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Papers by Kevin Hadley

Journal of Engineering Education, Feb 10, 2022

While students possess procedural knowledge associated with engineering calculations and calculus... more While students possess procedural knowledge associated with engineering calculations and calculus, they often exhibit a disconnect between the conceptual meaning of mathematics and the problem being solved. This conceptual understanding of what mathematics “says” is defined by the theoretical framework of numeracy. Many engineering numeracy studies have been conducted, but they lacked a unifying theoretical framework, a common lexicon, or formal definitions to connect related numeracy topics.

Journal of Engineering Education, 2022

In nature, anti-freeze proteins present in fish utilize specific organic functionalities to disru... more In nature, anti-freeze proteins present in fish utilize specific organic functionalities to disrupt ice crystal formation and propagation. Based on these structures, surfaces with controlled chemical functionality and chain length were evaluated both experimentally and computationally to assess the effect of both parameters in mitigating ice formation. Linear aliphatic dimethylethoxysilanes terminated with methyl or hydroxyl groups were prepared, characterized, and used to coat aluminum. The effect upon icing using a microdroplet freezing apparatus and the Adverse Environment Rotor Test Stand found hydroxyl-terminated materials exhibited a greater propensity for ice formation and adhesion. Molecular dynamics simulations of a silica substrate bearing functionalized species of similar composition were brought into contact with a pre-equilibrated ice crystal. Several parameters including chain mobility were monitored to ascertain the size of a quasi-liquid layer. The studies suggested ...

Ice formation on aircraft surfaces effects aircraft performance by increasing weight and drag lea... more Ice formation on aircraft surfaces effects aircraft performance by increasing weight and drag leading to loss of lift. Current active alleviation strategies involve pneumatic boots, heated surfaces, and usage of glycol based de-icing fluids. Mitigation or reduction of in-flight icing by means of a passive approach may enable retention of aircraft capabilities, i.e., no reduction in lift, while reducing the aircraft weight and mechanical complexity. Under a NASA Aeronautics Research Institute Seedling activity, the effect of end group functionality and chain length upon ice adhesion shear strength (IASS) was evaluated with the results indicating that chemical functionality and chain length (i.e. molecular flexibility) affected IASS. Based on experimental and modeling results, diamine monomers incorporating molecular flexibility as either a side chain or in between diamine functionalities were prepared, incorporated into epoxy resins that were subsequently used to fabricate coatings o...

2016 IEEE Frontiers in Education Conference (FIE), 2016

Beyond the technical skills of engineering, students of any engineering discipline need to develo... more Beyond the technical skills of engineering, students of any engineering discipline need to develop teamwork knowledge, skills, and abilities (KSAs) in order to be successful. Various intervention strategies within education systems have been utilized to promote development of teamwork skills and practices in the past. The research team has incorporated the cooperative yet engaging activity based on the commercial board game Pandemic, where students work as a team to play against the game rather than against each other. The activity was introduced to three different engineering departments, highlighting its adoptability. While some discrepancies exist, the qualitative and quantitative data suggest the impact on a department is the same.

The top layer of the skin, known as the stratum corneum, acts as a barrier to foreign agents ente... more The top layer of the skin, known as the stratum corneum, acts as a barrier to foreign agents entering the body and to water leaving the body. Experimentally, while it is known that the lipids of the stratum cornenum are organized in lamellar bilayer structures in which the lipid chains are highly ordered, a detailed picture of the molecular organization of the lipids has not been elucidated. To help understand the molecular level arrangement of the skin lipids both atomistically detailed and coarse-grained molecular models for the three main classes of lipid found in the SC (ceramides, free fatty acids and cholesterol) have been developed for use in molecular dynamics simulations. Coarse-grained models allow molecular simulations to be performed on larger spatial and temporal scales than is possible through atomistic simulation alone and are necessary to study self-assembly in mixed lipid systems. Results will be presented for a number of pure and mixed lipid systems to demonstrate ...

Ice formation on aircraft, either on the ground or in-flight, is a major safety issue. While grou... more Ice formation on aircraft, either on the ground or in-flight, is a major safety issue. While ground icing events occur predominantly during the winter months, in-flight icing can happen anytime during the year. The latter is more problematic since it could result in increased drag and loss of lift. Under a Phase I ARMD NARI Seedling Activity, coated aluminum surfaces possessing hydrogen-bonding groups were under investigation for mitigating ice formation. Hydroxyl and methyl terminated dimethylethoxysilanes were prepared via known chemistries and characterized by spectroscopic methods. These materials were subsequently used to coat aluminum surfaces. Surface compositions were based on pure hydroxyl and methyl terminated species as well as mixtures of the two. Coated surfaces were characterized by contact angle goniometry. Receding water contact angle data suggested several potential surfaces that may exhibit reduced ice adhesion. Qualitative icing experiments performed under representative environmental temperatures using supercooled distilled water delivered via spray coating were inconclusive. Molecular modeling studies suggested that chain mobility affected the interface between ice and the surface more than terminal group chemical composition. Chain mobility resulted from the creation of “pockets” of increased free volume for longer chains to occupy. ABBREVIATIONS A: methyl terminated AFP: anti-freeze protein Al: aluminum ARMD: Aeronautics Research Mission Directorate CA: contact angle C#A: methyl terminated carbon chain length of #, where # = 3, 7, 11 C#H: hydroxyl terminated carbon chain length of #, where # = 4, 10, 11 F4: structure factor H: hydroxyl terminated HB: hydrogen-bonding LAMMPS: Large-scale Atomic /Molecular Massively Parallel Simulator MD: molecular dynamics MSD: mean squared diffusion NARI: NASA Aeronautics Research Institute Pt/C: platinum on carbon QLL: quasi-liquid layer RT: room temperature SHS: superhydrophobic surfaces TRL: Technology Readiness Level TBDS: t-butyldimethylsilyl VDW: van der Waals

The Journal of Chemical Physics, 2010

2008 AIChE Centennial Annual Meeting, 2008

Technology is a key component to the net generations social interaction, study skills, and profes... more Technology is a key component to the net generations social interaction, study skills, and professional practice. It is prudent to investigate the potential benefits of new technology in education. In this study, we incorporated a wiki into a senior design course, and investigated its benefits and downfalls with respect to implementing and learning design. We found it improved organization and interaction amongst the students and between the students and the professor and teaching assistant. We also discovered the potential wikis can contribute towards pedagogical research. For example, a wiki can provide insight into the thought process of a student with respect to how they approach design.

2017 ASEE Annual Conference & Exposition Proceedings

received his BS in Chemical Engineering at the Colorado School of Mines and his PhD in Chemical E... more received his BS in Chemical Engineering at the Colorado School of Mines and his PhD in Chemical Engineering at Vanderbilt University. At Vanderbilt, he also completed their teaching certificate program and was the first participant to publish the results of his project in a national peer-reviewed journal, Chemical Engineering Education. Afterwards, Dr. Hadley completed a postdoctoral study at NASA. IN 2012, he joined the faculty at South Dakota School of Mines and Technology in the Chemical and Biological Engineering department as an Assistant Professor. His discipline research interests include molecular modeling of smart materials. His engineering education research interests include numerical literacy, teamwork development, and failure as a scaffolding mechanism.

The Journal of Physical Chemistry B, 2010

Developing accurate models of water for use in computer simulations is important for the study of... more Developing accurate models of water for use in computer simulations is important for the study of many chemical and biological systems, including lipid bilayer self-assembly. The large temporal and spatial scales needed to study such self-assembly have led to the development and application of coarse-grained models for the lipid-lipid, lipid-solvent, and solvent-solvent interactions. Unfortunately, popular center-of-mass-based coarse-graining techniques are limited to modeling water with one water per be ad. In this work, we have utilized the K-means algorithm to determine the optimal clustering of waters to allow the mapping of multiple waters to single coarse-grained beads. Through the study of a simple mixture between water and an amphiphilic solute (1-pentanol), we find a four-water bead model has the optimal balance between computational efficiency and accurate solvation and structural properties when compared to water models ranging from one to nine waters per bead. The four-water model was subsequently utilized in studies of the solvation of hexadecanoic acid and the structure, as measured via radial distribution functions, for the hydrophobic tails and the bulk water phase were found to agree well with experimental data and their atomistic target.

Biophysical Journal, 2010

Fatty acids constitute one of the main components of the lipid lamellae in the top layer of the s... more Fatty acids constitute one of the main components of the lipid lamellae in the top layer of the skin, known as the stratum corneum, which acts as a barrier to foreign substances entering the body and to water leaving the body. To better understand the mechanics of the skin, a molecular-level understanding of the structure of the lamellae needs to be investigated. As a first step toward this goal, the current work involves the development of a coarse-grained model for fatty acids in an amorphous and a crystalline state. In order to retain the structural details of the atomistic molecules, radial distribution functions have been used to provide target data against which the coarse-grained force field is optimized. The optimization was achieved using the method developed by Reith, Pütz, and Müller-Plathe with a damping factor introduced into the updating scheme to facilitate the convergence against the crystalline radial distribution functions. Using this approach, a transferable force...

Molecular Simulation, 2012

Coarse-grained (CG) models have proven to be very effective tools in the study of phenomena or sy... more Coarse-grained (CG) models have proven to be very effective tools in the study of phenomena or systems involving large time- and length-scales. By decreasing the degrees of freedom in the system and using softer interactions than seen in atomistic models, larger time steps can be used and much longer simulation times can be studied. CG simulations are widely used to