die clearance and punch velocity variations. In order to determine the reachable punch-die clearance and punch velocity required for blanking. The quality of the part-edge characteristics shows that higher punch velocity and decreases clearance value can improve the part-edge quality, resulting in smaller burr height and rollover, and a larger shear zone. Furthermore, it could be observed that the part-edge quality improvement when blanking with high punch velocity is much more distinct for …

Modeling Of Antenna For Deep Target Hydrocarbon Exploration, Nadeem Nasir, Noorhana Yahya, Hasnah Mohd Zaid, Afza Shafie, Norhisham Hamid

Journal of Mechanical Engineering Science and Technology (JMEST)

Nowadays control source electromagnetic method is used for offshore hydrocarbon exploration. Hydrocarbon detection in sea bed logging (SBL) is a very challenging task for deep target hydrocarbon reservoir. Response of electromagnetic (EM) field from marine environment is very low and it is very difficult to predict deep target reservoir below 2km from the sea floor. This work premise deals with modeling of new antenna for deep water deep target hydrocarbon exploration. Conventional and new EM antennas at 0.125Hz frequency are used in modeling for the detection of deep target hydrocarbon reservoir. The proposed area of the seabed model (40km ´ …

Properties Of Brass Under Different Pouring Temperatures In Sand Casting Process, Poppy Puspitasari, Avita Ayu Permanasari, Andoko Andoko, Bayu Angga Pratama

Journal of Mechanical Engineering Science and Technology (JMEST)

This study aimed to determine the toughness of casts produced by the sand casting process at various temperatures against brass, and to investigate the structure contained in the cast madeusing abrass metal mould. This study was experimental research that observed the results of a treatment applied to a specimen group. This pre-experimental study usedthe one-shot case study model in which a group of samples was given treatment. The results showed that the specimen poured at 900°C exhibiteda microstructure consisting ofgood Cu-Zn content, while that at 700°Chad the least Cu content. It indicates that the higher the temperature used for metal …

Compositional And Structural Evolution During Ball Milling Of Ti-Based Metallic Glass Powder, Yanuar Rohmat Aji Pradana

Journal of Mechanical Engineering Science and Technology (JMEST)

Ti42Zr40Ta3Si7.5Sn7.5metallic glass powder prepared for subsequent consolidation by hot pressing were produced by high energy ball milling from amorphous ribbon and both of the compositional and structural evolution on milled powders were studied using XRD and DSC analyses. By using WC vial and balls, the abrasion of milling media occurred causing WC contamination on < 105 µm milled powder after 2 cycles of milling. Based on DSC analysis, the contamination clearly reduced theΔTxof the alloy up to 48%. On the other hand, the contamination were overcome after milling using SS vial and balls, proved by no crystal peak observed on XRD pattern of all milling cycle levels. However, the thermal stability was noticed to be decreased implying the presence of nanocrystals on the amorphous powder after ball milling and the nanocrystal amount tend to be higher when more milling cycles were applied.

Thermogravimetric And Kinetic Analysis Of Cassava Starch Based Bioplastic, Nanang Eko Wahyuningtiyas, Heru Suryanto, Eddy Rudiyanto, Sukarni Sukarni, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Cassava starch based bioplasticfor packaging application has great potency because of the various starchproducing plants in Indonesia.Bioplasticcan contribute to reduce the dependence on fossil fuels andpetroleumthat can solve the environmentalproblem.Thepurpose of this research is to find out the thermal decomposition and the activation energy of cassava starch based bioplastic. The methods weresynthesis bioplastic with cassava starch as main component and glycerol as plasticizer. The thermogravimetry analysis was conducted to obtain the decomposition process mechanism of bioplastic and the heating valueof bioplasticwas measured using theadiabatic bomb calorimetric. Data analysis was conducted using a fitting model approach with an acikalin method to …

Bridge Build, Andrew Little

Student Scholarship

Bridge build design that includes not only a building process, but a research paper to make the best build possible as well.

Ptfe-Based Microreactor System For The Continuous Synthesis Of Full-Visible-Spectrum Emitting Cesium Lead Halide Perovskite Nanocrystals, Chengxi Zhang, Weiling Luan, Yuhang Yin, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Colloidal perovskite nanocrystals comprised of all inorganic cesium lead halide (CsPbX₃, X = Cl, Br, I or a mixture thereof) have potential as optical gain materials due to their high luminescence efficiency. In this work, cesium lead halide nanocrystals are continuously synthesized via a microreactor system consisting of poly(tetrafluoroethylene) (PTFE) capillaries. The synthesized nanocrystals possess excellent optical properties, including a full width at half maximum of 19–35 nm, high fluorescence quantum yield of 47.8–90.55%, and photoluminescence emission in the range of 450–700 nm. For the same precursor concentrations, the photoluminescence emission peak generally increases with increasing reaction temperature, …

Effect Of Oxide On Surface Tension Of Molten Metal, Chunkai Li, Yu Shi, Yufen Gu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Oxides as one of the commonly activating fluxes used in active tungsten inert gas welding (A-TIG welding) can dramatically increase the penetration depth to 2–4 times that of conventional welding. Using the oscillation principle of inviscid fluid, a robust method is developed to measure the average surface tension of molten metal during A-TIG welding for four different oxide activating fluxes of B₂O₃, TiO₂, SiO₂, and MgO. The experimental results suggest that the oxygen released from the decomposition of oxides is the dominant factor contributing to the change of the surface tension, which …