Questaal: A Package Of Electronic Structure Methods Based On The Linear Muffin-Tin Orbital Technique,
2020
King's College London
Questaal: A Package Of Electronic Structure Methods Based On The Linear Muffin-Tin Orbital Technique, Dimitar Pashov, Swagata Acharya, Walter R.L. Lambrecht, Jerome Jackson, Kirill Belashchenko, Athanasios Chantis, Francois Jamet, Mark Van Schilfgaarde
Kirill Belashchenko Publications
This paper summarises the theory and functionality behind Questaal, an open-source suite of codes for calculating the electronic structure and related properties of materials from first principles. The formalism of the linearised muffin-tin orbital (LMTO) method is revisited in detail and developed further by the introduction of short-ranged tight-binding basis functions for full-potential calculations. The LMTO method is presented in both Green's function and wave function formulations for bulk and layered systems. The suite's full-potential LMTO code uses a sophisticated basis and augmentation method that allows an efficient and precise solution to the band problem at different levels of theory, …
Effects Of Intrinsic Defects And Alloying With Fe On The Half-Metallicity Of Co2Mnsi,
2020
University of Nebraska - Lincoln
Effects Of Intrinsic Defects And Alloying With Fe On The Half-Metallicity Of Co2Mnsi, G. G. Baez Flores, Ivan A. Zhuravlev, Kirill Belashchenko
Kirill Belashchenko Publications
The electronic structure and half-metallic gap of Co2MnSi in the presence of crystallographic defects, partial Fe substitution for Mn, and thermal spin fluctuations are studied using the coherent potential approximation and the disordered local moment method. In the presence of 5% Co or Mn vacancies the Fermi level shifts down to the minority-spin valence-band maximum. In contrast to NiMnSb, both types of Mn antisite defects in Co2MnSi are strongly exchange coupled to the host magnetization, and thermal spin fluctuations do not strongly affect the half-metallic gap. Partial substitution of Mn by Fe results in considerable changes in the Bloch spectral …
Responsive Economic Model Predictive Control For Next-Generation Manufacturing,
2020
Wayne State University
Responsive Economic Model Predictive Control For Next-Generation Manufacturing, Helen Durand
Chemical Engineering and Materials Science Faculty Research Publications
There is an increasing push to make automated systems capable of carrying out tasks which humans perform, such as driving, speech recognition, and anomaly detection. Automated systems, therefore, are increasingly required to respond to unexpected conditions. Two types of unexpected conditions of relevance in the chemical process industries are anomalous conditions and the responses of operators and engineers to controller behavior. Enhancing responsiveness of an advanced control design known as economic model predictive control (EMPC) (which uses predictions of future process behavior to determine an economically optimal manner in which to operate a process) to unexpected conditions of these types …
Impact Of Team Formation Approach On Teamwork Effectiveness And Performance In An Upper-Level Undergraduate Chemical Engineering Laboratory Course,
2020
University of Dayton
Impact Of Team Formation Approach On Teamwork Effectiveness And Performance In An Upper-Level Undergraduate Chemical Engineering Laboratory Course, Erick S. Vasquez, Matthew J. Dewitt, Zachary J. West, Michael J. Elsass
Chemical and Materials Engineering Faculty Publications
This study focuses on the impact of team formation approach on teamwork effectiveness and performance spanning three years of instruction of the chemical engineering unit operations laboratory, which is an upper-level undergraduate laboratory course. Team formation approaches changed each year, and assessment tools, including peer-assessment, academic performance, and course evaluations, were employed to evaluate team performance. Approaches included three cases: instructor-selected teams based on GPA with the objective of a similar cumulative average GPA for each team, student self-selected teams, and a combination of self-selected teams with instructor-selected teams for a final experiment. For the third case, new teams were …
Performance Evaluation Of Lightweight Normal And Geopolymer Foamed Concrete Using Palm Oil Fuel Ash As Partial Replacement Of Binder,
2020
Universiti Malaya
Performance Evaluation Of Lightweight Normal And Geopolymer Foamed Concrete Using Palm Oil Fuel Ash As Partial Replacement Of Binder, M .E. Alnahhal Ahmed
Student Works (2020-2029)
Carbon dioxide (CO2) emissions from Ordinary Portland Cement (OPC) have a detrimental effect on the environment and this had led many researchers to search for other alternatives in the form of sustainable cementitious materials. The depletion of natural resources and dumping the industrial by-products and waste materials are serious concern to our environment. This research focusses on the performance of using a palm oil industrial by-product, namely, palm oil fuel ash (POFA), as a partial replacement for OPC and fly ash (FA) in lightweight normal foamed concrete and lightweight geopolymer foamed concrete, respectively. Thus, using 10, 20, and 30% POFA …
Thermally Driven Spin Transport In Ferromagnetic Metals,
2020
University of Denver
Thermally Driven Spin Transport In Ferromagnetic Metals, Wafa Saud Aljuaid
Electronic Theses and Dissertations
Since the discovery in 2008, the spin Seebeck effect has become one of the most active topics in the spin caloritronics research field. It opened a new way to create spin current by a combination of magnetic fields and heat. A temperature gradient in ferromagnetic (FM) metals generates a ow of spin current due to split of spin chemical potential between spin up and spin down electrons. This thermal spin current has been detected using an attached nonmagnetic heavy metal with large spin Hall angle via the inverse spin hall effect (ISHE). A voltage signal is generated since the nonmagnetic …
Plasmon-Enhanced Optical Probes For Sensing Of Drug Metabolite,
2020
West Virginia University
Plasmon-Enhanced Optical Probes For Sensing Of Drug Metabolite, Jennifer Boryczka
Graduate Theses, Dissertations, and Problem Reports (ETD)
An Au@SiO2 core-shell nanostar structure was synthesized along with CuInS2 quantum dots. The quantum dots display near-infrared fluorescence. In this work, the nanostar structure was functionalized with antibodies and then was utilized as a SERS probe for drug metabolite detection. Drugs are an illicit substance that police, medics, and hospitals need to know if an individual is under the influence of but that individual will not always be willing or able to provide that information. A sensor based on this new probe has been developed for detection of drug metabolites in buffer.
Magnetism In Γ-Fesi2 Nanostructures: A First Principles Study,
2020
Michigan Technological University
Magnetism In Γ-Fesi2 Nanostructures: A First Principles Study, Sahil Dhoka
Dissertations, Master's Theses and Master's Reports
First-principles calculations are performed on γ-FeSi2 nanostructures grown on Si (111) and (001) substrate. An attempt to explain the origin of emergent magnetic properties of the metastable gamma phase of iron di-silicide (γ-FeSi2) is made, which show ferromagnetic behavior on nanoscale, unlike its possible bulk form. Many papers try to explain this magnetism from factors like bulk, epitaxial strain, interface, surface, edges, and corners but doesn’t provide an analytical study for these explanations. Density functional theory is used to analyze the magnetic effects of these factors. The results for the epitaxial structures show no magnetic behavior for …
Jominy Hardenability Tester With In-Situ Heating,
2020
The University of Akron
Jominy Hardenability Tester With In-Situ Heating, Luke Allen
Williams Honors College, Honors Research Projects
This project centers on building a Jominy Hardenability tester with In-Situ heating for the manufacturing lab at the University of Akron. A new process and setup will be designed using engineering concepts in order to make the testing more efficient and safer for the teaching and testing of metal hardness. The current Jominy testing setup has efficiency issues within the transfer of specimen from induction heater to testing rig. Our design will simplify the design by creating a test rig that removes the traveling aspect of the specimen which will limit the amount of premature cooling done and will be …
Table Top Dome Tester,
2020
The University of Akron
Table Top Dome Tester, Travis Bernard, Sarah Kassinger, Amanda O'Reilly, Scott Salerno
Williams Honors College, Honors Research Projects
The Erichsen Cupping Test was used as a basis to design a dome tester. The intention of a dome tester is to test sheet metal material properties in all directions. This was done by clamping a piece of sheet metal and using a piston and hydraulic press to punch through the material. The force used to punch the material and the height of the deforming material can be gathered and the sheet metal properties can then be calculated. At the end of the project the team was able to successfully design and manufacture a hydraulic dome tester. However, due to …
Solvent-Free Coating Using Maco Bio-Based Reactive Diluent,
2020
The University of Akron
Solvent-Free Coating Using Maco Bio-Based Reactive Diluent, Ryder James
Williams Honors College, Honors Research Projects
The project performed utilizes methacrylated cardanol (MACO) and a linseed oil resin to test how different weight percentages of MACO affect coating performance. MACO is synthesized from a phenolic lipid extracted from cashew nut shells, which are a cashew industry waste product. Not only does it utilize a waste product, but being a bio-based reactive diluent means it can replace the use of volatile organic solvents that are harmful to both humans and the environment. Weight percentage samples of 0%, 10%, 20%, 30%, and 40% were used. Coatings were applied using a 6-mil drawn down bar, with samples being prepared …
Tabletop Mechanical Tester,
2020
The University of Akron
Tabletop Mechanical Tester, Jamie Dombroski, Brian English, Richard Leffler, Andrew Shirk
Williams Honors College, Honors Research Projects
The need for hands-on and face-to-face experiences in the engineering classroom is very great. The equations, principles, and concepts can all be learned, but without the visual and tactile application, these don’t always sink in or become concrete. A small-scale tensile test machine was designed, sourced, manufactured, and tested for the purpose of being applied in classroom settings to provide this experience to engineering students. Extensive research was performed concerning tensile machines on the market, the essential elements of which are the load cell, grips, crosshead, extensometer, motor, and frame. The raw materials for the frame were purchased and drawings …
Magnetic Refrigerator Device Based On La (Fexcoysi1-X-Y)13,
2020
Virginia Commonwealth University
Magnetic Refrigerator Device Based On La (Fexcoysi1-X-Y)13, Khushar Javed
Theses and Dissertations
Particles of Lanthanum-iron-silicide, La (FexCoySi1-x-y)13exhibit different magnetic properties when stored in air compared to the same stored in water. The sample with a nominal composition of La(Fe0.842Co0.073Si0.084)13was prepared by arc-melting from elements under argon atmosphere. In recent years, there has been research conducted on different processes that could drastically reduce energy costs of cooling and replacing gas compressors with magnetocaloric materials. Magnetization measurements were carried out on this magnetocaloric material to characterize it in order to design magnetic refrigerator device based on it. The …
Chloride Effect In Fly Ash Geopolymer Cement,
2020
The University of Akron
Chloride Effect In Fly Ash Geopolymer Cement, Evan Dimmick
Williams Honors College, Honors Research Projects
The production of ordinary portland cement (OPC) poses a significant impact on the world's carbon dioxide emissions through the wide global use of concrete. Geopolymer cements (GPC) made from alkali activated fly ash can serve as a replacement to OPCs, reducing the carbon dioxide emissions by as much as 80%. GPCs exhibit adequate or superior mechanical performance to OPCs. The corrosion of carbon steel rebar in concrete occurs largely from chloride ion attack. The focus of this project will be to experimentally determine the coefficient of diffusion for chloride ions in GPCs and OPCs and compare to the corrosion performance …
Effects Of Sensitization On Intergranular Boundaries Of Aluminum Alloy 5083,
2020
The University of Akron
Effects Of Sensitization On Intergranular Boundaries Of Aluminum Alloy 5083, Kyle Balentine
Williams Honors College, Honors Research Projects
The purpose of this Honors Research Project is to show the effect of sensitization on intergranular corrosion (IGC) on AA5083. Sensitization is the process of a material to experience microstructural phase change, caused by thermal treatment, which promotes precipitation of secondary phases on the grain boundaries. The nitric acid mass loss test (NAMLT), SEM analysis, cyclic potentiodynamic polarization (CPP), and Electrochemical Impedance Spectroscopy (EIS) were performed to find a correlation to the degree of sensitization (DOS) and the pitting and IGC mechanisms. The DOS increased as heat treatment was applied. The SEM images displayed no clear precipitates on the grain …
Investigation On The Mechanical Properties And Microstructure Analysis Of Micro-Resistance Spot Welding Between Stainless Steel 316l And Tl-6al-4v,
2020
Universiti Malaya
Investigation On The Mechanical Properties And Microstructure Analysis Of Micro-Resistance Spot Welding Between Stainless Steel 316l And Tl-6al-4v, Mohd Mansor Muhammad Safwan
Student Works (2020-2029)
In this study, ASS 316L and Ti-6Al-4V were welded together by micro-resistance spot welding (μRSW) at different combinations of welding parameters using specifically design electrode geometry in order to acquire the optimal combination of welding parameters. The welded joint were subjected to tensile shear strength test to determine the influence of welding current, welding time, welding force and different design of elctrode tip on the mechanical properties and the strength of the welded joint. The experiment was conducted by using full factorial design of experiment (DoE) with L27 orthogonal array and utilizing the analysis of variance (ANOVA) to obtain the …
Organophosphorus-Hydrazides As Potential Reactive Flame Retardants For Epoxy,
2020
University of Dayton
Organophosphorus-Hydrazides As Potential Reactive Flame Retardants For Epoxy, Alexander B. Morgan, Vladimir Benin, Donald A. Klosterman, Abdulhamid Bin Sulayman, Mustafa Mukhtar, Mary L. Galaska
Chemical and Materials Engineering Faculty Publications
For structural composites used in vehicles and aircraft, flame retardant chemistries which enhance char formation and reduce heat release are preferred. Phosphorus-based and phosphorus–nitrogen flame retardants for epoxies have been well studied to date, but phosphorus hydrazides have not been studied for their flame-retardant potential in epoxy. These hydrazides offer some novel structures and they can potentially offer a combination of vapor and condensed phase flame retardant action. A series of eight compounds were systematically investigated in this study as reactive flame retardants in a bisphenol F epoxy/aliphatic amine resin system at a level of 2.5 wt% phosphorus. Results suggest …
Designing Composites For Graceful Failure,
2020
The British University in Egypt
Designing Composites For Graceful Failure, Amany G. Micheal Prof., Yehia Ahmed Bahei El Din Prof.
Architectural Engineering
When inevitable, failure in composite laminates is preferred to occur gracefully to avoid loss of property and possibly life. While the inherent inhomogeneity leads to slow dissipation of damage-related energy, overall failure is fiber-dominated and occurs in a rather brittle manner. Multidirectional plies usually give a more ductile response. Additionally, stiffness and strength as well as cost are important factors to consider in designing composite laminates. It is hence desirable to optimize for high mechanical properties and low cost while keeping graceful failure. Designing composite laminates with hybrid systems and layups, which permit gradual damage energy dissipation, are two ways …
Assessing Magnetic Iron Oxide Nanoparticles Properties Under Different Thermal Treatments,
2019
University of Dayton
Assessing Magnetic Iron Oxide Nanoparticles Properties Under Different Thermal Treatments, Erick S. Vasquez, Evan M. Prehn, Keisha B. Walters
Chemical and Materials Engineering Faculty Publications
Magnetic nanoparticle structures have been examined as potential carrier vehicles and substrates in a wide range of applications where they undergo mechanical, chemical and/or thermal manipulation to allow for their modification, conjugation and transport. For safe and effective use, it is imperative to not only measure the initial physicochemical and structural properties of nanomaterials, but also identify and quantify any property changes related to a loss of chemical and/or physical integrity during processing and usage conditions. In this study an assessment of iron oxide magnetic nanoparticle thermal stability using modulated differential scanning calorimetry (mDSC) and a controlled-heating system is conducted …
Effect Of Incorporating Pottery And Bottom Ash As Partial Replacement Of Cement,
2019
The Islamic University of Gaza
Effect Of Incorporating Pottery And Bottom Ash As Partial Replacement Of Cement, Bassam A. Tayeh, Doha M. Alsaffar, Lawend K. Askar, Asmahan Issa Jubeh
Karbala International Journal of Modern Science
This study addressed the environmental constraints in cement production. Ordinary Portland cement (OPC) was replaced with pottery powder (PP, produced by grinding locally available pottery) and bottom ash (BA) at 10%, 20% and 30% of cement mass. Moreover, 4% calcium chloride solution (CaCl2.2H2O) was used as mixing water. Material properties, such as standard consistency, setting time and compressive strength, were measured with different percentages of OPC replacement with PP and BA. Results indicated that the replacement with PP and BA increased the water demand to achieve the standard consistency. These results revealed that the strength evolution …
