Development of a Survey to Assess K‐12 Teachers' Perceptions of Engineers and Familiarity with Teaching Design,Engineering, and Technology

This paper describes the development of a survey instrument to assess K‐12 teachers' perceptions of engineering and their familiarity with teaching design, engineering, and technology (DET). Item development, field testing, and the factor analysis are described along with reliability and validity. Administration of the instrument revealed differences based on gender, grade level taught, and years of teaching experience. Female teachers rated the importance of DET higher than male teachers, elementary teachers were least likely to teach DET, and moderately experienced teachers were the most willing to learn more about DET. Barriers to infusing DET into the curriculum were time and administrative support. All teachers were unfamiliar with DET, lacked confidence in their ability to teach DET, and held stereotypes about the skills needed to be an engineer. Based on the findings, recommendations are made for professional development of K‐12 teachers and for the pre‐service teacher preparation curriculum.     

X-Ray Microanalysis in the Variable Pressure (Environmental) Scanning Electron Microscope

Electron-excited x-ray microanalysis performed in the variable pressure and environmental scanning electron microscopes is subject to additional artifacts beyond those encountered in the conventional scanning electron microscope. Gas scattering leads to direct contributions to the spectrum from the environmental gas, as well as remote generation of x rays by electrons scattered out of the focussed beam. The analyst can exert some degree of control over these artifacts, but depending on the exact situation, spurious elements can appear at the trace (< 0.01 mass fraction), minor (0.01 mass fraction to 0.1 mass fraction), or even major (> 0.1 mass fraction) levels. Dispersed particle samples give the least compromised results, while fine scale microstructures are the most severely compromised. Procedures to optimize the situation based upon specimen preparation as well as spectral processing are described.     

Sr2YRu1?uCuuO6: Evidence for SrO-Layer Superconductivity

Sr₂YRuO₆ doped on its Ru site by Cu superconducts at the below 45 K, although its Ru and Cu are magnetically ordered at 23 K and 86 K, respectively. The SrO layers superconduct. Ba₂GdRuO₆, when doped with Cu, does not superconduct, because L = 0 Gd is not crystal-field split, and so induces Cooper pair-breaking.     

Severe plastic deformation (SPD) and nanostructured materials by machining

Large plastic strains between 1 and 15 can be imposed in chips formed by plane-strain (2-D) machining of metals and alloys. This approach has been used to examine microstructure changes induced by large strain deformation in model systems—copper and its alloys, precipitation-hardenable aluminum alloys, high-strength materials such as titanium, Inconel 718 and 52100 steel, and an amorphous alloy. It is shown that materials with average grain sizes in the range of 60 nm–1 μm can be created by varying the parameters of machining, which in turn affects the deformation processes. Furthermore, a switch-over from an elongated subgrain microstructure to an equi-axed nanocrystalline microstructure, with a preponderance of large-angle grain boundaries, has been demonstrated at the higher levels of strain in several of these materials. This switch-over can be readily controlled by varying the deformation conditions. Dynamic recrystallization has been demonstrated in select material systems under particular conditions of strain and temperature. This study may be seen as providing an important bridge between furthering the understanding of microstructural refinement by large strain deformation and the practical utilization of nanostructured materials in structural and mechanical applications. Conventional plane-strain machining has been shown to be a viable SPD method for examining the underlying processes of very large strain deformation.     

Repurposing Cyanine NIR‐I Dyes Accelerates Clinical Translation of Near‐Infrared‐II (NIR‐II) Bioimaging

The significantly reduced tissue autofluorescence and scattering in the NIR‐II region (1000–1700 nm) opens many exciting avenues for detailed investigation of biological processes in vivo. However, the existing NIR‐II fluorescent agents, including many molecular dyes and inorganic nanomaterials, are primarily focused on complicated synthesis routes and unknown immunogenic responses with limited potential for clinical translation. Herein, the >1000 nm tail emission of conventional biocompatible NIR cyanine dyes with emission peaks at 700–900 nm is systematically investigated, and a type of bright dye for NIR‐II imaging with high potential for accelerating clinical translation is identified. The asymmetry of the π domain in the S₁ state of NIR cyanine dyes is proven to result in a twisted intramolecular charge‐transfer process and NIR‐II emission, establishing a general rule to guide future NIR‐I/II fluorophore synthesis. The screened NIR dyes are identified to possess a bright emission tail in the NIR‐II region along with high quantum yield, high molar‐extinction coefficient, rapid fecal excretion, and functional groups amenable for bioconjugation. As a result, NIR cyanine dyes can be used for NIR‐II imaging to afford superior contrast and real‐time imaging of several biological models, facilitating the translation of NIR‐II bioimaging to clinical theranostic applications.     

Older drivers’ crashes in Queensland,Australia

Background

The growing proportion of older adults in Australia is predicted to comprise 23% of the population by 2030. Accordingly, an increasing number of older drivers and fatal crashes of these drivers could also be expected. While the cognitive and physiological limitations of ageing and their road safety implications have been widely documented, research has generally considered older drivers as a homogeneous group. Knowledge of age-related crash trends within the older driver group itself is currently limited.

Objective

The aim of this research was to identify age-related differences in serious road crashes of older drivers. This was achieved by comparing crash characteristics between older and younger drivers and between sub-groups of older drivers. Particular attention was paid to serious crashes (crashes resulting in hospitalisation and fatalities) as they place the greatest burden on the Australian health system.

Method

Using Queensland Crash data, a total of 191,709 crashes of all-aged drivers (17–80+) over a 9-year period were analysed. Crash patterns of drivers’ aged 17–24, 25–39, 40–49, 50–59, 60–69, 70–79 and 80+ were compared in terms of crash severity (e.g., fatal), at fault levels, traffic control measures (e.g., stop signs) and road features (e.g., intersections). Crashes of older driver sub-groups (60–69, 70–79, 80+) were also compared to those of middle-aged drivers (40–49 and 50–59 combined, who were identified as the safest driving cohort) with respect to crash-related traffic control features and other factors (e.g., speed). Confounding factors including speed and crash nature (e.g., sideswipe) were controlled for.

Results and discussion

Results indicated that patterns of serious crashes, as a function of crash severity, at-fault levels, road conditions and traffic control measures, differed significantly between age groups. As a group, older drivers (60+) represented the greatest proportion of crashes resulting in fatalities and hospitalisation, as well as those involving uncontrolled intersections and failure to give way. The opposite was found for middle-aged drivers, although they had the highest proportion of alcohol and speed-related crashes when compared to older drivers. Among all older drivers, those aged 60–69 were least likely to be involved in or the cause of crashes, but most likely to crash at interchanges and as a result of driving while fatigued or after consuming alcohol. Drivers aged 70–79 represented a mid-range level of crash involvement and culpability, and were most likely to crash at stop and give way signs. Drivers aged 80 years and beyond were most likely to be seriously injured or killed in, and at-fault for, crashes, and had the greatest number of crashes at both conventional and circular intersections. Overall, our findings highlight the heterogeneity of older drivers’ crash patterns and suggest that age-related differences must be considered in measures designed to improve older driver safety.     

Low velocity impact and compression after impact characterization of woven carbon/vinylester at dry and water saturated conditions

The low velocity impact response and compression after impact strength of dry and water saturated plain weave carbon/vinylester composites have been determined. The composites employed T700 carbon fibers and vinylester 510A and 8084 resins. Quasi-static impact tests were conducted on dry C/VE510A and C/VE8084 to estimate the threshold impact force required to initiate damage in the composites. Falling-weight impact tests were conducted on the composites over a range of impact energies from 6.7 to 47 J. Destructive inspection of damaged panels revealed damage in the form of matrix cracks as well as delamination between fiber bundles. The quasi-static estimation of the threshold impact force was in reasonable agreement with that measured in the impact test. To examine structural degradation due to impact loading, impacted panels were tested in compression (CAI). The CAI strength decreased with increasing impact energy. Absorbed moisture caused further reductions of the CAI strength.     

Formation of Metal Nanoparticles Directly from Bulk Sources Using Ultrasound and Application to E‐Waste Upcycling

A method for creating nanoparticles directly from bulk metal by applying ultrasound to the surface in the presence of a two‐part surfactant system is presented. Implosive collapse of cavitation bubbles near the bulk metal surface generates powerful microjets, leading to material ejection. This liberated material is captured and stabilized by a surfactant bilayer in the form of nanoparticles. The method is characterized in detail using gold, but is also demonstrated on other metals and alloys, and is generally applicable. It is shown that nanoparticles can be produced regardless of the bulk metal form factor, and the method is extended to an environmentally important problem, the reclamation of gold from an electronic waste stream.     

Developing and Assessing Statewide Competencies for Engineering Design

An assessment system was developed and piloted in Washington state to evaluate the engineering design competence of community college transfer students and continuing students at Washington State University (WSU) and the University of Washington (UW). A multiple measured approach was employed consisting of a multiple-choice assessment, a team design performance assessment, and an essay, each administered to junior level students at WSU and UW. These assessments covered important design and design-related outcomes valued by the engineering community in Washington and expected of junior level engineering students. Scoring criteria were developed by engineering faculty for the team design and essay components. The assessment results provide faculty and other decision makers at community colleges and four-year institutions with data they need to determine the extent to which students are meeting design competency expectations. Moreover, the approach described in this paper illustrates how institutions can productively address the ABET Engineering Criteria 2000 requirements by developing the assessment support that engineering educators need to make informed programmatic decisions and achieve continuous quality improvement.