Effects of Thermal Activation on CNT Nanocomposite Electrical Conductivity and Rheology.

Carbon-based nanocomposites featuring enhanced electrical properties have seen increased adoption in applications involving electromagnetic interference shielding and electrostatic dissipation. As the commercialization of these materials grows, a thorough understanding of how thermal activation affects the rheology and electrical performance of CNT-epoxy blends can inform quality decisions throughout the production process. The aim of this work was the identification of the effects that thermal activation has on the electrical and rheological properties of uncured epoxy mixtures and how those may be tied to the resulting cured composites. Herein, three distinct CNT-loaded composite mixtures were characterized for changes in electrical resistivity and viscosity resulting from varying activation times. Electrical conductivity decreased as activation time increased. Uncured mixture viscosity exhibited a strong dependence on CNT loading and applied strain, with activation time being found to significantly reduce the viscosity of the uncured mixture and surface profile of cured composite films. In all cases, cured composites featured improved electrical conductivity over the uncured mixtures. Factors contributing to the observed behavior are discussed. Raman analysis, optical microscopy of CNT networks, and data from silica bead mixing and dispersion studies are presented to contextualize the results.

Introduction of Rare-Earth Oxide Nanoparticles in CNT-Based Nanocomposites for Improved Detection of Underlying CNT Network.

Epoxy resins for adhesive and structural applications are widely employed by various industries. The introduction of high aspect ratio nanometric conductive fillers, i.e., carbon nanotubes, are well studied and are known to improve the electrical properties of the bulk material by orders of magnitude. This improved electrical conductivity has made carbon nanotube-based nanocomposites an attractive material for applications where their weight savings are at a premium. However, the analytical methods for validating carbon nanotube (CNT) nanofiller dispersion and for assuring that the properties they induce extend to the entire volume are destructive and inhibited by poor resolution between matrix and tube bundles. Herein, rare-earth oxide nanoparticles are synthesized on CNT walls for the purpose of increasing the contrast between their network and the surrounding matrix when studied by imaging techniques, alleviating these issues. The adherence of the synthesized nanoparticles to the CNT walls is documented via transmission electron microscopy. The crystalline phases generated during the various fabrication steps are determined using X-ray diffraction. Deep ultraviolet-induced fluorescence of the Eu:Y2O3-CNT nanostructures is verified. The impacts to nanocomposite electrical properties resulting from dopant introduction are characterized. The scanning electron microscopy imaging of CNT pulp and nanocomposites fabricated from untreated CNTs and Eu:Y2O3-CNTs are compared, resulting in improved contrast and detection of CNT bundles. The micro-CT scans of composites with similar results are presented for discussion.

Introducing clinical laboratory science: CLS students help shape the future.

OBJECTIVES: The profession of clinical laboratory science (CLS) is in dire need of increased exposure to young people. By introducing the clinical laboratory sciences to students at a critical point in their science education and by making it relevant to their lives, more choices are made available to them when considering future career options. With this in mind, the CLS faculty at Texas Tech University Health Sciences Center (TTUHSC) redesigned a recruitment program and developed it into one making use of CLS student knowledge, enthusiasm, and professionalism. CLS students were given the assignment of designing an entire curriculum for a ten day presentation of clinical laboratory science topics to middle and secondary school students. Following the presentations, participants in the program were asked to provide feedback regarding CLS student performance and overall opinion of their interest in clinical laboratory science. The objectives of this study were twofold: 1) to determine if educational methodologies could be appropriately applied by CLS students to present CLS disciplines to middle and high school students; and 2) to determine if the student presentation was successful in initiating interest in the CLS profession based on outcome measures. DESIGN: As a component of the CLS laboratory management course, CLS students were instructed in education methodologies including objective writing, teaching-unit preparation, and evaluation tool design. In the following semester, these students were divided into groups and assigned a specific CLS discipline that would then be presented to middle and secondary school students in a two week, 30 hour educational program. This program was offered by the TTUHSC CLS program in cooperation with the Institute for the Development and Enrichment of Advanced Learners (IDEAL) at Texas Tech University. The curriculum prepared by the CLS students (with faculty supervision) provided the framework for the present study. SETTING: Didactic instruction of the CLS students regarding objective writing, curriculum design, and preparation of evaluations was included as a component of a CLS laboratory management course. The educational program presented by IDEAL in conjunction with the TTUHSC CLS program within the School of Allied Health Sciences occurred in the CLS student laboratories located in Lubbock, Texas. PARTICIPANTS: TTUHSC senior CLS students in a 2 + 2 baccalaureate level CLS program acted as instructors in the educational program which was presented to middle and secondary school students from around the region. CLS program faculty served as supervisors of this program. MAIN OUTCOME MEASURES: Questionnaires with Likert-scaled responses were used to evaluate outcomes. These questionnaires regarded 1) faculty assessment of CLS student performance relative to instruction in education methods; 2) participant feedback on the effectiveness and competence of the CLS student instructors and overall appeal of the presented subject material; and 3) peer evaluations of attitude, contribution, and effort of the group members. RESULTS: CLS faculty strongly agreed that the CLS students demonstrated a high level of competence when writing objectives, planning age-appropriate curriculum and activities, and demonstrating a positive image of the profession. Regarding satisfaction of the IDEAL student participant, questionnaire responses demonstrated a high rate (84% or greater for middle school participants and 85% for high school students). The program design has been so successful that it has been implemented for several other programs offered by TTU and IDEAL. CONCLUSION: The education methods used in presenting the IDEAL program mirror those found in clinical and academic settings and is an effective technique to introduce CLS students to the varied aspects of educational methodology. The presentation by the CLS students also demonstrated that introduction of clinical laboratory science disciplines early in the education of middle and secondary school students leads to an interest in the CLS profession and to the desire to learn more about it.

Clinical laboratory science: A profession with honors.

Texas Tech University Health Science Center (TTUHSC) supports a strong undergraduate honors program. Students are required to enter the Honors College as freshmen and enroll in at least 24 hours of honors-designated classes. Some of the clinical core courses in the clinical laboratory science (CLS) program are designated as honors courses so students can continue their contract agreement with the Honors College to enroll in at least six hours of honors credit at the junior and senior level. By providing further educational experiences out of class, these honors students are able to meet the requirements needed to graduate with highest honors. A CLS honors program not only benefits the student but also the faculty involved and the program curriculum.