Performance Of Waterborne Intumescent Coating With Hybrid Industrial And Biofillers For Steel Protection,
2021
Universiti Malaya
Performance Of Waterborne Intumescent Coating With Hybrid Industrial And Biofillers For Steel Protection, Khairunisa Md Nasir
Student Works (2020-2029)
In recent decades, the disastrous accidents caused by damaged steel structure in the event of the fire have reminded people of the risk of fire in industrial buildings. The use of intumescent coatings is one of the most efficient methods to protect materials against fire. The coating comprises three active elements bounded together with a binder, which then reacts together at higher temperatures. Under the action of heat, the coating expands and forms a thick porous char layer to insulate the substance, thereby prolonging the building from collapsing under severe fire conditions. Considering ecological issues, the use of waterborne resin …
Study Of Schottky And Poole-Frenkel Conduction Mechanism In Fe304-Gamma-Fe2o3/Sio2/N-Type Si System,
2021
Universiti Malaya
Study Of Schottky And Poole-Frenkel Conduction Mechanism In Fe304-Gamma-Fe2o3/Sio2/N-Type Si System, Adrian Chung Ning Hann
Student Works (2020-2029)
The advances of metal oxide semiconductor technology (MOS) have led to smaller devices being made where sizes of the devices keep getting smaller and compact. Hence, all the components of metal oxide semiconductor sizes are to be reduced without affecting the overall efficiency of the metal oxide semiconductor. However, there is a problem in the silicon dioxide component of MOS as the sizes of the silicon oxide (SiO2) reduces, there is a possibility a current leakage to occur due to carrier direct tunneling effect passing through SiO2 which reduce the efficiency of the MOS. Therefore, a higher dielectric constant material …
International Journal Of Electrical And Computer Engineering,
2021
Southern University and A&M College
International Journal Of Electrical And Computer Engineering, Fred Lacy
Faculty Publications
A superconductor has the ability to conduct electricity perfectly and exclude magnetic fields from its interior. In order to understand electromagnetic characteristics of superconductors, their material properties need to be examined. To facilitate this understanding, a theoretical model based on concepts of electromagnetics is presented to explain the electrical and magnetic properties of superconductors. The permittivity response is the key aspect of the model and it describes the electrical resistance response and why it vanishes at the material’s critical temperature. The model also explains the behavior of magnetic fields and why they cannot exist inside superconducting materials. The theoretical concepts …
Structural Identification And Damage Detection In Bridges Using Wave Method And Uniform Shear Beam Models: A Feasibility Study,
2021
California State University, Long Beach
Structural Identification And Damage Detection In Bridges Using Wave Method And Uniform Shear Beam Models: A Feasibility Study, Mehran Rahmani, Manan Naik
Mineta Transportation Institute
This report presents a wave method to be used for the structural identification and damage detection of structural components in bridges, e.g., bridge piers. This method has proven to be promising when applied to real structures and large amplitude responses in buildings (e.g., mid-rise and high-rise buildings). This study is the first application of the method to damaged bridge structures. The bridge identification was performed using wave propagation in a simple uniform shear beam model. The method identifies a wave velocity for the structure by fitting an equivalent uniform shear beam model to the impulse response functions of the recorded …
Discrete Element Modeling Of Hydrogel Extrusion,
2021
Rowan University
Discrete Element Modeling Of Hydrogel Extrusion, Rohit Boddu
Theses and Dissertations
Hydrogels are widely used in extrusion bioprinting as bioinks. Understanding how the hydrogel microstructure affects the bioprinting process aids researchers in predicting the behavior of biological components. Current experimental tools are unable to measure internal forces and microstructure variations during the bioprinting process. In this work, discrete element modeling was used to study the internal interactions and the elastic deformation of the molecular chains within hydrogel networks during the extrusion process. Two-dimensional models of hydrogel extrusions were created in Particle Flow Code (PFC; Itasca Co., Minneapolis, MN). For our model's calibration, hydrogel compression testing was used in which a cluster …
Economics Of Grid-Tied Solar Photovoltaic Systems Coupled To Heat Pumps: The Case Of Northern Climates Of The U.S. And Canada,
2021
Michigan Technological University
Economics Of Grid-Tied Solar Photovoltaic Systems Coupled To Heat Pumps: The Case Of Northern Climates Of The U.S. And Canada, Joshua M. Pearce, Nelson Sommerfeldt
Michigan Tech Publications, Part 1
Solar photovoltaic (PV) technology is now a profitable method to decarbonize the grid, but if catastrophic climate change is to be avoided, emissions from transportation and heating must also decarbonize. One approach to renewable heating is leveraging improvements in PV with heat pumps (HPs). To determine the potential for PV+HP systems in northern areas of North America, this study performs numerical simulations and economic analysis using the same loads and climate, but with local electricity and natural gas rates for Sault Ste. Marie, in both Canada and U.S. Ground-mounted, fixed-tilt, grid-tied PV systems are sized to match 100% of electric …
Impact Of Grain Orientation And Phase On Volta Potential Differences In An Additively Manufactured Titanium Alloy,
2021
National Institute of Standards and Technology
Impact Of Grain Orientation And Phase On Volta Potential Differences In An Additively Manufactured Titanium Alloy, Jake T. Benzing, Olivia O. Maryon, Nik Hrabe, Paul H. Davis, Michael F. Hurley, Frank W. Delrio
Materials Science and Engineering Faculty Publications and Presentations
This work introduces a method for co-localized multi-modal imaging of sub-μm features in an additively manufactured (AM) titanium alloy. Ti-6Al-4V parts manufactured by electron beam melting powder bed fusion were subjected to hot isostatic pressing to seal internal porosity and machined to remove contour–hatch interfaces. Electron microscopy and atomic force microscopy-based techniques (electron backscatter diffraction and scanning Kelvin probe force microscopy) were used to measure and categorize the effects of crystallographic texture, misorientation, and phase content on the relative differences in the Volta potential of α-Ti and β-Ti phases. Given the tunability of additive manufacturing processes, …
Substituent Effects On The Solubility And Electronic Properties Of The Cyanine Dye Cy5: Density Functional And Time-Dependent Density Functional Theory Calculations,
2021
Boise State University
Substituent Effects On The Solubility And Electronic Properties Of The Cyanine Dye Cy5: Density Functional And Time-Dependent Density Functional Theory Calculations, Austin Biaggne, William B. Knowlton, Bernard Yurke, Jeunghoon Lee, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
The aggregation ability and exciton dynamics of dyes are largely affected by properties of the dye monomers. To facilitate aggregation and improve excitonic function, dyes can be engineered with substituents to exhibit optimal key properties, such as hydrophobicity, static dipole moment differences, and transition dipole moments. To determine how electron donating (D) and electron withdrawing (W) substituents impact the solvation, static dipole moments, and transition dipole moments of the pentamethine indocyanine dye Cy5, density functional theory (DFT) and time-dependent (TD-) DFT calculations were performed. The inclusion of substituents had large effects on the solvation energy of Cy5, with pairs of …
Absorption Of Nitrogen During Pulsed Wave L-Pbf Of 17-4 Ph Steel,
2021
Missouri University of Science and Technology
Absorption Of Nitrogen During Pulsed Wave L-Pbf Of 17-4 Ph Steel, Ben Brown, Joseph William Newkirk, Frank W. Liou
Materials Science and Engineering Faculty Research & Creative Works
In the fabrication of 17-4 PH by laser powder bed fusion (L-PBF) the well-documented occurrence of large amounts of retained austenite can be attributed to an elevated concentration of nitrogen present in the material. While the effects of continuous wave (CW) laser processing on in-situ nitrogen absorption characteristics have been evaluated, power modulated pulsed wave (PW) laser processing effects have not. In this study the effects of PW L-PBF processing of 17-4 PH on nitrogen absorption, phase composition, and mechanical performance are explored using commercially available PW L-PBF equipment and compared to samples produced by CW L-PBF. PW L-PBF samples …
Thermodynamic Prediction And Experimental Verification Of Multiphase Composition Of Scale Formed On Reheated Alloy Steels,
2021
Missouri University of Science and Technology
Thermodynamic Prediction And Experimental Verification Of Multiphase Composition Of Scale Formed On Reheated Alloy Steels, Richard Osei, Semen Naumovich Lekakh, Ronald O'Malley
Materials Science and Engineering Faculty Research & Creative Works
The structure, phase, and composition of scale formed on a continuously cast steel slab during reheating depend on intrinsic factors (steel chemistry, microstructure, and as-cast surface condition) and extrinsic parameters (temperature, time, composition, and velocity of combustion gas atmosphere). The scale that forms on a slab normally has several layers with differing compositions and phases and knowledge of this scale structure is important in subsequent descaling and hot rolling processing steps. Formation of multiphase scale structures on steel during high temperature oxidation in reheat furnace proceeds according to a local thermodynamic equilibrium, while thickness of layers depends on kinetic conditions …
The Hot Cracking Susceptibility Subjected The Laser Beam Oscillation Welding On 6xxx Aluminum Alloy With A Partial Penetration Joint,
2021
Korea Institute of Industrial Technology
The Hot Cracking Susceptibility Subjected The Laser Beam Oscillation Welding On 6xxx Aluminum Alloy With A Partial Penetration Joint, Minjung Kang, Jason Cheon, Dong Hyuck Kam, Cheolhee Kim
Mechanical and Materials Engineering Faculty Publications and Presentations
A laser beam oscillation method using Galvano mirrors, which allows wide weld beads and controls thermal stress distribution, was suggested to suppress the formation of solidification cracks in laser welds. In order to understand the solidification cracking behavior in relation to the bead shape, laser beam oscillation welding was performed under various oscillation widths and frequency conditions. To evaluate the effect of the oscillation parameter on solidification cracking susceptibility, a regression analysis based on the shape of the bead was performed. Stress distribution generated during the laser beam oscillation welding process was also analyzed using finite element modeling simulation. From …
Photoinduced Trapping Of Charge At Sulfur Vacancies And Copper Ions In Photorefractive Sn2P2S6 Crystals,
2021
Air Force Institute of Technology
Photoinduced Trapping Of Charge At Sulfur Vacancies And Copper Ions In Photorefractive Sn2P2S6 Crystals, Timothy D. Gustafson, Eric M. Golden, Elizabeth M. Scherrer, Nancy C. Giles, A. A. Grabar, Sergey A. Basun, Jonathan E. Slagle [*], Larry E. Halliburton
Faculty Publications
Electron paramagnetic resonance (EPR) is used to monitor photoinduced changes in the charge states of sulfur vacancies and Cu ions in tin hypothiodiphosphate. A Sn2P2S6 crystal containing Cu+ (3d10) ions at Sn2+ sites was grown by the chemical vapor transport method. Doubly ionized sulfur vacancies (V2+S) are also present in the as-grown crystal (where they serve as charge compensators for the Cu+ ions). For temperatures below 70 K, exposure to 532 or 633 nm laser light produces stable Cu2+ (3d9) ions, as electrons move from Cu+ ions to …
Nanoengineered Materials For Energy Conversion & Storage Applications: A Density Functional Theory Study,
2021
American University in Cairo
Nanoengineered Materials For Energy Conversion & Storage Applications: A Density Functional Theory Study, Ahmed Biby
Theses and Dissertations
The conventional approach for the development of novel materials has become long relative to the desired product development cycle. Thus, the sluggish pace of the development of materials within the conventional approach hinders the rapid transformation of the scientific outcomes into useful technological products. To this end, the field of hierarchical materials informatics evolved to bridge this gap. In this field, the multiscale material internal structure is considered the starting point and the core of this approach. This being said, the density functional theory (DFT) was used to generate useful materials data for the advancement of the hierarchical materials data-bases …
Assessment Of Heavy Metal Concentration In Soils Around Geita The Gold Mine, Tanzania,
2021
udsm
Assessment Of Heavy Metal Concentration In Soils Around Geita The Gold Mine, Tanzania, Mariam G. Mgendi, Mkabwa L. K Manoko, W.J.S. Mwegoha, C. Southway C. Southway
Journal of Humanities and Social Sciences
Health issues related to gold mining cannot be underestimated. Gold mining produce acid mine drainage (AMD), which in turn releases heavy metals into the nearby environment, hence causing environmental pollution. Heavy metals are naturally very toxic, thus pose a great health concern especially when their concentration exceeds the recommended permissible limits. In this study, concentrations of five heavy metals—including Pb, Ni, Cr, Cu and Zn—were assessed in the soil around Geita Gold Mine (GGM). A total of 17 sampling sites were established from which the soil samples were collected at 0-15cm and 15-30cm soil depth. The concentration of both total …
Synthesis And Characterization Of Perovskite-Based Materials For Memory Device Application,
2021
Universiti Malaya
Synthesis And Characterization Of Perovskite-Based Materials For Memory Device Application, Gregory Thien Soon How
Student Works (2020-2029)
This project aims to study the resistive switching behaviour in memory devices using perovskites-based structures. A hybrid organic-inorganic lead halide perovskite was studied in this project, specifically methylammonium lead triiodide, CH3NH3PbI3 or MAPbI3 perovskite. The effect of the various counter electrodes in MAPbI3 perovskite was investigated by fabricating MAPbI3 perovskite on Indium Tin Oxide (ITO). Three commonly used electrodes which are Aluminium (Al), Silver (Ag), and Gold (Au) were thermally evaporated on top of the MAPbI3 perovskite layer. It was found that the ITO/MAPbI3/Al exhibits Resistive Random Access Memory (ReRAM) behaviour with SET voltage (VSET) of 4.5 V and RESET …
Nanoscale Enhancement Of Photosensitized Radionuclide Stimulated Therapy,
2021
Washington University in St. Louis
Nanoscale Enhancement Of Photosensitized Radionuclide Stimulated Therapy, Daniel Douglas Lane
McKelvey School of Engineering Graduate Student Theses & Dissertations
Photodynamic therapy (PDT) provides efficient tumor killing through the generation of reactive oxygen species (ROS) from the optical excitation of a photosensitizer (PS). Furthermore, this mechanism is highly immune stimulating, providing systemic tumor immunity with a reduction in metastasis. However, these materials had previously been limited by their dependence upon external light sources, allowing treatment of only laser-accessible malignancy. With the recent development of photosensitized radiation stimulated therapy (PRaST) this depth dependence is broken through co-localization of radionuclides and semiconducting photosensitizers. This dissertation focuses on the enhancement of titanium dioxide (TiO2) based PRaST agents through understanding of TiO2 material parameters …
Multifunctional Polydopamine Nanomaterials For Biomedical And Environmental Applications,
2021
Washington University in St. Louis
Multifunctional Polydopamine Nanomaterials For Biomedical And Environmental Applications, Hamed Gholami Derami
McKelvey School of Engineering Graduate Student Theses & Dissertations
Polydopamine (PDA), a synthetic and organic material, has emerged as a promising materialplatform for various applications in energy, environmental, and biomedical fields. PDA, formed by self-polymerization of dopamine, is rich in catechol and amine groups, which facilitate covalent conjugation and/or other non-covalent interactions with organic and inorganic materials. It is highly biocompatible, biodegradable, has broadband light absorption spectrum and excellent light-to-heat conversion efficiency. Also, it is easy to synthesize and functionalize. The combination of excellent characteristics of polydopamine-based nanomaterials, make them a promising adsorbent agent for environmental wastewater treatment and photothermal agent for biomedical applications. In the first half of …
Mechanical Strength Of Germanium Doped Low Oxygen Concentration Czochralski Silicon And The Effect Of Oxygen On Nitrogen Dissociation In Silicon,
2021
Washington University in St. Louis
Mechanical Strength Of Germanium Doped Low Oxygen Concentration Czochralski Silicon And The Effect Of Oxygen On Nitrogen Dissociation In Silicon, Junnan Wu
McKelvey School of Engineering Graduate Student Theses & Dissertations
During the Czochralski growth of silicon, it is inevitable for oxygen to be incorporated into the silicon crystal from the quartz crucible. Interstitial oxygen improves the mechanical strength of silicon by pinning and locking dislocations, but also generates thermal donors during device processes, shifting the electrical resistivity. For silicon wafers used in radio frequency (RF) applications, it is important to ensure the high resistivity of the substrates for good RF characteristics. Therefore, the oxygen level in these high resistivity silicon wafers is kept very low (< 2.5 × 1017 atoms/cm3) by carefully controlling the Czochralski growth conditions, in order to reduce the thermal donor concentration to an acceptable level. Silicon on insulator (SOI) substrates made from high resistivity wafers have been widely used for RF applications. SOI manufacturing includes multiple high temperature thermal cycles (1000 – 1100 °C), during which the high resistivity wafers are prone to slip and warpage. Therefore, it is technologically important to recover some of the lost mechanical strength due to the lack of oxygen by introducing electrically inactive impurities to suppress the dislocation generation and mobility in silicon. Germanium (Ge) as an isovalent impurity is 4% larger in size and forms a solid solution with silicon in the entire concentration range. Previous works have shown Ge doping at high concentrations above 6 × 1019 atoms/cm3 increased mechanical strength of silicon with high oxygen concentration (~ 1 × 1018 atoms/cm3). In this work, we explore the effect of Ge doping (7 - 9 × 1019 atoms/cm3) on the mechanical strength of low oxygen concentration (< 2 × 1017 atoms/cm3) silicon, where the oxygen associated dislocation locking and pinning are very low. A mechanical bending test was used to study the average dislocation migration velocity and the critical shear stress of dislocations motion at 600 – 750 °C for Ge doped, nitrogen doped, and undoped low oxygen samples, as well as nitrogen doped float-zone and un-doped high oxygen concentration samples. Next, we fabricated SOI substrates using these high resistivity wafers and compared their slip generation rates and the slip-free epitaxial grow temperature windows after the high temperature thermal cycles (> 1000 °C). Our results indicate at lower temperature Ge doesn’t affect the dislocation mobility …
Flexible Nanopaper Composed Of Wood-Derived Nanofibrillated Cellulose And Graphene Building Blocks,
2021
Rowan University
Flexible Nanopaper Composed Of Wood-Derived Nanofibrillated Cellulose And Graphene Building Blocks, Qing Li, Ming Dai, Xueren Qian, Tian Liu, Zhenbo Liu, Yu Liu, Ming Chen, Wang He, Suqing Zeng, Yu Meng, Chenchen Dai, Jing Shen, Yingtao Liu, Wenshuai Chen, Wenbo Liu, Ping Lu
College of Science & Mathematics Departmental Research
Nanopaper has attracted considerable interest in the fields of films and paper research. However, the challenge of integrating the many advantages of nanopaper still remains. Herein, we developed a facile strategy to fabricate multifunctional nanocomposite paper (NGCP) composed of wood-derived nanofibrillated cellulose (NFC) and graphene as building blocks. NFC suspension was consisted of long and entangled NFCs (10–30 nm in width) and their aggregates. Before NGCP formation, NFC was chemically modified with a silane coupling agent to ensure that it could interact strongly with graphene in NGCP. The resulting NGCP samples were flexible and could be bent repeatedly without any …
Research Trend Of Metal Matrix Composites Reinforced With Silica Extracted By Green Route: A Bibliometric Analysis,
2021
Symbiosis Institute of Technology (SIT), Symbiosis International (Deemed University) (SIU), Lavale, Pune, India
Research Trend Of Metal Matrix Composites Reinforced With Silica Extracted By Green Route: A Bibliometric Analysis, Rinku Datkhile, Meena Laad, Babaji Ghule
Library Philosophy and Practice (e-journal)
Metal Matrix Composites have acquired an important place in the engineering applications due to their distinctive characteristics such as high specific strength, lower specific gravity, improved material stiffness, better durability, enhanced creep and fatigue strength etc. Worldwide scientists are working on the improvement of mechanical properties of composite materials. The present work attempts to summarise all the research carried out on metal matrix composites reinforced with silica extracted by green route and provides up-to-date research material for researchers who are interested in the field of composites with metal matrices. Scopus databases and software such as Gephi Vos Viewer and Table2Net …
