Materials Science and Engineering Commons^™

Influence Of Hot-Dip Coatings On Mechanical And Corrosion Behaviors Of Steel Bolts, Thanit Kenhong, Gobboon Lothongkum, Yuttanant Boonyongmaneerat

Journal of Metals, Materials and Minerals

Steel is the main type of materials used in construction applications. Steel bolt, in particular, is used for fastening all the structural components together, and hence high durability in terms of the mechanical and corrosion resistance is inevitably critical. Carbon steel shows adequate mechanical strength, yet it is highly susceptible to corrosion. On the other hand, stainless steel is praised for its remarkable corrosion resistance, yet its relatively low yield stress exhibits a drawback. Hot-dip coating which provides Fe-Zn or Zn-Ni compounds in the coating interface could potentially mitigate the shortcomings of carbon steel and stainless steel by providing improved …

Structural Characterization Of Iron Oxides And Hydroxides In The Clay Fraction Of Soil From The Inca Civilization Moray Terraces, Maria Luisa Ceron Loayza, Jorge Aurelio Bravo Cabrejos, Felipe Americo Reyes Navarro, Rosio Ascuna Arcondo

Journal of Metals, Materials and Minerals

We introduce the structural characterization of the iron oxides and hydroxides in the clay fraction from soil collected in Moray terraces, Peru. It is important since these terraces are considered as a major technological advancement in agriculture in Inca Civilization times. We utilized the following: techniques of selective dissolution by dithionite-citrate-bicarbonate (DCB) and sodium hydroxide (NaOH); analytical techniques of X-ray diffractometry (XRD); and transmission Msbauer spectroscopy (TMS). XRD of the untreated samples showed that all the terraces contain quartz and calcite. After a treatment with NaOH and DCB, the peaks from quartz kept defined; XRD analysis shows a well-crystallized Fe3+ …

Study And Manipulation Of Electron Tunneling Through Quantum Dots, Pradeep Krishna Bhadrachalam

Material Science and Engineering Dissertations - Archive

Fermi-Dirac distribution is the fundamental property which governs the electron energy distribution in solids. At finite temperatures, Fermi-Dirac thermal smearing of electron energies limits the operation of many electronic, opto-electronic and spintronic devices. Examples include single electron transistors, quantum dot resonant tunnel diodes for single photon detection, and single electron turnstile devices. To overcome this intrinsic limitation of Fermi-Dirac thermal smearing, these devices have typically been operated at cryogenic temperatures. Room temperature operation of these devices could be realized, however, if the thermal smearing of electron energies could be suppressed. Until now, studies in the fields of electron-tunneling refrigerators and …

Temperature-Dependence Of Stress-Related Phenomena, Rahmat Saptono

Material Science and Engineering Dissertations - Archive

Efforts have been made to develop a simple but physically sound model. The model was specifically proposed to capture, explain, and estimate the temperature sensitivity and strengthening mechanism phenomena in small volume material with particular reference to the roles grain boundary and surface. Model-inspired phenomenology approach was applied to reveal the key mechanisms and find directions for a more complete constitutive model. The model was developed in the limited space where diffusion is insignificant. It was assumed that the plastic flow was predominantly governed by the thermally-activated process of dislocation glide overcoming barriers. Simple mathematical functions were formulated and evaluated …

Experimental And Numerical Study Of Phase Transition Of Lifepo₄ Material In Lithium Ion Batteries, Md Noor E Alam Siddique

Material Science and Engineering Dissertations - Archive

Phase transition behavior of LiFePO4 material has been studied in this work. During electrochemical charge/discharge processes, LiFePO4 transforms into FePO4 and this electrochemically driven phase transition of the two-phase system results in a potential plateau in a battery discharge curve. Besides, battery performance, especially under high rates, depends critically on this two-phase transition. However, this phase transition mechanism in the LiFePO4 crystal structure has yet not been understood in details. Developing better understanding is essential for designing high performing, safe and stable batteries.Currently available phase transition models for LiFePO4, such as the classical `core-shrinking model' and recently the `domino cascade …

Performance Analysis Of A Hybrid Raman Optical Parametric Amplifier In The O- And E-Bands For Cwdm Pons, Sasanthi Peiris, Nicolas Madamopoulos, Neophytos A. Antoniades, Dwight Richards, Roger Dorsinville

Publications and Research

We describe a hybrid Raman-optical parametric amplifier (HROPA) operating at the O- and E-bands and designed for coarse wavelength division multiplexed (CWDM) passive optical networks (PONs). We present the mathematical model and simulation results for the optimization of this HROPA design. Our analysis shows that separating the two amplification processes allows for optimization of each one separately, e.g., proper selection of pump optical powers and wavelengths to achieve maximum gain bandwidth and low gain ripple. Furthermore, we show that the proper design of optical filters incorporated in the HROPA architecture can suppress idlers generated during the OPA process, as well …

Corrosion Behaviour Of High Phosphorus Containing Cu-Cr Weather Resistant Steel, Gadadhar Sahoo, Anjana Deva, Balbir Singh, Atul Sexena

Journal of Metals, Materials and Minerals

Three steels viz., G22(Fe-0.072C-0.028 Si-0.20Mn-0.19P-0.38Cr-0.24Cu-0.17Ni), G32(Fe-0.072C-0.061 Si-0.23 Mn-0.19P-0.64Cr-0.14Cu) and SCOR (Fe-0.09C-0.37Si-0.42Mn-0.15P-0.37Cr-0.35Cu-0.31Ni) were made through ingot metallurgy route and hot rolled to 3 mm thick sheets. For other steels, similar corrosion rates were observed from the Tafel extrapolation study of freshly ground samples in 3.5% NaCl solution. Other technique employed to evaluate the effect of phosphorus on the formation of protective rust layer was electrochemical impedance spectroscopy (EIS) test after exposing the samples in an atmospheric exposure rack for four months on the roof top of a fourth floored building. Results revealed that the polarization resistance or rust resistance of G22 …

Effects Of Poly(Butylene Succinate) And Calcium Carbonate On The Physical Properties Of Plasticized Poly(Vinyl Chloride), Saowaroj Chuayjuljit, Phasawat Chaiwutthinan, Sitthipong Samutthong, Onusa Saravari, Anyaporn Boonmahitthisud

Journal of Metals, Materials and Minerals

In this studypoly(butylene succinate) (PBS) , a polymeric plasticizer, was partially replaced a conventional plasticizer, diisononyl phthalate (DINP) to avoid the plasticizer loss from poly(vinyl chloride) (PVC) overtime for various service conditions and to obtain a long-term plasticizer retention in the flexible PVC products. The plasticized PVC samples were prepared by melt mixing on a two roll mill, followed by compression molding. The mechanical properties (tensile properties, tear strength and hardness), thermal stability and morphology of the 20/20 phr (parts by weight per hundred parts of resin) DINP/PBS-plasticized PVC were evaluated and compared with those of the 40 phr DINP-plasticized …

Microstructural Development Of Galvanized Steels Prepared With Ni-P Electroless Deposited Pre-Coatings, Chulaluk Somphotch, Suparoek Henpraserttae, Ekasit Nisarattanaporn, Yuttanant Boonyongmaneerat

Journal of Metals, Materials and Minerals

An electroless pre-coating process is investigated as a possible method to prevent the sandelin effect, whereby steels containing silicon reacts rapidly with zinc during galvanization. From the microstructural and kinetics analysis, it is found that nickel-phosphorus electroless pre-coatings effectively serve as barriers to the reaction between Fe and Zn during galvanization, regardless of the silicon content in the steel substrates. Correspondingly, the coating thickness of the galvanized steels can be well-controlled.

Synthesis Of Porous Silica By Co-Micelle Emulsion Ternplating Technique Using Peg/Acrylamide And 2-(Acryloyloxy)-N,N,N-Trimethylethanaminium Chloride/Acrylamide As Templates, Iman Abdullah, Widyastuti Samadi, Arvinda Widyana, David Chandra Pandapotan, Ridla Bakri

Journal of Metals, Materials and Minerals

Co-micelle emulsion templating (co-MET) technique is a new method to synthesize uniform and ordered porous silica from tetraethylortosilicate precursor using double polymer as templates. In this study, co-MET technique was conducted by varying template type (namely PEG/acrylamide and 2(acryloyloxy)N,N,Ntrimethylethanaminium chloride/acrylamide) and percentage of polymer (2.5%, 5%, 10%, 15% and 20% for PEG and 0.5%, 1%, 2.5%, 5%, 10% for 2(acryloyloxy)N,N,Ntrimethylethanaminium chloride). The resulting porous silica were then characterized by SEM-EDS, BET and XRD to investigates the pore character and structure of silica. Based on SEM-EDS and BET analysis, it is shown that the amount and the type of polymer gave …

Mechanical Properties Of Poly(Lactic Acid) Composites Reinforced With Microfibrillated Cellulose Prepared Using High Speed Blending, Supachok Tanpichai, Jatuphorn Wootthikanokkhan

Journal of Metals, Materials and Minerals

Bamboo fibers, as a raw cellulose source, were used to prepare microfibrillated cellulose (MFC) using a high speed blender at 20,000 rpm for 60 min. Nanofibers with the width of less than 100 nm were disintegrated from the fibers. MFC networks were then prepared, and embedded in poly(lactic acid) resin using a compression molding at temperature of 180 C and a pressure of 10 MPa. Mechanical properties of poly(lactic acid) composites reinforced with MFC were investigated. The interaction between MFC fibrils and PLA resin was observed. As a result, Youngs modulus and tensile strength of the composites increased to 3.1 …

Microanalysis Of Polymer Chain Diffusion In Heat Seals, Russell Cooper

All Theses

Heat sealing is an integral method for the closure and protection of packaging. Previous work has shown that seal strength is developed by the interdiffusion of polymer chains within heat seals. Heat seals were made between two dissimilar materials. Poly(ethylene-co-acrylic acid) (EAA) was heat sealed to ionomer. Diffusion within the EAA-ionomer heat seals was estimated. The diffusion estimates were then related to resulting seal strength in the EAA-ionomer sealant system. Heated tooling sealing was utilized to make heat seals at 40 psi (275.79 kPa), 0.5 seconds, and a range of temperatures between 180˚F (82.22˚C) and 300˚F (148.89˚C). Scanning electron microscopy …

Fabrication And Characterization Of Magnetic Nanoparticle Composite Membranes, Akeem Cruickshank

All Theses

To effectively and accurately deliver drugs within the human body, both new designs and components for implantable micropumps are being studied. Designs must ensure high biocompatibility, drug compatibility, accuracy and small power consumption. The focus of this thesis was to fabricate a prototype magnetic nanoparticle membrane for eventual incorporation into a biomedical pump and then determine the relationship between this membrane deflection and applied pneumatic or magnetic force. The magnetic nanoparticle polymer composite (MNPC) membranes in this study were composed of crosslinked polydimethylsiloxane (PDMS) and iron oxide nanoparticles (IONPs). An optimal iron oxide fabrication route was identified and particle size …

Relationship Between Peel Force, Opening Force, And Burst Force For A Semi-Rigid Cup And Lid, Pre- And Post-Retort, Raj Navalakha

All Theses

This research determines if there is any relationship between the peel force, the opening force and the burst force for a semi-rigid cup and lid system, for pre- and post-retort conditions. It also compares the relationship (regression lines) between these forces pre- and post-retort. These seal results were studied by varying the sealing parameters of dwell time and temperature while keeping the pressure constant. Polypropylene cups and a peelable barrier retort lidding were used in this study. As compared to past research, a different peel testing technique was used to measure the peel and the opening force. The entire lid …

Printing Functional Electronic Circuits And Components, Ahmed Tausif Aijazi

Dissertations

The purpose of this study was to investigate the challenges in printing reliable multilayer flexible circuits, devices and components. Gravure was used as the primary printing process for this work, but due to some limitations of gravure, other printing methods were also investigated. At first a systematic study was done to determine the optimum parameters for the gravure printing of sub 50 micron lines. Commercially available silver nanoparticle inks were printed on a lab scale gravure printer, Accupress®. The highest resolution line that was electrically conductive was 36μm wide. The 9μm, 18μm and 27μm lines were printed but were not …

Investigation Of Fatigue Life And Fracture Mechanics Of Unconstrained Ni-Mn-Ga Single Crystals, Theodore Bryson Lawrence

Boise State University Theses and Dissertations

Ni-Mn-Ga is a magnetic shape memory alloy (MSMA) that exhibits large recoverable strains. The magnetic field induced strain (MFIS) occurs through twin boundary motion resulting in reorientation of the crystal structure, which is coupled to the magnetic moment of the material. The shape memory capabilities of the material make it promising for applications including microactuators, sensors, microfluid pumps, refrigeration, energy harvesting, and data storage.

In order for Ni-Mn-Ga to become a viable option for use in commercial applications the performance and reliability must be on par with industry standards. Ni‑Mn-Ga has been shown to achieve high cycles at low strains, …

Composite Films With Magnetic Nanorods: Fundamentals, Processing And Applications, Yu Gu

All Dissertations

This Dissertation is centered on studying the composite films with magnetic nanorods. In recent years, one-dimensional magnetic nanostructures, such as magnetic nanorods, chains of magnetic nanoparticles, and nanotubes filled with magnetic nanoparticles have caught great attentions due to the breadth of applications. Their unique magnetic and geometrical features open new avenues of studies in medicine, sensors, optofluidics, magnetic swimming, and microrheology. In particular, they offered great opportunities for design of multifunctional devices and for manufacturing of anisotropic nano- and microstructures with unprecedented magnetic and mechanical properties. However, the strategy for nanorod alignment in both Newtonian and complex fluids has not …

Effect Of Styrene-Methyl Methacrylate/Styrene-Butadiene Rubber On Properties Of Poly(Vinyl Chloride), Buranin Saengiet, Fuangfa Unob, Kawee Srikulkit

Journal of Metals, Materials and Minerals

Generally, poly(vinyl chloride) (PVC) without the addition of plasticizer or impact modifiers is rigid and brittle. The aim of this research was to improve the mechanical properties of PVC using styrene-methyl methacrylate/styrene-butadiene compound (SMMA/SBR rubber) as an impact modifier. The compound was obtained commercially. PVC containing SMMA/SBR rubber having SMMA/SBR phrs of 2.5, 5, 7.5 and 10 were prepared using two-roll mill set the conditions as follows: 170 oC and 5 min. Then, compression molding was carried out to prepare testing samples. FTIR analysis of SMMA/SBR rubber containing PVC samples showed the absorption band at 1732 cm-1 (C=O stretching), 3025 …

Effect Of Surfactant On Conductivity Of Poly(Pyrrole-Co-Formyl Pyrrole) Via Emulsion Polymerization, Sirilak Arunsawad, Kawee Srikulkit, Sarintorn Limpanart

Journal of Metals, Materials and Minerals

P(Py-co-FPy) were synthesized via emulsion polymerization, SDS and PSS used as surfactant and TFA as catalyst. Amounts of surfactant were vary as mole ratio of surfactant : monomer (0.25, 0.5 and 1.0). The synthesis copolymers were characterized by FTIR, SEM, particle size analyzer and four point probes. As a result of FT-IR spectra proved that the synthesized copolymers are associated with the structure of the P(Py-co-FPy). Spherical particles were detected by SEM and particles diameter is in range of 60-600 nm depending on type and amounts of surfactant. The electrical conductivity is in the range of 1.74x 10-5 to 2.21 …

Utilization Of Aqueous Raft Prepared Copolymers To Improve Anticancer Drug Efficacy, Andrew Christopher Holley

Dissertations

The advent of controlled radical polymerization (CRP) techniques, along with advancements in facile conjugation chemistry, now allow synthetic tailoring of precise, polymeric architectures necessary for drug/gene delivery. Reversible addition- fragmentation chain transfer (RAFT) polymerization and its aqueous counterpart (aRAFT) afford quantitative control over key synthetic parameters including block length, microstructure, and placement of structo-pendent and structo-terminal functionality for conjugation of active agents and targeting moieties. The relevance of water-soluble and amphiphilic (co)polymers synthesized by RAFT for in vitro delivery of therapeutics in biological fluids is an especially attractive feature. In many cases, polymerization, binding, conjugation, …