TEF, Vol. 2 No. 1

The second annual literary anthology of students writing from Stephen F Austin State College.https://scholarworks.sfasu.edu/tef/1001/thumbnail.jp

Phonon engineering for nanostructures.

Understanding the physics of phonon transport at small length scales is increasingly important for basic research in nanoelectronics, optoelectronics, nanomechanics, and thermoelectrics. We conducted several studies to develop an understanding of phonon behavior in very small structures. This report describes the modeling, experimental, and fabrication activities used to explore phonon transport across and along material interfaces and through nanopatterned structures. Toward the understanding of phonon transport across interfaces, we computed the Kapitza conductance for {Sigma}29(001) and {Sigma}3(111) interfaces in silicon, fabricated the interfaces in single-crystal silicon substrates, and used picosecond laser pulses to image the thermal waves crossing the interfaces. Toward the understanding of phonon transport along interfaces, we designed and fabricated a unique differential test structure that can measure the proportion of specular to diffuse thermal phonon scattering from silicon surfaces. Phonon-scale simulation of the test ligaments, as well as continuum scale modeling of the complete experiment, confirmed its sensitivity to surface scattering. To further our understanding of phonon transport through nanostructures, we fabricated microscale-patterned structures in diamond thin films

Design and evaluation: end users, user datasets and personas

Understanding the needs and aspirations of a suitable range of users during the product design process is an extremely difficult task. Methods such as ethnographic studies can be used to gain a better understanding of users needs, but they are inherently time consuming and expensive. The time pressures that are evident in the work performed by design consultancies often make these techniques impractical. This paper contains a discussion about the use of 'personas', a method used by designers to overcome these issues. Personas are descriptive models of archetypal users derived from user research. The discussion focuses on two case studies, the first of which examines the use of personas in the car design process. The second examines the use of personas in the field of 'inclusive design', as demonstrated by the HADRIAN system. These case studies exemplify the benefits 'data rich' personas contribute as opposed to 'assumption based' personas. © 2013 Elsevier Ltd and The Ergonomics Society

Controlled, parametric, individualized, 2-D and 3-D imaging measurements of aerosol deposition in the respiratory tract of healthy human subjects for model validation

Computer modeling is used widely to predict inhaled aerosol deposition in the human lung based on definition of the input conditions describing the aerosol characteristics, the breathing pattern and the airway anatomy of the subject. Validation of the models is limited by the lack of detailed experimental data. Three dimensional imaging data provides an opportunity to address this unmet need. Radioactive aerosol was administered to each of 11 healthy male subjects on two occasions under carefully monitored input conditions. Input parameters varied were particle size, depth of breathing, carrier gas and posture. The aerosol distribution was measured by combined single photon emission computed tomography and X-ray computer tomography (SPECT/CT). Airway anatomy was determined by high resolution CT imaging. The distribution of deposition was determined by a combination of 2D and 3D analysis and described in terms of the percentage of inhaled aerosol deposited in sections of the respiratory tract and in both spatial and anatomical sub-divisions within each lung. The percentage deposition in the conducting airways was also assessed by 24 h clearance. A set of imaging data of aerosol deposition has been produced in which the input parameters of inhalation are well described. The parameters were varied in a controlled manner to allow the sensitivity of predictive models to different factors to be tested. An initial analysis of the data is presented which will act as a guide that other centers can use to compare their own methodology. This data is considered to be of great potential value to computer modelers of aerosol deposition in validating their models