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Teaching engineering students how to effectively communicate using the language, representations, and tools specific to their discipline is important to their development as practitioners in their respective fields. This article describes a literature review of learning activities intended to teach crystal structure and crystallography and explores the extent to which educators implement elements of disciplinary literacy. We categorized the purpose of the paper, what the students are asked to do, the representations used in the activities, and the learner roles that the activities support. We observe that a majority of the papers engage students in disciplinary practices and support many, but not all aspects of disciplinary literacy. Instructors use a variety of representations in presenting concepts and ask students to interact with the learning activities to recount information or interpret results. However, we find that the activities rarely ask students to synthesize new information or evaluate their information in any wider context. We suggest that instructors should aim to implement the entire range of learning roles, and employ more critical socio-cultural approaches when designing learning activities to make the sciences accessible to a more diverse population of learners.

Background: Demographic characteristics are known to influence participation in cocurricular activities. Less studied are the effects of other background characteristics. Purpose: We hypothesize that considering college knowledge and students' proactive behaviors in tandem with demographics provides better models for predicting such participation. Method: We developed a questionnaire and administered it to 3,618 domestic third- and fourth-year undergraduate engineering students at a large public R1 Midwestern university, yielding 860 responses. Logistic regression models predicting five types of cocurricular participation were constructed with demographic characteristics, college knowledge, and proactive behaviors in all combinations as predictors. Results: Four of five types of cocurricular participation were better modeled using factors beyond demographics. Two were better modeled using only proactive behavior as predictors and two were better modeled using demographics in combination with either college knowledge or proactive behavior. Only one type of participation could be best predicted by demographics alone. Conclusions: These findings contribute quantitative evidence establishing relationships between participation in engineering cocurricular activities and a wider range of factors than previously reported. Furthermore, they provide guidance for creating intervention programs because, unlike demographics, college knowledge and proactive behavior can be shaped by either the individual or the institution.

In large lecture courses, it can be challenging for instructors to address student misconceptions, supplement background knowledge, and identify ways to motivate the various interests of all students during the allotted class time. Instructors can harness instructional technology such as screencasts, recordings that capture audio narration along with computer screen images, to supplement the lecture with content that addresses the diversity in student academic backgrounds, motivations, and interests, to extend the classroom experience, and reach the individualized needs of students. This study documents the strategic use of screencasts in a large introductory Materials Science and Engineering (MSE) course, and examines their impact on student usage and course performance. To assess the efficacy of screencasts, students were surveyed to determine how they used screencasts and whether they perceived these resources to be helpful. In addition, we correlated student usage based on website hits with student performance (e.g. final grade) to determine statistical significance. Since the course is comprised of students from different academic and social backgrounds, we also analyzed usage and performance patterns for particular student subgroups. The results indicate that students perceive the screencasts to be helpful and tend to use the resources as a study supplement. Overall, usage of screencasting in its various forms is positively and significantly correlated with course performance as indicated by the final grade. The most substantial gains were found for students with the least amount of prior exposure to concepts in the course material. These results indicate a potential for screencasts to address the various academic needs of students in a large lecture environment.

A technique is described for continuous production of microparticles of variable size with new forms of anisotropy including alternating bond angles and configurable patchiness. The studies have shown that the particle's sequence is dynamically controlled through fluidic processing.

The interaction between Sb and As is investigated by scanning tunneling microscopy of InAs (001) surfaces. Sb roughens the surface by increasing the coverage of divots (vacancy clusters) and two dimensional islands, which both possess a c(4×4) reconstruction. ab initio total energy calculations predict that the As-terminated b2(2×4) transforms into In-Sb heterodimer terminated c(4×4) configurations with increasing Sb chemical potential, which causes the roughening by pulling atoms from the terrace. Thus we propose an alternative model for interfacial broadening by intermixing rather than by surface segregation. [ABSTRACT FROM AUTHOR]

Droplet epitaxy (DE) has emerged as an alternative to Stranski-Krastanov (SK) as a method for epitaxial nanostructure formation. We find significant structural differences of similar sized nanostructures embedded in GaAs between the two methods. Atomic force microscopy and atom probe tomography measurements reveal that uncapped and capped SK structures resemble each other. However, the DE nanostructures appear as rings topographically but are quantum dots compositionally. A GaSb wetting layer is present regardless of the growth method and shares a nearly identical Sb concentration profile. DE nanostructures are shown to have a lower Sb concentration, and transmission electron microscopy measurements reveal that they produce less strain on the capping layer. Despite significant structural differences, SK and DE nanostructures exhibit the same photoluminescence response, suggesting that the emission is from a shared feature such as the wetting layer, rather than the nanostructures. [ABSTRACT FROM AUTHOR]

GaAsBi is of great interest for applications in high efficiency optoelectronic devices due to its highly tunable bandgap. However, the experimental growth of high Bi content films has proven difficult. Here, we model GaAsBi film growth using a kinetic Monte Carlo simulation that explicitly takes cation and anion reactions into account. The unique behavior of Bi droplets is explored, and a sharp decrease in Bi content upon Bi droplet formation is demonstrated. The high mobility of simulated Bi droplets on GaAsBi surfaces is shown to produce phase separated Ga-Bi droplets as well as depressions on the film surface. A phase diagram for a range of growth rates that predicts both Bi content and droplet formation is presented to guide the experimental growth of high Bi content GaAsBi films. [ABSTRACT FROM AUTHOR]

Bi incorporation in GaAs and GaSb has exhibited some promising properties allowing for potential new materials operating in the infrared regime. The growth of these materials has proven difficult, often leading to surfaces covered in droplets or nonuniformity in the composition. We propose a new kinetic model to capture the dynamics of incorporation and droplet formation in the growth of these alloys. The model accurately predicts trends found experimentally. Furthermore, the model shows that compositional nonuniformity arises due to a reduction in the incorporation rate of Bi caused by the nucleation of droplets. [ABSTRACT FROM AUTHOR]

Student socialisation into the norms and environment of their institution is a crucial process during their college experience. During the COVID-19 pandemic, these processes were disrupted, and little published research exists exploring comparisons of these student socialisation processes before and during the pandemic. Accordingly, we report on a quantitative study conducted at a large mid-western university in the United States, which compared survey data from 2018 to data collected in 2021. We operationalised student socialisation processes using Ashford and Black’s proactive behaviours scale to explore how these behaviours and relevant socialisation outcomes changed from before to during the pandemic. The primary socialisation outcomes of interest were engineering identity and social capital. During the COVID pandemic, students reported lower levels of social capital. However, we simultaneously observed higher ratings of students’ engineering identity. Next, using multivariate linear regression, we examined which proactive behaviours best predicted socialisation outcomes in both datasets. We found all proactive behaviours were significant predictors of social capital. Proactive behaviours did not influence student’s sense of engineering identity. This study contributes to the growing literature on the pandemic's impact on engineering undergraduate students and how proactive behaviours are related to their socialisation outcomes. [ABSTRACT FROM AUTHOR]

Experiential learning has been linked to improved outcomes for students in higher education. In engineering, experiential learning is viewed as highly aligned with the pedagogy of engineering education, however, consensus on which outcomes are relevant and how they are defined has not been established. This literature review explores how engineering education literature has defined a set of twelve competencies linked to experiential learning in engineering. A synthesis of literature defining Communication, Creativity, Empathy, Entrepreneurial Mindset, Ethics, Global and Cultural Awareness, Grit I Persistence I Resilience, Leadership, Lifelong Leaming, Ability to Accept and Manage Risk, Systems Thinking, and Teamwork is presented. [ABSTRACT FROM AUTHOR]

The phase diagram of the Bi/GaSb surface reconstructions has been established using density functional theory and cluster expansion computational methods. The predominant reconstructions in the alloy system are the same as those found for pure GaSb. That is, the (4 ×3) family of reconstructions dominate the phase diagram. However, at low Sb and Bi chemical potentials, the calculations predict a (2 × 1) structure for both GaSb and Bi/GaSb. It is found that Bi does not stabilize any additional structures, and Bi does not readily incorporate into the surface in the presence of Sb. [ABSTRACT FROM AUTHOR]

The influence of using a Bi surfactant during the growth of InAsSb on the composition was examined, and it was found that increasing Bi flux on the surface during growth inhibits the incorporation of Sb. Analysis of the data via a kinetic model of anion incorporation shows that surface Bi acts as a catalyst for InAs formation, thus inhibiting Sb incorporation. [ABSTRACT FROM AUTHOR]

We present a kinetic model predicting anion incorporation in InAsSb. Included are the effects of As desorption, Sb segregation, and Sb displacement by As, any of which may be limited by the In flux if it is comparatively larger. The model captures experimental data over a range of growth conditions for the InAsSb system using activation energies for desorption and Sb segregation found in literature. The activation energy for Sb displacement found in this work is 1.3 eV. This model is general and should be valid for other mixed anion systems, or, appropriately modified, mixed cation systems and mixed anion/cation systems such as AlInAsSb. [ABSTRACT FROM AUTHOR]

Thin GaAs films grown on lattice-matched In0.53Ga0.47As/InP(001) have been imaged by in vacuo scanning tunneling microscopy. We observe that the morphological evolution of these strained films depends on the deposition and diffusion of group III adatoms and the incorporation of As from the vapor, in addition to Asaro–Tiller–Grinfeld instabilities. We compare step edge densities to a model for the Ga adatom density and find that the absolute magnitude of the group V and group III fluxes has a strong effect on the number of adatoms on the surface and, thus, the morphology of the films. [ABSTRACT FROM AUTHOR]

In vacuo scanning tunneling microscopy (STM) was used to image thin GaAs films grown on lattice-matched [In.sub.0.53][Ga.sub.0.47]As/InP(001). The observations showed that the morphological evolution of strained films depends on the deposition and diffusion of group III adatoms and the incorporation of As from the vapor, in addition to Asaro-Tiller-Grinfeld instabilities.

We have investigated the structure and shape of GaN-based nanowires grown on (001) Si substrates for optoelectronic device applications. The nanowire heterostructures contained InN disks and InGaN barrier layers in the active region. The resulting nanowire array comprised two differently shaped nanowires: shorter pencil-like nanowires and longer bead-like nanowires. The two different nanowire shapes evolve due to a variation in the In incorporation rate, which was faster for the bead-like nanowires. Both types of nanowires exhibited evidence of significant migration of both Ga and In during growth. Ga tended to diffuse away and down along the sidewalls, resulting in a Ga-rich shell for all nanowires. Despite the complex structure and great variability in the In composition, the optical properties of the nanowire arrays were very good, with strong luminescence peaking at ∼ 1.63 μm. [ABSTRACT FROM AUTHOR]